The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofrefo...The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofreformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis-charge and discharge process are comprehensively analyzed according to the experimental data.It was foundthat the channel would be widened as the river slope or discharge increased and grain size decreased.If theangle-of-inflow was not zero,under certain conditions of grain size and discharge,a most suitable slope exist-ed,for which the river would develop into a pattem of meandering.Different discharge process would imposeon the change of river morphology,even caused transformation of channel patterns.Diversity in the capacity ofshaping rivers of different discharges especially the flood duration cast a light on the change of channel pattern.展开更多
CeO2-promoted Ni/Al2O3-ZrO2 （Ni/Al2O3-ZrO2-CeO2） catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared s...CeO2-promoted Ni/Al2O3-ZrO2 （Ni/Al2O3-ZrO2-CeO2） catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy （IR）, thermal gravimetric analysis （TGA）, microscopic analysis, X-ray diffraction （XRD） and temperature-programmed reduction （TPR）. The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports.展开更多
China＇s complex and twisted journey of SOE reform over the past four decades is an unprecedented transformation in its history and is at the center stage of its economic reforms. Over the past four decades, SOEs tran...China＇s complex and twisted journey of SOE reform over the past four decades is an unprecedented transformation in its history and is at the center stage of its economic reforms. Over the past four decades, SOEs transitioned from being affiliates of a planned economy to ＂new SOEs＂ as modern enterprises under the market economic system. This journey can be roughly divided into the following four stages： the reform to expand SOE autonomy during 1978-1993, the reform to create a modern enterprise system during 1993- 2003, the reform to create a new system for the administration of state assets during 2003- 2013, and the new era of classified SOE reform since 2013. After the four stages, China＇s SOE reform has made tremendous achievements, particularly since the 18th CPC National Congress. V~th policy readiness for SOE reform in the new era, reform should be carried out in a comprehensive and systematic manner for different types of SOEs in the future.展开更多
Decreasing supplies of high quality crude oil and increasing demand for high quality distillates have motivated the interest in converting natural gas to liquid fuels, especially with the present boom in natural gas p...Decreasing supplies of high quality crude oil and increasing demand for high quality distillates have motivated the interest in converting natural gas to liquid fuels, especially with the present boom in natural gas proven reserves. Nevertheless, one major issue is the curtailment of costs incurred in producing synthesis gas from natural gas, which account for approximately 60% of the costs used in producing liquid fuels. While there are three main routes to convert natural gas to syngas: steam reforming (SMR), partial Oxidation (POX) and auto-thermal reforming (ATR). Significant new developments and improvements in these technologies, established innovative processes to minimize greenhouse gases emission, minimize energy consumption, enhance syngas processes, adjust the desired H<sub>2</sub>/CO ratio and change the baseline economics. This article reviews the state of the art for the reforming of natural gas to synthesis gas taking into consideration all the new innovations in both processes and catalysis.展开更多
基金Supported by National Key Basic Research and Development Program(973 Program)(2003CB415205)the National Natural Science Foundation of China(50479036)
文摘The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofreformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis-charge and discharge process are comprehensively analyzed according to the experimental data.It was foundthat the channel would be widened as the river slope or discharge increased and grain size decreased.If theangle-of-inflow was not zero,under certain conditions of grain size and discharge,a most suitable slope exist-ed,for which the river would develop into a pattem of meandering.Different discharge process would imposeon the change of river morphology,even caused transformation of channel patterns.Diversity in the capacity ofshaping rivers of different discharges especially the flood duration cast a light on the change of channel pattern.
基金supported by the National Natural Science Foundation of China (NO. 20976013, 21006057)
文摘CeO2-promoted Ni/Al2O3-ZrO2 （Ni/Al2O3-ZrO2-CeO2） catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy （IR）, thermal gravimetric analysis （TGA）, microscopic analysis, X-ray diffraction （XRD） and temperature-programmed reduction （TPR）. The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports.
基金＇ From the two dimensions of modem property ownership system and market-based management system, ＇haew SOEs＂ can be defined as SOEs with modem property ownership systems （characterized by equity diversification and standard corporate governance） and market-based management system （characterized by independent operation, decision-making and management）. See ＂Pre ＇hminary Study on New SOEs Phenomenon＂, China Industrial Economics, Vol.6 2005 by Jin Bei and Huang Qunhui.
文摘China＇s complex and twisted journey of SOE reform over the past four decades is an unprecedented transformation in its history and is at the center stage of its economic reforms. Over the past four decades, SOEs transitioned from being affiliates of a planned economy to ＂new SOEs＂ as modern enterprises under the market economic system. This journey can be roughly divided into the following four stages： the reform to expand SOE autonomy during 1978-1993, the reform to create a modern enterprise system during 1993- 2003, the reform to create a new system for the administration of state assets during 2003- 2013, and the new era of classified SOE reform since 2013. After the four stages, China＇s SOE reform has made tremendous achievements, particularly since the 18th CPC National Congress. V~th policy readiness for SOE reform in the new era, reform should be carried out in a comprehensive and systematic manner for different types of SOEs in the future.
文摘Decreasing supplies of high quality crude oil and increasing demand for high quality distillates have motivated the interest in converting natural gas to liquid fuels, especially with the present boom in natural gas proven reserves. Nevertheless, one major issue is the curtailment of costs incurred in producing synthesis gas from natural gas, which account for approximately 60% of the costs used in producing liquid fuels. While there are three main routes to convert natural gas to syngas: steam reforming (SMR), partial Oxidation (POX) and auto-thermal reforming (ATR). Significant new developments and improvements in these technologies, established innovative processes to minimize greenhouse gases emission, minimize energy consumption, enhance syngas processes, adjust the desired H<sub>2</sub>/CO ratio and change the baseline economics. This article reviews the state of the art for the reforming of natural gas to synthesis gas taking into consideration all the new innovations in both processes and catalysis.
