The most appropriate method of energy balancing in crop production is the process analysis where fossil energy input is considered rather than manpower or solar energy. In our approach, fossil energy input is split to...The most appropriate method of energy balancing in crop production is the process analysis where fossil energy input is considered rather than manpower or solar energy. In our approach, fossil energy input is split to direct and indirect input components. Direct energy input includes the consumption of diesel fuel required for field operations taking into account the influences of location and management conditions. Moreover, energy consumption for construction of agricultural machines is also considered as direct energy input. Indirect energy inputs include seed material, plant protection agents, fertilizers and operation of machines. Production and utilisation of nitrogen （N） fertilizer represents by 50% of energy consumption in agricultural systems. Data from a field experiment conducted during 1995-2000 on a fertile sandy loess in the Hercynian dry region of central Germany were used to determine the energy efficiency of winter oilseed rape （Brassica napus L.） as affected by nitrogen （N） fertilization. Our results show that different N management strategies affect the energy balance of the seed oil. Lowest energy input and energy output occurred in the unfertilized crop. The energy efficiency was determined using the parameters energy gain （net energy output）, energy intensity （energy input per unit grain equivalent GE; term GE is used to express the contribution that crops make to the nutrition of monogastric beings）, and output/input ratio. The most favourable N rate for minimum energy intensity was 80 kg N hal while that needed for maximum energy gain was 160 kg ha1. Output/input ratio was the highest at 80 kg N ha-l.展开更多
Self-powered chaos signal generator is potentially useful in future medical system,such as low cost portable human healthy monitor and treatment without external power source.For both functional and power unit,the pow...Self-powered chaos signal generator is potentially useful in future medical system,such as low cost portable human healthy monitor and treatment without external power source.For both functional and power unit,the power level of electric energy generator and consumption is a key factor for self-powered system.In this paper,we have investigated the power consumption of three typical output modes of a simple chaos circuit.Analytical analysis for power consumption of fixed output mode is obtained for evaluating the power characteristics of chaos signal generator.Numerical calculations are given for predicting the power characteristics of periodical and chaotic output modes.This study is important for not only understanding the power consumption of chaos signal generator,but also guiding new self-powered chaos signal generator design.展开更多
文摘The most appropriate method of energy balancing in crop production is the process analysis where fossil energy input is considered rather than manpower or solar energy. In our approach, fossil energy input is split to direct and indirect input components. Direct energy input includes the consumption of diesel fuel required for field operations taking into account the influences of location and management conditions. Moreover, energy consumption for construction of agricultural machines is also considered as direct energy input. Indirect energy inputs include seed material, plant protection agents, fertilizers and operation of machines. Production and utilisation of nitrogen （N） fertilizer represents by 50% of energy consumption in agricultural systems. Data from a field experiment conducted during 1995-2000 on a fertile sandy loess in the Hercynian dry region of central Germany were used to determine the energy efficiency of winter oilseed rape （Brassica napus L.） as affected by nitrogen （N） fertilization. Our results show that different N management strategies affect the energy balance of the seed oil. Lowest energy input and energy output occurred in the unfertilized crop. The energy efficiency was determined using the parameters energy gain （net energy output）, energy intensity （energy input per unit grain equivalent GE; term GE is used to express the contribution that crops make to the nutrition of monogastric beings）, and output/input ratio. The most favourable N rate for minimum energy intensity was 80 kg N hal while that needed for maximum energy gain was 160 kg ha1. Output/input ratio was the highest at 80 kg N ha-l.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2013-35)Beijing Municipal Commission of Science and Technology(Grant No.Z131100006013005)
文摘Self-powered chaos signal generator is potentially useful in future medical system,such as low cost portable human healthy monitor and treatment without external power source.For both functional and power unit,the power level of electric energy generator and consumption is a key factor for self-powered system.In this paper,we have investigated the power consumption of three typical output modes of a simple chaos circuit.Analytical analysis for power consumption of fixed output mode is obtained for evaluating the power characteristics of chaos signal generator.Numerical calculations are given for predicting the power characteristics of periodical and chaotic output modes.This study is important for not only understanding the power consumption of chaos signal generator,but also guiding new self-powered chaos signal generator design.
