对流

Existence of critical convective heat transfer coefficient h c shows that for naturally cooled monobloc barrel, large h and small δ is selected when strength and manufacturing processes are considered simultaneously.

临界对流传热系数hc的存在表明，对自然散热条件下单筒身管来说，在重量、刚度允许条件下，增加壁厚可以达到降低内膛温度的目的；就主动冷却身管而言，选择大h、小δ时需兼顾强度和制造工艺性。

For naturally cooled monobloc barrel, its thermal condition in regular regime can be evaluated by measuring the outside temperature of two arbitrary rounds;(2) During a sustained firing process, unsteady heat conduction exists in a monobloc barrel, whereas unsteady and quasi steady heat conduction exist with actively cooled composite barrels, meaning that the thermal condition changes from uncontrolled to controlled;(3) Different combinations of the convective heat transfer coefficient h and thickness of gun barrel δ have much effects on cooling the bore temperature.

利用有限元软件分析了某大口径火炮身管的温度场分布，并对自然散热条件下的单筒身管和主动冷却条件下的复合身管温度场进行了比较，其结果为(1)身管温度场分布存在初始和正规工况阶段，后者的单筒身管热状态可以通过测定任意两发身管外表面温度来评估；(2)持续射击过程中，单筒身管始终处于非稳态导热过程，主动冷却身管则包括非稳态和准稳态两个过程，实现了身管热状态由不可控向可控转变；(3)对流传热系数h和身管壁厚δ的组合对降低内膛温度具有很大影响。

In the summer, south-westerly monsoonal winds reach northern India, in an explosion of heat-busting rain, in late June.

夏天，西南季风影响北印度并在六月底带来充沛的对流降雨。

Kalamaili suture zone is an important plate boundary in north Xinjiang, and there are plenty of Neopaleozoic volcanic rocks around itThese volcanic rocks are enriched in LILEs and relatively depleted in HFSEs, and they are also characterized by high Nb, Zr, TiO2 contents and Zr/Y, Nb/Y ratios, and depleted SrNd isotopesThe characteristics of these volcanic rocks suggest that they were produced in postcollisional periodThe postcollisional volcanic rocks around Kalamaili suture zone become younger from west to east, which indicates that this suture zone entered postcollisional period gradually from west to east, and reflects that the Kalamaili Ocean had been closed gradually from west to eastAs to the Kalamaili suture zone in postcollisional period, the lithosphere extended and thinned, and the asthenosphere materials upwelled and melted partially, and intensive mantle convection occurred, leading to a plenty of mantlederived magmas underplating the suture zoneThe lithospheric mantle metasomatized by fluid in subduction period melted partially under decompression and high temperature, the resulting melts contaminated the underplating asthenospheric materials, and the erupted lavas became the Neopaleozoic postcollisional volcanic rocks

卡拉麦里缝合带是北疆的一条重要界线，沿该带广泛发育晚古生代火山岩。这些火山岩具有LILE相对富集、HFSE相对亏损的特征，且具有较高的Nb、Zr、TiO2含量和Zr/Y、Nb/Y比值，SrNd同位素主要表现出亏损的特征。综合分析表明，这些火山岩形成于后碰撞期。对卡拉麦里缝合带而言，从西向东后碰撞火山岩的时代逐渐变新，表明该缝合带从西向东逐渐演化进入后碰撞期，这从侧面反映了卡拉麦里洋盆是从西向东逐渐关闭的。对卡拉麦里缝合带而言，在后碰撞期，岩石圈伸展减薄，软流圈地幔物质上涌并发生部分熔融，加上地幔对流作用强烈，使得缝合带下产生了大规模的幔源岩浆底垫；先前在洋壳消减期被流体交代提取过的岩石圈地幔也在低压高温下发生部分熔融，形成的熔体混染了底垫的软流圈物质并喷发，形成了晚古生代的后碰撞期火山岩。

The steam side heat exchange is a forced convective film condensation process of the flowing vapor, containing noncondensable gases. The flow filed and heat transfer behavior vary sharply along the cooling surface.

汽侧的凝结换热是存在不凝结空气的汽气混合物的强迫对流膜状凝结换热，流动与传热特性沿冷却表面变化剧烈。

The model of CFB boiler components such as gas-solid separator, external heat exchanger, nonmechanical valves and heat transfer surfaces are considered in the overall model.

依据循环流化床锅炉各部件包括分离器、返料机构、外置式换热器及对流受热面的运行特点，对这些部件的模型也进行了讨论并给出。

Numerical simulation and study of the orographic effect of Dabie Mountains on the mesoscale convective system of a spring cold front .

大别山区地形对春季冷锋附近中尺度对流系统影响的数值模拟研究。

The results will be improved if terrain coordinate is used and orographic effects are considered when simulating convective processes over mountainous or hill areas.

所以在模拟山区和丘陵地带的对流系统时，采用地形坐标并考虑地形将会改善模式的模拟结果。

Through assuming the same character of continuum and smooth at dimensionless coagulation rate when Péclet number as the independent variable, the analytical results of the three perturbational orders of weak Brownian motion on the strong gravitational motion are gained.

再给以纯Brown碰并率无量纲化的碰并率对于极值点对应的Péclet数有同样连续光滑的性质，求得中Péclet数条件下，重力对流与Brown运动都不能看成小量的耦合碰并条件下，粒子的碰并率；并同时得到高Péclet数条件下碰并率的后三阶解析解。

The saturation equals 1 in saturated region.The piezometric tube waterhead equals position head by neglecting the effect of capillarity in unsaturated region.So the nonlinear parabolic equation of seepage flow will degenerate to Laplace equation about piezometric tube waterhead in saturated region and convective equation about saturation in unsaturated region respectively.

将渗流域分为饱和区与非饱和区，为避免研究复杂的多相流问题，可以认为非饱和区是与大气相通的，则测压管水头中的压力与大气压相等，使测压管水头等于位置水头，从而渗流控制方程在两个区域中分别退化为关于测压管水头的拉普拉斯方程和关于饱和度的对流方程。

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％。