镍,钴与zincon的络合吸附波研究：铜精矿中微量镍,钴的同时测定

有关利用络合物的极谱催化波连续测定镍,钴的报道较少。在研究铜-Zincon的极谱行为时,我们发现NH_4Cl-Na_2SO_3(pH=6.5～7.5)底液中当Zincon浓度>4×10~(-5)·mol/L时,单扫描示波极谱仪上有两个峰,其峰电位分别为-0.42V和-0.56v(vs.     

数字散斑相关方法与应用研究进展

数字散斑相关方法(digital speckle correlation method, DSCM)作为固体实验力学领域材料表面变形场测量的一种非接触式方法与其它技术相比具有一些独到的优点,其有效性已经在近20年中被众多的应用实例所证明.近年来该方法在理论上逐步完善,一些现代的数学理论和数学方法(例如:小波变换、遗传算法、神经网络等)逐渐被引入到该方法中;在实验中的各个技术环节上正在逐步的改进,其结果的精度逐步的提高,结果收敛的速度也逐渐的加快;其应用的领域正逐渐从常规材料的测试向一些新型材料测试、从宏观场逐渐向细微观尺度、从常规环境向比较恶劣的环境、从实验室测试逐步向工程现场应用、从静态准静态向动态准动态等方面发展.本文简要介绍了DSCM的基本原理和数学模型,在相关搜索的改进、相关系数的选择、灰度级的重建和图像识别方面的进展以及在材料力学性能测试,微尺度变形场测量等方面的应用.最后就这一实验测量技术的几个可能的发展趋势进行了预测.      

Synthesis of spherical LiFePO4/C via Ni doping

Spherical LiFePO₄/C powders were synthesized by the conventional solid-state reaction method via Ni doping. Low-cost asphalt was used as both the reduction agent and the carbon source. An Ni-doped spherical LiFePO₄/C composite exhibited better electrochemical performances compared to an un-doped one. It presented an initial discharge capacity of 161 mAhg⁻¹ at 0.1 C rate (the theoretical capacity of LiFePO₄ with 5 wt% carbon is about 161 mAhg⁻¹). After 50 cycles at 0.5 C rate, its capacity remained 137 mAhg⁻¹ (100% of the initial capacity) compared to 115 mAhg⁻¹ (92% of the initial capacity) for an un-doped one. The electrochemical impedance spectroscopy analysis and cyclic voltammograms results revealed that Ni doping could decrease the resistance of LiFePO₄/C composite electrode drastically and improve its reversibility.     

On B(4, 13) 2-Groups

A group G is said to be a B(n, k) group if for any n-element subset {a ₁,…, a _n } of G, |{a _i a _j  | 1 ≤ i, j ≤ n}| ≤k. In this article, we give a complete characterization of B(4, 13) 2-groups, and then obtain a complete characterization of B(4, 13) groups.     

Facile and efficient preparation of α-halomethyl ketones from α-diazo ketones catalyzed by iron(III) halides and silica gel

An efficient and mild method for the synthesis of α-halomethyl ketones from α-diazo ketones was developed using ferric chloride or bromide as the halogen source and silica gel as the hydrogen source, with good to excellent yields.     

Experimental investigation on surface deformation of soft half plane indented by rigid wedge

In this work, the mechanical behavior of a block of soft material subject to large deformation from a series of wedge-shaped indenters is evaluated. Data fields acquired from digital image correlation (DIC) are compared with the existing theoretical models. The slope angles of the wedges vary from 5° to 73.5°, and the minimum measurement uncertainties of the DIC system are established in advance to define the accuracy. It is concluded that the assumptions underpinning the analytical theory make it difficult to characterize large deformation of soft materials during contact. The strain fields are also obtained from the measured displacement field and verify the previously postulated existence of two deformation sectors, namely, a so-called shrinkage sector symmetric to the loading axis and an expansion sector, which become smaller with the increasing load and decreasing wedge angle.     

On B6- and B7-groups

A finite group G is said to be a Bn-group if any n-element subset A = {a₁, a₂,..., a_n} of G satisfies \left|A^2\right|=\left|\left\{a_i{a}_j|1\le i,j\le n\right\}\right|\le n(n+1)/2. In this paper, the characterizations of the B₆- and B₇-groups are given.     

Evaluating and managing the sustainability of investments in green and sustainable chemistry: An overview of sustainable finance approaches and tools

Green chemistry (GC) was developed to maximise resource efficiency and minimise hazards in chemical processes and products. Over time, the approach evolved into green and sustainable chemistry (GSC), which aims at promoting the development of an ecologically friendly society. GSC encourages society's reliance on sustainable materials and technologies/processes and supports the ambitious sustainability targets set by international organisations. It also steers public attention to the provision of sustainable solutions for producers, consumers and investors. Since GSC implementation requires significant financial investment, this paper describes a broad range of approaches and tools to assess the sustainability of potential investments and shows, although with a primary focus on environmental sustainability, how life cycle approaches could be used to define enhanced key performance indicators. Thus, the paper may serve as a useful reference for: (i) chemical companies interested in evaluating the sustainability performance of activities requiring financial investment, and (ii) investors interested in evaluating the sustainability of potential financial investments.