乌药叶黄酮类化合物的初步分析

对乌药叶中黄酮类化合物的含量进行了测定,并对其成分进行了定性分析。结果表明,乌药叶中黄酮类化合物的含量为2.1％,叶片中可能主要含有黄酮醇类化合物。     

九香虫黄酮类化合物的提取及含量测定

以70%乙醇为溶剂,采用索氏提取仪提取九香虫中黄酮类化合物,用分光光度法测定含量.结果测得样品中总黄酮的含量为1 122mg/100g,平均回收率为98.8%.九香虫中含有一定量的黄酮类化合物,但含量较少.     

石榴叶中总黄酮含量的测定

用分光光度法对石榴叶中总黄酮含量进行了初步测定,结果表明,石榴叶中黄酮类物质含量非常高,可达3.59mg/g,这将为开发利用石榴叶资源提供依据.     

黄柏中黄酮类化合物的提取及其抗氧化性分析

采用超声波法提取黄柏中的黄酮类化合物,并用紫外分光光度法测定了黄酮含量.本方法的回收率为95.3%~101.1%,变异系数小于0.35%.用流动注射化学发光分析法测定了黄柏的抗氧化性,结果表明黄柏中所含的黄酮类化合物具有较强的抗氧化性.     

犁头草中化学成分及总黄酮含量的研究

目的:研究犁头草中的化学成分,测定犁头草中总黄酮的含量.方法:以鉴别法对犁头草提取物中的化学成分进行定性,以芦丁为对照品,采用紫外分光光度法在274nm处测定犁头草中总黄酮类化合物的含量.结果:犁头草提取物中含有大量黄酮,总黄嗣含量为15.5%,芦丁对照品在0.800～16μg/mL浓度范围内线性良好,R=0.9997,总黄酮平均回收率为99.5%,RSD为1.76%.结论:该研究首次报道了犁头草中的化学成分及总黄酮含量的测定,此方法仪器要求低、灵敏度高,操作简便、快速,结果准确,可作为犁头草总黄酮研究及含量测定的方法.     

山楂片中总黄酮含量的测定

本文根据黄酮类化合物与铝盐反应可生成黄色络合物(λmax=415nm)其颜色深浅与溶液的浓度在一定范围内成线性关系的特点,采用分光光度法测定山楂片中的黄酮含量.     

不同生境甜槠黄酮类化合物含量及成分分析

运用分光光度法测定了来自浙江台州境内天台山不同生境的甜槠黄酮类化合物的含量并对其成分进行了聚酰胺薄层层析分析。结果表明,甜槠不同生境的叶片黄酮类化合物以冠层生境含量最高,灌丛生境次之,林下生境含量最低;林下生境的黄酮类化合物成分最少,而冠层生境的成分最多。     

干豌豆中皂苷与黄酮类化合物含量研究

皂苷和黄酮类化合物广泛存在于植物体内,国内外对二者的研究十分活跃.研究表明,皂苷和黄酮类化合物均具有较强的生理活性及多种多样的药理功能.为了研究豌豆中的皂苷和黄酮类化合物及其各自的含量,本研究采用水提皂苷做定性实验研究来鉴别豌豆中皂苷的类别,并利用热乙醇冷却的方法对皂苷进行提取、分离和测定;还进一步利用碱溶酸沉法对皂苷滤液中的黄酮类化合物进行提取和测定.研究结果表明,豌豆中皂苷类型为三萜皂苷,其含量为碗豆干粉的3.86%,黄酮类化合物含量为碗豆干粉的2.11%.     

芹菜不同部位黄酮含量与抗氧化性量效关系的分析

对芹菜不同部位黄酮化合物进行提取,采用光谱法对其含量进行分析.测定波长为510 nm,线性范围为0.2557～0.7670 mg/mL,方法的回收率为101.5％～104.6％,变异系数小于0.27％.用流动注射化学发光法分析了芹菜不同部位的抗氧化性,实验结果表明芹菜中含有丰富的黄酮类化合物.芹菜不同部位中黄酮化合物含量不同,芹菜叶中黄酮含量最高,芹菜根中黄酮含量次之,而芹菜茎中黄酮含量最低.芹菜具有较强的抗氧化性,芹菜不同部位抗氧化性不同,芹菜叶的抗氧化性最强,芹菜根次之,而芹菜茎中抗氧化性最低.芹菜不同部位即根、茎、叶中黄酮类化合物含量与抗氧化性增加趋势相同.芹菜根、茎、叶的黄酮含量与抗氧化性呈现明显的量效关系.     

桃红四物汤水提液中总酚酸含量测定

目的:测定桃红四物汤水提液中总酚酸(TPA)的含量.方法:总酚酸的含量测定采用可见分光光度法,以没食子酸为对照品,0.6%FeCl3～0.9%K3\(1∶0.9)混合液为显色剂,在720nm波长处进行测定.结果:分光光度法测定总酚酸在所试浓度范围内(0.1756～0.8780μg/mL)线性关系良好,r=0.9968.总酚酸的平均回收率为99.96%,RSD为4.1%. 结论:本法简单快捷,重现性好,可作为桃红四物汤中总酚酸的质控方法.     

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?     

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.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.