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中国黄土区东亚古季风气候与冰期气候对比研究 总被引：2，自引：0，他引：2
岳乐平 《西北大学学报(自然科学版)》1998,28(2):157-162
研究了中国黄土区冰期气候与季风气候记录;进行了黄土磁化率与大洋δ１８Ｏ曲线对比,并且将黄土组合—古土壤组合与冰期－间冰期气候进行了比较。结果表明：黄土组合与古土壤组合记录了冰期气候与间冰期气候;中国黄土—古土壤堆积是全球冰期—间冰期气候变化与东亚古季风气候变化共同作用的结果。 相似文献
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Mn2+ EPR intensity recorded in the Chinese loess-paleosol sequence shows close correlation with magnetic susceptibility and Sr content as well as the oscillation of paleoclimate. Thus Mn2+ EPR signal can serve as an indicator sensitive to the East Asia summer monsoon intensity fluctuations. 相似文献
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应用免疫液流泳和对流免疫电泳技术对东亚钳蝎蝎毒进行了免疫检测技术研究。试验结果表明：上述两种试验技术在应用兔抗东亚钳蝎蝎毒血清进行蝎毒蛋白检测时是可行的、快速的、灵敏的。 相似文献
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应用电泳技术和免疫检测技术对我国分布最广、数量最多的东亚钳蝎的蝎毒蛋白进行了试验研究。结果表明：各蛋白组分能够有效地刺激家兔产生特异性抗体。应用琼脂扩散试验、免疫电泳试验、琼脂单相辐射免疫扩散试验、对流免疫电泳试验等试验方法对东亚钳蝎蝎毒进行检测是可行的。本研究可成为快速、灵敏、准确的东亚钳蝎蝎毒蛋白检测技术。 相似文献
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《科学通报(英文版)》1999,44(Z1):81-81
An investigation of rock magnetic properties using the temperature-dependence of susceptibility (TDS) and the coercivity of different IRM components was conducted on samples of the Malan loess (L1) and the last interglacial soil (S1) along an E-W transect of the Chinese Loess Plateau. We find that the behavior of the TDS is useful in identifying maghemite (γ-Fe_2O_3) in both loess and paleosol, and that it can be used as a new proxy of the degree of pedogenesis, which is closely linked to climatic conditions. Based on results from the TDS, we conclude that (1) the detrital magnetite grains predominate in the L1 unit to the west of Liupan Mts, where the weathering and pedogenetic processes were weakest; (2) a comparable degree of pedogenesis exists in the L1 at the east of the Liupan Mts and the S1 at the west of the Liupan Mts; (3) a higher concentration of maghemite is found in the S1 unit at the eastern sections, suggesting that the local climate was warmer and more humid in this interval. In addition, we propose that TDS measurements can be used as a rapid means of determining the reliability of the paleomagnetic secular variation (PSV) record in loess/poleoso/sequenees. 相似文献
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杨丽娟 《科技导报(北京)》2019,37(18):162-168
中国黄土独特的地层构造一直吸引着不同领域学者的注意。1949年后,黄土研究进入一个全新而系统的阶段。根据大量黄土研究材料,梳理了黄土研究在中国的发展脉络,总结了70年来黄土研究的重要成果。20世纪50-60年代的黄土普查获得了大量关于黄土地区的一手材料,陆续出版有重要影响力的黄土阶段性研究成果;20世纪70年代后,随着新技术与新方法的运用,黄土研究在内容与精度上不断得以丰富与完善;20世纪80年代至今,黄土高原水土流失综合治理研究取得诸多成果,更为重要的是,黄土地层记录的古气候密码逐渐被破解,成为理解全球气候变化的关键因素。在几代学者的共同努力下,中国黄土研究处于世界先进水平。 相似文献
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蔡养泉 《贵州师范大学学报(社会科学版)》2004,(6):30-35
地区主义是相对全球主义的一个国际现象,它既是一种理论,也是一种实践。在当前国际社会中存在着欧洲、北美、东亚三大地区主义中心,地区主义及其发展趋势成为当今国际关系研究中的一个热点。东亚地区也经历了从旧地区主义发展到新地区主义的阶段,然而东亚新地区主义所无法克服一系列困难,又使东亚地区面临着何去何从的问题。因此,目前地区主义发展的一种可能性———介入性地区主义应受到重视和关注。 相似文献
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Xiaomin Fang Zhentao Shi Shengli Yang Maodu Yan Jijun Li Ping’an Jiang 《科学通报(英文版)》2002,47(16):1381-1387
Eolian loess is widely distributed on the various geomorphic surfaces between 700–2400 m a.s.l. on the northern slope of the Tian Shan. It is formed in a synchronous manner with dust transported from the Gurbantunggut Desert in the Junggar Basin. The thickest section of loess was found in the Shawan and Shihezi regions. Paleomagnetic and climatic proxy analyses of over 71 m of a loess-paleosol sequence on the highest terrace of the Qingshui He (River) in the Shawan show that the paleomagnetic Bruhues/Matuyama (B/M) boundary lies at the bottom of paleosol S8, at a depth of 69.5 m, and the bottom of the sequence was estimated to be ∼0.8 Ma. This implies that the extremely dry climatic conditions in the Junggar Basin and the initial Gurbantunggut Desert were present at least by 0.8 Ma. High-resolution grain size series demonstrate that this area and desert expansion experienced two dramatic periods of desert expansions that occurred at ∼0.65 Ma and 0.5 Ma, respectively; and the subsequent continuous enhancement led to the environment presently observed. This tremendous environmental effect, caused by large-scale expansion of the desert and arid region of inner Asia, might be an important driving force for the global temperature drop that occurred in the mid-Pleistocene. 相似文献
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In the transitional region between the Loess Plateau and deserts, 4 sections located respectively at Yuling, Hengshan, Dingbian and Huining of China are studied. The high-resolution paleoclimatic records obtained show that environmental events on varying time scales have happened over East Asia. These events are dated with the time scales established using the recently-developed approach of Automatic Orbital Tuning. This leads to the establishment of the chronology of the environmental events. 相似文献
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阐述了重夯的作用机理,并结合山西省山阴至平鲁(晋蒙界)高速公路第二合同段(Ⅱ级非自重湿陷性黄土填方路段),通过现场选点试夯采集数据,分析了夯沉量和重夯前后压实度的检测结果,表明对于Ⅱ级非自重湿陷性黄土地基采用重夯法进行加固处理时,最佳的夯击次数是5次,其有效的夯实深度在4m,在该有效的深度范围内压实度均提高到92%以上,地基强度得到了提高,对于防止工后沉降有显著的效果. 相似文献
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基于台湾岛内自身的外向型经济特点和海峡两岸经济整合中的“磁吸效应”,在东亚区域经济整合的大背景之下,依靠中国大陆,进行“三通”,才是台湾未来经济发展战略的最佳选择。 相似文献
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《科学通报(英文版)》1999,44(Z1):64-64
Magnetite and maghaemite are the two main contributors to magnetic susceptibility in the Chinese loess/palaeosol sequence. Due to the close similarity in physical properties, early investigators treated them together as \"magnetite\". Utilising the property of thermally instability of maghaemite, we have been able to separate it from magnetite in loess and palaeosol samples from the upper parts of the Xifeng and Luochuan sections on the central Chinese Loess Plateau and compare its variation with depth and horizon. Our results indicate that thermally unstable maghaemite is relatively enriched in both 1) weakly weathered loess units and 2) towards the west, the direction of dust supply, suggesting that maghaemite is at least partially (coarse grains) of detrital aeolian origin while some pedogenic maghaemite (extra fine grains) occurs in the palaeosols. The physical meaning of magnetic susceptibility, therefore, needs to be reconsidered as a synthetic indicator reflecting the palaeoenvironment for both source area and deposition area. Thermally unstable goethite is a minor magnetic component of palaeosol samples, but it may play a significant role in determining characteristic magnetic remanence of weakly weathered loess samples, especially when one applies alternating-field cleaning. 相似文献
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《山海舆地全图》的复原研究 总被引：2，自引：0，他引：2
对已失传的《山海舆地全图》的历史线索进行了初步研究,采用北京大学图书馆提供的《舆地山海全图》的影印件为蓝本,初步绘制出了《山海舆地全图》的复原图。 相似文献
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中国正在从家电制造大国向家电技术强国方向迈进,其家电产品已销往世界各地,但韩国市场却仍是中国家电企业的"软肋"。究其因一是难敌韩国家电品牌,二是韩国消费者高度忠诚于本国品牌。因此,中国家电在韩国市场上必须采取相应的目标市场和定位战略,在迎合韩国家电市场消费需求和偏好的基础上,强化当地化营销策略和行动。 相似文献
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A local and global context representation learning model for Chinese characters is designed and a Chinese word segmentation method based on character representations is proposed in this paper.First,the proposed Chinese character learning model uses the semantics of local context and global context to learn the representation of Chinese characters.Then,Chinese word segmentation model is built by a neural network,while the segmentation model is trained with the character representations as its input features.Finally,experimental results show that Chinese character representations can effectively learn the semantic information.Characters with similar semantics cluster together in the visualize space.Moreover,the proposed Chinese word segmentation model also achieves a pretty good improvement on precision,recall and f-measure. 相似文献