Browsing by Author "Lin, MC"

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A gain-clamped S-band erbium-doped fiber amplifier using fiber Bragg grating
(2006-05-15)
Yeh, CH
;
Lin, MC
;
Chi, S
;
光電工程學系
;
Department of Photonics
We propose and investigate experimentally a gain-clamped S-band erbium-doped fiber amplifier module, employing a fiber Bragg grating to serve as a reflected element to lase a saturated tone injected into the module, by forward optical feedback method. In addition, different injected powers of the saturated tone are used to realize the performances of gain and noise figure for the proposed amplifier over the effectively wavelength range of 1478-1520 nm. (C) 2005 Elsevier B.V. All rights reserved.
A maskable memory architecture for rank-order filtering
(2004-05-01)
Dung, LR
;
Lin, MC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a novel implementation Of rank-order filtering using maskable memory. Based on a generic bit-sliced rank-order filtering algorithm the proposed design uses a special-defined memory, called parallel maskable memory (PMM) to realize major operations of rank order filtering, threshold decomposition and polarization. In conventional designs, these operations are usually implemented as logic circuit and require complex computation. Using the memory-oriented architecture, the proposed rank-order filter can benefit from high flexibility, low cost and high speed. PMM has features of bit-sliced read partial write, and pipelined processing. Bit-sliced read and partial write are driven by maskable registers. The maskable registers allows PMM to configure operating bits,for parallel read/write operations. Combining the bit-sliced read with polarization selector allows PMM to perform polar determination while the partial write achieves polarization. Recursively combining the bit-sliced read and partial write, PMM can effectively realizes rank-order filtering in term -3 of cost and speed(I).
A maskable memory architecture for rank-order filtering
(2004-01-01)
Lin, MC
;
Dung, LR
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a novel implementation of rank-order filtering using maskable memory. Based on a bit-serial rank-order filtering algorithm the proposed design uses a special-defined memory, called parallel maskable memory (PMM) to realize major operations of rank-order filtering, polarization and update. Using the memory-orient architecture, the proposed rank-order filter can. benefit from high flexibility, low cost and high speed. PMM has features of bit-sliced read, partial write, and pipelined datapath. Bit-sliced read and partial write are driven by maskable registers. The maskable registers allows PMM to configure operating bits. The bit-sliced read with a polarization selector allows PMM to perform polar determination while the partial write helps next-bit update. Recursively combining the bit-sliced read and partial write, PMM can effectively realizes rank-order filtering in terms of cost and speed.
Ab initio studies of ClOx radical reactions: V. Evidence for a new path in the Cl+ClOOCl reaction
(2003-05-15)
Zhu, RS
;
Lin, MC
;
交大名義發表
;
National Chiao Tung University
The mechanism for the reaction Cl + ClOOCl has been investigated by ab initio molecular orbital and transition-state theory calculations. The result shows that the reaction can produce both Cl-2 + ClOO and Cl2O + ClO. The former product pair can be formed by direct and indirect abstraction paths. The direct abstraction path, which dominates at low temperatures, takes place barrierlessly with the rate constant k(1) = 1.53 x 10(-13)T(1.1) exp(118/T) cm(3) molecule(-1) s(-1) in the temperature range of 200-1000 K. The rate constant of the indirect path, which occurs via the two isomers of the Cl-O(Cl)OCl complex lying 3 kcal/mol below the reactants, k(1)' = 7.14 x 10(-12)T(0.86) exp(-2370/T) cm(3) molecule(-1) s(-1), accounting for less than 0.1% of the Cl-2 yield at 298 K but increasing to about 46% at 1000 K. The new Cl2O + ClO products can be produced by the fragmentation of the two complexes; the rate constant for their formation was found to be pressure-independent and can be expressed by k(2) = 2.19 x 10(-14)T(0.70) exp(-1110/T) cm(3) molecule(-1) s(-1) covering the temperature range of 200-1000 K. Above room temperature, Cl2O formation becomes competitive; for example, its branching ratios, k(2)/k(t), are predicted to be 0.19, 0.55, and 0.62 at 298, 500, and 1000 K, respectively. The predicted total rate constant agrees closely with available experimental results. The heat of formation of ClOOCl has been examined in detail using different reactions and computational methods. The results of these calculations converge to Delta(f)Hdegrees(0)(ClOOCl) = 30 +/- 2 kcal/mol.
Ab initio studies of ClOx reactions. 3. Kinetics and mechanism for the OH plus OClO reaction
(2003-02-20)
Xu, ZF
;
Zhu, RS
;
Lin, MC
;
交大名義發表
;
National Chiao Tung University
The mechanism for the OH + OClO reaction on the singlet and triplet surfaces and its rate constants for formation of various products have been investigated by means of ab initio molecular orbital theory and variational RRKM theory calculations. The geometric parameters of stationary points were optimized at the B3LYP level of theory with the 6-311G(d,p) and 6-311+G(3df,2p) basis sets, and the potential energy surfaces were evaluated at the G2M(CC2)//B3LYP/6-311+G(3df,2p) level of theory. Three main product channels, all located on the singlet PES, have been identified: (1) HOO + ClO, (2) HOCl + O-1(2), and (3) HOClO2, the association product. The predicted results show that the rate constants for channels 1 and 2 are pressure-independent up to 1000 atm and that for channel 3 is strongly pressure dependent. Below 1000 K, all rate constants were found to vary negatively with temperature. The individual and total rate constants in the temperature range from 200 to 1000 K at 1 Torr He pressure can be represented by k(1)(T) = 1.22 x 10(-22)T(2.75) exp(1682/T), k(2)(T) = 5.47 x 10(-20)T(2.07) exp(2064/T), k(3)(T) = 1.37 x 10(4)T(-6.61) exp(-536/T) (200-500 K) and 4.99 x 10(54)T(-22.36) exp(-9807/T) (500-1000 K), and k(tot)(T) = 1.78 x 10(-20)T(2.25) exp(2100/T) in units of cm(3) molecule(-1) s(-1). The predicted rate constant, with the HOCl + O-1(2) as the major products in the 300-500 K range, agrees well with available experimental data obtained at 1 Torr He pressure. The high- and low- pressure limits of k(3) can be effectively given by k(3)(infinity)(T) = 3.24 x 10(-11) T-0.28 exp(- 18/T) cm(3) molecule(-1) s(-1) in 200-2500 K and k(3)degrees(T) = 1.28 x 10(-13)T(-6.36) exp(-635/T) for 200-800 K, 7.37 x 10(84)T(-36.02) exp(-22134/T) for 800-1000 K, and 2.91 x 10(-13)T(-8.42) exp(11500/T) for 1000-2500 K in units of cm(6) molecule(-2) s(-1) with N-2 as the third body.
Ab initio studies of ClOx reactions. IV. Kinetics and mechanism for the self-reaction of ClO radicals
(2003-03-01)
Zhu, RS
;
Lin, MC
;
交大名義發表
;
National Chiao Tung University
The self-reaction of ClO radicals has been investigated by ab initio molecular orbital and variational transition state theory calculations. Both singlet and triplet potential energy surfaces were predicted by the modified Gaussian-2 method. The reaction was shown to take place mainly over the singlet surface by forming ClOOCl (k(1)) and ClOClO (k(1)'). These association processes were found to be strongly pressure dependent and the predicted total rate constants are in good agreement with the experimental data. The predicted second- and third-order rate constants for formation of ClOOCl and ClOClO can be expressed, respectively, in units of cm(3) molecule(-1) s(-1) and cm(6) molecule(-2) s(-1) by k(1)(infinity)=1.6x10(-9)T(-0.67) exp(-64/T), k(1)('infinity)=6.4x10(-9)T(-0.78) exp(-76/T), and k(1)(0)=8.31x10(-20)T(-4.96) exp(-336/T), k(1)(0),=1.72x10(-14)T(-6.99) exp(-926/T) in the temperature range 180-500 K for N-2 as the third body. The observed T, P-dependent data could be best accounted for with the heat of formation of ClOOCl, Delta(f)H(0)(o)(ClOOCl)=29.4+/-1 kcal/mol. The formation of Cl-2+O-2 (2), Cl+ClOO (3), and Cl+OClO (4) products have been confirmed, with the predicted pressure-independent rate constants: k(2)=1.09x10(-13)T(0.66) exp(-1892/T); k(3)=1.36x10(-13)T(0.77)exp(-2168/T); k(4)=6.26x10(-11)T(0.005) exp(-2896/T), respectively, in units of cm(3) molecule(-1) s(-1), covering the temperature range 200-1500 K. These results are also in reasonable agreement with existing experimental kinetic data. (C) 2003 American Institute of Physics.
An analytical approach for the fast design of high-power waveguide windows
(2003-02-01)
Lin, MC
;
Chung, HM
;
Burke, A
;
電子物理學系
;
Department of Electrophysics
An analytical approach is presented to achieve the fast design of high-power waveguide windows. The analytical calculation is compared with the result of numerical simulation via the finite-element code high frequency structure simulator and the experiments of W-band waveguide windows performed at the Stanford Linear Accelerator Center (SLAC), Stanford University, Stanford, CA. The closed form has been carried out to enhance the accuracy and efficiency, and the exact calculation agrees with the experimental results and the numerical simulation very well. (C) 2002 Elsevier Science B.V. All rights reserved.
Behaviour of steel moment connections with a single flange rib
(2003-09-01)
Chen, CC
;
Lee, JM
;
Lin, MC
;
土木工程學系
;
Department of Civil Engineering
This paper presents a study of flange rib moment connections for use in steel moment-resisting frames. The connections are strengthened by welding a vertical rib to the beam flange and the column flange. The rib is characterized by an extension. Finite element analysis and experiments were conducted to elucidate the behaviour of lengthened rib reinforced connections. The results of the finite element analysis established the effectiveness of the lengthened rib in mitigating local stress concentrations and forming the plastic hinge zone in the beam. Two full-scale proof-test specimens behaved as observed by the analysis, and exhibited greater than 3% radians of plastic rotation under cyclic load. Without brittle fracture, both specimens developed a plastic hinge in the beam. Extensive yielding and local buckling occurred in the beam flanges and the web. The connections strengthened with a single flange rib were successfully verified by the test. (C) 2003 Elsevier Ltd. All rights reserved.
Compact 5.2-GHz GaInP/GaAs HBT gilbert upconverter using lumped rat-race hybrid and current combiner
(2005-10-01)
Meng, CC
;
Wu, TH
;
Lin, MC
;
電信工程研究所
;
Institute of Communications Engineering
A compact 5.2-GHz Gibert upconversion mixer is demonstrated using the 2-mu m GaInP/GaAs heterojunction bipolar transistor (HBT) technology. A miniature lumped-element rat-race hybrid and an LC current combiner are used in the LO port and the RF port of the upconversion Gilbert mixer, respectively. The effect of the LC current combiner with inductor loss is established in this letter. An active IF balun is incorporated in. the Gilbert upconverter with no extra power consumption. The fully integrated Gilbert upconverter has conversion gain of 1 dB, OP (1 dB) of -10 dBm, and OIP3 of 2 dBm when input IF = 300 MHz, LO = 4.9 GHz, and output RF = 5.2 GHz.
Cyclic behaviour of unreinforced and rib-reinforced moment connections
(2005-01-01)
Chen, CC
;
Chen, SW
;
Chung, MD
;
Lin, MC
;
土木工程學系
This study investigates the cyclic behaviour of the beam-to-column welded moment connections used in steel moment-resisting frames. Two unreinforced welded connections were tested initially to elucidate the behaviour and failure mode. Test results showed that both specimens failed by the brittle fracture of the beam flange, initiated from the root of the weld access hole. Nonlinear finite element analysis was used to identify the causes of the failure. The stress concentration in the weld access hole region has the potential to cause the beam flange to fracture. Analytical results also demonstrated that reinforcing the connection with a single rib can reduce the concentration of stresses at the root of the weld access hole. Further tests of two specimens whose beam flanges were each reinforced by a single rib revealed that the single rib effectively prevents beam flange fracture in the weld access hole region. (C) 2004 Elsevier Ltd. All rights reserved.
Experimental and theoretical investigations of rate coefficients of the reaction S(P-3)+O-2 in the temperature range 298-878 K
(2004-11-01)
Lu, CW
;
Wu, YJ
;
Lee, YP
;
Zhu, RS
;
Lin, MC
Rate coefficients of the reaction S+O-2 with Ar under 50 Torr in the temperature range 298-878 K were determined with the laser photolysis technique. S atoms were generated by photolysis of OCS with a KrF excimer laser at 248 nm; their concentration was monitored via resonance fluorescence excited by atomic emission of S produced from microwave-discharged SO2. Our measurements show that k(298 K)=(1.92+/-0.29)x10(-12) cm(3) molecule(-1) s(-1), in satisfactory agreement with previous reports. New data determined for 505-878 K show non-Arrhenius behavior; combining our results with data reported at high temperatures, we derive an expression k(T)=(9.02+/-0.27)x10(-19)T(2.11+/-0.15) exp[(730+/-120)/T] cm(3) molecule(-1) s(-1) for 298less than or equal toTless than or equal to3460 K. Theoretical calculations at the G2M (RCC2) level, using geometries optimized with the B3LYP/6-311+G(3df) method, yield energies of transition states and products relative to those of the reactants. Rate coefficients predicted with multichannel RRKM calculations agree satisfactorily with experimental observations; the reaction channel via SOO((1)A') dominates at T<500 K, whereas channels involving formation of SOO((3)A") followed by isomerization to SO2 before dissociation, and formation of SOO((1)A") followed by direct dissociation, become important at high temperatures, accounting for the observed rapid increase in rate coefficient. (C) 2004 American Institute of Physics.
Experimental and theoretical studies of rate coefficients for the reaction O(P-3)+CH3OH at high temperatures
(2005-06-22)
Lu, CW
;
Chou, SL
;
Lee, YP
;
Xu, SC
;
Xu, ZF
Rate coefficients of the reaction O(P-3)+CH3OH in the temperature range of 835-1777 K were determined using a diaphragmless shock tube. O atoms were generated by photolysis of SO2 with a KrF excimer laser at 248 nm or an ArF excimer laser at 193 nm; their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O-2 and He. The rate coefficients determined for the temperature range can be represented by the Arrhenius equation, k(T)=(2.29 +/- 0.18)x10(-10) exp[-(4210 +/- 100)/T] cm(3) molecule(-1) s(-1); unless otherwise noted, all the listed errors represent one standard deviation in fitting. Combination of these and previous data at lower temperature shows a non-Arrhenius behavior described as the three-parameter equation, k(T)=(2.74 +/- 0.07)x10(-18)T(2.25 +/- 0.13) exp[-(1500 +/- 90)/T] cm(3)molecule(-1) s(-1). Theoretical calculations at the Becke-3-Lee-Yang-Parr (B3LYP)/6-311+G(3df,2p) level locate three transition states. Based on the energies computed with coupled clusters singles, doubles (triples) [CCSD(T)]/6-311+G(3df,2p)//B3LYP/6-311+G(3df,2p), the rate coefficients predicted with canonical variational transition state theory with small curvature tunneling corrections agree satisfactorily with the experimental observations. The branching ratios of two accessible reaction channels forming OH+CH2OH (1a) and OH+CH3O (1b) are predicted to vary strongly with temperature. At 300 K, reaction (1a) dominates, whereas reaction (1b) becomes more important than reaction (1a) above 1700 K. (c) 2005 American Institute of Physics.
Experimental and theoretical studies of the rate coefficients of the reaction O(P-3)+HCl at high temperatures
(2002-10-31)
Hsiao, CC
;
Lee, YP
;
Wang, NS
;
Wang, JH
;
Lin, MC
Rate coefficients of the reaction O(P-3) + HCl in the temperature range 1093-3197 K were determined using a diaphragmless shock tube. O atoms in the ground electronic P-3 states were generated either by photolysis Of SO2 with a KrF excimer laser at 248 nm or by pyrolysis of N2O with the shock wave. Their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O-2 and He. Rate coefficients determined in this work show non-Arrhenius behavior, with values consistent with previously reported. measurements for T < 1486 K; they fit well with the equation k(1)(T) = (9.27 +/- 0.03) X 10(-24) T3.67+/-0.18 exp[-(1030 +/- 160)/T] cm(3) molecule(-1) s(-1); listed errors represent one standard deviation in fitting. Theoretical calculations at the CCSD(T)/6-311 +G(d, p) level locate a bent (3)A" (TS1) and a linear (3)A' (TS3) transition state characterized previously. On the basis of the results computed by CCSD(T)/ 6-311 +G(3df,2p)//CCSD(T)/6-311 +G(d,p), the rate coefficients predicted with conventional transition-state theory, including Eckart-tunneling corrections and with variational transition-state theory including zero- and small-curvature tunneling corrections, all agree satisfactorily with experimental observations.
Expression and purification of human placenta lactogen in Escherichia coli
(2006-04-01)
Lan, PC
;
Tseng, CF
;
Lin, MC
;
Chang, CA
;
生物科技學系
There are many growth factors secreted by placenta including growth hormone, placenta lactogen (PL), prolactin, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, and chorionic gonadotropin. For a systematic study of how these growth factors work together to result in the various biological functions and future clinical applications, it is needed to produce enough quantities of each protein. In this paper, we report the cloning of human PL (hPL) and expression by Escherichia coli (E coli). Four kinds of expression vectors containing the hPL gene were transformed into several kinds of suitable host strains and grown at 37 and/or 30 degrees C. Determination of the yield of recombinant hPL by SDS-PAGE reveals that among the various conditions, pQE30-PL in E. coli strain M15[pREP4] expressed the largest amount of recombinant hPL at 37 degrees C. However, the expressed recombinant hPL was accumulated in inclusion body forms. The inclusion bodies were solubilized in 8 M urea and purified by a His(6) tagged affinity column under denaturing condition and the final yield of hPL was determined to be 48 mg/L. Intra-chain disulfide bonds could be formed either by oxidation in the refolding buffer or by air oxidation in the presence of urea. The biological activity was examined by the fact that hPL could stimulate erythroid maturation by the formation of hemoglobin in K-562 cells in the presence of erythropoietin. Initial optimization studies resulted in the production of 282.4 mg/L of hPL. (c) 2005 Elsevier Inc. All rights reserved.
Fiber Bragg grating-based multiplexed sensing system employing fiber laser scheme with semiconductor optical amplifier
(2005-09-01)
Yeh, CH
;
Lin, MC
;
Lee, CC
;
Chi, S
;
光電工程學系
We propose and demonstrate experimentally a multipoint fiber Bragg grating (FBG) sensor system, based on fiber Bragg gratings (FBGs), using a semiconductor optical amplifier (SOA) as a gain medium. Multiple wavelength operation is based on the inhomogeneous broadening effect of the SOA of the sensing system. In addition, the behavior of the proposed sensor. configuration is also studied.
Lifetime analysis of quasibound states in coupled quantum wells
(2003-06-01)
Lin, MC
;
Chuu, DS
;
電子物理學系
;
Department of Electrophysics
A simple time-dependent model is presented to investigate lifetimes of the quasibound states in coupled quantum wells (CQWs). The transfer matrix approach is employed to discretize the conduction-band profile of the heterostructure and form a dispersion equation whose zeros correspond to the complex eigenenergies. Both the bound and quasibound states are extracted numerically in the complex plane by Newton's method. The lower and higher well subbands are found to have negative and positive energy shift, respectively, as following the no level crossing theorem. Besides, the decay rate of the quasibound state is approximately proportional to the absolute energy shift. The quasibound states, which have larger energy shift, have shorter lifetime and decay more quickly. Furthermore, the differences in lifetime between the quasibound states in CQWs can be easily realized as all the wave functions are specially adjusted to form the relative probability density distributions. (C) 2003 Elsevier Science B.V. All rights reserved.
Photodissociation of nitrosobenzene and decomposition of phenyl radical
(2004-09-30)
Tseng, CM
;
Choi, YM
;
Huang, CL
;
Ni, CK
;
Lee, YT
Photodissociation of nitrosobenzene in a molecular beam has been studied by multimass ion imaging techniques. Photodissociation at 248 nm shows that there is only one dissociation channel, i.e., C6H5NO --> C6H5 + NO, regardless of the fact that the other channel, C6H5NO --> C6H4 + HNO, is energetically accessible in agreement with theoretically predicted results. Photodissociation at 193 nm also shows the same dissociation channel. However, about 10% of the C6H5 radicals produced at this wavelength further decomposed into benzyne and H atom, and the dissociation rates of phenyl radical as a function of internal energies were measured. The averaged photofragment translational energies released from the dissociation of nitrosobenzene at 193 and 248 nm are 10.2 and 6.9 kcal/mol, respectively, and fragment distributions are almost isotropic at both wavelengths. In addition, the thermal rate constant for dissociation of C6H5NO has been computed and compared with experimental data; the agreement between theory and experiment is excellent, confirming the most recently reported unusually high A-factor (> 10(17) s(-1)).
Quasistationary states of a relativistic field-emission-limited diode employing a high-transparency mesh anode
(2002-06-03)
Lin, MC
;
Chuu, DS
;
電子物理學系
;
Department of Electrophysics
A relativistic field-emission-limited diode employing a high-transparency mesh anode is investigated via a self-consistent approach. The field emission process is described quantum mechanically by the Fowler-Nordheim equation. The cathode plasma and surface properties are considered within the framework of the effective work function approximation. Space-charge effects are described by Poisson's equation including relativistic effects. Ionization effects at the high-transparency mesh anode are ignored. The numerical calculations are carried out on a time scale much shorter than the emergence of the gap closure. The quasistationary state of the diode exhibits a cutoff voltage. The electric field on the cathode surface is found to be saturated in the high-voltage regime and determined by the effective work function only. (C) 2002 American Institute of Physics.
S-band gain-clamped grating-based erbium-doped fiber amplifier by forward optical feedback technique
(2006-04-03)
Yeh, CH
;
Lin, MC
;
Huang, TT
;
Hsu, KC
;
Ko, CH
An S-band gain-clamped erbium-doped fiber amplifier module, employing a fiber Bragg grating to serve as a reflected element for lasing a saturated tone injected into the module by forward optical feedback method, is proposed and investigated experimentally. Moreover, the performance and behavior of the gain and noise figure in the proposed gain- clamped S-band fiber amplifier have also been discussed in the effectively wavelength range of 1478 to 1520 nm. (c) 2006 Optical Society of America.
Space-charge effects of electrons and ions on the steady states of field-emission-limited diodes
(2005-03-01)
Lin, MC
;
材料科學與工程學系奈米科技碩博班
;
Graduate Program of Nanotechnology , Department of Materials Science and Engineering
Space-charge effects of electrons and ions on the steady state of a field-emission-limited diode (FELD) are investigated via a self-consistent approach. The field-emission process is described quantum mechanically by the Fowler-Nordheim equation. The cathode plasma and surface properties are considered within the framework of the effective work function approximation. Ionization effects at the anode as well as electron space-charge effects are described by Poisson's equation. The numerical calculations are carried out self-consistently to yield the steady states of the bipolar field-emission-limited flow of the FELD. We found that the stationary state of the diode exhibits a cut-off voltage. The electric field on the cathode surface is found to be saturated in the high voltage regime and is determined by the effective work function approximately. In addition, the ion current included in the Poisson's equation has been treated as a tuning parameter. The analytical formula of the electron current density has been derived. The field-emission currents in the presence of saturated ion currents can be enhanced to be nearly 1.8 times of the case with no ion current (c) 2005 American Vacuum Society.