Use of amalgam concentration cells for determination of transference numbers in solid electrolytes—I. Electronic transference numbers of β-aluminas

The determination of transference numbers for different doped as well as undoped sodium-β-aluminas has been carried out by means of a method based on emf measurements of amalgam concentration cells of the type Na_x2Hg_1−x2/sodium-β-alumina/Na_x1Hg_1−x1 at 25°C. The details of this method, whose validity extends also to cationic conducting solids other than β-aluminas, are described and discussed for comparison with the results of previous investigations.     

Use of amalgam concentration cells for determinations of transference numbers in solid electrolytes—II. some remarks on the thermodynamic treatment of amalgams

The thermodynamic properties and treatments of alkali-metal amalgams, in connection with emf measurements of amalgam concentration cells, are discussed in terms of different choice of standard state.     

Theoretical foundations and practical realization of molybdenum electrodeposition in ionic melts

Information on the chemistry and electrochemistry of molybdenum in ionic melts is considered and generalized. Data on the electrode potentials, chemical reactions involving molybdenum compounds, and mechanisms of electroreduction of the metal and its electrodeposition in the form of various cathodic deposits are discussed and systematized.     

Theoretical foundations of galvanic treatment of dielectrics and semiconductors in ionic melts

The behaviors of diamond, cubic boron nitride, and silicon and boron carbides in ionic melts were analyzed thermodynamically and studied by potentiometry and corrosion measurements. The redox reactions occurring at the dielectric (semiconductor)/ionic melt interface were assumed to give rise to an electrochemical potential and surface conductivity. Controllability of the electrochemical potential makes metallization of the materials considered possible. Techniques are suggested for the electrodeposition of molybdenum, tungsten, and their carbides onto diamond, boron nitride, silicon carbide, and boron carbide particles.     

Transport and retention of polymer-stabilized zero-valent iron nanoparticles in saturated porous media: Effects of initial particle concentration and ionic strength

This study investigated the transport and retention of polyacrylic acid and polyvinylpyrrolidone stabilized zero-valent iron nanoparticles (PAA-ZVIN and PVP-ZVIN) in saturated porous media. The transport experiments were conducted in sand packed columns. The breakthrough curves (BTCs) and retention curves of ZVIN were analyzed. Results of transport experiments showed that increasing initial particle concentration and ionic strength led to a decrease in ZVIN transport. The zeta potentials and hydrodynamic diameters of PAA-ZVIN were apparently more negative compared to PVP-ZVIN. Results indicated that some mechanisms such as aggregation, ripening, and surface roughness had considerable impact on ZVIN retention in porous media.     

A mixture of nitrogen dioxide and oxygen as a Lux acid in nitrate melts

The effect of an NO₂+O₂ gaseous mixture on a melt of sodium and potassium nitrates and the acid-base reactions of this mixture with some Lux bases were studied, measuring the potential of an oxygen electrode at a temperature of 260°C. It has been found that the NO₂+O₂ mixture acts as a Lux acid conjugated with NO⁻₃ anion as the base, even under the atmospheric pressure. The strengths of the NO₂ +O₂ acid and the NO⁻₃ base related to other studied conjugated acids and bases were qualitatively estimated from the shape of potentiometric curves of the acid—base reactions.     

硝酸三氮烷胺高能离子液体的合成及性能研究

以偏二甲肼为原料,经季铵化及复分解反应得到一种高能离子液体硝酸三氮烷胺,其结构组成经质谱和元素分析进行表征,采用差热–热重分析(DSC–TGA)研究了化合物的热稳定性,通过吉布斯最小自由能对其理论比冲进行了计算,并建立了该产物纯度的分析方法。结果表明:该化合物对高温比较敏感,热分解温度为146℃;用四氧化二氮为作氧化剂时,硝酸三氮烷胺/四氧化二氮的比冲性能优于偏二甲肼/四氧化二氮;所建立的该高能离子液体化合物的纯度分析方法准确可靠,有利于有效控制产品质量。     

Viscosity-molecular weight concentration relationships beyond the critical region in polymer solutions and melts

A multivariate regression analysis of viscosity-molecular weight-concentration data is presented which is superior to the methods currently used. Four sets of data from the literature are analysed to show the efficacy of the method.     

Transport of oxygen, sodium chloride, and sodium nitrate in biofilms

Diffusion coefficients of sodium chloride, sodium nitrate and oxygen were determined for heterotrophic biofilms. The biofilms were cultivated under different hydrodynamic and substrate loading conditions in tubular reactors resulting in biofilm densities between 3 and dry mass. Quantifying solute diffusion in the biofilm for these biofilms allowed to specifically evaluate the influence of biofilm density on diffusion while keeping other factors such as the type of substrate, the inoculum, and the reactor type constant. Two methods were used to measure diffusion coefficients. The two-chamber method was used to quantify the diffusion of sodium chloride and sodium nitrate. The diffusion coefficients for oxygen were measured based on oxygen concentration profiles in the biofilm measured using microelectrodes. The ratio between the diffusion coefficient in biofilm and water (f_D=D_F/D_W) was found to be lower than 1 in the majority of experiments. A clear correlation between f_D and biofilm density was found where f_D decreased with increasing biofilm density. For mean biofilm densities in the range of 10- can be approximated between 0.5 and 1. For larger densities of 20 or can be approximated as 0.8 or 0.4, respectively. For densities higher than is below 0.6. Advective transport mechanisms that would have resulted in f_D>1 can be neglected in the biofilms cultivated.     

Effect of wheat and barley varietal differences in nitrate concentration on plant analysis interpretation

Wheat and barley varieties from breeding plots in advanced yield trials were tested for NO₃ concentration in their stems at the tillering stage. The study was carried out for three years, at three different locations with a high number of varieties, aiming to determine whether there are varietal differences which could affect the interpretation of prognostic standards set up in a previous study.From nine comparisons between 12 different varieties it was shown that differences in NO₃ concentration occurred on only three occasions and these were due to factors which affect NO₃ in plants, other than genotypic.The study concluded that varietal differences in NO₃ concentration are not a critical consideration for the interpretation of prognostic standards for genotypes which have been developed for certain environmental conditions.     

Transport of proton in polymeric ionic exchange membranes in relation with the dissociated sorbed acid

The transport of proton in ion exchange membranes in contact with HCl and H₂SO₄ solutions is studied. The membranes are the Nafion® 117 cation exchange membrane and, on the other hand, the Selemion® AAV and the Morgane ARA anion exchange membranes. Sorption and water content measurements combined with the radiotracer technique point out the low dissociation degree of the acid present in the membrane phase. This low dissociation leads to the excellent permselectivity towards proton of the Nafion membrane, and it is also the factor which decreases the proton leakage in the two studied anion exchange membranes.     

Effect of temperature and electrolyte composition on the lithium-boron alloy anode in nitrate melts: Passivating films on solid and liquid lithium

The discharge characteristics of the Li(B) anode in molten LiNO₃-KNO₃ improve markedly at temperatures above the melting point of lithium. These results show the importance of the liquid anode concept for high rate batteries. The Li(B) anode is quite stable in the LiNO₃-KNO₃ melt at temperatures up to 300°C and yields current efficiencies exceeding 90%. This stability is lost in initially Li⁺-free melts such as NaNO₃-KNO₃ where rapid deterioration of the anode is observed. These experimental results are explained by a thin passivating Li₂O film on the anode that is destabilized in melts having low lithium ion concentrations where oxides are converted to peroxides and superoxides. Experimental thermodynamic values for the Li(B)/LiNO₃-KNO₃/AgNO₃ (0.17 m) cell at 250°C are E = 3.361 V, ΔG = −324.3 kJ, ΔS = −61.2 J K⁻¹ and ΔH = −356.3 kJ. Thermodynamically, the Li(B) anode functions essentially as a lithium electrode.     

Properties of fused polysulphides—III. EMF measurements on the sodium-sulphur cell,and sulphur activities and constitution in fused sodium polysulphides

Expressions are derived for the emf of the sodium-sulphur cell in the fully charged state (E₂) and in a partly discharged state (E₁). It is shown that (E₂  E₁) is related to the variation of sulphur activity with the composition of the sodium polysulphide melt produced in the cell reaction, and that the sulphur activity can be calculated if E₁ is known over a range of compositions. The sulphur activity in sodium polysulphide melts was also measured by a transpiration method. The two sets of results are in good agreement.The emf of a sodium polysulphide concentration cell with transference (E₃) was also measured. The results show that all the sulphur in the melt is contained in polysulphide anions; no free sulphur is present.     

离子强度和溶质浓度对蛋白质在Q Sepharose FF中吸附动力学的影响

采用孔扩散模型, 模拟不同盐浓度和不同蛋白质初始浓度条件下,吸附牛血清白蛋白(BSA)的动态吸附曲线并获得孔扩散系数;考察了离子强度和溶质浓度对蛋白质在阴离子交换剂Q Sepharose FF中吸附动力学的影响.结果表明,蛋白质的孔扩散系数随初始浓度的增大而下降;在氯化钠浓度小于0.10 mol•L^-1的范围内,蛋白质的孔扩散系数随着盐浓度的增加而增大,但当盐浓度增大到0.15 mol•L^-1时又有所降低,表明存在着一个最佳的离子强度,使蛋白质的孔扩散系数最大.     

离子液体中CuI/L-Proline催化烯基碘化物与硫酚的偶联反应

用离子液体[Bmim]BF4为溶剂,CuI/L-Proline催化3-碘代环己烯酮与硫酚的偶联反应,结果发现以20 mol% L-Proline、10 mol% CuI组成的催化体系,在110 ℃下反应6～10 h,产率可达82%以上.     

全熔融法生产高浓度硝铵磷复合肥技术开发和应用

阐述了云峰分公司针对硝铵的改性自主研发的全熔融法生产高浓度硝铵磷复合肥(30-10-0)的生产技术,对生产原理、工艺流程、工艺参数、生产进展,以及技术开发过程中的设备改造等方面作了总结。在硝铵改性生产高浓度硝铵磷产品开发过程中,进行了技术创新,采用低共熔体配方对硝铵改性,在不添加阻爆剂的情况下通过国家抗爆检测试验;进行了设备创新,应用了差动双速旋转造粒机,实现了在高44 m硝铵造粒塔中生产高浓度复合肥。该技术优势明显,产品w(总养分)≥40%,w(硝态氮)/w(总氮)≥46%,质量优于国内同类产品;效益好,仅投资314万元,可增加利润4 096万元。