过冷

The theoretical and testing research results show that inhomogenous microzone of construction ,conce-tration and energy in austenite ,which is in demand for unusual decomposition of undercooling austenite ,can be obtainedby controlling heating or plastic deformation or controlling cooling.

通过理论和试验研究表明，过冷奥氏体异常分解所需要的奥氏体内在结构上、浓度上和能量上的不均匀微区，可以借助于加热过程控制或塑性变形、或冷却过程控制来获得。

Density Functional Theory method was used to optimize the geometries of 209 PCDE molecules, 209 PBDE molecules and 75 PCDD molecules at the B3LYP/6-31G* level. Using computed structural parameters as theoretical descriptors, the forward stepwise multiple regression technique was adopted to obtain QSPR models of environmental partition properties for these POPs by using GQSARF 2.0 and SPSS12.0 for windows programs. The obtained QSPR models are as follows:(1) QSPR models for predicting subcooled liquid vapor pressure, n-octanol/water partition coefficients lgK_(ow and subcooled liquid water solubilities -lgS_(w,l of PCDEs, of which correlative coefficients (R~2) are 0.988, 0.958 and 0.959 and the root-mean-square-error of estimation are 0.134, 0.116 and 0.327 respectively.(2) QSPR models of lgPL and n-octanol/air partition coefficients lgK_(oa for PBDEs, which both contain three structural parameters. The values of R2 for the two models are both 0.997 while the values of RMSEE are 0.073 and 0.062 respectively.(3) QSPR models of lgKow and–lgS_ for PCDEs, which both have one variable (mean molecular polarizability,α). The values of R~2 for the two models are 0.978 and 0.866 and the values of RMSEE are 0.300 and 0.270 respectively.(4) The molecular structures of 24 substituted naphthaline compounds were optimized using Hartree-Fock and DFT methods at four different levels and the same means was used to obtain four three-parameter (EHOMO, q~+ andα) QSPR models of lgK_. The model at the HF/6-311G** level is the best one of which R2 is 0.9662 and RMSEE is 0.380.(5) QSPR study for environmental partition properties of PCDEs was also performed using position of Cl substitution method in which simple parameters of substitution position were taken as descriptors. The multiple linear regression was performed with GQSARF 2.0 and SSPS 12.0 for windows programs to obtain QSPR models of lgP_L, lgK_ and–lgS_ for PCDEs of which R~2 are 0.991, 0.983 and 0.965 and RMSEE are 0.311, 0.100 and 0.300 respectively.

采用密度泛函理论方法在B3LYP/6-31G*水平上对PCDEs、PBDEs和PCDDs的分子结构进行了全优化计算，以计算得到的量子化学参数作为理论描述符，采用GQSARF 2.0和SPSS 12.0 for windows统计程序进行正向逐步回归分析，建立了这些POPs的环境分配性质的QSPR模型：(1) PCDEs的过冷液体蒸汽压、正辛醇/水分配系数lgK_(ow和水溶解度-lgS_(w，l的QSPR模型，这3个QSPR模型的相关系数(R2)分别为0.988、0.958和0.959，估计的均方根误差分别为0.134、0.116和0.327；(2) PBDEs的lgPL和正辛醇/空气分配系数lgK_(oa的QSPR模型，这两个模型都包含三个分子结构参数，其R~2都为0.997，RSMEE分别为0.073和0.062；(3) PCDDs类化合物的lgK_和-lgS_w的QSPR模型，两个模型都只含一个变量，其R~2分别为0.978和0.866，RSMEE分别为0.300和0.270；(4)采用Hartree-Fock和DFT方法，在4种不同水平上优化计算了24个取代萘系列化合物的分子结构，采用上述同样的方法分别建立了四种水平上的三变量lgK_模型，通过比较得到，在HF/6-311G**水平计算得到的模型最好，R为0.966，RSMEE为0.380；(5)同时，采用氯原子取代位置方法对PCDEs的环境分配性质进行QSPR研究，建立了PCDEs的lgPL、lgK_和-lgS_的QSPR模型，其R~2分别为0.991、0.983和0.965，RSMEE分别为0.110、0.100和0.300。

Aimed at the over proof problem of dissolved oxygen in condensation water for 300 MW units, a great deal of tests have been made, this paper deals with the effects of feed water pump sealing water, seal steam heater drain water, overcool degree of condensation water , and condenser makeup water, and puts forward some effective improving measures.

针对某电厂300MW机组凝结水溶氧超标的问题，进行了大量的试验研究，提出了给水泵密封水、轴加疏水、凝结水过冷度以及凝汽器补水等对凝结水溶氧量的影响，并对此提出了一些行之有效的改进措施。

The coarse grain in cast strip is produced on the condition that cool speed is not fast enough to overcool aluminum melt in whole cast area, and only provide proper temprature gradiant to keep cellular grain growing up.

铸轧区内铝液与铸轧辊接触瞬间，当铸轧辊冷却强度不足以使整个断面铝液同时产生较大的过冷，而仅能保持胞状晶生长所需的液体温度梯度时，铸轧板就会出现粗大晶粒；根据传热学原理，分析了具体生产条件，提出增大铸轧辊冷却强度、降低前箱温度以及添加铝钛硼丝等防止铸轧板产生粗大晶粒的措施。

The results show that if the initial crystal nucleus is not melted, its size has nothing to do with the simulation results. With the coefficient of interfacial anisotropic strength increasing, the dendritic tip's growing speed increases linearly, while its radius decreases parabolically. The lower the sub-cooling degree is, the more difficult it is to find secondary dendrites.

结果表明：在保证初始晶核不被熔化的前提下，初始晶核半径r0的大小不影响模拟结果；随着界面各向异性系数的增大，枝晶尖端生长速度以线性方式增大，而枝晶尖端半径以抛物线方式减小；过冷度越小，枝晶的生长越困难，越不能出现二次枝晶。

Moreover, with the increase of undercooling, the volume fraction of peritectic phase increases and microstructure refinement occurs.

随着过冷度的增大，包晶相体积分数增大，两相枝晶发生细化。

The achievements of recent extensive experimental and theoretical researches on the morphological instabilities of eutectic and peritectic coupled growth were reviewed.

这些成果主要包括：片层共晶共生生长在最小过冷度下的超稳定性、片层共晶共生生长的Z字形分叉、熔体流动及非线性动力学对共生生长形态稳定性的影响等。

Quotiety of heat exchange on side of air and parameter of refrigerant inside of tube is calculated.

毛细管仿真：在采用毛细管作为节流元件的制冷装置中，毛细管的选用与制冷剂的冷凝压力，过冷度和蒸发压力等因素有关，理论计算比较繁琐。

A separated model is developed for the recirculating flow and heat transfer in a kettle reboiler tube bundle.

提出了釜式再沸器管束中循环流动换热的分相预报新模型，考虑了管束下部的过冷沸腾及循环液体的侧面引入。

There is an active growth layer and super cooled water exists with ice crystals that may be an important feature layer to occur rain in stratiform cloud.

过冷水滴和冰晶共存层存在，且冰晶活跃增长，此层的存在可能是发生降水的关键。

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。