Journal articles: 'Molecular and optical physics not elsewhere classified'

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Kelly, Matthew, and Yuriy Kuleshov. "Flood Hazard Assessment and Mapping: A Case Study from Australia’s Hawkesbury-Nepean Catchment." Sensors 22, no. 16 (August 19, 2022): 6251. http://dx.doi.org/10.3390/s22166251.

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Floods are among the costliest natural hazards, in Australia and globally. In this study, we used an indicator-based method to assess flood hazard risk in Australia’s Hawkesbury-Nepean catchment (HNC). Australian flood risk assessments are typically spatially constrained through the common use of resource-intensive flood modelling. The large spatial scale of this study area is the primary element of novelty in this research. The indicators of maximum 3-day precipitation (M3DP), distance to river—elevation weighted (DREW), and soil moisture (SM) were used to create the final Flood Hazard Index (FHI). The 17–26 March 2021 flood event in the HNC was used as a case study. It was found that almost 85% of the HNC was classified by the FHI at ‘severe’ or ‘extreme’ level, illustrating the extremity of the studied event. The urbanised floodplain area in the central-east of the HNC had the highest FHI values. Conversely, regions along the western border of the catchment had the lowest flood hazard risk. The DREW indicator strongly correlated with the FHI. The M3DP indicator displayed strong trends of extreme rainfall totals increasing towards the eastern catchment border. The SM indicator was highly variable, but featured extreme values in conservation areas of the HNC. This study introduces a method of large-scale proxy flood hazard assessment that is novel in an Australian context. A proof-of-concept methodology of flood hazard assessment developed for the HNC is replicable and could be applied to other flood-prone areas elsewhere.

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Huang, Hongxin. "Classified one‐step modified signed‐digit arithmetic and its optical implementation." Optical Engineering 35, no. 4 (April 1, 1996): 1134. http://dx.doi.org/10.1117/1.600602.

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Khalid, Hagar, Roy Schwartz, Luke Nicholson, Josef Huemer, Mohamed Hosny El-Bradey, Dawn A. Sim, Praveen J. Patel, et al. "Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy." British Journal of Ophthalmology 105, no. 1 (March 19, 2020): 118–23. http://dx.doi.org/10.1136/bjophthalmol-2019-315365.

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PurposeTo evaluate the utility of widefield optical coherence tomography angiography (WF-OCTA) compared with clinical examination in grading diabetic retinopathy in patients diagnosed clinically with proliferative diabetic retinopathy (PDR) or severe non-proliferative diabetic retinopathy (NPDR).DesignThis retrospective observational case series included patients diagnosed clinically with PDR or severe NPDR. Patients underwent standard clinical examination and WF-OCTA imaging (PLEX Elite 9000, Carl Zeiss Meditec AG) using 12×12 montage scans between August 2018 and January 2019. Two trained graders identified neovascularisation at the disc (NVD) and neovascularisation elsewhere (NVE) on WF-OCTA which were compared with the clinical examination, and to ultra-widefield fluorescein angiography (UWFA) when available.ResultsSeventy-nine eyes of 46 patients were evaluated. Of those, 57 eyes were diagnosed clinically with PDR, and 22 with severe NPDR. NVD was detected on OCTA-B scan as preretinal hyperreflective material (PRHM) in 39 eyes (100%) with evident flow signals in 79.5% compared with 51.3% detected clinically. We further classified NVD on OCTA into four subtypes and found that subtypes 1 and 2 could not be seen on clinical examination alone. WF-OCTA detected NVE in 81% of the cases compared with 55.7% detected clinically. Using WF-OCTA resulted in a higher percentage of PDR grading (88.6%) than on clinical examination (72.2%). When available, UWFA confirmed the WF-OCTA diagnosis in the majority of cases.ConclusionThis study demonstrates that WF-OCTA has a higher detection rate of PDR than clinical examination. This suggests that this modality could be used non-invasively for the purpose of early detection and characterisation of neovascularisation.

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Romanov, S. G. "3-Dimensional Photonic Crystals at Optical Wavelengths." Journal of Nonlinear Optical Physics & Materials 07, no. 02 (June 1998): 181–200. http://dx.doi.org/10.1142/s0218863598000168.

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Different experimental strategies towards the 3-dimensional photonic crystals operating at optical wavelength are classified. The detailed discussion is devoted to the recent progress in photonic crystals fabricated by template method — the photonic band gap materials on the base of opal. The control of photonic properties of opal-based gratings is achieved through impregnating the opal with high refractive index semiconductors and dielectrics. Experimental study demonstrated the dependence of the stop band behaviour upon the type of impregnation (complete or partial) and showed a way for approaching complete photonic band gap. The photoluminescence from opal- semiconductor gratings revealed suppression of spontaneous emission in the gap region with following enhancement of the emission efficiency at the low-energy edge of the gap.

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RAMELAN, A. H., I. YAHYA, PRASODJO, and E. M. GOLDYS. "GaSb/AlGaSb COMPOUND SEMICONDUCTORS GROWN BY MOCVD FOR OPTOELECTRONIC APPLICATIONS." Journal of Nonlinear Optical Physics & Materials 15, no. 03 (September 2006): 323–29. http://dx.doi.org/10.1142/s0218863506003335.

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Al x Ga 1-x Sb films in the regime 0 ≤ x ≤ 0.30 have been grown by metalorganic chemical vapor deposition on GaAs and GaSb substrates using TMAl , TMGa and TMSb precursors. We report the effects of growth conditions on the optical properties. Samples grown at temperatures of 540°C, 580°C and 600°C and a V/III ratio of 1 have been investigated. The Al x Ga 1-x Sb layers grown at 580°C and 600°C with a V/III ratio of 1 and Al content in the range of 0.5% to 25% were found to exhibit excellent optical quality with a very high optical transmission at energies below the bandgap. The principle photoluminescence features observed are attributed to bound exciton and donor-acceptor transitions with FWHM comparable to the best values reported elsewhere.

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Singh, Pallavi, Devendra Kr Tripathi, Shikha Jaiswal, and H. K. Dixit. "All-Optical Logic Gates: Designs, Classification, and Comparison." Advances in Optical Technologies 2014 (March 19, 2014): 1–13. http://dx.doi.org/10.1155/2014/275083.

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The paper reviews the current status and designs of all-optical gates. Various schemes with and without semiconductor optical amplifiers are discussed and compared. The optical gates are classified according to their design structures. It is divided into two major divisions that is, nonsemiconductor optical amplifier based gates and semiconductor optical amplifier based gates. In nonsemiconductor optical amplifier based gates, different schemes have been proposed to create non-linearity which is discussed. The semiconductor optical amplifier based gates of different design structures are discussed to show the probe pulse that is modulated in different ways to obtain results.

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Amarie, Dragos, Nazanin Mosavian, Elijah L. Waters, and Dwayne G. Stupack. "Underlying Subwavelength Aperture Architecture Drives the Optical Properties of Microcavity Surface Plasmon Resonance Sensors." Sensors 20, no. 17 (August 30, 2020): 4906. http://dx.doi.org/10.3390/s20174906.

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Microcavity surface plasmon resonance sensors (MSPRSs) develop out of the classic surface plasmon resonance technologies and aim at producing novel lab-on-a-chip devices. MSPRSs generate a series of spectral resonances sensitive to minute changes in the refractive index. Related sensitivity studies and biosensing applications are published elsewhere. The goal of this work is to test the hypothesis that MSPRS resonances are standing surface plasmon waves excited at the surface of the sensor that decay back into propagating photons. Their optical properties (mean wavelength, peak width, and peak intensity) appear highly dependent on the internal morphology of the sensor and the underlying subwavelength aperture architecture in particular. Numerous optical experiments were designed to investigate trends that confirm this hypothesis. An extensive study of prior works was supportive of our findings and interpretations. A complete understanding of those mechanisms and parameters driving the formations of the MSPRS resonances would allow further improvement in sensor sensitivity, reliability, and manufacturability.

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Wei, Shan, Yajun Pang, Zhenxu Bai, Yulei Wang, and Zhiwei Lu. "Research Progress of Stress Measurement Technologies for Optical Elements." International Journal of Optics 2021 (April 20, 2021): 1–11. http://dx.doi.org/10.1155/2021/5541358.

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It is of great significance to measure the residual stress distribution accurately for optical elements and evaluate its influence on the performance of optical instruments in optical imaging, aviation remote sensing, semiconductor manufacturing, and other fields. The stress of optical elements can be closely related to birefringence based on photoelasticity. Thus, the method of quantifying birefringence to obtain the stress becomes the main method of stress measurement technologies for optical elements. This paper first introduces the basic principle of stress measurement based on photoelasticity. Then, the research progress of stress measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method. Meanwhile, the advantages and disadvantages of various stress measurement technologies are analyzed and compared. Finally, the developing trend of stress measurement technologies for optical elements is summarized and prospected.

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Moretta, Rosalba, Luca De Stefano, Monica Terracciano, and Ilaria Rea. "Porous Silicon Optical Devices: Recent Advances in Biosensing Applications." Sensors 21, no. 4 (February 13, 2021): 1336. http://dx.doi.org/10.3390/s21041336.

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This review summarizes the leading advancements in porous silicon (PSi) optical-biosensors, achieved over the past five years. The cost-effective fabrication process, the high internal surface area, the tunable pore size, and the photonic properties made the PSi an appealing transducing substrate for biosensing purposes, with applications in different research fields. Different optical PSi biosensors are reviewed and classified into four classes, based on the different biorecognition elements immobilized on the surface of the transducing material. The PL signal modulation and the effective refractive index changes of the porous matrix are the main optical transduction mechanisms discussed herein. The approaches that are commonly employed to chemically stabilize and functionalize the PSi surface are described.

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Hecht, Jeff. "The First Time the Laser Was Classified." Optics and Photonics News 33, no. 1 (January 1, 2022): 40. http://dx.doi.org/10.1364/opn.33.1.000040.

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Lyu, Shuhan, Zheyu Wu, Xinghua Shi, and Qian Wu. "Optical Fiber Biosensors for Protein Detection: A Review." Photonics 9, no. 12 (December 15, 2022): 987. http://dx.doi.org/10.3390/photonics9120987.

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Proteins play an important role in organisms. The fast and high-accuracy detection of proteins is demanded in various fields, such as healthcare, food safty, and biosecurity, especially in the background of the globally raging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Optical fiber sensors have great potential for protein detection due to the excellent characteristics of high sensitivity, miniaturization, and capability for remote monitoring. Over the past decades, a large number of structures have been investigated and proposed. This paper begins with an overview of different fiber sensing structures for protein detection according to the fundamental sensing mechanisms. The overview is classified into four sections, including intensity-modulation, phase-modulation, scattering, and fluorescence. In each section, we reviewed the recent advances of fiber protein sensors and compared their performance, such as sensitivity and limit of detection. And then we analyzed the advantages and disadvantages of the four kinds of biosensors. Finally, the paper concludes with the challenges faced and possible future development of optical fiber protein biosensors for further study.

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Sato, Naoki. "Characteristic electronic structures of organic solids classified in terms of molecular electronic relaxation." Synthetic Metals 64, no. 2-3 (June 1994): 133–39. http://dx.doi.org/10.1016/0379-6779(94)90104-x.

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Liu, Fei, Pingli Han, Yi Wang, Xuan Li, Lu Bai, and Xiaopeng Shao. "Super resolution reconstruction of infrared images based on classified dictionary learning." Infrared Physics & Technology 90 (May 2018): 146–55. http://dx.doi.org/10.1016/j.infrared.2018.03.008.

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KOVÁŘ, JIŘÍ, and ZDENĚK STUCHLÍK. "FORCES IN KERR SPACE–TIMES WITH A REPULSIVE COSMOLOGICAL CONSTANT." International Journal of Modern Physics A 21, no. 23n24 (September 30, 2006): 4869–97. http://dx.doi.org/10.1142/s0217751x06032435.

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Forces defined in the framework of optical reference geometry are introduced in the case of stationary and axially symmetric Kerr black hole and naked-singularity space–times with a repulsive cosmological constant. Properties of the forces acting on test particles moving along circular orbits in the equatorial plane are discussed, whereas it is shown where the gravitational force vanishes and changes its orientation and where the centrifugal force vanishes and changes its orientation independently of the velocity of test particles related to the optical geometry; the Coriolis force does not vanish for the velocity being nonzero. The space–times are classified according to the number of circular orbits where the gravitational and centrifugal forces vanish.

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Ritt, Gunnar, Bastian Schwarz, and Bernd Eberle. "Estimation of Lens Stray Light with Regard to the Incapacitation of Imaging Sensors." Sensors 20, no. 21 (November 5, 2020): 6308. http://dx.doi.org/10.3390/s20216308.

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We present our efforts on estimating light scattering characteristics from commercial off-the-shelf (COTS) camera lenses in order to deduce thereof a set of generic scattering parameters valid for a specific lens class (double Gauss lenses). In previous investigations, we developed a simplified theoretical light scattering model to estimate the irradiance distribution in the focal plane of a camera lens. This theoretical model is based on a 3-parameter bidirectional scattering distribution function (BSDF), which describes light scattering from rough surfaces of the optical elements. Ordinarily, the three scatter parameters of the BSDF are not known for COTS camera lenses, which makes it necessary to assess them by own experiments. Besides the experimental setup and the measurement process, we present in detail the subsequent data exploitation. From measurements on seven COTS camera lenses, we deduced a generic set of scatter parameters. For a deeper analysis, the results of our measurements have also been compared with the output of an optical engineering software. Together with our theoretical model, now stray light calculations can be accomplished even then, when specific scatter parameters are not available from elsewhere. In addition, the light scattering analyses also allow considering the glare vulnerability of optical systems in terms of laser safety.

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Jäger, Matthias C., Jörg Eberhardt, and Douglas W. Cunningham. "Experimental Analysis of Commercial Optical Methods for Foot Measurement." Sensors 22, no. 14 (July 21, 2022): 5438. http://dx.doi.org/10.3390/s22145438.

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Due to the increasing trend of online shopping, shoes are more and more often bought without being tried on. This leads to a strong increase in returns, which results in a high financial as well as ecological burden. To prevent this, feet can be measured either in the store or at home by various systems to determine the exact dimensions of the foot and derive an optimal shoe size. In this paper, we want to present an overview of the methods currently available on the market for the measurement of feet. The most important commercial systems are classified according to the underlying basic technology. Subsequently, the most promising methods were implemented and tested. The results of the different methods were finally compared to find out the strengths and weaknesses of each technology. After determining the measurement accuracy of the length and width for each measurement method and also comparing the general shape of the 3D reconstruction with the GT, it can be said that the measurement using a ToF sensor is currently the most robust, the easiest and, among other methods, the most accurate method.

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Zhang, Pengfei, Le Liu, Yi Tao, Qiang Huang, Heng Shi, Chan Du, Xihui Zhang, and Yonghong He. "An amplitude modulation fluorometric method for phytoplankton classified measure." Optik 125, no. 11 (June 2014): 2661–64. http://dx.doi.org/10.1016/j.ijleo.2013.11.020.

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Memon, Sanober Farheen, Ruoning Wang, Bob Strunz, Bhawani Shankar Chowdhry, J. Tony Pembroke, and Elfed Lewis. "A Review of Optical Fibre Ethanol Sensors: Current State and Future Prospects." Sensors 22, no. 3 (January 26, 2022): 950. http://dx.doi.org/10.3390/s22030950.

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A range of optical fibre-based sensors for the measurement of ethanol, primarily in aqueous solution, have been developed and are reviewed here. The sensing approaches can be classified into four groups according to the measurement techniques used, namely absorption (or absorbance), external interferometric, internal fibre grating and plasmonic sensing. The sensors within these groupings can be compared in terms of their characteristic performance indicators, which include sensitivity, resolution and measurement range. Here, particular attention is paid to the potential application areas of these sensors as ethanol production is globally viewed as an important industrial activity. Potential industrial applications are highlighted in the context of the emergence of the internet of things (IoT), which is driving widespread utilization of these sensors in the commercially significant industrial and medical sectors. The review concludes with a summary of the current status and future prospects of optical fibre ethanol sensors for industrial use.

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Расулов, В. Р., Р. Я. Расулов, Б. Б. Ахмедов, and И. А. Муминов. "Межзонный двухфотонный линейно-циркулярный дихроизм в полупроводниках в приближении Кейна." Физика и техника полупроводников 56, no. 1 (2022): 61. http://dx.doi.org/10.21883/ftp.2022.01.51813.9719.

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Interband two-photon optical transitions are classified and expressions are obtained for the matrix elements in a narrow-gap semiconductor depending on the band parameters, degree of polarization, and light frequency. It is shown that the main contribution to two-photon linear-circular dichroism in narrow-gap semiconductors is made by optical transitions proceeding from the subband of light holes to the conduction band. The dependences of the partial coefficients of interband two-photon absorption of light, which differ from each other by the types of optical transitions, are analyzed depending on the degree of polarization of the light, and a quantitative analysis of the coefficient of linear-circular dichroism of two-photon absorption of light is carried out. Expressions are obtained for the spectral dependence of the coefficient of interband two-photon absorption of light in narrow-gap semiconductors in the Kane model.

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Chen, Yunhao, Li Zhao, Shuai Hao, and Jianing Tang. "Advanced Fiber Sensors Based on the Vernier Effect." Sensors 22, no. 7 (March 31, 2022): 2694. http://dx.doi.org/10.3390/s22072694.

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For decades, optical fiber interferometers have been extensively studied and applied for their inherent advantages. With the rapid development of science and technology, fiber sensors with higher detection sensitivity are needed on many occasions. As an effective way to improve measurement sensitivity, Vernier effect fiber sensors have drawn great attention during the last decade. Similar to the Vernier caliper, the optical Vernier effect uses one interferometer as a fixed part of the Vernier scale and the other as a sliding part of the Vernier scale. This paper first illustrates the principle of the optical Vernier effect, then different configurations used to produce the Vernier effect are classified and discussed. Finally, the outlook for Vernier effect fiber sensors is presented.

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Macdonald, Fraser L. A., Nathan F. Lepora, Jörg Conradt, and Benjamin Ward-Cherrier. "Neuromorphic Tactile Edge Orientation Classification in an Unsupervised Spiking Neural Network." Sensors 22, no. 18 (September 15, 2022): 6998. http://dx.doi.org/10.3390/s22186998.

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Dexterous manipulation in robotic hands relies on an accurate sense of artificial touch. Here we investigate neuromorphic tactile sensation with an event-based optical tactile sensor combined with spiking neural networks for edge orientation detection. The sensor incorporates an event-based vision system (mini-eDVS) into a low-form factor artificial fingertip (the NeuroTac). The processing of tactile information is performed through a Spiking Neural Network with unsupervised Spike-Timing-Dependent Plasticity (STDP) learning, and the resultant output is classified with a 3-nearest neighbours classifier. Edge orientations were classified in 10-degree increments while tapping vertically downward and sliding horizontally across the edge. In both cases, we demonstrate that the sensor is able to reliably detect edge orientation, and could lead to accurate, bio-inspired, tactile processing in robotics and prosthetics applications.

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Novotný, Vít, Petr Sysel, Aleš Prokeš, Pavel Hanák, Karel Slavíček, and Jiří Přinosil. "Fiber Optic Based Distributed Mechanical Vibration Sensing." Sensors 21, no. 14 (July 13, 2021): 4779. http://dx.doi.org/10.3390/s21144779.

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The distributed long-range sensing system, using the standard telecommunication single-mode optical fiber for the distributed sensing of mechanical vibrations, is described. Various events generating vibrations, such as a walking or running person, moving car, train, and many other vibration sources, can be detected, localized, and classified. The sensor is based on phase-sensitive optical time-domain reflectometry (ϕ-OTDR). Related sensing system components were designed and constructed, and the system was tested both in the laboratory and in the real deployment, with an 88 km telecom optical link, and the results are presented in this paper. A two-fiber sensor unit, with a double-sensing range was also designed, and its scheme is described. The unit was constructed and the initial measurement results are presented.

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Bratchenko, Ivan, Yulia Khristoforova, Lyudmila Bratchenko, Alexander Moryatov, Sergey Kozlov, Ekaterina Borisova, and Valery Zakharov. "Optical Biopsy of Amelanotic Melanoma with Raman and Autofluorescence Spectra Stimulated by 785 nm Laser Excitation." Journal of Biomedical Photonics & Engineering 7, no. 2 (June 30, 2021): 020308. http://dx.doi.org/10.18287/jbpe21.07.020308.

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In this work, Raman and autofluorescence spectroscopy in the near-infrared region has been used for examining amelanotic melanoma as the most dangerous type of malignant melanoma. There were 9 patients with amelanotic melanoma, 60 with pigmented melanoma and 120 with basal cell carcinoma enrolled in this study. We studied 9 amelanotic melanoma cases to differentiate them from basal cell carcinoma (n = 120) and pigmented malignant melanoma (n = 60) using portable spectroscopy setup with laser excitation source at 785 nm and low-cost spectrometer. The spectra of the different tumor type were classified using projection on the latent structure analysis with 10-Fold cross-validation. The results of the tumor classification were presented using box-plot diagrams and ROC analysis. We obtained 0.53 and 0.88 ROC AUCs for distinguishing amelanotic melanoma versus (1) pigmented melanoma and (2) basal cell carcinoma respectively based on the joint autofluorescence and Raman spectroscopy analysis that allowed one to diagnose amelanotic melanoma as true melanoma but no basal cell carcinoma.

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Farzaneh, Farnoosh, Reza Faghih Mirzaee, and Keivan Navi. "Novel implementation of 3D multiplexers in nano magnetic logic technology." Microelectronics International 37, no. 4 (July 20, 2020): 173–79. http://dx.doi.org/10.1108/mi-06-2020-0036.

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Purpose Owing to recent challenges of CMOS manufacturing and power consumption in silicon technologies among alternative technologies, Nanomagnetic logic (NML) is one of the most promising technologies, so it was selected for this study. NML is non-volatile with ultra-low power dissipation that operates at room temperature. This paper aims to propose novel implementation of 2% and 4% multiplexers (MUXs) in NML technology. Design/methodology/approach The proposed multiplexers in NML technology are verified by HDL-based simulators. In addition, this study estimated area and power dissipation of the proposed design to compare and approve the promising improvements in comparison to other similar NML implementations. Findings The results show the remarkable improvements in terms of APDP term in comparison to the recent proposed MUXs in NML technology which are reported in Table 2. The proposed implementation of the MUX in NML is designed in three-dimensional layout to improve interconnection complexity which is an integration challenge. Also, by facilitating the routing signals and total wire length needed for clock signals, the negative impact of the power dissipated in clock wires is improved. Originality/value These findings would appeal to a broad audience, such as the readership of Microelectronics International Journal. The authors confirm that this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere. All authors have approved the paper and agreed with submission to Microelectronics International Journal. The authors have read and have abided by the statement of ethical standards for manuscripts submitted to Microelectronics International Journal. The authors have no conflict of interest to declare.

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Cornejo, H. Sanchez, L. De Los Santos Valladares, C. H. W. Barnes, N. O. Moreno, and A. Bustamante Domínguez. "Texture and magnetic anisotropy of YBa2Cu3O7-x film on MgO substrate." Journal of Materials Science: Materials in Electronics 31, no. 23 (October 19, 2020): 21108–17. http://dx.doi.org/10.1007/s10854-020-04623-w.

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AbstractThe texture and magnetic anisotropy of a YBa2Cu3O7-x (YBCO) film growth onto a MgO substrate are analyzed in order to understand the relation between them. X-ray diffraction shows the presence of the (00l) reflections from the YBCO layer with a grain’s fraction value 98%. Rocking Curves (RC) measurements reveal an out-of-plane texture with a full width at the half maximum of 0.81°, revealing a high uniaxial texture in the YBCO film. The temperature dependence of the susceptibility measurements obtained under many applied fields along Hext ||c-axis and Hext||ab-plane reveals strong relationship between the uniaxial texture and the magnetic anisotropy, confirming the high ordering of the CuO2 superconducting planes. In addition, the critical current density values are obtained from the hysteresis loops and compared to similar YBCO films with uniaxial and biaxial texture reported elsewhere.

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Mahim, Z., N. A. Ismail, Mohd Arif Anuar Mohd Salleh, and C. Y. Khor. "The Effect of Temperature on Tin Whisker Growth under Mechanical Stress." Solid State Phenomena 280 (August 2018): 194–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.194.

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The whisker phenomenon has caused the reliability issues which induce short circuit in the electronic manufacturing industries. The research is conducted to study on the formation of pure tin whisker under the control of stress and temperature with the application of mechanical indentation and the formation of whisker can be classified into distinct shape accordingly. The specified ranges of stress and surrounding temperature are set up accordingly to promote the whisker mechanism of pure tin whisker. The pure tin whisker formed is examined in term of morphology characterization via Optical Microscope and Scanning Electron Microscope to analyze on the effect of stress and temperature on the growth morphology of pure tin whisker. This report outlines the research in progress on the development of the pure tin whisker formation.

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Palade, Catalin, Ionel Stavarache, Toma Stoica, and Magdalena Lidia Ciurea. "GeSi Nanocrystals Photo-Sensors for Optical Detection of Slippery Road Conditions Combining Two Classification Algorithms." Sensors 20, no. 21 (November 9, 2020): 6395. http://dx.doi.org/10.3390/s20216395.

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One of the key elements in assessing traffic safety on the roads is the detection of asphalt conditions. In this paper, we propose an optical sensor based on GeSi nanocrystals embedded in SiO2 matrix that discriminates between different slippery road conditions (wet and icy asphalt and asphalt covered with dirty ice) in respect to dry asphalt. The sensor is fabricated by magnetron sputtering deposition followed by rapid thermal annealing. The photodetector has spectral sensitivity in the 360–1350 nm range and the signal-noise ratio is 102–103. The working principle of sensor setup for detection of road conditions is based on the photoresponse (photocurrent) of the sensor under illumination with the light reflected from the asphalt having different reflection coefficients for dry, wet, icy and dirty ice coatings. For this, the asphalt is illuminated sequentially with 980 and 1064 nm laser diodes. A database of these photocurrents is obtained for the different road conditions. We show that the use of both k-nearest neighbor and artificial neural networks classification algorithms enables a more accurate recognition of the class corresponding to a specific road state than in the case of using only one algorithm. This is achieved by comparing the new output sensor data with previously classified data for each algorithm and then by performing an intersection of the algorithms’ results.

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Joseph, Shereena, Saurabh Pandey, Swagato Sarkar, and Joby Joseph. "Bound states in the continuum in resonant nanostructures: an overview of engineered materials for tailored applications." Nanophotonics 10, no. 17 (November 9, 2021): 4175–207. http://dx.doi.org/10.1515/nanoph-2021-0387.

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Abstract From theoretical model to experimental realization, the bound state in the continuum (BIC) is an emerging area of research interest in the last decade. In the initial years, well-established theoretical frameworks explained the underlying physics for optical BIC modes excited in various symmetrical configurations. Eventually, in the last couple of years, optical-BICs were exploited as a promising tool for experimental realization with advanced nanofabrication techniques for numerous breakthrough applications. Here, we present a review of the evolution of BIC modes in various symmetry and functioning mediums along with their application. More specifically, depending upon the nature of the interacting medium, the excitations of BIC modes are classified into the pure dielectric and lossy plasmonic BICs. The dielectric constituents are again classified as photonic crystal functioning in the subwavelength regime, influenced by the diffraction modes and metasurfaces for interactions far from the diffraction regime. More importantly, engineered functional materials evolved with the pure dielectric medium are explored for hybrid-quasi-BIC modes with huge-quality factors, exhibiting a promising approach to trigger the nanoscale phenomena more efficiently. Similarly, hybrid modes instigated by the photonic and plasmonic constituents can replace the high dissipative losses of metallic components, sustaining the high localization of field and high figure of merit. Further, the discussions are based on the applications of the localized BIC modes and high-quality quasi-BIC resonance traits in the nonlinear harmonic generation, refractometric sensing, imaging, lasing, nanocavities, low loss on-chip communication, and as a photodetector. The topology-controlled beam steering and, chiral sensing has also been briefly discussed.

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Sun, Yingwei, Jiancheng Luo, Tianjun Wu, Ya’nan Zhou, Hao Liu, Lijing Gao, Wen Dong, et al. "Synchronous Response Analysis of Features for Remote Sensing Crop Classification Based on Optical and SAR Time-Series Data." Sensors 19, no. 19 (September 28, 2019): 4227. http://dx.doi.org/10.3390/s19194227.

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Accurate crop classification is the basis of agricultural research, and remote sensing is the only effective measuring technique to classify crops over large areas. Optical remote sensing is effective in regions with good illumination; however, it usually fails to meet requirements for highly accurate crop classification in cloud-covered areas and rainy regions. Synthetic aperture radar (SAR) can achieve active data acquisition by transmitting signals; thus, it has strong resistance to cloud and rain interference. In this study, we designed an improved crop planting structure mapping framework for cloudy and rainy regions by combining optical data and SAR data, and we revealed the synchronous-response relationship of these two data types. First, we extracted geo-parcels from optical images with high spatial resolution. Second, we built a recurrent neural network (RNN)-based classifier suitable for remote sensing images on the geo-parcel scale. Third, we classified crops based on the two datasets and established the network. Fourth, we analyzed the synchronous response relationships of crops based on the results of the two classification schemes. This work is the basis for the application of remote sensing data for the fine mapping and growth monitoring of crop planting structures in cloudy and rainy areas in the future.

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Bogdanov, Nikita E., Valentina Milašinović, Boris A. Zakharov, Elena V. Boldyreva, and Krešimir Molčanov. "Pancake-bonding of semiquinone radicals under variable temperature and pressure conditions." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 76, no. 2 (March 24, 2020): 285–91. http://dx.doi.org/10.1107/s2052520620002772.

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The effects of temperature (100–370 K) and pressure (0–6 GPa) on the non-localized two-electron multicentric covalent bonds (`pancake bonding') in closely bound radical dimers were studied using single-crystal X-ray diffraction on a 4-cyano-N-methylpyridinium salt of 5,6-dichloro-2,3-dicyanosemiquinone radical anion (DDQ) as the sample compound. On cooling, the anisotropic structural compression was accompanied by continuous changes in molecular stacking; the discontinuities in the changes in volume and b and c cell parameters suggest that a phase transition occurs between 210 and 240 K. At a pressure of 2.55 GPa, distances between radical dimers shortened to 2.9 Å, which corresponds to distances observed in extended π-bonded polymers. Increasing pressure further to 6 GPa reduced the interplanar separation of the radicals to 2.75 Å. This may indicate that the covalent component of the interaction significantly increased, in accordance with the results of DFT calculations reported elsewhere [Molčanov et al. (2019), Cryst. Growth Des. 19, 391–402].

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王柯俨, 王柯俨, 李云松李云松, 孔繁锵孔繁锵, 吴成柯吴成柯, Keyan Wang Keyan Wang, Chengke Wu Chengke Wu, Fanqiang Kong Fanqiang Kong, and Lei Zhang Lei Zhang. "An improved partial SPIHT with classified weighted rate-distortion optimization for interferential multispectral image compression." Chinese Optics Letters 6, no. 5 (2008): 331–33. http://dx.doi.org/10.3788/col20080605.0331.

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Lausch, Dominik, Ronny Bakowskie, Michael Lorenz, S. Schweizer, Kai Petter, and Christian Hagendorf. "Classification of Recombination-Active Defects in Multicrystalline Solar Cells Made from Upgraded Metallurgical Grade (UMG) Silicon." Solid State Phenomena 178-179 (August 2011): 88–93. http://dx.doi.org/10.4028/www.scientific.net/ssp.178-179.88.

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In this contribution a classification of recombination active defects in multicrystalline silicon solar cells made from electronic grade (eg) and upgraded metallurgical grade (umg) silicon feedstock is introduced. On a macroscopic scale the classification is performed by using forward and reversed biased electroluminescence imaging (EL / ReBEL) and imaging of sub-band defect luminescence (ELsub). The luminescence behavior due to structural defects already present in the wafer can be divided into two groups based on their recombination and prebreakdown behavior. As a first step towards a more detailed analysis of the cause for these differences, the classification was also performed on microscopic scale. For this ReBEL and ELsub was performed under an optical microscope (µReBEL/µELsub) and EL was replaced by Electron Beam Induced Current (EBIC). The defect types observed on a macroscopic scale could also be observed on a microscopic scale; however, a third defect type had to be introduced. Finally we propose a qualitative model for the different classified types of recombination active defect structures that can explain the observed recombination and prebreakdown behavior.

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Huang, Shuan-Yu, Arvind Mukundan, Yu-Ming Tsao, Youngjo Kim, Fen-Chi Lin, and Hsiang-Chen Wang. "Recent Advances in Counterfeit Art, Document, Photo, Hologram, and Currency Detection Using Hyperspectral Imaging." Sensors 22, no. 19 (September 26, 2022): 7308. http://dx.doi.org/10.3390/s22197308.

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Forgery and tampering continue to provide unnecessary economic burdens. Although new anti-forgery and counterfeiting technologies arise, they inadvertently lead to the sophistication of forgery techniques over time, to a point where detection is no longer viable without technological aid. Among the various optical techniques, one of the recently used techniques to detect counterfeit products is HSI, which captures a range of electromagnetic data. To aid in the further exploration and eventual application of the technique, this study categorizes and summarizes existing related studies on hyperspectral imaging and creates a mini meta-analysis of this stream of literature. The literature review has been classified based on the product HSI has used in counterfeit documents, photos, holograms, artwork, and currency detection.

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Annamdas, Venu, and Chee Soh. "A Perspective of Non-Fiber-Optical Metamaterial and Piezoelectric Material Sensing in Automated Structural Health Monitoring." Sensors 19, no. 7 (March 27, 2019): 1490. http://dx.doi.org/10.3390/s19071490.

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Metamaterials are familiar in life sciences, but are only recently adopted in structural health monitoring (SHM). Even though they have existed for some time, they are only recently classified as smart materials suitable for civil, mechanical, and aerospace (CMA) engineering. There are still not many commercialized metamaterial designs suitable for CMA sensing applications. On the other hand, piezoelectric materials are one of the popular smart materials in use for about 25 years. Both these materials are non-fiber-optical in nature and are robust to withstand the rugged CMA engineering environment, if proper designs are adopted. However, no single smart material or SHM technique can ever address the complexities of CMA structures and a combination of such sensors along with popular fiber optical sensors should be encouraged. Furthermore, the global demand for miniaturization of SHM equipment, automation and portability is also on the rise as indicated by several global marketing strategists. Recently, Technavio analysts, a well-known market research company estimated the global SHM market to grow from the current US $ 1.48 billion to US $ 3.38 billion by 2023, at a compound annual growth rate (CAGR) of 17.93%. The market for metamaterial is expected to grow rapidly at a CAGR of more than 22% and the market for piezoelectric materials is expected to accelerate at a CAGR of over 13%. At the same time, the global automation and robotics market in the automotive industry is expected to post a CAGR of close to 8%. The fusion of such smart materials along with automation can increase the overall market enormously. Thus, this invited review paper presents a positive perspective of these non-fiber-optic sensors, especially those made of metamaterial designs. Additionally, our recent work related to near field setup, a portable meta setup, and their functionalities along with a novel piezoelectric catchment sensor are discussed.

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Ruzicka, Michal, Lukas Jabloncik, Petr Dejdar, Adrian Tomasov, Vladimir Spurny, and Petr Munster. "Classification of Events Violating the Safety of Physical Layers in Fiber-Optic Network Infrastructures." Sensors 22, no. 23 (December 6, 2022): 9515. http://dx.doi.org/10.3390/s22239515.

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Fiber-optic network infrastructures are crucial for the transmission of data over long and short distances. Fiber optics are also preferred for the infrastructure of in-building data communications. In this study, we use polarization analysis to ensure the security of the optical fiber/cables of the physical layer. This method exploits the changes induced by mechanical vibrations to polarization states, which can be easily detected using a polarization beam splitter and a balancing photodetector. We use machine learning to classify selected events that violate the safety of the physical layer, such as manipulation or temporary disconnection of connectors. The results show the resting state can be accurately distinguished from selected security breaches for a fiber route subjected to environmental disturbances, where individual events can be classified with nearly 99% accuracy.

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Shimonomura, Kazuhiro. "Tactile Image Sensors Employing Camera: A Review." Sensors 19, no. 18 (September 12, 2019): 3933. http://dx.doi.org/10.3390/s19183933.

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A tactile image sensor employing a camera is capable of obtaining rich tactile information through image sequences with high spatial resolution. There have been many studies on the tactile image sensors from more than 30 years ago, and, recently, they have been applied in the field of robotics. Tactile image sensors can be classified into three typical categories according to the method of conversion from physical contact to light signals: Light conductive plate-based, marker displacement- based, and reflective membrane-based sensors. Other important elements of the sensor, such as the optical system, image sensor, and post-image analysis algorithm, have been developed. In this work, the literature is surveyed, and an overview of tactile image sensors employing a camera is provided with a focus on the sensing principle, typical design, and variation in the sensor configuration.

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Xie, Zhang, He, You, Fan, Yu, and Li. "Automatic and Fast Recognition of On-Road High-Emitting Vehicles Using an Optical Remote Sensing System." Sensors 19, no. 16 (August 13, 2019): 3540. http://dx.doi.org/10.3390/s19163540.

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Optical remote sensing systems (RSSs) for monitoring vehicle emissions can be installed on any road and provide non-contact on-road measurements, that allow law enforcement departments to monitor emissions of a large number of on-road vehicles. Although many studies in different research fields have been performed using RSSs, there has been little research on the automatic recognition of on-road high-emitting vehicles. In general, high-emitting vehicles and low-emitting vehicles are classified by fixed emission concentration cut-points, that lack a strict scientific basis, and the actual cut-points are sensitive to environmental factors, such as wind speed and direction, outdoor temperature, relative humidity, atmospheric pressure, and so on. Besides this issue, single instantaneous monitoring results from RSSs are easily affected by systematic and random errors, leading to unreliable results. This paper proposes a method to solve the above problems. The automatic and fast-recognition method for on-road high-emitting vehicles (AFR-OHV) is the first application of machine learning, combined with big data analysis for remote sensing monitoring of on-road high-emitting vehicles. The method constructs adaptively updates a clustering database using real-time collections of emission datasets from an RSS. Then, new vehicles, that pass through the RSS, are recognized rapidly by the nearest neighbor classifier, which is guided by a real-time updated clustering database. Experimental results, based on real data, including the Davies-Bouldin Index (DBI) and Dunn Validity Index (DVI), show that AFR-OHV provides faster convergence speed and better performance. Furthermore, it is not easily disturbed by outliers. Our classifier obtains high scores for Precision (PRE), Recall (REC), the Receiver Operator Characteristic (ROC), and the Area Under the Curve (AUC). The rates of different classifications of excessive emissions and self-adaptive cut-points are calculated automatically in order to provide references for law enforcement departments to establish evaluation criterion for on-road high-emitting vehicles, detected by the RSS.

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Kuo, Chung-Feng Jeffrey, Wei-Ren Wang, and Jagadish Barman. "Automated Optical Inspection for Defect Identification and Classification in Actual Woven Fabric Production Lines." Sensors 22, no. 19 (September 24, 2022): 7246. http://dx.doi.org/10.3390/s22197246.

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This paper presents a turnkey integrated system that can be operated in real time for real textile manufacturers. Eight types of defects in woven fabric, including stain, broken end, broken weft, hole, nep, double pick, kinky weft and float can be recognized and classified. First, an image is captured by a CMOS industrial camera with a pixel size of 4600 × 600 above the batcher at 20 m/min. After that, the four-stage image processing procedure is applied to detect defects and for classification. Stage 1 is image pre-processing; the filtration of the image noise is carried out by a Gaussian filter. The light source is corrected to reduce the uneven brightness resulting from halo formation. The improved mask dodging algorithm is used to reduce the standard deviation of the corrected original image. Afterwards, the background texture is filtered by an averaging filter, and the mean value is corrected for histogram shifting, so that this system is robust to the texture and color changes of woven fabric. The binary segmentation threshold is determined using the mean value and standard deviation of an image with a normal sample. Stage 2 uses adaptive binarization for separation of the background and defects and to filter the noise. In Stage 3, the morphological processing is used before the defect contour is circled, i.e., four features of each block, including the defect area, the aspect ratio of the defect, the average gray level of the defect and the defect orientation, which are calculated according to the range of contour. The image defect recognition dataset consists of 2246 images. The results show that the detection success rate is 96.44%, and the false alarm rate is 3.21%. In Stage 4, the defect classification is implemented. The support vector machine (SVM) is used for classification, 230 defect images are used as training samples, and 206 are used as test samples. The experimental results show that the overall defect recognition rate is 96.60%, providing that the software and hardware equipment designed in this study can implement defect detection and classification for woven fabric effectively.

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Sun, Xiaoyong, Shaojing Su, Zhen Zuo, Xiaojun Guo, and Xiaopeng Tan. "Modulation Classification Using Compressed Sensing and Decision Tree–Support Vector Machine in Cognitive Radio System." Sensors 20, no. 5 (March 6, 2020): 1438. http://dx.doi.org/10.3390/s20051438.

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In this paper, a blind modulation classification method based on compressed sensing using a high-order cumulant and cyclic spectrum combined with the decision tree–support vector machine classifier is proposed to solve the problem of low identification accuracy under single-feature parameters and reduce the performance requirements of the sampling system. Through calculating the fourth-order, eighth-order cumulant and cyclic spectrum feature parameters by breaking through the traditional Nyquist sampling law in the compressed sensing framework, six different cognitive radio signals are effectively classified. Moreover, the influences of symbol length and compression ratio on the classification accuracy are simulated and the classification performance is improved, which achieves the purpose of identifying more signals when fewer feature parameters are used. The results indicate that accurate and effective modulation classification can be achieved, which provides the theoretical basis and technical accumulation for the field of optical-fiber signal detection.

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Mohamad Amin, Younessi Heravi, Golmakani Ebrahim, and Joharinia Sima. "A new approach for detecting sudden hypotension in hemodialysis by using dual-channel optical system." Journal of Innovative Optical Health Sciences 10, no. 01 (January 2017): 1650033. http://dx.doi.org/10.1142/s1793545816500334.

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Dialysis hypotension is one of the most prevalence symptoms of dialysis and occurs in 40% of treatment sessions. Detection and prediction of hypotension is important for the well-being of the patient and for optimizing treatment. The aim of this study was to construct optical system to monitor blood pressure (BP) continuously and without cuff in hemodialysis based on pulse transit time (PTT) method. To measure the BP changes, dual-channel optical system were developed. In this study, individuals were classified into two groups of normal and hemodialysis. In both groups, BP and consequently PTT were earned three times in different positions. After the initial calibration, the regression equation was drawn for each subject. In normal group, each subject was placed in the supine position and BP was measured both by designed system and sphygmomanometer cuff. During BP measurements, in addition to BP, blood pressure decline was also monitored by optical system. For hemodialysis group, the same measurement setup was adopted. In both groups, the error between cuff method and PTT was calculated. Correlation coefficients for BPcuff vs BPPTT were calculated and Bland–Altman plot was performed for the normal and hemodialysis groups. In this study 16 subjects participated. The results for normal group showed that maximum difference between cuff method and the present method was 14[Formula: see text]mmHg and for dialysis group was 16[Formula: see text]mmHg. Bland–Altman plot in normal group revealed limits of agreement from [Formula: see text]13.98 to 13.18[Formula: see text]mmHg. Considering hemodialysis group, limits of agreement were from [Formula: see text]15.94 to 13.88[Formula: see text]mmHg. The correlation coefficient was 0.74 for normal group and was 0.72 for hemodialysis group. The proposed system can monitor BP continuously and diagnose sudden hypotension. So it can be recommended as a useful method to indicate hypotension and can be used for dialysis unit.

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Mukundan, Arvind, Chia-Cheng Huang, Ting-Chun Men, Fen-Chi Lin, and Hsiang-Chen Wang. "Air Pollution Detection Using a Novel Snap-Shot Hyperspectral Imaging Technique." Sensors 22, no. 16 (August 19, 2022): 6231. http://dx.doi.org/10.3390/s22166231.

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Air pollution has emerged as a global problem in recent years. Particularly, particulate matter (PM2.5) with a diameter of less than 2.5 μm can move through the air and transfer dangerous compounds to the lungs through human breathing, thereby creating major health issues. This research proposes a large-scale, low-cost solution for detecting air pollution by combining hyperspectral imaging (HSI) technology and deep learning techniques. By modeling the visible-light HSI technology of the aerial camera, the image acquired by the drone camera is endowed with hyperspectral information. Two methods are used for the classification of the images. That is, 3D Convolutional Neural Network Auto Encoder and principal components analysis (PCA) are paired with VGG-16 (Visual Geometry Group) to find the optical properties of air pollution. The images are classified into good, moderate, and severe based on the concentration of PM2.5 particles in the images. The results suggest that the PCA + VGG-16 has the highest average classification accuracy of 85.93%.

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Huskić, Igor, and Tomislav Friščić. "Understanding geology through crystal engineering: coordination complexes, coordination polymers and metal–organic frameworks as minerals." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 74, no. 6 (December 1, 2018): 539–59. http://dx.doi.org/10.1107/s2052520618014762.

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Recent structural studies of organic minerals, coupled with the intense search for new carbon-containing mineral species, have revealed naturally occurring structures analogous to those of advanced materials, such as coordination polymers and even open metal–organic frameworks exhibiting nanometre-sized channels. While classifying such `non-conventional' minerals represents a challenge to usual mineral definitions, which focus largely on inorganic structures, this overview highlights the striking similarity of organic minerals to artificial organic and metal–organic materials, and shows how they can be classified using the principles of coordination chemistry and crystal engineering.

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Kumar, Harsh, Kamil Kuča, Shashi Kant Bhatia, Kritika Saini, Ankur Kaushal, Rachna Verma, Tek Chand Bhalla, and Dinesh Kumar. "Applications of Nanotechnology in Sensor-Based Detection of Foodborne Pathogens." Sensors 20, no. 7 (April 1, 2020): 1966. http://dx.doi.org/10.3390/s20071966.

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The intake of microbial-contaminated food poses severe health issues due to the outbreaks of stern food-borne diseases. Therefore, there is a need for precise detection and identification of pathogenic microbes and toxins in food to prevent these concerns. Thus, understanding the concept of biosensing has enabled researchers to develop nanobiosensors with different nanomaterials and composites to improve the sensitivity as well as the specificity of pathogen detection. The application of nanomaterials has enabled researchers to use advanced technologies in biosensors for the transfer of signals to enhance their efficiency and sensitivity. Nanomaterials like carbon nanotubes, magnetic and gold, dendrimers, graphene nanomaterials and quantum dots are predominantly used for developing biosensors with improved specificity and sensitivity of detection due to their exclusive chemical, magnetic, mechanical, optical and physical properties. All nanoparticles and new composites used in biosensors need to be classified and categorized for their enhanced performance, quick detection, and unobtrusive and effective use in foodborne analysis. Hence, this review intends to summarize the different sensing methods used in foodborne pathogen detection, their design, working principle and advances in sensing systems.

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De La Cruz Cortes, Victor, Kristian Segura Félix, Francisco Gerardo Flores García, and Mario Francisco Jesús Cepeda Rubio. "Comparison of Performance of Photodiodes with Different Active Areas Using Acrylic and Quartz Cuvettes for Spectrophotometry in Direct Measurements of Glucose in Water and Human Blood Plasma by Optical Means Using Near-Infrared." Journal of Spectroscopy 2022 (February 4, 2022): 1–8. http://dx.doi.org/10.1155/2022/5071553.

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Diabetes mellitus is one of the most relevant noncommunicable diseases; the WHO figures in its latest update that 422 million people suffer from it; additionally, it has remained for more than 20 years within the 10 main causes of death worldwide; this disease affects the population at any age; glucose measurement is used to assist the treatment of this disease by different methods that are classified as invasive, minimally invasive, and noninvasive, the latter being an area of recent development due that it is not traumatic for patients. This work consists of the experimental characterization of an optical system for plasma glucometry using near infrared by spectrophotometry. This glucometry system is based on the employ of an infrared LED with a wavelength of 1650 nm, a beam angle of 16°, and an output power of 1.6 mW that passes through the analyte (glucose in blood plasma) that is contained in cuvettes of different materials (acrylic and quartz) to subsequently affect a photodiode with different active areas ranging from 0.06 mm to 1.5 mm in order to evaluate the efficiency by comparing the sensitivity in the presence of glucose making additions ranging 100 mg/dl–1000 mg/dl within a dark chamber. The experiments showed that the use of photodiodes with a larger active area and the use of quartz cuvettes show a higher sensitivity compared to photodiodes with small active areas and the use of acrylic cuvettes. This configuration presented an R2 of 0.99 and a sensitivity of 0.225 mV/1 mg/dl of glucose; despite the fact that the initial voltage in each of the experimental repetitions varies, the downward voltage pattern is maintained; based on this, it is concluded that this method using this setup is feasible for plasma glucose measurement.

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Cifuentes, Renato, Dimitry Van der Zande, Christian Salas-Eljatib, Jamshid Farifteh, and Pol Coppin. "A Simulation Study Using Terrestrial LiDAR Point Cloud Data to Quantify Spectral Variability of a Broad-Leaved Forest Canopy." Sensors 18, no. 10 (October 8, 2018): 3357. http://dx.doi.org/10.3390/s18103357.

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In this analysis, a method for construction of forest canopy three-dimensional (3D) models from terrestrial LiDAR was used for assessing the influence of structural changes on reflectance for an even-aged forest in Belgium. The necessary data were extracted by the developed method, as well as it was registered the adjacent point-clouds, and the canopy elements were classified. Based on a voxelized approach, leaf area index (LAI) and the vertical distribution of leaf area density (LAD) of the forest canopy were derived. Canopy–radiation interactions were simulated in a ray tracing environment, giving suitable illumination properties and optical attributes of the different canopy elements. Canopy structure was modified in terms of LAI and LAD for hyperspectral measurements. It was found that the effect of a 10% increase in LAI on NIR reflectance can be equal to change caused by translating 50% of leaf area from top to lower layers. As presented, changes in structure did affect vegetation indices associated with LAI and chlorophyll content. Overall, the work demonstrated the ability of terrestrial LiDAR for detailed canopy assessments and revealed the high complexity of the relationship between vertical LAD and reflectance.

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ZHU, LING, TIMON CHENG-YI LIU, MIN WU, JIAN-QIN YUAN, and TONG-SHENG CHEN. "EXTRAOCULAR CELLULAR PHOTOTRANSDUCTION." Journal of Innovative Optical Health Sciences 02, no. 01 (January 2009): 93–100. http://dx.doi.org/10.1142/s1793545809000358.

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Photobiomodulation (PBM) is a modulation of monochromatic light or laser irradiation (LI) on biosystems. It is reviewed from the viewpoint of extraocular phototransduction in this paper. It was found that LI can induce extraocular phototransduction, and there may be an exact correspondence relationship of LI at different wavelengths and in different dose zones, and cellular signal transduction pathways. The signal transduction pathways can be classified into two types so that the Gs protein-mediated pathways belong to pathway 1, and the other pathways such as protein kinase Cs -mediated pathways and mitogen-activated protein kinase-mediated pathways belong to pathway 2. Almost all the present pathways found to mediate PBM belong to pathway 2, but there should be a pathway 1-mediated PBM. The previous studies were rather preliminary, and therefore further work should be done.

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Golovin, Igor S., Tatiana V. Ivleva, S. Jäger, P. Jencus, Hartmut Neuhäuser, S. A. T. Redfern, and C. Siemers. "Structure and Anelasticity of Fe-Ge Alloys." Solid State Phenomena 137 (March 2008): 59–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.137.59.

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Several ternary Fe – Ge - C alloys with Ge contents ranging between 3 and 27 at. % have been studied. The structure, anelastic, thermodynamic and kinetic phenomena in Fe - 3, - 12, - 19/21 and – 27 Ge have been examined by X-ray diffraction (XRD), heat flow (DSC), vibrating sample magnetometry (VSM), optical-light and scanning electron microscopy, and internal friction (IF) methods. The Fe - 3Ge and Fe - 12Ge alloys form b.c.c. solid solutions. A Snoek-type internal friction (P1) peak is recorded in the Fe - 3Ge alloy with parameters similar to those for α-Fe: Н = 0.86 eV, Δ = 0.015, β = 0.72 and τ0 = 2 × 10-15 s, showing that Ge atoms have little influence on the diffusivity of carbon in iron. The Fe - 12Ge alloy, with a Curie point around 1008 K, has several IF peaks: a broad Snoek-type (P1 and P2), the P3 peak caused by structural changes in as quenched specimens during annealing, and a P4 (Zener) peak at higher temperature (Tm ≈ 773 K at f = 2 Hz, β ≈ 0.7). The Fe - 21Ge alloy has bcc or bcc plus hexagonal structure depending on heat treatment. The structure of the Fe3Ge-type alloy (Fe - 27Ge) consists mainly of hexagonal phases, i.e. hexagonal ε (D019), β (B81), and cubic ε′ (L12), and exhibits corresponding magnetic ordering transitions below 873 K which are not well-reflected in the common Fe - Ge phase diagrams. In particular a high stability of the hexagonal ε phase at room temperature is noted. A broad internal friction relaxation peak with Δ = 0.0036, H ≈ 1.8 eV and τ 0 = 2 ⋅ 10-17 s is found in Fe – 27 Ge and is classified as a double Zener peak in the ε and β two-phase mixture.

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Ning, Mingqiang, Jinsong Tang, Heping Zhong, Haoran Wu, Peng Zhang, and Zhisheng Zhang. "Scale-Aware Network with Scale Equivariance." Photonics 9, no. 3 (February 28, 2022): 142. http://dx.doi.org/10.3390/photonics9030142.

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The convolutional neural network (CNN) has achieved good performance in object classification due to its inherent translation equivariance, but its scale equivariance is poor. A Scale-Aware Network (SA Net) with scale equivariance is proposed to estimate the scale during classification. The SA Net only learns samples of one scale in the training stage; in the testing stage, the unknown-scale testing samples are up-sampled and down-sampled, and a group of image copies with different scales are generated to form the image pyramid. The up-sampling adopts interpolation, and the down-sampling adopts interpolation combined with wavelet transform to avoid spectrum aliasing. The generated test samples with different scales are sent to the Siamese network with weight sharing for inferencing. According to the position of the maximum value of the classification-score matrix, the testing samples can be classified and the scale can be estimated simultaneously. The results on the MNIST and FMNIST datasets show that the SA Net has better performance than the existing methods. When the scale is larger than 4, the SA Net has higher classification accuracy than other methods. In the scale-estimation experiment, the SA Net can achieve low relative RMSE on any scale. The SA Net has potential for effective use in remote sensing, optical image recognition and medical diagnosis in cytohistology.

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Alathari, Mohammed Jawad Ahmed, Yousif Al Mashhadany, Mohd Hadri Hafiz Mokhtar, Norhafizah Burham, Mohd Saiful Dzulkefly Bin Zan, Ahmad Ashrif A Bakar, and Norhana Arsad. "Human Body Performance with COVID-19 Affectation According to Virus Specification Based on Biosensor Techniques." Sensors 21, no. 24 (December 15, 2021): 8362. http://dx.doi.org/10.3390/s21248362.

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Life was once normal before the first announcement of COVID-19’s first case in Wuhan, China, and what was slowly spreading became an overnight worldwide pandemic. Ever since the virus spread at the end of 2019, it has been morphing and rapidly adapting to human nature changes which cause difficult conundrums in the efforts of fighting it. Thus, researchers were steered to investigate the virus in order to contain the outbreak considering its novelty and there being no known cure. In contribution to that, this paper extensively reviewed, compared, and analyzed two main points; SARS-CoV-2 virus transmission in humans and detection methods of COVID-19 in the human body. SARS-CoV-2 human exchange transmission methods reviewed four modes of transmission which are Respiratory Transmission, Fecal–Oral Transmission, Ocular transmission, and Vertical Transmission. The latter point particularly sheds light on the latest discoveries and advancements in the aim of COVID-19 diagnosis and detection of SARS-CoV-2 virus associated with this disease in the human body. The methods in this review paper were classified into two categories which are RNA-based detection including RT-PCR, LAMP, CRISPR, and NGS and secondly, biosensors detection including, electrochemical biosensors, electronic biosensors, piezoelectric biosensors, and optical biosensors.

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Critchley-Marrows, Joshua J. R., Xiaofeng Wu, and Iver H. Cairns. "Treatment of Extended Kalman Filter Implementations for the Gyroless Star Tracker." Sensors 22, no. 22 (November 21, 2022): 9002. http://dx.doi.org/10.3390/s22229002.

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The literature since Apollo contains exhaustive material on attitude filtering, usually treating the problem of two sensors, a combination of state measuring and inertial devices. More recently, it has become popular for a sole attitude determination device to be considered. This is especially the case for a star tracker given its unbiased stellar measurement and recent improvements in optical sensor performance. The state device indirectly estimates the attitude rate using a known dynamic model. In estimation theory, two main attitude filtering approaches are classified, the additive and the multiplicative. Each refers to the nature of the quaternion update in the filter. In this article, these two techniques are implemented for the case of a sole star tracker, using simulated and real night sky image data. Both sets of results are presented and compared with each other, with a baseline established through a basic linear least square estimate. The state approach is more accurate and precise for measuring angular velocity than using the error-based filter. However, no discernible difference is observed between each technique for determining pointing. These results are important not only for sole device attitude determination systems, but also for space situational awareness object localisation, where attitude and rate estimate accuracy are highly important.

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Journal articles on the topic 'Molecular and optical physics not elsewhere classified'

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