为了明确土地利用方式的变化与生态系统服务供给之间的关系,该文以黑河流域上游为研究区,基于SWAT(soil and water assessmenttool)模型和最小数据法分析了补偿价格变化对禁牧比例以及提供的水源涵养服务的影响。研究表明:1)放牧与禁牧...为了明确土地利用方式的变化与生态系统服务供给之间的关系,该文以黑河流域上游为研究区,基于SWAT(soil and water assessmenttool)模型和最小数据法分析了补偿价格变化对禁牧比例以及提供的水源涵养服务的影响。研究表明:1)放牧与禁牧情景下水源涵养服务产出率平均为25.27m3/hm2;2)SWAT模型能够较精确地模拟流域的水文过程,模型率定期和验证期的Nash-Sutcliffe效率系数分别达到0.81和0.88,R2分别为0.94和0.93,年平均径流量的相对误差分别为16.3%和15.6%。3)不同子流域内禁牧的机会成本存在差异,禁牧的平均机会成本为289.99元/hm2;4)不同补偿价格下新增草地禁牧比例及其提供的水源涵养服务的供给量不同。当所有子流域内的低质量草地全部禁牧后,1990-2000年间可提供水源涵养服务的总量为7.79×108m3,新增水源涵养服务量达到7.66×108m3。该文为生态补偿对象的空间选择与补偿标准的确定提供科学依据。展开更多
The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm,...The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square(LS) method and the maximum likelihood estimation(MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.展开更多
The quality prediction of tube hollow model based on the variance staged multiway partial least square (MPLS) method was proposed.The key aspects of staged decomposition of the productive data,calculation of the varia...The quality prediction of tube hollow model based on the variance staged multiway partial least square (MPLS) method was proposed.The key aspects of staged decomposition of the productive data,calculation of the variance value,modeling,and on-lined prediction in the variance-staged MPLS method were introduced.Based on the model,iterative optimal control method was used for quality control of tube hollow.The experimental results show that the obvious benefits of this method are low maintenance cost,good real time function,high reliability precision,and practical application to on-line prediction and optimization on the quality of tube hollow.展开更多
文摘为了明确土地利用方式的变化与生态系统服务供给之间的关系,该文以黑河流域上游为研究区,基于SWAT(soil and water assessmenttool)模型和最小数据法分析了补偿价格变化对禁牧比例以及提供的水源涵养服务的影响。研究表明:1)放牧与禁牧情景下水源涵养服务产出率平均为25.27m3/hm2;2)SWAT模型能够较精确地模拟流域的水文过程,模型率定期和验证期的Nash-Sutcliffe效率系数分别达到0.81和0.88,R2分别为0.94和0.93,年平均径流量的相对误差分别为16.3%和15.6%。3)不同子流域内禁牧的机会成本存在差异,禁牧的平均机会成本为289.99元/hm2;4)不同补偿价格下新增草地禁牧比例及其提供的水源涵养服务的供给量不同。当所有子流域内的低质量草地全部禁牧后,1990-2000年间可提供水源涵养服务的总量为7.79×108m3,新增水源涵养服务量达到7.66×108m3。该文为生态补偿对象的空间选择与补偿标准的确定提供科学依据。
基金Project(51165019)supported by the National Natural Science Foundation of ChinaProject(1308RJYA018)supported by Gansu Provincial Natural Science Fund,ChinaProject(2013-4-110)supported by Lanzhou Technology Development Program,China
文摘The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square(LS) method and the maximum likelihood estimation(MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.
基金Project(60674063) supported by the National Natural Science Foundation of China
文摘The quality prediction of tube hollow model based on the variance staged multiway partial least square (MPLS) method was proposed.The key aspects of staged decomposition of the productive data,calculation of the variance value,modeling,and on-lined prediction in the variance-staged MPLS method were introduced.Based on the model,iterative optimal control method was used for quality control of tube hollow.The experimental results show that the obvious benefits of this method are low maintenance cost,good real time function,high reliability precision,and practical application to on-line prediction and optimization on the quality of tube hollow.
