综放开采顶煤裂隙及其对渗透性研究的意义

在对综放工作面的煤样进行微观研究基础上,首次运用多重分形理论对顶煤裂隙的不均匀性和各向异性进行了定量表征,并将顶煤裂隙不均匀系数运用于渗透系数研究中,计算结果与实测基本吻合,表明运用多重分形方法,可为研究顶煤节理裂隙及其渗透性研究提供一个新的方法。      

空间数据库辅助设计系统的探析与实现

地理信息标准化是很漫长的道路,在实践中常常由于规范性的缺乏而带来很多问题.本文试从提高数据字典的通用性、灵活性和可维护性角度出发,提出了通用基础地理信息数据字典系统的概念,并从规范数据生产过程的角度出发,产生了建立一套全新独立的、由向导生成的数据字典建库方案流程的思路.最后根据以上思路研制开发了空间数据库辅助设计系统.     

Summer Monsoon Rainfall Variability in Central China over the Past 4700 Years and Its Possible Link to Solar Activity

Based on 467 pairs of δ~(18) O and δ~(13) C records and 8 230 Th dates from a stalagmite(BF4) from Xiniu Cave, central China, we present a reconstruction of ~9-yr resolution monsoon rainfall record for the past 4700 years. Our δ~(18) O record shows good coherence with East Asian summer monsoon(EASM) rainfall proxies from adjacent regions during the overlapping intervals, suggesting that δ~(18) O signal in BF4 can be interpreted as a monsoon rainfall proxy. The δ~(13) C variations are related to changes in local processes at the cave site, and regional rainfall and temperature changes.Based on the δ~(18) O record, a series of dry periods can be identified at 4500–4200, 3500–3200, 2800–2500,1900–1600, 1400–1200, 700–500, and 400–200 yr BP, while a series of wet periods can be identified at 4200–3600,2400–2200, 3200–2800, 1100–900, 600–400, and 200–100 yr BP. Power spectrum analysis on our δ~(18) O record reveals significant cycles at ~470 and ~80 yr, coinciding with the typical solar periodic variations. This result suggests that changes in solar activity play a dominant role in driving centennial–decadal monsoon rainfall variation in central China. Due to minor changes in solar irradiance(less than 1.5 W m~(-2)) over the past 4700 years, our record was further compared to the El Ni?o–Southern Oscillation(ENSO) and Pacific Decadal Oscillation(PDO) proxies,confirming that solar forcing on monsoon rainfall changes might be amplified by the ENSO and PDO variations.From 600 to 150 yr BP(the Little Ice Age, LIA), a positive shift of ~2‰ can be revealed in both the δ~(18) O and δ~(13) C records, indicating a cold/dry climatic pattern. By comparing our δ~(18) O and δ~(13) C records with historical documents,we suggest that the climatic deteriorations between 450 and 250 yr BP may have caused serious social unrest at the end of the Ming Dynasty.     

青海化隆基性-超基性岩带铜镍矿成矿条件与找矿潜力

青海化隆基性-超基性岩带是南祁连山一条重要岩带,其内产出若干基性-超基性岩体。通过对化隆基性-超基性岩带的基本地质特征及化隆群结晶基底的综合研究,结合已有研究成果及其相关其他地质信息,发现该基性-超基性岩带中的岩体都不同程度侵位于化隆群中,并具有相似的地质地球化学特征和成矿地质条件。加之带内几处典型的铜镍成矿表现,可见青海化隆基性-超基性岩带具有较好的铜镍成矿条件与找矿潜力。现有的野外工作及找矿实践亦表明了在巨厚红层覆盖下所发育的基性-超基性岩体表现了重要的铜镍矿化显示,同时提示在化隆基性-超基性岩带还有发现新的同类型岩体和铜镍矿床的潜在条件,其资源潜力较好。     

为"天府之国"农业安全把好第一道关--成都经济区生态地球化学调查主要成果

四川自然环境优越，具有发展现代农业的自然资源、生态环境和劳动力优势。但区域性农业生产环境质量，尤其是土壤的质量与安全性状况不清，使全省现代农业发展缺乏科学支撑。成都经济区生态地球化学调查成果表明，生态地球化学调查可以快速、科学、经济、有效地查明区域农业生态环境质量，为四川规划发展现代农业、调整农业结构布局、提高农产品品质提供科学依据，为四川农业和食品安全把好农业生态环境质量关。     

基于探针气体吸附等温线的矿物材料表征技术:Ⅱ.多孔材料的孔隙结构

含纳米孔的天然矿物岩石材料的吸附和催化性能对于表生地球化学过程、材料加工、应用及煤炭开发利用等方面均有着重要意义。本文对比分析了各种纳米孔表征技术,重点介绍了基于吸附等温线的纳米孔研究方法。对三个典型样品等温线数据的模型计算表明,应根据材料中孔的形态(平行板状孔、球形孔和圆柱形孔)选择模型,不同类型孔所对应的计算方法和参数有很大差别。表征材料表面能量均匀的样品可首先考虑采用DFT法;HK法一般只作为定性研究方法,BJH方法受样品本身性质参数的影响较小,且计算简单,可广泛应用于介孔材料的孔径分布的表征。     

青海化隆地区拉水峡铜镍矿床地质、地球化学特征及成因

拉水峡铜镍矿床位于化隆基性—超基性岩带中,岩体几乎全岩发生铜、镍硫化物矿化,且已遭受强烈蚀变,以角闪岩为主。岩浆期主要金属硫化物矿物组合为磁黄铁矿、黄铜矿、镍黄铁矿;热液蚀变期主要有紫硫镍矿、黄铁矿、黄铜矿、针镍矿等;氧化表生期主要为含镍高岭石、含镍绿泥石、孔雀石等。矿石轻稀土元素富集和负Eu异常明显,说明岩浆演化过程中发生了大量斜长石等的分离结晶作用。∑PGE含量平均为2460.46×10-9,（Pd＋Pt）/（Os＋Ir＋Ru）值为0.40~2.00,表明铂族元素与岩浆深部熔离作用密切相关;但Pt/Pd（0.01~2.62）、Pd/Ir（0.91~8.77）说明热液作用对铂族元素具有一定的富集作用。S同位素组成变化范围很小,δ34S平均值为2.24‰,硫化物中的S以地幔S为主。拉水峡矿床的形成经历了岩浆融离贯入、热液叠加改造及表生氧化作用3个阶段。     

Typhoon Vortex Self-Organization in a Baroclinic Environment

Self-organization of typhoon vortex in a baroclinic environment is studied based on eight numerical experiments with the fifth-generation Pennsylvania State University/National Center for Atmospheric Research （PSU/NCAR） Mesoscale Model （MM5）. The results show that, when there are only two 400-km-away mesoscale axisymmetric vortices with a radius of 500 km in the initial field, the two vortices move away from each other during co-rotating till the distance between them greater than a critical distance named co-rotating critical distance. Then, they stop co-rotating. The situation is changed when a small vortex with a radius of 80 kin is introduced in between the two vortices in the initial field, with the two initially separated vortices approaching each other during their co-rotation, and finally self-organizing into a typhoon-like vortex consisting of an inner core and spiral bands. This result supports both Zhou Xiuji＇s view in 1994 and the studies in the barotropic framework concerning the interactions between the same and different scales of vortices. Six other experiments are carried out to study the effects of the initial vortex parameters, including the initial position of the small-scale vortex, the distance and intensity of the initially axisymmetric binary mesoscale vortices. It is found that the distance between the initial axisymmetrie mesoscale vortices is the most important parameter that influences the self-organizing process of the final typhoon-like vortex. This conclusion is similar to that obtained from barotropical model experiments.     

春季中国日最高气温延伸期预报误差分析及订正

数值模式直接输出和经模式后处理得到的预报误差比较,是延伸期逐日要素预报应用基础。针对中国2 583个站点在2020年春季11~30天的日最高温度预报,根据欧洲数值中心的集合预报输出,首先,使用BP-SM（Back-Propagation - Self memory）法和回归法,进行确定性预报订正效果比较;结果表明BP-SM法和回归法都明显降低了预报绝对误差;在11~14天预报中,BP-SM法得到的平均绝对误差为3.3~3.6 ℃,预报准确率超过35%,订正效果更优。其次,基于模式直接输出和BP-SM法获得的概率预报,使用CRPSS (continuous ranked probability skill score)进行了可预报性分析。结果表明,在地形复杂地区,经过订正,预报准确率明显改善。对于延伸期逐日要素预报,合理的模式后处理方法是降低预报误差和提高预报能力的重要环节。