Enhanced Exfoliation Effect of Solid Auxiliary Agent On the Synthesis of Biofunctionalized MoS2 Using Grindstone Chemistry

Mass production and commercial availability are prerequisites for the viability and wide application of MoS₂. Here, we demonstrate enhanced grindstone chemistry for a one‐step synthesis of biofunctionalized MoS₂. By adding a SiO₂ auxiliary agent the exfoliation efficiency increases from 16.23% to 58.59% and a rapid and high‐yield exfoliation of MoS₂ is seen. SiO₂ exhibits a fragmentation effect, which reduces the lateral size and facilitates the exfoliation of MoS₂, thus inducing a high‐efficient paradigm in the top‐down fabrication of biofunctionalized MoS₂ nanosheets. The as‐prepared MoS₂‐chitosan (MoS₂‐CS) nanosheets display complete disaggregation and homogeneous dispersion, as well as a high content of chitosan (ca. 20 wt%). As a proof‐of‐concept application, the MoS₂‐CS nanosheets act as a biosorbent for Pb^II removal, exhibiting a good adsorption capacity and recyclability. This green and facile enhanced grindstone chemistry with minimal use of organic solvents and high‐throughput efficiency can be extended to the fabrication of other biocompatible inorganic 2D analogues for a variety of applications.     

Extraction of local coordination structure in a low‐concentration uranyl system by XANES

Obtaining structural information of uranyl species at an atomic/molecular scale is a critical step to control and predict their physical and chemical properties. To obtain such information, experimental and theoretical L₃‐edge X‐ray absorption near‐edge structure (XANES) spectra of uranium were studied systematically for uranyl complexes. It was demonstrated that the bond lengths (R) in the uranyl species and relative energy positions (ΔE) of the XANES were determined as follows: ΔE₁ = 168.3/R(U—O_ax)² ? 38.5 (for the axial plane) and ΔE₂ = 428.4/R(U—O_eq)² ? 37.1 (for the equatorial plane). These formulae could be used to directly extract the distances between the uranium absorber and oxygen ligand atoms in the axial and equatorial planes of uranyl ions based on the U L₃‐edge XANES experimental data. In addition, the relative weights were estimated for each configuration derived from the water molecule and nitrate ligand based on the obtained average equatorial coordination bond lengths in a series of uranyl nitrate complexes with progressively varied nitrate concentrations. Results obtained from XANES analysis were identical to that from extended X‐ray absorption fine‐structure (EXAFS) analysis. XANES analysis is applicable to ubiquitous uranyl–ligand complexes, such as the uranyl–carbonate complex. Most importantly, the XANES research method could be extended to low‐concentration uranyl systems, as indicated by the results of the uranyl–amidoximate complex (～40 p.p.m. uranium). Quantitative XANES analysis, a reliable and straightforward method, provides a simplified approach applied to the structural chemistry of actinides.     

苯胺蓝分光光度法测定痕量铬(Ⅵ)

在HCI介质中,铬(Ⅵ)与过量I-反应生成黄色 I-3,继而与水溶性苯胺蓝阳离子形成离子缔合物,使得苯胺蓝溶液褪色,其在605nm处产生一个强吸收峰.在最佳实验条件下,Cr(Ⅵ)的浓度在4.0×10-7-1.2×10-5mol/L范围内符合比耳定律.表观摩尔吸光系数ε为1.10×106L·Mol-1·cm-1.该法用于分析测定沱江水样中Cr(Ⅵ)的含量,结果令人满意.     

非视线紫外通信大气传输特性的蒙特卡罗模拟

基于蒙特卡罗方法建立了紫外光非视线传输多次散射模型,利用单次散射近似法和实验方法验证了模型的有效性,并利用该模型完成了非视线紫外光通信大气传输特性的模拟.模拟时光波长取紫外光通信的最佳工作波段(250 nm附近),分析了不同传输距离下能见度、风、雨、雾等参量对系统能量透射比的影响.结果指出,系统能量透射比随传输距离增大而剧烈减小,在天气较差传输条件下能量衰减得更快;风力大小的变化对通信系统影响不大.较近距离通信传输时(一两百米),通信系统受天气条件的影响较小.     

近红外光谱分析技术

介绍了近红外光谱分析技术的工作原理,阐述了其数学模型的建立及分析过程,总结了现有常用的化学计量学方法及各自的优点,最后简单的概括了近红外光谱分析技术的应用,尤其是在制药方面的应用.     

压制观瞄系统多光谱光轴平行性调校技术研究

鉴于压制观瞄系统光轴平行性是实现精确压制的一项指标,其特殊性在于保证回转机械轴、可见光轴、激光光轴的平行性,提出一种采用双光楔对压制观瞄系统光轴进行调校的方法, 通过转动双光楔,使光轴发生偏转,从而完成各光轴的平行。通过分析压制观瞄系统的结构,重点介绍了双光楔调校的原理与方法,并建立数学模型。采用Matlab对数学模型进行仿真,基于该调校原理搭建实验装置进行试验,试验结果表明,采用双光楔进行光轴调校方法可使三轴调校后的平行度误差不超过0.1 mrad。     

A resource-saving decoding scheme of the orthogonally concatenated codes for optical transport networks in FPGA

A decoding scheme of the orthogonally concatenated codes with low resource utilizations is proposed. In the optical transport networks (OTN), forward error-correction (FEC) techniques are used to reduce the errors which occur in transmissions. Two-orthogonal-concatenated (TOC) codes are widely used in FEC techniques for their powerful error-correction capabilities based on the iterative decoding procedure. However, the framing structure is complex so the decoding procedure is more difficult than the decoding of in–out concatenated codes. And the powerful error-correction capability relies on the multi-iterative decoding processing, thus how to effectively utilize the hardware resources is a very important problem. Especially when the decoding procedure is implemented in the field programmable gate array (FPGA) devices, effective optimizations are required for the limited resources. In this paper we present an iterative decoding scheme in FPGA with low resource utilizations. As an example, an actual engineering application under the G.975.1 recommendation is given to show the efficiency of the proposed design.     

基于Labwindows/CVI的无人机畸变测试系统设计

针对现代无人机电网电压畸变参数检测的需求,设计了一种基于Labwindows/CVI的无人机专用畸变测试系统;根据实际装备的需求,设计过程中注重便携的特点和模块化设计思想,完成了系统的硬件和软件设计;为了提高设计的准确性,该系统还采用硬件滤波和数字滤波两种滤波方式进行滤波;实际应用表明,该系统能够准确测出无人机电网的畸变参数与畸变频谱,且各项测试指标均达到了设计要求,能够满足无人机电网交直流畸变测试的需要。     

Equation of State and Elastic Constants of Compressed fcc Cu

First-principles calculations of equation of state and single-crystal elastic constants of copper are carried out up to twofold compression. The Helmholtz free energies are calculated using the quasi-harmonic phonon approach based on density-functional theory within both the local density approximation and the generalized gradient approximation （GGA）. We find that the results calculated within GGA agree better with the experimental measurements in overall. The equation of state and the zero-pressure single-crystal elastic constants are close to the experimental values.     

64通道一维位置灵敏电流分布探测器及其数据获取系统

针对高流强粒子束与绝缘毛细管相互作用的特点, 设计制作了一套64通道一维位置灵敏电流分布探测器及其配套的数据获取系统, 该探测器可分辨最小直径为1 mm的束斑, 通过数据获取系统可实现可视化自动数据采集。 用2 nA和200—2000 eV电子对探测器进行了定标, 并用10 μA和2000 eV的电子束穿越锥形毛细管后的出射电子, 对探测器及数据获取系统进行测试, 获得了出射粒子的位置分布谱及能量信息。 A 64 channel position sensitive current distribution detector with 1 mm position resolution was developed, while the data acquisition system is based on the LabVIEW software. The test result obtained by using a 2 nA, 200—2000 eV electron beam deflecting by different voltages and the position spectra of 10 μA, 2000 eV electrons transmitted through a glass capillary was measured. The result indicated that the detector can be used to detect the charged particles with strong beam current through the capillary.