A robust H∞ approach to filtering for a class of uncertain linear systems with time-delayed measurement is investigated. The parameter uncertainties are described by real time-varying norm-bounded form. A methodology...A robust H∞ approach to filtering for a class of uncertain linear systems with time-delayed measurement is investigated. The parameter uncertainties are described by real time-varying norm-bounded form. A methodology is developed for designing linear filters such that the filtering process remains robustly stable and the transfer function from the disturbance inputs to error state outputs meets the prescribed H∞-norm upper-bound constraints. The filter can be obtained and parameterized by solving two Riccati equations based on the lemma of robust stability for control system with delay. Simulation example proves the method to be effective and feasible.展开更多
Synthesizing epichlorohydrin(ECH) from dichloropropanol(DCP) is a complicated reaction due to the partial decomposition of ECH under harsh conditions. A microchemical system can provide a feasible platform for improvi...Synthesizing epichlorohydrin(ECH) from dichloropropanol(DCP) is a complicated reaction due to the partial decomposition of ECH under harsh conditions. A microchemical system can provide a feasible platform for improving this process by conducting a separation once full conversion has been achieved. In this work, referring to a common DCP feed used in industry, the reaction performance of mixed DCP isomers with Na OH in the microchemical system on various time scales was investigated. The operating window for achieving high conversion and selectivity was on a time scale of seconds, while the side reactions normally occurred on a time scale of minutes. Plenty of Cl-ions together with a high temperature were proved to be critical factors for ECH hydrolysis.A kinetic study of alkaline mediated ECH hydrolysis was performed and the requirements for an improved ECH synthesis were proposed by combining quantitative analysis using a simpli fied reaction model with experimental results on the time scale of minutes. Compared with the conventional distillation process, this new strategy for ECH synthesis exploited microchemical system and decoupled the reaction and separation with potentials of higher productivity and better reliability in scaling up.展开更多
There is a consensus that sediment delivery ratio in the Chinese Loess Plateau is close to 1at the inter-annual timescale. However, little information is available about the sediment delivery at finer timescales. We e...There is a consensus that sediment delivery ratio in the Chinese Loess Plateau is close to 1at the inter-annual timescale. However, little information is available about the sediment delivery at finer timescales. We evaluated the sediment delivery from plots to watersheds at the event or intra-annual, annual, and inter-annual timescales within the Wudinghe river basin, a 30,261 km2 basin in the Loess Plateau. We calculated the ratio of sediment output to sediment input and presented the temporal change of the channel morphology to determine whether sediment deposition occurs.Although a single flood event frequently has a sediment yield exceeding 10,000 t km-2, sediment deposition rarely occurs except during some small runoff events(sediment yield < 5000 t km-2) or dry years(sediment yield < 10,000 t km-2) when moving from slopes up to the main channels of the Wudinghe River. This observation suggests a sediment delivery ratio close to 1 even at the event or intra-annual and the annual timescales, but not necessarily at the interannual timescale. Such a high sediment delivery ratio can be related to hyper-concentrated flows, which have very strong sediment transport capacity even at low flow strength. Because hyper-concentrated flows are well-developed in the whole Loess Plateau, a sediment delivery ratio close to 1 below the interannual timescale possibly remains true for other rivers in the Loess Plateau.展开更多
High temperature treatment of tungsten alloy of W-5wt.% TM （transition metals, TM = Ni, Fe, Cu, Co） nanopowder was run under different temperatures to cover the oxidation rate at different temperatures. The correlat...High temperature treatment of tungsten alloy of W-5wt.% TM （transition metals, TM = Ni, Fe, Cu, Co） nanopowder was run under different temperatures to cover the oxidation rate at different temperatures. The correlation was developed for certain temperatures to find an equation for the relation between time and weight. The thermal treatment was done for different quantities at certain times. The proposed equation studies the correlation between temperature, time, and weight. For each temperature, a number of points were recorded from the measured oxidation curve. The shape of the curves is well-represented in this paper. The final results will present the highest temperature, the maximum weight, and the maximum time for full oxidation at high and low temperatures.展开更多
This paper proposes a precise localization algorithm for a quickly moving mobile robot.In order to localize a mobile robot with active beacon sensors,a relatively long time is needed,since the distance to the beacon i...This paper proposes a precise localization algorithm for a quickly moving mobile robot.In order to localize a mobile robot with active beacon sensors,a relatively long time is needed,since the distance to the beacon is measured by transmitting time of the ultrasonic signal.The measurement time does not cause a high error rate when the mobile robot moves slowly.However,with an increase of the mobile robot’s speed,the localization error becomes too high to use for accurate mobile robot navigation.Therefore,in this research into high speed mobile robot operations,instead of using two active beacons for localization,an active beacon and dual compass are utilized to localize the mobile robot.This new approach resolves the high localization error caused by the speed of the mobile robot.The performance of the precise localization algorithm is verified by comparing it to the conventional method through real-world experiments.展开更多
基金in part by the National Natural Science Foundation under Grrant 69804007,863/CIMS High Technology Foundation 511--845-008 and Science and Technology Program of Shanghai(99QD14012)
文摘A robust H∞ approach to filtering for a class of uncertain linear systems with time-delayed measurement is investigated. The parameter uncertainties are described by real time-varying norm-bounded form. A methodology is developed for designing linear filters such that the filtering process remains robustly stable and the transfer function from the disturbance inputs to error state outputs meets the prescribed H∞-norm upper-bound constraints. The filter can be obtained and parameterized by solving two Riccati equations based on the lemma of robust stability for control system with delay. Simulation example proves the method to be effective and feasible.
基金Supported by the National Natural Science Foundation of China(21036002,21176136)the National Science and Technology Support Program of China(2011BAC06B01)
文摘Synthesizing epichlorohydrin(ECH) from dichloropropanol(DCP) is a complicated reaction due to the partial decomposition of ECH under harsh conditions. A microchemical system can provide a feasible platform for improving this process by conducting a separation once full conversion has been achieved. In this work, referring to a common DCP feed used in industry, the reaction performance of mixed DCP isomers with Na OH in the microchemical system on various time scales was investigated. The operating window for achieving high conversion and selectivity was on a time scale of seconds, while the side reactions normally occurred on a time scale of minutes. Plenty of Cl-ions together with a high temperature were proved to be critical factors for ECH hydrolysis.A kinetic study of alkaline mediated ECH hydrolysis was performed and the requirements for an improved ECH synthesis were proposed by combining quantitative analysis using a simpli fied reaction model with experimental results on the time scale of minutes. Compared with the conventional distillation process, this new strategy for ECH synthesis exploited microchemical system and decoupled the reaction and separation with potentials of higher productivity and better reliability in scaling up.
基金funded by National Natural Science Foundation of China (Grant Nos. 41230746, 41271306)the National Key Technology Research and Development Program (Grant No. 2012BAC09B03)the Open-fund Project of Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention (Grant No. JXSB201301)
文摘There is a consensus that sediment delivery ratio in the Chinese Loess Plateau is close to 1at the inter-annual timescale. However, little information is available about the sediment delivery at finer timescales. We evaluated the sediment delivery from plots to watersheds at the event or intra-annual, annual, and inter-annual timescales within the Wudinghe river basin, a 30,261 km2 basin in the Loess Plateau. We calculated the ratio of sediment output to sediment input and presented the temporal change of the channel morphology to determine whether sediment deposition occurs.Although a single flood event frequently has a sediment yield exceeding 10,000 t km-2, sediment deposition rarely occurs except during some small runoff events(sediment yield < 5000 t km-2) or dry years(sediment yield < 10,000 t km-2) when moving from slopes up to the main channels of the Wudinghe River. This observation suggests a sediment delivery ratio close to 1 even at the event or intra-annual and the annual timescales, but not necessarily at the interannual timescale. Such a high sediment delivery ratio can be related to hyper-concentrated flows, which have very strong sediment transport capacity even at low flow strength. Because hyper-concentrated flows are well-developed in the whole Loess Plateau, a sediment delivery ratio close to 1 below the interannual timescale possibly remains true for other rivers in the Loess Plateau.
文摘High temperature treatment of tungsten alloy of W-5wt.% TM （transition metals, TM = Ni, Fe, Cu, Co） nanopowder was run under different temperatures to cover the oxidation rate at different temperatures. The correlation was developed for certain temperatures to find an equation for the relation between time and weight. The thermal treatment was done for different quantities at certain times. The proposed equation studies the correlation between temperature, time, and weight. For each temperature, a number of points were recorded from the measured oxidation curve. The shape of the curves is well-represented in this paper. The final results will present the highest temperature, the maximum weight, and the maximum time for full oxidation at high and low temperatures.
基金supported by the MKE(The Ministry of Knowledge Economy),Korea,under the ITRC(Information Technology Research Center)support program supervised by the NIPA(National IT Industry Promotion Agency)(NIPA-2011-C1090-1121-0010)
文摘This paper proposes a precise localization algorithm for a quickly moving mobile robot.In order to localize a mobile robot with active beacon sensors,a relatively long time is needed,since the distance to the beacon is measured by transmitting time of the ultrasonic signal.The measurement time does not cause a high error rate when the mobile robot moves slowly.However,with an increase of the mobile robot’s speed,the localization error becomes too high to use for accurate mobile robot navigation.Therefore,in this research into high speed mobile robot operations,instead of using two active beacons for localization,an active beacon and dual compass are utilized to localize the mobile robot.This new approach resolves the high localization error caused by the speed of the mobile robot.The performance of the precise localization algorithm is verified by comparing it to the conventional method through real-world experiments.
