纺织品中pH值的测定能力验证

为了了解国内纺织品检测机构对纺织品中pH值测定领域的整体水平,识别和掌握实验室存在的差异,加强纺织品检测机构的实验室能力建设,中国国家认证认可监督管理委员会(CNCA)组织了纺织品中pH值的测定能力验证活动,有16个省、市、直辖市的69个实验室参加,测试结果满意的实验室占78.26%.     

Synthesis and catalytic properties of tetraorganodistannoxanes containing silicon

Three tetraorganodistannoxanes containing silicon were synthesized and their catalytic properties in esterification and acetalization were observed via the reactions of acetic acid with isoamyl alcohol and butyraldehyde with glycol. The factors affecting the reaction, such as the catalyst dosage, reaction time and solvent, etc. were discussed. The results show that the three tetraorganodistannoxanes displayed similar good catalytic activities compared to dichlorotetrabutyldistannoxane in esterification and acetalization. When the dosage of [ClBu₂SnOSn-(CH₂SiMe₃)₂Cl]₂ was 1.5% based on the mass of reactant, the yield of isoamyl acetate was 91.8% and the yield of butyraldehyde glycol acetal 94.2%. The different alkyl and bridging groups on Sn sites in the structure of tetraorganodistannoxanes showed some influence on the catalytic activities of these compounds. __________ Translated from Chinese Journal of Applied Chemistry, 2007, 24 (11): 1265–1272     

Graphene-encapsulated iron microspheres on the graphene nanosheets

Graphene nanosheets (GNSs) loading graphene-encapsulated iron microspheres (GEIMs) were fabricated by heat treatment of graphene oxide nanosheets (GONs) with ferric trichloride (FeCl(3)). The special pentagon-hexagonal graphene shells have been produced by precipitation of carbon from metal carbide solutions, thanks to the high reactivity of GONs and ferric nanoparticles dispersing homogeneously between graphene layers. The morphology, structure and elemental composition of GEIMs were investigated by scanning electron microscope, X-ray diffraction and electron energy disperse spectroscope, respectively. The formation mechanism of GEIMs was proposed. Hollow graphene microspheres (HGMs) on the GNSs were obtained with the removal of ferric species in GEIMs. When used as the anode materials for lithium-ion batteries, the almost graphitic HGMs exhibit stable voltage platform at ca. 0.2 V, excellent cycle capability and higher reversible capacity of about 440 mAh g(-1) after 50 cycles and possess great potential application in lithium-ion batteries.     

IVSPlat 1.0: an integrated virtual screening platform with a molecular graphical interface

Background  

The virtual screening (VS) of lead compounds using molecular docking and pharmacophore detection is now an important tool in drug discovery. VS tasks typically require a combination of several software tools and a molecular graphics system. Thus, the integration of all the requisite tools in a single operating environment could reduce the complexity of running VS experiments. However, only a few freely available integrated software platforms have been developed.     

Preparation and characterization of imprinted microspheres for clopyralid

In this work, the molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs) for clopyralid (3,6-DCP) were successfully synthesized via precipitation polymerization using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker and a mixture of butanone (MEK) and n-heptane as porogen under the existence of azobisisobutyronitrile (AIBN). The morphologies, particle sizes, structures, adsorption properties and selective recognitions of polymers were investigated systematically. The average particle sizes of MIP3 and NIP3 were 2.76 μm and 2.15 μm. The apparent maximum binding amount (Q_max) of MIP3 and NIP3 were 67.50 mg·g^?1 and 65.02 mg·g^?1 in Scatchard analysis. Langmuir isotherm displayed that the Langmuir constant (K_l) of MIP3 and NIP3 were 0.015 L·mg^?1 and 0.0065 L·mg^?1, the saturation adsorption capacity (Q_max) of MIP3 and NIP3 were 63.23 mg·g^?1 and 58.17 mg·g^?1. Lagergren pseudo-second-order kinetic plot described that the adsorption process of MIP3 was visualized as chemical absorption. Selectivity analysis revealed that MIP3 possessed highly specific recognition for 3,6-DCP.     

基于拓扑描述函数的连续体结构拓扑优化方法

提出了一种利用拓扑描述函数(TDF)作为拓扑设计变量求解连续体结构拓扑优化问题 的新方法. 优化问题的目标函数是结构的整体柔顺性，约束条件为对于可利用材料的体积限 制. 这种方法不仅可以消除拓扑优化中经常出现的棋盘格式等数值不稳定现象，而且能够有 效地抑制传统算法处理此类优化问题时所引发的边界扩散效应. 与其它的基于水平集描述函 数的拓扑优化方法相比，所提出的算法不仅无需求解控制水平集函数演化的双曲守恒方 程，而且合理地考虑了目标函数的拓扑导数信息，因而使得算法的计算效率有了显著的提高.     

Flexible Liquid Crystal Polymer Technologies from Microwave to Terahertz Frequencies

With the emergence of fifth-generation (5G) cellular networks, millimeter-wave (mmW) and terahertz (THz) frequencies have attracted ever-growing interest for advanced wireless applications. The traditional printed circuit board materials have become uncompetitive at such high frequencies due to their high dielectric loss and large water absorption rates. As a promising high-frequency alternative, liquid crystal polymers (LCPs) have been widely investigated for use in circuit devices, chip integration, and module packaging over the last decade due to their low loss tangent up to 1.8 THz and good hermeticity. The previous review articles have summarized the chemical properties of LCP films, flexible LCP antennas, and LCP-based antenna-in-package and system-in-package technologies for 5G applications, although these articles did not discuss synthetic LCP technologies. In addition to wireless applications, the attractive mechanical, chemical, and thermal properties of LCP films enable interesting applications in micro-electro-mechanical systems (MEMS), biomedical electronics, and microfluidics, which have not been summarized to date. Here, a comprehensive review of flexible LCP technologies covering electric circuits, antennas, integration and packaging technologies, front-end modules, MEMS, biomedical devices, and microfluidics from microwave to THz frequencies is presented for the first time, which gives a broad introduction for those outside or just entering the field and provides perspective and breadth for those who are well established in the field.     

Free-Space QKD with Modulating Retroreflectors Based on the B92 Protocol

Free-space quantum key distribution (QKD) has attracted considerable attention due to its lower channel loss and link flexibility. It allows two participants share theoretical unconditional secure keys, and can potentially be applied to air-to-ground quantum communication to establish a global quantum network. Free-space QKD using modulating retro-reflectors (MRR-QKD) significantly reduces the pointing requirement and simplifies the structure of the mobile terminal, therefore making it suitable for lightweight aircraft such as unmanned aerial vehicle and Cubesat, etc. Based on intensity modulation of two non-orthogonal states and the B92 protocol, we proposed a scheme to improve the previous work (Optics Express 2018, 26, 11331). Our scheme simplifies the optical structure and shows more robustness in equipment imperfection. The analysis and simulation show that the number of multiple quantum well modulators needed in our scheme decreases from eight to three with similar performance. Additionally, while the previous scheme cannot work due to low modulator extinction ratio or high optical misalignment, our scheme can still operate.     

FOURIER-CHEBYSHEV PSEUDOSPECTRAL METHOD FOR THREE-DIMENSIONAL VORTICITY EQUATION WITH UNILATERALLY PERIODIC BOUNDARY CONDITION

A Fourier-Chebyshev pseudospectral scheme is proposed for three-dimensionalvorticily equation with unilaterally periodic boundary condition. The generalized stability and convergence are analysed. The numerical results are presented.     

Theoretical Investigation on the Hydrogen Evolution,Oxygen Evolution,and Oxygen Reduction Reactions Performances of Two-Dimensional Metal-Organic Frameworks Fe3(C2X)12 (X = NH,O, S)

Two-dimensional metal-organic frameworks (2D MOFs) inherently consisting of metal entities and ligands are promising single-atom catalysts (SACs) for electrocatalytic chemical reactions. Three 2D Fe-MOFs with NH, O, and S ligands were designed using density functional theory calculations, and their feasibility as SACs for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) was investigated. The NH, O, and S ligands can be used to control electronic structures and catalysis performance in 2D Fe-MOF monolayers by tuning charge redistribution. The results confirm the Sabatier principle, which states that an ideal catalyst should provide reasonable adsorption energies for all reaction species. The 2D Fe-MOF nanomaterials may render highly-efficient HER, OER, and ORR by tuning the ligands. Therefore, we believe that this study will serve as a guide for developing of 2D MOF-based SACs for water splitting, fuel cells, and metal-air batteries.