目的:探讨双背侧前额叶高频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)治疗精神分裂症难治性阴性症状的疗效和安全性,并观察不良反应。方法:本研究为双盲随机对照临床试验。研究对象来源于2002年11月1日至2003...目的:探讨双背侧前额叶高频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)治疗精神分裂症难治性阴性症状的疗效和安全性,并观察不良反应。方法:本研究为双盲随机对照临床试验。研究对象来源于2002年11月1日至2003年12月31日期间就诊于北京大学第六医院和北京安定医院的门诊和住院患者,符合美国精神疾病诊断与统计手册第4版(Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition,DSM-IV)中精神分裂症诊断标准。23例以难治性阴性症状为主的精神分裂症患者随机分为rTMS治疗组(n=12)和对照组(n=11),分别给予10次20Hz rTMS真刺激和伪刺激治疗,治疗期间维持原有抗精神病药种类及剂量不变。采用阳性和阴性症状量表(Positive and Negative Syndrome Scale,PANSS)评估临床症状,采用治疗中需处理的不良反应症状量表(Treatment Emergent Symptom Scale,TESS)及其他检查评估不良反应。结果:23例患者均完成治疗。治疗组有效率高于对照组(34%vs.17%,P<0.05)。未观察到明显不良反应。结论:抗精神病药合并20Hz双背侧前额叶重复经颅磁刺激治疗精神分裂症难治性阴性症状有效、安全。展开更多
The mirror extending approach proposed by Zhao and Huang in EMD method is improved in this paper. Mirror extending manner of data is kept unchanged, but the approach for determining envelopes is changed. When the end ...The mirror extending approach proposed by Zhao and Huang in EMD method is improved in this paper. Mirror extending manner of data is kept unchanged, but the approach for determining envelopes is changed. When the end of data is obviously not extremum, the envelope is determined by the first inner extremum and the image value in the mirror, ignoring the value on the end. This improvement eliminates the frequency compression near the end and decreases the error. Meanwhile, tridiagonal equations are used and the calculation speed is much increased. The temporal process curve is more important in reflecting the real physical process and comparable with other phenomena. Frequency mixing in IMFs makes it impossible. A high frequency reconstruction (HFR) approach is proposed to eliminate common frequency mixing and reconstruct an IMF with all high frequency portions. By this approach, the IMFs without frequency mixing are obtained to express significative processes. The high frequency information restored in high frequency IMF can be extracted by general spectrum method. After obtaining IMFs by EMD method, some of the theoretical and technological issues still exist when using the IMFs. The consistency of IMFs with real physical process is discussed in detail. By virtue of the approach proposed in this paper, the EMD method can be widely used in various fields.展开更多
Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the ex...Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the excitability of cortical neurons. However, there are few studies concerning the use of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper-limb motor function after cerebral infarction. We hypothesized that different frequencies of repetitive transcranial magnetic stimulation in patients with cerebral infarction would produce different effects on the recovery of upper-limb motor function. This study enrolled 127 patients with upper-limb dysfunction during the subacute phase of cerebral infarction. These patients were randomly assigned to three groups. The low-frequency group comprised 42 patients who were treated with 1 Hz repetitive transcranial magnetic stimulation on the contralateral hemisphere primary motor cortex （M1）. The high-frequency group comprised 43 patients who were treated with 10 Hz repetitive transcranial magnetic stimulation on ipsilateral M1. Finally, the sham group comprised 42 patients who were treated with 10 Hz of false stimulation on ipsilateral M1. A total of 135 seconds of stimulation was applied in the sham group and high-frequency group. At 2 weeks after treatment, cortical latency of motor-evoked potentials and central motor conduction time were significantly lower compared with before treatment. Moreover, motor function scores were significantly improved. The above indices for the low- and high-frequency groups were significantly different compared with the sham group. However, there was no significant difference between the low- and high-frequency groups. The results show that low- and high-frequency repetitive transcranial magnetic stimulation can similarly improve upper-limb motor function in patients with cerebral infarction.展开更多
In recent years,the large-scale integration of re-newable energy sources represented by wind power and the widespread application of power electronic devices in power systems have led to the emergence of multi-frequen...In recent years,the large-scale integration of re-newable energy sources represented by wind power and the widespread application of power electronic devices in power systems have led to the emergence of multi-frequency oscillation problems covering multiple frequency segments,which seriously threaten system stability and restrict the accommodation of renewable energy.The oscillation problems related to renewable energy integration have become one of the most popular topics in the field of wind power integration and power system stability research.It has received extensive attention from both academia and industries with many promising research results achieved to date.This paper first analyzes several typical multi-frequency oscillation events caused by large-scale wind power integration in domestic and foreign projects,then studies the multi-frequency oscillation problems,including wind turbine’s shafting torsional oscillation,sub/super-synchronous oscillation and high frequency resonance.The state of the art is systematically summarized from the aspects of oscillation mechanism,analysis methods and mitigation measures,and the future research directions are explored.展开更多
使用局部放电检测方法检测高压电缆终端内的绝缘缺陷问题。根据高压电缆终端产生局部放电的不同信号传播特性,设计基于高频HF(High Frequency)和超高频UHF(Ultra High Frequency)检测原理的局部放电信号传感器以及便携式检测设备等,并...使用局部放电检测方法检测高压电缆终端内的绝缘缺陷问题。根据高压电缆终端产生局部放电的不同信号传播特性,设计基于高频HF(High Frequency)和超高频UHF(Ultra High Frequency)检测原理的局部放电信号传感器以及便携式检测设备等,并开展现场电缆终端的局部放电在线检测。高频电流传感器可耦合接地线上流过的高频放电电流信号,而超高频传感器则感应空间传播电磁波信号。利用便携式检测设备实时采集数据结果,通过提取脉冲信号波形和多传感器信号联合比较分析等手段,对检测到的脉冲信号进行区分,排除外界干扰,分辨来自电缆终端内部的真实局部放电信号。现场检测结果表明,基于HF和UHF的局部放电联合分析方法,能够提高电缆局部放电辨别的准确性和有效性。展开更多
文摘目的:探讨双背侧前额叶高频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)治疗精神分裂症难治性阴性症状的疗效和安全性,并观察不良反应。方法:本研究为双盲随机对照临床试验。研究对象来源于2002年11月1日至2003年12月31日期间就诊于北京大学第六医院和北京安定医院的门诊和住院患者,符合美国精神疾病诊断与统计手册第4版(Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition,DSM-IV)中精神分裂症诊断标准。23例以难治性阴性症状为主的精神分裂症患者随机分为rTMS治疗组(n=12)和对照组(n=11),分别给予10次20Hz rTMS真刺激和伪刺激治疗,治疗期间维持原有抗精神病药种类及剂量不变。采用阳性和阴性症状量表(Positive and Negative Syndrome Scale,PANSS)评估临床症状,采用治疗中需处理的不良反应症状量表(Treatment Emergent Symptom Scale,TESS)及其他检查评估不良反应。结果:23例患者均完成治疗。治疗组有效率高于对照组(34%vs.17%,P<0.05)。未观察到明显不良反应。结论:抗精神病药合并20Hz双背侧前额叶重复经颅磁刺激治疗精神分裂症难治性阴性症状有效、安全。
文摘The mirror extending approach proposed by Zhao and Huang in EMD method is improved in this paper. Mirror extending manner of data is kept unchanged, but the approach for determining envelopes is changed. When the end of data is obviously not extremum, the envelope is determined by the first inner extremum and the image value in the mirror, ignoring the value on the end. This improvement eliminates the frequency compression near the end and decreases the error. Meanwhile, tridiagonal equations are used and the calculation speed is much increased. The temporal process curve is more important in reflecting the real physical process and comparable with other phenomena. Frequency mixing in IMFs makes it impossible. A high frequency reconstruction (HFR) approach is proposed to eliminate common frequency mixing and reconstruct an IMF with all high frequency portions. By this approach, the IMFs without frequency mixing are obtained to express significative processes. The high frequency information restored in high frequency IMF can be extracted by general spectrum method. After obtaining IMFs by EMD method, some of the theoretical and technological issues still exist when using the IMFs. The consistency of IMFs with real physical process is discussed in detail. By virtue of the approach proposed in this paper, the EMD method can be widely used in various fields.
基金several colleague therapists of the Rehabilitation Medicine Department of the Affiliated Hospital of Qingdao University of China for their support and selfless help
文摘Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the excitability of cortical neurons. However, there are few studies concerning the use of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper-limb motor function after cerebral infarction. We hypothesized that different frequencies of repetitive transcranial magnetic stimulation in patients with cerebral infarction would produce different effects on the recovery of upper-limb motor function. This study enrolled 127 patients with upper-limb dysfunction during the subacute phase of cerebral infarction. These patients were randomly assigned to three groups. The low-frequency group comprised 42 patients who were treated with 1 Hz repetitive transcranial magnetic stimulation on the contralateral hemisphere primary motor cortex （M1）. The high-frequency group comprised 43 patients who were treated with 10 Hz repetitive transcranial magnetic stimulation on ipsilateral M1. Finally, the sham group comprised 42 patients who were treated with 10 Hz of false stimulation on ipsilateral M1. A total of 135 seconds of stimulation was applied in the sham group and high-frequency group. At 2 weeks after treatment, cortical latency of motor-evoked potentials and central motor conduction time were significantly lower compared with before treatment. Moreover, motor function scores were significantly improved. The above indices for the low- and high-frequency groups were significantly different compared with the sham group. However, there was no significant difference between the low- and high-frequency groups. The results show that low- and high-frequency repetitive transcranial magnetic stimulation can similarly improve upper-limb motor function in patients with cerebral infarction.
基金This work was supported by the National Natural Science Foundation of China(No.51577174).
文摘In recent years,the large-scale integration of re-newable energy sources represented by wind power and the widespread application of power electronic devices in power systems have led to the emergence of multi-frequency oscillation problems covering multiple frequency segments,which seriously threaten system stability and restrict the accommodation of renewable energy.The oscillation problems related to renewable energy integration have become one of the most popular topics in the field of wind power integration and power system stability research.It has received extensive attention from both academia and industries with many promising research results achieved to date.This paper first analyzes several typical multi-frequency oscillation events caused by large-scale wind power integration in domestic and foreign projects,then studies the multi-frequency oscillation problems,including wind turbine’s shafting torsional oscillation,sub/super-synchronous oscillation and high frequency resonance.The state of the art is systematically summarized from the aspects of oscillation mechanism,analysis methods and mitigation measures,and the future research directions are explored.
文摘使用局部放电检测方法检测高压电缆终端内的绝缘缺陷问题。根据高压电缆终端产生局部放电的不同信号传播特性,设计基于高频HF(High Frequency)和超高频UHF(Ultra High Frequency)检测原理的局部放电信号传感器以及便携式检测设备等,并开展现场电缆终端的局部放电在线检测。高频电流传感器可耦合接地线上流过的高频放电电流信号,而超高频传感器则感应空间传播电磁波信号。利用便携式检测设备实时采集数据结果,通过提取脉冲信号波形和多传感器信号联合比较分析等手段,对检测到的脉冲信号进行区分,排除外界干扰,分辨来自电缆终端内部的真实局部放电信号。现场检测结果表明,基于HF和UHF的局部放电联合分析方法,能够提高电缆局部放电辨别的准确性和有效性。
