Millennial and orbital variations of El Niño/Southern Oscillation and high-latitude climate in the last glacial period

The El Ni?o/Southern Oscillation (ENSO) phenomenon is believed to have operated continuously over the last glacial-interglacial cycle. ENSO variability has been suggested to be linked to millennial-scale oscillations in North Atlantic climate during that time, but the proposals disagree on whether increased frequency of El Ni?o events, the warm phase of ENSO, was linked to North Atlantic warm or cold periods. Here we present a high-resolution record of surface moisture, based on the degree of peat humification and the ratio of sedges to grass, from northern Queensland, Australia, covering the past 45,000 yr. We observe millennial-scale dry periods, indicating periods of frequent El Ni?o events (summer precipitation declines in El Ni?o years in northeastern Australia). We find that these dry periods are correlated to the Dansgaard-Oeschger events--millennial-scale warm events in the North Atlantic climate record--although no direct atmospheric connection from the North Atlantic to our site can be invoked. Additionally, we find climatic cycles at a semiprecessional timescale (approximately 11,900 yr). We suggest that climate variations in the tropical Pacific Ocean on millennial as well as orbital timescales, which determined precipitation in northeastern Australia, also exerted an influence on North Atlantic climate through atmospheric and oceanic teleconnections.     

石墨烯国际发展态势分析

石墨烯最早由英国曼彻斯特大学科学家于2004年成功制备,因其集优异的力学、热学、电学和磁学性能于一身,迅速成为近年来材料科学和凝聚态物理领域的研究热点之一。随着对其制备、性质研究的不断深入,应用领域日益扩大。该文主要从国际相关研究计划、相关科学研究进展、SCI论文统计分析等几个方面对石墨烯国际发展态势进行了分析,最后提出了我国石墨烯材料与技术的发展对策与建议。     

电流互感器变比试验方法

通过对电流互感器等值电路的分析，讨论了两种电流互感器变比的试验原理及特点，提出了用电压检查电流互感变比的现场试验只需1个调压器、1块电压表、1块电流表简单实用的试验方法。     

羊三木油田低阻油层测井评价方法

针对羊三木油田低阻油层.综合地质、钻井特征,对低阻油层成因进行了分析,认为该区低阻油层主要是由于薄层、高束缚水饱和度储层引起.针对羊三木油田的实际情况.提出了区域构造对比法、自然电位减少系数法等低阻油层定性评价方法和针对高束缚水饱和度的双水法、针对薄层处理的高分辨率处理技术等定量评价方法.     

油田二次开发储层精细描述方法研究

厚油层层内非均质是二次开发储层精细描述的重点.以大港油区二次开发先导区羊三木油田为例,在单砂层级地层精细对比及沉积微相研究基础上,对厚油层进行细分研究.重点识别层内夹层,采用储层构型分析的思路,建立厚油层细分三维地质模型,将厚砂层分为多个相对独立的流动单元,并利用水淹层解释、剩余油饱和度监测井等手段,描述厚油层层内剩余油分布.     

The trophic fingerprint of marine fisheries

Biodiversity indicators provide a vital window on the state of the planet, guiding policy development and management. The most widely adopted marine indicator is mean trophic level (MTL) from catches, intended to detect shifts from high-trophic-level predators to low-trophic-level invertebrates and plankton-feeders. This indicator underpins reported trends in human impacts, declining when predators collapse ("fishing down marine food webs") and when low-trophic-level fisheries expand ("fishing through marine food webs"). The assumption is that catch MTL measures changes in ecosystem MTL and biodiversity. Here we combine model predictions with global assessments of MTL from catches, trawl surveys and fisheries stock assessments and find that catch MTL does not reliably predict changes in marine ecosystems. Instead, catch MTL trends often diverge from ecosystem MTL trends obtained from surveys and assessments. In contrast to previous findings of rapid declines in catch MTL, we observe recent increases in catch, survey and assessment MTL. However, catches from most trophic levels are rising, which can intensify fishery collapses even when MTL trends are stable or increasing. To detect fishing impacts on marine biodiversity, we recommend greater efforts to measure true abundance trends for marine species, especially those most vulnerable to fishing.     

基于蚂蚁算法的断裂自动解释技术在黄珏南地区的应用

在对地震资料进行预处理并综合应用相干体技术、方差体技术等多种地震属性技术检测地震反射不连续性的基础上,应用蚂蚁追踪技术对黄珏南地区三维地震资料进行断裂系统的自动解释,基于断裂自动解释结果提取黄珏南地区的三维断片系统,并将自动解释成果与人工解释方案进行对比。结果表明:在应用方差体技术对地震反射不连续性进行检测的基础上进行蚂蚁追踪得到的属性体断裂痕迹显示更加清晰直观,可以有效地指导断裂的平面及剖面解释;黄珏南地区主要发育一组近东西走向的断裂,呈阶梯状展布,断面北倾,一般倾角较大;蚂蚁追踪解释的主要断裂发育特征基本符合构造成因机制预测的断裂发育规律,这进一步验证了方法的实用性和有效性。     

晶种分解过程αk的变化

对烧结法和拜尔法种分槽的αk与△αk的变化过程进行了概述。αk和△αk的变化对氢氧化铝晶体长大有显著的影响，因此控制种分槽αk和△αk变化非常重要。     

盾构机刀盘驱动控制系统的设计与应用

介绍了以PLC做控制器、工控机做监控器、S120为执行器,构成刀盘的驱动控制系统。进而在盾构机刀盘驱动性能的要求下,设计出刀盘驱动控制系统,阐述了主从控制方式,实现主从传动的负荷均衡分配功能,保证机械受力的均匀和一致性。从而实现设备的安全、可靠运行。