Physical Sciences and Mathematics Commons^™

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.

An Investigation On The Corrosion Potential Imaging At The Interface Of Concrete/Reinforcing Bar In Corrosion Media, Rong-Zong Hu, Chang-Jian Lin, Xiang Zhou, Jian-Guang Tan, Xiong-Chao Zhao

Journal of Electrochemistry

The iron array electrode covered with concrete as a new electrochemical technique is applied to map the potential imaging and to investigate on the iron electrode corrosion process under concrete: In Cl - solution the corrosion of the iron array electrode covered with concrete had been prevented for a short term since the concrete protection, but the corrosion still occurreed and developed after immersed for a long time. In SO 4 2- solution although the sample had being immersed for a long time and the concrete was possibly broken, the corrosion did not develop. In Cl - solution the corrosion …

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 …

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.

Effects Of Temperature On The Proton Diffusion Of Doped Ni(Oh)_2, Jian-Hua Liu, Jing-Wu Yang, Zhi-Yuan Tang

Journal of Electrochemistry

The Chronoamperometry of powder spherical Ni(OH) 2 microelectrode was used to study the proton diffusion coefficients of Ni(OH) 2. The proton diffusion coeefficients and the apparent diffusion active energy in anode and cathode processes at different temperature were obtained. Compared with pure Ni(OH) 2, the apparent diffusion active energy( E a) of Ni(OH) 2 doped with Co and Co+Zn was decreased and the diffusion constant( D o) was increased in the anode and the cathode processes, respectively, the effect of Co was greater. In contrast, for Ni(OH) 2 doped with Zn, its E a was increased and D o was …

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 …

The Influence Of Surface Diffusion Of Adsorbed Intermediate On Hydrogen Evolution Reaction At Pt/Nafion Composite Electrodes, Wei-Yi Tu, Lei Su, Wen-Jun Liu, Bing-Liang Wu

Journal of Electrochemistry

The decrease of over_potential of hydrogen evolution reaction at Pt black powder/Nafion microelectrode, comparing that of the Pt microdisk/Nafion electrode, was evident from the polarization curves of the Pt microdisk/Nafion electrode, platinized Pt micrdisk/Nafion electrode and Pt black powder/Nafion microelectrode. It is also evidenced by a plane Pt electrode with an additional free Pt surface. The surface diffusion and the surface recombination reaction of the adsorbed intermediate at the free surface of the Pt particles were supposed. It is an additional reaction path that induced the decrease of the concentration of the adsorbed intermediate. Thereby, the over_potential decreased.

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.

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 …

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 …

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)].

Phage Therapy : An Alternative To Antibiotics, Maria A. Appeaning

Electronic Dissertations and Theses

Bacteria resistant to most or all available antibiotics are causing increasingly serious problems and raising widespread fears of returning to a pre-antibiotic era of untreatable infections and epidemics. Despite intensive work by drug companies, no new classes of antibiotics have been found in the last 30 years . There are hopes that the newfound ability to sequence entire microbial genomes and to determine the molecular bases of pathogenicity will open new avenues for treating infectious disease, but other approaches are also being sought with increasing fervor. One result is a renewed interest in the possibilities of bacteriophage (phage) therapy - …

Visual Test Using Color Frequency Doubling, Scott Whittenburg

Chemistry Faculty Publications

A novel psychophysical visual test is proposed for testing a person for glaucoma, and based on the discovery that a frequency doubling phenomenon is produced by isoluminent color visual stimuli. More specifically, it is proposed to construct a visual stimulus for which alternating colors in a grating pattern is the only basis for producing the frequency doubling phenomenon. That is, the colors are of the same luminance or intensity level, i.e., isoluminent, but each grating or pattern alternates from one color to another. Preferably, the colors are complementary color pairs, such as blue and yellow.

Rotational Structure Of Extremely Floppy Van Der Waals Complexes: Adiabatic Separation Of Angular And Radial Motion, P. Daniel Ward

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The adiabatic or Born-Oppenheimer approximation is often used in molecular calculations to simplify the solution to the Schrödinger equation. The basis of the approximation is the large difference in the relative motions of the nuclei and electrons in the molecule—the electrons are able to respond almost instantly to the movements of the nuclei. Thus, the nuclei may be regarded as being fixed in a certain position and the Schrödinger equation can then be solved using the potential obtained by solving the electronic problem at fixed nuclear configuration.

A similar argument can be used to decouple the angular and radial motions …

Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogenase is the enzyme that catalyzes the reduction of nitrogen to ammonia in a reaction requiring MgATP hydrolysis. Two component proteins of nitrogenase are the iron protein (Fe protein) and the molybdenum-iron protein (MoFe protein).

Nitrogenase contains two nucleotide binding sites. During catalysis, the Fe protein binds two MgATP first. The conformational changes induced upon MgATP binding allow the Fe protein to associate with the MoFe protein. After the formation of the Fe protein-MoFe protein complex, a single electron is transferred from the Fe protein to the MoFe protein, an event that is coupled to MgATP hydrolysis in the Fe …

Quantitative Measurement Of Guest–Host Interactions In Supramolecular Systems: A Comparative Brillouin Scattering Study Of The Dianin’S Compound Clathrand And Two Of Its Isostructural Clathrates, C.A. Sandstedt, D. Michalski, Craig J. Eckhardt

Craig J. Eckhardt Publications

Single, isomorphous crystals of the guest-free clathrand of Dianin’s compound and two of its clathrates containing two ethanols and a heptanol, respectively, have been studied by Brillouin scattering to obtain their complete elastic constant tensors. The values found for individual elastic constants are related to microscopic interactions of the guests and host cage using the clathrand as the reference. Direct correlation of the interference of the guest heptanol molecule with the hexamer hydrogen-bonded network of the host cage to reduced stiffness of this clathrate is demonstrated. In contrast, the ethanol-containing clathrate is demonstrated to have negligible interaction of the guests …

Phorboxazole Synthetic Studies: The C3–C15 Bis-Oxane Segment, Patrick Bernard Greer, William Donaldson

Chemistry Faculty Research and Publications

The enantioselective synthesis of the C3–C15 bis-oxane segment of the phorboxazoles has been accomplished from 3-t-butyldiphenylsilyloxypropanal in 9 steps (>90% ee).

Synthesis Of Fluroxypyr For The Use On Broad Leaf Plants, Shena Ruane

Masters

Fluroxypyr, 1-methylheptyl (4-amino-3,5-dichloro-6-fluoro-2-pyridinyloxy) acetate is used for the control of annual broad leaf weeds in cereals and perennial rye grass. The objective of this work was to develop an economically viable process for the bench synthesis of an organic herbicide fluroxypyr and to scale up the reaction to two litres. This was carried out according to a technical bulletin received from Agriguard Ltd. In addition an investigation into the synthesis and characterisation of impurities formed and reported to be formed, in the reaction process was carried out. The process developed began with pentachloropyridine which on reaction with potassium fluoride in …

Charge-Transfer Bonding In Metal–Arene Coordination, S. M. Hubig, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

X-ray crystallographic structures of donor–acceptor complexes of aromatic hydrocarbons with transition metals are re-examined with the focus on the arene ligands. Thus, significant structural and electronic changes are revealed in the arene moiety due to coordination to the metal center including: (i) expansion of the aromatic six-carbon ring; (ii) endocyclic π-bond localization; (iii) distortion of the planarity (folding) of the arene ring; and (iv) shortening of the metal-arene bond distances. All structural features are characteristic of metal–arene (π- or σ-) complexes that exhibit various degrees of (metal-to-ligand) charge transfer. The concept of charge-transfer bonding not only explains the structural details …

A Magnetic And Crystallographic Study Of (Sm/Gd)₂(Fe/Si)₁₇CZ Solid Solutions, Peter C. Ezekwenna, G. K. Marasinghe, J. H. Nam, William Joseph James, William B. Yelon, M. Ellouze, Ph. I'Héritier

Chemistry Faculty Research & Creative Works

The crystallographic and magnetic properties of Sm_yGd_2-yFe_17-xSi_x (0 ≤ x ≤ 3 and y = 1 and 1.5) solid solutions and their interstitial carbides have been investigated using x-ray diffraction and magnetic measurements. The Sm_yGd_2-yFe_17-xSi_x samples crystallized in the rhombohedral Th₂Zn₁₇ structure with less than 5 mol % of impurities. The unit cells of the mixed rare-earth (R) samples are smaller than those of Sm₂Fe₁₇ and Gd₂Fe₁₇. The carbided samples contain up to a total of …

The Atomic And Magnetic Structure Of Ndmn(₆₋ₓ)Feₓge₆ Solid Solutions, J. Han, G. K. Marasinghe, William Joseph James, Muguo Chen, William B. Yelon, I. Dubenko, Naushad Ali

Chemistry Faculty Research & Creative Works

The magnetic and crystallographic properties of induction-melted NdMn_(6-x)Fe_xGe₆ intermetallics (x = 0, 1.0, and 1.5) in the temperature range of 30-475 K have been studied by x-ray and neutron diffraction techniques and SQUID measurements. All of the samples crystallized in the YCo₆Ge₆-type structure (P6/mmm). A small amount ( < 5 mol%) of Nd(MnFe)₂Ge₂ is present as an impurity. As expected, iron replaces manganese at the 3g site. The unit cell volume decreases slightly with increasing iron content at an average rate of 1.3% per substituted atom. Lattice parameters a and c contract at …

Retention Of Ionizable Compounds In Hplc, Rosario Lobrutto

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

Ac Susceptibility Of Sr3CuptXIr1-XO6: A Magnetic System With Competing Interactions And Dimensionality, S H. Irons, T D. Sangrey, K M. Beauchamp, M D. Smith, Hans Conrad Zur Loye

Faculty Publications

Sr₃CuPt_xIr_1-xO₆ has been cited as an example of a one-dimensional quantum spin chain with competing ferromagnetic and antiferromagnetic interactions. We have measured the ac susceptibility of Sr₃CuPt_xIr_1-xO₆ with x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, in magnetic fields of 0–60 kOe, and at temperatures down to 0.275 K. Our data show that the x=endpoint Sr₃CuIrO₆, exhibits long-range ferromagnetic order at T=20.1 K, contrary to results from dc susceptibility studies which indicated that it remained a one-dimensional ferromagnet to below 4 …

Fundamental Capillary Electrophoresis: An Evaluation Of Electrokinetic Sampling, Cindy Ann Mleziva Blake

Seton Hall University Dissertations and Theses (ETDs)

Capillary electrophoresis has become a powerful separation technique in fields of biochemical separations, inorganic ions, and chiral separations. The technique has experienced exponential growth since the historic publication of Zone Electrophoresis in Open-Tubular Glass Capillaries by Lukacs and Jorgenson in 1981. However, the use of capillary electrophoresis as a primary research analysis tool still remains to be seen in many pharmaceutical laboratories. One of the main reasons for this is that it remains difficult to validate CE methods using the criteria of quantitation and accuracy posed by the current government regulating agencies, as developed for high performance liquid chromatography and …

A Study Of The Solvolysis Reactions Of Tetrahydrofurfuryl Tosylate, Rebecca Centko '00

Honors Projects

The solvolysis of epoxycarbinyl substrates 1 has been the subject of several mechanistic studies. In spite of these investigations, it has not been established whether these solvolysis reactions proceed with anchimeric assistance from the epoxide oxygen and involve an oxabicyclobutonium ion intermediate or whether unassisted solvolysis occurs. Conflicting data in the literature suggest that the ability of the epoxide oxygen to provide anchimeric assistance is dependant upon structural and electronic features of the epoxycarbinyl substrate in question. The aim of this project was to study the nucleophilic substitution reactions of tetrahydrofurfuryl and tetrahydropyranyl sulfonates 2a and 2b as well as …

Role Of The Carbohydrate Moieties In Chiral Recognition On Teicoplanin- Based Lc Stationary Phases, Alain Berthod, Xianghong Chen, John P. Kullman, Daniel W. Armstrong, Francesco Gasparrini, Ilaria D'Acquarica, Claudio Villani, Angelo Carotti

Chemistry Faculty Research & Creative Works

For this study, we used the macrocyclic antibiotic teicoplanin, a molecule consisting of an aglycone peptide 'basket' with three attached carbohydrate (sugar) moieties. The sugar units were removed and the aglycone was purified. Two chiral stationary phases (CSPs) were prepared in a similar way, one with the native teicoplanin molecule and the other with the aglycone. Twenty-six compounds were evaluated on the two CSPs with seven RPLC mobile phases and two polar organic mobile phases. The compounds were 13 amino acids or structurally related compounds (including DOPA, folinic acid, etc.) and 13 other compounds (such as carnitine, bromacil, etc.). The …

Carbon Nanotube Atomic Force Microscopy Tips: Direct Growth By Chemical Vapor Deposition And Application To High-Resolution Imaging, Chin Li Cheung, Jason H. Hafner, Charles M. Lieber

Barry Chin Li Cheung Publications

Carbon nanotubes are potentially ideal atomic force microscopy probes because they can have diameters as small as one nanometer, have robust mechanical properties, and can be specifically functionalized with chemical and biological probes at the tip ends. This communication describes methods for the direct growth of carbon nanotube tips by chemical vapor deposition (CVD) using ethylene and iron catalysts deposited on commercial silicon-cantilever-tip assemblies. Scanning electron microscopy and transmission electron microscopy measurements demonstrate that multiwalled nanotube and single-walled nanotube tips can be grown by predictable variations in the CVD growth conditions. Force-displacement measurements made on the tips show that they …

The Role Of Monolayer Structure On Interfacial Phenomena, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

X-Ray Structure Of The Quinoprotein Ethanol Dehydrogenase From Pseudomonas Aeruginosa: Basis Of Substrate Specificity, Thomas Keitel, Annette Diehl, Tobias Knaute, John J. Stezowski, Wolfgang Hohne, Helmut Görisch

John J. Stezowski Publications

The homodimeric enzyme form of quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa ATCC 17933 crystallizes readily with the space group R3. The X-ray structure was solved at 2.6 Å resolution by molecular replacement. Aside from differences in some loops, the folding of the enzyme is very similar to the large subunit of the quinoprotein methanol dehydrogenases from Methylobacterium extorquens or Methylophilus W3A1. Eight W-shaped β-sheet motifs are arranged circularly in a propeller-like fashion forming a disk-shaped superbarrel. No electron density for a small subunit like that in methanol dehydrogenase could be found. The prosthetic group is located in the centre …