bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy decay for the wave equation with boundary and localized dissipations in exterior domains
Authors: Bae Jeong Ja , Nakao Mitsuhiro
Published: April 2005

We study a decay property of solutions for the wave equation with a localized dissipation and a boundary dissipation in an exterior domain Ω with the boundary ∂Ω = Γ0 ∪ Γ1, Γ0 ∩ Γ1 = ∅︁. We impose the homogeneous Dirichlet condition on Γ0 and a dissipative Neumann condition on Γ1. Further, we assume that a localized dissipation a(x)ut is effective near infinity and in a neighborhood of a certain part of the boundary Γ0. Under these assumptions we derive an energy decay like E(t) ≤ C(1 + t)–1 and some related estimates. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shift operators contained in contractions and pseudocontinuable matrixvalued Schur functions
Authors: Boiko S. S. , Dubovoy V. K. , Fritzsche Bernd , Kirstein Bernd
Published: April 2005

We show that the pseudocontinuability of a matrix‐valued Schur function θ in the unit disk is completely determined by the properties of the maximal shift and maximal coshift contained in a corresponding contractive operator T which has the characteristic operator function θ.
A gaussian space of test functions
Authors: Jorgenson J. , Lang S.
Published: April 2005

Elsewhere we develop an aspect of analysis on the simplest space of type G/K when G = SL2(C) and K is the unitary subgroup, having to do with the analogue of Poisson's inversion formula and resulting additive zeta functions obtained by applying the Gauss transform. The present paper carries out systematically a number of foundational properties of gaussians on that space, which serve as test functions, give rise to explicit formulas, and lead immediately into the heat kernel, which is a gaussian. We prove approximation properties and the fact that the space of gaussians is dense in essentially anything space one wants. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Seiberg–Witten–Floer homology of a surface times a circle for non‐torsion spinℂ structures
Authors: Muñoz Vicente , Wang Bai‐Ling
Published: April 2005

We determine the Seiberg–Witten–Floer homology groups of the 3‐manifold Σ × 𝕊1, where Σ is a surface of genus g ≥ 2, together with its ring structure, for a Spinℂ structure with non‐vanishing first Chern class. We give applications to computing Seiberg–Witten invariants of 4‐manifolds which are connected sums along surfaces and also we reprove the higher type adjunction inequalities obtained by Oszváth and Szabó. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of left‐definiteness of Sturm–Liouville problems
Authors: Wei Guangsheng , Wu Jianhua
Published: April 2005

The left‐definiteness for both regular and singular Sturm–Liouville problems is characterized. We give a necessary and sufficient condition on the coefficients, the endpoints and the boundary conditions of Sturm–Liouville problems to determine the left‐definiteness. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Space‐time regularity of catalytic super‐Brownian motion
Authors: Zähle Henryk
Published: April 2005

We study the question for which catalysts does the catalytic super‐Brownian motion in R have a jointly continuous space‐time Lebesgue density. As it turns out, there is a large class of non‐atomic catalysts inducing a regular density. The latter can be characterized as the unique solution to a certain stochastic partial differential equation driven by an inhomogeneous space‐time white noise. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the global well‐posedness of discrete Boltzmann systems with chemical reaction
Authors: Oliveira Filipe , Soares A. J.
Published: April 2005

We study an initial‐boundary value problem in one‐space dimension for the discrete Boltzmann equation extended to a diatomic gas undergoing both elastic multiple collisions and chemical reactions. By integration of conservation equations, we prove a global existence result in the half‐space for small initial data N0∈ℬ︁∩L1. Copyright © 2005 John Wiley & Sons, Ltd.
Assessment of infant cry: Acoustic cry analysis and parental perception
Authors: LaGasse Linda L. , Neal A. Rebecca , Lester Barry M.
Published: April 2005

Infant crying signals distress to potential caretakers who can alleviate the aversive conditions that gave rise to the cry. The cry signal results from coordination among several brain regions that control respiration and vocal cord vibration from which the cry sounds are produced. Previous work has shown a relationship between acoustic characteristics of the cry and diagnoses related to neurological damage, SIDS, prematurity, medical conditions, and substance exposure during pregnancy. Thus, assessment of infant cry provides a window into the neurological and medical status of the infant. Assessment of infant cry is brief and noninvasive and requires recording equipment and a standardized stimulus to elicit a pain cry. The typical protocol involves 30 seconds of crying from a single application of the stimulus. The recorded cry is submitted to an automated computer analysis system that digitizes the cry and either presents a digital spectrogram of the cry or calculates measures of cry characteristics. The most common interpretation of cry measures is based on deviations from typical cry characteristics. Another approach evaluates the pattern across cry characteristics suggesting erarousal or underarousal or difficult temperament. Infants with abnormal cries should be referred for a full neurological evaluation. The second function of crying—to elicit caretaking—involves parent perception of the infant's needs. Typically, parents are sensitive to deviations in cry characteristics, but their perception can be altered by factors in themselves (e.g., depression) or in the context (e.g., culture). The potential for cry assessment is largely untapped. Infant crying and parental response is the first language of the new dyadic relationship. Deviations in the signal and/or misunderstanding the message can compromise infant care, parental effectiveness, and undermine the budding relationship. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:83–93.
Integral equation solution of heat extraction‐induced thermal stress in enhanced geothermal reservoirs
Authors: Ghassemi A. , Tarasovs S. , Cheng A. H.‐D.
Published: April 2005

During fluid injection in enhanced geothermal systems, thermo‐mechanical processes can play an important role. In fact, the phenomena of reservoir seismicity and the variation of injectivity with respect to injection water temperature can be attributed to the induced thermal stresses. In this paper, a three‐dimensional integral equation formulation is presented for calculating thermally induced stresses associated with the cooling of a fracture in a geothermal reservoir. By utilizing Green's function in the integral equation, the three‐dimensional heat flow and stresses in the reservoir are modelled without discretizing the reservoir. The formulation is implemented in a computer program for the solution of injection into an infinite fracture as well as for the injection/extraction in an arbitrarily shaped fracture. Copyright © 2005 John Wiley & Sons, Ltd.
Preparation of poly(propylene‐co‐γ‐butyrolactone carbonate) and release profiles of drug‐loaded microcapsules
Authors: Lu Lingbin , Huang Kelong
Published: April 2005

A new aliphatic poly(propylene‐co‐γ‐butyrolactone carbonate) (PPCG) was successfully synthesized through the copolymerization of carbon dioxide, propylene oxide (PO), and γ‐butyrolactone (GBL). GBL was inserted into the backbone of PO–CO2. The glass transition of PPCG was as high as 16 °C, far higher than that (−1.5 °C) of poly(propylene carbonate) (PPC). The decomposition temperatures of PPCG and PPC were only slightly different. Because of the existence of the GBL ester unit, PPCG had stronger degradability than PPC in a pH 7.4 phosphate‐buffered solution. However, when the PO/GBL ratio increased beyond 5:2, the excessive amount of GBL was not added to the polymerization. PPCG and PPC microcapsules were prepared by the water‐in‐oil‐in‐water multiple‐emulsion method. Glucose was encapsulated. The PPCG microcapsules, about 2 μm in diameter, had smooth and spherical surfaces. The glucose release test revealed that the glucose release speed of the PPCG–glucose microcapsules was more than eight times faster than that of the PPC–glucose microcapsules in a pH 7.4 phosphate‐buffered solution. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2468–2475, 2005
Circular dichroism induced by the helical conformations of acylated chitosan derivatives bearing cinnamate chromophores
Authors: Wu Yusong , Seo Toshihiro , Maeda Shiro , Sasaki Takashi , Irie Satoshi , Sakurai Kensuke
Published: April 2005

Through regioselective modifications, some acylated chitosan derivatives,O‐cinnamoyl chitosans with degree of substitution (DS) varying from 0.8 to 2.0 andN‐fatty acyl‐O‐dicinnamoyl chitosans with different fatty acyl chain lengths (C2–C12), were prepared, and their chiroptical properties in dilute solutions were investigated by circular dichroism (CD). Exciton coupling between two vicinal cinnamoyl chromophores appended to the helical mainchains gave rise to bisignate Cotton effects (CEs), which were used to deduce the absolute sense of the twisting structures in solution phase. It was found that the absolute helicities vary with DS, length of the fatty chain, and solvent property, but are nearly independent of thermal stimulus. The molecular interactions (hydrogen bonding and hydrophobic interaction) involved possibly in the self‐assembled ordered structures were discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1354–1364, 2005
Structure alignment via Delaunay tetrahedralization
Authors: Roach Jeffrey , Sharma Shantanu , Kapustina Maryna , Carter Charles W.
Published: April 2005

A novel protein structure alignment technique has been developed reducing much of the secondary and tertiary structure to a sequential representation greatly accelerating many structural computations, including alignment. Constructed from incidence relations in the Delaunay tetrahedralization, alignments of the sequential representation describe structural similarities that cannot be expressed with rigid‐body superposition and complement existing techniques minimizing root‐mean‐squared distance through superposition. Restricting to the largest substructure superimposable by a single rigid‐body transformation determines an alignment suitable for root‐mean‐squared distance comparisons and visualization. Restricted alignments of a test set of histones and histone‐like proteins determined superpositions nearly identical to those produced by the established structure alignment routines of DaliLite and ProSup. Alignment of three, increasingly complex proteins: ferredoxin, cytidine deaminase, and carbamoyl phosphate synthetase, to themselves, demonstrated previously identified regions of self‐similarity. All‐against‐all similarity index comparisons performed on a test set of 45 class I and class II aminoacyl‐tRNA synthetases closely reproduced the results of established distance matrix methods while requiring 1/16 the time. Principal component analysis of pairwise tetrahedral decomposition similarity of 2300 molecular dynamics snapshots of tryptophanyl‐tRNA synthetase revealed discrete microstates within the trajectory consistent with experimental results. The method produces results with sufficient efficiency for large‐scale multiple structure alignment and is well suited to genomic and evolutionary investigations where no geometric model of similarity is known a priori. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Characterization of oxygenated derivatives of isoprene related to 2‐methyltetrols in Amazonian aerosols using trimethylsilylation and gas chromatography/ion trap mass spectrometry
Authors: Wang Wu , Kourtchev Ivan , Graham Bim , Cafmeyer Jan , Maenhaut Willy , Claeys Magda
Published: April 2005

In the present study, we have tentatively identified the structures of three oxygenated derivatives of isoprene in Amazonian rain forest aerosols as the C5 alkene triols, 2‐methyl‐1,3,4‐trihydroxy‐1‐butene (cis and trans) and 3‐methyl‐2,3,4‐trihydroxy‐1‐butene. The formation of these oxygenated derivatives of isoprene can be explained by acid‐catalyzed ring opening of epoxydiol derivatives of isoprene, namely, 1,2‐epoxy‐2‐methyl‐3,4‐dihydroxybutane and 1,2‐dihydroxy‐2‐methyl‐3,4‐epoxybutane. The structural proposals of the C5 alkene triols were based on chemical derivatization reactions and detailed interpretation of electron and chemical ionization mass spectral data, including data obtained from first‐order mass spectra, deuterium labeling of the trimethylsilyl methyl groups, and MS2 ion trap experiments. The characterization of 2‐methyl‐1,3,4‐trihydroxy‐1‐butene (cis and trans) and 3‐methyl‐2,3,4‐trihydroxy‐1‐butene in forest aerosols is important from an atmospheric chemistry viewpoint in that these compounds hint at the formation of intermediate isomeric epoxydiol derivatives of isoprene and as such provide mechanistic insights into the formation of the previously reported 2‐methyltetrols through photooxidation of isoprene. Copyright © 2005 John Wiley & Sons, Ltd.
Paclitaxel induces apoptosis via caspase‐3 activation in human osteogenic sarcoma cells (U‐2 OS)
Authors: Lu K.‐H. , Lue K.‐H. , Chou M.‐C. , Chung J.‐G.
Published: April 2005

Paclitaxel has been found to exhibit cytotoxic and antitumor activity. There is little information regarding the mechanisms of apoptotic‐inducing effect of paclitaxel on human osteogenic sarcoma U‐2 OS cells. Several key regulatory proteins are involved in the initiation of apoptosis. Caspase‐3 plays a direct role in proteolytic cleavage of cellular proteins responsible for progression to apoptosis. We examined the effect of paclitaxel on the cell cycle arrest and apoptosis in U‐2 OS cells using flow cytometric analysis and Western blotting. We also measured the inhibition of paclitaxel‐induced apoptosis and the caspase‐3 activity by the broad‐spectrum caspase inhibitor z‐VAD‐fmk on U‐2 OS cells. The increased levels of casapse‐3 were also confirmed by cDNA microarray. Our observations were: (1) paclitaxel treatment resulted in G2/M‐cycle arrest in U‐2 OS cells; (2) time and dose dependent apoptosis of U‐2 OS cells was induced by paclitaxel; (3) in U‐2 OS cells, z‐VAD‐fmk blocked the paclitaxel‐induced apoptosis and caspase‐3 activation. These results suggest that paclitaxel‐induced G2/M‐cycle arrest of the G2/M phase and apoptosis via a caspase‐3 pathway in U‐2 OS cells. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
One‐ and two‐strand posterior cruciate ligament reconstructions: Cyclic fatigue testing
Authors: Shearn Jason T. , Grood Edward S. , Noyes Frank R. , Levy Martin S.
Published: April 2005

This study examined how one‐ and two‐strand posterior cruciate ligament (PCL) reconstructions resist the return of posterior translation during repetitive knee cycling. The femoral attachment of the one‐strand graft and the anterior strand of the two‐strand (AD2) grafts were located within the anterior one‐third of the femoral PCL footprint. The second strand was placed within the middle third of the femoral footprint in one of three locations: middle–distal (MD), middle–middle (MM), or middle–proximal (MP). During repetitive knee cycling from 5° to 120° flexion with a 100 N posterior force, the intact knee had less than 1 mm of residual posterior translation after 2048 flexion–extension cycles. Under similar cyclic conditions, the AD2‐MM reconstruction achieved the most cycles before failure; however, this two‐strand configuration failed in less than 700 cycles. The other reconstructions, either one strand or two strand, failed in less than 350 cycles. The surface failure location for 19 of 25 graft strands was within the femoral one‐third of the strand. We concluded that one‐ and two‐strand reconstructions under moderate loading and a range of motion from 5° to 120° flexion have an unacceptably high cyclic failure rate suggesting modifications of the allowable postoperative knee flexion and loading. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Providing artificial nest platforms for Cabot's tragopan Tragopan caboti (Aves: Galliformes): a useful conservation tool?
Authors: Deng Wen-hong , Zheng Guang-mei , Zhang Zheng-wang , Garson Peter J. , McGowan Philip J. K.
Published: April 2005

Cabot's tragopan Tragopan caboti, a pheasant that inhabits subtropical montane forests in south-east China, is categorized as Vulnerable on the IUCN Red List. Nesting in trees, it routinely makes use of natural platforms and the old nests of other species, both of which may sometimes be in short supply. This study was designed to test how much use would be made of artificial nest platforms, and to identify factors influencing their occupation. Basketry platforms made of bamboo were erected in parts of Wuyanling National Nature Reserve, Zhejiang Province, China. The tragopans used 16 platforms (8%) in 2002 and 12 (5%) in the following year. A census of the population in spring suggested that a high proportion of the females (41% in 2002, 36% in 2003) in the study area made use of the platforms. There were significant preferences for platforms in mixed conifer/broadleaf forest, as opposed to pure stands, as well as for sites on the upper part of hill slopes. Principal component scores were used to represent variation in 11 variables measured at each platform site. Binary logistic regressions employing these scores as predictors for each year separately did not reveal a consistent model for distinguishing used from unused platforms, although short distances to the forest edge were associated with use in both years. These nest platforms are cheap and easy to erect, and may have the potential to halt or reverse a perceived downward population trend for this species across the whole of its fragmented range. Further trials are therefore advocated.
Influence of fracture intersections under unsaturated, low‐flow conditions
Authors: Wood Thomas R. , Nicholl Michael J. , Glass Robert J.
Published: April 2005

Recent experimental evidence suggests that the capillary heterogeneity associated with fracture intersections can act to impose temporal and spatial structure on network‐scale flows. A simple intersection between orthogonal fractures, one horizontal and the other vertical, has been shown to integrate unsaturated flows. At low flows the intersection forms a capillary barrier that accumulates water in a growing pool. Eventually, the retaining meniscus snaps, discharging a pulse of water. Here we develop a mechanistic explanation for this observed behavior and experimentally consider three perturbations to the geometry of the simple orthogonal intersection. Two of the perturbations also act as capillary barriers, while the third formed a capillary bridge across the intersection. At low flow, all of our experimental intersections imposed a temporal signal, with the nature of that signal dependent on intersection geometry and participation by the horizontal fractures in dynamic storage. At high flow a continuous fluid tendril spanned the system from inlet to outlet with water pooled above the intersection caused by a narrow fluid connection that restricted flow across the intersection. Results from all experiments suggest that pulsation is critically sensitive to small variations in the geometry of fracture intersections and storage in the horizontal fractures. When combined with dependency on supply rate, this sensitivity can generate pulsation of flow across a wide range of time periods and discharge volumes.
Evidence of fine‐grained sediment transport and deposition in Sheboygan River, Wisconsin, based on sediment core chemical tracer profiles
Authors: Bzdusek Philip A. , Lu Jianhang , Christensen Erik R.
Published: April 2005

Fine‐grained sediment transport and deposition is observed in nine dated sediment cores obtained from the Sheboygan River. The sediment cores were dated by 137Cs and 210Pb methods. Sediment dating was supported by a polychlorinated biphenyl (PCB) analysis and U.S. Army Corps of Engineers (USACE) hydrographic surveys from 1976 to 2002. Plots of 137Cs activity versus depth show distinct peaks related to peak Sheboygan River discharges in the years 1966, 1975, 1979, and 1989. These peaks result from the scouring of sediments during storm discharges and the increased deposition of the fine‐grained fraction of particles, including colloidal clay particles (associated with 137Cs and, to some extent, PCBs), in place of the scoured sediments. Core SR1a, upstream of the Pennsylvania Avenue Bridge, and cores SR5‐SR8, farther downstream, show continuous sedimentation (1.2–11.8 cm/yr) since the late 1950s, whereas net sediment accumulation virtually ceased after 1988 at the intermediate sites of cores SR1–SR4. The maximum PCB concentration (161 ppm) occurs in 1969 in core SR4.
Bromination of Hydrocarbons. VII. Bromination of Isobutane. Bond Dissociation Energies from Bromination Kinetics
Authors: Eckstein Bernard H. , Scheraga Harold A. , Van Artsdalen Ervin R.
Published: April 2005

The kinetics of the gas phase photochemical bromination of isobutane to yield 2-bromo 2-methylpropane was investigated in the temperature range 40—95°C and the reaction found to proceed through an atom and radical chain mechanism analogous to that observed with a number of other hydrocarbons. The thermal reaction was studied at 112 and 130°C and shown to have the same mechanism except for the mode of production of bromine atoms. Bromination was inhibited by hydrogen bromide, a product of the reaction, and also by oxygen. The dissociation energy of the tertiary C–H bond in isobutane was found to be 89.6 kcal/mole at 0°K, in agreement with the idea that tertiary bonds are considerably weaker than primary bonds. A general review of activation energies of bimolecular reactions involved in bromination is given as well as a recapitulation of values of C–H and C–C bond dissociation energies derived from bromination studies.
Kinetics of the Reaction of Ethyl Bromomalonate with Thiosulfate
Authors: Broach Wilson J. , Amis Edward S.
Published: April 2005

The effect of changing the dielectric constant and the effect of changing the ionic strength on the reaction between thiosulfate ion and ethyl bromomalonate have been studied. The rates of the ion-molecule reaction could be accounted for on the basis of the simple second-order mechanism between the dipolar ester molecule and the thiosulfate ion represented by the equation C2H5OOCCHBrCOOC2H5+S2O3==C2H5OOCCH(S2O3)−COOC2H5+Br−and considering the change of ionic strength with extent of reaction to be secondary in importance.

The reactions of thiosulfate ion and ethyl bromomalonate was studied at 0.1°C and at 25°C. The specific reaction rates for this reaction conformed to the prediction of the Amis-Jaffe equations with respect to changing ionic strength and conformed to the Amis equation with respect to changing dielectric constant.
Raman Spectra of Chlorofluoromethanes in the Gaseous State
Authors: Claassen Howard H.
Published: April 2005

Raman spectra of gaseous CCl4, CCl3F, CCl2F2, CClF3, and CF4 are presented in the form of microphotometer traces. All but one of the fundamental frequencies of these molecules have been observed.
Irradiation of Ferrous Ammonium Sulfate Solutions: Energy Absorption and Ionization Calculations for Cobalt 60 and Betatron Radiation
Authors: Cormack D. V. , Hummel R. W. , Johns H. E. , Spinks J. W. T.
Published: April 2005

Solutions of ferrous ammonium sulfate in 0.8N H2SO4 have been irradiated with Co60 gamma rays and with x-rays from a 25-Mev betatron. The energy absorbed per unit volume of solution has been calculated from a modification of the Bragg-Gray formula, Ev=JvWρ in which the factor ρ was determined according to a calculated distribution of primary electron energies. The chemical yield was then calculated in terms of G, the number of ferrous ions oxidized per 100 ev absorbed.
A Proposal for Fundamental Equations of Dynamics of Gases under High Stress (A Proposal for Statistical Mechanical Treatment of Systems Not in Thermal Equilibrium Associated with Transport Phenomena)
Authors: Koga Toyoki
Published: April 2005

In order to derive the fundamental equations of gas dynamics which are valid for the flow at high shearing stress and low gas pressure, an attempt was made to eliminate the assumption that the state concerned departs only slightly from thermal equilibrium, as we frequently find phenomena which cannot be treated under this assumption.

First, the state of gas in an intermediate volume element was microscopically represented in terms of the quantities of transport. Considering their averages over an intermediate time interval, an attempt was made to find the statistical character of the system. In other words, under the assumption that the macroscopic observation is possible or that the macroscopic law can be established, it was shown that the Boltzmann-Planck method in a new sense is applicable to the present systems. The new distribution function thus derived, f=exp(α+Σβξcξ+ΣΣγξηcξcη+···) (where c denotes the velocity of a particle), should satisfy the Boltzmann-Maxwell equation. This can be shown by means of Kirkwood's verification accepted in some extended meaning.

In solving the B-M equation (hereafter, the B-M equation is the abbreviation of the Boltzmann-Maxwell equation) from this new standpoint, the stress components were taken together with mass density and velocity of mass motion as the independent variables in the zeroth approximation, although usually temperature is taken in place of stress. This method of treatment is analogous to that of Enskog and Chapman, although some important modifications are found in the latter half of the treatment. The fundamental equations of gas dynamics have been derived. Instead of viscosity and thermal conductivity, a new conception arises in the equations. That conception is conductivity of stress.
Lattice Dynamics of Body-Centered and Face-Centered Cubic Metallic Elements. II
Authors: de Launay Jules
Published: April 2005

A numerical table is presented which permits the easy calculation of the Debye characteristic temperature of any cubic metallic element at 0°K. The use of the table presupposes a knowledge of the elastic constants, atomic volume, and density of the element at 0°K. The characteristic temperature can be evaluated for either of the theoretical cases described in an earlier paper by the author.
Microwave Spectrum and Properties of Vinylene Carbonate
Authors: Slayton Geo R. , Simmons J. W. , Goldstein J. H.
Published: April 2005

The microwave spectrum of vinylene carbonate has been investigated in the region from 19 000 to 32 000 Mc/sec. Eight R-branch transitions have been identified and fitted with the following spectroscopic parameters: a = 9346.79 Mc/sec, b = 4188.46 Mc/sec, c = 2891.54 Mc/sec, all ±0.10 Mc/sec; k = —0.59818. The dipole moment of the vapor, as determined from Stark effect studies, is 4.51±0.05D and lies in the a-axis. The molecule has been shown to be planar. The significance of these results is discussed.
Electron Trap Distributions in Phosphors
Authors: Honig J. M.
Published: April 2005

The possible interpretation of long lifetime phosphorescence decay in terms of the electron trap mechanism is briefly reviewed. It is then shown how the distribution of activation energies among filled traps may be computed from the experimentally observed decay curves. The decay curves can be expressed as a Laplace transform of the distribution density function for activation energies, and the latter can then be calculated by inversion of the transform. Several examples are given in illustration of the procedure. The limitations inherent in the procedure are briefly discussed, and it is pointed out how the method might be used to test the applicability of the simple electron-trap model to experimental data.
Deviations from Additivity of the Intermolecular Field at High Densities
Authors: Jansen Laurens , Slawsky Zaka I.
Published: April 2005

The intermolecular field of an assembly of neutral atoms or molecules is usually assumed to be additive with respect to isolated pairs. Nonadditive effects have been calculated in the first-order forces by Rosen and in the second-order forces by Axilrod and Teller. For the evaluation of second-order forces between two molecules at high densities the zero-order wave function must be made antisymmetric with respect to nearest neighbors. It is shown that this correction results in a decrease of the second-order forces compared to an isolated pair of molecules, and may be interpreted as a screening effect. The method is based on the model of the caged atom or molecule.
Millimeter Wave Spectra and Centrifugal Stretching Constants of the Methyl Halides
Authors: Thomas W. J. Orville , Cox J. T. , Gordy Walter
Published: April 2005

High J transitions of the methyl halides have been measured and have been used to calculate accurate values for the centrifugal distortion constants.

The values obtained for BO, DJJ, and DJK are (in Mc/sec and kc/sec, respectively); CH3·F19, 25 536.11, 59.3, 445; CH3·Cl35, 13 292.86, 18.1, 198; CH3·Br79, 9568.20, 9.9, 128.3; CH3·Br81, 9531.82, 9.7, 127.4; CH3·I127, 7501.30, 6.28, 98.5.

The new DJJ value for CH3·Cl35 is in good agreement with the value of 18.4 kc/sec theoretically predicted by Chang and Dennison.

For all four molecules the DJJ constants were found to be in good agreement with those predicted from Kratzer's formula DJJ=4BO3/ω2,where ω is the vibrational frequency corresponding to the stretching of the carbon halogen bond.
Theory of the Interaction of Hindered Internal Rotation with Over-All Rotations. I. Symmetric Rotors: Methyl Silane
Authors: Kivelson Daniel
Published: April 2005

An approximate theory of the interactions of hindered internal rotation with over-all rotations of symmetric rotors is given. This treatment considers the interdependence of hindered internal rotation and vibrations and their effect upon the rotational energy levels. The resulting expression for the frequencies of ΔK = 0, ΔJ = 1 transitions is ν=2J[Bv+Fv(m|1−cos3θ|m)+Gv(m|Πz2|m)+LvK(m|Πz|m)],where Bv, Fv, Gv, and Lv are constants independent of the rotational quantum numbers, m represents the basis that diagonalizes the Hamiltonian corresponding to pure internal rotation, πz is the internal angular momentum operator, and θ is the angle of internal rotation. Procedures for evaluating (m|1—cos3θ|m) and (m|πzn|m) in terms of a parameter α are given.

This theory has been applied to the J=0→1 transitions of methyl silane. The parameters Bv, Fv, Gv, and α were obtained empirically and were then used to calculate frequencies. The agreement between observed and calculated values was quite good. Furthermore, the anomalous ordering of the lines observed by Lide and Coles1 is explained by these calculations. Assuming a cosine potential, the barrier height V0 is proportional to the parameter α. The value of V0 was set at 558 cm-1±17 cm-1. The constant Bv, which is the rotational constant in the ground torsional state for the limiting case of V0=0, is 10985.79 Mc/sec and 9636.50 Mc/sec for CH3SiH3 and CH3SiD3, respectively.
Elementary Processes in the Radiation Chemistry of Water
Authors: Laidler Keith J.
Published: April 2005

Schematic potential-energy diagrams are constructed for ground and excited states of H2O, H2O+ and H2O-, making use of thermochemical, spectroscopic, and electron-impact data. On electron impact a gaseous water molecule is raised to various states of H2O, H2O+ and H2O-, which may subsequently decompose to give H, O, H2, and OH and the ions H+, H-, O+, O-, OH+, and H2+. The exact mechanisms by which these atoms, radicals, and ions are produced are discussed in detail with reference to the potential-energy curves, due attention being paid to the appropriate correlation and selection rules. It is concluded that the production of O- at 173 kcal electron energy probably proceeds via a 2A1, 2B1, 2A2, or 2B2 state of H2O- which decomposes into 2H+O- without the prior formation of OH-. The production of O+ at 437 kcal must necessarily proceed via a 4A2 or 4B2 state of H2O+, while H2+ at 530 kcal must involve the formation of a 2A2 or 2B2 state; both these latter states are stable with respect to the simple breaking of an O—H bond. The nonappearance of OH- in electron-impact experiments is shown to be related to the high stability of OH-, states of H2O- which correlate with H+OH- being of very high energy. The bearing of the treatment on the radiation chemistry of liquid water is briefly considered.
The Relative Abundance of HT and HTO in the Atmosphere
Authors: Harteck P.
Published: April 2005

A kinetic discussion of the HT and HTO formation in the atmosphere indicates that the ratio of about 1 HT to 1000 HTO in nature and the very high T concentration of 4.10-15 in atmospheric hydrogen compared with about 3.10-18 in normal rain water can only be understood by means of a photochemical reaction. Since the tritium atoms are quickly removed by oxygen molecules in three-body collisions and form the TO2 radical which in turn forms HTO, the TO2 must be photochemically dissociated. The T atoms thus set free collide repeatedly with hydrogen atoms and undergo to a certain extent the exchange reaction H2+T=HT+H. On the other hand, the T atoms or TO2 radicals may react with ozone to form a OT radical which combines with the hydrogen of the atmosphere into HTO. In low altitudes the reaction of TO2 with air polluting bodies form HTO predominately. The ratio of these reactions is responsible for the ratio of HT and HTO in nature with the HTO brought down into the surface waters by rainfall.
Mass Spectrometric Study of the Evaporation Products of Strontium Oxide on Platinum
Authors: Bickel P. W. , Holroyd L. V.
Published: April 2005

The vapor above the SrO–Pt system was bombarded with electrons and the ion fragments analyzed by a mass spectrometer. Evaporator temperatures ranged from 1600°K to 1800°K. Log Sr+ vs 1/T plots were found to be time dependent initially. Eventually the plots became stable, and could be represented by two straight lines having a slope of 60 kcal/mole at the higher temperatures and of 138 kcal/mole at the lower temperatures. The appearance potential for Sr+ was approximately 5 volts. The ratio of Sr+ to SrO+ was between 10 and 100. These results indicate that thermal dissociation of SrO took place. An explanation based on a diffusion-limited mechanism is offered for the smaller slope of the upper part of the log Sr+ vs 1/T plot. The behavior of the SrO–Pt system is compared with that of the BaO–Pt system. The latter system does not appear to exhibit thermal dissociation.
Frequency Assignments for Normal Aliphatic Compounds: I. The Normal Paraffins in the Range 1450 cm—1 to 650 cm—1
Authors: Tschamler Hubert
Published: April 2005

It is assumed that the normal aliphatic hydrocarbons in their crystalline forms belong to the symmetry groups C2v (odd number of carbon atoms) or C2h (even number of carbon atoms), and that the selection rules for these symmetry groups hold exactly. It is then possible to work out a ``theoretical distribution pattern'' for the carbon-stretching modes, and for most types of the hydrogen deformation modes. Comparison of these patterns with available experimental data leads to a complete assignment of frequencies of these types in all the normal hydrocarbons for which data are available, and accounts satisfactorily for all spectral features for these materials in the solid and liquid state. The results might evidently be extended to other aliphatic series.
Potassium Bromide Disk Method for the Infrared Studies of Coördination Compounds
Authors: Lane Thomas J. , Sen D. N. , Quagliano J. V.
Published: April 2005

The infrared absorption of tetrakis(ethylenethiocarbamide)copper(I) nitrate, ethylenethiocarbamide, and potassium nitrate have been measured by the potassium bromide disk method. The assignment of the frequencies of ethylenethiocarbamide explains that part of the spectrum (the wavelength region between 7 and 13 microns) in which various CH2 deformation frequencies are expected to appear. Generally speaking the infrared spectrum of tetrakis(ethylenethiocarbamide)copper(I) nitrate can be regarded as the superposition of the spectra of ethylenethiocarbamide and potassium nitrate, except for the absorption peaks at 9.6 and 14 microns, which do not appear in the infrared spectra of ethylenethiocarbamide and potassium nitrate. It is interesting to note that these wavelengths correspond to the Raman frequencies (1050 cm—1 and 720 cm—1) of potassium nitrate, which should be infrared-inactive. The appearance of these frequencies in the absorption spectrum is explained by the distortion of the nitrate ion in tetrakis(ethylenethiocarbamide)copper(I) nitrate.
A Thermodynamic and Spectroscopic Study of Gaseous Magnesium Oxide
Authors: Brewer Leo , Porter Richard F.
Published: April 2005

Vapor pressure measurements on solid magnesium oxide show that the solid vaporizes mainly into molecular species. Spectroscopic experiments have been conducted and have shown that the known gaseous 1Σ electronic state of MgO is not the principal vaporizing species. A study of the ultraviolet bands, produced originally by magnesium burning in air, proves the lower electronic level of the molecule involved in this transition is more important than the 1Σ state of MgO. Within experimental uncertainty the heat of sublimation obtained from vapor pressure measurements agrees with a spectroscopically determined heat of sublimation of the molecule involved in the ultraviolet transition. The ultraviolet bands are shown to originate from a gaseous monomer of MgO. The vapor pressure of MgO at 2200°K is 3.8×10—4 atmos, and the vapor pressure over MgO reaches 1 atmos at 3040±60°K. The D0 value for MgO gas is 4.7 ev.
Hybridization and Ionic Character in CH3Cl
Authors: Schatz Paul N.
Published: April 2005

The quadrupole coupling constant and dipole moment of the CH3Cl molecule have been investigated as functions of the hybridization and ionic character. It is found that somewhat different results are obtained if one includes the effect of overlap in calculating the quadrupole coupling constant. The inclusion of overlap is contrary to the usual assumption that the quadrupole coupling constant arising from a purely covalent chlorine p bond is the same as the quadrupole coupling constant of a free chlorine atom. The results suggest that more s hybridization of the chlorine bonding wave function occurs than is assumed by Townes and Dailey and there is some indication of the occurrence of an appreciable amount of 3d character in this function. No precise assignment of values for the ionic character and hybridization appeared feasible.
Vibrational Spectrum and Structure of Nitryl Chloride
Authors: Ryason Raymond , Wilson M. Kent
Published: April 2005

An investigation of the infrared spectrum of gaseous NO2Cl and the Raman spectrum of liquid NO2Cl results in the following assignment of fundamental frequencies: ν1(a1)=1293 cm−1,ν2(a1)=794 cm−1,ν3(a1)=651 cm−1,ν4(b1)=1685 cm−1,ν5(b1)=367 cm−1,ν6(b2)=411 cm−1.The structural implications of the data are discussed, and it is concluded that the structure is Cl−N[open phi][open phi]OO· .However, it is not possible to say whether the molecule is planar or pyramidal.
Redetermination of the Crystal Structure of Lithium Sulfate Monohydrate Li2SO4·H2O
Authors: Larson Allen C. , Helmholz Lindsay
Published: April 2005

The crystal structure of lithium sulfate monohydrate has been reinvestigated in order to determine the position of the hydrogen bonds and to check on the asymmetry of the sulfate group in this substance suggested by the earlier work of Zeigler.

A disposition of the hydrogen bonds in agreement with the proton magnetic resonance results has been found and the sulfate group has the configuration of a regular tetrahedron within the limits of error of our measurements. Our results are in agreement with Zeigler in most essentials.
High-Speed Machine Computation of Ideal Gas Thermodynamic Functions. I. Isotopic Water Molecules
Authors: Friedman Abraham S. , Haar Lester
Published: April 2005

A procedure is developed for the machine computation of the partition functions for non-rigid rotating anharmonic oscillators. Vibrational-rotational coupling terms and low temperature rotational corrections are included. A general code has been designed to permit the calculation of the ideal gas thermodynamic functions for a large variety of molecular structures on the National Bureau of Standards Eastern Automatic Computer—SEAC. The method is illustrated by evaluating the thermodynamic functions for an asymmetric top molecule. Tables of Cp0/R, (H0–E00)/RT, (E00–F0)/RT, and S0/R have been evaluated for H2O, HDO, D2O, HTO, DTO, and T2O at close intervals from 50° to 5000°K. The time required for these computations is of the order of several minutes per molecule. The results for H2O are in good agreement with those obtained by direct summation.
Approximate Integral Evaluations Used in the Molecular Quantum Mechanics of Nonlinear Molecules
Authors: Barker Roland S. , Eyring Henry
Published: April 2005

Molecular energy calculations employing actual and approximate multicenter angular dependent integral evaluations are compared. Individual integral values for three-center integrals used in calculations for the triangular H3+ ion as computed by exact methods and by the approximate formulas of Mulliken and of Rudenberg are given. The results indicate that angular and distance relations of the nuclear skeleton of this polyatomic ion are determinable at almost the identical ``best'' value found using the much more laborious exact integral calculations. The energies of the approximate evaluations, however, indicate that once these ``best'' parametric values are determined the more exact calculations must be used. The approximate evaluations of second angular derivatives of integrals that are dependent on the angular and distance relations of component molecular nuclei are also computed and compared. Use of such derivatives in determination of approximate zero point energies, vibrational frequencies, and force constants is indicated.
Second Virial Coefficients of Gases Obeying a Modified Buckingham (Exp—Six) Potential
Authors: Rice William E. , Hirschfelder Joseph O.
Published: April 2005

The second virial coefficient has been calculated for gases obeying a modified Buckingham potential, (Exp-Six), [open phi](r)=ε1−6/α[6αeα(1−r/rm)−(rmr)6].The results are tabulated over the temperature range kT / ε from 0.40 to 400, and for seven values of the parameter α, from 12 to 15. The treatment was entirely classical, and no corrections for quantum effects were made.

A separate paper will present the evaluation of the parameters for specific substances and applications of the results, together with applications of the calculated transport properties given in the preceding paper.
The Vibrational Spectra and Structure of Solid Hydroxylamine and Deutero-Hydroxylamine
Authors: Nightingale R. E. , Wagner E. L.
Published: April 2005

The infrared spectra of thin films of H2NOH and D2NOD were obtained at — 78° and — 190°C in the region 4000—500 cm—1. Two distinct types of spectra resulted depending on whether the films were formed at — 78° or at — 190°C. The spectra obtained when the films were formed at — 190°C were characterized by broad overlapping bands; those formed at — 78°C gave much narrower bands, some of them splitting into two or more distinct components. The latter type spectrum is representative of the stable crystalline form at low temperature. This spectrum could not be correlated with the amine oxide form of hydroxylamine, NH3→O. Satisfactory vibrational assignments could, however, be made for the model with symmetry of the point group C3, H2NOH. If cis- and trans-rotational isomers coexist in the solid, they must possess very nearly the same potential energy or at least a high potential barrier between them. The O–H stretching vibration in the solid is found at a very low frequency, 2867 cm—1, indicating a very strong hydrogen-type bond with energy of about 13 kcal per mole.
Occurrence of Natural p — n Junctions in Lead Selenide
Authors: Goldberg Arthur E. , Mitchell George R.
Published: April 2005

Single crystals of PbSe were grown from melts in sealed quartz tubes. Except for a very narrow range of initial melt compositions, stoichiometric excesses of Pb or Se in the melt resulted in crystals that were wholly n or p type, respectively. Initial composition within the critical range yielded crystals showing both p and n regions.

The electrical resistivities were related to crystal compositions permitting the construction of the Pb-Se phase diagram in a narrow region about the compound PbSe. The invariant melting point for the system falls in the Se-rich region. This precludes the possibility of growing a crystal from a melt which is of stoichiometric composition throughout.
A Rectilinear Diameter Law of Mole Fractions for Binary Liquid-Vapor Coexistence Regions near the Critical Locus
Authors: Benson Sidney W. , Allen Peter E. M. , Copeland Charles S.
Published: April 2005

It has been found that in the neighborhood of the critical locus of many nonazeotropic binary, liquid-vapor systems at equilibrium, the sum of the mole fractions in the two phases of each of the two components (C,C′) may with reasonable precision be represented by the relationship Xv+Xl≡2−(Xv′+Xl′)=a logP/P0′;in which Xv and Xl are the mole fractions of the more volatile component (C) in vapor and liquid, respectively, which are in equilibrium at total pressure P at constant temperature, P0′ is the vapor pressure of the less volatile component C′, and a is a constant for each isotherm. Between the critical temperatures of the two components a shows greater temperature dependence as the lower critical temperature is approached.
The Origin of the Fluorescence in Self-Activated ZnS, CdS, and ZnO
Authors: Kröger F. A. , Vink H. J.
Published: April 2005

It is proposed that the luminescent center in ``self-activated'' ZnS consists of a cation vacancy whose nearest surroundings have lost one electron. Such a center is consistent with the fact that at low firing temperatures, the appearance of the blue fluorescence of self-activated ZnS depends upon the presence of ``promoter ions'' (monovalent anions or trivalent cations) whereas, if the firing temperature be sufficiently high, some blue fluorescence is obtained without the presence of such promoter ions. The luminescence of reduced ZnS, CdS, and ZnO is also discussed, and is attributed to anion vacancies that have trapped one electron.
Sodium Diffusion in Sodium Tungsten Bronze
Authors: Smith J. F. , Danielson G. C.
Published: April 2005

Diffusivity has been measured in single crystals of the metallic sodium tungsten bronze, Na0.78WO3, at 664°C, 752°C, and 832°C. Concentration gradients were established by effusion of sodium from single crystals into a vacuum and were measured by determining the variation in the lattice constant. The diffusivities were calculated by a method which is based upon Fick's first law and which, to the author's knowledge, has not been used previously. The data obtained from several crystals held at constant temperature for varying periods of time gave a family of curves showing the sodium concentration as a function of depth with time as a parameter. From these curves the mass of sodium transferred through a plane parallel to the surface and at any particular depth could be obtained; this mass was plotted as a function of time. The slope of this curve divided by the concentration gradient, both evaluated at the same time and depth, was taken as the diffusivity for the corresponding concentration. The diffusivity of sodium in Na0.78WO3 was found to be represented by the equation D=D0 exp (—ΔH/RT), where D0=0.87 cm2/sec and ΔH=51.8 kcal/mole. In order to calculate the diffusivity it was necessary to determine the coefficients of linear expansion. For Na0.8WO3 the length L at temperature Tc was found to be L=L0[1+(8.81×10−6)Tc−(1.92×10−9)Tc2],where L0 is the length at 0°C and Tc is the temperature in degrees centigrade.