龙潭水电站不衬砌隧洞设计与放空检查

简介龙潭水电站不衬砌隧洞洞线布置，傍山洞，底板和集石坑等设计概况，其中傍山洞水平覆盖厚度和隧洞底板的稳定引和挪威有关工程经验设计分析，经过２年运用检验和二次放空检查，表明设计是可行的。     

用"缸平移"法提高柴油机模型实时性的方法研究

为了解决柴油机ECU硬件在环仿真时,柴油机模型的精确度和实时性的矛盾,提出了基于充排法的柴油机＂缸平移＂建模方法.在Matlab/Simulink中建立基于充排法的柴油机模型,假设发动机全部气缸以相同方式工作,通过＂缸平移＂法获得＂缸平移＂模型.分别将充排法的发动机模型和＂缸平移＂模型下载到dSPACE Autobox中进行实时仿真,试验表明应用＂缸平移＂方法建立的柴油机模型可以使系统的仿真速度提高三倍.     

航空充氮(氧)车充气回收方法研究

通过理论分析计算和实践验证,对现行航空充氮(氧)车充气导管放空损失进行了深入的分析研究,设计出回气操作法和加装回气瓶的方法,使充氮(氧)车的放空损失下降20%左右,保障能力明显提高。     

Thermodynamic analysis of the emptying process of compressed hydrogen tanks

During the driving of fuel cell vehicles, the fast depressurization of compressed hydrogen tanks plus the high storage pressure and the low thermal conductivity of carbon fiber reinforced plastic (CFRP) can lead to significant cooling of the tank. This can result in a temperature below −40 °C inside the compressed hydrogen tanks and cause safety problems. In this paper, a thermodynamic model that incorporates the nature of external natural convection was developed to describe the emptying process of compressed hydrogen tanks and was validated by experiments. Thermodynamic analyses of the emptying process were performed to study the global heat transfer characteristics and the effects of ambient temperature, defueling rate, defueling pattern, initial and final density of hydrogen gas, liner and CFRP thickness and the crosswind velocity on the final temperature decreases of hydrogen gas, the inner wall and the outer wall.     

Backflow air and pressure analysis in emptying a pipeline containing an entrapped air pocket

ABSTRACT

The prediction of the pressure inside the air pocket in water pipelines has been the topic for a lot of research works. Several aspects in this field have been discussed, such as the filling and the emptying procedures. The emptying process can affect the safety and the efficiency of water systems. Current research presents an analysis of the emptying process using experimental and computational results. The phenomenon is simulated using the two-dimensional computational fluid dynamics (2D CFD) and the one-dimensional mathematical (1D) models. A backflow air analysis is also provided based on CFD simulations. The developed models show good ability in the prediction of the sub-atmospheric pressure and the flow velocity in the system. In most of the cases, the 1D and 2D CFD models show similar performance in the prediction of the pressure and the velocity results. The backflow air development can be accurately explained using the CFD model.     

Effects of oils and pharmaceutical excipients on the bioavailability of ampicillin orally administered,different oily and aqueous suspensions in rabbit

The in vivo bioavailability and in vitro drug-release studies of ampicillin trihydrate in different oily and aqueous suspensions have been investigated. In addition, partition, solubility, and rheological measurements have also been carried out. The in vivo experimental design was based on a 6 × 6 latin square using the rabbit as the test animal. The bioavailability of ampicillin was determined using the plasma levels, which were measured microbiologically. Results of the study showed that oily and sucrose-containing aqueous formulations enhanced the extent of ampicillin absorption, although not statistically significantly, but was close to the borderline of significance. Ampicillin appears to be absorbed at essentially the same rate from both aqueous and oily formulations. The latter showed plasma-level time curves with biphasic absorption and are likely to produce prolonged plasma concentrations of ampicillin because of the effects of enterohepatic recycling. Viscosity appears to play an insignificant role in the results obtained since the bioavailability parameters correlate poorly with the viscosity except C_max. It is suggested that enhancement in the bioavailability of ampicillin is due to the decrease in the gut transit rate brought about by the oil which predominates and masks the other effects of viscosity and osmotic effects of sucrose. The existence of a correlation between the in vitro drug-release rate (t_50%) and viscosity and the lack of a correlation between in vivo and in vitro parameters support the above suggestion and indicate that traditional dissolution rate tests, such as flask-stirrer method, are unsatisfactory as bioavailability indicators when applied to dosage forms that caused marked changes in physiological factors like GER and biliary excretion.     

600MW机组再热器排空管座开裂原因分析与治理

对国华4台600MW亚临界锅炉再热器排空管座(管孔)内壁裂纹和变径处裂纹形成原因的分析表明:管座(管孔)内壁开裂是热疲劳所致;管座变径处开裂是结构应力集中所致。所提出的治理措施正在国华17台600MW亚临界锅炉上逐步实施,再热器排空管座开裂问题已得到有效控制。     

超声波在纳米镍粉制备中的应用

以氨水、Ni(NO3)2·6H2O.为原料,用超声波在微乳液体系(含还原剂)下制备纳米镍。介绍了超声波的空化作用,重点讨论了影响空化的因素对产物粒度的影响。利用X射线衍射(XDR)、透射电子显微镜(TEM)等对样品的成分、晶体结构、粒度及其分布进行了分析。结果表明,用此法得到的纳米镍纯度高,粒径分布窄,平均粒径为35nm,粒径范围在30～40nm。     

Effects of Oils and Pharmaceutical Excipients on the Bioavailability of Ampicillin Orally Administered,Different Oily and Aqueous Suspensions in Rabbit

Abstract

The in vivo bioavailability and in vitro drug-release studies of ampicillin trihydrate in different oily and aqueous suspensions have been investigated. In addition, partition, solubility, and rheological measurements have also been carried out. The in vivo experimental design was based on a 6 × 6 latin square using the rabbit as the test animal. The bioavailability of ampicillin was determined using the plasma levels, which were measured microbiologically. Results of the study showed that oily and sucrose-containing aqueous formulations enhanced the extent of ampicillin absorption, although not statistically significantly, but was close to the borderline of significance. Ampicillin appears to be absorbed at essentially the same rate from both aqueous and oily formulations. The latter showed plasma-level time curves with biphasic absorption and are likely to produce prolonged plasma concentrations of ampicillin because of the effects of enterohepatic recycling. Viscosity appears to play an insignificant role in the results obtained since the bioavailability parameters correlate poorly with the viscosity except C_max. It is suggested that enhancement in the bioavailability of ampicillin is due to the decrease in the gut transit rate brought about by the oil which predominates and masks the other effects of viscosity and osmotic effects of sucrose. The existence of a correlation between the in vitro drug-release rate (t_50%) and viscosity and the lack of a correlation between in vivo and in vitro parameters support the above suggestion and indicate that traditional dissolution rate tests, such as flask-stirrer method, are unsatisfactory as bioavailability indicators when applied to dosage forms that caused marked changes in physiological factors like GER and biliary excretion.     

一体化Orbal氧化沟清淤大修施工实例

无锡市城北污水处理厂三期工程采用一体化奥贝尔(Orbal)氧化沟为主体的A2/O除磷脱氮工艺.介绍了一体化氧化沟在有条件放空的情况下实施清淤大修的施工实例,主要包括前期准备、放空要求、清淤方案、安全措施和实施过程等.