株洲清水塘工业区周边土壤微生物群落特征

基于Illumina高通量测序技术分析了株洲清水塘工业区周边土壤的微生物群落特征,研究重金属污染对土壤微生物群落的影响.结果表明,土壤微生物群落的相对丰度和多样性变化趋势一致,均随着重金属污染程度增加而减小;稻田土壤平均相对丰度最高的门是变形菌门(49. 56%),其次为绿弯菌门(13. 07%)和酸杆菌门(8. 77%);较高重金属污染程度下伴随着更高丰度的变形菌门、绿弯菌门与更低丰度的硝化螺旋菌门、酸杆菌门; 4组样品的微生物群落结构相似性较高,OTU重叠度达52. 64%,丰度较高的OTU其微生物群落更趋向于相似;结合Spearman相关性分析,Cr与变形菌门显著负相关,与绿弯菌门显著正相关,Cd、Cu、Pb和Zn与硝化螺旋菌门显著负相关.以上结果表明,重金属污染是影响清水塘工业区周边土壤微生物群落结构的重要因素.     

微囊藻毒素对不同生育期水稻生长的影响

灌溉水中的微囊藻毒素不仅会影响作物生长与产量,还可能沿食物链传递而威胁人类健康。以水稻为试材,研究了不同质量浓度(1μg/L、100μg/L、1 000μg/L、3 000μg/L)微囊藻毒素(MCs)对幼苗期和孕穗期水稻生长与成熟期水稻产量的影响,以及MCs在3个生育期水稻中的积累。结果表明:处理7 d后,1μg/L MCs处理对幼苗期水稻生长有一定促进作用,而对孕穗期水稻生长没有影响,高质量浓度MCs(≥100μg/L)抑制幼苗期和孕穗期水稻的生长;胁迫结束且恢复7 d后,100μg/L处理组孕穗期水稻根长、根表面积恢复能力强于幼苗期,株高、叶面积低于幼苗期,而1 000μg/L和3 000μg/L MCs组水稻各指标不仅未恢复,且劣于胁迫期,水稻产量下降92.4%和95.2%。用酶联免疫法检测发现,胁迫后MCs均在水稻体内富集。对于相同质量浓度MCs处理,幼苗期水稻各器官富集能力最大,孕穗期次之,成熟期最小。3 000μg/L MCs处理组的水稻谷粒中MCs质量比达21.2μg/kg,使人体每天摄入MCs的量可能高于世界卫生组织规定的人体每天吸收MCs的上限值。     

Computational investigation of the effects of knee airbag design on the interaction with occupant lower extremity in frontal and oblique impacts

Objective: The lower extremity of the occupant represents the most frequently injured body region in motor vehicle crashes. Knee airbags (KABs) have been implemented as a potential countermeasure to reduce lower extremity injuries. Despite the increasing prevalence of KABs in vehicles, the biomechanical interaction of the human lower extremity with the KAB has not been well characterized. This study uses computational models of the human body and KABs to explore how KAB design may influence the impact response of the occupant's lower extremities.

Methods: The analysis was conducted using a 50th percentile male occupant human body model with deployed KABs in a simplified vehicle interior. The 2 common KAB design types, bottom-deploy KAB (BKAB) and rear-deploy KAB (RKAB), were both included. A state-of-the-art airbag modeling technique, the corpuscular particle method, was adopted to represent the deployment dynamics of the unfolding airbags. Validation of the environment model was performed based on previously reported test results. The kinematic responses of the occupant lower extremities were compared under both KAB designs, 2 seating configurations (in-position and out-of-position), and 3 loading conditions (static, frontal, and oblique impacts). A linear statistical model was used to assess factor significance considering the impact responses of the occupant lower extremities.

Results: The presence of a KAB had a significant influence on the lower extremity kinematics compared to no KAB (P <.05) by providing early restraint and distributing contact force on the legs during airbag deployment. For in-position occupants, the KAB generally tended to decrease tibia loadings. The RKAB led to greater lateral motion of the legs compared to the BKAB, resulting in higher lateral displacement at the knee joint and abduction angle change (51.2 ± 21.7 mm and 15° ± 6.0°) over the dynamic loading conditions. Change in the seating position led to a significant difference in occupant kinematic and kinetic parameters (P <.05). For the out-of-position (forward-seated) occupant, the earlier contact between the lower extremity and the deploying KAB resulted in 28.4° ± 5.8° greater abduction, regardless of crash scenarios. Both KAB types reduced the axial force in the femur relative to no KAB. Overall, the out-of-position occupant sustained a raised axial force and bending moment of the tibia by 0.8 ± 0.2 kN and 21.1 ± 8.7 Nm regardless of restraint use.

Conclusions: The current study provided a preliminary computational examination on KAB designs based on a limited set of configurations in an idealized vehicle interior. Results suggested that the BKAB tended to provide more coverage and less leg abduction compared to the RKAB in oblique impact and/or the selected out-of-position scenario. An out-of-position occupant was associated with larger abduction and lower extremity loads over all occupant configurations. Further investigations are recommended to obtain a full understanding of the KAB performance in a more realistic vehicle environment.     

温度和溶解氧对5083铝合金海水腐蚀性的影响

采用动电位极化和电化学阻抗试验方法,研究了温度和溶解氧对5083铝合金在海水中腐蚀电化学性能的影响。结果表明,随着溶解氧浓度的降低,铝合金自腐蚀电位负移;随着温度的增加,铝合金点蚀电位负移,阴极过程受扩散控制。腐蚀微观形貌分析表明铝合金在高温高氧状态下主要以均匀腐蚀为主,而在低温低氧状态下发生了明显点蚀。     

Pyrolysis behaviors of oil sludge based on TG/FTIR and PY-GC/MS

Pyrolysis is an alternative technology for oil sludge treatment. Thermogravimetric Analysis-Fourier Transform Infrared Spectroscopy and Pyrolysis-Gas Chromatography/Mass Spectrometry were employed to investigate the pyrolysis process and products of oil sludge. The pyrolysis process was divided into five stages: drying and gas desorption, oil volatilization, main pyrolysis, semi-coke charring, and mineral decomposition. The main reaction temperatures ranged from 497.6 K to 753.2 K. The products were mainly composed of pairs of alkane and alkene (carbon number ranges from 1 to 27). The mechanisms consisted of random chain scission followed by end chain scission at high temperatures with volatilization occurring during the whole process. This study is useful not only for the proper design of a pyrolysis system, but also for improving the utilization of liquid oil products.     

可生物降解材料聚羟基脂肪酸酯（PHA）的合成与应用概述

聚羟基脂肪酸酯（polyhydroxyalkanoates,PHA）是很多微生物合成的一种细胞内聚酯,是一种天然的高分子生物材料。PHA具有良好的生物相容性能、生物可降解性和塑料的热加工等性能。文章主要综述了PHA的合成途径与有关应用方面的研究。     

104国道江苏段公路两侧重金属污染现状调查

对104国道江苏段(南京至宜兴段)公路两侧土壤、大气、农作物(水稻)中的主要重金属(铅、镉、铬、铜、锌、镍)含量进行调查与评价,结果显示:国道两侧土壤已受到重金属污染,水稻受重金属铅轻微污染.     

2008年夏季飞云江口浮游植物分布特征及与环境因子的相关性

根据2008年夏季飞云江口海域生态与环境调查数据,分析了飞云江口浮游植物分布特征以及与环境因子的关系.结果表明:2008年夏季共鉴定浮游植物69种,其中硅藻类28属62种,甲藻类3属7种.主要的优势种为中肋骨条藻(Skele-tonema costatum)、尖刺拟菱形藻(Pseudonitzschia pungens)、柔弱伪菱形藻(Pseudonitzschia delicatissima)、环纹娄氏藻(Lauderia annulata)、菱形海线藻(Thalassionema nitzschioides)等.通过CCA梯度分析,影响浮游植物群落结构的主要环境因子为盐度、营养盐、悬浮物、DO、pH,浮游植物不同种群受到的不同的环境因子的影响,甲藻受盐度的影响较大.而硅藻中的角毛藻受到铵盐和亚硝酸盐的影响较大,而中肋骨条藻、尖刺拟菱形藻、菱形海线藻等主要优势硅藻受到环境因子的限制较少.     

污染物在下包气带非饱水条件下迁移转化的研究

一、前言 城市污水施于农田,其中的污染物可能潜入地下水中造成危害,为了控制这种现象的发生,有必要开展污染物在地下包括下包气带的迁移转化规律研究,以供制订有关标准的依据。     

废催化剂浸出规律的静态实验方法

利用静态浸出实验方法对废催化剂中重金属在不同固水比和浸出次数条件下的浸出规律进行了系统研究。实验发现浸出次数大于３次后,重金属的浸出浓度和浸出速率趋于稳定,同时固水比的增加也没有明显改变废催化剂中重金属的浸出。认为在浸取次数大于３次以后,随着表面溶质的溶解,浸出过程主要为内扩散所控制。