铂饰品中Pt, Pd, Au, Ag, Cu, Ni, Zn, Fe的测定

试验研究建立了同一试料溶液连续、同时测定铂饰品中各成分的分析方法。主体Pt以氯铂酸铵称量法及火焰原子吸收光谱(FAAS)法或电感耦合等离子发射光谱(ICP-AES)法测定滤液中残留Pt进行补差而测定。主成分Pd,Au,Ag,Cu和焊料成分Ni,Zn,Fe以FAAS法或ICP-AES法测定。其方法回收率分别为:Pt99.9%~100%;Pd99.3%~99.7%;Au99.5%~l01.5%;Ag98.0%~100%;Cu97.7%~99.3%;Zn98.0%~99.0%;Ni94.0%~105%;Fe95.0%~99.0%。实际试样分析时,各成分质量分数之和一般在99.12%~l01.2%之间,接近于100%,间接说明方法的可靠性。本法适用于Pt-Pd二元体系和Pt-Pd-Au-Cu多元复杂体系的铂饰品的破坏分析,可用于校正X荧光光谱法无损检测铂饰品的分析结果。     

X射线荧光光谱法测定烧结矿中Fe,Al,Ca,Mg,Si,S,Mn,P

烧结矿是高炉冶炼的重要原料之一 ,准确快速分析烧结矿中主、次量元素 ,对于指导烧结矿及高炉生产具有重要意义。由于烧结矿日常分析元素较多 ,采用化学分析方法 ,分析时间长 ,手续繁琐。本文利用多道同步Ｘ射线荧光光谱仪 ,合理选择分析及制样条件 ,对烧结矿中主、次量元素进行分析。结果表明 :该法分析速度快、准确度高 ,完全满足日常分析的要求。1　实验部分1 1　仪器及工作条件Ｓｉｍｕｌｔｉｘ 1 1型Ｘ射线荧光光谱仪 (日本理学 ) ,盘式振动磨 (ＷＣ材质 ) ,5 0ｔ油压机。工作条件 :Ｘ光管 ( 4 0ｋＶ - 2 5ｍＡ) ,Ｐ1 0气体流量 2 5ｍ…     

FAAS法测定铝合金中Fe,Cu,Zn,Mn,Ni,Ca,Mg和Cr

铝合金的分析一般采用化学法、光谱法[1],部分元素的测定也有采用火焰原子吸收法的报导““,化学法操作繁琐,周期长,技术条件严格,而且所用的试剂量大．本文采用火焰原子吸收法连续测定了铝合金中铁、铜、锌、锰、镍、钙、镁和铬．方法操作简单、准确、稳定．1实验部分1．1主要仪器和试剂PE3030B原子吸收光谱仪．氯化钢溶液（lap／L）：称取259LaP。,溶于80rnL盐酸中,用去离子水稀释至250InL;铁、铜、锌、锰、镍、钙、镁、铬标准溶液：浓度均为IIDg／mL。仪器工作条件见表l．1．2分析步骤称取1．00009样品于250mL烧杯中,加人…     

电感耦合等离子体原子发射光谱法测定铁矿石中Si,Ca,Mg,Mn,Al,P,V,Ti

铁矿石中Si O2,CaO,MgO,MnO,Al2O3,P,V2O5,Ti O2,通常用分光光度法或容量法分别测定,方法繁琐费时。用电感耦合等离子体光谱仪测定铁矿石的主体成分,方便快捷,准确性好,无明显的化学干扰。通过研究对比,选择无明显干扰的两条或一条谱线,使选择的波长符合在同一溶液中能同时测定其它组分的要求;同时采用与试样组分相近的标准样品绘制工作曲线,用标准样品进行对照,ICP-AES法测定铁矿石中上述组分,结果令人满意。1实验部分1·1主要仪器及工作条件IRIS IntrepidⅡ型垂直全谱直读等离子光谱仪(美国Thermo公司):固体检测器(CID),波长…     

FAAS法测定磷矿粉中微量Fe,Co,Ni,Cu,Pb,Zn

用火焰原子吸收光谱法对新疆某地的磷矿粉中Fe ,Co ,Ni,Cu ,Pb ,Zn微量元素进行了分析测定 ,并探讨了酸度、干扰离子等对测定的影响。所拟方法快速、简便 ,分析结果十分满意     

X射线荧光光谱仪测定铝合金中Si,Mn,Fe,Cr,Ni,Ti,Cu

采用改造后的VXQ -15 0AX射线荧光光谱仪和日本岛津公司提供的数据软件 ,合理选择分析条件 ,对铝合金中Si,Mn ,Fe ,Cr,Ni,Ti,Cu元素进行测定 ,结果较为满意。     

ICP-AES法测定钼铁中Mo,Si,Cu,Sb,Sn

以电感耦合等离子体光谱法(ICP-AES)直接同时进行钼铁中基体元素Mo和微量杂质元素Si,Sb,Sn,Cu的测定。试验了元素的干扰情况,优化了仪器工作条件,采用钇内标校正与同步背景校正、K系数校正相结合的方法消除基体及试液进样的物理化学影响干扰。精密度、回收率、检出限、标准样品分析对照均取得了满意的结果。     

纯铜中铋,锑,砷,铁,镍,铅,锡,锌的光谱定量分析

本文介绍了一种光谱定量分析方法。该方法使用ＢＹＧ０１－１氧化铜光谱标准样品，对１－４号纯铜中铋、锑、砷、铁、镍、铅、锡、锌８个杂质元素进行定量分析。分析方法简单，测定结果与化学结果基本相符。方法的测定下限为３×１０￣（０６）。     

火焰原子吸收光谱法测定混合铜矿中Cu,Fe,Ni,Zn,Mg,K

用火焰原子吸收光谱法对新疆某地的混合铜矿进行分析测定,并探讨了酸度、干扰离子对测定结果的影响,取得了满意的结果。     

Effects of simple indoles, noradrenaline, nicotine, and tyramine on action potential and contractility of the isolated guinea-pig papillary muscle

1. Simultaneous recordings of both the transmembrane action potential and the contractions were made in isolated electrically driven papillary muscles of the guinea pig in order to compare the effects of 6-methoxyindole (6-MOI), 3-methylindole (3-MI) and 5-methylindole (5-MI) with those of noradrenaline (1.2 - 10(-6) M), nicotine (2 - 10(-5) M), and tyramine (5.8 - 10(-6) M). 2. Noradrenaline, nicotine, tyramine and 6-MOI (5.4 - 10(-4) M) enhanced the contractility whilst 3-MI (3.8 and 7.8 - 10(-4) M) and 5-MI (1.9 and 3.8 - 10(-4) M) had only irregular effects. The active compounds shortened and time-to-peak tension and increased the rate of relaxation. 3. The duration of the action potential was prolonged by noradrenaline, nicotine, and tyramine, but shortened by 3-MI, 5-MI, and 6-MOI. 4. The results showed that the effect of drugs on the action potential are not necessarily linked to those on contractility.     

Optimization and Calculation of TbCl3-ACl（A = Li, Na, K, Rb, Cs）Phase Diagrams

Thermodynamic information of the melts involvingrare earth halides and alkali halides plays an importantrole in the preparation of rare earth metals by moltensalt electrolysis and by metallothermic reduction. Theknowledge of thermodynamics of molten s…     

Thermodynamic Assessment of DyCl3-MCl （M= Na, K, Rb, Cs） Systems

Using the CALPHAD （Calculation of Phase Diagram） technique, the DyCl3-MCl （M = Na, K, Rb, Cs） systems were optimized and calculated. The modified quasi-chemical model in the pair approximation for short-range ordering was used to describe the Gibbs energies of the liquid phase in these systems. From the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized base on an interactive computer-assisted analysis. The optimized parameters and the experimental data were thermodynamically self-consistent. The optimized results were discussed.     

Thermodynamic optimization and calculation of phase diagrams of YbCl3-MCl (M=Na, K, Rb, Cs)

YbCl3-MCl (M = Na, K, Rb, Cs) systems were optimized and calculated using the CALPHAD (CALculation of PHAse Diagram) technique. The modified quasi-chemical model in the pair-approximation for short-range ordering was used to describe the Gibbs energies of liquid phase in the systems. On the basis of the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized and calculated through an interactive computer-assisted analysis. Furthermore, some reasonable discussions on the thermodynamic parameters for these strong interaction binary systems were carried out. The results showed that the optimized parameters and experimental data are thermodynamically self-consistent.     

Thermodynamic Optimization of TmCl3-ACl （A = Na, K, Rb, Cs）Phase Diagrams

As well known, molten salt electrolysis was wide ly used for the production of rare earth metals andtheir alloys. And, phase diagrams are the most impor tant data for fused electrolytes. Dealing with the bina ry phase diagrams relating to rar…     

Role of imidazoline receptors in the cardiovascular actions of moxonidine, rilmenidine and clonidine in conscious rabbits

The present study in conscious rabbits with intracisternal (i.c.) catheters sought to determine the relative contribution of the I1 subtype of imidazoline receptors (IR) and alpha 2 adrenoceptors to the hypotensive effects of rilmenidine, clonidine and moxonidine with an I1-IR/alpha 2 adrenoceptor antagonist efaroxan and a specific alpha 2 adrenoceptor antagonist 2-methoxyidazoxan (2-MI). The alpha 2 adrenoceptor antagonist effect of efaroxan was compared with 2-MI by performing cumulative dose-response curves in the presence of alpha-methyldopa (400 micrograms/kg i.c.). 2-MI was 5.6 times more potent than efaroxan at reversing 75% of the hypotension elicited by alpha-methyldopa (P < .025). This dose ratio was used to match doses of efaroxan and 2-MI for similar alpha 2 adrenoceptor blockade. The effects of efaroxan (4.1, 13, 41 micrograms/kg i.c.) and 2-MI (0.74, 2.3, 7.4 micrograms/kg i.c.) were investigated on a single i.c. dose of rilmenidine (12 micrograms/kg), clonidine (0.75 microgram/kg) and moxonidine (0.51 microgram/kg). These doses of the antihypertensive agents, which were determined from cumulative dose-response curves, produce 90% of the maximum hypotension. Efaroxan was more effective at reversing the hypotension induced by moxonidine and rilmenidine than was 2-MI (P < .01). These findings suggest that rilmenidine and moxonidine act predominantly via IR. By contrast, 2-MI was more effective at reversing the clonidine-induced hypotension than was efaroxan (P < .001), suggesting that clonidine acts mainly via alpha 2 adrenoceptors in conscious normotensive rabbits. Thus, a higher selectivity of the second generation agents moxonidine and rilmenidine for I1-IR over alpha 2 adrenoceptors, compared with the first generation agent clonidine, appears to be necessary for this effect to be manifested in their hypotensive actions.     

Somatic hypermutation of immunoglobulin genes is independent of the Bloom''s syndrome DNA helicase

The aim of these studies was to examine the effects of imidazoles on testosterone secretion and testicular interstitial fluid (TIF) formation through measurement of serum LH, serum testosterone, TIF testosterone, and TIF volumes. Imidazole, 1-methylimidazole, 4-methylimidazole (4-MI), and ketoconazole, an oral imidazole antifungal agent, caused dose-dependent decreases in testosterone secretion and TIF formation. Imidazole, 2-methylimidazole, and 4-MI decreased LH secretion. 4-MI decreased testosterone secretion 1-6 h after injection, increased testosterone at 8-16 h, decreased LH secretion at 4 h, decreased TIF volumes at 1-8 h, and slightly increased TIF volumes at 24 h. 4-MI blocked the stimulatory effects of hCG on testosterone secretion and prevented an expected increase in LH secretion after the 4-MI-induced decrease in testosterone secretion. 4-MI also reversed the effects of three other stimulants of testosterone secretion that presumably act through three different testicular regulatory systems: N-methyl-D,L-aspartate, an excitatory amino acid; NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor; and naltrexone, an opioid antagonist. These results support the hypothesis that imidazoles inhibit testicular function and male reproductive function through inhibition of testosterone secretion, TIF formation, and LH secretion regulatory systems.     

Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the CaO-Al2O3, Al2O3-SiO2, and CaO-Al2O3-SiO2 systems

All available thermodynamic and phase diagram data have been critically assessed for all phases in the CaO-Al₂O₃, Al₂O₃-SiO₂, and CaO-Al₂O₃-SiO₂ systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable data for the binary systems have been simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag and all solid phases as functions of composition and temperature. The modified quasichemical model was used for the slag. With these binary parameters and those from the optimization of the CaO-SiO₂ system reported previously, the quasichemical model was used to predict the thermodynamic properties of the ternary slag. Two additional small ternary parameters were required to reproduce the ternary phase diagram and ternary activity data to within experimental error limits. The calculated optimized phase diagram and thermodynamic properties are self-consistent and are the most reliable currently available estimates of the true values.     

Phase relations associated with the aluminum blast furnace: Aluminum oxycarbide melts and Al-C-X (X=Fe,Si) liquid alloys

The thermodynamic properties and the phase relations were evaluated and estimated for the Al-O-C, Al-Si-C, and Al-Fe-C systems which are important to understand the chemical behavior in an aluminum blast furnace. The mixing properties of binary liquid alloys, including metal-carbon systems, were represented by the Redlich-Kister equation. The properties of liquid Al−C and Si−C alloys were estimated so as to be consistent with their phase diagrams. The coefficients of Al−Fe and Fe−C liquids were evaluated from reported values for activity and enthalpy. The extrapolation to the higher order systems was made by Maggianu's method. The aluminum oxycarbide melt was represented by a subregular solution model. In the Al-O-C system, liquid alloy/oxycarbide melt equilibria were calculated and compared with earlier experimental results and estimates. Attempts were made to clarify the volatilization of aluminum oxycarbide melts, and also the carbidation of liquid aluminum alloys. An empirical correlation between the first terms of the Redlich-Kister equation for the enthalpies and the excess entropies was discussed.     

New Methodological Approach to Investigation of Kinetics of REE Extraction in Nonstationary Conditions

The influence of periodical oscillations of the temperature on extraction and stripping processes in the extraction systems was studied. Two extraction systems were investigated： （1） 6 mol · L^-1 NaNO3-Nd（NO3）3-Pr（NO3）3-TBP kerosene and （2） [Nd（NO3）3 · 3TBP] -[ Pr（NO3）3 · 3TBP] -kerosene - 0.1 mol · L^-1 HNO3. Mathematical modeling of the nonstationary membrane extraction has been enhanced by including the dependence of the extraction rate constants on temperature. The values of activation energy for direct and reverse extraction and stripping reactions of Pr and Nd were calculated from experimental temporal dependencies of metal concentration and temperature by solving the reverse kinetics problem using the proposed mathematical model, A series of experiments with periodical oscillations of the temperature on the extraction system for the separation of rare earth elements （REE） using bulk liquid membrane between two extractors were performed. The mathematical model adequately describes the experimental data. The optimization of the extraction process for separation of REE by liquid membrane, under the influence of periodical oscillation of the temperature, was made based on the extraction rate constants and activation energies. The optimal conditions of separation by liquid membrane were found： frequency and amplitude of thermal oscillations, liquid membrane flow rate, and optimal ratio between organic and aqueous phase in extractors.