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Journal of Wuhan University of Technology(Materials Science) 2023年第4期38卷 759-765页

作者：赵东升 jing qiang SUN Jianwei 张金咏 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

The Si_(3)N_(4)/SiC gradient material with a gradient composition structure was prepared by a hot pressing *** sinterability,distribution of residual stress and the effect of residual stress on mechanical properties of Si_(3)N_(4)/SiC gradient materials were *** research results show that,at 1750℃,Si_(3)N_(4)/SiC gradient materials with different ratios can achieve co-sintering,and the overall relative density of the sample reaches 98.5%.Interestingly,the flexural strength of Si_(3)N_(4)/SiC gradient material is related to its loading *** flexural strength of SiC as the loading surface is about 35%higher than that of Si_(3)N_(4)as the loading *** analysis of the residual stress of the material in the gradient structure shows that the gradient stress distribution between the two phases is a vital factor affecting the mechanical properties of the *** the increase of SiC content in the gradient direction,the fracture toughness of each layer of Si_(3)N_(4)/SiC gradient materials gradually *** surface hardness of the pure SiC side is lower than that reported in other literature.

关键词： Si_(3)N_(4) SiC gradient material residual stress mechanical properties

Optimization of Well Position and Sampling Frequency for Groundwater Monitoring and Inverse Identification of Contamination Source Conditions Using Bayes’Theorem

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Computer Modeling in Engineering & Sciences 2019年第5期119卷 373-394页

作者： Shuangsheng Zhang Hanhu Liu jing qiang Hongze Gao Diego Galar jing Lin School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou221116China School of Mathematics China University of Mining and TechnologyXuzhou221116China GHD Services Inc455 Philip StreetWaterlooOntarioCanada Division of Operation and Maintenance Engineering Department of CivilEnvironmental and Natural Resources EngineeringLulea University of Technology97187 LuleaSweden Xuzhou Urban Water Resources Management Office Xuzhou221018China.

Coupling Bayes’Theorem with a two-dimensional(2D)groundwater solute advection-diffusion transport equation allows an inverse model to be established to identify a set of contamination source parameters including source intensity(M),release location(0 X,0 Y)and release time(0 T),based on monitoring well *** address the issues of insufficient monitoring wells or weak correlation between monitoring data and model parameters,a monitoring well design optimization approach was developed based on the Bayesian formula and information *** demonstrate how the model works,an exemplar problem with an instantaneous release of a contaminant in a confined groundwater aquifer was *** information entropy of the model parameters posterior distribution was used as a criterion to evaluate the monitoring data quantity *** optimal monitoring well position and monitoring frequency were solved by the two-step Monte Carlo method and differential evolution algorithm given a known well monitoring locations and monitoring *** on the optimized monitoring well position and sampling frequency,the contamination source was identified by an improved Metropolis algorithm using the Latin hypercube sampling *** case study results show that the following parameters were obtained:1)the optimal monitoring well position(D)is at(445,200);and 2)the optimal monitoring frequency(Δt)is 7,providing that the monitoring events is set as 5 *** the optimized monitoring well position and frequency,the mean errors of inverse modeling results in source parameters(M,X0,Y0,T0)were 9.20%,0.25%,0.0061%,and 0.33%,*** optimized monitoring well position and sampling frequency canIt was also learnt that the improved Metropolis-Hastings algorithm(a Markov chain Monte Carlo method)can make the inverse modeling result independent of the initial sampling points and achieves an overall optimization,which significantly improved the accuracy and numerical stability

关键词： Contamination source identification monitoring well optimization Bayes’Theorem information entropy differential evolution algorithm Metropolis Hastings algorithm Latin hypercube sampling

Thermodynamic analysis and preparation of β-SiC/ZrO_2 composites

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International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 581-585页

作者： Bei-yue Ma jing-kun Yu qiang Zhu Yong Sun School of Materials and Metallurgy Northeastern University Shenyang 110004 China

A predominance area diagram for the Zr-Si-C-O system at 1773 K was plotted according to correlative thermodynamic data. β-SiC/ZrO2 composites were prepared based on the phase diagram by carbothermal reduction of zircon （ZrSiO4） in argon atmosphere. Zircon and carbon black were mixed according to the C/ZrSiO4 mass ratio of 0.2, and with 0, 1wt% and 2wt% extra addition of La2O3. Phase evolution of the mixture was investigated at 1723-1803 K by X-ray powder diffraction, and the microstructure of the product prepared at 1803 K for 4 h was examined by scanning electronic microscope. The results show that the decomposition of ZrSiO4 and the formation of β-SIC can be promoted by increasing the heating temperature and adding La2O3. The β-SiC/ZrO2 composites can be prepared at 1803 K for 4 h in a mixture of zircon, carbon black and La2O3, and the contents of β-SIC and m-ZrO2 in the product sample with 2wt% La2O3 reach the highest values of 10.8wt% and 89.2wt%, respectively. The crystal size of the products is about 200 nm.

关键词： composites silicon carbide zirconium dioxide carbothermal reduction thermodynamic analysis

Relationship between microstructure and corrosion behavior of high-grade pipeline steel in a low-temperature environment

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Journal of Iron and Steel Research International 2021年第8期28卷 1037-1046页

作者： Jia-qiang jing Jie Guo Ba Li Shu-jun Jia Yi Ren School of Oil and Gas Engineering Southwest Petroleum UniversityChengdu 610500SichuanChina Department of Structural Steels Central Iron and Steel Research InstituteBeijing 100081China State Key Laboratory of Metal Material for Marine Equipment and Application of Iron and Steel Research Institutes of Ansteel Group Corporation Anshan 114009LiaoningChina

The relationship between micro structure and corrosion behavior of high-grade pipeline steel under low-temperature conditions was comparatively investigated by the potentiodynamic polarization and electrochemical impedance spec-troscopy test combining with optical micrographs,scanning electron microscopy,transmission electron microscopy and electron back-scattered *** results showed that,compared with room and high temperature,low temperature could influence the corrosion behavior of high-grade pipeline steel,which means that the corrosion potential and current density decreased and the corrosion resistance increased ***,double layer structures of the interface became thicker and more *** low-temperature environment,acicular ferrite had the martensite/austenite constituents with less amount and smaller size,a higher density of low angle grain boundaries and smaller effective grain sizes compared with granular bainite,which demonstrated higher corrosion resistance.

关键词： Low temperature High-grade pipeline steel Corrosion behavior Resistance Acicular ferrite Granular bainite Martensite/austenite constituent

Continuous steel box girders and reinforced concrete structures in the Main Bridge Project of Hong Kong-Zhuhai-Macao Bridge

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2020年第4期21卷 249-254页

作者： qiang jing Hong Kong-Zhuhai-Macao Bridge Authority Zhuhai 519060China

As the longest sea-crossing highway bridge in the world,the 55-km Hong Kong-Zhuhai-Macao Bridge(HZMB)directly connects Hong Kong,Zhuhai,and Macao,which are three cities in China that are geographically close but separated by the Pearl River Estuary(PRE).The construction of the project lasted from January 2011 to February 2018 and was finally opened to traffic in October 2018(Gao et al.,2016;Zhu et al.,2019).The total investment of the project was 126.9 billion CNY(about 18.03 billion USD).As shown in Fig.1,the HZMB consists of three main sections:the Main Bridge(29.6 km)in the middle,the Hong Kong Link Road(12 km)in the east,and the Zhuhai Link Road(13.4 km)in the *** the longest part,the estimated cost of the Main Bridge was 38.1 billion CNY(about 5.41 billion USD).The actual cost,however,was 51.1 billion CNY(about 7.26 billion USD).

关键词：港珠澳大桥连续钢箱梁施工控制钢筋混凝土结构钢筋锈蚀

Transjugular intrahepatic portosystemic shunt versus open splenectomy and esophagogastric devascularization for portal hypertension with recurrent variceal bleeding

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Hepatobiliary & Pancreatic Diseases International 2017年第2期16卷 169-175页

作者： An-Ping Su Zhao-Da Zhang Bo-Le Tian jing-qiang Zhu Department of Thyroid Surgery West China Hospital Sichuan University Chengdu 610041 China Department of Hepatobiliopancreatic Surgery West China Hospital Sichuan University Chengdu 610041 China

BACKGROUND： Transjugular intrahepatic portosystemic shunt（TIPS） and open splenectomy and esophagogastric devascularization（OSED） are widely used to treat patients with portal hypertension and recurrent variceal bleeding（PHRVB）. This study aimed to compare the effectiveness between TIPS and OSED for the treatment of ***： The data were retrospectively retrieved from 479 cirrhotic patients（Child-Pugh A or B class） with PHRVB, who had undergone TIPS（TIPS group） or OSED（OSED group） between January 1, 2010 and October 31, ***： A total of 196 patients received TIPS, whereas 283 underwent OSED. Within one month after TIPS and OSED, the rebleeding rates were 6.1% and 3.2%, respectively（P=0.122）. Significantly lower incidence of pleural effusion,splenic vein thrombosis, and pulmonary infection, as well as higher hepatic encephalopathy rate, shorter postoperative length of hospital stay, and higher hospital costs were observed in the TIPS group than those in the OSED group. During the follow-up periods（29 months）, significantly higher incidences of rebleeding（15.3% vs 4.6%, P=0.001） and hepatic encephalopathy（17.3% vs 3.9%, P=0.001） were observed in the TIPS group than in the OSED group. The incidence of instent stenosis was 18.9%. The survival rates were 91.3% in the TIPS group and 95.1% in the OSED group. The long-term liver function did not worsen after either TIPS or ***： For the patients with liver function in the Child-Pugh A or B class, TIPS is not superior over OSED in terms of PHRVB treatment and rebleeding prevention.

关键词： liver cirrhosis portal hypertension recurrent variceal bleeding transjugular intrahepatic portosystemic shunt open splenectomy and esophagogastric devascularization

A Rapid Crack Detection Technique Based on Attention for Intelligent M&O of Cross-Sea Bridge

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China Ocean Engineering 2024年第5期38卷 866-876页

作者： ZHOU Yong-chuan LI Guang-jun WEI Wei WANG Ya-meng jing qiang Hong Kong-Zhuhai-Macao Bridge Authority Zhuhai 519015China National Observation and Research Station of Material Corrosion and Structural Safety of Hong Kong-Zhuhai-Macao Bridge in Guangdong Zhuhai 519000China Wuhan Maritime Communication Research Institute Wuhan 430079China

Rapid and accurate segmentation of structural cracks is essential for ensuring the quality and safety of engineering *** practice,however,this task faces the challenge of finding a balance between detection accuracy and *** alleviate this problem,a lightweight and efficient real-time crack segmentation framework was ***,in the network model system based on an encoding-decoding structure,the encoding network is equipped with packet convolution and attention mechanisms to capture features of different visual scales in layers,and in the decoding process,we also introduce a fusion module based on spatial attention to effectively aggregate these hierarchical *** are connected by pyramid pooling model(PPM)*** results show that the crack segmentation accuracy and real-time operation capability larger than 76%and 15 fps,respectively,are validated by three publicly available *** wide-ranging results highlight the potential of the model for the intelligent O&M for cross-sea bridge.

关键词： bridge defect detection crack detection lightweight design

Contributions to Hom-Schunck optical flow equations-part I： Stability and rate of convergence of classical algorithm

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Journal of Central South University 2013年第7期20卷 1909-1918页

作者： DONG Guo-hua AN Xiang-jing FANG Yu-qiang HU De-wen College of Mechatronics and Automation National University of Defense Technology Changsha 410073 China

Globally exponential stability （which implies convergence and uniqueness） of their classical iterative algorithm is established using methods of heat equations and energy integral after embedding the discrete iteration into a continuous flow. The stability condition depends explicitly on smoothness of the image sequence, size of image domain, value of the regularization parameter, and finally discretization step. Specifically, as the discretization step approaches to zero, stability holds unconditionally. The analysis also clarifies relations among the iterative algorithm, the original variation formulation and the PDE system. The proper regularity of solution and natural images is briefly surveyed and discussed. Experimental results validate the theoretical claims both on convergence and exponential stability.

关键词： optical flow Hom-Schunck equations globally exponential stability convergence convergence rate heat equations energy integral and estimate Gronwall inequality natural images regularity

Paired-Pd(Ⅱ) centers embedded in HKUST-1 framework: Tuning the selectivity from dimethyl carbonate to dimethyl oxalate

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Journal of Energy Chemistry 2022年第4期31卷 233-240页

作者： Hong-Zi Tan Zhe-Ning Chen Kai-qiang jing jing Sun Yu-Ping Xu Ning-Ning Zhang Zhong-Ning Xu Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Chemistry&Chemical Engineering Shandong University of TechnologyZibo 255049ShandongChina School of Chemistry and Chemical Engineering Liaocheng UniversityLiaocheng 252000ShandongChina

CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.

关键词： CO Methyl nitrite Oxidative coupling Dimethyl oxalate Paired-Pd(Ⅱ)centers HKUST-1

An enantioselective formal synthesis of (-)-thujopsene

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Chinese Chemical Letters 2008年第3期19卷 256-258页

作者： Chen Xi Zhang Li jing Fang Fu qiang Bi Yu Lin Li State Key Laboratory of Applied Organic Chemistry and Institute of Organic Chemistry Lanzhou University Lanzhou 730000 China

Dihydromayurone （3）, a key intermediate to synthesize （-）-thujopsene （1）, was efficient enantiocontrolled synthesized from （＋）-dihydrocarvone through 9 steps in an overall yield of 19.3%. The key step was the... 详细信息

关键词： Thujopsene Dihydromayurone Synthesis Dihydrocarvone Simmons-Smith reaction