负载氧化锌活性炭对苯的吸附性能及热力学研究

对微波活化处理废触媒制备的活性炭进行了微结构分析,发现活性炭具有孔隙发达,微孔贯穿性好的结构,孔隙中负载了少量的具有催化作用的氧化锌.采用光离子化气相色谱法测定了20℃、30℃和40℃活性炭对苯的吸附等温线,并用Langmuir方程进行了数据拟合,且适合于该方程.同时计算了平均吸附热(△H),吸附自由能(△G),吸附熵...     

Current Opinion in LAIV: A Matter of Parent Virus Choice

Influenza is still a frequent seasonal infection of the upper respiratory tract, which may have deadly consequences, especially for the elderly. This is in spite of the availability of vaccines suggested for persons above 65 years of age. Two types of conventional influenza vaccines are currently licensed for use—live attenuated and inactivated vaccines. Depending on local regulatory requirements, live attenuated vaccines are produced by the reverse genetics technique or by classical reassortment in embryonated chicken eggs. Sometimes, the efficiency of classical reassortment is complicated by certain properties of the wild-type parent virus. Cases of low efficacy of vaccines have been noted, which, among other reasons, may be associated with suboptimal properties of the wild-type parent virus that are not considered when recommendations for influenza vaccine composition are made. Unfortunately, knowledge surrounding the roles of properties of the circulating influenza virus and its impact on the efficacy of the reassortment process, vaccination efficiency, the infectivity of the vaccine candidates, etc., is now scattered in different publications. This review summarizes the main features of the influenza virus that may dramatically affect different aspects of the preparation of egg-derived live attenuated vaccine candidates and their effectiveness. The author expresses her personal view, which may not coincide with the opinion of other experts in the field of influenza vaccines.     

LF精炼过程中炉渣成分对钢水[Ca]含量的影响

根据冶金熔体的共存理论,计算了CaO-MgO-MnO-FeO-SiO2-Al2O3六元渣系各组元的作用浓度。结合生产实际数据,建立了LF精炼过程中炉渣成分和钢水[Ca]之间氧化还原反应的数学模型,计算了炉渣成分对钢水[Ca]含量的影响。结果表明,LF精炼过程中钢水[Ca]含量受[Si]-(FeO)联合控制,渣中SiO2、FeO质量分数每增加1%,[Ca]质量分数分别降低1.63×10-6和1.55×10-6。为了将[Ca]质量分数控制在10×10-6以下,当FeO质量分数为3%左右时,碱度B应不高于0.9。     

沈从文笔下的爱情悲剧与中国古典爱情悲剧之比较

沈从文笔下的湘西世界是优美的,但这些人物所展示的情爱世界却大都是悲剧性的。这些悲剧性的产生,有社会大环境及自然环境的恶劣,封建礼教及旧制度、旧社会陈规陋习的束缚及毒害,也有与青楼女子之间的产生了真正的爱却不能持久,还有不凑巧或因人去世而好梦难圆的悲剧。与中国古典爱情悲剧相比较,沈从文笔下的爱情悲剧有着更加宽广的外延和丰富的内涵。     

ADSORPTION ISOTHERMS AND CATALYST SELECTIVITY FOR A UNIFORM SURFACE: THE ROLE OF MULTIPLE LANDING AREAS

In general a gas phase species can be present simultaneously in more than one adsorbed form on a uniform solid surface. The different adsorbed forms tie up different combinations of surface sites. Each such combination is termed a landing area. The different adsorbed forms present on the surface of a catalyst may form different products. (In the more general case, each different adsorbed form yields a different distribution of a set of products.) Hence the relative amount of each adsorbed form and landing area present on the surface determines the selectivity of the solid catalyst. The variation of the landing area distribution with temperature and partial pressure of the gas phase species is examined in the first part of this work. In general, increasing the pressure or decreasing the temperature leads to the relative decrease of molecules adsorbed on landing areas consisting of larger number of sites and the relative increase of molecules adsorbed on smaller landing areas. The kinetics of metal catalyzed skeletal isomerization and hydrogenoly-sis of hydrocarbons on supported metal catalysts is examined in the framework of the landing area in the second part of this work. A simple model for the variation of reaction order with pressure agrees with experimental data from other laboratories.     

Phase Equilibria of the Sn-Sb Binary System

Sn-Sb alloys are important high-temperature solders. However, inconsistencies are found in the available phase diagrams, and some phase boundaries in the Sn-Sb system have not been determined. Sn-Sb alloys were prepared, equilibrated at 160°C to 300°C, and the equilibrium phases and their compositions were determined. The β-SnSb phase has a very wide compositional homogeneity range, and its composition varies from Sn-47.0at.%Sb to Sn-62.8at.%Sb. There is no order–disorder transformation of the β-SnSb phase. There are three peritectic reactions in the Sn-Sb system, L + Sb = β-SnSb, L + β-SnSb = Sn₃Sb₂, and L + Sn₃Sb₂ = Sn, and their temperatures are 424°C, 323°C, and 243°C, respectively. Thermodynamic models of the Sn-Sb binary system were developed using the CALPHAD approach based on the experimental results of this study and the data in the literature. The calculated phase diagram and thermodynamic properties are in good agreement with the experimental determinations.     

Thermodynamically consistent modeling of elementary electrochemistry in lithium-ion batteries

This paper is particularly concerned with the elementary reactions and transport processes that are responsible for Li-ion battery performance. The model generally follows the widely practiced approach developed by Newman and co-workers (e.g., Doyle et al., J. Electrochem. Soc. 140 (1993) 1526 [1]). However, there are significant departures, especially in modeling electrochemical charge transfer. The present approach introduces systems of microscopically reversible reactions, including both heterogeneous thermal reactions and electrochemical charge-transfer reactions. All reaction rates are evaluated in elementary form, providing a powerful alternative to a Butler-Volmer formalism for the charge-transfer reactions. The paper is particularly concerned with the influence of non-ideal thermodynamics for evaluating reversible potentials as well as charge-transfer rates. The theory and modeling approach establishes a framework for extending chemistry models to incorporate detailed reaction mechanisms that represent multiple competitive reaction pathways.     

相图热力学计算在AM60-XGd镁合金设计中的应用

以相图热力学为基础,计算了Mg-6Al-XGd(质量分数,%,下同)镁合金的垂直截面图,200和500℃的等温截面图。根据相图设计了不同Gd含量的AM60-XGd(X为0%,0.8%,1.2%,1.6%和2.0%)镁合金。并且对不同Gd含量的AM60镁合金进行了显微组织观察、力学性能测试。结果表明,AM60合金组织随着稀土的加入得到细化。合金的抗拉强度和延伸率都得到显著提高。当合金中加入1.6%Gd时,合金表现出最好的显微组织和力学性能。     

Thermal conductivity measurements and molecular association in a series of alcohol vapors: Methanol,ethanol, isopropanol,and t-butanol

Thermal conductivity measurements on the vapors of methanol, ethanol, isopropanol, and t-butanol are reported as a function of temperature (330–420 K) and pressure (11–240 kPa). The thermal conductivity versus pressure isotherms for all four alcohols exhibit upward curvatures at the lower temperatures and nearly linear increases at higher temperatures. This behavior is indicative of a dimeric species and one or more polymeric clusters in the vapor in addition to the monomer. Quantum mechanical calculations have indicated that tetramers are the most likely polymeric species. Detailed analyses of the data provide thermodynamic data (H,S) for the dimerization and tetramerization reactions and show interesting correlations with the size of the monomer unit.     

Modeling a non-equilibrium distillation stage using irreversible thermodynamics

We compare transport equations derived from non-equilibrium thermodynamics to a classical rate model developed over the last 20 years, in terms of their ability to calculate the heat and mass fluxes by modeling a segment of a packed distillation column. We show, using water and ethanol separation as an example, that there is a significant coupling between heat and mass transfer. Neglect of this transport coefficient leads to variations in the magnitude, even the sign of the calculated heat flux, while the mass flux is less affected.