Browsing by Issue Date, starting with "1998-08-23"

Now showing 1 - 20 of 81925

The photolysis and thermolysis of nitrogen-containing sultines in the preparation of heterocyclic-O-quinodimethanes.
(1998-08-23)
Chung, WS
;
Liu, JH
;
應用化學系
;
Department of Applied Chemistry
Synthetic studies towards laurobtusol.
(1998-08-23)
Ho, TL
;
Yeh, ST
;
應用化學系
;
Department of Applied Chemistry
青藤書屋那根青藤
(1998-08-26)
管管
秋瑾先生的擘窠大書
(1998-08-27)
管管
林耀堂繪筆閱讀詩人
(1998-08-27)
黃寶萍
On metric dependence of Vilkovisky-DeWitt effective potential
(1998-08-30)
Kao, WF
;
Lin, SW
;
電子物理學系
;
物理研究所
;
Department of Electrophysics
It is known that the Vilkovisky-DeWitt effective potential for Einstein gravity depends on the choice of the metric of configuration space. We will show that this metric dependence occurs not only in gauge field theories, but also in scalar fields as well as other field theories with "unnatural" initial choices of metric. This means that the problem of metric dependence relates to initial field parametrization but not gauge symmetry.
三昧書屋的小魯迅
(1998-08-31)
管管
On the stability of the hybrid-damped resolved-acceleration control
(1998-09-01)
Lin, SK
;
Wu, SL
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper points out that the stability analysis of the hybrid-damped resolved-acceleration control in our earlier work is incomplete, since the stability was concluded directly from the fact that the joint velocities come to rest as time approaches infinity. A similar incomplete technique was also used in the work of Wampler and Leifer to prove the stability of a damped least-squares resolved-acceleration control scheme. In this paper, we use LaSalle's invariance principle rigorously to show that the solution trajectory of the hybrid-damped resolved-acceleration control will eventually come to the target without steady-state error or will stay at a kinematic singular point with some steady-state error. Discussions on the case of staying at a singular point are also given. (C) 1998 John Wiley & Sons, Inc.
Dilation to the unilateral shifts
(1998-09-01)
Takahashi, K
;
Wu, PY
;
應用數學系
;
Department of Applied Mathematics
The classical result of Foias says that an operator power dilates to a unilateral shift if and only if it is a C-.o contraction. In this paper, we consider the corresponding question of dilating to a unilateral shift. We show tht for contractions with, at least one defect index finite, dilation and power dilation to some unilateral shift amount to the same thing. The only difference is on the minimum multiplicity of the unilateral shift to which the contraction can be (power) dilated. We also obtain a characterization of contractions which are finite-rank perturbations of a unilateral shift, generalizing the rank-one perturbation result of Nakamura.
羅漢床上數羅漢
(1998-09-01)
管管
Diatomic molecule under pulsed field: One-dimensional versus full-dimensional studies
(1998-09-01)
Lin, JT
;
Chuu, DS
;
Jiang, TF
;
電子物理學系
;
物理研究所
This work investigates the dissociation dynamics of a diatomic molecule under the chirped pulse with the vibrational and rotational degrees of freedom. Results obtained herein are also compared with those of the conventionally used one-dimensional (ID) model. According to the comparison, the 1D model still provides valuable information such as dissociation dynamics. Meanwhile, predictions such as harmonic generation spectrum from the 1D model are impractical.
On stationarizability for nonstationary 2-D random fields using discrete wavelet transforms
(1998-09-01)
Wu, BF
;
Su, YL
;
電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
The emphasis in this correspondence is on the study of nonstationary two-dimensional (2-D) random fields with wide-sense stationary increments, wide-sense stationary jumps, and 2-D fractional Brownian motion (fBm) fields. The effort made in this work is to develop a realizable method of stationarization provided for nonstationary 2-D random fields. We also present the correlation functions of the discrete wavelet transform relating to 2-D fBm fields that will decay hyperbolically fast.
ZK-type dual-lead worm and worm gear drives: Contact teeth, contact ratios and kinematic errors
(1998-09-01)
Bair, BW
;
Tsay, CB
;
機械工程學系
;
Department of Mechanical Engineering
Contact ratio is an important gear design parameter for gear bending and contact stresses. A higher contact ratio may reduce the stresses and kinematic errors of the gear set. In this study, we calculate the kinematic error of the ZK-type dual-lead worm gear set by applying the tooth contact analysis (TCA) method. Two kinds of contact ratios, the instantaneous contact teeth (ICT) and the average contact ratio (ACR), are investigated and calculated by applying TCA method. ICT is an important design parameter for a dual-lead worm gear set when the gear set is used in a machine subjected to large impact forces. ACR is also a useful design factor for assessing gear tooth strength and dynamic load. If gear surface elastic deformation 3 mu m is allowed for the worm gear set, the ICT may have 2, 3 or 4 teeth and the ACR reveals that the ZK-type dual-lead worm gear drive is a high-contact-ratio gear set. It is found that this type of worm gear set with a shorter center distance assembly can increase the value of ACR during the gear meshing. Illustrative examples presented herein demonstrate the effects of gear parameters on contact teeth, contact ratios, average contact ratios and kinematic errors under various conditions.
Improved output ESD protection by dynamic gate floating design
(1998-09-01)
Chang, HH
;
Ker, MD
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A dynamic gate Boating design is proposed to improve ESD robustness of the CMOS output buffers with small drive capability. By using this novel design, the human-body-model (machine-model) ESD failure threshold of a 2-mA CMOS output buffer has been practically improved from 1 KV (100 V) to greater than 8 KV (1500 V) in a 0.35-mu m CMOS process.
A new algorithm for lossless still image compression
(1998-09-01)
Chuang, TJ
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
This paper presents a spatial domain method for lossless still image compression using a new scheme: base switching (BS). The given image is partitioned into non-overlapping fixed-size subimages. Different subimages then get different compression ratios according to the base values of the subimages. In order to increase the compression ratio, a hierarchical technique is also used. It is found that the compression ratio of the proposed algorithm can compete with that of the VBSS and the international standard algorithms known as JBIG and Lossless JPEG. In addition, when the BS method is compared with the S + P method, which is an excellent frequency domain method that used EZW, although S + P method gains about 9% increase in the compression ratio, its encoding time (excluding I/O) is about three times longer than ours. The math theory needed to build up the proposed compression scheme is also provided. (C) 1998 Published by Elsevier Science Ltd on behalf of the Pattern Recognition Society. All rights reserved.
A logical fault model for library coherence checking
(1998-09-01)
Tung, SW
;
Jou, JY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A library is the basis of modularized design now. Most operations of CAD tools are based on cell definitions in a library. In this paper, we first give a definition of a library and describe the complexity of library verification. A unified automatic test pattern generation and verification environment is then proposed. The amount of library data coherence checking is reduced to functional simulation on different views of the cells. In order to reduce the number of lest vectors and the amount of simulation time, a Port Order Fault (POF) model is proposed. Using the POF model and the sensitized path approach [1] to generate test vectors, the proposed approach could effectively reduce the complexity of the functional test vectors from O(2(n)) to O(n) for cells with n inputs. Using the POF model, the test sequence can also detect timing inconsistency under the verification environment.
Influence of thermal boundary resistance on bolometric response of high-T-c superconducting films
(1998-09-01)
Wu, JP
;
Shih, CU
;
Chu, HS
;
機械工程學系
;
Department of Mechanical Engineering
This work presents a thermal analysis on predicting the temperature increase and the voltage response of high-T-c superconducting bolometers. To consider the thermal boundary resistance between film and substrate, an acoustic mismatch model (AMM), a diffusive mismatch model (DMM), and an interfacial layer model (ILM) are employed. The thermal boundary resistance significantly influences the voltage response. Additionally, several common substrates are examined. SrTiO3 (100) or LaAlO3 (100) is a better substrate for high-T-c superconducting bolometers. Furthermore, we demonstrated that there are several factors to affect the voltage response, such as the pulse duration for a constant total incident energy or a fixed highest incident heat flux, the pulse distribution function in time, optical penetration depth, the thermal conductivities of the film and substrate, initial operating temperature, thickness ratio, and the amount of incident heat flux. One interesting finding was that when compared with experimental data, all the theoretical values from the present study as well as the other previously theoretical treatment overestimate the voltage response near the transition temperature. (C) 1998 Elsevier Science Ltd. All rights reserved.
The path-partition problem in bipartite distance-hereditary graphs
(1998-09-01)
Yeh, HG
;
Chang, GJ
;
應用數學系
;
Department of Applied Mathematics
A path partition of a graph is a collection of vertex-disjoint paths that cover all vertices of the graph. The path-partition problem is to find a path partition of minimum size. This paper gives a linear-time algorithm for the path-partition problem in bipartite distance-hereditary graphs.
A Petri net approach to early failure detection and isolation for preventive maintenance
(1998-09-01)
Yang, SK
;
Liu, TS
;
機械工程學系
;
Department of Mechanical Engineering
To improve preventive maintenance, this study uses a hybrid Petri net modelling method coupled with parameter trend and fault tree analysis to perform early failure detection and isolation. A Petri net arrangement is proposed that facilitates alarm, early failure detection, fault isolation, event count, system state description and automatic shutdown or regulation. These functions are very useful for health monitoring and preventive maintenance of a system. A fault diagnosis system for district heating and cooling facilities is employed as an example to demonstrate the proposed method. (C) 1998 John Wiley Br Sons, Ltd.
A study of tilt angle effect on Halo PMOS performance
(1998-09-01)
Su, JG
;
Wong, SC
;
Huang, CT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The Halo structure is usually adopted in deep submicrometer MOS devices for punchthrough prevention. The tilt angle of the Halo implant determines the dopant distribution which induces anti-punchthrough operation. In this paper, we investigate the impact of the tilt angle on the Halo PMOS device performance via two-dimensional (2D) simulations. We find that the ratio of on-current to off-current is constant for all tilt angles of Halo implant, implying an equivalent DC performance for all tilt angles. The equivalence can be traced back to a self compensation between the body factor and source resistance. The result :implies that a low tilt angle should be adopted for Halo devices, for it gives a small threshold voltage and thus a high noise margin. The methodology used in analyzing body factor and source resistance can also be applied to analyze other devices. (C) 1998 Elsevier Science Ltd. All rights reserved.