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Controlled Assembly of Luminescent Lanthanide‑Organic Frameworks via Post‑Treatment of 3D‑Printed Objects 认领
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作者 Jiahui Huang Peiyi Wu 《纳微快报:英文版》 SCIE EI CAS 2021年第1期303-316,共14页
Complex multiscale assemblies of metal-organic frameworks are essential in the construction of largescale optical platforms but often restricted by their bulk nature and conventional techniques.The integration of nano... Complex multiscale assemblies of metal-organic frameworks are essential in the construction of largescale optical platforms but often restricted by their bulk nature and conventional techniques.The integration of nanomaterials and 3D printing technologies allows the fabrication of multiscale functional architectures.Our study reports a unique method of controlled 3D assembly purely relying on the post-printing treatment of printed constructs.By immersing a 3D-printed patterned construct consisting of organic ligand in a solution of lanthanide ions,in situ growth of lanthanide metal-organic frameworks(LnMOFs)can rapidly occur,resulting in macroscopic assemblies and tunable fluorescence properties.This phenomenon,caused by coordination and chelation of lanthanide ions,also renders a sub-millimeter resolution and high shape fidelity.As a proof of concept,a type of 3D assembled LnMOFsbased optical sensing platform has demonstrated the feasibility in response to small molecules such as acetone.It is anticipated that the facile printing and design approach developed in this work can be applied to fabricate bespoke multiscale architectures of functional materials with controlled assembly,bringing a realistic and economic prospect. 展开更多
关键词 3D printing Luminescent lanthanide-organic frameworks Macroscopic assembly In situ growth Optical sensing
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文章速递Using MAN and Coastal AERONET Measurements to Assess the Suitability of MODIS C6.1 Aerosol Optical Depth for Monitoring Changes from Increased Arctic Shipping 认领
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作者 Nicole Mölders Mariel Friberg 《大气污染开放期刊(英文)》 2020年第4期77-104,共28页
Collocated data of the moderate resolution imaging spectroradiometer (MO<span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">DIS) Collection 6.1 aerosol o... Collocated data of the moderate resolution imaging spectroradiometer (MO<span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">DIS) Collection 6.1 aerosol optical depths (AOD) at 3 km × 3 km north of 59.9</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">N over ocean were assessed at 550 nm by aerosol robotic network (AERONET) data from coastal sites and marine aerosol network (MAN) data from vessels during June to October 2006 to 2018. Typically, MODIS AOD w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> higher at low and lower at high values than the AERONET AOD. Discrepancies were largest for sites where the Earth’s surface around the site is very heterogeneous (Canadian Archipelago, coast of Greenland). Due to the higher likelihood for sea-ice, MAN and MODIS AOD differed stronger west of Greenland and over the Beaufort Sea than at location in the Greenland and Norwegian Seas and Atlantic. MODIS AOD well captured the inter-seasonal variability found in the AERONET AOD data (R = 0.933). At all sites, MO</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">DIS and AERONET AOD agreement improved as time progressed in the shipping season, hinting at errors in sea-ice vs. open water classification. Overall 75.3% of the MODIS AOD data fell within the limits of the error envelops of the AERONET/MAN AOD data with MAN ranging between 87.5% and 100%. Changes in both MODIS and AERONET mean AOD between two periods of same length (2006-2011, 2013-2018) were explainable by changes in emissions for all sites</span><span style="font-family:Verdana;">.</span> 展开更多
关键词 Aerosol Optical Depth over the Arctic Ocean MODIS Evaluation by AERONET and MAN Data Changes in Arctic Aerosol Optical Depth over the Ocean North of 59.9°N Arctic Shipping Season Aerosol Optical Depths
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Dielectric or plasmonic Mie object at air–liquid interface: The transferred and the traveling momenta of photon 认领
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作者 M R C Mahdy Hamim Mahmud Rivy +6 位作者 Ziaur Rahman Jony Nabila Binte Alam Nabila Masud Golam Dastegir Al Quaderi Ibraheem Muhammad Moosa Chowdhury Mofizur Rahman M Sohel Rahman 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第1期311-323,共13页
Considering the inhomogeneous or heterogeneous background, we have demonstrated that if the background and the half-immersed object are both non-absorbing, the transferred photon momentum to the pulled object can be c... Considering the inhomogeneous or heterogeneous background, we have demonstrated that if the background and the half-immersed object are both non-absorbing, the transferred photon momentum to the pulled object can be considered as the one of Minkowski exactly at the interface. In contrast, the presence of loss inside matter, either in the half-immersed object or in the background, causes optical pushing of the object. Our analysis suggests that for half-immersed plasmonic or lossy dielectric, the transferred momentum of photon can mathematically be modeled as the type of Minkowski and also of Abraham. However, according to a final critical analysis, the idea of Abraham momentum transfer has been rejected. Hence,an obvious question arises: whence the Abraham momentum? It is demonstrated that though the transferred momentum to a half-immersed Mie object(lossy or lossless) can better be considered as the Minkowski momentum, Lorentz force analysis suggests that the momentum of a photon traveling through the continuous background, however, can be modeled as the type of Abraham. Finally, as an interesting sidewalk, a machine learning based system has been developed to predict the time-averaged force within a very short time avoiding time-consuming full wave simulation. 展开更多
关键词 Abraham–Minkowski controversy DIELECTRIC interface machine learning OPTICAL FORCE laws OPTICAL PULLING FORCE OPTICAL tractor beams
Robust and high-speed rotation control in optical tweezers by using polarization synthesis based on heterodyne interference 认领
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作者 Wei Liu Dashan Dong +2 位作者 Hong Yang Qihuang Gong Kebin Shi 《光电进展(英文)》 2020年第8期23-29,共7页
The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual par... The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual particle.Here we report on a robust and high-speed rotation control in optical tweezers by using a novel linear polarization synthesis based on optical heterodyne interference between two circularly polarized lights with opposite handedness.The synthesized linear polarization can be rotated in a hopping-free scheme at arbitrary speed determined electronically by the heterodyne frequency between two laser fields.The experimental demonstration of a trapped vaterite particle in water shows that the precisely controlled rotation frequency of 300 Hz can be achieved.The proposed method will find promising applications in optically driven micro-gears,fluidic pumps and rotational micro-rheology. 展开更多
关键词 polarization modulation optical heterodyne optical tweezers optical rotation
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Silicon photonics for telecom and data‐com applications 认领
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作者 Kiyoshi Asakawa Yoshimasa Sugimoto Shigeru Nakamura 《光电进展(英文)》 2020年第10期31-56,共26页
In recent decades,silicon photonics has attracted much attention in telecom and data-com areas.Constituted of high refractive-index contrast waveguides on silicon-on-insulator(SOI),a variety of integrated photonic pas... In recent decades,silicon photonics has attracted much attention in telecom and data-com areas.Constituted of high refractive-index contrast waveguides on silicon-on-insulator(SOI),a variety of integrated photonic passive and active devices have been implemented supported by excellent optical properties of silicon in the mid-infrared spectrum.The main advantage of the silicon photonics is the ability to use complementary metal oxide semiconductor(CMOS)process-compatible fabrication technologies,resulting in high-volume production at low cost.On the other hand,explosively growing traffic in the telecom,data center and high-performance computer demands the data flow to have high speed,wide bandwidth,low cost,and high energy-efficiency,as well as the photonics and electronics to be integrated for ultra-fast data transfer in networks.In practical applications,silicon photonics started with optical interconnect transceivers in the data-com first,and has been now extended to innovative applications such as multi-port optical switches in the telecom network node and integrated optical phased arrays(OPAs)in light detection and ranging(LiDAR).This paper overviews the progresses of silicon photonics from four points reflecting the recent advances mentioned above.CMOS-based silicon photonic platform technologies,applications to optical transceiver in the data-com network,applications to multi-port optical switches in the telecom network and applications to OPA in LiDAR system. 展开更多
关键词 silicon photonics integration of photonics and electronics CMOS process-compatible fabrication optical interconnect transceiver optical multi-port switch optical phased array
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文章速递A Micro-Sized Light-Driven Pico-Second Oscillator 认领
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作者 Ali J. Sabbah R. Hamam 《应用数学与应用物理(英文)》 2020年第12期2793-2800,共8页
Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects... Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of Maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10<sup>-4</sup> N/m<sup>2</sup> and 0.1 ps period can be achieved. 展开更多
关键词 Radiation Force Optical Manipulation/Micromachines Instantaneous Electromagnetic Linear Momentum Density Linear Momentum Conservation Light Driven Oscillator
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文章速递Diurnal Variability of the Radiative Impact of Atmospheric Aerosols in Ouagadougou, Burkina Faso: A Seasonal Approach 认领
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作者 Bruno Korgo Bernard Zouma +5 位作者 Pétronille Kafando Nebon Bado Martial Zoungrana Issa Zerbo Jean-Claude Roger Joseph D. Bathiebo 《环境保护(英文)》 2020年第12期1089-1102,共14页
The objective of this work is to study the diurnal evolution of the radiative impact of atmospheric aerosols in an urban city located in the West African Sahel and the correlations with the main influencing factors of... The objective of this work is to study the diurnal evolution of the radiative impact of atmospheric aerosols in an urban city located in the West African Sahel and the correlations with the main influencing factors of local climate dynamics. The simulation was performed using a treatment chain including the GAME code. In the methodology, the atmosphere is modeled by 33 plane parallel layers and the effects of absorption, multiple scattering by particles and gas are taken account. An hour-by-hour calculation of radiative forcing at the top of the atmosphere, in the atmospheric layer and at the earth’s surface was performed. The data used as input are the monthly averages of optical properties, radiosonde measurements, daily synoptic measurements and surface albedo. The results show a parabolic diurnal course of a negative radiative impact at the top of the atmosphere with an extremum at 12 o'clock. Maximum cooling is observed shortly after sunrise and shortly after sunset. The largest annual deviations are noted between the months of March and December with respective maximum cooling values of -34 W/m<sup>2</sup> and -15.60 W/m<sup>2</sup>. On the earth’s surface, a cooling impact is observed with two diurnal peaks at sunrise and sunset, the greatest difference between the diurnal maximums is noted between March (-104.45 W/m<sup>2</sup>) and August (-54 W/m<sup>2</sup>). In the atmospheric layer, there is almost constant diurnal warming between 9 a.m. and 4 p.m. The maximum difference between the diurnal extremes is also noted between March (about 85 W/m<sup>2</sup>) and August (35 W/m<sup>2</sup>). Likewise, the study of the diurnal warming of the first atmospheric layer showed the extreme values in March (5.6&deg;C) and August (2.4&deg;C), these maximum values being always observed at around 12 o’clock. An analysis of similar works carried out in urban cities in various locations of the world has shown a relatively good accordance with the values obtained. This study highlights the radiative impact of Saharan desert dust, the effect of the local climate and the succession between dry season (November to May) and the rainy one (July to October), as well as the zenith solar angle and human activity. 展开更多
关键词 AERONET Optical Properties Radiative Forcing Harmattan Monsoon Sahara Desert
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Enhanced optical molasses cooling for Cs atoms with largely detuned cooling lasers 认领
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作者 张迪 李玉清 +7 位作者 王云飞 付永明 李鹏 刘文良 武寄洲 马杰 肖连团 贾锁堂 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第2期249-253,共5页
We report a detailed study of the enhanced optical molasses cooling of Cs atoms,whose large hyperfine structure allows to use the largely red-detuned cooling lasers.We find that the combination of a large frequency de... We report a detailed study of the enhanced optical molasses cooling of Cs atoms,whose large hyperfine structure allows to use the largely red-detuned cooling lasers.We find that the combination of a large frequency detuning of about-110 MHz for the cooling laser and a suitable control for the powers of the cooling and repumping lasers allows to reach a cold temperature of~5.5μK.We obtain 5.1×10^7 atoms with the number density around 1×10^12 cm^-3.Our result gains a lower temperature than that got in other experiments,in which the cold Cs atoms with the temperature of~10μK have been achieved by the optical molasses cooling. 展开更多
关键词 optical MOLASSES frequency DETUNING MAGNETO-OPTICAL TRAP laser COOLING
Synthesis, Growth and Characterization of an Organic Material: P-Chloroanilinium Ethanoate 认领
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作者 R. Sakunthaladevi L. Jothi 《矿物质和材料特性和工程(英文)》 2020年第3期133-148,共16页
Aromatic organic material of P-Chloroanilinium ethanoate (CAE) has been synthesized by condensation process using methanol as a solvent. The synthesized product is allowed to evaporate slowly at room temperature and c... Aromatic organic material of P-Chloroanilinium ethanoate (CAE) has been synthesized by condensation process using methanol as a solvent. The synthesized product is allowed to evaporate slowly at room temperature and crystals of cell dimension 25 × 29 × 10 mm3 were grown. The grown material was subjected to single crystal X-ray diffraction to obtain the cell parameters. The presence of functional groups in the grown material was confirmed by Fourier transform infrared and Fourier transform Raman spectral studies. The UV-VIS absorption spectrum reveals that the material has lower UV cut-off wavelength at 337 nm. Using the Kurtz Perry Powder method, the NLO activity was confirmed. Mechanical strength of the crystal was estimated by Vickers micro hardness test which shows that the material belongs to the soft category. The thermal behavior of the material was investigated by using thermo gravimetric and differential scanning calorimetric analyses. 展开更多
关键词 X-RAY DIFFRACTION LINEAR and NON-LINEAR OPTICAL Studies Mechanical PARAMETERS
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Gain-induced large optical torque in optical twist settings 认领
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作者 李艮艳 李肖 +1 位作者 张磊 陈君 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第8期264-269,共6页
Inducing a significant optical torque remains a challenging task,since the law of angular momentum conservation implies that one has to harvest a lot of light.Such a problem was partially resolved by using optical twi... Inducing a significant optical torque remains a challenging task,since the law of angular momentum conservation implies that one has to harvest a lot of light.Such a problem was partially resolved by using optical twist via strong internal multiple scattering to recycle the photons,and one can induce a large torque per unit of radiation cross section.By using the Maxwell stress tensor and the generalized Lorentz-Mie scattering theory for multi-spheres,we investigate the influence of gain materials in further amplifying optical torque in the optical twist settings.It is found that,when combined with a gain layer,the optical torque of lossy(both in PT-and non-PT-symmetric structures)or lossless(low dielectric materials)clusters at resonance could be one order of magnitude larger than those of a single layer and previous studied plasmonic double layer structures.Moreover,the gain-enhanced large opposite rotations(i.e.,optical twist)of the two layers arise at resonances in these structures.In contrast,in the gain-gain double-layer cluster,optical torques on both layers have no significant increase and the two layers rotate in the same direction at resonances.This work provides an elaborate investigation on the gain media-induced optical twist,which offers more choices for optical micromanipulation. 展开更多
关键词 optical torque optical twist gain medium double-layer clusters
High-power long-wave infrared laser based on polarization beam coupling technique 认领
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作者 Yingjie Shen Chuanpeng Qian +1 位作者 Xiaoming Duan Ruijun Lan 《高功率激光科学与工程:英文版》 SCIE CAS CSCD 2020年第2期19-23,共5页
We demonstrated a high-power long-wave infrared laser based on a polarization beam coupling technique.An average output power at 8.3µm of 7.0 W was achieved at a maximum available pump power of 107.6 W,correspond... We demonstrated a high-power long-wave infrared laser based on a polarization beam coupling technique.An average output power at 8.3µm of 7.0 W was achieved at a maximum available pump power of 107.6 W,corresponding to an optical-to-optical conversion of 6.5%.The coupling efficiency of the polarization coupling system was calculated to be approximately 97.2%.With idler single resonance operation,a good beam quality factor of~1.8 combined with an output wavelength of 8.3µm was obtained at the maximum output power. 展开更多
关键词 long-wave infrared laser optical parametric amplifier optical parametric oscillator polarization coupling
What the Photon Looks Like? 认领
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作者 Wei-Xing Xu 《光学与光子学期刊(英文)》 2020年第4期41-48,共8页
In this work, the spacetime distributions of the electric and magnetic fields of photon are revealed. It is first time found that the spacetime distributions of electric and magnetic fields of photon are source depend... In this work, the spacetime distributions of the electric and magnetic fields of photon are revealed. It is first time found that the spacetime distributions of electric and magnetic fields of photon are source dependent. Based on this discovery, some potential applications are discussed. 展开更多
关键词 PHOTON Electromagnetism RADIATION QUANTUM MECHANICS Optical Effect
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Correcting Wavefront Distortion of Dual-Wavelength Beams Due to Atmospheric Turbulence with a Correction Coefficient 认领
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作者 Xizheng Ke Xiaozhan Chen 《光学与光子学期刊(英文)》 2020年第4期64-77,共14页
In order to improve the correction effect of the adaptive optical system in coherent optical communication, we investigate the relative distortion between the wavefronts of different wavelengths of the beams transmitt... In order to improve the correction effect of the adaptive optical system in coherent optical communication, we investigate the relative distortion between the wavefronts of different wavelengths of the beams transmitted on the near-ground horizontal atmospheric turbulent links emitted by coherent optical communication system. And the situation is analyzed when the wavelength corresponding to the wavefront detected by the wavefront detector and the wavelength corrected by the deformed mirror are different, the influence of the wavelength factor on the adaptive optical system correction. We use a series of trigonometric functions and the Hankel transformation to derive the corrected residual variance and the Strehl ratio between the wavefront distortions of the wavelengths of the dual-wavelength combined beam in atmospheric turbulence. In relation to the parameters of the turbulent environment, the ensemble average of the wavefront difference corresponding to different wavelengths the derived is proposed as the coefficient to correct the dual-wavelength adaptive optical system. The results show that the statistic of the turbulence internal scale has a major influence on the difference between the wavefronts. By adding the correction coefficient, the signal light’s wavefront of the coherent optical communication system can be corrected more effectively by the dual-wavelength adaptive optical closure. 展开更多
关键词 COHERENT Optical Communication DUAL-WAVELENGTH WAVEFRONT Atmospheric TURBULENCE Adaptive Optics System WAVEFRONT Residual Variance
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Multi-Schlieren CT Measurements of Supersonic Microjets from Circular and Square Micro Nozzles 认领
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作者 Ahmad Zaid Nazari Yojiro Ishino +6 位作者 Yuta Ishiko Fumiya Ito Harumi Kondo Ryoya Yamada Takanori Motohiro Yoshiaki Miyazato Shinichiro Nakao 《流量控制、测量及可视化(英文)》 2020年第3期77-101,共25页
Instantaneous three-dimensional (3D) density distributions of a shock-cell structure of perfectly and imperfectly expanded supersonic microjets escaping into an ambient space are measured. For the 3D observation of su... Instantaneous three-dimensional (3D) density distributions of a shock-cell structure of perfectly and imperfectly expanded supersonic microjets escaping into an ambient space are measured. For the 3D observation of supersonic microjets, non-scanning 3D computerized tomography (CT) technique using a 20-directional quantitative schlieren optical system with flashlight source is employed for simultaneous schlieren photography. The 3D density distributions data of the microjets are obtained by 3D-CT reconstruction of the projection’s images using maximum likelihood-expectation maximization. Axisymmetric convergent-divergent (Laval) circular and square micro nozzles with operating nozzle pressure ratio 5.0, 4.5, 4.0, 3.67, and 3.5 have been studied. This study examines perfectly expanded, overexpanded, and underexpanded supersonic microjets issued from micro nozzles with fully expanded jet Mach numbers <em>M</em><em><sub>j</sub></em> ranging from 1.47 - 1.71, where the design Mach number is <em>M<sub>d</sub></em> = 1.5. A complex phenomenon for free square microjets called axis switching is clearly observed with two types “upright” and “diagonal” of “cross-shaped”. The initial axis-switching is 45<span style="white-space:nowrap;">°</span> within the first shock-cell range. In addition, from the symmetry and diagonal views of square microjets for the first shock-cells, two different patterns of shock waves are viewed. The shock-cell spacing and supersonic core length for all nozzle pressure ratios are investigated and reported. 展开更多
关键词 Supersonic Microjet Multi-Directional Quantitative Schlieren Optical System Three-Dimensional (3D) Measurement Computerized Tomography (CT) Circular and Square Micro Laval Nozzles
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Anatomical Study of MRI Optic Chiasm at the Bamako Anatomy Laboratory 认领
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作者 Babou Ba Siaka Diakité +5 位作者 Abdoulaye Kanté Tata Touré Moumouna Koné Nouhoum Ongo?ba Abdel Karim Koumaré Siaka Sidibé 《法医学与解剖学研究(英文)》 2020年第2期11-17,共7页
Roughly quadrangular, the chiasma presents many morphological variations. The optical chiasm, odd and symmetrical structure of the optical pathways, is a required passage of the axons of neurons for the visual pathway... Roughly quadrangular, the chiasma presents many morphological variations. The optical chiasm, odd and symmetrical structure of the optical pathways, is a required passage of the axons of neurons for the visual pathways. Any modification of its morphology evokes a pathological process, generally tumoral. The quality of MRI images rivals that of anatomical slices. So the MRI is essential for the study of the chiasma. The aim of this work was to study the morphometry of the optic chiasm in patients addressed for cerebral MRI to the imaging department of the university hospital of the POINT-G, during the period from July 29, to November 30, 2016. All patients who had a normal examination of the optic chiasma, numbering 15, were included in this study. In 86.66% of cases the chiasma had a quadrilateral form. Its average length was 8.73 mm and its average width was 13 mm. The average thickness was 4.13 mm. 展开更多
关键词 OPTICAL CHIASMA MRI LABORATORY ANATOMY
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Using the Optical Glauber Monte Carlo Model to Calculate R<sub><i>AA</i></sub>Related Results Produced by the ATLAS Collaboration 认领
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作者 Jingkai Wang Kevin Wang +1 位作者 Zhe Yang David Sun 《自然科学期刊(英文)》 2020年第3期65-73,共9页
The energy loss during jet quenching due to the existence of Quark Gluon Plasma (QGP) is calculated by Optical Glaube Monte Carlo model with data collected by ATLAS Collaboration using the LHC detector. An energy loss... The energy loss during jet quenching due to the existence of Quark Gluon Plasma (QGP) is calculated by Optical Glaube Monte Carlo model with data collected by ATLAS Collaboration using the LHC detector. An energy loss formula for this situation was modeled and took the form . The nuclear modification factor, RAA, for jets in a 208Pb + 208Pb nucleus collision with rapidity interval of ∣у∣=2.8 and the initial transverse momentum of 50 GeV ≤ pT ≤ 1000 GeV, are compared with various data plots produced by ATLAS Collaboration. RAA results are plotted in different centrality bins, which are defined by the distribution of number of participating nucleons Npart. The RAA value was found to slowly increase at lower transverse momenta and flatten out at higher transverse momenta. The model’s theoretical calculation results turned out to be similar to the plots produced by the ATLAS Collaboration using data from the LHC with small differences for higher systematic uncertainty events. 展开更多
关键词 RAA OPTICAL Monte Carlo Model QUARK-GLUON Plasma Jet Quenching Energy Loss
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Application of Reconstruction and Optimization Algorithms in Optical Tomography 认领
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作者 Umair Sajjad Hashmi Raheel Muzzammel +1 位作者 Rabia Arshad Saba Mehmood 《世界工程和技术(英文)》 2020年第2期188-203,共16页
Optical tomography is a non-invasive technique that uses visible or near infrared radiation to analyze biological tissues. Researchers take immense attention towards advancement in optical tomography because of its lo... Optical tomography is a non-invasive technique that uses visible or near infrared radiation to analyze biological tissues. Researchers take immense attention towards advancement in optical tomography because of its low cost and an advantage of providing anatomical information. Based on the information of optical characteristics, forward and inverse problem of tomography are solved. In this research, finite element method is employed for forward problem and gradient-based optimization algorithm is developed for inverse problem of optical tomography. It is found from simulations that information about imaging is processed more distinctly and in less computational time. Normal and abnormal conditions in imaging are readily distinguished.?Simulations are carried out in Matlab. Different scenarios are developed and are simulated to validate the performance of reconstruction and optimization algorithms in optical tomography. 展开更多
关键词 Optical TOMOGRAPHY Medical Imaging Image RECONSTRUCTION Optimization FORWARD PROBLEM INVERSE PROBLEM
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Application of Optical Flow Analysis to Shadowgraph Images of Impinging Jet 认领
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作者 Masato Hijikuro Masayuki Anyoji 《流量控制、测量及可视化(英文)》 2020年第4期173-187,共15页
In this study, we apply the optical flow method to the time-series shadowgraph images of impinging jets using a high-speed video camera with high spatial and temporal resolution. This image analysis provides quantitat... In this study, we apply the optical flow method to the time-series shadowgraph images of impinging jets using a high-speed video camera with high spatial and temporal resolution. This image analysis provides quantitative velocity vector fields in the object space without tracer particles. The analysis results clearly capture the details of the coherent vortex structure and its advection from the shear layer of the free jet. Although the results still leave challenges for the quantitative validation, the results show that this analysis method is effective for understanding the details of the physical phenomenon based on the quantitative values extracted from the shadowgraph images. 展开更多
关键词 Impinging Jet Optical Flow SHADOWGRAPH Image Analysis Velocity Vector
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Micro-scale Additive Manufacturing Using the Optical Potential Generated by a Bessel Beam 认领
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作者 Masaki Michihata Makoto Yokei +1 位作者 Shotaro Kadoya Satoru Takahashi 《纳米制造与计量(英文)》 2020年第4期292-298,共7页
In this study,we proposed a novel micro-scale additive manufacturing method based on the optical potential formed by a Bessel beam.The proposed technique is expected to show no deterioration in manufacturing resolutio... In this study,we proposed a novel micro-scale additive manufacturing method based on the optical potential formed by a Bessel beam.The proposed technique is expected to show no deterioration in manufacturing resolution due to heat genera-tion,to be applicable to various materials,and to be able to be performed in an air environment.The basic principle of the proposed method involves accumulating and stacking particles dispersed in air by using optical radiation pressure.In this paper,the trajectory of the accumulated particles was numerically estimated and experimentally observed.The numerical and experimental results agreed well;specfially,the back ground flow carried the particles to the optical axis of the Bessel beam,and then the particles were localized at the bottom of the optical potential valley on the substrate.Finally,a pillar structure was fabricated with polystyrene particles having a diameter of 1 um,which indicated that the proposed technique was promising for practical applications. 展开更多
关键词 Additive manufacturing Optical radiation pressure Optical trapping potential Bessel beam NANOPARTICLES
Comparative Analysis of the Characteristics of Polar and Non-Polar Spiral Polarization Rotators 认领
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作者 Andrey L. Sokolov 《光学与光子学期刊(英文)》 2020年第2期13-27,共15页
Spiral polarization rotators, rotating polarization ellipse axes clockwise or counterclockwise, depending on the azimuth angle in the transverse plane, are considered. It is shown that spiral polarization rotators lea... Spiral polarization rotators, rotating polarization ellipse axes clockwise or counterclockwise, depending on the azimuth angle in the transverse plane, are considered. It is shown that spiral polarization rotators lead to a change in the order of optical vortices with circular polarization. A comparative analysis of spiral rotators of two types (polar and non-polar) is carried out, using a mirror that allows light to pass in the opposite direction through the rotator. The effect of spiral rotators on optical vortices in a resonator is studied. It is shown that spiral rotators can preserve or accumulate changes of the vortex order during the passage of the beam in both directions. The properties of the spiral rotator and the cube-corner reflector with a special phase-correcting coating, as a diffractive polarization-optical element, are compared. 展开更多
关键词 Polarization-Symmetric Structures Optical Vortex Circular POLARIZATION SPIRAL POLARIZATION ROTATOR Cube-Corner REFLECTOR
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