total mean-square atomic: Topics by WorldWideScience.org

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Atomic mean-square displacements and the critical-voltage effect in cubic solid solutions

International Nuclear Information System (INIS)

Shirley, C.G.; Fisher, R.M.

1979-01-01

The critical-voltage phenomena observed in high-voltage electron microscope images of bend contours as well as in corresponding Kikuchi or convergent-beam diffraction patterns provide sensitive methods of determining submicroscopic alloy parameters such as Debye temperatures, short-range order, and atomic scattering factors. Only a very limited number of critical voltages can be observed in metal crystals in the voltage range usually available, 100 to 1200 kV, so that quantitative interpretation of the data must be based on a few-parameter model which incorporates all the pertinent factors. A satisfactory two-parameter model has been developed which can be used to interpret or compute the critical voltages of substitutional solid solutions as functions of composition, temperature and short-range order. In the alloy systems Fe-Cr, Ni-Au, Cu-Au and Cu-Al, sufficient critical voltage data are available to derive the model parameters which pertain to atomic bonding in the lattice. In addition to atomic scattering amplitudes, the critical voltage depends strongly on the atomic mean-square displacements. The static contribution to the mean-square displacements is large in alloys with large atomic-radius disparity, and is especially sensitive to short-range order in f.c.c. solid solutions. Well-defined best estimates for the model parameters are used to predict the critical voltage and its sensitivity to composition, temperature and short-range order for a large number of solid solutions. Systems for which critical-voltage studies may be of considerable interest are indicated. (author)
Neutron diffraction determination of mean-square atomic displacements

International Nuclear Information System (INIS)

Tibballs, J.E.; Feteris, S.M.; Barnea, Z.

1981-01-01

Integrated intensities for Bragg reflection of neutrons from single crystals of the III-V compounds, InAs and GaSb, have been measured at room temperature. The data were collected at two wavelengths, 0.947 A and 1.241 A, in order to establish the adequacy of a correction for moderate to severe anisotropic extinction. Data were also obtained for InAs at four temperatures from 408 K to 933 K. Corrections for thermal diffuse scattering were applied. The results were analysed in the one-particle potential approximation with terms to fourth-order in the atomic displacements u = (u 1 , u 2 , u 3 ). At 296 K, the mean-square components were determined for In, 0.0116(2)A 2 and As, 0.0102 (1)A 2 ; for Ga, 0.0120(3)A 2 and Sb, 0.0107(3)A 2 . The third-order coefficients for InAs are comparable with those for Si and Ge, those for GaSb with those for zinc chalcogenides. Non-harmonic behaviour in InAs is observed below 400 K
Mean-square displacement of atomic complex in titanium carbonitrides TiCxNy

International Nuclear Information System (INIS)

Khidirov, I.; Sultanova, S.Kh.; Mukhtarova, N.N.; Tokhtashev, B.

2004-01-01

Full text: The atomic mean-square displacement (MSD) is one of important characteristics of solids, and one can use it for determination of a number of other characteristics of substances. In this work the MSD of atomic complex were determined for a number of compositions of the cubic titanium carbonitrides TiC x N y using the neutron powder diffraction data. The error of MSD determination was less than 3 %. When determining intensity of diffraction maximum a correction for the thermal diffusion dispersion (TDD) was included in the neutron diffraction patterns. The contribution of TDD in the intensity of diffraction maxima was found to be less than the experiment error (no more than 1,5 %). Such small value of the TDD correction is explained by refractory of materials. The values of MSD in titanium carbonitrides for a number of compositions, determined by the neutron powder diffraction measurements, are given. It is shown, that the dependence of MSD on the concentration (C+N)/Ti has a complex character. With decrease of the total content of metalloids MSD decreases at first, reaching a minimum about concentration (C+N)/Ti≅0.80, and then increases. MSD consists of dynamic and static distortions, where the static distortions in the compounds with variable composition increase with increasing of deviation from stoichiometry. The above anomaly in the dependence of MSD on the total concentration of metalloids, apparently, point to prevalence of dynamic distortions over static ones and to complex character of concentration dependence of interatomic interactions in the titanium carbonitrides. This work was supported by the Supporting Fund for Fundamental Researches of Uzbekistan Academy of Sciences (Grant No. 6-04)
Nuclear moments and isotopic variation of the mean square charge radii of strontium nuclei by atomic beam laser spectroscopy

International Nuclear Information System (INIS)

Chongkum, S.

1987-10-01

Hyperfine structure and optical isotope shift measurements have been performed on a series of stable and radioactive strontium isotopes (A = 80 to 90), including two isomers 85m and 87m. The spectroscopy applied continuous wave dye laser induced fluorescence of free atoms at λ=293.2 nm in a well collimated atomic beam. The 293.2 nm ultraviolet light was generated by frequency doubling the output of a dye laser in either a temperature tuned Ammonium Dihydrogen Arsenate (ADA) crystal or an angle tuned Lithium Iodate crystal. A special radio frequency (rf) technique was used to tune the dye laser frequency with long term stability. Radioactive Sr isotopes were produced either by neutron capture of stable strontium or by (α,xn) reactions from krypton gas. The samples were purified by an electromagnetic mass separator and their sizes were of order 100 pg, which corresponds to 10 11 atoms. The observed results of the hyperfine structure components are evaluated in terms of nuclear magnetic dipole moments and electric quadrupole moments. Changes in mean square charge radii of strontium nuclei which were extracted from the isotope shift measurements, exhibit a distinct shell effect at the neutron magic number N=50. The experimental data are analysed and compared with some theoretical nuclear model predictions. The strong increase of the nuclear charge radii with decreasing neutron number of isotopes below N=50 is in agreement with the variation of the mean square deformation extracted from measured B(E2) values. (orig.) [de
Approximate calculation method for integral of mean square value of nonstationary response

International Nuclear Information System (INIS)

Aoki, Shigeru; Fukano, Azusa

2010-01-01

The response of the structure subjected to nonstationary random vibration such as earthquake excitation is nonstationary random vibration. Calculating method for statistical characteristics of such a response is complicated. Mean square value of the response is usually used to evaluate random response. Integral of mean square value of the response corresponds to total energy of the response. In this paper, a simplified calculation method to obtain integral of mean square value of the response is proposed. As input excitation, nonstationary white noise and nonstationary filtered white noise are used. Integrals of mean square value of the response are calculated for various values of parameters. It is found that the proposed method gives exact value of integral of mean square value of the response.
Neutron diffraction determination of atomic mean-square displacements in cubic compounds of Ni-Al and Ni-Al-Cu systems

International Nuclear Information System (INIS)

Khidirov, I.; Mukhtarova, N.N.

2002-01-01

The atomic mean-square displacements (AMSD) are some of important characteristics of the solid and can be the main information for determination of a number of other characteristics of substances. In the work AMSD is determined for a number of cubic compounds of Ni-Al, Ni-Al-Cu systems immediately from intensities of neutron diffraction maxima. It is shown by the offered method that in all NiAl x and NiAlCu x compounds with the CsCl - type structure AMSD are near each other and they are practically constant. Therefore it is possible to assume that within the homogeneity region of these compounds the interatomic bond forces are changed insignificantly
Quantized kernel least mean square algorithm.

Science.gov (United States)

Chen, Badong; Zhao, Songlin; Zhu, Pingping; Príncipe, José C

2012-01-01

In this paper, we propose a quantization approach, as an alternative of sparsification, to curb the growth of the radial basis function structure in kernel adaptive filtering. The basic idea behind this method is to quantize and hence compress the input (or feature) space. Different from sparsification, the new approach uses the "redundant" data to update the coefficient of the closest center. In particular, a quantized kernel least mean square (QKLMS) algorithm is developed, which is based on a simple online vector quantization method. The analytical study of the mean square convergence has been carried out. The energy conservation relation for QKLMS is established, and on this basis we arrive at a sufficient condition for mean square convergence, and a lower and upper bound on the theoretical value of the steady-state excess mean square error. Static function estimation and short-term chaotic time-series prediction examples are presented to demonstrate the excellent performance.
Variation of the mean square amplitude with concentration in Hg1-xCdxTe

International Nuclear Information System (INIS)

Sadaiyandi, K.; Ramachandran, K.

1989-01-01

The mean square displacements (MSD) of Hg and Te in the mixed system Hg 1-x Cd x Te have been calculated for various concentrations of Cd atoms (x = 0.20, 0.40, 0.60, 0.80, 1.00) at 4, 77, and 300 K by means of the virtual crystal approximation. An unusual trend in MSD is found for x below 0.2: the higher mass has higher value of MS amplitude
Mean square stabilization and mean square exponential stabilization of stochastic BAM neural networks with Markovian jumping parameters

International Nuclear Information System (INIS)

Ye, Zhiyong; Zhang, He; Zhang, Hongyu; Zhang, Hua; Lu, Guichen

2015-01-01

Highlights: •This paper introduces a non-conservative Lyapunov functional. •The achieved results impose non-conservative and can be widely used. •The conditions are easily checked by the Matlab LMI Tool Box. The desired state feedback controller can be well represented by the conditions. -- Abstract: This paper addresses the mean square exponential stabilization problem of stochastic bidirectional associative memory (BAM) neural networks with Markovian jumping parameters and time-varying delays. By establishing a proper Lyapunov–Krasovskii functional and combining with LMIs technique, several sufficient conditions are derived for ensuring exponential stabilization in the mean square sense of such stochastic BAM neural networks. In addition, the achieved results are not difficult to verify for determining the mean square exponential stabilization of delayed BAM neural networks with Markovian jumping parameters and impose less restrictive and less conservative than the ones in previous papers. Finally, numerical results are given to show the effectiveness and applicability of the achieved results
Deformation analysis with Total Least Squares

Directory of Open Access Journals (Sweden)

M. Acar

2006-01-01

Full Text Available Deformation analysis is one of the main research fields in geodesy. Deformation analysis process comprises measurement and analysis phases. Measurements can be collected using several techniques. The output of the evaluation of the measurements is mainly point positions. In the deformation analysis phase, the coordinate changes in the point positions are investigated. Several models or approaches can be employed for the analysis. One approach is based on a Helmert or similarity coordinate transformation where the displacements and the respective covariance matrix are transformed into a unique datum. Traditionally a Least Squares (LS technique is used for the transformation procedure. Another approach that could be introduced as an alternative methodology is the Total Least Squares (TLS that is considerably a new approach in geodetic applications. In this study, in order to determine point displacements, 3-D coordinate transformations based on the Helmert transformation model were carried out individually by the Least Squares (LS and the Total Least Squares (TLS, respectively. The data used in this study was collected by GPS technique in a landslide area located nearby Istanbul. The results obtained from these two approaches have been compared.
A Newton Algorithm for Multivariate Total Least Squares Problems

Directory of Open Access Journals (Sweden)

WANG Leyang

2016-04-01

Full Text Available In order to improve calculation efficiency of parameter estimation, an algorithm for multivariate weighted total least squares adjustment based on Newton method is derived. The relationship between the solution of this algorithm and that of multivariate weighted total least squares adjustment based on Lagrange multipliers method is analyzed. According to propagation of cofactor, 16 computational formulae of cofactor matrices of multivariate total least squares adjustment are also listed. The new algorithm could solve adjustment problems containing correlation between observation matrix and coefficient matrix. And it can also deal with their stochastic elements and deterministic elements with only one cofactor matrix. The results illustrate that the Newton algorithm for multivariate total least squares problems could be practiced and have higher convergence rate.
Proportionate-type normalized last mean square algorithms

CERN Document Server

Wagner, Kevin

2013-01-01

The topic of this book is proportionate-type normalized least mean squares (PtNLMS) adaptive filtering algorithms, which attempt to estimate an unknown impulse response by adaptively giving gains proportionate to an estimate of the impulse response and the current measured error. These algorithms offer low computational complexity and fast convergence times for sparse impulse responses in network and acoustic echo cancellation applications. New PtNLMS algorithms are developed by choosing gains that optimize user-defined criteria, such as mean square error, at all times. PtNLMS algorithms ar
On root mean square approximation by exponential functions

OpenAIRE

Sharipov, Ruslan

2014-01-01

The problem of root mean square approximation of a square integrable function by finite linear combinations of exponential functions is considered. It is subdivided into linear and nonlinear parts. The linear approximation problem is solved. Then the nonlinear problem is studied in some particular example.
The mean squared writhe of alternating random knot diagrams

Energy Technology Data Exchange (ETDEWEB)

Diao, Y; Hinson, K [Department of Mathematics and Statistics University of North Carolina at Charlotte, NC 28223 (United States); Ernst, C; Ziegler, U, E-mail: ydiao@uncc.ed [Department of Mathematics and Computer Science, Western Kentucky University, Bowling Green, KY 42101 (United States)

2010-12-10

The writhe of a knot diagram is a simple geometric measure of the complexity of the knot diagram. It plays an important role not only in knot theory itself, but also in various applications of knot theory to fields such as molecular biology and polymer physics. The mean squared writhe of any sample of knot diagrams with n crossings is n when for each diagram at each crossing one of the two strands is chosen as the overpass at random with probability one-half. However, such a diagram is usually not minimal. If we restrict ourselves to a minimal knot diagram, then the choice of which strand is the over- or under-strand at each crossing is no longer independent of the neighboring crossings and a larger mean squared writhe is expected for minimal diagrams. This paper explores the effect on the correlation between the mean squared writhe and the diagrams imposed by the condition that diagrams are minimal by studying the writhe of classes of reduced, alternating knot diagrams. We demonstrate that the behavior of the mean squared writhe heavily depends on the underlying space of diagram templates. In particular this is true when the sample space contains only diagrams of a special structure. When the sample space is large enough to contain not only diagrams of a special type, then the mean squared writhe for n crossing diagrams tends to grow linearly with n, but at a faster rate than n, indicating an intrinsic property of alternating knot diagrams. Studying the mean squared writhe of alternating random knot diagrams also provides some insight into the properties of the diagram generating methods used, which is an important area of study in the applications of random knot theory.
Plasmon excitations in doped square-lattice atomic clusters

Science.gov (United States)

Wang, Yaxin; Yu, Ya-Bin

2017-12-01

Employing the tight-binding model, we theoretically study the properties of the plasmon excitations in doped square-lattice atomic clusters. The results show that the dopant atoms would blur the absorption spectra, and give rise to extra plasmon resonant peaks as reported in the literature; however, our calculated external-field induced oscillating charge density shows that no obvious evidences indicate the so-called local mode of plasmon appearing in two-dimensional-doped atomic clusters, but the dopants may change the symmetry of the charge distribution. Furthermore, we show that the disorder of the energy level due to dopant makes the absorption spectrum has a red- or blue-shift, which depends on the position of impurities; disorder of hopping due to dopant makes a blue- or red-shift, a larger (smaller) hopping gives a blue-shift (red-shift); and a larger (smaller) host-dopant and dopant-dopant intersite coulomb repulsion induces a blue-shift (red-shift).
Application of the Polynomial-Based Least Squares and Total Least Squares Models for the Attenuated Total Reflection Fourier Transform Infrared Spectra of Binary Mixtures of Hydroxyl Compounds.

Science.gov (United States)

Shan, Peng; Peng, Silong; Zhao, Yuhui; Tang, Liang

2016-03-01

An analysis of binary mixtures of hydroxyl compound by Attenuated Total Reflection Fourier transform infrared spectroscopy (ATR FT-IR) and classical least squares (CLS) yield large model error due to the presence of unmodeled components such as H-bonded components. To accommodate these spectral variations, polynomial-based least squares (LSP) and polynomial-based total least squares (TLSP) are proposed to capture the nonlinear absorbance-concentration relationship. LSP is based on assuming that only absorbance noise exists; while TLSP takes both absorbance noise and concentration noise into consideration. In addition, based on different solving strategy, two optimization algorithms (limited-memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) algorithm and Levenberg-Marquardt (LM) algorithm) are combined with TLSP and then two different TLSP versions (termed as TLSP-LBFGS and TLSP-LM) are formed. The optimum order of each nonlinear model is determined by cross-validation. Comparison and analyses of the four models are made from two aspects: absorbance prediction and concentration prediction. The results for water-ethanol solution and ethanol-ethyl lactate solution show that LSP, TLSP-LBFGS, and TLSP-LM can, for both absorbance prediction and concentration prediction, obtain smaller root mean square error of prediction than CLS. Additionally, they can also greatly enhance the accuracy of estimated pure component spectra. However, from the view of concentration prediction, the Wilcoxon signed rank test shows that there is no statistically significant difference between each nonlinear model and CLS. © The Author(s) 2016.
A cellular automata simulation study of surface roughening resulting from multi-atom etch pit generation during sputtering

Energy Technology Data Exchange (ETDEWEB)

Toh, Y S; Nobes, M J; Carter, G [Dept. of Electronic and Electrical Engineering, Univ. of Salford (United Kingdom)

1992-04-01

A two-dimensional square matrix of pseudo-atomic positions is erected and atom removal from the ''surface'' is effected randomly. Either single atoms or groups of atoms (to simulate multi-atom pit generation) are removed. The characteristics of the evolving roughened, terraced ''surface'' are evaluated as a function of the total number of atoms, or equivalent numbers of atomic layers, removed. These characteristics include the ''mean'' position of the sputtered surface, the standard deviation of terrace length about the mean and the form of the terrace length distributions. The results of the single-atom removal mode compare exactly with theoretical predictions in that, for large numbers of atoms removed the depth position of the mean of the terrace length distribution is identical to the mean sputtered depth and the standard deviation increases as the square root of this depth. For multi-atom removal modes (which cannot be predicted theoretically) the standard deviation also increases as the square root of the mean sputtered depth but with a larger proportionality constant. The implications of these observations for the evolution of surface morphology during high yield sputtering is discussed. (orig.).
Diffuse versus square-well confining potentials in modelling A-C60 atoms

International Nuclear Information System (INIS)

Dolmatov, V K; King, J L; Oglesby, J C

2012-01-01

A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C 60 cage potential in calculations of endohedral atoms A-C 60 , by a more realistic diffuse potential is explored. The photoionization of endohedral H-C 60 and Xe-C 60 is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of A-C 60 atoms are largely insensitive to the degree η of diffuseness of the potential borders, in a reasonably broad range of ηs. These spectra are found to be insensitive to discontinuity of the square-well potential as well. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for A-C 60 spectra, are recommended for future studies. (paper)
Regularization by truncated total least squares

DEFF Research Database (Denmark)

Hansen, Per Christian; Fierro, R.D; Golub, G.H

1997-01-01

The total least squares (TLS) method is a successful method for noise reduction in linear least squares problems in a number of applications. The TLS method is suited to problems in which both the coefficient matrix and the right-hand side are not precisely known. This paper focuses on the use...... schemes for relativistic hydrodynamical equations. Such an approximate Riemann solver is presented in this paper which treats all waves emanating from an initial discontinuity as themselves discontinuous. Therefore, jump conditions for shocks are approximately used for rarefaction waves. The solver...... is easy to implement in a Godunov scheme and converges rapidly for relativistic hydrodynamics. The fast convergence of the solver indicates the potential of a higher performance of a Godunov scheme in which the solver is used....
Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

CERN Multimedia

2002-01-01

The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

Calculation of the mean-square velocities of atom oscillations in the Moessbauer experiment

International Nuclear Information System (INIS)

Semenov, Ya.S.; Lebedev, M.P.

2005-01-01

To study mechanical and physical properties of solid bodies, it is important to know the behavior of rms velocities of atomic oscillations. Binary iron alloys in the vicinity of phase transition temperatures were investigated using the Moessbauer spectroscopy. The rms velocities of atomic oscillations demonstrate that 3d-3p direct chemical bonds for Si and 3d-4p direct chemical bonds for Ge are broken (formed) at the phase transition temperature; as a consequence, the velocities of atomic oscillations increase abruptly [ru
Nuclear moments and the change of the mean square charge radius of neutron deficient thallium isotopes

International Nuclear Information System (INIS)

Menges, R.; Dinger, U.; Boos, N.; Huber, G.; Schroeder, S.

1992-01-01

The hyperfine structure, isotope and isomeric shifts in the atomic transition 6p 2 P 3/2 -7s 2 S 1/2 , λ=535 nm have been measured for the I=7 and I=2 states of 190,192,194,196 Tl, the I=1/2 and I=9/2 states of 191 Tl and the I=7 isomer of 188 Tl. The thallium isotopes were prepared as fast atomic beams at the GSI on-line mass separator following fusion reactions and - in some cases - subsequent β-decay. The nuclear dipole moments, electric quadrupole moments and the change in the nuclear mean square charge radius are evaluated. The uu-isotopes show an isomeric shift which changes sign between 192 Tl and 194 Tl. (orig.)
Prediction on long-term mean and mean square pollutant concentrations in an urban atmosphere

Energy Technology Data Exchange (ETDEWEB)

Kumar, S; Lamb, R G; Seinfeld, J H

1976-01-01

The general problem of predicting long-term average (say yearly) pollutant concentrations in an urban atmosphere is formulated. The pollutant concentration can be viewed as a random process, the complete description of which requires knowledge of its probability density function, which is unknown. The mean concentration is the first moment of the concentration distribution, and at present there exist a number of models for predicting the long-term mean concentration of an inert pollutant. The second moment, or mean square concentration, indicates additional features of the distribution, such as the level of fluctuations about the mean. In the paper a model proposed by Lamb for the long-term mean concentration is reviewed, and a new model for prediction of the long-term mean square concentration of an inert air pollutant is derived. The properties and uses of the model are discussed, and the equations defining the model are presented in a form for direct application to an urban area.
Mean Square Synchronization of Stochastic Nonlinear Delayed Coupled Complex Networks

Directory of Open Access Journals (Sweden)

Chengrong Xie

2013-01-01

Full Text Available We investigate the problem of adaptive mean square synchronization for nonlinear delayed coupled complex networks with stochastic perturbation. Based on the LaSalle invariance principle and the properties of the Weiner process, the controller and adaptive laws are designed to ensure achieving stochastic synchronization and topology identification of complex networks. Sufficient conditions are given to ensure the complex networks to be mean square synchronization. Furthermore, numerical simulations are also given to demonstrate the effectiveness of the proposed scheme.
Calculation of the mean scattering angle, the logarithmic decrement and its mean square

International Nuclear Information System (INIS)

Bersillon, O.; Caput, B.

1984-06-01

The calculation of the mean scattering angle, the logarithmic decrement and its mean square, starting from the Legendre polynomial expansion coefficients of the relevant elastic scattering angular distribution, is numerically studied with different methods, one of which is proposed for the usual determination of these quantities which are present in the evaluated data files ENDF [fr
Simplified neural networks for solving linear least squares and total least squares problems in real time.

Science.gov (United States)

Cichocki, A; Unbehauen, R

1994-01-01

In this paper a new class of simplified low-cost analog artificial neural networks with on chip adaptive learning algorithms are proposed for solving linear systems of algebraic equations in real time. The proposed learning algorithms for linear least squares (LS), total least squares (TLS) and data least squares (DLS) problems can be considered as modifications and extensions of well known algorithms: the row-action projection-Kaczmarz algorithm and/or the LMS (Adaline) Widrow-Hoff algorithms. The algorithms can be applied to any problem which can be formulated as a linear regression problem. The correctness and high performance of the proposed neural networks are illustrated by extensive computer simulation results.
Total least squares for anomalous change detection

Science.gov (United States)

Theiler, James; Matsekh, Anna M.

2010-04-01

A family of subtraction-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQbased anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and special cases of it are equivalent to canonical correlation analysis and optimized covariance equalization. What whitened TLSQ offers is a generalization of these algorithms with the potential for better performance.
Newton-Gauss Algorithm of Robust Weighted Total Least Squares Model

Directory of Open Access Journals (Sweden)

WANG Bin

2015-06-01

Full Text Available Based on the Newton-Gauss iterative algorithm of weighted total least squares (WTLS, a robust WTLS (RWTLS model is presented. The model utilizes the standardized residuals to construct the weight factor function and the square root of the variance component estimator with robustness is obtained by introducing the median method. Therefore, the robustness in both the observation and structure spaces can be simultaneously achieved. To obtain standardized residuals, the linearly approximate cofactor propagation law is employed to derive the expression of the cofactor matrix of WTLS residuals. The iterative calculation steps for RWTLS are also described. The experiment indicates that the model proposed in this paper exhibits satisfactory robustness for gross errors handling problem of WTLS, the obtained parameters have no significant difference with the results of WTLS without gross errors. Therefore, it is superior to the robust weighted total least squares model directly constructed with residuals.
Least-mean-square spatial filter for IR sensors.

Science.gov (United States)

Takken, E H; Friedman, D; Milton, A F; Nitzberg, R

1979-12-15

A new least-mean-square filter is defined for signal-detection problems. The technique is proposed for scanning IR surveillance systems operating in poorly characterized but primarily low-frequency clutter interference. Near-optimal detection of point-source targets is predicted both for continuous-time and sampled-data systems.
Cold atoms at unitarity and inverse square interaction

Energy Technology Data Exchange (ETDEWEB)

Bhaduri, R K [Department of Physics and Astronomy, McMaster University, Hamilton L8S 4M1 (Canada); Murthy, M V N [The Institute of Mathematical Sciences, Chennai 600113 (India); Srivastava, M K [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India)

2009-12-14

Consider two identical atoms in a spherical harmonic oscillator interacting with a zero-range interaction which is tuned to produce an s-wave zero-energy bound state. The quantum spectrum of the system is known to be exactly solvable. We note that the same partial wave quantum spectrum is obtained by the one-dimensional scale-invariant inverse square potential. Long known as the Calogero-Sutherland-Moser (CSM) model, it leads to the fractional exclusion statistics (FES) of Haldane and Wu. The statistical parameter is deduced from the analytically calculated second virial coefficient. When FES is applied to a Fermi gas at unitarity, it gives good agreement with experimental data without the use of any free parameter.
Total quality approach at ABB Atom Nuclear Fuel - winner of the Swedish quality award 1994

International Nuclear Information System (INIS)

Moorlin, K.; Olsson, S.

1995-01-01

ABB Atom Nuclear Fuel Division received the Swedish Quality Award 1994. The company has since many years a reputation for high product quality and a well implemented quality assurance system. Since some years a total quality approach is applied. For ABB Atom, total quality means continuous improvement of all business processes keeping the customer in focus. This paper elaborates on the improvement tools used at the ABB Atom Nuclear Fuel Division and gives some detailed information of the experience. (author) 6 figs
Moments and mean square charge radii of short-lived argon isotopes

CERN Document Server

Klein, A; Georg, U; Keim, M; Lievens, P; Neugart, R; Neuroth, M; Silverans, R E; Vermeeren, L

1996-01-01

We report on the measurement of optical isotope shifts for $^{32-40}$Ar and for $^{46}$Ar from which the changes in mean square nuclear charge radii across the N = 20 neutron shell closure are deducted. The investigations were carried out by collinear laser spectroscopy in fast beams of neutral argon atoms. The ultra-sensitive detection combines optical pumping, state-selective collisional ionization and counting of $\\beta$-radioactivity. By reaching far into the sd-shell, the results add new information to the systematics of radii in the calcium region (Z $\\approx$ 20). Contrary to all major neutron shell closures with N $\\geq$ 28, the N = 20 shell closure causes no significant slope change in the development of the radii. Information from the hyperfine structure of the odd-A isotopes includes includes the magnetic moments of $^{33}$Ar (I=1/2) and $^{39}$Ar (I=7/2), and the quadrupole moments of $^{35}$Ar, $^{37}$Ar (I=3/2) and $^{39}$Ar. The electromagnetic moments are compared to shell-model predictions fo...
Mean Square Exponential Stability of Stochastic Switched System with Interval Time-Varying Delays

Directory of Open Access Journals (Sweden)

Manlika Rajchakit

2012-01-01

Full Text Available This paper is concerned with mean square exponential stability of switched stochastic system with interval time-varying delays. The time delay is any continuous function belonging to a given interval, but not necessary to be differentiable. By constructing a suitable augmented Lyapunov-Krasovskii functional combined with Leibniz-Newton’s formula, a switching rule for the mean square exponential stability of switched stochastic system with interval time-varying delays and new delay-dependent sufficient conditions for the mean square exponential stability of the switched stochastic system are first established in terms of LMIs. Numerical example is given to show the effectiveness of the obtained result.
Study of confined many electron atoms by means of the POEP method

International Nuclear Information System (INIS)

Sarsa, A; Buendía, E; Gálvez, F J

2014-01-01

The electronic structure of confined atoms under impenetrable spherical walls is studied by means of the parameterized optimized effective potential method. A cut-off factor is employed to account for Dirichlet boundary conditions. Two atomic basis sets commonly used for describing free atoms have been analyzed within this scheme. The accuracy of the method is similar to that achieved for the free atoms. The ground state electrostatic multiplet of the carbon atom as well as the ground state and both the [Ar]4s3d 7 5 F and [Ar]3d 8 3 F excited states of the iron atom are studied. The behaviour of the energy levels with the confinement has been analyzed in terms of the different contributions to the total energy of the atom. For the iron atom, the effect of confinement on the outermost orbitals is studied. (paper)
Table of nuclear root mean square charge radii. Summary

International Nuclear Information System (INIS)

Paviotti-Corcuera, R.; McLaughlin, P.K.

1999-01-01

This document describes a table of nuclear root-mean-square (rms) charge radii evaluated by two different procedures. The data are available from the IAEA Nuclear Data Section via INTERNET or on PC diskettes upon request. This document supersedes the previous IAEA-NDS-163, 1990, 'Nuclear Charge Radii'. (author)
An on-line modified least-mean-square algorithm for training neurofuzzy controllers.

Science.gov (United States)

Tan, Woei Wan

2007-04-01

The problem hindering the use of data-driven modelling methods for training controllers on-line is the lack of control over the amount by which the plant is excited. As the operating schedule determines the information available on-line, the knowledge of the process may degrade if the setpoint remains constant for an extended period. This paper proposes an identification algorithm that alleviates "learning interference" by incorporating fuzzy theory into the normalized least-mean-square update rule. The ability of the proposed methodology to achieve faster learning is examined by employing the algorithm to train a neurofuzzy feedforward controller for controlling a liquid level process. Since the proposed identification strategy has similarities with the normalized least-mean-square update rule and the recursive least-square estimator, the on-line learning rates of these algorithms are also compared.
Estimasi Kanal Akustik Bawah Air Untuk Perairan Dangkal Menggunakan Metode Least Square (LS dan Minimum Mean Square Error (MMSE

Directory of Open Access Journals (Sweden)

Mardawia M Panrereng

2015-06-01

Full Text Available Dalam beberapa tahun terakhir, sistem komunikasi akustik bawah air banyak dikembangkan oleh beberapa peneliti. Besarnya tantangan yang dihadapi membuat para peneliti semakin tertarik untuk mengembangkan penelitian dibidang ini. Kanal bawah air merupakan media komunikasi yang sulit karena adanya attenuasi, absorption, dan multipath yang disebabkan oleh gerakan gelombang air setiap saat. Untuk perairan dangkal, multipath disebabkan adanya pantulan dari permukaan dan dasar laut. Kebutuhan pengiriman data cepat dengan bandwidth terbatas menjadikan Ortogonal Frequency Division Multiplexing (OFDM sebagai solusi untuk komunikasi transmisi tinggi dengan modulasi menggunakan Binary Phase-Shift Keying (BPSK. Estimasi kanal bertujuan untuk mengetahui karakteristik respon impuls kanal propagasi dengan mengirimkan pilot simbol. Pada estimasi kanal menggunakan metode Least Square (LS nilai Mean Square Error (MSE yang diperoleh cenderung lebih besar dari metode estimasi kanal menggunakan metode Minimum Mean Square (MMSE. Hasil kinerja estimasi kanal berdasarkan perhitungan Bit Error Rate (BER untuk estimasi kanal menggunakan metode LS dan metode MMSE tidak menunjukkan perbedaan yang signifikan yaitu berselisih satu SNR untuk setiap metode estimasi kanal yang digunakan.
Total cross section for relativistic positronium interaction with atom

International Nuclear Information System (INIS)

Pak, A.S.; Tarasov, A.V.

1985-01-01

Total cross sections of interaction of positronium relativistic atoms with atoms are calculated. Calculations are conducted within the framework of potential theory in Born approximaton. Contributions in total cross section of coherent (σsub(coh)) and incoherent (σsub(inc)) parts are analyzed. It is shown that for light elements σsub(inc) value is comparable with σsub(coh), and for heavy ones the ratio σsub(inc)/σsub(coh) sufficiently exceeds Zsup(-1) (Z-charge of the atomic nucleus. Numerical calculation results are presented. A conclusion is made on importance of the coherent part account during the calculation of total cross sections
Universal time-dependence of the mean-square displacement in extremely rugged energy landscapes with equal minima

DEFF Research Database (Denmark)

Dyre, Jeppe; Jacobsen, Jacob M.

1995-01-01

This paper presents a calculation of the time dependence of the mean-square displacement for symmetric random energy barrier hopping models at low temperatures, where the frequency dependence of the normalized diffusion constant D-tilde becomes universal, i.e., independent of the energy barrier...... probability distribution [J. C. Dyre, Phys. Rev. B 49, 11 709 (1994)]. The universal time dependence of the mean-square displacement is calculated from the effective medium approximation (EMA) universality equation, D-tilde lnD-tilde=s-tilde, where s-tilde is the dimensionless imaginary frequency, as well...... as for the approximation to the EMA universality equation D-tilde~=s-tilde/ln(1+s-tilde). At long times the universal mean-square displacement is linear in time, corresponding to ordinary diffusion, whereas the mean-square displacement at short times t in dimensionless units varies as 2/ln(t-1)....
Self-Regular Black Holes Quantized by means of an Analogue to Hydrogen Atoms

CERN Document Server

Liu, Chang; Wu, Yu-Mei; Zhang, Yu-Hao

2016-01-01

We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.

Some Results on Mean Square Error for Factor Score Prediction

Science.gov (United States)

Krijnen, Wim P.

2006-01-01

For the confirmatory factor model a series of inequalities is given with respect to the mean square error (MSE) of three main factor score predictors. The eigenvalues of these MSE matrices are a monotonic function of the eigenvalues of the matrix gamma[subscript rho] = theta[superscript 1/2] lambda[subscript rho] 'psi[subscript rho] [superscript…
Positron total scattering cross-sections for alkali atoms

Science.gov (United States)

Sinha, Nidhi; Singh, Suvam; Antony, Bobby

2018-01-01

Positron-impact total scattering cross-sections for Li, Na, K, Rb, Cs and Fr atoms are calculated in the energy range from 5-5000 eV employing modified spherical complex optical potential formalism. The main aim of this work is to apply this formalism to the less studied positron-target collision systems. The results are compared with previous theoretical and experimental data, wherever available. In general, the present data show overall agreement and consistency with other results. Furthermore, we have done a comparative study of the results to investigate the effect of atomic size on the cross-sections as we descend through the group in the periodic table. We have also plotted a correlation graph of the present total cross-sections with polarizability and number of target electrons. The two correlation plots confirm the credibility and consistency of the present results. Besides, this is the first theoretical attempt to report positron-impact total cross-sections of alkali atoms over such a wide energy range.
Mean square exponential stability of stochastic delayed Hopfield neural networks

International Nuclear Information System (INIS)

Wan Li; Sun Jianhua

2005-01-01

Stochastic effects to the stability property of Hopfield neural networks (HNN) with discrete and continuously distributed delay are considered. By using the method of variation parameter, inequality technique and stochastic analysis, the sufficient conditions to guarantee the mean square exponential stability of an equilibrium solution are given. Two examples are also given to demonstrate our results
Mean-square performance of a convex combination of two adaptive filters

DEFF Research Database (Denmark)

Garcia, Jeronimo; Figueiras-Vidal, A.R.; Sayed, A.H.

2006-01-01

Combination approaches provide an interesting way to improve adaptive filter performance. In this paper, we study the mean-square performance of a convex combination of two transversal filters. The individual filters are independently adapted using their own error signals, while the combination i...
Adaptive Noise Canceling Menggunakan Algoritma Least Mean Square (Lms)

OpenAIRE

Nardiana, Anita; Sumaryono, Sari Sujoko

2011-01-01

Noise is inevitable in communication system. In some cases, noise can disturb signal. It is veryannoying as the received signal is jumbled with the noise itself. To reduce or remove noise, filter lowpass,highpass or bandpass can solve the problems, but this method cannot reach a maximum standard. One ofthe alternatives to solve the problem is by using adaptive filter. Adaptive algorithm frequently used is LeastMean Square (LMS) Algorithm which is compatible to Finite Impulse Response (FIR). T...
Study of the convergence behavior of the complex kernel least mean square algorithm.

Science.gov (United States)

Paul, Thomas K; Ogunfunmi, Tokunbo

2013-09-01

The complex kernel least mean square (CKLMS) algorithm is recently derived and allows for online kernel adaptive learning for complex data. Kernel adaptive methods can be used in finding solutions for neural network and machine learning applications. The derivation of CKLMS involved the development of a modified Wirtinger calculus for Hilbert spaces to obtain the cost function gradient. We analyze the convergence of the CKLMS with different kernel forms for complex data. The expressions obtained enable us to generate theory-predicted mean-square error curves considering the circularity of the complex input signals and their effect on nonlinear learning. Simulations are used for verifying the analysis results.
Block Least Mean Squares Algorithm over Distributed Wireless Sensor Network

Directory of Open Access Journals (Sweden)

T. Panigrahi

2012-01-01

Full Text Available In a distributed parameter estimation problem, during each sampling instant, a typical sensor node communicates its estimate either by the diffusion algorithm or by the incremental algorithm. Both these conventional distributed algorithms involve significant communication overheads and, consequently, defeat the basic purpose of wireless sensor networks. In the present paper, we therefore propose two new distributed algorithms, namely, block diffusion least mean square (BDLMS and block incremental least mean square (BILMS by extending the concept of block adaptive filtering techniques to the distributed adaptation scenario. The performance analysis of the proposed BDLMS and BILMS algorithms has been carried out and found to have similar performances to those offered by conventional diffusion LMS and incremental LMS algorithms, respectively. The convergence analyses of the proposed algorithms obtained from the simulation study are also found to be in agreement with the theoretical analysis. The remarkable and interesting aspect of the proposed block-based algorithms is that their communication overheads per node and latencies are less than those of the conventional algorithms by a factor as high as the block size used in the algorithms.
Penalized linear regression for discrete ill-posed problems: A hybrid least-squares and mean-squared error approach

KAUST Repository

Suliman, Mohamed Abdalla Elhag

2016-12-19

This paper proposes a new approach to find the regularization parameter for linear least-squares discrete ill-posed problems. In the proposed approach, an artificial perturbation matrix with a bounded norm is forced into the discrete ill-posed model matrix. This perturbation is introduced to enhance the singular-value (SV) structure of the matrix and hence to provide a better solution. The proposed approach is derived to select the regularization parameter in a way that minimizes the mean-squared error (MSE) of the estimator. Numerical results demonstrate that the proposed approach outperforms a set of benchmark methods in most cases when applied to different scenarios of discrete ill-posed problems. Jointly, the proposed approach enjoys the lowest run-time and offers the highest level of robustness amongst all the tested methods.
Analytic properties of the relativistic Thomas-Fermi equation and the total energy of atomic ions

International Nuclear Information System (INIS)

March, N.H.; Senatore, G.

1985-06-01

The analytic properties of solutions of the relativistic Thomas-Fermi equation which tend to zero at infinity are first examined, the neutral atom solution being a member of this class. A new length is shown to enter the theory, proportional to the square root of the fine structure constant. This information is used to develop a perturbation expansion around the neutral atom solution, corresponding to positive atomic ions with finite but large radii. The limiting law relating ionic radius to the degree of ionization is thereby displayed in functional form, and solved explicitly to lowest order in the fine structure constant. To embrace this knowledge of heavy positive ions, as well as results from the one-electron Dirac equation, a proposal is then advanced as to the analytic form of the relativistic total energy E(Z,N) of an atomic ion with nuclear charge Ze and total number of electrons N. The fact that, for N>1, the nucleus is known only to bind Z+n electrons, where n is 1 or 2, indicates non-analyticity in the complex Z plane, represented by a circle of radius Z approx.= N. Such non-analyticity is also a property of the non-relativistic energy derived from the many-electron Schroedinger equation. The relativistic theory, however, must also embody a second type of non-analyticity associated with the known property for N=1 that the Dirac equation predicts electron-positron pair production when the electronic binding energy becomes equal to twice the electron rest mass energy. This corresponds to a second circle of non-analyticity in E(Z,N), and hence to a Taylor-Laurent expansion of this quantity in the atomic number Z. The relation of this expansion to the Layzer-Bahcall series is finally discussed. (author)
Microscopic 57 Fe electric-field-gradient and anisotropic mean-squared-displacement tensors: ferrous chloride tetrahydrate

International Nuclear Information System (INIS)

Bull, James N.; Fitchett, Christopher M.; Tennant, W. Craighead

2010-01-01

This paper reports the determination of the electric-field-gradient and mean-squared-displacement tensors in 57 Fe symmetry-related sites of 1-bar Laue class in monoclinic FeCl 2 .4H 2 O at room temperature by single-crystal Mössbauer spectroscopy. Contrary to all previous work, the mean-squared-displacement matrix (tensor), , is not constrained to be isotropic resulting in the determination of physically meaningful estimates of microscopic (local) electric-field gradient (efg) and tensors. As a consequence of anisotropy in the tensor the absorber recoilless fractions are also anisotropic. As expected of a low-symmetry site, Laue class 1-bar in this case, no two principal axes of the efg and tensors are coaxial, within the combined errors in the two. Further, no principal direction of the efg tensor seems related to bond directions in the unit cell. Within error, and in agreement with an earlier study of sodium nitroprusside, it appears that the tensor principal directions lie close to the crystallographic axes suggesting that they are determined by long wavelength (phonon) vibrations in the crystal rather than by approximate local symmetry about the 57 Fe nucleus. Concurrent with the Mössbauer measurements, we determined as part of a new X-ray structural determination, precise atomic displacement parameters (ADPs) leading to an alternative determination of the matrix (tensor). The average of the eigenvalues of the Mössbauer-determined exceeds that of the average of the X-ray-determined eigenvalues by a factor of around 2.2. Assuming isotropic absorber recoilless fractions leads to substantially the same (macroscopic) efg tensor as had been determined in earlier work. Taking 1/3 x the trace of the anisotropic absorber recoilless fractions leads to an isotropic value of 0.304 in good agreement with earlier single crystal studies where isotropy was assumed.
Hydrogen-like atom in laser field: Invariant atomic parameters in the ground state

International Nuclear Information System (INIS)

Bondarev, I.V.; Kuten, S.A.

1994-07-01

The invariant atomic parameters (dynamical vector and tensor polarizabilities) of hydrogen-like atom in the ground 1S 1/2 state are calculated analytically by means of the Laplace transform of the radial Schroedinger equation. The obtained analytical expressions have been written in the compact form as a sum of linear and squared combinations of Gauss hypergeometric functions 2 F 1 . The frequency dependence of the invariant atomic parameters is analyzed. (author). 24 refs, 1 fig
Mean-Square Convergence of Drift-Implicit One-Step Methods for Neutral Stochastic Delay Differential Equations with Jump Diffusion

Directory of Open Access Journals (Sweden)

Lin Hu

2011-01-01

Full Text Available A class of drift-implicit one-step schemes are proposed for the neutral stochastic delay differential equations (NSDDEs driven by Poisson processes. A general framework for mean-square convergence of the methods is provided. It is shown that under certain conditions global error estimates for a method can be inferred from estimates on its local error. The applicability of the mean-square convergence theory is illustrated by the stochastic θ-methods and the balanced implicit methods. It is derived from Theorem 3.1 that the order of the mean-square convergence of both of them for NSDDEs with jumps is 1/2. Numerical experiments illustrate the theoretical results. It is worth noting that the results of mean-square convergence of the stochastic θ-methods and the balanced implicit methods are also new.
Least-squares Minimization Approaches to Interpret Total Magnetic Anomalies Due to Spheres

Science.gov (United States)

Abdelrahman, E. M.; El-Araby, T. M.; Soliman, K. S.; Essa, K. S.; Abo-Ezz, E. R.

2007-05-01

We have developed three different least-squares approaches to determine successively: the depth, magnetic angle, and amplitude coefficient of a buried sphere from a total magnetic anomaly. By defining the anomaly value at the origin and the nearest zero-anomaly distance from the origin on the profile, the problem of depth determination is transformed into the problem of finding a solution of a nonlinear equation of the form f(z)=0. Knowing the depth and applying the least-squares method, the magnetic angle and amplitude coefficient are determined using two simple linear equations. In this way, the depth, magnetic angle, and amplitude coefficient are determined individually from all observed total magnetic data. The method is applied to synthetic examples with and without random errors and tested on a field example from Senegal, West Africa. In all cases, the depth solutions are in good agreement with the actual ones.
Minimum Mean-Square Error Estimation of Mel-Frequency Cepstral Features

DEFF Research Database (Denmark)

Jensen, Jesper; Tan, Zheng-Hua

2015-01-01

In this work we consider the problem of feature enhancement for noise-robust automatic speech recognition (ASR). We propose a method for minimum mean-square error (MMSE) estimation of mel-frequency cepstral features, which is based on a minimum number of well-established, theoretically consistent......-of-the-art MFCC feature enhancement algorithms within this class of algorithms, while theoretically suboptimal or based on theoretically inconsistent assumptions, perform close to optimally in the MMSE sense....
On Solution of Total Least Squares Problems with Multiple Right-hand Sides

Czech Academy of Sciences Publication Activity Database

Hnětynková, I.; Plešinger, Martin; Strakoš, Zdeněk

2008-01-01

Roč. 8, č. 1 (2008), s. 10815-10816 ISSN 1617-7061 R&D Projects: GA AV ČR IAA100300802 Institutional research plan: CEZ:AV0Z10300504 Keywords : total least squares problem * multiple right-hand sides * linear approximation problem Subject RIV: BA - General Mathematics
On the multivariate total least-squares approach to empirical coordinate transformations. Three algorithms

Science.gov (United States)

Schaffrin, Burkhard; Felus, Yaron A.

2008-06-01

The multivariate total least-squares (MTLS) approach aims at estimating a matrix of parameters, Ξ, from a linear model ( Y- E Y = ( X- E X ) · Ξ) that includes an observation matrix, Y, another observation matrix, X, and matrices of randomly distributed errors, E Y and E X . Two special cases of the MTLS approach include the standard multivariate least-squares approach where only the observation matrix, Y, is perturbed by random errors and, on the other hand, the data least-squares approach where only the coefficient matrix X is affected by random errors. In a previous contribution, the authors derived an iterative algorithm to solve the MTLS problem by using the nonlinear Euler-Lagrange conditions. In this contribution, new lemmas are developed to analyze the iterative algorithm, modify it, and compare it with a new ‘closed form’ solution that is based on the singular-value decomposition. For an application, the total least-squares approach is used to estimate the affine transformation parameters that convert cadastral data from the old to the new Israeli datum. Technical aspects of this approach, such as scaling the data and fixing the columns in the coefficient matrix are investigated. This case study illuminates the issue of “symmetry” in the treatment of two sets of coordinates for identical point fields, a topic that had already been emphasized by Teunissen (1989, Festschrift to Torben Krarup, Geodetic Institute Bull no. 58, Copenhagen, Denmark, pp 335-342). The differences between the standard least-squares and the TLS approach are analyzed in terms of the estimated variance component and a first-order approximation of the dispersion matrix of the estimated parameters.
Golden mean energy equals highest atomic electron orbital energy

Energy Technology Data Exchange (ETDEWEB)

Malinowski, Leonard J. [Interdisciplinary Research Club, P.O. Box 371, Monroeville, PA 15146 (United States)], E-mail: LJMalinowski@gmail.com

2009-12-15

The golden mean numerical value {phi} = 0.5({radical}5 - 1) has been given a physical manifestation through E infinity theory. This short paper relates the golden mean energy 0.618034 MeV to atomic electron orbitals.
Golden mean energy equals highest atomic electron orbital energy

International Nuclear Information System (INIS)

Malinowski, Leonard J.

2009-01-01

The golden mean numerical value φ = 0.5(√5 - 1) has been given a physical manifestation through E infinity theory. This short paper relates the golden mean energy 0.618034 MeV to atomic electron orbitals.
The Mean Excitation Energy of Atomic Ions

DEFF Research Database (Denmark)

Sauer, Stephan; Oddershede, Jens; Sabin, John R.

2015-01-01

A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum...
Exponential mean-square stability of two classes of theta Milstein methods for stochastic delay differential equations

Science.gov (United States)

Rouz, Omid Farkhondeh; Ahmadian, Davood; Milev, Mariyan

2017-12-01

This paper establishes exponential mean square stability of two classes of theta Milstein methods, namely split-step theta Milstein (SSTM) method and stochastic theta Milstein (STM) method, for stochastic differential delay equations (SDDEs). We consider the SDDEs problem under a coupled monotone condition on drift and diffusion coefficients, as well as a necessary linear growth condition on the last term of theta Milstein method. It is proved that the SSTM method with θ ∈ [0, ½] can recover the exponential mean square stability of the exact solution with some restrictive conditions on stepsize, but for θ ∈ (½, 1], we proved that the stability results hold for any stepsize. Then, based on the stability results of SSTM method, we examine the exponential mean square stability of the STM method and obtain the similar stability results to that of the SSTM method. In the numerical section the figures show thevalidity of our claims.

Analysis of total least squares in estimating the parameters of a mortar trajectory

Energy Technology Data Exchange (ETDEWEB)

Lau, D.L.; Ng, L.C.

1994-12-01

Least Squares (LS) is a method of curve fitting used with the assumption that error exists in the observation vector. The method of Total Least Squares (TLS) is more useful in cases where there is error in the data matrix as well as the observation vector. This paper describes work done in comparing the LS and TLS results for parameter estimation of a mortar trajectory based on a time series of angular observations. To improve the results, we investigated several derivations of the LS and TLS methods, and early findings show TLS provided slightly, 10%, improved results over the LS method.
Accurate human limb angle measurement: sensor fusion through Kalman, least mean squares and recursive least-squares adaptive filtering

Science.gov (United States)

Olivares, A.; Górriz, J. M.; Ramírez, J.; Olivares, G.

2011-02-01

Inertial sensors are widely used in human body motion monitoring systems since they permit us to determine the position of the subject's limbs. Limb angle measurement is carried out through the integration of the angular velocity measured by a rate sensor and the decomposition of the components of static gravity acceleration measured by an accelerometer. Different factors derived from the sensors' nature, such as the angle random walk and dynamic bias, lead to erroneous measurements. Dynamic bias effects can be reduced through the use of adaptive filtering based on sensor fusion concepts. Most existing published works use a Kalman filtering sensor fusion approach. Our aim is to perform a comparative study among different adaptive filters. Several least mean squares (LMS), recursive least squares (RLS) and Kalman filtering variations are tested for the purpose of finding the best method leading to a more accurate and robust limb angle measurement. A new angle wander compensation sensor fusion approach based on LMS and RLS filters has been developed.
Accurate human limb angle measurement: sensor fusion through Kalman, least mean squares and recursive least-squares adaptive filtering

International Nuclear Information System (INIS)

Olivares, A; Olivares, G; Górriz, J M; Ramírez, J

2011-01-01

Inertial sensors are widely used in human body motion monitoring systems since they permit us to determine the position of the subject's limbs. Limb angle measurement is carried out through the integration of the angular velocity measured by a rate sensor and the decomposition of the components of static gravity acceleration measured by an accelerometer. Different factors derived from the sensors' nature, such as the angle random walk and dynamic bias, lead to erroneous measurements. Dynamic bias effects can be reduced through the use of adaptive filtering based on sensor fusion concepts. Most existing published works use a Kalman filtering sensor fusion approach. Our aim is to perform a comparative study among different adaptive filters. Several least mean squares (LMS), recursive least squares (RLS) and Kalman filtering variations are tested for the purpose of finding the best method leading to a more accurate and robust limb angle measurement. A new angle wander compensation sensor fusion approach based on LMS and RLS filters has been developed
Relativistic total energy and chemical potential of heavy atoms and positive ions

International Nuclear Information System (INIS)

Hill, S.H.; Grout, P.J.; March, N.H.

1984-01-01

The relativistic Thomas-Fermi theory, with a finite nucleus, is used to study the variation of the chemical potential μ with atomic number Z and number of electrons N (N <= Z). The difference between the total energy of positive ions and that of the corresponding neutral atom has been obtained. The scaling predictions are confirmed by numerical calculations. The first principles calculation of the relativistic Thomas-Fermi total energy of neutral atoms is also studied. (author)
Analysis of S-box in Image Encryption Using Root Mean Square Error Method

Science.gov (United States)

Hussain, Iqtadar; Shah, Tariq; Gondal, Muhammad Asif; Mahmood, Hasan

2012-07-01

The use of substitution boxes (S-boxes) in encryption applications has proven to be an effective nonlinear component in creating confusion and randomness. The S-box is evolving and many variants appear in literature, which include advanced encryption standard (AES) S-box, affine power affine (APA) S-box, Skipjack S-box, Gray S-box, Lui J S-box, residue prime number S-box, Xyi S-box, and S8 S-box. These S-boxes have algebraic and statistical properties which distinguish them from each other in terms of encryption strength. In some circumstances, the parameters from algebraic and statistical analysis yield results which do not provide clear evidence in distinguishing an S-box for an application to a particular set of data. In image encryption applications, the use of S-boxes needs special care because the visual analysis and perception of a viewer can sometimes identify artifacts embedded in the image. In addition to existing algebraic and statistical analysis already used for image encryption applications, we propose an application of root mean square error technique, which further elaborates the results and enables the analyst to vividly distinguish between the performances of various S-boxes. While the use of the root mean square error analysis in statistics has proven to be effective in determining the difference in original data and the processed data, its use in image encryption has shown promising results in estimating the strength of the encryption method. In this paper, we show the application of the root mean square error analysis to S-box image encryption. The parameters from this analysis are used in determining the strength of S-boxes
A kilobyte rewritable atomic memory

Science.gov (United States)

Kalff, Floris; Rebergen, Marnix; Fahrenfort, Nora; Girovsky, Jan; Toskovic, Ranko; Lado, Jose; FernáNdez-Rossier, JoaquíN.; Otte, Sander

The ability to manipulate individual atoms by means of scanning tunneling microscopy (STM) opens op opportunities for storage of digital data on the atomic scale. Recent achievements in this direction include data storage based on bits encoded in the charge state, the magnetic state, or the local presence of single atoms or atomic assemblies. However, a key challenge at this stage is the extension of such technologies into large-scale rewritable bit arrays. We demonstrate a digital atomic-scale memory of up to 1 kilobyte (8000 bits) using an array of individual surface vacancies in a chlorine terminated Cu(100) surface. The chlorine vacancies are found to be stable at temperatures up to 77 K. The memory, crafted using scanning tunneling microscopy at low temperature, can be read and re-written automatically by means of atomic-scale markers, and offers an areal density of 502 Terabits per square inch, outperforming state-of-the-art hard disk drives by three orders of magnitude.
A generalized mean-squared displacement from inelastic fixed window scans of incoherent neutron scattering as a model-free indicator of anomalous diffusion confinement

International Nuclear Information System (INIS)

Roosen-Runge, F.; Seydel, T.

2015-01-01

Elastic fixed window scans of incoherent neutron scattering are an established and frequently employed method to study dynamical changes, usually over a broad temperature range or during a process such as a conformational change in the sample. In particular, the apparent mean-squared displacement can be extracted via a model-free analysis based on a solid physical interpretation as an effective amplitude of molecular motions. Here, we provide a new account of elastic and inelastic fixed window scans, defining a generalized mean-squared displacement for all fixed energy transfers. We show that this generalized mean-squared displacement in principle contains all information on the real mean-square displacement accessible in the instrumental time window. The derived formula provides a clear understanding of the effects of instrumental resolution on the apparent mean-squared displacement. Finally, we show that the generalized mean-square displacement can be used as a model-free indicator on confinement effects within the instrumental time window. (authors)
The role of total-reflection x-ray fluorescence in atomic spectroscopy

International Nuclear Information System (INIS)

Toelg, G.; Klockenkaemper, R.

1993-01-01

Total-reflection X-ray fluorescence (TXRF) is a universal and economic method for the simultaneous determination of elements with atomic numbers > 11 down to the lower pg-level. It is a microanalytical tool for the analysis of small sample amounts placed on flat carriers and for contaminations on flat sample surfaces. Analyses of stratified near-surface layers are made possible by varying the incident angle of the primary beam in the region of total-reflection. This non-destructive method is especially suitable for thin layers of a few nanometres, deposited on wafer material although not usable as a microprobe method with a high lateral resolution. Furthermore, depth profiles of biological samples can be recorded by means of microtome sectioning of only a few micrometres, as, for example in the gradient analysis of human organs. In addition to micro- and surface-layer analysis, TXRF is effectively applied to element trace analysis. Homogeneous solutions, for example aqueous solutions, high-purity acids or body fluids, are pipetted onto carriers and, after evaporation, the dry residues are analyzed directly down to the pg/ml region. Particularly advantageous is the absence of matrix effects, so that an easy calibration can be carried out by adding a single internal standard element. A digestion or separation step preceding the actual determination becomes necessary if a more complex matrix is to be analysed or especially low detection limits have to be reached. A critical evaluation of the recent developments in atomic spectroscopy places TXRF in a leading position. Its outstanding features compete with those of e.g. electrothermal atomic absorption spectrometry (ETAAS), microwave induced plasma optical emission spectroscopy (MIP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) in the field of micro- and trace analysis and with Rutherford backscattering (RBS) and secondary ion mass spectrometry (SIMS) in the surface-layer analysis. (author)
Optical pattern recognition architecture implementing the mean-square error correlation algorithm

Science.gov (United States)

Molley, Perry A.

1991-01-01

An optical architecture implementing the mean-square error correlation algorithm, MSE=.SIGMA.[I-R].sup.2 for discriminating the presence of a reference image R in an input image scene I by computing the mean-square-error between a time-varying reference image signal s.sub.1 (t) and a time-varying input image signal s.sub.2 (t) includes a laser diode light source which is temporally modulated by a double-sideband suppressed-carrier source modulation signal I.sub.1 (t) having the form I.sub.1 (t)=A.sub.1 [1+.sqroot.2m.sub.1 s.sub.1 (t)cos (2.pi.f.sub.o t)] and the modulated light output from the laser diode source is diffracted by an acousto-optic deflector. The resultant intensity of the +1 diffracted order from the acousto-optic device is given by: I.sub.2 (t)=A.sub.2 [+2m.sub.2.sup.2 s.sub.2.sup.2 (t)-2.sqroot.2m.sub.2 (t) cos (2.pi.f.sub.o t] The time integration of the two signals I.sub.1 (t) and I.sub.2 (t) on the CCD deflector plane produces the result R(.tau.) of the mean-square error having the form: R(.tau.)=A.sub.1 A.sub.2 {[T]+[2m.sub.2.sup.2.multidot..intg.s.sub.2.sup.2 (t-.tau.)dt]-[2m.sub.1 m.sub.2 cos (2.tau.f.sub.o .tau.).multidot..intg.s.sub.1 (t)s.sub.2 (t-.tau.)dt]} where: s.sub.1 (t) is the signal input to the diode modulation source: s.sub.2 (t) is the signal input to the AOD modulation source; A.sub.1 is the light intensity; A.sub.2 is the diffraction efficiency; m.sub.1 and m.sub.2 are constants that determine the signal-to-bias ratio; f.sub.o is the frequency offset between the oscillator at f.sub.c and the modulation at f.sub.c +f.sub.o ; and a.sub.o and a.sub.1 are constant chosen to bias the diode source and the acousto-optic deflector into their respective linear operating regions so that the diode source exhibits a linear intensity characteristic and the AOD exhibits a linear amplitude characteristic.
Two Enhancements of the Logarithmic Least-Squares Method for Analyzing Subjective Comparisons

Science.gov (United States)

1989-03-25

error term. 1 For this model, the total sum of squares ( SSTO ), defined as n 2 SSTO = E (yi y) i=1 can be partitioned into error and regression sums...of the regression line around the mean value. Mathematically, for the model given by equation A.4, SSTO = SSE + SSR (A.6) A-4 where SSTO is the total...sum of squares (i.e., the variance of the yi’s), SSE is error sum of squares, and SSR is the regression sum of squares. SSTO , SSE, and SSR are given
Universal dependence of the total number albedo of photons on the mean number of photon scatterings

Directory of Open Access Journals (Sweden)

Ljubenov Vladan L.

2011-01-01

Full Text Available This paper presents the results of research on photon reflection from plane targets based on Monte Carlo simulations performed by the MCNP code. Five materials (water, concrete, aluminum, iron, and copper are examined in the area of initial photon energies of up to 200 keV. The values of the total number albedo for photons dependent on the initial photon energy or the mean number of photon scatterings are calculated and graphically presented. We have shown that the values of the total number albedo for different target materials, expressed as a function of the mean number of photon scatterings, are in good agreement with each other and can be approximated by simple, universal analytic functions obtained by the least squares method. The accuracy of these analytic appoximations is confirmed by their comparison with the results of PENELOPE and FOTELP Monte Carlo codes.
Low-energy-spread ion bunches from a trapped atomic gas

NARCIS (Netherlands)

Reijnders, M.P.; Kruisbergen, van P.A.; Taban, G.; Geer, van der S.B.; Mutsaers, P.H.A.; Vredenbregt, E.J.D.; Luiten, O.J.

2009-01-01

We present time-of-flight measurements of the longitudinal energy spread of pulsed ultracold ion beams, produced by near-threshold ionization of rubidium atoms captured in a magneto-optical atom trap. Well-defined pulsed beams have been produced with energies of only 1 eV and a root-mean-square
Intensification of oily waste waters purification by means of liquid atomization

Science.gov (United States)

Eskin, A. A.; Tkach, N. S.; Kim, M. I.; Zakharov, G. A.

2017-10-01

In this research, a possibility of using liquid atomization for improving the efficiency of purification of wastewater by different methods has been studied. By the introduced method and an experimental setup for wastewater purification, saturation rate increases with its purification by means of dissolved air flotation. Liquid atomization under excess pressure allows to gain a large interfacial area between the saturated liquid and air, which may increase the rate of purified liquid saturation almost twice, compared to the existing methods of saturation. Current disadvantages of liquid atomization used for intensification of wastewater purification include high energy cost and secondary emulsion of polluting agents. It is also known that by means of liquid atomization a process of ozonizing can be intensified. Large contact surface between the purified liquid and ozone-air mixture increases the oxidizing efficiency, which allows to diminish ozone discharge. Liquid atomization may be used for purification of wastewaters by ultraviolet radiation. Small drops of liquid will be proportionally treated by ultraviolet, which makes it possible to do purification even of turbid wastewaters. High-speed liquid motion will prevent the pollution of quartz tubes of ultraviolet lamps.
Studies on low energy ion-atom collisions by means of electron-spectroscopy

International Nuclear Information System (INIS)

Hirosi Suzuki

1991-01-01

The typical results of studies on autoionization processes produced by low energy ion-atom collisions are given by means of the ejected electron spectroscopy, which have been performed by Atomic Physics Group of Sophia University
Square through tube

International Nuclear Information System (INIS)

Akita, Junji; Honma, Toei.

1975-01-01

Object: To provide a square through tube involving thermal movement in pipelines such as water supply pump driving turbine exhaust pipe (square-shaped), which is wide in freedom with respect to shape and dimension thereof for efficient installation at site. Structure: In a through tube to be airtightly retained for purpose of decontamination in an atomic power plant, comprising a seal rubber plate, a band and a bolt and a nut for securing said plate, the seal rubber plate being worked into the desired shape so that it may be placed in intimate contact with the concrete floor surface by utilization of elasticity of rubber, thereby providing airtightness at a corner portion of the square tube. (Kamimura, M.)
On the mean squared error of the ridge estimator of the covariance and precision matrix

NARCIS (Netherlands)

van Wieringen, Wessel N.

2017-01-01

For a suitably chosen ridge penalty parameter, the ridge regression estimator uniformly dominates the maximum likelihood regression estimator in terms of the mean squared error. Analogous results for the ridge maximum likelihood estimators of covariance and precision matrix are presented.
Atomic resonances above the total ionization energy

International Nuclear Information System (INIS)

Doolen, G.

1975-01-01

A rigorous result obtained using the theory associated with dilatation analytic potentials is that by performing a complex coordinate rotation, r/subj/ → r/subj/e/subi//sup theta/, on a Hamiltonian whose potential involves only pairwise Coulombic interactions, one can show that when theta = π/2, no complex eigenvalues (resonances) appear whose energies have a real part greater than the total ionization energy of the atomic system. This appears to conflict with experimental results of Walton, Peart, and Dolder, who find resonance behavior above the total ionization energy of the H -- system and also the theoretical stabilization results of Taylor and Thomas for the same system. A possible resolution of this apparent conflict is discussed and a calculation to check its validity is proposed
Local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys investigated by EXAFS method

International Nuclear Information System (INIS)

Antonowicz, J.; Pietnoczka, A.; Zalewski, W.; Bacewicz, R.; Stoica, M.; Georgarakis, K.; Yavari, A.R.

2011-01-01

Research highlights: → Coordination number, interatomic distances and mean square atomic displacement in Zr-Cu and Zr-Cu-Al glasses. → Icosahedral symmetry in local atomic structure. → Deviation from random mixing behavior resulting from Al addition. - Abstract: We report on extended X-ray absorption fine structure (EXAFS) study of rapidly quenched Zr-Cu and Zr-Cu-Al glassy alloys. The local atomic order around Zr and Cu atoms was investigated. From the EXAFS data fitting the values of coordination number, interatomic distances and mean square atomic displacement were obtained for wide range of compositions. It was found that icosahedral symmetry rather than that of corresponding crystalline analogs dominates in the local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys. Judging from bonding preferences we conclude that addition of Al as an alloying element results in considerable deviation from random mixing behavior observed in binary Zr-Cu alloys.
Use of total cross sections for obtaining the anisotropic interaction potential in atom--diatom system

International Nuclear Information System (INIS)

Eccles, J.; Secrest, D.

1977-01-01

A study is made of the ''conservation of the total cross section'' and the ''equivalence of the total cross section'' rules for scattering from H 2 . It is shown that these rules are a better approximation than the random phase approximation would indicate. Cross section formulas are given for scattering atoms from m/sub j/ state selected molecules and it is shown that total cross sections for state selected molecules depend on the anisotropic part of the interaction potential, while the spin-averaged total cross section often depends only on the spherically symmetric part of the interaction potential. The total spin-averaged cross section is thus independent of the initial rotation state of the molecule and depends only on the relative collision energy. It is further demonstrated that isotopic substitution, which shifts the center of mass changing the symmetric part of the interaction potential, has too small an effect on the total cross section to be useful as a means of determining the anisotropy of the potential
On the mean square displacements (MSD) of Hg and Te in HgTe

International Nuclear Information System (INIS)

Madhavan, Y.; Ramachandran, K.

1989-01-01

The mean square displacements (MSD) of Hg and Te in the perfect system of HgTe are worked out in the modified rigid ion model of Plumelle and Vandevyver. Also the MSD of Hg and Te neighbours around anion and cation vacancies in HgTe are worked out giving an active role for the vacancy following the theory of Maradudin et al. The results are compared with experimental values. (author)

Goldberger-treiman relation and nucleon's mean square radius of strong interaction in the Skyrme model

International Nuclear Information System (INIS)

Li Bingan

1988-01-01

In this letter it is shown that even in m π ≠ 0 case the Goldberger-Treiman relation is still hold in the Skyrme model. The mean square radius of strong interaction of nucleon 2 > s 1/2 is computed in the Skyrme model
Fluorescent atom coincidence spectroscopy of extremely neutron-deficient barium isotopes

International Nuclear Information System (INIS)

Wells, S.A.; Evans, D.E.; Griffith, J.A.R.; Eastham, D.A.; Groves, J.; Smith, J.R.H.; Tolfree, D.W.L.; Warner, D.D.; Billowes, J.; Grant, I.S.; Walker, P.M.

1988-01-01

Fluorescent atom coincidence spectroscopy (FACS) has been used to measure the nuclear mean square radii and moments of the extremely neutron-deficient isotopes 120-124 Ba. At N=65 an abrupt change in nuclear mean square charge radii is observed which can be understood in terms of the occupation of the spin-orbit partner g 7/2 5/2[413] neutron and g 9/2 9/2[404] proton orbitals and the consequent enhancement of the n-p interaction. (orig.)
Prediction of toxicity of nitrobenzenes using ab initio and least squares support vector machines

International Nuclear Information System (INIS)

Niazi, Ali; Jameh-Bozorghi, Saeed; Nori-Shargh, Davood

2008-01-01

A quantitative structure-property relationship (QSPR) study is suggested for the prediction of toxicity (IGC 50 ) of nitrobenzenes. Ab initio theory was used to calculate some quantum chemical descriptors including electrostatic potentials and local charges at each atom, HOMO and LUMO energies, etc. Modeling of the IGC 50 of nitrobenzenes as a function of molecular structures was established by means of the least squares support vector machines (LS-SVM). This model was applied for the prediction of the toxicity (IGC 50 ) of nitrobenzenes, which were not in the modeling procedure. The resulted model showed high prediction ability with root mean square error of prediction of 0.0049 for LS-SVM. Results have shown that the introduction of LS-SVM for quantum chemical descriptors drastically enhances the ability of prediction in QSAR studies superior to multiple linear regression and partial least squares
Ordinary least square regression, orthogonal regression, geometric mean regression and their applications in aerosol science

International Nuclear Information System (INIS)

Leng Ling; Zhang Tianyi; Kleinman, Lawrence; Zhu Wei

2007-01-01

Regression analysis, especially the ordinary least squares method which assumes that errors are confined to the dependent variable, has seen a fair share of its applications in aerosol science. The ordinary least squares approach, however, could be problematic due to the fact that atmospheric data often does not lend itself to calling one variable independent and the other dependent. Errors often exist for both measurements. In this work, we examine two regression approaches available to accommodate this situation. They are orthogonal regression and geometric mean regression. Comparisons are made theoretically as well as numerically through an aerosol study examining whether the ratio of organic aerosol to CO would change with age
Evaluation of surface roughness of orthodontic wires by means of atomic force microscopy.

Science.gov (United States)

D'Antò, Vincenzo; Rongo, Roberto; Ametrano, Gianluca; Spagnuolo, Gianrico; Manzo, Paolo; Martina, Roberto; Paduano, Sergio; Valletta, Rosa

2012-09-01

To compare the surface roughness of different orthodontic archwires. Four nickel-titanium wires (Sentalloy(®), Sentalloy(®) High Aesthetic, Titanium Memory ThermaTi Lite(®), and Titanium Memory Esthetic(®)), three β-titanium wires (TMA(®), Colored TMA(®), and Beta Titanium(®)), and one stainless-steel wire (Stainless Steel(®)) were considered for this study. Three samples for each wire were analyzed by atomic force microscopy (AFM). Three-dimensional images were processed using Gwiddion software, and the roughness average (Ra), the root mean square (Rms), and the maximum height (Mh) values of the scanned surface profile were recorded. Statistical analysis was performed by one-way analysis of variance (ANOVA) followed by Tukey's post hoc test (P Sentalloy High Aesthetic was the roughest (Ra = 133.5 ± 10.8; Rms = 165.8 ± 9.8; Mh = 949.6 ± 192.1) of the archwires. The surface quality of the wires investigated differed significantly. Ion implantation effectively reduced the roughness of TMA. Moreover, Teflon(®)-coated Titanium Memory Esthetic was less rough than was ion-implanted Sentalloy High Aesthetic.
Device to investigate samples by means of flameless atomic absorption measurement

International Nuclear Information System (INIS)

Sperling, K.R.

1977-01-01

An improvement on a device to investigate samples by means of flameless atomic absorption measurement is suggested in which one aims to produce a most complete possible atomic clond from the sample to be investigated within the sample space defined by the beam bundle, through which the measuring beam bundle is passed. According to the invention, the tubular sample space should be closed by an optically penetrable window on one side. (RW) [de
Mean-squared displacements for normal and anomalous diffusion of grains

International Nuclear Information System (INIS)

Trigger, S A; Heijst, G J F van; Schram, P P J M

2005-01-01

The problem of normal and anomalous space difiusion is formulated on the basis of the integral equations with various type of the probability transition functions for difiusion (PTD functions). For the cases of stationary and time-independent PTD functions the method of fractional differentiation is avoided to construct the correct probability distributions for arbitrary distances, what is important for applications to different stochastic problems. A new general integral equation for the particle distribution, which contains the time-dependent PTD function with one or, for more complicated physical situations, with two times, is formulated and discussed. On this basis fractional differentiation in time is also avoided and a wide class of time dependent PTD functions can be investigated. Calculations of the mean-squared displacements for the various cases are performed on the basis of formulated approach. The particular problems for the PTD functions, dependable from one and for two times, are solved
On mean square displacement behaviors of anomalous diffusions with variable and random orders

International Nuclear Information System (INIS)

Sun Hongguang; Chen Wen; Sheng Hu; Chen Yangquan

2010-01-01

Mean square displacement (MSD) is used to characterize anomalous diffusion. Recently, models of anomalous diffusion with variable-order and random-order were proposed, but no MSD analysis has been given so far. The purpose of this Letter is to offer a concise derivation of MSD functions for the variable-order model and the random-order model. Numerical results are presented to illustrate the analytical results. In addition, we show how to establish a variable-random-order model for a given MSD function which has clear application potentials.
The total Hartree-Fock energy-eigenvalue sum relationship in atoms

International Nuclear Information System (INIS)

Sen, K.D.

1979-01-01

Using the well known relationships for the isoelectronic changes in the total Hartree-Fock energy, nucleus-electron attraction energy and electron-electron repulsion energy in atoms a simple polynomial expansion in Z is obtained for the sum of the eigenvalues which can be used to calculate the total Hartree-Fock energy. Numerical results are presented for 2-10 electron series to show that the present relationship is a better approximation than the other available energy-eigenvalue relationships. (author)
Classical calculation of the total ionization energy of helium-like atoms

International Nuclear Information System (INIS)

Karastoyanov, A.

1990-01-01

Quantum mechanics rejects the classical modelling of microworld. One of the reasons is that the Bohr's rules can not be applied for many-electron atoms and molecules. But the many-body problem in classical mechanics has no analytical solution even for 3 particles. Numerical solutions should be used. The quantum Bohr's rule expressing the moment of momentum conservation for two particles is invalid in more complicated cases. Yet Bohr reached some success for helium-like atoms. The Bohr's formula concerning helim-like atoms is deduced again in this paper and its practical reliability is analyzed with contemporary data. The binding energy of the system is obtained in the simple form E=(Z-1/4) 2 α 2 mc 2 , where Z is the atomic number, α - the fine structure constant, M - the electron mass and c - the light speed in vacuum. The calculated values are compared with experimental data on the total ionization energy of the helium-like atoms from 2 He 4 to 29 Cu 64 . The error decreases quickly with the increasing of atomic mass, reaching zero for Cu. This indicated that the main source of error is the nucleus motion. The role of other possible causes is analyzed and proves negligible. (author). 1 tab, 4 refs
Study of microwave instabilities by means of a square-well potential

International Nuclear Information System (INIS)

Kim, K.J.

1979-01-01

Microwave instabilities are analyzed in a simple model, in which the usual synchrotron oscillation of a particle is replaced by particle motion in a square-well potential. In the usual synchrotron oscillation, a particle moves along an elliptic trajectory. The most natural coordinates for such a motion are the action and the angle variables. On the other hand, the distribution of the particles along the ring is most conveniently described by azimuthal variables. The difficulty disappears if the synchrotron motion is approximated by the motion in a square-well potential. The square-well potential may seem extremely unphysical. However, it should be remarked that the form of the potential with addition of a Landau cavity looks more or less like a square-well. At any rate, the main motivation of introducing the square-well here is to simplify the mathematics of and thereby gain some insight into microwave instabilities. The model is exactly soluble. The results are in general agreement with the conclusions obtained from qualitative arguments based on coasting beam theory. However, some of the detailed features of the solution, for example the behavior of ω 2 as a function of impedance, are surprising
Atomic spectroscopy study of nuclear properties of francium and cesium isotopes

International Nuclear Information System (INIS)

Coc, A.

1986-04-01

This work is based on the study of cesium ( 118,146 Cs) and francium ( 207-213 Fr, 220-228 Fr) isotopes by hyperfine atomic spectroscopy and on the interpretation of these results from the nuclear physics point of view. The measured nuclear quantities are: the spin, the magnetic moment, the electric quadrupole moment and the mean square charge radius. The experimental method which is based on hyperfine optical pumping with a tunable laser, followed by magnetic analysis of the atoms is described in the first part. Results related to atomic physics are also presented. In the second part, these data are interpreted in the framework of nuclear models. The deformation of light cesium isomers are compared to values obtained from a theoretical self-consistent calculation. Heavy francium isotopes are situated in an area where the existence of static octupole deformations have been predicted. The odd-even staggering measured on the mean square radius is abnormal in this region. However, on the basis of experimental data, no definitive conclusion can be drawn regarding the nature of these deformations. (author)
On the normalization of total wave function of the system of an atom and a colliding electron

International Nuclear Information System (INIS)

Nashlenas, Eh.P.; Trinkunas, G.P.

1976-01-01

The scattering of an electron by an atom is considered which causes an excitation of fine structure levels. For this purpose the wave function of a system consisting of an atom and an uncoupled electron is constructed. Boundary conditions formulated in the form of an asymptotic expression are taken into account for such a function by means of scattering amplitudes. To determine scattering amplitudes it is suggested to make use of the condition of wave function normalization into the Dirac delta function. After certain mathematical transformations the unknown relations between the scattering amplitudes are obtained. The special cases of the relations obtained are discussed. When quantum numbers of the wave functions coincide, the resulting relations express the equality of fluxes of converging and diverging waves for a certain value of the total angular momentum. In the limiting case when there are no electrons in an atom (it corresponds to elastic scattering of an electron on a potential) the relations obtained express the unitarity conditions of the scattering matrix
The tilt-dependent potential of mean force of a pair of DNA oligomers from all-atom molecular dynamics simulations

International Nuclear Information System (INIS)

Cortini, Ruggero; Cheng, Xiaolin

2017-01-01

Electrostatic interactions between DNA molecules have been extensively studied experimentally and theoretically, but several aspects (e.g. its role in determining the pitch of the cholesteric DNA phase) still remain unclear. Here, we performed large-scale all-atom molecular dynamics simulations in explicit water and 150 mM sodium chloride, to reconstruct the potential of mean force (PMF) of two DNA oligomers 24 base pairs long as a function of their interaxial angle and intermolecular distance. We find that the potential of mean force is dominated by total DNA charge, and not by the helical geometry of its charged groups. The theory of homogeneously charged cylinders fits well all our simulation data, and the fit yields the optimal value of the total compensated charge on DNA to ≈65% of its total fixed charge (arising from the phosphorous atoms), close to the value expected from Manning's theory of ion condensation. The PMF calculated from our simulations does not show a significant dependence on the handedness of the angle between the two DNA molecules, or its size is on the order of 1k B T. Thermal noise for molecules of the studied length seems to mask the effect of detailed helical charge patterns of DNA. The fact that in monovalent salt the effective interaction between two DNA molecules is independent on the handedness of the tilt may suggest that alternative mechanisms are required to understand the cholesteric phase of DNA.
Ultracold Atoms in a Square Lattice with Spin-Orbit Coupling: Charge Order, Superfluidity, and Topological Signatures

Science.gov (United States)

Rosenberg, Peter; Shi, Hao; Zhang, Shiwei

2017-12-01

We present an ab initio, numerically exact study of attractive fermions in square lattices with Rashba spin-orbit coupling. The ground state of this system is a supersolid, with coexisting charge and superfluid order. The superfluid is composed of both singlet and triplet pairs induced by spin-orbit coupling. We perform large-scale calculations using the auxiliary-field quantum Monte Carlo method to provide the first full, quantitative description of the charge, spin, and pairing properties of the system. In addition to characterizing the exotic physics, our results will serve as essential high-accuracy benchmarks for the intense theoretical and especially experimental efforts in ultracold atoms to realize and understand an expanding variety of quantum Hall and topological superconductor systems.
An algorithm for total variation regularized photoacoustic imaging

DEFF Research Database (Denmark)

Dong, Yiqiu; Görner, Torsten; Kunis, Stefan

2014-01-01

Recovery of image data from photoacoustic measurements asks for the inversion of the spherical mean value operator. In contrast to direct inversion methods for specific geometries, we consider a semismooth Newton scheme to solve a total variation regularized least squares problem. During the iter......Recovery of image data from photoacoustic measurements asks for the inversion of the spherical mean value operator. In contrast to direct inversion methods for specific geometries, we consider a semismooth Newton scheme to solve a total variation regularized least squares problem. During...... the iteration, each matrix vector multiplication is realized in an efficient way using a recently proposed spectral discretization of the spherical mean value operator. All theoretical results are illustrated by numerical experiments....
Resolution Effects on the Mean Square Displacement as Obtained by the Self-Distribution-Function Procedure

International Nuclear Information System (INIS)

Benedetto, A; Magazù, S; Migliardo, F; Mondelli, C; Gonzalez, M A

2012-01-01

In the present contribution, a procedure for molecular motion characterization based on the evaluation of the Mean Square Displacement (MSD), through the Self-Distribution Function (SDF), is presented. It is shown how MSD, which represents an important observable for the characterization of dynamical properties, can be decomposed into different partial contributions associated to system dynamical processes within a specific spatial scale. It is also shown how the SDF procedure allows us to evaluate both total MSD and partial MSDs through total and partial SDFs. As a result, total MSD is the weighed sum of partial MSDs in which the weights are obtained by the fitting procedure of measured Elastic Incoherent Neutron Scattering (EINS) intensity. We apply SDF procedure to data collected,by IN13, IN10 and IN4 spectrometers (Institute Laue Langevin), on aqueous mixtures of two homologous disaccharides (sucrose and trehalose) and on dry and hydrated (H 2 O and D 2 O) lysozyme with and without disaccharides. It emerges that the hydrogen bond imposed network of the water-trehalose mixture appears to be stronger with respect to that of the water-sucrose mixture. This result can justify the higher bioprotectant effectiveness of trehalose. Furthermore, it emerges that partial MSDs of sucrose and trehalose are equivalent in the low Q domain (0÷1.7) Å −1 whereas they are different in the high Q domain (1.7÷4) Å −1 . This suggests that the higher structure sensitivity of sucrose should be related to the small spatial observation windows. Moreover, the role of the instrumental resolution in EINS is considered. The nature of the dynamical transition is highlighted and it is shown that it occurs when the system relaxation time becomes shorter than the instrumental energy time. Finally, the bioprotectants effect on protein dynamics and the amplitude of vibrations in lysozyme are presented.
Superresolution Interferometric Imaging with Sparse Modeling Using Total Squared Variation: Application to Imaging the Black Hole Shadow

Science.gov (United States)

Kuramochi, Kazuki; Akiyama, Kazunori; Ikeda, Shiro; Tazaki, Fumie; Fish, Vincent L.; Pu, Hung-Yi; Asada, Keiichi; Honma, Mareki

2018-05-01

We propose a new imaging technique for interferometry using sparse modeling, utilizing two regularization terms: the ℓ 1-norm and a new function named total squared variation (TSV) of the brightness distribution. First, we demonstrate that our technique may achieve a superresolution of ∼30% compared with the traditional CLEAN beam size using synthetic observations of two point sources. Second, we present simulated observations of three physically motivated static models of Sgr A* with the Event Horizon Telescope (EHT) to show the performance of proposed techniques in greater detail. Remarkably, in both the image and gradient domains, the optimal beam size minimizing root-mean-squared errors is ≲10% of the traditional CLEAN beam size for ℓ 1+TSV regularization, and non-convolved reconstructed images have smaller errors than beam-convolved reconstructed images. This indicates that TSV is well matched to the expected physical properties of the astronomical images and the traditional post-processing technique of Gaussian convolution in interferometric imaging may not be required. We also propose a feature-extraction method to detect circular features from the image of a black hole shadow and use it to evaluate the performance of the image reconstruction. With this method and reconstructed images, the EHT can constrain the radius of the black hole shadow with an accuracy of ∼10%–20% in present simulations for Sgr A*, suggesting that the EHT would be able to provide useful independent measurements of the mass of the supermassive black holes in Sgr A* and also another primary target, M87.
Wigner functions for nonclassical states of a collection of two-level atoms

Science.gov (United States)

Agarwal, G. S.; Dowling, Jonathan P.; Schleich, Wolfgang P.

1993-01-01

The general theory of atomic angular momentum states is used to derive the Wigner distribution function for atomic angular momentum number states, coherent states, and squeezed states. These Wigner functions W(theta,phi) are represented as a pseudo-probability distribution in spherical coordinates theta and phi on the surface of a sphere of radius the square root of j(j +1) where j is the total angular momentum.
Comparison Study of Airway Reactivity Outcomes due to a Pharmacologic Challenge Test: Impulse Oscillometry versus Least Mean Squared Analysis Techniques

Directory of Open Access Journals (Sweden)

Elena Rodriguez

2013-01-01

Full Text Available The technique of measuring transpulmonary pressure and respiratory airflow with manometry and pneumotachography using the least mean squared analysis (LMS has been used broadly in both preclinical and clinical settings for the evaluation of neonatal respiratory function during tidal volume breathing for lung tissue and airway frictional mechanical properties measurements. Whereas the technique of measuring respiratory function using the impulse oscillation technique (IOS involves the assessment of the relationship between pressure and flow using an impulse signal with a range of frequencies, requires less cooperation and provides more information on total respiratory system resistance (chest wall, lung tissue, and airways. The present study represents a preclinical animal study to determine whether these respiratory function techniques (LMS and IOS are comparable in detecting changes in respiratory resistance derived from a direct pharmacological challenge.

A New Hybrid Approach for Wind Speed Prediction Using Fast Block Least Mean Square Algorithm and Artificial Neural Network

Directory of Open Access Journals (Sweden)

Ummuhan Basaran Filik

2016-01-01

Full Text Available A new hybrid wind speed prediction approach, which uses fast block least mean square (FBLMS algorithm and artificial neural network (ANN method, is proposed. FBLMS is an adaptive algorithm which has reduced complexity with a very fast convergence rate. A hybrid approach is proposed which uses two powerful methods: FBLMS and ANN method. In order to show the efficiency and accuracy of the proposed approach, seven-year real hourly collected wind speed data sets belonging to Turkish State Meteorological Service of Bozcaada and Eskisehir regions are used. Two different ANN structures are used to compare with this approach. The first six-year data is handled as a train set; the remaining one-year hourly data is handled as test data. Mean absolute error (MAE and root mean square error (RMSE are used for performance evaluations. It is shown for various cases that the performance of the new hybrid approach gives better results than the different conventional ANN structure.
A randomised, controlled trial of circumpatellar electrocautery in total knee replacement without patellar resurfacing: a concise follow-up at a mean of 3.7 years.

Science.gov (United States)

van Jonbergen, H P W; Scholtes, V A B; Poolman, R W

2014-04-01

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years' follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years' follow-up.
Procedure for 40K isotope separation from beam of potassium atoms using optical orientation of atoms and radio-frequency excitation of target isotope

International Nuclear Information System (INIS)

Nikitin, A.I.; Velichko, A.M.; Vnukov, A.V.; Mal'tsev, K.K.; Nabiev, Sh.Sh.

1999-01-01

The procedure for potassium isotope separation, which is liable to reduce of the prise of the product as compared with the up-to-date prise of the 40 K isotope obtained by means of electromagnetic procedure for isotope separation, is proposed. The scheme assumes the increasing flow of the wanted isotope at the sacrifice of the increasing intensity of atomic beam and the increase of the selectivity of need isotope atoms at the sacrifice of the the reduction in the square of collector profile. The objective is achieved that provide of polarized state of the potassium atoms is produced by optic orientation with circular-polarized light [ru
Partial and total electronic stopping cross sections of atoms and solids for protons

International Nuclear Information System (INIS)

Kaneko, Toshiaki.

1990-12-01

Based on a wave packet theory (Phys. Rev. A40, 2188(1989); Phys. Stat. Sol. (B)156,49(1989)), partial and total electronic cross sections of target elements in atomic and solid phases with atomic number Z ranging from 2 (He) to 92 (U) are tabulated shell by shell for protons with velocity v from 0.2V 0 to 2OV 0 (V 0 =2.18 x 10 8 cm/s). (author)
Comparative studies of method for determining total mercury in fish. Dithizone and flameless atomic absorption spectrophotometry techniques

International Nuclear Information System (INIS)

Protasowicki, M.; Ociepa, A.; Chodyniecki, A.

1977-01-01

Two methods for determining total mercury in fish were compared: the dithizone and flameless atomic absorption spectrophotometry techniques. The studies involved determination of recovery when 1μg of mercury as solutions of HgCl 2 or CH 3 HgC were added to each sample of herring flesh. Mean recoveries in the dithizone method were found to be 91.4+-7.47% and 90.25+-4.73% for the two solutions respectively, while the recoveries obtained with the flameless atomic absorption spectrophotometry were 95.00+-9.13% and 98.70+-7.14%, respectively. Both techniques were used to determine the mercury content in the same herring flesh sample. The first technique showed the content of 0.050+-0.018μg Hg g -1 while the result obtained with the other one was 0.062+-0.013μg Hg g -1 . The statistical treatment of the results obtained showed no difference between the two techniques, the significance level being α=0.05. Therefore, the results obtained with the dithizone method are comparable with those obtained with the flameless atomic absorption spectrophotometry for mercury contents of the magnitude order of 0.050 ug.g -1 . (author)
Atomic mirrors for a Λ-type three-level atom

International Nuclear Information System (INIS)

Felemban, Nuha; Aldossary, Omar M; Lembessis, Vassilis E

2014-01-01

We propose atom mirror schemes for a three-level atom of Λ-type interacting with two evanescent fields, which are generated as a result of the total internal reflection of two coherent Gaussian laser beams at the interface of a dielectric prism with vacuum. The forces acting on the atom are derived by means of optical Bloch equations, based on the atomic density matrix elements. The theory is illustrated by setting up the equations of motion for 23 Na atom. Two types of excited schemes are examined, namely the cases in which the evanescent fields have polarization types of σ + −σ − and σ + −π. The equations are solved numerically and we get results for atomic trajectories for different parameters. The performance of the mirror for the two types of polarization schemes is quantified and discussed. The possibility of reflecting atoms at pre-determined directions is also discussed. (paper)
Antena Cerdas untuk Mitigasi Interferensi dengan Algoritma Least Mean Square

Directory of Open Access Journals (Sweden)

Rahmad Hidayat

2017-06-01

Full Text Available Antena cerdas pada dasarnya merupakan susunan antena dengan kemampuan pemrosesan sinyal untuk mengirim/menerima informasi secara adaptif. Kemampuan ini harus terus didalami untuk dicarikan algoritma adaptif terbaik bagi kemampuan beamforming yang diinginkan. Tulisan ini bertujuan untuk memberikan kajian dan analisis pengaruh algoritma Least Mean Square (LMS pada pengaturan nulling beam pola radiasi susunan antena cerdas dalam perannya terhadap mitigasi interferensi. Simulasi kinerja beamformer untuk sebanyak 250 iterasi dilakukan dengan tool Matlab pada kanal AWGN (Additional White Noise Gaussian dan parameter simulasi diubah untuk membandingkan dua buah harga step size m pada algoritma LMS untuk beberapa jumlah elemen antena. Pengaruh nilai step size m, terlihat pada jumlah iterasi yang dilangsungkan sebelum error noise minimum diperoleh, dimana dengan naiknya nilai step size ini maka semakin mengurangi jumlah iterasi, rata-rata menjadi 60. Dari pola respon amplitudo setelah proses beamforming , posisi sinyal utama (0 dB tepat di sudut 30° dan dihasilkan 15 posisi nulling untuk 16 elemen antena. Sumber interferensi dihilangkan / ditutup dengan menempatkan ’nulls’ dalam arah sumber interferensi tersebut di posisi 60° dan -40° dengan masing-masing level diperoleh berkisar sebesar -115 dB
The justification for the use of table of equivalent squares with respect to reference depth total scatter factor, and phantom scatter factor, for cobalt-60 teletherapy

International Nuclear Information System (INIS)

Afari, F.

2011-01-01

The use of equivalent squares is of great value and importance when determining output and depth dose data for rectangular fields. The variation with field shape of collimator scatter factors (S c ), phantom scatter factors (S c,p ) were studied using measurements on GWGP 80 cobalt - 60 teletherapy machine at the National Centre of Radiotherapy and Nuclear Medicine in the Korle-Bu Teaching Hospital. Measurements of the collimator scatter factors (S c ), phantom scatter factors (S p ) and total scatter factors (S c, p) were made at the depth of 5 cm, 10 cm, 15 cm and 20 cm in full scatter water phantom for square field side and rectangular fields of varying dimensions. The measurements were done using the source - axis distance (Sad) technique. The values of total scatter factor (S c,p ), phantom scatter factor and collimator scatter factor (S c ) obtained were used to estimate equivalent squares for the rectangular fields at the various depths. The equivalent squares were computed using the method of interpolation which is based on the scatter analysis of these scatter factors and these estimated equivalent squares were then compared with equivalent squares were then compared with equivalent square fields from BJR (supplement 21) tables of equivalent squares. The research revealed that there were average deviation of 1.5% for smaller rectangular field sizes and 8.8% for elongated rectangular field sizes between the estimated square field sizes and the equivalent square field from BJR (supplement 21) Table of equivalent square fields. The 8.8% for the elongated rectangular fields is not accepted, though such fields are rarely used in our Hospitals. It was found that the values of the equivalent square at the various depth were very consistent and do not vary with reference depth. These findings confirm that the clinical use of the BJR (supplement 21) Table of equivalent squares for total scatter factors and phantom scatter related quantities of rectangular fields is
Comparison of 4 analytical techniques based on atomic spectrometry for the determination of total tin in canned foodstuffs

OpenAIRE

2011-01-01

Abstract Different techniques for the determination of total tin in beverage and canned food by atomic spectrometry were compared. The performance characteristics of Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Hydride Generation Inductively Coupled Plasma Atomic Emission Spectrometry (HG-ICP-AES), Electrothermal Atomization Atomic Absorption Spectrometry (ETA-AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) were determined in term of linearity, ...
On the Performance of Maximum Likelihood versus Means and Variance Adjusted Weighted Least Squares Estimation in CFA

Science.gov (United States)

Beauducel, Andre; Herzberg, Philipp Yorck

2006-01-01

This simulation study compared maximum likelihood (ML) estimation with weighted least squares means and variance adjusted (WLSMV) estimation. The study was based on confirmatory factor analyses with 1, 2, 4, and 8 factors, based on 250, 500, 750, and 1,000 cases, and on 5, 10, 20, and 40 variables with 2, 3, 4, 5, and 6 categories. There was no…
Asymptotic behavior of the mean square displacement of the Brownian parametric oscillator near the singular point

International Nuclear Information System (INIS)

Tashiro, Tohru

2009-01-01

A parametric oscillator with damping driven by white noise is studied. The mean square displacement (MSD) in the long-time limit is derived analytically for the case that the static force vanishes, which was not treated in the past work (Tashiro and Morita 2007 Physica A 377 401). The formula is asymptotic but is applicable to a general periodic function. On the basis of this formula, some periodic functions reducing MSD remarkably are proposed
Permutation-invariant distance between atomic configurations

Science.gov (United States)

Ferré, Grégoire; Maillet, Jean-Bernard; Stoltz, Gabriel

2015-09-01

We present a permutation-invariant distance between atomic configurations, defined through a functional representation of atomic positions. This distance enables us to directly compare different atomic environments with an arbitrary number of particles, without going through a space of reduced dimensionality (i.e., fingerprints) as an intermediate step. Moreover, this distance is naturally invariant through permutations of atoms, avoiding the time consuming associated minimization required by other common criteria (like the root mean square distance). Finally, the invariance through global rotations is accounted for by a minimization procedure in the space of rotations solved by Monte Carlo simulated annealing. A formal framework is also introduced, showing that the distance we propose verifies the property of a metric on the space of atomic configurations. Two examples of applications are proposed. The first one consists in evaluating faithfulness of some fingerprints (or descriptors), i.e., their capacity to represent the structural information of a configuration. The second application concerns structural analysis, where our distance proves to be efficient in discriminating different local structures and even classifying their degree of similarity.
Permutation-invariant distance between atomic configurations

International Nuclear Information System (INIS)

Ferré, Grégoire; Maillet, Jean-Bernard; Stoltz, Gabriel

2015-01-01

We present a permutation-invariant distance between atomic configurations, defined through a functional representation of atomic positions. This distance enables us to directly compare different atomic environments with an arbitrary number of particles, without going through a space of reduced dimensionality (i.e., fingerprints) as an intermediate step. Moreover, this distance is naturally invariant through permutations of atoms, avoiding the time consuming associated minimization required by other common criteria (like the root mean square distance). Finally, the invariance through global rotations is accounted for by a minimization procedure in the space of rotations solved by Monte Carlo simulated annealing. A formal framework is also introduced, showing that the distance we propose verifies the property of a metric on the space of atomic configurations. Two examples of applications are proposed. The first one consists in evaluating faithfulness of some fingerprints (or descriptors), i.e., their capacity to represent the structural information of a configuration. The second application concerns structural analysis, where our distance proves to be efficient in discriminating different local structures and even classifying their degree of similarity
The Rydberg constant and proton size from atomic hydrogen

Science.gov (United States)

Beyer, Axel; Maisenbacher, Lothar; Matveev, Arthur; Pohl, Randolf; Khabarova, Ksenia; Grinin, Alexey; Lamour, Tobias; Yost, Dylan C.; Hänsch, Theodor W.; Kolachevsky, Nikolai; Udem, Thomas

2017-10-01

At the core of the “proton radius puzzle” is a four-standard deviation discrepancy between the proton root-mean-square charge radii (rp) determined from the regular hydrogen (H) and the muonic hydrogen (µp) atoms. Using a cryogenic beam of H atoms, we measured the 2S-4P transition frequency in H, yielding the values of the Rydberg constant R∞ = 10973731.568076(96) per meterand rp = 0.8335(95) femtometer. Our rp value is 3.3 combined standard deviations smaller than the previous H world data, but in good agreement with the µp value. We motivate an asymmetric fit function, which eliminates line shifts from quantum interference of neighboring atomic resonances.
Least mean square fourth based microgrid state estimation algorithm using the internet of things technology.

Science.gov (United States)

Rana, Md Masud

2017-01-01

This paper proposes an innovative internet of things (IoT) based communication framework for monitoring microgrid under the condition of packet dropouts in measurements. First of all, the microgrid incorporating the renewable distributed energy resources is represented by a state-space model. The IoT embedded wireless sensor network is adopted to sense the system states. Afterwards, the information is transmitted to the energy management system using the communication network. Finally, the least mean square fourth algorithm is explored for estimating the system states. The effectiveness of the developed approach is verified through numerical simulations.
Investigation of the self tempering effect of martensite by means of atom probe tomography

International Nuclear Information System (INIS)

Sackl, Stephanie; Clemens, Helmut; Primig, Sophie

2015-01-01

Self-tempering effects can be observed in steels with relatively high martensite start temperatures. After the formation of the first martensitic laths, carbon is able to diffuse in these laths during cooling, which can be attributed to sufficiently high temperatures. This effect cannot be observed in laths formed at lower temperatures. In steels containing up to 0.2 m.-% carbon, up to 90 % of the carbon atoms in the martensite segregate to dislocations during quenching. Due to its atomic resolution and sensitivity with respect to light elements, atom probe tomography is very well suited for the investigation of this phenomenon. In this study, the self-tempering effect in a quenched and tempered steel 42CrMo4 with a martensite start temperature of 310 C is investigated by means of atom probe tomography.
A Theoretically Consistent Method for Minimum Mean-Square Error Estimation of Mel-Frequency Cepstral Features

DEFF Research Database (Denmark)

Jensen, Jesper; Tan, Zheng-Hua

2014-01-01

We propose a method for minimum mean-square error (MMSE) estimation of mel-frequency cepstral features for noise robust automatic speech recognition (ASR). The method is based on a minimum number of well-established statistical assumptions; no assumptions are made which are inconsistent with others....... The strength of the proposed method is that it allows MMSE estimation of mel-frequency cepstral coefficients (MFCC's), cepstral mean-subtracted MFCC's (CMS-MFCC's), velocity, and acceleration coefficients. Furthermore, the method is easily modified to take into account other compressive non-linearities than...... the logarithmic which is usually used for MFCC computation. The proposed method shows estimation performance which is identical to or better than state-of-the-art methods. It further shows comparable ASR performance, where the advantage of being able to use mel-frequency speech features based on a power non...
Penalized linear regression for discrete ill-posed problems: A hybrid least-squares and mean-squared error approach

KAUST Repository

Suliman, Mohamed Abdalla Elhag; Ballal, Tarig; Kammoun, Abla; Al-Naffouri, Tareq Y.

2016-01-01

This paper proposes a new approach to find the regularization parameter for linear least-squares discrete ill-posed problems. In the proposed approach, an artificial perturbation matrix with a bounded norm is forced into the discrete ill-posed model
Robust parameterization of elastic and absorptive electron atomic scattering factors

International Nuclear Information System (INIS)

Peng, L.M.; Ren, G.; Dudarev, S.L.; Whelan, M.J.

1996-01-01

A robust algorithm and computer program have been developed for the parameterization of elastic and absorptive electron atomic scattering factors. The algorithm is based on a combined modified simulated-annealing and least-squares method, and the computer program works well for fitting both elastic and absorptive atomic scattering factors with five Gaussians. As an application of this program, the elastic electron atomic scattering factors have been parameterized for all neutral atoms and for s up to 6 A -1 . Error analysis shows that the present results are considerably more accurate than the previous analytical fits in terms of the mean square value of the deviation between the numerical and fitted scattering factors. Parameterization for absorptive atomic scattering factors has been made for 17 important materials with the zinc blende structure over the temperature range 1 to 1000 K, where appropriate, and for temperature ranges for which accurate Debye-Waller factors are available. For other materials, the parameterization of the absorptive electron atomic scattering factors can be made using the program by supplying the atomic number of the element, the Debye-Waller factor and the acceleration voltage. For ions or when more accurate numerical results for neutral atoms are available, the program can read in the numerical values of the elastic scattering factors and return the parameters for both the elastic and absorptive scattering factors. The computer routines developed have been tested both on computer workstations and desktop PC computers, and will be made freely available via electronic mail or on floppy disk upon request. (orig.)
Least mean square fourth based microgrid state estimation algorithm using the internet of things technology.

Directory of Open Access Journals (Sweden)

Md Masud Rana

Full Text Available This paper proposes an innovative internet of things (IoT based communication framework for monitoring microgrid under the condition of packet dropouts in measurements. First of all, the microgrid incorporating the renewable distributed energy resources is represented by a state-space model. The IoT embedded wireless sensor network is adopted to sense the system states. Afterwards, the information is transmitted to the energy management system using the communication network. Finally, the least mean square fourth algorithm is explored for estimating the system states. The effectiveness of the developed approach is verified through numerical simulations.

Terahertz response of fractal meta-atoms based on concentric rectangular square resonators

Energy Technology Data Exchange (ETDEWEB)

Song, Zhiqiang; Zhao, Zhenyu, E-mail: zyzhao@shnu.edu.cn; Shi, Wangzhou [Department of Physics, Shanghai Normal University, Shanghai 200234 (China); Peng, Wei [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

2015-11-21

We investigate the terahertz electromagnetic responses of fractal meta-atoms (MAs) induced by different mode coupling mechanisms. Two types of MAs based on concentric rectangular square (CRS) resonators are presented: independent CRS (I-CRS) and junctional-CRS (J-CRS). In I-CRS, each resonator works as an independent dipole so as to result in the multiple resonance modes when the fractal level is above 1. In J-CRS, however, the generated layer is rotated by π/2 radius to the adjacent CRS in one MA. The multiple resonance modes are coupled into a single mode resonance. The fractal level increasing induces resonance modes redshift in I-CRS while blueshift in J-CRS. When the fractal level is below 4, the mode Q factor of J-CRS is in between the two modes of I-CRS; when the fractal level is 4 or above, the mode Q factor of J-CRS exceeds the two modes of I-CRS. Furthermore, the modulation depth (MD) decreases in I-CRS while it increases in J-CRS with the increase in fractal levels. The surface currents analysis reveals that the capacitive coupling of modes in I-CRS results in the modes redshift, while the conductive coupling of modes in J-CRS induces the mode blueshift. A high Q mode with large MD can be achieved via conductive coupling between the resonators of different scales in a fractal MA.
Unweighted least squares phase unwrapping by means of multigrid techniques

Science.gov (United States)

Pritt, Mark D.

1995-11-01

We present a multigrid algorithm for unweighted least squares phase unwrapping. This algorithm applies Gauss-Seidel relaxation schemes to solve the Poisson equation on smaller, coarser grids and transfers the intermediate results to the finer grids. This approach forms the basis of our multigrid algorithm for weighted least squares phase unwrapping, which is described in a separate paper. The key idea of our multigrid approach is to maintain the partial derivatives of the phase data in separate arrays and to correct these derivatives at the boundaries of the coarser grids. This maintains the boundary conditions necessary for rapid convergence to the correct solution. Although the multigrid algorithm is an iterative algorithm, we demonstrate that it is nearly as fast as the direct Fourier-based method. We also describe how to parallelize the algorithm for execution on a distributed-memory parallel processor computer or a network-cluster of workstations.
Rigorous derivation of the perimeter generating functions for the mean-squared radius of gyration of rectangular, Ferrers and pyramid polygons

International Nuclear Information System (INIS)

Lin, Keh Ying

2006-01-01

We have derived rigorously the perimeter generating functions for the mean-squared radius of gyration of rectangular, Ferrers and pyramid polygons. These functions were found by Jensen recently. His nonrigorous results are based on the analysis of the long series expansions. (comment)
Z-dependence of Mean Excitation Energies for Second and Third Row Atoms and Their Ions

DEFF Research Database (Denmark)

Sauer, Stephan P. A.; Sabin, John R.; Oddershede, Jens

2018-01-01

All mean excitations energies for second and third row atoms and their ions are calculated in the random‐phase approximation using large basis sets. To a very good approximation it turns out that mean excitation energies within an isoelectronic series is a quadratic function of the nuclear charge...
On the generalization of linear least mean squares estimation to quantum systems with non-commutative outputs

Energy Technology Data Exchange (ETDEWEB)

Amini, Nina H. [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States); CNRS, Laboratoire des Signaux et Systemes (L2S) CentraleSupelec, Gif-sur-Yvette (France); Miao, Zibo; Pan, Yu; James, Matthew R. [Australian National University, ARC Centre for Quantum Computation and Communication Technology, Research School of Engineering, Canberra, ACT (Australia); Mabuchi, Hideo [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States)

2015-12-15

The purpose of this paper is to study the problem of generalizing the Belavkin-Kalman filter to the case where the classical measurement signal is replaced by a fully quantum non-commutative output signal. We formulate a least mean squares estimation problem that involves a non-commutative system as the filter processing the non-commutative output signal. We solve this estimation problem within the framework of non-commutative probability. Also, we find the necessary and sufficient conditions which make these non-commutative estimators physically realizable. These conditions are restrictive in practice. (orig.)
Role and significance of total phenols during rooting of Protea ...

African Journals Online (AJOL)

Reviewer

2011-10-03

Oct 3, 2011 ... fluctuations in total phenol concentration of different parts ... Rooting percentage, mean root dry mass and mean number of roots according to root length ... differences at P ≤ 0.05 based on chi-square; 2different letters in.
Hirshfeld atom refinement.

Science.gov (United States)

Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

2014-09-01

Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.
Self-Regular Black Holes Quantized by means of an Analogue to Hydrogen Atoms

Directory of Open Access Journals (Sweden)

Chang Liu

2016-01-01

Full Text Available We suggest a quantum black hole model that is based on an analogue to hydrogen atoms. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of nonextreme black holes are given by the probability densities of excited states with no angular momenta. Such an analogue is inclined to adopt quantization of black hole horizons. In this way, the total mass of black holes is quantized. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Magnetic-film atom chip with 10 μm period lattices of microtraps for quantum information science with Rydberg atoms.

Science.gov (United States)

Leung, V Y F; Pijn, D R M; Schlatter, H; Torralbo-Campo, L; La Rooij, A L; Mulder, G B; Naber, J; Soudijn, M L; Tauschinsky, A; Abarbanel, C; Hadad, B; Golan, E; Folman, R; Spreeuw, R J C

2014-05-01

We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 μm, suitable for experiments in quantum information science employing the interaction between atoms in highly excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cutout of a silver foil, was mounted under the atom chip in order to load ultracold (87)Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.
Magnetic-film atom chip with 10 μm period lattices of microtraps for quantum information science with Rydberg atoms

Energy Technology Data Exchange (ETDEWEB)

Leung, V. Y. F. [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands); Complex Photonic Systems (COPS), MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Pijn, D. R. M.; Schlatter, H.; Torralbo-Campo, L.; La Rooij, A. L.; Mulder, G. B.; Naber, J.; Soudijn, M. L.; Tauschinsky, A.; Spreeuw, R. J. C., E-mail: r.j.c.spreeuw@uva.nl [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands); Abarbanel, C.; Hadad, B.; Golan, E. [Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be' er Sheva 84105 (Israel); Folman, R. [Department of Physics and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be' er Sheva 84105 (Israel)

2014-05-15

We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 μm, suitable for experiments in quantum information science employing the interaction between atoms in highly excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cutout of a silver foil, was mounted under the atom chip in order to load ultracold {sup 87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.
Study of total ionization by {alpha} particles, in pure gases and gaseous mixtures containing metastable atoms, as a function of temperature; Etude de l'ionisation totale par les paricules {alpha}, dans les gaz purs et les melanges gazeux contenant des atomes metastables, en fonction de la temperature

Energy Technology Data Exchange (ETDEWEB)

Bristeau, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Experiments have been carried out on the total ionization by alpha particles, in pure gases and gaseous mixtures containing metastable atoms, as a function of temperature. Using a different experimental method, the results for the mean ionization energy at 300 K given by Jesse in 1953 have been confirmed to within 1 per cent. It is established that in pure gases the mean energy W required to form a pair of ions remains constant as the temperature varies from 77 to 300 K. It is shown that there is a temperature effect for W in binary gas mixtures of the type A-B containing meta-stable atoms A{sup *} and an 'impurity' B. A systematic study is made of the change {delta}W in W as a function of the temperature and of the B 'impurity' concentration in the mixtures Ne - Ar, Ne - Kr, Ne - H{sub 2}, Ne - N{sub 2}, Ne - CH{sub 4} and He - Ar. Experiments have been carried out on a ternary gas mixture of the type A - B - C, where C is a second ionizable 'impurity' added to the binary mixture A - B; they show the existence of excited atoms B{sup *} formed from the 'impurity' B. Finally, it is shown that the amount of metastable atoms formed in a pure gas must be very close to the number N{sub 0} of ion pairs, and that there must exist a correlation between the number N{sub 0} of ion pairs and the number {approx_equal} N{sub 0} of metastable atoms created in the pure rare gases. (author) [French] On realise des experiences sur l'ionisation totale par les particules alpha, dans les gaz purs et les melanges gazeux contenant des atomes metastables, en fonction de la temperature. Avec une methode experimentale differente, on retrouve a mieux que 1 pour cent pres les valeurs de l'energie moyenne d'ionisation que JESSE a obtenues en 1953 et a 300 K. On etablit que dans les gaz purs, l'energie moyenne W pour creer une paire d'ions demeure constante, quand la temperature varie entre 77 et 300 K. On met en evidence un effet de temperature sur W, dans les melanges gazeux binaires du type
Petroleomics by electrospray ionization FT-ICR mass spectrometry coupled to partial least squares with variable selection methods: prediction of the total acid number of crude oils.

Science.gov (United States)

Terra, Luciana A; Filgueiras, Paulo R; Tose, Lílian V; Romão, Wanderson; de Souza, Douglas D; de Castro, Eustáquio V R; de Oliveira, Mirela S L; Dias, Júlio C M; Poppi, Ronei J

2014-10-07

Negative-ion mode electrospray ionization, ESI(-), with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was coupled to a Partial Least Squares (PLS) regression and variable selection methods to estimate the total acid number (TAN) of Brazilian crude oil samples. Generally, ESI(-)-FT-ICR mass spectra present a power of resolution of ca. 500,000 and a mass accuracy less than 1 ppm, producing a data matrix containing over 5700 variables per sample. These variables correspond to heteroatom-containing species detected as deprotonated molecules, [M - H](-) ions, which are identified primarily as naphthenic acids, phenols and carbazole analog species. The TAN values for all samples ranged from 0.06 to 3.61 mg of KOH g(-1). To facilitate the spectral interpretation, three methods of variable selection were studied: variable importance in the projection (VIP), interval partial least squares (iPLS) and elimination of uninformative variables (UVE). The UVE method seems to be more appropriate for selecting important variables, reducing the dimension of the variables to 183 and producing a root mean square error of prediction of 0.32 mg of KOH g(-1). By reducing the size of the data, it was possible to relate the selected variables with their corresponding molecular formulas, thus identifying the main chemical species responsible for the TAN values.
Spreading Sequence Design for Multiple Cell Synchronous DS-CDMA Systems under Total Weighted Squared Correlation Criterion

Directory of Open Access Journals (Sweden)

Cotae Paul

2004-01-01

Full Text Available An algorithm for designing spreading sequences for an overloaded multicellular synchronous DS-CDMA system on uplink is introduced. The criterion used to measure the optimality of the design is the total weighted square correlation (TWSC assuming the channel state information known perfectly at both transmitter and receiver. By using this algorithm it is possible to obtain orthogonal generalized WBE sequences sets for any processing gain. The bandwidth of initial generalized WBE signals of each cell is preserved in the extended signal space associated to multicellular system. Mathematical formalism is illustrated by selected numerical examples.
The effect of atom mismatch on the fragility of supercooled Lennard-Jones binary mixtures

International Nuclear Information System (INIS)

Sun Minhua; Sun Yongli; Wang Aiping; Ma Congxiao; Li Jiayun; Cheng Weidong; Liu Fang

2006-01-01

The shear viscosity of the well-known binary Lennard-Jones mixture is simulated under constant temperature and constant volume conditions (NVT) by a molecular-dynamics (MD) method. The effect of atomic size mismatch on the fragility parameter and glass-forming ability is studied. The fragility parameters calculated from shear viscosity data decrease with the increment of the atomic size mismatch. The value of the fragility changes from 168.963 to 22.976 when the mismatch changes from 0.023 to 0.25. It is shown that the fragility parameter is sensitive to the atomic size mismatch. The calculated pair distribution functions and mean square displacements indicate that the glass-forming ability increases with the atomic size mismatch
Orbital and total atomic momentum expectation values with Roothaan-Hartree-Fock wave functions

International Nuclear Information System (INIS)

De La Vega, J.M.G.; Miguel, B.

1993-01-01

Orbital and total momentum expectation values are computed using the Roothaan-Hartree-Fock wave functions of Clementi and Roetti. These values are calculated analytically and may be used to study the quality of basis sets. Tabulations for ground and excited states of atoms from Z = 2 to Z = 54 are presented. 23 refs., 1 tab
X-ray determination of mean square amplitudes of lattice oscillations in compounds with ZnS structure

International Nuclear Information System (INIS)

Deus, P.; Schneider, H.A.; Voland, U.

1980-01-01

A general method of determination of the mean square amplitudes of lattice oscillations (MSA) for crystals with sphalerite structure is described and applied to InP. The linearity of suitable functions of the measured integral BRAGG intensities of sin 2 theta/lambda 2 is used for the verification of the parameters selected for the correction of extinction and DTS. In this way the accuracy of the results is increased. The MSAs of the InP-sublattices are evaluated. According to theoretical expectations the MSAs of the P-sublattice are larger because of the greater contributions of optical phonons. (author)
Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles

Science.gov (United States)

Ingebo, R. D.

1977-01-01

A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.
XAFS study of copper(II) complexes with square planar and square pyramidal coordination geometries

Science.gov (United States)

Gaur, A.; Klysubun, W.; Nitin Nair, N.; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

2016-08-01

X-ray absorption fine structure of six Cu(II) complexes, Cu2(Clna)4 2H2O (1), Cu2(ac)4 2H2O (2), Cu2(phac)4 (pyz) (3), Cu2(bpy)2(na)2 H2O (ClO4) (4), Cu2(teen)4(OH)2(ClO4)2 (5) and Cu2(tmen)4(OH)2(ClO4)2 (6) (where ac, phac, pyz, bpy, na, teen, tmen = acetate, phenyl acetate, pyrazole, bipyridine, nicotinic acid, tetraethyethylenediamine, tetramethylethylenediamine, respectively), which were supposed to have square pyramidal and square planar coordination geometries have been investigated. The differences observed in the X-ray absorption near edge structure (XANES) features of the standard compounds having four, five and six coordination geometry points towards presence of square planar and square pyramidal geometry around Cu centre in the studied complexes. The presence of intense pre-edge feature in the spectra of four complexes, 1-4, indicates square pyramidal coordination. Another important XANES feature, present in complexes 5 and 6, is prominent shoulder in the rising part of edge whose intensity decreases in the presence of axial ligands and thus indicates four coordination in these complexes. Ab initio calculations were carried out for square planar and square pyramidal Cu centres to observe the variation of 4p density of states in the presence and absence of axial ligands. To determine the number and distance of scattering atoms around Cu centre in the complexes, EXAFS analysis has been done using the paths obtained from Cu(II) oxide model and an axial Cu-O path from model of a square pyramidal complex. The results obtained from EXAFS analysis have been reported which confirmed the inference drawn from XANES features. Thus, it has been shown that these paths from model of a standard compound can be used to determine the structural parameters for complexes having unknown structure.
Enumeration of self-avoiding walks on the square lattice

International Nuclear Information System (INIS)

Jensen, Iwan

2004-01-01

We describe a new algorithm for the enumeration of self-avoiding walks on the square lattice. Using up to 128 processors on a HP Alpha server cluster we have enumerated the number of self-avoiding walks on the square lattice to length 71. Series for the metric properties of mean-square end-to-end distance, mean-square radius of gyration and mean-square distance of monomers from the end points have been derived to length 59. An analysis of the resulting series yields accurate estimates of the critical exponents γ and ν confirming predictions of their exact values. Likewise we obtain accurate amplitude estimates yielding precise values for certain universal amplitude combinations. Finally we report on an analysis giving compelling evidence that the leading non-analytic correction-to-scaling exponent Δ 1 = 3/2
Determination of the root-mean-square radius of the deuteron from present-day experimental data on neutron-proton scattering

International Nuclear Information System (INIS)

Babenko, V. A.; Petrov, N. M.

2008-01-01

The correlation between the root-mean-square matter radius of the deuteron, r m , and its effective radius, ρ, is investigated. A parabolic relationship between these two quantities makes it possible to determine the root-mean-square radius r m to within 0.01% if the effective radius ρ is known. The matter (r m ), structural (r d ), and charge (r ch ) radii of the deuteron are found with the aid of modern experimental results for phase shifts from the SAID nucleon-nucleon database, and their values are fully consistent with their counterparts deduced by using the experimental value of the effective deuteron radius due to Borbely and his coauthors. The charge-radius value of 2.124(6) fm, which was obtained with the aid of the SAID nucleon-nucleon database, and the charge-radius value of 2.126(12) fm, which was obtained with the aid of the experimental value of the effective radius ρ, are in very good agreement with the present-day chargeradius value of 2.128(11) fm, which was deduced by Sick and Trautmann by processing world-average experimental data on elastic electron scattering by deuterons with allowance for Coulomb distortions.

Generalized quantum mean-field systems and their application to ultracold atoms

International Nuclear Information System (INIS)

Trimborn-Witthaut, Friederike Annemarie

2011-01-01

Strongly interacting many-body systems consisting of a large number of indistinguishable particles play an important role in many areas of physics. Though such systems are hard to deal with theoretically since the dimension of the respective Hilbert space increases exponentially both in the particle number and in the number of system modes. Therefore, approximations are of considerable interest. The mean-field approximation describes the behaviour in the macroscopic limit N→∞, which leads to an effective nonlinear single-particle problem. Although this approximation is widely used, rigorous results on the applicability and especially on finite size corrections are extremely rare. One prominent example of strongly interacting many-body systems are ultracold atoms in optical lattices, which are a major subject of this thesis. Typically these systems consist of a large but well-defined number of particles, such that corrections to the mean-field limit can be systematically studied. This thesis is divided into two parts: In the first part we study generalized quantum mean-field systems in a C * -algebraic framework. These systems are characterized by their intrinsic permutation symmetry. In the limit of infinite system size, N→∞, the intensive observables converge to the commutative algebra of weak * -continuous functions on the single particle state space. To quantify the deviations from the meanfield prediction for large but finite N, we establish a differential calculus for state space functions and provide a generalized Taylor expansion around the mean-field limit. Furthermore, we introduce the algebra of macroscopic fluctuations around the mean-field limit and prove a quantum version of the central limit theorem. On the basis of these results, we give a detailed study of the finite size corrections to the ground state energy and establish bounds, for both the quantum and the classical case. Finally, we restrict ourselves to the subspace of Bose
DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION

Science.gov (United States)

A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...
Statistical properties of the anomalous scaling exponent estimator based on time-averaged mean-square displacement

Science.gov (United States)

Sikora, Grzegorz; Teuerle, Marek; Wyłomańska, Agnieszka; Grebenkov, Denis

2017-08-01

The most common way of estimating the anomalous scaling exponent from single-particle trajectories consists of a linear fit of the dependence of the time-averaged mean-square displacement on the lag time at the log-log scale. We investigate the statistical properties of this estimator in the case of fractional Brownian motion (FBM). We determine the mean value, the variance, and the distribution of the estimator. Our theoretical results are confirmed by Monte Carlo simulations. In the limit of long trajectories, the estimator is shown to be asymptotically unbiased, consistent, and with vanishing variance. These properties ensure an accurate estimation of the scaling exponent even from a single (long enough) trajectory. As a consequence, we prove that the usual way to estimate the diffusion exponent of FBM is correct from the statistical point of view. Moreover, the knowledge of the estimator distribution is the first step toward new statistical tests of FBM and toward a more reliable interpretation of the experimental histograms of scaling exponents in microbiology.
Inelastic collisions of atomic particles at mean energies. Pt.1. Qualitative model of energy losses during a collision

International Nuclear Information System (INIS)

Pustovit, A.N.

2005-01-01

A new approach is proposed for description of the energy losses of mean-energy atomic particles during their interactions with atomic particles of solids. It is shown that all these interactions are inelastic ones and are determined by different scattering zones with different laws of energy loss dependences [ru
Atomic structure of non-stoichiometric transition metal carbides

International Nuclear Information System (INIS)

Moisy-Maurice, Virginie.

1981-10-01

Different kinds of experimental studies of the atomic arrangement in non-stoichiometric transition metal carbides are proposed: the ordering of carbon vacancies and the atomic static displacements are the main subjects studied. Powder neutron diffraction on TiCsub(1-x) allowed us to determine the order-disorder transition critical temperature -Tsub(c) approximately 770 0 C- in the TiCsub(0.52-0.67) range, and to analyze at 300 K the crystal structure of long-range ordered samples. A neutron diffuse scattering quantitative study at 300 K of short-range order in TiCsub(0.76), TiCsub(0.79) and NbCsub(0.73) single crystals is presented: as in Ti 2 Csub(1+x) and Nb 6 C 5 superstructures, vacancies avoid to be on each side of a metal atom. Besides, the mean-square carbon atom displacements from their sites are small, whereas metal atoms move radially about 0.03 A away from vacancies. These results are in qualitative agreement with EXAFS measurements at titanium-K edge of TiCsub(1-x). An interpretation of ordering in term of short-range interaction pair potentials between vacancies is proposed [fr
Partial update least-square adaptive filtering

CERN Document Server

Xie, Bei

2014-01-01

Adaptive filters play an important role in the fields related to digital signal processing and communication, such as system identification, noise cancellation, channel equalization, and beamforming. In practical applications, the computational complexity of an adaptive filter is an important consideration. The Least Mean Square (LMS) algorithm is widely used because of its low computational complexity (O(N)) and simplicity in implementation. The least squares algorithms, such as Recursive Least Squares (RLS), Conjugate Gradient (CG), and Euclidean Direction Search (EDS), can converge faster a
Mean square hydrogen fluctuations in chitosan/lecithin nanoparticles from elastic neutron scattering experiments

Science.gov (United States)

Sonvico, Fabio; Teresa Di Bari, Maria; Bove, Livia; Deriu, Antonio; Cavatorta, Fabrizio; Albanese, Gianfranco

2006-11-01

Recently, we have started a systematic study of the structure and dynamics of nano- and microparticles of interest as highly biocompatible drug carriers. For these particles, that are composed of polymeric and lipid material, a detailed understanding of the particle-solvent interactions is of key importance in order to tailor their characteristics for delivering drugs with specific chemical properties. Here we report results of elastic neutron scattering (ENS) investigations on lecithin/chitosan nanoparticles. They were first prepared by autoassembling the two components in aqueous solution; the samples were then freeze-dried and re-hydrated in a D 2O atmosphere. The experiments were performed in the temperature range of 20-50 K using the backscattering spectrometer IN13 at ILL (Grenoble, France). The comparison of samples in the dry state with similar ones at an hydration level of about 0.3-0.4 (g D 2O/g hydrated sample), indicates that the presence of an outer chitosan ‘‘coating’’ reduces the mean square fluctuations of the hydrogens in the lipid component, leading thus to a stiffer nanoparticle structure.
Microfabricated Waveguide Atom Traps.

Energy Technology Data Exchange (ETDEWEB)

Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.
Inversion of the total cross sections for electron-molecule and electron-atom scattering

International Nuclear Information System (INIS)

Lun, D.R.; Amos, K.; Allen, L.J.

1994-01-01

Inverse scattering theory has been applied to construct the interaction potentials from total cross sections as a function of energy for electrons scattered off of atoms and molecules. The underlying potentials are assumed to be real and energy independent and are evaluated using the Eikonal approximation and with real phase shifts determined from the total cross sections. The inversion potentials have been determined using either a high energy limit approximation or by using a fixed energy inversion method at select energies. These procedures have been used to analyse e - - CH 4 , e - - SiH 4 , e - -Kr and e - -Xe scattering data in particular. 14 refs., 1 tabs., 3 figs
Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses.

Science.gov (United States)

Lorenz, Kathrine Osborn; Kakkassery, Joseph; Boree, Danielle; Pinto, David

2014-09-01

Limbal ring (also known as 'circle') contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or 'enclosed' within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of 'circle' contact lenses. Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 μm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance. © 2014 The Authors. Clinical and Experimental
On the validity of classical description of scattering of atomic particles at mean energies

International Nuclear Information System (INIS)

Pustovit, A.N.

2004-01-01

The conditions of applicability of the classical theory of atomic particle scattering to the small angle and quasi-small angle approximations in calculations of mean-energy particle deflection angles using power interaction potential are analyzed. The applicability range is shown to be much widened for the quasi-small angle approximation, extending to the ranges of quantum theory applicability [ru
Connection between fragility, mean-squared displacement and shear modulus in two van der Waals bonded glass-forming liquids

DEFF Research Database (Denmark)

Hansen, Henriette Wase; Frick, Bernhard; Hecksher, Tina

2017-01-01

The temperature dependence of the high-frequency shear modulus measured in the kHz range is compared with the mean-squared displacement measured in the nanosecond range for the two van der Waals bonded glass-forming liquids cumene and 5-polyphenyl ether. This provides an experimental test for the...... for the assumption connecting two versions of the shoving model for the non-Arrhenius temperature dependence of the relaxation time in glass formers. The two versions of the model are also tested directly and both are shown to work well for these liquids....
Atom-by-atom assembly

International Nuclear Information System (INIS)

Hla, Saw Wai

2014-01-01

Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed. (review article)
Improved linear least squares estimation using bounded data uncertainty

KAUST Repository

Ballal, Tarig

2015-04-01

This paper addresses the problemof linear least squares (LS) estimation of a vector x from linearly related observations. In spite of being unbiased, the original LS estimator suffers from high mean squared error, especially at low signal-to-noise ratios. The mean squared error (MSE) of the LS estimator can be improved by introducing some form of regularization based on certain constraints. We propose an improved LS (ILS) estimator that approximately minimizes the MSE, without imposing any constraints. To achieve this, we allow for perturbation in the measurement matrix. Then we utilize a bounded data uncertainty (BDU) framework to derive a simple iterative procedure to estimate the regularization parameter. Numerical results demonstrate that the proposed BDU-ILS estimator is superior to the original LS estimator, and it converges to the best linear estimator, the linear-minimum-mean-squared error estimator (LMMSE), when the elements of x are statistically white.
Improved linear least squares estimation using bounded data uncertainty

KAUST Repository

Ballal, Tarig; Al-Naffouri, Tareq Y.

2015-01-01

This paper addresses the problemof linear least squares (LS) estimation of a vector x from linearly related observations. In spite of being unbiased, the original LS estimator suffers from high mean squared error, especially at low signal-to-noise ratios. The mean squared error (MSE) of the LS estimator can be improved by introducing some form of regularization based on certain constraints. We propose an improved LS (ILS) estimator that approximately minimizes the MSE, without imposing any constraints. To achieve this, we allow for perturbation in the measurement matrix. Then we utilize a bounded data uncertainty (BDU) framework to derive a simple iterative procedure to estimate the regularization parameter. Numerical results demonstrate that the proposed BDU-ILS estimator is superior to the original LS estimator, and it converges to the best linear estimator, the linear-minimum-mean-squared error estimator (LMMSE), when the elements of x are statistically white.
xGASS: total cold gas scaling relations and molecular-to-atomic gas ratios of galaxies in the local Universe

Science.gov (United States)

Catinella, Barbara; Saintonge, Amélie; Janowiecki, Steven; Cortese, Luca; Davé, Romeel; Lemonias, Jenna J.; Cooper, Andrew P.; Schiminovich, David; Hummels, Cameron B.; Fabello, Silvia; Geréb, Katinka; Kilborn, Virginia; Wang, Jing

2018-05-01

We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic hydrogen (H I) gas content of 1179 galaxies selected only by stellar mass (M⋆ = 109-1011.5 M⊙) and redshift (0.01 new Arecibo observations of 208 galaxies, for which we release catalogues and H I spectra. In addition to extending the GASS H I scaling relations by one decade in stellar mass, we quantify total (atomic+molecular) cold gas fractions and molecular-to-atomic gas mass ratios, Rmol, for the subset of 477 galaxies observed with the IRAM 30 m telescope. We find that atomic gas fractions keep increasing with decreasing stellar mass, with no sign of a plateau down to log M⋆/M⊙ = 9. Total gas reservoirs remain H I-dominated across our full stellar mass range, hence total gas fraction scaling relations closely resemble atomic ones, but with a scatter that strongly correlates with Rmol, especially at fixed specific star formation rate. On average, Rmol weakly increases with stellar mass and stellar surface density μ⋆, but individual values vary by almost two orders of magnitude at fixed M⋆ or μ⋆. We show that, for galaxies on the star-forming sequence, variations of Rmol are mostly driven by changes of the H I reservoirs, with a clear dependence on μ⋆. Establishing if galaxy mass or structure plays the most important role in regulating the cold gas content of galaxies requires an accurate separation of bulge and disc components for the study of gas scaling relations.
Quantum atom-heteronuclear molecule dark state: Role of population imbalance

International Nuclear Information System (INIS)

Jing Hui; Cui Shuai

2010-01-01

Recently, the finite-number effect of initial atoms in coherent atom-molecule conversion was investigated by Zhao et al. [Phys. Rev. Lett. 101, 010401 (2008)]. Here, by extending to the atom-heteronuclear molecule dark state, we find that the initial populations imbalance of the atoms plays a significant role in quantum conversion rate and adiabatic fidelity. In particular, even for the finite total number of imbalanced two-species atoms, the mean-field conversion rate, contrary to the general belief, still can be remarkably close to the exact quantum results.
The Total Least Squares Problem in AX approximate to B: A New Classification with the Relationship to the Classical Works

Czech Academy of Sciences Publication Activity Database

Hnětynková, I.; Plešinger, Martin; Sima, D.M.; Strakoš, Z.; Huffel van, S.

2011-01-01

Roč. 32, č. 3 (2011), s. 748-770 ISSN 0895-4798 R&D Projects: GA AV ČR IAA100300802 Grant - others:GA ČR(CZ) GA201/09/0917 Program:GA Institutional research plan: CEZ:AV0Z10300504 Keywords : total least squares * multiple right-hand sides * linear approximation problems * orthogonally invariant problems * orthogonal regression * errors-in-variables modeling Subject RIV: BA - General Mathematics Impact factor: 1.368, year: 2011
Momentum diffusion for coupled atom-cavity oscillators

International Nuclear Information System (INIS)

Murr, K.; Maunz, P.; Pinkse, P. W. H.; Puppe, T.; Schuster, I.; Rempe, G.; Vitali, D.

2006-01-01

It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum diffusion, which is valid for most configurations of interest: The atom or the cavity or both can be probed by lasers, with or without the presence of traps inducing local atomic frequency shifts. It is shown that, albeit the (possibly strong) coupling between atom and cavity, it is sufficient for deriving the momentum diffusion to consider that the atom couples to a mean cavity field, which gives a first contribution, and that the cavity mode couples to a mean atomic dipole, giving a second contribution. Both contributions have an intuitive form and present a clear symmetry. The total diffusion is the sum of these two contributions plus the diffusion originating from the fluctuations of the forces due to the coupling to the vacuum modes other than the cavity mode (the so-called spontaneous emission term). Examples are given that help to evaluate the heating rates induced by an optical cavity for experiments operating at low atomic saturation. We also point out intriguing situations where the atom is heated although it cannot scatter light
Pionic atoms, the relativistic mean-field theory and the pion-nucleon scattering lenghts

International Nuclear Information System (INIS)

Goudsmit, P.F.A.; Leisi, H.J.; Matsinos, E.

1991-01-01

Analysing pionic-atom data of isoscalar nuclei within the relativistic mean-field (RMF) theory, we determine the pseudoscalar πNN mixing parameter x=0.24±0.06 (syst.) and the strength of the nuclear scalar meson field for pions, S π =-34±14 (syst.) MeV. We show that these values are compatible with the elementary π-N interaction. Our RMF model provides a solution to the long-standing problem of the s-wave repulsion. (orig.)

Atomic spectroscopy study of nuclear properties of francium and cesium isotopes; Etude par spectroscopie atomique de proprietes nucleaires d'isotopes de francium et de cesium

Energy Technology Data Exchange (ETDEWEB)

Coc, A

1986-04-15

This work is based on the study of cesium ({sup 118,146}Cs) and francium ({sup 207-213}Fr,{sup 220-228}Fr) isotopes by hyperfine atomic spectroscopy and on the interpretation of these results from the nuclear physics point of view. The measured nuclear quantities are: the spin, the magnetic moment, the electric quadrupole moment and the mean square charge radius. The experimental method which is based on hyperfine optical pumping with a tunable laser, followed by magnetic analysis of the atoms is described in the first part. Results related to atomic physics are also presented. In the second part, these data are interpreted in the framework of nuclear models. The deformation of light cesium isomers are compared to values obtained from a theoretical self-consistent calculation. Heavy francium isotopes are situated in an area where the existence of static octupole deformations have been predicted. The odd-even staggering measured on the mean square radius is abnormal in this region. However, on the basis of experimental data, no definitive conclusion can be drawn regarding the nature of these deformations. (author)
Robust Least-Squares Support Vector Machine With Minimization of Mean and Variance of Modeling Error.

Science.gov (United States)

Lu, Xinjiang; Liu, Wenbo; Zhou, Chuang; Huang, Minghui

2017-06-13

The least-squares support vector machine (LS-SVM) is a popular data-driven modeling method and has been successfully applied to a wide range of applications. However, it has some disadvantages, including being ineffective at handling non-Gaussian noise as well as being sensitive to outliers. In this paper, a robust LS-SVM method is proposed and is shown to have more reliable performance when modeling a nonlinear system under conditions where Gaussian or non-Gaussian noise is present. The construction of a new objective function allows for a reduction of the mean of the modeling error as well as the minimization of its variance, and it does not constrain the mean of the modeling error to zero. This differs from the traditional LS-SVM, which uses a worst-case scenario approach in order to minimize the modeling error and constrains the mean of the modeling error to zero. In doing so, the proposed method takes the modeling error distribution information into consideration and is thus less conservative and more robust in regards to random noise. A solving method is then developed in order to determine the optimal parameters for the proposed robust LS-SVM. An additional analysis indicates that the proposed LS-SVM gives a smaller weight to a large-error training sample and a larger weight to a small-error training sample, and is thus more robust than the traditional LS-SVM. The effectiveness of the proposed robust LS-SVM is demonstrated using both artificial and real life cases.
Experimental root mean square charge radii, isotope shifts, ground state magnetic dipole and electric quadrupole moments of 1≤A≤ 239 nuclei

International Nuclear Information System (INIS)

Antony, M.S.; Britz, J.

1986-01-01

A compilation of experimental root-mean square radii, isotope shifts, ground-state magnetic dipole and electric quadrupole moments of nuclei 1≤A≤239 is presented. Shell, sub-subshell closures and changes in nuclear deformations discernible from data are displayed graphically. The nuclear charge distribution, for 1≤A≤ 239 nuclei deduced from Coulomb displacement energies is shown for comparison
Atomic spectroscopy study of nuclear properties of francium and cesium isotopes; Etude par spectroscopie atomique de proprietes nucleaires d'isotopes de francium et de cesium

Energy Technology Data Exchange (ETDEWEB)

Coc, A

1986-04-15

This work is based on the study of cesium ({sup 118,146}Cs) and francium ({sup 207-213}Fr,{sup 220-228}Fr) isotopes by hyperfine atomic spectroscopy and on the interpretation of these results from the nuclear physics point of view. The measured nuclear quantities are: the spin, the magnetic moment, the electric quadrupole moment and the mean square charge radius. The experimental method which is based on hyperfine optical pumping with a tunable laser, followed by magnetic analysis of the atoms is described in the first part. Results related to atomic physics are also presented. In the second part, these data are interpreted in the framework of nuclear models. The deformation of light cesium isomers are compared to values obtained from a theoretical self-consistent calculation. Heavy francium isotopes are situated in an area where the existence of static octupole deformations have been predicted. The odd-even staggering measured on the mean square radius is abnormal in this region. However, on the basis of experimental data, no definitive conclusion can be drawn regarding the nature of these deformations. (author)
Multipolar electrostatics for proteins: atom-atom electrostatic energies in crambin.

Science.gov (United States)

Yuan, Yongna; Mills, Matthew J L; Popelier, Paul L A

2014-02-15

Accurate electrostatics necessitates the use of multipole moments centered on nuclei or extra point charges centered away from the nuclei. Here, we follow the former alternative and investigate the convergence behavior of atom-atom electrostatic interactions in the pilot protein crambin. Amino acids are cut out from a Protein Data Bank structure of crambin, as single amino acids, di, or tripeptides, and are then capped with a peptide bond at each side. The atoms in the amino acids are defined through Quantum Chemical Topology (QCT) as finite volume electron density fragments. Atom-atom electrostatic energies are computed by means of a multipole expansion with regular spherical harmonics, up to a total interaction rank of L = ℓA+ ℓB + 1 = 10. The minimum internuclear distance in the convergent region of all the 15 possible types of atom-atom interactions in crambin that were calculated based on single amino acids are close to the values calculated from di and tripeptides. Values obtained at B3LYP/aug-cc-pVTZ and MP2/aug-cc-pVTZ levels are only slightly larger than those calculated at HF/6-31G(d,p) level. This convergence behavior is transferable to the well-known amyloid beta polypeptide Aβ1-42. Moreover, for a selected central atom, the influence of its neighbors on its multipole moments is investigated, and how far away this influence can be ignored is also determined. Finally, the convergence behavior of AMBER becomes closer to that of QCT with increasing internuclear distance. Copyright © 2013 Wiley Periodicals, Inc.
Progress in atomizing high melting intermetallic titanium based alloys by means of a novel plasma melting induction guiding gas atomization facility (PIGA)

Energy Technology Data Exchange (ETDEWEB)

Gerling, R.; Schimansky, F.P.; Wagner, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

1994-12-31

For the production of intermetallic titanium based alloy powders a novel gas atomization facility has been put into operation: By means of a plasma torch the alloy is melted in a water cooled copper crucible in skull melting technique. To the tap hole of the crucible, a novel transfer system is mounted which forms a thin melt stream and guides it into the gas nozzle. This transfer system consists of a ceramic free induction heated water cooled copper funnel. Gas atomization of {gamma}-TiAl (melting temperature 1400 C) and Ti{sub 5}Si{sub 3} (2130 C) proved the possibility to produce ceramic free pre-alloyed powders with this novel facility. The TiAl powder particles are spherical; about 20 wt.% are smaller than 45 {mu}m. The oxygen and copper pick up during atomization do not exceed 250 and 35 {mu}g/g respectively. The Ti{sub 5}Si{sub 3} powder particles are almost spherical. Only about 10 wt.% are <45 {mu}m whereas the O{sub 2} and Cu contamination is also kept at a very low level (250 and 20 {mu}g/g respectively). (orig.)
Prediction of octanol-water partition coefficients of organic compounds by multiple linear regression, partial least squares, and artificial neural network.

Science.gov (United States)

Golmohammadi, Hassan

2009-11-30

A quantitative structure-property relationship (QSPR) study was performed to develop models those relate the structure of 141 organic compounds to their octanol-water partition coefficients (log P(o/w)). A genetic algorithm was applied as a variable selection tool. Modeling of log P(o/w) of these compounds as a function of theoretically derived descriptors was established by multiple linear regression (MLR), partial least squares (PLS), and artificial neural network (ANN). The best selected descriptors that appear in the models are: atomic charge weighted partial positively charged surface area (PPSA-3), fractional atomic charge weighted partial positive surface area (FPSA-3), minimum atomic partial charge (Qmin), molecular volume (MV), total dipole moment of molecule (mu), maximum antibonding contribution of a molecule orbital in the molecule (MAC), and maximum free valency of a C atom in the molecule (MFV). The result obtained showed the ability of developed artificial neural network to prediction of partition coefficients of organic compounds. Also, the results revealed the superiority of ANN over the MLR and PLS models. Copyright 2009 Wiley Periodicals, Inc.
Partial and total electronic stopping cross sections of atoms for a singly charged helium ion, Part 2

International Nuclear Information System (INIS)

Kaneko, T.; Nishikori, M.; Yamato, N.

1991-08-01

Partial and total electronic stopping cross sections of atoms with Z (55 ≤ Z ≤ 92) for a He + ion are tabulated as the second part of NIFS-DATA-11 (1991) on the basis of the wave-packet theory. (author)
Construction of a Mean Square Error Adaptive Euler–Maruyama Method With Applications in Multilevel Monte Carlo

KAUST Repository

Hoel, Hakon

2016-06-13

A formal mean square error expansion (MSE) is derived for Euler-Maruyama numerical solutions of stochastic differential equations (SDE). The error expansion is used to construct a pathwise, a posteriori, adaptive time-stepping Euler-Maruyama algorithm for numerical solutions of SDE, and the resulting algorithm is incorporated into a multilevel Monte Carlo (MLMC) algorithm for weak approximations of SDE. This gives an efficient MSE adaptive MLMC algorithm for handling a number of low-regularity approximation problems. In low-regularity numerical example problems, the developed adaptive MLMC algorithm is shown to outperform the uniform time-stepping MLMC algorithm by orders of magnitude, producing output whose error with high probability is bounded by TOL > 0 at the near-optimal MLMC cost rate б(TOL log(TOL)) that is achieved when the cost of sample generation is б(1).
Over-Sampling Codebook-Based Hybrid Minimum Sum-Mean-Square-Error Precoding for Millimeter-Wave 3D-MIMO

KAUST Repository

Mao, Jiening

2018-05-23

Abstract: Hybrid precoding design is challenging for millimeter-wave (mmWave) massive MIMO. Most prior hybrid precoding schemes are designed to maximize the sum spectral efficiency (SSE), while seldom investigate the bit-error-rate (BER). Therefore, this letter designs an over-sampling codebook (OSC)-based hybrid minimum sum-mean-square-error (min-SMSE) precoding to optimize the BER. Specifically, given the effective baseband channel consisting of the real channel and analog precoding, we first design the digital precoder/combiner based on min-SMSE criterion to optimize the BER. To further reduce the SMSE between the transmit and receive signals, we propose an OSC-based joint analog precoder/combiner (JAPC) design. Simulation results show that the proposed scheme can achieve the better performance than its conventional counterparts.
Over-Sampling Codebook-Based Hybrid Minimum Sum-Mean-Square-Error Precoding for Millimeter-Wave 3D-MIMO

KAUST Repository

Mao, Jiening; Gao, Zhen; Wu, Yongpeng; Alouini, Mohamed-Slim

2018-01-01

Hybrid precoding design is challenging for millimeter-wave (mmWave) massive MIMO. Most prior hybrid precoding schemes are designed to maximize the sum spectral efficiency (SSE), while seldom investigate the bit-error-rate (BER). Therefore, this letter designs an over-sampling codebook (OSC)-based hybrid minimum sum-mean-square-error (min-SMSE) precoding to optimize the BER. Specifically, given the effective baseband channel consisting of the real channel and analog precoding, we first design the digital precoder/combiner based on min-SMSE criterion to optimize the BER. To further reduce the SMSE between the transmit and receive signals, we propose an OSC-based joint analog precoder/combiner (JAPC) design. Simulation results show that the proposed scheme can achieve the better performance than its conventional counterparts.
The benefits of Square dancing as a means of physical activity for Czech dancers with hearing loss

Directory of Open Access Journals (Sweden)

Petra Kurková

2014-12-01

Full Text Available Background: Hearing, a strong line of communication that enables individuals to learn about the world around them, is a major factor contributing to the psychomotor development of every individual. Hearing loss can also affect the conception and perception of sounds and rhythm. Objective: The purpose of this study was to describe and analyse the benefits of Square and Round dancing for persons with hearing loss. Methods: The present study is an analytic-descriptive qualitative research. The sample was constituted non-probabilistically based on the following features: a a participant had to have hearing problems (hearing loss and b had to have participated regularly in Square dance for at least two years. Each participant was asked to name possible people to be interviewed (snowball technique. We analysed the data of 7 individuals (6 males and 1 female with hearing loss. The mean age of the dancers with hearing loss was 51.3 years. The participants had no cochlear implants or any other physical or vision related impairments. Results: The present findings constitute the first published survey regarding Czech Square dancers' status, their family's hearing status, hearing aid use, communication preference, education in integrated or segregated settings, the influence of family background on dance initiation, coach preference (hearing or deaf, and the environment for participation in Square dance as a mode of physical activity with regular dancers and with dancers with hearing loss as well. In the present sample of dancers with hearing loss, most were from hearing families and had hearing siblings. The degree to which individuals with hearing loss feel comfortable with the hearing world appears to influence their later preference for participating in regular, as opposed to segregated, physical activities. More than half of the dancers with hearing loss who participated in this research study would like to meet with the deaf minority. One of the
The conditions for total reflection of low-energy atoms from crystal surfaces

International Nuclear Information System (INIS)

Hou, M.; Robinson, M.T.

1978-01-01

The critical angles for the total reflection of low-energy particles from Cu rows and (001) planes have been investigated, using the binary collision approximation computer simulation code MARLOWE Breakthrough angles were evaluated for H, N, Ne, Ar, Cu, Xe, and Au in the energy range from 0.1 to 7.5 keV. In both the axial and the planar cases, recoiling of the target atoms lowers the energy barrier which the target surface presents to the heavy projectiles. Consequently, the breakthrough angles are reduced for heavy projectiles below the values expected either from observations on light projectiles or from analytical channeling theory. (orig.) [de
A Trajectory Regression Clustering Technique Combining a Novel Fuzzy C-Means Clustering Algorithm with the Least Squares Method

Directory of Open Access Journals (Sweden)

Xiangbing Zhou

2018-04-01

Full Text Available Rapidly growing GPS (Global Positioning System trajectories hide much valuable information, such as city road planning, urban travel demand, and population migration. In order to mine the hidden information and to capture better clustering results, a trajectory regression clustering method (an unsupervised trajectory clustering method is proposed to reduce local information loss of the trajectory and to avoid getting stuck in the local optimum. Using this method, we first define our new concept of trajectory clustering and construct a novel partitioning (angle-based partitioning method of line segments; second, the Lagrange-based method and Hausdorff-based K-means++ are integrated in fuzzy C-means (FCM clustering, which are used to maintain the stability and the robustness of the clustering process; finally, least squares regression model is employed to achieve regression clustering of the trajectory. In our experiment, the performance and effectiveness of our method is validated against real-world taxi GPS data. When comparing our clustering algorithm with the partition-based clustering algorithms (K-means, K-median, and FCM, our experimental results demonstrate that the presented method is more effective and generates a more reasonable trajectory.
Efficient Means of Detecting Neutral Atoms in Space

Science.gov (United States)

Zinicola, W. N.

2006-12-01

This summer, The Society of Physics Students granted me the opportunity to participate in an internship for The National Aeronautics and Space Administration (NASA) and The University of Maryland. Our chief interest was analyzing low energy neutral atoms that were created from random interactions of ions in space plasma. From detecting these neutrals one can project a image of what the plasma's composition is, and how this plasma changes through interactions with the solar wind. Presently, low energy neutral atom detectors have poor efficiency, typically in the range of 1%. Our goal was to increase this efficiency. To detect low energy neutrals we must first convert them from neutral molecules to negatively charged ions. Once converted, these "new" negatively charged ions can be easily detected and completely analyzed giving us information about their energy, mass, and instantaneous direction. The efficiency of the detector is drastically affected by the surface used for converting these neutrals. My job was first to create thin metal conversion surfaces. Then, using an X-ray photoelectron spectrometer, analyze atomic surface composition and gather work function values. Once the work function values were known we placed the surfaces in our neutral detector and measured their conversion efficiencies. Finally, a relation between the work function of the metal surface an its conversion efficiency was generated. With this relationship accurately measured one could use this information to help give suggestions on what surface would be the best to increase our detection efficiency. If we could increase the efficiency of these low energy neutral atom detectors by even 1% we would be able to decrease the size of the detector therefore making it cheaper and more applicable for space exploration.* * A special thanks to Dr. Michael Coplan of the University of Maryland for his support and guidance through all my research.
Anti-Adhesion Elastomer Seal Coatings for Ultraviolet and Atomic Oxygen Protection

Science.gov (United States)

De Groh, Henry C., III; Puleo, Bernadette J.; Waters, Deborah L.; Miller, Sharon K.

2015-01-01

Radiation blocking sunscreen coatings have been developed for the protection of elastomer seals used in low-Earth-orbit (LEO). The coatings protect the seals from ultraviolet (UV) radiation and atomic oxygen (AO) damage. The coatings were developed for use on NASA docking seals. Docking seal damage from the UV and AO present in LEO can constrain mission time-line, flight mode options, and increases risk. A low level of adhesion is also required for docking seals so undocking push-off forces can be low. The coatings presented also mitigate this unwanted adhesion. Greases with low collected volatile condensable materials (CVCM) and low total mass loss (TML) were mixed with slippery and/or UV blocking powders to create the protective coatings. Coatings were applied at rates up to 2 milligrams per square centimeter. Coated seals were exposed to AO and UV in the NUV (near-UV) and UV-C wavelength ranges (300 to 400 nanometers and 254 nanometers, respectively). Ground based ashers were used to simulate the AO of space. The Sun's UV energy was mimicked assuming a nose forward flight mode, resulting in an exposure rate of 2.5 megajoules per square meter per day. Exposures between 0 and 147 megajoules per square meter (UV-C) and 245 megajoules per square meter (NUV) were accomplished. The protective coatings were durable, providing protection from UV after a simulated docking and undocking cycle. The level of protection begins to decline at coverage rates less than 0.9 milligrams per square centimeter. The leakage of seals coated with Braycote plus 20 percent Z-cote ZnO sunscreen increased by a factor of 40 after moderate AO exposure; indicating that this coating might not be suitable due to AO intolerance. Seals coated with DC-7-16.4 percent Z-cote ZnO sunscreen were not significantly affected by combined doses of 2 x 10 (sup 21) atoms per square AO with 73 megajoules per square meter UV-C. Unprotected seals were significantly damaged at UV-C exposures of 0.3 megajoules per
Spontaneous Formation of A Nanotube From A Square Ag Nanowire: An Atomistic View

Science.gov (United States)

Konuk Onat, Mine; Durukanoglu, Sondan

2012-02-01

We have performed molecular static calculations to investigate the recently observed phenomenon of the spontaneous formation of a nanotube from a regular, square Ag nanowire[1]. In the simulations, atoms are allowed to interact via the model potential obtained from the modified embedded atom method. Our simulations predict that this particular type of structural phase transformation is controlled by the nature of applied strain, length of the wire and initial cross-sectional shape. For such a perfect structural transformation, the axially oriented fcc nanowire needs (1) to be formed by stacking A and B layers of an fcc crystal, both possessing the geometry of two interpenetrating one-lattice-parameter-wide squares, containing four atoms each, (2) to have an optimum length of eight layers, and (3) to be exposed to a combination of low and high stress along the length direction. The results further offer insights into atomistic nature of this specific structural transformation into a nanotube with the smallest possible cross-section. [1] M.J. Lagos et al., Nature Nanotech. 4, 149 (2009).
Theoretical experimental study of the factors that govern the molybdenum absorption signal by means of electro thermic atomic absorption spectroscopy

International Nuclear Information System (INIS)

Garaboto Farfan, M. A.

1996-01-01

The formation of molybdenum carbides in the atomizer, used in the electro thermic atomic absorption spectroscopy, is responsible for incomplete analyte removal in its analysis. This generates the apparition of the memory effect and little precision in the results. In this work, different variables that could affect the molybdenum absorption sign were investigated, as well as the influence of hydrochloric acid on the memory effect, by means of studies in the different stages: drying, calcination and atomization, and the samples deposition order in molybdenum solutions, either acidified or not acidified [es
Labelling of macromoleculear carbohydrates by means of 'Hot Atom' reactions

International Nuclear Information System (INIS)

Lundqvist, H.; Malmborg, P.

1976-01-01

Radioactive labelling of polysaccharides have been performed using atoms with such high kinetic energy that they can break normally very stable bindings thus permitting labelling by substitution reactions. Such atoms can be produced in nuclear transformations. We have chosen to study the labelling efficiency of 'hot atoms' ( 77 Br, 123 I and 125 I) produced in radioactive decay (β + -decay and E.C.) of noble gas nuclides ( 77 Kr, 123 Xe and 125 Xe) which easily could be brought in close contact with the molecule to be labelled. Substances to be labelled have been starch particles and high molecular weight glycogen. (author)
Atomic- and void-species nanostructures in chalcogenide glasses modified by high-energy γ-irradiation

International Nuclear Information System (INIS)

Kavetskyy, T.; Shpotyuk, O.; Kaban, I.; Hoyer, W.

2007-01-01

Atomic- and void-species nanostructures are studied in As 2 S 3 glass in unmodified and γ-modified states using a combination of conventional X-ray diffraction with respect to the first sharp diffraction peak, synchrotron-based high-energy X-ray diffraction and extended X-ray absorption fine structure spectroscopy. The experimental data are analyzed taking into account radiation-induced changes in the parameters of the first sharp diffraction peak (position, full width at half maximum, intensity), packing factor, structural disordering, atomic and void topology, coordination number and mean square deviation in bond length. The origin of the structural modification effect induced by γ-irradiation is explained in terms of coordination topological defects model. (authors)

Incoherent dictionary learning for reducing crosstalk noise in least-squares reverse time migration

Science.gov (United States)

Wu, Juan; Bai, Min

2018-05-01

We propose to apply a novel incoherent dictionary learning (IDL) algorithm for regularizing the least-squares inversion in seismic imaging. The IDL is proposed to overcome the drawback of traditional dictionary learning algorithm in losing partial texture information. Firstly, the noisy image is divided into overlapped image patches, and some random patches are extracted for dictionary learning. Then, we apply the IDL technology to minimize the coherency between atoms during dictionary learning. Finally, the sparse representation problem is solved by a sparse coding algorithm, and image is restored by those sparse coefficients. By reducing the correlation among atoms, it is possible to preserve most of the small-scale features in the image while removing much of the long-wavelength noise. The application of the IDL method to regularization of seismic images from least-squares reverse time migration shows successful performance.
Optimal design of minimum mean-square error noise reduction algorithms using the simulated annealing technique.

Science.gov (United States)

Bai, Mingsian R; Hsieh, Ping-Ju; Hur, Kur-Nan

2009-02-01

The performance of the minimum mean-square error noise reduction (MMSE-NR) algorithm in conjunction with time-recursive averaging (TRA) for noise estimation is found to be very sensitive to the choice of two recursion parameters. To address this problem in a more systematic manner, this paper proposes an optimization method to efficiently search the optimal parameters of the MMSE-TRA-NR algorithms. The objective function is based on a regression model, whereas the optimization process is carried out with the simulated annealing algorithm that is well suited for problems with many local optima. Another NR algorithm proposed in the paper employs linear prediction coding as a preprocessor for extracting the correlated portion of human speech. Objective and subjective tests were undertaken to compare the optimized MMSE-TRA-NR algorithm with several conventional NR algorithms. The results of subjective tests were processed by using analysis of variance to justify the statistic significance. A post hoc test, Tukey's Honestly Significant Difference, was conducted to further assess the pairwise difference between the NR algorithms.
Creating Magic Squares.

Science.gov (United States)

Lyon, Betty Clayton

1990-01-01

One method of making magic squares using a prolongated square is illustrated. Discussed are third-order magic squares, fractional magic squares, fifth-order magic squares, decimal magic squares, and even magic squares. (CW)
Variable forgetting factor mechanisms for diffusion recursive least squares algorithm in sensor networks

Science.gov (United States)

Zhang, Ling; Cai, Yunlong; Li, Chunguang; de Lamare, Rodrigo C.

2017-12-01

In this work, we present low-complexity variable forgetting factor (VFF) techniques for diffusion recursive least squares (DRLS) algorithms. Particularly, we propose low-complexity VFF-DRLS algorithms for distributed parameter and spectrum estimation in sensor networks. For the proposed algorithms, they can adjust the forgetting factor automatically according to the posteriori error signal. We develop detailed analyses in terms of mean and mean square performance for the proposed algorithms and derive mathematical expressions for the mean square deviation (MSD) and the excess mean square error (EMSE). The simulation results show that the proposed low-complexity VFF-DRLS algorithms achieve superior performance to the existing DRLS algorithm with fixed forgetting factor when applied to scenarios of distributed parameter and spectrum estimation. Besides, the simulation results also demonstrate a good match for our proposed analytical expressions.
Guidelines for the fitting of anomalous diffusion mean square displacement graphs from single particle tracking experiments.

Directory of Open Access Journals (Sweden)

Eldad Kepten

Full Text Available Single particle tracking is an essential tool in the study of complex systems and biophysics and it is commonly analyzed by the time-averaged mean square displacement (MSD of the diffusive trajectories. However, past work has shown that MSDs are susceptible to significant errors and biases, preventing the comparison and assessment of experimental studies. Here, we attempt to extract practical guidelines for the estimation of anomalous time averaged MSDs through the simulation of multiple scenarios with fractional Brownian motion as a representative of a large class of fractional ergodic processes. We extract the precision and accuracy of the fitted MSD for various anomalous exponents and measurement errors with respect to measurement length and maximum time lags. Based on the calculated precision maps, we present guidelines to improve accuracy in single particle studies. Importantly, we find that in some experimental conditions, the time averaged MSD should not be used as an estimator.
Estimated H-atom anisotropic displacement parameters: a comparison between different methods and with neutron diffraction results

DEFF Research Database (Denmark)

Munshi, Parthapratim; Madsen, Anders Ø; Spackman, Mark A

2008-01-01

systems and identify systematic discrepancies for several atom types. A revised and extended library of internal H-atom mean-square displacements is presented for use with Madsen's SHADE web server [J. Appl. Cryst. (2006), 39, 757-758; http://shade.ki.ku.dk], and the improvement over the original SHADE...... in the agreement with neutron results. The SHADE2 library, now incorporated in the SHADE web server, is recommended as a routine procedure for deriving estimates of H-atom ADPs suitable for use in charge-density studies on molecular crystals, and its widespread use should reveal remaining deficiencies and perhaps...... results is substantial, suggesting that this is now the most readily and widely applicable of the three approximate procedures. Using this new library--SHADE2--it is shown that, in line with expectations, a segmented rigid-body description of the heavy atoms yields only a small improvement...
Using Squares to Sum Squares

Science.gov (United States)

DeTemple, Duane

2010-01-01

Purely combinatorial proofs are given for the sum of squares formula, 1[superscript 2] + 2[superscript 2] + ... + n[superscript 2] = n(n + 1) (2n + 1) / 6, and the sum of sums of squares formula, 1[superscript 2] + (1[superscript 2] + 2[superscript 2]) + ... + (1[superscript 2] + 2[superscript 2] + ... + n[superscript 2]) = n(n + 1)[superscript 2]…
Post-Cam Design and Contact Stress on Tibial Posts in Posterior-Stabilized Total Knee Prostheses: Comparison Between a Rounded and a Squared Design.

Science.gov (United States)

Watanabe, Toshifumi; Koga, Hideyuki; Horie, Masafumi; Katagiri, Hiroki; Sekiya, Ichiro; Muneta, Takeshi

2017-12-01

The post-cam mechanism in posterior stabilized (PS) prostheses plays an important role in total knee arthroplasty (TKA). The purpose of this study is to clarify the difference of the contact stress on the tibial post between a rounded post-cam design and a squared design during deep knee flexion and at hyperextension using the three-dimensional (3D) finite element models. We created 2 types of 3D, finite element models of PS prostheses (types A and B), whose surfaces were identical except for the post-cam geometries: type A has a rounded post-cam design, while type B has a squared design. Both types have a similar curved-shape intercondylar notch of the femoral component. Stress distributions, peak contact stresses, and contact areas on the tibial posts at 90°, 120°, and 150° flexion with/without 10° tibial internal rotation and at 10° hyperextension were compared between the 2 models. Type B demonstrated more concentrated stress distribution compared to type A. The peak contact stresses were similar in both groups during neutral flexion; however, the stresses were much higher in type B during flexion with 10° rotation and at hyperextension. The higher peak contact stresses corresponded to the smaller contact areas in the tibial post. A rounded post-cam design demonstrated less stress concentration during flexion with rotation and at hyperextension compared with a squared design. The results would be useful for development of implant designs and prediction of the contact stress on the tibial post in PS total knee arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.
Atomically flat superconducting nanofilms: multiband properties and mean-field theory

Science.gov (United States)

Shanenko, A. A.; Aguiar, J. Albino; Vagov, A.; Croitoru, M. D.; Milošević, M. V.

2015-05-01

Recent progress in materials synthesis enabled fabrication of superconducting atomically flat single-crystalline metallic nanofilms with thicknesses down to a few monolayers. Interest in such nano-thin systems is attracted by the dimensional 3D-2D crossover in their coherent properties which occurs with decreasing the film thickness. The first fundamental aspect of this crossover is dictated by the Mermin-Wagner-Hohenberg theorem and concerns frustration of the long-range order due to superconductive fluctuations and the possibility to track its impact with an unprecedented level of control. The second important aspect is related to the Fabri-Pérot modes of the electronic motion strongly bound in the direction perpendicular to the nanofilm. The formation of such modes results in a pronounced multiband structure that changes with the nanofilm thickness and affects both the mean-field behavior and superconductive fluctuations. Though the subject is very rich in physics, it is scarcely investigated to date. The main obstacle is that there are no manageable models to study a complex magnetic response in this case. Full microscopic consideration is rather time consuming, if practicable at all, while the standard Ginzburg-Landau theory is not applicable. In the present work we review the main achievements in the subject to date, and construct and justify an efficient multiband mean-field formalism which allows for numerical and even analytical treatment of nano-thin superconductors in applied magnetic fields.
Atomically flat superconducting nanofilms: multiband properties and mean-field theory

International Nuclear Information System (INIS)

Shanenko, A A; Aguiar, J Albino; Vagov, A; Croitoru, M D; Milošević, M V

2015-01-01

Recent progress in materials synthesis enabled fabrication of superconducting atomically flat single-crystalline metallic nanofilms with thicknesses down to a few monolayers. Interest in such nano-thin systems is attracted by the dimensional 3D–2D crossover in their coherent properties which occurs with decreasing the film thickness. The first fundamental aspect of this crossover is dictated by the Mermin–Wagner–Hohenberg theorem and concerns frustration of the long-range order due to superconductive fluctuations and the possibility to track its impact with an unprecedented level of control. The second important aspect is related to the Fabri–Pérot modes of the electronic motion strongly bound in the direction perpendicular to the nanofilm. The formation of such modes results in a pronounced multiband structure that changes with the nanofilm thickness and affects both the mean-field behavior and superconductive fluctuations. Though the subject is very rich in physics, it is scarcely investigated to date. The main obstacle is that there are no manageable models to study a complex magnetic response in this case. Full microscopic consideration is rather time consuming, if practicable at all, while the standard Ginzburg–Landau theory is not applicable. In the present work we review the main achievements in the subject to date, and construct and justify an efficient multiband mean-field formalism which allows for numerical and even analytical treatment of nano-thin superconductors in applied magnetic fields. (paper)
Ab initio calculation atomics ground state wave function for interactions Ion- Atom

International Nuclear Information System (INIS)

Shojaee, F.; Bolori zadeh, M. A.

2007-01-01

Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.
A new stabilized least-squares imaging condition

International Nuclear Information System (INIS)

Vivas, Flor A; Pestana, Reynam C; Ursin, Bjørn

2009-01-01

The classical deconvolution imaging condition consists of dividing the upgoing wave field by the downgoing wave field and summing over all frequencies and sources. The least-squares imaging condition consists of summing the cross-correlation of the upgoing and downgoing wave fields over all frequencies and sources, and dividing the result by the total energy of the downgoing wave field. This procedure is more stable than using the classical imaging condition, but it still requires stabilization in zones where the energy of the downgoing wave field is small. To stabilize the least-squares imaging condition, the energy of the downgoing wave field is replaced by its average value computed in a horizontal plane in poorly illuminated regions. Applications to the Marmousi and Sigsbee2A data sets show that the stabilized least-squares imaging condition produces better images than the least-squares and cross-correlation imaging conditions
Mean total arsenic concentrations in chicken 1989-2000 and estimated exposures for consumers of chicken.

OpenAIRE

Lasky, Tamar; Sun, Wenyu; Kadry, Abdel; Hoffman, Michael K

2004-01-01

The purpose of this study was to estimate mean concentrations of total arsenic in chicken liver tissue and then estimate total and inorganic arsenic ingested by humans through chicken consumption. We used national monitoring data from the Food Safety and Inspection Service National Residue Program to estimate mean arsenic concentrations for 1994-2000. Incorporating assumptions about the concentrations of arsenic in liver and muscle tissues as well as the proportions of inorganic and organic a...
Total and Local Quadratic Indices of the Molecular Pseudograph's Atom Adjacency Matrix: Applications to the Prediction of Physical Properties of Organic Compounds

Directory of Open Access Journals (Sweden)

Yovani Marrero Ponce

2003-08-01

Full Text Available A novel topological approach for obtaining a family of new molecular descriptors is proposed. In this connection, a vector space E (molecular vector space, whose elements are organic molecules, is defined as a Ã¢Â€Âœdirect sumÃ¢Â€Âœ of different Ã¢Â„Âœi spaces. In this way we can represent molecules having a total of i atoms as elements (vectors of the vector spaces Ã¢Â„Âœi (i=1, 2, 3,..., n; where n is number of atoms in the molecule. In these spaces the components of the vectors are atomic properties that characterize each kind of atom in particular. The total quadratic indices are based on the calculation of mathematical quadratic forms. These forms are functions of the k-th power of the molecular pseudograph's atom adjacency matrix (M. For simplicity, canonical bases are selected as the quadratic forms' bases. These indices were generalized to Ã¢Â€Âœhigher analoguesÃ¢Â€Âœ as number sequences. In addition, this paper also introduces a local approach (local invariant for molecular quadratic indices. This approach is based mainly on the use of a local matrix [Mk(G, FR]. This local matrix is obtained from the k-th power (Mk(G of the atom adjacency matrix M. Mk(G, FR includes the elements of the fragment of interest and those that are connected with it, through paths of length k. Finally, total (and local quadratic indices have been used in QSPR studies of four series of organic compounds. The quantitative models found are significant from a statistical point of view and permit a clear interpretation of the studied properties in terms of the structural features of molecules. External prediction series and cross-validation procedures (leave-one-out and leave-group-out assessed model predictability. The reported method has shown similar results, compared with other topological approaches. The results obtained were the following: a Seven physical properties of 74 normal and branched alkanes (boiling points
Analytical formulae for total cross sections for electron scattering by atoms (N, O, F, Ne, P, S, Cl, Ar, As, Se, Br, Kr) between 0.5-10 keV

International Nuclear Information System (INIS)

Williart, A.

2001-01-01

Analytical formulae for total cross sections for electron scattering by atoms which are close to the noble gases (Ne, Ar and Kr), for electron energies ranging from 0.5 to 10 keV, have been obtained in this study. We have shown, previously, that molecular total cross sections, at these energies, depend on target polarizability and the number of target electrons. A similar behaviour has been supposed for total cross sections of some atoms (N, O, F, P, S, Cl, As, Se and Br). The obtained expression depends on atomic parameters and it is based in some correlation derived from noble gases. The applicability of the formula has been checked by comparison with available data for atomic oxygen. (orig.)
Analytical formulae for total cross sections for electron scattering by atoms (N, O, F, Ne, P, S, Cl, Ar, As, Se, Br, Kr) between 0.5-10 keV

Energy Technology Data Exchange (ETDEWEB)

Williart, A. [Univ. Nacional de Educacion a Distancia, Madrid (Spain). Dept. de Fisica de los Materiales; Garcia, G. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)

2001-10-01

Analytical formulae for total cross sections for electron scattering by atoms which are close to the noble gases (Ne, Ar and Kr), for electron energies ranging from 0.5 to 10 keV, have been obtained in this study. We have shown, previously, that molecular total cross sections, at these energies, depend on target polarizability and the number of target electrons. A similar behaviour has been supposed for total cross sections of some atoms (N, O, F, P, S, Cl, As, Se and Br). The obtained expression depends on atomic parameters and it is based in some correlation derived from noble gases. The applicability of the formula has been checked by comparison with available data for atomic oxygen. (orig.)
Quality Control of Valerianae Radix by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy.

Science.gov (United States)

Nikzad-Langerodi, Ramin; Arth, Katharina; Klatte-Asselmeyer, Valerie; Bressler, Sabine; Saukel, Johannes; Reznicek, Gottfried; Dobeš, Christoph

2018-04-01

(Acetoxy-)valerenic acid and total essential oil content are important quality attributes of pharmacy grade valerian root (Valerianae radix). Traditional analysis of these quantities is time-consuming and necessitates (harmful) solvents. Here we investigated an application of attenuated total reflection Fourier transform infrared spectroscopy for extractionless analysis of these quality attributes on a representative sample comprising 260 wild-crafted individuals covering the Central European taxonomic diversity of the Valeriana officinalis L. s. l. species aggregate with its three major ploidy cytotypes (i.e., di-, tetra- and octoploid). Calibration models were built by orthogonal partial least squares regression for quantitative analysis of (acetoxy-)valerenic acid and total essential oil content. For the latter, we propose a simplistic protocol involving apolar extraction followed by gas chromatography as a reference method for multivariate calibration in order to handle the analysis of samples taken from individual plants. We found good predictive ability of chemometric models for quantification of valerenic acid, acetoxyvalerenic acid, total sesquiterpenoid acid, and essential oil content with a root mean squared error of cross-validation of 0.064, 0.043, and 0.09 and root mean squared error of prediction of 0.066, 0.057, and 0.09 (% content), respectively. Orthogonal partial least squares discriminant analysis revealed good discriminability between the most productive phenotype (i.e., the octoploid cytotype) in terms of sesquiterpenoid acids, and the less productive ones (i.e., di- and tetraploid). All in all, our results demonstrate the application of attenuated total reflection Fourier transform infrared spectroscopy for rapid, extractionless estimation of the most important quality attributes of valerian root and minimally invasive identification of the most productive phenotype in terms of sesquiterpenoid acids. Georg Thieme Verlag KG Stuttgart · New
Electron and positron atomic elastic scattering cross sections

International Nuclear Information System (INIS)

Stepanek, Jiri

2003-01-01

A method was developed to calculate the total and differential elastic-scattering cross sections for incident electrons and positrons in the energy range from 0.01 eV to 1 MeV for atoms of Z=1-100. For electrons, hydrogen, helium, nitrogen, oxygen, krypton, and xenon, and for positrons, helium, neon, and argon atoms were considered for comparison with experimental data. First, the variationally optimized atomic static potentials were calculated for each atom by solving the Dirac equations for bound electron states. Second, the Dirac equations for a free electron or positron are solved for an atom using the previously calculated static potential accomplished (in the case of electrons) by 'adjusted' Hara's exchange potential for a free-state particle. Additional to the exchange effects, the charge cloud polarization effects are considered applying the correlation-polarization potential of O'Connell and Lane (with correction of Padial and Norcross) for incident electrons, and of Jain for incident positrons. The total, cutoff and differential elastic-scattering cross sections are calculated for incident electrons and positrons with the help of the relativistic partial wave analysis. The solid state effects for scattering in solids are described by means of a muffin-tin model, i.e. the potentials of neighboring atoms are superpositioned in such a way that the resulting potential and its derivative are zero in the middle distance between the atoms. The potential of isolated atom is calculated up to the radius at which the long-range polarization potential becomes a value of -10 -8
High radiofrequency radiation at Stockholm Old Town: An exposimeter study including the Royal Castle, Supreme Court, three major squares and the Swedish Parliament

Science.gov (United States)

Hardell, Lennart; Carlberg, Michael; Koppel, Tarmo; Hedendahl, Lena

2017-01-01

Exposure to radiofrequency (RF) radiation was classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer at WHO in 2011. The exposure pattern is changing due to the rapid development of technology. Outdoor RF radiation level was measured during five tours in Stockholm Old Town in April, 2016 using the EME Spy 200 exposimeter with 20 predefined frequencies. The results were based on 10,437 samples in total. The mean level of the total RF radiation was 4,293 µW/m2 (0.4293 µW/cm2). The highest mean levels were obtained for global system for mobile communications (GSM) + universal mobile telecommunications system (UMTS) 900 downlink and long-term evolution (LTE) 2600 downlink (1,558 and 1,265 µW/m2, respectively). The town squares displayed highest total mean levels, with the example of Järntorget square with 24,277 µW/m2 (min 257, max 173,302 µW/m2). These results were in large contrast to areas with lowest total exposure, such as the Supreme Court, with a mean level of 404 µW/m2 (min 20.4, max 4,088 µW/m2). In addition, measurements in the streets surrounding the Royal Castle were lower than the total for the Old Town, with a mean of 756 µW/m2 (min 0.3, max 50,967 µW/m2). The BioInitiative 2012 Report defined the scientific benchmark for possible health risks as 30–60 µW/m2. Our results of outdoor RF radiation exposure at Stockholm Old Town are significantly above that level. The mean exposure level at Järntorget square was 405-fold higher than 60 µW/m2. Our results were below the reference level on 10,000,000 µW/m2 established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), which, however, are less credible, as they do not take non-thermal effects into consideration and are not based on sound scientific evaluation. Our highest measured mean level at Järntorget was 0.24% of the ICNIRP level. A number of studies have found adverse, non-thermal (no measurable temperature
High radiofrequency radiation at Stockholm Old Town: An exposimeter study including the Royal Castle, Supreme Court, three major squares and the Swedish Parliament.

Science.gov (United States)

Hardell, Lennart; Carlberg, Michael; Koppel, Tarmo; Hedendahl, Lena

2017-04-01

Exposure to radiofrequency (RF) radiation was classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer at WHO in 2011. The exposure pattern is changing due to the rapid development of technology. Outdoor RF radiation level was measured during five tours in Stockholm Old Town in April, 2016 using the EME Spy 200 exposimeter with 20 predefined frequencies. The results were based on 10,437 samples in total. The mean level of the total RF radiation was 4,293 µW/m 2 (0.4293 µW/cm 2 ). The highest mean levels were obtained for global system for mobile communications (GSM) + universal mobile telecommunications system (UMTS) 900 downlink and long-term evolution (LTE) 2600 downlink (1,558 and 1,265 µW/m 2 , respectively). The town squares displayed highest total mean levels, with the example of Järntorget square with 24,277 µW/m 2 (min 257, max 173,302 µW/m 2 ). These results were in large contrast to areas with lowest total exposure, such as the Supreme Court, with a mean level of 404 µW/m 2 (min 20.4, max 4,088 µW/m 2 ). In addition, measurements in the streets surrounding the Royal Castle were lower than the total for the Old Town, with a mean of 756 µW/m 2 (min 0.3, max 50,967 µW/m 2 ). The BioInitiative 2012 Report defined the scientific benchmark for possible health risks as 30-60 µW/m 2 . Our results of outdoor RF radiation exposure at Stockholm Old Town are significantly above that level. The mean exposure level at Järntorget square was 405-fold higher than 60 µW/m 2 . Our results were below the reference level on 10,000,000 µW/m 2 established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), which, however, are less credible, as they do not take non-thermal effects into consideration and are not based on sound scientific evaluation. Our highest measured mean level at Järntorget was 0.24% of the ICNIRP level. A number of studies have found adverse, non-thermal (no measurable

Precise determination of total absorption coefficients for low-energy gamma-quanta with Moessbauer effect

International Nuclear Information System (INIS)

Bonchev, T.; Statev, S.; Nejkov, Kh.

1980-01-01

A new method of determining the total absorption coefficient applying the Moessbauer effect is proposed. This method enables the accuracy of the measurement increase. The coefficient is measured with practically no background on using the recoilless part of gamma radiation obtained from the Moessbauer source with and without the sample between the source of the gamma-quanta and the detector. Moessbauer sources and absorbers with a single line and without an isomeric shift are used. The recoilless part of the radiation is obtained by the ''two point'' method as a difference between the numbers of photons corresponding to the stationary source and to the vibrating one with a big mean square velocity, respectively. In the concrete measurements the sources 57 Co and 119 Sn are used. The total absorption coefficient for different samples beginning with water up to plumbum is determined. The mean square error for the mean result in all measurements is less than the mean statistical error for the coefficient. The obtained experimental data give a much smaller deviation from the theoretical data of the last issue of the Stom-Israel Tables than the one expected by their authors
Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

International Nuclear Information System (INIS)

Rodriguez Roman, S.

1997-01-01

This study developed a method for the cuantitative analysis of arsenic in potable water , through the spectrophotometric technique of atomic absorption. It used an automatic system of injection of flux for the generation of hydrides. It studied the effect produced by reducer agents, in the prereduction of arsenic in water, obtaining the best result with the use of potasium iodide 1.5% and ascorbic acid 0.25% in hydrochloric acid 3.7%, for the direct determination of total inorganic arsenic. It observed the effect produced by cadmium and selenium to the half of the concentration of arsenic, chromium, lead and silver at the same concentration, and barium at a ten times higher concentration, in the recuperation of total inorganic arsenic. It also used sodium borohydride 0.3% in sodium hydroxide 0.05% (5mL/min), for the formation of the volatile hydrides. It used hydrochloric acid 3.7% (12 mL/min) as disolution of transport; argon as inert gas, and a flame air-acetylene, for the atomization of the hydrides. This method was applied to 19 samples of potable water, and the result was no detectable for all of them. (S. Grainger)
Mean multiplicity in the Regge models with rising cross sections

International Nuclear Information System (INIS)

Chikovani, Z.E.; Kobylisky, N.A.; Martynov, E.S.

1979-01-01

Behaviour of the mean multiplicity and the total cross section σsub(t) of hadron-hadron interactions is considered in the framework of the Regge models at high energies. Generating function was plotted for models of dipole and froissaron, and the mean multiplicity and multiplicity moments were calculated. It is shown that approximately ln 2 S (energy square) in the dipole model, which is in good agreement with the experiment. It is also found that in various Regge models approximately σsub(t)lnS
Mean-field results of the multiple-band extended Hubbard model for the square-planar CuO2 lattice

International Nuclear Information System (INIS)

Nimkar, S.; Sarma, D.D.; Krishnamurthy, H.R.; Ramasesha, S.

1993-01-01

We obtain metal-insulator phase diagrams at half-filling for the five-band extended Hubbard model of the square-planar CuO 2 lattice treated within a Hartree-Fock mean-field approximation, allowing for spiral spin-density waves. We indicate the existence of an insulating phase (covalent insulator) characterized by strong covalency effects, not identified in the earlier Zaanen-Sawatzky-Allen phase diagram. While the insulating phase is always antiferromagnetic, we also obtain an antiferromagnetic metallic phase for a certain range of interaction parameters. Performing a nonperturbative calculation of J eff , the in-plane antiferromagnetic interaction is presented as a function of the parameters in the model. We also calculate the band gap and magnetic moments at various sites and discuss critically the contrasting interpretation of the electronic structure of high-T c materials arising from photoemission and neutron-scattering experiments
Maximum likelihood versus likelihood-free quantum system identification in the atom maser

International Nuclear Information System (INIS)

Catana, Catalin; Kypraios, Theodore; Guţă, Mădălin

2014-01-01

We consider the problem of estimating a dynamical parameter of a Markovian quantum open system (the atom maser), by performing continuous time measurements in the system's output (outgoing atoms). Two estimation methods are investigated and compared. Firstly, the maximum likelihood estimator (MLE) takes into account the full measurement data and is asymptotically optimal in terms of its mean square error. Secondly, the ‘likelihood-free’ method of approximate Bayesian computation (ABC) produces an approximation of the posterior distribution for a given set of summary statistics, by sampling trajectories at different parameter values and comparing them with the measurement data via chosen statistics. Building on previous results which showed that atom counts are poor statistics for certain values of the Rabi angle, we apply MLE to the full measurement data and estimate its Fisher information. We then select several correlation statistics such as waiting times, distribution of successive identical detections, and use them as input of the ABC algorithm. The resulting posterior distribution follows closely the data likelihood, showing that the selected statistics capture ‘most’ statistical information about the Rabi angle. (paper)
Quantitative determination of polyphosphate in sediments using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and partial least squares regression.

Science.gov (United States)

Khoshmanesh, Aazam; Cook, Perran L M; Wood, Bayden R

2012-08-21

Phosphorus (P) is a major cause of eutrophication and subsequent loss of water quality in freshwater ecosystems. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. Despite the broad relevance of polyphosphate (Poly-P) in bioremediation and P release processes in the environment, its quantification is not yet well developed for sediment samples. Current methods possess significant disadvantages because of the difficulties associated with using a single extractant to extract a specific P compound without altering others. A fast and reliable method to estimate the quantitative contribution of microorganisms to sediment P release processes is needed, especially when an excessive P accumulation in the form of polyphosphate (Poly-P) occurs. Development of novel approaches for application of emerging spectroscopic techniques to complex environmental matrices such as sediments significantly contributes to the speciation models of P mobilization, biogeochemical nutrient cycling and development of nutrient models. In this study, for the first time Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in combination with partial least squares (PLS) was used to quantify Poly-P in sediments. To reduce the high absorption matrix components in sediments such as silica, a physical extraction method was developed to separate sediment biological materials from abiotic particles. The aim was to achieve optimal separation of the biological materials from sediment abiotic particles with minimum chemical change in the sample matrix prior to ATR-FTIR analysis. Using a calibration set of 60 samples for the PLS prediction models in the Poly-P concentration range of 0-1 mg g(-1) d.w. (dry weight of sediment) (R(2) = 0.984 and root mean square error of prediction RMSEP = 0.041 at Factor-1) Poly-P could be detected at less than 50 μg g(-l) d.w. Using this technique, there is no solvent extraction or chemical
Average and extreme multi-atom Van der Waals interactions: Strong coupling of multi-atom Van der Waals interactions with covalent bonding

Directory of Open Access Journals (Sweden)

Finkelstein Alexei V

2007-07-01

Full Text Available Abstract Background The prediction of ligand binding or protein structure requires very accurate force field potentials – even small errors in force field potentials can make a 'wrong' structure (from the billions possible more stable than the single, 'correct' one. However, despite huge efforts to optimize them, currently-used all-atom force fields are still not able, in a vast majority of cases, even to keep a protein molecule in its native conformation in the course of molecular dynamics simulations or to bring an approximate, homology-based model of protein structure closer to its native conformation. Results A strict analysis shows that a specific coupling of multi-atom Van der Waals interactions with covalent bonding can, in extreme cases, increase (or decrease the interaction energy by about 20–40% at certain angles between the direction of interaction and the covalent bond. It is also shown that on average multi-body effects decrease the total Van der Waals energy in proportion to the square root of the electronic component of dielectric permittivity corresponding to dipole-dipole interactions at small distances, where Van der Waals interactions take place. Conclusion The study shows that currently-ignored multi-atom Van der Waals interactions can, in certain instances, lead to significant energy effects, comparable to those caused by the replacement of atoms (for instance, C by N in conventional pairwise Van der Waals interactions.
Forecasting Error Calculation with Mean Absolute Deviation and Mean Absolute Percentage Error

Science.gov (United States)

Khair, Ummul; Fahmi, Hasanul; Hakim, Sarudin Al; Rahim, Robbi

2017-12-01

Prediction using a forecasting method is one of the most important things for an organization, the selection of appropriate forecasting methods is also important but the percentage error of a method is more important in order for decision makers to adopt the right culture, the use of the Mean Absolute Deviation and Mean Absolute Percentage Error to calculate the percentage of mistakes in the least square method resulted in a percentage of 9.77% and it was decided that the least square method be worked for time series and trend data.
Radiochemical investigations on the decomposition of (mono)methylmercury by means of acid with regard to the determination of total mercury in fish

International Nuclear Information System (INIS)

Harms, U.

1976-01-01

Considerable amounts of mercury in fish muscle tissue are organically bound, i.e. appear as (mono)methylmercury-compounds. In order to make mercury of organic origin available for the determination of total mercury by the 'cold vapour atomic absorption method', a splitting of the carbon-mercury bond by means of suitable chemical treatment must be maintained beforehand. The main subject of this article are investigations with special regard to the behaviour of (mono)methylmercurychloride during different wet digestion methods. The procedures under study involve wet digestion under reflux with HNO 3 , with mixtures of HNO 3 and HClO 4 and HNO 3 and H 2 SO 4 , as well as wet digestion with HNO 3 in a closed system (pressure decomposition). The course of the decomposition of (mono)methylmercury dependent on time, temperature and concentration of reagents are discussed in detail. All experiments were controlled by measurement of the radioactivity of Hg-203 which had been added in the chemical form of CH 3 -Hg-Cl. From the analytical results obtained two methods of sample preparation have been derived that permit a reliable determination of total mercury in fish. (orig.) [de
Estimates of mean consequences and confidence bounds on the mean associated with low-probability seismic events in total system performance assessments

International Nuclear Information System (INIS)

Pensado, Osvaldo; Mancillas, James

2007-01-01

An approach is described to estimate mean consequences and confidence bounds on the mean of seismic events with low probability of breaching components of the engineered barrier system. The approach is aimed at complementing total system performance assessment models used to understand consequences of scenarios leading to radionuclide releases in geologic nuclear waste repository systems. The objective is to develop an efficient approach to estimate mean consequences associated with seismic events of low probability, employing data from a performance assessment model with a modest number of Monte Carlo realizations. The derived equations and formulas were tested with results from a specific performance assessment model. The derived equations appear to be one method to estimate mean consequences without having to use a large number of realizations. (authors)
The Atom-Bond Connectivity Index of Catacondensed Polyomino Graphs

OpenAIRE

Chen, Jinsong; Liu, Jianping; Li, Qiaoliang

2013-01-01

Let G=(V,E) be a graph. The atom-bond connectivity (ABC) index is defined as the sum of weights ((du+dv−2)/dudv)1/2 over all edges uv of G, where du denotes the degree of a vertex u of G. In this paper, we give the atom-bond connectivity index of the zigzag chain polyomino graphs. Meanwhile, we obtain the sharp upper bound on the atom-bond connectivity index of catacondensed polyomino graphs with h squares and determine the corresponding extremal graphs.
Time Scale in Least Square Method

Directory of Open Access Journals (Sweden)

Özgür Yeniay

2014-01-01

Full Text Available Study of dynamic equations in time scale is a new area in mathematics. Time scale tries to build a bridge between real numbers and integers. Two derivatives in time scale have been introduced and called as delta and nabla derivative. Delta derivative concept is defined as forward direction, and nabla derivative concept is defined as backward direction. Within the scope of this study, we consider the method of obtaining parameters of regression equation of integer values through time scale. Therefore, we implemented least squares method according to derivative definition of time scale and obtained coefficients related to the model. Here, there exist two coefficients originating from forward and backward jump operators relevant to the same model, which are different from each other. Occurrence of such a situation is equal to total number of values of vertical deviation between regression equations and observation values of forward and backward jump operators divided by two. We also estimated coefficients for the model using ordinary least squares method. As a result, we made an introduction to least squares method on time scale. We think that time scale theory would be a new vision in least square especially when assumptions of linear regression are violated.
Performance comparison of weighted sum-minimum mean square error and virtual signal-to-interference plus noise ratio algorithms in simulated and measured channels

DEFF Research Database (Denmark)

Rahimi, Maryam; Nielsen, Jesper Ødum; Pedersen, Troels

2014-01-01

A comparison in data achievement between two well-known algorithms with simulated and real measured data is presented. The algorithms maximise the data rate in cooperative base stations (BS) multiple-input-single-output scenario. Weighted sum-minimum mean square error algorithm could be used...... in multiple-input-multiple-output scenarios, but it has lower performance than virtual signal-to-interference plus noise ratio algorithm in theory and practice. A real measurement environment consisting of two BS and two users have been studied to evaluate the simulation results....
Mean excitation energies for molecular ions

Energy Technology Data Exchange (ETDEWEB)

Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: sabin@qtp.ufl.edu [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)

2017-03-01

The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.
Atomic clocks comparison by means of television chain

International Nuclear Information System (INIS)

Silva, J.M.

1974-09-01

The various methods and techniques of time and frequency dissemination are presented. One of them, the Line 10 Method, was used to compare two atomic clocks, localized in different places is a distance of more or less four-hundred kilometers. The results are compared with parallel results obtained with another method, physical transport, giving the necessary experimental basis of the applicability of the Line 10 Method in Brazil [pt
Single crystalline electronic structure and growth mechanism of aligned square graphene sheets

Science.gov (United States)

Yang, H. F.; Chen, C.; Wang, H.; Liu, Z. K.; Zhang, T.; Peng, H.; Schröter, N. B. M.; Ekahana, S. A.; Jiang, J.; Yang, L. X.; Kandyba, V.; Barinov, A.; Chen, C. Y.; Avila, J.; Asensio, M. C.; Peng, H. L.; Liu, Z. F.; Chen, Y. L.

2018-03-01

Recently, commercially available copper foil has become an efficient and inexpensive catalytic substrate for scalable growth of large-area graphene films for fundamental research and applications. Interestingly, despite its hexagonal honeycomb lattice, graphene can be grown into large aligned square-shaped sheets on copper foils. Here, by applying angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES) to study the three-dimensional electronic structures of square graphene sheets grown on copper foils, we verified the high quality of individual square graphene sheets as well as their merged regions (with aligned orientation). Furthermore, by simultaneously measuring the graphene sheets and their substrate copper foil, we not only established the (001) copper surface structure but also discovered that the square graphene sheets' sides align with the ⟨110⟩ copper direction, suggesting an important role of copper substrate in the growth of square graphene sheets—which will help the development of effective methods to synthesize high-quality large-size regularly shaped graphene sheets for future applications. This work also demonstrates the effectiveness of micro-ARPES in exploring low-dimensional materials down to atomic thickness and sub-micron lateral size (e.g., besides graphene, it can also be applied to transition metal dichalcogenides and various van der Waals heterostructures)
Single crystalline electronic structure and growth mechanism of aligned square graphene sheets

Directory of Open Access Journals (Sweden)

H. F. Yang

2018-03-01

Full Text Available Recently, commercially available copper foil has become an efficient and inexpensive catalytic substrate for scalable growth of large-area graphene films for fundamental research and applications. Interestingly, despite its hexagonal honeycomb lattice, graphene can be grown into large aligned square-shaped sheets on copper foils. Here, by applying angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES to study the three-dimensional electronic structures of square graphene sheets grown on copper foils, we verified the high quality of individual square graphene sheets as well as their merged regions (with aligned orientation. Furthermore, by simultaneously measuring the graphene sheets and their substrate copper foil, we not only established the (001 copper surface structure but also discovered that the square graphene sheets’ sides align with the ⟨110⟩ copper direction, suggesting an important role of copper substrate in the growth of square graphene sheets—which will help the development of effective methods to synthesize high-quality large-size regularly shaped graphene sheets for future applications. This work also demonstrates the effectiveness of micro-ARPES in exploring low-dimensional materials down to atomic thickness and sub-micron lateral size (e.g., besides graphene, it can also be applied to transition metal dichalcogenides and various van der Waals heterostructures
Directed Atom-by-Atom Assembly of Dopants in Silicon.

Science.gov (United States)

Hudak, Bethany M; Song, Jiaming; Sims, Hunter; Troparevsky, M Claudia; Humble, Travis S; Pantelides, Sokrates T; Snijders, Paul C; Lupini, Andrew R

2018-05-17

The ability to controllably position single atoms inside materials is key for the ultimate fabrication of devices with functionalities governed by atomic-scale properties. Single bismuth dopant atoms in silicon provide an ideal case study in view of proposals for single-dopant quantum bits. However, bismuth is the least soluble pnictogen in silicon, meaning that the dopant atoms tend to migrate out of position during sample growth. Here, we demonstrate epitaxial growth of thin silicon films doped with bismuth. We use atomic-resolution aberration-corrected imaging to view the as-grown dopant distribution and then to controllably position single dopants inside the film. Atomic-scale quantum-mechanical calculations corroborate the experimental findings. These results indicate that the scanning transmission electron microscope is of particular interest for assembling functional materials atom-by-atom because it offers both real-time monitoring and atom manipulation. We envision electron-beam manipulation of atoms inside materials as an achievable route to controllable assembly of structures of individual dopants.
Metastable argon atom density in complex argon/acetylene plasmas determined by means of optical absorption and emission spectroscopy

International Nuclear Information System (INIS)

Sushkov, Vladimir; Herrendorf, Ann-Pierra; Hippler, Rainer

2016-01-01

Optical emission and absorption spectroscopy has been utilized to investigate the instability of acetylene-containing dusty plasmas induced by growing nano-particles. The density of Ar(1s 5 ) metastable atoms was derived by two methods: tunable diode laser absorption spectroscopy and with the help of the branching ratio method of emitted spectral lines. Results of the two techniques agree well with each other. The density of Ar(1s 3 ) metastable atoms was also measured by means of optical emission spectroscopy. The observed growth instability leads to pronounced temporal variations of the metastable and other excited state densities. An analysis of optical line ratios provides evidence for a depletion of free electrons during the growth cycle but no indication for electron temperature variations. (paper)
Monte Carlo simulation of atomic short range order and cluster formation in two dimensional model alloys

International Nuclear Information System (INIS)

Rojas T, J.; Instituto Peruano de Energia Nuclear, Lima; Manrique C, E.; Torres T, E.

2002-01-01

Using monte Carlo simulation have been carried out an atomistic description of the structure and ordering processes in the system Cu-Au in a two-dimensional model. The ABV model of the alloy is a system of N atoms A and B, located in rigid lattice with some vacant sites. In the model we assume pair wise interactions between nearest neighbors with constant ordering energy J = 0,03 eV. The dynamics was introduced by means of a vacancy that exchanges of place with any atom of its neighbors. The simulations were carried out in a square lattice with 1024 and 4096 particles, using periodic boundary conditions to avoid border effects. We calculate the first two parameters of short range order of Warren-Cowley as function of the concentration and temperature. It was also studied the probabilities of formation of different atomic clusters that consist of 9 atoms as function of the concentration of the alloy and temperatures in a wide range of values. In some regions of temperature and concentration it was observed compositional and thermal polymorphism

Development of an atomic mobility database for liquid phase in multicomponent Al alloys. Focusing on binary systems

Energy Technology Data Exchange (ETDEWEB)

Wang, Shaoqing; Du, Yong; Zhang, Lijun [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Liu, Dandan [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Central South Univ., Changsha, Hunan (China). School of Materials Science and Engineering; Chen, Qing; Engstroem, Anders [Thermo-Calc Software AB, Stockholm (Sweden)

2013-08-15

An atomic mobility database for binary liquid phase in multicomponent Al-Cu-Fe-Mg-Mn-Ni-Si-Zn alloys was established based on critically reviewed experimental and theoretical diffusion data by using DICTRA (Diffusion Controlled TRAnsformation) software. The impurity diffusivities of the elements with limited experimental data are obtained by means of the least-squares method and semi-empirical correlations. Comprehensive comparisons between the calculated and measured diffusivities indicate that most of the reported diffusivities can be well reproduced by the currently obtained atomic mobilities. The reliability of this diffusivity database is further validated by comparing the simulated concentration profiles with the measured ones, as well as the measured main inter-diffusion coefficients of liquid Al-Cu-Zn alloys with the extrapolated ones from the present binary atomic mobility database. The approach is of general validity and applicable to establish mobility databases of other liquid alloys. (orig.)
Experiments with cold hydrogen atoms

International Nuclear Information System (INIS)

Leonas, V.B.

1981-01-01

Numerous investigations of atomic processes in Waseous phase on the surface with participation of ''cold'' hydrogen atoms, made during the last years, are considered. The term ''cold atom'' means the range of relative collision energies E<10 MeV (respectively 'ultracold ' atoms at E< or approximately 1 MeV) which corresponds to the range of temperatures in tens (units) of K degrees. Three main ranges of investigations where extensive experimental programs are realized are considered: study of collisional processes with hydrogen atom participation, hydrogen atoms being of astrophysical interest; study of elastic atom-molecular scattering at superlow energies and studies on the problem of condensed hydrogen. Hydrogen atoms production is realized at dissociation in non-electrode high-frequency or superhigh-frequency discharge. A method of hydrogen quantum generator and of its modifications appeared to be rather an effective means to study collisional changes of spin state of hydrogen atoms. First important results on storage and stabilization of the gas of polarized hydrogen atoms are received
Interplay of vacuum-mediated inter- and intra-atomic couplings in a pair of atoms

International Nuclear Information System (INIS)

Schmid, Sandra Isabelle; Evers, Joerg

2010-01-01

The resonance fluorescence emitted by a system of two dipole-dipole interacting nearby four-level atoms in a J=1/2↔J=1/2 configuration is studied. This setup is the simplest realistic model system which provides a complete description of the (inter-atomic) dipole-dipole interaction for arbitrary orientation of the inter-atomic distance vector, and at the same time allows for intra-atomic spontaneously generated coherences. Our main interest is the interplay of both these different coupling mechanisms. We discuss different methods to analyze the contribution of the various vacuum-induced coupling constants to the total resonance fluorescence spectrum. These allow us to find a dressed state interpretation of the contribution of the different inter-atomic dipole-dipole couplings to the total spectrum. We further study the role of the spontaneously generated coherences, and identify two different contributions to the single-particle vacuum-induced couplings. We show that they have a noticeable impact on the total resonance fluorescence spectrum down to small inter-atomic distances, even though the dipole-dipole coupling constants then are much larger in magnitude than the the single-particle coupling constants. Interestingly, we find that the inter-atomic couplings can induce an effect of the intra-atomic spontaneously generated coherences on the observed spectra which is not present in single-atom systems.
Total mercury of selected fish species from Laguna de Bay

International Nuclear Information System (INIS)

Relon, Milagros Lontoc

1996-01-01

Dalag Ophicephalus striatus Block, kanduli Arius thalassinus Ruppell, bia Amblygobius phalaena Cuvier et Valenciennes and tilapia Tilapia nilotica Linnnaeus collected from Laguna de Bay between Taguig and Binangonan area in August 1989 to July 1990 were analyzed for total mercury by atomic absorption spectrometry. The highest metal concentration in soft muscle tissue was observed in Dalag followed by kanduli, less in bia and least in tilapia with mean values of 0.021, 0.020, 0.013, and 0.008 ug/g, respectively. Analysis using two-way ANOVA showed a significant difference in the mean total mercury in ug/g in the difference fish samples, among the different months and the interaction between these two variables. Mean total mercury of the four fish samples were significantly higher in April than in October. The results show that the levels of total mercury in the fish samples are below the World Health Organization maximum tolerable consumption of mercury in food of 300 ug or 0.03 mg of total mercury per week. (author)
Self-diffusion dynamic behavior of atomic clusters on Re(0 0 0 1) surface

Energy Technology Data Exchange (ETDEWEB)

Liu Fusheng [Department of Applied Physics, Hunan University, Changsha 410082 (China); Hu Wangyu, E-mail: wangyuhu2001cn@yahoo.com.cn [Department of Applied Physics, Hunan University, Changsha 410082 (China); Deng Huiqiu; Luo Wenhua; Xiao Shifang [Department of Applied Physics, Hunan University, Changsha 410082 (China); Yang Jianyu [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China)

2009-08-15

Using molecular dynamics simulations and a modified analytic embedded atom potential, the self-diffusion dynamics of rhenium atomic clusters up to seven atoms on Re(0 0 0 1) surface have been studied in the temperature ranges from 600 K to 1900 K. The simulation time varies from 20 ns to 200 ns according to the cluster sizes and the temperature. The heptamer and trimer are more stable comparing to other neighboring non-compact clusters. The diffusion coefficients of clusters are derived from the mean square displacement of cluster's mass-center, and diffusion prefactors D{sub 0} and activation energies E{sub a} are derived from the Arrhenius relation. It is found that the Arrhenius relation of the adatom can be divided into two parts at different temperature range. The activation energy of clusters increases with the increasing of the atom number in clusters. The prefactor of the heptamer is 2-3 orders of magnitude higher than a usual prefactor because of a large number of nonequivalent diffusion processes. The trimer and heptamer are the nuclei at different temperature range according to the nucleation theory.
[Main Components of Xinjiang Lavender Essential Oil Determined by Partial Least Squares and Near Infrared Spectroscopy].

Science.gov (United States)

Liao, Xiang; Wang, Qing; Fu, Ji-hong; Tang, Jun

2015-09-01

This work was undertaken to establish a quantitative analysis model which can rapid determinate the content of linalool, linalyl acetate of Xinjiang lavender essential oil. Totally 165 lavender essential oil samples were measured by using near infrared absorption spectrum (NIR), after analyzing the near infrared spectral absorption peaks of all samples, lavender essential oil have abundant chemical information and the interference of random noise may be relatively low on the spectral intervals of 7100~4500 cm(-1). Thus, the PLS models was constructed by using this interval for further analysis. 8 abnormal samples were eliminated. Through the clustering method, 157 lavender essential oil samples were divided into 105 calibration set samples and 52 validation set samples. Gas chromatography mass spectrometry (GC-MS) was used as a tool to determine the content of linalool and linalyl acetate in lavender essential oil. Then the matrix was established with the GC-MS raw data of two compounds in combination with the original NIR data. In order to optimize the model, different pretreatment methods were used to preprocess the raw NIR spectral to contrast the spectral filtering effect, after analysizing the quantitative model results of linalool and linalyl acetate, the root mean square error prediction (RMSEP) of orthogonal signal transformation (OSC) was 0.226, 0.558, spectrally, it was the optimum pretreatment method. In addition, forward interval partial least squares (FiPLS) method was used to exclude the wavelength points which has nothing to do with determination composition or present nonlinear correlation, finally 8 spectral intervals totally 160 wavelength points were obtained as the dataset. Combining the data sets which have optimized by OSC-FiPLS with partial least squares (PLS) to establish a rapid quantitative analysis model for determining the content of linalool and linalyl acetate in Xinjiang lavender essential oil, numbers of hidden variables of two
Decomposition of the Mean Squared Error and NSE Performance Criteria: Implications for Improving Hydrological Modelling

Science.gov (United States)

Gupta, Hoshin V.; Kling, Harald; Yilmaz, Koray K.; Martinez-Baquero, Guillermo F.

2009-01-01

The mean squared error (MSE) and the related normalization, the Nash-Sutcliffe efficiency (NSE), are the two criteria most widely used for calibration and evaluation of hydrological models with observed data. Here, we present a diagnostically interesting decomposition of NSE (and hence MSE), which facilitates analysis of the relative importance of its different components in the context of hydrological modelling, and show how model calibration problems can arise due to interactions among these components. The analysis is illustrated by calibrating a simple conceptual precipitation-runoff model to daily data for a number of Austrian basins having a broad range of hydro-meteorological characteristics. Evaluation of the results clearly demonstrates the problems that can be associated with any calibration based on the NSE (or MSE) criterion. While we propose and test an alternative criterion that can help to reduce model calibration problems, the primary purpose of this study is not to present an improved measure of model performance. Instead, we seek to show that there are systematic problems inherent with any optimization based on formulations related to the MSE. The analysis and results have implications to the manner in which we calibrate and evaluate environmental models; we discuss these and suggest possible ways forward that may move us towards an improved and diagnostically meaningful approach to model performance evaluation and identification.
Organic, inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Duarte, Fabio Andrei; Bizzi, Cezar Augusto; Goldschmidt Antes, Fabiane; Dressler, Valderi Luiz; Flores, Erico Marlon de Moraes

2009-01-01

A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L - 1 KBr in 6 mol L - 1 HCl) was added to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L - 1 HCl and 2.5% m/v NaBH 4 solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 deg. C and the atomization temperature was set at 650 deg. C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g - 1 for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.
Determination of total and inorganic mercury in fish samples with on-line oxidation coupled to atomic fluorescence spectrometry

International Nuclear Information System (INIS)

Shao Lijun; Gan Wuer; Su Qingde

2006-01-01

An atomic fluorescence spectrometry system for determination of total and inorganic mercury with electromagnetic induction-assisted heating on-line oxidation has been developed. Potassium peroxodisulphate was used as the oxidizing agent to decompose organomercury compounds. Depending on the temperature selected, inorganic or total mercury could be determined with the same manifold. Special accent was put on the study of the parameters influencing the on-line digestion efficiency. The tolerance to the interference of coexisting ions was carefully examined in this system. Under optimal conditions, the detection limits (3σ) were evaluated to be 2.9 ng l -1 for inorganic mercury and 2.6 ng l -1 for total mercury, respectively. The relative standard deviations for 10 replicate determinations of 1.0 μg l -1 Hg were 2.4 and 3.2% for inorganic mercury and total mercury, respectively. The proposed method was successfully applied to the determination of total and inorganic mercury in fish samples
Application of the backscattering of an atomic beam of thermal energy to the study of the vibrational properties of metal surfaces

International Nuclear Information System (INIS)

Lapujoulade, J.; Lejay, Y.

1975-01-01

Vibrational properties of metal surfaces (surface phonons, surface Debye temperatures) are less known than bulk ones since common investigation methods (neutron, X-rays) are not sensitive to surface properties. A study of the backscattering of an atomic beam may give surface specific informations. The backscattering of noble gas (He, Ne, Ar) from a clean copper single crystal ((100) face) was experimentally studied. The experimental set-up allows to measure the space repartition well as the velocity distribution of the scattered atoms. If the collisions is purely elastic an analysis of the thermal dependence of the specular peak by means of the Debye Waller formula will give the mean square displacements of surface atoms. It is shown however that this simple case is not fulfilled with helium in ordinary beam or solid temperatures. If the collision is inelastic, but dominated by single phonon transfers (as it seems to be the case for helium) information should to get about the phonon dispersion relation of surface atoms. When many-phonon collision occur (Ne and Ar) the analysis is more difficult. A comparison of the experimental result with an approximate calculation of G. Armand is given [fr
Composition of Cu/Al system constructed by means of dynamic atomic deposition

International Nuclear Information System (INIS)

Tashlykov, I.S.; Tul'ev, V.V.

2011-01-01

Rutherford backscattering and RUMP simulation programme have been applied to investigate composition of Cu/Al system prepared using dynamic atomic deposition process when deposition of Cu thin film on Al substrate was assisted with 6 keV Ar + ions irradiation. It is estimated that thin ( ~15 nm) surface layer consists of ~50 at.% Cu, ~10 at.% Ar, ~4 at.% O and the remaining is Al. Dynamic deposition of Cu on Al substrate is accompanied with radiation enhanced diffusion of Cu, O, Ar atoms in substrate and out diffusion of Al atoms in deposited Cu coating. (authors)
Effects of mode profile on tunneling and traversal of ultracold atoms through vacuum-induced potentials

Science.gov (United States)

Badshah, Fazal; Irfan, Muhammad; Qamar, Sajid; Qamar, Shahid

2016-04-01

We consider the resonant interaction of an ultracold two-level atom with an electromagnetic field inside a high-Q micromaser cavity. In particular, we study the tunneling and traversal of ultracold atoms through vacuum-induced potentials for secant hyperbolic square and sinusoidal cavity mode functions. The phase time which may be considered as an appropriate measure of the time required for the atoms to cross the cavity, significantly modifies with the change of cavity mode profile. For example, switching between the sub and superclassical behaviors in phase time can occur due to the mode function. Similarly, negative phase time appears for the transmission of the two-level atoms in both excited and ground states for secant hyperbolic square mode function which is in contrast to the mesa mode case.
Radiation Field of a Square, Helical Beam Antenna

DEFF Research Database (Denmark)

Knudsen, Hans Lottrup

1952-01-01

square helices are used. Further, in connection with corresponding rigorous formulas for the field from a circular, helical antenna with a uniformly progressing current wave of constant amplitude the present formulas may be used for an investigation of the magnitude of the error introduced in Kraus......' approximate calculation of the field from a circular, helical antenna by replacing this antenna with an ``equivalent'' square helix. This investigation is carried out by means of a numerical example. The investigation shows that Kraus' approximate method of calculation yields results in fair agreement...
Development of square and hexagonal lattice analysis capability in WIMS-AECL

International Nuclear Information System (INIS)

Donnelly, J.V.

1990-11-01

WIMS, originally developed by the UKAEA (Winfrith), is a widely used computer code for reactor physics analysis of lattice cells. WIMS-AECL (Atomic Energy of Canada Limited) has been developed from a version of the code received from Winfrith in the early 1970s and is generally used within AECL. The facilities existing in the original version of WIMS were very capable for the analysis of reactor designs normally encountered within AECL at that time, such as CANDU fuel lattices, but had limitations in the analysis of more general reactor geometries, such as square light-reactor assemblies. This paper discusses the development and testing of modifications to the two-dimensional collision-probability calculation module in WIMS-AECL to enable more rigorous analysis of lattice geometries based on square or hexagonal cells
Analysis of nutrition-relevant trace elements in human blood and serum by means of total reflection X-ray fluorescence (TXRF) spectroscopy

International Nuclear Information System (INIS)

Stosnach, Hagen; Mages, Margarete

2009-01-01

In clinical service laboratories, one of the most common analytical tasks with regard to inorganic traces is the determination of the nutrition-relevant elements Fe, Cu, Zn, and Se. Because of the high numbers of samples and the commercial character of these analyses, a time-consuming sample preparation must be avoided. In this presentation, the results of total reflection X-ray fluorescence measurements with a low-power system and different sample preparation procedures are compared with those derived from analysis with common methods like Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The results of these investigations indicate that the optimal total reflection X-ray fluorescence analysis of the nutrition-relevant elements Fe, Cu, Zn, and Se can be performed by preparing whole blood and serum samples after dilution with ultrapure water and transferring 10 μl of internally standardized sample to an unsiliconized quartz glass sample carrier with subsequent drying in a laboratory oven. Suitable measurement time was found to be 600 s. The enhanced sample preparation by means of microwave or open digestion, in parts combined with cold plasma ashing, led to an improvement of detection limits by a factor of 2 for serum samples while for whole blood samples an improvement was only observed for samples prepared by means of microwave digestion. As the matrix elements P, S, Cl, and for whole blood Fe have a major influence on the detection limits, most probably a further enhancement of analytical quality requires the removal of the organic matrix. However, for the routine analysis of the nutrition-relevant elements, the dilution preparation was found to be sufficient.
z calibration of the atomic force microscope by means of a pyramidal tip

DEFF Research Database (Denmark)

Jensen, Flemming

1993-01-01

A new method for imaging the probe tip of an atomic force microscope cantilever by the atomic force microscope itself (self-imaging) is presented. The self-imaging is accomplished by scanning the probe tip across a sharper tip on the surface. By using a pyramidal probe tip with a very well......-defined aspect ratio, this technique provides an excellent z-calibration standard for the atomic force microscope....
Validation of an electrothermal atomization atomic absorption spectrometry method for quantification of total chromium and chromium(VI) in wild mushrooms and underlying soils.

Science.gov (United States)

Figueiredo, Estela; Soares, M Elisa; Baptista, Paula; Castro, Marisa; Bastos, M Lourdes

2007-08-22

An ETAAS method was validated to quantify total Cr and Cr(VI) in mushrooms and the underlying soils. The method includes a sample pretreatment for total Cr dissolution using a wet acid digestion procedure and a selective alkaline extraction for Cr(VI). The limits of detection were, expressed in microg/L, 0.15 and 0.17 for total Cr and Cr(VI), respectively. The linearity ranges under the optimized conditions were 0.15-25.0 and 0.17-20.0 microg/L for total Cr and Cr(VI), respectively. The limits of quantification were, expressed in microg/g of dry weight, 0.0163 and 0.0085 for total and hexavalent chromium, respectively. The precision of the instrumental method for total Cr and Cr(VI) was lower than 1.6%, and for the analytical method, it was lower than 10%. The accuracy of the method for Cr(VI) quantification was evaluated by the standard additions method, with the recoveries being higher than 90% for all of the added concentrations. For total Cr, certified reference materials (lichen CRM 482 and soil sample NCS ZC73001) were used. An interference study was also carried out in a mushroom simulated matrix, and it was verified that the deviations of the expected values were lower than 4.0% for both total Cr and Cr(VI). The validated method was applied to the evaluation of total Cr and Cr(VI) in 34 wild mushrooms and 34 respective underlying soil samples collected in two different regions of Portugal (Beira Interior and TrAs-os-Montes), with different locations regarded as noncontaminated or contaminated areas. The species were identified by a mycologist and subdivided into 10 genera and 15 species: Amanita (rubescens, muscaria, and ponderosa), Boletus (regius), Lactarius (deliciosus, vellereus, and piperatus), Suillus (granulatus and luteus), Tricholoma (acerbum), Agaricus (sylvicola), Volvariella (gloiocephala), Lecopaxillus (giganteus), Macrolepiota (procera), and Psilocybe (fascicularis). The mean values found for total Cr were 1.14 and 1.11 microg/g of dry weight
Energetics and self-diffusion behavior of Zr atomic clusters on a Zr(0 0 0 1) surface

Energy Technology Data Exchange (ETDEWEB)

Liu Fusheng [Department of Applied Physics, Hunan University, Changsha 410082 (China); Hu Wangyu [Department of Applied Physics, Hunan University, Changsha 410082 (China)], E-mail: wangyuhu2001cn@yahoo.com.cn; Deng Huiqiu; Luo Wenhua; Xiao Shifang [Department of Applied Physics, Hunan University, Changsha 410082 (China); Yang Jianyu [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China)

2009-09-15

Using a molecular dynamics method and a modified analytic embedded atom potential, the energetic and the self-diffusion dynamics of Zr atomic clusters up to eight atoms on {alpha}-Zr(0 0 0 1) surface have been studied. The simulation temperature ranges from 300 to 1100 K and the simulation time varies from 20 to 40 ns. It's found that the heptamer and trimer are more stable comparing to other neighboring non-compact clusters. The diffusion coefficients of clusters are derived from the mean square displacement of cluster's mass-center and the present diffusion coefficients for clusters exhibit an Arrhenius behavior. The Arrhenius relation of the single adatom can be divided into two parts in different temperature range because of their different diffusion mechanisms. The migration energies of clusters increase with increasing the number of atoms in cluster. The differences of the prefactors also come from the diverse diffusion mechanisms. On the facet of 60 nm, the heptamer can be the nuclei in the crystal growth below 370 K.
Total sulfur determination in residues of crude oil distillation using FT-IR/ATR and variable selection methods

Science.gov (United States)

Müller, Aline Lima Hermes; Picoloto, Rochele Sogari; Mello, Paola de Azevedo; Ferrão, Marco Flores; dos Santos, Maria de Fátima Pereira; Guimarães, Regina Célia Lourenço; Müller, Edson Irineu; Flores, Erico Marlon Moraes

2012-04-01

Total sulfur concentration was determined in atmospheric residue (AR) and vacuum residue (VR) samples obtained from petroleum distillation process by Fourier transform infrared spectroscopy with attenuated total reflectance (FT-IR/ATR) in association with chemometric methods. Calibration and prediction set consisted of 40 and 20 samples, respectively. Calibration models were developed using two variable selection models: interval partial least squares (iPLS) and synergy interval partial least squares (siPLS). Different treatments and pre-processing steps were also evaluated for the development of models. The pre-treatment based on multiplicative scatter correction (MSC) and the mean centered data were selected for models construction. The use of siPLS as variable selection method provided a model with root mean square error of prediction (RMSEP) values significantly better than those obtained by PLS model using all variables. The best model was obtained using siPLS algorithm with spectra divided in 20 intervals and combinations of 3 intervals (911-824, 823-736 and 737-650 cm-1). This model produced a RMSECV of 400 mg kg-1 S and RMSEP of 420 mg kg-1 S, showing a correlation coefficient of 0.990.
Beams made of twisted atoms: A theoretical analysis

Energy Technology Data Exchange (ETDEWEB)

Hayrapetyan, Armen [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); Matula, Oliver [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Surzhykov, Andrey [Helmholtz-Institut Jena, 07743 Jena (Germany); Fritzsche, Stephan [Helmholtz-Institut Jena, 07743 Jena (Germany); Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universitaet Jena, 07743 Jena (Germany)

2014-07-01

We have analyzed Bessel beams of two-level atoms that are driven by a linearly polarized laser light. Based on the Schroedinger equation for two-level systems, we first determine the states of two-level atoms in a plane-wave field by taking into account propagation directions both of the atom and the field. For such laser-driven two-level atoms, we construct Bessel beams by going beyond the typical paraxial approximation. In particular, we show that the probability density of these atomic beams exhibits a non-trivial, Bessel-squared-type behavior. The profile of such twisted atoms is affected by atom and laser parameters, such as the nuclear charge, atom velocity, laser frequency, and propagation geometry of the atom and laser beams. Moreover, we spatially and temporally characterize the beam of hydrogen and selected (neutral) alkali-metal atoms that carry non-zero orbital angular momentum (OAM). The proposed spatiotemporal Bessel states (i) are able to describe twisted states of any two-level system which is driven by the radiation field and (ii) have potential applications in atomic and nuclear processes as well as in quantum communication.

Total Synthesis of Bryostatins. Development of Methodology for Atom-Economic and Stereoselective Synthesis of the C-ring Subunit

Science.gov (United States)

Trost, Barry M.; Frontier, Alison J.; Thiel, Oliver R.; Yang, Hanbiao; Dong, Guangbin

2012-01-01

Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for stereoselective assembly of the C-ring subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the C-ring subunit of bryostatins. PMID:21793057
Calculation of inelastic helium atom scattering from H2/ NaCl(001)

DEFF Research Database (Denmark)

Bruch, L.W.; Hansen, Flemming Yssing; Traeger, F.

2011-01-01

The one-phonon inelastic low energy helium atom scattering theory is adapted to cases where the target monolayer is a p(1 × 1) commensurate square lattice. Experimental data for para-H2/NaCl(001) are re-analyzed and the relative intensities of energy loss peaks in the range 6 to 9 meV are determi......The one-phonon inelastic low energy helium atom scattering theory is adapted to cases where the target monolayer is a p(1 × 1) commensurate square lattice. Experimental data for para-H2/NaCl(001) are re-analyzed and the relative intensities of energy loss peaks in the range 6 to 9 me...
Discrimination of solvent from protein regions in native Fouriers as a means of evaluating heavy-atom solutions in the MIR and MAD methods

International Nuclear Information System (INIS)

Terwilliger, Thomas C.; Berendzen, Joel

1999-01-01

The presence of distinct regions of high and low density variation in electron-density maps is found to be a good indicator of the correctness of a heavy-atom solution in the MIR and MAD methods. An automated examination of the native Fourier is tested as a means of evaluation of a heavy-atom solution in MAD and MIR methods for macromolecular crystallography. It is found that the presence of distinct regions of high and low density variation in electron-density maps is a good indicator of the correctness of a heavy-atom solution in the MIR and MAD methods. The method can be used to evaluate heavy-atom solutions during MAD and MIR structure solutions and to determine the handedness of the structure if anomalous data have been measured
On the road to metallic nanoparticles by rational design: bridging the gap between atomic-level theoretical modeling and reality by total scattering experiments

Science.gov (United States)

Prasai, Binay; Wilson, A. R.; Wiley, B. J.; Ren, Y.; Petkov, Valeri

2015-10-01

The extent to which current theoretical modeling alone can reveal real-world metallic nanoparticles (NPs) at the atomic level was scrutinized and demonstrated to be insufficient and how it can be improved by using a pragmatic approach involving straightforward experiments is shown. In particular, 4 to 6 nm in size silica supported Au100-xPdx (x = 30, 46 and 58) explored for catalytic applications is characterized structurally by total scattering experiments including high-energy synchrotron X-ray diffraction (XRD) coupled to atomic pair distribution function (PDF) analysis. Atomic-level models for the NPs are built by molecular dynamics simulations based on the archetypal for current theoretical modeling Sutton-Chen (SC) method. Models are matched against independent experimental data and are demonstrated to be inaccurate unless their theoretical foundation, i.e. the SC method, is supplemented with basic yet crucial information on the length and strength of metal-to-metal bonds and, when necessary, structural disorder in the actual NPs studied. An atomic PDF-based approach for accessing such information and implementing it in theoretical modeling is put forward. For completeness, the approach is concisely demonstrated on 15 nm in size water-dispersed Au particles explored for bio-medical applications and 16 nm in size hexane-dispersed Fe48Pd52 particles explored for magnetic applications as well. It is argued that when ``tuned up'' against experiments relevant to metals and alloys confined to nanoscale dimensions, such as total scattering coupled to atomic PDF analysis, rather than by mere intuition and/or against data for the respective solids, atomic-level theoretical modeling can provide a sound understanding of the synthesis-structure-property relationships in real-world metallic NPs. Ultimately this can help advance nanoscience and technology a step closer to producing metallic NPs by rational design.The extent to which current theoretical modeling alone can
Spontaneous excitation of a static multilevel atom coupled with electromagnetic vacuum fluctuations in Schwarzschild spacetime

International Nuclear Information System (INIS)

Zhou Wenting; Yu Hongwei

2012-01-01

We study the spontaneous excitation of a radially polarized static multilevel atom outside a spherically symmetric black hole in multipolar interaction with quantum electromagnetic fluctuations in the Boulware, Unruh and Hartle-Hawking vacuum states. We find that spontaneous excitation does not occur in the Boulware vacuum, and, in contrast to the scalar field case, the spontaneous emission rate is not well behaved at the event horizon as a result of the blow-up of the proper acceleration of the static atom. However, spontaneous excitation can take place both in the Unruh and the Hartle-Hawking vacua as if there were thermal radiation from the black hole. Distinctive features in contrast to the scalar field case are the existence of a term proportional to the proper acceleration squared in the rate of change of the mean atomic energy in the Unruh and the Hartle-Hawking vacua and the structural similarity in the spontaneous excitation rate between the static atoms outside a black hole and uniformly accelerated ones in a flat space with a reflecting boundary, which is particularly dramatic at the event horizon where a complete equivalence exists. (paper)
Two-dimensional atom localization via probe absorption in a four-level atomic system

International Nuclear Information System (INIS)

Wang Zhi-Ping; Ge Qiang; Ruan Yu-Hua; Yu Ben-Li

2013-01-01

We have investigated the two-dimensional (2D) atom localization via probe absorption in a coherently driven four-level atomic system by means of a radio-frequency field driving a hyperfine transition. It is found that the detecting probability and precision of 2D atom localization can be significantly improved via adjusting the system parameters. As a result, our scheme may be helpful in laser cooling or the atom nano-lithography via atom localization
Constrained least squares regularization in PET

International Nuclear Information System (INIS)

Choudhury, K.R.; O'Sullivan, F.O.

1996-01-01

Standard reconstruction methods used in tomography produce images with undesirable negative artifacts in background and in areas of high local contrast. While sophisticated statistical reconstruction methods can be devised to correct for these artifacts, their computational implementation is excessive for routine operational use. This work describes a technique for rapid computation of approximate constrained least squares regularization estimates. The unique feature of the approach is that it involves no iterative projection or backprojection steps. This contrasts with the familiar computationally intensive algorithms based on algebraic reconstruction (ART) or expectation-maximization (EM) methods. Experimentation with the new approach for deconvolution and mixture analysis shows that the root mean square error quality of estimators based on the proposed algorithm matches and usually dominates that of more elaborate maximum likelihood, at a fraction of the computational effort
Protein dynamics and stability: The distribution of atomic fluctuations in thermophilic and mesophilic dihydrofolate reductase derived using elastic incoherent neutron scattering

International Nuclear Information System (INIS)

Meinhold, Lars; Clement, David; Tehei, M.; Daniel, R.M.; Finney, J.L.; Smith, Jeremy C.

2008-01-01

The temperature dependence of the dynamics of mesophilic and thermophilic dihydrofolate reductase is examined using elastic incoherent neutron scattering. It is demonstrated that the distribution of atomic displacement amplitudes can be derived from the elastic scattering data by assuming a (Weibull) functional form that resembles distributions seen in molecular dynamics simulations. The thermophilic enzyme has a significantly broader distribution than its mesophilic counterpart. Furthermore, although the rate of increase with temperature of the atomic mean-square displacements extracted from the dynamic structure factor is found to be comparable for both enzymes, the amplitudes are found to be slightly larger for the thermophilic enzyme. Therefore, these results imply that the thermophilic enzyme is the more flexible of the two
Nonlinear Least Square Based on Control Direction by Dual Method and Its Application

Directory of Open Access Journals (Sweden)

Zhengqing Fu

2016-01-01

Full Text Available A direction controlled nonlinear least square (NLS estimation algorithm using the primal-dual method is proposed. The least square model is transformed into the primal-dual model; then direction of iteration can be controlled by duality. The iterative algorithm is designed. The Hilbert morbid matrix is processed by the new model and the least square estimate and ridge estimate. The main research method is to combine qualitative analysis and quantitative analysis. The deviation between estimated values and the true value and the estimated residuals fluctuation of different methods are used for qualitative analysis. The root mean square error (RMSE is used for quantitative analysis. The results of experiment show that the model has the smallest residual error and the minimum root mean square error. The new estimate model has effectiveness and high precision. The genuine data of Jining area in unwrapping experiments are used and the comparison with other classical unwrapping algorithms is made, so better results in precision aspects can be achieved through the proposed algorithm.
Square pulse current wave’s effect on electroplated nickel hardness

Directory of Open Access Journals (Sweden)

Bibian Alonso Hoyos

2006-09-01

Full Text Available The effects of frequency, average current density and duty cycle on the hardness of electroplated nickel were studied in Watts and sulphamate solutions by means of direct and square pulse current. The results in Watts’ solutions revealed greater hardness at low duty cycle, high average current density and high square pulse current frequency. There was little variation in hardness in nickel sulphamate solutions to changes in duty cycle and wave frequency. Hardness values obtained in the Watts’ bath with square pulse current were higher than those achieved with direct current at the same average current density; such difference was not significant in sulphamate bath treatment.
Systematics of atom-atom collision strengths at high speeds

International Nuclear Information System (INIS)

Gillespie, G.H.; Inokuti, M.

1980-01-01

The collision strengths for atom-atom collisions at high speeds are calculated in the first Born approximation. We studied four classes of collisions, distinguished depending upon whether each of the collision partners becomes excited or not. The results of numerical calculations of the collision strengths are presented for all neutral atoms with Z< or =18. The calculations are based on atomic form factors and incoherent scattering functions found in the literature. The relative contribution of each class of collision processes to the total collision cross section is examined in detail. In general, inelastic processes dominate for low-Z atoms, while elastic scattering is more important for large Z. Other systematics of the collision strengths are comprehensively discussed. The relevant experimental literature has been surveyed and the results of this work for the three collision systems H-He, He-He, and H-Ar are compared with the data for electron-loss processes. Finally, suggestions are made for future work in measurements of atom-atom and ion-atom collision cross sections
Identifying Dirac cones in carbon allotropes with square symmetry

Energy Technology Data Exchange (ETDEWEB)

Wang, Jinying [College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Huang, Huaqing; Duan, Wenhui [Department of Physics, Tsinghua University, Beijing 100084 (China); Liu, Zhirong, E-mail: LiuZhiRong@pku.edu.cn [College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); State Key Laboratory for Structural Chemistry of Unstable and Stable Species and Beijing National Laboratory for Molecular Sciences (BNLMS), Peking University, Beijing 100871 (China)

2013-11-14

A theoretical study is conducted to search for Dirac cones in two-dimensional carbon allotropes with square symmetry. By enumerating the carbon atoms in a unit cell up to 12, an allotrope with octatomic rings is recognized to possess Dirac cones under a simple tight-binding approach. The obtained Dirac cones are accompanied by flat bands at the Fermi level, and the resulting massless Dirac-Weyl fermions are chiral particles with a pseudospin of S = 1, rather than the conventional S = 1/2 of graphene. The spin-1 Dirac cones are also predicted to exist in hexagonal graphene antidot lattices.
Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

International Nuclear Information System (INIS)

Vos, M.; Marmitt, G. G.; Finkelstein, Y.; Moreh, R.

2015-01-01

Reflection electron energy loss spectra from some insulating materials (CaCO 3 , Li 2 CO 3 , and SiO 2 ) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO 2 , good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E gap ) 1.5 . For CaCO 3 , the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li 2 CO 3 (7.5 eV) is the first experimental estimate
MD simulation of atomic displacements in metals and metallic bilayers under low energy ion bombardment at 300 K

International Nuclear Information System (INIS)

Kornich, G.V.; Betz, G.; Bazhin, A.I.

1999-01-01

MD simulations of 100 eV Ar ion bombardment of (1 0 0) Ni and Al as well as Al/Ni bilayer crystals at 300 K have been performed and compared to previous calculations at 0 K. The Al/Ni bilayer crystal consisted of one Al layer on a (1 0 0) Ni substrate. Sputtering yields for Ni and Al/Ni show no temperature dependence, while for Al a pronounced increase with temperature was observed. The contributions of different mechanisms to the production of surface and bulk defects are discussed. The mean square displacement (MSD) of atoms is in all cases larger at 300 K as compared to 0 K. The larger MSD at 300 K is mainly due to an increase in lateral (perpendicular to the ion beam) motion of displaced atoms. Similar the number of atomic jumps, in which an atom leaves its original Wigner-Seitz cell, increases in all cases with temperature. For the pure elements the production of bulk vacancies and interstitials decreases with temperature, but the number of surface vacancies and ad-atoms increases with temperature. For the bilayer system practically no temperature dependence for defects was observed
A new zinc(II supramolecular square: Synthesis, crystal structure, thermal behavior and luminescence

Directory of Open Access Journals (Sweden)

Wang Xiu-Yan

2015-01-01

Full Text Available A new square-shaped Zn(II complex, namely, [Zn4(L4(phen4]•6H2O (1 (L = 2-hydroxynicotinate and phen = 1,10- phenanthroline, has been synthesized under hydrothermal condition. The crystal of 1 belongs to triclinic, space group P -1 with a = 10.773(2 Å, b = 12.641(3 Å, c = 13.573(3 Å, α = 107.44(3º, β = 102.66(3º, γ = 93.89(3°, C72H56N12O18Zn4, Mr = 1638.77, V = 1702.8(6 Å3 , Z = 1, Dc = 1.598 g/cm3 , S = 1.045, μ(MoKα = 1.475 mm-1 , F(000 = 836, R = 0.0472 and wR = 0.0919. In 1, four L ligands bridge four Zn(II atoms to form a square-shaped structure, where four phen ligands are respectively located on four corners of the square. The π-π stacking interactions extend the adjacent squares into a 1D supramolecular chain. The thermal behavior of 1 has been characterized. Moreover, its solid state luminescence property has been studied at room temperature.
Elucidating fluctuating diffusivity in center-of-mass motion of polymer models with time-averaged mean-square-displacement tensor

Science.gov (United States)

Miyaguchi, Tomoshige

2017-10-01

There have been increasing reports that the diffusion coefficient of macromolecules depends on time and fluctuates randomly. Here a method is developed to elucidate this fluctuating diffusivity from trajectory data. Time-averaged mean-square displacement (MSD), a common tool in single-particle-tracking (SPT) experiments, is generalized to a second-order tensor with which both magnitude and orientation fluctuations of the diffusivity can be clearly detected. This method is used to analyze the center-of-mass motion of four fundamental polymer models: the Rouse model, the Zimm model, a reptation model, and a rigid rodlike polymer. It is found that these models exhibit distinctly different types of magnitude and orientation fluctuations of diffusivity. This is an advantage of the present method over previous ones, such as the ergodicity-breaking parameter and a non-Gaussian parameter, because with either of these parameters it is difficult to distinguish the dynamics of the four polymer models. Also, the present method of a time-averaged MSD tensor could be used to analyze trajectory data obtained in SPT experiments.
Association of Supergranule Mean Scales with Solar Cycle Strengths and Total Solar Irradiance

Energy Technology Data Exchange (ETDEWEB)

Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, Dipankar, E-mail: sudip@iiap.res.in [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

2017-07-20

We analyze the long-term behavior of the supergranule scale parameter, in active regions (ARs) and quiet regions (QRs), using the Kodaikanal digitized data archive. This database provides century-long daily full disk observations of the Sun in Ca ii K wavelengths. In this paper, we study the distributions of the supergranular scales, over the whole data duration, which show identical shape in these two regimes. We found that the AR mean scale values are always higher than that of the QR for every solar cycle. The mean scale values are highly correlated with the sunspot number cycle amplitude and also with total solar irradiance (TSI) variations. Such a correlation establishes the cycle-wise mean scale as a potential calibrator for the historical data reconstructions. We also see an upward trend in the mean scales, as has already been reported in TSI. This may provide new input for climate forcing models. These results also give us insight into the different evolutionary scenarios of the supergranules in the presence of strong (AR) and weak (QR) magnetic fields.
First-Order Quantum Phase Transition for Dicke Model Induced by Atom-Atom Interaction

International Nuclear Information System (INIS)

Zhao Xiu-Qin; Liu Ni; Liang Jiu-Qing

2017-01-01

In this article, we use the spin coherent state transformation and the ground state variational method to theoretically calculate the ground function. In order to consider the influence of the atom-atom interaction on the extended Dicke model’s ground state properties, the mean photon number, the scaled atomic population and the average ground energy are displayed. Using the self-consistent field theory to solve the atom-atom interaction, we discover the system undergoes a first-order quantum phase transition from the normal phase to the superradiant phase, but a famous Dicke-type second-order quantum phase transition without the atom-atom interaction. Meanwhile, the atom-atom interaction makes the phase transition point shift to the lower atom-photon collective coupling strength. (paper)
AUTOMATIC EXTRACTION OF ROCK JOINTS FROM LASER SCANNED DATA BY MOVING LEAST SQUARES METHOD AND FUZZY K-MEANS CLUSTERING

Directory of Open Access Journals (Sweden)

S. Oh

2012-09-01

Full Text Available Recent development of laser scanning device increased the capability of representing rock outcrop in a very high resolution. Accurate 3D point cloud model with rock joint information can help geologist to estimate stability of rock slope on-site or off-site. An automatic plane extraction method was developed by computing normal directions and grouping them in similar direction. Point normal was calculated by moving least squares (MLS method considering every point within a given distance to minimize error to the fitting plane. Normal directions were classified into a number of dominating clusters by fuzzy K-means clustering. Region growing approach was exploited to discriminate joints in a point cloud. Overall procedure was applied to point cloud with about 120,000 points, and successfully extracted joints with joint information. The extraction procedure was implemented to minimize number of input parameters and to construct plane information into the existing point cloud for less redundancy and high usability of the point cloud itself.
Classification of Ultrasonic NDE Signals Using the Expectation Maximization (EM) and Least Mean Square (LMS) Algorithms

International Nuclear Information System (INIS)

Kim, Dae Won

2005-01-01

Ultrasonic inspection methods are widely used for detecting flaws in materials. The signal analysis step plays a crucial part in the data interpretation process. A number of signal processing methods have been proposed to classify ultrasonic flaw signals. One of the more popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature spare. This paper describes an alternative approach which uses the least mean square (LMS) method and exportation maximization (EM) algorithm with the model based deconvolution which is employed for classifying nondestructive evaluation (NDE) signals from steam generator tubes in a nuclear power plant. The signals due to cracks and deposits are not significantly different. These signals must be discriminated to prevent from happening a huge disaster such as contamination of water or explosion. A model based deconvolution has been described to facilitate comparison of classification results. The method uses the space alternating generalized expectation maximiBation (SAGE) algorithm ill conjunction with the Newton-Raphson method which uses the Hessian parameter resulting in fast convergence to estimate the time of flight and the distance between the tube wall and the ultrasonic sensor. Results using these schemes for the classification of ultrasonic signals from cracks and deposits within steam generator tubes are presented and showed a reasonable performances

Should total landings be used to correct estimated catch in numbers or mean-weight-at-age?

DEFF Research Database (Denmark)

Lewy, Peter; Lassen, H.

1997-01-01

Many ICES fish stock assessment working groups have practised Sum Of Products, SOP, correction. This correction stems from a comparison of total weights of the known landings and the SOP over age of catch in number and mean weight-at-age, which ideally should be identical. In case of SOP...... discrepancies some countries correct catch in numbers while others correct mean weight-at-age by a common factor, the ratio between landing and SOP. The paper shows that for three sampling schemes the SOP corrections are statistically incorrect and should not be made since the SOP is an unbiased estimate...... of the total landings. Calculation of the bias of estimated catch in numbers and mean weight-at-age shows that SOP corrections of either of these estimates may increase the bias. Furthermore, for five demersal and one pelagic North Sea species it is shown that SOP discrepancies greater than 2% from...
2S-4S spectroscopy in hydrogen atom: The new value for the Rydberg constant and the proton charge radius

Science.gov (United States)

Kolachevsky, N.; Beyer, A.; Maisenbacher, L.; Matveev, A.; Pohl, R.; Khabarova, K.; Grinin, A.; Lamour, T.; Yost, D. C.; Haensch, T. W.; Udem, Th.

2018-02-01

The core of the "proton radius puzzle" is the discrepancy of four standard deviations between the proton root mean square charge radii (rp) determined from regular hydrogen (H), and the muonic hydrogen atom (μp). We have measured the 2S-4P transition frequency in H, utilizing a cryogenic beam of H and directly demonstrate that quantum interference of neighboring atomic resonances can lead to line shifts much larger than the proton radius discrepancy. Using an asymmetric fit function we obtain rp = 0.8335(95) fm and the Rydberg constant R∞ = 10 973 731.568 076 (96) m-1. The new value for rp is 3.3 combined standard deviations smaller than the latest CODATA value, but in good agreement with the value from μp.
Total β-decay energies and atomic masses in regions far from β-stability

International Nuclear Information System (INIS)

Aleklett, K.

1977-01-01

This thesis is a summary of experimental investigations on total β-decay energies and deduced atomic masses of nuclei far from the region of β-stability. The Qsub(β) values are given for isotopes of Zn, Ga, Ge, As, Br, Rb, In, Sn, Sb, Te, Cs, Fr, Ra and Ac, with β-unstable nuclei. These unstable nuclei have very short half-lives, often below 10s, and the experimental techniques for the production, separation and collection of these short-lived nuclei are described. Neutron deficient nuclides were produced by spallation, in the ISOLDE facility, and neutron deficient nuclides were produced by thermal neutron induced fission of 235 U in the OSIRIS facility. β-spectra were recorded using an Si(Li)-detector and a coincidence system. Qsub(β) values obtained from mass formulae have been compared with experimental values obtained in different mass regions and a comparison made between results obtained from different droplet mass formulae. (B.D.)
Atomic physics using relativistic H- beams

International Nuclear Information System (INIS)

Bryant, H.C.

2005-01-01

Full text: An 8 GeV hydrogen atom can traverse a focused laser beam of width of 1 micron in a time of 353 attoseconds in its rest frame. A design is currently underway at Fermilab for a superconducting linear accelerator that will accelerate H - ions to 8 GeV. This 'Proton Driver' beam is intended to be injected, after stripping down to protons, into the 120 GeV Main Injector for the mass production of neutrinos aimed at a neutrino detector (MINOS) in a mine shaft in Soudan, Minnesota (USA) for the study of neutrino oscillations. It has not passed unnoticed that with some advance planning a few nanoamps from the up-to-250 mA beam could be diverted for atomic physics experiments. Relativistic kinematics enable the creation of extreme conditions for a beam atom. For example, the Doppler shift allows a very large tuning range in the atom's rest frame of a laser beam that is fixed- frequency in the lab. At 8 GeV the rest frame Doppler shift ranges from a factor of 19 in the forward direction to 0.05 backward. The laser intensity is enhanced by the square of the Doppler shift, so that the world's most intense laser beam would be amplified by a factor of 360 in the atom's rest frame. Furthermore, although there are extreme changes in the frequency and intensity in the atom's frame as one changes the intersection angle, the ponderomotive potential remains constant, as it is a relativistic invariant. One of the interesting problems that arises in the planning for this accelerator is the stripping of electrons from the negative ions by photodetachment from Doppler shifted thermal photons. We estimate that, if the transfer lines are kept at 300 K (room temperature), the mean free path at 8 GeV for stripping from collisions with cavity radiation is about 1300 km. The physics of the interactions of such a beam with very thin material foils, again in the attosecond regime, has been treated theoretically, but has not been studied experimentally at such high energies. We will
Electronic structure of atoms: atomic spectroscopy information system

International Nuclear Information System (INIS)

Kazakov, V V; Kazakov, V G; Kovalev, V S; Meshkov, O I; Yatsenko, A S

2017-01-01

The article presents a Russian atomic spectroscopy, information system electronic structure of atoms (IS ESA) (http://grotrian.nsu.ru), and describes its main features and options to support research and training. The database contains over 234 000 records, great attention paid to experimental data and uniform filling of the database for all atomic numbers Z, including classified levels and transitions of rare earth and transuranic elements and their ions. Original means of visualization of scientific data in the form of spectrograms and Grotrian diagrams have been proposed. Presentation of spectral data in the form of interactive color charts facilitates understanding and analysis of properties of atomic systems. The use of the spectral data of the IS ESA together with its functionality is effective for solving various scientific problems and training of specialists. (paper)
Electronic structure of atoms: atomic spectroscopy information system

Science.gov (United States)

Kazakov, V. V.; Kazakov, V. G.; Kovalev, V. S.; Meshkov, O. I.; Yatsenko, A. S.

2017-10-01

The article presents a Russian atomic spectroscopy, information system electronic structure of atoms (IS ESA) (http://grotrian.nsu.ru), and describes its main features and options to support research and training. The database contains over 234 000 records, great attention paid to experimental data and uniform filling of the database for all atomic numbers Z, including classified levels and transitions of rare earth and transuranic elements and their ions. Original means of visualization of scientific data in the form of spectrograms and Grotrian diagrams have been proposed. Presentation of spectral data in the form of interactive color charts facilitates understanding and analysis of properties of atomic systems. The use of the spectral data of the IS ESA together with its functionality is effective for solving various scientific problems and training of specialists.
Atom localization via controlled spontaneous emission in a five-level atomic system

International Nuclear Information System (INIS)

Wang Zhiping; Yu Benli; Zhu Jun; Cao Zhigang; Zhen Shenglai; Wu Xuqiang; Xu Feng

2012-01-01

We investigate the one- and two-dimensional atom localization behaviors via spontaneous emission in a coherently driven five-level atomic system by means of a radio-frequency field driving a hyperfine transition. It is found that the detecting probability and precision of atom localization behaviors can be significantly improved via adjusting the system parameters. More importantly, the two-dimensional atom localization patterns reveal that the maximal probability of finding an atom within the sub-wavelength domain of the standing waves can reach unity when the corresponding conditions are satisfied. As a result, our scheme may be helpful in laser cooling or the atom nano-lithography via atom localization. - Highlights: ► One- and two-dimensional atom localization behaviors via spontaneous emission in five-level atoms are investigated. ► An assisting radio-frequency field is used to control the atom localization behaviors. ► High-precision and high-resolution two-dimensional atom localization can be realized in this scheme.
The influence of gas phase velocity fluctuations on primary atomization and droplet deformation

Science.gov (United States)

Kourmatzis, A.; Masri, A. R.

2014-02-01

The effects of grid-generated velocity fluctuations on the primary atomization and subsequent droplet deformation of a range of laminar liquid jets are examined using microscopic high-speed backlit imaging of the break-up zone and laser Doppler anemometry of the gas phase separately. This is done for fixed gas mean flow conditions in a miniature wind tunnel experiment utilizing a selection of fuels, turbulence-generating grids and two syringe sizes. The constant mean flow allows for an isolated study of velocity fluctuation effects on primary atomization in a close approximation to homogeneous decaying turbulence. The qualitative morphology of the primary break-up region is examined over a range of turbulence intensities, and spectral analysis is performed in order to ascertain the break-up frequency which, for a case of no grid, compares well with the existing literature. The addition of velocity fluctuations tends to randomize the break-up process. Slightly downstream of the break-up region, image processing is conducted in order to extract a number of metrics, which do not depend on droplet sphericity, and these include droplet aspect ratio and orientation, the latter quantity being somewhat unconventional in spray characterization. A turbulent Weber number which takes into account gas phase fluctuations is utilized to characterize the resulting droplet shapes, in addition to a mean Weber number . Above a a clear positive relationship exists between the mean aspect ratio of droplets and the turbulent Weber number where is varied by altering all relevant variables including the velocity root mean square, the initial droplet diameter, the surface tension and the density.
Measurement of the size of spherical nanoparticles by means of atomic force microscopy

International Nuclear Information System (INIS)

Couteau, O; Roebben, G

2011-01-01

Several techniques are nowadays available to determine the size distribution of nanoparticulate matter. Among these techniques, atomic force microscopy (AFM) is especially valuable because it can provide three-dimensional information on the shape of individual nanoparticles. This paper describes a new method to determine the size distribution of a population of spherical nanoparticles deposited on a hard substrate. The method is based on the acquisition and analysis of topographical AFM images. The size of individual nanoparticles is obtained by fitting the topographical region associated with the nanoparticle with a sphere. Tests on model systems based on nanoparticle reference materials consisting of polystyrene (PS) latex suspensions show promising results. The measured mean particle size is larger than the reference value, but this is a predictable effect of the AFM tip shape. Tests on a bi-modal mixture of two PS latex reference materials show the impact of the quality of the dispersion of the nanoparticles on the results obtained with the new technique
Schwinger variational calculation of ionization of hydrogen atoms for ...

Indian Academy of Sciences (India)

Schwinger variational calculation of ionization of hydrogen atoms for large momentum transfers. K CHAKRABARTI. Department of Mathematics, Scottish Church College, 1 & 3 Urquhart Square,. Kolkata 700 006, India. MS received 7 July 2001; revised 10 October 2001. Abstract. Schwinger variational principle is used here ...
Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

Energy Technology Data Exchange (ETDEWEB)

Vos, M. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Marmitt, G. G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Finkelstein, Y. [Nuclear Research Center — Negev, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

2015-09-14

Reflection electron energy loss spectra from some insulating materials (CaCO{sub 3}, Li{sub 2}CO{sub 3}, and SiO{sub 2}) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO{sub 2}, good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E{sub gap}){sup 1.5}. For CaCO{sub 3}, the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li{sub 2}CO{sub 3} (7.5 eV) is the first experimental estimate.
A model for the interaction between F centers and H atoms in ionic crystals

International Nuclear Information System (INIS)

Dumke, V.R.; Souza, M. de

1975-01-01

The interaction between an F center and neutral hydrogen atoms, the most simple paramagnetic defects in ionic crystals, is described in terms of a perturbation theory of two square potential wells. The good agreement with experimental data indicates that lattice distortion due to the presence of the hydrogen atoms is negligible [pt
SU-E-J-249: Correlation of Mean Lung Ventilation Value with Ratio of Total Lung Volumes

International Nuclear Information System (INIS)

Yu, N; Qu, H; Xia, P

2014-01-01

Purpose: Lung ventilation function measured from 4D-CT and from breathing correlated CT images is a novel concept to incorporate the lung physiologic function into treatment planning of radiotherapy. The calculated ventilation functions may vary from different breathing patterns, affecting evaluation of the treatment plans. The purpose of this study is to correlate the mean lung ventilation value with the ratio of the total lung volumes obtained from the relevant CTs. Methods: A ventilation map was calculated from the variations of voxel-to-voxel CT densities from two breathing phases from either 4D-CT or breathing correlated CTs. An open source image registration tool of Plastimatch was used to deform the inhale phase images to the exhale phase images. To calculate the ventilation map inside lung, the whole lung was delineated and the tissue outside the lung was masked out. With a software tool developed in house, the 3D ventilation map was then converted in the DICOM format associated with the planning CT images. The ventilation map was analyzed on a clinical workstation. To correlate ventilation map thus calculated with lung volume change, the total lung volume change was compared the mean ventilation from our method. Results: Twenty two patients who underwent stereotactic body irradiation for lung cancer was selected for this retrospective study. For this group of patients, the ratio of lung volumes for the inhale (Vin ) and exhale phase (Vex ) was shown to be linearly related to the mean of the local ventilation (Vent), Vin/Vex=1.+0.49*Vent (R2=0.93, p<0.01). Conclusion: The total lung volume change is highly correlated with the mean of local ventilation. The mean of local ventilation may be useful to assess the patient's lung capacity
Digital squares

DEFF Research Database (Denmark)

Forchhammer, Søren; Kim, Chul E

1988-01-01

Digital squares are defined and their geometric properties characterized. A linear time algorithm is presented that considers a convex digital region and determines whether or not it is a digital square. The algorithm also determines the range of the values of the parameter set of its preimages....... The analysis involves transforming the boundary of a digital region into parameter space of slope and y-intercept...
Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO3)n films by means of metalorganic aerosol deposition

International Nuclear Information System (INIS)

Jungbauer, M.; Hühn, S.; Moshnyaga, V.; Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.

2014-01-01

We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO 3 ) n (n = ∞, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO 3 (001) substrates by means of a sequential deposition of Sr-O/Ti-O 2 atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO 3 ) 4 block at the level of 2.4%. This identifies the SrTiO 3 substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy
AtomPy: A Cloud Atomic-data Service for Astrophysical Applications

Science.gov (United States)

Mendoza, Claudio; Boswell, J. S.; Bautista, M.

2013-06-01

Apart from our long-term commitment to the computing of accurate atomic data for astrophysical applications, we have also been interested in the problems of data access and dissemination. In this respect, one of us took part in the developments of TIPTOPbase [1, 2, 3], the astrophysical opacity server referred to as OPserver [4, 5], and, more recently, of the Virtual Atomic and Molecular Data Center [6, 7]. Our present effort is now with the establishment of a cloud atomic data web service, AtomPy, implemented by means of SOAP web services, Google Drive spreadsheets and Python modules. In the present poster we will describe the outline of this ambitious project, illustrated with some prototypes that are already operational.
Characteristics of Fluid Force Reduction for Two Different Square Prisms in a Tandem Arrangement

Energy Technology Data Exchange (ETDEWEB)

Ro, Ki Deok; Kang, Chang Whan; Park, Kwon Ho [Gyeongsang Nat’l Univ., Jinju (Korea, Republic of)

2017-07-15

The Characteristics of the flow fields of a square prism having a small square prism were investigated by measuring of lift and drag on the square prism and visualizing the flow field using PIV. The experimental parameters were the width ratios(H/B=0.2~0.6) of small square prisms to the prism width and the gap ratios (G/B=0~3) between the prism and the small square prism. The drag reduction rate of the square prism initially increased and then decreased with the G/B ratio for the same H/B ratio, and increased with the H/B ratio for the same G/B ratio. The maximum drag reduction rate of 98.0% was observed at H/B=0.6 and G/B=1.0. The lift reduction rate of the square prism was not affected by the width and gap ratios; the total average value was approximately 66.5%. In case of a square prism having a small square prism, the stagnation regions were represented in the upstream and downstream sides of the square prism.
Determination of total tin in silicate rocks by graphite furnace atomic absorption spectrometry

Science.gov (United States)

Elsheimer, H.N.; Fries, T.L.

1990-01-01

A method is described for the determination of total tin in silicate rocks utilizing a graphite furnace atomic absorption spectrometer with a stabilized-temperature platform furnace and Zeeman-effect background correction. The sample is decomposed by lithium metaborate fusion (3 + 1) in graphite crucibles with the melt being dissolved in 7.5% hydrochloric acid. Tin extractions (4 + 1 or 8 + 1) are executed on portions of the acid solutions using a 4% solution of tricotylphosphine oxide in methyl isobutyl ketone (MIBK). Ascorbic acid is added as a reducing agent prior to extraction. A solution of diammonium hydrogenphosphate and magnesium nitrate is used as a matrix modifier in the graphite furnace determination. The limit of detection is > 10 pg, equivalent to > 1 ??g l-1 of tin in the MIBK solution or 0.2-0.3 ??g g-61 in the rock. The concentration range is linear between 2.5 and 500 ??g l-1 tin in solution. The precision, measured as relative standard deviation, is < 20% at the 2.5 ??g l-1 level and < 7% at the 10-30 ??g l-1 level of tin. Excellent agreement with recommended literature values was found when the method was applied to the international silicate rock standards BCR-1, PCC-1, GSP-1, AGV-1, STM-1, JGb-1 and Mica-Fe. Application was made to the determination of tin in geological core samples with total tin concentrations of the order of 1 ??g g-1 or less.
An information geometric approach to least squares minimization

Science.gov (United States)

Transtrum, Mark; Machta, Benjamin; Sethna, James

2009-03-01

Parameter estimation by nonlinear least squares minimization is a ubiquitous problem that has an elegant geometric interpretation: all possible parameter values induce a manifold embedded within the space of data. The minimization problem is then to find the point on the manifold closest to the origin. The standard algorithm for minimizing sums of squares, the Levenberg-Marquardt algorithm, also has geometric meaning. When the standard algorithm fails to efficiently find accurate fits to the data, geometric considerations suggest improvements. Problems involving large numbers of parameters, such as often arise in biological contexts, are notoriously difficult. We suggest an algorithm based on geodesic motion that may offer improvements over the standard algorithm for a certain class of problems.
The application of root mean square electrocardiography (RMS ECG) for the detection of acquired and congenital long QT syndrome.

Science.gov (United States)

Lux, Robert L; Sower, Christopher Todd; Allen, Nancy; Etheridge, Susan P; Tristani-Firouzi, Martin; Saarel, Elizabeth V

2014-01-01

Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS). RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II. All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3. These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements.

Ordinance on the Implementation of Atomic Safety and Radiation Protection

International Nuclear Information System (INIS)

1984-01-01

In execution of the new Atomic Energy Act the Ordinance on the Implementation of Atomic Safety and Radiation Protection was put into force on 1 February 1985. It takes into account all forms of peaceful nuclear energy and ionizing radiation uses in nuclear installations, irradiation facilities and devices in research, industries, and health services, and in radioactive isotope production and laboratories. It covers all aspects of safety and protection and defines atomic safety as nuclear safety and nuclear safeguards and physical protection of nuclear materials and facilities, whereas radiation protection includes the total of requirements, measures, means and methods necessary to protect man and the environment from the detrimental effects of ionizing radiation. It has been based on ICRP Recommendation No. 26 and the IAEA's Basic Safety Standards and supersedes the Radiation Protection Ordinance of 1969
Comment on "Relative variance of the mean squared pressure in multimode media: rehabilitating former approaches" [J. Acoust. Soc. Am. 136, 2621-2629 (2014)].

Science.gov (United States)

Davy, John L; Weaver, Richard L

2015-03-01

Models for the statistics of responses in finite reverberant structures, and in particular, for the variance of the mean square pressure in reverberation rooms, have been studied for decades. It is therefore surprising that a recent communication has claimed that the literature has gotten the simplest of such calculations very wrong. Monsef, Cozza, Rodrigues, Cellard, and Durocher [(2014). J. Acoust. Soc. Am. 136, 2621-2629] have derived a modal-based expression for the relative variance that differs significantly from expressions that have been accepted since 1969. This Comment points out that the Monsef formula is clearly incorrect, and then for the interested reader, points out the subtle place where they made their mistake.
Breaking the atom with Samson

NARCIS (Netherlands)

Väänänen, J.; Coecke, B.; Ong, L.; Panangaden, P.

2013-01-01

The dependence atom =(x,y) was introduced in [11]. Here x and y are finite sets of attributes (or variables) and the intuitive meaning of =(x,y) is that the attributes x completely (functionally) determine the attributes y. One may wonder, whether the dependence atom is truly an atom or whether it
Estimation of lead, cadmium and nickel content by means of Atomic Absorption Spectroscopy in dry fruit bodies of some macromycetes growing in Poland. II.

Directory of Open Access Journals (Sweden)

Jan Grzybek

2014-08-01

Full Text Available The content of lead, cadmium, and nickel in dry fruit bodies of 34 species of macromyoetes collected in Poland from 72 natural babitats by means of Atomic Absorption Spectroscopy (AAS was estimated.
Augmented GNSS Differential Corrections Minimum Mean Square Error Estimation Sensitivity to Spatial Correlation Modeling Errors

Directory of Open Access Journals (Sweden)

Nazelie Kassabian

2014-06-01

Full Text Available Railway signaling is a safety system that has evolved over the last couple of centuries towards autonomous functionality. Recently, great effort is being devoted in this field, towards the use and exploitation of Global Navigation Satellite System (GNSS signals and GNSS augmentation systems in view of lower railway track equipments and maintenance costs, that is a priority to sustain the investments for modernizing the local and regional lines most of which lack automatic train protection systems and are still manually operated. The objective of this paper is to assess the sensitivity of the Linear Minimum Mean Square Error (LMMSE algorithm to modeling errors in the spatial correlation function that characterizes true pseudorange Differential Corrections (DCs. This study is inspired by the railway application; however, it applies to all transportation systems, including the road sector, that need to be complemented by an augmentation system in order to deliver accurate and reliable positioning with integrity specifications. A vector of noisy pseudorange DC measurements are simulated, assuming a Gauss-Markov model with a decay rate parameter inversely proportional to the correlation distance that exists between two points of a certain environment. The LMMSE algorithm is applied on this vector to estimate the true DC, and the estimation error is compared to the noise added during simulation. The results show that for large enough correlation distance to Reference Stations (RSs distance separation ratio values, the LMMSE brings considerable advantage in terms of estimation error accuracy and precision. Conversely, the LMMSE algorithm may deteriorate the quality of the DC measurements whenever the ratio falls below a certain threshold.
Differential cross section of atomic hydrogen photoionization

International Nuclear Information System (INIS)

Kondratovich, V.D.; Ostrovskij, V.N.

1986-01-01

Differential cross-section of atomic hydrogen photoeffect in external electric field was investigated in semiclassical approximation. Interference was described. It occurred due to the fact that infinite number of photoelectron trajectories leads to any point of classically accessible motion region. Interference picture can reach macroscopic sizes. The picture is determined by location of function nodes, describing finite electron motion along one of parabolic coordinates. The squares of external picture rings are determined only by electric field intensity in the general case at rather high energies. Quantum expression for photocurrent density was obtained using Green function in superposition of Coulomb and uniform field as well as semiclassical approximation. Possible applications of macroscopic interference picture to specification of atom ionization potentials, selective detection of atoms or particular molecules, as well as weak magnetic field and observation of Aaronov-Bom effect are discussed
Elementary Atom Interaction with Matter

OpenAIRE

Mrowczynski, Stanislaw

1998-01-01

The calculations of the elementary atom (the Coulomb bound state of elementary particles) interaction with the atom of matter, which are performed in the Born approximation, are reviewed. We first discuss the nonrelativistic approach and then its relativistic generalization. The cross section of the elementary atom excitation and ionization as well as the total cross section are considered. A specific selection rule, which applies for the atom formed as positronium by particle-antiparticle pa...
Total ozone retrieval from satellite multichannel filter radiometer measurements

International Nuclear Information System (INIS)

Lovill, J.E.; Sullivan, T.J.; Weichel, R.L.; Ellis, J.S.; Huebel, J.G.; Korver, J.; Weidhaas, P.P.; Phelps, F.A.

1978-01-01

A total ozone retrieval model has been developed to process radiance data gathered by a satellite-mounted multichannel filter radiometer (MFR). Extensive effort went into theoretical radiative transfer modeling, a retrieval scheme was developed, and the technique was applied to the MFR radiance measurements. The high quality of the total ozone retrieval results was determined through comparisons with Dobson measurements. Included in the report are global total ozone maps for 20 days between May 12 and July 5, 1977. A comparison of MFR results for 13 days in June 1977 with Dobson spectrophotometer measurements of ozone for the same period showed good agreement: there was a root-mean-square difference of 6.2% (equivalent to 20.2 m.atm.cm). The estimated global total ozone value for June 1977 (296 m.atm.cm) was in good agreement with satellite backscatter ultraviolet data for June 1970 (304 m.atm.cm) and June 1971
Generation of a slow and continuous cesium atomic beam for an atomic clock

International Nuclear Information System (INIS)

Park, Sang Eon; Lee, Ho Seong; Shin, Eun-joo; Kwon, Taeg Yong; Yang, Sung Hoon; Cho, Hyuck

2002-01-01

A thermal atomic beam from a cesium oven was slowed down by use of the Hoffnagle modified white-light cooling technique. In addition, the atomic beam was collimated by use of a two-dimensional optical molasses that was installed transverse to the atomic-beam direction. The flux of the atomic beam was 2x10 10 atoms/s, an increase of a factor of 16 as a result of the collimation. The mean longitudinal velocity was ∼24.4 m/s, and the rms velocity spread of the slowed atomic beam was ∼1 m/s. Compared with other methods, we found that the Hoffnagle method is suitable for the generation of slow atomic beams to be used in an atomic clock, which requires an ultralow magnetic field environment. This atomic beam was deflected by an angle of 30 deg. by a one-dimensional optical molasses to separate it from laser light and high-velocity atoms
The mean field in many body quantum physics

International Nuclear Information System (INIS)

Llano, M. de

1984-01-01

As an introduction to the quantum problem of many bodies we present a panoramic view of the most elementary theories called mean field theories. They comprise: i) the fermions ideal gas theory which implies, in a simple manner, the stability of white dwarf stars and of neutron stars, ii) the Hartree-Fock approximation for thermodynamical systems which is presented here in the context of a liquid-crystal phase transition, and iii) the Thomas-Fermi theory which is applied to the total binding energy of neutral atoms. (author)
Cantilever contribution to the total electrostatic force measured with the atomic force microscope

International Nuclear Information System (INIS)

Guriyanova, Svetlana; Golovko, Dmytro S; Bonaccurso, Elmar

2010-01-01

The atomic force microscope (AFM) is a powerful tool for surface imaging at the nanometer scale and surface force measurements in the piconewton range. Among long-range surface forces, the electrostatic forces play a predominant role. They originate if the electric potentials of the substrate and of the tip of the AFM cantilever are different. A quantitative interpretation of the AFM signal is often difficult because it depends in a complicated fashion on the cantilever–tip–surface geometry. Since the electrostatic interaction is a long-range interaction, the cantilever, which is many microns from the surface, contributes to the total electrostatic force along with the tip. Here we present results of the electrostatic interaction between a conducting flat surface and horizontal or tilted cantilevers, with and without tips, at various distances from the surface. As addressed in a previous work, we show that the contribution of the cantilever to the overall force cannot be neglected. Based on a predictive model and on 3D confocal measurements, we discuss the influence of the tilting angle of the cantilever
Approximating the variance of estimated means for systematic random sampling, illustrated with data of the French Soil Monitoring Network

NARCIS (Netherlands)

Brus, D.J.; Saby, N.P.A.

2016-01-01

In France like in many other countries, the soil is monitored at the locations of a regular, square grid thus forming a systematic sample (SY). This sampling design leads to good spatial coverage, enhancing the precision of design-based estimates of spatial means and totals. Design-based
Determination of calibration equations by means of the generalized least squares method

International Nuclear Information System (INIS)

Zijp, W.L.

1984-12-01

For the determination of two-dimensional calibration curves (e.g. in tank calibration procedures) or of three dimensional calibration equations (e.g. for the calibration of NDA equipment for enrichment measurements) one performs measurements under well chosen conditions, where all observables of interest (inclusive the values of the standard material) are subject to measurement uncertainties. Moreover correlations in several measurements may occur. This document describes the mathematical-statistical approach to determine the values of the model parameters and their covariance matrix, which fit best to the mathematical model for the calibration equation. The formulae are based on the method of generalized least squares where the term generalized implies that non-linear equations in the unknown parameters and also covariance matrices of the measurement data of the calibration can be taken into account. In the general case an iteration procedure is required. No iteration is required when the model is linear in the parameters and the covariance matrices for the measurements of co-ordinates of the calibration points are proportional to each other
Production of a square geometry Americium standard source for use with photodiodes

Energy Technology Data Exchange (ETDEWEB)

Costa, Priscila; Geraldo, Bianca; Raele, Marcus P.; Marumo, Júlio T.; Vicente, Roberto; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: priscila3.costa@usp.br, E-mail: fredzini@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

In the development of a thermal neutron detector using a square photodiode and a thin boron film, a radioactive calibration source with the same geometry was needed. An americium-243 standard source was produced by electrodeposition aiming at the calibration of a PIN-type silicon photodiode with a detection area of 10 x 10 mm{sup 2}. To produce the samples two tests were performed. In the first test, a square stainless steel plate (10 x 10 mm{sup 2}) was fixed on the surface of the conventional plate, which was removed after deposition. To reduce the loss of activity of the source, in the second test nail polish was applied on the silver plate leaving only an area of 10 x 10 mm{sup 2} without varnish coating. Once the electrodeposition process was completed, the activity concentration measurement was performed by alpha particle spectrometry. The first method presented a lower activity when compared to the total activity of Am-243 added initially. For the second method, the total activity was concentrate in the exposed square region (without nail polish). The results showed that it is possible to obtain a square geometry source; furthermore, the surrounding nail polish was not contaminated by {sup 243}Am. The comparison of these two approaches indicated that the second method was more efficient as it was possible to concentrate all the americium activity in the delimited square area. (author)
Statistical properties of kinetic and total energy densities in reverberant spaces

DEFF Research Database (Denmark)

Jacobsen, Finn; Molares, Alfonso Rodriguez

2010-01-01

Many acoustical measurements, e.g., measurement of sound power and transmission loss, rely on determining the total sound energy in a reverberation room. The total energy is usually approximated by measuring the mean-square pressure (i.e., the potential energy density) at a number of discrete....... With the advent of a three-dimensional particle velocity transducer, it has become somewhat easier to measure total rather than only potential energy density in a sound field. This paper examines the ensemble statistics of kinetic and total sound energy densities in reverberant enclosures theoretically...... positions. The idea of measuring the total energy density instead of the potential energy density on the assumption that the former quantity varies less with position than the latter goes back to the 1930s. However, the phenomenon was not analyzed until the late 1970s and then only for the region of high...
Determination of total tin in geological materials by electrothermal atomic-absorption spectrophotometry using a tungsten-impregnated graphite furnace

Science.gov (United States)

Zhou, L.; Chao, T.T.; Meier, A.L.

1984-01-01

An electrothermal atomic-absorption spectrophotometric method is described for the determination of total tin in geological materials, with use of a tungsten-impregnated graphite furnace. The sample is decomposed by fusion with lithium metaborate and the melt is dissolved in 10% hydrochloric acid. Tin is then extracted into trioctylphosphine oxide-methyl isobutyl ketone prior to atomization. Impregnation of the furnace with a sodium tungstate solution increases the sensitivity of the determination and improves the precision of the results. The limits of determination are 0.5-20 ppm of tin in the sample. Higher tin values can be determined by dilution of the extract. Replicate analyses of eighteen geological reference samples with diverse matrices gave relative standard deviations ranging from 2.0 to 10.8% with an average of 4.6%. Average tin values for reference samples were in general agreement with, but more precise than, those reported by others. Apparent recoveries of tin added to various samples ranged from 95 to 111% with an average of 102%. ?? 1984.
Atomic politics

International Nuclear Information System (INIS)

Skogmar, G.

1979-01-01

The authors basic point is that the military and civil sides of atomic energy cannot be separated. The general aim of the book is to analyze both the military and civil branches, and the interdependence between them, of American foreign policy in the atomic field. Atomic policy is seen as one of the most important imstruments of foreign policy which, in turn, is seen against the background of American imperialism in general. Firstly, the book investigates the most important means by which the United States has controlled the development in the nuclear field in other countries. These means include influencing the conditions of access to nuclear resources of various kinds, influencing the flow of technical-economic information and influencing international organizations and treaties bearing on atomic energy. The time period treated is 1945-1973. 1973 is chosen as the end-year of the study mainly because of the new conditions in the whole energy field initiated by the oil crisis in that year. The sources of the empirical work are mainly hearings before the Joint Committee on Atomic Energy of the U.S. Congress and legal material of various kinds. Secondly, the goals of the American policy are analyzed. The goals identified are armament effect, non-proliferation (horizontal), sales, and energy dependence. The relation between the main goals is discussed.The discussion is centered on the interdependence between the military and the civil aspects, conflict and coincidence of various goals, the relation between short-term and long-term goals, and the possibilities of using one goal as pretext for another. Thirdly, some causes of the changes in the atomic policy around 1953 and 1963 are identified. These are the strategic balance, the competitive situation, the capacity (of the American atomic productive apparatus), and the nuclear technological stage. The specific composition of these four factors at the two time-points can explain the changes of policy. (author)
Determination of total selenium in nutritional supplements and selenised yeast by Zeeman-effect graphite furnace atomic absorption spectrometry

DEFF Research Database (Denmark)

Larsen, Erik Huusfeldt; Ekelund, J.

1989-01-01

A method for the determination of total selenium in nutritional supplements and selenised yeast is described. The samples were ashed in nitric acid. Hydrochloric acid was used to prevent precipitation of, in particular, iron salts. After appropriate dilutions, the selenium was determined by Zeeman......-effect background corrected graphite furnace atomic absorption spectrometry. A furnace ashing step at 1100 °C was necessary in order to obtain a total recovery of selenium when present in the organic form. Palladium nitrate-magnesium nitrate was used as a matrix modifier. Independent methods were used to determine...... the content of selenium in a selenised yeast check sample. Accuracy was assured using this sample and by recovery experiments. Between-day random error showed a coefficient of variation of 4.2%. Results from the analysis of eight different commercial supplements were in good agreement with declared contents....
Baseline correction combined partial least squares algorithm and its application in on-line Fourier transform infrared quantitative analysis.

Science.gov (United States)

Peng, Jiangtao; Peng, Silong; Xie, Qiong; Wei, Jiping

2011-04-01

In order to eliminate the lower order polynomial interferences, a new quantitative calibration algorithm "Baseline Correction Combined Partial Least Squares (BCC-PLS)", which combines baseline correction and conventional PLS, is proposed. By embedding baseline correction constraints into PLS weights selection, the proposed calibration algorithm overcomes the uncertainty in baseline correction and can meet the requirement of on-line attenuated total reflectance Fourier transform infrared (ATR-FTIR) quantitative analysis. The effectiveness of the algorithm is evaluated by the analysis of glucose and marzipan ATR-FTIR spectra. BCC-PLS algorithm shows improved prediction performance over PLS. The root mean square error of cross-validation (RMSECV) on marzipan spectra for the prediction of the moisture is found to be 0.53%, w/w (range 7-19%). The sugar content is predicted with a RMSECV of 2.04%, w/w (range 33-68%). Copyright © 2011 Elsevier B.V. All rights reserved.
Two-dimensional square ternary Cu2MX4 (M = Mo, W; X = S, Se) monolayers and nanoribbons predicted from density functional theory

KAUST Repository

Gan, Liyong

2014-03-19

Two-dimensional (2D) materials often adopt a hexagonal lattice. We report on a class of 2D materials, Cu2MX4 (M = Mo, W; X = S, Se), that has a square lattice. Up to three monolayers, the systems are kinetically stable. All of them are semiconductors with band gaps from 2.03 to 2.48 eV. Specifically, the states giving rise to the valence band maximum are confined to the Cu and X atoms, while those giving rise to the conduction band minimum are confined to the M atoms, suggesting that spontaneous charge separation occurs. The semiconductive nature makes the materials promising for transistors, optoelectronics, and solar energy conversion. Moreover, the ferromagnetism on the edges of square Cu2MX4 nanoribbons opens applications in spintronics.

Two-dimensional square ternary Cu2MX4 (M = Mo, W; X = S, Se) monolayers and nanoribbons predicted from density functional theory

KAUST Repository

Gan, Liyong; Schwingenschlö gl, Udo

2014-01-01

Two-dimensional (2D) materials often adopt a hexagonal lattice. We report on a class of 2D materials, Cu2MX4 (M = Mo, W; X = S, Se), that has a square lattice. Up to three monolayers, the systems are kinetically stable. All of them are semiconductors with band gaps from 2.03 to 2.48 eV. Specifically, the states giving rise to the valence band maximum are confined to the Cu and X atoms, while those giving rise to the conduction band minimum are confined to the M atoms, suggesting that spontaneous charge separation occurs. The semiconductive nature makes the materials promising for transistors, optoelectronics, and solar energy conversion. Moreover, the ferromagnetism on the edges of square Cu2MX4 nanoribbons opens applications in spintronics.
Bayes allocation of the sample for estimation of the mean when each stratum has a Poisson distribution

International Nuclear Information System (INIS)

Wright, T.

1983-01-01

Consider a stratified population with L strata, so that a Poisson random variable is associated with each stratum. The parameter associated with the hth stratum is theta/sub h/, h = 1, 2, ..., L. Let ω/sub h/ be the known proportion of the population in the hth stratum, h = 1, 2, ..., L. The authors want to estimate the parameter theta = summation from h = 1 to L ω/sub h/theta/sub h/. We assume that prior information is available on theta/sub h/ and that it can be expressed in terms of a gamma distribution with parameters α/sub h/ and β/sub h/, h = 1, 2, ..., L. We also assume that the prior distributions are independent. Using squared error loss function, a Bayes allocation of total sample size with a cost constraint is given. The Bayes estimate using the Bayes allocation is shown to have an adjusted mean square error which is strictly less than the adjusted mean square error of the classical estimate using the classical allocation
Lax-pair operators for squared-sum and squared-difference eigenfunctions

International Nuclear Information System (INIS)

Ichikawa, Yoshihiko; Iino, Kazuhiro.

1984-10-01

Inter-relationship between various representations of the inverse scattering transformation is established by examining eigenfunctions of Lax-pair operators of the sine-Gordon equation and the modified Korteweg-de Vries equation. In particular, it is shown explicitly that there exists Lax-pair operators for the squared-sum and squared-difference eigenfunctions of the Ablowitz-Kaup-Newell-Segur inverse scattering transformation. (author)
Total synthesis of bryostatins: the development of methodology for the atom-economic and stereoselective synthesis of the ring C subunit.

Science.gov (United States)

Trost, Barry M; Frontier, Alison J; Thiel, Oliver R; Yang, Hanbiao; Dong, Guangbin

2011-08-22

Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Symmetry breaking states of Bose-Einstein condensates in 1D double square well and optical lattice well

International Nuclear Information System (INIS)

Yuan Qingxin; Ding Guohui

2005-01-01

We investigate the phenomena of symmetry breaking and phase transition in the ground state of Bose-Einstein condensates (BECs). For BECs trapped in a double square well potential, we present symmetric and asymmetric ground states by using standing-wave expansion method. For BECs trapped in an optical lattice well potential (created by a standing laser wave, and not just an extension of the double square well potential), we reveal a phase transition by using plane-wave expansion method. At the same time we also study the ground state properties with changing the depth of potential and atomic interactions (restrict ourselves to the attractive regime)
A new method for mapping the three-dimensional atomic distribution within nanoparticles by atom probe tomography (APT).

Science.gov (United States)

Kim, Se-Ho; Kang, Phil Woong; Park, O Ok; Seol, Jae-Bok; Ahn, Jae-Pyoung; Lee, Ji Yeong; Choi, Pyuck-Pa

2018-07-01

We present a new method of preparing needle-shaped specimens for atom probe tomography from freestanding Pd and C-supported Pt nanoparticles. The method consists of two steps, namely electrophoresis of nanoparticles on a flat Cu substrate followed by electrodeposition of a Ni film acting as an embedding matrix for the nanoparticles. Atom probe specimen preparation can be subsequently carried out by means of focused-ion-beam milling. Using this approach, we have been able to perform correlative atom probe tomography and transmission electron microscopy analyses on both nanoparticle systems. Reliable mass spectra and three-dimensional atom maps could be obtained for Pd nanoparticle specimens. In contrast, atom probe samples prepared from C-supported Pt nanoparticles showed uneven field evaporation and hence artifacts in the reconstructed atom maps. Our developed method is a viable means of mapping the three-dimensional atomic distribution within nanoparticles and is expected to contribute to an improved understanding of the structure-composition-property relationships of various nanoparticle systems. Copyright © 2018 Elsevier B.V. All rights reserved.
Irrational Square Roots

Science.gov (United States)

Misiurewicz, Michal

2013-01-01

If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?
An Inverse Function Least Square Fitting Approach of the Buildup Factor for Radiation Shielding Analysis

Energy Technology Data Exchange (ETDEWEB)

Park, Chang Je [Sejong Univ., Seoul (Korea, Republic of); Alkhatee, Sari; Roh, Gyuhong; Lee, Byungchul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Dose absorption and energy absorption buildup factors are widely used in the shielding analysis. The dose rate of the medium is main concern in the dose buildup factor, however energy absorption is an important parameter in the energy buildup factors. ANSI/ANS-6.4.3-1991 standard data is widely used based on interpolation and extrapolation by means of an approximation method. Recently, Yoshida's geometric progression (GP) formulae are also popular and it is already implemented in QAD code. In the QAD code, two buildup factors are notated as DOSE for standard air exposure response and ENG for the response of the energy absorbed in the material itself. In this paper, a new least square fitting method is suggested to obtain a reliable buildup factors proposed since 1991. Total 4 datasets of air exposure buildup factors are used for evaluation including ANSI/ANS-6.4.3-1991, Taylor, Berger, and GP data. The standard deviation of the fitted data are analyzed based on the results. A new reverse least square fitting method is proposed in this study in order to reduce the fitting uncertainties. It adapts an inverse function rather than the original function by the distribution slope of dataset. Some quantitative comparisons are provided for concrete and lead in this paper, too. This study is focused on the least square fitting of existing buildup factors to be utilized in the point-kernel code for radiation shielding analysis. The inverse least square fitting method is suggested to obtain more reliable results of concave shaped dataset such as concrete. In the concrete case, the variance and residue are decreased significantly, too. However, the convex shaped case of lead can be applied to the usual least square fitting method. In the future, more datasets will be tested by using the least square fitting. And the fitted data could be implemented to the existing point-kernel codes.
Interaction of slow and highly charged ions with surfaces: formation of hollow atoms

Energy Technology Data Exchange (ETDEWEB)

Stolterfoht, N; Grether, M; Spieler, A; Niemann, D [Hahn-Meitner Institut, Berlin (Germany). Bereich Festkoerperphysik; Arnau, A

1997-03-01

The method of Auger spectroscopy was used to study the interaction of highly charged ions with Al and C surfaces. The formation of hollow Ne atoms in the first surface layers was evaluated by means of a Density Functional theory including non-linear screening effects. The time-dependent filling of the hollow atom was determined from a cascade model yielding information about the structure of the K-Auger spectra. Variation of total intensities of the L- and K-Auger peaks were interpreted by the cascade model in terms of attenuation effects on the electrons in the solid. (author)
Limits on visibility of single heavy atoms in the scanning transmission electron microscope: an experimental study

Energy Technology Data Exchange (ETDEWEB)

Wall, J.S.

1979-01-01

Theoretical calculations of the visibility of single heavy atoms on thin carbon substrates have predicted higher signal to noise ratios then experimentally observed. Six experimental measurements were performed to determine where the theory is inadequate, five to determine the absolute value of heavy atom scattering cross sections in practical units, and one to determine substrate noise in some practical units. The practical unit of measure was chosen to be the scattering power of one carbon atom as determined by an internal standard, Tobacco Mosaic Virus. Measurements were performed on the following targets on thin carbon substrates: single isolated uranium atoms; silicotungstate clusters; colloidal platinum particles; fd bacteriophage embedded in negative strain; and fd bacteriophage reacted with a known quantity of heavy atom reagent. These measurements suggest that the scattering power of one heavy atom is approximately 9 +- 4 carbon atom equivalents, instead of 15 to 24 predicted by theory. The same techniques were used to measure intensity fluctuations from area to area of a clean substrate. Substrate noise was found to be less than expected for squares of width less than 10A, but up to 2.5 times greater than expected for larger squares. These signal and noise measurements have been combined to give an empirical formula for calculating signal to noise ratios from specimen and microscope parameters.
Dancoff Correction in Square and Hexagonal Lattices

Energy Technology Data Exchange (ETDEWEB)

Carlvik, I

1966-11-15

This report presents the results of a series of calculations of Dancoff corrections for square and hexagonal rod lattices. The tables cover a wide range of volume ratios and moderator cross sections. The results were utilized for checking the approximative formula of Sauer and also the modification of Bonalumi to Sauer's formula. The modified formula calculates the Dancoff correction with an accuracy of 0.01 - 0.02 in cases of practical interest. Calculations have also been performed on square lattices with an empty gap surrounding the rods. The results demonstrate the error involved in treating this kind of geometry by means of homogenizing the gap and the moderator. The calculations were made on the Ferranti Mercury computer of AB Atomenergi before it was closed down. Since then FORTRAN routines for Dancoff corrections have been written, and a subroutine DASQHE is included in the report.
The dressed mobile atoms and ions

CERN Document Server

Amour, B; Guillot, L

2005-01-01

We consider free atoms and ions in $\\R^3$ interacting with the quantized electromagnetic field. Because of the translation invariance we consider the reduced hamiltonian associated with the total momentum. After introducing an ultraviolet cutoff we prove that the reduced hamiltonian for atoms has a ground state if the coupling constant and the total momentum are sufficiently small. In the case of ions an extra infrared regularization is needed. We also consider the case of the hydrogen atom in a constant magnetic field. Finally we determine the absolutely continuous spectrum of the reduced hamiltonian. \\end{abstract}
Atomic and molecular science with synchrotron radiation

International Nuclear Information System (INIS)

1989-01-01

This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs
Quantitative determination of absorbed hydrogen in oxidised zircaloy by means of neutron radiography

International Nuclear Information System (INIS)

Grosse, M.; Lehmann, E.; Vontobel, P.; Steinbrueck, M.

2006-01-01

Hydrogen absorbed in steam-oxidised zircaloy can be determined quantitatively by means of neutron radiography. Correlation parameters between the total cross section and hydrogen content as well as oxide layer thickness were determined quantitatively. At H/Zr atomic ratios lower than 1.0, linear correlations between the hydrogen content and total cross section exist. The total cross section of Zr is lower and the effect of the hydrogen is higher in radiography measurements with a cold neutron spectrum than with a thermal spectrum. A Be filter reduces the effects of lower wavelength and epithermal neutrons and extends the linear correlations to higher H/Zr atomic ratios. Due to the better possibilities of background corrections, the neutron image should be detected by a CCD camera for a proper quantitative analysis with a medium spatial resolution of about 0.1 mm. A higher spatial resolution, but larger uncertainties in the quantitative hydrogen determination are achieved by measurements with imaging plates. The effect of oxygen layers on the total cross section is much smaller than the effect of hydrogen. The total cross section measured depends linearly on the oxide layer thickness
Aspherical-atom modeling of coordination compounds by single-crystal X-ray diffraction allows the correct metal atom to be identified.

Science.gov (United States)

Dittrich, Birger; Wandtke, Claudia M; Meents, Alke; Pröpper, Kevin; Mondal, Kartik Chandra; Samuel, Prinson P; Amin Sk, Nurul; Singh, Amit Pratap; Roesky, Herbert W; Sidhu, Navdeep

2015-02-02

Single-crystal X-ray diffraction (XRD) is often considered the gold standard in analytical chemistry, as it allows element identification as well as determination of atom connectivity and the solid-state structure of completely unknown samples. Element assignment is based on the number of electrons of an atom, so that a distinction of neighboring heavier elements in the periodic table by XRD is often difficult. A computationally efficient procedure for aspherical-atom least-squares refinement of conventional diffraction data of organometallic compounds is proposed. The iterative procedure is conceptually similar to Hirshfeld-atom refinement (Acta Crystallogr. Sect. A- 2008, 64, 383-393; IUCrJ. 2014, 1,61-79), but it relies on tabulated invariom scattering factors (Acta Crystallogr. Sect. B- 2013, 69, 91-104) and the Hansen/Coppens multipole model; disordered structures can be handled as well. Five linear-coordinate 3d metal complexes, for which the wrong element is found if standard independent-atom model scattering factors are relied upon, are studied, and it is shown that only aspherical-atom scattering factors allow a reliable assignment. The influence of anomalous dispersion in identifying the correct element is investigated and discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Growth kinetics of borided layers: Artificial neural network and least square approaches

Science.gov (United States)

Campos, I.; Islas, M.; Ramírez, G.; VillaVelázquez, C.; Mota, C.

2007-05-01

The present study evaluates the growth kinetics of the boride layer Fe 2B in AISI 1045 steel, by means of neural networks and the least square techniques. The Fe 2B phase was formed at the material surface using the paste boriding process. The surface boron potential was modified considering different boron paste thicknesses, with exposure times of 2, 4 and 6 h, and treatment temperatures of 1193, 1223 and 1273 K. The neural network and the least square models were set by the layer thickness of Fe 2B phase, and assuming that the growth of the boride layer follows a parabolic law. The reliability of the techniques used is compared with a set of experiments at a temperature of 1223 K with 5 h of treatment time and boron potentials of 2, 3, 4 and 5 mm. The results of the Fe 2B layer thicknesses show a mean error of 5.31% for the neural network and 3.42% for the least square method.
Atomic vibration amplitudes in fcc and hcp 4He through x-ray diffraction measurements

International Nuclear Information System (INIS)

Venkataraman, C.T.; Simmons, R.O.

2003-01-01

Atomic vibration amplitudes in dense fcc and hcp 4 He crystals have been measured using synchrotron x rays from the dependence of integrated Bragg intensities up to wave vectors of 91 nm -1 . Observed raw Bragg x-ray integrated intensities cover an extraordinary range, greater than 10 5 , due to the combined effect of the Debye-Waller factor and electronic form factor. From analysis of these intensities mean-square atomic vibration amplitudes Q 2 > and Lindemann ratios are determined. Path-integral Monte Carlo (PIMC) computations of Draeger and Ceperley, extrapolated to the thermodynamic limit, provide excellent agreement with these experimental results. For both present measurements and the PIMC results, one finds both a predominantly Gaussian distribution in Q 2 > and an extraordinarily large Lindemann ratio. In contrast, these directly measured x-ray values are significantly larger than published values inferred from Born-von Karman fitting to phonon dispersion measured by neutron scattering. Mildly anharmonic neon, which is fairly well described by self-consistent phonon theories, is contrasted with present results on fcc 4 He at corresponding densities
TRACE ANALYSIS BY LASER-EXCITED ATOMIC FLUORESCENCE WITH ATOMIZATION IN A PULSED PLASMA

OpenAIRE

Lunyov , O.; Oshemkov , S.; Petrov , A.

1991-01-01

The possibilities of plasma atomization for laser fluorescence trace analysis are discussed. Pulsed hot hollow cathode discharge was used for analysis of solutions and powdered samples. The high voltage spark and laser-induced breakdown (laser spark) were used as atomizers of metal-containing atmospheric aerosols. Detection limits were improved by means of temporal background selection.
A total safety management model

International Nuclear Information System (INIS)

Obadia, I.J.; Vidal, M.C.R.; Melo, P.F.F.F.

2002-01-01

In nuclear organizations, quality and safety are inextricably linked. Therefore, the search for excellence means reaching excellence in nuclear safety. The International Atomic Energy Agency, IAEA, developed, after the Chernobyl accident, the organizational approach for improving nuclear safety based on the safety culture, which requires a framework necessary to provide modifications in personnel attitudes and behaviors in situations related to safety. This work presents a Total Safety Management Model, based on the Model of Excellence of the Brazilian Quality Award and on the safety culture approach, which represents an alternative to this framework. The Model is currently under validation at the Nuclear Engineering Institute, in Rio de Janeiro, Brazil, and the results of its initial safety culture self assessment are also presented and discussed. (author)
Weighted conditional least-squares estimation

International Nuclear Information System (INIS)

Booth, J.G.

1987-01-01

A two-stage estimation procedure is proposed that generalizes the concept of conditional least squares. The method is instead based upon the minimization of a weighted sum of squares, where the weights are inverses of estimated conditional variance terms. Some general conditions are given under which the estimators are consistent and jointly asymptotically normal. More specific details are given for ergodic Markov processes with stationary transition probabilities. A comparison is made with the ordinary conditional least-squares estimators for two simple branching processes with immigration. The relationship between weighted conditional least squares and other, more well-known, estimators is also investigated. In particular, it is shown that in many cases estimated generalized least-squares estimators can be obtained using the weighted conditional least-squares approach. Applications to stochastic compartmental models, and linear models with nested error structures are considered

[Prediction of total nitrogen and alkali hydrolysable nitrogen content in loess using hyperspectral data based on correlation analysis and partial least squares regression].

Science.gov (United States)

Liu, Xiu-ying; Wang, Li; Chang, Qing-rui; Wang, Xiao-xing; Shang, Yan

2015-07-01

Wuqi County of Shaanxi Province, where the vegetation recovering measures have been carried out for years, was taken as the study area. A total of 100 loess samples from 24 different profiles were collected. Total nitrogen (TN) and alkali hydrolysable nitrogen (AHN) contents of the soil samples were analyzed, and the soil samples were scanned in the visible/near-infrared (VNIR) region of 350-2500 nm in the laboratory. The calibration models were developed between TN and AHN contents and VNIR values based on correlation analysis (CA) and partial least squares regression (PLS). Independent samples validated the calibration models. The results indicated that the optimum model for predicting TN of loess was established by using first derivative of reflectance. The best model for predicting AHN of loess was established by using normal derivative spectra. The optimum TN model could effectively predict TN in loess from 0 to 40 cm, but the optimum AHN model could only roughly predict AHN at the same depth. This study provided a good method for rapidly predicting TN of loess where vegetation recovering measures have been adopted, but prediction of AHN needs to be further studied.
Decision-Directed Recursive Least Squares MIMO Channels Tracking

Directory of Open Access Journals (Sweden)

Karami Ebrahim

2006-01-01

Full Text Available A new approach for joint data estimation and channel tracking for multiple-input multiple-output (MIMO channels is proposed based on the decision-directed recursive least squares (DD-RLS algorithm. RLS algorithm is commonly used for equalization and its application in channel estimation is a novel idea. In this paper, after defining the weighted least squares cost function it is minimized and eventually the RLS MIMO channel estimation algorithm is derived. The proposed algorithm combined with the decision-directed algorithm (DDA is then extended for the blind mode operation. From the computational complexity point of view being versus the number of transmitter and receiver antennas, the proposed algorithm is very efficient. Through various simulations, the mean square error (MSE of the tracking of the proposed algorithm for different joint detection algorithms is compared with Kalman filtering approach which is one of the most well-known channel tracking algorithms. It is shown that the performance of the proposed algorithm is very close to Kalman estimator and that in the blind mode operation it presents a better performance with much lower complexity irrespective of the need to know the channel model.
Bounded Perturbation Regularization for Linear Least Squares Estimation

KAUST Repository

Ballal, Tarig

2017-10-18

This paper addresses the problem of selecting the regularization parameter for linear least-squares estimation. We propose a new technique called bounded perturbation regularization (BPR). In the proposed BPR method, a perturbation with a bounded norm is allowed into the linear transformation matrix to improve the singular-value structure. Following this, the problem is formulated as a min-max optimization problem. Next, the min-max problem is converted to an equivalent minimization problem to estimate the unknown vector quantity. The solution of the minimization problem is shown to converge to that of the ℓ2 -regularized least squares problem, with the unknown regularizer related to the norm bound of the introduced perturbation through a nonlinear constraint. A procedure is proposed that combines the constraint equation with the mean squared error (MSE) criterion to develop an approximately optimal regularization parameter selection algorithm. Both direct and indirect applications of the proposed method are considered. Comparisons with different Tikhonov regularization parameter selection methods, as well as with other relevant methods, are carried out. Numerical results demonstrate that the proposed method provides significant improvement over state-of-the-art methods.
Cold experiment of slag centrifugal granulation by rotary atomizer: Effect of atomizer configuration

International Nuclear Information System (INIS)

Wu, Jun-Jun; Wang, Hong; Zhu, Xun; Liao, Qiang; Li, Kai

2017-01-01

Centrifugal granulation has recently been employed to produce small blast furnace slag particles, so as to recover the waste heat from the high-temperature molten blast furnace slag. An appropriate atomizer enables centrifugal granulation to become a better cost-effective process for particle production. Thus, increasing emphasis has been placed on influence of atomizer configuration on granulation. In present study, three groups of atomizers were specially designed and the granulation performance of each atomizer was experimentally tested during cold experiments. The influences of atomizer configuration on granulation modes and droplet characteristics were investigated visually. Two modified correlations were proposed to predict the granulating droplet size by means of data fitting. The results indicated that the rotary cup atomizers can inhibit the film formation in contrast to rotary disc atomizer. Moreover, atomizers with outer angle of 90° was capable of producing smaller droplets. The revised correlation as well as the newly-developed correlation including the influence of atomizer configurations, presented in good agreement with the experiment data. In addition, an analysis on atomizer design was conducted to provide a good insight for industrialization. It was recommended to adopt cup-like atomizer in granulation for its ability to produce fine particles with smaller atomizer size.
Discrete least squares polynomial approximation with random evaluations − application to parametric and stochastic elliptic PDEs

KAUST Repository

Chkifa, Abdellah

2015-04-08

Motivated by the numerical treatment of parametric and stochastic PDEs, we analyze the least-squares method for polynomial approximation of multivariate functions based on random sampling according to a given probability measure. Recent work has shown that in the univariate case, the least-squares method is quasi-optimal in expectation in [A. Cohen, M A. Davenport and D. Leviatan. Found. Comput. Math. 13 (2013) 819–834] and in probability in [G. Migliorati, F. Nobile, E. von Schwerin, R. Tempone, Found. Comput. Math. 14 (2014) 419–456], under suitable conditions that relate the number of samples with respect to the dimension of the polynomial space. Here “quasi-optimal” means that the accuracy of the least-squares approximation is comparable with that of the best approximation in the given polynomial space. In this paper, we discuss the quasi-optimality of the polynomial least-squares method in arbitrary dimension. Our analysis applies to any arbitrary multivariate polynomial space (including tensor product, total degree or hyperbolic crosses), under the minimal requirement that its associated index set is downward closed. The optimality criterion only involves the relation between the number of samples and the dimension of the polynomial space, independently of the anisotropic shape and of the number of variables. We extend our results to the approximation of Hilbert space-valued functions in order to apply them to the approximation of parametric and stochastic elliptic PDEs. As a particular case, we discuss “inclusion type” elliptic PDE models, and derive an exponential convergence estimate for the least-squares method. Numerical results confirm our estimate, yet pointing out a gap between the condition necessary to achieve optimality in the theory, and the condition that in practice yields the optimal convergence rate.
Evidence for πK-atoms with DIRAC

International Nuclear Information System (INIS)

Adeva, B.; Afanasyev, L.; Allkofer, Y.; Amsler, C.; Anania, A.; Benelli, A.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Chliapnikov, P.; Ciocarlan, C.; Constantinescu, S.; Curceanu, C.; Detraz, C.; Dreossi, D.; Drijard, D.; Dudarev, A.; Duma, M.; Dumitriu, D.

2009-01-01

We present evidence for the first observation of electromagnetically bound π ± K ± -pairs (πK-atoms) with the DIRAC experiment at the CERN-PS. The πK-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the π ± and K ± -mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173±54πK-atoms. The mean life of πK-atoms is related to the s-wave πK-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level.
Square-root measurement for pure states

International Nuclear Information System (INIS)

Huang Siendong

2005-01-01

Square-root measurement is a very useful suboptimal measurement in many applications. It was shown that the square-root measurement minimizes the squared error for pure states. In this paper, the least squared error problem is reformulated and a new proof is provided. It is found that the least squared error depends only on the average density operator of the input states. The properties of the least squared error are then discussed, and it is shown that if the input pure states are uniformly distributed, the average probability of error has an upper bound depending on the least squared error, the rank of the average density operator, and the number of the input states. The aforementioned properties help explain why the square-root measurement can be effective in decoding processes
Experimental evidence for πK-atoms

International Nuclear Information System (INIS)

Amsler, C.

2009-01-01

We present evidence for the first observation of electromagnetically bound pion-kaon pairs (πK- atoms) with the DIRAC-II experiment at the CERN-PS. The mean life of πK-atoms is related to the s-wave πK-scattering lengths, a measurement of which is relevant to low energy QCD, in particular chiral perturbation theories including the s-quarks. The atoms are produced by a 24 GeV/c proton beam in a thin Pt-target and the dissociated pions and kaons analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173± 54 πK-atoms. From these first data we derive a lower limit for the mean life of 0.8 fs at the 90 % confidence level. (author)
Symmetry Breaking Ground States of Bose-Einstein Condensates in 1D Double Square Well and Optical Lattice Well

International Nuclear Information System (INIS)

Yuan Qingxin; Ding Guohui

2005-01-01

We investigate the phenomena of symmetry breaking and phase transition in the ground state of Bose-Einstein condensates (BECs) trapped in a double square well and in an optical lattice well, respectively. By using standing-wave expansion method, we present symmetric and asymmetric ground state solutions of nonlinear Schroedinger equation (NLSE) with a symmetric double square well potential for attractive nonlinearity. In particular, we study the ground state wave function's properties by changing the depth of potential and atomic interactions (here we restrict ourselves to the attractive regime). By using the Fourier grid Hamiltonian method, we also reveal a phase transition of BECs trapped in one-dimensional optical lattice potential.
Regularities in positronium formation for atoms and molecules

International Nuclear Information System (INIS)

Machacek, J R; Buckman, S J; Sullivan, J P; Blanco, F; Garcia, G

2016-01-01

In an effort to aid the modelling of positron and positronium (Ps) transport in biological media we have compiled recent experimental results for the total Ps formation in positron scattering from atoms and molecules. A simple function was found to adequately describe the total Ps formation cross section for both atoms and molecules. The parameters of this function describe the magnitude and shape of the Ps formation cross section and are compared to physical characteristics of the target atoms and molecules. A general trend in the magnitude of the total Ps formation cross section is observed as a function of the target atom/molecule dipole polarisability. The functional form may enable quick estimation of the Ps cross section for molecules for which experimental measurements or theoretical estimates do not exist. (paper)
RVB signatures in the spin dynamics of the square-lattice Heisenberg antiferromagnet

Science.gov (United States)

Ghioldi, E. A.; Gonzalez, M. G.; Manuel, L. O.; Trumper, A. E.

2016-03-01

We investigate the spin dynamics of the square-lattice spin-\\frac{1}{2} Heisenberg antiferromagnet by means of an improved mean-field Schwinger boson calculation. By identifying both, the long-range Néel and the RVB-like components of the ground state, we propose an educated guess for the mean-field magnetic excitation consisting on a linear combination of local and bond spin flips to compute the dynamical structure factor. Our main result is that when this magnetic excitation is optimized in such a way that the corresponding sum rule is fulfilled, we recover the low- and high-energy spectral weight features of the experimental spectrum. In particular, the anomalous spectral weight depletion at (π,0) found in recent inelastic neutron scattering experiments can be attributed to the interference of the triplet bond excitations of the RVB component of the ground state. We conclude that the Schwinger boson theory seems to be a good candidate to adequately interpret the dynamic properties of the square-lattice Heisenberg antiferromagnet.
Depth of origin of atoms sputtered from crystalline targets

International Nuclear Information System (INIS)

Shapiro, M.H.; Trovato, E.; Tombrello, T.A.

2001-01-01

Recently, V.I. Shulga and W. Eckstein (Nucl. Instr. and Meth. B 145 (1998) 492) investigated the depth of origin of atoms sputtered from random elemental targets using the Monte Carlo code TRIM.SP and the lattice code OKSANA. They found that the mean depth of origin is proportional to N -0.86 , where N is the atomic density; and that the most probable escape depth is ∼λ 0 /2, where λ 0 is the mean atomic distance. Since earlier molecular dynamics simulations with small crystalline elemental targets typically produced a most probable escape depth of zero (i.e., most sputtered atoms came from the topmost layer of the target), we have carried out new molecular dynamics simulations of sputtered atom escape depths with much larger crystalline targets. Our new results, which include the bcc targets Cs, Rb and W, as well as the fcc targets Cu and Au predict that the majority of sputtered atoms come from the first atomic layer for the bcc(1 0 0), bcc(1 1 1), fcc(1 0 0) and fcc(1 1 1) targets studied. For the high-atomic density targets Cu, Au and W, the mean depth of origin of sputtered atoms typically is less than 0.25λ 0 . For the low-atomic density targets Cs and Rb, the mean depth of origin of sputtered atoms is considerably larger, and depends strongly on the crystal orientation. We show that the discrepancy between the single-crystal and amorphous target depth of origin values can be resolved by applying a simple correction to the single-crystal results
Atomic force microscopy study of TiO2 sol-gel films thermally treated under NH3 atmosphere

International Nuclear Information System (INIS)

Trapalis, C.; Todorova, N.; Anastasescu, M.; Anastasescu, C.; Stoica, M.; Gartner, M.; Zaharescu, M.; Stoica, T.

2009-01-01

Multilayered TiO 2 films were obtained by sol-gel and dipping deposition on quartz substrate followed by thermal treatment under NH 3 atmosphere. In an attempt to understand the close relationship between microstructural characteristics and the synthesis parameters, a systematic research of the structure and the morphology of NH 3 modified TiO 2 sol-gel films by XRD and Atomic Force Microscopy is reported. The surface morphology has been evaluated in terms of grains size, fractal dimension and surface roughness. For each surface, it was found a self-similar behavior (with mean fractal dimension in the range of 2.67-3.00) related to an optimum morphology favorable to maintain a nano-size distribution of the grains. The root mean square (RMS) roughness of the samples was found to be in the range of 0.72-6.02 nm.
Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO{sub 3}){sub n} films by means of metalorganic aerosol deposition

Energy Technology Data Exchange (ETDEWEB)

Jungbauer, M.; Hühn, S.; Moshnyaga, V. [Erstes Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G. [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

2014-12-22

We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO{sub 3}){sub n} (n = ∞, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO{sub 3}(001) substrates by means of a sequential deposition of Sr-O/Ti-O{sub 2} atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO{sub 3}){sub 4} block at the level of 2.4%. This identifies the SrTiO{sub 3} substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy.
Evaluation of total and partial structure factors, self-diffusion coefficients, and compressibilities of the cadmium-gallium melt

International Nuclear Information System (INIS)

Gopala Rao, R.V.; Das, R.

1988-01-01

The three partial structure factors S/sub 11/(K), S/sub 22/(K), and S/sub 12/(K) defined by Ashcroft and Langreth are computed with a square-well potential as a perturbation over a hard-sphere potential for different atomic fractions or concentrations of cadmium for Cd-Ga melt at 296 0 C. Also, the number-number, concentration-concentration, and the cross-term number-concentration structure factors due to Bhatia-Thornton have been calculated for the seven concentrations of Cd-Ga melt at that temperature. From these partial structure factors total structure factors are computed and are compared with the experimental results. The total structure factors so computed are found to be in excellent agreement with the measured values except in the long-wavelength limit of S(0). Using the partial structure factors in the long-wavelength limit the isothermal compressibilities have been calculated. From these partial structure factors and by using the linear-trajectory approximation of Helfand, the self-diffusion coefficients D/sub i/'s have also been calculated for various atomic fractions of Cd for Cd-Ga alloy at 296 0 C. From these D/sub i/'s, an estimate of the mutual diffusion coefficients has been made to a good approximation
Zero-Forcing and Minimum Mean-Square Error Multiuser Detection in Generalized Multicarrier DS-CDMA Systems for Cognitive Radio

Directory of Open Access Journals (Sweden)

Lie-Liang Yang

2008-01-01

Full Text Available In wireless communications, multicarrier direct-sequence code-division multiple access (MC DS-CDMA constitutes one of the highly flexible multiple access schemes. MC DS-CDMA employs a high number of degrees-of-freedom, which are beneficial to design and reconfiguration for communications in dynamic communications environments, such as in the cognitive radios. In this contribution, we consider the multiuser detection (MUD in MC DS-CDMA, which motivates lowcomplexity, high flexibility, and robustness so that the MUD schemes are suitable for deployment in dynamic communications environments. Specifically, a range of low-complexity MUDs are derived based on the zero-forcing (ZF, minimum mean-square error (MMSE, and interference cancellation (IC principles. The bit-error rate (BER performance of the MC DS-CDMA aided by the proposed MUDs is investigated by simulation approaches. Our study shows that, in addition to the advantages provided by a general ZF, MMSE, or IC-assisted MUD, the proposed MUD schemes can be implemented using modular structures, where most modules are independent of each other. Due to the independent modular structure, in the proposed MUDs one module may be reconfigured without yielding impact on the others. Therefore, the MC DS-CDMA, in conjunction with the proposed MUDs, constitutes one of the promising multiple access schemes for communications in the dynamic communications environments such as in the cognitive radios.
Zero-Forcing and Minimum Mean-Square Error Multiuser Detection in Generalized Multicarrier DS-CDMA Systems for Cognitive Radio

Directory of Open Access Journals (Sweden)

Wang Li-Chun

2008-01-01

Full Text Available Abstract In wireless communications, multicarrier direct-sequence code-division multiple access (MC DS-CDMA constitutes one of the highly flexible multiple access schemes. MC DS-CDMA employs a high number of degrees-of-freedom, which are beneficial to design and reconfiguration for communications in dynamic communications environments, such as in the cognitive radios. In this contribution, we consider the multiuser detection (MUD in MC DS-CDMA, which motivates lowcomplexity, high flexibility, and robustness so that the MUD schemes are suitable for deployment in dynamic communications environments. Specifically, a range of low-complexity MUDs are derived based on the zero-forcing (ZF, minimum mean-square error (MMSE, and interference cancellation (IC principles. The bit-error rate (BER performance of the MC DS-CDMA aided by the proposed MUDs is investigated by simulation approaches. Our study shows that, in addition to the advantages provided by a general ZF, MMSE, or IC-assisted MUD, the proposed MUD schemes can be implemented using modular structures, where most modules are independent of each other. Due to the independent modular structure, in the proposed MUDs one module may be reconfigured without yielding impact on the others. Therefore, the MC DS-CDMA, in conjunction with the proposed MUDs, constitutes one of the promising multiple access schemes for communications in the dynamic communications environments such as in the cognitive radios.
Formulating analytic expressions for atomic collision cross sections

International Nuclear Information System (INIS)

Tabata, Tatsuo; Kubo, Hirotaka; Sataka, Masao

2003-08-01

Methods to formulate analytic expression for atomic collision cross sections as a function of projectile energy are described on the basis of the experiences of the data compilation work for more than 20 years. Topics considered are the choice of appropriate functional forms for the expressions and optimization of adjustable parameters. To make extrapolation possible, functions to be used should have the form with reasonable asymptotic behavior. In this respect, modified Green-McNeal formulas have been found useful for various atomic collision cross sections. For ionization processes, a modified Lotz formula has often given a good fit. The ALESQ code for least-squares fits has been convenient to optimize adjustable parameters in analytic expressions. (author)
The Versatile Magic Square.

Science.gov (United States)

Watson, Gale A.

2003-01-01

Demonstrates the transformations that are possible to construct a variety of magic squares, including modifications to challenge students from elementary grades through algebra. Presents an example of using magic squares with students who have special needs. (YDS)
Orbital effect of the magnetic field in dynamical mean-field theory

Science.gov (United States)

Acheche, S.; Arsenault, L.-F.; Tremblay, A.-M. S.

2017-12-01

The availability of large magnetic fields at international facilities and of simulated magnetic fields that can reach the flux-quantum-per-unit-area level in cold atoms calls for systematic studies of orbital effects of the magnetic field on the self-energy of interacting systems. Here we demonstrate theoretically that orbital effects of magnetic fields can be treated within single-site dynamical mean-field theory with a translationally invariant quantum impurity problem. As an example, we study the one-band Hubbard model on the square lattice using iterated perturbation theory as an impurity solver. We recover the expected quantum oscillations in the scattering rate, and we show that the magnetic fields allow the interaction-induced effective mass to be measured through the single-particle density of states accessible in tunneling experiments. The orbital effect of magnetic fields on scattering becomes particularly important in the Hofstadter butterfly regime.

Hydrogen atom moving across a magnetic field

International Nuclear Information System (INIS)

Lozovik, Yu.E.; Volkov, S.Yu.

2004-01-01

A hydrogen atom moving across a magnetic field is considered in a wide region of magnitudes of magnetic field and atom momentum. We solve the Schroedinger equation of the system numerically using an imaginary time method and find wave functions of the lowest states of atom. We calculate the energy and the mean electron-nucleus separation as a function of atom momentum and magnetic field. All the results obtained could be summarized as a phase diagram on the 'atom-momentum - magnetic-field' plane. There are transformations of wave-function structure at critical values of atom momentum and magnetic field that result in a specific behavior of dependencies of energy and mean interparticle separation on the atom momentum P. We discuss a transition from the Zeeman regime to the high magnetic field regime. A qualitative analysis of the complicated behavior of wave functions vs P based on the effective potential examination is given. We analyze a sharp transition at the critical momentum from a Coulomb-type state polarized due to atom motion to a strongly decentered (Landau-type) state at low magnetic fields. A crossover occurring at intermediate magnetic fields is also studied
Polarizational radiation or 'atomic' bremsstrahlung

International Nuclear Information System (INIS)

Ya Amusia, M.

1992-01-01

It is demonstrated that a new kind of continuum spectrum radiation exists, where the mechanism of formation is quite different from that of ordinary bremsstrahlung. The latter originates due to slowing down of the charged projectile in the target field, while the former, called polarization radiation or 'atomic' bremsstrahlung, is a result of radiation either of the target or the projectile particles dipolarly polarized during the collision process. Not only general formulae, but also results of concrete calculations are presented. These demonstrate, that for electron-atom collisions the atomic contribution to the total bremsstrahlung spectrum becomes dominant for photon energies near and above the atomic ionization potential. As to atom-atom or ion-atom collisions, the bremsstrahlung spectrum is completely determined by the atomic contribution. The specific features of the case when the incoming particles are relativistic are discussed at length. A number of examples of colliding pairs are considered, for which the atomic bremsstrahlung process is quite essential: A bare nucleus and an atom, pair of atoms, at least one of which is excited, electron, or atom interacting with a molecule. The same mechanism is essential also in formation of radiation in nuclear and elementary particle collisions. (orig.)
Outcome analysis after helmet therapy using 3D photogrammetry in patients with deformational plagiocephaly: the role of root mean square.

Science.gov (United States)

Moghaddam, Mahsa Bidgoli; Brown, Trevor M; Clausen, April; DaSilva, Trevor; Ho, Emily; Forrest, Christopher R

2014-02-01

Deformational plagiocephaly (DP) is a multifactorial non-synostotic cranial deformity with a reported incidence as high as 1 in 7 infants in North America. Treatment options have focused on non-operative interventions including head repositioning and the use of an orthotic helmet device. Previous studies have used linear and two dimensional outcome measures to assess changes in cranial symmetry after helmet therapy. Our objective was to demonstrate improvement in head shape after treatment with a cranial molding helmet by using Root Mean Square (RMS), a measure unique to 3D photogrammetry, which takes into account both changes in volume and shape over time. Three dimensional photographs were obtained before and after molding helmet treatment in 40 infants (4-10 months old) with deformational plagiocephaly. Anatomical reference planes and measurements were recorded using the 3dMD Vultus(®) analysis software. RMS was used to quantify symmetry by superimposing left and right quadrants and calculating the mean value of aggregate distances between surfaces. Over 95% of the patients demonstrated an improvement in symmetry with helmet therapy. Furthermore, when the sample of infants was divided into two treatment subgroups, a statistically significant correlation was found between the age at the beginning of treatment and the change in the RMS value. When helmet therapy was started before 7 months of age a greater improvement in symmetry was seen. This work represents application of the technique of RMS analysis to demonstrate the efficacy of treatment of deformational plagiocephaly with a cranial molding helmet. Copyright © 2014. Published by Elsevier Ltd.
SUPPLEMENTARY COMPARISON: EUROMET.L-S10 Comparison of squareness measurements

Science.gov (United States)

Mokros, Jiri

2005-01-01

from the weighted mean of data from participating laboratories, while some of them were excluded on the basis of statistical evaluation. Graphical interpretations of all deviations are contained in the Final Report. In order to compare the individual deviations mutually (25 profiles for the granite square and 44 profiles for the cylinder), graphical illustrations of 'standard deviations' and both extreme values (max. and min.) of deviations were created. This regional supplementary comparison has provided independent information about the metrological properties of the measuring equipment and method used by the participating NMIs. The Final Report does not contain the En values. Participants could not estimate some contributions in the uncertainty budget on the basis of previous comparisons, since no comparison of this kind had ever been organized. Therefore the En value cannot reflect the actual state of the given NMI. Instead of En, an analysis has been performed by means of the Grubbs test according to ISO 5725-2. This comparison provided information about the state of provision of metrological services in the field of big squares measurement. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EUROMET, according to the provisions of the Mutual Recognition Arrangement (MRA).
An inexpensive optical sensor system for monitoring total suspended solids in water

International Nuclear Information System (INIS)

Sami Gumaan Daraigan; Mohd Zubir Matjafri; Khiruddin Abdullah; Azlan Abdul Aziz; Abdul Aziz Tajuddin; Mohd Firdaus Othman

2005-01-01

The objectives of this work are to design and develop an optical transsmissometer sensor for measuring total suspended solids TSS concentrations in water samples. The proposed optical sensor has the advantages of being relatively inexpensive, and easy to make and operate. An optical algorithm has been developed and used for the measurement of total suspended solids concentrations. The developed optical sensor components include light emitting diodes LEDs that are used for measuring transmitted light. The concentrations of total suspended solids TSS are determined from transmitted light through the water samples. The transmitted light is measured in terms of the output voltage of the photodetector of the sensor system. The readings are measured using a digital multimeter. The results indicate that the level of the photocurrent is linearly proportional to the total suspended solids concentration. The proposed algorithm produces a high correlation coefficient and low root mean square error. (Author)
Electric field imaging of single atoms

Science.gov (United States)

Shibata, Naoya; Seki, Takehito; Sánchez-Santolino, Gabriel; Findlay, Scott D.; Kohno, Yuji; Matsumoto, Takao; Ishikawa, Ryo; Ikuhara, Yuichi

2017-01-01

In scanning transmission electron microscopy (STEM), single atoms can be imaged by detecting electrons scattered through high angles using post-specimen, annular-type detectors. Recently, it has been shown that the atomic-scale electric field of both the positive atomic nuclei and the surrounding negative electrons within crystalline materials can be probed by atomic-resolution differential phase contrast STEM. Here we demonstrate the real-space imaging of the (projected) atomic electric field distribution inside single Au atoms, using sub-Å spatial resolution STEM combined with a high-speed segmented detector. We directly visualize that the electric field distribution (blurred by the sub-Å size electron probe) drastically changes within the single Au atom in a shape that relates to the spatial variation of total charge density within the atom. Atomic-resolution electric field mapping with single-atom sensitivity enables us to examine their detailed internal and boundary structures. PMID:28555629
Statistical observation on autopsy cases of malignancy at the Japanese Red Cross, Nagasaki Atomic Bomb Hospital

Energy Technology Data Exchange (ETDEWEB)

Takahara, O; Toyoda, S; Tsuno, S; Mukai, H; Uemura, S [Nagasaki Atomic Bomb Hospital (Japan)

1976-09-01

Statistical observation was made as to autopsy cases of atomic-bomb survivors in Nagasaki. The total of autopsy cases at the Japanese Red Cross, Nagasaki Atomic Bomb Hospital from the opening of the hospital, 1968, to December in 1975 was 1,486 cases (autopsy rate, 65.1%) in which 880 cases of atomic bomb survivors (autopsy rate, 68.0%) were contained. Cases of malignancy totaled 829 and 528 cases of those were atomic bomb survivors. Cases of malignancy were divided into three groups, that is, group exposured to atomic bomb at place within 2 km from the explosion place, group exposured at place from more than 2 km or entering after explosion into the city, and not-exposured group. Relationship between main malignancies and exposure was discussed, and the following results were obtained. 1) Obvious relationship was found to exist between exposure and acute and chronic medullary leukemia. 2) Malignant lymphoma was scarcely correlated with exposure, but its occurrence rate was higher than the mean rate in Japan in reflection the region where this disease occurs much geographically. 3) Relationship between exposure and stomach cancer, lung cancer, cancer of the large intestine, and double cancer was not found obviously, but occurrence rate of hepatic cancer was higher than the mean rate in Japan in three groups. The reason was supposed to be geographical factor. 4) Cases of thyroid gland cancer were a small number in female of the group exposured within 2 km, and cases of prostate cancer were a small number in the group within 2 km, but their occurrence rate was high specifically.
Statistical observation on autopsy cases of malignancy at the Japanese Red Cross, Nagasaki Atomic Bomb Hospital

International Nuclear Information System (INIS)

Takahara, Osamu; Toyoda, Shigeki; Tsuno, Sumio; Mukai, Hideaki; Uemura, Seiji

1976-01-01

Statistical observation was made as to autopsy cases of atomic-bomb survivors in Nagasaki. The total of autopsy cases at the Japanese Red Cross, Nagasaki Atomic Bomb Hospital from the opening of the hospital, 1968, to December in 1975 was 1,486 cases (autopsy rate, 65.1%) in which 880 cases of atomic bomb survivors (autopsy rate, 68.0%) were contained. Cases of malignancy totaled 829 and 528 cases of those were atomic bomb survivors. Cases of malignancy were divided into three groups, that is, group exposured to atomic bomb at place within 2 km from the explosion place, group exposured at place from more than 2 km or entering after explosion into the city, and not-exposured group. Relationship between main malignancies and exposure was discussed, and the following results were obtained. 1) Obvious relationship was found to exist between exposure and acute and chronic medullary leukemia. 2) Malignant lymphoma was scarecely correlated with exposure, but its occurrence rate was higher than the mean rate in Japan in reflection the region where this disease occurs much geographically. 3) Relationship between exposure and stomach cancer, lung cancer, cancer of the large intestine, and double cancer was not found obviously, but occurrence rate of hepatic cancer was higher than the mean rate in Japan in three groups. The reason was supposed to be geographical factor. 4) Cases of thyroid gland cancer were a small number in female of the group exposured within 2 km, and cases of prostate cancer were a small number in the group within 2 km, but their occurrence rate was high specifically. (Tsunoda, M.)
Quantum dynamics of relativistic bosons through nonminimal vector square potentials

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Luiz P. de, E-mail: oliveira.phys@gmail.com

2016-09-15

The dynamics of relativistic bosons (scalar and vectorial) through nonminimal vector square (well and barrier) potentials is studied in the Duffin–Kemmer–Petiau (DKP) formalism. We show that the problem can be mapped in effective Schrödinger equations for a component of the DKP spinor. An oscillatory transmission coefficient is found and there is total reflection. Additionally, the energy spectrum of bound states is obtained and reveals the Schiff–Snyder–Weinberg effect, for specific conditions the potential lodges bound states of particles and antiparticles. - Highlights: • DKP bosons in a nonminimal vector square potential are studied. • Spin zero and spin one bosons have the same results. • The Schiff–Snyder–Weinberg effect is observed.
Applications of square-related theorems

Science.gov (United States)

Srinivasan, V. K.

2014-04-01

The square centre of a given square is the point of intersection of its two diagonals. When two squares of different side lengths share the same square centre, there are in general four diagonals that go through the same square centre. The Two Squares Theorem developed in this paper summarizes some nice theoretical conclusions that can be obtained when two squares of different side lengths share the same square centre. These results provide the theoretical basis for two of the constructions given in the book of H.S. Hall and F.H. Stevens , 'A Shorter School Geometry, Part 1, Metric Edition'. In page 134 of this book, the authors present, in exercise 4, a practical construction which leads to a verification of the Pythagorean theorem. Subsequently in Theorems 29 and 30, the authors present the standard proofs of the Pythagorean theorem and its converse. In page 140, the authors present, in exercise 15, what amounts to a geometric construction, whose verification involves a simple algebraic identity. Both the constructions are of great importance and can be replicated by using the standard equipment provided in a 'geometry toolbox' carried by students in high schools. The author hopes that the results proved in this paper, in conjunction with the two constructions from the above-mentioned book, would provide high school students an appreciation of the celebrated theorem of Pythagoras. The diagrams that accompany this document are based on the free software GeoGebra. The author formally acknowledges his indebtedness to the creators of this free software at the end of this document.
Total cross sections for positron and electron scattering from pyrimidine

International Nuclear Information System (INIS)

Zecca, A; Chiari, L; Trainotti, E; GarcIa, G; Blanco, F; Brunger, M J

2010-01-01

In this paper we report original measurements of total cross sections for positron scattering from the important biomolecule pyrimidine. The energy range of these measurements was 0.3-45 eV, while the energy resolution was ∼260 meV. In addition, we report theoretical results, calculated within the independent atom-screened additivity rule (IAM-SCAR) formalism, for the corresponding electron impact total cross sections. In that case the energy range is 1-10 000 eV. Total cross sections are very important input data for codes that seek to simulate charged-particle tracks in matter, as they define the mean-free path between collisions. As the present data and computations are to the best of our knowledge the first total cross sections to be reported for either positron or electron scattering from pyrimidine, they fill an important void in our available knowledge in the literature.
AtomPy: An Open Atomic Data Curation Environment for Astrophysical Applications

Directory of Open Access Journals (Sweden)

Claudio Mendoza

2014-05-01

Full Text Available We present a cloud-computing environment, referred to as AtomPy, based on Google-Drive Sheets and Pandas (Python Data Analysis Library DataFrames to promote community-driven curation of atomic data for astrophysical applications, a stage beyond database development. The atomic model for each ionic species is contained in a multi-sheet workbook, tabulating representative sets of energy levels, A-values and electron impact effective collision strengths from different sources. The relevant issues that AtomPy intends to address are: (i data quality by allowing open access to both data producers and users; (ii comparisons of different datasets to facilitate accuracy assessments; (iii downloading to local data structures (i.e., Pandas DataFrames for further manipulation and analysis by prospective users; and (iv data preservation by avoiding the discard of outdated sets. Data processing workﬂows are implemented by means of IPython Notebooks, and collaborative software developments are encouraged and managed within the GitHub social network. The facilities of AtomPy are illustrated with the critical assessment of the transition probabilities for ions in the hydrogen and helium isoelectronic sequences with atomic number Z ≤ 10.
Application of least square support vector machine and multivariate adaptive regression spline models in long term prediction of river water pollution

Science.gov (United States)

Kisi, Ozgur; Parmar, Kulwinder Singh

2016-03-01

This study investigates the accuracy of least square support vector machine (LSSVM), multivariate adaptive regression splines (MARS) and M5 model tree (M5Tree) in modeling river water pollution. Various combinations of water quality parameters, Free Ammonia (AMM), Total Kjeldahl Nitrogen (TKN), Water Temperature (WT), Total Coliform (TC), Fecal Coliform (FC) and Potential of Hydrogen (pH) monitored at Nizamuddin, Delhi Yamuna River in India were used as inputs to the applied models. Results indicated that the LSSVM and MARS models had almost same accuracy and they performed better than the M5Tree model in modeling monthly chemical oxygen demand (COD). The average root mean square error (RMSE) of the LSSVM and M5Tree models was decreased by 1.47% and 19.1% using MARS model, respectively. Adding TC input to the models did not increase their accuracy in modeling COD while adding FC and pH inputs to the models generally decreased the accuracy. The overall results indicated that the MARS and LSSVM models could be successfully used in estimating monthly river water pollution level by using AMM, TKN and WT parameters as inputs.
Kinetic-energy density functional: Atoms and shell structure

International Nuclear Information System (INIS)

Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

1996-01-01

We present a nonlocal kinetic-energy functional which includes an anisotropic average of the density through a symmetrization procedure. This functional allows a better description of the nonlocal effects of the electron system. The main consequence of the symmetrization is the appearance of a clear shell structure in the atomic density profiles, obtained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incipient structures for heavy atoms, only our functional shows a clear shell structure for most of the atoms. The atomic total energies have a good agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems. copyright 1996 The American Physical Society
Least-squares collocation meshless approach for radiative heat transfer in absorbing and scattering media

Science.gov (United States)

Liu, L. H.; Tan, J. Y.

2007-02-01

A least-squares collocation meshless method is employed for solving the radiative heat transfer in absorbing, emitting and scattering media. The least-squares collocation meshless method for radiative transfer is based on the discrete ordinates equation. A moving least-squares approximation is applied to construct the trial functions. Except for the collocation points which are used to construct the trial functions, a number of auxiliary points are also adopted to form the total residuals of the problem. The least-squares technique is used to obtain the solution of the problem by minimizing the summation of residuals of all collocation and auxiliary points. Three numerical examples are studied to illustrate the performance of this new solution method. The numerical results are compared with the other benchmark approximate solutions. By comparison, the results show that the least-squares collocation meshless method is efficient, accurate and stable, and can be used for solving the radiative heat transfer in absorbing, emitting and scattering media.
Least-squares collocation meshless approach for radiative heat transfer in absorbing and scattering media

International Nuclear Information System (INIS)

Liu, L.H.; Tan, J.Y.

2007-01-01

A least-squares collocation meshless method is employed for solving the radiative heat transfer in absorbing, emitting and scattering media. The least-squares collocation meshless method for radiative transfer is based on the discrete ordinates equation. A moving least-squares approximation is applied to construct the trial functions. Except for the collocation points which are used to construct the trial functions, a number of auxiliary points are also adopted to form the total residuals of the problem. The least-squares technique is used to obtain the solution of the problem by minimizing the summation of residuals of all collocation and auxiliary points. Three numerical examples are studied to illustrate the performance of this new solution method. The numerical results are compared with the other benchmark approximate solutions. By comparison, the results show that the least-squares collocation meshless method is efficient, accurate and stable, and can be used for solving the radiative heat transfer in absorbing, emitting and scattering media
Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: A comparative study

International Nuclear Information System (INIS)

Cabon, J.Y.; Giamarchi, P.; Le Bihan, A.

2010-01-01

Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L -1 (20 μL, 3σ) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3σ) of 3 ng L -1 (i.e. 54 pM) for total Fe concentration with the use a 20 μL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 μg L -1 ) seawater sample were in good agreement with the certified values.
Chemical potential of molecules contrasted to averaged atomic electronegativities: alarming differences and their theoretical rationalization.

Science.gov (United States)

Datta, Dipankar; Shee, Nirmal K; von Szentpály, László

2013-01-10

We present the first large-scale empirical examination of the relation of molecular chemical potentials, μ(0)(mol) = -½(I(0) + A(0))(mol), to the geometric mean (GM) of atomic electronegativities, (GM) = (GM), and demonstrate that μ(0)(mol) ≠ -(GM). Out of 210 molecular μ(0)(mol)values considered more than 150 are not even in the range min{μ(0)(at)} (GM). For this equation the root-mean-square of relative errors amounts to SE = 71%. Our results are at strong variance with Sanderson's electronegativity equalization principle and present a challenge to some popular practice in conceptual density functional theory (DFT). The influences of the "external" potential and charge dependent covalent and ionic binding contributions are discussed and provide the theoretical rationalization for the empirical facts. Support is given to the warnings by Hinze, Bader et al., Allen, and Politzer et al. that equating the chemical potential to the negative of electronegativity may lead to misconceptions.
Graphs whose complement and square are isomorphic

DEFF Research Database (Denmark)

Pedersen, Anders Sune

2014-01-01

We study square-complementary graphs, that is, graphs whose complement and square are isomorphic. We prove several necessary conditions for a graph to be square-complementary, describe ways of building new square-complementary graphs from existing ones, construct infinite families of square-compl...
The Definition Method and Optimization of Atomic Strain Tensors for Nuclear Power Engineering Materials

Directory of Open Access Journals (Sweden)

Xiangguo Zeng

2016-01-01

Full Text Available A common measure of deformation between atomic scale simulations and the continuum framework is provided and the strain tensors for multiscale simulations are defined in this paper. In order to compute the deformation gradient of any atom m, the weight function is proposed to eliminate the different contributions within the neighbor atoms which have different distances to atom m, and the weighted least squares error optimization model is established to seek the optimal coefficients of the weight function and the optimal local deformation gradient of each atom. The optimization model involves more than 9 parameters. To guarantee the reliability of subsequent parameters identification result and lighten the calculation workload of parameters identification, an overall analysis method of parameter sensitivity and an advanced genetic algorithm are also developed.

Low-Temperature Crystal Structures of the Hard Core Square Shoulder Model

Directory of Open Access Journals (Sweden)

Alexander Gabriëlse

2017-11-01

Full Text Available In many cases, the stability of complex structures in colloidal systems is enhanced by a competition between different length scales. Inspired by recent experiments on nanoparticles coated with polymers, we use Monte Carlo simulations to explore the types of crystal structures that can form in a simple hard-core square shoulder model that explicitly incorporates two favored distances between the particles. To this end, we combine Monte Carlo-based crystal structure finding algorithms with free energies obtained using a mean-field cell theory approach, and draw phase diagrams for two different values of the square shoulder width as a function of the density and temperature. Moreover, we map out the zero-temperature phase diagram for a broad range of shoulder widths. Our results show the stability of a rich variety of crystal phases, such as body-centered orthogonal (BCO lattices not previously considered for the square shoulder model.
Vortex-induced vibrations of a square cylinder under linear shear flow

Energy Technology Data Exchange (ETDEWEB)

Sun, Wenjuan; Zhou, Dai; Han, Zhaolong [School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Tu, Jiahuang, E-mail: tujiahuang1982@163.com, E-mail: han.arkey@gmail.com [College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan, Hunan 411105 (China)

2017-04-15

This paper investigates the numerical vortex-induced vibration (VIV) of a square cylinder which is connected to a 2-DOF mass-spring system and is immersed in the planar shear flow by employing a characteristic-based split (CBS) finite element method (FEM). The reduced mass of the square cylinder is M {sub r} = 2, while the reduced velocity, U {sub r}, is changed from 3 to 12 with an increment of Δ U {sub r} = 1. The effects of some key parameters on the cylinder dynamic responses, vibrating frequencies, the flow patterns as well as the energy transferred between the fluid and cylinder are revealed. In this study, the key parameters are selected as follows: shear ratio ( k = 0, 0.05 and 0.1) and Reynolds numbers ( Re = 80 and 160). Numerical results demonstrate that the X – Y trajectories of the cylinder mainly appear as a symmetrical figure ‘8’ in uniform flow ( k = 0) and an unsymmetrical figure ‘8’ and ‘O’ in shear flows ( k = 0.05 and 0.1). The maximum oscillation amplitudes of the square cylinder in both the inline and transverse directions have distinct characteristics compared to that of a circular cylinder. Two kinds of flow patterns, ‘2S’ and ‘P + S’, are mainly observed under the shear flow. Also, the mean values of the energy of the cylinder system increase with the reduced velocity, while the root mean square (rms) of the energy reaches its peak value at reduced velocity U {sub r} = 5. (paper)
Microwave digestion for determination content of iron and zinc total in food

International Nuclear Information System (INIS)

Silva Trejos, Paulina

2012-01-01

The food digestion procedure was optimized by means of a microwave oven, to quantify the iron and total zinc in different matrices by atomic absorption spectroscopy. The optimum amount of concentrated HNO 3 was analyzed at 65% to digest sample mass determined by assessment of the percentage of recovery obtained with different amount of HNO 3 . The results have not differed from those obtained by officially recommended methods of acid digestion in open systems and calcination. (author) [es
Self-diffusion of particles interacting through a square-well or square-shoulder potential

NARCIS (Netherlands)

Wilbertz, H.; Michels, J.; Beijeren, H. van; Leegwater, J.A.

1988-01-01

The diffusion coefficient and velocity autocorrelation function for a fluid of particles interacting through a square-well or square-shoulder potential are calculated from a kinetic theory similar to the Davis-Rice-Sengers theory and the results are compared to those of computer simulations. At low
Collision-produced atomic states

International Nuclear Information System (INIS)

Andersen, N.; Copenhagen Univ.

1988-01-01

The last 10-15 years have witnessed the development of a new, powerful class of experimental techniques for atomic collision studies, allowing partial or complete determination of the state of the atoms after a collision event, i.e. the full set of quantum-mechanical scattering amplitudes or - more generally - the density matrix describing the system. Evidently, such studies, involving determination of alignment and orientation parameters, provide much more severe tests of state-of-the-art scattering theories than do total or differential cross section measurements which depend on diagonal elements of the density matrix. The off-diagonal elements give us detailed information about the shape and dynamics of the atomic states. Therefore, close studies of collision-produced atomic states are currently leading to deeper insights into the fundamental physical mechanisms governing the dynamics of atomic collision events. The first part of the lectures deals with the language used to describe atomic states, while the second part presents a selection of recent results for model systems which display fundamental aspects of the collision physics in particularly instructive ways. I shall here restrict myself to atom-atom collisions. The discussion will be focused on states decaying by photon emission though most of the ideas can be easily modified to include electron emission as well. (orig./AH)
Improvement of Frequency Locking Algorithm for Atomic Frequency Standards

Science.gov (United States)

Park, Young-Ho; Kang, Hoonsoo; Heyong Lee, Soo; Eon Park, Sang; Lee, Jong Koo; Lee, Ho Seong; Kwon, Taeg Yong

2010-09-01

The authors describe a novel method of frequency locking algorithm for atomic frequency standards. The new algorithm for locking the microwave frequency to the Ramsey resonance is compared with the old one that had been employed in the cesium atomic beam frequency standards such as NIST-7 and KRISS-1. Numerical simulations for testing the performance of the algorithm show that the new method has a noise filtering performance superior to the old one by a factor of 1.2 for the flicker signal noise and 1.4 for random-walk signal noise. The new algorithm can readily be used to enhance the frequency stability for a digital servo employing the slow square wave frequency modulation.
Double ionization of atoms by ion impact: two-step models

Energy Technology Data Exchange (ETDEWEB)

Fiori, Marcelo [Departamento de Fisica, Universidad Nacional de Salta, Salta (Argentina); Rocha, A B [Instituto de Quimica, Departamento de FIsico-Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21949-900, RJ (Brazil); Bielschowsky, C E [Instituto de Quimica, Departamento de FIsico-Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21949-900, RJ (Brazil); Jalbert, Ginette [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, 21941-972, RJ (Brazil); Garibotti, C R [CONICET and Centro Atomico Bariloche, 8400 S. C. Bariloche, RIo Negro (Argentina)

2006-04-14

Total cross sections for the double ionization of He and Li atoms by the impact of H{sup +}, He{sup 2+} and Li{sup 3+} are calculated at intermediate and high energies within two-step models. The double ionization of He by the impact of other bare projectiles at a fixed energy is obtained as well. Single ionization probabilities are calculated within the continuum distorted wave -eikonal-initial-state (CDW-EIS) approximation. The required atomic bound and continuum wave functions are evaluated by numerically solving the atomic wave equation with an optimized potential model (OPM). Correlation between events is introduced by considering ion relaxation. The final state electronic correlation is considered by means of the so-called Gamow factor. We compare the transition probabilities resulting from our approach with those resulting from the use of a Rootham-Hartree-Fock initial state and a Coulomb continuum state with an effective charge. We find that the use of OPM waves gives a better agreement with the experimental results than with Coulomb waves.
Salt-and-pepper noise removal using modified mean filter and total variation minimization

Science.gov (United States)

Aghajarian, Mickael; McInroy, John E.; Wright, Cameron H. G.

2018-01-01

The search for effective noise removal algorithms is still a real challenge in the field of image processing. An efficient image denoising method is proposed for images that are corrupted by salt-and-pepper noise. Salt-and-pepper noise takes either the minimum or maximum intensity, so the proposed method restores the image by processing the pixels whose values are either 0 or 255 (assuming an 8-bit/pixel image). For low levels of noise corruption (less than or equal to 50% noise density), the method employs the modified mean filter (MMF), while for heavy noise corruption, noisy pixels values are replaced by the weighted average of the MMF and the total variation of corrupted pixels, which is minimized using convex optimization. Two fuzzy systems are used to determine the weights for taking average. To evaluate the performance of the algorithm, several test images with different noise levels are restored, and the results are quantitatively measured by peak signal-to-noise ratio and mean absolute error. The results show that the proposed scheme gives considerable noise suppression up to a noise density of 90%, while almost completely maintaining edges and fine details of the original image.
Water cut measurement of oil–water flow in vertical well by combining total flow rate and the response of a conductance probe

International Nuclear Information System (INIS)

Chen, Jianjun; Xu, Lijun; Cao, Zhang; Zhang, Wen; Liu, Xingbin; Hu, Jinhai

2015-01-01

In this paper, a conductance probe-based well logging instrument was developed and the total flow rate is combined with the response of the conductance probe to estimate the water cut of the oil–water flow in a vertical well. The conductance probe records the time-varying electrical characteristics of the oil–water flow. Linear least squares regression (LSR) and nonlinear support vector regression (SVR) were used to establish models to map the total flow rate and features extracted from the probe response onto the water cut, respectively. Principal component analysis (PCA) and partial least squares analysis (PLSA) techniques were employed to reduce data redundancy within the extracted features. An experiment was carried out in a vertical pipe with an inner diameter of 125 mm and a height of 24 m in an experimental multi-phase flow setup, Daqing Oilfield, China. In the experiment, oil–water flow was used and the total flow rate varied from 10 to 200 m 3 per day and the water cut varied from 0% to 100%. As a direct comparison, the cases were also studied when the total flow rate was not used as an independent input to the models. The results obtained demonstrate that: (1) the addition of the total flow rate as an input to the regression models can greatly improve the accuracy of water cut prediction, (2) the nonlinear SVR model performs much better than the linear LSR model, and (3) for the SVR model with the total flow rate as an input, the adoption of PCA or PLSA not only decreases the dimensions of inputs, but also increases prediction accuracy. The SVR model with five PCA-treated features plus the total flow rate achieves the best performance in water cut prediction, with a coefficient of determination (R 2 ) as high as 0.9970. The corresponding root mean squared error (RMSE) and mean quoted error (MQE) are 0.0312% and 1.99%, respectively. (paper)
Atomic diffusion in stars

CERN Document Server

Michaud, Georges; Richer, Jacques

2015-01-01

This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling. In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...
Molecular dynamics study of silver

International Nuclear Information System (INIS)

Akhter, J.I.; Yaldram, K.; Ahmad, W.; Khan, M.K.; Rehman, T.S.

1995-03-01

We present results of molecular dynamics study using the embedded atom potential to examine the equilibrium bulk properties of Ag. We calculate the total energy and the lattice parameters as a function of temperature. From these we determine the specific heat and linear coefficient of thermal expansion. The comparison with experimental results of these two quantities is found to be excellent. We have also calculated the mean square displacement of the atoms in the three directions. As expected because of symmetry the displacements in the three directions are comparable and increase with increasing temperature. (author) 5 figs
A TRMM/GPM retrieval of the total mean generator current for the global electric circuit

Science.gov (United States)

Peterson, Michael; Deierling, Wiebke; Liu, Chuntao; Mach, Douglas; Kalb, Christina

2017-09-01

A specialized satellite version of the passive microwave electric field retrieval algorithm (Peterson et al., 2015) is applied to observations from the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) satellites to estimate the generator current for the Global Electric Circuit (GEC) and compute its temporal variability. By integrating retrieved Wilson currents from electrified clouds across the globe, we estimate a total mean current of between 1.4 kA (assuming the 7% fraction of electrified clouds producing downward currents measured by the ER-2 is representative) to 1.6 kA (assuming all electrified clouds contribute to the GEC). These current estimates come from all types of convective weather without preference, including Electrified Shower Clouds (ESCs). The diurnal distribution of the retrieved generator current is in excellent agreement with the Carnegie curve (RMS difference: 1.7%). The temporal variability of the total mean generator current ranges from 110% on semi-annual timescales (29% on an annual timescale) to 7.5% on decadal timescales with notable responses to the Madden-Julian Oscillation and El Nino Southern Oscillation. The geographical distribution of current includes significant contributions from oceanic regions in addition to the land-based tropical chimneys. The relative importance of the Americas and Asia chimneys compared to Africa is consistent with the best modern ground-based observations and further highlights the importance of ESCs for the GEC.
Control of the dynamics of coupled atomic-molecular Bose-Einstein condensates: Modified Gross-Pitaevskii approach

International Nuclear Information System (INIS)

Gupta, Moumita; Dastidar, Krishna Rai

2009-01-01

We study the dynamics of the atomic and molecular Bose-Einstein condensates (BECs) of 87 Rb in a spherically symmetric trap coupled by stimulated Raman photoassociation process. Considering the higher order nonlinearity in the atom-atom interaction we analyze the dynamics of the system using coupled modified Gross-Pitaevskii (MGP) equations and compare it with mean-field coupled Gross-Pitaevskii (GP) dynamics. Considerable differences in the dynamics are obtained in these two approaches at large scattering length, i.e., for large values of peak-gas parameter x pk ≥10 -3 . We show how the dynamics of the coupled system is affected when the atom-molecule and molecule-molecule interactions are considered together with the atom-atom interaction and also when the strengths of these three interactions are increased. The effect of detuning on the efficiency of conversion of atomic fractions into molecules is demonstrated and the feasibility of maximum molecular BEC formation by varying the Raman detuning parameter at different values of time is explored. Thus by varying the Raman detuning and the scattering length for atom-atom interaction one can control the dynamics of the coupled atomic-molecular BEC system. We have also solved coupled Gross-Pitaevskii equations for atomic to molecular condensate formation through magnetic Feshbach resonance in a BEC of 85 Rb. We found similar features for oscillations between atomic and molecular condensates noted in previous theoretical study and obtained fairly good agreement with the evolution of total atomic condensate observed experimentally.
MO-DE-207A-10: One-Step CT Reconstruction for Metal Artifact Reduction by a Modification of Penalized Weighted Least-Squares (PWLS)

Energy Technology Data Exchange (ETDEWEB)

Kim, H; Chen, J [University of California San Francisco, San Francisco, CA (United States)

2016-06-15

Purpose: Metal objects create severe artifacts in kilo-voltage (kV) CT image reconstructions due to the high attenuation coefficients of high atomic number objects. Most of the techniques devised to reduce this artifact utilize a two-step approach, which do not reliably yield the qualified reconstructed images. Thus, for accuracy and simplicity, this work presents a one-step reconstruction method based on a modified penalized weighted least-squares (PWLS) technique. Methods: Existing techniques for metal artifact reduction mostly adopt a two-step approach, which conduct additional reconstruction with the modified projection data from the initial reconstruction. This procedure does not consistently perform well due to the uncertainties in manipulating the metal-contaminated projection data by thresholding and linear interpolation. This study proposes a one-step reconstruction process using a new PWLS operation with total-variation (TV) minimization, while not manipulating the projection. The PWLS for CT reconstruction has been investigated using a pre-defined weight, based on the variance of the projection datum at each detector bin. It works well when reconstructing CT images from metal-free projection data, which does not appropriately penalize metal-contaminated projection data. The proposed work defines the weight at each projection element under the assumption of a Poisson random variable. This small modification using element-wise penalization has a large impact in reducing metal artifacts. For evaluation, the proposed technique was assessed with two noisy, metal-contaminated digital phantoms, against the existing PWLS with TV minimization and the two-step approach. Result: The proposed PWLS with TV minimization greatly improved the metal artifact reduction, relative to the other techniques, by watching the results. Numerically, the new approach lowered the normalized root-mean-square error about 30 and 60% for the two cases, respectively, compared to the two
Transport and interaction blockade of cold bosonic atoms in a triple-well potential

International Nuclear Information System (INIS)

Schlagheck, P; Malet, F; Cremon, J C; Reimann, S M

2010-01-01

We theoretically investigate the transport properties of cold bosonic atoms in a quasi-one-dimensional (1D) triple-well potential that consists of two large outer wells, which act as microscopic source and drain reservoirs, and a small inner well, which represents a quantum-dot-like scattering region. Bias and gate 'voltages' introduce a time-dependent tilt of the triple-well configuration, and are used to shift the energetic level of the inner well with respect to the outer ones. By means of exact diagonalization considering a total number of six atoms in the triple-well potential, we find diamond-like structures for the occurrence of single-atom transport in the parameter space spanned by the bias and gate voltages. We discuss the analogy with Coulomb blockade in electronic quantum dots, and point out how one can infer the interaction energy in the central well from the distance between the diamonds.
Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: a comparative study.

Science.gov (United States)

Cabon, J Y; Giamarchi, P; Le Bihan, A

2010-04-07

Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L(-1) (20 microL, 3sigma) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3sigma) of 3 ng L(-1) (i.e. 54 pM) for total Fe concentration with the use a 20 microL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 microg L(-1)) seawater sample were in good agreement with the certified values. Copyright 2010 Elsevier B.V. All rights reserved.
Study on Fluid-Induced Vibration Power Harvesting of Square Columns under Different Attack Angles

Directory of Open Access Journals (Sweden)

Meng Zhang

2017-01-01

Full Text Available A model of the flow-vibration-electrical circuit multiphysical coupling system for solving square column vortex-induced vibration piezoelectric energy harvesting (VIVPEH is proposed in this paper. The quasi steady state theory is adopted to describe the fluid solid coupling process of vortex-induced vibration based on the finite volume method coupled Gauss equation. The vibrational response and the quasi steady state form of the output voltage are solved by means of the matrix coefficient method and interactive computing. The results show that attack angles play an important role in the performance of square column VIVPEH, of which α=45° is a relatively ideal attack angle of square column VIVPEH.
A Parametric k-Means Algorithm

Science.gov (United States)

Tarpey, Thaddeus

2007-01-01

Summary The k points that optimally represent a distribution (usually in terms of a squared error loss) are called the k principal points. This paper presents a computationally intensive method that automatically determines the principal points of a parametric distribution. Cluster means from the k-means algorithm are nonparametric estimators of principal points. A parametric k-means approach is introduced for estimating principal points by running the k-means algorithm on a very large simulated data set from a distribution whose parameters are estimated using maximum likelihood. Theoretical and simulation results are presented comparing the parametric k-means algorithm to the usual k-means algorithm and an example on determining sizes of gas masks is used to illustrate the parametric k-means algorithm. PMID:17917692
Atomic Reference Data for Electronic Structure Calculations

CERN Document Server

Kotochigova, S; Shirley, E L

We have generated data for atomic electronic structure calculations, to provide a standard reference for results of specified accuracy under commonly used approximations. Results are presented here for total energies and orbital energy eigenvalues for all atoms from H to U, at microHartree accuracy in the total energy, as computed in the local-density approximation (LDA) the local-spin-density approximation (LSD); the relativistic local-density approximation (RLDA); and scalar-relativistic local-density approximation (ScRLDA).
Surface-Initiated Atom Transfer Radical Polymerization and Electrografting Technique as a Means For Attaining Tailor-Made Polymer Coatings

DEFF Research Database (Denmark)

Chernyy, Sergey

2012-01-01

strategies for initiator grafting, physicochemical properties of polymer brushes and basic principles of quartz crystal microbalance technique (QCM) are discussed. In Chapter 2 various ATRP conditions are probed. The effects of solvent polarity, monomer concentration, initiator surface density, ligand nature......Atom transfer radical polymerization initiated from a surface of various substrates (SI-ATRP) has become a progressively popular technique for obtaining thin polymer films with predetermined properties. The present work addresses the main features of SI-ATRP with respect to the controllability...... and temperature on the kinetics of methyl methacrylate polymerization are elucidated. The strategy was based on the observation of dry polymer thickness versus time evolution by means of ellipsometry, profilometry and IR spectroscopy. An alternative approach, constituting Chapter 3, was based on optimization...

A new atomic model

International Nuclear Information System (INIS)

Petrescu, Florian Ion

2012-01-01

The movement of an electron around the atomic nucleus has today a great importance in many engineering fields. Electronics, aeronautics, micro and nanotechnology, electrical engineering, optics, lasers, nuclear power, computing, equipment and automation, telecommunications, genetic engineering, bioengineering, special processing, modern welding, robotics, energy and electromagnetic wave field is today only a few of the many applications of electronic engineering. This book presents, shortly, a new and original relation (20 and 20') who determines the radius with that, the electron is running around the nucleus of an atom. One utilizes, two times the Lorenz relation, the Niels Bohr generalized equation, and a mass relation, which was deduced from the kinematics energy relation written in two modes: classical and Coulombian. Equalizing the mass relation with Lorenz relation one obtains a form which is a relation between the squared electron speed (v 2 ) and the radius (r). The second relation between v 2 and r was obtained by equalizing the mass of Bohr equation and the mass of Lorenz relation. For a Bohr energetically level (n=a constant value), one determines now two energetically below levels, which form an electronic layer. The author realizes by this a new atomic model, or a new quantum theory, which explains the existence of electron-clouds without spin.Writing the kinematics energy relation in two modes, classical and Coulombian one determines a relation, from which explicitely the mass of the electron is determined.
A new atomic model

Energy Technology Data Exchange (ETDEWEB)

Petrescu, Florian Ion

2012-07-01

The movement of an electron around the atomic nucleus has today a great importance in many engineering fields. Electronics, aeronautics, micro and nanotechnology, electrical engineering, optics, lasers, nuclear power, computing, equipment and automation, telecommunications, genetic engineering, bioengineering, special processing, modern welding, robotics, energy and electromagnetic wave field is today only a few of the many applications of electronic engineering. This book presents, shortly, a new and original relation (20 and 20') who determines the radius with that, the electron is running around the nucleus of an atom. One utilizes, two times the Lorenz relation, the Niels Bohr generalized equation, and a mass relation, which was deduced from the kinematics energy relation written in two modes: classical and Coulombian. Equalizing the mass relation with Lorenz relation one obtains a form which is a relation between the squared electron speed (v{sup 2}) and the radius (r). The second relation between v{sup 2} and r was obtained by equalizing the mass of Bohr equation and the mass of Lorenz relation. For a Bohr energetically level (n=a constant value), one determines now two energetically below levels, which form an electronic layer. The author realizes by this a new atomic model, or a new quantum theory, which explains the existence of electron-clouds without spin.Writing the kinematics energy relation in two modes, classical and Coulombian one determines a relation, from which explicitely the mass of the electron is determined.
36 CFR 910.67 - Square guidelines.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Square guidelines. 910.67... GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Glossary of Terms § 910.67 Square guidelines. Square Guidelines establish the Corporation's...
A Note on Magic Squares

Science.gov (United States)

Williams, Horace E.

1974-01-01

A method for generating 3x3 magic squares is developed. A series of questions relating to these magic squares is posed. An invesitgation using matrix methods is suggested with some questions for consideration. (LS)
Superfluorescence with cold trapped neon atoms

International Nuclear Information System (INIS)

Zachorowski, Jerzy

2003-01-01

A method for observation of superfluorescence in a cloud of cold metastable Ne atoms is proposed. Means of achieving a cold sample of trapped metastable atoms are discussed. The feasibility of obtaining conditions for a superfluorescence pulse is studied. The paper also discusses the prospects for obtaining intense pulses of extreme ultraviolet radiation
Democracy Squared

DEFF Research Database (Denmark)

Rose, Jeremy; Sæbø, Øystein

2005-01-01

On-line political communities, such as the Norwegian site Demokratitorget (Democracy Square), are often designed according to a set of un-reflected assumptions about the political interests of their potential members. In political science, democracy is not taken as given in this way, but can...... be represented by different models which characterize different relationships between politicians and the citizens they represent. This paper uses quantitative and qualitative content analysis to analyze the communication mediated by the Democracy Square discussion forum in the first ten months of its life......-Republican model. In the qualitative analysis the discourse is analysed as repeating genres – patterns in the communication form which also reflect the conflict of interest between citizens and politicians. Though the analysis gives insight into the nature of the discourse the site supports, little is known about...
Feasibility study on the least square method for fitting non-Gaussian noise data

Science.gov (United States)

Xu, Wei; Chen, Wen; Liang, Yingjie

2018-02-01

This study is to investigate the feasibility of least square method in fitting non-Gaussian noise data. We add different levels of the two typical non-Gaussian noises, Lévy and stretched Gaussian noises, to exact value of the selected functions including linear equations, polynomial and exponential equations, and the maximum absolute and the mean square errors are calculated for the different cases. Lévy and stretched Gaussian distributions have many applications in fractional and fractal calculus. It is observed that the non-Gaussian noises are less accurately fitted than the Gaussian noise, but the stretched Gaussian cases appear to perform better than the Lévy noise cases. It is stressed that the least-squares method is inapplicable to the non-Gaussian noise cases when the noise level is larger than 5%.
Correlation between the plasma characteristics and the surface chemistry of plasma-treated polymers through partial least-squares analysis.

Science.gov (United States)

Mavadat, Maryam; Ghasemzadeh-Barvarz, Massoud; Turgeon, Stéphane; Duchesne, Carl; Laroche, Gaétan

2013-12-23

We investigated the effect of various plasma parameters (relative density of atomic N and H, plasma temperature, and vibrational temperature) and process conditions (pressure and H2/(N2 + H2) ratio) on the chemical composition of modified poly(tetrafluoroethylene) (PTFE). The plasma parameters were measured by means of near-infrared (NIR) and UV-visible emission spectroscopy with and without actinometry. The process conditions of the N2-H2 microwave discharges were set at various pressures ranging from 100 to 2000 mTorr and H2/(N2+H2) gas mixture ratios between 0 and 0.4. The surface chemical composition of the modified polymers was determined by X-ray photoelectron spectroscopy (XPS). A mathematical model was constructed using the partial least-squares regression algorithm to correlate the plasma information (process condition and plasma parameters as determined by emission spectroscopy) with the modified surface characteristics. To construct the model, a set of data input variables containing process conditions and plasma parameters were generated, as well as a response matrix containing the surface composition of the polymer. This model was used to predict the composition of PTFE surfaces subjected to N2-H2 plasma treatment. Contrary to what is generally accepted in the literature, the present data demonstrate that hydrogen is not directly involved in the defluorination of the surface but rather produces atomic nitrogen and/or NH radicals that are shown to be at the origin of fluorine atom removal from the polymer surface. The results show that process conditions alone do not suffice in predicting the surface chemical composition and that the plasma characteristics, which cannot be easily correlated with these conditions, should be considered. Process optimization and control would benefit from plasma diagnostics, particularly infrared emission spectroscopy.
Estimating Atomic Contributions to Hydration and Binding Using Free Energy Perturbation.

Science.gov (United States)

Irwin, Benedict W J; Huggins, David J

2018-05-08

We present a general method called atom-wise free energy perturbation (AFEP), which extends a conventional molecular dynamics free energy perturbation (FEP) simulation to give the contribution to a free energy change from each atom. AFEP is derived from an expansion of the Zwanzig equation used in the exponential averaging method by defining that the system total energy can be partitioned into contributions from each atom. A partitioning method is assumed and used to group terms in the expansion to correspond to individual atoms. AFEP is applied to six example free energy changes to demonstrate the method. Firstly, the hydration free energies of methane, methanol, methylamine, methanethiol, and caffeine in water. AFEP highlights the atoms in the molecules that interact favorably or unfavorably with water. Finally AFEP is applied to the binding free energy of human immunodeficiency virus type 1 protease to lopinavir, and AFEP reveals the contribution of each atom to the binding free energy, indicating candidate areas of the molecule to improve to produce a more strongly binding inhibitor. FEP gives a single value for the free energy change and is already a very useful method. AFEP gives a free energy change for each "part" of the system being simulated, where part can mean individual atoms, chemical groups, amino acids, or larger partitions depending on what the user is trying to measure. This method should have various applications in molecular dynamics studies of physical, chemical, or biochemical phenomena, specifically in the field of computational drug discovery.
SU-F-T-408: On the Determination of Equivalent Squares for Rectangular Small MV Photon Fields

International Nuclear Information System (INIS)

Sauer, OA; Wegener, S; Exner, F

2016-01-01

Purpose: It is common practice to tabulate dosimetric data like output factors, scatter factors and detector signal correction factors for a set of square fields. In order to get the data for an arbitrary field, it is mapped to an equivalent square, having the same scatter as the field of interest. For rectangular fields both, tabulated data and empiric formula exist. We tested the applicability of such rules for very small fields. Methods: Using the Monte-Carlo method (EGSnrc-doseRZ), the dose to a point in 10cm depth in water was calculated for cylindrical impinging fluence distributions. Radii were from 0.5mm to 11.5mm with 1mm thickness of the rings. Different photon energies were investigated. With these data a matrix was constructed assigning the amount of dose to the field center to each matrix element. By summing up the elements belonging to a certain field, the dose for an arbitrary point in 10cm depth could be determined. This was done for rectangles up to 21mm side length. Comparing the dose to square field results, equivalent squares could be assigned. The results were compared to using the geometrical mean and the 4Xperimeter/area rule. Results: For side length differences less than 2mm, the difference between all methods was in general less than 0.2mm. For more elongated fields, relevant differences of more than 1mm and up to 3mm for the fields investigated occurred. The mean square side length calculated from both empiric formulas fitted much better, deviating hardly more than 1mm and for the very elongated fields only. Conclusion: For small rectangular photon fields, deviating only moderately from square both investigated empiric methods are sufficiently accurate. As the deviations often differ regarding their sign, using the mean improves the accuracy and the useable elongation range. For ratios larger than 2, Monte-Carlo generated data are recommended. SW is funded by Deutsche Forschungsgemeinschaft (SA481/10-1)
SU-F-T-408: On the Determination of Equivalent Squares for Rectangular Small MV Photon Fields

Energy Technology Data Exchange (ETDEWEB)

Sauer, OA; Wegener, S; Exner, F [University of Wuerzburg, Wuerzburg (Germany)

2016-06-15

Purpose: It is common practice to tabulate dosimetric data like output factors, scatter factors and detector signal correction factors for a set of square fields. In order to get the data for an arbitrary field, it is mapped to an equivalent square, having the same scatter as the field of interest. For rectangular fields both, tabulated data and empiric formula exist. We tested the applicability of such rules for very small fields. Methods: Using the Monte-Carlo method (EGSnrc-doseRZ), the dose to a point in 10cm depth in water was calculated for cylindrical impinging fluence distributions. Radii were from 0.5mm to 11.5mm with 1mm thickness of the rings. Different photon energies were investigated. With these data a matrix was constructed assigning the amount of dose to the field center to each matrix element. By summing up the elements belonging to a certain field, the dose for an arbitrary point in 10cm depth could be determined. This was done for rectangles up to 21mm side length. Comparing the dose to square field results, equivalent squares could be assigned. The results were compared to using the geometrical mean and the 4Xperimeter/area rule. Results: For side length differences less than 2mm, the difference between all methods was in general less than 0.2mm. For more elongated fields, relevant differences of more than 1mm and up to 3mm for the fields investigated occurred. The mean square side length calculated from both empiric formulas fitted much better, deviating hardly more than 1mm and for the very elongated fields only. Conclusion: For small rectangular photon fields, deviating only moderately from square both investigated empiric methods are sufficiently accurate. As the deviations often differ regarding their sign, using the mean improves the accuracy and the useable elongation range. For ratios larger than 2, Monte-Carlo generated data are recommended. SW is funded by Deutsche Forschungsgemeinschaft (SA481/10-1)
TCTE Level 3 Total Solar Irradiance Daily Means V002

Data.gov (United States)

National Aeronautics and Space Administration — The Total Solar Irradiance (TSI) Calibration Transfer Experiment (TCTE) data set TCTE3TSID contains daily averaged total solar irradiance (a.k.a solar constant) data...
An Adaptive Noise Cancellation System Based on Linear and Widely Linear Complex Valued Least Mean Square Algorithms for Removing Electrooculography Artifacts from Electroencephalography Signals

Directory of Open Access Journals (Sweden)

Engin Cemal MENGÜÇ

2018-03-01

Full Text Available In this study, an adaptive noise cancellation (ANC system based on linear and widely linear (WL complex valued least mean square (LMS algorithms is designed for removing electrooculography (EOG artifacts from electroencephalography (EEG signals. The real valued EOG and EEG signals (Fp1 and Fp2 given in dataset are primarily expressed as a complex valued signal in the complex domain. Then, using the proposed ANC system, the EOG artifacts are eliminated in the complex domain from the EEG signals. Expression of these signals in the complex domain allows us to remove EOG artifacts from two EEG channels simultaneously. Moreover, in this study, it has been shown that the complex valued EEG signal exhibits noncircular behavior, and in the case, the WL-CLMS algorithm enhances the performance of the ANC system compared to real-valued LMS and CLMS algorithms. Simulation results support the proposed approach.
Geoenvironmental profile of squares: north area of the city of Londrina-PR

Directory of Open Access Journals (Sweden)

Guilherme Silveira

2001-01-01

Full Text Available This article presents the concern to the quality and amount of the squares of the north area of the city of Londrina, state of Paraná. The square is a leisure, walk and rest place, besides favoring a closer contact of the population with the nature. The physical aspects of the furniture, presence and type of area of infantile and sporting recreation were analyzed, and also the identification and quantification of the species of trees. The results demonstrated absence of area of infantile recreation, 53% of the squares without furniture and sporting areas in 38% of the places. The amount of trees belonged to 340 individuals, divided in 35 species, with prevalence of 5 species that represents 64% of the total. Such results suggest the improvement of the amount and quality of the furniture, and a better distribution of the species of trees, giving preference for native species. The creation of a GIS, indicating the place of occurrence of the squares and its situation, is important because it facilitates the analysis of the green areas, as well as in the decisions for the urban development.
Computational logic with square rings of nanomagnets

Science.gov (United States)

Arava, Hanu; Derlet, Peter M.; Vijayakumar, Jaianth; Cui, Jizhai; Bingham, Nicholas S.; Kleibert, Armin; Heyderman, Laura J.

2018-06-01

Nanomagnets are a promising low-power alternative to traditional computing. However, the successful implementation of nanomagnets in logic gates has been hindered so far by a lack of reliability. Here, we present a novel design with dipolar-coupled nanomagnets arranged on a square lattice to (i) support transfer of information and (ii) perform logic operations. We introduce a thermal protocol, using thermally active nanomagnets as a means to perform computation. Within this scheme, the nanomagnets are initialized by a global magnetic field and thermally relax on raising the temperature with a resistive heater. We demonstrate error-free transfer of information in chains of up to 19 square rings and we show a high level of reliability with successful gate operations of ∼94% across more than 2000 logic gates. Finally, we present a functionally complete prototype NAND/NOR logic gate that could be implemented for advanced logic operations. Here we support our experiments with simulations of the thermally averaged output and determine the optimal gate parameters. Our approach provides a new pathway to a long standing problem concerning reliability in the use of nanomagnets for computation.
Some Theoretical Essences of Lithuania Squares Formation

Directory of Open Access Journals (Sweden)

Gintautas Tiškus

2016-04-01

Full Text Available In the Lithuanian acts of law and in the scientific literature there are no clear criteria and notions to define a square. The unbuilt city space places or the gaps between buildings are often defined as the squares, which do not have clear limits or destination. The mandatory attributes of the place which is called the square are indicated in the article, the notion of square is defined. The article deals with Lithuanian squares theme, analyses the differences between representation and representativeness. The article aims to indicate an influence of city environmental context and monument in the square on its function. The square is an independent element of city plan structure, but it is not an independent element of city spatial structure. The space and environment of the square are related to each other not only by physical, aesthetical relations, but as well as by causalities, which may be named as the essences of squares’ formation. The interdisciplinary discourse analysis method is applied in the article.
Latin Squares

Indian Academy of Sciences (India)

Admin

2012-09-07

Sep 7, 2012 ... must first talk of permutations and Latin squares. A permutation of a finite set of objects is a linear arrange- ment of ... with a special element 1 ... Of course, this has .... tion method to disprove Euler's conjecture for infinitely.
4He adsorbed in cylindrical silica nanopores: Effect of size on the single-atom mean kinetic energy

International Nuclear Information System (INIS)

Andreani, C.; Senesi, R.; Pantalei, C.

2007-01-01

This paper reports a study of the short-time dynamics of helium confined in silica nanopores (xerogel powder), with average pore diameters of 24 and 160 A. The longitudinal momentum distribution of helium adsorbed in xerogels has been determined via deep inelastic neutron scattering (DINS) measurements performed on the VESUVIO spectrometer at the ISIS spallation source. DINS measurements, in the attosecond time scale (i.e., 10 -16 -10 -15 s), were performed at a temperature of T=2.5 K and saturated vapor pressure conditions, with 95% pore volume filling. The average wave-vector transfer q was about 130 A -1 . For confined helium, significant changes in the values of the single-particle mean kinetic energies K > are found in the bulk phase. These are 32.6±8.7 K for the 24 A and 24.4±5.3 K for the 160 A pore diameters, remarkably higher than K >=16.2±0.4 K, the value of normal liquid 4 He at T=2.5 K and saturated vapor pressure conditions. The results are interpreted in terms of a model where 4 He atoms are arranged in concentric annuli along the cylindrical pore axis, with K > mainly dependent on the ratio between the atomic 'effective' diameter and the pore diameter. The number of solid layers close to pore surface is found to be strongly pore-size dependent with one single solid layer for 24 A diameter pore and three solid layers for 160 A diameter pore
The elastic buckling of super-graphene and super-square carbon nanotube networks

International Nuclear Information System (INIS)

Li Ying; Qiu Xinming; Yin Yajun; Yang Fan; Fan Qinshan

2010-01-01

The super-graphene (SG) and super-square (SS) carbon nanotube network are built by the straight single-walled carbon nanotubes and corresponding junctions. The elastic buckling behaviors of these carbon nanotube networks under different boundary conditions are explored through the molecular structural mechanics method. The following results are obtained: (a) The critical buckling forces of the SG and SS networks decrease as the side lengths or aspect ratios of the networks increase. The continuum plate theory could give good predictions to the buckling of the SS network but not the SG network with non-uniform buckling modes. (b) The carbon nanotube networks are more stable structures than the graphene structures with less carbon atoms.
Rate constant for the reaction of atomic oxygen with phosphine at 298 K

Science.gov (United States)

Stief, L. J.; Payne, W. A.; Nava, D. F.

1987-01-01

The rate constant for the reaction of atomic oxygen with phosphine has been measured at 298 K using flash photolysis combined with time-resolved detection of O(3P) via resonance fluorescence. Atomic oxygen was produced by flash photolysis of N2O or NO highly diluted in argon. The results were shown to be independent of (PH3), (O), total pressure and the source of O(3P). The mean value of all the experiments is k1 = (3.6 + or -0.8) x 10 to the -11th cu cm/s (1 sigma). Two previous measurements of k1 differed by more than an order of magnitude, and the results support the higher value obtained in a discharge flow-mass spectrometry study. A comparison with rate data for other atomic and free radical reactions with phosphine is presented, and the role of these reactions in the aeronomy or photochemistry of Jupiter and Saturn is briefly considered.

Influence of the least-squares phase on optical vortices in strongly scintillated beams

CSIR Research Space (South Africa)

Chen, M

2009-06-01

Full Text Available , the average total number of vortices is reduced further. However, the reduction becomes smaller for each succes- sive step. This indicates that the ability of getting rid of optical vortices by removing the least-squares phase becomes progressively less...
Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

International Nuclear Information System (INIS)

Rodriguez Roman, Susan; Barquero, M.

2000-01-01

Arsenic is an element that has been studied in the analysis of environmental samples for its toxicity showed in very low concentrations. The objective of this work is the validation of a method for the determination of total inorganic arsenic in drinking water. Through the spectrophotometric technique of atomic absorption an automatic system of flow injection for the generation of hydrides is used. The prereduction of Arsenic was made with potasium iodide 1,5% m/v and ascorbic acid 0.25% m/v dissolved in hydrochloric acid 3,7% m/v. The recuperation percentage of the method was 97 ± 3% in a dynamic range to 30 μg/L. The detection limit was 0,7 μg/L established over 0,5 mL of sample. The samples analyzed were found under the set limits of normative in Costa Rica of 10 μg/L. (author) [es
Quantum phases of low-dimensional ultra-cold atom systems

Science.gov (United States)

Mathey, Ludwig G.

2007-06-01

In this thesis we derive and explore the quantum phases of various types of ultracold atom systems, as well as their experimental signature. The technology of cooling, trapping and manipulating ultracold atoms has advanced in an amazing fashion during the last decade, which has led to the study of many-body effects of atomic ensembles. We first consider atomic mixtures in one dimension, which show a rich structure of phases, using a Luttinger liquid description. We then go on to consider how noise correlations in time-of-flight images of one-dimensional systems can be used to draw conclusions about the many-body state that they're in. Thirdly, we consider the quantum phases of Bose-Fermi mixtures in optical lattices, either square lattices or triangular lattices, using the powerful method of functional renormalization group analysis. Lastly, we study the phases of two-coupled quasi-superfluids in two dimensions, which shows unusual phases, and which could be used to realize the Kibble-Zurek mechanism, i.e. the generation of topological defects by ramping across a phase transition, first proposed in the context of an early universe scenario.
PENERAPAN METODE LEAST MEDIAN SQUARE-MINIMUM COVARIANCE DETERMINANT (LMS-MCD DALAM REGRESI KOMPONEN UTAMA

Directory of Open Access Journals (Sweden)

I PUTU EKA IRAWAN

2013-11-01

Full Text Available Principal Component Regression is a method to overcome multicollinearity techniques by combining principal component analysis with regression analysis. The calculation of classical principal component analysis is based on the regular covariance matrix. The covariance matrix is optimal if the data originated from a multivariate normal distribution, but is very sensitive to the presence of outliers. Alternatives are used to overcome this problem the method of Least Median Square-Minimum Covariance Determinant (LMS-MCD. The purpose of this research is to conduct a comparison between Principal Component Regression (RKU and Method of Least Median Square - Minimum Covariance Determinant (LMS-MCD in dealing with outliers. In this study, Method of Least Median Square - Minimum Covariance Determinant (LMS-MCD has a bias and mean square error (MSE is smaller than the parameter RKU. Based on the difference of parameter estimators, still have a test that has a difference of parameter estimators method LMS-MCD greater than RKU method.
On the role of structure-dynamic relationship in determining the excess entropy of mixing and chemical ordering in binary square-well liquid alloys

Science.gov (United States)

Lalneihpuii, R.; Shrivastava, Ruchi; Mishra, Raj Kumar

2018-05-01

Using statistical mechanical model with square-well (SW) interatomic potential within the frame work of mean spherical approximation, we determine the composition dependent microscopic correlation functions, interdiffusion coefficients, surface tension and chemical ordering in Ag-Cu melts. Further Dzugutov universal scaling law of normalized diffusion is verified with SW potential in binary mixtures. We find that the excess entropy scaling law is valid for SW binary melts. The partial and total structure factors in the attractive and repulsive regions of the interacting potential are evaluated and then Fourier transformed to get partial and total radial distribution functions. A good agreement between theoretical and experimental values for total structure factor and the reduced radial distribution function are observed, which consolidates our model calculations. The well-known Bhatia-Thornton correlation functions are also computed for Ag-Cu melts. The concentration-concentration correlations in the long wavelength limit in liquid Ag-Cu alloys have been analytically derived through the long wavelength limit of partial correlation functions and apply it to demonstrate the chemical ordering and interdiffusion coefficients in binary liquid alloys. We also investigate the concentration dependent viscosity coefficients and surface tension using the computed diffusion data in these alloys. Our computed results for structure, transport and surface properties of liquid Ag-Cu alloys obtained with square-well interatomic interaction are fully consistent with their corresponding experimental values.
Atomic structure of large angle grain boundaries determined by quantitative X-ray diffraction techniques

International Nuclear Information System (INIS)

Fitzsimmons, M.R.; Sass, S.L.

1988-01-01

Quantitative X-ray diffraction techniques have been used to determine the atomic structure of the Σ = 5 and 13 [001] twist boundaries in Au with a resolution of 0.09 Angstrom or better. The reciprocal lattices of these boundaries were mapped out using synchrotron radiation. The atomic structures were obtained by testing model structures against the intensity observations with a chi square analysis. The boundary structure were modeled using polyhedra, including octahedra, special configurations of tetrahedra and Archimedian anti-prisms, interwoven together by the boundary symmetry. The results of this work point to the possibility of obtaining general rules for grain boundary structure based on X-ray diffraction observations that give the atomic positions with high resolution
A Monte Carlo Investigation of the Box-Cox Model and a Nonlinear Least Squares Alternative.

OpenAIRE

Showalter, Mark H

1994-01-01

This paper reports a Monte Carlo study of the Box-Cox model and a nonlinear least squares alternative. Key results include the following: the transformation parameter in the Box-Cox model appears to be inconsistently estimated in the presence of conditional heteroskedasticity; the constant term in both the Box-Cox and the nonlinear least squares models is poorly estimated in small samples; conditional mean forecasts tend to underestimate their true value in the Box-Cox model when the transfor...
Quantum–classical correspondence in chaotic dynamics of laser-driven atoms

International Nuclear Information System (INIS)

Prants, S V

2017-01-01

This paper is a review article on some aspects of quantum–classical correspondence in chaotic dynamics of cold atoms interacting with a standing-wave laser field forming an optical lattice. The problem is treated from both (semi)classical and quantum points of view. In both approaches, the interaction of an atomic electic dipole with the laser field is treated quantum mechanically. Translational motion is described, at first, classically (atoms are considered to be point-like objects) and then quantum mechanically as a propagation of matter waves. Semiclassical equations of motion are shown to be chaotic in the sense of classical dynamical chaos. Point-like atoms in an absolutely deterministic and rigid optical lattice can move in a random-like manner demonstrating a chaotic walking with typical features of classical chaos. This behavior is explained by random-like ‘jumps’ of one of the atomic internal variable when atoms cross nodes of the standing wave and occurs in a specific range of the atom-field detuning. When treating atoms as matter waves, we show that they can make nonadiabatic transitions when crossing the standing-wave nodes. The point is that atomic wave packets split at each node in the same range of the atom-field detuning where the classical chaos occurs. The key point is that the squared amplitude of those semiclassical ‘jumps’ equal to the quantum Landau–Zener parameter which defines the probability of nonadiabatic transitions at the nodes. Nonadiabatic atomic wave packets are much more complicated compared to adiabatic ones and may be called chaotic in this sense. A few possible experiments to observe some manifestations of classical and quantum chaos with cold atoms in horizontal and vertical optical lattices are proposed and discussed. (paper)
The investigation of the light radiation caused polyethylene based materials deterioration by means of atomic force microscopy

International Nuclear Information System (INIS)

Sikora, A; Moroń, L; Wałecki, M; Kryla, P; Grabarek, A

2016-01-01

The impact of the environmental conditions on the materials used in various devices and constructions, in particular in electrotechnical applications, has an critical impact in terms of their reliability and utilization range in specific climatic conditions. Due to increasing utilitarian requirements, technological processes complexity and introducing new materials (for instance nanomaterials), advanced diagnostic techniques are desired. One of such techniques is atomic force microscopy (AFM), which allows to study the changes of the roughness and mechanical properties of the surface at the submicrometer scale, enabling the investigation of the degradation processes. In this work the deterioration of selected group of polyethylene based materials have been measured by means of AFM, as the samples were exposed to the simulated solar light and UV-C radiation. Such an analysis of the environmental conditions impact on the deterioration process using AFM methods for various versions of specific material was not presented before. (paper)
Mean excitation energies for molecular ions

DEFF Research Database (Denmark)

Jensen, Phillip W.K.; Sauer, Stephan P.A.; Oddershede, Jens

2017-01-01

The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...
Quantitative determination of glycyrrhizinic acid by square-wave

Directory of Open Access Journals (Sweden)

Aneta Dimitrovska

2003-06-01

Full Text Available Novel adsorptive stripping square-wave voltammetric method as well as a new high-pressure liquid chromatographic method for direct determination of glycyrrhizinic acid in dosage pharmaceutical preparation, used against virus infections, have been developed. Glycyrrhizinic acid is an electrochemically active compound, which undergoes irreversible reduction on a mercury electrode surface in an aqueous medium. Its redox properties were studied thoroughly by means of square-wave voltammetry, as one of the most advanced electroanalytical technique. The voltammetric response depends mainly on the pH of the medium, composition of the supporting electrolyte, as well as the parameters of the excitement signal. It was also observed that the voltammetric properties strongly depend on the accumulation time and potential, revealing significant adsorption of glycyrrhizinic acid onto the mercury electrode surface. Upon this feature, an adsorptive stripping voltammetric method for quantitative determination of glycyrrhizinic acid was developed. A simple, sensitive and precise reversed phase HPLC method with photodiode array UV detection has also been developed, mainly for comparison and conformation of the results obtained with the voltammetric method.
Fast atom diffraction for grazing scattering of Ne atoms from a LiF(0 0 1) surface

International Nuclear Information System (INIS)

Gravielle, M.S.; Schueller, A.; Winter, H.; Miraglia, J.E.

2011-01-01

Angular distributions of fast Ne atoms after grazing collisions with a LiF(0 0 1) surface under axial surface channeling conditions are experimentally and theoretically studied. We use the surface eikonal approximation to describe the quantum interference of scattered projectiles, while the atom-surface interaction is represented by means of a pairwise additive potential, including the polarization of the projectile atom. Experimental data serve as a benchmark to investigate the performance of the proposed potential model, analyzing the role played by the projectile polarization.
Fast atom diffraction for grazing scattering of Ne atoms from a LiF(0 0 1) surface

Energy Technology Data Exchange (ETDEWEB)

Gravielle, M.S., E-mail: msilvia@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Casilla de correo 67, sucursal 28 C1428EGA, Buenos Aires (Argentina); Departamento de Fisica, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Schueller, A.; Winter, H. [Institut fuer Physik, Humboldt Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin-Adlershof (Germany); Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Casilla de correo 67, sucursal 28 C1428EGA, Buenos Aires (Argentina); Departamento de Fisica, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

2011-06-01

Angular distributions of fast Ne atoms after grazing collisions with a LiF(0 0 1) surface under axial surface channeling conditions are experimentally and theoretically studied. We use the surface eikonal approximation to describe the quantum interference of scattered projectiles, while the atom-surface interaction is represented by means of a pairwise additive potential, including the polarization of the projectile atom. Experimental data serve as a benchmark to investigate the performance of the proposed potential model, analyzing the role played by the projectile polarization.
Calculation of high-order virial coefficients for the square-well potential.

Science.gov (United States)

Do, Hainam; Feng, Chao; Schultz, Andrew J; Kofke, David A; Wheatley, Richard J

2016-07-01

Accurate virial coefficients B_{N}(λ,ɛ) (where ɛ is the well depth) for the three-dimensional square-well and square-step potentials are calculated for orders N=5-9 and well widths λ=1.1-2.0 using a very fast recursive method. The efficiency of the algorithm is enhanced significantly by exploiting permutation symmetry and by storing integrands for reuse during the calculation. For N=9 the storage requirements become sufficiently large that a parallel algorithm is developed. The methodology is general and is applicable to other discrete potentials. The computed coefficients are precise even near the critical temperature, and thus open up possibilities for analysis of criticality of the system, which is currently not accessible by any other means.
Determination of total arsenic in fish by hydride-generation atomic absorption spectrometry: method validation, traceability and uncertainty evaluation

Science.gov (United States)

Nugraha, W. C.; Elishian, C.; Ketrin, R.

2017-03-01

Fish containing arsenic compound is one of the important indicators of arsenic contamination in water monitoring. The high level of arsenic in fish is due to absorption through food chain and accumulated in their habitat. Hydride generation (HG) coupled with atomic absorption spectrometric (AAS) detection is one of the most popular techniques employed for arsenic determination in a variety of matrices including fish. This study aimed to develop a method for the determination of total arsenic in fish by HG-AAS. The method for sample preparation from American of Analytical Chemistry (AOAC) Method 999.10-2005 was adopted for acid digestion using microwave digestion system and AOAC Method 986.15 - 2005 for dry ashing. The method was developed and validated using Certified Reference Material DORM 3 Fish Protein for trace metals for ensuring the accuracy and the traceability of the results. The sources of uncertainty of the method were also evaluated. By using the method, it was found that the total arsenic concentration in the fish was 45.6 ± 1.22 mg.Kg-1 with a coverage factor of equal to 2 at 95% of confidence level. Evaluation of uncertainty was highly influenced by the calibration curve. This result was also traceable to International Standard System through analysis of Certified Reference Material DORM 3 with 97.5% of recovery. In summary, it showed that method of preparation and HG-AAS technique for total arsenic determination in fish were valid and reliable.
Least-squares model-based halftoning

Science.gov (United States)

Pappas, Thrasyvoulos N.; Neuhoff, David L.

1992-08-01

A least-squares model-based approach to digital halftoning is proposed. It exploits both a printer model and a model for visual perception. It attempts to produce an 'optimal' halftoned reproduction, by minimizing the squared error between the response of the cascade of the printer and visual models to the binary image and the response of the visual model to the original gray-scale image. Conventional methods, such as clustered ordered dither, use the properties of the eye only implicitly, and resist printer distortions at the expense of spatial and gray-scale resolution. In previous work we showed that our printer model can be used to modify error diffusion to account for printer distortions. The modified error diffusion algorithm has better spatial and gray-scale resolution than conventional techniques, but produces some well known artifacts and asymmetries because it does not make use of an explicit eye model. Least-squares model-based halftoning uses explicit eye models and relies on printer models that predict distortions and exploit them to increase, rather than decrease, both spatial and gray-scale resolution. We have shown that the one-dimensional least-squares problem, in which each row or column of the image is halftoned independently, can be implemented with the Viterbi's algorithm. Unfortunately, no closed form solution can be found in two dimensions. The two-dimensional least squares solution is obtained by iterative techniques. Experiments show that least-squares model-based halftoning produces more gray levels and better spatial resolution than conventional techniques. We also show that the least- squares approach eliminates the problems associated with error diffusion. Model-based halftoning can be especially useful in transmission of high quality documents using high fidelity gray-scale image encoders. As we have shown, in such cases halftoning can be performed at the receiver, just before printing. Apart from coding efficiency, this approach
Information entropy properties of the atoms in the system of coupled Λ-type three-level atoms interacting with coherent field in Kerr medium

International Nuclear Information System (INIS)

Li Ke; Ling Weijun

2011-01-01

The information entropy properties of the atoms of coupled Λ-type three-level atoms interacting with coherent field are studied by means of quantum theory, and discussed the time evolutions of the information entropy of the atoms via the average photon number, initial state of the atoms, detuning, coupling constant between the atoms and the coefficient of Kerr medium. Numerical calculation results show that the time evolutions of the information entropy properties of the atoms strongly dependent on the initial state of the system and the average photon number. Detuning, coupling constant between the atoms and the Kerr coefficient still make influence on the information entropy of the atoms. (authors)
Economical Appraisal of Total Aflatoxin Level in the Poultry Feeds by Fourier Transform Infrared Spectroscopy

International Nuclear Information System (INIS)

Sherazai, S.T.H.; Shar, Z.; Iqbal, M.; Sumbal, G.A.

2013-01-01

Single-bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy has been used for the quantitative determination of total aflatoxins in the broiler poultry feed. An FTIR calibration spanning the range 1-70 micro g/L aflatoxin standards in (70:30, v/v) methanol-water solvent system based on partial least square (PLS) model, developed by relating mid IR region between 3755-950 cm/ sub -1/. The excellent coefficient of various (using 0.998) was achieved with 1.49 relative mean square error of calibration (RMSEC). Aflatoxins from each of eight poultry feeds was extracted and the determined by the widely used commercially available Enzyme-linked Immunosorbent Assay (ELISA) procedure and the SB-ATR/FTIR method. The SB-ATR/FTIR aflatoxins predictions were related to those determined by the ELISA method by linear regression, producing an R value of 0.989 and a SD of +- 2.80 micro g/L. The result of the study clearly indicated that FT-IR spectroscopy due to its rapidity and simplicity along with data manipulation by advance computer software could be effectively used for routine determination of aflatoxins present in the poultry feeds at very low level. (author)
MTS-MD of Biomolecules Steered with 3D-RISM-KH Mean Solvation Forces Accelerated with Generalized Solvation Force Extrapolation.

Science.gov (United States)

Omelyan, Igor; Kovalenko, Andriy

2015-04-14

We developed a generalized solvation force extrapolation (GSFE) approach to speed up multiple time step molecular dynamics (MTS-MD) of biomolecules steered with mean solvation forces obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model with the Kovalenko-Hirata closure). GSFE is based on a set of techniques including the non-Eckart-like transformation of coordinate space separately for each solute atom, extension of the force-coordinate pair basis set followed by selection of the best subset, balancing the normal equations by modified least-squares minimization of deviations, and incremental increase of outer time step in motion integration. Mean solvation forces acting on the biomolecule atoms in conformations at successive inner time steps are extrapolated using a relatively small number of best (closest) solute atomic coordinates and corresponding mean solvation forces obtained at previous outer time steps by converging the 3D-RISM-KH integral equations. The MTS-MD evolution steered with GSFE of 3D-RISM-KH mean solvation forces is efficiently stabilized with our optimized isokinetic Nosé-Hoover chain (OIN) thermostat. We validated the hybrid MTS-MD/OIN/GSFE/3D-RISM-KH integrator on solvated organic and biomolecules of different stiffness and complexity: asphaltene dimer in toluene solvent, hydrated alanine dipeptide, miniprotein 1L2Y, and protein G. The GSFE accuracy and the OIN efficiency allowed us to enlarge outer time steps up to huge values of 1-4 ps while accurately reproducing conformational properties. Quasidynamics steered with 3D-RISM-KH mean solvation forces achieves time scale compression of conformational changes coupled with solvent exchange, resulting in further significant acceleration of protein conformational sampling with respect to real time dynamics. Overall, this provided a 50- to 1000-fold effective speedup of conformational sampling for these systems, compared to conventional MD
Cooling and trapping neutral atoms with radiative forces

International Nuclear Information System (INIS)

Bagnato, V.S.; Castro, J.C.; Li, M.S.; Zilio, S.C.

1988-01-01

Techniques to slow and trap neutral atoms at high densities with radiative forces are discussed in this review articles. Among several methods of laser cooling, it is emphasized Zeeman Tuning of the electronic levels and frequency-sweeping techniques. Trapping of neutral atoms and recent results obtained in light and magnetic traps are discussed. Techniques to further cool atoms inside traps are presented and the future of laser cooling of neutral atoms by means of radiation pressure is discussed. (A.C.A.S.) [pt

Light forces on an indium atomic beam

International Nuclear Information System (INIS)

Kloeter, B.

2007-01-01

In this thesis it was studied, whether indium is a possible candidate for the nanostructuration respectively atomic lithography. For this known method for the generation and stabilization of the light necessary for the laser cooling had to be fitted to the special properties of indium. The spectroscopy of indium with the 451 nm and the 410 nm light yielded first hints that the formulae for the atom-light interaction for a two-level atom cannot be directly transferred to the indium atom. By means of the obtained parameters of the present experiment predictions for a possible Doppler cooling of the indium atomic beam were calculated. Furthermore the possibility for the direct deposition of indium on a substrate was studied
"First among Others? Cohen's ""d"" vs. Alternative Standardized Mean Group Difference Measures"

Directory of Open Access Journals (Sweden)

Sorel Cahan

2011-06-01

Full Text Available Standardized effect size measures typically employed in behavioral and social sciences research in the multi-group case (e.g., 2, f2 evaluate between-group variability in terms of either total or within-group variability, such as variance or standard deviation -' that is, measures of dispersion about the mean. In contrast, the definition of Cohen's d, the effect size measure typically computed in the two-group case, is incongruent due to a conceptual difference between the numerator -' which measures between-group variability by the intuitive and straightforward raw difference between the two group means -' and the denominator - which measures within-group variability in terms of the difference between all observations and the group mean (i.e., the pooled within-groups standard deviation, SW. Two congruent alternatives to d, in which the root square or absolute mean difference between all observation pairs is substituted for SW as the variability measure in the denominator of d, are suggested and their conceptual and statistical advantages and disadvantages are discussed.
Laser Cooling and Trapping of Atoms and Particles

Science.gov (United States)

1992-01-16

magnitude. The creation of an atom trampoline , where cold atoms were dropped onto a evanescent wave of light extending out of a totally internally reflected...Staff, Electromagnetic Phenomena Research Bell Laboratories, Murray Hill, 1978-1983 Head , Quantum Electronics Research Department AT&T Bell
Determination of daily intake of elements from Philippine total diet samples using inductively coupled plasma-atomic emission spectrometry

International Nuclear Information System (INIS)

Leon, G.C. de; Shiraishi, K.; Kawamura, H.; Igaraishi, Y.; Palattao, M.V.; Azanon, E.M.

1990-10-01

Total diet samples were analyzed for major elements (Na, K, Ca, Mg, P) and some minor trace elements (Fe, Zn, Mn, Al, Sr, Cu, Ba, Yt) using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Samples analyzed were classified into sex and age groups. Results for some elements (Na, K, Mg, Zn, Cu, Mn) were compared with values from Bataan dietary survey calculated using the Philippine composition table. Exceot for Na, analytical results were similar to calculated values. Analytical results for Ca and Fe were also compared with the values from Food and Nutrition Research Institute. In general, values obtained in the study were lower than the FNRI values. Comparison of the analytical and calculated results with the Japanese and ICRP data showed that Philippine values were lower than foreign values. (Auth.). 22 refs., 9 tabs
Modular injector integrated linear apparatus with motion profile optimization for spatial atomic layer deposition

Science.gov (United States)

Wang, Xiaolei; Li, Yun; Lin, Jilong; Shan, Bin; Chen, Rong

2017-11-01

A spatial atomic layer deposition apparatus integrated with a modular injector and a linear motor has been designed. It consists of four parts: a precursor delivery manifold, a modular injector, a reaction zone, and a driving unit. An injector with multi-layer structured channels is designed to help improve precursor distribution homogeneity. During the back and forth movement of the substrate at high speed, the inertial impact caused by jerk and sudden changes of acceleration will degrade the film deposition quality. Such residual vibration caused by inertial impact will aggravate the fluctuation of the gap distance between the injector and the substrate in the deposition process. Thus, an S-curve motion profile is implemented to reduce the large inertial impact, and the maximum position error could be reduced by 84%. The microstructure of the film under the S-curve motion profile shows smaller root-mean-square and scanning voltage amplitude under an atomic force microscope, which verifies the effectiveness of the S-curve motion profile in reducing the residual vibration and stabilizing the gap distance between the injector and the substrate. The film deposition rate could reach 100 nm/min while maintaining good uniformity without obvious periodic patterns on the surface.
Magnetic trapping of cold bromine atoms.

Science.gov (United States)

Rennick, C J; Lam, J; Doherty, W G; Softley, T P

2014-01-17

Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.
Stereological quantification of tumor volume, mean nuclear volume and total number of melanoma cells correlated with morbidity and mortality

DEFF Research Database (Denmark)

Bønnelykke-Behrndtz, Marie Louise; Sørensen, Flemming Brandt; Damsgaard, Tine Engberg

2008-01-01

potential indicators of prognosis. Sixty patients who underwent surgery at the Department of Plastic Surgery, Aarhus University Hospital, from 1991 to 1994 were included in the study. Total tumor volume was estimated by the Cavalieri technique, total number of tumor cells by the optical dissector principle...... showed a significant impact on both disease-free survival (p=0.001) and mortality (p=0.009). In conclusion, tumor volume and total number of cancer cells were highly reproducible but did not add additional, independent prognostic information regarding the study population.......Stereological quantification of tumor volume, total number of tumor cells and mean nuclear volume provides unbiased data, regardless of the three-dimensional shape of the melanocytic lesion. The aim of the present study was to investigate whether these variables are reproducible and may represent...
Least-squares methods for identifying biochemical regulatory networks from noisy measurements

Directory of Open Access Journals (Sweden)

Heslop-Harrison Pat

2007-01-01

Full Text Available Abstract Background We consider the problem of identifying the dynamic interactions in biochemical networks from noisy experimental data. Typically, approaches for solving this problem make use of an estimation algorithm such as the well-known linear Least-Squares (LS estimation technique. We demonstrate that when time-series measurements are corrupted by white noise and/or drift noise, more accurate and reliable identification of network interactions can be achieved by employing an estimation algorithm known as Constrained Total Least Squares (CTLS. The Total Least Squares (TLS technique is a generalised least squares method to solve an overdetermined set of equations whose coefficients are noisy. The CTLS is a natural extension of TLS to the case where the noise components of the coefficients are correlated, as is usually the case with time-series measurements of concentrations and expression profiles in gene networks. Results The superior performance of the CTLS method in identifying network interactions is demonstrated on three examples: a genetic network containing four genes, a network describing p53 activity and mdm2 messenger RNA interactions, and a recently proposed kinetic model for interleukin (IL-6 and (IL-12b messenger RNA expression as a function of ATF3 and NF-κB promoter binding. For the first example, the CTLS significantly reduces the errors in the estimation of the Jacobian for the gene network. For the second, the CTLS reduces the errors from the measurements that are corrupted by white noise and the effect of neglected kinetics. For the third, it allows the correct identification, from noisy data, of the negative regulation of (IL-6 and (IL-12b by ATF3. Conclusion The significant improvements in performance demonstrated by the CTLS method under the wide range of conditions tested here, including different levels and types of measurement noise and different numbers of data points, suggests that its application will enable
Breakup of relativistic π+π- atoms in matter

International Nuclear Information System (INIS)

Afanasyev, L.G.; Tarasov, A.V.

1996-01-01

The relativistic motion of atoms formed by π+ and π- mesons in matter is considered. Exact analytic expressions for the form factors of hydrogenlike atoms for discrete-discrete transitions are obtained in a form convenient for numerical calculations. The total and transition cross sections for the interaction of π+π- atoms with matter are calculated in the Born approximation. The evolution of atomic-state populations is treated in terms of kinetic equations. The method of calculation makes it possible to obtain the populations of discrete atomic states, as well as the probability of transitions to the continuous spectrum (ionization). The proposed method yields the first experimental estimate of the lifetime of the π+π- atom
Positronium-alkali atom scattering at medium energies

International Nuclear Information System (INIS)

Chakraborty, Ajoy; Basu, Arindam; Sarkar, Nirmal K; Sinha, Prabal K

2004-01-01

We investigate the scattering of orthopositronium (o-Ps) atom off different atomic alkali targets (Na to Cs) at low and medium energies (up to 120 eV). Projectile-elastic and target-elastic close-coupling models have been employed to investigate the systems in addition to the static-exchange model. Elastic, excitation and total cross sections have been reported for all four systems. The magnitude of the alkali excitation cross section increases with increasing atomic number of the target atom while the position of the peak value shifts towards lower incident energies. The magnitudes of the Ps excitation and ionization cross sections increase steadily with atomic number with no change in the peak position. The reported results show regular behaviour with increasing atomic number of the target atom. Scattering parameters for the Ps-Rb and Ps-Cs systems are being reported for the first time
Atomic physics research with synchrotron radiation

International Nuclear Information System (INIS)

Crasemann, B.; Wuilleumier, F.

1985-01-01

This chapter discusses applications of synchrotron light in atomic and molecular physics. Use of the radiation from storage rings has expanded and lent access to new areas of absorption and photoemission spectroscopy and scattering experiments. Techniques applied in connection with synchrotron radiation are discussed including absorption spectroscopy, photoelectron spectroscopy, fluorescence spectroscopy and X-ray scattering. Problem areas that are being studied by the techniques mentioned above are discussed. Synchrotron radiation has provided the means for measuring the threshold-excitation and interference effects that signal the breakdown of the two-step model of atomic excitation/deexcitation. Synchrotron radiation provides more means of excited-state photoionization measurements
The coherence and spectra of a Bose condensate generated by an atomic laser

International Nuclear Information System (INIS)

Kozlovskii, A.V.

2003-01-01

The first-order coherence dynamics of a Bose condensate generated by a cw atomic laser with evaporative cooling is analyzed. For the atomic-laser multimode model, the coherence functions and atomic field spectra are calculated by the master equation technique. Elastic collisions in the trapped atomic gas lead to significant broadening of the atomic laser line, a shift of its center, and a multi peak structure of the spectra. The oscillatory time dynamics of the atomic-field coherence function is studied. For the atomic laser, the free phase diffusion of the field typical of optical lasers, and characterized by monotonically decreasing mean field with a constant mean phase, is absent due to elastic collisions
Serum TSH, thyroglobulin, and thyroidal disorders in atomic bomb survivors exposed in youth: 30-year follow-up study

International Nuclear Information System (INIS)

Morimoto, I.; Yoshimoto, Y.; Sato, K.; Hamilton, H.B.; Kawamoto, S.; Izumi, M.; Nagataki, S.

1987-01-01

Follow-up examinations to determine the frequency of thyroidal disorders were conducted by the Radiation Effects Research Foundation (RERF) on individuals in Hiroshima and Nagasaki who were less than 20 yr of age at the time of exposure to the atomic bomb. Concentrations of serum thyroid stimulating hormone (TSH), thyroglobulin (TG), and anti-TG antibody 30 yr after exposure were also determined. Nontoxic uninodular goiter was found in 13 cases of the 100 + rad exposed group (n = 477) and in three cases of the nonexposed group (n = 501). The prevalence in the 100+ rad exposed group was significantly higher (chi-squared = 6.584, p less than 0.01). Thyroid cancer was found in eight exposed cases, all of whom were in the 100+ rad group, and the prevalence was significantly greater (chi-squared = 7.919, p less than 0.01). Regardless of the presence or absence of thyroid disorders, serum TSH and TG levels were not statistically different between the 100 rad + exposed and nonexposed groups. Although hypothyroidism was found in 23 of the total cases, there was no correlation between its development and exposure to ionizing irradiation
PELINSCA, Elastic Scattering and Total Cross-Sections and Polarization by Hauser-Feshbach

International Nuclear Information System (INIS)

Engelbrecht, C.A.; Fiedeldey, H.; Tepel, J.W.

1979-01-01

1 - Nature of the physical problem solved: Calculates differential and total Cross sections as well as polarization for nuclear elastic scattering of spin 0 or spin 1/2 particles. Calculates Cross sections (differential and total) and decay gamma ray angular correlation for inelastic processes by means of standard Hauser-Feshbach (HF) theory or with modified HF theory including width fluctuation corrections. In elastic scattering optical model parameters may be optimized in a least squares procedure involving experimental measurements. 2 - Method of solution: Schroedinger equation for complex potentials is solved according to Fox-Goodwin method of numerical integration. Coulomb wave functions are calculated by using recurrence relations depending on range of Coulomb and energy parameters. Least squares fits are made using parameter grid and direction of steepest descent. Statistical model calculations are made using closed mathematical expressions. 3 - Restrictions on the complexity of the problem: Elastic scattering calculations limited to spin 0 or spin 1/2 particles. Number of partial waves limited to 51. Statistical model calculations on targets with spin less or equal to 5 and with partial waves up to l=6. Not suitable for heavy-ion Hauser- Feshbach calculations without first removing dimensional limitations. Program handles up to 3 reaction types simultaneously, e.g. (p,p), (p,n) and (p,alpha), each reaction channel having up to 33 final nuclear states
Application of fourier-transform infrared (ft-ir) spectroscopy for determination of total phenolics of freeze dried lemon juices

International Nuclear Information System (INIS)

Sherazi, S.T.H.; Bhutto, A.A.; Mehesar, S.A.

2017-01-01

A cost effective and environmentally safe analytical method for rapid assessment of total phenolic content (TPC) in freeze dried lemon juice samples was developed using transmission Fourier-transform infrared spectroscopy (FT-IR) in conjunction with chemometric techniques. Two types of calibrations i.e. simple Beer's law and partial least square (PLS) were applied to investigate most accurate calibration model based on region from1420 to 1330 cm-1. The better analytical performance was obtained by PLS technique coefficient of determination (R2), root mean square error of calibration (RMSEC) with the value of 0.999 and 0.00864, respectively. The results of TPC in freeze dried lemon juice samples obtained by transmission FT-IR were compared with TPC observed by Folin-Ciocalteu (FC) assay and found to be comparable. Outcomes of the present study indicate that transmission FT-IR spectroscopic approach could be used as an alternative approach in place of Folin-Ciocalteu (FC) assay which is expensive and time-consuming conventional chemical methods for determination of the total phenolic content of lemon fruits. (author)
Total water, phosphorus relaxation and inter-atomic organic to inorganic interface are new determinants of trabecular bone integrity.

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Ratan Kumar Rai

Full Text Available Bone is the living composite biomaterial having unique structural property. Presently, there is a considerable gap in our understanding of bone structure and composition in the native state, particularly with respect to the trabecular bone, which is metabolically more active than cortical bones, and is readily lost in post-menopausal osteoporosis. We used solid-state nuclear magnetic resonance (NMR to compare trabecular bone structure and composition in the native state between normal, bone loss and bone restoration conditions in rat. Trabecular osteopenia was induced by lactation as well as prolonged estrogen deficiency (bilateral ovariectomy, Ovx. Ovx rats with established osteopenia were administered with PTH (parathyroid hormone, trabecular restoration group, and restoration was allowed to become comparable to sham Ovx (control group using bone mineral density (BMD and µCT determinants. We used a technique combining (1H NMR spectroscopy with (31P and (13C to measure various NMR parameters described below. Our results revealed that trabecular bones had diminished total water content, inorganic phosphorus NMR relaxation time (T1 and space between the collagen and inorganic phosphorus in the osteopenic groups compared to control, and these changes were significantly reversed in the bone restoration group. Remarkably, bound water was decreased in both osteopenic and bone restoration groups compared to control. Total water and T1 correlated strongly with trabecular bone density, volume, thickness, connectivity, spacing and resistance to compression. Bound water did not correlate with any of the microarchitectural and compression parameters. We conclude that total water, T1 and atomic space between the crystal and organic surface are altered in the trabecular bones of osteopenic rats, and PTH reverses these parameters. Furthermore, from these data, it appears that total water and T1 could serve as trabecular surrogates of micro-architecture and
From Square Dance to Mathematics

Science.gov (United States)

Bremer, Zoe

2010-01-01

In this article, the author suggests a cross-curricular idea that can link with PE, dance, music and history. Teacher David Schmitz, a maths teacher in Illinois who was also a square dance caller, had developed a maths course that used the standard square dance syllabus to teach mathematical principles. He presents an intensive, two-week course…
Lagrange’s Four-Square Theorem

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Watase Yasushige

2015-02-01

Full Text Available This article provides a formalized proof of the so-called “the four-square theorem”, namely any natural number can be expressed by a sum of four squares, which was proved by Lagrange in 1770. An informal proof of the theorem can be found in the number theory literature, e.g. in [14], [1] or [23].
Interpretation of atom probe tomography data for the intermetallic TiAl+Nb by means of field evaporation simulation

KAUST Repository

Boll, Torben

2013-01-01

In this paper simulations of the field evaporation process during field ion microscopy (FIM) and atom probe tomography (APT) are presented and compared with experimental data. The Müller-Schottky-model [1] was extended to include the local atomic arrangement on the evaporation process of atoms. This arrangement was described by the sum of the next-neighbor-binding-energies, which differ for an atom of type A, depending on how many A-A, B-B or A-B bonds are present. Thus simulations of APT-data of intermetallic phases become feasible. In this study simulations of L10-TiAl with additions of Nb are compared with experimental data. Certain artifacts, which appear for experimental data are treated as well. © 2012 Elsevier B.V.
The electrostatic atomization of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Kelly, A J

1984-06-01

Exploitation of the unique and potentially beneficial characteristics of electrostatic atomization in combustion systems has foundered upon the inability of two element, diode devices to operate at flow rates that are larger than a fraction of a millilitre per second. This restriction has been attributed to the high innate electrical resistivity of hydrocarbon fuels. A discussion of proposed electrostatic fuel atomizers and their limitations is presented from the vantage of a recently developed theory of electrostatic spraying. Comparison of theory and experiment reveals the existence of a 'constant of spraying' and the presence of an operational regime in which low charge density droplet development is possible. Operation with hydrocarbons in this regime occurs when the mean droplet size is greater than or equal to 10 ..mu..m and fluid viscosity is below about 250 cp. The resulting spray has a mean droplet size that is functionally dependent only upon the free charge density level of the fluid. Consequently there is no theoretical impediment to the attainment of high flow rate electrostatic atomization with fluids of arbitrary conductivity. Implementation is achieved by a general class of electrostatic spray devices which employ direct charge injection. The Spray Triode, a submerged field-emission electron gun, represents a particularly simple member of this new class of atomizer. Among the Spray Triode operational characteristics to be discussed is insensitivity to spray fluid properties and flow rate.

An improved partial least-squares regression method for Raman spectroscopy

Science.gov (United States)

Momenpour Tehran Monfared, Ali; Anis, Hanan

2017-10-01

It is known that the performance of partial least-squares (PLS) regression analysis can be improved using the backward variable selection method (BVSPLS). In this paper, we further improve the BVSPLS based on a novel selection mechanism. The proposed method is based on sorting the weighted regression coefficients, and then the importance of each variable of the sorted list is evaluated using root mean square errors of prediction (RMSEP) criterion in each iteration step. Our Improved BVSPLS (IBVSPLS) method has been applied to leukemia and heparin data sets and led to an improvement in limit of detection of Raman biosensing ranged from 10% to 43% compared to PLS. Our IBVSPLS was also compared to the jack-knifing (simpler) and Genetic Algorithm (more complex) methods. Our method was consistently better than the jack-knifing method and showed either a similar or a better performance compared to the genetic algorithm.
Model of directed lines for square ice with second-neighbor and third-neighbor interactions

Science.gov (United States)

Kirov, Mikhail V.

2018-02-01

The investigation of the properties of nanoconfined systems is one of the most rapidly developing scientific fields. Recently it has been established that water monolayer between two graphene sheets forms square ice. Because of the energetic disadvantage, in the structure of the square ice there are no longitudinally arranged molecules. The result is that the structure is formed by unidirectional straight-lines of hydrogen bonds only. A simple but accurate discrete model of square ice with second-neighbor and third-neighbor interactions is proposed. According to this model, the ground state includes all configurations which do not contain three neighboring unidirectional chains of hydrogen bonds. Each triplet increases the energy by the same value. This new model differs from an analogous model with long-range interactions where in the ground state all neighboring chains are antiparallel. The new model is suitable for the corresponding system of point electric (and magnetic) dipoles on the square lattice. It allows separately estimating the different contributions to the total binding energy and helps to understand the properties of infinite monolayers and finite nanostructures. Calculations of the binding energy for square ice and for point dipole system are performed using the packages TINKER and LAMMPS.
The mean ''size'' of polyatomic boxes for a binary mixing

International Nuclear Information System (INIS)

Mejdani, R.

1991-06-01

In the present work we have studied in detail the problem of the mean ''size'' of mixing of chain-propagating atoms and chain-terminating atoms on a one-dimensional lattice, with respect to the temperature and the interaction constants. Some comparisons of the average chain length of a symmetric system to that of an asymmetric one allows us to state that the asymmetry of bonds play an important role in determining the mean chain length or the mean ''size'' of boxes. (author). 4 refs, 6 figs
Discerning urban spiritualities: Tahrir Square, Occupy Wall Street and the idols of global market capitalism

Directory of Open Access Journals (Sweden)

Calvyn C. du Toit

2015-03-01

Full Text Available Discernment might be said to be a process of searching for meaning in the light of an (un articulated Absolute. This search takes place in the tension between the private and public spheres of life, mostly mitigated by a community. Intermediate communities, such as churches or social movements, construct symbolic spirituality systems for its adherers to search for meaning in the light of an (unarticulated Absolute. The urban events of Occupy Wall Street and Tahrir Square also step into the tension between the public and private spheres of life, creating a (temporary symbolic spirituality system for its adherers. These events were attempts to construct alternatives to the meta-narrative of global market capitalism. As events attempting to symbolise an urban spirituality, Tahrir Square and Occupy Wall Street dissipated rapidly, effecting rather little change at the heart of global market capitalism. This article theorises a possible reason for these urban spiritualities� dissipation, namely an overlap with global market capitalism�s idols of instant gratification and technology.Interdisciplinary Implications: Viewing Occupy Walls Street and Tahrir Square as symbolic systems of spirituality further strengthens theological urban discourse whilst adding weight to viewing mass movements as spiritualities attempting discernment.
The inverse square law of gravitation

International Nuclear Information System (INIS)

Cook, A.H.

1987-01-01

The inverse square law of gravitation is very well established over the distances of celestial mechanics, while in electrostatics the law has been shown to be followed to very high precision. However, it is only within the last century that any laboratory experiments have been made to test the inverse square law for gravitation, and all but one has been carried out in the last ten years. At the same time, there has been considerable interest in the possibility of deviations from the inverse square law, either because of a possible bearing on unified theories of forces, including gravitation or, most recently, because of a possible additional fifth force of nature. In this article the various lines of evidence for the inverse square law are summarized, with emphasis upon the recent laboratory experiments. (author)
On two distinct Reynolds number regimes of a turbulent square jet

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Minyi Xu

2015-05-01

Full Text Available The effects of Reynolds number on both large-scale and small-scale turbulence properties are investigated in a square jet issuing from a square pipe. The detailed velocity fields were measured at five different exit Reynolds numbers of 8×103≤Re≤5×104. It is found that both large-scale properties (e.g., rates of mean velocity decay and spread and small-scale properties (e.g., the dimensionless dissipation rate constant A=εL/〈u2〉3/2 are dependent on Re for Re≤3×104 or Reλ≤190, but virtually become Re-independent with increasing Re or Reλ. In addition, for Reλ>190, the value of A=εL/〈u2〉3/2 in the present square jet converges to 0.5, which is consistent with the observation in direct numerical simulations of box turbulence, but lower than that in circular jet, plate wake flows, and grid turbulence. The discrepancies in critical Reynolds number and A=εL/〈u2〉3/2 among different turbulent flows most likely result from the flow type and initial conditions.
Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

Science.gov (United States)

Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

2013-01-01

Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.
Identification of Combined Power Quality Disturbances Using Singular Value Decomposition (SVD and Total Least Squares-Estimation of Signal Parameters via Rotational Invariance Techniques (TLS-ESPRIT

Directory of Open Access Journals (Sweden)

Huaishuo Xiao

2017-11-01

Full Text Available In order to identify various kinds of combined power quality disturbances, the singular value decomposition (SVD and the improved total least squares-estimation of signal parameters via rotational invariance techniques (TLS-ESPRIT are combined as the basis of disturbance identification in this paper. SVD is applied to identify the catastrophe points of disturbance intervals, based on which the disturbance intervals are segmented. Then the improved TLS-ESPRIT optimized by singular value norm method is used to analyze each data segment, and extract the amplitude, frequency, attenuation coefficient and initial phase of various kinds of disturbances. Multi-group combined disturbance test signals are constructed by MATLAB and the proposed method is also tested by the measured data of IEEE Power and Energy Society (PES Database. The test results show that the new method proposed has a relatively higher accuracy than conventional TLS-ESPRIT, which could be used in the identification of measured data.
Positive solution of non-square fully Fuzzy linear system of equation in general form using least square method

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Reza Ezzati

2014-08-01

Full Text Available In this paper, we propose the least square method for computing the positive solution of a non-square fully fuzzy linear system. To this end, we use Kaffman' arithmetic operations on fuzzy numbers \\cite{17}. Here, considered existence of exact solution using pseudoinverse, if they are not satisfy in positive solution condition, we will compute fuzzy vector core and then we will obtain right and left spreads of positive fuzzy vector by introducing constrained least squares problem. Using our proposed method, non-square fully fuzzy linear system of equations always has a solution. Finally, we illustrate the efficiency of proposed method by solving some numerical examples.
Mathematical Construction of Magic Squares Utilizing Base-N Arithmetic

Science.gov (United States)

O'Brien, Thomas D.

2006-01-01

Magic squares have been of interest as a source of recreation for over 4,500 years. A magic square consists of a square array of n[squared] positive and distinct integers arranged so that the sum of any column, row, or main diagonal is the same. In particular, an array of consecutive integers from 1 to n[squared] forming an nxn magic square is…
BIOMECHANICS. Why the seahorse tail is square.

Science.gov (United States)

Porter, Michael M; Adriaens, Dominique; Hatton, Ross L; Meyers, Marc A; McKittrick, Joanna

2015-07-03

Whereas the predominant shapes of most animal tails are cylindrical, seahorse tails are square prisms. Seahorses use their tails as flexible grasping appendages, in spite of a rigid bony armor that fully encases their bodies. We explore the mechanics of two three-dimensional-printed models that mimic either the natural (square prism) or hypothetical (cylindrical) architecture of a seahorse tail to uncover whether or not the square geometry provides any functional advantages. Our results show that the square prism is more resilient when crushed and provides a mechanism for preserving articulatory organization upon extensive bending and twisting, as compared with its cylindrical counterpart. Thus, the square architecture is better than the circular one in the context of two integrated functions: grasping ability and crushing resistance. Copyright © 2015, American Association for the Advancement of Science.
Analysis of a single-atom dipole trap

International Nuclear Information System (INIS)

Weber, Markus; Volz, Juergen; Saucke, Karen; Kurtsiefer, Christian; Weinfurter, Harald

2006-01-01

We describe a simple experimental technique which allows us to store a single 87 Rb atom in an optical dipole trap. Due to light-induced two-body collisions during the loading stage of the trap the maximum number of captured atoms is locked to one. This collisional blockade effect is confirmed by the observation of photon antibunching in the detected fluorescence light. The spectral properties of single photons emitted by the atom were studied with a narrow-band scanning cavity. We find that the atomic fluorescence spectrum is dominated by the spectral width of the exciting laser light field. In addition we observe a spectral broadening of the atomic fluorescence light due to the Doppler effect. This allows us to determine the mean kinetic energy of the trapped atom corresponding to a temperature of 105 μK. This simple single-atom trap is the key element for the generation of atom-photon entanglement required for future applications in quantum communication and a first loophole-free test of Bell's inequality
Unifying the crystallization behavior of hexagonal and square crystals with the phase-field-crystal model

International Nuclear Information System (INIS)

Yang Tao; Chen Zheng; Zhang Jing; Wang Yongxin; Lu Yanli

2016-01-01

By employing the phase-field-crystal models, the atomic crystallization process of hexagonal and square crystals is investigated with the emphasis on the growth mechanism and morphological change. A unified regime describing the crystallization behavior of both crystals is obtained with the thermodynamic driving force varying. By increasing the driving force, both crystals (in the steady-state) transform from a faceted polygon to an apex-bulged polygon, and then into a symmetric dendrite. For the faceted polygon, the interface advances by a layer-by-layer (LL) mode while for the apex-bulged polygonal and the dendritic crystals, it first adopts the LL mode and then transits into the multi-layer (ML) mode in the later stage. In particular, a shift of the nucleation sites from the face center to the area around the crystal tips is detected in the early growth stage of both crystals and is rationalized in terms of the relation between the crystal size and the driving force distribution. Finally, a parameter characterizing the complex shape change of square crystal is introduced. (paper)
Classification of networks of automata by dynamical mean field theory

International Nuclear Information System (INIS)

Burda, Z.; Jurkiewicz, J.; Flyvbjerg, H.

1990-01-01

Dynamical mean field theory is used to classify the 2 24 =65,536 different networks of binary automata on a square lattice with nearest neighbour interactions. Application of mean field theory gives 700 different mean field classes, which fall in seven classes of different asymptotic dynamics characterized by fixed points and two-cycles. (orig.)
Temperature dependence of knocking-out cross sections of a bound atom from the lattice site

International Nuclear Information System (INIS)

Zhdanov, S.K.; Pletnev, V.V.

1981-01-01

The total cross section of atom knocking-out from the lattice site is calculated with the atom binding in the lattice site taken into account. The intermediate case of atom being preads over the bottom of a spherical potential well is considered (the case of intermediate temperatures). Thus the target temperature parameter enters the equation for the total cross section of atom knocking-out
Atom-surface potentials and atom interferometry

International Nuclear Information System (INIS)

Babb, J.F.

1998-01-01

Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)
Atomic and molecular data for radiotherapy

International Nuclear Information System (INIS)

1989-05-01

An Advisory Group Meeting devoted solely to review the atomic and molecular data needed for radiotherapy was held in Vienna from 13 to 16 June 1988. The following items as related to the atoms and molecules of human tissues were reviewed: Cross sections differential in energy loss for electrons and other charged particles. Secondary electron spectra, or differential ionization cross sections. Total cross sections for ionization and excitation. Subexcitation electrons. Cross sections for charged-particle collisions in condensed matter. Stopping power for low-energy electrons and ions. Initial yields of atomic and molecular ions and their excited states and electron degradation spectra. Rapid conversion of these initial ions and their excited states through thermal collisions with other atoms and molecules. Track-structure quantities. Other relevant data. Refs, figs and tabs
Bremsstrahlung in atom-atom collisions

International Nuclear Information System (INIS)

Amus'ya, M.Y.; Kuchiev, M.Y.; Solov'ev, A.V.

1985-01-01

It is shown that in the collision of a fast atom with a target atom when the frequencies are on the order of the potentials or higher, there arises bremsstrahlung comparable in intensity with the bremsstrahlung emitted by an electron with the same velocity in the field of the target atom. The mechanism by which bremsstrahlung is produced in atom-atom collisions is elucidated. Results of specific calculations of the bremsstrahlung spectra are given for α particles and helium atoms colliding with xenon
Preferential states of rotating turbulent flows in a square container with a step topography

NARCIS (Netherlands)

Tenreiro, M.; Trieling, R.R.; Zavala Sansón, L.; Heijst, van G.J.F.

2013-01-01

The self-organization of confined, quasi-two-dimensional turbulent flows in a rotating square container with a step-like topography is investigated by means of laboratory experiments and numerical simulations based on a rigid lid, shallow-water formulation. The domain is divided by a bottom
Non-Asymptotic Confidence Sets for Circular Means

Directory of Open Access Journals (Sweden)

Thomas Hotz

2016-10-01

Full Text Available The mean of data on the unit circle is defined as the minimizer of the average squared Euclidean distance to the data. Based on Hoeffding’s mass concentration inequalities, non-asymptotic confidence sets for circular means are constructed which are universal in the sense that they require no distributional assumptions. These are then compared with asymptotic confidence sets in simulations and for a real data set.

Total reflection coefficients of low-energy photons presented as universal functions

Directory of Open Access Journals (Sweden)

Ljubenov Vladan

2010-01-01

Full Text Available The possibility of expressing the total particle and energy reflection coefficients of low-energy photons in the form of universal functions valid for different shielding materials is investigated in this paper. The analysis is based on the results of Monte Carlo simulations of photon reflection by using MCNP, FOTELP, and PENELOPE codes. The normal incidence of the narrow monoenergetic photon beam of the unit intensity and of initial energies from 20 keV up to 100 keV is considered, and particle and energy reflection coefficients from the plane homogenous targets of water, aluminum, and iron are determined and compared. The representations of albedo coefficients on the initial photon energy, on the probability of large-angle photon scattering, and on the mean number of photon scatterings are examined. It is found out that only the rescaled albedo coefficients dependent on the mean number of photon scatterings have the form of universal functions and these functions are determined by applying the least square method.
Positron interactions with water–total elastic, total inelastic, and elastic differential cross section measurements

International Nuclear Information System (INIS)

Tattersall, Wade; Chiari, Luca; Machacek, J. R.; Anderson, Emma; Sullivan, James P.; White, Ron D.; Brunger, M. J.; Buckman, Stephen J.; Garcia, Gustavo; Blanco, Francisco

2014-01-01

Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions
Nuclear structure of light thallium isotopes as deduced from laser spectroscopy on a fast atom beam

International Nuclear Information System (INIS)

Bounds, J.A.

1985-08-01

After optimizing the system by experiments on /sup 201,203,205/Tl, the neutron-deficient isotopes 189-193 Tl have been studied using the collinear fast atom beam laser spectroscopy system at UNISOR on-line to the Holifield Heavy Ion Research Facility. A sensitive system for the measurements was developed since the light isotopes were available in mass-separated beams of only 7 x 10 4 to 4 x 10 5 atoms per second. By laser excitation of the 535 nm atomic transitions of atoms in the beam, the 6s 2 7s 2 S/sub 1/2/ and 6s 2 6s 2 P/sub 3/2/ hyperfine structures were measured, as were the isotope shifts of the 535 nm transitions. From these, the magnetic dipole moments, spectroscopic quadrupole moments and isotopic changes in mean-square charge radius were deduced. The magnetic dipole moments are consistent with previous data. The /sup 190,192/Tl isotopes show a considerable difference in quadrupole deformations as well as an anomalous isotope shift with respect to 194 Tl. A large isomer shift in 193 Tl is observed implying a larger deformation in the 9/2 - isomer than in the 1/2 + ground state. The /sup 189,191,193/Tl isomers show increasing deformation away from stability. A deformed shell model calculation indicates that this increase in deformation can account for the dropping of the 9/2 - band in these isotopes while an increase in neutron pairing correlations, having opposite and compensating effects on the rotational moment of inertia, maintains the 9/2 - strong-coupled band structure. 105 refs., 27 figs
Delayed ripple counter simplifies square-root computation

Science.gov (United States)

Cliff, R.

1965-01-01

Ripple subtract technique simplifies the logic circuitry required in a binary computing device to derive the square root of a number. Successively higher numbers are subtracted from a register containing the number out of which the square root is to be extracted. The last number subtracted will be the closest integer to the square root of the number.
Effect of survey design and catch rate estimation on total catch estimates in Chinook salmon fisheries

Science.gov (United States)

McCormick, Joshua L.; Quist, Michael C.; Schill, Daniel J.

2012-01-01

Roving–roving and roving–access creel surveys are the primary techniques used to obtain information on harvest of Chinook salmon Oncorhynchus tshawytscha in Idaho sport fisheries. Once interviews are conducted using roving–roving or roving–access survey designs, mean catch rate can be estimated with the ratio-of-means (ROM) estimator, the mean-of-ratios (MOR) estimator, or the MOR estimator with exclusion of short-duration (≤0.5 h) trips. Our objective was to examine the relative bias and precision of total catch estimates obtained from use of the two survey designs and three catch rate estimators for Idaho Chinook salmon fisheries. Information on angling populations was obtained by direct visual observation of portions of Chinook salmon fisheries in three Idaho river systems over an 18-d period. Based on data from the angling populations, Monte Carlo simulations were performed to evaluate the properties of the catch rate estimators and survey designs. Among the three estimators, the ROM estimator provided the most accurate and precise estimates of mean catch rate and total catch for both roving–roving and roving–access surveys. On average, the root mean square error of simulated total catch estimates was 1.42 times greater and relative bias was 160.13 times greater for roving–roving surveys than for roving–access surveys. Length-of-stay bias and nonstationary catch rates in roving–roving surveys both appeared to affect catch rate and total catch estimates. Our results suggest that use of the ROM estimator in combination with an estimate of angler effort provided the least biased and most precise estimates of total catch for both survey designs. However, roving–access surveys were more accurate than roving–roving surveys for Chinook salmon fisheries in Idaho.
Developing detection efficiency standards for atom probe tomography

Science.gov (United States)

Prosa, Ty J.; Geiser, Brian P.; Lawrence, Dan; Olson, David; Larson, David J.

2014-08-01

Atom Probe Tomography (APT) is a near-atomic-scale analytical technique which, due to recent advances in instrumentation and sample preparation techniques, is being used on a variety of 3D applications. Total system detection efficiency is a key parameter for obtaining accurate spatial reconstruction of atomic coordinates from detected ions, but experimental determination of efficiency can be difficult. This work explores new ways to measure total system detection efficiency as well as the specimen characteristics necessary for such measurements. Composite specimens composed of a nickel/chromium multilayer core, National Institute of Standards and Technology Standard Reference Material 2135c, encapsulated with silver, silicon, or nickel were used to demonstrate the suitability of this approach for providing a direct measurement of APT efficiency. Efficiency measurements based on this multilayer encapsulated in nickel are reported.
Interpretation of atom probe tomography data for the intermetallic TiAl+Nb by means of field evaporation simulation

KAUST Repository

Boll, Torben; Al-Kassab, Talaat

2013-01-01

In this paper simulations of the field evaporation process during field ion microscopy (FIM) and atom probe tomography (APT) are presented and compared with experimental data. The Müller-Schottky-model [1] was extended to include the local atomic
Present status and future perspective of development of atomic energy

International Nuclear Information System (INIS)

Takuma, Masao

1990-01-01

The last year was the 50th year from the discovery of the nuclear fission of uranium in 1939. The utilization of atomic energy made the unfortunate start as atomic bombs, but after the 'Atoms for Peace' declaration of President Eisenhauer, it has become to contribute to the development of mankind as nuclear power generation and radiation utilization. In Japan, the Atomic Energy Act was instituted in 1955, and the utilization of atomic energy has been eagerly promoted. As to nuclear power generation, as of the end of June, 1989, 423 power plants were in operation in the world, which generated 333 million kW, equivalent to 17 % of the total generated electric power. The nuclear power plants under construction and at planning stage were 199 with 190 million kW capacity, in this way, the development is advanced actively. At present in Japan, 38 nuclear power plants are in operation, generating 29.46 million kW, which has reached 30 % of the total generated electric power. The social environment surrounding atomic energy and the basic way of thinking on atomic energy development are discussed. The demand and supply of electric power in 21st century and atomic energy, and the policy of electric power companies to cope with it are explained. (K.I.)
Simple and Rapid Quantification of Total Carotenoids in Lyophilized Apricots (Prunus armeniaca L. by Means of Reflectance Colorimetry and Photoacoustic Spectroscopy

Directory of Open Access Journals (Sweden)

Gitta Ficzek

2013-01-01

Full Text Available Photoacoustic spectroscopy (PAS and reflectance colorimetry are suggested as new tools for the analysis of total carotenoids in lyophilized apricot powders. The data obtained by these two techniques from seven apricot cultivars were compared to those acquired by spectrophotometry and high-performance liquid chromatography (HPLC. Best correlations were found between the total carotenoid (TC content (obtained by VIS spectrophotometry: 1.2–3.4 mg per 100 g of fresh mass and colorimetric index a* (a* represents the redness of the investigated sample, as well as either argon-ion laser- or xenon-lamp-based PAS. In all three cases linear correlations were comparable. However, according to the sensitivity and precision data, expressed via limit of detection (LOD and measurement repeatability, the Xe-lamp-based PAS is a preferred approach, followed by colorimetric index a* and Ar-ion laser PAS. Both PAS methods exhibit practically the same Pearson's correlation coefficient (R=0.987 and R=0.991 values. Nevertheless, residual sum of squares (RSS and residual standard deviation of the linear regression (sy/x differ markedly. For Xe-lamp-based PAS these parameters were much lower than in the case of Ar-ion laser PAS. Likewise, analysis imprecision amounted to relative standard deviation (RSD of 1–3 % for Xe-lamp PAS and 2–6 % for Ar-ion laser PAS. On the other hand, as expected, the calibration sensitivity achieved for the PAS signal induced by an Ar-ion laser at 481 nm was substantially higher than that of a Xe-lamp at 470 nm. Nevertheless, according to much lower sy/x, the corresponding LOD for Xe-lamp PAS was still two times lower than that of Ar-ion-based laser PAS (0.59 vs. 1.10 mg per 100 g. Unlike this, Ar-ion laser PAS showed more favourable instrumental precision and standard error of the weighed mean when compared to the Xe-lamp PAS (0.1–0.6 and 0.1–0.3 % vs. 0.5–8.0 and 0.4–1.7 %, respectively. As far as colorimetric indices are
Approximate Teleportation of an Unknown Atomic-Entangled State with Dissipative Atom-Cavity Resonant Jaynes-Cummings Model

Institute of Scientific and Technical Information of China (English)

LIU Zong-Liang; LI Shao-Hua; CHEN Chang-Yong

2008-01-01

We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled state in dissipative cavity QED.It is the further development of the scheme of [Phys.Rev.A 69 (2004) 064302],where the cavity mode decay has not been considered and the state teleportated is an unknown atomic state.In this paper,we investigate the influence of the decay on the approximate and conditional teleportation of the unknown atomic-entangled state,which is different from that teleportated in [Phys.Rev.A 69 (2004) 064302] and then give the fidelity of the teleportation,which depends on the cavity mode decay.The scheme may be generalized to not only the teleportation of the cavity-mode-entangled-state by means of a single atom but also the teleportation of the unknown trapped-ion-entangled-state in a linear ion trap.
Estimating Frequency by Interpolation Using Least Squares Support Vector Regression

Directory of Open Access Journals (Sweden)

Changwei Ma

2015-01-01

Full Text Available Discrete Fourier transform- (DFT- based maximum likelihood (ML algorithm is an important part of single sinusoid frequency estimation. As signal to noise ratio (SNR increases and is above the threshold value, it will lie very close to Cramer-Rao lower bound (CRLB, which is dependent on the number of DFT points. However, its mean square error (MSE performance is directly proportional to its calculation cost. As a modified version of support vector regression (SVR, least squares SVR (LS-SVR can not only still keep excellent capabilities for generalizing and fitting but also exhibit lower computational complexity. In this paper, therefore, LS-SVR is employed to interpolate on Fourier coefficients of received signals and attain high frequency estimation accuracy. Our results show that the proposed algorithm can make a good compromise between calculation cost and MSE performance under the assumption that the sample size, number of DFT points, and resampling points are already known.
Total variation superiorized conjugate gradient method for image reconstruction

Science.gov (United States)

Zibetti, Marcelo V. W.; Lin, Chuan; Herman, Gabor T.

2018-03-01

The conjugate gradient (CG) method is commonly used for the relatively-rapid solution of least squares problems. In image reconstruction, the problem can be ill-posed and also contaminated by noise; due to this, approaches such as regularization should be utilized. Total variation (TV) is a useful regularization penalty, frequently utilized in image reconstruction for generating images with sharp edges. When a non-quadratic norm is selected for regularization, as is the case for TV, then it is no longer possible to use CG. Non-linear CG is an alternative, but it does not share the efficiency that CG shows with least squares and methods such as fast iterative shrinkage-thresholding algorithms (FISTA) are preferred for problems with TV norm. A different approach to including prior information is superiorization. In this paper it is shown that the conjugate gradient method can be superiorized. Five different CG variants are proposed, including preconditioned CG. The CG methods superiorized by the total variation norm are presented and their performance in image reconstruction is demonstrated. It is illustrated that some of the proposed variants of the superiorized CG method can produce reconstructions of superior quality to those produced by FISTA and in less computational time, due to the speed of the original CG for least squares problems. In the Appendix we examine the behavior of one of the superiorized CG methods (we call it S-CG); one of its input parameters is a positive number ɛ. It is proved that, for any given ɛ that is greater than the half-squared-residual for the least squares solution, S-CG terminates in a finite number of steps with an output for which the half-squared-residual is less than or equal to ɛ. Importantly, it is also the case that the output will have a lower value of TV than what would be provided by unsuperiorized CG for the same value ɛ of the half-squared residual.
Manipulating localized molecular orbitals by single-atom contacts.

Science.gov (United States)

Wang, Weihua; Shi, Xingqiang; Lin, Chensheng; Zhang, Rui Qin; Minot, Christian; Van Hove, Michel A; Hong, Yuning; Tang, Ben Zhong; Lin, Nian

2010-09-17

We have fabricated atom-molecule contacts by attachment of single Cu atoms to terpyridine side groups of bis-terpyridine tetra-phenyl ethylene molecules on a Cu(111) surface. By means of scanning tunneling microscopy, spectroscopy, and density functional calculations, we have found that, due to the localization characteristics of molecular orbitals, the Cu-atom contact modifies the state localized at the terpyridine side group which is in contact with the Cu atom but does not affect the states localized at other parts of the molecule. These results illustrate the contact effects at individual orbitals and offer possibilities to manipulate orbital alignments within molecules.
Determination of dietary intake of total arsenic, inorganic arsenic and total mercury in the Chilean school meal program.

Science.gov (United States)

Bastías, J M; Bermúdez, M; Carrasco, J; Espinoza, O; Muñoz, M; Galotto, M J; Muñoz, O

2010-10-01

The dietary intake of total arsenic (tAs), inorganic arsenic (iAs) and total mercury (tHg) in lunch and breakfast servings provided by the Chilean School Meal Program (SMP) was estimated, using the duplicate-portion variant of the total diet study. Lunch and breakfast samples were collected from 65 schools throughout the country in 2006. The population sample was a group of girls and boys between 6 and 18 years old. The tAs concentration was measured via hydride-generation atomic absorption spectrometry. The total mercury concentration was measured via cold-vapor atomic absorption spectroscopy. The estimated iAs intake was 12.5% (5.4 μg/day) of the Provisional tolerable daily intake (PTDI) as proposed by the FAO/WHO, and the tHg intake was 13.2% (1.9 μg/day) of the PTDI as proposed by the FAO/WHO. It was therefore concluded that tAs, iAs and tHg intake from food provided by the SMP do not pose risks to student health.
Electron capture in proton collisions with alkali atoms as a three-body problem

International Nuclear Information System (INIS)

Avakov, G.V.; Blokhintsev, L.D.; Kadyrov, A.S.; Mukhamedzhanov, A.M.

1992-01-01

A previous paper proposed an approach to the calculation of electron transfer reactions in ion-atomic collisions based on the Faddeev three-body equations written in the Alt-Grassberger-Sandhas form. In the present work this approach is used to describe the electron capture in proton collisions with alkali atoms. The results of calculation of the total and partial cross sections for charge exchange in proton collisions with Li, Na, K and Rb atoms are presented. The calculated total cross sections are in good agreement with experiment for light target atoms. In going over to heavier targets, the theoretical total cross sections, while agreeing in form, tend to be larger than the experimental ones. The calculated partial cross sections for electron capture into the 2s state of the H atom are also in agreement with experiment. Some other partial cross sections were also calculated. (author)
A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms.

Science.gov (United States)

Huo, Ming-Xia; Nie, Wei; Hutchinson, David A W; Kwek, Leong Chuan

2014-08-08

Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a "hairline" solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.
A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms

Science.gov (United States)

Huo, Ming-Xia; Nie, Wei; Hutchinson, David A. W.; Kwek, Leong Chuan

2014-08-01

Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a ``hairline'' solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.
[Study on modeling method of total viable count of fresh pork meat based on hyperspectral imaging system].

Science.gov (United States)

Wang, Wei; Peng, Yan-Kun; Zhang, Xiao-Li

2010-02-01

Once the total viable count (TVC) of bacteria in fresh pork meat exceeds a certain number, it will become pathogenic bacteria. The present paper is to explore the feasibility of hyperspectral imaging technology combined with relevant modeling method for the prediction of TVC in fresh pork meat. For the certain kind of problem that has remarkable nonlinear characteristic and contains few samples, as well as the problem that has large amount of data used to express the information of spectrum and space dimension, it is crucial to choose a logical modeling method in order to achieve good prediction result. Based on the comparative result of partial least-squares regression (PLSR), artificial neural networks (ANNs) and least square support vector machines (LS-SVM), the authors found that the PLSR method was helpless for nonlinear regression problem, and the ANNs method couldn't get approving prediction result for few samples problem, however the prediction models based on LS-SVM can give attention to the little training error and the favorable generalization ability as soon as possible, and can make them well synchronously. Therefore LS-SVM was adopted as the modeling method to predict the TVC of pork meat. Then the TVC prediction model was constructed using all the 512 wavelength data acquired by the hyperspectral imaging system. The determination coefficient between the TVC obtained with the standard plate count for bacterial colonies method and the LS-SVM prediction result was 0.987 2 and 0.942 6 for the samples of calibration set and prediction set respectively, also the root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) was 0.207 1 and 0.217 6 individually, and the result was considerably better than that of MLR, PLSR and ANNs method. This research demonstrates that using the hyperspectral imaging system coupled with the LS-SVM modeling method is a valid means for quick and nondestructive determination of TVC of pork
Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

Energy Technology Data Exchange (ETDEWEB)

Malý, Milan, E-mail: milan.maly@vutbr.cz; Janáčková, Lada; Jedelský, Jan, E-mail: jedelsky@vutbr.cz; Jícha, Miroslav [Brno University of Technology, Faculty of Mechanical Engineering, Energy Institute, Technická 2896/2, 61669 Brno (Czech Republic)

2016-06-30

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.
Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

Science.gov (United States)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

2016-06-01

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.

Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

International Nuclear Information System (INIS)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

2016-01-01

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.
Sensing Noncollinear Magnetism at the Atomic Scale Combining Magnetic Exchange and Spin-Polarized Imaging.

Science.gov (United States)

Hauptmann, Nadine; Gerritsen, Jan W; Wegner, Daniel; Khajetoorians, Alexander A

2017-09-13

Storing and accessing information in atomic-scale magnets requires magnetic imaging techniques with single-atom resolution. Here, we show simultaneous detection of the spin-polarization and exchange force with or without the flow of current with a new method, which combines scanning tunneling microscopy and noncontact atomic force microscopy. To demonstrate the application of this new method, we characterize the prototypical nanoskyrmion lattice formed on a monolayer of Fe/Ir(111). We resolve the square magnetic lattice by employing magnetic exchange force microscopy, demonstrating its applicability to noncollinear magnetic structures for the first time. Utilizing distance-dependent force and current spectroscopy, we quantify the exchange forces in comparison to the spin-polarization. For strongly spin-polarized tips, we distinguish different signs of the exchange force that we suggest arises from a change in exchange mechanisms between the probe and a skyrmion. This new approach may enable both nonperturbative readout combined with writing by current-driven reversal of atomic-scale magnets.
Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes

Directory of Open Access Journals (Sweden)

M. Bahn

2010-07-01

Full Text Available Soil respiration (SR constitutes the largest flux of CO₂ from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SR_MAT, irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q₁₀. We further show that for seasonally dry sites where annual precipitation (P is lower than potential evapotranspiration (PET, annual SR can be predicted from wet season SR_MAT corrected for a factor related to P/PET. Our finding indicates that it can be sufficient to measure SR_MAT for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO₂ emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle.
From least squares to multilevel modeling: A graphical introduction to Bayesian inference

Science.gov (United States)

Loredo, Thomas J.

2016-01-01

This tutorial presentation will introduce some of the key ideas and techniques involved in applying Bayesian methods to problems in astrostatistics. The focus will be on the big picture: understanding the foundations (interpreting probability, Bayes's theorem, the law of total probability and marginalization), making connections to traditional methods (propagation of errors, least squares, chi-squared, maximum likelihood, Monte Carlo simulation), and highlighting problems where a Bayesian approach can be particularly powerful (Poisson processes, density estimation and curve fitting with measurement error). The "graphical" component of the title reflects an emphasis on pictorial representations of some of the math, but also on the use of graphical models (multilevel or hierarchical models) for analyzing complex data. Code for some examples from the talk will be available to participants, in Python and in the Stan probabilistic programming language.
The Square Light Clock and Special Relativity

Science.gov (United States)

Galli, J. Ronald; Amiri, Farhang

2012-01-01

A thought experiment that includes a square light clock is similar to the traditional vertical light beam and mirror clock, except it is made up of four mirrors placed at a 45[degree] angle at each corner of a square of length L[subscript 0], shown in Fig. 1. Here we have shown the events as measured in the rest frame of the square light clock. By…
Relativistic correlations in atoms

International Nuclear Information System (INIS)

Dietz, K.

1987-01-01

Atoms are particularly well-suited objects when it comes to testing certain concepts of many-body theories. They play a unique role in this respect because of two constructively interfering reasons: first of all, the laws describing the interactions of their constituents are the ones best known in all of Physics; secondly, their structure is comparatively simple and amenable to concise theoretical treatment. Because of these two reasons, physically motivated many-body approximation schemes, ordered in a systematic hierarchy of precision, can be carefully tested; discrepancies between theory and experiment are due to many-body effects and are never masked by uncertainties in the constituent-interaction (needless to say, the very small hadronic contributions to atomic structure is left out. Many-body effects in atoms are solely produced by the electron-electron interaction which derives from the laws of Quantum Electrodynamics or, in a very good approximation from the repulsive Coulomb potential; in the general nomenclature they are named correlations. The material is organized in two chapters: chapter 1 deals with a general introduction and discussion of g-Hartree mean-field theories, chapter 2 deals with applications. The role of vacuum fluctuations and deformations of the Dirac sea in a consistent construction of mean-fields is emphasized and their explicit form in the g-Hartree theory is given. 21 references, 5 figures, 3 tables
A Compact, High-Flux Cold Atom Beam Source

Science.gov (United States)

Kellogg, James R.; Kohel, James M.; Thompson, Robert J.; Aveline, David C.; Yu, Nan; Schlippert, Dennis

2012-01-01

The performance of cold atom experiments relying on three-dimensional magneto-optical trap techniques can be greatly enhanced by employing a highflux cold atom beam to obtain high atom loading rates while maintaining low background pressures in the UHV MOT (ultra-high vacuum magneto-optical trap) regions. Several techniques exist for generating slow beams of cold atoms. However, one of the technically simplest approaches is a two-dimensional (2D) MOT. Such an atom source typically employs at least two orthogonal trapping beams, plus an additional longitudinal "push" beam to yield maximum atomic flux. A 2D atom source was created with angled trapping collimators that not only traps atoms in two orthogonal directions, but also provides a longitudinal pushing component that eliminates the need for an additional push beam. This development reduces the overall package size, which in turn, makes the 2D trap simpler, and requires less total optical power. The atom source is more compact than a previously published effort, and has greater than an order of magnitude improved loading performance.
Partial Least Square with Savitzky Golay Derivative in Predicting Blood Hemoglobin Using Near Infrared Spectrum

Directory of Open Access Journals (Sweden)

Mohd Idrus Mohd Nazrul Effendy

2018-01-01

Full Text Available Near infrared spectroscopy (NIRS is a reliable technique that widely used in medical fields. Partial least square was developed to predict blood hemoglobin concentration using NIRS. The aims of this paper are (i to develop predictive model for near infrared spectroscopic analysis in blood hemoglobin prediction, (ii to establish relationship between blood hemoglobin and near infrared spectrum using a predictive model, (iii to evaluate the predictive accuracy of a predictive model based on root mean squared error (RMSE and coefficient of determination rp2. Partial least square with first order Savitzky Golay (SG derivative preprocessing (PLS-SGd1 showed the higher performance of predictions with RMSE = 0.7965 and rp2= 0.9206 in K-fold cross validation. Optimum number of latent variable (LV and frame length (f were 32 and 27 nm, respectively. These findings suggest that the relationship between blood hemoglobin and near infrared spectrum is strong, and the partial least square with first order SG derivative is able to predict the blood hemoglobin using near infrared spectral data.
Finding reproducible cluster partitions for the k-means algorithm.

Science.gov (United States)

Lisboa, Paulo J G; Etchells, Terence A; Jarman, Ian H; Chambers, Simon J

2013-01-01

K-means clustering is widely used for exploratory data analysis. While its dependence on initialisation is well-known, it is common practice to assume that the partition with lowest sum-of-squares (SSQ) total i.e. within cluster variance, is both reproducible under repeated initialisations and also the closest that k-means can provide to true structure, when applied to synthetic data. We show that this is generally the case for small numbers of clusters, but for values of k that are still of theoretical and practical interest, similar values of SSQ can correspond to markedly different cluster partitions. This paper extends stability measures previously presented in the context of finding optimal values of cluster number, into a component of a 2-d map of the local minima found by the k-means algorithm, from which not only can values of k be identified for further analysis but, more importantly, it is made clear whether the best SSQ is a suitable solution or whether obtaining a consistently good partition requires further application of the stability index. The proposed method is illustrated by application to five synthetic datasets replicating a real world breast cancer dataset with varying data density, and a large bioinformatics dataset.
PETOS-BASIC programs for treating data and reporting results in atomic spectroscopy

International Nuclear Information System (INIS)

Roca, M.

1985-01-01

A PETOS-BASIC program was written which provides the off-line treatment of data in optical emission spectroscopy, flame photometry and, atomic absorption spectroscopy. Polynomial calibration functions are fitted in overlapped steps by the least squares method. The calculated concentrations in unknown samples are stored in sequential files (one per element, up to four), from which they can be read to be reported in a second program. (Author) 7 refs
Spectrum unfolding by the least-squares methods

International Nuclear Information System (INIS)

Perey, F.G.

1977-01-01

The method of least squares is briefly reviewed, and the conditions under which it may be used are stated. From this analysis, a least-squares approach to the solution of the dosimetry neutron spectrum unfolding problem is introduced. The mathematical solution to this least-squares problem is derived from the general solution. The existence of this solution is analyzed in some detail. A chi 2 -test is derived for the consistency of the input data which does not require the solution to be obtained first. The fact that the problem is technically nonlinear, but should be treated in general as a linear one, is argued. Therefore, the solution should not be obtained by iteration. Two interpretations are made for the solution of the code STAY'SL, which solves this least-squares problem. The relationship of the solution to this least-squares problem to those obtained currently by other methods of solving the dosimetry neutron spectrum unfolding problem is extensively discussed. It is shown that the least-squares method does not require more input information than would be needed by current methods in order to estimate the uncertainties in their solutions. From this discussion it is concluded that the proposed least-squares method does provide the best complete solution, with uncertainties, to the problem as it is understood now. Finally, some implications of this method are mentioned regarding future work required in order to exploit its potential fully
Merging physical parameters and laboratory subjective ratings for the soundscape assessment of urban squares.

Science.gov (United States)

Brambilla, Giovanni; Maffei, Luigi; Di Gabriele, Maria; Gallo, Veronica

2013-07-01

An experimental study was carried out in 20 squares in the center of Rome, covering a wide range of different uses, sonic environments, geometry, and architectural styles. Soundwalks along the perimeter of each square were performed during daylight and weekdays taking binaural and video recordings, as well as spot measurements of illuminance. The cluster analysis performed on the physical parameters, not only acoustic, provided two clusters that are in satisfactory agreement with the "a priori" classification. Applying the principal component analysis (PCA) to five physical parameters, two main components were obtained which might be associated to two environmental features, namely, "chaotic/calm" and "open/enclosed." On the basis of these two features, six squares were selected for the laboratory audio-video tests where 32 subjects took part filling in a questionnaire. The PCA performed on the subjective ratings on the sonic environment showed two main components which might be associated to two emotional meanings, namely, "calmness" and "vibrancy." The linear regression modeling between five objective parameters and the mean value of subjective ratings on chaotic/calm and enclosed/open attributes showed a good correlation. Notwithstanding these interesting results being limited to the specific data set, it is worth pointing out that the complexity of the soundscape quality assessment can be more comprehensively examined merging the field measurements of physical parameters with the subjective ratings provided by field and/or laboratory tests.
Total Synthesis of Adunctin B.

Science.gov (United States)

Dethe, Dattatraya H; Dherange, Balu D

2018-03-16

Total synthesis of (±)-adunctin B, a natural product isolated from Piper aduncum (Piperaceae), has been achieved using two different strategies, in seven and three steps. The efficient approach features highly atom economical and diastereoselective Friedel-Crafts acylation, alkylation reaction and palladium catalyzed Wacker type oxidative cyclization.
Sapphire: a better material for atomization and in situ collection of silver volatile species for atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Musil, Stanislav, E-mail: stanomusil@biomed.cas.cz; Matoušek, Tomáš; Dědina, Jiří

2015-06-01

Sapphire is presented as a high temperature and corrosion resistant material of an optical tube of an atomizer for volatile species of Ag generated by the reaction with NaBH{sub 4}. The modular atomizer design was employed which allowed to carry out the measurements in two modes: (i) on-line atomization and (ii) in situ collection (directly in the optical tube) by means of excess of O{sub 2} over H{sub 2} in the carrier gas during the trapping step and vice versa in the volatilization step. In comparison with quartz atomizers, the sapphire tube atomizer provides a significantly increased atomizer lifetime as well as substantially improved repeatability of the Ag in situ collection signals shapes. In situ collection of Ag in the sapphire tube atomizer was highly efficient (> 90%). Limit of detection in the on-line atomization mode and in situ collection mode, respectively, was 1.2 ng ml{sup −1} and 0.15 ng ml{sup −1}. - Highlights: • Sapphire was tested as a new material of an atomizer tube for Ag volatile species. • Two measurement modes were investigated: on-line atomization and in situ collection. • In situ collection of Ag was highly efficient (> 90%) with LOD of 0.15 ng ml{sup −1}. • No devitrification of the sapphire tube observed in the course of several months.
Elmo bumpy square plasma confinement device

Science.gov (United States)

Owen, L.W.

1985-01-01

The invention is an Elmo bumpy type plasma confinement device having a polygonal configuration of closed magnet field lines for improved plasma confinement. In the preferred embodiment, the device is of a square configuration which is referred to as an Elmo bumpy square (EBS). The EBS is formed by four linear magnetic mirror sections each comprising a plurality of axisymmetric assemblies connected in series and linked by 90/sup 0/ sections of a high magnetic field toroidal solenoid type field generating coils. These coils provide corner confinement with a minimum of radial dispersion of the confined plasma to minimize the detrimental effects of the toroidal curvature of the magnetic field. Each corner is formed by a plurality of circular or elliptical coils aligned about the corner radius to provide maximum continuity in the closing of the magnetic field lines about the square configuration confining the plasma within a vacuum vessel located within the various coils forming the square configuration confinement geometry.
X-ray absorption edges and E.X.A.F.S.: application to the study of electronic and atomic structures of titanium and vanadium carbides TiC(1-x) and VC(1-x)

International Nuclear Information System (INIS)

Moisy-Maurice, Virginie.

1980-09-01

This text presents a systematic study of the X-ray absorption fine structures evolution, at the K edge of titanium, with vacancy concentration in TiC(1-x). The absorption edges are situated in the 50 eV following the coefficient discontinuity: from the evaluation of their general aspect, it is deduced that the positive charge of titanium atoms decreases when vacancy concentration increases in TiC(1-x). This allowed us to determine the best band structure calculation model. The interpretation of EXAFS spectra (modulation of the absorption coefficient until 1500 eV above the edge) gives indications about the local atomic structure. Here, the contraction of the average titanium-carbon interatomic distances compared to the distances between crystallographic sites is of the order of the experimental resolution 0.02 A for Ti C(0.8). The study of the damping of the spectra in terms of Debye-Waller factors gave an evaluation of the relative static atomic mean square displacements between first neighbours. Last, it has been established that the disordering of vacancies in the order-disorder transition of V 8 C 7 is an atomic scale phenomenon [fr
Revealing molecular-level surface structure of amyloid fibrils in liquid by means of frequency modulation atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fukuma, Takeshi [Frontier Science Organization, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Mostaert, Anika S; Jarvis, Suzanne P [Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland (Ireland); Serpell, Louise C [Department of Biochemistry, University of Sussex, John Maynard Building, Falmer BN1 9QG (United Kingdom)], E-mail: fukuma@staff.kanazawa-u.ac.jp, E-mail: Anika.Mostaert@ucd.ie, E-mail: L.C.Serpell@sussex.ac.uk, E-mail: Suzi.Jarvis@ucd.ie

2008-09-24

We have investigated the surface structure of islet amyloid polypeptide (IAPP) fibrils and {alpha}-synuclein protofibrils in liquid by means of frequency modulation atomic force microscopy (FM-AFM). Angstroem-resolution FM-AFM imaging of isolated macromolecules in liquid is demonstrated for the first time. Individual {beta}-strands aligned perpendicular to the fibril axis with a spacing of 0.5 nm are resolved in FM-AFM images, which confirms cross-{beta} structure of IAPP fibrils in real space. FM-AFM images also reveal the existence of 4 nm periodic domains along the axis of IAPP fibrils. Stripe features with 0.5 nm spacing are also found in images of {alpha}-synuclein protofibrils. However, in contrast to the case for IAPP fibrils, the stripes are oriented 30 deg. from the axis, suggesting the possibility of {beta}-strand alignment in protofibrils different from that in mature fibrils or the regular arrangement of thioflavin T molecules present during the fibril preparation aligned at the surface of the protofibrils.
Revealing molecular-level surface structure of amyloid fibrils in liquid by means of frequency modulation atomic force microscopy

International Nuclear Information System (INIS)

Fukuma, Takeshi; Mostaert, Anika S; Jarvis, Suzanne P; Serpell, Louise C

2008-01-01

We have investigated the surface structure of islet amyloid polypeptide (IAPP) fibrils and α-synuclein protofibrils in liquid by means of frequency modulation atomic force microscopy (FM-AFM). Angstroem-resolution FM-AFM imaging of isolated macromolecules in liquid is demonstrated for the first time. Individual β-strands aligned perpendicular to the fibril axis with a spacing of 0.5 nm are resolved in FM-AFM images, which confirms cross-β structure of IAPP fibrils in real space. FM-AFM images also reveal the existence of 4 nm periodic domains along the axis of IAPP fibrils. Stripe features with 0.5 nm spacing are also found in images of α-synuclein protofibrils. However, in contrast to the case for IAPP fibrils, the stripes are oriented 30 deg. from the axis, suggesting the possibility of β-strand alignment in protofibrils different from that in mature fibrils or the regular arrangement of thioflavin T molecules present during the fibril preparation aligned at the surface of the protofibrils
Exploring the electron density localization in single MoS2 monolayers by means of a localize-electrons detector and the quantum theory of atoms in molecules

Directory of Open Access Journals (Sweden)

Yosslen Aray

2017-11-01

Full Text Available The nature of the electron density localization in a MoS2 monolayer under 0 % to 11% tensile strain has been systematically studied by means of a localized electron detector function and the Quantum Theory of atoms in molecules. At 10% tensile strain, this monolayer become metallic. It was found that for less than 6.5% of applied stress, the same atomic structure of the equilibrium geometry (0% strain is maintained; while over 6.5% strain induces a transformation to a structure where the sulfur atoms placed on the top and bottom layer form S2 groups. The localized electron detector function shows the presence of zones of highly electron delocalization extending throughout the Mo central layer. For less than 10% tensile strain, these zones comprise the BCPs and the remainder CPs in separates regions of the space; while for the structures beyond 10% strain, all the critical points are involved in a region of highly delocalized electrons that extends throughout the material. This dissimilar electron localization pattern is like to that previously reported for semiconductors such as Ge bulk and metallic systems such as transition metals bulk.
Least Squares Estimate of the Initial Phases in STFT based Speech Enhancement

DEFF Research Database (Denmark)

Nørholm, Sidsel Marie; Krawczyk-Becker, Martin; Gerkmann, Timo

2015-01-01

In this paper, we consider single-channel speech enhancement in the short time Fourier transform (STFT) domain. We suggest to improve an STFT phase estimate by estimating the initial phases. The method is based on the harmonic model and a model for the phase evolution over time. The initial phases...... are estimated by setting up a least squares problem between the noisy phase and the model for phase evolution. Simulations on synthetic and speech signals show a decreased error on the phase when an estimate of the initial phase is included compared to using the noisy phase as an initialisation. The error...... on the phase is decreased at input SNRs from -10 to 10 dB. Reconstructing the signal using the clean amplitude, the mean squared error is decreased and the PESQ score is increased....

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