Analysis, Design, and Implementation of a High-Performance Rectifier

Wang, Chien-Ming,Tao, Chin-Wang,Lai, Yu-Hao The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A high-performance rectifier is introduced in this study. The proposed rectifier combines the conventional pulse width modulation, soft commutation, and instantaneously average line current control techniques to promote circuit performance. The voltage stresses of the main switches in the rectifier are lower than those in conventional rectifier topologies. Moreover, conduction losses of switches in the rectifier are certainly lower than those in conventional rectifier topologies because the power current flow path when the main switches are turned on includes two main power semiconductors and the power current flow path when the main switches are turned off includes one main power semiconductor. The rectifier also adopts a ZCS-PWM auxiliary circuit to derive the ZCS function for power semiconductors. Thus, the problem of switching losses and EMI can be improved. In the control strategy, the controller uses the average current control mode to achieve fixed-frequency current control with stability and low distortion. A prototype has been implemented in the laboratory to verify circuit theory.

A High Performance Soft-Switching AC/DC Converter

Chien-Ming Wang,Chang-Hua Lin,Chi-Hsiang Cheng,Bo-Han Wu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper introduced a high performance single stage soft-switching AC/DC converter. The introduced soft-switching AC/DC converter uses four switches fullbridge circuit construct to achieve the input power factor correction and the output DC voltage regulation. The introduced soft-switching AC/DC converter adopts interleaved operation mode in ac input side to reduce the input current harmonic and increase the supply power level. Moreover, the introduced soft-switching AC/DC converter can get soft-switching function on its main power switches without soft-switching auxiliary circuit. Thus, the cost of circuit in low. A simple phase-shift control strategy is used to synthesize a suitable low harmonics sinusoidal waveform for the ac input current and achieve well dynamic regulation. A design example of 1000W high performance DC power supply system is examined to assess its performance.

A Single-Stage Resonant Buck-Boost AC Voltage Regulator

Chien-Ming Wang,Chang-Hua Lin,Guan-Yu Chen 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper proposed a single-stage resonant buck-boost ac voltage regulator. The proposed regulator can output a voltage which is larger or lower than the input ac one and is dependence on depending on the instantaneous duty-ratio. This property is not found in the conventional single-stage ac voltage regulator that the ac output instantaneous voltage is always lower than the input ac voltage. The proposed ac voltage regulator uses a series-resonant circuit to configure adaptively the resonant voltage pulse trains. The proposed ac voltage synthesized the resonant voltage pulse trains following the input voltage amplitude to the synthesized sinusoidal waveform (SSW) before output filter. Because the SSW very closes sinusoidal waveform, the proposed ac voltage regulator can use a simple LC filter to filter the undesired harmonics and to get the sinusoidal voltage waveform with low total harmonic distortion (THD). The proposed ac voltage regulator is controlled by constant frequency pulse width modulation technique. Its control circuit is simple. A design example of a 600W proposed ac voltage regulator is examined to assess the system performance. Under rated output power, the power efficiency is over 91% and the total harmonic distortion (THD) is within 6%.

Analysis, Design, and Implementation of a High-Performance Rectifier

Chien-Ming Wang,Chin-Wang Tao,Yu-Hao Lai 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A high-performance rectifier is introduced in this study. The proposed rectifier combines the conventional pulse width modulation, soft commutation, and instantaneously average line current control techniques to promote circuit performance. The voltage stresses of the main switches in the rectifier are lower than those in conventional rectifier topologies. Moreover, conduction losses of switches in the rectifier are certainly lower than those in conventional rectifier topologies because the power current flow path when the main switches are turned on includes two main power semiconductors and the power current flow path when the main switches are turned off includes one main power semiconductor. The rectifier also adopts a ZCS-PWM auxiliary circuit to derive the ZCS function for power semiconductors. Thus, the problem of switching losses and EMI can be improved. In the control strategy, the controller uses the average current control mode to achieve fixed-frequency current control with stability and low distortion. A prototype has been implemented in the laboratory to verify circuit theory.

The Effect of Agomelatine in Behavioral and Psychological Symptoms of Dementia

Carol Sheei-Meei Wang(Carol Sheei-Meei Wang ),Kuo-Sheng Cheng(Kuo-Sheng Cheng),Chia-Hung Tang(Chia-Hung Tang),Ming-Chyi Pai(Ming-Chyi Pai),Pai-Lien Chen(Pai-Lien Chen),Pei-Fang Chien(Pei-Fang Chien) 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.4

Objective: Moderate and severe behavioral and psychological symptoms of dementia (BPSD) often need medical treatment to improve symptoms. Agomelatine is a selective melatonergic (MT1/MT2) agonist that has normalizing effects on disturbed circadian rhythms and disrupted sleep−wake cycles. Its activity of 5HT-2C receptor antagonism is associated with lessening depression and anxiety and increasing slow-wave sleep. Based on past clinical records and current findings it suggests that agomelatine can improve BPSD for patients. This retrospective cohort study was designed to compare the BPSD before and after using agomelatine. Methods: Records of dementia cases who had ever received agomelatine treatment for BPSD in a general hospital setting during the past 2.5 years were identified and reviewed. Scores from before and after 3 months of treatment with agomelatine were collected for Neuropsychiatric Inventory (NPI), Brief Psychiatric Rating Scale (BPRS), and Clinical Global Impression (CGI) to compare and analyze the difference of psychological and behavioral symptoms pre- and post-agomelatine used. Results: Records of 144 cases of dementia with BPSD who had ever used agomelatine from January 2015 to June 2017 were collected. All of the 112 cases had BPRS and CGI scores, of which 75 cases had additional NPI scores. Among these 112 cases, the BPRS and CGI scores were significantly improved in all types of dementia. NPI scores indicated that the use of agomelatine alleviated obvious symptoms and decreased overall distress, especially in the depression/poor mood, anxiety, and sleep/night behavior. Conclusion: It is consistent with an effective result of agomelatine in improving BPSD.

Intense X-ray induced formation of silver nanoparticles stabilized by biocompatible polymers

Wang, Chang-Hai,Liu, Chi-Jen,Wang, Cheng-Liang,Chien, Chia-Chi,Hwu, Y.,Liu, Ru-Shi,Yang, Chung-Shi,Je, Jung-Ho,Lin, Hong-Ming,Margaritondo, G. Springer-Verlag 2009 Applied physics. A, Materials science & processing Vol.97 No.2

Galangin Prevents Acute Hepatorenal Toxicity in Novel Propacetamol-Induced Acetaminophen-Overdosed Mice

Ming-Shiun Tsai,Chia-Chih Chien,Ting-Hui Lin,Chia-Chi Liu,Rosa Huang Liu,Hong-Lin Su,Yung-Tsung Chiu,Sue-Hong Wang 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.11

Acetaminophen (APAP) overdose causes severe liver and kidney damage. APAP-induced liver injury (AILI) represents the most frequent cause of drug-induced liver failure. APAP is relatively insoluble and can only be taken orally; however, its prodrug, propacetamol, is water soluble and usually injected directly. In this study, we examined the timedependent effects of AILI after propacetamol injection in mice. After analyses of alanine aminotransferase and aspartate aminotransferase activities and liver histopathology, we demonstrated that a novel AILI mouse model can be established by single propacetamol injection. Furthermore, we compared the protective and therapeutic effects of galangin with a known liver protective extract, silymarin, and the only clinical agent for treating APAP toxicity, N-acetylcysteine (NAC), at the same dose in the model mice. We observed that galangin and silymarin were more effective than NAC for protecting against AILI. However, only NAC greatly improved both the survival time and rate consequent to a lethal dose of propacetamol. To decipher the hepatic protective mechanism(s) of galangin, galangin pretreatment significantly decreased the hepatic oxidative stress, increased hepatic glutathione level, and decreased hepatic microsomal CYP2E1 levels induced by propacetamol injection. In addition, propacetamol injection also reproduced the probability of APAP-induced kidney injury (AIKI), appearing similar to a clinical APAP overdose. Only galangin pretreatment showed the protective effect of AIKI. Thus, we have established a novel mouse model for AILI and AIKI using a single propacetamol injection. We also demonstrated that galangin provides significant protection against AILI and AIKI in this mouse model.

Design Rule and System Parameters Compare between Multi-phase and Multi-lamp PWM Dimming Control for Backlight Inverter

Chien-Yeh Ho,Chien-Ming Wang,Chang-Hua Lin 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper proposes a novel multi-phase PWM dimming control scheme which possesses two-phase, four-phase, six-phase, and eight-phase for backlight inverter. Each phase driving circuit can control the lamp current of two ccfls at least. From the experimental results for four-phase and six-phase PWM dimming control, we got a conclusion which power efficiency η (%) is directly proportional to No. of phases and lamp current error E (%) is inversely proportional to No. of phases. Hence higher phases dimming will achieve uniform output lamp currents which is called current equalization. We develop a design rule which compare system parameters in multi-phase dimming control for backlight inverter. We conclude that the experimental results also can apply for two-phase and eight-phase PWM dimming control.

Surgical Outcomes and Predictive Factors in Patients With Detrusor Underactivity Undergoing Bladder Outlet Obstruction Surgery

Ming-Syun Chuang,Yin-Chien Ou,Yu-Sheng Cheng,Kuan-Yu Wu,Chang-Te Wang,Yuan-Chi Huang,Yao-Lin Kao 대한배뇨장애요실금학회 2024 International Neurourology Journal Vol.28 No.1

Purpose: This study was conducted to evaluate the efficacy of bladder outlet surgery in patients with detrusor underactivity (DU) and to identify factors associated with successful outcomes.Methods: We conducted a retrospective review of men diagnosed with DU in urodynamic studies who underwent bladder outlet surgery for lower urinary tract symptoms between May 2018 and April 2023. The International Prostate Symptom Score (IPSS) questionnaire, uroflowmetry (UFM), and multichannel urodynamic studies were administered. Successful treatment outcomes were defined as either an IPSS improvement of at least 50% or the regaining of spontaneous voiding in patients urethral catheterization prior to surgery.Results: The study included 93 male patients. Men diagnosed with significant or equivocal bladder outlet obstruction (BOO) experienced significant postoperative improvements in IPSS (from 20.6 to 6.0 and from 17.4 to 6.5, respectively), maximum urine flow rate (from 5.0 mL/sec to 14.4 mL/sec and from 8.8 mL/sec to 12.2 mL/sec, respectively) and voiding efficiency (from 48.8% to 86.0% and from 61.2% to 85.1%, respectively). However, in the group without obstruction, the improvements in IPSS and UFM results were not significant. The presence of detrusor overactivity (odds ratio [OR], 3.152; P=0.025) and preoperative urinary catheterization (OR, 2.756; P=0.040) were associated with favorable treatment outcomes. Conversely, an unobstructed bladder outlet was identified as a negative prognostic factor.Conclusions: In men with DU accompanied by equivocal or significant BOO, surgical intervention to alleviate the obstruction may enhance the IPSS, quality of life, and UFM results. However, those with DU and an unobstructed bladder outlet face a comparatively high risk of treatment failure. Preoperative detrusor overactivity and urinary catheterization are associated with more favorable surgical outcomes. Consequently, active deobstructive surgery should be considered for patients with DU who are experiencing urinary retention. Purpose: This study was conducted to evaluate the efficacy of bladder outlet surgery in patients with detrusor underactivity (DU) and to identify factors associated with successful outcomes. Methods: We conducted a retrospective review of men diagnosed with DU in urodynamic studies who underwent bladder outlet surgery for lower urinary tract symptoms between May 2018 and April 2023. The International Prostate Symptom Score (IPSS) questionnaire, uroflowmetry (UFM), and multichannel urodynamic studies were administered. Successful treatment outcomes were defined as either an IPSS improvement of at least 50% or the regaining of spontaneous voiding in patients urethral catheterization prior to surgery. Results: The study included 93 male patients. Men diagnosed with significant or equivocal bladder outlet obstruction (BOO) experienced significant postoperative improvements in IPSS (from 20.6 to 6.0 and from 17.4 to 6.5, respectively), maximum urine flow rate (from 5.0 mL/sec to 14.4 mL/sec and from 8.8 mL/sec to 12.2 mL/sec, respectively) and voiding efficiency (from 48.8% to 86.0% and from 61.2% to 85.1%, respectively). However, in the group without obstruction, the improvements in IPSS and UFM results were not significant. The presence of detrusor overactivity (odds ratio [OR], 3.152; P=0.025) and preoperative urinary catheterization (OR, 2.756; P=0.040) were associated with favorable treatment outcomes. Conversely, an unobstructed bladder outlet was identified as a negative prognostic factor. Conclusions: In men with DU accompanied by equivocal or significant BOO, surgical intervention to alleviate the obstruction may enhance the IPSS, quality of life, and UFM results. However, those with DU and an unobstructed bladder outlet face a comparatively high risk of treatment failure. Preoperative detrusor overactivity and urinary catheterization are associated with more favorable surgical outcomes. Consequently, active deobstructive surgery should be considered for patients with DU who are experiencing urinary retention.

Transient Knock Down of Grp78 Reveals Roles in Serum Ferritin Mediated Pro-inflammatory Cytokine Secretion in Rat Primary Activated Hepatic Stellate Cells

Wang, Chi-Mei,Li, Shan-Jen,Wu, Chi-Hao,Hu, Chien-Ming,Cheng, Hui-Wen,Chang, Jung-Su Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Chronic liver diseases, including cancer, are characterized by inflammation and elevated serum ferritin (SF). However, the causal-relationship remains unclear. This study used primary rat hepatic stellate cells (HSC) as a model to investigate effects of physiological SF concentrations (10, 100 and 1000 pM) because HSCs play a central role in the development and progression of liver fibrosis. Physiological concentrations of SF, either horse SF or human serum, induced pro-inflammatory cytokine $IL1{\beta}$, IL6 and $TNF{\alpha}$ secretion in rat activated HSCs (all p<0.05). By contrast, treatment did not alter activation marker ${\alpha}SMA$ expression. The presence of SF markedly enhanced expression of Grp78 mRNA (p<0.01). Furthermore, transient knock down of Grp78 by endotoxin EGF-SubA abolished SF-induced $IL1{\beta}$ and $TNF{\alpha}$ secretion in activated HSCs (all p<0.05). In conclusion, our results showed that at physiological concentrations SF functions as a pro-inflammatory mediator in primary rat HSCs. We also provide a molecular basis for the action of SF and identified Grp78-associated ER stress pathways as a novel potential therapeutic target for resolution of fibrosis and possible prevention of liver cancer.