伊朗马斯杰德达吉(Masjed Daghi)始新世斑岩成因:来自光谱学与U-Pb年代学和地球化学的证据

伊朗马斯杰德达吉(Masjed Daghi)斑岩型矿床位于阿哈尔—乔勒法(Ahar-Julfa)/阿拉斯巴兰(Arasbaran)成矿带的西北部,目前针对该斑岩矿床的研究相对较少,许多地质问题有待解决.为了补充马斯杰德达吉斑岩型矿床成因的地球化学证据,更好地厘定斑岩形成时间,了解矿床形成过程,对矿区中钻孔采集的石英二长...     

Sea surface temperature retrieval based on simulated microwave polarimetric measurements of a one-dimensional synthetic aperture microwave radiometer

Compared with traditional real aperture microwave radiometers, one-dimensional synthetic aperture microwave radiometers have higher spatial resolution. In this paper, we proposed to retrieve sea surface temperature using a one-dimensional synthetic aperture microwave radiometer that operates at frequencies of 6.9 GHz, 10.65 GHz,18.7 GHz and 23.8 GHz at multiple incidence angles. We used the ERA5 reanalysis data provided by the European Centre for Medium-Range Weather Forecasts and a radiation transmission forward model to calculate the model brightness temperature. The brightness temperature measured by the spaceborne one-dimensional synthetic aperture microwave radiometer was simulated by adding Gaussian noise to the model brightness temperature.Then, a backpropagation(BP) neural network algorithm, a random forest(RF) algorithm and two multiple linear regression algorithms(RE1 and RE2) were developed to retrieve sea surface temperature from the measured brightness temperature within the incidence angle range of 0°–65°. The results show that the retrieval errors of the four algorithms increase with the increasing Gaussian noise. The BP achieves the lowest retrieval errors at all incidence angles. The retrieval error of the RE1 and RE2 decrease first and then increase with the incidence angle and the retrieval error of the RF is contrary to that of RE1 and RE2.     

Impacts of El Ni?o on the somatic condition of Humboldt squid based on the beak morphology

The Humboldt squid Dosidicus gigas has a short life span,and environmental variability plays a significant role in regulating its population dynamics and distribution.An analysis of 1 096 samples of D.gigas collected by the Chinese commercial fishing vessels during 2013,2014,and 2016 off the Peruvian Exclusive Economic Zone,was conducted to evaluate the impacts of El Ni?o events on the somatic condition of D.gigas.This study indicates that the slopes of all beak variables in relation to mantle length(ML)for females were greater than those of males during 2013,2014,and 2016,and slopes of the upper crest length and the lower ro strum length significantly differed between females and males in 2013(P0.05).Variation in the slopes for beak variables among years was studied;no significant difference was observed(ANCOVA,P0.05).The Fulton's condition coefficients(K)of females and males in 2013 and 2014 were significantly greater than tho se in 2016(P0.01).01).The K values of females were greater than tho se of males in 201 3,2014,and 2016,and K values significantly differed between females and males in 201 3.In normal years,the chlorophyll a(Chl a)concentration showed an N-shaped variability from January to December.However,in the El Ni?o period,it tended to weaken the upwelling coupled with warm and low Chl a concentration waters.We suggest that the poor somatic condition of D.gigas during the El Ni?o year was resulted from the low Chl a concentration in the waters,and the abundance of D.gigas would decrease due to the unfavourable environment and the lack of prey items in the El Ni?o year.     

冻融循环作用下砂岩蠕变特性及损伤模型研究

青藏高原高寒地区岩体长期稳定性受冻融作用影响显著,有必要开展冻融岩石的时效性特征研究。为探讨砂岩在冻融循环作用下的蠕变劣化特性,基于不同冻融循环次数后石英砂岩及红砂岩单轴蠕变试验结果,深入分析了冻融循环对砂岩各蠕变阶段的影响特征。研究表明,在非屈服应力条件下,试样在衰减蠕变阶段的蠕变时长随着冻融循环次数的增加而明显减小,对应蠕变量及蠕变速率增大;在屈服应力条件下,试样进入加速蠕变阶段的应力阈值随着冻融循环次数的增加而逐渐降低,对应从稳定蠕变到加速破坏所经历的时间更短,破坏时累计的应变增量更大;在长期荷载作用下,试样的宏观破裂形态随循环次数的增加逐步由单一斜剪切破坏模式向共轭断面拉剪复合型破坏模式演化。根据试验结果,提出了具有冻融与长期受荷劣化特征的非定常性黏弹性系数损伤演化方程,将其引入西原模型构建了考虑冻融损伤的砂岩蠕变本构模型。利用冻融后红砂岩蠕变试验数据对模型进行了参数辨识与比较分析,验证了模型的正确性及适用性。通过对模型参数进行拟合分析,揭示了黏弹性冻融损伤系数随冻融循环次数的变化规律,表明了长期受荷损伤参数具有控制加速蠕变幅度的重要作用。研究结果对于高寒山区岩体长期稳定性评价具有一定意义。     

The Environment Significance of Aerinite — First Discovered in the UBC Cliffs

To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition and structural analyses were carried out by means of X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), electron microprobe analysis (EMPA) and X-ray fluorescence spectra (XRF). Quartz, feldspar, mica, chlorite and aerinite as well as a small amount of amphibole, calcite, clinopyroxene, rutile, perovskite and apatite are recorded in the sediments. It is reported for the first time that the aerinite occurs in a high latitude area and in sediments paragenetic with mica and chlorite. The large span in grain size shows a typical characteristic of fluvioglacial sediments. Geochemistry characteristics (CIA, CIW, PIA, WIP and ICV) verify that there is virtually no chemical weathering. Mineralogy and geochemistry features of the UBC Cliffs sediments indicate that aerinite is accommodate to the high latitude and cold, dry climate. As the sediments show high similarity to those of their provenance, they have great significance in the identification of the forming condition and origin of the aerinite.     

北京市1998～2001年大气气溶胶粒子数浓度分析

通过对北京市1998～2001年气溶胶数浓度的测量,分析了气溶胶粒子谱分布和数浓度变化,揭示了北京市气溶胶数浓度特征及其变化规律,同时还分析了沙尘与北京市气溶胶数浓度的联系.研究表明,北京市气溶胶数浓度自1998年逐年减小,2001年6月开始有所增加,气溶胶数浓度日变化特征同20世纪80年代有较大差异,北京市气溶胶变化与沙尘天气密切相关     

基质镜质体成烃动力学特征研究

干酪根、煤以及显微组分生烃过程中的动力学参数(如活化能分布特征等)是其内部分子结构的宏观反映,据此可以判断有机质内部成键特征,评价生油门限、生油高峰,计算不同温度范围油气生成量等。笔者利用岩石热解仪(Rock-Eval型)对贵州水城含树皮体煤中的主要组成——基质镜质体的成烃动力学特征进行了研究,并与树皮体、丝质体进行比较,结果表明,基质镜质体的平均活化能为200kJ/mol,大于树皮体的平均活化能(177kJ/mol),而小于丝质体的平均活化能(324kJ/mol),由此推断,在相同的热演化条件下,基质镜质体、树皮体、丝质体三者的生烃顺序为树皮体→基质镜质体→丝质体。从基质镜质体生烃活化能分布特征图上可以看出,基质镜质体有4次主要生烃期,其对应的活化能分布范围及产烃率分别为191.25—192.5kJ/mol、12.19%,195—196.25kJ/mol、7.25%,197.5—198.75kJ/mol、39.82%,216.25kJ/mol、18.64%,据此可以认为:基质镜质体主要由4种不同类型键组成。在活化能191.25—198.75kJ/mol范围内,基质镜质体的累计生烃率达60%左右,这说明基质镜质体产烃较集中(在较短的地质剖面或温度范围内形成大量烃类物质),其含量高(煤岩三大组分之一),因此对煤成烃资源有较大的贡献。     

珠江口附近海域波浪场的数值计算与特征分析

本文以WRF模式输出结果作为风场驱动条件,采用SWAN和WAVEWATCHIII相嵌套的方法,对珠江口附近海域进行20年(1991-2010年)的波浪场数值计算。根据计算结果,分析了珠江口海域波高和周期的空间、时间变化特征。结果显示:珠江入海口及近岸Hs较小,外海Hs较大,大部分海域年均Hs在0.4m以上;珠江口附近海域和近海地区年均Te偏小,在2s^3s之间,外海最大可达5s。珠江海域有效波高(Hs)的季节分布呈现出春夏季较小,秋冬季较大的特点。从概率学角度分别统计20年中前5%和10%的Hs及Te,可知:珠江口近海区域Hs,5%在1~2m,大万山群岛处可达Hs,5%2m;在珠江口附近Hs,10%为1.5m,万山海域Hs,10%在2.5m以上;计算海域Te,5%和Te,10%多在4s以上。     

辽东湾近海波流作用下的泥沙浓度特征分析研究

海岸和河口地区是波浪和潮流相互作用最复杂的区域,在潮流和波浪作用下,该区域泥沙运动是当下的研究热点,也是难点。为探究波浪和潮流共同作用下的泥沙悬浊度的分布情况,本文采用辽东湾近海区域实测水文及泥沙悬浊度数据,进行波流作用下的泥沙浓度特征分析研究。分析显示:观测期间,潮流呈现半日潮性质,呈现东北-西南走向,涨潮流流速略大于落潮流流速;观测期间波浪以西南向波浪为主;泥沙浓度与垂向水深呈正比关系,且与流速相关性较好,而与波高、波浪周期相关性较差;利用窦国仁公式对辽东湾近岸泥沙浓度与动力条件关系进行拟合分析,得到α、β分别为0.0045和0.00037,相关系数γ=0.76。     

基于共同犯罪的犯罪人地域关系网络的空间演化及其影响因素——以北京市诈骗案件为例

当前,学界从犯罪人之间的关系模式、关系结构等方面对共同犯罪现象进行了一系列的研究,但缺少对犯罪人地域关系的稳定性分析。论文根据北京市2005、2010、2014年街头诈骗案件数据,利用社会网络原理构建了基于共同犯罪的犯罪人地域关系网络模型,并利用网络分析等方法对参与共同犯罪的犯罪人地域关系网络的结构特征及其变化趋势进行了分析。结果表明：在2005—2014年间,参与北京市共同犯罪的犯罪人籍贯地域的空间分布逐渐集中,并形成了以华北地区为主、多个地域中心并存的格局;犯罪人的地域关系网络小世界效应逐渐增强,并从幂律分布模式向指数分布模式发展;参与共同犯罪的犯罪人群中,北京籍犯罪人的影响力逐渐下降,而河北籍犯罪人的影响力逐渐上升;犯罪人地域关系网络的凝聚子群结构逐渐发生两极分化,出现了少数共同犯罪关系异常密切的犯罪人地域子群结构。针对犯罪人地域关系网络形成及演化的原因,论文从外来人口社会关系重构与亚文化的角度进行了分析和解释,对进一步开展犯罪人的共同犯罪关系模式研究具有一定的启示。