Browsing by Issue Date, starting with "2019-12-25"

Now showing 1 - 20 of 6113

Utilization of low-melting temperature alloy with confined seal for reducing thermal contact resistance
(2019-12-25)
Chu, Wen-Xiao
;
Tseng, Po-Hsiang
;
Wang, Chi-Chuan
;
機械工程學系
;
Department of Mechanical Engineering
This paper investigates a novel design of thermal interface material (TIM) using low-melting temperature alloy (LMTA) with confined seal. For solid TIM like indium foil, the thermal contact resistance is reduced with the rise with contact pressure, and an apparent hysteresis phenomenon may occur during loading/unloading of contact pressure. For the solid-state TIM, the indium TIM outperforms those of copper, lead and tin TIMs. The molten LMTA can further reduce the thermal contact resistance, however, the overflow and dislocation problems are observed. Hence, a novel confined design by using LMTA with an annular metal seal is proposed that can completely prevent aforementioned problems. Yet the reliability of the novel TIM is also investigated after hundred thermal cycles.
Effect of nonuniform pin size on heat transfer in a rotating rectangular channel with pin-fin arrays
(2019-12-25)
Hung, Shuo-Cheng
;
Huang, Szu-Chi
;
Liu, Yao-Hsien
;
機械工程學系
;
Department of Mechanical Engineering
Internal channels to cool the trailing edges of gas turbine blades were typically installed with pin-fin arrays for higher heat transfer enhancement. In this study, the heat transfer characteristics in a rotating rectangular channel (aspect ratio = 4:1) with differently sized pin-fin arrays were experimentally investigated. Liquid crystal thermography was used to measure heat transfer on the endwall in a staggered pin-fin array at a channel orientation of 135 degrees. The staggered array was composed of four or three pins in a row. Pins of varying diameters were inserted in every row exhibiting four pins; either two or four pins were replaced. The rotation numbers ranged from 0 to 0.33, and the Reynolds numbers ranged from 10,000 to 20,000. The results revealed that flow acceleration, separation, and wake flow contributed to various heat transfer contours. Larger pins contributed to higher local flow velocities through fin spacing and produced higher heat transfer distributions. The effect of rotation improved heat transfer enhancement on both trailing and leading surfaces. The friction factor ratio increased when more large-sized pins were installed in the array.
Mechanism of Photocatalytic CO2 Reduction by Bismuth-Based Perovskite Nanocrystals at the Gas-Solid Interface
(2019-12-25)
Bhosale, Sumit S.
;
Kharade, Aparna K.
;
Jokar, Efat
;
Fathi, Amir
;
Chang, Sue-min
We report here a series of nontoxic and stable bismuth-based perovskite nanocrystals (PeNCs) with applications for photocatalytic reduction of carbon dioxide to methane and carbon monoxide. Three bismuth-based PeNCs of general chemical formulas A(3)Bi(2)I(9), in which cation A(+) = Rb+ or Cs+ or CH3NH3+ (MK), were synthesized with a novel ultrasonication top-down method. PeNC of Cs3Bi2I9 had the best photocatalytic activity for the reduction of CO2 at the gas solid interface with formation yields 14.9 mu mol g(-1) of methane and 77.6 mu mol g(-1) of CO, representing a much more effective catalyst than TiO2 (P25) under the same experimental conditions. The products of the photocatalytic reactions were analyzed using a gas chromatograph coupled with a mass spectrometer. According to electron paramagnetic resonance and diffuse-reflectance infrared spectra, we propose a reaction mechanism for photoreduction of CO2 via Bi-based PeNC photocatalysts to form CO, CH4, and other possible side products.
Analytical study for swimmers in a channel
(2019-12-25)
Farutin, A.
;
Wu, H.
;
Hu, W-F
;
Rafai, S.
;
Peyla, P.
There is an overabundance of microswimmers in nature, including bacteria, algae, mammalian cells and so on. They use flagellum, cilia or global shape changes (amoeboid motion) to move forward. In the presence of confining channels, these swimmers exhibit often non-trivial behaviours, such as accumulation at the wall, navigation and so on, and their swimming speed may be strongly influenced by the geometric confinement. Several numerical studies have reported that the presence of walls either enhances or reduces the swimming speed depending on the nature of the swimmer, and also on the confinement. The purpose of this paper is to provide an analytical explanation of several previously obtained numerical results. We treat the case of amoeboid swimmers and the case of squirmers having either a tangential (the classical situation) or normal velocity prescribed at the swimmer surface (pumper). For amoeboid motion we consider a quasi-circular swimmer which allows us to tackle the problem analytically and to extract the equations of the motion of the swimmer, with several explicit analytical or semi-analytical solutions. It is found that the deformation of the amoeboid swimmer as well as a high enough order effect due to confinement are necessary in order to account for previous numerical results. The analytical theory accounts for several features obtained numerically also for non-deformable swimmers.
The numerical simulation with staggered alternation locations and multi-flow directions on the thermal performance of double-layer microchannel heat sinks
(2019-12-25)
Shen, Han
;
Xie, Gongnan
;
Wang, Chi-Chuan
;
機械工程學系
;
Department of Mechanical Engineering
The novel staggered flow alternation structure (SFAS) proposed in prior study has proved to be an efficient way in improving the overall thermal performance with acceptable pressure drop penalty in Double-layer Microchannel Heat Sinks (DMHSs). Based on the prior design, a further numerical investigation concerning the optimum location of SFAS in DMHSs is presented. The corresponding temperature fields, Nusselt number, flow fields, pressure drop and thermal characteristics are presented through verified computational mode. In addition, the effect of flow arrangements such as concurrent, upper-inlet/lower-inlet countercurrent arrangement on the thermal performance are studied in more details. The best thermal location of SFAS in the DMHSs is found to be based on the alterable locations and multi-flow directions. Yet, changing the location of staggered alternation structure does not lead to an appreciable rise of pressure drop penalty in DMHSs. However, the improvement in thermal performance for upper-inlet countercurrent arrangement is significant. Placing the SFAS in the middle of the DMHSs ensures the best overall thermal performance.
GLORIA企業講座：逸達生技甘良生總經理分享藥物開發經驗
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
陽明國際產學聯盟11月份「生醫領航方舟」企業講座，特別邀請對於臺灣、美國新藥開發產業有相當豐富經驗的逸達生技甘良生總經理蒞...
軟網校友共襄盛舉～花蓮鳳林盃軟式網球錦標賽
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
9月20-22日，由賴岡黌校友主辦之花蓮鳳林盃軟網賽第一屆國際賽事，邀集同曾是軟網隊的多位校友共襄盛舉，更別具校友團圓的意義（...
【生理所生涯座談】畢業不再ㄎㄎ
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
榮陞及獲獎訊息
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
校友中心收到許多陽明校友們的好消息分享，有獲獎喜訊、研究突破，以及步步高陞等，是陽明人的驕傲～
物輔系友會～回饋母系，鄭凱云主播蒞校演講
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
11月7日，物輔系友會新任會長卓裕森校友，特別邀請主播明星鄭凱云蒞校演講，並引領學弟妹了解工作上溝通的重要性（請點選照片開啟...
醫放系～系友會正式成立
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
11月23日，醫放系友會由創會會長侯貴圓校友召開第1屆第1次會員大會，眾校友參與外，更邀請多位嘉賓蒞臨，現場充滿濃濃喜氣（請點...
Topological Transition in a 3nm Thick Al Film Grown by Molecular Beam Epitaxy
(2019-12-27)
Kumar, Ankit
;
Su, Guan-Ming
;
Chang, Chau-Shing
;
Yeh, Ching-Chen
;
Wu, Bi-Yi
We have performed detailed transport measurements on a 3nm thick (as-grown) Al film on GaAs prepared by molecular beam epitaxy (MBE). Such an epitaxial film grown on a GaAs substrate shows the Berezinskii-Kosterlitz-Thouless (BKT) transition, a topological transition in two dimensions. Our experimental data shows that the MBE-grown Al nanofilm is an ideal system for probing interesting physical phenomena such as the BKT transition and superconductivity. The increased superconductor transition temperature (similar to 2.4K) compared to that of bulk Al (1.2K), together with the ultrathin film quality, may be advantageous for future superconductor-based quantum devices and quantum information technology.
【明(109)年校友回娘家活動預告】
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
哇！襪娃創作的心理療效
(國立陽明大學, 2019-12-27)
張麗君
;
陽明電子報編輯小組
【王信二教授退休歡送會】
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
【生醫領航方舟】企業講座第十場
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
【生理醫學講座】The Biotechnology Market Trends and Opportunities by 2025
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
【學術演講】Causes of and Countermeasures for Intradialytic Hypotension
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
【生藥所演講資訊】尤泰元博士主講
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
醫工學院兩培訓團隊，榮獲「2019生技創新創業競賽」四大獎
(國立陽明大學, 2019-12-27)
陽明電子報編輯小組
本校醫工學院「生醫產業創新創業人才培育課程」學員，參加教育部「生醫產業與新農業創新創業競賽」，今年再度榮獲四個大獎的肯定...