Geochronology of source materials from high-pressure and ultrahigh-pressure metamorphic rocks in Jurassic sedimentary rocks of Hefei Basin

Eclogite cobbles were discovered by Wang et al. (2001) in the Fenghuangtai Formation of the northern margin of Dabie Mountains in the Dushan area of Anhui Province, China[1]. They proposed that after the formation during the Triassic, the high-pressure (HP) and ultra-high-pressure (UHP) metamorphic rocks reached the sur-face through exhumation and uplifting before the late Ju-rassic. However, they have not provided any evidence about isotopic ages. One kind of cobbles of HP-UHP rocks w…     

Effects of historical land cover changes on climate

In order to explore the influence of anthropogenic land use on the climate system during the last mil- lennium, a set of experiments is performed with an Earth system model of intermediate complexity—— the McGill Paleoclimate Model (MPM-2). The present paper mainly focuses on biogeophysical effects of historical land cover changes. A dynamic scenario of deforestation is described based on changes in cropland fraction (RF99). The model simulates a decrease in global mean annual temperature in the range of 0.09-0.16℃, especially 0.14-0.22℃ in Northern Hemisphere during the last 300 years. The responses of climate system to GHGs concentration changes are also calculated for comparisons. Now, afforestation is becoming an important choice for the enhancement of terrestrial carbon sequestration and adjustment of regional climate. The results indicate that biogeophysical effects of land cover changes cannot be neglected in the assessments of climate change.     

～4.1 Ga xenocrystal zircon from Ordovician volcanic rocks in western part of North Qinlin80rosenic Belt

High-precision U-Pb dating by in situ LA-ICP-MS yields an age of 4079±5 Ma for a xenocrystal zircon from Ordovician volcanics of the Caotangou Group in western part of the North Qinling Orogenic Belt. As a result, the North Qinling Orogenic Belt becomes one of a few localities in the world that contain Hadean age records （4276±6 Ma and 4404±8 Ma detrital zircons from Jack Hill of the Yilgarn craton, 4016 Ma Acasta gneisses of the Wopmay Orogeny and Burang quartzite with detrital zircon of 4103 Ma in Tibet）. It is also the first report of the Hadean age in Phanerozoic volcanics. The finding of the 4.1 Ga xenocrystal zircon provides not only the geochronological record of the oldest crustal materials in China, but also the condition for further search for rocks forming in the region during the early time of the Earth＇s evolution. Thirty-six zircon U-Pb dates from the Ordovician volcanic rocks are subgrouped into seven generations that represent different tectono-magmatic events in the North Qinling Orogenic Belt. Among them, two periods of 0.9--1.5 Ga and 0.4--0.5 Ga are consistent with Mesoproterozoic and Early Paleozoic orogenies, respectively.     

基于LabVIEW的造气炉温度辨识系统的研究

通过对造气炉的结构特点和反应机理分析,以及对测温干扰的估计,采用带受控项自回归滑动平均模型(CARMA)来表征其温度特性较为理想,但这种算法复杂,较难实现。基于任何CARMA模型都可以用高阶带受控项的自回归模型(CAR)逼近到任何精度,实现起来却又相对简单的特点,以LabVIEW为平台来完成对气化层温度的任意高阶CAR建模,能够很好的解决气化层温度难以直接测量的问题。     

骨盆内移截骨加植骨造盖治疗大龄儿童先天性髋关节脱位

目的：研究一种大龄儿童先天性髋关节脱位的新术式,为解决大龄儿童先天性髋关节脱位、头臼不称、即股骨头大、髋臼小,用其他术式无法覆盖包容股骨头的问题.方法：骨盆内移截骨加植骨造盖及粗隆下短缩旋转截骨术治疗头臼不称的大龄儿童先天性髋关节脱位.结果：本组15例,据周永德评定标准,除有2例髋关节屈曲活动受限、1例轻度股骨头坏死外,其余均为优良,无一例半脱位及全脱位.结论：大龄先天性髋关节脱位的头臼不称、头大臼小、真假臼相连者可以推广应用骨盆内移加植骨造盖术,其优点在于单纯骨盆内移术所不能解决的真臼边缘与近端不能很好衔接的问题.     

基于卫星遥感机理模型和陆面模式的土壤含水量同化研究

土壤湿度在陆气相互作用过程中扮演着重要的角色，是气候、水文、农业、林业等研究中重要的地球物理参数之一。土壤湿度影响地面蒸散，径流、地表反射率、地表发射率以及地表感热和潜热通量，从而对气候有重要影响，它对大气的影响在全球尺度上仅次于海面温度，在陆地尺度其影响超过海面温度。     

Phase equilibria of HP–UHP mica-schists in Jiangling, Eastern Dabieshan orogen

The HP–UHP metamorphic terrane of Jiangling, eastern Dabieshan comprises extensively distributed granitic gneisses, mica-schists and numerous eclogite blocks. The mica-schists generally contain garnet, phengitic muscovite, biotite, plagioclase, quartz, rutile and a small amount of epidote and hornblende. Study on petrography and phases equilibria in the NCKMnFMASH system indicates that the present mineral assemblages in mica-schists are not in equilibrium. The earlier stage of mineral assemblage represented by garnet and phengite reflects a HP–UHP condition. The garnet compositions and the phengite Si contents give a PT condition of 580–600℃ at 2.6–2.8 GPa. The garnet zonation records an earlier progressive metamorphic process which may be associated with the appearance of glaucophane, jadeite and lawsonite. The later stage of mineral assemblage characterized by the presence of biotite and plagioclase reflects a PT condition of 620–635℃ at 0.9–1.1 GPa, belonging to the HP amphibolite facies. The main mineral assemblage in micaschists from the Jiangling region has recorded a complete HP–UHP metamorphic process.     

内置式可控偏心器伺服平台稳定控制模型

在细化结构的基础上，对内置式可控偏心器的各个部分进行了受力分析，在此基础上构造了滚动稳定平台的控制模型，确定了内置式可控偏心器滚动稳定控制模型，为系统的后续分析提供了依据。     

新技术提升哈勃望远镜能力

正据美国宇航局网站报道,著名的哈勃空间望远镜到现在已经24岁了。一款空间望远镜能服役超过20年应该算是非常古老的玩意,但哈勃空间望远镜仍然在为我们呈现更加惊人的宇宙深空照片,并展开各种宇宙观测的研究。而今,天文学家们采用了一种名为"空间扫描"的新技术,其可以极大地提升哈勃望远镜的观测     

“黔中隆起”的发生发展与古风化壳铝土矿的形成问题

“黔中隆起”的结果形成了“黔中古陆”、“黔北古陆”,也形成“川东南古陆”,这些都是上扬子古陆的组成部份。只不过黔中地区地壳上升的幅度要大些。为什么“黔中古陆”地壳上升的幅度比“黔北古陆”以至“川东南古陆”上升的幅度要大一些呢?这主要是湘黔古断裂的关系(廖士范,1989)。这条古断裂呈南西西——北东东方向分布,西端清远地区是早石炭世的古风化壳铝土矿直接覆盖在中寒武世高台组或中上统娄山关