Yb~(3+)和Er~(3+)共掺杂氟硼酸盐玻璃材料光学跃迁及红外到可见上转换

利用 J-O理论和吸收光谱实验数据计算了 Er3 +掺杂的氟硼酸盐玻璃材料的光学跃迁参数 ,从而得到了一些能级间跃迁的振子强度、跃迁几率、分支比、及寿命等数据。在室温下观察到了在 970 nm LD激发下红色和绿色上转换发光 ,讨论了红色上转换发光强度与 LD电流的关系。     

Electrochemical Reduction of a Conjugated Cinnamic Acid Diazonium Salt as an Immobilization Matrix for Glucose Biosensor

Initial results on the synthesis of a new conjugated diazonium salt of trans‐4‐cinnamic acid diazonium fluoroborate, which is used for the chemical modification of the glassy carbon (GC) electrode with trans‐4‐cinnamic acid groups through electrochemical reduction, and direct covalent immobilization of glucose oxidase (GOD) on the cinnamic acid groups are presented. The chemically modified GC electrode exhibits a good selectivity relative to the bare GC electrode for the various possible interfering compounds in glucose analysis: namely ascorbic acid and 4‐acetamidophenol. Covalent immobilization of GOD on the chemically modified GC electrode produces a biosensor which responds to glucose concentration changes in the presence of a soluble redox mediator (ferrocenemethanol). The chemical modification of GC by cinnamic acid groups is potentially useful for the attachment of other enzymes and biochemical reagents.     

Luminescence characteristics of Dy3+ activated Na 2Sr 2Mg (BO 3)2F 2: Dy 3+ phosphor

In this paper, we have reported a new Na ₂Sr ₂Mg (BO ₃)₂F ₂:Dy ³⁺ thermoluminescence (TL) phosphor prepared via the wet chemical method. Prepared phosphor was characterized by X-ray powder diffraction, photoluminescence (PL), TL and scanning electronmicroscopy techniques. The scanning electronmicroscopic image of Na ₂Sr ₂Mg (BO ₃)₂F ₂:Dy ³⁺ phosphor confirms the micron size of particles. Under the PL study, the characteristic emission spectrum of Dy ³⁺ corresponding to ⁴F _9/2→⁶H _15/2 (481 nm) and ⁴F _9/2→⁶H _13/2 (576 nm) transitions was observed. The TL property of the as prepared phosphor was also found to be good. TL intensity of Na ₂Sr₂Mg(BO ₃)F ₂:Dy ³⁺ phosphors at 0.99 kGy exposure of γ-irradiations was compared with standard CaSO ₄:Dy phosphor. It was seen that TL intensity of Na ₂Sr ₂Mg (BO ₃)₂F ₂: Dy ³⁺ phosphors is 1.1 times less compared with the standard CaSO ₄:Dy TL dosimeter phosphor. The kinetic parameters are also discussed in detail. The values of activation energy E (eV) and frequency factor S (s ^?1) were found to be 0.57 eV and 1.25×10⁶ s^?1, respectively.     

Electrochemical properties of electrolyte for lead fluoroborate redox flow battery prepared with recovered lead

The electrochemical properties of electrolyte for soluble lead flow battery(SLFB) are a key factor for the improvement of its performance. Pb(BF₄)₂ in which Pb²⁺ ions are highly soluble is cheaper and more stable than conventional Pb(CH₃SO₃)₂. This paper presents the electrochemical properties of HBF₄ and Pb(BF₄)₂ prepared with recovered lead for the electrolytes of SLFB. The density difference of reagent grade and recovered lead electrolytes is less than 0.05 g/cm³ and their viscosities increase up to 132 %, 120 %, respectively when concentration of Pb(BF₄)₂ changes from zero to 2.0 mol·dm⁻³. The conductivity of 1.5 mol·dm⁻³ electrolyte prepared with recovered lead has a peak when concentration of HBF₄ is less than 1.0 mol·dm⁻³. The results of cyclic voltammetry, linear sweep voltammetry and constant current charge/discharge test showed that impurities of recovered lead exert insignificant influences on the Pb²⁺/Pb and Pb²⁺/PbO₂ reactions. These results are promising to apply recovered lead to SLFB.     

Revised Phase Diagram of the System NaF–NaBF4

Summary. The phase diagram of the binary system NaF–NaBF₄ was determined using the thermal analysis method. Subsequent coupled analysis of the thermodynamic and phase diagram data was carried out to calculate the thermodynamically consistent phase diagram. The system NaF–NaBF₄ forms a simple eutectic phase diagram with the calculated coordinates of the eutectic point: 8.1 mol% NaF, 91.9 mol% NaBF₄, and 385.7°C. The probable inaccuracy in the calculated binary phase diagram is 9°C.     

Mechanism of Dissolution of a Lithium Salt in an Electrolytic Solvent in a Lithium Ion Secondary Battery: A Direct Ab Initio Molecular Dynamics (AIMD) Study

The mechanism of dissolution of the Li⁺ ion in an electrolytic solvent is investigated by the direct ab initio molecular dynamics (AIMD) method. Lithium fluoroborate (Li⁺BF₄^?) and ethylene carbonate (EC) are examined as the origin of the Li⁺ ion and the solvent molecule, respectively. This salt is widely utilized as the electrolyte in the lithium ion secondary battery. The binding of EC to the Li⁺ moiety of the Li⁺BF₄^? salt is exothermic, and the binding energies at the CAM–B3LYP/6‐311++G(d,p) level for n=1, 2, 3, and 4, where n is the number of EC molecules binding to the Li⁺ ion, (EC)_n(Li⁺BF₄^?), are calculated to be 91.5, 89.8, 87.2, and 84.0 kcal mol^?1 (per EC molecule), respectively. The intermolecular distances between Li⁺ and the F atom of BF₄^? are elongated: 1.773 Å (n=0), 1.820 Å (n=1), 1.974 Å (n=2), 1.942 Å (n=3), and 4.156 Å (n=4). The atomic bond populations between Li⁺ and the F atom for n=0, 1, 2, 3, and 4 are 0.202, 0.186, 0.150, 0.038, and 0.0, respectively. These results indicate that the interaction of Li⁺ with BF₄^? becomes weaker as the number of EC molecules is increased. The direct AIMD calculation for n=4 shows that EC reacts spontaneously with (EC)₃(Li⁺BF₄^?) and the Li⁺ ion is stripped from the salt. The following substitution reaction takes place: EC+(EC)₃(Li⁺BF₄^?)→(EC)₄Li⁺?(BF₄^?). The reaction mechanism is discussed on the basis of the theoretical results.     

L-精氨酸·氟硼酸加合物的X射线粉末衍射分析

采用X射线粉末衍射法对L-精氨酸·氟硼酸加合物进行了分析.数据收集范围在2θ角从7°到80°(共64个观测点).采用最小二乘法对该加合物粉末衍射的晶胞参数进行了计算,实验表明:该加合物为正交晶系,空间群P212121,晶胞参数a=0.50702(6)nm,b=1.37288(12)nm,c=1.64880(15)nm,V=1.147713nm3;Z=4;ρ=1.52g/cm3,粉末衍射分析的结果与单晶结构数据相吻合.     

简便的"一锅法"合成氟代芳烃

本文采用改进的Schiemann反应, 合成了一些用Schiemann反应不易制得的氟代芳烃。本方法中, 芳烃氟硼酸重氮盐水溶液可不经分离, 室温下"一锅法"反应, 简便合成了对氟硝基苯、对氟苯乙酮, 氟代苯甲酸等, 分离产率为25-62%。     

Crystal Structure of L—arginine Fluoroborate

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