作为真力时制表商的标志，ChronoMaster旗舰系列无需赘言，传统与现代的完美融合，它历经似水流年，却依然经典时尚。2008年，ChronoMaster Tourbillon E1 Frimero Day ＆ Night Moonphase，旗舰陀飞轮日夜月相表限量发售。同时，该系...作为真力时制表商的标志，ChronoMaster旗舰系列无需赘言，传统与现代的完美融合，它历经似水流年，却依然经典时尚。2008年，ChronoMaster Tourbillon E1 Frimero Day ＆ Night Moonphase，旗舰陀飞轮日夜月相表限量发售。同时，该系列还将增添又一新贵——Chronomaster Open Grande Date，旗舰开心大日期。展开更多
SiC_(p)/AZ91 composites were prepared by vacuum pressure infiltration.The microstructure,mechanical properties and wear resistance of composite were studied.Results indicated that SiC particles were uniformly distribu...SiC_(p)/AZ91 composites were prepared by vacuum pressure infiltration.The microstructure,mechanical properties and wear resistance of composite were studied.Results indicated that SiC particles were uniformly distributed in the metal matrix and had a good interface bonding with the metal matrix.Mg_(17)Al_(12) preferably precipitated near the SiC particles,and high-density dislocations were induced by the mismatch of the coefficient of thermal expansion(CTE)between the SiC particle and the AZ91 matrix,thereby accelerating the aging precipitation of the matrix.Compared with AZ91 alloy,the addition of SiC particles improves the hardness and compressive strength of the composite,which is mainly due to the load transfer strengthening and grain refinement strengthening mechanisms.Furthermore,a stable support surface-protecting matrix formed during the wear process because of the excellent wear resistance of SiC.展开更多
Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar...Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar to the system has been considered.Our method and that presented by Konishi et al.[Phys.Rev.E 60 (1999) 4000]are compared.Although both the methods could suppress the traffic jam,the simulation results show that the temporalbehavior obtained by ours is better than that proposed by the Konishi's et al.The simulation results are consistent withthe theoretical analysis.展开更多
To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in the western Arctic Ocean,234 Th238 U disequilibrium was applied during the second Chinese Natio...To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in the western Arctic Ocean,234 Th238 U disequilibrium was applied during the second Chinese National Arctic Research Expedition (July 15-September 26,2003).The POC export fluxes are estimated from the measured profiles of the 234 Th/238 U activity ratios and the POC/PTh ratios.The average residence times of the particulate and dissolved 234 Th in the euphotic zone are 33 d and 121 d,and their average export fluxes are 480 dpm/m 2 d and 760 dpm/m 2 d,respectively.The scavenging and removal processes of particle reactive elements are active in the upper layer of the Chukchi Sea.The average residence time of 234 Th increases from shelf to basin,while the export fluxes of 234 Th decrease.The estimated POC export fluxes from the euphotic zone vary from 2.1 to 20.3 mmol/m 2 d,indicating that the western Arctic Ocean is an important carbon sink in summer due to efficient biological pump.展开更多
Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the...Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.展开更多
文摘作为真力时制表商的标志，ChronoMaster旗舰系列无需赘言，传统与现代的完美融合，它历经似水流年，却依然经典时尚。2008年，ChronoMaster Tourbillon E1 Frimero Day ＆ Night Moonphase，旗舰陀飞轮日夜月相表限量发售。同时，该系列还将增添又一新贵——Chronomaster Open Grande Date，旗舰开心大日期。
基金financial supports from the National Natural Science Foundation of China(Nos.U1810208,51575230)the Science and Technology Development Program of Jilin Province,China(No.20190302059GX)。
文摘SiC_(p)/AZ91 composites were prepared by vacuum pressure infiltration.The microstructure,mechanical properties and wear resistance of composite were studied.Results indicated that SiC particles were uniformly distributed in the metal matrix and had a good interface bonding with the metal matrix.Mg_(17)Al_(12) preferably precipitated near the SiC particles,and high-density dislocations were induced by the mismatch of the coefficient of thermal expansion(CTE)between the SiC particle and the AZ91 matrix,thereby accelerating the aging precipitation of the matrix.Compared with AZ91 alloy,the addition of SiC particles improves the hardness and compressive strength of the composite,which is mainly due to the load transfer strengthening and grain refinement strengthening mechanisms.Furthermore,a stable support surface-protecting matrix formed during the wear process because of the excellent wear resistance of SiC.
基金Supported by the National Natural Science Foundation of China under Grant Nos.2006CB705500,10532060,and 60904068the Natural Science Foundation of NingBo under Grant Nos.2009B21003,2009A610154,2009A610014K.C.Wong Magna Fund in Ningbo University
文摘Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar to the system has been considered.Our method and that presented by Konishi et al.[Phys.Rev.E 60 (1999) 4000]are compared.Although both the methods could suppress the traffic jam,the simulation results show that the temporalbehavior obtained by ours is better than that proposed by the Konishi's et al.The simulation results are consistent withthe theoretical analysis.
基金Supported by the National Natural Science Foundation of China (No.40531007)the China Action Plan of the International Polar Year (Nos.2009DFA22920 and 2008Po5040014-03)+1 种基金the International Science and Technology Cooperation (Nos. 2008DFA20420 and 2009DFA22920)the Polar Atmospheric Environment Remote Sensing Monitoring Technique of the National High Technology Research and DevelopmentProgram of China (863 Program) (No. N2008DFA20420)
文摘To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in the western Arctic Ocean,234 Th238 U disequilibrium was applied during the second Chinese National Arctic Research Expedition (July 15-September 26,2003).The POC export fluxes are estimated from the measured profiles of the 234 Th/238 U activity ratios and the POC/PTh ratios.The average residence times of the particulate and dissolved 234 Th in the euphotic zone are 33 d and 121 d,and their average export fluxes are 480 dpm/m 2 d and 760 dpm/m 2 d,respectively.The scavenging and removal processes of particle reactive elements are active in the upper layer of the Chukchi Sea.The average residence time of 234 Th increases from shelf to basin,while the export fluxes of 234 Th decrease.The estimated POC export fluxes from the euphotic zone vary from 2.1 to 20.3 mmol/m 2 d,indicating that the western Arctic Ocean is an important carbon sink in summer due to efficient biological pump.
文摘Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.
