水面散热的焓差公式及其应用

我国现在所用的水面散热公式，包括蒸发散热、对流散热、辐射散热三部分，以此为基础建立的计算蒸发系数的通用公式是有缺陷的，其中不应包含水气温差。因为水气温差是对流散热的推动力，而蒸发散热只传质，不传热，只产生汽化潜热，所以不应有对流散热的成分。产生上述问题的原因是在实验中蒸发散热和对流散热是不可分的，本文将蒸发散热和对流散热合为一个公式，提出用焓差公式来整理试验资料，给出了以焓差为推动力的散热公式，使原有计算公式得到简化,更符合实际。     

Development of a laser wavefront sensor for measurement of discharges in air

A laser wavefront sensor of the Shack‐Hartmann type capable of simultaneous measurement at two wavelengths was constructed. The sensor uses a single optical path, and is suited for applications such as high‐voltage discharges in air, in which large insulation distances are necessary. The sensor was used to detect optical path differences due to an impulse discharge in air across a needle–plane electrode gap of gap length 17 mm. Optical path differences were measured at laser wavelengths of 532 and 1064 nm at 1.6 µs after insulation breakdown across the gap. From the difference in optical path differences at the two wavelengths, a line‐integrated electron density distribution in the direction perpendicular to the gap was obtained near the high‐voltage electrode. The distribution had a peak value of 1.4 × 10²⁰m^?2 and a full width at half maximum of 4.4 mm. Because of the coverage of a large observation area including the entire gap, the spatial resolution was 1.4 mm, which was inadequate to obtain the precise form of the electron density distribution. However, the results show the possibility of applying laser wavefront sensing to electron density measurement. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 10–17, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10247     

Gender-Typed Play and Amniotic Testosterone.

Sex differences in play are apparent in a number of mammalian species, including humans. Prenatal testosterone may contribute to these differences. The authors report the first attempt to correlate gender-typed play in a normative sample of humans with measurements of amniotic testosterone (aT). Testosterone was measured in the amniotic fluid of 53 children (31 boys and 22 girls). A strong sex difference was observed in aT and, at ages 4.75 to 5.8 years, on a modified version of the Child Game Participation Questionnaire. Hierarchical regression analyses on the entire group and within-sex correlations suggested that variations in aT did not contribute to individual differences in game participation as reported by the mother. A critique of explanations for this finding is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FDTD方法及其在多注电子光学系统研究中的应用

采用时域有限差分(FDTD)方法对L波段100 kW多注速调管的单个电子枪进行三维模拟计算,通过设置最小网格尺寸和发射时间间隔,得出的电流和导流系数与采用EGUN等软件计算的结果相一致,通过从MAFIA中导入三维磁场数据,模拟了位于径向不同位置处电子注通道的电子轨迹,研究发现在磁场均匀性较好的情况下,位于径向不同位置处的电子轨迹相差很小,同时讨论了如何减少模拟时间的问题.本文最后计算了多个注的电子枪,求得了电流值和导流系数,从中导入数据可以分段模拟多注速调管高频互作用段的注波互作用,以及收集极区域的电子发散.     

Concentration polarisation in tubular membranes —a numerical approach

A theoretical investigation ofparticle deposition onto a permeable surface of a tubular membrane is presented. Themass transport mechanisms are mathematically expressed using the two-dimensional convective diffusion equation. A numerical scheme is presented to solve the two-dimensional convective diffusion equation at the steady state for the case of nonuniform permeation velocity. This equation is solved numerically using a finite difference method. The numerical prediction of mass transfer in the mass boundary requires the use of a very dense grid. The concentration profiles along the membrane surface and the mass boundary layer are predicted. The effect of the Reynolds number, the wall Reynolds number and the Schmidt number were investigated. Correlations for the concentration boundary layer thickness δ_c/D=2(z/D)^0.33(ReSc)^{− 0.33} Re_w^−0.3 (1-0.4377 Sc^−0.0018 Re_w^−0.1551), and for the Sherwood number Sh =1.230 [(D/z) ReSc] ^0.33 (1 + 0.010 Re^−0.125Sc^1.055 Re_w.^1.132) based on the predicted values of the solute concentration profiles, are proposed, in the operating condition ranges 300 < Re < 1000, 0.02 < Re_w < 0.3 and 600 < Sc < 3200.     

层状介质时移时差属性分析

针对我国油藏特征主要是薄层和薄互层，而且大多采用水驱开采，叠后时移时差属性较弱．难以识别。为此，就影响层状介质中叠前时移时差属性的各种因素进行了系统分析。设计了一个双层水平层状模型，探讨了叠前时移时差随炮检距的变化规律以及地层结构(储层厚度，储层速度，储层埋深，上覆地层速度等)对叠前时差的影响。结果表明，当储层埋深较浅，且上覆地层速度低于储层速度时，只要储层厚度以及速度的变化足够大．利用叠前大炮检距时移时差来揭示储层动态变化是可能的；对于埋深很大、上覆地层速度接近或高于储层速度的情形，叠前时移时差往往很小，实用性较差。     

Stability of partial difference equations governing control gains in infinite-dimensional backstepping

We examine the stability properties of a class of LTV difference equations on an infinite-dimensional state space that arise in backstepping designs for parabolic PDEs. The nominal system matrix of the difference equation has a special structure: all of its powers have entries that are −1, 0, or 1, and all of the eigenvalues of the matrix are on the unit circle. The difference equation is driven by initial conditions, additive forcing, and a system matrix perturbation, all of which depend on problem data (for example, viscosity and reactivity in the case of a reaction–diffusion equation), and all of which go to zero as the discretization step in the backstepping design goes to zero. All of these observations, combined with the fact that the equation evolves only in a number of steps equal to the dimension of its state space, combined with the discrete Gronwall inequality, establish that the difference equation has bounded solutions. This, in turn, guarantees the existence of a state-feedback gain kernel in the backstepping control law. With this approach we greatly expand, relative to our previous results, the class of parabolic PDEs to which backstepping is applicable.     

半参数模型误差为鞅差序列的r阶矩相合性

利用偏残差法并综合最小二乘法,给出了半参数回归模型中参数β和非参数g(t)的、(t),在误差为鞅差序列时,得到了、(t)的r(r≥2)阶矩相合性.     

Break Expectancy in Duration Discrimination.

Effects of break expectancy, observed previously in time production, were examined in 3 experiments using a discrimination paradigm. Participants classified a tone as being short or long. Location and duration of breaks in tone presentation were varied. Proportion of short responses increased as the break occurred later in the duration to be estimated in all experiments. With a higher number of break locations covering a wider range of location values, functions relating proportion of short responses to location were sigmoid and tended to flatten at extreme values of location. The authors conclude that attentional time-sharing elicited by break expectancy induces loss in accumulation of temporal information, but its effect on discrimination depends on the accumulation outcome relative to a decisional criterion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

裂缝预测主曲率法的新探索

构造面主曲率在一定程度上控制了裂缝发育的密度、方向、宽度和深度；因而油层厚度及与之有关的裂缝孔隙体积和渗透率也在一定程度上受到构造面主曲率的影响。由微分几何学原理得到计算主曲率的一般公式，克服了由薄板小扰度弯曲理论得到的主曲率计算公式的局限性。使用趋势面分析与差分法相结合的方法，处理离散的构造层面数据，计算构造面主曲率，选取各点主方向上两个主曲率值中绝对值较大者作为裂缝发育区预测的依据。在江汉盆地王场地区用该方法预测的裂缝发育区与实际基本一致。图5参12