矿用隔爆兼本质安全型不间断直流稳压电源的设计

基于本质安全型电源的原理及特点,提出了一种矿用隔爆兼本质安全型不间断直流稳压电源的设计方案,详细介绍了该电源主要电路的设计。该电源采用LM317可调稳压芯片实现稳压功能,具有使用方便、电路简单、变换效率高、成本低等优点。测试结果表明,该电源达到了本安标准,满足了安全型电气设备的需求。     

基于等级保护的网络改造方法及异常情况分析与处理

本文介绍了在电力企业信息网中基于等级保护的网络安全防护改造方法。在具体案例中,针对网络改造过程中遇到的网络异常情况,技术人员通过逐一分析、排查,最终恢复正常网络,达到企业信息网络二级域改造的目的。网络安全防护改造方法以及异常情况分析排查案例对同类型企业在网络改造及异常排查工作中具有一定借鉴和指导意义。     

The Landscape of microRNAs in βCell: Between Phenotype Maintenance and Protection

Diabetes mellitus is a group of heterogeneous metabolic disorders characterized by chronic hyperglycaemia mainly due to pancreatic β cell death and/or dysfunction, caused by several types of stress such as glucotoxicity, lipotoxicity and inflammation. Different patho-physiological mechanisms driving β cell response to these stresses are tightly regulated by microRNAs (miRNAs), a class of negative regulators of gene expression, involved in pathogenic mechanisms occurring in diabetes and in its complications. In this review, we aim to shed light on the most important miRNAs regulating the maintenance and the robustness of β cell identity, as well as on those miRNAs involved in the pathogenesis of the two main forms of diabetes mellitus, i.e., type 1 and type 2 diabetes. Additionally, we acknowledge that the understanding of miRNAs-regulated molecular mechanisms is fundamental in order to develop specific and effective strategies based on miRNAs as therapeutic targets, employing innovative molecules.     

杂散电流对阴极保护效果影响的模拟实验

本文通过模拟地下管道阴极保护的现场，测定了地下的杂散电流及其对阴极保护效果的影响，并对相关问题进行了分析。     

当前热处理工艺设计的着眼点

本文从热处理工艺设计入手，阐述了工艺设计的衡量标准以及环保的重要性，论述了热处理工艺设计的特点和工程设计人员的任务。     

Protecting the infrastructure with thermal spray coatings—Technical note

Thermal sprayed aluminum and zinc provide long-term (> 20 years to first maintenance) corrosion control coatings. However, this application is usually more expensive than painting or galvanizing if thermal spraying (metallizing) is not integrated into the design and fabrication phases of new construction and repair projects. Aluminum and zinc metallized coatings are tough enough to withstand fabrication, transportation, and assembly operations. The improved capabilities and productivity of metallizing equipment for aluminum and zinc spraying are a major factor in their current cost competitiveness. The net result is that the cost difference between metallizing, paint, and galvanizing is getting closer every day. Even though the initial application cost of metallizing may be higher, the life cycle cost (LCC) and average equivalent annual costs (AEAC) are lower than paint coating systems. Metallizing LCCs, when properly engineered into the construction schedule, are equal to or less than paint coating LCCs. This article summarizes some metallizing considerations for installing improved corrosion control coating systems in new construction and in maintenance and repair of infrastructure. Editor’s Note: The following constants have been used to convert between English and Metric dimensions: 1ft²-0.0929 m²; 1lb/ft²-4.89 kg/m²; 1 mil=0.025mm. Presented at the 5th National Thermal Spray Conference (NTSC-93), Infrastructure Maintenance and Repair Session, 10 June 1993, Anaheim, CA.     

变流场情景下基于鱼类游泳特性的上溯通道分析

水电开发对洄游性鱼类的生境造成了影响,预测目标鱼类洄游期的上溯通道可为修建过鱼设施提供依据,从而减缓其负面效应。本文选取虎渡溪航电工程的下游河段作为研究区域,将长薄鳅、白甲鱼、异鳔鳅鮀作为目标鱼类,针对几种目标鱼类的游泳能力对不同流速进行分区后,得出了适用于多种过鱼目标的流速适宜度曲线,然后对研究区域过鱼期的典型流量进行了数值模拟。根据流速适宜度曲线对研究区域的多种过鱼目标进行了流速适宜度评价,并由评价结果预测了满足多目标过鱼要求的上溯通道。结果表明：流速适宜度评价最优区域出现的位置随流量变化而有所不同,低流量运行条件下出现在主流区域,而高流量运行条件下出现在主流区域两侧;上溯的通道面积占总面积的比例也随流量变化而有所不同,低流量运行条件下的占比约为高流量运行条件下的3 ~ 4倍。根据预测通道特征,对鱼道的进口布置及电站运行调度提供了建议。该结果可为相关鱼类的保护工作提供依据。     

Structural Investigation and Molecular Modeling Studies of Strobilurin-Based Fungicides Active against the Rice Blast Pathogen Pyricularia oryzae

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.     

The AFLATOX® Project: Approaching the Development of New Generation,Natural-Based Compounds for the Containment of the Mycotoxigenic Phytopathogen Aspergillus flavus and Aflatoxin Contamination

The control of the fungal contamination on crops is considered a priority by the sanitary authorities of an increasing number of countries, and this is also due to the fact that the geographic areas interested in mycotoxin outbreaks are widening. Among the different pre- and post-harvest strategies that may be applied to prevent fungal and/or aflatoxin contamination, fungicides still play a prominent role; however, despite of countless efforts, to date the problem of food and feed contamination remains unsolved, since the essential factors that affect aflatoxins production are various and hardly to handle as a whole. In this scenario, the exploitation of bioactive natural sources to obtain new agents presenting novel mechanisms of action may represent a successful strategy to minimize, at the same time, aflatoxin contamination and the use of toxic pesticides. The Aflatox^® Project was aimed at the development of new-generation inhibitors of aflatoxigenic Aspergillus spp. proliferation and toxin production, through the modification of naturally occurring molecules: a panel of 177 compounds, belonging to the thiosemicarbazones class, have been synthesized and screened for their antifungal and anti-aflatoxigenic potential. The most effective compounds, selected as the best candidates as aflatoxin containment agents, were also evaluated in terms of cytotoxicity, genotoxicity and epi-genotoxicity to exclude potential harmful effect on the human health, the plants on which fungi grow and the whole ecosystem.     

PAN/FPU Composite Nanofiber Membrane with Superhydrophobic and Superoleophobic Surface as a Filter Element for High-Efficiency Protective Masks

Recently, because of the outbreak of COVID-19, the demand for various types of filter elements in protective materials has increased globally. Furthermore, new requirements for the filtration performance of PM2.5 liquid (oil) particles have been put forward. In this work, Superhydrophobic and superoleophobic composite nanofibers with excellent filtration capacity for oil and salt particles are developed through the modification of polyacrylonitrile (PAN) by fluoro-polyurethane (FPU) doping. The results show that the PAN/FPU composite nanofibers doped with 9 wt% FPU has a uniform fiber morphology with a diameter of 240 ± 30 nm. Compared to the pure PAN nanofibers, the water-based contact angle of PAN/FPU increases from 90 ± 5° to 151 ± 5°, and the oil-based contact angle increases from 58 ± 2° to 152 ± 3°. Importantly, at a high flow rate of 95 L min⁻¹, the filtration efficiency of the PAN/FPU nanofiber membrane for 0.3 µm oil particles increases from 92 ± 1% to 99.2 ± 0.1%. After cyclic loading, the filtration efficiency of 0.3 µm oil particles remains above 98%. Meanwhile, the filtration efficiency for 0.3 µm salt particles remains at 98.23 ± 0.1%. The PAN/FPU nanofiber membrane developed in this work is effective in applications and has good market prospects as a protective filtration material.