超临界CO_2萃取中药川芎挥发油的工艺优化

目的:研究超临界CO_2流体萃取川芎挥发油的较佳工艺条件。方法:在单因素实验的基础上,采用L9(34)正交实验研究萃取压力(A)、萃取温度(B)、萃取时间(C)及药材粒度(D)对出油率的影响。结果:确定较优提取工艺为A3B2C2D1,即压力45MPa,温度55℃,时间3.5h,药材粒度30目。结论:较佳条件下川芎挥发油出油率为5.49%。     

陶瓷原料粒度和升温速率对差热分析曲线的影响研究

以陶瓷原料中常见的高岭土和围场土为研究对象,考察粒度、升温速率对两种矿物差热分析(DTA)曲线的影响。实验结果表明:不同矿物的粒度、升温速率对差热分析曲线有较明显的影响,即随着试样粒度的增大,差热分析曲线的峰形越来越低,越来越平坦,反应温度滞后;而随着升温速率的提高,差热分析曲线的峰形越来越高,越来越尖锐,反应温度也会发生滞后。     

超临界CO2萃取杜仲叶总黄酮工艺研究

以杜仲叶为原料,研究了超临界CO2萃取杜仲叶总黄酮的工艺条件,并以总黄酮提取率为指标,通过设计L9(33)正交试验研究了萃取温度、压强和时间对超临界CO2萃取杜仲叶总黄酮的影响。结果表明:三因素对提取率的影响顺序为压强>温度>时间,最佳提取工艺条件为温度50℃,压强30MPa,时间120min。同时按照最佳工艺参数进行验证提取,提取率高达10.55%。     

溶剂萃取过程新技术进展

阐述了近年来溶剂萃取的新进展.认为反胶团溶剂萃取、超临界流体萃取、微波萃取、电泳萃取、超声萃取、预分散萃取、磁场协助溶剂萃取、液膜萃取、内耦合萃取反交替分离过程、离子液体萃取等是溶剂萃取发展的新方向.溶剂萃取已成为一项得到广泛应用的分离提纯技术.     

超临界二氧化碳法提取延胡索乙素的研究

对采用超临界二氧化碳从延胡索中提取延胡索乙素的工艺条件进行了讨论。采用正交试验法确定了最佳提取的工艺条件:萃取压力35MPa,萃取时间3.1h,萃取温度60℃,改性剂用量为400ml,在最佳提取工艺条件下,延胡索乙素的产率为0.079%。结果表明,采用超临界二氧化碳提取法比超声波-甲醇提取法(药典法)的产率提高了14.5%。     

柠檬皮中果胶提取工艺研究

以柠檬皮为原料,采用酸水解一盐析法对柠檬果胶的提取工艺进行研究．在单因素试验的基础上,通过正交试验确定了柠檬果胶的提取最佳工艺条件．结果表明：采用酸水解一盐析法可以高效提取柠檬果胶．在试验范围内,萃取液pH、萃取温度、萃取时间、液固比对果胶提取效果均有一定的影响,其中萃取液pH达到极显著,其最佳工艺条件为：以盐酸为萃取剂,萃取液pH为2．0,萃取温度为90℃,萃取时间为100min,液固比为25：1,并选用硫酸铝作沉淀剂．     

橄榄叶中橄榄苦苷不同提取方法的研究

研究超临界CO2萃取、微波和索氏提取法提取橄榄苦苷的最佳工艺。以HPLC检测橄榄苦苷的含量,采用正交实验,对橄榄叶粒度、提取剂用量、提取时间、超临界萃取压力和萃取温度5个因素进行了考察。结果显示,超临界CO2萃取最佳条件为A1B1C3,微波提取最佳条件为A2B2C1,索氏提取最佳条件为A1B3C1。微波提取3min与超临界CO2萃取2 h、索氏提取6h提取的效果相当,微波提取时间短,操作简便,适用于工业化生产。     

溶解结晶法制备精蒽的研究

文章以粗蒽为原料、DMF复配溶剂的最佳结晶条件是保温温度为90℃,保温时间50min,冷却结晶温度为25℃,保温时间50min,固液比1.8g/ml。结果表明:这一方法使溶剂得以循环利用,环境污染小,且成本低,精蒽的纯度可达96%以上,收率达到67%以上。     

超临界CO2萃取除虫菊酯的研究

采用超临界CO2萃取除虫菊中有效成分除虫菊酯。研究了萃取压力、萃取温度对产品的收率和品质的影响，以及CO2流量和萃取时间的关系。其最优化工艺条件为：压力16Mpa，温度40℃，当CO2流量为20m^3/h时，萃取时间为2小时。     

临沧褐煤富集氧化焙烧转化成含锗褐煤灰的研究

研究了采用氧化焙烧法将富集临沧含锗褐煤转化成褐煤灰的适宜条件.结果表明:氧化焙烧的温度、时间、褐煤进料方式和电阻炉升温速率,是影响褐煤灰中锗保留率的因素.富集临沧含锗褐煤氧化焙烧转化成褐煤灰的适宜条件是:先将平铺均匀的富集含锗褐煤置入电阻炉,然后以30℃/min的速率程序升温至600℃,保温氧化焙烧2.5h,所得褐煤灰中锗的保留率大于97%.     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.