Pacific oyster(Crassostrea gigas)is one of the most important mollusks cultured all around the world.Selective breeding programs of Pacific oysters in China is initiated since 2006 and developed the genetically improv...Pacific oyster(Crassostrea gigas)is one of the most important mollusks cultured all around the world.Selective breeding programs of Pacific oysters in China is initiated since 2006 and developed the genetically improved strain with fast-growing trait.However,little is known about the metabolic signatures of the fast-growing trait.In the present study,the non-targeted metabolomics was performed to analyze the metabolic signatures of adductor muscle tissue in one-year old Pacific oysters from fast-growing strain and the wild population.A total of 7767 and 10174 valid peaks were extracted and quantified in ESI^(+)and ESI^(−)modes,resulting in 399 and 381 annotated metabolites,respectively.PCA and OPLS-DA revealed that considerable separation among samples from fastgrowing strain and wild population,suggesting the differences in metabolic signatures.Meanwhile,81 significantly different metabolites(SDMs)were identified in the comparisons between fast-growing strain and wild population,based on the strict thresholds.It was found that there were highly correlation and conserved coordination among these SDMs.KEGG enrichment analysis indicated that the SDMs were tightly related to pantothenate and CoA biosynthesis,steroid hormone biosynthesis,riboflavin metabolism,and arginine and proline metabolism.Of them,the CoA biosynthesis and metabolism,affected by pantetheine and pantothenic acid,might be important for the growth of Pacific oysters under artificial selective breeding.The study provides the comprehensive views of metabolic signatures in response to artificially selective breeding,and is helpful to better understand the molecular mechanism of fastgrowing traits in Pacific oysters.展开更多
Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia.However,its wood is low quality with low density,and poor strength,durability,and dimensional stability.This study deter...Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia.However,its wood is low quality with low density,and poor strength,durability,and dimensional stability.This study determined the effects of impregnation with monoethylene glycol(MEG)and nano-SiO2 on the characteristics of sengon wood,including its dimensional stability and density.Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain,anti-swelling efficiency,water uptake,bulking effect,and density.The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction.The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5%MEGSiO2.展开更多
The dynamics of changes in body shape of fast-growing and slow-growing strains of turbot Scophthalmus maximus, and of the differences in body shape between the two strains, were evaluated from 3 to 27 months of age. T...The dynamics of changes in body shape of fast-growing and slow-growing strains of turbot Scophthalmus maximus, and of the differences in body shape between the two strains, were evaluated from 3 to 27 months of age. The ratios of total length/body length, body width/body length and total length/body width were used as morphometric indices. The two strains exhibited different temporal trends in total length/body length but similar trends in body width/body length and total length/body width. Generally, body width/body length of the two strains increased with time and total length/body width decreased. Thus, the bodies of both fast-growing and slow-growing strains of turbot changed from a narrow to a more rounded shape. However, the ratio total length/body length was generally lower, body width/body length was mostly higher and total length/body width was consistently lower in the fast-growing strain than in the slowgrowing strain. Correlation analysis of the three shape ratios with body weight showed that total length/body length and total length/body width were unsuitable, and that width/body length was suitable, for use as a phenotypic marker for selective breeding of turbot for growth in weight.展开更多
To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic r...To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic resin,Chinese fir was impregnated with a shellac solution.Since the shellac solution was difficult to penetrate into fast-growing Chinese fir,so microwave pretreatment was used to irradiate the wood to improve the permeability.This study investigated the effects of four factors,including the content of moisture in the wood before it was microwaved,the chamber pressure of microwave,the time of microwaving and the vacuum impregnation on the mechanical properties of Chinese fir wood.When the moisture content of wood before microwave was approximately 50%–60%,after microwaving and impregnation,the ultimate strength in static bending(modulus of rupture[MOR])and strength in compression perpendicular to the grain(SCPG)of the wood increased significantly.A microwave time of 100 seconds was more effective at improving the MOR and SCPG of the wood.If the wood was microwaved for too short or long period of time,the microwave pretreatment was not effective.When the samples were immersed in shellac for a longer period,the MOR and SCPG of Chinese fir gradually increased,but when the wood was impregnated for more than 12 hours,the increases were not significant.After the shellac penetrated the Chinese fir wood,it spread on the inner wall surface of tracheid to form a shellac film and easily formed plug-like deposits in microcapillaries.The use of Fourier-transform infrared spectroscopy,scanning electron microscopy and scanning electron microscopy-energy dispersion x-ray indicated that the microwave pretreatment can destroy the pit membranes on tracheids and facilitate the ability of shellac to penetrate the channel.展开更多
The flow of foreign direct investment(FDI)into a country can benefit both the investing entity and host government.This study employed panel analysis to examine the factors that determine the direction of FDI to the f...The flow of foreign direct investment(FDI)into a country can benefit both the investing entity and host government.This study employed panel analysis to examine the factors that determine the direction of FDI to the fast-growing BRICS(Brazil,Russia,India,China,and South Africa)and MINT(Mexico,Indonesia,Nigeria,and Turkey)countries.First,we used a pooled time-series cross sectional analysis of data from 2001 to 2011 to estimate and model the determinants of FDI for three samples:BRICS only,MINT only,and BRICS and MINT combined.Then,a fixed effects approach was employed to provide the model for BRICS and MINT combined.The results demonstrate that market size,infrastructure availability,and trade openness play the most significant roles in attracting FDI to BRICS and MINT,while the roles of availability of natural resources and institutional quality are insignificant.To sustain and promote FDI inflow,the governments of BRICS and MINT must ensure that their countries remain attractive for investment by offering a level playing field for investors and political stability.BRICS and MINT governments also need to invest more in their human capital to ensure that their economies can absorb substantial skills and technology spillovers from FDI and promote sustainable long-term economic growth.This study is significant because it contributes to the literature on determinants of FDI by extending the scope of previous studies that often focused on BRICS only.展开更多
The purpose of the article is to compare the conditions of development and support of fast-growing companies in European countries, Asian countries, and Russia. The comparative analysis performed is of interest as cer...The purpose of the article is to compare the conditions of development and support of fast-growing companies in European countries, Asian countries, and Russia. The comparative analysis performed is of interest as certain countries, including Russia, face the problem of economic slowdown. However, the fast-growing companies are powerful catalysts for the growth of the gross domestic product and the employment of the population. The conclusion of the study is that there are common patterns in ongoing support programs for fast-growing companies: long term, state support, innovative company orientation, and concessional financing. At the same time, there are fundamental differences in approaches to the state support for innovative companies. The first approach relates to the natural development of the fast-growing innovation companies and their support programs (Germany, Denmark); the second approach is aimed at artificially stimulating the growth of such companies (South Korea). In Russia there are institutional features of supporting fast-growing companies: small businesses are the most vulnerable part of the economic system and they require state support in crisis situations. Therefore, the experience of European and Asian countries in terms of supporting innovative and fast-growing companies can have a positive impact on the development of innovative companies in Russia. And definitely it is important to try to understand the nature of Russian innovative fast-growing companies: do we see them as entrepreneurial business as we do in the Western companies?展开更多
According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. T...According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. The type and structure of the driving motor and the compression spring were decided with force-balance analysis. The tilt problem of pruning robot was resolved by ADAMS and Matlab co-sim- ulation, and the control scheme of climbing mechanism was determined. The experiment results of the prototype indicate that pruning robot can climb tree trunk smoothly at a speed of 20 mm/s and cross the raised trunk. The pruning saw which is driven by the adjustable speed motor can cut the branches of 30 mm. And the residual amount of branches is less than 5 mm. Pruning robot can meet the practical requirements of the fast-growing forest pruning work.展开更多
The fast-growing procedure (FGP) provides a simple, high-yield and lead (Pb)-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot (...The fast-growing procedure (FGP) provides a simple, high-yield and lead (Pb)-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot (-240℃) substrate where a perovskite film grows immediately ac- companied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Proper- ties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3CI (MACI) affects the crystallization process and leads to full surface coverage, CH(NHz)2I (FAI) enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2.(1-x)FAI.xMACI, x=0.75, FGP-processed planar het- erojunction perovskite solar cells exhibit power conversion efficiencies (PCEs) exceeding 15% with suppressed hysteresis and excellent reproducibility.展开更多
The paper analyzed the basic characteristics of fast-growing and high-yield plantation, classified and identified the ecological problems in its development, and finally proposed the basic principles and corresponding...The paper analyzed the basic characteristics of fast-growing and high-yield plantation, classified and identified the ecological problems in its development, and finally proposed the basic principles and corresponding technical measures for fast-growing and high-yield plantation ecosystem management based on these problems.展开更多
The paper expounded the basic concept and principles of ecosystem management,and analyzed the state and trend of industrial plantation ecosystem management in other countries.Based on the analysis of typical case stud...The paper expounded the basic concept and principles of ecosystem management,and analyzed the state and trend of industrial plantation ecosystem management in other countries.Based on the analysis of typical case studies,the eco-economic benefits were evaluated for the management models of fast-growing and high-yield plantations.展开更多
[Objective] The aim was to explore growth performance of Phoebe bournei in seedling stage.[Method] Based on 17 superior plus trees of Phoebe bournei,a seedling cultivation test was conducted in Jindong Forest Farm in ...[Objective] The aim was to explore growth performance of Phoebe bournei in seedling stage.[Method] Based on 17 superior plus trees of Phoebe bournei,a seedling cultivation test was conducted in Jindong Forest Farm in Yongzhou,Hunan Province,exploring growth indices and analyzing seedling height and ground diameter.[Result] As per the selection rate at 20%,PB17,PB9 and PB12 were selected from the 17 species.Specifically,the seedling height averaged 36.52 cm of the selected three seedlings,which was higher by 16.1% compared with average of 17 species (31.45%).As for ground diameter,the selected species averaged 2.6 mm,which was higher (13.0%) compared with the average level (2.3 mm).[Conclusion]Both of seedling height and ground diameter reached extremely significant differences,which indicated that half-sib families of Phoebe bournei have rich variations,with selection and breeding potential.展开更多
We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modifi...We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde (PMF) co-condensed resin, diatomite, and 3-aminopropyl (diethoxy) methylsilane. We measured the weight percent gain (WPG), bulking, leaching, anti-swelling efficiency (ASE), wa- ter-repellent effectiveness (WRE), and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.展开更多
The genus Populus contains some of the most economically important tree species and hybrids in the world. We compared productivity of short and long-rotation poplar plantations using published data from 23 countries t...The genus Populus contains some of the most economically important tree species and hybrids in the world. We compared productivity of short and long-rotation poplar plantations using published data from 23 countries to determine if climate, particularly temperature, had any effect on the observed patterns of productivity. We discovered that climate factors (related to temperature) and clone origin (pure species or hybrids) slightly influenced productivity of long rotation forests more than short rotation plantations. While long rotation plantation productivity exhibited positive correlations with increasing temperature during winter and decreasing heat during summer, short rotation plantations showed weak positive relationship among productivity and increasing yearly temperature and the number of hot days. It was apparent that short rotation plantations productivity was less dependent on regional climatic variables or origin of clone. However, it appears that overall, regardless of the system, Populus species are generally adapted to a range of climatic conditions where they are planted.展开更多
Recent reports warned that planting leguminous trees under monocultures elevates nitrous oxide(N2O)emissions through N-rich litter inputs.We hypothesized that planting trees on sandy soil can avoid the legume-derived ...Recent reports warned that planting leguminous trees under monocultures elevates nitrous oxide(N2O)emissions through N-rich litter inputs.We hypothesized that planting trees on sandy soil can avoid the legume-derived boost of N2O emissions through limiting water availability for N2O production.Effects of planting legumes on methane(CH4)uptakes were also examined.N2O emissions and CH4uptakes were compared among five tropical tree plantation stands including three leguminous stands(Acacia auriculiformis,Acacia mangium,and Xylia xylocarpa)and two non-leguminous stands(Eucalyptus camaldulensis,and Hope a odorata).Due to lower water contents of the soil,the N2O fluxes in our study site were at the lower end of the tropical rain forests.As we hypothesized,no clear differences in N2O emissions were obs erved between leguminous and non-leguminous stands.CH4uptake rates in the present study were lower than those of other tropical forests.CH4uptakes in leguminous stands did not differ from those in non-leguminous stands.Overall,we demonstrated that planting leguminous trees on sandy soils has a potential to enable us to manage leguminous monoculture tree plantations without boosting N2O emissions or reducing CH4uptakes.展开更多
As Central Asia is a region with wide spread water scarcity as a result of excessive irrigation of agriculture, land use changes deserve research about potential impacts on the already strained water resources. Poplar...As Central Asia is a region with wide spread water scarcity as a result of excessive irrigation of agriculture, land use changes deserve research about potential impacts on the already strained water resources. Poplars have a long tradition as agroforestry tree across Central Asia, while paulownia is new to the region, but has been gaining extreme attention as a potential plantation and/or agroforestry tree. Therefore, the water productivity of those two tree species is investigated here on 3-year-old trees, in order to provide insights in how far the newly introduced Paulownia could put additional strain on water resources compared to paulownia. Poplar (<em>P. deltoides</em> × <em>nigra</em>) increased the stem biomass by 5.4 kg at an average water consumption of 4.18 l/d (water productivity 6.79 g/l). Paulownia’s (<em>Paulownia tomentosa</em> × <em>fortunei</em>) stem biomass grew by 4.81 kg at 2.36 l/d in average (water productivity 11.9 g/l). Expanding paulownia would not exert more pressure on Central Asia’s water resources than an expansion of poplar.展开更多
There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in...There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in the lower troposphere.Also,the linear mechanism of baroclinic disturbance development which is noted restricted by the critical baroclinity was not studied sufficiently.The realistic critical baroclinity and disturbance development are discussed in this study.It will be shown that the critical condition of instability and typical time and space scales of disturbances de- pend on three-dimensional structures of atmosphere and sphericity of the earth,other than the horizontal temperature gradient alone.The variant behaviour of atmospheric disturbances depends highly on their specific scales that may be described by the same theoretical model.Thus,there would be no substantial differences in the basic instability mecha- nism of many disturbances including the polar lows and explosive cyclones.展开更多
The paper firstly reviewed industrial plantation development in the main forestry countries worldwide, and then summarized the state and trend of the R & D of industrial plantation in foreign countries in terms of...The paper firstly reviewed industrial plantation development in the main forestry countries worldwide, and then summarized the state and trend of the R & D of industrial plantation in foreign countries in terms of genetic improvement, breeding techniques, site evaluation techniques, density control techniques, long-term productivity maintenance techniques and diseases and pests control techniques. In the meantime, the three management models employed in industrial plantations abroad was introduced, i.e. intensive management, oriented management, and enterprise-based management and integration of forest, industry and paper-making, based on which four suggestions were proposed through summarizing the successful experiences in industrial plantation development abroad to facilitate the development of fast-growing and high-yield plantation in China from the technical perspective.展开更多
基金supported by grants from the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(Nos.2021ZLGX03 and 2022LZGCQY010)the China Agriculture Research System Project(No.CARS-49).
文摘Pacific oyster(Crassostrea gigas)is one of the most important mollusks cultured all around the world.Selective breeding programs of Pacific oysters in China is initiated since 2006 and developed the genetically improved strain with fast-growing trait.However,little is known about the metabolic signatures of the fast-growing trait.In the present study,the non-targeted metabolomics was performed to analyze the metabolic signatures of adductor muscle tissue in one-year old Pacific oysters from fast-growing strain and the wild population.A total of 7767 and 10174 valid peaks were extracted and quantified in ESI^(+)and ESI^(−)modes,resulting in 399 and 381 annotated metabolites,respectively.PCA and OPLS-DA revealed that considerable separation among samples from fastgrowing strain and wild population,suggesting the differences in metabolic signatures.Meanwhile,81 significantly different metabolites(SDMs)were identified in the comparisons between fast-growing strain and wild population,based on the strict thresholds.It was found that there were highly correlation and conserved coordination among these SDMs.KEGG enrichment analysis indicated that the SDMs were tightly related to pantothenate and CoA biosynthesis,steroid hormone biosynthesis,riboflavin metabolism,and arginine and proline metabolism.Of them,the CoA biosynthesis and metabolism,affected by pantetheine and pantothenic acid,might be important for the growth of Pacific oysters under artificial selective breeding.The study provides the comprehensive views of metabolic signatures in response to artificially selective breeding,and is helpful to better understand the molecular mechanism of fastgrowing traits in Pacific oysters.
文摘Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia.However,its wood is low quality with low density,and poor strength,durability,and dimensional stability.This study determined the effects of impregnation with monoethylene glycol(MEG)and nano-SiO2 on the characteristics of sengon wood,including its dimensional stability and density.Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain,anti-swelling efficiency,water uptake,bulking effect,and density.The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction.The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5%MEGSiO2.
基金Supported by the Earmarked Fund for Modern Agro-Industry Technology Research System(No.CARS-50-G01)the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A408-8)
文摘The dynamics of changes in body shape of fast-growing and slow-growing strains of turbot Scophthalmus maximus, and of the differences in body shape between the two strains, were evaluated from 3 to 27 months of age. The ratios of total length/body length, body width/body length and total length/body width were used as morphometric indices. The two strains exhibited different temporal trends in total length/body length but similar trends in body width/body length and total length/body width. Generally, body width/body length of the two strains increased with time and total length/body width decreased. Thus, the bodies of both fast-growing and slow-growing strains of turbot changed from a narrow to a more rounded shape. However, the ratio total length/body length was generally lower, body width/body length was mostly higher and total length/body width was consistently lower in the fast-growing strain than in the slowgrowing strain. Correlation analysis of the three shape ratios with body weight showed that total length/body length and total length/body width were unsuitable, and that width/body length was suitable, for use as a phenotypic marker for selective breeding of turbot for growth in weight.
基金the 2018 Forestry Science and Technology Research Project by Forestry Department of Fujian Province(No.2018-26)Science and Technology Innovation Special Fund Project of Fujian Agriculture and Forestry University(CXZX2019111S)+1 种基金National Natural Science Foundation of China(31971593,32071688)the Natural Science Foundation of Fujian Province Department of Science and Technology(2019J01386).
文摘To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic resin,Chinese fir was impregnated with a shellac solution.Since the shellac solution was difficult to penetrate into fast-growing Chinese fir,so microwave pretreatment was used to irradiate the wood to improve the permeability.This study investigated the effects of four factors,including the content of moisture in the wood before it was microwaved,the chamber pressure of microwave,the time of microwaving and the vacuum impregnation on the mechanical properties of Chinese fir wood.When the moisture content of wood before microwave was approximately 50%–60%,after microwaving and impregnation,the ultimate strength in static bending(modulus of rupture[MOR])and strength in compression perpendicular to the grain(SCPG)of the wood increased significantly.A microwave time of 100 seconds was more effective at improving the MOR and SCPG of the wood.If the wood was microwaved for too short or long period of time,the microwave pretreatment was not effective.When the samples were immersed in shellac for a longer period,the MOR and SCPG of Chinese fir gradually increased,but when the wood was impregnated for more than 12 hours,the increases were not significant.After the shellac penetrated the Chinese fir wood,it spread on the inner wall surface of tracheid to form a shellac film and easily formed plug-like deposits in microcapillaries.The use of Fourier-transform infrared spectroscopy,scanning electron microscopy and scanning electron microscopy-energy dispersion x-ray indicated that the microwave pretreatment can destroy the pit membranes on tracheids and facilitate the ability of shellac to penetrate the channel.
文摘The flow of foreign direct investment(FDI)into a country can benefit both the investing entity and host government.This study employed panel analysis to examine the factors that determine the direction of FDI to the fast-growing BRICS(Brazil,Russia,India,China,and South Africa)and MINT(Mexico,Indonesia,Nigeria,and Turkey)countries.First,we used a pooled time-series cross sectional analysis of data from 2001 to 2011 to estimate and model the determinants of FDI for three samples:BRICS only,MINT only,and BRICS and MINT combined.Then,a fixed effects approach was employed to provide the model for BRICS and MINT combined.The results demonstrate that market size,infrastructure availability,and trade openness play the most significant roles in attracting FDI to BRICS and MINT,while the roles of availability of natural resources and institutional quality are insignificant.To sustain and promote FDI inflow,the governments of BRICS and MINT must ensure that their countries remain attractive for investment by offering a level playing field for investors and political stability.BRICS and MINT governments also need to invest more in their human capital to ensure that their economies can absorb substantial skills and technology spillovers from FDI and promote sustainable long-term economic growth.This study is significant because it contributes to the literature on determinants of FDI by extending the scope of previous studies that often focused on BRICS only.
文摘The purpose of the article is to compare the conditions of development and support of fast-growing companies in European countries, Asian countries, and Russia. The comparative analysis performed is of interest as certain countries, including Russia, face the problem of economic slowdown. However, the fast-growing companies are powerful catalysts for the growth of the gross domestic product and the employment of the population. The conclusion of the study is that there are common patterns in ongoing support programs for fast-growing companies: long term, state support, innovative company orientation, and concessional financing. At the same time, there are fundamental differences in approaches to the state support for innovative companies. The first approach relates to the natural development of the fast-growing innovation companies and their support programs (Germany, Denmark); the second approach is aimed at artificially stimulating the growth of such companies (South Korea). In Russia there are institutional features of supporting fast-growing companies: small businesses are the most vulnerable part of the economic system and they require state support in crisis situations. Therefore, the experience of European and Asian countries in terms of supporting innovative and fast-growing companies can have a positive impact on the development of innovative companies in Russia. And definitely it is important to try to understand the nature of Russian innovative fast-growing companies: do we see them as entrepreneurial business as we do in the Western companies?
基金supported by the Science and Technology Development Program of Shandong Province(Grant No.2013GNC11203)the National Natural Science Foundation of China(Grant Nos.51475278&3110146)the National Key Technology R&D Program(Grant No.2014BAD08B01-2)
文摘According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. The type and structure of the driving motor and the compression spring were decided with force-balance analysis. The tilt problem of pruning robot was resolved by ADAMS and Matlab co-sim- ulation, and the control scheme of climbing mechanism was determined. The experiment results of the prototype indicate that pruning robot can climb tree trunk smoothly at a speed of 20 mm/s and cross the raised trunk. The pruning saw which is driven by the adjustable speed motor can cut the branches of 30 mm. And the residual amount of branches is less than 5 mm. Pruning robot can meet the practical requirements of the fast-growing forest pruning work.
基金financially supported by the National Basic Research Program of China (973 Program) (2015CB932203)the National Natural Science Foundation of China (61377025, 91433203, and 11121091)+2 种基金the Young 1000 Talents Global Recruitment Program of Chinasupported by the US Office of Naval Research under contract N00014-15-1-2244the support from the US National Science Foundation (DMR-1305913 and OIA-1538893)
文摘The fast-growing procedure (FGP) provides a simple, high-yield and lead (Pb)-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot (-240℃) substrate where a perovskite film grows immediately ac- companied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Proper- ties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3CI (MACI) affects the crystallization process and leads to full surface coverage, CH(NHz)2I (FAI) enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2.(1-x)FAI.xMACI, x=0.75, FGP-processed planar het- erojunction perovskite solar cells exhibit power conversion efficiencies (PCEs) exceeding 15% with suppressed hysteresis and excellent reproducibility.
基金supported by the project of "Research on Comprehensive Management Techniques for Fast-growing and High-yield Plantation Ecosystem" under "Eleventh Five-year" Plan for National Science and Technology Support (2006BAD24B1003)
文摘The paper analyzed the basic characteristics of fast-growing and high-yield plantation, classified and identified the ecological problems in its development, and finally proposed the basic principles and corresponding technical measures for fast-growing and high-yield plantation ecosystem management based on these problems.
基金supported by the project of "Research on Comprehensive Management Techniques for Fast-growing and High-yield Plantation Ecosystem" in "Eleventh Five-year" Plan for National Science and Technology Support (2006BAD24B1003)
文摘The paper expounded the basic concept and principles of ecosystem management,and analyzed the state and trend of industrial plantation ecosystem management in other countries.Based on the analysis of typical case studies,the eco-economic benefits were evaluated for the management models of fast-growing and high-yield plantations.
基金Supported by Hunan Forestry Scientific Research(2010-07)~~
文摘[Objective] The aim was to explore growth performance of Phoebe bournei in seedling stage.[Method] Based on 17 superior plus trees of Phoebe bournei,a seedling cultivation test was conducted in Jindong Forest Farm in Yongzhou,Hunan Province,exploring growth indices and analyzing seedling height and ground diameter.[Result] As per the selection rate at 20%,PB17,PB9 and PB12 were selected from the 17 species.Specifically,the seedling height averaged 36.52 cm of the selected three seedlings,which was higher by 16.1% compared with average of 17 species (31.45%).As for ground diameter,the selected species averaged 2.6 mm,which was higher (13.0%) compared with the average level (2.3 mm).[Conclusion]Both of seedling height and ground diameter reached extremely significant differences,which indicated that half-sib families of Phoebe bournei have rich variations,with selection and breeding potential.
基金supported by Program for New Century Excellent Talents in University(NCET-10-0311)the National Natural Science Foundation of China(31000271)the Fundamental Research Funds for the Central Universities(DL11BB29)
文摘We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde (PMF) co-condensed resin, diatomite, and 3-aminopropyl (diethoxy) methylsilane. We measured the weight percent gain (WPG), bulking, leaching, anti-swelling efficiency (ASE), wa- ter-repellent effectiveness (WRE), and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.
文摘The genus Populus contains some of the most economically important tree species and hybrids in the world. We compared productivity of short and long-rotation poplar plantations using published data from 23 countries to determine if climate, particularly temperature, had any effect on the observed patterns of productivity. We discovered that climate factors (related to temperature) and clone origin (pure species or hybrids) slightly influenced productivity of long rotation forests more than short rotation plantations. While long rotation plantation productivity exhibited positive correlations with increasing temperature during winter and decreasing heat during summer, short rotation plantations showed weak positive relationship among productivity and increasing yearly temperature and the number of hot days. It was apparent that short rotation plantations productivity was less dependent on regional climatic variables or origin of clone. However, it appears that overall, regardless of the system, Populus species are generally adapted to a range of climatic conditions where they are planted.
基金supported by the grant from Grant-in-Aid for JSPS Fellowes(number 25·2647)to TMthe MEXT grant-in-aid 22255002 to KK。
文摘Recent reports warned that planting leguminous trees under monocultures elevates nitrous oxide(N2O)emissions through N-rich litter inputs.We hypothesized that planting trees on sandy soil can avoid the legume-derived boost of N2O emissions through limiting water availability for N2O production.Effects of planting legumes on methane(CH4)uptakes were also examined.N2O emissions and CH4uptakes were compared among five tropical tree plantation stands including three leguminous stands(Acacia auriculiformis,Acacia mangium,and Xylia xylocarpa)and two non-leguminous stands(Eucalyptus camaldulensis,and Hope a odorata).Due to lower water contents of the soil,the N2O fluxes in our study site were at the lower end of the tropical rain forests.As we hypothesized,no clear differences in N2O emissions were obs erved between leguminous and non-leguminous stands.CH4uptake rates in the present study were lower than those of other tropical forests.CH4uptakes in leguminous stands did not differ from those in non-leguminous stands.Overall,we demonstrated that planting leguminous trees on sandy soils has a potential to enable us to manage leguminous monoculture tree plantations without boosting N2O emissions or reducing CH4uptakes.
文摘As Central Asia is a region with wide spread water scarcity as a result of excessive irrigation of agriculture, land use changes deserve research about potential impacts on the already strained water resources. Poplars have a long tradition as agroforestry tree across Central Asia, while paulownia is new to the region, but has been gaining extreme attention as a potential plantation and/or agroforestry tree. Therefore, the water productivity of those two tree species is investigated here on 3-year-old trees, in order to provide insights in how far the newly introduced Paulownia could put additional strain on water resources compared to paulownia. Poplar (<em>P. deltoides</em> × <em>nigra</em>) increased the stem biomass by 5.4 kg at an average water consumption of 4.18 l/d (water productivity 6.79 g/l). Paulownia’s (<em>Paulownia tomentosa</em> × <em>fortunei</em>) stem biomass grew by 4.81 kg at 2.36 l/d in average (water productivity 11.9 g/l). Expanding paulownia would not exert more pressure on Central Asia’s water resources than an expansion of poplar.
文摘There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in the lower troposphere.Also,the linear mechanism of baroclinic disturbance development which is noted restricted by the critical baroclinity was not studied sufficiently.The realistic critical baroclinity and disturbance development are discussed in this study.It will be shown that the critical condition of instability and typical time and space scales of disturbances de- pend on three-dimensional structures of atmosphere and sphericity of the earth,other than the horizontal temperature gradient alone.The variant behaviour of atmospheric disturbances depends highly on their specific scales that may be described by the same theoretical model.Thus,there would be no substantial differences in the basic instability mecha- nism of many disturbances including the polar lows and explosive cyclones.
基金supported by the project of "Research on Comprehensive Management Techniques for Fast-growing and High-yield Plantation Ecosystem" under "Eleventh Five-year" Plan for National Science and Technology Support (2006BAD24B1003)
文摘The paper firstly reviewed industrial plantation development in the main forestry countries worldwide, and then summarized the state and trend of the R & D of industrial plantation in foreign countries in terms of genetic improvement, breeding techniques, site evaluation techniques, density control techniques, long-term productivity maintenance techniques and diseases and pests control techniques. In the meantime, the three management models employed in industrial plantations abroad was introduced, i.e. intensive management, oriented management, and enterprise-based management and integration of forest, industry and paper-making, based on which four suggestions were proposed through summarizing the successful experiences in industrial plantation development abroad to facilitate the development of fast-growing and high-yield plantation in China from the technical perspective.