古尔班通古特沙漠腹地土壤水分动态

采用土钻法对古尔班通古特沙漠腹地典型自然沙垄剖面土壤含水量进行长期监测.采取多重比较(LSD)、典型相关分析(MANOVA)、并在国内第一次采用季节交乘趋势等统计方法,对土壤水分与环境因子的关系进行分析,研究结果表明:土壤含水量时间变化规律分为补给期、失水期和冻结滞水期.土壤含水量均值为补给期>冻结滞水期>失水期,变异系数为补给期>冻结滞水期>失水期;土壤含水量空间变化规律表现为:阴阳坡间具有极显著差异(P<0.01,F=0.002 9).垄间分别与坡中、垄顶具有显著性差异(P<0.05).垂直变化分为活跃层、过渡层和稳定层,活跃层与其他土层间均有显著性差异(P<0.05),土壤含水量均值为阴坡>阳坡,垄顶>垄间>坡中.活跃层>过渡层和稳定层;变异系数为阴坡>阳坡,垄间>坡中>垄顶,活跃层>过渡层>稳定层;降雨量和温度是影响研究区土壤水分时间分布变化的重要影响因子,同时也是土壤含水量变化的决定性影响因子,与土壤含水量具有显著相关性(P<0.05,F=0.02).     

Extraction and spatiotemporal evolution analysis of tidal flats in the Bohai Rim during 1984-2019 based on remote sensing

Tidal flats, a precious resource that provides ecological services and land space for coastal zones, are facing threats from human activities and climate change. In this study, a robust decision tree for tidal flat extraction was developed to analyse spatiotemporal variations in the Bohai Rim region during 1984-2019 based on 9539 Landsat TM/OLI surface reflection images and the Google Earth Engine (GEE) cloud platform. The area of tidal flats significantly fluctuated downwards from 3551.22 to 1712.36 km² in the Bohai Rim region during 1984-2019, and 51.31% of tidal flats were distributed near the Yellow River Delta and Liaohe River Delta during 2017-2019. There occurred a drastic spatial transition of tidal flats with coastline migration towards the ocean. Low-stability tidal flats were mainly distributed in reclamation regions, deltas, and bays near the estuary during 1984-2019. The main factors of tidal flat evolution in the Bohai Rim region included the direct impact of land cover changes in reclamation regions, the continuous impact of a weakening sediment supply, and the potential impact of a deteriorating sediment storage capability. The extraction process and maps herein could provide a reference for the sustainable development and conservation of coastal resources.     

太平洋鳕鱼脑中硫苷脂的分离纯化和分析

以太平洋鳕鱼为原料,从鳕鱼脑中分离硫苷脂,确立了提取及纯化的条件,并对硫苷脂的纯度和分子种进行分析。首先,采用氯仿/甲醇(2∶1,v/v)提取总脂。然后,依次采用氯仿/甲醇/水(7∶3∶0.3,v/v/v)洗脱硅胶柱层析,含0.2mol/L乙酸铵的氯仿/甲醇/水(30∶60∶8,v/v/v)洗脱DEAE Sephadex-A25离子交换柱层析,40%甲醇脱盐和100%甲醇洗脱反相C8柱层析,获得硫苷脂纯品。最后,利用500YMC Diol液相色谱柱(3.0mm×250mm,5μm)分离,以正己烷/异丙醇(70∶30,v/v),异丙醇/水/甲酸/氨水(100∶13∶1∶0.14,v/v/v/v)为流动相梯度洗脱,采用负电喷雾电离(ESI)和母离子扫描模式,用液相色谱-串联质谱(LC-MS/MS)法分析了鳕鱼脑硫苷脂的纯度和分子种组成,并比较了其与哺乳动物脑中硫苷脂分子种组成的异同。结果表明,本实验制得的鳕鱼脑硫苷脂纯度为90.74%,与哺乳动物类似,鳕鱼脑硫苷脂的长链碱基以鞘氨醇为主,主要分子种为d18∶1-C24∶1,但脂肪酸的羟基化程度略低,且含少量独特的分子种,如d18∶1-22∶1和d18∶2-25∶2。     

区域GPS网实时计算可降水量的若干问题

目前地基GPS气象学测得的可降水量 (PWV )精度好于 2mm ,但在利用区域GPS网实时计算每个测站上空的PWV时 ,要涉及到很多常规GPS资料处理时所忽略的问题 ,如需考虑数据处理软件和计算方式的选择、站坐标的确定和约束、轨道的使用方法、网外辅助站最佳数量的确定、海潮对实时计算PWV的影响以及实时应用于气象服务时的端部效应等问题。利用上海GPS综合应用网获取的 2 0 0 2年 6、7月份长江三角洲地区入梅前后的数据 ,分析了利用区域性的GPS网实时计算高精度的PWV时要解决的各种问题 ,探讨了其数据处理方案     

细菌源3-羟基脂肪酸作为环境变化代用指标的研究进展

细菌源3-羟基脂肪酸(C10-C18)作为环境变化指示指标具有良好的应用前景,但相关研究还很不系统,在海洋环境中的应用刚刚起步.3-羟基脂肪酸主要用于环境中pH和温度的重建,通过其支链比(异构和反异构3-羟基脂肪酸之和/正构3-羟基脂肪酸之和)与pH的显著正相关关系反演环境中的pH,通过其C15和C17同系物的反异构/...     

大黄鱼倍性检测研究

于2001—2004年对人工诱导大黄鱼的不同发育阶段和不同组织进行倍性检测，胚胎眼泡期采用染色体计数法测定，鱼苗和成鱼阶段用流式细胞法，结果表明，胚胎染色体数目2n=48条为二倍体，3n=72条为三倍体．采用流式细胞法测定鱼苗和成鱼个体时，若受测样品的DNA相对含量值与已知对照组二倍体的比值约为1．5：1，其个体为三倍体；比值约为1：1，则为二倍体，无论用肌肉或尾鳍组织，皆可检测出其个体的倍性。     

库兹涅茨比率的分解及其在我国地区差异分析中的应用

区域差异及其变化是区域经济学和地理学重要的研究课题之一,通过探讨区域差异研究中不同模型之间的关系,结合中国的具体情况指出了基尼系数等指标在描述区域差异方面的局限性。考察了库兹涅茨比率的独特作用,通过对库兹涅茨比率的分解和计算,发现了导致中国区域差异变化的直接原因。改革开放20多年来我国区域差异的变化可以分为四个阶段,不同阶段差异的表现和内在原因不同,取决于低收入地区人口比例和高收入地区经济总量所占比例这两个因素的对比。西部大开发战略已经显现出一定的效果,未来国内区域差异有可能得到一定程度上的缓解。     

Dynamic process analysis of the Niumiangou landslide triggered by the Wenchuan earthquake using the finite difference method and a modified discontinuous deformation analysis

The Niumiangou landslide was the largest landslide triggered by the 2008 Wenchuan earthquake, which was significantly affected by the amplification effect of seismic acceleration. The ringshear experiments indicated that the materials in the source area of the Niumiangou landslide were subjected to friction degradation under a big shear displacement, which may result in rapid movement of the landslide. In order to better understand the landslide movement and study the effect of the friction degradation on movement mechanisms, the dynamic process of Niumiangou landslide was simulated with a new numerical method, which combines the finite difference method(FDM) and the discontinuous deformation analysis(DDA). First, the FDM was used to study the initiation time, amplification effect and velocity of the landslide. Afterwards, these initiation velocities were applied to the blocks in the DDA model by corresponding coordination in the FDM model. A displacementdependent friction model of the sliding surface was incorporated into DDA code to further understand the kinetic behavior of the landslide. The results show that the displacement-dependent friction strongly decreases the friction coefficient of sliding surface under a big displacement, which can obviously promote the run-out and velocity of landslide. The model output well matches the topographic map formed by the landslide. This implies that the proposed model can be applied to the simulation of earthquake-induced landslides with amplification effect, and the friction degradation model is important to clarify the movement mechanism of high-speed and long-distance landslides.     

企业信息技术应用与产业链空间变化——以中国服装纺织企业为例

信息通信技术(ICTs)在经济活动空间重组过程中的作用逐渐被认同,然而不同的空间层级不同的部门其重组过程与特征表现各异,形成的观点和争论多样。企业作为最基本的经济单元在信息化浪潮中发生的变化成为一个重要研究议题。本文以服装纺织企业为研究案例,通过企业访谈获取资料,旨在探讨传统制造业在信息技术下的演变特征,尤其是在信息技术下基于时间成本的生产链空间组织的变化特征。本文主要对服装纺织企业具体的信息技术应用进行了剖析,分析了信息技术下不同发展程度企业生产链空间组织特征及其变化。结果发现服装纺织企业在信息技术下,其设计、生产、配送的周期快速缩减,证明了时间因素在信息技术导致生产链空间组织变革中的重要意义;同时发现信息技术对传统加工制造型纺织服装企业的影响主要表现为生产链某个环节管理功能的加强;而对于产业升级后的企业来说,信息技术对整个生产链空间组织的影响明显。     

Shallow groundwater dynamics in North China Plain

The groundwater level of 39 observation wells including 35 unconfined wells and 4 confined wells from 2004 to 2006 in North China Plain (NCP) was monitored using automatic groundwater monitoring data loggers KADEC-MIZU II of Japan. The automatic groundwater sensors were installed for the corporation project between China and Japan. Combined with the monitoring results from 2004 to 2006 with the major factors affecting the dynamic patterns of groundwater, such as topography and landform, depth of groundwater level, exploitation or discharge extent, rivers and lakes, the dynamic regions of NCP groundwater were gotten. According to the dynamic features of groundwater in NCP, six dynamic patterns of groundwater level were identified, including discharge pattern in the piedmont plain, lateral recharge– runoff–discharge pattern in the piedmont plain, recharge–discharge pattern in the central channel zone, precipitation infiltration–evaporation pattern in the shallow groundwater region of the central plain, lateral recharge–evaporation pattern in the recharge-affected area along the Yellow River and infiltration–discharge–evaporation pattern in the littoral plain. Based on this, the groundwater fluctuation features of various dynamic patterns were interpreted and the influencing factors of different dynamic patterns were compared.