不同类型的预处理对聚胺纳滤膜性能的影响

尽管膜的预处理常用于确保实验数据的可靠性，但是其也有可能改善许多膜的性能。本研究探讨了化学预处理和润湿对膜通量和保留率的影响。结果显示既具有磷酸盐缓冲又具有碱性清洗剂作用的化学预处理能够提高通量并降低保留率。膜清洗后在40℃润湿，可以提高通量和保留率，而在50℃润湿，则会降低通量，提高保留率。观察到使用NaOH，pH为9．8或10．4的预处理没有影响。     

高速离心法对清喉颗粒除杂效果的研究

考察高速离心法对清喉颗粒的除杂效果。以绿原酸、总黄酮、牛蒡子苷保留率及固形物减少率为指标,对离心转速,离心时间,药液比等3因素进行考察。经高速离心法除杂,有效成分的保留率都较高(绿原酸保留率为97.115%,总黄酮的保留率为85.925%,牛蒡子苷保留率为98.039%),但固形物平均减少率为15.963%,达不到大幅度降低服用量的要求。     

绢云母紫外线屏蔽剂在聚丙烯中的应用

研究了绢云母基质紫外线屏蔽剂对GC-1的老化性能和力学性能的影响。氙灯模拟太阳强制光老化研究表明，添加了GC-1可明显改善PP的耐老化性能，机械强度保留率明显提高。其中，拉伸强度保留率由不足50％提高到70％，弯曲强度保留率由79％提高到90％，冲击强度保留率提高一倍。同时GC-1还可以改善PP的机械性能，增韧能力超过常规填料。GC-1在PP中的添加量以20％为最佳。     

检修机车腻子剥离剂开发

以酸和溶剂为主剂制备了系列铁路机车腻子剥离剂,研究了组分组成、浸泡时间和温度等条件对不饱和聚酯腻子质量保留率和压缩强度保留率的影响.结果表明:基于硝酸制备的腻子剥离剂去除效果更优,室温浸渍时间20～30 min后,腻子质量保留率最低为51.8％,压缩强度保留率最低为9.2％.     

不同显色剂对热敏记录材料发色和保存性能的影响

选用酚类显色剂A、B、C和非酚类显色剂D、E,分别与荧烷染料红色素16进行显色反应，经涂布干燥得到热敏记录材料。通过对比发色性能、底色灰雾和白度、保存性能和防水性能等筛选出最佳的显色剂为环保型的非酚类显色剂D。显色剂D组热敏记录材料打印后最大密度可达2.02,且高温高湿下底色几乎无变化，发色保留率和老化发色保留率均可达到90%以上。     

阳离子对渤海某油田聚合物溶液剪切后粘度保留率的影响研究

根据某油田2种不同水质(水源水、污水)对聚合物溶液剪切后粘度保留率的实验结果,分析该油田水源水和污水的主要离子组成差别,研究了阳离子对聚合物溶液剪切后粘度保留率的影响。结果表明,Mg2+对聚合物溶液剪切后粘度保留率影响最大,配制聚合物溶液水质中的Mg2+浓度150 mg/L时,粘度保留率只有45.4%;配制聚合物溶液水质中Ca2+浓度150 mg/L时,聚合物溶液剪切后粘度保留率为60.1%。一价阳离子Na+与二价阳离子Mg2+和Ca2+相比,不是影响聚合物溶液粘度保留率的关键因素,在浓度3 000 mg/L时,聚合物溶液剪切后粘度保留率为69.1%。在理论上对水质中离子种类对聚合物溶液剪切后粘度保留率的影响进行了分析。     

不同压缩比下白炭黑增强氟硅橡胶的老化性能

以白炭黑增强氟硅橡胶为研究对象,考察了不同的压缩率和加速老化温度下材料的压缩永久变形保留率的变化,研究了应力、老化温度等对材料压缩性能保留率的影响,采用同步热分析仪对200℃热空气加速老化环境中材料的热稳定性进行了对比分析。结果表明,相同压缩比下材料的压缩永久变形保留率随温度的升高而下降;同一温度下,压缩比越大材料的自由体积越小,相应的压缩保留率越小;相同压缩比下,温度越高分子链运动能力越强,松弛后的高度越低。热失重分析结果表明,压缩比、老化时间等对材料热性能的影响相对较小,推测是受力状态下在热空气加速老化过程中白炭黑增强氟硅橡胶的分子结构破坏程度较小所致。     

马齿苋提取液脱色的工艺

以马齿苋提取液为原料,考察了脱色剂上柱液体积、洗脱剂乙醇的体积分数及用量等工艺条件及四种脱色剂对脱色效果的影响。通过正交实验,以脱色率、多糖保留率、黄酮保留率为指标,采用紫外可见分光光度法测定,确定了马齿苋提取液脱色的最优工艺为V(上柱液)=3mL、φ(乙醇)=70%、V(乙醇)=12.5mL、洗脱时间2h,该条件下脱色率为67.4%,黄酮保留率为49.8%,多糖保留率为63.1%;最佳脱色剂为AB-8大孔吸附树脂,该脱色工艺简单可行,脱色效果好。     

环己二甲酸型不饱和树脂交联体系的研究

通过光学显微镜、Q型紫外老化试验仪(QUV)分析、老化后树脂泛黄程度和力学性能测试等研究手段考察了分别采用苯乙烯和甲基丙烯酸甲酯代替部分苯乙烯作为由1,4-环己二甲酸(CHDA)制备的新型不饱和聚酯树脂的交联剂的耐候性和力学性能,并将苯乙烯交联体系(CS)和甲基丙烯酸甲酯交联体系(CMS)的耐候性能和力学性能及其保留率进行了比较。结果表明,用甲基丙烯酸甲酯全部取代苯乙烯做交联剂会使树脂固化不完全,甲基丙烯酸甲酯可以部分替代苯乙烯用作交联剂二者最佳质量比1∶1,成型树脂加速老化1000 h后,耐候性能优于纯苯乙烯交联体系,表面不易泛黄,且力学性能保留率较高,冲击强度保留率大于90%,拉伸强度保留率大于60%。     

高耐介质聚天门冬氨酸酯型聚氨酯地坪涂料制备及其力学性能评价

采用聚天门冬氨酸酯与脂肪族异氰酸酯合成聚氨酯材料，对影响聚氨酯性能的交联密度、α值、阻燃剂、耐磨助剂等因素进行研究，并考察了聚氨酯材料的长期耐介质性能。测试发现，通过调节三官能度异氰酸酯含量，可得到兼具较高力学性能和弹性的聚氨酯材料，添加阻燃剂后材料的力学性能和拉伸强度均有所降低，添加少量的微蜡粉可提高材料的耐磨性；同时本材料体系还具有优异的耐介质性能，在水、海水、酸、碱和油等中浸泡10个月后，材料的拉伸强度和断裂伸长率的保留率均大于98%；浸泡20个月后，材料的力学性能保留率基本大于75%。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。