超声波法提取草珊瑚中总三萜的工艺研究

目的 优选超声波法提取草珊瑚中总三萜类成分的最佳工艺.方法 采用正交试验设计方案优化草珊瑚中总三萜类成分的超声提取,本研究以熊果酸为标准样品,利用分光光度法测定草珊瑚中总三萜吸光度值.结果 经过正交实验得到从草珊瑚总三萜的最佳工艺为:以90%的乙醇为提取剂,料液比1:30,超声提取温度60℃,超声作用时间40min.结论 该实验确定的最佳提取工艺简便易行,灵敏度高和重现性好.     

超声波辅助提取苹果中总多糖的方法研究

研究了超声技术对苹果中总多糖提取效果的影响,并在单因素实验的基础上设计了正交实验,确定了超声提取苹果中总多糖的最佳提取工艺．最佳提取工艺为提取时间20min、料液比1／125、超声温度45℃、乙醇浓度50％。采用该条件苹果多糖提取率最高达到55％以上。     

超声波辅助鱼腥草总黄酮提取工艺研究

目的：通过正交实验确定超声波法提取鱼腥草总黄酮的最佳工艺。方法：本研究以鱼腥草总黄酮的提取量为考察指标,通过正交实验研究4个因素对提取量的影响。结果：经过正交实验得到从鱼腥草中提取总黄酮的最佳工艺为：以50％的乙醇为提取剂,超声作用时间20min,超声提取温度40℃,提取量为2．255mg·g^-1。结论：该实验确定的最佳提取工艺稳定性好且简便易行。     

超声提取山竹果皮总黄酮及抗氧化性研究

研究正交试验优化超声提取山竹果皮中的总黄酮工艺,并通过测定总黄酮的还原能力表征其抗氧化能力.实验中采用乙醇为提取剂,分别对超声时间,乙醇体积分数,料液比等进行单因素实验,选取3因素3水平进行正交试验提取总黄酮.结果表明,总黄酮最佳提取工艺条件为超声时间50 min,乙醇体积分数60%,料液比1:30,最佳提取工艺条件下总黄酮提取率为0.349%.用含不同浓度的总黄酮提取液进行还原能力测定实验,得出总黄酮浓度越大,其抗氧化性能也越强.     

香蜜果多糖提取工艺条件优化研究

本实验采用超声辅助法对香蜜果多糖提取工艺条件进行研究.以水为溶剂通过提取时间、料液比、超声功率、提取次数等单因素考察对多糖提取率的影响.通过正交试验优选出香蜜果多糖的提取工艺.结果显示,最佳工艺条件：提取温度90℃,超声功率500W,提取时间30min,物料比1：30.在此条件下,香蜜果多糖的提取率可达3.16%,与理论预测值3.50%的相对误差较小.实验结果具有一定的参考价值,为香蜜果有效成分的提取及资源的开发提供参考.     

云南松松塔中原儿茶酸提取工艺的研究

目的：优化云南松松塔中原儿茶酸的提取工艺。方法：以不同溶剂对云南松松塔中原儿茶酸的提取效率为指标,用高效液相色谱法进行含量测定,采用L9（3^4）正交设计试验以确定最佳提取工艺。结果：最佳提取工艺：以乙酸乙酯为提取溶剂,加入0.1 mol/L的HCl 3 mL,料液比为1∶40（mg/mL）,超声时间90 min,超声温度40℃。结论：优化后的提取工艺简单、稳定、提取率高。     

竹叶总黄酮提取工艺研究

探讨用醇提法提取竹叶中黄酮类成分的最佳工艺,为竹叶的开发利用提供理论依据。以竹叶为试材,以乙醇为溶剂,采用分光光度法对竹叶中的黄酮类化合物的含量进行测试。通过单因素实验研究乙醇浓度、料液比、提取温度、提取时间对总黄酮提取率的影响,再采用正交试验法优化提取总黄酮的最佳工艺条件。单因素实验和正交试验表明:影响黄酮提取率的因素主次顺序是:料液比>乙醇浓度>提取温度>提取时间。最佳实验条件为料液比1:20,60%的乙醇,60℃提取4h,竹叶中黄酮的含量为7.88mg.g-1。     

葡萄中提取白藜芦醇的工艺研究

采用超声波法提取葡萄皮和葡萄籽中的白藜芦醇,由正交试验获得葡萄皮中提取白藜芦醇的最佳工艺为：乙醇提取剂浓度60%,料液比1∶12,超声时间12min,60℃水浴时间30min,白藜芦醇提取率为0.014 9%.葡萄籽中提取白藜芦醇的最佳工艺为：乙醇提取剂浓度60%,料液比1∶14,超声时间5min,60℃水浴时间30min,白藜芦醇提取率为0.005 7%.在此条件下的提取工艺稳定性好且简便易行,实验结果还显示葡萄皮中白藜芦醇的含量高于葡萄籽中的含量.     

基于正交试验优化重楼甾体皂甙超声提取工艺

以滇重楼的根茎为实验材料,重楼甾体总皂甙的提取率为评价指标,运用L16(45)正交试验,考察了皂甙浸出过程中的浸泡时间、乙醇浓度、超声剂量、粗粉质量与浸泡用乙醇体积之比等四个因素在四个水平下的工艺过程,筛选出了最佳提取工艺。实验结果表明,粗粉(40目)用30%的乙醇溶液浸泡36h后,超声30min,粗粉质量与(浸泡)乙醇的体积比1:15为最佳提取条件,重楼甾体总皂甙的提取率为9.50%。     

观赏金银花中绿原酸的超声提取研究

以观赏金银花为原料,利用超声波强化提取绿原酸化合物.在单因素试验的基础上,采用正交试验法,考察了超声时间、料液比、乙醇浓度、超声温度对绿原酸提取率的影响,确定最佳的提取工艺.结果表明:超声波提取观赏金银花中绿原酸的最佳工艺条件为乙醇浓度60%,料液比1∶20,超声温度70℃,超声时间40 min.在上述最佳条件下,绿原酸的提取量为36.72 mg/g.     

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.