湿法消解-火焰原子吸收光谱法测定两种茶叶中锌、铁、铜、锰的含量

本实验采用湿法消解处理样品、火焰原子吸收光谱法测定样品溶液中的四种微量元素.结果:北川绿茶中Zn、Fe、Cu、Mn的含量分别为10.60μg/g、66.55μg/g、8.80μg/g、145.8μg/g,北川茉莉花茶中Zn、Fe、Cu、Mn的含量分别为11.40μg/g、64.35μg/g、9.20μg/g、149.2μg/g.两种茶叶的相对标准偏差(RSD)均小于1.0%,线性范围在0.00²0.00μg·m L-1,平均回收率在95.5%20.00μg·m L-1,平均回收率在95.5%¹01.0%.该方法简单、快速、准确性高用于两种茶中四种微量元素的测定,结果令人满意.     

原子吸收法测定当归补血汤等方剂中常见微量元素

为了研究经典方剂中微量元素含量与疗效之间的关系,用原子吸收光谱法对当归补血汤、归脾汤、六味地黄汤3个方剂中的Cu、Zn、Fe、Mn、Co等5种微量元素进行了测定.结果表明:当归补血汤中的Zn、Fe、Mn含量分别为36.75μg/g、500.25μg/g和28.31μg/g,均远高于其他两种方剂.从微量元素的角度来看,当归补血汤的补血效果应该更好.     

石墨炉原子吸收直接法测定海水铅的研究

试验表明用石墨炉原子吸收光谱法直接测定海水Pb时,抗坏血酸—HNO_3是消除海水基体干扰的有效基体改进剂。样品从石墨管壁原子化,不同商标的热解涂层石墨管效果不一。分析结果通过“质控海水”和“极谱分析法”的验证,结果是满意的,回收率在95～99％范围。对含Pb lμg/L以内的海水可直接测定。     

石墨炉原子吸收直接法测定海水河水钴

本文提出了一种简便、快速直接测定海水Co的石墨炉原子吸收光谱方法。研究了几种不同的有机基体改进剂及石墨炉升温程序对消除基体干扰的效果。管壁原子化、酒石酸为基体改进剂、积分吸收测量、一次进样20μl(或多次进样以提高灵敏度)以及严格控制狭缝宽度在0.4nm可以获得最佳分析结果。海水Co的检测限(3σ)为0.1μgL~(-1),特征质量mo为4.6pg/0.0044A.S。11个海水样品及4个河水样品的平均回收率为98％,平均相对标准偏差为4.6％。     

葡萄果肉和葡萄皮有机酸含量的高效液相法测定

采用Hibar column RT250mm×4.6mm,5μm色谱柱,以磷酸盐缓冲溶液(pH=2.5)为流动相,流速1mL/min,检测波长214nm,柱温30度.建立葡萄果肉和葡萄皮中富马酸、酒石酸、柠檬酸、苹果酸等有机酸的高效液相色谱分析方法.其中富马酸、酒石酸、柠檬酸和苹果酸的线性范围分别为0.1～100 mg/L、5～600 mg/L、15～1500 mg/L、10～1000 mg/L;回收率分别为119.3、89.2、99.4、101.6;检出限分别为0.000625mg/L、0.1 mg/L、0.2mg/L、0.1 mg/L.     

G市大学城管网末梢水中CHCl_3和CHBr_3含量的测定及煮沸时间对含量的影响

为了解G市大学城管网末梢水中CHCl_3和CHBr_3含量情况,并掌握煮沸去除CHCl_3和CHBr_3的最佳时间.实验采集G市大学城五所高校早、中、晚三个时点的管网末梢水,采用气相色谱法检测CHCl_3和CHBr_3的含量,考察了分析方法的线性关系、检出限、回收率和精密度.实验结果表明:在0μg·L^(-1)～16μg·L(-1)～16μg·L^(-1)内CHCl_3和CHBr_3浓度与峰面积呈良好的线性关系,直线方程分别为y=10011x+38和y=12037x+2158,相关系数均大于0.999;最低检出限分别为0.21μg·L(-1)内CHCl_3和CHBr_3浓度与峰面积呈良好的线性关系,直线方程分别为y=10011x+38和y=12037x+2158,相关系数均大于0.999;最低检出限分别为0.21μg·L^(-1)和0.22μg·L(-1)和0.22μg·L^(-1);回收率为94.5%～103.4%,精密度分别为1.17%～1.83%和1.07～2.74%.五所高校管网末梢水中CHCl_3和CHBr_3最高含量分别为(4.03SymbolqB@0.12)μg·L(-1);回收率为94.5%～103.4%,精密度分别为1.17%～1.83%和1.07～2.74%.五所高校管网末梢水中CHCl_3和CHBr_3最高含量分别为(4.03SymbolqB@0.12)μg·L^(-1)和(2.35SymbolqB@0.07)μg·L(-1)和(2.35SymbolqB@0.07)μg·L^(-1),最低含量分别为(1.94SymbolqB@0.05)μg·L(-1),最低含量分别为(1.94SymbolqB@0.05)μg·L^(-1)和(1.03SymbolqB@0.03)μg·L(-1)和(1.03SymbolqB@0.03)μg·L^(-1),含量均未超出国家标准限值;含量均呈现从早到晚逐渐降低的趋势,随煮沸时间增加,去除率逐渐增加,推荐将管网末梢水煮沸3 min后饮用.     

溴甲酚绿-高碘酸钾催化光度法测定痕量Mn（Ⅱ）

研究了在pH 4.1HAc—NaAc介质中,以氨三乙酸为活化剂,Mn（Ⅱ）催化高碘酸钾氧化溴甲酚绿褪色反应的条件及影响因素,建立了动力学光度法测定痕量Mn（Ⅱ）的新方法。方法的线性范围为0.4～12μg/L;检出限为0.12μg/L,对8μg/L Mn（Ⅱ）平行测定11次的相对标准偏差为0.09%。该催化反应的表观活化能为42.24kJ/mol,反应的表观速率常数为3.5×10^-4 s^-1。该方法具有较高的灵敏度和选择性,用于井水、自来水样品中锰含量的测定,结果令人满意。     

黄秋葵果皮与根的抗氧化活性比较

用体积分数为90%的乙醇溶液对黄秋葵果皮和根进行回流提取,以不同极性的溶剂进行萃取,测定提取物中总酚、总黄酮的含量及抗氧化活性.结果表明:黄秋葵果皮和根的EA层萃取物中,总酚含量分别为55.411、45.845 mg没食子酸/g,总黄酮含量分别为12.293、12.177 mg槲皮素/g,对应的DPPH自由基清除能力的EC50值分别为164.02、96.67μg/m L.还原能力测定结果表明,黄秋葵果皮和根在质量浓度1 000μg/m L时吸光度达到最大值,分别为0.328和0.156.相比较来说黄秋葵果皮具有更好的抗氧化活性.     

氢化物发生—原子荧光法同时测定绞股蓝中的痕量铋和砷

采用氢化物-原子荧光法测定绞股蓝中的痕量铋、砷,实验了酸介质和不同还原荆对测定的影响,考虑了金属离子的干扰.在最佳测定条件下,检出限分别为Bi:0.070μg/L、As:0.085 μg/L.线性范围分别为Bi:0.1～130μg/L、As:0～180μg/L,加标回收率在90.1%～109.4%之阃.结果表明本法具有快速、简便、准确等特点.     

微波消解氢化物发生原子荧光法同时测定农产品中砷和汞

建立了微波消解氢化物发生原子荧光光谱法测定农产品中砷、汞含量的方法。研究了硼氰化钾浓度、酸度、载气流量等条件对原子荧光强度的影响。在最佳的工作条件下,对砷和汞检测的线性范围分别为0.4090μg/L～4.090μg/L、0.2026μg/L～2.026μg/L,相关系数分别为0.9984、0.9965,砷和汞的检出限分别为0.084μg/L和0.022μg/L,相对标准偏差均小于7%,符合国际上对农产品安全质量检测的要求。     

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,     

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…     

胡主席在印度,我却在中国

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.     

STORIES

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.     

巧妙引语(英文)

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     

Information for Authors

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.