Physical Sciences and Mathematics Commons^™

A Study For The Data Analysis Of Electrochemical Noise With Wavelet Analysis, Hong-Bo Ding, Bao-Yun Xia, Zhong-Xiao Pan, Chang-Jian Lin

Journal of Electrochemistry

In the process of electrochemical dynamics system,the phenomenon of the random fluctuations of electrochemical parameters(electrode potential,cell current,etc.)is called “Electrochemical Noise”(ECN).Wavelets analysis is one new data analysis technique which has undergone a breakthrough in the area of mathematics and singnal processing in recent years.In this paper,the technique of continuous wavelet transform has been employed to investigate electrochemical noise data,and the chaotic nature of corrosion process has been manifested.

Effect Of N-Ion Implantation On The Anodic Polarization Behavior Of Surgery Medical Materials In Artificial Body Fluid, Liang Guo, Cheng-Hao Liang, Hong-Yan Sui

Journal of Electrochemistry

Effect of N_ion implantation on the anodic polarization behavior of surgery medical materials, such as SUS316L stainless steel,Co_Cr alloy and Ti_6Al_4V alloy, has been investigated with electrochemical technology in artificial body fluid Hank's solution. With the tests of corrosion potential and anodic polarization curves, it can be seen that the anti_corrosion behavior is developed after implantion. XRD and AES profiles have shown that the metal nitride coated on the matrix after N_ion implantation, which isolates the matrix from environmental solution. The metal nitride film with high electrochemical capability plays an important role in inhibiting corrosion of the specimens.

Electrochemical Quartz Crystal Microbalance Study On The Promoted Electron Transfer Process At Gold Electrode, Xia-Qin Wu, Zhe-Su Wang, Xiao-Yun Meng, Zong-Rang Zhang

Journal of Electrochemistry

The adsorption behavior of amino acids, such as L_cysteine, histidine and arginine at gold_quartz crystal microbalance (Au_QCM) was investigated. The adsorption quantity of cysteine is more appreciable than others because of the stronger interaction between its thiol group and the gold electrode surface. The electron_transfer process of superoxide dismutase(SOD) in presence of cysteine at Au_QCM has also been studied using the electrochemical quartz crystal microbalance (EQCM) technique which reveals clearly the quasi_reversible electron_transfer process accompanied by the frequency shift cycle. The reversible adsorption and disorption processes are discussed.

Electrocrystallization Mechanism And Grain Sizes Of Ni-W-B Alloy Eletrodeposits, Fang-Zu Yang, Gang-Min Cao, Xiao Hu, Shu-Kai Xu, Shao-Min Zhou

Journal of Electrochemistry

The electrodeposition characteristics and grain sizes of Ni_W_B alloy have been studied by cyclic voltammetry, potentiostatic step and X_ray diffraction (XRD). The results showed that Ni_W_B alloy electrodeposit obtained from the solution containing ammonium citrate as a complexing agent was presented in the lower electrochemical activity compared with Ni_W alloy. Based upon the i～t curves of potentiostatic step, it was revealed that electrocrystallization of Ni_W_B alloy on glassy carbon followed the mechanism of instantaneous nucleation and three dimensional growth with diffusion controlled. The crystal nucleus number on the surface of electrode was raised by the increase of overpotential. According to …

Determination Of Kinetic Parameters Of Enzyme-Immunoelectrode For Sec Assay, Sa-Ying Dong, Xin-Miao Liu, Yuan-Zhi Wang, Guang-Zhang Chen, Ming-Xiang Lv, Bo-Yi Tian

Journal of Electrochemistry

Reaction mechanism of enzyme immunoelectrode is studied by potentiostatic. Rotating disk electrode is used to determine the controlling step of bioelectrode. Under different potentials and different modifying conditions, kinetic parameters of bioelectrodes were measured on the base of electrochemical impendance spectra. At the same time, these parameters are compared and discussed.

Study On Carbon From Pyrolyzing Phenol-Formaldehyde Resin For The Negative Electrode Of Li-Ion Secondary Battery, Zhi-Yuan Tang, Xin-Guo Zhuang, Yu-Mei Zhai, Jian-Gang Li, Jian-Jun Xue, Chun-Yan Liu

Journal of Electrochemistry

Li_ion secondary batteries negative electrodes were prepared by low temperature (<1 000 ℃) pyrolysis of commercial phenol_formaldhyde resin. A thermogravimetric analysis (TGA) and an X_ray diffraction (XRD) studies were peoformed for the pyrolytic carbonaceous materials. The results indicated that these samples are amorphous polyacenic structure materials. With increasing pyrolytic temperature, these materials become structurally order, and the first charge_discharge special capacities reduce. The specific capacities base on pyrolytic temperature, involving lithium storage nanometer cavities.

Preparation And Characteristics Of A Enzyme Electrode Based On Immobilization Of Tyrosinase In Electropolymerized Polypyrrole Film, Liu-Shui Yan, Qia Wei, Cheng-Yi Wang, Rong-Rong Shi, Xiao-Tong Ma

Journal of Electrochemistry

A sensitive and stable amperometric enzyme electrode was constructed, based on the immobilization of tyrosinase in potentiostatically electropolymerized polypyrrole film at a platinum electrode. The influence of pH and potential on immbilization was discussed. SEM micrographs and CV curves of films obtained before and after incorparation of tyrosinase molecular were analyzed and compared each other. The enzyme electrode responds linearly to p-cresol over a concentration range of 5×10 -8 ～1×10 -6 mol/L with an optimum pH of 6.6, It exhibited kinetic characteristics of the typical enzyme-catalyzed reaction with an apparent Michaelis constant of 2.2 ×10 -5 mol/L.

Template Synthesis And Uv-Vis Absorption Spectra Of The Nanowire Arrays Of Cadmium Chalcogenides

Journal of Electrochemistry

XU Shi_min, XUE Kuan_hong , KONG Jing_lin, SUN Dong_mei, FENG Yu_ying, LU Hai_yan (Dept. of Chem., Nanjing Normal Univ., Nanjing 210097, China) WANG Guang_hou (National Laboratory of Solid State Microstructures, Nanjing Univ., Nanjing 210093, China)The porous alumina membrane formed in the anodic oxidation of highly pure aluminum foil has attracted a great deal of attention in recent years [1] . It can be served as a desired template to prepare nanometer scale materials [2] due to its unique structure of discrete and cylindrical nanopores, paralleled one another, with the homogeneous size and distribution [3] . Chalcogenide semiconductors have promising prospect …

Study On The Effect Of Sodium Ion On Cycle Performance Of Lithium/Improved Graphite Lithium Ion Cell, Wen-Huang Huang, Yu-Shun Yan, Chun-Rong Wan, Chang-Yin Jiang

Journal of Electrochemistry

The different concentration of Na + was introduced into the non_aqueous eletrolyte system EC/DEC/LiClO 4 with 4A molecular sieve and lithiated 4A molecular sieve,by which the trace amount of water was removed.The concentrations of Na + and Li + were determined by atomic adsorption spectrometry. The cycle performance of lithium/improved graphite cells was then examined by charging and discharging under the constant electric current.The results demonstrated that the cycle performance of the cells was destroyed by the high concentration of Na + under the small electric current.With the increase of electric current,the cell became less sensitive to the concentration of …

Effect Of Carbopol And Polyvinylpyrrolidone On The Mechanical, Rheological, And Release Properties Of Bioadhesive Polyethylene Glycol Gels, Philadelphia University

Philadelphia University, Jordan

No abstract provided.

Naming And Sharing Resources Across Administrative Boundaries, Jonathan R. Howell

Dartmouth College Ph.D Dissertations

I tackle the problem of naming and sharing resources across administrative boundaries. Conventional systems manifest the hierarchy of typical administrative structure in the structure of their own mechanism. While natural for communication that follows hierarchical patterns, such systems interfere with naming and sharing that cross administrative boundaries, and therefore cause headaches for both users and administrators. I propose to organize resource naming and security, not around administrative domains, but around the sharing patterns of users.

The dissertation is organized into four main parts. First, I discuss the challenges and tradeoffs involved in naming resources and consider a variety of existing …

Measurement Of Inclusive(D(S)(±)) Photoproduction At Hera Zeus Collaboration, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The first measurement of inclusive D(s)(±) photoproduction at HERA has been performed with the ZEUS detector for photon-proton centre-of-mass energies 130 < W < 280GeV. The measured cross section for 3 < p (is perpendicular to)/(D(s)) < 12GeV and |η(D(s))| < 1.5 is σ(ep → D(s)X) = 3.79 ± 0.59(stat.) -0.46/+0.26 (syst.) ± 0.94(br.)nb, where the last error arises from the uncertainty in the D(s)(±) decay branching ratio. The measurements are compared with inclusive D*(±) photoproduction cross sections in the same kinematic region and with QCD calculations. The D(s)(±) cross sections lie above a fixed-order next-to-leading order calculation and agree better with a tree-level O(αα(s)/3) calculation that was tuned to describe the ZEUS D*(±) cross sections. The ratio of D(s)(±) to D*(±) cross sections is 0.41 ± 0.07 (stat.) -0.05/+0.03 (syst.) ± 0.10(br.). From this ratio, the strangeness-suppression factor in charm photoproduction, within the LUND string fragmentation model, has been calculated to be γ(s) = 0.27 ± 0.05 ± 0.07(br.). The cross-section ratio and γ(s) are in good agreement with those obtained in charm production in e+e- annihilation. (C) 2000 Elsevier Science B.V.

Measurement Of Azimuthal Asymmetries In Deep Inelastic Scattering, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time. (C) 2000 Elsevier Science B.V.

Growth And Fabrication With Single-Walled Carbon Nanotube Probe Microscopy Tips, Chin Li Cheung, Jason H. Hafner, Teri W. Odom, Kyoungha Kim, Charles M. Lieber

Barry Chin Li Cheung Publications

Single-walled carbon nanotube (SWNT) probe microscopy tips were grown by a surface growth chemical vapor deposition method. Tips consisting of individual SWNTs (1.5–4 nm in diameter) and SWNT bundles (4–12 nm in diameter) have been prepared by design through variations in the catalyst and growth conditions. In addition to high-resolution imaging, these tips have been used to fabricate SWNT nanostructures by spatially controlled deposition of specific length segments of the nanotube tips.

Determination Of The Wavelength Dependence On The Metal Catalyzed Degradation Of The Herbicide Atrazine, Timothy Bertram

Honors Theses

Since the advent of modern herbicide use in the early twentieth century, researchers have been plagued with the obvious problem of herbicide disposal. Most herbicides are specifically designed to resist natural degradation processes so that they can remain effective in the field for a substantial amount of time. In addition, they are also made water soluble so that they can be easily applied to crops. Finally, they are specifically produced to kill undesirable plant species in the quickest and often crudest fashions. Due to these specific properties herbicides pose a general threat to other organisms living in the same geographic …

Establishing The Inundation Distance And Overtopping Height Of Paleotsunami From The Late-Holocene Geologic Record At Open-Coastal Wetland Sites, Central Cascadia Margin, Robert B. Schlichting

Dissertations and Theses

Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone earthquakes in the central Cascadia margin. Cascadia tsunami deposits have been reported for many coseismic subsidence events in bay marsh settings where tidal-channel features focus tsunami energy. Variable magnitude (8.5±0.5 Mw), frequency (500±300 yr recurrence), and rupture geometry produce widely varying computer model outcomes for Cascadia tsunami inundation. The results presented in this thesis provide specific quantitative data regarding tsunami inundation at the open coast.

Anomalous sand sheets that have been characterized …

Femtosecond Luminescence Dynamics In A Nonlinear Optical Organic Dendrimer, O. Varnavski, A. Leanov, L. Liu, James M. Takacs, T. Goodson Iii

James Takacs Publications

The ultrafast intrinsic dynamics of an organic dendrimer in solution and in a thin film is reported using fluorescence upconversion spectroscopy. Femtosecond decay is detected at higher emission energies, while at lower energies a fluorescence rise time (∼3 ps) was observed that is dependent on the solvent’s polarity. A strong excitation energy dependence of the decay pattern was also observed. Different synthetic functional groups that comprise the macromolecular dendrimer structure were investigated. The mechanism, which describes the complex dynamics in the dendrimer system, was found to be associated with the excitation of the attached chromophore nitroaminostilbene. These results indicate the …

Focus: New Info From Slow Muons, Brandon R. Brown

Physics and Astronomy

No abstract available.

The Melting Temperature Of Proton-Disordered Hexagonal Ice: A Computer Simulation Of 4-Site Transferable Intermolecular Potential Model Of Water, G.T. Gao, Xiao Cheng Zeng, Hideki Tanaka

Xiao Cheng Zeng Publications

We report computer simulation results of free energies of proton-disordered hexagonal ice and liquid water at atmospheric pressure with the 4-site transferable intermolecular potential model of water. A new reference system is used to calculate the free energy of the ice phase. The melting point of proton-disordered hexagonal ice at atmospheric pressure is found to be T_m=238 (±7) K. This result is consistent with a previous estimation, 230K< T_mK, from molecular dynamic simulation of the surface melting of the proton-disordered hexagonal ice [G.-J. Kroes, Surf. Sci. 275, 365 (1992)].

Superspace Geometrical Realization Of The N-Extended Super Virasoro Algebra And Its Dual, Carina Curto, James Gates Jr., V. G. J. Rodgers

Department of Mathematics: Faculty Publications

Abstract We derive properties of N-extended GR super Virasoro algebras. These include adding central extensions, identification of all primary fields and the action of the adjoint representation on its dual. The final result suggest identification with the spectrum of fields in supergravity theories and superstring/M-theory constructed from NSR N-extended supersymmetric GR Virasoro algebras.

[The version deposited with arXiv (February 2000) is also attached (below) as an additional file.]

Extralimital Records Of The Mexican Free-Tailed Bat (Tadarida Brasilensis Mexicana) In The Central United States And Their Biological Significance, Hugh H. Genoways, Patricia W. Freeman, Cary Grell

School of Natural Resources: Faculty Publications

Two new records of Tadarida brasiliensis mexicana are reported from Nebraska. The literature records of this taxon from the central United States are summarized. In this region of North America, these bats occupy a “natal range” where the species carries on regular reproductive activities and the populations are relatively stable, including California, Arizona, New Mexico, Texas, and Oklahoma. To the north of the natal range of T. b. mexicana is a “pioneering zone” where, under favorable conditions, the species is capable of reproducing and conducting its normal activities. The pioneering zone of the Mexican free-tailed bat includes Barber and Comanche …

An Improved Limit On The Rate Of The Decay K^+ -> Pi^+ Mu^+ E^-, Duncan Brown, R. Appel

Physics - All Scholarship

The experiment E865 at BNL places an upper limit on the branching ratio for the decay K+ -> pi+ mu+ e- of 3.9x10^-11 (90% C.L.). Along with with other results this yields a combined upper limit on this branching ratio of 2.8x10^-11. A new upper limit on the branching ratio for pi0 -> mu+ e- of 3.8x10^-10 (90% C.L.) is also established. The experiment and analysis are described.

The Peculiar Type Ic Supernova 1997ef: Another Hypernova, Koichi Iwamoto, Takayoshi Nakamura, Ken’Ichi Nomoto, Paolo A. Mazzali, I. John Danziger, Peter Garnavich, Robert Kirshner, Saurabh Jha, David Balam, John Thorstensen

Dartmouth Scholarship

SN 1997ef has been recognized as a peculiar supernova from its light curve and spectral properties. The object was classified as a Type Ic supernova (SN Ic) because its spectra were dominated by broad absorption lines of oxygen and iron, lacking any clear signs of hydrogen or helium line features. The light curve is very different from that of previously known SNe Ic, showing a very broad peak and a slow tail. The strikingly broad line features in the spectra of SN 1997ef, which were also seen in the hypernova SN 1998bw, suggest the interesting possibility that SN 1997ef may …

Approximation Algorithms For The Minimum Bends Traveling Salesman Problem, Cliff Stein, David P. Wagner

Computer Science Technical Reports

The problem of traversing a set of points in the order that minimizes the total distance traveled (traveling salesman problem) is one of the most famous and well-studied problems in combinatorial optimization. It has many applications, and has been a testbed for many of the must useful ideas in algorithm design and analysis. The usual metric, minimizing the total distance traveled, is an important one, but many other metrics are of interest. In this paper, we introduce the metric of minimizing the number of turns in the tour, given that the input points are in the Euclidean plane. To our …

Renormalization Scale Invariant Pqcd Predictions For R(E+ E-) And The Bjorken Sum Rule At Next-To-Leading Order, Michael Binger, Chueng-Ryong Ji, David G. Robertson

Physics Faculty Scholarship

We discuss the application of the physical QCD effective charge αV, defined via the heavy-quark potential, in perturbative calculations at next-to-leading order. When coupled with the Brodsky-Lepage-Mackenzie prescription for fixing the renormalization scales, the resulting series are automatically and naturally scale and scheme independent, and represent unambiguous predictions of perturbative QCD. We consider in detail such commensurate scale relations for the e+e− annihilation ratio Re+e− and the Bjorken sum rule. In both cases the improved predictions are in excellent agreement with experiment.

Shifting Distributional Patterns Of Mammals In Nebraska, Russell A. Benedict, Hugh H. Genoways, Patricia W. Freeman

School of Natural Resources: Faculty Publications

New distributional records are presented for 20 species of mammals in Nebraska. The majority of these records appear to represent changes in geographic distribution rather than just better sampling in poorly known areas. One group of mammals, including the opossum, northern myotis, evening bat, red bat, woodchuck, white-footed mouse, and gray fox, is expanding westward, probably in response to increasing woodlands along river systems. Another group, including the meadow vole, masked shrew, and least weasel, is expanding southward, possibly in response to new prey species and changing microclimates. The eastern woodrat appears to be expanding northward in eastern Nebraska. The …

Shifts In Mid- To Late-Holocene Anion Composition In Elk Lake (Grant County, Minnesota): Comparison Of Diatom And Ostracode Inferences, Jasmine E. Saros, Sherilyn C. Fritz, Alison J. Smith

Department of Earth and Atmospheric Sciences: Faculty Publications

The fossil diatom record from Elk Lake (Grant County, Minnesota) was used to reconstruct salinity and brine type between 2640 and 4645 ¹⁴C yr BP. This lake was selected for a brine-type reconstruction because a previous study using fossil-ostracode assemblages indicated a shift in anion composition during the mid-Holocene (Smith et al., 1997). Salinity was reconstructed using a transfer function developed for the Northern Great Plains (NGP) of North America; the reconstruction revealed that salinity was higher (1.5–6.2 g l⁻¹) between ~4000 and 4645 14C yr BP and dropped to 0.35–1.2 g l−1 after 4000 14C yr …

Low Temperature Anomaly In Mesoscopic Kondo Wires, P. Mohanty, Richard A. Webb

Faculty Publications

We report the observation of an anomalous magnetoresistance in extremely dilute quasi-one-dimensional AuFe wires at low temperatures, along with a hysteretic background at low fields. The Kondo resistivity does not show the unitarity limit down to the lowest temperature, implying uncompensated spin states. We suggest that the anomalous magnetoresistance may be understood as the interference correction from the accumulation of geometric phase in the conduction electron wave function around the localized impurity spin.

Performance Of Bootstrap Confidence Intervals For L-Moments And Ratios Of L-Moments., Suzanne Glass

Electronic Theses and Dissertations

L-moments are defined as linear combinations of expected values of order statistics of a variable.(Hosking 1990) L-moments are estimated from samples using functions of weighted means of order statistics. The advantages of L-moments over classical moments are: able to characterize a wider range of distributions; L-moments are more robust to the presence of outliers in the data when estimated from a sample; and L-moments are less subject to bias in estimation and approximate their asymptotic normal distribution more closely.

Hosking (1990) obtained an asymptotic result specifying the sample L-moments have a multivariate normal distribution as n approaches infinity. The standard …

Sulfite: Cytochrome C Oxidoreductase From Thiobacillus Novellus, Ulrike Kappler, Brian Bennett, Jörg Rethmeier, Günter Schwarz, Rainer Deutzmann, Alistair G. Mcewan, Christiane Dahl

Physics Faculty Research and Publications

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by sulfite: cytochrome c oxidoreductase (EC1.8.2.1). Here we show that the enzyme from Thiobacillus novellus is a periplasmically located αβ heterodimer, consisting of a 40.6-kDa subunit containing a molybdenum cofactor and an 8.8-kDa mono-heme cytochrome c ₅₅₂ subunit (midpoint redox potential, E _m8.0 = +280 mV). The organic component of the molybdenum cofactor was identified as molybdopterin contained in a 1:1 ratio to the Mo content of the enzyme. Electron …