Soft rocks are a critical geomaterial presenting several kinds of problems.They present undesirable behaviors such as low strength,disaggregation,high plasticity,slaking,weathering and other characteristics.These beha...Soft rocks are a critical geomaterial presenting several kinds of problems.They present undesirable behaviors such as low strength,disaggregation,high plasticity,slaking,weathering and other characteristics.These behaviors prevent their utilization or tend to avoid sites dominated by soft rocks for important engineer-展开更多
Within the seven years’ period from 1987 to 1994. the total installed capacity of China’s electric power industry doubled from 100 GW to 200 GW. This high rate of growth has imposed new and more stringent requiremen...Within the seven years’ period from 1987 to 1994. the total installed capacity of China’s electric power industry doubled from 100 GW to 200 GW. This high rate of growth has imposed new and more stringent requirements on all the branches in the展开更多
To advance the field of science and technology,we need to revitalize the development of science and technology through innovation.The development of science and technology has many beneficial implications on the revit...To advance the field of science and technology,we need to revitalize the development of science and technology through innovation.The development of science and technology has many beneficial implications on the revitalization of the country.For this reason,universities in China should give full attention to their role as the main propeller of science and technology.“Streamlining administration,delegating powers,improving regulation,and strengthening services”is a policy issued by the Chinese government for the management of science and technology funds in colleges and universities.Based on the policy of“streamlining administration,delegating powers,improving regulation,and strengthening services,”colleges and universities must optimize the management of science and technology funds for their efficient use.In this paper,we analyzed the importance of the policy and put forward an effective management strategy,aiming to improve the management of science and technology funds in colleges and universities.展开更多
Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power ...Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.展开更多
Soft matter, as first proposed by de Gennes in 1991, describes a broad range of molecular systems exhibiting a large response to small foreign stimuli. Typically, it includes colloidal particles, amphiphiles, liquid c...Soft matter, as first proposed by de Gennes in 1991, describes a broad range of molecular systems exhibiting a large response to small foreign stimuli. Typically, it includes colloidal particles, amphiphiles, liquid crystals, polymers and others. The term ＂soft＂ originates from the common macroscopic properties of these systems and differentiates them from conventional ＂hard＂ materials. Over the past decades, the field of ＂soft matter＂ has progressed tremendously. Today, it is a truly multidisciplinary research endeavor bridging physics with chemistry and life science. There are many research activities all over the world that are solely devoted to the field of soft matter. In turn, the in-depth understanding of soft matter has promoted our sci- ence and technology and helped shaping our civilization as it is now.展开更多
火力发电企业作为我国能源结构的重要组成部分,长期以来是我国碳排放的主要来源,在我国和全球加速推动低碳经济发展的宏观环境下,火电企业积极响应国家“能耗双控”向“碳排放双控”转变的战略部署。在此背景下,精确计量燃煤电厂的碳排...火力发电企业作为我国能源结构的重要组成部分,长期以来是我国碳排放的主要来源,在我国和全球加速推动低碳经济发展的宏观环境下,火电企业积极响应国家“能耗双控”向“碳排放双控”转变的战略部署。在此背景下,精确计量燃煤电厂的碳排放量变得至关重要。在燃煤电厂碳计量中,烟气流量影响燃煤发电中在线监测法的精度,而燃煤消耗量、燃煤元素碳含量以及飞灰碳含量共同决定核算法的可靠性。目前,大多数燃煤发电企业只对流量和燃煤消耗量进行实时监测,在现场恶劣的环境中对燃煤元素碳含量以及飞灰碳含量进行短周期、高频次的直接监测需要花费较大的人力以及物力,流量监测设备也易受烟道环境影响。而软测量技术以其高效和低成本的特点,可为传统碳排放计量过程中关键参数的监测提供一种替代方法。鉴于此,首先阐述了软测量模型的建立过程,包含数据预处理、辅助变量选择、软测量模型建立以及模型校正。数据预处理能够确保数据质量,提高建模效率;辅助变量选择是从大量潜在的变量中筛选出对目标变量的辅助变量,进一步提高建模效率;软测量模型建立主要是基于机理建模和数据驱动建模,是实现目标变量预测的核心;模型校正通过实际的离线或在线数据,对模型进行进一步优化,提高模型的预测精度。其次,针对碳计量相关参数,分析了烟气流量、燃煤消耗量、燃煤元素碳含量和飞灰碳含量监测存在的问题,论述了软测量技术在上述碳计量关键参数的国内外研究进展和应用,评估了机理建模和数据驱动建模技术的有效性、准确性和实用性。其中,机理分析建模主要基于电厂锅炉进出口的能量平衡以及烟风质量守恒等原理,有着确定的数学物理关系式,具有高度可解释性和稳定性,但是建模过程复杂,预测精度较低;数据驱动建模主要是利用各种机器学习方法,基于电厂分布式控制系统(Distributed control system,DCS)丰富的运行数据,对碳计量关键参数进行“黑箱建模”,克服了机理分析建模复杂的过程分析,精度相对较高,但是建模过程不明确,且模型对于不同机组的泛化能力较差。最后,对于软测量技术在碳排放计量领域的发展应用进行了总结与展望。对电厂各参数之间的时序结构、电厂自身计算能力的限制以及机理分析融合数据驱动方法的发展提出相关建议,并对国外二氧化碳预测性排放系统结合软测量技术在国内外燃煤电厂的应用进行展望。展开更多
文摘Soft rocks are a critical geomaterial presenting several kinds of problems.They present undesirable behaviors such as low strength,disaggregation,high plasticity,slaking,weathering and other characteristics.These behaviors prevent their utilization or tend to avoid sites dominated by soft rocks for important engineer-
文摘Within the seven years’ period from 1987 to 1994. the total installed capacity of China’s electric power industry doubled from 100 GW to 200 GW. This high rate of growth has imposed new and more stringent requirements on all the branches in the
文摘To advance the field of science and technology,we need to revitalize the development of science and technology through innovation.The development of science and technology has many beneficial implications on the revitalization of the country.For this reason,universities in China should give full attention to their role as the main propeller of science and technology.“Streamlining administration,delegating powers,improving regulation,and strengthening services”is a policy issued by the Chinese government for the management of science and technology funds in colleges and universities.Based on the policy of“streamlining administration,delegating powers,improving regulation,and strengthening services,”colleges and universities must optimize the management of science and technology funds for their efficient use.In this paper,we analyzed the importance of the policy and put forward an effective management strategy,aiming to improve the management of science and technology funds in colleges and universities.
基金supported by the National Natural Science Founda-tion under Grant No. 50771089 and No.10802029
文摘Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.
文摘Soft matter, as first proposed by de Gennes in 1991, describes a broad range of molecular systems exhibiting a large response to small foreign stimuli. Typically, it includes colloidal particles, amphiphiles, liquid crystals, polymers and others. The term ＂soft＂ originates from the common macroscopic properties of these systems and differentiates them from conventional ＂hard＂ materials. Over the past decades, the field of ＂soft matter＂ has progressed tremendously. Today, it is a truly multidisciplinary research endeavor bridging physics with chemistry and life science. There are many research activities all over the world that are solely devoted to the field of soft matter. In turn, the in-depth understanding of soft matter has promoted our sci- ence and technology and helped shaping our civilization as it is now.
文摘火力发电企业作为我国能源结构的重要组成部分,长期以来是我国碳排放的主要来源,在我国和全球加速推动低碳经济发展的宏观环境下,火电企业积极响应国家“能耗双控”向“碳排放双控”转变的战略部署。在此背景下,精确计量燃煤电厂的碳排放量变得至关重要。在燃煤电厂碳计量中,烟气流量影响燃煤发电中在线监测法的精度,而燃煤消耗量、燃煤元素碳含量以及飞灰碳含量共同决定核算法的可靠性。目前,大多数燃煤发电企业只对流量和燃煤消耗量进行实时监测,在现场恶劣的环境中对燃煤元素碳含量以及飞灰碳含量进行短周期、高频次的直接监测需要花费较大的人力以及物力,流量监测设备也易受烟道环境影响。而软测量技术以其高效和低成本的特点,可为传统碳排放计量过程中关键参数的监测提供一种替代方法。鉴于此,首先阐述了软测量模型的建立过程,包含数据预处理、辅助变量选择、软测量模型建立以及模型校正。数据预处理能够确保数据质量,提高建模效率;辅助变量选择是从大量潜在的变量中筛选出对目标变量的辅助变量,进一步提高建模效率;软测量模型建立主要是基于机理建模和数据驱动建模,是实现目标变量预测的核心;模型校正通过实际的离线或在线数据,对模型进行进一步优化,提高模型的预测精度。其次,针对碳计量相关参数,分析了烟气流量、燃煤消耗量、燃煤元素碳含量和飞灰碳含量监测存在的问题,论述了软测量技术在上述碳计量关键参数的国内外研究进展和应用,评估了机理建模和数据驱动建模技术的有效性、准确性和实用性。其中,机理分析建模主要基于电厂锅炉进出口的能量平衡以及烟风质量守恒等原理,有着确定的数学物理关系式,具有高度可解释性和稳定性,但是建模过程复杂,预测精度较低;数据驱动建模主要是利用各种机器学习方法,基于电厂分布式控制系统(Distributed control system,DCS)丰富的运行数据,对碳计量关键参数进行“黑箱建模”,克服了机理分析建模复杂的过程分析,精度相对较高,但是建模过程不明确,且模型对于不同机组的泛化能力较差。最后,对于软测量技术在碳排放计量领域的发展应用进行了总结与展望。对电厂各参数之间的时序结构、电厂自身计算能力的限制以及机理分析融合数据驱动方法的发展提出相关建议,并对国外二氧化碳预测性排放系统结合软测量技术在国内外燃煤电厂的应用进行展望。
