并行工程在商用飞机研发项目中的益处及其实施方法

使用较少经费和较短时间研发出质量优越的商用飞机是各飞机研发团队的共同目标。阐述了通过使用科学的方法和管理技术,例如并行工程,是商用飞机研发项目达成上述目标的途径之一,介绍了一种具备可操作性的实施并行工程的方法。     

重力仪散热装置的热仿真分析

随着移动平台重力测量精度的不断提高,对重力仪的温度控制提出了更高的要求。为了实现在不同温度环境下的高精度重力测量,本文设计了一种保温散热装置,为重力仪提供第一级温控。利用Fluent软件分别模拟了0℃,22℃和40℃环境温度下此装置内重力仪系统的温度场,并在此基础上,利用高低温箱完成该装置的温度性能实验,验证了此温控方案的可行性。     

基于云贝叶斯网络的运输飞机超轮速风险评估

起飞超轮速严重威胁飞行安全,为了有效评估运输飞机起飞时在不确定性因素影响下的超轮速风险水平,提出一种基于云模型和贝叶斯网络的评估模型。选取抬轮速度、总重、低压转子转速、抬轮率、抬轮时机、升降舵控制量、风的分量、总温8个指标,建立超轮速风险指标体系;运用基于启发式高斯云变换算法和正向高斯云算法的云模型,实现超轮速风险等级...     

用课程群方法加强计算机网络专业课程体系建设

论文从高职高专院校课程体系建设的角度,阐述了课程体系建设的相关背景,基本思想和意义,以及计算机网络专业课程体系建设的特殊性,并提出了用课程群方法进行网络专科课程体系建设的具体实践措施。     

Modeling of the very high velocity impact process with respect to in-situ ionization measurements

This overview deals with very high impact velocities, where complete vaporization of an impacting cosmic dust particle is to be expected upon expansion from the high pressure high temperature state behind the stopping shock (v > 15 km/s). The topics discussed are the mechanics and thermodynamics of compression, adiabatic release, equation of state and nonequilibrium states upon expansion. The case of very high particle porosity (ρ 1 g/cm³) and the case of very small dust masses (m < 10⁻¹⁷ g) are discussed from what one presently knows. The possibility of three body collisions in the expanding gas phase is discussed briefly. The effect of oblique impact is discussed with respect to its relevance to the ionization process. The numbers communicated are up to the highest “experimental” impact velocities (80 km/s, Halley mission). As one goes to lower impact velocities (20 < v < 30 km/s) there is still complete vaporization of the dust particle but ionization out of the bulk of the particle becomes low. Other than thermal processes may become important. Ideas are outlined to understand their physical nature.     

多媒体煤矿安全监测管理系统研究

介绍了现有的煤矿安全监测和安全考勤管理系统的特点及缺陷，探讨了如何将多媒体计算机技术应用于煤矿安全监测管理系统。该系统具有实时监视、紧急救援和事故分析三大特点。     

论高校医院与全科医学

保证高校教职工、大学生的身心健康,是高校医院义不容辞的责任.为此,应探索一条更适合高校实际情况的医疗模式.本文就高校医院应如何为师生员工提供全方位的医疗保健服务进行了初步探讨.     

Survival and alteration of the plasmid-containing microorganism Escherichia coli Z905/pPHL7 introduced into manmade closed aquatic microcosms.

It has been demonstrated that the transgenic microorganism Escherichia coli Z905/pPHL7 (AprLux+) can exist for a long time at an elevated concentration of mineral salts. The microorganism was introduced into microcosms with sterile brackish water (salinity variable from 21 to 22 g l-1) taken from Lake Shira (Khakasia, Russia). The survival of the microorganism was estimated both by measuring the growth of the colonies on solid nutrient media and by the bioluminescence exhibited by the transgenic strain in samples from the microcosms and in the enrichment culture with the added selective factor-ampicillin (50 micrograms/ml). In the enrichment culture, the bioluminescent signal was registered through the 160-day experiment. It has been shown that in the closed microcosms with brackish water the E. coli strain becomes heterogeneous in its ampicillin resistance. The populations of the transgenic strain were mainly represented by isolates able to persist in the medium containing 50 micrograms/ml, but there were also the cells (about 10%) with the threshold of ampicillin resistance not more than 0.05 micrograms/ml. Thus, it was shown that in the microcosms with brackish water and in the absence of the selective factor the transgenic strain survives and retails the recombinant plasmid.     

Periods of quasi-stationary conditions in interplanetary space according to sequences of SEP events

The values of the characteristic decay time of particle fluxes in SEP events vary, as a rule, considerably from event to event. We point out, however, that at times sequences of events having similar decay times were observed over long time intervals (up to one month, and even longer in a few cases). The values of the decay times, however, differed among different sequences. The constancy of the decay phase in each consecutive event of these series suggests that the interplanetary medium was in steady state during the event series, and, because of solar rotation, its uniformity within sectors extended to 90–180° in heliolongitude. The very rarely observed long series (up to 2–3 solar rotations) indicate the steadiness and homogeneity of the plasma and the interplanetary magnetic field (IMF) in the entire inner solar system in the course of this time span. It is pointed out that the neutral current sheet of the IMF does not represent a substantial obstacle for energetic charged particles. Both hemispheres are (above and below the current sheet), at least during the series of solar events, invariant with time, uniform and alike from the viewpoint of the propagation of charged particles. The investigation of such sequences of events can also be useful for forecasting characteristics of SEP events.