Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent fe...Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.展开更多
Ambiguity is a unique linguistic feature and is caused by many factors. This paper first introduces the definitions of ambiguity and then mainly illustrates ambiguity in our daily language usage in both English and Ch...Ambiguity is a unique linguistic feature and is caused by many factors. This paper first introduces the definitions of ambiguity and then mainly illustrates ambiguity in our daily language usage in both English and Chinese from phonetic level and syntactic level. People can learn the relationships among those levels and grasp the rule of learning language. Thus, people can realize the complexity and importance of using language and know that it is not easy to express ideas accurately.展开更多
The finite element method is first introduced into the design process of detecting electrodes of three electrode capacitance fuze, the mutual capacitance of the fuze and target is calculated by the finite element met...The finite element method is first introduced into the design process of detecting electrodes of three electrode capacitance fuze, the mutual capacitance of the fuze and target is calculated by the finite element method, which provides the parameters for simulation circuit and design of detecting electrode. The finite element method pierces the traditional method of designing detecting electrode-design, test and adjustment. The system capacitance can be calculated accurately and the performance can be predicted in the design period of the detecting electrode, which saves a lot of research fee. The capacitances of a mortar shell fuze above ground 2 m and lower are given. After putting the computing data into simulating circuit, the demodulation voltage can be obtained, its changing trend is in agreement with the tested result.展开更多
Two compounds were isolated from ethyl acetate extract of the fermentation of fungus 07-11, which obtained from the soil of Yunnan Province. They were identified as N-(4-hydroxy-2-methoxyphenyl) acetamide (1) and ergo...Two compounds were isolated from ethyl acetate extract of the fermentation of fungus 07-11, which obtained from the soil of Yunnan Province. They were identified as N-(4-hydroxy-2-methoxyphenyl) acetamide (1) and ergosta-7,22-diene-3,6-dione (2) respectively on the basis of spectral analyses and physical and chemical identifications. Compound 1 was a new natural product. Compound 2 was firstly isolated from its genus. Spectral data of 1 and complete 1H NMR data of 2 were reported for the first time.展开更多
Nanoindentation tests performed in a commercial atomic force microscope have been utilized to directly measure the elastic modulus and the hardness of single crystal copper thin films fabricated by the vacuum vapor de...Nanoindentation tests performed in a commercial atomic force microscope have been utilized to directly measure the elastic modulus and the hardness of single crystal copper thin films fabricated by the vacuum vapor deposition technique. Nanoindentation tests were conducted at various indentation depths to study the effect of indentation depths on the mechanical properties of thin films. The results were interpreted by using the Oliver-Pharr method with which direct observation and measurement of the contact area are not required. The elastic modulus of the single crystal copper film at various indentation depths was determined as (67.0±(6.9) GPa) on average which is in reasonable agreement with the results reported in literature. The indentation hardness constantly increases with decreasing indentation depth, indicating a strong size effect.展开更多
In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed thr...In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed through transient and static simulation.In this work,the theoretical deformation model for riveting assembly is established with round head rivet.The simulation analysis for riveting deformation is carried out with the riveting assembly piece including four rivets,which comparing with the measuring points experiment results of riveting test piece through dealing with the experimental data using the point coordinate transform method and the space line fitting method.Simultaneously,the deformation deviation of the overall thin-wall parts assembly structure is analyzed through finite element simulation;and its results are verified by the measuring experiment for riveting assembly with the deformation deviation of some key points on the thin-wall parts.Through the comparison analysis,it is shown that the simulation results agree well with the experimental results,which proves the correctness and effectiveness of the theoretical analysis,simulation results and the given experiment data processing method.Through the study on the riveting assembly for thin-wall parts,it will provide a theoretical foundation for improving thin-wall parts assembly quality of large antenna in future.展开更多
A displacement survey method that can be used in fields such as tunnel engineering, huge dam engineering and so on is introduced. According to this method, a series of measuring stations are set along a fold line, and...A displacement survey method that can be used in fields such as tunnel engineering, huge dam engineering and so on is introduced. According to this method, a series of measuring stations are set along a fold line, and a number of bi-direction laser beams and 2-D displacement sensors are used to realize the line and angle displacement measurements to obtain the distortion information of each point. The calculation formulas are given, and the errors are analyzed. This method can also be used in other distortion-measurement fields such as building, bridge and mountain distortion measurements.展开更多
Both theoretical and field observations were examined to study the close relationship between soil degeneration and the evolution of grassland vegetation. A general n-species model of equal competition under different...Both theoretical and field observations were examined to study the close relationship between soil degeneration and the evolution of grassland vegetation. A general n-species model of equal competition under different degrees of soil degradation was applied to field data in order to probe the dynamic processes and mechanisms of vegetation evolution due to the effects of the soil's ecological deterioration on grassland vegetation. Comparisons were made between the theoretical results and the practical surveys with satisfactory results.展开更多
In the Pearl River Delta (PRD), there is severe competition between container ports, particularly those in Hong Kong, Shenzhen, and Guangzhou, for collecting international maritime container cargo. In addition, the se...In the Pearl River Delta (PRD), there is severe competition between container ports, particularly those in Hong Kong, Shenzhen, and Guangzhou, for collecting international maritime container cargo. In addition, the second phase of the Nansha terminal in Guangzhou’s port and the first phase of the Da Chang Bay container terminal in Shenzhen opened last year. Under these circumstances, there is an increasing need to quantitatively measure the impact these infrastructure investments have on regional cargo flows. The analysis should include the effects of container terminal construction, berth deepening, and access road construction. The authors have been developing a model for international cargo simulation (MICS) which can simulate the movement of cargo. The volume of origin-destination (OD) container cargo in the East Asian region was used as an input, in order to evaluate the effects of international freight transportation policies. This paper focuses on the PRD area and, by incorporating a more detailed network, evaluates the impact of several infrastructure investment projects on freight movement.展开更多
The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat...The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.展开更多
To study battle-field simulation methods based on Vega,a virtual battle-field simulated by an imaginary combat happened on the sea was designed. The simulation framework in the sea battle-filed included helicopter sim...To study battle-field simulation methods based on Vega,a virtual battle-field simulated by an imaginary combat happened on the sea was designed. The simulation framework in the sea battle-filed included helicopter simulation,fire simulation, collision detection and detonation, and simulation of dynamic sea surface. The method to build the simulation environments and actions to them was discussed. And the simulation experiments were conducted.,It is indicated that the simulated sea battle-field based on Vega is feasible and helpful for forces and battle-field.展开更多
Prior group-based fingerprinting achieves better detection performance when colluders are from the same group. But in digital wholesale and needs to be identified retail, the middleman as well as customers especially ...Prior group-based fingerprinting achieves better detection performance when colluders are from the same group. But in digital wholesale and needs to be identified retail, the middleman as well as customers especially against group colluding attack. The group tracing is neglected in previous works. In this paper, we propose a novel multimedia group fingerprint to trace malicious middlemen along with customers. We explore the quality of the non degenerate linear shift register sequence (NDLSRS) which is convenient in group initialization and management. The theoretic analysis and simulation experiment results show that NDLSRS has good resistance against attacks from colluding groups/ members even after its volume expanded.展开更多
This paper falls into two parts. In the first part, the widely used analytical-empirical method of pavement design and evaluation is discussed and in the second part two simulation models are presented to predict the ...This paper falls into two parts. In the first part, the widely used analytical-empirical method of pavement design and evaluation is discussed and in the second part two simulation models are presented to predict the design of flexible pavement. Analytical results are compared with simulation models.展开更多
The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the prop...The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the proposed model, robot that mimics the behavior of bacteria is able to determine an optimal collision-free path between a start and a target point in the environment surrounded by obstacles. In the simulation, two test scenarios of static environment with different number obstacles were adopted to evaluate the performance of the proposed method. Simulation results show that the robot which reflects the bacterial foraging behavior can adapt to complex environments in the planned trajectories with both satisfactory accuracy and stability.展开更多
The advantage of lidar over other wind sensors is presented in this paper. With more than 20 years research, the development of the space-borne wind lidar is reviewed. Longer-term investigation has made many technolog...The advantage of lidar over other wind sensors is presented in this paper. With more than 20 years research, the development of the space-borne wind lidar is reviewed. Longer-term investigation has made many technologies suitable for the wind lidar measurement from an orbital platform become mature. However, there are still some problems to be solved. In order to obtain the optimal performance in wind detection, great importance is being attached to the simulation of a virtual space-borne wind lidar system on computer as developed by NASA and ESA.展开更多
To study the problem of obstacle detection based on multi-sensors data fusion,the multi-target tracking theory and techniques are introduced into obstacle detection systems,and the exact position of obstacle can be de...To study the problem of obstacle detection based on multi-sensors data fusion,the multi-target tracking theory and techniques are introduced into obstacle detection systems,and the exact position of obstacle can be determined.Data fusion problems are discussed directly based on achievable data from some sensors without considering the specific structure of each individual sensor.With respect to normal linear systems and nonlinear systems,the corresponding algorithms are proposed.The validity of the method is confirmed by simulation results.展开更多
The simulation of the transport and fate of an oil slick, accidentally introduced in the marine environment, is the focus of this research. An oil spill dispersion forecasting system (DIAVLOS forecasting system), ba...The simulation of the transport and fate of an oil slick, accidentally introduced in the marine environment, is the focus of this research. An oil spill dispersion forecasting system (DIAVLOS forecasting system), based on wind, wave and ocean circulation forecasting models is developed. The 3-D oil spill model, by the University of Thessaloniki, is based on a Lagrangian (tracer) model that accounts for the transport-diffusion-dispersion and physicochemical evolution of an oil slick. The high resolution meteorological, hydrodynamic and wave models are coupled with the operational systems ALERMO and SKIRON of the University of Athens. The modelling system was successfully assembled and tested under theoretical and realistic scenarios, in order to be applied in forecasting mode and be used by local authorities when an accident occurs. As a result, a 48-hours oil spill dispersion forecasting system was synthesized aiming primarily at the oil spill management at the Burgas-Alexandroupolis oil-pipe terminal, part of a greater busy coastal basin in North Aegean.展开更多
The conservative Additive Increase Multiplicative Decrease mechanism of traditional TCP causes the link under-utilization in the Wide Area Networks(WANs) due to the WANs' intrinsic nature of high latency and high ...The conservative Additive Increase Multiplicative Decrease mechanism of traditional TCP causes the link under-utilization in the Wide Area Networks(WANs) due to the WANs' intrinsic nature of high latency and high packet loss.To alleviate the problem,we present the design and implantation of STAG,an Acceleration Gateway with Split-TCP in the paper.STAG is built on embedded network equipment and acts as a transparent proxy.In STAG,a new improved congestion control method named Rapid TCP is adopted,which determines whether or not to decrease the congestion window based on the packet loss trend.In particular,in the fast recovery phase,it chooses different window adjustment strategies based on the current size of congestion window to achieve higher utilization.The performance validation of STAG is done on both our emulation testbed and the real wide area network.The results show that STAG with Rapid TCP effectively adapts to the high loss network environment and significantly speeds up the applications without loss of fairness.展开更多
文摘Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.
文摘Ambiguity is a unique linguistic feature and is caused by many factors. This paper first introduces the definitions of ambiguity and then mainly illustrates ambiguity in our daily language usage in both English and Chinese from phonetic level and syntactic level. People can learn the relationships among those levels and grasp the rule of learning language. Thus, people can realize the complexity and importance of using language and know that it is not easy to express ideas accurately.
文摘The finite element method is first introduced into the design process of detecting electrodes of three electrode capacitance fuze, the mutual capacitance of the fuze and target is calculated by the finite element method, which provides the parameters for simulation circuit and design of detecting electrode. The finite element method pierces the traditional method of designing detecting electrode-design, test and adjustment. The system capacitance can be calculated accurately and the performance can be predicted in the design period of the detecting electrode, which saves a lot of research fee. The capacitances of a mortar shell fuze above ground 2 m and lower are given. After putting the computing data into simulating circuit, the demodulation voltage can be obtained, its changing trend is in agreement with the tested result.
基金The present work was supported by Foundation of State Key Basic Research and Development Project (G1998051100)
文摘Two compounds were isolated from ethyl acetate extract of the fermentation of fungus 07-11, which obtained from the soil of Yunnan Province. They were identified as N-(4-hydroxy-2-methoxyphenyl) acetamide (1) and ergosta-7,22-diene-3,6-dione (2) respectively on the basis of spectral analyses and physical and chemical identifications. Compound 1 was a new natural product. Compound 2 was firstly isolated from its genus. Spectral data of 1 and complete 1H NMR data of 2 were reported for the first time.
文摘Nanoindentation tests performed in a commercial atomic force microscope have been utilized to directly measure the elastic modulus and the hardness of single crystal copper thin films fabricated by the vacuum vapor deposition technique. Nanoindentation tests were conducted at various indentation depths to study the effect of indentation depths on the mechanical properties of thin films. The results were interpreted by using the Oliver-Pharr method with which direct observation and measurement of the contact area are not required. The elastic modulus of the single crystal copper film at various indentation depths was determined as (67.0±(6.9) GPa) on average which is in reasonable agreement with the results reported in literature. The indentation hardness constantly increases with decreasing indentation depth, indicating a strong size effect.
基金Project(51675100)supported by the National Natural Science Foundation of ChinaProject(2016ZX04004008)supported by the National Numerical Control Equipment Major Project of ChinaProject(6902002116)supported by the Foundation of Certain Ministry of China
文摘In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed through transient and static simulation.In this work,the theoretical deformation model for riveting assembly is established with round head rivet.The simulation analysis for riveting deformation is carried out with the riveting assembly piece including four rivets,which comparing with the measuring points experiment results of riveting test piece through dealing with the experimental data using the point coordinate transform method and the space line fitting method.Simultaneously,the deformation deviation of the overall thin-wall parts assembly structure is analyzed through finite element simulation;and its results are verified by the measuring experiment for riveting assembly with the deformation deviation of some key points on the thin-wall parts.Through the comparison analysis,it is shown that the simulation results agree well with the experimental results,which proves the correctness and effectiveness of the theoretical analysis,simulation results and the given experiment data processing method.Through the study on the riveting assembly for thin-wall parts,it will provide a theoretical foundation for improving thin-wall parts assembly quality of large antenna in future.
基金The Second Artillery Engineering Project(EP403040101)
文摘A displacement survey method that can be used in fields such as tunnel engineering, huge dam engineering and so on is introduced. According to this method, a series of measuring stations are set along a fold line, and a number of bi-direction laser beams and 2-D displacement sensors are used to realize the line and angle displacement measurements to obtain the distortion information of each point. The calculation formulas are given, and the errors are analyzed. This method can also be used in other distortion-measurement fields such as building, bridge and mountain distortion measurements.
文摘Both theoretical and field observations were examined to study the close relationship between soil degeneration and the evolution of grassland vegetation. A general n-species model of equal competition under different degrees of soil degradation was applied to field data in order to probe the dynamic processes and mechanisms of vegetation evolution due to the effects of the soil's ecological deterioration on grassland vegetation. Comparisons were made between the theoretical results and the practical surveys with satisfactory results.
文摘In the Pearl River Delta (PRD), there is severe competition between container ports, particularly those in Hong Kong, Shenzhen, and Guangzhou, for collecting international maritime container cargo. In addition, the second phase of the Nansha terminal in Guangzhou’s port and the first phase of the Da Chang Bay container terminal in Shenzhen opened last year. Under these circumstances, there is an increasing need to quantitatively measure the impact these infrastructure investments have on regional cargo flows. The analysis should include the effects of container terminal construction, berth deepening, and access road construction. The authors have been developing a model for international cargo simulation (MICS) which can simulate the movement of cargo. The volume of origin-destination (OD) container cargo in the East Asian region was used as an input, in order to evaluate the effects of international freight transportation policies. This paper focuses on the PRD area and, by incorporating a more detailed network, evaluates the impact of several infrastructure investment projects on freight movement.
基金Project(2011-0021376) supported by Basic Science Program through the National Research Foundation (NRF) Funded by the Ministry of Education,Science and Technology of Korea
文摘The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.
基金Sponsored by the Heilongjiang Natural Fund for Oversea People(Grant No.LC06C08)Heilongjiang Education Science Research Fund for Oversea People (Grant No. 1151hq008)+3 种基金Heilongjiang Postdoctor Research Fund (Grant No.LBH-Z06106)the Natural Science Foundation of China (Grant No.60671011)the Science Fund for Distinguished Young Scholars of Heilongjiang Province (Grant No. JC200611)the Foundation of Harbin Instituteof Technology (Grant No.HIT.2003.53)
文摘To study battle-field simulation methods based on Vega,a virtual battle-field simulated by an imaginary combat happened on the sea was designed. The simulation framework in the sea battle-filed included helicopter simulation,fire simulation, collision detection and detonation, and simulation of dynamic sea surface. The method to build the simulation environments and actions to them was discussed. And the simulation experiments were conducted.,It is indicated that the simulated sea battle-field based on Vega is feasible and helpful for forces and battle-field.
文摘Prior group-based fingerprinting achieves better detection performance when colluders are from the same group. But in digital wholesale and needs to be identified retail, the middleman as well as customers especially against group colluding attack. The group tracing is neglected in previous works. In this paper, we propose a novel multimedia group fingerprint to trace malicious middlemen along with customers. We explore the quality of the non degenerate linear shift register sequence (NDLSRS) which is convenient in group initialization and management. The theoretic analysis and simulation experiment results show that NDLSRS has good resistance against attacks from colluding groups/ members even after its volume expanded.
文摘This paper falls into two parts. In the first part, the widely used analytical-empirical method of pavement design and evaluation is discussed and in the second part two simulation models are presented to predict the design of flexible pavement. Analytical results are compared with simulation models.
基金Project(61173032)supported by the National Natural Science Foundation of ChinaProject(20090406)supported by the Tianjin Scientific and Technological Development Fund of Higher Education of China
文摘The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the proposed model, robot that mimics the behavior of bacteria is able to determine an optimal collision-free path between a start and a target point in the environment surrounded by obstacles. In the simulation, two test scenarios of static environment with different number obstacles were adopted to evaluate the performance of the proposed method. Simulation results show that the robot which reflects the bacterial foraging behavior can adapt to complex environments in the planned trajectories with both satisfactory accuracy and stability.
基金supported by National High Tech 863 Project(No.2002AA135280)National Natural Science Foundation of China No.40176011International Bureau of BMBF
文摘The advantage of lidar over other wind sensors is presented in this paper. With more than 20 years research, the development of the space-borne wind lidar is reviewed. Longer-term investigation has made many technologies suitable for the wind lidar measurement from an orbital platform become mature. However, there are still some problems to be solved. In order to obtain the optimal performance in wind detection, great importance is being attached to the simulation of a virtual space-borne wind lidar system on computer as developed by NASA and ESA.
基金Sponsored by the Science Foundation for Youths of Heilongjiang Province(Grant No.QC08C05)
文摘To study the problem of obstacle detection based on multi-sensors data fusion,the multi-target tracking theory and techniques are introduced into obstacle detection systems,and the exact position of obstacle can be determined.Data fusion problems are discussed directly based on achievable data from some sensors without considering the specific structure of each individual sensor.With respect to normal linear systems and nonlinear systems,the corresponding algorithms are proposed.The validity of the method is confirmed by simulation results.
文摘The simulation of the transport and fate of an oil slick, accidentally introduced in the marine environment, is the focus of this research. An oil spill dispersion forecasting system (DIAVLOS forecasting system), based on wind, wave and ocean circulation forecasting models is developed. The 3-D oil spill model, by the University of Thessaloniki, is based on a Lagrangian (tracer) model that accounts for the transport-diffusion-dispersion and physicochemical evolution of an oil slick. The high resolution meteorological, hydrodynamic and wave models are coupled with the operational systems ALERMO and SKIRON of the University of Athens. The modelling system was successfully assembled and tested under theoretical and realistic scenarios, in order to be applied in forecasting mode and be used by local authorities when an accident occurs. As a result, a 48-hours oil spill dispersion forecasting system was synthesized aiming primarily at the oil spill management at the Burgas-Alexandroupolis oil-pipe terminal, part of a greater busy coastal basin in North Aegean.
基金supported by the National Natural Science Foundation of China(Grant nos.61173169,61103204,and 61402542)the open funding of Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory(Grant no.ITDU14010/KX142600017)the Postgraduate Innovative Research Project of Hunan Province(No.CX2012B065)
文摘The conservative Additive Increase Multiplicative Decrease mechanism of traditional TCP causes the link under-utilization in the Wide Area Networks(WANs) due to the WANs' intrinsic nature of high latency and high packet loss.To alleviate the problem,we present the design and implantation of STAG,an Acceleration Gateway with Split-TCP in the paper.STAG is built on embedded network equipment and acts as a transparent proxy.In STAG,a new improved congestion control method named Rapid TCP is adopted,which determines whether or not to decrease the congestion window based on the packet loss trend.In particular,in the fast recovery phase,it chooses different window adjustment strategies based on the current size of congestion window to achieve higher utilization.The performance validation of STAG is done on both our emulation testbed and the real wide area network.The results show that STAG with Rapid TCP effectively adapts to the high loss network environment and significantly speeds up the applications without loss of fairness.