高速冲击下多胞材料细观结构中波传播规律

目的 获取安全防护结构中细观多胞材料在高速冲击下的波传播规律.方法 采用基于3D-Voronoi细观多胞结构数值仿真和基于最小二乘法的局部应变梯度法,研究细观多胞结构在高速冲击下的冲击波波阵面传播规律.通过细观多胞结构数值仿真提取的位移场数据,结合局部应变梯度法得到界面清晰的冲击波波阵面.结果 冲击端和支撑端分别诱发右...     

Influences and mechanisms of nanofullerene on the horizontal transfer of plasmid-encoded antibiotic resistance genes between E. coli strains

• Sub-inhibitory levels of nC₆₀ promote conjugative transfer of ARGs. • nC₆₀ can induce ROS generation, oxidative stress and SOS response. • nC₆₀ can increase cell membrane permeability and alter gene expression. • Results provide evidence of nC₆₀ promoting antibiotic resistance dissemination. The spread and development of antibiotic resistance globally have led to severe public health problems. It has been shown that some non-antibiotic substances can also promote the diffusion and spread of antibiotic resistance genes (ARGs). Nanofullerene (nC₆₀) is a type of nanomaterial widely used around the world, and some studies have discovered both the biological toxicity and environmental toxicity of nC₆₀. In this study, cellular and molecular biology techniques were employed to investigate the influences of nC₆₀ at sub-minimum inhibitory concentrations (sub-MICs) on the conjugation of ARGs between the E. coli strains. Compared with the control group, nC₆₀ significantly increased the conjugation rates of ARGs by 1.32‒10.82 folds within the concentration range of 7.03‒1800 mg/L. This study further explored the mechanism of this phenomenon, finding that sub-MICs of nC₆₀ could induce the production of reactive oxygen species (ROS), trigger SOS-response and oxidative stress, affect the expression of outer membrane proteins (OMPs) genes, increase membrane permeability, and thus promote the occurrence of conjugation. This research enriches our understanding of the environmental toxicity of nC₆₀, raises our risk awareness toward nC₆₀, and may promote the more rational employment of nC₆₀ materials.     

The fate of secondary metabolites in plants growing on Cd-, As-, and Pb-contaminated soils—a comprehensive review

Environmental Science and Pollution Research - The study used scattered literature to summarize the effects of excess Cd, As, and Pb from contaminated soils on plant secondary metabolites/bioactive...     

岷—沱江汞环境背景值研究

本文介绍了用冷原子荧光法测定岷—沱江原水(总汞)、过滤水(溶解性汞)、悬浮物(悬浮态汞)及沉积物中汞含量。方法检测限为0.004μg/l。经选用W检验、Vistelius置信带法和偏度、峰度法联合进行汞含量分布类型检验,综合判断、研究得出岷—沱江水系河水中汞背景值(总量)为0.25μg/l,汞主要以溶解态存在于水体中,沉积物中汞背景值为0.018mg/kg。岷—沱江水系汞背景值无论与国内各水系还是同世界河流水平相比,均处于相同和较低水平。     

固体废物管理技术进展

概述了固体废物管理技术近年来的主要进展,这些进展包括,固体废物从“摇蓝到坟墓”的全过程管理,即从废物产生到收集、运输贮存,再循环,再利用,处理直至最终处理过程所涉及到的：废物最小量化管理技术;废物转移跟踪管理中产生者,运输者,处理处理者,主管当局的职责、主管当局的职责,义务和管理方式;废物经营者向主管当局申请许可证的程序和申请。时,对废物交换制度和废物管理信息系统也作了概要介绍。     

植物硅酸体研究在黄土古气候恢复中的应用

地表植被对环境变化的响应最为敏感 ,沉积物中保存的各种植物残余是古环境研究的良好材料 ,植物硅酸体因其特有的物理化学性质 ,成为古气候信息的绝佳载体。在大量现代植物研究基础上 ,科学家们通过对第三纪以来各种沉积物中硅酸体组合的研究 ,较好地恢复了当时的古植被、古气候及其演化特征 ,在缺乏其它化石依据的黄土地层研究中表现更为突出。由于C3、C4 植物具有明显不同的环境适应性和同位素组成 ,地层中C3、C4 植物硅酸体相对含量和稳定同位素的研究也被成功地应用于古气候恢复中。在现代气候—植被类型和土壤植物硅酸体同位素研究基础上 ,利用数理统计方法 ,建立同位素指标与各种气候因子之间的数学关系 ,将为高分辨率黄土古气候定量研究开辟新的途径。     

沿海农田林网建设关键技术的经济学择优

对江苏沿海地区农田林网的经营类型、造林树种、林带配置进行了技术经济学分析和多目标灰色局势决策择优。结果表明：农田林网经营类型宜选择复合经营的果材兼用型林网。造林树种可选择速生丰产的杨树等用材树种和经济效益高的桃树等果树。林网配置在海堤河岸上选择用材树种，营造基干林带，筑起大网格框架；在道路沟渠上立体配置林果树种，营造主林带和副林带，构建中网格；在脱盐排水沟上添加果树辅助林带，建立小网格，形成多树种多林种合作、大中小网格配套、多道防线联防、多效益多产品产出的复合配置模式。