Browsing by Author "Liu, SJ"

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A beam-forming technique for leaky-wave antennas
(2001-01-20)
Chen, IY
;
Wang, CJ
;
Liu, SJ
;
Jou, CF
;
傳播研究所
A beam-forming technique for leaky-wave antennas (LWAs) which can switch electronically in three different radiation patterns is developed in this letter. A simple two-terminal feeding microstrip-line LWA works as a radiating element. By varying the phase of the two injection signals from 0 to 180 degrees, the emitting power from the LWA can produce three different radiation modes: the normal mode (one sharp beam), the difference mode (Delta), and the sum mode (Sigma). The antenna displays large-bandwidth characteristics, and can be useful near crossroads for collision avoidance or in the radio location of vehicles. (C) 2001 John Wiley & Sons, Inc.
A comparison between the Fehrenbacher-Rice and the Liechtenstein-Mazin models
(2000-11-01)
Liu, SJ
;
Lin, JY
;
Chen, JM
;
Nachimuthu, P
;
Luo, CW
Unoccupied electronic states of Y1-xPrxCu3O7-y (x = 0 - 1) thin films have been investigated using high-resolution polarization-dependent O K-edge x-ray absorption spectroscopy (XANES). After determining the hole distribution among different oxygen sites of the Pr-doped thin films, we compare the experimental data with the Fehrenbacher and Rice (FR) model and the Liechtenstein and Mazin (LM) model, both of which are based on the hybridization of Pr 4f(z(x2-y2)) and O 2p(pi) orbitals in PrBa2Cu3O7-y. Our experimental results are more consistent with the FR model.
A fault tolerant shared memory ATM switch
(1997)
Lee, TH
;
Liu, SJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we present a fault tolerant ATM switch based on the shared memory architecture [6]. We study first the effect of a single fault to an ATM switch. Basically, a single fault in an ATM switch results in cell mis-delivery, out-of-sequence, corruption, and/or loss. We propose to add output port address, sequence number, and CRC checking to each cell for on-line fault detection. Some single faults which cause cell loss cannot be detected without wing multiple switch copies. Therefore, we propose to we a duplex system for detecting these faults and also for fault tolerant. We then design a fault tolerant switch based on the shared memory architecture [6]. Our proposed implementation can tolerate a single fault without losing cells in most cases.
Anisotropic electronic structure of in-plane aligned a-axis YBa2Cu3O7-delta thin films
(2003-09-01)
Luo, CW
;
Chen, MH
;
Liu, SJ
;
Wu, KH
;
Juang, JY
Polarization-dependent x-ray absorption near-edge spectra (XANES) of the O 1s has been measured on a highly in-plane aligned a-axis YBa2Cu3O7-delta (YBCO) thin film. The in-plane XANES, with the electric field E of the linearly polarized synchrotron light being parallel to the b or c axis of YBCO films (E//b or E//c) were obtained in a normal-incidence alignment. The XANES for E//a was then calculated from the data obtained by varying the angle. The results lend strong support to those obtained by using detwinned YBCO single crystals in all crystalline orientations, including the extrapolated c-axis spectra. (C) 2003 American Institute of Physics.
Anisotropic O 2p-Mn 3d unoccupied states in La1-xMnO3: an X-ray absorption spectroscopy study
(2002-02-01)
Lin, JY
;
Chen, CW
;
Liu, YC
;
Liu, SJ
;
Wu, KH
We have studied La1-xMnO3 thin films, which show the metal-insulator transition similar to La1-xCaxMnO3. The transport and magnetic properties are measured, X-ray absorption spectroscopy is employed to investigate the electronic structure. Surprisingly, the electronic structure of La1-xMnO3 shows large anisotropy. Our results suggest that La1-xMnO3 is unique among manganites. (C) 2002 Elsevier Science B.V. All rights reserved.
Electronic and magnetic instability in Pr0.65Ca0.25Sr0.1MnO3
(2003-09-01)
Mollah, S
;
Huang, HL
;
Liu, SJ
;
Ho, PL
;
Huang, WL
Electronic and magnetic instability in polycrystalline Pr0.65Ca0.25Sr0.1MnO3 manganite has been established from a systematic study of resistivity (p), magnetization (M) and specific heat (C). The sample shows a charge ordering transition at T-CO similar to 200 K, an antiferromagnetic (AFM) ordering transition at T-N similar to 175 K, a metal-insulator (MI) transition at T-MI similar to 80 K and an unusual magnetic ordering transition at T-M(*) similar to 45 K in the absence of magnetic fields. Though the C data do not show any anomaly at T-MI for MI transition, these illustrate a much smaller anomaly than expected one at T-M* and is suppressed by magnetic fields. This indicates that the unusual magnetic ordering in this sample is of canted, fluctuated or phase separation of AFM and ferromagnetic in nature which is established from the T-H phase diagram, as well as the thermal and magnetic hysteresis in p, M and C. (C) 2003 Elsevier Science B.V. All rights reserved.
Grain-boundary magnetoresistance of CrO2 films grown on TiO2-buffered LaAlO3 substrates
(2003-08-01)
Liu, SJ
;
Juang, JY
;
Wu, KH
;
Uen, TM
;
Gou, YS
The magnetic and magnetotransport properties of predominantly (110)-oriented CrO2 films grown on TiO2-buffered LaAlO3 substrates were investigated. The atomic force microscopic images revealed that the as-grown CrO2 films are granular. The magnetic measurements indicated that in-plane coercive fields are about 60 Oe and 100 Oe at 300 K and 7 K, respectively. The as-grown films are semiconductive below 75 K; a magnetoresistance with a DeltaR/R-0 ratio of -13% in a magnetic field of 5 T was observed at 5 K, which is absent in high-quality epitaxial films. The coincidence between the coercive field and the peaks of the magnetoresistive loop measured at low temperatures indicates that spin-dependent scattering plays a crucial role in the transport properties.
Growth and transport properties of (110)-oriented La2/3Sr1/3MnO3 thin films on TiO2-Buffered Si (100) substrates
(2003-03-15)
Liu, SJ
;
Chen, SF
;
Juang, JY
;
Lin, JY
;
Wu, KH
The growth and transport properties of (110)-oriented La2/3Sr1/3MnO3 thin films on TiO2-buffered silicon substrates by pulsed-laser deposition are reported. An insulator-metal transition associated with a ferromagnetic transition was observed at about 360 K. Magnetic measurements showed that in-plane coercive fields are about 60 Oe and 300 Oe at 300 K and 5 K, respectively. A magnetoresistance with a Deltarho/rho(H = 0) ratio of -20% in a magnetic field of 5 T was observed not only near the insulator-metal transition temperature but also below 30 K. Moreover, a T-2- to T-3-dependence crossover of resistivity was observed around 60 K, indicating that an unconventional one-magnon scattering may have occurred.
Hole distribution in YxPr1-xBa2Cu4O8 and YxPr1-xBa2Cu3O7 probed by X-ray absorption spectroscopy
(2004-08-01)
Chen, JM
;
Liu, SJ
;
Lee, JM
;
Lin, JY
;
Gou, YS
Utilizing high-resolution O K-edge X-ray absorption spectra, we report a comparative study on the variation of hole states with Pr doping for Y-x Pr1-xBa2Cu3O7 and YxPr1-xBa2 Cu-4 O-8. The depletion rate of hole carriers in the CuO2 planes with Pr doping in YxPr1-xBa2Cu4 O-8 is considerably slower than that in YxPr1-xBa2Cu3O7. The oxygen content affects the depletion rate of hole carriers in cuprates with Pr doping. (C) 2004 Elsevier B.V. All rights reserved.
Industrial development and structural adaptation in Taiwan: Some issues of learned entrepreneurship
(1998-11-01)
Liu, SJ
;
科技管理研究所
;
Institute of Management of Technology
The industrialization of Taiwan has been a remarkable phenomenon. This paper discusses recent changes in Taiwan's manufacturing industries and the response of both government and private enterprises to the challenges presented by a dynamic environment and by global competition. Several cases are discussed in light of the activities and adjustments on the part of government and of the public sector, of small and medium business, and of high-tech industries. Government participation over the last four decades has been and will remain pivotal in economic growth and in achieving adjusted positioning. Taiwan's personal computer and IC industries have evolved from an infant stage through an accelerated growth period and are now extending to other technologically associated industries. The small enterprise sector is in a transitional stage of upgrading competitive niches. The unsuccessful stories of biopharmaceuticals and automobiles are discussed in terms of what they reveal about government intervention and the performance of public research institutes. Active patenting activities by Taiwan enterprises and public research institutes illustrate the accumulated technological capability found on this island. The accelerated sociopolitical movements toward democracy, the bureaucratic management of public issues, and the political and economic interactions between Taiwan and China, exert significant effects on the industrial structure and on government's role in directing the industrial evolution. This article presents an integrated reasoning of Taiwan's economic success, It reveals that the neoclassical doctrine of market efficiency is fundamentally valid, and that the effective commercialization of national technological capability has created Taiwan's industrial evolution. Market governance proved to be an efficient short-term policy instrument when the latecomer strategy of cost leadership was applied. A conceptual model of industrial competition and technology commercialization is also proposed to facilitate the methodological analysis. This study concludes that learning capability and human capital will determine the endurance of Taiwan's industrial success, and that entrepreneurship must be learned by the state, as well as by the private firms.
Industrial development and structural adaptation in Taiwan: Some issues of learned entrepreneurship
(1998-11-01)
Liu, SJ
;
科技管理研究所
;
Institute of Management of Technology
The industrialization of Taiwan has been a remarkable phenomenon. This paper discusses recent changes in Taiwan's manufacturing industries and the response of both government and private enterprises to the challenges presented by a dynamic environment and by global competition. Several cases are discussed in light of the activities and adjustments on the part of government and of the public sector, of small and medium business, and of high-tech industries. Government participation over the last four decades has been and will remain pivotal in economic growth and in achieving adjusted positioning. Taiwan's personal computer and IC industries have evolved from an infant stage through an accelerated growth period and are now extending to other technologically associated industries. The small enterprise sector is in a transitional stage of upgrading competitive niches. The unsuccessful stories of biopharmaceuticals and automobiles are discussed in terms of what they reveal about government intervention and the performance of public research institutes. Active patenting activities by Taiwan enterprises and public research institutes illustrate the accumulated technological capability found on this island. The accelerated sociopolitical movements toward democracy, the bureaucratic management of public issues, and the political and economic interactions between Taiwan and China, exert significant effects on the industrial structure and on government's role in directing the industrial evolution. This article presents an integrated reasoning of Taiwan's economic success, It reveals that the neoclassical doctrine of market efficiency is fundamentally valid, and that the effective commercialization of national technological capability has created Taiwan's industrial evolution. Market governance proved to be an efficient short-term policy instrument when the latecomer strategy of cost leadership was applied. A conceptual model of industrial competition and technology commercialization is also proposed to facilitate the methodological analysis. This study concludes that learning capability and human capital will determine the endurance of Taiwan's industrial success, and that entrepreneurship must be learned by the state, as well as by the private firms.
International development of Taiwan's information industry: An empirical study on human resource strategy of overseas subsidiaries
(1998-08-01)
Liu, SJ
;
Huang, TL
;
Chen, QH
;
科技管理研究所
;
Institute of Management of Technology
Since the 1980's, personal computers (PC's) and semiconductors have emerged as Taiwan's two leading high-technology industries. As of the 1990's, Taiwan has attained third place among PC manufacturers, and PC's and peripherals have become Taiwan's largest export products. Entrepreneurial small businesses, fierce competition in the local economy, and efficient industrial networking characterize Taiwan's PC industry, with flexible production and shortened time to market. This study investigates the human resource strategies of overseas subsidiaries of Taiwan's information enterprises, primarily the PC production industry. Gaining the comparative advantages of production from foreign resources of labor, materials, and key components are among the prime concerns. Direct access to foreign markets and marketing information constitute that more offices be established abroad. In general, internationalization of Taiwan's PC industry partakes more of a headquarters-controlled style of global management, Overseas subsidiaries are essentially extensions of Taiwan- and manufacturing-based PC enterprises. This study integrates theoretical frameworks of the eclectic paradigm and the integration-responsiveness models and explores four strategic patterns of human resource on the basis of two dimensions: consistency with parent-company policy and local responsiveness of a foreign subsidiary, Statistical measures as well as qualitative analysis reveal that both domestic corporate characteristics and overseas local features significantly influence management policy, While Taiwanese information enterprises are increasingly moving toward global expansion, the majority are at a learning stage in international business development. Internalization of Taiwan's PC industry primarily depends on the manufacturing capability of local headquarters and joint ventures with foreign companies. The manufacturing-based PC industry in Taiwan is moving toward key component production and brand marketing while integrating global resources to compete against established transnational corporations.
Liquid crystal display industry in Taiwan
(1997)
Liu, SJ
;
Lee, JF
;
交大名義發表
;
科技管理研究所
;
National Chiao Tung University
This paper presents an overview of Taiwan's LCD (Liquid crystal display) industry to illustrate the emergence of competitive advantages of Taiwan's high-tech development. It shows that Taiwanese firms are evolving from manufacturing labour-intensive items of LCDs to more technology intensive TFT LCD. The worldwide LCD demands are growing at a fast pace and Japan leads both in technology and economy of scale. South Korea is next to Japan in terms of market share and production scale, while the USA and European countries are trying to keep up with the world demands. A patent analysis was performed to analyze the technology trend and leading companies. Japan dominates the technology leadership and SHARP plays a key role of TFT technology development. The increase in Labour wages cause Taiwan's industry to be less competitive in the labour-intensive products of TN-LCDs. However, supportive industrial policy, experienced engineers, well-developed IC infrastructures, ample sources of capital investment, and quick response to market needs, serve as the vehicle ibr Taiwan's competitiveness in the international arena of LCD industry.
Magnetoresistance of La0.7Ca0.3MnO3 thin film biepitaxial step junctions
(2003-08-01)
Chen, SF
;
Chang, WJ
;
Liu, SJ
;
Juang, JY
;
Lin, JY
The biepitaxial La0.7Ca0.3MnO3 (LCMO) thin films grown on SrTiO3 substrates using a buffer layer of anatase TiO2 were fabricated. The magnetoresistance (MR) of biepitaxial step junction (BSJ) across the boundary layer of biepitaxial LCMO (0 0 1) and LCMO (I 10) film was investigated. The temperature and field dependence of MR for BSJ are qualitatively similar to those obtained in other type of artificial grain boundaries with a comparable MR ratio at low temperatures. However, the observed linear current-voltage characteristic across BSJ is in sharp contrary to the commonly reported non-ohmic characteristics. The results are consistent with features predicted by the model of spin-dependent transport across a depressed magnetic ordering and metallic-like junction layer. (C) 2003 Elsevier Science B.V. All rights reserved.
Managing environmental safety of liquid radwaste disposal with modeling and monitoring techniques
(1994)
Liu, SJ
;
Liu, TDS
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科技管理研究所
;
Institute of Management of Technology
Peculiar hole doping by Ca substitution in cuprate superconductors
(2003-05-01)
Lin, JY
;
Chung, PC
;
Liu, SJ
;
Hsiang, CC
;
Lin, PH
The doping effect of Ca substitution in Y0.7Ca0.3Ba2Cu3Oy has been studied for y=6.9 and 6 by the x-ray absorption near edge spectroscopy (XANES). While Ca doping leads to an obvious increase in hole concentration in the CuO2 planes in Y0.7Ca0.3Ba2Cu3O6.9, XANES indicates absence of this doping effect in Y0.7Ca6.3Ba2Cu3O6. These two contradict results suggest that the doping effect by Ca substitution could be sensitive to the oxygen content when y similar to6.0. Comparisons with others' works are made.
Polarization-dependent X-ray absorption spectroscopy of in-plane aligned (100) YBa2Cu3O7-delta thin films
(2003-05-01)
Luo, CW
;
Liu, SJ
;
Chen, MH
;
Wu, KH
;
Lin, JY
Polarization-dependent X-ray absorption spectra (XAS) on the 0 Is edge has been measured on a highly in-plane aligned (100) a-axis YBa2Cu3O7-delta (YBCO) thin films. The in-plane XAS, that is, the electric field E of the linearly polarized synchrotron light parallels to b- or c-axes of YBCO films (Eparallel tob or Eparallel toc), were obtained in a normal-incidence alignment. Furthermore, the XAS for Eparallel toa was calculated from the oblique incidence to the sample with different angles. The present results are consistent with those obtained by using detwinned YBCO single crystals. (C) 2003 Elsevier Science B.V. All rights reserved.
Possible evidence for the existence of the Fehrenbacher-Rice band: O K-edge XANES study on Pr1-xCaxBa2Cu3O7
(2002-04-01)
Hong, IP
;
Lin, JY
;
Chen, JM
;
Chatterjee, S
;
Liu, SJ
X-ray absorption near edge structure (XANES), resistivity, and thermoelectric power have been measured on Pr1-xCaxBa2Cu3O7. These data reveal an intriguing electronic structure in Pr-doped cuprates. The absorption peak in XANES associated with the Fehrenbacher-Rice (FR) band has been identified. The Ca-doped holes in Pr1-xCaxBa2Cu3O7 go to both the Zhang-Rice (ZR) and FR bands. Comparative studies on the related samples suggest that the FR band is partially filled and highly localized. Implications of these results on other recent experiments, such as the observation of superconductivity in PrBa2Cu3O7 single crystals, are discussed.
Pr-induced superconductivity suppression in YxPr1-xBa2Cu4O8 probed by soft-X-ray absorption spectroscopy: a comparative studies of YxPr1-xBa2Cu4O8 and YxPr1-xBa2Cu3O7
(2003-03-07)
Chen, JM
;
Liu, SJ
;
Lee, JM
;
Hong, IP
;
Lin, JY
The variation of hole states with Pr doping for YxPr1-x Ba2Cu3O7 and YxPr1-xBa2Cu4O8 has been investigated by O K-edge X-ray absorption spectroscopy. Upon Pr substitution, T-c suppression rate in YxPr1-xBa2Cu4O8 is slower than that in YxPr1-xBa2Cu3O7. For both systems, hole carriers in the CuO2 planes and CuO chains decrease monotonically with increasing Pr doping level. The depletion rate of hole carriers in the CuO2 planes with Pr doping in YxPr1-xBa2Cu4O8 is considerably slower than that in YxPr1-xBa2Cu3O7. The oxygen content affects the depletion rate of hole carriers in cuprates with Pr doping. (C) 2003 Elsevier Science B.V. All rights reserved.
Soft x-ray absorption spectroscopy studies of (110) YBa2Cu3O6.9 thin film
(2003-03-01)
Liu, SJ
;
Juang, JY
;
Wu, KH
;
Uen, TM
;
Gou, YS
Unoccupied states of the (110) YBa(2)Cu(3)O(6.)9 (YBCO) thin films were investigated by the Eparallel toab and Eparallel toc polarized O 1s x-ray absorption near edge structure (XANES) spectroscopy. With correction of the self-absorption effect, the Eparallel toab O 1s XANES spectra of the (110) YBCO films obtained from the normal incidence geometry and grazing incidence geometry are very similar. After the self-absorption correction, the Eparallel toc spectrum of the (110) YBCO film obtained from the normal incidence geometry is almost identical to that of the (001) YBCO film obtained from the grazing incidence geometry. Hole distribution over the different oxygen sites has been derived. The hole number in the apical sites in some thin films obtained in the present. investigation is larger than that from the previous x-ray absorption studies of single crystals and from the theoretical calculations. The comparison of the XANES spectra between the (001) and (110) YBCO thin films is also presented. (C) 2003 American Institute of Physics.