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2003

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Articles 751 - 780 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Face Recognition Using Principal Component Analysis, Timothy Kevin Larkin Aug 2003

Face Recognition Using Principal Component Analysis, Timothy Kevin Larkin

Theses

Current methods of face recognition use linear methods to extract features. This causes potentially valuable nonlinear features to be lost. Using a kernel to extract nonlinear features should lead to better feature extraction and, therefore, lower error rates. Kernel Principal Component Analysis (KPCA) will be used as the method for nonlinear feature extraction. KPCA will be compared with well known linear methods such as correlation, Eigenfaces, and Fisherfaces.


Synthesis And Application Of Novel Chiral Ionic Liquids Derived From Alpha-Pinene, Yun Wang Aug 2003

Synthesis And Application Of Novel Chiral Ionic Liquids Derived From Alpha-Pinene, Yun Wang

Theses

Two new chiral ionic liquids of oxazolinium cations derived from a-pinene: 9,9-Dimethyl-4-propenyl-5-propyl-3 -oxa-5-azonia-tricyclo [6.1.1.0 2,6] dec-4-ene tetrafluoro borate ([ChIPOZ] [BF4]) and 9,9-Dimethyl-4-propenyl-5-propyl-3-oxa-5-azonia-tricyclo [6.1.1.0 2,6] dec-4-ene hexafluoro phosphate ([ChIPOZ][PF6]). Both these chiral ionic liquids have been applied in enantiomeric copper-catalyzed 1,4-addition reactions with diethyl zinc. The enantiomeric excess for product using [ChIPOZ][BF4] is above 70% and for [ChIPOZ][PF6] is above 30%. Chiral ionic liquids worked as phase transfer catalysts In this reaction.

α-Pinene was used as the "chiral pool" in the synthesis of amino alcohol through a two-step reaction, followed by …


Growth Of Well-Defined Zno Microparticles By Hydroxide Ion, Ruth Mcbride, Declan Mccormack, John Kelly Aug 2003

Growth Of Well-Defined Zno Microparticles By Hydroxide Ion, Ruth Mcbride, Declan Mccormack, John Kelly

Articles

The morphology of the microcrystalline zinc oxide formed by reaction of zinc salts with sodium hydroxide depends critically on the reaction conditions. To understand this, the nature of the solid product has been probed by scanning electron microcopy (SEM) and X-ray diffraction (XRD) and the concentration of zinc remaining in the solution has been determined at regular intervals throughout the reaction. Two general preparative procedures have been followed. The first, which involves simply heating an aqueous solution containing Zn(NO3)2 (0.025 M) and sodium hydroxide (0.375 M) to 101 uC and maintaining it at that temperature for periods of up to …


An Experimental Study On Network Intrusion Detection Systems, Peng Fu Aug 2003

An Experimental Study On Network Intrusion Detection Systems, Peng Fu

Theses

A signature database is the key component of an elaborate intrusion detection system. The efficiency of signature generation for an intrusion detection system is a crucial requirement because of the rapid appearance of new attacks on the World Wide Web. However, in the commercial applications, signature generation is still a manual process, which requires professional skills and heavy human effort. Knowledge Discovery and Data Mining methods may be a solution to this problem. Data Mining and Machine Learning algorithms can be applied to the network traffic databases, in order to automatically generate signatures.

The purpose of this thesis and the …


Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Fourth Quarterly Report 06/01/2003-08/30/2003, Samir Moujaes, Yitung Chen Aug 2003

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Fourth Quarterly Report 06/01/2003-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …


Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Annual Report -Phase Ii 09/01/2002-08/30/2003, Samir Moujaes, Yitung Chen Aug 2003

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Annual Report -Phase Ii 09/01/2002-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …


Cross-Calibration Of Stroke Disability Measures: Bayesian Analysis Of Longitudinal Ordinal Categorical Data Using Negative Dependence, Giovanni Parmigiani, Heidi W. Ashih, Gregory P. Samsa, Pamela W. Duncan, Sue Min Lai, David B. Matchar Aug 2003

Cross-Calibration Of Stroke Disability Measures: Bayesian Analysis Of Longitudinal Ordinal Categorical Data Using Negative Dependence, Giovanni Parmigiani, Heidi W. Ashih, Gregory P. Samsa, Pamela W. Duncan, Sue Min Lai, David B. Matchar

Johns Hopkins University, Dept. of Biostatistics Working Papers

It is common to assess disability of stroke patients using standardized scales, such as the Rankin Stroke Outcome Scale (RS) and the Barthel Index (BI). The Rankin Scale, which was designed for applications to stroke, is based on assessing directly the global conditions of a patient. The Barthel Index, which was designed for general applications, is based on a series of questions about the patient’s ability to carry out 10 basis activities of daily living. As both scales are commonly used, but few studies use both, translating between scales is important in gaining an overall understanding of the efficacy of …


Structural Requirements For Expression Of Factor Va Activity, Michael Kalafatis, Daniel O. Beck, Kenneth G. Mann Aug 2003

Structural Requirements For Expression Of Factor Va Activity, Michael Kalafatis, Daniel O. Beck, Kenneth G. Mann

Chemistry Faculty Publications

Thrombin activated factor Va (factor VIIa, residues 1-709 and 1546-2196) has an apparent dissociation constant (Kd,app) for factor Xa within prothrombinase of approximately 0.5 nM. A protease (NN) purified from the venom of the snake Naja nigricollis nigricollis, cleaves human factor V at Asp697, Asp1509, and Asp1514 to produce a molecule (factor VNN) that is composed of a Mr 100,000 heavy chain (amino acid residues 1-696) and a Mr 80,000 light chain (amino acid residues 1509/1514-2196). Factor VNN, has a Kd,app for factor Xa of 4 nm and reduced clotting activity. Cleavage of factor VIIa by NN at Asp697 results …


Breakdown Ofwave Diffusion In 2d Due To Loops, Matt M. Haney, Roel Snieder Aug 2003

Breakdown Ofwave Diffusion In 2d Due To Loops, Matt M. Haney, Roel Snieder

Matthew M. Haney

The validity of the diffusion approximation for the intensity of multiply scattered waves is tested with numerical simulations in a strongly scattering 2D medium of finite extent. We show that the diffusion equation underestimates the intensity and attribute this to both the neglect of recurrent scattering paths and interference within diffusion theory. We present a theory to quantify this discrepancy based on counting all possible scattering paths between point scatterers. Interference phenomena, due to loop paths, are incorporated in a way similar to coherent backscattering.


Synthesis And Electrochemical Properties Of K_2feo_4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song Aug 2003

Synthesis And Electrochemical Properties Of K_2feo_4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The K 2FeO 4 used for new positive electrode materials was prepared. The primary batteries were used in different concentration of electrolyte and different currents. In 9 mol/L KOH , the capacity was the best. The higher the concentration of electrolyte, the lower the electric potential was. When the batteries discharged in 0.4 C , the capacity reached 521.3 mAh/g. By XRD, we gave the reasonable explanations for the discharge products of K 2FeO 4. Possible mechanism of discharge is discussed.


Fabrication Of Scanning Micro Cl~- Probe And In Situ Imaging Of Cl~- At The Interface Of 2024 Al Aloy/Solution, Yu-Hua Lin, Min-Hua Shao, Rong-Gang Hu, Yan Li, Rong-Gui Du, Chang-Jian Lin Aug 2003

Fabrication Of Scanning Micro Cl~- Probe And In Situ Imaging Of Cl~- At The Interface Of 2024 Al Aloy/Solution, Yu-Hua Lin, Min-Hua Shao, Rong-Gang Hu, Yan Li, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Micro combination Ag/AgCl electrode with a tip measuring tens micron in diameter was fabricated. The probe satisfied in situ imaging of Cl - distribution at metal surface in chloride solution because of its excellent linearity between potential and Cl - concentration, rapid response, good stability and selectivity. With the aid of the home made Micro Electrode Scanning system and scanning Cl - probe, the effect of the [Cl - ] at 2024_Al/solution interface on localized corrosion process was investigated. It was demonstated directly that Cl - ion in solution immigrated toward, then adsorbed preferentially and accumulated at the junction between …


An Electrochemical Prediction Method For Caustic Scc Of Fe-Cr-Ni Alloy, Chun-Bo Huang, Zhan-Peng Lv, Wu Yang Aug 2003

An Electrochemical Prediction Method For Caustic Scc Of Fe-Cr-Ni Alloy, Chun-Bo Huang, Zhan-Peng Lv, Wu Yang

Journal of Electrochemistry

Stress corrosion cracking (SCC) of Fe_Cr_Ni alloy (alloy 800 M) in hot concentrated caustic solution was investigated by means of tests of C_rings under controlled potentials. The steady dissolution current densities( i st ) of the plate specimens and C_rings polarized potentiostatically were measured. The simplifed steady potentiostatical curves were drawn on the basis of i st . The ratio R PD measured from i st and steady passive current density i p at low potentials ( R PD = i st / i p ) was designed as a polarization dissolution susceptibility parameter. The parameter R PD values of …


Severe Corrosivity And Its Eletrochemical Mechanism Of Seawater In Xiamen Sea Area To Al-Mg Alloys, Le-Yun Lin, Yue-Hong Zhao Aug 2003

Severe Corrosivity And Its Eletrochemical Mechanism Of Seawater In Xiamen Sea Area To Al-Mg Alloys, Le-Yun Lin, Yue-Hong Zhao

Journal of Electrochemistry

The surface layer seawater of different sea areas in China exhibit different corrosivity to Al_Mg alloys according to the experiment results of 16 years exposure in seawater.The seawater in Xiamen sea area possesses severe corrosivity while seawater in Qingdao possesses the mildest corrosivity to Al_Mg alloys with better regularity of corrosion behavior.The present paper illustrates by experiment data that the strongest corrosivity of Xiamen seawater to Al_Mg alloys is owing to the low salinity of the seawater and the “electrolyte effect” come from it.The 16 year corrosion data and corrosion morphology of the typical Al_Mg alloys from full_immersion zone,tide zone …


Study On Adsorption Behavior Of Inhibitors On N80 Steel, Ai-Kui Li, Guo-Min Li, Xing-Peng Guo Aug 2003

Study On Adsorption Behavior Of Inhibitors On N80 Steel, Ai-Kui Li, Guo-Min Li, Xing-Peng Guo

Journal of Electrochemistry

The de_adsorption behavior of four inhibitors on N80 steel with and without carbonate film was investigated by polarization and electrochemical impedance spectroscopy (EIS) techniques. It was found that,for different inhibitors,de_adsorption behavior and adsorbability between with and without carbonate film are different.Furthermore,acidic inhibitor and small size molecule inhibitor shows different inhibition behavior.


Discussion On Factors Of Unstable 304 Stainless Steel Stress Corrosion Cracking, Xin-Sheng Zhang, Chun-Chun Xu, Gang Hu Aug 2003

Discussion On Factors Of Unstable 304 Stainless Steel Stress Corrosion Cracking, Xin-Sheng Zhang, Chun-Chun Xu, Gang Hu

Journal of Electrochemistry

The 304 stainless steels were stretched at low temperatures to get different martensite phase transformation.Ferrmagnetometer was used to measure the martensite phase content. It was found that the dislocation density of 304 stainless sted was increased unavoidably with increase of deformation.Transmission electron microscope (TEM) was used to study the distribution of the dislocation.The influence of microstructure change on SCC of 304 stainless steel was discussed by slow strain rate testing (SSRT) in 42% MgCl 2 boiling solution,metallurgical microscope and scanning electron microscope (SEM).The results showed that martensite phase and dislocation flaw act together on the SCC susceptibility of 304 stainless …


The Technique Of Rare-Earth Conversion Coatings On Aluminum Alloy, Jun-Tao Wang, Jian-Hua Wu, Guang-Zhang Chen Aug 2003

The Technique Of Rare-Earth Conversion Coatings On Aluminum Alloy, Jun-Tao Wang, Jian-Hua Wu, Guang-Zhang Chen

Journal of Electrochemistry

The orthogonal design was used to screen the film_forming technique on LY12 aluminum alloy using quadrivalent cerium salt, and the corrosion_resistance performance of the coating was studied. The results revealed that: after LY12 aluminum alloy was treated by cerium salt, its pitting potential shifts to positive direction while the corrosion potential slightly decreases, showing that the alloy becomes less sensitive to pitting corrosion was greatly improved, comparable to that after chromate treatment; in addition, by combining the results of electrochemical measurements with surface analysis, the mechanism of corrosion_resistance on the race_earth conversion coating of the aluminum alloy was also discussed.


Study On The Electrochemical Behavior Of Methy1 Green And Methy1 Green-Cyclodextrin Supramolecule System, Yu-Jing Guo, Jing-Hao Pan, Chun-Hua Guo, Hong-Lian Zheng Aug 2003

Study On The Electrochemical Behavior Of Methy1 Green And Methy1 Green-Cyclodextrin Supramolecule System, Yu-Jing Guo, Jing-Hao Pan, Chun-Hua Guo, Hong-Lian Zheng

Journal of Electrochemistry

Electrochemical behavior of methyl green in different kinds of solution and the supramolecule system of methyl green_cyclodextrin were studied.Inclusion constants of four cyclodextrin with emthyl green were determined by “electric current method”.The order of inclusion ability is HP_β_CD,β_CD,SBE_β_CD and CM_β_CD.The molar ratio of inclusion complexes of methyl green with CDs is 1:2. A possible mechanism was reported for methyl green.


Study Of Electrolyzed Pure Iron And Rrr_H Method, Wei_Min Cao, Ren-He Yin, Hui-Gen Yan, Yi-Bing Zhang, Ying-Chun Dai Aug 2003

Study Of Electrolyzed Pure Iron And Rrr_H Method, Wei_Min Cao, Ren-He Yin, Hui-Gen Yan, Yi-Bing Zhang, Ying-Chun Dai

Journal of Electrochemistry

The high purity electrolytic iron was made from scrap iron chips. The purity of electrolyzed pure iron was above 99.98% by chemical analysis. The resistivity was measured at 298 K and at 4.2 K under an applied longitudinal_magnetic field of 800 0 e. The ratio of resistivity at 298 K to that at 4.2 K, The value of residual resistivity ratio (RRR H) roughly depended on the purity of iron. Pure iron electrolyzed on Ti substrate had very compact texture as evident by SEM.


Observation Of A Narrow Resonance Of Mass 2.46 Gev/C2 Decaying To DS*+ Π0 And Confirmation Of The D*SJ (2317) State, Dave Z. Besson, Kenneth A. Bloom, Cornell Electronic Storage Ring Aug 2003

Observation Of A Narrow Resonance Of Mass 2.46 Gev/C2 Decaying To DS*+ Π0 And Confirmation Of The D*SJ (2317) State, Dave Z. Besson, Kenneth A. Bloom, Cornell Electronic Storage Ring

Kenneth Bloom Publications

Using 13.5 fb-1 of e+e- annihilation data collected with the CLEO II detector, we have observed a narrow resonance decaying to Ds*+π0 with a mass near 2.46 GeV/c2. The search for such a state was motivated by the recent discovery by the BaBar Collaboration of a narrow state at 2.32 GeV/c2, the DsJ*(2317) +, that decays to Ds+ π0. Reconstructing the Ds+ π0 and Ds*+ π0 final states in CLEO data, we …


Essays On Minimum Cost Spanning Tree Games., Anirban Kar Dr. Aug 2003

Essays On Minimum Cost Spanning Tree Games., Anirban Kar Dr.

Doctoral Theses

There is a wide range of economic contexts in which aggregate costs have to be allocated amongst individual agents or components who derive t he benefits from a common project. A firm has to allocate overheard costs atmongst its different divisions. Regulatory authorities have to set taxes or fees on individual users for a variety of services. Partners in a joint venture must share costs (and benefits) of the joint venture. For example, when two doctors share an office they need to divide the cost of office space, medical equipment and secretarial help. If several municipalities use a common water …


Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai Aug 2003

Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai

Journal of Electrochemistry

The corrosion fatigue and dynamic strain aging behaviors of 22%Cr duplex stainless steel (DSS) in sodium chloride solutions were investigated. Austenitic 316L SS and ferrtic 430 SS were also used in this study for a comparison. The experimental results showed that no stress corrosion cracking (SCC) occurred in all these SSs tested in 3.5wt% NaCl solution at 80 ℃. However, dynamic strain aging (DSA) occurred in 316L austenitic SS and 22%Cr DSS during slow strain rate testing (SSRT) in this solution.The occurrence of DSA was dependent on solution temperature,strain rate and the presence of austenitic phase. The corrosion rate of …


Comparison Of Thermal Cyclic Oxidation Of The Pvd Ni-Al And Hvof-Mcraly Coatings, Chang J.T., H. Yeh C., He J.L., Chen K.C. Aug 2003

Comparison Of Thermal Cyclic Oxidation Of The Pvd Ni-Al And Hvof-Mcraly Coatings, Chang J.T., H. Yeh C., He J.L., Chen K.C.

Journal of Electrochemistry

A PVD process_cathodic arc plasma ion plating was used to deposit Ni_Al films on Inconel 600 superalloy. The oxidation behaviors of PVD Ni_Al coating and the thermal sprayed CoCrAlY coatings were revealed and compared by performing cyclic thermal oxidation test at 1 100 ℃ to evaluate its feasibility. Experimental results showed that the films with different compositions of Ni 62 Al 38 , Ni 63 Al 37 and Ni 69 Al 31 could be obtained when using Ni 52 Al 48 , Ni 60 Al 40 and Ni 70 Al 30 as targets, respectively. During the cyclic thermal oxidation test, …


Electrochemical Response Of Deformed Marine Steel In Sea-Mud Containing Sulfate Reducing Bacteria, Yan-Liang Huang Aug 2003

Electrochemical Response Of Deformed Marine Steel In Sea-Mud Containing Sulfate Reducing Bacteria, Yan-Liang Huang

Journal of Electrochemistry

The corrosion failure behavior of marine steel is affected by stress,which exists in offshore structures at sea_mud region.In order to conduct the study of stress on the electrochemical response of a selected steel,a kind of natural sea_mud containing sulfate reducing bacteria(SRB) was collected.The electrochemical response of cyclic stress of the specimen with and without cracks in sea_mud was analyzed.


The Second Circular For 12th National Conference On Electrochemistry Of China Aug 2003

The Second Circular For 12th National Conference On Electrochemistry Of China

Journal of Electrochemistry

No abstract provided.


Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou Aug 2003

Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou

Journal of Electrochemistry

A Mannich Base derivative (BMMCH), containing two morpholinum moieties and one cyclohexylamnonium moiety, was synthesized through aminomethy1 reaction. Its configuration was verified by IR and 1H_NMR. Its volatile rustproofing effect was appraised by volatile rustproofing sieve test and vapor inhabitability test. The result shows that BMMCH has good protection effect for carbon steel. BMMCH has lower volatility compared with dicyclohexylamnonium nitrite (DICHAN) via closed space volatile weight_loss test. The inhibition mechanism was studied by potentiodynamic polarization electrochemistry technique in ASTM simulated atmospheric water. The corrosion potential of carbon steel electrode shifted to a negative direction when BMMCH was joined in. …


Effect Of Heat Laminating Aggregation Status Of Polymer Lithium-Ion Battery Cathode On Battery Performance, Ming-Gang Jin, Quan-Feng Dong, Ming-Sen Zheng, Li Huang, Hui-Qun Cai, Jin-Qua You, Zu-Geng Lin Aug 2003

Effect Of Heat Laminating Aggregation Status Of Polymer Lithium-Ion Battery Cathode On Battery Performance, Ming-Gang Jin, Quan-Feng Dong, Ming-Sen Zheng, Li Huang, Hui-Qun Cai, Jin-Qua You, Zu-Geng Lin

Journal of Electrochemistry

Multi_layer heat laminated polymer lithium ion battery was made, the effect of temperature of cathode laminating on battry performance was also investigated. It was discovered that suitable temperature of cathode laminating is critical to battery performance and is a key parameter to manufacture process control of polymer lithium ion battery.


Electrochemistry And Electrocatalysis Of A Novel Μ-Oxamido Copper(Ⅱ) Binuclear Complex, Gui-Lian Gao, Guo-Bao Li, Qiu-Xia Yang, Xue-Lin Wang Aug 2003

Electrochemistry And Electrocatalysis Of A Novel Μ-Oxamido Copper(Ⅱ) Binuclear Complex, Gui-Lian Gao, Guo-Bao Li, Qiu-Xia Yang, Xue-Lin Wang

Journal of Electrochemistry

In this paper,the cyclic voltammetric and spectroelectrochemical behaviors of μ _oxamido Copper(Ⅱ) Binuclear Complex (deCu) in PBS were studied.Cyclic voltammograms of this complex in PBS(pH=9)exhibited two reductive peaks( E pc1 =-0.25 V, E pc2 =-0.50 V)at hanging mercury drop electrode(HMDE),peaks at -0.50 V and -0.25 V corresponded to the reduction of ligand and copper(Ⅱ)_complex, respectively.The spectroelectrochimical experiments showed that there was a new absorption band at 440 nm,and the absorption peaks at 270 nm,280 nm red shifted to 300 nm,310 nm under potential of -0.75 V.It was meant that the Cu(Ⅱ) turned into low valent copper,simultaneously,a new large coupling system …


Influence Of Marine Organisms Upon Corrosion Of Steel Piling Systems, Jiunn-Shyong Luo, Cliff Cliff, Rau Rau, Kuei-Ching Chen Aug 2003

Influence Of Marine Organisms Upon Corrosion Of Steel Piling Systems, Jiunn-Shyong Luo, Cliff Cliff, Rau Rau, Kuei-Ching Chen

Journal of Electrochemistry

To study the influence of marine organisms upon corrosion of ASTM A36 steel piling sysems,specimens were immersed in both natural and synthetic seawater.Electrochemical techniques such as linear polarization resistance and electrochemical impedance scan(EIS) were applied to evaluate corrosion of the steel.The results indicated that attachment of marine organisms to form fouling layers on the steel surface reduced general corrosion,but localized corrosion occurred underneath marine organisms.An equivalent circuit model was established to simulate attachment of marine organisms upon carbon carbon steel surfaces.


The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu Aug 2003

The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu

Journal of Electrochemistry

Electroless Ni_Fe_P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH,temperature and mole ratio of [Fe 2+ ]/([Ni 2+ ]+[Fe 2+ ]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the per_centage of iron in the electroless Ni_Fe_P …


The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao Aug 2003

The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao

Journal of Electrochemistry

The oxygen electroreduction on the MnO 2 electrode was investigated by analysis of the polarzation properties of oxygen reduciton and its dependence on MnO 2 discharge state,in combination with the characterization of discharge intermediate and the kinetic parameters of the oxygen reduction.Based on the experimental observation and mechanistic analysis,it was suggested that the reduction of oxygen was closely related to the discharge behaviors of MnO 2 .When MnO 2 was electrochimically reduced to MnOOH,it was immediately oxidized by oxygen molecules. Thus the oxygen reduction proceeds through continuous oxidation of the discharge product of MnO 2 and the MnO 2 catalyst …