Browsing by Issue Date, starting with "2011-07-04"

Now showing 1 - 20 of 40876

Hot carrier effect on gate-induced drain leakage current in high-k/metal gate n-channel metal-oxide-semiconductor field-effect transistors
(2011-07-04)
Dai, Chih-Hao
;
Chang, Ting-Chang
;
Chu, Ann-Kuo
;
Kuo, Yuan-Jui
;
Ho, Szu-Han
This paper investigates the channel hot carrier stress (CHCS) effects on gate-induced drain leakage (GIDL) current in high-k/metal-gate n-type metal-oxide-semiconductor field effect transistors. It was found that the behavior of GIDL current during CHCS is dependent upon the interfacial layer (IL) oxide thickness of high-k/metal-gate stacks. For a thinner IL, the GIDL current gradually decreases during CHCS, a result contrary to that found in a device with thicker IL. Based on the variation of GIDL current at different stress conditions, the trap-assisted band-to-band hole injection model is proposed to explain the different behavior of GIDL current for different IL thicknesses. (C) 2011 American Institute of Physics. [doi:10.1063/1.3608241]
A study of US and China's volatility spillover effects on Hong Kong and Taiwan
(2011-07-04)
Sheu, Her-Jiun
;
Cheng, Chien-Ling
;
經營管理研究所
;
Institute of Business and Management
Many international investors have taken interest in the Hong Kong, Taiwan, and China stock markets for diversification to explore higher returns owing to their rapid economic growth and increased link with international capital markets over the past decades. As correlation is primary component for asset risk managing, asset pricing and portfolio allocating, which are concerns for investors, it is crucial to clarify the co-movement of these stock markets. The aim of this paper was to compare the effect of volatility of China and U.S. stock market respectively on the Taiwan and Hong Kong. Both vector autoregressive (VAR) and multivariate generalized autoregressive conditional heteroskedastic (MGARCH) model were employed for two separated sub-periods: 1996-2005 and 2006-2009. Results indicated that while China's rapid economic growth and its integration with Taiwan and Hong Kong, its stock market was considerably independent and its co-moments with other (international) markets were still not significant. It's useful information for investors that China stock market, with low co-moments with others, would be a good risk diversified investment and that U.S. stock market, with high co-moments with others, would be a good pricing indicator.
Embedded biomimetic nanostructures for enhanced optical absorption in thin-film solar cells
(2011-07-04)
Tsai, Min-An
;
Han, Hao-Wei
;
Tsai, Yu-Lin
;
Tseng, Ping-Chen
;
Yu, Peichen
Light-management is critical to thin film solar cells due to their usually limited optical absorption in the active layer. Conventional approaches involve employing separate techniques for anti-reflection and light trapping. Here, we demonstrate an embedded biomimetic nanostructure (EBN) that achieves both effects for hydrogenated amorphous silicon (a-Si: H) solar cells. The fabrication of EBNs is accomplished by patterning an index-matching silicon-nitride layer deposited on a glass substrate using polystyrene nanospheres lithography, followed by reactive ion etching. The profile of EBN is then reproduced layer by layer during the deposition of a-Si: H cells. We show that a solar cell with an optimized EBN exhibits a broadband enhanced external quantum efficiency due to both antireflection and light-trapping, with respect to an industrial standard cell using an Asahi U glass substrate which is mostly optimized for light trapping. Overall, the cell with an optimized EBN achieves a large short-circuit current density of 17.74 mA/cm(2), corresponding to a 37.63% enhancement over a flat control cell. The power conversion efficiency is also increased from 5.36% to 8.32%. Moreover, the light management enabled by the EBN remains efficient over a wide range of incident angles up to 60 degrees, which is particularly desirable for real environments with diffused sun light. The novel patterning method is not restricted to a-Si:H solar cells, but is also widely applicable to other thin film materials. (C) 2011 Optical Society of America
Measuring competitive advantage with an asset-light valuation model
(2011-07-04)
Lin, Chiun-Sin
;
Huang, Chih-Pin
;
管理科學系
;
Department of Management Science
Defining competitive advantage as the ability of a firm to generate returns in excess of its synthetic normal returns; the present study develops an "asset-light" valuation model to capture intangible strategic resources, that do not appear on balance sheets and could explain abnormal returns. Three propositions are derived from the model: (1) firms emphasizing light assets over tangible assets, generate superior performance; (2) at a given level of synthetic normal returns, firms possessing more "light" assets have superior performance; and (3) to achieve a given book rate of return, firms with more light assets require fewer tangible assets as inputs. An empirical study of the global semiconductor industry significantly supports all three propositions. The results show that, the excess returns observed across an industry reflect heterogeneity in the "light assets" possessed by the firms, and provide an explanation for observed differences in performance.
Patterned structure of REMOTE PHOSPHOR for phosphor-converted white LEDs
(2011-07-04)
Kuo, Hao-Chung
;
Hung, Cheng-Wei
;
Chen, Hsin-Chu
;
Chen, Kuo-Ju
;
Wang, Chao-Hsun
High efficiency white light-emitting diodes with superior color-mixing have been investigated. It is suggested that the patterned remote phosphor structure could improve the uniformity of angular-dependent correlated color temperature (CCT) and achieve high chromatic stability in wider operating current range, as compared to the conventional remote phosphor coating structure. In this experiment, we employed a pulse spray coating method to place the patterned phosphor on the package and to leave a window region. The window area, a clear space without coating of the phosphor not only increases the extraction efficiency of blue rays at large angle, but also improves the stability of angular-dependent CCT. Moreover, the CCT deviation could be reduced from 1320 K to 266 K by this patterned remote phosphor method, and the stray blue/yellow light within the package can be effectively reduced and controlled. The design was verified both experimentally and theoretically. (C) 2011 Optical Society of America
Cluster LEDs mixing optimization by lens design techniques
(2011-07-04)
Chien, Ming-Chin
;
Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
;
Department of Photonics
This paper presents a methodology analogous to a general lens design rule to optimize step-by-step the spectral power distribution of a white-light LED cluster with the highest possible color rendering and efficiency in a defined range of color temperatures. By examining a platform composed of four single-color LEDs and a phosphor-converted cool-white (CW) LED, we successfully validate the proposed algorithm and suggest the optimal operation range (correlated color temperature = 2600-8500 K) accompanied by a high color quality scale (CQS > 80 points) as well as high luminous efficiency (97% of cluster's theoretical maximum value). (C) 2011 Optical Society of America
UV Photolysis of ClOOCl and the Ozone Hole
(2011-07-04)
Lin, Jim J.
;
Chen, Andrew F.
;
Lee, Yuan T.
;
應用化學系
;
Department of Applied Chemistry
The photochemistry of the ClO dimer (ClOOCl) plays a central role in the catalytic destruction of polar stratospheric ozone. In spite of decades of intense investigations, some of its laboratory photochemical data had not reached the desired accuracy to allow a reliable simulation of the stratospheric ozone loss until recently. Inevitable impurities in ClOOCl samples have obstructed conventional measurements. In particular, an absorption measurement of ClOOCl in 2007, which gave much lower cross sections than previous studies, implied that the formation of the ozone hole cannot be explained with cur-rent chemical models. Scientists have wondered whether the model is insufficient or the data is erroneous. Efforts aiming to resolve this controversy are reviewed in this paper, which emphasizes newly developed experiments to determine two critical photochemical properties of ClOOCl-its absorption cross section and product branching ratio-including the first reported product branching ratio at 351.8 nm photolysis.
Surface-emitting laser device
(2011-07-05)
Chen Shih-Wei
;
Lu Tien-Chang
;
Kuo Hao-Chung
;
Wang Shing-Chung
A surface-emitting laser device includes: a substrate; a low refractive index layer with a refractive index nL and disposed on the substrate; a light emitting layered structure with a refractive index nH, where nH>nL, the light emitting layered structure being formed on the low refractive index layer and having first and second semiconductor layers and a multi-quantum well (MQW) disposed between the first and second semiconductor layers and capable of generating photons having a wavelength λ0; and a two-dimensional photonic crystal (2DPC) formed in the light emitting layered structure and having optical nanostructures arranged into a periodic pattern with a lattice constant a. The nanostructures extend from the first semiconductor layer through the MQW. The 2DPC has a normalized frequency, which is defined as a/λ0, ranging from 0.25 to 0.70.
交大e-News第097期
(2011-07-05)
Secretariat
;
國立交通大學秘書室
Organic-semiconductor-based infrared receiving device
(2011-07-05)
Meng Hsin-Fei
;
Horng Sheng-Fu
;
Yang Chia-Ming
An organic-semiconductor-based infrared receiving device comprises an electrode layer having a positive layer and a negative layer to form an electric field, and a transport layer located between the positive and negative layers and having a first and a second predetermined material combined in a predetermined ratio. The energy of infrared light from a light source is received at an interface between the first and second materials. The thickness of the transport layer can be increased to enhance the light absorbance in the infrared light range to form electron-hole pairs, which are then parted to form a plurality of electrons and holes driven by the electric field to move to the negative layer and the positive layer, respectively, so that a predetermined photocurrent is generated.
Exploring the selective constraint on the sizes of insertions and deletions in 5 ' untranslated regions in mammals
(2011-07-05)
Chen, Chun-Hsi
;
Liao, Ben-Yang
;
Chen, Feng-Chi
;
生物科技學系
;
Department of Biological Science and Technology
Background: Small insertions and deletions ("indels" with size <= 100 bp) whose lengths are not multiples of three (non-3n) are strongly constrained and depleted in protein-coding sequences. Such a constraint has never been reported in noncoding genomic regions. In 5' untranslated regions (5' UTRs) in mammalian genomes, upstream start codons (uAUGs) and upstream open reading frames (uORFs) can regulate protein translation. The presence of non-3n indels in uORFs can potentially disrupt the functions of these regulatory elements. We thus hypothesize that natural selection disfavors non-3n indels in 5' UTRs when these regulatory elements are present. Results: We design the Indel Selection Index to measure the selective constraint on non-3n indels in 5' UTRs. The index controls for the genomic compositions of the analyzed 5' UTRs and measures the probability of non-3n indel depletion downstream of uAUGs. By comparing the experimentally supported transcripts of human-mouse orthologous genes, we demonstrate that non-3n indels downstream of two types of uAUGs (alternative translation initiation sites and the uAUGs of coding sequence-overlapping uORFs) are underrepresented. The results hold well regardless of differences in alignment tool, gene structures between human and mouse, or the criteria in selecting alternatively spliced isoforms used for the analysis. Conclusions: To our knowledge, this is the first study to demonstrate selective constraints on non-3n indels in 5' UTRs. Such constraints may be associated with the regulatory functions of uAUGs/uORFs in translational regulation or the generation of protein isoforms. Our study thus brings a new perspective to the evolution of 5' UTRs in mammals.
Calculation of spontaneous emission from a V-type three-level atom in photonic crystals using fractional calculus
(2011-07-05)
Huang, Chih-Hsien
;
Wu, Jing-Nuo
;
Li, Yen-Yin
;
Cheng, Szu-Cheng
;
Hsieh, Wen-Feng
Fractional time derivative, an abstract mathematical operator of fractional calculus, is used to describe the real optical system of a V-type three-level atom embedded in a photonic crystal. A fractional kinetic equation governing the dynamics of the spontaneous emission from this optical system is obtained as a fractional Langevin equation. Solving this fractional kinetic equation by fractional calculus leads to the analytical solutions expressed in terms of fractional exponential functions. The accuracy of the obtained solutions is verified through reducing the system into the special cases whose results are consistent with the experimental observation. With accurate physical results and avoiding the complex integration for solving this optical system, we propose fractional calculus with fractional time derivative as a better mathematical method to study spontaneous emission dynamics from the optical system with non-Markovian dynamics.
Process for treating nitrogenous wastewater with simultaneous autotrophic denitrification, hetertrophic denitrification and COD removal
(2011-07-05)
Lee Der-Ming
;
Chiang Ming-Kuei
;
Chen Chin-Te
;
Sung Keng-Chuan
;
Lin Jih-Gaw
A process for treating nitrogenous wastewater contains an autotrophic denitrification reaction, a heterotrophic denitrification reaction and a COD removal reaction simultaneously and mixedly taking place in a single reactor. The nitrification reaction is caused by nitrifying bacteria, in which ammonium is oxidized into nitrite. The autotrophic denitrification reaction is caused by autotrophic denitrifying bacteria, in which ammonium used as electron donor and nitrite used as electron acceptor are converted into nitrogen gas and nitrate. The heterotrophic denitrification reaction is caused by heterotrophic denitrifying bacteria, in which nitrate and COD are consumed. It is not necessary to build two separate reactors for aerobic nitrification and anaerobic denitrification, thereby effectively reducing the fabrication and operation cost.
Fiber grating sensor
(2011-07-05)
Huang An-Bin
;
Kao Sheng-Chiang
A fiber grating sensor including an elastic circular plate and one or two FBG'ss attached to the bottom surface of the elastic circular plate. Two ends of the FBG are connected to an optic fiber for signal transmission. The fiber grating sensor readouts are independent of temperature variation. The fiber grating sensor mechanism according to the present invention may be applied in a variety of sensors such as gauge pressure transducer, differential pressure transducer, load cell and displacement transducer with a distributive design, and for various purposes.
High load driving device
(2011-07-05)
Chuang Ching-Te
;
Lu Chien-Yu
A high load driving device is disclosed. The driving device comprises an inverter receiving a digital voltage. The inverter reverses the digital voltage, and then sends out it. The output terminal of the inverter is coupled to a capacitor, a first P-type field-effect transistor (FET), a second P-type FET, a first N-type FET, and a third N-type FET. A push-up circuit is composed of these transistors and a second N-type FET and coupled to a P-type push-up FET. A load is coupled to a high voltage through the P-type push-up FET. When the digital voltage rises from a low level to a high level, the push-up circuit utilizes the original voltage drop of the capacitor to control the P-type push-up FET, whereby the gate voltage of the P-type push-up FET is at a low stabilization voltage that is lower than the ground potential. Then, the load is driven rapidly.
最佳空間-時間-頻率區塊碼之搜尋方法及其多輸入多輸出之多頻帶超寬頻系統
(2011-07-11)
王蒞君
;
劉維正
一種最佳空間－時間－頻率(space－time－frequency，STF)區塊碼之搜尋方法能夠以較少的運算量，有系統地搜尋出最佳之空間－時間－頻率區塊碼。同時亦揭露一種多輸入多輸出之多頻帶超寬頻系統，其以上述之最佳STF區塊碼進行編碼，以使位元錯誤率達到最小。
16-Hydroxycleroda-3,13-dien-15,16-olide deregulates PI3K and Aurora B activities that involve in cancer cell apoptosis
(2011-07-11)
Lin, Yi-Hsiung
;
Lee, Chien-Chih
;
Chan, Wen-Li
;
Chang, Wen-Hsin
;
Wu, Yang-Chang
The PI3K-AKT pathway and Aurora kinase play essential roles in such cellular processes as cell survival, angiogenesis, and differentiation, and are usually expressed at maximum levels during cancer cell proliferation. The present study investigated the effect of the natural compound, 16-hydroxycleroda-3,13-dien-15,16-olide (PL3), on regulating the PI3K-AKT pathway and Aurora B, which led to cancer cell apoptosis. PL3 acts as a PI3K inhibitor by influencing cell survival, signaling transduction, and cell cycle progression. It was observed that PL3 targeted and induced dephosphorylation of the PI3K pathway, degradation of Aurora B and mitotic-related gene expressions, and sequentially shut down the cell cycle. This eventually resulted in cell death. As Aurora B was downregulated, spindle dysfunction and destruction of the G(2)/M phase checkpoint resulted in DNA-damaged cells undergoing apoptosis. Moreover. PL3 also resensitized T31 5I-mutated Bcr-ABL(+) BA/F3 cells to improve the cytotoxicity of Imatinib in Imatinib-resistant cell line. Taken together, PL3 can perturb the PI3K-AKT pathway and Aurora B resulting in gene silencing and cell cycle disturbance. It was demonstrated that PL3 acted like a novel small-molecule PI3K modulator, thereby potentially contributing to cancer chemotherapy and combination medication. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
無線網路中執行換手程序的裝置與方法
(2011-07-11)
林一平
;
許世芬
一種無線網路中執行換手程序的裝置與方法。此裝置包含一處理機執行一識別碼檢查機制，當無線網路用戶欲從一來源存取點移動至一目的地存取點時，無線網路用戶傳送一認證要求訊息至目的地存取點，識別碼檢查機制將認證要求訊息內的一R0金鑰持有者識別碼向此目的地存取點的一R0KH表查詢，並決定出正確換手程序的一設定參數，依此讓該無線網路用戶執行換手程序。目的地存取點之R0KH表是由在此目的地存取點網域範圍下可被其存取之所有R0金鑰持有者的識別碼來組成。
Optical properties of self assembled GaN polarity inversion domain boundary
(2011-07-11)
Liu, M. -C.
;
Cheng, Y. -J.
;
Chang, J. -R.
;
Hsu, S. -C.
;
Chang, C. -Y.
We report the fabrication of GaN lateral polarity inversion heterostructure with self assembled crystalline inversion domain boundaries (IDBs). The sample was fabricated by two step molecular-beam epitaxy (MBE) with microlithography patterning in between to define IDBs. Despite the use of circular pattern, hexagonal crystalline IDBs were self assembled from the circular pattern during the second MBE growth. Both cathodoluminescent (CL) and photoluminescent (PL) measurements show a significant enhanced emission at IDBs and in particular at hexagonal corners. The ability to fabricate self assembled crystalline IDBs and its enhanced emission property can be useful in optoelectronic applications. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3610449]
Investigating the degradation behavior caused by charge trapping effect under DC and AC gate-bias stress for InGaZnO thin film transistor
(2011-07-11)
Chen, Te-Chih
;
Chang, Ting-Chang
;
Hsieh, Tien-Yu
;
Lu, Wei-Siang
;
Jian, Fu-Yen
This letter investigates the degradation mechanism of amorphous indium-gallium-zinc oxide thin-film transistors under gate-bias stress. The larger V(t) shift under positive AC gate-bias stress when compared to DC operation indicates that an extra electron trapping mechanism occurs during rising/falling time during the AC pulse period. In contrast, the degradation behavior under illuminated negative gate-bias stress exhibits the opposite degradation tendency. Since electron and hole trapping are the dominant degradation mechanisms under positive and illuminated negative gate-bias stress, respectively, the different degradation tendencies under AC/DC operation can be attributed to the different trapping efficiency of electrons and holes. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3609873]