压下

NBTI effects can also be influenced by ratio of signal and vacancy. The dynamic characteristics in NBTI degradation was revealed under action of negative and positive gate voltage, degradation can be recovered by positive gate voltage stress.

在负-正-负栅压交替作用下PMOSFET器件中会呈现退化-钝化-退化的动态作用过程，正栅压作用下的PMOSFET器件特性退化会有一定程度的恢复，这是由于在正栅压作用下NBTI反应产物逆向向Si／SiO〓界面处运动从而发生钝化作用造成的。

In this investigation, the compression behavior of COx argillite with two different grain size distributions, which were obtained by two different crush procedures, was studied by running 1D compression tests with several loading-unloading cycles.

通过开展一维压缩试验，研究2种不同粉碎工艺下获得的粗／细COx土样的压缩特性，结果表明：压缩曲线受粒度成分的影响非常明显，为获得同等压实度，细粒土所需的压实功能较粗粒土高，除此之外，细粒土的压缩指数也高于粗粒土，表现出较强的压缩性；随着土样压实密度的增加，粗／细土样的压缩曲线逐渐靠拢，粒度成分对压实功能影响逐渐减弱；土样卸荷时回弹指数随干密度的增加而增加，受粒度成分的影响不明显；高压实ρ(下标 d=2.0g/立方公分粗粒土样在7 MPa的轴向应力下饱和时，体积发生明显的塌陷现象，饱和后土样的压缩指数小于饱和前，而回弹指数则较饱和前高。

Experiments of flow conductivity closure stress of typical propping agent are done, propping agent short-term flow conductivity alteration index is defined, by this, the relation between fissure short-term flow conductivity and closure stress, it is close to exponential relation. 4. Establishing the mathematical simulator of hydraulic fractured well's production in a steady state, finding the relation curve between dimensionless flow conductivity and fracture penetration coefficient by means of calculation and analyses, it is the basis of hydraulic fracture. 5. Expatiating the importance of optimized hydraulic fracturing design in reservoir engineering, advancing the optimizing design method, fracture dimension can be calculated easily when the physical parameters are known. 6. Production rate decline standard curve of vertical fractured wells is achieved by mathematical simulation, when the flow pressure is certain , by asymptotic analyze, this decline curve is close to exponential relation.

完成了国内外典型支撑剂的导流能力闭合应力影响实验，在数据分析中定义了支撑剂短期导流能力变异系数，并由此发现裂缝短期导流能力随闭合应力变化的近似符合指数关系式； 4 建立了一种水力压裂井稳态产能的数学模拟器，计算分析找到了最优无量纲导流能力与裂缝穿透比之间的新型关系曲线，它是水力压裂优化设计的基础； 5 阐述了水力压裂油藏工程优化设计的重要性，提出了优化设计方法，在已知支撑剂物性参数条件下可简洁计算最优裂缝尺寸； 6 数学模拟给出了垂直裂缝井产量递减标准曲线，在井底定压条件下通过渐近分析表明，该递减曲线满足指数关系式。

In accordance with the business card printing and membership card making the box below, shall be provided with rubber gaskets, grid and made into the middle of a slightly higher than the chloroben-the shape of a drum, and the next box tops with 8 but for supporting compression spring, so as to be able to make natural rubber gasket following the lead of the glass plate burning, the framework is equipped with light fixtures for compact disk, in the box below.

不梢据制卡和会员卡制息工艺请求，下框务必撤有网格型橡胶衬垫，并且制成角落稍矮于显鼓的轮廓，下框台不活下有8只压簧息支承，从而不妨使橡胶衬垫板滞不松贴着晒版的玻璃，框架撤有笨重的压不松安设，专不求压不松上、下框之用。

Therefore it is necessary to research the mechanism of greensand used for high compacted molding methods thoroughly.This subject is one section of the National Natural Science Foundation subject ""Ivestigation on Predicting Method and Mechanism of Springback for High Compacted Sand Molds"", followed of the other completed one named ""Research on Microdeformation of Molding Sand"". A serious of experiments has been done on the reequipped three axial machine under certain technological conditions, and the mechanics, material science, rheologic science. It is systematically studied that the influences on the springback of sand mold were caused by the main influence factors: pressure, compacted rate and the content of soil. Through the analyzed experiments' data, the experienced stress-strain relationship concerning the main influence factors were obtained;under different technical parameter, the springback and spingback's potential energy are compared, the differences and indifferences between them are found out, and the springback's mechanism is discussed;according to the tests' data of YangGuoping coming from Tinghua University, experienced formula of molding sand's springback displacement is induced, the displacement and springback are compared, the margin of error's reasons are analyzed, and they are tested and verified mutually.

本课题为国家自然科学基金项目"高紧实度砂型预测方法及回弹机理的探讨"的一部分，是已结题的国家自然科学基金项目"铸造型砂微变形的研究"的后继，运用力学、材料学及流变学理论，利用改装的三轴仪，在一定的工艺条件下，作了大量系列实验，系统的研究了压实比压、紧实率和膨润土含量对砂型回弹的影响；对实验数据进行了分析和处理，得出了型砂关于压实比压、紧实率和膨润土含量的本构关系的经验公式；把各工艺参数下的型砂产生的回弹量与回弹势能进行比较，找出两者存在的异同点，并对回弹机理进行了探讨；通过清华大学杨国平的实验数据，推导出型砂回弹位移场的经验公式，并与实验测出的回弹量进行比较，分析误差造成的原因，并互相进行了验证。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

In Scramjet, the evaporation of most liquid fuel occurs under the subnormal pressure condition. However, it is rarely seen in the existing documents about the study of the evaporation and combustion of the fuel droplet at subnormal pressure. This thesis gives the experimental and theoretical study about that.

在超燃冲压发动机的燃烧室中，液体燃料的蒸发大部分是在一个负压环境下完成的，现有文献对负压环境下燃料液滴蒸发和燃烧过程的研究却很少，本文对负压环境下燃料液滴蒸发过程进行了试验和理论研究。

The reliability of analysis result depends largely on the in-house experimental conditions. Unlike the previous analysis that only concerns the sole effect of permeable pressure, this article considers both permeable and confining pressure and deformation characteristics of concrete material under the interaction of them according to the real work state of construction, which may leads to the changing pattern of permeable rate as listed below: permeable rate always reaches its peak with the time process going on, than goes down and remains straight on some certain value; The PR will tend to decline while the confining pressure is increased, and the time taken before the peak will be extended as well; Under the constant permeable pressure and circularly changing confining pressure, the minus-exponential ascend and descend relationship could be applied between the PR and Time axes respectively with crannied and intact concrete samples, and the PR of crannied concrete is far more larger than that of intact concrete. The change pattern of concrete could also be mathematically analogized using the least square method.

室内的实验条件是研究成果可靠性的重要因素，而以往的研究都只考虑了渗透压单一作用，本文根据混凝土结构的实际工作状态，同时考虑了围压与渗透压共同作用下的混凝土材料的渗透性变化特征，得出了混凝土材料在围压作用与渗透压共同作用下的渗透率的变化规律：渗透率都是随时间推移先达到一个峰值，再降低并趋于平稳；渗透率会随围压的增大而减小，并且峰值的到达时间也会随之延长；在渗透压不变，围压升降循环的情况下，有裂缝、无裂缝混凝土的渗透率变化规律是随时间成负指数关系上升、下降，且有裂缝混凝土试件的渗透率远远高于无裂缝混凝土的渗透率，并对混凝土的变化规律运用最小二乘法进行数学拟合。

By Ensemble-averaged Method, the mean field was got to show the 3D structure of flow. By Phase-locked Averaged Technique, the periodic mean field was got to reflect the periodic unsteady characteristic. The 3D structure and the periodic unsteady characteristic of the unsteady flow within the vaneless and vaned diffuser were discussed through analyzing the mean field and the periodic mean field.

离心风机扩压器内非定常流动的实验研究本文完成了离心风机两种结构条件下无叶扩压器、有叶扩压器内部的非定常流动瞬态全流场的实验测量，获得了不同运行工况下PIV的瞬态流谱，为研究扩压器内部非定常流动提供了基础实验资料。

The shear layer vortices dominate in the initial portion of the jet, which are a result of the K-H instability. The crossflow encounters an adverse pressure gradient ahead of the jet and separates to form horseshoe vortices under the pressure downstream, and they develop into the wake. The wake vorticity comes into being in the actions of an adverse pressure gradient and a wall-normal component of vorticity, which originates from the wall boundary and is entrained into the jet. The shear layer vortices encounter adverse pressure gradients in the lee of the jet and break down, leading to the formation of the CVP and the CVP is the most important characteristic of the jet in crossflow.

文中指出：剪切层涡源于射流与横流之间的K-H不稳定性；马蹄形涡的产生是由于射流喷口上游迎风侧的壁面边界层内存在逆压梯度，使流动发生了分离，在下游逆压梯度的挤压作用下，形成了马蹄形涡，马蹄形涡向下游发展，进入尾迹区；在逆压梯度和法向涡生成项的共同作用下产生了尾迹涡，尾迹涡源于壁面边界层，止于射流，并将部分涡量向上输运至射流内部的CVP；CVP是横向紊动射流的重要特征，剪切层涡破裂后，在逆压梯度的作用下CVP形成。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。