Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization （SSH） library were constructed from the roots of salt-sensitive Yul...Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization （SSH） library were constructed from the roots of salt-sensitive Yulu cultivar melon seedlings under salt stress; 557 high-quality expressed sequence tags （ESTs） were randomly sequenced, with an average size of 428 bp, which assembled into 68 contigs and 315 singletons. Compared with our previous SSH library generated from the salt-tolerant Bingxuecui cultivar, the proportion of transcripts involved in metabolism, protein fate, cellular communication/signal transduction mechanisms, and cell rescue/defense were 4, 1.46, 0.94, and 0.4% higher, respectively, in the salt-tolerant cultivar than the in salt-sensitive cultivar. Quantitative real-time PCR analysis of eleven transcripts revealed temporal variations in their expression in the two cultivars under salt stress. One NAC gene （JZ477011） was heterologously expressed in yeast for functional characterization, and enhanced the sensitivity of yeast cells to high-salinity to salt stress and inhibited their growth. Information regards to their functions would aid in the understanding of response mechanisms to saline stress and in the development of molecular markers for selecting salt-tolerant melon cultivars.展开更多
The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method ...The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method is the cornerstone of analytical formula,and then introduced into linear adjustment theory;the least square least norm solution,the optimized initial pre-stress,is yielded.The initial pre-stress and structural performances of a particular single-layer saddle-shaped cable-net structure were analyzed with the developed method,which is proved to be efficient and correct.The modal analyses were performed with respect to various pre-stress levels.Finally,the structural performances were investigated comprehensively.展开更多
Chronic stress can induce hippocampus injury such as neuron loss and dendrite atrophy,but its mechanism and molecular basis remain unclear up to now.To understand the molecular mechanism on protein level and find the ...Chronic stress can induce hippocampus injury such as neuron loss and dendrite atrophy,but its mechanism and molecular basis remain unclear up to now.To understand the molecular mechanism on protein level and find the crucial proteins which correlated with chronic展开更多
The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented here...The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome.展开更多
Subsea wellhead connector is the key equipment for offshore oil and gas production. The working water depth is generally more than 500 m, so it has higher requirements for its sealing performance. In this paper, the V...Subsea wellhead connector is the key equipment for offshore oil and gas production. The working water depth is generally more than 500 m, so it has higher requirements for its sealing performance. In this paper, the VX gasket matched with H-4 subsea wellhead connector is taken as the research object, and the mechanical analysis under preload and production conditions is carried out. The finite element model of subsea wellhead connector is established by ABAQUS software, and the influence of axial preload, production pressure and material properties on the sealing performance of VX gasket is studied. The results show that the greater the axial preload, the greater the contact stress on the gasket surface;the contact stress decreases first and then increases linearly with the increase of production pressure;the material properties of the gasket are also an important factor affecting its sealing performance, 316L stainless steel is more suitable for gasket material than 304 stainless steel and Inconel625.展开更多
The performance of underground excavations is inevitably influenced by rock mass characteristics, presence of joints and their geometrical properties, depth below surface and state of in-situ stress field. The objecti...The performance of underground excavations is inevitably influenced by rock mass characteristics, presence of joints and their geometrical properties, depth below surface and state of in-situ stress field. The objective of this paper is to investigate the behaviour of deep underground tunnel opening existed between two bedding planes, Such planes weaken the strength of rock mass and may cause rock slippage/rotation along them. Therefore, the state of stress-displacement, after tunnel opening has been introduced, is examined using two-dimensional elasto-plastic finite-elements code, RS^(2D). The results indicate that, there is significant drop in the normal stress along joints over tunnel opening; slip occurs due to reversal in the direction of shear stress(e.g., inward shear displacement is produced) and there is discontinuity in the strength contours of rock surrounding tunnel after they have been intersected by bedding planes.展开更多
Borehole breakout is a widely utilised phenomenon in horizontal stress orientation determination,and breakout geometrical parameters,such as width and depth,have been used to estimate both horizontal stress magnitudes...Borehole breakout is a widely utilised phenomenon in horizontal stress orientation determination,and breakout geometrical parameters,such as width and depth,have been used to estimate both horizontal stress magnitudes.However,the accuracy of minimum horizontal stress estimation from borehole breakout remains relatively low in comparison to maximum horizontal stress estimation.This paper aims to compare and improve the minimum horizontal stress estimation via a number of machine learning(ML)regression techniques,including parametric and non-parametric models,which have rarely been explored.ML models were trained based on 79 laboratory data from published literature and validated against 23 field data.A systematic bias was observed in the prediction for the validation dataset whenever the horizontal stress value exceeded the maximum value in the training data.Nevertheless,the pattern was captured,and the removal of systematic bias showed that the artificial neural network is capable of predicting the minimum horizontal stress with an average error rate of 10.16%and a root mean square error of 3.87 MPa when compared to actual values obtained through conventional in-situ measurement techniques.This is a meaningful improvement considering the importance of in-situ stress knowledge for underground operations and the availability of borehole breakout data.展开更多
为分析热防护材料领域研究现状和未来发展趋势,文章采用信息可视化、网络分析的研究方法,以Web of Science(WOS)数据库及中国知网(CNKI)数据库中近30年(1993年1月—2023年6月)热防护材料相关的文献作为数据来源绘制可视化信息图谱,对发...为分析热防护材料领域研究现状和未来发展趋势,文章采用信息可视化、网络分析的研究方法,以Web of Science(WOS)数据库及中国知网(CNKI)数据库中近30年(1993年1月—2023年6月)热防护材料相关的文献作为数据来源绘制可视化信息图谱,对发文量、发文国家地区和机构、研究方向、核心作者、关键词等元素逐一进行分析,剖析热防护材料研究领域的发展动态、研究热点及前沿趋势。结果显示,美国、中国为主要研究国家,在该领域居重要地位;LI J(Li Jun)、SONG G W(Song Guowen)、SU Y(Su Yun)、LU Y H(Lu Yehu)、王云仪、朱方龙等作者为该领域的核心作者,在热应激、热防护服的研究中具有重要影响力;热防护服的热防护性与传热机制、人体的热生理与热舒适为活跃的研究主题与研究热点;相变材料、气凝胶、形状记忆织物、蜂窝夹芯织物、三维间隔织物为当前的研究热点材料,新型热防护材料的研发、服装内部结构的优化是未来研究中有效应对热应激的解决方法,是兼顾热防护服的热防护与热舒适平衡的重要途径。展开更多
基金supported by grants from the National Natural Science Foundation of China(31372079)the National High Technology Research and Development Program of China(863 Program,2012AA101903)+1 种基金the Natural Science Foundation of Shanghai Science and Technology Committee,China(13ZR1422400)Shanghi Graduate Education and Innovation Program(Horticulture),China
文摘Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization （SSH） library were constructed from the roots of salt-sensitive Yulu cultivar melon seedlings under salt stress; 557 high-quality expressed sequence tags （ESTs） were randomly sequenced, with an average size of 428 bp, which assembled into 68 contigs and 315 singletons. Compared with our previous SSH library generated from the salt-tolerant Bingxuecui cultivar, the proportion of transcripts involved in metabolism, protein fate, cellular communication/signal transduction mechanisms, and cell rescue/defense were 4, 1.46, 0.94, and 0.4% higher, respectively, in the salt-tolerant cultivar than the in salt-sensitive cultivar. Quantitative real-time PCR analysis of eleven transcripts revealed temporal variations in their expression in the two cultivars under salt stress. One NAC gene （JZ477011） was heterologously expressed in yeast for functional characterization, and enhanced the sensitivity of yeast cells to high-salinity to salt stress and inhibited their growth. Information regards to their functions would aid in the understanding of response mechanisms to saline stress and in the development of molecular markers for selecting salt-tolerant melon cultivars.
文摘The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method is the cornerstone of analytical formula,and then introduced into linear adjustment theory;the least square least norm solution,the optimized initial pre-stress,is yielded.The initial pre-stress and structural performances of a particular single-layer saddle-shaped cable-net structure were analyzed with the developed method,which is proved to be efficient and correct.The modal analyses were performed with respect to various pre-stress levels.Finally,the structural performances were investigated comprehensively.
文摘Chronic stress can induce hippocampus injury such as neuron loss and dendrite atrophy,but its mechanism and molecular basis remain unclear up to now.To understand the molecular mechanism on protein level and find the crucial proteins which correlated with chronic
基金Project (No.863-705-210) supported by the Hi-Tech Research and Development Program (863) of China
文摘The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome.
文摘Subsea wellhead connector is the key equipment for offshore oil and gas production. The working water depth is generally more than 500 m, so it has higher requirements for its sealing performance. In this paper, the VX gasket matched with H-4 subsea wellhead connector is taken as the research object, and the mechanical analysis under preload and production conditions is carried out. The finite element model of subsea wellhead connector is established by ABAQUS software, and the influence of axial preload, production pressure and material properties on the sealing performance of VX gasket is studied. The results show that the greater the axial preload, the greater the contact stress on the gasket surface;the contact stress decreases first and then increases linearly with the increase of production pressure;the material properties of the gasket are also an important factor affecting its sealing performance, 316L stainless steel is more suitable for gasket material than 304 stainless steel and Inconel625.
文摘The performance of underground excavations is inevitably influenced by rock mass characteristics, presence of joints and their geometrical properties, depth below surface and state of in-situ stress field. The objective of this paper is to investigate the behaviour of deep underground tunnel opening existed between two bedding planes, Such planes weaken the strength of rock mass and may cause rock slippage/rotation along them. Therefore, the state of stress-displacement, after tunnel opening has been introduced, is examined using two-dimensional elasto-plastic finite-elements code, RS^(2D). The results indicate that, there is significant drop in the normal stress along joints over tunnel opening; slip occurs due to reversal in the direction of shear stress(e.g., inward shear displacement is produced) and there is discontinuity in the strength contours of rock surrounding tunnel after they have been intersected by bedding planes.
基金The work reported here is funded by Australian Coal Industry’s Research Program(ACARP)(No.C26063).
文摘Borehole breakout is a widely utilised phenomenon in horizontal stress orientation determination,and breakout geometrical parameters,such as width and depth,have been used to estimate both horizontal stress magnitudes.However,the accuracy of minimum horizontal stress estimation from borehole breakout remains relatively low in comparison to maximum horizontal stress estimation.This paper aims to compare and improve the minimum horizontal stress estimation via a number of machine learning(ML)regression techniques,including parametric and non-parametric models,which have rarely been explored.ML models were trained based on 79 laboratory data from published literature and validated against 23 field data.A systematic bias was observed in the prediction for the validation dataset whenever the horizontal stress value exceeded the maximum value in the training data.Nevertheless,the pattern was captured,and the removal of systematic bias showed that the artificial neural network is capable of predicting the minimum horizontal stress with an average error rate of 10.16%and a root mean square error of 3.87 MPa when compared to actual values obtained through conventional in-situ measurement techniques.This is a meaningful improvement considering the importance of in-situ stress knowledge for underground operations and the availability of borehole breakout data.
文摘为分析热防护材料领域研究现状和未来发展趋势,文章采用信息可视化、网络分析的研究方法,以Web of Science(WOS)数据库及中国知网(CNKI)数据库中近30年(1993年1月—2023年6月)热防护材料相关的文献作为数据来源绘制可视化信息图谱,对发文量、发文国家地区和机构、研究方向、核心作者、关键词等元素逐一进行分析,剖析热防护材料研究领域的发展动态、研究热点及前沿趋势。结果显示,美国、中国为主要研究国家,在该领域居重要地位;LI J(Li Jun)、SONG G W(Song Guowen)、SU Y(Su Yun)、LU Y H(Lu Yehu)、王云仪、朱方龙等作者为该领域的核心作者,在热应激、热防护服的研究中具有重要影响力;热防护服的热防护性与传热机制、人体的热生理与热舒适为活跃的研究主题与研究热点;相变材料、气凝胶、形状记忆织物、蜂窝夹芯织物、三维间隔织物为当前的研究热点材料,新型热防护材料的研发、服装内部结构的优化是未来研究中有效应对热应激的解决方法,是兼顾热防护服的热防护与热舒适平衡的重要途径。
