Physical Sciences and Mathematics Commons^™

Accuracy And Limitations Of Localized Green’S Function Methods For Materials Science Applications, Duane D. Johnson, Andrei V. Smirnov

Duane D. Johnson

We compare screened real-space and reciprocal-space implementations of Korringa-Kohn-Rostoker electronic-structure method for their applicability to largescale problems requiring various levels of accuracy. We show that real-space calculations in metals can become impractical to describe energies. We suggest a combined r- and k-space scheme as the most efficient and flexible strategy for accurate energy calculations. Our hybrid code is suitable for (parallel) large-scale calculations involving complex, multicomponent systems. We also discuss how details of numerical procedures can affect accuracy of such calculations.

Research Progress On Proton Exchange Membranes Of Fuel Cells, Jing-Rong Yu, Dan-Min Xing, Fu-Qiang Liu, Jian-Guo Liu, Bao-Lian Yi

Journal of Electrochemistry

The proton exchange membrane fuel cells(PEMFC) use proton exchange membranes(PEM) as their electrolytes. The performance of the PEMFC is strongly dependent on the characteristics of the PEM. In this paper, the requirements of the PEM utilized in the PEMFC were analyzed. The per_fluorinated, partially fluorinated and non_fluorinated PEM were introduced respectively. The structures, preparation, properties of the various types of PEM and their applications in the PEMFC were also discussed in detail.

New Progress Of Intrinsic Conducting Polymers' Application, Wan Chen, Cheng-Hao Liang, Yang Xie

Journal of Electrochemistry

As a kind of functional polymer, the intrinsic conducting polymer has the special chemical, electrochemical and optical properties. So it has wide application such as batteries, electromagnetic wave shielding, electroluminescent etc. Recent development and the problems of the intrinsic conducting polymers' application were briefly reviewed in this paper.

Thermal Effects On The Measurement Of Photocurrent At Anodic Films On Silver Electrode, Yuan Gu, Zhi Yu Jiang

Journal of Electrochemistry

The influence of heat on the photocurrent of Ag electrode in alkaline solution was investigated by measuring photocurrent, photothermal signal and thermal current under the irraiation of laser beams with the wavelengths of 488 nm and 532 nm. It was found the photocurrent at the Ag 2O film was influenced by the temperature change at the electrode surface under the irradiation of light. During the electrochemical transfer between Ag, Ag 2O and AgO in the anodic film, the surface temperature changed obviously due to the different absorptance of the surface substances. It was suggested by comparing the voltammograms, photocurrent curves …

Corrosion Of Steel In Sea-Bottom Mud Of Nothern China Sea Area, Gong-Yu Guo, Jing-Lei Zhang, Bao-Rong Hou, Fang-Ying Yang

Journal of Electrochemistry

Corrosion experiments of A 3, 16Mn, 20 # as well as ZCE36_225 steel were carried out in southern Bohai sea and Qingdao sea areas. The sea_bottom mud in southern Bohai sea area is the sandy mud and that in Qingdao sea area is pure beach sand. In this experiment, the compareing test of two modes with electric connected and non_electric connected modes was carried out. The experiment results showed that: 1) the corrosion rate of steel in sea_bottom mud has a strong relation with mud types. The corrosion rates of steels in pure beach sand are much higher than those …

Study Of Hydrogen Diffusion Behavior In Hydrogen Storage Alloy Mlni_(3.75)Co_(0.65) Mn_(0.4) Al_(0.2) With Potential Step Method, Xian Xia Yuan, Nai Xin Xu

Journal of Electrochemistry

Potential step method was employed to study the hydrogen diffusion behavior in hydrogen storage alloy MlNi 3.75 Co 0.65 Mn 0.4 Al 0.2 with various depth of discharge(DOD) at ambient temperature and with 50%DOD at various temperatures. It was found that hydrogen diffusion cofficient in the hydrogen storage alloy increaes with the increase in DOD at ambient temperature. and for the alloy with 50%DOD,the hydrogen diffusion coefficient increases with the increase in temperature and the activation energy for hydrogen diffusion in the alloy is 19.87 kJ/mol.

Studies On The Anti-Corrosion Behavior Of Corrosion Inhibitor To The Ship Building Steel In Moist Air, Yong Tao Zhao, Jian Hua Wu, Jia Wang

Journal of Electrochemistry

The anti corrosion behavior of 907A steel, which were covered with thin inibitor layers in moist air, were simulated, The electrochemical measurements, including EIS method and the coulostatic method, were used to atmospheric corrosion monitor(ACM)under thin inhibitor layers to study the mechanism of rust preventiion. the results shown that the mechanism of inhibiting corrosion was different from the steel immersed in inhibitor solutin, the anodic reaction process under thin inhibitor layers had the advantage over that of cathodic for blocking the speed of corrosion. At the later stage of soaking, the blend feature due to the electrochemical process and the …

An Investigation Of Structural Properties Of Li-Al-Mixed Doped Spinels Materials Li_(1+X) Al_Ymn_(2-Y)O_4, Zi-Shan Zheng, Zi-Long Tang, Zhong-Tai Zhang, Wan-Ci Sheng

Journal of Electrochemistry

Al and Li elements were co_doped into host spinel lithium manganese oxide by a simple and economical preparation technology . There was an investigation of the influence of doped Al contents on the initial capacity and cycling performance of the materials. The investigation of the XRD patterns, the analysis of the SEM micrographs and the determination of IR spectroscopy showed that the particles of dopant materials are fine, narrowly distributed and well crystallized, and the bonds Mn_O are stronger than these of undoped materials. The resulted materials have a high initial capacity of 119 mAh/g and good cycling characterization. The …

Study On The Anticorrosion Of Ld-2 Compound Inhibitor On Reinforcing Steel In Seawater, Rong-Gui Du, Zhou-Cheng Wang, Ruo-Shuang Huang, Rong-Gang Hu, Bing Zhao, Jian-Guang Tan, Chang-Jian Lin

Journal of Electrochemistry

The effect of LD_2 compound inhibitor developed in our laboratory on its anticorrosion action on the reinforcing steel in concrete immersed in seawater was shown in this paper. The corrosion behavior of the reinforcing steel in seawater was studied using electrochemical techniques and immersion tests. The polarization curve of the reinforcing steel immersed in seawater showed the free corrosion potential of the steel increased by 0.220 V (vs. SCE), and the corrosion current decreased by two orders of magnitude by adding 25 g·L -1 compound inhibitor to the seawater. The potentiodynamic anodic polarization curve of reinforcing steel in the seawater …

Study On Electrochemical Behavior Of Copper In Nh_3·H_2o Solution Medium Including K_3 During Cmp, Yue Hua Hu, Han Wei He, Uang Ke Nong H

Journal of Electrochemistry

Influence of medium pH value and passivator concentrations on the copper passivation and CMP process were studied by electrochemical measurement technologies, relations of the film thickness and tightness with polishing process and polishing rates were investigated. Electrochemical variables influencing polishing process and rates were found out. Electochemical mechanism of polishing processes were explained by corrosion potential and corrosion current density. A recipe of K 3 as passivator and nano sized γ Al 2O 3 as abrasives in medium of NH 3·H 2O solution was confirmed reasonable. It is shown that the conditions of polishing process to be controlled are 10 …

The Influence Of Synthesis Conditions On The Electrochemical Properties Of Spinel Limn_2o_4, Jun Feng Xu, Zhi Yu Jiang

Journal of Electrochemistry

The electrochemical properties of spine LiMn 2O 4 synthesized via a solid state reaction were investigated. Electrolysis MnO 2(EMD), Li 2CO 3,LiOH and LiNO 3 were used as the initial materials. It was found that the electrochemical properties of LiMn 2O 4 were strongly influenced by the synthesis conditions. The LiMn 2O 4 samples prepared via the reaction of EMD and LiNO 3 showed the best properties for a lithium ion intercalation reaction. The procedure includes two steps: pretreatment at 280 ℃ for 6 hours to initiate the permeation of melting LiNO 3 into the micropores of EMD particles, followed …

Adsorption And Oxidation Of Methanol On Pt And Sb, S Modified Pt Electrodes Using Cyclic Voltammetry And Eqcm, Guo-Liang Chen, Sheng-Pei Chen, Heng Lin, Xing-Hong Zheng, Shi-Gang Sun

Journal of Electrochemistry

The processes of adsorption and oxidation of methanol on Pt, Pt/Sb ad and Pt/S ad electrodes were studied by using cyclic voltammetry and electrochemical quartz crystal microba_lance (EQCM). The results demonstrated that the oxidation of methanol depends strongly on oxidation states of electrode surface. Sb adatoms on Pt surface can adsorb oxygen at relatively low potentials, and exhibit catalytic effects for methanol oxidation. In contrast to Pt electrodes, the oxidation peak potential of methanol in this case negatively shifted to about 130 mV. In a contrary, the oxidation of S adatoms consumes oxygen species of Pt electrode surface. As a …

Electrosynthesis Of A New Electroactive Poly(2,2'-Diaminophenyloxydisulfide), Yu Zhi Su, Yan Wen Rao, Ye Yang, Mei-Bing Chen, Yin Ling Qiu, Yong-Hua Zhang, Ke Cheng Gong

Journal of Electrochemistry

A new electroactive poly(2,2' diaminophenyloxydisulfide) (PDAPD) was successfully synthesized from acetonitrile(AN)/tetrahydrofuran(THF)solutions containing the supporting electrolyte(LiClO 4)and the various kinds of acids(HCl,CF 3COOH,CCl 3COOH) on Pt electrode by consecutive cyclic voltammiry. The effects of the concentrations of supporting electrolyte(LiClO 4) and acid(HCl,CF 3COOH,CCl 3COOH) on electrodepositon of PDAPD film were investigated. The best experimental conditions for electrosynthesis of a highly electroactive conducting polymer film are that the concentrations are 0.1 mol/L and between 0.05 mol/L～0.5 mol/L,respectively for LiClO 4 and HCl.

The Research Of Organic Electrolyte Solutions For Li-Ion Batteries, Quang Chao Zhuang, Shan Wu, Wen Yuan Liu, Zhao-Da Lu

Journal of Electrochemistry

The characteristics of organic electrolyte solutions and its influences on the ion conductivity are summarized. The chemistry and electrochemistry of organic electrolyte solutions and characteristics of ordinary organic solvents are introduced. Progresses in studies of organic electrolyte solutions such as electrolyte salts, organic solvents, additives in recent years are reviewed, current situation of the studies of organic electrolyte solutions were also discussed.

The Investigation Of Prepare Condition For Micropores Membranes From Poly(Vinylidene Fluoride), Xu-Mei Ren, Feng Wu, Ying Bai, Hang-Jun Li, Xue Jie Huang

Journal of Electrochemistry

The micropores membranes from Poly (vinylidene fluoride) were prepared by the phase inversion process. The effects of the casting solution composition, exposure time prior to coagulation and temperature of the coagulation bath on properties of prepared membranes were investigated. For all prepared membranes an asymmetric structure, sometimes without a dense skin layer, was observed.

Studies On The Properties Of The Anodic Films Formed On Lead- Lanthanum And Lead-Samarium Alloys In Sulfuric Acid Solution, Hou Tian Liu, Chun Xuao Yang, Hai Heng Liang, Jiong Yang, Wei-Fang Zhou

Journal of Electrochemistry

AC voltammetry,linear sweep voltammetry,and cyclic voltammetry were applied to study the anodic corrosion of Pb,Pb 1.0at%La and Pb 1.0at%Sm electrodes in 4.5 mol·dm -3 H 2SO 4 solution (25 ℃).The experiment results show that samarium can inhibit the anodic corrosion of lead and decrease the impedance of anodic Pb(Ⅱ) film. Lanthanum can also decrease the impedance of the anodic Pb(Ⅱ)film, but the effect is smaller.

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Aaa Task-4 Quarterly (September 1 – November 30, 2001) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including HT- 9, EP 823 and 422. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these alloys will be evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. The extent and morphology of cracking of these alloys will further be evaluated …

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823: Task 10, First Quarter Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The objective of this task is to evaluate the elevated temperature tensile properties of Alloy EP-823, a leading target material for accelerator-driven waste transmutation applications. The test material will be thermally treated prior to evaluation of its tensile properties at temperatures relevant to the transmutation applications. The deformation characteristics of tensile specimens, upon completion of testing, will be evaluated by surface analytical techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall results are expected to provide a mechanistic understanding of high-temperature deformation behavior of Alloy EP-823 as a function of heat treatment.

Highlights of Accomplishment

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Analysis Of Corrosion Of Steel By Lead Bismuth Eutectic, John Farley, Dale L. Perry

Transmutation Sciences Materials (TRP)

We examined stainless samples that were exposed to LBE in experiments conducted by the Russians, under contract to Los Alamos. We examined both corroded and uncorroded samples using the Scanning Electron Microscope (SEM), the Energy Dispersive X-Ray (EDAX) Spectroscopy, and the X-ray Photoelectron Spectrometer (XPS). We found that the surface of the corroded sample is covered by oxygen-containing compounds, presumably mostly iron oxide. In samples exposed for shorter times or lower temperatures, we found that some areas were covered by an oxide layer, and some areas was uncovered. We found that the level of Cr in the uncovered area is …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics: Quarterly Progress Report August 16,2001- November 15, 2001, 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 AAA 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 very limited density. The transport of oxygen and corrosion products, their interaction and variation of corrosion/precipitation along the flow are not well understood.

The first subtask of this project involves using a …

Classical Density Functional Theory Of Freezing In Simple Fluids: Numerically Induced False Solutions, M. Valera, F. J. Pinski, Duane D. Johnson

Duane D. Johnson

Density functional theory (DFT) has provided many insights into the freezing of simple fluids. Several analytical and numerical solution have shown that the DFT provides an accurate description of freezing of hard spheres and their mixtures. Compared to other techniques, numerical, grid-based algorithms for solving the DFT equations have more variational freedom and are capable of describing subtle behavior, as that seen in mixtures with multipeaked density profiles. However the grid-based approach is sensitive to the coarseness of the mesh employed. Here we summarize how the granularity of the mesh affects the freezing point within the DFT. For coarse meshes, …

Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

Capillary flow of a sinusoidally perturbed liquid column in an interior corner of infinite extent is solved using lubrication theory. Due primarily to the length scales selected to nondimensionalize the momentum equation, an analytic time scale governing the settling of the perturbation is determined. The time scale, which is shown to be independent of a steady base state flow, proves useful in rapidly predicting transients for surface settling in certain liquid-bearing tanks of spacecraft employing interior corners for fluids management purposes. The asymptotic analysis is extended to address flows along interior corners whose faces are slightly nonplanar. The generalized formulation …

Highly Plasma Etch-Resistant Photoresist Composition Containing A Photosensitive Polymeric Titania Precursor, Tony D. Flaim, Douglas J. Guerrero, Michelle R. Fowler, William Joseph James, Vladimir Petrovsky, Harlan U. Anderson

Chemistry Faculty Research & Creative Works

A composition is derived from an addition polymerizable organotitanium polymer which upon exposure to an oxygen plasma or baking in air, is converted to titanium dioxide (titania) or is converted to a mixed, titanium-containing metal oxide. The metal oxide formed in situ imparts etch- resistant action to a patterned photoresist layer. The composition may also be directly deposited and patterned into permanent metal oxide device features by a photolithographic process.

Odpady Pestycydowe Jako Paliwo Zastępcze W Piecach Obrotowych Do Wypalania Klinkieru Cementowego, Marian Mazur, Robert Oleniacz, Marek Bogacki, Stanisław Słupek

Robert Oleniacz

The clinker burning plant is ideally suited for processing a wide variety of hazardous waste materials. High temperatures existing in cement kilns (ca. 1350-1450 Centigrades in the burning zone) as well as long gas-residence time (ca. 6-10 s) provide potentially excellent conditions for destruction of toxic organic compounds. Non-volatile compounds are retained in the solid phase and built into the clinker. A lot of other (for example acid gases) can also be absorbed by alkaline solid phase. Old pesticide wastes present a big problem in Poland now. They can be use as waste-derived fuels in cement kilns, especially in the …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Aaa Task-4 Quarterly (June 1 – August 31, 2001) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The subject task entitled “Hydrogen-Induced Embrittlement of Candidate Target Materials for Applications in Spallation-Neutron-Target Systems” had commenced during the quarter ending on August 31, 2001. A research account has been established, contracts for both faculty and students have been prepared, and efforts are well underway to embark on the related research activities, as proposed.

As the title of this project implies, the primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate materials for applications in spallationneutron- target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). …

Microstructure And Electrochemical Properties Of The Melt_Spinning Zr_(0.9)Ti_(0.1) (Ni,Co,Mn,V)_(2.1) Alloy, Ming-Fen Wen, Yu-Chun Zhai, Lian Chen, Min Tong, Hua Zhen, Rong-Jun Ma

Journal of Electrochemistry

The microstructure and electrochemical properties of Zr 0.9 Ti 0.1 (Ni,Co,Mn,V) 2.1 alloys prepared by both the melt_spinning method and the conventional induction melting were investigated. XRD studies show that Zr 0.9 Ti 0.1 (Ni,Co,Mn,V) 2.1 alloys at as_cast,melt_spinning and annealing are all face center cubic structure with C15 laves phase,the higher the melt_spinning rate,the more the amorphous content.The electrochemical measurements show that melt_spinning alloys have better active behavior,low discharge capacity(<280 mAh/g); but after annealed,the alloys are activated completely with 30 cycles, the capacities about 340 mAh/g are higher than those of as_cast and melt_spinning alloys;the annealec alloys have a better cycle stability than that of as_cast alloy, and the higher the melt_spinning rate is, the more stable the alloy becomes; at 300 mAh/g current density,the capacity of annealed 40 m/s alloy is up to 85% of the maximum capacity after 800 cycles, the capacity decay rate is about 6.9%.

In Situ Ftir Reflection Spectroscopy Of Bioelectrode, Sa-Ying Dong, Guang-Yu Zhao, Yuzhu Gao, Guang-Zhang Chen, Ming-Xiang Lv

Journal of Electrochemistry

In situ FTIR reflection spectroscopy was used to study mediated enzyme electrode and immunoelectrode. We determined and analyzed IR characteristic spectra of GOD and glucose by the use of potential difference spectra and single beam subtractive spectra. At last, we explored the IR absorption characters of enzyme_immunoelectrode.

Current Oscillations In The System Of Carbon Steel/Phosphoric Acid/Platinum, Shao-Yuan Shi, Jin-Ping Wu, Jing Liu, An Lin

Journal of Electrochemistry

The periodic,aperiodic,chaotic and mixed_mode oscillations can occur in the process of the anodic electrodissolution of carbon steel in the solution of dilute phosphoric acid. More plentiful dynamic behaviors can be found in this system compared with the system of Fe/H 3PO 4/Pt.

A New Method For Impregnating Nafion Solution Into The Electrode Of Pemfc, Qian Tang, Ming Han, Bao-Lian Yi, Zhi-Yin Lin

Journal of Electrochemistry

We have developed a new method for impregnating Nafion solution into the catalyst layer of homemade hydrophobic electrode using capillary process. Those electrodes show better performance and higher utilization of catalyst (detected by CV and TEM) than traditional spray method in PEMFC. According to the results of SEM photograph and linear_analysis of sulfur and platinum for the electrode cross_section, we can conclude that the resin is uniform in the catalyst layer and has almost same depth as catalyst in the impregnated electrode. While in traditional method resin is not uniform in the catalyst layer and penetrates into the diffusion layer, …

The Coulostatic Method For Evaluating Corrosion In Reinforced Concrete, Yong Tao Zhao, Jian Hua Wu, Chang-Jiu Zhao

Journal of Electrochemistry

In the present paper, the application of the coulostatic method to the corrosion of steel in concrete was reviewed. By comparing with other electrochemical techniques, the results obtained in the previous work reveal that the coulostatic method is an interesting alternative to the usual procedures for estimation of corrosion rate, and is better than them in some respects. The main advantages are as follows. The signal to be used can be instantaneous and as small as desired, so the electrode is minimally perturted during the measuring process. In addition, it is as rapid and quantitative, and at least as reliable …