清晨起床别忙着开窗换气

早晨起来拉开窗子换换空气,看起来是个很惬意的事情,但是对于在城市中居住的人来说,这种做法并不可取。在一些车流量较大的街道,夜间城市底层大气比白天稳定,不利于污染物的扩散,所以早晨6点左右,污染物浓度依然很高。清晨的时候温度低,气压高,空气中的微小沙尘、不良气体等都被大气压力压在靠近地表的地方,很难向高空散发,经常性地在清晨开窗子换进并不新鲜的空气,对     

水平对置活塞发动机高空热平衡特性研究

目的研究不同海拔大气压力特别是高空条件对水平对置活塞汽油机热平衡性能的影响。方法利用内燃机高空模拟试验台进行不同海拔高度(0~7000 m)下水平对置活塞汽油机的热平衡试验,测得不同海拔下排温、缸体表面温度等特征参数,计算热流量分配特性,并对比分析热流量分配特性随海拔高度的变化规律。结果随海拔升高,汽油机排温和缸体表面温度逐渐下降,且海拔愈高,缸体表面温度下降幅度愈大。汽油机有效功率随海拔升高逐渐下降,余项损失百分比逐渐上升,且在低转速下,变化幅度增大。在6000 m模拟海拔、3000 r/min转速下,汽油机有效热效率不到5%,而余项损失达到了30%以上,此时部分汽油甚至并未燃烧。结论高空环境对水平对置汽油机热平衡性能造成严重影响,成为制约其高海拔性能恢复的关键因素。     

大气压力对细水雾灭火系统泵组流量特性及效率的影响

柱塞泵是泵组式细水雾灭火系统的关键部件,它是细水雾喷头实施喷雾的供水源和压力驱动源.为研究大气压力,特别是高海拔低气压环境对柱塞泵流量特性及效率的影响,通过在合肥及拉萨两地的对比试验,给出了环境压力与柱塞泵流量特性及效率的关系.结果表明,大气压力减小使柱塞泵的流量减小,因此,在高原低气压环境下使用柱塞泵,应采用增加柱塞泵进口压力的措施,以保证泵组式细水雾灭火系统的设计性能;不同大气压力下泵组的效率无明显变化,即大气压力对泵组的效率无明显影响.     

Determination of respiration, gross nitrification and denitrification in soil profile using BaPS system

A facility of BaPS （Barometric Process Separation） was used to determine soil respiration, gross nitrification and denitrification in a winter wheat field with depths of 0-7, 7--14 and 14-21 cm. N2O production was determined by a gas chromatograph. Crop root mass and relevant soil parameters were measured. Results showed that soil respiration and gross nitrification decreased with the increase of soil depth, while denitrification did not change significantly. In comparison with no-plowing plot, soil respiration increased significantly in plowing plot, especially in the surface soil of 0-7 cm, while gross nitrification and denitrification rates were not affected by plowing. Cropping practice in previous season was found to affect soil gross nitrification in the following wheat-growing season. Higher gross nitrification rate occurred in the filed plot with preceding crop of rice compared with that of maize for all the three depths of 0-7, 7-14 and 14-21 cm. A further investigation indicated that the nitrification for all the cases accounted for about 76% of the total nitrogen transformation processes of nitrification and denitrification and the N2O production correlated with nitrification significantly, suggesting that nitrification is a key process of soil N2O production in the wheat field. In addition, the variations of soil respiration and gross nitrification were exponentially dependent on root mass （p〈0.00l）.     

污水生化处理过程中溶解氧的控制方法优劣调研

溶解氧是溶解在水中的分子态氧，它与大气压力、温度等有密切的关系。在污水处理、尤其是生化处理的工艺运行中，溶解氧作为一项至关重要的控制指标，关乎电力资源的消耗、关乎工艺运行能否正常，更关乎处理出水水质。带着这一问题，作者对忻州市污水处理厂生化池的溶解氧的测试方法进行了长时间的探索，得出生化池溶解氧只能直接以在线监测装置或溶解氧便携式测定仪进行测定的结论。     

Modification of FGD gypsum in hydrothermal mixed salt solution

A novel utilization way of the sludge from wet calcium-based flue gas desulfurization （FGD） processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus ,the modification of FGD gypsum was fulfilled.     

深海奇鱼

生命的存在能力,有时是令人难以想象的,甚至是难以置信的。深海鱼类以及深海动物群的存在就是一例。 潜水员曾在千米深的海水中见到过人们熟知的虾、乌贼、章鱼,还有抹香鲸等大型海兽类;在二三千米的水深处发现成群的大嘴琵琶鱼;在8 0 00米以下的水层,发现仅1 8厘米大小的新鱼种。可是你想过没有,这些看似软弱的生命,     

大气压力变化对工作面瓦斯涌出的影响研究

为降低大气压变化造成矿井发生安全事故的可能性，将地面大气压变化数据与某矿工作面瓦斯浓度变化数据进行分析，研究地面大气压的变化规律与传播规律及其对矿井气压的影响，分析大气压变化对工作面瓦斯涌出的作用影响。结果表明：该地区海拔高度每增高1m气压降低大约10 Pa,大气压力发生变化会传递到井下空间，其传递方式与声波相同，且井下压力的变化滞后于大气压力。大气压力的下降速度越快则工作面瓦斯浓度的增加速度也越快，与大气压力下降的具体值关系不大。研究结果可为瓦斯异常涌出预警及相关治理措施的制订提供参考依据。