Browsing by Issue Date, starting with "2015-12-15"

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Elliptic and parabolic equations in fractured media
(2015-12-15)
Yeh, Li-Ming
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應用數學系
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Department of Applied Mathematics
The elliptic and the parabolic equations with Dirichlet boundary conditions in fractured media are considered. The fractured media consist of a periodic connected high permeability sub-region and a periodic disconnected matrix block subset with low permeability. Let epsilon is an element of (0, 1] denote the size ratio of the matrix blocks to the whole domain and let omega(2) is an element of (0, 1] denote the permeability ratio of the disconnected subset to the connected sub-region. It is proved that the W-1,W-P norm of the elliptic and the parabolic solutions in the high permeability sub-region are bounded uniformly in omega, epsilon. However, the W-1,W-P norm of the solutions in the low permeability subset may not be bounded uniformly in omega, epsilon. For the elliptic and the parabolic equations in periodic perforated domains, it is also shown that the W-1,W-P norm of their solutions are bounded uniformly in epsilon. (C) 2015 Elsevier Inc. All rights reserved.
Tuning of the electron g factor in defect-free GaAs nanodisks
(2015-12-15)
Yang, Li-Wei
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Tsai, Yi-Chia
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Li, Yiming
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Higo, Aiko
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Murayama, Akihiro
We theoretically study the impact of changes in surroundings on the electron ground-state effective g factor in defect-free GaAs/AlGaAs nanodisks. To perform the study, we formulate and deploy a computational efficient full three-dimensional model to describe the effective g-factor tensor in semiconductor nano-objects of complex geometry and material content. This model is based on an effective 2 x 2 conduction-band Hamiltonian which includes the Rashba and Dresselhaus spin-orbit couplings. The description is suited to clarify the important question of the controllability of the electron effective g factor in semiconductor nano-objects. The results of this theoretical study suggest that in the defect-free GaAs/AlGaAs nanodisks, the effective g factor can be tuned within a wide range by proper design of the nanodisk environment. The zz components of the electron effective g-factor tensor obtained in our simulation are in good agreement with some recent experimental observations.
Universal brain signature of proficient reading: Evidence from four contrasting languages
(2015-12-15)
Rueckl, Jay G.
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Paz-Alonso, Pedro M.
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Molfese, Peter J.
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Kuo, Wen-Jui
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Bick, Atira
We propose and test a theoretical perspective in which a universal hallmark of successful literacy acquisition is the convergence of the speech and orthographic processing systems onto a common network of neural structures, regardless of how spoken words are represented orthographically in a writing system. During functional-MRI, skilled adult readers of four distinct and highly contrasting languages, Spanish, English, Hebrew, and Chinese, performed an identical semantic categorization task to spoken and written words. Results from three complementary analytic approaches demonstrate limited language variation, with speech-print convergence emerging as a common brain signature of reading proficiency across the wide spectrum of selected languages, whether their writing system is alphabetic or logographic, whether it is opaque or transparent, and regardless of the phonological and morphological structure it represents.
Visible-Light Modulation on Lattice Dielectric Responses of a Piezo-Phototronic Soft Material
(2015-12-16)
Huang, E-Wen
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Hsu, Yu-Hsiang
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Chuang, Wei-Tsung
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Ko, Wen-Ching
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Chang, Chung-Kai
The Yang-Mills gradient flow and SU(3) gauge theory with 12 massless fundamental fermions in a colour-twisted box
(2015-12-16)
Lin, C. -J. David
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Ogawa, Kenji
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Ramos, Alberto
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物理研究所
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Institute of Physics
We perform the step-scaling investigation of the running coupling constant, using the gradient-flow scheme, in SU(3) gauge theory with twelve massless fermions in the fundamental representation. The Wilson plaquette gauge action and massless unimproved staggered fermions are used in the simulations. Our lattice data are prepared at high accuracy, such that the statistical error for the renormalised coupling, g(GF), is at the subpercentage level. To investigate the reliability of the continuum extrapolation, we employ two different lattice discretisations to obtain g(GF). For our simulation setting, the corresponding gauge-field averaging radius in the gradient flow has to be almost half of the lattice size, in order to have this extrapolation under control. We can determine the renormalisation group evolution of the coupling up to g(GF)(2) similar to 6, before the onset of the bulk phase structure. In this infrared regime, the running of the coupling is significantly slower than the two-loop perturbative prediction, although we cannot draw definite conclusion regarding possible infrared conformality of this theory. Furthermore, we comment on the issue regarding the continuum extrapolation near an infrared fixed point. In addition to adopting the fit ansatz a'la Symanzik for performing this task, we discuss a possible alternative procedure inspired by properties derived from low-energy scale invariance at strong coupling. Based on this procedure, we propose a finite-size scaling method for the renormalised coupling as a means to search for infrared fixed point. Using this method, it can be shown that the behaviour of the theory around g(GF)(2) similar to 6 is still not governed by possible infrared conformality.
重新調序緩衝器
(2015-12-16)
陳紹基
;
黃紳睿
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王柏崴
一種重新調序緩衝器，其係將原先之位元反向輸出轉變成自然順序之輸出，係將記憶體分成兩組單埠的第一記憶體模組及第二記憶體模組，分別具有m個單埠記憶體單元，每一單元儲存有N/2m筆位元資料。透過寫入交換器將快速傅利葉轉換處理器之輸出做適當之交換，並寫入第一記憶體模組或第二記憶體模組中之m個單埠記憶體單元；再藉由讀出交換器將第一記憶體模組或第二記憶體模組之m個單埠記憶體單元中的位元資料依自然順序讀出並且做適當之交換後輸出，能達到連續性的快速傅立葉運算位元反相轉換之功效，並具有極佳之記憶體面積效益。
偏壓電路
(2015-12-16)
王毓駒
;
儲青雲
一種偏壓電路，適用於偏壓一個待偏壓轉導元件，使得該待偏壓轉導元件的轉導值是恆定的。該偏壓電路包含一個轉換器及一個控制器。該轉換器接收一個第一電流信號及一個第二電流信號，且根據該第一電流信號及該第二電流信號，產生一個第一電壓信號、一個第二電壓信號及一個用於偏壓該待偏壓轉導元件的偏壓電壓。該控制器從該轉換器接收該第一電壓信號及該第二電壓信號，且根據該第一電壓信號及該第二電壓信號，產生給該轉換器的該第一電流信號及該第二電流信號，以使該第一電壓信號的幅值相同於該第二電壓信號的幅值。
血液脈波內生特徵分割系統與方法
(2015-12-16)
張家齊
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蕭子健
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許弘毅
一種血液脈波內生特徵分割方法藉由一處理器執行，該方法包括以下步驟：(A)取得一期間內的一原始血液脈波訊號；(B)依據一設定規則尋找該血液脈波訊號的一趨勢特徵；(C)從該血液脈波訊號中分割該特徵訊號，形成一去除特徵訊號；(D)以該去除特徵訊號取代該血液脈波訊號；(E)重複執行步驟(B)至(D)直至一預設時間，其中該預設時間小於/等於該期間；(F)輸出第L次分割後的訊號，並作為一第一處理訊號，其中L為正整數；以及(G)從該血液脈波訊號中分割掉該第一處理訊號，藉此取得一第一內生特徵。
人工視網膜系統
(2015-12-16)
吳重雨
;
林伯剛
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焦傳金
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潘瑞文
一種人工視網膜系統，包含一光學裝置及一視網膜植入裝置，該光學裝置包括一影像產生器，該影像產生器用以接收一外部影像，並將該外部影像依序轉換成第一至第M分別具有N個投射區塊的投射影像，每一投射區塊具有M個相同的投射圖像。而該視網膜植入裝置包括一具有N個像素區塊的像素陣列，每一像素區塊分別對應該每一投射區塊，每一像素區塊根據所對應的投射區塊的M個投射圖像進行光電轉換而匯集成一電刺激，以提高該人工視網膜系統的電刺激效率，其中，M≧2，N≧2，且M、N為正整數。
Effects of dynamic polarization on boron-doped NCD properties and on its performance for electrochemical-analysis of Pb (II), Cu (II) and Hg (II) in aqueous solution via direct LSV
(2015-12-17)
Nurhayati, Ervin
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Juang, Yaju
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Rajkumar, Muniyandi
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Huang, Chihpin
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Hu, Chi-Chang
Boron-doped diamond films electrode has been effectively applied in electroanalysis to detect numerous kinds of electroactive chemicals including heavy metals. The success of this application not only depends on the original quality of the films, but more than that, surface treatment or activation and analytical method applied play important role. Fabricated boron-doped nanocrystalline diamond (BD-NCD) in this work were electrochemically pretreated prior to the measurement of heavy metal ions in the solution. The surface properties of the films were evaluated with FE-SEM, AFM, Raman spectroscopy and XPS. The technique chosen for heavy metal measurement was linear sweep voltammetry (LSV) after comparing with differential pulse and square wave voltammetry. In this study, dynamic polarization applied on the BD-NCD electrode was proven to enhance its surface properties. The result of XPS analysis shows that polarized electrode exhibits diminution of Csp(2) and possess minimum adventitious carbon content on its surface. This leads to an increase of electrode kinetic and promotes its capability for Pb, Cu and Hg ions measurements in the aqueous solution using LSV technique without pre-concentration step. The linearity of current response with increasing heavy metals concentration in an acetate buffer is ranging from 1 to 22.5 mu M for Pb and Cu ions and 1 to 10 mu M for Hg ion. The detection limit and sensitivity are 1.339, 0.102 and 0.666 mu M, and 0.014, 0.104 and 0.057 mu A mu M-1 mm(2) for Pb, Cu and Hg, respectively. The BD-NCD electrode also exhibits capability in simultaneous multi-metals determination although the presence of Cu ion was found to be a disturbance in the system as well. On the other hand, the high content of organics in the real water sample such as lake water also demonstrated to hinder heavy metals measurement. Thus, this study confirms that the BD-NCD after undergoing dynamic polarization are capable of direct determination of Pb, Cu and Hg ions both individually and simultaneously either in the acetate buffer solution or natural water system, within mu M level. (C) 2015 Elsevier B.V. All rights reserved.
Fragmentation fractions of two-body b-baryon decays
(2015-12-17)
Hsiao, Y. K.
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Lin, P. Y.
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Luo, L. W.
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Geng, C. Q.
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電子物理學系
We study the fragmentation fractions (f(Bb)) of the b-quark to b-baryons (B-b). By the assumption of f(Lambda b)/(f(u) + f(d)) = 0.25 +/- 0.15 in accordance with the measurements by LEP, CDF and LHCb Collaborations, we estimate that f(Lambda b)= 0.175 +/- 0.106 and f(Xi b)(-),0 = 0.019 +/- 0.013. From these fragmentation fractions, we derive B(Lambda(b) -> J/psi Lambda) =(3.3 +/- 2.1) x10(-4), B(Xi(-)(b) -> J/psi Xi(-)) = (5.3 +/- 3.9) x10(-4) and B(Omega(-)(b) -> J/psi Omega(-)) > 1.9 x10(-5). The predictions of B(Lambda(b) -> J/psi Lambda) and B(Xi(-)(b) -> J/psi Xi(-)) clearly enable us to test the theoretical models, such as the QCD factorization approach in the b-baryon decays. (C) 2015 The Authors. Published by Elsevier B.V.
Enhanced photocatalytic degradation of sulfamethoxazole by visible-light-sensitive TiO2 with low Cu addition
(2015-12-17)
Chiang, Li-Fen
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Doong, Ruey-an
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環境工程研究所
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Institute of Environmental Engineering
In this study, the one-pot microwave-assisted impregnation method was developed to prepare the visible-light-sensitive Cu-TiO2 at low mass ratios of 0.006-0.063 wt% for the enhanced photocatalytic degradation of sulfamethoxazole (SMX) under visible light irradiation. The electron probe microanalysis and X-ray absorbance near-edge spectroscopic results indicated that the distribution of copper ions was even on TiO2 nanoparticles and the dominant species of copper element was CuO. The photodegradation efficiency and rate of SMX by Cu-TiO2 increased positively upon increasing Cu loading from 0.006 to 0.045 wt% Cu and then decreased when further increasing the Cu mass loading to 0.063 wt%. The pseudo-first-order rate constants for SMX photodegradation by Cu-TiO2 were in the range 0.0103-0.0506 min-1, which were 1.9-13.1 times higher than that of pure Degussa P25 TiO2. The photodegradation efficiency and rate of SMX can be maintained in the pH range of 5-9, and the release of Cu ions in the solution was only few 1.1.g/L, which indicates the stability of Cu-TiO2 during the photocatalytic reaction in aqueous solutions. In addition, the Cu-TiO2 could be recycled for at least 4 cycles and maintained the highly stable photoactivity toward SMX degradation under visible light irradiation. Results obtained in this study clearly demonstrate that low mass loading of Cu(II) onto TiO2 can effectively shorten the route of electron transfer and can serve as the efficient visible-light-driven photocatalysts for photodegradation of SMX and other pharmaceutical products. (C) 2015 Elsevier B.V. All rights reserved.
Cooperativity and Site-Selectivity of Intramolecular Hydrogen Bonds on the Fluorescence Quenching of Modified GFP Chromophores
(2015-12-18)
Chang, Deng-Hsiang
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Ou, Chun-Lin
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Hsu, Hung-Yu
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Huang, Guan-Jhih
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Kao, Chen-Yi
This paper provides the first example of experimentally characterized hydrogen-bond cooperativity on fluorescence quenching with a modified green fluorescence protein (GFP) chromophore that contains a 6-membered C=N center dot center dot center dot H-O and a 7-membered C=O center dot center dot center dot H-O intramolecular H-bonds. Variable-temperature H-1 NMR and electronic absorption and emission spectroscopies were used to elucidate the preference of intra- vs intermolecular H-bonding at different concentrations (1 mM and 10 mu M), and X-ray crystal structures provide clues of possible intermolecular H-bonding modes. In the ground state, the 6-membered H-bond is significant but the 7-membered one is rather weak. However, fluorescence quenching is dominated by the 7-membered H-bond, indicating a strengthening of the H-bond in the excited state. The H-bonding effect is more pronounced in more polar solvents, and no intermediates were observed from femtosecond fluorescence decays. The fluorescence quenching is attributed to the occurrence of diabatic excited-state proton transfer. Cooperativity Of the two intramolecular H-bonds on spectral shifts and fluorescence quenching is evidenced by comparing with both the single H-bonded and the non-H-bonded counterparts. The H-bond cooperativity does not belong to the conventional patterns of sigma- and pi-cooperativity but a new type of polarization interactions, which demonstrates the significant interplay of H-bonds for multiple H-bonding systems in the electronically excited states.
Diffusion of a massive particle in a periodic potential: Application to adiabatic ratchets
(2015-12-18)
Rozenbaum, Viktor M.
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Makhnovskii, Yurii A.
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Shapochkina, Irina V.
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Sheu, Sheh-Yi
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Yang, Dah-Yen
We generalize a theory of diffusion of a massive particle by the way in which transport characteristics are described by analytical expressions that formally coincide with those for the overdamped massless case but contain a factor comprising the particle mass which can be calculated in terms of Risken's matrix continued fraction method (MCFM). Using this generalization, we aim to elucidate how large gradients of a periodic potential affect the current in a tilted periodic potential and the average current of adiabatically driven on-off flashing ratchets. For this reason, we perform calculations for a sawtooth potential of the period L with an arbitrary sawtooth length (l < L) instead of the smooth potentials typically considered in MCFM-solvable problems. We find nonanalytic behavior of the transport characteristics calculated for the sharp extremely asymmetric sawtooth potential at l -> 0 which appears due to the inertial effect. Analysis of the temperature dependences of the quantities under study reveals the dominant role of inertia in the high-temperature region. In particular, we show, by the analytical strong-inertia approach developed for this region, that the temperature-dependent contribution to the mobility at zero force and to the related effective diffusion coefficient are proportional to T-3/2 and T-1/2, respectively, and have a logarithmic singularity at l -> 0.
In-Situ Probing Plasmonic Energy Transfer in Cu(In, Ga)Se-2 Solar Cells by Ultrabroadband Femtosecond Pump-Probe Spectroscopy
(2015-12-18)
Chen, Shih-Chen
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Wu, Kaung-Hsiung
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Li, Jia-Xing
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Yabushita, Atsushi
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Tang, Shih-Han
In this work, we demonstrated a viable experimental scheme for in-situ probing the effects of Au nanoparticles (NPs) incorporation on plasmonic energy transfer in Cu(In, Ga)Se-2 (CIGS) solar cells by elaborately analyzing the lifetimes and zero moment for hot carrier relaxation with ultrabroadband femtosecond pump-probe spectroscopy. The signals of enhanced photobleach (PB) and waned photoinduced absorption (PIA) attributable to surface plasmon resonance (SPR) of Au NPs were in-situ probed in transient differential absorption spectra. The results suggested that substantial carriers can be excited from ground state to lower excitation energy levels, which can reach thermalization much faster with the existence of SPR. Thus, direct electron transfer (DET) could be implemented to enhance the photocurrent of CIGS solar cells. Furthermore, based on the extracted hot carrier lifetimes, it was confirmed that the improved electrical transport might have been resulted primarily from the reduction in the surface recombination of photoinduced carriers through enhanced local electromagnetic field (LEMF). Finally, theoretical calculation for resonant energy transfer (RET)-induced enhancement in the probability of exciting electron-hole pairs was conducted and the results agreed well with the enhanced PB peak of transient differential absorption in plasmonic CIGS film. These results indicate that plasmonic energy transfer is a viable approach to boost high-efficiency CIGS solar cells.
在地青年返鄉　深耕苗栗
(2015-12-20)
許雅筑
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Department of Communication and Technology
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傳播與科技學系
「老家，屬於每一個人的家。」短短一句經營理念，道出陳鵬文對家鄉人文的眷戀與情分。
台灣高等教育　本質流失
(2015-12-20)
曾煥富
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Department of Communication and Technology
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傳播與科技學系
台灣教育本質上，擁有內容上的不健全與矛盾。
台灣高教敲警鐘
(2015-12-20)
王雪琪
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Department of Communication and Technology
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傳播與科技學系
台灣高等教育所面對的危機，主因是不是少子化造成的？
MOOCs熱潮　高教危機轉機
(2015-12-20)
許馨仁
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Department of Communication and Technology
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傳播與科技學系
我國於二〇一四年提出「磨課師分項計畫」，引進西方MOOC數位學習模式。政策施行至今，產生不少爭議。
總編輯的話
(2015-12-20)
吳和謙
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Department of Communication and Technology
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傳播與科技學系
本期為喀報第兩百三十一期，共有十二篇稿件。類目以社會議題為主，相當充實，側欄廣告則以即將到來的聖誕節為主題，溫馨動人。