Physical Sciences and Mathematics Commons^™

Direct Electrochemical Reaction Of Cytochrome C At The Poly (Ethylene Oxide) Film Modified Gold Electrodes, Xiaogang Qu, Gongquan Sun

Journal of Electrochemistry

In this paper, the direct electrochemical reaction of cytochrome c was sudied at the poly (ethylene oxide) film modified gold electrodes. It was found the PEO is a good promoter for the electrochemical reaction of cytochrome c, and the reversibility of reaction of cytochrome c was found to depend on the molecular weight of PEO and the morphology of the PEO films.

Modification Of Carbon Anode Materials Of Lithium Ion Secondary Battery, Yuping Wan Chunrong Wu, Changyin Jiang, Jiangiun Li

Journal of Electrochemistry

In this paper, the latest research work on modification of carbon anode materials of lithium ion secondary battery is reviewed. Modification methods include: incorporation of nonmetal elements such as boron, silicon, nitrogen, phosphorus and sulfur, metal elements such as potassium, aluminum, gallium and transitional metal elements such as vanadium, nickel, cobalt, copper and iron and surface treatment such as oxidation and formation of surface layer. Since these methods can affect the carbon materials' electronics state, crystal structure and surface structure, the electrochemical properties of the carbon materials could probably be improved. Besides, mechanisms for lithium storage in carbonaceous materials are …

External Transducing Measurement Of The Internal Pressure In Sealed Battery By Resistance Strain Gauge, Hanxi Yang, Ronghui Hu, Xinping Ai, Congzhi Yang, Shengxian Li

Journal of Electrochemistry

A novel method to monitor dynamically the internal pressure of sealed battery with no damage of the battery by using of resistance strain measurement technique is presented. This technique employs the resistence strain gauges in touch of the battery case and to detect the minimal change in the battery deformation due to the increasing internal pressure, electrode expantion or intrenal temperature rise. Application of the technique for the study of the effects of the battery processing factors on the battery performance is described taking Ni MH battery as example.

Lithiun Insertion In Carbon Nanotubes, Guotao Wu, Chunsheng Wang, Zhongfu Qi, Wenzhu Li

Journal of Electrochemistry

Carbon nanotubes were produced by chemical vapour deposition(CVD) of acetylene under hydrogen gas.The reversible specific capacity of carbon nanotubes is up to 700 mAh/g, much higher than the theoretical specific capacity of graphite(372 mAh/g).After twenty charge/discharge cycles,the discharge capacity of carbon nanotube anode still maintains 65.3% of its original discharge capacity . Besides, the charge/discharge efficiency of carbon nanotube in the first charge/discharge cycle was found to improve from 42.6% up to 55.9% by coating carbon nanotubes with copper.

Electrooxidation Of Benzene To Benzoquinone In A Packed Bed Reactor, Xinsheng Zhang, Ping Ding, Yingchun Dai, Weikang Yuan

Journal of Electrochemistry

A packed electrode reactor was used to oxidize to benzoquinone. Anode bed of the reactor has a size of 10～30 mm×450 mm×50 mm(thickness×length×width),and was packed porous lead alloy. A dispersion of benzene in 1 mol/L aqueous sulfuric acid was passed through the reactor. Current efficiency for benzoquinone generation is 62.9% at optimal operating condition: velocity of electrolyte flow, 0.19 ms -1 ;current, 10 A; thickness of anode bed, 10 mm, and percentage of benzene, 24%.

Study Of Electrocrystallized N(N≥40) Multilayers In Boric Acid Solution, Renhe Yin, Wenguang Shi, Weimin Cao

Journal of Electrochemistry

Co(0.5 nm～2.2 nm)/Pt(2.0 nm)] n(n>40) multilayers were prepared by electrocrystallization on copper and glass carbon with a dual cell technique under potential control.The periodical modulated structure of the multilayers was demonstrated by the low angle X ray diffraction. Potential shift negative to the deposition potential of the Co layer and positive to the deposition potential of the Pt layer decreased the value of the full width at half maximum(FWHM) of first Bragg Peak.CoPt 3 alloy was found as the interface of the multilayers by the middle angle X ray diffraction.The hysteresis loops show that the easy magnetization of these …

Electrochemical Determination Of Trace Amouns Of Gold(Ⅲ)By Cathodic Sptripping Voltammetry Using A Carborn Paste Electroele Modified With Bacteria, Rongzong Hu, Hao Xu, Jinkun Fu, Wenyun Hu, Yanzhen Chen

Journal of Electrochemistry

An electrochemically pretreated carbon paste electrode modified with bacteria has been studied and used for determination of trace amounts of gold(Ⅲ). A detection limit of 1 ng/mL was obtained by applying cathodic stripping valtammetry. There is a linear relationship between the concentration and peak height in the range of 10～100 μg/mL. The ralative standard deviation of the response to 84.7 μg/mL Au(Ⅲ) is 3.43%.

Studies On The Electrode Kinetics Of Electrooxidation Of Mn 2+, Wanli Hu, Tong Su, Wei Guo, Ding Zhou

Journal of Electrochemistry

The mechanism of electrooxidation of MnSO 4 on Pb Sb As alloy anode was investigated by using rotating disc electrode technique. The results shown that the conditional standard potential of Mn(Ⅲ)/Mn(Ⅱ)in 40% H 2SO 4 is 0.886 4 V.The rate controlling step of electrode process is mixed controlled by charge transfer and diffusion.

Studies On The Preparation Of Nanophase Electrode Materials And Its Electrochemical Properties(Ⅲ)—Performance Of Nm Γ Mno 2 Obtained By Microemulsion Method, Liu Ling, Xia Xi

Journal of Electrochemistry

A nanophase MnO 2 was synthesized using w/o microemulsion as reation media, The most favorable experiment conditions for the preparation of nm MnO 2 were researched. XRD,TEM,AC impedance, cyclic voltammetry etc. examinations were used to characterize the sample comparison with the classical MnO 2 (I.C.No.1EMD,electrolytic manganese dioxide). Sample shows that the crystal styucture of the synthesized samples are mainly γ MnO 2, with average particle size in the nanometer as shown by TEM. It was found that the discharge capacity of nm MnO 2 obtained is significantly higher than that of the I.C.No.1 EMD.

Study Of Proton Exchange Membrane Fuel Cells(Pemfc), Shanhai Ge, Baolian Yi, Hongfen Xu, Ming Han, Zhigang Shao

Journal of Electrochemistry

The electrode kinetic parameters for proton exchange membrane fuel cells(PEMFC) were investigated by measuring the relations of cell potential and current density. An experimental stack of PEMFC which can be operated at E cell =0.7V, I =0.55A/cm 2 steadily is presented, and the effects of electrode structure and operation conditions such as temperature, pressure, humidification, flow rate on the performance of PEMFC are discussed.

Influence Of Electrolytes To The Interfacial Electroc Characteristics Of The Porous Membrane Of Anodized Aluminum, Yafe Kuang, Ling Wang, Meiyuan Wang

Journal of Electrochemistry

The influence of electrolytic composition on the interfacial electric Characteristic of the porous membrane membrance of anodized aluminum was investigated with a electrodialytic method. Results indicated that, when the porous membrane was pretreated with F -, PO 3- 4,SiO 2- 3 and tannic acid, the isoelectric point in 0.01 mol/L KCI, were shifted from normal 9.20 to 3.40, 4.30, 3.30 and 4.50, respectively, and responsive characteristics of ζ potential to pH was changed. Furthermore, after pretreatment of porous membrance with fuchsine basic and fuchsine acid solution,there was no isoelectric point at 2.0

Detection Of Intergalactic Red-Giant-Branch Stars In The Virgo Cluster, Henry C. Ferguson, Ted Von Hippel, Nial R. Tanvir

Publications

It has been suspected for nearly 50 years that clusters of galaxies contain a population of intergalactic stars, ripped from galaxies during cluster formation or when the galaxies’ orbits take them through the cluster center. Support for the existence of such a population of free-floating stars comes from measurements of the diffuse light in clusters and from recent detections of planetary nebulae with positions and/or velocities far removed from any observed cluster galaxy. 10 , 11 But estimates for the mass of the diffuse population and its distribution relative to the galaxies are still highly uncertain. Here we report the …

Formation And Effect Of Tribo Cell For Fe Cr Alloy, Dongbai Sun, Tao Li, Hongying Yu, Deji Yang

Journal of Electrochemistry

The micro galvanic corrosion of 1Cr18 alloy and its effects on the triboelectrochemical behavior were investigated and analyzed in this article. It is shown that the micro galvanic corroson is due to the electrochemical inhomogenity on the surface of the alloy during the friction process. Like galvanic corrosion,the micro galvanic corrosion behaviors are greatly affected by the area ratio of unrubbed to rubbed surface.The load effects on electrochemical behavior of 1Cr18 alloy are also attributed to existence of electrochemical inhomogenity on the surface of materal.

Ac Impedance Study Of The La 0.8 Sr 0.2 Mno 3/Ysz Electrode, Shizhong Wang, Yi Zhang Yahong Jiang, Jingwang Yan, Wenzhao Li

Journal of Electrochemistry

Electrochemical reaction of oxygen on the La 0.8 Sr 0.2 MnO 3/YSZ electrode has been investigated in detail with AC impedance. The results demonstrated that the rate determining step(rds) of the reaction varies with the temperature, oxygen partial pressure and overpotential applied. At open circuit potential, the rds is the dissociative adsorption of oxygen on the LSM surface. A large number of electron holes are generated at high anodic overpotentials, while oxygen vacancies are formed at high cathodic overpotentials. The formation of the electron holes results in the electronic conduction of the YSZ electrolyte and the extension of the electrochemical …

The Hydrogen Evolution Reaction On The Hydrogen Storage Alloy Electrode, Shigang Lu, Qun Li, Qingguo Liu, Chun Lu, Bing Dang

Journal of Electrochemistry

The hydrogen evolution reaction was studied in 1 mol/L KOH solution on the hydrogen storage alloy Mm(NiCoMnAl) 5 electrode using open circuit potential decay and ac impedance technique. The reaction was found to proceed by the Volmer(discharge)-Tafel(recombination)mechanism. The measured overpotential η can be subdivided into two components η 1 and η 2 corresponding to the elementary Volmer and Tafel reaction. The Faradaic impedance was analyzed and characterized by the Volmer reaction. Then the exchange current density was evaluated . It was founded that the activity of hydrogen storage alloy electrode for the hydrogen evolution reaction was similar to that of …

Li Ion Intercalation Charactersitic Of Gas Coke, Zhenghua Deng, Xiaozheng Zhang, Xiaobing Ding, Mianzhong Chen, Weiguo Xie, Guoxiang Wan

Journal of Electrochemistry

A novel of carbon gas coke prepared from natural gas by thermoplasma technology has been studied. The cyclic voltametry and charge discharge test for the Li/gas coke cell demonstrated that this gas coke material has a good performance of the Li ion intercalation characteristic. X ray diffraction pattern of the gas cokeis showed that the structure of gas coke is similar to the graphite and collapsed from order to disorder during the charge discharge cycles. The gas coke electrode give rise to a new diffraction peak at a low angle after intercalating Li ion and a reversible capacity with 235 …

Photoelectrochemical Studies On Nanoporous Tio 2/Pan Film Electrode, Minsheng Liu, Yanzhong Hao, Xuebin Qiao, Maizhi Yang, Shengmin Cai

Journal of Electrochemistry

The photon to electricity conversion process of nanoporous TiO 2/PAn film electrode was studied in electrolytes with and without redox couple by using the photocurrent action spectra and potential dependence of photocurrent. It is concluded that the nanoporous TiO 2/PAn film electrode has a structure of duplex n type semiconductor layers. The band gap of PAn film is 2.88eV.The TiO 2 nanoporous film electrode modified by PAn can extend the range of optical absorption into visible and infrared region and effectively increase the photocurrent in the visible and infrared region. The photocurrent threshold shifts to>600nm and conversion efficiency of …

Putative Light Scalar Nonet, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino

Physics - All Scholarship

We investigate the "family" relationship of a possible scalar nonet composed of the a_0(980), the f_0(980) and the \sigma and \kappa type states found in recent treatments of \pi\pi and \pi K scattering. We work in the effective Lagrangian framework, starting from terms which yield "ideal mixing" according to Okubo's original formulation. It is noted that there is another solution corresponding to dual ideal mixing which agrees with Jaffe's picture of scalars as qq\bar q \bar q states rather than as q\bar q states. At the Lagrangian level there is no difference in the formulation of the two cases (other …

Integrating The Nation's Environmental Monitoring And Research Networks And Programs, James R. Gosz, Pete Murdoch

Long Term Ecological Research Network

An Exercise to Demonstrate the Value of Index Areas in a National Network: A Report Prepared for the Office of Science and Technology Policy (OSTP).

The Environmental Monitoring Team, a team of Federal scientists and program managers, was convened by the CENR Steering Committee and given the charge "to develop a national framework for integration and coordination of environmental monitoring and related research through collaboration and building upon existing networks and programs". Two of the recommendations for a National Environment Monitoring Framework were; 1) evaluate alternatives for selecting the number and distribution of "index areas", including stratification by ecoregion in …

Quadrilaterals Subdivided By Triangles In The Hyperbolic Plane, Dawn M. Haney, Lori T. Mckeough

Mathematical Sciences Technical Reports (MSTR)

In this paper, we consider triangle-quadrilateral pairs in the hyperbolic plane which “kaleidoscopically” tile the plane simultaneously. These tilings are called divisible tilings or subdivided tilings. We restrict our attention to the simplest case of divisible tilings, satisfying the corner condition, in which a single triangle occurs at each vertexof the quadrilateral. All possible such divisible tilings are catalogued as well as determining the minimal genus surface on which the divisible tiling exists. The tiling groups of these surfaces are also determined.

Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya Garashchuk, David J. Tannor

Faculty Publications

Investigates the correlation function formulation for the state selected total reaction probability. Discussion of the wave packet propagation; Derivation of the correlation function expression for the N[sub alpha](E); Application of quantum-mechanical and Herman-Kluk propagation methods.

Semi-Automated Extraction Of Digital Objective Prism Spectra, Coryn A.L. Bailer-Jones, Ted Von Hippel, Mike Irwin

Publications

We describe a method for the extraction of spectra from high dispersion objective prism plates. Our method is a catalogue driven plate solution approach, making use of the Right Ascension and Declination coordinates for the target objects. In contrast to existing methods of photographic plate reduction, we digitize the entire plate and extract spectra off-line. This approach has the advantages that it can be applied to CCD objective prism images, and spectra can be re-extracted (or additional spectra extracted) without having to re-scan the plate. After a brief initial interactive period, the subsequent reduction procedure is completely automatic, resulting in …

Search For Selectron And Squark Production In E+P Collisions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, 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

We have searched for the production of a selectron and a squark in e+p collisions at a center-of-mass energy of 300 GeV using the ZEUS detector at HERA. The selectron and squark are sought in the direct decay into the lightest neutralino in the framework of supersymmetric extensions to the Standard Model which conserve R-parity. No evidence for the production of supersymmetric particles has been found in a data sample corresponding to 46.6 pb-1 of integrated luminosity. We express upper limits on the product of the cross section times the decay branching ratios as excluded regions in the parameter space …

The Tubular Phase Of Self-Avoiding Anisotropic Crystalline Membranes, Mark Bowick, Alex Travesset

Physics - All Scholarship

We analyze the tubular phase of self-avoiding anisotropic crystalline membranes. A careful analysis using renormalization group arguments together with symmetry requirements motivates the simplest form of the large-distance free energy describing fluctuations of tubular configurations. The non-self-avoiding limit of the model is shown to be exactly solvable. For the full self-avoiding model we compute the critical exponents using an epsilon-expansion about the upper critical embedding dimension for general internal dimension D and embedding dimension d. We then exhibit various methods for reliably extrapolating to the physical point (D=2,d=3). Our most accurate estimates are nu=0.62 for the Flory exponent and zeta=0.80 …

Applications Of Parallel I/O, Ron Oldfield, David Kotz

Computer Science Technical Reports

Scientific applications are increasingly being implemented on massively parallel supercomputers. Many of these applications have intense I/O demands, as well as massive computational requirements. This paper is essentially an annotated bibliography of papers and other sources of information about scientific applications using parallel I/O. It will be updated periodically.

The Future Of Computing: Cyberspace, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper traces trends in the technological advances of computer and communication systems and examines the promises of the Information Society: global information sharing; and, intelligent decision-support. The technological developments that will lead to the realization of Cyberspace, an information rich environment in which virtual reality capabilities couple directly to the human senses, is explored in terms of five essential components: information processing requirements; communication networks; computing devices (i.e., platforms); hardware and software user-interfaces; and, the meaningful representation of information.

Attention is drawn to the critical role played by information representation in a Cyberspace environment. The author argues …

The Round Table Model: A Web-Oriented, Agent-Based Approach To Decision-Support Applications, Kym J. Pohl, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Not unlike King Arthur relying on the infamous Round Table as the setting for consultation with his most trusted experts, agent-based, decision-support systems provide human decision makers with a means of solving complex problems through collaboration with collections of both human and computer-based expert agents. The Round Table Framework provides a formalized architecture together with a set of development and execution tools which can be utilized to design, develop, and execute agent-based, decision-support applications. Based on a three-tier architecture, Round Table incorporates forefront technologies including distributed-object servers, inference engines, and web-based presentation to provide a framework for collaborative, agent-based decision …

Collaborative Decision Support Systems For Facility Management, Arthur J. Chapman, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Agent-based collaborative decision support is a methodology of utilizing domain specific intelligent systems, interacting in a common environment, to partner with one or more human decision makers to reach a consensus solution to a complex problem. An example is the recently developed Collaborative Infrastructure Assessment Tool (CIAT) that provides a collaborative planning facility management tool in support of military pier and port management. This methodology is applicable to many similar dynamic facility management problems where the complexity of issues and the number of decision makers result in the need for domain specific agents, a common view of the data, and …

Mid- And Low-Latitude Prompt-Penetration Ionospheric Zonalplasma Drifts, Bela G. Fejer, L. Scherliess

Bela G. Fejer

We have used ion drift observations from the DE-2 satellite to determine the latitudinal variation and the temporal evolution of mid- and low-latitude prompt penetration zonal plasma drifts driven by magnetospheric electric fields. Our results indicate that sudden increases in convection lead to predominantly westward perturbation drifts which decrease equartorwards and have largest amplitudes in the dusk-midnight sector. The diurnal perturbation drift patterns shift to later local times with increasing storm time and decay to new quasi-equilibrium values in about 2 hours, as the ring current readjusts to the new polar cap potential. The daily and latitudinal variations and temporal …

Measured Stark Widths And Shifts Of Several Niii Sectral Lines: Temperature Dependence, Stevan Djenize, Vladimir Milosavljevic

Articles

Stark parameters (width and shift) of four doubly ionized nitrogen spectral lines, that belong to 3s-3p and 3p-3d transitions (lower multiplets), have been measured in a linear pulsed, low pressure, arc discharge in the nitrogen-oxygen and helium-nitrogen-oxygen plasmas in a (30 000 - 54 000) K electron temperature and a (0.75 10²³ - 2.8 10²³) electron density ranges. The measured values have been compared to the existing experimental and calculated data.