期刊文献+
共找到1,642篇文章
< 1 2 83 >
每页显示 20 50 100
Bidirectional relationship between diabetes mellitus and depression:Mechanisms and epidemiology
1
作者 Yun Liu Shi-Yan Huang +3 位作者 De-Le Liu Xin-Xing Zeng Xiao-Rui Pan Jie Peng 《World Journal of Psychiatry》 SCIE 2024年第10期1429-1436,共8页
Diabetes mellitus and depression exhibit a complex bidirectional relationship that profoundly impacts patient health and quality of life.This review explores the physiological mechanisms,including inflammation,oxidati... Diabetes mellitus and depression exhibit a complex bidirectional relationship that profoundly impacts patient health and quality of life.This review explores the physiological mechanisms,including inflammation,oxidative stress,and neu-roendocrine dysregulation,that link these conditions.Psychosocial factors such as social support and lifestyle choices also contribute significantly.Epidemiological insights reveal a higher prevalence of depression among diabetics and an in-creased risk of diabetes in depressed individuals,influenced by demographic variables.Integrated management strategies combining mental health asse-ssments and personalized treatments are essential.Future research should focus on longitudinal and multi-omics studies to deepen understanding and improve therapeutic outcomes. 展开更多
关键词 Diabetes DEPRESSION mechanISMS EPIDEMIOLOGY Bidirectional relationship
下载PDF
Review on mechanisms and structure-activity relationship of hypoglycemic effects of polysaccharides from natural resources 被引量:5
2
作者 Xiaolong Ji Jianhang Guo +3 位作者 Tengzheng Cao Tingting Zhang Yanqi Liu Yizhe Yan 《Food Science and Human Wellness》 SCIE CSCD 2023年第6期1969-1980,共12页
Diabetes mellitus(DM)is a common multifactorial disease,causing various complications,such as chronic metabolism.The current therapies for diabetes mellitus are commercial diabetic drugs that have different definite s... Diabetes mellitus(DM)is a common multifactorial disease,causing various complications,such as chronic metabolism.The current therapies for diabetes mellitus are commercial diabetic drugs that have different definite side effect.However,polysaccharides mainly extracted from natural resources,have advantages of safety,accessibility,and anti-diabetic potential.We have summarized recent research of natural polysaccharides with hypoglycemic activities,focusing on different pharmacological mechanisms in various cell and animal models.The relationships of structure-hypoglycemic effect are also discussed in detail.This review could provide a comprehensive perspective for better understanding on development and mechanism of natural polysaccharides against diabetes mellitus,which have been required by clinical studies yet. 展开更多
关键词 POLYSACCHARIDES Hypoglycemic effect mechanISMS Structure-activity relationship
下载PDF
Screening hepatoprotective effective components of Lonicerae japonica Flos based on the spectrum-effect relationship and its mechanism exploring 被引量:1
3
作者 Song Wang Lin Yang +4 位作者 Ajiao Hou Songtao Liu Liu Yang Haixue Kuang Hai Jiang 《Food Science and Human Wellness》 SCIE CSCD 2023年第1期283-294,共12页
Lonicerae japonicae Flos(LF)is a kind of healthcare food with hepatoprotective function.This study was designed to explore the spectrum-effect relationships between UPLC fingerprints and the hepatoprotective effects o... Lonicerae japonicae Flos(LF)is a kind of healthcare food with hepatoprotective function.This study was designed to explore the spectrum-effect relationships between UPLC fingerprints and the hepatoprotective effects of LF.Fingerprints of ten batches of LF were established by UPLC-PDA.The inhibitory levels of AST and ALT were used as pharmacological indexes,and secoxyloganin,isochlorogenic acid A and isochlorogenic acid C were screened as hepatoprotective active compounds by grey relational analysis(GRA)and partial least squares regression analysis(PLSR).Caspase-3 was obtained by network pharmacology as a key target of hepatoprotective active compounds.Molecular docking is used to explore the interaction between small molecules and proteins.This work provided a general model of the combination of UPLC-PDA and hepatoprotective effect to study the spectrum-effect relationship of LF,which can be used to considerable methods and insight for the fundamental research of the material basis of similar healthcare food. 展开更多
关键词 Lonicerae japonicae Flos Hepatoprotective effect Spectrum-effect relationship Molecular docking mechanISM
下载PDF
Mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device 被引量:1
4
作者 Xin Xu Na Xu +3 位作者 Wei Zhang Junwen Wang Yao Li Chen Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第12期37-48,共12页
Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow... Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification. 展开更多
关键词 Gas-liquid microreactor Annular flow Mass transfer mechanism Mass transfer relationship Multi-objective particle swarm optimization
下载PDF
Mechanical Properties and Constitutive Relationship of the High-Durable Parallel Strand Bamboo 被引量:3
5
作者 Yousef Y.Sewar Zhancheng Zhang +4 位作者 Xinmiao Meng Mohammed Y.Wahan Hanxiao Qi Qahtan M.Al-Shami Shijiao Luo 《Journal of Renewable Materials》 SCIE EI 2022年第1期219-235,共17页
Engineered bamboo has recently received lots of attention of civil engineers and professional researchers due to its better mechanical performance than that of softwood timber.Parallel strand bamboo is one important p... Engineered bamboo has recently received lots of attention of civil engineers and professional researchers due to its better mechanical performance than that of softwood timber.Parallel strand bamboo is one important part of engineered bamboo for its excellent durable performance compared to the laminated veneer bamboo.The required curing temperature in hot-pressing process is usually higher than 120°C to reduce the content of nutri-tional ingredients and hemy cellulose,and to avoid the decay from the environment and insects.Nonetheless,the appearance of engineered bamboo gets darker with the increase of temperature during the hot-pressing process.In order to minimize the color deepening while maintaining the durability,a high-durable parallel strand bamboo(HPSB)with relative high hot-pressing temperature(140°C)was produced and tested.The present study inves-tigates the mechanical performance through tension,compression,shear and bending tests.The experimental behavior of the specimens was identified,including the failure mode and load-displacement relationship.It was demonstrated that the HPSB material had better mechanical performance parallel to grain,making it as a considerable structural material.The average elastic modulus parallel to grain was 14.1 GPa,and the tensile and compressive strengths were 120.7 MPa and 121.0 MPa,respectively.The tension perpendicular to grain should be avoided in the practical application due to the lower strength and elastic modulus.Two stress-strain relationships of tension and compression parallel to grain,including three-linear and quadratic function models,were proposed and compared with the experimental results.The three-linear model was then applied to the finite element model.The finite element analysis using ANSYS software was conducted to validate the feasibility of the constitutive relationship.The quadratic function model showed better agreement with the experimental results,but the three-linear relationship was also precise enough to analyze the bending tests of HPSB material,whereas being less accurate to describe the elastic-plastic compression behavior. 展开更多
关键词 Engineered bamboo bamboo scrimber mechanical property constitutive relationship finite element model
下载PDF
Advances in Research of Biological Activity,Action Mechanism and Structure-Activity Relationship of Lentinan
6
作者 Jiawen LI Chao ZHAO +2 位作者 Xiaojian GONG Huaguo CHEN Xin ZHOU 《Asian Agricultural Research》 2023年第12期28-38,共11页
Lentinula edodes is the second largest edible mushroom in the world and is widely used as food and medicine.Modern research shows that lentinan(LNT)is the main active component of L.edodes.It has anti-cancer,treatment... Lentinula edodes is the second largest edible mushroom in the world and is widely used as food and medicine.Modern research shows that lentinan(LNT)is the main active component of L.edodes.It has anti-cancer,treatment of diabetes,intestinal protection,anti-inflammatory,anti-oxidation,anti-aging,hepatoprotective,immune-regulating effects.In this review,the biological activity,action mechanism and structure-activity relationship of LNT in recent years are reviewed.On this basis,the existing problems were discussed,and the future research and application of LNT were prospected.Finally,it is hoped that this review will promote the in-depth study of LNT and provide a reference for its development as a drug and functional food. 展开更多
关键词 LENTINAN BIOLOGICAL ACTIVITIES Action mechanism STRUCTURE-ACTIVITY relationship
下载PDF
Food-derived bio-functional peptides for the management of hyperuricemia and associated mechanism
7
作者 Yanxin Wang Mingxia Ma +6 位作者 Yumeng Huang Siqing Fan Jie Peng Shiming Li Xiurong Su Yanbo Wang Chenyang Lu 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第4期1767-1786,共20页
Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high ac... Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high activity and few adverse effects,food-derived active peptides used as functional foods against hyperuricemia have attracted increasing attention.This article aims to focus on the challenge associated with peptide-specific preparation methods development,functional components identification,action mechanism(s)clarification,and bioavailability improvement.The current review proposed recent advances in producing the food-derived peptides with high anti-hyperuricemia activity by protein source screening and matched enzymatic hydrolysis condition adjusting,increased the knowledge about strategies to search antihyperuricemia peptides with definite structure,and emphasized the necessity of combining computer-aided approaches and activity evaluations.In addition,novel action mechanism mediated by gut microbiota was discussed,providing different insights from classical mechanism.Moreover,considering that little attention was paid previously on the structure-activity relationships of anti-hyperuricemia peptides,we collected the sequences from published studies and make a preliminary summary about the structure-activity relationships,which in turn provided guides for enzymatic hydrolysis optimization and bioavailability improvement.Hopefully,this article could promote the development,application and commercialization of food-derived anti-hyperuricemia peptides in the future. 展开更多
关键词 HYPERURICEMIA PEPTIDE Enzyme hydrolysis mechanISM Structure-activity relationship BIOAVAILABILITY
下载PDF
A Large-Scale Group Decision Making Model Based on Trust Relationship and Social Network Updating
8
作者 Rongrong Ren Luyang Su +2 位作者 Xinyu Meng Jianfang Wang Meng Zhao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期429-458,共30页
With the development of big data and social computing,large-scale group decisionmaking(LGDM)is nowmerging with social networks.Using social network analysis(SNA),this study proposes an LGDM consensus model that consid... With the development of big data and social computing,large-scale group decisionmaking(LGDM)is nowmerging with social networks.Using social network analysis(SNA),this study proposes an LGDM consensus model that considers the trust relationship among decisionmakers(DMs).In the process of consensusmeasurement:the social network is constructed according to the social relationship among DMs,and the Louvain method is introduced to classify social networks to form subgroups.In this study,the weights of each decision maker and each subgroup are computed by comprehensive network weights and trust weights.In the process of consensus improvement:A feedback mechanism with four identification and two direction rules is designed to guide the consensus of the improvement process.Based on the trust relationship among DMs,the preferences are modified,and the corresponding social network is updated to accelerate the consensus.Compared with the previous research,the proposedmodel not only allows the subgroups to be reconstructed and updated during the adjustment process,but also improves the accuracy of the adjustment by the feedbackmechanism.Finally,an example analysis is conducted to verify the effectiveness and flexibility of the proposed method.Moreover,compared with previous studies,the superiority of the proposed method in solving the LGDM problem is highlighted. 展开更多
关键词 Large-scale group decision making social network updating trust relationship group consensus feedback mechanism
下载PDF
Mechanical Properties of Living Adherent Cells :Relationship with Structure and Function
9
作者 R. FODIL S. Féréol +3 位作者 E. PLANUS V.M. LAURENT B. LOUIS D. ISABEY 《生物医学工程学杂志》 EI CAS CSCD 北大核心 2005年第S1期9-10,共2页
关键词 relationship with Structure and Function mechanical Properties of Living Adherent Cells PBM CELL
下载PDF
Experimental study on mechanical properties of reactive powder concrete 被引量:8
10
作者 李莉 郑文忠 卢姗姗 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第6期795-800,共6页
The axial compressive strength,axial tensile strength,elastic modulus,poisson ratio and stress-strain relationship of RPC are obtained by compressive tests and tensile tests of RPC prism.Mathematical models of axial c... The axial compressive strength,axial tensile strength,elastic modulus,poisson ratio and stress-strain relationship of RPC are obtained by compressive tests and tensile tests of RPC prism.Mathematical models of axial compressive and axial tensile stress-strain relationship are established,from which the equivalent coefficient of compressive and tensile stress diagram of cross-section in RPC beam are deduced.The results provide the theory basis for the design of RPC structure and the wider popularization of RPC. 展开更多
关键词 RPC mechanical properties uniaxial stress-strain relationship curve equivalent coefficent of stress diagram
下载PDF
Mechanical Behaviors and Microstructural Characteristics of TC11 Alloy during Hot Deformation 被引量:4
11
作者 孙新军 白秉哲 +1 位作者 顾家林 陈南平 《Rare Metals》 SCIE EI CAS CSCD 2000年第2期101-109,共9页
The mechanical behaviors and the microstructural characteristics of TC11 alloy with quenched martensite microstructure during hot compressive deformation were investigated. It shows that at various temperatures and st... The mechanical behaviors and the microstructural characteristics of TC11 alloy with quenched martensite microstructure during hot compressive deformation were investigated. It shows that at various temperatures and strain rates, the stress strain curves firstly exhibit strain hardening, then strain softening and finally reach the steady deformation state; in the meanwhile, the initial lamellar microstructure is transformed into the equiaxed and uniform one through dynamic recrystallization. It shows that the present TC11 alloy has different Z D relationships in relatively lower temperature (RLT) range and relatively higher temperature (RHT) range, which is believed to be due to different deformation activation energies. During RHT deformation, dynamic recrystallization occurs in both α phases and β phases, but during RLT deformation, dynamic recrystallization only occurs in α phases and in the meanwhile β phases undergo a process of precipitation and growth. 展开更多
关键词 Z D relationship Hot deformation TC11 alloy mechanical behaviors MICROSTRUCTURE
下载PDF
Effect of WC grain size on mechanical properties and microstructures of cemented carbide with medium entropy alloy Co-Ni-Fe binder 被引量:5
12
作者 QIAN Cheng LI Kun +3 位作者 GUO Xue-yi LIU Bin LONG Zheng-yi LIU Yong 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第4期1146-1157,共12页
For developing new binder phase with high performance, Co-Ni-Fe alloy was used as binder in cemented carbides. The mechanical properties of WC-CoNiFe and WC-Co cemented carbides with different grain sizes were studied... For developing new binder phase with high performance, Co-Ni-Fe alloy was used as binder in cemented carbides. The mechanical properties of WC-CoNiFe and WC-Co cemented carbides with different grain sizes were studied. The results show that the reprecipitation of WC-CoNiFe is inhibited compared with that of WC-Co during sintering process, and the grains in WC-CoNiFe cemented carbides are more of smooth shape, resulting in a slightly lower hardness and higher transverse rupture strength. With the increase of the grain size, the hardness of the two cemented carbides decreases, and the transverse rupture strength increases. However, the slope values of K in Hall-Petch relationship are higher in WC-CoNiFe than those in WC-Co, indicating the high toughness of medium entropy alloy Co-Ni-Fe. 展开更多
关键词 cemented carbides mechanical properties dissolution-reprecipitation Hall-Petch relationship medium entropy alloy
下载PDF
Effects of Frost-damage on Mechanical Performance of Concrete 被引量:1
13
作者 李安邦 徐善华 WANG Youde 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第1期129-135,共7页
The aim of this study is to provide the quantificational change laws of strength,stiffness,and deformation capacity of frost-damaged concrete relating to a united index,the data were obtained by different researchers.... The aim of this study is to provide the quantificational change laws of strength,stiffness,and deformation capacity of frost-damaged concrete relating to a united index,the data were obtained by different researchers.Then the index of relative compressive strength(RCS) was introduced as the indicator of frost damage and a large number of mechanical performance testing data of frost-damaged concrete were collected and analyzed.By curve fitting,the correlations between RCS and the initial elastic modulus,the strain at peak compressive stress,and biaxial compressive strength,and tensile strength,and the strain at peak tensile stress were established.Thereafter,the analytical stress-strain response of frost-damaged concrete under monotonic loading was presented using RCS and compared with that of the experimental data.Moreover,an isotropic elastoplastic damage model of frost-damaged concrete subjected to repeated loading was established.Finally,we can systematically estimate the effects of frost-damage on the mechanical performance of concrete,which can be provided for the numerical simulation of frost-damaged concrete structures. 展开更多
关键词 CONCRETE frost-damage mechanical performance stress-strain relationship relative compressive strength
下载PDF
Macroscopic and microscopic mechanical behaviors of climbing tendrils 被引量:1
14
作者 Q.Guo J.J.Dong +3 位作者 Y.Liu X.H.Xu Q.H.Qin J.S.Wang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第3期702-710,共9页
Tendril-bearing climbing plants must recur to the tendril helices with chiral perversion or dual chirality for climbing and to obtain sun exposure. Despite researchers' prolonged fascination with climbing tendrils... Tendril-bearing climbing plants must recur to the tendril helices with chiral perversion or dual chirality for climbing and to obtain sun exposure. Despite researchers' prolonged fascination with climbing tendrils since Darwin's time and even earlier, why the soft and slender tendrils can bear heavy loads such as the self-weight of a plant or additional load caused by rain remains elusive. In this paper, we take towel gourd tendrils as an example and investigate the macroscopic and microscopic mechanical behaviors of tendrils through experiments and simulations. Our study indicates that the tendril filament exhibits rubber-like hyperelastic behaviors and can particularly endure large elongation, which is mainly attributed to the superelasticity of the cellulose fibril helix contained in the cell wall. Combination of the tendril helical structure with dual chirality or chiral perversion at a macroscale and a cellulose filament helix at a subcellular level creates superior elasticity for biological species relying on support and climbing. This study provides deep insight into the structure-property relationship of climbing tendrils, and the relationship is useful for the bioinspired design of composite systems with superior elasticity. 展开更多
关键词 CLIMBING TENDRIL mechanical behaviors STRUCTURE-PROPERTY relationship Large ELONGATION
下载PDF
Influence of Carbonation on Mechanical Properties of Concrete 被引量:1
15
作者 梁发云 陈龙珠 李检保 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第1期85-88,共4页
As one of the most important factors that determine the lifespan of a reinforced concrete structure, carbonation not only corrodes the reinforcing steel, but also changes the mechanical properties of concrete. For bet... As one of the most important factors that determine the lifespan of a reinforced concrete structure, carbonation not only corrodes the reinforcing steel, but also changes the mechanical properties of concrete. For better understanding the performance of carbonated concrete structure, it is necessary to study the mechanical properties of carbonated concrete. The strees strain relationship of carbonated concrete was analyzed on the basis of experiments. The specimens were made by means of accelerated carbonation and then compressed on the testing machine. Some very important characteristics of carbonated concrete were revealed by the testing results. In addition, a useful constitutive model of carbonated concrete, which proved to be suitable for analyzing carbonated concrete members, was established in this research. 展开更多
关键词 CARBONATION CONCRETE ACCELERATION mechanical properties stress strain relationship
下载PDF
Microstructural evolution and its effect on mechanical properties in different regions of 2219-C10S aluminum alloy TIG-welded joint 被引量:1
16
作者 Deng-kui ZHANG Ai-ping WU +6 位作者 Yue ZHAO Ji-guo SHAN Zhan-dong WAN Guo-qing WANG Jian-ling SONG Zhong-ping ZHANG Xian-li LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第10期2625-2638,共14页
Microstructural evolution and its effect on mechanical properties in different regions of 2219-C10S aluminum alloy tungsten inert gas(TIG)welded joint were analyzed in detail.In weld zone(WZ),α+θeutectic structure f... Microstructural evolution and its effect on mechanical properties in different regions of 2219-C10S aluminum alloy tungsten inert gas(TIG)welded joint were analyzed in detail.In weld zone(WZ),α+θeutectic structure formed at grain boundaries with no precipitates inside the grains.In partially melted zone(PMZ),symbiotic eutectic or divorced eutectic formed at grain boundaries and needle-likeθ′phases appeared in the secondary heated zone.In over aged zone(OAZ),the coarsening and dissolution ofθ′phases occurred and mostθ′phases transformed intoθphases.In general heat affected zone(HAZ),θ′phases coarsened.Factors such as the strengthening phases,the grain size,the Cu content in matrix and the dislocation density can affect the mechanical properties in different regions of the joint.Moreover,a model describing the relationship between mechanical properties of the material and the volume fraction of precipitates,the average diameter of precipitates and the concentration of soluble elements was proposed. 展开更多
关键词 2219-C10S aluminum alloy tungsten inert gas arc welding microstructural evolution mechanical properties relationship model
下载PDF
Tension-compression asymmetry and corresponding deformation mechanism in ZA21 magnesium bars with bimodal structure 被引量:2
17
作者 Yujiao Wang Yun Zhang Haitao Jiang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第1期92-103,共12页
We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bim... We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression,respectively,which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa,respectively.Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T-C asymmetry.However,due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression,the bimodal structure possesses a lower T-C asymmetry(0.68)compared to the uniform structure(0.56).Multiple extension twins occur during deformation,and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains.Furthermore,the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains. 展开更多
关键词 bimodal structure deformation mechanism Hall-Petch relationship tension-compression asymmetry twin variant selection
下载PDF
Failure mechanism and influencing factors of cement sheath integrity under alternating pressure 被引量:1
18
作者 Kuan-Hai Deng Nian-Tao Zhou +4 位作者 Yuan-Hua Lin Yan-Xian Wu Jie Chen Chang Shu Peng-Fei Xie 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2413-2427,共15页
The failure of cement sheath integrity can be easily caused by alternating pressure during large-scale multistage hydraulic fracturing in shale-gas well.An elastic-plastic mechanical model of casing-cement sheath-form... The failure of cement sheath integrity can be easily caused by alternating pressure during large-scale multistage hydraulic fracturing in shale-gas well.An elastic-plastic mechanical model of casing-cement sheath-formation(CSF)system under alternating pressure is established based on the Mohr-Coulomb criterion and thick-walled cylinder theory,and it has been solved by MATLAB programming combining global optimization algorithm with Global Search.The failure mechanism of cement sheath integrity is investigated,by which it can be seen that the formation of interface debonding is mainly related to the plastic strain accumulation,and there is a risk of interface debonding under alternating pressure,once the cement sheath enters plasticity whether in shallow or deep well sections.The matching relationship between the mechanical parameters(elastic modulus and Poisson's ratio)of cement sheath and its integrity failure under alternating pressure in whole well sections is studied,by which it has been found there is a“critical range”in the Poisson's ratio of cement sheath.When the Poisson's ratio is below the“critical range”,there is a positive correlation between the yield internal pressure of cement sheath(SYP)and its elastic modulus.However,when the Poisson's ratio is above the“critical range”,there is a negative correlation.The elastic modulus of cement sheath is closely related to its Poisson's ratio,and restricts each other.Scientific and reasonable matching between mechanical parameters of cement sheath and CSF system under different working conditions can not only reduce the cost,but also protect the cement sheath integrity. 展开更多
关键词 Casing-cement sheath-formation system mechanical model Matching relationship Cement sheath integrity Critical range mechanical parameters
下载PDF
Analysis of Orientation Relationships,Carbon Partitioning and Strengthening Mechanism of a Novel Ultrahigh Strength Steel
19
作者 LIU Heping YANG Hengzhe +2 位作者 SUN Fenger LIU Langlang ZHOU Diaoyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2022年第4期692-698,共7页
The orientation relationships,carbon partitioning and strengthening mechanism of a novel ultrahigh strength steel were analyzed in depth during the complex process of heat treatment.The experimental results reveal tha... The orientation relationships,carbon partitioning and strengthening mechanism of a novel ultrahigh strength steel were analyzed in depth during the complex process of heat treatment.The experimental results reveal that the(011)α//()γ,[100]α//[011]γ orientation relationships can be drawn between martensite and retained austenite.The position and angle of martensite and retained austenite are shown more clearly from the stereographic projections.Moreover,the calculated results show that the carbon content near the austenite interface is the highest in the shorter carbon allocation time.With the further increase of time,its carbon content gradually decreases.Furthermore,a model of the relationship between yield strength and strengthening mechanism was established.It was proved that the main strengthening components contributing to the yield strength include Orowan strengthening,grain-size strengthening and dislocation hardening.The main strengthening mechanism of steel in this experiment is dislocation strengthening. 展开更多
关键词 quenching and partitioning orientation relationships carbon partitioning strengthening mechanism laser additive manufacturing
下载PDF
Interaction Relationship Between Corporate Social Responsibility and Corporate Performance:Evidence from 201 Chinese Listed Companies and Preliminary Study of Its Underlying Mechanism
20
作者 ZHANG Sirui 《International English Education Research》 2019年第2期90-93,共4页
Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performa... Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performance and then adopts other mediation variables to explain the underlying mechanism.The empirical analyses are performed on a sample of 201 listed Chinese firms.The result shows that CSR has a weak negative impact on corporate perfbnnance while being positively influenced by corporate performance significantly.Further study finds the reason may be CSR requires financial support,but has little to do with increasing shareholder wealth. 展开更多
关键词 CORPORATE social responsibility CORPORATE performance INTERACTION relationship mechanISM Eamings per share
下载PDF
上一页 1 2 83 下一页 到第
使用帮助 返回顶部