A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new...A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new compound was identified by spectrum analysis.展开更多
To overcome the issues of high cost and continuous cropping obstacles in facility cultivation of Panax notoginseng_ F. H. Chen, satisfy the market demand, save the production cost, improve the utilization rate of fore...To overcome the issues of high cost and continuous cropping obstacles in facility cultivation of Panax notoginseng_ F. H. Chen, satisfy the market demand, save the production cost, improve the utilization rate of forest land, increase the in-come of forest farmers and protect the ecological environment, the cultivation tech-niques of high-quality P. notoginseng seedlings from Wenshan, Yunnan under four kinds of forests (walnut forest, China fir forest, grape forest and kiwi forest) were in-vestigated in this study. The results showed that the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng_under walnut forest were higher than those under the other three kinds of forests; the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng under China fir forest were higher than those under grape forest and kiwi forest; and the crown di-ameter and survival rate under grape forest were higher, and the height growth and tuber weight under grape forest were lower than those under kiwi forest. Walnut is a broad-leaved deciduous tree species, so large-scale cultivation of P. notoginseng_should be conducted under broadleaf deciduous forest with canopy density around 0.8, taking advantage of the cool environment and rich humus layer under forest. This cultivation technology could save labor, shade, fertilizer and other costs, and accord with the ecological habit and the growth rules of P. notoginseng, thus im-proving yield and achieving high economic benefit.展开更多
Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah ...Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah (Silkworm) pupa were carried out by 搕hree-cut method?and inoculating method. The results showed that three-cut method is effective way for breed-ing Chouioia cunea, with a parasitical rate of 95%. The biological characteristics and the life cycle of Chouioia cunea were ob-served and described and more hosts of Chouioia cunea were found. 揟hree-cut method?as a new technique of rearing Chouioia cunea has been put into practice.展开更多
[Objective] The study was to solve the contradiction between fungus and forest during the production of black fungi, and to obtain relatively high economic benefits and ecological benefits. [Method] Black fungi were c...[Objective] The study was to solve the contradiction between fungus and forest during the production of black fungi, and to obtain relatively high economic benefits and ecological benefits. [Method] Black fungi were cultivated in forest with middle-high altitude of 500-1 600 m. The germination time of fungus stick, germination days of buds, growth days of fruiting body, commodity exterior, marketing effect and biological efficiency of black fungi were investigated. [Result] Compared with traditional cultivation, black fungus products cultivated under forest had the taste and flavor of wild black fungus. Fungus chaff wastage was directly decomposed by the roots in forest land, improving the soil structure of forest land. The need of moisture retention and the frequent access of administrative staff reduced the probability of forest fire occurrence. [Conclusion] Cultivation of black fungus under forest saves more than 70% fixed-asset investment on fungus shed, and the biological efficiency reached 12.2%.展开更多
Surface-enhanced Raman scattering(SERS)is a powerful technology for obtaining vibrational information from molecules that present in different chemical or biological environments.This paper presents a 3D SERS substrat...Surface-enhanced Raman scattering(SERS)is a powerful technology for obtaining vibrational information from molecules that present in different chemical or biological environments.This paper presents a 3D SERS substrate based on nanocone forests.The substrates are prepared by using plasma treatment technique,which is a simple,fast and high-throughput approach.The SERS substrate based on nanocone forests exhibits high sensitivity.In the experiment,miRNA with a concentration as low as 10-10 M can be achieved.Meanwhile,the proposed SERS substrate shows a high uniformity over a large area.These experimental results demonstrate great potential of the 3D SERS substrate in wide applications.展开更多
Three-North Shelterbelt Forest (TSF) program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region ...Three-North Shelterbelt Forest (TSF) program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region is important for understanding the overall function of carbon sequestration of the forest and other terrestrial ecosystems in China. This study investigated the distribution area of shrubland in the TSF region based on remote sensing images in 1978 and 2008, and calculated the carbon density of shrubland in combination with the field investigation and previous data from published papers. The carbon sequestration quantity and rate from 1978 to 2008 was analyzed for four sub-regions and different types of shrubs in the TSF region. The results revealed that: 1) The area of shrubland in the study area and its four sub-regions increased during the past thirty years. The area of shrubland for the whole region in 2008 was 1.2 × 10^7 ha, 72.8% larger than that in 1978. The Inner Mongolia-Xinjiang Sub-region was the largest shrubland distribution area, while the highest coverage rate was found in the North China Sub-region. 2) In decreasing order of their carbon sequestration, the four types of shrubs considered in this study were Hippophae rhamnoides, Caragana spp., Haloxylon ammodendron and Vitex negundo vat. heterophylla. The carbon sequestration of/-/, rhamnoides, with a maximum mean carbon density of 16.5 Mg C/ha, was significantly higher than that of the other three species. 3) The total carbon sequestration of shrubland in the study region was 4.5 x 107 Mg C with a mean annual carbon sequestration of 1.5× 10^6 Mg C. The carbon density in the four sub-regions decreased in the following order: the Loess Plateau Sub-region, the North China Sub-region, the Northeast China Sub-region and the Inner Mongolia-Xinjiang Sub-region. The paucity of studies and data availability on the large-scale carbon sequestration of shrub species suggests this study provides a baseline reference for future research in this area.展开更多
In this letter, discrete complex image method is employed to compute the Green's functions in the spatial domain, which improves the speed of evaluating the impedance matrix.The triangle vector basis function--RWG...In this letter, discrete complex image method is employed to compute the Green's functions in the spatial domain, which improves the speed of evaluating the impedance matrix.The triangle vector basis function--RWG, is used to simulate the current distribution in order to compute the scattering properties of arbitrary shape microstrip patch without the staircase approximation. The numerical result shows the validity of the proposed method.展开更多
Prandtl’s lifting line theory was generalized to the lifting problem of a three-dimensional hydrofoil in the presence of a free surface. Similar to the classical lifting theory, the singularity distribution method wa...Prandtl’s lifting line theory was generalized to the lifting problem of a three-dimensional hydrofoil in the presence of a free surface. Similar to the classical lifting theory, the singularity distribution method was utilized to solve two-dimensional lifting problems for the hydrofoil beneath the free surface at the air-water interface, and a lifting line theory was developed to correct three-dimensional effects of the hydrofoil with a large aspect ratio. Differing from the classical lifting theory, the main focus was on finding the three-dimensional Green function of the free surface induced by the steady motion of a system of horseshoe vortices under the free surface. Finally, numerical examples were given to show the relationship between the lift coefficient and submergence Froude numbers for 2-D and 3-D hydrofoils. If the submergence Froude number is small free surface effect will be significant registered as the increase of lift coefficient. The validity of these approaches was examined in comparison with the results calculated by other methods.展开更多
The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. ...The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.展开更多
Zircon LA-ICP-MS U-Pb geochronology and geochemical analyses are undertaken for the garnet-bear-ing muscovite monzogranite in Yitong area, central Jilin Province. The formation age and petrogenesis of the granite are ...Zircon LA-ICP-MS U-Pb geochronology and geochemical analyses are undertaken for the garnet-bear-ing muscovite monzogranite in Yitong area, central Jilin Province. The formation age and petrogenesis of the granite are determined, and the regional tectonic background is discussed. Zircons from the granite are euhe-dral-subhedral in shape, and display fine-scale oscillatory growth zoning, indicating a magmatie origin. LA- ICP-MS zircon U-Pb dating result indicates that the garnet-bearing muscovite monzogranites formed in the mid-dle Triassic (243 Ma ). The garnet-bearing muscovite monzogranites have high SiO2 (SiO2 = 74.1%- 76.49% ), rich aluminum (A1203 = 14.47%-14.68% ) and alkali ( NazO + K20 = 4.31%-7.9% ), low Fe203T and MgO (MgO =0.1%-0. 13% , Fe203T =0.46%-1.02% ). The ratio of CaO/Na20 is between 0.17--0. 21. The garnet-bearing muscovite monzogranites in Yitong region are relatively enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) , and depleted of heavy rare earth elements (HREEs) and high field strength elements (HFSEs). They are characterized by high Sr and Ba, poor Rb and Y, and negative Eu abnormally (δEu =0.48-0.62) , with Rb/Sr 〈 1. The εHf(t) values and TDM2 of zircons range from + 6. 10 to + 8.00 and from 725 Ma to 814 Ma, respectively. The above features indicate that gar- net-bearing muscovite monzogranites in Yitong area were derived from partial melting of metasedimentary rock. These granites have high Sr/Y ratios, which suggest they formed in a thickened continental crust. Combined with the coeval granitic rocks in central Jilin Province, we suggested that a significant eollisional and thickening event took place during the Middle Triassic.展开更多
This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Del...This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Delta State. The specific objectives are to ascertain the socio- economic characteristics of the women, find out the forest based activities of the women, identify what they do with products collected from the forest, establish how much income they make from such products weekly and identify the challenges of these women in exploiting forest for survival. Ten villages were selected and from the selected communities, 15 women were randomly selected in each community to give 150 respondents. From the result of the survey about 96.0% of the respondents had household sizes of between 6-10 persons. Women collect many forest products which include seeds, herbs, honey, mushroom, fuel wood, snails, stimulants, bitter kola, pear, raffia leaves (fronds), edible worms, wrapping leaves, spices, bush mango, locust beans, wild fruits, leaves, fuel wood, snails, mushrooms and fruits. Some of the forest products are used for income generation only, some for household use, while others are used for both income generation and household use. The major constraint is the decline in the availability of forest products as a result of deforestation, over exploitation, bush burning and long distance to available forests. The study shows that forest products play a significant role in improving the livelihood of rural people. Rural development and future forest conservation strategies and interventions should pay attention to the contribution of forest products to people's livelihood and environmental sustainability.展开更多
Water shortage is an important constraint factor in the construction of the Three-North Shelterbelt (TNS). Here, we analyzed temporal-spatial patterns in water resources and trends in the Three-North region. We eval...Water shortage is an important constraint factor in the construction of the Three-North Shelterbelt (TNS). Here, we analyzed temporal-spatial patterns in water resources and trends in the Three-North region. We evaluated the water resource carrying capacity (WRCC) of 623 counties in the project area during the fifth phase of the TNS Development Program. Results show that 387 counties are appropriate for forestation, 185 counties can be planted, and 60 counties are inappropriate for forestation because of water resource constraints.展开更多
The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has im...The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.展开更多
The Yellow River Delta (YRD) is one of the biggest deltas that have not been developed in the world. During the turn of the centuries, YRD development is listed in the two major projects in the new century by Shandong...The Yellow River Delta (YRD) is one of the biggest deltas that have not been developed in the world. During the turn of the centuries, YRD development is listed in the two major projects in the new century by Shandong provincial government. According to the plan, YRD will become an important energy, chemical and agricultural production base in 15-20 years. In view of its location and natural conditions, so far there exist a lot of environmental problems in YRD. Thus the principle of economic development coordinating with environmental protection must be implemented during YRD development. Forestation is one of the vital measures to cope with environment degradation. Therefore, strategies of forestry development and techniques of tree planting in different land use types are discussed in the paper based on site classification with specific problems involved .展开更多
In order to understand the pattern and status of plant species in the forest-meadow ecotonein Sanjiangyuan Nature Reserve, this study was undertaken through expert consultation, literaturesurvey and fieldwork in vario...In order to understand the pattern and status of plant species in the forest-meadow ecotonein Sanjiangyuan Nature Reserve, this study was undertaken through expert consultation, literaturesurvey and fieldwork in various parts of the ecotone during 2002-2004. Based on 3 important systems,i.e. threatened status, genetic loss effect and use value, the list of threatened and prioritized plants wasestablished. In this paper, the threatened coefficient was defined as the criteria of category for threatenedplants, the conservation priorities coefficient summed by threatened coefficient, genetic coefficient anduse value coefficient was defined as the criteria of prioritized plants. In addition, 10 indicators toevaluate threatened grading and conservation priorities sequence were included in the 3 importantsystems. The weights of 3 systems and 10 indicators were given through expert consultation andanalytic hierarchy process. Ten indicators were given scores based on the subcriteria, respectively, andall the scores of the 3 systems were summed up for each species, then contrasted to the criteria ofthreatened grading and conservation priorities for plant species. The status of endangerment andconservation priorities of plant species were analyzed, and the results showed that the number ofendangered species was 2, vulnerable species 37, near threatened species 140, safe species 767; the firstconcern category had 4 species, the second concern category 18, the third concern category 150 and theleast concern category 774.展开更多
The singularities and oscillatory performance of translating-pulsating source Green's function in Bessho form were analyzed. Relative numerical integration methods such as Gaussian quadrature rule, variable substitut...The singularities and oscillatory performance of translating-pulsating source Green's function in Bessho form were analyzed. Relative numerical integration methods such as Gaussian quadrature rule, variable substitution method (VSM), and steepest descent integration method (SDIM) were used to evaluate this type of Green's function. For SDIM, the complex domain was restricted only on the 0-plane. Meanwhile, the integral along the real axis was computed by use of the VSM to avoid the complication of a numerical search of the steepest descent line. Furthermore, the steepest descent line was represented by the B-spline function. Based on this representation, a new self-compatible integration method corresponding to parametric t was established. The numerical method was validated through comparison with other existing results, and was shown to be efficient and reliable in the calculation of the velocity potentials for the 3D seakeeping and hydrodynamic performance of floating struc- tures moving in waves.展开更多
基金This work was supported by the Kunming Institute of Botany,Chinese Academy of Sciences.
文摘A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new compound was identified by spectrum analysis.
基金Supported by Central Financial Forestry Science and Technology Extension Project of China([2016]XT001)Science and Technology Development Project of Hunan Province(S2014F209021)~~
文摘To overcome the issues of high cost and continuous cropping obstacles in facility cultivation of Panax notoginseng_ F. H. Chen, satisfy the market demand, save the production cost, improve the utilization rate of forest land, increase the in-come of forest farmers and protect the ecological environment, the cultivation tech-niques of high-quality P. notoginseng seedlings from Wenshan, Yunnan under four kinds of forests (walnut forest, China fir forest, grape forest and kiwi forest) were in-vestigated in this study. The results showed that the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng_under walnut forest were higher than those under the other three kinds of forests; the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng under China fir forest were higher than those under grape forest and kiwi forest; and the crown di-ameter and survival rate under grape forest were higher, and the height growth and tuber weight under grape forest were lower than those under kiwi forest. Walnut is a broad-leaved deciduous tree species, so large-scale cultivation of P. notoginseng_should be conducted under broadleaf deciduous forest with canopy density around 0.8, taking advantage of the cool environment and rich humus layer under forest. This cultivation technology could save labor, shade, fertilizer and other costs, and accord with the ecological habit and the growth rules of P. notoginseng, thus im-proving yield and achieving high economic benefit.
文摘Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah (Silkworm) pupa were carried out by 搕hree-cut method?and inoculating method. The results showed that three-cut method is effective way for breed-ing Chouioia cunea, with a parasitical rate of 95%. The biological characteristics and the life cycle of Chouioia cunea were ob-served and described and more hosts of Chouioia cunea were found. 揟hree-cut method?as a new technique of rearing Chouioia cunea has been put into practice.
基金Supported by the Research Fund for the Youth of the Shandong Academy of Agricultural Sciences(2016YQN38)the Independent Innovation Projects for the Universities Institutes of Jinan(201303056)~~
文摘[Objective] The study was to solve the contradiction between fungus and forest during the production of black fungi, and to obtain relatively high economic benefits and ecological benefits. [Method] Black fungi were cultivated in forest with middle-high altitude of 500-1 600 m. The germination time of fungus stick, germination days of buds, growth days of fruiting body, commodity exterior, marketing effect and biological efficiency of black fungi were investigated. [Result] Compared with traditional cultivation, black fungus products cultivated under forest had the taste and flavor of wild black fungus. Fungus chaff wastage was directly decomposed by the roots in forest land, improving the soil structure of forest land. The need of moisture retention and the frequent access of administrative staff reduced the probability of forest fire occurrence. [Conclusion] Cultivation of black fungus under forest saves more than 70% fixed-asset investment on fungus shed, and the biological efficiency reached 12.2%.
文摘Surface-enhanced Raman scattering(SERS)is a powerful technology for obtaining vibrational information from molecules that present in different chemical or biological environments.This paper presents a 3D SERS substrate based on nanocone forests.The substrates are prepared by using plasma treatment technique,which is a simple,fast and high-throughput approach.The SERS substrate based on nanocone forests exhibits high sensitivity.In the experiment,miRNA with a concentration as low as 10-10 M can be achieved.Meanwhile,the proposed SERS substrate shows a high uniformity over a large area.These experimental results demonstrate great potential of the 3D SERS substrate in wide applications.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060400)
文摘Three-North Shelterbelt Forest (TSF) program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region is important for understanding the overall function of carbon sequestration of the forest and other terrestrial ecosystems in China. This study investigated the distribution area of shrubland in the TSF region based on remote sensing images in 1978 and 2008, and calculated the carbon density of shrubland in combination with the field investigation and previous data from published papers. The carbon sequestration quantity and rate from 1978 to 2008 was analyzed for four sub-regions and different types of shrubs in the TSF region. The results revealed that: 1) The area of shrubland in the study area and its four sub-regions increased during the past thirty years. The area of shrubland for the whole region in 2008 was 1.2 × 10^7 ha, 72.8% larger than that in 1978. The Inner Mongolia-Xinjiang Sub-region was the largest shrubland distribution area, while the highest coverage rate was found in the North China Sub-region. 2) In decreasing order of their carbon sequestration, the four types of shrubs considered in this study were Hippophae rhamnoides, Caragana spp., Haloxylon ammodendron and Vitex negundo vat. heterophylla. The carbon sequestration of/-/, rhamnoides, with a maximum mean carbon density of 16.5 Mg C/ha, was significantly higher than that of the other three species. 3) The total carbon sequestration of shrubland in the study region was 4.5 x 107 Mg C with a mean annual carbon sequestration of 1.5× 10^6 Mg C. The carbon density in the four sub-regions decreased in the following order: the Loess Plateau Sub-region, the North China Sub-region, the Northeast China Sub-region and the Inner Mongolia-Xinjiang Sub-region. The paucity of studies and data availability on the large-scale carbon sequestration of shrub species suggests this study provides a baseline reference for future research in this area.
文摘In this letter, discrete complex image method is employed to compute the Green's functions in the spatial domain, which improves the speed of evaluating the impedance matrix.The triangle vector basis function--RWG, is used to simulate the current distribution in order to compute the scattering properties of arbitrary shape microstrip patch without the staircase approximation. The numerical result shows the validity of the proposed method.
基金Supported by the National Natural Science Foundation of China under Grant No.50921001973 Program under Grant No. 2010CB83270
文摘Prandtl’s lifting line theory was generalized to the lifting problem of a three-dimensional hydrofoil in the presence of a free surface. Similar to the classical lifting theory, the singularity distribution method was utilized to solve two-dimensional lifting problems for the hydrofoil beneath the free surface at the air-water interface, and a lifting line theory was developed to correct three-dimensional effects of the hydrofoil with a large aspect ratio. Differing from the classical lifting theory, the main focus was on finding the three-dimensional Green function of the free surface induced by the steady motion of a system of horseshoe vortices under the free surface. Finally, numerical examples were given to show the relationship between the lift coefficient and submergence Froude numbers for 2-D and 3-D hydrofoils. If the submergence Froude number is small free surface effect will be significant registered as the increase of lift coefficient. The validity of these approaches was examined in comparison with the results calculated by other methods.
文摘The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.
基金Supported by National Basic Research Program of China(No.41572043)
文摘Zircon LA-ICP-MS U-Pb geochronology and geochemical analyses are undertaken for the garnet-bear-ing muscovite monzogranite in Yitong area, central Jilin Province. The formation age and petrogenesis of the granite are determined, and the regional tectonic background is discussed. Zircons from the granite are euhe-dral-subhedral in shape, and display fine-scale oscillatory growth zoning, indicating a magmatie origin. LA- ICP-MS zircon U-Pb dating result indicates that the garnet-bearing muscovite monzogranites formed in the mid-dle Triassic (243 Ma ). The garnet-bearing muscovite monzogranites have high SiO2 (SiO2 = 74.1%- 76.49% ), rich aluminum (A1203 = 14.47%-14.68% ) and alkali ( NazO + K20 = 4.31%-7.9% ), low Fe203T and MgO (MgO =0.1%-0. 13% , Fe203T =0.46%-1.02% ). The ratio of CaO/Na20 is between 0.17--0. 21. The garnet-bearing muscovite monzogranites in Yitong region are relatively enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) , and depleted of heavy rare earth elements (HREEs) and high field strength elements (HFSEs). They are characterized by high Sr and Ba, poor Rb and Y, and negative Eu abnormally (δEu =0.48-0.62) , with Rb/Sr 〈 1. The εHf(t) values and TDM2 of zircons range from + 6. 10 to + 8.00 and from 725 Ma to 814 Ma, respectively. The above features indicate that gar- net-bearing muscovite monzogranites in Yitong area were derived from partial melting of metasedimentary rock. These granites have high Sr/Y ratios, which suggest they formed in a thickened continental crust. Combined with the coeval granitic rocks in central Jilin Province, we suggested that a significant eollisional and thickening event took place during the Middle Triassic.
文摘This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Delta State. The specific objectives are to ascertain the socio- economic characteristics of the women, find out the forest based activities of the women, identify what they do with products collected from the forest, establish how much income they make from such products weekly and identify the challenges of these women in exploiting forest for survival. Ten villages were selected and from the selected communities, 15 women were randomly selected in each community to give 150 respondents. From the result of the survey about 96.0% of the respondents had household sizes of between 6-10 persons. Women collect many forest products which include seeds, herbs, honey, mushroom, fuel wood, snails, stimulants, bitter kola, pear, raffia leaves (fronds), edible worms, wrapping leaves, spices, bush mango, locust beans, wild fruits, leaves, fuel wood, snails, mushrooms and fruits. Some of the forest products are used for income generation only, some for household use, while others are used for both income generation and household use. The major constraint is the decline in the availability of forest products as a result of deforestation, over exploitation, bush burning and long distance to available forests. The study shows that forest products play a significant role in improving the livelihood of rural people. Rural development and future forest conservation strategies and interventions should pay attention to the contribution of forest products to people's livelihood and environmental sustainability.
基金the Principal of State Science Key Project (NO. 2007FY110300)the National Natural Science Foundation Item (NO. 41101117)
文摘Water shortage is an important constraint factor in the construction of the Three-North Shelterbelt (TNS). Here, we analyzed temporal-spatial patterns in water resources and trends in the Three-North region. We evaluated the water resource carrying capacity (WRCC) of 623 counties in the project area during the fifth phase of the TNS Development Program. Results show that 387 counties are appropriate for forestation, 185 counties can be planted, and 60 counties are inappropriate for forestation because of water resource constraints.
基金National Natural Science Foundation of China(4117111640961038)
文摘The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.
基金The research is funded by State Tenth Five-year Plan of Science & Technology Project (2004BA516A13)
文摘The Yellow River Delta (YRD) is one of the biggest deltas that have not been developed in the world. During the turn of the centuries, YRD development is listed in the two major projects in the new century by Shandong provincial government. According to the plan, YRD will become an important energy, chemical and agricultural production base in 15-20 years. In view of its location and natural conditions, so far there exist a lot of environmental problems in YRD. Thus the principle of economic development coordinating with environmental protection must be implemented during YRD development. Forestation is one of the vital measures to cope with environment degradation. Therefore, strategies of forestry development and techniques of tree planting in different land use types are discussed in the paper based on site classification with specific problems involved .
基金This research is one part of "The Rapid Evaluation Technology of Threatened Species in Sanjiangyuan Nature Reserve " (2001BA510B10-03), which is supported by the National Advanced Project of the Tenth Five-year Plan.
文摘In order to understand the pattern and status of plant species in the forest-meadow ecotonein Sanjiangyuan Nature Reserve, this study was undertaken through expert consultation, literaturesurvey and fieldwork in various parts of the ecotone during 2002-2004. Based on 3 important systems,i.e. threatened status, genetic loss effect and use value, the list of threatened and prioritized plants wasestablished. In this paper, the threatened coefficient was defined as the criteria of category for threatenedplants, the conservation priorities coefficient summed by threatened coefficient, genetic coefficient anduse value coefficient was defined as the criteria of prioritized plants. In addition, 10 indicators toevaluate threatened grading and conservation priorities sequence were included in the 3 importantsystems. The weights of 3 systems and 10 indicators were given through expert consultation andanalytic hierarchy process. Ten indicators were given scores based on the subcriteria, respectively, andall the scores of the 3 systems were summed up for each species, then contrasted to the criteria ofthreatened grading and conservation priorities for plant species. The status of endangerment andconservation priorities of plant species were analyzed, and the results showed that the number ofendangered species was 2, vulnerable species 37, near threatened species 140, safe species 767; the firstconcern category had 4 species, the second concern category 18, the third concern category 150 and theleast concern category 774.
基金Project supported by the National Natural Science Foundation of China (No. 50879090), and the Key Research Program of Hydrody- namics of China (No. 9140A 14030712JB 11044)
文摘The singularities and oscillatory performance of translating-pulsating source Green's function in Bessho form were analyzed. Relative numerical integration methods such as Gaussian quadrature rule, variable substitution method (VSM), and steepest descent integration method (SDIM) were used to evaluate this type of Green's function. For SDIM, the complex domain was restricted only on the 0-plane. Meanwhile, the integral along the real axis was computed by use of the VSM to avoid the complication of a numerical search of the steepest descent line. Furthermore, the steepest descent line was represented by the B-spline function. Based on this representation, a new self-compatible integration method corresponding to parametric t was established. The numerical method was validated through comparison with other existing results, and was shown to be efficient and reliable in the calculation of the velocity potentials for the 3D seakeeping and hydrodynamic performance of floating struc- tures moving in waves.