Binder-free combination of graphene nanosheets with TiO<Subscript>2</Subscript> nanotube arrays for lithium ion battery anode

Binder-free combination of graphene nanosheets with oriented TiO₂ nanotube arrays was designed and achieved via one-step facile electrodeposition. The structure and morphology of as-prepared composite graphene nanosheets/TiO₂ nanotube arrays were studied in terms of SEM, FESEM, EDX, TEM, Raman and FTIR. Furthermore, the corresponding electrochemical performances were evaluated in terms of galvanostatic charge/discharge, cycle stability and AC impedance. As expected, the composite graphene nanosheets/TiO₂ nanotube arrays displayed higher discharge capacity, cycle stability and Li⁺ diffusion coefficient than bare TiO₂ nanotube arrays. High Li-storage activity, superior conductivity and large surface area of graphene nanosheets should be responsible for improved electrochemical performances.     

Preparation and properties of polyimide solvent‐resistant nanofiltration membrane obtained by a two‐step method

This study investigated the preparation of polyimide solvent‐resistant nanofiltration membranes by a two‐step method (casting the membrane first and then crosslinking by the thermal imidization method). The influences of polymer concentration, thickness of membranes, temperature of the imidization, phase inversion time and thermal imidization procedure were studied. The membranes with the highest rejection rate of Fast Green FCF (molecular weight 808.86 g mol^?1) were prepared in the following conditions: polymer concentration 13 wt%, phase inversion time 1 h, membrane thickness 150 µm and thermal imidization procedure 200 °C for 2.5 h, 250 °C for 2 h and 300 °C for 2 h in a vacuum environment; the heating rate was 5 °C min^?1. The membrane was stable in most of the solvents tested and the fluxes of some common solvents were equal to or higher than a number of commercial solvent‐resistant nanofiltration membranes. A much higher rejection of dyes in water than in methanol was observed in the filtration experiments and a new way to explain it was developed. Copyright © 2011 Society of Chemical Industry     

基于NI软件的S参数自动测量系统

为了提高手动测量微波器件相关产品的S参数的效率,解决测试报告生成自动化问题,根据产品的测试原理和要求,结合TestStand和Labview这两款NI软件的各自优势,从而实现产品相关参数测试的自动化。论文介绍了该系统的构成,详细介绍软件设计流程和功能实现,测试实例表明:该系统提高了测试效率,精度高。     

Analyzing the Adaption of Different Adsorption Models for Describing the Shale Gas Adsorption Law

The adsorption capacity of a shale gas reservoir is mainly determined by the isothermal adsorption experiment. In this study, the building conditions and performances of seven single‐component and five multi‐component adsorption models were compared and analyzed. The results show that most shale gas reservoir adsorption characteristics obey those of type I on the macroscopic scale. The adsorption isotherms of single components can be described by the Langmuir‐Freundlich, Langmuir, and Toth models. The revised Langmuir, extended Langmuir, and the loading ratio correlation (LRC) models can be applied to binary‐component mixtures; and the extended Langmuir and LRC models perform best for shale gas. The obtained results might have an important promoting effect for modeling the shortage of shale gas.     

浅析如何加强水利工程水闸的安全管理

水闸作为水利工程中最重要的基础建筑设施，具有资源调配、防洪、灌溉等功能。本文介绍了如何加强水利工程安全管理的方法，希望为水利工程建设做出贡献。     

Synthesis and structural characterization of α-MoO3 from molybdic acid wastewater

The study investigated the use of ethylene glycol to form α-MoO₃ from molybdic acid wastewater by thermal treatment at 300 °C for 1 h. The color change, pH values, and residual molybdenum concentration in the wastewater were dependent on the reaction times that were used. The results of UV–visible and Fourier transform infrared (FTIR) spectroscopy were used to explain the reaction process. During the treatment process, the morphologies of the constituents were observed using scanning electron microscopy. In this work, X-ray photoelectron spectroscopy and transmission electron microscopy demonstrated that when the molybdenum oxide powder was treated thermally at 300 °C, the material exhibited crystallinity, and the peaks were indexed to correspond with the (002) and (200) crystallographic planes, which were identified as orthorhombic molybdenum trioxide (α-MoO₃). In addition, the FTIR and X-ray photoelectron spectroscopy confirmed that α-MoO₃ powder had been synthesized.     

A network prototype for integrated production-distribution planning with non-multi-functional plants

This paper proposes a two-echelon network prototype for integrated production and distribution planning where non-multi-functional plants supply multiple types of products with limited quantities to the customers via capacitated warehouses. Four variations of the prototype, formulated as individual mixed integer programming models, are solved using the branch and bound algorithms by numerical experiments to examine the cost implications of production-distribution strategies involving single-sourcing constraints on different levels of the supply chain. Further discussions on the practicality and versatility of the proposed prototype (i.e. its ability to consider different facility locations, specialised capabilities of individual plants, safety stock levels and demand characteristics) illustrate the usefulness of the prototype to industry practitioners when making strategic and/or tactical decisions.     

Microstructural evolution and its influence on creep and stress relaxation in nanocrystalline Ni

Indentation creep and stress relaxation tests were performed on rolled and annealed nanocrystalline (NC) Ni to study the influence of microstructure evolution on plastic deformation behavior. Dislocation density (ρ) increases with increasing rolling strain, reaching a maximum at 20% strain, followed by a decrease at larger strain. The ρ of Ni decreases significantly with increasing annealing temperature. Softening behavior is observed in NC Ni with grain size <40 nm, i.e., an inverse-like Hall–Petch effect. For rolling NC Ni, both creep strain rate and rate sensitivity first increase and then decrease, while those of annealed Ni continuously decrease. With increasing grain size, creep activation volume unusually decreases first, then starts to rise, which is different from that of coarse-grained metal. A model involving dislocation annihilation and emission at grain boundaries under indenters is used to explain the anomalous behavior of rolled and annealed Ni, respectively.     

Synthesis of morphology-controlled mesoporous transition aluminas derived from the decomposition of alumina hydrates

Aluminum hydroxides were synthesized through the acidification of sodium aluminate solution using single organic diester or diacid as pH adjustor and aluminum chelating agent. The obtained alumina hydrates are investigated by XRD, SEM, IR and TG. Bayerite firstly formed at room temperature, and its morphology greatly varied with the pH adjustors used, which probably attributes to different kinetics of the acidification. The bayerite can evolve to gibbsite and boehmite after the hydrothermal treatment at 100 °C and 145 °C, respectively, where these alumina hydrates show diverse morphologies. After the calcination, these alumina hydrates of bayerite, gibbsite and boehmite could pseudomorphically transform to the corresponding η-, χ- and γ-aluminas, respectively, exhibiting different structural and textural properties. Interestingly, the transition aluminas derived from the aluminum tri-hydroxides, bayerite and gibbsite, both display locally organized mesopores, while no such meso-structure can be observed in γ-alumina obtained from the aluminum mono-hydroxide, boehmite. The changes of bayerite during calcination are investigated detailed. The dehydration of non-porous bayerite accompanied with the formation of meso-structured transition aluminas, where the meso-structure becomes more and more clearly defined and pore size expands with the calcination temperature increasing.     

食品防腐剂的使用现状及安全性分析

食品防腐剂主要用于抑制微生物的生长繁殖,以延长食品的保存期。分析了我国食品防腐剂的使用现状、常用的防腐剂的种类及性能、防腐剂使用中存在的问题及安全性评价指标,提出了安全使用防腐剂的建议。