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Добірка наукової літератури з теми "CNT MODEL FOR FIELD EMISSION"

Автор: Grafiati

Опубліковано: 11 вересня 2023

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Статті в журналах з теми "CNT MODEL FOR FIELD EMISSION"

Mahmood, Salman, Zainal Arif Burhanudin, and Nor Hisham Hamid. "Field Emission Model of CNT Based Ionization Gas Sensor." Advanced Materials Research 667 (March 2013): 135–43. http://dx.doi.org/10.4028/www.scientific.net/amr.667.135.

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A new model to study the gas detection mechanism of carbon nanotube (CNT) based ionization gas sensor has been developed. The model incorporates the effect of electron field emission due to the presence of CNT. The model is then embedded in the standard Particle-In-Cell / Monte-Carlo-Collision (PIC-MCC) codes. This enhanced PIC-MCC codes serve as a tool to optimize CNT based ionization gas sensor. The functionality of the new model is validated by running simulations of DC discharges in argon and comparing the results with published experimental and simulated works. From the simulation, one order of magnitude decrease in the breakdown voltages and three orders of magnitude faster response time was observed.

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Lee, Ha Rim, Da Woon Kim, Alfi Rodiansyah, Boklae Cho, Joonwon Lim, and Kyu Chang Park. "Investigation of the Effect of Structural Properties of a Vertically Standing CNT Cold Cathode on Electron Beam Brightness and Resolution of Secondary Electron Images." Nanomaterials 11, no. 8 (July 26, 2021): 1918. http://dx.doi.org/10.3390/nano11081918.

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Carbon nanotube (CNT)-based cold cathodes are promising sources of field emission electrons for advanced electron devices, particularly for ultra-high-resolution imaging systems, due to their high brightness and low energy spread. While the electron field emission properties of single-tip CNT cathodes have been intensively studied in the last few decades, a systematic study of the influencing factors on the electron beam properties of CNT cold cathodes and the resolution of the secondary electron images has been overlooked in this field. Here, we have systematically investigated the effect of the structural properties of a CNT cold cathode on the electron beam properties and resolution of secondary electron microscope (SEM) images. The aspect ratio (geometric factor) and the diameter of the tip of a vertically standing CNT cold cathode significantly affect the electron beam properties, including the beam size and brightness, and consequently determine the resolution of the secondary electron images obtained by SEM systems equipped with a CNT cold cathode module. Theoretical simulation elucidated the dependence of the structural features of CNT cold cathodes and electron beam properties on the contribution of edge-emitted electrons to the total field emission current. Investigating the correlations between the structural properties of CNT cold cathodes, the properties of the emitted electron beams, and the resolution of the secondary electron images captured by SEM equipped with CNT cold cathode modules is highly important and informative as a basic model.

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Ludwick, Jonathan, Nathaniel Hernandez, Geet Tripathi, Marc Cahay, Tyson Back, and Kevin L. Jensen. "Influence of thermal contact resistance on the field emission characteristics of a carbon nanotube." Journal of Vacuum Science & Technology B 40, no. 4 (July 2022): 042804. http://dx.doi.org/10.1116/6.0002001.

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A recent algorithm developed by Tripathi et al. [J. Appl. Phys. 128, 025017 (2020); Erratum, J. Appl. Phys. 131, 169901 (2022)] is modified to study the effects of thermal contact resistance on the field emission (FE) properties of a carbon nanotube (CNT). The model takes into account the temperature dependence of the CNT electrical and thermal conductivities. The boundary condition proposed by Huang et al. [Phys. Rev. Lett. 93, 7 (2004)] is used to include the effects of thermal contact resistance at a CNT/chuck interface located at [Formula: see text], i.e., [Formula: see text], where r is the CNT radius, [Formula: see text] is the heat conduction coefficient at [Formula: see text], and [Formula: see text] is the thermal resistivity of the CNT/chuck interface. The chuck is assumed to be a perfect heat sink at temperature [Formula: see text]. For a given set of CNT parameters and values of the applied external electric field, it is shown that current constriction at the CNT/chuck contact point leads to self-heating effects which increase with the value of the thermal contact resistance, leading to an increase in the temperature profile along the CNT (including the temperature at its tip) and the FE current above their values obtained assuming the CNT/chuck interface is at the heat sink temperature [Formula: see text]. The fractional change of the emission current versus applied external electric field is calculated for increasing values of the parameter [Formula: see text].

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Saleh, Tawfik A., Mohammad N. Siddiqui, and Abdulrahman A. Al-Arfaj. "Synthesis of Multiwalled Carbon Nanotubes-Titania Nanomaterial for Desulfurization of Model Fuel." Journal of Nanomaterials 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/940639.

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Анотація:

This work reported on the development of novel nanomaterials of multiwalled carbon nanotubes doped with titania (CNT/TiO2) for the adsorptive desulfurization of model fuel oils. Various analytical techniques such as field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of the nanomaterials. The initial results indicated the effectiveness of the prepared CNT/TiO2nanomaterials in removing sulfur compounds from model fuel oil. The adsorption of DBT, BT, and thiophene from model fuel onto the derived sorbents was performed using batch mode system. These CNT/TiO2nanomaterials initially afforded approximately 45% removal of DBT, 55% BT, and more than 65% thiophene compounds from model fuels. The CNT/TiO2nanomaterials provided an excellent activity towards interaction with organosulfur compounds. More experiments are underway to optimize the parameters for the adsorptive desulfurization processes. We believe that these nanomaterials as adsorbents will find useful applications in petroleum industry because of their operational simplicity, high efficiency, and high capacity.

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Zu, Yifan, Xuesong Yuan, Xiaotao Xu, Matthew T. Cole, Yu Zhang, Hailong Li, Yong Yin, Bin Wang, and Yang Yan. "Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode." Nanomaterials 9, no. 12 (December 12, 2019): 1768. http://dx.doi.org/10.3390/nano9121768.

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Carbon nanotube (CNT) cold cathodes are proving to be compelling candidates for miniaturized terahertz (THz) vacuum electronic devices (VEDs) owning to their superior field-emission (FE) characteristics. Here, we report on the development of a multi-sheet beam CNT cold cathode electron optical system with concurrently high beam current and high current density. The microscopic FE characteristics of the CNT film emitter is captured through the development of an empirically derived macroscopic simulation model which is used to provide representative emission performance. Through parametrically optimized macroscale simulations, a five-sheet-beam triode electron gun has been designed, and has been shown to emit up to 95 mA at 3.2 kV. Through careful engineering of the electron gun geometric parameters, a low-voltage compact THz radiation source operating in high-order TM 5 , 1 mode is investigated to improve output power and suppress mode competition. Particle in cell (PIC) simulations show the average output power is 33 W at 0.1 THz, and the beam–wave interaction efficiency is approximately 10%.

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Zhang, Yang, Xinchuan Liu, Liye Zhao, Yuanxun Li, and Zhenjun Li. "Simulation and Optimization of CNTs Cold Cathode Emission Grid Structure." Nanomaterials 13, no. 1 (December 22, 2022): 50. http://dx.doi.org/10.3390/nano13010050.

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Carbon nanotubes (CNTs) show significant advantages in the development of cold cathode X-ray tubes due to their excellent field emission performance; however, there are still some problems, such as short lifetime and the low emission current of large-area CNTs. In this paper, a front-grid carbon nanotube array model was established, and the electric field intensity near the tip of the CNTs’ electric field enhancement factor was analytically calculated. A simulation model of a CNT three-dimensional field emission electron gun was established by using computer simulation technology (CST). The effects of grid wire diameter, grid aperture shape, and the distribution of grid projection on the cathode surface on the cathode current, anode current, and electron transmission efficiency were analyzed. The aperture ratio was used to evaluate the grid performance, and the simulation results show that the ideal aperture ratio should be between 65% and 85%. A grid structure combining a coarse grid and a fine grid was designed, which can make the electric field intensity around the grid evenly distributed, and effectively increased the cathode emission current by 24.2% compared with the structure without the fine grid. The effect of grid aperture ratio on the electron transmission efficiency was tested. The simulation results and optimized structure can provide a reference for the grid design of cold cathode emission X-ray tubes.

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Qistina, Omar, Ali Salmiaton, Thomas S. Y. Choong, Yun Hin Taufiq-Yap, and Shamsul Izhar. "Optimization of Carbon Nanotube-Coated Monolith by Direct Liquid Injection Chemical Vapor Deposition Based on Taguchi Method." Catalysts 10, no. 1 (January 2, 2020): 67. http://dx.doi.org/10.3390/catal10010067.

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Carbon nanotubes (CNTs) have the potential to act as a catalyst support in many sciences and engineering fields due to their outstanding properties. The CNT-coated monolith was synthesized over a highly active Ni catalyst using direct liquid injection chemical vapor deposition (CVD). The aim was to study the optimum condition for synthesizing CNT-coated monoliths. The Taguchi method with L9 (34) orthogonal array design was employed to optimize the experimental conditions of CNT-coated monoliths. The design response was the percentage of carbon yield expressed by the signal-to-noise (S/N) value. The parameters including the mass ratio of Ni to citric acid (Ni:CA) (A), the injection rate of carbon source (B), time of reaction (C), and operating temperature (D) were selected at three levels. The results showed that the optimum conditions for CNT-coated monolith were established at A1B2C1D2 and the most influential parameter was D followed by B, C, and A. The ANOVA analysis showed the design was significant with R-squared and standard deviation of the factorial model equal to 0.9982 and 0.22, respectively. A confirmation test was conducted to confirm the optimum condition with the actual values of the average percentage of carbon yield deviated 1.4% from the predicted ones. The CNT-coated monoliths were characterized by various techniques such as field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Raman spectroscopy.

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Bulyarskiy, Sergey V., Alexander A. Dudin, Alexander V. Lakalin, Andrey P. Orlov, Alexander A. Pavlov, Roman M. Ryazanov, and Artemiy A. Shamanaev. "Effect of heating and resistance on emission properties of carbon nanotubes." Characterization and Application of Nanomaterials 3, no. 2 (November 21, 2020): 49. http://dx.doi.org/10.24294/can.v3i2.567.

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We have studied the effect of the series resistance on the heating of the cathode, which is based on carbon nanotubes and serves to realize the field emission of electrons into the vacuum. The experiment was performed with the single multi-walled carbon nanotube (MCNT) that was separated from the array grown by CVD method with thin-film Ni-Ti catalyst (nickel 4 nm/Ti 10 nm). The heating of the cathode leads to the appearance of a current of the thermionic emission. The experimental voltage current characteristic exhibited the negative resistance region caused by thermal field emission. This current increases strongly with increasing voltage and contributes to the degradation of the cold emitter. The calculation of the temperature of the end of the cathode is made taking into account the effect of the phenomenon that warms up and cools the cathode. We have developed a method for processing of the emission volt-ampere characteristics of a cathode, which relies on a numerical calculation of the field emission current and the comparison of these calculations with experiments. The model of the volt-ampere characteristic takes into account the CNT’s geometry, properties, its contact with the catalyst, heating and simultaneous implementation of the thermionic and field emission. The calculation made it possible to determine a number of important parameters, including the voltage and current of the beginning of thermionic emission, the temperature distribution along the cathode and the resistance of the nanotube. The phenomenon of thermionic emission from CNTs was investigated experimentally and theoretically. The conditions of this type emission occurrence were defined. The results of the study could form the basis of theory of CNT emitter’s degradation.

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Behling, Rolf. "Electric Field Enhancing Artifacts as Precursors for Vacuum High-Voltage Breakdown." Instruments 3, no. 4 (December 17, 2019): 64. http://dx.doi.org/10.3390/instruments3040064.

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Abrupt formation of plasma in a high-voltage insulating vacuum gap and subsequent discharge of electrodes limits the reliability of a class of vacuum electronic devices, such as X-ray tubes. It has been suggested that electron field emission from negatively charged electrodes would precede and initiate such discharge. Heating and evaporation of material upon field emission would cause dense plasma to develop in periods of nanoseconds. High-pressure plasma would expand from the cathode, eventually bridging the gap. Nevertheless, the very reason for the unredictable initial development of discharge events after long periods of reliable operation is still matter of debate. Experience from industrial processes suggests hydrocarbon contamination to degrade the electric stability of high-voltage gaps. While former attempts aimed at explaining high field emission by carbonaceous 2D structures or surface resonance effects, this paper discusses whether 3D structures may grow slowly, until their evaporation in a matter of nanoseconds. Similar to the production of carbon nanotubes, protruding structures might comprise carbon and, in addition, metallic nanoparticles, which would boost production of vapor during their explosion. The hypothesis was tested by scanning electron and energy-dispersive X-ray inspection of two cathodes of medical X-ray tubes, covered with metallic seed nanoparticles, which served as model systems. A third cleaner cathode was inspected for comparison. Although certain suggested conditions of carbon feed, elevated substrate temperature and nanoparticle contamination of the surfaces were met, images showed only a very weak sign of growth of suspicious carbon structures. It seems, therefore, unlikely that CNT-like structures are a major cause of high-voltage breakdown between electrodes of X-ray tubes.

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Hussain, Md Zakir, Sabah Khan, Rajamani Nagarajan, Urfi Khan, and Vishnu Vats. "Fabrication and Microhardness Analysis of MWCNT/MnO2 Nanocomposite." Journal of Materials 2016 (October 10, 2016): 1–10. http://dx.doi.org/10.1155/2016/6070468.

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Recent research has shown that carbon nanotube (CNT) acts as a model reinforcement material for fabricating nanocomposites. The addition of CNT as a reinforcing material into the matrix improves the mechanical, thermal, tribological, and electrical properties. In this research paper multiwalled carbon nanotube (MWCNT), with different weight percentage (5%, 10%, and 15%), was reinforced into manganese dioxide (MnO2) matrix using solution method. The different weight % of MWCNT/MnO2 nanocomposite powders was compacted and then sintered. The phase analysis, morphology, and chemical composition of the nanocomposites were examined by X-ray diffractometer, Field Emission Scanning Electron Microscope (FESEM), and Energy Dispersive X-Ray (EDX), respectively. The XRD analysis indicates the formation of MWCNT/MnO2 nanocomposites. The FESEM surface morphology analysis shows that MnO2 nanotube is densely grown on the surface of MWCNT. Further, microhardness of MWCNT/MnO2 nanocomposite was measured and it was found that 10 wt% has higher microhardness in comparison to 5 and 15 wt%. The microhardness of the composites is influenced by mass density, nanotube weight fraction, arrangement of tubes, and dispersion of MWCNT in H2SO4(aq) solution.

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Більше джерел

Дисертації з теми "CNT MODEL FOR FIELD EMISSION"

Parmee, Richard. "X-ray generation by field emission." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/284924.

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Анотація:

Since the discovery of X-rays over a century ago the techniques applied to the engineering of X-ray sources have remained relatively unchanged. From the inception of thermionic electron sources, which, due to simplicity of fabrication, remain central to almost all X-ray applications at this time, there have been few fundamental technological advances. The emergence of new materials and manufacturing techniques has created an opportunity to replace the traditional thermionic devices with those that incorporate Field Emission electron sources. One of the most important attributes of Field Emission X-ray sources is their controllability, and in particular the fast response time, which opens the door to applying techniques which have formerly been the preserve of optical systems. The work in this thesis attempts to bridge the gap between the fabrication and optimisation of the vacuum electronic devices and image processing aspects of a new approach to high speed radiographic imaging, particularly with a view to addressing practical real-world problems. Off the back of a specific targeted application, the project has involved the design of a viable field emission X-ray source, together with the development of an understanding of the failure modes in such devices, both by analysis and by simulation. This thesis reviews the capabilities and the requirements of X-ray sources, the methods by which nano-materials may be applied to the design of those devices and the improvements and attributes that can be foreseen. I study the image processing methods that can exploit these attributes, and investigate the performance of X-ray sources based upon electron emitters using carbon nanotubes. Modelling of the field emission and electron trajectories of the cathode assemblies has led me to the design of equipment to evaluate and optimise the parameters of an X-ray tube, which I have used to understand the performance that is achievable. Finally, I draw conclusions from this work and outline the next steps to provide the basis for a commercial solution.

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Christy, Larry A. "Field Emission Properties of Carbon Nanotube Fibers and Sheets for a High Current Electron Source." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819279.

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Navitski, Aliaksandr [Verfasser]. "Scanning field emission investigations of structured CNT and MNW cathodes, niobium surfaces and photocathodes / Aliaksandr Navitski." Wuppertal : Universitätsbibliothek Wuppertal, 2010. http://d-nb.info/1009494678/34.

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Srinivasan, Srikant. "A Compact Model for the Coaxially Gated Schottky Barrier Carbon Nanotube Field Effect Transistor." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1161897189.

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Jones, Randolph D. "Circuit model of a low-voltage field emission cathode." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/15631.

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Zhu, Weiming. "Multiscale Model of Heat Dissipation Mechanisms During Field Emission from Carbon Nanotube Fibers." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530880336075941.

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Eberhardt, Oliver, and Thomas Wallmersperger. "Analysis of the mechanical behavior of single wall carbon nanotubes by a modified molecular structural mechanics model incorporating an advanced chemical force field." SPIE, 2018. https://tud.qucosa.de/id/qucosa%3A35173.

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Анотація:

The outstanding properties of carbon nanotubes (CNTs) keep attracting the attention of researchers from different fields. CNTs are promising candidates for applications e.g. in lightweight construction but also in electronics, medicine and many more. The basis for the realization of the manifold applications is a detailed knowledge of the material properties of the carbon nanotubes. In particular for applications in lightweight constructions or in composites, the knowledge of the mechanical behavior of the CNTs is of vital interest. Hence, a lot of effort is put into the experimental and theoretical determination of the mechanical material properties of CNTs. Due to their small size, special techniques have to be applied. In this research, a modified molecular structural mechanics model for the numerical determination of the mechanical behavior of carbon nanotubes is presented. It uses an advanced approach for the geometrical representation of the CNT structure while the covalent bonds in the CNTs are represented by beam elements. Furthermore, the model is specifically designed to overcome major drawbacks in existing molecular structural mechanics models. This includes energetic consistency with the underlying chemical force field. The model is developed further to enable the application of a more advanced chemical force field representation. The developed model is able to predict, inter alia, the lateral and radial stiffness properties of the CNTs. The results for the lateral stiffness are given and discussed in order to emphasize the progress made with the presented approach.

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Dionne, Martin. "Optimized carbon nanotube array cathodes for thermo-field emission in plasmas: a theoretical model and an experimental verification." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97045.

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In this work we developed a 3-D theoretical model for plasma-enhanced thermo-field emission from nanostructured cathodes in the absence of significant erosion. Our first studies indicated that very dense arrays of vertically-aligned carbon nanotubes (CNT) acting as electron emitters in vacuum could sustain the temperatures resulting from very high surface-averaged current densities such as those found in the cathode spots of arc discharges on non-refractory cathodes. A comparative study of the electron emission models for cold surfaces subjected to strong electric field revealed the existence of a simple relation between the inaccurate Fowler-Nordheim (F-N) equation and the accepted result provided by the theory of Murphy and Good (M-G). We therefore proposed a parametric equation for the emitted current density which was as convenient as the F-N equation but more accurate. The use of M-G theory has also provided an explanation for the tip cooling effect described in a previous study on the destruction of field emitting CNT. We identified the source of the tip cooling effect as the Nottingham effect. For very short emitters, this particular effect heats the surface and accelerates the destruction process and for long emitters, it creates a small isothermal zone at the emitter's tip which is destroyed when it reaches a critical temperature (approximately 1850 K according to our calculations). When combined to existing data on the emitter's length, its diameter, the applied voltage and the measured current, our model can provide the emitter's work function, its room temperature resistivity and the value of the thermal contact resistance between the emitter and its substrate. Another version of this model includes a calculation of the surface electric field in the presence of a non-thermal plasma. To this end we modified the model developed by Mackeown and obtained a general result for 3-D surfaces. This general expression requires the calculation of the ion flux enhancement factor which can be obtained by solving Laplace equation above the surface of interest. This simple approach allows us to describe how the ions are redistributed within the sheath towards the tip of the CNT where the surface field increases. These theoretical predictions were tested by developing simultaneously a fabrication process for a composite electrode matching the optimized design we suggested. Anodic aluminum oxide templates were used as substrates to grow CNT arrays. In order to facilitate their large scale use we modified a standard CNT production process to allow the direct use of as anodized commercial aluminum. Our resulting electrodes were then used as cathodes in low pressure gas discharges. The operating parameters of these discharges are different from the typical voltages and current densities found in glow discharges using as electrodes bare aluminum surfaces. In fact, due to the very low work function of the sharp and relatively ordered emission sites and the simultaneous presence of a ceramic template around them, our electrodes produced very diffuse attachment points for the plasma in a similar fashion as thermionic cathodes do for high pressure arcs. They also required lower (38-140 V) sustaining voltages than what is necessary to sustain a conventional glow discharge. Our electrodes also showed the ability to sustain these low voltage discharges for as much as 500 hours if their bulk temperature was maintained below 60 Celsius and if water vapour was added to the feed gas. Our experiments in nitrogen-water mixtures demonstrated the feasibility of producing large amounts of UV photons at an operating voltage (anode, grounded cathode) of 90-100 V. These results are very promising for future applications in lighting.
Dans le cadre de ce projet nous avons développé un modèle en 3-D pour l'émission électronique par effet thermo-champ stimulée par un plasma. Nos premiers résultats ont indiqué que des réseaux denses de nanotubes de carbone (NTC) agissant en tant qu'émetteurs dans le vide pouvaient supporter les températures résultant de densité de courant moyennes très élevées de l'ordre de celles présentes dans les taches cathodiques d'arcs opérant sur des cathodes non-réfractaires. Une étude comparative des modèles pour l'émission électronique pour les surfaces froides soumises à de forts champs électriques a révélé l'existence d'une relation simple entre l'équation imprécise de Fowler-Nordheim (F-N) et le résultat accepté fourni par la théorie de Murphy et Good (M-G). Nous avons donc proposé une équation paramétrique précise et simple pour la densité de courant émise. L'usage de la théorie de M-G a aussi fourni une explication pour l'effet de refroidissement à la pointe décrit dans une étude précédente sur la destruction de NTC émettant par effet de champ: l'effet Nottingham. Pour des émetteurs très courts, cet effet particulier chauffe la surface et accélère le processus de destruction et pour de longs émetteurs, il crée une petite zone isotherme à la pointe de l'émetteur qui est détruite lorsqu'elle atteint une température critique (approximativement 1850 K). Lorsque combiné à des données sur la longueur de l'émetteur, son diamètre, la tension appliquée et le courant mesuré, notre modèle peut fournir le travail de sortie de l'émetteur, sa résistivité à la température ambiante et la valeur de la résistance de contact thermique entre l'émetteur et son substrat. Une autre version de ce modèle inclut un calcul du champ électrique de surface en présence d'un plasma froid. À cette fin, nous avons modifié le modèle développé par Mackeown et obtenu un résultat général pour des surfaces en 3-D. Cette expression générale requiert le calcul du facteur d'amplification du flux ionique, lequel peut être obtenu en résolvant l'équation de Laplace au dessus de la structure d'intérêt. Cette approche simple nous permet de décrire comment les ions sont redistribués à l'intérieur de la gaine vers la pointe des NTC où le champ électrique augmente. Ces prédictions ont été testées en développant simultanément un procédé de fabrication pour une électrode composite correspondant au schéma optimisé que nous suggérions. Des patrons d'oxyde anodique d'aluminium furent utilisés en tant que substrats pour faire croître nos réseaux de NTC mais afin de faciliter leur usage à grande échelle nous avons modifié le procédé de production des NTC pour permettre l'usage directe d'aluminium commercial anodisé. Nos électrodes furent ensuite utilisées comme cathodes dans des décharges à basse pression. Les tensions et densités de courant mesurées sont différentes des valeurs typiques rencontrées dans les décharges électroluminescentes utilisant comme électrodes, des surfaces d'aluminium. En fait, en raison du très faible travail de sortie des sites d'émission pointus et relativement ordonnés et de la présence simultanée d'un patron de céramique autour d'eux, nos électrodes ont produit des points d'attachement très diffus pour le plasma d'une façon similaire à ce qui est observé pour des cathodes réfractaires chaudes telles que le tungstène. Les tensions d'opération, dans la plage 38-140 V, sont de beaucoup inférieures aux tensions observées avec des électrode d'aluminium (>200 V). Nos électrodes ont aussi démontré leur capacité de maintenir ces décharges à basse tension pour au moins 500 heures si leur température moyenne était maintenue sous 60 Celsius et si de la vapeur d'eau était ajoutée au gaz injecté. Nos expériences dans des mélanges d'azote et d'eau ont démontré la faisabilité de produire de larges quantités de photons UV pour un potentiel anodique (cathode mise à la terre) de 90-100 V. Ces résultats sont très prometteurs pour de futures applications en éclairage.

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Abdioskouei, Maryam. "Improving air quality prediction through characterizing the model errors using data from comprehensive field experiments." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6535.

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Uncertainty in the emission estimates is one the main reasons for shortcomings in the Chemistry Transport Models (CTMs) which can reduce the confidence level of impact assessment of anthropogenic activities on air quality and climate. This dissertation focuses on understating the uncertainties within the CTMs and reducing these uncertainties by improving emission estimates The first part of this dissertation focuses on reducing the uncertainties around the emission estimates from oil and Natural Gas (NG) operations by using various observations and high-resolution CTMs. To achieve this goal, we used Weather Research and Forecasting with Chemistry (WRF-Chem) model in conjunction with extensive measurements from two major field campaigns in Colorado. Ethane was used as the indicator of oil and NG emissions to explore the sensitivity of ethane to different physical parametrizations and simulation set-ups in the WRF-Chem model using the U.S. EPA National Emission Inventory (NEI-2011). The sensitivity analysis shows up to 57.3% variability in the modeled ethane normalized mean bias (NMB) across the simulations, which highlights the important role of model configurations on the model performance. Comparison between airborne measurements and the sensitivity simulations shows a model-measurement bias of ethane up to -15ppb (NMB of -80%) in regions close to oil and NG activities. Under-prediction of ethane concentration in all sensitivity runs suggests an actual under-estimation of the oil and NG emissions in the NEI-2011 in Colorado. To reduce the error in the emission inventory, we developed a three-dimensional variational inversion technique. Through this method, optimal scaling factors up to 6 for ethane emission rates were calculated. Overall, the inversion method estimated between 11% to 15% higher ethane emission rates in the Denver-Julesburg basin compared to the NEI-201. This method can be extended to constrain oil and NG emissions in other regions in the US using the available measurement datasets. The second part of the dissertation discusses the University of Iowa high-resolution chemical weather forecast framework using WRF-Chem designed for the Lake Michigan Ozone Study (LMOS-2017). LMOS field campaign took place during summer 2017 to address high ozone episodes in coastal communities surrounding Lake Michigan. The model performance for clouds, on-shore flows, and surface and aircraft sampled ozone and NOx concentrations found that the model successfully captured much of the observed synoptic variability of onshore flows. Selection of High-Resolution Rapid Refresh (HRRR) model as initial and boundary condition, and the Noah land surface model, significantly improved comparison of meteorology variables to both ground-based and aircraft data. Model consistently underestimated the daily maximum concentration of ozone. Emission sensitivity analysis suggests that increase in Hydrocarbon (HC). Variational inversion method and measurements by GeoTAS and TROPOMI instruments and airborne and ground-based measurements can be used to constrain NOx emissions in the region.

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MIZUTANI, Teruyoshi, Tatsuo MORI, Kazue KANEKO, Don-Chan CHO, and Takuya OGAWA. "Study on the Conduction Mechanism of Organic Light-Emitting Diode Using One-Dimensional Discontinuous Model." Institute of Electronics, Information and Communication Engineers, 2002. http://hdl.handle.net/2237/15010.

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Книги з теми "CNT MODEL FOR FIELD EMISSION"

A, Schwartz Richard, and United States. National Aeronautics and Space Administration., eds. Energetic consequences of the DC-electric field model. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Solymar, L., D. Walsh, and R. R. A. Syms. The free electron theory of metals. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198829942.003.0006.

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The model of the free electron theory is presented. The density of states and the Fermi–Dirac distribution function are discussed, leading to the specific heat of the electrons, the work function, thermionic emission, and the Schottky effects. As examples of applications the field-emission microscope and quartz–halogen lamps are discussed. The photoelectric effect and the energy diagrams relating to the junction between two metals are also discussed.

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Carvalho, Régis de. A voz de cabeça na voz de barítono. Editora ARtemis, 2022. http://dx.doi.org/10.37572/edart_100522538.

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This book has a very specific target audience: singers and teachers in the vocal field. As a result of his experience as a singing teacher and researcher, he presents readers with an alternative vocal training model aimed at working the high region of male medium voices. To follow this path, we approached issues such as the main common technical difficulties encountered by baritones, aspects of vocal classification, aspirated vocal parameters and vocal physiology. Finally, we discussed possible signs of effectiveness of using a vocalize model that works with falsetto emission to facilitate access to head register notes in male middle voices.

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Milonni, Peter W. An Introduction to Quantum Optics and Quantum Fluctuations. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780199215614.001.0001.

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This book is an introduction to quantum optics for students who have studied electromagnetism and quantum mechanics at an advanced undergraduate or graduate level. It provides detailed expositions of theory with emphasis on general physical principles. Foundational topics in classical and quantum electrodynamics, including the semiclassical theory of atom-field interactions, the quantization of the electromagnetic field in dispersive and dissipative media, uncertainty relations, and spontaneous emission, are addressed in the first half of the book. The second half begins with a chapter on the Jaynes-Cummings model, dressed states, and some distinctly quantum-mechanical features of atom-field interactions, and includes discussion of entanglement, the no-cloning theorem, von Neumann’s proof concerning hidden variable theories, Bell’s theorem, and tests of Bell inequalities. The last two chapters focus on quantum fluctuations and fluctuation-dissipation relations, beginning with Brownian motion, the Fokker-Planck equation, and classical and quantum Langevin equations. Detailed calculations are presented for the laser linewidth, spontaneous emission noise, photon statistics of linear amplifiers and attenuators, and other phenomena. Van der Waals interactions, Casimir forces, the Lifshitz theory of molecular forces between macroscopic media, and the many-body theory of such forces based on dyadic Green functions are analyzed from the perspective of Langevin noise, vacuum field fluctuations, and zero-point energy. There are numerous historical sidelights throughout the book, and approximately seventy exercises.

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Частини книг з теми "CNT MODEL FOR FIELD EMISSION"

Sinha, N., D. Roy Mahapatra, R. V. N. Melnik, and J. T. W. Yeow. "Computational Implementation of a New Multiphysics Model for Field Emission from CNT Thin Films." In Computational Science – ICCS 2008, 197–206. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-69387-1_22.

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Ohkawa, Yasushi. "CNT Field-Emission Cathode for Space Applications." In Nanostructured Carbon Electron Emitters and Their Applications, 315–30. New York: Jenny Stanford Publishing, 2021. http://dx.doi.org/10.1201/9781003141990-15.

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Glauvitz, Nathan E., Ronald A. Coutu, Peter J. Collins, and LaVern A. Starman. "Etching Silicon Dioxide for CNT Field Emission Device." In MEMS and Nanotechnology, Volume 6, 93–99. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-4436-7_14.

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Saito, Yahachi. "Emission of C+20 by Field Evaporation from CNT." In Nanostructured Carbon Electron Emitters and Their Applications, 343–50. New York: Jenny Stanford Publishing, 2021. http://dx.doi.org/10.1201/9781003141990-17.

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Asaka, Koji, and Yahachi Saito. "Growth of Long Linear Carbon Chains after Serious Field Emission from a CNT Film." In Nanostructured Carbon Electron Emitters and Their Applications, 331–42. New York: Jenny Stanford Publishing, 2021. http://dx.doi.org/10.1201/9781003141990-16.

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Godeferd, Fabien, Lukas Liechtenstein, Claude Cambon, Julian Scott, and Benjamin Favier. "A Model for the Far-Field Anisotropic Acoustic Emission of Rotating Turbulence." In IUTAM Symposium on Computational Physics and New Perspectives in Turbulence, 297–302. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6472-2_46.

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Morrison, Barbara J., and Richard L. Bell. "Emission Estimates for a High Viscosity Crude Oil Surface Impoundment: 1. Field Measurements for Heat Transfer Model Validation." In Intermedia Pollutant Transport, 167–74. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0511-8_11.

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Pourasl, Ali Hosseingholi, Mohammad Taghi Ahmadi, Meisam Rahmani, Razali Ismail, and Michael Loong Pengl Tan. "Graphene and CNT Field Effect Transistors Based Biosensor Models." In Handbook of Research on Nanoelectronic Sensor Modeling and Applications, 294–333. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0736-9.ch012.

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In this chapter, novel ideas of graphene and CNT based electrical biosensors are provided. A liquid gated graphene field effect transistor (LG-GFET) based biosensor model is analytically developed for electrical detection of Escherichia coli (E. coli) bacteria. E. coli absorption effects on the graphene surface in the form of conductance variation is considered. Moreover, the current-voltage characteristic in terms of conductance model is applied to evaluate the performance of the biosensor model. Furthermore, the CNT-FET platform is employed for modeling biosensor in order to detect Glucose. For diagnosing and monitoring the blood glucose level, glucose oxidase (GOx) based enzyme sensors have been immensely used. According to the proposed CNT-FET structure, charge based analytical modeling approach is used. The charge-based carrier velocity model is implemented to study electrical characteristics of CNT-FET. In the presented model, the gate voltage is considered as a function of glucose concentration. Finally, the both of presented models are compared with published experimental data.

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"Chapter 11: Theoretical Model and Methodology." In Quantum Tunneling and Field Electron Emission Theories, 151–55. WORLD SCIENTIFIC, 2013. http://dx.doi.org/10.1142/9789814440226_0011.

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Shabani, Elham, Mohammad Ali Ghorbani, and Samed Inyurt. "The power of the GP-ARX model in CO2 emission forecasting." In Risk, Reliability and Sustainable Remediation in the Field of Civil and Environmental Engineering, 79–91. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-323-85698-0.00013-7.

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Тези доповідей конференцій з теми "CNT MODEL FOR FIELD EMISSION"

Anand, Sandeep V., D. Roy Mahapatra, Niraj Sinha, J. T. W. Yeow, and R. V. N. Melnik. "Field Emission Efficiency of a Carbon Nanotube Array Under Parasitic Nonlinearities." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39558.

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Carbon Nanotubes (CNTs) grown on substrates are potential electron sources in field emission applications. Several studies have reported the use of CNTs in field emission devices, including field emission displays, X-ray tube, electron microscopes, cathode-ray lamps, etc. Also, in recent years, conventional cold field emission cathodes have been realized in micro-fabricated arrays for medical X-ray imaging. CNT-based field emission cathode devices have potential applications in a variety of industrial and medical applications, including cancer treatment. Field emission performance of a single isolated CNT is found to be remarkable, but the situation becomes complex when an array of CNTs is used. At the same time, use of arrays of CNTs is practical and economical. Indeed, such arrays on cathode substrates can be grown easily and their collective dynamics can be utilized in a statistical sense such that the average emission intensity is high enough and the collective dynamics lead to longer emission life. The authors in their previous publications had proposed a novel approach to obtain stabilized field emission current from a stacked CNT array of pointed height distribution. A mesoscopic modeling technique was employed, which took into account electro-mechanical forces in the CNTs, as well as transport of conduction electron coupled with electron–phonon induced heat generation from the CNT tips. The reported analysis of pointed arrangements of the array showed that the current density distribution was greatly localized in the middle of the array, the scatter due to electrodynamic force field was minimized, and the temperature transients were much smaller compared to those in an array with random height distribution. In the present paper we develop a method to compute the emission efficiency of the CNT array in terms of the amount of electrons hitting the anode surface using trajectory calculations. Effects of secondary electron emission and parasitic capacitive nonlinearity on the current-voltage signals are accounted. Field emission efficiency of a stacked CNT array with various pointed height distributions are compared to that of arrays with random and uniform height distributions. Effect of this parasitic nonlinearity on the emission switch-on voltage is estimated by model based simulation and Monte Carlo method.

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Mahmood, Salman, Zainal Arif Burhanudin, and Nor Hisham Hamid. "Effects of CNT density variation in field emission model of ionization gas sensor." In 2011 IEEE Regional Symposium on Micro and Nanoelectronics (RSM). IEEE, 2011. http://dx.doi.org/10.1109/rsm.2011.6088340.

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Yekani Fard, Masoud, Alek Pensky, and Jack Mester. "Nanoscale Interphase Characterization of Agglomerated MWCNT in Composites Connected to Mode I Fracture." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23635.

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Abstract The authors investigate the effect of carbon nanotubes (CNT) on the microstructure, nanomechanical properties, and fracture performance of three-phase polymer matrix composites (PMC). Two types of carbon fiber (CF)-Epoxy-CNT composites with different nanofiller distribution were studied at the nanoscale with PeakForce Quantitative Nanomechanical mapping technique (PFQNM) and macroscale with mode I fracture testing to clarify the relationship between nanofiller interphase properties and mode I fracture performance. CNT agglomerates were identified on the polished sample surface in well-dispersed and agglomerated form. AFM data showed the inhomogeneity of nanoscale local mechanical properties in CNT-rich zones. Variation in material properties is attributed to voids, CNT alignment, and changes in density of the matrix and CNT nanoparticles. A higher resolution AFM scanner and Field Emission Scanning Electron Microscopy are necessary to observe nano-scale interphase mechanical properties and CNT orientation, respectively. Mode I interlaminar fracture testing demonstrated the effectiveness of CNT nanoparticles in preventing crack-jump and fiber-bridging effects. GIC for FCNT is 0.345±0.06 N-mm/mm2 at crack initiation, compared to 0.28±0.03 N-mm/mm2 for the plain epoxy reference sample. CNT nanoparticles increase the energy required for interlaminar fracture by promoting crack deflection and strengthening the interphase between CF and epoxy matrix through increased interfacial surface area.

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Dong, Lixin, Arunkumar Subramanian, and Bradley J. Nelson. "Fabrication and Characterization of NEMS-Based Single Nanotube Emitter Arrays." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80212.

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Arrays of individual carbon nanotube (CNT) emitters for nanoelectromechanical systems (NEMS) are constructed and characterized. Vertically aligned single multi-walled carbon nanotubes (MWNTs) are realized using a combination of e-beam lithography and plasma-enhanced chemical vapour deposition (PECVD) growth. Field emission properties of the arrays are investigated inside a scanning electron microscope (SEM) using scanning anode field emission microscopy (SAFEM) realized from a scanning anode actuated by a 3-DOF nanorobotic manipulator with sub-nanometer resolution. With the SA-FEM and the arrays of single MWNTs, a linear nano encoder is proposed. Vertical position is detected by the change in emission current, whereas the horizontal position of the scanning anode is sensed from the emission distribution. A resolution of 98.3 nm in the vertical direction and 38.0 nm (best: 12.9 nm) in the lateral direction has been achieved. Failure mechanisms of the emitters are systematically investigated in theory and experiment. Failure modes include opening, shortening, breaking, eradicating, and telescoping, which can be identified/monitored with I-V curves and Fowler-Nordheim plots of field emission. Controlled “failures” can find applications in length modification of individual tubes in an array. As an example, selective eradication for fabricating a patterned emitter array is demonstrated. Such techniques will in turn enable applications in NEMS such as field emission based sensor and actuator arrays, nanoelectronics such as wiring or in situ construction of functional elements.

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Lim, Yu Dian, Alexander Avramchuck, Dmitry Grapov, Beng Kang Tay, Sheel Aditya, and Vladimir Labunov. "Field emission characteristics of short CNT bundles." In 2016 IEEE International Vacuum Electronics Conference (IVEC). IEEE, 2016. http://dx.doi.org/10.1109/ivec.2016.7561783.

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Jian Zhang, Yangyang Zhao, Yongjun Cheng, Detian Li, and Changkun Dong. "CNT field emission based ultra-high vacuum measurements." In 2015 28th International Vacuum Nanoelectronics Conference (IVNC). IEEE, 2015. http://dx.doi.org/10.1109/ivnc.2015.7225574.

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Yang, Zhan, Masahiro Nakajima, Yajing Shen, Pengbo Wang, Changhai Ru, Yahua Zhang, Lining Sun, and Toshio Fukuda. "Test of A CNT gyroscope based on field emission." In 2013 IEEE 7th International Conference on Nano/Molecular Medicine and Engnieering (NANOMED). IEEE, 2013. http://dx.doi.org/10.1109/nanomed.2013.6766316.

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Stępińska, Izabela, Halina Wronka, Stanisław Waszuk, Joanna Radomska, Mirosław Kozłowski, Elżbieta Czerwosz, and Florea Craciunoiu. "Field emission from CNT films deposited on porous Si." In XXXVI Symposium on Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments (Wilga 2015), edited by Ryszard S. Romaniuk. SPIE, 2015. http://dx.doi.org/10.1117/12.2205844.

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Liu, Weihua, and Changchun Zhu. "Field Emission Aging Characteristic of Screen Printed CNT Cathode." In 2006 19th International Vacuum Nanoelectronics Conference. IEEE, 2006. http://dx.doi.org/10.1109/ivnc.2006.335480.

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Han, Jun Soo, Ki Nam Yun, Sang Heon Lee, Han Bin Go, Cheol Jin Lee, and Yoon-Ho Song. "Field emission properties of triode structure CNT film emitter." In 2017 30th International Vacuum Nanoelectronics Conference (IVNC). IEEE, 2017. http://dx.doi.org/10.1109/ivnc.2017.8051593.

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Звіти організацій з теми "CNT MODEL FOR FIELD EMISSION"

Boyarski, A. Model of High Current Breakdown from Cathode Field Emission in Aged Wire Chambers. Office of Scientific and Technical Information (OSTI), February 2004. http://dx.doi.org/10.2172/826767.

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Stulen. L51628 A Transient Far-Field Model of the Acoustic Emission in Buried Pipelines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 1986. http://dx.doi.org/10.55274/r0011317.

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This report describes the development of an analytical model to generate synthetic acoustic emission (AE) propagating in a buried gas transmission pipeline in response to a source. The sources are assumed to be transient forces acting at a point in the pipe wall. The solution of the model is the set of displacements at a given location relative to the point source. These displacements are the representations of the AE waveforms.

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Sancar, Selcuk, and Foster Stulen. L51501 Field Verification of Optimum Transducer Design Criteria for Acoustic Emission Monitoring. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 1986. http://dx.doi.org/10.55274/r0011429.

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This work acquired and analyzed simulated acoustic emissions waveforms from pipelines in three series of field tests. The purposes of the analyses were to verify the accuracy of an analytical model of acoustic emission propagation in pipelines to determine transducer design/selection criteria, and to further evaluate the sensitivity of the verification system. Two sets of tests were performed on a bare and a coated 70-ft. long section of pipe. The third test was performed in conjunction with a hydrotest of a new line being installed near Clay City, Kentucky.

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Olsen and Willson. L51916 Pressure Based Parametric Emission Monitoring Systems (PEMS). Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2002. http://dx.doi.org/10.55274/r0010181.

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The natural gas industry operates over 8000 stationary large bore (bore greater than 14 in) natural gas engines for natural gas compression on pipelines and power generation. As emissions regulations become increasingly more stringent, the need for low cost methods for compliance demonstration arises. A PEMS model is one such approach. Research in this area has increased significantly during the last decade. PEMS models for this application utilize parameters commonly measured on industrial engines in the field to predict engine-out emissions. Monitoring emissions in this manner represents a significant cost savings over the periodic use of chemiluminescence NOX analyzers, which are not standard equipment in natural gas compressor stations. PEMS model accuracy is dependent on the quality of the input data, both the training NOX measurements and the selection of input parameters. Hence, it is important to have both reliable data measurement methods and an understanding of engine operating parameters relation to NOX. This work is part of the body of work referred to as the Integrated Test Plan (ITP), performed at the Engines and Energy Conversion Laboratory (EECL). This report details an investigation into Parametric Emissions Monitoring System (PEMS) models. It is the final document to be delivered under the ITP program. Much of the work performed under the ITP program focused on Hazardous Air Pollutants (HAPs) research. However, the emphasis of the PEMS work is on the prediction of oxides of nitrogen (NOX) emissions from large bore natural gas engines. In this work two different PEMS models are developed, a semi-empirical model and a neural network model. The semi-empirical model is based on general relationships between NOX emissions and engine parameters, but contains empirical constants that are determined based on the best fit to engine experimental data. The neural network model utilizes a similar set of input parameters, but relies on the neural network code to determine the relationships between input parameters and measured NOX emissions. The neural network model also contains empirical constants. The mathematics involved in both models is described. A single term semi-empirical model, which has been utilized in the literature as a PEMS model, is applied for comparative purposes.

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Ziegler, Nancy, Nicholas Webb, Adrian Chappell, and Sandra LeGrand. Scale invariance of albedo-based wind friction velocity. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40499.

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Obtaining reliable estimates of aerodynamic roughness is necessary to interpret and accurately predict aeolian sediment transport dynamics. However, inherent uncertainties in field measurements and models of surface aerodynamic properties continue to undermine aeolian research, monitoring, and dust modeling. A new relation between aerodynamic shelter and land surface shadow has been established at the wind tunnel scale, enabling the potential for estimates of wind erosion and dust emission to be obtained across scales from albedo data. Here, we compare estimates of wind friction velocity (u*) derived from traditional methods (wind speed profiles) with those derived from the albedo model at two separate scales using bare soil patch (via net radiometers) and landscape (via MODIS 500 m) datasets. Results show that profile-derived estimates of u* are highly variable in anisotropic surface roughness due to changes in wind direction and fetch. Wind speed profiles poorly estimate soil surface (bed) wind friction velocities necessary for aeolian sediment transport research and modeling. Albedo-based estimates of u* at both scales have small variability because the estimate is integrated over a defined, fixed area and resolves the partition of wind momentum be-tween roughness elements and the soil surface. We demonstrate that the wind tunnel-based calibration of albedo for predicting wind friction velocities at the soil surface (us*) is applicable across scales. The albedo-based approach enables consistent and reliable drag partition correction across scales for model and field estimates of us* necessary for wind erosion and dust emission modeling.

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Peterson, Warren. PR-663-20208-Z02 CO2e Economic Analysis Tool. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), November 2021. http://dx.doi.org/10.55274/r0012191.

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The CO2e Economic Analysis Tool (CEAT) is a spreadsheet-based application for comparing project alternatives that are sensitive to GHG emission rates, emission levies, or other financial parameters. The tool is applicable to hydrocarbon transportation systems, with an emphasis on natural gas transmission. CEAT provides a comparative forecast of benefits and expenses (including levies) from initial cash flow to arrival at the forecast horizon. Along with financial forecasting functions, the tool estimates the emissions associated with a wide range of hydrocarbon fluids (gas and liquid), electricity, thermal energy, and upstream transportation. The forecast model provides a flexible configuration of CAPEX and O and M expenses and a customizable levy structure. This updated version of the tool includes enhancements based on feedback from the first edition such as greater control of fuel use patterns. It also includes pre-designed, easily customizable analysis templates for situations that are likely to be repeated often in the field. The tool is Excel-based and requires version 16 or newer. This download includes a copy of the report and a copy of the Excel-based Check Mate software (aka Checkmate). The spreadsheet and the associated report are licensed to single users as noted in the end-user license agreement that is contained in the zip file.

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Bajwa, Abdullah, and Timothy Jacobs. PR-457-17201-R01 Residual Gas Fraction Estimation Based on Measured In-Cylinder Pressure. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2018. http://dx.doi.org/10.55274/r0011519.

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Developing a reliable means of predicting and controlling engine operation at various operating conditions may be a reasonable pathway for meeting increasingly stringent engine emission regulations. In order to do so, estimates of the mixture composition at the end of the gas exchange process (i.e. at exhaust port closure, or EPC) are helpful for having accurate models of engine combustion. A substantial fraction of the trapped charge mixture is composed of residual gases from previous cycles. This fraction, the trapped residual fraction, changes combustion characteristics of the trapped mixture. Residual gases dilute the fresh charge, thus decreasing the flame speed and temperature. Moreover, because of their spatial inhomogeneity, especially around the spark plug, these gases seem to have implications for engine stability. All these factors likely affect engine performance and emissions. Unfortunately, it is not practical to directly measure the trapped residual fraction for engines operating in the field. To overcome this, computational models can be developed for control applications which estimate this fraction based on some measurable engine parameters e.g. manifold pressures, temperatures, etc. Currently, such models aren't readily available for stationary two-stroke natural-gas engines. This report summarizes the results of phase I of a multi-phase project. In this phase a GT-Power based model was developed for an Ajax E-565 single-cylinder engine to study various factors that influence the removal, or lack thereof, of residual gases from the engine cylinder. The model was used to successfully simulate various engine operating conditions and study the scavenging characteristics of the engine. Various steps followed in the development of the model have been discussed in the report, and at the end some preliminary results and recommendations for the next phase of the project have been presented.

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