硫氰酸根在粒状镁铝复合氧化物上的吸附性能

以镁铝水滑石(Mg/Al-LDH)为前驱物制备了粒状镁铝复合氧化物(G-Mg3.3AlO4.8),采用BET、XRD、SEM和FT-IR方法对其结构进行了表征,考察了这种新材料对硫氰酸根(SCN-)的吸附性能.G-Mg3.3AlO4.8的比表面积和平均孔径分别为269.4 m2.g-1和13.25 nm,成型造粒保留了层状结构且无新相生成.Freundlich等温式和准二级动力学方程能很好地描述SCN-在G-Mg3.3AlO4.8上的静态吸附过程,25℃初始浓度为500 mg.L-1时静态吸附量可达165.8 mg.g-1;Yoon-Nelson模型能很好地预测SCN-在G-Mg3.3AlO4.8上的穿透曲线,初始浓度100 mg.L-1、流速5 mL.min-1、床层高度10 cm和pH=6时穿透点吸附量可达50.73 mg.g-1,重复使用4次对SCN-的脱除率均保持在98%以上,是一种可重复利用的高效吸附剂.     

盐雾环境对军用飞机高强螺栓疲劳极限的影响

目的研究军用飞机高强螺栓在模拟海洋大气环境下的疲劳极限变化。方法采用中性盐雾试验对30CrMnSiA高强螺栓进行预腐蚀试验,试验持续时间为360 h,而后再进行96 hCASS试验。腐蚀后对样品进行疲劳试验,并与未腐蚀的样品进行S-N曲线对比分析,并分析其疲劳断口形貌变化。结果在进行盐雾试验后螺栓发生腐蚀,疲劳极限降低28.4%。结论军用飞机用高强螺栓在模拟海洋大气环境下易发生腐蚀,疲劳极限出现明显降低现象,其主要原因为疲劳试验有效面积减少。     

煤巷迎头深部瓦斯赋存规律的实验数据分析

根据近两年来对不同矿区、不同煤层的不同煤巷掘进工作面迎头深部瓦斯赋存量以及突出预测数据的现场及实验室测定结果,得出一个在动态应力场作用下的工作面(掘进、回采)迎头深部瓦斯赋存量随深度变化的一个驼峰曲线,即工作面迎头深部的瓦斯赋存量受采动的影响而在不太深的位置处(如5~10m)会产生一个赋存峰,随着深度的增加瓦斯赋存量并非随之一直增大,其分布特征也与现有认识不尽相同。该测定结果为解释和研究工作面迎头深部的瓦斯运移、应力场分布、突出预测等提供了一个现场数据结论,为煤岩体流变模型的建立提供了相应的参考,也提出针对测定结果的疑问。     

耕地资源流失与经济发展的关系分析

正确协调“吃饭”与“建设”的关系，处理耕地保护与经济发展的矛盾，直接关系到国家的社会稳定和经济持续发展。具有重要的现实意义。文章选择深圳、东莞、上海、无锡、武汉五个城市作为研究区域。搜集上述城市近20年来耕地资源流失量及人均GDP统计数据。分析耕地面积减少与经济发展的关系规律。研究结果表明，耕地资源流失量最初随着人均GDP的增加而增加。当越过某一个阈值后。就开始随着人均GDP的增长而降低。虽然这样的演化规律受政策及其他相关因素的影响有所波动。出现阶段性变化。但基本上仍吻合库兹涅茨曲线的一般特征；耕地资源流失量下降的阈值受城市经济、消费水平的影响，有所差异，上述五城市的阈值在5192元至17751元之间；相应地，二、三产业在城市国内生产总值相应所占的份额基本在86％～97％之间变动。     

微生物燃料电池表观内阻的构成和测量

将微生物燃料电池内部各种阻力用表观内阻统一表征,在建立其等效电路的基础上将表观内阻分为欧姆内阻和非欧姆内阻2部分。通过稳态放电法测量微生物燃料电池表观内阻,在改变外电阻后稳定时间需要60s以上方能保证测定准确性,通过稳态放电法测定一室型微生物燃料电池的表观内阻为289?,当外电阻等于表观内阻时微生物燃料电池对外输出功率达到最大,为241mW/m2;通过电流中断法测量一室型微生物燃料电池的欧姆内阻为99?,测定结果与断电前电流强度无关;当一室型微生物燃料电池对外供电分别处于活化极化区、欧姆极化区和浓差极化区时,非欧姆电阻占总内阻的比例分别为93％、66％和75％,在电池对外供电达到最大时非欧姆占总内阻比例最低。提高微生物燃料电池产电能力需要同时降低电池的欧姆内阻和非欧姆内阻。     

沉积物性质对沉积物微生物燃料电池产电性能的影响

沉积物微生物燃料电池(SMFC)作为一种原位修复手段,既能降解沉积物中有机污染物,又可同时输出电能,具有广阔的应用前景.沉积物的来源和特性对于SMFC的产电及污染物降解性能具有重要影响.本研究采用了不同环境的6种沉积物(VS质量分数为3.1%~12.6%)构建SMFC反应器,研究不同沉积物构建的SMFC的产电性能、有机物去除率以及SMFC液相p H值的变化.实验结果显示,在不外加有机碳源的条件下,只有当沉积物的VS含量较高(12.6%)时,SMFC才可实现稳定产电,最大功率密度为39.6 m W·m-2.而当沉积物的VS含量较低(12%)时,SMFC不能实现自发产电.向6种沉积物中投加乙酸钠作为外加碳源,可明显促进产电.在有外加碳源的条件下,具有较高含盐量的沉积物构建的SMFC产电性能较好,其最大功率密度可达到142.3 m W·m-2.试验还发现,以土壤与厌氧污泥为混合底物的SMFC系统的产电功率密度明显低于纯土壤SMFC系统,显示了厌氧污泥对SMFC产电有抑制作用.     

Use of total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol as an independent biomarker to classify smoking status

Biomarkers of exposure to tobacco smoke are needed. The objective of this study was to develop total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as a biomarker of tobacco smoke independent of serum cotinine. Data from National Health and Nutrition Examination Survey were used to estimate cut-off points on NNAL scale to differentiate participants in various classes of smoking status. A cut-off of 13.4 pg/mL for NNAL differentiated smokers from nonsmokers with a specificity and sensitivity of 92%. NNAL can be used as an independent biomarker of exposure to tobacco smoke with high specificity and sensitivity.     

Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff1

Woltemade, Christopher J., 2010. Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff. Journal of the American Water Resources Association (JAWRA) 46(4): 700-711. DOI: 10.1111/j.1752-1688.2010.00442.x Abstract: Soil disturbances such as excavation and compaction in residential developments affect lawn infiltration rates and stormwater runoff. These effects were investigated via measuring saturated infiltration rates at 108 residential sites and 18 agricultural sites near Shippensburg, south-central Pennsylvania, using a double-ring infiltrometer. Residential sites included four neighborhoods distributed across three soil series classified as hydrologic soil group (HSG) B. Additional parcel data included date of house construction, percentage impervious area, lawn condition, and woody vegetation condition. Measured infiltration rates ranged from 0 to >40 cm/hour. Analysis of variance indicated significantly different mean infiltration rates (p < 0.001) for lots constructed pre-2000 (9.0 cm/hour) and those constructed post-2000 (2.8 cm/hour). Test results were used to determine a “field-tested” HSG for each site, representing disturbed soil conditions. Stormwater runoff was estimated from residential lots for a range of 24-hour design storms using the TR-55 model and several alternative methods of determining curve numbers, including five different representations of soil conditions. Curve numbers and stormwater runoff were substantially higher when based on field-tested HSGs for lots constructed post-2000 compared with lots built pre-2000 and when based on the HSG for undisturbed soils, documenting the magnitude of possible error in stormwater runoff models that neglect soil disturbance.     

Studies on Biodegradation of Nicotine by Arthrobacter sp. Strain HF-2

A nicotine-degrading bacterium, strain HF-2, was isolated from tobacco waste-contaminated soil and identified as a member of Arthrobacter sp. based on morphology, physiological tests, 16S rDNA sequence and phylogenetic characteristics. At thermal denaturation test indicated that the G + C mol% of strain HF-1 was 63.5. The relationship between the growth of the isolate and the nicotine degradation suggested that strain HF-2 could utilize nicotine as sole sources of carbon, nitrogen and energy. Blue pigment was observed during the nicotine degradation by strain HF-2. The isolate grew well at 20 to 33°C, initial pH 6.5 to 8.0 and 0.5 to 2.0 g L^?1 of nicotine concentration in the nicotine inorganic salt media. The maximum growth and nicotine degradation occurred at 30°C, initial pH 7.0 and 0.7 g·L^?1 of nicotine concentration in media under natural incubation condition. Strain HF-2 could degrade 100% of nicotine under the optimized incubation conditions for 43 h. The concentrations of nicotine were monitored by high performance liquid chromatography. This study demonstrates Arthrobacter sp. strain HF-2 had a great ability to degrade nicotine, and it may be available for the application to the bioremediation of environments contaminated by tobacco waste.