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CreatorTitleDescriptionSubjectDate
51 Ailion, David CharlesSelf-switching Q-damping circuit for reducing transmitter ringdown time in high power pulse NMRIn this paper we describe a circuit for reducing the transmitter ringdown time and thereby improving the recovery time in pulse NMR experiments. The circuit uses only solid state devices and requires no external switching. For transmitter voltages less than 0.5 V peak to peak the effective resista...Circuits; NMR experiments; Rf pulse1970
52 DeTar, CarletonO(2,1) decomposition of the equal-mass multipheripheral equation at t=0We extend the results of a group-theoretical analysis of the t=0 multiperipheral equation to the case t<0 for pairwise equal masses. Using variables discussed in a previous paper, we diagonalize the equation in the Bali-Chew-Pignotti (BCP) model with respect to the 0(2, 1) group and relate the solut...Multiperipheral model; Unitaries1970-05
53 Mattis, Daniel C.Role of phonons and band structure in metal-insulator phase transitionWe present a soluble model of electrons interacting with lattice vibrations which displays metallic, superconducting, and insulating phases. We solve the thermodynamics of this model and discuss its properties. The metal-insulator phase transition is second order for sc and bcc tight-binding bands. ...Band structure1970-08
54 DeTar, CarletonTwo-fireball phenomenon and the multiperipheral modelIn the context of the Chew-Snider version of the Amati-Bertocchi-Fubini-Stanghellini-Tonin pion-exchange model, we investigate certain multiperipheral mechanisms that could account for those phenomena that have hitherto motivated the two-fireball model. These mechanisms are (1) double diffractive ...Multiperipheral model; Fireballs1970-08
55 Mattis, Daniel C.Two-dimensional Ising model in a finite magnetic fieldWe present the results of numerical calculations giving accurate estimates of the magnetization of the two-dimensional Ising model on a square lattice. Moreover, we argue that these results are strict lower bounds to the correct magnetization M(H, T). The estimates are obtained by dividing the infin...Magnetization1970-10
56 Olivera, Baldomero M.Pyridine nucleotide metabolism in Escherichia coli. I. Exponential growthThe pyridine nucleotide pool of Escherichia coli is made up almost exclusively of DPN and TPN. In an exponentially growing glucose culture an average cell contains 1,460,000 molecules of DPN (30% reduced) and 440,000 molecules of TPN (57% reduced). If the total volume of the cell were accessible t...Nicotinic acid1971
57 Symko, Orest GeorgeContinuously operating 4He evaporation refrigeratorA simple and compact device was developed to provide continuous, self-regulating refrigeration at approximately 1.3 K. The temperature of the device remains nearly constant, independent of external power, up to a critical power. For a molar flow rate of 10^-4 moles/sec, the refrigerator can absorb...4He evaporation refrigerator1971
58 DeTar, CarletonMomentum spectrum of hadronic secondaries in the multiperipheral modelMotivated by a simplified multiperipheral model, we formulate a general qualitative description of the momentum spectrum of secondaries, resulting from a collision of two hadrons at high energies. Arguing from two fundamental multiperipheral concepts, (a) that transverse momenta are limited and (b...Secondaries; Multiperipheral model; Fireballs1971-01
59 Capecchi, Mario R.Polypetide chain termination. Purification of the release factors, R1 and R2, from Escherichia coli.We have extensively purified the release factors RI and Rz from Escherichia coli. These proteins can each mediate polypeptide chain termination. The physiological substrate for this reaction is a completed polypeptide chain in a peptidyl- transfer RNA-messenger RNA-ribosome complex. The reaction con...Acrylates; Detergents1971-02-25
60 Mattis, Daniel C.Critical curves and thermodynamic phases of lattice fluids and antiferromagnets with structured interactionsWe study the classical lattice gas with hard cores, nearest-neighbor repulsive forces, and next-nearest-neighbor attractive forces. We find several thermodynamic phases (vapor, liquid, and solid) and unusually shaped critical curves, yet no critical point or triple point. We find and discuss discont...Ising antiferromagnet; Molecular field theory1971-06
61 Mattis, Daniel C.Short-range versus long-range order in a model binary alloyWe calculate the free energy of a linear binary metallic alloy using an exact transfer-matrix formalism. We obtain for the first time the electronic band structure when there is nonvanishing short-range order and calculate the temperature dependence of the short-range order parameter. Following Foo...Binary alloys; Density of state; Free energy1971-07
62 Mattis, Daniel C.Exactly solvable model of a magnetic impurityA slight modification of the "mixing" term in Anderson's model of a magnetic impurity produces an exactly solvable model. Results of some preliminary calculations are given, and upper and lower bounds on Anderson's model are obtained by means of the exact solutions. .Magnetic impurity; Ground-state energy; Free energy1971-11
63 Ailion, David CharlesNew technique for determining the diffusion mechanism by NMR: application to Cl35 diffusion in TlClA major problem in the study of atomic motions is the determination of the dominant mechanism responsible for translational diffusion. Recently Ailion and Ho predicted that the rotating-frame spin-lattice relaxation time T l p would have an angular dependence which depends on the diffusion mechanis...Diffusion; Solids; NMR1972
64 Mattis, Daniel C.Exactly soluble model of interacting electronsWe diagonalize a many-fermion Hamiltonian consisting of terms quadratic as well as quartic in the field operators. A dual spectrum of eigenstates is an interesting result. We also derive a formula for obtaining the free energy at finite temperature.Eigenstates; Free energy; Excitation spectrum1972
65 Miller, Joel StevenInvolvement of titanocene and related species in the reduction of dinitrogen and olefinsSummary Four sequential products have been spectrally detected in the reduction by sodium of dicyclopentadienyltitanium(iv) dichloride: [(77-Cp)2TiCl]2, [(77-Cp)2-Ti]1-2, [(77-Cp)(C5H4)TiH]x, and (77-Cp)(C5H4)TiH2Ti- (C5H4)(77-Cp) ("stable titanocene"); the second of these reacts rapidly and rever...Hydrolysis; Sodium; Pressure1972
66 Gesteland, Raymond F.Pattern of protein synthesis in monkey cells infected by simian virus 40After infection of several permanent monkey cell lines by simian virus 40 (SV40), four additional protein bands can be detected by simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell extracts. These bands appear only after the onset of viral deoxyribonucleic acid (DNA) syn...Monkeys; Simian virus 40; Peptides; DNA, Viral/biosynthesis1972
67 Gesteland, Raymond F.Processing of adenovirus 2-induced proteinsAnalysis of (35)S-methionine-labeled extracts of adenovirus 2-infected KB cells revealed 22 virus-induced polypeptide components. Most proteins of the virion were easily detected in extracts of whole cells labeled for short periods between 15 and 30 h after infection; however, several virion compone...Adenoviridae; Viral Proteins; Protein Precursors; Methionine; Mouth Neoplasms1973
68 Olivera, Baldomero M.Pyridine nucleotide metabolism in Escherichia coli. IV. TurnoverThere are two pyridine nucleotide turnover pathways in Escherichia coli, the Gholson turnover cycle, with nicotinamide as an intermediate, and a second new pathway which does not involve nicotinamide. In exponentially growing cultures with a generation time of 60 min, the rates of these cycles are ...Turnover cycle; Adenine1973
69 Olivera, Baldomero M.Pyridine nucleotide metabolism in Escherichia coli. III. Biosynthesis from alternative precursors in vivoIn Escherichia coli, the nicotinamide moiety of pyridine nucleotides may be derived from de novo synthesis of the pyridine ring or through the uptake of either nicotinic acid or nicotinamide. De novo synthesis is the least preferred pathway; it is suppressed if an exogenous source is available. Nic...Nicotinic acid; Biosynthesis1973
70 Olivera, Baldomero M.Pyridine nucleotide metabolism in Escherichia coli. II. Niacin starvationThe effect of niacin starvation has been studied in a niacin-requiring auxotroph of Escherichia coli. If a culture is totally deprived of niacin, cells continue to divide until the total pyridine nucleotide content has fallen from 1.9 X 10^6 to 1.2 X 10^5 molecules per cell. During starvation, the r...Starvation; Nicotinic acid1973
71 Allen, Edgar S.Sensory information processing and symbolic computation (1 Jan. 1975 - 30 June 1975)This research uses digital computation to investigate processes, both linear and nonlinear, for the filtering. restoration, enhancement, bandwidth reduction, distortion immunization and analysis of both visual and auditory information.Sensory information processing; Symbolic computation; Auditory information; Visual information1973
72 Miller, Joel StevenIsomeric conformations in a pentaco-ordinated ruthenium compound: crystal and molecular structures of the orange and violet isomers of (Ph3P)2[(CF3)2C2S2]Ru(CO)Summary The molecular conformations of two square pyramidal species, one violet the other orange, both composition (Ph3P)2[(CF3)2C2S2]Ru(CO) are described.Pyramidal, Radiation,1973
73 Ailion, David CharlesProtein hydration changes in the formation of the nicotinamide adenine dinucleotide complexes of glyceraldehyde 3-phosphate dehydrogenase of yeast. II. The spin lattice relaxation of solvent water protonsThe glyceraldehyde 3-phosphate dehydrogenase of yeast is known to undergo a particle volume contraction and the commensurate loss of a hydration component when it forms a complex with NAD. We have inquired whether the water movement in the conformational transition can be monitored by measurements ...Protein hydration; Nicotinamide adenine dinucleotide complexes; Glyceraldehyde 3 phosphate dehydrogenase; Solvent water protons1973
74 Mattis, Daniel C.Second-order phase transition in a model random alloyWe investigate the existence and stability of long-range order in a simple model of a binary alloy. We find that for electron concentrations in the vicinity of one per atom, in bipartite lattices, long-range order of the atoms exists at low temperatures, and we find that the system undergoes a secon...Phase transition; Random alloys; Quasiparticles; Density of state1973-03
75 Mattis, Daniel C.Phonons and phase transitions of heliumWe find a new collective shear-wave-like mode above Tλ, merging with the longitudinal acoustic mode at a higher critical temperature. The speed of the new sound wave is predicted to vanish near Tλ as s ∞ (T -Tλ)½ .1973-06
51 - 75 of 1,952