During horizontal well drilling,the interaction between drilling fluid and cuttings entering the annulus generates diverse flow patterns.These solid-liquid two-phase flow patterns must be accurately predicted to optim...During horizontal well drilling,the interaction between drilling fluid and cuttings entering the annulus generates diverse flow patterns.These solid-liquid two-phase flow patterns must be accurately predicted to optimize the determination of hydraulic parameters and improve the efficiency of cuttings transport.Accordingly,this study identified flow patterns and conducted transition experiments under different inclination angles using a visualized wellbore annulus apparatus(120 mm outer diameter/73 mm inner diameter).Through direct visual observations,four primary flow patterns were systematically classified on the basis of the solid-liquid two-phase flow behaviors identified in the experiments:stable bed(SB),sand wave(SW),sand dune(SD),and bed load(BL)flows.The experimental data were then used to construct flow pattern maps with solid/liquid phases as axes,after which the transition boundaries between different flow patterns were established.The morphological characteristics and transition mechanisms of SB,SW,SD,and BL flows were systematically analyzed to develop three predictive models of the fluid dynamics principles governing these flow patterns’transitions:(1)A transition boundary model of SB and SW flows was established using Kelvin-Helmholtz stability,for which a stability analysis of solid-liquid two-phase flow in deviated and horizontal annuli was carried out.(2)A transition boundary model of SW and SD flows was constructed through an analysis of the geometric features of sand waves in the annuli,with the critical ratio of the average height of a cuttings bed to its height after erosion being 0.45.(3)A traditional critical velocity model was refined by adjusting the von Karman constant to account for the effect of solid volume concentration,yielding a boundary model for the transition of SW or SD flow into BL flow.All the models were experimentally validated.Finally,we integrated the models to develop a unified method for identifying and classifying the patterns typifying solid-liquid two-phase flow in deviated and horizontal annuli.展开更多
The role of authigenic clay growth in clay gouge is increasingly recognized as a key to understanding the mechanics of berittle faulting and fault zone processes,including creep and seismogenesis,and providing new ins...The role of authigenic clay growth in clay gouge is increasingly recognized as a key to understanding the mechanics of berittle faulting and fault zone processes,including creep and seismogenesis,and providing new insights into the ongoing debate about the frictional strength of brittle fault(Haines and van der Pluijm,2012).However,neither the conditions nor the processes which展开更多
Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered ＂concrete＂, ＂man-centered＂, and ＂ordinal＂; whil...Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered ＂concrete＂, ＂man-centered＂, and ＂ordinal＂; while the western one is believed to be ＂abstract＂, ＂object-centered＂, and ＂conversed＂. These are the decisive factors for the existence of the differences in language expressing. It is of great importance to study these differences and make some adjustments in terms of syntactic structure, semantic focus, and time order so as to achieve a natural rending.展开更多
Based on the characteristic of ‘one river one oasis’ in the arid areas, the Yerqiang River Basin, which is the largest irrigated area of Xinjiang, is taken as an example in this paper, and the regional water circula...Based on the characteristic of ‘one river one oasis’ in the arid areas, the Yerqiang River Basin, which is the largest irrigated area of Xinjiang, is taken as an example in this paper, and the regional water circulation pattern is investigated through the analysis of 60 groups of isotope data in the basin. From the phreatic evaporation data analysis of different soils, we study the law of phreatic evaporation, complete the research of the main consumption path of the groundwater, and improve the assessment precision of water resources. The transformation mount of regional water resources are predicted by calculation, which provides a scientific basis for water resources assessment and allocation in arid regions, and offers a new method for the study of regional water circulation patterns.展开更多
Abstract In periodic cellular structures, novel pattern transformations are triggered by a reversible elastic instability under the axial compression. Based on the deformation-triggered new pattern, periodic cellular ...Abstract In periodic cellular structures, novel pattern transformations are triggered by a reversible elastic instability under the axial compression. Based on the deformation-triggered new pattern, periodic cellular structures can achieve special mechanical properties. In this paper, the designed architecture materials which include elastomer matrixes containing empty holes or filled holes with hydrogel material are modeled and simulated to investigate the mechanical property of the periodic materials. By analyzing the relationship between nominal stress and nominal strain of periodic material, and the corresponding deformed patterns, the influence of geometry and shapes of the holes on the mechanical property of architecture material is studied in more details. We hope this study can provide future perspectives for the deformation-triggered periodic structures.展开更多
The year of 2000 is at the turn of the century as well as of the millennium. Themankind waves farewell to the 20th century as well as the second millenniumand welcomes the 21st century and the third millennium. At thi...The year of 2000 is at the turn of the century as well as of the millennium. Themankind waves farewell to the 20th century as well as the second millenniumand welcomes the 21st century and the third millennium. At this special juncture,looking closely at the future based on understanding which was obtained from re-viewing and summarizing the past and present world politics from historical andphilosophical standpoints, we can find that it has become an unavoidable subject onhow to regard the trend of the world pattern toward multi-polarization and respon-sibility adjustment arising from it.展开更多
In coping with the global financial crisis, all levels of the Chinese government and foreign trade firms have not only created new practices but have also changed their goal from transforming the growth pattern of for...In coping with the global financial crisis, all levels of the Chinese government and foreign trade firms have not only created new practices but have also changed their goal from transforming the growth pattern of foreign trade to transforming the development pattern of joreign trade. China＇s experience shows that economic instruments such as Net Barter Terms of Trade （NBTT） and the smile curve theory have limitations when it comes to interpreting foreign trade. If used improperly, scientific theories often lead to.fallacies. Transjbrming the development pattern of China＇s .foreign trade requires the following changes： national income distribution, foreign trade competition, market exploration, and resource utilization. We advise that competent authorities create a reasonable and operational system of assessment indicators.展开更多
The development of modern science and technology in China involved three transformations: from a traditional mindset to a modern one through the enlightenment of scientific thought, from the Anglo-Saxon pattern to the...The development of modern science and technology in China involved three transformations: from a traditional mindset to a modern one through the enlightenment of scientific thought, from the Anglo-Saxon pattern to the Soviet pattern in the process of instituting the Chinese system of science and technology, and from national defence to economics due to an awakening of technical economics after the ‘Cultural Revolution'. This paper surveys the political background of the second transformation. The idea of‘doing science for science's sake' never had a footing in China because the Chinese began to learn about modern science and technology only under the threat of colonists' gunboats. Developing science and technology has always been one of the means for China to cast off national humiliation and regain its status as a major country in the world. Compared with science and technology in other countries, Chinese science and technology were more susceptible to the international political environment and domestic political situation. It took about two decades, between the establishment of the Academia Sinica in 1928 and the inauguration of the Chinese Academy of Sciences in 1949, for China to form its system of science and technology. The system had three successive configurations because of the international competition among Japan, the US and the Soviet Union over China, and the domestic political contest between the Chinese Nationalist Party or Kuomintang(founded by Sun Yat-sen in 1912) and the Communist Party of China. China's science and technology system started by modelling itself on its counterparts in Europe and America. After undergoing a series of unconventional developments during the War of Resistance against Japanese Aggression(1931–1945) and the War of Liberation(1946–1949), the system transformed to the Soviet pattern after the establishment of the People's Republic of China.展开更多
Over the past 20 years, China has made spectacular achievements in economic growth as well as in thetransformation of economic growth pattern. Industrial structure is being updated, and technology is playing a more an...Over the past 20 years, China has made spectacular achievements in economic growth as well as in thetransformation of economic growth pattern. Industrial structure is being updated, and technology is playing a more andmore important role in economic development. The energy and resource consumption in many industries and enterprisesare reducing. However, we should realize that there are still many problems in changing the economic growth pattern,such as high input, high consumption, high discharge, inharmony, recycling difficulty, and low efficiency, which havegreatly impaired and restrict Chinese economic development. Therefore, the fundamental change of the economic growthpattern is inevitable. Based on the analysis on the status quo and the exploit of resources, this paper suggests that thetransformation from unsustainable to sustainable growth is the only choice in changing the economic growth pattern. Inaddition, the transformation should not completely rely on the fundamental effects of market mechanism. We should makefull use of the power of governments to speed up the transformation of economic system.展开更多
Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D ma...Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D map. The scheme of regional geochemical division includes non supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.展开更多
The BRICS （Brazil, Russia, India, China and South Africa） and other emerging economies have become a driving global force for the past twenty years. However, their growth patterns are obsolete, impeding the quality ...The BRICS （Brazil, Russia, India, China and South Africa） and other emerging economies have become a driving global force for the past twenty years. However, their growth patterns are obsolete, impeding the quality and competitiveness of their economic growth, while simultaneously threatening the sustainability of their economic convergence with developed nations. Transforming the domestic growth pattern-the solution to the middle-income trap-has therefore become a key priority for each of these economies. This paper presents a comparative analysis of how to transform the pattern of economic growth in BRICS and achieve sustainable economic convergence with a comparative analysis of the pattern of economic growth and problems among BRICS countries.展开更多
Using available data and necessary estimations, this paper provides a tentative picture of the balance sheet of China＇s sovereign account between 2000 and 2010. The main findings indicate that the net worth of China...Using available data and necessary estimations, this paper provides a tentative picture of the balance sheet of China＇s sovereign account between 2000 and 2010. The main findings indicate that the net worth of China＇s sovereign assets had been positive and increasing during the period under review. This implies that the Chinese government has sufficient sovereign assets to cover its sovereign liabilities, therefore the likelihood of a sovereign debt crisis in China is extremely low in the near term. Moreover, although China＇s leverage ratio （total liabilities/GDP） is far lower compared to advanced economies, it seems higher than that of other major emerging economies such as Brazil, Russia, and India （BRIC）. In fact, the leverage ratio has been increasing rapidly over recent years and requires special attention. In particular, according to sector-specific analysis, high corporate liability ratios （percentage to GDP） constitute a major concern of China＇s national balance sheet. In 2010, this liability ratio exceeded l OO percent, which exceeds the 90 percent level observed in OECD countries. Lastly, this paper concludes that a sustainable economic growth and structural transformation of growth model are the fundamental means to taming China＇s balance sheet risks.展开更多
Kirigami arts have provided a more promising method for building multiscale structures,which can shape two-dimensional(2D)sheets into three-dimensional(3D)configurations by cutting and folding.Here,we first carried ou...Kirigami arts have provided a more promising method for building multiscale structures,which can shape two-dimensional(2D)sheets into three-dimensional(3D)configurations by cutting and folding.Here,we first carried out a theoretical analysis of the mechanical properties of 2D honeycomb lattice structures and experimental verification combined with finite element(FE)simulation.Furthermore,a series of thick-walled 3D kirigami-inspired honeycomb(TW3KH)structures with different mechanical properties were designed and fabricated on the exploration and optimization of geometric parameters of 2D honeycomb structures.The investigations of folding feasibility,self-expansion,and self-folding performance experimentally showed that our designed four-dimensional(4D)printing structure had good programmability and shape memory capability and a large volume change ratio during shape change.Meanwhile,research on its compression deformation behavior found that the TW3KH structures can recover load-bearing capacity very well when the angle is positive.Therefore,these TW3KH structures have great advantages in space-saving smart load-bearing equipment.展开更多
The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the grow...The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the growth of China's industrial economy increased from the annual average of 34.07%to 89.28%while the contribution of TFP dived from the annual average of 47.34%to-4.08%.Meanwhile,TFP growth rates dropped from the annual average of 4.6%to-0.05%and marginal capital output ratio went down from0.61 in 2002 to 0.28 in 2012.This indicates that the investment-driven pattern of China's industrial growth has been confronted with severe inefficiency.Further research suggests that the tendency of worsening industrial growth efficiency already became significant prior to the global financial crisis of 2008 and the eruption of the global financial crisis is not the fundamental reason for the worsening of efficiency and only exacerbated its tendency.The current government-led and investment-driven pattern of industrial growth is the root cause of such efficiency deterioration.Therefore,in order to achieve the transition towards innovation- and efficiency-driven growth pattern,the key is to make an appropriate distinction in the relationship between market and government,i.e.,the government must create a perfect institutional system where the market plays a decisive role and take proactive initiative to promote technology innovation and transfer on the basis of respecting market mechanism and the intent of market entities.展开更多
A novel approach to extract edge features from wideband echo is proposed. The set of extracted features not only represents the echo waveform in a concise way, but also is sufficient and well suited for classification...A novel approach to extract edge features from wideband echo is proposed. The set of extracted features not only represents the echo waveform in a concise way, but also is sufficient and well suited for classification of non-stationary echo data from objects with different property.The feature extraction is derived from the Discrete Dyadic Wavlet Transform (DDWT) of the echo through the undecimated algorithm. The motivation we use the DDWT is that it is time-shift-invariant which is beneficial for localization of edge, and the wavelet coefficients at larger scale represent the main shape feature of echo, i.e. edge, and the noise and modulated high-frequency components are reduced with scale increased. Some experimental results using real data which contain 144 samples from 4 classes of lake bottoms with different sediments are provided. The results show that our approach is a prospective way to represent wideband echo for reliable recognition of nonstationary echo with great variability.展开更多
基金sponsored by the National Natural Science Foundation of China(Nos.52174002&52204008)the Heilongjiang Provincial Natural Science Foundation of China(No.LH2022E020).
文摘During horizontal well drilling,the interaction between drilling fluid and cuttings entering the annulus generates diverse flow patterns.These solid-liquid two-phase flow patterns must be accurately predicted to optimize the determination of hydraulic parameters and improve the efficiency of cuttings transport.Accordingly,this study identified flow patterns and conducted transition experiments under different inclination angles using a visualized wellbore annulus apparatus(120 mm outer diameter/73 mm inner diameter).Through direct visual observations,four primary flow patterns were systematically classified on the basis of the solid-liquid two-phase flow behaviors identified in the experiments:stable bed(SB),sand wave(SW),sand dune(SD),and bed load(BL)flows.The experimental data were then used to construct flow pattern maps with solid/liquid phases as axes,after which the transition boundaries between different flow patterns were established.The morphological characteristics and transition mechanisms of SB,SW,SD,and BL flows were systematically analyzed to develop three predictive models of the fluid dynamics principles governing these flow patterns’transitions:(1)A transition boundary model of SB and SW flows was established using Kelvin-Helmholtz stability,for which a stability analysis of solid-liquid two-phase flow in deviated and horizontal annuli was carried out.(2)A transition boundary model of SW and SD flows was constructed through an analysis of the geometric features of sand waves in the annuli,with the critical ratio of the average height of a cuttings bed to its height after erosion being 0.45.(3)A traditional critical velocity model was refined by adjusting the von Karman constant to account for the effect of solid volume concentration,yielding a boundary model for the transition of SW or SD flow into BL flow.All the models were experimentally validated.Finally,we integrated the models to develop a unified method for identifying and classifying the patterns typifying solid-liquid two-phase flow in deviated and horizontal annuli.
基金financed by the National Youth Sciences Foundation of China (No. 41502044)
文摘The role of authigenic clay growth in clay gouge is increasingly recognized as a key to understanding the mechanics of berittle faulting and fault zone processes,including creep and seismogenesis,and providing new insights into the ongoing debate about the frictional strength of brittle fault(Haines and van der Pluijm,2012).However,neither the conditions nor the processes which
文摘Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered ＂concrete＂, ＂man-centered＂, and ＂ordinal＂; while the western one is believed to be ＂abstract＂, ＂object-centered＂, and ＂conversed＂. These are the decisive factors for the existence of the differences in language expressing. It is of great importance to study these differences and make some adjustments in terms of syntactic structure, semantic focus, and time order so as to achieve a natural rending.
文摘Based on the characteristic of ‘one river one oasis’ in the arid areas, the Yerqiang River Basin, which is the largest irrigated area of Xinjiang, is taken as an example in this paper, and the regional water circulation pattern is investigated through the analysis of 60 groups of isotope data in the basin. From the phreatic evaporation data analysis of different soils, we study the law of phreatic evaporation, complete the research of the main consumption path of the groundwater, and improve the assessment precision of water resources. The transformation mount of regional water resources are predicted by calculation, which provides a scientific basis for water resources assessment and allocation in arid regions, and offers a new method for the study of regional water circulation patterns.
基金supported by the National Natural Science Foundation of China(11242011 and 11021202)
文摘Abstract In periodic cellular structures, novel pattern transformations are triggered by a reversible elastic instability under the axial compression. Based on the deformation-triggered new pattern, periodic cellular structures can achieve special mechanical properties. In this paper, the designed architecture materials which include elastomer matrixes containing empty holes or filled holes with hydrogel material are modeled and simulated to investigate the mechanical property of the periodic materials. By analyzing the relationship between nominal stress and nominal strain of periodic material, and the corresponding deformed patterns, the influence of geometry and shapes of the holes on the mechanical property of architecture material is studied in more details. We hope this study can provide future perspectives for the deformation-triggered periodic structures.
文摘The year of 2000 is at the turn of the century as well as of the millennium. Themankind waves farewell to the 20th century as well as the second millenniumand welcomes the 21st century and the third millennium. At this special juncture,looking closely at the future based on understanding which was obtained from re-viewing and summarizing the past and present world politics from historical andphilosophical standpoints, we can find that it has become an unavoidable subject onhow to regard the trend of the world pattern toward multi-polarization and respon-sibility adjustment arising from it.
文摘In coping with the global financial crisis, all levels of the Chinese government and foreign trade firms have not only created new practices but have also changed their goal from transforming the growth pattern of foreign trade to transforming the development pattern of joreign trade. China＇s experience shows that economic instruments such as Net Barter Terms of Trade （NBTT） and the smile curve theory have limitations when it comes to interpreting foreign trade. If used improperly, scientific theories often lead to.fallacies. Transjbrming the development pattern of China＇s .foreign trade requires the following changes： national income distribution, foreign trade competition, market exploration, and resource utilization. We advise that competent authorities create a reasonable and operational system of assessment indicators.
文摘The development of modern science and technology in China involved three transformations: from a traditional mindset to a modern one through the enlightenment of scientific thought, from the Anglo-Saxon pattern to the Soviet pattern in the process of instituting the Chinese system of science and technology, and from national defence to economics due to an awakening of technical economics after the ‘Cultural Revolution'. This paper surveys the political background of the second transformation. The idea of‘doing science for science's sake' never had a footing in China because the Chinese began to learn about modern science and technology only under the threat of colonists' gunboats. Developing science and technology has always been one of the means for China to cast off national humiliation and regain its status as a major country in the world. Compared with science and technology in other countries, Chinese science and technology were more susceptible to the international political environment and domestic political situation. It took about two decades, between the establishment of the Academia Sinica in 1928 and the inauguration of the Chinese Academy of Sciences in 1949, for China to form its system of science and technology. The system had three successive configurations because of the international competition among Japan, the US and the Soviet Union over China, and the domestic political contest between the Chinese Nationalist Party or Kuomintang(founded by Sun Yat-sen in 1912) and the Communist Party of China. China's science and technology system started by modelling itself on its counterparts in Europe and America. After undergoing a series of unconventional developments during the War of Resistance against Japanese Aggression(1931–1945) and the War of Liberation(1946–1949), the system transformed to the Soviet pattern after the establishment of the People's Republic of China.
文摘Over the past 20 years, China has made spectacular achievements in economic growth as well as in thetransformation of economic growth pattern. Industrial structure is being updated, and technology is playing a more andmore important role in economic development. The energy and resource consumption in many industries and enterprisesare reducing. However, we should realize that there are still many problems in changing the economic growth pattern,such as high input, high consumption, high discharge, inharmony, recycling difficulty, and low efficiency, which havegreatly impaired and restrict Chinese economic development. Therefore, the fundamental change of the economic growthpattern is inevitable. Based on the analysis on the status quo and the exploit of resources, this paper suggests that thetransformation from unsustainable to sustainable growth is the only choice in changing the economic growth pattern. Inaddition, the transformation should not completely rely on the fundamental effects of market mechanism. We should makefull use of the power of governments to speed up the transformation of economic system.
文摘Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D map. The scheme of regional geochemical division includes non supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.
基金Interim results for the state social science foundation key project ＂Raising Macro Regulation Level and Maintain Fast and Steady Economic Growth＂ （approve No. 09＆ZD017） and ＂Funding Program for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality＂ （approve No. 00491162340 142）.
文摘The BRICS （Brazil, Russia, India, China and South Africa） and other emerging economies have become a driving global force for the past twenty years. However, their growth patterns are obsolete, impeding the quality and competitiveness of their economic growth, while simultaneously threatening the sustainability of their economic convergence with developed nations. Transforming the domestic growth pattern-the solution to the middle-income trap-has therefore become a key priority for each of these economies. This paper presents a comparative analysis of how to transform the pattern of economic growth in BRICS and achieve sustainable economic convergence with a comparative analysis of the pattern of economic growth and problems among BRICS countries.
文摘Using available data and necessary estimations, this paper provides a tentative picture of the balance sheet of China＇s sovereign account between 2000 and 2010. The main findings indicate that the net worth of China＇s sovereign assets had been positive and increasing during the period under review. This implies that the Chinese government has sufficient sovereign assets to cover its sovereign liabilities, therefore the likelihood of a sovereign debt crisis in China is extremely low in the near term. Moreover, although China＇s leverage ratio （total liabilities/GDP） is far lower compared to advanced economies, it seems higher than that of other major emerging economies such as Brazil, Russia, and India （BRIC）. In fact, the leverage ratio has been increasing rapidly over recent years and requires special attention. In particular, according to sector-specific analysis, high corporate liability ratios （percentage to GDP） constitute a major concern of China＇s national balance sheet. In 2010, this liability ratio exceeded l OO percent, which exceeds the 90 percent level observed in OECD countries. Lastly, this paper concludes that a sustainable economic growth and structural transformation of growth model are the fundamental means to taming China＇s balance sheet risks.
基金This work was supported by the National Natural Science Foundation of China(Nos.12072094 and 12172106).
文摘Kirigami arts have provided a more promising method for building multiscale structures,which can shape two-dimensional(2D)sheets into three-dimensional(3D)configurations by cutting and folding.Here,we first carried out a theoretical analysis of the mechanical properties of 2D honeycomb lattice structures and experimental verification combined with finite element(FE)simulation.Furthermore,a series of thick-walled 3D kirigami-inspired honeycomb(TW3KH)structures with different mechanical properties were designed and fabricated on the exploration and optimization of geometric parameters of 2D honeycomb structures.The investigations of folding feasibility,self-expansion,and self-folding performance experimentally showed that our designed four-dimensional(4D)printing structure had good programmability and shape memory capability and a large volume change ratio during shape change.Meanwhile,research on its compression deformation behavior found that the TW3KH structures can recover load-bearing capacity very well when the angle is positive.Therefore,these TW3KH structures have great advantages in space-saving smart load-bearing equipment.
文摘The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the growth of China's industrial economy increased from the annual average of 34.07%to 89.28%while the contribution of TFP dived from the annual average of 47.34%to-4.08%.Meanwhile,TFP growth rates dropped from the annual average of 4.6%to-0.05%and marginal capital output ratio went down from0.61 in 2002 to 0.28 in 2012.This indicates that the investment-driven pattern of China's industrial growth has been confronted with severe inefficiency.Further research suggests that the tendency of worsening industrial growth efficiency already became significant prior to the global financial crisis of 2008 and the eruption of the global financial crisis is not the fundamental reason for the worsening of efficiency and only exacerbated its tendency.The current government-led and investment-driven pattern of industrial growth is the root cause of such efficiency deterioration.Therefore,in order to achieve the transition towards innovation- and efficiency-driven growth pattern,the key is to make an appropriate distinction in the relationship between market and government,i.e.,the government must create a perfect institutional system where the market plays a decisive role and take proactive initiative to promote technology innovation and transfer on the basis of respecting market mechanism and the intent of market entities.
文摘A novel approach to extract edge features from wideband echo is proposed. The set of extracted features not only represents the echo waveform in a concise way, but also is sufficient and well suited for classification of non-stationary echo data from objects with different property.The feature extraction is derived from the Discrete Dyadic Wavlet Transform (DDWT) of the echo through the undecimated algorithm. The motivation we use the DDWT is that it is time-shift-invariant which is beneficial for localization of edge, and the wavelet coefficients at larger scale represent the main shape feature of echo, i.e. edge, and the noise and modulated high-frequency components are reduced with scale increased. Some experimental results using real data which contain 144 samples from 4 classes of lake bottoms with different sediments are provided. The results show that our approach is a prospective way to represent wideband echo for reliable recognition of nonstationary echo with great variability.
