流控制

A process for preparing superthin SiN film used as the protecting or dielectric layer of microelectronic or photoelectric material by electronic cyclone, resonance and microwave plasma technique is disclosed.

用电子回旋共振微波等离子体技术，适合于单晶Si衬底片，在一定微波功率条件下，通过调整(N2)/气体流速比，气压和生长时间控制薄膜厚度，在低温下生长超薄SiN薄膜。

The main research activities of the Department cover the general layout of hydro projects, hydraulics of spillways for high dams, energy dissipation and river bed or bank erosions, flow induced vibration, cavitation and air entrainment, river ice, hydraulic transient flow simulation and control on hydropower project, pumped storage project and long distance water transfer project, optimization of thermal/nuclear power plant and other industrial cooling systems, investigation of the fundamental theory of stratified/mixing flow and its applications, studies on fluid mechanics and thermodynamics of large scale cooling towers, hydraulic field observations for existing projects, development of instrumentation for physical model tests and field observations.

研究领域主要为水利水电枢纽总体布置、高坝泄洪建筑物水力学、消能防冲、流激振动、空化与空蚀、崩岸水力学与岸坡保护、河冰问题、水电站引水系统中的水力瞬变及调压井水力学研究、跨流域调水工程中的规划及水力控制数值仿真、冷却水的工程水力热力问题研究、环境水力学、火电厂水工模型试验与数值模拟研究、火电厂取排水局部泥沙冲淤试验、模型和原体监测仪器的研制和开发、以及过水现场原体监测。

The boost converter is a voltage step-up and current step-down converter .the current source is synthesized from a DC voltage source by adding a large value inductor in series .in DC regulated power supply applications ,the voltage sink represents a large value capacitor in parallel with the load resistance .in the application of the DC motor control ,the voltage sink represents the back emf of the DC motor .the switching action produces a pulsating current .the capacitive filter smoothens the pulsating current and provides a DC voltage to the load

升压转换器是一个升压和降流的转换器。电流源是一个直流电压源添加一个大值电感串联合成的。在直流稳压电源的应用，电压降代表一个大值电容并联一个负载电阻。在直流电机的控制应用中，电压降代表反电动势的直流电机。转换行为产生一个脉动电流。一个滤波电容是这个脉动电流平和并且提供直流的电压负荷。

They prescribe the optimum flow capacity locally or even temporally, and usually these changes are occurrences in the traffic.

由它们可以在不同的空间和时间点控制道路允许的最大流量，而这样一些变化实为交通流中普遍存在的现象。

The hydrogen solubility in Pd follows Sieverts law, and hydrogen diffusion through the bulk of the palladium membrane is the rate determining step. Whereas other gases only permeate through the pinholes or gaps in the Pd layer;the permeation can be quantitatively described as a combination of Knudsen diffusion and viscous flow.

氢气在钯膜中溶解渗透服从Sievert定律，并且氢的渗透扩散过程是速率控制步骤；而其他气体则通过膜中的针孔或裂隙进行扩散，其传质过程为Knudsen扩散和粘性流两种传递方式的综和。

For each strategy, a corresponding exploitation plan of groundwater was designed. Then each designed exploitation plan (except scheme 3) was put into the model for calculation and simulation. The analysis on the forecasting results every plan indicates that:(1) Shuting down the self-provided wells is the most direct and effective method, playing an important role in the land subsidence prevention.(2) The resumption of compressed soil by groundwater artificial recharge is limited. So the artificial recharge can\'t provide essential effect for the resumption of land subsidence, unless the artificial recharge is much more than the groundwater withdrawal.(3) The method of "adjusting the exploitation stratum of groundwater to the shallow" has an obvious effect on the land subsidence prevention.(4)"Sand wells" can increase the leakage recharge for confined aquifer, and thus can slow and prevent the development of the land subsidence.(5) For the groundwater exploitation in Xi\'an, emergency self-provided wells should be managed according to the well spacing of 1600m, 2000m and 1600m, respectively, in the river terrace area, alluvial-proluvial fan area and loess tableland area to exploit the first confined groundwater. Corresponding individual well yield can be set as 2500m~3/d, 1500 m~3/d and 200 m~3/d. Make emergency self-provided wells pump in the dry year and stop pumping groundwater to restore and conserve underground water sources in average years and wet years. In this way, groundwater withdrawal of 162000m~3/d can be obtained to provide for the supplement of water supply in Xi\'an. As a result, the water supply stress can be released in dry years. The groundwater depression formed in the exploiting year can resume in 3-4 years. At the same time, this exploitation manner will not lead to obvious land subsidence.

本文利用所建的模型预测了现状开采条件下未来20年的地下水位和地面沉降的变化，在此基础上，提出了防治西安市地面沉降的五个地下水开采方案，利用所建的地面沉降模型对各个设计方案其进行了模拟和预报，对预测结果的分析表明：①封停自备井是防治地面沉降最为直接和最有效的对策，对防治地面沉降起着最为积极的作用；②采用人工回灌方法使被压缩的土层得到的恢复是非常有限的，对地面沉降不能起到根治作用，只有回灌量明显大于开采量时才能有一定的效果；③&调整开采层次，在浅层取水&对防治地面沉降的效果十分明显；④布设&砂井&可以增加对承压含水层的越流补给量，从而可以有效地缓解和控制地面沉降的发生和发展；⑤对西安市的地下水开采，可在河流阶地区、冲洪积扇区和黄土塬区分别采用1600m、2000m、1600m的井间距布置应急自备井，分别采用2500m~3/d、1500 m~3/d和200 m~3/d的单井开采量，开采第一承压水，在平水年或者丰水年不开采，涵养地下水源，在枯水年启动这些应急自备井开采，在输出分析范围内共可获得162000 m~3/d(5913万m~3/a)开采量，可以有效地补充西安市的供水水源，缓解供水紧张局面，开采年开采导致的下降的水位可在停采3～4年后得到基本恢复，同时，这种开采方式不会造成大的地面沉降量。

In these experiments, it is managed to render the water entirely flowing into the rills to guarantee more accurate water flow dynamic condition.

试验中控制入流完全流入细沟中，能更准确地获得水流动力条件。

In the case of short - circuit,the output current amplitude and phase of PWM converter are controlled to adjust the equivalent impedance of current - limiter for fault current suppression.

故障发生后，通过变流器控制变压器二次侧注入电流的相位和幅值，进而调节限流器的等效阻抗，从而实现抑制短路电流的目的。

Based on the voltage pulse width modulation control strategy with single transistor chopped, the behavior patterns of chopping current and freewheeling current were analyzed under the single phase faults of power converter.

基于电压脉宽调制斩单管控制策略，分析变换器单相功率管故障情况下，斩波电流和续流电流的故障表现。

In addition, the activating unit has an element that extends through the mold unit to engage the valve pin, so as to control the molten plastic flow from a runner system to an injection chamber.

此外，致动单元具有一元件，它延伸通过模具单元以接合于阀销，以便控制熔化塑料流从一浇口系统到一注射腔室的流动。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。