BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs ...BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs pulse-width-modulated (PWM) voltage that applies a higher average voltage to a larger protein species. BlotMan can be controlled not only by its custom-made interface but also by a smart phone via Bluetooth technology. In this study, we examined effects of PWM signals (50%, 60%, and 80% duty cycle) on transfer efficiency and signal intensity in comparison to a constant voltage signal (100% duty cycle). The result revealed that in response to the same average voltage of 150 V, a lower duty cycle with a higher maximum voltage increased transfer efficiency as well as sharpness of transferred proteins. We validated BlotMan’s capability using a chondrosarcoma cell line (SW1353 cells) and a breast cancer cell line (MDA-MB231 cells) in response to antitumor chemical agents. BlotMan successfully generated 5 membranes from a single gel and detected 5 protein species such as c-Src, eukaryotic translation initiation factor 2 alpha (eIF2), phosphorylated eIF2, lamin B, and actin. Collectively, we demonstrated herein that BlotMan reduces an amount of protein samples by generating multiple membranes from a single gel and improving signal intensity with PWM voltage signals.展开更多
Converters with pulse width modulation are used for connections between the direct current （DC） and alternating current （AC） networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for power...Converters with pulse width modulation are used for connections between the direct current （DC） and alternating current （AC） networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for powering induction furnaces, in audio technique. Spectrum of signals sampled by pulse amplitude modulation and output voltage spectrum of the converter with pulse width modulation have similar properties. Spectrum of signals sampled by pulse amplitude modulation contains a harmonic of frequency equal to the frequency of the modulating signal and the harmonics of frequencies equal to the sum of frequency of the modulating signal and multiples of the sampling frequency. The output voltage spectrum of the converter with bipolar pulse width modulation contains harmonic of frequency equal to the frequency of the modulating signal and harmonics of frequencies equal to sum of the frequency of the modulating signal and multiples of the frequency of the carrier signal. It also contains harmonics of frequencies equal to the sum of the multiples of the frequency of the modulating signal and the multiples of the carrier signal. The comparison analysis was carried out for the harmonics of the output voltage of the converter with bipolar pulse width modulation in time domain. The dependency of the amplitudes and frequency spectrum on the wave forms of the carrier signal and modulating signal was shown. Similarity of the output voltage spectrum of the converter and signal spectrum sampled by the pulse width modulation was also shown. Key words： Output voltage converter with bipolar pulse width modulation, spectral analysis, Fourier series, carrier signal, reference signal.展开更多
以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。...以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。首先介绍了3L-ANPC变流器拓扑结构中Si C-MOSFET和Si-IGBT器件的2种组合模式及3种调制方式,然后对3L-ANPC变流器拓扑共模噪声传输机理进行分析,基于分析建立了包含寄生参数和噪声源的EMI模型,并推导出每种调制方式下传导路径的阻抗表达式,得到了共模传导路径阻抗特性曲线。最终通过实验验证了3种调制方式下器件混合型3L-ANPC变流器拓扑共模噪声的分析结论。展开更多
The four-level nested neutral-point-clamped(4L-NNPC)inverter is a competitive topology among the various medium-voltage multilevel converters,and its main issue is flying-capacitor voltage unbalance.In this article,a ...The four-level nested neutral-point-clamped(4L-NNPC)inverter is a competitive topology among the various medium-voltage multilevel converters,and its main issue is flying-capacitor voltage unbalance.In this article,a novel carrier-interleaved pulse width modulation(CIPWM)method that satisfies the volt-sec balance principle is proposed with an advanced carrier distribution rule.By adopting the proposed CIPWM method,the redundant switching states of 4L-NNPC inverters can be evenly distributed into the output PWM waveform in each carrier period,and natural flying-capacitor voltage balance can be achieved.Furthermore,an active balancing strategy is also proposed to eliminate the voltage unbalance caused by nonideal factors,which is realized by simply adjusting the duty cycle and with no need to adjust the redundant switching states for 4L-NNPC inverters.The simulation and experimental results verify the effectiveness of the proposed CIPWM method and the flying-capacitor voltage balancing strategy.展开更多
文摘BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs pulse-width-modulated (PWM) voltage that applies a higher average voltage to a larger protein species. BlotMan can be controlled not only by its custom-made interface but also by a smart phone via Bluetooth technology. In this study, we examined effects of PWM signals (50%, 60%, and 80% duty cycle) on transfer efficiency and signal intensity in comparison to a constant voltage signal (100% duty cycle). The result revealed that in response to the same average voltage of 150 V, a lower duty cycle with a higher maximum voltage increased transfer efficiency as well as sharpness of transferred proteins. We validated BlotMan’s capability using a chondrosarcoma cell line (SW1353 cells) and a breast cancer cell line (MDA-MB231 cells) in response to antitumor chemical agents. BlotMan successfully generated 5 membranes from a single gel and detected 5 protein species such as c-Src, eukaryotic translation initiation factor 2 alpha (eIF2), phosphorylated eIF2, lamin B, and actin. Collectively, we demonstrated herein that BlotMan reduces an amount of protein samples by generating multiple membranes from a single gel and improving signal intensity with PWM voltage signals.
文摘Converters with pulse width modulation are used for connections between the direct current （DC） and alternating current （AC） networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for powering induction furnaces, in audio technique. Spectrum of signals sampled by pulse amplitude modulation and output voltage spectrum of the converter with pulse width modulation have similar properties. Spectrum of signals sampled by pulse amplitude modulation contains a harmonic of frequency equal to the frequency of the modulating signal and the harmonics of frequencies equal to the sum of frequency of the modulating signal and multiples of the sampling frequency. The output voltage spectrum of the converter with bipolar pulse width modulation contains harmonic of frequency equal to the frequency of the modulating signal and harmonics of frequencies equal to sum of the frequency of the modulating signal and multiples of the frequency of the carrier signal. It also contains harmonics of frequencies equal to the sum of the multiples of the frequency of the modulating signal and the multiples of the carrier signal. The comparison analysis was carried out for the harmonics of the output voltage of the converter with bipolar pulse width modulation in time domain. The dependency of the amplitudes and frequency spectrum on the wave forms of the carrier signal and modulating signal was shown. Similarity of the output voltage spectrum of the converter and signal spectrum sampled by the pulse width modulation was also shown. Key words： Output voltage converter with bipolar pulse width modulation, spectral analysis, Fourier series, carrier signal, reference signal.
文摘以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。首先介绍了3L-ANPC变流器拓扑结构中Si C-MOSFET和Si-IGBT器件的2种组合模式及3种调制方式,然后对3L-ANPC变流器拓扑共模噪声传输机理进行分析,基于分析建立了包含寄生参数和噪声源的EMI模型,并推导出每种调制方式下传导路径的阻抗表达式,得到了共模传导路径阻抗特性曲线。最终通过实验验证了3种调制方式下器件混合型3L-ANPC变流器拓扑共模噪声的分析结论。
基金supported by Beijing Natural Science Foundation under Grant L242006.
文摘The four-level nested neutral-point-clamped(4L-NNPC)inverter is a competitive topology among the various medium-voltage multilevel converters,and its main issue is flying-capacitor voltage unbalance.In this article,a novel carrier-interleaved pulse width modulation(CIPWM)method that satisfies the volt-sec balance principle is proposed with an advanced carrier distribution rule.By adopting the proposed CIPWM method,the redundant switching states of 4L-NNPC inverters can be evenly distributed into the output PWM waveform in each carrier period,and natural flying-capacitor voltage balance can be achieved.Furthermore,an active balancing strategy is also proposed to eliminate the voltage unbalance caused by nonideal factors,which is realized by simply adjusting the duty cycle and with no need to adjust the redundant switching states for 4L-NNPC inverters.The simulation and experimental results verify the effectiveness of the proposed CIPWM method and the flying-capacitor voltage balancing strategy.
