大棚土壤剖面EC_(25℃)值变化研究

选取使用多年10个大棚土壤剖面测定。结果表明，90%的大棚土壤全盐量＞1g/kg，出现盐渍化，但其上蔬菜生长良好；EC25℃则80%＜1.0MS/CM。全盐量及各离子含量与EC25℃呈显著和极显著正相关关系。定点定期测定，EC25℃以0~10CM土层变化最大，土层愈深，变化愈小。一年中，4~5月份较高，6月份下降，7~8月份又增高，这和施肥、灌溉及蔬菜生长有关

The study on Moisture Suction in Soil under Shed Protection

主要研究了黑龙江省哈尔滨市一定点大棚内，其土壤水吸力的动态变化.研究表明：0~30CM层次大棚土壤水吸力底层大于表层，表明土壤水分运动方向是从底层流向表层.水吸力在100~400x102PA时，土壤水分处于田间持水量到毛管断裂含水量之间，水分有效性最大.但受人工灌水方式的影响，这种情况只占水分状况的41.8%，其余水分状况或多或少，表明大棚土壤的水分状况不理想.水吸力在4~10月份的生长期内呈周期性变化.This study dealt mainly with the dynamic variation of moisture suction in soil under shed protection in Harbin,Heilongjiang Province.The results showed that the bottom moisture suction in 0￣30cm was more than upper, which indicated that the movement of water was from bottom to upper.When moisture suction was 100￣400cm,the water was between field moisture capacity and capillary disrupting moisture, and the water was the most efficient.But this was affected by irrigation, which was only 41.8% of total water regime, and the rest was more or less, indicating that the water regime in soil under shed protection was not very well

微型内燃机工况下C1–C4烷烃着火延迟数值模拟

燃料着火延迟时间对采用蓄热自着火方式的微型内燃机非常重要。利用Chemkin-Pro软件,分别对甲烷、乙烷、丙烷和正丁烷空气混合气在微型内燃机运行工况下进行着火延迟时间模拟计算,探究初始温度（500 K-1 000 K）、压力（1-10 atm）和当量比（0.6-1.2）对着火延迟时间的影响。同时分析了微型内燃机扫气不尽的尾气残留组分（N2、CO2和H2O）对正丁烷着火延迟时间的影响。结果表明：在四种燃料中,正丁烷的低温着火延迟特性最佳,是一种适合于采用蓄热自着火方式的微型内燃机燃料;初始温度、压力的提高和当量比的增大有利于燃料着火延迟时间的缩短;尾气残留使得燃料着火延迟时间变长,着火延迟特性变差,尾气各组分的热效应和基元反应对燃料着火延迟有着不同的影响机制

Auto-Ignition Delay Time of C1–C4 Alkanes under Micro-Internal Combustion Engine Operative Conditions

The ignition delay time is a crucial parameter in the glow plug ignition of micro-internal combustion engine （MICE）. The effects of important operating parameters, such as the fuel species （methane, ethane, propane and n-butane）, the initial temperature

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel