bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of conductive polybenzoxazines by oxidative polymerization
Authors: Kiskan Baris , Yagci Yusuf , Sahmetlioglu Ertugrul , Toppare Levent 
Published: February 2007

AbstractSoluble and thermally curable conducting high molecular weight polybenzoxazine precursors were prepared by oxidative polymerization 3‐phenyl‐3,4‐dihydro‐2H‐benzo[e][1,3] oxazine (P‐a) alone and in the presence of thiophene (Th) with ceric ammonium nitrate in acetonitrile. The structure of the precursors was confirmed by FTIR, 1H NMR, and DSC measurements, indicating the presence of a cyclic benzoxazine structure, together with small but varying amount of a ring opened phenolic structure. The resulting polymers exhibit conductivities around 10−2 S cm−1 and undergo thermal curing at various temperatures. Attempts to copolymerize P‐a with another electroactive monomer, pyrrole (Py), by a similar redox process were unsuccessful, which was attributed to the unfavourable oxidation potential of Py. The cured products exhibited high thermal stability but lower conductivity, than those of the precursors. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 999–1006, 2007
Gas solubility of carbon dioxide in poly(lactic acid) at high pressures: Thermal treatment effect
Authors: Oliveira N. S. , Dorgan J. , Coutinho J. A. P. , Ferreira A. , Daridon J. L. , Marrucho I. M. 
Published: January 2007

AbstractThe sorption of carbon dioxide in glassy Poly(lactic acid) (PLA) films was studied by quartz crystal microbalance (QCM) at high pressures. Two thermal treatments, melted and quenched, were performed in PLA with two different L:D contents, 80:20 and 98:2, films and compared with a third thermal protocol, annealed, and used in a previous work. The results obtained show that for pressures higher than 2 MPa, the carbon dioxide solubility is larger in PLA 80:20 than in PLA 98:2, indicating that the L:D plays a dominant role on this property. The thermal treatments only affect the gas solubility in PLA 98:2. Sorption isotherms at temperatures 303, 313, and 323 K, below the glass transition temperature of the polymer, and pressures up to 5 MPa were measured and analyzed with three different models, the dual‐mode sorption model, the Flory–Huggins equation, and a modified dual‐mode sorption model where the Henry's law term was substituted by the Flory–Huggins equation. This last model performs especially well for CO2 in PLA 80:20, due to the convex upward curvature of the solubility isotherms for that system. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 616–625, 2007
Wide angle X‐ray diffraction and Fourier transform infrared dichroism studies of stretched‐recovery‐restretched process of polyurethane/clay nanocomposite
Authors: Chen Guangming , Ma Yongmei , Zheng Xianjun , Xu Guangyang , Liu Jun , Fan Jiaqi , Shen Deyan , Qi Zongneng 
Published: February 2007

AbstractAn intercalated polyurethane (PU) /clay nanocomposite was prepared by in situ intercalative polymerization. The PU/clay nanocomposite pellet or film samples were stretched‐recovery‐restretched, using selfmade microstretching tools. The changes of the basal spacings of clay and the orientation of polymer chain segments during the stretched‐recovery‐restretched process were studied by wide angle X‐ray diffraction (WAXD) and Fourier transform infrared (FTIR) dichoism techniques. The WAXD results show that the basal spacing of clay did not change obviously, indicating that no macromolecular chains entered or moved out of the interlayer space, and the orientations of both hard and soft segments inside the interlayer space did not change obviously, either. The FTIR dichroism tests suggest that outside the interlayer space, the orientation of the hard chain segment increased, decreased, and then increased again during the stretched‐recovery‐restretched process. However, no obvious changes of the degree of orientation of the soft segment were observed during the processes, the slightly orientation might be released during the relaxation process before the measurements. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 654–660, 2007
Differential retention of α‐vitamin E is correlated with its transporter gene expression and growth inhibition efficacy in prostate cancer cells
Authors: Ni Jing , Pang See‐Too , Yeh Shuyuan 
Published: January 2007

AbstractBACKGROUNDEpidemiological studies showed Vit E has protective effects against prostate cancer (PCa). Interestingly, different prostate cancer cells have different sensitivity to α‐Vit E or VES treatment. The goal of this study is to determine whether cellular Vit E bioavailability and its transport proteins are important contributing factors.METHODSα‐Vit E and its ester form, VES, were used to treat prostate cancer LNCaP, PC3, and DU145 cells, and their growth rates were determined by MTT assay. Cellular levels of Vit E were quantified using HPLC as the index of bioavailability. The expression levels of Vit E transport proteins were determined by real‐time PCR.RESULTSAmong these PCa cells, only LNCaP cells were sensitive to 20 µM α‐Vit E treatment, while both LNCaP and PC3 cells were sensitive to 20 µM VES treatment. Coordinately, cellular levels of α‐Vit E and VES positively correlated to their inhibitory effects. Further study found expression levels of Vit E transport proteins, including tocopherol associated protein (TAP), scavenger receptor class B type I (SR‐BI), α‐tocopherol transfer protein (TTP), and ATP binding cassette transporter A1 (ABCA1), were different in various PCa cells, which may contribute to cellular Vit E bioavailability. This notion is further supported by the findings that overexpression or knockdown of TTP could coordinately alter cellular α‐Vit E levels in PCa cells.CONCLUSIONAntiproliferative efficacy of α‐Vit E is correlated with its cellular bioavailability in PCa cells. Modulating the expression of the efflux or influx transporters could sensitize the growth inhibition efficacy of Vit E in prostate cancer cells. Prostate 67: 463–471, 2007. © 2007 Wiley‐Liss, Inc.
The influence of antimony on the optical quality of highly strained GaInNAs/GaAs QWs investigated by contacless electroreflectance
Authors: Kudrawiec R. , Yuen H. B. , Bank S. R. , Bae H. P. , Wistey M. A. , Harris James S. , Motyka M. , Gladysiewicz M. , Misiewicz J. 
Published: February 2007

AbstractContactless electroreflectance (CER) has been applied to study the influence of Sb atoms on the optical quality of highly strained GaInNAs/GaAs quantum wells (QWs). A set of QWs grown under various antimony fluxes has been analyzed in this work. The broadening of the CER resonance has been used as an indicator of the QW quality. It has been observed that broadening of the CER resonance related to the ground state transition decreases about three times (from ∼60 meV to 20 meV) after the incorporation of antimony into GaInNAs/GaAs QWs. Moreover, it has been observed that the broadening parameter does not decrease with the rise of antimony content from 0.5% to 2.0%. It means that only 0.5% Sb is enough to improve the optical quality of GaInNAs/GaAs QWs. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation spectroscopy on a single self assembled quantum dot
Authors: Seidl S. , Högele A. , Kroner M. , Karrai K. , Warburton R. J. , Garcia J. M. , Petroff P. M. 
Published: February 2007

AbstractWe present high resolution modulation spectroscopy on single quantum dots and discuss briefly the differences to other spectroscopy techniques. We use this technique to study the excitonic fine structure while charging the quantum dot and applying mechanical strain to it. We also show that the fine structure can be used as a polarization analyzer. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contactless modulated reflectivity of quasi 0D self‐assembled semiconductor structures
Authors: Sęk G. , Kudrawiec R. , Motyka M. , Poloczek P. , Rudno‐Rudziński W. , Podemski P. , Misiewicz J. 
Published: February 2007

AbstractTwo different approaches of contactless modulated reflectivity spectroscopy, namely photoreflectance (PR) and contactless electroreflectance (CER), have been used for the investigation of quasi 0D self‐assembled semiconductor structures, like quantum dots or quantum dashes. First of all, the advantages and disadvantages of both techniques are discussed with respect to that certain application, including the problems of spurious background signals and below‐band‐gap oscillations. Second, the modulation mechanism in photoreflectance of quantum dots is analyzed by comparing PR, CER, photoluminescence excitaion and photoreflectance excitation. Finally, recent results regarding the modulation spectroscopy study of several types of structures including quasi 0D objects will be presented. It will concern the following aspects in particular: wetting layer (WL) thickness determination; quantum dots formation at the 2D–3D Stranski–Krastanov growth transition for the case of Inx Ga1–x As/GaAs quantum dots; probing the excited states and electronic structure in novel material/design QDot/QDash systems and characterization of the QD‐based laser structures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The application to micrometeorology of the theory of turbulent flow over rough surfaces
Authors: Sutton O. G. 
Published: February 2007

AbstractIt is now well established that turbulent flow near the surface of the earth is usually of the type known as “aerodynamically rough”, and the present paper discusses the implications of this for diffusion. The various theories of rough flow are discussed and the conclusion reached that the formulation due to Rossby and Montgomery, in which the influence of the surface irregularities dies out with height, is the treatment most appropriate for meteorology, because of the relatively great depth of the layers dealt with as compared with wind tunnel boundary‐layer investigations. It is shown that the introduction of a characteristic parameter termed by the author the macroviscosity, defined as the product of the friction velocity and the roughness length, enables a single logarithmic profile to be defined for both rough and smooth flow. Finally, the theory of atmospheric diffusion previously advanced by the writer for smooth flow is extended to rough flow in conditions of neutral equilibrium, and shown to be in good agreement with observation.
Observations of rain from non‐freezing clouds
Authors: Smith E. J. , Priestley C. H. B. 
Published: February 2007

AbstractA description is given of observations made in south‐east Australia of medium and heavy rain falling from clouds which were everywhere warmer than 0°C. Detailed observations were made visually from aircraft and these were supplemented by measurements of the radar echo intensities and drop size spectra within the clouds.The clouds were all deep cumulus and were over or near the sea. Great concentrations of relatively large water drops were observed in the upper levels of the clouds.
A new method of measurement of cloud‐water content
Authors: Warner J. , Newnham T. D. 
Published: February 2007

AbstractA new method of measurement of the liquid‐water content of clouds is described. It depends on the change of resistance of a paper tape on being moistened by cloud droplets which impinge directly on it. A continuous and permanent record of the liquid water can be obtained, and variations over distances of a few hundred feet can be detected. Measurements have been made using the technique on a number of cumulus and stratocumulus clouds, some characteristics of which are described.
Photoelectric measurements of the seasonal variations in daylight at Plymouth from 1947 to 1949
Authors: Atkins W. R. G. , Jenkins Pamela G. 
Published: February 2007

AbstractDaylight received on a horizontal surface has been measured for fourteen years using a Burt vacuum sodium cell and Cambridge thread‐recorder galvanometer. Mean monthly values of daily maxima, in kilolux, are tabulated, also mean monthly values of illumination in kilolux hours. These are compared with similar measurements at Kew in 1947 and 1948, obtained using a selenium cell. The kilolux hours for each month are shown as a percentage of individual years, with mean values for fourteen years and percentage range for variation. Annual totals were 108, 124 and 122 megalux hours for 1947, 1948 and 1949 respectively with 116 as the mean of the whole series. Between these and sunshine or rainfall there is no simple relation. Cloudless days are not the brightest owing to downward reflection from clouds. Darkest days in each month commonly show 17 to 40 per cent as many kilolux hours as do brightest, though smoke pollution may reduce illumination to 5 per cent.
Wind stress on water: An hypothesis
Authors: Munk W. H. 
Published: February 2007

AbstractThe form drag of wind on an irregular surface is found to equal the product of U2 (U is anemometer wind‐speed) and a function of the two‐dimensional spectrum of this surface. For a solid surface this function is, of course, independent of U and the form drag is proportional to U2, as observed over land. Over water, Neumann's frequency spectrum and the glitter measurements by Cox and Munk make this function proportional to U, and hence the form drag proportional to U3. The computed form drag is not far out of line with measurements by Van Dorn and others.The dependence of form drag on the ‘beam‐width’ and frequency spectrum of the surface roughness is discussed. The essential roughness statistic comes close to being the mean‐square slope of the surface, rather than being related to wave height or some other roughness length, as usually assumed. The slope statistics are governed by the high‐frequency part of the wave spectrum, and this feature accounts for the pronounced reduction of form drag by surface ‘slicks,’ and the relatively small effect of a limited fetch. The total drag, c1 U2 + c2 U3 (skin friction + form drag), must be larger at very high winds than if it followed a U2 law, as usually assumed.
On the space and time distribution of showers in a tropical region
Authors: Soane Christine M. , Miles V. G. 
Published: February 2007

AbstractCharts of daily rainfall in Southern Rhodesia show that the distribution of rain in space and time cannot be associated in any detail with features of the synoptic map.Displays of precipitation echoes on the screen of a 10‐cm radar situated at Salisbury have been photographed by time‐lapse camera giving great detail and continuity of record.It is found that echo displays associated with cumuliform cloud can be resolved into a few areas of echo activity which move continuously by a process of new echo formation. These moving areas have been termed ‘progressions’ and progression behaviour is described in terms of individual echo behaviour and in relation to other meteorological observations. The discovery of progressions has introduced order into a type of tropical shower activity which has previously been considered incoherent.
The local wind at Milfield, Northumberland
Authors: Meiklejohn Jane 
Published: February 2007

AbstractThere is a very strong local westerly wind at Milfield, which blows along the foot of the escarpment of the Cheviot Hills. It occurs in any synoptic situation which gives a surface wind between south‐west and west, and the presence of an inversion is not necessary for its appearance. The wind is not purely katabatic, and its main cause appears to be some feature of the local topography.
The brightness distribution of the overcast sky when the ground is snow‐covered
Authors: Petherbridge P. 
Published: February 2007

AbstractMeasurements have been made of the brightness distribution of a densely overcast sky when the ground was covered with snow. The distribution proved to be moze uniform than has been reported for normal ground conditions.The distribution was found to be somewhat asymmetric, which may have been due to differences in cloud thickness or to the local influence of inter‐reflections between the base of the cloud and the ground below.The averaged data were found to be represented with reasonable accuracy by the empirical formula: Bθ = 1/2 BZ (1 + cos θ) where Bθ = brightness of the sky at zenith angle θ and BZ = brightness of the sky at the zenith.The reflection factor of the snow was measured and found to be 80 per cent.
Airflow over an isolated hill
Authors: Scorer R. S. 
Published: February 2007

AbstractPerturbation theory is used to compute the vertical displacement of a uniform airstream passing over a solitary hill: first for a circular hill, then for a hill of oval section lying across the wind, obliquely to it and along it. The diagrams show contours of the vertical displacement at four different heights above the hill. It is significant that a small but steep‐sided oval hill produces almost as much displacement as a larger circular, less‐steep hill. When inclined obliquely to the airstream the pattern is very asymmetrical, the displacement being greater over the end of the hill that is farther down wind. A hill lying along the wind produces a very small effect.
A tangent arc of the halo of 24½ °
Authors: Visser S. W. , Alkemade C. T. J. 
Published: February 2007

AbstractA remarkable halo complex observed in Germany in 1944 is described and theoretically discussed. There appear to be two possible crystal forms. Only one, however, with an inclination of the pyramidal faces of 25° 14′ fulfills the theoretical conditions. As far as we know there is only one other observation of a tangent are of an uncommon halo (in the Netherlands in 1933). It requires an inclination of the pyramidal face of 54° 44′, just the angle measured by Clarke (1822). In both phenomena we are concerned with similar refraction in similar plate‐shaped ice crystals.
Wind profiles and the shearing stress — an anomaly resolved
Authors: Deacon E. L. 
Published: February 2007

AbstractReported failures of a generalized wind‐profile equation to predict correctly the shearing stress under certain conditions are found to be associated with low wind speeds close to the surface. The increase of drag coefficient of the surface‐roughness elements (e.g., grass blades) at low Reynolds numbers is the source of these discrepancies.
Long waves, lee waves and gravity waves
Authors: Ball F. K. 
Published: February 2007

AbstractIt is shown that the equation determining the streamlines of large‐scale atmospheric motions (jet streams and long waves) is similar to the equation determining the streamlines of small‐scale gravitational motions of a stratified liquid. Both motions are characterized by the occurrence of jets, the number of jets being determined by the value of a dimensionless parameter. Atmospheric flow at 500 mb is compared with theoretical solutions (derived by Long 1955) of the non‐linear equations for the flow of a stratified liquid. Linearization of the equation for large‐scale atmospheric motions leads to the Rossby wave equation, whereas linearization of the equation for the motion of a stratified liquid leads to Scorer's lee‐wave equation.
The composition of precipitation at Lerwick, Shetland
Authors: Oddie B. C. V. 
Published: February 2007

AbstractIt is shown that most of the salts deposited at Lerwick arrive as sea‐spray rather than in true precipitation. Mg, K and Na are present in very nearly the same proportions as in sea water: but there is a very great deficiency of chlorine, which, it is argued, can only be explained on Cauer's hypothesis that NaCl in aerosol form is dissociated and that Cl or HCl is released.
An experimental system for directly recording statistics of the intensity of atmospheric turbulence
Authors: Jones J. I. P. , Pasquill F. 
Published: February 2007

AbstractIt is demonstrated theoretically that the ‘filtering’ effects exerted on a turbulence record by taking averages over an interval s, for a total sampling time t, may be reproduced by simple electrical filters as far as the variance is concerned. The smoothed rectified output of such a filter may be recorded on a slowly moving chart and, with the further assumption of Gaussian distribution in the amplitudes of the fluctuations, may be read directly as a statistical mean of the standard deviation.A description is given of an experimental system, and of direct tests of its performance in recording the standard deviation of wind‐direction fluctuations when averaged over 5 sec and sampled over 3 min. Proposed applications are briefly outlined.
Atmospheric extinction of infra‐red radiation
Authors: Deirmendjian D. 
Published: February 2007

AbstractThe effects of scattering on the transmission of 2·6 to 12 micron radiation are analysed as a continuation of an earlier paper. Monochromatic extinction coefficients are determined on the basis of the original haze models and of the exact values of the complex index of refraction for water. The individual extinction cross‐sections are computed with a high degree of accuracy by means of a modified van de Hulst expression.The results are in good agreement with existing experimental determinations of window transmission except in the 8 to 12 μ region, where they support Roach and Goody's (1958) conclusion on the importance of wing absorption by molecular lines. The computed continuous spectrum of haze extinction presented graphically and in tables, further reveals interesting details which will be useful in determining the relative importance of absorption and scattering in atmospheric infra‐red radiation.A simple cloud model is also considered, and it is shown that even tenuous clouds may be quite opaque to infra‐red radiation over a wide band. In the window regions, clouds and dense hazes scatter a considerable portion of the incident radiation, thereby contributing to the infra‐red sky background usually attributed to black‐body emission.
The generation of wave energy at a fluid interface by the passage of a vertically moving slender body
Authors: Warren F. W. G. 
Published: February 2007

AbstractIn this paper an estimate is made of the energy absorbed by wave motion at the interface of two superposed fluids when a body passes from one fluid to the other. The fluids are supposed perfect, incompressible, and bounded only by the interface, and axi‐symmetric and symmetrical two‐dimensional cases are considered. The body is supposed to move vertically and approach the interface from a great distance, and after crossing the interface to recede to a great distance, the speed being kept steady throughout. It is assumed that there were no waves originally present at the interface and that no splashing occurs during the crossing. The linear approximation to irrotational waves is used at the interface, and the slender body approximation is used at the boundary of the body. Transform methods are used to solve the Laplace equation for the velocity potential. Expressions are found for the waves set up as the body crosses the interface, and the energy used to generate the waves is found from a calculation of the work done against the wave resistance. The wave energy may be regarded as the sum of the wave energies for two cases : one in which the density difference between the two fluids is small, and another, in which the density of the upper fluid is zero. For the special cases of a spheroid and a spindle‐shaped body, curves are shown of the wave energy against a dimensionless form of the inverse speed. Criteria are given for when maximum wave energy is developed for a thermal, and an estimate of this energy is made. This is done in Section 6.