温度循环条件下某光电舱结雾现象分析

温度循环筛选是提高产品可靠性的重要手段之一,而光电试验舱内温度循环引发的呼吸作用可能是导致光电产品结雾的原因。文章详细分析了某光电舱温度循环时低温结雾的现象,通过理论计算和相关试验,表明器件内部水汽含量过大是此现象出现的主要原因,而密封结构的呼吸作用影响较小。根据以上结果,提出了相关解决措施。     

大型运输机乘员连续供氧呼吸模型及试验分析

基于航空连续供氧系统和呼吸过程，建立了吸入气、气管气各组分计算模型，并依据此模型计算分析了不同乘员供氧标准不同座舱高度所需氧流量。结果表明：所建模型适用于不同乘员类型的连续供氧流量计算，为连续供氧流量标准提供了理论依据。针对大型运输机乘员多的特点，介绍了多乘员连续供氧试验方法、试验原理，并对试验数据进行了分析。试验结果表明：在通气量为15和20 L/min的情况下，12 km及其以下高度各测试点的氧分压均达到100~83.8 mmHg，满足供氧防护生理要求。     

The effects of CO2 on growth and transpiration of radish (Raphanus sativus) in hypobaria

Plants grown on long-term space missions will likely be grown in low pressure environments (i.e., hypobaria). However, in hypobaria the transpiration rates of plants can increase and may result in wilting if the water is not readily replaced. It is possible to reduce transpiration by increasing the partial pressure of CO₂ (pCO₂), but the effects of pCO₂ at high levels (>120 Pa) on the growth and transpiration of plants in hypobaria are not known. Therefore, the effects of pCO₂ on the growth and transpiration of radish (Raphanus sativus var. Cherry Bomb II) in hypobaria were studied. The fresh weight (FW), leaf area, dry weight (DW), CO₂ assimilation rates (C_A), dark respiration rates (DR), and transpiration rates from 26 day-old radish plants that were grown for an additional seven days at different total pressures (33, 66 or 101 kPa) and pCO₂ (40 Pa, 100 Pa and 180 Pa) were measured. In general, the dry weight of plants increased with CO₂ enrichment and with lower total pressure. In limiting pCO₂ (40 Pa) conditions, the transpiration for plants grown at 33 kPa was approximately twice that of controls (101 kPa total pressure with 40 Pa pCO₂). Increasing the pCO₂ from 40 Pa to 180 Pa reduced the transpiration rates for plants grown in hypobaria and in standard atmospheric pressures. However, for plants grown in hypobaria and high pCO₂ (180 Pa) leaf damage was evident. Radish growth can be enhanced and transpiration reduced in hypobaria by enriching the gas phase with CO₂ although at high levels leaf damage may occur.