Boundary Layers in an Ocean Related System

In this article two regularizations of an hyperbolic model system derived from the primitive equations of the ocean (or the atmosphere) are presented. The two regularized systems converge to different limits as the regularization parameter converges to 0. Numerical approximations of these equations and numerical simulations are also presented     

Growth of aluminum nitride thin films prepared by plasma-enhanced atomic layer deposition

Aluminum nitride (AlN) thin films were deposited by atomic layer deposition from aluminum chloride (AlCl₃) and an ammonia/hydrogen plasma. The most important role of the ammonia/hydrogen plasma was to act as a reducing agent to extract Cl from AlCl₃, and to form AlN subsequently. The growth rate was saturated at ∼0.042 nm/cycle, and the thickness was proportional to the number of reaction cycles. Repeating this reaction cycle led to precisely controlled growth. The film properties were analyzed using Auger electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy and time-of-flight elastic recoil detection analysis. The concentration of chlorine and hydrogen impurities was 0.23 and 2.01 at.%, respectively. AlN films showed good anti-oxidation properties when O₂ was annealed at 650 °C for 30 min.     

Effects of Solid-State Reaction Synthesis Processing Parameters on Thermoelectric Properties of MgaSi

The Mg2 Si-matrix thermoelectric material was stnthesized by low temperature solid-state renc-tion.This paper studies the effects of holding time and reaction temperatare on the particle size and the properties of the material, and also studies effects of doping elemental Sb, Te and their doping seqence on the properties of the materiol. The result shows that excessirely high temperature and elongated holding time of solid-state reaction are harmful, there is a range of partiele size to ensure optimum properties and the doping sequence of Sb or Te without influencing the properties.     

电机中几个概念性问题的深入分析

分析了电机中铁心损耗的形成机理及其本质,讨论了直流电机电枢反应的去磁机理,明确了同步发电机准同期并列的含义,从而深刻理解有关基本概念。     

The influence of temperature, pressure, salinity and capillary force on the formation of methane hydrate

We present here a thermodynamic model for predicting multi-phase equilibrium of methane hydrate liquid and vapor phases under conditions of different temperature, pressure, salinity and pore sizes. The model is based on the 1959 van der Waals-Platteeuw model, angle-dependent ab initio inter- molecular potentials, the DMW-92 equation of state and Pitzer theory. Comparison with all available experimental data shows that this model can accurately predict the effects of temperature, pressure, salinity and capillary radius on the formation and dissociation of methane hydrate. Online calculations of the p-T conditions for the formation of methane hydrate at given salinities and pore sizes of sediments are available on: www.geochem-model.org/models.htm.     

Lithium Intercalation Compound Dramatically Influences the Electrochemical Properties of Exfoliated MoS2

MoS₂ and other transition metal dichalcogenides (TMDs) have recently gained a renewed interest due to the interesting electronic, catalytic, and mechanical properties which they possess when down‐sized to single or few layer sheets. Exfoliation of the bulk multilayer structure can be achieved by a preliminary chemical Li intercalation followed by the exfoliation due to the reaction of Li with water. Organolithium compounds are generally adopted for the Li intercalation with n‐butyllithium (n‐Bu‐Li) being the most common. Here, the use of three different organolithium compounds are investigated and compared, i.e., methyllithium (Me‐Li), n‐butyllithium (n‐Bu‐Li) and tert‐butyllithium (t‐Bu‐Li), used for the exfoliation of bulk MoS₂. Scanning transmission electron microscopy (STEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) are adopted for a comprehensive characterization of all materials under investigation. In addition, catalytic properties towards the hydrogen evolution reaction (HER) and capacitive properties are also tested. Different organolithium compounds exhibit different extent of Li intercalation resulting in different degrees of exfoliation. The inherent electrochemical behavior of MoS₂ consisting of significant anodic and cathodic peaks as well as its capacitive behavior and catalytic properties towards hydrogen evolution reaction are strongly connected to the exfoliation compound used. This research significantly contributes to the development of large‐scale synthesis of electrocatalytic MoS₂‐based materials.     

等通道转角挤压自增强等规聚丙烯研究

为了研究等通道转角挤压等规聚丙烯的挤压工艺条件、结构与性能之间的关系,采用90°转角模具及挤压路径A、在熔点以下的160℃制备了不同挤压次数的等规聚丙烯样品,利用广角X射线衍射(WAXD)、差示扫描量热分析(DSC)等手段对其结构进行表征.结果表明,随挤压次数增加,等规聚丙烯分子取向明显增加,材料结晶度提高,试样的力学性能提高十分显著,未挤压试样的抗拉强度为17.13 MPa,经过三次挤压后,抗拉强度提高到59.38 MPa.     

硫酸钾尾液冷冻回收高硫钾比矿物工艺研究

以硫酸钾尾液为原料,研究低温冷冻回收高硫钾比矿物合理的工艺技术路线,探寻适宜的贮存条件,为加工车间夏季高温生产硫酸钾提供优质高硫钾比原料.在低温下进行冷冻试验,根据冷冻结晶矿物产率及其干基组分确定适宜的冷冻温度为-15～5℃,冷冻制得的结晶矿物硫钾比均在3.0～5.1,符合夏季生产硫酸钾所需原料硫钾比>2.5的要求.高...     

Synthesis of C_f/TiAl_3 Composite by Infiltration-In Situ Reaction

Infiltration-in situ reaction synthesis of Cf /TiAl3 composite was investigated. The as-cast material was obtained by titanium particles, carbon fibers and pure aluminum. Titanium particles and carbon fibers were mixed and pressed to form a preform firstly, and then molten pure aluminum was pressed into the preform, subsequently, cooled rapidly. In situ reaction samples were obtained by heating the as-cast material from 600 to 1000 °C for 1 h. The microstructural evolution of in situ reaction samples was an...