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11.
Sensitivity of vegetation indices to atmospheric aerosols: continental-scale observations in Northern Asia 总被引:1,自引:0,他引:1
Xiangming Xiao Bobby BraswellQingyuan Zhang Stephen BolesStephen Frolking Berrien Moore III 《Remote sensing of environment》2003,84(3):385-392
Satellite observations play an important role in characterization of the interannual variation of vegetation. Here, we report anomalies of two vegetation indices for Northern Asia (40°N-75°N, and 45°E-179°E), using images from the SPOT-4 VEGETATION (VGT) sensor over the period of April 1, 1998 to November 20, 2001. The Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), which are correlated to a number of vegetation properties (e.g., net primary production, leaf area index), were compared. The results show that there is a large disagreement between NDVI and EVI anomalies in 1998 and 1999 for Northern Asia. The NDVI anomaly in 1998 was largely affected by atmospheric contamination, predominantly aerosols from extensive forest fires in that year. The EVI anomaly in 1998 was less sensitive to residual atmospheric contamination, as it is designed to be, and thus EVI is a useful alternative vegetation index for the large-scale study of vegetation. The EVI anomaly also suggests that potential vegetation productivity in Northern Asia was highest in 1998 but declined substantially in 2001, consistent with precipitation data from 1998-2001. 相似文献
12.
松辽盆地是位于中国东北的大型白垩系陆相含油气盆地,前人普遍认为其形成和演化主要受西太平洋板块向西俯冲作用的影响和控制。那么,环西太平洋构造带仅在中国东北形成大型坳陷盆地的动力机制是什么,松辽盆地在坳陷阶段之前发育火石岭组和营城组2套断陷期火山岩的诱因是什么,中国东北地区大规模发育中生代岩浆岩的主控因素是什么。显然,这些现象很难单纯用古太平洋板块活动控制来解释。本文在充分吸收已有科研成果的基础上,从区域动力学背景、火山岩时空分布特征以及沉积盆地构造演化的角度,分析了蒙古-鄂霍茨克洋东段的闭合对松辽盆地形成与演化的影响,指出蒙古-鄂霍茨克洋关闭是中生代东北亚最重要的一次大地构造事件,板块的俯冲、碰撞、挤压、拉张以及岩浆活动等作用对该区盆-山格局的形成和演化都具有重要的影响;并提出了松辽盆地可能存在的蒙古-鄂霍茨克洋和西太平洋板块双向俯冲成因模式,厘定了两者对中国东北地区多期次挤压和拉张作用的转换时间,从全新的角度认识了松辽盆地的形成和演化过程,合理地诠释了中国东北部晚侏罗世-早白垩世有别于西太平洋南部地区的岩浆岩发育特征。 相似文献
13.
多个构造带的复合叠加过程及其形成的地质结构是陆内构造变形研究的前沿问题。松辽盆地南部梨树断陷处于古亚洲洋构造域与太平洋构造域的交接位置,是研究这一问题的良好窗口。小宽断裂带是梨树断陷内具有代表性的构造单元,与区域内的油气藏关系密切,其地质结构和演化过程仍存在争议。研究通过开展三维地震数据解释和地震相干切片分析厘定了小宽断裂带的地质结构和演化过程;通过总结前人认识和区域大地构造演化背景分析了走滑-逆冲活动的成因机制及其油气地质意义。研究结果认为:(1)小宽断裂带整体向西倾,可分为南段、中段、北段3部分;(2)在早白垩世,小宽断裂带经历了早期伸展构造变形和末期左行走滑-逆冲构造变形,断裂带的走滑-逆冲构造活动导致梨树断陷中央构造带内形成多个背斜;(3)小宽断裂带形成于中国东北地区由古亚洲洋构造域主导向太平洋构造域主导的转换过程,受控于早白垩世晚期古太平洋板块的加速俯冲;(4)小宽断裂带走滑-逆冲构造活动所形成的背斜构造是梨树断陷中央构造带内油气富集的重要构造。小宽断裂带南段发育封闭性良好的背斜构造,生-储-盖条件较好,具有成为梨树断陷下一步勘探方向的潜力。 相似文献
14.
Hu Hou Bafang LiXue Zhao Yongliang ZhuangGuoyan Ren Mingyan YanYangpeng Cai Xiukun ZhangLi Chen 《Food chemistry》2009
Gelatin was extracted from Pacific cod (Gadus macrocephalus) skin and hydrolysed sequentially with pepsin and alkaline protease. The hydrolysates were fractionated into two ranges of molecular weight (PEP1: 2000 Da < Mr < 6000 Da; PEP2: Mr < 2000 Da) using ultrafiltration membranes. In this present study, we investigate the protective effects of both polypeptides against ultraviolet radiation-induced skin photoaging by the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and the contents of glutathione (GSH), malondialdehyde (MDA), hydroxyproline (HYP) in photoaging skin tissue. The arrangement of collagen fibres in skin tissue was examined by Van Gienson stain. UV radiation-induced decrease in the antioxidase activity and depletion of reduced glutathione (20.4%) in the skin of hairless mice in a model group. Compared with the model, both polypeptides can enhance the activities of SOD, GSH-Px, CAT and the contents of GSH and HYP, and reduce the content of MDA, which minimised the skin photo damage. Moreover, the results of histology study confirmed that both polypeptides could protect collagen fibres in skin. 相似文献
15.
南传佛教是泰、缅、柬、老等东南亚国家以及我国傣族地区具有主体地位的宗教形态,普及面广、信徒众多、影响深刻。作为其重要组成部分的南传佛教壁画,可谓是中南半岛上最具典型意义的美术形式。它既是信奉南传佛教信众的情感流露和心灵写照,又是其精神世界与审美理想的表征。本文依托田野考察所获取的一手资料及相关文献,对东南亚南传佛教壁画的历史沿革、内容题材、形式风格、表现手法和发展现状等进行了梳理与分析。 相似文献
16.
Solar energy is accessible throughout the year in tropical regions. The latest development of absorption chillers has demonstrated that these systems are suitable for effective use of solar energy. The utilisation of solar energy for heat-driven cooling systems has significant advantages. Without a doubt, solar energy represents a clean energy source that is available without any additional fuel cost, and that can be proportionally accessible when the cooling load increases during the middle hours of the day. This study focuses on a single-double-effect absorption chiller machine that was installed in Indonesia. The system is driven by a dual-heat source that combines gas and solar energy. This system is characterised by simulating its performance in various conditions in terms of the cooling water (28–34 °C) and the hot water (75–90 °C) inlet temperatures. The reference operating condition of this system is 239 kW of cooling capacity. The mathematical model is validated and shows a good agreement with experimental data. In the operative range considered, simulation results yield a coefficient of performance between 1.4 and 3.3, and a gas reduction ratio from 7 to 58% when compared to a double-effect absorption chiller driven by gas. Based on the simulation results, this system is expected to have a good potential for widespread use in tropical Asia regions. 相似文献
17.
This article introduces and provides the context for the themed section on mobile communication in Asia. It suggests that much work remains to be done in adequately grasping the new mobile, mediated face of communication in the very diverse Asian region. It also suggests that such a new direction in research needs to go hand in hand with rethinking the conceptual and theoretical bases of mobile, and indeed, Internet and computer‐mediated communication. 相似文献
18.
Effect of monosodium glutamate on physicochemical properties and quality of Alkali‐treated Pacific white shrimp
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Soottawat Benjakul Passakorn Kingwascharapong 《International Journal of Food Science & Technology》2016,51(8):1827-1833
Physicochemical properties and quality of Pacific white shrimp (Litopenaeus vannamei) treated with alkaline soaking solution (ASS; 0.75% NaOH with 2.5% NaCl) containing 3% monosodium glutamate (MSG), pH 11.5 (ASS+3% MSG) were investigated, in comparison with those treated with mixed phosphates or ASS alone. Muscle proteins underwent conformational changes as evidenced by the shift of Tmax to the lower temperature and the increased negative charge when treated with ASS+3% MSG. This coincided with the higher moisture and NaCl contents (P < 0.05). Such a treatment led to the pronounced swelling of muscle fibrils as visualised by scanning electron microscope. Highest likeness score for all attributes except for flavour was observed in sample treated with ASS+3% MSG. Slightly fishy odour in the treated sample was associated with higher abundance of volatile compounds, especially alcohol and aldehyde. Thus, ASS+3% MSG could be used as the replacer of phosphate and bicarbonate for shrimp processing. 相似文献
19.
Lipids from cephalothorax and hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) stored in ice for up to 6 days were extracted and characterised. The extraction yields of lipids from hepatopancreas (10.65–12.64%) were higher than those from cephalothorax (2.59–2.88%). However, no changes in the extraction yield were observed during the storage (p > 0.05). The carotenoid contents of lipids from cephalothorax and hepatopancreas slightly increased within the first 2 and 4 days of iced storage (p < 0.05), respectively, but decreased thereafter (p < 0.05). With increasing storage time, a progressive formation of hydroperoxide was found as evidenced by the increase in the absorbance band at 3600–3200 cm−1 in Fourier transform infrared (FTIR) spectra, and increased peroxide values (PVs) (p < 0.05). The increases in thiobarbituric acid reactive substances (TBARS), p-anisidine value (AnV) and free fatty acid (FFA) content of lipids were noticeable when iced storage time increased (p < 0.05). Those changes indicated that lipid oxidation and hydrolysis occurred in both samples. Phospholipids (PL) were the major components in lipids from cephalothorax (82.51% of total lipids). Nevertheless, lipids from hepatopancreas contained triglyceride (TG) and PL as the dominant components (45.35% and 38.03% of total lipids, respectively). A decrease in the TG content with a concomitant increase in free fatty acid was observed at the end of storage (day 6) (p < 0.05). Decreases in unsaturated fatty acids, especially eicosapentaenoic acid (EPA; C20:5(n-3)) and docosahexaenoic acid (DHA; C22:6(n-3)) were noticeable at day 6 of storage (p < 0.05). Thus, the extended storage time resulted in the enhanced deterioration of extracted lipids. 相似文献
20.
《Energy Policy》2014
Following the dissolution of the Soviet Union, various gas pipeline projects have been proposed to diversify transit routes and export markets of the landlocked Central Asian states. To evaluate the pipeline project's impact on the players' bargaining power, I apply the cooperate game theory to a quantitative model of the Eurasian gas trade and quantify the bargaining power structure via the Shapley value. Due to ample production capacities in Central Asia, I observe little strategic interaction between the West and China. Thus, demand competition with China is not necessarily a disadvantage for the West, and the Turkmenistan–China pipeline does not affect the impact of the westbound projects aiming Europe and Turkey. For Turkmenistan, i.e., the main supplier in the region, a link via the Caspian Sea to Turkey is the most beneficial westbound option. Although the projects carrying gas from Azerbaijan and Turkmenistan to Europe enjoy the European Commission's political support, they yield marginal benefits to the European consumers. Thanks to its transit position, Turkey collects a large share of the benefits in the East–West gas trade. 相似文献