共查询到20条相似文献，搜索用时 78 毫秒
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目的:为充分利用大头艾纳香植物资源,避免资源的浪费,探讨大头艾纳香提取物中总黄酮的提取工艺.方法:采用超声波提取法从大头艾纳香中提取总黄酮类物质,通过正交与单因素实验,确定了大头艾纳香中总黄酮类物质提取的最佳工艺.结果:通过正交与单因素实验得到的工艺最佳条件是:浓度为65%乙醇,固液比为l:20,超声波时间30min,总提取3次,浸泡24h.在这种条件下,提取率最高,总黄酮得率可达4.417%.结论:这种提取工艺重现性好,简单可行,对工艺进一步的开发有很好的参考价值. 相似文献
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李天佑 《河北北方学院学报(医学版)》1990,(1)
近年来,利用光谱分析对中草药中无机元素的研究已十分广泛。中草药中的元素含量,由于其种类、品种、产地、采摘期、部位、优劣等情况不同,以致元素的种类和含量都有较明显的差异。我们利用原子吸收光谱测定了三七、天麻等二十二种中草药中八种微量元素的含量,并对其结果进行了分析。 相似文献
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以艾纳香幼茎段为外植体,研究激素对艾纳香诱导愈伤组织、继代增殖和生根的影响,建立了艾纳香试管苗快繁体系,并优化获得其最佳增殖初代培养基为MS+ 6-BA 2.0 mg/L;最佳增殖继代培养基为MS+6-BA 2.5 mg/L+NAA 0.3 mg/L;最佳的生根培养基为1/2 MS+ NAA 0.5mg/L;生根苗移栽于泥炭土与珍珠岩比为3∶1的混合营养杯中,成活率可达92.16％. 相似文献
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王德堂 《荆门职业技术学院学报》2013,(2):13-16
目的:建立拐枣中多种金属元素(Fe、Zn、Cu、Mn、Ca、K、Na、Mg、Cr、Pb)的含量测定方法。方法:以HNO3-HClO4(4∶1,V/V)为消化液,在常压微沸条件下对样品进行消化,采用火焰原子吸收光谱法进行拐枣中金属元素的含量测定。结果:拐枣中含有丰富的人体所需微量元素,含量顺序为Ca>K>Mg>Na>Mn>Fe>Zn>Cu,其中Ca、K、Mg和Na含量较高,而Mn、Fe、Zn和Cu较低,未检出Cr和Pb。方法的回收率为95.2%~102.3%,RSD小于1.5%,具有良好的准确度与精密度,可用于拐枣微量元素的同时测定。结论:该方法简便、快捷、准确,可用于拐枣中金属元素的测定。 相似文献
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近年来,废电脑及其配件中的金属材料的回收利用越来越受到人们的重视.报废电脑主板中含有大量的贵金属和贱金属元素.利用ICP-AES法对样品中的金属元素进行定性分析,用容量分析法测定了常量元素的含量,用火焰原子吸收法测定了微量元素的含量.讨论了基体元素对测定的影响,并做了回收实验. 相似文献
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《实验室研究与探索》2016,(11):44-46
通过实验,构建了采用ICP-OES测定铝渣中Al、Mn、Fe、Zn等17种金属元素的分析方法。铝渣样品经消解后,直接用ICP-OES测定,研究了影响测定的各种因素,确定了仪器的最佳工作参数,选择了合适的分析谱线。结果表明:铝渣消解液中17种金属元素的检出限较低,线性关系良好,R2≥0.999 9,RSD≤3.09%,回收率为87.50%~104.00%。 相似文献
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目的:测定山丹黄参中金属元素Mg、Ca、Fe、Cu、Zn、Pb的含量.方法:采用浓硝酸—高氯酸(V∶V=4∶1)常压微沸条件下消解黄参样品,应用火焰原子吸收法(FAAS)测定黄参中的金属元素Mg、Ca、Fe、Cu、Zn、Pb的含量,研究了测定不同元素的仪器最佳工作条件,并作了测定方法的准确性和精密度考察.结果:山丹黄参中Mg、Ca、Fe、Cu、Zn、Pb的含量分别为1932.8、3272.1、687.6、7.3、17.1μg.g-1,Pb未检出.方法的加标回收率为97.50%～102.16%,相对标准偏差(n=9)为0.21%～1.46%.结论:测定方法简单易行,方便快捷,结果可靠. 相似文献
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探索了石油催化裂解催化剂中多种的金属元素含量用ICP-AES法同时快速测定的条件、再现性、回收率,并与AAS法进行分析比较.方法操作简便、准确可靠、回收率高和重复性好.方法测定各元素呈良好线性关系,相关系数为0.9991～1.0000,回收率在100 10%之间,RSD 2.0%,检出限为0.4～6.0 μg/L. 相似文献
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为研究木香薷中人体必需的宏量金属元素含量状况,用微波消解法消解样品,用电感耦合等离子体-原子发射光谱法（ICP-AES）测定了木香薷叶、茎、花序样品中4种宏量金属元素（Ca、K、Mg、Na）的含量.结果表明：各测试元素校准曲线的相关系数均为0.999 8~0.999 9,显示其良好的线性;测定的RSD值均在0.36%～2.22%之间,显示了较高的测定精密度;木香薷叶、茎、花序三个部位中各元素含量相比,花序中的K与Na含量最高,分别为19.98 g/kg与0.27 g/kg,而叶中是Ca与Mg的含量最高,分别为22.33 g/kg与2.80 g/kg,茎中Ca、K与Mg的含量均居中,Na的含量最低,仅为0.09 g/kg.木香薷叶、茎、花序中4种人体必需的宏量金属元素含量丰富,但种类和数量因部位不同而异.应分不同部位对木香薷进行开发利用较为合理. 相似文献
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《海外英语》2007,(4):36
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. 相似文献
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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. 相似文献
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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. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Rajesh Kanoi 《海外英语》2007,(1):52
Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer. 相似文献
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正A One day a pig went to the stable(马棚)to see his good friend,an oldhorse,and was going to stay there forthenight.Night came and it was time forsleep.The pig went into the straw heap(稻草堆)and lay comfortably.A longtime passed,but the horse was stillstanding there and did not move.Thepig asked the horse why he did not go tosleep."Standing like this is the begin-ning ofsleeping,"answered the horse. 相似文献
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《今日中学生》2014,(9)
正1.Any fool can count the seeds in an apple.Only God can count all the apples in one seed.2.Happy families are all alike;every unhappy family is unhappy in its own way.3.Memories are the key not to the past,but to the future.4.Sometimes in the dark you see what you want to see.5.There is a great difference between 相似文献
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《重庆大学学报(英文版)》2014,(2)
正Scope and Policy The Journal of Chongqing University-English Edition(JCQU-E)is a peerreviewed journal publishing research articles in multiple disciplines of science and technology,covering civil and environmental engineering,chemical engineering,biotechnology,mechanical and electrical engineering,computer and data processing,mining,metallurgy,materials science,and interdisciplines thereof. 相似文献