Late quaternary monsoon patterns on the Loess Plateau of China

China's Loess Plateau was formed under special conditions. The tectonic movement, topographical characteristics, and monsoon patterns combined to create a favourable environment for the accumulation of thick loessic deposits. The Loess Plateau itself is part of the ‘Monsoon Triangle’ of China, a region very susceptible to climatic changes. Throughout the Upper Pleistocene the palaeoenvironment on the Loess Plateau alternated from steppe, to deciduous forest and coniferous forest, in response to shifts in the atmospheric circulation. Three monsoon patterns appear to be indicated: (1) a full glacial monsoon pattern (18000–15000 yr BP) which induced a cold and dry climate favouring loess accumulation in steppe conditions; (2) an interglacial monsoon pattern (last interglacial and Holocene) in which a warm humid climate prevailed with deciduous forests, leaving palaeosols interbedded within the loess sequence; and (3) a transitional or interstadial monsoon pattern (50 000–23 000 yr BP) in which the climate was cold and humid in the Loess Plateau, encouraging the development of coniferous forest.     

9 震前大气电场异常的物理基础

人们认识自然总是从实践到理论,再从理论到实践.没有理论指导的实践是盲目的实践,没有实践基础的理论是空洞的理论,只有理论与实践密切结合,才能有所发现,有所进步.     

Laboratory tests as a basis for the control of sewage sludge dumping at sea

Toxicity and bioaccumulation studies were carried out on a number of UK sewage sludges to determine whether laboratory experiments could be used to regulate sludge dumping at sea. Whilst the acute toxicity of sewage sludges to adult marine organisms was generally low, shrimp larvae were found to be up to 500 times more sensitive than adults of the same species. No significant bioaccumulation of mercury or cadmium could be detected following up to 60 days exposure of fish, shrimps and mussels to the most heavily contaminated sludges available, although there was some uptake of lead, zinc and copper.     

杭州地磁台方位角的复测检验

通过实际观测,描述了杭州地磁台方位角的检验结果,通过复测检验有两点认识:一种新技术新方法的应用,须经过不同方法的严格比较检验,验收合格后方可推广应用;如果采用简接法测定观测墩的方位角,其精度不完全决定于天文或GPS的观测精度,在很大程度上取决于水平角的观测精度.为此建议用此法测定观测墩的方位角,须有合理的观测程序和严密的观测技术,与此同时,尚须具备高于方位角精度要求的高精度精密光学经纬仪.     

土-结构动力相互作用的振动台试验研究综述

本文从土-结构动力相互作用振动台试验过程中所涉及的结构模型动力相似设计、模型土体的模拟及土体边界条件的模拟三个方面,回顾了近几年来土-结构动力相互作用振动台试验研究的发展历程与现状,重点描述了试验过程中为了更好地反映震动条件下土与结构动力相互作用的机理,学者们所采取的办法和措施。并在此基础上,介绍了一种新的研究土-结构动力相互作用的振动台试验技术。最后,总结了传统的土箱-振动台试验存在的不足,并与这种新的试验技术进行了对比,提出了对于这种新的试验方法仍需要进一步研究和解决的问题。     

Palynological constraints on the age of the Mississippi Valley-type Changdong Pb-Zn deposit,Sanjiang belt,West China

Mississippi Valley-type(MVT)Pb-Zn deposits serve as the world’s major supply of Pb-Zn resources.However,the age constraint of MVT Pb-Zn deposits has long been a big challenge,due to the lack of minerals that are unequivocally related to ore deposition and that can be used for radioisotopic dating.Here we show sporopollens can provide useful chronological information on the Changdong MVT Pb-Zn deposit in the Simao basin,Sanjiang belt,West China.The Pb-Zn ores in the Changdong deposit are hosted by internal sediments in paleo-karst caves of meteoric origin.Sphalerite and galena occur as replacements of carbonate minerals and void infillings in the internal sediments.The relations suggest that the Pb-Zn mineralization occurred after the deposition of the internal sediments.A palynological assemblage mainly composed of angiosperm pollen dominated by Castanea,Quercus,and Carya and fern spores dominated by Polypodiaceae,Pteris,and Athyriaceae was identified.These pollen and spores place the ore-hosting internal sediments and the Changdong paleo-karst at early to middle Oligocene.Consequently,the Changdong Pb-Zn deposit must have formed after the early Oligocene(~34 Ma).These age constraints,together with the geological characteristics,indicate that the Changdong Pb-Zn deposit is a paleo-karst-controlled MVT deposit related to fold-thrust systems in the Sanjiang belt.The Changdong deposit is similar to other MVT Pb-Zn deposits in the northern part of the Sanjiang belt,making it possible to extend this Pb-Zn belt 500 km further to the South.Results presented here highlights the potential of sporopollens in dating the age of MVT deposits related to paleo-karst formation in young orogenic belts.     

储液罐液—固—土耦合非线性翘离振动分析

本文考虑液固耦联及底板几何非线性与土壤弹性，建立了液－固－土耦合的储液罐翘离分析力学模型。算例表明，恢复力矩与翘离角之间的关系可以表达为分段线性，翘离将使地震响应增大。     

Geochemical constraints on the petrogenesis of basalts from eastern Jiangnan orogen, South China

The basalts crop out widely in the eastern part of late Proterozoic Jiangnan orogen. In terms of their petrographical and geochemical characteristics, they can be divided into two distinct types: low- and high-Ti. basalts. They crystallized from the magmas derived from the depleted upper mantle differing in partial melting degree. Project supported by the National Natural Science Foundation of China.     

深部地应力探测技术理论探讨

地应力测量的研究已有几十年的历史,但是对于地下深部地应力非钻孔式测量探测技术的发展,则一直进展很慢。本文依据天然电磁波场源,利用光弹实验模型原理,研制了ＤＹＬ型地应力探测仪,并在淮南地区地庆力状态普查过程中,取得了明显的应用效果。     

肺部良性肿块的CT表现

目的是分析了肺部良好性肿块的ＣＴ表现,探讨病变的鉴别诊断,方法用１０例病人中,硬化性血管瘤１例,孤立性肺囊肿２例,１０例均行常规胸部ＣＴ扫描,其中８例行增强扫描。结果得到硬化性血管瘤边缘光滑锐利,密度致密均匀,增强扫描强化特别明显,错构瘤呈爆花米样钙化或梅花瓣样钙化,呈浅分叶状,可有血管连接征,曲菌球,２例在空洞内呈游离状态,１例菌球占满空腔呈分叶状,形似肺癌,但增强扫描无强化,２例肺隔离症分别位