Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the gr...Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the great rivers in West China with complicated topographical and geological conditions. Evaluation of stability and safety of these high dam projects is an important topic. Geomechanical model test is one of the main methods to study the global stability of high dam and foundation. In this paper, a comprehensive testing method that combines overloading and strength reduction in a model is proposed. In this method, both the influence of excessive flooding and the effects of strength reduction of rock masses and weak structural planes on dam stability are considered. Thus, the comprehensive testing method can accurately incorporate multiple factors that affect the global stability of high dam and its foundation. Based on the failure testing principle and model similarity theory, a similarity relation formula for safety evaluation through comprehensive test is established. A new model material, temperature-dependent analogous material, is also developed. By rising the temperature and reducing the strength of the mod,~l material, the mechanical behaviors resulting from gradual strength reduction can be simulated. Thus, the comprehensive testing method is realized in a single model. For case studies, the comprehensive geomechanical model test is conducted for Jinpinlg I and Xiaowan high arch dam projects.展开更多
[Objectives]This study aimed to optimize the extraction process of longan(Dimocarpus longan Lour.)leaves by multi-indicator comprehensive evaluation method.[Methods]The contents of gallic acid ethyl ester,astragalin,q...[Objectives]This study aimed to optimize the extraction process of longan(Dimocarpus longan Lour.)leaves by multi-indicator comprehensive evaluation method.[Methods]The contents of gallic acid ethyl ester,astragalin,quercetin,luteolin and kaempferol in longan leaves were determined simultaneously by HPLC.Using the multi-indicator comprehensive evaluation method,the methanol concentration,solid to liquid ratio and extraction time for extraction of longan leaves were optimized by orthogonal test.[Results]The optimal extraction process of longan leaves are as follows:methanol concentration of 100%,solid to liquid ratio of 1∶5,and extraction time of 50 min.[Conclusions]The optimized process is simple and feasible,and it can be used to determine the contents of different ingredients in longan leaves.展开更多
Practical English Test for Colleges (PRETCO) examination is very important to higher vocational college students. Reading comprehension section, moreover, is the key part in the examination because it, in some degree,...Practical English Test for Colleges (PRETCO) examination is very important to higher vocational college students. Reading comprehension section, moreover, is the key part in the examination because it, in some degree, influences the total score of the examination. In this passage, the author is to illustrate some reading methods to help the students master the spirit of reading comprehension and grasp the methods and strategy of then so that they could get high score in this part.展开更多
基金Supported by the National Natural Science Foundation of China (51109152)the National Basic Research Program of China (973 Program) (2010CB226802)the Doctoral Programs Foundation of the Ministry of Education of China (20100181110077)
文摘Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the great rivers in West China with complicated topographical and geological conditions. Evaluation of stability and safety of these high dam projects is an important topic. Geomechanical model test is one of the main methods to study the global stability of high dam and foundation. In this paper, a comprehensive testing method that combines overloading and strength reduction in a model is proposed. In this method, both the influence of excessive flooding and the effects of strength reduction of rock masses and weak structural planes on dam stability are considered. Thus, the comprehensive testing method can accurately incorporate multiple factors that affect the global stability of high dam and its foundation. Based on the failure testing principle and model similarity theory, a similarity relation formula for safety evaluation through comprehensive test is established. A new model material, temperature-dependent analogous material, is also developed. By rising the temperature and reducing the strength of the mod,~l material, the mechanical behaviors resulting from gradual strength reduction can be simulated. Thus, the comprehensive testing method is realized in a single model. For case studies, the comprehensive geomechanical model test is conducted for Jinpinlg I and Xiaowan high arch dam projects.
基金National Natural Science Foundation of China(81560691)Special Fund Project for Innovation Driven Development of Guangxi(Gui Ke AA17202046)+7 种基金Open Program for Construction of TCM Pharmacy Doctor Station in Guangxi University of Chinese Medicine(201410-06)The First-Class Subject of Traditional Chinese Medicine(Ethnic Pharmacy)in Guangxi(Gui Jiao Ke Yan[2018]No.12)Program of Collaborative Innovation Center of Zhuang and Yao Medicine(Gui Jiao Ke Yan[2013]No.20)Program of Key Laboratory of Zhuang and Yao Medicine[Gui Ke Ji Zi[2014]No.32]The Eighth Batch of Special Experts Project of Guangxi Zhuang Autonomous Region(Study on Quality Standard of Zhuang&Yao Medicine,[2019]No.13)High-level Talent Team Cultivation Program of"Qihuang Project"of Guangxi University of Chinese Medicine(2018002)High Level Innovation Team and Excellent Scholar Program of Guangxi Universities(Gui Jiao Shi Fan[2019]No.52)Guangxi One Thousand Young and Middle-aged College and University Backbone Teachers Cultivation Program(Gui Jiao Ren[2019]No.5).
文摘[Objectives]This study aimed to optimize the extraction process of longan(Dimocarpus longan Lour.)leaves by multi-indicator comprehensive evaluation method.[Methods]The contents of gallic acid ethyl ester,astragalin,quercetin,luteolin and kaempferol in longan leaves were determined simultaneously by HPLC.Using the multi-indicator comprehensive evaluation method,the methanol concentration,solid to liquid ratio and extraction time for extraction of longan leaves were optimized by orthogonal test.[Results]The optimal extraction process of longan leaves are as follows:methanol concentration of 100%,solid to liquid ratio of 1∶5,and extraction time of 50 min.[Conclusions]The optimized process is simple and feasible,and it can be used to determine the contents of different ingredients in longan leaves.
文摘Practical English Test for Colleges (PRETCO) examination is very important to higher vocational college students. Reading comprehension section, moreover, is the key part in the examination because it, in some degree, influences the total score of the examination. In this passage, the author is to illustrate some reading methods to help the students master the spirit of reading comprehension and grasp the methods and strategy of then so that they could get high score in this part.
