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1.
在pH =5 0 0的HAc NaAc介质中 ,溴邻苯三酚红 (简称BPR)在汞电极上产生 2个还原峰 ,峰电位分别为- 0 95V和 - 1 0 3V (vs SCE) .加入稀土离子时 ,2峰都降低 ,并且在 - 1 0 3V处的峰电流的降低与加入稀土离子的浓度在 9× 10 - 8~ 1× 10 - 5mol/L范围内呈线性关系 ,检测下限达到 5 8× 10 - 8mol/L .该波可成功地用于微量稀土的测定 .通过对电极反应机理的研究 ,可以确定该体系是一个反应物强吸附、配体 2电子还原的准可逆过程  相似文献   

2.
吸附伏安法同时测定中草药中痕量的镍和钴   总被引:2,自引:0,他引:2  
提出一种有效的测定痕量镍和钻的吸附伏安法。利用悬汞电极作为工作电极,在0.005mol/L NH_3~0.06 mol/L NH_4Cl—3.0×10~(-6)mol/L锌试剂的最佳底液中,测定镍和钴的线性范围分别为1×10~(-10)~8×10~(-8)mol/L和1×10~(-10)~1×10~(-7)mol/L,检测下限均为5×10~(-11)mol/L。在工作中探讨了镍、钻和锌试剂配合物的吸附伏安行为及其在电极表面上的电化学反应机理。研究证明,该方法灵敏、可靠、省时,特别适用于中草药中痕量镍和钴的定量分析。  相似文献   

3.
选择5 种大孔吸附树脂(LSA20、21、30、40和 Diaon HP-20) 分离提取唐松草(Thalictrum simplex var. brevipes Hara) 中的总皂苷,考察大孔吸附树脂对唐松草总皂苷的吸附能力.结果表明Diaon HP-20的吸附效果最好,静态吸附容量达163.2×10-3 g/mL,动态吸附容量达102.5×10-3 g/mL.  相似文献   

4.
湍流时动能校正系数α的计算   总被引:1,自引:0,他引:1  
<正> 湍流时动能校正系数α可以用下式计算:α=(n+1)~3(n+2)~3/[4(3n+1)(3n+2)]运用此式可以很方便地求出不同n值时(或不同Re值时)α的数值。例如:当4×10~43.3×10~6时,n=1/10,α=1.031。  相似文献   

5.
本文研究了温度为77K时,压力为6×10~(-6)~5×10~(-8)乇,总量为W≤7×10~(-7)克的氩在1.0克椰子活性炭上的吸附特征、吸附动力学方程和吸附类型。为捕集真空状态下的微量氩提供了实验依据,为定量分析痕量氩建立了新方法。  相似文献   

6.
本文合成并测定了{MoOS_3Cu_3(PPh_3)C1}的晶体结构,簇合物属正交晶系,空间群为P_(212121)晶胞参数:a=12.833(5)×10~(-10)m,b=17.552(5)×10~(-10)m,c=22.778(7)×10~(-10)m;Z=4。结构用直接法解出,经最小二乘法修正,偏离因子R=0.069.  相似文献   

7.
4-氨基吡啶树脂对锌的吸附及解吸性能的研究   总被引:2,自引:0,他引:2  
研究了4-氨基吡啶树脂吸附锌的行为,结果表明在pH=2.63的HAc-NaAc体系中,树脂对锌(Ⅱ)有较好的吸附,其静态饱和吸附容量为58.4mg/g树脂,表观速率常数k298=3.42×10-5s-1,用pH=1-4的不同浓度盐酸洗脱,洗脱率均达100%。  相似文献   

8.
提出了吸附溶出催化伏安法测定痕量锗的方法。该方法最佳体系为0.15 mol/L KCl+1.0×10~(-3) mol/L 3,4-二羟基苯甲醛(DHB)+2.0×10~(-3)mol/L EDTA+3.0×10~(-3)mol/L V(Ⅳ),pH2.15。其线性范围为1.2×10~(-10)~6.O×10~(-8)mol/L,最低检出浓度为3.6×10~(-11)mol/L Ge(Ⅳ)。  相似文献   

9.
配合离子交换法吸附钽(Ⅴ)的性能及动力学研究   总被引:3,自引:0,他引:3  
本文研究了D-301大孔阴离子交换树脂从草酸水溶液中吸附钽草酸配合物的性能和动力学.实验结果表明,在[(NH_4)_2C_2O_4]=0.1267mol/L,[K_2S_2O_8]=0.0236mol/L,[Ta]=7.8×10~(-5)mol/L,pH=2.5~3.5条件下,钽的吸附率有一最大值.测得Freundlish常数k=2.14,吸附速度常数k_(30)°c=2.0×10~(-4)Sec~(-1),吸附活化能Ea=35.3kJ/mol,钽的饱和吸附容量C_(Ta)=168mg/g干树脂.  相似文献   

10.
本文报道了氯型大孔强碱型阴离子交换树脂吸附银(Ⅰ)和钯(Ⅱ)的性能和机理,以及分离Pd-~(111)Ag的最佳条件。通过综合考虑参与离子交换的[AgCl_4]~(3-)和[PdCl_4]~(2-)在柱色谱上的分离系数和理论塔极数,选择了6mol/l HCl为洗脱液,产品~(111)Ag收率95%,Pd杂质含量小于3×10~(-5)%。本方法在分离效果和操作方便性上均比文献已有报导的从堆照钯中分离无载体~(111)Ag的阴离子交换分离法有所提高。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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。  相似文献   

14.
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.  相似文献   

15.
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-  相似文献   

16.
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-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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