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151.
Jongchul Chae Hyung-Min Park Kwangsu Ahn Heesu Yang Young-Deuk Park Jakyoung Nah Bi Ho Jang Kyung-Suk Cho Wenda Cao Philip R. Goode 《Solar physics》2013,288(1):1-22
For high resolution spectral observations of the Sun – particularly its chromosphere, we have developed a dual-band echelle spectrograph named Fast Imaging Solar Spectrograph (FISS), and installed it in a vertical optical table in the Coudé Lab of the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. This instrument can cover any part of the visible and near-infrared spectrum, but it usually records the Hα band and the Ca ii 8542 Å band simultaneously using two CCD cameras, producing data well suited for the study of the structure and dynamics of the chromosphere and filaments/prominences. The instrument does imaging of high quality using a fast scan of the slit across the field of view with the aid of adaptive optics. We describe its design, specifics, and performance as well as data processing 相似文献
152.
Geo-engineered buffer capacity of two-layered absorbing system under the impact of rock avalanches based on Discrete Element Method 总被引:1,自引:0,他引:1
Yu-zhang Bi Si-ming He Xin-po Li Yong Wu Qiang Xu Chao-jun Ouyang Li-Jun Su Hao Wang 《山地科学学报》2016,13(5):917-929
Many rock avalanches were triggered by the Wenchuan earthquake on May 12, 2008 in southwest China. Protection galleries covered with a single soil layer are usually used to protect against rockfall. Since one-layer protection galleries do not have sufficient buffer capacity, a two-layered absorbing system has been designed. This study aims to find whether an expanded poly-styrol (EPS) cushion, which is used in the soil-covered protection galleries for shock absorption, could be positioned under dynamic loadings. The dynamic impacts of the two-layered absorbing system under the conditions of rock avalanches are numerically simulated through a 2D discrete element method. By selecting reasonable parameters, a series of numerical experiments were conducted to find the best combination for the two-layered absorbing system. The values of the EPS layer area as a percentage of the total area were set as 0% (S1), 22% (S2), and 70% (S3). 22% of the area of the EPS layer was found to be a reasonable value, and experiments were conducted to find the best position of the EPS layer in the two-layered absorbing system. The numerical results yield useful conclusions regarding the interaction between the impacting avalanches and the two-layered absorbing system. The soil layer can absorb the shock energy effectively and S2 (0.4-m thick EPS cushion covered with soil layer) is the most efficient combination, which can reduce the impact force, compared with the other combinations. 相似文献
153.
四川省水土资源开发利用现状特征、问题及可持续利用对策 总被引:2,自引:0,他引:2
系统分析评价研究了2004年四川水土资源开发利用现状特征及其存在的主要问题,针对四川人地矛盾日趋尖锐、水土流失严重、水资源利用率低、水资源污染仍较严重尤其饮用水源地水质堪忧等制约全省经济社会可持续发展的重要因素,提出了实现四川水土资源可持续利用的对策和措施。 相似文献
155.
Vanja Bi?evac Erwin Krenn Dra?en Balen Fritz Finger Kadosa Balogh 《Mineralogy and Petrology》2011,102(1-4):163-180
Granitic pebbles occurring in the Permotriassic metasedimentary sequence of eastern Papuk, Slavonian Mountains, Croatia, were recognized to represent a coherent group of felsic, muscovite-albite metagranites. Fabrics, modal compositions and geochemical data imply that the rocks are derivatives of S-type granites formed through a combination of igneous and subsequent metasomatic processes. A Variscan formation age is demonstrated by K-Ar dating on coarse muscovite (range of 329?C317?Ma) as well as by electron microprobe based Th-U-Pb monazite dating (338?±?15?Ma). Additionally to the Variscan metasomatic processes of albitization and greisenisation, which led to an almost complete replacement of K-feldspar and biotite by albite and coarse muscovite, pebbles were affected by a younger phase of alteration resulting in the formation of a fine-grained sericitic matrix. The fine sericite yields K-Ar ages of 91?C83?Ma. A substantial reheating of the rocks during the Cretaceous is also indicated by the growth of new monazite dated at 106?±?10?Ma. Yttrium-contents of the Cretaceous monazite from the granite pebbles (0.3?C0.9?wt% Y2O3) are compatible with metamorphic temperatures of ~350?C400°C. These data confirm recent concepts according to which large parts of the Slavonian Mountains received a pervasive Cretaceous low-T regional metamorphic overprint. Furthermore, the pebbles provide useful information on the nature of the eroded Variscan crust of the Tisia Terrain, which has obviously contained considerable amounts of evolved high-level S-type granites modified through albitization and greisenization. 相似文献
156.
157.
WANG Xiu-fen CHEN Bai-ming BI Ji-ye 《中国地理科学(英文版)》2005,15(3):193-199
1IN T R O D U C T IO NAs we allknow,China isa countrywith vastpopulationand scarcelandpercapita(Y ANG and LI,2000)."T rea-suringlandverymuch,utilizinlgandrationallaynd pro-tectingthe cultivatedland conscientiously"is funda-mental statepolicyofChina.At the… 相似文献
158.
Genetic modification is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. Synechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid (GLA) and stearidonic acid (SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6D, Syd15D and Syd6Dd15D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in Synechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content. 相似文献
159.
TPC 及 DLC理论在旅游产品再开发中的应用——昆明市案例研究 总被引:22,自引:1,他引:22
从旅游产品再开发的角度出发,应用市场营销学的TPC理论和旅游地理学的DLC理论,对昆明市的病例进行分析,提出了昆明市旅游产品再开发战略的方向、原则和发展重点。 相似文献
160.
随着我国文化旅游的快速发展及喀什经济特区设立,地处喀什和阿克苏等地区的刀郎文化逐渐成为关注的重要内容。刀郎文化在其形成过程中不断融合蒙古族等其他民族的文化因子,逐步发展成为维吾尔民族独特的地域文化,在我国目前大力发展文化旅游的背景下,建立刀郎文化旅游区具有重要的现实意义。在对刀郎文化旅游区建立的必要性进行分析的基础上,从机遇、知名度和基础3个角度探讨了刀郎文化旅游区建立的可行性。在喀什经济特区背景下建立刀郎文化旅游区,需要打破行政区划限制,运用前台-帷幕-后台理论,设立三级支撑系统,彰显刀郎文化特色,突出民族和谐,并使刀郎文化旅游区与喀什经济特区进行整合式发展。 相似文献