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Articles 23161 - 23190 of 27392

Full-Text Articles in Engineering

An Algorithm For Predicting Attitudes Of Floating Bodies With Arbitrary Configurations In Liquids, Jiann-Lin Chen, Chun-I Chen, Li-Ming Chu Dec 2010

An Algorithm For Predicting Attitudes Of Floating Bodies With Arbitrary Configurations In Liquids, Jiann-Lin Chen, Chun-I Chen, Li-Ming Chu

Journal of Marine Science and Technology–Taiwan

A robust and efficient algorithm is proposed to quasiunsteadily predict attitudes of floating bodies with arbitrary configurations. Numerical techniques for accuracy and computing time saving are addressed. A floating cylinder was modeled as a benchmark, by theoretical and experimental approaches, to validate the developed program. Attitudes of two kinds of floating bodies, which are a body composed of multiple objects and a submarine-like submersible, were simulated to show the feasibility of the present algorithm. Interestingly, the simulated results of a slender body, such as a cylinder or a submersible, show that the attitude variation is very sensitive to the longitudinal …

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Fast Block Motion Estimation With Edge Alignment On H.264 Video Coding, Chi-Han Chuang, Chien-Hua Su, Shyi-Chyi Cheng Dec 2010

Fast Block Motion Estimation With Edge Alignment On H.264 Video Coding, Chi-Han Chuang, Chien-Hua Su, Shyi-Chyi Cheng

Journal of Marine Science and Technology–Taiwan

This paper presents a novel block matching scheme with edge alignment strategy on H.264 video coding, which uses multiple references and multiple block sizes for motion estimation in order to improve the rate-distortion performance. In H.264, the computational complexity is linearly dependent on the number of allowed reference frames and block sizes using the full exhaustive search. Many fast block-matching algorithms reduce the computational complexity of motion estimation by carefully designing the search patterns with different shapes or sizes which have significant impact on the search speed and distortion performance. However, the search speed and the distortion performance conflict often …

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Investigation On Vibration Energy Flow Characteristics In Coupled Plates By Visualizaiton Techniques, Kai Li, Sheng Li, De-You Zhao Dec 2010

Investigation On Vibration Energy Flow Characteristics In Coupled Plates By Visualizaiton Techniques, Kai Li, Sheng Li, De-You Zhao

Journal of Marine Science and Technology–Taiwan

The transmission and distribution of vibration energy flow in coupled plates are studied by the vibration intensity method together with visualization technique. Formulations for vibration intensity calculations and streamline representation, and the equations for energy flow are presented. The intensity vector, streamline map and energy distribution of coupled plates subject to a point force excitation are calculated and visualized to predict vibration energy transmission. The vibrational energy flows are very complex and dependent on the excitation frequencies, junction forms and boundaries. The energy sources, sinks, transmission paths and vortex fields are clearly shown with visualization technique. It is shown that …

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Cooperation-Competition Model Of Transportation Construction Project From The Viewpoint Of Budget Allocation, Maw-Cherng Lin, Edward Ming-Yang Wu, Junn-Yuan Teng, Wen-Chih Huang Dec 2010

Cooperation-Competition Model Of Transportation Construction Project From The Viewpoint Of Budget Allocation, Maw-Cherng Lin, Edward Ming-Yang Wu, Junn-Yuan Teng, Wen-Chih Huang

Journal of Marine Science and Technology–Taiwan

Department of Marine Engineering, National Taiwan Ocean University, Keelung 202, Taiwan.

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Corrosion Assessment Of Carbon Steel In Thailand By Atmospheric Corrosion Monitoring (Acm) Sensors, W Pongsaksawad, E Viyanit, S Sorachot, T Shinohara Dec 2010

Corrosion Assessment Of Carbon Steel In Thailand By Atmospheric Corrosion Monitoring (Acm) Sensors, W Pongsaksawad, E Viyanit, S Sorachot, T Shinohara

Journal of Metals, Materials and Minerals

Atmospheric corrosion of metal depends on material compositions, weather condition (dry, dew, and rain period), temperature, relative humidity, and airborne sea salt of specific location. General testing procedure to obtain the corrosion rate is by actual exposure test of the specimen panels based on time interval plan. In Japan, atmospheric corrosion monitoring (ACM) sensor, made of an iron-silver galvanic couple, has been developed and used to sense the corrosivity in terms of galvanic current. Under some atmospheric conditions, these data can be converted to time of wetness and related to the corrosion rate of carbon steel. With ACM sensors, it …

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Postures Féminines Dans L’Oeuvre De Calixthe Beyala, Carmen Husti-Laboye Dec 2010

Postures Féminines Dans L’Oeuvre De Calixthe Beyala, Carmen Husti-Laboye

Présence Francophone: Revue internationale de langue et de littérature

The aim of this paper is to analyze, through the example of the feminist positions proposed by Calixthe Beyala in the novels she wrote between 1987 and 2007, the change of the novelist’s ideological and artistic perspective. It emphasizes the progressive loss of critical voice to the advantage of a new voice wishing to understand itself as individuality in its world. This study reveals the novelist’s contribution to the construction of a new position of the individual in the context of French social and cultural life.

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The Changing Patterns Of Internet Usage, Christopher S. Yoo Dec 2010

The Changing Patterns Of Internet Usage, Christopher S. Yoo

Federal Communications Law Journal

Symposium: Essays from Time Warner Cable's Research Program on Digital Communications.

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The Challenge Of Increasing Broadband Capacity, Dale N. Hatfield Dec 2010

The Challenge Of Increasing Broadband Capacity, Dale N. Hatfield

Federal Communications Law Journal

Symposium: Essays from Time Warner Cable's Research Program on Digital Communications.

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Petroleum Industry Linkages And Nigeria's Economic Development, Chinyere U. Nwolisa, Chinyelu N. Ugoji Dec 2010

Petroleum Industry Linkages And Nigeria's Economic Development, Chinyere U. Nwolisa, Chinyelu N. Ugoji

Bullion

Nigeria, Africa's most populous country and potentially its largest economy, has witnessed decades of dictatorship and misrule. Accompanying this misrule are severe economic problems of an unprecedented magnitude. This paper intends to add further clues to the solution for this national developmental puzzle. The remaining part of the paper is arranged thus: Part 2 presents an overview of the Nigerian Petroleum industry while the part 3 looks at the literature of economic development the country appears to be executing. Parl4 discusses the various linkages the Petroleum industry offers visa-vis Nigeria's exploration of their potentials. The penultimate part will offer some …

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Effect Of Temperature And Pressure On The Densification Of Titanium Silicide Compound, P Thapnuy, S Larpkiattaworn, T Luangvaranunt, J Ikeuchi Dec 2010

Effect Of Temperature And Pressure On The Densification Of Titanium Silicide Compound, P Thapnuy, S Larpkiattaworn, T Luangvaranunt, J Ikeuchi

Journal of Metals, Materials and Minerals

Titanium silicide compound was synthesized from the mixture of titanium and silicon powder with atomic ratios of 60:40 and 70:30. The powders were mixed by ball milling and pressed by different methods: by using uniaxial pressing at 64 MPa, cold isostatic pressing (CIP) at 200 MPa, hot forging (HF) at 648 MPa, and hot pressing (HP) at 24 MPa. The samples were then sintered at 1300o C or 1600o C for 2 hours soaking time in argon atmosphere. The sintered samples were subsequently characterized for phase constitution using X-ray diffraction (XRD). Ti5Si3 was observed as main compound of mixtures with …

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Effects Of Aluminium On Sintered Properties Of Cu-10wt%Sn Bearing, V Chobaomsup, T Luangvaranunt Dec 2010

Effects Of Aluminium On Sintered Properties Of Cu-10wt%Sn Bearing, V Chobaomsup, T Luangvaranunt

Journal of Metals, Materials and Minerals

Self-lubricating bearings are one of the oldest industrial applications of porous powder metallurgy parts, dating back to the mid-1920s. They remain the highest part produced by the P/M industry. The objective of this research was to study the effects of sintering time, sintering temperature and ratio of adding aluminium on sintered properties of Cu-10wt%Sn bearing that was produced from powder metallurgy processing. Various physical and mechanical properties such as density, percentage of porosity and hardness were tested to elucidate the effect of processing parameters. Phase identification and microstructure were analyzed by X-Ray Diffractometer and optical microscope, respectively. Sintering times in …

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Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk Dec 2010

Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk

Journal of Metals, Materials and Minerals

The tetrabutylammonium salt of Co-substituted heteropolytungstate, [(n-C4H9)4N]4 HPW11Co(H2O)O39.3H2O was synthesized and characterized. It was shown to be an active catalyst for the oxidation of cyclohexane and ethylbenzene. The oxidation reactions were performed using green oxidant hydrogen peroxide and acetonitrile as solvent. The major products of the oxidation of cyclohexane were cyclohexanone (K) and cyclohexanol (A). High selectivity towards K-A oil was achieved. At longer time cyclohexanol was converted to cyclohexanone. Ethylbenzene was also selectively oxidized to acetophenone. These oxidation reactions appear to be radical processes since they were totally inhibited in the presence of radical scavenger.

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Versatile Route For Preparation Of Polydiacetylene/Zno Nanocomposites And Their Colorimetric Response To Ph And Ethanol, N Rungruangviriya, N Traiphol Dec 2010

Versatile Route For Preparation Of Polydiacetylene/Zno Nanocomposites And Their Colorimetric Response To Ph And Ethanol, N Rungruangviriya, N Traiphol

Journal of Metals, Materials and Minerals

This contribution presents a simple method to prepare polydiacetylene(PDA)/ZnO nanocomposites, which can be utilized as active materials in sensing technology. The ZnO nanoparticles, which constitute of Zn-OH2 + , Zn-OH and Zn-O- groups at their surfaces, function as nano-substrates for self-assembling of diacetylene monomers, 10,12-pentacosadiynoic acid (PCDA), in aqueous medium. Photopolymerization of the assemblies yields poly(PCDA)/ZnO nanocomposites with core-shell structure. Strong interactions between the active groups at ZnO surface and carboxylic head groups of poly(PCDA) promote chain ordering and reduce segmental dynamics of poly(PCDA) in the nanocomposites. The existence of strong interfacial interaction drastically affects the colorimetric response behavior of …

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Study On Flame Retardancy And Anti-Dripping Of Polyester Fabric Treated With Bentonite, Diammonium Hydrogen Phosphate And Aluminium Hydroxide, P Lerdkajornsuk, S Charuchinda Dec 2010

Study On Flame Retardancy And Anti-Dripping Of Polyester Fabric Treated With Bentonite, Diammonium Hydrogen Phosphate And Aluminium Hydroxide, P Lerdkajornsuk, S Charuchinda

Journal of Metals, Materials and Minerals

The purpose of this research was to improve flame retardancy and anti-dripping of polyester fabric by using bentonite, 3% (w/w) diammonium hydrogen phosphate (DA) and 5, 10% (w/w) aluminium hydroxide (Al(OH)3) via pad-dry technique. The burning behavior of the treated polyester fabric was investigated according to ASTM D1230. The results showed that 10wt% of bentonite alone were capable of imparting anti-dripping. Nevertheless, the preparation of the slurry of bentonite (>10% (w/w)) caused high viscosity leading to difficulties for the preparation and finishing process. Thus, the addition of 4% (w/w) of sodium chloride (NaCl) to the suspension of bentonite (up …

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Pickling Behavior Of Aisi 304 Stainless Steel In Sulfuric And Hydrochloric Acid Solutions, W Homjabok, S Permpoon, G Lothongkum Dec 2010

Pickling Behavior Of Aisi 304 Stainless Steel In Sulfuric And Hydrochloric Acid Solutions, W Homjabok, S Permpoon, G Lothongkum

Journal of Metals, Materials and Minerals

Oxide scales as well as a Cr-depleted layer, which grows between the oxide scale and base metal, are formed on AISI 304 stainless steel surface during high temperature processing. Pickling is an important process which includes mechanical and chemical operations to remove oxide scales, Cr-depleted layers, and to recover the surface passivity. The multi-step pickling is commonly used because of its higher efficiency than a single step pickling. In this study, the multi-step pickling of AISI 304 stainless steel in HCl solution was investigated instead of H2SO4 solution for the first step of pickling. HF+HNO3 mixed acid is traditionally used …

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Development Of An Aluminum Semi-Solid Extrusion Process, T Rattanochaikul, S Janudom, N Memongkol, J Wannasin Dec 2010

Development Of An Aluminum Semi-Solid Extrusion Process, T Rattanochaikul, S Janudom, N Memongkol, J Wannasin

Journal of Metals, Materials and Minerals

Semi-solid extrusion process is a new forming process that is quite promising because the process requires lower forming pressure than conventional solid extrusion. In addition, semi-solid extrusion does not require large machines, which results in lower production costs. The aim of this article is to study the feasibility of an aluminum semi-solid extrusion process. The semi-solid technique selected for usage in this study was the Gas Induced Semi-Solid (GISS) process. The laboratory extrusion system was developed in this work. In the experiments, nitrogen gas was injected into aluminum melt for about 5 seconds. After that, the obtained semi-solid slurry was …

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Development Of Layered Zn-Fe Coatings For Better Corrosion Protection, R S. Bhat, R Udupak, A C. Hegde Dec 2010

Development Of Layered Zn-Fe Coatings For Better Corrosion Protection, R S. Bhat, R Udupak, A C. Hegde

Journal of Metals, Materials and Minerals

In this research, the Zn-Fe coating having successive layers of alloys of two different compositions were developed alternatively on mild steel for better corrosion protection. The multilayer coatings, or alternatively, composition modulated alloy (CMA) coatings of different configurations have been developed, and their corrosion behaviors were evaluated by electrochemical DC and AC methods. The cyclic cathode current densities and numbers of layers have been optimised for peak corrosion stability of the coatings. Under optimal condition, the CMA coating having 300 layers, having about 67 nm average thickness was found to be approximately six times higher corrosion resistant than monolayer coating …

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Effect Of Sintering On Microstructure And Properties Of Hydroxyapatite Produced By Different Synthesizing Methods, N Monmaturapoj, C Yatongchai Dec 2010

Effect Of Sintering On Microstructure And Properties Of Hydroxyapatite Produced By Different Synthesizing Methods, N Monmaturapoj, C Yatongchai

Journal of Metals, Materials and Minerals

The aim of this study is to investigate the effect of the sintering schedule on microstructure and properties of hydroxyapatite which is produced by different synthesizing methods. Hence, wet-chemical precipitation and solid-state reaction were performed to prepare nano-sized hydroxyapatite (HA) powders. Powders were then uniaxially pressed and sintered by varying temperatures and times. XRD and SEM were used to identify phases and morphology. Density and porosity of the sintered sample were determined using the Archimedes technique. Flexural strength was measured by a universal testing machine. The results show that density and strength could be improved by increasing the sintering temperature …

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Hardness And Fracture Toughness Of Alumina-Based Particulate Composites With Zirconia And Strontia Additives, T Oungkulsolmongkol, P Salee-Art, W Buggakupta Dec 2010

Hardness And Fracture Toughness Of Alumina-Based Particulate Composites With Zirconia And Strontia Additives, T Oungkulsolmongkol, P Salee-Art, W Buggakupta

Journal of Metals, Materials and Minerals

This project aims to study characteristics and mechanical properties i.e. hardness and fracture toughness of alumina matrix composite materials containing zirconia and strontium oxide. Two groups of composite specimen were fabricated: (i) Al2O3 matrix with 3 mol% Y2O3- ZrO2, varied from 10, 20, 30 and 40 vol%, and (ii) Al2O3 matrix with 2, 5, 10 and 15 vol% SrO added in the form of SrCO3. The powders were blended and then pressed into pellets. The compacts were pressureless sintered at 1600 o C for 2 hours in air. Density measurement of the sintered composites was carried out using liquid immersion. …

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Preparation And Properties Of Superhydrophobic Cotton Fabrics, P Kampeerapappun, K Visatchok, D Wangarsa Dec 2010

Preparation And Properties Of Superhydrophobic Cotton Fabrics, P Kampeerapappun, K Visatchok, D Wangarsa

Journal of Metals, Materials and Minerals

In this study, superhydrophobic cotton fabric was prepared by coating maleic-anhydride grafted poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-g-MA) triblock copolymer solutions containing calcium carbonate (CaCO3) particles. SEBS-g-MA solutions were prepared using single solvent (toluene and tetrahydrofuran (THF)) and mixed solvent (toluene: ethanol (EtOH) and THF: EtOH). Cotton fabrics were treated with the prepared solution using padding technique. All coated fabrics exhibited a water contact angle (WCA) of more than 100°. Optimum WCA values were observed when THF and 90:10 toluene: EtOH were employed. In case of CaCO3 particles addition, 6% W/V CaCO3 could impart the highest WCA value of 154°. However, the durability of …

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Surface Modification Of Polyester Fabrics With Vinyltriethoxysilane, B Kusuktham Dec 2010

Surface Modification Of Polyester Fabrics With Vinyltriethoxysilane, B Kusuktham

Journal of Metals, Materials and Minerals

Surface modification of polyester fabrics was studied aiming at improving the water repellency property. Vinyltriethoxysilane (VTES) was employed as surface modifying agent. Prior to application, VTES was prepared in aqueous emulsion using cetyltrimethylammoniun bromide (CTAB) as an emulsifying agent. The application of VTES emulsion was carried out using a padder and followed by curing at 150° C for 15 minutes. The result showed that the treated fabrics exhibited higher contact angle values when compared to untreated fabric, indicating an increase in water repellency property. It was believed that VTES was converted into silicone through siloxane network. The presence of a …

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Preparation And Characteristics Of Galangal Essential Oil/Alginate Microcapsules, T Jiamrungraksa, S Charuchinda Dec 2010

Preparation And Characteristics Of Galangal Essential Oil/Alginate Microcapsules, T Jiamrungraksa, S Charuchinda

Journal of Metals, Materials and Minerals

Galangal essential oil/alginate microcapsules were prepared by solidifying in liquid (orifice method) between sodium alginate and calcium chloride. The structure, morphology and also the thermal stability of the microcapsules were investigated by FT-IR, optical microscope, infrared moisture determination balance (IMDB) at 120°C for 2 hours. The galangal essential oil release content of microcapsules was estimated by measuring time course of weight of microcapsules determination by isothermal TGA at 37°C and 120°C. FT-IR spectral data confirmed the presence of galangal essential oil in the prepared microcapsules. An increase of sodium alginate concentration and oil content resulted in significantly higher average size …

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Study On Preparing Technology And Corrosion Resistance Of Ti/Zr Based Chromium-Free Chemical Conversion Coating On Zinc Electroplating Layer, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan Nov 2010

Study On Preparing Technology And Corrosion Resistance Of Ti/Zr Based Chromium-Free Chemical Conversion Coating On Zinc Electroplating Layer, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan

Journal of Electrochemistry

In this paper,we obtained environmental-friendly chromium-free chemical conversion coating on the non-cyanide alkaline zinc electroplating layer by employing the optimized Ti/Zr based conversion technique.At the same time,the performances of the Ti/Zr based conversion coating were compared with chromate colour passivation coating.The corrosion resistances of the conversion coatings were investigated by using neutral salt spray(NSS) test,potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The results showed that the white rust appeared after 96 hours when the NSS test was performed on the Ti/Zr based conversion coating,which was close to the corrosion resistance rating of chromate colour passivation coating.Compared with the chromate passivation coating,the Ti/Zr …

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The Sol-Gel Synthesis And Electrochemical Performance Of Li3V2(Po4)3/C Cathode Material For Lithium Ion Battery, Li-Ying Liu, Lian Chen, Hai-Yan Zhang, Yu-Chun Zhai Nov 2010

The Sol-Gel Synthesis And Electrochemical Performance Of Li3V2(Po4)3/C Cathode Material For Lithium Ion Battery, Li-Ying Liu, Lian Chen, Hai-Yan Zhang, Yu-Chun Zhai

Journal of Electrochemistry

Li3V2(PO4)3/C was synthesized by sol-gel method with citric acid as chelate and C sources. Physical and electrochemical performances of as-prepared materials were characterized through XRD, SEM and galvanostatic charge-discharge tests,etc. The results showed that products produced by calcining at 800 ℃ for 12 h had a single phase crystal structure and relatively small particle sizes with uniform distribution. At 0.1 C, 0.5 C and 1 C, the initial specific discharge capacities were 153.0, 143.1 and 130.6 mAh·g-1, respectively, and capacity efficiencies were 93.1%, 85.4% and 77.3% after 50 cycles, respectively. …

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The Roles Of The Width Of Gas/Liquid/Solid Three-Phase Boundary Zone Of Dispersion Water Films In Atmospheric Corrosion Of Metals, Jia Wang, Jing Jiang Nov 2010

The Roles Of The Width Of Gas/Liquid/Solid Three-Phase Boundary Zone Of Dispersion Water Films In Atmospheric Corrosion Of Metals, Jia Wang, Jing Jiang

Journal of Electrochemistry

The roles of TPB(Three-Phase Boundary) width in the corrosion processes of metals under dispersed water films were investigated by electrochemical techniques combined with contact angle measurement.It is found that both cathodic limiting current density and corrosion current density linearly increases with increasing the TPB width,confirming the important role of TPB width in gas/liquid/solid multiphase corrosion systems.Based on above results,the effect of water film thickness on atmospheric corrosion rate was quantitatively evaluated by the TPB width.

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Photoelectrochemical Properties Of N, S, And Cl Modified Nano Tio2 Thin Films, Hong Yun, Chang-Jian Lin, Jing Li, Rong-Gui Du Nov 2010

Photoelectrochemical Properties Of N, S, And Cl Modified Nano Tio2 Thin Films, Hong Yun, Chang-Jian Lin, Jing Li, Rong-Gui Du

Journal of Electrochemistry

The nitrogen(N),sulfur(S) and chlorine(Cl) modified nano TiO2 thin films were prepared by adding Ti(O-n-Bu)4 as the precursor into concentrated HNO3,H2SO4 and HCl Solutions,respectively,on different substrates in a sol-gel process.The photoelectrochemical performances of N,S and Cl modified nano TiO2 thin films have been studied by UV-vis(DRS),photocurrent curves,EIS and OCP-time curves.N-modified TiO2 nano films show better surface structure,which helps to improve the quantum efficiency of nano TiO2 thin films.

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Corrosion Electrochemical Behavior Of Am60 Magnesium Alloys In Automobile Engine Coolants, Ling-Jie Li, Sha Wang, Yin Xiao, Jun Lan, Jing-Lei Lei, Sheng-Tao Zhang, Fu-Sheng Pan Nov 2010

Corrosion Electrochemical Behavior Of Am60 Magnesium Alloys In Automobile Engine Coolants, Ling-Jie Li, Sha Wang, Yin Xiao, Jun Lan, Jing-Lei Lei, Sheng-Tao Zhang, Fu-Sheng Pan

Journal of Electrochemistry

The polarization measurements and electrochemical impedance spectroscopy(EIS) were used to study the corrosion electrochemical behavior of AM60 magnesium alloys in three kinds of commercial coolants for automobile engine.Results show that the tested commercial coolants are slightly corrosive to AM60 magnesium alloys and their corrosivity varies from coolant to coolant.The coolant C is the least corrosive among the studied commercial coolants and the coolant A is more corrosive than the coolant B and C.The coolant C appears to be the most promising coolant for automobile engine made by magnesium alloys.The coolant resistivity plays an important role in the corrosion of AM60 …

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Electrochemical Detection For The Corrosion Of Reinforcing Steel In Concrete During Immersion And Drying Cycles, Bing-Li Jia, Fa-He Cao, An-Na Chen, Jian-Qing Zhang Nov 2010

Electrochemical Detection For The Corrosion Of Reinforcing Steel In Concrete During Immersion And Drying Cycles, Bing-Li Jia, Fa-He Cao, An-Na Chen, Jian-Qing Zhang

Journal of Electrochemistry

The corrosion behavior of reinforcing steel in concrete under dry-wet cycle condition has been studied by electrochemical noise(EN) compared with the electrochemical impedance spectroscopy(EIS),SEM micrographs and EDS.The statistical method has been employed to analyze the EN data of reinforcing steel in concrete,which revealed three different corrosion stages of reinforcing steel in concrete,including the dissolution of the passive film,the active corrosion and the cumulation of corrosion product.The wavelet transform has also been employed,which indicated that steel in concrete with pH 1 is associated with uniform corrosion,while steel in concrete with pH 3 and pH 7 are associated with localized corrosion,such as …

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Preparation And Characterization Of The Silane-Phosphonic Acid Composite Passivation Coating For Electrogalvanized Steel, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan Nov 2010

Preparation And Characterization Of The Silane-Phosphonic Acid Composite Passivation Coating For Electrogalvanized Steel, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan

Journal of Electrochemistry

A new silane-phosphonic acid composite passivation coating process has been developed for the protection of electrogalvanized steel based on N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane(AAPTMS),γ-(2,3-epoxypropoxy)propyltrimethoxy-silane(GPTMS) and 1-hydroxy ethylidene-1,1-diphosphonic acid(HEDP).The results of X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),potentiodynamic polarization scan,electrochemical impedance spectroscopy(EIS) and neutral salt spray(NSS) tests indicated that the major structure of the prepared silane-phosphonic acid composite passivation coating consisted mainly of Si—O—Si and Si—O—P bonds.The area of white rust was not more than 5% of the total panal after 120 h NSS test,which could be compared favourably with the chromate colour passivation coating.However,the corrosion reaction on the anode of the silane-phosphonic acid composite passivation …

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Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang Nov 2010

Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang

Journal of Electrochemistry

This study detailed the atmospheric corrosion behaviour of sintered NdFeB(M35) in a simulated marine atmosphere with 80% relative humidity(RH).The dissolution and subsequent reaction of NaCl particles cause the attack of NdFeB.The corrosion presented three representative types:if the electrolyte covered magnetic phase and Nd-rich phase,the Nd-rich phase was corroded firstly due to galvanic effect;if the electrolyte covered magnetic phase,magnetic phase was corroded along the grain boundary;if the electrolyte located near the position of defects,corrosion progressed along with the defect because of low concentration of oxygen inside the defect.With corrosion progressing,local corrosion areas were mutually connected,with Nd-rich phase and grain boundary being …

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