Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are presented.The experiment was performed using a scaled model in a tank.In the middle of the ...Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are presented.The experiment was performed using a scaled model in a tank.In the middle of the scaled model,sacrificial specimens with circular pillar and trough shapes which respectively show different bending moment-displacement characteristics were mounted to compare the dynamic collapse characteristics of the hull girder in waves.The specimens were designed by using finite element(FE)-analysis.Prior to the tank tests,static four-point-bending tests were conducted to detect the load-carrying capacity of the hull girder.It was shown that the load-carrying capacity of a ship including reduction of the capacity after the ultimate strength can be reproduced experimentally by employing the trough type specimens.Tank tests using these specimens were performed under a focused wave in which the hull girder collapses under once and repetitive focused waves.It was shown from the multiple collapse tests that the increase rate of collapse becomes higher once the load-carrying capacity enters the reduction path while the increase rate is lower before reaching the ultimate strength.展开更多
This research applies experimental measurements and NUBEAM,ONETWO and TRANSP modules to investigate the shine-through(ST)loss ratio and beam heating percentage of neutral beam injection on EAST.Measurements and simula...This research applies experimental measurements and NUBEAM,ONETWO and TRANSP modules to investigate the shine-through(ST)loss ratio and beam heating percentage of neutral beam injection on EAST.Measurements and simulations confirm that the ST loss ratio increases linearly with beam energy,and decreases exponentially with plasma density.Moreover,using the multi-step fitting method,we present analytical quantitative expressions of ST loss ratio and beam heating percentage,which are valuable for the high parameter long-pulse experiments of EAST.展开更多
L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environme...L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environmental protection were con- cemed greatly. Based on engineering geological environment of L3414 working face and mining factors, the color bore-bole TV inspecting, leakage of drilling fluid monitoring, simulation experiment, numerical computing, in-situ ground stress measurement and subsidence measurement, etal, these programs contribute to the formation of a scientific basis for control water safe mining and normal mining or environmental protection in the condition of existing fully-mechanized mining.展开更多
The damages of different drilling modes to reservoirs are different in types and degrees.In this paper,the geologic characteristics and types of such damages were analyzed.Then,based on the relationship between reserv...The damages of different drilling modes to reservoirs are different in types and degrees.In this paper,the geologic characteristics and types of such damages were analyzed.Then,based on the relationship between reservoir pressure and bottom hole flowing pressure corresponding to different drilling modes,the experimental procedures on reservoir damages in three drilling modes(e.g.gas drilling,liquid-based underbalanced drilling and overbalanced drilling)were designed.Finally,damage simulation experiments were conducted on the tight sandstone reservoir cores of the Jurassic Ahe Fm in the Tarim Basin and Triassic Xujiahe Fm in the central Sichuan Basin.It is shown that the underbalanced drilling is beneficial to reservoir protection because of its less damage on reservoir permeability,but it is,to some extent,sensitive to the stress and the empirical formula of stress sensitivity coefficient is obtained;and that the overbalanced drilling has more reservoir damages due to the invasion of solid and liquid phases.After the water saturation of cores rises to the irreducible water saturation,the decline of gas logging permeability speeds up and the damage degree of water lock increases.It is concluded that the laboratory experiment results of reservoir damage are accordant with the reservoir damage characteristics in actual drilling conditions.Therefore,this method reflects accurately the reservoir damage characteristics and can be used as a new experimental evaluation method on reservoir damage in different drilling modes.展开更多
In order to investigate the data reliability of the core liquid permeability flow experiment evaluation test results, the uncertainty of the test results was evaluated. First of all, the core liquid permeability evalu...In order to investigate the data reliability of the core liquid permeability flow experiment evaluation test results, the uncertainty of the test results was evaluated. First of all, the core liquid permeability evaluation device is used to conduct a complete test according to the industry standard requirements. Then, according to the method in JJF 1059.1-2012 "Evaluation and Expression of Measurement Uncertainty", the known mathematical model is used to accurately identify and calculate each component causing uncertainty in the flow test process. The results show that the uncertainty component caused by mass weighing contributes the most to the combined standard uncertainty, followed by the uncertainty component caused by pressure measurement and the uncertainty component caused by the time flowing through the upper and lower scribing lines of the viscometer, and the accuracy grade of the measuring instrument also has a great influence on the evaluation result of the uncertainty.展开更多
The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built ...The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-tilling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.展开更多
This review article provides a thorough assessment of modern and innovative algorithms for text classification through both observational and experimental evaluations.We propose a new classification system,grounded in...This review article provides a thorough assessment of modern and innovative algorithms for text classification through both observational and experimental evaluations.We propose a new classification system,grounded in methodology,to categorize text classification algorithms into an organized structure from general categories down to particular fine-grained techniques.Drawing on more than 100 academic papers from prominent publishers,our extensive review spans a wide range of algorithms,encompassing traditional,deep learning,and emerging approaches.Through observational studies and comparative experiments among various algorithms,techniques,and methodological categories,we offer detailed insights into the area of text classification.The goal of this survey is to assist scholars in choosing the right methods for specific projects while encouraging further advancements in this area.This detailed examination not only contributes to the scholarly conversation on text classification but also seeks to direct future progress by identifying promising avenues for innovation and enhancement.The primary contributions of this article include the sophisticated methodological classification,a thorough review and examination of state-of-the-art algorithms,along with observational and experimental assessments,and a visionary outlook on the future development of text classification methods.展开更多
Cruise value chain is to take the exchange of cruise products and services as the core in a certain spatial scope,and enterprises with core advantages within or between different industries establish associations in a...Cruise value chain is to take the exchange of cruise products and services as the core in a certain spatial scope,and enterprises with core advantages within or between different industries establish associations in accordance with certain technical and economic conditions,so as to realise the multi-dimensional extension and value appreciation of the cruise value chain in the vertical and horizontal links,and ultimately establish a chain-network type of enterprise strategic alliance.This paper tries to analyse the value-added factors of the cruise industry chain by constructing a multi-level hierarchical structural model with reference to the influencing factor analysis methods of relevant literature-DEMATEL(Decision Making Experiment and Evaluation Experiment)and ISM(Interpretative Structural Model).The study shows that the innovation and scale value-added module in the upstream of the cruise industry chain is the core module of value-added of the whole cruise industry chain,and the value-added mainly originates from the design and manufacturing of cruise ships.The middle reaches of the cruise industry chain are mainly cruise operation enterprises,and the specificity of cruise operation determines that its brand value-added is mainly accomplished through the global layout of multinational corporations,and the cruise brand is able to drive the consumption demand and has value-added ability.The downstream value-added of the cruise industry chain is mainly realised through the increase in profits of cruise tourism service products.展开更多
This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to ...This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents.展开更多
Recent developments have demonstrated that the brake pedal simulator(BPS)is becoming an indispensable apparatus for the break-by-wire systems in future electric vehicles.Its main function is to provide the driver with...Recent developments have demonstrated that the brake pedal simulator(BPS)is becoming an indispensable apparatus for the break-by-wire systems in future electric vehicles.Its main function is to provide the driver with a comfortable pedal feel to improve braking safety and comfort.This paper presents the development and control of an adjustable BPS,using a disk-type magnetorheological(MR)damper as the passive braking reaction generator to simulate the traditional pedal feel.A detailed description of the mechanical design of the MR damper-based BSP(MRDBBPS)is presented in this paper.Several basic performance experiments on the MRDBBPS prototype are conducted.A returnto-zero(RTZ)algorithm is proposed to avoid hysteresis and improve the repeatability of the pedal force.In addition,an RTZ algorithm-based real-time current-tracking controller(RTZRC)is designed in consideration of the response lag of the coil circuit.Finally,an experimental system is established by integrating the MRDBBPS prototype into a selfdeveloped automotive MR braking test bench(AMRBTB),and several control and braking experiments are performed.This research proposes a RTZRC control algorithm which can significantly increase the tracking accuracy of the brake pedal characteristic curve,particularly at a high pedal velocity.Additionally,the designed MRDBBPS prototype can achieve an effective and favorable control of the AMRBTB with a good repeatability.展开更多
We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multipl...We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multiplexing based on offset QAM(OFDM/OQAM) which is modulated with m-QAM modulations, we demonstrate low-penalty data transmission of OFDM/OQAM 64-QAM, 128-QAM, 256-QAM, and 512-QAM signals in a silicon microring resonator. The observed optical signal-to-noise ratio(OSNR) penalties are 1.7 dB for 64-QAM,1.7 dB for 128-QAM, and 3.1 dB for 256-QAM at a bit-error rate(BER) of 2 × 10^(-3) and 3.3 dB for 512-QAM at a BER of 2 × 10^(-2). The performance degradation due to the wavelength detuning from the microring resonance is evaluated, showing a wavelength range of ~0.48 nm with BER below 2 × 10^(-3). Moreover, we demonstrate data transmission of 191.2-Gbit/s simultaneous eight wavelength channel OFDM/OQAM 256-QAM signals in a silicon microring resonator, achieving OSNR penalties less than 2 dB at a BER of 2 × 10^(-2).展开更多
The Rb（5Dj）＋H2→RbH＋H photochemical reaction has been studied. Rb vapor mixed with H2 is irradiated in a glass cell with 778-nm pulses which populate one of the 52D states by two-photon absorption. Measurements fo...The Rb（5Dj）＋H2→RbH＋H photochemical reaction has been studied. Rb vapor mixed with H2 is irradiated in a glass cell with 778-nm pulses which populate one of the 52D states by two-photon absorption. Measurements for the relative intensities of the atomic fluorescence and the absorption of the RbH product near the axis of the cell yield the rate coefficients for the Rb（5D3/2）＋H2 and Rb（5D5/2）＋H2 reactions, which are （3.6±1.3） ×10^-11 and （1.7±0.6）×10^-11 cm^3/s, respectively. The relative reactivity with H2 for Rb（5D3/2） is higher than that for Rb（5D5/2）.展开更多
基金Supported by the Ministry of Education, Science, Sports, and Culture, Grant-in-aid for Scientific Research (A), (23246150), 2011
文摘Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are presented.The experiment was performed using a scaled model in a tank.In the middle of the scaled model,sacrificial specimens with circular pillar and trough shapes which respectively show different bending moment-displacement characteristics were mounted to compare the dynamic collapse characteristics of the hull girder in waves.The specimens were designed by using finite element(FE)-analysis.Prior to the tank tests,static four-point-bending tests were conducted to detect the load-carrying capacity of the hull girder.It was shown that the load-carrying capacity of a ship including reduction of the capacity after the ultimate strength can be reproduced experimentally by employing the trough type specimens.Tank tests using these specimens were performed under a focused wave in which the hull girder collapses under once and repetitive focused waves.It was shown from the multiple collapse tests that the increase rate of collapse becomes higher once the load-carrying capacity enters the reduction path while the increase rate is lower before reaching the ultimate strength.
基金Supported by the Collaborative Innovation Program of Hefei Science Center,CAS (Grant No.2019HSC-CIP015)the National Natural Science Foundation of China (Grant Nos.11875290,1170529,11875253,and 11975276)+2 种基金the Fundamental Research Funds for the Central Universities (Grant No.WK3420000004)the Anhui Provincial Natural Science Foundation (Grant No.2008085J04)the National Key Research and Development Program of China (Grant No.2019YFE03020004)。
文摘This research applies experimental measurements and NUBEAM,ONETWO and TRANSP modules to investigate the shine-through(ST)loss ratio and beam heating percentage of neutral beam injection on EAST.Measurements and simulations confirm that the ST loss ratio increases linearly with beam energy,and decreases exponentially with plasma density.Moreover,using the multi-step fitting method,we present analytical quantitative expressions of ST loss ratio and beam heating percentage,which are valuable for the high parameter long-pulse experiments of EAST.
基金Supported by National Science Foundation(10402033) Ministry of Education Key Lab.of West Mining and Hazard Control Key Research Founda-tion(04JS19) and Shaanxi Province Natural Science (2003E213)
文摘L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environmental protection were con- cemed greatly. Based on engineering geological environment of L3414 working face and mining factors, the color bore-bole TV inspecting, leakage of drilling fluid monitoring, simulation experiment, numerical computing, in-situ ground stress measurement and subsidence measurement, etal, these programs contribute to the formation of a scientific basis for control water safe mining and normal mining or environmental protection in the condition of existing fully-mechanized mining.
基金Project supported by the Scientific Research and Innovation Team Fund of Universities Affiliated to Sichuan Province(No.2014TD0006)“Research on downhole safety risk and control methods of gas drilling”in Sichuan outstanding young academic technology leader training plan(No.2014JQ0045)Device and software development for quantitative evaluation of low-permeability gas reservoir damages(No.2016ZX05021-004-005).
文摘The damages of different drilling modes to reservoirs are different in types and degrees.In this paper,the geologic characteristics and types of such damages were analyzed.Then,based on the relationship between reservoir pressure and bottom hole flowing pressure corresponding to different drilling modes,the experimental procedures on reservoir damages in three drilling modes(e.g.gas drilling,liquid-based underbalanced drilling and overbalanced drilling)were designed.Finally,damage simulation experiments were conducted on the tight sandstone reservoir cores of the Jurassic Ahe Fm in the Tarim Basin and Triassic Xujiahe Fm in the central Sichuan Basin.It is shown that the underbalanced drilling is beneficial to reservoir protection because of its less damage on reservoir permeability,but it is,to some extent,sensitive to the stress and the empirical formula of stress sensitivity coefficient is obtained;and that the overbalanced drilling has more reservoir damages due to the invasion of solid and liquid phases.After the water saturation of cores rises to the irreducible water saturation,the decline of gas logging permeability speeds up and the damage degree of water lock increases.It is concluded that the laboratory experiment results of reservoir damage are accordant with the reservoir damage characteristics in actual drilling conditions.Therefore,this method reflects accurately the reservoir damage characteristics and can be used as a new experimental evaluation method on reservoir damage in different drilling modes.
文摘In order to investigate the data reliability of the core liquid permeability flow experiment evaluation test results, the uncertainty of the test results was evaluated. First of all, the core liquid permeability evaluation device is used to conduct a complete test according to the industry standard requirements. Then, according to the method in JJF 1059.1-2012 "Evaluation and Expression of Measurement Uncertainty", the known mathematical model is used to accurately identify and calculate each component causing uncertainty in the flow test process. The results show that the uncertainty component caused by mass weighing contributes the most to the combined standard uncertainty, followed by the uncertainty component caused by pressure measurement and the uncertainty component caused by the time flowing through the upper and lower scribing lines of the viscometer, and the accuracy grade of the measuring instrument also has a great influence on the evaluation result of the uncertainty.
文摘The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-tilling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.
文摘This review article provides a thorough assessment of modern and innovative algorithms for text classification through both observational and experimental evaluations.We propose a new classification system,grounded in methodology,to categorize text classification algorithms into an organized structure from general categories down to particular fine-grained techniques.Drawing on more than 100 academic papers from prominent publishers,our extensive review spans a wide range of algorithms,encompassing traditional,deep learning,and emerging approaches.Through observational studies and comparative experiments among various algorithms,techniques,and methodological categories,we offer detailed insights into the area of text classification.The goal of this survey is to assist scholars in choosing the right methods for specific projects while encouraging further advancements in this area.This detailed examination not only contributes to the scholarly conversation on text classification but also seeks to direct future progress by identifying promising avenues for innovation and enhancement.The primary contributions of this article include the sophisticated methodological classification,a thorough review and examination of state-of-the-art algorithms,along with observational and experimental assessments,and a visionary outlook on the future development of text classification methods.
基金Tropical Ocean University 2023 Provincial Key Discipline Construction Project-Business Administration.Project of the National Social Science Foundation:Research on the Cooperation Mechanism and Realisation Path for the Cooperative Development of the Cruise Industry in the Countries Surrounding the South China Sea(19XJY001)Key Laboratory of the Ministry of Culture and Tourism on Data Mining,Monitoring and Early Warning Technology for Island Tourism Resources(KLITRDMM 2022-15).
文摘Cruise value chain is to take the exchange of cruise products and services as the core in a certain spatial scope,and enterprises with core advantages within or between different industries establish associations in accordance with certain technical and economic conditions,so as to realise the multi-dimensional extension and value appreciation of the cruise value chain in the vertical and horizontal links,and ultimately establish a chain-network type of enterprise strategic alliance.This paper tries to analyse the value-added factors of the cruise industry chain by constructing a multi-level hierarchical structural model with reference to the influencing factor analysis methods of relevant literature-DEMATEL(Decision Making Experiment and Evaluation Experiment)and ISM(Interpretative Structural Model).The study shows that the innovation and scale value-added module in the upstream of the cruise industry chain is the core module of value-added of the whole cruise industry chain,and the value-added mainly originates from the design and manufacturing of cruise ships.The middle reaches of the cruise industry chain are mainly cruise operation enterprises,and the specificity of cruise operation determines that its brand value-added is mainly accomplished through the global layout of multinational corporations,and the cruise brand is able to drive the consumption demand and has value-added ability.The downstream value-added of the cruise industry chain is mainly realised through the increase in profits of cruise tourism service products.
基金co-funded by the University of Canterbury,Natural Hazards Platform (NHP)the Ministry of Business,Innovation and Employment (MBIE),New Zealand
文摘This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents.
基金National Natural Science Foundation of China(Grant Nos.52175047 and 51505114)Anhui Provincial Natural Science Foundation of China(Grant No.2008085ME140).
文摘Recent developments have demonstrated that the brake pedal simulator(BPS)is becoming an indispensable apparatus for the break-by-wire systems in future electric vehicles.Its main function is to provide the driver with a comfortable pedal feel to improve braking safety and comfort.This paper presents the development and control of an adjustable BPS,using a disk-type magnetorheological(MR)damper as the passive braking reaction generator to simulate the traditional pedal feel.A detailed description of the mechanical design of the MR damper-based BSP(MRDBBPS)is presented in this paper.Several basic performance experiments on the MRDBBPS prototype are conducted.A returnto-zero(RTZ)algorithm is proposed to avoid hysteresis and improve the repeatability of the pedal force.In addition,an RTZ algorithm-based real-time current-tracking controller(RTZRC)is designed in consideration of the response lag of the coil circuit.Finally,an experimental system is established by integrating the MRDBBPS prototype into a selfdeveloped automotive MR braking test bench(AMRBTB),and several control and braking experiments are performed.This research proposes a RTZRC control algorithm which can significantly increase the tracking accuracy of the brake pedal characteristic curve,particularly at a high pedal velocity.Additionally,the designed MRDBBPS prototype can achieve an effective and favorable control of the AMRBTB with a good repeatability.
基金National Program for Support of Top-Notch Young ProfessionalsNational Natural Science Foundation of China(NSFC)(11574001,11274131,61222502)Program for New Century Excellent Talents in University(NCET)(NCET-11-0182)
文摘We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multiplexing based on offset QAM(OFDM/OQAM) which is modulated with m-QAM modulations, we demonstrate low-penalty data transmission of OFDM/OQAM 64-QAM, 128-QAM, 256-QAM, and 512-QAM signals in a silicon microring resonator. The observed optical signal-to-noise ratio(OSNR) penalties are 1.7 dB for 64-QAM,1.7 dB for 128-QAM, and 3.1 dB for 256-QAM at a bit-error rate(BER) of 2 × 10^(-3) and 3.3 dB for 512-QAM at a BER of 2 × 10^(-2). The performance degradation due to the wavelength detuning from the microring resonance is evaluated, showing a wavelength range of ~0.48 nm with BER below 2 × 10^(-3). Moreover, we demonstrate data transmission of 191.2-Gbit/s simultaneous eight wavelength channel OFDM/OQAM 256-QAM signals in a silicon microring resonator, achieving OSNR penalties less than 2 dB at a BER of 2 × 10^(-2).
基金supported by the National Natural Science Foundation of China under Grant No.10664003
文摘The Rb（5Dj）＋H2→RbH＋H photochemical reaction has been studied. Rb vapor mixed with H2 is irradiated in a glass cell with 778-nm pulses which populate one of the 52D states by two-photon absorption. Measurements for the relative intensities of the atomic fluorescence and the absorption of the RbH product near the axis of the cell yield the rate coefficients for the Rb（5D3/2）＋H2 and Rb（5D5/2）＋H2 reactions, which are （3.6±1.3） ×10^-11 and （1.7±0.6）×10^-11 cm^3/s, respectively. The relative reactivity with H2 for Rb（5D3/2） is higher than that for Rb（5D5/2）.
