Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the incr...Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the increase of regional developing projects has led to a sharp decrease of this ancient and rare plant in naturally distributed habitats and natural population. In this paper, the biological and ecological characteristics of Dovetree were described, and the geographically distributed condition of this species in different geologic periods as well as the major reasons for dynamic changes of its population were systematically analyzed in accordance with field researches and references. The investigations conducted in different years by setting up standard sample plots showed that the population number of Dovetree increased yearly in the areas without human interference but decreased yearly in the areas with human interference. With the increase of population density and human activities decreased as the logarithmic curve:Y=?100.7ln(x)+178.09, and it has turned from a dominant population into an endangered population. Based on the former and present studies on Dovetree, some protection strategies were put foreword for protecting this ancient and rare species. Keywords Davidia involucrate - Dovetree - Geographical Distribution - Biological Characteristics - Protection Policy CLC number S718.4 Document code A Article ID 1007-662X(2004)01-0039-06 Foundation Item: This research was coordinated by the National Natural Science Foundation of China (No. 39970591)Biography: Wu Gang (1965-), Male, Professor in Key Laboratory of Systems Ecology, Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.Responsible editor: Chai Ruihai展开更多
Changbai Mountain forest area is not only is a national timber base but also a green ecological defense for Songliao Plain of NE China. The Natural Forest Protection Project of this area has an important bearing on th...Changbai Mountain forest area is not only is a national timber base but also a green ecological defense for Songliao Plain of NE China. The Natural Forest Protection Project of this area has an important bearing on the social and economic sustainable development of Jilin Province or even the whole forest area in NE China. This paper summarized general conditions of natural forest in Changbai Mountain state-owned forest area and put forward six problems need to be urgently solved and five strategic suggestions on natural forest protection and sustainable management.展开更多
The height growth of bamboo in 2008 and 2009 as well as the water contents of bamboo stump,leaves,straw,and rhizome in 2009 were measured at the Tianmu Mountain Nature Reserve.The results revealed that the relationshi...The height growth of bamboo in 2008 and 2009 as well as the water contents of bamboo stump,leaves,straw,and rhizome in 2009 were measured at the Tianmu Mountain Nature Reserve.The results revealed that the relationship between the height growth(Pn)and growth time(t)showed S-shaped curve in the two years;the water contents of bamboo stump,leaf,straw,rhizome and bamboo shoot were 0.50-2.31,0.46-1.8,0.50-1.38,0.56-1.58 and 0.89-8.96,respectively.Among them,the water content of bamboo shoot was the highest and noticeable changed,followed by bamboo stump,leaves,rhizome and straw in order.The water contents of the underground and aboveground parts respectively were 0.34-0.62 and 0.33-0.57.展开更多
A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could ...A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could deeply plough and scarify soil with a depth up to 30-50 cm, which is deeper than the depth of tractor tillage, solving the problem of difficulties in deeply ploughing and scarifying soil and keeping soil loose for muttiple seasons. The application to 20 crops in 18 provinces proved that yield could be increased by 10%-30% without increase in chemical fertilizer, quality could be improved by more than 5%, and water storage could be increased by 100%; yield could be increased for multiple seasons sustainably, and the yield of dry-land crops increased by 32.57%-38.2% from the second year to the fourth year; the net benefits of rice increased by 21.82% averagely from the first season to the sixth season; and the usage amount of chemical fertilizer decreased by 0.35-4.29 kg per 100 kg produced grain compared with conventional tillage, with an decrease amplitude of 10.81%-30.99%. It was discussed that the Fenlong technique could maximize friendly permanently-sustainable unitization of "natural resources" including soil nutrients, water, oxygen and light energy, and has good development potential in multiple fields. It was put forward that if it is popularized in 0.67x108 hm2, pro- ductivity of farmland could be newly increased by 0.1-0.13×10^8 hm2, 5.0 ×10^6 t of chemical fertilizer could be saved, the' storage of agricultural water could be in- creased by 3.0×10^10 m3, and increased food could feed 2,0-3.0×10^8 people.展开更多
The basic theory and effect of the new farming method of "Fenlong" cultivation which has been included in the main extension technology of Ministry of Agriculture of the People's Republic of China is fully illustra...The basic theory and effect of the new farming method of "Fenlong" cultivation which has been included in the main extension technology of Ministry of Agriculture of the People's Republic of China is fully illustrated for the first time, and it is the fourth set (generation) of farming modes and methods following manpower, animal and mechanical (tractor) farming. It follows the natural law to achieve soil activation, water saving, oxygen increase, warming and desalination through the active use of natural resources like soil, rainfall and solar energy, thereby promoting a new round of natural agricultural production and quality improvement and water con- servation, which has crop yield increase by 10%-30%, quality improvement of 5%, natural precipitation retaining increase by100%. The characteristics and mechanism are the use of spiral drill for one-time completion of the land preparation by drilling vertically to 30-50 cm of soil layer through high speed peeling. After instant high temperature and many fierce impacts, mechanical frictions, it could achieve the multiplication of the number of loose soil, soil physical modification and expansion of the soil nutrients, reservoirs, oxygen, microorganisms ("Four pools"). Fenlong cultivation can give birth to new farming culture and civilization, and it can achieve the physical "desalinized" transformation and utilization of saline soil. The formation of Fenlong green farming technology system makes it possible to invent the farming tools of "serf-propelled Fenlong machinery" that has got the patent, and it is the method for farmland (dry land, paddy field) Fenlong cultivation, saline-alkali soil smash-ridging cultivation and for the abundance of grass ecology on degraded grassland. The application of Fenlong "4+1" (arable, saline-alkali soil, grasslands, Sponge City+rivers) green development in China can achieve the "double safety" of food and living space.展开更多
The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages a...The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages and outstanding effects in respect of the tobacco moisture content maintaining and cigarette suction comfort promoting.The development necessity,major types,functional mechanism and influence on cigarette quality of new natural tobacco humectants development were compared and elaborated.Additionally,the prospect of new natural tobacco humectants development and application was forecasted.展开更多
The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, ...The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, the world′s most populous nation supporting some of the most valuable biodiversity hotspots in the world. In this study, we conducted a long-term and large-scale analysis of the effectiveness of 20 of the earliest nature reserves established in Hainan Province, an island home to among the highest concentration of plants and animals in China. Remote sensing imagery from 1988, 1998, and 2008 were analyzed to investigate the temporal and spatial changes of natural forests in these nature reserves and surrounding areas. We also conducted transition matrix analysis and principle component analysis to identify the driving factors that affect the protection effectiveness of nature reserves. The results were as follows: 1) During the 20-year period from 1988 to 2008, natural forests coverage of the 20 studied nature reserves dropped 2.34 percentage points, whereas the natural forests coverage dropped 11.31 percentage points in a 0–5 km outside reserve buffer and 9.36 percentage points in a 5–10 km outside reserve buffer, indicating a significant inhibitory effect of the nature reserves on the loss of natural forests. 2) Natural forests coverage dropped in 60% of the studied nature reserves during the 20-year period, suggesting a poor protection effectiveness of these reserves, while the coverage proportion showed some increase(0%/yr–5%/yr) in other reserves. 3) Expansion of rubber and pulp forests as part of a booming economy were the main factors affecting the effectiveness of the nature reserves for conserving natural forests in Hainan Province. The results of this study provide an important empirical basis for the protection of natural forests in Hainan Province, which can be used as a blueprint for nature reserve evaluation in other places in China.展开更多
Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!fil...Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.展开更多
Based on the data from China′s Seventh Forest Inventory for the period of 2004–2008, area and stand volume of different types and age-classes of plantation were used to establish the relationship between biomass den...Based on the data from China′s Seventh Forest Inventory for the period of 2004–2008, area and stand volume of different types and age-classes of plantation were used to establish the relationship between biomass density and age of planted forests in different regions of the country. Combined with the plantation area in the first-stage of the Natural Forest Protection(NFP) program(1998–2010), this study calculated the biomass carbon storage of the afforestation in the first-stage of the program. On this basis, the carbon sequestration potential of these forests was estimated for the second stage of the program(2011–2020). Biomass carbon storage of plantation established in the first stage of the program was 33.67 Tg C, which was majority accounted by protection forests(30.26 Tg C). There was a significant difference among carbon storage in different regions, which depended on the relationship of biomass carbon density, forest age and plantation area. Under the natural growth, the carbon storage was forecasted to increase annually from 2011 to 2020, reaching 96.03 Tg C at the end of the second-stage of the program in 2020. The annual growth of the carbon storage was forecasted to be 6.24 Tg C/yr, which suggested that NFP program has a significant potential for enhancing carbon sequestration in plantation forests under its domain.展开更多
The secrecy rate of limited feedback beamforming is studied for a Multiple-Input Single-Output(MISO) wiretap channel with a multi-antenna eavesdropper.We first obtain the secrecy rate of limited feedback beamforming a...The secrecy rate of limited feedback beamforming is studied for a Multiple-Input Single-Output(MISO) wiretap channel with a multi-antenna eavesdropper.We first obtain the secrecy rate of limited feedback beamforming achieved at the legitimate receiver.We then derive a lower bound for the asymptotic secrecy rate in the large system limit.From this bound,we observe a threshold for the ratio of eavesdrop antennas to transmit antennas to obtain a positive secrecy rate.We further show that the secrecy rate loss due to limited feedback decays with the number of feedback bits per transmit antenna.展开更多
The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting a...The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage(tree, understory, forest floor and soil) in the forest region of northeastern(NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests(5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%–77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%–23.0% and 5.0%–6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage.展开更多
This paper analyzed the water-retention mechanism of feldspathic sandstone (fine-(〈 1 mm diam.) and gravel-sized (2-3 cm diam.) in Mu Us Sandy Land, Northwest China. The objective of this study is to study the e...This paper analyzed the water-retention mechanism of feldspathic sandstone (fine-(〈 1 mm diam.) and gravel-sized (2-3 cm diam.) in Mu Us Sandy Land, Northwest China. The objective of this study is to study the effect of feldspathic sandstone amendment on water retention in sandy land. The results showed that as the proportion of fine feldspathic sandstone in the sandy land soil increased, the soil texture changed from sand to silt loam, the capillary po- rosity gradually increased from 26.3% to 44.9%, and the soil saturated hydraulic conductivity decreased from 7.10 ram/rain to 0.07 mm/min. Feldspathic sandstone gravel formed micro-reservoirs in the sandy land soil, playing the role of a 'water absorbent' and 'water retaining agent' in sandy land. Amendment with feldspathic sandstone can increase water retention in the arable layer of sandy land by 67%. This study provides a theoretical basis for the amelioration of sandy land on a large scale. It can be concluded that amendment with feldspathic sandstone can improve the physical properties of sandy land soil and increase soil water retention.展开更多
To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Div...To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance.展开更多
In 1998, the Chinese Government implemented the NFPP (Natural Forest Protection Program), which included logging restrictions, protected areas, replanting, and a range of other policies aimed at safeguarding the sta...In 1998, the Chinese Government implemented the NFPP (Natural Forest Protection Program), which included logging restrictions, protected areas, replanting, and a range of other policies aimed at safeguarding the state of the country's forests and reducing the risk of erosion and flooding. A second phase of this program is currently being discussed. In this paper, contingent valuation is used to estimate the WTP (willingness to pay) for maintaining the program among the inhabitants in Heilongjiang Province in northern China. The results show that, even with fairly conservative assumptions, the aggregated WTP for maintaining the program for another five years is some 3.24 billion yuan per year. This can be compared with the current cost of the Program in the province, which is some 1.57 billion yuan per year.展开更多
The current situation about the natural forest resources protection project in Haikou Forest Farm of Kunming on the protection of forest resources, forest fire prevention, forest administration resource management, fo...The current situation about the natural forest resources protection project in Haikou Forest Farm of Kunming on the protection of forest resources, forest fire prevention, forest administration resource management, forest pests, and money management was briefed. Achievements made in the implementation of natural forest protection project in Haikou Forest Farm were analyzed, and problems existing in the project as well as corresponding countermeasures were expounded.展开更多
[Objective] This study aimed to investigate the effects of space mutation on the activities of protective enzymes in different strains of Cichorium intybus L. and provide theoretical basis for screening drought-tolera...[Objective] This study aimed to investigate the effects of space mutation on the activities of protective enzymes in different strains of Cichorium intybus L. and provide theoretical basis for screening drought-tolerant plants in southern karst area. [Method] C. intybus seeds were sent into outer space by 'Shijian No.8' seed- breeding satellite. The new strains and original variety of C. intybus L. were used as experimental materials to determine the activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and malondialdehyde (MDA) content. [Result] The results showed that MDA content in PA-82, Puna chicory and PA-43 increased gradually with the increase of water stress duration, which was enhanced by 0.575, 0.72 and 0.844 μmol/g respectively at 12 days. In addition, the activities of SOD, POD and CAT increased rapidly; at 9 days, the activities of SOD in PA-82, Puna chicory and PA-43 were enhanced by 878.9, 809.2 and 711.1 U/g, with the increas- ing range of 139.1%, 136.7% and 121.1%, respectively; the activities of POD were enhanced by 4 397, 3 754 and 2 767 U/(g ·min), with the increasing range of 265.84%, 257.65% and 204.06%, respectively; the activities of CAT were enhanced by 402.1, 277.1 and 170.9 KU/L, with the increasing range of 73.08%, 39.69% and 26.20%, respectively; subsequently, the activities of these three protective enzymes were reduced significantly; at 12 days, the activities of SOD in PA-82, Puna chicory and PA-43 were reduced to 1206.5, 1144.7 and 1108.6 U/g, respectively; the activi- ties of POD were reduced to 3 145, 2 876 and 2 753 U/(g·min) , respectively; the activities of CAT were reduced to 587.2, 698.1 and 584.1 KU/L, respectively. [Con- clusion] According to the results of comprehensive evaluation, drought resistance in three C. intybus varieties exhibited a descending order of PA-82 〉 Puna chicory 〉 PA-43.展开更多
基金The National Natural Science Foundation of China (No. 39970591)
文摘Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the increase of regional developing projects has led to a sharp decrease of this ancient and rare plant in naturally distributed habitats and natural population. In this paper, the biological and ecological characteristics of Dovetree were described, and the geographically distributed condition of this species in different geologic periods as well as the major reasons for dynamic changes of its population were systematically analyzed in accordance with field researches and references. The investigations conducted in different years by setting up standard sample plots showed that the population number of Dovetree increased yearly in the areas without human interference but decreased yearly in the areas with human interference. With the increase of population density and human activities decreased as the logarithmic curve:Y=?100.7ln(x)+178.09, and it has turned from a dominant population into an endangered population. Based on the former and present studies on Dovetree, some protection strategies were put foreword for protecting this ancient and rare species. Keywords Davidia involucrate - Dovetree - Geographical Distribution - Biological Characteristics - Protection Policy CLC number S718.4 Document code A Article ID 1007-662X(2004)01-0039-06 Foundation Item: This research was coordinated by the National Natural Science Foundation of China (No. 39970591)Biography: Wu Gang (1965-), Male, Professor in Key Laboratory of Systems Ecology, Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.Responsible editor: Chai Ruihai
文摘Changbai Mountain forest area is not only is a national timber base but also a green ecological defense for Songliao Plain of NE China. The Natural Forest Protection Project of this area has an important bearing on the social and economic sustainable development of Jilin Province or even the whole forest area in NE China. This paper summarized general conditions of natural forest in Changbai Mountain state-owned forest area and put forward six problems need to be urgently solved and five strategic suggestions on natural forest protection and sustainable management.
基金Supported by Science and Technology Department 973 Program(2005CB422207,2002CB111504,2002CB410811,2005CB422208)Science and Technology Department Data Share Platform Construction Program(2006DKA32300-08)+2 种基金Science Department National Cooperation Program(200073819)National Natural Science Fund Program(40671132)Scientific Fundamental Work Special Program(2007FY110300-8)~~
文摘The height growth of bamboo in 2008 and 2009 as well as the water contents of bamboo stump,leaves,straw,and rhizome in 2009 were measured at the Tianmu Mountain Nature Reserve.The results revealed that the relationship between the height growth(Pn)and growth time(t)showed S-shaped curve in the two years;the water contents of bamboo stump,leaf,straw,rhizome and bamboo shoot were 0.50-2.31,0.46-1.8,0.50-1.38,0.56-1.58 and 0.89-8.96,respectively.Among them,the water content of bamboo shoot was the highest and noticeable changed,followed by bamboo stump,leaves,rhizome and straw in order.The water contents of the underground and aboveground parts respectively were 0.34-0.62 and 0.33-0.57.
基金Supported by Special Fund for Basic Scientific Research of Guangxi Academy of Agricultural Sciences(2014YZ07)Scientific and Technological Transformative Project of Guangxi Academy of Agricultural Sciences(201405)CARS-12-Seedling Propagation Post~~
文摘A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could deeply plough and scarify soil with a depth up to 30-50 cm, which is deeper than the depth of tractor tillage, solving the problem of difficulties in deeply ploughing and scarifying soil and keeping soil loose for muttiple seasons. The application to 20 crops in 18 provinces proved that yield could be increased by 10%-30% without increase in chemical fertilizer, quality could be improved by more than 5%, and water storage could be increased by 100%; yield could be increased for multiple seasons sustainably, and the yield of dry-land crops increased by 32.57%-38.2% from the second year to the fourth year; the net benefits of rice increased by 21.82% averagely from the first season to the sixth season; and the usage amount of chemical fertilizer decreased by 0.35-4.29 kg per 100 kg produced grain compared with conventional tillage, with an decrease amplitude of 10.81%-30.99%. It was discussed that the Fenlong technique could maximize friendly permanently-sustainable unitization of "natural resources" including soil nutrients, water, oxygen and light energy, and has good development potential in multiple fields. It was put forward that if it is popularized in 0.67x108 hm2, pro- ductivity of farmland could be newly increased by 0.1-0.13×10^8 hm2, 5.0 ×10^6 t of chemical fertilizer could be saved, the' storage of agricultural water could be in- creased by 3.0×10^10 m3, and increased food could feed 2,0-3.0×10^8 people.
基金Supported by the National Key Technology R&D Program of China(2014BAD06B05)the Major Project of Science and Technology of Guangxi(2017AA22015)~~
文摘The basic theory and effect of the new farming method of "Fenlong" cultivation which has been included in the main extension technology of Ministry of Agriculture of the People's Republic of China is fully illustrated for the first time, and it is the fourth set (generation) of farming modes and methods following manpower, animal and mechanical (tractor) farming. It follows the natural law to achieve soil activation, water saving, oxygen increase, warming and desalination through the active use of natural resources like soil, rainfall and solar energy, thereby promoting a new round of natural agricultural production and quality improvement and water con- servation, which has crop yield increase by 10%-30%, quality improvement of 5%, natural precipitation retaining increase by100%. The characteristics and mechanism are the use of spiral drill for one-time completion of the land preparation by drilling vertically to 30-50 cm of soil layer through high speed peeling. After instant high temperature and many fierce impacts, mechanical frictions, it could achieve the multiplication of the number of loose soil, soil physical modification and expansion of the soil nutrients, reservoirs, oxygen, microorganisms ("Four pools"). Fenlong cultivation can give birth to new farming culture and civilization, and it can achieve the physical "desalinized" transformation and utilization of saline soil. The formation of Fenlong green farming technology system makes it possible to invent the farming tools of "serf-propelled Fenlong machinery" that has got the patent, and it is the method for farmland (dry land, paddy field) Fenlong cultivation, saline-alkali soil smash-ridging cultivation and for the abundance of grass ecology on degraded grassland. The application of Fenlong "4+1" (arable, saline-alkali soil, grasslands, Sponge City+rivers) green development in China can achieve the "double safety" of food and living space.
基金Supported by the Fund for the Open Project of Anhui Key Laboratory of Tobacco Chemistry (No.W2015JSKF0493 and W2015JSKF0492)the China Postdoctoral Science Foundation (No.2015T80646 and 2013M531501)the National Natural Science Foundation of China (No.31400049)
文摘The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages and outstanding effects in respect of the tobacco moisture content maintaining and cigarette suction comfort promoting.The development necessity,major types,functional mechanism and influence on cigarette quality of new natural tobacco humectants development were compared and elaborated.Additionally,the prospect of new natural tobacco humectants development and application was forecasted.
基金Under the auspices of Nationwide Remote Sensing Survey and Evaluation on Ecological Environment Change in 2000–2010(No.STSN-04-00)
文摘The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, the world′s most populous nation supporting some of the most valuable biodiversity hotspots in the world. In this study, we conducted a long-term and large-scale analysis of the effectiveness of 20 of the earliest nature reserves established in Hainan Province, an island home to among the highest concentration of plants and animals in China. Remote sensing imagery from 1988, 1998, and 2008 were analyzed to investigate the temporal and spatial changes of natural forests in these nature reserves and surrounding areas. We also conducted transition matrix analysis and principle component analysis to identify the driving factors that affect the protection effectiveness of nature reserves. The results were as follows: 1) During the 20-year period from 1988 to 2008, natural forests coverage of the 20 studied nature reserves dropped 2.34 percentage points, whereas the natural forests coverage dropped 11.31 percentage points in a 0–5 km outside reserve buffer and 9.36 percentage points in a 5–10 km outside reserve buffer, indicating a significant inhibitory effect of the nature reserves on the loss of natural forests. 2) Natural forests coverage dropped in 60% of the studied nature reserves during the 20-year period, suggesting a poor protection effectiveness of these reserves, while the coverage proportion showed some increase(0%/yr–5%/yr) in other reserves. 3) Expansion of rubber and pulp forests as part of a booming economy were the main factors affecting the effectiveness of the nature reserves for conserving natural forests in Hainan Province. The results of this study provide an important empirical basis for the protection of natural forests in Hainan Province, which can be used as a blueprint for nature reserve evaluation in other places in China.
文摘Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060200)National Key Technology Research and Development Program of China(No.2012BAD22B04)Visiting Professorship for Senior International Scientists of Chinese Academy of Sciences(No.2012T1Z0006)
文摘Based on the data from China′s Seventh Forest Inventory for the period of 2004–2008, area and stand volume of different types and age-classes of plantation were used to establish the relationship between biomass density and age of planted forests in different regions of the country. Combined with the plantation area in the first-stage of the Natural Forest Protection(NFP) program(1998–2010), this study calculated the biomass carbon storage of the afforestation in the first-stage of the program. On this basis, the carbon sequestration potential of these forests was estimated for the second stage of the program(2011–2020). Biomass carbon storage of plantation established in the first stage of the program was 33.67 Tg C, which was majority accounted by protection forests(30.26 Tg C). There was a significant difference among carbon storage in different regions, which depended on the relationship of biomass carbon density, forest age and plantation area. Under the natural growth, the carbon storage was forecasted to increase annually from 2011 to 2020, reaching 96.03 Tg C at the end of the second-stage of the program in 2020. The annual growth of the carbon storage was forecasted to be 6.24 Tg C/yr, which suggested that NFP program has a significant potential for enhancing carbon sequestration in plantation forests under its domain.
基金This work was supported in part by the National Natural Science Foundation of China under Grants No.61372099,and No.61302140
文摘The secrecy rate of limited feedback beamforming is studied for a Multiple-Input Single-Output(MISO) wiretap channel with a multi-antenna eavesdropper.We first obtain the secrecy rate of limited feedback beamforming achieved at the legitimate receiver.We then derive a lower bound for the asymptotic secrecy rate in the large system limit.From this bound,we observe a threshold for the ratio of eavesdrop antennas to transmit antennas to obtain a positive secrecy rate.We further show that the secrecy rate loss due to limited feedback decays with the number of feedback bits per transmit antenna.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060200)National Key Technology Research and Development Program of China(No.2012BAD22B04)Visiting Professorship for Senior International Scientists of Chinese Academy of Sciences(No.2012T1Z0006)
文摘The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage(tree, understory, forest floor and soil) in the forest region of northeastern(NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests(5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%–77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%–23.0% and 5.0%–6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage.
基金Under the auspices of Key Direction Program of Chinese Academy of Science(No.KZCX2-YW-Q06-03)MajorState Basic Research Development Program of China(No.2009CB421103)+1 种基金National Natural Science Foundation of China(No.41001050)Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07201004)
文摘This paper analyzed the water-retention mechanism of feldspathic sandstone (fine-(〈 1 mm diam.) and gravel-sized (2-3 cm diam.) in Mu Us Sandy Land, Northwest China. The objective of this study is to study the effect of feldspathic sandstone amendment on water retention in sandy land. The results showed that as the proportion of fine feldspathic sandstone in the sandy land soil increased, the soil texture changed from sand to silt loam, the capillary po- rosity gradually increased from 26.3% to 44.9%, and the soil saturated hydraulic conductivity decreased from 7.10 ram/rain to 0.07 mm/min. Feldspathic sandstone gravel formed micro-reservoirs in the sandy land soil, playing the role of a 'water absorbent' and 'water retaining agent' in sandy land. Amendment with feldspathic sandstone can increase water retention in the arable layer of sandy land by 67%. This study provides a theoretical basis for the amelioration of sandy land on a large scale. It can be concluded that amendment with feldspathic sandstone can improve the physical properties of sandy land soil and increase soil water retention.
文摘To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance.
文摘In 1998, the Chinese Government implemented the NFPP (Natural Forest Protection Program), which included logging restrictions, protected areas, replanting, and a range of other policies aimed at safeguarding the state of the country's forests and reducing the risk of erosion and flooding. A second phase of this program is currently being discussed. In this paper, contingent valuation is used to estimate the WTP (willingness to pay) for maintaining the program among the inhabitants in Heilongjiang Province in northern China. The results show that, even with fairly conservative assumptions, the aggregated WTP for maintaining the program for another five years is some 3.24 billion yuan per year. This can be compared with the current cost of the Program in the province, which is some 1.57 billion yuan per year.
基金Sponsored by Science and Technology Projects of Kunming(2015-1-S-00643)
文摘The current situation about the natural forest resources protection project in Haikou Forest Farm of Kunming on the protection of forest resources, forest fire prevention, forest administration resource management, forest pests, and money management was briefed. Achievements made in the implementation of natural forest protection project in Haikou Forest Farm were analyzed, and problems existing in the project as well as corresponding countermeasures were expounded.
基金Supported by Science and Technology Fund of Guizhou Province(QKHJZ[2011]2165)Key Project of Agricultural Science and Technology of Guizhou Province(QKHNYZ[2009]3083,QKHNYZ[2012]3049)Special Breeding Fund of Guizhou Province(QNYZZ[2011]036)~~
文摘[Objective] This study aimed to investigate the effects of space mutation on the activities of protective enzymes in different strains of Cichorium intybus L. and provide theoretical basis for screening drought-tolerant plants in southern karst area. [Method] C. intybus seeds were sent into outer space by 'Shijian No.8' seed- breeding satellite. The new strains and original variety of C. intybus L. were used as experimental materials to determine the activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and malondialdehyde (MDA) content. [Result] The results showed that MDA content in PA-82, Puna chicory and PA-43 increased gradually with the increase of water stress duration, which was enhanced by 0.575, 0.72 and 0.844 μmol/g respectively at 12 days. In addition, the activities of SOD, POD and CAT increased rapidly; at 9 days, the activities of SOD in PA-82, Puna chicory and PA-43 were enhanced by 878.9, 809.2 and 711.1 U/g, with the increas- ing range of 139.1%, 136.7% and 121.1%, respectively; the activities of POD were enhanced by 4 397, 3 754 and 2 767 U/(g ·min), with the increasing range of 265.84%, 257.65% and 204.06%, respectively; the activities of CAT were enhanced by 402.1, 277.1 and 170.9 KU/L, with the increasing range of 73.08%, 39.69% and 26.20%, respectively; subsequently, the activities of these three protective enzymes were reduced significantly; at 12 days, the activities of SOD in PA-82, Puna chicory and PA-43 were reduced to 1206.5, 1144.7 and 1108.6 U/g, respectively; the activi- ties of POD were reduced to 3 145, 2 876 and 2 753 U/(g·min) , respectively; the activities of CAT were reduced to 587.2, 698.1 and 584.1 KU/L, respectively. [Con- clusion] According to the results of comprehensive evaluation, drought resistance in three C. intybus varieties exhibited a descending order of PA-82 〉 Puna chicory 〉 PA-43.