The characteristics of magnetohydrodynamic fast wave propagation in the solar stratified atmosphere are studied by the ray tracing method. The propagation behaviour of the wavefronts is described in detail. A magnetic...The characteristics of magnetohydrodynamic fast wave propagation in the solar stratified atmosphere are studied by the ray tracing method. The propagation behaviour of the wavefronts is described in detail. A magnetic field incorporating the characteristics field spreading expected in flux tubes is used, which represents the main feature of an active region. Partly ionization is considered beside the stratified solar atmosphere consisting chromosphere, transition region and corona. The study may explain the characteristics in observations of Moreton and extraultraviolet image telescope （EIT） waves. The wavefront incurred by the disturbance initialized at the base of the transition region propagates fast initially due to strong magnetic field, and it slows down when arriving beyond the region of flux-tube. Meanwhile, the wave propagates in the corona with a more consistent speed, as seen in the observation of EIT waves. The speeds and propagated characteristics in chromosphere and corona of the wavefronts are in agreement with those observed in H~ Moreton and EIT waves, respectively.展开更多
The South China Sea （SCS）, in particular the northern SCS, is one of ocean areas where energetic internal solitary waves （ISWs）occur most frequently （Cai et al., 2012; Zheng, 2017）. Based on the re-appearance pe...The South China Sea （SCS）, in particular the northern SCS, is one of ocean areas where energetic internal solitary waves （ISWs）occur most frequently （Cai et al., 2012; Zheng, 2017）. Based on the re-appearance period （RP） at an observation station, Ramp et al.（2004） divided the ISWs into two types：Type-a and Type-b. Type-a ISWs arrive regularly at the same time every day, i.e., the RP is about 24 h, and Type-b ISWs arrive about one hour late every day, i.e., the RP is about 25 h.展开更多
Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling i...Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling is very important because it is the theoretical foundation for further study in the WUSV motion control and efficiency analysis.In this work,the multibody system of WUSV was described based on D-H approach.Then,the driving principle was analyzed and the dynamic model of WUSV in longitudinal profile is established by Lagrangian mechanics.Finally,the motion simulation of WUSV and comparative analysis are completed by setting different inputs of sea state.Simulation results show that the WUSV dynamic model can correctly reflect the WUSV longitudinal motion process,and the results are consistent with the wave theory.展开更多
Lower hybrid heating (LHH) has been successfully carried out in the HT-6M toka-mak. The H-mode has been obtained with a power threshold of 50 kW under a boronized wall condition. Both energy and particle confinements ...Lower hybrid heating (LHH) has been successfully carried out in the HT-6M toka-mak. The H-mode has been obtained with a power threshold of 50 kW under a boronized wall condition. Both energy and particle confinements have been improved along with a dropped edge plasma density and an increase electron temperature during the LHH phase. A negative Er well plays a key role of triggering and sustaining the good confinement. Both electrostatic fluctuation of the plasma potential and the density fluctuations dropped to an ultra-low level. The observation of an enhanced Er shear before the reduction in turbulence level is consistent with an increased Er shear as the cause of turbulence suppression.展开更多
Objective: Health care providers refer their patients to electromyography (E<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdan...Objective: Health care providers refer their patients to electromyography (E<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">MG) laboratories for the evaluation of various sensory symptoms in the extremities and spine. The procedure is usually performed in conjunction with transcutaneous electrical stimulation of peripheral nerves and elicitation of the F-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">wave and H-reflex. The present study aimed to determine the real value of these procedures in the diagnosis of sensory symptoms in the setting of a normal neurologic examination. Method: The EMG reports and clinical histories of 100 patients, including 10 patients evaluated by other electromyographers, were reviewed. The study was focused on those with normal neurological examinations and those without histories of ongoing medical disorders and major surgeries to the extremities and spine.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">Results: All EMGs, F-wave, and H-reflex reports reviewed were normal, including those obtained </span><span style="font-family:Verdana;">from the second procedure performed in some patients and of those who su</span><span style="font-family:Verdana;">bsequently underwent spinal surgery. Neurologic examination in all patients</span><span style="font-family:Verdana;"> was </span><span style="font-family:Verdana;">normal. Conclusion: Needle EMG, F-wave and H-Reflex examinations are pr</span><span style="font-family:Verdana;">edictably normal in patients with non-dermatomal, non-neuropathic sensory symptoms with normal neurologic examination and without history of pre</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">existing medical and surgical disorders. A good neurologic examination sh</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ould determine the need to perform these procedures. Our findings have important diagnostic, therapeutic, prognostic, economic and legal implications</span></span></span><span style="font-family:Verdana;">.</span>展开更多
目的:探究24 h动态心电图(DCG)中房性快速心律失常与心电图P波时限及离散度的相关性。方法:选取2021年1月—2024年5月在厦门大学附属第一医院同时行常规心电图、24 h DCG检查的320例患者作为研究对象,将24 h DCG检查中出现房性心律失常...目的:探究24 h动态心电图(DCG)中房性快速心律失常与心电图P波时限及离散度的相关性。方法:选取2021年1月—2024年5月在厦门大学附属第一医院同时行常规心电图、24 h DCG检查的320例患者作为研究对象,将24 h DCG检查中出现房性心律失常的216例作为异常组,根据房性快速心律失常表现,将患者分为偶发房性早搏组、频发房性早搏组、短阵房速组、阵发性房颤组、阵发性房扑组,纳入两项检查均正常的104例患者作为正常组。比较正常组、异常组的心电图检测指标[P波最大时限(Pmax)、P波离散度(Pd)];采用多因素logistic回归分析24 h DCG中房性快速心律失常发生的影响因素;采用Spearman相关性分析模型,探讨Pmax、Pd与24 h DCG中房性快速心律失常发生的相关性。结果:异常组中偶发房性早搏组、频发房性早搏组、短阵房速组、阵发性房颤组、阵发性房扑组患者Pmax、Pd水平均高于正常组,差异有统计学意义(P<0.05);且短阵房速组、阵发性房颤组、阵发性房扑组患者Pmax、Pd水平均高于偶发房性早搏组,差异有统计学意义(P<0.05);多因素logistic回归分析结果显示,Pmax、Pd均为房性快速心律失常发生的危险因素(P<0.05);Spearman相关分析结果显示,Pmax、Pd水平与房性快速心律失常发生呈正相关(P<0.001)。结论:房性快速心律失常患者心电图常表现为Pmax、Pd水平升高,且Pmax、Pd异常水平与房性快速心律失常情况的发生具有显著相关性,临床可通过关注高危患者上述指标状况早期预警房性心律失常的发生。展开更多
Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synt...Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synthesized process is simple, low-cost and possible for application on transparent electrodes, gas sensors and thin film resistors. Analytical methods such as Raman spectroscopy, transmission electron microscopy (TEM) and four points prove resistivity measurement and UV-VIS-NIR spectroscopy were employed to characterize properties of the graphene films. The formation of multilayer of graphene on silicon substrate was confirmed by Raman spectroscopy and TEM. It is possible to grow graphene directly on silicon substrate (without using catalyst) due to high radical density of MW SWP CVD. In addition, we also observed that the hydrogen had significant role for quality of graphene.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 40274050 and 40336052, and the National Key Basic Research Special Foundation of China under Grant No G2000078405.
文摘The characteristics of magnetohydrodynamic fast wave propagation in the solar stratified atmosphere are studied by the ray tracing method. The propagation behaviour of the wavefronts is described in detail. A magnetic field incorporating the characteristics field spreading expected in flux tubes is used, which represents the main feature of an active region. Partly ionization is considered beside the stratified solar atmosphere consisting chromosphere, transition region and corona. The study may explain the characteristics in observations of Moreton and extraultraviolet image telescope （EIT） waves. The wavefront incurred by the disturbance initialized at the base of the transition region propagates fast initially due to strong magnetic field, and it slows down when arriving beyond the region of flux-tube. Meanwhile, the wave propagates in the corona with a more consistent speed, as seen in the observation of EIT waves. The speeds and propagated characteristics in chromosphere and corona of the wavefronts are in agreement with those observed in H~ Moreton and EIT waves, respectively.
基金The National Science and Technology Major Project of China under contract No.2016ZX05057015the National Natural Science Foundation of China under contract Nos 41376038 and 40406009+3 种基金the NSFC-Shandong Joint Fund for Marine Science Research Centers of China under contract No.U1606405the National Program on Global Change and Air-Sea Interaction of China under contract Nos GASI-03-01-01-02,GASI-02-IND-STSsum and GASI-IPOVAI-01-05the Public Science and Technology Research Funds Projects of Ocean of China under contract No.200905024the National Key Scientific Instrument and Equipment Development Projects of China under contract No.2012YQ12003908
文摘The South China Sea （SCS）, in particular the northern SCS, is one of ocean areas where energetic internal solitary waves （ISWs）occur most frequently （Cai et al., 2012; Zheng, 2017）. Based on the re-appearance period （RP） at an observation station, Ramp et al.（2004） divided the ISWs into two types：Type-a and Type-b. Type-a ISWs arrive regularly at the same time every day, i.e., the RP is about 24 h, and Type-b ISWs arrive about one hour late every day, i.e., the RP is about 25 h.
基金Project(2012-Z05)supported by the State Key Laboratory of Robotics,ChinaProjects(61233013,51179183)supported by the National Natural Science Foundation of China
文摘Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling is very important because it is the theoretical foundation for further study in the WUSV motion control and efficiency analysis.In this work,the multibody system of WUSV was described based on D-H approach.Then,the driving principle was analyzed and the dynamic model of WUSV in longitudinal profile is established by Lagrangian mechanics.Finally,the motion simulation of WUSV and comparative analysis are completed by setting different inputs of sea state.Simulation results show that the WUSV dynamic model can correctly reflect the WUSV longitudinal motion process,and the results are consistent with the wave theory.
基金This work was supported by National Science Foundation Project of China No.19975063.
文摘Lower hybrid heating (LHH) has been successfully carried out in the HT-6M toka-mak. The H-mode has been obtained with a power threshold of 50 kW under a boronized wall condition. Both energy and particle confinements have been improved along with a dropped edge plasma density and an increase electron temperature during the LHH phase. A negative Er well plays a key role of triggering and sustaining the good confinement. Both electrostatic fluctuation of the plasma potential and the density fluctuations dropped to an ultra-low level. The observation of an enhanced Er shear before the reduction in turbulence level is consistent with an increased Er shear as the cause of turbulence suppression.
文摘Objective: Health care providers refer their patients to electromyography (E<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">MG) laboratories for the evaluation of various sensory symptoms in the extremities and spine. The procedure is usually performed in conjunction with transcutaneous electrical stimulation of peripheral nerves and elicitation of the F-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">wave and H-reflex. The present study aimed to determine the real value of these procedures in the diagnosis of sensory symptoms in the setting of a normal neurologic examination. Method: The EMG reports and clinical histories of 100 patients, including 10 patients evaluated by other electromyographers, were reviewed. The study was focused on those with normal neurological examinations and those without histories of ongoing medical disorders and major surgeries to the extremities and spine.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">Results: All EMGs, F-wave, and H-reflex reports reviewed were normal, including those obtained </span><span style="font-family:Verdana;">from the second procedure performed in some patients and of those who su</span><span style="font-family:Verdana;">bsequently underwent spinal surgery. Neurologic examination in all patients</span><span style="font-family:Verdana;"> was </span><span style="font-family:Verdana;">normal. Conclusion: Needle EMG, F-wave and H-Reflex examinations are pr</span><span style="font-family:Verdana;">edictably normal in patients with non-dermatomal, non-neuropathic sensory symptoms with normal neurologic examination and without history of pre</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">existing medical and surgical disorders. A good neurologic examination sh</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ould determine the need to perform these procedures. Our findings have important diagnostic, therapeutic, prognostic, economic and legal implications</span></span></span><span style="font-family:Verdana;">.</span>
文摘目的:探究24 h动态心电图(DCG)中房性快速心律失常与心电图P波时限及离散度的相关性。方法:选取2021年1月—2024年5月在厦门大学附属第一医院同时行常规心电图、24 h DCG检查的320例患者作为研究对象,将24 h DCG检查中出现房性心律失常的216例作为异常组,根据房性快速心律失常表现,将患者分为偶发房性早搏组、频发房性早搏组、短阵房速组、阵发性房颤组、阵发性房扑组,纳入两项检查均正常的104例患者作为正常组。比较正常组、异常组的心电图检测指标[P波最大时限(Pmax)、P波离散度(Pd)];采用多因素logistic回归分析24 h DCG中房性快速心律失常发生的影响因素;采用Spearman相关性分析模型,探讨Pmax、Pd与24 h DCG中房性快速心律失常发生的相关性。结果:异常组中偶发房性早搏组、频发房性早搏组、短阵房速组、阵发性房颤组、阵发性房扑组患者Pmax、Pd水平均高于正常组,差异有统计学意义(P<0.05);且短阵房速组、阵发性房颤组、阵发性房扑组患者Pmax、Pd水平均高于偶发房性早搏组,差异有统计学意义(P<0.05);多因素logistic回归分析结果显示,Pmax、Pd均为房性快速心律失常发生的危险因素(P<0.05);Spearman相关分析结果显示,Pmax、Pd水平与房性快速心律失常发生呈正相关(P<0.001)。结论:房性快速心律失常患者心电图常表现为Pmax、Pd水平升高,且Pmax、Pd异常水平与房性快速心律失常情况的发生具有显著相关性,临床可通过关注高危患者上述指标状况早期预警房性心律失常的发生。
文摘Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synthesized process is simple, low-cost and possible for application on transparent electrodes, gas sensors and thin film resistors. Analytical methods such as Raman spectroscopy, transmission electron microscopy (TEM) and four points prove resistivity measurement and UV-VIS-NIR spectroscopy were employed to characterize properties of the graphene films. The formation of multilayer of graphene on silicon substrate was confirmed by Raman spectroscopy and TEM. It is possible to grow graphene directly on silicon substrate (without using catalyst) due to high radical density of MW SWP CVD. In addition, we also observed that the hydrogen had significant role for quality of graphene.
