环评与排污许可相互衔接和促进的思考

近年来,世界范围内的工业化和城市化进程明显加快,环境污染是全球性的危机。在我国的环保工作开展中,环境影响评价和排污许可是有效的环保工作手段,这两种手段的有效配合,分别从准入和运营的角度来实现了污染的有效控制,虽然环境影响评价在我国实施的时间非常长,但是,排污许可却是近年来才出现的,出现时间的不一致导致二者在衔接和促进的过程中面临着较大的困境。因此,针对这一情况,本文充分探析了环评和排污许可相互衔接和促进的策略。     

白炭黑粒子间距对天然橡胶复合材料性能的影响

分别采用不同分子链长度的改性剂乙二醇二缩水甘油醚、丁二醇二缩水甘油醚、己二醇二缩水甘油醚和聚乙二醇二缩水甘油醚(PEGDGE)对白炭黑进行隔离改性,研究改性白炭黑对天然橡胶(NR)复合材料性能的影响。结果表明:与未改性白炭黑填充的NR复合材料相比,改性白炭黑填充的NR复合材料的t10和t90缩短,FL和储能模量(G′)减小,硬度降低,拉伸强度、拉断伸长率和撕裂强度提高;当改性剂为PEGDGE(回转半径为1.11 nm)时,改性白炭黑的粒子间距最大,分散性最好,NR复合材料的交联密度最大,G′和损耗因子最小,物理性能最佳。     

Yellow resistant photosensitive resin for digital light processing 3D printing

Digital light processing (DLP) has been studied and developed in the field of three-dimensional (3D) printing in recent years due to its fast curing rate and high resolution. To reduce the cost and viscosity of the resin system, the aromatic polyurethane acrylates (PUAs) were used as oligomer. The matrix resin called PUH₂ consists of oligomers (PUA, bisphenol A polyoxyethylene ether dimethyl acrylate) and active diluents (hydroxyethyl acrylate, hydroxyethyl methacrylate). However, the photosensitive resin containing aromatic isocyanate groups was easily yellowed under ultraviolet light. In this article, we developed a resin for DLP 3D printing with yellowing resistance, excellent mechanical properties and high heat resistance. The optimal ratio of 3DP-PUH₂ resin was PUH₂/TPO/RYOJI-292/dye/nanosilica = 100/5/0.4/0.01/0.1, and its viscosity was 500 cp, which is suitable for DLP 3D printing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48369.     

Carbon content-dependent microstructures,surface characteristics and thermal stability of mechanical alloying derived SiBCN powders

Three types of SiBCN: carbon-lean, -moderate and -rich powders with the same Si/B/N mole ratio were subjected to high-energy ball milling to yield an amorphous structure. The effects of carbon content on microstructures, solid-state amorphization, surface characteristics and thermal stability of the as-milled powders were studied in detail. Results showed that the increases in carbon content can drive solid-state amorphization accompanied by strain-induced, crystallite refinement-induced and/or chemical composition-induced nucleation of nano-SiC from an amorphous body. The specific surface area increases as carbon content increases. The amorphous networks of Si–C, C–B/C–C, C–N, B–N and C–B–N bonds that compose the amorphous nature, but the species and contents of the chemical bonds are carbon content-dependent. Carbon-moderate powders possess satisfying thermal stability while carbon-rich ones perform the worst. Mechanical alloying derived SiBCN powders have outstanding oxidation resistance below 800 °C; however only carbon-moderate powders show desirable anti-oxidation ability at higher temperatures. Thus, mechanical alloying of SiBCN appears a suitable technique for developing amorphous matrix materials for practical applications.     

浅谈高等职业院校新教师教学能力持续发展提升

高职院校的教师教学能力对教学效果的影响及其重要,特别是高职院校对于"双师型"教师的需求,要求教师不仅在专业知识的讲授上掌握教学方法和技巧,同时要具备一定水平的实践技能。新教师作为学校师资队伍中的新生力量,其教学能力和水平的快速提升对整个学校的教学质量的保证都有积极的影响作用。文章作者结合自己的实践体会,就何如有效的使新教师在短期内教学能力迅速提升并持续发展提出一些建议。     

组成对Li-Mg-N-H系统储氢性能的影响

研究了2种不同组成(2Li NH2-1.1Mg H2和Mg(NH2)2-2.2Li H)的Li-Mg-N-H储氢材料系统储氢性能,通过P-C-T曲线以及脱氢反应动力学的测定,发现这2种组成的样品脱氢产物均为Li2Mg(NH)2,其在200℃以上具有良好的可逆性,可逆储氢量可达4.6%(质量分数)以上;2种组成的系统不同仅在于前者多余Mg H2而后者多余Li H,其对系统脱氢反应的热力学性质如焓变、熵变以及自由能改变不大,但多余Mg H2的样品较多余Li H的样品,系统脱氢反应的动力学较快,具有较低的活化能。     

水分和酸对油纸绝缘老化的协同加速作用研究

为研究水分和酸对油纸绝缘老化的协同加速作用,将不同初始含水量的绝缘纸和不同初始含酸量的绝缘油组成的油纸绝缘在110℃下进行加速热老化试验,并对其老化后绝缘纸的聚合度进行测试分析。结果表明:随着水分和酸初始含量的增加,油纸绝缘的初始降解速率和老化各阶段的平均降解速率均增加。单独增加油纸复合绝缘中的水分或酸含量时,绝缘纸在各个老化时间段的平均降解速率增加不明显。当油纸复合绝缘中的水分和酸的含量同时增加时,则绝缘纸在各个老化时间段的平均降解速率增加显著。酸添加量相同时,分子量越小的酸对绝缘纸的加速老化作用越明显。     

电子模拟声系系统的设计

针对目前检测声波电子线路时,存在精度低,误差大,耗时耗力等问题,设计了一种基于电子技术的模拟声系系统,该系统由主控制电路、发射脉冲接收电路、信号发生及整形电路、 时差显示及调节电路等组成。系统在电子线路声波发射脉冲的作用下产生四路波列信号,波列信号的时差及首波幅度等参数均可实时显示,并可通过按键实现精确调整。通过实验测试及实际应用表明,该系统的各项指标达到了设计要求,体积小巧,操作简便,精度高,误差小,适合现场及各种测试场合的使用。