Browsing by Issue Date, starting with "2003-06-06"

Now showing 1 - 20 of 72599

管管作品兩首
(2003-06-06)
管管
管管作品兩首
(2003-06-06)
管管
管管作品兩首
(2003-06-06)
管管
管管作品兩首
(2003-06-06)
管管
Mechanism of posttranslational regulation of phenol sulfotransferase: Expression of two enzyme forms through redox modification and nucleotide binding
(2003-06-10)
Su, TM
;
Yang, YS
;
生物科技學系
;
Department of Biological Science and Technology
Sulfotransferase catalyzes sulfuryl group transfer between a nucleotide and a variety of nucleophiles that may be sugar, protein, xenobiotics, and other small molecules. Nucleotides may serve as cosubstrate, cofactor, inhibitor, or regulator in an enzyme catalyzed sulfuryl group transfer reaction. We are trying to understand how nucleotide regulates the activity of phenol sulfotransferase (PST) through the expression of two enzyme forms. The homogeneous rat recombinant PST was obtained from Escherichia coli, and the nucleotide copurified was examined. The nucleotide was completely removed from inactive PST in high salt and oxidative condition. Total enzyme activity was recovered following incubation in reductive environment. Many nucleotides are known to tightly bind to PST but only one nucleotide, 3'-phosphoadenosine 5'-phosphate (PAP), was identified to combine with PST by ion-pair RP-HPLC, UV-visible spectra, P-31 NMR, and ESI-MS and MS-MS spectrometry. In addition to the presence or absence of PAP, oxidation following reduction of PST was required to completely interconvert the two forms of PST. According to the experimental results, a mechanism for the formation of the two enzyme forms was proposed.
Dependence of energy gap on magnetic field in semiconductor nano-scale quantum rings
(2003-06-10)
Li, YM
;
Lu, HM
;
Voskoboynikov, O
;
Lee, CP
;
Sze, SM
We study the electron and hole energy states for a complete three-dimensional (3D) model of semiconductor nanoscale quantum rings in an external magnetic field. In this study, the model formulation includes: (i) the position dependent effective mass Hamiltonian in non-parabolic approximation for electrons, (ii) the position dependent effective mass Hamiltonian in parabolic approximation for holes, (iii) the finite hard wall confinement potential, and (iv) the Ben Daniel-Duke boundary conditions. To solve this 3D non-linear problem, we apply the non-linear iterative method to obtain self-consistent solutions. We find a non-periodical oscillation of the energy band gap between the lowest electron and hole states as a function of external magnetic fields. The result is useful in describing magneto-optical properties of the nano-scale quantum rings. (C) 2003 Elsevier Science B.V. All rights reserved.
金氧半場效電晶體之結構
(2003-06-11)
崔秉鉞
;
黃誌鋒
本發明提供一種可降低源極蕭基位障(Schottky Barrier)載子注入阻抗(Carrier Injection Resistance)的金氧半場效電晶體(MOSFET)之結構及其方法。該結構至少包含一矽覆絕緣(SOI)基板為該結構之基材，一金屬氧化物半導體(MOS)形成於該矽覆絕緣基板之上，以及一金屬矽化物層(Metal-Silicide Layer)。其中該矽覆絕緣基板具有一基底(Substrate)，一絕緣層 (Insulation Layer)位於該基底之上，以及一矽晶層 (Silicon Layer)位於該絕緣層之上；藉由沉積一金屬層(Metal Layer)於該半導體上，利用金屬自行對準矽化物製程與該矽晶層結合後形成該金屬矽化物層，再利用離子植入金屬矽化物或金屬層的製程 (Implant-to-silicide or implant-to-metal) 形成源極與汲極高濃度區以降低源極蕭基位障(Schottky Barrier)載子注入阻抗(Carrier Injection Resistance)。
管管作品二十七首
(2003-06-15)
管管
Flower-like distributed self-organized Ge dots on patterned Si (001) substrates
(2003-06-15)
Lee, HM
;
Yang, TH
;
Luo, GL
;
Chang, EY
;
材料科學與工程學系
Self-organized Ge dots were obtained utilizing ultra high vacuum chemical molecular epitaxial growth of Ge on electron beam lithographically patterned Si (001) substrates. The dimensions of these etched Si mesa are 65/23/200 nm in diameter/height/period. The sizes and arrangement of the Ge dots were characterized by scanning electron microscopy and atomic force microscopy. The Ge dots have an average base width of 10 nm and the size is quite uniform. Due to the energetically favorable sites, the Ge dots tend to form homocentrically along the Si mesa edge, and their distribution is flower-like. [DOI: 10.1143/JJAP.42.L718].
管管作品二十七首
(2003-06-15)
管管
Formation of interfacial layer during reactive sputtering of hafnium oxide
(2003-06-15)
Tsui, BY
;
Chang, HW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Hafnium oxide is one of the most promising high dielectric constant materials to replace silicon dioxide as the gate dielectric. To take the advantages of high dielectric constant of HfO2 thoroughly, the relatively low dielectric constant interfacial layer must be controlled carefully. In this work, the formation of an interfacial SiO2 layer at the HfO2/Si interface was studied comprehensively. It is observed that during reactive sputtering deposition of the HfO2 layer, a very thick interfacial SiO2 layer, thicker than 3 nm, would be grown. O-radical signals, instead of O-2-radicl signals, are detected in the sputtering chamber. An O-radical enhanced oxidation model is proposed to explain such an unusual thick SiO2 layer. The adoption of a two-step deposition method, the thickness of interfacial SiO2 layer can be reduced only if the bottom Hf layer is thicker than 5 nm. However, the reduction of effective oxide thickness would be limited. Reoxidation of Hf film sounds a better choice. A 1.0-1.5-nm-thick interfacial SiO2 layer is still observed. This implies that the traced oxygen in the sputtering chamber plays a critical role on the formation of the interfacial layer. It is thus concluded that reactive sputtering is not a suitable method to prepare a HfO2 layer with a negligible interfacial SiO2 layer. Reoxidation of Hf film is a better choice, but the oxygen content in the sputtering chamber must be well controlled. (C) 2003 American Institute of Physics.
管管作品二十七首
(2003-06-15)
管管
管管作品二十七首
(2003-06-15)
管管
管管作品二十七首
(2003-06-15)
管管
管管作品二十七首
(2003-06-15)
管管
Ring embedding in faulty pancake graphs
(2003-06-15)
Hung, CN
;
Hsu, HC
;
Liang, KY
;
Hsu, LH
;
資訊工程學系
In this paper, we consider the fault hamiltonicity and the fault hamiltonian connectivity of the pancake graph P-n. Assume that F subset of or equal to V(P-n) boolean OR E(P-n). For n greater than or equal to 4, we prove that P-n - F is hamiltonian if F less than or equal to (n - 3) and P-n - F is hamiltonian connected if F less than or equal to (n - 4). Moreover, all the bounds are optimal. (C) 2003 Elsevier Science B.V. All rights reserved.
管管作品二十七首
(2003-06-15)
管管
管管作品二十七首
(2003-06-15)
管管
管管作品二十七首
(2003-06-15)
管管
Brother trees: A family of optimal 1(p)-hamiltonian and 1-edge hamiltonian graphs
(2003-06-15)
Kao, SS
;
Hsu, LH
;
資訊工程學系
;
Department of Computer Science
In this paper we propose a family of cubic bipartite planar graphs, brother trees, denoted by BT(n) with n greater than or equal to 2. Any BT(n) is hamiltonian. It remains hamiltonian if any edge is deleted. Moreover, it remains hamiltonian when a pair of nodes (one from each partite set) is deleted. These properties are optimal. Furthermore, the number of nodes in BT(n) is 6. 2(n) - 4 and the diameter is 2n + 1. (C) 2003 Elsevier Science B.V. All rights reserved.