Browsing by Author "Chen, SY"

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A cost model for justifying the acceptance of rush orders
(1996-07-01)
Wu, MC
;
Chen, SY
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
Rush orders are immediate customer demands which exceed the expectation of the currently effective MPS (master production schedule). Even though such orders are quite common to companies in a dynamic market, most existing studies published in the relevant literature seldom discuss the economical justification of accepting such an order. This paper proposes a mixed integer programming model for computing the cost of accepting the production of a rush order. The computed cost value could serve as a valuable reference for justifying the economics of accepting a rush order, and help determine its pricing strategy.
A multiple criteria decision-making model for justifying the acceptance of rush orders
(1997-12-01)
Wu, MC
;
Chen, SY
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Rush orders are immediate customer demands that exceed the expectation of a currently effective MPS (master production schedule). Decision-makers are often hesitant in the decision of accepting such orders. This paper presents a multiple criteria decision-making model for justifying the acceptance of rush orders for an assembly-to-order production system. Four criteria or production objectives are simultaneously considered and a multiple objective programming technique, the e-constraints approach, is adopted to solve the decision-making problem. This model could give the cost estimation for producing a rush order under various combinations of production objectives. The computed cost value could serve as a Valuable reference for justifying the economics of accepting the rush order, and help to determine its pricing strategy.
A multiple criteria decision-making model for justifying the acceptance of rush orders
(1997-12-01)
Wu, MC
;
Chen, SY
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
Rush orders are immediate customer demands that exceed the expectation of a currently effective MPS (master production schedule). Decision-makers are often hesitant in the decision of accepting such orders. This paper presents a multiple criteria decision-making model for justifying the acceptance of rush orders for an assembly-to-order production system. Four criteria or production objectives are simultaneously considered and a multiple objective programming technique, the e-constraints approach, is adopted to solve the decision-making problem. This model could give the cost estimation for producing a rush order under various combinations of production objectives. The computed cost value could serve as a Valuable reference for justifying the economics of accepting the rush order, and help to determine its pricing strategy.
A self-propagating high-temperature synthesis method for Ni-ferrite powder synthesis
(2004-03-25)
Peng, CH
;
Hwang, CC
;
Hong, CK
;
Chen, SY
;
材料科學與工程學系
Ni-ferrite (NiFe2O4) powder was synthesized by a self-propagating high-temperature synthesis (SHS) process using Fe, Fe2O3 and various Ni-containing species (Ni-CSs) as reactants. The reactants were thoroughly mixed and pressed into a cylindrical compact. The compact was ignited by electrical heating under oxygen partial pressures varying between 0.02 and 1.5 MPa. The effects of the type of Ni-containing species, the reactant composition, the oxygen pressure on the combustion temperature, and the product conversion were investigated. X-ray diffraction (XRD) analysis showed that oxygen pressure promoted product conversion. Among several Ni-containing species tested, Ni2O3 was found to give the highest conversion. The product conversion increased with increasing iron content and then decreased with further increase in iron content. Scanning electron microscope (SEM) observations showed that the product synthesized is mostly in the form of agglomerated fine particles with submicron size (0.1-0.5 mum). Hysteresis behavior analysis showed that the product as synthesized possessed better soft magnetic properties when compared with commercial Ni-ferrite prepared by the solid reaction method. (C) 2004 Elsevier B.V. All rights reserved.
Aging behavior and recovery of polarization in Sr0.8Bi2.4Ta2O9 thin films
(2000-03-15)
Chen, SY
;
Lee, VC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Ferroelectric thin films of bismuth-containing layered perovskite Sr0.8Bi2.4Ta2O9 (SBT) have been prepared by both metalorganic decomposition (designated as MOD-SBT film) and magnetron sputtering (designated as sputtering-SBT film) processes. SBT thin films are well known to exhibit free-fatigue behavior with electrical field cycling. However, it was found that after the SBT films were applied with electrical field display, the polarization reduction with time was observed. The aging rate was related to microstructure, which in turn was dependent on the film processing. The sputtering-SBT films show a slower degradation rate than MOD-SBT films. The suppressed polarization can be near-completely recovered by applying either thermal treatment above 150 degrees C or electric-field cycling. There exists a minimum required thermal energy to restore the polarization. The easy recovery exhibited by SBT films in suppressed polarization reveals that a relatively weak domain pinning may exist between domain wall and electronic defects in SBT. The SBT shows little fatigue behavior during electric field cycling but exhibits an aging phenomenon after applied electric field. (C) 2000 American Institute of Physics. [S0021-8979(00)04906-9].
An ANOVA test for the equivalency of means under unequal variances
(2000-04-28)
Chen, SY
;
Chen, HJ
;
Ding, CG
;
經營管理研究所
;
Institute of Business and Management
In this paper, we present a two-stage test procedure for testing the hypothesis that the normal means are falling into a practically indifferent zone. Both the level and the power associated with the proposed test are controllable and are completely independent of the unknown variances. Relation to a single-stage procedure is discussed when the two-stage sampling procedure cannot be completely carried through. An example and tables needed for implementation are given. (C) 2000 Elsevier Science B.V. All rights reserved.
An efficient network information model using NWS for grid computing environments
(2005)
Yang, CT
;
Shih, PC
;
Chen, SY
;
Shih, WC
;
資訊工程學系
Grid computing technologies enable large-scale aggregation and sharing of resources via wide-area networks focused on sharing computational, data, and other resources to form general-purpose services for users. In this paper, we address network information gathering and focus on providing approximate measurement models for network-related information using Network Weather Service (NWS) for future scheduling and benchmarking. We propose a network measurement model for gathering network-related information including bandwidth, latency, forecasting, error rates, etc., without generating excessive system overhead. We consider inaccuracies in real-world network values in generating approximation values for future use.
Anisotropic impurity scattering effects on T-c and H-c2 in YBa2Cu3Ox
(1999-03-01)
Lin, JY
;
Chen, SJ
;
Chen, SY
;
Chang, CF
;
Yang, HD
We have studied the impurity effects on the superconducting transition temperature T-c and the upper critical field H-c2 in electron irradiated YBa2Cu3Oy with in-plane oxygen defects and YBa2(Cu1-xZnx)(3)O-y. It is found that the effects of the same type of defects or impurities on T-c are the same regardless of the oxygen contents of the samples. Furthermore, T-c decreases slower in irradiated YBa2Cu3Oy than in YBa2(Cu1-xZnx)(3)O-y. This may be well explained by the model that the scattering due to in-plane oxygen defects is more anisotropic than that due to Zn impurities. The different behavior of the reduced slopes (dH(c2)/dT)(Tc)/(dH(c2)/dT)(Tc0) these two types of samples can also be understood in this context. [S0163-1829(99)08309-5].
Assessment of recoverable forms of sulfur particles used in bioleaching of contaminated sediments
(2003-01-01)
Chen, SY
;
Chiu, YC
;
Chang, PL
;
Lin, JG
;
環境工程研究所
The use of recoverable sulfur particles will enhance the feasibility and reduce the cost of bioleaching process. Three different forms of sulfur particles, powder, pastilles and pellets were used to study the utilization and recovery of sulfur, used as energy source for thiobacilli in the bioleaching process. The Langmuir isotherm was used to explain the adsorption equilibrium existing between the sorbed and suspended bacteria and the maximum adsorption capacity obtained from the Langmuir isotherm was utilized to determine the specific surface area of the sulfur particles. The specific surface area of sulfur particles was found to be the determining factor in the bioleaching process and not the particle size. The rates of pH reduction, sulfate production and metal solubilization increased with increasing specific surface area of the particles. The pH reduction and metal solubilization were significantly enhanced by the reuse of recovered sulfur particles. The efficiency of metal solubilization with recovered sulfur pastilles was comparable to that with sulfur powder. This study revealed the practicability of reusing the recovered sulfur pastilles in the bioleaching process. (C) 2002 Elsevier Science Ltd. All rights reserved.
Assessment of sediment toxicity by metal speciation in different particle-size fractions of river sediment
(2003)
Lin, JG
;
Chen, SY
;
Su, CR
;
環境工程研究所
;
Institute of Environmental Engineering
Mobility and toxicity of metals associated with sediments are generally affected by metal speciation and granular compositions. Due to the various speciation patterns of heavy metals in sediments, it is not reliable to assess the potential toxicity of heavy metals on the aquatic environment with the total concentrations of heavy metals in sediments. The purposes of this study were to investigate the distribution of metal speciation in different particle-size fractions of sediments collected from two rivers (the Ke-Ya River and Ell-Ren River) in Taiwan, and to assess their potential toxicity to the aquatic ecosystem. Metals in the exchangeable, carbonate-bound and Fe/Mn oxide-bound forms obtained by sequential extraction were considered to be mobile and related with anthropogenic pollution. The degree of metal pollution and potential toxicity of sediments were higher in the lower reaches of both rivers. The metal speciation in sediments had a bimodal distribution over particle-size fractions. Heavy metals were subject to accumulation in the silt/clay fraction (< 25 mum) and coarse sand (420-2,000 mum). By normalizing the sum of the exchangeable, carbonate-bound, and Fe/Mn oxide-bound metals, it suggested that the potential toxicity to the aquatic ecosystem was caused by the fine sediments as well as coarse sediments.
Bi3.25La0.75Ti3O12 thin films on ultrathin Al2O3 buffered Si for ferroelectric memory application
(2002-04-29)
Chen, SY
;
Sun, CL
;
Chen, SB
;
Chin, A
;
材料科學與工程學系
We have investigated the physical and electrical properties of Bi3.25La0.75Ti3O12 (BLT) thin films on Pt/Ti/SiO2/Si and on Al2O3(6 nm)/Si, which are used for one-transistor-one-capacitor and one-transistor ferroelectric memory, respectively. The BLT thin films on both substrates show good capacitance-voltage characteristics and the same threshold voltage shift of 1.6 V at applied +/-10 V bias. However, the leakage current of BLT on Al2O3/Si at -100 kV/cm is two orders of magnitude lower than that on Pt. The comparable memory characteristics and much reduced leakage current of BLT on Al2O3/Si are the strong advantages as compared with BLT on Pt because it is directly related to switching energy and device scaling down. (C) 2002 American Institute of Physics.
Biodegradation of di-(2-ethylhexyl) phthalate in sewage sludge
(2000)
Cheng, HF
;
Chen, SY
;
Lin, JG
;
環境工程研究所
;
Institute of Environmental Engineering
Di-(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in the production of polyvinyl chloride to impart flexibility to the product. Because of its mutagenicity and carcinogenicity, the presence of DEHP in sludge limits the application of sludge as a soil fertilizer. In this study, sludges were collected from three sewage treatment plants and thirteen wastewater treatment plants of different industries in Taiwan. A supercritical fluid extraction (SFE) was first established as an effective method for determining the concentration of DEHP in sludge. Laboratory-scale land-simulated experiments were performed to investigate the biodegradation of DEHP in sludge under various conditions (moisture, temperature, sunlight and ventilation). DEHP was found in aerobically and anaerobically digested sludges and their values significantly exceeded the restricted concentration of DEHP for sludge land application. DEHP was found to degrade in sludge under the conditions of good ventilation, sufficient sunlight and proper moisture. The indigenous microorganisms in the sludge appeared to dominate the biodegradation of DEHP in sludge. However about 70% of DEHP remained in sludge after 189 d indicating that DEHP is persistent in the environment.
Biodegradation of nitrilotriacetic acid and its metal complexes in river water
(1996)
Chen, SY
;
Lin, JG
;
Chang, HT
;
交大名義發表
;
環境工程研究所
In this work, we investigated the biodegradability of both the complexing agent (nitrilotriacetic acid, NTA) and its various metal complexes in an aquatic environment. A laboratory experiment was used to simulate the rates of biodegradation of NTA and NTA-metal (Ca, Pb, Zn, and Cu) complexes in river water. A first-order reaction was applied to describe the rates of biodegradation of NTA and NTA-metal complexes. NTA became completely degraded within 2 - 3 d after acclimation for 6 d and the rate coefficient (k) was 1.56 - 4.54 d(-1). Except Ca-NTA, all NTA-metal complexes degraded at a more smaller rate than NTA. The stabilities of these complexes are in the decreasing order Cu-NTA > Pb-NTA > Zn-NTA > Ca-NTA.
Biofunctional ZnO nanorod arrays grown on flexible substrates
(2006-06-20)
Liu, TY
;
Liao, HC
;
Lin, CC
;
Hu, SH
;
Chen, SY
A square pattern of thioctic acid self-assembled ZnO nanorod arrays was grown on a large 4-in. thermoplastic polyurethane (TPU) flexible substrate via an in situ soluthermal process at low temperature (348 K). With the addition of dimercaptosuccinic acid (DMSA), the surface chemistry forms a disordered ZnO phase, and the morphology of the ZnO- DMSA nanorods changes with various DMSA addition times. As evidenced by the Zn-2p3/2, C-1s, O-1s, S-2p, and N-1 s scans of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), DMSA and proteins were conjugated on the single crystalline ZnO nanorods. The photoluminescence (PL) spectra indicated that the optical properties of ZnO nanorod arrays were changed while the DMSA was inserted, and proteins were conjugated. Furthermore, a control test found that the ZnO nanorods show a significant improvement in sensitive characterization over the ZnO film. As another proteins (e. g., human serum albumin, HSA) were bound onto the ZnO- bovine serum albumin (BSA) nanorod arrays, an enhanced ultraviolet emission intensity was detected. On the basis of these results, one might be expected to conjugate specific biomolecules on the biofunctional ZnO nanorod arrays to detect the complementary biomolecules by PL detecting.
Bioleaching of heavy metals from contaminated sediment by indigenous sulfur-oxidizing bacteria in an air-lift bioreactor: effects of sulfur concentration
(2004-08-01)
Chen, SY
;
Lin, JG
;
環境工程研究所
;
Institute of Environmental Engineering
The effects of sulfur concentration on the bioleaching of heavy metals from the sediment by indigenous sulfuroxidizing bacteria were investigated in an air-lift reactor. Increasing the sulfur concentration from 0.5 to 5 g/l enhanced the rates of pH reduction, sulfate production and metal solubilization. A Michaelis-Menten type equation was used to explain the relationships between sulfur concentration, sulfate production and metal solubilization in the bioleaching process. After 8 days of bioleaching, 97-99% of Cu, 96-98% of Zn, 62-68% of Mn, 73-87% of Ni and 31-50% of Pb were solubilized from the sediment, respectively. The efficiency of metal solubilization was found to be related to the speciation of metal in the sediment. From economical consideration, the recommended sulfur dosage for the bioleaching of metals from the sediment is 3 g/l. (C) 2004 Elsevier Ltd. All rights reserved.
Bioleaching of heavy metals from livestock sludge by indigenous sulfur-oxidizing bacteria: effects of sludge solids concentration
(2004-01-01)
Chen, SY
;
Lin, JG
;
環境工程研究所
;
Institute of Environmental Engineering
A technologically and economically feasible process called bioleaching was used for the removal of heavy metals from livestock sludge with indigenous sulfur-oxidizing bacteria in this study. The effects of sludge solids concentration on the bioleaching process were examined in a batch bioreactor. Due to the buffering capacity of sludge solids, the rates of pH reduction, ORP rise and metal solubilization were reduced with the increase of the solids concentration. No apparent influence of solids concentration on sulfate produced by sulfur-oxidizing bacteria was observed when the solids concentration was less than 4% (w/v). A Michaelis-Menten type of equation was able to well describe the relationship between solids concentration and rate of metal solubilization. Besides,,high efficiencies of metal solubilization were achieved after 16 d of bioleaching. Therefore, the bioleaching process used in this study could be applied to remove heavy metals effectively from the livestock sludge. (C) 2003 Elsevier Ltd. All rights reserved.
Bioleaching of heavy metals from sediment: significance of pH
(2001-08-01)
Chen, SY
;
Lin, JG
;
環境工程研究所
;
Institute of Environmental Engineering
Bioleaching process, which causes acidification and solubilization of heavy metals, is one of the promising methods for removing heavy metals from contaminated sediments. The solubilization of heavy metals from contaminated sediments is governed by the sediment pH. In the present study, the significance of pH in bioleaching of heavy metals from contaminated sediment was evaluated at different solid contents of sediments in a bench-scale reactor. Results showed that a temporal change of pH in the bioleaching process was effected by the buffering capacity of the sediment particulates. The variations of pH in this bioleaching process were calculated by a modified logistic model. It was observed that solubilization of heavy metals from sediments is highly pH-dependent. In addition, a non-linear equation for metal solubilization relating pH value in the bioleaching process was established. This allows an easier and faster estimate of metal solubilization by measuring pH in the bioleaching process. (C) 2001 Elsevier Science Ltd. All rights reserved.
Characteristics of Pb(Zr0.53Ti0.47)O-3 on metal and Al2O3/Si substrates
(2001-11-01)
Sun, CL
;
Chen, SY
;
Yang, MY
;
Chin, A
;
材料科學與工程學系
We have fabricated Pb(Zr0.53Ti0.47)O-3 on Pt and Pb(Zr0.53Ti0.47)O-3 on 4 nm Al2O3/Si substrates. Although Pb(Zr0.53Ti0.47)O-3 on Pt has a larger dielectric constant and grain size than those on Al2O3/Si, the Pb(Zr0.53Ti0.47)O-3 thin films on both substrates show good capacitance-voltage characteristics and the same threshold voltage shift of similar to3.6 V. Moreover, the leakage current density of Pb(Zr0.53Ti0.47)O-3 on Al2O3/Si at -10 V is nearly three orders of magnitude lower than that of Pb(Zr0.53Ti0.47)O-3 on Pt. The comparable memory characteristics and the lower leakage current of Pb(Zr0.53Ti0.47)O-3 on Al2O3/Si are important for continuous scaling down the ferroelectric memory. (C) 2001 The Electrochemical Society.
Characterization and composition evolution of multiple-phase nanoscaled ceramic powders produced by laser ablation
(2004-10-20)
Lin, SC
;
Chen, SY
;
Cheng, SY
;
交大名義發表
;
National Chiao Tung University
Nanosized ceramic powder was prepared by laser ablation under different atmospheres using a ceramic target composed of ZrO2, TiO2, ZnO and Al2O3. Physical characteristics and microstructure of nanoparticles, including particle morphology, phase transformation, powder compositions and far-infrared emissivity, have been investigated. The laser-ablated nanoparticles exhibit two kinds of particle size distribution with 7-15 (70-90%) and 40-100 nm (10-30%). Nanoparticles synthesized at lower laser fluences show poor crystallinity but rich Zn composition. While increasing laser fluence, better crystalline nanoparticles with rich Zr composition were obtained. It was found that both composition and morphology of nanoparticles change with laser fluence. The average far-infrared emissivity of the nanoparticles varies with crystallinity of nanoparticles. (C) 2004 Elsevier B.V. All rights reserved.
Characterization of BaPbO3 and Ba(Pb1-xBix)O-3 thin films
(2002-02-17)
Sun, CL
;
Wang, HW
;
Chang, MC
;
Lin, MS
;
Chen, SY
BaPbO3 and Ba(Pb1-xBix)O-3 films made from barium 2-ethylhexanoate, lead 2-ethylhexanoate and bismuth acetate were prepared by metal-organic deposition (MOD) method on Pt/Ti/SiO2/Si substrate. The phase transition and the physical properties of these films were studied. The polycrystalline BaPbO3 phase starts to form above 600 degreesC and the Pb-excess addition would enhance the formation of single perovskite BaPbO3 phase. With increasing annealing temperature, the optimum sheet resistance 1.6 Omega sq(-1) (resistivity approximate to 1.07 x 10(-4) Omega cm) could be obtained at 750 degreesC. However, an annealing temperature over 800 degreesC causes reactions between substrate and BaPbO3 phase and results in sharp increase of resistance. On the other hand, the substitution of Pb by Bi in the Ba(Pb1-xBix)O-3 films could stabilize the perovskite phase, though the sheet resistance is raised over 10 Omega sq(-1) at x = 0.3. (C) 2002 Elsevier Science B.V. All rights reserved.