检索结果-南通市图书馆

Simulation study of supercritical carbon dioxide jet fracturing for carbonate geothermal reservoir based on fluid-thermo-mechanical coupling model

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2023年第3期20卷 1750-1767页

作者： jian-Xiang Chen rui-Yue Yang Zhong-wei Huang Xiao-Guang Wu Shi-Kun Zhang Hai-Zhu Wang Feng Ma State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China Sinopec Research Institute of Petroleum Engineering Beijing102206China The Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological SciencesShijiazhuang050061HebeiChina Technology Innovation Center of Geothermal&Hot Dry Rock Exploration and Development Ministry of Natural ResourcesShijiazhuang050061HebeiChina

Geothermal energy is a kind of renewable,sustainable and clean energy *** energy is abundant in carbonate ***,low matrix permeability limits its *** super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) *** this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet *** mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh *** physical properties change of sC-CO_(2) with temperature were considered in the numerical *** showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and ***,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water ***,pressure and temperature control the jet field and seepage field of sC-CO_(2) *** the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.

关键词： Carbonate Carbon capture utilization and storage(CCUS) Jet fracturing Coupled model Geothermal reservoir

Hierarchical Crystalline Structures Induced by Temperature Profile in HDPE Bars during Melt Penetration Process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2017年第1期35卷 108-122页

作者： chun-xia zhu rui-yan zhang yan-hao huang wei yang zheng-ying liu jian-ming feng 杨鸣波 College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 China

The hierarchical crystalline morphologies and orientation structures across the thickness direction in high-density polyethylene （HDPE） molded bars were investigated via a novel melt-penetrating processing method named multi-melt multi-injection molding （M3IM）. The samples with various mold temperatures （20, 40 and 60 ℃） were prepared, and the effects of the external temperature profile on the evolution of crystalline microstructures were studied. With scanning electron microscopy （SEM）, the transition of crystalline morphology from ring-banded structure to oriented lamellae was observed with decreasing mold temperature, and the oriented lamellae were formed at the sub-skin layer of the samples at the lowest mold temperature, which was further testified by differential scanning calorimetry （DSC）. With the decline of mold temperature, the degree of orientation, obtained from two-dimensional small angle X-ray scattering （2D-SAXS）, was increased and long periods rose a little. Thus, decreasing mold temperature was beneficial to the formation of orientation structures because the relaxation of chains was weakened.

关键词： Hierarchical structures Orientation Multi-melt multi-injection molding Mold temperature

Damage analysis of POZD coated square reinforced concrete slab under contact blast

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1715-1726页

作者： wei Wang Qing Huo jian-chao Yang jian-hui Wang Xing Wang wei-liang Gao Key Laboratory of Impact and Safety Engineering (Ningbo University)Ministry of EducationNingbo315211ZhejiangChina Institute of Defence Engineering AMS PLALuoyang 471023China Institute of Advanced Energy Storage Technology and Equipment Ningbo UniversityNingbo315211ZhejiangChina

High efficiency, environmental protection and sustainability have become the main theme of the development of the protection engineering, requiring that the components not only meet the basic functions, but also have chemical properties such as acid and alkali corrosion resistance and aging resistance. Polyisocyanate-oxazodone(POZD) polymer has the above characteristics, it also has the advantages of strong toughness, high strength and high elongation. The concrete slab sprayed with POZD material has excellent anti-blast performance. In order to explore the damage characteristics of POZD sprayed concrete slabs under the action of contact explosion thoroughly, the contact explosion test of POZD concrete slabs with different charges were carried out. On the basis of experimental verification,numerical simulation were used to study the influence of the thickness of the POZD on the blast resistance of the concrete slab. According to the test and numerical simulation results that as the thickness of the coating increases, the anti-blast performance of the concrete slab gradually increases,and the TNT equivalent required for critical failure is larger. Based on the above analysis, empirical expressions on normalized crater diameter, the normalized spall diameter and normalized spall diameter are obtained.

关键词： Contact exposion Square reinforced concrete slab POZD coating Numerical simulation

High-fidelity resonant tunneling passage in three-waveguide system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第2期31卷 320-328页

作者： rui-Qiong Ma jian Shi Lin Liu Meng Liang Zuo-Liang Duan wei Gao Jun Dong School of Electronic Engineering Xi'an University of Posts ami TelecommunicationsXi'an 710121China

An N-stage three-waveguide system is proposed to improve the robustness and the fidelity of the resonant tunneling *** analytic solutions to the tunneling dynamics at the output are *** the number of subsystems increases,tunneling efficiency approaches to 100%in a large range and resonant tunneling is robust against variations in the phase mismatch and peak tunneling rate.

关键词： amplitude control resonant tunneling passage robustness

Sparse Signal Recovery via Exponential Metric Approximation

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2017年第1期22卷 104-111页

作者： jian Pan Jun Tang wei Zhu Department of Electronic Engineering Tsinghua University Beijing 100084China

Sparse signal recovery problems are common in parameter estimation, image processing, pattern recognition, and so on. The problem of recovering a sparse signal representation from a signal dictionary might be classified as a linear constraint l_0-quasinorm minimization problem, which is thought to be a Non-deterministic Polynomial-time（NP）-hard problem. Although several approximation methods have been developed to solve this problem via convex relaxation, researchers find the nonconvex methods to be more efficient in solving sparse recovery problems than convex methods. In this paper a nonconvex Exponential Metric Approximation（EMA）method is proposed to solve the sparse signal recovery problem. Our proposed EMA method aims to minimize a nonconvex negative exponential metric function to attain the sparse approximation and, with proper transformation,solve the problem via Difference Convex（DC） programming. Numerical simulations show that exponential metric function approximation yields better sparse recovery performance than other methods, and our proposed EMA-DC method is an efficient way to recover the sparse signals that are buried in noise.

关键词： sparse recovery exponential metric approximation sparsity tolerance DC optimization signal-to-noiseratio

A serum metabolomic analysis for diagnosis and biomarker discovery of primary biliary cirrhosis and autoimmune hepatitis

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2015年第4期14卷 413-421页

作者： jiang-Shan Lian wei Liu Shao-rui Hao De-Ying Chen Yin-Yin Wang jian-Le Yang Hong-Yu Jia jian-Rong Huang Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases State Key Laboratory for Diagnosis and Treatment of Infectious Disease First Affiliated Hospital Zhejiang University School of Medicine Yantai City Hospital for Infectious Diseases

Because of the diversity of the dinical and laboratory manifestations, the diagnosis of autoimmune liver disease （AILD） remains a challenge in clinical practice. The value of metabolomics has been studied in the diagnosis of many diseases. The present study aimed to determine whether the metabolic profiles, based on ultraperformance liquid chromatography-mass spectrometry （UPLC-MS）, differed between autoimmune hepatitis （AIH） and primary biliary cir- rhosis （PBC）, to identify specific metabolomic markers, and to establish a model for the diagnosis of AIH and PBC. METHODS： Serum samples were collected from 20 patients with PBC, 19 patients with AIH, and 25 healthy individuals. UPLC-MS data of the samples were analyzed using principal component analysis, partial least squares discrimination analysis and or- thogonal partial least squares discrimination analysis. RESULTS： The partial least squares discrimination analysis model （R2y=0.991, Q2=0.943） was established between the AIH and PBC groups and exhibited both sensitivity and speci- ficity of 100%. Five groups of biomarkers were identified, in- eluding bile acids, free fatty acids, phosphatidylcholines, lyso- lecithins and sphingomyelin. Bile acids significantly increased in the AIH and PBC groups compared with the healthy con- trol group. The other biomarkers decreased in the AIH andPBC groups compared with those in the healthy control group. In addition, the biomarkers were downregulated in the AIH group compared with the PBC group. CONCLUSIONS： The biomarkers identified revealed the pathophysiological changes in AILD and helped to discrimi- nate between AIH and PBC. The predictability of this method suggests its potential application in the diagnosis of AILD.

关键词： autoimmune liver disease biomarkers metabolomics autoimmune hepatitis primary biliary cirrhosis overlap syndrome

Identification of reduced-order model for an aeroelastic system from flutter test data

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第1期30卷 337-347页

作者： Tang wei Wu jian Shi Zhongke School of Automation Northwestern Polytechnical University

Recently, flutter active control using linear parameter varying（LPV） framework has attracted a lot of attention. LPV control synthesis usually generates controllers that are at least of the same order as the aeroelastic models. Therefore, the reduced-order model is required by synthesis for avoidance of large computation cost and high-order controller. This paper proposes a new procedure for generation of accurate reduced-order linear time-invariant（LTI） models by using system identification from flutter testing data. The proposed approach is in two steps. The well-known poly-reference least squares complex frequency（p-LSCF） algorithm is firstly employed for modal parameter identification from frequency response measurement. After parameter identification,the dominant physical modes are determined by clear stabilization diagrams and clustering technique. In the second step, with prior knowledge of physical poles, the improved frequencydomain maximum likelihood（ML） estimator is presented for building accurate reduced-order model. Before ML estimation, an improved subspace identification considering the poles constraint is also proposed for initializing the iterative procedure. Finally, the performance of the proposed procedure is validated by real flight flutter test data.

关键词： Aeroelastic system Flutter test Maximum likelihood Reduced-order model Subspace identification

Fe、Ir掺杂MoS_(2)表面对N_(2)气敏吸附与解离反应性能提升的第一性原理研究

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第1期42卷 13-19页

作者：肖香珍胡林峰张建伟河南科技学院新乡453003

基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说... 详细信息

基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说明掺杂之后对N_(2)表现出略好的吸附性能.差分电荷密度分析表明,N_(2)吸附后,掺杂Fe、Ir原子与两个N原子之间电荷有所增加,N-N键之间的区域电荷密度减少,N-N键的强度减弱.态密度计算结果发现,N_(2)在吸附过程中,主要是N原子的2p_(y)、2p_(z)轨道与Ir的5d_(xy)和5d_(z^(2))以及Fe的3d_(xy)和3d_(z^(2))发生杂化作用.通过分析解离活化能,N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离需要活化能均较高,且远大于在相应掺杂表面的吸附能,说明N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离应该表现为分子吸附或脱附.

关键词： Fe、Ir 掺杂单层MoS_(2) N_(2) 吸附与解离活化能密度泛函理论

Influence of mechanical damage generated by small space debris on electrostatic discharge

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第3期59卷 533-539页

作者： CAI Ming Hui LI Hong wei HAN jian wei National Space Science Center Chinese Academy of Sciences

Recent studies have indicated that hypervelocity impacts by meteoroids and space debris can induce spacecraft anomalies. However, the basic physical process through which space debris impacts cause anomalies is not entirely clear. Currently, impact-generated plasma is thought to be the primary cause of electrical spacecraft anomalies, while the effects of impact-generated mechanical damage have rarely been researched. This paper presents new evidence showing that impact-generated mechanical damage strongly influences electrostatic discharge. Hypervelocity impact experiments were conducted in a plasma drag particle accelerator, using particles with diameters of 200–500 ?m and velocities of 2–7 km/s. The impact-generated mechanical damage on a specimen surface was measured by a stereoscopic microscope and 3D Profilometer and it indicated that microscopic irregularities around the impact crater could be responsible for local electric field enhancement. Furthermore, the influence of impact-generated mechanical damage on electrostatic discharge was simulated in an inverted potential gradient situation. The experimental results show that the electrostatic discharge voltage threshold was significantly reduced after the specimen was impacted by particles.

关键词： Electrostatic discharge Small space debris Inverted potential gradient Spacecraft charging