Preparation and properties of nanosize MnZn ferrite from δ-FeOOH

Ferrous ion was transformed into feroxyhyte (δ-FeOOH) by oxidation. Then, manganese sulfate and zinc sulfate in some ratio were added to the feroxyhyte solution. The co-precipitation was boiling reflux conditions sometime under constant stirring. The nanosize MnZn ferrite powder was formed. The mechanism of preparation of the nanosize MnZn ferrite was discussed, and the formation of feroxyhyte which was playing a key role during the process was mentioned. The properties of powder was tested by means of X-ray diffraction, transmission electron microscopy and vibrating sample magnetometer. The results show that the samples of spherical particles about 20 nm, which have characteristics of ferrimagnetism, has larger saturation magnetization, but the remanent magnetization and coercivity are comparatively smaller. The spinel MnZn ferrite nanosize powder was successfully prepared from δ-FeOOH at low temperature, with low-carbon steel and peroxide as main material.     

稳定态二氧化氯杀菌剂的制备及应用

稳定态二氧化氯(C1O2)是一新型杀菌消毒剂，具有高效、广谱、安全的特性，适用范围广，不产生对人体有害物质。介绍了稳定态ClO2的性质、检测、制备条件及其在有关领域的应用。     

多孔β-TCP陶瓷药物载体的制备与体外释药速率的研究

本文用注浆成形的方法制备了以β-TCP为主晶相的多孔药物载体，体外测定了利福平的释药速率。实验结果表明，利福平在模拟体液中能够达到稳定的释放，可以作为骨结核手术后的辅助治疗。多孔β-TCP药物载体有望成为一种理想的药物缓释载体。     

扩链剂在PVC树脂生产中的应用

讨论了常见扩链剂的功能及在聚氯乙烯树脂生产中的应用。     

Effect of cobalt oxide on surface structure of alumina supported molybdena catalysts studied by in situ Raman spectroscopy

A set of Co promoted 10% Mo/Al₂O₃ samples have been characterized by means of Raman spectroscopy under ambient as well as in situ dehydrated conditions. Under ambient conditions, the degree of the polymerization of surface molybdenum oxide species decreases with increasing Co loading. Under dehydrated conditions, the polymeric molybdenum oxide species is absent with the addition of only 0.2% Co. At low Co loadings (2%), before the formation of CoMoO₄ compound, the spectral features are very similar under ambient conditions. Dehydration causes the upward shift of the Mo=O symmetric stretching mode. A broad band around 920–930 cm^–1 was thus observed. This band has been suggested to be associated with the Co-Mo interaction species. In contrast to crystalline CoMoO₄, this species shows a reversibility on H₂ reduction-O₂ reoxidation treatments. From the results obtained, it is proposed that cobalt oxide interacts with the most polymerized molybdenum oxide species to form Co-Mo interaction species and/or crystalline CoMoO₄; therefore, the amount of the surface molybdenum oxide species decreases with a change in the molecular structure as a function of the Co concentration.     

用瞬时法测定液体导热系数

以珠状热敏电阻为加热元件,建立了用瞬时法测定液体导热系数的装置,在25℃下用乙二醇等7个标准样品,对该装置进行了标定,平均偏差为2%.为了核实装置和所得关系式的可靠性,又测定了13个已知导热系数的样品,多数偏差在2%以内,最大偏差为5%.单次测量的精度为0.2%.本文叙述了这一方法的原理,并对实验结果进行了讨论.     

甲苯三氧化硫磺化反应抑制副产物二甲苯砜的研究

对SO3磺化甲苯反应的副产物二甲苯砜成因及反应历程进行了分析,通过实验比较了醋酸与二甲苯砜的抑制效果,提出用磺化副产物二甲苯砜自身抑制的新方法.考察了二甲苯砜力入量和甲苯转化率对抑制副反应的影响.反应温度:10℃,三氧化硫:6%,甲苯转化率为35%时,外加甲苯质量3.3%的二甲苯砜就能控制二甲苯砜含量不增加,且甲苯磺酸异构体的对位含量由84%上升到89%,间位含量由2.5%下降到1%.     

Rheological properties of mixtures of molten polymer and fluorocarbon blowing agent. I. Mixtures of low-density polyethylene and fluorocarbon blowing agent

The viscosities of mixtures of low-density polyethylene and fluorocarbon blowing agent were determined from the measurement of wall normal stress along the longitudinal axis of a capillary die. For the study, three different grades of commercial high-pressure low-density polyethylene were used, together with the following fluorocarbon blowing agents, dichlorodifluoromethane (FC-12), dichlorotetrafluoroethane (FC-114), and blends of FC-12 and FC-114. In the experiment, blowing agent concentration and melt temperature were varied for each combination of polymer and blowing agent employed. Analysis of the experimental data has led to a correlation between the viscosity reduction factor (VRF) and the blowing agent concentration, in which VRF is defined as the ratio of the viscosity of polymer-blowing agent mixture to that of the polymer alone. It was found that the correlation obtained is independent of shear rate and temperature and dependent upon only the type of fluorocarbon blowing agent. The practical significance of the correlation is discussed. We have shown that the entrance pressure drop obtained in the absence of phase separation in the entrance region may be used as a measure of the elastic properties of mixtures of fluorocarbon blowing agent and low-density polyethylene resin.     

Study of collective user behaviour in Twitter: a fuzzy approach

The study of collective user behaviours in social networking sites has become an increasing important topic in social media mining. Understanding such behaviours has its potential to extract actionable patterns that can be beneficial to develop effective marketing strategies, optimise user experiences and maximise website revenues. With the rapid development of micro-blogging, Twitter has become a richer source of intelligence that can be used to study collective user behaviour, due to its efficient and meaningful user-to-user interactions. However, the classical statistical methods have some drawbacks in bridging the gap between user-generated data and human analysts who mostly use linguistic terms to analyse data and model/summarise knowledge learned. To address this gap, this work proposes a new approach, which employs the mass assignment theory-based fuzzy association rules algorithm (MASS-FARM), for the first time, to extract useful interaction behaviour of Twitter users. The influential factors (including activity time, number of friends/followers and the number of tweets) are represented as fuzzy granules, and the associations amongst are studied by employing MASS-FARM. The collective user behaviours are analysed in the Reply category and the Non-Reply category, respectively. The applicability and usefulness of the proposed method are demonstrated via an empirical study on a collected Twitter data set. The derived results are also discussed and compared with existing works.