Growth of the oxidized nickel nanoparticles on a DNA template in aqueous solution

Oxidized nickel nanoparticles ranging from 2 to 3 nm have been grown on a DNA template. The synthesized products have been characterized by AFM and XPS. The results showed that uniformly oxidized nickel nanoparticles can be grown and assembled on a DNA template. These assembled small NiO nanostructures may have some potential application as catalysts, magnetic materials or electrochromic films. Theoretically, this synthetic method can be applied to fabricate other metals on a DNA template.     

A Numerical Strategy for Freestream Preservation of the High Order Weighted Essentially Non-oscillatory Schemes on Stationary Curvilinear Grids

The weighted essentially non-oscillatory (WENO) schemes have been extensively employed for the simulation of complex flow fields due to their high order accuracy and good shock-capturing properties. However, the standard finite difference WENO scheme cannot hold freestream automatically in general curvilinear coordinates. Numerical errors from non-preserved freestream can hide small scales such as turbulent flow structures; aero-acoustic waves which can make the results inaccurate or even cause the simulation failure. To address this issue, a new numerical strategy to ensure freestream preservation properties of the WENO schemes on stationary curvilinear grids is proposed in this paper. The essential idea of this approach is to offset the geometrically induced errors by proper discretization of the metric invariants. It includes the following procedures: (1) the metric invariants are retained in the governing equations and the full forms of the transformed equations on the general curvilinear coordinates are solved; (2) the symmetrical, conservative form of the metrics instead of the original ones are used; (3) the WENO schemes which are applied for the inviscid fluxes of the governing equations are employed to compute the outer-level partial derivatives of the metric invariants. In other words, the outer-level derivative operators for the metric invariants are kept the same with those for the corresponding inviscid fluxes. It is verified theoretically in this paper that by using this approach, the WENO schemes hold the freestream preservation properties naturally and thus work well in the generalized coordinate systems. For some well-known WENO schemes, the derivative operators for the metric invariants are explicitly expressed and thus this approach can be straightforwardly employed. The effectiveness of this strategy is validated by several benchmark test cases.     

人工生命概述

介绍人工生命的研究与发展,指出人工生命的研究方法及其与之密切相关的基本理论,最后结合个人的观点给出了人工生命的研究方向。     

功率因数校正原理及PFC整流器的实现

电器设备的功率因数过低对电网造成的不利影响日益受到人们的重视。功率因数有源校正技术因此而迅速兴起。本文介绍功率因数校正（ＰＦＣ）原理，以及一个ＰＦＣ整流器的实现。     

内热式镀金担体汞富集管的制作及应用效果

介绍了内热式镀金担体汞富集管的制作方法、最佳工作条件和工作性能，应用该富集管对浙江遂昌已知金银矿区化探土壤样品中的吸附态汞进行测试结果表明：与目前实验室中常用的外热式金丝管的测试结果相比，内热式镀金担体汞富集管的富集效率高，尤其是对高含量的热释汞分析比金丝富集管更优。     

Furnishing Continuous Efficient Bidirectional Polysulfide Conversion for Long-Life and High-Loading Lithium–Sulfur Batteries via the Built-In Electric Field

Most catalysts cannot accelerate uninterrupted conversion of polysulfides, resulting in poor long-cycle and high-loading performance of lithium–sulfur (Li–S) batteries. Herein, rich p-n junction CoS₂/ZnS heterostructures embedded on N-doped carbon nanosheets are fabricated by ion-etching and vulcanization as a continuous and efficient bidirectional catalyst. The p-n junction built-in electric field in the CoS₂/ZnS heterostructure not only accelerates the transformation of lithium polysulfides (LiPSs), but also promotes the diffusion and decomposition for Li₂S the from CoS₂ to ZnS avoiding the aggregation of lithium sulfide (Li₂S). Meanwhile, the heterostructure possesses a strong chemisorption ability to anchor LiPSs and superior affinity to induce homogeneous Li deposition. The assembled cell with a CoS₂/ZnS@PP separator delivers a cycling stability with a capacity decay of 0.058% per cycle at 1.0 C after 1000 cycles, and a decent areal capacity of 8.97 mA h cm⁻² at an ultrahigh sulfur mass loading of 6 mg cm⁻². This work reveals that the catalyst continuously and efficiently converts polysulfides via abundant built-in electric fields to promote Li–S chemistry.     

基于分离涡方法的台北101大厦流固耦合风致响应分析

以台北101大楼为研究对象,应用一种新的湍流脉动流场产生方法(DSRFG)模拟了台北101大厦周围风场的湍流入口边界条件,采用分离涡方法对该建筑进行数值风洞模拟。根据大厦外形特征,建立了几何模型,用于大厦风荷载的数值模拟;基于大厦振动监测系统得到的结构模态、自振频率等数据,建立了大厦的结构模型,用于气弹响应分析。将计算结果与现场实测以及风洞测力试验的相应数据进行了对比,以验证数值风洞的有效性。对是否考虑流固耦合的大厦数值模型的等效风荷载及风致响应进行对比分析,并探讨了流固耦合效应对大厦周围风流场的影响。对该对象的研究结果表明,在顺风向上,建筑物的风致响应不易受流固耦合效应影响,而在横风向上,考虑了双向流固耦合的有限元模型,其等效静风荷载及加速度与位移响应均小于未考虑流固耦合的有限元模型。在流场上,流固耦合效应减小了建筑两侧的涡量,但会产生较大的脱落涡旋,可能会对下游建筑风环境造成不利影响。     

ZnO/g-C_(3)N_(4)复合光催化剂的制备及光催化还原U(Ⅵ)EI北大核心CSCD

以ZnO和三聚氰胺为原料,采用热聚合法制备ZnO/g-C_(3)N_(4)复合型光催化剂,并将其用于光催化还原U(Ⅵ)。通过SEM,XRD,XPS,PL,UV-Vis测试手段对样品的表面形貌、晶格结构、元素组成、光催化性能进行分析。结果表明:ZnO的掺杂降低光生电子与空穴的复合率,扩大材料对可见光的响应范围,使复合材料具有更高的光催化活性。在pH=5、投加量为0.5 g/L时,经过暗反应30 min和光反应30 min,对U(Ⅵ)的最高去除率可达97%。U(Ⅵ)可被还原为U(Ⅳ),光生电子e-是实现将U(Ⅵ)还原为U(Ⅳ)的主要因素。     

Based on the Study on Preparation and Properties of Co(II) and La3+-Doped TiO2 Electrochromic Film

Abstract

In order to improve the optical properties and coloration effect. Co(II) and La³⁺ doped TiO₂ thin films were synthesized via a sol–gel, by using butyl titanate as precursor on the surface of ITO conductive glass substrate. Several techniques were used to characterize produces. Adopting the Sol-gel technology, [CH₃(CH₂)₃O]₄Ti, La₂O₃, CoC_l2?6H₂O as the precursor, the composite membranes with different molar ratio of Ti, Ti/La, Ti/Co to be prepared on the ITO glass substrate, the optimum technological parameters for preparation of the base material of the electro-induced discoloration glass are determined. The structure and surface morphology optical and electrochromic properties of Co(II) and La³⁺-doped TiO₂ films were examined with X-ray diffraction (XRD) analysis, energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), and ultraviolet-visible spectrophotometer (UV-vis) DTA-TG analysis. It was found that:

1. The sintering temperature coating number, [CH₃(CH₂)₃O]₄Ti content of the TiO₂ film sample, and the doping category are the main factors that affect the structure and properties of the membrane based material;

2. Using two alcohol amine as chelating agent can effectively inhibit the formation of Ti (OH)₄ precipitation;

3. The properties of the TiO₂ glass film prepared by La₂O₃ and CoCl₂·6H₂O are fine;

4. Materials based on the preparation of a radiochromic film transmittance, high cyclic reversibility, cyclic voltammetry characteristics significantly, the results of the study for the electric induced radiochromic film-based material development and application provide a theoretical and experimental basis.

     

二氧化碳加氢制甲醇反应机理研究进展

随着工业的迅速发展，化石燃料的使用给生态环境带来的负面影响越来越凸显。其中，CO2作为主要的温室气体对全球气候变化造成严重的危害。CO2选择性加氢制甲醇是解决温室效应、发展绿色能源和实现经济可持续发展的重要途径之一。Cu基催化剂以其优异的催化性能和低廉成本而被广泛应用于CO2加氢制甲醇反应研究中。Cu基催化剂化学性质和电子特性的高度可调性，往往使其反应机理具有差异性，进而展现出不同的催化性能。针对Cu基催化剂催化CO2选择性加氢制甲醇的反应机理进行综述，旨在通过对反应机理的深入认识，为高效稳定的Cu基催化剂设计提供理论指导。