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我国“重点制”教育的弊端及改革思路
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作者 游永恒 《广西教育》 2006年第07A期10-10,共1页
实践证明“重点制”这种模式下的教育行为无法真正实现我们的教育目的;远离教育公平的目标;引发学生各种心理问题;造成道德教育的失落;导致学校之间的恶性竞争。可以说我们现在的许多教育问题都与我们的教育“重点制”这种制度设计... 实践证明“重点制”这种模式下的教育行为无法真正实现我们的教育目的;远离教育公平的目标;引发学生各种心理问题;造成道德教育的失落;导致学校之间的恶性竞争。可以说我们现在的许多教育问题都与我们的教育“重点制”这种制度设计密切相关。因此,必须重新认识和深刻反省我们的教育“重点制”,对之进行改革。 展开更多
关键词 教育目的 教育行为 教育公平 基础教育 道德教育 恶性竞争 改革思路 “重点制”教育 中国
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示范校要体现时代的精神
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作者 黄成松 《中小学管理》 北大核心 2002年第4期16-17,共2页
所谓示范高中的“示范”,在本质上反映了一种办学上的新变化,有着相当明晰的时代内涵。
关键词 示范校 时代精神 示范高中 “重点制”
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Recent developments on applications of sequential loop closing and diagonal dominance control schemes to industrial multivariable system 被引量:4
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作者 A.H.Mazinan M.F.Kazemi 《Journal of Central South University》 SCIE EI CAS 2013年第12期3401-3420,共20页
With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case,... With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case, at first, each subsystem is distinctively represented by its model, since the outcomes point out that the chosen models have the same behavior as corresponding ones. Then, the industrial multivariable system and its presentation are achieved in line with the integration of these subsystems, since the interaction between them can not actually be ignored. To analyze the interaction presented, the Gershgorin bands need to be acquired, where the results are used to modify the system parameters to appropriate values. Subsequently, in the view of modeling results, the control concept in two different techniques including sequential loop closing control(SLCC) scheme and diagonal dominance control(DDC) schemes is proposed to implement on the system through the Profibus network, as long as the OPC(OLE for process control) server is utilized to communicate between the control schemes presented and the multivariable system. The real test scenarios are carried out and the corresponding outcomes in their present forms are acquired. In the same way, the proposed control schemes results are compared with each other, where the real consequences verify the validity of them in the field of the presented industrial multivariable system control. 展开更多
关键词 multivariable system diagonal dominance control sequential loop closing control Profibus network OPC server orifice relation interaction analysis Gershogerin bands non-minimum phase system
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Effects of Promoters on the Ignition Process over NiO/Al_2O_3 Catalyst for Autothermal Reforming of Methane to Hydrogen 被引量:1
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作者 Cai Xiulan Li Guangyan Lin Weiming 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第3期56-62,共7页
The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. ... The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. The ignition process on the catalysts for the autothermal reforming of methane to hydrogen was investigated and the surface properties of the catalysts were characterized by XPS. The results showed that the Ni/Al2O3 catalyst could not ignite the process of autothermal reforming of methane to hydrogen. However, the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature(650 ℃) with the conversion of methane reaching 76%. The result of XPS analysis indicated that the promoters could change the binding energy(BE) of Ni2p3/2 obviously. The species of Cu in the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst comprised Cu2 O and Cu2+. The formation of ZrO2-CeO2 solid solution and a large amount of Cu2 O might be the reason leading to good oxygen storage capacity and mobility of lattice oxygen of the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst, which could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature. 展开更多
关键词 METHANE autothermal reforming hydrogen production ignition process
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Effect of Electrochemical Treatment in Aqueous Ammonium Bicarbonate on Surface Properties of PAN-based Carbon Fibers 被引量:3
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作者 曹海琳 黄玉东 +1 位作者 张志谦 孙举涛 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第2期168-173,共6页
The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microsc... The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased. 展开更多
关键词 PAN-based carbon fiber electrochemical treatment surface properties aqueous ammonium bicarbonate
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Model predictive flux control of permanent magnet synchronous motor driven by three-level inverter based on fine-division strategy 被引量:1
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作者 MIAO Zhongcui LI Haiyuan +1 位作者 HE Yangyang WANG Yunkun 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2022年第4期439-450,共12页
Aiming at the difficulty of setting the weight coefficient in the value function of model predictive torque control(MPTC)for permanent magnet synchronous motor(PMSM)driven by three-level inverter,a fine-division model... Aiming at the difficulty of setting the weight coefficient in the value function of model predictive torque control(MPTC)for permanent magnet synchronous motor(PMSM)driven by three-level inverter,a fine-division model predictive flux control(MPFC)method is proposed.First,establish a mathematical model between the motor torque and the stator flux linkage according to the mathematical equations of PMSM.Thus,the control of the motor torque and stator flux linkage in the MPTC is transformed into the control of a single stator flux linkage vector,omitting the cumbersome weight setting process in the traditional MPTC.The midpoint potential control strategy is proposed,which uses the characteristics of redundant small vectors to balance the midpoint potential.After that,a fine-division strategy is proposed,which effectively reduces the number of candidate vectors and the computational burden of the system.Finally,the proposed MPFC is compared with MPTC by simulation.The results show that the proposed fine-division MPFC effectively reduces the system calculation,and has the advantages of simple principle and better dynamic and steady-state control performance.The feasibility of the control strategy is verified. 展开更多
关键词 permanent magnet synchronous motor(PMSM) three-level inverter model predictive flux control(MPFC) weight coefficient midpoint potential
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Industrialization prospects for hydrogen production by coal gasification in supercritical water and novel thermodynamic cycle power generation system with no pollution emission 被引量:10
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作者 GUO LieJin JIN Hui +2 位作者 GE ZhiWei LU YouJun CAO ChangQing 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第12期1989-2002,共14页
Energy conversion and utilization, particularly carbon-based fuel burning in air phase, have caused great environmental pollution and serious problems to society. The reactions in water phase may have the potential to... Energy conversion and utilization, particularly carbon-based fuel burning in air phase, have caused great environmental pollution and serious problems to society. The reactions in water phase may have the potential to realize clean and efficient energy conversion and utilization. Coal gasification in supercritical water is a typical carbon-based fuel conversion process in water phase, and it takes the advantages of the unique chemical and physical properties of supercritical water to convert organic matter in coal to H2 and CO2. N, S, P, Hg and other elements are deposited as inorganic salts to avoid pollution emission. The State Key Laboratory of Multiphase Flow in Power Engineering has obtained extensive experimental and theoretical results based on coal gasification in supercritical water. Supercritical water fluidized bed reactor was developed for coal gasification and seven kinds of typical feedstock were selected. The hydrogen yield covers from 0.67 to 1.74 Nm3/kg and the carbon gasification efficiency is no less than 97%. This technology has a bright future in industrialization not only in electricity generation but also in hydrogen production and high value-added chemicals. Given the gas yield obtained in laboratory-scale unit, the hydrogen production cost is U.S.$ 0.111 Nm3 when the throughput capacity is 2000 t/d. A novel thermodynamic cycle power generation system based on coal gasification in supercritical water was proposed with the obvious advantages of high coal-electricity conversion efficiency and zero pollutant emission. The cost of U.S.$ 3.69 billion for desulfuration, denitration and dust removal in China in 2013 would have been saved with this technology. Five kinds of heat supply methods are analyzed and the rates of return of investment are roughly estimated. An integrated cooperative innovation center called a new type of high-efficient coal gasification technology and its large-scale utilization was founded to enhance the industrialization of the technology vigorously. 展开更多
关键词 industrialization prospects hydrogen production supercritical water gasification power generation zero emission
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A miniature liquid helium temperature JT cryocooler for space application 被引量:16
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作者 QUAN Jia ZHOU ZhenJun +3 位作者 LIU YanJie LI JianGuo MA YueXue LIANG JingTao 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第11期2236-2240,共5页
Along with the development of space science and technology,miniature liquid helium temperature long life cryocooler is a focus subject in cryogenic study.Since it is the precondition of space detection researches,inst... Along with the development of space science and technology,miniature liquid helium temperature long life cryocooler is a focus subject in cryogenic study.Since it is the precondition of space detection researches,institutions of space in many countries do the research on it.In this article,we designed a compound cooling system.A three-stage high frequency thermal coupled pulse tube cryocooler was used to precool a Joule-Thomson(JT)cryocooler.This system has no moving parts at low temperatures and is hence suitable for space operation.Liquid helium temperature was successfully achieved in both open loop and closed cycle experiments.In the closed cycle experiment,when 473 W electric power was inputted,the cooling system reached a no-load temperature of 4.4 K,and a cooling capacity of 11.6 mW was provided at 4.54 K.It is the first miniature liquid helium temperature JT cryocooler in China and the research achievement paves a way for the space application of ultra-long wave infrared detection and THz technologies. 展开更多
关键词 liquid helium temperature JT cryocooler space application
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A Brief Introduction of the Achievements of Key Project Image-based Modeling and Rendering for Virtual Reality Applications
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作者 Jiaoying Shi Zhanyi Hu +1 位作者 Enhua Wu Qunsheng Peng 《Science Foundation in China》 CAS 2006年第2期60-62,共3页
1. Background The virtual reality (VR) technology is now at the frontier of modern information science. VR is based on computer graphics, computer vision, and other fresh air topics in today's computer technology.... 1. Background The virtual reality (VR) technology is now at the frontier of modern information science. VR is based on computer graphics, computer vision, and other fresh air topics in today's computer technology. Nowadays the VR technology has been applied successfully in variety of fields such as military simulation, industry, medical training and visualization, environment protection and entertainment. 展开更多
关键词 Virtual reality Image-based modeling and rendering
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