Browsing by Issue Date, starting with "2009-02-15"

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Quantitative Assessment of Hepatic Fat of Intact Liver Tissues with Coherent Anti-Stokes Raman Scattering Microscopy
(2009-02-15)
Wu, Yao-Ming
;
Chen, Hung-Che
;
Chang, Wei-Tien
;
Jhan, Jhen-Wei
;
Lin, Hung-Lung
A fatty liver might progress from being a benign fatty liver, to steatohepatitis, cirrhosis, or even hepatocellular carcinoma. The great prevalence and severe outcome have warranted much investigation of the pathology and the development of effective therapies, which involve animal studies requiring critical evaluation of the hepatic fatty change. Histological examination and wet chemical analysis of liver biopsy specimens are generally employed for this purpose despite numerous procedures being involved. Using coherent anti-Stokes Raman scattering (CARS) microscopy, we have demonstrated the specific imaging of fat droplets in intact liver tissues and extracted the hepatic fat content through image analysis while eliminating laborious procedures required by traditional histopathological. examination. The content of hepatic fat measured with CARS imaging was correlated strongly with that determined by biochemical analysis (R(2) = 0.89) over a pathologically significant range of the hepatic fat (from 2% to 20% of the total mass of tissue). Our work validates the quantitative assessment of fat in intact tissue through the use of CARS microscopy. When combined with the increasingly diverse animal models of diseases related to metabolic disorders of lipids, our approach is extensible to enable acquiring important insight into the genetic, environmental, and dietary factors affecting the uptake and accumulation of fat within tissues.
Numerical study on micro-reformer performance and local transport phenomena of the plate methanol steam micro-reformer
(2009-02-15)
Hsueh, Ching-Yi
;
Chu, Hsin-Sen
;
Yan, Wei-Mon
;
機械工程學系
;
Department of Mechanical Engineering
The objective of this work is to investigate the transport phenomena and performance of a plate steam methanol micro-reformer. Micro channels of various height and width ratios are numerically analyzed to understand their effects on the reactant gas transport characteristics and micro-reformer performance. In addition, influences of Reynolds number and geometric size of micro channel on methanol conversion of micro-reformer and gas transport phenomena are also explored. The predicted results demonstrated that better performance is noted for a micro channel reformer with lower aspect-ratio micro channel. This is due to the larger the chemical reaction surface area for a lower aspect-ratio channel reformer. It is also found that the methanol conversion decreases with increasing Reynolds number Re. The results also indicate that the smaller micro channel size experiences a better methanol conversion. This is due to the fact that a smaller micro channel has a much more uniform temperature distribution, which in turn, fuel utilization efficiency is improved for a smaller micro channel reformer. (C) 2008 Elsevier B.V. All rights reserved.
Ultrafast optical probes of polaron dynamics in La0.7Ca0.3MnO3 thin films
(2009-02-15)
Wu, K. H.
;
Hsu, T. Y.
;
Shih, H. C.
;
Chen, Y. J.
;
Luo, C. W.
In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La0.7Ca0.3MnO3 (LCMO) thin films. The temporal evolution in transient reflectivity change Delta R/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.
Using C-band erbium-doped fiber amplifier with two-ring scheme for broadly wavelength-tuning fiber ring laser
(2009-02-15)
Yeh, C. H.
;
Shih, F. Y.
;
Wen, S.
;
Chow, C. W.
;
Chi, S.
In this demonstration, we propose and experimentally investigate a broad and stable wavelength-tuning fiber laser employing a C-band erbium-doped fiber amplifier (EDFA) and coupled-ring cavity scheme. Based on the proposed laser scheme, the wavelength-tuning range can be tuned in S- to C-bands (from 1510.0 to 1562.0 nm) due to the properly control of cavity loss. In addition, the performances of side-mode suppression ratio (SMSR), optical signal to noise ratio (OSNR), and output power and wavelength are also discussed and analyzed over the wavelength-tuning range. (C) 2008 Elsevier B.V, All rights reserved.
Organic light-emitting devices based on solution-processible quinolato-complex supramolecules
(2009-02-15)
Cheng, Jung-An
;
Chen, Chin H.
;
Shieh, Han-Ping D.
;
光電工程學系
;
顯示科技研究所
This paper discusses a new type of supramolecular material tris{5-N-[3-(9H-carbazol-9-yl)propyl]-N-(4-methylphenyl)aminesulfonyl-8-hydroxyquinolato} aluminum(III), Al(SCarq)(3), which we synthesized using three 5-N-[3-(9H-carbazol-9-yl)propyl]-N-(4-methylphenyl)aminesulfonyl-8-hydroxyquinoline as bidentate ligands. The peak photoluminescence in the solid phase appears at 488 nm. In cyclic voltammetric measurement, two oxidation peaks, which were obtained at -5.6 and -5.9eV, correspond to HOMO sites of carbazoyl and aluminum quinolates, respectively. in the investigation of solid morphological thin film, the flat surface was investigated using an atomic force microscope. The root mean square (rms) and mean roughness (R(a)) were respectively measured to be 0.427 and 0.343 nm. For the fabrication of organic light-emitting devices (OLEDs) using spin-coating techniques, the turn-on voltage and maximum luminescence of the optimized electroluminescence device, glass/ITO (20 nm)/PEDOT: PSS (75 nm)/Al(SCarq)(3) (85 nm)/BCP (8 nm)/LiF (1 nm)/Al (200 nm), were respectively 9.6 V and 35.0 cd m(-2). Due to the electroplex formation between the carbazole (electron-donor) and the aluminum quinolates (electron-acceptor) moieties under an applied DC bias, the chromaticity of electroluminescence shifted to green-yellow with 1931 CIE(x,y) (0.40, 0.47). (C) 2008 Elsevier B.V. All rights reserved.
Functional analysis of the evolutionarily conserved cis-regulatory elements on the sox17 gene in zebrafish
(2009-02-15)
Chan, Tzu-Min
;
Chao, Chung-Hao
;
Wang, Horng-Dar
;
Yu, Yen-Ju
;
Yuh, Chiou-Hwa
The Sox17 is an important transcription factor for endodermal cells (Danio rerio). According to the predictions of the GRNs, based on perturbation experiments and literature search, the sox17 gene is engaged with two other regulatory genes, sox32 and pou5f1. Nodal signaling operated on several endoderm-specific transcription factors to determine the endoderm specification. In addition, endoderm specification requires the Fgf and Bmp signaling pathways to be repressed in the cells which will become endoderm. It is predicted that Nodal activates sox32 and works synergistically with Pou5f1 to activate sox17 Bmp represses the expression of sox17 on the ventral side and Fgf represses it on the dorsal side. The regulatory inputs of sox17 at the genomic sequence level are not known. Here, we have uncovered the relevant sox17 cis-regulatory elements, and examined the specific input predictions of the GRNs. We discovered three conserved modules, A, 13, and C, with a synergistic effect among them. We revealed that the Pou5f1-binding element on the B module and the Sox32-binding element on the C module work synergistically. Furthermore, an evolutionarily non-conserved R module exhibits a repressive effect on both the ventral and dorsal side. We have directly demonstrated the structural and functional relationships of the genomic code at this key node of the endoderm GRNs in zebrafish development. This information provides new insight into the complexity of endoderm formation and serves as a valuable resource for the establishment of a complete endoderm gene regulatory network. (c) 2008 Elsevier Inc. All rights reserved.
Long paths in hypercubes with conditional node-faults
(2009-02-15)
Kueng, Tz-Liang
;
Liang, Tyne
;
Hsu, Lih-Hsing
;
Tan, Jimmy J. M.
;
資訊工程學系
Let F be a set of f <= 2n - 5 faulty nodes in an n-cube Q(n) such that every node of Q(n) still has at least two fault-free neighbors. Then we show that Q(n) - F contains a path of length at least 2(n) - 2f - 1 (respectively, 2(n) - 2f - 2) between any two nodes of odd (respectively, even) distance. Since the n-cube is bipartite, the path of length 2(n) - 2f - 1 (or 2(n) - 2f - 2) turns out to be the longest if all faulty nodes belong to the same partite set. As a contribution, our study improves upon the previous result presented by [J.-S. Fu, Longest fault-free paths in hypercubes with vertex faults, Information Sciences 176 (2006) 759-771] where only n - 2 faulty nodes are considered. (c) 2008 Elsevier Inc. All rights reserved.
Study of Al-Ti/Si bi-layer as the recording media for write-once HD-DVD optical disks
(2009-02-15)
Mai, Hung-Chuan
;
Hsieh, Tsung-Eong
;
Jeng, Shiang-Yao
;
Chen, Chong-Ming
;
Wang, Jen-Long
Optimum structure for HD-DVD optical disks containing Al-Ti/Si bi-layer recording system was identified by reflectivity simulation and dynamic test of disk samples. For the disk sample with optimized structure, the maximum partial response signal-to-noise ratio (PRSNR) of 19.1 dB, minimum simulated bit error rate (sbER) of 1.7 X 10(-7) and modulation >0.6 were achieved at the writing power (P(W)) = 11.2 mW. Transmission electron microscopy (TEM) revealed that the polycrystalline granular clusters constitute the recording marks. Subsequent analyses evidenced that element mixing/alloy reactions occur in between Si and Al-Ti layers and the formation of Al(3.21)Si(0.47) crystalline phase is responsible for the signal recording in the disk samples. (C) 2008 Elsevier B.V. All rights reserved.
Ultrafast optical probes of polaron dynamics in La(0.7)Ca(0.3)MnO(3) thin films
(2009-02-15)
Wu, K. H.
;
Hsu, T. Y.
;
Shih, H. C.
;
Chen, Y. J.
;
Luo, C. W.
In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La(0.7)Ca(0.3)MnO(3) (LCMO) thin films. The temporal evolution in transient reflectivity change Delta R/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.
螢光材料與發光裝置
(2009-02-16)
陳登銘
;
周怡君
一種螢光材料,其化學通式如下:A(B1-mEum^2+)PO4;其中A係選自Li、Na、K所組成之族群至少其中之一;B係選自Ca、Sr、Ba所組成之族群至少其中之一;其中0.0001≦m≦0.8。
Observation and analysis of coherent optical waves emitted from large-Fresnel number degenerate cavities
(2009-02-16)
Lu, T. H.
;
Lin, Y. C.
;
Chen, Y. F.
;
Huang, K. F.
;
電子物理學系
We demonstrate that the coherent optical waves emitted from large-Fresnel-number degenerate cavities persistently display a sort of salient intensity variations. We use the representation of the coherent states to explore the origin of the salient intensity variations and find that these coherent laser waves arise from a quadrature superposition of two degenerate coherent states. With the analytical representation of the superposed coherent states, we verify that these coherent laser waves possess a large angular momentum per photon. (c) 2009 Optical Society of America
Organic light-emitting diodes using 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane as p-type dopant
(2009-02-16)
Mi, Bao Xiu
;
Gao, Zhi Qiang
;
Cheah, Kok Wai
;
Chen, Chin H.
;
友訊交大聯合研發中心
We demonstrate that 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane (F2-HCNQ) can serve as an excellent electrical doping material for hole transport materials with the highest occupied molecular orbital level as high as 5.4 eV, such as N,N(')-di(naphthalene-1-yl)-N,N(')-diphenyl-benzidine (NPB). With its relatively strong electron-accepting ability and high thermal stability, F2-HCNQ doped NPB organic light-emitting diode (OLED) showed improved power efficiency with low driving voltage. The tris(8-hydroxyquinoline)aluminum based OLED with F2-HCNQ doped NPB layer and Cs(2)O doped bathophenanthroline electron transport layer exhibits power efficiency of 3.6 lm/W with driving voltage of 3.2 V at 100 cd/m(2).
Investigation of Ni-based thermal bimaterial structure for sensor and actuator application
(2009-02-16)
Huang, Chia-Sheng
;
Cheng, Yu-Ting
;
Chung, Junwei
;
Hsu, Wensyang
;
機械工程學系
Thermal bimaterial structures made of Ni and Ni-diamond nanocomposite for sensor and actuator application are proposed, fabricated, and tested. Two deflection types of thermal bimaterial structures, including upward and downward bending types, can be easily fabricated by controlling electroplating sequence of Ni and Ni-diamond nanocomposite. According to thermal performance measurement, the tip deflection of upward and downward types can reach about 82.5 mu m and -22.5 mu m for a temperature change of 200 degrees C, respectively. In the condition, the thermomechanical sensitivity and Output force are 412.5 nm/K and 97.0 mu N for upward type thermal bimaterial structure: and -112.5 nm/K and -26.5 mu N for downward type one. Due to the low electroplating process temperature (similar to 50 degrees C) for both Ni-based layers, diminutive pre-deformation of as-fabricated structure and strong interlaminar bonding strength are verified by SEM and vibrational test. The resonant frequency of the structure remains unchanged after 10(9) cycles. (C) 2008 Elsevier B.V. All rights reserved.
於矽基板上形成三族氮化物半導體磊晶層的方法
(2009-02-16)
張俊彥
;
楊宗
;
張哲榮
;
辜瑞泰
;
沈詩國
本發明為一種於矽基板上形成三族氮化物半導體磊晶層的方法,首先以氫氟酸溶液去除矽基板氧化物,再以高溫去除氟離子及污染物,產生平坦及重構之矽表面。接著以低溫沉積鋁原子層於矽基板上。在適當條件下,利用低射頻功率、低溫梯度變化等單一步驟同時形成單晶氮化矽絕緣層及氮化鋁成核層。且在富含鎵的條件下,以高溫成長氮化鎵層。
Primary Conformation Change in Bacteriorhodopsin on Photoexcitation
(2009-02-18)
Yabushita, Atsushi
;
Kobayashi, Takayoshi
;
電子物理學系
;
Department of Electrophysics
Ultrafast dynamics of bacteriorhodopsin (bR) has been extensively studied experimentally and theoretically. However, there are several contradictory results reported, indicating that its detailed dynamics and initial process have not yet been fully clarified. In this work, changes in the amplitude and phase of molecular vibration in the isomerization process of bR were real-time probed simultaneously at 128 different wavelengths through intensity modulation of the electronic transition. Systematic information on the transient change in continuous spectrum extending from 505 nm (2.45 eV) to 675 nm (1.84 eV) showed different dynamics in each spectral region reflecting the difference in the excited states and intermediates dominating the dynamics during the photoisomerization. Careful analysis of the transient spectral changes and spectrograms calculated from the vibrational real-time traces elucidated that the primary event just after photoexcitation is the deformation of the retinal configuration, which decays within 30 fs near the C=N bond in the protonated Schiff base. The intensity of C=N stretching mode starts to decrease before the initiation of the frequency modulation of the C=C stretching mode. The C=C stretching mode frequency was modulated by a coupled torsion around the C(13)=C(14) bond, leading to the photoisomerization around the bond. This study clarified the dynamics of the C=N and C=C stretching modes working as key vibration modes in the photoisomerization of bR. Furthermore, we have elucidated the modulation and decay dynamics of the C=C stretching mode in the photoreaction starting from H (Franck-Condon excited state) followed by I (twisted excited), and J (first intermediate) states.
Ordered polythiophene/fullerene composite core-shell nanorod arrays for solar cell applications
(2009-02-18)
Wang, Hsu-Shen
;
Lin, Li-Hua
;
Chen, Shih-Yung
;
Wang, Yuh-Lin
;
Wei, Kung-Hwa
For the first time, we have used melt-assisted wetting of porous alumina templates to prepare ordered core-shell nanorod arrays of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) for use in polymer solar cells. We characterized these arrays using tunneling electron microscopy and conductance atomic force microscopy, which revealed the presence of phase-separated shell (p-type) and core (n-type) regions. Under illumination, we observed a variation of several picoamperes between the currents in the core and shell regions of the P3HT/PCBM nanorod arrays.
半导体发光元件及其制作方法
(2009-02-18)
邱清华
;
黄泓文
;
郭浩中
;
卢廷昌
;
王兴宗
本发明有关一种半导体发光元件及其制作方法。半导体发光元件，包含基板、形成基板上的p型半导体层、形成p型半导体层上的发光层，及形成发光层上的n型半导体层，n型半导体层表面形成多数垂直基板方向且深度不小于0.2微米奈米柱体。藉加深奈米柱体深度可改变半导体发光元件发光场型，提升正向出光强度及发光效率。半导体发光元件制作方法包含：在第一基板上磊晶形成n型半导体层、发光层及p型半导体层；提供导电性基板，反转第一基板上磊晶结构层于导电基板上，使n型半导体层表面裸露；将多数球状颗粒散布n型半导体层表面做蚀刻遮罩；及以垂直导电基板方向蚀刻n型半导体层，形成多数深度不小于0.2微米奈米柱体。该制作方法可形成较大深度的奈米柱体，提高正向出光强度。
交大e-News第042期
(2009-02-20)
Secretariat
;
國立交通大學秘書室
Thermodynamics of a conformational change using a random walk in energy-reaction coordinate space: Application to methane dimer hydrophobic interactions
(2009-02-21)
Morozov, A. N.
;
Lin, S. H.
;
交大名義發表
;
National Chiao Tung University
A random walk sampling algorithm allows the extraction of the density of states distribution in energy-reaction coordinate space. As a result, the temperature dependences of thermodynamic quantities such as relative energy, entropy, and heat capacity can be calculated using first-principles statistical mechanics. The strategies for optimal convergence of the algorithm and control of its accuracy are proposed. We show that the saturation of the error [Q. Yan and J. J. de Pablo, Phys. Rev. Lett. 90, 035701 (2003); E. Belardinelli and V. D. Pereyra, J. Chem. Phys. 127, 184105 (2007)] is due to the use of histogram flatness as a criterion of convergence. An application of the algorithm to methane dimer hydrophobic interactions is presented. We obtained a quantitatively accurate energy-entropy decomposition of the methane dimer cavity potential. The presented results confirm the previous results, and they provide new information regarding the thermodynamics of hydrophobic interactions. We show that the finite-difference approximation, which is widely used in molecular dynamic simulations for the energy-entropy decomposition of a free energy potential, can lead to a significant error.
利用雙重負迴授之超寬頻低雜訊放大器
(2009-02-21)
傅昶綜
;
郭建男
本發明關於一種低雜訊之放大器,應用於射頻積體電路設計領域中,特別是超寬頻無線通訊系統之低雜訊放大器,至少包括具有該放大器之架構的核心電路之電晶體,與利用在其晶片上實現的變壓器,而組合成一雙重之負迴授,即“電感性負迴授"與“電容性負迴授"之放大器架構,其中,該電容性負迴授主要作用在中頻及低頻頻段,該電感性負迴授則作用在高頻頻段;結合此具有雙重負迴授路徑之放大電路,因而可在電路之信號輸入端提供非常寬頻且良好的阻抗匹配;本發明之低雜訊之放大器電路架構,可提供寬頻輸入阻抗匹配(broadband impedance match)及寬頻雜訊最佳化(broadband noise optimum)的最佳狀況,除了大幅提昇增益(gain)及增益平坦度(gain flatness)外,在雜訊性能上更有非常大的改善,且其耗電量仍可維持在非常小的程度。