Browsing by Issue Date, starting with "2020-02-25"

Now showing 1 - 20 of 5614

Numerical investigation of thermal and hydraulic performance of shell and plate heat exchanger
(2020-02-25)
Abbas, Ali
;
Lee, Howard
;
Sengupta, Mash
;
Wang, Chi-Chuan
;
機械工程學系
Detailed single-phase performance of the shell and plate heat exchangers is presented in this study with corresponding chevron angles (beta) of 45 degrees and 75 degrees, respectively. Unlike those conventional plate heat exchanger, the thermofluids characteristics perform quite differently between shell and inner channel. For a larger chevron angle (75 degrees), the friction factor is comparable amid shell and inner channel. Yet the friction factor in the shell channel is much lower than that in inner channel at a smaller chevron angle (45 degrees). The shell channel contains more unidirectional flow pattern while some flow re-circulation may occur at the entrance/exit port of the inner channel. The flow pattern and temperature distribution in the shell channel are generally more uniform than those in inner channel. The shell channel with beta = 45 degrees shows a better overall performance for its much lower friction factor when the Reynolds number is low. The heat transfer performance for shell channel exceeds the inner channel appreciably when the chevron angle is high (75 degrees). The heat transfer performance depends on the corrugation aspect ratio, and an optimum ratio is derived. For the inner channel, the optimum value is around 0.75 while it is 0.53 for the shell channel.
Improvement on dehumidifier performance using a plastic assisted condenser
(2020-02-25)
Chu, Wen-Xiao
;
Chiu, Chuang-Hui
;
Wang, Chi-Chuan
;
機械工程學系
;
Department of Mechanical Engineering
This paper proposed a new design concept for improving daily moisture removal rate and energy-efficiency factor of a dehumidifier. The plastic straws with diameters of 12 mm, 8.0 mm and 6.0 mm are inserted between the evaporator and condenser as an assisted condenser. A total of four cases are experimentally investigated, and the numerical analysis is conducted to further explain the performance improvement mechanism. Compared to the original dehumidifier, the assisted condenser with twelve straws having a diameter of 12 mm can pronouncedly improve the moisture removal rate of the dehumidifier by 6.9-9.2% and 1.2-6.4% at the standard condition and over-loading condition, respectively. By reducing the straw diameter to 8.0 mm, the improvement is reduced and the assisted condenser even reveal deteriorated effect at a high fan speed condition. Yet more pronounced degradation is seen when introducing 8.0 mm straws having two rows with staggered layout. It can be explained from numerical analysis that the pressure drop across the assisted condenser plays an important role. The optimum design depends on the balance between the main airflow, entrained airflow, and the flow resistance of the assisted condenser.
Redeveloping a global MOOC to be more locally relevant: design-based research
(2020-02-26)
Chen, Ken-Zen
;
Oakley, Barbara
;
教育研究所
;
Institute of Education
This study demonstrated a globally and locally relevant MOOC design model. By redeveloping a culturally responsive MOOC based on the course "Learning How to Learn (LHTL)" on the Coursera, the researchers created a sister MOOC to meet the local needs of Chinese learners. In this three-year design-based research study, four major iterations were conducted: (1) to analyze and prototype culturally responsive course contents for Chinese MOOCs learners; (2 and 3) to redevelop, pilot, field-test, and improve the new MOOC; and (4) to develop research-supported instructional practice for continued growth. This research contributed to the study of MOOCs by providing a thorough understanding of the design principles of, and theoretical claims about, the development of a culturally responsive MOOC. We hope this effort will help underpin further studies involving culturally responsive and comparable sister courses to advance MOOC research.
Self-Powered, Self-Healed, and Shape-Adaptive Ultraviolet Photodetectors
(2020-02-26)
Tsai, Meng-Shian
;
Shen, Tien-Lin
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Wu, Hsing-Mei
;
Liao, Yu-Ming
;
Liao, Yu-Kuang
The emergence of self-healing devices in recent years has drawn a great amount of attention in both academics and industry. Self-healed devices can autonomically restore a rupture as unexpected destruction occurs, which can efficiently prolong the life span of the devices; hence, they have an enhanced durability and decreased replacement cost. As a result, integration of wearable devices with self-healed electronics has become an indispensable issue in smart wearable devices. In this study, we present the first self-powered, self-healed, and wearable ultraviolet (UV) photodetector based on the integration of agarose/poly(vinyl alcohol) (PVA) double network (DN) hydrogels, which have the advantages of good mechanical strength, self-healing ability, and tolerability of multiple types of damage. With the integration of a DN hydrogel substrate, the photodetector enables 90% of the initial efficiency to be restored after five healing cycles, and each rapid healing time is suppressed to only 10 s. The proposed device has several merits, including having an all spray coating, self-sustainability, biocompatibility, good sensitivity, mechanical flexibility, and an outstanding healing ability, which are all essential to build smart electronic systems. The unprecedented self-healed photodetector expands the future scope of electronic skin design, and it also offers a new platform for the development of next-generation wearable electronics.
劉冠澤、陳彥儒同學分獲「醫學生暑期研究計畫」競賽亞軍、傑作
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
由健康科學文教基金會與國家衛生研究院合辦之「第14屆醫學系學生暑期研究計畫」，日前公布競賽結果，本校醫學系五年級劉冠澤同學...
大手牽小手，青幼社反毒宣導
(國立陽明大學, 2020-02-27)
陳念平
;
陽明電子報編輯小組
依稀記得一次與教官的談話中，被問了一句：「念平，聽說你們青幼社專門帶國小生，那願不願意一起去石牌國小宣導反毒教育？」「好啊！當然可以！」雖然這件事情有點突然，但我還是馬上答應了！能向國小生宣導極為重要的反毒教育，對我們青幼社的夥伴們來說，是一件好玩又有意義的活動！
【生技醫療創新創業講座】知己知彼的募資準備
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
【健康一體研究中心演講】
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
科技部「愛因斯坦培植計畫」，神研所郭曉縈研究員入選
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
本校神經科學研究所研究員郭曉縈博士，專注於大腦基底核的神經系統研究，研究成果豐碩，陸續發表於”Nature Neuroscience”、”FA...
台灣腫瘤分割挑戰賽，陽明醫學系團隊獲第二
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
本校醫學系五年級高家祥、郭宜欣與黃玠淳同學組成的「Very Good Tumor」團隊，參加「第二屆台灣腫瘤分割挑戰賽」，使用預訓練（pr...
我們在同個世界中，共享健康
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
沒有什麼事情能夠比今年武漢新型冠狀病毒（COVID-19）疫情更能夠說明「One World, One Health」這個理念。就像當年金恩博士說的一...
【防疫大作戰，全民動起來】～防疫知識英語口說大賽
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
激勵工作士氣，優秀行政人員獲表揚
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
為激勵行政人員工作士氣，人事室於2月25日舉行「108年度優秀行政服務人員頒獎典禮」，表揚本年度「最佳服務獎」與「工作績優獎」...
【神研所40週年系列講座】
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
面對新冠肺炎，我可以有什麼準備？
(國立陽明大學, 2020-02-27)
王詠瑩
;
陽明電子報編輯小組
港澳生檢疫期滿，3/2順利開學
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
陽明即將於3月2日開學，近20名已抵台返校的港澳生，2月25日已完成14天居家檢疫。學校防疫小組指揮官郭旭崧校長與副指揮官蕭志建教...
On the Reduction of O-2 on Cathode Surfaces of Co-Corrin and Co-Porphyrin: A Computational and Experimental Study on Their Relative Efficiencies in H2O/H2O2 Formation
(2020-02-27)
Huang, Wen-Fei
;
Chang, Sun-Tang
;
Huang, Hsin-Chih
;
Wang, Chen-Hao
;
Chen, Li-Chyong
The mechanisms for O-2 reduction and H2P/H2O2 formation on Co-corrin and Co-porphyrin cathode surfaces of the proton exchange membrane fuel cell (PEMFC) systems have been studied by hybrid Hartree-Fock/density functional theory (B3LYP) calculations with the LANL2DZ basis set. The calculations show that the reduced Co-corrin with a single negative charge (Co-corrin(-)) is more reactive than the neutral Co-corrin and the doubly charged Co-corrin(2-). Both O-2 and O adsorptions are most stable on Co-corrin(-), rather than Co-corrin or Co-corrin(2-). The potential energy profiles show that the decomposition of O-2 on both Co-corrin and Co-corrin(-) can take place energetically favorably without thermal activation. The formation of H2O and H2O2 are predicted to occur by two separate reaction paths: the HO path and the HOO path. The HO path with H2O as the predominant product on the reduced Co-corrin(-) surface, the energetically favored surface, under operational cathodic conditions, which is consistent with recent experimental findings, wherein the PEMFCs with pyrolyzed vitamin B12 containing Co-corrin as catalysts loaded at the cathode, can deliver up to 14.5 A cm(-3) at 0.8 V with IR compensation. A similar calculation performed for a Co-porphyrin system shows a significantly less efficient O-2 reduction, consistent with the experiment results of the PEMFC power output studies.
【神研所學術演講】
(國立陽明大學, 2020-02-27)
陽明電子報編輯小組
Molecular beam epitaxy preparation and in situ characterization of FeTe thin films
(2020-02-28)
Pereira, V. M.
;
Wu, C. N.
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Liu, C. E.
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Liao, S-S
;
Chang, C. F.
We have synthesized Fe1+y Te thin films by means of molecular beam epitaxy (MBE) under Te-limited growth conditions. We found that epitaxial layer-by-layer growth is possible for a wide range of excess Fe values, wider than expected from what is known from studies on the bulk material. Using x-ray magnetic circular dichroism spectroscopy at the Fe L-2(,3) and Te M-4(,5) edges, we observed that films with high excess Fe contain ferromagnetic clusters while films with lower excess Fe remain nonmagnetic. Moreover, x-ray absorption spectroscopy showed that it is possible to obtain films with very similar electronic structure as that of a high quality bulk single crystal Fe-1.(14) Te. Our results suggest that MBE with Te-limited growth may provide an opportunity to synthesize FeTe films with smaller amounts of excess Fe as to come closer to a possible superconducting phase.
【2020山腰電影院】～致我們的青春好動
(國立陽明大學, 2020-02-28)
陽明電子報編輯小組