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Sample records for regular lamellar coupled

  1. Coupling regularizes individual units in noisy populations

    International Nuclear Information System (INIS)

    Ly Cheng; Ermentrout, G. Bard

    2010-01-01

    The regularity of a noisy system can modulate in various ways. It is well known that coupling in a population can lower the variability of the entire network; the collective activity is more regular. Here, we show that diffusive (reciprocal) coupling of two simple Ornstein-Uhlenbeck (O-U) processes can regularize the individual, even when it is coupled to a noisier process. In cellular networks, the regularity of individual cells is important when a select few play a significant role. The regularizing effect of coupling surprisingly applies also to general nonlinear noisy oscillators. However, unlike with the O-U process, coupling-induced regularity is robust to different kinds of coupling. With two coupled noisy oscillators, we derive an asymptotic formula assuming weak noise and coupling for the variance of the period (i.e., spike times) that accurately captures this effect. Moreover, we find that reciprocal coupling can regularize the individual period of higher dimensional oscillators such as the Morris-Lecar and Brusselator models, even when coupled to noisier oscillators. Coupling can have a counterintuitive and beneficial effect on noisy systems. These results have implications for the role of connectivity with noisy oscillators and the modulation of variability of individual oscillators.

  2. Adiabatic regularization of power spectra in nonminimally coupled chaotic inflation

    Energy Technology Data Exchange (ETDEWEB)

    Alinea, Allan L., E-mail: alinea@het.phys.sci.osaka-u.ac.jp [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

    2016-10-01

    We investigate the effect of adiabatic regularization on both the tensor- and scalar-perturbation power spectra in nonminimally coupled chaotic inflation. Similar to that of the minimally coupled general single-field inflation, we find that the subtraction term is suppressed by an exponentially decaying factor involving the number of e -folds. By following the subtraction term long enough beyond horizon crossing, the regularized power spectrum tends to the ''bare'' power spectrum. This study justifies the use of the unregularized (''bare'') power spectrum in standard calculations.

  3. Properties of regular polygons of coupled microring resonators.

    Science.gov (United States)

    Chremmos, Ioannis; Uzunoglu, Nikolaos

    2007-11-01

    The resonant properties of a closed and symmetric cyclic array of N coupled microring resonators (coupled-microring resonator regular N-gon) are for the first time determined analytically by applying the transfer matrix approach and Floquet theorem for periodic propagation in cylindrically symmetric structures. By solving the corresponding eigenvalue problem with the field amplitudes in the rings as eigenvectors, it is shown that, for even or odd N, this photonic molecule possesses 1 + N/2 or 1+N resonant frequencies, respectively. The condition for resonances is found to be identical to the familiar dispersion equation of the infinite coupled-microring resonator waveguide with a discrete wave vector. This result reveals the so far latent connection between the two optical structures and is based on the fact that, for a regular polygon, the field transfer matrix over two successive rings is independent of the polygon vertex angle. The properties of the resonant modes are discussed in detail using the illustration of Brillouin band diagrams. Finally, the practical application of a channel-dropping filter based on polygons with an even number of rings is also analyzed.

  4. Supersymmetric Regularization Two-Loop QCD Amplitudes and Coupling Shifts

    International Nuclear Information System (INIS)

    Dixon, Lance

    2002-01-01

    We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme and is designed to be compatible with the use of helicity states for ''observed'' particles. It is similar to dimensional reduction in that it maintains an equal number of bosonic and fermionic states, as required for preserving supersymmetry. Supersymmetry Ward identities relate different helicity amplitudes in supersymmetric theories. As a check that the FDH scheme preserves supersymmetry, at least through two loops, we explicitly verify a number of these identities for gluon-gluon scattering (gg → gg) in supersymmetric QCD. These results also cross-check recent non-trivial two-loop calculations in ordinary QCD. Finally, we compute the two-loop shift between the FDH coupling and the standard MS coupling, α s . The FDH shift is identical to the one for dimensional reduction. The two-loop coupling shifts are then used to obtain the three-loop QCD β function in the FDH and dimensional reduction schemes

  5. Supersymmetric Regularization Two-Loop QCD Amplitudes and Coupling Shifts

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Lance

    2002-03-08

    We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme and is designed to be compatible with the use of helicity states for ''observed'' particles. It is similar to dimensional reduction in that it maintains an equal number of bosonic and fermionic states, as required for preserving supersymmetry. Supersymmetry Ward identities relate different helicity amplitudes in supersymmetric theories. As a check that the FDH scheme preserves supersymmetry, at least through two loops, we explicitly verify a number of these identities for gluon-gluon scattering (gg {yields} gg) in supersymmetric QCD. These results also cross-check recent non-trivial two-loop calculations in ordinary QCD. Finally, we compute the two-loop shift between the FDH coupling and the standard {bar M}{bar S} coupling, {alpha}{sub s}. The FDH shift is identical to the one for dimensional reduction. The two-loop coupling shifts are then used to obtain the three-loop QCD {beta} function in the FDH and dimensional reduction schemes.

  6. Strong self-coupling expansion in the lattice-regularized standard SU(2) Higgs model

    International Nuclear Information System (INIS)

    Decker, K.; Weisz, P.; Montvay, I.

    1985-11-01

    Expectation values at an arbitrary point of the 3-dimensional coupling parameter space in the lattice-regularized SU(2) Higgs-model with a doublet scalar field are expressed by a series of expectation values at infinite self-coupling (lambda=infinite). Questions of convergence of this 'strong self-coupling expansion' (SSCE) are investigated. The SSCE is a potentially useful tool for the study of the lambda-dependence at any value (zero or non-zero) of the bare gauge coupling. (orig.)

  7. Strong self-coupling expansion in the lattice-regularized standard SU(2) Higgs model

    International Nuclear Information System (INIS)

    Decker, K.; Weisz, P.

    1986-01-01

    Expectation values at an arbitrary point of the 3-dimensional coupling parameter space in the lattice-regularized SU(2) Higgs model with a doublet scalar field are expressed by a series of expectation values at infinite self-coupling (lambda=infinite). Questions of convergence of this ''strong self-coupling expansion'' (SSCE) are investigated. The SSCE is a potentially useful tool for the study of the lambda-dependence at any value (zero or non-zero) of the bare gauge coupling. (orig.)

  8. Double shadow of a regular phantom black hole as photons couple to the Weyl tensor

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yang; Chen, Songbai; Jing, Jiliang [Hunan Normal University, Institute of Physics and Department of Physics, Changsha, Hunan (China); Hunan Normal University, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Changsha, Hunan (China); Hunan Normal University, Synergetic Innovation Center for Quantum Effects and Applications, Changsha, Hunan (China)

    2016-11-15

    We have studied the shadow of a regular phantom black hole as photons couple to the Weyl tensor. We find that due to the coupling photons with different polarization directions propagate along different paths in the spacetime so that there exists a double shadow for a black hole, which is quite different from that in the non-coupling case where only a single shadow emerges. The overlap region of the double shadow, the umbra, of the black hole increases with the phantom charge and decreases with the coupling strength. The dependence of the penumbra on the phantom charge and the coupling strength is converse to that of the umbra. Combining with the supermassive central object in our Galaxy, we estimated the shadow of the black hole as the photons couple to the Weyl tensor. Our results show that the coupling brings about richer behaviors of the propagation of coupled photon and the shadow of the black hole in the regular phantom black hole spacetime. (orig.)

  9. Assessment of lamellar tearing

    International Nuclear Information System (INIS)

    McEnerney, J.W.

    1978-03-01

    Information on lamellar tearing is summarized and related to proposed ASME Code requirements. Lamellar tearing is characterized as a complex phenomenon related to poor short transverse ductility and through-thickness strain. The material, welding, and design variables that affect lamellar tearing are shown to be complex and interrelated. The commonly reported tests for assessing material susceptibility are described, with the controversy over their validity being carefully detailed. Although the use of a nondestructive test such as ultrasonic examination is most desirable, a widely applicable test method does not appear to be available. Of the destructive tests, the short transverse tensile reduction-of-area currently offers the most applicable means of assessing material susceptibility. However, because of the importance of matrix toughness, the short transverse Charpy V-notch test should be considered for use as an additional test if acceptance limits are developed. The ultrasonic detection of lamellar tears is susceptible to interpretation errors, which can make it overly conservative and lead to unnecessary repairs. The repair of tears is described as costly, difficult, and sometimes ineffective. Current design requirements appear to preclude any failures during static and fatigue service loads. However, without improvement of short transverse ductility, certain dynamic service loads could cause lamellar tearing failures. Two alternate design paths are recommended to prevent tearing during fabrication or service loading. The current and proposed ASME requirements dealing with lamellar tearing are reviewed and recommendations are made

  10. Adiabatic regularization of the power spectrum in nonminimally coupled general single-field inflation

    Science.gov (United States)

    Alinea, Allan L.; Kubota, Takahiro

    2018-03-01

    We perform adiabatic regularization of power spectrum in nonminimally coupled general single-field inflation with varying speed of sound. The subtraction is performed within the framework of earlier study by Urakawa and Starobinsky dealing with the canonical inflation. Inspired by Fakir and Unruh's model on nonminimally coupled chaotic inflation, we find upon imposing near scale-invariant condition, that the subtraction term exponentially decays with the number of e -folds. As in the result for the canonical inflation, the regularized power spectrum tends to the "bare" power spectrum as the Universe expands during (and even after) inflation. This work justifies the use of the "bare" power spectrum in standard calculation in the most general context of slow-roll single-field inflation involving nonminimal coupling and varying speed of sound.

  11. New techniques in lamellar keratoplasty.

    Science.gov (United States)

    Alio, Jorge L; Shah, Sunil; Barraquer, Carmen; Bilgihan, Kamil; Anwar, Mohammed; Melles, Gerrit R J

    2002-08-01

    In the past years, several lamellar keratoplasty surgical techniques have been developed, modified or improved in the past years, including microkeratome assisted anterior and posterior lamellar keratoplasty, anterior lamellar keratoplasty using air-dissection or visco-dissection, sutureless posterior lamellar keratoplasty, LASIK for postkeratoplasty astigmatism, and excimer laser assisted keratophakia for keratoconus or to manage complications after LASIK. These procedures may continue to gain interest as alternative procedures for a penetrating keratoplasty in the treatment of various corneal disorders.

  12. Transition from regularity to Li-Yorke chaos in coupled logistic networks

    International Nuclear Information System (INIS)

    Li Xiang; Chen Guanrong

    2005-01-01

    The transition from regularity to chaos in the sense of Li-Yorke is investigated in this Letter. A logistic network is investigated in detail, where all nodes in the network are the same logistic maps in non-chaotic states (with the parameter μ in non-chaotic regions). It is proved that when μ>1, these non-chaotic logistic nodes can become chaotic in the sense of Li-Yorke. Extensive simulations lead to the conjecture that when μ=<1 such a logistic network is 'super-stable', because no matter how strong the coupling strength is, the network does not transfer to a chaotic state

  13. Regular and irregular patterns of self-localized excitation in arrays of coupled phase oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Wolfrum, Matthias; Omel' chenko, Oleh E. [Weierstrass Institute, Mohrenstrasse 39, Berlin 10117 (Germany); Sieber, Jan [College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road, Exeter EX4 4QF (United Kingdom)

    2015-05-15

    We study a system of phase oscillators with nonlocal coupling in a ring that supports self-organized patterns of coherence and incoherence, called chimera states. Introducing a global feedback loop, connecting the phase lag to the order parameter, we can observe chimera states also for systems with a small number of oscillators. Numerical simulations show a huge variety of regular and irregular patterns composed of localized phase slipping events of single oscillators. Using methods of classical finite dimensional chaos and bifurcation theory, we can identify the emergence of chaotic chimera states as a result of transitions to chaos via period doubling cascades, torus breakup, and intermittency. We can explain the observed phenomena by a mechanism of self-modulated excitability in a discrete excitable medium.

  14. Does quantum mechanics select out regularity and local mode behaviour in nonlinearly coupled vibrational systems?

    International Nuclear Information System (INIS)

    Yurtsever, E.; Brickmann, J.

    1990-01-01

    A two dimensional strongly nonharmonic vibrational system with nonlinear intermode coupling is studied both classically and quantum mechanically. The system was chosen such that there is a low lying transition (in energy) from a region where almost all trajectories move regularly to a region where chaotic dynamics strongly dominates. The corresponding quantum system is far away from the semiclassical limit. The eigenfunctions are calculated with high precision according to a linear variational scheme using conveniently chosen basis functions. It is the aim of this paper to check whether the prediction from semiclassical theory, namely that the measure of classically chaotic trajectories in phase space approaches the measure of irregular states in corresponding energy ranges, holds when the system is not close to the classical limit. It is also the aim to identify individual eigenfunctions with respect to regularity and to differentiate between local and normal vibrational states. It is found that there are quantitative and also qualitative differences between the quantum results and the semiclassical predictions. (orig./HK)

  15. Cross-Modality Image Synthesis via Weakly Coupled and Geometry Co-Regularized Joint Dictionary Learning.

    Science.gov (United States)

    Huang, Yawen; Shao, Ling; Frangi, Alejandro F

    2018-03-01

    Multi-modality medical imaging is increasingly used for comprehensive assessment of complex diseases in either diagnostic examinations or as part of medical research trials. Different imaging modalities provide complementary information about living tissues. However, multi-modal examinations are not always possible due to adversary factors, such as patient discomfort, increased cost, prolonged scanning time, and scanner unavailability. In additionally, in large imaging studies, incomplete records are not uncommon owing to image artifacts, data corruption or data loss, which compromise the potential of multi-modal acquisitions. In this paper, we propose a weakly coupled and geometry co-regularized joint dictionary learning method to address the problem of cross-modality synthesis while considering the fact that collecting the large amounts of training data is often impractical. Our learning stage requires only a few registered multi-modality image pairs as training data. To employ both paired images and a large set of unpaired data, a cross-modality image matching criterion is proposed. Then, we propose a unified model by integrating such a criterion into the joint dictionary learning and the observed common feature space for associating cross-modality data for the purpose of synthesis. Furthermore, two regularization terms are added to construct robust sparse representations. Our experimental results demonstrate superior performance of the proposed model over state-of-the-art methods.

  16. Regularized principal covariates regression and its application to finding coupled patterns in climate fields

    Science.gov (United States)

    Fischer, M. J.

    2014-02-01

    There are many different methods for investigating the coupling between two climate fields, which are all based on the multivariate regression model. Each different method of solving the multivariate model has its own attractive characteristics, but often the suitability of a particular method for a particular problem is not clear. Continuum regression methods search the solution space between the conventional methods and thus can find regression model subspaces that mix the attractive characteristics of the end-member subspaces. Principal covariates regression is a continuum regression method that is easily applied to climate fields and makes use of two end-members: principal components regression and redundancy analysis. In this study, principal covariates regression is extended to additionally span a third end-member (partial least squares or maximum covariance analysis). The new method, regularized principal covariates regression, has several attractive features including the following: it easily applies to problems in which the response field has missing values or is temporally sparse, it explores a wide range of model spaces, and it seeks a model subspace that will, for a set number of components, have a predictive skill that is the same or better than conventional regression methods. The new method is illustrated by applying it to the problem of predicting the southern Australian winter rainfall anomaly field using the regional atmospheric pressure anomaly field. Regularized principal covariates regression identifies four major coupled patterns in these two fields. The two leading patterns, which explain over half the variance in the rainfall field, are related to the subtropical ridge and features of the zonally asymmetric circulation.

  17. Does lamellar surgery for keratoconus experience the popularity it deserves?

    Science.gov (United States)

    Wisse, Robert P L; van den Hoven, Célinde M L; Van der Lelij, Allegonda

    2014-08-01

    To analyse developments in surgical treatment for keratoconus (KC) by assessing rates and types of corneal surgery from 2005 to 2010. The Dutch Transplantation Foundation supplied data on all keratoplasty procedures for KC performed from 2005 to 2010 in the Netherlands. Registration was carried out by the eyebank at allocation and by the surgeon at the time of surgery. The type of surgery was categorized as either a penetrating or a lamellar procedure. Five hundred and seventy-five anonymized records were received, with excellent data completion (99%). Patients undergoing penetrating surgery had on average a lower visual acuity, higher k-readings and were slightly older compared with the lamellar group. A previous corneal hydrops was recorded for 19.1% of patients. Regular penetrating keratoplasty decreased in popularity from 79.7% in 2005 to 43.7% in 2010, due to the increased rate of lamellar surgery (42.5% in 2010) and 'mushroom' penetrating keratoplasty (13.8% in 2010). When hydrops cases were excluded, popularity became equal (47.6% penetrating versus 52.4% lamellar surgery, in 2010). Lamellar surgery is gaining in popularity, although regular penetrating keratoplasty is still the more commonly performed procedure. Only when hydrops cases are excluded do transplant rates become comparable. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  18. Parameter identification for continuous point emission source based on Tikhonov regularization method coupled with particle swarm optimization algorithm.

    Science.gov (United States)

    Ma, Denglong; Tan, Wei; Zhang, Zaoxiao; Hu, Jun

    2017-03-05

    In order to identify the parameters of hazardous gas emission source in atmosphere with less previous information and reliable probability estimation, a hybrid algorithm coupling Tikhonov regularization with particle swarm optimization (PSO) was proposed. When the source location is known, the source strength can be estimated successfully by common Tikhonov regularization method, but it is invalid when the information about both source strength and location is absent. Therefore, a hybrid method combining linear Tikhonov regularization and PSO algorithm was designed. With this method, the nonlinear inverse dispersion model was transformed to a linear form under some assumptions, and the source parameters including source strength and location were identified simultaneously by linear Tikhonov-PSO regularization method. The regularization parameters were selected by L-curve method. The estimation results with different regularization matrixes showed that the confidence interval with high-order regularization matrix is narrower than that with zero-order regularization matrix. But the estimation results of different source parameters are close to each other with different regularization matrixes. A nonlinear Tikhonov-PSO hybrid regularization was also designed with primary nonlinear dispersion model to estimate the source parameters. The comparison results of simulation and experiment case showed that the linear Tikhonov-PSO method with transformed linear inverse model has higher computation efficiency than nonlinear Tikhonov-PSO method. The confidence intervals from linear Tikhonov-PSO are more reasonable than that from nonlinear method. The estimation results from linear Tikhonov-PSO method are similar to that from single PSO algorithm, and a reasonable confidence interval with some probability levels can be additionally given by Tikhonov-PSO method. Therefore, the presented linear Tikhonov-PSO regularization method is a good potential method for hazardous emission

  19. LAMELLAR ICHTHYOSIS (COLLODION BABY

    Directory of Open Access Journals (Sweden)

    Paramarta IGE

    2012-11-01

    Full Text Available The ichthyosis are a heterogeneous group of hereditary and acquired disorder of keratinization which affected the epidermis characterized by presence of visible scales on the skin surface in the absence of inflammation. It can occur as a disease limited to the skin or in association with abnormalities of other organ systems. Lamelar ihthyosis (LI is one of two mayor autosomal recessive ichthyosis with an incidence of approximately one in 300,000. The diagnosis is based on clinical and pathologic finding. Infection is the most common complication, while prognosis of LI is depends on severity and complication of the disease. A case of lamellar ichthyosis in 0 day Balinese female baby was reported. The skin of the body was thick, plate-like appearance, scaling on the entire body, some of the thick skin was ruptured on chest and extremities. There were eclabium on the mouth and ectropion on the eyes. Histopathology examination showed hyperkeratosis without perivascular infiltration lymphocyte. The baby was given breast feeding, antibiotic, hydrocortisone cream and olium olivarum. The prognosis of the baby is good.

  20. Alternation of regular and chaotic dynamics in a simple two-degree-of-freedom system with nonlinear inertial coupling.

    Science.gov (United States)

    Sigalov, G; Gendelman, O V; AL-Shudeifat, M A; Manevitch, L I; Vakakis, A F; Bergman, L A

    2012-03-01

    We show that nonlinear inertial coupling between a linear oscillator and an eccentric rotator can lead to very interesting interchanges between regular and chaotic dynamical behavior. Indeed, we show that this model demonstrates rather unusual behavior from the viewpoint of nonlinear dynamics. Specifically, at a discrete set of values of the total energy, the Hamiltonian system exhibits non-conventional nonlinear normal modes, whose shape is determined by phase locking of rotatory and oscillatory motions of the rotator at integer ratios of characteristic frequencies. Considering the weakly damped system, resonance capture of the dynamics into the vicinity of these modes brings about regular motion of the system. For energy levels far from these discrete values, the motion of the system is chaotic. Thus, the succession of resonance captures and escapes by a discrete set of the normal modes causes a sequence of transitions between regular and chaotic behavior, provided that the damping is sufficiently small. We begin from the Hamiltonian system and present a series of Poincaré sections manifesting the complex structure of the phase space of the considered system with inertial nonlinear coupling. Then an approximate analytical description is presented for the non-conventional nonlinear normal modes. We confirm the analytical results by numerical simulation and demonstrate the alternate transitions between regular and chaotic dynamics mentioned above. The origin of the chaotic behavior is also discussed.

  1. Asymptotics of decreasing solutions of coupled p-Laplacian systems in the framework of regular variation

    Czech Academy of Sciences Publication Activity Database

    Řehák, Pavel; Matucci, S.

    2014-01-01

    Roč. 193, č. 3 (2014), s. 837-858 ISSN 0373-3114 Institutional support: RVO:67985840 Keywords : decreasing solution * quasilinear system * Emden-Fowler system * Lane-Emden system * regular variation Subject RIV: BA - General Mathematics Impact factor: 1.065, year: 2014 http://link.springer.com/article/10.1007%2Fs10231-012-0303-9

  2. Lamellar-lamellar phase separation of phospholipid bilayers induced by salting-in/-out effects

    Energy Technology Data Exchange (ETDEWEB)

    Hishida, Mafumi [Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8501 (Japan); Seto, Hideki, E-mail: hideki.seto@kek.jp [KENS and CMRC, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan)

    2011-01-01

    The multilamellar structure of phospholipid bilayers is stabilized by the interactions between bilayers. Although the lamellar repeat distance is uniquely determined at the balance point of interactions between bilayers, a lamellar-lamellar phase separation, where the two phases with different lamellar repeat distance coexist, has been reported in a case of adding a salt to the aqueous solution of lipids. In order to understand the physical mechanism of the lamellar-lamellar phase separation, the effects of adding monovalent salt on the lamellar structure are studied by visual observation and by small-angle X-ray scattering. Further, a theoretical model based on the mean field theory is introduced and it is concluded that the salting-in and -out effects of lipid bilayers trigger the lamellar-lamellar phase separation.

  3. TU-CD-BRA-12: Coupling PET Image Restoration and Segmentation Using Variational Method with Multiple Regularizations

    Energy Technology Data Exchange (ETDEWEB)

    Li, L; Tan, S [Huazhong University of Science and Technology, Wuhan, Hubei (China); Lu, W [University of Maryland School of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: To propose a new variational method which couples image restoration with tumor segmentation for PET images using multiple regularizations. Methods: Partial volume effect (PVE) is a major degrading factor impacting tumor segmentation accuracy in PET imaging. The existing segmentation methods usually need to take prior calibrations to compensate PVE and they are highly system-dependent. Taking into account that image restoration and segmentation can promote each other and they are tightly coupled, we proposed a variational method to solve the two problems together. Our method integrated total variation (TV) semi-blind deconvolution and Mumford-Shah (MS) segmentation. The TV norm was used on edges to protect the edge information, and the L{sub 2} norm was used to avoid staircase effect in the no-edge area. The blur kernel was constrained to the Gaussian model parameterized by its variance and we assumed that the variances in the X-Y and Z directions are different. The energy functional was iteratively optimized by an alternate minimization algorithm. Segmentation performance was tested on eleven patients with non-Hodgkin’s lymphoma, and evaluated by Dice similarity index (DSI) and classification error (CE). For comparison, seven other widely used methods were also tested and evaluated. Results: The combination of TV and L{sub 2} regularizations effectively improved the segmentation accuracy. The average DSI increased by around 0.1 than using either the TV or the L{sub 2} norm. The proposed method was obviously superior to other tested methods. It has an average DSI and CE of 0.80 and 0.41, while the FCM method — the second best one — has only an average DSI and CE of 0.66 and 0.64. Conclusion: Coupling image restoration and segmentation can handle PVE and thus improves tumor segmentation accuracy in PET. Alternate use of TV and L2 regularizations can further improve the performance of the algorithm. This work was supported in part by National Natural

  4. Structural perfection of directionally solidified lamellar eutectics

    International Nuclear Information System (INIS)

    Attallah, T.; Gurzleski, J.E.

    1976-01-01

    The mechanisms for the formation of faults in lamellar eutectics are reviewed, and it is postulated that faults play several roles in eutectic freezing with their exact importance depending on the specific alloy system and the growth conditions. Faults are not the cause of lamellar spiralling although they are necessary for it to occur. Lamellar spiralling is found to occur only when the crystallographic orientations of the two eutectic phases lead to a growth component normal to the lamellar plane, and although some systems such as Pb-Sn normally spiral it is possible for them to achieve orientation relationships where no spiralling occurs

  5. Relativistic nuclear magnetic resonance J-coupling with ultrasoft pseudopotentials and the zeroth-order regular approximation

    International Nuclear Information System (INIS)

    Green, Timothy F. G.; Yates, Jonathan R.

    2014-01-01

    We present a method for the first-principles calculation of nuclear magnetic resonance (NMR) J-coupling in extended systems using state-of-the-art ultrasoft pseudopotentials and including scalar-relativistic effects. The use of ultrasoft pseudopotentials is allowed by extending the projector augmented wave (PAW) method of Joyce et al. [J. Chem. Phys. 127, 204107 (2007)]. We benchmark it against existing local-orbital quantum chemical calculations and experiments for small molecules containing light elements, with good agreement. Scalar-relativistic effects are included at the zeroth-order regular approximation level of theory and benchmarked against existing local-orbital quantum chemical calculations and experiments for a number of small molecules containing the heavy row six elements W, Pt, Hg, Tl, and Pb, with good agreement. Finally, 1 J(P-Ag) and 2 J(P-Ag-P) couplings are calculated in some larger molecular crystals and compared against solid-state NMR experiments. Some remarks are also made as to improving the numerical stability of dipole perturbations using PAW

  6. Precipitation of lamellar gold nanocrystals in molten polymers

    International Nuclear Information System (INIS)

    Palomba, M.; Carotenuto, G.

    2016-01-01

    Non-aggregated lamellar gold crystals with regular shape (triangles, squares, pentagons, etc.) have been produced by thermal decomposition of gold chloride (AuCl) molecules in molten amorphous polymers (polystyrene and poly(methyl methacrylate)). Such covalent inorganic gold salt is high soluble into non-polar polymers and it thermally decomposes at temperatures compatible with the polymer thermal stability, producing gold atoms and chlorine radicals. At the end of the gold precipitation process, the polymer matrix resulted chemically modified because of the partial cross-linking process due to the gold atom formation reaction.

  7. Spontaneous subconjunctival abscess in congenital lamellar ichthyosis

    Directory of Open Access Journals (Sweden)

    Shivanand C Bubanale

    2018-01-01

    Full Text Available Congenital lamellar ichthyosis is an autosomal recessive, heterogeneous disorder presenting at birth with generalized skin involvement. The most common ophthalmic manifestation noted is bilateral ectropion of the lower eyelids. A 1-month-old female neonate, the second born of a nonconsanguineous marriage, presented with 4 days' history of redness, discharge, and swelling in the right eye. There was severe right upper eyelid ectropion, conjunctival injection, chemosis, a subconjunctival mass on the temporal bulbar conjunctiva spontaneously draining pus and corneal haze. The anterior chamber, iris, lens and fundus appeared normal. Congenital lamellar ichthyosis was suspected because of scaling and excessive dryness of the entire body. The occurrence of a spontaneous subconjunctival abscess is not known in lamellar ichthyosis. We thus report the management of a rare case of unilateral upper eyelid ectropion, subconjunctival abscess with orbital cellulitis in congenital lamellar ichthyosis.

  8. Updating the lamellar hypothesis of hippocampal organization

    Directory of Open Access Journals (Sweden)

    Robert S Sloviter

    2012-12-01

    Full Text Available In 1971, Andersen and colleagues proposed that excitatory activity in the entorhinal cortex propagates topographically to the dentate gyrus, and on through a trisynaptic circuit lying within transverse hippocampal slices or lamellae [Andersen, Bliss, and Skrede. 1971. Lamellar organization of hippocampal pathways. Exp Brain Res 13, 222-238]. In this way, a relatively simple structure might mediate complex functions in a manner analogous to the way independent piano keys can produce a nearly infinite variety of unique outputs. The lamellar hypothesis derives primary support from the lamellar distribution of dentate granule cell axons (the mossy fibers, which innervate dentate hilar neurons and area CA3 pyramidal cells and interneurons within the confines of a thin transverse hippocampal segment. Following the initial formulation of the lamellar hypothesis, anatomical studies revealed that unlike granule cells, hilar mossy cells, CA3 pyramidal cells, and Layer II entorhinal cells all form axonal projections that are more divergent along the longitudinal axis than the clearly lamellar mossy fiber pathway. The existence of pathways with translamellar distribution patterns has been interpreted, incorrectly in our view, as justifying outright rejection of the lamellar hypothesis [Amaral and Witter. 1989. The three-dimensional organization of the hippocampal formation: a review of anatomical data. Neuroscience 31, 571-591]. We suggest that the functional implications of longitudinally-projecting axons depend not on whether they exist, but on what they do. The observation that focal granule cell layer discharges normally inhibit, rather than excite, distant granule cells suggests that longitudinal axons in the dentate gyrus may mediate "lateral" inhibition and define lamellar function, rather than undermine it. In this review, we attempt a reconsideration of the evidence that most directly impacts the physiological concept of hippocampal lamellar

  9. Congenital lamellar ichthyosis, a case report.

    OpenAIRE

    Joaquín Saavedra D.; María José Sierralta S.; Cristian Saavedra D; Vanesa Rivera C; Francisco Cerda C.

    2014-01-01

    ABSTRACT INTRODUCTION: Lamellar Ichthyosis is a rare skin diseases belonging to the Group of the so-called genodermatoses. It is a form of congenital ichthyosis evident at birth. CASE REPORT: Male neonate, born at 36 weeks of gestation via cesarian section, appropriate for gestational age and Apgar Score 8. Nonconsanguineous parents. Affected brother with Ichthyosis lamellar. Is hospitalized in the Neonatal Intermediary Care Unit of the Hospital of San Fernando due to ...

  10. Analytic theory of soft x-ray diffraction by lamellar multilayer gratings

    NARCIS (Netherlands)

    Kozhevnikov, I.V.; van der Meer, R.; Bastiaens, Hubertus M.J.; Boller, Klaus J.; Bijkerk, Frederik

    2011-01-01

    An analytic theory describing soft x-ray diffraction by Lamellar Multilayer Gratings (LMG) has been developed. The theory is derived from a coupled waves approach for LMGs operating in the single-order regime, where an incident plane wave can only excite a single diffraction order. The results from

  11. Dynamical mean-field approximation to small-world networks of spiking neurons: From local to global and/or from regular to random couplings

    International Nuclear Information System (INIS)

    Hasegawa, Hideo

    2004-01-01

    By extending a dynamical mean-field approximation previously proposed by the author [H. Hasegawa, Phys. Rev. E 67, 041903 (2003)], we have developed a semianalytical theory which takes into account a wide range of couplings in a small-world network. Our network consists of noisy N-unit FitzHugh-Nagumo neurons with couplings whose average coordination number Z may change from local (Z<< N) to global couplings (Z=N-1) and/or whose concentration of random couplings p is allowed to vary from regular (p=0) to completely random (p=1). We have taken into account three kinds of spatial correlations: the on-site correlation, the correlation for a coupled pair, and that for a pair without direct couplings. The original 2N-dimensional stochastic differential equations are transformed to 13-dimensional deterministic differential equations expressed in terms of means, variances, and covariances of state variables. The synchronization ratio and the firing-time precision for an applied single spike have been discussed as functions of Z and p. Our calculations have shown that with increasing p, the synchronization is worse because of increased heterogeneous couplings, although the average network distance becomes shorter. Results calculated by our theory are in good agreement with those by direct simulations

  12. Laser thermokeratoplasty after lamellar corneal cutting.

    Science.gov (United States)

    Ismail, M M; Pérez-Santonja, J J; Alió, J L

    1999-02-01

    To evaluate the effect of laser thermokeratoplasty (LTK) in eyes that previously had a lamellar corneal cut. University of Al-Azhar, Cairo, Egypt, and Instituto Oftalmológico de Alicante, Spain. In 15 eyes (10 patients), noncontact LTK was applied 6 to 8 weeks after a lamellar corneal cut had been made. Central pachymetry, keratometry, and videokeratography were performed and uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest and cycloplegic refractions measured before and 1, 6, 12, and 18 months after LTK. Mean follow-up was 19.13 months. Mean refraction was +5.93 diopters (D) +/- 1.9 (SD) before LTK and -0.43 +/- 1.5 D at 1 month, +1.63 +/- 1.6 D at 6 months, 1.91 +/- 1.41 at 12 months, and +2.01 +/- 1.5 D at the end of the study. Total regression did not occur in any case. Mean BSCVA before LTK was 0.66 +/- 0.2, and spontaneous visual acuity at the end of the study was 0.58 +/- 0.18. No patient lost any lines of preoperative BSCVA. There was no significant difference between the results at 12 months and at the end of the study. Corneal lamellar cutting appeared to improve the magnitude of the refractive effect of noncontact LTK and to decrease the amount of regression.

  13. A Case Report of Ichthyosis Lamellar Syndrome

    Directory of Open Access Journals (Sweden)

    Gh. Eshghi

    2014-04-01

    Full Text Available Introduction: Ichthyosis lamellar syndrome is a rare genodermatosis and in most families is inherited as an autosomal recessive trait because of transglutaminase-1 deficiency. Case Report: Our patient was a 6 year old girl and she was the result of consanguinity. She had large plate-like scales. The scales had mosaic-like pattern and erythroderma was absent. Tautness of her facial skin was associated with ectropion and eclabion and hypoplasia of auricular cartilages. She had scarring alopecia because of taut skin (specially at the periphery of scalp. She also had palmoplantar keratoderma and secondary nail dystrophy and thanked nails. Her parents also gave us the history of heat intolerance and it is because of interaepi-dermal constriction of sweat ducts. Our patient had the history of recurrent ear infections and it is because of accumulation of scales in the external ear. Conclusion: Our patient underwent a biopsy and based on our clinical findings her diagnosis was lamellar ichthyosis. (Sci J Hamadan Univ Med Sci 2014; 21 (1:76-79

  14. Adsorption of dimeric surfactants in lamellar silicates

    Energy Technology Data Exchange (ETDEWEB)

    Balcerzak, Mateusz; Pietralik, Zuzanna [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Domka, Ludwik [Department of Metalorganic Chemistry, Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań (Poland); Skrzypczak, Andrzej [Institute of Chemical Technology, Poznań University of Technology, Berdychowo 4, 60-965 Poznań (Poland); Kozak, Maciej, E-mail: mkozak@amu.edu.pl [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

    2015-12-01

    Highlights: • The intercalation of dimeric surfactants changed the morphology of MMT samples. • XRD indicated structures formed by surfactant molecules in interlayer space. • The four-step thermal decomposition of dimeric surfactant, confirms intercalation. - Abstract: The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay – hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1′-(1,4-butanediyl)bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d{sub 001}) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH{sub 2} and CH{sub 3} groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.

  15. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

    NARCIS (Netherlands)

    van Dooren, Bart T. H.; Mulder, Paul G. H.; Nieuwendaal, Carla P.; Beekhuis, W. Houdijn; Melles, Gerrit R. J.

    2004-01-01

    To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy was performed to

  16. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

    NARCIS (Netherlands)

    Van Dooren, BTH; Mulder, PGH; Nieuwendaal, CP; Beekhuis, WH; Melles, GRJ

    PURPOSE: To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. METHODS: In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy

  17. [Indications and surgical approach for lamellar macular holes and pseudoholes].

    Science.gov (United States)

    Haritoglou, C; Schumann, R G

    2017-12-01

    This article presents a discussion on the indications for surgical interventions of lamellar macular holes and pseudoholes. What are the criteria for deciding on the surgical intervention for lamellar macular holes and pseudoholes? The article is based on a literature search in PubMed RESULTS: Lamellar macular holes and pseudoholes are subdivided into degenerative and tractive alterations. Both entities are associated with relatively specific morphological and functional criteria, which correlate with the expected functional and morphological results of the surgical intervention. Patients with pseudoholes therefore profit more from a surgical intervention because alterations to the outer retina are less pronounced in these cases. The indications for surgery of lamellar macular holes and pseudoholes are established by the type of lamellar defect and the morphological and functional alterations associated with this condition.

  18. Self-consistent theory of steady-state lamellar solidification in binary eutectic systems

    International Nuclear Information System (INIS)

    Nash, G.E.; Glicksman, M.E.

    1976-01-01

    The potential theoretic methods developed recently at NRL for solving the diffusion equation are applied to the free-boundary problem describing lamellar eutectic solidification. Using these techniques, the original boundary value problem is reduced to a set of coupled integro-differential equations for the shape of the solid/liquid interface and various quantities defined on the interface. The behavior of the solutions is discussed in a qualitative fashion, leading to some interesting inferences regarding the nature of the eutectic solidification process. Using the information obtained from the analysis referred to above, an approximate theory of the lamellar-rod transition is formulated. The predictions of the theory are shown to be in qualitative agreement with experimental observations of this transition. In addition, a simplified version of the general integro-differential equations is developed and is used to assess the effect of interface curvature on the interfacial solute concentrations, and to check the new theory for consistency with experiment

  19. Extended constitutive laws for lamellar phases

    Directory of Open Access Journals (Sweden)

    Chi-Deuk Yoo

    2013-10-01

    Full Text Available Classically, stress and strain rate in linear viscoelastic materials are related by a constitutive relationship involving the viscoelastic modulus G(t. The same constitutive law, within Linear Response Theory, relates currents of conserved quantities and gradients of existing conjugate variables, and it involves the autocorrelation functions of the currents in equilibrium. We explore the consequences of the latter relationship in the case of a mesoscale model of a block copolymer, and derive the resulting relationship between viscous friction and order parameter diffusion that would result in a lamellar phase. We also explicitly consider in our derivation the fact that the dissipative part of the stress tensor must be consistent with the uniaxial symmetry of the phase. We then obtain a relationship between the stress and order parameter autocorrelation functions that can be interpreted as an extended constitutive law, one that offers a way to determine them from microscopic experiment or numerical simulation.

  20. Preparation of textural lamellar tin deposits via electrodeposition

    Science.gov (United States)

    Wen, Xiaoyu; Pan, Xiaona; Wu, Libin; Li, Ruinan; Wang, Dan; Zhang, Jinqiu; Yang, Peixia

    2017-06-01

    Lamellar tin deposits were prepared by galvanostatical electroplating from the aqueous acidic-sulfate bath, with gelatin and benzalacetone dissolved in ethanol (ABA+EtOH) as additive, and their morphologies were investigated by scanning electron microscopy. Cathodic polarization curves revealed that the absorbability of ABA+EtOH on the cathode surface was higher than that of gelatin. X-ray diffraction analysis indicated preferred orientations of tin growth led to the formation of lamellar structure and distortion of tin lattice. The growth mechanism of lamellar tin was also discussed.

  1. A structural study of lamellar phases formed by nucleoside-functionalized lipids

    Energy Technology Data Exchange (ETDEWEB)

    Berti, D.; Fratini, E.; Baglioni, P. [Department of Chemistry and CSGI, University of Florence, Via G. Capponi 9, 50121 Florence (Italy); Dante, S.; Hauss, T. [Berlin Neutron Scattering Center, Hahn Meitner Institut, Glienicker Strasse 100, Wannsee, 14109 Berlin (Germany)

    2002-07-01

    We report a neutron-scattering investigation of lamellar phases formed by novel phospholipids bearing nucleosides at the polar-head-group region. These nucleolipids can interact through stacking and H-bond interactions, following a pattern that resembles base-base coupling in natural nucleic acids (DNA, RNA), i.e. they have similar recognition properties. Bilayer stacks formed of DPP-adenosine, DPP-uridine and their 1:1 mixture were investigated after equilibration in a 98% relative humidity atmosphere. The DPP-adenosine spectrum can be accounted for (in analogy to DPPC) by a lamellar phase with a smectic period of about 60 A. DPP-uridine displays a not so straightforward behavior that we have tentatively ascribed to the coexistence of lamellae with different smectic periods. In the 1:1 mixture the lamellar mesophase of DPP-uridine is retained, suggesting a specific interaction of the uridine polar-head group with the adenosine moiety of DPP-adenosine. It should be stressed that this behavior can be considered as an indication of the recognition process occurring at the polar-head-group region of the mixed phospholiponucleoside membrane. (orig.)

  2. A structural study of lamellar phases formed by nucleoside-functionalized lipids

    CERN Document Server

    Berti, D; Baglioni, P; Dante, S; Hauss, T

    2002-01-01

    We report a neutron-scattering investigation of lamellar phases formed by novel phospholipids bearing nucleosides at the polar-head-group region. These nucleolipids can interact through stacking and H-bond interactions, following a pattern that resembles base-base coupling in natural nucleic acids (DNA, RNA), i.e. they have similar recognition properties. Bilayer stacks formed of DPP-adenosine, DPP-uridine and their 1:1 mixture were investigated after equilibration in a 98% relative humidity atmosphere. The DPP-adenosine spectrum can be accounted for (in analogy to DPPC) by a lamellar phase with a smectic period of about 60 A. DPP-uridine displays a not so straightforward behavior that we have tentatively ascribed to the coexistence of lamellae with different smectic periods. In the 1:1 mixture the lamellar mesophase of DPP-uridine is retained, suggesting a specific interaction of the uridine polar-head group with the adenosine moiety of DPP-adenosine. It should be stressed that this behavior can be considere...

  3. Lamellar ichthyosis (collodian baby with severe bilateral ectropion

    Directory of Open Access Journals (Sweden)

    Boparai M

    1988-01-01

    Full Text Available A case of lamellar ichthyosis (collodian baby, is being reported. Skin biopsy has confirmed the diagnosis. Severe bilateral ectropion of thee eyelids was the prominent feature. Management of such cases has been briefly discussed.

  4. Adaptive regularization

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Rasmussen, Carl Edward; Svarer, C.

    1994-01-01

    Regularization, e.g., in the form of weight decay, is important for training and optimization of neural network architectures. In this work the authors provide a tool based on asymptotic sampling theory, for iterative estimation of weight decay parameters. The basic idea is to do a gradient desce...

  5. Oligosaccharides and glycolipids addition in charged lamellar phases

    International Nuclear Information System (INIS)

    Ricoul, F.

    1997-01-01

    The aim of this work is to study the addition of oligosaccharides and glycolipids in lamellar phases of the cationic surfactant DDAB (di-dodecyl-dimethyl-ammonium bromide). Two steps have been followed: the determination of phases prisms and the thermodynamic interpretation in terms of molecular interactions. In order to characterize these systems, two new experimental small angle scattering methods have been perfected: 1) a neutron scattering contrast variation method which allows to study the adsorption of aqueous solution in bilayers and 2) a capillary concentration gradient method to establish directly and quantitatively the phases diagrams of ternary systems by X rays scattering. It has been pointed out that the oligosaccharides induce a depletion attractive force on the lamellar-lamellar equilibrium of the DDAB when they are excluded of the most concentrated phase. For the two studied glycolipids: 2-O lauroyl-saccharose and N-lauroyl N-nonyl lactitol, the ternary phase diagrams water-DDAB-glycolipid have been established in terms of temperature. Critical points at ambient temperature have been given. The osmotic pressure in concentrated lamellar phases has been measured. It has been shown that glycolipids increase the hydration repulsion at short distance and that the electrostatic repulsion is outstanding and unchanged at high distance if there is at less 1 mole percent of ionic surfactant. In a dilute solution, glycolipids decrease the maximum swelling of lamellar phases, with a competition between the lamellar phase and the micellae dilute phase for water. (O.M.)

  6. Regularized unfolding of jet cross sections in deep-inelastic ep scattering at HERA and determination of the strong coupling constant

    Energy Technology Data Exchange (ETDEWEB)

    Britzger, Daniel Andreas

    2013-10-15

    In this thesis double-differential cross sections for jet production in neutral current deep-inelastic e{sup {+-}}p scattering (DIS) are presented at the center-of-mass energy of {radical}(s)=319 GeV, and in the kinematic range of the squared four-momentum transfer 150< Q{sup 2}<15 000 GeV{sup 2} and the inelasticity 0.2regularized unfolding procedure which features a correct propagation of the statistical uncertainty. The matrix based unfolding corrects the neutral current DIS, the inclusive jet, the dijet and the trijet measurements simultaneously, and it considers migrations in up to eight variables. The simultaneous unfolding enables to constrain contributions from jet multiplicities differing between detector and hadron level using the neutral current DIS kinematics of such events. Furthermore, jet cross sections normalized to the inclusive neutral current DIS cross section and ratios of jet cross sections are obtained, since the statistical correlations between these observables are known. The jet cross sections are used to determine the strong coupling constant {alpha}{sub s}(M{sub Z}) at the scale of the mass of the Z{sup 0} boson in the framework of perturbative quantum chromodynamics in next-to-leading order. Values are derived separately for the absolute

  7. Anatomical and Functional Results of Lamellar Macular Holes Surgery.

    Science.gov (United States)

    Papadopoulou, D; Donati, G; Mangioris, G; Pournaras, C J

    2016-04-01

    To determine the long-term surgical findings and outcomes after vitrectomy for symptomatic lamellar macular holes. We studied 28 patients with lamellar macular holes and central visual loss or distortion. All interventions were standard 25 G vitrectomy with membranectomy of the internal limiting membrane (ILM), peeling and gas tamponade with SF6 20 %. Operations were performed by a single experienced surgeon within the last 3 years. Best corrected visual acuity and optical coherence tomography appearance were determined preoperatively and postoperatively. Following the surgical procedure, all macular holes were closed; however, in 3 eyes, significant foveal thinning was associated with changes in the retinal pigment epithelium changes. The mean best-corrected visual acuity improved postoperatively in the majority of the patients (n: 21, mean 0.3 logMAR), stabilised in 4 patients and decreased in 3 patients (mean 0.4 logMAR). Spectral Domain-Optical coherence tomography (SD-OCT) showed resolution of the lamellar lesion and improved macular contour in all cases. We demonstrated improvement in postoperative vision and the anatomical reconstruction of the anatomical contour of the fovea in most eyes with symptomatic lamellar holes. These findings indicate that vitrectomy, membranectomy and ILM peeling with gas tamponade is a beneficial treatment of symptomatic lamellar macular holes. Georg Thieme Verlag KG Stuttgart · New York.

  8. First principles calculations of interstitial and lamellar rhenium nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Soto, G., E-mail: gerardo@cnyn.unam.mx [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km 107 Carretera Tijuana-Ensenada, Ensenada Baja California (Mexico); Tiznado, H.; Reyes, A.; Cruz, W. de la [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km 107 Carretera Tijuana-Ensenada, Ensenada Baja California (Mexico)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The possible structures of rhenium nitride as a function of composition are analyzed. Black-Right-Pointing-Pointer The alloying energy is favorable for rhenium nitride in lamellar arrangements. Black-Right-Pointing-Pointer The structures produced by magnetron sputtering are metastable variations. Black-Right-Pointing-Pointer The structures produced by high-pressure high-temperature are stable configurations. Black-Right-Pointing-Pointer The lamellar structures are a new category of interstitial dissolutions. - Abstract: We report here a systematic first principles study of two classes of variable-composition rhenium nitride: i, interstitial rhenium nitride as a solid solution and ii, rhenium nitride in lamellar structures. The compounds in class i are cubic and hexagonal close-packed rhenium phases, with nitrogen in the octahedral and tetrahedral interstices of the metal, and they are formed without changes to the structure, except for slight distortions of the unit cells. In the compounds in class ii, by contrast, the nitrogen inclusion provokes stacking faults in the parent metal structure. These faults create trigonal-prismatic sites where the nitrogen residence is energetically favored. This second class of compounds produces lamellar structures, where the nitrogen lamellas are inserted among multiple rhenium layers. The Re{sub 3}N and Re{sub 2}N phases produced recently by high-temperature and high-pressure synthesis belong to this class. The ratio of the nitrogen layers to the rhenium layers is given by the composition. While the first principle calculations point to higher stability for the lamellar structures as opposed to the interstitial phases, the experimental evidence presented here demonstrates that the interstitial classes are synthesizable by plasma methods. We conclude that rhenium nitrides possess polymorphism and that the two-dimensional lamellar structures might represent an emerging class of materials

  9. First principles calculations of interstitial and lamellar rhenium nitrides

    International Nuclear Information System (INIS)

    Soto, G.; Tiznado, H.; Reyes, A.; Cruz, W. de la

    2012-01-01

    Highlights: ► The possible structures of rhenium nitride as a function of composition are analyzed. ► The alloying energy is favorable for rhenium nitride in lamellar arrangements. ► The structures produced by magnetron sputtering are metastable variations. ► The structures produced by high-pressure high-temperature are stable configurations. ► The lamellar structures are a new category of interstitial dissolutions. - Abstract: We report here a systematic first principles study of two classes of variable-composition rhenium nitride: i, interstitial rhenium nitride as a solid solution and ii, rhenium nitride in lamellar structures. The compounds in class i are cubic and hexagonal close-packed rhenium phases, with nitrogen in the octahedral and tetrahedral interstices of the metal, and they are formed without changes to the structure, except for slight distortions of the unit cells. In the compounds in class ii, by contrast, the nitrogen inclusion provokes stacking faults in the parent metal structure. These faults create trigonal-prismatic sites where the nitrogen residence is energetically favored. This second class of compounds produces lamellar structures, where the nitrogen lamellas are inserted among multiple rhenium layers. The Re 3 N and Re 2 N phases produced recently by high-temperature and high-pressure synthesis belong to this class. The ratio of the nitrogen layers to the rhenium layers is given by the composition. While the first principle calculations point to higher stability for the lamellar structures as opposed to the interstitial phases, the experimental evidence presented here demonstrates that the interstitial classes are synthesizable by plasma methods. We conclude that rhenium nitrides possess polymorphism and that the two-dimensional lamellar structures might represent an emerging class of materials within binary nitride chemistry.

  10. Microstructures and mechanical properties of directionally solidified Ni-25%Si full lamellar in situ composites

    International Nuclear Information System (INIS)

    Zhang, Binggang; Li, Xiaopeng; Wang, Ting; Liu, Zheng

    2016-01-01

    Directional solidification experiments have been performed on Ni-25 at% Si alloy using electron beam floating zone method. A fully regular eutectic microstructures consisting of Ni, γ-Ni 31 Si 12 and β 1 -Ni 3 Si have been obtained. The influences of the directional solidification rate on the microstructures and properties of the full lamellar structures have been studied. The results show that the relationship between the mean interphase spacing (λ) and withdrawal rate (v) meets λ=29.9v −0.65 . The hardness increases with the increasing of growth rate (v) and decreasing of the interlamellar spacing (λ) which meets the relationship of H V =445.2v 0.14 and H V =910λ −0.21 . The maximum compressive strength, 2576 MPa, for DS samples is obtained by 10 mm/h. The average fracture toughness value found for 5 mm/h, 7 mm/h, 10 mm/h is 28.3 MPa m 1/2 , 29.1 MPa m 1/2 and 35.9 MPa m 1/2 , respectively. The crack bridging and crack deflection/interface debonding are the main toughening mechanism of Ni-25 at% Si with full lamellar structures.

  11. Analysis of Lamellar Structures with Application of Generalized Functions

    Directory of Open Access Journals (Sweden)

    Kipiani Gela

    2016-12-01

    Full Text Available Theory of differential equations in respect of the functional area is based on the basic concepts on generalized functions and splines. There are some basic concepts related to the theory of generalized functions and their properties are considered in relation to the rod systems and lamellar structures. The application of generalized functions gives the possibility to effectively calculate step-variable stiffness lamellar structures. There are also widely applied structures, in that several in which a number of parallel load bearing layers are interconnected by discrete-elastic links. For analysis of system under study, such as design diagrams, there are applied discrete and discrete-continual models.

  12. Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser.

    Science.gov (United States)

    Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders; Søndergaard, Anders

    2012-01-01

    Posterior lamellar grafting of the cornea has become the preferred technique for treatment of corneal endothelial dysfunction. Posterior lamellar grafts are usually cut by a micro-keratome or a femto-second laser after the epithelial side of the donor cornea has been applanated. This approach often results in variable central graft thickness in different grafts and an increase in graft thickness towards the periphery in every graft. The purpose of this study was to evaluate if posterior lamellar grafts can be prepared from the endothelial side by a femto-second laser, resulting in reproducible, thin grafts of even thickness. A CZM 500 kHz Visumax femto-second laser was used. Organ cultured donor grafts were mounted in an artifical anterior chamber with the endothelial side up and out. Posterior grafts of 7.8 mm diameter and 130 micron thickness were prepared by femto-second laser cutting. A standard DSAEK procedure was performed in 10 patients with Fuchs endothelial dystrophy. Patients were followed-up regularly and evaluated by measurement of complications, visual acuity, corneal thickness (Pentacam HR), and endothelial cell density. Femto-laser cutting of grafts and surgery was uncomplicated. Rebubbling was necessary in 5 of 10 cases (normally only in 1 of 20 cases). All grafts were attached and cleared up during the first few weeks. After six months, the average visual acuity was 0.30 (range: 0.16 to 0.50), corneal thickness was 0.58 mm (range 0.51 to 0.63), and endothelial cell density was 1.570 per sq. mm (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months with satisfying endothelial cell counts. Poor visual acuity caused by interface scatter was observed in most patients. Femto-second laser cutting parameters needs to be optimised to

  13. Extensive regularization of the coupled cluster methods based on the generating functional formalism: Application to gas-phase benchmarks and to the SN2 reaction of CHCl3 and OH- in water

    International Nuclear Information System (INIS)

    Kowalski, Karol; Valiev, Marat

    2009-01-01

    The recently introduced energy expansion based on the use of generating functional (GF) [K. Kowalski and P. D. Fan, J. Chem. Phys. 130, 084112 (2009)] provides a way of constructing size-consistent noniterative coupled cluster (CC) corrections in terms of moments of the CC equations. To take advantage of this expansion in a strongly interacting regime, the regularization of the cluster amplitudes is required in order to counteract the effect of excessive growth of the norm of the CC wave function. Although proven to be efficient, the previously discussed form of the regularization does not lead to rigorously size-consistent corrections. In this paper we address the issue of size-consistent regularization of the GF expansion by redefining the equations for the cluster amplitudes. The performance and basic features of proposed methodology are illustrated on several gas-phase benchmark systems. Moreover, the regularized GF approaches are combined with quantum mechanical molecular mechanics module and applied to describe the S N 2 reaction of CHCl 3 and OH - in aqueous solution.

  14. Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus

    Directory of Open Access Journals (Sweden)

    Spadea L

    2012-11-01

    Full Text Available Leopoldo Spadea,1 Marino Paroli21University of L’Aquila, Department of Biotechnological and Applied Clinical Sciences, Eye Clinic, L’Aquila, 2La Sapienza University, Department of Biotechnology and Medical-Surgical Sciences, Latina, ItalyBackground: The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK and prophylactic corneal collagen crosslinking (CXL for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus.Methods: The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK, and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50. After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization and corneal CXL induced by riboflavin-ultraviolet A.Results: After a mean 15 ± 6.5 (range 6–24 months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1–10. No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0 D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8–8.9 D. All the corneas remained clear (haze < 1.Conclusion: The combination of customized PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.Keywords: corneal collagen crosslinking, excimer laser-assisted lamellar keratoplasty, photorefractive keratectomy

  15. Structural studies of lamellar surfactant systems under shear

    DEFF Research Database (Denmark)

    Mortensen, K.

    2001-01-01

    Recent experimental studies on concentrated surfactant systems are reviewed. Particular attention is focused on the transformation from planar lamellar sheets to multilamellar vesicles. It is discussed whether both of these states are thermodynamic stable, or if the MLV is an artifact of shear in...

  16. Polynomial modal analysis of lamellar diffraction gratings in conical mounting.

    Science.gov (United States)

    Randriamihaja, Manjakavola Honore; Granet, Gérard; Edee, Kofi; Raniriharinosy, Karyl

    2016-09-01

    An efficient numerical modal method for modeling a lamellar grating in conical mounting is presented. Within each region of the grating, the electromagnetic field is expanded onto Legendre polynomials, which allows us to enforce in an exact manner the boundary conditions that determine the eigensolutions. Our code is successfully validated by comparison with results obtained with the analytical modal method.

  17. Synthesis and characterization of a lamellar hydroxyapatite/DNA nanohybrid

    Energy Technology Data Exchange (ETDEWEB)

    Zuo Guifu; Wan Yizao; Meng Xianguang [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhao Qing [School of Agriculture and Bioengineering, Tianjin University, Tianjin 300072 (China); Ren Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Jia Shiru [Key Laboratory of Industrial Microbiology, Ministry of Education, Tianjin University of Science and Technology, 29, 13th Street, TEDA, Tianjin 300457 (China); Wang Jiehua, E-mail: gfzuo@tju.edu.cn [School of Agriculture and Bioengineering, Tianjin University, Tianjin 300072 (China)

    2011-04-15

    Research highlights: {yields} A lamellar hydroxyapatite (HAp)/DNA nanohybrid was prepared as a novel gene delivering vector. {yields} Gel electrophoresis analysis confirmed that the lamellar HAp could protect DNA from degradation of DNase I. {yields} The protected DNA in the HAp/DNA nanohybrid could be recovered readily under acid conditions. - Abstract: Two-dimensional layered materials exhibit desired functionalities when being used as gene delivery materials. In this study, a novel gene delivering vector, lamellar hydroxyapatite (HAp)/DNA nanohybrid was prepared. The structure of HAp/DNA nanohybrid was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FT-IR) spectroscopy analysis revealed that ion-exchange occurred during the process. Gel electrophoresis analysis confirmed that the lamellar HAp could protect DNA from degradation of DNase I and the protected DNA could be recovered readily under acid conditions. Furthermore, the integrity of released DNA was confirmed by UV-vis spectra.

  18. Synthesis and characterization of a lamellar hydroxyapatite/DNA nanohybrid

    International Nuclear Information System (INIS)

    Zuo Guifu; Wan Yizao; Meng Xianguang; Zhao Qing; Ren Kaijing; Jia Shiru; Wang Jiehua

    2011-01-01

    Research highlights: → A lamellar hydroxyapatite (HAp)/DNA nanohybrid was prepared as a novel gene delivering vector. → Gel electrophoresis analysis confirmed that the lamellar HAp could protect DNA from degradation of DNase I. → The protected DNA in the HAp/DNA nanohybrid could be recovered readily under acid conditions. - Abstract: Two-dimensional layered materials exhibit desired functionalities when being used as gene delivery materials. In this study, a novel gene delivering vector, lamellar hydroxyapatite (HAp)/DNA nanohybrid was prepared. The structure of HAp/DNA nanohybrid was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FT-IR) spectroscopy analysis revealed that ion-exchange occurred during the process. Gel electrophoresis analysis confirmed that the lamellar HAp could protect DNA from degradation of DNase I and the protected DNA could be recovered readily under acid conditions. Furthermore, the integrity of released DNA was confirmed by UV-vis spectra.

  19. Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus.

    Science.gov (United States)

    Spadea, Leopoldo; Paroli, Marino

    2012-01-01

    The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK) and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus. The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK), and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50). After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A. After a mean 15 ± 6.5 (range 6-24) months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1-10). No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0) D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8-8.9) D. All the corneas remained clear (haze PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.

  20. Mechanisms of lamellar collagen formation in connective tissues.

    Science.gov (United States)

    Ghazanfari, Samaneh; Khademhosseini, Ali; Smit, Theodoor H

    2016-08-01

    The objective of tissue engineering is to regenerate functional tissues. Engineering functional tissues requires an understanding of the mechanisms that guide the formation and evolution of structure in the extracellular matrix (ECM). In particular, the three-dimensional (3D) collagen fiber arrangement is important as it is the key structural determinant that provides mechanical integrity and biological function. In this review, we survey the current knowledge on collagen organization mechanisms that can be applied to create well-structured functional lamellar tissues and in particular intervertebral disc and cornea. Thus far, the mechanisms behind the formation of cross-aligned collagen fibers in the lamellar structures is not fully understood. We start with cell-induced collagen alignment and strain-stabilization behavior mechanisms which can explain a single anisotropically aligned collagen fiber layer. These mechanisms may explain why there is anisotropy in a single layer in the first place. However, they cannot explain why a consecutive collagen layer is laid down with an alternating alignment. Therefore, we explored another mechanism, called liquid crystal phasing. While dense concentrations of collagen show such behavior, there is little evidence that the conditions for liquid crystal phasing are actually met in vivo. Instead, lysyl aldehyde-derived collagen cross-links have been found essential for correct lamellar matrix deposition. Furthermore, we suggest that supra-cellular (tissue-level) shear stress may be instrumental in the alignment of collagen fibers. Understanding the potential mechanisms behind the lamellar collagen structure in connective tissues will lead to further improvement of the regeneration strategies of functional complex lamellar tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Couplings

    Science.gov (United States)

    Stošić, Dušan; Auroux, Aline

    Basic principles of calorimetry coupled with other techniques are introduced. These methods are used in heterogeneous catalysis for characterization of acidic, basic and red-ox properties of solid catalysts. Estimation of these features is achieved by monitoring the interaction of various probe molecules with the surface of such materials. Overview of gas phase, as well as liquid phase techniques is given. Special attention is devoted to coupled calorimetry-volumetry method. Furthermore, the influence of different experimental parameters on the results of these techniques is discussed, since it is known that they can significantly influence the evaluation of catalytic properties of investigated materials.

  2. New regular black hole solutions

    International Nuclear Information System (INIS)

    Lemos, Jose P. S.; Zanchin, Vilson T.

    2011-01-01

    In the present work we consider general relativity coupled to Maxwell's electromagnetism and charged matter. Under the assumption of spherical symmetry, there is a particular class of solutions that correspond to regular charged black holes whose interior region is de Sitter, the exterior region is Reissner-Nordstroem and there is a charged thin-layer in-between the two. The main physical and geometrical properties of such charged regular black holes are analyzed.

  3. UNFOLDED REGULAR AND SEMI-REGULAR POLYHEDRA

    Directory of Open Access Journals (Sweden)

    IONIŢĂ Elena

    2015-06-01

    Full Text Available This paper proposes a presentation unfolding regular and semi-regular polyhedra. Regular polyhedra are convex polyhedra whose faces are regular and equal polygons, with the same number of sides, and whose polyhedral angles are also regular and equal. Semi-regular polyhedra are convex polyhedra with regular polygon faces, several types and equal solid angles of the same type. A net of a polyhedron is a collection of edges in the plane which are the unfolded edges of the solid. Modeling and unfolding Platonic and Arhimediene polyhedra will be using 3dsMAX program. This paper is intended as an example of descriptive geometry applications.

  4. Continuum-regularized quantum gravity

    International Nuclear Information System (INIS)

    Chan Huesum; Halpern, M.B.

    1987-01-01

    The recent continuum regularization of d-dimensional Euclidean gravity is generalized to arbitrary power-law measure and studied in some detail as a representative example of coordinate-invariant regularization. The weak-coupling expansion of the theory illustrates a generic geometrization of regularized Schwinger-Dyson rules, generalizing previous rules in flat space and flat superspace. The rules are applied in a non-trivial explicit check of Einstein invariance at one loop: the cosmological counterterm is computed and its contribution is included in a verification that the graviton mass is zero. (orig.)

  5. Magnetic properties of lamellar tetrataenite in Toluca iron meteorite

    International Nuclear Information System (INIS)

    Funaki, Minoru; Nagata, Takesi; Danon, J.

    1985-01-01

    Magnetic studies were conducted using lamellar tetrataenite extracted from the Toluca octahedrite by a diluted HCl etching technique. Natural remanent magnetization (NRM) in the lamellae is very stable against AF demagnetization and is quite intense, ranging from 2.58 to 37.42 x10 -2 emu/g. This NRM is completely demagnetized thermally at about 550 0 C. The most characteristic change in magnetic properties on heating to about 550 C 0 is a significant decrease in magnetic coercivity. This observation is consistent with the results obtained from chondrites. The paramagnetic component in lamellar tetrataenite, which is estimated by Moessbauer spectrum analyses, was not detected by conventional magnetic studies. (Author) [pt

  6. Insertion of anisotropic particles in lamellar surfactant phases

    International Nuclear Information System (INIS)

    Grillo, Isabelle

    1998-01-01

    We search for the interactions governing the possibility to mix organic and inorganic colloids. We use laponite, a synthetic anionic clay, made of 30 nm diameter and 1 nm thickness anisotropic disks. Three surfactant Systems, an anionic one (AOT), a cationic one (DDAB) and a nonionic one (C_1_2E_5) investigate three different cases of interaction forces. We establish experimentally the equilibrium phase diagrams and characterise the structure of these ternary Systems by SANS and SAXS experiments. We quantify the adsorption. An AOT bilayer surround the particle edges; an almost complete bilayer of DDAB and C_1_2E_5 is formed on the basal faces. SANS contrast variation experiments under controlled conditions along the adsorption isotherm of C_1_2E_5 allow to determine the average thickness of the adsorbed surfactant layer. In the monophasic lamellar domain, the particles stay between the membranes, when the spacing is larger than the particle thickness. In the biphasic domain, dense clay aggregates are in equilibrium with a lamellar phase, containing few amount of particles. They enter in the AOT bilayers when the space between the bilayers are smaller than 8 A. From the phase diagram and interaction forces study, three conditions of stability emerge: - an osmotic one: the osmotic lamellar pressure is higher or equal to the colloidal one. - an energetic one: the interaction energy between a particle and the surfactant bilayer is close to the particle energy in aqueous suspension. - an entropic one: particles should not inhibit the stabilising fluctuations of the lamellar phase. (author) [fr

  7. Oral manifestations of lamellar ichthyosis: A rare case report

    Directory of Open Access Journals (Sweden)

    Keerthi K Nair

    2016-01-01

    Full Text Available The ichthyoses are a heterogeneous group of disorders with both inherited and acquired forms. Autosomal recessive congenital ichthyosis (ARCI is a heterogeneous group of disorders that present at birth with the generalized involvement of skin without other systemic manifestations. Lamellar itchthyosis (LI is a nonsyndromic itchthyosis, which comes under the umbrella of ARCI. Little is only known about the oral manifestations of this disorder. We report a case of LI with oral manifestations.

  8. Lamellar Micelles - Mediated Synthesis of Nanoscale Thick Sheets of Titania

    Czech Academy of Sciences Publication Activity Database

    Klusoň, P.; Lusková, H.; Šolcová, Olga; Matějová, Lenka; Cajthaml, Tomáš

    2007-01-01

    Roč. 61, 14-15 (2007), s. 2931-2934 ISSN 0167-577X R&D Projects: GA ČR(CZ) GA104/04/0963; GA ČR(CZ) GD203/03/H140 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z50200510 Keywords : nanostructures * lamellar titania * templating Subject RIV: CA - Inorganic Chemistry Impact factor: 1.625, year: 2007

  9. Association between lamellar body count and respiratory distress in neonates

    International Nuclear Information System (INIS)

    Bahasadri, Shoreh; Changizi, Nasrin

    2005-01-01

    Assessment of fetal lung maturity by a simple and rapid test has a pivotal role in obstetric managements. Lack of modern laboratory techniques in our country made US investigate whether lamellar body count (Lb) can be applied efficiently in the evaluation of fetal lung maturity. Lamellar body count was assessed in 104 un spun amniotic fluid samples taken from pregnant women admitted at A kbar Aba di Hospital, Tehran, Iran between May 2003 and November 2003 whose fetuses were at risk for respiratory distress syndrome (RDS). Cut-off points for LBC were determined to evaluate the risk of RDS. Standard clinical and radiographic criteria were used to diagnose RDS. An LBC of less than 10,000 was 99.1% specific for lung immaturity (positive predictive value = 99.1%, negative predictive value = 83.5%). The LBCs of greater than 45,000 eliminates RDS (negative predictive value = 98.9%). Lamellar body count is an easy, rapid and cost-effective test to assess fetal lung maturity in high-risk fetuses. Using the cut-off points of 10,000 and 45,000, LBC can serve as the first screening test of fetal lung maturity. (author)

  10. Coordinate-invariant regularization

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1987-01-01

    A general phase-space framework for coordinate-invariant regularization is given. The development is geometric, with all regularization contained in regularized DeWitt Superstructures on field deformations. Parallel development of invariant coordinate-space regularization is obtained by regularized functional integration of the momenta. As representative examples of the general formulation, the regularized general non-linear sigma model and regularized quantum gravity are discussed. copyright 1987 Academic Press, Inc

  11. Regularized unfolding of jet cross sections in deep-inelastic ep scattering at HERA and determination of the strong coupling constant

    International Nuclear Information System (INIS)

    Britzger, Daniel Andreas

    2013-10-01

    In this thesis double-differential cross sections for jet production in neutral current deep-inelastic e ± p scattering (DIS) are presented at the center-of-mass energy of √(s)=319 GeV, and in the kinematic range of the squared four-momentum transfer 150 2 2 and the inelasticity 0.2 T -algorithm and are constrained to the pseudorapidity range -1.0 lab jet T jet T jet s (M Z ) at the scale of the mass of the Z 0 boson in the framework of perturbative quantum chromodynamics in next-to-leading order. Values are derived separately for the absolute and normalized jet cross section measurements. A higher sensitivity to α s (M Z ) is obtained in a simultaneous least-square-minimization procedure to the three jet cross sections, taking the statistical correlations and correlations due to other experimental uncertainties into account. The most precise value is obtained from all normalized jet cross sections, yielding α s (M Z )=0.1165±0.0008, which benefits from the high statistical precision of the inclusive jet measurement, the increased sensitivity to α s (M Z ) of the trijet cross section, and from the cancellation of normalization uncertainties. However, the value of the strong coupling constant is currently only determinable from this measurement with a precision of 3 to 4% due to the limited precision of the theoretical predictions at next-to-leading order.

  12. Precipitation kinetics of lamellar (γ) laths in a TiAl-base alloy

    International Nuclear Information System (INIS)

    Zhang, W.J.; Francesconi, L.; Evangelista, E.

    1997-01-01

    Titanium aluminide is a candidate material for high temperature applications. Although different types of microstructure have been produced in TiAl-base alloys, the fully-lamellar structure is currently regarded as the most attractive. This kind of microstructure can be characterized by the factors, namely, colony size, lamellar interspacing, the existence of Widmanstatten (secondary) laths, and the type of grain boundaries (smooth or interlocking). The objective of this paper is to examine the nucleation and growth kinetics of γ lamellar laths during continuous and isothermal cooling. These data are expected to benefit the understanding of the transformation mechanism and the design of lamellar TiAl microstructure for industrial application

  13. Complications and Management of Deep Anterior Lamellar Keratoplasty

    Directory of Open Access Journals (Sweden)

    Banu Torun Acar

    2014-10-01

    Full Text Available Objectives: To report the intraoperative and postoperative follow-up complications and management of these in deep anterior lamellar keratoplasty (DALK surgery. Materials and Methods: Two hundred eighty-four eyes of 252 patients followed up in our cornea clinic who underwent DALK using Anwar’s big-bubble technique with healthy Descemet’s membrane and endothelium were included in this study. Intraoperative and postoperative complications as well as the management and treatment of these complications were evaluated. Results: Big bubble was created in 220 (77.5% eyes of 284 eyes, and lamellar dissection was performed in 64 (22.5% eyes. Perforation occurred during trephination in 4 eyes, and the procedure was accomplished by penetrating keratoplasty (PK. Intraoperative microperforation occurred in 44 eyes. Perforation enlarged in 4 eyes and PK was performed. Operation was continued in 40 eyes with air injection into the anterior chamber. In postopertive follow-up period, double anterior chamber (DAC occurred in 32 of 40 eyes. DAC spontaneously regressed in 8 eyes, and air was given into the anterior chamber with a second surgical intervention in 24 eyes. DAC improved in 20 eyes. Four eyes underwent PK. Fungal keratitis evolved at the interface in one eye, because of no healing during the follow-up period, this eye underwent PK under antifungal therapy. Eyes with interface haze and Descemet’s membrane folds were followed. Conclusion: DALK is a difficult technique with a steep learning curve. In addition to the complications seen in PK, specific complications can occur in lamellar surgery. (Turk J Ophthalmol 2014; 44: 337-40

  14. Femtosecond laser-assisted deep anterior lamellar keratoplasty in phototherapeutic keratectomy versus the big-bubble technique in keratoconus

    Directory of Open Access Journals (Sweden)

    Jarbas Pereira de Macedo

    2018-05-01

    Full Text Available AIM: To compare the functional and anatomic results of femtosecond laser (FSL-assisted deep anterior lamellar keratoplasty (DALK associated with phototherapeutic keratectomy (PTK and FSL-assisted DALK performed using the big-bubble technique in keratoconus. METHODS: During the first phase of the study, an electron microscopy histopathology pilot study was conducted that included four unsuitable donor corneas divided into two groups: in FSL group, FSL lamellar cuts were performed on two corneas and in FSL+PTK group, PTK was performed at the stromal beds of two corneas after FSL lamellar cuts were made. During the second phase of the study, a randomized clinical trial was conducted that included two treatment groups of patients with keratoconus: group 1 (n=14 eyes underwent FSL-assisted DALK associated with PTK and group 2 (n=12 eyes underwent FSL-assisted DALK associated with the big-bubble technique. The main outcome measures were the postoperative visual acuity (VA and optical coherence tomography (OCT measurements, confocal microscopic findings, and contrast sensitivity. RESULTS: In the pilot study, histopathology showed a more regular stromal bed in the FSL+PTK group. In the clinical trial, group 1 had significantly worse best spectacle-corrected VA and contrast sensitivity (P<0.05 for both comparisons. The residual stromal bed measured by OCT was significantly (P<0.05 thicker in group 1. Confocal microscopy detected opacities only at the donor-receptor interface in group 1. CONCLUSION: Patients with keratoconus treated with FSL-assisted DALK performed using the big-bubble technique fare better than treated with FSL-assisted DALK associated with PTK.

  15. Hierarchical transport of nanoparticles in a lyotropic lamellar phase

    International Nuclear Information System (INIS)

    Kimura, Yasuyuki; Mori, Teppei; Yamamoto, Akira; Mizuno, Daisuke

    2005-01-01

    The dynamics of nanosized colloidal particles dispersed in a hyper-swollen lyotropic lamellar phase of a nonionic surfactant has been studied by ac electrophoretic light scattering and direct tracking of particles under a microscope. The frequency spectrum of electrophoretic mobility shows two relaxation processes. These are originated from the hindrance of free diffusion of particles by the interaction between membranes and particles. By direct tracking measurement, we find that particles jump from site to site where they stay for a long time. This trap-jump process greatly decreases the mobility at low frequencies

  16. Synthesis and characterization of lamellar aragonite with hydrophobic property

    International Nuclear Information System (INIS)

    Wang Chengyu; Xu Yang; Liu Yalan; Li Jian

    2009-01-01

    A novel and simple synthetic method for the preparation of hydrophobic lamellar aragonite has been developed. The crystallization of aragonite was conducted by the reaction of sodium carbonate with calcium chloride in the presence of sodium stearate. The resulting products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the contact angle. The results revealed that sodium stearate plays an important role in determining the structure and morphology of the sample. Besides, we have succeeded in surface modification of particles in situ at the same time. The contact angle of the modified aragonite reached 108.59 deg.

  17. Hybrid Technique of Lamellar Keratoplasty (DMEK-S

    Directory of Open Access Journals (Sweden)

    Pavel Studeny

    2013-01-01

    Full Text Available Purpose: To evaluate the outcomes of the hybrid technique of posterior lamellar keratoplasty (DMEK-S. Materials and Methods: 71 eyes of 55 patients enrolled in a single-center study underwent posterior lamellar keratoplasty with a hybrid lamella DMEK-S implanted using a solution implantation technique, owing to endothelial dysfunction. The outcome measures studied were visual acuity and endothelial cell density. Results: The rate of endothelial cell loss caused by surgery was 43.8%. During followups, we observed the stabilization of postoperative findings, or at minimum a very low rate of corneal endothelial cell loss. The UCDVA and BCDVA dramatically improved postoperatively. The rebubbling rate in our group of patients was 61.9%. We replaced the lamella due to its failure or malfunction in 17 patients (23.9%. Conclusion: In summary, DMEK-S combines the advantages of DSEK/DSAEK and DMEK. The central zone of bare Descemet’s membrane and endothelium allows for very good visual outcomes, and the peripheral rim allows for better manipulation of the lamella during implantation. It is an effective method of treating the endothelial dysfunction of various etiologies, but the high complication rate needs to be addressed before widespread implementation of the technique in the future.

  18. Regularized strings with extrinsic curvature

    International Nuclear Information System (INIS)

    Ambjoern, J.; Durhuus, B.

    1987-07-01

    We analyze models of discretized string theories, where the path integral over world sheet variables is regularized by summing over triangulated surfaces. The inclusion of curvature in the action is a necessity for the scaling of the string tension. We discuss the physical properties of models with extrinsic curvature terms in the action and show that the string tension vanishes at the critical point where the bare extrinsic curvature coupling tends to infinity. Similar results are derived for models with intrinsic curvature. (orig.)

  19. Conductivity of an inverse lyotropic lamellar phase under shear flow

    Science.gov (United States)

    Panizza, P.; Soubiran, L.; Coulon, C.; Roux, D.

    2001-08-01

    We report conductivity measurements on solutions of closed compact monodisperse multilamellar vesicles (the so-called ``onion texture'') formed by shearing an inverse lyotropic lamellar Lα phase. The conductivity measured in different directions as a function of the applied shear rate reveals a small anisotropy of the onion structure due to the existence of free oriented membranes. The results are analyzed in terms of a simple model that allows one to deduce the conductivity tensor of the Lα phase itself and the proportion of free oriented membranes. The variation of these two parameters is measured along a dilution line and discussed. The high value of the conductivity perpendicular to the layers with respect to that of solvent suggests the existence of a mechanism of ionic transport through the insulating solvent.

  20. Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

    International Nuclear Information System (INIS)

    Lavayen, V.; O'Dwyer, C.; Ana, M.A. Santa; Mirabal, N.; Benavente, E.; Cardenas, G.; Gonzalez, G.; Torres, C.M. Sotomayor

    2007-01-01

    This work explores the functionalization of an organic-inorganic MoS 2 lamellar compound, prepared by a chemical liquid deposition method (CLD), that has an interlamellar distance of ∼5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of ∼85 days, and a zeta potential measured to be ζ -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS 2 . SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS 2

  1. Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lavayen, V. [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland) and Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile)]. E-mail: vlavayen@tyndall.ie; O' Dwyer, C. [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland); Ana, M.A. Santa [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Mirabal, N. [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Benavente, E. [Department of Chemistry, Universidad Tecnologica Metropolitana, P.O. Box 9845, Santiago (Chile); Cardenas, G. [Department of Polymers, Faculty of Chemistry Science, Universidad de Concepcion, P.O. Box 160-C, Concepcion (Chile); Gonzalez, G. [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Torres, C.M. Sotomayor [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2007-01-30

    This work explores the functionalization of an organic-inorganic MoS{sub 2} lamellar compound, prepared by a chemical liquid deposition method (CLD), that has an interlamellar distance of {approx}5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of {approx}85 days, and a zeta potential measured to be {zeta} -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS{sub 2}. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS{sub 2}.

  2. Solvation thermodynamics of phenylalcohols in lamellar phase surfactant dispersions

    International Nuclear Information System (INIS)

    Martyniak, A.; Scheuermann, R.; Dilger, H.; Tucker, I.M.; Burkert, T.; Hashmi, A.S.K.; Vujosevic', D.; Roduner, E.

    2006-01-01

    The distribution and the stability of five phenylalcohols in a lamellar phase composed of simple bilayers separated by water at 298 and 348K is explored using avoided-level-crossing muon-spin resonance (ALC-μSR). The dependence of the alignment of the bilayer chains on temperature appears to be a crucial factor determining the phenylalcohol partitioning: increasing order of the surfactant tails leads to expulsion of the solute. Moreover, we observed a systematic trend, the longer the chain the deeper the phenyl group dips into the lipid bilayer. Recent studies have shown that the hydrophobic effect is adequate to describe membrane partitioning of small amphiphilic molecules. The solvation thermodynamic properties ΔG sol , ΔH sol , and ΔS sol which determine the solute transfer from the double layer into water prove that the distribution also strongly depends on shape, chemical nature and different structure of phenylalcohols

  3. Solvation thermodynamics of phenylalcohols in lamellar phase surfactant dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Martyniak, A. [Institut fuer Physikalische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Scheuermann, R. [Laboratory for muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Dilger, H. [Institut fuer Physikalische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Tucker, I.M. [Unilever Research and Development, Port Sunlight, Wirral CH63 3JW (United Kingdom); Burkert, T. [Institut fuer Organische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Hashmi, A.S.K. [Institut fuer Organische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Vujosevic' , D. [Institut fuer Physikalische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Roduner, E. [Institut fuer Physikalische Chemie, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)]. E-mail: e.roduner@ipc.uni-stuttgart.de

    2006-03-31

    The distribution and the stability of five phenylalcohols in a lamellar phase composed of simple bilayers separated by water at 298 and 348K is explored using avoided-level-crossing muon-spin resonance (ALC-{mu}SR). The dependence of the alignment of the bilayer chains on temperature appears to be a crucial factor determining the phenylalcohol partitioning: increasing order of the surfactant tails leads to expulsion of the solute. Moreover, we observed a systematic trend, the longer the chain the deeper the phenyl group dips into the lipid bilayer. Recent studies have shown that the hydrophobic effect is adequate to describe membrane partitioning of small amphiphilic molecules. The solvation thermodynamic properties {delta}G{sub sol}, {delta}H{sub sol}, and {delta}S{sub sol} which determine the solute transfer from the double layer into water prove that the distribution also strongly depends on shape, chemical nature and different structure of phenylalcohols.

  4. Structure-rheology relationship in a sheared lamellar fluid.

    Science.gov (United States)

    Jaju, S J; Kumaran, V

    2016-03-01

    The structure-rheology relationship in the shear alignment of a lamellar fluid is studied using a mesoscale model which provides access to the lamellar configurations and the rheology. Based on the equations and free energy functional, the complete set of dimensionless groups that characterize the system are the Reynolds number (ργL(2)/μ), the Schmidt number (μ/ρD), the Ericksen number (μγ/B), the interface sharpness parameter r, the ratio of the viscosities of the hydrophilic and hydrophobic parts μ(r), and the ratio of the system size and layer spacing (L/λ). Here, ρ and μ are the fluid density and average viscosity, γ is the applied strain rate, D is the coefficient of diffusion, B is the compression modulus, μ(r) is the maximum difference in the viscosity of the hydrophilic and hydrophobic parts divided by the average viscosity, and L is the system size in the cross-stream direction. The lattice Boltzmann method is used to solve the concentration and momentum equations for a two dimensional system of moderate size (L/λ=32) and for a low Reynolds number, and the other parameters are systematically varied to examine the qualitative features of the structure and viscosity evolution in different regimes. At low Schmidt numbers where mass diffusion is faster than momentum diffusion, there is fast local formation of randomly aligned domains with "grain boundaries," which are rotated by the shear flow to align along the extensional axis as time increases. This configuration offers a high resistance to flow, and the layers do not align in the flow direction even after 1000 strain units, resulting in a viscosity higher than that for an aligned lamellar phase. At high Schmidt numbers where momentum diffusion is fast, the shear flow disrupts layers before they are fully formed by diffusion, and alignment takes place by the breakage and reformation of layers by shear, resulting in defects (edge dislocations) embedded in a background of nearly aligned layers

  5. Distance-regular graphs

    NARCIS (Netherlands)

    van Dam, Edwin R.; Koolen, Jack H.; Tanaka, Hajime

    2016-01-01

    This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the monograph 'BCN'[Brouwer, A.E., Cohen, A.M., Neumaier,

  6. LL-regular grammars

    NARCIS (Netherlands)

    Nijholt, Antinus

    1980-01-01

    Culik II and Cogen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this paper we consider an analogous extension of the LL(k) grammars called the LL-regular grammars. The relation of this class of grammars to other classes of grammars will be shown. Any LL-regular

  7. Novel spatula and dissector for safer deep anterior lamellar keratoplasty

    Directory of Open Access Journals (Sweden)

    Gustavo ,2,3 Bonfadini

    2014-10-01

    Full Text Available Objective: We describe a novel spatula and dissector to facilitate the big-bubble technique in deep anterior lamellar keratoplasty (DALK. Methods: A 29-year-old man who was diagnosed with bilateral keratoconus underwent deep anterior lamellar keratoplasty (DALK. After 350μm partial thickness incision of the recipient cornea, the Bonfadini dissector was inserted at the deepest point in the peripheral incision and could be advanced to the center of the cornea safely because of its "semi-sharp" tip. After achieving the big-bubble (BB separation of Descemet membrane (DM from the overlying stroma, the anterior stromal disc was removed. Viscoelastic material was placed on the stromal bed to prevent uncontrolled collapse and perforation of DM during the paracentesis blade incision into the BB. We could detect the safe opening of the BB using the Bonfadini dissector by the leakage of air bubbles into the viscoelastic material. After injecting viscoelastic material into the BB space, we inserted the Bonfadini spatula into the bigbubble safely because of its curved profile and blunt edges. The groove along the length of the Bonfadini spatula enables safe and efficient incision or the residual stromal tissue using the pointed end of a sharp blade while protecting the underlying DM. After removal of posterior stroma, the donor button was sutured with 16 interrupted 10-0 nylon sutures. Results: This technique and the use of the Bonfadini spatula and dissector facilitate exposure of Descemet membrane. Conclusion: The smooth Bonfadini DALK spatula and dissector facilitate safe and efficient completion of DALK surgery.

  8. Regular Expression Pocket Reference

    CERN Document Server

    Stubblebine, Tony

    2007-01-01

    This handy little book offers programmers a complete overview of the syntax and semantics of regular expressions that are at the heart of every text-processing application. Ideal as a quick reference, Regular Expression Pocket Reference covers the regular expression APIs for Perl 5.8, Ruby (including some upcoming 1.9 features), Java, PHP, .NET and C#, Python, vi, JavaScript, and the PCRE regular expression libraries. This concise and easy-to-use reference puts a very powerful tool for manipulating text and data right at your fingertips. Composed of a mixture of symbols and text, regular exp

  9. Regularization by External Variables

    DEFF Research Database (Denmark)

    Bossolini, Elena; Edwards, R.; Glendinning, P. A.

    2016-01-01

    Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind of regula......Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind...

  10. Regular expressions cookbook

    CERN Document Server

    Goyvaerts, Jan

    2009-01-01

    This cookbook provides more than 100 recipes to help you crunch data and manipulate text with regular expressions. Every programmer can find uses for regular expressions, but their power doesn't come worry-free. Even seasoned users often suffer from poor performance, false positives, false negatives, or perplexing bugs. Regular Expressions Cookbook offers step-by-step instructions for some of the most common tasks involving this tool, with recipes for C#, Java, JavaScript, Perl, PHP, Python, Ruby, and VB.NET. With this book, you will: Understand the basics of regular expressions through a

  11. Surfactant assisted synthesis of lamellar nanostructured LiFePO4 at 388 K

    International Nuclear Information System (INIS)

    Liu Chao; Ma Dongxia; Ji Xiujie; Zhao Shanshan; Li Song

    2011-01-01

    Lamellar nanostructured lithium iron phosphate (Lα-LFP) was synthesized using anion surfactant sodium dodecyl sulphonate (SDS) as supermolecular template in water-ethanol media at 388 K under self-generated pressure. FeSO 4 , (NH 4 ) 2 HPO 4 and LiOH were used as Fe, P and Li sources, respectively. The inorganic phase was analyzed by X-ray diffraction (XRD). The morphology and the lamellar nanostructure were observed by field emitting scanning electron microscopy (FESEM). The results showed that the synthesized Lα-LFP presents not only the ordered lamellar microstructure accumulated by 20-40-nm thick LFP layers, but also the consequent self-assembled blocky particles of 0.5-1 μm. In contrast, template free LFP (TF-LFP) show a flake-shaped and mess-orientated microstructure. As a soft template, SDS played the roles of inducing the lamellar nanostructure, purifying the inorganic phase and decreasing the synthesis temperature.

  12. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, C. R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity.

  13. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    International Nuclear Information System (INIS)

    Spencer, C.R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity

  14. Microkeratome-assisted lamellar keratoplasty for keratoconus: stromal sandwich.

    Science.gov (United States)

    Bilgihan, Kamil; Ozdek, Sengül C; Sari, Ayça; Hasanreisoglu, Berati

    2003-07-01

    To evaluate microkeratome-assisted lamellar keratoplasty for the treatment of keratoconus when it is not possible to correct the astigmatic ametropia with contact lenses. Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey. This prospective study comprised 9 eyes of 7 keratoconus patients with contact lens intolerance. The donor cornea was prepared with a microkeratome and punched with a 7.25 mm or 7.50 mm trephine. Following the creation of a standard 9.0 mm corneal flap in the host cornea, the donor stromal button was implanted under this corneal flap like a sandwich. Transepithelial photorefractive keratectomy or laser in situ keratomileusis was performed when the corneal topography and refraction stabilized by the end of the sixth postoperative month. Follow-up ranged from 7 to 22 months. All patients gained 5 or more lines (mean 7.2 lines +/- 1.6 [SD]), and no patient lost a line of vision. The mean corneal thickness was 432.7 +/- 36.1 micrometers preoperatively and 578.1 +/- 45.1 micrometers after refractive surgery. The early visual results of this surgical technique are promising and seem to be comparable to those with penetrating keratoplasty.

  15. Butterfly patterns in a sheared lamellar-system

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, P [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Zipfel, J; Richtering, W [Freiburg Univ. (Germany)

    1997-04-01

    A technologically important extension of `classical` scattering techniques is to investigate soft-matter systems under non-equilibrium conditions. Shear flow is known to have a profound influence on the structure and orientation of complex fluids like thermotropic or lyotropic liquid-crystals, colloidal and polymeric solutions. There is a fundamental interest in understanding the microscopic structure and dynamics of such complex fluids as the macroscopic material properties might change with the application of an external perturbation like shear. The following example illustrates a recent study of the influence of shear on the structure of a lyotropic lamellar phase. Results using a cone-and-plate and the ILL Couette type shear-cell were obtained by rheo-small-angle light scattering (rheo-SALS) and small-angle neutron scattering (SANS) at D11. Because of the broad range of momentum transfer Q available at D11 a characteristic butterfly-pattern with a scattering peak revealing both the structure and the supramolecular structure of the system could be detected at very low Q. (author). 5 refs.

  16. A Two-Dimensional Lamellar Membrane: MXene Nanosheet Stacks.

    Science.gov (United States)

    Ding, Li; Wei, Yanying; Wang, Yanjie; Chen, Hongbin; Caro, Jürgen; Wang, Haihui

    2017-02-06

    Two-dimensional (2D) materials are promising candidates for advanced water purification membranes. A new kind of lamellar membrane is based on a stack of 2D MXene nanosheets. Starting from compact Ti 3 AlC 2 , delaminated nanosheets of the composition Ti 3 C 2 T x with the functional groups T (O, OH, and/or F) can be produced by etching and ultrasonication and stapled on a porous support by vacuum filtration. The MXene membrane supported on anodic aluminum oxide (AAO) substrate shows excellent water permeance (more than 1000 L m -2  h -1  bar -1 ) and favorable rejection rate (over 90 %) for molecules with sizes larger than 2.5 nm. The water permeance through the MXene membrane is much higher than that of the most membranes with similar rejections. Long-time operation also reveals the outstanding stability of the MXene membrane for water purification. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Lamellar ichthyosis maps to chromosome 14q11

    Energy Technology Data Exchange (ETDEWEB)

    Russell, L.J.; Compton, J.G.; Bale, S.J. [and others

    1994-09-01

    Lamellar ichthyosis (LI) is a serious skin disorder inherited as an autosomal recessive trait and characterized by large, brown plate-like scales covering the body. Skin involvement is apparent at birth, often as a collodion membrane. Scarring alopecia, ectropion, and secondary hypohidrosis are frequent. We used a panel of candidates genes that are expressed in the epidermis to study seven multiplex Caucasian families in the U.S. and six inbred (multiplex and simplex) families in Egypt. We find no recombination (Z=9.11 at {theta}=0) in either set of families with transglutaminse 1 (TGM1), the gene encoding the enzyme responsible for cross-linking proteins to the cell envelope in the upper-most layer of the epidermis. In addition, striking homozygosity is observed in the inbred families for markers neighboring TGM1, defining a 9.3 cM candidate region which is bounded by MYH7 and D14S275. This is the first report of linkage in LI and suggests that further study of the TGM1 gene may identify the underlying pathogenesis of this severe, disfiguring disorder. Linkage-based genetic counseling and prenatal diagnosis is now available for informative at-risk families.

  18. Micro alloyed steel weldability and sensibility testing on the lamellar cracks appearance

    Directory of Open Access Journals (Sweden)

    S. Stojadinović

    2011-07-01

    Full Text Available In this work are given the testing results of mechanical properties welded joints and microstructure of micro alloyed steel as well as its sensitivity to lamellar cracks appearance. The obtained results show that steel has good resistance to lamellar cracks appearance and with an appropriate wire choice for welding, a good combination of mechanical properties could be obtained at room (ambience temperatures as well as at low temperatures.

  19. Regularities of Multifractal Measures

    Indian Academy of Sciences (India)

    First, we prove the decomposition theorem for the regularities of multifractal Hausdorff measure and packing measure in R R d . This decomposition theorem enables us to split a set into regular and irregular parts, so that we can analyze each separately, and recombine them without affecting density properties. Next, we ...

  20. Stochastic analytic regularization

    International Nuclear Information System (INIS)

    Alfaro, J.

    1984-07-01

    Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)

  1. Thermal Conductivity of Superconductors in the Intermediate State: Size Effect in a Longitudinal Lamellar Structure

    International Nuclear Information System (INIS)

    Suter, J.M.; Rinderer, L.

    1978-01-01

    The thermal conductivity of type I superconductors has been measured in a well-defined, optically controlled intermediate-state configuration the so-called longitudinal lamellar structure (LLS). A regular arrangement of alternating normal and superconducting lamellas is obtained in an elongated plate by applying the magnetic field obliquely (following Sharvin) and decreasing it from the critical values. The heat current is set parallel to the lamellas. Due to the peculiar reflection law governing the quasiparticle reflections at a normal-superconductor interphase boundary, the thermal conductivity of the LLS is reduced when the electronic mean free path is larger than or comparable to the width of the lamellas. As first pointed out by Andreev, the reflection occurs with vecotr-momentum conservation, and only the quasiparticles moving nearly parallel to the lamellas can transport heat efficiently. The corresponding reduction of the thermal conductivity is a size effect.Systematic measurements of the thermal conductivity of the LLS in high-purity lead and tin are interpreted in terms of the size-effect model. The parameters of the model were experimentally determined in a preliminary study, to enable an unambiguous comparison with the theory. In particular, the geometrical aspects of the structures were studied using a magnetooptical technique. Interesting results on the characteristics of the LLS were obtained. The thermal conductivity data on lead essentially confirm the size-effect description. In tin heat transport by the lamellas of both types takes place, the heat carriers being the electrons (T > or approx. = 1.6 K). The discrepancy between the predictions of the size-effect model and the observed values in tin are attributed to an oversimplified calculation of the contribution of the superconducting lamellas to the conductivity

  2. Lamellar zirconium phosphates to host metals for catalytic purposes.

    Science.gov (United States)

    Ballesteros-Plata, Daniel; Infantes-Molina, Antonia; Rodríguez-Aguado, Elena; Braos-García, Pilar; Rodríguez-Castellón, Enrique

    2018-02-27

    In the present study a porous lamellar zirconium phosphate heterostructure (PPH) formed from zirconium(iv) phosphate expanded with silica galleries (P/Zr molar ratio equal to 2 and (Si + Zr)/P equal to 3) was prepared to host noble metals. Textural and structural characterization of PPH-noble metal materials was carried out in order to elucidate the location and dispersion of the metallic particles and the properties of the resulting material to be used in catalytic processes. In the present paper, their activity in the catalytic hydrodeoxygenation (HDO) reaction of dibenzofuran (DBF) was evaluated. X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) evidenced that the structure of the pillared zirconium phosphate material was not modified by the incorporation of Pt and Pd. Moreover, transmission electron microscopy (TEM) showed a different dispersion of the noble metal. The acidity of the resulting PPH-noble metal materials also changed, although in all cases the acidity was of weak nature, and the incorporation of noble metals affected Brønsted acid sites as observed from 31 P NMR spectra. In general, the textural, structural and acidic properties of the resulting materials suggest that PPH can be considered a good candidate to be used as a catalytic support. Thus, the catalytic results of the PPH-noble metal samples indicated that the Pd sample showed a stable behavior probably ascribed to a high dispersion of the active phase. However, the Pt sample suffered from fast deactivation. The selectivity to the reaction products was strongly dependent on the noble metal employed.

  3. Sparse structure regularized ranking

    KAUST Repository

    Wang, Jim Jing-Yan; Sun, Yijun; Gao, Xin

    2014-01-01

    Learning ranking scores is critical for the multimedia database retrieval problem. In this paper, we propose a novel ranking score learning algorithm by exploring the sparse structure and using it to regularize ranking scores. To explore the sparse

  4. Regular expression containment

    DEFF Research Database (Denmark)

    Henglein, Fritz; Nielsen, Lasse

    2011-01-01

    We present a new sound and complete axiomatization of regular expression containment. It consists of the conventional axiomatiza- tion of concatenation, alternation, empty set and (the singleton set containing) the empty string as an idempotent semiring, the fixed- point rule E* = 1 + E × E......* for Kleene-star, and a general coin- duction rule as the only additional rule. Our axiomatization gives rise to a natural computational inter- pretation of regular expressions as simple types that represent parse trees, and of containment proofs as coercions. This gives the axiom- atization a Curry......-Howard-style constructive interpretation: Con- tainment proofs do not only certify a language-theoretic contain- ment, but, under our computational interpretation, constructively transform a membership proof of a string in one regular expres- sion into a membership proof of the same string in another regular expression. We...

  5. Supersymmetric dimensional regularization

    International Nuclear Information System (INIS)

    Siegel, W.; Townsend, P.K.; van Nieuwenhuizen, P.

    1980-01-01

    There is a simple modification of dimension regularization which preserves supersymmetry: dimensional reduction to real D < 4, followed by analytic continuation to complex D. In terms of component fields, this means fixing the ranges of all indices on the fields (and therefore the numbers of Fermi and Bose components). For superfields, it means continuing in the dimensionality of x-space while fixing the dimensionality of theta-space. This regularization procedure allows the simple manipulation of spinor derivatives in supergraph calculations. The resulting rules are: (1) First do all algebra exactly as in D = 4; (2) Then do the momentum integrals as in ordinary dimensional regularization. This regularization procedure needs extra rules before one can say that it is consistent. Such extra rules needed for superconformal anomalies are discussed. Problems associated with renormalizability and higher order loops are also discussed

  6. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  7. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  8. En face spectral domain optical coherence tomography analysis of lamellar macular holes.

    Science.gov (United States)

    Clamp, Michael F; Wilkes, Geoff; Leis, Laura S; McDonald, H Richard; Johnson, Robert N; Jumper, J Michael; Fu, Arthur D; Cunningham, Emmett T; Stewart, Paul J; Haug, Sara J; Lujan, Brandon J

    2014-07-01

    To analyze the anatomical characteristics of lamellar macular holes using cross-sectional and en face spectral domain optical coherence tomography. Forty-two lamellar macular holes were retrospectively identified for analysis. The location, cross-sectional length, and area of lamellar holes were measured using B-scans and en face imaging. The presence of photoreceptor inner segment/outer segment disruption and the presence or absence of epiretinal membrane formation were recorded. Forty-two lamellar macular holes were identified. Intraretinal splitting occurred within the outer plexiform layer in 97.6% of eyes. The area of intraretinal splitting in lamellar holes did not correlate with visual acuity. Eyes with inner segment/outer segment disruption had significantly worse mean logMAR visual acuity (0.363 ± 0.169; Snellen = 20/46) than in eyes without inner segment/outer segment disruption (0.203 ± 0.124; Snellen = 20/32) (analysis of variance, P = 0.004). Epiretinal membrane was present in 34 of 42 eyes (81.0%). En face imaging allowed for consistent detection and quantification of intraretinal splitting within the outer plexiform layer in patients with lamellar macular holes, supporting the notion that an area of anatomical weakness exists within Henle's fiber layer, presumably at the synaptic connection of these fibers within the outer plexiform layer. However, the en face area of intraretinal splitting did not correlate with visual acuity, disruption of the inner segment/outer segment junction was associated with significantly worse visual acuity in patients with lamellar macular holes.

  9. Vacuolar ATPase regulates surfactant secretion in rat alveolar type II cells by modulating lamellar body calcium.

    Directory of Open Access Journals (Sweden)

    Narendranath Reddy Chintagari

    2010-02-01

    Full Text Available Lung surfactant reduces surface tension and maintains the stability of alveoli. How surfactant is released from alveolar epithelial type II cells is not fully understood. Vacuolar ATPase (V-ATPase is the enzyme responsible for pumping H(+ into lamellar bodies and is required for the processing of surfactant proteins and the packaging of surfactant lipids. However, its role in lung surfactant secretion is unknown. Proteomic analysis revealed that vacuolar ATPase (V-ATPase dominated the alveolar type II cell lipid raft proteome. Western blotting confirmed the association of V-ATPase a1 and B1/2 subunits with lipid rafts and their enrichment in lamellar bodies. The dissipation of lamellar body pH gradient by Bafilomycin A1 (Baf A1, an inhibitor of V-ATPase, increased surfactant secretion. Baf A1-stimulated secretion was blocked by the intracellular Ca(2+ chelator, BAPTA-AM, the protein kinase C (PKC inhibitor, staurosporine, and the Ca(2+/calmodulin-dependent protein kinase II (CaMKII, KN-62. Baf A1 induced Ca(2+ release from isolated lamellar bodies. Thapsigargin reduced the Baf A1-induced secretion, indicating cross-talk between lamellar body and endoplasmic reticulum Ca(2+ pools. Stimulation of type II cells with surfactant secretagogues dissipated the pH gradient across lamellar bodies and disassembled the V-ATPase complex, indicating the physiological relevance of the V-ATPase-mediated surfactant secretion. Finally, silencing of V-ATPase a1 and B2 subunits decreased stimulated surfactant secretion, indicating that these subunits were crucial for surfactant secretion. We conclude that V-ATPase regulates surfactant secretion via an increased Ca(2+ mobilization from lamellar bodies and endoplasmic reticulum, and the activation of PKC and CaMKII. Our finding revealed a previously unrealized role of V-ATPase in surfactant secretion.

  10. Incidental Finding of Lamellar Calcification of the Falx Cerebri Leading to the Diagnosis of Gorlin-Goltz Syndrome

    Directory of Open Access Journals (Sweden)

    I. Saulite

    2013-10-01

    Full Text Available Here, we report the case of an incidental finding of lamellar calcification of the falx cerebri in a routine computed tomography scan of the head after an accidental trauma. This lamellar calcification led to the diagnosis of Gorlin-Goltz syndrome (GGS in the patient and her daughter. Lamellar calcification of the falx cerebri is a pathognomonic feature of GGS. Our case report highlights the importance of a multidisciplinary diagnostic approach to GGS.

  11. Incidental finding of lamellar calcification of the falx cerebri leading to the diagnosis of gorlin-goltz syndrome.

    Science.gov (United States)

    Saulite, I; Voykov, B; Mehra, T; Hoetzenecker, W; Guenova, E

    2013-01-01

    Here, we report the case of an incidental finding of lamellar calcification of the falx cerebri in a routine computed tomography scan of the head after an accidental trauma. This lamellar calcification led to the diagnosis of Gorlin-Goltz syndrome (GGS) in the patient and her daughter. Lamellar calcification of the falx cerebri is a pathognomonic feature of GGS. Our case report highlights the importance of a multidisciplinary diagnostic approach to GGS.

  12. Direct Visualisation of the Structural Transformation between the Lyotropic Liquid Crystalline Lamellar and Bicontinuous Cubic Mesophase.

    Science.gov (United States)

    Tran, Nhiem; Zhai, Jiali; Conn, Charlotte E; Mulet, Xavier; Waddington, Lynne J; Drummond, Calum J

    2018-05-29

    The transition between the lyotropic liquid crystalline lamellar and the bicontinuous cubic mesophase drives multiple fundamental cellular processes involving changes in cell membrane topology including endocytosis and membrane budding. While several theoretical models have been proposed to explain this dynamic transformation, experimental validation of these models has been challenging due to the short lived nature of the intermediates present during the phase transition. Herein, we report the direct observation of a lamellar to bicontinuous cubic phase transition in nanoscale dispersions using a combination of cryogenic transmission electron microscopy and static small angle X-ray scattering. The results represent the first experimental confirmation of a theoretical model which proposed that the bicontinuous cubic phase originates from the centre of a lamellar vesicle, then propagates outward via the formation of inter-lamellar attachments and stalks. The observation was possible due to the precise control of the lipid composition to place the dispersion systems at the phase boundary of a lamellar and a cubic phase, allowing for the creation of long-lived structural intermediates. By surveying the nanoparticles using cryogenic transmission electron microscopy, a complete phase transition sequence was established.

  13. Remote manipulation of posterior lamellar corneal grafts using a magnetic field.

    Science.gov (United States)

    Nahum, Yoav; Barliya, Tilda; Bahar, Irit; Livnat, Tami; Nisgav, Yael; Weinberger, Dov

    2013-06-01

    In posterior lamellar keratoplasty procedures such as Descemet stripping endothelial keratoplasty and Descemet membrane endothelial keratoplasty, the lamellar graft is manipulated directly or by injecting an air bubble. This preliminary study sought to evaluate the feasibility of guiding lamellar corneal grafts by generating a magnetic field. Rabbit and porcine Descemet stripping endothelial keratoplasty and Descemet membrane endothelial keratoplasty grafts were manually produced and immersed in a ferromagnetic solution containing nanomagnetic particles conjugated to streptavidin or in gadoteric acid. For the feasibility study, grafts were transferred to an artificial anterior chamber or plastic test tube and a magnetic field was generated with a handheld NdFeB disc magnet. The presence and the sustainability of graft motion were documented under various conditions. For the semiquantitative study, whole or partial grafts were transferred to a plastic test tube after immersion, and the amount of tissue retraction induced by the remote magnet was graded. The grafts were successfully manipulated in all directions by the magnet, from a distance of up to 7 mm. They remained ferromagnetic more than 24 hours after immersion in the ferromagnetic solutions. The degree of retraction was affected by graft size, immersion time, time from immersion, and immersion solution. Posterior lamellar corneal grafts may be made ferromagnetic and remotely manipulated by creation of a magnetic field. The ferromagnetic properties are adjustable. This technique holds promise in attaching and repositioning grafts during keratoplasty. Further research is needed to assess the possible effects of ferromagnetic solutions on corneal endothelial cells and on lamellar graft clarity.

  14. Electrochemical properties and diffusion of a redox active surfactant incorporated in bicontinuous cubic and lamellar phase

    International Nuclear Information System (INIS)

    Kostela, J.; Elmgren, M.; Almgren, M.

    2005-01-01

    The objective of this study was to investigate the electrochemical behaviour of the divalent redox active surfactant, N-cetyl-N'-methylviologen (CMV), in bicontinuous cubic and lamellar phases. The liquid crystalline phases were prepared from the system glycerolmonooleate (GMO)-water (and brine)-cationic surfactant. A comparison of the phase behaviour of GMO with the monovalent cetyltrimethylammonium bromide (CTAB) and the divalent CMV surfactant showed that the surfactants gave about the same effect at the same surface charge density. The electrochemical measurements were made with a mixture of CTAB and CMV as the surfactant. Cyclic voltammetry was used to study the electrochemistry of CMV incorporated in the cubic and lamellar phases that were spread on a gold electrode. The E 0 -values in the cubic samples were more negative (-0.55 V versus SCE) than in the lamellar samples (-0.53 V versus SCE). This can be explained by the higher charge density in the lamellar phase. The diffusion coefficients were also measured in the cubic phase. The mass transport is slowed down about fifty times in the cubic phase compared to in the pure electrolyte. The concentration dependence on the diffusion coefficient was also investigated. No electron hopping could be observed, which suggest that diffusional movement of the redox probe is the main source of charge transport. By placing the samples on a conducting glass slide, spectroelectrochemical investigations were performed. In the lamellar phase strong dimerization was detected at high concentration of viologen, but much less in the cubic phase

  15. Manifold Regularized Reinforcement Learning.

    Science.gov (United States)

    Li, Hongliang; Liu, Derong; Wang, Ding

    2018-04-01

    This paper introduces a novel manifold regularized reinforcement learning scheme for continuous Markov decision processes. Smooth feature representations for value function approximation can be automatically learned using the unsupervised manifold regularization method. The learned features are data-driven, and can be adapted to the geometry of the state space. Furthermore, the scheme provides a direct basis representation extension for novel samples during policy learning and control. The performance of the proposed scheme is evaluated on two benchmark control tasks, i.e., the inverted pendulum and the energy storage problem. Simulation results illustrate the concepts of the proposed scheme and show that it can obtain excellent performance.

  16. In-Situ TEM Study of Interface Sliding and Migration in an Ultrafine Lamellar Structure

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L M

    2005-12-06

    The instability of interfaces in an ultrafine TiAl-({gamma})/Ti{sub 3}Al-({alpha}{sub 2}) lamellar structure by straining at room temperature has been investigated using in-situ straining techniques performed in a transmission electron microscope. The purpose of this study is to obtain experimental evidence to support the creep mechanisms based upon the interface sliding in association with a cooperative movement of interfacial dislocations previously proposed to interpret the nearly linear creep behavior observed from ultrafine lamellar TiAl alloys. The results have revealed that both the sliding and migration of lamellar interfaces can take place simultaneously as a result of the cooperative movement of interfacial dislocations.

  17. Development of lamellar structures in natural waxes - an electron diffraction investigation

    Energy Technology Data Exchange (ETDEWEB)

    Dorset, Douglas L. [Electron Diffraction Department, Hauptman-Woodward Medical Research Institute, Inc., Buffalo, NY (United States)

    1999-06-07

    When they are recrystallized from the melt, natural plant or insect waxes tend to form solid phases with a nematic-like structure (i.e. a parallel array of polymethylene chains with little or no aggregation of the molecules into distinct layers). An electron diffraction study of carnauba wax and two types of beeswax has shown that the degree of molecular organization into lamellar structures can be enhanced by annealing in the presence of benzoic acid, which also acts as an epitaxial substrate. Nevertheless, the resultant layer structure in the annealed solid is not the same as that found for paraffin wax fractions refined from petroleum. Probably because of a small but significant fraction of a very long chain ingredient, the lamellar separation is incomplete, incorporating a number of 'bridging molecules' that span the nascent lamellar interface.The same phenomenon has been described recently for a low molecular weight polyethylene. (author)

  18. Development of lamellar structures in natural waxes - an electron diffraction investigation

    Science.gov (United States)

    Dorset, Douglas L.

    1999-06-01

    When they are recrystallized from the melt, natural plant or insect waxes tend to form solid phases with a nematic-like structure (i.e. a parallel array of polymethylene chains with little or no aggregation of the molecules into distinct layers). An electron diffraction study of carnauba wax and two types of beeswax has shown that the degree of molecular organization into lamellar structures can be enhanced by annealing in the presence of benzoic acid, which also acts as an epitaxial substrate. Nevertheless, the resultant layer structure in the annealed solid is not the same as that found for paraffin wax fractions refined from petroleum. Probably because of a small but significant fraction of a very long chain ingredient, the lamellar separation is incomplete, incorporating a number of `bridging molecules' that span the nascent lamellar interface.The same phenomenon has been described recently for a low molecular weight polyethylene.

  19. How do closed-compact multi-lamellar droplets form under shear flow? A possible mechanism

    Science.gov (United States)

    Courbin, L.; Pons, R.; Rouch, J.; Panizza, P.

    2003-01-01

    The formation of closed-compact multi-lamellar droplets obtained upon shearing both a lamellar phase (Lα) and a two-phase separated lamellar-sponge (Lα-L3) mixture is investigated as a function of the shear rate dot gamma, using small-angle light scattering (SALS) and cross-polarized optical microscopy. In both systems the formation of droplets occurs homogeneously in the cell at a well-defined wave vector qe propto dot gamma1/3 via a strain-controlled process. These results suggest that the formation of droplets may be monitored in both systems by a buckling instability of the lamellae as predicted from a recent theory.

  20. One- and two-dimensional fluids properties of smectic, lamellar and columnar liquid crystals

    CERN Document Server

    Jakli, Antal

    2006-01-01

    Smectic and lamellar liquid crystals are three-dimensional layered structures in which each layer behaves as a two-dimensional fluid. Because of their reduced dimensionality they have unique physical properties and challenging theoretical descriptions, and are the subject of much current research. One- and Two-Dimensional Fluids: Properties of Smectic, Lamellar and Columnar Liquid Crystals offers a comprehensive review of these phases and their applications. The book details the basic structures and properties of one- and two-dimensional fluids and the nature of phase transitions. The later chapters consider the optical, magnetic, and electrical properties of special structures, including uniformly and non-uniformly aligned anisotropic films, lyotropic lamellar systems, helical and chiral structures, and organic anisotropic materials. Topics also include typical and defective features, magnetic susceptibility, and electrical conductivity. The book concludes with a review of current and potential applications ...

  1. Strengthening behavior of beta phase in lamellar microstructure of TiAl alloys

    Science.gov (United States)

    Zhu, Hanliang; Seo, D. Y.; Maruyama, K.

    2010-01-01

    β phase can be introduced to TiAl alloys by the additions of β stabilizing elements such as Cr, Nb, W, and Mo. The β phase has a body-centered cubic lattice structure and is softer than the α2 and γ phases in TiAl alloys at elevated temperatures, and hence is thought to have a detrimental effect on creep strength. However, fine β precipitates can be formed at lamellar interfaces by proper heat treatment conditions and the β interfacial precipitate improves the creep resistance of fully lamellar TiAl alloys, since the phase interface of γ/β retards the motion of dislocations during creep. This paper reviews recent research on high-temperature strengthening behavior of the β phase in fully lamellar TiAl alloys.

  2. Morphological abnormalities and apoptosis in lamellar tissue of equines after intestinal obstruction and treatment with hydrocortisone

    Directory of Open Access Journals (Sweden)

    L.M Laskoski

    2010-12-01

    Full Text Available Four experimental groups of equines were used in order to study morphological abnormalities and apoptosis in lamellar tissue. Group Cg (control was composed of animals without any surgical procedure; group Ig (instrumented, animals that underwent enterotomy; group Tg (treated, animals that were subjected to intestinal obstruction and were treated with hydrocortisone; and group Ug (untreated, animals that were subjected to intestinal obstruction without treatment. The lamellar tissue was analyzed regarding the presence of tissue abnormalities and apoptosis. No morphological abnormalities were observed in animals of surgical groups, and no difference in apoptosis was observed between groups. It was concluded that intestinal obstruction allowed laminitis to develop, probably by systemic activation, and that the maneuvers performed in the enterotomy aggravated the process. Hydrocortisone did not aggravate the lesions of the lamellar tissue

  3. Quantitative analysis of lamellar bodies in amniotic fluid as fetal pulmonary maturity indicator

    Directory of Open Access Journals (Sweden)

    Ljubić Vesna

    2009-01-01

    Full Text Available Background/Aim. Although lamellar bodies have been the center of interest over the last years, the published results of fetal pulmonary maturity determination according to their concentration in amniotic fluid are controversial. The aim of this study was to determine the significance of lamellar bodies, as well as the ratio lecithin/sphingomyelin (L/S in amniotic fluid for the assessment of fetal pulmonary maturity. Methods. This prospective 2-year study included 102 female examinees, ranging from 17 to 44 years of age, in whom lamellar bodies concentrations in amniotic fluid were determined to check the efficacy of the applied therapy for obtaining arteficial fetal pulmonary maturity. The shake test was applied as a comparative test for determining a quantitative L/S ratio. To determine a fetus maturity and development stage we followed up biparietal diameter, abdominal circumference, femure length, ponderal index at birth and body mass. Results. Out of a total of 102 amniocenteses within a period from 26th to 40th gestation week only 70 results were considered due to 32 unknown neonatal outcomes. Biparietal diameter was 224-362 mm, femur length 56 - 78 mm, ponderal index 1.22-2.84, fetus body mass 1300- 4 350 g. There was found a significant relation between gestation age and lamellar bodies concentration (R = 0.396398, p < 0.01, as well as between gestation age and the ratio L/S (R = 0.691297, p < 0.01. Also, there was a significant correlation of lamellar bodies concentration to the ratio L/S determined (R = 0.493609, p < 0.01. Conclusion. Determination of lamellar bodies concentration values is a reliable method to confirm fetal pulmonary maturity.

  4. Lamellar Diblock Copolymer Thin Films during Solvent Vapor Annealing Studied by GISAXS

    DEFF Research Database (Denmark)

    Zhang, Jianqi; Posselt, Dorthe; Smilgies, Detlef-M.

    2014-01-01

    The reorientation of lamellae and the dependence of the lamellar spacing, Dlam, on polymer volume fraction, ϕP, Dlam ∝ ϕP–β, in diblock copolymer thin films during solvent vapor annealing (SVA) are examined by combining white light interferometry (WLI) and grazing-incidence small-angle X-ray scat......The reorientation of lamellae and the dependence of the lamellar spacing, Dlam, on polymer volume fraction, ϕP, Dlam ∝ ϕP–β, in diblock copolymer thin films during solvent vapor annealing (SVA) are examined by combining white light interferometry (WLI) and grazing-incidence small-angle X...

  5. Preparation and characterisation of polymeric lamellar substrate particles (PLSP)

    International Nuclear Information System (INIS)

    Khairullah, Noor Hasnah Mohamed

    2002-01-01

    Polymer microparticles have tremendous potential as the next generation of adjuvant systems to replace the only adjuvant currently widely registered for human use, alum. Based on aluminium salts, alum adjuvants work as short-term depots of adsorbed protein/antigens that slowly 'leak' into the body's immune system, inducing immunity by invoking a humoral response. The main disadvantage of alum adjuvants is that they do not raise sufficient antibody levels to induce long-term immunity. Hence, booster administrations are required. This drawback presents the biggest factor in the failure of many vaccination programmes. Polymer microparticulate systems can be fashioned to deliver sub-unit and peptide antigens in a continuous or controlled rate over a desired period of time, avoiding the need for booster doses. The design of mucosal vaccines is now centred upon the use of these polymeric carriers. The mucosal route for immunisation has many advantages over the more conventional systemic route, the most important of which, is the induction of both humoral and cellular immunity. Polymer microspheres of sizes <10μm are especially good candidates as oral vaccine adjuvants as they are taken up by the M cells of the Peyer's patches in the intestine. Numerous studies have been carried out on microspheres into which antigens have been encapsulated or entrapped. There are, however, problems associated with loss of antigenicity since formulation procedures involve the use of organic solvents and harsh shearing methods. Additionally, these antigens may be further degraded when the polymer material itself degrades in vivo and produces acidic species. A novel adjuvant system that avoids the above problems is currently being evaluated. Poly(l-lactide) (PLLA) polymeric lamellar substrate particles (PLSP) are promising as novel adjuvants for the controlled release of antigens. Reports have shown that the adsorption of antigens onto the surface of these particles can induce cellular

  6. Mechanical behavior and related microstructural aspects of a nano-lamellar TiAl alloy at elevated temperatures

    International Nuclear Information System (INIS)

    Klein, T.; Usategui, L.; Rashkova, B.; Nó, M.L.; San Juan, J.; Clemens, H.; Mayer, S.

    2017-01-01

    Advanced intermetallic γ-TiAl based alloys, which solidify via the disordered β phase, such as the TNM"+ alloy, are considered as most promising candidates for structural applications at high temperatures in aero and automotive industries, where they are applied increasingly. Particularly creep resistant microstructures required for high-temperature application, i.e. fine fully lamellar microstructures, can be attained via two-step heat-treatments. Thereby, an increasing creep resistance is observed with decreasing lamellar interface spacing. Once lamellar structures reach nano-scaled dimensions, deformation mechanisms are altered dramatically. Hence, this study deals with a detailed characterization of the elevated temperature deformation phenomena prevailing in nano-lamellar TiAl alloys by the use of tensile creep experiments and mechanical spectroscopy. Upon creep exposure, microstructural changes occur in the lamellar structure, which are analyzed by the comparative utilization of X-ray diffraction, scanning and transmission electron microscopy as well as atom probe tomography. Creep activation parameters determined by mechanical characterization suggest the dominance of dislocation climb by a jog-pair formation process. The dislocations involved in deformation are, in nano-lamellar TiAl alloys, situated at the lamellar interfaces. During creep exposure the precipitation of β_o phase and ζ-silicide particles is observed emanating from the α_2 phase, which is due to the accumulation of Mo and Si at lamellar interfaces.

  7. Diverse Regular Employees and Non-regular Employment (Japanese)

    OpenAIRE

    MORISHIMA Motohiro

    2011-01-01

    Currently there are high expectations for the introduction of policies related to diverse regular employees. These policies are a response to the problem of disparities between regular and non-regular employees (part-time, temporary, contract and other non-regular employees) and will make it more likely that workers can balance work and their private lives while companies benefit from the advantages of regular employment. In this paper, I look at two issues that underlie this discussion. The ...

  8. Sparse structure regularized ranking

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-04-17

    Learning ranking scores is critical for the multimedia database retrieval problem. In this paper, we propose a novel ranking score learning algorithm by exploring the sparse structure and using it to regularize ranking scores. To explore the sparse structure, we assume that each multimedia object could be represented as a sparse linear combination of all other objects, and combination coefficients are regarded as a similarity measure between objects and used to regularize their ranking scores. Moreover, we propose to learn the sparse combination coefficients and the ranking scores simultaneously. A unified objective function is constructed with regard to both the combination coefficients and the ranking scores, and is optimized by an iterative algorithm. Experiments on two multimedia database retrieval data sets demonstrate the significant improvements of the propose algorithm over state-of-the-art ranking score learning algorithms.

  9. 'Regular' and 'emergency' repair

    International Nuclear Information System (INIS)

    Luchnik, N.V.

    1975-01-01

    Experiments on the combined action of radiation and a DNA inhibitor using Crepis roots and on split-dose irradiation of human lymphocytes lead to the conclusion that there are two types of repair. The 'regular' repair takes place twice in each mitotic cycle and ensures the maintenance of genetic stability. The 'emergency' repair is induced at all stages of the mitotic cycle by high levels of injury. (author)

  10. Regularization of divergent integrals

    OpenAIRE

    Felder, Giovanni; Kazhdan, David

    2016-01-01

    We study the Hadamard finite part of divergent integrals of differential forms with singularities on submanifolds. We give formulae for the dependence of the finite part on the choice of regularization and express them in terms of a suitable local residue map. The cases where the submanifold is a complex hypersurface in a complex manifold and where it is a boundary component of a manifold with boundary, arising in string perturbation theory, are treated in more detail.

  11. Regularizing portfolio optimization

    International Nuclear Information System (INIS)

    Still, Susanne; Kondor, Imre

    2010-01-01

    The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

  12. Regularizing portfolio optimization

    Science.gov (United States)

    Still, Susanne; Kondor, Imre

    2010-07-01

    The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

  13. Regular Single Valued Neutrosophic Hypergraphs

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Malik

    2016-12-01

    Full Text Available In this paper, we define the regular and totally regular single valued neutrosophic hypergraphs, and discuss the order and size along with properties of regular and totally regular single valued neutrosophic hypergraphs. We also extend work on completeness of single valued neutrosophic hypergraphs.

  14. The geometry of continuum regularization

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1987-03-01

    This lecture is primarily an introduction to coordinate-invariant regularization, a recent advance in the continuum regularization program. In this context, the program is seen as fundamentally geometric, with all regularization contained in regularized DeWitt superstructures on field deformations

  15. Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser

    DEFF Research Database (Denmark)

    Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders Højslet

    2012-01-01

    (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Conclusions: Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months...

  16. Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk

    NARCIS (Netherlands)

    Matsushita, Y; Iwata, H; Asari, T; Uchida, T; ten Brinke, G; Takano, A

    2004-01-01

    Chain elongation suppression of cyclic block copolymers in microphase-separated bulk was determined quantitatively. Solvent-cast and annealed films are confirmed to show alternating lamellar structure and their microdomain spacing D increases with increasing total molecular weight M according to the

  17. Early surfactant guided by lamellar body counts on gastric aspirate in very preterm infants

    DEFF Research Database (Denmark)

    Verder, Henrik Axel; Ebbesen, Finn Oluf; Fenger-Grøn, Jesper

    2013-01-01

    We have developed a rapid method, based on lamellar body counts (LBC) on gastric aspirate, for identifying newborns who will develop respiratory distress syndrome with a need for surfactant supplementation. Objective: We set out to test whether it was possible to improve the outcome when used in ...

  18. Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

    Czech Academy of Sciences Publication Activity Database

    Balcar, Hynek; Žilková, Naděžda; Kubů, Martin; Mazur, Michal; Bastl, Zdeněk; Čejka, Jiří

    2015-01-01

    Roč. 11, NOV 2015 (2015), s. 2087-2096 ISSN 1860-5397 Institutional support: RVO:61388955 Keywords : Hoveyda-Grubbs type catalyst * hybrid catalysts * lamellar zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.697, year: 2015

  19. The lamellar period in symmetric diblock copolymer thin films studied by neutron reflectivity and AFM

    DEFF Research Database (Denmark)

    Gadegaard, N.; Almdal, K.; Larsen, N.B.

    1999-01-01

    The lamellar structure of a symmetric diblock copolymer was studied as a function of temperature. We used dPEP-PDMS with a molecular weight of 8.3 kg/mol as model system. The polymer was dissolved in chloroform and spin-casted on silicon wafers into thin uniform films. The degree and direction...

  20. Minimal compliance design for metal–ceramic composites with lamellar microstructures

    DEFF Research Database (Denmark)

    Piat, R.; Sinchuk, Y.; Vasoya, M.

    2011-01-01

    of lamellar domains. With local ceramic volume fraction and lamella orientation chosen as the design variables, a minimum compliance optimization problem is solved based on topology optimization and finite element methods for metal–ceramic samples with different geometries and boundary conditions...

  1. Effect of the Molecular Weight of AB Diblock Copolymers on the Lamellar Orientation in Thin Films

    DEFF Research Database (Denmark)

    Potemkin, Igor I.; Busch, Peter; Smilgies, Detlef-M

    2007-01-01

    We propose a theoretical explanation of the parallel and perpendicular lamellar orientations in free surface films of symmetric polystyrene-block-polybutadiene diblock copolymers on silicon substrates (with a native SiOx layer). Two approaches are developed: A correction to the strong segregation...

  2. Shear-induced morphology transition and microphase separation in a lamellar phase doped with clay particles.

    Science.gov (United States)

    Nettesheim, Florian; Grillo, Isabelle; Lindner, Peter; Richtering, Walter

    2004-05-11

    We report on the influence of shear on a nonionic lamellar phase of tetraethyleneglycol monododecyl ether (C12E4) in D2O containing clay particles (Laponite RD). The system was studied by means of small-angle light scattering (SALS) and small-angle neutron scattering (SANS) under shear. The SANS experiments were conducted using a H2O/D2O mixture of the respective scattering length density to selectively match the clay scattering. The rheological properties show the familiar shear thickening regime associated with the formation of multilamellar vesicles (MLVs) and a shear thinning regime at higher stresses. The variation of viscosity is less pronounced as commonly observed. In the shear thinning regime, depolarized SALS reveals an unexpectedly strong variation of the MLV size. SANS experiments using the samples with lamellar contrast reveal a change in interlamellar spacing of up to 30% at stresses that lead to MLV formation. This change is much more pronounced than the change observed, when shear suppresses thermal bilayer undulations. Microphase separation occurs, and as a consequence, the lamellar spacing decreases drastically. The coincidence of the change in lamellar spacing and the onset of MLV formation is a strong indication for a morphology-driven microphase separation.

  3. Multiscale Simulations of Lamellar PS–PEO Block Copolymers Doped with LiPF6 Ions

    KAUST Repository

    Sethuraman, Vaidyanathan; Mogurampelly, Santosh; Ganesan, Venkat

    2017-01-01

    We report the results of atomistic simulations of the structural equilibrium properties of PS–PEO block copolymer (BCP) melt in the ordered lamellar phase doped with LiPF6 salt. A hybrid simulation strategy, consisting of steps of coarse

  4. Incorporation of poly-saccharidic derivatives in model biological systems: monolayers, lamellar phases and vesicles

    International Nuclear Information System (INIS)

    Deme, Bruno

    1995-01-01

    Our aim is to introduce a soluble polymer in a lyotropic lamellar phase, and to modify the force balance in the case of a collapsed system where no repulsive contribution overcomes the van der Waals attraction, except at very short distances where hydration forces dominate (i.e. a collapsed stack of membranes). Mixed layers of a synthetic lecithin (DMPC) and a hydrophobically modified polysaccharide (cholesteryl-pullulan, CHP) have been investigated at the air-water interface by surface tension experiments and by specular reflection of neutrons. The DMPC/CHP/water ternary phase diagram has been determined by small angle X-ray scattering (SAXS) and small angle neutron scattering (SANS). CHP derivatives are associative polymers bearing lateral cholesterol groups that interact with a polar phases such as phospholipid monolayers and biological membranes. These derivatives are surface active and self-aggregate in solution leading to the formation of soluble micellar type aggregates. The interaction of CHP derivatives with lipidic structures involves the anchoring of the cholesterol groups that yields to the tethering of the poly-saccharidic backbones at lipid/water interfaces. These poly-saccharidic backbones are flexible chains in good solvent in water. Using these derivatives and a new preparation procedure, we show that it is possible to avoid the depletion of the polysaccharide due to its steric exclusion by the collapsed DMPC lamellar phase. We are able to prepare samples at thermodynamic equilibrium with the polysaccharide solubilized in the lamellar phase, a situation opposed to the well known behavior of mixed polysaccharide/lecithin Systems commonly used in osmotic stress experiments. Here, the osmotic pressure of the chains confined in the lamellar lattice acts as a new long range repulsive contribution in the DMPC lyotropic L_α phase and results in the swelling of the lamellar phase at large membrane separations (570 A). Such bilayer separations allow out of

  5. Chain confinement, phase transitions, and lamellar structure in semicrystalline polymers, polymer blends and polymer nanocomposites

    Science.gov (United States)

    Chen, Huipeng

    Recent studies suggest that there are three phase fractions in semicrystalline polymers, the crystalline, the mobile amorphous and the rigid amorphous phases. Due to the distinct properties of the rigid amorphous fraction, RAF, it has been investigated for more than twenty years. In this thesis, a general method using quasi-isothermal temperature-modulated differential scaning calorimetry, DSC, is provided for the first time to obtain the temperature dependent RAF and the other two fractions, crystalline fraction and mobile amorphous fraction, MAF. For poly(ethylene terephthalate), PET, our results show RAF was vitrified during quasi-isothermal cooling after crystallization had been completed and became totally devitrified during quasi-isothermal heating before the start of melting. Several years after people initially discovered the existence of RAF, another issue arose relating to the physical location of RAF and mobile amorphous fraction, MAF, within a lamellar stack model. Two very different models to describe the location of RAF were proposed. In the Heterogeneous Stack Model, HET, RAF is located outside the lamellar stacks. In the Homogeneous Stack Model, HSM, RAF was located inside the lamellar stacks. To determine the lamellar structure of semicrystalline polymers comprising three phase, a general method is given in this thesis by using a combination of the DSC and small angle X-ray scattering, SAXS techniques. It has been applied to Nylon 6, isotactic polystyrene, iPS, and PET. It was found for all of these materials, the HSM model is correct to describe the lamellar structure. In addition to the determination of lamellar structures, this method can also provide the exact fraction of MAF inside and outside lamellar stacks for binary polymer blends. For binary polymer blends, MAF, normally is located partially inside and partially outside the lamellar stacks. However, the quantification of the MAF inside and outside the lamellar stacks has now been provided

  6. Mechanical properties of crossed-lamellar structures in biological shells: A review.

    Science.gov (United States)

    Li, X W; Ji, H M; Yang, W; Zhang, G P; Chen, D L

    2017-10-01

    The self-fabrication of materials in nature offers an alternate and powerful solution towards the grand challenge of designing advanced structural materials, where strength and toughness are always mutually exclusive. Crossed-lamellar structures are the most common microstructures in mollusks that are composed of aragonites and a small amount of organic materials. Such a distinctive composite structure has a fracture toughness being much higher than that of pure carbonate mineral. These structures exhibiting complex hierarchical microarchitectures that span several sub-level lamellae from microscale down to nanoscale, can be grouped into two types, i.e., platelet-like and fiber-like crossed-lamellar structures based on the shapes of basic building blocks. It has been demonstrated that these structures have a great potential to strengthen themselves during deformation. The observed underlying toughening mechanisms include microcracking, channel cracking, interlocking, uncracked-ligament bridging, aragonite fiber bridging, crack deflection and zig-zag, etc., which play vital roles in enhancing the fracture resistance of shells with the crossed-lamellar structures. The exploration and utilization of these important toughening mechanisms have attracted keen interests of materials scientists since they pave the way for the development of bio-inspired advanced composite materials for load-bearing structural applications. This article is aimed to review the characteristics of hierarchical structures and the mechanical properties of two kinds of crossed-lamellar structures, and further summarize the latest advances and biomimetic applications based on the unique crossed-lamellar structures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. HCP to FCT + precipitate transformations in lamellar gamma-titanium aluminide alloys

    Science.gov (United States)

    Karadge, Mallikarjun Baburao

    Fully lamellar gamma-TiAl [alpha2(HCP) + gamma(FCT)] based alloys are potential structural materials for aerospace engine applications. Lamellar structure stabilization and additional strengthening mechanisms are major issues in the ongoing development of titanium aluminides due to the microstructural instability resulting from decomposition of the strengthening alpha 2 phase. This work addresses characterization of multi-component TiAl systems to identify the mechanism of lamellar structure refinement and assess the effects of light element additions (C and Si) on creep deformation behavior. Transmission electron microscopy studies directly confirmed for the first time that, fine lamellar structure is formed by the nucleation and growth of a large number of basal stacking faults on the 1/6 dislocations cross slipping repeatedly into and out of basal planes. This lamellar structure can be tailored by modifying jog heights through chemistry and thermal processing. alpha 2 → gamma transformation during heating (investigated by differential scanning calorimetry and X-ray diffraction) is a two step process involving the formation of a novel disordered FCC gamma' TiAl [with a(gamma') = c(gamma)] as an intermediate phase followed by ordering. Addition of carbon and silicon induced Ti2AlC H-type carbide precipitation inside the alpha2 lath and Ti 5(Al,Si)3 zeta-type silicide precipitation at the alpha 2/gamma interface. The H-carbides preserve alpha2/gamma type interfaces, while zeta-silicide precipitates restrict ledge growth and interfacial sliding enabling strong resistance to creep deformation.

  8. Lamellar γ-AlOOH architectures: Synthesis and application for the removal of HCN

    International Nuclear Information System (INIS)

    Hou Hongwei; Zhu You; Tang Gangling; Hu Qingyuan

    2012-01-01

    Using hexadecyl trimethyl ammonium bromide (CTAB) as a structure-directing agent and precipitator, the complete synthesis of lamellar γ-AlOOH architectures was successfully accomplished via a hydrothermal route. Different product structures were obtained by varying the molar ratio of aluminum nitrate and CTAB. Several techniques, including X-ray powder diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry thermal analysis, were used to characterize the products. The effects of CTAB concentration, reaction temperature and time, and the molar ratio of Al 3+ /CTAB on the product morphologies were investigated. The nitrogen adsorption and desorption measurements indicated that the γ-AlOOH architectures possess a Brunauer–Emmett–Teller surface area of approximately 75.02 m 2 /g. It was also demonstrated that 10 mg γ-AlOOH architectures can remove 45.3% of the HCN (1.68 μg/mL) from model wastewater. When 0.03 mg/cig γ-AlOOH architectures were combined with cigarette paper, 8.12% of the present HCN was adsorbed. These results indicate that lamellar γ-AlOOH architectures may be a potential adsorbent for removing HCN from highly toxic pollutant solutions and harmful cigarette smoke. Highlights: ► Hexadecyl trimethyl ammonium bromide (CTAB) was used as a structure-directing agent and precipitator. ► Hydrothermal treatment enables growth of lamellar γ-AlOOH architectures. ► Lamellar γ-AlOOH architectures were demonstrated to exhibit high BET surface area and excellent adsorptive capacity. ► HCN in contaminated water and cigarette smoke can be effectively removed by the prepared lamellar γ-AlOOH superstructures.

  9. Electrochemical properties and diffusion of a redox active surfactant incorporated in bicontinuous cubic and lamellar phase

    Energy Technology Data Exchange (ETDEWEB)

    Kostela, J. [Uppsala University, Department of Physical Chemistry, Box 579, S-75123 Uppsala (Sweden)]. E-mail: johan.kostela@fki.uu.se; Elmgren, M. [Uppsala University, Department of Physical Chemistry, Box 579, S-75123 Uppsala (Sweden); Almgren, M. [Uppsala University, Department of Physical Chemistry, Box 579, S-75123 Uppsala (Sweden)

    2005-05-30

    The objective of this study was to investigate the electrochemical behaviour of the divalent redox active surfactant, N-cetyl-N'-methylviologen (CMV), in bicontinuous cubic and lamellar phases. The liquid crystalline phases were prepared from the system glycerolmonooleate (GMO)-water (and brine)-cationic surfactant. A comparison of the phase behaviour of GMO with the monovalent cetyltrimethylammonium bromide (CTAB) and the divalent CMV surfactant showed that the surfactants gave about the same effect at the same surface charge density. The electrochemical measurements were made with a mixture of CTAB and CMV as the surfactant. Cyclic voltammetry was used to study the electrochemistry of CMV incorporated in the cubic and lamellar phases that were spread on a gold electrode. The E {sup 0}-values in the cubic samples were more negative (-0.55 V versus SCE) than in the lamellar samples (-0.53 V versus SCE). This can be explained by the higher charge density in the lamellar phase. The diffusion coefficients were also measured in the cubic phase. The mass transport is slowed down about fifty times in the cubic phase compared to in the pure electrolyte. The concentration dependence on the diffusion coefficient was also investigated. No electron hopping could be observed, which suggest that diffusional movement of the redox probe is the main source of charge transport. By placing the samples on a conducting glass slide, spectroelectrochemical investigations were performed. In the lamellar phase strong dimerization was detected at high concentration of viologen, but much less in the cubic phase.

  10. Annotation of Regular Polysemy

    DEFF Research Database (Denmark)

    Martinez Alonso, Hector

    Regular polysemy has received a lot of attention from the theory of lexical semantics and from computational linguistics. However, there is no consensus on how to represent the sense of underspecified examples at the token level, namely when annotating or disambiguating senses of metonymic words...... and metonymic. We have conducted an analysis in English, Danish and Spanish. Later on, we have tried to replicate the human judgments by means of unsupervised and semi-supervised sense prediction. The automatic sense-prediction systems have been unable to find empiric evidence for the underspecified sense, even...

  11. Regularity of Minimal Surfaces

    CERN Document Server

    Dierkes, Ulrich; Tromba, Anthony J; Kuster, Albrecht

    2010-01-01

    "Regularity of Minimal Surfaces" begins with a survey of minimal surfaces with free boundaries. Following this, the basic results concerning the boundary behaviour of minimal surfaces and H-surfaces with fixed or free boundaries are studied. In particular, the asymptotic expansions at interior and boundary branch points are derived, leading to general Gauss-Bonnet formulas. Furthermore, gradient estimates and asymptotic expansions for minimal surfaces with only piecewise smooth boundaries are obtained. One of the main features of free boundary value problems for minimal surfaces is t

  12. Regularities of radiation heredity

    International Nuclear Information System (INIS)

    Skakov, M.K.; Melikhov, V.D.

    2001-01-01

    One analyzed regularities of radiation heredity in metals and alloys. One made conclusion about thermodynamically irreversible changes in structure of materials under irradiation. One offers possible ways of heredity transmittance of radiation effects at high-temperature transformations in the materials. Phenomenon of radiation heredity may be turned to practical use to control structure of liquid metal and, respectively, structure of ingot via preliminary radiation treatment of charge. Concentration microheterogeneities in material defect structure induced by preliminary irradiation represent the genetic factor of radiation heredity [ru

  13. Ceratoplastia endotelial lamelar profunda em distrofia de Fuchs: relato de caso Deep lamellar endothelial keratoplasty in Fuchs' dystrophy: case report

    Directory of Open Access Journals (Sweden)

    Fernando Trench de Oliveira Komatsu

    2004-08-01

    Full Text Available Descrever o caso de paciente portador de distrofia de Fuchs submetido a ceratoplastia endotelial lamelar profunda. O procedimento cirúrgico foi realizado no olho direito em um caso de distrofia de Fuchs com falência endotelial. Realizou-se incisão límbica superior, o estroma corneano foi delaminado e um disco lamelar de 8,5 mm com 0,150 mm de espessura, contendo estroma, membrana de Descemet e endotélio, foi transplantado sem sutura corneana. Foram avaliados: acuidade visual sem e com correção, biomicroscopia, topografia, paquimetria ultra-sônica e densidade endotelial. A paciente apresentava na avaliação pré-operatória acuidade visual com correção de 20/100 (+4,00 DE -3,25 DC x 60º, astigmatismo de 6,6 dioptrias (37,5 a 12º x 44,1 a 102º, espessura paquimétrica de 0,625 mm e contagem endotelial de 720 cel/mm². Após três meses da cirurgia, apresentava-se com acuidade visual com correção de 20/30 (-1,25 DE -0,50 DC x 45º, astigmatismo regular de 1,0 dioptria (37,2 a 75º x 38,2 a 165º, espessura paquimétrica de 0,503 mm e contagem endotelial de 2447 cel/mm². Observaram-se como complicações: corte inadvertido da íris, má coaptação de bordas, dobras do disco doador e nébula na interface. Os resultados preliminares sugerem que a ceratoplastia endotelial lamelar posterior é uma alternativa para o tratamento cirúrgico da distrofia de Fuchs com falência endotelial. Seguimento mais prolongado e maior número de casos são necessários para melhor entendimento e caracterização desta técnica e de suas repercussões.To report a case of deep lamellar endothelial keratoplasty (DLEK technique applied to a patient with Fuchs' dystrophy. The surgical procedure was performed on the right eye for a case of Fuchs' dystrophy with endothelial failure. Through a 9 mm self-sealing scleral tunnel incision, a stromal pocket was dissected at 0.35 mm depth. A 8.5 mm lamellar donor disc with 0.150 mm thickness, containing posterior

  14. Modeling creep deformation of a two-phase TiAI/Ti3Al alloy with a lamellar microstructure

    Science.gov (United States)

    Bartholomeusz, Michael F.; Wert, John A.

    1994-10-01

    A two-phase TiAl/Ti3Al alloy with a lamellar microstructure has been previously shown to exhibit a lower minimum creep rate than the minimum creep rates of the constituent TiAl and Ti3Al single-phase alloys. Fiducial-line experiments described in the present article demonstrate that the creep rates of the constituent phases within the two-phase TiAl/Ti3Al lamellar alloy tested in compression are more than an order of magnitude lower than the creep rates of single-phase TiAl and Ti3Al alloys tested in compression at the same stress and temperature. Additionally, the fiducial-line experiments show that no interfacial sliding of the phases in the TiAl/Ti3Al lamellar alloy occurs during creep. The lower creep rate of the lamellar alloy is attributed to enhanced hardening of the constituent phases within the lamellar microstructure. A composite-strength model has been formulated to predict the creep rate of the lamellar alloy, taking into account the lower creep rates of the constituent phases within the lamellar micro-structure. Application of the model yields a very good correlation between predicted and experimentally observed minimum creep rates over moderate stress and temperature ranges.

  15. Effective field theory dimensional regularization

    International Nuclear Information System (INIS)

    Lehmann, Dirk; Prezeau, Gary

    2002-01-01

    A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed

  16. Effective field theory dimensional regularization

    Science.gov (United States)

    Lehmann, Dirk; Prézeau, Gary

    2002-01-01

    A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed.

  17. 75 FR 76006 - Regular Meeting

    Science.gov (United States)

    2010-12-07

    ... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

  18. Evaluation of Microemulsion and Lamellar Liquid Crystalline Systems for Transdermal Zidovudine Delivery.

    Science.gov (United States)

    Carvalho, André Luis Menezes; Silva, José Alexsandro da; Lira, Ana Amélia Moreira; Conceição, Tamara Matos Freire; Nunes, Rogéria de Souza; de Albuquerque Junior, Ricardo Luiz Cavalcanti; Sarmento, Victor Hugo Vitorino; Leal, Leila Bastos; de Santana, Davi Pereira

    2016-07-01

    This study proposed to investigate and to compare colloidal carrier systems containing Zidovudine (3'-azido-3'-deoxythymidine) (AZT) for transdermal administration and optimization of antiretroviral therapy. Microemulsion (ME) and lamellar phase (LP) liquid crystal were obtained and selected from pseudoternary diagrams previously developed. Small-angle X-ray scattering and rheology analysis confirmed the presence of typical ME and liquid crystalline structures with lamellar arrangement, respectively. Both colloidal carrier systems, ME, and LP remained stable, homogeneous, and isotropic after AZT addition. In vitro permeation study (using pig ear skin) showed that the amount of permeated drug was higher for ME compared to the control and LP, obtaining a permeation enhancing effect on the order of approximately 2-fold (p drug permeation without causing apparent skin irritation. On the order hand, LP functioned as a drug reservoir reducing AZT partitioning into the skin. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  19. Theory of X-ray scattering by strongly distorted aging alloys with lamellar distribution of inclusions

    International Nuclear Information System (INIS)

    Barabash, R.I.; Krivoglaz, M.A.; AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1981-01-01

    The X-ray scattering by strongly distorted heterogeneous alloys containing inclusions of new phase particles is discussed. Two models describing the lamellar structure with various orientation of inclusion axes in different layers are studied. In the first model the dimensions of inclusions are small in comparison with the layer thickness and they are randomly distributed in it, in the second model lamellar inclusions stretch through the whole layer. It is shown that in both models the Debye broadened line intensity distribution consists of overlapping Lorentz curves. A case of inclusions oriented along directions [100] and layers perpendicular to axes [110] is analyzed in detail. The results obtained for this case are compared with experimental results for the Cu-Be alloy

  20. Closed compact Taylor's droplets in a phase-separated lamellar-sponge mixture under shear flow

    Science.gov (United States)

    Courbin, L.; Cristobal, G.; Rouch, J.; Panizza, P.

    2001-09-01

    We have studied by optical microscopy, small-angle light scattering, and rheology, the behavior under shear flow of a phase-separated lamellar-sponge (Lα - L3) ternary mixture. We observe in the Lα-rich region (ΦLα > 80%) the existence of a Newtonian assembly made of closed compact monodisperse lamellar droplets immersed in the sponge phase. Contrary to the classical onion glassy texture obtained upon shearing Lα phases, the droplet size scales herein as dot gamma-1, the inverse of the shear rate. This result is in good agreement with Taylor's picture. Above a critical shear rate, dot gammac, the droplets organize to form a single colloidal crystal whose lattice size varies as dot gamma-1/3. To the memory of Tess Melissa P.

  1. Creep mechanisms of fully-lamellar TiAl based upon interface sliding

    International Nuclear Information System (INIS)

    Hsiung, L.M.; Nieh, T.G.

    1999-01-01

    Deformation mechanisms of fully lamellar TiAl with a refined microstructure (γ lamellae: 100 approximately 300 nm thick, α 2 lamellae: 10 approximately 50 nm thick) crept at 760 C have been investigated. As a result of a fine structure, the motion and multiplication of lattice dislocations within both γ and α 2 lamellae are limited at low creep stresses ( 2 and γ/γ interfaces (i.e., interface sliding) is proposed to be the dominant deformation mechanism at low stresses. Lattice dislocations impinged on lamellar interfaces are found to be the major obstacles impeding the motion of interfacial dislocations. The number of impinged lattice dislocations increases as the applied stress increases and, subsequently, causes the pileup of interfacial dislocations along the interfaces. Accordingly, deformation twinning activated by the pileup of interfacial dislocations is proposed to be the dominant deformation mechanism at high stresses (>400 MPa)

  2. Phase-field-lattice Boltzmann study for lamellar eutectic growth in a natural convection melt

    Directory of Open Access Journals (Sweden)

    Ang Zhang

    2017-11-01

    Full Text Available In the present study, the influence of natural convection on the lamellar eutectic growth is determined by a phase-field-lattice Boltzmann study for Al-Cu eutectic alloy. The mass difference resulting from concentration difference led to the fluid flow, and a robust parallel and adaptive mesh refinement algorithm was employed to improve the computational efficiency without any compromising accuracy. Results show that the existence of natural convection would affect the growth undercooling and thus control the interface shape by adjusting the lamellar width. In particular, by alternating the magnitude of the solute expansion coefficient, the strength of the natural convection is changed. Corresponding microstructure patterns are discussed and compared with those under no-convection conditions.

  3. Creep characteristics of a hypoeutectic Mg-Ca binary alloy with a near-fully lamellar microstructure

    International Nuclear Information System (INIS)

    Terada, Yoshihiro; Tsukahara, Masashi; Shibayama, Atsushi; Murata, Yoshinori; Morinaga, Masahiko

    2011-01-01

    Highlights: → We develop a hypoeutectic Mg-Ca cast alloy with a near-fully lamellar microstructure. → Dislocations are introduced within the lamellar microstructure during casting. → The dislocation segments in the α-Mg plates are located on the basal planes. → Creep of the alloy is ascribed to the easy glide of the introduced dislocations. -- The creep behavior of a hypoeutectic Mg-14.8 mass% Ca cast alloy with an α-Mg/C14-Mg 2 Ca near-fully lamellar microstructure was investigated at 473 K. Transmission electron microscopy shows that dislocations are introduced within the lamellar microstructure of the alloy during casting; the dislocation segments in the α-Mg plates are located on basal planes. The stress exponent of the creep rate is unity in the early stage of transient creep. Creep deformation of the alloy is ascribed to the easy glide of the introduced dislocations.

  4. Selection of regularization parameter for l1-regularized damage detection

    Science.gov (United States)

    Hou, Rongrong; Xia, Yong; Bao, Yuequan; Zhou, Xiaoqing

    2018-06-01

    The l1 regularization technique has been developed for structural health monitoring and damage detection through employing the sparsity condition of structural damage. The regularization parameter, which controls the trade-off between data fidelity and solution size of the regularization problem, exerts a crucial effect on the solution. However, the l1 regularization problem has no closed-form solution, and the regularization parameter is usually selected by experience. This study proposes two strategies of selecting the regularization parameter for the l1-regularized damage detection problem. The first method utilizes the residual and solution norms of the optimization problem and ensures that they are both small. The other method is based on the discrepancy principle, which requires that the variance of the discrepancy between the calculated and measured responses is close to the variance of the measurement noise. The two methods are applied to a cantilever beam and a three-story frame. A range of the regularization parameter, rather than one single value, can be determined. When the regularization parameter in this range is selected, the damage can be accurately identified even for multiple damage scenarios. This range also indicates the sensitivity degree of the damage identification problem to the regularization parameter.

  5. Ensemble manifold regularization.

    Science.gov (United States)

    Geng, Bo; Tao, Dacheng; Xu, Chao; Yang, Linjun; Hua, Xian-Sheng

    2012-06-01

    We propose an automatic approximation of the intrinsic manifold for general semi-supervised learning (SSL) problems. Unfortunately, it is not trivial to define an optimization function to obtain optimal hyperparameters. Usually, cross validation is applied, but it does not necessarily scale up. Other problems derive from the suboptimality incurred by discrete grid search and the overfitting. Therefore, we develop an ensemble manifold regularization (EMR) framework to approximate the intrinsic manifold by combining several initial guesses. Algorithmically, we designed EMR carefully so it 1) learns both the composite manifold and the semi-supervised learner jointly, 2) is fully automatic for learning the intrinsic manifold hyperparameters implicitly, 3) is conditionally optimal for intrinsic manifold approximation under a mild and reasonable assumption, and 4) is scalable for a large number of candidate manifold hyperparameters, from both time and space perspectives. Furthermore, we prove the convergence property of EMR to the deterministic matrix at rate root-n. Extensive experiments over both synthetic and real data sets demonstrate the effectiveness of the proposed framework.

  6. Soft solution synthesis and intense visible photoluminescence of lamellar zinc oxide hybrids

    International Nuclear Information System (INIS)

    Sağlam, Özge

    2013-01-01

    Graphical abstract: -- In this study, we demonstrate the synthesis of layered zinc oxide films intercalated with dodecyl sulphate ions by a simple soft solution process. The presence of potassium (K + ) and lithium (Li + ) ions in the precursor solution of layered zinc hydroxide resulted in lamellar hybrid zinc oxide films instead of layered zinc hydroxides. On the other hand, the addition of nickel phthalocyanine induces zinc hydroxide host layers which exhibit an intense blue emission. This is also promoted by K + and Li + ions

  7. Hierarchical Formation of Fibrillar and Lamellar Self-Assemblies from Guanosine-Based Motifs

    Directory of Open Access Journals (Sweden)

    Paolo Neviani

    2010-01-01

    Full Text Available Here we investigate the supramolecular polymerizations of two lipophilic guanosine derivatives in chloroform by light scattering technique and TEM experiments. The obtained data reveal the presence of several levels of organization due to the hierarchical self-assembly of the guanosine units in ribbons that in turn aggregate in fibrillar or lamellar soft structures. The elucidation of these structures furnishes an explanation to the physical behaviour of guanosine units which display organogelator properties.

  8. A case of acute postoperative keratitis after deep anterior lamellar keratoplasty by multidrug resistant Klebsiella

    Directory of Open Access Journals (Sweden)

    Leena Bajracharya

    2015-01-01

    Full Text Available A healthy lady of 42 years underwent deep anterior lamellar keratoplasty for granular dystrophy. The very next day, it was complicated by development of infectious keratitis. The organism was identified as multidrug resistant Klebsiella pneumoniae. Donor corneal button may be implicated in the transmission of infection in an otherwise uneventful surgery and follow-up. Nosocomial infections are usually severe, rapidly progressive and difficult to treat. Finally, the lady had to undergo therapeutic penetrating keratoplasty for complete resolution of infection.

  9. The Evolution of Splint Armour in Georgia and Byzantium: Lamellar and Scale Armour in the 10th-12th Centuries

    OpenAIRE

    TSURTSUMIA, Mamuka

    2011-01-01

    Byzantine technology was part of the military technology that existed in vast areas of Eurasia; hence study of the armament of its neighbours is important.The purpose of the present paper is to add new data about Byzantium’s Caucasian neighbour (namely, Georgia). Besides that, it also includes certain views about the stages of the evolution and provenance of splint (scale and lamellar) armour. This paper also attempts to clarify the difference between banded and linear suits of lamellar armou...

  10. In situ ultrahigh-resolution optical coherence tomography characterization of eye bank corneal tissue processed for lamellar keratoplasty.

    Science.gov (United States)

    Brown, Jamin S; Wang, Danling; Li, Xiaoli; Baluyot, Florence; Iliakis, Bernie; Lindquist, Thomas D; Shirakawa, Rika; Shen, Tueng T; Li, Xingde

    2008-08-01

    To use optical coherence tomography (OCT) as a noninvasive tool to perform in situ characterization of eye bank corneal tissue processed for lamellar keratoplasty. A custom-built ultrahigh-resolution OCT (UHR-OCT) was used to characterize donor corneal tissue that had been processed for lamellar keratoplasty. Twenty-seven donor corneas were analyzed. Four donor corneas were used as controls, whereas the rest were processed into donor corneal buttons for lamellar transplantation by using hand dissection, a microkeratome, or a femtosecond laser. UHR-OCT was also used to noninvasively characterize and monitor the viable corneal tissue immersed in storage medium over 3 weeks. The UHR-OCT captured high-resolution images of the donor corneal tissue in situ. This noninvasive technique showed the changes in donor corneal tissue morphology with time while in storage medium. The characteristics of the lamellar corneal tissue with each processing modality were clearly visible by UHR-OCT. The in situ characterization of the femtosecond laser-cut corneal tissue was noted to have more interface debris than shown by routine histology. The effects of the femtosecond laser microcavitation bubbles on the corneal tissue were well visualized at the edges of the lamellar flap while in storage medium. The results of our feasibility study show that UHR-OCT can provide superb, in situ microstructural characterization of eye bank corneal tissue noninvasively. The UHR-OCT interface findings and corneal endothelial disc thickness uniformity analysis are valuable information that may be used to optimize the modalities and parameters for lamellar tissue processing. The UHR-OCT is a powerful approach that will allow us to further evaluate the tissue response to different processing techniques for posterior lamellar keratoplasty. It may also provide information that can be used to correlate with postoperative clinical outcomes. UHR-OCT has the potential to become a routine part of tissue

  11. Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities.

    Science.gov (United States)

    Bilgihan, Kamil; Ozdek, Sengül C; Sari, Ayça; Hasanreisoğlu, Berati

    2006-08-01

    To evaluate excimer laser-assisted anterior lamellar keratoplasty to augment thin corneas as in keratoconus ( .05). This technique presents a different modality for the treatment of keratoconus, post-LASIK corneal problems, and other corneal stromal opacities with anterior lamellar keratoplasty. Additional studies with more patients and longer follow-up will help determine the role of this technique as a substitute for penetrating keratoplasty in these patients.

  12. One-step exfoliation and surface modification of lamellar hydroxyapatite by intercalation of glucosamine

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Honglin [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Li, Wei; Ji, Dehui [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan, 063009 (China); Xiong, Guangyao, E-mail: xiongguangyao@163.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zhu, Yong [School of Chemical Engineering, Tianjin University, Tianjin, 300072 (China); Li, Lili; Han, Ming [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Wu, Caoqun [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China)

    2016-04-15

    Effective exfoliation is crucial to the application of layered materials in many fields. Herein, we report a novel effective, scalable, and ecofriendly method for the exfoliation of lamellar HAp by glucosamine intercalation such that individual HAp nanoplates can be obtained. The as-exfoliated HAp nanoplates were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric (TG) analysis. It is found that the glucosamine intercalation not only results in complete exfoliation of lamellar HAp but also introduces the glucosamine molecules onto the surface of individual HAp nanoplates, thus obtaining separated glucosamine-grafted HAp nanoplates (Glu-HAps). Results from MTT assay demonstrate that glucosamine grafting on HAp nanoplates greatly improves the cell growth and proliferation as compared to nongrafted HAp counterparts. - Highlights: • Glucosamine was used as intercalation agent to exfoliate lamellar hydroxyapatite. • Glucosamine was grafted onto the as-exfoliated nanoplate-like hydroxyapatite. • Exfoliation and surface grafting were accomplished in one step. • Glucosamine-grafted HAp showed improved biocompatibility over nongrafted one.

  13. Fourier method for modeling slanted lamellar gratings of arbitrary end-surface shapes in conical mounting.

    Science.gov (United States)

    Li, Lifeng

    2015-10-01

    An efficient modal method for numerically modeling slanted lamellar gratings of isotropic dielectric or metallic media in conical mounting is presented. No restrictions are imposed on the slant angle and the length of the lamellae. The end surface of the lamellae can be arbitrary, subject to certain restrictions. An oblique coordinate system that is adapted to the slanted lamella sidewalls allows the most efficient way of representing and manipulating the electromagnetic fields. A translational coordinate system that is based on the oblique Cartesian coordinate system adapts to the end-surface profile of the lamellae, so that the latter can be handled simply and easily. Moreover, two matrix eigenvalue problems of size 2N × 2N, one for each fundamental polarization of the electromagnetic fields in the periodic lamellar structure, where N is the matrix truncation number, are derived to replace the 4N × 4N eigenvalue problem that has been used in the literature. The core idea leading to this success is the polarization decomposition of the electromagnetic fields inside the periodic lamellar region when the fields are expressed in the oblique translational coordinate system.

  14. On the mechanism of crack propagation resistance of fully lamellar TiAl alloy

    International Nuclear Information System (INIS)

    Cao, R.; Yao, H.J.; Chen, J.H.; Zhang, J.

    2006-01-01

    The study was done using notched two-colony thick tensile specimens of a directionally solidified cast fully lamellar TiAl alloy. In-situ observations of fracture processes in scanning electron microscope (SEM) were combined with section-to-section related observations of fracture surfaces to investigate the crack growth process. Finite element method (FEM) calculations are carried out to evaluate the stresses for propagating cracks. The results reveal that: (1) the reason why enhancement of applied load is required to propagate the main crack, was attributed to that the main crack observed at the surface did not extend all the way through the specimen's thickness thus the stress field was still controlled by the notch, in which a definite stress required for extending a crack tip should be kept by increasing the applied load. (2) Crack propagation resistance is enhanced at colony boundaries, only when a change occurs from an inter-lamellar propagation to a trans-lamellar propagation (3) Ligament bridging toughening phenomena can be integrated into aforementioned mechanism. As a whole the processes of new crack nucleation with bridging ligament formation decreases the crack propagation resistance rather than increasing it. (4) In case the majority of microcracks are surface cracks, the effect of microcrack shielding is not obvious

  15. Evaluation of Biaxial Mechanical Properties of Aortic Media Based on the Lamellar Microstructure

    Directory of Open Access Journals (Sweden)

    Hadi Taghizadeh

    2015-01-01

    Full Text Available Evaluation of the mechanical properties of arterial wall components is necessary for establishing a precise mechanical model applicable in various physiological and pathological conditions, such as remodeling. In this contribution, a new approach for the evaluation of the mechanical properties of aortic media accounting for the lamellar structure is proposed. We assumed aortic media to be composed of two sets of concentric layers, namely sheets of elastin (Layer I and interstitial layers composed of mostly collagen bundles, fine elastic fibers and smooth muscle cells (Layer II. Biaxial mechanical tests were carried out on human thoracic aortic samples, and histological staining was performed to distinguish wall lamellae for determining the dimensions of the layers. A neo-Hookean strain energy function (SEF for Layer I and a four-parameter exponential SEF for Layer II were allocated. Nonlinear regression was used to find the material parameters of the proposed microstructural model based on experimental data. The non-linear behavior of media layers confirmed the higher contribution of elastic tissue in lower strains and the gradual engagement of collagen fibers. The resulting model determines the nonlinear anisotropic behavior of aortic media through the lamellar microstructure and can be assistive in the study of wall remodeling due to alterations in lamellar structure during pathological conditions and aging.

  16. Reverse osmosis desalination of chitosan cross-linked graphene oxide/titania hybrid lamellar membranes.

    Science.gov (United States)

    Deng, Hui; Sun, Penzhan; Zhang, Yingjiu; Zhu, Hongwei

    2016-07-08

    With excellent mass transport properties, graphene oxide (GO)-based lamellar membranes are believed to have great potential in water desalination. In order to quantify whether GO-based membranes are indeed suitable for reverse osmosis (RO) desalination, three sub-micrometer thick GO-based lamellar membranes: GO-only, reduced GO (RGO)/titania (TO) nanosheets and RGO/TO/chitosan (CTS) are prepared, and their RO desalination performances are evaluated in a home-made RO test apparatus. The photoreduction of GO by TO improves the salt rejection, which increases slowly with the membrane thickness. The RGO/TO/CTS hybrid membranes exhibit higher rejection rates of only about 30% (greater than threefold improvement compared with a GO-only membrane) which is still inferior compared to other commercial RO membranes. The low rejection rates mainly arise from the pressure-induced weakening of the ion-GO interlayer interactions. Despite the advantages of simple, low-cost preparation, high permeability and selectivity of GO-based lamellar membranes, as the current desalination performances are not high enough to afford practical application, there still remains a great challenge to realize high performance separation membranes for water desalination applications.

  17. Finite element analysis for the initiation of lamellar tearing in welded joints

    International Nuclear Information System (INIS)

    Krieg, R.D.; Thomas, R.K.

    1980-01-01

    A numerical procedure using the finite element method is presented for predicting the initiation of lamellar tearing in fillet welded T-joints commonly employed in large structures. Starting with a prescribed geometry, the welding process is approximated by a known time-dependent volumetric heat source which simulates the arc heating and deposition of liquid metal. The transient nonlinear thermal and stress problems are then solved using finite element computer codes. Results of the elastic-plastic stress analysis are presented showing a predicted region of incipient lamellar tearing based on a ductile fracture theory which qualitatively agrees with the size and location of tears typically observed in photomicrographs. Additional insight into post failure crack length and stability is presented based on a simplified linear elastic fracture mechanics approach. Although the analysis procedure shows signs of promise, several weak points in the model are pointed out which must be improved before lamellar tearing can be quantified in an approach of this general type

  18. Oligosaccharides and glycolipids addition in charged lamellar phases; Addition d`oligosaccharides et de glycolipides dans des phases lamellaires chargees

    Energy Technology Data Exchange (ETDEWEB)

    Ricoul, F

    1997-09-26

    The aim of this work is to study the addition of oligosaccharides and glycolipids in lamellar phases of the cationic surfactant DDAB (di-dodecyl-dimethyl-ammonium bromide). Two steps have been followed: the determination of phases prisms and the thermodynamic interpretation in terms of molecular interactions. In order to characterize these systems, two new experimental small angle scattering methods have been perfected: 1) a neutron scattering contrast variation method which allows to study the adsorption of aqueous solution in bilayers and 2) a capillary concentration gradient method to establish directly and quantitatively the phases diagrams of ternary systems by X rays scattering. It has been pointed out that the oligosaccharides induce a depletion attractive force on the lamellar-lamellar equilibrium of the DDAB when they are excluded of the most concentrated phase. For the two studied glycolipids: 2-O lauroyl-saccharose and N-lauroyl N-nonyl lactitol, the ternary phase diagrams water-DDAB-glycolipid have been established in terms of temperature. Critical points at ambient temperature have been given. The osmotic pressure in concentrated lamellar phases has been measured. It has been shown that glycolipids increase the hydration repulsion at short distance and that the electrostatic repulsion is outstanding and unchanged at high distance if there is at less 1 mole percent of ionic surfactant. In a dilute solution, glycolipids decrease the maximum swelling of lamellar phases, with a competition between the lamellar phase and the micellae dilute phase for water. (O.M.). 165 refs.

  19. Merging Bottom-Up with Top-Down: Continuous Lamellar Networks and Block Copolymer Lithography

    Science.gov (United States)

    Campbell, Ian Patrick

    Block copolymer lithography is an emerging nanopatterning technology with capabilities that may complement and eventually replace those provided by existing optical lithography techniques. This bottom-up process relies on the parallel self-assembly of macromolecules composed of covalently linked, chemically distinct blocks to generate periodic nanostructures. Among the myriad potential morphologies, lamellar structures formed by diblock copolymers with symmetric volume fractions have attracted the most interest as a patterning tool. When confined to thin films and directed to assemble with interfaces perpendicular to the substrate, two-dimensional domains are formed between the free surface and the substrate, and selective removal of a single block creates a nanostructured polymeric template. The substrate exposed between the polymeric features can subsequently be modified through standard top-down microfabrication processes to generate novel nanostructured materials. Despite tremendous progress in our understanding of block copolymer self-assembly, continuous two-dimensional materials have not yet been fabricated via this robust technique, which may enable nanostructured material combinations that cannot be fabricated through bottom-up methods. This thesis aims to study the effects of block copolymer composition and processing on the lamellar network morphology of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) and utilize this knowledge to fabricate continuous two-dimensional materials through top-down methods. First, block copolymer composition was varied through homopolymer blending to explore the physical phenomena surrounding lamellar network continuity. After establishing a framework for tuning the continuity, the effects of various processing parameters were explored to engineer the network connectivity via defect annihilation processes. Precisely controlling the connectivity and continuity of lamellar networks through defect engineering and

  20. The Electrochemical Assembly of Semiconducting Organic-Inorganic Lamellar Domains for Photovoltaics

    Science.gov (United States)

    Herman, David John

    This dissertation investigates the one-step electrodeposition of alternating nanoscale domains of n-type ZnO and p-type organic molecules for photovoltaics. In such hybrid photovoltaic systems, a nanoscale lamellar periodicity of 5-10 nm between electron donor and electron acceptor materials is ideal for efficient exciton separation. In addition, achieving uniform density and substrate-wide alignment of the hybrid lamellar structures with orientation perpendicular to substrate surfaces is important in providing direct pathways for charge carriers to the electrodes. To this end, it is first reported how to control the assembly of the pyrene-based surfactant 1-pyrenebutyric acid (PyBA) with zinc hydroxide (a precursor to the semiconductor ZnO), resulting in a nanoscale lamellar structure with a periodicity of 3.2 nm. By exploring solution chemistry parameters, the surfactant concentration and solvent composition are shown to have the greatest effect on the morphology of lamellar growth. By studying the early nucleation and growth on indium tin oxide (ITO) substrates with 2D grazing incidence small angle X-ray scattering, it is revealed that the lamellae preferentially nucleate parallel to the hydrophilic ITO surface. It is hypothesized that the conductive and more hydrophobic poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) surface increases the affinity for the pyrene functions to the surface, and therefore the oriented growth of the lamellae changes from parallel to perpendicular with respect to the substrate surface. The second part of this thesis investigates the effects of conjugated surfactant design in directing the growth of hybrid lamellar structures by incorporating either a pyrene or terthiophene moiety and varying overall molecular design. It is found that high aspect ratio and amphiphilic surfactants possessing a flexible alkyl spacer between the carboxylic acid and conjugated moiety consistently allow for the controlled and directed

  1. Adaptive Regularization of Neural Classifiers

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Larsen, Jan; Hansen, Lars Kai

    1997-01-01

    We present a regularization scheme which iteratively adapts the regularization parameters by minimizing the validation error. It is suggested to use the adaptive regularization scheme in conjunction with optimal brain damage pruning to optimize the architecture and to avoid overfitting. Furthermo......, we propose an improved neural classification architecture eliminating an inherent redundancy in the widely used SoftMax classification network. Numerical results demonstrate the viability of the method...

  2. 75 FR 53966 - Regular Meeting

    Science.gov (United States)

    2010-09-02

    ... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the offices of the Farm...

  3. Online co-regularized algorithms

    NARCIS (Netherlands)

    Ruijter, T. de; Tsivtsivadze, E.; Heskes, T.

    2012-01-01

    We propose an online co-regularized learning algorithm for classification and regression tasks. We demonstrate that by sequentially co-regularizing prediction functions on unlabeled data points, our algorithm provides improved performance in comparison to supervised methods on several UCI benchmarks

  4. Indefinite metric and regularization of electrodynamics

    International Nuclear Information System (INIS)

    Gaudin, M.

    1984-06-01

    The invariant regularization of Pauli and Villars in quantum electrodynamics can be considered as deriving from a local and causal lagrangian theory for spin 1/2 bosons, by introducing an indefinite metric and a condition on the allowed states similar to the Lorentz condition. The consequences are the asymptotic freedom of the photon's propagator. We present a calcultion of the effective charge to the fourth order in the coupling as a function of the auxiliary masses, the theory avoiding all mass divergencies to this order [fr

  5. A Study of the Confinement Induced Sponge to Lamellar Phase Transformation by Direct Force Measurement

    International Nuclear Information System (INIS)

    Antelmi, David

    1996-10-01

    The interactions between two macroscopic walls immersed in an isotropic symmetric sponge phase (L_3) at different volume fractions, Φ, were studied with a surface force apparatus. The purpose of these experiments was to investigate the behaviour of the sponge phase when confined between two smooth rigid surfaces. Particular attention was given to investigating this behaviour as the bulk transition to the lamellar phase (L_α) was approached. At temperatures far from the L_3/L_α bulk transition temperature, the force-distance profile showed weak oscillations with a periodicity approximately equal to twice the characteristic length, ξ, measured for the sponge phase from small angle x-ray scattering. Furthermore, the oscillations were superimposed on an exponential attractive background that decayed with an order parameter correlation length of 2-3 times ξ The attractive background was explained by the enhancement of the sponge order in the vicinity of the rigid walls. The structural oscillations observed in the force-distance profile, although not completely understood, were discussed in terms of the packing of sponge cells (cell size ξ). The significance of the observed periodicity (2ξ) may indicate the importance of the symmetric nature of the sponge phase. By moving pairs of cells in response to an applied strain, the symmetry of the sponge structure is protected. As the temperature increased towards the L_3/L_α bulk transition temperature, an abrupt change in the force-distance profile was observed at a threshold separation labelled D*_i_n. A different force regime was observed for separations below D*_i_n which oscillated with a periodicity that was twice the reticular spacing, d, for a L_α phase of similar Φ. The force oscillations were superimposed on an attractive background that was almost linear. These observations were consistent with a first order phase transition from the sponge phase to the lamellar phase, induced by the confinement, where the

  6. Mechanical contribution of lamellar and interlamellar elastin along the mouse aorta.

    Science.gov (United States)

    Clark, T E; Lillie, M A; Vogl, A W; Gosline, J M; Shadwick, R E

    2015-10-15

    The mechanical properties of aortic elastin vary regionally, but the microstructural basis for this variation is unknown. This study was designed to identify the relative contributions of lamellar and interlamellar elastin to circumferential load bearing in the mouse thoracic and abdominal aortas. Forces developed in uniaxial tests of samples of fresh and autoclaved aorta were correlated with elastin content and morphology obtained from histology and multiphoton laser scanning microscopy. Autoclaving should render much of the interlamellar elastin mechanically incompetent. In autoclaved tissue force per unit sample width correlated with lamellar elastin content (P≪0.001) but not total elastin content. In fresh tissue at low strain where elastin dominates the mechanical response, forces were higher than in the autoclaved tissue, but force did not correlate with total elastin content. Therefore although interlamellar elastin likely contributed to the stiffness in the fresh aorta, its contribution appeared not in proportion to its quantity. In both fresh and autoclaved tissue, elastin stiffness consistently decreased along the abdominal aorta, a key area for aneurysm development, and this difference could not be fully accounted for on the basis of either lamellar or total elastin content. These findings are relevant to the development of mathematical models of arterial mechanics, particularly for mouse models of arterial diseases involving elastic tissue. In microstructural based models the quantity of each mural constituent determines its contribution to the total response. This study shows elastin's mechanical response cannot necessarily be accounted for on the basis of fibre quantity, orientation, and modulus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Comparison of synthetic glues and 10-0 nylon in rabbit lamellar keratoplasty.

    Science.gov (United States)

    Cho, Soon Young; Kim, Man Soo; Oh, Su Ja; Chung, Sung Kun

    2013-09-01

    To evaluate changes in mean keratometry and to compare wound repair with corneal lamellar grafts in rabbit eyes using human synthetic tissue adhesives and 10-0 nylon. Corneal grafts were made using a 6.0-mm-diameter trephine and blades in the eyes of 15 New Zealand white rabbits. Human fibrin tissue adhesive (Tisseel) was used in group 1, human fibrin tissue adhesive (Beriplast P) was used in group 2, polyethylene glycol adhesive (Coseal) was used in group 3, and 8 bite sutures with 10-0 nylon were used in group 4 (control) for lamellar keratoplasty. Four bite sutures were made with 10-0 nylon in groups 1, 2, and 3. Slit-lamp microscopy and keratometry were performed at 3 days and 1, 2, and 4 weeks after the surgery. Histopathologic and electromicroscopic examinations were performed 4 weeks after the surgery. No inflammation or corneal toxicity was seen in groups 1 and 2. Histologically, a few inflammatory cells were seen in groups 3 and 4. Groups 1, 2, and 3 showed no statistically significant changes in mean keratometry at 4 weeks postoperatively compared with preoperative mean keratometry (Wilcoxon signed-rank test, P = 0.178, 0.208, and 0.889, respectively). The control group showed significant changes in mean keratometry at 4 weeks postoperatively (Wilcoxon signed-rank test, P = 0.018). Human fibrin tissue adhesives were well tolerated in rabbit eyes, with no apparent corneal toxicity. Polyethylene glycol adhesive showed more inflammation and insufficient wound repair compared with human fibrin tissue adhesives. Therefore, human fibrin tissue adhesives can be used as an alternative to sutures in lamellar keratoplasty.

  8. Repair of articular osteochondral defects of the knee joint using a composite lamellar scaffold.

    Science.gov (United States)

    Lv, Y M; Yu, Q S

    2015-04-01

    The major problem with repair of an articular cartilage injury is the extensive difference in the structure and function of regenerated, compared with normal cartilage. Our work investigates the feasibility of repairing articular osteochondral defects in the canine knee joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate (ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells (BMSCs) and assesses its biological compatibility. The bone-cartilage scaffold was prepared as a laminated composite, using hydroxyapatite nanoparticles (nano-HAP)/collagen I/copolymer of polylactic acid-hydroxyacetic acid as the bony scaffold, and sodium hyaluronate/poly(lactic-co-glycolic acid) as the cartilaginous scaffold. Ten-to 12-month-old hybrid canines were randomly divided into an experimental group and a control group. BMSCs were obtained from the iliac crest of each animal, and only those of the third generation were used in experiments. An articular osteochondral defect was created in the right knee of dogs in both groups. Those in the experimental group were treated by implanting the composites consisting of the lamellar scaffold of ß-TCP/col I/col II/BMSCs. Those in the control group were left untreated. After 12 weeks of implantation, defects in the experimental group were filled with white semi-translucent tissue, protruding slightly over the peripheral cartilage surface. After 24 weeks, the defect space in the experimental group was filled with new cartilage tissues, finely integrated into surrounding normal cartilage. The lamellar scaffold of ß-TCP/col I/col II was gradually degraded and absorbed, while new cartilage tissue formed. In the control group, the defects were not repaired. This method can be used as a suitable scaffold material for the tissue-engineered repair of articular cartilage defects. Cite this article: Bone Joint Res 2015;4:56-64. ©2015 The British Editorial Society of Bone & Joint Surgery.

  9. CST simulations of THz Smith–Purcell radiation from a lamellar grating with vacuum gaps

    International Nuclear Information System (INIS)

    Lekomtsev, K.; Karataev, P.; Tishchenko, A.A.; Urakawa, J.

    2015-01-01

    Smith–Purcell radiation (SPR) from a lamellar grating with vacuum gaps was calculated using Computer Simulation Technology (CST) Particle In Cell (PIC) solver. The shapes of the radiation distributions were compared with those of Resonant Diffraction Radiation theory. Study of calculation domain meshing was performed. Influence of a transverse bunch size on the calculation accuracy and an SPR intensity distribution was investigated. Dependencies of the SPR yield on Lorentz factor and grating strip depth were calculated and compared with previously reported theoretical and experimental studies

  10. CuInS[sub 2] with lamellar morphology; 2: Photoelectrochemical behavior of heterogeneous material

    Energy Technology Data Exchange (ETDEWEB)

    Cattarin, S. (Inst. di Polarografia ed Elettrochimica Preparativa del C.N.R., Padova (Italy)); Guerriero, P. (Inst. di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati del C.N.R., Padova (Italy)); Razzini, G. (Applicata del Politecnico di Milano (Italy). Dipt. di Chimica Fisica); Lewerenz, H.J. (Hahn-Meitner-Inst., Berlin (Germany))

    1994-05-01

    Lamellar CuInS[sub 2] material grown in a steep temperature gradient shows heterogeneous composition and complex photoeffects. Besides predominant n-type behavior, the electrode surface has areas with intrinsic or p-type conductivity, the latter usually corresponding to indium-rich regions. An inverted (cathodic) photocurrent is observed at n-type electrodes polarized under accumulation conditions. Both spectral dependence, with a pronounced peak for energies around the bandgap, and quantum yields > 1 suggest that these photoeffects originate from photoconductivity phenomena in the crystal bulk. Variability in electronic properties limits the average performance of the material in solar cells.

  11. Ribbon phase in a phase-separated lyotropic lamellar-sponge mixture under shear flow

    Science.gov (United States)

    Cristobal, G.; Rouch, J.; Panizza, P.; Narayanan, T.

    2001-07-01

    We report the effect of shear flow on a phase-separated system composed of lyotropic lamellar (Lα) and sponge (L3) phases in a mixture of brine, surfactant, and cosurfactant. Optical microscopy, small-angle light, and x-ray scattering measurements are consistent with the existence of a steady state made of multilamellar ribbonlike structures aligned in the flow direction. At high shear rates, these ribbonlike structures become unstable and break up into monodisperse droplets resulting in a shear-thickening transition.

  12. Impacts of clustering on noise-induced spiking regularity in the excitatory neuronal networks of subnetworks.

    Science.gov (United States)

    Li, Huiyan; Sun, Xiaojuan; Xiao, Jinghua

    2015-01-01

    In this paper, we investigate how clustering factors influent spiking regularity of the neuronal network of subnetworks. In order to do so, we fix the averaged coupling probability and the averaged coupling strength, and take the cluster number M, the ratio of intra-connection probability and inter-connection probability R, the ratio of intra-coupling strength and inter-coupling strength S as controlled parameters. With the obtained simulation results, we find that spiking regularity of the neuronal networks has little variations with changing of R and S when M is fixed. However, cluster number M could reduce the spiking regularity to low level when the uniform neuronal network's spiking regularity is at high level. Combined the obtained results, we can see that clustering factors have little influences on the spiking regularity when the entire energy is fixed, which could be controlled by the averaged coupling strength and the averaged connection probability.

  13. Lamellar ichthyosis

    Science.gov (United States)

    ... the palms and soles is thickened Treatment Collodion babies usually need to stay in the neonatal intensive care unit (NICU). They are placed in a high-humidity incubator. They will need extra feedings. Moisturizers need to ...

  14. Two types of lamellar phase in TTAB/water/pentanol system as detected by positron lifetime spectroscopy

    International Nuclear Information System (INIS)

    Khani, P.H.; Yadav, R.; Singh, K.C.; Jain, P.C.

    2004-01-01

    Positron lifetime measurements were performed in TTAB(Tetradecyl trimethyl ammonium bromide)/water/pentanol ternary systems prepared by adding varying amounts of pentanol to different mother solutions of TTAB/water system having fixed TTAB concentrations. Besides delineating various phase boundaries as obtained by other conventional techniques, positron annihilation parameters were also found to be sensitive in detecting two kinds of lamellar structures in the otherwise considered to be a single liquid crystalline D phase of the system. The existence of such lamellar structures has been demonstrated by a change in the trend of o-Ps lifetime parameter when the system passes from one type of lamellar structure to the other type. The results of such a finding are presented in this paper. (orig.)

  15. Regular variation on measure chains

    Czech Academy of Sciences Publication Activity Database

    Řehák, Pavel; Vitovec, J.

    2010-01-01

    Roč. 72, č. 1 (2010), s. 439-448 ISSN 0362-546X R&D Projects: GA AV ČR KJB100190701 Institutional research plan: CEZ:AV0Z10190503 Keywords : regularly varying function * regularly varying sequence * measure chain * time scale * embedding theorem * representation theorem * second order dynamic equation * asymptotic properties Subject RIV: BA - General Mathematics Impact factor: 1.279, year: 2010 http://www.sciencedirect.com/science/article/pii/S0362546X09008475

  16. Manifold Regularized Correlation Object Tracking

    OpenAIRE

    Hu, Hongwei; Ma, Bo; Shen, Jianbing; Shao, Ling

    2017-01-01

    In this paper, we propose a manifold regularized correlation tracking method with augmented samples. To make better use of the unlabeled data and the manifold structure of the sample space, a manifold regularization-based correlation filter is introduced, which aims to assign similar labels to neighbor samples. Meanwhile, the regression model is learned by exploiting the block-circulant structure of matrices resulting from the augmented translated samples over multiple base samples cropped fr...

  17. On geodesics in low regularity

    Science.gov (United States)

    Sämann, Clemens; Steinbauer, Roland

    2018-02-01

    We consider geodesics in both Riemannian and Lorentzian manifolds with metrics of low regularity. We discuss existence of extremal curves for continuous metrics and present several old and new examples that highlight their subtle interrelation with solutions of the geodesic equations. Then we turn to the initial value problem for geodesics for locally Lipschitz continuous metrics and generalize recent results on existence, regularity and uniqueness of solutions in the sense of Filippov.

  18. Fumonisin B₁ (FB₁) Induces Lamellar Separation and Alters Sphingolipid Metabolism of In Vitro Cultured Hoof Explants.

    Science.gov (United States)

    Reisinger, Nicole; Dohnal, Ilse; Nagl, Veronika; Schaumberger, Simone; Schatzmayr, Gerd; Mayer, Elisabeth

    2016-03-24

    One of the most important hoof diseases is laminitis. Yet, the pathology of laminitis is not fully understood. Different bacterial toxins, e.g. endotoxins or exotoxins, seem to play an important role. Additionally, ingestion of mycotoxins, toxic secondary metabolites of fungi, might contribute to the onset of laminitis. In this respect, fumonsins are of special interest since horses are regarded as species most susceptible to this group of mycotoxins. The aim of our study was to investigate the influence of fumonisin B₁ (FB₁) on primary isolated epidermal and dermal hoof cells, as well as on the lamellar tissue integrity and sphingolipid metabolism of hoof explants in vitro. There was no effect of FB₁ at any concentration on dermal or epidermal cells. However, FB₁ significantly reduced the separation force of explants after 24 h of incubation. The Sa/So ratio was significantly increased in supernatants of explants incubated with FB₁ (2.5-10 µg/mL) after 24 h. Observed effects on Sa/So ratio were linked to significantly increased sphinganine concentrations. Our study showed that FB₁ impairs the sphingolipid metabolism of explants and reduces lamellar integrity at non-cytotoxic concentrations. FB₁ might, therefore, affect hoof health. Further in vitro and in vivo studies are necessary to elucidate the effects of FB₁ on the equine hoof in more detail.

  19. Epiretinal proliferation in lamellar macular holes and full-thickness macular holes: clinical and surgical findings.

    Science.gov (United States)

    Lai, Tso-Ting; Chen, San-Ni; Yang, Chung-May

    2016-04-01

    To report the clinical findings and surgical outcomes of lamellar macular holes (LMH) with or without lamellar hole-associated epiretinal proliferation (LHEP), and those of full-thickness macular holes (FTMH) presenting with LHEP. From 2009 to 2013, consecutive cases of surgically treated LMH, and all FTMH cases with LHEP were reviewed, given a follow-up time over 1 year. In the LMH group (43 cases), those with LHEP (19 cases) had significantly thinner bases and larger openings than those without (24 cases). The rate of disrupted IS/OS line was higher in the LHEP subgroup preoperatively (68.4 % vs 37.5 %), but similar between subgroups postoperatively (36.8 % and 33.3 %). The preoperative and postoperative visual acuity showed no significant difference between two subgroups. In the FTMH group (13 cases), the average hole size was 219.2 ± 92.1 μm. Permanent or transient spontaneous hole closure was noted in 69.2 % of cases. An intact IS-OS line was found in only 23 % of cases at the final follow-up. In the LMH group, LHEP was associated with a more severe defect but didn't affect surgical outcomes. In the FTMH group, spontaneous hole closure was frequently noted. Despite small holes, disruption of IS-OS line was common after hole closure.

  20. Sutureless intrascleral intraocular lens fixation with lamellar dissection of scleral tunnel

    Directory of Open Access Journals (Sweden)

    Kawaji T

    2016-01-01

    Full Text Available Takahiro Kawaji,1,2 Tomoki Sato,2 Hidenobu Tanihara11Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Chuo-ku, 2Sato Eye & Internal Medicine Clinic, Kumamoto, JapanPurpose: To report the results of sutureless scleral fixation of a posterior chamber intraocular lens (IOL by using our developed simple technique.Methods: We retrospectively reviewed the medical records of 48 eyes of 47 patients who underwent sutureless intrascleral IOL fixation by using our modified technique. A 25-gauge microvitreoretinal knife was used to perform sclerotomies and create limbus-parallel scleral tunnels with lamellar dissection in which the haptics were fixed.Results: The IOLs were fixed and centered well. The mean follow-up period was 26.7 months. Postoperative complications included smooth vitreous hemorrhage in four eyes (8.3%, cystoid macular edema in two eyes (4.2%, and iris capture of the IOL in two eyes (4.2%. No other complications, such as breakage of the IOL, spontaneous IOL dislocation, or retinal detachment, were detected during the follow-up period.Conclusion: The lamellar dissection of the limbus-parallel scleral tunnel can simplify the forceps-assisted introduction of the haptics into the scleral tunnel, and this technique seemed to be safe.Keywords: intraocular lenses, ophthalmologic surgical procedures, intrascleral fixation, sutureless fixation

  1. A novel ethanol templating synthesis of ordered lamellar superstructured crystalline zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chao, E-mail: liuchao_tj@yahoo.com; Wang Bin [Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology (China); Ji Xiujie, E-mail: jxjchem@yahoo.com [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University (China); Zhao Shanshan; Wu Jie; Jia Jianlong; Ma Dongxia [Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology (China)

    2012-03-15

    Soft template technique has attracted great interest, because it is a facile, inexpensive and efficient synthesis strategy for ordered superstructural systems. Here, a novel ethanol template was used to synthesize the ordered lamellar superstructured crystalline zirconia (L{alpha}-ZrO{sub 2}) without post-treatments and surfactants. ZrOCl{sub 2} and NaOH were served as Zr source and precipitant, respectively. XRD analysis showed that L{alpha}-ZrO{sub 2} is crystalline. XPS spectra indicated the physical adsorption of ethanol molecules in L{alpha}-ZrO{sub 2}. TEM further observed and proved the 1.36-nm period of superstructure detected and calculated by SAXRD (1.35 nm), which is composed of 0.68-nm thick ZrO{sub 2} and pore alternatively. In contrast, the template-free ZrO{sub 2} (TF-ZrO{sub 2}) presents no superstructure and is poorly crystallized. As a soft template, ethanol presents the roles of (i) inducing the growth of zirconia layers, (ii) directing the self-assembly of ordered lamellar superstructure, and (iii) decreasing the crystallization temperature. The possible mechanism of ethanol serving as a soft template was proposed and discussed in thermodynamics.

  2. A novel ethanol templating synthesis of ordered lamellar superstructured crystalline zirconia

    International Nuclear Information System (INIS)

    Liu Chao; Wang Bin; Ji Xiujie; Zhao Shanshan; Wu Jie; Jia Jianlong; Ma Dongxia

    2012-01-01

    Soft template technique has attracted great interest, because it is a facile, inexpensive and efficient synthesis strategy for ordered superstructural systems. Here, a novel ethanol template was used to synthesize the ordered lamellar superstructured crystalline zirconia (Lα-ZrO 2 ) without post-treatments and surfactants. ZrOCl 2 and NaOH were served as Zr source and precipitant, respectively. XRD analysis showed that Lα-ZrO 2 is crystalline. XPS spectra indicated the physical adsorption of ethanol molecules in Lα-ZrO 2 . TEM further observed and proved the 1.36-nm period of superstructure detected and calculated by SAXRD (1.35 nm), which is composed of 0.68-nm thick ZrO 2 and pore alternatively. In contrast, the template-free ZrO 2 (TF-ZrO 2 ) presents no superstructure and is poorly crystallized. As a soft template, ethanol presents the roles of (i) inducing the growth of zirconia layers, (ii) directing the self-assembly of ordered lamellar superstructure, and (iii) decreasing the crystallization temperature. The possible mechanism of ethanol serving as a soft template was proposed and discussed in thermodynamics.

  3. Nucleation of the lamellar phase from the disordered phase of the renormalized Landau-Brazovskii model

    Science.gov (United States)

    Carilli, Michael F.; Delaney, Kris T.; Fredrickson, Glenn H.

    2018-02-01

    Using the zero-temperature string method, we investigate nucleation of a stable lamellar phase from a metastable disordered phase of the renormalized Landau-Brazovskii model at parameters explicitly connected to those of an experimentally accessible diblock copolymer melt. We find anisotropic critical nuclei in qualitative agreement with previous experimental and analytic predictions; we also find good quantitative agreement with the predictions of a single-mode analysis. We conduct a thorough search for critical nuclei containing various predicted and experimentally observed defect structures. The predictions of the renormalized model are assessed by simulating the bare Landau-Brazovskii model with fluctuations. We find that the renormalized model makes reasonable predictions for several important quantities, including the order-disorder transition (ODT). However, the critical nucleus size depends sharply on proximity to the ODT, so even small errors in the ODT predicted by the renormalized model lead to large errors in the predicted critical nucleus size. We conclude that the renormalized model is a poor tool to study nucleation in the fluctuating Landau-Brazovskii model, and recommend that future studies work with the fluctuating bare model directly, using well-chosen collective variables to investigate kinetic pathways in the disorder → lamellar transition.

  4. Lamellar Microdomains of Block-Copolymer-Based Ionic Supramolecules Exhibiting a Hierarchical Self-Assembly

    DEFF Research Database (Denmark)

    Ayoubi, Mehran Asad; Almdal, Kristoffer; Zhu, Kaizheng

    2014-01-01

    (Cn; n = 8, 12, and 16) trimethylammonium counterions (i.e., side chains) at various ion (pair) fractions X [i.e., counterion/side-chain grafting density; X = number of alkyl counterions (i.e., side chains) per acidic group of the parent PMAA block] these L-b-AC ionic supramolecules exhibit...... a spherical-in-lamellar hierarchical self-assembly. For these systems, (1) the effective Flory-Huggins interaction parameter between L- and AC-blocks chi'(Cn/x) was extracted, and (2) analysis of the lamellar microdomains showed that when there is an increase in X, alkyl counterion (i.e., side chain) length l......Based on a parent diblock copolymer of poly(styrene)-b-poly(methacrylic acid), PS-b-PMAA, linear-b-amphiphilic comb (L-b-AC) ionic supramolecules [Soft Matter 2013, 9, 1540-1555] are synthesized in which the poly(methacrylate) backbone of the ionic supramolecular AC-block is neutralized by alkyl...

  5. Preparation and electrochemical properties of lamellar MnO{sub 2} for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jun; Wei, Tong [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Cheng, Jie [Research Institute of Chemical Defense, Beijing 100083 (China); Fan, Zhuangjun, E-mail: fanzhj666@163.com [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Zhang, Milin [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2010-02-15

    Lamellar birnessite-type MnO{sub 2} materials were prepared by changing the pH of the initial reaction system via hydrothermal synthesis. The interlayer spacing of MnO{sub 2} with a layered structure increased gradually when the initial pH value varied from 12.43 to 2.81, while the MnO{sub 2}, composed of {alpha}-MnO{sub 2} and {gamma}-MnO{sub 2}, had a rod-like structure at pH 0.63. Electrochemical studies indicated that the specific capacitance of birnessite-type MnO{sub 2} was much higher than that of rod-like MnO{sub 2} at high discharge current densities due to the lamellar structure with fast intercalation/deintercalation of protons and high utilization of MnO{sub 2}. The initial specific capacitance of MnO{sub 2} prepared at pH 2.81 was 242.1 F g{sup -1} at 2 mA cm{sup -2} in 2 mol L{sup -1} (NH{sub 4}){sub 2}SO{sub 4} aqueous electrolyte. The capacitance increased by about 8.1% of initial capacitance after 200 cycles at a current density of 100 mA cm{sup -2}.

  6. Electroclinic effect in the chiral lamellar α phase of a lyotropic liquid crystal

    Science.gov (United States)

    Harjung, Marc D.; Giesselmann, Frank

    2018-03-01

    In thermotropic chiral Sm -A* phases, an electric field along the smectic layers breaks the D∞ symmetry of the Sm -A* phase and induces a tilt of the liquid crystal director. This so-called electroclinic effect (ECE) was first reported by Garoff and Meyer in 1977 and attracted substantial scientific and technological interest due to its linear and submicrosecond electro-optic response [S. Garoff and R. B. Meyer, Phys. Rev. A 19, 338 (1979), 10.1103/PhysRevA.19.338]. We now report the observation of an ECE in the pretransitional regime from a lyotropic chiral lamellar Lα* phase into a lyo-Sm -C* phase, the lyotropic analog to the thermotropic Sm -C* phase which was recently discovered by Bruckner et al. [Angew. Chem. Int. Ed. 52, 8934 (2013), 10.1002/anie.201303344]. We further show that the observed ECE has all signatures of its thermotropic counterpart, namely (i) the effect is chiral in nature and vanishes in the racemic Lα phase, (ii) the effect is essentially linear in the sign and magnitude of the electric field, and (iii) the magnitude of the effect diverges hyperbolically as the temperature approaches the critical temperature of the second order tilting transition. Specific deviations between the ECEs in chiral lamellar and chiral smectic phases are related to the internal field screening effect of electric double layers formed by inevitable ionic impurities in lyotropic phases.

  7. Condition Number Regularized Covariance Estimation.

    Science.gov (United States)

    Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

    2013-06-01

    Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the "large p small n " setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required.

  8. Condition Number Regularized Covariance Estimation*

    Science.gov (United States)

    Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

    2012-01-01

    Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the “large p small n” setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required. PMID:23730197

  9. Growth crystallography and lamellar to rod transition in directionally solidified Nb--Nb2C eutectic composites

    International Nuclear Information System (INIS)

    David, S.A.; Santhanam, A.T.; Brody, H.D.

    1976-01-01

    The transition in morphology of the carbide phase is discussed in terms of the relative volume fraction of the phases, growth rate, and orientation relationships. The carbide morphology is influenced by the growth rate and carbon content. For constant growth rate increasing the volume fraction of the carbide phase favors the lamellar morphology. At low growth rates the lamellar morphology is favored, and at high growth rates the rod-like morphology is favored. Growth crystallography has no direct influence on the transition in carbide morphology

  10. Geometric continuum regularization of quantum field theory

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1989-01-01

    An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs

  11. Outstanding compressive creep strength in Cr/Ir-codoped (Mo0.85Nb0.15)Si2 crystals with the unique cross-lamellar microstructure.

    Science.gov (United States)

    Hagihara, Koji; Ikenishi, Takaaki; Araki, Haruka; Nakano, Takayoshi

    2017-06-21

    A (Mo 0.85 Nb 0.15 )Si 2 crystal with an oriented, lamellar, C40/C11 b two-phase microstructure is a promising ultrahigh-temperature (UHT) structural material, but its low room-temperature fracture toughness and low high-temperature strength prevent its practical application. As a possibility to overcome these problems, we first found a development of unique "cross-lamellar microstructure", by the cooping of Cr and Ir. The cross-lamellar microstructure consists of a rod-like C11 b -phase grains that extend along a direction perpendicular to the lamellar interface in addition to the C40/C11 b fine lamellae. In this study, the effectiveness of the cross-lamellar microstructure for improving the high-temperature creep deformation property, being the most essential for UHT materials, was examined by using the oriented crystals. The creep rate significantly reduced along a loading orientation parallel to the lamellar interface. Furthermore, the degradation in creep strength for other loading orientation that is not parallel to the lamellar interface, which has been a serious problem up to now, was also suppressed. The results demonstrated that the simultaneous improvement of high-temperature creep strength and room temperature fracture toughness can be first accomplished by the development of unique cross-lamellar microstructure, which opens a potential avenue for the development of novel UHT materials as alternatives to existing Ni-based superalloys.

  12. Metric regularity and subdifferential calculus

    International Nuclear Information System (INIS)

    Ioffe, A D

    2000-01-01

    The theory of metric regularity is an extension of two classical results: the Lyusternik tangent space theorem and the Graves surjection theorem. Developments in non-smooth analysis in the 1980s and 1990s paved the way for a number of far-reaching extensions of these results. It was also well understood that the phenomena behind the results are of metric origin, not connected with any linear structure. At the same time it became clear that some basic hypotheses of the subdifferential calculus are closely connected with the metric regularity of certain set-valued maps. The survey is devoted to the metric theory of metric regularity and its connection with subdifferential calculus in Banach spaces

  13. Manifold Regularized Correlation Object Tracking.

    Science.gov (United States)

    Hu, Hongwei; Ma, Bo; Shen, Jianbing; Shao, Ling

    2018-05-01

    In this paper, we propose a manifold regularized correlation tracking method with augmented samples. To make better use of the unlabeled data and the manifold structure of the sample space, a manifold regularization-based correlation filter is introduced, which aims to assign similar labels to neighbor samples. Meanwhile, the regression model is learned by exploiting the block-circulant structure of matrices resulting from the augmented translated samples over multiple base samples cropped from both target and nontarget regions. Thus, the final classifier in our method is trained with positive, negative, and unlabeled base samples, which is a semisupervised learning framework. A block optimization strategy is further introduced to learn a manifold regularization-based correlation filter for efficient online tracking. Experiments on two public tracking data sets demonstrate the superior performance of our tracker compared with the state-of-the-art tracking approaches.

  14. Queratitis lamelar difusa después del Lasik Diffuse lamellar keratitis after LASIK

    Directory of Open Access Journals (Sweden)

    Lorelei Ortega Díaz

    2010-12-01

    Full Text Available OBJETIVO: Describir el comportamiento de la queratitis lamelar difusa como complicación después de emplear la técnica quirúrgica queratomileusis in situ con láser. MÉTODOS: Se realizó un estudio descriptivo, de corte transversal en el Servicio de Cirugía Refractiva Corneal del Instituto Cubano de Oftalmología "Ramón Pando Ferrer" en el último trimestre del año 2008. La muestra quedó conformada por 16 ojos a los que se les realizó la queratomileusis in situ con láser como técnica quirúrgica para corregir ametropía y que presentaron complicaciones con esta cirugía. Se analizaron variables como la agudeza visual sin corrección; los ojos con esta complicación fueron analizados según la clasificación de Linebarger. RESULTADOS: La frecuencia de queratitis lamelar difusa fue de 3,0 por cada 100. La agudeza visual no corregida se comportó entre 0,8 y 1,0 en 12 ojos de 16 afectados, el estadio 1 se presentó en 12 ojos. CONCLUSIONES: La queratitis lamelar difusa es una complicación poco frecuente, los casos que la padecieron alcanzaron una buena agudeza visual final sin corrección. Predominó la forma leve de este cuadro.OBJECTIVE: To describe the situation of Diffuse lamellar keratitis as a complication after in situ keratomileusis with laser. METHODS: A descriptive cross-sectional study was carried out in the Refractive Corneal Service of "Ramón Pando Ferrer" Cuban Institute of Ophthalmology during the last quarter of 2008. The sample embraced 16 eyes that underwent in situ keratomileusis plus laser as the refractive procedure to correct ametropy and presented with some complications. Visual acuity without correction was one the analyzed variables and the eyes with this type of complication were classified according to Linebarger´s classification. RESULTS: The diffuse lamellar keratitis frequency was 3.0 per one hundred cases, the visual acuity without correction was 0.8 to 1.0 in 12 out of 16 eyes whereas stage 1 was

  15. Dimensional regularization in configuration space

    International Nuclear Information System (INIS)

    Bollini, C.G.; Giambiagi, J.J.

    1995-09-01

    Dimensional regularization is introduced in configuration space by Fourier transforming in D-dimensions the perturbative momentum space Green functions. For this transformation, Bochner theorem is used, no extra parameters, such as those of Feynman or Bogoliubov-Shirkov are needed for convolutions. The regularized causal functions in x-space have ν-dependent moderated singularities at the origin. They can be multiplied together and Fourier transformed (Bochner) without divergence problems. The usual ultraviolet divergences appear as poles of the resultant functions of ν. Several example are discussed. (author). 9 refs

  16. Regular algebra and finite machines

    CERN Document Server

    Conway, John Horton

    2012-01-01

    World-famous mathematician John H. Conway based this classic text on a 1966 course he taught at Cambridge University. Geared toward graduate students of mathematics, it will also prove a valuable guide to researchers and professional mathematicians.His topics cover Moore's theory of experiments, Kleene's theory of regular events and expressions, Kleene algebras, the differential calculus of events, factors and the factor matrix, and the theory of operators. Additional subjects include event classes and operator classes, some regulator algebras, context-free languages, communicative regular alg

  17. Matrix regularization of 4-manifolds

    OpenAIRE

    Trzetrzelewski, M.

    2012-01-01

    We consider products of two 2-manifolds such as S^2 x S^2, embedded in Euclidean space and show that the corresponding 4-volume preserving diffeomorphism algebra can be approximated by a tensor product SU(N)xSU(N) i.e. functions on a manifold are approximated by the Kronecker product of two SU(N) matrices. A regularization of the 4-sphere is also performed by constructing N^2 x N^2 matrix representations of the 4-algebra (and as a byproduct of the 3-algebra which makes the regularization of S...

  18. Retraction Note to: Ultra-High Strength and Ductile Lamellar-Structured Powder Metallurgy Binary Ti-Ta Alloys

    Science.gov (United States)

    Liu, Yong; Xu, Shenghang; Wang, Xin; Li, Kaiyang; Liu, Bin; Wu, Hong; Tang, Huiping

    2018-05-01

    The editors and authors have retracted the article, "Ultra-High Strength and Ductile Lamellar-Structured Powder Metallurgy Binary Ti-Ta Alloys" by Yong Liu, Shenghang Xu, Xin Wang, Kaiyang Li, Bin Liu, Hong Wu, and Huiping Tang (https://doi.org/10.1007/s11837-015-1801-1).

  19. Fatigue life analysis of unexpected failure in a lamellar TiAl alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.S.

    1999-07-01

    Unexpected catastrophic failure occurred in specimens of a lamellar TiAl alloy tested by axial fatigue. The failure initiated at locations away from artificial defects introduced to the specimens as crack starters. Fractographic examination of the fracture surface revealed the presence of featureless, low-energy facets that suggested the catastrophic crack may have initiated in one or more large grains that cleaved on a cleavage plane or an interface. A crack growth analysis of fatigue life of the test specimens suggested that the catastrophic crack propagated at stress intensity levels below the large crack threshold. Furthermore, the catastrophic crack propagated at rates that were higher than the average rates exhibited by small cracks, as well as by the large crack under equivalent stress intensity ranges. Because of this, the conventional life prediction approach based on the large crack growth data grossly overpredicted the fatigue life.

  20. Numerical simulation of transformation-induced microscopic residual stress in ferrite-martensite lamellar steel

    International Nuclear Information System (INIS)

    Mikami, Y; Inao, A; Mochizuki, M; Toyoda, M

    2009-01-01

    The effect of transformation-induced microscopic residual stress on fatigue crack propagation behavior of ferrite-martensite lamellar steel was discussed. Fatigue tests of prestrained and non-prestrained specimens were performed. Inflections and branches at ferrite-martensite boundaries were observed in the non-prestrained specimens. On the other hand, less inflections and branches were found in the prestrained specimens. The experimental results showed that the transformation induced microscopic residual stress has influence on the fatigue crack propagation behavior. To estimate the microscopic residual, a numerical simulation method for the calculation of microscopic residual stress stress induced by martensitic transformation was performed. The simulation showed that compressive residual stress was generated in martensite layer, and the result agree with the experimental result that inflections and branches were observed at ferrite-martensite boundaries.

  1. Neutron spin-echo investigation of the microemulsion dynamics. in bicontinuous lamellar and droplet phases

    CERN Document Server

    Mihailescu, M; Endo, H; Allgaier, J; Gompper, G; Stellbrink, J; Richter, D; Jakobs, B; Sottmann, T; Faragó, B

    2002-01-01

    Using neutron spin-echo (NSE) spectroscopy in combination with dynamic light scattering (DLS), we performed an extensive investigation of the bicontinuous phase in ternary water-surfactant-oil microemulsions, with extension to lamellar and droplet phases. The dynamical behavior of surfactant monolayers of decyl-polyglycol-ether (C sub 1 sub 0 E sub 4) molecules, or mixtures of surfactant with long amphiphilic block-copolymers of type poly-ethylene propylene/poly-ethylene oxide (PEP-PEO) was studied, under comparable conditions. The investigation techniques provide access to different length scales relative to the characteristic periodicity length of the microemulsion structure. Information on the elastic bending modulus is obtained from the local scale dynamics in view of existing theoretical descriptions and is found to be in accordance with small angle neutron scattering (SANS) studies. Evidence for the modified elastic properties and additional interaction of the amphiphilic layers due to the polymer is mo...

  2. CuInS[sub 2] with lamellar morphology; 1: Efficient photoanodes in acidic polyiodide medium

    Energy Technology Data Exchange (ETDEWEB)

    Cattarin, S. (Inst. di Polarografia ed Elettrochimica Preparativa del C.N.R., Padova (Italy)); Dietz, N.; Lewerenz, H.J. (Hahn-Meitner-Inst., Berlin (Germany))

    1994-05-01

    CuInS[sub 2] grown in a steep temperature gradient acquires a peculiar lamellar morphology, similar to that of layered compound semiconductors. Thin electrodes (of thickness down to 30 to 40 [mu]m) can be prepared by cleavage, reducing series resistance in the bulk of the semiconductor. The liquid junction of n-CuInS[sub 2] with acidic polyiodide medium 2M HI, 2.5 M CaI[sub 2], 40 mM I[sub 2] was investigated. The best photoanodes attained quantum yields of monochromatic light of about 0.7 and conversion efficiencies above 7% under simulated AM1 sunlight. Their performance does not decrease substantially under moderately concentrated sunlight (300 to 400 mW cm[sup [minus]2]), due to small ohmic losses. Cell output appears quite stable during the first week of operation, but irregular electrode corrosion is observed, which may be detrimental to long term operation.

  3. Pattern interpolation in thin films of lamellar, symmetric copolymers on nano-patterned substrates

    Science.gov (United States)

    Detcheverry, Francois; Nagpal, Umang; Liu, Guoliang; Nealey, Paul; de Pablo, Juan

    2009-03-01

    A molecular model of block copolymer systems is used to conduct a systematic study of the morphologies that arise when thin films of symmetric, lamellar forming block copolymer materials are deposited on nanopatterned surfaces. Over 500 distinct cases are considered. It is found that, in general, three distinct morphologies can arise depending on the strength of the substrate-polymer interactions, the film thickness, and the period of the substrate pattern. The relative stability of those morphologies is determined by direct calculation of the free energy differences. The dynamic propensity of those morphologies to emerge is examined by careful analysis of simulated trajectories. The results of this systematic study are used to interpret recent experimental data for films of polystyrene-PMMA copolymers on chemically nanopatterned surfaces.

  4. Instability of a Lamellar Phase under Shear Flow: Formation of Multilamellar Vesicles

    Science.gov (United States)

    Courbin, L.; Delville, J. P.; Rouch, J.; Panizza, P.

    2002-09-01

    The formation of closed-compact multilamellar vesicles (referred to in the literature as the ``onion texture'') obtained upon shearing lamellar phases is studied using small-angle light scattering and cross-polarized microscopy. By varying the shear rate γ ˙, the gap cell D, and the smectic distance d, we show that: (i)the formation of this structure occurs homogeneously in the cell at a well-defined wave vector qi, via a strain-controlled process, and (ii)the value of qi varies as (dγ ˙/D)1/3. These results strongly suggest that formation of multilamellar vesicles may be monitored by an undulation (buckling) instability of the membranes, as expected from theory.

  5. Formation of structural steady states in lamellar/sponge phase-separating fluids under shear flow

    Science.gov (United States)

    Panizza, P.; Courbin, L.; Cristobal, G.; Rouch, J.; Narayanan, T.

    2003-05-01

    We investigate the effect of shear flow on a lamellar-sponge phase-separating fluid when subjected to shear flow. We show the existence of two different steady states (droplets and ribbons structures) whose nature does not depend on the way to reach the two-phase unstable region of the phase diagram (temperature quench or stirring). The transition between ribbons and droplets is shear thickening and its nature strongly depends on what dynamical variable is imposed. If the stress is fixed, flow visualization shows the existence of shear bands at the transition, characteristic of coexistence in the cell between ribbons and droplets. In this shear-banding region, the viscosity oscillates. When the shear rate is fixed, no shear bands are observed. Instead, the transition exhibits a hysteretic behavior leading to a structural bi-stability of the phase-separating fluid under flow.

  6. The deformation twin in lamellar Ti 3Al/TiAl structure

    Science.gov (United States)

    Zhang, J. X.; Ye, H. Q.

    2003-04-01

    A Ti-48Al-2Cr (at.%) alloy consisting of γ+α 2 lamellar structure was deformed in compression at room temperature. Study by high resolution electron microscopy was carried out on the characteristic of induced γ T/α 2 interface. During deformation the γ T/α 2 interface presents a stepped structure and the γ/α 2 interface remains straight. The formation mechanism of γ T associated with misfit dislocations is proposed. 1/2[01 1¯] γ interfacial dislocation in the γ/α 2 interface can dissociate into a 1/6[ 1¯1 2¯] γ partial dislocation which glides on the ( 1¯11) γ plane and causes γ T to form.

  7. Fragmentation of α2 plates in a fully lamellar TiAl during creep

    International Nuclear Information System (INIS)

    Wang, J.G.; Hsiung, L.M.; Nieh, T.G.

    1999-01-01

    The fragmentation and spheroidization of α 2 laths in a fully-lamellar TiAl alloy during creep were examined. Three possible mechanisms, Rayleigh's perturbation model, subgrain boundary groove mechanism and intersection of deformation twins with α 2 lamellae were presented and discussed. During creep deformation, the pile-up of interfacial dislocations leads to a change of planar interface, which, in turn, causes a difference in local chemical potential, and further results in the spheroidization of α 2 lamellae. On the other hand, the deformation of the α 2 phase is expected to be induced by the high local stress concentration introduced by the pile up of interfacial dislocations. The dynamic recovery process may lead to the formation of subgrain boundaries in the α 2 lamellae, which results in the spheroidization and termination of α 2 lamellae with the aid of diffusion during creep

  8. Nucleation of the lamellar decomposition in a Ti-44Al-4Nb-4Zr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.C.; Cheng, T.T.; Aindow, M

    2004-01-05

    The onset of the lamellar decomposition ({alpha}{yields}{alpha}{sub 2}+{gamma}) in a titanium aluminide alloy containing Nb and Zr has been studied by transmission electron microscopy. Samples water-quenched from the solution-treatment temperature of 1350 deg. C show fault-like features resembling those reported previously as the precursors for the formation of the {gamma} lamellae. High-resolution lattice images obtained from such features have revealed that the 'faults' are actually embryonic {gamma} lamellae, just a few atomic layers in thickness, which clearly exhibit the ordered L1{sub 0} structure. This implies that the {gamma} phase is formed directly, rather than via some intermediate disordered face-centred-cubic phase as suggested previously. Moreover, the character and configuration of the interfacial defects is consistent with this occurring in a diffusive-displacive manner with short-range fluxes across the risers of mobile perfect interfacial disconnections.

  9. Nucleation of the lamellar decomposition in a Ti-44Al-4Nb-4Zr alloy

    International Nuclear Information System (INIS)

    Zhang, L.C.; Cheng, T.T.; Aindow, M.

    2004-01-01

    The onset of the lamellar decomposition (α→α 2 +γ) in a titanium aluminide alloy containing Nb and Zr has been studied by transmission electron microscopy. Samples water-quenched from the solution-treatment temperature of 1350 deg. C show fault-like features resembling those reported previously as the precursors for the formation of the γ lamellae. High-resolution lattice images obtained from such features have revealed that the 'faults' are actually embryonic γ lamellae, just a few atomic layers in thickness, which clearly exhibit the ordered L1 0 structure. This implies that the γ phase is formed directly, rather than via some intermediate disordered face-centred-cubic phase as suggested previously. Moreover, the character and configuration of the interfacial defects is consistent with this occurring in a diffusive-displacive manner with short-range fluxes across the risers of mobile perfect interfacial disconnections

  10. Early byzantine lamellar armour from Carthago Spartaria (Cartagena, Spain

    Directory of Open Access Journals (Sweden)

    Vizcaíno Sánchez, Jaime

    2008-12-01

    Full Text Available This article presents an Early Byzantine lamellar armour, retrieved in the excavations at the quarter built over the Roman Theatre of Cartagena. The armour has close parallels with contemporary known material from the central and eastern Mediterranean or other sites, and it is an important find which increases the body of archeological evidence about Byzantine presence in Spania.

    Este artículo presenta una coraza laminar protobizantina hallada en las excavaciones del barrio construido sobre el teatro romano de Cartagena. La coraza tiene estrechos paralelos con materiales contemporáneos del Mediterráneo Central y Oriental u otros lugares, y es un importante hallazgo que incrementa la nómina de evidencias arqueológicas acerca de la presencia bizantina en Spania.

  11. Stress relaxation experiments on a lamellar polystyrene-polyisoprene diblock copolymer melt

    DEFF Research Database (Denmark)

    Holmqvist, P.; Castelletto, V.; Hamley, I.W.

    2001-01-01

    The non-linear rheology of the lamellar phase of a polystyrene-polyisoprene diblock copolymer is studied by oscillatory shear experiments. The relaxation of the shear modulus, G(t, gamma) is studied as a function of strain amplitude, gamma, up to large amplitude strains, gamma = 100%. The decay...... of G(t, gamma) is analysed using the model-independent CONTIN inverse Laplace transform algorithm to obtain a series of relaxation times, which reveals multiple relaxation processes. The timescale for the fastest relaxation processes is compared to those previously observed for diblock copolymer melts...... via dynamic light scattering experiments. The slowest relaxation process may be related to the shear-induced orientation of the lamellae. It is shown that time-strain separability G(t, gamma)= G(t)h(gamma) can be applied, and the damping function h(gamma) is consistent with a strongly strain...

  12. The structure of a lipid-water lamellar phase containing two types of lipid monolayers

    International Nuclear Information System (INIS)

    Ranck, J.L.; Luzzati, V.; Zaccai, G.

    1980-01-01

    One lamellar phase, observed in the mitochondrial lipids-water system at low temperature (ca 253 K) and at low water content (ca 15%), contains four lipid monolayers in its unit cell, two of type α and two of type β. Previous X-ray scattering studies of this phase led to an ambiguity: the phase could contain either two homogeneous bilayers, one α and one β, or two mixed bilayers, each formed by an α and a β monolayer. A solution to this problem was sought in a neutron scattering study as a function of the D 2 O/H 2 O ratio. Because of limited resolution, straightforward analysis of the neutron scattering data leads also to ambiguous results. Using a more sophisticated analysis based upon the zeroth- and second-order moments of the Patterson peaks relevant to the exchangeable components, it is shown that the weight of the evidence is in favour of a structure containing mixed bilayers. (Auth.)

  13. Multipulse NMR study of the lamellar mesophase of some liquid crystals

    International Nuclear Information System (INIS)

    Jasinski, A.; Morris, P.G.; Mansfield, P.

    1977-01-01

    Multipulse NMR techniques have been used to investigate the dynamic jproperties of cesium perfluoro-octanoate (CsPFO) and ammonium perfluoro-octanoate (APFO) + water systems, which are liquid crystals, over a wide range of temperautre and concentration. Axially symmetric fluorine chemical shift tensors have been measured for the CF 2 and CF 3 groups by performing a rotation study of an aligned sample (50% CsPFO : 50% D 2 O) at room temperature. The order parameter S in the lamellar mesophase of 72,2% CsPFO : 27,8% D 2 O and 70% APFO : 30% D 2 O has been obtained over as temperature range 20 0 C - 85 0 C by fitting the multipulse spectra. (author)

  14. Morphology and hot deformation of lamellar microstructures in zirconium and titanium alloys

    International Nuclear Information System (INIS)

    Vanderesse, N.

    2008-06-01

    This study aims at providing a precise description of the lamellar microstructures of two alloys, Zircaloy-4 and TA6V, and at characterizing their deformation at high temperature. New experimental techniques have been developed for these materials: instrumented Jominy end quench test, channel-die with mobile walls, X-ray microtomography. The main results underline the role of the alpha-GB phase formed at the prior beta grain boundaries on the variant selection in Zircaloy-4 and TA6-V. The three dimensional organization of the colonies in TA6V is also revealed for the first time and discussed in relationship with the formation of the microstructure. In hot compressed Zircaloy-4 several mechanisms of strain localization are observed. Twinning activity at 750 C, in particular, is clearly put into evidence. A classification of these heterogeneities is proposed and their influence on the recrystallization is discussed. (author)

  15. An ALC study of spin exchange of a muoniated cosurfactant in lamellar phase surfactant dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Dilger, H. [Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)]. E-mail: h.dilger@ipc.uni-stuttgart.de; Martyniak, A. [Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Scheuermann, R. [Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Vujosevic' , D. [Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Tucker, I.M. [Unilever Research and Development, Port Sunlight, Wirral, CH63 3JW (United Kingdom); McKenzie, I. [Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); Roduner, E. [Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

    2006-03-31

    The Avoided Level Crossing muon spin resonance (ALC-{mu}SR) technique has been used to measure the Heisenberg spin exchange rate between the Mu adducts of 2-phenylethanol (PEA) and Ni{sup 2+} in a concentrated lamellar phase dispersion composed of the dichain cationic surfactant 2,3-diheptadecyl ester ethoxypropyl-1,1,1-trimethylammonium chloride (DHTAC) and water. Ni{sup 2+} is only dissolved in the aqueous phase, therefore information about the local environment of the PEA can be extracted from the spin exchange rate. In the high-temperature (L{sub {alpha}}) phase the spin exchange is very slow, revealing that PEA preferentially resides in the headgroup regime of the surfactant. In the low-temperature (L{sub {beta}}) phase the spin exchange is diffusion controlled, because the PEA is expelled into the water region between the bilayers.

  16. An ALC study of spin exchange of a muoniated cosurfactant in lamellar phase surfactant dispersions

    International Nuclear Information System (INIS)

    Dilger, H.; Martyniak, A.; Scheuermann, R.; Vujosevic', D.; Tucker, I.M.; McKenzie, I.; Roduner, E.

    2006-01-01

    The Avoided Level Crossing muon spin resonance (ALC-μSR) technique has been used to measure the Heisenberg spin exchange rate between the Mu adducts of 2-phenylethanol (PEA) and Ni 2+ in a concentrated lamellar phase dispersion composed of the dichain cationic surfactant 2,3-diheptadecyl ester ethoxypropyl-1,1,1-trimethylammonium chloride (DHTAC) and water. Ni 2+ is only dissolved in the aqueous phase, therefore information about the local environment of the PEA can be extracted from the spin exchange rate. In the high-temperature (L α ) phase the spin exchange is very slow, revealing that PEA preferentially resides in the headgroup regime of the surfactant. In the low-temperature (L β ) phase the spin exchange is diffusion controlled, because the PEA is expelled into the water region between the bilayers

  17. Linear low density polyethylene (LLDPE) and lamellar zirconium phosphate (Zr P) composites: morphology and mechanical properties

    International Nuclear Information System (INIS)

    Silva, Daniela F.; Mandes, Luis C.; Lino, Adan S.

    2011-01-01

    Composites of linear low density polyethylene (LLDPE) and zirconium phosphate (ZrP) were prepared by extrusion in the molten state, containing 2 (w%) of the lamellar filler. The filler was previously synthesized by direct precipitation method and characterized. After processing, the composite and the pure virgin polymer were molded by compression in order to obtain films of 1 mm thick which were characterized by X-ray diffraction at high angle (WAXD), stress-strain mechanical analysis and scanning electron microscopy (SEM). The WAXD and SEM analysis showed that there was no intercalation of LLDPE in zirconium phosphate, possibly due to the fact that the layers do not have spacing enough to allow the intercalation of polymer chains in the galleries of the filler and thus allow the exfoliation. (author)

  18. Multiscale Simulations of Lamellar PS–PEO Block Copolymers Doped with LiPF6 Ions

    KAUST Repository

    Sethuraman, Vaidyanathan

    2017-06-02

    We report the results of atomistic simulations of the structural equilibrium properties of PS–PEO block copolymer (BCP) melt in the ordered lamellar phase doped with LiPF6 salt. A hybrid simulation strategy, consisting of steps of coarse-graining and inverse coarse-graining, was employed to equilibrate the melt at an atomistic resolution in the ordered phase. We characterize the structural distributions between different atoms/ions and compare the features arising in BCPs against the corresponding behavior in PEO homopolymers for different salt concentrations. In addition, the local structural distributions are characterized in the lamellar phase as a function of distance from the interface. The cation–anion radial distribution functions (RDF) display stronger coordination in the block copolymer melts at high salt concentrations, whereas the trends are reversed for low salt concentrations. Radial distribution functions isolated in the PEO and PS domains demonstrate that the stronger coordination seen in BCPs arises from the influence of both the higher fraction of ions segregated in the PS phase and the influence of interactions in the PS domain. Such a behavior also manifests in the cation–anion clusters, which show a larger fraction of free ions in the BCP. While the average number of free anions (cations) decreases with increasing salt concentration, higher order aggregates of LiPF6 increase with increasing salt concentration. Further, the cation–anion RDFs display spatial heterogeneity, with a stronger cation–anion binding in the interfacial region compared to bulk of the PEO domain.

  19. Ion transport mechanisms in lamellar phases of salt-doped PS–PEO block copolymer electrolytes

    KAUST Repository

    Sethuraman, Vaidyanathan

    2017-10-23

    We use a multiscale simulation strategy to elucidate, at an atomistic level, the mechanisms underlying ion transport in the lamellar phase of polystyrene–polyethylene oxide (PS–PEO) block copolymer (BCP) electrolytes doped with LiPF6 salts. Explicitly, we compare the results obtained for ion transport in the microphase separated block copolymer melts to those for salt-doped PEO homopolymer melts. In addition, we also present results for dynamics of the ions individually in the PEO and PS domains of the BCP melt, and locally as a function of the distance from the lamellar interfaces. When compared to the PEO homopolymer melt, ions were found to exhibit slower dynamics in both the block copolymer (overall) and in the PEO phase of the BCP melt. Such results are shown to arise from the effects of slower polymer segmental dynamics in the BCP melt and the coordination characteristics of the ions. Polymer backbone-ion residence times analyzed as a function of distance from the interface indicate that ions have a larger residence time near the interface compared to that near the bulk of lamella, and demonstrates the influence of the glassy PS blocks and microphase segregation on the ion transport properties. Ion transport mechanisms in BCP melts reveal that there exist five distinct mechanisms for ion transport along the backbone of the chain and exhibit qualitative differences from the behavior in homopolymer melts. We also present results as a function of salt concentration which show that the mean-squared displacements of the ions decrease with increasing salt concentration, and that the ion residence times near the polymer backbone increase with increasing salt concentration.

  20. Ion transport mechanisms in lamellar phases of salt-doped PS–PEO block copolymer electrolytes

    KAUST Repository

    Sethuraman, Vaidyanathan; Mogurampelly, Santosh; Ganesan, Venkat

    2017-01-01

    We use a multiscale simulation strategy to elucidate, at an atomistic level, the mechanisms underlying ion transport in the lamellar phase of polystyrene–polyethylene oxide (PS–PEO) block copolymer (BCP) electrolytes doped with LiPF6 salts. Explicitly, we compare the results obtained for ion transport in the microphase separated block copolymer melts to those for salt-doped PEO homopolymer melts. In addition, we also present results for dynamics of the ions individually in the PEO and PS domains of the BCP melt, and locally as a function of the distance from the lamellar interfaces. When compared to the PEO homopolymer melt, ions were found to exhibit slower dynamics in both the block copolymer (overall) and in the PEO phase of the BCP melt. Such results are shown to arise from the effects of slower polymer segmental dynamics in the BCP melt and the coordination characteristics of the ions. Polymer backbone-ion residence times analyzed as a function of distance from the interface indicate that ions have a larger residence time near the interface compared to that near the bulk of lamella, and demonstrates the influence of the glassy PS blocks and microphase segregation on the ion transport properties. Ion transport mechanisms in BCP melts reveal that there exist five distinct mechanisms for ion transport along the backbone of the chain and exhibit qualitative differences from the behavior in homopolymer melts. We also present results as a function of salt concentration which show that the mean-squared displacements of the ions decrease with increasing salt concentration, and that the ion residence times near the polymer backbone increase with increasing salt concentration.

  1. Regularization of Nonmonotone Variational Inequalities

    International Nuclear Information System (INIS)

    Konnov, Igor V.; Ali, M.S.S.; Mazurkevich, E.O.

    2006-01-01

    In this paper we extend the Tikhonov-Browder regularization scheme from monotone to rather a general class of nonmonotone multivalued variational inequalities. We show that their convergence conditions hold for some classes of perfectly and nonperfectly competitive economic equilibrium problems

  2. Lattice regularized chiral perturbation theory

    International Nuclear Information System (INIS)

    Borasoy, Bugra; Lewis, Randy; Ouimet, Pierre-Philippe A.

    2004-01-01

    Chiral perturbation theory can be defined and regularized on a spacetime lattice. A few motivations are discussed here, and an explicit lattice Lagrangian is reviewed. A particular aspect of the connection between lattice chiral perturbation theory and lattice QCD is explored through a study of the Wess-Zumino-Witten term

  3. 76 FR 3629 - Regular Meeting

    Science.gov (United States)

    2011-01-20

    ... Meeting SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held at the offices of the Farm... meeting of the Board will be open to the [[Page 3630

  4. Forcing absoluteness and regularity properties

    NARCIS (Netherlands)

    Ikegami, D.

    2010-01-01

    For a large natural class of forcing notions, we prove general equivalence theorems between forcing absoluteness statements, regularity properties, and transcendence properties over L and the core model K. We use our results to answer open questions from set theory of the reals.

  5. Globals of Completely Regular Monoids

    Institute of Scientific and Technical Information of China (English)

    Wu Qian-qian; Gan Ai-ping; Du Xian-kun

    2015-01-01

    An element of a semigroup S is called irreducible if it cannot be expressed as a product of two elements in S both distinct from itself. In this paper we show that the class C of all completely regular monoids with irreducible identity elements satisfies the strong isomorphism property and so it is globally determined.

  6. Fluid queues and regular variation

    NARCIS (Netherlands)

    Boxma, O.J.

    1996-01-01

    This paper considers a fluid queueing system, fed by N independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index ¿. We show that its fat tail gives rise to an even

  7. Fluid queues and regular variation

    NARCIS (Netherlands)

    O.J. Boxma (Onno)

    1996-01-01

    textabstractThis paper considers a fluid queueing system, fed by $N$ independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index $zeta$. We show that its fat tail

  8. Empirical laws, regularity and necessity

    NARCIS (Netherlands)

    Koningsveld, H.

    1973-01-01

    In this book I have tried to develop an analysis of the concept of an empirical law, an analysis that differs in many ways from the alternative analyse's found in contemporary literature dealing with the subject.

    1 am referring especially to two well-known views, viz. the regularity and

  9. Interval matrices: Regularity generates singularity

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Shary, S.P.

    2018-01-01

    Roč. 540, 1 March (2018), s. 149-159 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : interval matrix * regularity * singularity * P-matrix * absolute value equation * diagonally singilarizable matrix Subject RIV: BA - General Mathematics Impact factor: 0.973, year: 2016

  10. Regularization in Matrix Relevance Learning

    NARCIS (Netherlands)

    Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael

    A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can

  11. Regular and conformal regular cores for static and rotating solutions

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Aïnou, Mustapha

    2014-03-07

    Using a new metric for generating rotating solutions, we derive in a general fashion the solution of an imperfect fluid and that of its conformal homolog. We discuss the conditions that the stress–energy tensors and invariant scalars be regular. On classical physical grounds, it is stressed that conformal fluids used as cores for static or rotating solutions are exempt from any malicious behavior in that they are finite and defined everywhere.

  12. Regular and conformal regular cores for static and rotating solutions

    International Nuclear Information System (INIS)

    Azreg-Aïnou, Mustapha

    2014-01-01

    Using a new metric for generating rotating solutions, we derive in a general fashion the solution of an imperfect fluid and that of its conformal homolog. We discuss the conditions that the stress–energy tensors and invariant scalars be regular. On classical physical grounds, it is stressed that conformal fluids used as cores for static or rotating solutions are exempt from any malicious behavior in that they are finite and defined everywhere.

  13. Gravitationally coupled electroweak monopole

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.M., E-mail: ymcho7@konkuk.ac.kr [Administration Building 310-4, Konkuk University, Seoul 143-701 (Korea, Republic of); School of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Kimm, Kyoungtae [Faculty of Liberal Education, Seoul National University, Seoul 151-747 (Korea, Republic of); Yoon, J.H. [Department of Physics, College of Natural Sciences, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2016-10-10

    We present a family of gravitationally coupled electroweak monopole solutions in Einstein–Weinberg–Salam theory. Our result confirms the existence of globally regular gravitating electroweak monopole which changes to the magnetically charged black hole as the Higgs vacuum value approaches to the Planck scale. Moreover, our solutions could provide a more accurate description of the monopole stars and magnetically charged black holes.

  14. Energy functions for regularization algorithms

    Science.gov (United States)

    Delingette, H.; Hebert, M.; Ikeuchi, K.

    1991-01-01

    Regularization techniques are widely used for inverse problem solving in computer vision such as surface reconstruction, edge detection, or optical flow estimation. Energy functions used for regularization algorithms measure how smooth a curve or surface is, and to render acceptable solutions these energies must verify certain properties such as invariance with Euclidean transformations or invariance with parameterization. The notion of smoothness energy is extended here to the notion of a differential stabilizer, and it is shown that to void the systematic underestimation of undercurvature for planar curve fitting, it is necessary that circles be the curves of maximum smoothness. A set of stabilizers is proposed that meet this condition as well as invariance with rotation and parameterization.

  15. Physical model of dimensional regularization

    Energy Technology Data Exchange (ETDEWEB)

    Schonfeld, Jonathan F.

    2016-12-15

    We explicitly construct fractals of dimension 4-ε on which dimensional regularization approximates scalar-field-only quantum-field theory amplitudes. The construction does not require fractals to be Lorentz-invariant in any sense, and we argue that there probably is no Lorentz-invariant fractal of dimension greater than 2. We derive dimensional regularization's power-law screening first for fractals obtained by removing voids from 3-dimensional Euclidean space. The derivation applies techniques from elementary dielectric theory. Surprisingly, fractal geometry by itself does not guarantee the appropriate power-law behavior; boundary conditions at fractal voids also play an important role. We then extend the derivation to 4-dimensional Minkowski space. We comment on generalization to non-scalar fields, and speculate about implications for quantum gravity. (orig.)

  16. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-09-07

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  17. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yi; Zhao, Shiguang; Gao, Xin

    2014-01-01

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  18. Circuit complexity of regular languages

    Czech Academy of Sciences Publication Activity Database

    Koucký, Michal

    2009-01-01

    Roč. 45, č. 4 (2009), s. 865-879 ISSN 1432-4350 R&D Projects: GA ČR GP201/07/P276; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : regular languages * circuit complexity * upper and lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.726, year: 2009

  19. Fabrication and characterization of large size {sup 6}LiF/CaF{sub 2}:Eu eutectic composites with the ordered lamellar structure

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Noriaki [Tokuyama Corporation, 3-3-1 Shibuya, Shibuya-ku, Tokyo 150-8383 (Japan); Fukuda, Kentaro, E-mail: ken-fukuda@tokuyama.co.jp [Tokuyama Corporation, 3-3-1 Shibuya, Shibuya-ku, Tokyo 150-8383 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Suyama, Toshihisa [Tokuyama Corporation, 3-3-1 Shibuya, Shibuya-ku, Tokyo 150-8383 (Japan); Watanabe, Kenichi; Yamazaki, Atsushi [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2011-10-01

    As alternative candidates for the {sup 3}He neutron detectors, {sup 6}LiF/CaF{sub 2}:Eu eutectic composites were fabricated and their scintillation properties were evaluated. Large size LiF/CaF{sub 2}:Eu eutectic composites of 58 mm diameter and 50 mm thickness were produced by Bridgman method. The composites had a finely ordered lamellar structure along the solidification direction. The lamellar structure was controlled by the direction and the rate of solidification, and it was optimized to improve the scintillation properties. Better results were achieved when thinner lamellar layers were aligned along the scintillation light path.

  20. Fabrication and characterization of large size 6LiF/CaF2:Eu eutectic composites with the ordered lamellar structure

    International Nuclear Information System (INIS)

    Kawaguchi, Noriaki; Fukuda, Kentaro; Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Suyama, Toshihisa; Watanabe, Kenichi; Yamazaki, Atsushi; Yoshikawa, Akira

    2011-01-01

    As alternative candidates for the 3 He neutron detectors, 6 LiF/CaF 2 :Eu eutectic composites were fabricated and their scintillation properties were evaluated. Large size LiF/CaF 2 :Eu eutectic composites of 58 mm diameter and 50 mm thickness were produced by Bridgman method. The composites had a finely ordered lamellar structure along the solidification direction. The lamellar structure was controlled by the direction and the rate of solidification, and it was optimized to improve the scintillation properties. Better results were achieved when thinner lamellar layers were aligned along the scintillation light path.

  1. Quantum implications of a scale invariant regularization

    Science.gov (United States)

    Ghilencea, D. M.

    2018-04-01

    We study scale invariance at the quantum level in a perturbative approach. For a scale-invariant classical theory, the scalar potential is computed at a three-loop level while keeping manifest this symmetry. Spontaneous scale symmetry breaking is transmitted at a quantum level to the visible sector (of ϕ ) by the associated Goldstone mode (dilaton σ ), which enables a scale-invariant regularization and whose vacuum expectation value ⟨σ ⟩ generates the subtraction scale (μ ). While the hidden (σ ) and visible sector (ϕ ) are classically decoupled in d =4 due to an enhanced Poincaré symmetry, they interact through (a series of) evanescent couplings ∝ɛ , dictated by the scale invariance of the action in d =4 -2 ɛ . At the quantum level, these couplings generate new corrections to the potential, as scale-invariant nonpolynomial effective operators ϕ2 n +4/σ2 n. These are comparable in size to "standard" loop corrections and are important for values of ϕ close to ⟨σ ⟩. For n =1 , 2, the beta functions of their coefficient are computed at three loops. In the IR limit, dilaton fluctuations decouple, the effective operators are suppressed by large ⟨σ ⟩, and the effective potential becomes that of a renormalizable theory with explicit scale symmetry breaking by the DR scheme (of μ =constant).

  2. General inverse problems for regular variation

    DEFF Research Database (Denmark)

    Damek, Ewa; Mikosch, Thomas Valentin; Rosinski, Jan

    2014-01-01

    Regular variation of distributional tails is known to be preserved by various linear transformations of some random structures. An inverse problem for regular variation aims at understanding whether the regular variation of a transformed random object is caused by regular variation of components ...

  3. Lamellar-crossing-structured Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposite for electrochemical supercapacitor materials

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingnan [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Wen, Ming, E-mail: m_wen@tongji.edu.cn [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092 (China); Chen, Shipei [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Wu, Qingsheng [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092 (China)

    2015-10-15

    Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructure with a single lamellar spacing of ∼5 nm was effectively constructed through two-phase-interface reaction process followed by the CNTs crossed among the lamellar-nanostructured Ni(OH){sub 2}. The resultant nanocomposite can offer large active surface areas and short diffusion paths for electrons and ions, and is investigated as a potential pseudocapacitor electrode material for electrochemical energy storage applications. Electrochemical data demonstrate that the as-prepared nanocomposite exhibits a high specific capacitance of ∼1600 F g{sup −1} at the scan rate of 1 mV s{sup −1} in 6 M KOH solution at normal pressure and temperature, which is great higher than Ni(OH){sub 2} (∼1200 F g{sup −1}). Furthermore, Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposite shows a higher energy density (∼125 Wh kg{sup −1}, 2 A g{sup −1}) and has a slightly decrease of 5% in specific capacitance after 1000 continuous charge/discharge cycles. - Graphical abstract: As-constructed Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructure exhibits remarkable enhancement in electrochemical stability and high specific capacity of ∼1600 F g{sup −1} at a scan rate of 1 mV s{sup −1}, suggesting promising potential for supercapacitor applications. - Highlights: • New designed lamellar-crossing-structured Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites have been firstly reported in this work. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructures show firm nanostructure and excellent electrochemical stability. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites exhibit excellent specific capacitance. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites have the potential application in electrochemical energy storage applications.

  4. The estimate of permittivity of anisotropic composites with lamellar inclusions by the self-assessment method

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2015-01-01

    Full Text Available Composites are widely used as structural or thermal protection materials; they are used as well as functional materials in a large number of different electrical devices and as dielectrics. This composite has one of the most important characteristics the relative permittivity. It depends primarily on the dielectric properties of the inclusions and the matrix as well as the shape and volume content of the inclusions.In this paper, a mathematical model of the interaction of the electrostatic fields in an isotropic plate and in the surrounding homogeneous anisotropic medium is constructed. This model describes the dielectric properties of the composite with such inclusions. A variant of the same orientation of lamellar inclusions is considered, which leads to the special case of anisotropy of the dielectric properties of the composite that has transverse isotropy towards the direction perpendicular to the inclusions. The shape of inclusions is represented as an oblate ellipsoid of revolution (spheroid. Transformation of the differential equation describing the distribution of the electric potential transversely to isotropic medium surrounding the spheroidal inclusion, to the Laplace equation with the subsequent transition from the initial spheroid to the given ellipsoid of rotation allows us to apply the self-assessment method for the determination of the dielectric properties of the composite. This method equates the result of averaging the perturbation of the electrostatic field in the inclusions and the matrix particles towards the unperturbed fields in the environment to zero.The constructed mathematical model allows us to determine the electrostatic field disturbance in the inclusions and the matrix particles towards the unperturbed field given in the environment at a distance from the inclusions and the matrix particles, much larger than their characteristic dimensions. By averaging the perturbation of the electrostatic field in all the

  5. New applications of Boson's coherent states of double modes at regular product

    International Nuclear Information System (INIS)

    Zhang Yongde; Ren Yong

    1987-05-01

    This paper presents a series of new applications of boson's coherent states of double modes by means of the technique of regular products. They include non-coupled double oscillator solutions at two time dependent extra-sources; coupled double oscillator solutions at two time dependent extra-sources; some applications to regular momentum theory; an explicit expression for time-reversal operator. (author). 7 refs

  6. Regularized Statistical Analysis of Anatomy

    DEFF Research Database (Denmark)

    Sjöstrand, Karl

    2007-01-01

    This thesis presents the application and development of regularized methods for the statistical analysis of anatomical structures. Focus is on structure-function relationships in the human brain, such as the connection between early onset of Alzheimer’s disease and shape changes of the corpus...... and mind. Statistics represents a quintessential part of such investigations as they are preluded by a clinical hypothesis that must be verified based on observed data. The massive amounts of image data produced in each examination pose an important and interesting statistical challenge...... efficient algorithms which make the analysis of large data sets feasible, and gives examples of applications....

  7. Regularization methods in Banach spaces

    CERN Document Server

    Schuster, Thomas; Hofmann, Bernd; Kazimierski, Kamil S

    2012-01-01

    Regularization methods aimed at finding stable approximate solutions are a necessary tool to tackle inverse and ill-posed problems. Usually the mathematical model of an inverse problem consists of an operator equation of the first kind and often the associated forward operator acts between Hilbert spaces. However, for numerous problems the reasons for using a Hilbert space setting seem to be based rather on conventions than on an approprimate and realistic model choice, so often a Banach space setting would be closer to reality. Furthermore, sparsity constraints using general Lp-norms or the B

  8. Academic Training Lecture - Regular Programme

    CERN Multimedia

    PH Department

    2011-01-01

    Regular Lecture Programme 9 May 2011 ACT Lectures on Detectors - Inner Tracking Detectors by Pippa Wells (CERN) 10 May 2011 ACT Lectures on Detectors - Calorimeters (2/5) by Philippe Bloch (CERN) 11 May 2011 ACT Lectures on Detectors - Muon systems (3/5) by Kerstin Hoepfner (RWTH Aachen) 12 May 2011 ACT Lectures on Detectors - Particle Identification and Forward Detectors by Peter Krizan (University of Ljubljana and J. Stefan Institute, Ljubljana, Slovenia) 13 May 2011 ACT Lectures on Detectors - Trigger and Data Acquisition (5/5) by Dr. Brian Petersen (CERN) from 11:00 to 12:00 at CERN ( Bldg. 222-R-001 - Filtration Plant )

  9. Manifestly scale-invariant regularization and quantum effective operators

    CERN Document Server

    Ghilencea, D.M.

    2016-01-01

    Scale invariant theories are often used to address the hierarchy problem, however the regularization of their quantum corrections introduces a dimensionful coupling (dimensional regularization) or scale (Pauli-Villars, etc) which break this symmetry explicitly. We show how to avoid this problem and study the implications of a manifestly scale invariant regularization in (classical) scale invariant theories. We use a dilaton-dependent subtraction function $\\mu(\\sigma)$ which after spontaneous breaking of scale symmetry generates the usual DR subtraction scale $\\mu(\\langle\\sigma\\rangle)$. One consequence is that "evanescent" interactions generated by scale invariance of the action in $d=4-2\\epsilon$ (but vanishing in $d=4$), give rise to new, finite quantum corrections. We find a (finite) correction $\\Delta U(\\phi,\\sigma)$ to the one-loop scalar potential for $\\phi$ and $\\sigma$, beyond the Coleman-Weinberg term. $\\Delta U$ is due to an evanescent correction ($\\propto\\epsilon$) to the field-dependent masses (of...

  10. Targeted inactivation of the murine Abca3 gene leads to respiratory failure in newborns with defective lamellar bodies

    International Nuclear Information System (INIS)

    Hammel, Markus; Michel, Geert; Hoefer, Christina; Klaften, Matthias; Mueller-Hoecker, Josef; Angelis, Martin Hrabe de; Holzinger, Andreas

    2007-01-01

    Mutations in the human ABCA3 gene, encoding an ABC-transporter, are associated with respiratory failure in newborns and pediatric interstitial lung disease. In order to study disease mechanisms, a transgenic mouse model with a disrupted Abca3 gene was generated by targeting embryonic stem cells. While heterozygous animals developed normally and were fertile, individuals homozygous for the altered allele (Abca3-/-) died within one hour after birth from respiratory failure, ABCA3 protein being undetectable. Abca3-/- newborns showed atelectasis of the lung in comparison to a normal gas content in unaffected or heterozygous littermates. Electron microscopy demonstrated the absence of normal lamellar bodies in type II pneumocytes. Instead, condensed structures with apparent absence of lipid content were found. We conclude that ABCA3 is required for the formation of lamellar bodies and lung surfactant function. The phenotype of respiratory failure immediately after birth corresponds to the clinical course of severe ABCA3 mutations in human newborns

  11. The Evolution of Splint Armour in Georgia and Byzantium: Lamellar and Scale Armour in the 10th-12th Centuries

    Directory of Open Access Journals (Sweden)

    Mamuka TSURTSUMIA

    2011-10-01

    Full Text Available Byzantine technology was part of the military technology that existed in vast areas of Eurasia; hence study of the armament of its neighbours is important.The purpose of the present paper is to add new data about Byzantium’s Caucasian neighbour (namely, Georgia. Besides that, it also includes certain views about the stages of the evolution and provenance of splint (scale and lamellar armour. This paper also attempts to clarify the difference between banded and linear suits of lamellar armour.There is no doubt that the Byzantine military machine exercised considerable influence on its neighbours, though an opposite phenomenon can also be noticed. The article shows that changes in armour were taking place almost simultaneously in the Byzantine Empire and the Georgian kingdoms and that some of the types of armour that were widespread in Byzantium may have originated in Georgia.

  12. Intense luminescence emission from rare-earth-doped MoO3 nanoplates and lamellar crystals for optoelectronic applications

    International Nuclear Information System (INIS)

    Vila, M; Díaz-Guerra, C; Jerez, D; Piqueras, J; Lorenz, K; Alves, E

    2014-01-01

    Strong and stable room-temperature photoluminescence (PL) emission is achieved in MoO 3 nanoplates and lamellar crystals doped with Er and Eu by ion implantation and subsequent annealing. Micro-Raman and PL spectroscopy reveal that optical activation of the rare earth ions and recovery of the original MoO 3 structure are achieved for shorter annealing treatments and for lower temperatures in nanoplates, as compared with lamellar crystals. Er seems to be more readily incorporated into optically active sites in the oxide lattice than Eu. The influence of the dimensionality of the host sample on the characteristics of the PL emission of both rare earth dopants is addressed. (paper)

  13. Clinical observation of corneal lamellar debridement combined with sutureless amniotic membrane transplantation for the treatment of superficial fungal keratitis

    Directory of Open Access Journals (Sweden)

    Huang Zhang

    2014-09-01

    Full Text Available AIM:To evaluate the clinical efficacy of corneal lamellar debridement combined with sutureless amniotic membrane transplantation for the treatment of superficial fungal keratitis.METHODS:Totally 22 cases(22 eyeswith superficial fungal keratitis were referred to our hospital from April 2012 to October 2013. The patients with persistent cornea ulcer after treatment of local and systemic antifungal drugs underwent corneal lamellar debridement combined with sutureless amniotic membrane transplantation, and the recipient bed was covered with an amniotic membrane using fibrin sealant during the operation. All patients were still given topical antifungal therapy for 1-2mo after operation. The followed-up time was 3mo or above. We observed the corneal healing and amniotic membrane adhesion by split lamp microscope, and investigated the transformation of amniotic membrane and fungal infection recurrence with confocal microscope. RESULTS: Corneal edema and anterior chamber reaction of 21 patients disappeared gradually, and no amniotic membrane graft dissolved and shed off within 1-2wk postoperatively. Two weeks after operation, the graft integrated into the corneal and the corneal wounds' thickness increased gradually, the corneal epithelium reconstructed and corneas became clear. Four weeks after operation, the corneal scarring developed gradually and fluorescence staining was negative. Nineteen cases' amniotic membranes that adhered with the cornea dissolved 4wk after operation. There were different degrees of corneal nebula or macula remained 3mo postoperatively. All patients' vision improved in varying degrees, except in 1 case with fungal keratitis who had been cured by lamellar keratoplasty.CONCLUSION:Corneal lamellar debridement combined with sutureless amniotic membrane transplantation can effectively remove the foci of inflammation, improve the local efficacy, shorten the operation time, relieve the postoperative reaction, and promote cornea

  14. RES: Regularized Stochastic BFGS Algorithm

    Science.gov (United States)

    Mokhtari, Aryan; Ribeiro, Alejandro

    2014-12-01

    RES, a regularized stochastic version of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton method is proposed to solve convex optimization problems with stochastic objectives. The use of stochastic gradient descent algorithms is widespread, but the number of iterations required to approximate optimal arguments can be prohibitive in high dimensional problems. Application of second order methods, on the other hand, is impracticable because computation of objective function Hessian inverses incurs excessive computational cost. BFGS modifies gradient descent by introducing a Hessian approximation matrix computed from finite gradient differences. RES utilizes stochastic gradients in lieu of deterministic gradients for both, the determination of descent directions and the approximation of the objective function's curvature. Since stochastic gradients can be computed at manageable computational cost RES is realizable and retains the convergence rate advantages of its deterministic counterparts. Convergence results show that lower and upper bounds on the Hessian egeinvalues of the sample functions are sufficient to guarantee convergence to optimal arguments. Numerical experiments showcase reductions in convergence time relative to stochastic gradient descent algorithms and non-regularized stochastic versions of BFGS. An application of RES to the implementation of support vector machines is developed.

  15. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  16. Bilateral diffuse lamellar keratitis triggered by permanent eyeliner tattoo treatment: A case report.

    Science.gov (United States)

    Lu, Cheng-Wei; Liu, Xiu-Fen; Zhou, Dan-Dan; Kong, Yu-Jiao; Qi, Xiao-Feng; Liu, Tao-Tao; Qu, Ting; Pan, Xiao-Tao; Liu, Cong; Hao, Ji-Long

    2017-07-01

    Diffuse lamellar keratitis (DLK) is a sterile inflammation of the cornea, which may occur after laser-assisted in situ keratomileusis (LASIK) surgery. Little is known about the association of DLK with permanent eyeliner tattoo. The present case report describes the case of a 37-year-old Chinese woman who developed severe foreign body sensation in both eyes 1 week after receiving bilateral permanent eyeliner tattoo treatment. The patient had received bilateral LASIK surgery 10 years previously. Slit-lamp biomicroscopy revealed diffused granular infiltrates precipitated around the edge of the corneal flaps in both eyes. After topical treatment, DLK persisted. Therefore, the patient underwent surgery to remove the corneal epithelium around the DLK lesion. There was no recurrence of the disease during the 3-month observation period. To our knowledge, this is the first case report describing a case of late-onset of DLK that was triggered by permanent eyeliner tattoo. Doctors should be aware of the diagnosis and treatment of this complication associated with the application of permanent eyeliner tattoo as the popularity of this cosmetic procedure increases.

  17. Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

    Science.gov (United States)

    Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

    2015-03-01

    Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time care.

  18. Analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, Romain [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France); Centre Nationale de la Recherche Scientifique (CNRS), Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes (France); Fourre, Yoann; Furet, Eric; Gautier, Regis; Le Fur, Eric [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France)

    2015-04-15

    An approach is presented that enables the analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates. A comparison of previously reported vanadium phosphates reveals two modes of intercalation: (i) 3d transition metal ions intercalated between VOPO{sub 4} layers and (ii) alkali/alkaline earth metal ions between VOPO{sub 4}.H{sub 2}O layers. Both intercalations were investigated using DFT calculations in order to understand the relative shifts of the vanadium phosphate layers. These calculations in addition to an analysis of the stacking sequences in previously reported materials enable the prediction of the crystal structures of M{sub x}(VOPO{sub 4}).yH{sub 2}O (M = Cs{sup +}, Cd{sup 2+} and Sn{sup 2+}). Experimental realization and structural determination of Cd(VOPO{sub 4}){sub 2}.4H{sub 2}O by single-crystal X-ray diffraction confirmed the predicted stacking sequences. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Clinical study of the clusters of diffuse lamellar keratitis after laser corneal refractive surgery

    Directory of Open Access Journals (Sweden)

    Qing-Hong Lin

    2017-06-01

    Full Text Available AIM: To investigate the potential causes and management of the clusters of diffuse lamellar keratitis(DLKafter laser corneal refractive surgery. METHODS: The study enrolled 98 eyes(53 patientscomplicated with DLK after receiving laser in situ keratomileusis(LASIK, FS-LASIK or small-incision lenticule extraction(SMILEin our center from February 10th,2016 to February 22th,2016. They were given clinical classification treatments according to corneal layer inflammatory extent and then followed up after 1, 3, 5, 7, 10d and 1mo. RESULTS: The clusters of DLK occurred 5 times in the study period. The incidence and degree of DLK significantly decreased after changed the sterilization, surgical equipments, temperature and humidity of the operating room. There were 80 eyes(82%had stage 1 DLK, 11 eyes(11%had stage 2, 4 eyes(4%had stage 3 and 3 eyes(3%had stage 4. The incidence of DLK after FS-LASIK was 40%(79 eyes in 42 patients, that after LASIK assistant by Hastome keratome was 45%(10 eyes in 5 patients, that after SMILE was 20%(9 eyes in 6 patients. After intensive treatment, as glucocorticoid treatment and flap lifting flushing, all cases recovered within 1mo. CONCLUSION: The outbreak of DLK may be associated with the disposable item, flushing liquor, temperature and humidity of the operating room. Early diagnosis, prevention and treatment are the key of decreasing the incidence of DLK.

  20. Molecular Dynamics Study on Nucleation Behavior and Lamellar Mergence of Polyethylene Globule Crystallization

    Science.gov (United States)

    Yang, Xiaozhen; Wang, Simiao

    2012-02-01

    The site order parameter (SOP) has been adopted to analyze various order structure formation and distribution during the crystallization of a multi-chain polyethylene globule simulated by molecular dynamics. We found that the nucleation relies on crystallinity fluctuation with increase of amplitude, and the baby nucleus in the fluctuation suddenly appears with different shape and increasing size. In the growth stage, a number of lamellar mergence was observed and their selective behaviors were suggested to be related to the orientation difference between the merging lamellae. We obtained that SOP distribution of all atoms in the system during crystallization appears with two peaks: one for the amorphous phase and the other for the crystalline phase. Mesomorphic structures with medium orders locate between the two peaks as an order promotion pathway. Obtained data show that the medium order structure fluctuates at the growth front and does not always be available; the medium order structure existing at the front is not always good for developing. It is possibly caused by chain entanglement.

  1. Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing

    DEFF Research Database (Denmark)

    Sepe, Alessandro; Zhang, Jianqi; Perlich, Jan

    2016-01-01

    Solvent vapor annealing (SVA) is frequently used to improve the ordering in diblock copolymer thin films. An important question is which SVA protocol should be chosen to ensure thermodynamic equilibrium. Here, we investigate two thin films from a low molar-mass, lamellae-forming polystyrene....... SVA cycles were carried out with cyclohexane, and the structural changes were followed in-situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). Before and after SVA, Dlam,par is significantly lower than in the bulk, i.e. the equi-librium value of Dlam,par in thin film...... glassy again, affinely. During the second SVA cycle on the thin film, the scaling behavior of the lamellar thickness is identical to the one during the first drying and to the drying behavior of the thicker film. We conclude that one cycle of solvent vapor treatment with a degree of swelling of ca. 1...

  2. Investigation on the Effect of Sulfur and Titanium on the Microstructure of Lamellar Graphite Iron

    DEFF Research Database (Denmark)

    Moumeni, Elham; Stefanescu, Doru Michael; Tiedje, Niels Skat

    2013-01-01

    The goal of this work was to identify the inclusions in lamellar graphite cast iron in an effort to explain the nucleation of the phases of interest. Four samples of approximately the same carbon equivalent but different levels of sulfur and titanium were studied. The Ti/S ratios were from 0...... of complex Al, Ca, Mg oxide. An increased titanium level of 0.35 pct produced superfine interdendritic graphite (~10 μm) at low (0.012 wt pct) as well as at high-S contents. Ti also caused increased segregation in the microstructure of the analyzed irons and larger eutectic grains (cells). TiC did not appear...... to be a nucleation site for the primary austenite as it was found mostly at the periphery of the secondary arms of the austenite, in the last region to solidify. The effect of titanium in refining the graphite and increasing the austenite fraction can be explained through the widening of the liquidus...

  3. Investigation of Dendrite Coarsening in Complex Shaped Lamellar Graphite Iron Castings

    Directory of Open Access Journals (Sweden)

    Péter Svidró

    2017-07-01

    Full Text Available Shrinkage porosity and metal expansion penetration are two casting defects that appear frequently during the production of complex-shaped lamellar graphite iron components. These casting defects are formed during the solidification and usually form in the part of the casting which solidifies last. The position of the area that solidifies last is dependent on the thermal conditions. Test castings with thermal conditions like those existing in a complex-shaped casting were successfully applied to provoke a shrinkage porosity defect and a metal expansion penetration defect. The investigation of the primary dendrite morphology in the defected positions indicates a maximum intradendritic space, where the shrinkage porosity and metal expansion penetration defects appear. Moving away from the defect formation area, the intradendritic space decreases. A comparison of the intradendritic space with the simulated local solidification times indicates a strong relationship, which can be explained by the dynamic coarsening process. More specifically, long local solidification times facilitates the formation of a locally coarsened austenite morphology. This, in turn, enables the formation of a shrinkage porosity or a metal expansion penetration.

  4. Lamellar boundary alignment of DS-processed TiAl-W alloys by a solidification procedure

    Science.gov (United States)

    Jung, In-Soo; Oh, Myung-Hoon; Park, No-Jin; Kumar, K. Sharvan; Wee, Dang-Moon

    2007-12-01

    In this study, a β solidification procedure was used to align the lamellae in a Ti-47Al-2W (at.%) alloy parallel to the growth direction. The Bridgman technique and the floating zone process were used for directional solidification. The mechanical properties of the directionally solidified alloy were evaluated in tension at room temperature and at 800°C. At a growth rate of 30 mm/h (with the floating zone approach), the lamellae were well aligned parallel to the growth direction. The aligned lamellae yielded excellent room temperature tensile ductility. The tensile yield strength at 800°C was similar to that at room temperature. The orientation of the γ lamellar laths in the directionally solidified ingots, which were manufactured by means of a floating zone process, was identified with the aid of electron backscattered diffraction analysis. On the basis of this analysis, the preferred growth direction of the bcc-β dendrites that formed at high temperatures close to the melting point was inferred to be [001]β at a growth rate of 30 mm/h and [111]β at a growth rate of 90 mm/h.

  5. Hydrophobic nanoparticles promote lamellar to inverted hexagonal transition in phospholipid mesophases.

    Science.gov (United States)

    Bulpett, Jennifer M; Snow, Tim; Quignon, Benoit; Beddoes, Charlotte M; Tang, T-Y D; Mann, Stephen; Shebanova, Olga; Pizzey, Claire L; Terrill, Nicholas J; Davis, Sean A; Briscoe, Wuge H

    2015-12-07

    This study focuses on how the mesophase transition behaviour of the phospholipid dioleoyl phosphatidylethanolamine (DOPE) is altered by the presence of 10 nm hydrophobic and 14 nm hydrophilic silica nanoparticles (NPs) at different concentrations. The lamellar to inverted hexagonal phase transition (Lα-HII) of phospholipids is energetically analogous to the membrane fusion process, therefore understanding the Lα-HII transition with nanoparticulate additives is relevant to how membrane fusion may be affected by these additives, in this case the silica NPs. The overriding observation is that the HII/Lα boundaries in the DOPE p-T phase diagram were shifted by the presence of NPs: the hydrophobic NPs enlarged the HII phase region and thus encouraged the inverted hexagonal (HII) phase to occur at lower temperatures, whilst hydrophilic NPs appeared to stabilise the Lα phase region. This effect was also NP-concentration dependent, with a more pronounced effect for higher concentration of the hydrophobic NPs, but the trend was less clear cut for the hydrophilic NPs. There was no evidence that the NPs were intercalated into the mesophases, and as such it was likely that they might have undergone microphase separation and resided at the mesophase domain boundaries. Whilst the loci and exact roles of the NPs invite further investigation, we tentatively discuss these results in terms of both the surface chemistry of the NPs and the effect of their curvature on the elastic bending energy considerations during the mesophase transition.

  6. Formation of Lamellar Structured Oxide Dispersion Strengthening Layers in Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang-Il; Park, Jung-Hwan; Park, Dong-Jun; Kim, Hyun-Gil; Yang, Jae-Ho; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, Yoon-Soo [Hanbat National University, Daejeon (Korea, Republic of)

    2016-10-15

    Korea Atomic Energy Research Institute (KAERI) is one of the leading organizations for developing ATF claddings. One concept is to form an oxidation-resistant layer on Zr cladding surface. The other is to increase high-temperature mechanical strength of Zr tube. The oxide dispersion strengthened (ODS) zirconium was proposed to increase the strength of the Zr-based alloy up to high temperatures. According to our previous investigations, the tensile strength of Zircaloy-4 was increased by up to 20% with the formation of a thin dispersed oxide layer with a thickness less than 10% of that of the Zircaloy-4 substrate. However, the tensile elongation of the samples decreased drastically. The brittle fracture was a major concern in development of the ODS Zircaloy-4. In this study, a lamellar structure of ODS layer was formed to increase ductility of the ODS Zircaloy-4. The mechanical properties were varied depending on the structure of ODS layer. For example, the partial formation of ODS layer with the thickness of 10% to the substrate thickness induced the increase in tensile strength up to about 20% than fresh Zircaloy-4.

  7. Solid solutions of hydrogen uranyl phosphate and hydrogen uranyl arsenate. A family of luminescent, lamellar hosts

    International Nuclear Information System (INIS)

    Dorhout, P.K.; Rosenthal, G.L.; Ellis, A.B.

    1988-01-01

    Hydrogen uranyl phosphate, HUO 2 PO 4 x 4H 2 O (HUP), and hydrogen uranyl arsenate, HUO 2 AsO 4 x 4H 2 O (HUAs), form solid solutions of composition HUO 2 (PO 4 ) 1-x (AsO 4 )x (HUPAs), representing a family of lamellar, luminescent solids that can serve as hosts for intercalation chemistry. The solids are prepared by aqueous precipitation reactions from uranyl nitrate and mixtures of phosphoric and arsenic acids; thermogravimetric analysis indicates that the phases are tetrahydrates, like HUP and HUAs. Powder x-ray diffraction data reveal the HUPAs solids to be single phases whose lattice constants increase with X, in rough accord with Vegard's law Spectral shifts observed for the HUPAs samples. Emission from the solids is efficient (quantum yields of ∼ 0.2) and long-lived (lifetimes of ∼ 150 μs), although the measured values are uniformly smaller than those of HUP and HUAs; unimolecular radiative and nonradiative rate constants for excited-state decay of ∼ 1500 and 5000 s -1 , respectively, have been calculated for the compounds. 18 refs., 5 figs., 2 tabs

  8. From inactive to regular jogger

    DEFF Research Database (Denmark)

    Lund-Cramer, Pernille; Brinkmann Løite, Vibeke; Bredahl, Thomas Viskum Gjelstrup

    study was conducted using individual semi-structured interviews on how a successful long-term behavior change had been achieved. Ten informants were purposely selected from participants in the DANO-RUN research project (7 men, 3 women, average age 41.5). Interviews were performed on the basis of Theory...... of Planned Behavior (TPB) and The Transtheoretical Model (TTM). Coding and analysis of interviews were performed using NVivo 10 software. Results TPB: During the behavior change process, the intention to jogging shifted from a focus on weight loss and improved fitness to both physical health, psychological......Title From inactive to regular jogger - a qualitative study of achieved behavioral change among recreational joggers Authors Pernille Lund-Cramer & Vibeke Brinkmann Løite Purpose Despite extensive knowledge of barriers to physical activity, most interventions promoting physical activity have proven...

  9. Tessellating the Sphere with Regular Polygons

    Science.gov (United States)

    Soto-Johnson, Hortensia; Bechthold, Dawn

    2004-01-01

    Tessellations in the Euclidean plane and regular polygons that tessellate the sphere are reviewed. The regular polygons that can possibly tesellate the sphere are spherical triangles, squares and pentagons.

  10. On the equivalence of different regularization methods

    International Nuclear Information System (INIS)

    Brzezowski, S.

    1985-01-01

    The R-circunflex-operation preceded by the regularization procedure is discussed. Some arguments are given, according to which the results may depend on the method of regularization, introduced in order to avoid divergences in perturbation calculations. 10 refs. (author)

  11. The uniqueness of the regularization procedure

    International Nuclear Information System (INIS)

    Brzezowski, S.

    1981-01-01

    On the grounds of the BPHZ procedure, the criteria of correct regularization in perturbation calculations of QFT are given, together with the prescription for dividing the regularized formulas into the finite and infinite parts. (author)

  12. (2+1-dimensional regular black holes with nonlinear electrodynamics sources

    Directory of Open Access Journals (Sweden)

    Yun He

    2017-11-01

    Full Text Available On the basis of two requirements: the avoidance of the curvature singularity and the Maxwell theory as the weak field limit of the nonlinear electrodynamics, we find two restricted conditions on the metric function of (2+1-dimensional regular black hole in general relativity coupled with nonlinear electrodynamics sources. By the use of the two conditions, we obtain a general approach to construct (2+1-dimensional regular black holes. In this manner, we construct four (2+1-dimensional regular black holes as examples. We also study the thermodynamic properties of the regular black holes and verify the first law of black hole thermodynamics.

  13. Application of Turchin's method of statistical regularization

    Science.gov (United States)

    Zelenyi, Mikhail; Poliakova, Mariia; Nozik, Alexander; Khudyakov, Alexey

    2018-04-01

    During analysis of experimental data, one usually needs to restore a signal after it has been convoluted with some kind of apparatus function. According to Hadamard's definition this problem is ill-posed and requires regularization to provide sensible results. In this article we describe an implementation of the Turchin's method of statistical regularization based on the Bayesian approach to the regularization strategy.

  14. Regular extensions of some classes of grammars

    NARCIS (Netherlands)

    Nijholt, Antinus

    Culik and Cohen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this report we consider the analogous extension of the LL(k) grammers, called the LL-regular grammars. The relations of this class of grammars to other classes of grammars are shown. Every LL-regular

  15. Fishnet model for failure probability tail of nacre-like imbricated lamellar materials

    Science.gov (United States)

    Luo, Wen; Bažant, Zdeněk P.

    2017-12-01

    Nacre, the iridescent material of the shells of pearl oysters and abalone, consists mostly of aragonite (a form of CaCO3), a brittle constituent of relatively low strength (≈10 MPa). Yet it has astonishing mean tensile strength (≈150 MPa) and fracture energy (≈350 to 1,240 J/m2). The reasons have recently become well understood: (i) the nanoscale thickness (≈300 nm) of nacre's building blocks, the aragonite lamellae (or platelets), and (ii) the imbricated, or staggered, arrangement of these lamellea, bound by biopolymer layers only ≈25 nm thick, occupying engineering applications, however, the failure probability of ≤10-6 is generally required. To guarantee it, the type of probability density function (pdf) of strength, including its tail, must be determined. This objective, not pursued previously, is hardly achievable by experiments alone, since >10^8 tests of specimens would be needed. Here we outline a statistical model of strength that resembles a fishnet pulled diagonally, captures the tail of pdf of strength and, importantly, allows analytical safety assessments of nacreous materials. The analysis shows that, in terms of safety, the imbricated lamellar structure provides a major additional advantage—˜10% strength increase at tail failure probability 10^-6 and a 1 to 2 orders of magnitude tail probability decrease at fixed stress. Another advantage is that a high scatter of microstructure properties diminishes the strength difference between the mean and the probability tail, compared with the weakest link model. These advantages of nacre-like materials are here justified analytically and supported by millions of Monte Carlo simulations.

  16. Diamond knife-assisted deep anterior lamellar keratoplasty to manage keratoconus.

    Science.gov (United States)

    Vajpayee, Rasik B; Maharana, Prafulla K; Sharma, Namrata; Agarwal, Tushar; Jhanji, Vishal

    2014-02-01

    To evaluate the outcomes of a new surgical technique, diamond knife-assisted deep anterior lamellar keratoplasty (DALK), and compare its visual and refractive results with big-bubble DALK in cases of keratoconus. Tertiary eyecare hospital. Comparative case series. The visual and surgical outcomes of diamond knife-assisted DALK were compared with those of successful big-bubble DALK. Diamond knife-assisted DALK was performed in 19 eyes and big-bubble DALK, in 11 eyes. All surgeries were completed successfully. No intraoperative or postoperative complications occurred with diamond knife-assisted DALK. Six months after diamond knife-assisted DALK, the mean corrected distance visual acuity (CDVA) improved significantly from 1.87 logMAR ± 0.22 (SD) to 0.23 ± 0.06 logMAR, the mean keratometry improved from 65.99 ± 8.86 diopters (D) to 45.13 ± 1.16 D, and the mean keratometric cylinder improved from 7.99 ± 3.81 D to 2.87 ± 0.59 D (all P=.005). Postoperatively, the mean refractive astigmatism was 2.55 ± 0.49 D and the mean spherical equivalent was -1.97 ± 0.56 D. The mean logMAR CDVA (P = .06), postoperative keratometry (P=.64), refractive cylinder (P=.63), and endothelial cell loss (P=.11) were comparable between diamond knife-assisted DALK and big-bubble DALK. Diamond knife-assisted DALK was effective and predictable as a surgical technique for management of keratoconus cases. This technique has the potential to offer visual and refractive outcomes comparable to those of big-bubble DALK. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  17. Energetics of a hexagonal-lamellar-hexagonal-phase transition sequence in dioleoylphosphatidylethanolamine membranes

    International Nuclear Information System (INIS)

    Gawrisch, K.; Parsegian, V.A.; Hajduk, D.A.; Tate, M.W.; Gruner, S.M.; Fuller, N.L.; Rand, R.P.

    1992-01-01

    The phase diagram of DOPE/water dispersions was investigated by NMR and X-ray diffraction in the water concentration range from 2 to 20 water molecules per lipid and in the temperature range from -5 to +50C. At temperature above 22C, the dispersions form an inverse (H II ) phase at all water concentrations. Below 25C, an H II phase occurs at high water concentrations, an L α phase is formed at intermediate water concentrations, and finally the system switches back to an H II phase at low water concentrations. The enthalpy of the L α -H II -phase transition is +0.3 kcal/mol as measured by differential scanning calorimetry. Using 31 P and 2 H NMR and X-ray diffraction. The authors measured the trapped water volumes in H II and L α phases as a function of osmotic pressure. The change of the H II -phase free energy as a function of hydration was calculated by integrating the osmotic pressure vs trapped water volume curve. The phase diagram calculated on the basis of the known enthalpy of transition and the osmotic pressure vs water volume curves is in good agreement with the measured one. The H II -L α -H II double-phase transition at temperatures below 22C can be shown to be a consequence of (1) the greater degree of hydration of the H II phase in excess water and (2) the relative sensitivities with which the lamellar and hexagonal phases dehydrate with increasing osmotic pressure. These results demonstrate the usefulness of osmotic stress measurements to understand lipid-phase diagrams

  18. Intrastromal Corneal Ring Segments for Astigmatism Correction after Deep Anterior Lamellar Keratoplasty

    Directory of Open Access Journals (Sweden)

    Júlio C. D. Arantes

    2017-01-01

    Full Text Available Background. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK. Design was a longitudinal, retrospective, interventional study. The study included 25 eyes of 24 patients with keratoconus who had DALK performed at least two years prior to ICRS implantation. All patients had a clear corneal graft with up to 8.00 D of corneal astigmatism and intolerance to contact lenses. The studied parameters were age, sex, corrected distance visual acuity (CDVA, maximum keratometry (K1, minimum keratometry (K2, spherical equivalent, and astigmatism. There was a statistically significant decrease in the postintervention analysis as follows: 3.5 D reduction in K1 (p<0.001; 1.53 D in K2 (p=0.005; and 2.52 D (p<0.001 in the average K. The spherical equivalent reduced from −3.67 D (±2.74 to −0.71 D (±2.35 (p<0.001. The topographic astigmatism reduced from 3.87 D preoperatively to 1.90 D postoperatively (p<0.001. The CDVA improved from 0.33 (±0.10 to 0.20 (±0.09, p<0.001. ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results.

  19. Conformational dynamics of dry lamellar crystals of sugar based lipids: an atomistic simulation study.

    Directory of Open Access Journals (Sweden)

    Vijayan ManickamAchari

    Full Text Available The rational design of a glycolipid application (e.g. drug delivery with a tailored property depends on the detailed understanding of its structure and dynamics. Because of the complexity of sugar stereochemistry, we have undertaken a simulation study on the conformational dynamics of a set of synthetic glycosides with different sugar groups and chain design, namely dodecyl β-maltoside, dodecyl β-cellobioside, dodecyl β-isomaltoside and a C12C10 branched β-maltoside under anhydrous conditions. We examined the chain structure in detail, including the chain packing, gauche/trans conformations and chain tilting. In addition, we also investigated the rotational dynamics of the headgroup and alkyl chains. Monoalkylated glycosides possess a small amount of gauche conformers (∼20% in the hydrophobic region of the lamellar crystal (LC phase. In contrast, the branched chain glycolipid in the fluid Lα phase has a high gauche population of up to ∼40%. Rotational diffusion analysis reveals that the carbons closest to the headgroup have the highest correlation times. Furthermore, its value depends on sugar type, where the rotational dynamics of an isomaltose was found to be 11-15% and more restrained near the sugar, possibly due to the chain disorder and partial inter-digitation compared to the other monoalkylated lipids. Intriguingly, the present simulation demonstrates the chain from the branched glycolipid bilayer has the ability to enter into the hydrophilic region. This interesting feature of the anhydrous glycolipid bilayer simulation appears to arise from a combination of lipid crowding and the amphoteric nature of the sugar headgroups.

  20. Rheophysics of Lamellar Phases Rhéophysiques de phases lamellaires

    Directory of Open Access Journals (Sweden)

    Roux D.

    2006-12-01

    Full Text Available We have developed several techniques to study the effect of shear on complex fluids. These techniques are based on shear cells specially adapted to scattering techniques or transport properties. A brief description of the cells will be given together with the results that can be obtained using these techniques. Exemples on lyotropic systems will be detailed. The effect of shear on lyotropic lamellar phases is studied by light scattering, neutron scattering and microscopic observations. We found three different states of orientation separated with out-of-equilibrium transitions. In the state at very low shear rate, the lamellar phase is, in average, oriented with the layers in the shear plane and a few dislocations remains in the direction of the flow. In the intermediate state, the layers organize themselves into monodisperse multilayer vesicles (MLV whose size is controlled by the shear rate. The last state corresponds to the same orientation than the first one but with no dislocations in the flow direction. The second state of orientation : leading to the MLV structure, is more precisely studied. It is shown that the size of the MLV is fixed by a balance between the viscous and elastic stresses and varies as the inverse square root of the shear rate. A possible mechanism for the formation of this structure is proposed. We show that this structure can be swollen in a solvent leading to a monodisperse emulsion of a lamellar structure in an isotropic liquid. Linear and nonlinear rheological properties are measured and discussed. It is shown that the viscosity is sensitive to the structure and varies of several order of magnitude depending in which phase of orientation the system is. Both shear thickening and shear thinning are described and explanations in terms or orientation transitions are given. The discovery of the oriented to MLV instability is the basis a very efficient process leading to well controlled microcapsules made of surfactant

  1. Class of regular bouncing cosmologies

    Science.gov (United States)

    Vasilić, Milovan

    2017-06-01

    In this paper, I construct a class of everywhere regular geometric sigma models that possess bouncing solutions. Precisely, I show that every bouncing metric can be made a solution of such a model. My previous attempt to do so by employing one scalar field has failed due to the appearance of harmful singularities near the bounce. In this work, I use four scalar fields to construct a class of geometric sigma models which are free of singularities. The models within the class are parametrized by their background geometries. I prove that, whatever background is chosen, the dynamics of its small perturbations is classically stable on the whole time axis. Contrary to what one expects from the structure of the initial Lagrangian, the physics of background fluctuations is found to carry two tensor, two vector, and two scalar degrees of freedom. The graviton mass, which naturally appears in these models, is shown to be several orders of magnitude smaller than its experimental bound. I provide three simple examples to demonstrate how this is done in practice. In particular, I show that graviton mass can be made arbitrarily small.

  2. Organic alloy systems suitable for the investigation of regular binary and ternary eutectic growth

    Science.gov (United States)

    Sturz, L.; Witusiewicz, V. T.; Hecht, U.; Rex, S.

    2004-09-01

    Transparent organic alloys showing a plastic crystal phase were investigated experimentally using differential scanning calorimetry and directional solidification with respect to find a suitable model system for regular ternary eutectic growth. The temperature, enthalpy and entropy of phase transitions have been determined for a number of pure substances. A distinction of substances with and without plastic crystal phases was made from their entropy of melting. Binary phase diagrams were determined for selected plastic crystal alloys with the aim to identify eutectic reactions. Examples for lamellar and rod-like eutectic solidification microstructures in binary systems are given. The system (D)Camphor-Neopentylglycol-Succinonitrile is identified as a system that exhibits, among others, univariant and a nonvariant eutectic reaction. The ternary eutectic alloy close to the nonvariant eutectic composition solidifies with a partially faceted solid-liquid interface. However, by adding a small amount of Amino-Methyl-Propanediol (AMPD), the temperature of the nonvariant eutectic reaction and of the solid state transformation from plastic to crystalline state are shifted such, that regular eutectic growth with three distinct nonfaceted phases is observed in univariant eutectic reaction for the first time. The ternary phase diagram and examples for eutectic microstructures in the ternary and the quaternary eutectic alloy are given.

  3. Apodized coupled resonator waveguides.

    Science.gov (United States)

    Capmany, J; Muñoz, P; Domenech, J D; Muriel, M A

    2007-08-06

    In this paper we propose analyse the apodisation or windowing of the coupling coefficients in the unit cells of coupled resonator waveguide devices (CROWs) as a means to reduce the level of secondary sidelobes in the bandpass characteristic of their transfer functions. This technique is regularly employed in the design of digital filters and has been applied as well in the design of other photonic devices such as corrugated waveguide filters and fiber Bragg gratings. The apodisation of both Type-I and Type-II structures is discussed for several windowing functions.

  4. Effect of microstructure evolution of the lamellar alpha on impact toughness in a two-phase titanium alloy

    International Nuclear Information System (INIS)

    Xu, Jianwei; Zeng, Weidong; Zhao, Yawei; Jia, Zhiqiang

    2016-01-01

    The effects of the evolution of the lamellar alpha microstructure on the impact toughness of Ti-17 alloy are investigated. For this purpose, the beta-processed material is isothermally forged at 820 °C and subsequently heat treated using the combination of solid solution and aging treatment. Then the impact tests are carried out at room temperature. The corresponding microstructure and fracture surface are examined by scanning electron microscope (SEM). Microstructural observations reveal that globularization behavior is the main feature of microstructure evolution and the globularization fraction increases with the increasing of prestrain. However, globularization behavior has a negative influence on the impact toughness of Ti-17 alloy. In this work, the impact toughness have been obtained in the range of 29–55 J/cm 2 via varying globularization fraction of alpha phase. A linear relationship between the impact toughness and globularization fraction can be observed though the quantitative analysis. The linear equation is expressed as A=−0.3232f+59.885. The two major reasons can be used to explain the effect of globularization fraction on the impact property of Ti-17 alloy. One explanation is that the lamellar structure can provide excellent interfacial strengthening effect, which can improve the toughness of material, and makes it not easy to fracture. On the other hand, the fracture surface of specimen with the lamellar structure has larger amplitude of ups and downs. A long crack path length will be generated during fracture process. By contrast, the fracture of specimen with the equiaxed structure presents more flat surface and shorter crack path.

  5. Queratitis lamelar difusa después de un corte incompleto Diffuse lamellar keratitis after incomplete corneal flap cut

    Directory of Open Access Journals (Sweden)

    Yanaisa Riverón Ruiz

    2012-12-01

    Full Text Available La queratitis lamelar difusa es una inflamación estéril de la interfase lamelar que suele presentarse 24 horas después de la realización de la queratomileusis in situ asistida con láser y potencialmente puede comprometer la agudeza visual final. Se presenta un paciente de 25 años de edad con antecedentes de cirugía refractiva corneal mediante queratomileusis in situ con láser en el ojo derecho, que tuvo como complicación durante el acto quirúrgico un corte incompleto. En el posoperatorio inmediato se le diagnosticó una queratitis lamelar difusa. Se aplicó tratamiento local y se obtuvo la recuperación visual total del paciente con estabilidad del defecto refractivo. Esto permite posteriormente realizarle la corrección mediante cirugía refractiva de superficie.The diffuse lamellar keratitis is a sterile swelling of the lamellar interface which arises generally 24 hours after laser in situ keratomileusis and might affect the final visual acuity. A 25 years- old patient with history of corneal refractive surgery by laser in situ keratomileusis on his right eye was reported. He suffered from an incomplete corneal flap cut as complication during the surgical procedure, and a diffuse lamellar keratitis was detected at the immediate postsurgical visit. Total visual recovery and the refractive defect stability were attained through local treatment. This allows further correcting the defect by means of a surface refractive surgery in the future.

  6. The ultra-structural organization of the elastic network in the intra- and inter-lamellar matrix of the intervertebral disc.

    Science.gov (United States)

    Tavakoli, J; Elliott, D M; Costi, J J

    2017-08-01

    The inter-lamellar matrix (ILM)-located between adjacent lamellae of the annulus fibrosus-consists of a complex structure of elastic fibers, while elastic fibers of the intra-lamellar region are aligned predominantly parallel to the collagen fibers. The organization of elastic fibers under low magnification, in both inter- and intra-lamellar regions, was studied by light microscopic analysis of histologically prepared samples; however, little is known about their ultrastructure. An ultrastructural visualization of elastic fibers in the inter-lamellar matrix is crucial for describing their contribution to structural integrity, as well as mechanical properties of the annulus fibrosus. The aims of this study were twofold: first, to present an ultrastructural analysis of the elastic fiber network in the ILM and intra-lamellar region, including cross section (CS) and in-plane (IP) lamellae, of the AF using Scanning Electron Microscopy (SEM) and second, to -compare the elastic fiber orientation between the ILM and intra-lamellar region. Four samples (lumbar sheep discs) from adjacent sections (30μm thickness) of anterior annulus were partially digested by a developed NaOH-sonication method for visualization of elastic fibers by SEM. Elastic fiber orientation and distribution were quantified relative to the tangential to circumferential reference axis. Visualization of the ILM under high magnification revealed a dense network of elastic fibers that has not been previously described. Within the ILM, elastic fibers form a complex network, consisting of different size and shape fibers, which differed to those located in the intra-lamellar region. For both regions, the majority of fibers were oriented near 0° with respect to tangential to circumferential (TCD) direction and two minor symmetrical orientations of approximately±45°. Statistically, the orientation of elastic fibers between the ILM and intra-lamellar region was not different (p=0.171). The present study used

  7. The application of Lorentz transmission electron microscopy to the study of lamellar magnetism in hematite-ilmenite

    DEFF Research Database (Denmark)

    Kasama, Takeshi; Dunin-Borkowski, Rafal E.; Asaka, T

    2009-01-01

    . However, the magnitude of the experimental contrast is higher than that in the simulations, suggesting that an alternative origin for the observed asymmetry cannot be ruled out. Electron tomography was used to show that the lamellae have lens-like shapes and that (001) planes make up a significant...... in hematite. The likelihood that lamellar magnetism may be responsible for this contrast is assessed using simulations that incorporate interfacial magnetic moments on the (001) basal planes of hematite and ilmenite. The simulations suggest qualitatively that the asymmetric contrast is magnetic in origin...

  8. Small-angle neutron scattering investigation of the chain conformation of lamellar polystyrene/isoprene phase in solid state

    International Nuclear Information System (INIS)

    Constantinescu, L.M.

    1994-01-01

    Small-angle neutron scattering has been used in the study of chain conformation of lamellar styrene/isoprene block copolymers oriented in large single crystals. The radius of gyration of deuterated polystyrene chains around the normal to the interface has been measured. By comparing this direct evolution of the lateral dimension of the chains with the average chain separation given by the molecular area (the surface available at the interface for each covalent bond linking the blocks together) we characterized the transverse interpenetration degree of the chains. The polystyrene chains are displayed in simple strata own micro-domains, without an important interpenetration. (Author) 9 Figs., 2 Tabs., 25 Refs

  9. Fishnet statistics for probabilistic strength and scaling of nacreous imbricated lamellar materials

    Science.gov (United States)

    Luo, Wen; Bažant, Zdeněk P.

    2017-12-01

    Similar to nacre (or brick masonry), imbricated (or staggered) lamellar structures are widely found in nature and man-made materials, and are of interest for biomimetics. They can achieve high defect insensitivity and fracture toughness, as demonstrated in previous studies. But the probability distribution with a realistic far-left tail is apparently unknown. Here, strictly for statistical purposes, the microstructure of nacre is approximated by a diagonally pulled fishnet with quasibrittle links representing the shear bonds between parallel lamellae (or platelets). The probability distribution of fishnet strength is calculated as a sum of a rapidly convergent series of the failure probabilities after the rupture of one, two, three, etc., links. Each of them represents a combination of joint probabilities and of additive probabilities of disjoint events, modified near the zone of failed links by the stress redistributions caused by previously failed links. Based on previous nano- and multi-scale studies at Northwestern, the strength distribution of each link, characterizing the interlamellar shear bond, is assumed to be a Gauss-Weibull graft, but with a deeper Weibull tail than in Type 1 failure of non-imbricated quasibrittle materials. The autocorrelation length is considered equal to the link length. The size of the zone of failed links at maximum load increases with the coefficient of variation (CoV) of link strength, and also with fishnet size. With an increasing width-to-length aspect ratio, a rectangular fishnet gradually transits from the weakest-link chain to the fiber bundle, as the limit cases. The fishnet strength at failure probability 10-6 grows with the width-to-length ratio. For a square fishnet boundary, the strength at 10-6 failure probability is about 11% higher, while at fixed load the failure probability is about 25-times higher than it is for the non-imbricated case. This is a major safety advantage of the fishnet architecture over particulate

  10. Confocal microscopy findings in deep anterior lamellar keratoplasty performed after Descemet's stripping automated endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Pang A

    2014-01-01

    Full Text Available Audrey Pang,1,2 Karim Mohamed-Noriega,1 Anita S Chan,1,3–5 Jodbhir S Mehta1,3 1Singapore National Eye Centre, 2Department of Ophthalmology, Tan Tock Seng Hospital, 3Singapore Eye Research Institute, 4Department of Histopathology, Pathology, Singapore General Hospital, 5Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Background: This study describes the in vivo confocal microscopy findings in two patients who had deep anterior lamellar keratoplasty (DALK following Descemet's stripping automated endothelial keratoplasty (DSAEK. Methods: The study reviewed the cases of two patients who first underwent DSAEK followed by DALK when their vision failed to improve due to residual stromal scarring. In the first case, a DSAEK was performed for a patient with pseudophakic bullous keratopathy. After surgery, the patient's vision failed to improve satisfactorily due to residual anterior stromal opacity and irregularity. Subsequently, the patient underwent a DALK. The same two consecutive operations were performed for a second patient with keratoconus whose previous penetrating keratoplasty had failed and had secondary graft ectasia. In vivo confocal microscopy was performed 2 months after the DALK surgery in both cases. Results: At 3 months after DALK, the best-corrected visual acuity was 6/30 in case 1 and 6/24 in case 2. In vivo confocal microscopy in both cases revealed the presence of quiescent keratocytes in the stroma layers of the DSAEK and DALK grafts, which was similar in the central and peripheral cornea. There was no activated keratocytes or haze noted in the interface between the grafts. Conclusion: Our short-term results show that performing a DALK after a DSAEK is an effective way of restoring cornea clarity in patients with residual anterior stromal opacity. In vivo confocal microscopy showed that there were no activated keratocytes seen in the interface of the grafts, which suggests

  11. Adaptive regularization of noisy linear inverse problems

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Madsen, Kristoffer Hougaard; Lehn-Schiøler, Tue

    2006-01-01

    In the Bayesian modeling framework there is a close relation between regularization and the prior distribution over parameters. For prior distributions in the exponential family, we show that the optimal hyper-parameter, i.e., the optimal strength of regularization, satisfies a simple relation: T......: The expectation of the regularization function, i.e., takes the same value in the posterior and prior distribution. We present three examples: two simulations, and application in fMRI neuroimaging....

  12. Higher derivative regularization and chiral anomaly

    International Nuclear Information System (INIS)

    Nagahama, Yoshinori.

    1985-02-01

    A higher derivative regularization which automatically leads to the consistent chiral anomaly is analyzed in detail. It explicitly breaks all the local gauge symmetry but preserves global chiral symmetry and leads to the chirally symmetric consistent anomaly. This regularization thus clarifies the physics content contained in the consistent anomaly. We also briefly comment on the application of this higher derivative regularization to massless QED. (author)

  13. Regularity effect in prospective memory during aging

    Directory of Open Access Journals (Sweden)

    Geoffrey Blondelle

    2016-10-01

    Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

  14. Regularity effect in prospective memory during aging

    OpenAIRE

    Blondelle, Geoffrey; Hainselin, Mathieu; Gounden, Yannick; Heurley, Laurent; Voisin, Hélène; Megalakaki, Olga; Bressous, Estelle; Quaglino, Véronique

    2016-01-01

    Background: Regularity effect can affect performance in prospective memory (PM), but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults.Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30), 1...

  15. Bardeen regular black hole with an electric source

    Science.gov (United States)

    Rodrigues, Manuel E.; Silva, Marcos V. de S.

    2018-06-01

    If some energy conditions on the stress-energy tensor are violated, is possible construct regular black holes in General Relativity and in alternative theories of gravity. This type of solution has horizons but does not present singularities. The first regular black hole was presented by Bardeen and can be obtained from Einstein equations in the presence of an electromagnetic field. E. Ayon-Beato and A. Garcia reinterpreted the Bardeen metric as a magnetic solution of General Relativity coupled to a nonlinear electrodynamics. In this work, we show that the Bardeen model may also be interpreted as a solution of Einstein equations in the presence of an electric source, whose electric field does not behave as a Coulomb field. We analyzed the asymptotic forms of the Lagrangian for the electric case and also analyzed the energy conditions.

  16. Regularization and error assignment to unfolded distributions

    CERN Document Server

    Zech, Gunter

    2011-01-01

    The commonly used approach to present unfolded data only in graphical formwith the diagonal error depending on the regularization strength is unsatisfac-tory. It does not permit the adjustment of parameters of theories, the exclusionof theories that are admitted by the observed data and does not allow the com-bination of data from different experiments. We propose fixing the regulariza-tion strength by a p-value criterion, indicating the experimental uncertaintiesindependent of the regularization and publishing the unfolded data in additionwithout regularization. These considerations are illustrated with three differentunfolding and smoothing approaches applied to a toy example.

  17. Iterative Regularization with Minimum-Residual Methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2007-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  18. Iterative regularization with minimum-residual methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2006-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES - their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  19. Spectral phasor analysis of LAURDAN fluorescence in live A549 lung cells to study the hydration and time evolution of intracellular lamellar body-like structures

    DEFF Research Database (Denmark)

    Malacrida, Leonel; Astrada, Soledad; Briva, Arturo

    2016-01-01

    Using LAURDAN spectral imaging and spectral phasor analysis we concurrently studied the growth and hydration state of subcellular organelles (lamellar body-like, LB-like) from live A549 lung cancer cells at different post-confluence days. Our results reveal a time dependent two-step process...... governing the size and hydration of these intracellular LB-like structures. Specifically, a first step (days 1 to 7) is characterized by an increase in their size, followed by a second one (days 7 to 14) where the organelles display a decrease in their global hydration properties. Interestingly, our results...... also show that their hydration properties significantly differ from those observed in well-characterized artificial lamellar model membranes, challenging the notion that a pure lamellar membrane organization is present in these organelles at intracellular conditions. Finally, these LB-like structures...

  20. Diffuse lamellar keratitis after laser in situ keratomileusis with the Moria LSK-One and Carriazo-Barraquer microkeratomes.

    Science.gov (United States)

    Thammano, Pavika; Rana, Azhar N; Talamo, Jonathan H

    2003-10-01

    To assess risk factors for and incidence of diffuse lamellar keratitis (DLK) and to investigate whether microkeratome design is associated with the incidence of DLK. The Laser Eye Consultants of Boston, Boston and Waltham, Massachusetts, USA. In a retrospective nonrandomized comparative study, 1122 consecutive primary laser in situ keratomileusis (LASIK) treatments (584 patients) were analyzed to determine the incidence of DLK using 2 different microkeratome designs (Moria LSK-One [LSK] and Moria Carriazo-Barraquer [C-B]). The incidence of DLK was as determined by clinical signs. The overall incidence of DLK was 2.23%. The incidence in the LSK and C-B groups was 1.09% and 4.38%, respectively, with a statistically significant difference in incidence between the 2 groups (P<.01). Epithelial irregularities increased the risk for DLK. There was no significant statistical difference in sex, age, operating room location, type of laser, or time of day the surgery was performed between the 2 groups or between eyes that had DLK and eyes without DLK. The incidence of DLK using the C-B microkeratome fell significantly after May 2000, when new cleaning methods for this device were introduced. Different microkeratomes and how they are maintained may influence the incidence of DLK. Diffuse lamellar keratitis is more common after LASIK in a setting of epithelial irregularities, whether or not an actual epithelial defect is created.

  1. Stability of the lamellar structure in Mo-TiC eutectic composite under a low vacuum at high temperatures

    International Nuclear Information System (INIS)

    Goto, Shoji; Nishijima, Yuzo; Yoshinaga, Hideo

    1986-01-01

    Thermal stability of the lamellar structure in a Mo-TiC eutectic composite has been investigated through the heat-treatment at 1523 - 2223 K for 5.76 x 10 4 - 3.6 x 10 5 s under a low vacuum pressure of 13 mPa. It was found that the TiC phase in the eutectic lamellar disappeared above the critical temperature of about 1750 K, but below the critical temperature the disappearance of TiC phase was hardly observed and TiO film was formed on the surface. The Mo matrix phase was not oxidized and was stable at all test temperatures, since its affinity for oxygen is lower than that for carbon and titanium. It is presumed that at higer temperatures the disappearance process of TiC phase is controlled by the diffusion of carbon atoms through the matrix to the surface, and carbon and titanium atoms on the surface are removed by CO gas formation and TiO evaporation, respectively, but at lower temperatures the evaporation of TiO is so slow that the TiO film is formed on the surface. (author)

  2. Structure of lamellar lipid domains and corneocyte envelopes of murine stratum corneum. An X-ray diffraction study

    International Nuclear Information System (INIS)

    White, S.H.; Mirejovsky, D.; King, G.I.

    1988-01-01

    The lipid of the outermost layer of the skin is confined largely to the extracellular spaces surrounding the corneocytes of the stratum corneum where it forms a multilamellar adhesive matrix to act as the major permeability barrier of the skin. Knowledge of the molecular architecture of these intercellular domains is important for understanding various skin pathologies and their treatment, percutaneous drug delivery, and the cosmetic maintenance of the skin. The authors have surveyed by X-ray diffraction the structure of the intercellular domains and the extracted lipids of murine stratum corneum (SC) at 25, 45, and 70 0 C which are temperatures in the vicinity of known thermal phase transitions. The intercellular domains produce lamellar diffraction patterns with a Bragg spacing of 131 +/- 2 A. Lipid extracted from the SC and dispersed in excess water does not produce a simple lamellar diffraction pattern at any temperature studied, however. This and other facts suggest that another component, probably a protein, must be present to control the architecture of the intercellular lipid domains. They have also obtained diffraction patterns attributable to the protein envelopes of the corneocytes. The patterns suggest a β-pleated sheet organizational scheme. No diffraction patterns were observed that could be attributed to keratin

  3. A regularized stationary mean-field game

    KAUST Repository

    Yang, Xianjin

    2016-01-01

    In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

  4. A regularized stationary mean-field game

    KAUST Repository

    Yang, Xianjin

    2016-04-19

    In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

  5. On infinite regular and chiral maps

    OpenAIRE

    Arredondo, John A.; Valdez, Camilo Ramírez y Ferrán

    2015-01-01

    We prove that infinite regular and chiral maps take place on surfaces with at most one end. Moreover, we prove that an infinite regular or chiral map on an orientable surface with genus can only be realized on the Loch Ness monster, that is, the topological surface of infinite genus with one end.

  6. From recreational to regular drug use

    DEFF Research Database (Denmark)

    Järvinen, Margaretha; Ravn, Signe

    2011-01-01

    This article analyses the process of going from recreational use to regular and problematic use of illegal drugs. We present a model containing six career contingencies relevant for young people’s progress from recreational to regular drug use: the closing of social networks, changes in forms...

  7. Automating InDesign with Regular Expressions

    CERN Document Server

    Kahrel, Peter

    2006-01-01

    If you need to make automated changes to InDesign documents beyond what basic search and replace can handle, you need regular expressions, and a bit of scripting to make them work. This Short Cut explains both how to write regular expressions, so you can find and replace the right things, and how to use them in InDesign specifically.

  8. Regularization modeling for large-eddy simulation

    NARCIS (Netherlands)

    Geurts, Bernardus J.; Holm, D.D.

    2003-01-01

    A new modeling approach for large-eddy simulation (LES) is obtained by combining a "regularization principle" with an explicit filter and its inversion. This regularization approach allows a systematic derivation of the implied subgrid model, which resolves the closure problem. The central role of

  9. 29 CFR 779.18 - Regular rate.

    Science.gov (United States)

    2010-07-01

    ... employee under subsection (a) or in excess of the employee's normal working hours or regular working hours... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... not less than one and one-half times their regular rates of pay. Section 7(e) of the Act defines...

  10. Thermodynamic Product Relations for Generalized Regular Black Hole

    International Nuclear Information System (INIS)

    Pradhan, Parthapratim

    2016-01-01

    We derive thermodynamic product relations for four-parametric regular black hole (BH) solutions of the Einstein equations coupled with a nonlinear electrodynamics source. The four parameters can be described by the mass (m), charge (q), dipole moment (α), and quadrupole moment (β), respectively. We study its complete thermodynamics. We compute different thermodynamic products, that is, area product, BH temperature product, specific heat product, and Komar energy product, respectively. Furthermore, we show some complicated function of horizon areas that is indeed mass-independent and could turn out to be universal.

  11. Regular black holes: electrically charged solutions, Reissner-Nordstroem outside a De Sitter core

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Jose P.S. [Universidade Tecnica de Lisboa (CENTRA/IST/UTL) (Portugal). Instituto Superior Tecnico. Centro Multidisciplinar de Astrofisica; Zanchin, Vilson T. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas

    2011-07-01

    Full text: The understanding of the inside of a black hole is of crucial importance in order to have the correct picture of a black hole as a whole. The singularities that lurk inside of the usual black hole solutions are things to avoid. Their substitution by a regular part is of great interest, the process generating regular black holes. In the present work regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstroem, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several solutions: the regular nonextremal black holes with a null matter boundary, the regular nonextremal black holes with a timelike matter boundary, the regular extremal black holes with a timelike matter boundary, and the regular overcharged stars with a timelike matter boundary. The main physical and geometrical properties of such charged regular solutions are analyzed. (author)

  12. Differential regularization of a non-relativistic anyon model

    International Nuclear Information System (INIS)

    Freedman, D.Z.; Rius, N.

    1993-07-01

    Differential regularization is applied to a field theory of a non-relativistic charged boson field φ with λ(φ * φ) 2 self-interaction and coupling to a statistics-changing 0(1) Chern-Simons gauge field. Renormalized configuration-space amplitudes for all diagrams contributing to the φ * φ * φφ 4-point function, which is the only primitively divergent Green's function, are obtained up to 3-loop order. The renormalization group equations are explicitly checked, and the scheme dependence of the β-function is investigated. If the renormalization scheme is fixed to agree with a previous 1-loop calculation, the 2- and 3-loop contributions to β(λ, e) vanish, and β(λ, ε) itself vanishes when the ''self-dual'' condition relating λ to the gauge coupling e is imposed. (author). 12 refs, 1 fig

  13. On the overlap prescription for lattice regularization of chiral fermions

    Energy Technology Data Exchange (ETDEWEB)

    Randjbar-Daemi, S; Strathdee, J

    1995-12-01

    Feynman rules for the vacuum amplitude of fermions coupled to external gauge and Higgs fields in a domain wall lattice model are derived using time-dependent perturbation theory. They have a clear and simple structure corresponding to 1-loop vacuum graphs. Their continuum approximations are extracted by isolating the infrared singularities and it is shown that, in each order, they reduce to vacuum contributions for chiral fermions. In this sense the lattice model is seen to constitute a valid regularization of the continuum theory of chiral fermions coupled to weak and slowly varying gauge and Higgs fields. The overlap amplitude, while not gauge invariant, exhibits a well defined (module phase conventions) response to gauge transformations of the background fields. This response reduces in the continuum limit to the expected chiral anomaly, independently of the phase convention. (author). 20 refs.

  14. On the overlap prescription for lattice regularization of chiral fermions

    International Nuclear Information System (INIS)

    Randjbar-Daemi, S.; Strathdee, J.

    1995-12-01

    Feynman rules for the vacuum amplitude of fermions coupled to external gauge and Higgs fields in a domain wall lattice model are derived using time-dependent perturbation theory. They have a clear and simple structure corresponding to 1-loop vacuum graphs. Their continuum approximations are extracted by isolating the infrared singularities and it is shown that, in each order, they reduce to vacuum contributions for chiral fermions. In this sense the lattice model is seen to constitute a valid regularization of the continuum theory of chiral fermions coupled to weak and slowly varying gauge and Higgs fields. The overlap amplitude, while not gauge invariant, exhibits a well defined (module phase conventions) response to gauge transformations of the background fields. This response reduces in the continuum limit to the expected chiral anomaly, independently of the phase convention. (author). 20 refs

  15. An iterative method for Tikhonov regularization with a general linear regularization operator

    NARCIS (Netherlands)

    Hochstenbach, M.E.; Reichel, L.

    2010-01-01

    Tikhonov regularization is one of the most popular approaches to solve discrete ill-posed problems with error-contaminated data. A regularization operator and a suitable value of a regularization parameter have to be chosen. This paper describes an iterative method, based on Golub-Kahan

  16. Multiple graph regularized protein domain ranking

    KAUST Repository

    Wang, Jim Jing-Yan

    2012-11-19

    Background: Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods.Results: To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods.Conclusion: The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications. 2012 Wang et al; licensee BioMed Central Ltd.

  17. Multiple graph regularized protein domain ranking

    KAUST Repository

    Wang, Jim Jing-Yan; Bensmail, Halima; Gao, Xin

    2012-01-01

    Background: Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods.Results: To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods.Conclusion: The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications. 2012 Wang et al; licensee BioMed Central Ltd.

  18. Hierarchical regular small-world networks

    International Nuclear Information System (INIS)

    Boettcher, Stefan; Goncalves, Bruno; Guclu, Hasan

    2008-01-01

    Two new networks are introduced that resemble small-world properties. These networks are recursively constructed but retain a fixed, regular degree. They possess a unique one-dimensional lattice backbone overlaid by a hierarchical sequence of long-distance links, mixing real-space and small-world features. Both networks, one 3-regular and the other 4-regular, lead to distinct behaviors, as revealed by renormalization group studies. The 3-regular network is planar, has a diameter growing as √N with system size N, and leads to super-diffusion with an exact, anomalous exponent d w = 1.306..., but possesses only a trivial fixed point T c = 0 for the Ising ferromagnet. In turn, the 4-regular network is non-planar, has a diameter growing as ∼2 √(log 2 N 2 ) , exhibits 'ballistic' diffusion (d w = 1), and a non-trivial ferromagnetic transition, T c > 0. It suggests that the 3-regular network is still quite 'geometric', while the 4-regular network qualifies as a true small world with mean-field properties. As an engineering application we discuss synchronization of processors on these networks. (fast track communication)

  19. Multiple graph regularized protein domain ranking.

    Science.gov (United States)

    Wang, Jim Jing-Yan; Bensmail, Halima; Gao, Xin

    2012-11-19

    Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods. To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods. The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications.

  20. Multiple graph regularized protein domain ranking

    Directory of Open Access Journals (Sweden)

    Wang Jim

    2012-11-01

    Full Text Available Abstract Background Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods. Results To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods. Conclusion The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications.

  1. Diagrammatic methods in phase-space regularization

    International Nuclear Information System (INIS)

    Bern, Z.; Halpern, M.B.; California Univ., Berkeley

    1987-11-01

    Using the scalar prototype and gauge theory as the simplest possible examples, diagrammatic methods are developed for the recently proposed phase-space form of continuum regularization. A number of one-loop and all-order applications are given, including general diagrammatic discussions of the nogrowth theorem and the uniqueness of the phase-space stochastic calculus. The approach also generates an alternate derivation of the equivalence of the large-β phase-space regularization to the more conventional coordinate-space regularization. (orig.)

  2. J-regular rings with injectivities

    OpenAIRE

    Shen, Liang

    2010-01-01

    A ring $R$ is called a J-regular ring if R/J(R) is von Neumann regular, where J(R) is the Jacobson radical of R. It is proved that if R is J-regular, then (i) R is right n-injective if and only if every homomorphism from an $n$-generated small right ideal of $R$ to $R_{R}$ can be extended to one from $R_{R}$ to $R_{R}$; (ii) R is right FP-injective if and only if R is right (J, R)-FP-injective. Some known results are improved.

  3. Formation of lamellar cross bridges in the annulus fibrosus of the intervertebral disc is a consequence of vascular regression.

    Science.gov (United States)

    Smith, Lachlan J; Elliott, Dawn M

    2011-05-01

    Cross bridges are radial structures within the highly organized lamellar structure of the annulus fibrosus of the intervertebral disc that connect two or more non-consecutive lamellae. Their origin and function are unknown. During fetal development, blood vessels penetrate deep within the AF and recede during postnatal growth. We hypothesized that cross bridges are the pathways left by these receding blood vessels. Initially, the presence of cross bridges was confirmed in cadaveric human discs aged 25 and 53 years. Next, L1-L2 intervertebral discs (n=4) from sheep ranging in age from 75 days fetal gestation to adult were processed for paraffin histology. Mid-sagittal sections were immunostained for endothelial cell marker PECAM-1. The anterior and posterior AF were imaged using differential interference contrast microscopy, and the following parameters were quantified: total number of distinct lamellae, total number of cross bridges, percentage of cross bridges staining positive for PECAM-1, cross bridge penetration depth (% total lamellae), and PECAM-1 positive cross bridge penetration depth. Cross bridges were first observed at 100 days fetal gestation. The overall number peaked in neonates then remained relatively unchanged. The percentage of PECAM-1 positive cross bridges declined progressively from almost 100% at 100 days gestation to less than 10% in adults. Cross bridge penetration depth peaked in neonates then remained unchanged at subsequent ages. Depth of PECAM-1 positive cross bridges decreased progressively after birth. Findings were similar for both the anterior and posterior. The AF lamellar architecture is established early in development. It later becomes disrupted as a consequence of vascularization. Blood vessels then recede, perhaps due to increasing mechanical stresses in the surrounding matrix. In this study we present evidence that the pathways left by receding blood vessels remain as lamellar cross bridges. It is unclear whether the presence

  4. Gravitational Quasinormal Modes of Regular Phantom Black Hole

    Directory of Open Access Journals (Sweden)

    Jin Li

    2017-01-01

    Full Text Available We investigate the gravitational quasinormal modes (QNMs for a type of regular black hole (BH known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS, and anti-de Sitter (AdS. In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter b, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by b. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

  5. Regularized quasinormal modes for plasmonic resonators and open cavities

    Science.gov (United States)

    Kamandar Dezfouli, Mohsen; Hughes, Stephen

    2018-03-01

    Optical mode theory and analysis of open cavities and plasmonic particles is an essential component of optical resonator physics, offering considerable insight and efficiency for connecting to classical and quantum optical properties such as the Purcell effect. However, obtaining the dissipative modes in normalized form for arbitrarily shaped open-cavity systems is notoriously difficult, often involving complex spatial integrations, even after performing the necessary full space solutions to Maxwell's equations. The formal solutions are termed quasinormal modes, which are known to diverge in space, and additional techniques are frequently required to obtain more accurate field representations in the far field. In this work, we introduce a finite-difference time-domain technique that can be used to obtain normalized quasinormal modes using a simple dipole-excitation source, and an inverse Green function technique, in real frequency space, without having to perform any spatial integrations. Moreover, we show how these modes are naturally regularized to ensure the correct field decay behavior in the far field, and thus can be used at any position within and outside the resonator. We term these modes "regularized quasinormal modes" and show the reliability and generality of the theory by studying the generalized Purcell factor of dipole emitters near metallic nanoresonators, hybrid devices with metal nanoparticles coupled to dielectric waveguides, as well as coupled cavity-waveguides in photonic crystals slabs. We also directly compare our results with full-dipole simulations of Maxwell's equations without any approximations, and show excellent agreement.

  6. Generalized regular genus for manifolds with boundary

    Directory of Open Access Journals (Sweden)

    Paola Cristofori

    2003-05-01

    Full Text Available We introduce a generalization of the regular genus, a combinatorial invariant of PL manifolds ([10], which is proved to be strictly related, in dimension three, to generalized Heegaard splittings defined in [12].

  7. Geometric regularizations and dual conifold transitions

    International Nuclear Information System (INIS)

    Landsteiner, Karl; Lazaroiu, Calin I.

    2003-01-01

    We consider a geometric regularization for the class of conifold transitions relating D-brane systems on noncompact Calabi-Yau spaces to certain flux backgrounds. This regularization respects the SL(2,Z) invariance of the flux superpotential, and allows for computation of the relevant periods through the method of Picard-Fuchs equations. The regularized geometry is a noncompact Calabi-Yau which can be viewed as a monodromic fibration, with the nontrivial monodromy being induced by the regulator. It reduces to the original, non-monodromic background when the regulator is removed. Using this regularization, we discuss the simple case of the local conifold, and show how the relevant field-theoretic information can be extracted in this approach. (author)

  8. SALT-INDUCED TRANSITION FROM A MICELLAR TO A LAMELLAR LIQUID-CRYSTALLINE PHASE IN DILUTE MIXTURES OF ANIONIC AND NONIONIC SURFACTANTS IN AQUEOUS-SOLUTION

    NARCIS (Netherlands)

    SEIN, A; ENGBERTS, JBFN; VANDERLINDEN, E; VANDEPAS, JC

    In dilute mixtures of anionic surfactant, sodium dodecylbenzenesulfonate (NaDoBS), and nonionic poly(ethylene oxide) alkyl monoether (C13-15E(7)) a transition from a micellar to a lamellar phase is found at high salting-out electrolyte (NaCit) concentrations. With an increase of the salt

  9. The color tuning of PS-b-P2VP lamellar films with changing the alkyl chain length of 1-iodoalkanes.

    Science.gov (United States)

    Shin, Sung-Eui; Kim, Su-Young; Shin, Dong-Myung

    2011-05-01

    Photonic crystals with tunability in the visible or near-infrared region have drawn increasing attention for controlling and processing light for the active components of future display. We prepared polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) lamellar films which is hydrophobic block-hydrophilic polyelectrolyte block polymer of 57 kg/mol-b-57 kg/mol. The lamellar stacks, which is alternating layer of hydrophilic and hydrophobic moiety of PS-b-P2VP, are obtained by exposing the spin coated film under chloroform vapor. The band gaps of the lamellar films interestingly varied after immersion into the quaternizing solvents containing 5 wt% of iodomethane, iodoethane, 1-iodobutane, 1-iodopentane, 1-iodohexane and 1-iodooctane solubilized in n-hexane. The iodoalkanes reacted with pyridine groups in PS-b-P2VP and generated the alkyl pyridinium salts readily. The degree of quaternization, alkyl chain length of iodoalkane and the salt water concentration affects the spacing of layer structure of PS-b-P2VP. The iodomethane and iodohexane produced similar band gaps and salt concentration dependence. These results are very much dependent on the hydrophobic-hydrophilic characters of PS-b-P2VP lamellar surface.

  10. Fast and compact regular expression matching

    DEFF Research Database (Denmark)

    Bille, Philip; Farach-Colton, Martin

    2008-01-01

    We study 4 problems in string matching, namely, regular expression matching, approximate regular expression matching, string edit distance, and subsequence indexing, on a standard word RAM model of computation that allows logarithmic-sized words to be manipulated in constant time. We show how...... to improve the space and/or remove a dependency on the alphabet size for each problem using either an improved tabulation technique of an existing algorithm or by combining known algorithms in a new way....

  11. Regular-fat dairy and human health

    DEFF Research Database (Denmark)

    Astrup, Arne; Bradley, Beth H Rice; Brenna, J Thomas

    2016-01-01

    In recent history, some dietary recommendations have treated dairy fat as an unnecessary source of calories and saturated fat in the human diet. These assumptions, however, have recently been brought into question by current research on regular fat dairy products and human health. In an effort to......, cheese and yogurt, can be important components of an overall healthy dietary pattern. Systematic examination of the effects of dietary patterns that include regular-fat milk, cheese and yogurt on human health is warranted....

  12. Deterministic automata for extended regular expressions

    Directory of Open Access Journals (Sweden)

    Syzdykov Mirzakhmet

    2017-12-01

    Full Text Available In this work we present the algorithms to produce deterministic finite automaton (DFA for extended operators in regular expressions like intersection, subtraction and complement. The method like “overriding” of the source NFA(NFA not defined with subset construction rules is used. The past work described only the algorithm for AND-operator (or intersection of regular languages; in this paper the construction for the MINUS-operator (and complement is shown.

  13. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  14. Online Manifold Regularization by Dual Ascending Procedure

    OpenAIRE

    Sun, Boliang; Li, Guohui; Jia, Li; Zhang, Hui

    2013-01-01

    We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offline to online in this paper. Our algorithms are derived by gradient ascent in the dual function. For practical purpose, we propose two buffering strategies and two sparse approximations to reduce the computational complexity. Detailed experiments verify the utility of our approache...

  15. A comparative review between the updated models of Brazilian, United Kingdom and American eye banks and lamellar transplants

    Directory of Open Access Journals (Sweden)

    Gustavo Victor

    2014-12-01

    Full Text Available The corneal transplantation (CT is the most commonly performed type of transplant in the world and the Eye Banks are organizations whose capture, evaluate, preserve, store and distribute ocular tissues. With the evolution of surgical techniques and equipment for CT, the BOs had to evolve to keep up with these requirements. This evolution goes from tissues capture techniques, donating money and clarification to the patient (e.g. internet-based, use of current equipment for more adequate tissues supply for the most current surgical techniques, integration of BOs of certain country and real-time management of stocks of ocular tissues, and adequacy of laws that manage the entire process. This review aims to make a comparative review between the updated models of Brazilian, United Kingdon and American Eye Banks. Like, check what the trend towards lamellar transplants in these three countries.

  16. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  17. Three-dimensional structure of human lamellar bone: the presence of two different materials and new insights into the hierarchical organization.

    Science.gov (United States)

    Reznikov, Natalie; Shahar, Ron; Weiner, Steve

    2014-02-01

    Lamellar bone is the most common bone type in humans. The predominant components of individual lamellae are plywood-like arrays of mineralized collagen fibrils aligned in different directions. Using a dual-beam electron microscope and the Serial Surface View (SSV) method we previously identified a small, but significantly different layer in rat lamellar bone, namely a disordered layer with collagen fibrils showing little or no preferred orientation. Here we present a 3D structural analysis of 12 SSV volumes (25 complete lamellae) from femora of 3 differently aged human individuals. We identify the ordered and disordered motifs in human bone as in the rat, with several significant differences. The ordered motif shows two major preferred orientations, perpendicular to the long axis of the bone, and aligned within 10-20° of the long axis, as well as fanning arrays. At a higher organizational level, arrays of ordered collagen fibrils are organized into 'rods' around 2 to 3μm in diameter, and the long axes of these 'rods' are parallel to the lamellar boundaries. Human bone also contains a disordered component that envelopes the rods and fills in the spaces between them. The disordered motif is especially well-defined between adjacent layers of rods. The disordered motif and its interfibrillar substance stain heavily with osmium tetroxide and Alcian blue indicating the presence of another organic component in addition to collagen. The canalicular network is confined to the disordered material, along with voids and individual collagen fibrils, some of which are also aligned more or less perpendicular to the lamellar boundaries. The organization of the ordered fibril arrays into rods enveloped in the continuous disordered structure was not observed in rat lamellar bone. We thus conclude that human lamellar bone is comprised of two distinct materials, an ordered material and a disordered material, and contains an additional hierarchical level of organization composed of

  18. Improved osteoblasts growth on osteomimetic hydroxyapatite/BaTiO_3 composites with aligned lamellar porous structure

    International Nuclear Information System (INIS)

    Liu, Beilei; Chen, Liangjian; Shao, Chunsheng; Zhang, Fuqiang; Zhou, Kechao; Cao, Jun; Zhang, Dou

    2016-01-01

    Osteoblasts growing into bone substitute is an important step of bone regeneration. This study prepared porous hydroxyapatite (HA)/BaTiO_3 piezoelectric composites with porosity of 40%, 50% and 60% by ice-templating method. Effects of HA/BaTiO_3 composites with different porosities, with and without polarizing treatment on adhesion, proliferation and differentiation of osteoblasts were investigated in vitro. Results revealed that cell densities of the porous groups were significantly higher than those of the dense group (p 0.05). The absence of mechanical loading on the polarized samples may account for this. The results indicated that hierarchically porous HA/BaTiO_3 played a favorable part in osteoblasts proliferation, differentiation and adhesion process and is a promising bone substitute material. - Graphical abstract: Aligned porous structure of HA/BaTiO_3 piezoelectric composites prepared by ice-templating method was similar to the lamellar Haversian system in bone tissue. When co-cultured with human osteosarcoma cells (MG63), porous HA/BaTiO_3 composites exhibited remarkable biological activity in promoting proliferation, differentiation and adhesion of MG63 cells. - Highlights: • The aligned porous structure of HA/BaTiO_3 composite was similar to the lamellar Haversian system in bone tissue. • The piezoelectric d_3_3 coefficient of HA/BaTiO_3 with porosity of 50% was 5.0 pC/N, much higher than that of natural bone. • HA/BaTiO_3 with porosity of 50% promoted proliferation, differentiation and adhesion of MG63 cells remarkably.

  19. DNA hosted and aligned in aqueous interstitia of a lamellar liquid crystal – a membrane–biomacromolecule interaction model system

    KAUST Repository

    Carlsson, Nils; Jonsson, Fabian; Wilhelmsson, L. Marcus; Nordé n, Bengt; Å kerman, Bjö rn

    2013-01-01

    We report that DNA molecules can be intercalated and macroscopically oriented in the aqueous interstitia of a lyotropic lamellar liquid crystal. Using UV-vis linear dichroism and fluorescence spectroscopy we show that double-stranded oligonucleotides (25 base pairs) in the water-octanoate-decanol system remain base-paired in the B conformation and are confined in two dimensions, with the helix axis preferentially parallel to the lipid bilayer surfaces but free to rotate within this plane. The degree of helix confinement and the corresponding 2-D orientation can be improved by decreasing the thickness of the water interstitia via the fraction of water in the ternary mixture. Not surprisingly, the corresponding single-stranded oligonucleotides are not aligned, with their persistence length being short in comparison to the lamellar interstitium thickness. We propose this as a model system for studying interactions of DNA-ligand complexes near a lipid bilayer membrane which we demonstrate by using dye probes that are either covalently attached to one end of the oligonucleotide or reversibly bound by intercalation between the base pairs. Three cationic dyes, all strongly bound by intercalation to DNA when free in solution, are found to not bind to DNA but to prefer the membrane surface. The covalently attached Cy5 also binds to the bilayer while Cy3 tends to end-stack to the oligonucleotide duplex. The orientation of Cy5 parallel to the membrane indicates that electrostatic surface binding predominates over insertion into the hydrophobic interior of the membrane. Anionic and zwitterionic dyes (FAM and ROX) are found to remain randomly oriented in the water between the lipid bilayer surfaces. © The Royal Society of Chemistry.

  20. Modeling and simulation of deformation and fracture behavior of components made of fully lamellar {gamma}TiAl alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kabir, Mohammad Rizviul [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2008-07-01

    The present work deals with the modeling and simulation of deformation and fracture behavior of fully lamellar {gamma}TiAl alloy; focusing on understanding the variability of local material properties and their influences on translamellar fracture. Afracture model has been presented that takes the inhomogeneity of the local deformation behavior of the lamellar colonies as well as the variability in fracture strength and toughness into consideration. To obtain the necessary model parameters, a hybrid methodology of experiments and simulations has been adopted. The experiments were performed at room temperature that demonstrates quasi-brittle response of the TiAl polycrystal. Aremarkable variation in stress-strain curves has been found in the tensile tests. Additional fracture tests showed significant variations in crack initiation and propagation during translamellar fracture. Analyzing the fracture surfaces, the micromechanical causes of these macroscopic scatter have been explained. The investigation shows that the global scatter in deformation and fracture response is highly influenced by the colony orientation and tilting angle with respect to the loading axis. The deformation and fracture behavior have been simulated by a finite element model including the material decohesion process described by a cohesive model. In order to capture the scatter of the macroscopic behavior, a stochastic approach is chosen. The local variability of stressstrain in the polycrystal and the variability of fracture parameters of the colonies are implemented in the stochastic approach of the cohesive model. It has been shown that the proposed approach is able to predict the stochastic nature of crack initiation and propagation as observed from the experiments. The global specimen failure with stable or unstable crack propagation can be explained in terms of the local variation of material properties. (orig.)

  1. Spiking Regularity and Coherence in Complex Hodgkin–Huxley Neuron Networks

    International Nuclear Information System (INIS)

    Zhi-Qiang, Sun; Ping, Xie; Wei, Li; Peng-Ye, Wang

    2010-01-01

    We study the effects of the strength of coupling between neurons on the spiking regularity and coherence in a complex network with randomly connected Hodgkin–Huxley neurons driven by colored noise. It is found that for the given topology realization and colored noise correlation time, there exists an optimal strength of coupling, at which the spiking regularity of the network reaches the best level. Moreover, when the temporal regularity reaches the best level, the spatial coherence of the system has already increased to a relatively high level. In addition, for the given number of neurons and noise correlation time, the values of average regularity and spatial coherence at the optimal strength of coupling are nearly independent of the topology realization. Furthermore, there exists an optimal value of colored noise correlation time at which the spiking regularity can reach its best level. These results may be helpful for understanding of the real neuron world. (cross-disciplinary physics and related areas of science and technology)

  2. Improvements in GRACE Gravity Fields Using Regularization

    Science.gov (United States)

    Save, H.; Bettadpur, S.; Tapley, B. D.

    2008-12-01

    The unconstrained global gravity field models derived from GRACE are susceptible to systematic errors that show up as broad "stripes" aligned in a North-South direction on the global maps of mass flux. These errors are believed to be a consequence of both systematic and random errors in the data that are amplified by the nature of the gravity field inverse problem. These errors impede scientific exploitation of the GRACE data products, and limit the realizable spatial resolution of the GRACE global gravity fields in certain regions. We use regularization techniques to reduce these "stripe" errors in the gravity field products. The regularization criteria are designed such that there is no attenuation of the signal and that the solutions fit the observations as well as an unconstrained solution. We have used a computationally inexpensive method, normally referred to as "L-ribbon", to find the regularization parameter. This paper discusses the characteristics and statistics of a 5-year time-series of regularized gravity field solutions. The solutions show markedly reduced stripes, are of uniformly good quality over time, and leave little or no systematic observation residuals, which is a frequent consequence of signal suppression from regularization. Up to degree 14, the signal in regularized solution shows correlation greater than 0.8 with the un-regularized CSR Release-04 solutions. Signals from large-amplitude and small-spatial extent events - such as the Great Sumatra Andaman Earthquake of 2004 - are visible in the global solutions without using special post-facto error reduction techniques employed previously in the literature. Hydrological signals as small as 5 cm water-layer equivalent in the small river basins, like Indus and Nile for example, are clearly evident, in contrast to noisy estimates from RL04. The residual variability over the oceans relative to a seasonal fit is small except at higher latitudes, and is evident without the need for de-striping or

  3. Regular Expression Matching and Operational Semantics

    Directory of Open Access Journals (Sweden)

    Asiri Rathnayake

    2011-08-01

    Full Text Available Many programming languages and tools, ranging from grep to the Java String library, contain regular expression matchers. Rather than first translating a regular expression into a deterministic finite automaton, such implementations typically match the regular expression on the fly. Thus they can be seen as virtual machines interpreting the regular expression much as if it were a program with some non-deterministic constructs such as the Kleene star. We formalize this implementation technique for regular expression matching using operational semantics. Specifically, we derive a series of abstract machines, moving from the abstract definition of matching to increasingly realistic machines. First a continuation is added to the operational semantics to describe what remains to be matched after the current expression. Next, we represent the expression as a data structure using pointers, which enables redundant searches to be eliminated via testing for pointer equality. From there, we arrive both at Thompson's lockstep construction and a machine that performs some operations in parallel, suitable for implementation on a large number of cores, such as a GPU. We formalize the parallel machine using process algebra and report some preliminary experiments with an implementation on a graphics processor using CUDA.

  4. Regularities, Natural Patterns and Laws of Nature

    Directory of Open Access Journals (Sweden)

    Stathis Psillos

    2014-02-01

    Full Text Available  The goal of this paper is to sketch an empiricist metaphysics of laws of nature. The key idea is that there are regularities without regularity-enforcers. Differently put, there are natural laws without law-makers of a distinct metaphysical kind. This sketch will rely on the concept of a natural pattern and more significantly on the existence of a network of natural patterns in nature. The relation between a regularity and a pattern will be analysed in terms of mereology.  Here is the road map. In section 2, I will briefly discuss the relation between empiricism and metaphysics, aiming to show that an empiricist metaphysics is possible. In section 3, I will offer arguments against stronger metaphysical views of laws. Then, in section 4 I will motivate nomic objectivism. In section 5, I will address the question ‘what is a regularity?’ and will develop a novel answer to it, based on the notion of a natural pattern. In section 6, I will raise the question: ‘what is a law of nature?’, the answer to which will be: a law of nature is a regularity that is characterised by the unity of a natural pattern.

  5. Regularization of absorber or doorway states in heavy-particle collisions

    International Nuclear Information System (INIS)

    Errea, L.F.; Riera, A.; Sanchez, P.

    1994-01-01

    We present a unified theoretical basis of the recently proposed regularization method of absorber or doorway states. The theory is applicable to the close-coupling solutions of time-dependent Schroedinger equations corresponding to Hamiltonians containing singular terms and with a partial continuum spectrum. The presentation and illustration are restricted to the treatment of atomic collisions. (author)

  6. Fractional Regularization Term for Variational Image Registration

    Directory of Open Access Journals (Sweden)

    Rafael Verdú-Monedero

    2009-01-01

    Full Text Available Image registration is a widely used task of image analysis with applications in many fields. Its classical formulation and current improvements are given in the spatial domain. In this paper a regularization term based on fractional order derivatives is formulated. This term is defined and implemented in the frequency domain by translating the energy functional into the frequency domain and obtaining the Euler-Lagrange equations which minimize it. The new regularization term leads to a simple formulation and design, being applicable to higher dimensions by using the corresponding multidimensional Fourier transform. The proposed regularization term allows for a real gradual transition from a diffusion registration to a curvature registration which is best suited to some applications and it is not possible in the spatial domain. Results with 3D actual images show the validity of this approach.

  7. Regular non-twisting S-branes

    International Nuclear Information System (INIS)

    Obregon, Octavio; Quevedo, Hernando; Ryan, Michael P.

    2004-01-01

    We construct a family of time and angular dependent, regular S-brane solutions which corresponds to a simple analytical continuation of the Zipoy-Voorhees 4-dimensional vacuum spacetime. The solutions are asymptotically flat and turn out to be free of singularities without requiring a twist in space. They can be considered as the simplest non-singular generalization of the singular S0-brane solution. We analyze the properties of a representative of this family of solutions and show that it resembles to some extent the asymptotic properties of the regular Kerr S-brane. The R-symmetry corresponds, however, to the general lorentzian symmetry. Several generalizations of this regular solution are derived which include a charged S-brane and an additional dilatonic field. (author)

  8. Online Manifold Regularization by Dual Ascending Procedure

    Directory of Open Access Journals (Sweden)

    Boliang Sun

    2013-01-01

    Full Text Available We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offline to online in this paper. Our algorithms are derived by gradient ascent in the dual function. For practical purpose, we propose two buffering strategies and two sparse approximations to reduce the computational complexity. Detailed experiments verify the utility of our approaches. An important conclusion is that our online MR algorithms can handle the settings where the target hypothesis is not fixed but drifts with the sequence of examples. We also recap and draw connections to earlier works. This paper paves a way to the design and analysis of online manifold regularization algorithms.

  9. Regular transport dynamics produce chaotic travel times.

    Science.gov (United States)

    Villalobos, Jorge; Muñoz, Víctor; Rogan, José; Zarama, Roberto; Johnson, Neil F; Toledo, Benjamín; Valdivia, Juan Alejandro

    2014-06-01

    In the hope of making passenger travel times shorter and more reliable, many cities are introducing dedicated bus lanes (e.g., Bogota, London, Miami). Here we show that chaotic travel times are actually a natural consequence of individual bus function, and hence of public transport systems more generally, i.e., chaotic dynamics emerge even when the route is empty and straight, stops and lights are equidistant and regular, and loading times are negligible. More generally, our findings provide a novel example of chaotic dynamics emerging from a single object following Newton's laws of motion in a regularized one-dimensional system.

  10. Regularity of difference equations on Banach spaces

    CERN Document Server

    Agarwal, Ravi P; Lizama, Carlos

    2014-01-01

    This work introduces readers to the topic of maximal regularity for difference equations. The authors systematically present the method of maximal regularity, outlining basic linear difference equations along with relevant results. They address recent advances in the field, as well as basic semigroup and cosine operator theories in the discrete setting. The authors also identify some open problems that readers may wish to take up for further research. This book is intended for graduate students and researchers in the area of difference equations, particularly those with advance knowledge of and interest in functional analysis.

  11. PET regularization by envelope guided conjugate gradients

    International Nuclear Information System (INIS)

    Kaufman, L.; Neumaier, A.

    1996-01-01

    The authors propose a new way to iteratively solve large scale ill-posed problems and in particular the image reconstruction problem in positron emission tomography by exploiting the relation between Tikhonov regularization and multiobjective optimization to obtain iteratively approximations to the Tikhonov L-curve and its corner. Monitoring the change of the approximate L-curves allows us to adjust the regularization parameter adaptively during a preconditioned conjugate gradient iteration, so that the desired solution can be reconstructed with a small number of iterations

  12. Matrix regularization of embedded 4-manifolds

    International Nuclear Information System (INIS)

    Trzetrzelewski, Maciej

    2012-01-01

    We consider products of two 2-manifolds such as S 2 ×S 2 , embedded in Euclidean space and show that the corresponding 4-volume preserving diffeomorphism algebra can be approximated by a tensor product SU(N)⊗SU(N) i.e. functions on a manifold are approximated by the Kronecker product of two SU(N) matrices. A regularization of the 4-sphere is also performed by constructing N 2 ×N 2 matrix representations of the 4-algebra (and as a byproduct of the 3-algebra which makes the regularization of S 3 also possible).

  13. On a correspondence between regular and non-regular operator monotone functions

    DEFF Research Database (Denmark)

    Gibilisco, P.; Hansen, Frank; Isola, T.

    2009-01-01

    We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information....

  14. Entrepreneurial Couples

    DEFF Research Database (Denmark)

    Dahl, Michael S.; Van Praag, Mirjam; Thompson, Peter

    2015-01-01

    We study possible motivations for co-entreprenurial couples to start up a joint firm, using a sample of 1,069 Danish couples that established a joint enterprise between 2001 and 2010. We compare their pre-entry characteristics, firm performance and post-dissolution private and financial outcomes...

  15. Localized chaoticity in two linearly coupled inverted double-well ...

    African Journals Online (AJOL)

    Two linearly coupled inverted double-well oscillators for a fixed energy and varying coupling strength were studied. The dynamics yielded a chaotic system in which the Poincare surface was characterised by two non-mixing regions, one of regular motion and the other region that became chaotic as the coupling increased.

  16. Regularity and irreversibility of weekly travel behavior

    NARCIS (Netherlands)

    Kitamura, R.; van der Hoorn, A.I.J.M.

    1987-01-01

    Dynamic characteristics of travel behavior are analyzed in this paper using weekly travel diaries from two waves of panel surveys conducted six months apart. An analysis of activity engagement indicates the presence of significant regularity in weekly activity participation between the two waves.

  17. Regular and context-free nominal traces

    DEFF Research Database (Denmark)

    Degano, Pierpaolo; Ferrari, Gian-Luigi; Mezzetti, Gianluca

    2017-01-01

    Two kinds of automata are presented, for recognising new classes of regular and context-free nominal languages. We compare their expressive power with analogous proposals in the literature, showing that they express novel classes of languages. Although many properties of classical languages hold ...

  18. Faster 2-regular information-set decoding

    NARCIS (Netherlands)

    Bernstein, D.J.; Lange, T.; Peters, C.P.; Schwabe, P.; Chee, Y.M.

    2011-01-01

    Fix positive integers B and w. Let C be a linear code over F 2 of length Bw. The 2-regular-decoding problem is to find a nonzero codeword consisting of w length-B blocks, each of which has Hamming weight 0 or 2. This problem appears in attacks on the FSB (fast syndrome-based) hash function and

  19. Complexity in union-free regular languages

    Czech Academy of Sciences Publication Activity Database

    Jirásková, G.; Masopust, Tomáš

    2011-01-01

    Roč. 22, č. 7 (2011), s. 1639-1653 ISSN 0129-0541 Institutional research plan: CEZ:AV0Z10190503 Keywords : Union-free regular language * one-cycle-free-path automaton * descriptional complexity Subject RIV: BA - General Mathematics Impact factor: 0.379, year: 2011 http://www.worldscinet.com/ijfcs/22/2207/S0129054111008933.html

  20. Regular Gleason Measures and Generalized Effect Algebras

    Science.gov (United States)

    Dvurečenskij, Anatolij; Janda, Jiří

    2015-12-01

    We study measures, finitely additive measures, regular measures, and σ-additive measures that can attain even infinite values on the quantum logic of a Hilbert space. We show when particular classes of non-negative measures can be studied in the frame of generalized effect algebras.

  1. Regularization of finite temperature string theories

    International Nuclear Information System (INIS)

    Leblanc, Y.; Knecht, M.; Wallet, J.C.

    1990-01-01

    The tachyonic divergences occurring in the free energy of various string theories at finite temperature are eliminated through the use of regularization schemes and analytic continuations. For closed strings, we obtain finite expressions which, however, develop an imaginary part above the Hagedorn temperature, whereas open string theories are still plagued with dilatonic divergences. (orig.)

  2. A Sim(2 invariant dimensional regularization

    Directory of Open Access Journals (Sweden)

    J. Alfaro

    2017-09-01

    Full Text Available We introduce a Sim(2 invariant dimensional regularization of loop integrals. Then we can compute the one loop quantum corrections to the photon self energy, electron self energy and vertex in the Electrodynamics sector of the Very Special Relativity Standard Model (VSRSM.

  3. Continuum regularized Yang-Mills theory

    International Nuclear Information System (INIS)

    Sadun, L.A.

    1987-01-01

    Using the machinery of stochastic quantization, Z. Bern, M. B. Halpern, C. Taubes and I recently proposed a continuum regularization technique for quantum field theory. This regularization may be implemented by applying a regulator to either the (d + 1)-dimensional Parisi-Wu Langevin equation or, equivalently, to the d-dimensional second order Schwinger-Dyson (SD) equations. This technique is non-perturbative, respects all gauge and Lorentz symmetries, and is consistent with a ghost-free gauge fixing (Zwanziger's). This thesis is a detailed study of this regulator, and of regularized Yang-Mills theory, using both perturbative and non-perturbative techniques. The perturbative analysis comes first. The mechanism of stochastic quantization is reviewed, and a perturbative expansion based on second-order SD equations is developed. A diagrammatic method (SD diagrams) for evaluating terms of this expansion is developed. We apply the continuum regulator to a scalar field theory. Using SD diagrams, we show that all Green functions can be rendered finite to all orders in perturbation theory. Even non-renormalizable theories can be regularized. The continuum regulator is then applied to Yang-Mills theory, in conjunction with Zwanziger's gauge fixing. A perturbative expansion of the regulator is incorporated into the diagrammatic method. It is hoped that the techniques discussed in this thesis will contribute to the construction of a renormalized Yang-Mills theory is 3 and 4 dimensions

  4. Gravitational lensing by a regular black hole

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F; Sendra, Carlos M

    2011-01-01

    In this paper, we study a regular Bardeen black hole as a gravitational lens. We find the strong deflection limit for the deflection angle, from which we obtain the positions and magnifications of the relativistic images. As an example, we apply the results to the particular case of the supermassive black hole at the center of our galaxy.

  5. Gravitational lensing by a regular black hole

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F; Sendra, Carlos M, E-mail: eiroa@iafe.uba.ar, E-mail: cmsendra@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, CC 67, Suc. 28, 1428, Buenos Aires (Argentina)

    2011-04-21

    In this paper, we study a regular Bardeen black hole as a gravitational lens. We find the strong deflection limit for the deflection angle, from which we obtain the positions and magnifications of the relativistic images. As an example, we apply the results to the particular case of the supermassive black hole at the center of our galaxy.

  6. Analytic stochastic regularization and gange invariance

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Lima-Santos, A.

    1986-05-01

    A proof that analytic stochastic regularization breaks gauge invariance is presented. This is done by an explicit one loop calculation of the vaccum polarization tensor in scalar electrodynamics, which turns out not to be transversal. The counterterm structure, Langevin equations and the construction of composite operators in the general framework of stochastic quantization, are also analysed. (Author) [pt

  7. Annotation of regular polysemy and underspecification

    DEFF Research Database (Denmark)

    Martínez Alonso, Héctor; Pedersen, Bolette Sandford; Bel, Núria

    2013-01-01

    We present the result of an annotation task on regular polysemy for a series of seman- tic classes or dot types in English, Dan- ish and Spanish. This article describes the annotation process, the results in terms of inter-encoder agreement, and the sense distributions obtained with two methods...

  8. Stabilization, pole placement, and regular implementability

    NARCIS (Netherlands)

    Belur, MN; Trentelman, HL

    In this paper, we study control by interconnection of linear differential systems. We give necessary and sufficient conditions for regular implementability of a-given linear, differential system. We formulate the problems of stabilization and pole placement as problems of finding a suitable,

  9. 12 CFR 725.3 - Regular membership.

    Science.gov (United States)

    2010-01-01

    ... UNION ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.3 Regular membership. (a) A natural person credit....5(b) of this part, and forwarding with its completed application funds equal to one-half of this... 1, 1979, is not required to forward these funds to the Facility until October 1, 1979. (3...

  10. Supervised scale-regularized linear convolutionary filters

    DEFF Research Database (Denmark)

    Loog, Marco; Lauze, Francois Bernard

    2017-01-01

    also be solved relatively efficient. All in all, the idea is to properly control the scale of a trained filter, which we solve by introducing a specific regularization term into the overall objective function. We demonstrate, on an artificial filter learning problem, the capabil- ities of our basic...

  11. On regular riesz operators | Raubenheimer | Quaestiones ...

    African Journals Online (AJOL)

    The r-asymptotically quasi finite rank operators on Banach lattices are examples of regular Riesz operators. We characterise Riesz elements in a subalgebra of a Banach algebra in terms of Riesz elements in the Banach algebra. This enables us to characterise r-asymptotically quasi finite rank operators in terms of adjoint ...

  12. Regularized Discriminant Analysis: A Large Dimensional Study

    KAUST Repository

    Yang, Xiaoke

    2018-04-28

    In this thesis, we focus on studying the performance of general regularized discriminant analysis (RDA) classifiers. The data used for analysis is assumed to follow Gaussian mixture model with different means and covariances. RDA offers a rich class of regularization options, covering as special cases the regularized linear discriminant analysis (RLDA) and the regularized quadratic discriminant analysis (RQDA) classi ers. We analyze RDA under the double asymptotic regime where the data dimension and the training size both increase in a proportional way. This double asymptotic regime allows for application of fundamental results from random matrix theory. Under the double asymptotic regime and some mild assumptions, we show that the asymptotic classification error converges to a deterministic quantity that only depends on the data statistical parameters and dimensions. This result not only implicates some mathematical relations between the misclassification error and the class statistics, but also can be leveraged to select the optimal parameters that minimize the classification error, thus yielding the optimal classifier. Validation results on the synthetic data show a good accuracy of our theoretical findings. We also construct a general consistent estimator to approximate the true classification error in consideration of the unknown previous statistics. We benchmark the performance of our proposed consistent estimator against classical estimator on synthetic data. The observations demonstrate that the general estimator outperforms others in terms of mean squared error (MSE).

  13. Complexity in union-free regular languages

    Czech Academy of Sciences Publication Activity Database

    Jirásková, G.; Masopust, Tomáš

    2011-01-01

    Roč. 22, č. 7 (2011), s. 1639-1653 ISSN 0129-0541 Institutional research plan: CEZ:AV0Z10190503 Keywords : Union-free regular language * one-cycle-free- path automaton * descriptional complexity Subject RIV: BA - General Mathematics Impact factor: 0.379, year: 2011 http://www.worldscinet.com/ijfcs/22/2207/S0129054111008933.html

  14. Bit-coded regular expression parsing

    DEFF Research Database (Denmark)

    Nielsen, Lasse; Henglein, Fritz

    2011-01-01

    the DFA-based parsing algorithm due to Dub ´e and Feeley to emit the bits of the bit representation without explicitly materializing the parse tree itself. We furthermore show that Frisch and Cardelli’s greedy regular expression parsing algorithm can be straightforwardly modified to produce bit codings...

  15. Improved osteoblasts growth on osteomimetic hydroxyapatite/BaTiO{sub 3} composites with aligned lamellar porous structure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Beilei [Department of Stomatology, Third Xiangya Hospital, Central South University, Changsha, Hunan 410013 (China); Chen, Liangjian, E-mail: jian007040@sina.com [Department of Stomatology, Third Xiangya Hospital, Central South University, Changsha, Hunan 410013 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Shao, Chunsheng [Department of Stomatology, Third Xiangya Hospital, Central South University, Changsha, Hunan 410013 (China); Zhang, Fuqiang; Zhou, Kechao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Cao, Jun [Department of Stomatology, Third Xiangya Hospital, Central South University, Changsha, Hunan 410013 (China); Zhang, Dou, E-mail: dzhang@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2016-04-01

    Osteoblasts growing into bone substitute is an important step of bone regeneration. This study prepared porous hydroxyapatite (HA)/BaTiO{sub 3} piezoelectric composites with porosity of 40%, 50% and 60% by ice-templating method. Effects of HA/BaTiO{sub 3} composites with different porosities, with and without polarizing treatment on adhesion, proliferation and differentiation of osteoblasts were investigated in vitro. Results revealed that cell densities of the porous groups were significantly higher than those of the dense group (p < 0.05), so did the alkaline phosphate (ALP) and bone gla protein (BGP) activities. Porosity of 50% group exhibited higher ALP activity and BGP activity than those of the 40% and 60% groups. Scanning electron microscopy (SEM) observations revealed that osteoblasts adhered and stretched better on porous HA/BaTiO{sub 3} than on the dense one, especially HA/BaTiO{sub 3} with porosity of 50% and 60%. However, there was no significant difference in the cell morphology, cell densities, ALP and BGP activities between the polarized group and the non-polarized group (p > 0.05). The absence of mechanical loading on the polarized samples may account for this. The results indicated that hierarchically porous HA/BaTiO{sub 3} played a favorable part in osteoblasts proliferation, differentiation and adhesion process and is a promising bone substitute material. - Graphical abstract: Aligned porous structure of HA/BaTiO{sub 3} piezoelectric composites prepared by ice-templating method was similar to the lamellar Haversian system in bone tissue. When co-cultured with human osteosarcoma cells (MG63), porous HA/BaTiO{sub 3} composites exhibited remarkable biological activity in promoting proliferation, differentiation and adhesion of MG63 cells. - Highlights: • The aligned porous structure of HA/BaTiO{sub 3} composite was similar to the lamellar Haversian system in bone tissue. • The piezoelectric d{sub 33} coefficient of HA/BaTiO{sub 3} with porosity

  16. Tetravalent one-regular graphs of order 4p2

    DEFF Research Database (Denmark)

    Feng, Yan-Quan; Kutnar, Klavdija; Marusic, Dragan

    2014-01-01

    A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified.......A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified....

  17. Regularity theory for mean-field game systems

    CERN Document Server

    Gomes, Diogo A; Voskanyan, Vardan

    2016-01-01

    Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

  18. Regularity Theory for Mean-Field Game Systems

    KAUST Repository

    Gomes, Diogo A.

    2016-09-14

    Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

  19. Regularity Theory for Mean-Field Game Systems

    KAUST Repository

    Gomes, Diogo A.; Pimentel, Edgard A.; Voskanyan, Vardan K.

    2016-01-01

    Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

  20. Universal regularization prescription for Lovelock AdS gravity

    International Nuclear Information System (INIS)

    Kofinas, Georgios; Olea, Rodrigo

    2007-01-01

    A definite form for the boundary term that produces the finiteness of both the conserved quantities and Euclidean action for any Lovelock gravity with AdS asymptotics is presented. This prescription merely tells even from odd bulk dimensions, regardless the particular theory considered, what is valid even for Einstein-Hilbert and Einstein-Gauss-Bonnet AdS gravity. The boundary term is a given polynomial of the boundary extrinsic and intrinsic curvatures (also referred to as Kounterterms series). Only the coupling constant of the boundary term changes accordingly, such that it always preserves a well-posed variational principle for boundary conditions suitable for asymptotically AdS spaces. The background-independent conserved charges associated to asymptotic symmetries are found. In odd bulk dimensions, this regularization produces a generalized formula for the vacuum energy in Lovelock AdS gravity. The standard entropy for asymptotically AdS black holes is recovered directly from the regularization of the Euclidean action, and not only from the first law of thermodynamics associated to the conserved quantities

  1. Kinetics and mechanism of the pressure-induced lamellar order/disorder transition in phosphatidylethanolamine: a time-resolved X-ray diffraction study.

    Science.gov (United States)

    Mencke, A P; Caffrey, M

    1991-03-05

    By using synchrotron radiation, a movie was made of the X-ray scattering pattern from a biological liquid crystal undergoing a phase transition induced by a pressure jump. The system studied includes the fully hydrated phospholipid dihexadecylphosphatidylethanolamine in the lamellar gel (L beta') phase at a temperature of 68 degrees C and a pressure of 9.7 MPa (1400 psig). Following the rapid release of pressure to atmospheric the L beta' phase transforms slowly into the lamellar liquid crystal (L alpha) phase. The pressure perturbation is applied with the intention of producing a sudden phase disequilibrium followed by monitoring the system as it relaxes to its new equilibrium condition. Remarkably, the proportion of sample in the L alpha phase grows linearly with time, taking 37 s to totally consume the L beta' phase. The time dependencies of radius, peak intensity, and width of the powder diffraction ring of the low-angle (001) lamellar reflections were obtained from the movie by image processing. The concept of an "effective pressure" is introduced to account for the temperature variations that accompany the phase transition and to establish that the observed large transit time is indeed intrinsic to the sample and not due to heat exchange with the environment. The reverse transformation, L alpha to L beta', induced by a sudden jump from atmospheric pressure to 9.7 MPa, is complete in less than 13 s. These measurements represent a new approach for studying the kinetics of lipid phase transitions and for gaining insights into the mechanism of the lamellar order/disorder transition.

  2. [Posterior lamellar keratoplasty with DSEK technique and use of the Tan EndoGlide - short-term results].

    Science.gov (United States)

    Kałuiny, Bartłomiej J; Piotrowiak, Ilona; Sołdańska, Beata; Grzybek, Katarzyna; Czajkowska, Monika; Galas, Małgorzata; Malukiewicz, Grazyna

    2013-01-01

    To present the differences in surgical technique of DSEK (Descemet's Stripping Endothelial Keratoplasty) with the use of Tan EndoGlide (Coronet, UK) and Busin Glide (Moria, FR). Short-term results will also be presented, DSEK was performed in 24 eyes, in 8 cases the surgery was combined with cataract phacoemulsification and lOL implantation. Surgery course and 6 months postoperative results of first 12 eyes performed with the use of Tan EndoGlide were compared with 12 consecutive eyes preformed with Busin Glide. Tan EndoGlide provided much more stable anterior chamber, donor tissue unfolding process was better controlled but the incision was wider incision. Surgically induced mean refractory cylinder 6. months after the surgery was 1.56 - 1.15 Dsph in Tan EndoGlide group and 1.18 +/- 1.10 Dsph in Busin Glide group (P 0.05). Mean CDVA was 0.65+/- 0.27 and 0.63 +/- 0.25, respectively (P>0,05). Statistically significant differences in intra- and post-operative complications between both groups were not found. The Tan EndoGlide used during posterior lamellar keratoplasty with DSEK technique is a good alternative to currently used methods. It provides better stabilization of the anterior chamber, however its use is linked with higher postoperative astigmatism in comparison with Busin Glide. The visual outcomes and endothelial cell loss 6 months after the surgery were similar in both groups.

  3. Visual outcomes after deep anterior lamellar keratoplasty using donor corneas without removal of Descemet membrane and endothelium

    Directory of Open Access Journals (Sweden)

    Tatiana Moura Bastos Prazeres

    Full Text Available ABSTRACT Purpose: The optical quality of the interface after deep anterior lamellar keratoplasty (DALK using the big-bubble technique has been shown to be excellent, leading to results comparable to penetrating keratoplasty. However, there is little in the literature with respect to the controversy surrounding the preparation of the donor cornea. The purpose of this study was to evaluate visual acuity (VA in patients with keratoconus who underwent DALK without removal of the donor graft endothelium. Methods: The records of 90 patients who underwent DALK without the removal of the Descemet membrane (DM and endothelium were retrospectively reviewed. Data collected included uncorrected VA (UCVA and spectacle-corrected VA (SCVA at 7, 30, 180 days, and 1 year postoperatively. Contact lens-corrected visual acuity (CLVA was evaluated after 1 year of the procedure. Results: UCVA was significantly better than preoperative values at 7 days (p<0.001, 30 days (p<0.001, 180 days (p<0.001, and 1 year (p<0.001 after surgery. The 1-year postoperative mean SCVA and CLVA also improved when compared with preoperative SCVA (p<0.001 for both. Conclusions: DALK utilizing donor corneas with attached Descemet membrane and endothelium results in satisfactory VA in patients with keratoconus.

  4. Lamellar granule secretion starts before the establishment of tight junction barrier for paracellular tracers in mammalian epidermis.

    Directory of Open Access Journals (Sweden)

    Akemi Ishida-Yamamoto

    Full Text Available Defects in epidermal barrier function and/or vesicular transport underlie severe skin diseases including ichthyosis and atopic dermatitis. Tight junctions (TJs form a single layered network in simple epithelia. TJs are important for both barrier functions and vesicular transport. Epidermis is stratified epithelia and lamellar granules (LGs are secreted from the stratum granulosum (SG in a sequential manner. Previously, continuous TJs and paracellular permeability barriers were found in the second layer (SG2 of SG in mice, but their fate and correlation with LG secretion have been poorly understood. We studied epidermal TJ-related structures in humans and in mice and found occludin/ZO-1 immunoreactive multilayered networks spanning the first layer of SG (SG1 and SG2. Paracellular penetration tracer passed through some TJs in SG2, but not in SG1. LG secretion into the paracellular tracer positive spaces started below the level of TJs of SG1. Our study suggests that LG-secretion starts before the establishment of TJ barrier in the mammalian epidermis.

  5. A Structural Finite Element Model for Lamellar Unit of Aortic Media Indicates Heterogeneous Stress Field After Collagen Recruitment

    Science.gov (United States)

    Thunes, James R.; Pal, Siladitya; Fortunato, Ronald N.; Phillippi, Julie A.; Gleason, Thomas G.; Vorp, David A.; Maiti, Spandan

    2016-01-01

    Incorporation of collagen structural information into the study of biomechanical behavior of ascending thoracic aortic (ATA) wall tissue should provide better insight into the pathophysiology of ATA. Structurally motivated constitutive models that include fiber dispersion and recruitment can successfully capture overall mechanical response of the arterial wall tissue. However, these models cannot examine local microarchitectural features of the collagen network, such as the effect of fiber disruptions and interaction between fibrous and non-fibrous components, which may influence emergent biomechanical properties of the tissue. Motivated by this need, we developed a finite element based three-dimensional structural model of the lamellar units of the ATA media that directly incorporates the collagen fiber microarchitecture. The fiber architecture was computer generated utilizing network features, namely fiber orientation distribution, intersection density and areal concentration, obtained from image analysis of multiphoton microscopy images taken from human aneurysmal ascending thoracic aortic media specimens with bicuspid aortic valve (BAV) phenotype. Our model reproduces the typical J-shaped constitutive response of the aortic wall tissue. We found that the stress state in the non-fibrous matrix was homogeneous until the collagen fibers were recruited, but became highly heterogeneous after that event. The degree of heterogeneity was dependent upon local network architecture with high stresses observed near disrupted fibers. The magnitude of non-fibrous matrix stress at higher stretch levels was negatively correlated with local fiber density. The localized stress concentrations, elucidated by this model, may be a factor in the degenerative changes in aneurysmal ATA tissue. PMID:27113538

  6. Fabry-Perot magnonic ballistic coherent transport across ultrathin ferromagnetic lamellar bcc Ni nanostructures between Fe leads

    Science.gov (United States)

    Khater, A.; Saim, L.; Tigrine, R.; Ghader, D.

    2018-06-01

    We propose thermodynamically stable systems of ultrathin lamellar bcc Ni nanostructures between bcc Fe leads, sbnd Fe[Ni(n)]Fesbnd , based on the available literature for bcc Ni overlayers on Fe(001) surfaces, and establish the necessary criteria for their structural and ferromagnetic order, for thicknesses n ≤ 6 bcc Ni monatomic layers. The system is globally ferromagnetic. A theoretical model is presented to investigate and understand the ballistic coherent scattering of Fe spin-waves, incident from the leads, at the ferromagnetic bcc Ni nanostructure. The Nisbnd Ni and Nisbnd Fe exchange are computed using the Ising effective field theory (EFT), and the magnetic ground state of the system is constructed in the Heisenberg representation. We compute the spin-wave eigenmodes localized on the bcc Ni nanostructure, using the phase field matching theory (PFMT), illustrating the effects of symmetry breaking on the confinement of localized spin excitations. The reflection and transmission scattering properties of spin-waves incident from the Fe leads, across the embedded Ni nanostructures are investigated within the framework of the same PFMT methodology. A highly refined Fabry-Perot magnonic ballistic coherent transmission spectra is observed for these sbnd Fe[Ni(n)]Fesbnd systems.

  7. Revisiting the relevance of using a constant voltage step to improve electrochemical performances of Li-rich lamellar oxides

    Science.gov (United States)

    Pradon, A.; Caldes, M. T.; Petit, P.-E.; La Fontaine, C.; Elkaim, E.; Tessier, C.; Ouvrard, G.; Dumont, E.

    2018-03-01

    A Li-rich lamellar oxide was cycled at high potential and the relevance of using a constant voltage step (CVS) at the end of the charge, needed for industrial application, was investigated by electrochemical performance, X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Electrochemical studies at 4.7 and 4.5 V with and without CVS showed that capacity and voltage fading occurred mostly when cells operated at high potential. After cycling, 3D-type defects involving transition metals trapped in lithium layer were observed by HRTEM into the electrode bulk. These defects are responsible for the voltage fading. XRD microstrain parameter was used to evaluate defects rate in aged materials subjected to a CVS, showing more 3D-type defects when cycled at 4.7 V than at 4.5 V. The time spent at high potential at the end of the charge as well as the value of the upper potential limit, are both relevant parameters to voltage decay. The use of a CVS at the end of the charge needs at the same time, a reduced upper potential window in order to minimize 3D-type defects occurrence. Unfortunately, this approach is still not sufficient to prevent voltage fading.

  8. Virus-sized self-assembling lamellar complexes between plasmid DNA and cationic micelles promote gene transfer

    Science.gov (United States)

    Pitard, Bruno; Aguerre, Olivier; Airiau, Marc; Lachagès, Anne-Marie; Boukhnikachvili, Tsiala; Byk, Gérardo; Dubertret, Catherine; Herviou, Christian; Scherman, Daniel; Mayaux, Jean-François; Crouzet, Joël

    1997-01-01

    Gene therapy is based on the vectorization of genes to target cells and their subsequent expression. Cationic amphiphile-mediated delivery of plasmid DNA is the nonviral gene transfer method most often used. We examined the supramolecular structure of lipopolyamine/plasmid DNA complexes under various condensing conditions. Plasmid DNA complexation with lipopolyamine micelles whose mean diameter was 5 nm revealed three domains, depending on the lipopolyamine/plasmid DNA ratio. These domains respectively corresponded to negatively, neutrally, and positively charged complexes. Transmission electron microscopy and x-ray scattering experiments on complexes originating from these three domains showed that although their morphology depends on the lipopolyamine/plasmid DNA ratio, their particle structure consists of ordered domains characterized by even spacing of 80 Å, irrespective of the lipid/DNA ratio. The most active lipopolyamine/DNA complexes for gene transfer were positively charged. They were characterized by fully condensed DNA inside spherical particles (diameter: 50 nm) sandwiched between lipid bilayers. These results show that supercoiled plasmid DNA is able to transform lipopolyamine micelles into a supramolecular organization characterized by ordered lamellar domains. PMID:9405626

  9. ATP is stored in lamellar bodies to activate vesicular P2X4 in an autocrine fashion upon exocytosis.

    Science.gov (United States)

    Fois, Giorgio; Winkelmann, Veronika Eva; Bareis, Lara; Staudenmaier, Laura; Hecht, Elena; Ziller, Charlotte; Ehinger, Konstantin; Schymeinsky, Jürgen; Kranz, Christine; Frick, Manfred

    2018-02-05

    Vesicular P2X 4 receptors are known to facilitate secretion and activation of pulmonary surfactant in the alveoli of the lungs. P2X 4 receptors are expressed in the membrane of lamellar bodies (LBs), large secretory lysosomes that store lung surfactant in alveolar type II epithelial cells, and become inserted into the plasma membrane after exocytosis. Subsequent activation of P2X 4 receptors by adenosine triphosphate (ATP) results in local fusion-activated cation entry (FACE), facilitating fusion pore dilation, surfactant secretion, and surfactant activation. Despite the importance of ATP in the alveoli, and hence lung function, the origin of ATP in the alveoli is still elusive. In this study, we demonstrate that ATP is stored within LBs themselves at a concentration of ∼1.9 mM. ATP is loaded into LBs by the vesicular nucleotide transporter but does not activate P2X 4 receptors because of the low intraluminal pH (5.5). However, the rise in intravesicular pH after opening of the exocytic fusion pore results in immediate activation of vesicular P2X 4 by vesicular ATP. Our data suggest a new model in which agonist (ATP) and receptor (P2X 4 ) are located in the same intracellular compartment (LB), protected from premature degradation (ATP) and activation (P2X 4 ), and ideally placed to ensure coordinated and timely receptor activation as soon as fusion occurs to facilitate surfactant secretion. © 2018 Fois et al.

  10. Solvothermal Vapor Annealing of Lamellar Poly(styrene)-block-poly(d,l-lactide) Block Copolymer Thin Films for Directed Self-Assembly Application.

    Science.gov (United States)

    Cummins, Cian; Mokarian-Tabari, Parvaneh; Andreazza, Pascal; Sinturel, Christophe; Morris, Michael A

    2016-03-01

    Solvothermal vapor annealing (STVA) was employed to induce microphase separation in a lamellar forming block copolymer (BCP) thin film containing a readily degradable block. Directed self-assembly of poly(styrene)-block-poly(d,l-lactide) (PS-b-PLA) BCP films using topographically patterned silicon nitride was demonstrated with alignment over macroscopic areas. Interestingly, we observed lamellar patterns aligned parallel as well as perpendicular (perpendicular microdomains to substrate in both cases) to the topography of the graphoepitaxial guiding patterns. PS-b-PLA BCP microphase separated with a high degree of order in an atmosphere of tetrahydrofuran (THF) at an elevated vapor pressure (at approximately 40-60 °C). Grazing incidence small-angle X-ray scattering (GISAXS) measurements of PS-b-PLA films reveal the through-film uniformity of perpendicular microdomains after STVA. Perpendicular lamellar orientation was observed on both hydrophilic and relatively hydrophobic surfaces with a domain spacing (L0) of ∼32.5 nm. The rapid removal of the PLA microdomains is demonstrated using a mild basic solution for the development of a well-defined PS mask template. GISAXS data reveal the through-film uniformity is retained following wet etching. The experimental results in this article demonstrate highly oriented PS-b-PLA microdomains after a short annealing period and facile PLA removal to form porous on-chip etch masks for nanolithography application.

  11. Study of crack propagation mechanisms during Charpy impact toughness tests on both equiaxed and lamellar microstructures of Ti–6Al–4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Buirette, Christophe, E-mail: christophe.buirette@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Huez, Julitte, E-mail: julitte.huez@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Gey, Nathalie, E-mail: Nathalie.gey@univ-lorraine.fr [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR CNRS 7239, Université de Lorraine, Île du Saulcy, 57045 METZ Cedex 1 (France); DAMAS, Laboratory of Excellence on Design of Alloy Metals for Low-Mass Structures, Université de Lorraine (France); Vassel, Alain, E-mail: alain.vassel@titane.asso.fr [Association Française du Titane, 16 quai Ernest Renaud, BP 70515, 44105 Nantes Cedex 4 (France); Andrieu, Eric, E-mail: eric.andrieu@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France)

    2014-11-17

    The impact toughness of two highly textured rolled plates of Ti–6Al–4V alloy with an α equiaxed and an α lamellar microstructures has been investigated. The results show a strong anisotropy of the fracture energy for both materials and underline that a coincidence of the prismatic planes with the shear bands at the notch tip is favorable for higher fracture energies. Moreover, it is pointed out, as it was already done by previous studies, that the α lamellar microstructure presents higher fracture energy than the α equiaxed one. Thanks to electron back scattering diffraction, and tensile tests, local microstructure heterogeneities, called macrozones, have been observed and characterized. Their size depends on microstructure element and is larger for α lamellar microstructure than for the α equiaxed. High strain is localized on the macrozones favorably oriented for prismatic slip with respect to the direction of impact and leads to a particular dimple free zone on the fracture surface. The contribution of these macrozones in the fracture behavior, and more precisely on the crack propagation rate was evaluated; thus the effects of the macroscopic texture and of the microstructure element on the impact toughness are discussed separately.

  12. New Development in Selective Laser Melting of Ti-6Al-4V: A Wider Processing Window for the Achievement of Fully Lamellar α + β Microstructures

    Science.gov (United States)

    Lui, E. W.; Xu, W.; Pateras, A.; Qian, M.; Brandt, M.

    2017-12-01

    Recent progress has shown that Ti-6Al-4V fabricated by selective laser melting (SLM) can achieve a fully lamellar α + β microstructure using 60 µm layer thickness in the as-built state via in situ martensite decomposition by manipulating the processing parameters. The potential to broaden the processing window was explored in this study by increasing the layer thickness to the less commonly used 90 µm. Fully lamellar α + β microstructures were produced in the as-built state using inter-layer times in the range of 1-12 s. Microstructural features such as the α-lath thickness and morphology were sensitive to both build height and inter-layer time. The α-laths produced using the inter-layer time of 1 s were much coarser than those produced with the inter-layer time of 12 s. The fine fully lamellar α + β structure resulted in tensile ductility of 11% and yield strength of 980 MPa. The tensile properties can be further improved by minimizing the presence of process-induced defects.

  13. Using Tikhonov Regularization for Spatial Projections from CSR Regularized Spherical Harmonic GRACE Solutions

    Science.gov (United States)

    Save, H.; Bettadpur, S. V.

    2013-12-01

    It has been demonstrated before that using Tikhonov regularization produces spherical harmonic solutions from GRACE that have very little residual stripes while capturing all the signal observed by GRACE within the noise level. This paper demonstrates a two-step process and uses Tikhonov regularization to remove the residual stripes in the CSR regularized spherical harmonic coefficients when computing the spatial projections. We discuss methods to produce mass anomaly grids that have no stripe features while satisfying the necessary condition of capturing all observed signal within the GRACE noise level.

  14. Entrepreneurial Couples

    DEFF Research Database (Denmark)

    Dahl, Michael S.; Van Praag, Mirjam; Thompson, Peter

    with a selected set of comparable firms and couples. We find evidence that couples often establish a business together because one spouse – most commonly the female – has limited outside opportunities in the labor market. However, the financial benefits for each of the spouses, and especially the female......We study possible motivations for co-entrepenurial couples to start up a joint firm, using a sample of 1,069 Danish couples that established a joint enterprise between 2001 and 2010. We compare their pre-entry characteristics, firm performance and postdissolution private and financial outcomes......, are larger in co-entrepreneurial firms, both during the life of the business and post-dissolution. The start-up of co-entrepreneurial firms seems therefore a sound investment in the human capital of both spouses as well as in the reduction of income inequality in the household. We find no evidence of non...

  15. Entrepreneurial Couples

    DEFF Research Database (Denmark)

    Dahl, Michael S.; Van Praag, Mirjam; Thompson, Peter

    with a selected set of comparable firms and couples. We find evidence that couples often establish a business together because one spouse - most commonly the female - has limited outside opportunities in the labor market. However, the financial benefits for each of the spouses, and especially the female......We study possible motivations for co-entrepenurial couples to start up a joint firm, us-ing a sample of 1,069 Danish couples that established a joint enterprise between 2001 and 2010. We compare their pre-entry characteristics, firm performance and post-dissolution private and financial outcomes......, are larger in co-entrepreneurial firms, both during the life of the business and post-dissolution. The start-up of co-entrepreneurial firms seems therefore a sound in-vestment in the human capital of both spouses as well as in the reduction of income inequality in the household. We find no evidence of non...

  16. Nonideal mixing of phosphatidylserine and phosphatidylcholine in the fluid lamellar phase.

    Science.gov (United States)

    Huang, J; Swanson, J E; Dibble, A R; Hinderliter, A K; Feigenson, G W

    1993-02-01

    The mixing of phosphatidylserine (PS) and phosphatidylcholine (PC) in fluid bilayer model membranes was studied by measuring binding of aqueous Ca2+ ions. The measured [Ca2+]aq was used to derive the activity coefficient for PS, gamma PS, in the lipid mixture. For (16:0, 18:1) PS in binary mixtures with either (16:0, 18:1)PC, (14:1, 14:1)PC, or (18:1, 18:1)PC, gamma PS > 1; i.e., mixing is nonideal, with PS and PC clustered rather than randomly distributed, despite the electrostatic repulsion between PS headgroups. To understand better this mixing behavior, Monte Carlo simulations of the PS/PC distributions were performed, using Kawasaki relaxation. The excess energy was divided into an electrostatic term Uel and one adjustable term including all other nonideal energy contributions, delta Em. Uel was calculated using a discrete charge theory. Kirkwood's coupling parameter method was used to calculate the excess free energy of mixing, delta GEmix, hence In gamma PS,calc. The values of In gamma PS,calc were equalized by adjusting delta Em in order to find the simulated PS/PC distribution that corresponded to the experimental results. We were thus able to compare the smeared charge calculation of [Ca2+]surf with a calculation ("masked evaluation method") that recognized clustering of the negatively charged PS: clustering was found to have a modest effect on [Ca2+]surf, relative to the smeared charge model. Even though both PS and PC tend to cluster, the long-range nature of the electrostatic repulsion reduces the extent of PS clustering at low PS mole fraction compared to PC clustering at an equivalent low PC mole fraction.

  17. Extreme values, regular variation and point processes

    CERN Document Server

    Resnick, Sidney I

    1987-01-01

    Extremes Values, Regular Variation and Point Processes is a readable and efficient account of the fundamental mathematical and stochastic process techniques needed to study the behavior of extreme values of phenomena based on independent and identically distributed random variables and vectors It presents a coherent treatment of the distributional and sample path fundamental properties of extremes and records It emphasizes the core primacy of three topics necessary for understanding extremes the analytical theory of regularly varying functions; the probabilistic theory of point processes and random measures; and the link to asymptotic distribution approximations provided by the theory of weak convergence of probability measures in metric spaces The book is self-contained and requires an introductory measure-theoretic course in probability as a prerequisite Almost all sections have an extensive list of exercises which extend developments in the text, offer alternate approaches, test mastery and provide for enj...

  18. Stream Processing Using Grammars and Regular Expressions

    DEFF Research Database (Denmark)

    Rasmussen, Ulrik Terp

    disambiguation. The first algorithm operates in two passes in a semi-streaming fashion, using a constant amount of working memory and an auxiliary tape storage which is written in the first pass and consumed by the second. The second algorithm is a single-pass and optimally streaming algorithm which outputs...... as much of the parse tree as is semantically possible based on the input prefix read so far, and resorts to buffering as many symbols as is required to resolve the next choice. Optimality is obtained by performing a PSPACE-complete pre-analysis on the regular expression. In the second part we present...... Kleenex, a language for expressing high-performance streaming string processing programs as regular grammars with embedded semantic actions, and its compilation to streaming string transducers with worst-case linear-time performance. Its underlying theory is based on transducer decomposition into oracle...

  19. Describing chaotic attractors: Regular and perpetual points

    Science.gov (United States)

    Dudkowski, Dawid; Prasad, Awadhesh; Kapitaniak, Tomasz

    2018-03-01

    We study the concepts of regular and perpetual points for describing the behavior of chaotic attractors in dynamical systems. The idea of these points, which have been recently introduced to theoretical investigations, is thoroughly discussed and extended into new types of models. We analyze the correlation between regular and perpetual points, as well as their relation with phase space, showing the potential usefulness of both types of points in the qualitative description of co-existing states. The ability of perpetual points in finding attractors is indicated, along with its potential cause. The location of chaotic trajectories and sets of considered points is investigated and the study on the stability of systems is shown. The statistical analysis of the observing desired states is performed. We focus on various types of dynamical systems, i.e., chaotic flows with self-excited and hidden attractors, forced mechanical models, and semiconductor superlattices, exhibiting the universality of appearance of the observed patterns and relations.

  20. Chaos regularization of quantum tunneling rates

    International Nuclear Information System (INIS)

    Pecora, Louis M.; Wu Dongho; Lee, Hoshik; Antonsen, Thomas; Lee, Ming-Jer; Ott, Edward

    2011-01-01

    Quantum tunneling rates through a barrier separating two-dimensional, symmetric, double-well potentials are shown to depend on the classical dynamics of the billiard trajectories in each well and, hence, on the shape of the wells. For shapes that lead to regular (integrable) classical dynamics the tunneling rates fluctuate greatly with eigenenergies of the states sometimes by over two orders of magnitude. Contrarily, shapes that lead to completely chaotic trajectories lead to tunneling rates whose fluctuations are greatly reduced, a phenomenon we call regularization of tunneling rates. We show that a random-plane-wave theory of tunneling accounts for the mean tunneling rates and the small fluctuation variances for the chaotic systems.

  1. Least square regularized regression in sum space.

    Science.gov (United States)

    Xu, Yong-Li; Chen, Di-Rong; Li, Han-Xiong; Liu, Lu

    2013-04-01

    This paper proposes a least square regularized regression algorithm in sum space of reproducing kernel Hilbert spaces (RKHSs) for nonflat function approximation, and obtains the solution of the algorithm by solving a system of linear equations. This algorithm can approximate the low- and high-frequency component of the target function with large and small scale kernels, respectively. The convergence and learning rate are analyzed. We measure the complexity of the sum space by its covering number and demonstrate that the covering number can be bounded by the product of the covering numbers of basic RKHSs. For sum space of RKHSs with Gaussian kernels, by choosing appropriate parameters, we tradeoff the sample error and regularization error, and obtain a polynomial learning rate, which is better than that in any single RKHS. The utility of this method is illustrated with two simulated data sets and five real-life databases.

  2. Contour Propagation With Riemannian Elasticity Regularization

    DEFF Research Database (Denmark)

    Bjerre, Troels; Hansen, Mads Fogtmann; Sapru, W.

    2011-01-01

    Purpose/Objective(s): Adaptive techniques allow for correction of spatial changes during the time course of the fractionated radiotherapy. Spatial changes include tumor shrinkage and weight loss, causing tissue deformation and residual positional errors even after translational and rotational image...... the planning CT onto the rescans and correcting to reflect actual anatomical changes. For deformable registration, a free-form, multi-level, B-spline deformation model with Riemannian elasticity, penalizing non-rigid local deformations, and volumetric changes, was used. Regularization parameters was defined...... on the original delineation and tissue deformation in the time course between scans form a better starting point than rigid propagation. There was no significant difference of locally and globally defined regularization. The method used in the present study suggests that deformed contours need to be reviewed...

  3. Thin accretion disk around regular black hole

    Directory of Open Access Journals (Sweden)

    QIU Tianqi

    2014-08-01

    Full Text Available The Penrose′s cosmic censorship conjecture says that naked singularities do not exist in nature.So,it seems reasonable to further conjecture that not even a singularity exists in nature.In this paper,a regular black hole without singularity is studied in detail,especially on its thin accretion disk,energy flux,radiation temperature and accretion efficiency.It is found that the interaction of regular black hole is stronger than that of the Schwarzschild black hole. Furthermore,the thin accretion will be more efficiency to lost energy while the mass of black hole decreased. These particular properties may be used to distinguish between black holes.

  4. Convex nonnegative matrix factorization with manifold regularization.

    Science.gov (United States)

    Hu, Wenjun; Choi, Kup-Sze; Wang, Peiliang; Jiang, Yunliang; Wang, Shitong

    2015-03-01

    Nonnegative Matrix Factorization (NMF) has been extensively applied in many areas, including computer vision, pattern recognition, text mining, and signal processing. However, nonnegative entries are usually required for the data matrix in NMF, which limits its application. Besides, while the basis and encoding vectors obtained by NMF can represent the original data in low dimension, the representations do not always reflect the intrinsic geometric structure embedded in the data. Motivated by manifold learning and Convex NMF (CNMF), we propose a novel matrix factorization method called Graph Regularized and Convex Nonnegative Matrix Factorization (GCNMF) by introducing a graph regularized term into CNMF. The proposed matrix factorization technique not only inherits the intrinsic low-dimensional manifold structure, but also allows the processing of mixed-sign data matrix. Clustering experiments on nonnegative and mixed-sign real-world data sets are conducted to demonstrate the effectiveness of the proposed method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The geometric β-function in curved space-time under operator regularization

    Energy Technology Data Exchange (ETDEWEB)

    Agarwala, Susama [Mathematical Institute, Oxford University, Oxford OX2 6GG (United Kingdom)

    2015-06-15

    In this paper, I compare the generators of the renormalization group flow, or the geometric β-functions, for dimensional regularization and operator regularization. I then extend the analysis to show that the geometric β-function for a scalar field theory on a closed compact Riemannian manifold is defined on the entire manifold. I then extend the analysis to find the generator of the renormalization group flow to conformally coupled scalar-field theories on the same manifolds. The geometric β-function in this case is not defined.

  6. The geometric β-function in curved space-time under operator regularization

    International Nuclear Information System (INIS)

    Agarwala, Susama

    2015-01-01

    In this paper, I compare the generators of the renormalization group flow, or the geometric β-functions, for dimensional regularization and operator regularization. I then extend the analysis to show that the geometric β-function for a scalar field theory on a closed compact Riemannian manifold is defined on the entire manifold. I then extend the analysis to find the generator of the renormalization group flow to conformally coupled scalar-field theories on the same manifolds. The geometric β-function in this case is not defined

  7. A short proof of increased parabolic regularity

    Directory of Open Access Journals (Sweden)

    Stephen Pankavich

    2015-08-01

    Full Text Available We present a short proof of the increased regularity obtained by solutions to uniformly parabolic partial differential equations. Though this setting is fairly introductory, our new method of proof, which uses a priori estimates and an inductive method, can be extended to prove analogous results for problems with time-dependent coefficients, advection-diffusion or reaction diffusion equations, and nonlinear PDEs even when other tools, such as semigroup methods or the use of explicit fundamental solutions, are unavailable.

  8. Regular black hole in three dimensions

    OpenAIRE

    Myung, Yun Soo; Yoon, Myungseok

    2008-01-01

    We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

  9. Sparse regularization for force identification using dictionaries

    Science.gov (United States)

    Qiao, Baijie; Zhang, Xingwu; Wang, Chenxi; Zhang, Hang; Chen, Xuefeng

    2016-04-01

    The classical function expansion method based on minimizing l2-norm of the response residual employs various basis functions to represent the unknown force. Its difficulty lies in determining the optimum number of basis functions. Considering the sparsity of force in the time domain or in other basis space, we develop a general sparse regularization method based on minimizing l1-norm of the coefficient vector of basis functions. The number of basis functions is adaptively determined by minimizing the number of nonzero components in the coefficient vector during the sparse regularization process. First, according to the profile of the unknown force, the dictionary composed of basis functions is determined. Second, a sparsity convex optimization model for force identification is constructed. Third, given the transfer function and the operational response, Sparse reconstruction by separable approximation (SpaRSA) is developed to solve the sparse regularization problem of force identification. Finally, experiments including identification of impact and harmonic forces are conducted on a cantilever thin plate structure to illustrate the effectiveness and applicability of SpaRSA. Besides the Dirac dictionary, other three sparse dictionaries including Db6 wavelets, Sym4 wavelets and cubic B-spline functions can also accurately identify both the single and double impact forces from highly noisy responses in a sparse representation frame. The discrete cosine functions can also successfully reconstruct the harmonic forces including the sinusoidal, square and triangular forces. Conversely, the traditional Tikhonov regularization method with the L-curve criterion fails to identify both the impact and harmonic forces in these cases.

  10. Analytic stochastic regularization and gauge theories

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Lima-Santos, A.

    1987-04-01

    We prove that analytic stochatic regularization braks gauge invariance. This is done by an explicit one loop calculation of the two three and four point vertex functions of the gluon field in scalar chromodynamics, which turns out not to be geuge invariant. We analyse the counter term structure, Langevin equations and the construction of composite operators in the general framework of stochastic quantization. (author) [pt

  11. Preconditioners for regularized saddle point matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2011-01-01

    Roč. 19, č. 2 (2011), s. 91-112 ISSN 1570-2820 Institutional research plan: CEZ:AV0Z30860518 Keywords : saddle point matrices * preconditioning * regularization * eigenvalue clustering Subject RIV: BA - General Mathematics Impact factor: 0.533, year: 2011 http://www.degruyter.com/view/j/jnma.2011.19.issue-2/jnum.2011.005/jnum.2011.005. xml

  12. Analytic stochastic regularization: gauge and supersymmetry theories

    International Nuclear Information System (INIS)

    Abdalla, M.C.B.

    1988-01-01

    Analytic stochastic regularization for gauge and supersymmetric theories is considered. Gauge invariance in spinor and scalar QCD is verified to brak fown by an explicit one loop computation of the two, theree and four point vertex function of the gluon field. As a result, non gauge invariant counterterms must be added. However, in the supersymmetric multiplets there is a cancellation rendering the counterterms gauge invariant. The calculation is considered at one loop order. (author) [pt

  13. Regularized forecasting of chaotic dynamical systems

    International Nuclear Information System (INIS)

    Bollt, Erik M.

    2017-01-01

    While local models of dynamical systems have been highly successful in terms of using extensive data sets observing even a chaotic dynamical system to produce useful forecasts, there is a typical problem as follows. Specifically, with k-near neighbors, kNN method, local observations occur due to recurrences in a chaotic system, and this allows for local models to be built by regression to low dimensional polynomial approximations of the underlying system estimating a Taylor series. This has been a popular approach, particularly in context of scalar data observations which have been represented by time-delay embedding methods. However such local models can generally allow for spatial discontinuities of forecasts when considered globally, meaning jumps in predictions because the collected near neighbors vary from point to point. The source of these discontinuities is generally that the set of near neighbors varies discontinuously with respect to the position of the sample point, and so therefore does the model built from the near neighbors. It is possible to utilize local information inferred from near neighbors as usual but at the same time to impose a degree of regularity on a global scale. We present here a new global perspective extending the general local modeling concept. In so doing, then we proceed to show how this perspective allows us to impose prior presumed regularity into the model, by involving the Tikhonov regularity theory, since this classic perspective of optimization in ill-posed problems naturally balances fitting an objective with some prior assumed form of the result, such as continuity or derivative regularity for example. This all reduces to matrix manipulations which we demonstrate on a simple data set, with the implication that it may find much broader context.

  14. Minimal length uncertainty relation and ultraviolet regularization

    Science.gov (United States)

    Kempf, Achim; Mangano, Gianpiero

    1997-06-01

    Studies in string theory and quantum gravity suggest the existence of a finite lower limit Δx0 to the possible resolution of distances, at the latest on the scale of the Planck length of 10-35 m. Within the framework of the Euclidean path integral we explicitly show ultraviolet regularization in field theory through this short distance structure. Both rotation and translation invariance can be preserved. An example is studied in detail.

  15. Regularity and chaos in cavity QED

    International Nuclear Information System (INIS)

    Bastarrachea-Magnani, Miguel Angel; López-del-Carpio, Baldemar; Chávez-Carlos, Jorge; Lerma-Hernández, Sergio; Hirsch, Jorge G

    2017-01-01

    The interaction of a quantized electromagnetic field in a cavity with a set of two-level atoms inside it can be described with algebraic Hamiltonians of increasing complexity, from the Rabi to the Dicke models. Their algebraic character allows, through the use of coherent states, a semiclassical description in phase space, where the non-integrable Dicke model has regions associated with regular and chaotic motion. The appearance of classical chaos can be quantified calculating the largest Lyapunov exponent over the whole available phase space for a given energy. In the quantum regime, employing efficient diagonalization techniques, we are able to perform a detailed quantitative study of the regular and chaotic regions, where the quantum participation ratio (P R ) of coherent states on the eigenenergy basis plays a role equivalent to the Lyapunov exponent. It is noted that, in the thermodynamic limit, dividing the participation ratio by the number of atoms leads to a positive value in chaotic regions, while it tends to zero in the regular ones. (paper)

  16. Solution path for manifold regularized semisupervised classification.

    Science.gov (United States)

    Wang, Gang; Wang, Fei; Chen, Tao; Yeung, Dit-Yan; Lochovsky, Frederick H

    2012-04-01

    Traditional learning algorithms use only labeled data for training. However, labeled examples are often difficult or time consuming to obtain since they require substantial human labeling efforts. On the other hand, unlabeled data are often relatively easy to collect. Semisupervised learning addresses this problem by using large quantities of unlabeled data with labeled data to build better learning algorithms. In this paper, we use the manifold regularization approach to formulate the semisupervised learning problem where a regularization framework which balances a tradeoff between loss and penalty is established. We investigate different implementations of the loss function and identify the methods which have the least computational expense. The regularization hyperparameter, which determines the balance between loss and penalty, is crucial to model selection. Accordingly, we derive an algorithm that can fit the entire path of solutions for every value of the hyperparameter. Its computational complexity after preprocessing is quadratic only in the number of labeled examples rather than the total number of labeled and unlabeled examples.

  17. Regularizations: different recipes for identical situations

    International Nuclear Information System (INIS)

    Gambin, E.; Lobo, C.O.; Battistel, O.A.

    2004-03-01

    We present a discussion where the choice of the regularization procedure and the routing for the internal lines momenta are put at the same level of arbitrariness in the analysis of Ward identities involving simple and well-known problems in QFT. They are the complex self-interacting scalar field and two simple models where the SVV and AVV process are pertinent. We show that, in all these problems, the conditions to symmetry relations preservation are put in terms of the same combination of divergent Feynman integrals, which are evaluated in the context of a very general calculational strategy, concerning the manipulations and calculations involving divergences. Within the adopted strategy, all the arbitrariness intrinsic to the problem are still maintained in the final results and, consequently, a perfect map can be obtained with the corresponding results of the traditional regularization techniques. We show that, when we require an universal interpretation for the arbitrariness involved, in order to get consistency with all stated physical constraints, a strong condition is imposed for regularizations which automatically eliminates the ambiguities associated to the routing of the internal lines momenta of loops. The conclusion is clean and sound: the association between ambiguities and unavoidable symmetry violations in Ward identities cannot be maintained if an unique recipe is required for identical situations in the evaluation of divergent physical amplitudes. (author)

  18. Representing and computing regular languages on massively parallel networks

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.I.; O' Sullivan, J.A. (Electronic Systems and Research Lab., of Electrical Engineering, Washington Univ., St. Louis, MO (US)); Boysam, B. (Dept. of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Inst., Troy, NY (US)); Smith, K.R. (Dept. of Electrical Engineering, Southern Illinois Univ., Edwardsville, IL (US))

    1991-01-01

    This paper proposes a general method for incorporating rule-based constraints corresponding to regular languages into stochastic inference problems, thereby allowing for a unified representation of stochastic and syntactic pattern constraints. The authors' approach first established the formal connection of rules to Chomsky grammars, and generalizes the original work of Shannon on the encoding of rule-based channel sequences to Markov chains of maximum entropy. This maximum entropy probabilistic view leads to Gibb's representations with potentials which have their number of minima growing at precisely the exponential rate that the language of deterministically constrained sequences grow. These representations are coupled to stochastic diffusion algorithms, which sample the language-constrained sequences by visiting the energy minima according to the underlying Gibbs' probability law. The coupling to stochastic search methods yields the all-important practical result that fully parallel stochastic cellular automata may be derived to generate samples from the rule-based constraint sets. The production rules and neighborhood state structure of the language of sequences directly determines the necessary connection structures of the required parallel computing surface. Representations of this type have been mapped to the DAP-510 massively-parallel processor consisting of 1024 mesh-connected bit-serial processing elements for performing automated segmentation of electron-micrograph images.

  19. Bypassing the Limits of Ll Regularization: Convex Sparse Signal Processing Using Non-Convex Regularization

    Science.gov (United States)

    Parekh, Ankit

    Sparsity has become the basis of some important signal processing methods over the last ten years. Many signal processing problems (e.g., denoising, deconvolution, non-linear component analysis) can be expressed as inverse problems. Sparsity is invoked through the formulation of an inverse problem with suitably designed regularization terms. The regularization terms alone encode sparsity into the problem formulation. Often, the ℓ1 norm is used to induce sparsity, so much so that ℓ1 regularization is considered to be `modern least-squares'. The use of ℓ1 norm, as a sparsity-inducing regularizer, leads to a convex optimization problem, which has several benefits: the absence of extraneous local minima, well developed theory of globally convergent algorithms, even for large-scale problems. Convex regularization via the ℓ1 norm, however, tends to under-estimate the non-zero values of sparse signals. In order to estimate the non-zero values more accurately, non-convex regularization is often favored over convex regularization. However, non-convex regularization generally leads to non-convex optimization, which suffers from numerous issues: convergence may be guaranteed to only a stationary point, problem specific parameters may be difficult to set, and the solution is sensitive to the initialization of the algorithm. The first part of this thesis is aimed toward combining the benefits of non-convex regularization and convex optimization to estimate sparse signals more effectively. To this end, we propose to use parameterized non-convex regularizers with designated non-convexity and provide a range for the non-convex parameter so as to ensure that the objective function is strictly convex. By ensuring convexity of the objective function (sum of data-fidelity and non-convex regularizer), we can make use of a wide variety of convex optimization algorithms to obtain the unique global minimum reliably. The second part of this thesis proposes a non-linear signal

  20. Sparsity regularization for parameter identification problems

    International Nuclear Information System (INIS)

    Jin, Bangti; Maass, Peter

    2012-01-01

    The investigation of regularization schemes with sparsity promoting penalty terms has been one of the dominant topics in the field of inverse problems over the last years, and Tikhonov functionals with ℓ p -penalty terms for 1 ⩽ p ⩽ 2 have been studied extensively. The first investigations focused on regularization properties of the minimizers of such functionals with linear operators and on iteration schemes for approximating the minimizers. These results were quickly transferred to nonlinear operator equations, including nonsmooth operators and more general function space settings. The latest results on regularization properties additionally assume a sparse representation of the true solution as well as generalized source conditions, which yield some surprising and optimal convergence rates. The regularization theory with ℓ p sparsity constraints is relatively complete in this setting; see the first part of this review. In contrast, the development of efficient numerical schemes for approximating minimizers of Tikhonov functionals with sparsity constraints for nonlinear operators is still ongoing. The basic iterated soft shrinkage approach has been extended in several directions and semi-smooth Newton methods are becoming applicable in this field. In particular, the extension to more general non-convex, non-differentiable functionals by variational principles leads to a variety of generalized iteration schemes. We focus on such iteration schemes in the second part of this review. A major part of this survey is devoted to applying sparsity constrained regularization techniques to parameter identification problems for partial differential equations, which we regard as the prototypical setting for nonlinear inverse problems. Parameter identification problems exhibit different levels of complexity and we aim at characterizing a hierarchy of such problems. The operator defining these inverse problems is the parameter-to-state mapping. We first summarize some

  1. Learning Sparse Visual Representations with Leaky Capped Norm Regularizers

    OpenAIRE

    Wangni, Jianqiao; Lin, Dahua

    2017-01-01

    Sparsity inducing regularization is an important part for learning over-complete visual representations. Despite the popularity of $\\ell_1$ regularization, in this paper, we investigate the usage of non-convex regularizations in this problem. Our contribution consists of three parts. First, we propose the leaky capped norm regularization (LCNR), which allows model weights below a certain threshold to be regularized more strongly as opposed to those above, therefore imposes strong sparsity and...

  2. Temporal regularity of the environment drives time perception

    OpenAIRE

    van Rijn, H; Rhodes, D; Di Luca, M

    2016-01-01

    It’s reasonable to assume that a regularly paced sequence should be perceived as regular, but here we show that perceived regularity depends on the context in which the sequence is embedded. We presented one group of participants with perceptually regularly paced sequences, and another group of participants with mostly irregularly paced sequences (75% irregular, 25% regular). The timing of the final stimulus in each sequence could be var- ied. In one experiment, we asked whether the last stim...

  3. Regular-, irregular-, and pseudo-character processing in Chinese: The regularity effect in normal adult readers

    Directory of Open Access Journals (Sweden)

    Dustin Kai Yan Lau

    2014-03-01

    Full Text Available Background Unlike alphabetic languages, Chinese uses a logographic script. However, the pronunciation of many character’s phonetic radical has the same pronunciation as the character as a whole. These are considered regular characters and can be read through a lexical non-semantic route (Weekes & Chen, 1999. Pseudocharacters are another way to study this non-semantic route. A pseudocharacter is the combination of existing semantic and phonetic radicals in their legal positions resulting in a non-existing character (Ho, Chan, Chung, Lee, & Tsang, 2007. Pseudocharacters can be pronounced by direct derivation from the sound of its phonetic radical. Conversely, if the pronunciation of a character does not follow that of the phonetic radical, it is considered as irregular and can only be correctly read through the lexical-semantic route. The aim of the current investigation was to examine reading aloud in normal adults. We hypothesized that the regularity effect, previously described for alphabetical scripts and acquired dyslexic patients of Chinese (Weekes & Chen, 1999; Wu, Liu, Sun, Chromik, & Zhang, 2014, would also be present in normal adult Chinese readers. Method Participants. Thirty (50% female native Hong Kong Cantonese speakers with a mean age of 19.6 years and a mean education of 12.9 years. Stimuli. Sixty regular-, 60 irregular-, and 60 pseudo-characters (with at least 75% of name agreement in Chinese were matched by initial phoneme, number of strokes and family size. Additionally, regular- and irregular-characters were matched by frequency (low and consistency. Procedure. Each participant was asked to read aloud the stimuli presented on a laptop using the DMDX software. The order of stimuli presentation was randomized. Data analysis. ANOVAs were carried out by participants and items with RTs and errors as dependent variables and type of stimuli (regular-, irregular- and pseudo-character as repeated measures (F1 or between subject

  4. Convergence and fluctuations of Regularized Tyler estimators

    KAUST Repository

    Kammoun, Abla; Couillet, Romain; Pascal, Frederic; Alouini, Mohamed-Slim

    2015-01-01

    This article studies the behavior of regularized Tyler estimators (RTEs) of scatter matrices. The key advantages of these estimators are twofold. First, they guarantee by construction a good conditioning of the estimate and second, being a derivative of robust Tyler estimators, they inherit their robustness properties, notably their resilience to the presence of outliers. Nevertheless, one major problem that poses the use of RTEs in practice is represented by the question of setting the regularization parameter p. While a high value of p is likely to push all the eigenvalues away from zero, it comes at the cost of a larger bias with respect to the population covariance matrix. A deep understanding of the statistics of RTEs is essential to come up with appropriate choices for the regularization parameter. This is not an easy task and might be out of reach, unless one considers asymptotic regimes wherein the number of observations n and/or their size N increase together. First asymptotic results have recently been obtained under the assumption that N and n are large and commensurable. Interestingly, no results concerning the regime of n going to infinity with N fixed exist, even though the investigation of this assumption has usually predated the analysis of the most difficult N and n large case. This motivates our work. In particular, we prove in the present paper that the RTEs converge to a deterministic matrix when n → ∞ with N fixed, which is expressed as a function of the theoretical covariance matrix. We also derive the fluctuations of the RTEs around this deterministic matrix and establish that these fluctuations converge in distribution to a multivariate Gaussian distribution with zero mean and a covariance depending on the population covariance and the parameter.

  5. Convergence and fluctuations of Regularized Tyler estimators

    KAUST Repository

    Kammoun, Abla

    2015-10-26

    This article studies the behavior of regularized Tyler estimators (RTEs) of scatter matrices. The key advantages of these estimators are twofold. First, they guarantee by construction a good conditioning of the estimate and second, being a derivative of robust Tyler estimators, they inherit their robustness properties, notably their resilience to the presence of outliers. Nevertheless, one major problem that poses the use of RTEs in practice is represented by the question of setting the regularization parameter p. While a high value of p is likely to push all the eigenvalues away from zero, it comes at the cost of a larger bias with respect to the population covariance matrix. A deep understanding of the statistics of RTEs is essential to come up with appropriate choices for the regularization parameter. This is not an easy task and might be out of reach, unless one considers asymptotic regimes wherein the number of observations n and/or their size N increase together. First asymptotic results have recently been obtained under the assumption that N and n are large and commensurable. Interestingly, no results concerning the regime of n going to infinity with N fixed exist, even though the investigation of this assumption has usually predated the analysis of the most difficult N and n large case. This motivates our work. In particular, we prove in the present paper that the RTEs converge to a deterministic matrix when n → ∞ with N fixed, which is expressed as a function of the theoretical covariance matrix. We also derive the fluctuations of the RTEs around this deterministic matrix and establish that these fluctuations converge in distribution to a multivariate Gaussian distribution with zero mean and a covariance depending on the population covariance and the parameter.

  6. Low-pH-Induced Lamellar to Bicontinuous Primitive Cubic Phase Transition in Dioleoylphosphatidylserine/Monoolein Membranes.

    Science.gov (United States)

    Oka, Toshihiko; Hasan, Moynul; Islam, Md Zahidul; Moniruzzaman, Md; Yamazaki, Masahito

    2017-10-31

    Electrostatic interactions (EIs) play important roles in the structure and stability of inverse bicontinuous cubic (Q II ) phases of lipid membranes. We examined the effect of pH on the phase of dioleoylphosphatidylserine (DOPS)/monoolein (MO) membranes at low ionic strengths using small-angle X-ray scattering (SAXS). We found that the phase transitions from lamellar liquid-crystalline (L α ) to primitive cubic (Q II P ) phases in DOPS/MO (2/8 molar ratio) membranes occurred in buffers containing 50 mM NaCl at and below the final pH of 2.75 as the pH of the membrane suspension was decreased from a neutral value. The kinetic pathway of this transition was revealed using time-resolved SAXS with a stopped-flow apparatus. The first step is a rapid transition from the L α phase to the hexagonal II (H II ) phase, and the second step is a slow transition from the H II phase to the Q II P phase. We determined the rate constants of the first step, k 1 , and of the second step, k 2 , by analyzing the time course of SAXS intensities quantitatively. The k 1 value increased with temperature. The analysis of this result provided the values of its apparent activation energy, which were constant over temperature but increased with pH. This can be explained by an EI effect on the free energy of the transition state. In contrast, the k 2 value decreased with temperature, indicating that the true activation energy increased with temperature. These experimental results were analyzed using the theory of the activation energy of phase transitions of lipid membranes when the free energy of the transition state depends on temperature. On the basis of these results, we discussed the mechanism of this phase transition.

  7. Zero-charged catanionic lamellar liquid crystals doped with fullerene C60 for potential applications in tribology.

    Science.gov (United States)

    Chen, Mengjun; Liu, Baoyong; Wang, Xiaolin; Fu, Yanxu; Hao, Jingcheng; Li, Hongguang

    2017-09-20

    The formation of lamellar liquid crystals (LLCs) has been demonstrated in a few salt-free catanionic surfactant systems and their properties have been well documented. However, examples of their combination with other materials are relatively rare. Herein, a salt-free zero-charged catanionic surfactant with low chain melting temperature was prepared by mixing equimolar tetradecyltrimethylammonium oxide (TTAOH) and oleic acid (OA) in water, and its concentration-dependent aggregate transition was investigated. In the dilute region (c TTAO ≤ 5 wt%), fluorescence microscopy observations revealed the formation of vesicles (the L αv phase). Further increasing c TTAO induced a transition from the L αv phase to LLCs via a region where vesicles and lamellae coexist. With ordered hydrophobic domains, the LLCs can be used as hosts for the doping of fullerene C 60 (refers to C 60 hereafter) with the highest C 60 /TTAO weight ratio of 0.04. The doping of C 60 effectively improves the viscoelasticity of the LLCs confirmed by rheological characterization while only slight modifications on their matrixes have been detected using small angle X-ray scattering measurements. The LLC/C 60 hybrids with c TTAO = 80 wt% were then subjected to tribological measurements, and an obvious reduction in their friction coefficients and wear volumes was observed. The C 60 /TTAO weight ratio at which the best tribological performance appears was determined to be 0.01. Our results indicate that the combination of C 60 and catanionic LLCs could lead to the appearance of a new generation of environmentally-benign lubricants.

  8. The influence of a silica pillar in lamellar tetratitanate for selective catalytic reduction of NOx using NH3

    International Nuclear Information System (INIS)

    Nogueira da Cunha, Beatriz; Gonçalves, Alécia Maria; Gomes da Silveira, Rafael; Urquieta-González, Ernesto A.; Magalhães Nunes, Liliane

    2015-01-01

    Highlights: • Potassium ions significantly affected the SCR. • The introduction of silica in the catalyst promotes the NH 3 -SCR reaction. • The catalysts activities were not significantly influenced by SO 2 addition. - Abstract: Silica-pillared layered titanate (SiO 2 –Ti 4 O 9 ) was prepared by intercalating organosilanes into the interlayers of a layered K 2 Ti 4 O 9 followed by calcination at 500 °C. The lamellar titanates produced were used as a support to prepare vanadium catalysts (1 and 2 wt%) through wet impregnation for selective catalytic reduction (SCR) of NO. The catalysts were characterized using nitrogen adsorption (BET), X-ray diffraction (XRD), temperature programmed reduction (H 2 -TPR), nuclear magnetic resonance ( 29 Si NMR), and infrared spectroscopy (FT-IR). Reduction of NO by NH 3 was studied in a fixed-bed reactor packed with the catalysts and fed a mixture comprising 1% NH 3 , 1% NO, 10% O 2 , and 34 ppm SO 2 (when used) in helium. The results demonstrate that activity is correlated with the support, i.e., with acidic strength of catalysts. The potassium in the support, K 2 Ti 4 O 9 , significantly affected the reaction and level of vanadium species reduction. The catalyst (1VSiT) with 1 wt% vanadium impregnated on the SiO 2 –Ti 4 O 9 support reduced ∼80% of the NO. Approximately the same conversion rate was generated on the catalyst (2VSiT) with 2 wt% vanadium using the same support. The increased NH 3 adsorption demonstrate that introduction of silica in the catalyst promotes the NH 3 -SCR reaction. More importantly, 2VSiT and 1VSiT were strongly resistant to SO 2 poisoning

  9. Modified big-bubble technique compared to manual dissection deep anterior lamellar keratoplasty in the treatment of keratoconus.

    Science.gov (United States)

    Knutsson, Karl Anders; Rama, Paolo; Paganoni, Giorgio

    2015-08-01

    To evaluate the clinical findings and results of manual dissection deep anterior lamellar keratoplasty (DALK) compared to a modified big-bubble DALK technique in eyes affected by keratoconus. Sixty eyes of 60 patients with keratoconus were treated with one of the two surgical techniques manual DALK (n = 30); big-bubble DALK (n = 30). The main outcomes measured were visual acuity, corneal topographic parameters, thickness of residual stroma and endothelial cell density (ECD). Patients were examined postoperatively at 1 month, 6 months, 1 year and 1 month after suture removal. Final best spectacle-corrected visual acuity (BSCVA) measured 1 month after suture removal was 0.11 ± 0.08 LogMAR in the big-bubble group compared to 0.13 ± 0.08 in the manual DALK group (p = 0.227). In patients treated with the big-bubble technique without complications (Descemet's membrane completely bared), the stromal residue was not measureable. Mean stromal residual thickness in the manual DALK group was 30.50 ± 27.60 μm. Data analysis of the manual DALK group demonstrated a significant correlation between BSCVA and residual stromal thickness; lower residual stromal thickness correlated with better BSCVA values (Spearman ρ = 0.509, p = 0.018). Postoperative ECD was similar in both groups at all intervals, with no statistically significant differences. In both groups, ECD loss was only significant during the 1- to 6-month interval (p = 0.001 and p big-bubble DALK and manual DALK groups, respectively). Manual DALK provides comparable results to big-bubble DALK. Big-bubble DALK permits faster visual recovery and is a surgical technique, which can be easily converted to manual DALK in cases of unsuccessful 'big-bubble' formation. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. Safety and efficacy of nano lamellar TiN coatings on nitinol atrial septal defect occluders in vivo

    International Nuclear Information System (INIS)

    Zhang, Zhi xiong; Fu, Bu fang; Zhang, De yuan; Zhang, Zhi wei; Cheng, Yan; Sheng, Li yuan; Lai, Chen; Xi, Ting fei

    2013-01-01

    Atrial septal defect (ASD) occlusion devices made of nickel–titanium (NiTi) have a major shortcoming in that they release nickel into the body. We modified NiTi occluders using Arc Ion Plating technology. Nano lamellar titanium–nitrogen (TiN) coatings were formed on the surfaces of the occluders. The safety and efficacy of the modified NiTi occluders were evaluated in animal model. The results showed that 38 out of 39 rams (97%) survived at the end of the experiment. Fibrous capsules formed on the surfaces of the devices. Gradual endothelialization took place through the attachment of endothelial progenitor cells from the blood and the migration of endothelial cells from adjacent endocardium. The neo-endocardium formed more quickly in the coated group than in the uncoated group, as indicated by the evaluation of the six month study group. After TiN coating, there was no significant difference in endothelial cell cycle. TiN coating significantly reduced the release of nickel in both in vivo and in vitro indicating an improved biocompatibility of the nitinol ASD occluders. Superior and modified ASD occluders may provide a good choice for people with nickel allergies after sFDA registration, which is expected in one to two years. - Highlights: ► The nano lamella TiN coating did not change the shape-memory behavior and flexibility of the nitinol occluder. ► Nano lamella TiN coating modifications significantly reduced nickel release from nitinol ASD occluder. ► The new ASD occluder was found to be superior to nitinol ASD occluder with respect to both safety and efficacy

  11. The Influence of Lamellar Orientation on Corneal Material Behavior: Biomechanical and Structural Changes in an Avian Corneal Disorder

    Science.gov (United States)

    Elsheikh, Ahmed; Kassem, Wael; Kamma-Lorger, Christina S.; Hocking, Paul M.; White, Nick; Inglehearn, Chris F.; Ali, Manir; Meek, Keith M.

    2011-01-01

    Purpose. Retinopathy, globe enlarged (RGE) is an inherited genetic disease of chickens with a corneal phenotype characterized by loss of tissue curvature and changes in peripheral collagen fibril alignment. This study aimed to characterize the material behavior of normal and RGE chicken corneas under inflation and compare this with new spatial- and depth-resolved microstructural information to investigate how stromal fibril architecture determines corneal behavior under intraocular pressure (IOP). Methods. Six RGE chicken corneas and six age-matched normal controls were tested using trephinate inflation and their stress-strain behavior determined as a function of posterior pressure. Second harmonic generation mulitphoton microscopy was used to compare the in-plane appearance and degree of through-plane interlacing of collagen lamellae between normal and mutant corneas. Results. RGE corneas displayed a 30–130% increase in material stiffness [Etangent(RGE) = 0.94 ± 0.18 MPa to 3.09 ± 0.66 MPa; Etangent(normals) = 0.72 ± 0.13 MPa to 1.34 ± 0.35 MPa] (P ≤ 0.05). The normal in-plane disposition of anterior collagen in the peripheral cornea was altered in RGE but through-plane lamellar interlacing was unaffected. Conclusions. This article demonstrates changes in corneal material behavior in RGE that are qualitatively consistent with microstructural collagen alterations identified both herein and previously. This study indicates that, in general, changes in stromal fibril orientation may significantly affect corneal material behavior and thereby its response to IOP. PMID:21051696

  12. Safety and efficacy of nano lamellar TiN coatings on nitinol atrial septal defect occluders in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhi xiong, E-mail: Top5460@163.com [Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Fu, Bu fang, E-mail: fubnicpbp@163.com [National Institutes for Food and Drug Control, Beijing (China); Zhang, De yuan, E-mail: Deyuanzhangcn@yahoo.com.cn [Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen (China); Zhang, Zhi wei, E-mail: Zhzhx65@163.com [Guangdong Cardiovascular Institute, Guangzhou (China); Cheng, Yan, E-mail: chengyan@pku.edu.cn [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing (China); Sheng, Li yuan, E-mail: lysheng@yeah.net [Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Lai, Chen, E-mail: laichen1110@163.com [Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Xi, Ting fei, E-mail: Xitingfie@pku.edu.cn [Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Academy for Advanced Interdisciplinary Studies, Peking University, Beijing (China)

    2013-04-01

    Atrial septal defect (ASD) occlusion devices made of nickel–titanium (NiTi) have a major shortcoming in that they release nickel into the body. We modified NiTi occluders using Arc Ion Plating technology. Nano lamellar titanium–nitrogen (TiN) coatings were formed on the surfaces of the occluders. The safety and efficacy of the modified NiTi occluders were evaluated in animal model. The results showed that 38 out of 39 rams (97%) survived at the end of the experiment. Fibrous capsules formed on the surfaces of the devices. Gradual endothelialization took place through the attachment of endothelial progenitor cells from the blood and the migration of endothelial cells from adjacent endocardium. The neo-endocardium formed more quickly in the coated group than in the uncoated group, as indicated by the evaluation of the six month study group. After TiN coating, there was no significant difference in endothelial cell cycle. TiN coating significantly reduced the release of nickel in both in vivo and in vitro indicating an improved biocompatibility of the nitinol ASD occluders. Superior and modified ASD occluders may provide a good choice for people with nickel allergies after sFDA registration, which is expected in one to two years. - Highlights: ► The nano lamella TiN coating did not change the shape-memory behavior and flexibility of the nitinol occluder. ► Nano lamella TiN coating modifications significantly reduced nickel release from nitinol ASD occluder. ► The new ASD occluder was found to be superior to nitinol ASD occluder with respect to both safety and efficacy.

  13. Development of lamellar gel phase emulsion containing marigold oil (Calendula officinalis) as a potential modern wound dressing.

    Science.gov (United States)

    Okuma, C H; Andrade, T A M; Caetano, G F; Finci, L I; Maciel, N R; Topan, J F; Cefali, L C; Polizello, A C M; Carlo, T; Rogerio, A P; Spadaro, A C C; Isaac, V L B; Frade, M A C; Rocha-Filho, P A

    2015-04-25

    Appropriate therapeutics for wound treatments can be achieved by studying the pathophysiology of tissue repair. Here we develop formulations of lamellar gel phase (LGP) emulsions containing marigold (Calendula officinalis) oil, evaluating their stability and activity on experimental wound healing in rats. LGP emulsions were developed and evaluated based on a phase ternary diagram to select the best LGP emulsion, having a good amount of anisotropic structure and stability. The selected LGP formulation was analyzed according to the intrinsic and accelerated physical stability at different temperatures. In addition, in vitro and in vivo studies were carried out on wound healing rats as a model. The LGP emulsion (15.0% marigold oil; 10.0% of blend surfactants and 75.0% of purified water [w/w/w]) demonstrated good stability and high viscosity, suggesting longer contact of the formulation with the wound. No cytotoxic activity (50-1000 μg/mL) was observed in marigold oil. In the wound healing rat model, the LGP (15 mg/mL) showed an increase in the leukocyte recruitment to the wound at least on days 2 and 7, but reduced leukocyte recruitment after 14 and 21 days, as compared to the control. Additionally, collagen production was reduced in the LGP emulsion on days 2 and 7 and further accelerated the process of re-epithelialization of the wound itself. The methodology utilized in the present study has produced a potentially useful formulation for a stable LGP emulsion-containing marigold, which was able to improve the wound healing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. The use of regularization in inferential measurements

    International Nuclear Information System (INIS)

    Hines, J. Wesley; Gribok, Andrei V.; Attieh, Ibrahim; Uhrig, Robert E.

    1999-01-01

    Inferential sensing is the prediction of a plant variable through the use of correlated plant variables. A correct prediction of the variable can be used to monitor sensors for drift or other failures making periodic instrument calibrations unnecessary. This move from periodic to condition based maintenance can reduce costs and increase the reliability of the instrument. Having accurate, reliable measurements is important for signals that may impact safety or profitability. This paper investigates how collinearity adversely affects inferential sensing by making the results inconsistent and unrepeatable; and presents regularization as a potential solution (author) (ml)

  15. Regularization ambiguities in loop quantum gravity

    International Nuclear Information System (INIS)

    Perez, Alejandro

    2006-01-01

    One of the main achievements of loop quantum gravity is the consistent quantization of the analog of the Wheeler-DeWitt equation which is free of ultraviolet divergences. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible theories. The absence of an UV problem--the existence of well-behaved regularization of the constraints--is intimately linked with the ambiguities arising in the quantum theory. Among these ambiguities is the one associated to the SU(2) unitary representation used in the diffeomorphism covariant 'point-splitting' regularization of the nonlinear functionals of the connection. This ambiguity is labeled by a half-integer m and, here, it is referred to as the m ambiguity. The aim of this paper is to investigate the important implications of this ambiguity. We first study 2+1 gravity (and more generally BF theory) quantized in the canonical formulation of loop quantum gravity. Only when the regularization of the quantum constraints is performed in terms of the fundamental representation of the gauge group does one obtain the usual topological quantum field theory as a result. In all other cases unphysical local degrees of freedom arise at the level of the regulated theory that conspire against the existence of the continuum limit. This shows that there is a clear-cut choice in the quantization of the constraints in 2+1 loop quantum gravity. We then analyze the effects of the ambiguity in 3+1 gravity exhibiting the existence of spurious solutions for higher representation quantizations of the Hamiltonian constraint. Although the analysis is not complete in 3+1 dimensions - due to the difficulties associated to the definition of the physical inner product - it provides evidence supporting the definitions quantum dynamics of loop quantum gravity in terms of the fundamental representation of the gauge group as the only consistent possibilities. If the gauge group is SO(3) we find

  16. Effort variation regularization in sound field reproduction

    DEFF Research Database (Denmark)

    Stefanakis, Nick; Jacobsen, Finn; Sarris, Ioannis

    2010-01-01

    In this paper, active control is used in order to reproduce a given sound field in an extended spatial region. A method is proposed which minimizes the reproduction error at a number of control positions with the reproduction sources holding a certain relation within their complex strengths......), and adaptive wave field synthesis (AWFS), both under free-field conditions and in reverberant rooms. It is shown that effort variation regularization overcomes the problems associated with small spaces and with a low ratio of direct to reverberant energy, improving thus the reproduction accuracy...

  17. New regularities in mass spectra of hadrons

    International Nuclear Information System (INIS)

    Kajdalov, A.B.

    1989-01-01

    The properties of bosonic and baryonic Regge trajectories for hadrons composed of light quarks are considered. Experimental data agree with an existence of daughter trajectories consistent with string models. It is pointed out that the parity doubling for baryonic trajectories, observed experimentally, is not understood in the existing quark models. Mass spectrum of bosons and baryons indicates to an approximate supersymmetry in the mass region M>1 GeV. These regularities indicates to a high degree of symmetry for the dynamics in the confinement region. 8 refs.; 5 figs

  18. Total-variation regularization with bound constraints

    International Nuclear Information System (INIS)

    Chartrand, Rick; Wohlberg, Brendt

    2009-01-01

    We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.

  19. Bayesian regularization of diffusion tensor images

    DEFF Research Database (Denmark)

    Frandsen, Jesper; Hobolth, Asger; Østergaard, Leif

    2007-01-01

    Diffusion tensor imaging (DTI) is a powerful tool in the study of the course of nerve fibre bundles in the human brain. Using DTI, the local fibre orientation in each image voxel can be described by a diffusion tensor which is constructed from local measurements of diffusion coefficients along...... several directions. The measured diffusion coefficients and thereby the diffusion tensors are subject to noise, leading to possibly flawed representations of the three dimensional fibre bundles. In this paper we develop a Bayesian procedure for regularizing the diffusion tensor field, fully utilizing...

  20. Strategies for regular segmented reductions on GPU

    DEFF Research Database (Denmark)

    Larsen, Rasmus Wriedt; Henriksen, Troels

    2017-01-01

    We present and evaluate an implementation technique for regular segmented reductions on GPUs. Existing techniques tend to be either consistent in performance but relatively inefficient in absolute terms, or optimised for specific workloads and thereby exhibiting bad performance for certain input...... is in the context of the Futhark compiler, the implementation technique is applicable to any library or language that has a need for segmented reductions. We evaluate the technique on four microbenchmarks, two of which we also compare to implementations in the CUB library for GPU programming, as well as on two...

  1. Partial regularity of weak solutions to a PDE system with cubic nonlinearity

    Science.gov (United States)

    Liu, Jian-Guo; Xu, Xiangsheng

    2018-04-01

    In this paper we investigate regularity properties of weak solutions to a PDE system that arises in the study of biological transport networks. The system consists of a possibly singular elliptic equation for the scalar pressure of the underlying biological network coupled to a diffusion equation for the conductance vector of the network. There are several different types of nonlinearities in the system. Of particular mathematical interest is a term that is a polynomial function of solutions and their partial derivatives and this polynomial function has degree three. That is, the system contains a cubic nonlinearity. Only weak solutions to the system have been shown to exist. The regularity theory for the system remains fundamentally incomplete. In particular, it is not known whether or not weak solutions develop singularities. In this paper we obtain a partial regularity theorem, which gives an estimate for the parabolic Hausdorff dimension of the set of possible singular points.

  2. Emotion regulation deficits in regular marijuana users.

    Science.gov (United States)

    Zimmermann, Kaeli; Walz, Christina; Derckx, Raissa T; Kendrick, Keith M; Weber, Bernd; Dore, Bruce; Ochsner, Kevin N; Hurlemann, René; Becker, Benjamin

    2017-08-01

    Effective regulation of negative affective states has been associated with mental health. Impaired regulation of negative affect represents a risk factor for dysfunctional coping mechanisms such as drug use and thus could contribute to the initiation and development of problematic substance use. This study investigated behavioral and neural indices of emotion regulation in regular marijuana users (n = 23) and demographically matched nonusing controls (n = 20) by means of an fMRI cognitive emotion regulation (reappraisal) paradigm. Relative to nonusing controls, marijuana users demonstrated increased neural activity in a bilateral frontal network comprising precentral, middle cingulate, and supplementary motor regions during reappraisal of negative affect (P marijuana users relative to controls. Together, the present findings could reflect an unsuccessful attempt of compensatory recruitment of additional neural resources in the context of disrupted amygdala-prefrontal interaction during volitional emotion regulation in marijuana users. As such, impaired volitional regulation of negative affect might represent a consequence of, or risk factor for, regular marijuana use. Hum Brain Mapp 38:4270-4279, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. Efficient multidimensional regularization for Volterra series estimation

    Science.gov (United States)

    Birpoutsoukis, Georgios; Csurcsia, Péter Zoltán; Schoukens, Johan

    2018-05-01

    This paper presents an efficient nonparametric time domain nonlinear system identification method. It is shown how truncated Volterra series models can be efficiently estimated without the need of long, transient-free measurements. The method is a novel extension of the regularization methods that have been developed for impulse response estimates of linear time invariant systems. To avoid the excessive memory needs in case of long measurements or large number of estimated parameters, a practical gradient-based estimation method is also provided, leading to the same numerical results as the proposed Volterra estimation method. Moreover, the transient effects in the simulated output are removed by a special regularization method based on the novel ideas of transient removal for Linear Time-Varying (LTV) systems. Combining the proposed methodologies, the nonparametric Volterra models of the cascaded water tanks benchmark are presented in this paper. The results for different scenarios varying from a simple Finite Impulse Response (FIR) model to a 3rd degree Volterra series with and without transient removal are compared and studied. It is clear that the obtained models capture the system dynamics when tested on a validation dataset, and their performance is comparable with the white-box (physical) models.

  4. Supporting Regularized Logistic Regression Privately and Efficiently

    Science.gov (United States)

    Li, Wenfa; Liu, Hongzhe; Yang, Peng; Xie, Wei

    2016-01-01

    As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc. PMID:27271738

  5. Supporting Regularized Logistic Regression Privately and Efficiently.

    Science.gov (United States)

    Li, Wenfa; Liu, Hongzhe; Yang, Peng; Xie, Wei

    2016-01-01

    As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc.

  6. Multiple graph regularized nonnegative matrix factorization

    KAUST Repository

    Wang, Jim Jing-Yan

    2013-10-01

    Non-negative matrix factorization (NMF) has been widely used as a data representation method based on components. To overcome the disadvantage of NMF in failing to consider the manifold structure of a data set, graph regularized NMF (GrNMF) has been proposed by Cai et al. by constructing an affinity graph and searching for a matrix factorization that respects graph structure. Selecting a graph model and its corresponding parameters is critical for this strategy. This process is usually carried out by cross-validation or discrete grid search, which are time consuming and prone to overfitting. In this paper, we propose a GrNMF, called MultiGrNMF, in which the intrinsic manifold is approximated by a linear combination of several graphs with different models and parameters inspired by ensemble manifold regularization. Factorization metrics and linear combination coefficients of graphs are determined simultaneously within a unified object function. They are alternately optimized in an iterative algorithm, thus resulting in a novel data representation algorithm. Extensive experiments on a protein subcellular localization task and an Alzheimer\\'s disease diagnosis task demonstrate the effectiveness of the proposed algorithm. © 2013 Elsevier Ltd. All rights reserved.

  7. Accelerating Large Data Analysis By Exploiting Regularities

    Science.gov (United States)

    Moran, Patrick J.; Ellsworth, David

    2003-01-01

    We present techniques for discovering and exploiting regularity in large curvilinear data sets. The data can be based on a single mesh or a mesh composed of multiple submeshes (also known as zones). Multi-zone data are typical to Computational Fluid Dynamics (CFD) simulations. Regularities include axis-aligned rectilinear and cylindrical meshes as well as cases where one zone is equivalent to a rigid-body transformation of another. Our algorithms can also discover rigid-body motion of meshes in time-series data. Next, we describe a data model where we can utilize the results from the discovery process in order to accelerate large data visualizations. Where possible, we replace general curvilinear zones with rectilinear or cylindrical zones. In rigid-body motion cases we replace a time-series of meshes with a transformed mesh object where a reference mesh is dynamically transformed based on a given time value in order to satisfy geometry requests, on demand. The data model enables us to make these substitutions and dynamic transformations transparently with respect to the visualization algorithms. We present results with large data sets where we combine our mesh replacement and transformation techniques with out-of-core paging in order to achieve significant speed-ups in analysis.

  8. Supporting Regularized Logistic Regression Privately and Efficiently.

    Directory of Open Access Journals (Sweden)

    Wenfa Li

    Full Text Available As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc.

  9. Multiview Hessian regularization for image annotation.

    Science.gov (United States)

    Liu, Weifeng; Tao, Dacheng

    2013-07-01

    The rapid development of computer hardware and Internet technology makes large scale data dependent models computationally tractable, and opens a bright avenue for annotating images through innovative machine learning algorithms. Semisupervised learning (SSL) therefore received intensive attention in recent years and was successfully deployed in image annotation. One representative work in SSL is Laplacian regularization (LR), which smoothes the conditional distribution for classification along the manifold encoded in the graph Laplacian, however, it is observed that LR biases the classification function toward a constant function that possibly results in poor generalization. In addition, LR is developed to handle uniformly distributed data (or single-view data), although instances or objects, such as images and videos, are usually represented by multiview features, such as color, shape, and texture. In this paper, we present multiview Hessian regularization (mHR) to address the above two problems in LR-based image annotation. In particular, mHR optimally combines multiple HR, each of which is obtained from a particular view of instances, and steers the classification function that varies linearly along the data manifold. We apply mHR to kernel least squares and support vector machines as two examples for image annotation. Extensive experiments on the PASCAL VOC'07 dataset validate the effectiveness of mHR by comparing it with baseline algorithms, including LR and HR.

  10. EIT image reconstruction with four dimensional regularization.

    Science.gov (United States)

    Dai, Tao; Soleimani, Manuchehr; Adler, Andy

    2008-09-01

    Electrical impedance tomography (EIT) reconstructs internal impedance images of the body from electrical measurements on body surface. The temporal resolution of EIT data can be very high, although the spatial resolution of the images is relatively low. Most EIT reconstruction algorithms calculate images from data frames independently, although data are actually highly correlated especially in high speed EIT systems. This paper proposes a 4-D EIT image reconstruction for functional EIT. The new approach is developed to directly use prior models of the temporal correlations among images and 3-D spatial correlations among image elements. A fast algorithm is also developed to reconstruct the regularized images. Image reconstruction is posed in terms of an augmented image and measurement vector which are concatenated from a specific number of previous and future frames. The reconstruction is then based on an augmented regularization matrix which reflects the a priori constraints on temporal and 3-D spatial correlations of image elements. A temporal factor reflecting the relative strength of the image correlation is objectively calculated from measurement data. Results show that image reconstruction models which account for inter-element correlations, in both space and time, show improved resolution and noise performance, in comparison to simpler image models.

  11. Total variation regularization for a backward time-fractional diffusion problem

    International Nuclear Information System (INIS)

    Wang, Liyan; Liu, Jijun

    2013-01-01

    Consider a two-dimensional backward problem for a time-fractional diffusion process, which can be considered as image de-blurring where the blurring process is assumed to be slow diffusion. In order to avoid the over-smoothing effect for object image with edges and to construct a fast reconstruction scheme, the total variation regularizing term and the data residual error in the frequency domain are coupled to construct the cost functional. The well posedness of this optimization problem is studied. The minimizer is sought approximately using the iteration process for a series of optimization problems with Bregman distance as a penalty term. This iteration reconstruction scheme is essentially a new regularizing scheme with coupling parameter in the cost functional and the iteration stopping times as two regularizing parameters. We give the choice strategy for the regularizing parameters in terms of the noise level of measurement data, which yields the optimal error estimate on the iterative solution. The series optimization problems are solved by alternative iteration with explicit exact solution and therefore the amount of computation is much weakened. Numerical implementations are given to support our theoretical analysis on the convergence rate and to show the significant reconstruction improvements. (paper)

  12. Accretion onto some well-known regular black holes

    International Nuclear Information System (INIS)

    Jawad, Abdul; Shahzad, M.U.

    2016-01-01

    In this work, we discuss the accretion onto static spherically symmetric regular black holes for specific choices of the equation of state parameter. The underlying regular black holes are charged regular black holes using the Fermi-Dirac distribution, logistic distribution, nonlinear electrodynamics, respectively, and Kehagias-Sftesos asymptotically flat regular black holes. We obtain the critical radius, critical speed, and squared sound speed during the accretion process near the regular black holes. We also study the behavior of radial velocity, energy density, and the rate of change of the mass for each of the regular black holes. (orig.)

  13. Accretion onto some well-known regular black holes

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul; Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan)

    2016-03-15

    In this work, we discuss the accretion onto static spherically symmetric regular black holes for specific choices of the equation of state parameter. The underlying regular black holes are charged regular black holes using the Fermi-Dirac distribution, logistic distribution, nonlinear electrodynamics, respectively, and Kehagias-Sftesos asymptotically flat regular black holes. We obtain the critical radius, critical speed, and squared sound speed during the accretion process near the regular black holes. We also study the behavior of radial velocity, energy density, and the rate of change of the mass for each of the regular black holes. (orig.)

  14. Accretion onto some well-known regular black holes

    Science.gov (United States)

    Jawad, Abdul; Shahzad, M. Umair

    2016-03-01

    In this work, we discuss the accretion onto static spherically symmetric regular black holes for specific choices of the equation of state parameter. The underlying regular black holes are charged regular black holes using the Fermi-Dirac distribution, logistic distribution, nonlinear electrodynamics, respectively, and Kehagias-Sftesos asymptotically flat regular black holes. We obtain the critical radius, critical speed, and squared sound speed during the accretion process near the regular black holes. We also study the behavior of radial velocity, energy density, and the rate of change of the mass for each of the regular black holes.

  15. Laplacian embedded regression for scalable manifold regularization.

    Science.gov (United States)

    Chen, Lin; Tsang, Ivor W; Xu, Dong

    2012-06-01

    Semi-supervised learning (SSL), as a powerful tool to learn from a limited number of labeled data and a large number of unlabeled data, has been attracting increasing attention in the machine learning community. In particular, the manifold regularization framework has laid solid theoretical foundations for a large family of SSL algorithms, such as Laplacian support vector machine (LapSVM) and Laplacian regularized least squares (LapRLS). However, most of these algorithms are limited to small scale problems due to the high computational cost of the matrix inversion operation involved in the optimization problem. In this paper, we propose a novel framework called Laplacian embedded regression by introducing an intermediate decision variable into the manifold regularization framework. By using ∈-insensitive loss, we obtain the Laplacian embedded support vector regression (LapESVR) algorithm, which inherits the sparse solution from SVR. Also, we derive Laplacian embedded RLS (LapERLS) corresponding to RLS under the proposed framework. Both LapESVR and LapERLS possess a simpler form of a transformed kernel, which is the summation of the original kernel and a graph kernel that captures the manifold structure. The benefits of the transformed kernel are two-fold: (1) we can deal with the original kernel matrix and the graph Laplacian matrix in the graph kernel separately and (2) if the graph Laplacian matrix is sparse, we only need to perform the inverse operation for a sparse matrix, which is much more efficient when compared with that for a dense one. Inspired by kernel principal component analysis, we further propose to project the introduced decision variable into a subspace spanned by a few eigenvectors of the graph Laplacian matrix in order to better reflect the data manifold, as well as accelerate the calculation of the graph kernel, allowing our methods to efficiently and effectively cope with large scale SSL problems. Extensive experiments on both toy and real

  16. Biaxial mechanics and inter-lamellar shearing of stem-cell seeded electrospun angle-ply laminates for annulus fibrosus tissue engineering.

    Science.gov (United States)

    Driscoll, Tristan P; Nakasone, Ryan H; Szczesny, Spencer E; Elliott, Dawn M; Mauck, Robert L

    2013-06-01

    The annulus fibrosus (AF) of the intervertebral disk plays a critical role in vertebral load transmission that is heavily dependent on the microscale structure and composition of the tissue. With degeneration, both structure and composition are compromised, resulting in a loss of AF mechanical function. Numerous tissue engineering strategies have addressed the issue of AF degeneration, but few have focused on recapitulation of AF microstructure and function. One approach that allows for generation of engineered AF with appropriate (+/-)30° lamellar microstructure is the use of aligned electrospun scaffolds seeded with mesenchymal stem cells (MSCs) and assembled into angle-ply laminates (APL). Previous work indicates that opposing lamellar orientation is necessary for development of near native uniaxial tensile properties. However, most native AF tensile loads are applied biaxially, as the disk is subjected to multi-axial loads and is constrained by its attachments to the vertebral bodies. Thus, the objective of this study was to evaluate the biaxial mechanical response of engineered AF bilayers, and to determine the importance of opposing lamellar structure under this loading regime. Opposing bilayers, which replicate native AF structure, showed a significantly higher modulus in both testing directions compared to parallel bilayers, and reached ∼60% of native AF biaxial properties. Associated with this increase in biaxial properties, significantly less shear, and significantly higher stretch in the fiber direction, was observed. These results provide additional insight into native tissue structure-function relationships, as well as new benchmarks for engineering functional AF tissue constructs. Copyright © 2013 Orthopaedic Research Society.

  17. A comparison study of rhodamine B photodegradation over nitrogen-doped lamellar niobic acid and titanic acid under visible-light irradiation.

    Science.gov (United States)

    Li, Xiukai; Kikugawa, Naoki; Ye, Jinhua

    2009-01-01

    A solid-state reaction method with urea as a nitrogen precursor was used to prepare nitrogen-doped lamellar niobic and titanic solid acids (i.e., HNb(3)O(8) and H(2)Ti(4)O(9)) with different acidities for visible-light photocatalysis. The photocatalytic activities of the nitrogen-doped solid acids were evaluated for rhodamine B (RhB) degradation and the results were compared with those obtained over the corresponding nitrogen-doped potassium salts. Techniques such as XRD, BET, SEM, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy were adopted to explore the nature of the materials as well as the characteristics of the doped nitrogen species. It was found that the intercalation of the urea precursor helped to stabilize the layered structures of both lamellar solid acids and enabled easier nitrogen doping. The effects of urea intercalation were more significant for the more acidic HNb(3)O(8) sample than for the less acidic H(2)Ti(4)O(9). Compared with the nitrogen-doped KNb(3)O(8) and K(2)Ti(4)O(9) samples, the nitrogen-doped HNb(3)O(8) and H(2)Ti(4)O(9) solid acids absorb more visible light and exhibit a superior activity for RhB photodegradation under visible-light irradiation. The nitrogen-doped HNb(3)O(8) sample performed the best among all the samples. The results of the current study suggest that the protonic acidity of the lamellar solid-acid sample is a key factor that influences nitrogen doping and the resultant visible-light photocatalysis.

  18. Construction of highly ordered lamellar nanostructures through Langmuir-Blodgett deposition of molecularly thin titania nanosheets tens of micrometers wide and their excellent dielectric properties.

    Science.gov (United States)

    Akatsuka, Kosho; Haga, Masa-aki; Ebina, Yasuo; Osada, Minoru; Fukuda, Katsutoshi; Sasaki, Takayoshi

    2009-05-26

    Exfoliated unilamellar titania nanosheets of Ti(0.87)O(2) with a lateral size of 10-30 microm were deposited layer-by-layer onto various substrates by Langmuir-Blodgett procedure to produce a highly ordered lamellar nanofilms. The nanosheets dispersed in an aqueous suspension containing quaternary ammonium ions as a supporting electrolyte floated spontaneously at the air/liquid interface, and they were successfully transferred onto the substrate after surface compression. Neat tiling of the nanosheets could be realized at an optimized surface pressure. The film thus obtained was exposed to UV light to turn the substrate surface hydrophilic, which was helpful for stable repetition of monolayer deposition. Layer-by-layer growth was confirmed by UV-visible absorption spectra, which showed progressive enhancement of an absorption band due to the nanosheet. Cross-sectional transmission electron microscopy images visualized the ultrathin film homogeneously deposited on the substrate surface and a lamellar fringe of the layer-by-layer assembled nanosheets was clearly resolved at a higher magnification. X-ray diffraction data on the films showed sharp basal reflections up to the seventh order, and Williamson-Hall analysis of the pattern indicated that the film was coherent across the total thickness with respect to X-ray and that the lattice strain was extremely small. In addition, the first basal reflection was accompanied by small satellite peaks, which are accounted for by the Laue interference function. All these features clearly indicate the formation of a highly ordered lamellar nanostructure of the titania nanosheets comparable to artificial lattice films produced via modern vapor-phase deposition processes. The obtained films showed superior dielectric and insulating properties as a reflection of the highly organized film nanoarchitecture.

  19. 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

  20. Regularities of radiorace formation in yeasts

    International Nuclear Information System (INIS)

    Korogodin, V.I.; Bliznik, K.M.; Kapul'tsevich, Yu.G.; Petin, V.G.; Akademiya Meditsinskikh Nauk SSSR, Obninsk. Nauchno-Issledovatel'skij Inst. Meditsinskoj Radiologii)

    1977-01-01

    Two strains of diploid yeast, namely, Saccharomyces ellipsoides, Megri 139-B, isolated under natural conditions, and Saccharomyces cerevisiae 5a x 3Bα, heterozygous by genes ade 1 and ade 2, were exposed to γ-quanta of Co 60 . The content of cells-saltants forming colonies with changed morphology, that of the nonviable cells, cells that are respiration mutants, and cells-recombinants by gene ade 1 and ade 2, has been determined. A certain regularity has been revealed in the distribution among the colonies of cells of the four types mentioned above: the higher the content of cells of some one of the types, the higher that of the cells having other hereditary changes

  1. Regularization destriping of remote sensing imagery

    Science.gov (United States)

    Basnayake, Ranil; Bollt, Erik; Tufillaro, Nicholas; Sun, Jie; Gierach, Michelle

    2017-07-01

    We illustrate the utility of variational destriping for ocean color images from both multispectral and hyperspectral sensors. In particular, we examine data from a filter spectrometer, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar Partnership (NPP) orbiter, and an airborne grating spectrometer, the Jet Population Laboratory's (JPL) hyperspectral Portable Remote Imaging Spectrometer (PRISM) sensor. We solve the destriping problem using a variational regularization method by giving weights spatially to preserve the other features of the image during the destriping process. The target functional penalizes the neighborhood of stripes (strictly, directionally uniform features) while promoting data fidelity, and the functional is minimized by solving the Euler-Lagrange equations with an explicit finite-difference scheme. We show the accuracy of our method from a benchmark data set which represents the sea surface temperature off the coast of Oregon, USA. Technical details, such as how to impose continuity across data gaps using inpainting, are also described.

  2. The Regularity of Optimal Irrigation Patterns

    Science.gov (United States)

    Morel, Jean-Michel; Santambrogio, Filippo

    2010-02-01

    A branched structure is observable in draining and irrigation systems, in electric power supply systems, and in natural objects like blood vessels, the river basins or the trees. Recent approaches of these networks derive their branched structure from an energy functional whose essential feature is to favor wide routes. Given a flow s in a river, a road, a tube or a wire, the transportation cost per unit length is supposed in these models to be proportional to s α with 0 measure is the Lebesgue density on a smooth open set and the irrigating measure is a single source. In that case we prove that all branches of optimal irrigation trees satisfy an elliptic equation and that their curvature is a bounded measure. In consequence all branching points in the network have a tangent cone made of a finite number of segments, and all other points have a tangent. An explicit counterexample disproves these regularity properties for non-Lebesgue irrigated measures.

  3. Singular tachyon kinks from regular profiles

    International Nuclear Information System (INIS)

    Copeland, E.J.; Saffin, P.M.; Steer, D.A.

    2003-01-01

    We demonstrate how Sen's singular kink solution of the Born-Infeld tachyon action can be constructed by taking the appropriate limit of initially regular profiles. It is shown that the order in which different limits are taken plays an important role in determining whether or not such a solution is obtained for a wide class of potentials. Indeed, by introducing a small parameter into the action, we are able circumvent the results of a recent paper which derived two conditions on the asymptotic tachyon potential such that the singular kink could be recovered in the large amplitude limit of periodic solutions. We show that this is explained by the non-commuting nature of two limits, and that Sen's solution is recovered if the order of the limits is chosen appropriately

  4. Two-pass greedy regular expression parsing

    DEFF Research Database (Denmark)

    Grathwohl, Niels Bjørn Bugge; Henglein, Fritz; Nielsen, Lasse

    2013-01-01

    We present new algorithms for producing greedy parses for regular expressions (REs) in a semi-streaming fashion. Our lean-log algorithm executes in time O(mn) for REs of size m and input strings of size n and outputs a compact bit-coded parse tree representation. It improves on previous algorithms...... by: operating in only 2 passes; using only O(m) words of random-access memory (independent of n); requiring only kn bits of sequentially written and read log storage, where k ... and not requiring it to be stored at all. Previous RE parsing algorithms do not scale linearly with input size, or require substantially more log storage and employ 3 passes where the first consists of reversing the input, or do not or are not known to produce a greedy parse. The performance of our unoptimized C...

  5. Discriminative Elastic-Net Regularized Linear Regression.

    Science.gov (United States)

    Zhang, Zheng; Lai, Zhihui; Xu, Yong; Shao, Ling; Wu, Jian; Xie, Guo-Sen

    2017-03-01

    In this paper, we aim at learning compact and discriminative linear regression models. Linear regression has been widely used in different problems. However, most of the existing linear regression methods exploit the conventional zero-one matrix as the regression targets, which greatly narrows the flexibility of the regression model. Another major limitation of these methods is that the learned projection matrix fails to precisely project the image features to the target space due to their weak discriminative capability. To this end, we present an elastic-net regularized linear regression (ENLR) framework, and develop two robust linear regression models which possess the following special characteristics. First, our methods exploit two particular strategies to enlarge the margins of different classes by relaxing the strict binary targets into a more feasible variable matrix. Second, a robust elastic-net regularization of singular values is introduced to enhance the compactness and effectiveness of the learned projection matrix. Third, the resulting optimization problem of ENLR has a closed-form solution in each iteration, which can be solved efficiently. Finally, rather than directly exploiting the projection matrix for recognition, our methods employ the transformed features as the new discriminate representations to make final image classification. Compared with the traditional linear regression model and some of its variants, our method is much more accurate in image classification. Extensive experiments conducted on publicly available data sets well demonstrate that the proposed framework can outperform the state-of-the-art methods. The MATLAB codes of our methods can be available at http://www.yongxu.org/lunwen.html.

  6. Regularization of Instantaneous Frequency Attribute Computations

    Science.gov (United States)

    Yedlin, M. J.; Margrave, G. F.; Van Vorst, D. G.; Ben Horin, Y.

    2014-12-01

    We compare two different methods of computation of a temporally local frequency:1) A stabilized instantaneous frequency using the theory of the analytic signal.2) A temporally variant centroid (or dominant) frequency estimated from a time-frequency decomposition.The first method derives from Taner et al (1979) as modified by Fomel (2007) and utilizes the derivative of the instantaneous phase of the analytic signal. The second method computes the power centroid (Cohen, 1995) of the time-frequency spectrum, obtained using either the Gabor or Stockwell Transform. Common to both methods is the necessity of division by a diagonal matrix, which requires appropriate regularization.We modify Fomel's (2007) method by explicitly penalizing the roughness of the estimate. Following Farquharson and Oldenburg (2004), we employ both the L curve and GCV methods to obtain the smoothest model that fits the data in the L2 norm.Using synthetic data, quarry blast, earthquakes and the DPRK tests, our results suggest that the optimal method depends on the data. One of the main applications for this work is the discrimination between blast events and earthquakesFomel, Sergey. " Local seismic attributes." , Geophysics, 72.3 (2007): A29-A33.Cohen, Leon. " Time frequency analysis theory and applications." USA: Prentice Hall, (1995).Farquharson, Colin G., and Douglas W. Oldenburg. "A comparison of automatic techniques for estimating the regularization parameter in non-linear inverse problems." Geophysical Journal International 156.3 (2004): 411-425.Taner, M. Turhan, Fulton Koehler, and R. E. Sheriff. " Complex seismic trace analysis." Geophysics, 44.6 (1979): 1041-1063.

  7. Regularized Regression and Density Estimation based on Optimal Transport

    KAUST Repository

    Burger, M.; Franek, M.; Schonlieb, C.-B.

    2012-01-01

    for estimating densities and for preserving edges in the case of total variation regularization. In order to compute solutions of the variational problems, a regularized optimal transport problem needs to be solved, for which we discuss several formulations

  8. Incremental projection approach of regularization for inverse problems

    Energy Technology Data Exchange (ETDEWEB)

    Souopgui, Innocent, E-mail: innocent.souopgui@usm.edu [The University of Southern Mississippi, Department of Marine Science (United States); Ngodock, Hans E., E-mail: hans.ngodock@nrlssc.navy.mil [Naval Research Laboratory (United States); Vidard, Arthur, E-mail: arthur.vidard@imag.fr; Le Dimet, François-Xavier, E-mail: ledimet@imag.fr [Laboratoire Jean Kuntzmann (France)

    2016-10-15

    This paper presents an alternative approach to the regularized least squares solution of ill-posed inverse problems. Instead of solving a minimization problem with an objective function composed of a data term and a regularization term, the regularization information is used to define a projection onto a convex subspace of regularized candidate solutions. The objective function is modified to include the projection of each iterate in the place of the regularization. Numerical experiments based on the problem of motion estimation for geophysical fluid images, show the improvement of the proposed method compared with regularization methods. For the presented test case, the incremental projection method uses 7 times less computation time than the regularization method, to reach the same error target. Moreover, at convergence, the incremental projection is two order of magnitude more accurate than the regularization method.

  9. Dimensional regularization and analytical continuation at finite temperature

    International Nuclear Information System (INIS)

    Chen Xiangjun; Liu Lianshou

    1998-01-01

    The relationship between dimensional regularization and analytical continuation of infrared divergent integrals at finite temperature is discussed and a method of regularization of infrared divergent integrals and infrared divergent sums is given

  10. Bounded Perturbation Regularization for Linear Least Squares Estimation

    KAUST Repository

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

    2017-01-01

    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

  11. Regular Generalized Star Star closed sets in Bitopological Spaces

    OpenAIRE

    K. Kannan; D. Narasimhan; K. Chandrasekhara Rao; R. Ravikumar

    2011-01-01

    The aim of this paper is to introduce the concepts of τ1τ2-regular generalized star star closed sets , τ1τ2-regular generalized star star open sets and study their basic properties in bitopological spaces.

  12. Inner Stucture of Thin Films of Lamellar Poly(styrene-em>b>-butadiene) Diblock Copolymers as revealed by Grazing-Incidence Small-Angle Scattering

    DEFF Research Database (Denmark)

    Busch, Peter; Posselt, Dorthe; Smilgies, Detlef-Matthias

    2007-01-01

    The lamellar orientation in supported, thin films of poly(styrene-b-butadiene) (P(S-b-B)) depends on block copolymer molar mass. We have studied films from nine block copolymer samples with molar masses between 13.9 and 183 kg/mol using grazing-incidence small-angle X-ray scattering (GISAXS) and ...... quantitatively in the framework of our recently developed distorted-wave Born approximation model (Busch, P.; et al. J. Appl. Crystallogr. 2006, 39, 433). The results cannot be explained from enthalpic considerations alone but point to the importance of entropic factors....

  13. Potential for low fracture toughness and lamellar tearing on PWR steam generator and reactor coolant pump supports. Resolution of generic technical activity A-12

    International Nuclear Information System (INIS)

    Snaider, R.P.; Hodge, J.M.; Levin, H.A.; Zudans, J.J.

    1979-10-01

    This report summarizes work performed by the Nuclear Regulatory Commission staff and its contractor, Sandia Laboratories, in the resolution of Generic Technical Activity A-12, ''Potential for Low Fracture Toughness and Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports.'' The report describes the technical issues, the technical studies performed by Sandia describes the technical issues, the technical studies performed by Sandia Laboratories, the NRC staff's technical positions based on these studies, and the staff's plan for implementing its technical positions. It also provides recommendations for further work. The complete technical input from Sandia Laboratories is appended to the report

  14. Influence of electropulsing globularization on the microstructure and mechanical properties of Ti–6Al–4V alloy strip with lamellar microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Xiaoxin, E-mail: xiaoxinye905@gmail.com [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory for Advanced Materials of Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Tse, Zion T.H. [College of Engineering, The University of Georgia, Athens, GA 30602 (United States); Tang, Guoyi, E-mail: tanggy@mails.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory for Advanced Materials of Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Geng, Yubo [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory for Advanced Materials of Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Song, Guolin [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2015-01-12

    The effect of high-energy electropulsing treatment (EPT) on the microstructure and mechanical properties of Ti–6Al–4V alloy strip with initial lamellar microstructure was investigated. The results indicated that EPT accelerated the phase change process tremendously inducing equiaxed microstructure in titanium alloy. The EPT-induced microstructural change resulted in remarkably increasing elongation-to-failure while the tensile strength remained unchanged. A mechanism for rapid phase change in low temperature during EPT was proposed based on the reduction of nucleation thermodynamic barrier and enhancement of atomic diffusion. A medium migration model was utilized for discussing the globularization process.

  15. Influence of electropulsing globularization on the microstructure and mechanical properties of Ti–6Al–4V alloy strip with lamellar microstructure

    International Nuclear Information System (INIS)

    Ye, Xiaoxin; Tse, Zion T.H.; Tang, Guoyi; Geng, Yubo; Song, Guolin

    2015-01-01

    The effect of high-energy electropulsing treatment (EPT) on the microstructure and mechanical properties of Ti–6Al–4V alloy strip with initial lamellar microstructure was investigated. The results indicated that EPT accelerated the phase change process tremendously inducing equiaxed microstructure in titanium alloy. The EPT-induced microstructural change resulted in remarkably increasing elongation-to-failure while the tensile strength remained unchanged. A mechanism for rapid phase change in low temperature during EPT was proposed based on the reduction of nucleation thermodynamic barrier and enhancement of atomic diffusion. A medium migration model was utilized for discussing the globularization process

  16. Exclusion of children with intellectual disabilities from regular ...

    African Journals Online (AJOL)

    Study investigated why teachers exclude children with intellectual disability from the regular classrooms in Nigeria. Participants were, 169 regular teachers randomly selected from Oyo and Ogun states. Questionnaire was used to collect data result revealed that 57.4% regular teachers could not cope with children with ID ...

  17. 39 CFR 6.1 - Regular meetings, annual meeting.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Regular meetings, annual meeting. 6.1 Section 6.1 Postal Service UNITED STATES POSTAL SERVICE THE BOARD OF GOVERNORS OF THE U.S. POSTAL SERVICE MEETINGS (ARTICLE VI) § 6.1 Regular meetings, annual meeting. The Board shall meet regularly on a schedule...

  18. Recognition Memory for Novel Stimuli: The Structural Regularity Hypothesis

    Science.gov (United States)

    Cleary, Anne M.; Morris, Alison L.; Langley, Moses M.

    2007-01-01

    Early studies of human memory suggest that adherence to a known structural regularity (e.g., orthographic regularity) benefits memory for an otherwise novel stimulus (e.g., G. A. Miller, 1958). However, a more recent study suggests that structural regularity can lead to an increase in false-positive responses on recognition memory tests (B. W. A.…

  19. 5 CFR 551.421 - Regular working hours.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Regular working hours. 551.421 Section... Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... distinction based on whether the activity is performed by an employee during regular working hours or outside...

  20. 20 CFR 226.35 - Deductions from regular annuity rate.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Deductions from regular annuity rate. 226.35... COMPUTING EMPLOYEE, SPOUSE, AND DIVORCED SPOUSE ANNUITIES Computing a Spouse or Divorced Spouse Annuity § 226.35 Deductions from regular annuity rate. The regular annuity rate of the spouse and divorced...