Physical Sciences and Mathematics Commons^™

A Study Of The Corrosion On Bronze, Hong-Fan Zhu, Hao Zhou

Journal of Electrochemistry

The bronze is the treasure in chinese metallic antique, which was typified by product in Shang-Zhou period (three thousands years ago). Because of corrosion, archaeological messages, such as inscription and pattern on the surface of bronze, would be damaged then the value of bronze antique decreased. The bronze disease is a common disease which forms powdery rust on the surface of bronze in atmospheric environment, the powdery rust emerge from under incrusted rust, then spreads, and eventually leads to bronze damaged. This paper investigates the bronze disease. According to the chemical and electrochemical tests in simulated occluded cell, the variation …

Influence Of Thiourea And Its Derivate On The Process Of Cathodic Electrodeposition Of Copper, Yun-Hui Dong, Ai-Hong Zou, Yun-Xia Zhao

Journal of Electrochemistry

The effects of thiourea and its derivate on the electrodeposition of copper from the dilute acid sulphate solutions have been studied by using potential sweep techniques at quasisteady state. Limiting current densities (I_d), exchange current densities (i₀) and α_n are obtained by data processing with the least square method. Thiourea has a depolarizing effect on the copper depositing at concentrations below 8 mg·L^-1, and a polarizing effect at higher concentration (>10 mg·L^-1), and it changes the mechanism of copper deposition reaction. Propenyltiourea and Phenylthiourea have a depolarizing effect on the …

Study On Synthesizing Of 2-Methylbutanoic Acid By Indirect Electrooxidation, Chong-Tao Zhao, Ze-Shan Zhu

Journal of Electrochemistry

The working conditions of synthesizing 2-methylbutanoic acid by oxidizing 2-methyl-1-butanol with tetrabutylammonium hydrosulfate (TBAS) or tetrabutylammonium perchlorate (TBAP) as phase transfer catalyst in sulfuric acid Cr(Ⅵ) oxidation medium was studied. The Cr(Ⅵ) oxidation medium could be electrolytic regenerated from Cr(Ⅲ), during above oxidation reaction. Under the optinum condition, the yield of 2-methylbutanoic acid is more than 95%.

Electrochemical Synthesis Of Fes Electrode And Its Behavior Measurement, Cong-Sheng Guan

Journal of Electrochemistry

The Potential for the electrochemical synthesis of FeS electrode has been obtained by cyclic voltammetry. FeS electrodes were synthesiaed by controlling Fe electrode at -1.0 V in LiCl-KCl-Li₂S and Li(FClI)-Li₂S melts and their behavior were measured also. The FeS electrode synthesized in molten Li(FClI)-Li₂S has the best charge and discharge properties.

Spectroellipsometric Studies On Electrochemistry And Its Application, Zong-Qing Huang, Sheng-Tao Zhang, Shang-Fen Xie, Chang-Guo Chen, Yu-Ru Yang, Wei Zhu

Journal of Electrochemistry

Ellipsometric measurements are often extremely sensitive to the presence of very thin surface layers,to changes in their thickness (or coverage), and to changes in surface topography at an atomic scale. These characteristics make the use of ellipsometry for electrochemical studies particularly attractive. The ellipsometric studies on electrochemistry and its applications carried out in the Electrochemical Laboratory of Chongqing University are reviewed briefly: 1)The studies on electrochemistry of classical ellipsometry. 2)The new function V_op suggested by the authors. 3)The applications of new approcaches with new function V_op suggested by the authors.

Studies On The Inclusion Complexes Of Rhein With Cds By Oscilloscope Polarography, Xiang-Jun Li, Jun Lian, Yong Zhang, Jing-Hao Pan

Journal of Electrochemistry

Inclusion action of rhein with CDs was studied by linear sweep oscilloscope polarography. The molar ratio of inclusion complexes of rhein with CDs are 1:1, the inclusion constants in different temperature have been determined and the thermodynamics parameter of some inclusion complexes have also been obtained. It indicates that in normal temperature, the inclusion procedure go on spontaneously, improving temperature is unfavorable to the formation of inclusion complexes.

Preparation And Ionic Conductivity Of Nanometer-Sized Li2+XGdXSi1+XO3 By The Sol-Gel Method, Ru-Fen Chen, Xiu-Qin Song, Hua-Ting Liu

Journal of Electrochemistry

Li_2+xGd_xSi_1-xO₃(x =0～0.15) samples have been prepared by the Sol-Gel method. The power samples were characterized by DTA-TG, XRD and TEM. Ionic conductivity of the sinter was determined by means of A-C impedance measurements. The experimental results showed that the range of solid-solution was 0 < x ≤ 0.09, while the conductivity of samples raised with increasing amount of Gd₂O₃ added, and average grain size of samples was 80 nm. In comparing with the samples by the conventional solid state reaction, the samples prepared by Sol-Gel method required lower temperature and presented higher ionic conductivity.

A Study Self-Passivation Of Passivie Film Of Stainless Steel In Vinylon Aldehyde Solution, Si-Fu Hu, Chuan-Bi Xu, Zhu-Qiu Cheng

Journal of Electrochemistry

Properties of self-passivation for the anodic passive film of 1Cr18Ni9Ti and the firsthand passive film of SUS 36 stainless steel in vinylon aldehyde solution(H₂SO₄(240 g/L)+Na₂SO₄(70 g/L)+HCHO(25 g/L)+[Fe³⁺](35.4 mg/L)+[Cl^-](240 mg/L) at 70 ℃ were studied by galvanostatic and potentiostatic polarization mesurements. The effects of compponents of vinylon aldehyde solution, i.e. Fe³⁺ and Cl^-, on the passivation behaviours of stainless steel have also been investigated. The experimental results showed there is a conversion zone of the active/passive state if the area ratio of active/passive state on these …

Effects Of The Surfactant And Ph On Linear Potential Scan Of Aqueous Na2S Solution, Qing-Feng Yi, Qi-Yuan Chen, Ping-Min Zhang

Journal of Electrochemistry

In presence of a cationic surfactant HTAB,linear potential scans for Na₂S at graphite anode in both saturated sodium tetra-borate solution and 1 mol·L^-1 NaOH solution, have been investigated. Results show that anodic current density increases and peak potentials shift to more negative with the increase of HTAB concentrations. The anodic current densities increased by addition of HTAB are larger in 1 mol·L^-1 NaOH than those in saturated sodium tetra-borate solution, resulting from different acting forces of HTAB with various charged electro-active species. Both oxidation and reduction peaks in cyclic voltammograms for Na₂S containing solution …

Almost Periodic Factorization Of Certain Block Triangular Matrix Functions, Ilya M. Spitkovsky, Darryl H. Yong

All HMC Faculty Publications and Research

Let

where , and . For rational such matrices are periodic, and their Wiener-Hopf factorization with respect to the real line always exists and can be constructed explicitly. For irrational , a certain modification (called an almost periodic factorization) can be considered instead. The case of invertible and commuting , was disposed of earlier-it was discovered that an almost periodic factorization of such matrices does not always exist, and a necessary and sufficient condition for its existence was found. This paper is devoted mostly to the situation when is not invertible but the commute pairwise (). The complete description is …

Divisible Tilings In The Hyperbolic Plane, Sean A. Broughton, Dawn M. Haney, Lori T. Mckeough, Brandy M. Smith

Mathematical Sciences Technical Reports (MSTR)

We consider triangle-quadrilateral pairs in the hyperbolic plane which "kaleidoscopically" tile the plane simultaneously. In this case the tiling by quadrilaterals is called a divisible tiling. All possible such divisible tilings are classified. There are a finite number of 1,2, and 3 parameter families as well as a finite number of exceptional cases.

Switching Properties Of Self-Assembled Ferroelectric Memory Cells, M. Alexe, Alexei Gruverman, C. Harnagea, N. D. Zakharov, A. Pignolet, D. Hesse, J. F. Scott

Alexei Gruverman Publications

In this letter, we report on the switching properties of an ordered system of Bi₄Ti₃O₁₂ ferroelectric memory cells of an average lateral size of 0.18 μm formed via a self-assembling process. The ferroelectricity of these cells has been measured microscopically and it has been demonstrated that an individual cell of 0.18 μm size is switching. Switching of single nanoelectrode cells was achieved via scanning force microscopy working in piezoresponse mode.

Distinguishing Between Cold Dark Matter And Modified Newtonian Dynamics: Predictions For The Microwave Background, Stacy S. Mcgaugh

Faculty Scholarship

Two hypothesized solutions for the mass discrepancy problem are cold dark matter and modified Newtonian dynamics. The virtues and vices of these very different hypotheses are largely disjointed, making the process of distinguishing between them very dependent on how we weigh disparate lines of evidence. One clear difference is the nature of the principal mass constituent of the universe (cold dark matter or baryons). This difference in the baryon fraction (fb, ≈ 0.1 vs. 1) should leave a distinctive signature in the spectrum of fluctuations in the cosmic microwave background. Here I discuss some of the signatures that should be …

A Patching Model For Surface Tension And The Tolman Length, T.V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of density functional theory (DFT), a patching model for the density profile of the liquid–vapor interface is developed. The patching is based on analytical expressions of the asymptote of the density profiles. Derived from the model the surface tension of planar liquid–vapor interface as well as the Tolman length can be computed from analytic expressions. Two prototype systems are considered; the Yukawa and the Lennard-Jones. As a result, the temperature dependence of the surface tension as well as the Tolman length are obtained. The results are compared with numerical DFT calculations.

Mathematical Modelling Of Extracellular Matrix Dynamics Using Discrete Cells: Fiber Orientation And Tissue Regeneration, J. C. Dallon, J. A. Sherratt, P. K. Maini

Faculty Publications

Matrix orientation plays a crucial role in determining the severity of scar tissue after dermal wounding. We present a model framework which allows us to examine the interaction of many of the factors involved in orientation and alignment. Within this framework, cells are considered as discrete objects, while the matrix is modeled as a continuum. Using numerical simulations, we investigate the effect on alignment of changing cell properties and of varying cell interactions with collagen and fibrin.

The Effect Of Abundance Variations On Estimates Of The Densities Of Broad-Line Region Clouds In Quasars, Stephanie A. Snedden, C. Martin Gaskell

C. Martin Gaskell Publications

There has been a long-standing discrepancy between the densities deduced from studies of the variability of quasar emission lines and those inferred from standard photoionization analyses. We have found that the higher metal abundances now believed to be present in most quasars lead to the higher densities being predicted by photoionization models. We explain why this is so.

The Galactic Center Isolated Nonthermal Filaments As Analogs Of Cometary Plasma Tails, Steven N. Shore, Ted La Rosa

Faculty Articles

We propose a model for the origin of the isolated nonthermal filaments observed at the Galactic center based on an analogy to cometary plasma tails. We invoke the interaction between a large-scale magnetized galactic wind and embedded molecular clouds. As the advected wind magnetic field encounters a dense molecular cloud, it is impeded and drapes around the cloud, ultimately forming a current sheet in the wake. This draped held is further stretched by the wind flow into a long, thin filament the aspect ratio of which is determined by the balance between the dynamical wind and amplified magnetic field pressures. …

Two New Topologically Ordered Glass Phases Of Smectics Confined In Anisotropic Random Media, Brad Jacobsen, Karl Saunders, Leo Radzihovsky, John Toner

Physics

Smectics in strained aerogel exhibit two new glassy phases. The strain both ensures the stability of these phases and determines their nature. One type of strain induces an “ XY Bragg glass,” while the other creates a novel, triaxially anisotropic “ m = 1 Bragg glass.” The latter exhibits anomalous elasticity, characterized by exponents that we calculate to high precision. We predict the phase diagram, and numerous other experimentally observable scaling laws, for the system.

Assignment Of The Infrared Spectra Of The Methanol Trimer, Gregory S. Tschumper, Jason M. Gonzales, Henry F. Schaefer

Chemistry Faculty Research & Creative Works

Second-order Möller-Plesset perturbation theory (MP2) and density functional theory (DFT) were employed to optimize two cyclic conformations of the methanol trimer, denoted "bowl" and "chair," as well as a third noncyclic, "open-chain" conformation. This is the first time all three methanol trimer conformations have been studied at the same level of theory. Harmonic vibrational frequencies confirm that all stationary points are minima on the intermolecular potential energy hypersurface. The chair is consistently predicted to be the most stable conformer. The bowl and open-chain conformers are only slightly less stable and lie within 3 kcal/mol. Results indicate that the bowl structure …

Two-Dimensional Nuclear Magnetic Resonance Correlation Spectroscopy At Zero Field, Ming-Yuan Liao, Gerard S. Harbison

Gerard S. Harbison Publications

Three methods for two-dimensional correlation nuclear magnetic resonance spectroscopy at zero field are discussed. All three involve coherence transfer via longitudinal polarization, double quantum coherence, or both in parallel. The double quantum pulse sequences exploit the spinor property of spin states. These sequences have been applied to connected Δm=1 transitions, as well as for the indirect detection of forbidden or nearly forbidden Δm.1 transitions.

Temporal Probabilistic Logic Programs, Alex Dekhtyar, Michael I. Dekhtyar, V. S. Subrahmanian

Computer Science and Software Engineering

There are many applications where the precise time at which an event will occur (or has occurred) is uncertain. Temporal probabilistic logic programs (TPLPs) allow a programmer to express knowledge about such events. In this paper, we develop a model theory, fixpoint theory, and proof theory for TPLPs, and show that the fixpoint theory may be used to enumerate consequences of a TPLP in a sound and complete manner. Likewise the proof theory provides a sound and complete inference system. Last, but not least, we provide complexity results for TPLPs, showing in particular, that reasonable classes of TPLPs have polynomial …

An Evaluation Of Land Use Changes And Their Associated Hydrologic Impacts In The Birch Creek Watershed, Halifax County, Virginia 1986-1998, Melissa Anne Lloyd

Theses & Honors Papers

This project is a study of the water quality and land us e changes that have occurred in the Birch Creek watershed in Halifax County, Virginia from 1987 to 1998. The purpose of t his project i s to identify water quality trends and potential linkages to land use changes during the time frame of the study. The information was obtained by analyzing data collected by the Virginia Department of Environmental Quality. The data had been gathered and archived, but not previously examined for trends or causal factors. Through the analysis, definite increasing and decreasing trends in the concentrations of …

1H Nmr Studies On The Cua Center Of Nitrous Oxide Reductase From Pseudomonas Stutzeri, Richard C. Holz, Marcela L. Alvarez, Walter G. Zumft, David M. Dooley

Chemistry Faculty Research and Publications

¹H NMR spectra of the Cu_A center of N₂OR from Pseudomonas stutzeri, and a mutant enzyme that contains only Cu_A, were recorded in both H₂O- and D₂O-buffered solution at pH 7.5. Several sharp, well-resolved hyperfine-shifted ¹H NMR signals were observed in the 60 to −10 ppm chemical shift range. Comparison of the native and mutant N₂OR spectra recorded in H₂O-buffered solutions indicated that several additional signals are present in the native protein spectrum. These signals are attributed to a dinuclear copper(II) center. At least …

The Methionyl Aminopeptidase From Escherichia Coli Can Function As An Iron(Ii) Enzyme, Ventris M. D'Souza, Richard C. Holz

Chemistry Faculty Research and Publications

The identity of the physiologically relevant metal ions for the methionyl aminopeptidase (MetAP) from Escherichia coli was investigated and is suggested to be Fe(II). The metal content of whole cells in the absence and presence of expression of the type I MetAP from E. coli was determined by inductively coupled plasma (ICP) emission analysis. The observed change in whole cell concentrations of cobalt, cadmium, copper, nickel, strontium, titanium, and vanadium upon expression of MetAP was negligible. On the other hand, significant increases in the cellular metal ion concentrations of chromium, zinc, manganese, and iron were observed with the increase in …

Online Track Processor For The Cdf Upgrade, C. Ciobanu, J. Gerstenslager, J. Hoftiezer, R. Hughes, M. Johnson, P. Koehn, C. Neu, C. Sanchez, B.L. Winer, J. Freeman, S. Holm, J.D. Lewis, T. Shaw, T. Wesson, Kenneth A. Bloom, D. Gerdes, J.W. Dawson, W.N. Haberichter

Kenneth Bloom Publications

A trigger track processor is being designed for the CDF upgrade. This processor identifies high momentum (P_T > 1.5 GeV/c) charged tracks in the new central outer tracking chamber for CDF 11. The track processor is called the extremely Fast Tracker (XFT). The XFT design is highly parallel to handle the input rate of 183 Gbits/sec and output rate of 44 Gbitslsec. The processor is pipelined and reports the results for a new event every 132 ns. The processor uses three stages, hit classification, segment finding, and segment linking. The pattern recognition algorithms for the three stages are implemented …

Electrodeposition Of Cerium-Based Coatings For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Xuan Lin, Eric L. Morris, Pu Yu, Srinivas Pravin Sitaram

Chemistry Faculty Research & Creative Works

A process for enhancing the corrosion resistance of an aluminum-containing component with a cerium based coating. An aluminum-containing cathode and an oxygen- evolving anode are immersed in an electrolyte comprising water, solvent, oxidizing agent and cerium ions. An electrical current is passed through the electrolyte by applying electrical current to deposit a cerium based coating onto the cathode. An electrolyte for use in depositing a cerium based coating. An electrodeposited cerium-based coating. An aluminum aircraft structural component having a cerium-based coating thereon.

Some Notions Of Complex Adaptive Systems And Their Relationship To Our World, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper assumes that the world we live in consists of many interwoven complex adaptive systems. In the literature such systems are characterized as comprising many moving parts and processes that interact significantly in a mostly non-linear manner. It is argued that the forces that act on such complex systems are not additive, and that their impact occurs along non-linear interactions within the system. In particular, many of these systems are adaptive in that they change their behavior (through their interactions) over time, so that if they are subjected to a similar force or event a second time they …

The Second Generation Integrated Collaborative Decision Making (Icdm) Model: A Three-Tier Approach To Agent-Based, Decision-Support Systems, Kym J. Pohl, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Ten years ago the CAD Research Center at California Polytechnic University in San Luis Obispo, California identified a standard framework for agent-based, decision support systems. Employing inter-process and inference engine technologies of the time, the CAD Research Center termed this ‘blueprint’ the Integrated Collaborative Decision-Making (ICDM) framework. Over the past twelve years ICDM has been successfully used as a foundation in several systems. These systems focus on a wide range of domains of application including architectural design and ship cargo stowage. Success of the ICDM framework in conjunction with the availability of newer technologies has prompted an evolutionary leap in …

Re-Engineering A Software Development Organization As A Complex Adaptive System, Steven J. Gollery, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper proposes that it is possible and desirable to restructure a software development organization as a complex adaptive system. Such a structure would increase the possibility that the organization would be able to survive and prosper in a rapidly-changing market place by shortening response time, increasing flexibility in the face of new and unexpected circumstances, and allowing the organization to learn quickly from its experiences.

The paper shows how a common information repository can be used to provide decision support to developers and managers, and discusses the relationship between decision support systems and complex adaptive systems.

Is Hyperconjugation Responsible For The "Gauche Effect" In 1-Fluoropropane And Other 2-Substituted-1-Fluoroethanes?, Paul R. Rablen, R. W. Hoffman, D. A. Hrovat, W. T. Borden

Chemistry & Biochemistry Faculty Works

The energies and geometries of a series of 2-substituted-1-fluoroethanes were computed at the MP2/6-311++G**(6D)//MP2/6-31+G* level of theory for both the maxima and minima of the rotation about the C-C bond. The results did not support the predictions of a hyperconjugative model, that both 1,2-difluoroethane and 1-chloro-2-fluoroethane would strongly prefer a gauche conformation, and that 1-fluoro-2-silylethane would strongly prefer an anti conformation. The existence of competing electrostatic interactions between the fluorine and the substituents at C-2 was indicated by the detailed geometries of the gauche conformers and by the calculated sensitivity of the gauche-anti energy differences to the presence of a …