Gelation Mechanism of Erythromycin Ethylsuccinate During Crystallization     

Xiandong Su  Zhenguo Gao  Ying Bao  Miao Guan  Sohrab Rohani  Qiuxiang Yin  Hongxun Hao  Chuang Xie  Jingkang Wang 《天津大学学报(英文版)》2019,(2)

In this paper, the gelation mechanism of erythromycin ethylsuccinate(EES) during crystallization is investigated for the first time. The generated semisolid gel-like phase exhibited a 3D fibrillar network morphology and the typical rheological properties of gels. The fibers inside the gel-like phase were confirmed to be new types of EES solvates using powder X-ray diffraction, thermogravimetric analysis/differential scanning calorimetry, and gas chromatography. The gelation and crystallization regions in EES-1-propanol solid–liquid phase diagram were determined. Analyses of solvent parameters showed that moderate solvent polarity may promote EES gelation. Fourier transform infrared spectra, nuclear magnetic resonance spectra, and scanning electron microscopy analyses indicated that through intermolecular hydrogen bonds, EES and solvent molecules assembled into fibers via crystallographic mismatch branching growth. The fibers intertwined into a 3D network microstructure and formed a gel-like phase, completely immobilizing the solution.  相似文献   

高等学校扩建面临的机遇和问题研究     

李创 《黑龙江高教研究》2006,(8):27-29

高等学校扩建面临多种机遇:社会发展进程、各级政府政策支持、舒缓就业压力、教育的投资和消费等推动了高等教育的发展。但是高校扩建中会遇到教育资源不足、筹资渠道有限、生源竞争激烈、投资效益不高等问题,亟待解决。  相似文献   

Primary Grades Teachers’ Instructional Decisions During Online Mathematics Professional Development Activities     

Drew Polly  Christie S. Martin  Chuang Wang  Richard G. Lambert  David K. Pugalee 《Early Childhood Education Journal》2016,44(3):275-287

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在传统与保守中获取自由——论大学传统与保守的文化品格及当下意义   总被引：3，自引：0，他引：3  

刘创 《教育研究》2004,(4)

大学传统与保守的文化品格形成具有必然性和合理性,其发展与升华的最高境界是自由,自由教育是其精神内核。大学传统与保守文化品格的形成与超越,必须坚持自由探索的原则,坚持“教育重于教学”的思想,保守人文教育传统,实现自由教育与职业性教育的调和发展,达到保守性与进取性的均衡和谐状态。  相似文献   

EPR-RCGA-based modelling of compression index and RMSE-AIC-BIC-based model selection for Chinese marine clays and their engineering application     

Ze-xiang Wu  Hui Ji  Chuang Yu  Cheng Zhou 《浙江大学学报(A卷英文版)》2018,19(3):211-224

The compression index is a key parameter in the field of soft clay engineering. In this paper, we propose an improved method for correlating the compression index with the physical properties of intact Chinese marine clays that are involved in many construction projects in coastal regions in China. First, the compression index and some common physical properties of clays from 21 regions along the Chinese coast are extracted from the literature. Then, a basic regression analysis for the compression index using the natural water content and Atterberg limits is conducted. To improve the correlation performance, an evolutionary polynomial regression (EPR) and real coded genetic algorithm (RCGA) combined technique is adopted to formulate different equations involving different numbers of variables. An optimal correlation using only natural water content and liquid limit as input parameters is finally selected according to the root mean square error (RMSE), Akaike’s information criterion (AIC), and Bayesian information criterion (BIC). The proposed correlation is evaluated and shown to perform better than existing empirical correlations in predicting the compression index for all selected Chinese marine clays. This correlation is validated to be reliable and applicable to engineering applications through the prediction of the properties of an embankment on the southeast coast of China using finite element method. All comparisons show that the EPR and RCGA combined technique is powerful for correlating the compression index with the physical properties of the clay, and that model selection by RMSE, AIC, and BIC is effective. The proposed correlation could be used to update current formulations, and is applicable to engineering design in coastal regions of China.  相似文献   

Group trust,communication media,and interactivity: toward an integrated model of online collaborative learning     

Jianxia Du  Chuang Wang  Jianzhong Xu  Xitao Fan  Saosan Lei 《Interactive Learning Environments》2018,26(2):273-286

The present investigation examines the multidimensional relationships among several critical components in online collaborative learning, including group trust, communication media, and interactivity. Four hundred eleven university students from 103 groups in the United States responded survey items on online collaboration, interactivity, communication media, and group trust. Structural equation modeling was employed to examine the relationships among these variables. Results revealed that trust among group members had a positive and powerful influence on online collaboration. Results further revealed that the influence of group trust on online collaboration was mediated by communication media and the interactivity among group members. These findings are discussed in the context of existing literature in the field. Practical implications and directions for future investigation are provided.  相似文献   

对"分层次教学"的认知   总被引：4，自引：0，他引：4  

孙闯  王凤娥 《沈阳教育学院学报》2004,6(3):56-59

分层递进教学是体现“教适应学——选择——发展”教学理念的一种方略。本文将对分层递进教学的概念、提出、依据、哲理、类式和优势的认知阐明见解。  相似文献   

加强形成性考核管理提高电大学生素质     

刘创 《湖南广播电视大学学报》2001,(3):28

加强电大形成性考核管理,使之规范化、科学化,是提高电大教学质量,提高电大学生素质的重要途径.  相似文献   

The correlation between epistemological beliefs and preferences toward Internet-based learning environments     

Chin-Chung Tsai  Shih-Chyueh Chuang 《British journal of educational technology : journal of the Council for Educational Technology》2005,36(1):97-100

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新《体育法》实施背景下我国体育赛事活动安全监管立法:现状、问题及优化     

蒋亚斌  张恩利  孔维都  张敏昊  焦创  张佳星 《南京体育学院学报(社会科学版)》2023,37(3):76-86

体育赛事活动监管立法是实现依法治体、依法监管的基础与前提。研究以新《体育法》实施为背景,综合运用文献资料、逻辑分析和文本分析等研究方法,从立法结构、立法内容等基本要素着手, 系统梳理了我国现行的体育赛事活动法律规范体系。研究发现,现行立法存在整体立法层级偏低、监管要素呈现不全面、地方立法创制水平较低、立法时效性欠佳和软硬法互补效应不强等问题。为此,研究提出未来可通过统筹央地立法进程,整体提升体育赛事活动监管立法层次;贯彻落实职权法定,进一步明确体育赛事活动监管细节要素;顺应监管实践需要,适度提升地方立法的创制性;坚持立改废释并举, 有效增强立法时效性;建立健全行业规范体系,逐步优化体育软硬法的衔接和互补等方式,不断优化我国体育赛事活动安全监管的法律规范体系。  相似文献