Journal articles on the topic 'Emitters'
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1
KOH, W. S., and L. K. ANG. "SIMULATION OF HIGH CURRENT FIELD EMISSION FROM VERTICALLY WELL-ALIGNED METALLIC CARBON NANOTUBES." International Journal of Nanoscience 03, no. 04n05 (August 2004): 677–84. http://dx.doi.org/10.1142/s0219581x04002528.
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We have studied the intense electron beams emitted from multiple metallic, vertical and well-aligned Carbon Nanotube (CNT) field emitters. A two-dimensional (2D) particle-in-cell simulation code MAGIC2D is used to obtain the I–V characteristics near to the apex of the emitters' surface for a given applied electric field and field enhancement factor over a wide range of parameters. The effects of electron space charge and electric field shielding from neighboring emitters are compared in low current and high current regimes. It is found that the electron space charge is dominant in high current regime, where the Fowler–Nordheim (FN) law becomes the 2D Child–Langmuir (CL) law. The emitter spacing, number of emitters, and emitter's uniformity are also particularly studied, and they are more critical in low current regime. Smooth transition from the FN law to CL law is demonstrated.
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Li, Zhangyan, Liming Yu, Na Li, Liuhong Chang, and Ningbo Cui. "Influence of Flushing Velocity and Flushing Frequency on the Service Life of Labyrinth-Channel Emitters." Water 10, no. 11 (November 12, 2018): 1630. http://dx.doi.org/10.3390/w10111630.
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Dripline flushing is an effective way to relieve emitter clogging and extend the longevity of drip irrigation systems. This laboratory study was conducted at Kunming University of Science and Technology to evaluate the effect of three targeted flushing velocities (0.3, 0.6, and 0.9 m/s) and four flushing frequencies (no flushing, flushing daily, and flushing every three or five days) on the emitter’s service life and the particle size distribution of the sediment discharged from emitters and trapped in an emitter channel. The gradation of particle size was analyzed by a laser particle size analyzer. The experiment results suggested that flushing velocity and flushing frequency had a significant effect on the service life of emitters, and the emitter’s service life was extended by 30.40% on average under nine different flushing treatments. Flushing can effectively reduce the accumulation of sediments in the dripline and decrease the probability of coarse particles flowing into emitters and fine particles aggregating and cementing in the labyrinth channel, thus relieving the emitter clogging. Therefore, dripline flushing can effectively slow down clogging in muddy water drip irrigation system. The recommended flushing velocity should be set at 0.6 m/s, and the flushing intervals should be shortened.
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Almario-Narváez, Johana, Javier Enrique Vélez-Sánchez, and María Jaqueline Molina-Ochoa. "Emitter clogging when using water from a tributary of the Bogotá River in Colombia." Agronomía Colombiana 34, no. 2 (May 1, 2016): 260–66. http://dx.doi.org/10.15446/agron.colomb.v34n2.56890.
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An experiment was conducted to study the behavior of three types of emitters used in Colombia under real-work conditions using water from the Neusa River, a tributary of the Bogotá River. The emitters included: an in-line turbulent-flow emitter (E1), an integrated turbulent-flow emitter (E2), and an integrated self-regulated turbulent-flow emitter (E3). The operation and quality of the emitters were evaluated taking into account the flow decrease trend over time (RF), the flow reduction percentage of the emitters (qr), the coefficient of variation (Cv), the Christiansen uniformity coefficient (CU), and the emission uniformity (EU). The results indicated that the water quality in general affected the performance of the emitters over time, depending on the characteristics and properties of the emitters. The EU and CU decreased in the three emitter types as the experiment progressed and the Cv and qr increased. The E2 emitter showed a lower Cv and qr and a higher CU and EU than the E1 and E3 emitters.
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Zhou, Hongxu, Yunkai Li, Youheng Fang, Yang Xiao, and Qiang Li. "Assessment of Flat Emitter Anti-Clogging Performance in Drip Irrigation Systems." Transactions of the ASABE 62, no. 3 (2019): 641–53. http://dx.doi.org/10.13031/trans.13151.
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Abstract. Selecting drip emitters with excellent anti-clogging performance (AP) is vital to ensure the safe operation of drip irrigation systems. However, previous researchers have not reached a consensus on emitter selection and evaluation standards based on emitter AP. In this study, eight types of flat emitters were selected as experimental objects, and high-sand surface water was used as the water source to test the AP of emitters with three experimental treatments. The emitter total coefficient of evaluation index (ETEI) was applied to analyze the relative differences in AP of the emitters, and then the mechanism leading to those differences was explored. The results indicated that there were significant variations in AP among different emitters, and four evaluation indices had good consistency in evaluating emitter AP. Small-discharge emitters showed good anti-clogging ability. Emitters with large cross-section average velocity (v), not just with high discharge (Q), should be identified as having excellent AP. The combination of emitter structural parameters, mainly width-depth ratio (W/D), relative radius (A1/2/L), and flow path length (L), made significant differences in the v of emitters under the same operating conditions. Higher v caused a significant linear decrease in key clogging components, solid particles (SD), CaCO3 and MgCO3 precipitates (C-MP), extracellular polymeric substances (EPS), and microbial activity (MA), of the clogging material inside the emitter. This study provides a reference for the selection and development of emitter products with high-efficiency AP. Keywords: Anti-clogging ability, Emitter discharge, Evaluation indices, Micro-irrigation, Uniformity.
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Santalices, David, Juan Meléndez, and Susana Briz. "Virtual Spectral Selectivity in a Modulated Thermal Infrared Emitter with Lock-In Detection." Sensors 22, no. 14 (July 21, 2022): 5451. http://dx.doi.org/10.3390/s22145451.
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The need for affordable low-power devices has led MEMS-based thermal emitters to become an interesting option for optical gas sensors. Since these emitters have a low thermal mass, they can be easily modulated and combined with a lock-in amplifier for detection. In this paper, we show that the signal measured by a lock-in amplifier from a thermal emitter that varies its temperature periodically can have different spectral profiles, depending on the reference signal used. These virtual emitters appear because the Fourier series expansion of the emitted radiance, as a function of time, has different coefficients for each wavelength, and this spectral signature, which is different for each harmonic, can be retrieved using a reference signal that corresponds to its frequency. In this study, the effect is first proved theoretically and then is measured experimentally. For this purpose, we performed measurements with an IR camera provided with six different spectral filters of a modulated emitter, in combination with lock-in amplification via software. Finally, we show a potential application of this effect using multiple virtual emitters to gain spectral selectivity and distinguish between two gases, CO2 and CH4.
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Filippov, Sergey V., Fernando F. Dall’Agnol, Eugeni O. Popov, Anatoly G. Kolosko, and Thiago A. de Assis. "Reaching homogeneous field emission current from clusters of emitters with nonuniform heights." Journal of Vacuum Science & Technology B 41, no. 1 (January 2023): 010601. http://dx.doi.org/10.1116/6.0002315.
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In field electron emission from pointed structures in a cluster or in an array, electrostatic depolarization due to neighboring emitters diminishes the local field enhancement factor (FEF). This effect can limit the maximum macroscopic emission current from devices. If emitters in a cluster are regularly spaced and uniformly tall, the local FEF will always present significantly larger values at the edges, making most of the cluster ineffective. In this work, we explore conducting emitters in a cluster that are not uniformly tall and numerically calculate the local electrostatic field and the macroscopic emitted current over classical emitter’s surfaces using the Murphy–Good emission model. Our results show the conditions to homogenize and, therefore, optimize the emission current extractable from the cluster.
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Anttu, Nicklas, Henrik Mäntynen, Anastasiia Sorokina, Pyry Kivisaari, Toufik Sadi, and Harri Lipsanen. "Geometry Tailoring of Emission from Semiconductor Nanowires and Nanocones." Photonics 7, no. 2 (March 26, 2020): 23. http://dx.doi.org/10.3390/photonics7020023.
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Semiconductor nanowires are of interest as light emitters in applications such as light-emitting diodes and single-photon sources. Due to the three-dimensional geometry in combination with a size comparable to the wavelength of the emitted light, nanowires have shown strong scattering effects for the emitted light. Here, we demonstrate with electromagnetic modeling that the emission properties of nanowires/nanocones show a complicated dependence on the geometry of the nanowire/nanocone, the shape and position of the emitter region, and the polarization of the emitter. We show that with proper design, the extraction efficiency can close in on 80% for as-grown single nanowires/nanocones. Importantly, we demonstrate how the internal quantum efficiency of the emitter plays a large role in the design process. A considerably different geometry design approach should be undertaken at low and high internal quantum efficiency. Due to the complicated design optimization, we strongly recommend the use of electromagnetic modeling of the emission to give guidance for suitable designs before starting the fabrication and processing of nanowire/nanocone-based light emitters.
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Yasnohorodskyi, M. A. "The use of various materials as a metal component in a metamaterial thermophotovoltaic emitter." Radiotekhnika, no. 210 (September 28, 2022): 160–66. http://dx.doi.org/10.30837/rt.2022.3.210.13.
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Thermophotovoltaics (TPV) is a process by which photons emitted by a heat emitter are converted into electrical energy by a photovoltaic cell. Selective heat emitters that can survive temperatures at or above 1000°C have the potential to significantly improve the energy conversion efficiency of a PV cell by limiting the emission of photons with energies below the band gap energy of a photovoltaic cell.
Waste heat can be a valuable source of energy if we can find a way to harvest it efficiently. Deviations from ideal absorption and ideal blackbody behavior lead to light losses. For selective emitters, any light emitted at wavelengths outside the bandgap energy of the photovoltaic system may not be efficiently converted, reducing efficiency. In particular, it is difficult to avoid emission associated with phonon resonance for wavelengths in the deep infrared, which cannot be practically converted. An ideal emitter would not emit light at wavelengths other than the bandgap energy, and much TFP research is devoted to designing emitters that approximate better this narrow emission spectrum.
TPV systems usually consist of a heat source, a radiator and a waste heat removal system. TFV cells are placed between the emitter, often a metal or similar block, and the cooling system, often a passive radiator.
Efficiency, heat resistance and cost are the three main factors for choosing a TPF emitter. The efficiency is determined by the absorbed energy relative to the incoming radiation. High temperature operation is critical because efficiency increases with operating temperature. As the temperature of the emitter increases, the radiation of the black body shifts toward shorter waves, which allows for more efficient absorption by photocells. This paper demonstrates the feasibility of using materials such as platinum, gold, and nichrome as a metal component in a metamaterial emitter with respect to their absorption and thermal stability.
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Siwach, Pooja, P. Arumugam, S. Modi, L. S. Ferreira, and E. Maglione. "Proton emission study as a guide to astrophysical rp process." EPJ Web of Conferences 260 (2022): 11039. http://dx.doi.org/10.1051/epjconf/202226011039.
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Proton emitters play an important role in deciding the path of the astrophysical rapid proton capture (rp) process. The lifetime of these nuclei depends on several factors, like the deformation, angular momentum of the emitted proton, residual interaction between valence proton and neutron (especially in case of odd-odd nuclei) and so on. Therefore, it is worth to investigate the structure of proton emitters to understand the rp process path. However, due to lack of data in this exotic region, the theoretical models should be robust and the dependence on the free parameters should be minimal. In this direction, we have developed the first microscopic approach to study the triaxially deformed odd-odd proton emitters. The application of the developed approach to 108I, a recently observed proton emitter to investigate the end cycle of the rp process, is discussed.
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POHER, Claude, and Danielle POHER. "Transient Luminous Events, into the Stratosphere and the Mesosphere, observed during violent thunderstorms lightning, are explained thanks to laboratory jets of photons in air, occuring during emission of Gravitational Quanta." Advances in Social Sciences Research Journal 8, no. 5 (May 28, 2021): 261–81. http://dx.doi.org/10.14738/assrj.85.10216.
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Abstract : A Gravitational field emitter, as we patented in 2006, is composed of an “active” material squeezed between two metallic electrodes. The active material is superconducting, with conductive or insulating grains added inside, to get local electric fields during brief electric discharges made into that emitter. Along such a discharge, the emitter propels itself, by anisotropic re-emission of interacting Gravitational Quanta. These emitted quanta accelerate distant matter particles placed along their trajectory. With early YBCO superconducting material emitters, cooled down by liquid nitrogen, we observed systematically a bright emission of light into the bath. This light emission is caused by nitrogen molecules’ ionization by gravitational quanta push. In 2012, the partial superconducting behavior of natural Graphite, at room temperature, was discovered, so we built new emitters from Graphite. These shown the same propelling effect as the early ones made of YBCO, with a lower performance. Here we record and discuss light emission in the form of jets of photons, in air, at room temperature, and pressure, during strong electric discharges into Graphite based emitters. These results enhance the confirmation of predictions from our theoretical Quantum model of Inertia and Gravitation. They explain also the enigmatic Transient Luminous Events observed in the atmosphere over thunderstorms clouds.
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Lemetayer, J., C. Marion, D. Fabre, and F. Plouraboué. "Multi-inception patterns of emitter array/collector systems in DC corona discharge." Journal of Physics D: Applied Physics 55, no. 18 (February 7, 2022): 185203. http://dx.doi.org/10.1088/1361-6463/ac4e35.
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Abstract Multiple emitters systems have been previously used so as to increase charge density in the drift region, many times without producing sensible increment neither in total current nor ionic wind. This contribution focuses on analyzing the detailed physics behind this failure, that is named ‘multiple emitters un-scalability’. It is established that multiple emitters un-scalability is related to the inability of multiple corona discharge inceptions when increasing the emitter number and/or density. This confirms recent findings that corona discharge inception is shielded by electro-static interactions between emitters. This contribution demonstrates that this shielding can be balanced by emitter/collector electrostatic interactions depending on the considered configuration. For sufficiently close collector-emitter distances, ignition starts at the array center, whereas, on the contrary, when the collector is distant, the ignition not only starts at the array’s periphery but might also be limited there. It is also demonstrated that emitter/emitter electrostatic interactions can be balanced by emitter/collector ones, depending of their chosen configuration. This lead to a variety of multi-inception patterns, the condition of which are analyzed. Intermediate configurations for which the collector is neither sufficiently close nor distant from the emitter array center provide a variety of multi-inception patterns that are hereby analyzed. Combining finite element computations of multi-inception drift-diffusion modeling with experimental measurements, provides a coherent picture explaining why multiple emitters sources systems do not lead to full ignition, and also exhibit conditions for which it does, leading to multiple emitters scalable systems.
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Al-Mefleh, Naji K., Samer Talozi, and Khaled Abu Naser. "Assessment of Treated Wastewater Reuse in Drip Irrigation under Different Pressure Conditions." Water 13, no. 8 (April 9, 2021): 1033. http://dx.doi.org/10.3390/w13081033.
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This study aims to investigate the influence of treated wastewater (TWW) on the hydraulic performance of drip irrigation emitters. A field experiment was conducted in order to test two types of online emitters, a low pressure (LP) and a standard pressure (SP), at different working pressures (0.25 bar, 0.50 bar, and 1.00 bar) using TWW. The emitters were initially evaluated in the laboratory and the field for the discharge exponent (X), discharge coefficient (Kd), average emitter discharge (Qavg), coefficient of variation (CV), distribution uniformity (DU), the mean discharge ratio (Dra), and the main degree of clogging (DC). The main effect of the emitters on the hydraulic parameters of irrigation performance was not significant, while the operational pressure and operational time of irrigation had a significant effect. For the LP emitter, the average emitter discharge was 7.6, 7.7, and 7.8 Lh−1 at 0.25, 0.50, and 1.00 bar, respectively. For the SP emitter, the average emitter discharge was 7.6, 7.8, and 7.8 Lh−1 at 0.25, 0.50, and 1.00 bar, respectively. The EU values for the LP and SP emitters varied from low to moderate at 0.25 bar, as the EU values at 0.50 and 1.00 bar were considered high for both emitter types.
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Al-Mefleh, Naji K., Ibrahim Bashabsheh, Samer Talozi, and Taha A. Al-Issa. "Field evaluation of the performance of different irrigation emitter types using treated wastewater." Water Quality Research Journal 50, no. 3 (April 7, 2015): 240–51. http://dx.doi.org/10.2166/wqrjc.2015.043.
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Experimental tests are carried out to evaluate the impact of treated wastewater (TWW) on the discharge of five different types of emitters which are commonly used. Two water qualities, fresh water (FW) and treated wastewater, and five types of emitters, GR, Nein (NE), Edin (ED), Corona (CO), and Rain Bird (RB) are tested. The values of chemical properties for FW show mostly low clogging potential on emitter performance. The clogging potential for TWW varied from low to medium. The exception was for pH where there was severe clogging potential for both water types. The performance of emitters was tested by measuring the emitter discharge and estimating the average emitter discharge (Qavg), coefficient of variation (CV), emission uniformity coefficient (EU), and Christiansen uniformity coefficient (CU). The average discharges for different types of emitters were analyzed and compared at P ≤ 0.05. The CO and RB emitter types did not show any signs of clogging whereas the GR, NE, and ED emitter types showed signs of clogging. The results of CV, EU, and CU values showed that the performances of emitter types GR, NE, ED were classified as low or moderate clogging potential. In contrast, the CO and RB emitters were classified as moderate or high clogging potential.
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Olesiński, Adam, and Zbigniew Piotrowski. "An Adaptive Energy Saving Algorithm for an RSSI-Based Localization System in Mobile Radio Sensors." Sensors 21, no. 12 (June 9, 2021): 3987. http://dx.doi.org/10.3390/s21123987.
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In localization systems based on the emission of reference radio signals, an important issue related to the reliability of sensor operation is the problem of operating time and power of the emitted reference radio signal. There are many localization methods that have proven useful in practice and that use a reference radio signal for this purpose. In the issue of determining the location of radio emitters, various radio signal propagation models are used to determine the effective range and distance of the sensor-receiver from the radio emitter. This paper presents an adaptive power control algorithm for a transmitter, as a reference emitter, operating in power-saving mode. An important advantage of the presented solution is the adjustment of the localization system accuracy at the assumed level of energy radiated by radio emitters based on the RSSI signal received power estimation.
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Kim, Mounggon, Sang Kyu Jeon, Seok-Ho Hwang, Sang-shin Lee, Eunsun Yu, and Jun Yeob Lee. "Highly efficient and color tunable thermally activated delayed fluorescent emitters using a “twin emitter” molecular design." Chemical Communications 52, no. 2 (2016): 339–42. http://dx.doi.org/10.1039/c5cc07999c.
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Sokol, Julia, Jaya Narain, Jeffrey Costello, Tristan McLaurin, Dheekshita Kumar, and Amos G. Winter. "Analytical model for predicting activation pressure and flow rate of pressure-compensating inline drip emitters and its use in low-pressure emitter design." Irrigation Science 40, no. 2 (February 14, 2022): 217–37. http://dx.doi.org/10.1007/s00271-022-00771-5.
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AbstractDrip irrigation has the potential to help farmers increase crop production with lower on-farm water consumption than flood or sprinkler irrigation; yet, its high costs keep it out of reach for many smallholder farmers, who make up about 20$$\%$$ % of the world’s population. Pressure-compensating (PC) drip emitters enable uniform water delivery to all crops in a field by regulating the emitter flow rate, but typically require high pumping pressures, contributing to high capital and operating costs for the pump and power system. Redesigning PC emitters for lower pressure operation could enable more energy-efficient and affordable drip systems. However, the current lack of published design theory for PC emitters hinders the development of emitters with desired hydraulic performance. To address this gap, we present an analytical, parametric model for the hydraulic behavior (i.e., the flow rate versus pressure curve) of inline PC emitters before the flow-regulating regime. We combine this model with a validated prototyping method to demonstrate its utility in the design of PC emitters with target activation pressures and flow rates, and demonstrate a sample design that achieves 38$$\%$$ % lower activation pressure than commercial emitters with similar flow rates. The proposed model sheds light on the parametric relationships between PC emitter geometry and performance. It may inform R&D efforts in the irrigation industry and lead to improved emitter designs with low operating pressures, helping reduce drip system costs and increase access to drip irrigation among smallholder farmers.
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Zhang, Peng, Jeongho Park, Steven Fairchild, Nathaniel Lockwood, Yue Lau, John Ferguson, and Tyson Back. "Temperature Comparison of Looped and Vertical Carbon Nanotube Fibers during Field Emission." Applied Sciences 8, no. 7 (July 19, 2018): 1175. http://dx.doi.org/10.3390/app8071175.
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Carbon nanotube (CNT) fiber-based emitters have shown great potential to deliver stable, high current beams for various potential applications. Because of joule heating, CNT field emitters are heated to high temperatures during field emission. It is important to improve the thermal management of emitters to increase their reliability and prevent premature failure. This paper compares the field emission characteristics and the temperature distribution of a new configuration of a looped CNT fiber emitter with a traditional single vertical CNT fiber emitter. It is found that the maximum temperature of the looped fiber emitter (~300 °C) is significantly reduced compared to that of the vertical fiber (~600 °C) at the same emission current of 3 mA. The experimentally measured temperature distribution is compared with a recent theory on joule heating of a one-dimensional conductor. This study provides new insights into the design of high performance field emitters.
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Araujo, Ana C. S. de, José A. Frizzone, Antonio P. de Camargo, Diego J. de S. Pereira, Verônica G. M. L. de Melo, and Wagner W. A. Bombardelli. "Discharge sensitivity of collapsible drip tapes to water temperature." Revista Brasileira de Engenharia Agrícola e Ambiental 25, no. 1 (January 2021): 3–9. http://dx.doi.org/10.1590/1807-1929/agriambi.v25n1p3-9.
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ABSTRACT The objective of this study was to quantify the effect of water temperature variations on the discharge of collapsible thin-walled drip tapes with integrated non-pressure-compensating emitters. The tests were conducted in the laboratory using an automated test bench. Tests were performed to determine the discharge-pressure curves by varying the water temperature from 20 to 50 °C. Nine emitter models of three wall thicknesses (6, 8, and 9 MIL) were evaluated. The coefficients K and x of the discharge-pressure curves varied according to the water temperature. In flat emitters of turbulent flow (x < 0.5), the discharge decreased as the temperature increased. In the welded emitters of turbulent flow, several responses were observed. Regarding emitter D (x > 0.5), the discharge increased as the temperature was increased, while for emitter C (x < 0.5), the discharge decreased; the highest discharge variations occurred at pressures higher than 60 kPa. For embossed emitters, the discharge increased as a function of temperature, however, the greatest variation occurred at the lowest pressures. None of the emitters showed significant difference in the discharge variation due to wall thicknesses.
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Boo, Hyunpil, Jong-Han Lee, Min Gu Kang, KyungDong Lee, Seongtak Kim, Hae Chul Hwang, Wook Jung Hwang, et al. "Effect of High-Temperature Annealing on Ion-Implanted Silicon Solar Cells." International Journal of Photoenergy 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/921908.
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P-type and n-type wafers were implanted with phosphorus and boron, respectively, for emitter formation and were annealed subsequently at 950∼1050∘Cfor 30∼90 min for activation. Boron emitters were activated at1000∘Cor higher, while phosphorus emitters were activated at950∘C. QSSPC measurements show that the impliedVocof boron emitters increases about 15 mV and theJ01decreases by deep junction annealing even after the activation due to the reduced recombination in the emitter. However, for phosphorus emitters the impliedVocdecreases from 622 mV to 560 mV and theJ01increases with deep junction annealing. This is due to the abrupt decrease in the bulk lifetime of the p-type wafer itself from 178 μs to 14 μs. PC1D simulation based on these results shows that, for p-type implanted solar cells, increasing the annealing temperature and time abruptly decreases the efficiency (Δηabs=−1.3%), while, for n-type implanted solar cells, deep junction annealing increases the efficiency andVoc, especially (Δηabs=+0.4%) for backside emitter solar cells.
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Wolf, Jean, Randall Guensler, Simon Washington, and William Bachman. "High-Emitting Vehicle Characterization Using Regression Tree Analysis." Transportation Research Record: Journal of the Transportation Research Board 1641, no. 1 (January 1998): 58–65. http://dx.doi.org/10.3141/1641-07.
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A small fraction of motor vehicles on the roadway emit a disproportionate fraction of pollutant emissions, especially for carbon monoxide and hydrocarbons. Generally, these “high emitters” or “super emitters” exhibit higher emissions rates under all operating conditions than do “normal emitters.” Since the instantaneous emissions response between normal- and high-emitting vehicles can differ by one or more orders of magnitude, so do their average emissions over a “typical” trip. Identifying the proportion of normal- and high-emitting vehicles in an urban area and quantifying their emissions is vital for accurate emission inventory accounting. A methodology by which high and normal emitters can be classified is presented. Unlike previous emitter classification approaches, the approach is data driven and relies entirely on hot-stabilized emissions results. A statistical classification scheme, better known as hierarchical tree based regression, is used to separate vehicles into homogenous emitter categories. The approach is shown to have a number of advantages. First, it is flexible with respect to both the number of classes and types of variables used to identify classes. Second, it considers the influence of a large number of vehicle and technology attributes on emitter status. Third, it ensures that the highest emitters can be isolated from the normal emitters, so that separate emission rate models can be developed for these vehicles. Finally, the approach does not combine the effects of starts and hot-stabilized operations within the definition of high emitter, leading to a classification scheme whereby vehicles with poor start emissions characteristics will not be incorrectly classified as vehicles with poor hot-stabilized emission characteristics.
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Silva, Alisson Jadavi Pereira da, Eugênio Ferreira Coelho, Jarbas Honorio de Miranda, and Stephen Ray Workman. "Estimating water application efficiency for drip irrigation emitter patterns on banana." Pesquisa Agropecuária Brasileira 44, no. 7 (July 2009): 730–37. http://dx.doi.org/10.1590/s0100-204x2009000700013.
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The objective of this work was to evaluate root and water distribution in irrigated banana (Musa sp.), in order to determine the water application efficiency for different drip irrigation emitter patterns. Three drip emitter patterns were studied: two 4-L h-1 emitters per plant (T1), four 4-L h-1 emitters per plant (T2), and five 4-L h-1 emitters per plant (T3). The emitters were placed in a lateral line. In the treatment T3, the emitters formed a continuous strip. The cultivated area used was planted with banana cultivar BRS Tropical, with a 3-m spacing between rows and a 2.5-m spacing between plants. Soil moisture and root length data were collected during the first production cycle at five radial distances and depths, in a 0.20x0.20 m vertical grid. The experiment was carried out in a sandy clay loam Xanthic Hapludox. Soil moisture data were collected every 10 min for a period of five days using TDR probes. Water application efficiency was of 83, 88 and 92% for the systems with two, four and five emitters per plant, respectively. It was verified that an increase in the number of emitters in the lateral line promoted better root distribution, higher water extraction, and less deep percolation losses.
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Germershausen, Sven, Lars Bartholomäus, Ulf Seidel, Norbert Hanisch, Anja Schieferdecker, Karl Heinz Küsters, Martin Kittler, Mawuli Ametowobla, Florian Einsele, and Gerald Dallmann. "Investigation of Emitter Homogeneity on Laser Doped Emitters." Energy Procedia 8 (2011): 232–37. http://dx.doi.org/10.1016/j.egypro.2011.06.129.
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Li, Xiao Quan. "The Fabrication Study of Branched Cathode Electrode for Field Emitter in a FED Panel." Advanced Materials Research 459 (January 2012): 652–55. http://dx.doi.org/10.4028/www.scientific.net/amr.459.652.
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Using carbon nanotubes as field emitters, the field emission display panel with branched cathode electrode was fabricated. For the cathode faceplate, the branched cathode electrode was composed of the emitter conducting layer and the emitter supporting layer. On the emitter supporting layer surface the carbon nanotubes field emitters were prepared, and the emitter conducting layer would be covered with the emitter insulation layer. The applied cathode potential would be conducted by the emitter conducting layer, which could decrease the additional voltage drop. The good field emission characteristic for the fabricated field emission display panel was confirmed.
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Dudczyk, J., and A. Kawalec. "Specific emitter identification based on graphical representation of the distribution of radar signal parameters." Bulletin of the Polish Academy of Sciences Technical Sciences 63, no. 2 (June 1, 2015): 391–96. http://dx.doi.org/10.1515/bpasts-2015-0044.
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Abstract The article presents some possibilities of same type radar copies identification with the use of graphical representation. The procedure described by the authors is based on transformation and analysis of basic parameters distribution which are measured by the radar signal especially Pulse Repetition Interval. A radar intercept receiver passively collects incoming pulse samples from a number of unknown emitters. Information such as Pulse Repetition Interval, Angle of Arrival, Pulse Width, Radio Frequency and Doppler shifts are not usable. The most important objectives are to determine the number of emitters present and classify incoming pulses according to emitters. To classify radar emitters and precisely identification the copy of the same type of an emitter source in surrounding environment, we need to explore the detailed structure i.e. intra-pulse information, unintentional radiated electromagnetic emission and fractal features of a radar signal. An emitter has its own signal structure. This part of radar signal analysis is called Specific Emitter Identification. Utilization of some specific properties of electronic devices can cause heightening probability of a correct identification
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Li, Yanfei, Xianying Feng, Yandong Liu, Xingchang Han, Haiyang Liu, Yitian Sun, Hui Li, and Yining Xie. "Research on Hydraulic Properties and Energy Dissipation Mechanism of the Novel Water-Retaining Labyrinth Channel Emitters." Agronomy 12, no. 7 (July 19, 2022): 1708. http://dx.doi.org/10.3390/agronomy12071708.
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As a key component of a drip irrigation system, the performance of the drip irrigation emitters is mainly determined by the flow channel structures and structural parameters. In this study, a novel type of circular water-retaining labyrinth channel (CWRLC) structure emitter was proposed, inspired by the effect of roundabouts that make vehicles slow down and turn. Using the single-factor experiment method, the influence of the hydraulic performance of CWRLC emitters was researched under different circular radii. The internal flow characteristics and energy dissipation mechanism were analyzed by a computational fluid dynamics (CFD) simulation. It can be seen from the analysis that the energy dissipation abilities of the flow channel depend on the proportion of low-speed vortex areas. The larger the proportion of low-speed vortex areas, the smaller the flow index of the CWRLC emitter. Quadrate water-retaining labyrinth channel (QWRLC) and stellate water-retaining labyrinth channel (SWRLC) structures were obtained by structural improvements for increasing the proportion of low-speed vortex areas. The simulation results showed that the flow indexes of two improved structural emitters were significantly decreased. CWRLC, QWRLC, SWRLC, and widely used tooth labyrinth channel (TLC) emitters were manufactured by using technologies of electrical discharge machining (EDM) and injection molding (IM). The physical test results showed that the SWRLC emitter achieved the best hydraulic performance compared with the other three emitters. Therefore, the SWRLC emitter has a broad prospect of application in water-saving irrigation.
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AL-Dulaimi, B. A., and Sh M. AL-Mehmdy. "Effect of pipe type and Emitters discharge on performance criteria of surface drip irrigation system." IOP Conference Series: Earth and Environmental Science 904, no. 1 (November 1, 2021): 012013. http://dx.doi.org/10.1088/1755-1315/904/1/012013.
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Abstract A field experiment was conducted in Jazeerah Al-Ramadi/Al-Hamidiyah research station (latitude33^o 27^’ 〖 11.9 〗 ^(՚՚)N, longitude 43^o 23^’ ^(՚՚) E (duration 2020. This study was conducted to investigate the effect of pipe types and emitters discharge on performance criteria of surface drip irrigation system. Therefore, a two factorial experiment was set as randomized complete block design with three replications. The first factor included the type of pipes and emitters, namely Turbo, GR and T-Tape. While the second factor involved the emitters discharge which consist of two levels i.e., 4 (D4) and 8 (D8) L.h-1. The irrigation system was initially evaluated in the field before planting by testing three operating pressures (50, 100 and 150 Kpa) to determine the actual discharge of the emitters closed to their design discharge (4 and 8 L.h-1) for each emitter to calculate the manufacturing coefficient of variation (CV), distribution uniformity and the discharge variation ratio at each operating pressure. Results showed that the best discharge (Closed to design discharge of 4 L.h-1) was obtained at the 50 Kpa operating pressure which gave 3.99,3.90 and 3.81 L.h-1 when using the T-Tape pipe and GR and Turbo emitter compare when the discharge of 8L.h-1 has been used which gave 7.96, 7.84 and 7.59 L.h-1 when the former pipe and emitters were used. The best coefficient of variation was observed when the T-Tape pipe and GR and Turbo emitter were used with discharge of 4 L.h-1 up to 0.1300, 0.2200 and 0.2600 compare to 0.1300, 0.2700 and 0.3500 when the same former pipe and emitters were used with discharge of 8L. h-1. Similarly, the best distribution uniformity was obtained when the T-Tape pipe and GR and Turbo emitter has been used with discharge of 4 L.h-1 which gave 94.68, 91.74 and 90%. Likewise, the most acceptable variety discharge ratio was observed when the same prior pipe and emitters were used with discharge of 4 L.h-1 by giving 7.23, 11.90 and 12.19 %.
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Fisher, T. S., and D. G. Walker. "Thermal and Electrical Energy Transport and Conversion in Nanoscale Electron Field Emission Processes." Journal of Heat Transfer 124, no. 5 (September 11, 2002): 954–62. http://dx.doi.org/10.1115/1.1494091.
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This paper considers the theory of electron field emission from nanoscale emitters with particular focus on thermal and electrical energy transport. The foundational theory of field emission is explored, and a model is presented that accounts explicitly for the energy band curvature produced by nanoscale tip emitters. The results indicate that the inclusion of band curvature strongly influences the energetic distribution of electrons for emitter radii less than 50 nm. The energy exchange process between emitted and replacement electrons is shown to allow high local energy transfer rates that can be exploited in direct thermal-to-electrical energy conversion processes. The dependence of energy conversion rates on material and operational parameters is demonstrated. Throughout the paper, opportunities for further research involving nanoscale heat transfer, materials development, and modeling are highlighted.
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AL-agele, Hadi A., Lloyd Nackley, and Chad Higgins. "Testing Novel New Drip Emitter with Variable Diameters for a Variable Rate Drip Irrigation." Agriculture 11, no. 2 (January 20, 2021): 87. http://dx.doi.org/10.3390/agriculture11020087.
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This research presents a new variable rate drip irrigation (VRDI) emitter design that can monitor individual water drops. Conventional drip systems cannot monitor the individual water flow rate per emitter. Application uniformity for conventional drip emitters can be decreased by clogged emitters, irregular emitter orifices, and decreases in pressure. A VRDI emitter can overcome the irrigation challenges in the field by increasing water application uniformity for each plant and reducing water losses. Flow rate is affected by the diameter of the delivery pipe and the pressure of the irrigation delivery system. This study compares the volumetric water flow rate for conventional drip emitters and new VRDI emitters with variable diameters inner (1 mm, 1.2 mm, 1.4 mm, and 1.6 mm) and outside (3 mm, 3.5 mm, 4 mm, and 4.5 mm) with three pressures (34 kPa, 69 kPa, and 103 kPa). The tests revealed that the new VRDI emitter had flow rates that increased as the operating pressure increased similar to a conventional drip tube. The flow rate was slightly increased in the VRDI with pressure, but even this increase did not show large changes in the flow rate. The flow rate of the conventional drip tube was 88% larger than the VRDI emitter for all pressures (p < 0.05). However, operating pressure did not affect the drop sizes at the VRDI emitter, but the generalized linear mixed models (GLM) results show that volume per drop was impacted by the outside diameter of the VRDI outlet (p < 0.05). The interaction between the inner and outside diameter was also significant at p < 0.01, and the interaction between outside diameter and pressure was statistically significant at p < 0.01. The electronic components used to control our VRDI emitter are readily compatible with off-the-shelf data telemetry solutions; thus, each emitter could be controlled remotely and relay data to a centralized data repository or decision-maker, and a plurality of these emitters could be used to enable full-field scale VRDI.
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Hao, Fengzhen, Jiusheng Li, Zhen Wang, and Yanfeng Li. "Effect of Chlorination and Acidification on Clogging and Biofilm Formation in Drip Emitters Applying Secondary Sewage Effluent." Transactions of the ASABE 61, no. 4 (2018): 1351–63. http://dx.doi.org/10.13031/trans.12764.
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Abstract. The risk and inducing mechanism of emitter clogging vary with the types of ions in the irrigation water. The effectiveness of chlorination and acidification treatments in reducing emitter clogging has seldom been comparatively studied. The objective of this study was to quantify the influence of chlorination and acidification in reducing clogging in emitters applying secondary sewage effluent with different types of ions. Two types of emitters with plain channels and one type of emitter with a labyrinth structure were selected to investigate the clogging control strategy by measuring the dry weight of biofilm substance (DW) and the organic matter fraction in the biofilm and analyzing the mineral constituents of the clogging solids and the extracellular polymeric substance (EPS) of the attached biofilm. In general, chemical injection decreased the DW and EPS, resulting in less clogging than in emitters without chlorine and acid injection. For the emitter structures tested, chemical injection was more effective in controlling clogging in plain channel emitters than in labyrinth emitters. Different chemical injections produced similar mineral constituents of the clogging solids: quartz, calcium + magnesium carbonate, silicate, and iron oxide. Chlorine injection interval and targeted acidification pH are both important parameters in determining chemical injection schemes. Under the experimental conditions, weekly chlorination of sewage effluent acidified to pH 6.5 was more effective in reducing the growth and reproduction of microorganisms and the precipitation of solid particles in the drip emitters when applying sewage effluent containing high iron + calcium. However, when sewage effluent containing high calcium was used, acidification was more effective in removing the chemical precipitates. We conclude that the selection of chemical treatment strategies should consider the constituent ions in the sewage effluent. Keywords: Acid injection, Chlorine injection, Extracellular polymeric substance (EPS), Mineral constituents, Microirrigation.
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Vukic, Vladimir, and Predrag Osmokrovic. "Impact of forward emitter current gain and geometry of pnp power transistors on radiation tolerance of voltage regulators." Nuclear Technology and Radiation Protection 25, no. 3 (2010): 179–85. http://dx.doi.org/10.2298/ntrp1003179v.
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Low-dropout voltage regulators with various geometries and technological realisations of serial pnp power transistors were exposed to ionizing radiation. Although devices with vertical emitters were considered much less susceptible to the influence of radiation on forward emitter current gain than circuits with round emitters, the experiment showed a similar degradation of current gain in both cases. The main reason of high radiation susceptibility of the examined vertical serial pnp transistor is the implementation of an interdigitated emitter, with high perimeter-to-area ratio, causing the great increase of serial transistor?s base current, but a minor influence on the maximum output current. Transistors with round emitters with small perimeter-to-area ratio expressed a moderate current gain degradation, but a rapid fall of the emitter injection efficiency, causing a significant decrease of the maximum output current. Regardless of the similar forward emitter current gain degradation, reliability and operational characteristics of two types of low-dropout voltage regulators were completely different.
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Lezier, G., P. Koleják, J. F. Lampin, K. Postava, M. Vanwolleghem, and N. Tiercelin. "Fully reversible magnetoelectric voltage controlled THz polarization rotation in magnetostrictive spintronic emitters on PMN-PT." Applied Physics Letters 120, no. 15 (April 11, 2022): 152404. http://dx.doi.org/10.1063/5.0080372.
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THz polarization control upon generation is a crucially missing functionality. THz spintronic emitters based on the inverse spin Hall effect (ISHE) allow for this by the strict implicit orthogonality between their magnetization state and the emitted polarization. This control was until now only demonstrated using cumbersome external magnetic field biasing to impose a polarization direction. We present here an efficient voltage control of the polarization state of terahertz spintronic emitters. Using a ferromagnetic spin pumping multilayer exhibiting simultaneously strong uniaxial magnetic anisotropy and magnetostriction in a crossed configuration, an emitter is achieved where, in principle, the stable magnetization direction can be fully and reversibly controlled over a 90° angle span only by an electric voltage. To achieve this, an engineered rare-earth based ferromagnetic multilayer is deposited on a piezoelectric [Formula: see text] (PMN-PT) substrate. We demonstrate experimentally a reversible 70° THz polarization rotation by sweeping the substrate voltage over 400 V. This demonstration allows for a fully THz polarization controlled ISHE spintronic terahertz emitter not needing any control of the magnetic bias.
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Thebaldi, Michael S., Luiz A. Lima, Willian F. de Almeida, and Rafaella R. Andrade. "Backpressure effects on the flow-pressure relation of driplines." Engenharia Agrícola 36, no. 1 (February 2016): 55–62. http://dx.doi.org/10.1590/1809-4430-eng.agric.v36n1p55-62/2016.
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ABSTRACT For drip irrigation design and management, it is necessary to know the relation between flow and pressure acting on emitters. In the case of subsurface drip irrigation, the backpressure phenomenon may change the hydraulic characteristics of emitters. Thus, this study aimed at determining such relationship between flow and pressure of different driplines in surface and subsurface conditions; aiming to find possible differences in hydraulic behavior. We tested four emitter types; two pressure compensating (D5000 and Hydro PCND) and two non-pressure compensating (TalDrip and Jardiline). Emitter flow rates were attained in atmospheric conditions and submerged in water, in which submergence levels represented backpressure. Assays were performed using inlet pressures of 80, 100, 120, and 150 kPa for the Hydro PCND dripline and 25, 50, 100, and 150 kPa for the other ones; the backpressures were of 0.49, 1.47, 2.45, 4.41 and 6.37 kPa with four replications. The emitters had their proportionality constants and discharge exponents changed in submerged applications, representing backpressure effect. Non-pressure compensating emitters had their discharge exponent decreased, while in pressure compensating ones, it was increased. Backpressure reduced emitter flow rates at all evaluated pressures.
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Mostafa, Harby, and Wael Sultan. "Hydraulic evaluation of locally modified emitter under laboratory conditions." Journal of Water Supply: Research and Technology-Aqua 67, no. 3 (March 23, 2018): 291–96. http://dx.doi.org/10.2166/aqua.2018.123.
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Abstract Drip irrigation systems have become a major part of developing agriculture in Egypt and the aim of this research was to obtain the best performance from irrigation systems management using locally modified and original emitters. The experiments were carried out at the National Irrigation Laboratory of the Agricultural Engineering Research Institute. The emitters were tested and calibrated under different operating pressures (0.50, 0.75, 1 and 1.25 bar) to determine emitter flow rates and emitter emission uniformity (EU) and manufacturing variation coefficient (CV). The original emitter performance was determined using the relationship between emitter flow rate (2 lh−1) and operating pressure, with data indicating that the EU was 98.5%, at a CV of 2.3% and actual flow rate was 1.8 lh−1 for the original emitter. The EU was 93.8% with a CV of 5.2% and actual flow rate of 2.02 lh−1 for the modified emitter. For original emitter performance at 4 lh−1, data indicated that the EU was 96%, with a CV of 4.8% and actual flow rate of 3.78 lh−1. The EU for the modified emitter was 95% with a CV of 2.7% and actual flow rate of 4.5 lh−1. The emitter exponent values were 0.41 to 0.44 for modified and 0.37 to 0.38 for original emitters.
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Gerhardt, Ilja, Bernhard Grotz, Petr Siyushev, and Jörg Wrachtrup. "Coherent interaction of single molecules and plasmonic nanowires." International Journal of Modern Physics B 31, no. 24 (September 30, 2017): 1740004. http://dx.doi.org/10.1142/s0217979217400045.
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Quantum plasmonics opens the option to integrate complex quantum optical circuitry onto chip scale devices. In the past, often external light sources were used and nonclassical light was coupled in and out of plasmonic structures, such as hole arrays or waveguide structures. Another option to launch single plasmonic excitations is the coupling of single emitters in the direct proximity of, e.g., a silver or gold nanostructure. Here, we present our attempts to integrate the research of single emitters with wet-chemically grown silver nanowires. The emitters of choice are single organic dye molecules under cryogenic conditions, which are known to act as high-brightness and extremely narrow-band single photon sources. Another advantage is their high optical nonlinearity, such that they might mediate photon–photon interactions on the nanoscale. We report on the coupling of a single molecule fluorescence emission through the wire over the length of several wavelengths. The transmission of coherently emitted photons is proven by an extinction type experiment. As for influencing the spectral properties of a single emitter, we are able to show a remote change of the line-width of a single terrylene molecule, which is in close proximity to the nanowire.
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Patten, K. D., E. W. Neuendorff, A. T. Leonard, and V. A. Haby. "Mulch and Irrigation Placement Effects on Soil Chemistry Properties and Rabbiteye Blueberry Plants Irrigated with Sodic Water." Journal of the American Society for Horticultural Science 113, no. 1 (January 1988): 4–8. http://dx.doi.org/10.21273/jashs.113.1.4.
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Abstract ‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade) plants were grown for 3 years under a sodic irrigation regimen. Mulched and non-mulched plants were irrigated by one of three methods: one drip emitter at the base of the plant, two drip emitters on either side of the plant, or low-volume spray emitter (LVSE). There was a mulch × irrigation treatment interaction. Mulch increased the growth of drip-irrigated plants but not LVSE-irrigated plants. Salt-induced leaf chlorosis and necrosis was only evident on plants with no mulch and irrigated with two emitters. Under mulched soil, K, Na, Mg, Cl, electrical conductivity (ECe), and Na adsorption ratio (SAR) levels were several times lower and uniform throughout the soil profile compared to the non-mulched treatments. Maximum root-zone salinity was 3.7 dS·m−1 for two emitters without mulch and a minimum of 0.5 dS·m−1 for one emitter with mulch.
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Ranjan, Rakesh, Rajeev Sinha, Lav R. Khot, Gwen-Alyn Hoheisel, Matthew J. Grieshop, and Mark Ledebuhr. "Effect of Emitter Modifications on Spray Performance of a Solid Set Canopy Delivery System in a High-Density Apple Orchard." Sustainability 13, no. 23 (November 30, 2021): 13248. http://dx.doi.org/10.3390/su132313248.
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Optimally configured solid set canopy delivery systems (SSCDS) can provide adequate spray performance in high-density apple orchards with a minimized risk of off-target pesticide drift. SSCDS configured in a shower-down emitter arrangement have been reported to be the simplest and most economical system. However, existing off-the-shelf emitters used in shower-down configurations have resulted in minimal deposition in lower canopy zones. Therefore, this study was focused on the modifications of off-the-shelf emitters to obtain a desirable spray pattern for adequate spray deposition in all the canopy zones. The modifications include redesigning the impact plate of two existing micro-emitters. Field tests were conducted to evaluate the spray performance of SSCDS with the non-modified emitters (treatment: SD1 and SD3) and contrast the results with modified emitters (treatment: SD2 and SD4). While the treatments SD1 and SD3 had off-the-shelf emitters with swivel plate and static spreader, respectively, the treatment SD2 and SD4 had similar emitters with modified impactor plates. In each treatment block, the apple canopy was divided into six zones and sprayed with a 500 ppm fluorescent tracer solution. Mylar cards and water-sensitive paper samplers were placed on the adaxial and abaxial leaf surfaces in each canopy zone to quantify spray deposition and coverage, respectively. The SSCDS treatments retrofitted with modified emitters, i.e., SD2 and SD4, were observed to have uniform and numerically higher deposition and coverage compared to SD1 and SD3. The SSCDS treatment with modified static spreader (i.e., SD4) resulted in the highest overall spray deposition (1405.7 ± 156.4 ng cm−2 [mean ± standard error]) with improved mid (1121.6 ± 186.9 ng cm−2) and bottom (895.6 ± 149.3 ng cm−2) canopy deposition. Overall, the proposed emitter modification assisted in improved SSCDS spray performances and may be a way forward toward large-scale emplacements of such systems.
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Valdés, Raquel, Julián Miralles, Jesús Ochoa, Sebastián Bañón, and María Jesús Sánchez-Blanco. "The Number of Emitters Alters Salt Distribution and Root Growth in Potted Gerbera." HortScience 49, no. 2 (February 2014): 160–65. http://dx.doi.org/10.21273/hortsci.49.2.160.
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Potted gerberas were grown in a greenhouse with one, two, or four emitters (1.2 L·h−1) per pot and irrigated with water of two levels of salinity (1.5 dS·m−1 and 3 dS·m−1). All pots received the same volume of water. The aim was to determine whether the number of emitters per pot affects the distribution of roots and salts in the substrate (100% coconut fiber). We determined the electrical conductivity (EC) distribution at three different heights (upper, middle, and lower). We also studied the roots and EC horizontal distribution in four quadrants (southeast, southwest, northwest, and northeast). Shoot growth, leaf damage, plant water status, and photochemical capacity of photosystem II were also studied. Two or four emitters per pot reduced the leaching fraction compared with that observed with one emitter, improving both the amount and homogeneity of substrate moisture. In the two saline conditions used, the salt concentration in the substrate was irregular both vertically and horizontally, and the presence of roots in the horizontal quadrant sides was heterogeneous. Both of these behaviors decreased as the number of emitters per pot increased. Root growth was weakly related with the soluble salt content in the root zone. When saline water is used, two emitters per pot are to be recommended because the difference between using two and four emitters was very slight. The use of only one emitter reduced shoot and root growth and encouraged salt damage to leaves.
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Solé-Torres, Carles, Freddie R. Lamm, Miquel Duran-Ros, Gerard Arbat, Francisco Ramírez de Cartagena, and Jaume Puig-Bargués. "Assessment of Microirrigation Field Distribution Uniformity Procedures for Pressure-Compensating Emitters under Potential Clogging Conditions." Transactions of the ASABE 64, no. 3 (2021): 1063–71. http://dx.doi.org/10.13031/trans.14486.
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HighlightsDistribution uniformity of the lower quartile (DUlq) was assessed in three microirrigation subunits with three procedures that used different locations and different numbers of sampled emitters.Using reclaimed effluent as the water source, performance was periodically measured for a total duration of 1000 h.Emitter clogging and the locations of sampled emitters greatly affected DUlq.None of the procedures accurately assessed DUlq if more than 4% of the emitters were fully clogged.Abstract. Proper water distribution uniformity is important for successful use of microirrigation systems. Consequently, consistent system monitoring and periodic distribution uniformity assessments can help determine the performance of a microirrigation system and identify possible problems that should be corrected. When using irrigation water with a greater clogging risk, such as reclaimed effluent, emitter clogging can seriously affect distribution uniformity. In this study, distribution uniformity was measured at three times (0 h, 500 h, and 1000 h of operation) in a microirrigation system that used reclaimed effluent. Emitter discharge values were obtained for each emitter in the system (three subunits consisting of four driplines each with 226 pressure-compensating emitters on each dripline), and the distribution uniformity of the low quartile (DUlq) was calculated for each subunit. These comprehensive DUlq values were compared with those calculated by three estimation procedures developed by Merriam and Keller, Burt, and Juana et al., which use different sampling locations and different numbers of sampling points. Results showed strong influence of emitter clogging and the location of the sampled emitters on DUlq values. Using this data set, the Merriam and Keller procedure had the greatest root mean square error (RMSE = 41.8%), the Burt procedure resulted in an intermediate value (RMSE = 5.9%), and the Juana et al. procedure had the lowest (RMSE = 3.2%) when most of the completely clogged emitters (about 1% of the total) were located at the ends of the driplines. Further speculative analysis in which complete clogging was allowed to migrate to the farthest distal emitters for the Burt and Juana et al. procedures indicated that none of the procedures accurately assessed the actual complete DUlq. These results suggest that none of these procedures alone are successful at assessing system-wide distribution uniformity when substantial clogging exists. Keywords: Drip irrigation, Effluent, Emitter clogging, Flow variation, Wastewater.
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Liu, Jiang, and John J. Hren. "SEM and Field Mmission study of silicon field emitter array." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1140–41. http://dx.doi.org/10.1017/s042482010013033x.
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Arrays of nanometer-scale field emitters have recently become attractive candidates for device applications where high frequency and high current are desirable attributes. High emission current can be obtained from densely packed Spindt-type emitter arrays with very low extraction voltage. Concern with the optimum geometrical shape of each emitter and the fraction of active emitters, makes a combined study of field emission and scanning electron microscopy especially useful.Several geometrical structures, as well as several materials, have been used to fabricate the field emitter arrays. The present study concentrates on silicon-base emitters fabricated at the Microelectronics Center of North Carolina (MCNC). Each emitter has a pyramidal structure, fabricated by anisotropic chemical etching of highly doped (ND = 1017 cm−3) n-type silicon. Figure 1 shows a SEM micrograph of a typical Si field emitter with a radius of curvature less than 30 nm. The field required for electron emission, about 3 × 107 V/cm, is created by a relatively low voltage applied to the extraction gate, a metal film less than one micron distant and deposited over a dielectric layer of silicon oxide (Figures 2 and 3).
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Liu, Bai, Fang, Ni, Lu, and Xu. "A Pragmatic Bilayer Selective Emitter for Efficient Radiative Cooling under Direct Sunlight." Materials 12, no. 8 (April 12, 2019): 1208. http://dx.doi.org/10.3390/ma12081208.
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Radiative cooling can make the selective emitter cool below ambient temperature without any external energy. Recent advances in photonic crystal and metamaterial technology made a high-efficiency selective emitter achievable by precisely controlling the emitter’s Infrared emission spectrum. However, the high cost of the photonic crystals and meta-materials limit their application. Herein, an efficient bilayer selective emitter is prepared based on the molecular vibrations of functional nanoparticles. By optimizing the volume fraction of the functional nanoparticles, the bilayer selective emitter can theoretically cool 36.7 °C and 25.5 °C below the ambient temperature in the nighttime and daytime, respectively. Such an efficient cooling performance is comparable with the published photonic crystal and metamaterial selective emitters. The rooftop measurements show that the bilayer selective emitter is effective in the ambient air even under direct sunlight. The relatively low cost and excellent cooling performance enable the bilayer selective emitter to have great potential for a practical purpose.
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Carr, W. W., D. S. Sarma, M. R. Johnson, B. T. Do, V. A. Williamson, and W. A. Perkins. "Infrared Absorption Studies of Fabrics." Textile Research Journal 67, no. 10 (October 1997): 725–38. http://dx.doi.org/10.1177/004051759706701005.
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A technique is discussed in this paper for evaluating the performance of IR emitters in heating and drying fabrics. The efficiency of IR heating depends on both the fabric spectral absorption characteristics and the spectral emission of the infrared source. An FTIR spectrometer with an integrating sphere is used to measure the infrared absorptivities of fabrics over the range of wavelengths from 0.7 to 25 microns (the range of operation of commercial infrared emitters). Spectral absorptivities are used with the normalized emission characteristics of blackbody emitters to calculate average fabric absorptivities for blackbody emitter temperatures ranging from 500 to 3000 K. Overall radiant efficiencies for heating fabrics with blackbody emitters are calculated by multiplying average fabric absorptivities by the radiant efficiencies of emitters in converting input power to IR radiant output power. The effects of fabric characteristics on spectral absorptivities, average absorptivities, and overall radiant efficiencies are studied. Parameters include fiber type, fabric weight, moisture regain, fabric construction, and dyeing. The technique used in this investigation is useful in matching IR emitters with applications for the textile industry.
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Gritsienko, Alexander V., Aliaksandr Duleba, Mikhail V. Pugachev, Nikita S. Kurochkin, Igor I. Vlasov, Alexei G. Vitukhnovsky, and Alexandr Yu Kuntsevich. "Photodynamics of Bright Subnanosecond Emission from Pure Single-Photon Sources in Hexagonal Boron Nitride." Nanomaterials 12, no. 24 (December 19, 2022): 4495. http://dx.doi.org/10.3390/nano12244495.
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Bright and stable emitters of single indistinguishable photons are crucial for quantum technologies. The origin of the promising bright emitters recently observed in hexagonal boron nitride (hBN) still remains unclear. This study reports pure single-photon sources in multi-layered hBN at room temperature that demonstrate high emission rates. The quantum emitters are introduced with argon beam treatment and air annealing of mechanically exfoliated hBN flakes with thicknesses of 5–100 nm. Spectral and time-resolved measurements reveal the emitters have more than 1 GHz of excited-to-ground state transition rate. The observed photoswitching between dark and bright states indicates the strong sensitivity of the emitter to the electrostatic environment and the importance of the indirect excitation for the photodynamics.
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Shabbir, Abdul, Hanping Mao, Ikram Ullah, Noman Ali Buttar, Muhammad Ajmal, and Imran Ali Lakhiar. "Effects of Drip Irrigation Emitter Density with Various Irrigation Levels on Physiological Parameters, Root, Yield, and Quality of Cherry Tomato." Agronomy 10, no. 11 (October 30, 2020): 1685. http://dx.doi.org/10.3390/agronomy10111685.
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Root morphology and its components’ behavior could show a considerable response under multiple water application points per plant to help the ultimate effect of fruit yield and fruit quality. In this study, a comparison of a single emitter per plant was made with two, three, and four emitters per plant under drip irrigation and two irrigation levels (full irrigation 100% and deficit irrigation 75% of crop evapotranspiration) to investigate their effects on physiological parameters, root, yield, and their associated components for potted cherry tomato under greenhouse conditions in Jiangsu-China. The experimental results showed that the plants cultivated in the spring-summer planting season showed significantly higher results than the fall-winter planting season due to low temperatures in the fall-winter planting season. However, the response root length, root average diameter, root dry mass, leaf area index, photosynthetic rate, transpiration rate, fruit unit fresh weight, the number of fruits, and pH were increased by multiple emitters per plant over a single emitter per plant, but total soluble solids decreased. Besides, a decreasing trend was observed by deficit irrigation for both planting seasons, and vice versa for the case for tomato total soluble solids. Due to an increase in measured parameters for multiple emitters per plant over a single emitter per plant, the yield, water use efficiency, and water use efficiency biomass significantly increased by 18.1%, 17.6%, and 15.1%, respectively. The deficit irrigation caused a decrease in the yield of 5% and an increase in water use efficiency and water use efficiency biomass of 21.4% and 22.9%, respectively. Two, three, and four emitters per plant had no significant effects, and the obtained results were similar. Considering the root morphology, yield, water use efficiency, water use efficiency biomass, and fruit geometry and quality, two emitters per plant with deficit irrigation are recommended for potted cherry tomato under greenhouse conditions. The explanation for the increased biomass production of the plant, yield, and water use efficiency is that two emitters per plant (increased emitter density) reduced drought stress to the roots, causing increased root morphology and leaf area index and finally promoting the plant’s photosynthetic activity.
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Al-Rabadi, Anas, and Marwan Mousa. "Field emission - based many-valued processing using carbon nanotube controlled switches - Part 1: Fundamentals." Facta universitatis - series: Electronics and Energetics 25, no. 1 (2012): 1–14. http://dx.doi.org/10.2298/fuee1201001a.
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In this first part of the article, basics of field emission will be presented which will be utilized within the second part of the article for the architecture effectuation of new Carbon Nanotube (CNT) - based controlled nano switches. To implement the field emission CNT - based controlled switch, four field emission CNTs that have single carbon nanotubes as the emitters were tested; two with single-walled CNT and two with multiwalled CNT. A tube with a tungsten tip was also used for comparison. The Fowler- Nordheim analysis of the DC current-voltage data provided reasonable values for the sizes and local fields of emitters. It is also shown within the new implementation of the controlled switch that square-wave pulses from a single laser diode with 20 mW power and 658 nm wavelength which is focused on each emitter increased the emitted current by 5.2% with the CNT and 0.19% with the compared tungsten tip.
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Türschmann, Pierre, Hanna Le Jeannic, Signe F. Simonsen, Harald R. Haakh, Stephan Götzinger, Vahid Sandoghdar, Peter Lodahl, and Nir Rotenberg. "Coherent nonlinear optics of quantum emitters in nanophotonic waveguides." Nanophotonics 8, no. 10 (August 30, 2019): 1641–57. http://dx.doi.org/10.1515/nanoph-2019-0126.
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AbstractCoherent quantum optics, where the phase of a photon is not scrambled as it interacts with an emitter, lies at the heart of many quantum optical effects and emerging technologies. Solid-state emitters coupled to nanophotonic waveguides are a promising platform for quantum devices, as this element can be integrated into complex photonic chips. Yet, preserving the full coherence properties of the coupled emitter-waveguide system is challenging because of the complex and dynamic electromagnetic landscape found in the solid state. Here, we review progress toward coherent light-matter interactions with solid-state quantum emitters coupled to nanophotonic waveguides. We first lay down the theoretical foundation for coherent and nonlinear light-matter interactions of a two-level system in a quasi-one-dimensional system, and then benchmark experimental realizations. We discuss higher order nonlinearities that arise as a result of the addition of photons of different frequencies, more complex energy level schemes of the emitters, and the coupling of multiple emitters via a shared photonic mode. Throughout, we highlight protocols for applications and novel effects that are based on these coherent interactions, the steps taken toward their realization, and the challenges that remain to be overcome.
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Kongsuwan, Nuttawut, Angela Demetriadou, Rohit Chikkaraddy, Jeremy J. Baumberg, and Ortwin Hess. "Fluorescence enhancement and strong-coupling in faceted plasmonic nanocavities." EPJ Applied Metamaterials 5 (2018): 6. http://dx.doi.org/10.1051/epjam/2018004.
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Emission properties of a quantum emitter can be significantly modified inside nanometre-sized gaps between two plasmonic nanostructures. This forms a nanoscopic optical cavity which allows single-molecule detection and single-molecule strong-coupling at room temperature. However, plasmonic resonances of a plasmonic nanocavity are highly sensitive to the exact gap morphology. In this article, we shed light on the effect of gap morphology on the plasmonic resonances of a faceted nanoparticle-on-mirror (NPoM) nanocavity and their interaction with quantum emitters. We find that with increasing facet width the NPoM nanocavity provides weaker field enhancement and thus less coupling strength to a single quantum emitter since the effective mode volume increases with the facet width. However, if multiple emitters are present, a faceted NPoM nanocavity is capable of accommodating a larger number of emitters, and hence the overall coupling strength is larger due to the collective and coherent energy exchange from all the emitters. Our findings pave the way to more efficient designs of nanocavities for room-temperature light-matter strong-coupling, thus providing a big step forward to a non-cryogenic platform for quantum technologies.
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Blum, Christian, Frank Schleifenbaum, Martijn Stopel, Sébastien Peter, Marcus Sackrow, Vinod Subramaniam, and Alfred J. Meixner. "Room temperature excitation spectroscopy of single quantum dots." Beilstein Journal of Nanotechnology 2 (August 30, 2011): 516–24. http://dx.doi.org/10.3762/bjnano.2.56.
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We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of 100 nm. The spectra exhibit emission intermittency, characteristic of single emitters. We observe large variations in the spectra close to the band edge, which represent the individual heterogeneity of the observed quantum dots. We also find specific excitation wavelengths for which the single quantum dots analyzed show an increased propensity for a transition to a long-lived dark state. We expect that the additional capability of recording excitation spectra at room temperature from single emitters will enable insights into the photophysics of emitters that so far have remained inaccessible.
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fraas, Lewis M., and Kuanrong Qiu. "Ceramic IR Emitter with Spectral Match to GaSb PV Cells for TPV." MRS Proceedings 1493 (2013): 11–22. http://dx.doi.org/10.1557/opl.2012.1706.
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ABSTRACTA high temperature ceramic selective emitter for thermophotovoltaic (TPV) electric generators is described with a spectral match to GaSb IR cells. While solar cells generate electricity quietly and are lightweight, traditional solar cells are used with sunlight and only generate electricity during the day. Workers at JX Crystals invented the GaSb IR cell as a booster cell to demonstrate a solar cell conversion efficiency of 35%. JX Crystals now makes these IR cells. In TPV, these cells can potentially be used with flame heated ceramic emitters to generate electricity quietly day and night. One of the most important requirements for TPV is a good spectral match between the ceramic IR emitted and the IR PV cells. The first problem is to find, demonstrate, and integrate a doped ceramic IR emitter with a spectral match to these GaSb cells. Recently, nickel oxide and cobalt oxide doped MgO-based ceramics have been shown experimentally and theoretically to have spectral selectivity but no attempts have been made to integrate these ceramic IR emitters into a fully operational TPV generator. Herein, we review the history of TPV and note that a key to future progress will be the integration of an appropriate ceramic emitter with cells and a burner to demonstrate an operational TPV generator. Integrating TPV into a residential boiler is discussed as a potential future large volume commercial market.
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Proscia, Nicholas V., Harishankar Jayakumar, Xiaochen Ge, Gabriel Lopez-Morales, Zav Shotan, Weidong Zhou, Carlos A. Meriles, and Vinod M. Menon. "Microcavity-coupled emitters in hexagonal boron nitride." Nanophotonics 9, no. 9 (May 24, 2020): 2937–44. http://dx.doi.org/10.1515/nanoph-2020-0187.
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AbstractIntegration of quantum emitters in photonic structures is an important step in the broader quest to generate and manipulate on-demand single photons via compact solid-state devices. Unfortunately, implementations relying on material platforms that also serve as the emitter host often suffer from a tradeoff between the desired emitter properties and the photonic system practicality and performance. Here, we demonstrate “pick and place” integration of a Si3N4 microdisk optical resonator with a bright emitter host in the form of ∼20-nm-thick hexagonal boron nitride (hBN). The film folds around the microdisk maximizing contact to ultimately form a hybrid hBN/Si3N4 structure. The local strain that develops in the hBN film at the resonator circumference deterministically activates a low density of defect emitters within the whispering gallery mode volume of the microdisk. These conditions allow us to demonstrate cavity-mediated out-coupling of emission from defect states in hBN through the microdisk cavity modes. Our results pave the route toward the development of chip-scale quantum photonic circuits with independent emitter/resonator optimization for active and passive functionalities.
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Cholsuk, Chanaprom, Sujin Suwanna, and Tobias Vogl. "Tailoring the Emission Wavelength of Color Centers in Hexagonal Boron Nitride for Quantum Applications." Nanomaterials 12, no. 14 (July 15, 2022): 2427. http://dx.doi.org/10.3390/nano12142427.
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Optical quantum technologies promise to revolutionize today’s information processing and sensors. Crucial to many quantum applications are efficient sources of pure single photons. For a quantum emitter to be used in such application, or for different quantum systems to be coupled to each other, the optical emission wavelength of the quantum emitter needs to be tailored. Here, we use density functional theory to calculate and manipulate the transition energy of fluorescent defects in the two-dimensional material hexagonal boron nitride. Our calculations feature the HSE06 functional which allows us to accurately predict the electronic band structures of 267 different defects. Moreover, using strain-tuning we can tailor the optical transition energy of suitable quantum emitters to match precisely that of quantum technology applications. We therefore not only provide a guide to make emitters for a specific application, but also have a promising pathway of tailoring quantum emitters that can couple to other solid-state qubit systems such as color centers in diamond.