Solubility in the systems Rb2SO4-H2SO4-H2O and Cs2SO4-H2SO4-H2O at 25°

Conclusions The solubility of rubidium and cesium sulfates in aqueous solutions of sulfuric acid was studied at 25°. Rubidium sulfate forms the compounds 3Rb₂SO₄· H₂SO₄, Rb₂SO₄ · H₂SO₄, Rb₂SO₄·3H₂SO₄ and Rb₂SO₄·7H₂SO₄ with sulfuric acid, while cesium sulfate forms the compounds Cs₂SO₄·H₂SO₄; Cs₂SO₄·3H₂SO₄ and Cs₂SO₄ · 7H₂SO₄.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1166–1170, June, 1968.     

Nitration of pentaerythritol by HNO3-H2SO4-H2O system

Conclusions It was shown experimentally that the nitrating agent in the O-nitration of pentaerythritol by HNO₃-H₂SO₄-H₂O nitrating mixtures is not the nitronium cation but evidently the free unionized nitric acid molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 134–140, January, 1970.     

Solubility in the systems KClO4-RbClO4-H2O,KBrO3-RbBrO3-H2O,KIO3-CsIO3-H2O,RbClO4-CsClO4-H2O,RbBrO3-CsBrO3-H2O,RbIO3-CsIO3-H2O at 25°

Conclusions The solubility in the systems KClO₄-RbClO₄-H₂O, KBrO₃-RbBrO₃-H₂O, KIO₃-CsIO₃-H₂O, RbClO₄-CsClO₄-H₂O, RbBrO₃-CsBrO₃-H₂O, RbIO₃-CsIO₃-H₂O was studied at 25°. In all cases the formation of continuous series of solid solutions was established.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2631–2634, December, 1971.The authors would like to express their gratitude to A. I. Vulikh for his constant interest in this work and his valuable advice.     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Kristallstruktur von LiHC2O4-H2O

LiHC₂O₄ · H₂O crystallizes in space group P 1 with a₀ = 4.99, b₀ = 6.16, c₀ = 3.45 Å; α₀ = 96.3°, β₀ = 98.0°, γ₀ = 80.4° and Z = 1. The crystal structure has been determined by direct methods. Refinement by least squares methods resulted to R₁ = 8,3%. In the structure the oxalate group is not planar. The angle between the two O? C? O planes is 2.9°.     

Superhydrophobic and photocatalytic self-cleaning cotton fabric using flower-like N-doped TiO2/PDMS coating

Cellulose - Self-cleaning fabrics can be developed based on introducing two mechanisms of superhydrophobicity and photocatalytic activity to conventional fabrics. However, there are some downsides...     

Radiofrequency plasma decomposition of C n F2n+2-H2 and CF4-C2F4 mixtures during Si etching or fluoropolymer deposition

Microscopic decomposition processes and gas-solid interactions in C_nF_2n+2-H₂ and CF₄-C₂F₄ discharges are studied by comparing mass-spectrometric results with actinometric emission diagnostics. The role played by CF_x radicals is evident in the various processes of gas-phase formation of saturates and unsaturates as well as in the activation growth mechanism of polymer deposition.     

Quasi-unary homogeneous nucleation of H2SO4-H2O

We show that the binary homogeneous nucleation (BHN) of H2SO4-H2O can be treated as quasi-unary nucleation of H2SO4 in equilibrium with H2O vapor. A scheme to calculate the evaporation coefficient of H2SO4 molecules from H2SO4-H2O clusters is presented and a kinetic model to simulate the quasi-unary nucleation of H2SO4-H2O is developed. In the kinetic model, the growth and evaporation of sulfuric acid clusters of various sizes are explicitly simulated. The kinetic quasi-unary nucleation model does not have two well-recognized problems associated with the classical BHN theory (violation of the mass action law and mismatch of the cluster distribution for monomers) and is appropriate for the situations where the assumption of equilibrium cluster distribution is invalid. The nucleation rates predicted with our quasi-unary kinetic model are consistent with recent experimental nucleation experiments in all the cases studied, while the most recent version of the classical BHN model systematically overpredicts the nucleation rates. The hydration of sulfuric acid clusters, which is not considered in the classical model but is accounted for implicitly in our kinetic quasi-unary model, is likely to be one of physical mechanisms that lead to lower nucleation rates. Further investigation is needed to understand exactly what cause the difference between the kinetic quasi-unary model and the classical BHN model.     

高碘酸盐-硫脲-硫酸反应体系的非线性动力学

研究了KIO4 SC(NH2)2 H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象；在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值[KIO4]0/[SC(NH2)2]0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象.     

Computer simulation of RF induction-heated argon plasma discharges at atmospheric pressure for spectrochemical analysis-I. preliminary investigations

Models of induction coupled plasma (ICP) discharges are developed for arrangements important in spectrochemical analysis. These models account for the spatial distribution of gas properties and major energy losses found in high temperature discharges. Realistic gas flows, and sample particle motion and decomposition are incorporated into the models. Computer simulations based on these models provide spatial temperature, gas velocity, sample concentration, and radiation distributions for a number of experimental ICP discharge configurations. The alteration of these distributions for various operational parameters permits evaluation of some important factors in developing spectroohemical analysis with the ICP source. Recognized differences between theory and experiment are discussed.     

AuCl4-H2O2化学发光体系研究

本文发现, AuCl4^-在KOH和H2O2存在下会产生弱化学发光信号; 在此基础上建立了AuCl4^-H2O2-KOH-CTMAB体系测定金的新的简单的化学发光分析法; 方法的检测限为5.5ppbAn; 线性范围为10-800pph; 测定100ppb金溶液的相对标准偏差为6.5%; 并初步探讨了AuCl4^-化学发光的可能过程及表面活性剂的影响作用。     

MgSO4-H3BO3-H2O体系水热条件下结晶动力学

自然界中硼铁矿属于多元素(Ｆｅ、Ｂ、Ｍｇ)共生矿,使用价值很高,是我国未来硼资源的主要来源.根据我国硼铁矿品位低的特点,东北大学提出了硼铁矿高炉铁硼分离生产含硼生铁及富硼渣、富硼渣硫酸浸出一步法生产硼酸的火法工艺路线[1],矿石中的镁以硫酸镁的形式存在于母液中.母液经浓缩、过滤,主要成分为硫酸镁和硼酸水溶液,母液中硫酸镁和硼酸分离是目前急需解决的问题.当温度高于80℃时,硫酸镁在水中的溶解度随温度的升高而降低,硼酸的溶解度随温度的升高而增加[2].根据硫酸镁和硼酸的溶解度特点,在常温下将两者分离是不可能的,通过高温结晶…     

高碘酸钠-过氧化氢-盐酸黄连素化学发光体系的研究

１引言 盐酸黄连素是一种用于治疗肠道感染，毒性低、副作用小的天然药物。对盐酸黄连素的测定，化学发光法未见报道。本文发现，过氧化氢存在下，磷酸介质中盐酸黄连素与高碘酸钠反应产生强的化学发光。据此结合流动注射技术建立了在ＮａＩＯ４－Ｈ３ＰＯ４－Ｈ２Ｏ２－盐酸黄连素体系中测定盐酸黄连素的化学发光新方法。方法的检出限为 ３．８×１０－９ｇ／ｍＬ。线性范围是 １．０× １０－８－ ７．０ ×１０－６ｇ／ｍＬ。相对标准偏差为 ２．３％（ Ｃ８＝ １． ０ ×１０－６ｇ／ｍＬ； ｎ＝１１）。该法与药典方法对照，结果满意。…     

Palladium-catalyzed cascade synthesis of spirocyclic oxindoles via regioselective C2-H arylation and C8-H alkylation of naphthalene ring

A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladiumcatalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides,which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles.The protocol enables three C-C bonds formation via an intramolecular Heck reaction and sequentially regioselective C-H bond activation.     

Superhydrophobic behaviour of plasma modified electrospun cellulose nanofiber-coated microfibers

In this work, a method is presented for production of a textile cellulose fiber with non-wetting properties suitable for applications ranging from wound care and tissue engineering to clothing and other textile applications. Non-wettability is achieved by coating a textile cellulose microfiber with electrospun cellulose nanofibers, creating a large and rough surface area that is further plasma treated with fluorine plasma. High surface roughness and efficient deposition of covalently bound fluorine groups results in the fiber exhibiting non-wetting properties with contact angle measurements indicating superhydrophobicity (>150° water contact angle). It is an environmentally friendly method and the flexibility of the electrospinning process allows for careful design of material properties regarding everything from material choice and surface chemistry to fiber morphology and fiber assembly, pointing to the potential of the method and the developed fibers within a wide range of applications.     

高碘酸盐-硫脲-硫酸反应体系的非线性动力学

研究了KIO4-SC(NH2)2-H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象;在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值犤KIO4犦0/犤SC(NH2)2犦0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象.     

Using mesoporous silica MCM-41 for in-line enrichment of atmospheric volatile organic compounds

A mesoporous silica MCM-41 with pore size of 29A was synthesized and assessed for its applicability as a sorbent for in-line trapping of volatile organic compounds (VOCs) from air samples. Several commercially available microporous carbon molecular sieves, i.e., Carbosieve SIII, Carboxen 1000, Carboxen 1003, and Carbotrap purchased from Supelco, were employed to form either single sorbent traps or multi-sorbent traps for comparing adsorption properties with those of the silica MCM-41. A standard gas mixture containing more than 50 target compounds with size varying from C(2) to C(12) was adsorbed by these sorbents and the per carbon response of flame ionization detection (FID) for the target compounds was calculated for obtaining the adsorption profiles. While the multi-carbon sorbents show very uniform adsorption ability across the entire carbon range from C(3) to C(12), the mesoporous silica MCM-41, however, shows little sorption for smaller molecules from C(3) to C(7), but exhibit comparable sorption ability for C(8)-C(12) compounds. Desorption at various temperatures indicates that C(8)-C(12) compounds once trapped can be easily released at moderate temperatures of about 150 degrees C, whereas for carbon sorbents the desorption temperatures for sufficient recovery need to go beyond 300 degrees C due to much tighter hold-up in the microporous structure. Sorption ability for MCM-41 is also reflected on linearity. Compounds with sufficient sorption as suggested by the adequate per carbon response also exhibit excellent precision and linearity with R(2) close to unity, an important requirement for quantitative analysis of ambient VOCs.     

A Study of Crystallization in the System TiO2(Al2O3)-H2SO4-(NH4)2SO4-H2O in Obtaining Titanium-Aluminum Tanning Agent

The conditions under which a titanium-aluminum tanning agent is obtained from sulfuric acid solutions were studied. The composition was established and the properties were studied of the forming phases.     

Li2SO4-K2SO4-MgSO4-H2O体系及次级体系298.15K时的热化学研究

用连续滴定量热法研究Li2SO4-K2SO4-MgSO4-H2O体系及次级体系Li2SO4-K2SO40H2O、Li2SO4-MgSO4-H2O和K2SO4-MgSO4-H2O 298.15K时在离子强度为15-0.1范围内的比热容和稀释热, 并结合Debye-Huckel焓极限公式研究离子强度在15-0.0001范围内的表观摩尔焓。