A mode for the periodicity and weakening surge in semi-insulating GaAs photoconductive semiconductor switches is proposed based on the transferred-electron effect. It is shown that the periodicity and weakening surge ...A mode for the periodicity and weakening surge in semi-insulating GaAs photoconductive semiconductor switches is proposed based on the transferred-electron effect. It is shown that the periodicity and weakening surge is caused by the interaction between the self-excitation of the resonant circuit and transferred electron oscillation of the switch. The bias electric field （larger than Gunn threshold） across the switch is modulated by the AC elec-tric field,when the instantaneous bias electric field E is swinging below Gunn electric field threshold ET but grea-ter than the sustaining field Es （the minimum electric field required to support the domain） at the time of the do-main reaching the anode, and then the delayed-dipole domain mode of switch is obtained. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length prod-uct of 10^12 cm^-2,and the semi-insulating GaAs photoconductive semiconductor switch is essentially a type of pho-ton-activated charge domain device.展开更多
Considering the delay effect of initial lining and revising the Winkler elastic foundation model,an analytical approach based on Pasternak elastic foundation beam theory for pipe roof reinforcement was put forward. Wi...Considering the delay effect of initial lining and revising the Winkler elastic foundation model,an analytical approach based on Pasternak elastic foundation beam theory for pipe roof reinforcement was put forward. With the example of a certain tunnel excavation,the comparison of the values of longitudinal strain of reinforcing pipe between field monitoring and analytical approach was made. The results indicate that Pasternak model,which considers a more realistic hypothesis in the elastic soil than Winkler model,gives more accurate calculation and agrees better with the result of field monitoring. The difference of calculation results between these two models is about 7%,and Pasternak model is proved to be a better way to study the reinforcement mechanism and improve design practice. The calculation results also reveal that the reinforcing pipes act as levers,which increases longitudinal load transfer to an unexcavated area,and consequently decreases deformation and increases face stability.展开更多
OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cel...OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cell line （MIA PaCa-2） in the lateral of the right lower extremity of the athymic mouse to grow transplantation tumor. While the median diameter of transplantation tumor reached 10 mm approximately, the animals were randomly divided into 7 groups （6 animals per group） and irradiation by different dose in one fixed with consciousness for fraction （0, 2, 5, 10, 17, 25, 35 Gy）. All were kept on to be bred for observation of the change in gross tumor volume, calculation of delayed growth time and delayed growth curve. RESULTS With increased dose per fraction, cutaneous reaction on the neoplasma surface of the animal, which was mainly moist yellow effusion was more and more severe. When dosage is less than 10 Gy, all animals showed similar effects, that＇s the delayed tumor growth was not obvious. Tumors receiving more than 10 Gy in one fraction showed very good biological effect and the delayed tumor growth was obviously related to dosage. The difference in delayed tumor growth between the 2 groups was statistically significant. The delayed tumor growth time in 10, 17, 25 Gy group was respectively 3 weeks, 6 weeks and more. CONCLUSION The biological effect of the model which applies high single-dose irradiation （more than 10 Gy in one fraction） was very good. The effect of delayed tumor growth was obviously related to the dosage after transplantation tumor was radiated. Because of its higher dose per fraction and biological effects, the model of high single-dose irradiation can get better clinical effects.展开更多
Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orc...Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orchestration with dynamic latency simulated in Colored PetriNets （CPNs）. First, we extend the CPN to Web Service Composition Orchestration Network System （WS-CONS） for the description of dynamic latency in service orchestration. Secondly, with simulated dynamic latency, a buffer-limited policy and admittance-control policy are designed in WS- CONS and implemented on CPN Tools. In the buffer-limited policy, the passing messages would be discarded if the node capacity is not adequate. In the admittance-control policy, the ability of a message entering the system depends on the number of messages concurrently flowing in the system. This helps to enhance the success rate of message passing. Finally, the system performance is evaluated through running models in CPN Tools. Simulated results show that the dynamic latency plays an important role in the system throughput and response latency. This simulation helps system designers to quickly make proper compromises at low cost.展开更多
文摘A mode for the periodicity and weakening surge in semi-insulating GaAs photoconductive semiconductor switches is proposed based on the transferred-electron effect. It is shown that the periodicity and weakening surge is caused by the interaction between the self-excitation of the resonant circuit and transferred electron oscillation of the switch. The bias electric field （larger than Gunn threshold） across the switch is modulated by the AC elec-tric field,when the instantaneous bias electric field E is swinging below Gunn electric field threshold ET but grea-ter than the sustaining field Es （the minimum electric field required to support the domain） at the time of the do-main reaching the anode, and then the delayed-dipole domain mode of switch is obtained. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length prod-uct of 10^12 cm^-2,and the semi-insulating GaAs photoconductive semiconductor switch is essentially a type of pho-ton-activated charge domain device.
基金Project(IRT0518) supported by the Program of Innovative Research Team of Ministry of Education of China
文摘Considering the delay effect of initial lining and revising the Winkler elastic foundation model,an analytical approach based on Pasternak elastic foundation beam theory for pipe roof reinforcement was put forward. With the example of a certain tunnel excavation,the comparison of the values of longitudinal strain of reinforcing pipe between field monitoring and analytical approach was made. The results indicate that Pasternak model,which considers a more realistic hypothesis in the elastic soil than Winkler model,gives more accurate calculation and agrees better with the result of field monitoring. The difference of calculation results between these two models is about 7%,and Pasternak model is proved to be a better way to study the reinforcement mechanism and improve design practice. The calculation results also reveal that the reinforcing pipes act as levers,which increases longitudinal load transfer to an unexcavated area,and consequently decreases deformation and increases face stability.
文摘OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cell line （MIA PaCa-2） in the lateral of the right lower extremity of the athymic mouse to grow transplantation tumor. While the median diameter of transplantation tumor reached 10 mm approximately, the animals were randomly divided into 7 groups （6 animals per group） and irradiation by different dose in one fixed with consciousness for fraction （0, 2, 5, 10, 17, 25, 35 Gy）. All were kept on to be bred for observation of the change in gross tumor volume, calculation of delayed growth time and delayed growth curve. RESULTS With increased dose per fraction, cutaneous reaction on the neoplasma surface of the animal, which was mainly moist yellow effusion was more and more severe. When dosage is less than 10 Gy, all animals showed similar effects, that＇s the delayed tumor growth was not obvious. Tumors receiving more than 10 Gy in one fraction showed very good biological effect and the delayed tumor growth was obviously related to dosage. The difference in delayed tumor growth between the 2 groups was statistically significant. The delayed tumor growth time in 10, 17, 25 Gy group was respectively 3 weeks, 6 weeks and more. CONCLUSION The biological effect of the model which applies high single-dose irradiation （more than 10 Gy in one fraction） was very good. The effect of delayed tumor growth was obviously related to the dosage after transplantation tumor was radiated. Because of its higher dose per fraction and biological effects, the model of high single-dose irradiation can get better clinical effects.
基金This paper was supported by the National Natural Science Foundation of China under Grants No.61170053,No.61101214,No.61100205，the National High-Tech Research and Development Plan of China under Grant No.2012AA010902-1，the Natural Science Foundation of Beijing under Grant No.4112027，Special Project of National CAS Union-The High Performace Cloud Service Platform for Enterprise Creative Computing
文摘Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orchestration with dynamic latency simulated in Colored PetriNets （CPNs）. First, we extend the CPN to Web Service Composition Orchestration Network System （WS-CONS） for the description of dynamic latency in service orchestration. Secondly, with simulated dynamic latency, a buffer-limited policy and admittance-control policy are designed in WS- CONS and implemented on CPN Tools. In the buffer-limited policy, the passing messages would be discarded if the node capacity is not adequate. In the admittance-control policy, the ability of a message entering the system depends on the number of messages concurrently flowing in the system. This helps to enhance the success rate of message passing. Finally, the system performance is evaluated through running models in CPN Tools. Simulated results show that the dynamic latency plays an important role in the system throughput and response latency. This simulation helps system designers to quickly make proper compromises at low cost.
