短程反硝化耦合厌氧氨氧化工艺及其应用前景研究进展

短程反硝化以其碳源消耗量、废污泥产量、温室气体排量极低及无需曝气等优势,被认为是最具研究潜势的厌氧氨氧化底物供给技术,成为近年来研究热点。本文首先介绍了短程反硝化工艺原理;其次从污泥源、反应时间、碳源类型、碳源量及pH等5个方面总结了影响短程反硝化工艺启动因素;随后综述了短程反硝化耦合厌氧氨氧化工艺的重要研究进展,同时指出了耦合工艺实验研究与工程应用的不足,并提出了解决实验与工程应用缺陷的方案;最后展望了耦合工艺处理城市污水和工业硝酸盐废水的可行性及应用前景,认为全面分析工业硝酸盐废水化学组分与基于分子生物学水平的宏基因组学测序、元转录组学技术是未来耦合工艺同步处理城市污水和工业硝酸盐废水的研究重点。     

磁絮凝强化技术处理厌氧消化污泥脱水液

为满足后续生物处理单元对固体悬浮物（SS）和铁浓度的进水要求,采用磁絮凝强化技术对厌氧消化污泥脱水液进行预处理。通过正交试验和单因素试验,本文考察了混凝水力条件、聚合氯化铝（PAC）投加量、聚丙烯酰胺（PAM）投加量、磁粉投加量及药剂投加顺序对磁絮凝效果的影响。试验结果表明：磁絮凝强化技术在快搅300r/min（2min）、慢搅100r/min（15min）、静置10min时,依次投加磁粉（40mg/L）、PAC（30mg/L）、PAM（4mg/L）时处理效果最好。在此运行条件下,SS和Fe³⁺去除率分别为97.61%、98.24%、絮凝指数（FI值）取得最大值、zeta电位绝对值最小,絮凝效果最佳。与对照相比,磁絮凝强化技术对SS和Fe³⁺去除率分别可提高3.70%和10.82%,同时絮体最大沉降速度可提高33%。磁絮凝技术处理后的出水不仅可以满足后续生物处理单元对SS和铁浓度的要求,还可以有效提高磁絮凝体的沉降速度,减小沉淀时间,具有较好的实用价值。     

Double hysteresis loops and enhanced mechanical quality factor of Mn-doped 0.75PMN-0.25PT ceramics

Relaxor ferroelectric 0.75 Pb(Mg_1/3Nb_2/3)O₃-0.25PbTiO₃ (0.75PMN-0.25PT) ceramics with Mn-doping concentration of 0%, 1%, 2% and 3 mol% were prepared by two-step sintering. The phase composition, microstructure, dielectric property, ferroelectric property, piezoelectric property and electromechanical property were investigated. Results indicate that all ceramics exhibit pure perovskite phases and high density. Mn-doping induces some decrease in dielectric constant ε_r, dielectric loss tanδ, remnant polarization P_r, piezoelectric coefficient d₃₃, and electromechanical coupling coefficient k_p, while significant increase in mechanical quality factor Q_m and the figure of merit (FOM) of 0.75PMN-0.25PT ceramics. For 3 mol% Mn-doped 0.75PMN-0.25PT ceramics, Q_m enhances by 1449%, FOM increases by 923%, and tanδ decreases by 67%, which makes it more suitable for high power applications. Interestingly, double P-E loops are observed in 3 mol% Mn-doped 0.75PMN-0.25PT ceramics. The phenomenon was investigated by the symmetry-conforming principle of point defects and the internal bias field.     

Enhanced heat transfer in rectangular duct with punched winglets

Thermal performance of a heat exchanger duct with punched winglets(PWs) mounted on the upper duct wall has been examined for Reynolds number(Re) ranging from 4100 to 25,500. In the present experiment, two types of PWs: punched delta-and elliptical-winglets(P-DW and P-EW) with four punched-hole sizes were tested at a fixed attack angle, optimal relative pitch and height. Also, data of solid delta-and elliptical-winglets(DW and EW) were included for comparison. The investigation has shown that the P-DW yields higher thermal-performance enhancement factor(η) than the P-EW. Although the solid DW and EW with no punch have the highest heat transfer and friction loss, the PWs yield better η than the solid ones. For PWs, the P-DW with smaller hole size has the peak heat transfer and friction loss around 5.7 and 40 times over the smooth duct, respectively but the optimum η of 2.17 is seen for the one with a certain hole size. The PWs provide η at about 5%–8% above the solid winglets.     

巨型工程机械子午线轮胎高强度、低生热胎面基部胶配方开发

通过对国外知名品牌37.00R57和40.00R57规格巨型工程机械子午线轮胎胎面基部胶组成分析和物理性能测试,对我公司巨型工程机械子午线轮胎胎面基部胶配方进行优化设计。新开发配方半成品和成品胶料动态损耗因子分别降低37.9%和26.6%,胶料物理性能达到竞品水平,成品轮胎TKPH提升13.6%。     

基于近场动力学方法的含缺陷板Ⅰ型应力强度因子计算

针对含多缺陷板脆性断裂问题,引入非局部近场动力学理论,结合J积分计算含缺陷板Ⅰ型应力强度因子。通过含Ⅰ型单裂纹脆性板以及系列含等长双裂纹板的应力强度因子计算,验证该方法的可行性和计算精度。进一步应用于含不等长双裂纹、含孔及孔边裂纹脆性板的应力强度因子计算,验证了该方法对于计算含复杂缺陷板Ⅰ型应力强度因子的适用性,并分析了裂纹位置和长度及孔径等多缺陷板裂尖应力强度因子的影响。     

Silicate-based polymer-nanocomposite membranes for polymer electrolyte membrane fuel cells

Proton-exchange membrane fuel cells have emerged as a promising emission free technology to fulfill the existing power requirements of the 21st century. Nafion^® is the most widely accepted and commercialized membrane to date and possesses excellent electrochemical properties below 80 °C, under highly humidified conditions. However, a decrease in the proton conductivity of Nafion^® above 80 °C and lower humidity along with high membrane cost has prompted the development of new membranes and techniques. Addition of inorganic fillers, especially silicate-based nanomaterials, to the polymer membrane was utilized to partially overcome the aforementioned limitations. This is because of the lower cost, easy availability, high hydrophilicity and higher thermal stability of the inorganic silicates. Addition of silicates to the polymer membrane has also improved the mechanical, thermal and barrier properties, along with water uptake of the composite membranes, resulting in superior performance at higher temperature compared to that of the virgin membrane. However, the degrees of dispersion and interaction between the organic polymer and inorganic silicates play vital roles in improving the key properties of the membranes. Hence, different techniques and solvent media were used to improve the degrees of nanofiller dispersion and the physico-chemical properties of the membranes. This review focuses mainly on the techniques of silicate-based nanocomposite fabrication and the resulting impact on the membrane properties.     

Effects of high glucose on vascular endothelial growth factor synthesis and secretion in aortic vascular smooth muscle cells from obese and lean zucker rats

Type 1 diabetes is characterized by insulin deficiency, type 2 by both insulin deficiency and insulin resistance: in both conditions, hyperglycaemia is accompanied by an increased cardiovascular risk, due to increased atherosclerotic plaque formation/instabilization and impaired collateral vessel formation. An important factor in these phenomena is the Vascular Endothelial Growth Factor (VEGF), a molecule produced also by Vascular Smooth Muscle Cells (VSMC). We aimed at evaluating the role of high glucose on VEGF-A(164) synthesis and secretion in VSMC from lean insulin-sensitive and obese insulin-resistant Zucker rats (LZR and OZR). In cultured aortic VSMC from LZR and OZR incubated for 24 h with d-glucose (5.5, 15 and 25 mM) or with the osmotic controls l-glucose and mannitol, we measured VEGF-A(164) synthesis (western, blotting) and secretion (western blotting and ELISA). We observed that: (i) d-glucose dose-dependently increases VEGF-A(164) synthesis and secretion in VSMC from LZR and OZR (n = 6, ANOVA p = 0.002-0.0001); (ii) all the effects of 15 and 25 mM d-glucose are attenuated in VSMC from OZR vs. LZR (p = 0.0001); (iii) l-glucose and mannitol reproduce the VEGF-A(164) modulation induced by d-glucose in VSMC from both LZR and OZR. Thus, glucose increases via an osmotic mechanism VEGF synthesis and secretion in VSMC, an effect attenuated in the presence of insulin resistance.     

海洋石油平台涂装工程涂料损耗分析

涂料的损耗控制一直都是涂装施工的重要环节,由于造成损耗的因素过多,设计方、施工方、涂料制造商都很难精确地计算损耗系数,很不利于施工管理和成本控制。海洋工程是个新兴的产业,施工中涂料的损耗常借鉴造船行业的经验,但由于二者在涂装工艺、结构、涂装设备等方面存在着很大的不同,导致损耗的差别很大。通过对国内石油行业多个海洋石油平台的涂装工程施工,积累了海洋工程涂料的使用数据,对影响涂料损耗的表面粗糙度、涂装方式、钢结构的几何形状、操作技术、环境因素、涂料浪费、修补等各项因素进行分析,尝试对涂料的损耗系数进行精确的统计。通过制定减少损耗的措施,在施工中严格控制,保证了新建海洋石油平台的涂料损耗系数控制在1.0～1.5之间,使涂料损耗达到了比较精准的控制。     

旋转填充床中SO2与O2同时吸收的扩散-反应模型

In this paper the rotating packed bed, a new type of absorber, which has high mass-transfer characteristic by means of centrifugal field instead of gravity field, is used to study on stimulated flue gas desulfurization. Based on experimental data,a model of mass-transfer and reaction of the sulfur dioxide chemical absorption in the rotating packed bed reactor is proposed according to the film-theory. It can be used to predict the performance of the total absorption rate and the enhancement factor of the sulfur dioxide and oxygen simultaneous absorption in the rotating packed bed reactor.The prediction of the model is consistent with the experimental result varying operating conditions, and the relative error between experimental result and predicted result is below 12%. Some interesting potential projects of simultaneous absorption of sulfur dioxide and oxygen in the rotating packed bed reactor are also discussed.