室内空气中总有机污染物浓度探讨

随机选择安徽南方城,乡８２户家庭居室,以监测空气耗氧量做为一项综合指标反映室内总有机污染状况。研究结果,室内总有机污染浓度水平,农村居室４．８７－５．０５ｍｇ／ｍ＾３,城市居室３．６９－４．１７ｍｇ／ｍ＾３,浓度随着空气污染的程度不同而变化。结果揭示人群活动频繁,吸烟,居室人均容积＜２５ｍ＾３,室温＞５．０℃,风速＜０．０７ｍ／ｓ,ＡＣＨ＜１．０等因素均可使室内总有机污染物浓度增高,加强居室通风及     

任意变截面棒材无模拉伸数学模型的研究

无模拉伸是近年来新开发的一种金属成形工艺。此文在对无模拉伸的发展动态、国内外研究概况等进行综合分析的基础上,分析了任意变截面棒材无模拉伸的变形机制及成形可行性,提出了任意变截面棒材无模拉伸速度或冷热源移动速度的理论计算方法。并提出了几种抛物面棒材无模拉伸的速度模型。经过实验研究证明,此文提出的速度模型较好地表达了任意变截面棒材无模拉伸速度变化规律。     

锥管件无模拉伸数学模型的研究

此文分析了锥形管件无模拉伸的变形机制,提出了锥管形件无模拉伸速度、冷热源移动速度的变化规律,对锥形管壁厚的变化也提出了相应的数学模型,并通过实验研究证明,本文提出的速度模型,较好地表达了锥形管件无模拉伸冷热源速度变化的规律.     

通风换气改善居室空气质量及健康效应的研究

于1988年12月至1989年4月,对417户有儿童居室的通风换气与呼吸道健康状况进行了调查,并以模拟方式探讨改善措施。结果表明,85％居室每小时换气次数(ACH)介于0.5—1.0之间,ACH与儿童呼吸道每100人周(pw)症状率呈负相关关系(P<0.01),ACH<0.5儿童呼吸道症状率3.52/100pw高于其他组;开窗时ACH为关门窗时的4倍,室内空气中CO_2、HCHO、~(222)Rn浓度关门窗为开门时的1—3倍,室内风速<0.05m/s,通风效率E<1,致使污染物逐渐累积,长期接触有害健康,如若以“对流论”组织通风,则可有效地改善空气质量,增进居民健康。     

Biological effects of indoor sunlight in ruraldweling houses

ＢｉｏｌｏｇｉｃａｌｅｆｆｅｃｔｓｏｆｉｎｄｏｏｒｓｕｎｌｉｇｈｔｉｎｒｕｒａｌｄｗｅｌｉｎｇｈｏｕｓｅｓＣｈｅｎＧｕｉｆｕ，ＱｉｕＳｈｉｃｏｎｇ（ＷａｎｎａｎＭｅｄｉｃａｌＣｏｌｌｅｇｅ，Ｗｕｈｕ２４１００１，Ｃｈｉｎａ）Ｂｉｏｌｏｇｉｃａｌｅｆｆ...     

Ni-Co bimetallic catalysts on coconut shell activated carbon prepared using solid-phase method for highly efficient dry reforming of methane

Ni-Co bimetallic catalysts supported on coconut shell activated carbon are synthesized using solid-phase method and investigated for dry reforming of methane, to explore the impact of Ni:Co ratio on the catalyst activity and stability. The catalyst performances are evaluated under the temperature varying from 600 to 900 °C and gas hourly space velocity (GHSV) of 7200 mL/h·g-cat. The characterization results show that metal nanoparticles are produced on the support, and the bimetallic catalyst with an explicit Ni:Co ratio (2:1) is the most beneficial for metal particle dispersion and acquires the minimum particle size of 4.41 nm. The bimetallic catalysts with an explicit Ni:Co ratio of 1:2 and 1:1 exhibit a synergistic effect towards the conversions of CH₄ and CO₂, respectively. The experimental results reveal that the highest CH₄ and CO₂ conversions rise to 94.0% and 97.5% within 12 h at 900 °C on average, respectively, assisted with the two bimetallic catalysts. The intensity of disordered carbon and thermal stability are enhanced with the extension of reforming process, contributing to a long-term catalytic stability. Besides, no obvious carbon deposition is detected, leading to a highly catalytic stability for the bimetallic catalysts.