查询词典 nucleation

It introduced the classical theory of bubble nucleation during the process of foam plastics , and presented the calculation formulas about the radius of critical nucleation , required Gibbs free energy and nucleation rate of some kinds of nucleation. It reviewed the development of classical theory of bubble nucleation , including the influence of free volume and oversaturation on bubble nucleation , and pointed out the existing deficiencies in explanation of classical theory of bubble nucleation to bubble nucleation of dynamic polymer melt.

介绍了泡沫塑料加工过程中气泡成核的经典理论，给出了几种成核方式的临界成核半径、所需克服的吉布斯自由能及成核速率的计算公式；评述了经典成核理论的发展，包括自由体积和气体过饱和度对气泡成核的影响，并分析指出了经典成核理论对动态聚合物熔体气泡成核解释存在的不足。

Based on the classical nucleation theory and the time-dependent nucleation theory, the thermodynamics and the kinetics for the nucleation of decagonal quasicrystal have been discussed in det...

大量实验结果表明，惰性形核涂层的非晶化程度、熔体过热度、过热保温时间以及循环过热次数等工艺参数将显著影响熔体的初始过冷度。

The results point out that the values of kinetic parameters are altered with the addition of Ti and C, which change the crystallization type from difficult nucleation and easy growth pattern to easy nucleation and difficult growth pattern, and this difficult nucleation and easy growth pattern may be the main reason why fine and even microstructure is gained in Ti and C doped alloys.The influences of Nd content, B content, partial substitution of Nd by Pr on the microstructure and magnetic properties have also been researched.

文章从动力学理论的观点揭示了合金显微结构与合金晶化动力学特性之间的关系，指出Ti和C添加改变了Nd9.4Fe79.6B11合金晶相析出时的动力学参量值，使合金晶化时晶相的析出方式由难形核易长大型加热管转变为易形核难长大型，这种易形核而难长大的晶化动力学特征，是Ti和C添加合金获得细小均匀的纳米晶结构的根本原因。

The growth and nucleation rates of〓 cleavage face of YbYAB crystal are all very fast, because so many growth steps and growth centers were formed within only 2～3 second at the temperature near the saturate point. No spiral growth steps can be found, so growth mechanism is twodimensional nucleation. When the flux temperature increases for only 0.5℃ above the saturate point, the spiral melting holes are formed. The transformation from growth morphologies to melting morphologies is very sensitive to the temperature. When the temperature increases another 1℃, the spiral melting holes transform into two-dimensional nucleation melting holes.

YbYAB的〓解理面的生长及成核速度都非常快，在比饱和点低0.5～1℃的温度下，当生长2～3秒钟时，可以看到许多生长中心与生长台阶的形成，在较宽的台阶上还可以看到二维核的形成，没有看到螺旋中心，说明生长机理是二维成核生长；当温度比饱和点高0.5℃时，在〓解理面上形成螺旋状熔坑，这表明形貌由生长到熔化的转变与温度的关系是非常敏感的；当温度比饱和点高1.5℃时，螺旋状熔坑转变为二维成核状熔坑。

The fundamental researches on ice crystals generating in statice supercooled water are analysed in this article. And homogeneous nucleation and heterogeneous nucleation ways of nucleation process are analysed and calculated. In general , water may freeze in tube and most likely blockage occur in the end, which make the unstable-instability of the system.

一般情况下，水在管内会发生结冰极并极可能产生冰堵，会造成系统运行的不稳定，本文对过冷水在管内结冰的影响因素进行了分析，并结合实验装置进行了相关实验，指出对冷却壁面的温度和表面状况进行控制是防止结冰的关键影响因素。

It was found in this investigation that boron exerted considerable influenceon the nucleation and growth of pearlite. In a hypoeutectoid steel, boron delayedthe starting time of pearlite formation at the maximum pearlite formation temp-erature. Boron did not effect the relation of nucleation rate with time butonly increased the incubation period for pearlite nucleation.

从实验结果证明，硼对珠光体的成核及成长是有影响的；在亚共析钢中硼促使珠光体的开始形成时间推迟，增长了珠光体成核的孕育期，但对成核率与时间的关系，在近于A_1温度(700℃)时，略为加速，而在珠光体转变速度最大的温度(650℃)时却没有影响。

The homogeneous nucleation rate, saturation rate, and droplet growth equation at state 250K、100Kpa for pentone affected by single expansion wave has been obtained in the joined international cooperation research. Results exposed that temperature decrease in the homogenous nucleation and condensation is the preponderant factor in unsteady adiabatic expansion process.

参与同质核化率实验的国际合作研究，获得250K、100KPa状态附近戊醇在单脉冲膨胀波作用下的同质核化率、饱和度及同质核化微滴在低压状态中长大状态方程；研究表明非定常绝热膨胀过程中，降温因素在同质核化和凝结过程中占主导作用。

The results show that the glass-ceramics with fibroid structure is produced after definite heat treatment, the main crystallization phase is hedenbergite and anorthite is the minor crystallization phase. The optimal process of heat treatment shows as follows: the nucleation temperature is 850 ℃ and hold time is 100 min, and the crystallization temperature is 980 ℃ and hold time is 80 min. With increasing heat treatment temperature, the FT-IR absorption bands appear obvious split, the aluminum-oxide polyhedron in the glass network changes from [AlO4] to [AlO6]. The titanium ion in the glass network gradually transforms to the 6-coordinated, moreover forms minicrystal of MgTi2O5 and Fe2TiO4 which provides the position of heterogeneous nucleation for the growth of crystal.

结果表明：在一定的热处理条件下可以以基础玻璃制备出主晶相为钙铁透辉石，次晶相为钙长石的纤维状结构的微晶玻璃；最佳的热处理工艺为：850 ℃核化100 min，980 ℃晶化80 min；随着热处理温度的升高，红外吸收带发生明显的分裂；玻璃结构中的[AlO4]向[AlO6]转化；网络结构中的钛离子逐渐转变为六配位，形成微晶相——钛酸镁和钛铁晶石，为晶体的生长提供非均匀形核位置。

Nd and Y showed more evident effects than Gd and La due to lower temperature of eutectic reaction with aluminum. In order to investigate mechanism of the formation of the intercellular dispersoid which is being in debate and possibility of suppressing the dispersoid, a nucleation kinetic model which including unsteady nucleation and effect of alloy element was established.

Al-Fe-Mo-Si-Zr-Ti合金粉末具有四种凝固组织，初生Al〓〓，α-Al与Al〓共晶，胞晶及显微胞晶，合金元素Mo的加入，显著提高合金粉末凝固前的过冷度，使10~40μm粉末的凝固机制发生了变化，由导热控制型转变成溶质扩散控制型，从而基本上消除了该尺寸范围内粉末凝固组织中共晶成分和初生相，但对大于40μm的粉末，因共晶区富Zr核心的优先形成而使Mo的作用效果不明显。

The sloping plate can provide sufficiently the under-cooling for nucleation and lay a foundation for heterogeneous nucleation to form lots of nuclei of crystal internally and on the sloping plate surface, thus causing the melt to nucleates eruptively. Under the action of both metal flow and vibration, the nuclei formed on the sloping plate surface can move freely and disperse into the melt, and they are able to maintain the direct growth in spherical shape in the homogeneous composition and temperature fields.

倾斜板为形核提供足够大的过冷度和异质形核基础，大量晶核在斜板表面和内部形成，使熔体爆发形核，在流动和振动作用下斜板表面形成的晶核游离，弥散到熔体内部，晶核在均匀的成分场与温度场条件下，可以保持直接球状生长。

Diabetes is a social disease that affects several million people worldwide.

糖尿病是一个社会性疾病，全世界有数百万人罹患此病。

I'll call you on Friday to see if we can reschedule our luncheon meeting at your convenience.

我星期五会给您打电话在您方便的时候我们重新安排我们的午餐约会。