卫星介质深层充电的计算机模拟研究

卫星介质深层充电效应是诱发地球同步轨道卫星运行故障和异常的重要因素之一,文中介绍了介质深层充电的物理机制,给出了初步的物理模型和计算机模拟方法,该模型的模拟计算结果与欧空局的深层充电分析软件DICTAT的计算结果吻合得很好. 深层充电导致的最大电场总是出现在介质的接地侧,因此,介质的接地侧是发生放电的危险区域;对于典型的外辐射带高能电子能谱情况,介质的充电时间为小时量级.     

On the prediction of relativistic electron fluence based on its relationship with geomagnetic activity over a solar cycle

A study has been carried out to determine the relationship between high energy relativistic (>2 MeV) electron fluence and auroral zone geomagnetic activity for a solar cycle. Data for 1987–1997, spanning Solar Cycle 22, were used in the study. The relativistic electron fluence data were based on fluxes observed by the GOES geosynchronous satellites. The geomagnetic data were the DRX indices derived from a Canadian magnetic observatory located in the auroral zone at Fort Churchill, near the footprint of field lines passing through geostationary satellites. This work, based on data from a solar cycle, confirms earlier findings using limited data from segments of a solar cycle of enhancement in fluence 2–3 days after increases in geomagnetic activity, and shows the cycle dependence of fluence with respect to geomagnetic activity. This study underlines the influence of recurrent coronal holes on fluence level as well as the possible role of Pc5 magnetic pulsations as an electron acceleration mechanism, and highlights the predictability of fluence from ground geomagnetic data. A fluence prediction algorithm can now solely be based on derived expressions relating fluence and DRX. Thus, a simple fluence prediction scheme can easily be implemented to provide a 2–3 day advance warning of space weather conditions hazardous to geosynchronous satellites, since during days of high fluence, the likelihood of internal charging in a satellite is high, with possible discharges that could result in satellite operational anomalies. For verification purpose, daily values of fluence for 1997–2000 and for January 1994 were postcast using the derived expressions. The postcast values were validated, and the results give credence to the fluence prediction scheme.     

Tribo-electrostatic behaviour of high ash non-coking Indian thermal coal

The tribo-electrostatic method was applied to beneficiate non-coking Indian thermal coal from Ramagundam coal mines containing nearly 45% ash content. The microscopic studies revealed that quartz and kaolinite are the dominant minerals whereas illite, goethite, siderite and pyrite are the minor inclusions in the coal. Contact electrification of ash-forming minerals and coal matter was carried out using different tribo-charger materials of Al, Cu, brass, perspex and teflon. The Cu tribo-charger was found to be optimum to acquire differential charge between ash-forming inorganics and coal matter. The temperature effect on the magnitude of contact charge acquisition was found to be significant. Tests on a laboratory in-house built tribo-electrostatic free-fall separator with minus 300 μm coal showed that the ash content was reduced from 45% to about 18%, and a clean coal product as judged by the washability studies can be obtained. The results illustrate that the non-coking coals can be beneficiated using the scientific knowledge on the response and behaviour of coal and non-coal matters to electric charges.     

川中龙王庙组气藏多期充注特征及对寒武纪早期海相烃源岩发育的指示意义

为了研究古老超深层天然气藏的充注模式,探讨寒武纪早期海相烃源岩的质量、规模和寿命,笔者等选取高石梯—磨溪地区龙王庙组气藏作为研究对象,结合区域构造演化史和烃源岩生烃史,应用盐水包裹体均一温度与储集层埋藏史温度对比的方法,建立了充注模式,并追踪其烃源岩层位为下寒武统筇竹寺组;从寒武纪早期古气候、古环境和古生物等的角度,分析了该时期形成海相烃源岩的有机生产力和保存条件。研究显示,四川盆地超深层气藏的形成经历了古油藏、古裂解气藏和晚期干气的多期充注阶段,气藏充注来源于古油藏裂解气和超晚期源岩释放的天然气。这一事实指示了,早寒武纪的全球背景为高质量、大规模和长寿命的优质烃源岩发育提供了基础,对于四川盆地超级气盆地的形成提供了理论依据。     

电动汽车充电站选址研究进展

在电动汽车产业高速发展的科技浪潮中,充电站选址未来将成为城市发展战略布局不可或缺的一部分,深受交通工程、电力能源、管理学等各领域学者的广泛关注。已有的综述类文章缺乏对充电站选址相关研究进行全面梳理,论文利用CiteSpace软件对电动汽车充电站选址文献进行梳理,一方面归纳总结2009—2017年间国内外该研究主题的研究现状和热点,对其进行可视化分析;另一方面梳理充电站选址影响因素、选址方法和选址的成本-效益评估等研究内容,同时对国内外充电站选址研究的趋势予以简要介绍,厘清研究发展脉络,为充电站选址在地理学中的研究和实践提供方法和指引。未来,随着各地新能源汽车充电站选址研究的不断发展,有望在充电站选址布局中识别多元化和精细化充电需求和服务、统筹不同主体间成本-效益目标等方面不断完善,从而优化城市交通网络及基础设施布局,为新一轮的城市规划提供指引。     

AUV水下对接装置控制系统设计

自主式水下机器人(Autonomous Underwater Vehicle,简称AUV)在航行使命结束后需要回收至甲板或陆地进行补给和维护。为避免重复布放回收所带来的不便,根据锥形导向式回收原理,针对水下对接装置及其控制系统进行了设计。水下对接装置控制系统由水面控制终端,水下控制系统和水下外部设备等部分组成,使用超短基线引导AUV进入指定区域,在对接过程中依靠行程开关和无线电反馈的信息判断AUV的相对位置及状态,并通过驱动相应的液压机构对AUV姿态进行校正和固定,进而完成对接过程。水下对接装置在千岛湖进行了试验,在吊装水下7 m的情况下实现了AUV的水下对接,并利用湿插拔电连接器完成了对AUV的有线充电和数据上传。试验验证了对接方案的可行性以及控制系统的稳定性,为将来AUV能够进行长时间、不间断航行提供了可能。     

奥连特盆地斜坡带原油地化特征、充注模式及勘探实践

奥连特盆地斜坡带原油油品分布复杂,重质原油开发难度大、不经济,中轻质原油分布规律不清,严重制约斜坡带油气勘探.本文从原油地化分析入手,通过分析原油分布特征和地化特征,明确重油成因机理,建立原油充注模式,指出中轻质油有利发育区,以有效指导油气勘探.研究结果如下:(1)斜坡带原油正构烷烃具有前峰型碳分布形式,表明原油主要为...     

云内大粒子对闪电活动影响的个例模拟

利用三维云起电放电模式, 通过对2008年9月6日北京地区一次雷暴过程的模拟, 研究了云内雨滴、冰晶、霰和雹4种粒子对云内闪电活动的直接影响。对比几种主要冰相粒子比质量浓度的分布变化与模拟闪电开始发生高度的关系, 并分析几种冰相粒子所带电量变化率的时空变化特征后发现:霰和冰晶是对云内闪电发生作用最为重要的两种粒子; 雹粒子对闪电发生作用有限; 雨滴则对于主电荷区附近闪电发生没有直接影响。模拟结果表明:在实际观测中出现的雷达强回波达到某个高度之上可以预警闪电发生的现象, 主要是由于霰粒子在一定高度之上与冰晶之间发生强烈的电荷分离, 从而使云内电场迅速增强, 并最终引发闪电而导致的。     

Compositional heterogeneity of crude oil and its origin in the Linnan subsag, Linyi County, Shandong Province

The Linnan subsag is the main oil producer of the Linpan oil zone. Based on the oil group composition, gas chromatography data and biomarker analysis, it was indicated that crude oils from different oilfields varied greatly in group composition and showed obvious heterogeneities in the aspects of precursor type, crude oil maturity and hydrocarbon depositional environment. According to the characteristics of source rocks, three oil populations can be distinguished, i.e., the southern, northern and transitional oil populations. Furthermore, on the basis of post-reservoir reworking processes, the medium conditions of hydrocarbon-generating environment and differences in maturity, six oil families and twelve sub-families were distinquished. An integrated study suggested that the factors leading to such heterogeneities in crude oil composition mainly include different source rocks, multi-stage oil/gas charging, geo-chromatographic effects during oil/gas migration, reservoir heterogeneities and various post-reservoir secondary alterations.     

升平-兴城气田营城组火山岩储层流体包裹体研究

升平-兴城气田营城组火山岩储层经历多次构造活动,具有多期天然气的充注特征。采自该气田20口井45块岩芯样品的流体包裹体系统分析揭示了该区复杂的天然气充注过程。对各期次流体包裹体的均一温度、盐水包裹体的盐度,以及含烃盐水包裹体的荧光强度等测试的综合分析表明,火山岩储层经历了6期热流体活动,前4期分别对应于4期天然气充注过程。结合埋藏史分析可知,4期充注分别发生于泉头组沉积末期-青山口组沉积时期、嫩江组沉积早-中期、嫩江组沉积末期和明水组沉积早期至今。综合考虑生烃层、储层和盖层之间的组合关系,最终确定升平-兴城气田营城组火山岩储层天然气主要的成藏时期为嫩江组沉积早-中期。