樟子松人工林热值与能量结构分析(Ⅱ)——凋落物的热值与能量动态和群落的能量净生产量与转化率

在生物量调查和热值测定的基础上,分析了24年生樟子松人工林凋落物的热值及能量季节动态、群落的净生产量及能量转化率。结果表明:林下植被凋落物的能量释放率高于樟子松凋落物的释放率,且凋落物释放量都主要集中在6、7、8月份。凋落物能量释放率以榆树枯叶和水曲柳叶最高,其他依次是樟子松枯叶>水曲柳叶梗>樟子松球果>樟子松树皮>樟子松枯枝。凋落物能量现存总量为205.49×109J/hm2;樟子松人工林群落能量年净生产量为344.45×109J/hm2,其中,樟子松林木能量年净生产量304.35×109J/(hm2.a),林下植被中能量净生产总量为40.10×109J/(hm2.a);能量累积比以樟子松人工林群落值最大,为7.44,其次是樟子松林木能量累积比为7.20,林下植被能量积累比最低;能量流动速率比为林下植被0.240>樟子松林木0.139>群落0.134;樟子松人工林群落的能量转化率为7.31%、樟子松林木和林下植被的能量转化率分别为6.46%和0.85%。

鼎湖山马尾松群落能量分配及其生产的动态

对鼎湖山马尾松群落各组分热值、能量现存量、能量净生产量及群落太阳能转化效率进行了研究。结果表明:(1)乔木层马尾松各器官热值相差不大,为19.02~20.30 kJ/g(总平均 19.34 kJ/g);灌木层植物热值低于乔木层,为16.55~18.78 kJ/g(总平均17.82 kJ/g);草本层植物热值低于灌木层,为13.07~16.16 kJ/g(总平均15.03 kJ/g)。(2)群落能量总现存量随时间而增加,且组分分配比例因年份不同而异。在 1990、1995和2000年分别为167 141.4、270 295.9和321 294.3 kJ/m2,其中乔木层占93.4%、79.8%和86.7%,林下层占3.5%、10.6%和7.2%,而地表现存凋落物层仅占3.2%、9.5%和6.1%。(3)群落在1990~1995年和1995~2000年期间能量净生产每年分别为 1 7083. 2 kJ/m2 和 21 571. 8 kJ/m2,其中乔木层占 96. 6%和95 5%,林下层仅占3.4%和5.0%。所有能量生产量中,群落自身增长能量(即年能量存留量)占 72.7%和57.6%,而释放到其它子系统的能量占27.3%和42.4%。(4)群落太阳能转化效率在 1990~1995 年和 1995~2001年分别为0.759%和0.958%,10年平均为0.873%。

多目标风力发电机叶片外形参数优化设计

针对风力发电机叶片外形设计问题,文中提出了一种用于优化风力发电机叶片的优化工具包CoBOLDT(计算叶片优化和载荷缩小工具)。该优化工具包利用多目标禁忌搜索算法(Multiple Objective Tabu Search,MOTS)来控制样条函数参数化模块,采用快速几何形状生成和固定叶片元件动量(Blade Element Momentum,BEM)代码来优化初始的风力发电机叶片设计。研究中所采用的目标函数是在固定风速为50m/s条件下的年能量生产量(AEP)和叶片根部弯矩(MY0)。文中使用9个变量来定义叶片弦(4个变量)、叶片扭曲(4个变量)和叶片半径(1个变量);在整个优化过程中,定义了诸多二元约束以限制噪声的产生,从而允许在陆地上运输以及在发电机运行的所有阶段期间控制空气动力学条件。测试结果表明,MOTS能够快速和有效地找到优化的设计;优化的叶片设计可以使初始叶片的AEP提高5%,并具有相同的叶片根部弯矩,或者在初始AEP下将MY0降低7.5%。此外,文中还允许通过在每个叶片函数中引入更多参数来增加设计的灵活性。

Development of process energy intensity formula under different state variables

In a production process, the actual energy consumption is greatly affected by the production state. Certain processing operations are classified into six states, including normal production, abnormal production, planned overhaul, unplanned overhaul, transitional period from unplanned overhaul to normal production (referred for short as unplanned transition) and transitional period from planned overhaul to normal production (referred for short as planned transition). The article takes the analysis of relationship between different states of a certain processing operation and corresponding energy consumptions as a startup point to develop a process energy intensity formula with variables of operating rate, yielding rate and operating frequency, etc. This process energy intensity formula can be used to analyze effectively the pattern of impact exerted by different state variables on energy consumption.

Energy Balance in Crop Production

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.

Study of Water Injection Efficiency through Modern Geological-Mathematical Models in Guneshly Field

Guneshli is a unique oil field for.its huge oil reserves. Fasila layer is one of the main productive series with more than 3,300 tons of oil production per year. It is an important task to continue efficently develop this object. Development of Fasila was analysed based on geological-mathematical models, production performance was predicted through use of advanced ＂evolution＂ modeling program. In addition, the impact of water injection from deep water Guneshly was identified and relavant proposals were put forward.

Related turbulent momentum and passive scalar transfer in a turbulent channel flow

Direct numerical simulation was carried out to investigate the correlation between the momentum and passive scalar transfer in a turbulent channel flow with Re_(τ)=u_(τ)δ/ν=180 and Pr=0.71,where u_(τ)is the friction velocity,δis the channel half width,andνis the kinematic viscosity.The one-point and two-point energy transfer and the corresponding scalar transfer are of particular interest.There is a significant positive correlation between the one-point energy and scalar transfer,particularly near the wall,and the correlation between the two production terms is always larger than that between the other terms.By resorting to the Karman-Howarth-Monin-Hill equation and the scale-by-scale scalar transfer budget equation,we explored the two-point energy and scalar transfer at two different vertical locations(i.e.,one location close to the wall y^(+)=10 and the other location slightly away from the wall y^(+)=60).An inverse interscale transfer phenomenon of the energy and scalar is observed in the spanwise direction at y^(+)=10,which is caused by the corresponding streak stretching,whereas along the streamwise and the vertical directions a forward interscale energy and scalar transfer phenomenon is observed.The physical mechanisms(e.g.,production,dissipation,and viscous diffusion terms)contributing to the two-point energy transfer closely resemble those in the two-point scalar transfer.The intrinsic correlation between both the two-point energy and scalar transfer can find its roots in the similarity between the momentum and scalar streaks.

Analysis of Generalized Ghost Dark Energy in LQC and Galileon Gravity

A so-called ghost dark energy was recently proposed to explain the present acceleration of the universe.The energy density of ghost dark energy,which originates from Veneziano ghost of Quantum Chromodynamics(QCD),in a time dependent background,can be written in the form,ρD=αH + βH^2 where H is the Hubble parameter.We investigate the generalized ghost dark energy(GGDE) model in the setup of loop quantum Cosmology(LQC) and Galileon Cosmology.We study the cosmological implications of the models.We also obtain the equation of state and the deceleration parameters and differential equations governing the evolution of this dark energy model for LQC and Galileon Cosmology.