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Articles 20431 - 20460 of 21971

Full-Text Articles in Physical Sciences and Mathematics

Attractor Systems And Analog Computation, Hava Siegelmann, Shmuel Fishman Mar 1998

Attractor Systems And Analog Computation, Hava Siegelmann, Shmuel Fishman

Hava Siegelmann

Attractor systems are useful in neurodynamics, mainly in the modeling of associative memory. This paper presents a complexity theory for continuous phase space dynamical systems with discrete or continuous time update, which evolve to attractors. In our framework we associate complexity classes with different types of attractors. Fixed points belong to the class BPPd, while chaotic attractors are in NPd. The BPP=NP question of classical complexity theory is translated into a question in the realm of chaotic dynamical systems. This theory enables an algorithmic analysis of attractor networks and flows for the solution of various problem such as linear programming. …


A Re-Evaluation Of Profile Shapes From Resonance Line Scattering In Spherical Stellar Winds., R. Ignace Mar 1998

A Re-Evaluation Of Profile Shapes From Resonance Line Scattering In Spherical Stellar Winds., R. Ignace

Richard Ignace

It is common to treat the scattering of light by resonance lines as isotropic, but in fact it has been known for some time that general resonance line scattering is partially isotropic and partially dipolar, the relative strength of the two components depending on the specific transition. As a result, the profile shapes of lines that scatter with strong dipole distributions could in principle differ markedly from those that scatter isotropically. This paper explores the consequences of general resonance line scattering in spherically symmetric stellar envelopes. As a simplified example, a resonance line profile arising in a constant expansion wind …


Sublimation Enthalpies At 298.15 K Using Correlation Gas Chromatography And Differential Scanning Calorimetry Measurements, James Chickos, Donald Hesse, Sarah Hosseini, Gary Nichols, Paul Webb Mar 1998

Sublimation Enthalpies At 298.15 K Using Correlation Gas Chromatography And Differential Scanning Calorimetry Measurements, James Chickos, Donald Hesse, Sarah Hosseini, Gary Nichols, Paul Webb

James Chickos

No abstract provided.


Synthesis Of Licoo2 Powders For Lithium-Ion Batteries From Precursors Derived By Rotary Evaporation., P. Kumpta, D. Gallet, A. Waghray, G. Blomgren, Michael Setter Mar 1998

Synthesis Of Licoo2 Powders For Lithium-Ion Batteries From Precursors Derived By Rotary Evaporation., P. Kumpta, D. Gallet, A. Waghray, G. Blomgren, Michael Setter

Michael P. Setter

Lithium cobalt oxide (LiCoO2) has received considerable attention in the last few years and is a well-known cathode material for high voltage (4 V) rechargeable Li-ion batteries. A simple chemical approach based on aqueous solution chemistry has been developed to synthesize molecularly mixed amorphous precursors. The precursors begin to transform to form LiCoO2 upon heat treatment at temperatures as low as 400°C. Strong peaks characteristic of the desired high temperature (HT) phase of LiCoO2 evolve when the precursors are heat treated to 800°C for 2 h. The morphology and particle size of the powders have been examined using scanning electron …


(Wa: 085755475693) Jual Obat Aborsi Di Indramayu, Aborsi Cytotec, Aborsi Cytotec Mar 1998

(Wa: 085755475693) Jual Obat Aborsi Di Indramayu, Aborsi Cytotec, Aborsi Cytotec

aborsi cytotec

PERCAYAKAN pada saya maka anda tidak akan menyesal. jangan pernah coba coba dalam hal obat yg di minum karena obat yg sudah masuk ke dalam tubuh bekerja langsung ke dalam organ dan syaraf tubuh jadi pilihlah obat yg pasti, ambil obat yg berkualitas tinggi dan tentunya harga juga sedikit tinggi karna memang teruji keaslianya dan kualitas nya


(Wa: 085755475693) Jual Obat Aborsi Di Banda Aceh, Aborsi Cytotec, Aborsi Cytotec Mar 1998

(Wa: 085755475693) Jual Obat Aborsi Di Banda Aceh, Aborsi Cytotec, Aborsi Cytotec

aborsi cytotec

PERCAYAKAN pada saya maka anda tidak akan menyesal. jangan pernah coba coba dalam hal obat yg di minum karena obat yg sudah masuk ke dalam tubuh bekerja langsung ke dalam organ dan syaraf tubuh jadi pilihlah obat yg pasti, ambil obat yg berkualitas tinggi dan tentunya harga juga sedikit tinggi karna memang teruji keaslianya dan kualitas nya


The Voltammetry Of C84 Isomers, Mark Anderson, Harry Dorn, Steven Stevenson, Susanne Dana Mar 1998

The Voltammetry Of C84 Isomers, Mark Anderson, Harry Dorn, Steven Stevenson, Susanne Dana

Mark R. Anderson

The square-wave voltammetry of isolated isomers of C84 is reported. Based on their relative abundance, the isomers are assumed to have D2 and D2d symmetry. The D2 isomer has four reversible reductions at −0.65, −0.98, −1.34, and −1.75 V versus Fc/Fc+ prior to electrolyte decomposition. This behavior is consistent with previous reports, and is similar to the voltammetry of C60 and C70 (e.g. sequential reductions spaced at slightly increasing intervals). The D2d isomer has five reversible reductions at −0.46, −0.77, −1.58, −1.98, and −2.27 V versus Fc/Fc+ prior to the onset of electrolyte decomposition. The large potential difference separating the …


(Wa: 085755475693) Jual Obat Aborsi Di Kuningan, Aborsi Cytotec, Aborsi Cytotec Mar 1998

(Wa: 085755475693) Jual Obat Aborsi Di Kuningan, Aborsi Cytotec, Aborsi Cytotec

aborsi cytotec

PERCAYAKAN pada saya maka anda tidak akan menyesal. jangan pernah coba coba dalam hal obat yg di minum karena obat yg sudah masuk ke dalam tubuh bekerja langsung ke dalam organ dan syaraf tubuh jadi pilihlah obat yg pasti, ambil obat yg berkualitas tinggi dan tentunya harga juga sedikit tinggi karna memang teruji keaslianya dan kualitas nya


31. Yoshio Iwakura, Otto Vogl, Seiichi Nakahama Mar 1998

31. Yoshio Iwakura, Otto Vogl, Seiichi Nakahama

Otto Vogl

No abstract provided.


An Analytical Study Of Ozone Feedbacks On Kelvin And Rossby–Gravity Waves: Effects On The Qbo, Eugene Cordero, Terrence R. Nathan, Robert S. Echols Mar 1998

An Analytical Study Of Ozone Feedbacks On Kelvin And Rossby–Gravity Waves: Effects On The Qbo, Eugene Cordero, Terrence R. Nathan, Robert S. Echols

Eugene C. Cordero

An equatorial beta-plane model of the middle atmosphere is used to analytically examine the effects of radiative cooling and ozone heating on the spatial and temporal evolution of the quasi-biennial oscillation (QBO). Under the assumption that the diabatic heating is weak and the background fields of wind, temperature, and ozone are slowly varying, a perturbation analysis yields expressions describing the vertical spatial modulation of Kelvin and Rossby–gravity waves in the presence of ozone. These expressions show that wave-induced changes in the diabatic heating arising from the advection of basic-state ozone reduce the local radiative damping rate by up to 15% …


A Protocol For Correcting Experimental Fusion Enthalpies To 298.15 K And It's Application In Indirect Measurements Of Sublimation Enthalpy At 298.15 K, James S. Chickos Feb 1998

A Protocol For Correcting Experimental Fusion Enthalpies To 298.15 K And It's Application In Indirect Measurements Of Sublimation Enthalpy At 298.15 K, James S. Chickos

James Chickos

No abstract provided.


Imaging The Molecular Dimensions And Oligomerization Of Proteins At Liquid/Solid Interfaces, Mark Waner, Martha Gilchrist, Melvin Schindler, Marcos Dantus Feb 1998

Imaging The Molecular Dimensions And Oligomerization Of Proteins At Liquid/Solid Interfaces, Mark Waner, Martha Gilchrist, Melvin Schindler, Marcos Dantus

Mark J. Waner

Individual Concanavalin A (ConA) molecules have been imaged at the liquid/solid interface with an atomic force microscope (AFM). Three-dimensional sizing with very high resolution (<5 Å) has been obtained by a novel approach based on height distributions, which avoids the tip convolution effects which normally affect scanning probe microscopy techniques. Each height measurement correlates to a particular molecular orientation on the surface. A large number of such measurements provide a statistical ensemble of orientations. The complete height distribution reflects the three-dimensional size of the protein sample and hence its tertiary and quaternary structure. A surface adsorption and orientation model, based on a minimization of surface adsorption energy, is proposed. This model is in good agreement with the observed height distribution of Con A molecules at the liquid/solid interface. Analysis of Con A and succinylated Con A molecules on mica demonstrates that Con A dimers are the prevalent species at the liquid/solid interface. This is in contrast to the tetrameric organization of Con A normally observed in solution. The new possibilities opened by height distribution analysis on the physical characterization of biomolecules at interfaces are also discussed.


Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun Feb 1998

Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun

Min S. Yun

We have searched for redshifted neutral hydrogen 21 cm absorption toward sources from the Stickel et al. "red quasar" subsample. The red quasar subsample is taken from the 1 Jy sample of flat-spectrum radio sources and is comprised of the 15 sources that are undetected on the POSS. Five of these red quasars have been searched for redshifted H I 21 cm absorption to optical depth levels of a few percent, and four show strong absorption, with neutral hydrogen column densities between 4 and 80 × 1018 × (Ts/f) cm-2. This 80% success rate for the red quasars compares to …


(Wa: 085755475693) Jual Obat Aborsi Di Garut, Aborsi Cytotec, Aborsi Cytotec Feb 1998

(Wa: 085755475693) Jual Obat Aborsi Di Garut, Aborsi Cytotec, Aborsi Cytotec

aborsi cytotec

PERCAYAKAN pada saya maka anda tidak akan menyesal. jangan pernah coba coba dalam hal obat yg di minum karena obat yg sudah masuk ke dalam tubuh bekerja langsung ke dalam organ dan syaraf tubuh jadi pilihlah obat yg pasti, ambil obat yg berkualitas tinggi dan tentunya harga juga sedikit tinggi karna memang teruji keaslianya dan kualitas nya


Piece Cementowe - Konkurencja Dla Spalarni Odpadów, Robert Oleniacz Feb 1998

Piece Cementowe - Konkurencja Dla Spalarni Odpadów, Robert Oleniacz

Robert Oleniacz

The paper presents the advantages of cement kilns and the possibility of their use for thermal waste utilization. The most common types of waste incinerated in these kilns and the possible degree of replacing traditional fuels with waste fuels have also been characterized. The work also discusses the problem of air pollutant emissions from the process of waste co-incineration in cement kilns. Attention has been paid to the possible increase in the use of Polish cement industry in the waste management, system, especially in the field of energy recovery from solid municipal waste, waste tires and waste from the refinery …


Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part Ii. Microstructure And Mechanism, Xiaoli Tan, H. Guo, H. Gu, C. Laird, N. D. H. Monroe Feb 1998

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part Ii. Microstructure And Mechanism, Xiaoli Tan, H. Guo, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Strain-controlled cyclic tests have been conducted on high-purity titanium single crystals with different orientations. The fatigue mechanisms of the titanium crystals were studied by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It was found that single slip lines, wavy slip lines, double slip lines, twins, and associated slip lines occurred in differently oriented single crystals. A new type of fractographic morphology, parallel traces, was observed. Dislocation patterns and cyclic twins, as well as the mechanical response, were analyzed. The dependence of the deformation mechanisms on the orientations of the single crystals is discussed.


Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part I. Orientation Dependence Of Stress-Strain Response, Xiaoli Tan, H. Gu, C. Laird, N. D. H. Monroe Feb 1998

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part I. Orientation Dependence Of Stress-Strain Response, Xiaoli Tan, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Randomly oriented single crystals of high-purity titanium were prepared by strain annealing and were subjected to multiple-step fatigue testing under strain-controlled conditions, in order to determine their cyclic stress-strain curves (CSSCs). These were found to fall into three groups, depending on orientation and the extent of slip and twinning. For those crystals oriented for single prismatic slip, a plateau was observed in the CSSCs, persistent slip bands (PSBs) occurred, and the plateau stress was 38 MPa. In a second group, oriented for prismatic slip but for which cross-slip and twinning was favored, the plateau was suppressed and the flow stresses …


32. Ian Macmillan Ward, Otto Vogl Feb 1998

32. Ian Macmillan Ward, Otto Vogl

Otto Vogl

No abstract provided.


Murnaghan-Nakayama Rules For Characters Of Iwahori-Hecke Algebras Of The Complex Reflection Groups G(R,P,N), Thomas Halverson, A. Ram Feb 1998

Murnaghan-Nakayama Rules For Characters Of Iwahori-Hecke Algebras Of The Complex Reflection Groups G(R,P,N), Thomas Halverson, A. Ram

Thomas M. Halverson

No abstract provided.


Kempe Revisited, Joan Hutchinson, Stan Wagon Jan 1998

Kempe Revisited, Joan Hutchinson, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Trade In Medicinal Plants: The Need For It To Be Carried Out Based On The Principle Of Conservation, Nat Quansah Jan 1998

Trade In Medicinal Plants: The Need For It To Be Carried Out Based On The Principle Of Conservation, Nat Quansah

Nat Quansah

No abstract provided.


Density Fluctuations In Vibrated Granular Materials , E.R. Nowak, J.B. Knight, E. Ben-Naim, H.M Jaeger, S.R. Nagel Jan 1998

Density Fluctuations In Vibrated Granular Materials , E.R. Nowak, J.B. Knight, E. Ben-Naim, H.M Jaeger, S.R. Nagel

Eli Ben-Naim

We report systematic measurements of the density of a vibrated granular material as a function of time. Monodisperse spherical beads were confined to a cylindrical container and shaken vertically. Under vibrations, the density of the pile slowly reaches a final steady-state value about which the density fluctuates. We have investigated the frequency dependence and amplitude of these fluctuations as a function of vibration intensity Γ. The spectrum of density fluctuations around the steady state value provides a probe of the internal relaxation dynamics of the system and a link to recent thermodynamic theories for the settling of granular material. In …


Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Ii. Occultation Effects And The Determination Of Intrinsic Stellar Properties., R. Ignace, J. C. Brown, L. L. Richardson, J. P. Cassinelli Jan 1998

Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Ii. Occultation Effects And The Determination Of Intrinsic Stellar Properties., R. Ignace, J. C. Brown, L. L. Richardson, J. P. Cassinelli

Richard Ignace

This paper extends previous work on the inversion of line profiles to obtain wind velocity laws to a case that includes the occultation of light from the far side of the star. The velocity law v(r) is assumed to be from a wind that is steady and spherically symmetric. The wind is also assumed to be optically thin in the emission line profile. The major result here is the derivation of an analytic inversion formula. The effects of stellar occultation are shown to produce a significant change in the analysis from paper I, and by accounting for the occultation, the …


Cosmopolitan Distribution Of The Large Composite Microbial Mat Spirochete, Spirosymplokos Deltaeiberi, Lynn Margulis, Antoni Navarrete, Mónica Solé Jan 1998

Cosmopolitan Distribution Of The Large Composite Microbial Mat Spirochete, Spirosymplokos Deltaeiberi, Lynn Margulis, Antoni Navarrete, Mónica Solé

Lynn Margulis (1938 - 2011)

Inocula from organic-rich black muds immediately underlying intertidal laminated microbial mats dominated by Microcoleus chthonoplastes yielded large, variable diameter spirochetes. These unusual spirochetes, previously reported only from the Alfacs Peninsula at the delta of the Ebro river in northeast Spain, contain striking arrays of cytoplasmic granules packed into their protoplasmic cylinders. On several occasions, both in summer and winter, the huge spirochetes were recognized in samples from mats growing in the Sippewissett salt marsh at Woods Hole Massachusetts. They were also seen in similar samples from microbial mats at North Pond, Laguna Figueroa, Baja California Norte, Mexico. The identity of …


Crossing Of Disclinations In Nematic Slabs, T. Ishikawa, Oleg Lavrentovich Jan 1998

Crossing Of Disclinations In Nematic Slabs, T. Ishikawa, Oleg Lavrentovich

Oleg Lavrentovich

It is shown experimentally that crossing and intercommutation of disclinations in a bounded nematic cell depend on surface orientation of the director and the relative strength of disclinations. Lines of opposite strength switch the pinned ends between the bounding plates and vanish independently of each other if the surface orientation is tangential. In contrast, tilted surface orientation preserves the stability of lines.


Molecular Gas In The Inner 100 Parces Of M51, N Z. Scoville, Min S. Yun, L Armus, H Ford Jan 1998

Molecular Gas In The Inner 100 Parces Of M51, N Z. Scoville, Min S. Yun, L Armus, H Ford

Min S. Yun

We report imaging of CO (2-1) emission in the nucleus of M51 at 1'' (47 pc) resolution. Molecular gas is found closely associated with the nuclear radio jet and the X-shaped dust absorption feature seen in the Hubble Space Telescope images. The CO emission lies along the side of the nuclear radio continuum "jet." The strongest molecular emission is not symmetric in either position or velocity with respect to the nucleus—the dominant feature is at redshifted velocities and peaks 1'' to the west of the radio/optical nucleus. The CO (2-1) emission has an integrated flux implying a molecular gas mass …


Patterns On Liquid Surfaces: Cnoidal Waves, Compactons And Scaling, Andrei Ludu Jan 1998

Patterns On Liquid Surfaces: Cnoidal Waves, Compactons And Scaling, Andrei Ludu

Andrei Ludu

Localized patterns and nonlinear oscillation formation on the bounded free surface of an ideal incompressible liquid are analytically investigated. Cnoidal modes, solitons and compactons, as traveling non-axially symmetric shapes are discussed. A finite-difference differential generalized Korteweg-de Vries equation is shown to describe the three-dimensional motion of the fluid surface and the limit of long and shallow channels one re-obtains the well-known KdV equation. A tentative expansion formula for the representation of the general solution of a nonlinear equation, for given initial condition is introduced on a graphical-algebraic basis. The model is useful in multilayer fluid dynamics, cluster formation, and nuclear …


Wavelets And Quantum Algebras, Andrei Ludu Jan 1998

Wavelets And Quantum Algebras, Andrei Ludu

Andrei Ludu

No abstract provided.


Emisja Zanieczyszczeń Ze Spalania Odpadów Niebezpiecznych W Piecu Obrotowym, Robert Oleniacz, Marian Mazur, Marek Bogacki Jan 1998

Emisja Zanieczyszczeń Ze Spalania Odpadów Niebezpiecznych W Piecu Obrotowym, Robert Oleniacz, Marian Mazur, Marek Bogacki

Robert Oleniacz

The article presents measurement results of air pollutant emissions from incineration of selected hazardous wastes in a full-scale rotary kiln equipped with afterburner and a wet installation for flue gas cleaning. This type of kiln is suitable for thermal disposal of many sorts of wastes, both solid and liquid. Four groups of waste were being incinerated during the tests: coke tars, medical (hospital) and pharmaceutical wastes added to greased cleaning materials, a sawdust and used gloves, varnish and lubrication wastes, as well as waste rubber and resins. The study was performed in order to answer the question: is the process …


Diffusion Of Low Molecular Mass Substances In Glassy Polymers, Sergey Sobolev Jan 1998

Diffusion Of Low Molecular Mass Substances In Glassy Polymers, Sergey Sobolev

Sergey Sobolev

No abstract provided.