利用高支链类异戊二烯(HBIs)重建极地海冰的研究进展

海冰的准确重建对反演气候和环境变化具有重要意义。近期研究表明,有机指标高支链类异戊二烯(HBIs)具有重建极地海冰状况的潜质,海洋沉积物中具有海冰特异性的单烯HBI(IP_(25))和双烯HBI(IPSO_(25))指标已分别成为研究北极和南极海冰变化的有力工具。本文综述了IP_(25)、IPSO_(25)的提出和验证,分析了影响HBIs生成、迁移和埋藏的诸多因素,总结了为实现精细化区分海冰状况和定量化重建海冰密集度而提出的新指标的发展及应用,并就目前存在的问题和未来研究方向进行了探讨和展望。     

遥感25号无场化相对辐射定标

遥感25号是中国首颗高敏捷亚米级高分辨率光学遥感卫星。常规的偏航相对辐射定标利用卫星或相机偏航90°对地面均匀场进行成像,使得传感器所有探元获取相同的入瞳辐射亮度,实现卫星传感器的相对辐射定标。但拍摄单一地物均匀场并不能实现卫星传感器全动态范围的辐射定标,并降低了该方案的应用效率。本文针对中国遥感25号卫星,提出了不依赖于地面均匀场的无场化偏航辐射定标方法实现遥感25号的高精度高频次相对辐射定标;同时在偏航辐射定标数据处理中提出基于line segment detector(LSD)算法偏航定标数据规定化方法,确保偏航辐射定标图像每一行数据为传感器所有探元对同一地物的成像;采用传感器探元直方图规定化的方法实现遥感25号全动态范围相对辐射定标参数解算。利用遥感25号偏航辐射定标数据进行辐射定标试验并与传统在轨统计辐射定标进行对比,结果表明遥感25号经偏航辐射定标后所有探元平均条纹系数优于0.07%,图像上各种条纹条带噪声以及残余条带噪声得到较好去除,无场化偏航辐射定标方法优于传统在轨统计辐射定标方法。     

On the complex disc–corona interactions in the soft spectral states of soft X-ray transients

Accreting black holes show a complex and diverse behaviour in their soft spectral states. Although these spectra are dominated by a soft, thermal component which almost certainly arises from an accretion disc, there is also a hard X-ray tail indicating that some fraction of the accretion power is instead dissipated in hot, optically thin coronal material. During such states, best observed in the early outburst of soft X-ray transients, the ratio of power dissipated in the hot corona to that in the disc can vary from ∼ 0 (pure disc accretion) to ∼ 1 (equal power in each). Here we present results of spectral analyses of a number of sources, demonstrating the presence of complex features in their energy spectra. Our main findings are: (1) the soft components are not properly described by a thermal emission from accretion discs: they are appreciably broader than can be described by disc blackbody models even including relativistic effects, and (2) the spectral features near     commonly seen in such spectra can be well described by reprocessing of hard X-rays by optically thick, highly ionized, relativistically moving plasma.     

Distinctive C isotopic signature distinguishes a novel sea ice biomarker in Arctic sediments and sediment traps

A C₂₅ highly branched isoprenoid (HBI) monoene hydrocarbon, designated IP₂₅, has been proposed previously to originate from diatoms living in Arctic sea ice, while the presence of IP₂₅ in sediments has been suggested to be a proxy for the occurrence of former Arctic sea ice. Here, we show that the ¹³C isotopic composition of IP₂₅ in sea ice, in sediment trap material collected under sea ice, and in high latitude northern sediments, is distinctive (isotopically ‘heavy’) and distinguishable from that of organic matter of planktonic or terrigenous origin. Mean δ¹³C values for IP₂₅ were − 22.3 ± 0.4‰ (sea ice), − 19.6 ± 1.1‰ (sediment traps) and − 19.3 ± 2.3‰ (sediments). These measurements, therefore, support further the proposed use of IP₂₅ as an Arctic sea ice proxy.     

南羌塘坳陷古油藏原油生物降解作用及意义

对南羌塘坳陷古油藏开展了有机地球化学分析, 从生物标志化合物特征和地质条件探讨古油藏生物降解特征及成藏期次。研究表明, 古油藏储层样品抽提物的正构烷烃分布完整, 但色谱基线发生不同程度抬升, 形成“鼓包”现象, 指示古油藏遭受了一定程度的生物降解作用; 古油藏族组分碳同位素发生“倒转”和普遍检出的25-降藿烷也证实了古油藏经历了中等-严重的生物降解。然而, 古油藏储层样品饱和烃色谱图显示出正构烷烃较为完整, 指示古油藏储层可能经历两期原油充注, 第一次原油遭受了生物降解, 第二期原油保留相对完整的正构烷烃。古油藏储层经历了两次原油充注, 与南羌塘坳陷富有机质页岩经历了两次生排烃的过程是一致。     

塔里木盆地北部塔河油田原油分子地球化学特征及成因类型划分

GC、GC-MS、GC-MS-MS分析表明,塔河17区块各油藏原油饱和烃、芳烃生物标志物组成和稳定碳同位素特征具有同源性,即塔河原油来自相同的烃源灶（或烃源层）。然而,对原油物性特征、成熟度特征、生物降解特征及原油馏分碳同位素组成等的深入研究发现,塔河原油属于早、晚两次充注成藏:早期充注为一般成熟型原油,相当于Ro值0.70%0.80%成熟阶段的生排烃产物,遭受生物降解后具有重、稠油特征,主要分布在4、6、7区下奥陶统储层中;晚期成藏原油相当于Ro值0.80%1.00%的高成熟阶段的生烃产物,表现为正常油、甚至轻质油或凝析油,在塔河油田广泛分布,并可以与早期充注油藏原油的生物降解残留成分进行充分混合,呈现复杂的地球化学特征。      

An upscaling method for one‐phase flow in heterogeneous reservoirs. A weighted output least squares (WOLS) approach

In this paper we study the problem of determining the effective permeability on a coarse scale level of problems with strongly varying and discontinuous coefficients defined on a fine scale. The upscaled permeability is defined as the solution of an optimization problem, where the difference between the fine scale and the coarse scale velocity field is minimized. We show that it is not necessary to solve the fine scale pressure equation in order to minimize the associated cost‐functional. Furthermore, we derive a simple technique for computing the derivatives of the cost‐functional needed in the fix‐point iteration used to compute the optimal permeability on the coarse mesh. Finally, the method is illustrated by several analytical examples and numerical experiments. This revised version was published online in July 2006 with corrections to the Cover Date.     

2210多协议路由器的配置及应用

介绍了IBM2210路由器的特点,配置方法及其在9210工程中的应用     

广西气象计算机网络的建设和发展

介绍广西气象计算机网络的过去,现状和将来发展方向.     

中国新生代成矿作用的惰性气体同位素研究与动力学背景

通过对中国不同类型的，与新生代成矿作用有关的地质样品的惰性气体同位素组成研究，揭示出在不同地质新生代地幔流体广泛地参与了不同类型的成矿作用的规律。壳幔相互作用在宏观上控制了成矿作用的发生，但在早第三纪和晚第三纪刚开始时，地幔脱气作用表现得更为显著。25Ma可能是一个重要的转折点，虽然不同部位或地段中记录的惰性气体同位素组成有时相对均一，有时变化很大，但无疑深大断裂带是幔源气体逸出的重要通道，也是控制新生代成矿作用的重要构造部位。