共查询到20条相似文献，搜索用时 62 毫秒
1.
钙与邻甲酚酞在pH=11的碱性缓冲溶液中迅速形成紫色的络合物,于575 nm处具有最大吸收波长,加入8-羟基喹啉以掩蔽镁离子的干扰后测定钙的吸光度,摩尔吸光系数为2.14×104L.mol-1.cm-1.该法的最佳条件给予测定,收到良好的效果,回收率达99.1%.此方法可应用于食品以及生物样品中钙[1]的连续测定,简便、快速,结果令人满意. 相似文献
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研究了乙二醛双缩（2-羟基苯胺)与钙离子的显色反应．在PH值12～13范围内，该试剂与Ca反应生成紫红色配合物，无需萃取，在乙醉存在下，性质稳定．方法检出限为0．05μg／ml，线性范围为0．10～1．5μg／ml．此方法用于检测补钙药品、保健品中钙含量，快速、简便． 相似文献
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本文应用二甲酚橙分光光度法测定植株中钙、镁.样品首先采用H_2SO_4-H_2O_2-HCLO_4法进行快速消化,二甲酚橙在PHl0.8NH_4OH-NH_4CL缓冲液中与钙、镁配合,用EGTA.8羟基喹啉、硫代乙醇酸、三乙醇胺等掩蔽剂,详细研究了在各种实验条件下对钙、镁测定的影响与干扰.最终在自动分析中使用二甲酚橙分光光度法测定植株中的钙、镁、磷、钾. 相似文献
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确定分光光度法测定酸奶中钙含量的最佳操作条件.在pH值为10.8的NH3-NH4Cl缓冲溶液介质中,在澳化十六烷基吡啶(CPB)的作用下,Ca2+与二甲酚橙(XO)生成蓝色配合物,最大吸收波长为620nm,表观摩尔吸光系数为6.7×104L·mol-1·cm-1,Ca2+含量0～15μg/25mL.范围内符合比尔定律,相对标准偏差≤3.1%.加标回收率为96%～101.6%.方法具有灵敏度高,准确度好、体系稳定、试剂和仪器廉价、操作简便快速等优点. 相似文献
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在硫酸介质中 ,IO3- 氧化I- 产生 3倍摩尔量I3- ,而I3- 在紫外光区的 2 88nm具有最大吸收 ,ε2 88=1 .3× 1 0 5L·mol- 1 ·cm- 1 ,具有很高的灵敏度。碘的浓度在 0——— 6 0ug/1 0 0ml范围内符合比耳定律 ,方法简便快速、选择性好、灵敏度高 ,用于测定加碘食盐中碘的含量 ,结果满意 相似文献
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在钙、镁含量及水的总硬度测定实验中,研究了钙离子含量测定的主要影响因素及其消除方法.通过实验,论证了改进后的方法的有效性和实用性.采用本方法测定标准溶液及样品溶液中钙离子含量均获得满意结果. 相似文献
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本文通过实验首次建立了用火焰原子吸收分光光度法测定试剂碳酸锶中质钙、镁含量的方法。 相似文献
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间接紫外吸光光度法测定水果中VC含量 总被引：1，自引：0，他引：1
用I3-间接紫外吸光光度法测定11种水果中的Vc含量,并进行了重复实验和回收实验.其结果：Vc含量在0-0.99mmol/kg之间;回收率在92.8%-100%之间.该方法准确度较好,且方法简便,灵敏度可达0.025mmol/kg,可用于新鲜水果中VC的快速、简易测定. 相似文献
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原子吸收法测定鸡蛋壳中的钙、铁、镁、钾 总被引：3，自引：0，他引：3
采用原子吸收分光光度法对鸡蛋壳中的钙、铁、镁、钾的含量进行了测定，确定了该法测定的仪器测定条件，溶液测定消干扰的最佳条件，利用标准曲线法对榈进行了实际分析，获得满意结果。 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
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. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
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. 相似文献
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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. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
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。 相似文献
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《海外英语》2007,(5):10-11
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? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
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. 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
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 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