石墨炉原子发射法测定饮料中的铝

石墨炉原子发射法(GFAES)是近年来发展起来的一种新的分析方法,该法对某些易激发元素(如K、Na、Ba、Al等)的测定灵敏度和稳定性皆优于石墨炉原子吸收法(GFAAS).本文在非火焰原子吸收装置上,对铝的GFAES法测定进行了较详细的研究,并通过测定不同包装的同类饮料中铝的含量,考察了方法的可靠性和精度,结果发现,该法完全可用于饮料中微量铝的测定.当被测溶液中铝的含量在0.00～0.25ppm时,铝的发射强度与浓度呈线性关系.加入回收试验表明,方法的回收率达96.0%～102.0%,对饮料中常见的各种成份进行干扰试验,发现100倍的K~+、Na~+、Ca~(++)、Mg~(++)、CO_3~-和50倍的柠檬酸,苯甲酸等不干扰铝的测定.     

原子荧光法与石墨炉原子吸收法测定水中砷含量的比较

本文探讨了氢化物原子荧光法与石墨炉原子吸收法在测定水中砷的含量方面的不同仪器性能.氢化物原子荧光法与石墨炉原子吸收法的检出限分别为0.043μg/L和2.20μg/L,精密度分别为1.37%、1.12%和2.24%、1.20.回收率分别为97.4～102.6%和95.3～103.0%.在水中砷的测定方面,氢化物原子荧光法要优于石墨炉原子吸收法,是一种值得推广的方法.     

石墨炉原子吸收法测定尿锑

采集锑接触作业人员尿样,以铜作为基体改进剂,用原子吸收分光光度计(石墨炉)测定尿的锑含量.结果建立了尿中锑的石墨炉原子吸收测定法.该方法线性范围为0～100μg/L,最低检出浓度为1.75ng/ml,回收率为101.0%～102.8%,相对标准偏差2.2%.该方法的线性好,精密度和准确度好,对于锑接触者的尿中锑含量测定明显高于非接触者.     

用原子吸收光谱法测定催化剂中的铂

建立了利用石墨炉原子吸收光谱法测定催化剂中铂含量的方法。在标准溶液和试样溶液中加入铜离子,可以消除其他离子的干扰,并且提高测定铂的灵敏度。实验表明,高浓度的铝对测定结果有影响,而酸度的影响很小。在一定的浓度下,Fe3+,Ni2+等7种干扰离子对测定结果的影响很小。该方法的检出限为0.044mg/L,加标回收率为99%～105%,相对标准偏差在0.73%左右。     

流动注射化学发光检测血清和头发中的铬

建立了一个基于鲁米诺 -H2 O2 -Cr(Ⅲ )反应的流动注射化学发光检测生物样品中铬的系统 .详细探讨了测定生物样品中铬含量的最佳条件及消除铁和钴干扰的问题 ,并成功地用于血清和头发中微量铬的测定 .样品测定的相对标准偏差小于 11% .回收率介于 90 %～ 10 5 %之间 .所得结果与石墨炉原子吸收法基本一致 .     

石墨炉原子吸收光谱法测定膨松剂中微量铝的质量浓度

目的:建立石墨炉法测定膨松剂中微量铝的方法.方法:用湿法消解和微波消解法消解样品,在257.4nm共振线,应用石墨炉原子吸收光谱法测定膨松剂中痕量铝.结果:湿法消解和微波消解法均适用于石墨炉原子吸收光谱法测定铝的质量浓度,本方法的定量限(LOQ):22.3μg/L,线性范围是:6.0~200μg/L,加标回收实验的回收率92%~108%.结论:该方法准确、可靠,灵敏度好,可满足膨松剂中微量铝的测定.     

抗坏血酸基体改进剂石墨炉原子吸收法测定饮用水中的锡

该文探讨用石墨炉原子吸收法测定饮用水中的锡的实验方法,样品采用硝酸酸化后,以抗坏血酸作为基体改进剂,塞曼扣背景,石墨炉原子吸收法进行测定。锡浓度在0～100μg/L范围内线性良好,相关系数为0.9995;该方法检出限为0.70μg/L,回收率为83.9%～97.2%。该方法具有快速、准确、灵敏度高等优点,适用于饮用水中锡的测定。     

冠醚交联壳聚糖在砷形态分析中的应用

研究二苯并18-冠-6冠醚交联壳聚糖对砷的吸附行为,建立了石墨炉原子吸收法测定环境水中痕量砷的形态分析方法,探讨了最佳分析条件.该法用于分析实际环境水样富集倍数达50倍以上,用2 mL 0.40 g·L-1酒石酸洗脱可直接测定有机砷含量,用2 mL 4 mol·L-1 HCl洗脱可直接测定无机砷含量.该法用于环境水中超痕量砷的形态分析测定,回收率达94%～105%,检出限(3σ)为0.20 μg·L-1,相对标准偏差为2.6%～3.2%.     

石墨炉原子吸收光谱法测定眼镜框镀层中的镍含量

利用石墨炉原子吸收光谱法测定眼镜框镀层中的镍含量,经试验选用涂层石墨管进行测定可获得令人满意的试验结果,该法线性范围为0.1～30μg/L,检出限为0.5μg/l,RSD为10%.     

石墨炉原子吸收光谱法测定食品中铝

为了提高食品中铝的测定结果的准确度、灵敏度，本文试验了石墨炉原子吸收光谱测定方法；该法提高了分析速度，有满意的准确度、灵敏度，可替代比色法及火焰原子吸收光谱法测定铝。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-