Age of acquisition: Its neural and computational mechanisms.

The acquisition of new skills over a life span is a remarkable human ability. This ability, however, is constrained by age of acquisition (AoA); that is, the age at which learning occurs significantly affects the outcome. This is most clearly reflected in domains such as language, music, and athletics. This article provides a perspective on the neural and computational mechanisms underlying AoA in language acquisition. The authors show how AoA modulates both monolingual lexical processing and bilingual language acquisition. They consider the conditions under which syntactic processing and semantic processing may be differentially sensitive to AoA effects in second-language acquisition. The authors conclude that AoA effects are pervasive and that the neural and computational mechanisms underlying learning and sensorimotor integration provide a general account of these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

水力压裂净压力拟合分析解释技术研究与应用

基于三维裂缝延伸模拟模型的水力压裂净压力拟合分析解释技术,提出了净压力拟合分析解释的一般步骤及理论方法,研究了现场监测净压力的计算方法,并介绍了其在现场施工中的应用情况。该技术可以帮助认识地层参数和压裂参数,提高压裂施工成功率和有效率。     

CDMA系统中联合功率控制、波束赋形与多用户检测

应用功率控制、波束赋形和多用户检测可以有效地消除和减少CDMA系统中的干扰。本文结合波束赋形和多用户检测的特性，提出一种应用波束赋形增益和多用户相关矩阵的解相关算法。基于算法的复杂性，提出一种区分聚集用户进行多用户检测的的算法。由于波束赋形能够消减主瓣波束之外的多用户干扰，对聚集移动台采用解相关检测达到减少运算量和消除多用户干扰的目的。对算法进行了仿真分析，证明了本算法的优越性。     

A direct numerical simulation of transition phenomena in a mixed convection channel flow

This study intends to provide an increased understanding of the laminar-turbulent transition phenomena for the buoyancy-assisted heated vertical channel flow during the early transient stage. The spectral method with weak formulation is applied in the direct numerical simulation. Initial disturbances consist of the finite-amplitude two-dimensional TS wave and a pair of three-dimensional oblique waves for the K-type disturbances. The results from the harmonic energy competitions of different wave modes show that for the buoyancy-assisted heated flow, the (k_x=1, k_z=1) or (1,1) and (1,0) modes would gain energy immediately and start to rise at almost the same rate. This phenomenon is different from that of the buoyancy-opposed flow, where the (1,1) mode decays slowly in the beginning until other modes gain enough energy and then it begins to grow quickly and overtakes the (1,0) mode after a short time period. These different transition patterns match with the experimental results that the flow transition is supercritical and subcritical for the buoyancy-assisted and -opposed flows, respectively. Buoyancy-assisted heated flow transition follows the general trend of an isothermal flow in the beginning, but the thermal-buoyant force is crucial in accelerating the instability and also causing notable differences during the subsequent transition process. All of the results for the vortex structures development, kinetic energy budget of the disturbances, flow visualization by tagged fluid particles, and the local temperature fluctuations are consistent in pointing to a clear pattern for the buoyancy-assisted heated flow transition.     

核电站中椭圆柱形屏蔽体辐射衰减率的仿真研究

为了预测核电站中椭圆柱形屏蔽体的辐射衰减率，该文用数值解析法对放射线源到评价点的放射线所穿透椭圆柱形屏蔽物体的交点进行了研究。首先用空间解析法建立了椭圆柱形物体的数学模型。然后解曲面方程求出交点。在判断放射线是否穿透此椭圆柱体时，该文又提出了椭圆柱形屏蔽体的假想外接长方体的建模方法，将曲面方程联立解的复杂计算简化为一次代数方程的简单计算，大幅度地缩短了计算时间。     

不同锌钛比对纳米钛酸锌（ZnO—TiO2）体系成分的影响

以工业偏钛酸、硫酸锌、氨水为主要原料，用直接沉淀法并进行热处理得到钛酸锌粉体，并用XRD对产物成分进行了检测。结果表明，不同的锌钛比对钛酸锌（ZnO-TiO2）体系的成分有较大影响。     

Web服务在信用信息工程中的应用

目前的社会信用信息工程中,许多的政府部门都建立了自己的信用信息数据库,但在政府各级部门数据库之间进行数据交流和共享存在着许多的问题,在许多地方,数据共享还是一片空白。Web服务技术是应用程序通过内联网或者因特网发布和利用软件服务的一种标准机制。利用WEB服务可以方便地实现不同系统之间的数据交换和集成。该文提出利用web服务技术来解决信用信息工程中的信息数据共享问题。并在此基础上提出利用WEB服务工作流技术将信用评估整合到电子商务过程,以实现可信用电子商务     

Generation of gas bubbles in microflow using micropipette with ultrasound

Ultrasound was applied to a micropipette micromixer to improve dispersion of gas and liquid in a microchannel. Flow visualization using a high-speed camera was performed to examine the effect of ultrasonic irradiation on bubble generation in the microchannel. Basically, nitrogen gas was injected using a (0.5 µm ID) glass micropipette into ethanol flowing in a rectangular (100 µm×200 µm) microchannel on polydimethylsiloxane (PDMS). Gas and liquid flow rates were regulated using mass flow controllers. At aflow condition that is typical of bubbly flow, ultrasound was transmitted into the microchannel using a piezo-electric (PZT) transducer over a range of operating voltages (2 to 200 Vp-p) and frequencies (50 to 60 kHz). Images captured during the action of the PZT transducer indicate that bubble formation is influenced by ultrasound. When subjected to ultrasound above 50 Vp-p and at the resonant frequency of the PZT transducer, bubbles formed that were smaller and closer together, signifying enhanced shearing of the gas at the micropipette tip by the liquid. The observation of gas slugs occurring sooner might be attributed to the coalescence of gas bubbles that became closely spaced.     

基于T0944的新型平板显示接口卡的设计

介绍了平板显示控制芯片TO944的特点、功能、原理，并给出了基于T0944芯片的新型平板显示接口卡的软硬件实现方案，该方案具有电路简单、高可靠性、高性价比、高显示质量等优点，可用于各种不同类型与不同尺寸的平板显示器的显示。     

用φ76 mm穿孔机组生产φ63mm毛管的设备改进

介绍了用Φ76mm穿孔机组生产Φ63mm毛管的设备概况及其改进。改进后，Φ76mm穿孔机组增加了产品范围为后面的冷技工序减少了拉拔道次，从而降低了Φ51mm以下冷拔管的生产成本。