Taoyuan, Taiwan
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A reliable, sensitive and eco-friendly injection-port trimethylsilylated (TMS) derivatization and gas chromatography-tandem mass spectrometry (GC-MS/MS) with furan chemical ionization (furan-CI) method was developed to determine melamine and cyanuric acid in powdered milk samples. The effects of several parameters related to the TMS-derivatization process (i.e., injection-port temperature, residence time and volume of silylating agent) and of various CI agents were investigated. Addition of a solution (3 μL) of bis(trimethyl)silyltrifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane (TMCS) reagent to a 20-μL extract from the powdered milk sample gave an excellent yield of the tris-TMS-derivatives of melamine and cyanuric acid at an injection-port temperature of 90 °C. Furthermore, using furan as the CI agent in conjunction with tandem mass spectrometry provided the greatest sensitivity and selectivity of detection. The limits of quantitation (LOQs) for melamine and cyanuric acid were 0.5 and 1.0. ng/g in 0.5-g of powdered milk samples, respectively. The recoveries from spiked samples - after simple ultra-sonication with 5% dimethyl sulfoxide in acetonitrile coupled with n-hexane liquid-liquid extraction - ranged from 72% to 93% with relative standard deviations of lower than or equal to 18%. In three of four real powdered milk samples, melamine was detected at concentrations ranging from 36 to 1460. ng/g; and cyanuric acid was detected in two of these samples at concentrations of 17 and 180. ng/g. © 2010 Elsevier B.V.

Chung W.-H.,National Central University | Chung W.-H.,Army Academy ROC | Tzing S.-H.,Army Academy ROC | Ding W.-H.,National Central University
Journal of Chromatography A | Year: 2013

A simple and solvent-free method for the rapid analysis of five synthetic polycyclic musks in water samples is described. The method involves the use of dispersive micro solid-phase extraction (D-μ-SPE) coupled with direct thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) operating in the selected-ion-storage (SIS) mode. The parameters affecting the extraction efficiency of the target analytes from water sample and the thermal desorption conditions in the GC injection-port were optimized using a central composite design method. The optimal extraction conditions involved immersing 3.2. mg of a typical octadecyl (C18) bonded silica adsorbent (i.e., ENVI-18) in a 10. mL water sample. After extraction by vigorously shaking for 1.0. min, the adsorbents were collected and dried on a filter. The adsorbents were transferred to a micro-vial, which was directly inserted into GC temperature-programmed injector, and the extracted target analytes were then thermally desorbed in the GC injection-port at 337. °C for 3.8. min. The limits of quantitation (LOQs) were determined to be 1.2-3.0. ng/L. Precision, as indicated by relative standard deviations (RSDs), was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 74 and 90%. A preliminary analysis of the river water samples revealed that galaxolide (HHCB) and tonalide (AHTN) were the two most common synthetic polycyclic musks present. Using a standard addition method, their concentrations were determined to in the range from 11 to 140. ng/L. © 2013 Elsevier B.V.

Lin H.-L.,Army Academy Roc | Wu T.-M.,National Chiao Tung University
Materials and Manufacturing Processes | Year: 2012

The purpose of this work is to investigate the effects of activating fluxes and welding parameter to the penetration and depth-to-width ratio (DWR) of weld bead of Inconel 718 alloy welds in the tungsten inert gas (TIG) welding process. In the activating flux with TIG (A-TIG) welding process, the single-component fluxes used in the initial experiment were SiO2, NiO, MoO3, Cr2O3, TiO2, MnO 2, ZnO, and MoS2. Based on the higher DWR of weld bead, four fluxes were selected to create six new mixtures using 50% of each original flux. The A-TIG weldment coated 50% SiO2+50% MoO3 flux and 75° of electrode tip angle were provided with better welding performance. In addition, the experimental procedure of flux-bounded TIG (FB-TIG) welding with the same welding conditions and flux produced full penetration of weld bead on a 6.35mm thickness of Inconel 718 alloy plate with single pass weld. © 2012 Copyright Taylor and Francis Group, LLC.

Lee C.-F.,Chaoyang University of Technology | Chen H.-L.,Chaoyang University of Technology | Tso H.-K.,Army Academy Roc
Journal of Systems and Software | Year: 2010

Most of the proposed methods of reversible data hiding based on difference expansion require location maps to recover cover images. Although the location map can be compressed by a lossless compression algorithm, this lowers embedding capacity and increases computational cost during the procedures of embedding and extracting. The study presents an adaptive reversible data scheme based on the prediction of difference expansion. Since each cover pixel generally resembles its surrounding pixels, most of the difference values between the cover pixels and their corresponding predictive pixels are small; therefore, the proposed scheme gains from embedding capacity by taking full advantage of the large quantities of smaller difference values where secret data can be embedded. The proposed scheme offers several advantages, namely, (1) the location map is no more required, (2) the embedding capacity can be adjusted depending on the practical applications, and (3) the high embedding capacity with minimal visual distortion can be achieved. Moreover, the experimental results demonstrate that the proposed scheme yields high embedding capacity by comparing the related schemes that are proposed recently. © 2010 Elsevier Inc. All rights reserved.

Tang C.-W.,Army Academy Roc | Chuang S.S.C.,University of Akron
International Journal of Hydrogen Energy | Year: 2014

The water-gas shift (WGS) reaction on co-precipitated NiO-ZnO catalysts at different reduction temperatures has been studied by a temperature-programmed reaction using in situ diffuse reflectance infrared Fourier Transform Spectroscopy, coupled with mass spectroscopic (in situ DRIFTS/MS) techniques. The results reveal that a catalyst reduced at 493 K (labeled H220) showed higher activity than one reduced at 673 K (labeled H400) due to the ability of NiO on the H220 catalyst to promote CO conversion of the WGS reaction. In situ DRIFTS/MS studies show that there are three adsorbed species over the H220 catalyst at room temperature: adsorbed CO bands, molecularly adsorbed H 2O and carboxyl species. Increasing the temperature to 423 K led to the emergence of CO2 and H2 and the disappearance of carboxyl species. However, the low catalytic activity of the H400 catalyst could be attributed to the conversion of the NiO sites to reduced Ni metal sites, which (i) adsorbed CO as the strong linearly bonded CO on the catalyst surface, slowing down the CO reaction, and (ii) showed a lower H2O uptake. Copyright © 2013, Hydrogen Energy Publications, LLC.

The objective of this paper is to present an integrated approach using the Taguchi method (TM), grey relational analysis (GRA) and a neural network (NN) to optimize theweld bead geometry in a novel gas metal arc(GMA)welding process. The TM is first used to construct a database for the NN. TheGRAis adopted to solve the problem of multiple performance characteristics in aGMAwelding process using activating flux. The grey relational grade obtained from the GRA is used as the output of the back-propagation (BP) NN. Then, aNNwith the Levenberg-Marquardt BP (LMBP) algorithm is used to provide the nonlinear relationship between welding parameters and grey relational grade of each weldment. The optimal parameters of the novel GMA welding process were determined by simulating parameters using a well-trainedBPNNmodel. Experimental results illustrate the proposed approach. © Springer Science+Business Media, LLC 2010.

Lin H.-L.,Army Academy ROC
International Journal of Advanced Manufacturing Technology | Year: 2013

The purpose of this work is to optimize the weld bead geometry of Inconel 718 alloy gas tungsten arc (GTA) welds that are coated with activating flux before welding. In order to obtain the optimal welding parameters with multiple quality characteristics (QCs) such as penetration and depth-to-width ratio (DWR) of weld bead, the Taguchi method (TM), gray relational analysis (GRA), and a neural network (NN) are employed in this work. The TM is first used to construct a database for the NN. The GRA is adopted to solve the problem of multiple QCs. The gray relational grade (GRG) obtained from the GRA is used as the output of the backpropagation (BP) NN. Then, a NN with the Levenberg-Marquardt BP (LMBP) algorithm is used to provide the nonlinear relationship between welding parameters and GRG of each specimen. The optimal parameters of the activated GTA welding process are determined by simulating parameters using a well-trained BPNN model. The experimental procedure of the proposed approach not only improves the DWR of weld bead but also increases the penetration of Inconel 718 alloy welds. © 2012 Springer-Verlag London.

Lin H.-L.,Army Academy Roc
Journal of Intelligent Manufacturing | Year: 2012

This work describes an application of an integrated approach using the Taguchi method (TM), neural network (NN) and genetic algorithm (GA) for optimizing the lap joint quality of aluminum pipe and flange in automotive industry. The proposed approach (Taguchi-Neural-Genetic approach) consists of two phases. In first phase, the TM was adopted to collect training data samples for the NN. In second phase, a NN with a Levenberg-Marquardt back-propagation (LMBP) algorithm was adopted to develop the relationship between factors and the response. Then, a GA based on a well-trained NN model was applied to determine the optimal factor settings. Experimental results illustrated the Taguchi- Neural-Genetic approach. © Springer Science+Business Media, LLC 2010.

Tso H.-K.,Army Academy ROC
Nonlinear Dynamics | Year: 2014

In recent years, image sharing scheme has attracted much attention for researchers due to the characteristics of security and easy implementation. In 2011, Wang and Lee proposed a random grid-based sharing scheme with identifiable shares to protect the security of the secret images. Their method has several disadvantages that must be improved. First, the constructed shares are meaningless ones which are difficult to manage. Second, the original secret image cannot be completely recovered which can cause the misjudgment of information. Wang et al. proposed a sharing method with verification ability in 2011. However, the constructed shares are also meaningless ones. This paper proposes a meaningful image sharing scheme to improve the above-mentioned disadvantages. Furthermore, we utilize toral automorphism to enhance the security of the secret image. Experimental results can show the feasibility of the proposed method. © 2013 Springer Science+Business Media Dordrecht.

Lin Z.-C.,National Taiwan University of Science and Technology | Wang R.-Y.,Army Academy Roc
International Journal of Advanced Manufacturing Technology | Year: 2014

The paper establishes a new theoretical model for abrasive removal depth for polishing a sapphire wafer using chemical mechanical polishing with a polishing pad that has a cross pattern. The theoretical model uses binary image pixel division to calculate the pixel polishing times. An abrasive contact model for single-pixel multiple abrasive particles, to estimate the contact force between a single abrasive particle and the wafer, is then established. When the contact force is calculated, it is possible to calculate the abrasive depth of a single abrasive particle on the surface of the sapphire wafer. Using this theoretical model, carring a numerical simulation with a slurry of the same concentration, but with different abrasive particle diameters, determines the removal volume and average abrasive removal depth at each pixel position and the surface condition of the wafer. The simulation result is also compared with experimental data, in order to verify that the new model is feasible. © 2014 Springer-Verlag London.

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