过冷

The results show that 5% nucleating agent,twelve-hydrated disodium hydrogen phosphate,could reduce the supercooling degree of acetate hydroxide trihydrate to some extent but the supercooling degree was still large.However,the supercooling degree of sodium acetate trihydrate could decrease clearly by adding 3% thickener gelatin and 5% twelve-hydrated disodium hydrogen phosphate.

实验结果表明，质量百分比为5%的成核剂十二水磷酸氢二钠能一定程度上抑制无机水合盐三水醋酸钠的过冷度，但其过冷度仍然较大；使用质量百分比5%的十二水磷酸氢二钠和质量百分比3%的增稠剂明胶做添加剂后，三水醋酸钠的过冷性能得到明显改善。

The calculating results which predict that the tip undercooling decreases continuously with an increase of the primary spacing and no minimum undercooling exists have lent an obvious evidence to the above theoretical analyses. The tip undercooling changes sharply for the low primary spacings but slowly for the large spacings.

本文提出的数值模型表明，Peclet数较小时，可以将强制性枝晶生长处理成自适应边界条件进行数值计算；计算结果充分证实了上述的理论分析，并指出顶部过冷随一次间距的增大而连续减小，不存在最小过冷值；一次间距较小时顶部过冷变化显著，较大时变化缓慢。

First, a system for providing liquid refrigerant subcooling (10), subsequent to the subcooling accomplished by the primary condenser of an air conditioner, refrigeration or heat pump system, by means of evaporative cooling utilizing the condenser water of said air conditioner, refrigeration or heat pump system and/or some other water supply to wet the surface of the subcool heat exchanger and then passing the cold, dry building exhaust air (13) required for good indoor air quality across the wetted surface of the subcool heat exchanger or by using building exhaust air only to conductively subcool.

首先，一个提供液态制冷剂过冷的系统(10)，在由空调、制冷或热泵系统的主冷凝器实施完成过冷之后，通过蒸发冷却，利用所述空调、制冷或热泵系统的冷凝器水和/或一些其它水源来润湿过冷热交换器表面，然后使为达良好质量室内空气所需的建筑物干冷排气(13)通过穿过过冷热交换器的润湿表面，或只利用建筑物排气以传导方式过冷。

For supercooling directional solidification, ideal directional microstructure can be obtained only within the supercooling range 63～83K and 127～170K. These two supercooling ranges just corresponds to the supercooling for developed equiaxial dendrites in ordinary supercooling solidification.

6对于深过冷定向凝固来说，只有在63～83K的低过冷度范围和127～170K的中过冷度范围才能获得理想的定向生长组织，而这两个过冷度范围正好对应于深过冷熔体凝固组织为发达的等轴枝晶的过冷度范围，这种组织的相似性似乎与过冷度一样具有遗传性。

Most of such dendrite cores are distributed in the grains with an elliptical morphology; some of them lie in the grain boundaries with triangular or lathy morphologies. There are few dislocations and substructures in the dendrite cores, and there are clear phase boundaries between such dendrite cores and the matrix.

Ni合金过冷熔体中亚稳相和稳定相的竞争形核的计算与实验结果定性吻合，即当熔体过冷度大于某一临界过冷度时亚稳相将作为初生相从过冷熔体中析出，通过分析发现瞬态形核理论能更好的描述深过冷熔体中的竞争形核问题。

Evolution pattern of solidification microstructure in the monophase Cu Ni alloy in the range of thermo dynamically supercooling of 63～292 K is investigated, and both the condition of supercooling degree and orientation mechanism and control method of directional crystalline growth in the melt under negative temperature gradient are analyzed.

研究了 6 3～ 2 92K热力学过冷度范围内，Cu Ni单相合金的凝固组织演化规律，分析了负温度梯度熔体中晶体定向生长的过冷度条件以及晶体生长取向机制与控制方法。结果表明：(1)在临界过冷度ΔT (≈ 10 6K)附近，晶粒细化过程受溶质扩散控制，在临界过冷度ΔT (≈ 2 0 0K)附近，晶粒细化过程受热扩散控制；(2 )在 6 3～ΔT K范围内，晶体的生长方向是 [10 0 ]，在 12 7～ΔT K范围内，晶体的生长方向可以是 [10 0 ]，也可以是

The results reveal that stretch strength of polypropylene is stronger than that of polyvinylidene fluoride membrane and can be equal to that of polysulfone approximately.

另外还研究了过冷度对膜结构的影响，中空纤维外侧过冷度大于内侧过冷度是导致膜内侧比外侧孔隙率高、孔径大的主要原因。

The formation of secondary phase in the non-equilibrium peritectic reaction was observed by precise transmission electron microscopy analysis. The microstructural evolution and phase selection regularities under different solidification velocities were constructed from the laser resolidification experiments. A new phenomenon involving two-phase coupled growth was firstly detected in the rapidly solidified Ti-Al peritectic alloy. The Ti-45Al-2Cr-2Nb alloy with fully lamellar structure ( a 2+ g ) was taken as an object to investigate the possible preparation of bulky metastable g phase materials based on both adjusting the competing nucleation relation and changing the growth kinetics condition.

首先通过过冷合金微观组织分析界定了各包晶合金熔体中各竞争相以初生相出现的过冷度区间；结合高温区的相图计算，从各相形核孕育时间角度揭示了过冷熔体中亚稳相与稳定相的竞争形核关系；通过精细微观组织分析，阐明了远离平衡时包晶反应中次生相的形成机理；在激光重凝快速凝固实验中建立了不同凝固速度下合金的组织与相形成规律，并对包晶合金中两相共生生长行为进行了深入分析；最后选取初生相为 a 的全层片 Ti-45Al-2Cr-2Nb 合金，从调整各相竞争形核关系和改变晶体生长动力学条件两个方面探索了块状亚稳 g 相材料的制备和控制。

On the basis of Bowering Model about ONB of flow boiling using n.

讨论了影响矩形窄缝流道内过冷流动沸腾起始点的各因素，在Bowering关系式的基础上，考虑质量流速和压力对过冷流动沸腾起始点的影响，使用多元线性回归的方法，得到了关于矩形窄缝流道过冷流动沸腾起始点的修正关系式，与实验数据进行比较，误差范围为± 30 %。

The results indicate that MgB2 phase has smaller critical nucleation energy, higher nucleation rate and shorter incubation time comparing with MgB4 phase as the undercooling degree excesses to a critical value at a low undercooling range. Hence, the MgB2 phase nucleates primarily from the melt and grows up.

结果表明：在小过冷度范围内，当过冷度大于某一临界过冷度时，MgB2相比MgB4相具有更低的形核功、更大的形核率和更短的形核孕育时间，因而MgB2相从与MgB4相的竞争形核中胜出，优先从合金熔体中形核并生长。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。