Browsing by Issue Date, starting with "2009-03-02"

Now showing 1 - 20 of 51256

Physical properties of amorphous InGaZnO(4) films doped with Mn
(2009-03-02)
Liu, Shiu-Jen
;
Fang, Hau-Wei
;
Su, Shih-Hao
;
Li, Chia-Hung
;
Cherng, Jyh-Shiarn
Amorphous InGaZnO(4) (a-IGZO) films doped with various concentrations of Mn have been fabricated by using pulsed-laser deposition technique. Optical, electrical, and magnetic properties of the prepared Mn-doped a-IGZO films were investigated. The resistivity, carrier concentration, and carrier mobility of the a-IGZO films were found to be, respectively, increased, decreased, and enhanced by Mn doping. Moreover, the optical transmission is slightly increased in the visible range and the optical band gaps are not affected in the Mn-doped films. Room-temperature ferromagnetism has been observed in the field-dependent magnetization measurements.
Physical properties of amorphous InGaZnO4 films doped with Mn
(2009-03-02)
Liu, Shiu-Jen
;
Fang, Hau-Wei
;
Su, Shih-Hao
;
Li, Chia-Hung
;
Cherng, Jyh-Shiarn
Amorphous InGaZnO4 (a-IGZO) films doped with various concentrations of Mn have been fabricated by using pulsed-laser deposition technique. Optical, electrical, and magnetic properties of the prepared Mn-doped a-IGZO films were investigated. The resistivity, carrier concentration, and carrier mobility of the a-IGZO films were found to be, respectively, increased, decreased, and enhanced by Mn doping. Moreover, the optical transmission is slightly increased in the visible range and the optical band gaps are not affected in the Mn-doped films. Room-temperature ferromagnetism has been observed in the field-dependent magnetization measurements.
A lighting mechanism for flat electron emission lamp
(2009-03-02)
Li, Jung-Yu
;
Chen, Shih-Pu
;
Li, Chia-Hung
;
Lin, Yi-Ping
;
Chou, Yen-I
We propose a lighting mechanism for generating uniform planar light. The device integrates electron beams induced by gas discharge with cathodoluminescence at the anode, where the spectra of the emitted light depend entirely on the phosphor materials coated on the anode. Consequently, ultraviolet is not required and the usage of mercury can be avoided. In addition, the features of double-side lighting, transparency, and gray-scale images indicate that the flat electron emission lamp might become potential candidate for the next generation green lighting source.
Thermomigration in Pb-free SnAg solder joint under alternating current stressing
(2009-03-02)
Hsiao, Hsiang-Yao
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Lead-free solders have been adopted by the microelectronics industry. However, their thermomigration behaviors are unclear. Thermomigration in eutectic SnAg3.5 solder joints was investigated using an alternating current (ac) of 0.57 A at 100 degrees C. The ac eliminates the electromigration effect and creates a thermal gradient of 2829 degrees C/cm, facilitating the study of thermomigration. Arrays of tiny markers fabricated by a focused ion beam are employed to measure the thermomigration rate. It is found that Sn atoms migrated toward the hot end. The thermomigration flux and molar heat of transport are measured to be 5.0x10(12) atoms/cm(2) and 1.36 kJ/mole, respectively.
2009 交大建築展
(2009-03-03)
Arts Center
;
Graduate Institute of Architecture
;
藝文中心
;
建築研究所
展覽時間：2009.03.03(二)~2009.03.22(日) 開幕茶會：2009.03.03(二)中午 12:00 創作者導覽：2009.03.03(二)下午1:30~2:30 展場：交大藝文空間展場開放時間：星期一~星期五 10:00~19:00 星期六~星期日 10:00~17:00 洽詢電話：(03)571-2121 分機52666 展場地址：新竹市大學路1001號浩然圖書館 B1 主辦單位：交通大學藝文中心、交通大學建築研究所贊助單位：交大校友會、財團法人交大思源基金會
Tandem One-Pot Acetalation-Acetylation for Direct Access to Differentially Protected Thioglycosides and O-Glycosides with p-Toluenesulfonic Acid
(2009-03-03)
Mong, Kwok-Kong Tony
;
Chao, Chin-Sheng
;
Chen, Min-Chun
;
Lin, Chun-Wei
;
應用化學系
A new tandem one-pot acetalation-acetylation procedure is reported which streamlines routine protecting-group manipulation of carbohydrate molecules in production of differentially protected 0- and thioglycosides. This new procedure eliminates the use of highly toxic pyridine, and p-toluenesulfonic acid is employed as catalyst for acetalation and acetylation. Synthetic utility of the new procedure is demonstrated in the expeditious preparation of differentially protected glycosides from a wide variety of carbohydrate substrates including unprotected O-glycosides, thioglycosides, and N-acetyl neuraminic acid ester.
Thermostability of the N-Terminal RNA-Binding Domain of the SARS-CoV Nucleocapsid Protein: Experiments and Numerical Simulations
(2009-03-04)
Fang, Huey-Jen
;
Chen, Yong-Zhong
;
Li, Mai Suan
;
Wu, Ming-Chya
;
Chang, Chun-Ling
Differential scanning calorimetry, circular dichroism spectroscopy, nuclear magnetic resonance spectroscopy, and numerical simulations were used to study the thermostability of the N-terminal RNA-binding domain (RBD) of the SARSCoV nucleocapsid protein. The transition temperature of the RBD in a mixing buffer, composed of glycine, sodium acetate, and sodium phosphate with 100 mM sodium chloride, at pH 6.8, determined by differential scanning calorimetry and circular dichroism, is 48.74 degrees C. Experimental results showed that the thermal-induced unfolding-folding transition of the RBD follows a two-state model with a reversibility >90%. Using a simple Go-like model and Langevin dynamics we have shown that, in agreement with our experiments, the folding of the RBD is two-state. Theoretical estimates of thermodynamic quantities are in reasonable agreement with the experiments. Folding and thermal unfolding pathways of the RBD also were experimentally and numerically studied in detail. It was shown that the strand 01 from the N-terminal folds last and unfolds first, while the remaining beta-strands fold/unfold cooperatively.
A nanoporous optically transparent CdS-pHEMA hybrid with high optical sensing capability to dielectric liquids
(2009-03-04)
Liao, Hung-Chou
;
Liu, Yen-Yu
;
Chen, San-Yuan
;
Liu, Dean-Mo
;
材料科學與工程學系
A hydrogel-based functional hybrid with highly uniformly dispersed nanoparticulate CdS semiconductors is proposed. The hybrid is synthesized using an in situ polymerization following an in situ chemical reduction, where the resulting particle size and the distribution of CdS nanocrystals (NCs) can be narrowly manipulated. The hybrids, containing a relatively small amount of the CdS NCs, exhibit a pronounced photoluminescence spectrum shift when in contact with a number of dielectric liquids and such a pronounced dielectric-confinement effect has been experimentally verified and modeled in this study. The sensing capability of the hybrids with respect to dielectric liquids or molecules can be optically characterized and varied depending upon the intensity of the dielectric environment surrounding the hybrids. This work suggests that the transparent, nanoporous CdS-pHEMA hybrids can be used as highly efficient optical sensing materials.
On the calculation of the dissociation rate constant of the water dimer by the ab initio anharmonic RRKM theory
(2009-03-05)
Yao, L.
;
He, R. X.
;
Mebel, A. M.
;
Lin, S. H.
;
應用化學系
The dissociation rate constant of the water dimer was calculated by using the method proposed by Yao and Lin (YL method). The dividing surface method and RRKM theory are used to calculate the pseudo transition state and the rate constant, respectively. For the canonical case at temperature range of 243-1000 K and for the microcanonical system at total energy 1411-4000 cm(1), the anharmonic rate constant, around 10(9)-10(11) s(1), is close to the experimental prediction. The present results indicate that the anharmonic effect should be included and YL method is suitable for calculating dissociation rate constants of such small flexible water cluster. (C) 2009 Elsevier B. V. All rights reserved.
Self-Assembled Fernlike Microstructures of Polyhedral Oligomeric Silsesquioxane/Gold Nanoparticle Hybrids
(2009-03-05)
Lu, Chu-Hua
;
Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Chang, Feng-Chih
;
應用化學系
We have used a thiol-functionalized polyhedral oligomeric silsesquioxane (SH-POSS) as a protective group for the preparation of POSS-protected gold nanoparticles (POSS-Au NPs). The organic/inorganic hybrid SH-POSS NPs exhibited an interesting platelike morphology arising from steric hindrance between the isobutyl groups of SH-POSS. An XRD study of the SH-POSS crystal revealed the relatively large interstice (1.64 nm lattice constant a > 1.3 nm diameter SH-POSS) on the basal plane of the unit cell, which resulted in a platelike morphology having lateral dimensions on the order of a few micrometers and thicknesses of a few hundred nanometers. In addition to behaving as a stabilizer for the preparation of Au NPs, an excess of SH-POSS colloids led to the formation of a crystalline template that incorporated the POSS-Au hybrid NPs on its surface, providing a unique fernlike microstructure. After removal of the POSS template (through sublimation and decomposition to a silica char) at 350 degrees C in air for I h, nanosized Au islands having diameters of 50-100 nm and thicknesses of 2-20 nm were sintered onto the substrate. As a result, SH-POSS is an excellent protective group for the preparation of Au NPs of high stability in the powder state. In addition, we suspect that SH-POSS crystals could be used to disperse Au NPs onto substrates for a wide range of applications (e.g., Au catalysts).
交大e-News第043期
(2009-03-05)
Secretariat
;
國立交通大學秘書室
Adsorption Configurations and Decomposition Pathways of Boric Acid on TiO(2) Rutile (110) Surface: A Computational Study
(2009-03-05)
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
We have investigated the adsorption and reactions of the monomer and dimer of B(OH)(3) on TiO(2) rutile (110) surface by first-principles calculations. The most stable adsorption structure for B(OH)(3) On the surface is a molecular monodentate configuration, with one hydrogen bonded to a neighboring surface bridging oxygen with an adsorption energy of 20.1 kcal/mol. The adsorbed B(OH)(3) molecule can dissociate into the bidentate adsorption configuration, Ti-OB(OH)O-Ti(a), in which the -OB(OH)O- moiety binds to the surface through two Ti-O bonds with the two dissociated H atoms on neighboring bridged surface oxygen atoms following stepwise H-migration. Notably, the adsorption energy for Ti-OB(OH)O-Ti(a) with 2 H on two O(b) surface atoms is 134.6 kcal/mol. In the case of dimer there are two identical molecules similar to monodentate configuration of B(OH)(3) adsorbed on two 5-fold-coordinated Ti atoms of the surface with an adsorption energy of 37.9 kcal/mol. Following intramolecular dehydration and successive migrations of protons from two OH groups to neighboring Ob sites, very stable Ti-OB(OH)OB(OH)O-Ti adsorbate can be readily formed with 141.1 kcal/mol binding energy. Both Ti-OB(OH)O-Ti(a) and Ti-OB(OH)OB(OH)O-Ti(a) adsorbates can be ideally employed as linkers between semiconductor quantum dots such as metal nitride or selenides and TiO(2) nanoparticles by pretreatment of nanoparticle films with B(OH)(3). A similar study on the adsorption and reactions of B(OH)(3) on anatase (101) surface has been recently reported. The most noticeable difference is that B(OH)(3) and its dimer on the rutile surface have slightly higher binding energies than those on the anatase surface and that the rutile surface is more effective for proton migration from the acid to the surface O-atom.
Adsorption Configurations and Decomposition Pathways of Boric Acid on TiO2 Rutile (110) Surface: A Computational Study
(2009-03-05)
Raghunath, P.
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
We have investigated the adsorption and reactions of the monomer and dimer of B(OH)(3) on TiO2 rutile (110) surface by first-principles calculations. The most stable adsorption structure for B(OH)(3) On the surface is a molecular monodentate configuration, with one hydrogen bonded to a neighboring surface bridging oxygen with an adsorption energy of 20.1 kcal/mol. The adsorbed B(OH)(3) molecule can dissociate into the bidentate adsorption configuration, Ti-OB(OH)O-Ti(a), in which the -OB(OH)O- moiety binds to the surface through two Ti-O bonds with the two dissociated H atoms on neighboring bridged surface oxygen atoms following stepwise H-migration. Notably, the adsorption energy for Ti-OB(OH)O-Ti(a) with 2 H on two O-b surface atoms is 134.6 kcal/mol. In the case of dimer there are two identical molecules similar to monodentate configuration of B(OH)(3) adsorbed on two 5-fold-coordinated Ti atoms of the surface with an adsorption energy of 37.9 kcal/mol. Following intramolecular dehydration and successive migrations of protons from two OH groups to neighboring Ob sites, very stable Ti-OB(OH)OB(OH)O-Ti adsorbate can be readily formed with 141.1 kcal/mol binding energy. Both Ti-OB(OH)O-Ti(a) and Ti-OB(OH)OB(OH)O-Ti(a) adsorbates can be ideally employed as linkers between semiconductor quantum dots such as metal nitride or selenides and TiO2 nanoparticles by pretreatment of nanoparticle films with B(OH)(3). A similar study on the adsorption and reactions of B(OH)(3) on anatase (101) surface has been recently reported. The most noticeable difference is that B(OH)(3) and its dimer on the rutile surface have slightly higher binding energies than those on the anatase surface and that the rutile surface is more effective for proton migration from the acid to the surface O-atom.
alpha-MoO(3) nanocrystals of controlled size on a glass substrate
(2009-03-05)
Wu, Ming-Cheng
;
Lee, Chi-Shen
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
A procedure to grow alpha-MoO(3) nanocrystals of rod and belt forms under mild conditions involved deposition onto a glass substrate via vapor transport with a water-soluble precursor. Scanning electron and transmission electron microscopic studies, selected-area electron diffraction and powder X-ray analyses indicate that these alpha-MoO(3) nanocrystals exhibit rod or belt forms that grow along [0 0 1] and became vertically aligned on the glass substrate. Such deposition is effective to form thin films of controllable size and density of coverage on varying the precursor concentration and the duration of deposition. (C) 2008 Published by Elsevier Ltd.
Interfacial reaction between Sn-1Ag-0.5Cu(-Co) solder and Cu substrate with Au/Ni surface finish during reflow reaction
(2009-03-05)
Lin, K. S.
;
Huang, H. Y.
;
Chou, C. P.
;
機械工程學系
;
Department of Mechanical Engineering
In order to clarify the effect of the addition of Co to SAC105 solder, the reaction between solder and Au/Ni surface finish has been investigated, and the joint strength was also evaluated by a ball shear test. After soldering, the interfacial reaction layer in the SAC105 Co solder contained Co, and the chemical composition of intermetallic compounds (IMCs) were identified as (Cu,Ni,Co)(6)Sn(5) and (Ni,Cu,Co)(3)Sn(4) by energy-dispersive X-ray spectrometer (EDX), which significantly differed from that of SAC105 solder. After multiple reflows, the formation rate of the (Cu,Ni,Co)(6)Sn(5) IMC for the Co-added solder slow compared with that of (Cu,Ni)(6)Sn(5) IMC for SAC105 solder. Experimental results clearly indicate that adding small amounts (0.05 wt.%) of Co to SAC105 solder strongly affected the formation of the IMC at the interface. Furthermore, ball shear test results demonstrate that the SAC105 and SAC105 Co solder joints have good joint reliability. (C) 2008 Elsevier B.V. All rights reserved.
alpha-MoO3 nanocrystals of controlled size on a glass substrate
(2009-03-05)
Wu, Ming-Cheng
;
Lee, Chi-Shen
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
A procedure to grow alpha-MoO3 nanocrystals of rod and belt forms under mild conditions involved deposition onto a glass substrate via vapor transport with a water-soluble precursor. Scanning electron and transmission electron microscopic studies, selected-area electron diffraction and powder X-ray analyses indicate that these alpha-MoO3 nanocrystals exhibit rod or belt forms that grow along [0 0 1] and became vertically aligned on the glass substrate. Such deposition is effective to form thin films of controllable size and density of coverage on varying the precursor concentration and the duration of deposition. (C) 2008 Published by Elsevier Ltd.
Etching method for nitride semiconductor
(2009-03-05)
Lee, Wei-I
;
Huang, Hsin-Hsiung
;
Zeng, Hung-Yu
The invention discloses etching method for the nitride semiconductor. Firstly dielectric layer is formed on gallium nitride. The line pattern or dot pattern is formed on the dielectric layer by using the exposure, development, and etching processes. The dielectric layer is used as the mask for the epitaxial lateral overgrowth of follow-up gallium nitride layer. The thick gallium nitride film is grown on the dielectric layer. Then the wet etching process is used to remove the dielectric layer, and the thick gallium nitride film on the dielectric layer is etched to form the specific shape as required.
Control of the spatial emission structure of broad-area vertical-cavity surface-emitting lasers by feedback
(2009-03-07)
Schulz-Ruhtenberg, M.
;
Tanguy, Y.
;
Huang, K. F.
;
Jaeger, R.
;
Ackemann, T.
The wave number of transverse spatial structures in broad-area vertical-cavity surface-emitting lasers (VCSELs) is controlled via frequency-selective feedback from an external self-imaging cavity in a broad range of wave numbers and emission frequencies. The selected states follow the dispersion curves of the free-running laser. A control range of about 2.5 mu m(-1) in spatial frequency space and 2.5 nm in emission wavelength was obtained for square VCSELs and of about 3 mu m(-1) and 8 nm for circular VCSELs having a different dispersion curve. By spatial filtering in Fourier space, the shape of the structures can also be controlled to some extent. It is argued that the feedback techniques are useful to 'probe' emission states of the free-running laser.
Differential Sensing of Serine and Tyrosine with Aligned CdS Nanowire Arrays Based on pH-Dependent Photoluminescence Behavior
(2009-03-09)
Lin, Yi-Feng
;
Hsu, Yung-Jung
;
Cheng, Wei-Yun
;
Lu, Shih-Yuan
;
材料科學與工程學系
The differential sensing of tyrosine and serine is achieved with well-aligned CdS nanowire arrays by exploring the pH-dependent photoluminescence behavior of the nanowire arrays toward exposure to the two amino acid solutions. The contrasting trend in photoluminescence (PL) intensity with respect to variations in analyte concentration observed at pH 11 served as the check point for the present differential sensing. The application format of the nanowire array is better suited for further sensing device assembly than that of nanocrystal suspensions.
Cobalt nanodots formed by annealing the CoSiO layer for the application of the nonvolatile memory
(2009-03-09)
Hu, Chih-Wei
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Shueh, Pei-Kun
;
Lin, Chao-Cheng
Co nanodot memory devices formed by oxidation processes were studied. Transmission electron microscopy and x-ray photoelectron spectroscopy analyses showed that overoxidation of the cobalt and silicon degraded the charge-storage ability seriously. However, a precapped oxide can mildly oxidize the CoSi(2) film to protect the overoxidation to occur. In addition, an oxygen-incorporated CoSi(2) film is proposed to improve the oxidation process further. Through incorporating the limited oxygen during sputtering process, the Co nanodot memory device obtains a larger memory window. Also, the reliability characteristic of the Co nanodot memory device formed by annealing the oxygen-incorporated CoSi(2) film has been demonstrated.