Physical Sciences and Mathematics Commons^™

53. Takeo Saegusa, Otto Vogl

Otto Vogl

No abstract provided.

A Magnetic, Neutron-Diffraction, And Mössbauer Spectral Study Of The Ce₂Fe₁₇₋ₓsiₓ Solid Solutions, D. P. Middleton, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean, K. H. J. Buschow

Chemistry Faculty Research & Creative Works

The magnetic properties of a series of Ce₂Fe_17-xSi_x solid solutions with x equal to 0.0, 0.23, 0.4, 0.6, 0.8, 1.02, 1.98, and 3.20 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. An x-ray-diffraction study indicates that the compounds adopt the rhombohedral Th₂Zn ₁₇-type structure. The substitution of silicon for iron in Ce ₂Fe₁₇ leads to a contraction of the a axis by 0.2%, an expansion of the c axis by 0.2%, and a consequent reduction of the unit-cell volume by about 0.2% per substituted silicon. Magnetization studies …

Synthesis And Characterization Of Silicon Dioxide Thin Films By Plasma Enhances Chemical Vapor Deposition From Diethylsilane And Nitrous Oxide, Lan Chen

Theses

This study is focused on the synthesis and characterization of silicon dioxide thin films deposited on silicon wafers by plasma enhanced chemical vapor deposition(PECVD), using diethylsilane (DES) as a precursor and nitrous oxide (N₂O) as the oxidant. The process parameters, such as temperature, pressure and reactant gas composition have been systematically varied and their effects on the film growth rate and properties were investigated. The growth rate was found to be inversely proportional to the temperature in the examined range of 100-300°C. It increased with increasing N₂O/DES flow rate ratio as the total flow rate increased …

Factors Effecting Calcification Of Bioprosthetic Heart Valves, Sumei Yu

Theses

Calcification is the most frequent cause of clinical dysfunction of glutaraldehyde treated bioprosthetic heart valves. In this study, we compared calcification of bioprostheses of the No-ReactTM and the conventional glutaraldehyde treated pericardium by both in-vivo and in-vitro methods, and to further delineate the role of the host's inflammatory response in implant degeneration.

In the in-vitro study, the two types of pericardial samples were placed in individual polystyrene tubes containing physiological concentrations of calcium and phosphate and incubated for 21 days at 37°C. In the in-vivo study, the two types of pericardial samples were implanted subcutaneously in rats and subsequently retrieved …

Studies Of The Role Of Interfacial Molecular Structure To Adhesive Interaction, Cynthia Kraft, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Electrochemical And Infrared Spectroscopic Study Of Electrodes Modified By Alkoxyalkanethiols, Jimin Huang, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Understanding Proton Emission In Central Heavy-Ion Collisions, D. O. Handzy, W. Bauer, F. C. Daffin, S. J. Gaff, C. K. Gelbke, T. Glasmacher, E. Gualtieri, S. Hannuschke, M. J. Huang, G. J. Kunde, R. Lacey, T. Li, M. A. Lisa, W. J. Llope, W. G. Lynch, L. Martin, C. P. Montoya, R. Pak, Graham F. Peaslee, S. Pratt, C. Schwarz, N. Stone, M. B. Tsang, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello

Faculty Publications

Two-proton correlation functions for central collisions of 36Ar+45Sc at E/A=80, 120, and 160 MeV are compared to calculations with the Boltzmann-Uehling-Uhlenbeck (BUU) transport model. Agreement is found at E/A=80MeV, but the model predicts too large correlations at E/A=120 and 160 MeV. The discrepancy may be due to delayed emission of protons from particle-unstable states not modeled in BUU.

Tunable Picosecond Infrared Laser System Based On Parametric Amplification In Ktp With A Ti:Sapphire Amplifier, D. E. Gragson, D. S. Alavi, G. L. Richmond

Chemistry and Biochemistry

A picosecond laser system that will generate high-power tunable IR pulses with bandwidths suitable for spectroscopic applications is discussed. The system is based on white-light continuum generation in ethylene glycol and optical parametric amplification in potassium titanyl phosphate. The nonlinear-optical processes are driven by a regeneratively amplified Ti:sapphire laser that produces 1.7-ps pulses at a repetition rate of 1 kHz. Energies as high as 40 and 12 µJ have been achieved over the signal (1.02–1.16-µm) and idler (2.6–3.7-µm) tuning ranges, respectively. The IR beam temporal and spatial characteristics are also presented.

Reply To ‘‘Comment On ‘Brillouin-Scattering Study Of The Elastic Constants Of Phenothiazine Through The Phase Transition’ ’’, J. Sartwell, Craig J. Eckhardt

Craig J. Eckhardt Publications

Disagreement in the ordering of relative magnitudes of the elastic constants of phenothiazine with those of Ecolivet et al. is resolved. Dubious methodologies and assumptions employed by Ecolivet et al. in their measurements, approximations, and arguments [C. Ecolivet et al., Phys. Rev. B 44, 4185 (1991)] are noted. Samples employed by these investigators in both their ultrasonic and Brillouin measurements are shown to exhibit properties consistent with impure samples and inconsistent with those of Sartwell and Eckhardt.

54. Burkart Philipp, Otto Vogl, Ch. Wandrey

Otto Vogl

No abstract provided.

Structure Factors Of Binary Fluids In A Dilute Gel, J.C. Lee

Faculty Publications

The statio and dynamic structure factors of binary fluids in a dilute gel are computed using a two-dimensional kinetic Ising model. The wetting effect of the gel strands is modeled with ''gel atoms'' which are distributed randomly among the spins and impose a field on their neighboring spins, all in the same direction. The result for the static structure factor shows the presence of adsorption clusters which mask the gel atoms. The result for the dynamic Structure factor shows an extremely slow relaxation-at late times which cannot be fitted in the form of the activated dynamic scaling known for random-field …

Three-Phase Intersection Points In Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Some phospholipid/dihydrocholesterol Langmuir monolayers form coexisting liquid phases. Gas domains form at the interface between the phospholipid-rich and dihydrocholesterol-rich liquid phases when these monolayers undergo expansion to low surface pressure. Analysis of the domain shapes thus formed yields the relative line tensions of the gas/phospholipid, gas/dihydrocholesterol, and phospholipid/dihydrocholesterol phase interfaces.

55. Hermann Janeschitz-Kriegl, Otto Vogl, Anton Schausberger

Otto Vogl

No abstract provided.

Anisotropic Anharmonicity Of Lattice And Molecular Vibrations Of 1,2,4,5 Tetrabromobenzene Determined By Piezomodulated Raman Spectroscopy, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Strain-induced coupling constants for the anharmonicity of Raman-active lattice and certain molecular modes of vibration in 1,2,4,5-tetrabromobenzene (TBB) crystals have been determined using piezomodulated Raman spectroscopy. These constants, which are directly related to the first anharmonic term in the potential energy expansion for lattice dynamical calculations, are a quantitative measurement of the modal anharmonicities in the TBB molecular crystal. Application of uniaxial stress in the experiments permits the anisotropy of the anharmonicity to be determined as well as its magnitude. The TBB lattice modes are significantly coupled by the induced strains and the effects of coupling were observed to be …

Vr Projects, P.D. Quick

SWITCH

A description of three three projects having to do with virtual reality. The first is the Nanomanipulator, developed at the University of North Carolina Chapel Hill Department of Computer Science in conjunction with the UCLA Department of Chemistry in 1991. It is a machine that allows the user to interact with microscopic particles previously only visible in 2D from an electron microscope. The second project, The Augmented Reality Project, also developed at the Chapel Hill Department of Computer Science. This device used ultrasound images to be placed over a body allowing the user to see inside of it. The final …

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman

Publications (WR)

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from December 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradient of water quality conditions that existed in Las Vegas Bay (LVB). Disodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at all stations for most of the test dates. Chl a response with EDTA …

Detection Of Alzheimer's Disease And Other Diseases Using An Improved Photoaffinity Labeling Method, Boyd E. Haley

Chemistry Faculty Patents

An improved method for diagnosing a disease comprising detecting a disease-specific biochemical marker macromolecule within a sample of extracted cerebral spinal fluid or serum is disclosed. In particular, a radioactively labeled photoaffinity probe is used to diagnose a disease. For instance, Alzheimer's disease can be diagnosed by detecting a disease-specific protein having a molecular weight of about 42,000 daltons, i.e., glutamine synthetase. Also included is a method for detecting other disease states, such as cancer, by detecting the presence or absence of specific nucleotide binding proteins.

Effect Of Symmetric Alternating Current On Cathode Surface Before Iron Deposition, Xintan Hu

Journal of Electrochemistry

The composition and thickness of active film formed on the surface of cathodemade of low carbon steel after treated by symmetric alternating current(SAC)in ferris chloride bathis studied,and the interfacial morphology of the iron deposit and the substrate is also examined.Theresults show that the active film,which a thickness of 20～25nm can be obtained under SAC densityof about 7A dm￣(-2) ,so that the adherent iron deposit can be achieved on the active film. The effect ofSAC on cathode surface is discussed in detail.

Progress In R&D Of Lithium Rechargeable Batteries In China, Jiqiang Wang

Journal of Electrochemistry

No abstract provided.

The Determination Of The Reaction Rate Constant Of As(Ⅲ)Scavenging Etchant, Jin Luo, Lianyong Su, Jintian Wu, Zhonghua Lin, Zhaowu Tian

Journal of Electrochemistry

The mechanisms of the arsenite acid scavenging bromine and[Fe(Phen_3)]￣(3+)reaction were studied by the electrochemical methods. The arsenite acid scavenging bromine and[Fe(Phen_3)]￣(3+) reaction rate constants in sulfuric acid in the range of 23℃ to 69℃ and in the range of19℃ to 69℃ were determined by measuring the steady state limiting current,respectively.Theactivation energy of the arsenite acid scavenging bromine reaction in sulfuric acid is 33 kJ·mol￣(-1).

A Relativistic Density-Functional Investigation Of Vibrational Frequencies Of Cn￣- On Cu And Ag Electrodes, Mengsheng Liao, Xin Lv, Qianer Zhang

Journal of Electrochemistry

Abstract Potential Dependence,Vibrational Frequency,copper-electrode,Silver-electrode,Relativistic density-functional calculationAcknowledgements This work was supported by the National Natural Science Foundationof China and ChinaPostdoctoral Science Foundation.

The Oxidation Of Hydrogen Absotbing Alloys And Its Inhibition, Suqin Wang, Baojia Xia, Geping Yin, Pengfei Shi

Journal of Electrochemistry

This paper introduces the method to judge:1)the possibility of oxidation of themetal hydride electrode in an anode process by cyclic voltammetric curves,2)the oxidation pattern ofmetal hydride electrode in oxygen atmosphere in various charged states,and 3)the inhibition ofoxidation of hydrogen absorbing alloys by certain surface treatment.

Studies On Advanced Experimental Methods And Instruments In Electrochemistry, Zhonghua Lin, Jin Luo, Zhongqun Tian, Shigong Sun, Changjian Lin, Bingwei Mao, Yong Yang, Huashui Lin

Journal of Electrochemistry

The following recent advances in the experimental methods and home-madeinstruments in Electrochemistry by electrochemistry group in Xiamen University are briefly surveyed.

Self-Assembled Monolayers:Preparation,Properties And Application, Xiandui Dong, Juntao Lu, Chuansin Cha

Journal of Electrochemistry

Self-assembling technique is a versatile approach to the preparation of monolayersof well-defined composition,structure,thickness and physicochemical properties.Different aspects,such as wettability,adhesion,corrosion,tribology,electrontransfer,protein adsorption,molecularrecognition,and applications of SAMs are widely studied.The developments in the last decade arereviewed,with special attention to the electrochemical studies related to electrodes modified with thiol-derivative-based SAMs

Problems On The Study Of Anodic Films On Pb In Sulfuric Acid Solution(Ⅰ), Wenbin Cai, Houtian Liu, Weifang Zhou

Journal of Electrochemistry

The identification of the phase composition of the anodic film on Pb formed inH_2SO_4 solution in PbO potential region has long been argued,together with the explanation of thecathodic peak at about -0.9V(Hg/Hg_2SO_4)in the linear sweep voltammogram for a Pb-H_2SO_4system. In this article, a review of our recent investigations was presented on the above problems.

Electrodeposition Of Cobalt And Rare Earth-Cobalt In Urea-Nabr-Kbr Melt, Qiqin Yang, Kairong Qiu, Derong Zhu, Lichang Sa

Journal of Electrochemistry

No abstract provided.

The Influnce Of Conjugated Π Bond In Promoter Molecule On The Direct Electrochemical Reaction Of Cytochrome C, Xiaogang Qu, Tianhong Lu, Shaojun Dong

Journal of Electrochemistry

The promoter effect of thiophene with only one-functional group on the directelectrochemical reaction of cytochrome c was compared with that of tetrahydrothiophene in this report.It was found that thiophene is a good promoter.But tetrahydrothiophene could not facilitate the directelectrochemistry of cytochrome c although this compound is very similar to thiophene in str uctureexcept for conjugated π bond.This demonstrated that the conjugated π bond in thiophene plays animportant role for the acceleration of the direct electrochemistry of cytochrome c.

Studies Of Cl￣- On The Electrochemical Oscillation Behaviour Of Electrodeposited Silver Indium Selenide Thin Films By Using Dynamic Impedance And The Condensance Method, Shaoai Xie

Journal of Electrochemistry

The electrochemical oscillation behaviour of hydrogen peroxide cathodic reductionprocess on the electrodeposited silver indium selenide electrode has been studied by using in-situdynamic impedance and the condensance measurement technique in different supporting electrolytessolutions.The surface composition of AglnSe_2 electrodes(before and after oscillating)were also givenby AES. According to the experimental results,the influence of Cl￣- on the mechanism of thiselectrochemical oscillaton process has been discussed in detail.

The Photoelectrochemical Studies Of Passive Films On Rebar Electrodes In Simulated Cement Pore Solution, Wei Chu, Yuanxiang Shi, Baoming Wei

Journal of Electrochemistry

The electronic properties of the passive film on REBAR electrodes in simulatedcement pore solution(pH=9.0～13.8)have been investigated using in-situ photoelectrochemicalmethods.The results show that the passive film is composed of mixed oxides of ferrum ,and it is anamorphous,n-type semiconductive film. Variations of pH values,ions in the solution and film-formation potentials can affect the composition of the films. There are two main stages in the growthof the film,with two rate functions characterized by linear relation between the film thickness and thelogarithm of time.The addition of inhibitor NaNO_2 changes the composition,structure and growthkinetics of the film,and therefore improves the resistance of pitting corrosion induced …

Properties Of Zr-Based Laves Phase Hydrogen Storage Electrode, Xueping Gao, Huabin Yang, Deying Song, Yunshi Zhang, Zuoxiang Zhou, Wei Zhang, Panwen Shen

Journal of Electrochemistry

After treated by HF solution,the surface of Zr(V_(0.2)Mn_(0.2)Ni_(0.54)Mo_(0.06))_(2.4) alloywas transformed from Zr-rich and Mn-rich layer to Ni-rich layer.In this way,the nickel on thesurface could be believed to be the Raney-type nickel, which could obviously shorten the activationcycles,improve electrocatalytic activity and hydrogen adsorption ability.In this paper,the reactionmechanism on the alloy surface(i.e. the mechanism of nickel-catalysis,hydrogen-adsorption andhydrogen-transference)had been investigated.And the impedance spectra were fitted to an equivalentcircuit using a non-linear,least-squares(NLLS)fitting program.