共查询到20条相似文献，搜索用时 78 毫秒
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本文报导在 0 .0 5mol/L硼砂缓冲溶液中 ,以PVC膜碘离子电极直接电位法测定大米中碘的含量 ,方法灵敏度为 3× 10 - 7mol/L ,线性范围为 5× 10 - 7～ 10 - 3mol/L ,以该方法对蒸水沿岸地方的大米中的碘测定 ,分析表明 ,该地区中碘含量处在 0 .2～ 0 .6mg/kg范围 . 相似文献
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宁明远 《邵阳学院学报(社会科学版)》1997,(2)
在HA_c—N_aAc介质中,CPB对猛(11)催化高碘酸钾氧化甲基蓝的褪色反应有强烈的增敏作用,本文研究了影响其反应速度的最佳条件,建立了测定锰(11)的新催化光度法.方法线性范围为4×10~(-4)～8×10(-3)mg/L,检测下限为2.07×10~(-5)mg/L,可用于面粉和人尿中痕量猛的测定. 相似文献
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基于硫酸介质中,在溴化钾催化作用下,碘酸根氧化甲基橙褪色作用,据此建立了测定碘的动力学光度法.结果表明,最大吸收波长为507 nm时,碘酸钾浓度在0~1.6 mg/L内呈线性关系,表观摩尔吸收系数为9.17×104L.mol-1cm-1.方法用于加碘盐中碘(V)的测定,结果令人满意. 相似文献
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在HCl-NaAc(pH=0.90)酸性介质中,以钛催化过氧化氢氧化苯基荧光酮为指示反应,建立了一种催化动力学光度法测定痕量钛的新方法,并尝试用于测定大米、头发中的痕量钛(Ⅳ)。结果表明,在实验确定的最佳条件下,该方法的最低检出限为2.61×10-6 g/L,相对标准偏差为2.05%,测定的线性范围为(0.01～0.08)mg/L,结果令人满意。 相似文献
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在pH=4．5的HAc-NaAc介质中,痕量硫氰酸根能阻抑以2,2’-联吡啶为活化剂,阴离子表面活性剂十二炕基苯磺酸钠 (SDBS)为增溶剂,银催化过硫酸钾氧化天青(Ⅱ)的褪色反应,据此建立测定痕量硫氰酸根的阻抑催化动力学光度分析方法．该法检测限为2．0×10-2mg／L;线性范围为0．02-0．20mg／L.用于吸烟者和不吸烟者尿液中痕量硫氰酸根测定,结果满意． 相似文献
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通过对采用电感耦合等离子体发射光谱法测定摩托车催化转化器中贵金属铂钯铑含量的不确定度进行系统的分析,通过建立数学模型和分析不确定度的引入来源来研究其测定过程中的不确定度.结果表明:铂的含量为2. 005 9 mg/L,钯的含量为4. 067 3 mg/L,铑的含量为1. 956 2 mg/L,铂的不确定度为0. 056 8mg/L,钯的不确定度为0. 076 6mg/L,铑的不确定度为0. 058 7 mg/L,其中工作曲线的回归的不确定度分量对总的合成扩展不确定度的贡献是最大的. 相似文献
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《大连大学学报》2017,(6):55-60
用循环伏安法研究了玛卡中腺嘌呤在邻苯二胺/β-环糊精/银-碳纳米管修饰电极上的电化学行为。依次用邻苯二胺、β-环糊精、银-碳纳米管修饰电极,结果发现用银离子浓度为0.1 mg/m L,碳纳米管7 mg修饰过的电极催化效果最好。使用该修饰电极考察了腺嘌呤的电化学行为,发现在p H=7的PBS缓冲液中,腺嘌呤在修饰电极上的电化学响应较好,产生明显的氧化峰。该氧化峰电流与腺嘌呤在浓度为0.2 mg/m L到1.0 mg/m L范围内呈良好的线性关系,依此建立了玛卡中腺嘌呤含量的测定法。该方法灵敏、简便、重现性比较好,应用此方法能够准确的测定玛卡中腺嘌呤的含量。 相似文献
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王华芳 《三门峡职业技术学院学报》2013,(4):117-119
在0.025mol/L盐酸介质中,利用硒催化溴酸钾氧化甲基橙褪色的反应,建立了测定食品中硒的催化光度法.线性回归方程为Log（A0/A）＝0.0207C＋0.0106,RSD为0.60％,加标回收率为96.60％-98.20％,测定结果满意／ 相似文献
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在醋酸钠体系中,以α-α联吡啶为活化剂,用镍催化过硫酸钾氧化二氯荧光素,建立了测量海产品中的痕量镍催化动力学荧光法的分析方法.实验相关系数R=0.993 23,线性范围为0.5～5μg/L,相对标准偏差为2.94%,检出限为3.7×10-6μg/L.用该方法测定文蛤汁中的镍含量,结果令人满意. 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