High Power Density Asymmetrical Full-Bridge Soft-Switching Inverter

Pei-Chin Chi,Cheng-Yen Chou,Marojahan Tampubolon,Yao-Ching Hsieh,Jing-Yuan Lin,Huang-Jen Chiu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper presents a Zero-Voltage-Switching (ZVS) technique eliminating the switching loss on a proposed single phase bi-directional full-bridge Buck inverter in which asymmetrical filter topology and control scheme are for each arm. Here Metal-Oxide-Field-Effect- Transistor(MOSFET) is chosen as the switching device, an L₁-C₁ filter is connected across the full-bridge, an L₂ filter is connected in series to load or grid. While the arm connecting with the C₁ is controlled by the polarity of 50Hz sinusoid reference command and the arm connecting with the L₁ is controlled by a Pulse-Width-Modulation(PWM) signal modulated by sinusoid, the L₁-C₁ then operates as an output filter of Buck, and the succeeding L₂ filter further attenuates ripple current flowing to load or grid. The ZVS technique sets the L₁ inductance such low that its current flows bi-directionally within a switching period, then the bidirectional current with sufficiently high peaks in turn charge and discharge the output capacitance Coss of MOSFETs of the switching arm within floating time, defined as the duration when both MOSFETs of an arm are off, to let the MOSFETs D-S channels be turned on or off at the state that Coss are fully discharged to zero voltage, so ZVS of MOSFET is achieved. Under the ZVS operation without frequency proportional switching loss, the switching frequency is possible to be raised to high to compact the sizes of passive components and heat sink of the inverter for achieving high power density. Simulation and experiment have been carried out to verify the ZVS operation.

Evaluation of Malignancy Risk of Ampullary Tumors Detected by Endoscopy Using 2-[18F]FDG PET/CT

Chuang Pei-Ju,Wang Hsiu-Po,Tien Yu-Wen,Chin Wei-Shan,Hsieh Min-Shu,Chen Chieh-Chang,Hong Tzu-Chan,Ko Chi-Lun,Wu Yen-Wen,Cheng Mei-Fang 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.3

Objective: We aimed to investigate whether 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) can aid in evaluating the risk of malignancy in ampullary tumors detected by endoscopy. Materials and Methods: This single-center retrospective cohort study analyzed 155 patients (79 male, 76 female; mean age, 65.7 ± 12.7 years) receiving 2-[18F]FDG PET/CT for endoscopy-detected ampullary tumors 5–87 days (median, 7 days) after the diagnostic endoscopy between June 2007 and December 2020. The final diagnosis was made based on histopathological findings. The PET imaging parameters were compared with clinical data and endoscopic features. A model to predict the risk of malignancy, based on PET, endoscopy, and clinical findings, was generated and validated using multivariable logistic regression analysis and an additional bootstrapping method. The final model was compared with standard endoscopy for the diagnosis of ampullary cancer using the DeLong test. Results: The mean tumor size was 17.1 ± 7.7 mm. Sixty-four (41.3%) tumors were benign, and 91 (58.7%) were malignant. Univariable analysis found that ampullary neoplasms with a blood-pool corrected peak standardized uptake value in earlyphase scan (SUVe) ≥ 1.7 were more likely to be malignant (odds ratio [OR], 16.06; 95% confidence interval [CI], 7.13–36.18; P < 0.001). Multivariable analysis identified the presence of jaundice (adjusted OR [aOR], 4.89; 95% CI, 1.80–13.33; P = 0.002), malignant traits in endoscopy (aOR, 6.80; 95% CI, 2.41–19.20; P < 0.001), SUVe ≥ 1.7 in PET (aOR, 5.43; 95% CI, 2.00–14.72; P < 0.001), and PET-detected nodal disease (aOR, 5.03; 95% CI, 1.16–21.86; P = 0.041) as independent predictors of malignancy. The model combining these four factors predicted ampullary cancers better than endoscopic diagnosis alone (area under the curve [AUC] and 95% CI: 0.925 [0.874–0.956] vs. 0.815 [0.732–0.873], P < 0.001). The model demonstrated an AUC of 0.921 (95% CI, 0.816–0.967) in candidates for endoscopic papillectomy. Conclusion: Adding 2-[18F]FDG PET/CT to endoscopy can improve the diagnosis of ampullary cancer and may help refine therapeutic decision-making, particularly when contemplating endoscopic papillectomy.

Effectiveness of Cognitive-behavioral Program on Pain and Fear in School-aged Children Undergoing Intravenous Placement

Yi-Chuan Hsieh,Su-Fen Cheng,Pei-Kwei Tsay,Wen-Jen Su,Yen-Hua Cho,Chi-Wen Chen 한국간호과학회 2017 Asian Nursing Research Vol.11 No.4

Purpose: This study aimed to evaluate the effects of cognitive-behavioral program on pain and medical fear in hospitalized school-aged children receiving intravenous (IV) placement. Methods: This study used an quasi-experimental design. Thirty-five participants were assigned to the experimental group and 33 to the control group in the acute internal medicine ward of a children's hospital. The cognitive-behavioral program entailed having the patients read an educational photo book about IV placement before the procedure and having them watch their favorite music video during the procedure. The outcome measures were numeric rating scales for pain intensity and fear during the procedure. Results: After applying the cognitive-behavioral program, the mean scores on pain and fear decreased in the experimental group. However, the difference in pain intensity between these two groups was nonsignificant. The intensity of fear in the experimental group was significantly lower than that in the control group. Conclusion: In this study, the cognitive-behavioral program used with school-aged hospitalized children promoted less fear during IV placement. The results of this study can serve as a reference for empirical nursing care and as care guidance for clinical IV injections involving children.

Eupafolin Suppresses P/Q-Type Ca²⁺ Channels to Inhibit Ca²⁺/ Calmodulin-Dependent Protein Kinase II and Glutamate Release at Rat Cerebrocortical Nerve Terminals

( Anna Chang ),( Chi-Feng Hung ),( Pei-Wen Hsieh ),( Horng-Huey Ko ),( Su-Jane Wang ) 한국응용약물학회 2021 Biomolecules & Therapeutics(구 응용약물학회지) Vol.29 No.6

Eupafolin, a constituent of the aerial parts of Phyla nodiflora, has neuroprotective property. Because reducing the synaptic release of glutamate is crucial to achieving pharmacotherapeutic effects of neuroprotectants, we investigated the effect of eupafolin on glutamate release in rat cerebrocortical synaptosomes and explored the possible mechanism. We discovered that eupafolin depressed 4-aminopyridine (4-AP)-induced glutamate release, and this phenomenon was prevented in the absence of extracellular calcium. Eupafolin inhibition of glutamate release from synaptic vesicles was confirmed through measurement of the release of the fluorescent dye FM 1-43. Eupafolin decreased 4-AP-induced [Ca²⁺]_i elevation and had no effect on synaptosomal membrane potential. The inhibition of P/Q-type Ca²⁺ channels reduced the decrease in glutamate release that was caused by eupafolin, and docking data revealed that eupafolin interacted with P/Q-type Ca²⁺ channels. Additionally, the inhibition of calcium/calmodulindependent protein kinase II (CaMKII) prevented the effect of eupafolin on evoked glutamate release. Eupafolin also reduced the 4-AP-induced activation of CaMK II and the subsequent phosphorylation of synapsin I, which is the main presynaptic target of CaMKII. Therefore, eupafolin suppresses P/Q-type Ca²⁺ channels and thereby inhibits CaMKII/synapsin I pathways and the release of glutamate from rat cerebrocortical synaptosomes.

Enhancing Training Program Completion Rates for 2-Year Registered Nursing Staff in Haematology-Oncology Wards through Innovative Evidence-Based Nursing

Yi-Chun Lin,Pei-Chi Hsieh,Pei-Chien Lu 한국간호과학회 2015 한국간호과학회 학술대회 Vol.2015 No.10

Long-term Care Nurses’ Communication Difficulties with People Living with Dementia in Taiwan

Jing-Jy Wang,Pei-Fang Hsieh,Chi-Jane Wang 한국간호과학회 2013 Asian Nursing Research Vol.7 No.3

Purpose: Impairments in word finding, language skills and memory in dementia patients increase the obstacles for health professionals to provide effective care. Although some research on communication with dementia patients has been done, no research that pre-assessed nurses’ difficulties in communicating with dementia patients has been identified. This study aims to explore nurses’ difficulties in communicating with patients who have dementia. Methods: This was a qualitative research using the phenomenological approach. Data were collected through in-depth interviews. Fifteen nurses with at least 6 months of dementia care experience participated in this study. Each interview was audio-taped and transcribed within 48 hours after each interview. Participants were asked to respond to the question, “Please describe the difficulties in communicating with patients who have dementia.”Results: Through content analysis, two themes, each with two subthemes emerged: Different language, including repetitive responses and lack of language consensus; blocked messages, including difficulty in accessing emotions and in understanding needs. Ineffective language refers to a lack of agreement dialect between the nurse and the patient while blocked messages refer to the inability of nurses to understand the true underlying meaning of messages the patients send out through verbal or nonverbal behaviors or expression. Conclusion: The results can serve as reference for planning dementia communication education for school curriculum to enhance student nurses’ communication abilities and for junior nurses working in long-term or acute care settings to increase nurses’ patient-centered communication abilities with the ultimate goal of improving quality of care for patients with dementia.

A DSP-Based Differential Boost Inverter with Maximum Power Point Tracking

Marojahan Tampubolon,Irwan Purnama,Pei-Chin Chi,Jing-Yuan Lin,Yao-Ching Hsieh,Huang-Jen Chiu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper presents a DSP-based differential boost inverter (DBI) with maximum power point tracking (MPPT) for photovoltaic (PV) applications. In a conventional DC/AC MPPT system, power of photovoltaic is delivered into two stages, they are DC/DC boost converter and buck type DC/AC inverter. A DC link capacitor appears between these two stages. Furthermore the system has higher complexity and costly than that of DC/AC MPPT system with a single stage boost inverter. Here, a single stage differential boost inverter is implemented. Since it can produce a sinusoidal output voltage higher than its DC voltage input, it is not only able to reduce the stage number of DC/AC MPPT system but also able to eliminate the DC link capacitor. The MPPT method employed in this study is P&O method. This technique is widely used due to its easy implementation, and unimportant extreme weather change consideration. To implement this technique, a digital signal processor (DSP) was used. In this paper, a review of DBI and MPPT implementation are presented. Finally a 400W laboratory prototype has been built. The result shows that the P&O MPPT method has been successfully implemented for various PV power and it can reach 95% maximum MPPT accuracy. In addition, the DBI is able to produce a sinusoidal output voltage at the various PV power conditions.

Microstructure and Abrasive Wear Properties of Fe-Cr-C Hardfacing Alloy Cladding Manufactured by Gas Tungsten Arc Welding (GTAW)

Jie-Hao Chen,Chih-Chun Hsieh,Pei-Shing Hua,Chia-Ming Chang,Chi-Ming Lin,Paxon Ti-Yuan Wu,Weite Wu 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.1

A series of Fe-Cr-C hardfacing alloys is deposited by gas tungsten arc welding and subjected to abrasive wear testing. Pure Fe with various amounts of CrC (Cr:C=4:1) powders are mixed as the fillers and used to deposit hardfacing alloys on low carbon steel. Depending on the various CrC additions to the alloy fillers,the claddings mainly contain hypoeutectic, near eutectic, or hypereutectic microstructures of austenite γ-Fe phase and (Cr,Fe)7C3 carbides on hardfacing alloys, respectively. When 30% CrC is added to the filler, the finest microstructure is achieved, which corresponds to the γ-Fe+(Cr,Fe)7C3 eutectic structure. With the addition of 35% and 40% CrC to the fillers, the results show that the cladding consists of the massive primary (Cr,Fe)7C3 as the reinforcing phase and interdendritic Fe+(Cr,Fe)7C3 eutectics as the matrix. The (Cr,Fe)7C3 carbide-reinforced claddings have high hardness and excellent wear resistance under abrasive wear test conditions. Concerning the abrasive wear feature observable on the worn surface, the formation and fraction of massive primary (Cr,Fe)7C3 carbides predominates the wear resistance of hardfacing alloys. Abrasive particles result in continuous plastic grooves when the cladding has primary γ-Fe phase in a hypoeutectic structure.