水中暂时硬度检测方法适用性研究

针对地表水、自来水、钢铁污水(包括原水和经过石灰处理后的水)等水样,通过碱度法、煮沸法两种不同的方法检测水样中的暂时硬度,根据实验结果及理论知识,分析两种检测方法对不同水样的适用性。结果表明:碱度法、煮沸法对地表水、天然水等较为洁净的水体都适用;对污水等成分较为复杂的水体,煮沸法较为适用,而碱度法则不适用。     

静电纺聚乳酸及其复合材料的研究及应用

聚乳酸及其复合材料作为绿色生物材料,由于其良好的生物相容性和可降解性,在组织工程支架、药物控释体系等领域得到了广泛的应用.静电纺丝技术制备的聚乳酸膜具有孔隙率高、比表面积大等特点.通过对聚乳酸的共聚物或与其他生物材料的共混物进行静电纺丝,改善了聚乳酸亲水性差、降解酸性和降解周期不易控制的缺点,进一步扩大了聚乳酸在药物缓释体系中的应用.本文简要介绍了静电纺丝技术的原理和发展,重点描述了聚乳酸及其复合材料的静电纺丝及其在药物缓释体系中的应用.     

Effect of the matrix resin structure on the mechanical properties and braking performance of organic brake pads

Two chemically modified phenolic resins (PFs) designed and developed for the matrix resins of organic friction materials were characterized. The braking performance of organic brake pads based on the two modified resins and reinforced with hybrid fibers was investigated on a full‐scale test bench. The results indicate that the modified PF with more internal friction units possessed much higher impact and compression strengths, greater toughness, and better braking stability. We concluded that the matrix resin with more adjustable structural units allowed for an adjustable Young's modulus and dynamic mechanical properties and, hence, could indirectly allow an adjustable friction coefficient for organic brake pads during braking process and, furthermore, enable the optimization of braking stability of the friction couples. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012     

动量传递、热量传递和质量传递中的化简分析拓广法及其类似律

采用化简分析拓广法讨论了三传中的问题,一些实验数据已被用于这些过程中的主要参数回归;同时,三传中的类似率也被用于这些参数的计算.     

基于污泥减排的A~2/O-MBR工艺除磷效果研究

以沉砂池出水为研究对象,采用A2/O-MBR组合工艺,对混合型城市污水进行中试研究,考察了该工艺在高效除磷和污泥减排方面的优势,并分析了除磷影响因素。结果表明,系统正常运行情况下,TP的平均去除率为93.83%,最高去除率可达98.21%,出水TP优于城镇污水处理厂污染物排放标准(GB 18918-2002)一级A标准;系统的COD平均污泥产率为0.22 kg/kg,低于常规除磷工艺的COD污泥产率即0.60 kg/kg,实现了剩余污泥减排。厌氧区硝酸盐质量浓度升高会导致TP去除效果下降,当回流比为2时TP的去除效果稳定而且平均去除率最高,而进水COD(<1 000 mg/L)的增减与TP去除率的增减基本趋于一致,试验期间温度、pH等对除磷效果无明显影响。     

顶空气相色谱法测定延胡索酸泰妙菌素中有机溶剂残留量

采用顶空气相色谱法,测定延胡索酸泰妙菌素原料药中甲醇和乙酸乙酯有机溶剂的残留量。结果表明,甲醇和乙酸乙酯在设定范围内有较好的线性,其r值分别为0.9999和0.9998,平均回收率分别为100.1%和99.6%,相对标准偏差分别为1.12%、1.07%。该方法灵敏准确,重现性好,适用于延胡索酸泰妙菌素原料药中有机溶剂残留量的测定。     

高硅含量硅-苯丙乳液的合成及性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、苯乙烯(St)为主要原料,以乙烯基三甲氧基硅烷(A-171)为改性单体,以烯丙基聚乙氧基磺酸盐(SE - 10N)和十二烷基苯磺酸钠(DSB)为混合乳化剂,采用水溶性引发剂过硫酸铵(APS)和亚硫酸氢钠(SBS)与油溶性引发剂偶氮二异丁腈(AIBN)2种引发体系相配合的方式,通过烷氧基硅烷和苯乙烯混合单体对丙烯酸酯种子乳液先渗透溶胀,再进行聚合的方法(单体渗透法)合成了A - 171含量高达50％的硅-苯丙乳液.利用傅里叶变换红外光谱仪对聚合物结构进行了分析,证明了A-171的引入,通过透射电子显微镜(TEM)对粒子形态、粒径分布进行了表征,用原子力显微镜(AFM)、扫描电子显微镜(SEM)相结合的方法对乳液的成膜性能以及成膜助剂的作用进行了分析.最后通过性能测试证明,A -171含量的提高有利于降低涂膜的吸水率,增强涂膜的热稳定性.     

微波水热法制备纳米Fe3O4粉体

通过微波水热法制备了纳米Fe3O4颗粒,并对其进行了Ostwald熟化处理。研究了油酸和氢氧化钠含量对纳米Fe3O4粒径大小以及分散性的影响。利用XRD、TEM等方式对所制备颗粒的结构、形貌进行了表征,结果表明,所制备的纳米Fe3O4粒子属于反尖晶石结构,通过微波加热未经熟化的纳米Fe3O4粒子结晶度较低,平均粒径为6nm。经过在180℃下熟化8h后,转化为结晶度较高,分散性较好,平均粒径为7nm的纳米Fe3O4颗粒。     

Physicochemical Properties,Chemical Composition and Antioxidant Activity of <Emphasis Type="Italic">Dalbergia odorifera</Emphasis> T. Chen Seed Oil

The heartwood or root of Dalbergia odorifera T. Chen is an important traditional medicine in Asia. The aim of the present study was to evaluate the physicochemical properties, chemical composition and antioxidant activity of Dalbergia odorifera T. Chen seed oil. Oil, protein, carbohydrate, moisture, ash and total phenolic contents were found to be 12.96, 26.86, 42.58, 13.70, 3.90 and 5.55%, respectively. Free fatty acids, iodine number, peroxide value, saponification number and unsaponifiable matter were 1.66%, 106.53 g/100 g, 5.07 meq O₂/Kg, 196.78 mg KOH/g and 1.70%, respectively. The oil showed high absorbance in the UV-B and UV-C ranges with potential for use as a broad spectrum UV protectant. The major fatty acids were linoleic acid (60.03%), oleic acid (17.48%) and palmitic acid (16.72%). The total tocopherol, total phenolics and β-carotene were 511.9, 351.1 and 62.2 mg/kg oil, respectively. In addition, the methanol extract of seed oil showed significant in vitro antioxidant activity in four assays including DPPH radical scavenging activity, reducing power, linoleic acid peroxidation inhibition and chelating activity. This study suggests that Dalbergia odorifera T. Chen seed oil has the potential to be used in new products in the functional food, cosmetic or pharmaceutical industries.     

药对款冬花、紫菀及其单味药中挥发油的GC-MS分析

为比较款冬花与紫菀配伍前后挥发油成分的变化,采用水蒸气蒸馏分别对药对款冬花-紫菀及单味药挥发油进行了提取,并结合GC-MS-计算机检索技术对所得样品化学成分进行了分离和结构鉴定,用峰面积归一法测定各组分的相对质量分数。结果表明,从药对款冬花-紫菀、款冬花和紫菀挥发油分别鉴定了37、31和32个色谱峰,各占挥发油总峰面积的96.48%、88.47%和91.61%。药对产生4种新的化合物,而且它们共有成分配伍前后含量也有所改变。