Shortages and fluctuations in precipitation are influential limiting factors for the sustainable cultivation of rain-fed winter wheat on the Loess Plateau of China. Plastic film mulching is one of the most effective w...Shortages and fluctuations in precipitation are influential limiting factors for the sustainable cultivation of rain-fed winter wheat on the Loess Plateau of China. Plastic film mulching is one of the most effective water management practices to improve soil moisture, and may be useful in the Loess Plateau for increasing soil water storage. A field experiment was conducted from July 2010 to June 2012 on the Loess Plateau to investigate the effects of mulching time and rates on soil water storage, evapotranspiration （ET）, water use efficiency （WUE）, and grain yield. Six treatments were conducted： （1） early mulching （starting 30 days after harvest） with whole mulching （EW）; （2） early mulching with half mulching （EH）; （3） early mulching with no mulching （EN）; （4） late mulching （starting 60 days after harvest） with whole mulching （LW）; （5） late mulching with half mulching （LH）; and （6） late mulching with no mulching （LN）. EW increased precipitation storage efficiency during the fallow periods of each season by 18.4 and 17.8%, respectively. EW improved soil water storage from 60 days after harvest to the booting stage and also outperformed LN by 13.8 and 20.9% in each growing season. EW also improved spike number per ha by 13.8 and 20.9% and grain yield by 11.7 and 17.4% during both years compared to LN. However, EW decreased WUE compared with LN. The overall results of this study demonstrated that EW could be a productive and efficient practice to improve wheat yield on the Loess Plateau of China.展开更多
对ANSI/ASHRAE/ASHE standard 170-2021《医疗设施通风》的主要修订内容进行了分析,包括:修改医用房间名称,将有较高设计要求的房间与其他房间分开并提出细化指标;增加值班状态,为医疗建筑节能运行提供方法依据;进一步明确各类医疗用房...对ANSI/ASHRAE/ASHE standard 170-2021《医疗设施通风》的主要修订内容进行了分析,包括:修改医用房间名称,将有较高设计要求的房间与其他房间分开并提出细化指标;增加值班状态,为医疗建筑节能运行提供方法依据;进一步明确各类医疗用房排风过滤效率。此外,对ASHRAE 170发展趋势进行了简要介绍,对未来发展进行了展望,以期为我国医疗建筑相关标准规范的制订/修订提供参考。展开更多
为提高风电机组系统的运行效率和稳定性,提出一种基于数据驱动的风电机组能效状态分析方法,实现对机组异常状态的高效检测与预警。首先从损耗与效率的角度出发,开展各因素对机组能效的影响分析,考虑到系统各部件能量损失主要体现在热量...为提高风电机组系统的运行效率和稳定性,提出一种基于数据驱动的风电机组能效状态分析方法,实现对机组异常状态的高效检测与预警。首先从损耗与效率的角度出发,开展各因素对机组能效的影响分析,考虑到系统各部件能量损失主要体现在热量方面,因此以温度参数为依据,建立基于能量流的能效状态指标体系。然后利用风电机组数据采集与监视控制(supervisory control and data acquisition,SCADA)系统采集数据,确定各参数基准区间,构建指标偏离度矩阵,利用改进的鲸鱼算法(improved whale optimization algorithm,IWOA)优化支持向量机,实现对能效异常状态的检测。同时引入能效异常指数来表征机组能效变化情况,利用自回归滑动平均模型-支持向量机(autoregressive moving average model-support vector machines,ARMA-SVM)组合模型实现能效的时间序列预测。最后以1.5 MW双馈异步风电机组为研究对象开展算例分析。结果表明该方法能够实现对能效异常状态的有效检测和预警,为风电机组的性能优化与故障分析提供了必要的决策参考。展开更多
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest in China(201303104 and 201503120)the earmarked fund for China Agriculture Research System(CARS-03-01-24)+1 种基金the Key Science and Technology Program of Shanxi Province,China(20140311008-3)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2015BAD23B04)
文摘Shortages and fluctuations in precipitation are influential limiting factors for the sustainable cultivation of rain-fed winter wheat on the Loess Plateau of China. Plastic film mulching is one of the most effective water management practices to improve soil moisture, and may be useful in the Loess Plateau for increasing soil water storage. A field experiment was conducted from July 2010 to June 2012 on the Loess Plateau to investigate the effects of mulching time and rates on soil water storage, evapotranspiration （ET）, water use efficiency （WUE）, and grain yield. Six treatments were conducted： （1） early mulching （starting 30 days after harvest） with whole mulching （EW）; （2） early mulching with half mulching （EH）; （3） early mulching with no mulching （EN）; （4） late mulching （starting 60 days after harvest） with whole mulching （LW）; （5） late mulching with half mulching （LH）; and （6） late mulching with no mulching （LN）. EW increased precipitation storage efficiency during the fallow periods of each season by 18.4 and 17.8%, respectively. EW improved soil water storage from 60 days after harvest to the booting stage and also outperformed LN by 13.8 and 20.9% in each growing season. EW also improved spike number per ha by 13.8 and 20.9% and grain yield by 11.7 and 17.4% during both years compared to LN. However, EW decreased WUE compared with LN. The overall results of this study demonstrated that EW could be a productive and efficient practice to improve wheat yield on the Loess Plateau of China.
文摘对ANSI/ASHRAE/ASHE standard 170-2021《医疗设施通风》的主要修订内容进行了分析,包括:修改医用房间名称,将有较高设计要求的房间与其他房间分开并提出细化指标;增加值班状态,为医疗建筑节能运行提供方法依据;进一步明确各类医疗用房排风过滤效率。此外,对ASHRAE 170发展趋势进行了简要介绍,对未来发展进行了展望,以期为我国医疗建筑相关标准规范的制订/修订提供参考。
文摘为提高风电机组系统的运行效率和稳定性,提出一种基于数据驱动的风电机组能效状态分析方法,实现对机组异常状态的高效检测与预警。首先从损耗与效率的角度出发,开展各因素对机组能效的影响分析,考虑到系统各部件能量损失主要体现在热量方面,因此以温度参数为依据,建立基于能量流的能效状态指标体系。然后利用风电机组数据采集与监视控制(supervisory control and data acquisition,SCADA)系统采集数据,确定各参数基准区间,构建指标偏离度矩阵,利用改进的鲸鱼算法(improved whale optimization algorithm,IWOA)优化支持向量机,实现对能效异常状态的检测。同时引入能效异常指数来表征机组能效变化情况,利用自回归滑动平均模型-支持向量机(autoregressive moving average model-support vector machines,ARMA-SVM)组合模型实现能效的时间序列预测。最后以1.5 MW双馈异步风电机组为研究对象开展算例分析。结果表明该方法能够实现对能效异常状态的有效检测和预警,为风电机组的性能优化与故障分析提供了必要的决策参考。
