bluuebunny/crossref_metadata_2025 huggingface dataset:
Synoptic flow patterns leading to the generation of north‐west African depressions
Authors: Prezerakos N. G.
Published: June 2010

This paper reports a study and analysis of the synoptic evolution of the atmospheric flow patterns that cause the formation of north‐west African depressions. The study uses mean 500 and 850 hPa heights and their anomalies, associated with the subcategories into which the north‐west African depressions have been classified. The time period under consideration covers the consecutive years from 1970 to 1974.

To study better the synoptic evolution and the separation of existing centres of action for each subcategory, charts of the mean 500 and 850 hPa heights and temperatures for 72, 48, and 24 h before the first appearance of a depression have been prepared. For the mean 500 hPa height field and for each subcategory, anomalies based on differences from the long‐term (1950–1973) average have been calculated (at the 0·01 statistical level of significance) for each grid point of the ‘anomaly’ fields. From the study as a whole it can be deduced that the synoptic flow patterns, which cause the generation of north‐west African depressions, are unstable baroclinic waves, at the synoptic scale, initiated in the middle troposphere over geographical regions far from the Atlas Mountains. These waves can be seen on the 500 hPa charts at least 72 h before the first appearance of the depressions on the mean sea‐level (MSL) charts for north‐west Africa. It also seems that the intensive low‐level tropospheric baroclinicity, which is most pronounced along the north‐west African coast, plays an important role in the initiation and self‐maintenance of the surface lows. Finally, the key atmospheric circulation system that causes these baroclinic waves to form must be a large‐scale ridge, often of a blocking type, located in the North Atlantic Ocean or north‐west Europe.
Thermo‐topographically induced boundary layer oscillations over the central Namib, southern Africa
Authors: Lindesay J. A. , Tyson P. D.
Published: June 2010

Diurnal and seasonal oscillations of the atmospheric boundary layer over the central Namib Desert on the west coast of southern Africa are examined. Both the vertical and horizontal structure of the thermo‐topographic airflow are contrasted with similar wind systems occurring over Natal on the east coast of the subcontinent. Thermo‐topographic airflows over the central Namib are found to have a regional significance frequently equalling or exceeding that of the general circulation. The strength, depth, and unusually clearly defined diurnal and seasonal oscillations of these winds render the central Namib a unique area for the study of boundary layer oscillations.
Recreation climate assessment
Authors: de Freitas C. R.
Published: June 2010

The study examines methods for assessing the atmospheric resource component of recreation environments. Beach use is selected as it is a highly weather sensitive recreational activity. The study area is King's Beach in Queensland, Australia. The nature of the relationship between beach climate and the enjoyment of recreational pursuits is taken to be a function of thermal, physical, and aesthetic components of the atmospheric environment. A body‐atmosphere heat‐budget model is used to integrate and isolate the thermal component of beach weather and enable identification of important non‐thermal recreational resource attributes of the atmosphere. Beach‐user sensory perception of on‐site atmospheric conditions expressed verbally is used to assess the physical and aesthetic components of the atmospheric environment. The immediate thermal environment of the beach user is the main contributing factor to assessments of the desirability of on‐site meteorological conditions, followed by the non‐thermal effects of cloud and wind. Rainfall events of half‐hour duration or longer have an overriding effect.
Isosceles Orthogonal Triples in Linear 2‐Normed Spaces
Authors: Cho Y. J. , Diminnie C. R. , Freese R. W. , Andalafte E. Z.
Published: June 2010

A triple (x, y, z) in a linear 2‐normed space (X, ‖.,.‖) is called an isosceles orthogonal triple, denoted |(x, y, z), if

|(.,.,.) is said to be homogeneous if |(x, y, z) implies |(ax, y, z) for all real a and it is additive if |(x1, y, z) and |(x2, y, z) imply that |(x1 + x2, y, z). In addition to developing some basic properties of |(.,.,.), this paper shows that under the assumption of strict convexity, every subspace of X of dimension ≤ 3 contains an isosceles orthogonal triple. Further, if (X, ‖.,.‖) is strictly convex and |(…,.) is either homogeneous or additive, then (X, ‖.,.‖) is a 2‐inner product space.
Regulators and Galois Stability
Authors: Ritter Jürgen , Weiss Alfred
Published: June 2010

Thanks to the existence of Galois stable orders the Fröhlich regulator associated to two lattices X and Y that are linked by a bilinear form determines a Galois homomorphism ρ from some character ring into the ideals of the corresponding field of definition. In this paper it will be shown that whenever the deviation between X and Y can be measured by an element of a certain genus class group the homomorphism ρ turns out to be a representing Galois homomorphism of that element.
Extremal Solutions of Evolution Inclusions Associated with Time Dependent Convex Subdifferentials
Authors: Papageorgiou Nikolaos S.
Published: June 2010

In this paper first we establish the existence of extremal solutions for evolution inclusions driven by time dependent convex subdifferentials, and then show that they are dense for the topology of uniform convergence on T=[0, b] to the solutions of the original system. Then these results are applied to establish “bang‐bang” type results for some classes of nonlinear infinite dimensional control systems. A few examples are also presented.
Impulsive Integral Inequalities with a Deviation of the Argument
Authors: Bainov D. D. , Hristova S. G.
Published: June 2010

In the present work are proved linear generalizations of the classical Gronwall‐Bellman's integral inequality on partially continuous functions with a constant deviation.
A surface‐temperature prediction model for porous asphalt pavement and its validation
Authors: Shao J , Lister P J , McDonald A
Published: June 2010

A numerical road‐ice prediction model is further developed to predict surface temperature and surface state for porous asphalt pavement, which is significantly colder at night and warmer at daytime than conventional asphalt pavement. The model is validated against temperature measurements on both porous and conventional asphalt pavements, using actual input data for the complete winter 1992/93. The validation of model rum at noon shows that, on average, the model has a near‐zero bias for minimum, maximum and overall hourly temperature forecasts. The model has the smallest standard deviation (0.78 °C) for minimum temperature forecasts and the largest standard deviation (1.92 °C) for maximum temperature forecasts. Nearly 90% of frost days are predicted. Model runs with different start times at 1200 1500, 1900 and 0000 show consistently good results.
Analysis of time course 1H NMR metabolomics data by multivariate curve resolution
Authors: Karakach Tobias K. , Knight Richard , Lenz Eva M. , Viant Mark R. , Walter John A.
Published: June 2010

Modeling NMR‐based metabolomics data often involves linear methods such as principal component analysis (PCA) and partial least squares (PLS). These methods have the objective of describing the main variance in the data and maximum covariance between the predictor variables and some response variable respectively. If the experiment is designed to investigate temporal biological fluctuations, however, the factors obtained become difficult to interpret in a biological context. Moreover, when these methods are applied to analyze data, an implicit assumption is made that the measurement errors exhibit an iid‐normal distribution, often limiting the extent of the information recovered. A method for the linear decomposition of NMR‐based metabolomics data by multivariate curve resolution (MCR), which has been used elsewhere for time course transcriptomics applications, is introduced and implemented via a weighted alternating least squares (ALS) approach. Measurement of error information is incorporated in the modeling process, allowing the least squares projections to be performed in a maximum likelihood fashion. As a result, noise heteroscedasticity resulting from pH‐induced peak shifts can be modeled, eliminating the need for binning/bucketing. The utility of the method is demonstrated using two sets of temporal NMR metabolomics data, HgCl2‐induced nephrotoxicity in rat, and fish (Japanese medaka, Oryzias latipes) embryogenesis. Profiles extracted for the nephrotoxicity data exhibit strong correlations with metabolites consistent with temporal fluctuations in glucosuria. The concentration of metabolites such as acetate, glucose, and alanine exhibit a steady increase, which peaks at Day 3 post dose and returns to basal levels at Day 8. Other metabolites including citrate and 2‐oxoglutarate exhibit the opposite characteristics. Although the fish embryogenesis data are more complex, the profiles extracted by the algorithm display characteristics that depict temporal variation consistent with processes associated with embryogenesis. Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd
Comparison of myocardial perfusion estimates from dynamic contrast‐enhanced magnetic resonance imaging with four quantitative analysis methods
Authors: Pack Nathan A. , DiBella Edward V. R.
Published: June 2010

Dynamic contrast‐enhanced MRI has been used to quantify myocardial perfusion in recent years. Published results have varied widely, possibly depending on the method used to analyze the dynamic perfusion data. Here, four quantitative analysis methods (two‐compartment modeling, Fermi function modeling, model‐independent analysis, and Patlak plot analysis) were implemented and compared for quantifying myocardial perfusion. Dynamic contrast‐enhanced MRI data were acquired in 20 human subjects at rest with low‐dose (0.019 ± 0.005 mmol/kg) bolus injections of gadolinium. Fourteen of these subjects were also imaged at adenosine stress (0.021 ± 0.005 mmol/kg). Aggregate rest perfusion estimates were not significantly different between all four analysis methods. At stress, perfusion estimates were not significantly different between two‐compartment modeling, model‐independent analysis, and Patlak plot analysis. Stress estimates from the Fermi model were significantly higher (∼20%) than the other three methods. Myocardial perfusion reserve values were not significantly different between all four methods. Model‐independent analysis resulted in the lowest model curve‐fit errors. When more than just the first pass of data was analyzed, perfusion estimates from two‐compartment modeling and model‐independent analysis did not change significantly, unlike results from Fermi function modeling. Magn Reson Med 64:125–137, 2010. © 2010 Wiley‐Liss, Inc.
RT‐GROG: parallelized self‐calibrating GROG for real‐time MRI
Authors: Saybasili Haris , Derbyshire J. Andrew , Kellman Peter , Griswold Mark A. , Ozturk Cengizhan , Lederman Robert J. , Seiberlich Nicole
Published: June 2010

A real‐time implementation of self‐calibrating Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) operator gridding for radial acquisitions is presented. Self‐calibrating GRAPPA operator gridding is a parallel‐imaging‐based, parameter‐free gridding algorithm, where coil sensitivity profiles are used to calculate gridding weights. Self‐calibrating GRAPPA operator gridding's weight‐set calculation and image reconstruction steps are decoupled into two distinct processes, implemented in C++ and parallelized. This decoupling allows the weights to be updated adaptively in the background while image reconstruction threads use the most recent gridding weights to grid and reconstruct images. All possible combinations of two‐dimensional gridding weights GG are evaluated for m,n = {−0.5, −0.4, …, 0, 0.1, …, 0.5} and stored in a look‐up table. Consequently, the per‐sample two‐dimensional weights calculation during gridding is eliminated from the reconstruction process and replaced by a simple look‐up table access. In practice, up to 34× faster reconstruction than conventional (parallelized) self‐calibrating GRAPPA operator gridding is achieved. On a 32‐coil dataset of size 128 × 64, reconstruction performance is 14.5 frames per second (fps), while the data acquisition is 6.6 fps. Magn Reson Med 64:306–312, 2010. © 2010 Wiley‐Liss, Inc.
Three‐dimensional diffusion tensor microimaging for anatomical characterization of the mouse brain
Authors: Aggarwal Manisha , Mori Susumu , Shimogori Tomomi , Blackshaw Seth , Zhang Jiangyang
Published: June 2010

Diffusion tensor imaging is gaining increasing importance for anatomical imaging of the developing mouse brain. However, the application of diffusion tensor imaging to mouse brain imaging at microscopic levels is hindered by the limitation on achievable spatial resolution. In this study, fast diffusion tensor microimaging of the mouse brain, based on a diffusion‐weighted gradient and spin echo technique with twin‐navigator echo phase correction, is presented. Compared to echo planar and spin echo acquisition, the diffusion‐weighted gradient and spin echo acquisition resulted in significant reduction in scan time and had minimal image distortion, thereby allowing acquisition at higher spatial resolution. In this study, three‐dimensional diffusion tensor microimaging of the mouse brains at spatial resolutions of 50‐60 μm revealed unprecedented anatomical details. Thin fiber bundles in the adult striatum and white matter tracts in the embryonic day 12 mouse brains were visualized for the first time. The study demonstrated that data acquired using the diffusion tensor microimaging technique allow three‐dimensional mapping of gene expression data and can serve as a platform to study gene expression patterns in the context of neuroanatomy in the developing mouse brain. Magn Reson Med 64:249–261, 2010. © 2010 Wiley‐Liss, Inc.
Diffusion imaging in humans at 7T using readout‐segmented EPI and GRAPPA
Authors: Heidemann Robin M. , Porter David A. , Anwander Alfred , Feiweier Thorsten , Heberlein Keith , Knösche Thomas R. , Turner Robert
Published: June 2010

Anatomical MRI studies at 7T have demonstrated the ability to provide high‐quality images of human tissue in vivo. However, diffusion‐weighted imaging at 7T is limited by the increased level of artifact associated with standard, single‐shot, echo‐planar imaging, even when parallel imaging techniques such as generalized autocalibrating partially parallel acquisitions (GRAPPA) are used to reduce the effective echo spacing. Readout‐segmented echo‐planar imaging in conjunction with parallel imaging has the potential to reduce these artifacts by allowing a further reduction in effective echo spacing during the echo‐planar imaging readout. This study demonstrates that this approach does indeed provide a substantial improvement in image quality by reducing image blurring and susceptibility‐based distortions, as well as by allowing the acquisition of diffusion‐weighted images with a high spatial resolution. A preliminary application of the technique to high‐resolution diffusion tensor imaging provided a high level of neuroanatomical detail, which should prove valuable in a wide range of applications. Magn Reson Med 64:9–14, 2010. © 2010 Wiley‐Liss, Inc.
Municipal progress under manager government II. Durham gets more and better service
Authors: Dixon Wyatt T.
Published: June 2010

Continuing our series of articles on physical betterments in manager cities.
Solid‐phase extraction of liquiritin and glycyrrhizin from licorice using porous alkyl‐pyridinium polymer sorbent
Authors: Bi Wentao , Tian Minglei , Row Kyung Ho
Published: June 2010

Introduction – Liquiritin and glycyrrhizin are valuable components of licorice. An effective separation and determination procedure is needed to separate the liquiritin and glycyrrhizin from the licorice extract.

Methodology – A polymer‐confined, ionic liquid sorbent was developed using a process involving polymerisation and modification. The obtained porous particles were used as a sorbent in a solid‐phase extraction process to isolate liquiritin and glycyrrhizin from licorice with different washing and elution solvents. The porous alkyl‐pyridinium polymer sorbent was compared with the C18 sorbent.

Results – A simple and convenient method was established to the selectively separate and determinate of liquiritin and glycyrrhizin using a porous ionic liquid‐based polymer coupled with HPLC. Additionally, this study evaluated the application of this sorbent for the detection of these two compounds in commercial medicines.

Conclusion – This method was a viable tool that was compatible with the existing HPLC methods and was used to separate and analyse the content of liquiritin and glycyrrhizin in licorice. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative determination of lanostane triterpenes in Fomes officinalis and their fragmentation study by HPLC‐ESI
Authors: Feng Wei , Yang Junshan , Xu Xudong , Liu Qinghua
Published: June 2010

Introduction – The fruit bodies of Fomes officinalis are used for the treatment of coughs, gastric cancer, rheumatism and hydropsia; however, no method is currently available to assess the quality of this medicinal fungus based on quantitative profile of its main triterpenes.

Objective – To develop a simple and accurate HPLC‐UV method for the simultaneous quantification of five lanostane‐type triterpenes in the fruit bodies of F. officinalis.

Method – Separations were performed on an Agilent Zorbax Eclipse XDB‐C18 column by gradient elution using acetonitrile : formic acid. Analytes were identified by HPLC coupled with electrospray ionisation mass spectrometry experiments. The quantitative HPLC‐UV method was validated for linearity, precision, accuracy and limits of detection and quantification.

Results – Calibration curves presented good linear regression (r > 0.9996) within test ranges. The relative standard deviation of this method was less than 1.7% for intra‐ and inter‐day assays and overall recoveries were 96.4–104.1% for the five compounds analysed. The method was successfully applied to the quantification of five triterpenes in 16 samples of F. officinalis collected from different regions.

Conclusion – The developed assay could be considered as a suitable quality control method for F. officinalis. Copyright © 2010 John Wiley & Sons, Ltd.
Hyperbranched polymer for light‐emitting applications
Authors: Wang Haiqiao , Qiu Teng , Song Na , Li Xiaoyu
Published: June 2010

A light‐emitting partially conjugated hyperbranched polymer (2,5‐dimethoxy‐substituted hyperbranched poly(p‐phenylene vinylene), MOHPV) based on rigid fluorescent conjugated segments, 2,5‐dimethoxy‐substituted distyrylbenzene (a derivative of oligo‐poly(p‐phenylene vinylene)), and flexible non‐conjugated spacers, trioxymethylpropane, was synthesized via an A2 + B3 approach. The weight‐average molecular weight was 2.48 × 104 g mol−1. The introduction of two methoxy groups into central rings of the oligo‐poly(p‐phenylene vinylene) imparted to MOHPV better solubility in common organic solvents and processability than its analogues reported in our previous work, especially the fully conjugated hyperbranched polymers. The effect of the molar ratio of monomer A2 to monomer B3 on the molecular weight and molecular weight distribution was investigated. A single‐layer light‐emitting diode was fabricated employing MOHPV as an emitter. A double‐layer light‐emitting diode was also fabricated by doping an electron transport material, 2‐(4‐biphenylyl)‐5‐phenyl‐1,3,4‐oxadiazole, into the emitting layer and inserting a thin layer of tri(8‐hydroxyquinoline)aluminium as electron‐transporting/hole‐blocking layer. A maximum luminance of 1500 cd m−2 at 12 V and a maximum electroluminescence efficiency of 1.38 cd A−1 at 14 mA cm−3, which are approximately 43.5 and 12.9 times greater, respectively, than those of the single‐layer device, were achieved. The synthetic simplicity, excellent solubility and solution processability, and less of a propensity to aggregation make MOHPV a novel type of emitter for polymer light‐emitting displays. Copyright © 2010 Society of Chemical Industry
The Botrytis cinerea early secretome
Authors: Espino José J. , Gutiérrez‐Sánchez Gerardo , Brito Nélida , Shah Punit , Orlando Ron , González Celedonio
Published: June 2010

The extracellular proteome, or secretome, of phytopathogenic fungi is presumed to be a key element of their infection strategy. Especially interesting constituents of this set are those proteins secreted at the beginning of the infection, during the germination of conidia on the plant surfaces or wounds, since they may play essential roles in the establishment of a successful infection. We have germinated Botrytis cinerea conidia in conditions that resemble the plant environment, a synthetic medium enriched with low molecular weight plant compounds, and we have collected the proteins secreted during the first 16 h by a double precipitation protocol. 2‐D electrophoresis of the precipitated secretome showed a spot pattern similar for all conditions evaluated and for the control medium without plant extract. The proteins in 16 of these spots were identified by PMF and corresponded to 11 different polypeptides. Alternative determination of secretome composition by LC‐MS/MS of tryptic fragments rendered a much larger number, 105 proteins, which included all previously identified by PMF. All proteins were functionally classified according to their putative function in the infection process. Key features of the early secretome include a large number of proteases, the abundance of proteins involved in the degradation of plant defensive barriers, and plenty of proteins with unknown function.
Enhancement through sensitization of VUV‐excited luminescence in red‐emitting pentaborate phosphors
Authors: Mikhailik V. B. , Kraus H.
Published: June 2010

We studied the feasibility of using sensitization for the improvement of the VUV‐to‐visible conversion efficiency of red‐emitting pentaborate phosphor. It is shown that Tb3+ ions that exhibit a strong absorption throughout the 160–230 nm wavelength range facilitate enhancement of Eu3+ emission in TbMgB5O10–Eu at excitation in this spectral range. The maximum increase of the Eu3+ emission efficiency in a pentaborate host at excitation with 150 nm photons is ca.10%. It is also shown that substitution of Zn for Mg in Gd(Mg,Zn)B5O10–Mn phosphor results in strong (up to 2.4 times) enhancement of the intensity of Mn2+ emission. A possible reason for the observed host sensitization effect is discussed.
Some observations of the optical properties of clouds. I: Stratocumulus
Authors: Foot J. S.
Published: June 2010

Aircraft measurements of broad‐band solar irradiances together with radiance measurements in the 1‐2 to 2‐1 μm region are presented for a stratocumulus sheet. Measurements of the solar albedo and cloud physics parameters indicate that the cloud was very uniform and optically thick. Broad‐band observations of albedo agreed well with calculations but observed absorption was about double the model values. Narrow‐band observations of vertical reflectance at three wavelengths suggested a marked increase in effective cloud droplet radius along the cloud, which was not observed. Some evidence that the discrepancy might be due to cloud top unevenness is presented.
A simple model for surface stress and low‐level flow in the tropical atmosphere driven by prescribed heating
Authors: Neelin J. David
Published: June 2010

A simple model is developed for time‐mean, large‐scale flow in the tropical boundary layer forced by vertical velocity at the top of the boundary layer. The model is formulated as an integral over the boundary layer and is closed by assuming the stress to be proportional to the boundary layer mass transport. Since vertical velocity is closely related to diabatic heating in the tropics, the model can also be forced by latent heating as measured by precipitation. In this case, the model can be made equivalent to the widely used Matsuno–Gill model by adding a Newtonian cooling term. This term can be shown to have little effect on the zonally asymmetric component of the flow and, in its absence, the boundary layer flow is decoupled from the flow at upper levels. It is suggested that the success of the Gill model for low‐level flow is due to this effective decoupling. The model is quite successful at simulating GCM results for both the total climatology and El NiTo anomalies. A second model, which takes into account some effects of vertical structure in the boundary layer, is also presented. The zonally symmetric component of the flow is shown to be poorly reproduced in these models.
Retrieval of energy spectra from measured data for assimilation into a wave model
Authors: Thomas J. P.
Published: June 2010

Some results are presented from experiments on modifying modelled wave energy spectra, using reported integrated wave and wind data from three North Sea stations over a six‐month winter period. The resulting spectra are verified against measured spectra from the same stations. Significant improvements are seen in individual cases and in statistical comparisons of spectral parameters over the whole period. Future developments and the problems to be overcome in implementing an operational wave model data assimilation system are discussed.
A comparative study of atmospheric and laboratory‐analogue numerical tornado‐vortex models
Authors: Howells Peter A. C. , Rotunno Richard , Smith Roger K.
Published: June 2010

A detailed sensitivity study of a tornado‐vortex model developed by Howells and Smith is presented in order to draw a comparison between the results of various axisymmetric models that purport to simulate laboratory and tornadic vortices. The model incorporates a stretched finite‐difference mesh in both radial and vertical directions and this provides for an increase in resolution in the vicinity of the vortex core and lower‐boundary layer. The development of the vortex is studied for different values of two key parameters. These are the ratio of the applied tangential velocity to the mean vertical velocity (the swirl ratio) and the Reynolds' number based on the eddy diffusivity coefficient, the mean radial velocity, and the radius of the domain. Most of the simulations are for a no‐slip lower boundary, but a few free‐slip experiments are presented for comparison. These serve to highlight the importance of the radial inflow jet for the no‐slip case.

Emphasis is placed in the no‐slip experiment on the relative importance of the primary meridional circulation associated directly with the applied forcing, and the secondary circulation induced by the lower‐boundary layer. For weak applied swirl (tangential) velocity (1ms−1), the secondary circulation is relatively weak and the maximum tangential velocity is associated with the convergence produced by the primary circulation. Accordingly, this maximum occurs at a substantial height above the lower boundary. For moderate applied swirl velocity (4ms−1), the secondary circulation is manifest as a strong radial inflow jet near the lower boundary. This jet advects rotating air close to the axis. The flow that evolves is dependent on the magnitude of the eddy turbulent diffusivity coefficient. For a relatively low diffusivity coefficient (10m2s−1), a large amplitude centrifugal wave forms and breaks violently near the corner region. At higher values (20m2s−1), a quasi‐steady toroidal vortex develops in the region where the stream surfaces expand, and the maximum swirl velocity is found to occur at low levels near the corner region. This breakdown feature is advected out of the domain when the diffusivity coefficient is increased to 30m2s−1. When the simulations are performed using high imposed swirl velocities (10ms−1), a very intense vortex forms with maximum tangential velocity exceeding 55ms−1, despite the frictional losses near the ground. This is considerably stronger than the equivalent free‐slip vortex which attains a maximum tangential velocity of 44ms−1. Although many of these results have been obtained in past numerical studies, a clear demonstration of the importance of the secondary circulation as compared with the primary circulation has not been forthcoming due to a wide variety of experimental configurations and external parameters.
A line‐by‐line investigation of solar radiative effects in vertically inhomogeneous low clouds
Authors: Ramaswamy V. , Li J.
Published: June 2010

Using a detailed line‐by‐line, multiple‐scattering solar radiative‐transfer model, the influences due to cloud internal inhomogeneity in the vertical upon the solar radiative transfer are investigated. In particular, the consequences due to non‐uniform vertical profiles of liquid water and droplet sizes within low clouds are explored in a systematic manner. The fine structure of the spectral overlap between the water droplet and water vapour optical properties, and its effects upon the radiation absorbed within the cloud layer and that reflected at the top of the cloud, are discussed. Without consideration of the in‐cloud water vapour, a vertically inhomogeneous cloud with properties resembling those observed absorbs more solar radiation than an equivalent homogeneous cloud. However, consideration of the effects of the in‐cloud vapour, while still leading to a slightly greater absorption for the inhomogeneous case, partly offsets the difference introduced by the vertical distribution of the drop microphysics. The vertical distribution of cloud heating rate is changed substantially because of the inhomogeneity in the microphysics, with the heating rate in the top region of the cloud nearly 50% more than that due to an equivalent vertically homogeneous cloud. Vertical inhomogeneity of cloud microphysics has little influence on the broadband solar albedo, but can cause significant decreases of the cloud reflectance at specific near‐infrared wavelengths i.e. wavelengths greater than 1 μm, (equivalently, wave numbers less than 10000 cm−1).
Adjoint sensitivity of an idealized extratropical cyclone with moist physical processes
Authors: Langland Rolf H. , Elsberry Russell L. , Errico Ronald M.
Published: June 2010

An adjoint model (MAMS1) that includes parametrizations for convective (subgrid‐scale), and non‐convective (grid‐scale) precipitation, and surface latent‐heat flux is used to investigate an idealized extratropical cyclogenesis. The adjoint sensitivity information demonstrates the effects that perturbations of model variables and parameters at various times during the cyclone life cycle have on forecast cyclone intensity. For a nonlinear trajectory that includes precipitation processes and surface latent‐heat flux, the accuracy of the tangent‐linear and adjoint model is much higher when moist physical processes are included. Inclusion of moist processes in the adjoint model increases sensitivity magnitude compared with sensitivity obtained with a dry adjoint model, but does not alter the primary spatial pattern of sensitivity.

The larger cyclone deepening rates that occur with the inclusion of moisture are related to latent‐heat release from condensation of water vapour in areas of the middle and lower troposphere (the warm‐front region) that are strongly sensitive to temperature perturbations in both dry and moist cyclone simulations. The effects of diabatic heating on cyclone development are interpreted as a reinforcement of dry baroclinic instability, and not a separate development mechanism (which would have a unique non‐baroclinic sensitivity signature). The sensitivity patterns explain why favourably positioned latent‐heat release is an ingredient that can lead to explosive baroclinic development. Cyclone intensity is very sensitive to the vertical distribution of temperature perturbations, so this feature of diabatic heating is critical to the cyclone forecast.

An increase in the transfer coefficient, CE, for the surface latent‐heat flux can intensify the cyclone by adding moisture to the lower troposphere in the cyclone warm sector before the release of latent heat by precipitation processes. Perturbations of CE have more effect on cyclone intensity than perturbations of the transfer coefficients involved in surface sensible‐heat flux and surface stress during most of the cyclone life cycle.
Resolution of compositional backscattered electron profiles of single interfaces in the scanning electron microscope
Authors: Konkol A.
Published: June 2010

A new method is proposed for the calculation of the lateral resolution of the compositional backscattered electron (BSE) profiles of bulk cross sections of single interfaces in the scanning electron microscope (SEM). The method is based on Niedrig's combined analytical model for electron backscattering and Doig and Flewitt's empirical expression for beam broadening. Experimentally determined lateral resolution values measured on BSE profiles of abrupt interfaces using three different SEMs are very closely reproduced by the calculated values. Based on this new method, the optimum SEM parameters can be determined to enable the measurement of the best resolution BSE profiles with low noise, so that the earlier proposed deconvolution method (Konkol et al. 1994) could be used at optimum conditions.
Real color cathodoluminescence scanning electron microscopy—A new effective method for study of SiC materials and devices
Authors: Saparin G. V. , Mokhov E. N. , Obyden S. K. , Roenkov A. D.
Published: June 2010

Color cathodoluminescence scanning electron microscopy (CCL‐SEM) studies prove the correctness of available information concerning space distribution of luminescence centers in SiC layers. Established facts may be applied for investigation of the polytypism, space distribution of impurities, and native defects induced during growth by high‐energy particles radiation or by diffusion, as well as by the mechanisms of crystal formation. This paper presents a short survey of diagnostic availability of the CCL‐SEM technique for inspection of the SiC materials and devices.
Practical method for noise removal in scanning electron microscopy
Authors: Oho Eisaku , Ichise Norihiko , Martin William H. , Peters Klaus‐Ruediger
Published: June 2010

A new smoothing filter has been developed for noise removal of scanning electron microscopy (SEM) images. We call this the complex hysteresis smoothing (CHS) filter. It is much easier to use for SEM operators than any other conventional smoothing filter, and it rarely produces processing artifacts because it does not utilize a definite mask (which usually has processing parameters of size, shape, weight, and the number of iterations) like a common averaging filter or a complicated filter shape in the Fourier domain. Its criterion for distinguishing noise depends simply on the amplitude of the SEM signal. When applied to several images with different characteristics, it is shown that the present method has a high performance with some original advantages.
Color cathodoluminescence‐scanning electron microscopy study of the 4H‐SiC heteroepitaxial layers grown by sublimation “sandwich method”
Authors: Mokhov E. N. , Roenkov A. D. , Saparin G. V. , Obyden S. K.
Published: June 2010

The color cathodoluminescence scanning electron microscopy (CCL‐SEM) technique was used for the study of the 4H‐SiC epitaxial layers grown by sublimation “sandwich method” on the 6H‐ or 21R substrates. Elements of the BIY group were introduced for polytype transformations. The method makes it possible to control the polytype in thin layers (0.1–2 μam). The effect of supersaturation and the growth rate on 4H polytype formation have been studied. It was shown that the probability of polytype transformation depends on the configuration of the substrate surface. At low supersaturation, 4H polytype nuclei arise predominantly on projected areas of the (0001)C substrate surface, which had no growth centers such as screw dislocations.
Proper acquisition and handling of scanning electron microscopy images using a high‐performance personal computer
Authors: Oho Eisaku , Ichise Norihiko , Ogashiwa Takeshi
Published: June 2010

The modern high‐performance personal computer (PC) has very recently expanded the range of utilization of digital scanning electron microscopy (SEM) images, and the PC will be used increasingly with SEMs. However, the image quality of digital SEM images may be considerably influenced by scanning and digitization conditions. In particular, the effects of the aliasing error peculiar to digital data are often serious in the low‐magnification acquisition (undersampling) of SEM images, and moreover even a high‐magnification image (oversampling) is disturbed by the undersampled noise (a sort of aliasing error). Furthermore, the signal‐to‐noise ratio of a digitized SEM image is closely related to the performance of the analog‐to‐digital converter. To prevent a flood of low‐quality digital images with artifacts by the aliasing and additional noise, we propose a method using very high‐density sampling (scanning). In addition, we will discuss how to handle digital SEM images from the point of view of the sampling and quantization.
Scanning electron microscope design for quantitative multicontrast
Authors: Khursheed A.
Published: June 2010

Conceptual designs of scanning electron microscopes (SEMs) using a time‐of‐flight electron spectrometer are presented. The procedure for making quantitative measurements with such SEMs is shown to be much simpler and versatile than using conventional SEMs. SEMs which use an electron time‐of‐flight spectrometer are able to operate as multicontrast analytical probes, capable of simultaneously quantifying surface topography, voltage, and material type. In addition, it is demonstrated that these SEMs can be designed to have high spatial resolution, good signal‐to‐noise characteristics, and to be of compact table‐top size.
Transmission and double reflection imaging applications with the confocal scanning laser transmission microscope
Authors: Damaskinos S. , Dixon A. E. , Uesaka T.
Published: June 2010

The confocal scanning laser transmission and double‐reflection microscope (CSLTM) has been used in two completely different applications to illustrate some of its unique capabilities. In the first application, the CSLTM was used in reflection and transmission modes to image neurons in a Golgi‐stained specimen. Images that show the advantages of having both modes of operation on the same microscope are presented and discussed. In the second application, the microscope was used in fluorescence to image fibers in paper. The unique property of the CSLTM that enables imaging both the top and the bottom of a specimen was used to image fluorescence emissions from both sides of a sheet of paper, effectively doubling the depth inside the specimen at which one can produce high contrast images.
An all‐digital method for accurate measurements of mechanical deformations
Authors: Amar Najet Ben , Beghdadi Azeddine , De Lesegno Patrick Viaris
Published: June 2010

In this paper, an experimental analysis method based on image treatment techniques for the quantitative evaluation of some polycrystal material deformations is presented. This method has been successfully developed for this purpose by adapting and developing algorithms suitable for the images under study. Details of the whole process as applied to a typical example are described and discussed.
Effects of tip‐sample forces and humidity on the imaging of DNA with a scanning force microscope
Authors: Yang Gouliang , Vesenka James P. , Bustamante Carlos J.
Published: June 2010

We have investigated the effects of tip‐sample forces and relative humidity when using a scanning force microscope (SFM) to image DNA molecules adsorbed on fresh mica. As the force between the tip and the sample increases, the apparent height of the DNA molecules decreases. After being imaged with high forces, the DNA molecules recover partially in their apparent height, indicating that a plastic deformation of the DNA has been induced by the scanning tip. At low humidities, DNA molecules can be imaged with a force up to 150 nN during the scanning without obvious damages. At higher humidities, however, the DNA molecules can be dissected or swept away by the tip even at a tip‐sample force of 30 nN. The net force between the tip and the molecules is the vector sum of several forces, the dominant components of which are the elastic force due to the cantilever bending and the capillary force resulting from the water meniscus formed between the tip and the sample surface. When the relative humidity of the imaging environment is increased, the capillary force becomes stronger.
Some limitations of surface profile reconstruction in scanning electron microscopy
Authors: Czepkowshi T. , Słówko W.
Published: June 2010

This paper is a contribution to development of electron beam profilography based on the so called “shape from shading” technique. A new formula of signal processing in a two detector system has been proposed. The formula en be applied to all the signals showing Lambert's angular distribution. The signal processing may be realized in “real time” in a simple analog processing system. However, an accuracy of the profiles is limited by numerous errors, mainly by shadowing effects. As the shadowing causes disturbances of the signal flow, a proper design of the detection system is necessary to reduce the errors.
An on‐pole‐piece‐tip deflector for high‐resolution, low‐voltage scanning electron microscopes
Authors: Zhao Yan , Khursheed Aniam
Published: June 2010

A proposal to enlarge the field of view of low‐voltage, high‐resolution scanning electron microscopes is presented in this paper. The proposal is based upon mounting primary beam deflectors onto the pole tip of the objective lens. Simulation results show that this compact arrangement of beam deflection should widen the present attainable field of view at probe resolutions < 5 nm by over an order of magnitude.
On superperiodic features on highly oriented pyrolytic graphite
Authors: Feddes B. , Kravchenko I. I. , Seiberling L. E.
Published: June 2010

We present scanning tunneling microscopy (STM) results that show the superstructure on the highly oriented pryrolytic graphite (HOPG) surface. The superlattice appears to be the result of an apparent twist boundary dislocation. The crucial point of the observation is that the superlattice changes simultaneously its constant from 18 to 72 nm when we go around the screw dislocation in the plane perpendicular to the dislocation vector. Based on available models of the graphite surface top layers, we are able to simulate observed STM images. Our STM observation of the superstructure lattice, whose lattice constant varies continuously, gives strong evidence that the superlattice is of Moiré pattern nature, but a correct model can be built only if the graphite electronic structure is taken into consideration.
Monte Carlo simulation of charging effects on linewidth metrology
Authors: Ko Yeong‐Uk , Chung Myung‐Sae , Kim Seung‐Woo
Published: June 2010

Charging effects of scanning electron microscopes on the linewidth metrology of polymethylmethacrylate (PMMA) insulatorpatterns are investigated using Monte Carlo simulation. It is first revealed in detail how the nonunity yield of electron generation in the PMMA target leads to local charge accumulation and affects the image profile of secondary electrons as charging develops. Then the measurement offset due to charging effects is identified for various target patterns of isolated and array types. Finally, it is concluded that the measurement uncertainty caused by the measurement offset exceeds the error budget limit that will be allowed in the linewidth metrology of the next generation of semiconductors.
Evaluation errors with dust measurements of laminar minerals by scanning electron microscope following German guideline VDI 3492
Authors: Hansgeorg Förster  , Doege Thomas
Published: June 2010

A number of seemingly fibrous particles are found by evaluation of dust measurements of the industrial mineral vermiculite in accordance with German Guideline VDI 3492, part 2 for “measurements of inorganic fibrous particles‐ SEM method.” A more thorough investigation based upon an extension of the measuring method proves the nonfibrous morphology of practically all of these particles. The basic idea of this extension is to tilt the filter holder of the electron microscope and to check the exact orientation of the particles on the filter, an examination which is necessary to determine their true length and diameter. The result indicates that only very few fibrous particles actually exist. In the case of vermiculite, these fibrous particles are rolled up and detached flakes called “scrolls.” The systematic error inherent in VDI 3492, part 2, without extension can be quantified in the case of vermiculite to have a factor > 50, that is, fibre counts obtained are more than 50 times too high.
The structure and thermal stability of tungsten‐based contact metallizations to n‐GaN
Authors: Cole M. W. , Ren F. , Pearton S. J.
Published: June 2010

Thermally stable contacts to n‐GaN have been obtained using W and WSi. Low specific contact resistance was achieved for the W metallization with limited reaction between the metal and semiconductor up to 1000°C. The formation of the β‐W2N and W‐N interfacial phases were deemed responsible for the electrical integrity observed at these annealing temperatures. The Wx‐N1‐x interfacial phases functioned as efficient barriers to the outdiffusion of Ga. For WSi, the β‐W2N interfacial phase formation was observed after annealing at 700° and 800°C. This phase also prevented Ga outdiffusion at these elevated temperatures. Optimization of this phase and moderate suppression of interfacial irregularities occurred after annealing at 800°C. This investigation demonstrates that both W and WSi contacts appear to be reasonable contact choices for high‐temperature electronics applications.
Applications of high‐speed confocal imaging techniques in operative dentistry
Authors: Watson Timothy F.
Published: June 2010

All confocal scanning optical microscopes are suitable for making high‐resolution images of many structures in teeth under near normal conditions. If the microscope can operate at high speed, then the number of applications widens considerably. The high‐frame speed of the tandem scanning reflected light microscope (TSM) enables real‐time examination of teeth in vivo, especially when the microscope is configured with a stabilising objective, featuring internal focusing elements. Experimental procedures examined microscopically on extracted teeth can include the cutting of the hard tissues, observation of fluid flow in dentine, the application of adhesives, and the fracturing of adhesive interfaces under load. Undertaking experiments where time is an important function has improved our knowledge of many of the materials/substrate interactions involved in dental operative procedures. Storing images on media other than video tape can be expensive, but reductions in the cost of computer memory is making digitisation and storage of images in real‐time more widely available.