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Injection molding of ultra-fine Si_3N_4 powder for gas-pressure sintering

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International Journal of Minerals,Metallurgy and Materials 2015年第6期22卷 654-659页

作者： xian-feng Yang Jiang-hong Yang Xie-wen xu Qi-cheng Liu Zhi-peng Xie Wei Liu College of Physics and Electronics Science Changsha University of Science and Technology School of Materials Science and Engineering Tsinghua University

The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm^3, 16.5 GPa, and 7.2 MPa·m^1/2, respectively.

关键词： ceramic materials silicon nitride injection molding sintering near net shaping

Differences and identification on multi-time hydrocarbon generation of carboniferous-permian coaly source rocks in the Huanghua Depression,Bohai Bay Basin

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Petroleum Science 2024年第2期21卷 765-776页

作者： Jin-Jun xu xian-Gang cheng Shu-Nan Peng Jun-Cai Jiang Qi-Long Wu Da Lou Fu-Qi cheng La-Mei Lin National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShandongChina PetroChina Dagang Oilfield Company Tianjin300280China

Coal is a solid combustible mineral,and coal-bearing strata have important hydrocarbon generation potential and contribute to more than 12%of the global hydrocarbon ***,the deposition and hydrocarbon evolution process of ancient coal-bearing strata is characterized by multiple geological times,leading to obvious distinctions in their hydrocarbon generation potential,geological processes,and production,which affect the evaluation and exploration of hydrocarbon resources derived from coaly source rocks *** study aimed to identify the differences on oil-generated parent macerals and the production of oil generated from different coaly source rocks and through different oil generation *** with the analysis of previous tectonic burial history and hydrocarbon generation history,high-temperature and high-pressure thermal simulation experiments,organic geochemistry,and organic petrology were performed on the Carboniferous-Permian(C-P)coaly source rocks in the Huanghua Depression,Bohai Bay *** oil-generated parent macerals of coal's secondary oil generation process(SOGP)were mainly hydrogen-rich collotelinite,collodetrinite,sporinite,and cutinite,while the oil-generated parent macerals of tertiary oil generation process(TOGP)were the remaining small amount of hydrogen-rich collotelinite,sporinite,and cutinite,as well as dispersed soluble organic matter and unexhausted residual *** with coal,the oil-generated parent macerals of coaly shale SOGP were mostly sporinite and *** part of hydrogen-poor vitrinite,lacking hydrocarbon-rich macerals,and macerals of the TOGP,in addition to some remaining cutinite and a small amount of crude oil and bitumen from SOGP contributed to the oil *** results indicated that the changes in oil yield had a good junction between SOGP and TOGP,both coal and coaly shale had higher SOGP aborted oil yield than TOGP starting yield,and coaly shale TOGP peak oil yield was low

关键词： Thermal simulation Multi-time oil generation processes Coaly source rock Carboniferous-permian Huanghua Depression

Short-Time Decoherence of Solid-State Qubit at Optimal Operation Points

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Communications in Theoretical Physics 2005年第5X期44卷 827-832页

作者： ZHAO xu LIANG xian-Ting Department of Physics and Institute of Modern Physics Ningbo University Ningbo 315211 China

We investigate the short-time decoherence of a solid-state qubit under Ohmic noise at optimal operation points. The decoherence is analyzed by maximum norm of the deviation density operator. It is shown that at the temperature T = 3 mK, the loss of the fidelity due to decoherence is much smaller than the DiVincenzo low decoherence criterion, which means that the mode/may be an optimal candidate of qubit for quantum computation.

关键词： short-time decoherence Josephson junction qubit ohmic noise

Improved mass relations of mirror nuclei

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Nuclear Science and Techniques 2024年第9期35卷 178-185页

作者： cheng xu Man Bao Department of Physics University of Shanghai for Science and TechnologyShanghai 200093China

In this study,we revisit the previous mass relations of mirror nuclei by considering 1/N-and 1/Z-dependent terms and the shell effect across a *** root-mean-squared deviation is 66 keV for 116 nuclei with neutron number N≥10,as com-pared with experimental data compiled in the AME2020 *** predicted mass excesses of 173 proton-rich nuclei,including 98 unknown nuclei,are tabulated in the Supplemental Material herein with competitive accuracy.

关键词： Nuclear mass Mirror nuclei Proton-rich nuclei

Persistence and Extinction in Two Species Models with Impulse

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Acta Mathematica Sinica,English Series 2006年第2期22卷 447-454页

作者： xian Zhang WEN Zhi cheng WANG Department of Mathematics Hunan Normal University Department of Applied Mathematics Hunan University

Both uniform persistence and global extinction are established for a two species predatorprey and competition system with impulse by appealing to theories of abstract persistence, asymptotically autonomous semiflows, ... 详细信息

关键词： Impulse Persistence Extinction

First-principles-aided thermodynamic modeling of transition-metal heterogeneous catalysts:A review

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Green Energy & Environment 2020年第3期5卷 286-302页

作者： Haoxiang xu Daojian cheng State Key Laboratory of Organic-Inorganic Composites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing100029China

Over the past decade,the first-principles-aided thermodynamic models have become standard theoretical tools in research on structural stability and evolution of transition-metal heterogeneous catalysts under reaction *** in first-principles-aided thermodynamic models mean it is now possible to enable the operando computational modeling,which provides a deep insight into mechanism behind structural stability and evolution,and paves the way for high-through screening for promising transition-metal heterogeneous ***,we briefly review the framework and foundation of first-principles-aided thermodynamic models and highlight its contribution to stability analysis on catalysts and identification of reaction-induced structural evolution of catalyst under reaction *** present review is helpful for understanding the ongoing developments of first-principles-aided thermodynamic models,which can be employed to screen high-stability catalysts and predict their structural reconstruction in future rational catalyst design.

关键词： First-principles calculation Thermodynamic principle Transition metal catalyst Structural stability Structural evolution

Inhibition Performance of Enhanced-Mo Inhibitor for Carbon Steel in 55% LiBr Solution

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Journal of Iron and Steel Research International 2008年第1期15卷 49-54页

作者： LIANG cheng-hao HU xian-qi Electromechanics and Materials Engineering College Dalian Maritime University Dalian 116026 Liaoning China School of Chemical Engineering Dalian University of Technology Dalian 116012 Liaoning China

The inhibition performance of enhanced-Mo inhibitor for carbon steel in 55% LiBr solution was measured by means of chemical immersion,electrochemical measurements,and physical detection *** indicated that enhanced-Mo inhibitor showed excellent inhibition performance of carbon steel in 55% LiBr solution,especially at high *** increasing the temperature of solution from 160 ℃ to 240 ℃,the corrosion rates of carbon steel increased from 17.67 μm/a to 33.07 μm/***-Mo inhibitor might improve the anodic polarization performance of carbon steel and widen the passive potential region of carbon steel in 55% LiBr ***-Mo inhibitor belongs to anodic *** 55% LiBr solution,the relationship between corrosion current density icorr and corrosion potential Ecorr of carbon steel accorded with the equation lgicorr=-2.66-3.54Ecorr,and the value of cathodic Tafel constant βc for the H2 reaction was 282 *** 55% LiBr solution contained enhanced-Mo inhibitor,a passive film comprising Fe3O4 and MoO2 was formed on the carbon steel surface by electrochemical *** corrosion of carbon steel might be retarded by this protective film,and the anticorrosion performance of carbon steel in 55% LiBr solution might be improved by enhanced-Mo inhibitor.

关键词： corrosion enhanced-Mo inhibitor carbon steel

Vascular reconstruction provides short-term and long-term survival benefits for patients with hilar cholangiocarcinoma:A retrospective,multicenter study

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Hepatobiliary & Pancreatic Diseases International 2024年第6期23卷 595-603页

作者： Yi-xian Huang Chao xu cheng-cheng Zhang Guang-Yi Liu Xing-Chao Liu Hai-Ning Fan Bi Pan Yuan-cheng Li Department of Hepatobiliary Surgery Southwest HospitalThird Military Medical University(Army Medical University)Chongqing 400038China Department of Hepatobiliary Surgery Liaocheng People’s HospitalLiaocheng 252000China Sichuan Academy of Medical Sciences&Sichuan Provincial People’s Hospital Chengdu 610000China Qinghai University Affiliated Hospital Xining 810016China

Background:In patients with hilar cholangiocarcinoma(HCCA),radical resection can be achieved by resection and reconstruction of the ***,whether vascular reconstruction(VR)improves long-term and short-term prognosis has not been demonstrated ***:This was a retrospective multicenter study of patients who received surgery for HCCA with or without *** associated with overall survival(OS)and recurrence-free survival(RFS)were identified based on Cox ***-Meier curves were used to explore the impact of *** mean survival time(RMST)was used for comparisons of short-term survival between the ***’intraoperative and postoperative characteristics were ***:Totally 447 patients were *** divided these patients into 3 groups:VR with radical resections(n=84);non-VR radical resections(n=309)and non-radical resection(we pooled VRnonradical and non-VR nonradical together,n=54).Cox regression revealed that carbohydrate antigen 242(CA242),vascular invasion,lymph node metastasis and poor differentiation were independent risk factors for OS and *** was no significant difference of RMST between the VR and non-VR radical groups within 12 months after surgery(10.18 vs.10.76 mon,P=0.179),although the 5-year OS(P<0.001)and RFS(P<0.001)were worse in the VR radical *** incidences of most complications were not significantly different,but those of bile leakage(P<0.001)and postoperative infection(P=0.009)were higher in the VR radical group than in the non-VR radical ***,the levels of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)up to 7 days after surgery tended to decrease in all *** was no significant difference in the incidence of postoperative liver failure between the VR and non-VR radical ***:Radical resection can be achieved with VR to improve the survival rate without worsening short-term survival compared with resection wit

关键词： Hilar cholangiocarcinoma Hepatectomy Vascular reconstruction Prognosis

Intricate evolutions of multiple-period post-buckling patterns in bilayers

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Science China(Physics,Mechanics & Astronomy) 2021年第1期64卷 72-81页

作者： Zhe cheng Fan xu Institute of Mechanics and Computational Engineering Department of Aeronautics and AstronauticsFudan UniversityShanghai200433China

Surface instability of compliant film/substrate bilayers has raised considerable interests due to its broad applications such as wrinkle-driven surface renewal and antifouling,shape-morphing for camouflaging skins,and micro/nano-scale surface patterning ***,it is still a challenge to precisely predict and continuously trace secondary bifurcation transitions in the nonlinear post-buckling ***,we develop lattice models to precisely capture the nonlinear morphology evolution with multiple mode transitions that occur in the film/substrate *** on our models,we reveal an intricate post-buckling phenomenon involving successive flat-wrinkle-doubling-quadrupling-fold ***-stretch and pre-compression of the substrate,as well as bilayer modulus ratio,can alter surface morphology of film/substrate *** high substrate pre-tension,hierarchical wrinkles emerge in the bilayer with a low modulus ratio,while a wrinkle-to-ridge transition occurs with a high modulus ***,with moderate substrate pre-compression,the bilayer eventually evolves into a period-tripling *** diagrams based on neo-Hookean and Arruda-Boyce constitutions are drawn to characterize the influences of different factors and to provide an overall view of ultimate pattern *** understanding and quantitative prediction of the nonlinear morphological transitions of soft bilayer materials hold potential for multifunctional surface regulation.

关键词： hierarchical wrinkle period-doubling period-tripling period-quadrupling fold ridge