较低温燃油的使用对缸套磨损的影响

通过对船舶主机故障实例的介绍和分析 ,证实了使用劣质燃油 ,油温过低对船舶主机的损害 。

较低温对渗透剂性能的影响

本文简述了不同标准中对于渗透探伤温度的要求。针对较低温状态下渗透剂的润湿性及运动粘度,进行了试验。结果显示,2~10℃范围内,渗透剂润湿性良好,随着温度降低,渗透剂运动粘度升高。涂-4杯的误差对运动粘度的检测精度有影响。

Variety Test on Low Temperature-resistant Pleurotus ostreatus Strains in Beijing Area

With 7 familiar Pleurotus ostreatus strains in Beijing region as the test materials,the randomized block design method was adopted to analyze the antagonistic effects,mycelial growth rate,yield of mushroom at low temperature season,total biological efficiency and agronomic characteristics of fruit bodies.The results showed that there were antagonistic effects and differences in all the tested items between all the tested strains,of which the strain PL5 had the shortest spawn age,the strain PL3 showed the highest total biological efficiency,and the fructification of the strain PL7 tasted crisp and tender.

Observed trends in diurnal temperature range over Nigeria

The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.

云南镁质氧化镍矿煤基金属化还原过程及优化

以云南元江代表性镁质氧化镍矿为研究对象,在工艺矿物学研究的基础上系统研究了煤作还原剂较低温度下矿的金属化还原过程并对其进行优化。矿物学研究表明硅酸盐为主要组成矿物,占89%;铁氧化物占约10%;前者为主要镍负载矿物,后者为主要铁负载矿物。单因素实验详细考察了温度、时间和煤量对镍、铁富集效果的影响,然而在得到的最优工艺条件下镍、铁回收率仅为14.2%,32.5%。在对氧化镍矿金属化还原热力学分析和过程分析的基础上提出加入促进剂改善镍、铁富集效果。实验研究表明加入促进剂CaF_2可明显改善镍、铁富集效果,具体为优化条件下镍、铁品位分别从2.6%,62.6%升高到6.9%,71.4%;镍、铁回收率分别从14.2%,32.5%升高到96.5%,73.4%;金属化产物中镍铁合金由1μm颗粒状变为20~150μm带状。表明CaF_2可有效破坏矿物结构并降低矿物相界面表面张力,促进镍铁合金相生成/聚合。