Earth Observations in China and the World： History and Development in 50 Years

Remote sensing, which came into being at the first International Symposium on Remote Sensing of Environment （ISRSE） 50 years ago, has enabled people to obtain objecive and realistic spatial and temporal information through the application of Earth observation technologies and analyze and understand the macro-level changes of the Earth system from a spaial view. The technology of Earth observaion from space has incomparable advantages in the study of the Earth. This aricle introduces the 50-year development of Earth observaion in the world and the 30-year development of Earth observaion in China and reflects on the building of China＇s Earth observaion system.     

丙酸钙对水螅的急性毒性研究

采用食品防腐剂丙酸钙对水螅进行24H急性毒性实验。结果表明：丙酸钙毒害水螅24h的LC50为2946mg/L。说明流失到自然界水域中的丙酸钙对水螅等淡水生存的动物造成胁迫,并可致动物死亡,并间接或直接地影响水生生态系统及以水螅为食物的下一级消费者。     

MRN complex is an essential effector of DNA damage repair

Genome stability can be threatened by both endogenous and exogenous agents.Organisms have evolved numerous mechanisms to repair DNA damage,including homologous recombination(HR)and non-homologous end joining(NHEJ).Among the factors associated with DNA repair,the MRE11-RAD50-NBS1(MRN)complex(MRE11-RAD50-XRS2 in Saccharomyces cerevisiae)plays important roles not only in DNA damage recognition and signaling but also in subsequent HR or NHEJ repair.Upon detecting DNA damage,the MRN complex activates signaling molecules,such as the protein kinase ataxia-telangiectasia mutated(ATM),to trigger a broad DNA damage response,including cell cycle arrest.The nuclease activity of the MRN complex is responsible for DNA end resection,which guides DNA repair to HR in the presence of sister chromatids.The MRN complex is also involved in NHEJ,and has a species-specific role in hairpin repair.This review focuses on the structure of the MRN complex and its function in DNA damage repair.     

50%IrO_2-50%Ta_2O_5被覆钛阳极涂层的组织结构研究

IrO2-Ta2O5/Ti是优异的电催化活性材料.文章着重研究了广泛应用于析氧领域的钛基被覆50%IrO2-50%Ta2O5二元涂层阳极组织结构变化和涂层形貌.结果表明,涂层经450～600℃烧结,出现IrO2基含Ta固溶体;Ta2O5的晶化温度超过600℃;涂层呈"圆石状"形貌.     

基于TKX-50的PBXs含能材料力学性能计算模拟

在含能材料中添加高分子粘结剂来制备高聚物粘结炸药(PBXs)是改善其力学性能的一种重要手段.含能材料1,1'-二羟基-5,5'-联四唑二羟胺盐(TKX-50)具有高储能、高爆速、低灵敏度和低毒性等特点.将TKX-50分别与HMX和RDX混合得到TKX-50/HMX混合体系和TKX-50/RDX混合体系.该文利用分子动力...     

美丽中国“35目标”和“50愿景”情景模拟

全面建成美丽中国，实现人与自然和谐共生的现代化，是未来30年中国生态文明建设的总目标。总目标包含“35目标”和“50愿景”共2个阶段性目标。文章首先从生态系统要素、结构、过程和功能角度，阐述了对美丽中国目标的理解，继而构建了刻画目标的指标体系，并采用情景模拟方法，模拟了气候变化、人口下降、经济增长趋势下美丽中国“35目标”和“50愿景”。结果表明，至2035年，全国总人口14.4亿人，国内生产总值（GDP）为200万亿元，进入中等发达国家行列。全国森林覆盖率达26%，草原综合植被覆盖度达60%，沙化土地治理率达75%；地表水水质达到Ⅲ类以上，近海海域水质达到Ⅱ类以上；城市空气质量达到国家优良标准。至2050年，全国总人口13.65亿人，GDP为380万亿元，迈入高收入国家行列。森林覆盖率30%，草原综合植被覆盖度65%，沙化土地全部得到有效治理；地表水和近海海域水质均达到Ⅱ类标准；城市空气质量达到发达国家水平。现实状况与目标愿景尚存在明显差距，如期实现美丽中国目标愿景，未来需大力推进减污、降碳、扩绿、增粮和绿色发展。