Evaluating time to maximum rate (TMR) and self-accelerating decomposition temperature (SADT) of self-polymerizing vinyl acetate monomer

Vinyl acetate monomer (VAM) is widely used as a chemical intermediate producing a variety of copolymer products. Besides, VAM has the tendency to readily decompose into free radicals and ions that initiates the self-sustaining polymerization reaction. The non-isothermal experiments of VAM were performed using differential scanning calorimetry (DSC), and the calculations of the kinetic parameters from temperature-programmed DSC curves have been evaluated by the isoconversional method. The thermal analysis of VAM was proceeded using the advanced thermal analysis software (AKTS) to figure out the time to maximum rate (TMR) and self-accelerating decomposition temperature (SADT) for a proactive safety design of VAM. Subsequently, the kinetic model is used to predict the potential thermal runaway in the VAM-PVAc polymerizing process.     

Physical,Mechanical, and Morphological Characteristics of Extruded Starch Acetate Foams

Starch acetates with degrees of substitution (DS) of 0.57, 1.11, 1.68, and 2.23 were prepared and extruded with either water or ethanol. The microstructure, physical properties (radial expansion ratio [RER] and unit density), mechanical properties (spring index [SI] and compressibility), and crystalline structure of the foams were investigated. The functional properties were a function of DS and blowing agent type. When water was used as the blowing agent and DS increased, the foams were pale yellow, with rough and uneven surfaces. The cells were dense, with thick cell walls. Lower RER and SI, with higher DS, were associated with high unit density and compressibility. When ethanol was used as the blowing agent, contrary results were observed. The snow-white foams had smooth surfaces, uniform cells, and smooth cell walls. High RER and SI, and low unit density and compressibility were observed. The changes in SI and compressibility with RER also were examined and found to depend on the type of solvent. A crystalline pattern was observed because of the formation of well-ordered structures during extrusion.     

苯砜基化合物溶解度和分配系数的测定与估算

本文应用线溶剂化能相关法研究了３２种类砜基化合物的溶解度及分配系数与溶剂化显色参数之间的相关性，结果表明，溶解度和分配系数与溶剂化显色参数呈良好的线性关系，测定值与估算值吻合得很好。     

Biodegradability of blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with cellulose acetate esters in activated sludge

Blends of the bacterially produced polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with cellulose acetate esters (CAE) further substituted with propionyl or butyryl groups (degree of substitution: 2.60 propionyl and 0.36 acetyl or 2.59 butyryl and 0.36 acetyl, respectively) were exposed for 4 months to activated sludge to determine their biodegradability. Samples of such blends made by solution-mixing and solvent-casting had complex morphologies in which both individual components as well as a miscible blend phase were present. Additionally, the two opposite surfaces of solvent-cast films showed both physical and chemical differences. After 2 months, samples of pure PHBV had degraded by more than 98% (15 mg/cm² of surface area), whereas a pure CAE sample had degraded less than 1% (<0.2 mg/cm²). Samples containing 25% CAE lost less than 40% of their initial weights (6 mg/cm²) over the total 4-month period. Samples with 50% CAE lost up to 16% weight (2 mg/cm²), whereas those containing 75% CAE lost only slightly more weight than corresponding sterile control samples (1 mg/cm²). NMR results confirm that weight loss from samples containing 25% CAE resulted only from degradation of PHBV and that the surface of samples became enriched in CAE. Solvent-cast film samples containing equal amounts of PHBV and CAE degraded preferentially on the surface which formed at the polymer-air interface. Scanning electron microscopy and attenuated total reflectance infrared spectroscopy revealed this surface to have a rougher texture and a greater PHBV content.     

不同碳源加强A~2/O工艺脱氮除磷效果的研究

以人工配制的模拟城市污水为试验用水,采用76L的A~2/O反应器,以甲醇、乙酸钠和剩余污泥水解酸化液分别作为唯一碳源,研究了进水碳源类型对脱氮除磷和代谢过程的影响。结果表明:以甲醇为碳源时COD的去除率最高为97.04%;以乙酸钠为碳源时NH+4-N的去除率最高为99.5%,TP的去除率最高为95.91%;以酸化液为碳源时TN的去除率最高为70.18%。剩余污泥水解酸化液对脱氮除磷的影响效果不及甲醇和乙酸钠,但是以酸化液作为碳源不仅成本较低,还可实现废物资源化。综合考虑酸化液作为碳源最佳。     

在添加醋酸钾的营养富集培养基中培养杂交瘤细胞(英)

营养富集、添加醋酸钾和灌注培养都是改善杂交瘤细胞培养的策略在Cp9B细胞的静止分批培养中，添加氨基酸和维生素延长了培养时间，但对最大细胞密度影响不大，在反应器分批培养中，营养物明显促进细胞增殖，最大细胞密度比原来提高35倍．利用添加1g／L醋酸钾的反应器灌注培养实验说明，从普通培养基转到营养富集培养基，反应器中的平均细胞密度、抗体浓度和抗体滴度得到了进一步的提高，在培养上清中，乳酸、氨和丙氨酸大量积累，葡萄糖和某些氨基酸大量消耗，以致于可能造成对细胞生长和代谢的抑制。     

二氧化硫和铅联合染毒对小鼠遗传物质的损伤

运用单细胞凝胶电泳技术研究了SO₂和醋酸铅亚急性联合染毒对雄性小鼠脑、肺、脾、肾细胞DNA的损伤.结果表明,在42mg/m³ SO₂和0.2%醋酸铅单独及联合作用下,小鼠脑、肺、肾、脾细胞DNA迁移距离均比对照组显著增加,而且铅可以加剧SO₂对脑、肾、脾细胞核DNA的损伤程度;SO₂对肺细胞核DNA的损伤程度要比铅的损伤大,小鼠肺细胞核DNA迁移距离在SO₂和醋酸铅联合作用组与醋酸铅单独作用组间有极显著性差异(P<0.01),而与SO₂单独作用组间没有显著性差异.SO₂和醋酸铅均可引起小鼠组织细胞的DNA损伤,它们对脑、肺、脾、肾的损伤程度不同,在一定条件下存在明显的协同效应,可以增强彼此的毒性作用.这意味着SO₂和铅均有引起哺乳动物细胞基因突变的潜在危险,大气SO₂污染与铅的污染可能加剧某些疾病的发生与发展.     

第一菊酸乙酯生产废水处理

采用“Fenton反应好氧生物接触氧化”工艺处理第一菊酸乙酯生产废水,确定了处理单元的设计参数;该工艺的CODCr、硝基苯、苯胺去除率分别为94%、78%、83%,出水水质符合(GB89781996)二级排放标准,实际运行效果稳定,运行成本适中,工程造价合理。     

气相色谱法同时测定空气中乙酸甲西旨和乙酸乙酯

建立了用气相色谱法测定空气中乙酸甲酯和乙酸乙酯的方法。本方法前处理简便,分离度好,干扰少,分析灵敏度高,有机试剂使用量少,满足环境分析要求。     

1株异养反硝化硫细菌的分离鉴定及代谢特性

工业废水中的有机物、硫化物和含氮化合物是废水处理面临的重大挑战.利用生物技术,可以实现在废水处理系统中同时去除这3种污染物.在污水处理反应器中,分离出1株异养反硝化硫细菌HDD1.基于16S rRNA基因的系统进化分析和生理特征显示菌株HDD1为Thauera属的一个种.菌株HDD1能够利用乙酸盐和硫化物作为电子供体,硝酸盐作为电子受体进行呼吸作用.在15h之内,CH3COO-(300 mg·L~(-1))、S2-(200 mg·L~(-1))和NO-3(487 mg·L~(-1))被完全代谢去除.扫描电子显微镜和能量色散谱结果显示硫化物氧化的主要产物为单质硫.菌株HDD1能够同时应用于工业废水处理和硫元素的资源化回收.