Blood vessels in the head tighten to stop the loss of body heat and then relax to let blood flow rise; that sudden rush of blood is what causes the headache.
头部的血管收紧以阻止身体热量的流失，然后放松让血液流动起来，血液的突然涌入是引起头痛的原因。
Waving can mean welcome and farewell, whereas scratching your head may indicate that you are at a loss.
挥手表示欢迎和告别，而挠头则表示不知所措。
The financial rescue plan passed by the US Congress is viewed as flawed but necessary to head off panic in financial markets and loss of confidence in the economy.
人们认为美国国会通过的金融纾困计划有缺陷，但对于防止金融市场中出现恐慌情绪、避免人们丧失对经济的信心，又是必要之举。
The sherry went to my head and I was im- poverished for days by the loss of sixpence.
六便士的酒钱落到我头上，接下来几天我几乎身无分文。 这里的女主人叫艾伦?
Two years ago, his elderly mother began showing signs of memory loss after striking her head on the pavement outside her home.
2年前，年岁已高的妈妈在门口的人行道上摔到了头，之后开始出现失忆症状。
Using a mirror, check your head for hair loss.
照一下镜子，看下你的头上有没有掉头发。
Concussions are a type of internal head injury that causes the temporary loss of normal brain function.
脑震荡是一种闭合性脑损伤，它会引起短暂的脑功能障碍。
To see expert solutions to gum disease and learn how to head off disease and tooth loss, check out how to Manage gum disease.
可点击如何防止牙周病来看看专家的意见，学习如何防止牙齿脱落和口腔疾病。
The full round port area provides maximum flow capacity and minimum head loss.
完全的圆形流道截面能够提供最大的流量和最小的流压损失。
The Newton iteration method is used to solve the economic pressure on the unknown node, so as to calculate the economic head loss and economic pipe diameter of each section,.
采用牛顿迭代法来求解各未知节点的经济水压，进而得出各管段的经济水头损失、经济管径和水源二级泵站的经济扬程。
The valve is an impeding part with larger pressure head loss and a lot of discharge energy consumed.
风量调节阀系阻性部件，存在较大的压头损失，须消耗大量送风能量。
Influential factors of friction factor of head loss are analyzed by adopting artificial neural network (ANN).
采用神经网络(ANN)方法对沿程水头损失系数的影响因素进行了分析。
The backwater and general formula of the local head loss of regulation structures is presented in this paper.
简述整治建筑物的壅水及其机理，归纳出局部水头损失壅水的通用公式。
This paper deals with the basic demands for designing filter tube and the head loss occurring when groundwater enters into the filter from aquifer.
论述了滤水管设计的基本要求和地下水由含水层进入滤水管时的水头损失。
It is shown that the relationship exists among the location of the flaring gate piers, the Froude number at the section of starting flare, the weir head, the head loss and the gate width.
研究了宽尾墩位置、始扩点水流佛汝德数与堰上水头之间的关系，导出了与水头损失、闸门宽度有关的计算公式。
This paper presents a nonuniform slap door, whose top hinge refrains from impact when the door is opened and the head loss of the water is zero when the door running steady.
本文提出一种新的非均质拍门，可使拍门在启门时顶铰免受冲力，在稳定运行时拍门水头损失为零。
The calculation of local head loss in a pressured curved tube is very important for the design of the construction of inverted siphon.
有压弯管局部水头损失计算在倒虹吸等过水建筑物设计中至关重要。
Ulteriorly, considering the local head loss in inlet opening and pipes junction plays more important role in the calculative results of water hammer pressure calculation of the short pipeline system.
考虑进口及多管道连接处的局部水头损失对短管道系统水击压强的计算结果影响较大。
Usually the cost of printing ink, head loss, by the media, and some film. The figure of waste composition.
通常喷绘的本钱由喷头损耗、墨水、介质、废图和覆膜挂轴等有些构成。
The computation for the processing head loss of water diversion in the pressure pipe is related to that whether or not the project can reach the designed flowrate or the project can operate safely.
有压管道输水的沿程水头损失计算，关系到工程能否达到设计输水流量和能否安全运行。
It is an effective method for improving test precision that the water head loss tests of hydropower station inlet section are performed by increasing discharge or raising reservoir water level.
同时采用加大流量法和提高库水位进行进水口段的水力损失试验，对提高试验精度是一个行之有效的方法。
In order to make optimal operation calculation of small hydroplant more accurate and rational, head loss of hydroelectric plant with complex diversion system is analyzed in this paper.
为了使小型水电站厂内优化运行计算的结果更趋准确、合理，对具有复杂引水系统的小型水电站引水损失情况进行了分析。
The main purpose of the experimental study on the water fow in the transition region of an aqueduct is to find out the local coefficient of head loss in the region.
渡槽渐变段水力学试验的基本目的，是测定渐变段的局部水头损失系数。
The major problems in this technology are PAC penetrating filter material layer and the great shorten of the filter cycle owing to the growth rate of filter head loss is so quickly.
该投加点面临的主要问题是活性炭穿透滤料层以及水头损失过快增长导致滤池过滤周期的大幅度缩短。
However, For pipes with local resistance loss, the friction head loss caused by the viscosity of fluid does exist, which may lead to the calculation error.
但是在形成局部阻力损失的管段中，还会同时伴随产生由于液体的粘性力引起的漩程水头损失，这就造成了这项损失的计算误差。
Chiu and Seman (1971) studied the head loss of flows transporting sediment in circular and square pipes with spiraling motion.
邱和思门(1971)研究了在圆管和方形管中输沙时具有螺旋运动的水流的水头损失问题。
As a porous support device has larger opening percentage, the filtering head loss can be greatly reduced.
由于本实用新型的多孔支撑装置开孔率很大，可大大减小过滤水头损失。
Its shortcomings include harsh restriction for suspended solid in influent, low phosphorus removal efficiency, high water-head loss and the height of lifting sewage.
但同时也存在对进水悬浮物要求较高，磷去除率低，水头损失大，污水提升高度大等问题。
When the flow ratio of diffluent and conflux increases, the head loss I...
分流情况下的水头损失比汇流情况下的水头损失要大。
The head loss of flume is less, and the average loss is nearly 12% of the total head in upstream.
机翼形量水槽的水头损失较小，平均水头损失约占上游总水头的12%左右。
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