Browsing by Issue Date, starting with "2019-10-01"

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Vapor-Solid Reaction Growth of Rutile TiO2 Nanorods and Nanowires for Li-Ion-Battery Electrodes
(2019-10-01)
Lee, Tzu-Yuan
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
;
應用化學系
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Department of Applied Chemistry
A new synthetic method to grow O-deficient rutile TiO2(s) nanorods (NRs) and nanowires (NWs) by a vapor-solid reaction growth method is developed. TiCl4(g) was employed to react with commercially supplied CaTiO3(s) (size 2-4 mu m) at 973 K under atmospheric pressure to generate TiO2(s) NRs (diameters 80-120 nm, lengths 1-4 mu m). The reaction employing TiCl4(g) and CaO(s) at 973 K also generated CaTiO3(s) (size 4-13 mu m) as the intermediate which reacted further with TiCl4(g) to produce NWs (diameters 80-120 nm, lengths 4-15 mu m). This is the first report of 1D rutile TiO2(s) nanostructure with such a high aspect ratio. Both of the NRs and the NWs, with compositions TiO1.81 and TiO1.65, respectively, were single crystals grown in the [001] direction. Their morphology was affected by the reaction temperature, the concentration of TiCl4(g), and the particle size of CaTiO3(s). The NRs and the NWs were investigated as anode materials for Li+-ion batteries. At constant current rates 1, 2, and 5 C (1 C = 170 mA g-1) for 100 cycles, the cycling (1.0-3.0 V) performance data of the NRs were 146, 123, and 104 mA h g(-1), respectively. On the other hand, the cycling performance data of the NWs were 120, 80, and 52 mA h g(-1), respectively. This is attributed to the high Li+ ion diffusion rate (D-Li(+)) of the NRs (29.52 x 10(-15) cm(2) s(-1)), which exceeds that of the NWs (8.61 x 10(-1)5 cm(2) s(-1)). Although the [001] growth direction of the NR crystals would provide the fastest channels for the diffusion of Li+ ions and enhance the battery capacity, the extremely long channels in the NWs could hamper the diffusion of the Li+ ions. The O-deficiency in the structure would increase the conductivity of the electrode material and improve the stable cycling stability of the batteries also. The long-term cycling test at 2 C for the battery constructed from the NRs retained 121 mA h g(-1) after 200 cycles and 99.2 mA h g(-1) after 800 cycles. The device has an excellent long-term cycling stability with a loss of only 0.04% per cycle.
Designing Environmentally Friendly High-zT Zn4Sb3 via Thermodynamic Routes
(2019-10-01)
Wu, Hsin-Jay
;
Wei, Pai-Chun
;
Su, Hui-Yi
;
Wang, Kuang-Kuo
;
Yen, Wan-Ting
Zn4Sb3-based compounds constitute a lead-free material family with a best thermoelectric figure of merit (zT) in the midtemperature range. Unlike being a stoichiometric compound, the mutual solubility of Zn and Sb elicits rich microstructures and the structural instability of Zn4Sb3. The solubility limit and neighboring phase relations are crucial for the delicate balance between the thermoelectric performance and phase stability of Zn4Sb3. In this work, we constructed the isothermal section of the Zn-Sb-In ternary phase diagram, built the zT map near the beta-Zn4Sb3 phase region, and showed that the formation of multiscale microstructures has a profound impact on the electronic and phonon transport properties and phase stability. A high-zT zone was identified near the phase boundary between the two-phase InSb + Zn5Sb4In2 and the three-phase Zn4Sb4+InSb+ Zn5Sb4In2 regions. A sample with a nominal composition of Zn-3.8 In0.2Sb3 exhibited an ultralow kappa(L) of 0.2 (W m(-1) K-1), an enhanced PF of 1.75 (mW m(-1) K-2), and a remarkable zT value of 1.8 at 698 K. These state-of-the-art thermoelectric properties were attributed to the simultaneous enhancement in phonon scattering and the carrier energy-filtering effect in a unique hierarchical microstructure, in which InSb nanoprecipitates are dispersed in Zn5Sb4In2 coarse grains, and the latter are embedded in the host matrix In-Zn4Sb3. These results opened an avenue for environmentally friendly cost-effective midtemperature thermoelectric materials.
Protective effect of angiotensin-neprilysin inhibition compared to angiotensin inhibition on ventricular arrhythmias in spontaneous hypertensive rats
(2019-10-01)
Lin, T. T. L.
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Sung, Y. L. S.
;
Syu, J. Y. S.
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Hsu, H. J. H.
;
Lin, K. Y. L.
Inter-Client Interference Cancellation for Full-Duplex Networks With Half-Duplex Clients
(2019-10-01)
Lin, Kate Ching-Ju
;
Hsu, Kai-Cheng
;
Wei, Hung-Yu
;
資訊工程學系
;
Department of Computer Science
Recent studies have experimentally shown the gains of full-duplex radios. However, due to its relatively higher cost and complexity, we can envision a more practical step in the network evolution is to have a full-duplex access point (AP) but keep the clients half-duplex. Unfortunately, the full-duplex gains can hardly be extracted in practice as the uplink transmission from a half-duplex client introduces inter-client interference to another downlink client. To address this issue, we present the design and implementation of IC2 (Inter-Client Interference Cancellation), the first physical layer solution that exploits the AP's full-duplex capability to actively cancel the interference at the downlink client. Such active cancellation not only improves the achievable capacity, but also better tolerates imperfect user pairing, simplifying the MAC design as a result. We build a prototype of IC2 on USRP-N200 and evaluate its performance via both testbed experiments and large-scale trace-driven simulations. The results show that, without IC2, about 60% of client pairs produce no gain from full-duplex transmissions, while, with IC2 the median gain of the achievable rate over conventional half-duplex networks can be 1.65x and 1.47x for 1- and 2-antenna scenarios, respectively, even when clients are simply paired randomly.
A Novel Three-Axial Magnetic-Piezoelectric MEMS AC Magnetic Field Sensor
(2019-10-01)
Yeh, Po-Chen
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Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
We report a novel three-axial magnetic-piezoelectric microelectromechanical systems (MEMS) magnetic field sensor. The sensor mainly consists of two sensing elements. Each of the sensing elements consists of a magnetic Ni thick film, a Pt/Ti top electrode, a piezoelectric lead zirconate titanate (PZT) thin film, a Pt/Ti bottom electrode, a SiO2 insulation layer, and a moveable Si MEMS diaphragm. When the sensor is subjected to an AC magnetic field oscillating at 7.5 kHz, a magnetic force interaction between the magnetic field and Ni thick film is produced. Subsequently, the force deforms and deflects the diaphragms as well as the PZT thin film deposited on the diaphragms. The deformation and deflection produce corresponding voltage outputs due to the piezoelectric effect. By analyzing the voltage outputs through our criterion, we can obtain details of the unknown magnetic fields to which the sensor is subjected. This achieves sensing of three-axial magnetic fields. The experimental results show that the sensor is able to sense three-axial magnetic fields ranging from 1 to 20 Oe, with X-axial, Y-axial, and Z-axial sensitivities of 0.156 mV(rms)/Oe, 0.156 mV(rms)/Oe, and 0.035 mV(rms)/Oe, respectively, for sensing element A and 0.033 mV(rms)/Oe, 0.044 mV(rms)/Oe, and 0.130 mV(rms)/Oe, respectively, for sensing element B.
A Single-Inductor Triple-Source Quad-Mode Energy-Harvesting Interface With Automatic Source Selection and Reversely Polarized Energy Recycling
(2019-10-01)
Chen, Po-Hung
;
Cheng, Hao-Chung
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Lo, Chih-Lun
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This paper presents a single-inductor triple-source quad-mode (SITSQM) energy-harvesting interface in a 0.18-mu m CMOS process. The proposed reversely polarized energy recycling (RPER) technique improves not only the conversion efficiency at low input voltage but also the system's output power range. The interface employs the buck-boost topology to convert energy from photovoltaic (PV) cells and a thermoelectric generator (TEG) to a regulated 1.2-V output. The proposed converter features four different operating modes, namely, harvesting, recycling, storing, and backup. The operating mode is automatically selected according to the input and load conditions using the automatic source selection mechanism. The experimental results demonstrate 25.3% efficiency improvement and 10x output power range extension from the proposed RPER technique. The proposed SITSQM converter automatically manages three harvesting sources with 82.1% peak conversion efficiency.
【活動花絮】資工系第三屆傑出系友得獎感言
(國立交通大學資訊學院, 2019-10)
林珮雯
本院於108 年4 月13 日舉辦「資工系第三屆傑出系友頒獎」歡慶交大校慶，遴選曾煥哲、蔡士傑、盧豐裕、杜書全、林榮賜、李俊廣、呂學森、黃士傑、林弘全、簡志宇等學長為傑出系友。
Synthesis of [3+3] beta-ketoenamine-tethered covalent organic frameworks (COFs) for high-performance supercapacitance and CO2 storage
(2019-10-01)
El-Mandy, Ahmed F. M.
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Hung, Ying-Hui
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Mansoure, Tharwat Hassan
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Yu, Hsiao-Hua
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Hsu, Yu-Shen
We report three new beta-ketoenamine-linked covalent organic frameworks (COFs) prepared through Schiff-base [3+3] polycondensations of 1,3,5-triformylphloroglucinol (TFP-3OHCHO) with three tris(aminophenyl)-presenting derivatives-featuring amino, carbazole, and pyridine units, respectively under solvothermal conditions. The resultant TFP-COFs possessed high BET specific surface area up to 686 m(2) g(-1) and excellent crystallinity, which showed excellent electrochemical specific capacitances (up to 291.1 F g(-1)) and CO2 uptake efficiency up to 200 mg g(-1) at 273 K. We propose the enhanced performance in supercapacitor and gas storage is owing to the conjugated enamine structures with redox-active triphenyl amino, carbazole, and pyridine moieties. In addition, we further investigate the formation mechanism of the spherical TFP-TPA COF by studying the morphological changes over time. The presence of more highly planar monomer units in the hexagonal structures of the resultant COFs led to stronger quadrupolar interaction with the included CO2 molecules. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Intelligent Photolithography Corrections Using Dimensionality Reductions
(2019-10-01)
Parashar, Parag
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Akbar, Chandni
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Rawat, Tejender S.
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Pratik, Sparsh
;
Butola, Rajat
With the shrinking of the IC technology node, optical proximity effects (OPC) and etch proximity effects (EPC) are the two major tasks in advanced photolithography patterning. Machine learning has emerged in OPC/EPC problems because conventional optical-solver-based OPC is time-consuming, and there is no physical model existing for EPC. In this work, we use dimensionality reduction (DR) algorithms to reduce the computation time of complex OPC/EPC problems while the prediction accuracy is maintained. Also, we implement a pure machine learning approach where the input masks are directly mapped to the output etched patterns. While one photolithographic mask can generate many experimental patterns at once, our pure ML-based approach can shorten the trial-and-error period in the photolithographic correction. Additionally, we demonstrate the automation in SEM images preprocessing using feature detection, and this facilitates intelligent manufacturing in semiconductor processing. The input vector dimensions are effectively reduced by two orders of magnitude while the observed mean squared error is not affected significantly. The computation runtime is reduced from 4804 s of the baseline calculation to 10 s-200 s The MSE values changed from the baseline 0.037 to 0.037 for singular value decomposition (SVD), to 0.039 for independent component analysis (ICA), and to 0.035 for factor analysis (FA).
LTPS Active Pixel Circuit With Threshold Voltage Compensation for X-Ray Imaging Applications
(2019-10-01)
Tai, Ya-Hsiang
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Lin, Chi-Hao
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Yeh, Shan
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Tu, Cheng-Che
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Karim, Karim S.
In this article, we proposed a low-temperature poly-silicon (LTPS) active pixel sensor (APS) circuit with threshold voltage (V-th) compensation. LTPS thin-film transistors (TFTs) are known to degrade under long-term irradiation and this is quantified. Simulation results and experimental data confirm that the proposed APS circuit compensates the instability of LTPS TFTs and is a promising, high-performance alternative to current amorphous silicon (a-Si) pixel-based X-ray detectors.
Cyclic behavior of wide-flange steel braces with spliced mid-segment
(2019-10-01)
Chen, Chui-Hsin
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Ou, Chih-Chun
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Yu, Dong-Yin
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土木工程學系
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Department of Civil Engineering
RNN-Assisted Network Coding for Secure Heterogeneous Internet of Things With Unreliable Storage
(2019-10-01)
Liao, Chen-Hung
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Shuai, Hong-Han
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Wang, Li-Chun
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電機工程學系
;
Department of Electrical and Computer Engineering
With the rapid growth of Internet of Things (IoT), integrating a variety of IoT can result in novel applications. However, IoT devices are often deployed in an open environment where IoT are inclined to be malfunctioned. Although data reliability can be achieved by data recovery with conventional replication, the communication between IoT is susceptible to eavesdropping. Therefore, in this paper, we study the eavesdropping prevention of data repair in IoT environments based on network coding. We theoretically derive the relation between security level and storage in heterogeneous IoT systems. To further reduce the repair bandwidth, we exploit recurrent neural network for the storage failure prediction. Under the condition when failure probability and workloads of storage devices are considered, two allocation algorithms are proposed to avoid data repair. Finally, we show the relation between storage cost and reliability with different numbers of IoT devices. Experimental results manifest that the proposed allocation algorithms can outperform the baseline case by 18.4% in terms of the security level.
【產學合作】首創全光交換邊緣資料中心網路系統打造5G 時代必備基礎
(國立交通大學資訊學院, 2019-10)
田伯隆教授
國立交通大學資訊工程系楊啟瑞教授、電機工程系田伯隆教授與台達電子產學合作研發團隊獲邀參與三月在美國聖地牙哥及聖荷西舉行的光纖通訊博覽及研討會(IEEE/OSA Optical Fiber Conference，OFC) 及開放運算平台高峰會(Open Compute Project，OCP) ，發表全世界第一套結合智慧控制的「全光交換邊緣資料中心網路系統(OPTUNS)」。這項研發成果驚豔世界各大IT 廠，對此系統表達高度興趣與合作意願。
Nano-fibrous SrCe0.8Y0.2O3-delta-Ni anode functional layer for proton-conducting solid oxide fuel cells
(2019-10-01)
Lee, Kan-Rong
;
Tseng, Chung-Jen
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Chang, Jeng-Kuei
;
Wang, Kuan-Wen
;
Huang, Yu-Shuo
This study presents a nanofiber-derived functional anode consisting of proton-conducting SrCe0.8Y0.2O3-delta nanofibers and electro-catalytic Ni for proton-conducting solid oxide fuel cells. Fuel cell testing with the nano fibrous SrCe0.8Y0.2O3-delta-Ni anode exhibits a maximum power density of 201.0 mW/cm(2) at 800 degrees C, which is significantly higher than those of cells with a powder-derived Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-delta-Ni anode or a nano fibrous SrCe0.8Y0.2O3-delta anode. Its relatively lower ohmic resistance can be explained in terms of protonic and electronic "highways" throughout the nano-fibrous SrCe0.8Y0.2O3-delta-Ni anode. The significantly lower polarization resistance elements, R-1 and R-2, further indicate that the nano-fibrous SrCe0.8Y0.2O3-delta-Ni anode has superior catalytic activity for the hydrogen oxidation reaction and thus generates more protons that can participate in the cathode reactions. The results show that the performance enhancement in the fuel cell with the nano-fibrous SrCe0.8Y0.2O3-delta-Ni anode can be attributed to its low ohmic resistance, excellent electrode catalytic activity, and good gas transport property.
A Sustainable Soil Energy Harvesting System With Wide-Range Power-Tracking Architecture
(2019-10-01)
Ou, I-Che
;
Yang, Jia-Ping
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Liu, Chia-Hung
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Huang, Kai-Jie
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Tsai, Kun-Ju
For wide-range deployment of wireless sensing nodes in power- and size-constrained Internet of Things applications, self-sustaining wireless sensors without batteries are needed. The energy supply for these ubiquitous sensing devices should harness environmental energy sources to avoid frequent battery replacement and pollution. This paper presents a new soil energy harvesting system with a power management integrated circuit (IC) for wide-range maximum power point tracking (MPPT). The output power of a soil energy cell varies widely according to the soil moisture and soil contents. To extract the maximum amount of energy from the soil, high-efficiency power management with adaptive dc-dc conversion ratios and an MPPT mechanism is essential. The proposed system is implemented with a high-efficiency dc-dc converter IC in a 0.18-mu m CMOS process. The design achieves a peak tracking efficiency of 90.5% in the throughput power range from 56 mu W to 1 mW at an output voltage of 3 V and system efficiency exceeding 65% over an input resistance range of the soil energy source; the peak system efficiency is 73.9%. A demonstration was undertaken of the soil energy harvesting system lighting an LED array without any chemical batteries.
Experimental and Numerical Investigations on Jet Impingement Cooling for Electronic Modules
(2019-10-01)
Chu, Wen-Xiao
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Huang, Kuan-Chang
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Amer, Mohammed
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Wang, Chi-Chuan
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機械工程學系
In this paper, the influence of outlet arrangement and plenum structure on impingement cooling is experimentally and numerically investigated in a typical 1-U confined server space. Three outlets include Z-type, bilateral, and U-type arrangements, and the plenum configurations contain partially inclined, fully inclined, and staged layouts. As a result, using the U-type outlet or staged plenum may prominently compromise the impingement cooling performance on the target plates with lower pumping power. With numerical investigation, it is found that, for the case with Z-type outlet, the flowrate of jet impingement increases alongside the streamwise direction. Besides, the impingement stagnation region on target plates with the minimum thermal resistance may shift toward the outlet. Meanwhile, the uniformity of jet impingement can be improved by 10.7% and 50.3% when the bilateral and U-type outlets are applied, respectively, and the jet impingement is changed to perpendicular direction due to the opposite cross flow from the coming flow direction. On the other hand, by applying the inclined plenum and staged plenum, the uniformity of jet impingement can be dramatically improved by 113.9% and 215.1%, respectively. However, the local jet impingement velocity distribution is still nonuniform. Hence, a novel design of impingement plate based on the concept of Coanda effect is proposed. The peak value of the thermal resistance on target plate can be reduced by 21.8% and 16.0% at the center region and the fore part of the jet array.
廣義虛擬實境的發展軌跡與未來趨勢
(國立交通大學經營管理研究所, 2019-10-01)
盧煜煬
;
劉顯仲
;
謝志宏
;
陳淑娟
;
Louis Y. Y. Lu
本研究將虛擬實境（VR）、擴增實境（AR）與混合實境（MR）統稱為廣義的虛擬實境（the broad VR），從學術與專利資料庫中檢索相關文獻，進行過去發展軌跡的探索與未來研發趨勢之預測。由學術資料庫與專利資料庫中各獲得28,566及25,134篇文獻，針對學術文獻的引用資料建立引用網絡，再對引用網絡做主路徑分析，以得到總體發展軌跡，另做集群分析與文字雲分析獲得八大研究主題分別為：VR用於外科手術訓練、VR用於暴露治療、行動AR的應用、VR用於復健、VR用於產品開發、VR用於學習、AR用於手術導航以及VR用於腦部研究。接著，將兩種文獻中所有相關論文的名稱與摘要做文字探勘，找出出現頻率較高的關鍵詞，以了解研究者較有興趣的研究議題，並得知學術研究與專利研究的時間差為0到6年。最後，統計近四年學術研究的新興主題，以指引未來專利佈局的重點方向，此結果可供產官學界在擬定廣義虛擬實境未來發展方針之參考。本研究展示一個整合式的分析步驟，成功且有效地完成廣義VR技術發展與應用的軌跡，並預測未來專利研發的方向，為有興趣做科學發展文獻回顧與技術預測的研究者提供一個新的選擇。
A thermomagnetic-piezoelectric MEMS AC magnetic-field sensor demonstrating a novel room-temperature-range coil-less resetting/demagnetizing approach
(2019-10-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Tseng, Chia-Yung
;
Chung, Tien-Kan
We report a novel thermomagnetic-piezoelectric MEMS AC magnetic-field sensor. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) film covered by a Pt anti-oxidation layer. Due to the thermomagnetic-Gd/piezoelectric-PZT layered structure, the sensor not only can sense AC magnetic field, but also can be reset/demagnetized automatically at temperature higher than Gd's Curie temperature which is in room-temperature range. Experimental results show that the sensor successfully senses AC magnetic field from 1 to 14 Gauss at 9 degrees C, and is automatically reset/demagnetized at 45 degrees C. While conventional MEMS and AMR magnetic sensors using magnetic materials require on-chip resetting/demagnetizing coils which need a huge footprint of the chip, our sensor utilizing the coil-less resetting/demagnetizing approach significantly reduces the sensor footprint. In the other hand, when comparing to conventional coil-less resetting/demagnetizing method (i.e., annealing magnetic material at hundreds degrees C), our coil-less resetting/demagnetizing approach is at room-temperature range (for instant, 45 degrees C). (C) 2019 Elsevier B.V. All rights reserved.
Corporate governance and family succession: New evidence from Taiwan
(2019-10-01)
Yeh, Yin-Hua
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Succession in family firms has historically been associated with risk. However, improvements in laws and regulations along with the consequent improvements in corporate governance can greatly mitigate the potentially negative impacts on succession performance. This study utilizes a comprehensive data set of 280 cases of succession from Taiwan between the years 1997 and 2012, a period which coincides with the introduction of a big bang of new domestic laws and regulations. The results indicate that improvements in the regulatory environment along with the consequent strengthening of corporate governance reduces the probability of family succession while at the same time increases firm performance during the succession period. In many cases the impact of improved corporate governance outweighs the influence of improved laws and regulations. The implications of these findings underscore the importance of the government's role in establishing robust internal and external mechanisms to enhance corporate governance, so that in significant events such as firm succession, the attendant risks are reduced.
Optimization of InAs/GaSb core-shell nanowire structure for improved TFET performance
(2019-10-01)
Singh, Sankalp Kumar
;
Kakkerla, Ramesh Kumar
;
Joseph, H. Bijo
;
Gupta, Ankur
;
Anandan, Deepak
The performance of InAs/GaSb core-shell nanowire TFET is systematically investigated for the effects of intrinsic device parameters such as channel doping, shell thickness, spacer length and source offset. Device ON-current (I-ON) was chosen as the key figure of merit. It is found that I-ON improves due to improved electrostatic control achieved by the TFET with optimum shell diameter. The maximum I-ON obtained for a shell thickness of 2 nm was 33.65 mu A/mu m and a Subthreshold Swing (SS) of 12.9 mV/decade with an I-ON/I-OFF ratio of 1.49 x 10(8) for our device. Device I-ON can be further improved by adding an optimum spacer at the source-channel junction. It was also found that device ON-current is almost constant and does not get much affected by having a larger shell offset.