Interfacial composition, structural parameters and thermodynamic properties of water-in-oil microemulsions

The formation and structural characteristics of water-in-oil microemulsions comprising hexadecylpyridinium chloride (CPC), alkanols (C₄–C₆) and alkanes (C₅, C₈–C₁₀) have been investigated by the method of dilution. The compositions of the surfactant and the cosurfactant in the interfacial region (interphase) of the microemulsion droplets have been determined. The thermodynamics of transfer of the cosurfactants (alkanols) from the continuous oil (alkane) phase to the interface have been evaluated from dilution measurements at different temperatures. The structural parameters, radii of the droplet and the waterpool, aggregation numbers of CPC and the alkanols in the interphase of a droplet, and the nanoparticle density of solution have been estimated assuming monodispersity of the droplets. The thermodynamics and structural parameters have been examined in terms of the chain lengths of the alkanols and alkanes. Received: 12 September 2000 Accepted: 27 October 2000     

First-principles study of electronic structure of transition metal nitride: ReN under normal and high pressure

First-principles calculation was performed using tight-binding LMTO method with local density approximation (LDA) and atomic sphere approximation (ASA) to understand the electronic properties of rhenium nitride. The equilibrium geometries, the electronic band structure, the total and partial DOS are obtained under various pressures and are analyzed in comparison with the available experimental data. The most stable structure of ReN is NiAs like structure. Our results indicate that ReN can be used as a super-hard conductor. We estimated the average electron-phonon coupling constant to be 1.65 and superconducting transition temperature (T_c) is 5.1 K. The T_c value increases with the increase in pressure.     

Effect of solvent volume on the physical properties of undoped and fluorine doped tin oxide films deposited using a low-cost spray technique

Undoped and fluorine doped tin oxide films were deposited from starting solutions having different values of solvent volume (10-50 ml) by employing a low cost and simplified spray technique using perfume atomizer. X-ray diffraction studies showed that there was a change in the preferential orientation from (2 1 1) plane to (1 1 0) plane as the volume of the solvent was increased. The sheet resistance (R_sh) of undoped SnO₂ film was found to be minimum (13.58 KΩ/□) when the solvent volume was lesser (10 ml) and there was a sharp increase in R_sh for higher values of solvent volume. Interestingly, it was observed that while the R_sh increases sharply with the increase in solvent volume for undoped SnO₂ films, it decreases gradually in the case of fluorine doped SnO₂ films. The quantitative analysis of EDAX confirmed that the electrical resistivity of the sprayed tin oxide film was mainly governed by the number of oxygen vacancies and the interstitial incorporation of Sn atoms which in turn was governed by the impinging flux on the hot substrate. The films were found to have good optical characteristics suitable for opto-electronic devices.     

Crystallization and structural relaxation in quasicrystalline Al6CuMg4

We report here electron microscopic, differential scanning calorimetric (DSC) and X-ray diffraction studies on the phase transition in Al₆CuMg₄ alloy. Structural analysis of the transformed crystalline phase suggests that some of the lattice sites, which define the vertices of triacontahedron - the basic volume element of three dimensional Penrose tiling for this system - are fractionally occupied. We also observed that the specific heat of the as grown quasicrystalline alloy reduces gradually from 1.08J/gm. K at 330K to the Dulong Petit value 0.84J/gm. K around 420K, due to structural relaxation of the quasicrystalline phase.     

Note on the Design Differentiability of the Static Response of Elastic Structures

This paper provides a new proof of design sensitivity of the static response of some typical structures. These structures (beams, plates, and plane elastic solids) have been described previously. A proof of design sensitivity of the inverse state operator was provided there, and design sensitivity of static response was derived. The proof presented here is simpler and self-contained.     

Weighted Influence Non-linear Gauge System (WINGS) – An analysis method for the systems of interrelated components

The WINGS method has been derived from DEMATEL and can be widely used as a structural model for analysis of intertwined factors and causal relations between them. Its novelty comes from an idea of including in one mathematical mechanism both strength (importance) and influence of the system components. In particular, WINGS can be applied as the MCDA method for evaluating alternatives when interrelations between criteria cannot be neglected. For the problem with independent criteria, WINGS reproduces the additive aggregation of preferences, a classical method in MCDA.     

Evaluation of SARs for the prediction of skin irritation/corrosion potential–structural inclusion rules in the BfR decision support system†

The German Federal Institute for Risk Assessment (BfR) has developed a Decision Support System (DSS) to assess certain hazardous properties of pure chemicals, including skin and eye irritation/corrosion. The BfR–DSS is a rule-based system that could be used for the regulatory classification of chemicals in the European Union. The system is based on the combined use of two predictive approaches: exclusion rules based on physicochemical cut-off values to identify chemicals that do not exhibit a certain hazard (e.g., skin irritation/corrosion), and inclusion rules based on structural alerts to identify chemicals that do show a particular toxic potential. The aim of the present study was to evaluate the structural inclusion rules implemented in the BfR–DSS for the prediction of skin irritation and corrosion. The following assessments were performed: (a) a confirmation of the structural rules by rederiving them from the original training set (1358 substances), and (b) an external validation by using a test set of 200 chemicals not used in the derivation of the rules. It was found as a result that the test data set did not match the training set relative to the inclusion of structural alerts associated with skin irritation/corrosion, albeit some skin irritants were in the test set.     

一体化电极电催化二氧化碳还原研究进展

电催化二氧化碳还原反应(E-CO₂RR)可在温和条件下将CO₂转化成高附加值燃料或化学品,近年来受到广泛关注,其在实际反应中涉及到气体扩散和多电子转移等复杂过程,构筑高效、稳定的催化电极是其发展的核心之一。然而,传统涂敷电极制备时,需要将催化剂与粘结剂混合涂覆于集流体表面,此过程会造成活性位点包埋和传质过程受限,致使催化剂活性位利用率下降,同时在反应过程中电极表面容易粉化,造成稳定性下降,难以重复利用。因此,如何调控电极反应界面,提升催化剂活性位的利用率仍面临挑战。将催化剂原位生长于集流体上得到的一体化电极可直接应用于电催化反应,不仅有利于提升活性位利用率以及电荷传输能力,还能有效调控三相界面处的微观反应环境(如pH、反应物及反应中间体的浓度等),从而实现电催化性能强化。本文综述了一体化电极用于E-CO₂RR的最新进展,分析了结构和表界面调控对E-CO₂RR性能的影响规律,并对该领域仍然存在的挑战和未来一体化E-CO₂RR电极的发展进行了评述与展望。     

基于雨课堂和BOPPPS改进模型的教学设计——以大学化学课程为例

在高等学校专业课程教学中融入思政教育教学的理念,是以"立德树人"为教育根本任务的基本要求。结合结构化学课程特点和教学内容,以"培养学生的哲学观和科学观、培养学生民族自豪感和自信心"的目标为切入点,提出结构化学教学中思政元素的融入策略,发挥结构化学课程的"育德功能",实现知识传授和价值引领的有机统一。     

Ternary zero-dimensional hybrid metal halides with dual emission

Bulk assemblies of zero-dimensional (0D) metal halides with ‘host-guest’ system provide a promising platform for rationally structural tunability and photoluminescence modulation. In this work, we first report a series of ternary 0D metal halides, (bmpy)₉[Pb₃Cl₁₁](MnCl₄)_2-2x(SbCl₅)_2x (bmpy⁺ = 1-buty-1-methylpyrrolidinium⁺, C₉NH₂₀⁺), where the organic cation bmpy⁺ cocrystallizes with [Pb₃Cl₁₁]^5- trimer clusters, [MnCl₄]^2? tetrahedra, and [SbCl₅]^2? pyramids. The emission color of (bmpy)₉[Pb₃Cl₁₁](MnCl₄)_2-2x(SbCl₅)_2x can be easily tuned from green to warm white and finally to orange-red by controlling the excitation wavelength or the [SbCl₅]^2?/[MnCl₄]^2? molar ratio, promising its potential for application in multicolor light-emitting devices or even in encrypting multilevel optical codes. This work presents a novel structural modulation strategy to fabricate superior ordered single-crystalline multicomponent materials with multifunctionalities of 0D luminescent metal halides.