条斑紫菜酵母双杂交文库的构建及PyMAPK5互作蛋白的筛选     

董道英  孔凡娜  崔正彩  孙斌 《海洋与湖沼》2019,50(6):1271-1280

为进一步研究条斑紫菜促分裂原活化激酶家族PyMAPK5的下游互作蛋白,理解其生物学功能,本研究通过酵母双杂交的方法进行其相互作用蛋白的筛选。提取不同温度和失水逆境胁迫下的RNA,利用Invitrogen体系构建条斑紫菜酵母双杂交cDNA文库,其库容为1.44×107CFU,重组率为91.8%。以pGBKT7-PyMAPK5为诱饵蛋白载体,利用共转化方法,从文库中筛选得到26个与PyMAPK5互作的候选蛋白。候选蛋白集中在光系统II相关蛋白、捕光蛋白、微管蛋白、ATP酶、GTP结合蛋白及假设蛋白等。微管蛋白、捕光蛋白、光系统II蛋白一对一验证结果为阳性,表明在酵母体内存在互作。本研究为阐明条斑紫菜PyMAPK5与其互作蛋白的关系及解析PyMAPK5下游作用机制奠定了基础。  相似文献   

级配碎石填料大三轴试验及累积塑性应变预测模型     

杨志浩  岳祖润  冯怀平  叶朝良  马德良 《岩土力学》2020,41(9):2993-3002

级配碎石作为重载铁路基床表层的主要填料，其受列车荷载的影响最大。因此，研究级配碎石在循环荷载作用下的动力行为及累积塑性应变演化特征变得尤为重要。首先，通过制备不同细粒含量的级配碎石填料，开展一系列大型动三轴试验，探究细粒含量、围压及动应力幅值对循环荷载作用下试样累积塑性应变的耦合影响机制。其次，基于塑性安定理论，确定不同应力水平下试样的动力行为，得到考虑围压及细粒含量参数的塑性蠕变状态临界动应力计算模型。最后，结合试验数据，建立考虑应力水平及细粒含量参数的塑性蠕变动力行为累积塑性应变预测模型，并明确各参数的物理意义。其研究成果可为既有重载铁路路基健康状态评估及考虑强度、变形综合控制的路基结构设计提供参考。  相似文献   

塔河油田奥陶系储层构造应力场研究     

刘佳庚  李静  苏玉亮  范作松  刘旭亮  郭豪 《地质力学学报》2020,26(1):48-54

油气储层构造应力场的分布特征，对油气运移、注采井网布置、储层改造等具有重要意义。为此，文章从塔河油田AD13井区的地质构造演化入手，基于油田测井资料，结合弹性力学及有限元理论，建立研究区地应力弹性力学计算模型，利用有限元软件对研究区储层地应力进行模拟研究，并将模拟结果与现场地应力实测值进行对比分析。结果表明，研究区最大水平主应力为102~130 MPa，最小水平主应力为87~110 MPa，均为压应力；研究区东部及南部最大水平主应力方向为北东向，西北部最大水平主应力方向为北东东向，西南部最大水平主应力方向为南东向，地应力大小及方向均与实际结果相符。研究结果可为研究区油气勘探开发工程提供科学依据。   相似文献   

Three dimensional numerical simulation of residential building on shrink–swell soils in response to climatic conditions          下载免费PDF全文

Xiong Zhang  Jean‐Louis Briaud 《国际地质力学数值与分析法杂志》2015,39(13):1369-1409

Shrink–swell soils can cause distresses in buildings, and every year, the economic loss associated with this problem is huge. This paper presents a comprehensive system for simulating the soil–foundation–building system and its response to daily weather conditions. Weather data include rainfall, solar radiation, air temperature, relative humidity, and wind speed, all of which are readily available from a local weather station or the Internet. These data are used to determine simulation flux boundary conditions. Different methods are proposed to simulate different boundary conditions: bare soil, trees, and vegetation. A coupled hydro‐mechanical stress analysis is used to simulate the volume change of shrink–swell soils due to both mechanical stress and water content variations. Coupled hydro‐mechanical stress‐jointed elements are used to simulate the interaction between the soil and the slab, and general shell elements are used to simulate structural behavior. All the models are combined into one finite element program to predict the entire system's behavior. This paper first described the theory for the simulations. A site in Arlington, Texas, is then selected to demonstrate the application of the proposed system. Simulation results are shown, and a comparison between measured and predicted movements for four footings in Arlington, Texas, over a 2‐year period is presented. Finally, a three‐dimensional simulation is made for a virtual residential building on shrink–swell soils to identify the influence of various factors. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Implicit integration under mixed controls of a breakage model for unsaturated crushable soils          下载免费PDF全文

Yida Zhang  Giuseppe Buscarnera 《国际地质力学数值与分析法杂志》2016,40(6):887-918

This paper discusses a series of stress point algorithms for a breakage model for unsaturated granular soils. Such model is characterized by highly nonlinear coupling terms introduced by breakage‐dependent hydro‐mechanical energy potentials. To integrate accurately and efficiently its constitutive equations, specific algorithms have been formulated using a backward Euler scheme. In particular, because implementation and verification of unsaturated soil models often require the use of mixed controls, the incorporation of various hydro‐mechanical conditions has been tackled. First, it is shown that the degree of saturation can be replaced with suction in the constitutive equations through a partial Legendre transformation of the energy potentials, thus changing the thermomechanical state variables and enabling a straightforward implementation of a different control mode. Then, to accommodate more complex control scenarios without redefining the energy potentials, a hybrid strategy has been used, combining the return mapping scheme with linearized constraints. It is shown that this linearization strategy guarantees similar levels of accuracy compared with a conventional strain–suction‐controlled implicit integration. In addition, it is shown that the use of linearized constraints offers the possibility to use the same framework to integrate a variety of control conditions (e.g., net stress and/or water‐content control). The convergence profiles indicate that both schemes preserve the advantages of implicit integration, that is, asymptotic quadratic convergence and unconditional stability. Finally, the performance of the two implicit schemes has been compared with that of an explicit algorithm with automatic sub‐stepping and error control, showing that for the selected breakage model, implicit integration leads to a significant reduction of the computational cost. Such features support the use of the proposed hybrid scheme also in other modeling contexts, especially when strongly nonlinear models have to be implemented and/or validated by using non‐standard hydro‐mechanical control conditions. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Fracture mechanics analysis of multiple cracks in anisotropic media     

Chia‐Huei Tu  C.‐S. Chen  T.‐T. Yu 《国际地质力学数值与分析法杂志》2011,35(11):1226-1242

This paper presents a single‐domain boundary element method (BEM) for linear elastic fracture mechanics analysis in the two‐dimensional anisotropic material. In this formulation, the displacement integral equation is collocated on the un‐cracked boundary only, and the traction integral equation is collocated on one side of the crack surface only. A special crack‐tip element was introduced to capture exactly the crack‐tip behavior. A computer program with the FORTRAN language has been developed to effectively calculate the stress intensity factors of an anisotropic material. This BEM program has been verified having a good accuracy with the previous researches. Furthermore, by analyzing the different anisotropic degree cracks in a finite plate, we found that the stress intensity factors of crack tips had apparent influence by the geometry forms of cracks and media with different anisotropic degrees. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

The effective stress concept and the evaluation of changes in pore air pressure under jacketed isotropic compression tests for dry sand based on the 2‐phase porous theory          下载免费PDF全文

Sayuri Kimoto  Fusao Oka  Yasuhiro Morimoto 《国际地质力学数值与分析法杂志》2017,41(18):1894-1907

The effective stress concept for solid‐fluid 2‐phase media was revisited in this work. In particular, the effects of the compressibility of both the pore fluid and the soil particles were studied under 3 different conditions, i.e., undrained, drained, and unjacketed conditions based on a Biot‐type theory for 2‐phase porous media. It was confirmed that Terzaghi effective stress holds at the moment when soil grains are assumed to be incompressible and when the compressibility of the pore fluid is small enough compared to that of the soil skeleton. Then, isotropic compression tests for dry sand under undrained conditions were conducted within the triaxial apparatus in which the changes in the pore air pressure could be measured. The ratio of the increment in the cell pressure to the increment in the pore air pressure, m, corresponds to the inverse of the B value by Bishop and was obtained during the step loading of the cell pressure. In addition, the m values were evaluated by comparing them with theoretically obtained values based on the solid‐fluid 2‐phase mixture theory. The experimental m values were close to the theoretical values, as they were in the range of approximately 40 to 185, depending on the cell pressure. Finally, it was found that the soil material with a highly compressible pore fluid, such as air, must be analyzed with the multi‐phase porous mixture theory. However, Terzaghi effective stress is practically applicable when the compressibilities of both the soil particles and the pore fluid are small enough compared to that of the soil skeleton.  相似文献   

Application of the numerical manifold method for stress wave propagation across rock masses     

G. F. Zhao  X. B. Zhao  J. B. Zhu 《国际地质力学数值与分析法杂志》2014,38(1):92-110

In this paper, the numerical manifold method (NMM) is extended to study wave propagation across rock masses. First, improvements to the system equations, contact treatment, and boundary conditions of the NMM are performed, where new system equations are derived based on the Newmark assumption of the space–time relationship, the edge‐to‐edge contact treatment is further developed for the NMM to handle stress wave propagation across discontinuities, and the viscous non‐reflection boundary condition is derived based on the energy minimisation principle. After the modification, numerical comparisons between the original and improved NMM are presented. The results show that the original system equations result in artificial numerical damping, which can be overcome by the Newmark system equations. Meanwhile, the original contact scheme suffers some calculation problems when modelling stress wave propagation across a discontinuity, which can be solved by the proposed edge‐to‐edge contact scheme. Subsequently, the influence of the mesh size and time step on the improved NMM for stress wave propagation is studied. Finally, 2D wave propagation is modelled, and the model's results are in good agreement with the analytical solution. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

A 3D discrete FEM iterative algorithm for solving the water pipe cooling problems of massive concrete structures          下载免费PDF全文

Jing Cheng  T. C. Li  Xiaoqing Liu  L. H. Zhao 《国际地质力学数值与分析法杂志》2016,40(4):487-508

Water pipe cooling has been widely used for the temperature control and crack prevention of massive concrete structures such as high dams. Because both under‐cooling and over‐cooling may reduce the efficiency of crack prevention, or even lead to great harm to structures, we need an accurate and robust numerical tool for the prediction of cooling effect. Here, a 3D discrete FEM Iterative Algorithm is introduced, which can simulate the concrete temperature gradient near the pipes, as well as the water temperature rising along the pipes. On the basis of the heat balance between water and concrete, the whole temperature field of the problem can be computed exactly within a few iteration steps. Providing the pipe meshing tool for building the FE model, this algorithm can take account of the water pipe distribution, the variation of water flow, water temperature, and other factors, while the traditional equivalent algorithm based on semi‐theoretical solutions can only solve problems with constant water flow and water temperature. The validation and convergence are proved by comparing the simulated results and analytical solutions of two standard second‐stage cooling problems. Then, a practical concrete block with different cooling schemes is analyzed and the influences of cooling factors are investigated. In the end, detailed guidance for pipe system optimization is provided. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Modeling 3D thermal fracture propagation by transient cooling using virtual multidimensional internal bonds          下载免费PDF全文

K. Huang  A. Ghassemi 《国际地质力学数值与分析法杂志》2016,40(17):2293-2311

Thermal fracturing can play an important role in development of unconventional petroleum and geothermal resources. Thermal fractures can result from the nonlinear deformation of the rock in response to thermal stress related to cold water injection as well as heating. Before the rock reaches the final failure stage, material softening and bulk modulus degradation can cause changes in the thermo‐mechanical properties of the solid. In order to capture this aspect of the rock fracture, a virtual multidimensional internal bond‐based thermo‐mechanical model is derived to track elastic, softening, and the failure stages of the rock in response to the temporal changes of its temperature field. The variations in thermo‐mechanical properties of the rock are derived from a nonlinear constitutive model. To represent the thermo‐mechanical behavior of pre‐existing fractures, the element partition method is employed. Using the model, numerical simulation of 3D thermal fracture propagation in brittle rock is carried out. Results of numerical simulations provide evidence of model verification and illustrate nonlinear thermal response and fracture development in rock under uniform cooling. In addition, fracture coalescence in a cluster of fractures under thermal stress is illustrated, and the process of thermal fracturing from a wellbore is captured. Results underscore the importance of thermal stress in reservoir stimulation and show the effectiveness of the model to predict 3D thermal fracturing. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献