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Based upon the effect of land-sea interaction on the paleomonsoon variation and the time series of climatic proxy-indicators, the historical Asian monsoon variation over the last 130,000 and 18,000 years has been reconstructed with an emphasis on the basic characteristics of summer monsoon circulation. The monsoon-climatic cycles and associated model of environmental development over the central and eastern China are proposed and the mechanism of paleomonsoon variation of China preliminarily discussed. The variation of East Asian monsoon circulation should be regarded as a regional result of both solar-radiation changes and the global glacial-interglacial cycles. The episodic uplifting of the Qinghai-Xizang Plateau since the late Miocene has to a large extent controlled the forming and evolution of the paleomonsoon circulation of China.  相似文献   
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Two types of the regular copolymer of poly (1, 4-phenyleneterephthalamide) were synthesized by the low temperature solution polycondensation in NMP-CaCl_2 solvent system, using the piperazine or 2,5-dimethylpiperazine as the third components introduced in the main chain of poly (1, 4-phenyleneterephthalamide). The properties of copolymers were characterized by IR, SEM, X-RAY diffraction, polarizing microscopy, TGA and solubilities.Experimental results showed that the copolymers had good solubility and thermal stability, the concentrated sulfuric acid (~98% ) solution of regular PPTA copolymers had liquid crystalline proper-  相似文献   
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最近130ka中国的古季风——Ⅱ.古季风变迁   总被引:27,自引:0,他引:27  
根据海陆相互作用对古季风变迁的影响和代用气候指标的时间序列,初步重建了最近130ka和18ka东亚季风变迁的历史,重点阐述了夏季风环流活动的基本特征,提出了中国中、东部季风气候旋回及有关环境过程模式,初步探讨了我国古季风变迁的机制。  相似文献   
4.
The characteristics of the modern monsoon climate o?China may be used as clues for recognizing the records of paleomonsoon climate. The present paper deals primarily with the various paleomonsoon records of the last 130,000 years in the southeast monsoon area. These records mainly come from the following three fields: (i) the historical, (ii) the geological, including loess-paleosol sequence, deserts, lakes, snowlines, timberlines, the phenomena of continental desertization and so on, and (iii) the biological, presented by vegetation and mammals. Among these records, the loess-paleosol sequence in the Loess Plateau reflects a climatic history characterized by alternation of two different climatic periods when the Asian winter monsoon and summer monsoon showed pronounced effects on environment, respectively.  相似文献   
5.
The solution polycondensation of 1,4-phenylenediamine hydrochloride and terephthaloyl chlo-ride with introducing a tertiary amine in NMP-CaCl_2 solvent system were studied in detail.Effect of reactant concentration, the content of CaCl_2, in NMP solvent and the kinds of tertiary amineon inherent viscosity of PPTA polymer have been studied. High molecular weight PPTA withinherent viscosity over 5 was obtained at 0.35Mol/L of reactant concentration in a solvent of NMP-CaCl_2 with the presence of α-picoline.  相似文献   
6.
最近130ka中国的古季风——Ⅰ.古季风记录   总被引:24,自引:0,他引:24  
现今中国季风气候的特点可以作为辨认古季风气候记录的线索。文中着重阐述最近130ka东南季风区的各种古季风记录,它们主要是:历史记录,包括黄土-古土壤序列、沙漠、湖泊、雪线和林线、大陆架沙漠化现象等的地质记录,由植被和哺乳动物代表的生物记录。其中,黄土高原的黄土-古土壤序列反映了过去亚洲冬季风和夏季风的环境效应突出气候期相互交替的历史。亚洲古季风变迁是中国古气候和古环境变迁的一个重要控制因素。  相似文献   
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<正> 聚对苯二甲酰对苯二胺(PPTA)具有刚性链分子结构,能形成各向异性的高分子液晶溶液,纺丝后可得到性能优异的高模量、高强度的纤维。但是,欲制出高模高强的PPTA纤维,必须先制出高分子量的PPTA聚合体。等曾研究了对苯二胺盐酸盐与对苯二甲酰氯在二甲基乙酰胺-氯化锂(DMAC-LiCl)溶剂体系中合成PPTA的问题。  相似文献   
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The potyelectrolyte of propane sulfonate(PS) grafted PPTA copolymers——PPTA-PS, PPTA[O]-PS, PPTA[C]-PS were prepared and used as electrolyte in the process of electrochemical polymerization of pyrrole to form the molecular composite polypyrrole (PPY)/Polyelectrolyte.The preparation and liquid crystalline property of three kinds of polyelectrolyte, the electrical conductivity, mechanical properties, SEM and thermoproperties of PPY/polyelectrolyte are presented in detail.  相似文献   
10.
本文以 1 ,8萘酰亚胺为原料 ,合成了两种萘酰亚胺类型的化合物 ,系统地研究了它们在不同溶剂中的吸收光谱和荧光光谱 .并以这两种化合物单体为基础 ,通过共聚合成了它们与甲基丙烯酸甲酯和N 乙烯基咔唑的嵌段共聚物 .研究了聚合物在溶液和薄膜中的荧光性质 .研究结果证明 ,所得共聚物不但保持了单体的基本荧光特性 ,其溶解性、成膜性、热稳定性等都得到了大大改善 ,是一种有应用前景的有机发光半导体材料 .此外 ,本文还利用荧光猝灭的手段研究了萘酰亚胺类化合物与C60 之间的相互作用 .  相似文献   
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