With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosi...With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosity was the highest in the Casuarina equisetifolia forest (46.168%), but the lowest in the Encalyptus robusta forest (39.46%). The soil capillary porosity was the highest in the Acacia mangium forest (22.57%), but the lowest in the secondary forest (18.95%). The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic (pH 4.5-5.5), and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents (with a mean value of 2.29 mg/kg) and ammonium N contents (with a mean value of 3.93 mg/kg). For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.展开更多
A class of nonlocal boundary value probl em s for elliptic systems in the unbounded domains are considered. Under suitable c onditions, the existence of solution and the comparison theorem for the boundary value prob...A class of nonlocal boundary value probl em s for elliptic systems in the unbounded domains are considered. Under suitable c onditions, the existence of solution and the comparison theorem for the boundary value problems are studied.展开更多
Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks...Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-(1) system operation performance; (2) agricultural productivity and economics; (3) financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute (IWMI) and Food and Agriculture Organization (FAO). Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System (MARI1S), Lucban, Garab and Divisoria Communal Irrigation Systems (CIS), respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.展开更多
Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transforma...Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.展开更多
The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resol...The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.展开更多
The asymptotical stability in probability is studied for diffusion processes and regime-switching diffusion processes in this work. For diffusion processes, some criteria based on the integrability of the functionals ...The asymptotical stability in probability is studied for diffusion processes and regime-switching diffusion processes in this work. For diffusion processes, some criteria based on the integrability of the functionals of the coefficients are given, which yield a useful comparison theorem on stability with respect to some nonlinear systems. For regime-switching diffusion processes, some criteria based on the idea of a variational formula are given. Both state-independent and state-dependent regime-switching diffusion processes are investigated in this work. These conditions are easily verified and are shown to be sharp by examples.展开更多
This paper investigates some important properties of Z, the martingale integrant of the backward stochastic differential equations, which is the second process of the solution. These include the backward stochastic vi...This paper investigates some important properties of Z, the martingale integrant of the backward stochastic differential equations, which is the second process of the solution. These include the backward stochastic viability property, bounded property and the comparison theorem. To explain the theoretical results, the authors apply them to study a financial contingent claim pricing problem. The replication portfolio process can be characterized clearly.展开更多
Improving management of soil organic carbon(SOC)has been considered as a substantial mitigation strategy to climate change.Management such as stubble retention(SR),conservation tillage(ZT),and fertilization are recomm...Improving management of soil organic carbon(SOC)has been considered as a substantial mitigation strategy to climate change.Management such as stubble retention(SR),conservation tillage(ZT),and fertilization are recommended for both promoting production and accumulating SOC.However,whether such management practices can cause net increase in SOC or just a slow-down of SOC decline largely depends on the current status of SOC for a given region.This paper synthesized the available SOC data in the croplands of China,and analysed the change of SOC in the top 20 cm soil as a result of management change.The results showed that,on average,SOC increased by 18.3%through SR,by 9.1%through ZT,and by 12.4%,36.9%and 41.5%through application of inorganic(IF),organic(OF)and combined inorganic and organic fertilizers(IOF),respectively,compared to those under stubble removal,conventional tillage and no fertilization.Under SR,ZT,IF,OF and IOF,SOC increased by 16.0%,10.2%,8.2%,32.2%and41.3%,respectively,at the end of the trials compared with the initial values at the start of the trials.Our analysis also showed that in Northeast and Northwest China,SOC in agricultural soils is still decreasing due to cultivation.In North and South China,however,SOC appears to have reached a new equilibrium of low SOC state after a long cultivation history,and soils have greater potential to sequester C.Our analysis highlights the need of taking account of the baseline status to assess the net soil C balance over time and space.展开更多
We consider a reaction-diffusion model which describes the spatial Wolbachia spread dynamics for a mixed population of infected and uninfected mosquitoes. By using linearization method, comparison principle and Leray-...We consider a reaction-diffusion model which describes the spatial Wolbachia spread dynamics for a mixed population of infected and uninfected mosquitoes. By using linearization method, comparison principle and Leray-Schauder degree theory, we investigate the influence of diffusion on the Wolbachia infection dynamics.After identifying the system parameter regions in which diffusion alters the local stability of constant steadystates, we find sufficient conditions under which the system possesses inhomogeneous steady-states. Surprisingly,our mathematical analysis, with the help of numerical simulations, indicates that diffusion is able to lower the threshold value of the infection frequency over which Wolbachia can invade the whole population.展开更多
In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or n...In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or noncompact manifolds,in which some basic tools,such as the weighted volume comparison theorem and the weak maximum principle at infinity,are used.A lower bound estimate for the scalar curvature is also obtained.展开更多
基金Supported by Special Fund for Technological Development and Research of Provincial Scientific Research Institutions(KYYS-2015-16)~~
文摘With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosity was the highest in the Casuarina equisetifolia forest (46.168%), but the lowest in the Encalyptus robusta forest (39.46%). The soil capillary porosity was the highest in the Acacia mangium forest (22.57%), but the lowest in the secondary forest (18.95%). The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic (pH 4.5-5.5), and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents (with a mean value of 2.29 mg/kg) and ammonium N contents (with a mean value of 3.93 mg/kg). For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.
文摘A class of nonlocal boundary value probl em s for elliptic systems in the unbounded domains are considered. Under suitable c onditions, the existence of solution and the comparison theorem for the boundary value problems are studied.
文摘Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-(1) system operation performance; (2) agricultural productivity and economics; (3) financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute (IWMI) and Food and Agriculture Organization (FAO). Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System (MARI1S), Lucban, Garab and Divisoria Communal Irrigation Systems (CIS), respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.
文摘Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.
基金supported by the Joint Fund for Fostering Talents of National Natural Science Foundation of China and Henan Province(Grant No.U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No.2012PNTT01)+4 种基金the Postdoctoral Grant of China(Grant Nos.2011M501446,2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province(Grant No.122300410169)The Key Science and Technology Foundation of Zhengzhou City(Grant Nos.131PPTGG411-6,131PCXTD594)the Doctor Fund of Zhengzhou University of Light Industry(Grant No.2011BSJJ031)the Fundamental Research Funds for the Central Universities(Grant No.K5051204003)
文摘The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.
基金supported by National Natural Science Foundation of China (Grant Nos. 11301030, 11401169 and 11431014)Key Scientific Research Projects of Henan Province (Grant No. 16A110010)
文摘The asymptotical stability in probability is studied for diffusion processes and regime-switching diffusion processes in this work. For diffusion processes, some criteria based on the integrability of the functionals of the coefficients are given, which yield a useful comparison theorem on stability with respect to some nonlinear systems. For regime-switching diffusion processes, some criteria based on the idea of a variational formula are given. Both state-independent and state-dependent regime-switching diffusion processes are investigated in this work. These conditions are easily verified and are shown to be sharp by examples.
基金supported by the National Natural Science Foundation of China under Grant Nos.10921101, 61174092,11026185 and 11101242the National Science Foundation for Distinguished Young Scholars of China under Grant No.11125102+1 种基金the Natural Science Foundation of Shandong Province,China under Grant No.ZR2010AQ004the Independent Innovation Foundation of Shandong University under Grant No. 2009TS036
文摘This paper investigates some important properties of Z, the martingale integrant of the backward stochastic differential equations, which is the second process of the solution. These include the backward stochastic viability property, bounded property and the comparison theorem. To explain the theoretical results, the authors apply them to study a financial contingent claim pricing problem. The replication portfolio process can be characterized clearly.
基金Supported by the National Basic Research Program of China(No.2010CB950604)the National Natural Science Foundation of China(No.41075108)
文摘Improving management of soil organic carbon(SOC)has been considered as a substantial mitigation strategy to climate change.Management such as stubble retention(SR),conservation tillage(ZT),and fertilization are recommended for both promoting production and accumulating SOC.However,whether such management practices can cause net increase in SOC or just a slow-down of SOC decline largely depends on the current status of SOC for a given region.This paper synthesized the available SOC data in the croplands of China,and analysed the change of SOC in the top 20 cm soil as a result of management change.The results showed that,on average,SOC increased by 18.3%through SR,by 9.1%through ZT,and by 12.4%,36.9%and 41.5%through application of inorganic(IF),organic(OF)and combined inorganic and organic fertilizers(IOF),respectively,compared to those under stubble removal,conventional tillage and no fertilization.Under SR,ZT,IF,OF and IOF,SOC increased by 16.0%,10.2%,8.2%,32.2%and41.3%,respectively,at the end of the trials compared with the initial values at the start of the trials.Our analysis also showed that in Northeast and Northwest China,SOC in agricultural soils is still decreasing due to cultivation.In North and South China,however,SOC appears to have reached a new equilibrium of low SOC state after a long cultivation history,and soils have greater potential to sequester C.Our analysis highlights the need of taking account of the baseline status to assess the net soil C balance over time and space.
基金supported by National Natural Science Foundation of China (Grant Nos. 11471085, 91230104 and 11301103)Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT1226)+1 种基金Program for Yangcheng Scholars in Guangzhou (Grant No. 12A003S)Guangdong Innovative Research Team Program (Grant No. 2011S009)
文摘We consider a reaction-diffusion model which describes the spatial Wolbachia spread dynamics for a mixed population of infected and uninfected mosquitoes. By using linearization method, comparison principle and Leray-Schauder degree theory, we investigate the influence of diffusion on the Wolbachia infection dynamics.After identifying the system parameter regions in which diffusion alters the local stability of constant steadystates, we find sufficient conditions under which the system possesses inhomogeneous steady-states. Surprisingly,our mathematical analysis, with the help of numerical simulations, indicates that diffusion is able to lower the threshold value of the infection frequency over which Wolbachia can invade the whole population.
基金Project supported by the National Natural Science Foundation of China(Nos.10971066,11171254)
文摘In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or noncompact manifolds,in which some basic tools,such as the weighted volume comparison theorem and the weak maximum principle at infinity,are used.A lower bound estimate for the scalar curvature is also obtained.