高碘酸钾氧化中性红催化光度法测定痕量铱

在稀硫酸介质中 ,铱催化高碘酸钾氧化中性红 (NR)褪色 ,据此建立了测定痕量铱的新催化光度法。本法线性范围为 0～2 4× 1 0 -3 μg mL ,检出限为 9.2× 1 0 -5μg mL。对 0 .0 50 μgIr(Ⅳ )测定的相对标准偏差为 1 .3% (n =1 0 )。考察了 40多种共存离子的影响 ,允许 50倍量的Ru(Ⅲ ) ,50 0倍量的Au(Ⅲ ) ,2 50 0倍量的Pt(Ⅳ )、Pd(Ⅱ )及Rh(Ⅲ )存在。本法已用于冶金产品及岩矿中铱的测定 ,其相对标准偏差为 1 .1 %～2 .4% ,标准加入回收率为 97.8%～1 0 2 .6%。     

甲基红-高碘酸钾催化光度法测定铱

在稀硫酸介质中 ,铱可催化高碘酸钾氧化甲基红褪色 ,据此建立了一个测定铱的催化光度新方法。铱的浓度在 0～ 2 .0μg/ 2 5 m L范围内与催化反应速率呈线性关系 ,检出限为 6.44× 1 0 - 4μg/ m L。对 0 .1 μg Ir( )及 1 .0 μg Ir( )独立测定 1 0次的相对标准偏差分别为 1 .98%和 1 .82 %。本法对冶金产品和岩矿中铱测定的相对标准偏差为 0 .64%～ 2 .30 %,标准加入回收率为 98.8%～ 1 0 3.8%。     

甲苯胺蓝-高碘酸钾催化光度法测定铱

在稀硫酸介质和加热条件下 ,铱对高碘酸钾氧化甲苯胺蓝 (TB)有明显的催化作用 ,以此反应为基础建立一个测定铱的催化光度法。方法对铱 (Ⅳ )测定的线性范围为 0～ 0 1 6μg mL ,检出限为 6 89× 1 0 -6mg mL。对 2 0 μgIr(Ⅳ )测定的相对标准偏差为 1 4% (n =1 1 )。催化反应对Ir(Ⅳ )和甲苯胺蓝均为一级反应 ,催化反应的表观活化能为 1 0 3 34kJ mol。考察了 40多种共存离子的影响 ,大多数常见离子不干扰。本法用于某些冶金产品及岩矿中铱测定的相对标准偏差为 0 47%～ 2 3% ,标准加入回收率为 98 8%～ 1 0 2 3%。     

藏红T催化光度法测定痕量钌

在H2 SO4 和热水浴中 ,Ru(Ⅲ )催化KIO4 氧化藏红T褪色 ,由此建立了测定钌的新催化光度法。钌质量浓度在 0～ 0 0 0 32 μg mL范围内符合比尔定律 ,检出限为 3.3× 1 0 -8g L。对 0 .0 0 2 0 μg mLRu(Ⅲ )测定的相对标准偏差为 1 .7% (n=1 1 )。催化反应的表现活化能为 38.2kJ mol。催化反应对Ru(Ⅲ )和藏红T分别为一级反应。试验了 40多种共存离子的影响 ,允许 2 0 0倍量的Ag+、Pt(Ⅳ ) ,2 0倍量的Pd(Ⅱ )、Ir(Ⅳ )及Cu2 +存在。该方法可用于岩矿和冶金产品中钌的测定 ,相对标准偏差为 1 .1 %～ 2 .4 % ,标准加入回收率为 1 0 0 .3%～ 1 0 1 .5 %。     

二甲基黄催化动力学光度法测定痕量铱

基于在H3PO4介质中,Ir(Ⅳ)对KIO4氧化二甲基黄的反应具有催化作用,建立了测定痕量铱的新催化光度法.测定铱的线性范围为(3.2～8.8)×10-2 μg/mL,检出限为7.54×10-7 g/L.对0.04 μg/mL Ir(Ⅳ)测定的相对标准偏差为1.5%(n=11).该催化反应对Ir(Ⅳ)和二甲基黄均为一级反应,其表观活化能为103.8 kJ/mol.试验了40多种共存离子的影响,大多数的常见离子不干扰测定.用该方法测定了岩矿和冶金产品中铱的含量,相对标准偏差为0.93%～2.5%,加标回收率为98.2%～102%.     

阻抑氧化藏红T动力学光度法测定痕量铱

基于在稀硫酸介质中,痕量铱对溴酸钾氧化藏红T褪色反应的阻抑作用,建立了一个测定痕量铱的动力学光度法。非催化体系与催化体系在530nm波长处的吸光度差值与铱的浓度在0.08～0.18μg/25ml范围内呈良好的线性关系,检出限为7.03×10-11g·ml-1。对0.15μg/25ml铱(Ⅳ)测定11次的相对标准偏差为0.36%。方法用于冶金产品及岩矿中铱测定的相对标准偏差为1.02%～1.88%,加标回收率为98.6%～102.4%。     

铱催化高碘酸钾氧化钍试剂动力学光度法测定痕量铱

在磷酸和热水浴中,铱(Ⅳ)对高碘酸钾氧化钍试剂的反应具有催化作用,依此建立了测定铱的新催化光度法。铱的浓度在0.20μg/10mL～2.0μg/10mL范围内与催化反应速率有良好的线性关系,检出限为6.24×10-3μg/mL。对0.50μg/10mLIr(Ⅳ)测定的相对标准偏差为2.0%(n=10)。该催化反应对铱(Ⅳ)和钍试剂分别为一级反应,其表观活化能为81.66kJ/mol。实验了40多种共存离子的影响,大多数的常见离子不干扰。用该方法测定岩矿和冶金产品中铱的含量,相对标准偏差为1.0%～1.1%,加标回收率为95%～100%。     

甲基绿-高碘酸钾系统催化动力学光度法测定痕量铱(Ⅳ)

基于以H3PO4为反应介质,用HAc-NaAc(1+8)(pH5.7)作缓冲溶液,在沸水浴中加热条件下,痕量铱(Ⅳ)能灵敏地催化高碘酸钾氧化甲基绿的褪色反应,建立了一种测定痕量铱(Ⅳ)的新催化光度法。研究了反应的最佳条件。催化反应吸光度A与非催化反应吸光度A0的差值ΔA与铱(Ⅳ)的质量浓度ρ在0～2.0μg/25mL范围内呈良好的线性关系。检出限为2.97×10-10g/mL。对1μg/25mL铱(Ⅳ)测定的相对标准偏差为1.7%(n=11)。测定了动力学参数。该催化反应对铱(Ⅳ)为一级反应,总反应为准一级反应。反应的表观速率常数为4.613×10-4/s,表观活化能为40.56kJ/mol。该方法用于分子筛样品和活性炭中痕量铱(Ⅳ)的测定,回收率97.9%～104.4%。     

固绿FCF催化动力学光度法测定痕量钌

研究了钌(Ⅲ)催化高碘酸钾氧化固绿FCF褪色反应的反应条件, 测定了该反应的反应级数和表观活化能, 并建立了测定钌的新动力学光度法. 在选定实验条件下, 非催化反应体系与催化反应体系在633 nm波长处的吸光度差值与钌(Ⅲ)的质量浓度在0～0.001 μg/mL及0.001～0.0025 μg/mL范围内有良好的线性关系, 检出限为 9.53×10-11 g/mL. 对0.001 μg/mL钌(Ⅲ)测定11次标准偏差为1.7%, 方法的选择性好, 灵敏度高, 可用于钌精矿及合成样中痕量钌的测定.     

甲苯胺蓝指示反应动力学光度法测定痕量钌

在磷酸和热水浴中 ,钌 (Ⅲ )对高碘酸钾氧化甲苯胺蓝的反应具有催化作用 ,据此建立了测定钌的新催化光度法。钌在 0～ 0 .0 5 0 μg/ 2 5ml范围内与催化反应速率有良好的线性关系 ,检出限为 5 .5 3× 10 - 5μg·ml- 1。对 0 .0 30 μg/ 2 5ml钌 (Ⅲ )测定的相对标准偏差为 2 .0 % (n =11)。该催化反应对钌 (Ⅲ )和甲苯胺蓝分别为一级反应 ,其表观活化能为 5 0 .2 6kJ·mol- 1。试验了 4 0多种共存离子的影响 ,大多数的常见离子不干扰。该方法用于岩矿和冶金产品中钌的测定 ,相对标准偏差为 2 .1%～ 2 .4 % ,标准加入回收率为 10 0 .1%～ 10 5 .4 %。     

国产硅藻土吸附尿激酶机理的研究

在常温下, 尿激酶在浙江土和吉林土表面的吸附等温线分别为V型和II型; 焙烧后两者皆转为III型。吸附等温线类型与硅藻土表面结构、孔结构、表面ζ电位有关。在400℃焙烧的硅藻土等电点值最低, 吸附量最大; 改性后, 吸附量也发生改变。本文还测定了尿激酶在硅藻土表面的吸附形态, 其吸附等温线方程符合0/(1-0)=(Kc)^1/β, 并讨论了平衡常数K和尿激酶吸附功能链段数β随温度的变化。     

DFT Study on the Effect of Hydrogen-bond Formation on the Adsorption of Aminotriazines on Graphene

DFT calculations have been performed to explore the aminotriazine adsorption on graphene surfaces.Relative energies,equilibrium geometries and electronic structures of monomer and dimer of aminotriazine molecules adsorbed at the surface were investigated and analyzed in details.It was found that the hydrogen atoms in the NH2 group of aminotriazine molecules are directed toward the graphene surface,and the adsorption energy increases as the NH2 group is added.The adsorbed aminotriazine molecules facilely form a dimer through the hydrogen bonding interactions,and the two aromatic rings of optimized structure of 2-amino-1,3,5-triazine(B) dimmer(denoted by B2) and melamine(D) dimmer(denoted by D2) are parallel to the graphene sheet.The large deviation of the averaged adsorption energy of B2 and D2 compared to monor adsorption may reflect the increase of π-π repulsion and the effect of hydrogen bond formation.The electronic structure analyses reveal that the formation of hydrogen bonds in melamine dimer has great influence on the adsorption mode at the graphene surface.     

Effect of the temperature on the thermodynamic characteristics of the ion-exchange separation of substances on ionites

The basic results on the effect of temperature on the equilibrium and thermodynamic characteristics of ion-exchange systems and the use of this effect in developing reagentless methods for ion-exchange separation are considered.     

Investigations on the influence of the substrate on the crystal structure of sputtered LiCoO2

The influence of the uppermost substrate layer on the structural properties of sputtered lithium cobalt oxide (LiCoO₂) is discussed in this work. For this purpose, bare, oxidized, and platinum-coated silicon wafers, as well as stainless steel and titanium sheets, were used as substrates. The resulting crystal structure of LiCoO₂ deposited on these substrates was analyzed and discussed. The LiCoO₂ thin films were deposited by RF magnetron sputtering with different film thicknesses. A subsequent annealing step at 700 °C was performed to induce the crystallinity of LiCoO₂. The crystal orientation was determined by X-ray diffraction. The obtained results show a strong dependency of LiCoO₂'s crystal structure on the surface the film is deposited on. However, the strong influence of the film thickness reported in previous publications could not be observed. If LiCoO₂ is deposited on the substrates with a metallic surface, a strong (003) preferential orientation is obtained for a wide range of film thicknesses. In contrast, sputtering of LiCoO₂ on bare and on oxidized silicon wafers results in a (101) dominated crystal structure for the different film thicknesses. These experiments show the importance of the characterization of LiCoO₂'s crystal structure in the intended battery setup.     

La传感器在测定铝液凝固过程中La活度研究

微量稀土加入铝或铝合金中，如果加入方法、数量、时间得当，可明显改善材料的多项性能．稀土对铝及铝合金的影响规律和作用机理，已取得了一些进展，但对稀土铝合金的热力学性质，尤其是溶解态稀土的研究少有报导［‘，2］．本工作采用L即．95C。。。。FZ。。多晶作为固体电解     

第三相界面对高分子共混物粗化过程的影响研究

共混物相分离的机理已有研究［１］．但对共混物分散相的粗化过程的研究则不多见．１９７７年,Ｃａｈｎ等［２］预言第三相界面与低分子共混物之间存在的浸润作用对相分离过程应有较大影响．近年Ｔａｎａｋａ等［３］的研究结果表明,在几何空间受限的条件下,含有小分子...     

Processes on aluminium on the negative side of the open-circuit potential

Cathodic current—time transients were recorded on high-purity aluminium immersed into a neutral 2 M NaCl solution, when subjected to a potential pulse from a potential around the open-circuit potential, to different negative values. Hydration of the oxide layer occurs at potentials more negative than −1700 mV vs. SCE, whereupon hydrogen is evolved at the metal—hydrated oxide interface. A linear Tafel function is obtained for the maximum current attained in that potential region with a slope of 110 mV dec⁻¹ indicating that the Volmer reaction is the rate-determining step, and the exchange current density for hydrogen evolution at aluminium is estimated at 5 × 10⁻¹¹ A cm⁻². Anodic current responses to the return of the potential to the rest values were also recorded at three different time scales. The presence of some substances, formed at the more negative potentials, other than gaseous hydrogen, was detected and their dependence on potential and cathodic pulse duration is discussed.     

Study on the stability of the serotonin and on the determination of its acidity constants

The present work aimed at describing the spectral behaviour of the serotonin and to evaluate its acidity constants using three different methods, using two spectrophotometry titrations and a third method that involved point-by-point analysis, which permitted to monitor closely and determine the evolution of the serotonin species in solution as a function of time. The three methods allowed estimation of three acidity constants associated to the same number of functional groups that form part of the molecule. The results given by the point-by-point analysis were: log(beta1) = 24.95 +/- 0.12; log(beta2) = 20.20 +/- 0.10; log(beta3) = 10.89 +/- 0.018.