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Nonlinear Violence in Nonlinear Oscillations at High Energy
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作者 Yair Zarmi 《Applied Mathematics》 2024年第1期65-95,共31页
This paper focuses on the characteristics of solutions of nonlinear oscillatory systems in the limit of very high oscillation energy, E;specifically, systems, in which the nonlinear driving force grows with energy muc... This paper focuses on the characteristics of solutions of nonlinear oscillatory systems in the limit of very high oscillation energy, E;specifically, systems, in which the nonlinear driving force grows with energy much faster for x(t) close to the turning point, a(E), than at any position, x(t), that is not too close to a(E). This behavior dominates important aspects of the solutions. It will be called “nonlinear violence”. In the vicinity of a turning point, the solution of a nonlinear oscillatory systems that is affected by nonlinear violence exhibits the characteristics of boundary-layer behavior (independently of whether the equation of motion of the system can or cannot be cast in the traditional form of a boundary-layer problem.): close to a(E), x(t) varies very rapidly over a short time interval (which vanishes for E → ∞). In traditional boundary layer systems this would be called the “inner” solution. Outside this interval, x(t) soon evolves into a moderate profile (e.g. linear in time, or constant)—the “outer” solution. In (1 + 1)-dimensional nonlinear energy-conserving oscillators, if the solution is reflection-invariant, nonlinear violence determines the characteristics of the whole solution. For large families of nonlinear oscillatory systems, as E → ∞, the solutions for x(t) tend to common, indistinguishable profiles, such as periodic saw-tooth profiles or step-functions. If such profiles are observed experimentally in high-energy oscillations, it may be difficult to decipher the dynamical equations that govern the motion. The solution of motion in a central field with a non-zero angular momentum exhibits extremely fast rotation around a turning point that is affected by nonlinear violence. This provides an example for the possibility of interesting phenomena in (1 + 2)-dimensional oscillatory systems. 展开更多
关键词 high-Energy oscillations Nonlinear Violence Boundary-Layer Characteristics
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Identification and Analysis of High-Frequency Oscillations in the Eyewalls of Tropical Cyclones 被引量:2
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作者 CHEN Shumin Youyu LU +1 位作者 LI Weibiao WEN Zhiping 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第5期624-634,共11页
High-frequency oscillations, with periods of about 2 hours, are first identified by applying wavelet analysis to observed minutely wind speeds around the eye and eyewall of tropical cyclones(TCs). Analysis of a mode... High-frequency oscillations, with periods of about 2 hours, are first identified by applying wavelet analysis to observed minutely wind speeds around the eye and eyewall of tropical cyclones(TCs). Analysis of a model simulation of Typhoon Hagupit(2008) shows that the oscillations also occur in the TC intensity, vertical motion, convergence activity and air density around the eyewall. Sequences of oscillations in these variables follow a certain order. 展开更多
关键词 tropical cyclone high-frequency oscillations EYEWALL INTENSITY
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Variations in High-frequency Oscillations of Tropical Cyclones over the Western North Pacific 被引量:1
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作者 Shumin CHEN Weibiao LI +5 位作者 Zhiping WEN Mingsen ZHOU Youyu LU Yu-Kun QIAN Haoya LIU Rong FANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第4期423-434,共12页
Variations in the high-frequency oscillations of tropical cyclones (TCs) over the western North Pacific (WNP) are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m (MW... Variations in the high-frequency oscillations of tropical cyclones (TCs) over the western North Pacific (WNP) are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m (MWS10) from an ensemble of 15 simulated TCs shows that oscillations are significant for all TCs. The magnitudes of oscillations in MWS10 are similar in the WNP and South China Sea (SCS); however, the mean of the averaged significant periods in the SCS (1.93 h) is shorter than that in the open water of the WNP (2.83 h). The shorter period in the SCS is examined through an ensemble of simulations, and a case simulation as well as a sensitivity experiment in which the continent is replaced by ocean for Typhoon Hagupit (2008). The analysis of the convergence efficiency within the boundary layer suggests that the shorter periods in the SCS are possibly due to the stronger terrain effect, which intensifies convergence through greater friction. The enhanced convergence strengthens the disturbance of the gradient and thermal wind balances, and then contributes to the shorter oscillation periods in the SCS. 展开更多
关键词 tropical cyclone high-frequency oscillation western North Pacific South China Sea
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Characteristics of low-frequency oscillations in course of SCS summer monsoon onset
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作者 毛江玉 谢安 +1 位作者 宋焱云 叶谦 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2000年第3期65-72,共8页
Some of the low-frequency oscillation (LFO) characteristics of summer moan onset over the South China Sea (SCS) are examined based on NCEP/NCAR reanalysis data and OLR from NOAA in the period of 1979-1996. It is found... Some of the low-frequency oscillation (LFO) characteristics of summer moan onset over the South China Sea (SCS) are examined based on NCEP/NCAR reanalysis data and OLR from NOAA in the period of 1979-1996. It is found that the SCS summer monsoon is characterized by predominance of low-frequency activities with significant interannual variability closely related with onset time. The LFOs over the SCS strengthen after onset. Composite analyses for LFO components of OLR and kinetic energy indicate that the eastward propagation of LFO over the equatorial Indian Ocean and LFO coming from the western Pacific strongly affect the physical processes responsible for the SCS summer monsoon onset. The SCS is the place where the Indian Ocean LFO links with low-frequency activities over the western pacific during summer monsoon onset. 展开更多
关键词 Low -frequency oscillation the South China Sea summer moan onset
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A note for the mechanism of high-frequency oscillation instability resulted from absorbing boundary conditions
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作者 谢志南 廖振鹏 《Acta Seismologica Sinica(English Edition)》 CSCD 2008年第3期306-310,333,共6页
In this paper the explanation of the mechanism of high-frequency oscillation instability resulted from absorbing boundary conditions is further improved. And we analytically prove the proposition that for one dimensio... In this paper the explanation of the mechanism of high-frequency oscillation instability resulted from absorbing boundary conditions is further improved. And we analytically prove the proposition that for one dimensional discrete model of elastic wave motion, the module of reflection factor will be greater than 1 in high frequency band when artificial wave velocity is greater than 1.5 times the ratio of discrete space step to discrete time step. Based on the proof, the frequency band in which instability occurs is discussed in detail, showing such high-frequency waves are meaningless for the numerical simulation of wave motion. 展开更多
关键词 absorbing boundary conditions high-frequency oscillation instability wave equation numerical simulation
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Comparison of High-Frequency Oscillation Ventilation with Conventional Mandatory Ventilation in Animal ARDS Model
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作者 SHI Guo-chao HUANG Shao-guang LI Min DENG Wei-wa WAN Huan-ying 《上海第二医科大学学报》 CSCD 北大核心 2005年第10期1091-1091,共1页
关键词 振动频率 通风技术 动物实验 爱滋病
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Improvement of circuit oscillation generated by underwater high voltage pulse discharges based on pulse power thyristor
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作者 于营波 康忠健 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第3期150-160,共11页
High voltage fracturing technology was widely used in the field of reservoir reconstruction due to its advantages of being clean, pollution-free, and high-efficiency. However, high-frequency circuit oscillation occurs... High voltage fracturing technology was widely used in the field of reservoir reconstruction due to its advantages of being clean, pollution-free, and high-efficiency. However, high-frequency circuit oscillation occurs during the underwater high voltage pulse discharge process, which brings security risks to the stability of the pulse fracturing system. In order to solve this problem, an underwater pulse power discharge system was established, the circuit oscillation generation conditions were analyzed and the circuit oscillation suppression method was proposed. Firstly, the system structure was introduced and the charging model of the energy storage capacitor was established by the state space average method. Next, the electrode high-voltage breakdown model was established through COMSOL software, the electrode breakdown process was analyzed according to the electron density distribution image, and the plasma channel impedance was estimated based on the conductivity simulation results. Then the underwater pulse power discharge process and the circuit oscillation generation condition were analyzed, and the circuit oscillation suppression strategy of using the thyristor to replace the gas spark switch was proposed. Finally, laboratory experiments were carried out to verify the precision of the theoretical model and the suppression effect of circuit oscillation. The experimental results show that the voltage variation of the energy storage capacitor, the impedance change of the pulse power discharge process, and the equivalent circuit in each discharge stage were consistent with the theoretical model. The proposed oscillation suppression strategy cannot only prevent the damage caused by circuit oscillation but also reduce the damping oscillation time by77.1%, which can greatly improve the stability of the system. This research has potential application value in the field of underwater pulse power discharge for reservoir reconstruction. 展开更多
关键词 underwater high voltage pulse discharge circuit oscillation suppression state space average method pulse power thyristor
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Possible Impacts of Winter Arctic Oscillation on Siberian High, the East Asian Winter Monsoon and Sea-Ice Extent 被引量:41
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作者 武炳义 王佳 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2002年第2期297-320,共24页
Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953 to 1995, we... Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953 to 1995, we investigate connections between winter Arctic Oscillation (AO) and Siberian high (SH), the East Asian winter monsoon (EAWM), and winter sea-ice extent in the Barents Sea. The results indicate that winter AO not only influences climate variations in the Arctic and the North Atlantic sector, but also shows possible effects on winter SH, and further influences EAWM, When winter AO is in its positive phase, both of winter SH and the EAWM are weaker than normal, and air temperature from near the surface to the middle troposphere is about 0.5-2degreesC higher than normal in the southeastern Siberia and the East Asian coast, including eastern China, Korea, and Japan. When AO reaches its negative phase, an opposite scenario can be observed. The results also indicate that winter SH has no significant effects on climate variations in Arctic and the North Atlantic sector. Its influence intensity and extent are obviously weaker than AO, exhibiting a 'local, feature in contrast to AO. This study further reveals the possible mechanism of how the winter AO is related to winter SH. It is found that winter SH variation is closely related to both dynamic processes and air temperature variations from the surface to the middle troposphere. The western SH variation mainly depends on dynamic processes, while its eastern part is more closely related to air temperature variation. The maintaining of winter SH mainly depends on downward motion of airflow of the nearly entire troposphere. The airflow originates from the North Atlantic sector, whose variation is influenced by the AO. When AO is in its positive (negative) phase, downward motion remarkably weakened (strengthened), which further influences winter SH. In addition, winter AO exhibits significant influences on the simultaneous sea-ice extent in the Barents Sea. 展开更多
关键词 Arctic oscillation (AO) Siberian high East asian winter monsoon sea-ice extent
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An Observational Study of the 30-50 Day Atmospheric Oscillations Part I: Structure and Propagation 被引量:20
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作者 李崇银 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1990年第3期294-304,共11页
Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the ... Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the equatorial region. Those in the mid-high latitudes, however, are revealed to be very different from the tropics and pose a strong barotropic structure. Horizontal coherence shows teleconnection patterns which can be identified as EAP and PNA. The wind field of the specified time scale of the oscillation appears as long-lived vortices and vortex pairs. Mid-latitude perturbations propagate clearly westwards, especially during the winter season. In the high latitudes, they propagate westwards in the winter but eastwards in the summer. Meridional propagations are rather different from region to region. 展开更多
关键词 An Observational Study of the 30-50 Day Atmospheric oscillations Part I high
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A 37 mJ,100 Hz,high energy single frequency oscillator 被引量:1
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作者 Yu Shen Yong Bo +3 位作者 Nan Zong Shenjin Zhang Qinjun Peng Zuyan Xu 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第8期392-397,共6页
Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single... Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single-frequency Nd:YAG oscillator is obtained.The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported.The result proves that this method does help for energy enhancement.It has attractive potential for high energy single frequency oscillator design,especially on condition of intensive side pumped or long cavity laser,where strong competitors exist and are hard to be suppressed. 展开更多
关键词 Nd:YAG laser high pulse energy single frequency oscillator
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Oscillation of Higher Order Linear Impulsive Dynamic Equations on Time Scales
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作者 Chaolong Zhang Feiqi Deng 《Applied Mathematics》 2012年第6期581-586,共6页
In this paper, we will establish some oscillation criteria for the higher order linear dynamic equation on time scale in term of the coefficients and the graininess function. We illustrate our results with an example.
关键词 oscilLATION high Order Dynamic EQUATION Time SCALE RICCATI Tramsformation
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Shock oscillation in highly underexpanded jets
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作者 Xiao-Peng Li Rui Zhou +2 位作者 Xiao-Ping Chen Xue-Jun Fan Guo-Shan Xie 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第9期396-409,共14页
The oscillatory motions of shocks in highly underexpanded jets with nozzle pressure ratios of 5.60, 7.47, 9.34, and11.21 are quantitatively studied by using large eddy simulation. Two types of shock oscillations are o... The oscillatory motions of shocks in highly underexpanded jets with nozzle pressure ratios of 5.60, 7.47, 9.34, and11.21 are quantitatively studied by using large eddy simulation. Two types of shock oscillations are observed: one is the Mach disk oscillation in the streamwise direction and the other is the shock oscillation in the radial direction. It is found that the Mach disk moves quickly in the middle of the oscillatory region but slowly at the top or bottom boundaries. The oscillation cycles of Mach disk are the same for different cases, and are all dominated by an axisymmetric mode of 5.298 k Hz. For the oscillation in the radial direction, the shocks oscillate more toward the jet centerline but less in the jet shear layer, and the oscillation magnitude is an increasing function of screech amplitude. The cycles of the radial shock oscillation switch randomly between the two screech frequencies for the first two cases. However, the oscillation periodicity is more complex for the jets with high nozzle pressure ratios of 9.34 and 11.21 than for the jets with the low nozzle pressure ratios of 5.6 and 7.47. In addition, the shock oscillation characteristics are also captured by coarse mesh and Smagorinsky model,but the coarse mesh tends to predict a slower and weaker shock oscillation. 展开更多
关键词 highly underexpanded jets shock oscillation large eddy simulation
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Generation-channel interference of high-order harmonics of an anharmonic oscillator driven by bi-chrime laser fields and its mechanism
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作者 王黎明 蔡俊 乔豪学 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第7期142-150,共9页
A method to describe the generation channels of high-order harmonics is proposed. According to this method, the mechanism of generation-channel interference of high-order harmonics is revealed clearly. We take the anh... A method to describe the generation channels of high-order harmonics is proposed. According to this method, the mechanism of generation-channel interference of high-order harmonics is revealed clearly. We take the anharmonic oscillator driven by bi-chrome fields as an example to illustrate that this method can be used to understand the effect of generation-channel interference. 展开更多
关键词 generation-channel interference anharmonic oscillator high-order harmonics
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Simulation of wind-induced near-inertial oscillations in a mixed layer near the east coast of Korea in the East/Japan Sea
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作者 NAM SungHyun PARK Young-Gyu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第9期11-20,共10页
Using a simple damped slab model, it was possible to show that a local wind induced 88% (15 of 17) of the near-inertial oscillations (NIO) observed in the mixed layer near the east coast of Korea from 1999 to 2004... Using a simple damped slab model, it was possible to show that a local wind induced 88% (15 of 17) of the near-inertial oscillations (NIO) observed in the mixed layer near the east coast of Korea from 1999 to 2004. The model, however, overestimated the energy level in about two-thirds of the simulated cases, because the slab model was forced with winds whose characteristic period was shorter than the damping time scale of the model at 1.5 d. At the observation site, due to typhoons and orographic effects, high-frequency wind forcing is quite common, as is the overestimation of the energy level in the slab model results. In short, a simple slab model with a damping time-scale of about 1.5 d would be enough to show that the local wind was the main energy source of the near-inertial energy in this area, but the model could not be used to accurately estimate the amount of the work done by the wind to the mixed layer. 展开更多
关键词 near-inertial oscillations near-inertial waves slab model high-frequency wind forcing eastcoast of Korea
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Simulational Investigation of a High-Efficiency X-Band Magnetically Insulated Line Oscillator
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作者 王晓玉 樊玉伟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第10期893-896,共4页
Abstract The magnetically insulated line oscillator (MILO) is a gigawatt-class, coaxial crossed-field microwave tube, which is at present a major hotspot in the field of high-power mi- crowaves (HPM) research. In ... Abstract The magnetically insulated line oscillator (MILO) is a gigawatt-class, coaxial crossed-field microwave tube, which is at present a major hotspot in the field of high-power mi- crowaves (HPM) research. In order to improve the power conversion efficiency and eliminate or at least minimize anode plasma formation in the load region and radio frequency (RF) breakdown in the slow wave structure (SWS) section, an X-band MILO is presented and inyestigated nu- merically with KARAT code. The design idea is briefly presented and the simulation results are given and discussed. In the simulation, HPM is generated with peak power of 3.4 GW, maximum electric field of about 1 MV/cm, and peak power conversion efficiency of 14.0%, when the voltage is 559.1 kV and the current is 43.2 kA. The microwave frequency is pure and falls in the X-band of 9.0 GHz. The theoretical investigation and the simulation results are given to prove that the anode plasma formation and the RF breakdown can be effectively avoided or at least minimized, respectively. 展开更多
关键词 high-power microwaves (HPM) magnetically insulated line oscillator (MILO) anode plasma radio frequency (RF) breakdown
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LC型VCO高温特性分析 被引量:1
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作者 刘长江 刘银生 高晓强 《电子工艺技术》 2024年第1期10-13,共4页
微波单片集成电路(MMIC)具有噪声性能好、集成度高、驱动能力强的优点。在MMIC工艺下,对压控振荡器(VCO)在高温下的特性表现进行了分析。现有使用负阻振荡原理设计的VCO电路分为负阻电路部分和谐振电路部分,该结构在高温下常产生近端噪... 微波单片集成电路(MMIC)具有噪声性能好、集成度高、驱动能力强的优点。在MMIC工艺下,对压控振荡器(VCO)在高温下的特性表现进行了分析。现有使用负阻振荡原理设计的VCO电路分为负阻电路部分和谐振电路部分,该结构在高温下常产生近端噪声恶化和频率下降的现象,影响VCO的正常工作性能。通过对现有MMICVCO产品的仿真测试和分析,探得了高温下VCO性能改变的原因。 展开更多
关键词 MMIC 压控振荡器 高温特性改变
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一种基于嵌套结构的锁频锁相高功率微波振荡器仿真研究
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作者 李家文 葛行军 +4 位作者 党方超 张鹏 邓如金 胡晓冬 李志敏 《强激光与粒子束》 CAS CSCD 北大核心 2024年第3期24-30,共7页
高功率微波(HPM)产生器件通过增加慢波结构的过模比使得功率容量显著提高。嵌套型结构让过模器件的空心结构或内导体结构得到使用,同时嵌套型器件的低阻抗使得其与低阻脉冲功率源能良好匹配。基于内外嵌套结构提出了一种锁频锁相高功率... 高功率微波(HPM)产生器件通过增加慢波结构的过模比使得功率容量显著提高。嵌套型结构让过模器件的空心结构或内导体结构得到使用,同时嵌套型器件的低阻抗使得其与低阻脉冲功率源能良好匹配。基于内外嵌套结构提出了一种锁频锁相高功率微波振荡器。相对于传统的锁频锁相方法,提出了基于耦合波导实现锁频锁相的新方法。内外相对论速调管振荡器(RKO)产生的微波信号通过耦合波导泄漏到高频结构中,对电子束进行预调制,从而实现锁频锁相。另外,为实现内外高功率微波通道合成,设计了双通道功率合成器。在振荡器的工作频点,功率合成器能弥补振荡器两输出通道相位差,使得功率合成效率提高,合成效率为98.3%。在二极管电压575 kV,磁场强度0.6 T条件下,内外RKO的微波输出功率分别为2.2 GW和3.2 GW,频率差波动小于20 MHz,相位差稳定在10°附近;加载双通道功率合成器,仿真结果表明,微波输出功率为5.31 GW,功率效率32.2%。结果表明,嵌套器件在互锁状态时,振荡器饱和时间缩短,输出功率增大。 展开更多
关键词 高功率微波 锁频锁相 嵌套结构 相对论速调管振荡器 功率合成
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一种抑制栅极正负向串扰的GaN HEMT无源驱动电路
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作者 王忠 秦世清 +1 位作者 王福学 边国辉 《半导体技术》 CAS 北大核心 2024年第5期483-491,共9页
GaN器件由于其更快的开关速度,比硅器件更容易发生严重的开关振荡,也更容易受到栅源电压振荡的影响。为了抑制GaN基半桥结构中的串扰,提出了一种抑制GaN高电子迁移率晶体管(HEMT)栅极正负向串扰的无源钳位驱动电路来抑制栅源电压振荡。... GaN器件由于其更快的开关速度,比硅器件更容易发生严重的开关振荡,也更容易受到栅源电压振荡的影响。为了抑制GaN基半桥结构中的串扰,提出了一种抑制GaN高电子迁移率晶体管(HEMT)栅极正负向串扰的无源钳位驱动电路来抑制栅源电压振荡。采用基本无源元件建立自举驱动回路,并增加三极管以构成从驱动电路到GaN HEMT的低阻抗米勒电流路径,抑制正负向串扰。在LTspice软件下进行电路模拟仿真,并搭建实验平台进行实测验证,结果表明栅源电压的最大正向串扰可降至1.2 V,最大负向串扰可降至1.6 V,漏源电流的正向和负向串扰均降至2 A以下,证明该电路对栅源电压以及漏源电流的振荡均有良好的抑制效果。 展开更多
关键词 GaN高电子迁移率晶体管(HEMT) 驱动电路 串扰 桥式电路 电路振荡
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支气管镜肺泡灌洗联合高频振荡排痰在大叶性肺炎治疗中的应用价值探讨
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作者 王桂英 田立华 《中国现代药物应用》 2024年第13期40-43,共4页
目的探讨支气管镜肺泡灌洗联合高频振荡排痰机在大叶性肺炎患儿中的临床治疗效果及应用价值。方法60例大叶性肺炎患儿为研究对象,采用简单化随机法将患儿分为对照组(30例)和观察组(30例)。对照组患儿实施常规对症治疗联合高频振荡排痰机... 目的探讨支气管镜肺泡灌洗联合高频振荡排痰机在大叶性肺炎患儿中的临床治疗效果及应用价值。方法60例大叶性肺炎患儿为研究对象,采用简单化随机法将患儿分为对照组(30例)和观察组(30例)。对照组患儿实施常规对症治疗联合高频振荡排痰机,观察组在对照组基础上增加支气管镜肺泡灌洗进行治疗。比较两组患儿的临床疗效、肺功能指标(最大呼气中段平均流速、第1秒用力呼气容积和用力肺活量)、血清炎症指标[降钙素原(PCT)、C反应蛋白(CRP)]和不良事件发生率。结果与对照组(80.0%)比较,观察组临床总有效率(96.7%)明显升高(P<0.05)。与治疗前比较,治疗后两组最大呼气中段平均流速、第1秒用力呼气容积和用力肺活量均有所升高(P<0.05);治疗后观察组患儿的最大呼气中段平均流速(1.92±0.38)L/s、第1秒用力呼气容积(1.85±0.33)L、用力肺活量(3.54±0.67)L高于对照组的(1.32±0.31)L/s、(1.27±0.29)L、(2.15±0.48)L(P<0.05)。与治疗前比较,治疗后两组血清CRP和PCT水平均有所降低(P<0.05);治疗后观察组患儿血清CRP(2.27±0.19)mg/L、PCT(0.08±0.02)ng/ml明显低于对照组的(6.68±0.85)mg/L、(0.16±0.05)ng/ml(P<0.05)。两组患儿不良事件发生率比较无统计学差异(P>0.05)。结论支气管镜肺泡灌洗联合高频振荡排痰机在大叶性肺炎患儿中的临床疗效显著,能有效改善患儿的肺功能,降低患儿血清中炎症因子水平,且安全性良好,值得临床推广应用。 展开更多
关键词 大叶性肺炎 支气管镜肺泡灌洗 高频振荡排痰机 肺功能
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双极化复用信号的接收技术研究
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作者 唐婷 《电子设计工程》 2024年第6期146-150,共5页
针对双极化复用传输系统的交叉极化干扰问题,提出一种适用于双极化复用信号的接收技术。在接收链路本振不同源的情况下,参考信号与干扰信号载波频率不同,干扰不能被对消。从理论上推导了参考信号与干扰信号之间的频率关系,并通过频率补... 针对双极化复用传输系统的交叉极化干扰问题,提出一种适用于双极化复用信号的接收技术。在接收链路本振不同源的情况下,参考信号与干扰信号载波频率不同,干扰不能被对消。从理论上推导了参考信号与干扰信号之间的频率关系,并通过频率补偿模块消除参考信号与干扰信号间的频差,使得参考信号与干扰信号频率一致,从而实现极化干扰对消。测试结果表明,链路本振不同源的情况下,该方法可有效减少交叉极化干扰带来的误码率恶化。 展开更多
关键词 交叉极化干扰 不同频率源 频率补偿 高速解调
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