Metastable state of clindamycin phosphate in cooling crystallization

The metastable state and nucleation kinetics of clindamycin phosphate （CP） in cooling crystallization were studied by metastable zone width （MZW） method and induction time method. By correlating the MZW experi- mental results with temperature, agitation rate and cooling rate, it is found that the correlation result shows good agreement with the change trend of MZW. The critical nucleation parameters were evaluated based on the classical theory of nucleation; both the interfacial tension and the radius of critical nucleus increased with the decrease of rela- tive supersaturation. The effect of supersaturation on the nucleation rate was analyzed. It is indicated that the new phase formation of CP is governed by mononuclear mechanism.     

Preparation and characterization of TiO2/expanded graphite

In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high temperature. The samples were analysed by using scanning electron microscope (SEM), X-ray diffraction(XRD), energy disperse spectroscopy(EDS), and differential scanning calorimetry(DSC). The optimal conditions for preparation are as follows: the molar ratio of tetrabutyl orthotitanate to triethanolamine is 1∶0.4, and the calcination and expansion temperature is in the range of 650-750 °C. Under such conditions, the expansion volume of composites could reach 98 mL/g, and the mass loss ratio is less than 5%. The analysis shows that lower temperature and smaller particle size of graphite are helpful to the formation of anatase-type of TiO2, but larger particle size will lead to lower mass loss ratio, and higher temperature and larger particle size will lead to higher expansion volume.     

在阅读教学中如何贯穿识字教学

中国汉字承载着6000多年来的中华文明,是中华民族智慧的结晶和无价的瑰宝,是我们中华民族的骄傲!那么,如何让这一瑰宝得以传承呢？这里我想可以套用一句名言“识字应从娃娃抓起”,对于一名小学教育工作者来说,识字教学就显得极其重要。那么识字教学的现状怎么样呢？     

起承转合法

文无定法,但行文有法。法,就是方法、技巧。这不是哪个人凭空杜撰的产物,而是千百年来无数人写作实践的结晶。起承转合法是议论文布局的基本技巧之一。     

《容积和容积单位》教学设计与分析

教学目标：1．知道容积的含义,理解体积和容积之间的联系与区别。2．认识常用的容积单位升与毫升,初步建立升与毫升的容积观念。3．培养观察、独立思考和应用几何基础知识解决实际问题的能力。教学重、难点：知道容积的含义,掌握容积单位间的进率;量（升、毫升）感的培养。     

薪火相传 师之大爱——国学教育滋养教师成长

国学是我国传统学术文化,内容博大精深,在漫长的历史长河中,作为中华文明的主要载体,其思想文化的精髓已超越时空,成为传之千古、播之四海的人类共有智慧结晶。     

声音

这是一个教育家群起的时代。 ——教育家何在？大量存在于教师之中,特别是在广大中小学教师之中。但其中的多数还处于一种模糊状态,并未从教师中结晶析出,而是处于一种和广大教师水乳交融在一起的自然状态。我们可称之为潜在的教育家。过去我们把教育家看得很神秘甚至高不可攀,压抑了广大教师成为教育家的积极性和为此所作出的努力。     

工业用七水硫酸锌结晶设备改造

介绍了七水硫酸锌(ZnSO4·7H2O)几种常用结晶方法及设备,分析了其存在的问题,提出了解决七水硫酸锌(ZnSO4·7H2O)生产能力的新工艺及设备,并在实践中得到了验证,运行3年,效果良好.     

浅析结晶在氮肥生产中的应用

晶体在溶液中形成的过程称为结晶。本文探讨了结晶在氮肥生产中的应用。