气吸式水稻穴播排种器设计与性能试验

为了提升水稻穴播排种器的各项指标,从理论上分析了孔的直径、孔组数、排种盘转速和气吸室真空度等对水稻穴播的影响。在满足水稻农艺要求的基础上,改变了传统的播种方式,并进行了参数优化设计与试验研究。采用计算机视觉试验台完成了单因素试验,对大量试验数据分析表明:气吸室真空度和排种盘转速对实现精密播种、提高排种器工作性能有重要的作用,作业高度的影响可忽略不计。     

不同土壤大气湿度组合下玉米生长及水分光合特性反应

通过对不同土壤大气湿度组合下玉米生长,水分及光合特性的研究,认为土壤水分亏缺对玉米的影响要超过大气干旱,玉米的水分状况及生理活性主要决定土壤的水分条件,短期干旱使气干土干,气湿土干处理净光合率下降的主要原因是非气孔限制,而气干土湿处理前期光合速率下降主要是由于气孔限制,后期则为非气孔限制。短期干旱过程中各处理的干物质仍持续增加。     

桑塔纳汽车空调系统故障的诊断与使用保养

夏天汽车空调的使用频率较高的,空调虽然给人们带来舒适,但出现故障也让人头疼,文章以桑塔纳汽车空调系统为例,对出现的常见故障及正确使用与保养知识进行了分析和介绍,希望能够为大家解决空调系统故障带来方便。     

基于地理信息系统的闽东南柑橘避冻分区及防冻措施研究

通过对福建省66个气象台站的纬度、海拔高度、距海岸线距离等因子与福建省东南部10年1遇极端最低气温之间进行相关和回归分析,研究地理因子对极端最低气温的影响,模拟出极端最低气温在福建省东南部的分布状态,从而确定闽东南柑橘避冻的气候分区,并进一步分析对柑橘防冻的措施;结果表明地理信息系统能很好的模拟闽东南柑橘避冻的气候分区特征,该特征为由东南向西北柑橘气候区划由最适宜种植区逐渐过渡到可能种植区,模拟结果中不存在柑橘不适宜种植区,在闽东南区内,极端最低气温与纬度基本上呈线性相关。     

振动气吸式穴盘播种机的吸种性能研究

为了促进精量播种机的开发与应用,该文对振动气吸式穴盘播种机的吸种性能进行了理论分析。在种子盘近似单频被激振动的情况下,忽略种子空气阻力,使被抛掷的种子“沸腾”起来,以减少种子间的内摩擦力,提高吸种,固种能力。此时把空气流看作等熵流动,从而得出数学模型。试验结果与数学模型基本吻合。结果表明：在一定的真空度下,随着吸嘴直径的增大,吸种能力也随之上升,但吸嘴直径一定要小于种子的直径。吸种质量随吸嘴真空度的增加而提高,真空度较小时,对吸种高度的影响比较明显,真空度较大时,影响较小。真空度有一极限值48 kPa,在此真空度以上不能改善吸种质量;而在一定的真空度下,吸种高度随吸嘴直径变化比较明显均匀。     

蒎烷空气氧化反应的研究

研究了蒎烷的氧化反应,实现了用空气代替纯氧气进行氧化以制备蒎烷氢过氧化物（PHP）的设想。蒎烷的空气氧化反应需要用催化剂;反应时间约在25h左右,比用纯氧氧化延长了3-5h;反应温度一般控制在110℃以内,与纯氧氧化温度类似。在空气氧化蒎烷得到的产物中,PHP含量一般可达45%-50%,与用纯氧氧化的结果相当。氧化产物进行常压催化加氢所得还原产物粗蒎醇用GC分析的结果表明,其蒎醇含量（超过38%）及主要产物组成与用纯氧氧化所得产物基本一致。在回收蒎烷中含较多反式蒎烷。实验结果表明,空气氧化工艺有可能代替纯氧氧化工艺应用于合成PHP的工业生产。     

热风炉受热面壁温控制技术研究

推导了热风炉受热面壁温的计算公式。分析表明,影响壁温的主要因素为烟气温度及放热系数,在受热面前的高温烟气中混入冷烟气或冷空气是降低壁温的有效方法,同一烟温下,浊疑义冷烟气的热风炉热效率较高。混入介质不同受热面中的传热和阻力影响很小。     

Drying Kinetics and Quality Characteristics of Slightly Salted Grass Carp Fillets by Hot Air Drying and Vacuum Microwave Drying

Salted grass carp fillets were dried by hot air drying (HD, at 35 and 45°C) and vacuum microwave drying (VMD, at 1, 4, and 7 W/g) to a final moisture content. Compared with hot air drying, the vacuum microwave drying greatly reduced drying time. The rehydration rate constant of salted grass carp fillets dried by microwave vacuum drying at 7-W/g microwave intensity was significantly higher than that of the hot air drying at 35 and 45°C. Compared with hot air drying, the vacuum microwave dried samples had a higher crude fat content (dry basis). The lightness of the samples dried by vacuum microwave drying was higher, and the yellowness was lower than those dried by hot air drying. The drying methods had no significant effect on the hardness and springiness.     

Evaluation and Analysis of Bacteria Pollution in Dwelling Indoor Air

Tests and study were carried out on indoor air bacteria pollution in dwelling house inChongqing city. Based on the data of measured bacteria concentration of the indoor air,the reasons for indoor air pollution were analyzed. Ith was found that the bacteria seriously polluted the indoor air. The main factors influencing the indoor air bacteria pollution are moisture, natural ventilation and lighting conditions. The construction forms and decoration of the dwelling house are the secondary reasons for indoor air bacteria pollution. Measures and suggestions of preventing the indoor air bacteria pollution and improving the indoor air quality and environmental quality were presented.     

Physiological Experiment for Human Thermal Comfort of Air Flow in Summer

A physiological and psychological experiment was conducted in summer, 2008 to ascertain the effect of air flow on human thermal comfort in hot summer. The statistics analysis shows that air flow makes physiological index and thermal sensation an obvious drop tendency, which is correlated to the air temperature of indoor environment. The lower the air temperature is, the greater the physiological index and the thermal comfort drop. But when the temperature is up to about 34℃, the air flow almost does not make any change to physiological index while the human sensation is still improved. These results indicate that air flow can improve human thermal comfort to some extent, but the improvement has limits. Higher air temperature, strong wind and long time exposure to wind can lead to uncomfortableness.