Browsing by Issue Date, starting with "2014-07-03"

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Non-conventional three-armed star-shaped mesogens based on 1,3,5-trisubstituted benzene with azobenzene moieties at the periphery: synthesis, and mesomorphic behaviour
(2014-07-03)
Ooi, Yew-Hong
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Yeap, Guan-Yeow
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Han, Chun-Chieh
;
Lin, Hong-Cheu
;
Shinomiya, Teruo
A series of new symmetrical trimeric star-shaped mesogens in which the molecular architecture composed of three 4-[(4-substituted-phenyl)diazenyl]phenoxy-6-bromohexane connected as the pheripheral units to 1,3,5-positions of the benzene core group have been synthesised and fully characterised by physical measurements and spectroscopic techniques (carbon, hydrogen and nitrogen microanalysis, Fourier transform-infrared spectroscopy and nuclear magnetic resonance: CHN, FT-IR and NMR). At one end of the para-position of the azobenzene fragment consists of different terminal substituents X=F, Cl, Br, I, C2H5 and OC2H5. The thermal behaviour and mesomorphic properties of the star-shaped compounds were investigated by means of differential scanning calorimetry, polarizing optical microscopy (POM) and X-ray diffraction analyses. Moreover, the liquid-crystalline properties of all the intermediates 4-[(4-substituted-phenyl)diazenyl]phenoxy-6-bromohexane were also evaluated. Whilst all the star-shaped compounds exhibit nematic and smectic A phases, the mesogens with chloro- and bromo-terminal substituents were found to show soft crystalline phase. The smectic phase and the possible molecular arrangement of the star-shaped molecule within the anisotropic region were further substantiated by the XRD. In addition to a low-angle sharp peak (reflecting the layered structure), a diffuse wide-angle peak indicating the liquid-like order within the smectic layer was recorded. A comparative study between the properties of the present azo mesogens and the earlier reported star-shaped mesogens from Schiff bases is also discussed.
InAs-based heterostructure field-effect transistor using AlAs0.16Sb0.84 double barriers
(2014-07-03)
Lin, Yue-Min
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Lin, Kun-Ping
;
Lee, Ting-Chi
;
Li, Meng-Ying
;
Lee, Chien-Ping
An InAs-channel heterostructure field-effect transistor on GaAs substrates is presented. The conduction channel was formed by the InAs/AlAs0.16Sb0.84/AlSb quantum well. With the addition of the AlAs0.16Sb0.84 layer, holes that are generated by impact ionisation at high voltages are effectively confined in the InAs channel because of the large Delta Ev in this type-I heterostructure. By suppressing the hole injection into and accumulation in the buffer layer, the feedback through the back gate is eliminated and excellent output characteristics were obtained. The fabricated devices had a threshold voltage of about -0.6 V with a channel mobility of 18 100 cm(2)/V-s and a sheet carrier density of 1.2 x 10(12) cm(-2).
Editorial introduction: Chen Yingzhen and his time
(2014-07-03)
Chen, Kuan-Hsing
;
社會與文化所
;
Institute of Social Research and Culture Studies
PRESSURE AND SHEAR FORCE MEASUREMENT DEVICE AND METHOD
(2014-07-03)
Huang Cheng-Sheng
;
Yang Bing-Shiang
;
Jang Wen-Yea
A pressure and shear force measurement device and a pressure and shear force measurement method are disclosed. The measurement device includes a flexible substrate; a plurality of signal outputting units embedded in the flexible substrate for outputting signals; and a plurality of signal detectors disposed at a peripheral of the flexible substrate for receiving at least a signal outputted from the signal outputting units, wherein when the flexible substrate has a load applied thereon and each of the signal outputting units has a displacement, each of the signal detectors detects a pressure and a shear force resulting from the load on the flexible substrate based on the signal received from the signal outputting units.
Revisiting dual-role factors in data envelopment analysis: derivation and implications
(2014-07-03)
Chen, Wen-Chih
;
工業工程與管理學系
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Department of Industrial Engineering and Management
Data Envelopment Analysis (DEA) is a mathematical programming method to evaluate relative performance. Typical DEA studies consider a production process transforming inputs to outputs. In some cases, however, some factors can be both inputs and outputs simultaneously and are termed dual-role factors. For example, research funding can be an input that strengthens a university's academic performance and the actual funds can be an output. This article investigates the problem of how to incorporate dual-role factors in DEA. Rather than proposing an ad hoc evaluation model directly, this article considers the concept of "joint technology," two individual production processes acting in common by summarizing the intuitive thinking. The efficiency evaluation models, based on variant assumptions, thus can be axiomatically derived, validated, and extended. How to determine the input/output tendency of a dual-role factor based on the evaluating results is shown and explained from different aspects. It is concluded that the tendency is a property on the projected boundary, not the data point itself.
InAs-based heterostructure field-effect transistor using AlAs0.16Sb0.84 double barriers
(2014-07-03)
Lin, Yue-Min
;
Lin, Kun-Ping
;
Lee, Ting-Chi
;
Li, Meng-Ying
;
Lee, Chien-Ping
An InAs-channel heterostructure field-effect transistor on GaAs substrates is presented. The conduction channel was formed by the InAs/AlAs0.16Sb0.84/AlSb quantum well. With the addition of the AlAs0.16Sb0.84 layer, holes that are generated by impact ionisation at high voltages are effectively confined in the InAs channel because of the large Delta Ev in this type-I heterostructure. By suppressing the hole injection into and accumulation in the buffer layer, the feedback through the back gate is eliminated and excellent output characteristics were obtained. The fabricated devices had a threshold voltage of about -0.6 V with a channel mobility of 18 100 cm(2)/V-s and a sheet carrier density of 1.2 x 10(12) cm(-2).
FALL DETECTION AND PROTECTION SYSTEM AND METHOD
(2014-07-03)
Yang Bing-Shiang
;
Lin Cheng-Wei
The invention provides a fall detection and protection system and method. The fall detection and protection system includes a guarding device to be worn on a user, and a portable device having a pre-determined threshold value stored therein for detecting an activity of a user to acquire an activity status value, which is to be compared with the threshold value so as to detect and determine whether the user falls. When a fall is detected, the portable device transmits a triggering signal to the guarding device to activate the guarding function of the guarding device, thereby preventing the user from injury caused by the impact and collision of a fall.
ROTATION TYPE OPTICAL TOMOGRAPHY SCANNER
(2014-07-03)
Fang Wai-Chi
;
Chen Tien-Ho
;
Kang Shih
;
Wu Shih-Yang
;
Cheng Ching-Ju
A rotation type optical tomography scanner is provided, including an illuminating unit disposed on a surface of an object-to-be-detected for emitting incident light to tissues under the surface of the object-to-be-detected; a detecting unit disposed on the object-to-be-detected and rotating around the illuminating unit to receive diffuse light diffused from the tissues under the surface of the object-to-be-detected and generate tissue sensing information; and a positioning unit for generating position information of the rotation type optical tomography scanner. The rotation type optical tomography scanner transmits the sensing information and the position information to a remodel module to rebuild the tissue images under the surface of the object-to-be-detected, thereby expanding the scanning range of the object-to-be-detected.
Efficiency enhancement of non-selenized Cu(In,Ga)Se-2 solar cells employing scalable low-cost antireflective coating
(2014-07-04)
Jheng, Bao-Tang
;
Liu, Po-Tsun
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Wu, Meng-Chyi
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光電工程學系
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顯示科技研究所
In this study, a non-selenized CuInGaSe2 (CIGS) solar device with textured zinc oxide (ZnO) antireflection coatings was studied. The ZnO nanostructure was fabricated by a low-temperature aqueous solution deposition method. With controlling the morphology of the solution-grown tapered ZnO nanorod coatings, the average reflectance of the CIGS solar device decreased from 8.6% to 2.1%, and the energy conversion efficiency increased from 9.1% to 11.1%. The performance improvement in the CuInGaSe2 thin-film solar cell was well explained due to the gradual increase of the refractive index between air and the top electrode of solar cell device by the insertion of the ZnO nanostructure. The results demonstrate a potential application of the ZnO nanostructure array for efficient solar device technology.
Surveillance on-the-road: Vehicular tracking and reporting by V2V communications
(2014-07-04)
Chen, Lien-Wu
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Tseng, Yu-Chee
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Syue, Kun-Ze
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資訊工程學系
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Department of Computer Science
Vehicular networks have attracted a lot of attention recently. One potential application of vehicular networks is to use video cameras embedded in vehicles to support video surveillance, which we call "surveillance on-the-road". Traditional surveillance systems only rely on fixed stations on the roads to monitor road conditions. With vehicular cameras, deeper and richer road conditions may be tracked. In this paper, we study the related communication issues to support such "on-the-road" surveillance scenarios. We use monitoring and tracking suspicious vehicles (such as stolen cars) on the road through license plate recognition (LPR) as an example (our results should be applicable to other scenarios as well). We show how vehicles can work cooperatively through vehicle-to-vehicle (V2V) communications to achieve this goal. With a tracking and a reporting modules, our solution does not rely on infrastructure networks. The tracking module allows handoff of a tracking job to neighboring vehicles as necessary and report of suspicious vehicles to nearby police cars. The reporting module can help guide message flows to avoid flooding the network. Simulation results verify the message efficiency of our approach. We also show how our framework can be applied to the developing WAVE/DSRC (Wireless Access in Vehicular Environments/Dedicated Short Range Communications) standards. (C) 2014 Elsevier B.V. All rights reserved.
Efficiency improvement of InGaP/GaAs/Ge solar cells by hydrothermal-deposited ZnO nanotube structure
(2014-07-05)
Chung, Chen-Chen
;
Binh Tinh Tran
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Lin, Kung-Liang
;
Ho, Yen-Teng
;
Yu, Hung-Wei
In this paper, a zinc oxide (ZnO) nanotube, fabricated by the hydrothermal growth method on triple-junction (T-J) solar cell devices to enhance efficiency, is investigated. Compared to those of bare T-J solar cells (without antireflection (AR) coating) and solar cells with Si3N4 AR coatings, the experimental results show that the T-J solar cells, which use a ZnO nanotube as an AR coating, have the lowest reflectance in the short wavelength spectrum. The ZnO nanotube has the lowest light reflection among all experimental samples, especially in the range of 350 to 500 nm from ultraviolet (UV) to visible light. It was found that a ZnO nanotube can enhance the conversion efficiency by 4.9%, compared with a conventional T-J solar cell. The Si3N4 AR coatings also enhance the conversion efficiency by 3.2%.The results show that a cell with ZnO nanotube coating could greatly improve solar cell performances.
中正大社區客家藝文饗宴
(2014-07-06)
Department of Communication and Technology
;
傳播與科技學系
社區總體營造，一個為了建立社區文化、凝聚社區共識而形成的政策性名詞，近幾年來盛行於台灣大街小巷的各個社區中。其中，桃園縣龍潭鄉中正社區也不例外。然而，最獨特的在於，這裡是桃園最大的客家社區。
Insulating state to quantum Hall-like state transition in a spin-orbit-coupled two-dimensional electron system
(2014-07-07)
Lo, Shun-Tsung
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Hsu, Chang-Shun
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Lin, Y. M.
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Lin, S-D
;
Lee, C. P.
We study interference and interactions in an InAs/InAsSb two-dimensional electron system. In such a system, spin-orbit interactions are shown to be strong, which result in weak antilocalization (WAL) and thereby positive magnetoresistance around zero magnetic field. After suppressing WAL by the magnetic field, we demonstrate that classical positive magnetoresistance due to spin-orbit coupling plays a role. With further increasing the magnetic field, the system undergoes a direct insulator-quantum Hall transition. By analyzing the magnetotransport behavior in different field regions, we show that both electron-electron interactions and spin-related effects are essential in understanding the observed direct transition. (C) 2014 AIP Publishing LLC.
Recombination dynamics of a localized exciton bound at basal stacking faults within the m-(p)lane ZnO film
(2014-07-07)
Yang, S.
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Hsu, H. C.
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Liu, W-R.
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Lin, B. H.
;
Kuo, C. C.
We investigated the carrier dynamics near basal stacking faults (BSFs) in m-plane ZnO epitaxial film. The behaviors of the type-II quantum wells related to the BSFs are verified through time-resolved and time-integrated photoluminescence. The decay time of the emission of BSFs is observed to have a higher power law value and longer decay time than the emission of the donor-bound excitons. The spectral-dependent decay times reveal a phenomenon of carriers migrating among band tail states, which are related to the spatial distribution of the type-II quantum wells formed by the BSFs. A high density of excited carriers leads to a band bending effect, which in turn causes a blue-shift of the emission peak of BSFs with a broadened distribution of band tail states. (C) 2014 AIP Publishing LLC.
High performance 380-nm ultraviolet light-emitting-diodes with 3% efficiency droop by using free-standing GaN substrate manufacturing from GaAs substrate
(2014-07-07)
Shieh, Chen-Yu
;
Tsai, Ming-Ta
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Li, Zhen-Yu
;
Kuo, Hao-Chung
;
Chang, Jeng-Yang
We investigated the influence of free-standing GaN (FS-GaN) substrates on the performance of ultraviolet light-emitting-diodes (UV-LEDs) grown on top by atmospheric pressure metal-organic chemical vapor deposition. High-resolution double-crystal x-ray diffraction (HRDCXD) analysis demonstrated high-order satellite peaks and clear fringes between them for UV-LEDs grown on the FS-GaN substrate, from which the interface roughness was estimated. In addition, the full width at half maximum of the HRDCXD rocking curve in the (0002) and the (1012) reflections were reduced to below 90 arc sec. The Raman results indicated that the GaN-based epilayer of strain free was grown. Additionally, the effect of the FS-GaN substrate on the crystal quality of the UV-LEDs was examined in detail by transmission electron microscopy (TEM). The TEM characterizations revealed no defects and V-pits were found in the scanned area. Based on the results mentioned above, the light output power of UV-LEDs on the FS-GaN substrate can be enhanced drastically by 80% and 90% at 20 and 100 mA, respectively. Furthermore, an ultralow efficiency degradation of about 3% can be obtained for the UV-LEDs on the FS-GaN substrate at a high injection current. The use of an FS-GaN substrate is suggested to be effective for improving the emission efficiency and droop of UV-LEDs grown thereon.
交大e-News第166期
(2014-07-07)
Secretariat
;
國立交通大學秘書室
Method of implementing timing engineering change order
(2014-07-08)
Chang Hua-Yu
;
Jiang Hui-Ru
;
Chang Yao-Wen
A method of implementing timing ECO in a circuit includes the steps of performing a static timing analysis on the circuit so as to determine at least one timing violating path of the circuit, decomposing the timing violating path into at least one violating path segment, determining a smooth curve from each timing violating path and determining a plurality of reference points along the smooth curve, computing a fixability parameter of each gate on the violating path segment, extracting at least one gate according to the fixability parameters, and selecting one spare cell and disposing the selected spare cell on the violating path segment.
Liquid dielectrophoretic device and method for controllably transporting a liquid using the same
(2014-07-08)
Fan Shih-Kang
;
Lu I-Pei
A liquid dielectrophoretic device comprises: a first container unit defining a first micro containing space including an electrode pair for generating a dielectrophoretic force; a second container unit defining a second micro containing space and including an electrode pair for generating a dielectrophoretic force; and a fluid channel unit defining a micro-channel between the first and second micro containing spaces and including an electrode pair having a middle region layer that has first and second enlarged sections and a middle section disposed between the first and second enlarged sections. The first and second enlarged sections are enlarged gradually from the middle section to the first and second micro containing spaces. A method for controllably transporting a liquid using the liquid dielectrophoretic device is also disclosed.
Static random access memory with ripple bit lines/search lines for improving current leakage/variation tolerance and density/performance
(2014-07-08)
Chuang Ching-Te
;
Yang Hao-I
;
Lu Chien-Yu
;
Chen Chien-Hen
;
Chang Chi-Shin
A static random access memory includes a pre-charger, a first cell column array/peripheral circuit, and a first ripple buffer. The pre-charger is connected to a first local bit line in order to pre-charge the first local bit line. The first cell column array/peripheral circuit is connected to the first local bit line and has a plurality of cells for temporarily storing data. The cells are connected to the first local bit line. The first ripple buffer is connected to the first local bit line and a second local bit line in order to send the data from the first local bit line to the second local bit line.
Band Gap-Tunable Molybdenum Sulfide Selenide Monolayer Alloy
(2014-07-09)
Su, Sheng-Han
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Hsu, Yu-Te
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Chang, Yung-Huang
;
Chiu, Ming-Hui
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Hsu, Chang-Lung