屋顶和建筑表面用陶瓷涂覆彩砂的特性、优点及未来的发展

介绍了沥青瓦用彩砂的性能要求和试验方法,以及美国3M公司在改善彩砂性能方面所取得的研究进展.     

Continuous intrauterine pO2 determination in the fetus during birth

A study about continuous intrauterine pO2-measurement of the human fetus sub partu. It is reported about a continuous intrauterine unbloody pO2-measurement of the human fetus sub partu. There was found a good correlation in different cardiotocographic patterns between labour, fetal heart frequency and pO2-registration.     

Influence of machining processes on rim zone properties and high temperature oxidation behavior of 42CrMo4

The influence of different machining processes, grinding, electrochemical machining, and electro discharge machining on the surface integrity, described by residual stresses, roughness, and chemical composition, is investigated to explain their effect on the high temperature oxidation behavior of martensitic 42CrMo4 steel in an oxygen atmosphere. The results obtained by thermogravimetric in situ experiments reveal that compressive residual stresses and a smaller reactive surface adjusted by grinding lead to an improved oxidation resistance compared with electrochemical machined surfaces. Surface modification by electro discharge machining appears to be most suitable to achieve oxidation resistance due to decelerated initiation of the oxide layer growth compared with the ground surface. The improved oxidation resistance of electro discharge machined and ground surfaces is linked to the modified chemical composition of the rim zone and the rim zone residual stresses, respectively.     

Alkaline hydrothermal zeolites synthesized from high SiO2 and Al2O3 co-disposal fly ash filtrates

A co-disposal reaction was used wherein fly ash (FA) was reacted with acid mine drainage (AMD), to collect filtrates for zeolite synthesis. Raw fly ash as well as fly ash leached with HCl were subjected to the same alkaline hydrothermal zeolite synthesis conditions, as for the co-disposal filtrates, in order to evaluate the zeolitic material obtained. The Si and Al contents of the fly ash (FA) filtrates were used as precursor species for the alkaline hydrothermal conversion of the fly ash filtrates into zeolites. These filtrates were then analysed by XRF spectrometry for quantitative determination of SiO₂ and Al₂O₃. The [SiO₂]/[Al₂O₃] ratio obtained in the filtrates range from 1.4 to 2.5. The [SiO₂]/[Al₂O₃] ratio was used to predict whether the fly ash filtrates could successfully be converted into faujasite zeolitic material by the adopted synthesis procedures. If the [SiO₂]/[Al₂O₃] ratio is higher than 1.5 in the co-disposal filtrates, it favours the formation of faujasite. The zeolite synthesis included an alkaline fusion of the co-disposal filtrates, followed by aging for 8 hours and hydrothermal conversion by crystallisation at 100 °C. Different variables were investigated during the synthesis of zeolite to ascertain their influence on the end product. These variables include adding different amounts of deionised water to the FA-related starting material, using different compositions of FA related starting material and different FA:NaOH ratios in fusing the starting material.     

Model for the electric fields in LDD MOSFETs. I. Field peaks on thesource side

An analytic model for high electric fields on the source side in lightly doped drain (LDD)-type MOSFETs is proposed. The present model explains consistently the dependence of the source field peak on various relevant process and device parameters. It is shown that the source peak plays a role in avalanche and hot-carrier phenomena. The model predictions are compared with the results of extensive 2-D simulations     

Strategies to cope with negative social identity: Predictions by social identity theory and relative deprivation theory.

Predictions by social identity theory (SIT) and relative deprivation theory (RDT) concerning preferences for strategies to cope with a negative in-group status position were tested. The focus of the present research was a comparison of the theories regarding their differential patterns of prediction. For this purpose, a natural sample within a specific historical situation was investigated: East Germans after the German unification. First, the predictive power of SIT and RDT variables was tested separately. In a second step, a possible integration of the theories was addressed. Combining the SIT variables and RDT variables led to an integrated model indicating a differential pattern of prediction for intergroup strategies. The RDT components explained the collective responses, whereas SIT constructs were related to individual strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visualization of electro-physical and chemical machining processes

This paper aims to visualize spatio-temporal phenomena in electro physical and chemical processes in order to understand machining mechanisms and to achieve a technological breakthrough. In situ measurement methods to visualize the time evolution of stress, strain, temperatures, fluid velocities, and species density distributions, together with 2D or 3D images of the workpieces being processed are summarized. Applications of these methods to fundamental studies on electrical discharge machining, electrochemical machining, laser processing and additive manufacturing are introduced. Signal recording and processing technologies and real time monitoring enabling closed-loop feedback control are also discussed.