检索结果-南通市图书馆

Current research into the use of supercritical CO2 technology in shale gas exploitation

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2019年第5期29卷 739-744页

作者： Wang meng Huang Kai xie Weidong Dai Xuguang School of Resources and Earth Science China University of Mining&TechnologyXuzhou 221116China Key Laboratory of Coalbed Methane Resource&Reservoir Formation Process Ministry of EducationChina University of Mining&TechnologyXuzhou 221008China College of Geology and Mining Engineering Xinjiang UniversityUrumqi 830046China

The use of supercritical CO2 for shale gas extraction is a promising new *** paper explores current research into this process,looking at analysis of the mechanism of CH4 displacement in nanoporous shale,the positive and negative effects accompanying its use for sequestration as well as organic extraction,the migration of elements and the swelling process,and the macro and micro control mechanisms involved in permeability enhancement in *** directions for future research are also considered through comparison with hydraulic *** research findings indicate that ScCO2 fluid replacement can be used to increase gas production and seal up greenhouse gases as an effective,clean and safe method of shale gas *** is particularly effective for promoting the desorption of CH4 in shale reservoirs that have developed fine neck-wide body pores,and the subtle structural changes effected by ScCO2 fluid in sensitive minerals in reservoirs with a high brittle mineral content also have a positive effect on permeability and storage *** adsorption process has been characterized as consisting of three stages:short-term shrinkage,slow swelling,and stability;an expansion equation has been proposed for CO2/CH4 that incorporates competitive adsorption,collision desorption,and impingement ***2 fracturing has been found to be more effective than hydraulic fracturing for dense reservoirs and more effective at linking up pore-micro-fissure-fracture systems.

关键词： Shale gas Supercritical CO2 Adsorption/desorption Physical properties Geological sequestration

CYP27A1 mutation in a case of cerebrotendinous xanthomatosis:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第18期10卷 6168-6174页

作者： Zhao-Ran Li Yu-Ling zhou Qi Jin Yin-Yin xie Hong-Mei meng Department of Neurology The First Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina

BACKGROUND Cerebrotendinous xanthomatosis(CTX)is a rare autosomal recessive metabolic disease caused by mutations in CYP27 *** has a low incidence rate,insidious onset,and diverse clinical *** can be easily misdiagnosed and can go unrecognized by clinicians,leading to delayed treatment and worsened patient *** SUMMARY A 38-year-old male was admitted to our hospital with a history of unabating unstable posture and difficulty in walking for more than 30 *** based on the patient’s medical history,clinical symptoms,magnetic resonance imaging and gene sequencing results,he was finally diagnosed with *** to the low incidence rate of the disease,clinicians have insufficient knowledge of it,which makes the diagnosis process more tortuous and prolongs the diagnosis *** Prompt diagnosis and treatment of CTX improve patient outcomes.

关键词： Cerebrotendinous xanthomatosis CYP27A1 Sterol 27-hydroxylase c.380G> c.1563dup A Case report

TWO-STAGE ESTIMATION FOR SEEMINGLY UNRELATED NONPARAMETRIC REGRESSION MODELS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2007年第4期20卷 509-520页

作者： Jinhong YOU Shangyu xie Yong zhou Department of Biostatistics University of North Carolina at Chapel Hill Chapel Hill NC 27599-7400 USA. Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080 China

This paper is concerned with the estimating problem of seemingly unrelated （SU） non- parametric regression models. The authors propose a new method to estimate the unknown functions, which is an extension of the two-stage procedure in the longitudinal data framework. The authors show the resulted estimators are asymptotically normal and more efficient than those based on only the individual regression equation. Some simulation studies are given in support of the asymptotic results. A real data from an ongoing environmental epidemiologie study are used to illustrate the proposed procedure.

关键词： Asymptotic normality nonparametrie model seemingly unrelated regression two-stage estimation

Construction of compact RBF network by refining coarse clusters and widths

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第6期20卷 1309-1315页

作者： Zeng Delu zhou Zhiheng xie Shengli School of Electronic and Information Engineering South China Univ. of Technology Guangzhou 510641 P. R. China

It is known that centers, widths, and weights are three mainly considered factors in constructing a radial basis function（RBF） *** paper aims at constructing a compact RBF network with two main *** the first step, the coarse clusters computed from triangle inequalities are refined to obtain the locations of centers by the defined maximum degree spanning tree（MDST）.Meanwhile the coarse widths are *** the second step, a learning algorithm referred to as anisotropic gradient descent method is presented to further refine the above coarse *** of the proposed algorithm show its great performance in times series prediction and classification.

关键词： clustering anisotropic gradient descent radial basis function time series prediction boundary extraction.

Optimal Design of a Main Driving Mechanism for Servo Punch Press Based on Performance Atlases

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2013年第5期26卷 909-917页

作者： zhou Yanhua xie Fugui LIU Xinjun Department of Precision Instruments and Mechanology Tsinghua University Institute of Aircraft Engineering Naval Aeronautical and Astronautical University Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University

The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and energy *** effectively improve the performance and lower the cost,it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices.A new patented main driving mechanism and a new optimal design method are *** the optimal design,the performance indices,i.e.,the local motion/force transmission indices ITI,OTI,good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are *** non-dimensional normalization method is used to get all feasible solutions in dimensional ***,the performance atlases,which can present all possible design solutions,are *** a result,the feasible solution of the mechanism with good motion/force transmission performance is *** the solution can be flexibly adjusted by designer according to the practical design *** proposed mechanism is original,and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

关键词： servo punch press main driving mechanism dimensional optimization transmission index performance atlas

Global minimization of adaptive local image fitting energy for image segmentation

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2014年第2期25卷 307-313页

作者： Guoqi Liu Zhiheng zhou Shengli xie School of Electronic and Information Engineering South China University of Technology School of Automation Guangdong University of Technology

The active contour model based on local image fitting （LIF） energy is an effective method to deal with intensity inhomo- geneities, but it always conflicts with the local minimum problem because LIF has a nonconvex energy function form. At the same time, the parameters of LIF are hard to be chosen for better per- formance. A global minimization of the adaptive LIF energy model is proposed. The regularized length term which constrains the zero level set is introduced to improve the accuracy of the bound- aries, and a global minimization of the active contour model is presented, in addition, based on the statistical information of the intensity histogram, the standard deviation σ with respect to the truncated Gaussian window is automatically computed according to images. Consequently, the proposed method improves the performance and adaptivity to deal with the intensity inhomo- geneities. Experimental results for synthetic and real images show desirable performance and efficiency of the proposed method.

关键词： image segmentation level set adaptive local imagefitting (LIF) energy.

Progresses and Prospects of Asymmetrically Coordinated Single Atom Catalysts for Lithium-Sulfur Batteries

在线全文

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2024年第4期7卷 48-63页

作者： Rong zhou Shaonan Gu meng Guo Shuzheng Xu Guowei zhou Key Laboratory of Fine Chemicals in Universities of Shandong Jinan Engineering Laboratory for Multi-scale Functional MaterialsSchool of Chemistry and Chemical EngineeringQilu University of Technology(Shandong Academy of Sciences)Jinan 250353China

Lithium-sulfur batteries(LSBs)are widely regarded as promising next-generation batteries due to their high theoretical specific capacity and low material ***,the practical applications of LSBs are limited by the shuttle effect of lithium polysulfides(LiPSs),electronic insulation of charge and discharge products,and slow LiPSs conversion reaction ***,the introduction of catalysts into LSBs is one of the effective strategy to solve the issues of the sluggished LiPS *** of their nearly 100%atom utilization and high electrocatalytic activity,single-atom catalysts(SACs)have been widely used as reaction mediators for LSBs’***,the SACs with asymmetric coordination structures have exhibited intriguing electronic structures and superior catalytic activities when compared to the traditional M-N_(4)active *** this review,we systematically describe the recent advancements in the installation of asymmetrically coordinated single-atom structure as reactions catalysts in LSBs,including asymmetrically nitrogen coordinated SACs,heteroatom coordinated SACs,support effective asymmetrically coordinated SACs,and bimetallic coordinated *** noteworthy is the discussion of the catalytic conversion mechanism of LiPSs spanning asymmetrically coordinated ***,a perspective on the future developments of asymmetrically coordinated SACs in LSB applications is provided.

关键词： asymmetrical coordination conversion catalysis Li-S batteries shuttle effect single atom catalysts

Prediction of damage potential in mainshock–aftershock sequences using machine learning algorithms

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第4期23卷 919-938页

作者： zhou zhou Wang meng Han Miao Yu Xiaohui Lu Dagang School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Multi-Functional Shaking Tables Laboratory Beijing University of Civil Engineering and ArchitectureBeijing 100044China College of Civil Engineering Tongji UniversityShanghai 200092China College of Civil Engineering and Architecture Guilin University of TechnologyGuilin 541004China School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China

Assessing the potential damage caused by earthquakes is crucial for a community’s emergency *** this study,four machine learning(ML)methods—random forest,extremely randomized trees,AdaBoost(AB),and gradient boosting(GB)—were employed to develop prediction models for the damage potential of the mainshock(DIMS)and mainshock–aftershock sequences(DIMA).Building structures were modeled using eight single-degree-of-freedom(SDOF)systems with different hysteretic rules.A set of 662 recorded mainshock–aftershock(MS-AS)ground motions was selected from the PEER *** intensity measures(IMs)were chosen to represent the characteristics of the mainshock and *** results revealed that the selected ML methods can well predict the structural damage potential of the SDOF systems,except for the AB *** GB model exhibited the best performance,making it the recommended choice for predicting DIMS and DIMA among the four ML ***,the impact of input variables in the prediction was investigated using the shapley additive explanations(SHAP)*** high-correlation variables were sensitive to the structural period(T).At T=1.0 s,the mainshock peak ground velocity(PGVM)and aftershock peak ground displacement(PGDA)significantly influenced the prediction of *** T increased to 5.0 s,the primary high-correlation factor of the mainshock IMs changed from PGVM to the mainshock peak ground displacement(PGDM);however,the highcorrelation variable of the aftershock IMs remained *** high-correlation factors for DIMS showed trends similar to those of ***,a table summarizing the first and second high-correlation variables for predicting DIMS and DIMA were provided,offering a valuable reference for parameter selection in seismic damage prediction for mainshock–aftershock sequences.

关键词： machine learning mainshock-aftershock damage potential prediction the high-correlation variables SDOF systems

Constitutive parameters identification of thermal barrier coatings using the virtual fields method

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 78-87,I0003页

作者： mengmeng zhou Huimin xie Luming Li School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

Thermal barrier coatings (TBCs) are widely applied in thermal components to protect metallic components. Owing to the complex layered structure of TBCs and difficult preparation of coating, the mechanical characterization of TBCs should be of primary importance. With regard to TBCs, this study deals with the constitutive parameters identification of bi-material. Considering the complex construction and boundary of bi material, the virtual fields method (VFM) was employed in this study. A methodology based on the optimized virtual fields method combined with moire interferometry was proposed for the constitutive parameters identification of bi-material. The feasibility of this method is verified using simulated deformation fields of a two-layer material subjected to three point ben ding loading. As an application, the deformation fields of the TBC specimens were measured by moire interferometry. Then, lhe mechanical parameters of the coating were identified by the proposed method. The identification results indicate that Young's modulus of the TBC top coating is 89.91 GPa, and its Poisson's ratio is 0.23.

关键词： Virtual Fields Method Thermal barrier coatings Mechanical parameters identification Moiré interferometry