废干电池中镍的分布及其含量研究

在实验室条件下,对国产50个品牌80种废干电池中镍的分布及含量进行了研究。结果表明,95%的废干电池含有金属镍,其中碱性废干电池的镍主要分布在外皮(壳)和外底片,碳性废干电池主要分布在金属帽中,钮扣式废干电池分布在正极壳和负极盖。废干电池中镍的质量分数在1%~8.4%之间,平均质量分数为2.4%。废干电池的碳粉中不含镍。     

Effects of Artificial Sand Fixing on Community Characteristics of a Rare Desert Shrub

Eremosparton songoricum (Fabaceae) is a rare, native, clonal small shrub of the deserts of central Asia. Although human activities have greatly fragmented the distribution of E. songoricum, it occurs in areas where artificial sand fixing (AS) has been implemented. We sought to explore whether AS promotes survival and growth of E. songoricum. In the Gurbantunggut Desert of northwestern China in June 2010, we established 10 plots in an area where sand fixing occurred (5–10 years previously) and 11 plots on original sand substrate on which some plants had settled without fixing sand. Sand fixing changed soil properties and biological characteristics in sand‐fixed plots. The soil surface where sand fixing occurred was covered by algal crusts and some lichen, but not bare sand (BS). Soil nutrients; water content of deep soil (30–150 cm); overall plant and herbaceous species richness, diversity, abundance, and cover; above‐ and belowground biomass; and cover, biomass, and height of E. songoricum in the sand‐fixed plots were significantly greater than in plots of BS. However, distribution of E. songoricum individuals in the 2 types of plots did not differ. Our results indicate AS may enhance survival of E. songoricum and increase the overall diversity and stability of the desert plant community. We suggest AS as a way to protect this rare desert plant in situ. Efectos de la Fijación Artificial de Arena sobre las Características de la Comunidad de un Arbusto Desértico Raro     

Effects of sandy desertified land rehabilitation on soil carbon sequestration and aggregation in an arid region in China

The rehabilitation of sandy desertified land in semi-arid and arid regions has a great potential to increase carbon sequestration and improve soil quality. Our objective was to investigate the changes in the soil carbon pool and soil properties of surface soil (0–15 cm) under different types of rehabilitation management. Our study was done in the short-term (7 years) and long-term (32 years) desertification control sites in a marginal oasis of northwest China. The different management treatments were: (1) untreated shifting sand land as control; (2) sand-fixing shrubs with straw checkerboards; (3) poplar (Populus gansuensis) shelter forest; and (4) irrigated cropland after leveling sand dune. The results showed that the rehabilitation of severe sandy desertified land resulted in significant increases in soil organic C (SOC), inorganic C, and total N concentrations, as well as enhanced soil aggregation. Over a 7-year period of revegetation and cultivation, SOC concentration in the recovered shrub land, forest land and irrigated cropland increased by 4.1, 14.6 and 11.9 times compared to the control site (shifting sand land), and increased by 11.2, 17.0 and 23.0 times over the 32-year recovery period. Total N, labile C (KMnO₄–oxidation C), C management index (CMI) and inorganic C (CaCO₃–C) showed a similar increasing trend as SOC. The increased soil C and N was positively related to the accumulation of fine particle fractions. The accumulation of silt and clay, soil C and CaCO₃ enhanced the formation of aggregates, which was beneficial to mitigate wind erosion. The percentage of >0.25 mm dry aggregates increased from 18.0% in the control site to 20.0–87.2% in the recovery sites, and the mean weight diameter (MWD) of water-stable aggregates significantly increased, with a range of 0.09–0.30 mm at the recovery sites. Long-term irrigation and fertilization led to a greater soil C and N accumulation in cropland than in shrub and forest lands. The amount of soil C sequestration reached up to 1.8–9.4 and 7.5–17.3 Mg ha^?1 at the 0–15 cm layer over a 7- and 32-year rehabilitation period compared to the control site, suggesting that desertification control has a great potential for sequestering soil C and improving soil quality in northwest China.     

空气环境质量模糊综合评价方法的改进

针对以往空气环境质量的模糊综合评价方法存在的不足提出了采用综合指数和模糊综合评价方法相结合的方法评价空气环境质量的新方法。     

亚硝酸在冰晶中的存在形态

亚硝酸在冰晶中存在以下平衡:NO2(-→)H+HONO(→)H+H2ONO+(→)H2O+NO+,导致冰晶中的亚硝酸以4种形式的N(Ⅲ):NM2-,HONO,H2ONO2+和NO+存在.实验发现,四种N(Ⅲ)在冰晶中分数与pH值有很大关系:pH>3,主要以NO2-和HONO形式存在;pH<3,主要以HONO,H2ONO+和NO+形式存在.冰晶中的N(Ⅲ)借助以上平衡不断产生HONO并释放到大气中,导致冰晶中N(Ⅲ)不断损失.实验还发现,冰晶中N(Ⅲ)损失率随pH值的升高先升高后下降,随N(Ⅲ)初始浓度升高而升高.紫外光能使冰晶中N(Ⅲ)发生光解,但光解速率很慢,加入·OH猝灭剂也不能提高冰晶中N(Ⅲ)的光解率.     

胶束毛细管电动色谱法研究兰属品种间的亲缘关系

用胶束毛细管电动色谱技术对兰属植物的种质资源多样性及品种间的亲缘关系进行研究．１３个兰属品种的ＣＥ－ＳＤＳ电泳图谱中，共出现３４个蛋白质标记峰，全部为多态性峰，每个样品均有１～２个主峰．邻体聚类结果与形态学分类结果不完全一致．种间的亲缘关系与传统的形态学分类法一致，但建兰种内各品种的聚类不明显     

某铀尾矿库区周围稻田土壤不同组分对U(Ⅵ)的吸附性能分析

通过斯笃克定律提取土壤胶体,连续提取法吸附土壤中的有机质,得到土壤矿质胶体,采用比表面积(BET)法和Zeta电位对原土、土壤胶体和矿质胶体进行了表征分析,考察了溶液pH、接触时间、U(Ⅵ)初始浓度以及温度等因素对3种样品吸附溶液中U(Ⅵ)的影响性能。结果表明:原土、土壤胶体和矿质胶体的比表面积和平均孔径分别为11.5,31.1,28.8 m2/g和18.76,35.55,17.5 nm。在pH为5.5,固液比在1.0 g/L,温度为20 ℃,U(Ⅵ)初始浓度为10.0 mg/L,土壤、土壤胶体反应时间为50 min,矿质胶体反应时间为40 min时,原土、土壤胶体、矿质胶体的对U(Ⅵ)吸附率分别达到76.67%、83.03%、48.87%,吸附容量分别达到8.53,9.24,5.43 mg/g。对比研究结果可以看出,土壤中的胶体对溶液中U(Ⅵ)有着明显的吸附能力,该研究结果对进一步研究含U(Ⅵ)废水的处理及U(Ⅵ)在土壤和地下水中的迁移过程有一定的参考意义。     

国家天然气安全评价指标体系的构建与应用

围绕如何测度并改善天然气安全这一核心议题,引入并修正了APERC能源安全“4A”分析框架,运用层次分析法与德尔斐法,构建了天然气安全评价指标体系,对主要天然气净进口国和净出口国的天然气安全状况进行了量化评估。评估发现：（1）天然气安全四维度（资源可利用性、经济可承受性、贸易可获得性与环境可接受性）的不可或缺性意味着综合表现优异的国家安全水平更高;（2）8个二级指标中,可采储量、个体可承受性等指标的权重更大;（3）天然气净出口国在资源可利用性、经济可承受性和贸易可获得性方面有优势,整体表现优于进口国。就中国而言,可从加快资源开发、完善市场机制、扩大进口渠道和提高资源利用效率四个方面提高天然气安全水平。     

Prevention of surgical site infection under different ventilation systems in operating room environment

• The effectiveness of four different ventilation systems was compared in depth. • Airflow and bacteria-carrying particles concentration were quantitatively analyzed. • Vertical laminar airflow with high airflow rate could not achieve desired effect. • Temperature-controlled airflow ventilation could guarantee air cleanliness. Biological particles in the operating room (OR) air environment can cause surgical site infections (SSIs). Various ventilation systems have been employed in ORs to ensure an ultraclean environment. However, the effect of different ventilation systems on the control of bacteria-carrying particles (BCPs) released from the surgical staff during surgery is unclear. In this study, the performance of four different ventilation systems (vertical laminar airflow ventilation (VLAF), horizontal laminar airflow ventilation (HLAF), differential vertical airflow ventilation (DVAF), and temperature-controlled airflow ventilation (TAF)) used in an OR was evaluated and compared based on the spatial BCP concentration. The airflow field in the OR was solved by the Renormalization Group (RNG) k-e turbulence model, and the BCP phase was calculated by Lagrangian particle tracking (LPT) and the discrete random walk (DRW) model. It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area. This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution, which was greatly affected by obstacles such as surgical lamps and surgical staff.     

Dissipation behavior and risk assessment of butralin in soybean and soil under field conditions

Dissipation behavior, final residue, and risk assessment of butralin in soybean, green soybean, plant, and soil were investigated. Butralin residues were extracted with acetonitrile and then soybean samples were detected with gas chromatography-mass spectrometer (GC-MS) and soil samples were determined with GC with nitrogen phosphorous detector (GC-NPD). The limit of quantification (LOQ) of the method was 0.01 mg/kg for soybean, green soybean, plant, and soil. Average recoveries ranged from 90.4 ~ 98.2% for green soybean, 86.2 ~ 86.6% for soybean, 86.0 ~ 98.8% for plant, and 85.0 ~ 106.8% for soil. The relative standard deviations (RSDs) were 2.0 ~ 7.2% for green soybean, 2.0 ~ 3.0% for soybean, 3.1 ~ 8.1% for plant, and 1.8 ~ 6.6% for soil. Half-lives of butralin in soil samples varied in the range of 11–22 days. At harvest time, final residues of butralin in soybean and green soybean were lower than LOQ. Risk assessment demonstrated that, at recommended dosage and frequency, butralin would not induce significant harm on humans. The study could be used as a quantitative basis for application of butralin on soybean.