港湾深槽骤淤的条件探讨

深槽骤淤指深槽底部在特定条件下产生的快速淤积,通常以浮泥形式出现.综合分析杭州湾、三门湾和象山港的地形地貌、水文泥沙及深槽固定剖面风暴前后或大、小潮期间的地形变化得出港湾深槽产生骤淤的基本条件:(1)有丰富的细颗粒物质的供应源;(2)迅速衰减的动力条件;(3)存在明显的负地形.三个条件必须同时得到满足,深槽才能产生骤淤.杭州湾泥沙来源丰富,终年悬沙浓度高,东试挖槽附近受长江冲淡水次级锋面和钱塘江冲淡水锋面影响较大,因此在一个大小潮周期内水动力条件减弱时挖槽处可产生骤淤.三门湾泥沙来源较丰富,正常天气的年份内潮滩处于缓慢淤积状态,而深槽处于冲淤基本平衡状态,但在风暴等灾害性天气下发生强烈的滩、槽泥沙交换,若风暴后处于中小潮汛期则深槽发生骤淤.象山港由于环境隐蔽,水清沙少,沿岸潮滩狭窄,缺少骤淤的物源,即使风暴作用后鹰龙山深槽也没有产生骤淤.     

含水合物粉细砂的三轴试验及模拟

利用水饱和法制备含天然气水合物试样,进行等向压缩试验和不排水三轴试验.采用天然气水合物临界状态(M HCS)模型同时预测排水条件和不排水条件下的三轴试验,并进行变动参数分析.不排水条件下,密实纯砂发生应变硬化,而相近密实度的含水合物试样出现应变软化,峰值偏应力随水合物饱和度和围压增大.通过与排水和不排水三轴试验结果的对...     

微细浸染型金矿深源矿质和流体地球化学示踪研究

在宏观和微观地质特征研究基础上,运用硅同位素动力学分馏原理,结合硅质阴极发光分析,论证了微细浸染型金矿的成矿硅质、矿质和流体主要直接来源于上地幔分异或深部循环的超临界流体,并认为这种深部因素可能对形成大型和超大型矿床发挥了重要作用.这对该类型金矿的成因研究及找矿开辟了新的思路.     

长江口北槽口外悬沙浓度垂线分布的数学模拟

利用垂向一维悬沙运动模型,对长江口北槽口外大、小潮悬沙浓度垂线分布进行模拟,模拟结果同“六点法”实测值拟合较好,表明影响悬沙浓度垂线分布的主要因素为悬沙垂向扩散及絮凝沉降作用。     

Reliability of X-band Dual-polarization Phased Array Radars Through Comparison with an S-band Dual-polarization Doppler Radar

Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs) and an S-band dual-polarization Doppler weather radar(CINRAD/SA-D), the data reliability of DP-PAWR and its ability to detect the fine structures of mesoscale weather systems were assessed. After location matching, the observations of DP-PAWR and CINRAD/SA-D were compared in terms of reflectivity(ZH), radial velocity(V), dif...     

Distribution of clay-sized sediments in streambeds and influence of fine sediment clogging on hyporheic exchange

In this work, the deposition of clay-sized fine particles (d₅₀ = 0.006 mm) and its subsequent influence on the dune-induced hyporheic exchange are investigated. Fine sand (D₅₀ = 0.28 mm), coarse sand (D₅₀ = 1.7 mm), and gravel (D₅₀ = 5.5 mm) grains were used to form homogenous model streambeds; one control - no clay input, and two treatments - increasing clay inputs for each grain type. The results indicate that the clogging profiles of clay-sized sediments may not be predicted accurately using the previously proposed metric based on the relative sizes of infiltrating and substrate sediments. Further, the depositional patterns vary with the initial concentration of clay particles in the surface water. The assessment of clogging profiles in coarse-grained model streambeds also reveals a preferential infiltration of the clay particles in the hyporheic downwelling regions. The results from the dye tracer test suggest that the accumulation of clay particles altered the exchange characteristics in the treatment flumes. For each grain size, the treatment flumes exhibit lower hyporheic flux and higher median residence times compared to their respective control flumes. The dye penetration depths were lower in treatment flumes with fine and coarse sand compared to their respective control flumes. Interestingly, higher penetration depths were observed in treatment flumes with gravel compared to their respective control flume potentially due to the generation of preferential flow paths in the partially clogged gravel beds. The clogging altered the hyporheic fluxes and residence times in the coarse-grained model beds to a greater degree in comparison to the fine sand beds. Overall, our findings indicate that the properties of both fine and substrate sediments influence the clogging patterns in streambeds, and the subsequent influence of fine sediment clogging on hyporheic exchange and associated processes may vary across stream ecosystems.     

一个含有丰富快速精细结构的射电大爆发

本文对１９９０年７月３０日云南天文台四波段（１．４２ＧＨｚ、２．００ＧＨｚ、２．８４ＧＨｚ和４．００ＧＨｚ）太阳射电高时间分辨率同步观测系统［１，２］所观测到的太阳射电大爆发进行了分析，对在１．４２ＧＨｚ、２．００ＧＨｚ、２．８４ＧＨｚ三个波段上观测到的大量尖峰辐射（ｍｓ—ｓｐｉｋｅｓ）作了关于寿命和强度的统计，最后，针对本次爆发中的ｍｓ—ｓｐｉｋｅｓ的特点做了一些讨论。     

基于MICAPS 4的精细化天气预报平台设计及应用

基于气象信息综合分析处理系统第4版(Meteorology Information Comprehensive Analysis Process System4,MICAPS 4)的精细化天气预报平台的设计与应用。从我国精细化气象格点预报业务需求出发,介绍了精细化预报系统的总体组织结构和数据流程,基于MVVM模式的总体架构设计、功能设计以及实现。平台采用高性能的分布式内存对象缓存技术,提高了系统运行效率;采用模型视图分离,将数据逻辑与用户界面剥离,增强其可扩展性,更便于省级本地化应用;开发了要素场协调性处理功能,集成了降水、温度等客观预报算法,并提供丰富的主/客观交互工具。目前,该平台已在业务中应用,为全国精细化预报业务提供了重要支撑。     

Fine and ultrafine gold in placers of northeastern Russia

The main features of the migration and accumulation of fine and ultrafine gold during the evolution of placer-forming processes in northeastern Russia are discussed. The results of loose sediment sampling (over 2000 samples) with a screw separator and strake facilities have been taken into consideration. The approximate grades and potential resources of gold were estimated for various genetic types of placers. The most favorable conditions for the mobilization and accumulation of fine and ultrafine gold in the placers of northeastern Russia prevailed during the Paleogene to Miocene stage of the evolution of orogenic morphostructures, when the residual (illuvial and alluvial) placers were formed. During the Pliocene to Quaternary stage, the tectonic activation caused the reworking of placers by slope and fluvial processes and resulted in the formation of new hillside and alluvial placers. At this stage, the dispersal of fine gold fractions prevailed over accumulation. Under conditions of the periglacial lithogenesis of the Pliocene to Quaternary tectonic activation, the formation of new placers with fine and ultrafine gold derived from primary sources was suppressed due to the low rate of metal release in the process of physical weathering. In terms of the economic importance of placers with fine and ultrafine gold, residual, eluvial, or hillside placers, as well as alluvial stratal placers located in low-order (and partly medium-order) stream valleys, are the most attractive in northeastern Russia. The primary sources of such placers comprise gold-bearing porphry copper, gold-sulfide-quartz, and other hydrothermal deposits with similar placer-forming capability, as well as gold-quartz stockworks. The grade of fine and ultrafine gold in such placers may be as high as a few g/m³. The placers located in the constratal alluvium of graben-type valleys and the bar and floodplain placers in the areas with stockwork-like orebodies containing fine (<0.25 mm) gold are regarded as prospective objects.     

基于3D-GIS的抽水蓄能电厂动态监控与仿真技术研究

文中针对抽水蓄能电厂运营信息化建设的需求与现状,依托高精度三维建模技术、设备动态监控、虚拟仿真等技术,对抽水蓄能电厂进行全方位、多视角的精细测绘与三维建模,同时集成电厂现有系统资源,搭建动态监控与仿真一体化平台,解决目前抽水蓄能电厂信息展现不集中、不直观的缺陷,为电厂三维信息化建设提供新型的解决方案。