Strong adsorption of chlorotetracycline on magnetite nanoparticles

In this work, environmentally friendly magnetite nanoparticles (Fe₃O₄ MNPs) were used to adsorb chlorotetracycline (CTC) from aqueous media. Fe₃O₄ MNPs exhibit ultrahigh adsorption ability to this widely used antibiotic. The adsorption behavior of CTC on Fe₃O₄ MNPs fitted the pseudo-second-order kinetics model, and the adsorption equilibrium was achieved within 10 h. The maximum Langmuir adsorption capacity of CTC on Fe₃O₄ (476 mg g⁻¹) was obtained at pH 6.5. Thermodynamic parameters calculated from the adsorption data at different temperature showed that the adsorption reaction was endothermic and spontaneous. Low concentration of NaCl and foreign divalent cations hardly affected the adsorption. Negative effect of coexisting humic acid (HA) on CTC adsorption was also observed when the concentration of HA was lower than 20 mg L⁻¹. But high concentration of HA (>20 mg L⁻¹) increased the CTC adsorption on Fe₃O₄ MNPs. The matrix effect of several environmental water samples on CTC adsorption was not evident. Fe₃O₄ MNPs were regenerated by treatment with H₂O₂ or calcination at 400 °C in N₂ atmosphere after separation from water solution by an external magnet. This research provided a high efficient and reusable adsorbent to remove CTC selectively from aqueous media.     

信息系统等级保护实施方案研究与分析

本文重点研究了三级安全等级保护的基本模型和基本技术、设计思路,并指出了建设过程应该关注的几个关键问题。最后简单介绍了等保系统存在的安全风险。以期能对等级保护建设时提供参考。     

基于BP神经网络的GPS坐标转换

GPS空间定位系统利用卫星进行军事和民用定位与导航 ,其定位成果属于WGS 84坐标 ,而在区域工程测量中 ,常常采用的是地方坐标系 ,因而需要将WGS 84坐标转换为地方坐标。本文利用人工神经网络能够实现高度非线性的特点 ,设计出一种BP网络进行GPS坐标转换。通过与实际数据相比较 ,证明这种方法具有较好的转换效果     

基于PCI总线数据采集系统设计

PCI总线是一种高性能的高速外围设备接口总线。它很适合于高速数据采集与传输系统。文中分析了PCI总线系统的结构与特点，讨论PCI接口卡的硬件设计以及基于PCI接口卡的数据采集软件设计。     

MOF-Based Solid-State Proton Conductors Obtained by Intertwining Protic Ionic Liquid Polymers with MIL-101

Solid-state proton conductors based on the use of metal–organic framework (MOF) materials as proton exchange membranes are being investigated as alternatives to the current state of the art. This study reports a new family of proton conductors based on MIL-101 and protic ionic liquid polymers (PILPs) containing different anions. By first installing protic ionic liquid (PIL) monomers inside the hierarchical pores of a highly stable MOF, MIL-101, then carrying out polymerization in situ, a series of PILP@MIL-101 composites was synthesized. The resulting PILP@MIL-101 composites not only maintain the nanoporous cavities and water stability of MIL-101, but the intertwined PILPs provide a number of opportunities for much-improved proton transport compared to MIL-101. The PILP@MIL-101 composite with HSO₄⁻ anions shows superprotonic conductivity (6.3 × 10⁻² S cm⁻¹) at 85 °C and 98% relative humidity. The mechanism of proton conduction is proposed. In addition, the structures of the PIL monomers were determined by single crystal X-ray analysis, which reveals many strong hydrogen bonding interactions with O/N H···O distances below 2.6 Å.