上海天文台白天人卫激光测距的强光保护     

张忠萍  肖炽Kun 《中国科学院上海天文台年刊》1994,(15):143-147

在进行白天激光测距实验中，太阳及其附近的强背景光会损坏测距系统的光电接收器件。本讨论了由本站自行设计并已在实际测距工作中使用的软件和硬件保护措施，同时给出了一个软件保护的图形实例，从显示的图形实例和实际使用都证明了所采用的保护措施是有效的。  相似文献   

Quantitative Study of the Morphological Variations among Dzieduszyckia Populations from the Devonian Rongxian Formation, South China and their Influencing Factors     

LI Tong  DONG Lin  SUN Yuanlin  YUAN Zhiwei  NIE Ting  LING Kun 《《地质学报》英文版》2023,97(6):1604-1615

The rhynchonellide brachiopod Dzieduszyckia Siemiradzki is widely distributed in the Lower Famennian strata, and exhibits a wide range of morphological variations among populations. 1272 autochthonous Devonian Rongxian Dzieduszyckia fossils were collected from three populations in South China, namely the Dazhai, Dalong, and Longmi sections. A series of quantitative morphological analyses were conducted to understand the morphological variation among populations and identify the triggers responsible for such variations. The results show that the Dazhai population differs significantly in morphospace from the Dalong and Longmi populations, while the latter two exhibit more similar morphological features, suggesting that geographic distribution may play a key role in affecting Dzieduszyckia morphology. The Longmi population shows a distinct morphospace from the Dazhai population and an overlapped morphospace with the Dalong population, indicating that habitat may not be the controlling factor. Lastly, the Dazhai and Dalong populations share some morphological similarities, but the Dazhai and Longmi populations occupy completely different morphospaces, indicating that evolution had a greater impact on phenotypic divergence than habitat. Our findings suggest that geographic distribution is the predominant factor influencing the morphological variation of Dzieduszyckia, while evolution and living habitat are less significant, the former of which might play a more important role.  相似文献   

Enrichment conditions and distribution characteristics of lacustrine medium-to-high maturity shale oil in China     

ZHAO Wenzhi  ZHU Rukai  LIU Wei  BIAN Congsheng  WANG Kun 《地学前缘》2023,30(1):242-259

Successful breakthroughs have been made in shale oil exploration in several lacustrine basins in China, indicating a promising future for shale oil exploration and production. Current exploration results have revealed the following major conditions of lacustrine shale oil accumulation: (1) stable and widely distributed shale with a high organic abundance and appropriate thermal maturity acts as a fundamental basis for shale oil retention. This shale exhibits several critical parameters, such as total organic carbon content greater than 2%, with optimal values ranging from 3% to 4%, kerogen Ⅰ and Ⅱ₁ as the dominant organic matter types, and vitrinite reflectance (R_o) values greater than 0.9% (0.8% for brackish water environments). (2) Various types of reservoirs exhibiting brittleness and a certain volume of micro-nanoscale pores are critical conditions for shale oil accumulation, and these reservoirs have porosities greater than 3% to 6%. Moreover, when diagenesis is incipient, pure shales are not favorable for medium-to-high maturity shale oil enrichment, whereas tight sandstone and hybrid rocks with clay content less than 20% are favorable; however, for medium-to-late-stage diagenesis, pure shales with a clay content of 40% are favorable. (3) The retention of a large amount of high-quality hydrocarbons is the factor that best guarantees shale oil accumulation with good mobility. Free hydrocarbon content exceeding a threshold value of 2 mg/g is generally required, and the optimum value is 4 mg/g to 6 mg/g. Moreover, a gas-oil ratio exceeding a threshold value of 80 m³/m³ is required, with the optimal value ranging from 150 m³/m³ to 300 m³/m³. (4) High-quality roof and floor sealing conditions are essential for the shale oil enrichment interval to maintain the overpressure and retain a sufficient amount of hydrocarbons with good quality. Lacustrine shale oil distributions exhibit the following characteristics: (1) major enrichment areas of shale oil are located in semi-deep to deep lacustrine depositional areas with external materials, such as volcanic ash fallout, hydrothermal solutions, and radioactive substances with catalytic action, as inputs; (2) intervals with “four high values and one preservation condition” govern the distribution of shale oil enrichment intervals; and (3) favorable assemblages of lithofacies/lithologies determine the distribution of enrichment area. According to preliminary estimates, China has 131×10⁸ to 163×10⁸ t of total shale oil resources with medium-to-high thermal maturity, among which 67×10⁸ to 84×10⁸ t is commercial. These resources are primarily located in the Chang 7¹⁺² interval in the Ordos Basin, Qing 1+2 members in Gulong sag in the Songliao Basin, Kongdian and Shahejie formations of Cangdong sag, Qikou sag and the Jiyang depression in the Bohai Bay Basin, and Lucaogou Formation in the Junggar Basin.  相似文献   

Precipitation recycling ratio and water vapor sources on the Tibetan Plateau     

Kun YANG  Qiuhong TANG  Hui LU 《中国科学:地球科学(英文版)》2022,(3)

Precipitation recycling ratio(i.e.,evaporation-precipitation feedback strength)and water vapor sources are two key aspects of regional water cycle,and their quantification is essential for understanding water cycle processes and their changes.The results of existing studies on the precipitation recycling ratio and water vapor sources for the Tibetan Plateau were highly controversial.This article clarifies different frameworks for understanding the water cycle.It points out that(1)the ratio of evaporation to precipitation depends mainly on climate regimes,while the precipitation recycling ratio is closely related to both the climate regimes and the scale of the region of interest,and(2)the water vapor sources depend on the traced period(precipitating or non-precipitating period)and the degree of tracing.Within the same theoretical framework,there is no fundamental conflict among the results of different studies on the water cycle in the Tibetan Plateau.  相似文献   

Geochemistry, Zircon U–Pb Dating and Hf Isotopic Characteristics of Neoproterozoic Granitoids in the Yaganbuyang Area, Altyn Tagh, NW China     

CHEN Hongjie  WANG Nan  WU Cailai  LEI Min  ZHENG Kun  ZHANG Xin  GAO Dong 《《地质学报》英文版》2018,92(4):1366-1383

The South Altyn continental block is an important geological unit of the Altyn Tagh orogenic belt, in which numerous Neoproterozoic granitoids crop out. Granitoids are mainly located in the Paxialayidang–Yaganbuyang area and can provide indispensable information on the dynamics of Rodinia supercontinent aggregation during the Neoproterozoic. Therefore, the study of granitoids can help us understand the formation and evolutionary history of the Altyn Tagh orogenic belt. In this work, we investigated the Yaganbuyang granitic pluton through petrography, geochemistry, zircon U–Pb chronology, and Hf isotope approaches. We obtained the following conclusions:(1) Yaganbuyang granitoids mainly consist of two-mica granite and granodiorite. Geochemical data suggested that these granitoids are peraluminous calc–alkaline or high-K calc–alkaline granite types. Zircon U–Pb data yielded ages of 939±7.1 Ma for granodiorite and ~954 Ma for granitoids, respectively.(2) The εHf(t) values of two–mica granite and granodiorite are in the range of-3.93 to +5.30 and-8.64 to +5.19, respectively. The Hf model ages(TDM2) of two-mica granite and granodiorite range from 1.59–.05 Ga and 1.62–2.35 Ga, respectively, indicating that the parental magma of these materials is derived from ancient crust with a portion of juvenile crust.(3) Granitoids formed in a collisional orogen setting, which may be a response to Rodinia supercontinent convergence during the Neoproterozoic.  相似文献   

Movement and variation of four typical glaciers in the Qilian Mountains, northwestern China     

ZheFan Jing  Kun Wang  Li Liu 《寒旱区科学》2015,7(3):206-211

We selected four typical glaciers in the Qilian Mountains and investigated their movements and variation using advanced technologies such as remote sensing,photographic measurements,and global positioning systems.The velocity of glacier movements in the Qilian Mountains is relatively low,and there has been no significant variation during the past 50 years.Glacier motion has maintained a normal style.The movement velocity of Laohugou Glacier No.12 presented a decreasing trend(by 48%) from 1960 to 2012.The movement velocity of the Qiyi Glacier also presented a decreasing trend(by 48.1%) from 1958 to 2012; it decreased by 29.4% from 1958 to 1977 and by 26.5% from 1977 to 2012.Therefore,the Qiyi Glacier's movement velocity varied greatly over the earlier 20 years(1958–1977),but presented a small decreasing trend during the latter 30 years(1977–2012).By comparing the movement velocity variation of these typical glaciers,we determined that the extent of variation was consistent among large glaciers(such as Laohugou Glacier No.12) and small glaciers(such as the Qiyi Glacier and Yanglonghe Glacier No.5),despite their different sizes.  相似文献   

Diversity and distribution of bacterial community in the coastal sediments of Bohai Bay, China     

WANG Liping  ZHENG Binghui  LEI Kun 《海洋学报(英文版)》2015,34(10):122-131

In order to understand the diversity and distribution of the bacterial community in the coastal sediment of the Bohai Bay,China,high-throughput barcoded pyrosequencing of the 16 S r RNA gene was used.Metagenomic DNA was extracted from the sediment samples,and was sequenced using a 454 GS FLX Titanium system.At 97%similarity,the sequences were assigned to 22 884 operational taxonomic units(OTUs) which belonged to 41 phyla,84 classes,268 genera and 789 species.At the different taxonomic levels,both the dominants and their distribution varied significantly among the six coastal sediments.Proteobacteria was the first dominant phylum across all the six coastal sediments,representing 57.52%,60.66%,45.10%,60.92%,56.63% and 56.59%,respectively.Bacteroidetes was the second dominant phylum at Stas S1,S2 and S4,while Chloroflexi was the second dominant phylum at Stas S3,S5 and S6.At class level,γ-Proteobacteria was the first dominant class at Stas S1,S2,S4 and S6,while δ-Proteobacteria became the first dominant class at Stas S3 and S5.In addition,a large proportion of unclassified representatives have distributed at the different taxonomic levels.Canonical correspondence analysis(CCA) results indicated that the sediment texture,water depth(D),dissolved oxygen(DO),total nitrogen(TN) and nine EPA priority control polycyclic aromatic hydrocarbons(PAHs) including naphthalene,acenaphthylene,acenaphthene,fluorine,phenanthrene,fluoranthene,pyrene,benzo[a]anthracene and indeno[1,2,3-cd]pyrene were the important factors in regulating the bacterial community composition.Those results are very important to further understand the roles of bacterial community in the coastal biogeochemical cycles.  相似文献   

Development and application of simulation technique for hydrokinetic hammer     

Tianye ZHU  Qingyan WANG    Kun YIN    Siyi WANG. College of Construction Engineering  Jilin University  Changchun  China. Key Laboratory of Underground Information Detection Technology  Ministry of Education  Changchun  China 《东北亚地学研究》2007,10(2):196-202

The computer simulation is an important method for hydrokinetic hammer design. Various kinds of simulation measures with their technical characters and applications being taken during the computer aided design are enumerated. Computer simulation supports plenty of valuable references to the designer. Each type of simulation process is used to explore the exact aspect of the performance of hydrokinetic hammer and each type of simulation method has its own excellences and deficiencies. Thus the integrative simulation methods based on modern computational technology are brought forward to obtain the perfect capability of the whole product. Along with the development of computer hardware and software, various kinds of platforms have been provided to different simulation methods that can be carried out with distinct working flows. The jet flow element is the core part of the hydrokinetic hammer. We can build the ideal simulation model of it by means of CFD (computational fluid dynamics) technology. On the other hand, to set up the digital model of piston and hammer, the best way is to build the virtual prototype using automatic dynamic analysis of mechanical system. As a result of the argumentation, we think the technique of Virtual Prototype and CFD are the prime way to process the combined computer simulation for hydrokinetic hammer.  相似文献   

Field survey around strong motion stations and its implications on the seismic intensity in the Lushan earthquake on April 20,2013简     

Yefei Ren  Kun Ji  Ruizhi Wen  Xutao Huang 《地震学报(英文版)》2013,(Z1):241-250

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关于日地空间等离子体物理研究的前景     

朱岗Kun 《时间频率学报》1990,13(1):77-80

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