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Identifying defect energy levels using DLTS under different electron irradiation conditions

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Nuclear Science and Techniques 2017年第12期28卷 262-268页

作者： Chun-Sheng Guo Ruo-Min Wang Yu-Wei Zhang Guo-Xi Pei Shi-Wei Feng zhao-xian li College of Electronic Information and Control Engineering Beijing University of TechnologyBeijing 100124China Wuxi EL Pont Group Wuxi 214151China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Electron beams of 0.5, 1.5, 2.0, and 5.0 MeV were used to irradiate n-Si diodes to fluences of5.5×10^(13), 1.7×10^(14), and 3.3×1014 e cm^(-2). The forward voltage drop, minority carrier lifetime, and deep level transient spectroscopy(DLTS) characteristics of silicon p–n junction diodes before and after irradiation were compared. At the fluence of 3.3×10^(14) e cm^(-2), the forward voltage drop increased from 1.25 V at 0.5 MeV to 7.96μs at 5.0 MeV, while the minority carrier lifetime decreased significantly from 7.09 ls at 0.5 MeV to 0.06μs at 5.0 MeV. Six types of changes in the energy levels in DLTS spectra were analyzed and discussed.

关键词： Electron irradiation Deep level transient spectroscopy (DLTS) Minority carrier life time Silicon diode

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玉米干物质分配与发育进程关系的干旱响应

中国农业气象 2024年第7期45卷 729-744页

作者：蔡福米娜明惠青张慧张淑杰赵先丽金晨张玉书中国气象局沈阳大气环境研究所沈阳110166 辽宁省农业气象灾害重点实验室沈阳110166 辽宁省气象服务中心沈阳110166 辽宁省锦州市生态与农业气象中心锦州121001

为深入了解玉米干物质分配(DMP)随发育进程(DVS)的变化及其对干旱的响应机理,并完善玉米DMP参数化方案,基于锦州地区开展4a的玉米营养(VP)和生殖(RP)生长期干旱试验,研究‘丹玉405’和‘先玉335’两个品种玉米地上各器官干物质积累和分... 详细信息

为深入了解玉米干物质分配(DMP)随发育进程(DVS)的变化及其对干旱的响应机理,并完善玉米DMP参数化方案,基于锦州地区开展4a的玉米营养(VP)和生殖(RP)生长期干旱试验,研究‘丹玉405’和‘先玉335’两个品种玉米地上各器官干物质积累和分配随玉米发育进程的变化及其对干旱的响应特征。结果表明:正常生长情况下,玉米的果穗干重与地上总干重随DVS递增的趋势相似,叶和茎干重随DVS都表现出先增后减趋势;玉米叶干物质分配系数(DMPR)随DVS线性或指数减小,茎DMPR随DVS先增大后减小,最大值出现在开花吐丝期,果穗DMPR随DVS线性增大;叶干物质增长量分配系数(IDMPR)随DVS减小,在乳熟期发生干物质再分配,茎和果穗IDMPR与DVS都呈先增后减的变化特征,茎干物质再分配略晚于叶。土壤干旱情况下,各器官干重随干旱加重而减小;各器官DMPR比干重对干旱的响应偏小且偏晚,其中‘丹玉405’的叶和茎DMPR在玉米生长后期随干旱的加重及发生时间的延后而增大,果穗DMPR的响应与之相反,‘先玉335’各器官DMPR对干旱的响应弱于‘丹玉405’。不同时期干旱使叶、茎和果穗IDMPR较正常值分别偏小、偏大和偏小,叶干物质再分配时间提前。高温和干旱叠加可导致玉米果穗生长停滞,使叶和茎的干物质再分配受到严重抑制,导致DMPR和干重比正常值明显偏大。综合4a试验结果,玉米的干物质积累和DMP随DVS变化及对干旱的响应都表现出明显的种间差异,干旱响应与干旱程度及其发生阶段关系密切。

关键词：玉米干旱响应干物质积累干物质分配发育进程

Exploring the Interplay between Local Chain Structure and Stress Distribution in Polymer Networks

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Chinese Journal of Polymer Science 2024年第6期42卷 874-885页

作者： Jin-Tong Xue Yang Bai li Peng xian-Bo Huang zhao-Yan Sun School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China National-certified Enterprise Technology Center Kingfa Science and Technology Co.Ltd.Guangzhou510663China

The mechanical behavior of polymer networks is intrinsically correlated with the local chain topology and chain *** this study,we delve into this relationship through the lens of coarse-grained molecular dynamics(CG-MD)*** aim is to illuminate the intricate interplay between local topology and stress distribution within polymer monomers,cross-linkers,and various components with distinct cross-link connections,thereby elucidating their collective impact on the mechanical properties of polymer *** mainly focus on how specific local structures contribute to the overall mechanical response of the *** particular,we employ local stress analysis to unravel the mechanics of these *** findings reveal the diverse responses of individual components,such as junctions,strands,cross-linkers between junctions,and dangling chain ends,when subjected to ***,we observe that these components exhibit varying degrees of deformation tolerance,underscoring the significance of their roles in determining the mechanical characteristics of the *** investigations highlight junctions as primary contributors to stress accumulation,and particles with higher local stress showing a stronger correlation between stress and Voronoi ***,our results indicate that both strands and cross-linkers between junctions exhibit heightened stress levels as strand lengths *** study enhances our understanding of the multifaceted factors governing the mechanical attributes of cross-linked polymer systems at the microstructural level.

关键词： Local chain structure Local stress Molecular dynamics simulation

Quantum dot-enabled infrared hyperspectral imaging with single-pixel detection

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light(Science & Applications) 2024年第6期13卷 1112-1121页

作者： Heyan Meng Yuan Gao Xuhong Wang xianye li lili Wang xian zhao Baoqing Sun School of Information Sciences and Engineering Shandong UniversityQingdaoChina Center for Optics Research and Engineering(CORE) Key Laboratory of Laser&Infrared System(Shandong University)Ministry of EducationShandong UniversityQingdaoChina School of Mechanical Electrical and Information EngineeringShandong UniversityWeihaiChina

Near-infrared(NIR)hyperspectral imaging is a powerful technique that enables the capture of three-dimensional(3D)spectra-spatial information within the NIR spectral range,offering a wide array of ***,the high cost associated with InGaAs focal plane array(FPA)has impeded the widespread adoption of NIR hyperspectral *** this challenge,in this study,we adopt an alternative approach—single-pixel detection for NIR hyperspectral *** investigation reveals that single-pixel detection outperforms conventional FPA,delivering a superior signal-to-noise ratio(SNR)for both spectral and imaging *** implement this strategy,we leverage self-assembled colloidal quantum dots(CQDs)and a digital micromirror device(DMD)for NIR spectral and spatial information multiplexing,complemented by single-pixel detection for simultaneous spectral and image *** experimental results demonstrate successful NIR hyperspectral imaging with a detection window about 600 nm and an average spectral resolution of 8.6 nm with a pixel resolution of 128×*** resulting spectral and spatial data align well with reference instruments,which validates the effectiveness of our *** circumventing the need for expensive and bulky FPA and wavelength selection components,our solution shows promise in advancing affordable and accessible NIR hyperspectral imaging technologies,thereby expanding the range of potential applications.

关键词： spectral Quantum mirror

Dual polarization strategy to enhance CH_(4) uptake in covalent organic frameworks for coal-bed methane purification

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Chinese Chemical Letters 2024年第8期35卷 545-548页

作者： Junhua Wang Xin lian Xichuan Cao Qiao zhao Baiyan li xian-He Bu School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221116China School of Chemical Engineering and Technology China University of Mining and TechnologyXuzhou 221116China School of Materials Science and Engineering National Institute for Advanced MaterialsTKL of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin 300350China

The purification of low-grade coal-bed methane is extremely important,but challenging,due to the very similar physical properties of CH_(4)and ***,we proposed a dual polarization strategy by employing triazine and polyfluoride sites to construct polar pores in COF materials,achieving the efficient separa-tion of CH_(4)from *** expected,the dual polarized F-CTF-1 and F-CTF-2 exhibit higher CH_(4)adsorption capacity and CH_(4)/N_(2)selectivity than CTF-1 and CTF-2,***,the CH4 uptake capacity and CH_(4)/N_(2)selectivity of F-CTF-2 is 1.76 and 1.42 times than that of *** work not only developed promising COF materials for CH4/N_(2)separation,but also provided important guidance for the separation of other adsorbates with similar properties.

关键词： Dual polarization strategy Covalent organic frameworks(COFs) Coal-bed methane purification Chemical/thermal stability Cycling stability

Exosome-Transmitted miR-224-5p Promotes Colorectal Cancer Cell Proliferation via Targeting ULK2 in p53-Dependent Manner

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Biomedical and Environmental Sciences 2024年第1期37卷 71-84页

作者： YANG Le Mei ZHENG Qi liU Xiao Jia li xian xian Veronica lim CHEN Qi zhao Zhong Hua WANG Shu Yang Department of Pathology School of Basic MedicineFudan UniversityShanghai 200032China Department of Pathology Dunedin School of MedicineUniversity of OtagoDunedin 9054New Zealand Department of Pathology Huashan HospitalFudan UniversityShanghai 200040China Shanghai Cancer Institute Renji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200127China Teladoc Health Inc Shanghai 200335China Shanghai Medical College Fudan UniversityShanghai 200032China Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention Shanghai 200032China

Objective To investigate the role and molecular mechanism of exosomal miR-224-5p in colorectal cancer(CRC).Methods The miR-224-5p expression in CRC patient tissues and cell-derived exosomes was measured by laser capture microdissection and qRT-PCR,***-luciferase reporter gene assay was used to determine the target gene of *** protein expressions of p53 and unc-51 like kinase 2(ULK2)in CRC cells were detected by western *** cytometry was used to detect cell cycle and *** proliferation was measured by CCK8 and EdU *** The miR-224-5p expression was upregulated in CRC tissues and increased progressively with the rise of CRC *** cells secreted extracellular miR-224-5p mainly in an exosome-dependent manner,and then miR-224-5p could be transferred to surrounding tumor cells to regulate cell proliferation in the form of autocrine or ***,ULK2 was characterized as a direct target of miR-224-5p and was downregulated in CRC ***,ULK2 inhibited CRC cell proliferation in a p53-dependent ***,exosome-derived miR-224-5p partially reversed the proliferation regulation of ULK2 on CRC *** Our findings demonstrate that exosome-transmitted miR-224-5p promotes p53-dependent cell proliferation by targeting ULK2 in CRC,which may offer promising targets for CRC prevention and therapy.

关键词： miR-224-5p Exosome ULK2 p53 Cell proliferation Colorectal cancer

Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni_(3)S_(2) as Efficacious Bi-Functional Electrocatalysts for Concurrent H_(2) Evolution and Methanol Selective Oxidation

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Nano-Micro Letters 2024年第4期16卷 415-431页

作者： Qianqian zhao Bin zhao Xin Long Renfei Feng Mohsen Shakouri Alisa Paterson Qunfeng Xiao Yu Zhang xian‑Zhu Fu Jing‑li Luo Shenzhen Key Laboratory of Energy Electrocatalytic Materials Shenzhen Key Laboratory of Polymer Science and TechnologyGuangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China Canadian light Source Inc. SaskatoonSK S7N 0X4Canada Instrumental Analysis Center of Shenzhen University(lihu Campus) Shenzhen UniversityShenzhen 518055People’s Republic of China

Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO_(2) emission. Herein, the hetero-nanocrystals between monodispersed Pt(~ 2 nm) and Ni_(3)S_(2)(~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H_(2) generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni_(3)S_(2) could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH_(3)OH to formate is accomplished at very low potentials(1.45 V) to attain 100 m A cm^(-2) with high electronic utilization rate(~ 98%) and without CO_(2) emission. Meanwhile, the Pt–Ni_(3)S_(2) can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction(HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction(MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 m A cm^(-2) with good reusability.

关键词： Dual-monodispersed heterostructure Electronic interactive modulation Reaction mechanism Methanol oxidation reaction Hydrogen generation

Three-stage niobium mineralization at Bayan Obo, China

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National Science Review 2024年第4期11卷 102-110页

作者： Yan Yu Yang li Yu liu Xiao-Xiao ling li-Guang Wu li Yang Lan Yang Bo Yang Yong-Gang zhao xian-Hua li State Key Laboratory of lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences College of Earth and Planetary Science University of Chinese Academy of Sciences Ministry of Education Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking University Mining Research Institute Baotou Iron and Steel(Group) Co.LTD State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization

The Chinese Bayan Obo deposit is a world-class rare earth element(REE) deposit with considerable niobium(Nb) and iron(Fe) resources. A complete genetic understanding on all metals is fundamental for establishing genetic models at Bayan Obo. With extensive research being focused on REE enrichment, the timing and controls of Nb enrichment remain unresolved at Bayan Obo, which is mainly due to the challenges in dating, i.e. multistage thermal events, fine-grained minerals with complex textures and the rare occurrence of uranium-enriched minerals with mature dating methods. Based on robust geological and petrographic frameworks, here we conducted ion probe uranium-lead(U-Pb) dating of ferrocolumbite to unravel the timing, hence the genesis of Nb mineralization. Three types of hydrothermal ferrocolumbites—key Nb-bearing minerals—are identified based on their textures and mineral assemblages. They yield U-Pb ages of 1312 ± 47 Ma(n = 99), 438 ± 7 Ma(n = 93), and 268 ± 5 Ma(n = 19), respectively. In line with deposit geology, we tentatively link the first, second and third stage Nb mineralization to Mesoproterozoic carbonatite magmatism, ubiquitous early Paleozoic hydrothermal activity, and Permian granitic magmatism, respectively. While quantifying the contribution of metal endowment from each stage requires further investigation, our new dates highlight that multi-stage mineralization is critical for Nb enrichment at Bayan Obo, which may also have implications for the enrichment mechanism of Nb in REE deposits in general.

关键词： niobium mineralization U-Pb dating ferrocolumbite Bayan Obo

Comparative analysis of the characteristics of outlet short circuit and winding insulation fault of distribution transformer and its preventive measures

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High Voltage 2024年第3期9卷 700-709页

作者： Richang xian Yuyao Hu Bingqian Zhang Qingyu Rong Rujie zhao Wei Wang Yang Guo Yunhao li College of Electrical and Electronic Engineering Shandong University of TechnologyZiboChina State Grid of China Technology College JinanChina Shandong Huineng Electric Co. Ltd.ZiboChina

Outlet short circuit on the low-voltage(LV)side and winding inter-turn short circuit faults are hazardous to transformer *** investigate the formation mechanism of winding insulation faults of distribution transformer,ANSYS Maxwell was used to build a coupled magnetic field-circuit model with the same structural dimension as the actual distribution *** outlet short circuit and winding inter-turn insulation faults were set by using the voltage-controlled switch in the external circuit of the ***-sequently,the differences in the electromagnetic characteristics and the electrodynamic force distributions of the windings under three operating conditions,namely,nominal load,three-phase outlet short circuit on the LV side and inter-turn insulation failure were studied,*** results show that compared with the rated load,in the cases of outlet short circuit and inter-turn insulation faults,the amplitude of winding current in-creases by 20 and 50 times,the magnetic field strength grows by 20 and 17 times,and the electrodynamic force rises by 400 and 230 times,*** short circuit fault is more likely to cause the winding instability and deformation,and inter-turn short circuit fault can easily burn out winding ***,corresponding preventive measures were proposed.

关键词： fault characteristics winding