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1.
Grove Mountains (GRV)99027: A new Martian meteorite   总被引:10,自引:0,他引:10  
We report the petrography, mineral chemistry and oxygen isotopic composition of GRV 99027, a new Martian meteorite recently collected during the 16th Chinese Antarctic Research Expedition. This meteorite consists of two textural regions. The interstitial region is characterized by the presence of plagioclase and phosphate, and higher FeO contents of olivine and orthopyroxene, in comparison with the poikilitic region. All of the observations are similar to the three known Martian lherzolites. We classify GRV 99027 as the fourth sample of Martian lherzolite.  相似文献   

2.
《科学通报(英文版)》1998,43(6):504-504
A statistic model of predicting El Nio based on the multiple regression analysis is developed by using sea surface temperature anomalies in the NINO3 region (5°S-5°N), 90-150°W) as a predictant and the Asian meridional circulation index as the predictors. This model cannot only simulate most of El Nio during 1950-1980 (except for El Nio in 1965), but also hindcast 1982/1983, 1986/1987, 1991/1992 and 1994 El Nio and predict 1997/1998 El Nio six months in advance. At the same time, three different sample series (periods of 1950-1969, 1970-1989, 1950-1989) are used to examine the stability and skill of the statistic model. The models have successfully hindcasted and predicted El Nio before and after the selected samples except for the 1965 El Nio. In addition, the forecast in the El Nio year is clearly superior to that in the following year. The model prediction reaches the lowest skill during March to April.  相似文献   

3.
The white paper document titled“China’s Space Activities”,released in November2000by theInformation Office of the State Council,represents the first time for China to fully,systematically and publiclyintroduce to the world China’s space development strategy and concerned policies.Its release is a milestoneevent in the country’s space history,bearing great importance and profound influence to its future spaceefforts.The paper here describes the shaping processes of some important new ideas and concepts,includingthe connotative meaning of“space activities in a broad sense”and the roles and positions of different sectors insuch activities.It also briefly discusses related policies concerning the country’s space development and shortterm concepts and plans on its civil space activities.  相似文献   

4.
GMOs: The new hotspot in ecological research   总被引:2,自引:0,他引:2  
Gene flow is an important ecological and genetic process, and the fitness conferred by the insertion of a foreiga gene could be important in ecology after it becomes introgressed into the wild genetic background of organisms,which is the determinative factor for the fate of GMOs or foreign genes in natural ecosystem and for the competition with native species. Trophic interrelation fulfilled by food chains is the most important correlation between species in ecosystem and could be affected by the modified genotypes after the introduction of GMOs. The technology enabling the precise manipulation of genotype is a great opportunity for the stndy of ecological genetics in an unknown way prior to the biotechnology era. Especially interesting is the impact of genes on ecosystem function when GMOs are released into environment. A variety of ecological terminology has been frequently used in assessment of ecological risks related to the release of GMOs in environment, e.g. gene flow, fitness,interspecific competition and food chain. The value of GMOs in ecological research is illustrated through several examples in biasafety assessment related to those terms here. It is proposed that ecolegists should pay attention to the study of gene function in ecosystem and take the opportunity to enrich ecological theory with the release of GMOs.  相似文献   

5.
A shared-nothing spatial database cluster is system that provides continuous service even if some system failure happens in any node. So, an efficient recovery of system failure is very important. Generally, the existing method recovers the failed node by using both cluster log and local log. This method, however, cause several problems that increase communication cost and size of cluster log. This paper proposes novel recovery method using recently updated record information in shared-nothing spatial database cluster. The proposed technique utilizes update information of records and pointers of actual data. This makes a reduction of log size and communication cost. Consequently, this reduces recovery time of failed node due to less processing of update operations.  相似文献   

6.
Numerical weather prediction (NWP) has become one of the most important means for weather fore-casts in the world. It also mirrors a nation's comprehensive strength in meteorology. In 2000, China Meteorological Administration (CMA) established the National Innovative Base for Meteorological Numerical Prediction in the Chinese Academy of Meteorological Sciences (CAMS), to work on developing a new generation of the national operational NWP system――Global/Regional Assimilation and PrEdiction System (GRAPES), to enhance meteorological services in China in the new century. In recent years, the GRAPES has witnessed a fast development. The GRAPES has been set up as an integration of the model framework, data assimilation, regional and global NWP system, which can be commonly used for both operation and research. In this paper, a brief review is made for illustrating the GRAPES system, including the advanced designs of the GRAPES, its diverse applications in multifields, and efficiencies of the regional and global GRAPES in operational applications based on hindcast results.  相似文献   

7.
We performed an assimilation experiment of the southern South China Sea in summer 2000, and the altimeter data were assimilated into Princeton Ocean Model (POM). The result was evaluated with the in situ data. There were obvious improvements of the currents in the southern South China Sea, and the modeling uncertainty coming from the error of wind stress forcing was reduced. This experiment provides us a new idea about improving the modeling of the ocean currents.  相似文献   

8.
In natural resources, the forage plant resources are an importantpart of agricultural natural resources, and their contents are widerthan the concept of rangeland resources. The forage plants include notonly herbage but also shrubs and arbors taken in by livestocks. Theyare the cheapest forage for feeding livestocks and serve as the materialbasis for development of livestock industry. As forage plants are akind of living natural resources through long-term natural selectionand artificial cultivation, they contain rich heredity genes and serve  相似文献   

9.
Numerical weather prediction (NWP) has become one of the most important means for weather forecasts in the world. It also mirrors a nation's comprehensive strength in meteorology. In 2000, China Meteorological Administration (CMA) established the National Innovative Base for Meteorological Numerical Prediction in the Chinese Academy of Meteorological Sciences (CAMS), to work on developing a new generation of the national operational NWP system-Global/Regional Assimilation and PrEdiction System (GRAPES), to enhance meteorological services in China in the new century. In recent years, the GRAPES has witnessed a fast development. The GRAPES has been set up as an integration of the model framework, data assimilation, regional and global NWP system, which can be commonly used for both operation and research. In this paper, a brief review is made for illustrating the GRAPES system, including the advanced designs of the GRAPES, its diverse applications in multi-fields, and efficiencies of the regional and global GRAPES in operational applications based on hindcast results.  相似文献   

10.
0Introduction Scientists[14]havethoughtthatchangesinlandusecouldplayapivotalroleinenvironmentalchangesandcontributetoglobalchange,anditis perhapsthemostubiquitousofallenvironmentalchange.Withtheawarenessoftheimportanceofland usechangesonglobalenvironmentalchange,thestudyofregionalorgloballandusechangehasbecomethe focusofmuchscientificendeavorandinternational organizations[4,5].Forlanduseanditspatternsintegratingboththenaturalandhuman developed socioeconomicenvironments,itisagoodfocusforstudies…  相似文献   

11.
Based on the collection of land use maps of three repre sentative years (1972, 1986 and 1995) with a scale of 1 = 100 000, which were derived from interpreted aerial photographs and field surveys, landscape pattern were studied in Wenchuan County of Aba Prefecture, northwest of Sichuan Province, China, Six land use categories were classified according to the actuality of the study area and digitized by manual with the assistance of Geographic Information System (GIS). Landscape spatial and temporal changes were analyzed quanti ficationally by a series of structure, shape, pattern indices, which indicated that grassland dominates in number of patch while both grassland and shrub-land dominate in total area of patch over time. During the last 23 years, the fractal dimension of grassland and shrub-land were decreased while the other types were increased. Highest dominance and fragmentation and lowest diversity characterized the landscape of 1972. In 1986, the landscape pattern had the highest diversity and lowest dominance and fragmentation, which is contrary to the pattern in 1972, Slight change of diversity, dominance and fragmentation has been displayed from 1986 to 1995.  相似文献   

12.
The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids,such as α relaxation,slow β relaxation and fast β relaxation and so on.For the traditional theoretical system,α relaxation is believed mainly responsible for the nature of the glass transition as the beginning of the phenomenon.This idea,however,has been open to a big challenge since recent studies have indicated that slow β relaxation closely relates to α relaxation.Slow β relaxation determines the characterist...  相似文献   

13.
This paper studies current policies in compensation for land lost due to construction of the Three Gorges project (TGP), China. In the case study of Kaixian County, the value of land in the peri-urban areas is underestimated. Some losses in land are tangible and thus measurable, but some losses are intangible and thus immeasurable. The land available in the resettlement areas is scarce and rarely of equivalent quality. This study suggests that the loss of agricultural land be compensated with alternative land and/or non-land-based livelihood strategies, including part compensation in monetary terms and preferential policies.  相似文献   

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15.
Based on a comparison of the spatial extension modulus and speed of the two mega-polis cities in western China, Chongqing and Chengdu, the differences of urbanization characteristics of the two cities were analyzed. The results show that the two cities have different spatial extension modulus and extension speed. The extension speed of Chongqing, the largest mountainous city of China, was slow and its extension direction was along the Yangtze River valley and the Jialing River valley. Chengdu, the largest plain city of western China, had a faster extension speed than Chongqing and a concentric circles extent modulus. The spatial extent modulus and speed were controlled by the natural condition, especially the topography, the policies, the economic development level and the investment of the state central government.  相似文献   

16.
Usually, only crystalline basement is strong enough to store the massive strain energy that can be released in a damaging earthquake. By contrast, sedimentary cover is weak, because of its relatively high porosity and fluids. Therefore, it generally cannot accumulate enough energy for strong earthquakes. On January 31, 2010, a M5.0 earthquake occurred near the border of Suining and Tongnan in China. It excited strong short-period Rayleigh waves Rg, indicative of its shallow focal depth. The focal depth is constrained to less than 4 km, most probably in the range of 1-3 km, by modeling amplitude dependence on the frequency and waveforms of teleseismic depth phases (pP, sP). Because the local Mesozoic sedimentary cover is about 6 km thick, this earthquake should have occurred in the sedimentary cover. Though some shallow earthquakes with magnitudes up to M4 occur in Paleozoic sediments, this earthquake is the first M5 event studied in Mesozoic sedimentary cover. This event provides a rare opportunity to study seismogenic processes of damaging earthquakes in sedimentary basins.  相似文献   

17.
In China, the marine Jurassic is mainly distributed in the Qinghai-Tibetan Plateau, southwestern China and environs including southwestern Xinjiang and western Yunnan. Along the western palaeo-Pacific coast, marine Jurassic deposits, which usually intercalate with nonmarine strata, exist sporadically in eastern Heilongjiang, western Fujian, Hongkong, central Guangdong, western Jiangxi, eastern and southwestern Hunan Province, and probably also in western Taiwan. Nonmarine Jurassic strata are widely distributed in the whole of China except for southern Tibet area. They are commonly intercalated with volcanic rocks and contain volcanic materials in eastern China, and in southern Tibet. Marine strata yield various abundant fossils including ammonites, which were widespread in the Tethyan Realm even all over the world. Consequently, China is a critical region to attempt marine and non-marine Jurassic correlation. Through various investigations, both marine and non-marine Jurassic biozonations or assemblages have been established and by this the marine and non-marine Jurassic stratigraphic system and their correlation in China have been clarified.  相似文献   

18.
In China, the marine Jurassic is mainly distributed in the Qinghai-Tibetan Plateau, southwestern China and environs including southwestern Xinjiang and western Yunnan. Along the western palaeo-Pacific coast, marine Jurassic deposits, which usually intercalate with nonmarine strata, exist sporadically in eastern Heilongjiang, western Fujian, Hongkong, central Guangdong, western Jiangxi, eastern and southwestern Hunan Province, and probably also in western Taiwan. Nonmarine Jurassic strata are widely distributed in the whole of China except for southern Tibet area. They are commonly intercalated with volcanic rocks and contain volcanic materials in eastern China, and in southern Tibet. Marine strata yield various abundant fossils including ammonites, which were widespread in the Tethyan Realm even all over the world. Consequently, China is a critical region to attempt marine and non-marine Jurassic correlation. Through various investigations, both marine and non-marine Jurassic biozonations or assemblages have been established and by this the marine and non-marine Jurassic stratigraphic system and their correlation in China have been clarified.  相似文献   

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