锈蚀钢筋混凝土梁的疲劳性能

对8根模拟锈蚀钢筋混凝土梁进行了高周疲劳试验,研究和探讨了模拟锈蚀钢筋混凝土梁的疲劳性能。结果表明,交变荷载作用下试件的斜裂纹出现并迅速发展成主裂缝;模拟锈蚀钢筋混凝土梁多在端部发生剪切疲劳破坏;试件的挠度发展、裂缝分布与破坏形态密切相关;随循环次数增加,锈蚀主筋的最大、最小应力不断增长,应力幅值基本不变;混凝土的最大、最小压应变快速增长,应变幅值平稳增长;试件的疲劳寿命具有较大的离散型;同等条件下,锈蚀钢筋混凝土梁的疲劳寿命往往比锈蚀钢筋的轴向拉伸疲劳寿命长。     

公共权力运行中的公共利益悖论及其消解

公共利益是公共权力运行的逻辑起点和价值追求。然而,公共利益的抽象性与具体性、正当性与恰当性、整体性与个体性、公共性与私利性以及“权利优先于善”还是“善优先于权利”之间,存在着悖论现象。消解公共利益悖论,需要遵照合法性、正当性、价值位阶和比例原则,建立健全利益表达、政府回应、冲突整合、行政公益诉讼、法律约束等长效机制。     

天然产物基Gemini表面活性剂研究进展

介绍了Gemini（双子）表面活性剂的新型结构及传统表面活性剂所不具备的优异性能：更高的表面活性,更低的临界胶束浓度（CMC）,有效的润湿性,低温水溶性,良好的增溶性,独特的流变性,优良的钙皂分散性能。重点分析了天然产物基Gemini表面活性剂因结合了Gemini表面活性剂的高效性和天然产物的绿色性,有着可观的研究发展价值。分别介绍了糖基、天然油脂基、松香基Gemini表面活性剂的合成方法与应用领域,指出探求合成步骤少、简易便行的合成方法以及探索Gemini表面活性剂与传统表面活性剂的复配体系性能是今后的研究重点。     

Preparation of Docosahexaenoic Acid-Rich Diacylglycerol-Rich Oil by Lipase-Catalyzed Glycerolysis of Microbial Oil from Schizochytrium sp. in a Solvent-Free System

Docosahexaenoic acid (DHA)-rich diacylglycerol (DAG)-rich oil was prepared by lipase-catalyzed glycerolysis of microbial oil from Schizochytrium sp. in a solvent-free system. The reaction parameters including lipase type, substrate molar ratio, temperature, lipase concentration, and reaction time were screened. The selected conditions were determined as follows: Novozym® 435 (Novozymes A/S, Bagsvaerd, Denmark) as biocatalyst at 8 wt%, substrate ratio (DHA-rich microbial TAG/glycerol) of 1:1 mol/mol, temperature of 50 °C, and reaction time of 12 hours. Under these conditions, the triacylglycerol (TAG), DAG, and monoacylglycerol (MAG) contents in the product were 36.4%, 48.2%, and 15.4%, respectively. The lipase was reused successively for 18 cycles without significant loss of activity under the conditions given above. Fatty acid composition analysis of the final product showed that the contents of DHA in TAG, DAG, and MAG were 53.9%, 44.9%, and 34.8%, respectively. DHA-rich DAG has the potential to be used as an ingredient in infant formula to increase the bioavailability of DHA.     

Synthesis of a novel char-forming agent (PEIC): Improvement in flame retardancy,thermal stability,and smoke suppression for intumescent flame-retardant polypropylene composites

A novel char-forming agent named PEIC was designed and synthesized combining pentaerythritol octahydrogen tetraphosphate (PEPA) and tris(2-hydroxyethyl) isocyanurate. PEIC was combined with the silica-gel-microencapsulated ammonium polyphosphate (OS-MCAPP), preparing intumescent flame-retardant polypropylene (PP) composites. The results of the limiting oxygen index (LOI) show that the composite containing 30 wt % IFR with OS-MCAPP:PEIC = 2:1 presents the optimal LOI of 32.7%. Meanwhile, the cone calorimeter tests show that its peak heat release rate is 432 kW m⁻², which decreases by 62.1% compared with that of pure PP, showing a high-efficient flame retardancy. The exhibited UL-94 V-0 rating for all the composites indicates that the IFR composed of PEIC and OS-MCAPP has high-efficient flame retardancy in PP. The analysis of residue char reveals that PEIC could improve the quality of char in compactness, intumescentia, and the degree of graphitization. Further, the effect of IFR on the mechanical properties of PP composites was also evaluated and discussed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48296.     

大颗粒超高纯度硅溶胶的制备及其表征(英文)

采用新工艺路线制备四乙氧基硅烷（tetraethoxysilane,TEOS）,以TEOS为原料制备超纯度大颗粒硅溶胶。TEOS是烷氧基硅烷法制备甲硅烷的副产物,经过精馏提纯以后,加入盐酸或氨水催化剂,采用溶胶-凝胶法制备硅溶胶。结果表明：TEOS和硅溶胶金属杂质离子总含量都低于0.3mg/L。用盐酸催化TEOS水解制备溶胶,胶粒直径达到129nm;用氨水催化,胶粒直径达272nm。当物质的量比n（C2H5OH）/n（TEOS）=6,n（H2O）/n（TEOS）=5,搅拌速度为250 r/min,制备的硅溶胶胶粒均匀度最好。加水不搅拌,胶粒很容易发生团聚,但是,当搅拌速率高于500 r/min时,胶粒出现团聚现象。     

复合金属氧化物脱硫剂还原法再生机理

利用热天平测试了ＣＯ、Ｈ２还原饱和脱硫剂微孔内Ｆｅ２（ＳＯ４）３的起始反应温度及还原速率，用Ｘ射线衍射法分析了反应中间产物及最终产物．实验结果表明，脱硫剂还原法再生的反应温度较传统热分解法低约２００℃，ＣＯ作再生脱硫剂的还原气体优于Ｈ２，ＣＯ还原脱硫剂内Ｆｅ２（ＳＯ４）３的反应级数为０．８７，活化能为１４２．９ｋＪ／ｍｏｌ．     

DMBR-IVCW耦合工艺处理生活污水的研究

进行了1种新型的动态膜生物反应器(DMBR)和复合垂直流人工湿地(IVCW)的耦合工艺处理生活污水的研究。结果表明,3个阶段耦合系统对COD的去除率分别为90.34%、93.35%和93.68%,对TN去除率分别为93.84%、89.77%和85.13%,对TP去除率分别为85.36%、87.99%和90.39%,对浊度去除率分别为86.74%、97.30%和98.60%。各项出水指标均达到GB18918-2002一级A排放要求和CJ25.1-89要求,可作中水回用。DMBR单元可以有效去除COD以及浊度,同时在抗击污染负荷和水力负荷方面也有稳定表现;而IVCW作为DMBR的生物强化单元,主要是去除N、P等营养物质。     

Synergistic Effects of Nanoporous Nickel Phosphates VSB-1 on an Intumescent Flame-Retardant Low-Density Polyethylene (LDPE) System

Nanoporous nickel phosphates VSB-1 was synthesized by hydrothermal method, and its structure was characterized by X-ray diffraction (XRD), thermogravimetric analyses (TGA) and high resolution transmission electron microscopy (HRTEM). The flame retardancy and thermal behaviour of intumescent flame retardants (IFR) with and without VSB-1 for low-density polyethylene (LDPE) were evaluated by LOI, UL-94 burning test, TGA and cone calorimeter test. With the addition of 2 wt% VSB-1 to LDPE/IFR systems, the LOI value increases from 28.7 to 31, and UL-94 rating raises from V-1 rating to V-0 rating. The results of cone calorimeter show that heat release rate (HRR) peak decrease substantially from 511 KW/m² to 407 KW/m² with 2 wt% VSB-1 in LDPE/IFR systems. The scanning electron microscopy (SEM) indicates the quality of char forming of LDPE/IFR/ VSB-1 is superior to that of LDPE/IFR.     

马来海松酸聚酯多元醇的制备及性能研究

利用松香改性多元酸马来海松酸合成了马来海松酸聚酯多元醇(MAPP),考察了制备MAPP过程中的诸多影响因素,包括催化剂种类和用量、常压下反应时间、二元醇的种类、反应温度以及醇酸的物质的量比、减压反应时间等,并对制备产品的相对分子质量进行了高效凝胶色谱(GPC)表征。最终得出制备高性能MAPP的最优方案,即反应物在常压下于220℃反应4 h,催化剂选择0.10%(质量分数)氧化锌、在减压下反应3 h、n(二甘醇)∶n(马来海松酸)为1.20。利用所研制的MAPP制备的水性聚氨酯(WPU)具有更高的硬度、更强的拉伸强度和更好的耐水性。