2020
2020
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Record 85 of
Title:A novel photostable near-infrared-to-near-infrared fluorescent nanoparticle for in vivo imaging
Author(s):Fan, Qi(1,2); Cui, Xiaoxia(1,3); Wang, Quan(1); Gao, Peng(4); Shi, Shengjia(5); Wen, Weihua(6); Guo, Haitao(1,3); Xu, Yantao(1,3); Peng, Bo(1,3)Source: Journal of Biomedical Materials Research - Part B Applied Biomaterials Volume: 108 Issue: 7 DOI: 10.1002/jbm.b.34622 Published: October 1, 2020Abstract:Water-soluble K5HoLi2F10 (KHLF) nanoprobes with the excitation and emission both in the near-infrared (NIR) region were developed and first demonstrated for in vivo imaging of living mice. The PEG400 coating endows the nanoprobes with good water solubility and biocompatibility. Doping with Ho3+ ions is capable of emitting NIR fluorescence with two peaks centered, respectively, at 887 and 1,180 nm once excited by a 808 nm laser; meanwhile, it also possess good photothermal conversion performance. The KHLF matrix with specifically structure of large ion-distance and low photon energy imparts the nanoprobes low quenching effect and excellent photostability (fluorescence decrease 2). The nanoparticles (NPs) were tested for in vitro bioimaging with living mice. The results show the NPs have low biotoxicity, rapid metabolism, normal biodistribution, together with the photothermal imaging performance and a high-contrast fluorescence images (signal-to-background ratio of 14:1). The superior performances of these nanoprobes in vivo imaging of mice proclaim the great potential of this type of probe for high-contrast imaging and photothermal treatment in practical applications. ? 2020 Wiley Periodicals, Inc.Accession Number: 20202008646670 -
Record 86 of
Title:Effect of cation vacancies on the optical and dielectric properties of KSr2Nb5O15: A first-principles study
Author(s):Chen, Qian(1); Gao, Feng(1); Xu, Jie(1); Wu, Changying(2); Cao, Shuyao(1); Guo, Yiting(1); Pawlikowska, Emilia(3); Szafran, Mikolaj(3); Cheng, Guanghua(2,4)Source: Journal of the American Ceramic Society Volume: 103 Issue: 3 DOI: 10.1111/jace.16909 Published: March 1, 2020Abstract:Using first-principles calculations, the effect of cation vacancies on the electronic structures and optical characters of KSr2Nb5O15 (KSN) lead-free ferroelectrics are investigated. The calculated dielectric properties are demonstrated by the experimental results. The cation vacancies involve K+ vacancies (KSN-K), Sr2+ vacancies (KSN-Sr), and coexisting K+ and Sr2+ vacancies (KSN-K&Sr). When these cation vacancies exist in KSN, the unit cell volumes decrease, leading to phase transition from tetragonal to orthorhombic, and the cation vacancies show strong effects on the band gap of KSN, declining by 1.46%-9.46%. The optical properties including the static dielectric constants, refraction, and extinction coefficient of KSN-K, KSN-Sr, and KSN-K&Sr increase more than those of KSN without vacancies, but the reflectivity and loss function decrease. All structures with cation vacancies are mainly refractive in the 0-4?eV photon energy range and are reflective at 5-8?eV. The refractivity increases and reflectivity decreases after vacancies occur. KSN-Sr has the largest static dielectric constant while KSN-K&Sr has the smallest values. The dielectric constant can be adjusted in the range of 25% by controlling the cation vacancies. The calculated dielectric properties are in good agreement with the experimental results. The results pave the way to regulate the optical and dielectric properties of lead-free ferroelectrics by controlling different cation vacancies. ? 2019 The American Ceramic SocietyAccession Number: 20194907776347 -
Record 87 of
Title:Instrument design and forward modeling of near-space wind and temperature sensing interferometer
Author(s):He, Wei-Wei(1); Wu, Kui-Jun(2); Fu, Di(3); Wang, Hou-Mao(4); Li, Juan(3)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 28 Issue: 8 DOI: 10.3788/OPE.20202808.1678 Published: August 1, 2020Abstract:Wind and temperature measurements in near-space (20-100 km) play a prominent part in the development of atmospheric physics and space science, which are of considerable academic and application value. The atmospheric wind and temperature fields in the stratosphere, mesosphere, and lower thermosphere (40-80 km) can be simultaneously detected using the wide-angle Michelson interferometer with the radiation source observation of the limb-viewing O2(a1Δg) airglow near 1.27 μm. Hence, a near-space wind and temperature sensing interferometer was designed in this study, and its modeling and forward simulation were conducted. Based on the characteristics of the radiation spectrum and principle of spectral line selection, two sets of different intensity lines were employed for wind and temperature detection.The weak group was used for low altitude measurement to avoid the influence of self absorption on the measurement results; the strong line was used for high altitude detection to achieve high measurement accuracy. The forward model was composed of the system parameters of atmosphere radiation transmission module, Michelson interferometer module, filter module, optical system, sensor array, and infrared focal plane. Through forward modeling, the limb-viewing image was obtained, and the uncertainty of wind velocity and temperature measurement was analyzed. The numerical simulation results show that the wind measurement accuracy is 1-3 m/s and temperature measurement accuracy is 1-3 K in the height range of 40-80 km, which meet the requirements of wind temperature detection accuracy in adjacent space. ? 2020, Science Press. All right reserved.Accession Number: 20203509096421 -
Record 88 of
Title:Computational phase microscopy with modulated illumination
Author(s):Gao, Peng(1,2); Wen, Kai(1); Liu, Lixin(1); Zheng, Juanjuan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11438 Issue: DOI: 10.1117/12.2551362 Published: 2020Abstract:Conventional optical microscopy provides only intensity images, for which the contrast is induced by fluorescence or the absorption of the sample on the illumination light. Yet, the phase, polarization, and spectrum information of the sample is lost. Meanwhile, limited by design, conventional optical microscopy suffers from the conflict between spatial resolution and field of view (FOV). Modulated illuminations based computational microscopy (CM), which joints front-end optics and post-detection signal processing can, in general, extend the capability of conventional microscopy; for example, it allows the acquisition of the intensity, phase, polarization information, and enhance the spatial resolution within a large FOV. In this paper, modulated illumination based CM was exploited for implementation of phase imaging, resolution enhancement, dual-modality imaging. First, modulated illumination based CM provides quantitative amplitude and phase images, revealing the 3D shape and the inner structure of transparent or translucent samples in the absence of fluorescent labeling. Second, pupil-segmentation based CM measures the aberration of focus modulation microscopy (FMM). Hence, the resolution and SNR of FMM was enhanced after the aberration compensation. Third, phase and fluorescence dualmodality imaging was implemented in confocal laser scanning microscopy (CLSM) by extending the depth of field (DOF) of the CLSM system with a tunable acoustic gradient index of refraction (TAG) lens, providing complementary information (structural/functional) with pixel-to-pixel correspondence for the same sample. Furthermore, the combination of the two imaging modalities enables standalone determination of the refractive index of live cells. ? 2020 SPIE.Accession Number: 20201408379686 -
Record 89 of
Title:Space-based missile warning technology based on fine spectrum of potassium atoms in exhaust plumes
Author(s):Wang, Sufeng(1); Wu, Kuijun(2); Feng, Yutao(1); Chang, Chenguang(1); Dang, Jianan(1); Hu, Bingliang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11566 Issue: DOI: 10.1117/12.2574904 Published: 2020Abstract:The main propose of this paper is to discuss the possibility of a space-based early warning technology for missiles in boost phase based on the near-infrared fine spectrum of potassium atoms in the exhaust plume. Emission transfer link from the exhaust plume to the detector is established in combination with the observation model of satellite and target on the ground. Line-by-line integral method is used to calculate the characteristic spectrum of potassium atoms. The result shows the potassium line have high spectral emissivity and narrow bandwidth. The analyses on the atmospheric transmission and background radiation indicate that the atmospheric transmission of the 769.896 nm potassium line is higher than that of the 766.490 nm potassium line which lies on top of an O2line, and the irradiance of the 769.896 nm line is stronger than that of background and the 766.490 nm line. Considering atmospheric transmission and background radiation, it is suitable to choose the 769.896 nm line to detect the exhaust plume of the missile. According to the characteristic of potassium atoms emission line with narrow bandwidth, a 1.2 nm wide filter centered on 770nm is used to extract target signal. The maximum detection range and other indexes are evaluated. The simulation results show that ultra-narrow band filter can achieve a large degree of background suppression, and the system performance indexes meet the detection requirements. Therefore, it is feasible that missile detection can be realized by using near-infrared fine spectrum of potassium atoms. ? 2020 SPIE. All rights reserved.Accession Number: 20204909589273 -
Record 90 of
Title:Visible and Near Infrared Spectral Analysis of the Lubricating Oil Dynamic Viscosity Based on Quantum Genetic-Neural Network Algorithm
Author(s):Liu, Chen-Yang(1,2); Tang, Xing-Jia(3); Yu, Tao(3); Wang, Tai-Sheng(1); Lu, Zhen-Wu(1); Yu, Wei-Xing(3)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 40 Issue: 5 DOI: 10.3964/j.issn.1000-0593(2020)05-1634-06 Published: May 1, 2020Abstract:Dynamic viscosity is one of the most important quality factors of lubricating oil. For the safety of high-speed railway, it is necessary to develop a real-time, fast and non-destructive method to monitor the status of the gearbox. Here we propose a new method that utilizes the quantum genetic-neural network algorithm to quantitatively analyze the visible and near-infrared spectra of lubricant acquired by a micro-spectrometer module. The method not only realizes non-destructive rapid real-time detection of the dynamic viscosity of high-speed railway transmission lubricating oil, but also further improves the prediction accuracy of the lubricating oil dynamic viscosity. Thanks to its excellent performance and small size, the miniature spectrometer has been widely used as a portable and nondestructive device. Here, two kinds of micro-spectral modules with visible/short-wave-infrared and near-infrared waveguide gratings are coupled with optical fibers and obtain a wide spectral range from 330 to 1 700 nm. Here the integrated waveguide and propagating makes the spectrometer compact and small. In experiment, a total of 78 lubricant samples with 13 different viscosity lubricants were prepared for spectral measurement by the micro-spectrometer. The raw spectral data was pre-processed using the Savitzky-Golay convolution smoothing and the first-order differentiation to eliminate the baseline drift and background noise. Next, principal component analysis and Mahalanobis distance algorithm were used to identify the samples outside the concentration boundary, and three out-of-bound samples were excluded. Finally, the BP neural network and the quantum genetic neural network methods were employed for quantitative analyses and the results are compared, respectively. The quantum genetic algorithm is a probabilistic evolutionary algorithm that combines the advantages of quantum computing and genetic algorithm. It uses the form of quantum chromosomes and quantum logic gates for global searching. Therefore, the quantum genetic algorithm can be used to optimize the weight and the threshold of neural network, and the modeling efficiency and accuracy can be improved significantly. In this paper, BP neural network algorithm and quantum genetic neural network algorithm were modeled and simulated respectively. Ten samples were randomly selected from 75 samples as prediction sets, and the remaining 65 were as modeling sets. In the quantum genetic algorithm, the population number was set to 40 and the termination algebra was 200. The optimization results showed that the algorithm could obtain the optimal solution quickly after training of only 81 generations. A comparison of the predicted results showed that the quantum genetic algorithm was much better than the BP neural network, the root mean square error of the prediction was significantly reduced from 0.345 5 to 0.029 4, and the coefficient of determination was increased from 0.850 4 to 0.979 9. This work has developed an effective method for compact, non-destructive, rapid and real-time detection of the dynamic viscosity of the lubricant and would find potential uses for the safety monitoring of high-speed trains. ? 2020, Peking University Press. All right reserved.Accession Number: 20202308784988 -
Record 91 of
Title:Structured active fiber fabrication and characterization of a chemically high-purified Dy3+-doped chalcogenide glass
Author(s):Xiao, Xusheng(1); Xu, Yantao(1,2); Cui, Jian(1,2); Liu, Xiaogang(1); Cui, Xiaoxia(1,2); Wang, Xunsi(3); Dai, Shixun(3); Guo, Haitao(1,2)Source: Journal of the American Ceramic Society Volume: 103 Issue: 4 DOI: 10.1111/jace.16921 Published: April 1, 2020Abstract:By conventional melt-quenching techniques, a series of Dy3+-doped (0.1 to 1.0?wt%) Ga5Ge20Sb15S60 bulk glasses were fabricated and their potential for developing mid-infrared fiber laser beyond 4?μm were evaluated, in which the optimal Dy3+ doping concentration was found to be 0.3?wt% and the largest laser quality factor value (σe?×?τmea?=?2.62?×?10?23?cm2?s) among all of the Dy3+-doped chalcogenide glass was obtained. On this basis, through using the chemical purification methods with chlorine gas combined with the dynamic distillation process, the high-purity GGSS glasses with low O–H and S–H absorptions were successfully fabricated, which was confirmed by the optimized mid-infrared linear transmittance and improved fluorescent lifetimes of Dy3+: 6H13/2, 6H11/2 levels. Furthermore, for the first time to the best of our knowledge, the Dy3+-doped, single-mode, and double-cladding chalcogenide fibers with the core/cladding ratios of 125:60:11 and 125:66:11.5 were achieved by a multistage rod-in-tube fiber drawing process and extrusion methods, respectively. The GeS2-based fiber exhibits excellent transmission performance at 1.0-5.0?μm: 3.0?dB/m at 2.9?μm (O–H), 2.4?dB/m at 4.1?μm (S–H). Combining the advantages of high-purity, high doping concentration and single-mode double-cladding structure, the optimized active fiber should be an ideal efficient and low-threshold medium toward mid-infrared fiber laser beyond 4?μm. ? 2019 The American Ceramic SocietyAccession Number: 20195007823189 -
Record 92 of
Title:A pedestrian extraction algorithm based on single infrared image
Author(s):Zhou, Dongmei(1); Qiu, Shi(2); Song, Yang(3); Xia, Kaijian(4)Source: Infrared Physics and Technology Volume: 105 Issue: DOI: 10.1016/j.infrared.2020.103236 Published: March 2020Abstract:Infrared image can show the state of objects at night, which is an important way to obtain the information of objects at night. To solve the extraction of pedestrians completely from single infrared image, we analyze the features of infrared image and propose a pedestrian extraction algorithm based on single infrared image. Firstly, neighborhood and multi-projection models are constructed to locate suspected pedestrian areas. Then, the head in the infrared imaging centripetally is used to build the template. Finally, the weighted fusion of global template and head template is used to extract pedestrians. Experiments show that the algorithm proposed in this paper can extract pedestrians in various motion modes under complex conditions, and has strong robustness. ? 2020 Elsevier B.V.Accession Number: 20200908240268 -
Record 93 of
Title:Manipulation of Airy Beams in Dynamic Parabolic Potentials
Author(s):Liu, Feng(1); Zhang, Jingwen(1); Zhong, Wei-Ping(2); Beli?, Milivoj R.(3); Zhang, Yu(4); Zhang, Yanpeng(1); Li, Fuli(5); Zhang, Yiqi(1)Source: Annalen der Physik Volume: 532 Issue: 4 DOI: 10.1002/andp.201900584 Published: April 1, 2020Abstract:The propagation of finite energy Airy beams in dynamic parabolic potentials, including uniformly moving, accelerating, and oscillating potentials, is investigated. The propagation trajectories of Airy beams are strongly affected by the dynamic potentials, but the periodic inversion of the beam remains invariant. The results may broaden the potential applications of Airy beams, and also enlighten ideas on Airy beam manipulation in nonlinear?regimes. ? 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimAccession Number: 20201208321446 -
Record 94 of
Title:Multi-directional reconstruction algorithm for panoramic camera
Author(s):Qiu, Shi(1); Li, Bin(2); Cheng, Keyang(3); Zhang, Xiao(2); Duan, Guifang(4); Li, Feng(5)Source: Computers, Materials and Continua Volume: 65 Issue: 1 DOI: 10.32604/cmc.2020.09708 Published: July 23, 2020Abstract:A panorama can reflect the surrounding scenery because it is an image with a wide angle of view. It can be applied in virtual reality, smart homes and other fields as well. A multi-directional reconstruction algorithm for panoramic camera is proposed in this paper according to the imaging principle of dome camera, as the distortion inevitably exists in the captured panorama. First, parameters of a panoramic image are calculated. Then, a weighting operator with location information is introduced to solve the problem of rough edges by taking full advantage of pixels. Six directions of the mapping model are built, which include up, down, left, right, front and back, according to the correspondence between cylinder and spherical coordinates. Finally, multi-directional image reconstruction can be realized. Various experiments are performed in panoramas (1024×1024) with 30 different shooting scenes. Results show that the azimuth image can be reconstructed quickly and accurately. The fuzzy edge can be alleviated effectively. The rate of pixel utilization can reach 84%, and it is 33% higher than the direct mapping algorithm. Large scale distortion is also further studied. ? 2020 Tech Science Press. All rights reserved.Accession Number: 20203809206020 -
Record 95 of
Title:Detection of Solitary Pulmonary Nodules Based on Brain-Computer Interface
Author(s):Qiu, Shi(1); Li, Junjun(2); Cong, Mengdi(3); Wu, Chun(4); Qin, Yan(4); Liang, Ting(2,5)Source: Computational and Mathematical Methods in Medicine Volume: 2020 Issue: DOI: 10.1155/2020/4930972 Published: 2020Abstract:Solitary pulmonary nodules are the main manifestation of pulmonary lesions. Doctors often make diagnosis by observing the lung CT images. In order to further study the brain response structure and construct a brain-computer interface, we propose an isolated pulmonary nodule detection model based on a brain-computer interface. First, a single channel time-frequency feature extraction model is constructed based on the analysis of EEG data. Second, a multilayer fusion model is proposed to establish the brain-computer interface by connecting the brain electrical signal with a computer. Finally, according to image presentation, a three-frame image presentation method with different window widths and window positions is proposed to effectively detect the solitary pulmonary nodules. ? 2020 Shi Qiu et al.Accession Number: 20214511122084 -
Record 96 of
Title:One-shot x-ray detection based on the instantaneous change in the refractive index of GaAs
Author(s):Gao, Guilong(1); He, Kai(1); Yi, Tao(2); Lv, Meng(3); Yuan, Yun(4); Yan, Xin(1); Yin, Fei(1); Li, Shaohui(1); Hu, Ronghao(3); Wang, Tao(1); Tian, Jinshou(1)Source: AIP Advances Volume: 10 Issue: 4 DOI: 10.1063/5.0005771 Published: April 1, 2020Abstract:An interferometric semiconductor x-ray detection system is proposed in this paper. The system is based on the RadOptic effect, and it utilizes Fabry-Perot interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor (GaAs). In this work, the intrinsic time resolution and the sensitivity of a Fabry-Perot interferometric sensor were systemically studied. Based on the transient free carrier absorption model, the prototype system was established to quantitatively measure the time-dependent x-ray flux with the deconvolution algorithm for the first time. The time resolution of the detection system was approximately 21 ps, and the output signal induced by an x-ray pulse showed a high signal-to-noise ratio and immunity to electromagnetic interference. This interferometer will enable x-ray bang-time and fusion burn-history measurements in inertial confinement fusion with higher time resolution. ? 2020 Author(s).Accession Number: 20201708532559