Apple disease samples were collected from the southern Xinjiang and annotated to design a convolutional neural network model based on deep learning.The accuracy and robustness of the model was improved through trainin...Apple disease samples were collected from the southern Xinjiang and annotated to design a convolutional neural network model based on deep learning.The accuracy and robustness of the model was improved through training and optimization algorithms,and a complete apple disease identification system was developed with the model as the core,and evaluated for its performance in terms of accuracy,recall rate and speed.This study provides a reliable AI-based apple disease diagnosis solution for the apple planting industry in the southern Xinjiang,hoping to help farmers better manage and protect crop health.展开更多
At present,the lack of Chinese culture in higher vocational English teaching in southern Xinjiang is serious.The existing English curriculum system is not enough to support the goal of cultivating ethnic minority coll...At present,the lack of Chinese culture in higher vocational English teaching in southern Xinjiang is serious.The existing English curriculum system is not enough to support the goal of cultivating ethnic minority college students cultural confidence,and its curriculum ideological and political construction is still in the initial stage of exploration.The combination of the Chinese national culture and the ethnic culture of Xinjiang and the ideological and political elements organically integrated into cultural confidence have endowed the vocational English education in Xinjiang with the characteristics of the times.In this paper,from the perspective of China s"cultural confidence",ideological and political elements were explored,and the background of ideological and political construction in higher vocational English teaching course in southern Xinjiang was analyzed;it is expounded that the ideological and political construction is an inevitable requirement for the high-quality development of vocational English education in southern Xinjiang,and the content design and implementation path of higher vocational English course was explored to provide new ideas and new ways for the curriculum ideological and political construction of higher vocational English teaching in southern Xinjiang.展开更多
Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature (SST). Most previous studi...Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature (SST). Most previous studies focused on the monsoon regions in East China, and only a few laid emphases on arid environments. In Xinjiang, which is located in Northwest China, the climate is typically arid and semi-arid. During the past 20 years, the pre- cipitation in Xinjiang has shown a significant increasing trend, and it is closely related to oasis irrigation. This paper aims at discussing whether abnormal soil moisture in spring can be the signal to forecast summer precipitation. The effects of abnormal soil moisture due to farm irrigation in spring in arid environments on regional climate are inves- tigated by using a regional climate model (RegCM3). The results indicate that positive soil moisture anomaly in irrigated cropland surface in May led to an increase in precipitation in spring as well as across the whole summer. The impact could last for about four months. The effects of soil moisture on the surface air temperature showed a time-lagging trend. The summer air temperature declined by a maximum amplitude of 0.8℃. The increased soil moisture could enhance evaporation and ascending motion in the low troposphere, which brought in more precipi- tation. The soil moisture affected regional weather and climate mainly by altering the surface sensible and latent heat fluxes.展开更多
With the implementation of the "13^(th) Five-Year Plan" to promote the border area and raise rural living standards, the Xinjiang Production and Construction Corps has paid more and more attention to the dev...With the implementation of the "13^(th) Five-Year Plan" to promote the border area and raise rural living standards, the Xinjiang Production and Construction Corps has paid more and more attention to the development of protected agriculture, which is needed for the comprehensive development and stability of the border groups. In this paper, the current status of greenhouse tomato production in Aksu of southern Xinjiang is analyzed and summarized, finding the following: the structure is not reasonable with poor performance; the soilless cultivation mode is gradually developed, and there are innovative forms; the fertilization structure is not reasonable and needs improvement; the technical level is low, and it needs to be upgraded. Therefore, to solve the various problems that exist at present, some efforts are needed achieve a better production model.展开更多
The tomato production facilities in southern Xinjiang have unique climatic conditions.However,due to the high salinity and degree of mineralization of the soil and the extensive management of irrigation water sources,...The tomato production facilities in southern Xinjiang have unique climatic conditions.However,due to the high salinity and degree of mineralization of the soil and the extensive management of irrigation water sources,the tomato production efficiency is low,and there is still much room for improvement.In this study,the formulas of tomato nutrient solutions were adjusted according to the local irrigation water quality characteristics,and tomato was grown in a greenhouse using sand cultivation.To select a nutrient solution formula suitable for the tomato cultivated in the local facilities,various parameters of tomato treated with different formulas were compared.The results showed the following:①Adjusting the nutrient solution formula could effectively improve the vegetative and reproductive growth indexes of tomato.②Properly decreasing the nutrient solution concentration could improve the growth indexes of tomato.③Decreases in Ca^(2+) and Mg^(2+) in the nutrient solution did not affect the growth and yield of tomato.The possible reason for the third result was that excessive cations in the water inhibited the absorption of Ca^(2+) and Mg^(2+) in the nutrient solution and had antagonistic effects.Therefore,a high nutrient solution concentration does not necessarily promote the growth of tomatoes.In summary,this study will improve the production conditions of protected tomato in the southern Xinjiang area by supporting tomato nutrient solution adjustments according to actual conditions in combination with reasonable irrigation systems and scientific management.展开更多
In the context of Development of the West Regions, by using the annual data from 1999 to 2009 in whole China and 12 provinces of the western regions, we analyze the achievements of socio-economic development of Xinjia...In the context of Development of the West Regions, by using the annual data from 1999 to 2009 in whole China and 12 provinces of the western regions, we analyze the achievements of socio-economic development of Xinjiang Uygur Autonomous Region from 1999 to 2009 as follows: the economic aggregate has increased prominently and the growth rate is increasing ceaselessly; the primary industry, secondary industry and tertiary industry develop evenly, and the industrial structure is incessantly optimized; the quality of economic growth is promoted increasingly and the living standard of people is improved greatly; the primary industry, secondary industry and tertiary industry stride in tandem, and the momentum of growth is strong. We conduct horizontal comparison on the main economic indicators of Xinjiang, 12 provinces of the western regions and whole China, which include GDP and its growth rate, investment of fixed assets, structure of the primary industry, secondary industry and tertiary industry, the industrial added value, GDP per capita, gross retail sales of social consumption, export and import trade, net income per capita of peasants and herdsmen, and general budget revenue. The result shows that although the implementation of the strategy of Development of the West Regions and the economic development of Xinjiang have achieved some remarkable results, there is a conspicuous gap in comparison with the expected effect. The problems existing in the operation of Xinjiang's economy are analyzed as follows: the industrial level is low, and the economic growth mode is yet to be transformed; the disposable income per capita of urban residents grows slowly, and the increasing gap between the urban areas and rural areas has no trend of dwindling; the investment aggregate is very low, and the momentum of economic growth is short. In order to make the central government and 19 provinces and cities offer pointed aid for Xinjiang, promote the implementation of new strategic development of Western China, and promote the better economic development of Xinjiang in the period of the Twelfth Five-Year Plan, we put forward some feasible suggestions as follows: Xinjiang should grasp favorable opportunities and quicken the pace of industrial structural adjustment; continue to open up to the outside world unswervingly, and improve investment environment ceaselessly; strive to maintain the continuous and rapid development of economy, and improve the living standard of people.展开更多
BACKGROUND^(14)C urea breath test(^(14)C UBT)and immunohistochemical staining(IHC)are widely used for detection Helicobacter pylori(H.pylori)infection with different sensitivity,and there is a difference in H.pylori i...BACKGROUND^(14)C urea breath test(^(14)C UBT)and immunohistochemical staining(IHC)are widely used for detection Helicobacter pylori(H.pylori)infection with different sensitivity,and there is a difference in H.pylori infection rate in Uyghur and Han ethnic groups.Both need large cohort studies to evaluate the differences more accurately.AIM To analyze the difference between^(14)C UBT and IHC for H.pylori detection in Xinjiang Uyghur Autonomous Region and the difference between Uyghur and Han populations.METHODS There were 3944 cases of H.pylori infection detected by both IHC and^(14)C UBT at the same time(interval<1 wk,with sampling site including gastric antrum,selected from 5747 patients).We compared the sensitivity of^(14)C UBT and IHC.We also compared 555 pairs of Han/Uyghur cases(completely matched for gender and age)for their H.pylori infection rates.The overall H.pylori infection rate of all 5747 cases and the correlation with other clinicopathological data were also further analyzed.SPSS V23.0 software was used for statistical analysis.RESULTS The sensitivity was 94.9%for^(14)C UBT and 65.1%for IHC,which was a significant difference(n=3944,P<0.001).However,among those cases negative for H.pylori by^(14)C UBT(detection value≤100),4.8%were positive by IHC.Combining both methods,the overall H.pylori infection rate was 48.6%(n=5747),and differences in gender,age group,ethnicity and region of residence significantly affected the H.pylori positive rates.According to age group(Han/Uyghur),the positive rates were≤30 years(62.2%/100.0%),31-40 years(45.2%/85.7%),41-50 years(47.2%/79.2%),51-60 years(44.6%/76.1%),61-70 years(40.9%/68.2%),71-80 years(41.7%/54.1%)and≥81 years(42.9%/NA).The H.pylori infection rates of Han/Uyghur paired cases were 41.4%and 73.3%,which was a significant difference(P<0.001)(555 pairs).H.pylori positivity was significantly related to moderate-severe grade 2-3 chronic/active gastritis and intestinal metaplasia(all P<0.05).CONCLUSION The sensitivity of^(14)C UBT was significantly higher,but combined application can still increase the accuracy.The prevention H.pylori should be emphasized for Uygur and young people.展开更多
Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka'erjiao intrusion is mainly composed of albite granite porphyry, K-feldspar granite porphyry, ivernlte and granite porphyry. Being a transitional pr...Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka'erjiao intrusion is mainly composed of albite granite porphyry, K-feldspar granite porphyry, ivernlte and granite porphyry. Being a transitional product between magma intrusion and eruption in the Sawur region, the Ka'erjiao intrusion was formed at the telophase of the late Carboniferous to the begining of early Permian as determined by the SHRIMP U-Pb zircon dating, with an age of 302.6±7.6 Ma (1 σ). The intrusion consists of alkali-enriched rock, whose REE distribution patterns are of the LREE enrichment type, the δEu value is low and Nd, St, Pb isotopes reflect its mantle source characteristics. The δ^18O value of intrusion is low as a result of isotope exchange with meteoric water. The geochemical characteristics show that it was formed in a post-collisional tectonic setting. Taking combined considerations of current studies of A-type granites and Permian volcanic rocks, we think that in the telophase of the late Carboniferous to the beginning of the early Permian, the Sawur region was within the extension or compressional to extensional period of a post-collisionai stage. The Ka'erjiao intrusion from mantle sources can confirm the vertical continental crust growth in the late Paleozoic. The Sawur region in west Junggar is consistent with east Junggar in post-collisionai tectonic evolution process.展开更多
Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'a...Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'an area of Shaanxi Province was firstly discovered. This deposit is currently in a detailed investigation stage, and no detailed study has been yet conducted. This work selected one molybdenite sample from the Be (W) ores in this deposit for Re-Os isotope measurements to define the time limit of tungsten and beryllium mineralization, and to further reveal the ore-forming geological setting of rare metals in the southern Qinling region.展开更多
Grassland is a major carbon sink in the terrestrial ecosystem. The dynamics of grassland carbon stock profoundly influence the global carbon cycle. In the published literatures so far, however, there are limited studi...Grassland is a major carbon sink in the terrestrial ecosystem. The dynamics of grassland carbon stock profoundly influence the global carbon cycle. In the published literatures so far, however, there are limited studies on the long-term dynamics and influential factors of grassland carbon stock, including soil organic carbon. In this study, spatial-temporal substitution method was applied to explore the characteristics of Medicago sativa L. (alfalfa) grassland biomass carbon and soil organic carbon density (SOCD) in a loess hilly region with different growing years and management patterns. The results demonstrated that alfalfa was the mono-dominant community during the cutting period (viz. 0-10 year). Community succession began after the abandonment of alfalfa grassland and then the important value of alfalfa in the community declined. The artificial alfalfa community abandoned for 30 years was replaced by the S. bungeana community. Accordingly, the biomass carbon density of the clipped alfalfa showed a significant increase over the time during 0-10 year. During 0-30 year, the SOCD from 0-100 cm of the soil layer of all 5 management patterns increased over time with a range between 5.300 ± 0.981 kg/m2 and 12.578 ± 0.863 kg/m2. The sloping croplands had the lowest SOCD at 5.300 ± 0.981 kg/m2 which was quite different from the abandoned grasslands growing for 30 years which exhibited the highest SOCD with 12.578 ± 0.863 kg/m2. The ecosystem carbon density of the grassland clipped for 2 years increased 0.1 kg/m2 compared with the sloping cropland, while that of the grassland clipped for 10 years substantially increased to 10.30 ± 1.26 kg/m2. Moreover, the ecosystem carbon density for abandoned grassland became 12.62± 0.50 kg/m2 at 30 years. The carbon density of the grassland undisturbed for l0 years was similar to that of the sloping cropland and the grassland clipped for 2 years. Different management patterns imposed great different effects on the accumulation of biomass carbon on artificial grasslands, whereas the ecosystem carbon density of the grassland showed a slight increase from the clipping to abandonment of grassland in general.展开更多
ccording to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)].τ0 values for i...ccording to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)].τ0 values for intermediate and small earthquakes occurred in Chinese mainland and Southern California have been calculated by use of these equations. The results demonstrate that the level and distribution of τ0 are closely related to the location where large earthquakes will occur, i.e. the region with higher level of τ0 will be prone to occur large earthquakes and the region with lower level will usually occur small earthquakes. According to the spatial distribution of τ0 , the seismic hazard regions or the potential earthquake source regions can in some degree be determined. According to the variation of τ0 with time, the large earthquake occurrence time can be roughly estimated. According to the distribution of τ0 in Southern California and variation with time, three high stress level regions are determined, one (Goldfield area) of them is the present seismic hazard region.展开更多
To study the dynamic changes of land use and predict the future land use scenarios based on the current land use,this paper uses Cellular Automata- Markov( CA- Markov) model to simulate the landscape pattern in 2030. ...To study the dynamic changes of land use and predict the future land use scenarios based on the current land use,this paper uses Cellular Automata- Markov( CA- Markov) model to simulate the landscape pattern in 2030. The results show that in the study area during the period 1980- 2005,grassland and construction land increased,and woodland increased slightly; waters and unused land decreased,and arable land underwent dramatic changes. The simulation precision of CA- Markov model is 87. 28%,indicating that the use of it for simulation is reliable. The land use of the study area will be changed greatly in the future. This method provides a reference for the regions to carry out land prediction,and the research results can provide a basis for the study of optimization of land.展开更多
This study presents the changes in lake areas in the Valley of Lakes, the Govi region, southern Mongolia. The recent changes in lake areas show decreases depending on vulnerability of lake basins and response of Govi ...This study presents the changes in lake areas in the Valley of Lakes, the Govi region, southern Mongolia. The recent changes in lake areas show decreases depending on vulnerability of lake basins and response of Govi landscape to the present climatic warming. During the recent 44 - 45 years (from 1970 to 2014 or 2015), modern lakes have encountered the present rapid increase in temperature, water evaporation and drying up that induced the reduction in lake areas in the Valley of Lakes. The finding of the reduction in lake areas is consistent with the trends on increasing in temperature since 1995 and fluctuating precipitation since 1975. Investigations with detailed chronology of lake sediment are needed from the lakes to review a more complete evolution of lake basins during the Late Quaternary paleoclimatic history in Mongolia and Central Asia.展开更多
[Objective] The present experiment was conducted to investigate the yield,adaptability and quality characteristics of Pennisetum purpureum Schumach cv. Purple to provide reference for the certification and development...[Objective] The present experiment was conducted to investigate the yield,adaptability and quality characteristics of Pennisetum purpureum Schumach cv. Purple to provide reference for the certification and development of new varieties.[Method] With P. purpureum Schumab cv. Purple as experimental material, the variety comparison tests were conducted in Nanning, Lingyun, and Tiandeng in Guangxi from 2007 to 2009, and variety regional trials were conducted in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Its comprehensive characters of plant height, hay yield, stem-leaf ratio and nutritional components were determined, and were compared with those of P. purpureum × P.americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin. [Result] The average height of P. purpureum Schumach cv. Purple was 706.54 cm, which was5.92% and 8.44% lower than that of P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin, respectively. The average hay yield of P. purpureum Schumach cv. Purple was 32.74 t/ha in Nanning, Lingyun, and Tiandeng of Guangxi from 2007 to 2009, and 22.41 t/ha in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Although its hay yield was lower than two control varieties, the difference was not significant(P 0.05).The stem-leaf ratio of P. purpureum Schumach cv. Purple was 0.98:1. Moreover,the analysis on the nutritional components of dry matter showed that compared with P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv.Guiminvin, the crude fiber of P. purpureum Schumab cv. Purple was decreased by4.76% and 2.78%, respectively; the neutral detergent fiber decreased by 5.07% and2.22%, respectively; the acid detergent fiber was decreased by 2.54% and 1.99%,respectively; the crude fat was increased by 64.29% and 43.75%, respectively; the calcium content was increased by 28.00% and 33.33%, respectively; the phosphorus content was increased by 9.68% and 22.73%, respectively; the total content of amino acid was increased by 43.23% and 68.41%, respectively; the anthocyanin content of leaf was increased by 400.00% and 216.90%, respectively(P 0.05).[Conclusion] P. purpureum Schumach cv. Purple is a new high-quality forage variety with wide adaptability, high yield, rich nutrient and good palatability, which is appropriate for comprehensive exploitation and application in the southern region of China.展开更多
The Baishitouopan amaznito and topazbearing granite is one of the typical high-rubidium andhigh-fluorine granites in the eastern paft of the Mid-Tianshan belt. This intrusion is in sharp contactwith Mid-Proterozoic sc...The Baishitouopan amaznito and topazbearing granite is one of the typical high-rubidium andhigh-fluorine granites in the eastern paft of the Mid-Tianshan belt. This intrusion is in sharp contactwith Mid-Proterozoic schists, gneisses and marbles, and is compond of four zones transihonal fromthe bottom upwards: leucogranite, amazonite granite, topaz-bearing amazonite granite and topazquartz albitite.The Baishitouquan granite contains highly ordered K-feldspar, Li-rich mica, Mn-rich gamet,a-quartz and low-temerature rircon and is chemically high in Si, K, Na, Al, Li, Rb, Cs and F,and low in Ti, Fe, Ch, Mg, P, Ch, Ni, Cr, V, Sr and Ba, with Na2O>K2O. Amazonite fromthe amazonite granite zone contains 1867 ppm Rb. The F contents of bulk rocks are 3040 and4597 for the amazonite granite and topazbearing amazonite granite zones, respectivel. These twozones have δ18O values of 8.97 - 9.85%, (SMOW) and show flat REE distribution patterns withstrong Eu depletion. KAr and Rb-Sr ages of this intrusion are 226. 6 Ma and 209. 6 Marespectively, with an initial 87Sr/86Sr ratio of 0.987±0.213.The Baishitouquan granite is the product of crystallization of a lowtemperature, and wther,rubidium. and fluorine-rich magma , which may have been derived from partial melting ofmuscoviterich crustal rocks. Consolidation of this granite involved two contrasting and successivestagst melt crystallization and hydrothermal metasomasm and pforitation. Various geological features of this granite were formed during the transition from the magmatic to the hydrothermal stage.展开更多
Gold,iron,copper,lead-zinc and other mineral exploration in West Tianshan,Xinjiang Uygur Autonomous Region,has made remarkable progress in recent years.However,due to the dispute on the tectonic division of West Tians...Gold,iron,copper,lead-zinc and other mineral exploration in West Tianshan,Xinjiang Uygur Autonomous Region,has made remarkable progress in recent years.However,due to the dispute on the tectonic division of West Tianshan,the ore-controlling factors and the regional metallogenic laws are controversial.The authors analyze regional gravity data and notice that the high-value region corresponds to the Yili ancient continent,thus the southeastern boundary of the Yili ancient continent is delineated.Comparative analysis of gravity,aeromagnetic and geologic data reveals that the Tulasu basin,where some medium to large epithermal gold deposits locate,lies above the Yili ancient continent;the Yili Carboniferous-Permian rift extends in E-W direction,numbers of copper deposits have been found in the mid-west section of the rift which lies above the Yili ancient continent,whereas few copper deposits have been discovered in the east section which is outside the Yili ancient continent.Accordingly,the Yili ancient continent may be rich in gold,copper and other metal elements;the metal-bearing hydrothermal solution moves up with the activity of magmatism,and deposits in the favorable places(the Tulasu basin and the Yili Carboniferous-Permian rift),forming numerous small and medium gold,copper deposits,as well as some large and super-large gold deposits.Therefore,the tectonic-magmatic hydrothermal zone above the Yili ancient continent should be the prospective area for epithermal gold and copper polymetallic deposits.展开更多
The Yushugou terrain of high\|pressure granulite facies in southern Tianshan Mountain is composed mainly of an ophiolite suite. Most selected zircons are round or elliptical in shape, and some are of tetragonal prism ...The Yushugou terrain of high\|pressure granulite facies in southern Tianshan Mountain is composed mainly of an ophiolite suite. Most selected zircons are round or elliptical in shape, and some are of tetragonal prism with round edges. The granulometric analyses show that they are well sorted in sedimentation. ZrO\-2/HfO\-2 ratios in zircons range from 45 to 57. These characters, together with the petrologic and geochemical characters of plagioclase\|garnet\|orthopyroxenite bearing zircons, indicate that the protolith of plagioclase\|garnet\|orthopyroxenite may be derived mainly from volcanic base surge sedimentary debris in oceanic islands and from clays formed by seafloor weathering. Zircons are simply of pyroclastic debris. The ophiolite formation age of (440±18) Ma and the first\|stage metamorphic age (amphibolite or granulite facies) of (364±5) Ma were obtained with a method of multiple grains in different groups and a method of concordia plot. These ages provide important information on the temporal and spatial occurrence of southern Paleozoic Tianshan Ocean, the subduction rate of the oceanic crust and the formation mechanism of ophiolite of granulite facies.展开更多
Xinjiang is a good place, with pastureland to the north and south of the Tianshan MountainThe Gobi Desert has been changed into fertile fields, irrigated by melting snows.
Well-preserved Ginkgo pollen organs are analyzed from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, and are described as a new species, Ginkgo...Well-preserved Ginkgo pollen organs are analyzed from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, and are described as a new species, Ginkgo hamiensis Z.X. Wang et B.N. Sun sp. nov. The immature male cones are cylindrical and catkin-like, with two longitudinal stripes on the stalk. The pollen sacs are shaped like a long oval with two pollen sacs fused together for each microsporophyll, and the microsporophyll tip is a triangular cystidium. The pollen grains are oblong or fusiform and monocolpate; both ends are blunt or sharp. By comparison with previously reported fossil records of Ginkgo plants, we determined that the current fossils are different from all other reported species; thus, the present fossil is referred to as a new species of Ginkgo. The reproductive organs of the Ginkgo fossils described herein can provide valuable information for the study of Ginkgo plants. Further, there are two probable evolutionary trends in the Ginkgo pollen cones. One trend is that the number of pollen sacs changed from three or four during the Jurassic and Cretaceous to two at the present day; the other is that the number of pollen sacs has remained two from the Middle Jurassic to the present day. In addition, the pollen cones described herein are similar to the pollen cones of the extant Ginkgo, which strongly indicates that the morphology of Ginkgo plants may have remained highly conserved over millions of years.展开更多
In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The reco...In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9.展开更多
基金Supported by Bingtuan Science and Technology Program(2021DB0012021BB023)Science and Technology Innovation Team of Tarim University(TDZKCX202102).
文摘Apple disease samples were collected from the southern Xinjiang and annotated to design a convolutional neural network model based on deep learning.The accuracy and robustness of the model was improved through training and optimization algorithms,and a complete apple disease identification system was developed with the model as the core,and evaluated for its performance in terms of accuracy,recall rate and speed.This study provides a reliable AI-based apple disease diagnosis solution for the apple planting industry in the southern Xinjiang,hoping to help farmers better manage and protect crop health.
基金Supported by the Key Project of Research on Foreign Language Teaching in Universities of Xinjiang in 2022(XJGXWYJG2022A04)the First Planning Project of Research on Huang Yanpei s Vocational Education Thought in 2022(ZJS2022YB198).
文摘At present,the lack of Chinese culture in higher vocational English teaching in southern Xinjiang is serious.The existing English curriculum system is not enough to support the goal of cultivating ethnic minority college students cultural confidence,and its curriculum ideological and political construction is still in the initial stage of exploration.The combination of the Chinese national culture and the ethnic culture of Xinjiang and the ideological and political elements organically integrated into cultural confidence have endowed the vocational English education in Xinjiang with the characteristics of the times.In this paper,from the perspective of China s"cultural confidence",ideological and political elements were explored,and the background of ideological and political construction in higher vocational English teaching course in southern Xinjiang was analyzed;it is expounded that the ideological and political construction is an inevitable requirement for the high-quality development of vocational English education in southern Xinjiang,and the content design and implementation path of higher vocational English course was explored to provide new ideas and new ways for the curriculum ideological and political construction of higher vocational English teaching in southern Xinjiang.
基金supported by the National Natural Science Foundation of China(40875010,41005050)the Xinjiang Science and Technology Support Project(200891129)the Global Change National Key Scientific Research Project(2011 CB952002)
文摘Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature (SST). Most previous studies focused on the monsoon regions in East China, and only a few laid emphases on arid environments. In Xinjiang, which is located in Northwest China, the climate is typically arid and semi-arid. During the past 20 years, the pre- cipitation in Xinjiang has shown a significant increasing trend, and it is closely related to oasis irrigation. This paper aims at discussing whether abnormal soil moisture in spring can be the signal to forecast summer precipitation. The effects of abnormal soil moisture due to farm irrigation in spring in arid environments on regional climate are inves- tigated by using a regional climate model (RegCM3). The results indicate that positive soil moisture anomaly in irrigated cropland surface in May led to an increase in precipitation in spring as well as across the whole summer. The impact could last for about four months. The effects of soil moisture on the surface air temperature showed a time-lagging trend. The summer air temperature declined by a maximum amplitude of 0.8℃. The increased soil moisture could enhance evaporation and ascending motion in the low troposphere, which brought in more precipi- tation. The soil moisture affected regional weather and climate mainly by altering the surface sensible and latent heat fluxes.
基金Supported by the President Fund of Tarim University(TDZKQN201706)
文摘With the implementation of the "13^(th) Five-Year Plan" to promote the border area and raise rural living standards, the Xinjiang Production and Construction Corps has paid more and more attention to the development of protected agriculture, which is needed for the comprehensive development and stability of the border groups. In this paper, the current status of greenhouse tomato production in Aksu of southern Xinjiang is analyzed and summarized, finding the following: the structure is not reasonable with poor performance; the soilless cultivation mode is gradually developed, and there are innovative forms; the fertilization structure is not reasonable and needs improvement; the technical level is low, and it needs to be upgraded. Therefore, to solve the various problems that exist at present, some efforts are needed achieve a better production model.
文摘The tomato production facilities in southern Xinjiang have unique climatic conditions.However,due to the high salinity and degree of mineralization of the soil and the extensive management of irrigation water sources,the tomato production efficiency is low,and there is still much room for improvement.In this study,the formulas of tomato nutrient solutions were adjusted according to the local irrigation water quality characteristics,and tomato was grown in a greenhouse using sand cultivation.To select a nutrient solution formula suitable for the tomato cultivated in the local facilities,various parameters of tomato treated with different formulas were compared.The results showed the following:①Adjusting the nutrient solution formula could effectively improve the vegetative and reproductive growth indexes of tomato.②Properly decreasing the nutrient solution concentration could improve the growth indexes of tomato.③Decreases in Ca^(2+) and Mg^(2+) in the nutrient solution did not affect the growth and yield of tomato.The possible reason for the third result was that excessive cations in the water inhibited the absorption of Ca^(2+) and Mg^(2+) in the nutrient solution and had antagonistic effects.Therefore,a high nutrient solution concentration does not necessarily promote the growth of tomatoes.In summary,this study will improve the production conditions of protected tomato in the southern Xinjiang area by supporting tomato nutrient solution adjustments according to actual conditions in combination with reasonable irrigation systems and scientific management.
基金Supported by National Natural Sciences Foundation (71063019)
文摘In the context of Development of the West Regions, by using the annual data from 1999 to 2009 in whole China and 12 provinces of the western regions, we analyze the achievements of socio-economic development of Xinjiang Uygur Autonomous Region from 1999 to 2009 as follows: the economic aggregate has increased prominently and the growth rate is increasing ceaselessly; the primary industry, secondary industry and tertiary industry develop evenly, and the industrial structure is incessantly optimized; the quality of economic growth is promoted increasingly and the living standard of people is improved greatly; the primary industry, secondary industry and tertiary industry stride in tandem, and the momentum of growth is strong. We conduct horizontal comparison on the main economic indicators of Xinjiang, 12 provinces of the western regions and whole China, which include GDP and its growth rate, investment of fixed assets, structure of the primary industry, secondary industry and tertiary industry, the industrial added value, GDP per capita, gross retail sales of social consumption, export and import trade, net income per capita of peasants and herdsmen, and general budget revenue. The result shows that although the implementation of the strategy of Development of the West Regions and the economic development of Xinjiang have achieved some remarkable results, there is a conspicuous gap in comparison with the expected effect. The problems existing in the operation of Xinjiang's economy are analyzed as follows: the industrial level is low, and the economic growth mode is yet to be transformed; the disposable income per capita of urban residents grows slowly, and the increasing gap between the urban areas and rural areas has no trend of dwindling; the investment aggregate is very low, and the momentum of economic growth is short. In order to make the central government and 19 provinces and cities offer pointed aid for Xinjiang, promote the implementation of new strategic development of Western China, and promote the better economic development of Xinjiang in the period of the Twelfth Five-Year Plan, we put forward some feasible suggestions as follows: Xinjiang should grasp favorable opportunities and quicken the pace of industrial structural adjustment; continue to open up to the outside world unswervingly, and improve investment environment ceaselessly; strive to maintain the continuous and rapid development of economy, and improve the living standard of people.
文摘BACKGROUND^(14)C urea breath test(^(14)C UBT)and immunohistochemical staining(IHC)are widely used for detection Helicobacter pylori(H.pylori)infection with different sensitivity,and there is a difference in H.pylori infection rate in Uyghur and Han ethnic groups.Both need large cohort studies to evaluate the differences more accurately.AIM To analyze the difference between^(14)C UBT and IHC for H.pylori detection in Xinjiang Uyghur Autonomous Region and the difference between Uyghur and Han populations.METHODS There were 3944 cases of H.pylori infection detected by both IHC and^(14)C UBT at the same time(interval<1 wk,with sampling site including gastric antrum,selected from 5747 patients).We compared the sensitivity of^(14)C UBT and IHC.We also compared 555 pairs of Han/Uyghur cases(completely matched for gender and age)for their H.pylori infection rates.The overall H.pylori infection rate of all 5747 cases and the correlation with other clinicopathological data were also further analyzed.SPSS V23.0 software was used for statistical analysis.RESULTS The sensitivity was 94.9%for^(14)C UBT and 65.1%for IHC,which was a significant difference(n=3944,P<0.001).However,among those cases negative for H.pylori by^(14)C UBT(detection value≤100),4.8%were positive by IHC.Combining both methods,the overall H.pylori infection rate was 48.6%(n=5747),and differences in gender,age group,ethnicity and region of residence significantly affected the H.pylori positive rates.According to age group(Han/Uyghur),the positive rates were≤30 years(62.2%/100.0%),31-40 years(45.2%/85.7%),41-50 years(47.2%/79.2%),51-60 years(44.6%/76.1%),61-70 years(40.9%/68.2%),71-80 years(41.7%/54.1%)and≥81 years(42.9%/NA).The H.pylori infection rates of Han/Uyghur paired cases were 41.4%and 73.3%,which was a significant difference(P<0.001)(555 pairs).H.pylori positivity was significantly related to moderate-severe grade 2-3 chronic/active gastritis and intestinal metaplasia(all P<0.05).CONCLUSION The sensitivity of^(14)C UBT was significantly higher,but combined application can still increase the accuracy.The prevention H.pylori should be emphasized for Uygur and young people.
基金the National Key Basic Science Research project of China in Xinjiang the Anhui Provincial National Science Foundation for Distinguished Young Scholars (Grant No. 04045063).
文摘Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka'erjiao intrusion is mainly composed of albite granite porphyry, K-feldspar granite porphyry, ivernlte and granite porphyry. Being a transitional product between magma intrusion and eruption in the Sawur region, the Ka'erjiao intrusion was formed at the telophase of the late Carboniferous to the begining of early Permian as determined by the SHRIMP U-Pb zircon dating, with an age of 302.6±7.6 Ma (1 σ). The intrusion consists of alkali-enriched rock, whose REE distribution patterns are of the LREE enrichment type, the δEu value is low and Nd, St, Pb isotopes reflect its mantle source characteristics. The δ^18O value of intrusion is low as a result of isotope exchange with meteoric water. The geochemical characteristics show that it was formed in a post-collisional tectonic setting. Taking combined considerations of current studies of A-type granites and Permian volcanic rocks, we think that in the telophase of the late Carboniferous to the beginning of the early Permian, the Sawur region was within the extension or compressional to extensional period of a post-collisionai stage. The Ka'erjiao intrusion from mantle sources can confirm the vertical continental crust growth in the late Paleozoic. The Sawur region in west Junggar is consistent with east Junggar in post-collisionai tectonic evolution process.
基金financially supported by the China Postdoctoral Science Foundation(grant 2017M610960)China Geological Survey(grants No.DD20160346 and DD20160055)
文摘Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'an area of Shaanxi Province was firstly discovered. This deposit is currently in a detailed investigation stage, and no detailed study has been yet conducted. This work selected one molybdenite sample from the Be (W) ores in this deposit for Re-Os isotope measurements to define the time limit of tungsten and beryllium mineralization, and to further reveal the ore-forming geological setting of rare metals in the southern Qinling region.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05000000)National Natural Science Foundation of China(No.41271518)Sci-technology Project of Shaanxi Province(No.2013kw19-01)
文摘Grassland is a major carbon sink in the terrestrial ecosystem. The dynamics of grassland carbon stock profoundly influence the global carbon cycle. In the published literatures so far, however, there are limited studies on the long-term dynamics and influential factors of grassland carbon stock, including soil organic carbon. In this study, spatial-temporal substitution method was applied to explore the characteristics of Medicago sativa L. (alfalfa) grassland biomass carbon and soil organic carbon density (SOCD) in a loess hilly region with different growing years and management patterns. The results demonstrated that alfalfa was the mono-dominant community during the cutting period (viz. 0-10 year). Community succession began after the abandonment of alfalfa grassland and then the important value of alfalfa in the community declined. The artificial alfalfa community abandoned for 30 years was replaced by the S. bungeana community. Accordingly, the biomass carbon density of the clipped alfalfa showed a significant increase over the time during 0-10 year. During 0-30 year, the SOCD from 0-100 cm of the soil layer of all 5 management patterns increased over time with a range between 5.300 ± 0.981 kg/m2 and 12.578 ± 0.863 kg/m2. The sloping croplands had the lowest SOCD at 5.300 ± 0.981 kg/m2 which was quite different from the abandoned grasslands growing for 30 years which exhibited the highest SOCD with 12.578 ± 0.863 kg/m2. The ecosystem carbon density of the grassland clipped for 2 years increased 0.1 kg/m2 compared with the sloping cropland, while that of the grassland clipped for 10 years substantially increased to 10.30 ± 1.26 kg/m2. Moreover, the ecosystem carbon density for abandoned grassland became 12.62± 0.50 kg/m2 at 30 years. The carbon density of the grassland undisturbed for l0 years was similar to that of the sloping cropland and the grassland clipped for 2 years. Different management patterns imposed great different effects on the accumulation of biomass carbon on artificial grasslands, whereas the ecosystem carbon density of the grassland showed a slight increase from the clipping to abandonment of grassland in general.
文摘ccording to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)].τ0 values for intermediate and small earthquakes occurred in Chinese mainland and Southern California have been calculated by use of these equations. The results demonstrate that the level and distribution of τ0 are closely related to the location where large earthquakes will occur, i.e. the region with higher level of τ0 will be prone to occur large earthquakes and the region with lower level will usually occur small earthquakes. According to the spatial distribution of τ0 , the seismic hazard regions or the potential earthquake source regions can in some degree be determined. According to the variation of τ0 with time, the large earthquake occurrence time can be roughly estimated. According to the distribution of τ0 in Southern California and variation with time, three high stress level regions are determined, one (Goldfield area) of them is the present seismic hazard region.
基金Supported by National Natural Science Foundation of China(41271159)Engagement Fund of Xi'an University of Science and Technology(201103)+1 种基金Doctor Startup Fund of Xi'an University of Science and Technology(2011QDJ036)College Students' Innovation and Entrepreneurship Training Program of XUST(S13018)
文摘To study the dynamic changes of land use and predict the future land use scenarios based on the current land use,this paper uses Cellular Automata- Markov( CA- Markov) model to simulate the landscape pattern in 2030. The results show that in the study area during the period 1980- 2005,grassland and construction land increased,and woodland increased slightly; waters and unused land decreased,and arable land underwent dramatic changes. The simulation precision of CA- Markov model is 87. 28%,indicating that the use of it for simulation is reliable. The land use of the study area will be changed greatly in the future. This method provides a reference for the regions to carry out land prediction,and the research results can provide a basis for the study of optimization of land.
文摘This study presents the changes in lake areas in the Valley of Lakes, the Govi region, southern Mongolia. The recent changes in lake areas show decreases depending on vulnerability of lake basins and response of Govi landscape to the present climatic warming. During the recent 44 - 45 years (from 1970 to 2014 or 2015), modern lakes have encountered the present rapid increase in temperature, water evaporation and drying up that induced the reduction in lake areas in the Valley of Lakes. The finding of the reduction in lake areas is consistent with the trends on increasing in temperature since 1995 and fluctuating precipitation since 1975. Investigations with detailed chronology of lake sediment are needed from the lakes to review a more complete evolution of lake basins during the Late Quaternary paleoclimatic history in Mongolia and Central Asia.
基金Supported by the Planning Project of the Twelfth Five-Year-Plan in National Science and Technology for the Rural Development in China(2011BAD17B03)the Science and Technology Planning Project of the Department of Aquatic Products,Animal Husbandry and Veterinary Services of Guangxi Province(GUIYUMUKE201452006,201453057,201452043,1304558)~~
文摘[Objective] The present experiment was conducted to investigate the yield,adaptability and quality characteristics of Pennisetum purpureum Schumach cv. Purple to provide reference for the certification and development of new varieties.[Method] With P. purpureum Schumab cv. Purple as experimental material, the variety comparison tests were conducted in Nanning, Lingyun, and Tiandeng in Guangxi from 2007 to 2009, and variety regional trials were conducted in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Its comprehensive characters of plant height, hay yield, stem-leaf ratio and nutritional components were determined, and were compared with those of P. purpureum × P.americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin. [Result] The average height of P. purpureum Schumach cv. Purple was 706.54 cm, which was5.92% and 8.44% lower than that of P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin, respectively. The average hay yield of P. purpureum Schumach cv. Purple was 32.74 t/ha in Nanning, Lingyun, and Tiandeng of Guangxi from 2007 to 2009, and 22.41 t/ha in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Although its hay yield was lower than two control varieties, the difference was not significant(P 0.05).The stem-leaf ratio of P. purpureum Schumach cv. Purple was 0.98:1. Moreover,the analysis on the nutritional components of dry matter showed that compared with P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv.Guiminvin, the crude fiber of P. purpureum Schumab cv. Purple was decreased by4.76% and 2.78%, respectively; the neutral detergent fiber decreased by 5.07% and2.22%, respectively; the acid detergent fiber was decreased by 2.54% and 1.99%,respectively; the crude fat was increased by 64.29% and 43.75%, respectively; the calcium content was increased by 28.00% and 33.33%, respectively; the phosphorus content was increased by 9.68% and 22.73%, respectively; the total content of amino acid was increased by 43.23% and 68.41%, respectively; the anthocyanin content of leaf was increased by 400.00% and 216.90%, respectively(P 0.05).[Conclusion] P. purpureum Schumach cv. Purple is a new high-quality forage variety with wide adaptability, high yield, rich nutrient and good palatability, which is appropriate for comprehensive exploitation and application in the southern region of China.
文摘The Baishitouopan amaznito and topazbearing granite is one of the typical high-rubidium andhigh-fluorine granites in the eastern paft of the Mid-Tianshan belt. This intrusion is in sharp contactwith Mid-Proterozoic schists, gneisses and marbles, and is compond of four zones transihonal fromthe bottom upwards: leucogranite, amazonite granite, topaz-bearing amazonite granite and topazquartz albitite.The Baishitouquan granite contains highly ordered K-feldspar, Li-rich mica, Mn-rich gamet,a-quartz and low-temerature rircon and is chemically high in Si, K, Na, Al, Li, Rb, Cs and F,and low in Ti, Fe, Ch, Mg, P, Ch, Ni, Cr, V, Sr and Ba, with Na2O>K2O. Amazonite fromthe amazonite granite zone contains 1867 ppm Rb. The F contents of bulk rocks are 3040 and4597 for the amazonite granite and topazbearing amazonite granite zones, respectivel. These twozones have δ18O values of 8.97 - 9.85%, (SMOW) and show flat REE distribution patterns withstrong Eu depletion. KAr and Rb-Sr ages of this intrusion are 226. 6 Ma and 209. 6 Marespectively, with an initial 87Sr/86Sr ratio of 0.987±0.213.The Baishitouquan granite is the product of crystallization of a lowtemperature, and wther,rubidium. and fluorine-rich magma , which may have been derived from partial melting ofmuscoviterich crustal rocks. Consolidation of this granite involved two contrasting and successivestagst melt crystallization and hydrothermal metasomasm and pforitation. Various geological features of this granite were formed during the transition from the magmatic to the hydrothermal stage.
基金This research is financially supported by China Geological Survey project“Comprehensive Monitoring of Resources and Environment Bearing Capacity and Digital Platform Construction of Xiongan New Area”(121201003000172401)“Aero Geophysical Survey of Qinling and Tianshan metallogenetic belt”(121201003000150006).
文摘Gold,iron,copper,lead-zinc and other mineral exploration in West Tianshan,Xinjiang Uygur Autonomous Region,has made remarkable progress in recent years.However,due to the dispute on the tectonic division of West Tianshan,the ore-controlling factors and the regional metallogenic laws are controversial.The authors analyze regional gravity data and notice that the high-value region corresponds to the Yili ancient continent,thus the southeastern boundary of the Yili ancient continent is delineated.Comparative analysis of gravity,aeromagnetic and geologic data reveals that the Tulasu basin,where some medium to large epithermal gold deposits locate,lies above the Yili ancient continent;the Yili Carboniferous-Permian rift extends in E-W direction,numbers of copper deposits have been found in the mid-west section of the rift which lies above the Yili ancient continent,whereas few copper deposits have been discovered in the east section which is outside the Yili ancient continent.Accordingly,the Yili ancient continent may be rich in gold,copper and other metal elements;the metal-bearing hydrothermal solution moves up with the activity of magmatism,and deposits in the favorable places(the Tulasu basin and the Yili Carboniferous-Permian rift),forming numerous small and medium gold,copper deposits,as well as some large and super-large gold deposits.Therefore,the tectonic-magmatic hydrothermal zone above the Yili ancient continent should be the prospective area for epithermal gold and copper polymetallic deposits.
文摘The Yushugou terrain of high\|pressure granulite facies in southern Tianshan Mountain is composed mainly of an ophiolite suite. Most selected zircons are round or elliptical in shape, and some are of tetragonal prism with round edges. The granulometric analyses show that they are well sorted in sedimentation. ZrO\-2/HfO\-2 ratios in zircons range from 45 to 57. These characters, together with the petrologic and geochemical characters of plagioclase\|garnet\|orthopyroxenite bearing zircons, indicate that the protolith of plagioclase\|garnet\|orthopyroxenite may be derived mainly from volcanic base surge sedimentary debris in oceanic islands and from clays formed by seafloor weathering. Zircons are simply of pyroclastic debris. The ophiolite formation age of (440±18) Ma and the first\|stage metamorphic age (amphibolite or granulite facies) of (364±5) Ma were obtained with a method of multiple grains in different groups and a method of concordia plot. These ages provide important information on the temporal and spatial occurrence of southern Paleozoic Tianshan Ocean, the subduction rate of the oceanic crust and the formation mechanism of ophiolite of granulite facies.
文摘Xinjiang is a good place, with pastureland to the north and south of the Tianshan MountainThe Gobi Desert has been changed into fertile fields, irrigated by melting snows.
基金conducted under the National Natural Science Foundation of China (No.41172022)the Funds of Key Laboratory of Petroleum Resources,Gansu Province (No.SZD-KFJJ20150603)the Fundamental Research Funds for the Central Universities (No.lzujbky-2016-202)
文摘Well-preserved Ginkgo pollen organs are analyzed from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, and are described as a new species, Ginkgo hamiensis Z.X. Wang et B.N. Sun sp. nov. The immature male cones are cylindrical and catkin-like, with two longitudinal stripes on the stalk. The pollen sacs are shaped like a long oval with two pollen sacs fused together for each microsporophyll, and the microsporophyll tip is a triangular cystidium. The pollen grains are oblong or fusiform and monocolpate; both ends are blunt or sharp. By comparison with previously reported fossil records of Ginkgo plants, we determined that the current fossils are different from all other reported species; thus, the present fossil is referred to as a new species of Ginkgo. The reproductive organs of the Ginkgo fossils described herein can provide valuable information for the study of Ginkgo plants. Further, there are two probable evolutionary trends in the Ginkgo pollen cones. One trend is that the number of pollen sacs changed from three or four during the Jurassic and Cretaceous to two at the present day; the other is that the number of pollen sacs has remained two from the Middle Jurassic to the present day. In addition, the pollen cones described herein are similar to the pollen cones of the extant Ginkgo, which strongly indicates that the morphology of Ginkgo plants may have remained highly conserved over millions of years.
基金National Natural Science Foundation of China (49974012) and Joint Seismological Science Foundation of China (604004).
文摘In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9.