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Highly efficient silicon light emitting diodes produced by doping engineering

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Frontiers of Optoelectronics 2012年第1期5卷 7-12页

作者： Jiaming SUN M.HELM W.SKORUPA B.SCHMIDT A.MVCKLICH Key Laboratory of Weak Light Nonlinear Photonics Ministry of Education Nankai UniversityTianjin 300071China institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-RossendorfDresden 01314Germany

This paper reviews our recent progress on silicon （Si） pn junction light emitting diodes with locally doping engineered carrier potentials. Boron implanted Si diodes with dislocation loops have electroluminescence （EL） quantum efficiency up to 0.12%, which is two orders of magnitude higher than those without dislocations. Boron gettering along the strained dislocation lines produces locally p-type spike doping at the dislocations, which have potential wells for bounding spatially indirect excitons. Thermal dissociation of the bound excitons releases free carriers, leading to an anomalous increase of the band to band luminescence with increasing tempera- ture. Si light emitting diodes with external quantum efficiency of 0.2% have been also demonstrated by implementation of pnpn modulation doping arrays.

关键词： silicon (Si) light emitting diodes dopingengineering dislocation modulation doping

Temperature-driven phase transformation and element segregation in Pd-Ru immiscible alloy nanoparticles:Spatial resolving of elements and insights for electrocatalysis

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Nano Research 2023年第7期16卷 9968-9976页

作者： Hui Li Zheng Hu Yu Zhang Wenbo Zhao Yuyao Zeng Wei Zhou Shi Hu Department of Chemistry School of ScienceTianjin Key Laboratory of Molecular Optoelectronic ScienceTianjin UniversityTianjin 300072China institute of Energy Hefei Comprehensive National Science CenterHefei 230031China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China Department of Physics School of ScienceTianjin Key Laboratory of Molecular Optoelectronic ScienceTianjin UniversityTianjin 300072China

Bimetallic alloys could form three typical structures including solid solution,heterostructure,and intermetallic compound,depending on the interactions between identical and different *** the trend can be predicted by the types of binary phase diagram,different synthetic protocols will trap the system in various kinetic intermediates among the three typical ***,we studied the phase evolution and elemental segregation in the alloy nanoparticles of immiscible Pd-Ru before and after thermal *** developing an analysis method of local element segregation(LES)based on the energy dispersive spectroscopy(EDS)mapping signals,we were able to quantify the mixing of Pd and Ru atoms during the gradual phase transition from face-centered cubic(fcc)to hexagonal close packed(hcp).Density functional theory was also applied to calculate the energies of all possible PdRu4 structures(93 fcc models and 267 hcp models),which helps to rationalize the phase transition and element *** annealing process also leads to the change of the electronic structure,which further influences the performance in the electrocatalytic hydrogen evolution *** highest activity of PdRu4-400 was largely attributed to the proper interface between the Pd-rich fcc phase and Ru-rich hcp phase,as revolved by the above methods.

关键词： Pd-Ru alloy short-range order local element segregation hydrogen evolution reaction

Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions

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Science China Earth Sciences 2006年第2期49卷 193-201页

作者： LEI Tingwu1,2, LIU Han1, PAN Yinghua3, ZHAO Jun2, ZHAO Shiwei2 & YANG Yonghui2 1. The Key Laboratory of modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineer-ing, China Agricultural university, Beijing 100083, China 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, institute of Soil and Water Conservation, Yangling 712100, China 3. Geographic and Resources Management College, Yantai Normal university, Yantai 264025, China The Key Laboratory of modern Precision Agriculture System Integration Research College of Hydraulic and Civil Engineering China Agricultural University Beijing China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Yangling China Geographic and Resources Management College Yantai Normal University Yantai China

The soil infiltrability of hill-slope is important to such studies andpractices as hydrological process, crop water supply, irrigation practices, and soil erosion. A newmethod for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-outwas advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimatedfrom the advances of runoff on soil surface and the water running out of the slope were *** of 2 cases were conducted. Case Ⅰ was done under a rainfall intensity of 20 mm/h, at aslope gradient of about 0° with a runoff/on length (area) ratio of 1 : 1. Case Ⅱ was under arainfall intensity of 60 mm/h and a slope of 20° with a runoff/on length (area) ratio of 1 : *** ring method was also used to measure the infiltrability for comparison purposes. Theexperiments were done with soil moisture of 10%. Required data were collected from laboratoryexperiments. The infiltrability curves were computed from the experimental data. The resultsindicate that the method can well conceptually represent the transient infiltrability process, withcapability to simulate the very high initial soil infiltrability. The rationalities of the methodand the models were validated. The errors of the method for the two cases were 1.82%/1.39% and4.49%/3.529% (Experimental/Model) respectively, as estimated by comparing the rainfall amount withthe infiltrated volume, to demonstrate the accuracy of the method. The transient and steadyinfiltrability measured with double ring was much lower than those with this new method, due towater supply limit and soil aggregates breaking down at initial infiltration stage. The method canovercome the short backs of the traditional sprinkler method and double ring method for soilinfil-traility. It can be used to measure the infiltrability of sloped surface underrainfall-runoff-erosion conditions, in the related studies.

关键词： Infiltrability, runoff-on-out, rainfall, sloped surface, model.

Synthesis of MoX2 (X =Se or S) monolayers with high-concentration 1T'phase on 4H/fcc-Au nanorods for hydrogen evolution

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Nano Research 2019年第6期12卷 1301-1305页

作者： Zhengqing Liu Xiao Zhang Yue Gong Qipeng Lu Zhicheng Zhang Hongfei Cheng Qinglang Ma Junze Chen Meiting Zhao Bo Chen Ye Chen Xue-Jun Wu Pengfei Yin Lin Gu Yaping Du Hua Zhang School of Materials Science and Engineering & National institute for Advanced Materials Nankai UniversityTianjin 300350China Center for Programmable Materials School of Materials Science and EngineeringNanyang Technological University50 Nanyang AvenueSingapore 639798Singapore Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Collaborative Innovation Center of Quantum Matter Beijing 100190China

Controlled synthesis of transition metal dichalcogenide (TMD) monolayers with unusual crystal phases has attracted increasing attention due to their promising applications in ***,the facile and large-scale preparation of TMD monolayers with high-concentration unusual crystal phase still remains a ***,we report the synthesis of MoX2 (X =Se or S) monolayers with high-concentration semimetallic 1T'phase by using the 4H/face-centered cubic (fcc)-Au nanorod as template to form the 4H/fcc-Au@MoX2 *** concentrations of 1T'phase in the prepared MoSe2 and MoS2 monolayers are up to 86% and 81%,*** a proof-of-concept application,the obtained Au@MoS2 nanocomposite is used for the electrocatalytic hydrogen evolution reaction (HER) in acid medium,exhibiting excellent performance with a low overpotential of 178 mV at the current density of 10 mNcm^2,a small Tafel slope of 43.3 mV/dec,and excellent HER *** work paves a way for direct synthesis of TMD monolayers with high-concentration of unusual crystal phase for the electrocatalytic application.

关键词： MoS2 monolayers semimetallic 1T'phase 4H/face-centered cubic (fcc)-Au nanorods hydrogen evolution

Intra-Ring Bridging:A Strategy for Molecular Design of Highly Energetic Nitramines

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Chinese Journal of Chemistry 2021年第10期39卷 2857-2864页

作者： Linyuan Wen Tao Yu Weipeng Lai Jinwen Shi Maochang Liu Yingzhe Liu Bozhou Wang State Key Laboratory of Fluorine&Nitrogen Chemicals Xi'an Modern Chemistry Research InstituteXi'anShaanxi710065 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'anShaanxi 710049China

Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic scaffolds is *** this work,we propose an intra-ring bridging strategy inspired by the known energetic nitramines to design novel polycyclic and cage energetic *** than 100 energetic structures were designed by introducing the C—C bridges and increasing the ring *** synthesis difficulty is considered besides the two most concerned properties of EMs,energy and *** a comprehensive estimation,a symmetric cage molecule labeled as 8U-30 was finally selected because of its relatively high detonation performance,and comparable impact sensitivity as well as synthetic accessibility with ***,the proposed strategy could be utilized in further molecular design to gain various scaffolds,especially cage structures,for different demands.

关键词： Molecular modeling Energetic materials Cage compounds Computational chemistry Nitramines

A small electron beam ion trap/source facility for electron/neutral-ion collisional spectroscopy in astrophysical plasmas

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Research in Astronomy and Astrophysics 2018年第1期18卷 1-10页

作者： Gui-Yun Liang Hui-Gang Wei Da-Wei Yuan Fei-Lu Wang Ji-Min Peng Jia-Yong Zhong Xiao-Long Zhu Mike Schmidt Günter Zschornack Xin-Wen Ma Gang Zhao Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Department of Astronomy Beijing Normal University Beijing 100875 China institute of modern Physics Chinese Academy of Sciences Lanzhou 730000 China DREEBIT GmbH 01109 Dresden Germany

Spectra are fundamental observation data used for astronomical research,but understanding them strongly depends on theoretical models with many fundamental parameters from theoretical *** models give different insights for understanding a specific ***,laboratory benchmarks for these theoretical models become *** electron beam ion trap is an ideal facility for spectroscopic benchmarks due to its similar conditions of electron density and temperature compared to astrophysical plasmas in stellar coronae,supernova remnants and so *** this paper,we will describe the performance of a small electron beam ion trap/source facility installed at National Astronomical Observatories,Chinese Academy of *** present some preliminary experimental results on X-ray emission,ion production,the ionization process of trapped ions as well as the effects of charge exchange on the ionization.

关键词： X-ray:general atomic processes line:formation method:laboratory:atomic

New approach to extract phase feature of 3-D objects by wavelength-scanning digital holography

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Optoelectronics Letters 2006年第2期2卷 136-138页

作者： SHEN Jin-yuan LI Xian-guo M. K. Kim CHANG Sheng-jiang College of Information Engineering Zhengzhou UniversityZhengzhou 450052China Department of Physics University of South Florida Tampa Florida 33620 USA Key Laboratory of Opto-electronics Information Technical Science EMC Institute of Modern Optics Nankai UniversityTianjin 300071 China

A new approach to extract phase feature of 3-D objects based on wavelength-scanning digital holography and numerical reconstruction technique is proposed in this paper.A number of holograms are recorded on a digital camera and reconstructed numerically by a computer with different wavelengths spaced at regular *** theoretical analysis and computer simulations demonstrate that those pixels with the same phase of a 3-D object can focus on the same reconstruction *** those pixels with different phase of a 3-D object focus on the different reconstruction *** the phase information of a 3-D object can be described by a series of reconstructed images on different planes.

关键词：数字全息术波长扫描数字相机三维重建

Molecular Axis Orientation in Charge Transfer Reactions Determined with a Reaction Microscope

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Chinese Journal of Chemical Physics 2009年第6期22卷 621-626,J0002页

作者： Shao-feng Zhang Xin-wen Ma Xiao-long Zhu institute of modern Physics Chinese Academy of Sciences Lanzhou 730000 China Graduate university of Chinese Academy of Sciences Beijing 100049 China

Based on the reaction microscope at the institute of modern physics, the reaction mechanism in molecular ion-atom collisions is investigated experimentally. The features of this system is illustrated by a kinematically complete experhnent performed for the collision process. Using the so-called list-mode data recording technique and the coincidence measurement, the momentum vector of each fragment from the molecular ion were recorded event by event. The orientation of the molecular axis for H2^＋ dissociation reactions could be determined for each event in the off-line analysis. The measured orientation of the molecular ion is believed the same as the one at the instance of collision under axial recoil approximation. The polar angle resolution of the molecular orientation of ±8° was obtained.

关键词： Reaction microscope Imaging technique Molecular orientation Hydrogen molecular ion Dissociation

Lifetime of Doubly Charmed Baryons

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Communications in Theoretical Physics 2008年第4期49卷 993-1000页

作者： CHANG Chao-Hsi LI Tong LI Xue-Qian WANG Yu-Ming CCAST （World Laboratory） P.O. Box 8730 Beijing 100080 China institute of Theoretical Physics the Chinese Academy of Sciences P.O. Box 2735 Beijing 100080 China Department of Physics Nankai University Tianjin 300071 China institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918 Beijing 100049 China

In this work, we evaluate the lifetimes of the doubly charmed baryons Ξcc^＋ ,Ξcc^＋＋, and Ωcc^＋. We carefully calculate the non-spectator contributions at the quark level, where the Cabibbo-suppressed diagrams are also included. The hadronic matrix elements are evaluated in the simple non-relativistic harmonic oscillator model. Our numerical results are generally consistent with that obtained by other authors who used the diquark model. However, all the theoretical predictions on the lifetimes are one order larger than the upper limit set by the recent SELEX measurement. This discrepancy would be clarified by the future experiment. If more accurate experiment still confirms the value of the SELEX collaboration, there must be some unknown mechanism to be explored.

关键词： doubly charmed baryons harmonic oscillator model