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Dual Space Analyzing Based on Symmetry Properties for Phonons of Si Quantum Dot

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Communications in Theoretical Physics 2002年第7期38卷 91-98页

作者： QIN Guo-yi REN shang-Fen ZHANG Zhi-Yong Department of Physics Nanjing University Nanjing 210093 China Department of Physics Illinois State University Normal IL 61790-4560 USA Department of Physics Tianjin Normal University Tianjin 300074 China

Phonon modes in spherical Si quantum dots (QDs) with up to 7.9 nm in diameter are calculated by using the projection operators of the group theory into valence force field model. The phonons of dot modes in each of five irreducible representations (symmetries) are classified by using a dual space analysis method. It is found that the bulk-like modes with localization radius much smaller than the dot's radius have clearly pronounced bulk specific-κdefinite bulk band (one in six modes). In Si dots of all sizes, each specific bulk-like dot mode has specific *** dot modes and bulk-like X-derived TA and LA dot modes red-shift in frequency with decreasing dot size. There is almost not LO/TO mixing for bulk-like modes. As for the surface-like modes localized at the periphery of the dot,their eigenmodes have not a dominant bulk specific-κ point parentage or a dominant BZ parentage around some special point. They are a superposition of many bulk bands with κ from all over the bulk BZ. They have much significant mode mixing than the bulk-like phonons. The classification of dot modes based on the symmetry of group theory will bring advantageous to the discussion of Ramam spectrum, electron-phonon interaction and other phonon-assisted effects in QDs.

关键词： phonon modes, quantum dots, dual space analyzing

Inverted V-shaped evolution of superconducting temperature in SrBC under pressure

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Chinese Physics B 2021年第7期30卷 413-419页

作者： ru-yi Zhao Xun-Wang Yan Miao Gao Department of Physics School of Physical Science and TechnologyNingbo UniversityNingbo 315211China College of Physics and Engineering Qufu Normal UniversityQufu 273165China

Based on density functional first-principles calculations and anisotropic Eliashberg equations,we have investigated the electronic structure,lattice dynamics,and phonon-mediated superconductivity in newly synthesized layered compound Sr BC under *** from Li BC and Mg B2,our calculations surprisingly reveal that Sr BC is isotropic in compressibility,due to the accumulation of substantial electrons in the interstitial *** find that the Sr phonons strongly couple with B-2 pz orbital and the interstitial states,giving rise to a two-gap superconductivity in Sr BC,whose transition temperature shows an inverted V-shaped dependence on *** maximal transition temperature is about 22 K at50 *** both sides of 50 GPa,the transition temperature exhibits quasi-linear variation with positive and negative slopes,*** a variation of transition temperature is infrequent among phonon-mediated *** competition between enhanced electron–phonon matrix element and hardened phonons plays an essential role in governing the behavior of the critical temperature.

关键词： SrBC phonon-mediated superconductivity anisotropic Eliashberg theory first-principles calculation maximally localized Wannier functions

SegNet-based first-break picking via seismic waveform classification directly from shot gathers with sparsely distributed traces

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Petroleum Science 2022年第1期19卷 162-179页

作者： San-yi Yuan Yue Zhao Tao Xie Jie Qi shang-Xu Wang State Key Laboratory of Petroleum Resources and Prospecting CNPC Key Laboratory of Geophysical ExplorationChina University of PetroleumBeijing 102249China China Oilfield Services Ltd. TangguTianjin 300452China University of Oklahoma ConocoPhillips School of Geology and GeophysicsNormanOKUSA

Manually picking regularly and densely distributed first breaks(FBs)are critical for shallow velocitymodel building in seismic data ***,it is time *** employ the fullyconvolutional Seg Net to address this issue and present a fast automatic seismic waveform classification method to pick densely-sampled FBs directly from common-shot gathers with sparsely distributed *** feeding a large number of representative shot gathers with missing traces and the corresponding binary labels segmented by manually interpreted fully-sampled FBs,we can obtain a welltrained Seg Net *** any unseen gather including the one with irregular trace spacing is inputted,the Seg Net can output the probability distribution of different categories for waveform *** FBs can be picked by locating the boundaries between one class on post-FBs data and the other on pre-FBs *** land datasets with each over 2000 shots are adopted to illustrate that one well-trained 25-layer Seg Net can favorably classify waveform and further pick fully-sampled FBs verified by the manually-derived ones,even when the proportion of randomly missing traces reaches50%,21 traces are missing consecutively,or traces are missing regularly.

关键词： First-break picking Deep learning Irregular seismic data Waveform classification

CD13 inhibition augments DR4-induced tumor cell death in a p-ERK1/2-independent manner

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Cancer Biology & Medicine 2021年第2期18卷 569-586页

作者： Jun Ni Xiaofei Wang Yue shang yi Li Shuzhen Chen Department of Cancer Research Institute of Medicinal BiotechnologyChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Objective:Death receptor 4(DR4;TRAIL-R1)critically mediates extrinsic apoptosis cascades via binding to TNF-related apoptosis-inducing ligand(TRAIL).However,intrinsic and/or acquired resistance are observed in the clinical application of *** aim of this study was to investigate the function and molecular mechanism of CD13 in the TRAIL/DR4 pathway against tumor cells,and provide a new strategy for improving therapeutic efficacy or overcoming ***:TRAIL protein was expressed as a secretory protein in a Pichia pastoris expression system and was isolated and purified by affinity *** cell viability and apoptosis were evaluated with MTT(thiazolyl blue tetrazolium bromide)assays and annexin V-FITC/PI staining with flow cytometry analysis,*** blot analysis was used to detect the levels of the indicated proteins in tumor ***4 degradation or stability was examined with cycloheximide chase assays,and cell surface DR4 was assessed with flow cytometric analysis after staining with a FITC-conjugated *** effects of cell migration were determined with Transwell and gelatin zymography assays.A xenograft nude mouse model was used to detect the anti-tumor effect in vivo,and the proliferation in tumor tissues was examined with immunohistochemical ***:CD13 inhibition potently sensitized tumor cells to TRAIL-induced killing,including proliferation inhibition,increased apoptosis,and migration *** addition,the inhibition of CD13 elevated both total cellular expression and cell surface DR4 through stabilizing DR4 by suppressing its ***4 si RNA attenuated the enhanced anti-tumor effects of TRAIL plus CD13 ***,these phenomena were p-ERK1/2 independent,although p-ERK1/2 down-regulation was tightly correlated with the cooperation of TRAIL and CD13 ***,a synergistic decrease in tumor growth was surprisingly achieved in the xenograft model by treatment of

关键词： CD13 inhibition DR4 TRAIL neoplasm therapeutic targets

Optimized photocatalytic regeneration of adsorption-photocatalysis bifunctional composite saturated with Methyl Orange

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Journal of Environmental Sciences 2020年第8期32卷 40-51页

作者： yi shang Xing Li Yanling Yang Nan Wang Xiaoxuan Zhuang Zhiwei Zhou College of Architecture and Civil engineering Beijing University of TechnologyBeijing 100124China

Photo-responsive adsorption-photocatalysis nanocomposites are generally used in water and wastewater decontamination;however,the prolonged adsorption capacity of composites and the role of adsorption in concomitant photocatalysis are typically *** composites can be regenerated under light irradiation as their adsorption capacity ***,a novel adsorption-photocatalysis bifunctional nanocomposite,Bi-doped TiO2 supported on powdered activated carbon(Bi2O3/TiO2/PAC),was prepared using the solimpregnation-hydrothermal ***2O3/TiO2/PAC with a secondary calcination temperature of 700℃under a nitrogen atmosphere was selected for maximum adsorption capacity on Methyl Orange(MO).The composite displayed an excellent adsorption capacity and was easily separated and *** results demonstrate that 71.2%photocatalytic regeneration efficiency could be attained under visible light irradiation for 1 hr at an intensity of 750 W/m^2 and pH *** of the as-prepared Bi2O3/TiO2/PAC nanocomposite(700℃)indicates that it possesses a highly specific surface area and great optical properties,showing bifunctional adsorption-photocatalysis *** p-n heterojunction of the composite played a dominant role in the photocatalytic regeneration process,and effective degradation of MO could be achieved along with composite regeneration.

关键词： Photocatalytic regeneration Nanocomposite Powdered activated carbon Adsorption Photocatalysis

Determination of rock mass integrity coefficient using a non-invasive geophysical approach

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1426-1440页

作者： Muhammad Hasan Yanjun shang Xuetao yi Peng Shao Meng He Key Laboratory of Shale Gas and Geoengineering(KLSGG) Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100029China

Determination of rock mechanical parameters is the most important step in rock mass quality evaluation and has significant impacts on geotechnical engineering *** mass integrity coefficient(KV)is one of the most efficient parameters,which is conventionally determined from *** approaches,however,are time-consuming and expensive,offer low data coverage of point measurements,require heavy equipment,and are hardly conducted in steep topographic ***,borehole approaches cannot assess the subsurface thoroughly for rock mass quality ***,use of geophysical methods is non-invasive,rapid and *** proposed geophysical approach makes useful empirical correlation between geophysical and geotechnical *** evaluated the rock mass quality via integration between KV measured from the limited boreholes and inverted resistivity obtained from electrical resistivity tomography(ERT).The borehole-ERT correlation provided KV along various geophysical profiles for more detailed 2D/3D(two-/three-dimensional)mapping of rock mass *** subsurface was thoroughly evaluated for rock masses with different engineering qualities,including highly weathered rock,semi-weathered rock,and fresh ***,ERT was integrated with induced polarization(IP)to resolve the uncertainty caused by water/clay *** results show that the proposed method,compared with the conventional approaches,can reduce the ambiguities caused by inadequate data,and give more accurate insights into the subsurface for rock mass quality evaluation.

关键词： Geotechnical engineering Rock mass integrity coefficient Rock mechanical parameters Geophysical parameters Electrical resistivity tomography(ERT) Induced polarization(IP)

Role of temperature in tribolayers in fretting wear ofγ-TiAl alloy

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Friction 2024年第5期12卷 939-953页

作者： Yulei YANG Hongfei shang Huiping PEI Jimin XU yi LIANG Minghui PAN School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China Institute of Tribology Hefei University of TechnologyHefei230009China

The formation of tribolayers may play significant influences on fretting *** elevated temperature,the adhesion among wear debris and the increased diffusion rate facilitate the formation of ***,the intensification of oxidation at elevated temperature and the low diffusion rate in oxides may play an adverse *** present study aims to investigate the role of temperature in tribolayers in fretting wear using aγ-TiAl *** electron microscope,energy dispersive spectrometer,Raman spectrometer,transmission electron microscope and nanoindentation were utilized to investigate the wear debris,tribolayers,and wear *** fretting tests showed that,compared with that at room temperature(RT)and 350℃,significant reduction in wear rate and decrease in the fluctuation of friction coefficient occurred at 550 and 750℃.It was further revealed that when temperature raised from room temperature(RT)to 750℃,the oxidation of the wear debris increased slightly and the diffusion coefficients increased prominently,which facilities the formation of well tribo-sintered *** well tribo-sintered tribolayers presented homogenous structure,nanocrystalline grains with excellent mechanical properties,and resulted in the improvement in the fretting wear resistance of theγ-TiAl alloy at 550 and 750℃.

关键词： tribolayer temperature fretting wear γ-TiAl alloy

Incidence of surgical site infection in minimally invasive colorectal surgery

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1121-1129页

作者： Lu-Ting Ni ru Zhao yi-ru Ye yi-Ming Ouyang Xin Chen Department of Surgery The First Affiliated Hospital of Soochow UniversitySuzhou 215000Jiangsu ProvinceChina

BACKGROUND Surgical site infection(SSI)is a common complication of colorectal *** invasive surgery notably reduces the incidence of *** study aimed to compare the incidences of SSI after robot-assisted colorectal surgery(RACS)vs that after laparoscopic assisted colorectal surgery(LACS)and to analyze associated risk factors for SSI in minimally invasive colorectal *** To compare the incidences of SSI after RACS and LACS,and to analyze the risk factors associated with SSI after minimally invasive colorectal *** Clinical data derived from patients who underwent minimally invasive colorectal surgery between October 2020 and October 2022 at the First Affiliated Hospital of Soochow University were *** in clinical characteristics and surgeryrelated information associated with RACS and LACS were compared,and possible risk factors for SSI were *** A total of 246 patients(112 LACS and 134 RACS)were included in the ***(17.5%)developed *** proportions of patients who developed SSI were similar in the two groups(17.9%vs 17.2%,P=0.887).Diabetes mellitus,intraoperative blood loss≥100 mL,and incision length were independent risk factors for *** additional risk factors included neoadjuvant therapy,lesion site,and operation *** There was no difference in SSI incidence in the RACS and LACS *** mellitus,intraoperative blood loss≥100 mL,and incision length were independent risk factors for postoperative SSI.

关键词： Colorectal surgery Minimally invasive surgery Surgical site infection

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun Jing-yi Shi yi-Fei Liu shang-Ming Chen Liu-Liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path