Separation of the anthracene fraction of coal tar study of as a polyazeotropic mixture

The structural model of anthracene fraction 1 from coal tar is analyzed. That model contains the basic components of the fraction. The constraints on the isolation of individual components by rectification are identified.     

锑尾矿粉基复合胶凝材料的制备及水化特性

以锑尾矿微粉作为主要原料,辅以水泥熟料、活化剂和促凝剂制备锑尾矿粉基复合胶凝材料,并从力学性能及微观结构等方面对复合胶凝材料的水化特性进行探究.结果表明,试件浆体的抗压强度随着锑尾矿微粉掺量的增加而减小,质量掺量为70％时仍满足尾矿固化筑坝要求.不同活化剂对复合胶凝材料强度的影响显著不同,当掺入磷石膏和生石灰且其质量比...     

离心渗铸充型过程中伴随有瞬态固化与再熔现象的流场变化规律

针对离心渗铸工艺中熔体浇注温度太高会带来铸件冶金质量下降问题,在充型过程中一般会发生金属熔液的瞬态固化与再熔现象,建立了旋转多孔介质内伴随有瞬态固化与再熔现象的渗流传热理论模型.通过理论分析获得了离心渗铸充型过程中瞬态压力分布计算公式,建立了不同区域界面的移动速率与温度间的耦合关系,分析了流场变化规律.结果表明：渗透前沿界面推移速度主要受离心渗透压力即渗透动力学因素的影响,而再熔界面推移速度主要受热导率和金属相变特性即材料热力学因素的影响,多孔预型体内发生的瞬态固化与再熔是决定充形过程中渗铸复合层能达到的最大厚度的重要因素.     

神府煤甲醇萃取物的GC/MS及FTIR分析

用GC/MS和FTIR技术结合气相色谱外标定量分析方法,对神府煤甲醇萃取物进行了定性和定量分析,讨论了神府煤甲醇萃取物的化学组成及其结构特征.结果显示,神府煤甲醇萃取物的GC/MS可测组分主要由多环芳烃和含氧化合物组成,其中芳烃以2～3环的烷基取代稠环芳烃为主,含氧化合物中以酮类和酯类化合物居多;结果还检测到种类较多的含氮化合物和少量的含硫、磷、氯的化合物.GC/MS不可测组分的IR分析显示,其中主要官能团有各类羟基、羰基、芳环和亚甲基、甲基等,表明其中可能存在分子量较大的稠环芳香族或其酚、酸、酮、酯类及烷基衍生物的化合物.     

Identification of Carbonyl Compounds in Transesterified Fats Detection in Milk Fat

The non-glyceridic fraction of fats transesterified in the presence of Na-K alloy, and the unsaponifiable fraction of these fats were studied by chromatographic methods. α-Diketones derived from the fatty acids components have been found to be the main by-products of the non-glyceridic fraction, mono-ketones being also present as minor products. These α-dike tones are destroyed during alkaline hydrolysis and when the unsaponifiable fraction is studied, monoketones are found as the main components. On the basis of these findings a method for detecting transesterified fats in natural fats, particularly in milk fat, is proposed.     

FC-20多产低凝清洁柴油加氢裂化催化剂的研制

FC-20催化剂是为满足国内北方市场对清洁低凝柴油的需求而开发的新一代高中油型加氢裂化催化剂。该催化剂以新型小晶粒改性β分子筛和纳米颗粒的无定形硅铝为主要酸性裂化组分,以金属钨镍为加氢组分,采用液相辅助混合技术制备,加氢组分与裂化组分能在催化剂中均匀分散,使得各组分可以充分发挥其催化性能,明显改善了催化剂的加氢性能和异构性能。反应性能研究表明,FC-20催化剂具有裂化活性适宜、加氢性能好、异构性能强、中间馏分油选择性高、柴油与尾油产品低温流动性好等特点,可以实现多产清洁低凝柴油和低倾点优质润滑油基础油原料的目的。     

超临界CO_2萃取铁观音茶叶香气成分

分别采用索氏萃取(SE)、同时蒸馏萃取(SDE)和超临界CO2萃取(SFE)方法提取铁观音的香气成分。用GC/MS分析比较了萃取物中香气成分的组成及质量分数。SDE获得了最多的香气组分,而SFE得到的主要香气成分质量分数和萃取率最高。进一步考察了SFE的压力、温度及夹带剂对主要香气成分的萃取率及质量分数的影响,结果表明随着压力升高香气成分的萃取率及质量分数均升高。而当温度和夹带剂中乙醇质量比为45℃和5%时,总香气成分的萃取率最高,且主要香气成分的质量分数比未添加夹带剂时提高达几十倍,与SFE所得萃取物在香烟中品香评吸的结论完全吻合。     

石墨烯纳米流体相变材料蓄冷特性的数值模拟

鉴于石墨烯高导热性能的特点,将石墨烯纳米流体作为相变材料有望提高蓄冷效率。本文对水基石墨烯纳米流体相变材料的凝固特性进行了数值研究,采用焓-多孔度法追踪固液相界面,分析了石墨烯纳米片质量分数、蓄冷腔体尺寸和几何形状对凝固时间和相界面演化的影响。结果表明,相变材料凝固所需时间随着石墨烯纳米片质量分数的增大显著降低,对于直径为72mm的圆形蓄冷腔体,质量分数为1.2%的石墨烯纳米流体相变材料与去离子水相比凝固时间降低了30.1%,与已有的实验结果相符;随着圆形蓄冷腔体直径减小,石墨烯纳米流体凝固所需时间显著降低,但石墨烯纳米片对凝固的强化作用减弱;在腔体等截面积的情况下,三角形腔体内凝固过程的相界面移动速率明显大于圆形和方形腔体、更有利于促进凝固过程,3种形状腔体内初期凝固都发生在腔体底部、凝固中期相界面形状与腔体本身形状相似、凝固后期相界面趋近于圆形。     

Coarse‐grained models for frontal photopolymerization with evolving conversion profile

We introduce a series of ‘minimal’ models to describe a common light‐driven directional solidification process, known as frontal photopolymerization (FPP ), focusing on experimental observables: the solidification kinetics, light attenuation and spatiotemporal monomer‐to‐polymer conversion. Specifically, we focus on FPP propagation that yields conversion profiles that are not invariant with time, and which cannot be simply described by the presence of mass or heat diffusion. The models are assessed against experimental data for the photopolymerization of a model trimethacrylate system. We find that the simplest model, comprising a single equation of motion for the conversion fraction ? and a generalized Beer–Lambert law, can only describe the experimental data by assuming an unphysical variation in optical absorption. Introducing a ? ‐dependent reaction constant K _eff is found to require a time dependence, regardless of the functional form in ? . We conclude by introducing a ‘minimal’ chemical model, which is based on a simple three‐step reaction scheme involving the spatiotemporal evolution of the photoinitiator fraction, relative fraction of radicals and monomer conversion fraction, that is able to capture the experimental data with a small number of parameters and under reasonable FPP assumptions. Our framework provides important predictive ability for ubiquitous solidification and patterning processes, including three‐dimensional printing, via photopolymerization. © 2017 Society of Chemical Industry     

锕系核素污染沙土的铝热剂SHS固化模拟实验

为探索对锕系核素污染沙土进行玻璃或陶瓷固化的有效途径,采用了铝热剂自蔓延高温合成(SHS)固化的模拟实验.主要进行了铝热剂粉末SHS固化的原理分析、模拟物质的选择、单质铁中模拟物质的含量、固化体中模拟物质浸出率的实验等.结果表明,固化体中模拟元素铈、铒的浸出率为10~(-3)～10~(-5) g·m~(-2)·d~(-1)量级;X射线衍射分析、扫描电镜观察发现,固化体中含有模拟元素铈、铒的硅酸盐晶体,晶体周围分布着大量玻璃体;单质铁相中模拟元素含量极低.用铝热剂可以固化锕系核素污染的沙土.     

Solidification of thermoviscoelastic melts. Part 4: Effects of boundary conditions on shrinkage and residual stresses

The solidification of a molten layer of amorphous thermoplastic between cooled parallel plates is used to model the mechanics of part shrinkage and the buildup of residual stresses in the injection-molding process. Flow effects are neglected, and a thermorheologically simple thermoviscoelastic material model is assumed. The model allows material to be added to fill the space created by the pressure applied during solidification, so that this model can be used to assess packing-pressure effects in injection molding. The interactions between the mold surfaces and the solidifying material are accounted for by modeling different types of constraints through different model boundary conditions. For several sets of boundary conditions, parametric results are presented on the effects of the packing pressure—the pressure applied during solidification to counteract the effects of volumetric shrinkage of the thermoplastic—on the in-plane and through-thickness shrinkages, and on residual stresses in plaque-like geometries. Plaques that can shrink in the in-plane direction while in the mold are shown to shrink more and to have higher residual stresses than plaques that are fully constrained while in the mold. Although the results are presented in terms of normalized variables based on the properties of bisphenol-A polycarbonate, they can be interpreted for other amorphous thermoplastics such as modified polyphenylene oxide, polyetherimide, and acrylonitrile-butadiene-styrene.     

环保型阻燃剂聚磷酸铵合成工艺研究

以尿素和磷酸为原料合成聚磷酸铵,讨论了原料配比、聚合温度、固化温度、固化时间等因素对产品性能的影响。通过实验得出优化工艺条件为：尿素与磷酸的物质的量比为1.7∶1,聚合温度为160 ℃,固化温度为 240 ℃,固化时间为160 min。在该条件下,聚磷酸铵产品五氧化二磷质量分数为68.55%,氮质量分数为13.0%,平均聚合度为35,pH为5.45,阻燃率为65.10%。产品质量符合HG/T 2770-2008工业聚磷酸铵标准。     

Compositions of solvent-extracts of a Polish bituminous coal

The compositions of acetone, tetrahydrofuran and pyridine extracts from a bituminous coal were studied using mass spectrometry and the main components were identified. The compositions of the extracts were similar, as predicted by the electron-donor-acceptor mechanism of coal extraction. Different extract yields are due mainly to differences in the fraction of high molecular weight components in the extracts.     

Crystallization kinetics of the pure triacylglycerols glycerol-1,3-dipalmitate-2-oleate,glycerol-1-palmitate-2-oleate-3-stearate,and glycerol-1,3-distearate-2-oleate

Crystallization kinetics of the three main components of cocoa butter, the triacylglycerols POP, POS, and SOS (where P, O, and S stand for palmitic, oleic, and stearic acids, respectively) were studied by combined differential scanning calorimetry and polarized light microscopy. The morphologies, nucleation kinetics, growth kinetics, and phases of the grains formed were identified with this system. The experimental data, as well as two different models to simulate crystallization and to predict behavior of the pure triacylglycerols, are presented. The first model is based on a macroscopical approach to solidification by using time-temperature-transformation (TTT) diagrams and the additivity principle. It allows prediction of the proportion of the different phases formed for any given thermal path imposed on the sample once the TTT diagram is known for the product. It is illustrated for SOS at constant cooling rates and is compared with experimental results. The second model directly simulates growth of the spherulites in the sample by using nucleation and growth rates that are determined experimentally. It provides a view of the structure as it would be observed with a microscope and shows evolution of the heat released in the sample. Isothermal solidification of POP at 15°C is displayed. The experiment and the model are in good agreement.     

Solidification of glass in molding (a review)

A large number of publications addressing the solidification of glass in molding has been systematized. Different aspects of the effect of the basic composition of glass, diathermancy, time and structural factors on solidification processes are discussed. The workability of glasses and the main conditions for mechanized formation of glass articles are considered as well.     

钛的磷酸阳极氧化工艺

在H3PO4体系中加入不同的钠盐对TA2进行阳极氧化处理.研究表明:电解液组分、pH值、电压、氧化时间等对阳极氧化膜的颜色都有一定的影响,其中电压为影响氧化膜颜色和厚度的主要因素.磷酸盐影响膜的均匀性和连续性,电解液中其他成分主要影响成膜速率,对氧化膜的性能也有一定的影响.     

固化材料在生活垃圾焚烧飞灰处置中的应用概况及前景

焚烧方式因其减量化、无害化等优点将逐步成为我国城市生活垃圾的主要处理方式。飞灰是焚烧方式的主要副产物，其高含量且易浸出的重金属是急需解决的难题。本文从介质固化技术中固化材料的角度系统地总结了国内外的处理现状，展示了水泥、粉煤灰、偏高岭土、赤泥、矿渣、塑料和其他材料在飞灰固化上的应用情况，分别从重金属固化效率以及机械性能等两个主要方面对其固化效果进行评估，分析了各个材料的优缺点，并且给出了工程应用实例和经济性分析。最后在固化材料的工业应用前景和未来发展方向提出了研究建议。     

液体橡胶改性环氧树脂固化及应用研究

用聚丁二烯液体橡胶与环氧树脂制得聚丁二烯液体橡胶/环氧树脂(ETPB)胶粘剂。本文研究ETPB固化剂加入量对粘接和剥离强度的影响。由于该胶粘剂的粘接和剥离性能优异,所以可用于水轮机的耐磨涂层。本文对该胶粘剂在水轮机上的应用性能进行了讨论。结果表明,在ETPB中加入固化剂量为20%时,材料的粘接和剥离性能最好,并且与水轮机用不锈钢性能相比相差不大,可以作为廉价的水轮机叶片保护涂层。     

Deposition of enriched anthracene from the anthracene fraction of coal tar by extractive solidification with <Emphasis Type="Italic">N</Emphasis>-methylpyrrolidone

The deposition of 98.7% anthracene from the anthracene fraction of coal tar by two-stage extractive solidification using N-methylpyrrolidone is considered.     

High-speed melt spinning of bicomponent fibers: Mechanism of fiber structure development in poly(ethylene terephthalate)/polypropylene system

High-speed bicomponent spinning of poly(ethylene terephthalate)(PET)(core) and poly-propylene (PP) (sheath) was carried out and the structure development in the individual components, PET and PP, was investigated. The orientation and crystallinity development in the PET component was enhanced as compared to that of the single-component spinning while the PP component remained in a low orientation state and had a pseudohexagonal crystal structure even at high take-up speeds. To clarify the mutual interaction between the two components in bicomponent spinning, a semiquantitative numerical simulation was performed. The simulation results obtained using the Newtonian fluid model showed that the solidification stress in the PET component was enhanced while that of the PP component was decreased in comparison with the corresponding single-component spinning. This is due to the difference in the temperature dependence of their elongational viscosity. Simulation with an upper-convected Maxwell model as the constitutive equation suggested that significant stress relaxation of the PP component can occur in the spinline if the PET component solidifies earlier than does PP. Based on the structural characterization results, and the simulation results, it was concluded that the difference in the activation energy of the elongational viscosity and solidification temperature between the two polymers are the main factors influencing the mutual interaction in the bicomponent spinning process. © 1996 John Wiley & Sons, Inc.