溶胶-凝胶伴随相分离法制备多孔氧化锆块体材料

以无机锆盐氧氯化锆(ZrOCl2·8H2O)为前驱体,聚氧乙烯(PEO,MV=106)为相分离诱导剂,环氧丙烷(PO)为凝胶促进剂,采用溶胶-凝胶伴随相分离制备孔径尺寸可控且骨架连续的多孔氧化锆块体材料,利用扫描电镜、X射线衍射、差热分析等测试手段对所制得块体材料进行了表征。结果表明:PO借助不可逆的开环反应提高体系的pH值,从而促进溶胶体系的凝胶化;PEO则诱导体系发生相分离,并获得共连续多孔块体;ZrO2干凝胶在热处理前呈无定形态,400℃热处理后有四方相晶体出现,800℃热处理后四方相基本都转变为单斜相;热处理所产生的晶型转变基本不影响块体材料的微观形貌。     

Ag/Cu离子双注入ABS树脂抗菌性能研究

采用金属蒸汽真空弧(MEVVA)离子源将银离子和铜离子注入丙烯腈-丁二烯-苯乙烯共聚物(ABS)表面,并通过扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和拉曼光谱(Raman)对该材料进行了表征,同时测试了改性后ABS树脂的抗菌性能。结果表明:离子注入后材料表面被侵蚀,且随着能量的增加粗糙程度变大;离子轰击使材料表面的化学键断裂、易挥发物质释出,并出现富碳层;离子注入后以氧化物的形式存在于材料表面;ABS树脂表面注入银离子和铜离子后具有优良的抗菌效果。     

钛白搪瓷表面银离子扩散工艺研究

目前在抗菌搪瓷方面的研究大多是将银系抗菌剂与搪瓷釉料混合后进行高温烧结成,而通过离子扩散的方式引进银离子的有关报道尚未见到。本论文主要对利用涂覆法在一定热处理温度下在钛白搪瓷表面进行银离子扩散的工艺进行了研究。研究结果表明,采用该工艺制备的搪瓷表面存在银离子的扩散且分布均匀,说明该工艺可行;热处理温度较高时,银离子扩散进入搪瓷表面的量相对较多,但较高的温度,会对搪瓷原来的表面结构产生一定的影响。     

银-钬抗菌白炭黑的合成

本研究采用溶胶-凝胶法合成了一种新型无机抗菌材料-银-钬抗菌白炭黑.与只含有银的抗菌白炭黑相比,这种新型抗菌材料具有更显著的杀菌效果.其对大肠杆菌的杀菌率能达99％以上.通过研究银离子浓度、钬离子浓度和反应时间对杀菌率的影响,得到较理想的制备条件是,银离子浓度0.09 mol·L-1,钬离子浓度0.003 mol·L-1,反应时间2.5h.通过对FTIR图谱的分析,可知银离子和钬离子的添加几乎未改变白炭黑的结构.另外XRD图谱显示该材料为无定形态.     

抗菌剂对滑石粉填充聚丙烯材料基础性能与散发特性的影响

利用熔融共混的方法制备了抗菌滑石粉填充聚丙烯(PP)材料,研究无机银离子抗菌剂含量对滑石粉填充PP材料力学性能、抗菌效果、耐划擦性能、长效抗菌性能和散发特性的影响。结果表明:添加1%(质量分数)的无机银离子抗菌剂,材料弯曲模量和缺口冲击强度略有增加,增加幅度约为5%;当抗菌剂添加质量分数超过0.7%时,抗菌效率均超过99.9%;无机银离子抗菌剂具有良好的耐热性能,对PP材料热氧老化基本无明显影响。当抗菌剂质量分数达到0.7%时,在150℃放置400 h后,该体系抗菌效率仍可以超过99.9%;相对非抗菌材料,抗菌剂对材料耐划擦性能和散发特性无明显影响,且划擦后的抗菌效率超过99.9%;添加抗菌滑石粉填充PP材料的抗菌持久性较好,适合作为健康汽车材料应用。     

银-石墨烯复合材料的原位制备及性能研究

以鳞片石墨为原料,采用Hummers法制备氧化石墨.氧化石墨与硝酸银溶液混合超声处理,通过功能离子预吸附的方式,将银离子有效地分散在氧化石墨烯载体上.以水合肼为还原剂,同时还原氧化石墨和硝酸银溶液中的银离子,原位制备银-石墨烯复合材料.采用X射线衍射仪、扫描电子显微镜对制得的银-石墨烯复合材料进行表征,并对复合材料的电化学性能进行分析.结果显示,制得银-石墨烯复合材料的比电容明显高于单纯的石墨烯材料,电化学性质优异,是理想的电化学电容器电极材料.     

中科院制成抗菌双层聚偏氟乙烯中空纤维膜

<正>近日,中科院宁波材料技术与工程研究所高分子事业部功能膜团队通过双层共挤出技术制备出外层富集抗菌银离子的双层聚偏氟乙烯(PVDF)中空纤维膜。此前,该团队研究人员通过非溶剂诱导辅助热致相分离法已制备出双连续结构的PVDF膜,以及具有良好抗菌性能的中空纤维膜。在此基础上,为了减少     

银离子注入与银/铜离子双注入ABS树脂抗菌性能研究

用金属蒸汽真空弧源(MEVVA)分别对丙烯腈-丁二烯-苯乙烯共聚物(ABS)树脂进行银离子注入与银铜离子双注入,加速电压均为30 kV,注入剂量均为1×1016cm-2。通过抗菌实验表明,银离子注入样品与银铜离子双注入样品均表现出优良的抗菌性能,但银铜离子双注入样品的抗菌性能更加优异。对样品分别进行扫描电子显微镜、拉曼光谱与电子能谱表征,结果表明,离子注入后表面变粗糙,出现无序碳层并伴有富氧,银与铜以离子形式存在。     

掺铒银型无机抗菌材料的制备与研究

利用溶胶-凝胶法制得白炭黑,并在制备时将稀土元素铒和银离子共同掺杂到白炭黑中,得到一种含稀土的新型无机抗菌材料.通过单因素实验得到最佳制备条件为:稀土元素铒浓度0.005 mol·L-,反应温度90℃,反应时间1h.在此条件下利用平板涂布法进行抗菌检测,发现银-铒抗菌白炭黑对大肠杆菌具有很好的杀菌效果,杀菌率达99.38％.采用XRD、FTIR、SEM和EDS等对样品进行表征,结果表明产品为无定形态;稀土铒和金属银的添加并没有明显改变白炭黑原有的结构;实验制备的样品中含有稀土元素铒和金属银,银是附着在载体白炭黑上的,而稀土元素铒则是单独游离在材料中.     

抗菌粉末涂料

以无机氧化物包覆银离子抗菌剂制备的抗菌粉末涂料抑菌效果好、时效长。介绍抗菌添加剂 ,抗菌粉末涂料的涂膜性能及抗菌效果。     

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.     

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。     

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.     

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.     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。     

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…     

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。     

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。