Physical properties and testing of organosilicon esters for their applicability as synthetic lubricants

The constantly growing needs of the operational parameters of machines and engines, especially for aeronautical use, have brought about greater demands on lubricating oils. Various synthetic materials have been used since the Second World War,¹ in increasing quantity, as substitutes for mineral based oil: esters from organic alcohols and mono- or dicarboxyl acids are among the most widespread. Quite a different type of synthetic oil is organosilicon compounds, known as ‘silicones’. This paper reports experimental data for a group of silicon compounds examined in comparison with other materials normally used as bases for synthetic lubricants.     

PHEM T 材料MBE 生长及其应用

我们对PHEMT材料中应变沟道InGaAs层生长条件进行了优化,并采用了LT-GaAs中缺陷扩散的阻挡层.功率PHEMT器件结果为在栅长Lg=1.0μ时,跨导g\-m≥400 ms/mm,BV\-\{DS\}>1 5V,BV\-\{GS\}>10V表明该材料有较好的性能.作为材料的缓冲层,结果表明器件性能优良 ,是国内最好结果.     

Carborane Analogues of Fenoprofen Exhibit Improved Antitumor Activity

Fenoprofen is a widely used nonsteroidal anti-inflammatory drug (NSAID) against rheumatoid arthritis, degenerative joint disease, ankylosing spondylitis and gout. Like other NSAIDs, fenoprofen inhibits the synthesis of prostaglandins by blocking both cyclooxygenase (COX) isoforms, COX-1 the “house-keeping” enzyme and COX-2 the induced isoform from pathological stimuli. Unselective inhibition of both COX isoforms results in many side effects, but off-target effects have also been reported. The steric modifications of the drugs could afford the desired COX-2 selectivity. Furthermore, NSAIDs have shown promising cytotoxic properties. The structural modification of fenoprofen using bulky dicarba-closo-dodecaborane(12) (carborane) clusters and the biological evaluation of the carborane analogues for COX inhibition and antitumor potential showed that the carborane analogues exhibit stronger antitumor potential compared to their respective aryl-based compounds.     

Wasser‐ und Salzhaushalt im Gefüge zementgebundener Baustoffe – Modellierung der auftretenden Mechanismen

Water and Salt in the Pore Structure of Cementitious Building Materials – Modelling the mechanisms Moisture and salt penetration can lead to significant damage in reinforced concrete structures. Thus a realistic calculation of moisture and salt distributions in cementitious building materials is essential to estimate the service life of reinforced concrete structures. The main mechanisms and interactions affecting moisture and salt transport in cementitious building materials were observed and described mathematically with the aim of developing a numerical model. As well as the effect of salt on known moisture transport phenomena, the cause of the self‐sealing effect of concrete against penetrating water was investigated using nuclear magnetic resonance tomography (NMR) and gamma ray absorption. Based on the results, a model was developed which describes the capillary transport of moisture and salt in concrete taking the self‐sealing effect into account.     

Experiments on the Dynamic Behavior of the Chemical Looping Combustion Process

The dynamic operation of thermal power plants becomes more and more important due to more diverse and volatile power sources. Load changes of biomass, bituminous coal and methane were conducted during six experimental runs in a chemical looping combustion pilot plant which combines power generation and CO₂ capture. The resulting step responses of the hydrodynamics and gas concentrations were compared to each other to understand the transient behavior of the interconnected fluidized bed system. The influence of the fuel rate and solid circulation on the response time and intensity was assessed.     

Influence of Nozzle Parameters on Spray Pattern and Droplet Characteristics for a Two-Fluid Nozzle

In this study, a two-fluid nozzle, as, e.g., used in fluidized-bed or spray drying applications, is comprehensively characterized regarding the spray pattern and droplet size. To analyze the spray cone, the spray cone angle and the radial mass distribution of the nozzle were measured at varied liquid flow rate, spray air pressure, liquid insert bore diameter, and air cap position. Additionally, droplet size distributions were recorded at different spray settings. In general, the overall spray cone and single droplets are significantly influenced by the spray parameters, especially the spray air pressure, as well as the nozzle geometry.     

GaN 基材料生长及其在光电器件领域的应用

GaN具有禁带宽，热导率高，电子饱和漂移速度大和介电常数小等特点，在高度亮发光二极管，短波长激光二极管，高性能紫外探测器和高温，高频，大功率半导体器件等领域有着广泛的应用前景。本文介绍了GaN基半导体材料的制备方法，异质结构以及在光电子和微电子器件领域的应用，并讨论了今后的发展趋势。