bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemisorption und Widerstandsänderungen an aufgedampften Zirkoniumfilmen
Authors: Hansen N. 
Published: August 2023

AbstractAn im Höchstvakuum aufgedampften Zirkoniumfilmen wurde die Oberfläche gemessen und die Kinetik und die elektrischen Widerstandsänderungen bei der Adsorption von Kohlenmonoxid untersucht. Es treten verschiedene Chemisorptionsmechanismen auf, die sich in der Kinetik und der relativen Widerstandsänderung unterscheiden. Die Widerstandsänderungen lassen sich durch eine Verbindungsbildung mit einer bestimmten Zahl von Oberflächenatomen des Metalls und einer damit verbundenen Verringerung der effektiven Schichtdicke deuten.
Rotational and Translational Diffusion and Dipolar Spin Relaxation in Diamagnetic Electrolyte Solutions
Authors: Hertz H. C. 
Published: August 2023

AbstractThe present paper starts from the question to what an extent correlation times for the molecular rotation (or reorientation times) in the hydration shells may be derived from the nuclear magnetic relaxation times of the protons in diamagnetic electrolyte solutions.The intramolecular relaxation rate of the protons in aqueous electrolyte solutions is calculated. Use is made of a model in which the reorientation times in the hydration shells and the free water are different. Moreover, the various regions of the solution are characterized by different rotation‐step constants. The treatment is closely related to a work by Beckert and Pfeifer concerning the same subject. The results of the theorie are discussed with regard to the above mentioned question.Further, the calculation of the self‐diffusion coefficient of the water molecules in an electrolyte solution is described. The theory given is a random‐walk treatment, the procedure is similar to that presented for the rotational motion in the first part of this paper.In the last section the problem of the separation of the electrolyte solution in hydration shells and free water in its special concern to the rotational correlation times is dealt with.
A Microdynamic Model of Electrolyte Solutions as Derived from Nuclear Magnetic Relaxation and Self‐Diffusion Data
Authors: Endom L. , Hertz H. G. , Thül B. , Zeidler M. D. 
Published: August 2023

AbstractExperimental data of the proton relaxation rate in aqueous solutions of alkali and alkaline earth halides at four different temperatures (0, 25, 50, 80 °C) are reported. A number of measured self‐diffusion coefficients of water in electrolyte solutions at various temperatures are also given. From these experimental data models of the electrolyte solutions are derived which are characterized by certain hydration numbers, reorientational correlation times for the water molecules, translational jumping times, and by the activation energies connected with the respective microdynamic processes.
Die Strömungsmethode mit integrierender Anzeige zur Untersuchung schneller Reaktionen in Lösung unter Einbeziehung des Mischvorgangs
Authors: Gerischer H. , Heim W. 
Published: August 2023

AbstractEs wird für das Verfahren der Strömungsmethode mit integrierender Anzeige eine neue Meßzellenkonstruktion angegeben, mit welcher der Ablauf des Mischvorgangs zugleich mit der eigentlichen chemischen Reaktion erfaßt werden kann. Mit Hilfe der empirisch gefundenen Beziehung für die Zeitabhängigkeit des Mischprozesses können dann Reaktionen noch erfaßt werden, deren Abklingzeiten von gleicher Größenordnung sind wie die Abklingzeiten der Vermischung. Das sind bei den hier verwandten Meßzellen Zeiten in der Größenordnung von 10−5 sec. Mit diesem Verfahren wurde die Geschwindigkeitskonstante der Reaktion K4 [Fe(CN)6] + Fe(phen)3(ClO4)3 in 0,5 n Perchlorsäure gemessen. Es wurde an dieser Reaktion zugleich die Übereinstimmung der Resultate mit dem normalen integrierenden Verfahren überprüft.
Diffusionsüberspannung, Durchtrittsüberspannung und Doppelschichtaufladung beim galvanostatischen Einschaltvorgang
Authors: Bachmann K. J. 
Published: August 2023

AbstractAusgehend von einer Theorie von Berzins und Delahay [1] wird die Abhängigkeit der Konzentrationen der an der Durchtrittsreaktion magnified image beteiligten reduzierten und oxydierten Substanzen Sr, Sox vom Abstand x von der Elektrodenoberfläche und der Zeit t berechnet. Mit Hilfe der Funktionen cr (0, t), cox (0, t) kann eine Beziehung für die Zeitabhängigkeit der Diffusionsüberspannung ηd(t) hergeleitet werden. Eine Kombination dieser Beziehung mit der bereits von Berlins und Delahay angegebenen Gleichung für die Gesamtüberspannung η(t) ermöglicht die Berechnung der Zeitabhängigkeit der Durchtrittsüberspannung ηD(t). Die Aufladung der Doppelschicht wird dabei berücksichtigt. Der Anwendungsbereich dieser Theorie ist auf Systeme beschränkt, für die eine Aufteilung der konstant vorgegebenen Stromdichte i in einen kapazitiven Anteil ic zur Aufladung der Doppelschicht und einen Faradayschen Anteil iF sinnvoll ist (hinreichend kleine Austauschstromdichten i0 und Gleichgewichtskonzentrationen ocj, großer Fremdelektrolytüberschuß, kleine Zeiten t).
Raman‐ und Ultrarotspektren kristallisierter primärer aliphatischer Amine und ihrer N‐Deuteroderivate. Wasserstoff‐ und Deuteriumbrückenbindung kristallisierter primärer aliphatischer Amine
Authors: Wolff H. , Ludwig H. 
Published: August 2023

AbstractEs werden die Raman‐ und Ultrarotspektren von kristallisiertem Äthyl‐, n‐Propyl‐ und n‐Butylamin sowie ihren N‐Deuteroderivaten ermittelt und die von kristallisiertem Methylamin früher gewonnenen Ultrarotspektren im niederfrequenten Gebiet ergänzt. Die Spektren werden zugeordnet und auf das Verhalten von Wasserstoff‐ und Deuteriumbrückenbindung der Amine im Kristall untersucht.Aus dem Auftreten von zwei NH‐ und zwei ND‐Valenzbanden in den Spektren der halbdeuterierten Verbindungen ergibt sich, daß auch die Methylaminhomologen im Kristall zwei verschieden starke H‐ oder D‐Brücken aufweisen.Aus der Verschiebung der NH‐ oder ND‐Banden gegenüber der Lage bei den Monomeren folgt, daß die beiden Brücken von Propylamin ebenso wie die von Methylamin nur wenig in der Stärke voneinander abweichen, die beiden Äthyl‐ und Butylaminbrücken sich aber in der Stärke erheblich unterscheiden und dabei die eine der beiden ungleichen Brücken jeweils nur sehr schwach ist. Der größere Unterschied der Brücken bei gerader C‐Atom‐Anzahl der aliphatischen Kette wird darauf zurückgeführt, daß die Anordnung der Molekeln im Kristall eine etwas andere als bei ungerader C‐Atom‐Anzahl ist.Aus den Verschiebungen errechnen sich die Energien der beiden Deuteriumbrücken mit 2000 bzw. 4300 cal/mol jeweils um rund 300 cal/mol größer als die der beiden Wasserstoffbrücken.
Experimentelle Bestimmung der Keimgrößenverteilung einer belichteten photographischen Emulsion in Abhängigkeit von der Zahl der je Korn absorbierten Röntgenquanten
Authors: Simon F. J. 
Published: August 2023

AbstractEs wird eine Methode beschrieben, in welcher die Aufnahme von Fading‐Kurven die Größenverteilung der durch eine Rö‐Belichtung erzeugten latenten Bildkeime in einer Photoplatte quantitativ zu bestimmen gestattet. Es wird das Verhalten der Verteilungsparameter als Funktion der je Korn absorbierten Quanten quantitativ bestimmt. Hierbei zeigt sich, daß die Größenverteilung der Bildkeime einer lognormalen Verteilung genügt. Das zweite Moment der Verteilung nimmt diskontinuierlich ab mit zunehmender Zahl je Korn absorbierter Rö‐Quanten, während das erste Moment der 2/3‐Potenz der Zahl je Korn absorbierter Quanten direkt proportional ist, und der Proportionalitätsfaktor durch das Oxydationspotential bestimmt wird.
Translational and Anisotropic Rotational Diffusion in Liquid Chloroform as Studied by NMR Relaxation
Authors: Bender H. J. , Zeidler M. D. 
Published: August 2023

AbstractThe proton spin‐lattice relaxation rate of liquid chloroform was measured in the neat liquid and in CHCl3/CDCl3mixtures over the temperature range – 18° to 47°C. Translational self‐diffusion constants are reported in the same temperature range.The intramolecular proton rate obtained from the isotopic dilution measurements is split into a spin‐rotational part and a contribution from the proton‐chlorine dipolar interaction. The spin‐rotational rate is then evaluated by use of a formula which takes into account the anisotropic rotational diffusion of a symmetric‐top molecule. This equation is derived in a theoretical section. The results show that the diffusion equation provides the correct description for the rotational motion.The intermolecular dipolar proton‐proton relaxation rate obtained from the dilution experiments is used to check current theories. None of these describes the experimental results adequately. Various reasons for this failure are discussed.
Spin‐lattice Relaxation of 1,4‐Paradioxane in Different solvents
Authors: Czubryt J. , Tomchuk E. , Bock E. 
Published: August 2023

AbstractThe nuclear magnetic spin‐lattice relaxation time, T1, of 1,4‐paradioxane in deuterated 1,4‐paradioxane, deuterated chloroform, deuterated cyclohexane, deuterated benzene, and carbon tetrachloride was determined as a function of concentration and temperature over the temperature range of 10°C – 100°C. It was found that the rotational correlation time of the p‐dioxane molecule in infinitely dilute CDCl3 solution was significantly longer than in the other four solvents. In particular it was found that when the rotational correlation time of the p‐dioxane molecule measured at 20°C in CDCl3 solution was‐corrected for the difference in the viscosities of CDCl3 and p‐dioxane there resulted a corrected rotational correlation time of 17·10−12 s. This value is in fair agreement with the dielectric relaxation time of the CHCl3 molecule in infinitely dilute p‐dioxane solution reported by Antony and Smyth [1], viz. 16.5 · 10−12 sat 20°C. It was also found that the activation energy for molecular reorientation, ΔEτ of the p‐dioxane molecule in infinitely dilute CDCl3 was significantly higher than the activation energy for viscous flow, ΔEη in CHCl3, viz. 2.6 kcal/mol and 1.8 kcal/mol respectively. On the other hand it was found that in the case of the other four solvents ΔEτ, ≤ ΔEeta. It is suggested that the experimental results are best interpreted in terms of the formation of a complex between p‐dioxane and CDCl3 molecules which reorients as a single unit.
Internal Rotation of Nitroanilines in Liquids III. N‐n‐Alkyl‐2,4,6‐Trinitroanilines
Authors: Jouanne Jorn Von , Heidberg Joachim 
Published: August 2023

AbstractThe kinetic parameters of the internal rotation about the amino nitrogen‐ring carbon bond in N‐R‐2,4,6‐trinitroanilines with

in dichloromethane at temperatures between 25° and –80°C were determined by comparison of measured and calculated complete NMR line shapes. It was found that the height of the barrier to internal rotation is constant within the above class of compounds in concert with a previous model, and that the frequency of jumping over the barrier only slightly decreases with increasing chain length of the n‐alkyl substituents as estimated for n‐alkyl chains moving freely in the liquid.
Spin Relaxation in solutions of K3Mo(CN)8, K3W(CN)8 and K4Mo(CN)8
Authors: Poupko R. , Gilboa H. , Silver Brian L. , Loewenstein A. 
Published: August 2023

AbstractThe ESR linewidths in solutions of K3W(CN)8 and K3Mo(CN)8 were measured as a function of temperature and viscosity in various solvents. In addition the 14N NMR linewidths were measured in aqueous solutions of K4Mo(CN)8 as a function of the temperature. The results were interpreted using two approaches (a) The theory due to Kivelson and McClung [4], and (b) Attempting to obtain the best fit to a parametric equation in τC and τN, the correlation times for reorientation and angular momentum respectively. The model of Hubbard fails to account for the experimental results. The introduction of a temperature independent parameter κ, as suggested by Kivelson and coworkers, only partly improves the fit between experiment and theory. The correlation times, τc, derived from NMR measurements are in reasonable agreement with those obtained from ESR data.
Light Scattering by the Tight Binding of Molecular Reorientation to Collective Motions in Liquids
Authors: Ben‐Reuven A. , Gershon N. D. 
Published: August 2023

AbstractA molecular explanation is offered for the fine structure observed in the sharp component of the depolarized Rayleigh wings in the spectrum of light scattered by various organic liquids previously attributed by hydrodynamic theory to the coupling of reorientational motion to longitudinal and transverse sound waves. The present explanation is based on the suggestion that a collective motion, with a non‐uniform displacement velocity in space, will exert a torque on the molecules if their orientational state is tightly bound to the surrounding medium for most of the time. The strength of the fine structure features is expressed in terms of molecular quantities which, except for a simple geometrical factor, are independent of the character of the collective motion. The line shape pertaining to the coupling to longitudinal sound waves is reproduced with non‐arbitrarily adjusted parameters.
High‐Energy Neutron Scattering from Liquid He4
Authors: Sears V. F. 
Published: August 2023

AbstractIn the limit of large momentum transfer, κ, the cross section for the scattering of neutrons from a macroscopic system is given by the impulse approximation, in which the scattering atom recoils as if it were free, and the energy distribution of the scattered neutrons is the Doppler profile characteristic of the momentum distribution in the initial state. In particular, the zero‐momentum condensate in liquid He4 below the λ‐point will produce a sharp peak in the spectrum of the scattered neutrons at the position of the free‐particle recoil energy and the relative intensity of this peak equals the fraction of atoms in the condensate. For finite momentum transfers the condensate peak tends to be smeared out by final‐state interactions and it is estimated that values of κ ≳ 80 Å−1 are required for the appearance of a well‐defined condensate peak. Available neutron data in the range 4 ≲κ≲ 20 Å−1 show no condensate peak and the main features of the observed scattering can be understood in terms of a truncated expansion of the scattering function as a series of Hermite polynomials.
Vortex Motion in Fluids
Authors: Dymond J. H. , Alder B. J. 
Published: August 2023

AbstractMolecular dynamics studies on hard sphere systems have shown that the long positive tail found for the velocity autocorrelation function arises from vortex motion on a microscopic scale. Quantitative evidence for this correlated motion in real fluids at super‐critical densities is provided by an analysis of diffusion coefficient data.
Transport Processes Near the Critical Point of Gases and Binary Liquids in the Hydrodynamic Regime
Authors: Sengers J. V. 
Published: August 2023

AbstractA status report is presented on the anomalies observed in the behavior of transport properties near the critical point of gases and binary liquids. The shear viscosity exhibits a weak singularity near the critical point. An analysis is made of the experimental data for those transport properties, thermal conductivity and thermal diffusivity near the gas —liquid critical point and binary diffusion coefficient near the critical mixing point, that determine the critical slowing down of the thermodynamic fluctuations in the order parameter. The asymptotic behavior of the thermal conductivity appears to be closely related to the asymptotic behavior of the correlation length. The experimental data for the thermal conductivity and diffusivity are shown to be in substantial agreement with current theoretical predictions.
Supercritical Fluids as Mobile Phases in Chromatography
Authors: Bartmann D. 
Published: August 2023

AbstractCompressed fluids at temperatures in the critical range can be used as mobile phases in chromatography, especially for the separation of substances of low migration rate and/or low thermal stability. By variation of the pressure at supercritical temperatures the density of the mobile phase can be varied continuously from gas‐like to liquid‐like values, and the solvent power of the mobile phase and consequently the migration rate of the substances under test in the column can be increased by orders of magnitude (so‐called “Fluid Chromatography”). An experimental equipment for operating pressures up to 2000 atm is described. Results for a series of test substances (aliphatic and cyclic hydrocarbons) are presented. They illustrate the dependence of migration and resolution from the stationary phase and from the pressure and temperature of the mobile phase.
Photocatalytic Hydrodecarboxylation of Fatty Acids for Drop‐in Biofuels Production
Authors: de Araujo Jhudson G. L. , da Silva Maria do S. B. , Bento Júlia C. C. V. , de Azevêdo Amanda M. , de M. Araújo Aruzza M. , dos Anjos Aecia S. D. , Martínez‐Huitle Carlos A. , dos Santos Elisama V. , Gondim Amanda D. , Cavalcanti Lívia N. 
Published: August 2023

AbstractA mild, practical, and environmentally friendly method for the hydrodecarboxylation of fatty acids using an acridine‐based photoredox catalyst and thiophenol was developed. Cn‐1 alkanes were synthesized in good to excellent yields (up to 99 %) from C10−C18 saturated fatty acids under visible light irradiation (405 nm). The developed protocol was employed for a mixture of fatty acids obtained from the hydrolysis of Licuri oil, affording a mixture of C9−C17 hydrocarbons in quantitative yield, which demonstrates the potential application of the method to produce drop‐in biofuels.
Warm and cool reheated
Authors: Knoblauch Kenneth , Werner John S. , Webster Michael A. 
Published: August 2023

AbstractAmong more conventional perceptual attributes, such as hue brightness and saturation, color is universally assigned a value along a warm/cool dimension. The source of this aspect of color experience is uncertain and a subject of current debate in color science. An unpublished study from the late twentieth century has recently appeared in an online archive that makes publicly available the results of an extensive set of measurements that document the variation of warm/cool values throughout color space and shows that they relate simply to the sum of the red‐green and blue‐yellow opponent‐color activations (red+yellow vs. blue+green), which the authors suggest is consistent with a sensory basis for this distinction.
Theoretical Understanding on the Facilitated Photoisomerization of a Carbonyl Supported Borane System
Authors: Zhu Hong‐Yang , Li Quan‐Song 
Published: August 2023

AbstractBoron compound BOMes2 containing an internal B−O bond undergoes highly efficient photoisomerization, followed by sequential structural transformations, resulting in a rare eight‐membered B, O‐heterocycle (S. Wang, et al. Org. Lett. 2019, 21, 5285–5289). In this work, the detailed reaction mechanisms of such a unique carbonyl‐supported tetracoordinate boron system in the first excited singlet (S1) state and the ground (S0) state were investigated by using the complete active space self‐consistent field and its second‐order perturbation (MS‐CASPT2//CASSCF) method combined with time‐dependent density functional theory (TD‐DFT). Moreover, an imine‐substituted tetracoordinated organic boron system (BNMes2) was selected for comparative study to explore the intrinsic reasons for the difference in reactivity between the two types of compounds. Steric factor was found to influence the photoisomerization activity of BNMes2 and BOMes2. These results rationalize the experimental observations and can provide helpful insights into understanding the excited‐state dynamics of heteroatom‐doped tetracoordinate organoboron compounds, which facilitates the rational design of boron‐based materials with superior photoresponsive performances.
The relationship between green transformational leadership, corporate social responsibility, and task performance
Authors: Moin Muhammad Farrukh , Ikhide Juliet Eyore , Li Yi 
Published: August 2023

AbstractThis study investigates the mediating effect of corporate social responsibility (CSR) on the link between green transformational leadership (GTL) and task performance. We collected the time‐lagged data from employees in Chinese hospitality industry. Further, we used regression analysis for testing. We found that GTL has a direct relationship with task performance. Also CSR mediates the positive link between GTL and performance. We highlighted the key relationship of CSR concept in linking GTL with workers task performance in hotel industry. Our study showed that supervisor leadership style can help the firm to engage in sustainability practices which enable workers to improve their performance. Literature on CSR calls for more research to explore about the causes and consequences of it. Responding to those calls, we proposed and tested a model wherein GTL links with CSR and thus affects workers performance. Implications and future research directions are discussed.
Administration study of recombinant erythropoietin on the carriers of variant c.577del in EPO gene
Authors: He Sen , Liu Xinchao , Song Huifang , Zhou Xinmiao 
Published: August 2023

AbstractThe issue of misjudgment in recombinant erythropoietin (rEPO) detection caused by the variant c.577del in human EPO gene has been found in recent years. Though the method of analyzing de‐N‐glycosylated erythropoietins (EPO) in blood samples was developed for identifying both EPO_p.Arg193AspfsTer28 (VAR‐EPO) and rEPO, it cannot be applied without the evaluation of excreted samples. For this purpose, five heterozygous carriers of the variant c.577del were recruited in an administration study of rEPO. Urine and blood samples were collected at different times before and after subcutaneous injection with a single‐dose of 50 IU/kg. The urine samples were analyzed for intact EPO, while the serum samples were analyzed for both intact and de‐N‐glycosylated EPO. A typical mixed band was detected in all blank and wash‐out urine samples, which all displayed a similar result with rEPO abuse. For the analysis of intact EPO in serum samples, a typical mixed band was detected in the wash‐out samples from day 1 to day 3, which could be identified as rEPO directly, while double‐band was observed in other samples with inconclusive results. The result of de‐N‐glycosylated EPO in all serum samples showed two separated bands, and the ratioL/U decreased along with wash‐out periods. Also, compared with the intact EPO analysis, a longer detection window without false positive results was obtained when analyzing de‐N‐glycosylated EPO. Analysis of de‐N‐glycosylated EPO is not only able to recognize the variant carriers directly but also able to detect rEPO abuse in the blood samples from the variant carriers with higher efficiency than the analysis of intact EPO.