A series of experimental tests of passive VIV suppression of an inclined flexible cylinder with round-sectioned helical strakes were carried out in a towing tank. During the tests, the cylinder models fitted with and ...A series of experimental tests of passive VIV suppression of an inclined flexible cylinder with round-sectioned helical strakes were carried out in a towing tank. During the tests, the cylinder models fitted with and without helical strakes were towed along the tank. The towing velocity ranged from 0.05 to 1.0 m/s with an interval of 0.05 m/s.Four different yaw angles(a=0°, 15°, 30° and 45°), defined as the angle between the axis of the cylinder and the plane orthogonal of the oncoming flow, were selected in the experiment. The main purpose of present experimental work is to further investigate the VIV suppression effectiveness of round-sectioned helical strakes on the inclined flexible cylinder. The VIV responses of the smooth cylinder and the cylinder with square-sectioned strakes under the same experimental condition were also presented for comparison. The experimental results indicated that the roundsectioned strake basically had a similar effect on VIV suppression compared with the square-sectioned one, and both can significantly reduce the VIV of the vertical cylinder which corresponded to the case of a=0°. But with the increase of yaw angle, the VIV suppression effectiveness of both round-and square-section strakes deteriorated dramatically, the staked cylinder even had a much stronger vibration than the smooth one did in the in-line(IL)direction.展开更多
This research reveals the dependency of floating point computation in nonlinear dynamical systems on machine precision and step-size by applying a multiple-precision approach in the Lorenz nonlinear equations. The pap...This research reveals the dependency of floating point computation in nonlinear dynamical systems on machine precision and step-size by applying a multiple-precision approach in the Lorenz nonlinear equations. The paper also demoastrates the procedures for obtaining a real numerical solution in the Lorenz system with long-time integration and a new multiple-precision-based approach used to identify the maximum effective computation time （MECT） and optimal step-size （OS）. In addition, the authors introduce how to analyze round-off error in a long-time integration in some typical cases of nonlinear systems and present its approximate estimate expression.展开更多
Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phas...Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phase-encoded Bennett-Brassard 1984 protocol（PE-BB84） to the RRDPS,this paper presents another quantum key distribution protocol called round-robin differential quadrature phase-shift（RRDQPS） quantum key distribution.Regarding a train of many pulses as a single packet,the sender modulates the phase of each pulse by one of {0,π/2,π,3π/2},then the receiver measures each packet with a Mach-Zehnder interferometer having a phase basis of 0 or π/2.The RRDQPS protocol can be implemented with essential similar hardware to the PE-BB84,so it has great compatibility with the current quantum system.Here we analyze the security of the RRDQPS protocol against the intercept-resend attack and the beam-splitting attack.Results show that the proposed protocol inherits the advantages arising from the simplicity of the RRDPS protocol and is more robust against these attacks than the original protocol.展开更多
In this paper, we proposed the scheme for a passive round-robin differential-phase-shift quantum key distribution（RRDPS-QKD） set-up based on the principle of Hong–Ou–Mandel interference. Our scheme requires two le...In this paper, we proposed the scheme for a passive round-robin differential-phase-shift quantum key distribution（RRDPS-QKD） set-up based on the principle of Hong–Ou–Mandel interference. Our scheme requires two legitimate parties to prepare their signal state with two different non-orthogonal bases instead of single in original protocol. Incorporating this characteristic, we establish the level of security of our protocol under the intercept-resend attack and demonstrate its detector-flaw-immune feature. Furthermore, we show that our scheme not only inherits the merit of better tolerance of bit errors and finite-sized-key effects but can be implemented using hardware similar to the measurement device independent QKD（MDI-QKD）. This ensures good compatibility with the current commonly used quantum system.展开更多
Objective:To observe the clinical effect on superior cluneal nerve(SCN)entrapment syndrome treated with the release technique of long round-sharp needle.Methods:The syndrome differentiation based on meridian muscle re...Objective:To observe the clinical effect on superior cluneal nerve(SCN)entrapment syndrome treated with the release technique of long round-sharp needle.Methods:The syndrome differentiation based on meridian muscle region was adopted.The release technique of the long round-sharp needle was used at the lesions of meridian tendon region,Yāoyícì(Beside Yaoyi)and the transverse process of the third lumbar vertebra in 34 patients with SCN entrapment syndrome.The treatment was given once a week,4 treatments made one course.After one course treatment,the therapeutic effect was observed.The results of pain rating index(PRI),the visual analogy scores(VAS)and the present pain intensity(PPI)were compared before and after treatment.Results:Of 34 patients,28 cases(82%)were cured,6 cases(18%)effective and 0 case(0%)failed.The total effective rate was 100%.The scores of PRI,VAS and PPI were(10.78±1.98),(5.98±1.19)and(3.91±1.68)successively in 34 cases before treatment and they were(1.98±1.79),(0.89±1.12)and(0.82±0.79)after treatment.The score of every evaluation scale after treatment was lower significantly than that before treatment(all P<0.01).Conclusion:The release technique of long round-sharp needle achieves the satisfactory clinical effect on SCN entrapment syndrome.Hence,this therapeutic method deserves to be promoted.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51479135 and 51679167)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51621092)
文摘A series of experimental tests of passive VIV suppression of an inclined flexible cylinder with round-sectioned helical strakes were carried out in a towing tank. During the tests, the cylinder models fitted with and without helical strakes were towed along the tank. The towing velocity ranged from 0.05 to 1.0 m/s with an interval of 0.05 m/s.Four different yaw angles(a=0°, 15°, 30° and 45°), defined as the angle between the axis of the cylinder and the plane orthogonal of the oncoming flow, were selected in the experiment. The main purpose of present experimental work is to further investigate the VIV suppression effectiveness of round-sectioned helical strakes on the inclined flexible cylinder. The VIV responses of the smooth cylinder and the cylinder with square-sectioned strakes under the same experimental condition were also presented for comparison. The experimental results indicated that the roundsectioned strake basically had a similar effect on VIV suppression compared with the square-sectioned one, and both can significantly reduce the VIV of the vertical cylinder which corresponded to the case of a=0°. But with the increase of yaw angle, the VIV suppression effectiveness of both round-and square-section strakes deteriorated dramatically, the staked cylinder even had a much stronger vibration than the smooth one did in the in-line(IL)direction.
基金This study was supported by the National Key Basic Research and Development Project of China 2004CB418303 the National Natural Science foundation of China under Grant Nos. 40305012 and 40475027Jiangsu Key Laboratory of Meteorological Disaster KLME0601.
文摘This research reveals the dependency of floating point computation in nonlinear dynamical systems on machine precision and step-size by applying a multiple-precision approach in the Lorenz nonlinear equations. The paper also demoastrates the procedures for obtaining a real numerical solution in the Lorenz system with long-time integration and a new multiple-precision-based approach used to identify the maximum effective computation time （MECT） and optimal step-size （OS）. In addition, the authors introduce how to analyze round-off error in a long-time integration in some typical cases of nonlinear systems and present its approximate estimate expression.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61505261 and 11304397)the National Basic Research Program of China(Grant No.2013CB338002)
文摘Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phase-encoded Bennett-Brassard 1984 protocol（PE-BB84） to the RRDPS,this paper presents another quantum key distribution protocol called round-robin differential quadrature phase-shift（RRDQPS） quantum key distribution.Regarding a train of many pulses as a single packet,the sender modulates the phase of each pulse by one of {0,π/2,π,3π/2},then the receiver measures each packet with a Mach-Zehnder interferometer having a phase basis of 0 or π/2.The RRDQPS protocol can be implemented with essential similar hardware to the PE-BB84,so it has great compatibility with the current quantum system.Here we analyze the security of the RRDQPS protocol against the intercept-resend attack and the beam-splitting attack.Results show that the proposed protocol inherits the advantages arising from the simplicity of the RRDPS protocol and is more robust against these attacks than the original protocol.
基金Project supported by the Fund from the State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)(Grant No.IPOC2017ZT0)
文摘In this paper, we proposed the scheme for a passive round-robin differential-phase-shift quantum key distribution（RRDPS-QKD） set-up based on the principle of Hong–Ou–Mandel interference. Our scheme requires two legitimate parties to prepare their signal state with two different non-orthogonal bases instead of single in original protocol. Incorporating this characteristic, we establish the level of security of our protocol under the intercept-resend attack and demonstrate its detector-flaw-immune feature. Furthermore, we show that our scheme not only inherits the merit of better tolerance of bit errors and finite-sized-key effects but can be implemented using hardware similar to the measurement device independent QKD（MDI-QKD）. This ensures good compatibility with the current commonly used quantum system.
文摘Objective:To observe the clinical effect on superior cluneal nerve(SCN)entrapment syndrome treated with the release technique of long round-sharp needle.Methods:The syndrome differentiation based on meridian muscle region was adopted.The release technique of the long round-sharp needle was used at the lesions of meridian tendon region,Yāoyícì(Beside Yaoyi)and the transverse process of the third lumbar vertebra in 34 patients with SCN entrapment syndrome.The treatment was given once a week,4 treatments made one course.After one course treatment,the therapeutic effect was observed.The results of pain rating index(PRI),the visual analogy scores(VAS)and the present pain intensity(PPI)were compared before and after treatment.Results:Of 34 patients,28 cases(82%)were cured,6 cases(18%)effective and 0 case(0%)failed.The total effective rate was 100%.The scores of PRI,VAS and PPI were(10.78±1.98),(5.98±1.19)and(3.91±1.68)successively in 34 cases before treatment and they were(1.98±1.79),(0.89±1.12)and(0.82±0.79)after treatment.The score of every evaluation scale after treatment was lower significantly than that before treatment(all P<0.01).Conclusion:The release technique of long round-sharp needle achieves the satisfactory clinical effect on SCN entrapment syndrome.Hence,this therapeutic method deserves to be promoted.
