Operators suffer much diffieulty in manipulating miero-size objects without the assistance of friendly interfaces due to the scaling effects in micro worht. The paper presented a general framework for mieromanipulatio...Operators suffer much diffieulty in manipulating miero-size objects without the assistance of friendly interfaces due to the scaling effects in micro worht. The paper presented a general framework for mieromanipulation robot hased on virtual reality technology. With the framework we brought forward a FDH (Fixed Direction Hulls) based hounding box method to handle the eollision ,teteetion of the peg-in-hole mieroassembly. The eollision response model for the collision between micro needle and hole was presented. The virtual three and corresponding displacement were calculated with the model of bending deformation and pressing ,teformation. Experiments verify the validity of collision response model.展开更多
The broad application of virtual reality (VR) to medicine has been of great value. The virtual surgery is one of technically difficult applications. With the expansion of the increasingly fine and complicated ear micr...The broad application of virtual reality (VR) to medicine has been of great value. The virtual surgery is one of technically difficult applications. With the expansion of the increasingly fine and complicated ear microsurgery, new methods are required to train the doctors. It is necessary and of practical significance to apply VR to the ear micro-operation, which is a functional operation with high precision and great difficulties. In this article, medical VR applications were reviewed. The application of VR to the ear microsurgery was discussed and the virtual ear microsurgery system was designed.展开更多
The genomic resources of Porphyra yezoensis expressed sequence tags (ESTs) were utilized to identify simple sequence repeats (SSRs), or microsatellites. This method took the advantage of using ESTs and microsatellites...The genomic resources of Porphyra yezoensis expressed sequence tags (ESTs) were utilized to identify simple sequence repeats (SSRs), or microsatellites. This method took the advantage of using ESTs and microsatellites either for the establishment of gene identities or for the acquisition of high polymorphism. The microsatellites can be used as gene markers when microsatellites are tagged to genes. Revealed by bioinformatics analysis, 1 162 out of 21 954 ESTs contained microsatellites and cluster analysis indi- cated that 984 of these ESTs fell into 112 contigs, while the other 178 ESTs were singletons. A total of 290 unique SSR-containing genes were identified. The AAC SSRs were the most populous type of microsatellites. GC-rich microsatellites were predominant among all the microsatellites.展开更多
The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete elem...The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete element method.A randomly generating algorithm was proposed to capture the three-dimensional irregular shape of coarse aggregate.And then,modeling algorithm and method for graded aggregates were built.Based on the combination of modeling of coarse aggregates,asphalt mastic and air voids,three-dimensional virtual sample of asphalt mixture was modeled by using PFC^(3D).Virtual tests for penetration test of aggregate and uniaxial creep test of asphalt mixture were built and conducted by using PFC^(3D).By comparison of the testing results between virtual tests and actual laboratory tests,the validity of the microstructure modeling and virtual test built in this study was verified.Additionally,compared with laboratory test,the virtual test is easier to conduct and has less variability.It is proved that microstructure modeling and virtual test based on three-dimensional discrete element method is a promising way to conduct research of asphalt mixture.展开更多
Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management me...Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management mechanism between the operating system and user programs. This paper analyzes the tradeoffs considered in the MMU design of Unity 11 CPU of Peking University, and introduces in detail the solution of pure hardware table walking with two level page table organization. The implementation takes care of required operations and high performances needed by modern operating systems and low costs needed by embedded systems. This solution has been silicon proven, and successfully porting the Linux 2.4.17 kernel, the XWindow system, GNOME and most application software onto the Unity platform.展开更多
The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking en...The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking energy feedback unit and battery energy storage unit is proposed,which provides green power for the station.In order to suppress the fluctuation of photovoltaic power generation and the intermittence of regenerative braking feedback energy,the energy management mode of microgrid is designed according to the illumination situation,braking energy feedback situation,battery state of charge and so on.In addition,a coordination control method based on virtual synchronous generator(VSG)is proposed to realize smooth switching among modes.Finally,the proposed energy management and coordination control method for elevated station microgrid is verified by Matlab/Simulink.The results show that the elevated station microgrid can operate safely and reliably under various energy management modes and realize smooth switching among modes.展开更多
To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid...To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid system is studied,including diesel generators,photovoltaic power generation system,wind power generation system and energy storage unit.Meanwhile,in order to realize the voltage and frequency stability control of AC bus of multisource microgrid,the virtual synchronous generator technology is introduced into the energy storage unit,and the charge and discharge control of the energy storage battery are simulated as the control behavior characteristics of synchronous motors,so as to provide damping and inertia support for the microgrid.The operation mode and control principle of each energy subsystem are expounded and analyzed.The algorithm principle of virtual synchronous generator and the control method of energy storage unit are given.Then,the working modes of the microgrid system under different environmental conditions are analyzed,and the multi-source microgrid system simulation model is built based on MATLAB/Simulink.The simulation results show that the microgrid system can run stably under different working modes and the energy storage unit using the virtual synchronous generator technology can provide good voltage and frequency support for the microgrid system.Finally,experiments verify the supporting function of energy storage unit on the voltage and frequency of the microgrid system.展开更多
We propose a potentially practical scheme for efcient generation of entanglement with two nitrogen-vacancy centers(NVC)coupled to a whispering-gallery mode cavity.By virtue of the virtual-photon-excitation,the entangl...We propose a potentially practical scheme for efcient generation of entanglement with two nitrogen-vacancy centers(NVC)coupled to a whispering-gallery mode cavity.By virtue of the virtual-photon-excitation,the entanglement with two separate NVC can be produced in a deterministic way.The required operations are very close to the capabilities of current experimental techniques.The efects of decoherence induced by the cavity decay and the atomic spontaneous decay are also investigated.展开更多
Objective: To compare the effects between electroacupuncture (EA) at Chize (LU 5, the He-Sea point of the Lung Meridian) and Shangjuxu (ST 37, the lower He-Sea point of the large intestine) in rats with ulcerat...Objective: To compare the effects between electroacupuncture (EA) at Chize (LU 5, the He-Sea point of the Lung Meridian) and Shangjuxu (ST 37, the lower He-Sea point of the large intestine) in rats with ulcerative colitis (UC) on the variations of mesenteric microcirculation and vasoactive intestinal peptide (VIP) in the colon, lung, and hypothalamus. The relative specificity of acupoints was also explored. Methods: A total of 28 male Wistar rats were randomized into a normal group, a model group, a Chize (LU 5) group and a Shangjuxu (ST 37) group, 7 rats in each group. The UC model was established by enema with acetic acid. Since the third day after modeling, rats in the Chize (LU 5) group and Shangjuxu (ST 37) group respectively received EA at Chize (LU 5) and Shangjuxu (ST 37), 1S min each time for successive 7 d. The variations of mesenteric microvascular calibers and blood flow status were observed by a microcirculation microscopic tester; VIP in the colon, lung and hypothalamus was measured by radioimmunoassay. Results: Compared with the normal group, the mesenteric microvascular calibers were significantly expanded in the model group (P〈0.05); there was no significant difference between the model group and Chize (LU 5) group (P〉0.05); compared with the model group and Chize (LU 5) group, the calibers were obviously shrunk in Shangjuxu (ST 37) group (P〈0.05). The four groups showed no significant inter-group differences in comparing blood flow status (P〉0.05). The colonic VIP levels in the model group and Chize (LU 5) group were significantly higher than that in the normal group (P〈0.01, P〈0.05); the VIP level in Shangjuxu (ST 37) group was markedly lower than that in the model group (P〈0.01). There were no significant differences among the four groups in comparing VIP level in lung and hypothalamus (P〉0.05). Conclusion: The effects of Chize (LU 5) and Shangjuxu (ST 37) were different in treating UC. Shangjuxu (ST 37) showed a more significant efficacy in down-regulating VIP in the colon and regulating mesenteric microcirculation, while the effects of Chize (LU 5) were not obvious.展开更多
文摘Operators suffer much diffieulty in manipulating miero-size objects without the assistance of friendly interfaces due to the scaling effects in micro worht. The paper presented a general framework for mieromanipulation robot hased on virtual reality technology. With the framework we brought forward a FDH (Fixed Direction Hulls) based hounding box method to handle the eollision ,teteetion of the peg-in-hole mieroassembly. The eollision response model for the collision between micro needle and hole was presented. The virtual three and corresponding displacement were calculated with the model of bending deformation and pressing ,teformation. Experiments verify the validity of collision response model.
基金The Scientific Research Fund of ShanghaiScience Committee( 0 3 411980 8) and the Science and TechnologySpecial Fund of Pudong New District( PKJ2 0 0 3 -4 1)
文摘The broad application of virtual reality (VR) to medicine has been of great value. The virtual surgery is one of technically difficult applications. With the expansion of the increasingly fine and complicated ear microsurgery, new methods are required to train the doctors. It is necessary and of practical significance to apply VR to the ear micro-operation, which is a functional operation with high precision and great difficulties. In this article, medical VR applications were reviewed. The application of VR to the ear microsurgery was discussed and the virtual ear microsurgery system was designed.
文摘The genomic resources of Porphyra yezoensis expressed sequence tags (ESTs) were utilized to identify simple sequence repeats (SSRs), or microsatellites. This method took the advantage of using ESTs and microsatellites either for the establishment of gene identities or for the acquisition of high polymorphism. The microsatellites can be used as gene markers when microsatellites are tagged to genes. Revealed by bioinformatics analysis, 1 162 out of 21 954 ESTs contained microsatellites and cluster analysis indi- cated that 984 of these ESTs fell into 112 contigs, while the other 178 ESTs were singletons. A total of 290 unique SSR-containing genes were identified. The AAC SSRs were the most populous type of microsatellites. GC-rich microsatellites were predominant among all the microsatellites.
基金Project(51378006) supported by National Natural Science Foundation of ChinaProject(141076) supported by Huoyingdong Foundation of the Ministry of Education of China+1 种基金Project(2242015R30027) supported by Excellent Young Teacher Program of Southeast University,ChinaProject(BK20140109) supported by the Natural Science Foundation of Jiangsu Province,China
文摘The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete element method.A randomly generating algorithm was proposed to capture the three-dimensional irregular shape of coarse aggregate.And then,modeling algorithm and method for graded aggregates were built.Based on the combination of modeling of coarse aggregates,asphalt mastic and air voids,three-dimensional virtual sample of asphalt mixture was modeled by using PFC^(3D).Virtual tests for penetration test of aggregate and uniaxial creep test of asphalt mixture were built and conducted by using PFC^(3D).By comparison of the testing results between virtual tests and actual laboratory tests,the validity of the microstructure modeling and virtual test built in this study was verified.Additionally,compared with laboratory test,the virtual test is easier to conduct and has less variability.It is proved that microstructure modeling and virtual test based on three-dimensional discrete element method is a promising way to conduct research of asphalt mixture.
文摘Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management mechanism between the operating system and user programs. This paper analyzes the tradeoffs considered in the MMU design of Unity 11 CPU of Peking University, and introduces in detail the solution of pure hardware table walking with two level page table organization. The implementation takes care of required operations and high performances needed by modern operating systems and low costs needed by embedded systems. This solution has been silicon proven, and successfully porting the Linux 2.4.17 kernel, the XWindow system, GNOME and most application software onto the Unity platform.
基金National Natural Science Foundation of China(No.51367010)Science and Technology Program of Gansu Province(No.17JR5RA083)Program for Excellent Team of Scientific Research in Lanzhou Jiaotong University(No.201701)
文摘The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking energy feedback unit and battery energy storage unit is proposed,which provides green power for the station.In order to suppress the fluctuation of photovoltaic power generation and the intermittence of regenerative braking feedback energy,the energy management mode of microgrid is designed according to the illumination situation,braking energy feedback situation,battery state of charge and so on.In addition,a coordination control method based on virtual synchronous generator(VSG)is proposed to realize smooth switching among modes.Finally,the proposed energy management and coordination control method for elevated station microgrid is verified by Matlab/Simulink.The results show that the elevated station microgrid can operate safely and reliably under various energy management modes and realize smooth switching among modes.
基金supported by the Science and Technology Research&Development Project of China Construction Second Engineering Bureau Ltd.(No.91110000100024296D180009)。
文摘To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid system is studied,including diesel generators,photovoltaic power generation system,wind power generation system and energy storage unit.Meanwhile,in order to realize the voltage and frequency stability control of AC bus of multisource microgrid,the virtual synchronous generator technology is introduced into the energy storage unit,and the charge and discharge control of the energy storage battery are simulated as the control behavior characteristics of synchronous motors,so as to provide damping and inertia support for the microgrid.The operation mode and control principle of each energy subsystem are expounded and analyzed.The algorithm principle of virtual synchronous generator and the control method of energy storage unit are given.Then,the working modes of the microgrid system under different environmental conditions are analyzed,and the multi-source microgrid system simulation model is built based on MATLAB/Simulink.The simulation results show that the microgrid system can run stably under different working modes and the energy storage unit using the virtual synchronous generator technology can provide good voltage and frequency support for the microgrid system.Finally,experiments verify the supporting function of energy storage unit on the voltage and frequency of the microgrid system.
基金supported by the National Natural Science Foundation of China(Grant Nos.10874122 and 11372122)the Program for Excellent Talents at the University of Guangdong Province(Guangdong Teacher Letter[1010]No.79)
文摘We propose a potentially practical scheme for efcient generation of entanglement with two nitrogen-vacancy centers(NVC)coupled to a whispering-gallery mode cavity.By virtue of the virtual-photon-excitation,the entanglement with two separate NVC can be produced in a deterministic way.The required operations are very close to the capabilities of current experimental techniques.The efects of decoherence induced by the cavity decay and the atomic spontaneous decay are also investigated.
基金supported by the Independent Subject Project of Beijing University of Chinese Medicine for Postgraduate~~
文摘Objective: To compare the effects between electroacupuncture (EA) at Chize (LU 5, the He-Sea point of the Lung Meridian) and Shangjuxu (ST 37, the lower He-Sea point of the large intestine) in rats with ulcerative colitis (UC) on the variations of mesenteric microcirculation and vasoactive intestinal peptide (VIP) in the colon, lung, and hypothalamus. The relative specificity of acupoints was also explored. Methods: A total of 28 male Wistar rats were randomized into a normal group, a model group, a Chize (LU 5) group and a Shangjuxu (ST 37) group, 7 rats in each group. The UC model was established by enema with acetic acid. Since the third day after modeling, rats in the Chize (LU 5) group and Shangjuxu (ST 37) group respectively received EA at Chize (LU 5) and Shangjuxu (ST 37), 1S min each time for successive 7 d. The variations of mesenteric microvascular calibers and blood flow status were observed by a microcirculation microscopic tester; VIP in the colon, lung and hypothalamus was measured by radioimmunoassay. Results: Compared with the normal group, the mesenteric microvascular calibers were significantly expanded in the model group (P〈0.05); there was no significant difference between the model group and Chize (LU 5) group (P〉0.05); compared with the model group and Chize (LU 5) group, the calibers were obviously shrunk in Shangjuxu (ST 37) group (P〈0.05). The four groups showed no significant inter-group differences in comparing blood flow status (P〉0.05). The colonic VIP levels in the model group and Chize (LU 5) group were significantly higher than that in the normal group (P〈0.01, P〈0.05); the VIP level in Shangjuxu (ST 37) group was markedly lower than that in the model group (P〈0.01). There were no significant differences among the four groups in comparing VIP level in lung and hypothalamus (P〉0.05). Conclusion: The effects of Chize (LU 5) and Shangjuxu (ST 37) were different in treating UC. Shangjuxu (ST 37) showed a more significant efficacy in down-regulating VIP in the colon and regulating mesenteric microcirculation, while the effects of Chize (LU 5) were not obvious.