从IPCC第四次评估报告看全球气候变化及防灾减灾对策

本文介绍了IPCC第四次评估报告提出的全球气候变化情况,概述了全球气候变化的原因、影响和灾害,提出了相应的防灾减灾应对措施。     

“自由落体”游乐设备直流电机故障分析

创新是大型游乐设施占领市场的核心竞争力,但创新也容易引发各类问题及不确定性,特别是涉及游乐设备可维护性方面,更容易在创新过程中忽视。本文以国外设备供应商生产的“自由落体”游乐设备的故障入手,从研究直流电机故障机理、维修方案以及设计维保建议等几个方面,提出提升直流电机可维护性的举措,主张行业的设计人员不但要聚焦大型游乐设施的趣味性,也要更多关注如何提高大型游乐设施的可靠性、可维护性。     

Turmeric (Curcuma longa L.) tends to reduce the toxic effects of nickel (II) chloride in Allium cepa L. roots

Environmental Science and Pollution Research - The immense protection potential of plant-derived products against heavy metal toxicity has become a considerable field of research. The goal of the...     

水力帷幕防治海水入侵的数值模拟研究

为比较应用于防治海水入侵工程的水力帷幕效果,利用垂向二维非均质流体的对流-弥散模型,运用伽辽金有限元法求解,并用物理实验结果验证其有效性.将模型应用于模拟广西北海市海城区海水入侵过程及水力帷幕防治海水入侵效果,分别计算了超采地下水、抽水、注水和抽-注水情况下咸淡水界面随时间推移过程,并分析咸淡水界面推移与抽、注水流量及抽、注水孔位置之间关系,通过比较得出注水是北海市防治海水入侵较为理想的措施.     

黑河流域产业结构与生态环境耦合关系辨识

产业结构作为人类作用于生态环境的主要环节．与区域资源、环境存在着显著的互动关系。在生态环境脆弱、水资源紧缺的西北干旱区内陆河流域,由于产业发展与流域生态环境及水资源的空间分布不相吻合．导致生态环境严重退化．目前亟需深入研究产业结构与生态环境的耦合关系。本文以黑河流域为典型研究区,通过建立生态环境质量及产业结构效益指标体系,对黑河流域上、中、下游的生态环境质量和产业结构效益作了综合评价,并对二者的耦合关系进行了定量辨识。结果表明：黑河流域产业结构效益自上游向下游在空间上呈倒“U”型,而生态环境质量与环境产业协调度沿河自上游向下游具有基本一致的变化趋势,都依次降低,说明现阶段黑河流域沿河自上游向下游,产业结构对生态环境的依赖性逐渐降低,而破坏性逐渐上升。     

Coexistence of antibiotic resistance genes,fecal bacteria,and potential pathogens in anthropogenically impacted water

Environmental Science and Pollution Research - Microbial indicators are often used to monitor microbial safety of aquatic environments. However, information regarding the correlation between...     

Comparative investigation of toxicity induced by UV-A and UV-C radiation using Allium test

Organisms are increasingly exposed to ultraviolet (UV) rays of sunlight, due to the thinning of the ozone layer and its widespread use in sterilization processes, especially against the SARS-CoV-2 virus. The present study was conducted with the purpose of evaluating the damages of UV-A and UV-C radiations in Allium cepa L. roots. The effects of two different types of UV on some physiological, biochemical, cytogenotoxic, and anatomical parameters were investigated in a multifaceted study. Three groups were formed from Allium bulbs, one of which was the control group. One of the other groups was exposed to 254 nm (UV-C) and the other to 365 nm (UV-A) UV. Growth retardation effect of UV was investigated with respect to germination percentage, total weight gain, and root elongation, while cytogenotoxicity arisen from UV exposure was analyzed using mitotic index (MI) and chromosomal aberration (CA) and micronucleus (MN) frequency. Oxidative stress due to UV application was investigated based on the accumulation of malondialdehyde (MDA) and the total activities of superoxide dismutase (SOD) and catalase (CAT) enzymes. Also, anatomical changes induced by UV-A and UV-C were analyzed in root meristematic cells. UV treatments caused significant reductions in growth-related parameters. Both UV treatments caused a significant increase in MDA levels and induction of SOD and CAT enzymes in root meristematic cells. A decrease in MI and an increase in the frequency of MN and CAs were observed in root tip cells, indicating the cytogenotoxic effect of UV application. Anatomical damages such as epidermis cell damage, cortex cell damage, necrotic zones, giant cell nucleus, and indistinct transmission tissue occurred in cells exposed to UV. All of the physiological, biochemical, cytogenetic, and anatomical damages observed in this study were more severe in cells treated with UV-C compared to UV-A. This study suggested that UV exposure triggered growth inhibition, cytogenotoxicity, oxidative stress, and meristematic cell damages in A. cepa roots depending on the wavelength.

     

Study on mechanical properties and microstructure of recycled fine aggregate concrete modified by Nano-SiO2

Journal of Material Cycles and Waste Management - In this study, the effects of different contents of Nano-SiO2 (NS) on a slump, compressive strength, splitting tensile strength, flexural strength,...