Technical Efficiency Estimates of Scottish Agriculture: A Note

Within the UK there has been a lack of studies of technical efficiency at the Scottish level. This note compares the results obtained using Scottish data with a recent study by Hadley [Journal of Agricultural Economics (2006) Vol. 57, pp. 81–100] for English and Welsh farms. Four major sectors are investigated, namely: (i) cereals, (ii) dairy, (iii) sheep and (iv) beef over the period 1989 to 2004. Some distinct differences in efficiencies, returns to scale and causes of efficiency are found.     

用保形样条方法求解非定常对流扩散方程

在欧拉-拉格朗日分裂方法的基础上,本文发展了一种固定网格上的欧拉-拉格朗日分裂方法.保形样条方法(SPSM)被用来解决倒特征线插值问题.通过求解几个有精确解的例子,说明SPSM方法的解是单调无振荡的,并且数值耗散也是比较小的.     

NUMERICAL SIMULATIONS OF WHOLE FIELD BEHAVIOR FOR ROUND BUOYANT JET

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＳＯＦＷＨＯＬＥＦＩＥＬＤＢＥＨＡＶＩＯＲＦＯＲＲＯＵＮＤＢＵＯＹＡＮＴＪＥＴＬｉＷｅｉ，ＨｕａｉＷｅｎ－ｘｉｎ（ＷｕｈａｎＵｎｉｖｅｒｓｉｔｙｏｆＨｙｄｒａｕｌｉｃａｎｄＥｌｅｃｔｒｉｃＥｎｇｉｎｅｅｒｉｎｇ，...     

关于最优等效替代法的实质及其应用条件的研究

本文研究了经济分析基本方法之一最优等效替代法的实质,系统地导出了被评价方案的绝对经济指标与相对经济指标的关系,并结合典型案例分析指出了该方法的应用条件,对正确进行建设项目的经济评价具有现实意义。     

Simulation of leachate migration in leaky aquifers

A two-dimensional cross-section finite difference model is presented to simulate density dependent leachate migration in leaky aquifers. Unlike existing models, a new approach is adopted to couple the groundwater-flow equation and the hydrodynamic dispersion equation with the elimination of the intermediate step of calculating velocities. The concept of the reference density is employed, permitting increased accuracy (over pressure-based models) in the representation of the transport process. The model is then used to study the effect of several hydraulic and transport parameters on the flow pattern and plume migration which are found to be very sensitive to most of these parameters. Equiconcentration and equipotential lines are overlapped to provide a better understanding of the coupling effect.     

企业竞争策略中的成本效益分析方法

企业每一项经营决策都应该进行成本效益分析，市场竞争中可以根据本企业的成本曲线和需求曲线，预测出竞争策略实施后对内部成本和外部需求可能产生的影响，从而计算出某项决策的经济效果。     

杠杆融资项目净现值计算方法的比较与分析

负债融资具有杠杆效应,有节税收益。计算杠杆融资项目的净现值,如仍按全权益融资项目的方法计算,其结果会有所不同,直接影响投资决策的正确性。本文介绍三种西方常用的杠杆融资项目的净现值计算方法,并对其适用条件进行比较和分析。     

关于混联梯级水电站经济调度的研究

提出采用具有附加线性约束的网络规划法，可把混联梯级水电站分解为几个子网络，简化了每个子网络的求解计算，从而加速大电网复杂的经济调度的计算速度。     

自动化驼峰作业预想控制法

襄樊北站驼峰自动化控制系统于2001年11月28日正式投入运用,根据该系统在运用中出现的问题及产生原因,通过采用自动化驼峰作业预想控制法,将人的作业经验与自动化精确控制相结合,取得了扬长避短充分发挥自动控制作用、提高编组站驼峰作业能力的效果。