离子交换树脂层析纯化菜籽卵磷脂的工艺研究

探讨以菜籽水化脱磷油脚为原料,通过离子交换树脂层析纯化菜籽磷脂酰胆碱(PC)的工艺过程,对工艺条件进行优化。首先通过丙酮、石油醚等溶剂萃取工艺,制备出菜籽粉末磷脂,然后利用离子交换树脂纯化PC。确定高效液相检测方法为PC的定量、定性分析方法,对柱层析工艺进行优化。结果表明,柱层析的最佳工艺条件为：单位树脂上样量0.08 g·mL^-1;流速3.0 mL·min^-1;上样浓度0.1 g·mL^-1;高径比10∶1;前300 mL用95%乙醇洗脱,后150 mL用含异丙醇40%的异丙醇/水溶液洗脱。经HPLC-ELSD定量分析,产品纯度和回收率分别为72.3%和72.6%。     

枸杞色素提取工艺研究

对枸杞色素的提取工艺条件进行了初步研究.结果表明:枸杞干果预处理条件为0.7mol/L的Na2CO3皂化30min,0.5mol/L稀硫酸中和起泡pH为7.5,离心后无水乙醇浸泡10min;枸杞色素最佳提取条件为:提取溶剂为1∶4乙酸乙酯乙醚溶液,料液比1∶10,提取温度40℃,时间3h.     

引入“探究教学模式”培养学生的综合能力

为了培养学生的科研意识和综合能力,在经典的基础有机化学实验——乙酸乙酯的合成中引入"探究教学模式"。在合成实验基础之上增加了粗产品纯化过程在线跟踪、产品中乙酸乙酯纯度分析、杂质种类与含量分析以及乙酸乙酯结构表征的实验教学内容,分别采取气相色谱和便携式微型核磁共振波谱仪(45 MHz)进行分析,并比较了产品经气相色谱氢火焰离子化检测器FID和热导检测器TCD分析结果的差异。这种探究教学模式,不仅训练了学生基本操作技能,同时培养了学生的多角度思考问题的能力。     

冷水花药材的薄层指纹图谱研究

采用硅胶GF254板,分离冷水花80%乙醇提取物中石油醚和乙酸乙酯两个萃取部位的化合物,分别以石油醚-三氯甲烷-丙酮(5∶0.5∶1)、石油醚-三氯甲烷-丙酮(2∶1∶1)为展开系统,对上述两个萃取部位进行薄层色谱研究.实验得到的冷水花药材各萃取部位的薄层指纹图谱斑点清晰,能有效鉴别冷水花药材.     

地瓜藤提取物的GC-MS成分研究

目的：研究地瓜藤（Ficus tikoua Bur）石油醚及乙酸乙酯提取部分的化学成分。方法：地瓜藤经乙醇渗漉提取,采用溶剂提取法进行分离纯化,得到的单体化合物,根据理化方法及气相色谱-质谱联用分析鉴定法鉴定其结构。结果：分离出穿贝海绵甾醇、邻苯二甲酸二丁酯、4-羟基-3-甲氧基苯甲酸、邻苯二甲酸二异丁酯、邻苯二甲酸二乙基己基酯、十八酸等33种化学成分,其中32种化合物是首次从该种植物中提取得到的。     

河蚬壳制备柠檬酸钙的工艺研究

以河蚬壳为原料,采用二次高温煅烧法获得较高纯度的CaO,溶于水后调成石灰乳,与柠檬酸进行中和反应制备柠檬酸钙。探讨河蚬壳高温煅烧的工艺条件和河蚬壳煅烧产物的纯化工艺条件,并采用正交试验设计法优化确定柠檬酸与河蚬煅烧物中和反应制备柠檬酸钙的最佳条件。结果表明,取二次煅烧后的产物0.3 g,加水12 mL调成石灰乳,与10 mL,1.2 mol·L-1柠檬酸于70℃下反应30 min,制得柠檬酸钙0.799 8 g,产品经原子吸收分光光度法测定含钙量21.76%,经红外图谱定性分析符合目标产品特性。     

中药厚朴中厚朴酚、和厚朴酚的提取研究

本实验以干燥厚补（Magnolia of ficinalis Rehd．et Wils．）皮为原料,用甲醇的水溶液来进行热浸渍提取法提取有效成分,而后用旋转蒸发仪浓缩,再用正己烷,二氯甲烷,乙酸乙酯,正丁醇依次萃取,分别得到正己烷,二氯甲烷,乙酸乙酯,正丁醇和水层五个层。将乙酸乙酯层浓缩后,用硅胶柱层析法进行分离纯化,并依据核磁共振确定其结构。结果表明：分离得到了较纯的起主要药用作用的木质素类化合物1：5,5’-二烯丙基-2,2’-联苯二酚（厚朴酚）和化合物2：5,3’-二烯丙基-2,4’-联苯二酚（和厚朴酚）。     

小麦酯酶的纯化研究

采用DEAE-52,Sephadex G-200柱层析法从辽春9号小麦面粉里提取分离纯化小麦酯酶,分别用二次蒸馏水、0.1～0.5 moL/J 的NaCl溶液进行梯度洗脱,最终确定,粗酶液经DEAE-52用二次蒸馏水、0.2 moL/L的Nacl溶液洗脱后的两组份为纯化组份.上述两组份经sephadex G-200用0.2mol/L的NaCl溶液洗脱后的3组份中第1组份分别为纯化组份,本法第1组份纯化倍数为4.9771倍,回收率为20.09%;第2组份纯化倍数为1.5276倍.回收率为8.55%.     

利用高速逆流色谱分离大黄活性成分

利用高速逆流色谱,采用加入酸碱的方法对传统中药大黄中的蒽醌类活性成分进行了分离研究.采用三氟乙酸做为保留酸,氨水作为洗脱碱,溶剂系统为正己烷/乙酸乙酯/甲醇/水(体积比为9∶1∶5∶5).对于分离产物做高效液相色谱分析,证明得到了大黄蒽醌的五种纯物质.     

乙酸乙酯制备实验的教学优化探索

乙酸乙酯制备实验中使用浓硫酸作催化剂由于存在不安全因素不宜于学生分组实验,通过实验探究和对照试验,建议改用1∶1硫酸溶液和石蕊三色环法进行实验,提高了实验操作的安全性、探究性与趣味性,进而优化了课堂教学.     

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.     

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.     

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。     

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     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.