藏南马扎拉金-锑矿床:成矿流体性质和成矿物质来源

马扎拉金-锑矿床是藏南巨型金-锑成矿带的重要组成部分,其矿床成因目前仍存在不同认识.通过主要矿石和蚀变围岩的岩相学、矿相学、流体包裹体和稳定同位素分析,探讨了马扎拉金-锑矿床的成矿流体性质、矿质迁移和沉淀机制.结果表明,马扎拉金-锑矿床成矿流体主要来自岩浆水,主成矿期流体为中温(约255℃)、低盐度(2.8%~3.5%NaCleqv)、富CO2流体,成矿压力约150 MPa,流体演化过程中的CO2与水的不混溶是造成矿质沉淀的主要原因,成矿金属主要来源于地层,特别是区域广泛分布的海相火山岩地层.     

西南石漠化区林下土壤养分特征及差异性

文章采用文献检索法收集20世纪90年代以来石漠化区植被修复和土壤研究相关论文,以全国二次土壤普查养分分级标准为基础,探讨林下土壤养分改良情况及土壤化学计量特征。结果表明：（1）中国西南石漠化区林下土壤总有机碳、全氮均值均高于全国二次土壤普查养分一等级,全磷处于二级范围,土壤养分改善效果明显,而全钾含量属于五级低钾区;（2）广西壮族自治区总有机碳和全氮均值为五省（区、市）第一,全磷和全钾位于二等级和四等级,土壤养分含量增加最明显;贵州省总有机碳、全氮高于一等级34%和37%,全磷值在二等级范围,全钾值位于第五等级,贵州省石漠化林下土壤养分改良明显;云南省总有机碳、全磷指标分别高于一等级9%、21%,全氮属于二等级,全钾属于五等级,土壤养分指标有不同程度提高;重庆市总有机碳高于一等级1.75%,全氮和全磷属于二等级,全钾为五省中最高且属于四级,土壤养分指标改良较其他三省慢;湖南省总有机碳指标为二等级,全氮、全磷、全钾值分别属于二等级、五等级、五等级,湖南省需加强石漠化治理的力度;（3）西南石漠化区土壤总有机碳和全氮指标呈正相关,植被生长亦受钾元素限制。其中,广西壮族自治区总有机碳、全氮和全磷存储快,土壤改良效益极其显著;贵州省土壤固碳能力高于全国平均值;云南省石漠化地区土壤钾元素偏低,影响植被生长;重庆市土壤中全钾含量高与总有机碳、全氮、全磷关系不大,氮元素成为限制植物生长的元素;湖南省植被生长需补充磷、钾元素。西南石漠化区植被生长应充分补充钾元素,除此之外,湖南、重庆需加强磷、氮元素的补充;云南、湖南、重庆应借鉴广西壮族自治区生态修复经验,加强石漠化生态治理并发挥效益。     

OLR方法在黑龙江地区中强地震前异常现象的探讨

利用卫星遥感长波辐射(OLR)资料,分析黑龙江省2004年-2008年发生的几次ML 4.0以上中强地震前的OLR资料,发现地震发生前,在震中附近地区有长波辐射增强的特征,可能与强震孕育过程中的热状态有关,识别和提取卫星对地遥感红外波段的热兆信息,可望在中强地震监测预报的层面上有新的突破.     

登陆热带气旋与夏季风相互作用对暴雨的影响

利用《热带气旋年鉴》资料、NCEP/NCAR再分析资料采用动态合成分析方法,研究了登陆热带气旋降水与夏季风急流之间的关系,同时对登陆热带气旋与夏季风急流发生相互作用的典型个例强热带风暴Bilis (0604) 利用数值模拟方法研究了二者之间的相互作用对暴雨的影响。结果表明:登陆后造成大范围强降水的热带气旋往往与低层急流长时间相连,其水汽通量和潜热能显著大于弱降水热带气旋。数值试验结果表明:夏季风低空急流向热带气旋输送水汽对热带气旋结构维持有利,当水汽输送被截断后,热带气旋气旋性结构被破坏,强降水减弱、范围明显缩小;季风急流风速增强时可增加水汽通量输送,使得强降水范围增加、强度增强;在夏季风影响背景下,热带气旋在陆上的移动改变水汽和不稳定能量的分布,而热带气旋本身独特的动力结构使得强降水强度增加。     

A simple method using climatic variables to estimate canopy temperature,sensible and latent heat fluxes in a winter wheat field on the North China Plain

Estimation of evapotranspiration from a crop field is of great importance for detecting crop water status and proper irrigation scheduling. The Penman–Monteith equation is widely viewed as the best method to estimate evapotranspiration but it requires canopy resistance, which is very difficult to determine in practice. This paper presents a simple method simplified from the Penman–Monteith equation for estimating canopy temperature (T_c). The proposed method is a biophysically‐sound extended version of that proposed by Todorovic. The estimated canopy temperature is used to calculate sensible heat flux, and then latent heat flux is calculated as the residual of the surface energy balance. An eddy covariance (EC) system and an infrared thermometer (IRT) were installed in an irrigated winter wheat field on the North China Plain in 2004 and 2005, to measure T_c, and sensible and latent heat fluxes were used to test the modified Todorovic model (MTD). The results indicate that the original Todorovic model (TD) severely underestimates T_c and sensible heat flux, and hence severely overestimates the latent heat flux. However, the MTD model has good capability for estimating T_c, and gives acceptable results for latent heat flux at both half‐hourly and daily scales. The MTD model results also agreed well with the evapotranspiration calculated from the measured T_c. Copyright © 2008 John Wiley & Sons, Ltd.     

太湖、洞庭湖野生青虾肌肉中有机氯农药的气相色谱-质谱法测定

使用气相色谱质谱技术测定了青虾肌肉组织中的8种有机氯农药.包括六氯苯、氯丹、滴滴涕(ΣDDTs)、艾氏剂、狄氏剂、异狄氏剂、七氯和灭蚁灵,对太湖和洞庭湖15个点位29组野士青虾样品的测定结果显示,青虾肌肉组织内残留的有机氯农药主要是六氯苯和滴滴涕,六氯苯含量为nd-13.2μg/kg(湿重),滴滴涕含量为0.790-5.82μg/kg(湿重),洞庭湖青虾肌肉中有机氯农药的含量略高于太湖青虾,两湖青虾肌肉残留有机氯农药在枯水期时的含量多数大于丰水期时的含量.     

Ecosystem Health: Assessment Framework,Spatial Evolution,and Regional Optimization in Southwest China

Regional ecological health,the core of comprehensive ecosystem assessments,is an important foundation for regional exploration,environmental conservation,and sustainable development.The mountainous areas in southwest China are backward in economy,but industrialization and urbanization have been rapid in recent years.This study assessed the ecosystem health of the Sichuan and Yunnan provinces in China using a pressure-state-response(PSR)model.Spatiotemporal patterns of regional ecosystem health were analyzed from 2000 to 2016,including overall characteristics as well as local characteristics.Ecosystem health in most regions was improved over time(Y=0.0058 X–11.0132,R2=0.95,P<0.001),and areas with poorer ecosystem health decreased from half to one-third of the total area.Analysis of the primacy ratio and the variation coefficient confirmed that the gap in health scores between regions has gradually expanded since 2007,but there are more high quality regions overall(Z of Moran’s index<1.96,P>0.05).Overall,the regional ecosystems to the east of the Hu line-an imaginary line dividing east and west China into roughly equivalent parts-were healthier than those to the west.The pressure and state scores of ecosystems were determined by physiographic condition,and the response scores by government policies and social concern.The spatiotemporal patterns of ecosystem health were dominated to a greater extent by natural than anthropogenic factors,which explains why the shift in the patterns aligned with the direction of the Hu line.Dividing regions into key management areas based on natural geographical conditions and socioeconomic development could contribute to the formulation of a reasonable ecological and environmental protection policy,guaranteeing ecosystem services in the long run.     

Structural analysis of a shrimp thymidylate synthase reveals species-specific interactions with dUMP and raltitrexed

Journal of Oceanology and Limnology - Thymidylate synthase (TS) is a key enzyme in the de novo biosynthesis of thymidine monophosphate, serving as a well-known drug target in chemotherapy against...     

基于包络检波和STFT谱分析的探地雷达土壤分层信息识别

土壤分层信息,特别是表土层结构,对土地生产力具有重要影响,是评价土壤质量的一个重要指标。为了快速、准确地获取土壤分层信息,本文利用探地雷达对分层土壤进行了回波信号采集,并分别在时域和频域分析土壤层位置和层厚信息。首先在信号预处理的基础上,借助包络检波方法确定在土壤分层界面在时域上的位置;然后获取电磁波速度,得到土壤分层厚度。考虑到土壤介电常数与电磁波在土壤中传播速度的相关性,采用短时傅里叶变换方法（Short-time Fourier Transform,STFT）获取各土壤层时频域特征值,并利用回归分析建立特征值与介电常数之间的数学关系,实现对各土壤层的介电常数估算,从而计算出电磁波传播速度,进而确定土壤各层厚度。为验证算法的有效性,分别对理想模拟实验环境和农田环境进行了探地雷达实验,结果表明利用包络检波对探地雷达回波信息进行分析,土壤层检出率达到94.5%,借助STFT谱分析进行探地雷达回波速度估计,对于70 cm深度以上土层厚度计算误差大都保持在10%以下,但随着土壤深度的增加,误差变大。总体来说,本方法能有效识别浅层土壤的分层信息,可应用于实际生产中耕层厚度的估测。     

郑州市市区风环境模拟研究

城市风环境是城市微气候研究的一个重要方向,对分析城市热岛效应、空气流通等具有重要意义。本文以郑州市市区为例,使用1971—2018年气象观测数据、2018年建筑分布数据（OSM）和2016年资源三号卫星数据作为数据源,通过运用气象学和GIS技术结合的方法,探究潜在通风廊道,科学量化城市形态对风环境的影响。研究首先借助WindNinja软件,对城市背景风环境进行模拟分析,该计算方法提高了风道定位的精度。然后利用卫星遥感数据制作了数字高程模型（DSM）,结合OSM计算下垫面地表粗糙度。进一步借助ArcGIS软件,利用最小成本路径法（LCP）确定城市潜在通风廊道的位置。结果表明：① 郑州市近年来平均风速缓慢下降,平均每10年下降0.26 m/s;全年主导风向东北风进入城市后受城市形态影响在京广铁路线附近以西逐渐转为东北偏东风,其中在京广快速路以东风速较高,在京广快速路以西风速较低;② 金水区西部、中原区、二七区以及管城区的地表粗糙度较高,通风环境较差;金水区东部和惠济区的地表粗糙度较低,通风环境较好;③根据盛行风向模拟的潜在通风廊道,其共同特点是趋向于低粗糙度的地区。