成核

The nucleation effect of nucleating agent HC (mainly containing salt of high molecular carboxylic acid) on polyoxymethylene was studied, and the effects of the nucleating agent on the crystalline morphology, crystallizability and crystallization rate of POM were also studied by means of DSC, PLM and isothermal crystallization kinetics analysis.

研究了高摩尔质量羧酸盐类成核剂HC对聚甲醛的结晶成核作用，采用示差扫描量热分析、偏光显微镜观察及等温结晶动力学分析等方法研究了该类成核剂对POM结晶形态、结晶度、结晶速率等的影响，并考察了其力学性能。

In this paper the nucleation of nucleator C to polyacetal was investigated by means of DSC, PLM, WAXD and testing of mechanical properties.

本文利用差热分析仪、偏光显微成核剂的作用镜、广角X射线衍射仪及力学性能测试设备考察了成核剂C对聚甲醛的成核作用。

Crysalline shape and behavior were investigated by polarizing microscope and wide angle X-ray diffraction spectrum.The results show that the value of impact strength is maximum while tensile strength,flexural strength,modulus and vicat softening temperature are least when the content of β form nucleator is 0.05 phr.

结果表明，当β成核剂的含量在0.05份时，冲击强度达到最大值，而拉伸强度、弯曲强度、模量、维卡软化温度等达到最小值；当β成核剂含量为0.05份以下时，随着β成核剂含量增加，PP中β晶结晶度大幅度上升，同时α晶结晶度大幅度下降；增加β成核剂用量至大于0.10份时，β晶结晶度略为下降，而α晶结晶度上升，但总结晶度随着β成核剂含量增加呈现上升趋势。

Through the experiments on hydration of AH in the following sulphate（Li_2SO_4、MgSO_4 、 Al_2(SO_4)_3 、MnSO_4 、CuSO_4 、CoSO4 、CdSO_4 、ZnSO_4 、NiSO_4 、FeSO_4）, dissoluble sulfate hydrate origining from hydration process of AH affects it's hydrous rate, hydrous rate of AH does not connect with Z/R of cation in stimulation, theory that Z/R affect hydrous rate of AH does not exist. Third, hydration of AH in dissoluble sulfate complies with dissolve-nucleate -grow theory, concentration of Ca~2+ from dissolving of CaSO_4 is higher than one of CaSO_4·2H_2O, calcium sulphate dihydrite gets a motivity of crystallization. dissoluble sulfate takes the following function: double-salt or dissoluble sulfate hydrate from hydration of AH in it becomes heterogeneous particle and a kind of nucleation catalyzer, and reduces surface barrier when DH becomes crystal because the crystal of DH precedently appears in uneven place. Results indicate hydration of AH does not conform with double-salt theory, but it conform with this mechanism: dissolve-nucleate-grow, formation of DH is an uneven nucleation and crystalizaion process.

通过对CaSO_4在Na_2SO_4 、K_2SO_4 、Rb_2SO_4 、Cs_2SO_4 、(NH_4)_2SO_4溶液中水化过程，以及CaSO_4·2H_2O、CaSO_4与以上硫酸盐反应速度、产物的研究，说明复盐理论不正确；CaSO_4在（Li_2SO_4、MgSO_4 、 Al_2(SO_4)_3 、MnSO_4 、CuSO_4 、CoSO_4 、CdSO_4 、ZnSO_4 、NiSO_4 、FeSO_4）溶液中水化，水化过程中硫酸盐水合物的析晶影响着无水硫酸钙水化，与激发剂阳离子Z/R值大小无关，阳离子的Z/R参数影响水化率的规律并不存在； 3、无水硫酸钙在可溶性硫酸盐中的水化按照溶解-成核-生长理论进行，CaSO_4达到溶解平衡时Ca~2+的浓度大于CaSO_4·2H_2O溶解平衡的Ca~2+的浓度，CaSO_4·2H_2O获得结晶的驱动力，可溶性硫酸盐起到形成晶核的作用：水化过程与CaSO_4生成复盐或析出水合物所形成的细小物相，作为异质微粒使母相中存在不均匀性，这些不均匀性有效地降低成核时的表面能位垒，使CaSO_4·2H_2O晶核优先地在这些具不均匀性的地方形成，因此这些物质起成核催化剂作用。

The content of the irregular bigger drop phase approached to pyrope. It showed that the crystallization and phase separation mechanics of the glass was the nucleation-and-growth transformation and the crystallization is bulk crystallization. The activation energies of phase separation and crystallization were calculated by the modified Kissinger method, about 310.445 KJ/mol and 249.26 KJ/mol respectively. Using the aluminum hydroxide as the reference, we calibrated the phase separation exothermal enthalpy of the quenched and nucleation treated glass, ca

钠镁侣硅系统徽晶玻瑞快速徽晶化机理的研究利用上式求得混合系统中两相的单位体积相变自由能、两相间的表面能和相互作用参数，分别为刁。6753xlo3了zcm3·、3ss.gozzem3、5.316xlo一JzcmZ和一442 xlol，进而求得球形核的临界半径为nnm，以及一个临界核的成核自由能变化为2石89 x10一14/cm3；成核半径16.5纳米时，球形核稳定存在，实测 1752个球形核中最小核半径为20纳米，与计算结果基本吻合。

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 DSC results showed that calcium carbonate,sodium benzoate and terephthalic acid were the nucleating agents of polypropylene with high thermal stability of the nucleating effect,while the thermal stability of nucleating effect of pimelic acid,suberic acid,azelaic acid,and the two component nucleating agents suberic acid/calcium carbonate and azelaic acid/calcium carbonate were poor.

研究了碳酸钙、苯甲酸钠、对苯二甲酸和脂肪二元酸：庚二酸、辛二酸、壬二酸及其与碳酸钙组成的双组分成核剂对聚丙烯结晶成核效果的热稳定性。结果表明，高熔点物质碳酸钙、对苯二甲酸、苯甲酸钠的成核效果的热稳定性高，而脂肪二元酸的成核热稳定性低。庚二酸与碳酸钙组成的双组分成核剂的成核热稳定性高，但辛二酸、壬二酸与碳酸钙组成的双组分成核剂的成核热稳定性没有得到改善。

According to classical nucleation theory, it was possible to distinguish the homogeneous and heterogeneous nucleation from the influence of temperature and supersaturation on induction period.

本文根据经典均匀成核理论，分别研究了硝酸酸沉和盐酸酸沉制备的四钼酸铵过饱和溶液的成核过程，并讨论了过饱和比和温度对成核速率及成核机制的影响。

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。

To analysis crystallization kinetic equations, it was showed eligible stirring rate dependency and the high order dependence on supersaturating, which suggested that crystal growth of 6APA was surface integration controlled.

浓度推动力对于成核速率大于搅拌速率以及悬浮密度的影响，表明6APA成核过程同时包括了初级非均相成核以及二次成核；搅拌速率对6APA成长速率的极小影响以及过饱和度的较大影响，说明在试验条件下6APA晶体生长为表面反应控制。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。