bluuebunny/crossref_metadata_2025 huggingface dataset:
Radyo frekans kestırme sonuçlarinin coğrafı bılgı sıstemlerı tabanli yazilim ve görüntüleme sıstemı ıle desteklenmesı
Authors: TEMİZEL Bora , GÖSE Ersin , AYDEMİR M.Emre
Published: March 2014

Finding the position of signal sources has been effectively used by military systems including targeting, positioning, orbiting primarily, as well as in civil applications such as detecting mine sources, observing the natural environment. Direction finding that explored the importance during the World War II, has been widely used at the present time while there has been considerable improvement. While systems could detect only one source at early times, they can be capable of detecting two or more signals at the same time today, with the exploring of subspace techniques.

In this study, we first give some information about direction finding systems then with these information, develop a study on evaluating a new space segment supported alternately methoded prototype hardware and software to cover the gap that direction finding systems have because of uncontrollable mistakes.

The aim of this study, to support the hardware which planned to be produced on these purpose with an factual software and by the way, based on the prototype measurements before the mass production to take out criterion for the final products.
Hava ulaştirma görevlerinin başariminin tahmini
Authors: CİN Deniz , IŞIK Okay
Published: March 2014

Özet

Ulaştırma filolarının temel görevi, planlanan noktalara uçarak personel ve malzemeyi bu noktaların birinden diğerine taşımaktır. Günlük olarak planlanan her bir görevin yerine getirilebilmesi için uçuşa hazır uçuş ekibine ve uçağa ihtiyaç vardır.

Bu çalışmanın amacı, tasarlanan model dâhilinde belirlenen etmenlerin uçuş görevlerini nasıl etkilediğini belirlemek ve günlük uçulabilecek görev sayısının tahmininde kullanılabilecek bir tahmin modeli elde ederek planlamaların daha sağlıklı yapılabilmesine yardımcı olmaktır.

Bu çalışmada, benzetim modeli ARENA yazılımında tasarlanmış, NOLH (Dikeye Yakın Latin Hiperküp) deney tasarımı ile belirlenen girdiler ile elde edilen çıktı değerleri Design-Expert yazılımına aktarılmıştır.

Etmenlerin uçuş görevlerine etkileri Design-Expert yazılımı ile çözümlenmiş, tahmin modeli Yanıt Yüzeyi kullanılarak elde edilmiştir.
Faulting within the Pacific plate at the Mariana Trench: Implications for plate interface coupling and subduction of hydrous minerals
Authors: Emry Erica L. , Wiens Douglas A. , Garcia‐Castellanos Daniel
Published: March 2014

We investigate faulting within the incoming Pacific plate at the Mariana subduction trench to understand stresses within the bending plate, regional stresses acting upon the plate interface, and the extent of possible faulting‐induced mantle serpentinization. We determine accurate depths by inverting teleseismic P and SH waveforms for earthquakes occurring during 1990–2011 with Global Centroid Moment Tensor (GCMT) solutions. For earthquakes with Mw 5.0+, we determine centroid depths and source time functions and refine the fault parameters. Results from Central Mariana indicate that all earthquakes are extensional and occur at centroid depths down to 11 km below the Moho. At the Southern Mariana Trench, extensional earthquakes continue to 5 km below the Moho. One compressional earthquake at 34 km below the seafloor suggests stronger plate interface coupling here. In addition, we model the stress distribution within the Pacific plate along two bathymetric profiles extending seaward from the Mariana subduction trench axis to better understand whether our earthquake depth solutions match modeled scenarios for plate bending under applied external forces. Results from our flexure models match the locations of extensional and compressional earthquakes and suggest that the Pacific plate at Southern Mariana is experiencing larger, compressional stresses, possibly due to greater interplate coupling. Additionally, we conclude that if extensional faulting promotes the infiltration of water into the subducting plate mantle, then the top 5–15 km of the Pacific plate mantle are partially serpentinized, and a higher percentage of serpentinization is located near the Central Mariana trench where extensional events extend deeper.
A method to represent subgrid‐scale updraft velocity in kilometer‐scale models: Implication for aerosol activation
Authors: Malavelle Florent F. , Haywood Jim M. , Field Paul R. , Hill Adrian A. , Abel Steven J. , Lock Adrian P. , Shipway Ben J. , McBeath Kirsty
Published: March 2014

Updraft velocities strongly control the activation of aerosol particles or that component that act as cloud condensation nuclei (CCN). For kilometer‐scale models, vertical motions are partially resolved but the subgrid‐scale (SGS) contribution needs to be parametrized or constrained to properly represent the activation of CCNs. This study presents a method to estimate the missing SGS (or unresolved) contribution to vertical velocity variability in models with horizontal grid sizes up to ∼2 km. A framework based on Large Eddy Simulations (LES) and high‐resolution aircraft observations of stratocumulus and shallow cumulus clouds has been developed and applied to output from the United Kingdom Met Office Unified Model (UM) operating at kilometer‐scale resolutions in numerical weather prediction configuration. For a stratocumulus deck simulation, we show that the UM 1 km model underestimates significantly the variability of updraft velocity with an averaged cloud base standard deviation between 0.04 and 0.05 m s−1 compared to LES and aircraft estimates of 0.38 and 0.54 m s−1, respectively. Once the SGS variability is considered, the UM corrected averages are between 0.34 and 0.44 m s−1. Off‐line calculations of CCN‐activated fraction using an activation scheme have been performed to illustrate the implication of including the SGS vertical velocity. It suggests increased CCN‐activated fraction from 0.52 to 0.89 (respectively, 0.10 to 0.54) for a clean (respectively, polluted) aerosol environment for simulations with a 1 km horizontal grid size. Our results highlight the importance of representing the SGS vertical velocity in kilometer‐scale simulations of aerosol‐cloud interactions.
The signal of aerosol‐induced changes in sunshine duration records: A review of the evidence
Authors: Sanchez‐Romero A. , Sanchez‐Lorenzo A. , Calbó J. , González J. A. , Azorin‐Molina C.
Published: March 2014

Aerosols play a significant yet complex and central role in the Earth's radiation budget, and knowledge of long‐term changes in the atmospheric turbidity induced by aerosols is therefore fundamental for a better understanding of climate change. However, there is little available information on changes in aerosol concentration in the atmosphere, especially prior to the 1980s. The present paper reviews publications reporting the suitability of sunshine duration records with regard to detecting changes in atmospheric aerosols. Some of the studies reviewed propose methods for estimating aerosol‐related magnitudes, such as turbidity, from sunshine deficit at approximately sunrise and sunset, when the impact of aerosols on the solar beam is more easily observed. In addition, there is abundant evidence that one cause of the decadal changes observed in sunshine duration records involves variations in atmospheric aerosol loading. Possible directions for future research are also suggested: in particular, detailed studies of the burn (not only its length but also its width) registered by means of Campbell‐Stokes sunshine recorders may provide a way of creating time series of atmospheric aerosol loading metrics dating back to over 120 years from the present.
Some recent advances in learning and adaptation for uncertain feedback control systems
Authors: Xu Xin , Wang Cong , Lewis Frank L.
Published: March 2014

Learning and adaptation are essential abilities for feedback control systems to improve performance under uncertainties and external disturbances. In the past decades, there are more and more research interests in developing feedback controllers with learning abilities to ensure stability or optimality of closed‒loop systems. In this guest editorial for the special issue, some recent advances in this area are introduced from three perspectives. The first one is about new developments in adaptive dynamic programming and reinforcement learning methods, which use function approximators such as neural networks to approximately solve the adaptive optimal control problem of uncertain nonlinear systems. The second perspective is related to the learning issues in adaptive control systems based on neural networks. The third perspective includes some new results to deal with uncertainties in feedback control systems based on traditional nonlinear control approaches such as multi‒step nonlinear model predictive control and nonlinear H‒∞ control.
Enhancing Field‐Effect Mobility of Conjugated Polymers Through Rational Design of Branched Side Chains
Authors: Fu Boyi , Baltazar Jose , Sankar Ashwin Ravi , Chu Ping‐Hsun , Zhang Siyuan , Collard David M. , Reichmanis Elsa
Published: March 2014

The design of polymer semiconductors possessing effective π–π intermolecular interactions coupled with good solution processability remains a challenge. Structure‐property relationships associated with side chain structure, π–π intermolecular interactions, polymer solubility, and charge carrier transport are reported for a donor–acceptor(1)‐donor–acceptor(2) polymer: 5‐Decylheptadecyl (5‐DH), 2‐tetradecyl (2‐DT), and linear n‐octadecyl (OD) chains are substituted onto a polymer backbone consisting of terthiophene units (T) between two different electron acceptors, benzothiadiazole (B), and diketopyrrolopyrrole (D), pTBTD, to afford pTBTD‐5DH, pTBTD‐2DT, and pTBTD‐OD, respectively. In the 5‐DH side chain, the branching position is remote from the polymer backbone, whereas it is proximal in 2‐DT. This study demonstrates that incorporation of branched side chains where the branching position is remote from the polymer backbone merges the advantages of improved solubility from branched units with effective π–π intermolecular interactions normally associated with linear chains on conjugated polymers. pTBTD‐5DH exhibits superior qualities with respect to the degree of polymerization, solution processability, π–π interchain stacking, and charge carrier transport relative to the other analogs. pTBTD‐5DH exhibits a field‐effect hole mobility of up to 2.95 cm2 V–1 s–1, a factor of 3–7 times that achieved with pBDT6‐DT and pBDT6‐OD.
Hyperintense cortical signal on magnetic resonance imaging reflects focal leukocortical encephalitis and seizure risk in progressive multifocal leukoencephalopathy
Authors: Khoury Michael N. , Alsop David C. , Agnihotri Shruti P. , Pfannl Rolf , Wuthrich Christian , Ho Mai‐Lan , Hackney David , Ngo Long , Anderson Matthew P. , Koralnik Igor J.
Published: March 2014

Objective

To determine the frequency of hyperintense cortical signal (HCS) on T1‐weighted precontrast magnetic resonance (MR) images in progressive multifocal leukoencephalopathy (PML) patients, its association with seizure risk and immune reconstitution inflammatory syndrome (IRIS), and its pathologic correlate.

Methods

We reviewed clinical data including seizure history, presence of IRIS, and MR imaging scans from PML patients evaluated at our institution between 2003 and 2012. Cases that were diagnosed either using cerebrospinal fluid JC virus (JCV) polymerase chain reaction, brain biopsy, or autopsy, and who had MR images available were included in the analysis (n = 49). We characterized pathologic findings in areas of the brain that displayed HCS in 2 patients and compared them with isointense cortex in the same individuals.

Results

Of 49 patients, 17 (34.7%) had seizures and 30 (61.2%) had HCS adjacent to subcortical PML lesions on MR images. Of the 17 PML patients with seizures, 15 (88.2%) had HCS compared with 15 of 32 (46.9%) patients without seizures (p = 0.006). HCS was associated with seizure development with a relative risk of 4.75 (95% confidence interval = 1.2–18.5, p = 0.006). Of the 20 patients with IRIS, 16 (80.0%) had HCS compared with 14 of 29 (49.3%) patients without IRIS (p = 0.04). On histological examination, HCS areas were associated with striking JCV‐associated demyelination of cortical and subcortical U fibers, significant macrophage infiltration, and a pronounced reactive gliosis in the deep cortical layers.

Interpretation

Seizures are a frequent complication in PML. HCS is associated with seizures and IRIS, and correlates histologically with JCV focal leukocortical encephalitis. Ann Neurol 2014;75:659–669
Homocysteine exacerbates β‐amyloid pathology, tau pathology, and cognitive deficit in a mouse model of Alzheimer disease with plaques and tangles
Authors: Li Jian‐Guo , Chu Jin , Barrero Carlos , Merali Salim , Praticò Domenico
Published: March 2014

Objective

High level of homocysteine (Hcy) is a recognized risk factor for developing Alzheimer disease (AD). However, the mechanisms involved are unknown. Previously, it was shown that high Hcy increases brain β‐amyloid (Aβ) levels in amyloid precursor protein transgenic mice, but no data are available on the effect that it may have on the other main pathologic features of AD such as tau.

Methods

3xTg mice with diet‐induced high Hcy were compared with mice having normal Hcy. Neuronal cells were incubated with and without Hcy.

Results

Diet‐induced high Hcy resulted in an exacerbation of the entire AD‐like phenotype of the 3xTg mice. In particular, we found that compared with controls, mice with high Hcy developed significant memory and learning deficits, and had elevated Aβ levels and deposition, which was mediated by an activation of the γ‐secretase pathway. In addition, the same mice had a significant increase in the insoluble fraction of tau and its phosphorylation at specific epitopes, which was mediated by the cdk5 pathway. In vitro studies confirmed these observations and provided evidence that the effects of Hcy on Aβ and tau are independent from each other.

Interpretation

Taken together, our findings demonstrate that a dietary condition that leads to an elevation of Hcy levels results in an exacerbation of all 3 major pathological features of the AD phenotype: memory deficits, and Aβ and tau neuropathology. They support the concept that this dietary lifestyle can act as a risk factor and actively contribute to the development of the disease. Ann Neurol 2014;75:851–863
Streptococcus pneumoniae worsens cerebral ischemia via interleukin 1 and platelet glycoprotein Ibα
Authors: Dénes Ádám , Pradillo Jesus M. , Drake Caroline , Sharp Andrew , Warn Peter , Murray Katie N. , Rohit Bazaz , Dockrell David H. , Chamberlain Janet , Casbolt Helen , Francis Sheila , Martinecz Bernadett , Nieswandt Bernhard , Rothwell Nancy J. , Allan Stuart M.
Published: March 2014

Objective

Bacterial infection contributes to diverse noninfectious diseases and worsens outcome after stroke. Streptococcus pneumoniae, the most common infection in patients at risk of stroke, is a major cause of prolonged hospitalization and death of stroke patients, but how infection impacts clinical outcome is not known.

Methods

We induced sustained pulmonary infection by a human S. pneumoniae isolate in naive and comorbid rodents to investigate the effect of infection on vascular and inflammatory responses prior to and after cerebral ischemia.

Results

S. pneumoniae infection triggered atherogenesis, led to systemic induction of interleukin (IL) 1, and profoundly exacerbated (50–90%) ischemic brain injury in rats and mice, a response that was more severe in combination with old age and atherosclerosis. Systemic blockade of IL‐1 with IL‐1 receptor antagonist (IL‐1Ra) fully reversed infection‐induced exacerbation of brain injury and functional impairment caused by cerebral ischemia. We show that infection‐induced systemic inflammation mediates its effects via increasing platelet activation and microvascular coagulation in the brain after cerebral ischemia, as confirmed by reduced brain injury in response to blockade of platelet glycoprotein (GP) Ibα. IL‐1 and platelet‐mediated signals converge on microglia, as both IL‐1Ra and GPIbα blockade reversed the production of IL‐1α by microglia in response to cerebral ischemia in infected animals.

Interpretation

S. pneumoniae infection augments atherosclerosis and exacerbates ischemic brain injury via IL‐1 and platelet‐mediated systemic inflammation. These mechanisms may contribute to diverse cardio‐ and cerebrovascular pathologies in humans. Ann Neurol 2014;75:670–683
Plasticization effect of hydrogenated transgenic soybean oil on nitrile‐butadiene rubber
Authors: Wang Zhao , Han Yue , Huang Zhaohui , Zhang Xing , Zhang Liqun , Lu Yonglai , Tan Tianwei
Published: March 2014

Nitrile‐butadiene rubber (NBR) compounds were prepared with different amounts of hydrogenated transgenic soybean oil (HTSO) as renewable plasticizers. For comparison, similar compounds were prepared with petroleum‐based dioctyl‐phthalate (DOP), one of the most common plasticizers for NBR. Four HTSOs with different degree of hydrogenation were used, of which three HTSOs are prepared by hydrogenation reaction at different reaction conditions and one is commercial available. The plasticization effects of HTSO and of DOP were studied by Mooney viscometry, capillary rheometry, differential scanning calorimetry (DSC), and rubber processing analysis (RPA). The results showed that all the HTSOs had better plasticization effect than DOP on NBR. The swelling index result showed that the highly‐hydrogenated‐HTSO plasticized NBR vulcanizate have higher crosslinking density than the low‐hydrogenated ones. It is worthy to mention that, the introduction of high‐hydrogenated‐HTSO greatly improved both the processability of the NBR compounds and the mechanical performance of the final products, which is hard to achieve for most of the plasticizers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40643.
Application of cubic equation of state models in prediction of vapor–liquid equilibria for binary polyvinyl acetate/solvent solutions
Authors: Ahmadloo Ebrahim , Sobhanifar Najmeh
Published: March 2014

The cubic equation of state (CEoS) is a powerful method for calculation of (vapor + liquid) equilibrium (VLE) in polymer solutions. Using CEoS for both the vapor and liquid phases allows one to calculate the non‐ideality of polymer solutions based on a single EoS approach. In this research, vapor–liquid equilibria calculations of polyvinyl acetate (PVAc)/solvent solutions were performed. In this approach, eight models containing PRSV and SRK CEoS separately combined with four mixing rules namely vdW1, vdW2, Wong–Sandler (WS), and Zhong–Masuoka (ZM) were applied to calculations of bubble point pressure. For the better prediction, the adjustable binary interaction parameters existing in any mixing rule were optimized. The results were very acceptable and satisfactory. Absolute average deviations (%AAD) between predicted results and experimental bubble point pressure data were calculated and presented. The capability of two cubic equations of state had a good agreement with experimental data and predict the correct type of phase behavior in all cases, but the performance of the PRSV + vdW2 was more reliable than the other models with 2.65% in AAD for total of solution systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40651.
Orange peel‐derived pectin jelly and corn starch‐based biocomposite film with layered silicates
Authors: Çokaygil Zerrin , Banar Müfide , Seyhan A. Tuğrul
Published: March 2014

Orange peel‐derived pectin jelly/corn starch‐based biocomposite films with and without layered silicates (LSs) were prepared using melt extrusion followed by film die casting. To enhance interfacial compatibility, corn starch and LSs were chemically modified. Regardless of chemical modification or LS weight content, different pectin jelly‐to‐starch weight ratios (63/37, 60/40, 57/43, and 54/46) were considered to formulate the ingredients of biocomposite films in light of Taguchi‐based predictions. X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), scanned electron microscopy (SEM) and transmission electron microscopy (TEM) were systematically used to characterize corn starch, LSs, and biocomposite films. Among all the films considered, pectin jelly/modified (15%) starch‐based biocomposite film (54/46 w/w) containing 0.25 wt % of pristine LSs was found to be the most promising in terms of texture structure and mechanical integrity. Furthermore, creep recovery, hydrophobicity, and water vapor and oxygen gas transmission rates of the most promising biocomposite film were experimentally determined. Based on the findings obtained, the overall performance of the biocomposite film was evaluated and weighed against the overall performance of a low‐density polyethylene film. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40654.
Direkte Bestimmung der Druckabhängigkeit der Thermospannung flüssigen Quecksilbers
Authors: Schmutzler R. , Hensel F.
Published: March 2014

Messungen der absoluten Thermospannung des flüssigen Quecksilbers bei Drucken bis zu 1000 bar und bei Temperaturen zwischen 20°C und 120°C wurden ausgeführt. Zur genauen Ermittlung der relativ kleinen Druckkoeffizienten der Thermospannung [(∂S/∂p)T = 1.98 · 10−4 V/°K bar bei 20°C und (∂S/∂p)T) = 2,78 · 10−4 V/°K bar bei 100°C] wurde die Spannung eines Thermoelements gemessen, dessen beide Schenkel aus flüssigem Quecksilber bestehen, wobei nur der Druck in den beiden Schenkeln um einen kleinen Betrag Δp verschieden ist. Diese neu entwickelte Meßmethode kann auch zur Untersuchung anderer Metalle benutzt werden.
Untersuchungen zur Fehlordnung des γ‐CuJ
Authors: Herzog G. W. , Krischner H. , Wabl M. R.
Published: March 2014

Die Bildungsenergie für Schottkyfehler sowie für oktaedrische und tetraedrische Frenkelfehler in den γ‐Phasen der Cu‐I‐Halogenide wird näherungsweise unter der Voraussetzung eines starren Gitters berechnet. Sie beträgt für Schottkyfehler und Oktaederfehler 40 bis 50 kcal/mol und liegt für Tetraederfehler in der Größenordnung von Null kcal/mol. Durch Anwendung derselben Näherung auf NaCl, KCl und AgBr und durch Vergleich mit experimentellen Werten wird ihre Zulässigkeit überprüft.

Der aus der niedrigen Fehlerbildungsenergie für Tetraederfehler vermutete hohe Fehlordnungsgrad der Cu‐Ionen wird durch Röntgen‐Zählrohraufnahmen an pulverförmigem γ‐CuJ nachgewiesen. Aus dem Vergleich beobachteter und berechneter Strukturfaktoren werden Schottky‐ und Oktaederfehler über 2% ausgeschlossen, nicht aber Tetraederfehler. Die beste übereinstimmung zwischen beobachteten und berechneten Strukturfaktoren (3 bzw. 4%) wird mit Fehlordnungsmodellen erzielt, bei denen ein hoher Prozentsatz der Cu‐Ionen nicht zur Interferenz beiträgt.
Sound Absorption in Liquid Acetic Acid in the Frequency Range Between 0.3 to 1.5 GHz
Authors: Bader F. , Plaß K. G.
Published: March 2014

The sound absorption of liquid acetic acid has been measured in the frequency range between 0.3 to 1.5 GHz. In this frequency range a relaxation step has been found with a relaxation frequency of about 700 MHz. The molecular processes which possibly cause the measured acoustical relaxation are discussed.
Polarisation der Elektronenbanden von Aromaten 9. Mitteilung: Benzo(b)phenazin, Benzo(b)phenazin‐N‐oxid, Benzo(b)phenazin‐N.N' ‐dioxid
Authors: Bergmann D. , Kräßig R. , Kummer F. , Seiffert W. , Zimmermann H.
Published: March 2014

Die Elektronen‐ und Polarisationsspektren von Benzo(b)phenazin‐N.N'‐dioxid I, Benzo(b)phenazin‐N‐oxid II und von Benzo(b)phenazin III wurden gemessen und mit Hilfe semiempirischer Modellrechnungen nach der Methode von Pariser, Parr und Pople (PPP) klassifiziert. Die angeregten Elektronenzustände von I bis III wurden untereinander korreliert und an die Terme des Tetracens IV angeschlossen. Die intensiven Banden der Heterocyclen lassen sich mit dem Perimetermodel! von Platts als1La‐,1Lb‐und1Bb‐Übergänge deuten. Einige weitere schwache Banden in den Spektren der N‐Oxide I und II stehen in enger Beziehung zur Anregung der NO‐Gruppen. Die π‐Elektronendichten und π‐Bindungsordnungen von I bis IV werden mitgeteilt.
Orientational Intermolecular Potentials in Ionic Hydration Shells from Micro‐dynamic Data
Authors: Hertz H. G.
Published: March 2014

From the probability to find two molecular particles bound to one another for a sufficiently long time a lower limit of binding potential is derived. The effective potentials regard variation of the distance as well as the orientation of the molecules. The afore‐mentioned probabilities can be obtained from self‐diffusion data and molecular reorientation times. For water an effective mean potential Ē ≥ 1320 cal/mol with an estimated maximum depth Emax ≥ 2320 cal/mol was obtained. With proper modification of the model one finds flatter potentials in the hydration sphere of structure breaking ions and deeper potentials in the hydration shell of structure forming ions. Some numerical examples are given. Relations regarding correlated motions are presented which also give informations about the depth of the potential.
Gitterschwingungsspektren. VIII. Mitteilung [1] IR‐ und FIR‐Spektren von Barium‐ und Strontiumhalogenidmonohydraten
Authors: Lutz H. D. , Klüppel H.‐J. , Fehér M. , Bursian S.
Published: March 2014

Die IR‐Spektren (33–4000 cm−1) der Erdalkalimetallhalogenid‐Monohydrate: SrCl2 H2O, SrBr2 · H2O, SrJ2 · H2O, BaCl2 · H2O, BaBr2 · H2O und BaJ2 · H2O sowie der deuterierten und partiell deuterierten Verbindungen werden mitgeteilt und unter Zugrundelegung einer Faktorgruppenanalyse zugeordnet. Die aus den inneren Schwingungen der H2O‐Moleküle berechneten Kraftkonstanten zeigen. daß die Stärke der OH‐Bindungen des Kristallwassers (Valenzkraftkonstanten) von der Größe des Kationenfeldes abhängig ist, während die Deformationskraftkonstanten vornehmlich von den schwachen Wasserstoffbrücken zu den Halogenidionen beeinflußt werden. Die Translationsschwingungen der Erdalkalimetallhalogenid‐Monohydrate, deren Schwingungsformen aus den Symmetriekoordinaten abgeleitet wurden, werden beim Übergang von den Strontium‐ zu den Bariumverbindungen trotz zunehmender Masse der Metallionen zu höheren Wellenzahlen verschoben.
Das n1–6/n2–6‐Potential
Authors: Schramm Bernhard
Published: March 2014

Zur Beschreibung makroskopischer Eigenschaften der Materie wird ein zwischenmolekulares Potential mit vier freien Parametern vor‐geschlagen, das durch Verknüpfung von zwei Lennard‐Jones‐n‐6‐Potentialen am Minimum entsteht. Am Beispiel von Argon wird gezeigt, daß ein solches Potential die Beschreibung des zweiten Virialkoeffizienter. und der Viskosität im Rahmen der heute vorliegenden Meßgenauigkeit gestattet.
Theorie des Energieübertragungsprozesses Schwingung—Rotation
Authors: Hess Peter
Published: March 2014

Ausgehend von der Annahme, daß es beim Energieübertragungsprozeß Schwingung—Rotation auf das Verhältnis von Rotationszeit zu Schwingzeit ankommt, wird eine Theorie dieses Übergangsprozesses entwickelt. Der Isotopeneffekt wird bei den Systemen CH4CD4, SiH4SiD4, PH3PD3, AsH3AsD3 und C2H4C2D4 richtig beschrieben. Heraus fällt nur das System NH3ND3. Am Beispiel des Methans wird gezeigt, daß die Theorie auch die richtige Temperaturabhängigkeit der Übergangswahrscheinlichkeiten liefert. Der Einfluß des Wechselwirkungspotentials wird in Form eines konstanten Faktors erfaßt, der evtl. noch andere Anteile enthält.
Spectra of Matrix Isolated Metal Atoms and Clusters
Authors: Meyer B.
Published: March 2014

The matrix isolation spectra of all of the 40 presently known atomic metal species show strong matrix effects. The transition energies are increased, the bands are broad and exhibit splitting of sublevels which are degenerate in the gas phase. Several models have been proposed for splitting of levels, but basic effects are not yet understood, and spectra cannot be predicted, yet it is possible to correlate gas phase and matrix in many of the systems. Selective production of diatomics and clusters via thermal and optical annealing of atomic species can be monitored by optical spectra, but yields spectroscopically complex systems which, however, especially in the case of transition metals, can be used as precursors in novel chemical reactions. A combination of absorption, emission, ir, Raman, ESR, and other methods is now quickly yielding data which will help correlate the increasing wealth of existing data.
Infra‐Red Laser‐Induced Photochemistry in Matrices
Authors: Poliakoff M. , Davies B. , Mcneish A. , Tranquille M. , Turner J. J.
Published: March 2014

IR laser irradiation of 13C18O enriched Fc(CO)4, isolated in Ar, Xe and CH4 matrices at 20 K provides the first examples of selective IR laser‐induced reactions in the solid state. The reactions display not only isotopic and stereo‐chemical selectivity but also selectivity between molecules isolated in different substitutional sites in the matrix.
Electrolytic Growth and Dissolution of Oxide Layers on Silicon in Aqueous Solutions of Fluorides
Authors: Genscher H. , Lübke M.
Published: March 2014

The growth and dissolution of oxide layers on silicon has been studied under illumination and in the dark by analyzing current transients at different voltages in solutions of NH4F of various concentrations at pH values between 1 and 4.5. When the oxidation rate of the silicon at high enough anodic bias and, for n‐type specimens, high enough illumination intensity exceeds the rate of oxide dissolution in the fluoride, the film grows until it has reached a thickness where the dissolution is rate‐determining for the net process. At higher voltages the current begins to oscillate. The data give some insight into the composition of the oxide layers and their electronic and ionic properties.
Absolute Measurement of the Thermal Conductivity of Electrically Conducting Liquids
Authors: Assael M. J. , Charitidou E. , Georgiadis G. P. , Wakeham W. A.
Published: March 2014

A new instrument for the measurement of the thermal conductivity of electrically conducting liquids by the transient hot‐wire method is described. The instrument has features in common with earlier versions but employs a novel technique for the insulation of the hot‐wire. Absolute measurements of the thermal conductivity of water, methanol and ethanol are reported at atmospheric pressure and in the temperature range 295 — 350 K. The overall uncertainty in the reported thermal conductivity data is estimated to be ±0.5%. The data for water are consistent with internationally recommended reference values of slightly inferior accuracy.
13C NMR Study of the Interaction of N,N‐Dimethylamides and N,N‐Dimethylamidines with the Nitroxide Radical
Authors: Wawer Iwona , Kotodziejski Waclaw
Published: March 2014

13C NMR contact shifts δ induced by the 2,2,6,6‐tetramethylpiperidine nitroxide radical (TMPN) were measured for N,N‐dimethylacetamide (DMA) and N,N‐dimethylformamide (DMF) in several solvents and for 5 different N,N‐dimethylamidines in acetone‐d6. The shifts δ were straight linear functions of the TMPN concentration CR and were dependent on the electron acceptor properties of the solvents, thus proving the electron donor‐acceptor nature of the interactions between the radical and the other components of a solution. It was found that the radical induced contact shift enables one to detect differences in the electron acceptor properties of methyl groups within a diamagnetic molecule. In particular the different linear relationships between ln(dδ/dCR) and the solvent acceptor number AN was obtained for each methyl group of DMA. In all the compounds studied the N‐methyl group in the conformation antiperiplanar to the double bond (C = O in amides, C = N in amidines) appeared to be a better electron acceptor site than the N‐methyl group in the synperiplanar conformation. On the basis of dδ/dCR values some conjugation between the aromatic ring and C = N bond π‐electrons in arylacetamidines and in arylformamidines is suggested.
Isotopenselektive Dissoziation von SF6 mit einem Dauerlicht‐CO2‐Laser
Authors: D'Ambrosio C. , Fusz W. , Kompa K. L. , Schmid W. E.
Published: March 2014

SF6 was dissociated by a focussed cw CO2 laser at the 10P20 and 10P32 lines. Isotope selectivity > 10 was observed at 0.25 to 0.5 mbar. Collisions play no role in the focus, whose radius is smaller than the mean free path length. But most of the reaction occurs in the conical region of the beam, with radius up to 1 mm. Although collisions are not negligible in this part of the beam, they are not sufficient to destroy selectivity. — Both isotopes diffuse into the beam only after preheating to more than 1000 K. So, obviously, selective excitation is possible at such a high temperature. — Analytical formulas were derived for the radial (r) distribution of temperature T and its dependence on laser power P, molecule density n and absorption cross section σ. Because of the temperature dependence of σ and n and of the heat conductivity, T depends only on the 7th root of σnPlnr. This temperature distribution was used for a numerical calculation of the conversion rate, which was then compared with the experimental yields. The observed conversion can only be explained, if the vibrational temperature is about 110 K higher than the translational. — The observed quantum yield is much smaller than for pulsed excitation. But optimization by means of our formulas shows that it could be raised by orders of magnitude, so that application for practical isotope separation is conceivable.
The Reactions of Fluorine Atoms with Normal and Deuterated Methanols
Authors: Khatoon Tayyaba , Hoyermann K.
Published: March 2014

The reactions of fluorine atoms with normal and deuterated methanols have been studied at low pressure using a fast discharge flow reactor. Samples were withdrawn continuously via a molecular beam sampling system and were analyzed by a mass‐spectrometer. — The rate constants have been determined relative to the reaction

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for the reactions (1)–(4) were found as k1a/k1b = 0.40/0.60; k2a/k2b = 0.37/0.63; k3a/k3b = 0.39/0.61; and k4a/k4b = 0.36/0.64.
Direct Determination of CH2(ã1A1) Removal Rates by C2H2 and C6H6
Authors: Hack W. , Koch M. , Wagner H. Gg. , Wilms A.
Published: March 2014

Gas phase reactions of CH2(ã1A1) with benzene C6H6 and acetylene C2H2 were investigated at room temperature. CH2(ã1A1) was generated by laser photolysis of CH2CO at λL = 308 nm and the reactions were monitored directly by measuring the removal of CH2(ã1A1) with laser‐induced fluorescence (LIF). For the measurement of the formation rate of 3CH2 by physical deactivation LMR detection was used. The total removal of CH2(ã1A1) was found to be very efficient with rate constants of 2.4 ± 0.5 and 2.2 ± 0.2 (in 1014 cm3/mol s) for C6H6 and C2H2, respectively. The physical deactivation of 1CH2 to 3CH2 is about 30 resp. 22 percent of the total removal rate. Activation rates of 3CH2 to 1CH2 are give
Unusually Slow Formation of Ion‐pair Charge‐transfer Complex Between 4,4′‐bipyridinium and Tetrakis[3,5‐bis(trifluoromethyl)‐phenyl] borate in Organic Solutions
Authors: Nagamura Toshihiko , Sakai Kenkichi
Published: March 2014

4,4′‐Bipyridinium salts with tetrakis[3,5‐bis(trifluoromethyl)‐phenyl]borate anion (abbreviated to TFPB−) showed a charge‐transfer (CT) absorption above 350 nm with a discrete peak at about 475 nm in 1,2‐dimethoxyethane and at 420 nm in methanol. The absorbance of a CT band increased very gradually to the equilibrium dependent on temperature. The CT fluorescence showed similar very slow growth. The observed time‐dependences of absorbance and fluorescence were well explained by the temperature‐dependent formation and dissociation of CT complexes. Very slow growth was attributed to the unusually small pre‐exponential factor, which was most probably due to the extraordinary bulkiness of TFPB−
Multinuclear Spin‐Lattice Relaxation Time Studies of Supercooled Aqueous LiCl‐Solutions
Authors: Lang E. W. , Prielmeier F. X.
Published: March 2014

Recent deuteron (2H) spin‐lattice relaxation time (T1) measurements in undercooled 11 m LiCl/D2O solutions are supplemented by proton (1H) and lithium (6Li)—T1 as well as self‐diffusion coefficient measurements in undercooled 11 m LiCl/H2O solutions. The motional model for orientational fluctuations, proposed recently to interpret the 2H — T1 experiments, is slightly modified and is shown to describe the relaxation time curves of all nuclei (2H, 1H, 6Li) with only one adjustable parameter for light and heavy water. Self‐diffusion coefficients serve to calculate the contribution to the relaxation rates from positional fluctuations of the spin‐bearing particles. It is found that D(1H) > D(7Li) and that the proton mobility is less strongly slowed down when the temperature is lowered towards the glass temperature. Possible relations between this excess proton mobility and a recently observed excess proton conductivity are discussed.
Cyclic Voltammograms of Thin Film Cobalt Phthalocyanine Derivatives, Assignment of Each Cathodic Wave Formation of Protonated Species of Cobalt(I) Phthalocyanines
Authors: Kusuda Kusuke , Shiraki Kaneto , Yamaguchi Hidemasa
Published: March 2014

Cyclic voltammograms(cvs) of thin films of (29H, 31H,‐phthalocyaninato‐N29, N30, N31, N32)cobalt(II): CoPc (1), CoPc(COOH)4 (2), and monomeric CoPc(COOH)8 (3) shown in Fig. 1 have been investigated. Cv of 2 on a glassy carbon electrode, in a N2 saturated 1 M sulfuric acid solution, shows four cathodic waves at 0.10 V (a), —0.20 V (b), —0.48 V (c), and —0.73 V (d) vs. see. Each wave is assigned as follows; both a and b: redox of central Co(II)/α‐form of HCo(I)Pc(COOH)4 (4), c: redox of 4/H2Co(I)Pc(COOH)4 (6), d: formation of H3Co(I)Pc(COOH)4 (7). Incomplete air oxidation of 7 gives a film β‐form of HCoPc(COOH)4 (5) which showed a cathodic wave at — 0.56 V vs. see (d) to give 7. Chemical reduction of 2 with Na2S was followed by cv of thin film of the reaction mixture. Protonation of the product gives semistable film of 5. These assignments are based on the visible spectra, color change and cv behavior of the thin films of 2 under polarization at various potentials. Cv of 3 shows four reversible cathodic waves corresponding to that of 2. Reversibility of the forth wave (e) seemed to relate strongly with the character and the number of the substituent on the macrocyclic ring.
Impedance Studies of Copper in Alkaline Solutions, Especially During Electroless Plating
Authors: Wanner Michael , Wiese Harm , Weil Konrad Georg
Published: March 2014

An impedance study of the electrochemical double layer of copper in an electroless copper plating bath was performed. Of the bath components (formaldehyde, ethylenediamine‐tetraacetic acid (EDTA), CuEDTA2−, NaOH, Na2SO4, and NaHCOO) only the influence of hydroxide on the double layer is visible from capacitance data. The estimated surface coverage of hydroxide at the mixed potential of the electroless plating process is about 10%. On copper single crystal surfaces the OH−‐adsorption shows specific characteristics. Due to a surface reconstruction these characteristics, however, disappear with time after the immersion of the electrode. During the deposition process high electrode capacitances are measured (200–500 μF/cm2). They are mainly caused by a surface roughness on the microscopic scale. When the deposition process is terminated, the surface relaxes within about 10 minutes. The addition of cyanide or Gafac (a mixture of organic esters of phosphoric acid) to the electroless plating bath markedly influences the capacitance data. However, always a correlation between the deposition rate and the electrode capacitance is observed. If, on the other hand, at potentiostatic cupric ion reduction formaldehyde in the plating bath is substituted by ethylenediamine, which also catalyzes the CuEDTA2−‐reduction, the capacitance values decrease with increasing deposition current. Presumably, in the first case the nucleation rate dominates the deposit growth, while in the second case the opposite is true.
Dielectric Behaviour at High Pressure of Cyclo‐Octanol
Authors: Poser Uwe , Würflinger Albert
Published: March 2014

The phase behaviour and dielectric relaxation of cyclooctanol has been studied in the temperature range 240 — 300 K and up to pressures of 300 MPa. Two recently found pressure‐induced solid phases have been confirmed and designated as orientationally disordered ones. The complex dielectric permittivity for the orientationally disordered phases is determined as a function of pressure and temperature for frequencies between 1 kHz and 13 MHz. The loss curves are described with modified Debye theories and the Jonscher equation. The results are compared with previous findings on smaller cyclic alcohol
Extraction of Citric Acid by n‐Octanol and n‐Hexanol
Authors: Apelblat Alexander , Manzurola Emanuel
Published: March 2014

Extraction equilibria in the citric acid‐water‐n‐octanol and citric acid‐water‐n‐hexanol systems were investigated at 298.15 K. The proposed partition mechanism includes formation of the complex, H3Cit(H2O)4(ROH)4, with the equilibrium constant K = 0.102 for n‐octanol and K = 0.237 for n‐hexanol. Activities of alcohols in the organic phase and activity coefficients of citric acid in water were determined by a numerical integration of the Gibbs‐Duhem equation.
Löslichkeit und thermodynamische Daten von Eisen(II)‐Hydroxid durch analytische Bestimmung des Eisens und Leitfähigkeitsmessung im System Eisen‐Wasser
Authors: Bohnsack G.
Published: March 2014

In a solution of iron(II) hydroxide produced by equilibration of pure oxygen free water with pure metallic iron we have determined the constant of the protolysis equilibrium combining analysis of the iron concentration with conductivity measurement. — Following the reaction between steel wool and pure water in a closed system by conductivity measurement a conductivity maximum has shown a temporary supersaturation with a subsequent steady state of saturation of iron(II)‐hydroxide in a equilibrium with a not well defined solid. By determination of the iron concentration and of manganese and nickel as impurities we could estimate using the protolysis constant the composition of the saturated solution of iron(II)‐hydroxide. — From the measured data we could also derive the constants describing the properties of iron(II)‐hydroxid
1H‐NMR Studies of the Systems Ta1−xVxHy(0.0 ≤x≤ 1.0; 0 <y≤ 0.9), and Nb1−xVxHy(0.0 ≤x≤ 0.5; 0 <y≤ 0.9). Magnetic Susceptibility, Knight Shift, and Longitudinal Relaxation
Authors: Richter Karl‐Hermann , Weiss Alarich
Published: March 2014

Both the magnetic susceptibility χ(x, y) and the1H‐Knight shiftKH(x, y) of the ternary systems Ta1−xVxHyand Nb1−xVxHywere studied by high resolution1H‐NMR Fourier transform spectroscopy. χ(x, y) always increases as a function of the vanadium concentrationxand decreases with increasing hydrogen concentrationy. In contrast, the1H‐Knight shiftKH(x, y) is strongly influenced by vanadium at low hydrogen concentrations. For both systems the shape ofKH(x, y) behaves analogously to the shape ofKH(x, y) of the systems Ta1−xTixHyand Nb1−xTixHy. The same similarities were found with respect to the temperature dependence of the1H‐Knight shift.KHis nearly independent of temperature for the binary systems TaHyand NbHywhereas it increases with increasing temperature for the systems Ta0.9V0.1Hyand Nb0.9V0.1Hy. Such a behavior was observed for the ternary system Ta0.9Ti0.1Hy, too. From the temperature dependence of χ(T) andKH(T) we conclude that the V‐3d‐wavefunctions as well as the Ti‐3d‐wavefunctions produce a negative hyperfine field at the proton site. In contrast, we find a positive hyperfine field at the proton site caused by the spin part of the d‐electrons in the case of TaHyand NbHy. Additionally, measurements of the longitudinal relaxation timeT1were carried out on the systems TaHy—Ta0.9V0.1Hy. At low hydrogen concentrations the dipolar contribution toT1differs strongly for both systems. This may be a consequence of trapping processes of the hydrogen atoms in the neighborhood of the vanadium atoms.
Critical Assessment of Thermodynamic Properties and Phase‐Diagram Calculations of K‐KCl and K‐KBr Systems
Authors: Rand M. , Gaune‐Escard M. , Bros J. P. , Gaune P.
Published: March 2014

All the available thermodynamic information on the K‐KCl and K‐KBr systems has been collected and used, through an optimisation procedure, to check the thermodynamic consistency of those experimental thermodynamic data. Optimized sets of parameters for the excess Gibbs energy of mixing of the K‐KX liquid solutions have been obtained; the liquid phase was modelled as a simple mixture of K and KX, exactly equivalent to a “sublattice”‐type model, the excess Gibbs energies being represented by Redlich‐Kister polynomials. Agreement between calculated and experimental phase diagrams and thermodynamic functions is within the experimental uncertainties.
Die zweiten Virialkoeffizienten der Systeme N2–O2und N2–NO von 87 K bzw. 124 K bis 475 K
Authors: Fostiropoulos K. , Natour G. , Sommer J. , Schramm B.
Published: March 2014

Measurements of second interaction virial coefficients of mixtures N2–O2and N2–2NO are presented. Temperatures range from the boiling temperature of the gases up to 475 K. New experimental data of second virial coefficients for pure O2and NO are presented also and are critically compared with literature data. The amount of dimers in gaseous NO is calculated with the law of corresponding states.

Some thermodynamic aspects of the N2–NO system are discussed.
The Dissolution of N2 and of H2 in Water from Room Temperature to 640 K
Authors: Alvarez Jorge , Crovetto Rosa , Fernández‐Prini Roberto
Published: March 2014

The solubilities of H2 and of N2 in water have been determined over a wide temperature range. The thermodynamic analysis of the data allowed the calculation of Henry's constants (k∞H) as function of temperature from room temperature to 636 K; other thermodynamic quantities of dissolution have been derived from the temperature dependence of k∞H. With a semiempirical perturbation method it is possible to describe the experimental behaviour and to predict the partial molar volume and heat capacity of the solutes over all the temperature range. This calculation procedure requires the knowledge of the hard‐sphere radii of the solute gases and their (linear) temperature dependence which may be determined from solubility data covering only a reduced temperature range extending to about 400 K.
Effect of Lipid Headgroups and (Nonelectrolyte) Solution on the Structural and Phase Properties of Bilayer Membranes
Authors: Cevc Gregor
Published: March 2014

Properties of the biological and model membranes can be regulated by the lipid polar headgroups and their bathing solution. This occurs primarily via changes in the interfacial hydrophilicity and hydration, which are mostly a result of the lipid deprotonation or osmotic dehydration. Steric or electrostatic effects normaly play a minor role. Therefore, phosphate derivatization or protonation, further changes that decrease the lipid capacity for the hydrogen bonding and lower the interfacial affinity for binding water, as well as any system alterations that diminish the amount of interbilayer water can all cause the lipid chain melting phase transition temperature, the persistence of the lamellar lipid phase, and the colloidal stability of vesicle suspension, but also the height of the membrane permeability barrier to decrease, whereas lipid protonation or dealkylation have the reverse effect. – Lipid bilayers and their adjacent solution behave as single thermodynamic entity. Changes in the polar headgroup region and in the solvent composition consequently can regulate not only the membrane capacity for molecular or supramolecular reorganisation (e.g. phase changes or membrane fusion, respectively) but moreover may govern the short‐range intermembrane (e.g. hydration) forces and, to some extent, affect the membrane‐solute interactions. These effects are therefore of considerable interest and relevance for the studies and understanding of membrane binding and transport.