Four focusing models for generation of freak waves are presented. An extreme wave focusing model is presented on the basis of the enhanced High-Order Spectral （HOS） method and the importance of the nonlinear wave-wa...Four focusing models for generation of freak waves are presented. An extreme wave focusing model is presented on the basis of the enhanced High-Order Spectral （HOS） method and the importance of the nonlinear wave-wave interaction is evaluated by comparison of the calculated results with experimental and theoretical data. Based on the modification of the Longuet-Higgins model, four wave models for generation of freak waves （a. extreme wave model ＋ random wave model; b. extreme wave model ＋ regular wave model; e. phase interval modulation wave focusing model; d. number modulation wave focusing model with the same phase） are proposed. By use of different energy distribution techniques in the four models, freak wave events are obtained with different Hmax/Hs in finite space and time.展开更多
This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of fo...This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.展开更多
Objective: To explore the clinical intervention effect of focusing on solving nursing mode in the nursing of puerperal hemorrhage in primiparas, and the value in improving the quality of life of patients. Methods: a t...Objective: To explore the clinical intervention effect of focusing on solving nursing mode in the nursing of puerperal hemorrhage in primiparas, and the value in improving the quality of life of patients. Methods: a total of 110 primiparas admitted in our hospital from September 2019 to September 2020 were studied, all complicated with different degrees of postpartum hemorrhage. Patients were divided equally according to the randomness principle, 55 cases in the observation group received focused solution nursing mode intervention, while 55 cases in the control group only received postoperative basic care.Results: There were no significant differences in anxiety scores and depression scores between the two groups before nursing work (P>0.05). After carrying out nursing work, anxiety and depression scores of observation group were significantly different from those of control group (P<0.05). The scores of satisfaction and quality of life of pregnant women in the observation group were higher after nursing intervention (P<0.05). In the observation group, the scores of positive stress coping styles such as emotion, support, coping and optimism were higher than those in the control group, while the scores of negative stress coping styles such as conservatism, avoidance, resignation and self-dependence were lower than those in the control group, with significant differences (P<0.05). There was no difference in DT score between the two groups before nursing intervention (P>0.05). After intervention, the level in observation group was lower than that in control group (P<0.05). Conclusion: The intervention of focused solution nursing mode for patients with postpartum hemorrhage in primary labor has ideal effect, negative psychological status is improved, and the quality of life can be significantly improved, which can promote the improvement of stress coping ability of primiparas and improve psychological pain, and has application value.展开更多
Based on the Longuet-Higgins wave model theory, the previews studies have shown that freak waves can be generated in finite space and time successfully. However, as to generating high nonlinear freak waves, the simula...Based on the Longuet-Higgins wave model theory, the previews studies have shown that freak waves can be generated in finite space and time successfully. However, as to generating high nonlinear freak waves, the simulation results will be unrealistic. Therefore, a modified phase modulation method for simulating high nonlinear freak waves was developed. The surface elevations of some wave components at certain time and place are positive by modulating the corresponding random initial phases, then the total surface elevation at the focused point is enhanced and furthermore a freak wave event is generated. The new method can not only make the freak wave occur at certain time and place, but also make the simulated wave surface time series satisfy statistical properties of the realistic sea state and keep identical with the target wave spectrum. This numerical approach is of good precision and high efficiency by the comparisons of the simulated freak waves and the recorded freak waves.展开更多
In this paper, a numerical model is developed based on the High Order Spectral （HOS） method with a non-periodic boundary. A wave maker boundary condition is introduced to simulate wave generation at the incident bou...In this paper, a numerical model is developed based on the High Order Spectral （HOS） method with a non-periodic boundary. A wave maker boundary condition is introduced to simulate wave generation at the incident boundary in the HOS method. Based on the numerical model, the effects of wave parameters, such as the assumed focused amplitude, the central frequency, the frequency bandwidth, the wave amplitude distribution and the directional spreading on the surface elevation of the focused wave, the maximum generated wave crest, and the shifting of the focusing point, are numerically investigated. Especially, the effects of the wave directionality on the focused wave properties are emphasized. The numerical results show that the shifting of the focusing point and the maximum crest of the wave group are dependent on the amplitude of the focused wave, the central frequency, and the wave amplitude distribution type. The wave directionality has a definite effect on multidirectional focused waves. Generally, it can even out the difference between the simulated wave amplitude and the amplitude expected from theory and reduce the shifting of the focusing points, implying that the higher order interaction has an influence on wave focusing, especially for 2D wave. In 3D wave groups, a broader directional spreading weakens the higher nonlinear interactions.展开更多
In this paper, a numerical model for nonlinear wave propagation in currents is formulated by a set of enhanced fully nonlinear Boussinesq equations with ambient currents. This model is verified by comparison with the ...In this paper, a numerical model for nonlinear wave propagation in currents is formulated by a set of enhanced fully nonlinear Boussinesq equations with ambient currents. This model is verified by comparison with the published results. Then the influence of currents on nonlinear focusing waves is studied by use of the numerical model. It is found that the effect of currents on the surface elevations at the fecal location is negligible. Following currents can augment the maximum crest of focusing wave while decrease the focusing time, and vice versa for opposing currents. Furthermore, both opposing and following currents can shift the focal location forward relative to that in quiescent water.展开更多
The focusing and the stable transport of an intense elliptic sheet electron beam in a uniform magnetic field are investigated thoroughly by using the macroscopic cold-fluid model and the single-particle orbit theory.T...The focusing and the stable transport of an intense elliptic sheet electron beam in a uniform magnetic field are investigated thoroughly by using the macroscopic cold-fluid model and the single-particle orbit theory.The results indicate that the envelopes and the tilted angles of the sheet electron beam obtained by the two theories are consistent.The single-particle orbit theory is more accurate due to its treatment of the space-charge fields in a rectangular drift tube.The macroscopic cold-fluid model describes the collective transport process in order to provide detailed information about the beam dynamics,such as beam shape,density,and velocity profile.The tilt of the elliptic sheet beam in a uniform magnetic field is carefully studied and demonstrated.The results presented in this paper provide two complete theories for systemically discussing the transport of the sheet beam and are useful for understanding and guiding the practical engineering design of electron optics systems in high power vacuum electronic devices.展开更多
In this paper,a non-contact auto-focusing method is proposed for the essential function of auto-focusing in mobile devices.Firstly,we introduce an effective target detection method combining the 3-frame difference alg...In this paper,a non-contact auto-focusing method is proposed for the essential function of auto-focusing in mobile devices.Firstly,we introduce an effective target detection method combining the 3-frame difference algorithm and Gauss mixture model,which is robust for complex and changing background.Secondly,a stable tracking method is proposed using the local binary patter feature and camshift tracker.Auto-focusing is achieved by using the coordinate obtained during the detection and tracking procedure.Experiments show that the proposed method can deal with complex and changing background.When there exist multiple moving objects,the proposed method also has good detection and tracking performance.The proposed method implements high efficiency,which means it can be easily used in real mobile device systems.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50779004)
文摘Four focusing models for generation of freak waves are presented. An extreme wave focusing model is presented on the basis of the enhanced High-Order Spectral （HOS） method and the importance of the nonlinear wave-wave interaction is evaluated by comparison of the calculated results with experimental and theoretical data. Based on the modification of the Longuet-Higgins model, four wave models for generation of freak waves （a. extreme wave model ＋ random wave model; b. extreme wave model ＋ regular wave model; e. phase interval modulation wave focusing model; d. number modulation wave focusing model with the same phase） are proposed. By use of different energy distribution techniques in the four models, freak wave events are obtained with different Hmax/Hs in finite space and time.
基金Project supported by the Natural Science Foundation of Henan Province, China （Grant No 0611054000）.
文摘This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.
文摘Objective: To explore the clinical intervention effect of focusing on solving nursing mode in the nursing of puerperal hemorrhage in primiparas, and the value in improving the quality of life of patients. Methods: a total of 110 primiparas admitted in our hospital from September 2019 to September 2020 were studied, all complicated with different degrees of postpartum hemorrhage. Patients were divided equally according to the randomness principle, 55 cases in the observation group received focused solution nursing mode intervention, while 55 cases in the control group only received postoperative basic care.Results: There were no significant differences in anxiety scores and depression scores between the two groups before nursing work (P>0.05). After carrying out nursing work, anxiety and depression scores of observation group were significantly different from those of control group (P<0.05). The scores of satisfaction and quality of life of pregnant women in the observation group were higher after nursing intervention (P<0.05). In the observation group, the scores of positive stress coping styles such as emotion, support, coping and optimism were higher than those in the control group, while the scores of negative stress coping styles such as conservatism, avoidance, resignation and self-dependence were lower than those in the control group, with significant differences (P<0.05). There was no difference in DT score between the two groups before nursing intervention (P>0.05). After intervention, the level in observation group was lower than that in control group (P<0.05). Conclusion: The intervention of focused solution nursing mode for patients with postpartum hemorrhage in primary labor has ideal effect, negative psychological status is improved, and the quality of life can be significantly improved, which can promote the improvement of stress coping ability of primiparas and improve psychological pain, and has application value.
基金The Key Technology Program,the Ministry of Education of China under contract No.104061
文摘Based on the Longuet-Higgins wave model theory, the previews studies have shown that freak waves can be generated in finite space and time successfully. However, as to generating high nonlinear freak waves, the simulation results will be unrealistic. Therefore, a modified phase modulation method for simulating high nonlinear freak waves was developed. The surface elevations of some wave components at certain time and place are positive by modulating the corresponding random initial phases, then the total surface elevation at the focused point is enhanced and furthermore a freak wave event is generated. The new method can not only make the freak wave occur at certain time and place, but also make the simulated wave surface time series satisfy statistical properties of the realistic sea state and keep identical with the target wave spectrum. This numerical approach is of good precision and high efficiency by the comparisons of the simulated freak waves and the recorded freak waves.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51309050 and 51221961)the National Basic Research Program of China(973 Program,Grant Nos.2013CB036101 and 2011CB013703)
文摘In this paper, a numerical model is developed based on the High Order Spectral （HOS） method with a non-periodic boundary. A wave maker boundary condition is introduced to simulate wave generation at the incident boundary in the HOS method. Based on the numerical model, the effects of wave parameters, such as the assumed focused amplitude, the central frequency, the frequency bandwidth, the wave amplitude distribution and the directional spreading on the surface elevation of the focused wave, the maximum generated wave crest, and the shifting of the focusing point, are numerically investigated. Especially, the effects of the wave directionality on the focused wave properties are emphasized. The numerical results show that the shifting of the focusing point and the maximum crest of the wave group are dependent on the amplitude of the focused wave, the central frequency, and the wave amplitude distribution type. The wave directionality has a definite effect on multidirectional focused waves. Generally, it can even out the difference between the simulated wave amplitude and the amplitude expected from theory and reduce the shifting of the focusing points, implying that the higher order interaction has an influence on wave focusing, especially for 2D wave. In 3D wave groups, a broader directional spreading weakens the higher nonlinear interactions.
基金supported by the National Natural Science Foundation of China(Grant Nos.50679010 and 50921001)the Program for New Century Excellent Talents in Universities of China(Grant No.NCET-05-0282)
文摘In this paper, a numerical model for nonlinear wave propagation in currents is formulated by a set of enhanced fully nonlinear Boussinesq equations with ambient currents. This model is verified by comparison with the published results. Then the influence of currents on nonlinear focusing waves is studied by use of the numerical model. It is found that the effect of currents on the surface elevations at the fecal location is negligible. Following currents can augment the maximum crest of focusing wave while decrease the focusing time, and vice versa for opposing currents. Furthermore, both opposing and following currents can shift the focal location forward relative to that in quiescent water.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60501019,10775139 and 60971073)
文摘The focusing and the stable transport of an intense elliptic sheet electron beam in a uniform magnetic field are investigated thoroughly by using the macroscopic cold-fluid model and the single-particle orbit theory.The results indicate that the envelopes and the tilted angles of the sheet electron beam obtained by the two theories are consistent.The single-particle orbit theory is more accurate due to its treatment of the space-charge fields in a rectangular drift tube.The macroscopic cold-fluid model describes the collective transport process in order to provide detailed information about the beam dynamics,such as beam shape,density,and velocity profile.The tilt of the elliptic sheet beam in a uniform magnetic field is carefully studied and demonstrated.The results presented in this paper provide two complete theories for systemically discussing the transport of the sheet beam and are useful for understanding and guiding the practical engineering design of electron optics systems in high power vacuum electronic devices.
基金supported by ZTE Industry-Academia-Research Cooperation Funds
文摘In this paper,a non-contact auto-focusing method is proposed for the essential function of auto-focusing in mobile devices.Firstly,we introduce an effective target detection method combining the 3-frame difference algorithm and Gauss mixture model,which is robust for complex and changing background.Secondly,a stable tracking method is proposed using the local binary patter feature and camshift tracker.Auto-focusing is achieved by using the coordinate obtained during the detection and tracking procedure.Experiments show that the proposed method can deal with complex and changing background.When there exist multiple moving objects,the proposed method also has good detection and tracking performance.The proposed method implements high efficiency,which means it can be easily used in real mobile device systems.
