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Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

《结构与土木工程前沿(英文)》   页码 1326-1340 doi: 10.1007/s11709-023-0014-x

摘要: Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

关键词: strain relationship concrete    

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿(英文)》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要: Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词: gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

Mapping the structure-activity relationship of

Worawan PANPIPAT, Hasene KESKIN, Zheng GUO

《化学科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 105-113 doi: 10.1007/s11705-015-1502-x

摘要: The phase behavior of twelve synthesized -sitosteryl fatty acid esters with acyl moieties with different chain lengths (C2:0-C18:0) and different degrees of unsaturation (C18:1-C18:3) were investigated in pure and mixed Langmuir monolayers with phospholipids. The surface-pressure isotherms showed that short chain -sitosteryl fatty acid esters gave smaller mean molecular areas and had decreased monolayer stability and the long chain steryl esters did not produce collapsed plateaus. All the steryl esters displayed strong condensing effects, but there was a pronounced structural dependency: medium chain esters (C8 and C10) were less efficient than short and long chain esters. Atomic force microscopy imaging demonstrated that monolayers mixed with dipalmitoyl phosphatidylcholine (DPPC) displayed both DPPC-rich and steryl lipid-rich domains. However, the height and area differences between the two phases and the roughness and morphologic patterns were very dependent on the steryl lipid concentrations as well as the length, the degree of unsaturation and the molecular conformations of the acyl segments. These findings not only provide a better understanding of the interactions between phytosteryl hydrophobic derivatives and biomembranes, but also may be of general use for the design and engineering of phytosterol structural derivations for specific food and pharmaceutical applications.

关键词: β-sitosteryl fatty acid esters     dipalmitoyl phosphatidylcholine     Langmuir monolayer     condensing effect     structure-activity relationship    

Property-performance relationship of core-shell structured black TiO photocatalyst for environmental

《环境科学与工程前沿(英文)》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1711-3

摘要:

● Properties and performance relationship of CSBT photocatalyst were investigated.

关键词: Black TiO2     Core-shell structure     Property-performance relationship     Agro-industrial effluent     Environmental remediation    

Stress-strain relationship with soil structural parameter of collapse loess

SHAO Shengjun, YU Qinggao, LONG Jiyong

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 293-293 doi: 10.1007/s11709-008-0100-0

Stress-strain relationship with soil structural parameters of collapse loess

SHAO Shengjun, LONG Jiyong, YU Qinggao

《结构与土木工程前沿(英文)》 2008年 第2卷 第2期   页码 151-160 doi: 10.1007/s11709-008-0020-z

摘要: Through the tri-axial shearing tests of unsaturated intact loess and based on the concept of comprehensive soil structural potential, this paper reveals the changing laws of soil structural property under the tri-axial stress conditions and establishes a mathematical expression equation of structural parameters, whereby reflecting the effects of unsaturated loess water content, stress and strain states, which is introduced into the shearing stress and shearing strain relation to obtain the structural stress-strain relation. The tests reveal that the loess dilatancy is of shearing contraction and shearing expansion, whereby indicating that there is a good linear relation between the stress ratio and shearing expansion strain ratio. The larger consolidation confining pressure is, the larger the stress of shearing contraction and expansion critical point is; and the larger water content is, the smaller the strain ratio of shearing contraction and expansion critical point is. Finally, the constitutive model is established to reflect the variation in loess structure, stress-strain softening and hardening, and shearing contraction and shearing expansion features. Through the comparative analysis, the stress-strain curves described by the constitutive relationship are found to be in good conformity with test results, whereby testing the rationality of the model in this paper.

关键词: hardening     shearing expansion     unsaturated     structural property     mathematical expression    

Relationship between expression of hepatocyte grow factor and apoptosis of trophoblasts in hypertensive

OUYANG Shan, ZHANG Qinghua, QIAO Fuyuan

《医学前沿(英文)》 2007年 第1卷 第4期   页码 386-389 doi: 10.1007/s11684-007-0075-6

摘要: The aim of this study was to investigate the expression of hepatocyte growth factor (HGF) and Fas in placentas of uncomplicated pregnant women and those with hypertensive disorder complicating pregnancy (HDCP), and elucidate the possible relationship between HGF and apoptosis of trophoblasts. Reverse transcription-polymerase chain reaction (RT-PCR) was undertaken to examine the concentration of HGF mRNA and Fas mRNA obtained from 34 cases of HDCP and 30 cases of uncomplicated pregnancy. The expression of HGF mRNA in mild preeclampsia, severe preeclampsia and eclampsia cases was significantly lower than that in the uncomplicated cases (0.43±0.12, 0.38±0.09, 0.19±0.17 versus 0.67±0.19, <0.05), while the expression of Fas mRNA in mild preeclampsia, severe preeclampsia and eclampisa cases was significantly higher than that in the uncomplicated cases (1.58±0.26, 2.96±0.14, 5.98±1.17 versus 1.01±0.36, <0.05). For HGF mRNA and Fas mRNA, there was no difference between gestational hypertension cases and control cases. Decreased HGF mRNA or increased Fas mRNA was found along with the progress of HDCP. Negative correlation was found between the expressions of HGF and Fas. These results indicate that HGF inhibits the apoptosis mediated by Fas, and the reduced expression of HGF in HDCP may be responsible for the apoptosis of trophoblasts.

关键词: pregnancy     concentration     possible relationship     responsible     hepatocyte    

Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

《结构与土木工程前沿(英文)》 2008年 第2卷 第2期   页码 184-188 doi: 10.1007/s11709-008-0029-3

摘要: Adopting the ASTM C666 quick freeze-thaw method, freeze-thaw tests with the number of freeze-thaw cycles being 0, 100, 150, 200, 250, and 300, were carried out on eighteen concrete prism specimens, the frost-resistant level of which, reaches D300 grade. The internal micro-structures of these specimens were observed by means of scanning electron microscopy (SEM) in order to detect damages caused by the freeze-thaw action. Afterwards these frozen-thawed specimens were tested on monotonic axial load; stress-strain testing curves after the freeze-thaw action were obtained. The testing results show that with the increasing time of freeze-thaw cycles, both the internal micro-structures and the basic mechanical parameters, including the ultimate bearing capacity, the Poisson ratio and the modulus of elasticity, degenerate in various degrees. Finally, stress-strain theoretical curvilinear equations and correlated parameters relating to the loss of relative dynamic modulus of elasticity were proposed. These results provide great reference for further research on the behavior and the calculation model of concrete structures in a freeze-thaw environment.

关键词: stress-strain theoretical     freeze-thaw     capacity     reference     eighteen concrete    

Stress-strain relationship of recycled self-compacting concrete filled steel tubular column subjected

Feng YU, Cheng QIN, Shilong WANG, Junjie JIANG, Yuan FANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 760-772 doi: 10.1007/s11709-020-0618-3

摘要: As a typical compression member, the concrete-filled steel tube has been widely used in civil engineering structures. However, little research on recycled self-compacting concrete filled circular steel tubular (RSCCFCST) columns subjected to eccentric load was reported. In this study, 21 specimens were designed and experimental studies on the stress-strain relationship of were carried out to study the mechanical behaviors. Recycled coarse aggregate replacement ratio, concrete strength grade, length to diameter ratio and eccentric distance of specimens were considered as the main experimental parameters to carry out eccentric compression tests. The corresponding stress-strain relationship curves were used to analyze the influence of concerned parameters on eccentric load-bearing capacity of RSCCFCST columns. The experimental results show that the strain of the eccentric compression stress-strain curves increase with the increase of recycled coarse aggregate replacement ratio and concrete strength grade. With increase of eccentric distance, the ductility of specimens increases while the bearing capacity decreases. Moreover, a phenomenological model of RSCCFCST columns is proposed, which exhibits versatile ability to capture the process during loading. The present study is expected to further understanding the behaviors and to provide guidance of RSCCFCST columns in design and engineering applications.

关键词: concrete filled circular steel tubular columns     recycled self-compacting concrete     eccentric compression     recycled coarse aggregate replacement ratio     stress-strain relationship    

Causality relationship between the photovoltaic market and its manufacturing in China, Germany, the US

Molin HUO, Xiliang ZHANG, Jiankun HE

《能源前沿(英文)》 2011年 第5卷 第1期   页码 43-48 doi: 10.1007/s11708-010-0135-5

摘要: This paper aims to investigate the Granger causality relationships between the photovoltaic (PV) market scale and PV manufacturing development in China, Germany, the US, and Japan, and consequently provide recommendations for strategic investment and industrial policy making. The empirical results show that the growth of the market scale caused the increase in innovation scale in the four countries except China. Moreover, there were bidirectional causalities between them in Germany and in the US, respectively, suggesting that the strategic perspective and the formation of a virtuous circle could make PV industry policies cost effective. Only in China did the growth of the market scale cause the increase in production scale, implying significant market risk for the manufacturing sector. The empirical result shows that the manufacturing sector can affect the dynamics of the market scale.

关键词: photovoltaic     innovation     demand pull     scale economies     granger causality    

toolbox for molecular property prediction based on quantum mechanics and quantitative structure-property relationship

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 152-167 doi: 10.1007/s11705-021-2060-z

摘要: Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemical-based products. The life cycles of chemical products involve the procedures of conceptual product designs, experimental investigations, sustainable manufactures through appropriate chemical processes and waste disposals. During these periods, one of the most important keys is the molecular property prediction models associating molecular structures with product properties. In this paper, a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions, such as activity coefficient, and so forth. The workflow of framework consists of three steps. In the first step, a database is created for collections of basic molecular information; in the second step, quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties (pseudo experimental data), which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step. The whole framework has been carried out within a molecular property prediction toolbox. Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.

关键词: molecular property     quantum mechanics     quantitative structure-property relationship     heat of reaction     solid-liquid phase equilibrium    

论GIS空间关系描述中存在的几个基本问题

邓敏,李成名,刘晓丽

《中国工程科学》 2013年 第15卷 第5期   页码 20-24

摘要:

首先剖析了空间关系描述中“空间”的概念,论述了拓扑关系具有与实体位置本身无关的特性,进而阐述了空间实体的拓扑表达,分析了拓扑空间描述存在的不足,以及与地理环境、地理空间认知的相关性,提出了纳入度量特性的拓扑空间关系描述的方法。

关键词: 空间     拓扑空间关系     空间关系描述    

The change of serum leptin and its relationship with platelet membrane glycoprotein Ib in patients with

XIA Dasheng, SONG Yanqiu, LI Chao, ZHANG Feng, WEI Minxin

《医学前沿(英文)》 2007年 第1卷 第4期   页码 352-355 doi: 10.1007/s11684-007-0067-6

摘要: The aim of this paper was to investigate the change of serum leptin and its relationship with platelet membrane glycoprotein Ib (GP Ib) in patients with coronary heart disease (CHD). The enrolled included 50 patients with CHD (CHD group) and 30 patients without CHD (control group) who were diagnosed by coronary angiography. The positive percentage and the average fluorescence intensity of platelet membrane GP Ib were detected by full-blood flow cytometry. Serum leptin was detected by enzyme linked immunosorbent assay. The positive percentage and the average fluorescence intensity of platelet membrane GP Ib in the CHD group were significantly lower than those in the control group (<0.05). After correcting the differences of systolic blood pressure, body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting glucose, PPBS, fasting insulin and quantitative insulin sensitive index, serum leptin level in the CHD group was significantly higher than that in the control group (<0.05). Single factor correlative analysis revealed that serum leptin in CHD patients was negatively correlated with the average fluorescence intensity of platelet membrane GP Ib (<0.05). Multifactorial stepwise regression analysis showed that serum leptin in CHD patients was independently negatively correlated with the average fluorescence intensity of platelet membrane GP Ib (<0.05). Logistic analysis demonstrated that serum leptin was independently correlated with the risk of CHD (<0.05). Hyperleptinemia was verified in CHD patients. The increase of serum leptin could affect blood platelet activation. Hyperleptinemia may play an important role in the pathogenesis of CHD.

Effect of arsenic trioxide on proliferation and apoptosis of U266 cells and its relationship with the

ZHAN Rong, YU Qinghong, HUANG Haobo

《医学前沿(英文)》 2008年 第2卷 第4期   页码 356-360 doi: 10.1007/s11684-008-0068-0

摘要: The aim of this article is to explore the effect of arsenic trioxide (AsO) on the proliferation and apoptosis of myeloma cell line U266 and its relationship with the expression variation of vascular endothelial growth factor (VEGF). The viability and apoptosis of U266 cells were observed by methylthiazolyl- tetrazolium (MTT) assay and terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL). The effect of AsO on the VEGF expression of U266 cells were tested by enzyme linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) analysis. We found that AsO could significantly inhibit the growth of U266 cells, and the concentration for 50% growth inhibition (IC) was 2 ?mol/L. After treatment with 2, 5, 10 ?mol/L AsO for 36 hours, dose-dependent apoptosis of U266 cells was observed. After treatment with 2, 5, 10 ?mol/L AsO for 72 hours, a dose-dependent reduction of VEGF in the supernatant of U266 cells culture was found. As far as single cells are concerned, nevertheless, the expression of VEGF mRNA did not vary. So we draw the conclusion that AsO could induce the apoptosis of U266 cells and inhibit their proliferation, decrease the tumor load, and lead to the reduction of VEGF in the culture supernatant, but not change the expression of VEGF in single U266 cells.

关键词: VEGF expression     expression variation     culture supernatant     labeling     concentration    

Moment-curvature relationship of FRP-concrete-steel double-skin tubular members

Mingxue LIU, Jiaru QIAN

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 25-31 doi: 10.1007/s11709-009-0012-7

摘要: Tests were conducted on 3 specimens to study the flexural behavior of fiber reinforced polymer (FRP)-concrete-steel double-skin tubular members (DSTMs). The strip method was used to calculate the section moment-curvature curves of the 3 specimens and 12 models. A theoretical formula is presented for the flexural strength of DSTMs. The test results show that the tension zone of the specimen FRP tubes was in hoop compression while the compression zone was in hoop tension. The load-carrying capacity did not decrease even when the mid-span deflection reached about 1/24 of the span length. The tests, simulation and theoretical analysis resulted in a simplified formula for the flexural strength of DSTMs and a tri-linear moment-curvature model was expressed as a function of the section bending stiffness for DSTMs.

关键词: fiber reinforced polymer (FRP)     concrete     steel     double-skin tubular members (DSTMs)     moment-curvature curve     flexural strength    

标题 作者 时间 类型 操作

Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

Mapping the structure-activity relationship of

Worawan PANPIPAT, Hasene KESKIN, Zheng GUO

期刊论文

Property-performance relationship of core-shell structured black TiO photocatalyst for environmental

期刊论文

Stress-strain relationship with soil structural parameter of collapse loess

SHAO Shengjun, YU Qinggao, LONG Jiyong

期刊论文

Stress-strain relationship with soil structural parameters of collapse loess

SHAO Shengjun, LONG Jiyong, YU Qinggao

期刊论文

Relationship between expression of hepatocyte grow factor and apoptosis of trophoblasts in hypertensive

OUYANG Shan, ZHANG Qinghua, QIAO Fuyuan

期刊论文

Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

期刊论文

Stress-strain relationship of recycled self-compacting concrete filled steel tubular column subjected

Feng YU, Cheng QIN, Shilong WANG, Junjie JIANG, Yuan FANG

期刊论文

Causality relationship between the photovoltaic market and its manufacturing in China, Germany, the US

Molin HUO, Xiliang ZHANG, Jiankun HE

期刊论文

toolbox for molecular property prediction based on quantum mechanics and quantitative structure-property relationship

期刊论文

论GIS空间关系描述中存在的几个基本问题

邓敏,李成名,刘晓丽

期刊论文

The change of serum leptin and its relationship with platelet membrane glycoprotein Ib in patients with

XIA Dasheng, SONG Yanqiu, LI Chao, ZHANG Feng, WEI Minxin

期刊论文

Effect of arsenic trioxide on proliferation and apoptosis of U266 cells and its relationship with the

ZHAN Rong, YU Qinghong, HUANG Haobo

期刊论文

Moment-curvature relationship of FRP-concrete-steel double-skin tubular members

Mingxue LIU, Jiaru QIAN

期刊论文