Browsing by Issue Date, starting with "2014-01-14"

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Side Chain Structure Affects the Photovoltaic Performance of Two-Dimensional Conjugated Polymers
(2014-01-14)
Jiang, Jian-Ming
;
Lin, His-Kuei
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Lin, Yu-Che
;
Chen, Hsiu-Cheng
;
Lan, Shang-Che
We used Stille coupling of electron-rich benzo[1,2-b:4,5-b']dithiophene (BDT) presenting conjugated alkylthiophene (T), alkylphenyl (P), or alkylfuran (F) side chains with electron-deficient alkoxy-modified 2,1,3-benzooxadiazole (BO) moieties to obtain a series of two-dimensional, conjugated, D-pi-A polymers (PBDTTBO, PBDTPBO, and PBDTFBO). The side chains of the BDT units altered the solubility, conformations, and electronic properties of the synthesized conjugated, polymers, allowing tuning of their photovoltaic properties when blended with fullerenes. Density functional theory calculations revealed that the presence of these side chain groups on the BDT donor units affected the torsion angles between the side chain groups and the conjugated main chains but resulted in only slightly different energy levels for the highest occupied molecular orbitals for these polymers, consistent with results obtained experimentally using cyclic voltammetry. These polymers displayed excellent thermal stabilities (5 wt % degradation temperatures: >330 degrees C) and broad spectral absorptions (from 450 to 700 nm). Transmission electron microscopy images revealed that the morphologies of active layers comprising these two-dimensional conjugated polymers and the fullerene derivative PC71BM did, however, vary substantially depending on the structure of the side chains that affects the solubility of the polymers. As a result, the efficiencies of photovoltaic devices incorporating PBDTFBO, PBDTPBO, or PBDTTBO polymers and PC71BM varied greatly, from 3.6 to 5.9%. When using 1-chloronaphthalene (1 vol %) or 1,8-diiodooctane (1 vol %) as an additive for processing the active layer, the power conversion efficiencies (PCEs) of photovoltaic devices incorporating blends of PBDTFBO, PBDTPBO, or PBDTTBO and PC71BM (1:2) improved to 5.4, 6.4, and 7.4%, respectively, due to their optimized morphologies, with the PCE of 7.4% being among the highest values reported for conjugated polymers involving BO moieties. Thus, the photovoltaic properties of these conjugated polymers were highly tunable through slight modifications of their side chain structures.
Rayleigh Instability in Polymer Thin Films Coated in the Nanopores of Anodic Aluminum Oxide Templates
(2014-01-14)
Tsai, Chia-Chan
;
Chen, Jiun-Tai
;
應用化學系
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Department of Applied Chemistry
We study the Rayleigh instability of polystyrene (PS) thin films coated in the nanopores of anodic aluminum oxide (AAO) templates. After thermal annealing, the surface of the PS thin films undulates and the nanostructures transform from nanotubes to Rayleigh-instability-induced nanostructures (short nanorods with encapsulated air bubbles). With longer annealing times, the nanostructures further transform to nanorods with longer lengths. PS samples with two different molecular weights (24 and 100 kg/mol) are used, and their instability transformation processes are compared. The morphology diagrams of the nanostructures at different stages are also constructed to elucidate the mechanism of the morphology transformation.
Development of approximate solutions for contaminant transport through fractured media
(2014-01-15)
Liu, Chih-Tien
;
Yeh, Hund-Der
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環境工程研究所
;
Institute of Environmental Engineering
Approximate solutions are sometimes very convenient and useful in engineering practices if the analytical solution is in a complicated form and difficult to evaluate accurately. This study develops four different approximate solutions for the problem of contaminant transport in fractured media presented in Tang et al. (1981) [1]. Their problem was solved analytically and the solutions of concentration distributions in the fracture and the rock expressed in infinite integrals had to rely on numerical approaches to obtain the results. The approximate solutions we develop herein include small-time solution, large-time solution, low-order approximate solution and high-order one based on the Pade approximation technique. The small-time solution gives very accurate concentrations at early times while the large-time solution yields excellent predictions at late times, as compared to Tang et al.\'s solution (Tang et al., 1981) [1]. In contrast, the solution based on low-order Fade approximation with polynomials of degree one in the numerator and degree two in the denominator gives fairly good predictions over the entire time domain, especially in the intermediate period as compared with those of the small-time and large-time solutions. In addition, the solution based on high-order Fade approximation with polynomials of degree two in the numerator and degree three in the denominator is also developed and its predicted concentrations are also compared with Tang et al.\'s solution (Tang et al., 1981) [1]. These results reveal that the Fade approximation has an advantage of being capable of producing more accurate results than the relationships of SPLT and LPST in the intermediate and late time periods. (C) 2014 Elsevier Inc. All rights reserved.
Andrographolide downregulates the v-Src and Bcr-Abl oncoproteins and induces Hsp90 cleavage in the ROS-dependent suppression of cancer malignancy
(2014-01-15)
Liu, Sheng-Hung
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Lin, Chao-Hsiung
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Liang, Fong-Ping
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Chen, Pei-Fen
;
Kuo, Cheng-Deng
Andrographolide is a diterpenoid compound isolated from Andrographis paniculata that exhibits anticancer activity. We previously reported that andrographolide suppressed v-Src-mediated cellular transformation by promoting the degradation of Src. In the present study, we demonstrated the involvement of Hsp90 in the andrographolide-mediated inhibition of Src oncogenic activity. Using a proteomics approach, a cleavage fragment of Hsp90 alpha was identified in andrographolide-treated cells. The concentration- and time-dependent induction of Hsp90 cleavage that accompanied the reduction in Src was validated in RK3E cells transformed with either v-Src or a human truncated c-Src variant and treated with andrographolide. In cancer cells, the induction of Hsp90 cleavage by andrographolide and its structural derivatives correlated well with decreased Src levels, the suppression of transformation, and the induction of apoptosis. Moreover, the andrographolide-induced Hsp90 cleavage, Src degradation, inhibition of transformation, and induction of apoptosis were abolished by a ROS inhibitor, N-acetyl-cysteine. Notably, Hsp90 cleavage, decreased levels of Bcr-Abl (another known Hsp90 client protein), and the induction of apoptosis were also observed in human K562 leukemia cells treated with andrographolide or its active derivatives. Together, we demonstrated a novel mechanism by which andrographolide suppressed cancer malignancy that involved inhibiting Hsp90 function and reducing the levels of Hsp90 client proteins. Our results broaden the molecular basis of andrographolide-mediated anticancer activity. (C) 2013 Elsevier Inc. All rights reserved.
Is energy pooling necessary in ultraviolet matrix-assisted laser desorption/ionization?
(2014-01-15)
Lin, Hou-Yu
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Song, Botao
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Lu, I-Chung
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Hsu, Kuo-Tung
;
Liao, Chih-Yu
RATIONALEEnergy pooling has been suggested as the key process for generating the primary ions during ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI). In previous studies, decreases in fluorescence quantum yields as laser fluence increased for 2-aminobenzoic acid, 2,5-dihydroxybenzoic acid (2,5-DHB), and 3-hydroxypicolinic acid were used as evidence of energy pooling. This work extends the research to other matrices and addresses whether energy pooling is a universal property in UV-MALDI. METHODSEnergy pooling was investigated in a time-resolved fluorescence experiment by using a short laser pulse (355nm, 20ps pulse width) for excitation and a streak camera (1ps time resolution) for fluorescence detection. RESULTSThe excited-state lifetime of 2,5-DHB decreased with increases in laser fluence. This suggests that a reaction occurs between two excited molecules, and that energy pooling may be one of the possible reactions. However, the excited-state lifetime of 2,4,6-trihydroxyacetophenone (THAP) did not change with increases in laser fluence. The upper limit of the energy pooling rate constant for THAP is estimated to be approximately 100-500 times smaller than that of 2,5-DHB. CONCLUSIONSThe small energy pooling rate constant for THAP indicates that the potential contribution of the energy pooling mechanism to the generation of THAP matrix primary ions should be reconsidered. Copyright (c) 2013 John Wiley & Sons, Ltd.
Structural characterizations of PtRu nanoparticles by galvanostatic pulse electrodeposition
(2014-01-15)
Hsieh, Yu-Chi
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Chang, Li-Chung
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Tseng, Yuan-Chieh
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Wu, Pu-Wei
;
Lee, Jyh-Fu
We demonstrate that the compositions and structures of PtRu nanoparticles can be altered via adjusting plating variables during galvanostatic pulse electrodeposition. During current-on time (Ton), both Pt and Ru are deposited according to their respective diffusion-limiting current. However, during current-off time (Toff), due to difference in the redox potentials, a displacement reaction is occurring that leads to the reduction of Pt ions from the electrolyte while the Ru atoms in the PtRu nanoparticles experience oxidation reaction and corrosive dissolution simultaneously. Therefore, the duty cycle, defined as Ton/(Ton + Toff), serves as an indicator for the severity of displacement reaction that affects the PtRu makeup. Inductively-coupled mass spectrometry determines the composition as Pt83Ru17, Pt64Ru36, and Pt53Ru47 for duty cycles of 0.077, 0.111, and 0.333, respectively. Images from transmission electron microscope exhibit nanoparticles in sizes of 4-11 nm. Analysis from extended X-ray absorption fine structure (EXAFS) suggests that Pt atoms tend to segregate outward and reside at the alloy's surface upon the displacement reaction. Composition profiles from line scans of energy dispersive X-ray spectroscopy are consistent with atomic structure revealed by EXAFS. (C) 2013 Elsevier B.V. All rights reserved.
An immersed boundary method for simulating the dynamics of three-dimensional axisymmetric vesicles in Navier-Stokes flows
(2014-01-15)
Hu, Wei-Fan
;
Kim, Yongsam
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Lai, Ming-Chih
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應用數學系
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數學建模與科學計算所(含中心)
In this paper, we develop a simple immersed boundary method to simulate the dynamics of three-dimensional axisymmetric inextensible vesicles in Navier-Stokes flows. Instead of introducing a Lagrange's multiplier to enforce the vesicle inextensibility constraint, we modify the model by adopting a spring-like tension to make the vesicle boundary nearly inextensible so that solving for the unknown tension can be avoided. We also derive a new elastic force from the modified vesicle energy and obtain exactly the same form as the originally unmodified one. In order to represent the vesicle boundary, we use Fourier spectral approximation so we can compute the geometrical quantities on the interface more accurately. A series of numerical tests on the present scheme have been conducted to illustrate the applicability and reliability of the method. We first perform the accuracy check of the geometrical quantities of the interface, and the convergence check for different stiffness numbers as well as fluid variables. Then we study the vesicle dynamics in quiescent flow and in gravity. Finally, the shapes of vesicles in Poiseuille flow are investigated in detail to study the effects of the reduced volume, the confinement, and the mean flow velocity. The numerical results are shown to be in good agreement with those obtained in literature. (C) 2013 Elsevier Inc. All rights reserved.
Electrical properties of SiGe nanowire following fluorine/nitrogen plasma treatment
(2014-01-15)
Chang, Kow-Ming
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Chen, Chu-Feng
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Lai, Chiung-Hui
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Kuo, Po-Shen
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Chen, Yi-Ming
The improvements to electrical properties of SiGe nanowires by surface plasma treatment were investigated. Various durations of pre-oxidation with fluorine; ambients for post-nitridation plasma treatment, and annealing temperature after plasma treatment, 800-950 degrees C, were applied. Pre-oxidation treatment using fluorine plasma; improved the conductance of SiGe nanowires because the Si-F binding energy created a more stable interface state than bare nanowire on the surface of SiGe. N-2 plasma incorporated more N than does in NH3 plasma, and NH3 has the drawback of introducing electron traps, causing Si-H bonds to break in the subsequent annealing process. Since the reparation of surface defects by plasma treatment is valid, the high post-annealing temperature to reduce defect by re-crystallizing can be reduced. Hence, Ge diffusion at low post-annealing temperature did not reduce the high concentration of Ge at the SiGe nanowire surfaces. (C) 2013 Elsevier B.V. All rights reserved.
A conservative scheme for solving coupled surface-bulk convection-diffusion equations with an application to interfacial flows with soluble surfactant
(2014-01-15)
Chen, Kuan-Yu
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Lai, Ming-Chih
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應用數學系
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數學建模與科學計算所(含中心)
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Department of Applied Mathematics
Many physical problems arising in biological or material sciences involve solving partial differential equations in deformable interfaces or complex domains. For instance, the surfactant (an amphiphilic molecular) which usually favors the presence in the fluid interface may couple with the surfactant soluble in one of bulk domains through adsorption and desorption processes. Thus, it is important to accurately solve coupled surface-bulk convection-diffusion equations especially when the interface is moving. In this paper, we first rewrite the original bulk concentration equation in an irregular domain (soluble region) into a regular computational domain via the usage of the indicator function so that the concentration flux across the interface due to adsorption and desorption processes can be termed as a singular source in the modified equation. Based on the immersed boundary formulation, we then develop a new conservative scheme for solving this coupled surface-bulk concentration equations which the total surfactant mass is conserved in discrete sense. A series of numerical tests has been conducted to validate the present scheme. As an application, we extend our previous work [M.-C. Lai, Y.-H. Tseng, H. Huang, An immersed boundary method for interfacial flows with insoluble surfactant, J. Comput. Phys. 227 (2008) 7279-7293] to the soluble case. The effects of solubility of surfactant on drop deformations in a quiescent and shear flow are investigated in detail. (C) 2013 Elsevier Inc. All rights reserved.
Secondary optical element design for intracorporeal LED illumination system
(2014-01-15)
Pan, Jui-Wen
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Su, Ying-Chieh
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Chen, Yao-Shan
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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
In this Letter, we propose an intracorporeal illumination system for providing uniform and wide-field illumination during minimally invasive surgery. The illumination system is comprised of an Alexis wound retractor, a set of LEDs, and secondary optical elements (SOEs). The SOE was composed of a Fresnel lens and a total internal reflection lens, which was designed to improve the optical performance of the LED. The results of simulation demonstrate that the optical efficiency of each LED with an SOE could be increased from 33.6% to 82.9%. To avoid damage to human tissue by thermal effect, the number of LEDs with SOEs was optimized. The results indicate that our design to be applicable for practical surgery. (C) 2014 Optical Society of America
靜態隨機存取記憶裝置及其位元線電壓控制電路
(2014-01-16)
莊景德
;
連南鈞
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廖偉男
;
張琦昕
;
楊皓義
一種靜態隨機存取記憶裝置及其位元線電壓控制電路，位元線電壓控制電路包括控制器、電壓上拉電路、電壓下拉電路以及電壓維持器。控制器接收記憶庫選擇信號以及時脈信號，依據記憶庫選擇信號以及時脈信號來決定上拉時間週期、下拉時間週期以及電壓維持時間週期。電壓上拉電路在上拉時間週期依據第一參考電壓上拉位元線電源。電壓下拉電路在下拉時間週期依據第二參考電壓下拉位元線電源。電壓維持器在電壓維持時間週期使位元線電源維持等於輸出電壓。其中，電壓維持時間週期在上拉時間週期以及下拉時間週期之後。
腹式發聲辨識系統與方法
(2014-01-16)
蕭子健
;
崔維軒
本發明揭露一種一種腹式發聲辨識系統及方法，其係用於判斷一使用者發聲之品質，其先使用一呼吸感測器與一麥克風，同步擷取發聲時之一聲音訊號和胸部與腹部之一胸部呼吸訊號及一腹部呼吸訊號，再對該聲音訊號、該胸部呼吸訊號、及該腹部呼吸訊號執行西爾伯特黃轉換分析，之後，評估發聲時之腹式換氣是否正確，並判斷發聲方式是否正確。
晶圓次微米接合方法及其接合層
(2014-01-16)
陳冠能
;
張耀仁
本發明提供一種晶圓次微米接合方法及其接合層。本發明之接合層包含有一位於晶圓之欲接合表面上的底部金屬層，一位於底部金屬層上的中間擴散緩衝金屬層；一位於中間緩衝金屬層上且可與底部金屬共晶反應的上方金屬層，此中間擴散緩衝金屬層之熔點高於上方金屬層與底部金屬層。兩個表面形成有接合層之晶圓進行接合時，兩上方金屬層先液相接合，至中間擴散緩衝金屬層隨上方金屬層熔融後均勻分佈，底部金屬層與上方金屬層相互擴散，將上方金屬層完全消耗反應成為一具有低電阻之金屬共晶相位之化合物。
液晶透鏡結構及其電控液晶眼鏡結構
(2014-01-16)
陳宏山
;
林怡欣
本發明係揭露一種液晶透鏡結構及其電控液晶眼鏡結構。液晶透鏡結構包含一第一電極層、一複合層、一第二電極層及一第三電極層。複合層包含一第一配向層、一第一液晶層、一複合薄膜層、一第二液晶層及一第二配向層。第一配向層係位於第一電極層上。第一液晶層係位於第一配向層上。複合薄膜層係包含一液晶及一高分子材料，複合薄膜層係位於第一液晶層上。第二液晶層係位於複合薄膜層上。第二配向層係位於第二液晶層上。第二電極層係位於第二配向層上。第三電極層係位於第二電極層上。其中，第一配向層與第二配向層之配向方向係為相互垂直，且複合薄膜層中之液晶與高分子材料之配向方向係為相互垂直。
融合人臉辨識及語音辨識之身份辨識系統、其方法及其服務型機器人
(2014-01-16)
宋開泰
;
簡碩成
;
林昭宇
;
陳奕彣
;
陳信宏
本發明係揭露一種融合人臉辨識及語音辨識之身份辨識系統、其方法及其服務型機器人。此系統採用人臉辨識及語音辨識兩方的結果經過融合計算後產生最終結果。另外，此系統能藉由信心指數評估人臉辨識及語音辨識兩方辨識結果的可信度，若信心指數超出門檻值更納入融合計算。若只有一方的信心指數超過門檻值就只採納一方的結果做為輸出，如果兩方都超出門檻值則使用融合演算法輸出結果。
HUMAN IDENTIFICATION SYSTEM BY FUSION OF FACE RECOGNITION AND SPEAKER RECOGNITION, METHOD AND SERVICE ROBOT THEREOF
(2014-01-16)
SONG KAI-TAI
;
CHIEN SHUO-CHENG
;
LIN CHAO-YU
;
CHEN YI-WEN
;
CHEN SIN-HORNG
The present invention discloses a human identification system by fusion of face recognition and speaker recognition, a method and a service robot thereof. The system fuses results of the face recognition and the speaker recognition, and further uses confidence index to estimate the confidence level of the two recognition results. If only one of the confidence indices of the two recognition results reaches the threshold, then only this result is used as the output. If both confidence indices of the two recognition results reach the threshold, then the two recognition results are fused to output as a final result.
Atomic-Scale Variability and Control of III-V Nanowire Growth Kinetics
(2014-01-17)
Chou, Y. -C.
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Hillerich, K.
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Tersoff, J.
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Reuter, M. C.
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Dick, K. A.
In the growth of nanoscale device structures, the ultimate goal is atomic-level precision. By growing III-V nanowires in a transmission electron microscope, we measured the local kinetics in situ as each atomic plane was added at the catalyst-nanowire growth interface by the vapor-liquid-solid process. During growth of gallium phosphide nanowires at typical V/III ratios, we found surprising fluctuations in growth rate, even under steady growth conditions. We correlated these fluctuations with the formation of twin defects in the nanowire, and found that these variations can be suppressed by switching to growth conditions with a low V/III ratio. We derive a growth model showing that this unexpected variation in local growth kinetics reflects the very different supply pathways of the V and III species. The model explains under which conditions the growth rate can be controlled precisely at the atomic level.
交大e-News第156期
(2014-01-20)
Secretariat
;
國立交通大學秘書室
Infrared Spectra of Protonated Coronene and Its Neutral Counterpart in Solid Parahydrogen: Implications for Unidentified Interstellar Infrared Emission Bands
(2014-01-20)
Bahou, Mohammed
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Wu, Yu-Jong
;
Lee, Yuan-Pern
;
應用化學系
;
應用化學系分子科學碩博班
Large protonated polycyclic aromatic hydrocarbons (H(+)PAHs) are possible carriers of unidentified infrared (UIR) emission bands from interstellar objects, but the characterization of infrared (IR) spectra of large H(+)PAHs in the laboratory is challenging. IR absorption spectra of protonated coronene (1-C24H13+) and mono-hydrogenated coronene (1-C24H13.), which were produced upon electron bombardment of parahydrogen containing a small proportion of coronene (C24H12) during matrix deposition, were recorded. The spectra are of a much higher resolution than those obtained by IR multiphoton dissociation by Dopfer and co-workers. The IR spectra of protonated pyrene and coronene collectively appear to have the required chromophores for features of the UIR bands, and the spectral shifts on an increase in the number of benzenoid rings point in the correct direction towards the positions of the UIR bands. Larger protonated peri-condensed PAHs might thus be key species among the carriers of UIR bands.
氟硫化物黃光螢光材料、製備方法及其白光發光二極體
(2014-01-21)
陳登銘
;
吳昀錚
本發明揭露一種新穎的氟硫化物黃光螢光材料，其具有(A1-x-yCexBy)2Ca1-zSrzF4S2化學通式及四方晶系結構。其中的A及B可為除了Ce之外之相異的稀土金屬，且x、y、z的數值範圍分別為0<x≦1，0≦y≦1與0≦z≦1。另揭露上述螢光材料之製備方法及其白光發光二極體之應用。