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Influence of K plus on the crystal structure, defect, and scintillation performances of LYSO:Ce crystals

JOURNAL OF ALLOYS AND COMPOUNDS 2024年 998卷

作者： Qiu, peng Xue, Zhongjun Li, Chengyi Zhang, Aochen Zhao, shuwen Zheng, Xiang Zhang, Zhe Ding, Dongzhou Chinese Acad Sci Shanghai Inst Ceram Shanghai 201899 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China

Lu 1.8 Y 0.2 SiO 5 :Ce (LYSO:Ce) crystals have become the material of choice for the current application of commercial TOF-PETs due to their high light output, short decay time, and fast rise time. In this study, a series of K + co-doped LYSO:Ce crystals were prepared by the mu-PD method, in which the K + concentrations were 0, 0.2 atom %, 0.6 atom %, and 1.0 atom %, respectively. It was found that the scintillation performances were simultaneously optimized when the K + concentration was 0.6 atom %. Compared to the sample of LYSO:Ce, LYSO:Ce, 0.6 atom % K showed an approximately 12.6 % increase in light yield, a shortening of the fastest scintillation decay time to 38.3 ns, and a 1.4-fold decrease in afterglow level. Moreover, the K + could replace the Lu 3 + site but could not cause the transition of Ce 3 + to Ce 4 + . Meanwhile, the connection between optical and luminescence performances and K + concentration was discussed. The luminescence contribution of Ce2 became stronger with the K + concentration increased. Furthermore, the research on K + co-doping of LYSO:Ce crystals could offer better knowledge and be informative for the selection of future co-dopants.

关键词： Optical materials Oxide materials Crystal growth Crystal structure Optical spectroscopy

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Systematic Comparison of Power Corridor Classification Methods from ALS Point Clouds

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REMOTE SENSING 2019年第17期11卷 1961-1961页

作者： peng, shuwen Xi, Xiaohuan Wang, Cheng Dong, Pinliang Wang, Pu Nie, Sheng Chinese Acad Sci Inst Remote Sensing & Digital Earth Key Lab Digital Earth Beijing 100094 Peoples R China Univ Chinese Acad Sci Coll Resources & Environm Beijing 100049 Peoples R China Univ North Texas Dept Geog & Environm Denton TX 76203 USA

Power corridor classification using LiDAR (light detection and ranging) point clouds is an important means for power line inspection. Many supervised classification methods have been used for classifying power corridor scenes, such as using random forest (RF) and JointBoost. However, these studies did not systematically analyze all the relevant factors that affect the classification, including the class distribution, feature selection, classifier type and neighborhood radius for classification feature extraction. In this study, we examine these factors using point clouds collected by an airborne laser scanning system (ALS). Random forest shows strong robustness to various pylon types. When classifying complex scenes, the gradient boosting decision tree (GBDT) shows good generalization. Synthetically, considering performance and efficiency, RF is very suitable for power corridor classification. This study shows that balanced learning leads to poor classification performance in the current scene. Data resampling for the original unbalanced dataset may not be necessary. The sensitivity analysis shows that the optimal neighborhood radius for feature extraction of different objects may be different. Scale invariance and automatic scale selection methods should be further studied. Finally, it is suggested that RF, original unbalanced class distribution, and complete feature set should be considered for power corridor classification in most cases.

关键词： airborne laser scanning power corridor classification class distribution feature selection random forest

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Investigation of the Mechanism of Heterovalent Codoping on the Scintillation Properties of GAGG:Ce Crystals

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CRYSTAL GROWTH & DESIGN 2024年第7期24卷 3002-3009页

作者： Zhang, Aochen Li, Chengyi Xue, Zhongjun Zhao, shuwen Qiu, peng Zhang, Zhe Zheng, Xiang Ding, Dongzhou Chinese Acad Sci Shanghai Inst Ceram Shanghai 201899 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China

Gd-3(Al,Ga)(5)O-12:Ce (GAGG:Ce) crystal is considered as one of the most efficient scintillators for nuclear medicine imaging devices and gamma detection applications due to its high light yield (58,000 ph./MeV), excellent energy resolution (4.9%@662 keV), and high density (6.63 g/cm(3)). With the introduction of time-of-flight techniques, scintillators are required to have a faster scintillation decay time and higher light yield. An efficient strategy for accelerating the scintillation decay process of GAGG:Ce is mainly through the codoping of low valence ions such as Ca2+. However, the mechanism of codoping has not yet been elucidated, and there is no reasonable explanation for the phenomenon of insignificant improvement in scintillation performance after codoping with some low-valence ions (e.g., Na+). To further investigate the effect of valence on the scintillation properties, three ions with different valence states (Mg2+, Yb3+, and Hf4+) are selected. The scintillation properties deteriorate after Hf4+ codoping, whereas the scintillation decay process is significantly accelerated after Mg2+ and Yb3+ codoping. In addition, the Mg2+ codoped crystal exhibits a low afterglow level. These excellent performances make it very promising for detector applications. Furthermore, the theoretical study of the luminescence mechanism provides a significant reference for the design of high-performance codoped GAGG:Ce crystals.

关键词： Crystals Ions Lattices Luminescence Particulate matter

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GLOSS RETENTIVE FLUOROCOPOLYMERS FOR COATING APPLICATIONS

GLOSS RETENTIVE FLUOROCOPOLYMERS FOR COATING APPLICATIONS

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作者： DUAN, Linlin JIANG, Wanchao XU, Gang ZHANG, Siyuan BANAVALI, Rajiv DING, Zhe peng, shuwen

标准号: EP3786238(A1)

Disclosed are protective coating compositions having enhanced gloss retention properties formed by steps comprising: (i) providing one or more fluorocopolymers by copolymerization of (1) one or more hydrofluoroolefin monomer(s) selected from the group consisting of hydrofluoroethylenes, hydrofluoropropenes, hydrofluorobutenes, hydrofluoropentenes and combinations of these, (2) one or more vinyl ester monomer(s), and (3) one or more vinyl ether monomer(s), wherein at least a portion of said vinyl ether monomer is a hydroxyl group-containing vinyl ether monomer, wherein the copolymer preferably has a number average molecular weight of greater than about 10,000;(ii) providing a VOC containing carrier for said one or more fluorocopolymers;and (iii) providing a stabilizing agent comprising: a) a radical scavenger and b) an absorber of UV light;and (iv) combining said one or more fluorocopolymers with said carrier and said stabilizing agent to produce a polymeric coating composition.

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Radiative forcing reduced by early twenty-first century increase in land albedo

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Nature 2025年第8065期641卷 1162-1171页

作者： Zhengyang Hou Liqiang Zhang Zhiqiang Xiao Ying Qu Duoying Ji Zidong Zhu Xin Yao shuwen peng Hao Geng Qihao Wang Suhong Liu Lanpu Zhao Zhaocong Wu Liangpei Zhang Jingjing peng Giovanni Forzieri Aolin Jia Jintai Lin Wenjie Fan Chenghu Zhou State Key Laboratory of Remote Sensing and Digital Earth Faculty of Geographical Science Beijing Normal University Beijing China Aerospace Information Research Institute Henan Academy of Sciences Zhengzhou China Earth System Science Interdisciplinary Center/Cooperative Institute for Satellite Earth System Studies (CISESS) University of Maryland College Park MD USA Department of Civil and Environmental Engineering University of Florence Florence Italy Remote Sensing and Natural Resource Modeling Department ERIN Luxembourg Institute of Science and Technology Belvaux Luxembourg Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beijing China Institute of Carbon Neutrality Peking University Beijing China School of Earth and Space Sciences Peking University Beijing China State Key Laboratory of Resources and Environmental Information System Institute of Geographical Science and Natural Resources Chinese Academy of Sciences Beijing China

Surface albedo greatly affects how much energy the Earth absorbs. Intensive human activities and accelerated climate change have altered surface albedo across spatial and temporal scales1,2,3, yet assessments of the effects of land use or land cover (LULC) and snow variations on land surface albedo are scarce at the global scale. As a result, the global land surface albedo dynamics over recent decades and their corresponding radiative forcing to the climate system remain poorly understood4,5,6,7,8,9. Here we quantify the individual and combined effects of snow cover dynamics, LULC conversions and non-conversion regions on albedo variations during 2001–2020 and estimate their induced radiative forcing. We show that the negative radiative forcing induced by the global land surface albedo change was −0.142 (−0.158, −0.114) W m−2over the past two decades. The global snow-free land surface albedo increased by 2.2% (P< 0.001), with a negative radiative forcing of −0.164 (−0.186, −0.138) W m−2(P< 0.001). The magnitude of this negative forcing is sevenfold larger than the positive forcing induced by snow dynamics, and equivalent to 59.9% of that caused by CO2emissions from 2011 to 201910. The global radiative forcing due to albedo changes in LULC non-conversion regions is 3.9 to 8.1 times greater than that from LULC conversions. The radiative forcing induced by albedo changes highlights the important role of land surface dynamics in modulating global warming.

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Theoretical Design of Broadband Tunable Nanograting-Coupled Fiber-Optic Surface Plasmon Resonance For Advanced Sensing

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2023年第2期41卷 761-767页

作者： Wei, Xinran Li, Rui Liang, Yuzhang Chu, shuwen Zhang, Xin Fang, Yurui peng, Wei Dalian Univ Technol Sch Phys Dalian 116024 Peoples R China Dalian Univ Technol Sch Optoelect Engn & Instrument Sci Dalian 116024 Peoples R China Dalian Univ Technol Liaoning Canc Hosp & Inst Canc Hosp Shenyang 110042 Peoples R China

Fiber-optic surface plasmon resonance (FOSPR) technology has drawn considerable attention to the label-free biosensing field. Currently, all FOSPR sensing devices capitalizing on flat plasmonic film are only performed on the fiber sidewalls, and demonstrated in a limited wavelength range, which is unfavorable to broaden their practical sensing application. Here, we develop and theoretically demonstrate an effective alternative for the realization of SPR on a flat gold film achieved on the end facet of optical fiber through the diffracting coupling of nanograting. This enables the consecutively adjustment of operating wavelength over a broad spectral range from visible (650 nm) to near-infrared light (1550 nm) through modulating the nanograting period. The sensing performances of the proposed nanograting-coupled FOSPR sensors with different specified resonance wavelengths are numerically investigated from two aspects of bulk refractive index and surface sensitivities. As a result, the highest bulk refractive index sensitivity of 1163 nm/RIU is obtained at the operating wavelength of 1550 nm and the optimal surface sensitivity is dependent on the location away from top surface of structure. The dependence of incident polarization direction on the sensing performances of the proposed structure are also explored. Due to the ease of adjustment of operating wavelength and compact integration on the end facet, this sensing platform can further extend the utility of FOSPR sensing technology in the practical application fields of disease diagnosis, environment monitoring, etc.

关键词： Sensors Surface waves Gold Optical surface waves Optical fiber sensors Electric fields Optical fiber polarization Biosensing metal nanostructure optical fiber surface plasmon resonance

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AlexNet for Image-Based COVID-19 Diagnosis

AlexNet for Image-Based COVID-19 Diagnosis

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International Conference on Medical Imaging and Computer-Aided Diagnosis, MICAD 2023

作者： Tang, Min peng, Yibin Wang, Shuihua Chen, shuwen Zhang, Yudong School of Physics and Information Engineering Jiangsu Second Normal University Nanjing211200 China Department of Biological Sciences Xi’an Jiaotong-Liverpool University Jiangsu Suzhou215123 China School of Computing and Mathematical Sciences University of Leicester LeicesterLE1 7RH United Kingdom Department of Information Technology Faculty of Computing and Information Technology King Abdulaziz University Jeddah21589 Saudi Arabia

ISBN: (纸本)9789819713349

The medical community is working harder to develop quick and accurate methods of diagnosing the virus in response to the COVID-19 pandemic. The speed and efficiency of image-based COVID-19 diagnosis are its benefits, but it also carries a risk of error and necessitates the involvement of numerous skilled radiologists. In this paper, a novel convolutional neural network architecture called AlexNet is presented. It has the capacity to automatically learn features in a hierarchy and recognize complex patterns and improves the model’s recognition of disease-related features. In addition, AlexNet’s adaptability and generalization capabilities contribute to its effectiveness in processing various imaging datasets. AlexNet therefore has great potential to identify complex patterns associated with COVID-19-related lung abnormalities. Nevertheless, it also has certain limitations, including the need for a large amount of processing power, the possibility of overfitting, the lack of sufficient interpretability, and the need for further development in order to make it more applicable to particular diagnostic tasks. In summary, collaborative efforts between the AI research community and healthcare professionals will continue to seek accurate, efficient, and ethical solutions for image-based COVID-19 diagnosis. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： COVID-19

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Interrogating the Effect of Block Sequence on Cocrystallization, Microphase Separation, and Charge Transport in All-Conjugated Triblock Copolymers

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MACROMOLECULES 2022年第17期55卷 7834-7844页

作者： Li, Lixin Zhan, Hao Chen, shuwen Zhao, Qingqing peng, Juan Fudan Univ Dept Macromol Sci State Key Lab Mol Engn Polymers Shanghai 200438 Peoples R China

Despite impressive progress in the research of all-conjugated diblock copolymers, there is a quite limited investigation into triblock counterparts. Moreover, regarding the block sequence, which is peculiar to triblock copolymers, its effect on their crystallization and microphase separation is still poorly understood. Herein, we design and synthesize a family of all-conjugated triblock copolymers comprising poly(3-butylthiophene) (P3BT), poly(3-hexylselenophene) (P3HS), and poly(3-dodecylthiophene) (P3DDT) of various block sequences, i.e., P3BT-b-P3DDT-b-P3HS, P3BT-b-P3HS-b-P3DDT, and P3HS-b-P3BT-b-P3DDT, elucidate the impact of the block sequence on their crystalline structures in conjunction by utilizing various solvents and thermal annealing, and investigate the charge transport properties of these different crystalline structures. Remarkably, the block sequence with the P3DDT block located in the central position (P3BT-b-P3DDT-b-P3HS) and faster solvent evaporation favor the cocrystals, while the P3DDT block situated at terminals (P3BT-b-P3HS-b-P3DDT and P3HS-b-P3BT-b-P3DDT), slower evaporation of the solvent, and heating lead to microphase separation over cocrystallization. Intriguingly, three different microphase-separated structures, which are correlated to the block sequence, are observed after high-temperature annealing (240 degrees C). Moreover, these various crystalline structures of triblock copolymers influence their charge mobilities in organic field-effect transistors (OFETs) closely. Thus, this work comprehensively elucidates the effect of the block sequence (intrinsic factor), solvent, and heating temperature (extrinsic factors) on the crystalline structure and electrical properties of conjugated triblock copolymers.

关键词： Annealing (metallurgy) Copolymers Crystal structure Crystallization Microphase

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The effect of Maillard reaction on flavour development of protein hydrolysates from cheese

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FOOD CHEMISTRY 2024年第Part1期437卷 137569页

作者： Gao, peng Zhang, Wenyuan Zhao, Xiaoxuan Xu, Chen Pang, Xiaoyang Fauconnier, Marie-Laure Zhang, shuwen Lv, Jiaping Chinese Acad Agr Sci Inst Food Sci & Technol Beijing 100193 Peoples R China Univ Liege Lab Chim Mol Nat LCMN Gembloux Agro Bio Tech 2 Passage Deportes B-5030 Gembloux Belgium Wageningen Univ & Res Food Qual & Design Grp Dairy Sci & Technol Wageningen Netherlands Chinese Acad Agr Sci Inst Anim Sci 2 Yuan Ming Yuan West Rd Beijing 100193 Peoples R China

This study aims to explore the effect of the Maillard reaction (MR) on flavour development of cheese protein hydrolysates. In addition, the effects of proteolysis, lipolysis, and the degreasing process on the MR have been explored. Cheese protein hydrolysates subjected to different treatments were heated with glucose and xylose, and their amino reactant components, colour parameters, and volatile compounds were determined. The results showed that the MR significantly affected the content of free amino acids, peptides, and volatile flavours of cheese protein hydrolysates. Peptides below 1500 Da and most of the free amino acids were the important amino reactants during the MR. 3-Ethyl-2,5-dimethylpyrazine, 2,5-dimethylpyrazine, 2-undecanone and 2-heptanone were the key volatile components of the MR products. The results also indicated that N-terminal amino acids of the peptide chain were easier to be reacted than C-terminal amino acids and thus produce a pyrazine-like flavour in the MR.

关键词： Maillard reaction Flavour development Degrease Lipolysis Peptidomics

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Equilibrium atmospheric boundary layer model for numerical simulation of urban wind environment

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PHYSICS OF FLUIDS 2024年第8期36卷

作者： Shen, Lian Han, Yan Cai, C. S. Hu, peng Lei, Xu Zhou, Pinhan Deng, shuwen Changsha Univ Sch Civil Engn Changsha 410022 Peoples R China Changsha Univ Sci & Technol Sch Civil Engn Changsha 410004 Peoples R China Southeast Univ Sch Transportat Nanjing 211189 Peoples R China Hunan Agr Univ Coll Water Resources & Civil Engn Changsha 410128 Peoples R China

The numerical simulation of urban wind environments faces difficulties in capturing the turbulent characteristics due to the large computational domain. Traditional Reynolds-averaged methods (RANS) can effectively capture the average wind characteristics of urban areas. However, due to the significant dissipation and attenuation of turbulent energy in the downstream direction, this method fails to provide accurate turbulent characteristics after time-averaging processing. Therefore, in order to obtain a higher-precision turbulent wind field distribution within urban areas, this paper proposed a new numerical method named an equilibrium atmospheric boundary layer model (EABL) by modifying the control equation of the shear stress transport k-omega model. During the process, the equilibrium atmospheric boundary layer was achieved successfully, and the attenuation problem of the turbulent kinetic energy and dissipation rate during the computational fluid dynamics numerical simulation was resolved. Simultaneously, a wind tunnel experiment and six turbulence models [standard k-epsilon, realizable k-epsilon, renormalization group k-epsilon, large eddy simulation-narrowband synthesis random flow generator (LES-NSRFG) and LES vortex method and EABL] were employed to simulate the wind field characteristics in an actual residential area. The simulation results demonstrate that, relative to traditional RANS models, the EABL model enhances the simulation accuracy of turbulence characteristics by over two times. Furthermore, compared to LES models, the EABL model can reduce computational time by threefold.

关键词： Kinetic energy

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