0515台风"卡努"影响浙江的强风分析

本文对0515台风“卡努”登陆浙江后,强度减弱为强热带风暴,对影响浙江沿海海面及沿海地区的外围风速远强于近风暴中心风速进行了分析,分析结果表明:副热带高压的加强、对流层中下层急流的动量下传、高空较强的下沉气流和台风外围气压梯度力迅猛增大的共同作用,是造成本次风暴外围风速远强于近风暴中心风速的重要原因。     

Suppressing non‐Gaussian noises with scaled receiver wavefield for reverse‐time migration: comparison of different approaches

Numerical implementation of the gradient of the cost function in a gradient‐based full‐ waveform inversion (FWI) is essentially a migration operator used in wave equation migration. In FWI, minimizing different data residual norms results in different weighting strategies of data residuals at receiver locations prior to back‐propagation into the medium. In this paper, we propose different scaling methods to the receiver wavefield and compare their performances. Using time‐domain reverse‐time migration (RTM), we show that compared to conventional algorithms, this type of scaling is able to significantly suppress non‐Gaussian noise, i.e., outliers. Our tests also show that scaling by its absolute norm produces better results than other approaches.     

盐酸普鲁卡因诱导下海洋真菌Hypocrea lixii次级代谢化学成分

【目的】通过化学诱导方法从一株海洋真菌Hypocrea lixii中获得多样化的活性小分子化合物。【方法】对菌株在盐酸普鲁卡因的化学诱导作用下进行固体发酵,代谢产物采用硅胶减压柱层析、Sephadex LH-20以及pHPLC等手段分离纯化,对化合物运用NMR、MS等波谱学技术并比对文献进行结构鉴定,采用Ellman比色法及DPPH自由基清除法对化合物进行初步抗乙酰胆碱酯酶(AChE)和抗氧化活性测试。【结果】从海洋真菌Hypocrea lixii在盐酸普鲁卡因诱导下的发酵提取物中分离得到4个异黄酮类化合物,包括6'-O-crotonylgenistin(1)、Genistein(2)、Daidzein(3)和Genistin(4),以及对氨基苯甲酸甲酯(5)、对羟基苯丙酸(6)和胞嘧啶(7),其中化合物1和6为该种中首次报道,化合物5为生物转化来源首次报道,化合物2~4可能源自培养基。在100μmol/L剂量浓度下,化合物1~4对AChE的抑制以及DPPH自由基的清除活性均较弱,化合物5和6显示了相对强的AChE抑制活性,抑制率分别为40%和38%。【结论】盐酸普鲁卡因对该菌次级代谢产生了显著的影响,为深入研究该菌株化学诱导次级代谢产物提供基础。     

Impact of GLONASS pseudorange inter-channel biases on satellite clock corrections

GLONASS carrier phase and pseudorange observations suffer from inter-channel biases (ICBs) because of frequency division multiple access (FDMA). Therefore, we analyze the effect of GLONASS pseudorange inter-channel biases on the GLONASS clock corrections. Different Analysis Centers (AC) eliminate the impact of GLONASS pseudorange ICBs in different ways. This leads to significant differences in the satellite and AC-specific offsets in the GLONASS clock corrections. Satellite and AC-specific offset differences are strongly correlated with frequency. Furthermore, the GLONASS pseudorange ICBs also leads to day-boundary jumps in the GLONASS clock corrections for the same analysis center between adjacent days. This in turn will influence the accuracy of the combined GPS/GLONASS precise point positioning (PPP) at the day-boundary. To solve these problems, a GNSS clock correction combination method based on the Kalman filter is proposed. During the combination, the AC-specific offsets and the satellite and AC-specific offsets can be estimated. The test results show the feasibility and effectiveness of the proposed clock combination method. The combined clock corrections can effectively weaken the influence of clock day-boundary jumps on combined GPS/GLONASS kinematic PPP. Furthermore, these combined clock corrections can improve the accuracy of the combined GPS/GLONASS static PPP single-day solutions when compared to the accuracy of each analysis center alone.     

改性氢氧化镁对地下水中铅镉的稳定化性能研究

为研究OH-缓释剂对铅、镉污染地下水修复的可行性,通过室内实验制备改性氢氧化镁,并对其去除地下水中Pb和Cd的性能进行研究。实验结果表明,重金属的稳定化机理主要为沉淀反应。在去除单一重金属(Pb或Cd)实验中,Pb和Cd的去除率都可达到99%以上,反应符合一级反应动力学,反应速率常数分别为0.173 7 min-1和0.003 7 min-1。改性氢氧化镁在处理Pb和Cd的复合污染时Pb优先于Cd反应,Pb的存在会对Cd的沉淀起到抑制作用。     

辽宁北部早古生代弧－陆碰撞作用的发现及其构造意义

自然资源部中国地质调查局沈阳地质调查中心基础地质室构造研究团队在辽宁北部法库地区地质调查过程中,初步识别出了一次弧－陆碰撞作用.根据地质年代学研究,其主要发生在早古生代.该发现为华北板块北缘东段松辽盆地覆盖区的早古生代的构造演化史研究提供重要依据.     

1979-2010年我国大陆海岸潟湖变迁的多时相遥感分析

潟湖是重要的海岸湿地类型,具有丰富的自然资源和独特的生态功能。近几十年来,我国的海岸潟湖遭到了极大破坏,因此,开展我国海岸潟湖遥感监测与分析具有重要意义。本文根据1979年、1990年、2000年和2010年的4期共102景多时相遥感影像数据,利用遥感和地理信息系统等技术方法对我国大陆海岸潟湖进行了遥感监测,首次调查统计了我国大陆海岸潟湖的名称、数量、分布、岸线长度和面积信息,并对近31年来我国大陆海岸潟湖的变迁状况进行了分析。结果表明,1979年我国大陆海岸潟湖共计251个,近31年,共消失19个潟湖,其中辽宁省消失15个,广东省消失3个,广西壮族自治区消失1个;1979年我国大陆海岸潟湖岸线总长度为2 692.26km,总面积为1 092.805 5km2,至2010年我国大陆海岸潟湖岸线总长度共减少337.80km,潟湖总面积共减少204.103km2;31年间,我国大陆海岸潟湖的岸线长度和潟湖面积总体均处在持续减少的状态,各省(自治区)也基本符合该规律;1979-2010年间,我国大陆海岸潟湖大部分处在老年期,死亡期潟湖消失19个。     

我国业务化海洋观测仪器发展探讨——浅析中美海洋站仪器的差异、趋势及对策

海洋站业务化观测仪器是业务化海洋观测系统的重要实体支撑。将我国海洋站中典型的国产业务化测量仪器与美国同类仪器在性能指标方面进行了对比分析,结合世界前沿海洋仪器发展现状总结了未来主要发展趋势,探讨了我国业务化海洋仪器优先发展的主要方向。结果表明,相比美国,我国国产验潮仪精度低1个数量级,测波仪的波高、周期和波向精度分别平均低0.2 m、0.27 s和5°~10°,国产观测仪器在业务运行可靠性和稳定性方面存在不足。世界海洋观测装备将更加信息化、智能化、专业化和模块化,并通过谱系化发展使其功能日臻完善,可靠性不断提高。在此趋势下,我国业务化海洋观测仪器应优先重点发展高精度传感原件和材料、抗生物污损和防腐蚀技术以及智能电子电路、人工智能和自动化技术等。     

Shortwave cloud radiative forcing on major stratus cloud regions in AMIP-type simulations of CMIP3 and CMIP5 models

Cloud and its radiative effects are major sources of uncertainty that lead to simulation discrepancies in climate models. In this study, shortwave cloud radiative forcing (SWCF) over major stratus regions is evaluated for Atmospheric Models Intercomparison Project (AMIP)-type simulations of models involved in the third and fifth phases of the Coupled Models Intercomparison Project (CMIP3 and CMIP5). Over stratus regions, large deviations in both climatological mean and seasonal cycle of SWCF are found among the models. An ambient field sorted by dynamic (vertical motion) and thermodynamic (inversion strength or stability) regimes is constructed and used to measure the response of SWCF to large-scale controls. In marine boundary layer regions, despite both CMIP3 and CMIP5 models being able to capture well the center and range of occurrence frequency for the ambient field, most of the models fail to simulate the dependence of SWCF on boundary layer inversion and the insensitivity of SWCF to vertical motion. For eastern China, there are large differences even in the simulated ambient fields. Moreover, almost no model can reproduce intense SWCF in rising motion and high stability regimes. It is also found that models with a finer grid resolution have no evident superiority than their lower resolution versions. The uncertainties relating to SWCF in state-of-the-art models may limit their performance in IPCC experiments.