不可逆性

The main factors affecting the soil-structure interface behaviors were found experimentally and theoretically, including: 1 the thickness of the interface that is five to six times the average grain size of the soil; 2 the aeolotropy of interface, which is responsible for anisotropic response of the stress-strain response of the interface; 3 two physical states, including crashing and compression of the soil near the structure surface, which govern the stress-strain response of the interface strongly; 4 two shear deformation components due to sliding and constraint of the structure surface relative to the soil respectively, which forms the deformation of the interface; 5 the volumetric strain due to dilatancy, which is found to be composed of a reversible dilatancy component and an irreversible dilatancy component. 4. A unified constitutive model of the interface, based on new elasto-plasticity damage theory, was developed. It was confirmed to be effective for the conditions considering monotonic and cyclic shearing, coupling effect of shear and volumetric strains, evolution of physical state, micro-structure aeolotropy of the soil and the resulting aeolotropy of the interface as well as the three normal boundary conditions stated above. 5. 2D and 3D finite element formulations of the present model were derived and incorporated into the FEM codes. They were applied to the evaluation of practical engineering problems with different typical interfaces between soil and structure. The new model was shown to be reasonable and effective.

确定了粗粒土与结构接触面厚度约为5～6倍的平均粒径，首次揭示了接触面的细观结构异向性以及由此所引起的宏观剪切异向性，发现了在单调和往返剪切荷载作用下土颗粒破碎和剪切压密两种物态变化机制共同支配着接触面力学性质的变化，通过细观分析证实了接触面的变形可分解为一般同时发生的土与结构交界面上的滑移变形以及结构面位移约束范围之内土体本身的剪切变形两部分，观测到接触面受剪时表现出明显的相对法向位移，并可分解为可逆性和不可逆性两个分量；(4)建立了第一个能够统一地描述单调与往返剪切特性、剪应变与体应变耦合特性、细观结构和宏观剪切异向性以及土颗粒破碎等物态变化特性的土与结构接触面弹塑性损伤本构数学模型，并采用多种法向边界条件复杂加载路径的试验成果验证了新模型的合理性和有效性；(5)提出了新模型的二、三维有限元格式并结合实际边值问题进行了应用计算分析，比较了不同接触面本构模型对计算结果的影响，证实了新模型及其有限元格式不仅能够合理地描述土与结构接触面的主要力学特性，还能够较好地反映土体与结构物在接触面处的滑移、脱开等不连续现象。

By using the Jordan decomposition of the generator, the difference in terms of the autocorrelation function between the reversibility and the irreversibility is shown.

使用生成元的若当分解，给出了以自相关函数描述的可逆性和不可逆性之间的区别。

The main results of the investigation are as following:(1) Some important criteria for the design of multi-layer structure are acquired: the ratio of the layer thickness to the contact diameter should be controlled to a value about 0.8; increasing the number of the gradient layers and elasticity modulus of the top layer would benefit to the yield strength and the stress status at the interface.（2）By means of molecular dynamics simulations for a indentation and sliding process, it is discovered that dislocations of 45 direction to the surface occur in the surfaces layer, which is correspond to the direction of the plastic flows observed in the macroscopic continuous medium. The irreversible deformation caused by the dislocation and the atom piles at the surface are responsible for the irreversibility of the force response. They are also the main factors for the friction generation. The temperature and the indentation velocity have significant effects on the deformation behaviors of the material of the surface layer. The yield strength would increase obviously if the indentation velocity is greater than 10 m/s.（3）A method to evaluate the fracture toughness of coating by estimating the crack-density functionβof a Wicker''s indentation was proposed. Meanwhile a new surface treatment technology was developed using non-equilibrium plasma.（4）A MD-FE hybrid method and corresponding software was developed to analysis the tribological behaviors for multiplayer system.

研究主要内容和结果有：（1）得到指导梯度膜设计的几个准则：控制膜层厚度与接触半径比在0.8左右为宜；适当增加梯度层层数和顶层弹性模量，有利于提高抗屈服能力和改善界面处的应力状态；（2）通过对嵌入和滑动摩擦过程的分子动力学模拟，发现表层产生一个与宏观连续介质的塑性流动方向观测一致的45 方向位错；位错造成的不可逆变形和表面的原子堆积，是力的响应不可逆性的原因，也是构成摩擦力的主要因素；温度和嵌入速度对材料变形特性有显著的影响，当嵌入速度大于10 m/s时，屈服强度明显增加；（3）提出压痕裂纹密度系数β半定量判定膜层断裂韧性的方法；并开发出表面强化新工艺；（4）开发出分析表面摩擦学特性的MD-FE复合模拟方法和相应模拟软件。

In addition, the mass transfer process of main components in the heat pump cycle, such as a generator and an absorber, is analyzed, and the mass trasfer model, the relation of its separation effectiveness with the thermodynamic inconvertibility are described.

根据热力学第一、二定律，从理论上建立了描述该类热泵的数学模型。从热力学不可逆性原理出发，分析了热泵循环过程的热力学不可逆性引起的〓损失。

The influence of high temperature and high pressure on foaming agent's properties in opened and closed system, and influence of the change of foaming agent's properties on foaming capacity and foam stabilizing capacity are also studied. The multiple regression theory is used to establish the quantitative characteristic functions of foaming agent versus temperature and pressure. Based on the Gibbs Principle, the quantitative characterization is carried out on relation of foam system's free energy versus its surface tension, surface area and concentration, and the analysis of energy concluded that the disintegration of the foam is inconvertible. At the same time, the influence of change of foam's shape and structure on distribution of reservoir temperature and pressure is qualitatively described, and the coupling mechanism between temperature field, pressure field and chemical field is systematically expounded.

同时，研究了不封闭体系、封闭体系下高温、高压对发泡剂性质的影响，以及发泡剂性质的改变对其发泡性能、稳泡性能的影响；采用泡沫实验的相关结果，运用多元回归理论，建立温度、压力与发泡剂浓度的定量表征函数；基于Gibbs原理，对高温、高压下泡沫体系的自由能与其表面张力、体系中液体的表面积以及浓度关系进行定量化的表征研究，从能量的角度得出了泡沫衰变过程具有不可逆性；同时定性地描述了泡沫形态、结构的变化对油藏温度和压力分布的影响，系统地阐述了温度场、压力场、化学场间的耦合作用机理。

The plastic deformation induced due to cyclic rotation of principal stress axes alone can be in the same magnitude as that due to shear with fixed principal stress axes. 2 The volumetric strain due to shearing of cyclic rotation of principal stress axes is found to be composed of a reversible dilatancy component and an irreversible dilatancy component. The former is characterized by its reversibility and is independent of past shear history, the latter by its irreversibility increases with the increase of cycle number yet its increase rate decreases with its accumulation. 3 The obvious non-coaxiality between directions of the principal stresses and principal strain increments is found and its degree depends largely on the change of shear stress component. 4 The intermediate principal stress has considerable effects on the deformation behavior of sands in the condition of cyclic rotation of principal stress axes. The accumulation rate of the irreversible dilatancy component increases with the increase of the intermediate principal stress parameter.

具有初始各向异性的砂土在纯应力主轴循环旋转排水条件下的主要变形规律为：①纯应力主轴循环旋转可产生与应力主轴固定单调剪切处于同一数量级的塑性变形；②纯应力主轴循环旋转引起的剪切体变包含可逆性剪切体变分量和不可逆性剪切体变分量两部分，其中可逆性剪切体变分量在一周内可完全恢复，基本与应力历史无关；不可逆性剪切体变分量随循环周数的增加呈单调增加，且增加速率随其自身累积值的增大呈减小趋势；③应变增量主轴与应力主轴之间的非共轴现象显著，且在一周内具有分段性；④中主应力对应力主轴循环旋转条件下砂土的变形特性有重要影响，不可逆性剪切体变分量的累积速率随中主应力系数的增加而增加。

Objective to explore the way of identify the size and evolving process of reversible damaged region and irreversible damaged region.

目的：对急性脑梗塞可逆性损伤区和不可逆性损伤区进行界定并观察其演变规律，为超急性期溶栓治疗的必要性及时间窗等问题提供影像学依据。

The major difference between these is reversibility or unreversibility of disease. If patients with acute renal failure are unable to get immediate and adequate medical care, they can progress to unreversible chronic renal failure, with a need for further dialysis or even transplantation.

肾衰竭分为急性和慢性肾衰竭，而两者最大的不同在於可逆与不可逆，然而急性肾衰竭病人若未能及时接受适当的治疗，将会演变为不可逆性的慢性肾衰竭，必要时将倚赖透析治疗或肾脏移植。

Bronchial mucosa cilia structure abnormality is common in acute stage of children with RRTI,but the majority of which were secondary cilia structure abnormality and adverted change,it is hope to recover after therapy,so we should make active anti-infection measure to treat children with RRTI while exploring cause to prevent unadverted change.

RRTI患儿急性期普遍存在着支气管黏膜纤毛上皮结构的异常，且多为继发性异常及可逆性损害，故对于RRTI患儿在查找病因的同时应积极进行抗炎对症治疗，防止纤毛结构异常发展为不可逆性的损害。

Bronchial mucosa cilia structure abnormality is common in acute stage of children with RRTI,but the majority of which were secondary cilia structure abnormality and adverted change,it is hope to recover after therapy,so we should make active anti-infection measure to treat children with RRTI while exploring cause to prevent unadverted change.

RRTI患儿急性期普遍存在着支气管黏膜纤毛上皮结构的异常，且为继发性异常及可逆性损害，故对于RRTI患儿在查找病因的同时应积极进行抗炎对症治疗，防止纤毛结构异常发展为不可逆性的损害。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。