Search engines have greatly helped us to find the desired information from the Internet. Most search engines use keywords matching technique. This paper discusses a Dynamic Knowledge Base based Search Engine (DKBSE)...Search engines have greatly helped us to find the desired information from the Internet. Most search engines use keywords matching technique. This paper discusses a Dynamic Knowledge Base based Search Engine (DKBSE), which can expand the user's query using the keywords' concept or meaning. To do this, the DKBSE needs to construct and maintain the knowledge base dynamically via the system's searching results and the user's feedback information. The DKBSE expands the user's initial query using the knowledge base, and returns the searched information after the expanded query.展开更多
The emergence of the somatosensory interactive technology has changed the ways of the interaction between the users and the computers, so that people can control the computers more freely. This paper focuses on the in...The emergence of the somatosensory interactive technology has changed the ways of the interaction between the users and the computers, so that people can control the computers more freely. This paper focuses on the interactive design of the somatosensory games, and combines the Kinect interactive devices with the popular Unity 3D game engines, and analyzes and designs the realization principles of the somatosensory games, the somatosensory games and the digital somatosensory interactive display. Through the design and production of the original game "Dream", the author discusses the design methods of the game interactive experience while abandoning the traditional human-comouter interactive mode.展开更多
The Lagrangian DDM (discrete droplet model) is state-of-the-art for CFD (computational fluid dynamics) simulations of mixture formation and combustion in industrial engines. A commonly known drawback of the DDM ap...The Lagrangian DDM (discrete droplet model) is state-of-the-art for CFD (computational fluid dynamics) simulations of mixture formation and combustion in industrial engines. A commonly known drawback of the DDM approach is the attenuated validity in the dense spray, where the bulk liquid disintegrates into droplets. There the assumption of single droplets surrounded by a homogenous gas field is not reasonable. In this region, the Eulerian-Eulerian multi-phase approach performs better because instead of parcels the spray is represented by the volume fractions of one bulk liquid and several droplet size class phases. A further drawback of the DDM approach is that increasing the spatial resolution of the computational grid leads to a reduced statistical convergence, since the number of spray parcels per computational cell becomes smaller. It is desirable to combine the benefits of both spray approaches in coupled CFD simulations. Therefore, the dense spray region is simulated separately with the Eulerian spray approach on a highly resolved mesh covering only the region close to the nozzle orifice. The entire engine domain with combustion and emission models is simulated with the Eulerian-Lagrangian spray approach for the dilute spray region. The two simulations are coupled through exchange of boundary conditions and model source terms. An on-line coupling interface manages the data transfer between the two simulation clients, i.e., Eulerian spray and engine client. The aim of this work is to extend the coupled spray approach in terms of exchanging combustion related heat and species sources, and consequently creating the link between Eulerian spray and combustion models. The results show mixture formation and combustion in real-case engine simulations, and demonstrate the feasibility of spray model combination in engineering applications.展开更多
Internet based technologies, such as mobile payments, social networks, search engines and cloud computation, will lead to a paradigm shift in financial sector. Beside indirect financing via commercial banks and direct...Internet based technologies, such as mobile payments, social networks, search engines and cloud computation, will lead to a paradigm shift in financial sector. Beside indirect financing via commercial banks and direct financing through security markets, a third way to conduct financial activities will emerge, which we call "internet finance'" This paper presents a detailed analysis of payment, information processing and resource allocation under internet finance.展开更多
The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this paper.Discussions include the combustion characteristics of direct injection engine fueled wi...The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this paper.Discussions include the combustion characteristics of direct injection engine fueled with hydrogen enriched natural gas,visualization study of direct injection combustion of hydrogen enriched natural gas using a constant volume vessel,and the fundamental study of turbulent premixed combustion of hydrogen enriched natural gas.The effect of additional hydrogen on the combustion process of natural gas engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.展开更多
Diesel particulate matter(DPF) is usually employed to meet the stringent regulations on particulate matter(PM) emissions for diesel engine. To resolve the DPF regeneration problem, comprehensive information about the ...Diesel particulate matter(DPF) is usually employed to meet the stringent regulations on particulate matter(PM) emissions for diesel engine. To resolve the DPF regeneration problem, comprehensive information about the factors influencing PM oxidation behaviors must be understood. Large amounts of factors related to PM oxidation activity have been investigated, however, some relations are still ambiguous. This paper reviews the factors related to PM oxidation activity that the factors are divided into the engine-correlated and engine-uncorrelated factors. The methods with both advantages and disadvantages to test the oxidation behaviors are introduced. The microstructure and ingredient being fundamental factors affecting PM oxidation behaviors are as the principle line to correlate PM oxidation behaviors and engine-correlated factors. The relations of engine-correlated factors with oxidation behaviors are obtained though advanced technologies that are mutual complementation. The engine-uncorrelated factors are also reviewed that these factors are vital to oxidation activity changes. Multiple-factor analysis rather than single-factor analysis should be developed to make the oxidation behaviors of diesel PM more clear.展开更多
Quantitative evaluation and driving mechanism analysis of vegetation dynamics are essential for promoting regional sustainable development.In the past 20 years,the ecological environment in Altay Prefecture has change...Quantitative evaluation and driving mechanism analysis of vegetation dynamics are essential for promoting regional sustainable development.In the past 20 years,the ecological environment in Altay Prefecture has changed significantly due to global warming.Meanwhile,with increasing human activities,the spatiotemporal pattern and driving forces of vegetation variation in the area are uncertain and difficult to accurately assess.Hence,we quantified the vegetation growth by using the Normalized Difference Vegetation Index(NDVI)on the Google Earth Engine(GEE).Then,the spatiotemporal patterns of vegetation from 2000 to 2019 were analyzed at the pixel scale.Finally,significance threshold segmentation was performed using meteorological data based on the correlation analysis results,and the contributions of climate change and human activities to vegetation variation were quantified.The results demonstrated that the vegetation coverage in Altay Prefecture is mainly concentrated in the north.The vegetation areas representing significant restoration and degradation from 2000 to 2019 accounted for 24.08% and 1.24% of Altay Prefecture,respectively.Moreover,spatial correlation analysis showed that the areas with significant correlations between NDVI and temperature,precipitation and sunlight hours accounted for 3.3%,6.9% and 20.3% of Altay Prefecture,respectively.In the significant restoration area,18.94% was dominated by multiple factors,while 3.4% was dominated by human activities,and 1.74% was dominated by climate change.Within the significant degradation area,abnormal degradation and climate change controlled 1.07% and 0.17%,respectively.This study revealed the dynamic changes of vegetation and their driving mechanisms in Altay Prefecture,and can provide scientific support for further research on life community mechanism theory and key remediation technology of mountain-water-forest-farmland-lake-grass in Altay Prefecture.展开更多
By using our computational fluid dynamic models, a new type of single engine capable of operating over a wide range of Mach numbers from subsonic to hypersonic regimes is proposed for airplanes, whereas traditional pi...By using our computational fluid dynamic models, a new type of single engine capable of operating over a wide range of Mach numbers from subsonic to hypersonic regimes is proposed for airplanes, whereas traditional piston engines, turbojet engines, and scram engines work only under a narrower range of operating conditions. The new engine has no compressors or turbines such as those used in conventional turbojet engines. An important point is its system of super multijets that collide to compress gas for the transonic regime. Computational fluid dynamics is applied to clarify the potential of this engine. The peak pressure at the combustion center is over 2.5 MPa, while that just before ignition is over 1.0 MPa. The maximum power of this engine will be sufficient for actual use. Under the conditions of higher Mach numbers, the main intake passage located in front of the super multijet nozzles, takes in air more. That results in a ram or scramjet engine for supersonic and hypersonic conditions.展开更多
文摘Search engines have greatly helped us to find the desired information from the Internet. Most search engines use keywords matching technique. This paper discusses a Dynamic Knowledge Base based Search Engine (DKBSE), which can expand the user's query using the keywords' concept or meaning. To do this, the DKBSE needs to construct and maintain the knowledge base dynamically via the system's searching results and the user's feedback information. The DKBSE expands the user's initial query using the knowledge base, and returns the searched information after the expanded query.
文摘The emergence of the somatosensory interactive technology has changed the ways of the interaction between the users and the computers, so that people can control the computers more freely. This paper focuses on the interactive design of the somatosensory games, and combines the Kinect interactive devices with the popular Unity 3D game engines, and analyzes and designs the realization principles of the somatosensory games, the somatosensory games and the digital somatosensory interactive display. Through the design and production of the original game "Dream", the author discusses the design methods of the game interactive experience while abandoning the traditional human-comouter interactive mode.
文摘The Lagrangian DDM (discrete droplet model) is state-of-the-art for CFD (computational fluid dynamics) simulations of mixture formation and combustion in industrial engines. A commonly known drawback of the DDM approach is the attenuated validity in the dense spray, where the bulk liquid disintegrates into droplets. There the assumption of single droplets surrounded by a homogenous gas field is not reasonable. In this region, the Eulerian-Eulerian multi-phase approach performs better because instead of parcels the spray is represented by the volume fractions of one bulk liquid and several droplet size class phases. A further drawback of the DDM approach is that increasing the spatial resolution of the computational grid leads to a reduced statistical convergence, since the number of spray parcels per computational cell becomes smaller. It is desirable to combine the benefits of both spray approaches in coupled CFD simulations. Therefore, the dense spray region is simulated separately with the Eulerian spray approach on a highly resolved mesh covering only the region close to the nozzle orifice. The entire engine domain with combustion and emission models is simulated with the Eulerian-Lagrangian spray approach for the dilute spray region. The two simulations are coupled through exchange of boundary conditions and model source terms. An on-line coupling interface manages the data transfer between the two simulation clients, i.e., Eulerian spray and engine client. The aim of this work is to extend the coupled spray approach in terms of exchanging combustion related heat and species sources, and consequently creating the link between Eulerian spray and combustion models. The results show mixture formation and combustion in real-case engine simulations, and demonstrate the feasibility of spray model combination in engineering applications.
文摘Internet based technologies, such as mobile payments, social networks, search engines and cloud computation, will lead to a paradigm shift in financial sector. Beside indirect financing via commercial banks and direct financing through security markets, a third way to conduct financial activities will emerge, which we call "internet finance'" This paper presents a detailed analysis of payment, information processing and resource allocation under internet finance.
基金supported by the National Natural Science Foundation of China(Grant Nos.51376004 and 51006080)the National Basic Research Program of China("973"Program)(Grant No.2013CB228406)
文摘The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this paper.Discussions include the combustion characteristics of direct injection engine fueled with hydrogen enriched natural gas,visualization study of direct injection combustion of hydrogen enriched natural gas using a constant volume vessel,and the fundamental study of turbulent premixed combustion of hydrogen enriched natural gas.The effect of additional hydrogen on the combustion process of natural gas engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.
基金support by the Science and Technology Planning Project of Hebei Province,China(Grant No.15273703D)
文摘Diesel particulate matter(DPF) is usually employed to meet the stringent regulations on particulate matter(PM) emissions for diesel engine. To resolve the DPF regeneration problem, comprehensive information about the factors influencing PM oxidation behaviors must be understood. Large amounts of factors related to PM oxidation activity have been investigated, however, some relations are still ambiguous. This paper reviews the factors related to PM oxidation activity that the factors are divided into the engine-correlated and engine-uncorrelated factors. The methods with both advantages and disadvantages to test the oxidation behaviors are introduced. The microstructure and ingredient being fundamental factors affecting PM oxidation behaviors are as the principle line to correlate PM oxidation behaviors and engine-correlated factors. The relations of engine-correlated factors with oxidation behaviors are obtained though advanced technologies that are mutual complementation. The engine-uncorrelated factors are also reviewed that these factors are vital to oxidation activity changes. Multiple-factor analysis rather than single-factor analysis should be developed to make the oxidation behaviors of diesel PM more clear.
基金The Science and Technology Project of Xizang Autonomous Region(XZ201901-GA-07)The Key Research and Development Project of Sichuan Science and Technology Department(2021YFQ0042)The Science and Technology Bureau of Altay Region in Yili Kazak Autonomous Prefecture(Y99M4600AL)。
文摘Quantitative evaluation and driving mechanism analysis of vegetation dynamics are essential for promoting regional sustainable development.In the past 20 years,the ecological environment in Altay Prefecture has changed significantly due to global warming.Meanwhile,with increasing human activities,the spatiotemporal pattern and driving forces of vegetation variation in the area are uncertain and difficult to accurately assess.Hence,we quantified the vegetation growth by using the Normalized Difference Vegetation Index(NDVI)on the Google Earth Engine(GEE).Then,the spatiotemporal patterns of vegetation from 2000 to 2019 were analyzed at the pixel scale.Finally,significance threshold segmentation was performed using meteorological data based on the correlation analysis results,and the contributions of climate change and human activities to vegetation variation were quantified.The results demonstrated that the vegetation coverage in Altay Prefecture is mainly concentrated in the north.The vegetation areas representing significant restoration and degradation from 2000 to 2019 accounted for 24.08% and 1.24% of Altay Prefecture,respectively.Moreover,spatial correlation analysis showed that the areas with significant correlations between NDVI and temperature,precipitation and sunlight hours accounted for 3.3%,6.9% and 20.3% of Altay Prefecture,respectively.In the significant restoration area,18.94% was dominated by multiple factors,while 3.4% was dominated by human activities,and 1.74% was dominated by climate change.Within the significant degradation area,abnormal degradation and climate change controlled 1.07% and 0.17%,respectively.This study revealed the dynamic changes of vegetation and their driving mechanisms in Altay Prefecture,and can provide scientific support for further research on life community mechanism theory and key remediation technology of mountain-water-forest-farmland-lake-grass in Altay Prefecture.
文摘By using our computational fluid dynamic models, a new type of single engine capable of operating over a wide range of Mach numbers from subsonic to hypersonic regimes is proposed for airplanes, whereas traditional piston engines, turbojet engines, and scram engines work only under a narrower range of operating conditions. The new engine has no compressors or turbines such as those used in conventional turbojet engines. An important point is its system of super multijets that collide to compress gas for the transonic regime. Computational fluid dynamics is applied to clarify the potential of this engine. The peak pressure at the combustion center is over 2.5 MPa, while that just before ignition is over 1.0 MPa. The maximum power of this engine will be sufficient for actual use. Under the conditions of higher Mach numbers, the main intake passage located in front of the super multijet nozzles, takes in air more. That results in a ram or scramjet engine for supersonic and hypersonic conditions.