Issues in planetary protection: policy, protocol and implementation

Planetary protection is NASA's term for the practice of protecting solar system bodies from Earth life while protecting Earth from life that may be brought back from other solar system bodies. Spacefaring nations will soon begin retrieving samples from Mars and other solar system bodies. For these samples, planetary protection is in order, and measures are already in place to prevent the forward contamination of Mars and other bodies by Earth microbes and the backward contamination of Earth by possible extraterrestrial life. A major goal of planetary protection controls on forward contamination is to preserve the planetary record of natural processes by preventing human-caused microbial introductions.     

单片机控制汽车里程表显示

介绍一种新型的电子式汽车里程表。该仪表以8031单片机为核心，用LED数码管显示汽车总行驶里程和本次行驶里程。该汽车里程表较机械式汽车里程表具有精度高、误差小、显示清楚醒目、工艺简单等优点。     

EDA技术应用及其仿真实验室建设方案

本文介绍了EDA技术在工程和教学上的应用，并结合建设电子电路仿真实验室的实践，探讨了其主要软、硬件配置，提出了该实验室的建设方案。     

计算机辅助生产成本管理系统的设计与实施

介绍了计算机辅助生产成本管理系统的设计方法 ,以实施计算机辅助生产成本管理为手段 ,降低生产成本 ,达到提高企业竞争力的目的。     

空防对抗仿真的情景想定设计

为使空防对抗仿真更接近实战，对仿真情景想定设计作了改进。将防空区等分成4个扇形区，在确定对突防飞机威胁最大的影响因素的基础上，根据动态规划法得出进袭飞机采用不同航线时防空方不同部署形式的赢得矩阵，并由布朗算法计算该矩阵，得出攻防双方作战方案的选取概率。仿真计算结果表明，该设计方法较合理，避免了仿真的盲目性，对战术仿真有一定的参考价值。     

基坑开挖的试验研究与Plaxis结果的比较讨论

基坑开挖与支护是一个三维空间问题。我国对软土深基坑支护工程的研究已取得一些成果，但对非饱和土地区的深基坑支护工程而言，由于非饱和土中存在负孔隙水压力(基质吸力)，使得其与饱和土在性状上有显著的不同。因而软土深基坑支护工程的许多成功经验不适用于非饱和土。对非饱和土基坑开挖的研究，尚存在许多问题有待解决，其中最主要的问题是挡墙上土压力的分布及变形。采用国际先进的Plaxis程序，将计算结果与室内大型模型试验结果进行对比分析，得出挡墙上土压力的分布及变形规律，以期完善土压力理论。     

机载多目标攻击作战飞行程序研究

主要分析了机载多目标攻击作战飞行程序的设计,从系统的功能逻辑入手,给出多目标攻击功能逻辑流程图,并阐述了采用程序模块化的设计思想和较为灵活的任务调度管理方法.     

Journey to the Moon: Recent results,science, future robotic and human exploration

The upcoming fleet of lunar missions, and the announcement of new lunar exploration initiatives, show an exciting “Journey to the Moon”, covering recent results, science, future robotic and human exploration. We review some of the questions, findings and perspectives given in the papers included in this issue of Advances in Space Research.     

中国航空公司常旅客计划会计的构建

阐述了航空公司常旅客计划所带来的会计问题以及中国航空公司建立常旅客计划会计的紧迫性与可行性;研究与分析了美国、国际航空运输协会以及国际上主要航空公司常旅客计划会计实务;最后着重研究了中国航空公司常旅客计划会计的内容、会计政策的选择,同时提出了适合中国航空公司常旅客计划的会计实务.     

Four-month Moon and Mars crew water utilization study conducted at the Flashline Mars Arctic Research Station,Devon Island,Nunavut

A categorized water usage study was undertaken at the Flashline Mars Arctic Research Station on Devon Island, Nunavut in the High Canadian Arctic. This study was conducted as part of a long duration four-month Mars mission simulation during the summer of 2007. The study determined that the crew of seven averaged 82.07 L/day over the expedition (standard deviation 22.58 L/day). The study also incorporated a Mars Time Study phase which determined that an average of 12.12 L/sol of water was required for each crewmember. Drinking, food preparation, hand/face, oral, dish wash, clothes wash, shower, shaving, cleaning, engineering, science, plant growth and medical water were each individually monitored throughout the detailed study phases. It was determined that implementing the monitoring program itself resulted in an approximate water savings of 1.5 L/day per crewmember. The seven person crew averaged 202 distinct water draws a day (standard deviation 34) with high water use periods focusing around meal times. No statistically significant correlation was established between total water use and EVA or exercise duration. Study results suggest that current crew water utilization estimates for long duration planetary surface stays are more than two times greater than that required.