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Articles 32161 - 32190 of 34601

Full-Text Articles in Physical Sciences and Mathematics

Effect Of Molecular Weight On Polyphenylguinoxaline Properties, Brian J. Jensen Jan 1983

Effect Of Molecular Weight On Polyphenylguinoxaline Properties, Brian J. Jensen

Dissertations, Theses, and Masters Projects

No abstract provided.


The Theory And Synthesis Of [2.2.2] Propellane, Theodore Mark Prociv Jan 1983

The Theory And Synthesis Of [2.2.2] Propellane, Theodore Mark Prociv

Dissertations, Theses, and Capstone Projects

INDO calculations indicated that the triplet state of dimethylene cyclohexane could rearrange to gometrically relaxed triplets which should collapse preferentially to the ground state [2.2.2] Propellane. A mercury sensitized photolysis of the dimethylene cyclohexane did in fact result in detectable quantities of the propellane, trapped as 1,4 dibromobicyclo octane. Synthesis of 1,4 dibromobicyclo octane and 1,1,6,6 tetradeuterodimethylene-cyclohexane are presented in the dissertation. Included in the dissertation are the results of INDO calculations of various propellane isomers having nitrogens and borons in the bridgehead positions.


Internal Rotation Effects And Nuclear Hyperfine Structure In The Microwave Spectrum Of Propyne-Hf, Roger E. Bumgarner Jan 1983

Internal Rotation Effects And Nuclear Hyperfine Structure In The Microwave Spectrum Of Propyne-Hf, Roger E. Bumgarner

Masters Theses

The microwave spectrum of the weakly bound propyne-HF/DF complex in the region between 6 and 16 GHz was analyzed. The spectrum was characteristic of a distorted T-shaped asymmetric top exhibiting torsional splitting caused by a low barrier to internal rotation of the methyl top relative to the propyne-HF frame. Deuterium substitution of HF confirms that the acid proton of HF is located between the F atom and the propyne triple bond. The spectroscopic constants given below are consistent with the fluorine atom being displaced toward the methyl group from a line perpendicular to and bisecting the propyne triple bond, suggesting …


Synthesis And Reactions Of Aromatic Ethers As Model Compounds For Coal, James Nicolas Ong Sy Jan 1983

Synthesis And Reactions Of Aromatic Ethers As Model Compounds For Coal, James Nicolas Ong Sy

Masters Theses

o-Anisic acid and o-ethoxybenzoic acid were reacted with pyridine hydriodide in pyridine at 115° for 3 days to yield 81% and 18% salicylic acid respectively. o-Anisic acid with KI in pyridine at 115° for 3 days gave 58% salicylic acid while o-anisic acid with LiI·3H2O in pyridine at 85° for 3 days gave 54% salicylic acid. p-Anisic acid and o-phenoxybenzoic acid did not undergo cleavage reactions with pyridine hydriodide under similar conditions.

Beta-methylnaphthyl beta-naphthyl ether(I) or alpha-methylnaphthyl alpha-naphthyl ether(II) with pyridine hydriodide in pyridine at 100-115° for 3 days showed no cleavage. Ether I …


Preparation And Characterization Of Tertiary Phosphine Carbonyl Ruthenium (0) Complexes, Joann C. Bady Jan 1983

Preparation And Characterization Of Tertiary Phosphine Carbonyl Ruthenium (0) Complexes, Joann C. Bady

Masters Theses

Dichlorocarbonyltris(triphenylphosphine)ruthenium (II), Ru(CO)(Cl)2(Ph3P)3, was prepared by modification of a procedure reported to yield the dimer, (Ru(CO)(Cl)2(Ph3P)2)2. Dissolution of Ru(CO)(Cl)2(Ph3P)3 in acetonitrile resulted in loss of triphenylphosphine and dimer formation.

Metathesis of Ru(CO)(Cl)2(Ph3P)3 in hexane with excess tertiary phosphine yielded complexes of the type Ru(CO)(Cl)2-(R2R′P)3 where R2R′P is Ph2MeP or PhMe2P. 1H and 31p nmr spectra of these materials showed that two phosphines are …


Analysis Of The Surface Polysaccharides Of R. Trifolii Su843 And Its Sym Plasmid Alterated Mutants, Jauh-Lin Duh Jan 1983

Analysis Of The Surface Polysaccharides Of R. Trifolii Su843 And Its Sym Plasmid Alterated Mutants, Jauh-Lin Duh

Masters Theses

The Rhizobium trifolii polysaccharides from SU843 and mutants--HC843(pBR1AN), HC843, 8002--in which the sym plasmid is replaced, absent, or mutated by transposon Tn5 were isolated. The surface polysaccharides of genetically altered mutants were compared quantitatively and qualitatively with one another and with the parent strain. The interpretation of these results is discussed in relation to the function of Rhizobium surface polysaccharides in the symbiotic process. The symbiotic ability of SU843 and mutant strains is as follows: (a) SU843, nod+, fix+; (b) mutant 8002, roa+ (still attaches to root hair), hac-, nod-; (c) …


A Study Of The Electroless Plating Of Sn Onto A Die-Cast Aluminum Alloy, Ann-Tinn Shen Jan 1983

A Study Of The Electroless Plating Of Sn Onto A Die-Cast Aluminum Alloy, Ann-Tinn Shen

Masters Theses

"A tin layer was immersion plated onto a zinc-silicon containing aluminum alloy by using a potassium stannate solution. Conventional aluminum pretreatment was used before immersion plating.

Effects of immersion time with immersion tin thickness and Al-Sn adhesion were studied. Conditions of subsequent Sn-Pb electroplating on Sn plated aluminum samples were investigated.

SEM (scanning electron microscope) and x-ray energy dispersion studies were extensively used on samples of each stage"--Abstract, page ii.


Assessment Of Chlorination By Human Neutrophils, Thomas Goyne, Christopher Foote, Robert Lehrer Dec 1982

Assessment Of Chlorination By Human Neutrophils, Thomas Goyne, Christopher Foote, Robert Lehrer

Thomas Goyne

No abstract provided.


Crystal Structures Of Trans-Acetyldicarbonyl- (Eta5-Cyclopentadienyl)(Dimethylphenylphosphane)- Molybdenum(Ii) And Trans-Acetyldicarbonyl- (Eta5-Cyclopentadienyl)(Ethyldiphenylphosphane)- Molybdenum(Ii), Matthew T. Whited, Gretchen E. Hofmeister, Connor J. Hodges, Laramie T. Jensen, Samuel H. Keyes, Aurapat Ngamnithiporn, Daron E. Janzen Dec 1982

Crystal Structures Of Trans-Acetyldicarbonyl- (Eta5-Cyclopentadienyl)(Dimethylphenylphosphane)- Molybdenum(Ii) And Trans-Acetyldicarbonyl- (Eta5-Cyclopentadienyl)(Ethyldiphenylphosphane)- Molybdenum(Ii), Matthew T. Whited, Gretchen E. Hofmeister, Connor J. Hodges, Laramie T. Jensen, Samuel H. Keyes, Aurapat Ngamnithiporn, Daron E. Janzen

Daron E Janzen, Ph.D.

No abstract provided.


Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Acrivos Dec 1982

Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Acrivos

Faculty Publications, Chemistry

We have measured XANES (X-ray Absorption Near Edge Spectra) near the Re Li(i=l,II,III) edges in (TMTTF)2Re04 and (TMTSeF)2Re04 and the Se K edge in the latter compound. An important dependence of the XANES at the Se K edge on the polarization of the incident beam with respect to the crystal axes was observed, whose interpretation can give information on the symmetry of the unoccupied conduction band states. The positions of the Re L edges were compared with those in several .inorganic compounds containing Re in various oxidation states, and were found to be, within experimental error, the same as those …


Centers Of Polymer Research; Polymer Science In The South And West Of Japan, Otto Vogl, T. Kunitake, J. Kiji Dec 1982

Centers Of Polymer Research; Polymer Science In The South And West Of Japan, Otto Vogl, T. Kunitake, J. Kiji

Otto Vogl

No abstract provided.


Symposium On Functional Polymers, Kunming, Yunnan, People’S Republic Of China, Otto Vogl, K. Takemoto Dec 1982

Symposium On Functional Polymers, Kunming, Yunnan, People’S Republic Of China, Otto Vogl, K. Takemoto

Otto Vogl

No abstract provided.


Calculated Electrocapillary Curve For A Molten Salt, Jerry Goodisman, S Amokrane Dec 1982

Calculated Electrocapillary Curve For A Molten Salt, Jerry Goodisman, S Amokrane

Chemistry - All Scholarship

If bulk properties of simple molten salts may be reasonably well understood in terms of the primitive model, the situation with respect to surface properties is less satisfactory. It has been shown that a simple model for the distributions at the free surface of a molten salt can give surface tension and surface energy in reasonable accord with experiment, provided that a factor guaranteeing local electroneutrality is introduced. In this model, properties are given in terms of bulk-salt distribution functions, for which the primitive model is used. The present work extends this model to the electrocapillary curve, i.e., variation of …


Kinetic And Spectral Studies Of Cobalt (Ii) -4, 4’, 4’’, 4’’’ –Tetrasulfophthalocyanine With Sodium Cyanide In Aqueous Solution, Pablo J. Diaz Cruz Dec 1982

Kinetic And Spectral Studies Of Cobalt (Ii) -4, 4’, 4’’, 4’’’ –Tetrasulfophthalocyanine With Sodium Cyanide In Aqueous Solution, Pablo J. Diaz Cruz

Masters Theses & Specialist Projects

Kinetic studies of the cobalt (II)-4, 4’, 4’’, 4’’’-tetrasulfophtalocyanine and cyanide system were performed under argon and in air over temperature ranges of 294-314°K and 294-324°K, respectively. Two reactions were detected under argon. One was quite rapid and was followed on the stopped-flow apparatus. The results are consistent with the perturbation of a monomer-dimer equilibrium. The second reaction was slow enough to be followed spectrophotometrically on the Cary Model 14 spectrophotometer. The second order rate constant of 0.11 M-1 sec-1 at 294°K has been attributed to the rate of substitution of the second cyanide addition to a dye-cyanide …


Kinetics Of Ternary Complex Formation Reactions Of The Nickel(Ii) Complexes Of Ethylenediaminediacetate And Triethylenetetramine With Bidentate Donors, Lawrence H. Kolopajlo Dec 1982

Kinetics Of Ternary Complex Formation Reactions Of The Nickel(Ii) Complexes Of Ethylenediaminediacetate And Triethylenetetramine With Bidentate Donors, Lawrence H. Kolopajlo

Dissertations

The stopped-flow technique was used to measure rate constants for ternary complex formation involving both NiEDDA and Ni(trien)('2+), and bidentate donors. The reactions of both NiEDDA and Ni(trien)('2+) with bipy, phen, en, and sar were studied. In addition the reaction of NiEDDA and gly was studied. The reactions were of the first-order with respect to either nickel complex, and with respect to enH('+), bipy, and phen. The reactions involving phen and bipy were independent of pH and were reversible. The formation rate constants for the systems containing diamine reactants are as follows:

(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)

For …


Determination Of Organophosphorus Compounds By Hplc With Post-Column Photochemical Degradation Followed By The Formation Of Reduced Heieropolymolybdate, Stephen R. Priebe Dec 1982

Determination Of Organophosphorus Compounds By Hplc With Post-Column Photochemical Degradation Followed By The Formation Of Reduced Heieropolymolybdate, Stephen R. Priebe

Dissertations

A novel method for the determination of organophosphorus (OP) compounds by HPLC with post-column photochemical and chemical derivatization reactions has been developed. The OP compounds eluted from the column were photochemically degraded to orthophosphate by the use of a 450 W xenon lamp in conjunction with an auxiliary photodegradation reagent. The photodegradation reaction was studied extensively by means of batch irradiations with triethylphosphate as a model compound. The effects of the initial concentrations of triethylphosphate and ammonium peroxydisulfate, and of varying the pH of the reaction medium were determined. A survey of potential interferences was performed. Copper(II) ion was found …


Oxidation Activity Of Catalyst 3-7a Toward Formaldehyde, Hydrogen Cyanide, And Some Alkane Gases, John Kawas Dec 1982

Oxidation Activity Of Catalyst 3-7a Toward Formaldehyde, Hydrogen Cyanide, And Some Alkane Gases, John Kawas

Masters Theses & Specialist Projects

The activity of Catalyst 3-7A toward the oxidation of formaldehyde, hydrogen cyanide, methane, propane, and isobutene was examined at temperatures between 25°C and 400°C. The catalyst consists of palladium(II) and copper (II) salts impregnated on an alumina support. The oxidation measurements were made primarily with gas chromatographs, although form aldehyde and hydrogen cyanide were also examined using the colorimetric fushsin method and Liebig titrations, respectively. Catalyst 3-7A demonstrated appreciable activity toward the oxidation of all gases studied except formaldehyde where there was no evidence of oxidation. The latter result is quite unexpected since aldehydes are more easily oxidized than alkanes. …


Centers Of Polymer Research; Polymer Science In The Nagoya Area, Otto Vogl, M. Nagasawa, Y. Yamashita Nov 1982

Centers Of Polymer Research; Polymer Science In The Nagoya Area, Otto Vogl, M. Nagasawa, Y. Yamashita

Otto Vogl

No abstract provided.


U.S.-Swedish Workshop On Photodegradation And Photostabilization Of Polymers, Otto Vogl, Bengt Ranby Nov 1982

U.S.-Swedish Workshop On Photodegradation And Photostabilization Of Polymers, Otto Vogl, Bengt Ranby

Otto Vogl

No abstract provided.


Spermidine-Condensed Phi X174 Dna Cleavage By Micrococcal Nuclease: Torus Cleavage Model And Evidence For Unidirectional Circumferential Dna Wrapping., Kenneth A. Marx, Thomas C. Reynolds Nov 1982

Spermidine-Condensed Phi X174 Dna Cleavage By Micrococcal Nuclease: Torus Cleavage Model And Evidence For Unidirectional Circumferential Dna Wrapping., Kenneth A. Marx, Thomas C. Reynolds

Dartmouth Scholarship

Spermidine-condensed phi X174 replicative form (RF) II DNA was digested with micrococcal nuclease to yield seven identifiable DNA bands forming an arithmetic fragment-length series. The DNA monomer unit length was found to be 780 +/- 80 base pairs. This result is most consistent with a proposed model for micrococcal nuclease cleavage of a DNA torus organized by the unidirectional, circumferential wrapping of B-geometry DNA. By a topological consideration, the blunt-end-rod-fusion model for torus formation [Eickbush, T. H. & Moudrianakis, E. N. (1978) Cell 13, 295-306] is shown to be inconsistent with our empirical solution results. We propose a continuous, circumferential …


Excited States And Photochemistry Of Saturated Molecules. 11. Potential Energy Surfaces In Low-Lying States Of Ethane, James W. Caldwell, Mark S. Gordon Oct 1982

Excited States And Photochemistry Of Saturated Molecules. 11. Potential Energy Surfaces In Low-Lying States Of Ethane, James W. Caldwell, Mark S. Gordon

Mark S. Gordon

Ab initio calculations at both the restricted Hartree-Fock (RHF) and singly excited configuration interaction (SEC I) levels have been carried out on sections of the potential energy surfaces for a number of low-lying excited singlet electronic states of ethane. All vertical states below the first ionization potential are predominantly Rydberg in character, as are all minima detected on the potential energy surfaces. The lowest 1Eg state is predicted to have only a very small (""" 1 kcal/mol) barrier separating its minimum-energy structure from the 1A" ethylidene + 1 ~/ H2 products. Since the vertical Eg molecule has more than enough …


Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part Ii, Otto Vogl, T. Otsu, K. Hatada Oct 1982

Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part Ii, Otto Vogl, T. Otsu, K. Hatada

Otto Vogl

No abstract provided.


Self‐Consistent Molecular Orbital Methods. Xxiii. A Polarization‐Type Basis Set For Second‐Row Elements, Michelle M. Francl, William J. Pietro, Warren J. Hehre, J Stephen Binkley, Mark S. Gordon, Douglas J. Defrees, John A. Pople Oct 1982

Self‐Consistent Molecular Orbital Methods. Xxiii. A Polarization‐Type Basis Set For Second‐Row Elements, Michelle M. Francl, William J. Pietro, Warren J. Hehre, J Stephen Binkley, Mark S. Gordon, Douglas J. Defrees, John A. Pople

Chemistry Faculty Research and Scholarship

The 6‐31G* and 6‐31G** basis sets previously introduced for first‐row atoms have been extended through the second‐row of the periodic table. Equilibrium geometries for one‐heavy‐atom hydrides calculated for the two‐basis sets and using Hartree–Fock wave functions are in good agreement both with each other and with the experimental data. HF/6‐31G* structures, obtained for two‐heavy‐atom hydrides and for a variety of hypervalent second‐row molecules, are also in excellent accord with experimental equilibrium geometries. No large deviations between calculated and experimental single bond lengths have been noted, in contrast to previous work on analogous first‐row compounds, where limiting Hartree–Fock distances were in …


Separation Of Piperylene Concentrate Via Metathesis Catalysis, Donald R. Allred Oct 1982

Separation Of Piperylene Concentrate Via Metathesis Catalysis, Donald R. Allred

Retrospective Theses and Dissertations

Diolefin metathesis, using a Re2O7 catalyst, failed to show a reactivity difference due to conjugation of double bonds. However, the same system allows reaction of pentadiene while not affecting cyclopentene yielding a successful reaction ΓÇô separation scheme for a piperylene concentrate mixture.


Excluded-Volume Effect On Quasi-Elastic Light Scattering By Flexible Macromolecules, Genzo Tanaka, Walter H. Stockmayer Oct 1982

Excluded-Volume Effect On Quasi-Elastic Light Scattering By Flexible Macromolecules, Genzo Tanaka, Walter H. Stockmayer

Dartmouth Scholarship

First-order perturbation expressions are developed for the first cumulant (initial time derivative) of the dynamic structure factor observable by photon-correlation measurements of the light scattered by flexible chain molecules in solution. A dimensionless coefficient C, which measures the initial departure of the first cumulant from proportionality to the square of the scattering vector, is found to be only slightly altered by excluded-volume effects.


Gas-Phase Photolysis Of 2,2-Dimethylbutane, 2,2,3-Trimethylbutane, 2,2,3-Trimethyl-2-Silabutane, And 2,2,3,3-Tetramethyl-2-Silabutane At 147 Nm, Daryl J. Doyle, S. K. Tokach, Mark S. Gordon, Robert D. Koob Sep 1982

Gas-Phase Photolysis Of 2,2-Dimethylbutane, 2,2,3-Trimethylbutane, 2,2,3-Trimethyl-2-Silabutane, And 2,2,3,3-Tetramethyl-2-Silabutane At 147 Nm, Daryl J. Doyle, S. K. Tokach, Mark S. Gordon, Robert D. Koob

Mark S. Gordon

The 147-nm photolyses of 2,2-dimethylbutane, 2,2,3-trimethylbutane, 2,2,3-trimethyl-2-silabutane (isopropyltrimethylsilane), and 2,2,3,3-tetramethyl-2-silabutane (tert-butyltrimethylsilane) are reported. In addition, the mercury-sensitized photolyses of i-C4H10, trimethylsilane, and mixtures of i-C4H10 and trimethylsilane are reported which give disproportionation to combination (D/C) ratios of 2.1 ::1::0.2 and 0.28::1::0.05 for (CH3) 3C + (CH3) 3C and (CH3)gSi + (CH3)gSi, respectively, and D/C ratios of 1.86::1:: 0.15 and 0.55 ::1:: 0.08 for (CH3)gC + (CH3)aSi to form 2-methyl-2-silapropene and i-C4H8, respectively. With the completion of this work, several trends and generalizations can be drawn concerning the importance of various processes in linear vs. branched alkanes and alkylsilanes. These conclusions …


Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part I, Otto Vogl, T. Otsu, K. Hatada Sep 1982

Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part I, Otto Vogl, T. Otsu, K. Hatada

Otto Vogl

No abstract provided.


Isolation And Characterization Of The Serum Ferroxidase Inhibitor, Melissa Page Calisch Sep 1982

Isolation And Characterization Of The Serum Ferroxidase Inhibitor, Melissa Page Calisch

Master's Theses

strong evidence suggests that the serum ferroxidases (ceruloplasmin andferroxidase II) promote the formation of Fe-III transferrin and thereby stimulate the turnover of iron from tissue stores. Ceruloplasmin is the major ferroxidase in human serum; whereas, ferroxidase II accotmts for an increased proportion of the activity in less highly developed animals. A large fold increase in total ferroxidase II activity was observed when both human and rabbit sera were subjected to gel-filtration on sephadex G-200. This indicated that whole serum might contain a potent inhibitor of ferroxidase II. Such an inhibitor has been isolated and purified to homogeneity by a combination …


Effects Of Polar Substituents On Carbon-Silicon Multiple Bonds, Mark S. Gordon Aug 1982

Effects Of Polar Substituents On Carbon-Silicon Multiple Bonds, Mark S. Gordon

Mark S. Gordon

The results of ab initio calculations on the effects of fluorine and lithium substitution on silaethyne and silaethylene and their isomers are presented. It is found that fluorine has a strong stabilizing effect when attached to silicon. This results in the predictions (a) that a distorted 1-fluoro-1-silaethyne is the most stable structure of HCSiF and (b) that 1,1-difluoro- 1-silaethylene is much lower in energy than 1,2-difluoromethylsilylene. Approximate correlation corrections are added to study the HC~iF - FHC=Si and HC==SiLi - LiHC=Si potential energy surfaces.


Centers Of Polymer Research; Polymer Science In Tokyo, Japan, Part Iii: Suburban Area, Otto Vogl, I. Uematsu, A. Abe Aug 1982

Centers Of Polymer Research; Polymer Science In Tokyo, Japan, Part Iii: Suburban Area, Otto Vogl, I. Uematsu, A. Abe

Otto Vogl

No abstract provided.