Browsing by Issue Date, starting with "2017-02-05"

Now showing 1 - 20 of 14462

On cold-aisle containment of a container datacenter
(2017-02-05)
Wang, Cheng-Hao
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Tsui, Yeng-Yung
;
Wang, Chi-Chuan
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機械工程學系
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Department of Mechanical Engineering
In this study, influences of various blockage arrangements as well as cold-aisle containment on the overall efficiency of a container datacenter are reported. The test container datacenter contains ten racks and the cold air is supplied from drop ceiling. The experiments are performed with each rack equally delivering a power of 3 kW. Eight different layouts are examined. Appreciable hot air recirculation prevails especially at the entrance of cold aisle. Adding blockage plates to the computer room air handler (CRAH) at the entrance of computer racks only improve marginally the associated rack cooling index (RCI). Layout with enclosing the end of cold aisle while let open the entrance of cold aisle also performs poorly. Full containment of the cold aisle with high jet air flowrate from the supplied grilles gives the worst performance. Layout with enclosing at the entrance of cold aisle but let open the end of cold aisle shows a much superior temperature distribution and a rather high RCI of 99%. Higher supplied flow may induce jet airflow pattern, causing the Coanda effect to result in fluctuating behaviors of RCI and SHI alongside the cold aisle (zigzag phenomenon). A lower supplied air flowrate without Coanda effect for a full containment design give the best overall performance. (C) 2016 Elsevier Ltd. All rights reserved.
Analytical analysis and experimental verification of interleaved parallelogram heat sink
(2017-02-05)
Chen, Hong-Long
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Wang, Chi-Chuan
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機械工程學系
;
Department of Mechanical Engineering
In this study, a novel air-cooled heat sink profile is proposed to compete with the conventional design. The new design is termed as IPFM (Interleaved Parallelogram Fin Module) which features two different geometrical perimeter shapes of fins. This new design not only gains the advantage of lower pressure drop for power saving; but also gains a material saving for less fin surface area. An assessment of flow impedance and performance between the conventional and IPFM heat sink is analytically investigated and experimentally verified. A new modified dimensionless friction factor for triangular region is proposed. The analytical predictions agree with experimental measurements for both conventional and IPFM design. In electronic cooling design, especially for cloud server air-cooled heat sink design, the flow pattern is usually laminar with Reynolds number being operated less than 2000. In this regime, the IPFM design shows 8-12% less of surface than conventional design when the flow rate is less than 10 CFM; yet the thermal performance is slightly inferior to the conventional design when the flowrate is raised towards 25 CFM. Yet in the test range of 5-25 CFM, a 10-15% lower flow impedance is observed. The smaller fin spacing, the more conspicuous reduction of flow impedance is observed. The optimization of cutting angle is around 35 degrees for 10 CFM, and it is reduced to 15 degrees at a larger flowrate of 20 CFM. (C) 2016 Elsevier Ltd. All rights reserved.
Using nanoindentation and cathodoluminescence to identify the bundled effect of gallium nitride grown by PA-MBE
(2017-02-05)
Wen, Hua-Chiang
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Chou, Wu-Ching
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Chiang, Tun-Yuan
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Jeng, Yeau-Ren
;
Fan, Wen-Chung
We performed cathodoluminescence (CL) investigations on GaN NCs grown using molecular beam epitaxy. Bundled GaN was used to form NCs that were deposited onto commercial sapphire templates. The structures of the bundled NCs were analyzed using nanoindentation. The samples were grown with a T-G of 700, 800, and 850 degrees C, and the H values were 7.4 +/- 0.2 and 6.4 +/- 0.2 GPa; the E values were 308.4 +/- 4.3, 296.4 +/- 3.8, and 75.5 +/- 1.4 GPa, respectively. It is suspected that the discrepancies of the mechanical parameters obtained by various indentation methods are partially a result of the stress distribution inherent in the different orientations on the sapphire substrate. A scanning electron microscopy (SEM) system equipped with CL allows the direct comparison of SEM images and CL maps, captured from exactly the same area of the samples. In addition to the SEM and CL images, photoluminescence spectroscopy (PL) profiling was obtained by collecting the 20 K PL spectra at the samples. The PL profiling enables the distinguishing of the emissions by the 5 meV of the blueshift from 3.440 to 3.445 eV due to localization effects. The bundled GaN NCs resulted from the (0002) reflection at 34.6 degrees for a wurtzite structure and a raised intensity difference when the TG was increased from 700 to 850 degrees C. The crystal texture of the GaN can influence the mechanical properties at different TG stages. (C) 2016 Elsevier B.V. All rights reserved.
The Spatiotemporal Control of Osteoblast Cell Growth, Behavior, and Function Dictated by Nanostructured Stainless Steel Artificial Microenvironments
(2017-02-06)
Dhawan, Udesh
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Pan, Hsu-An
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Shie, Meng-Je
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Chu, Ying Hao
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Huang, Guewha S.
The successful application of a nanostructured biomaterial as an implant is strongly determined by the nanotopography size triggering the ideal cell response. Here, nanoporous topography on 304L stainless steel substrates was engineered to identify the nanotopography size causing a transition in the cellular characteristics, and accordingly, the design of nanostructured stainless steel surface as orthopedic implants is proposed. A variety of nanopore diameters ranging from 100 to 220 nm were fabricated by one-step electrolysis process and collectively referred to as artificial microenvironments. Control over the nanopore diameter was achieved by varying bias voltage. MG63 osteoblasts were cultured on the nanoporous surfaces for different days. Immunofluorescence (IF) and scanning electron microscopy (SEM) were performed to compare the modulation in cell morphologies and characteristics. Osteoblasts displayed differential growth parameters and distinct transition in cell behavior after nanopore reached a certain diameter. Nanopores with 100-nm diameter promoted cell growth, focal adhesions, cell area, viability, vinculin-stained area, calcium mineralization, and alkaline phosphatase activity. The ability of these nanoporous substrates to differentially modulate the cell behavior and assist in identifying the transition step will be beneficial to biomedical engineers to develop superior implant geometries, triggering an ideal cell response at the cell-nanotopography interface.
Modelling end-pumped passively Q-switched Nd-doped crystal lasers: manifestation by a Nd:YVO4/Cr4+:YAG system with a concave-convex resonator
(2017-02-06)
Tuan, P. H.
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Chang, C. C.
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Chang, F. L.
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Lee, C. Y.
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Sung, C. L.
A theoretical model for the passively Q-switched (PQS) operation which includes the spatial overlapping between the pump and lasing modes under the thermal lensing effect is developed to give a transcendental equation that can directly determine the critical parameters such as pulse energy, pulse repetition rate, and pulse width for the PQS performance. More importantly, an analytical function which gives the approximate solution for the transcendental equation as well as a specific critical criterion for good PQS operation are derived for practical analyses and design. A Nd: YVO4/Cr4+: YAG system with a concave-convex resonator which can achieve fairly stable PQS pulse trains even at a high pump level is further exploited to manifest the proposed spatially dependent model. The good agreement between the experimental results and the theoretical predictions is verified to show the feasibility of the proposed model for designing high-power PQS lasers with high accuracy. (C) 2017 Optical Society of America
Photo-switchable chiral liquid crystal with optical tristability enabled by a photoresponsive azo-chiral dopant
(2017-02-06)
Hsiao, Yu-Cheng
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Huang, Kuan-Chung
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Lee, Wei
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光電系統研究所
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影像與生醫光電研究所
A light-driven tristable chiral-tilted homeotropic nematic (TCHN) cell is demonstrated. The liquid-crystal cell is photo-switchable among the three stable states: the tilted-homeotropic, fingerprint, and the tilted-twist states. The inclusion of a photosensitive chiral bis(azobenzene) compound into a typical nematic liquid crystal makes the resulting material possible to switch from one to another stable state directly and reversibly owing to the photoinduced trans-cis isomerization of the azo-chiral dopant and, hence, the configurational change of the liquid crystal via the guest-host effect. By further introducing dichroic dyes into the TCHN system, we devised a polarizer-free display and light modulators. The novel TCHN composite material opens up new possible applications in lightdriven optical elements and devices. (C) 2017 Optical Society of America.
Inverse magnetic catalysis in the soft-wall model of AdS/QCD
(2017-02-07)
Li, Danning
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Huang, Mei
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Yang, Yi
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Yuan, Pei-Hung
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電子物理學系
Magnetic effects on chiral phase transition have been investigated in a modified soft-wall AdS/QCD model, in which the dilaton field is taken to be negative at the ultraviolet region and positive at the infrared region as in Phys. Rev. D 93 (2016) 101901 and JHEP 04 (2016) 036. The magnetic field is introduced into the background geometry by solving the Einstein-Maxwell system. After embedding the magnetized background geometry into the modified soft-wall model, the magnetic field dependent behavior of chiral condensate is worked out numerically. It is found that, in the chiral limit, the chiral phase transition remains as a second order at finite magnetic field B, while the symmetry restoration temperature and chiral condensate decrease with the increasing of magnetic field in small B region. When including finite quark mass effect, the phase transition turns to be a crossover one, and the transition temperature still decreases with increasing magnetic field B when B is not very large. In this sense, inverse magnetic catalysis effect is observed in this modified soft-wall AdS/QCD model.
All-electric spin pumping in quantum channels with a single finger-gate capacitor
(2017-02-07)
Wang, L. Y.
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Chu, C. S.
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電子物理學系
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Department of Electrophysics
In this paper, we show that a single finger-gate capacitor (FGC) can generate pure spin pumping in a quantum channel (QC). Two dynamic fields, ac spin-orbit interaction and ac potential energy, both induced by the FGC onto the QC, are the agents driving the spin pumping. Smooth spatial profiles of the two ac fields are taken into account both perturbatively and full numerically for the nonadiabatic spin pumping. Our perturbative approach reveals that the spin-pumping mechanism is resonant sideband processes associated with simultaneous coupling of the two ac fields with traversing carriers. Full sideband-process treatment is carried out numerically by a time-dependent scattering matrix method. The same spin-pumping mechanism holds also for the case of a single finger-gated QC, albeit with smaller pumping amplitudes.
Size-Dependent Optical Properties of Grana Inside Chloroplast of Plant Cells
(2017-02-09)
Uwada, Takayuki
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Huang, Ling-Ting
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Hee, Ping-Yu
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Usman, Anwar
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Masuhara, Hiroshi
Well-packed thylakoids known as grana are one of the major functional sites for photosynthesis in algae and plants. Their highly ordered structures can be considered as a few hundred nanometer-sized particles having distinct scattering cross sections from other various macromolecular organizations inside plant cells. With this background we shOw that elastic light scattering imaging and microspectroscopy is an important tool for investigating structure and organisation of grana inside a single chloroplast in plant tells. We have demonstrated this noninvasive method to identify the distribution of grana in intact fresh leaf of robust and rapidly growing Egaria densa, which is also known as Anachris and among the most popular aquarium plants. The scattering efficiency spectra of their individual grana fairly resemble cooperative absorption spectra of porphyrins and carotenoids. We found that the electronic structure of the stacked thylakoids shows granum size-dependence, indicating that size of grana is one of the critical parameters in the regulation of the photochemical functions in the thylakoid.
USE OF KNOWN COMPOUNDS AS D-AMINO ACID OXIDASE INHIBITORS
(2017-02-09)
Yufeng Jane TSENG
;
Yu-Li LIU
;
Chung-Ming SUN
;
Hai-Gwo HWU
;
Chih-Min LIU
The invention utilizes virtual screening strategy to seek for current market drugs as anti-schizophrenia therapy drug repurposing. Drug repurposing strategy finds new uses other than the original medical indications of existing drugs. Finding new indications for such drugs will benefit patients who are in needs for a potential new therapy sooner since known drugs are usually with acceptable safety and pharmacokinetic profiles. In this study, repurposing marketed drugs for DAAO inhibitor as new schizophrenia therapy was performed with virtual screening on marketed drugs and its metabolites. The identified and available drugs and compounds were further confirmed with in vitro DAAO enzymatic inhibitory assay.
Comprehensive target capture/next-generation sequencing as a second-tier diagnostic approach for congenital muscular dystrophy in Taiwan
(2017-02-09)
Liang, Wen-Chen
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Tian, Xia
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Yuo, Chung-Yee
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Chen, Wan-Zi
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Kan, Tsu-Min
Purpose Congenital muscular dystrophy (CMD) is a heterogeneous disease entity. The detailed clinical manifestation and causative gene for each subgroup of CMD are quite variable. This study aims to analyze the phenotypes and genotypes of Taiwanese patients with CMD as the epidemiology of CMD varies among populations and has been scantly described in Asia. Methods A total of 48 patients suspected to have CMD were screened and categorized by histochemistry and immunohistochemistry studies. Different genetic analyses, including next-generation sequencing (NGS), were selected, based on the clinical and pathological findings. Results We identified 17 patients with sarcolemma-specific collagen VI deficiency (SSCD), 6 patients with merosin deficiency, two with reduced alpha-dystroglycan staining, and two with striking lymphocyte infiltration in addition to dystrophic change on muscle pathology. Fourteen in 15 patients with SSCD, were shown to have COL6A1, COL6A2 or COL6A3 mutations by NGS analysis; all showed marked distal hyperlaxity and normal intelligence but the overall severity was less than in previously reported patients from other populations. All six patients with merosin deficiency had mutations in LAMA2. They showed relatively uniform phenotype that were compatible with previous studies, except for higher proportion of mental retardation with epilepsy. With reduced alpha-dystroglycan staining, one patient was found to carry mutations in POMT1 while another patient carried mutations in TRAPPC11. LMNA mutations were found in the two patients with inflammatory change on muscle pathology. They were clinically characterized by neck flexion limitation and early joint contracture, but no cardiac problem had developed yet. Conclusion Muscle pathology remains helpful in guiding further molecular analyses by direct sequencing of certain genes or by target capture/NGS as a second-tier diagnostic tool, and is crucial for establishing the genotype-phenotype correlation. We also determined the frequencies of the different types of CMD in our cohort which is important for the development of a specific care system for each disease.
PACKAGE STRUCTURE OF A LIGHT-EMITTING DEVICE
(2017-02-09)
Chien-Chung Lin
;
Hao-Chung Kuo
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Chin-Wei Sher
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Hau-Vei Han
;
Kuo-Ju Chen
A light-emitting device packaging structure is provided. The light-emitting device packaging structure includes a substrate, an array of light-emitting devices, an encapsulating layer, scattering particles, and a fluorescent material layer. The array of light-emitting devices is on the substrate. The encapsulating layer covers the array of light-emitting devices. The scattering particles are dispersed in the encapsulating layer. The fluorescent material layer is on the encapsulating layer.
PHOTODETECTING DEVICE AND METHOD OF USING THE SAME
(2017-02-09)
Yuh-Shyong YANG
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Chien-Hung CHEN
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Chih-Heng LIN
A photodetecting device and method of using the same are provided. The photodetecting device includes a transistor, a silicon nano-channel and a filter dye layer. The transistor includes a source, a drain and a gate. The silicon nano-channel connects the source and the drain, and is configured to receive light. The filter dye layer is over a light-receiving surface of the silicon nano-channel.
薬物組成物およびその製造方法
(2017-02-09)
黄唯▲ティン▼
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李翊綺
;
劉典謨
【課題】薬物組成物およびその製造方法を提供する。【解決手段】複数の親水基と複数の疎水基で変性された両親媒性キトサン誘導体と、前記両親媒性キトサン誘導体に埋め込められ、静電力により前記複数の親水基を吸引する少なくとも一つの親水性薬物と、前記両親媒性キトサン誘導体に埋め込められ、前記複数の疎水基の間にある少なくとも一つの疎水性薬物と、を含む、薬物組成物を提供する。また、複数の親水基と複数の疎水基で変性された両親媒性キトサン誘導体と、少なくとも一つの疎水性薬物と、少なくとも一つの親水性薬物とを溶剤に分散させて混合溶液を形成し、前記混合溶液のｐＨを前記親水性薬物および前記疎水性薬物が沈殿しない範囲に調整することと、前記混合溶液を少なくとも１２時間撹拌し、前記混合溶液のｐＨを６〜７にすることと、を含む薬物組成物の製造方法を提供する。【選択図】図１
In-situ Multimodal Imaging and Spectroscopy of Mg Electrodeposition at Electrode-Electrolyte Interfaces
(2017-02-10)
Wu, Yimin A.
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Yin, Zuwei
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Farmand, Maryam
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Yu, Young-Sang
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Shapiro, David A.
We report the study of Mg cathodic electrochemical deposition on Ti and Au electrode using a multimodal approach by examining the sample area in-situ using liquid cell transmission electron microscopy (TEM), scanning transmission X-ray microscopy (STXM) and X-ray absorption spectroscopy (XAS). Magnesium Aluminum Chloride Complex was synthesized and utilized as electrolyte, where non-reversible features during in situ charging-discharging cycles were observed. During charging, a uniform Mg film was deposited on the electrode, which is consistent with the intrinsic non-dendritic nature of Mg deposition in Mg ion batteries. The Mg thin film was not dissolvable during the following discharge process. We found that such Mg thin film is hexacoordinated Mg compounds by in-situ STXM and XAS. This study provides insights on the non-reversibility issue and failure mechanism of Mg ion batteries. Also, our method provides a novel generic method to understand the in situ battery chemistry without any further sample processing, which can preserve the original nature of battery materials or electrodeposited materials. This multimodal in situ imaging and spectroscopy provides many opportunities to attack complex problems that span orders of magnitude in length and time scale, which can be applied to a broad range of the energy storage systems.
Contrast-sensitivity-based evaluation method of a surveillance camera's visual resolution: improvement from the conventional slanted-edge spatial frequency response method
(2017-02-10)
Qin, Zong
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Wong, Po-Jung
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Chao, Wei-Chung
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Lin, Fang-Cheng
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Huang, Yi-Pai
Visual resolution is an important specification of a surveillance camera, and it is usually quantified by linewidths per picture height (LW/PH). The conventional evaluation method adopts the slanted-edge spatial frequency response (e-SFR) and uses a fixed decision contrast ratio to determine LW/PH. However, this method brings about a considerable error with respect to subjectively judged results because the perceptibility of the human vision system (HVS) varies with spatial frequency. Therefore, in this paper, a systematic calculation method, which combines the contrast sensitivity function characterizing the HVS and e-SFR, is proposed to solve LW/PH. Eight 720P camera modules in day mode, four 720P modules in night mode, and two 1080P modules in day mode are actually adopted. Corresponding to the three modes, mean absolute error between objective and subjective LW/PH are suppressed to as low as 26 (3.6% of 720P), 27 (3.8% of 720P), and 49 (4.5% of 1080P), while those of the conventional method are 68 (9.4% of 720P), 95 (13.2% of 720P), and 118 (10.9% of 1080P).(C) 2017 Optical Society of America
A Novel Read Scheme for Large Size One-Resistor Resistive Random Access Memory Array
(2017-02-10)
Zackriya, Mohammed, V
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Kittur, Harish M.
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Chin, Albert
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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
The major issue of RRAM is the uneven sneak path that limits the array size. For the first time record large One-Resistor (1R) RRAM array of 128x128 is realized, and the array cells at the worst case still have good Low-/High-Resistive State (LRS/HRS) current difference of 378 nA/16 nA, even without using the selector device. This array has extremely low read current of 9.7 mu A due to both low-current RRAM device and circuit interaction, where a novel and simple scheme of a reference point by half selected cell and a differential amplifier (DA) were implemented in the circuit design.
Ran-dependent TPX2 activation promotes acentrosomal microtubule nucleation in neurons
(2017-02-13)
Chen, Wen-Shin
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Chen, Yi-Ju
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Huang, Yung-An
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Hsieh, Bing-Yuan
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Chiu, Ho-Chieh
The microtubule (MT) cytoskeleton is essential for the formation of morphologically appropriate neurons. The existence of the acentrosomal MT organizing center in neurons has been proposed but its identity remained elusive. Here we provide evidence showing that TPX2 is an important component of this acentrosomal MT organizing center. First, neurite elongation is compromised in TPX2-depleted neurons. In addition, TPX2 localizes to the centrosome and along the neurite shaft bound to MTs. Depleting TPX2 decreases MT formation frequency specifically at the tip and the base of the neurite, and these correlate precisely with the regions where active GTP-bound Ran proteins are enriched. Furthermore, overexpressing the downstream effector of Ran, importin, compromises MT formation and neuronal morphogenesis. Finally, applying a Ran-importin signaling interfering compound phenocopies the effect of TPX2 depletion on MT dynamics. Together, these data suggest a model in which Ran-dependent TPX2 activation promotes acentrosomal MT nucleation in neurons.
The structural and electrical comparison of Y2O3 and Ti-doped Y2O3 dielectrics
(2017-02-15)
Lee, Ming Ling
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Kao, Chyuan Haur
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Chen, Hsiang
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Lin, Chan Yu
;
Chung, Yu Teng
A Ti-doped Y2O3(Y2Ti2O5) dielectric on polycrystalline silicon followed by rapid thermal annealing results in improved characteristics including a higher effective dielectric constant, higher breakdown electric field, lower electron trapping rate, and larger charge-to-breakdown when compared with Y2O3. The performance of high-k Y2O3 and Y2Ti2O5 dielectrics were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), capacitance-voltage, and current density-voltage. Incorporating Ti into the Y2O3 dielectric imparts improvements in the structural and electrical performance of the material. The Y2Ti2O5 dielectric with 800 degrees C annealing treatment has the best performance among all the samples tested.
Band-Engineered Local Cooling in Nanoscale Junctions
(2017-02-15)
Hsu, Bailey C.
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Chen, Yu-Chang
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電子物理學系
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Department of Electrophysics
The stability and performance of nanoscale junctions are closely related to the local effective temperature. The local effective temperature is mainly caused by the competition between heating and cooling processes in inelastic electron-phonon scat-tering. Local cooling occurs when the rate of energy in cooling exceeds that in heating. Previous research has been done using either specific potential configuration or an adatom to achieve local cooling. We propose an engineer-able localcooling mechanism in asymmetric two-terminal tunneling junctions, in which one electrode is made of metal, whereas the other is made of a selectable bad-metal, such as heavily-doped polysilicon. The width of energy window of the selectable material, defined as the width covering all possible energy states counting from the conduction band minimum, can be engineered through doping. Interestingly, we have shown that substantial local cooling can be achieved at room temperature when the width of energy window of the low-density electrode is comparable to the energy of the phonon. The unusual local cooling is caused by the narrowed width of energy window, which obstructs the inelastic scattering for heating.