催化动力学光度法测定食品中痕量铁

本文研究了在硫酸介质中,痕量铁(Ⅲ)催化过氧化氢氧化茜素红而使其褪色的动力学条件,建立了测定痕量铁的新方法,其灵敏度为2.0×10-9g/mL,线性范围0—7μg/25 mL,用于水样、食品中痕量铁(Ⅲ)的测定,结果令人满意。     

多元校正线性回归法同时测定铁和锰的研究

基于铁(Ⅲ)和锰(Ⅱ)对高碘酸氧化罗丹明B褪色的催化作用及在不同反应条件下两者催化作用的差异，以反应条件作为化学计量学中的量测通道，应用多元校正线性回归法对铁(Ⅲ)和锰(Ⅱ)同时测定进行了研究，建立了流动注射催化光度法同时测定铁和锰的方法。在铁和锰浓度比为1：10—1：1的范围内，应用该法对其混合物进行测定，回收率分别为100．0％和111．7％：     

以表面活性剂为增敏剂光度法测微量铁

亚甲基蓝是一种高灵敏度显色剂，以十二烷基苯磺酸钠为表面活性剂，铁(Ⅲ)与邻二氮菲形成络合物后，在PH=4．5时，该络合物有最大吸收蜂λ=660nm，铁含量在O～40μg范围内符合比尔定律。选用660nm作为工作波长，可选择性地测定多样品中微量铁(Ⅲ)，方法灵敏，操作简便．     

离子色谱法中光度检测柱后衍生体系的研究

根据离子色谱法中柱后衍生光度检测的作用机理,可将其分为直接显色、置换显色和置换脱色3种类型。本文在此基础上提出用二甲酚橙、Cu—EDTA—PAN、铁(Ⅲ)—磺基水杨酸(Fe(Ⅲ)—Ssal)和铁(Ⅲ)—SCN 分别作为柱后衍生体系,在可见光区检测碱土、过渡、稀土、重金属离子及部分无机阴离子,取得良好的检测效果。文中对比考察了检测离子的范围、检测极限及有关规律性,可供选择柱后衍生体系时参考。     

三草酸合铁(Ⅲ)酸钾绿色合成与结构表征

以草酸钾与氯化铁为原料,通过室温固相SH反应合成了三草酸合铁(Ⅲ)酸钾配合物,用滴定分析、X射线单晶衍射、X射线粉末衍射、红外光谱、热分析等方法对其组成和结构进行了表征。实验结果表明:三草酸合铁(Ⅲ)酸钾的晶体结构属于单斜晶系,P2(1)/c空间群;草酸根中的氧原子与铁(Ⅲ)形成配位数为6的变形八面体配合物;在氮气气氛中的热分解过程分4步,最后的残余物为FeO和K_2CO_3。这些测试表征结果可为学生更好地完成实验提供重要的参考信息。     

双水相萃取法分离生活污水中重金属离子和机理研究

研究了生活污水中铅(Ⅱ)、铁(Ⅲ)、铬(Ⅲ)、锰(Ⅱ)等金属离子在聚乙二醇(PEG) -Na2SO4-邻苯二酚紫(PV)体系中的萃取行为.探讨了萃取酸度、萃取剂用量、硫酸铵浓度对金属离子萃取率的影响.实验结果表明,通过控制一定的条件,可以实现铬(Ⅲ)、铅(Ⅱ)与部分混合金属离子之间的萃取分离.     

Co(Ⅱ)-F(Ⅲ)-phen分光光度法测定钴

该文研究了铁(Ⅲ)-钴(Ⅱ)-邻菲罗啉体系的显色反应,pH=4.0时,铁(Ⅲ)、钴(Ⅱ)、邻菲罗啉间生成红色配合物,其吸光度稳定,在3小时内无显著变化。配合物的λ_(max)=510nm,ε_(510)=1.0×10~4L·mol~(-1)·cm~(-1),钴含量在0～8μg/mL范围内符合比耳定律。此方法的变异系数为0.55％。     

水果、药物或蔬菜中抗坏血酸的分光光度测定综合实验

依据抗坏血酸还原定量过量的铁(Ⅲ)产生铁(Ⅱ),新生的铁(Ⅱ)与邻菲罗啉形成红色配合物的原理,开发了综合性实验--水果、药物或蔬菜中抗坏血酸的分光光度测定,应用于无机及分析化学实验教学,并取得了良好的效果.     

混合胶束协同增效光度法测定陶瓷原料中铁

研究了聚乙烯醇(PVA)、溴化十六烷基三甲基铵(CTMAB)和Triton X-100组成的混合胶束对硫氰酸盐和结晶紫与铁(Ⅲ)显色反应的增敏、增稳作用,建立了光度法测定陶瓷原料中铁(Ⅲ)的新方法.结果表明:在0.5 mol/L H2SO4介质中,在混合表面活性剂的作用下,铁(Ⅲ)与结晶紫和硫氰酸盐形成红色的缔合物,λmax=482 nm,表观摩尔吸光系数为4.1×104 L?mol-1?cm-1.铁的质量浓度在0~2μg/mL范围内与吸光度呈良好的线性关系.显色反应有良好的选择性,主要共存离子均有较大的允许量,方法应用于陶瓷原料中铁的测定,相对标准偏差分别为1.6%和2.3%,加标平均回收率为103%~105%.     

双水杨醛邻苯二胺与Fe(Ⅲ)的显色反应研究及应用

研究了双水杨醛邻苯二胺(SALOPHEN)与Fe(Ⅲ)的显色反应，试验表明，在pH=2.21的氨基乙酸-盐酸缓冲介质中，在阴离子表面活性剂十二烷基磺酸钠(SDS)存在下，Fe(Ⅲ)与双水杨醛邻苯二胺(SALOPHEN)形成1：1稳定的棕色配合物。其最大吸收峰位于462nm处，表观摩尔吸光系数为4.1′104。铁浓度在0-4．5mg／ml范围内符合比尔定律。方法具有较高的灵敏度和选择性。应用于食品样品中微量铁的测定，结果满意。     

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?     

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.     

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.     

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.     

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.     

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.