景德镇高岭村高岭土矿物相的研究

根据对高岭村高岭土样品的X光衍射分析和电子显微镜分析,本文认为:其中脉状高岭土样品的矿物相简单,以多水高岭石为主;而砂状高岭土样品的矿物相较复杂,有高岭石,伊利石,钠长石,白云母和石英等。此外在脉状高岭土样品的电镜分析中,还发现其中多水高岭石大多数呈又粗又短的管状晶形。     

龙岩高岭土的组成与结构研究

本文采用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、激光粒度仪、综合热分析仪(DTA/TG)、场发射扫描电镜(FE-SEM)以及透射电镜(TEM)等测试手段对福建龙岩高岭土进行了组成及结构的研究.结果表明:龙岩高岭土的矿物组成主要由高岭石、多水高岭石和伊利石组成.一定量伊利石的存在是龙岩高岭土的化学组成中含有较高K2O组分的直接原因,这导致其耐火度不高.龙岩高岭土的显微结构为片状和管状混合结构,多水高岭石呈管状,结晶程度最差;高岭石呈不规则薄片状,结晶程度较差;伊利石呈板片状,晶化程度最好.     

超声波法制备高岭石插层复合物

用超声波法制备了高岭石插层复合物.利用红外光谱、X射线衍射和透射电子显微镜分析了不同产地高岭石结构的差异、插层效果以及它们之间的关系.比较了不同类型插层剂与高岭石的插层产物、插层效果及插层机理.结果表明:相同条件下,多水高岭石(埃洛石)和结构压力大的管状高岭石比普通高岭石更易于插层.在60℃,3 h,超声波条件下,将高岭石/二甲基亚砜(dimethylsulphoxide,DMSO)作为媒介,采用两步插层法快速制备高岭石/乙醇前驱体,但DMSO的插层率优于乙醇的.甲醇钠与苏州高岭石作用后,使部分苏州土片层间剥离.     

中国主要类型制瓷高岭土的特征

我国制瓷高岭土分布广泛,开采历史悠久。其主要产区是江苏苏州、湖南界牌、山西大同、广东潮州和江西景德镇。近年来对制瓷高岭土的研究表明,我国北方所产高岭土多属沉积型,矿床赋存于古生代及中生代煤系地层内。南方所产高岭土在成因上则与花岗岩等酸性火成岩有关,多属风化残积型与热液蚀变型。各地高岭土由于成矿地质条件的差别,导致矿石的矿物、化学成分和工艺性能的差别。苏州高岭土的化学成分接近于标准高岭石的理论成分,它的主要矿物成分是高岭石、7多水高岭石和10多水高岭石,特高可塑性和结合性能,焙烧后白度高,耐火度亦高,所以它是制瓷工业重要原料。界牌高岭土的化学成分具征是SiO_2含量高,Al_2O_3、Fe_2O_3含量低,并含少量Na_2和K_2O,它主要由结晶差高岭石、7多水高岭石、白云母、石英和钠长石等组成,其工艺性能特征是细颗粒含量高、焙烧后白度高、耐火度高,但收缩小,因此是制造高档日用细瓷的优质原料。大同高岭土是一种硬质高岭土,其化学成分类似于苏州高岭土,主要矿物成分是高岭石,由于有机质的存在,球磨后具可塑性和成形性能。潮州飞天燕高岭土的化学成分特征是SiO_2高、Al_2O_3低,K_2O比一般高岭土高,它的主要矿物成分是伊利石和高岭石,可塑性中等,焙烧后的白度能达到70—80度,因此可直接用于制瓷。景德镇高岭土的化学成分特征是SiO_2和Fe_2O_3含较高,淘洗后Al_2O_3含量能提高到34—36％,其主要矿物成分是高岭石和7多水高岭石。     

几种高岭土的组成与可塑性研究

采用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、透射电子显微镜(TEM)、激光粒度仪及可塑性仪对龙岩高岭土、临沧高岭土和星子高岭土的组成、结构形貌和可塑性进行了表征.结果表明,龙岩高岭土主要是由片状高岭石和伊利石及管状多水高岭石组成,其结晶度较差,Fe2O3和TiO2含量低,颗粒尺寸最小,d50为5.12 μm,可塑性最好;临沧高岭土则大部分为呈卷曲短柱状的多水高岭石,并含有少量的片状高岭石,颗粒尺寸较小,d50为8.45μm,可塑性差;星子高岭土大部分为片状结构,粒度较粗,d50为14.77 μm,可塑性差.     

我国某地高岭石族矿物形成发展过程在扫描电子显微镜下的研究

在我国某地矿井下发现,该地现在正在形成高岭石族矿物。对此,我们进行了扫描电镜下的研究,系统观察到由水铝英石向高岭石转变的过程,以及靠近石灰岩处局部水铝英石变成蒙脱石的现象。对此我们作如下分析:首先,硅铝岩石遭到酸蚀淋滤,形成硅铝无定形沉淀物(水铝英石),在扫描电镜下呈球粒状及动态析出的丝状物。进而,这些无定形沉淀物发生陈化,原子沿球状及丝状物的表面张力方向,逐渐排列起来,便晶出水埃洛石;水埃洛石进一步脱水而转变成以7(?)为特征的变埃洛石。由变埃洛石转变成高岭石,不仅是管状体的破裂展开,而且有一个形态上和有序度上的质变。这种变化表现为由形态不好的无序高岭石向形态完好的六角板状的有序高岭石转变。我们还观察了沉积岩中的迪开石,这里有趣的是岩屑中的粘土矿物多为高岭石,而岩屑与岩屑之间胶结物则为迪开石。这显然说明,该沉积岩在地下深处具备了形成迪开石的物理化学条件。但为什么异地高岭石却不能转变成迪开石呢?这说明高岭石只通过晶格内部调整转变成迪开石还是困难的。结合我国某地热液成因的迪开石的分析,可以肯定认为,沉积岩中迪开石只能在后生较高的温度压力下由溶液状态结晶出来。文中结合矿区具体地质条件,还讨论了局部蒙脱石形成的机理。     

TiO2/高岭石负载型催化剂的制备与表征

以高岭石颗粒为载体,采用TiCl4水解法制备TiO2/高岭石负载型催化剂。以SEM、IR、XRD、BET方法对其进行了表征。SEM观察到催化剂的表面形貌有了较大的变化,IR、BET结果表明有部分TiO2插入高岭石层间。以草酸为目标降解物考察其光催化活性,结果表明所制得的TiO2/高岭石负载型催化剂的光催化活性比对比样品纳米TiO2高,同时探讨了焙烧温度对催化剂光催化活性的影响。     

丙烯酸树脂及其涂料

含低相对分子质量纤维素混合酯和低相对分子质量含羟基丙烯酸聚合物的低VOC涂料组合物的制备工艺;涂料组合物及形成的多道面涂层;斥水涂料及用斥水涂料涂覆的斥水金属板;镀铬用涂料组合物及含此涂膜的物件;涂料用高固体丙烯酸多元醇树脂组合物     

水分子在高岭石(001)面吸附的密度泛函计算

为研究高岭石(001)面与水分子的相互作用机理,用Material studio 8.0构建了高岭石(001)面的晶体模型,使用GGA-PBE优化高岭石(001)面,分别计算(001)面和含有1、2、4个水分子的分子团吸附构型和平均结合能.结果表明,随着水分子数量的增加,结合能绝对值从35.87 kJ/mol增加到53.94 kJ/mol,复合体系稳定性增加.通过静电势分析可知,高岭石表面主要是负静电势区域略大于正静电势区域.当水分子数量由1个增加到4个时,静电势绝对值较大(>188.18 kJ/mol)的面积由7.99％增加到8.49％,整体静电势水平提高,有利于后续水分子吸附.运用RDG函数,展示了高岭石和水分子之间的弱相互作用,结果表明高岭石和水分子主要通过氢键方式结合.由AIM分析的结果可知,高岭石-水的氢键键能弱于水-水的氢键,当水分子数量增加时,高岭石-水氢键键能会进一步减弱.     

可水分散封闭型多异氰酸酯

英国Baxenden化学品公司以3,5－二甲基吡唑（DMP）为异氰酸酯基团的封闭剂,制得了一种新型的可水分散封闭型多异氰酸酯交联剂TrixeneB17986.它可与含羟基的丙烯酸乳液配制成单组分热固化涂料,这种涂料的最终性能可与溶剂型涂料相比。以DMP封闭的多异氰酸醋的解封闭温度较其它封闭型多异氨酸酯的低,可在120－130℃温度固化。当使用一般的聚氨酯用催化剂时,固化时间为30min;使用该公司一种新型催化剂时,固化时间为10min。该公司的试验表明,使用这种封闭型水分散多异氰酸酯和丙烯酸共聚物乳液可配制高性能涂料。用这种交联剂配制的…     

硼酸钙对铜渣中夹杂铜沉降效果的影响

考察了添加剂CaB2O3对转炉铜渣中夹杂铜沉降效果的影响，并结合铜渣的粘度测试及红外光谱表征，研究其影响机理，采用FactSage软件计算了添加剂对铜渣液相线温度的影响。结果表明，随添加剂含量增大，铜渣中夹杂铜的沉降效果逐渐增强，添加剂含量由0增至6wt%时，底部渣含铜量由4.10wt%增至6.85wt%，这是由于添加剂可有效降低铜渣粘度。随添加剂含量增大，渣粘度降低，但降低效果随温度增大而趋于平缓。随添加剂含量增大，铜渣的硅酸盐结构趋于简化，添加剂通过破坏铜渣复杂的硅酸盐结构降低铜渣粘度。铜渣的液相线温度随添加剂含量增大而减小，添加剂通过减少渣中固体颗粒的方式降低铜渣粘度。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Charakterisierung von Suspensionen nanoskaliger Partikel mittels Ultraschallspektroskopie und elektroakustischer Methoden

Technical control over dispersions with particles in the nanometer size realm should bring about a boost in innovations for some parts of industry. Requirements for the development of these new products is the accurate characterization of the various materials systems. A characterization should always include a determination of the particle size distribution, since it is coupled to the specific effects of these systems. Ultrasound measurement techniques and electroacoustics are two if the available techniques that allow determination of the size distribution and zeta potential of particles with dimensions up to 10 nanometers. A further fundamental advantage of the method is the possibility of carrying out measurements in high‐concentration materials systems. This report describes ultrasound spectroscopy for the measurement of fine‐ and very‐fine‐dispersion particles, and the known theoretical concepts for the interpretation of spectra. In addition, experiences in the use of currently available measurement techniques are presented.     

Trapping the western pine beetle at and near a source of synthetic attractive pheromone Effects of trap size and position

Western pine beetles were caught on unbaited sticky traps placed near a source ofexo-brevicomin, frontalin, and myrcene. Size of trap, distance and direction from the source of attractant, and height from the ground were varied. Significant differences in trap catch were observed in relation to each of the variables. Traps close to the source of attractant caught more beetles than traps farther from the source. Traps downwind of the source of attractant caught more beetles than did upwind traps. More males than females were trapped close to the source of attractant.Based in part on a thesis submitted by the senior author to the University of California, Berkeley, California, in partial fulfillment of the requirements for the degree Master of Science in entomology, December 1976. These studies were supported by the U.S. Forest Service and in part by the Rockefeller Foundation and a joint grant (NSF GB-34718/BMS 75-04223) from the U.S. National Science Foundation and the U.S. Environmental Protection Agency to the University of California. The findings, opinions, and recommendations are not necessarily those of the University of California or the funding agencies.Trade names and commercial enterprises or products are mentioned solely for information and do not constitute endorsement by the U.S. Department of Agriculture or University of California.     

Mechanical Means of Enhancing Drying Rates: Effect on Drying Kinetics and Quality

The effect of various pretreatments on drying kinetics as well as quality parameters of selected vegetables and fruits was studied experimentally in a convective dryer. The pretreatments tested include application of pinholes and drilled holes of different diameters and densities, blanching and freezing. Potato, cassava, dragon fruit and red chilli were used as the sample drying materials. As expected, increase of the diameter and density of the holes under fixed drying conditions increased the drying rate. Samples with drilled holes showed better drying performance than those with pinholes. The improvement of the drying rate was found to be dependent on the physical properties and the initial moisture content of the material. Results show that the drying performance of the products that possess a skin of low moisture diffusivity, such as chilli, can be improved significantly by blanching and making perforations in the skin. Overall changes of color and volume shrinkage during drying of the samples with and without holes were similar. The effect of different modes of heat input, such as convection, conduction and radiation, on the drying performance of the treated samples was also experimentally investigated. On-off type controllers were used to regulate the power of the heaters and maintain the product temperature within a range of pre-set values. Convection combined with radiation displayed the highest drying rate.     

氮气幕对瓦斯爆炸进行阻爆实验

为阻断瓦斯爆炸在管道方向上的传播，保护管道后方区域，本文采用氮气幕来进行阻爆，所设计的实验装置在爆炸发生后能自动喷出氮气。主要研究了氮气的喷气压力和喷气时刻对阻爆功能的影响。结果表明，在喷气压力为0.1MPa时，氮气幕仅起到抑制作用，爆炸火焰能穿过整个实验管道。在喷气压力为0.2MPa时，仅部分实验能够阻爆，氮气幕产生不稳定的阻爆效果。在喷气压力为0.3MPa时，阻爆位置均稳定在左喷头和右喷头之间区域，氮气幕产生稳定地阻爆效果。喷气压力超过0.4MPa后，阻爆位置稳定在右喷头附近。在较低氮气压力0.2MPa下，喷气时刻对阻爆效果产生显著影响。随着喷气时刻延迟，氮气喷出量减小，氮气幕由不稳定阻爆变为不阻爆。喷气时刻延迟到198ms后，氮气幕便丧失阻爆功能。在喷气压力超过0.3MPa后，氮气幕阻爆效果便不受喷气时刻的影响，喷气压力对能否阻爆起决定作用。     

水平及竖直基底上微小固着液滴的蒸发特性分析

为揭示非水平表面上微小蒸发液滴的传热传质特性,本文在准稳态模型的假设下构造三维液滴模型,综合考虑了蒸气扩散、蒸发冷却以及气相域中的自然对流这3种传输机理,对水平以及竖直基底上液滴的蒸发过程进行数值研究。通过分析气液界面上温度分布、蒸发通量分布及总蒸发率的变化,重点探究了基底过热度以及重力的改变对液滴蒸发特性的影响。结果表明：与水平基底上温度的对称分布不同,竖直基底上气液界面温度分布表现出明显的非对称性,且非对称性随基底过热度的升高而增强,最低温度点不再位于液滴顶点,而向一侧偏移。此外,水平基底上气液界面局部蒸发通量呈对称分布,各截面分布相似,而竖直基底上局部蒸发通量分布则呈现出显著的非对称性以及各截面异性,非对称性随着基底过热度的升高而增强,这是重力改变后气相域自然对流发生改变的结果。与水平基底相比,竖直基底上蒸发率更高,总蒸发时间更少。最后,基底由水平变为竖直时,液滴内部流场由对称双涡转变为非对称单涡,单涡流速显著大于双涡流速,液滴内流速随基底过热度的上升而增大,单涡环流造成了气液界面温度分布的改变以及最低温度点的偏移。     

Kinetics of base-catalyzed transesterification of triglycerides from Pongamia oil

The kinetics of transesterification of Pongamia oil using methanol at 60°C were studied. The forward as well as the reverse rate constants of all three steps involved in the transesterification of Pongamia oil are reported for the first time. Among the forward rate constants, the one governing the conversion of TG to DG was the highest and the one for DG to MG was the lowest. A distinct feature of the present work is the direct estimation of the equilibrium constants of all three steps by measuring the concentrations of TG, DG, and MG at very long reaction times. This reduced the number of parameters to be, determined from the kinetic data by one-half, thereby leading to more accurate estimation of the rate constants. The equilibrium constant of the final step involving the conversion of MG to methyl ester and glycerol was at least an order of magnitude greater than that of the first two reaction steps. A detailed comparison was made with kinetic parameters reported in literature. The trend in the relative magnitudes of the rate constants appears to be unique to Pongamia oil.     

Breakage patterns of agglomerates

The experimental information available in the literature regarding the patterns of breakage of agglomerate materials is scarce, particularly in dynamic loading. The primary objective of this paper is to present our findings on the breakage patterns of the agglomerates and the interparticle bond. A high-speed digital video imaging technique is used here to gain an insight into the impact behaviour of individual agglomerates against a target plate. Several breakage patterns are observed. Agglomerates may suffer localised damage only, with the disintegration of the damaged zone into very fine debris, or localised damage combined with fracture. The frequency of occurrence of these patterns depends on the impact velocity and agglomerate structure. The pattern of breakage affects significantly the size distribution of the impact product. An investigation of the breakage of individual interparticle bonds is also presented. Two forms of failure are observed, internal (cohesive) and interfacial (adhesive) failure. The morphology of the fractured surface depends greatly on the type of breakage. Internal breakage shows irregular surfaces due to crack jumping, whereas interfacial failure produces clean, smooth fracture surfaces. These observations should provide the necessary foundation for the development of a fundamental model of agglomerate breakage.     

Functional properties of proteins in foods

The measurement of functionality of protein food ingredients has developed somewhat haphazardly, probably due to the wide range of proteins used as ingredients and the diversity of foods. Studies of the physiochemical properties of proteins should enable prediction of a proteins response to process environments and prove more fruitful than many of the empirical measurements of functionality. The effects of pH, salt type and concentration on the phase behaviour of the oilseed globulin and arachin, demonstrates the complexity of protein solubility and the inadequacies of simple tests that have arisen. Studies of the effects of salts and conditioning on meat fibres, coupled with measurement of the location of water in pellets from water holding tests enable the latter to be applied with increased confidence. Comparison of the endothermic transitions observed on heating with the development of storage and loss moduli allow the contributions of domains of skeletal muscle myosin to gel structure to be investigated.