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Property Changes of Gamma-Ray Bursts

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Chinese Physics Letters 1996年第8期13卷 637-640页

作者： LI ti-pei Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039

From analysing the third burst and transient source experiment gamma-ray burst catalog,systematic variations of average observational characteristics ofγ-ray bursts(GRBs)with a time scale of months to years are revealed,which raise a difficulty to existing models and indicate an origin of GRBs,at least partly,within the heliosphere.A possible GRB producing process is discussed.

关键词： difficulty transient origin

Electronic structure and optical properties of Ge-and F-doped α-Ga2O3:First-principles investigations

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Chinese Physics B 2020年第12期29卷 402-407页

作者： ti-Kang Shu Rui-Xia Miao san-Dong Guo Shao-Qing Wang Chen-He Zhao Xue-Lan Zhang School of Electronic Engineering Xi’an University of Posts&TelecommunicationsXi’an 710121China

The prospect ofα-Ga2O3 in optical and electrical devices application is *** order to obtain better performance,Ge and F elements with similar electronegativity and atomic size are selected as *** on density functional theory(DFT),we systematically research the electronic structure and optical properties of dopedα-Ga2O3 by GGA+U calculation *** results show that Ge atoms and F atoms are effective n-type *** Ge-dopedα-Ga2O3,it is probably obtained under O-poor ***,for F-dopedα-Ga2O3,it is probably obtained under O-rich *** doping system of F element is more stable due to the lower formation *** this investigation,it is found that two kinds of doping can reduce theα-Ga2O3 band gap and improve the *** is more,it is observed that the absorption edge after doping has a blue shift and causes certain absorption effect on the visible *** the whole scale of comparison,Ge doping is more suitable for the application of transmittance materials,yet F doping is more appropriate for the application of deep ultraviolet *** expect that our research can provide guidance and reference for preparation ofα-Ga2O3 thin films and photoelectric devices.

关键词： DFT GGA+U calculation method α-Ga2O3 doping

Implementing VLPR systems based on TMS320DM642

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第12期8卷 2005-2016页

作者： ZHU Le-qing ZHANG san-yuan YE Xiu-zi School of Computer Science and Technology Zhejiang University Hangzhou 310027 China

This paper gives a practical schema for using DSP boards to construct Vehicle License Plate Recognition (VLPR) modules that could be embedded in any Intelligent Transportation System (ITS). Using DSP can avoid the heavy investment in dedicated VLPR system and improve the computational power compared to PC software environment. Low cost, high computational power, and high flexibility of DSP provide the License Plate Recognition System (LPRS) an excellent cost-effective solution to execute the major part of the recognition tasks. This paper describes a successful implementation of VLPR system based on Texas Instruments (ti)'s TMS320DM642. The DSP board acquires video (which could be output to a monitor for surveillance) from a camera, captures images from the video, locates and recognizes the license plates in images, and then sends the recognized results and related images after compression to a host PC through the network. Finally, the overall software is optimized according to the features of DM642 chip. Experiments showed that the DSP VLPR system performs well on the local license plates, and that the processing speed and accuracy can meet the requirement of practical applications.

关键词： License Plate Recognition (LPR) Embedded system Image processing DSP DM642

Synergistic etching and intercalation enables ultrathin ti_(3)C_(2)T_(x)and Nb_(2)CT_(x)MXene nanosheets

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Rare Metals 2023年第4期42卷 1175-1185页

作者： Qian-Qian Xiong Tahir Muhmood Cheng-Xiao Zhao Jing-san Xu Xiao-Fei Yang College of Science Nanjing Forestry UniversityNanjing210037China School of Chemistry and Physics Science and Engineering FacultyQueensland University of TechnologyBrisbaneQLD4001Australia

Transition metal-containing MXene has shown great potential in the promising research fields,and its performance strongly depends on the composition,structure,dimension,and surface ***,rational design and controllable synthesis of ultrathin two-dimensional(2D)MXene nanosheets with uniform surface terminations are of great ***,the use of 2D MXene,particularly in solar-powered photocatalysis and electrocatalysis,is restricted by the formation of thick,multi-layered MXene flakes with a small interlayer spacing produced from the conventional hydrofluoric acid(HF)etching *** this work,we report a few-layer MXene nanosheets by solely employing a mixture of lithium fluoride and hydrochloric acid as the etching *** etching and intercalation technique endows MXene with ultrathin 2D nanostructures;moreover,the use of fluoride salt,rather than harmful HF,offers a safer and environmentally-friendly synthetic route for scalable green production of 2D *** the obtained ti_(3)C_(2)T_(x)and Nb_(2)CT_(x)nanosheets show a highly efficient photoelectrochemical performance superior to highly stacked MXene *** work highlights a mild,simultaneous etching and delamination strategy for the development of high quality of 2D MXene nanosheets.

关键词： MXene Electrocatalysis Hydrogen evolution reaction(HER) Two-dimensional(2D)nanomaterials

A neutron diffraction investigation of high valent doped barium ferrite with wideband tunable microwave absorption

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Journal of Advanced Ceramics 2022年第2期11卷 263-272页

作者： Jun LI Yang HONG san HE Weike LI Han BAI Yuanhua XIA Guangai SUN Zhongxiang ZHOU School of Physics Harbin Institute of TechnologyHarbin 150001China Heilongjiang Provincial Key Laboratory of Plasma Physics and Application Technology Harbin Institute of TechnologyHarbin 150001China School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory for Neutron Physics of CAEP Institute of Nuclear Physics and ChemistryMianyang 621999China

The barium ferrite Bati_(x)Fe_(12−x)O_(19)(x=0.2,0.4,0.6,0.8)(BFTO-x)ceramics doped by ti4+were synthesized by a modified sol–gel *** crystal structure and magnetic structure of the samples were determined by neutron diffraction,and confirm that the BFTO-x ceramics were high quality single phase with sheet *** x increasing from 0.2 to 0.8,the saturation magnetization(M_(s))decreases gradually but the change trend of coercivity(H_(c))is complex under the synergy of the changed grain size and the magnetic crystal anisotropy *** on the high valence of ti^(4+),double resonance peaks are obtained in the curves of the imaginary part of magnetic conductivity(μ′′)and the resonance peaks could move toward the low frequency with the increase of x,which facilitate the samples perform an excellent wideband modulation microwave absorption *** the x=0.2 sample,the maximum reflection loss(RL)can reach−44.9 dB at the thickness of only 1.8 mm,and the bandwidth could reach 5.28 GHz at 2 mm when RL is less than−10 *** the BFTO-x ceramics show excellent frequency modulation ability varying from 18(x=0.8)to 4 GHz(x=0.4),which covers 81%of the investigated frequency in microwave absorption *** work not only implements the tunable of electromagnetic parameters but also broadens the application of high-performance microwave absorption devices.

关键词： barium ferrite neutron diffraction microwave absorption

Effect of atorvastatin on expression of TLR4 and NF-κB p65 in atherosclerotic rabbits

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Asian Pacific Journal of Tropical Medicine 2013年第6期6卷 493-496页

作者： Ding-Zhu Shen san-Li Xin Chuan Chen Te Liu Shanghai Geriatric Institute of Chinese Medicine Longhua Hospital Affiliated Shanghai University of Traditional Chinese Medicine

Objective:To study the effect of atorvastatin on atherosclerotic ***:A total of 60 Now Zealand male rabbits were randomly divided into the normal group,model group and atorvastatin *** replication rabbit atherosclerotic model with immune injury combined with a high fat diet feeding was *** rabbits were sacrificed after 3 ***4 and NF-κB p65 were observed by HE staining,immunohistochemistry and western ***: The expression of TLR4,NF- k B p65 were significantly increased in the model group compared widi the normal *** expression of ti.R4 and NK- k B p65 decreased significantly in the atorvastatin group,and there was no difference compared with the normal ***: The effect of atorvastatin on adierosclerosis may be achieved by the inhibition of the expression of TLK4 and NF-κB p65.

关键词： Atherosclerosis Atorvastatin TLR4 NF-κB p65

Hook Benefit Evaluation on the Increase of Urban Construction Land and the Decrease of Rural Construction Land in the Suburbs of Chongqing City,China

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Asian Agricultural Research 2011年第3期3卷 86-88页

作者： WANG Ke,XIE De-ti,HUANG Chun-fang,WANG san College of Resource and Environment,Southwest University,Chongqing 400715,China

According to the socio-economic statistical data and the land use data of Jingguan Town in the year 2008,hook benefit evaluation index system suitable for the actual situation of research region is determined,based on the systematic analyses of the basic data of current status and the related information of hook in research *** Comprehensive Evaluation Method is adopted to evaluate the increase of construction land of Jingguan Town before and after the *** shows that the economic,social and ecological benefits of research region have significantly improved after the *** the fuzzy comprehensive evaluation index system and evaluation methods established in this research can provide references for the hook benefit evaluation in the suburbs of Chongqing City,China.

关键词： Construction land Benefit Hook Jingguan Town China

ti_(3)C_(2)T_(x)/SnO_(2)P–N heterostructure construction boosts room-temperature detecting formaldehyde

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Rare Metals 2024年第1期43卷 267-279页

作者： Yue Zhang Ming-Yue Wang Xiao-Guang san Yan-Bai Shen Guo-Sheng Wang Lei Zhang Dan Meng College of Chemical Engineering Shenyang University of Chemical TechnologyShenyang 110142China Institute for Superconducting and Electronic Materials(ISEM) Australian Institute for Innovative Materials(AIIM)University ofWollongongWollongongNSW2500Australia College of Resources and Civil Engineering Northeastern UniversityShenyang 110819China

Formaldehyde is a common atmospheric pollutant produced in industrial production and daily ***,the traditional semiconductor formaldehyde gas sensor cannot work at room temperature,which limits its practical ***,developing high-performance gas sensors for rapidly and accurately detecting formaldehyde at room temperature is an important *** this study,ti_(3)C_(2)Tx/SnO_(2)heterostructures were constructed,which could selectively detect formaldehyde at room temperature with a response value of 29.16%(10×10^(-6)).In addition,the sensor shows a remarkable theoretical detection limit of 5.09×10^(-9)and good longterm *** functional theory(DFT)simulations reveal that SnO_(2)nano spheres provide the majority of adsorption sites that strongly interact with ***,ti_(3)C_(2)T_(x)acting as a conductive layer facilitates the transfer of charge carriers so that they show a sensing response to formaldehyde at room ***,the formation of p-n heterostructures between SnO_(2)and ti_(3)C_(2)T_(x)boosts the Schottky barrier at the interface,which is the critical factor in enhancing the sensing properties by turning the Schottky barrier upon introducing formaldehyde *** perspective is expected to provide instructive guidance for utilizing MXene/metal oxide nanocomposites to improve the gas sensing performance at room temperature.

关键词： ti_(3)C_(2)T_(x)/SnO_(2)nanocomposites p-n heterostructures Formaldehyde sensing Room temperature DFT calculations

Effect of oxygen content and heat treatment on carbide precipitation behavior in PM Ni-base superalloys

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 827-835页

作者： Heng-san Liu Lin Zhang Xin-bo He Xuan-hui Qu Hong-min Zhu Guo-qing Zhang State Key Laboratory for Advanced Metals and Materials Beijing Key Laboratory for Powder Metallurgy and Particulate Materials University of Science and Tech-nology Beijing Beijing 100083 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China National Key Lab of High Temperature Structural Materials Beijing Institute of Aeronautical Materials Beijing 100095 China

The influence of oxygen content and heat treatment on the evolution of carbides in a powder metallurgy （PM） Ni-base superalloy was characterized. The results reveal that oxygen content has little influence on the precipitation of carbides inside the particles. However, under the consolidated state, stable ti oxides on the particle surface act as nuclei for the precipitation of prior particle boundaries （PPB）. Also, oxygen can diffuse internally along grain boundaries under compressive stress, which favors the precipitation of carbides inside the particles. Therefore, a higher amount of carbides will appear with more oxygen content in the case of consolidated alloys. It is also observed that PPB can be disrupted into discontinuous particles at 1200℃, but this carbide network is hard to be eliminated completely. The combined MC-M23C6 morphology approves the nucleation and growth mechanism of carbide evolution.

关键词： powder metallurgy nickel alloys superalloys oxygen heat treatment carbides precipitation