bluuebunny/crossref_metadata_2025 huggingface dataset:
Denying Culture in the Transplant Arena: Technocratic
Medicine's Myth of Democratization
Authors: SHARP LESLEY A.
Published: November 2002

In the United States, organ transfer has generated a highly
selective and overly specialized approach to bioethics. A dominant
assumption is the myth of medical democracy: whereas professionals
involved in this highly technocratic arena publicly embrace notions
of medical equality, particularized practices expose another reality.
The more specific ideological tenets of medical democracy read as
follows: First, all potential transplant patients are equally deserving
of replacement organs. Further, all citizens are entitled to equal
access to these unusual commodities, which are regularly described
as precious and scarce “national resources.” Whether the
premises of medical democracy are in fact played out in daily practice,
however, is another matter entirely. Organ donation is driven by a
universalized sense of humanity, whereby all bodies are assumed
equal beneath the surgeon's knife. Yet the social worth
of individuals varies radically: children, pregnant women, the
unemployed, and prisoners, for example, expose a wide spectrum
of responses to certain categories of bodies. So, too, do the
cultural origins of organ donors. By drawing on anthropological
knowledge of sociomedical practices relevant to organ transfer,
this essay explores this theme of medical democracy specifically
in reference to the needs of Latinos in New York City.
Genetic Testing
Authors: BOYLAN MICHAEL
Published: November 2002

As one looks into the crystal ball concerning the future of
medicine, what might be seen? One vision is of genetic testing
being carried out by medical technicians and then, as a result
of this analysis, patients will be given a diagnosis of what
is wrong with them. Next, they will be given a list of courses
of action based on the tests. (Again, this list could be obtained
by a technician who merely transfers the test results to the
accepted database.) Once the list is presented to the patient,
then she will choose her treatment (with the help, perhaps,
of some online tutorials). Then a clinician will inoculate her
or otherwise administer the genetic therapy. The entire process
might go forward without the intervention of a physician!
Relational Professional Autonomy
Authors: MacDONALD CHRIS
Published: November 2002

The notion of “relational” autonomy—as described
by feminist scholars such as Susan Sherwin and Anne Donchin—has
been the subject of a significant body of literature over the last few
years and has recently generated some interest within the field of
bioethics. Although the focus of this interest has been the autonomy of
ordinary moral agents, the analysis of relational autonomy can usefully
be extended to apply to the autonomy of professionals, not only as
individual moral agents, but in their roles as professionals as well.
In this paper, I argue that professional autonomy, rightly understood,
is relational in nature. This understanding of professional autonomy
stands to improve our understanding of professional ethics, as well as
providing a particular, concrete example of what we mean when we call
autonomy “relational” and “socially embedded.
CQ Sources/Bibliography
Authors: Young Judith Schaeffer
Published: November 2002

These CQ Sources were compiled by Judith Schaeffer Young.
Asylum Evaluations—The Physician's Dilemma
Authors: WEINSTEIN HARVEY M. , STOVER ERIC
Published: November 2002

In the following paper, Annemiek Richters of the University
of Leiden in the Netherlands addresses the dilemmas faced by
health professionals who are asked to evaluate and provide
supporting documentation for those refugees who seek political
asylum in the countries of Europe. It is in the politically
charged arena of asylum applications, government regulations,
and public policy where bioethics, human rights, and health
converge. Despite the 1951 Convention on Refugees, a treaty
signed by nations around the world to safeguard the rights of
those who are displaced, and other treaties that protect the
rights of vulnerable populations, refugee and asylum policies
have become increasingly strict in an effort to deter those
who would seek safety. This tightening of borders in the countries
of the West challenges physicians who find themselves caught
between obligations to treat, to advocate, and to challenge
policies that make treatment a potentially dangerous proposition.
Unfortunately, the World Trade Center attacks have exacerbated
the problem by labeling asylees and refugees as potential
terrorists and subject to deportation.
When Ethics, Healthcare, and Human Rights Conflict: Mental
Healthcare for Asylum Seekers
Authors: Richters Annemiek
Published: November 2002

Mental health professionals who care for asylum seekers in
Western European countries increasingly encounter problems for
which standard diagnostic and therapeutic protocols and institutional
healthcare policies offer no ready answers. In the following case
vignettes some of these problems can be identified.
The Postsocialist Experience and Comparative
Politics
Authors: Bunce Valerie
Published: November 2002

I see four areas where the study of postsocialism has made
significant contributions to our understanding of politics, One is
in providing an ideal laboratory for comparison. Here, I refer to
three aspects of the region. First, it contains a large number of
cases—28 in all and a good deal more, once we take into account
“patch-work” politics and economics of the Russian Federation, for
example. Second, the “great transformation,” to borrow from Polanyi
and to refer in this instance to an even “greater” process involving
the construction of economic and political regimes, nations, and
states, deals with virtually all the fundamental
issues of politics. Finally, the region exhibits enormous variation
in political and economic outcomes, whether we focus on economic and
political regime types and the institutional details of these
regimes; economic performance, levels of economic development, types
of economic reforms, and the role of foreign capital; the age and
size of the state and its capacity to define and defend borders,
command compliance and extract resources; and the national
composition of the population. At the same time, causes are limited,
largely because of the homogenizing effects of state socialism and
the temporal similarities in when these great transformations
commenced. This combination of variable outcomes and constrained
causes is, of course, precisely what comparativists value.
Was the 2000 Presidential Election
Predictable?
Authors: Erikson Robert S. , Bafumi Joseph , Wilson Bret
Published: November 2002

In late August 2000, at APSA's Annual Meeting, a panel of political
scientists offered forecasts for the 2000 presidential election.
Although they differed in particulars, most of the forecasters'
models incorporated a measure of economic growth plus the
president's approval rating. Because the economy was prospering and
President Clinton enjoyed phenomenal approval numbers for the eighth
year of office, the consensus prediction was a Democratic (Gore)
victory by upwards of 6 percentage points. Although political
scientists had offered forecasts before previous presidential
elections, these political scientists' predictions for 2000
attracted more interest than usual. Their predictions drew
exceptional interest both during the campaign, when nobody knew for
sure how the election would turn out, and after, when the
forecasters had to account for their mistakes.
Introduction: Advisors and the Dissertation
Proposal
Authors: Wasby Stephen L.
Published: November 2002

In the interest of providing graduate students with information and
advice concerning their graduate careers, APSA has begun a series of
efforts to identify “good practices” or “best practices” with
respect to a number of aspects of graduate education. The thought is
that faculty, junior and senior, may serve as sources of useful
information that supplements what departments provide to their own
students, At a minimum, from these efforts, students would be able
to learn of a variety of perspectives, some of which might be
different from those to which they had already been exposed by their
own advisors and other faculty with whom they have studied.
The Key to a Successful Prospectus: Consult an Advisor,
Early and Often
Authors: Benesh Sara C.
Published: November 2002

Failure to develop a dissertation topic and proposal is sometimes the
downfall of graduate students. The course work may go well, exams
may be passed with flying colors, and the students may even
successfully write and present papers at conferences. The elusive
dissertation topic, though, may continue to bring them misery. One
problem is that students may wait too long to develop an idea;
having no concept of what a dissertation should be and not knowing
how to narrow their wide ranging interests into manageable projects,
they flounder. They meet real trouble because they wait until they
finish courses and exams before they even consider the topics on
which to write their dissertations.
Participation by Women in the 2001 APSA
Meeting
Authors: Gruberg Martin
Published: November 2002

This is the thirtieth year that I have been monitoring participation
by women at our annual meeting. These PS reports have documented the
ascent of women in our profession. (At this year's meeting I
reported to the Women's Caucus tracing participation by women in our
programs since the 1970s.) While there are signs that women have
continued to move ahead in their participation, the picture is
mixed.
Scaling parameters for underexpanded supersonic jets
Authors: Yüceil K. Bülent , Ötügen M. Volkan
Published: November 2002

An analysis and experiments were carried out to study the spreading and centerline property decay rates of underexpanded supersonic jets. The main purpose was to determine a suitable set of normalization parameters that would account for the initial expansion process and allow for a comparison of the asymptotic mixing rates of jets within a large range of exit-to-ambient pressure ratios. A set of expressions were developed for after-expansion equivalent jet exit diameter, velocity, temperature, and density to allow for a better collapse of jet spreading and centerline decay rates. Measurements were made for five different underexpanded sonic jets with jet exit-to-ambient pressure ratios of pe/pa=1, 2.5, 7.5, 15.5, and 20.3, corresponding to (isentropically) fully expanded jet Mach numbers of Mj=1, 1.68, 2.38, 2.85, and 3.03, respectively. For each jet, both centerline and profile measurements were made using special probes that simultaneously measured local total pressure, static pressure, total temperature in the jet, as well as ambient conditions. These measurements were made in the subsonic flow regime, in some cases, extending as far as 270 nozzle diameters from the exit plane. The experimental results were analyzed and the asymptotic jet properties were determined using the new renormalization parameters.
Large cyclic deformation of a Ni-Mn-Ga shape memory alloy induced by magnetic fields
Authors: Müllner P. , Chernenko V. A. , Wollgarten M. , Kostorz G.
Published: November 2002

A single-crystalline ferromagnetic Ni-Mn-Ga shape memory specimen was deformed in the martensitic state by uniaxial compression to a total strain of 2%. The stress-strain curve displays a yield point at 6 MPa followed by jerky flow. After mechanical deformation, magnetomechanical tests in a rotating magnetic field of constant strength as well as experiments in a magnetic field of variable strength and constant direction were performed. Upon field rotation, a cyclic-field-induced strain of 1.8% is obtained repeatedly. Upon repeated field variation with constant field direction, a large field-induced strain occurs only in the first test after a change of the field direction. The force of a magnetic field on a twinning dislocation and the resulting magnetostress are discussed. For small fields, the magnetic force is proportional to the applied field. Above the saturation field, the magnetic stress is constant and equals the ratio of the magnetic anisotropy constant and the twinning shear. A microscopic model relating large field-induced strain to the motion of twinning dislocations is presented and applied to the experiments. It is concluded that cyclic magnetic-field-induced strain can be obtained only by changing the field direction because the magnetic force cannot be reversed otherwise.
Single-ion anisotropy in compounds of rare earths other than Sm: Importance of J-mixing in the room-temperature range
Authors: Kuz’min M. D.
Published: November 2002

Contrary to the established view, J-mixing is found to strongly affect the magnetic anisotropy of compounds of all light rare earths and also of terbium. The fractional contribution of J-mixing to second-order anisotropy constants in the room-temperature range is proportional to absolute temperature and depends on the rare earth element involved but not on the characteristics of the specific solid. For the light rare earths this contribution is given by 12(2J−1)−1kT/Δso, where Δso is the spin-orbit splitting between the centers of gravity of the ground and first excited multiplets, and amounts to 22% for Pr and Nd and to as much as 83% for Sm at T=400 K. For the heavy rare earths the corresponding expression is 12(2J+3)−1kT/Δso, which is 11% for Tb at T=400 K and significantly less for the rest of the rare earth series. Analytical expressions are obtained which allow for the J-mixing and are accurate in the room-temperature range for all rare earths with the possible exception of Sm.
Preparation and magnetic properties of La0.9Ca0.1MnO3 nanoparticles at 300 °C
Authors: Ji Tianhao , Fang Jiye , Golob Volodymyr , Tang Jinke , O’Connor Charles J.
Published: November 2002

Nanosized La0.9Ca0.1MnO3 perovskite-type crystalline complex oxides have been prepared at the low calcination temperature of 300 °C. The preparation procedure was carried out by the two-step process of amorphous formation and calcination. The amorphous phase was obtained by the reaction of metal ions with tetrabutylammonium hydroxide at 245 °C, and then calcined at 300 °C (sample A) or 400 °C (sample B) to prepare the nanocrystalline materials. The magnetic measurement shows that spin-glass behavior exists at 45 K and the blocking temperature increases with an increase of calcination temperature. The result of the spin-glass temperature of 45 K demonstrates that the particle size of the two samples A and B is below 50 nm. The increase of blocking temperature from A to B indicates that the particle size of A is less than that of B. The measurement of the normalized resistivity versus temperature for samples A and B shows that they have the change of the normalized resistive value at 230 K.
Density dependence of the optical Kerr effect of linear molecules
Authors: Kiyohara Kenji , Kimura Yoshifumi , Takebayashi Yoshihiro , Hirota Noboru , Ohta Koji
Published: November 2002

We investigated the density dependence of the optical Kerr effect of two linear molecules, CO2 and N2O, by the optical Kerr effect experiment for a wide range of densities higher than the critical density. We also performed molecular dynamics simulation for CO2 in order to analyze the mechanism of the optical response. The density was controlled from the critical density ρc=0.467 g/cm3 to 2.8 times ρc at a supercritical temperature of 323 K. We found good agreement between the experimental and simulation results. The relative importance of orientational dynamics of molecules and the collision-induced polarizability to the optical Kerr effect was studied at the molecular level. In particular, the collective orientational dynamics of the molecules as compared to that of the single molecule and the effect of the dipole-induced-dipole on the optical response function were analyzed in detail. Furthermore, the correspondence between the transition of the response function and the transition of the static structure as a function of density is discussed.
Transient effects in the signaling problem
Authors: Gordillo José M. , Pérez-Saborid Miguel
Published: November 2002

We have obtained a uniformly valid asymptotic solution which accounts for the transient effects which take place during the response to the periodic forcing in the linear signaling problem. This solution complements the results of classical references [Huerre and Monkewitz, J. Fluid Mech. 159, 151 (1985); Annu. Rev. Fluid Mech. 22, 473 (1990); Huerre, in Perspectives in Fluid Dynamics (Cambridge University Press, Cambridge, 2000), pp. 159–229] by determining the spatiotemporal limits for the transition region separating the zone where the response has reached the periodic regime from that free of disturbances. The method of solution is based on the well-known steepest descent technique and does not invoke any type of causality arguments of the type resorted to in above-mentioned works. In addition, our technique provides one with a procedure, alternative to that presented in the above-mentioned works, which permits to identify very easily the direction of propagation (downstream or upstream) of the waves associated with the different spatial eigenvalues of the problem. The asymptotic solution obtained using the general procedure described in this paper has been validated with the numerical results for two relatively simple problems: the forced one-dimensional Ginzburg–Landau equation, and the forced Kelvin–Helmholtz problem.
Nonlinear evolution of nonuniformly heated falling liquid films
Authors: Scheid Benoit , Oron Alexander , Colinet Pierre , Thiele Uwe , Legros Jean Claude
Published: November 2002

The present theoretical study focuses on the dynamics of a thin liquid film falling down a vertical plate with a nonuniform, sinusoidal temperature distribution. The results are compared to those obtained in the case of the uniform temperature distribution. The governing evolution equation for the film thickness profile based on long-wave theory accounts for two instability mechanisms related to thermocapillarity. The first mechanism is due to an inhomogeneity of the temperature at the liquid–gas interface induced by perturbations of the film thickness, when heat transfer to the gas phase is present, while the second one is due to the nonuniform heating imposed at the plate and leads to steady-state deformations of the liquid–gas interface. For a moderate nonuniform heating the traveling waves obtained in the case of a uniform heating are modulated by an envelope. When the temperature modulation along the plate increases the shape of the liquid–gas interface becomes “frozen” and the oscillatory traveling wave regime is suppressed. The enhancement of the heat transfer due to permanent deformations and traveling waves is also assessed. The latter is found to have no significant effect on the heat transfer coefficient, while the former can increase it significantly. A good agreement between the theoretical model and the experimental data obtained for a step-wise temperature distribution at the plate is found and the reason for discrepancies is explained.
An evaluation of cellular automata applied to ganglia dissolution
Authors: Johns M. L. , Gladden L. F.
Published: November 2002

The ability of a three-dimensional (3-D) cellular automaton (CA) approach to describe or mimic the dissolution of entrapped octanol ganglia, trapped in a porous media, into a mobile aqueous phase has been directly assessed using detailed 3-D visualizations of the dissolution process, as provided by magnetic resonance imaging (MRI). In the 3-D CA, both time and space are made discrete with the state of each geometric site being updated after each time increment according to the state of all neighboring sites. Good agreement is produced by a direct 3-D comparison of the CA results with the corresponding images of the dissolving ganglia. These experimental images are also supplemented by 3-D velocity maps of the mobile aqueous phase produced using either MRI or by a lattice-Boltzmann simulation. The velocity maps are used to validate the assumption that a consideration of the local velocity field is essential for an accurate description of the ganglia dissolution process. Based on this analysis, an appropriate length scale is proposed for the region, required to be considered in the respective vicinity of each ganglion, when describing their dissolution using a CA approach.
Axial core-variations of axisymmetric shape on a curved slender vortex filament with a similar, Rankine, or bubble core
Authors: Margerit Daniel
Published: November 2002

The dynamics of axial core-variations of axisymmetric shape on a vortex filament is derived from the Navier–Stokes equations in the slenderness limit. The core of the vortex is of similar, Rankine, or bubble type with a centerline of any shape. In this limit, a two-time-scale asymptotic approach is used to study the dynamics of the axial core-variations and of the centerline. The short-time dynamical equations of the axial core-variations are given and are inviscid at leading and first orders. The induced short-time and normal-time dynamics of the centerline is obtained. The full two-time-scale dynamics of the axial variations and of the filament motion is discussed qualitatively. The normal-time dynamics of vortex filaments without axial core-variations is given in a short form. Within the two-time-scale framework, the dynamics of axial core-variations around this one-time base flow is then studied in the small amplitude limit. The normal-time equations of a vortex bubble are given. The bubble has no axial variations, a centerline of any shape and can have a nonpotential core. The equation for the ultra-short-time dynamics of axial variations on this bubble is given.
Gas-dynamic boundary conditions of evaporation and condensation: Numerical analysis of the Knudsen layer
Authors: Gusarov Andrey V. , Smurov Igor
Published: November 2002

The gas-dynamic Euler equations require two boundary conditions to be specified at the surface of evaporated condensed phase and one condition at the surface of condensation. In the commonly considered three-parameter space of the temperature and pressure ratios and the Mach number this corresponds to a three-dimensional curve in the case of evaporation and to a surface in the case of condensation. To obtain the conditions of evaporation and condensation the steady-state Knudsen layer is numerically studied by the discrete velocity method applied to a Boltzmann equation with a relaxation collision term. Simple models of Mott-Smith type based on the conservation laws and analytical approximations of the velocity distribution function in the Knudsen layer may give satisfactory description of the gas-dynamic evaporation and condensation conditions while in general they inadequately represent the detailed structure of the distribution function. One of the reasons why the models deviate from the calculations is that they do not allow different parallel and perpendicular temperatures of the velocity distribution. Under evaporation, the Knudsen layer thickness increases with the Mach number M. Under condensation, it is inversely proportional to M when M is low. Numerical results are obtained and an analytical model is proposed for the vapor temperature considerably less than the condensed phase one (up to 10 times) what is typical for back condensation under pulsed laser ablation.
Optimal large-eddy simulation of forced Burgers equation
Authors: Das Arup , Moser Robert D.
Published: November 2002

To explore the properties of optimal large eddy simulation (LES) formulations, they have been applied to the case of forced one-dimensional Burgers equation with a Fourier cutoff filter, rather than three-dimensional turbulence for which this approach was developed. This simplified model problem allows more complex models to be evaluated than was possible in three-dimensional turbulence. Further, in “Burgers turbulence,” the small scales consist of shocks, and the evolution of Fourier filtered shocks can be constructed with high accuracy. Thus, the lower bound on the modeling error in this case is known to be very small, if not zero, which makes it possible to correctly interpret the observed errors in the optimal LES models. Optimal LES models were used in Burgers equation LES, and it was found that the solution exhibits shocks similar to the exact solution but that the Gibbs phenomenon that exists in the exact filtered solution is gradually eliminated. This also produced poor results for the high wavenumber spectrum. In contrast, previous optimal LES studies in isotropic turbulence yielded very good results for the spectra. The differences and similarities in performance on Burgers equation and three-dimensional turbulence are instructive for characterizing the properties of optimal LES models.
Photoionization of the primary photoproducts of A(2∏)-excited ClO
Authors: Flesch R. , Plenge J. , Kühl S. , Klusmann M. , Rühl E.
Published: November 2002

Photoionization of the primary photofragments of chlorine monoxide (ClO) is reported. ClO is photolyzed in the X(2∏)→A(2∏)-regime, yielding Cl(2P) and O(3P,1D). The primary photolysis products, as well as the not photolyzed ClO, are subsequently probed by monochromatic, time-correlated vacuum-ultraviolet radiation from a laser produced plasma source. Autoionization is used for state-specific detection of the atomic photolysis products. The formation of O(3P) is exclusively observed above ≈264 nm. The threshold of O(1D) from A(2∏3/2)-excited ClO is found at 263.71±0.01 nm. The shape of the O(1D) yield near this threshold is discussed in terms of the rotational energy distribution and a rotational barrier of A(2∏3/2)-excited ClO. Direct (nonresonant) one-photon-ionization is used to establish the absolute photoionization cross sections of ClO(X(2∏)), Cl(2P), and O(1D) near 15 eV. Additional experiments on the UV-photolysis of Cl2, yielding Cl(2P), are consistent with the results on ClO. The present work is compared to earlier experimental and theoretical studies.
Brillouin–Wigner coupled cluster theory. Fock-space approach
Authors: Petraco Nicholas D. K. , Horný Ľuboš , Schaefer Henry F. , Hubač Ivan
Published: November 2002

The generalization of coupled cluster (CC) theory is far from being a standard method to account for correlation effects of ubiquitous open-shell systems. This dilemma is largely due to three problems. The first concerns the incorporation of multiple reference “guess” wave functions into nonvariational theories. Next is the size-extensivity issue. Finally, and perhaps most importantly is the notorious intruder state problem. Brillouin–Wigner (BW) and generalized Brillouin–Wigner (gBW) perturbation theories are used to aid in the development of new Fock-space coupled cluster theories in an attempt to alleviate some of these problems. Bloch equations are derived which can be used to formulate BWCC and gBWCC theories of arbitrary dimension in all sectors of Fock space. Since this is our first study of Brillouin–Wigner coupled cluster theories in Fock space we have chosen to keep our approach very simple. Explicit effective Hamiltonian and amplitude equations for up to two-body S-amplitudes in the (0,1) and (1,0) sectors are given for the single reference case. Aspects concerning the connectivity of the amplitude equations are addressed.
Potential curves and spectroscopic properties for the ground state of ClO and for the ground and various excited states of ClO−
Authors: Kim Seung-Joon , Kim Young-Joo , Shin Chang-Ho , Mhin Byung-Jin , Crawford T. Daniel
Published: November 2002

The potential curves and dissociation energies for the ground states of ClO(2Π) and ClO−(1Σ+) and possible low lying excited states (1Π, Π3, Σ−3, Σ+3, Δ1, etc.) of ClO− have been investigated using sophisticated ab initio quantum mechanical techniques with large basis sets including diffuse functions. The equilibrium bond distance and vibrational frequency for the ground state (1Σ+) of ClO− are predicted to be 1.688 Å and 660 cm−1 at the coupled-cluster single double (triple) [CCSD(T)]/aug-cc-pVQZ level of theory. The lowest excited singlet state of ClO− is predicted to be the open-shell Π1 state, which is 2.43 eV higher in energy than the ground state, while the lowest triplet state (3Π) of ClO− has a potential with well depth of 0.32 eV. The adiabatic electron detachment energy from ClO− is predicted to be 2.29 eV including zero-point vibrational energy (ZPVE) at the CCSD(T)/aug-cc-pVQZ level of theory. The spin allowed vertical electronic transition (1Σ+–1Π) of ClO− is predicted to be 3.13 eV including ZPVE. The dissociation energies (D0) of ClO− to Cl−(1S)+O(3P), Cl−(1S)+O(1D), and Cl(2P)+O−(2P) are predicted to be 1.40, 3.46, and 3.61 eV, respectively, including ZPVE.
Density-functional theory of linear and nonlinear time-dependent molecular properties
Authors: Sałek Paweł , Vahtras Olav , Helgaker Trygve , Ågren Hans
Published: November 2002

We present density-functional theory for linear and nonlinear response functions using an explicit exponential parametrization of the density operator. The response functions are derived using two alternative variation principles, namely, the Ehrenfest principle and the quasienergy principle, giving different but numerically equivalent formulas. We present, for the first time, calculations of dynamical hyperpolarizabilities for hybrid functionals including exchange-correlation functionals at the general gradient-approximation level and fractional exact Hartree–Fock exchange. Sample calculations are presented of the first hyperpolarizability of the para-nitroaniline molecule and of a porphyrin derived push–pull molecule, showing good agreement with available experimental data.
On the ground states of CaC and ZnC: A multireference Brillouin–Wigner coupled cluster study
Authors: Kerkines Ioannis S. K. , Pittner Jiřı́ , Čársky Petr , Mavridis Aristides , Hubač Ivan
Published: November 2002

We test the recently developed state-specific multireference Brillouin–Wigner coupled cluster (MRBWCCSD) method against the single reference CCSD method by examining theoretically the competing X 3Σ− and Σ−5 states of the (experimentally unknown) isovalent calcium and zinc carbide diatomics (CaC, ZnC). At the CCSD level, CaC is “incorrectly” predicted to have a ground Σ−5 state; however, the MRBWCCSD treatment restores the correct state ordering, and improves significantly the energetics for both molecules. Further comparison with various single- and multireference treatments shows that the latter are absolutely necessary for obtaining meaningful results for the ground states in both molecules.
Solid-state laser induced microwave effects
Authors: Carl Leader J. , Larson C. E. , Treis P. A.
Published: November 2002

Intense laser radiation that is intensity modulated at microwave frequencies produces microwave radiation from a variety of solid-state materials that is band limited by the bandwidth of the laser modulation. An experimental investigation is summarized that provides data on the wavelength, laser intensity, laser modulation frequency, angular distribution, and, in some cases, electric field dependence on the microwave radiation that is produced. When the wavelength of the laser is sufficiently short such that electrons are promoted from the valence to the conduction band, it is clear that the radiation results from the dipole layer radiation resulting from these electrons accelerated in the electric field produced by band bending at the surface or in the PN junction of devices. There appear to be other mechanisms operative in materials such as Ge and ponderomotive forces seem likely. Also poorly understood at this time is the radiation from materials such as ZnS which has a cubic dependence on the incident laser intensity. It is suspected that nonlinear optical effects may be responsible. Although this article only presents experimental results for modulated Q-switched Nd:yttrium–aluminum–garnet laser systems, the authors have obtained entirely consistent results using other laser systems and these results are not presented for the sake of brevity. The production of laser induced microwave effects appears to be a relatively ubiquitous effect in many materials that may provide a useful solid-state diagnostic tool (with improved understanding) or probe of a material’s electromagnetic properties.
Eddy current losses in passive magnetic bearings
Authors: Bouty Olivier
Published: November 2002

Passive magnetic bearings built with permanent magnets, such as NdFeB (neodynium–iron–boron) or SmCo (samarium–cobalt), are very reliable systems when used for industrial applications such as centrifuges or flywheels, as they do not require any electromagnetic coil supply. Nevertheless, during the rotational motion, gyroscopic effects (like precession) or inhomogeneous magnetization can lead to power losses created by eddy currents flowing over the magnetic materials. This article provides a theoretical description and quantification of these phenomena by means of Ampere’s laws. For this purpose, the magnets are assumed to be ring-shaped and axially magnetized. Virtual surface and volume current densities are applied to the calculation of the time-dependent electric field, and consequently to the power loss. Numerical applications are presented for a typical bearing configuration.
Phase behavior of ternary blends of diblock copolymer with homopolymer blends
Authors: Huh June , Jo Won Ho
Published: November 2002

We theoretically predict phase behavior of ternary blends of two different homopolymers (denoted by A and B) and a diblock copolymer consisting of A- and B monomers. Using a mean-field approach of Landau formalism, the phase diagrams are constructed, and the stability of various microstructures, the biphasic coexistence and the triphasic coexistence comprising ordered phases, are discussed. Our theoretical predictions show that swelling of microphase can be observed only when the molecular weight of added homopolymers is comparable to that of the corresponding block of the copolymer, whereas the addition of sufficiently smaller or larger homopolymers leads to a “dilution” of a ordered phase or various phase coexistence between ordered and disordered phase, respectively.
Schmidt number effects on turbulent transport with uniform mean scalar gradient
Authors: Yeung P. K. , Xu Shuyi , Sreenivasan K. R.
Published: November 2002

We study by direct numerical simulations the effects of Schmidt number (Sc) on passive scalars mixed by forced isotropic and homogeneous turbulence. The scalar field is maintained statistically stationary by a uniform mean gradient. We consider the scaling of spectra, structure functions, local isotropy and intermittency. For moderately diffusive scalars with Sc=1/8 and 1, the Taylor-scale Reynolds number of the flow is either 140 or 240. A modest inertial-convective range is obtained in the spectrum, with a one-dimensional Obukhov–Corrsin constant of about 0.4, consistent with experimental data. However, the presence of a spectral bump makes a firm assessment somewhat difficult. The viscous-diffusive range is universal when scaled by Obukhov–Corrsin variables. In a second set of simulations we keep the Taylor-microscale Reynolds number fixed at 38 but vary Sc from 1/4 to 64 (a range of over two decades), roughly by factors of 2. We observe a gradual evolution of a −1 roll-off in the viscous-convective region as Sc increases, consistent with Batchelor’s predictions. In the viscous-diffusive range the spectra follow Kraichnan’s form well, with a coefficient that depends weakly on Sc. The breakdown of local isotropy manifests itself through differences between structure functions with separation distances in directions parallel and perpendicular to the mean scalar gradient, as well as via finite values of odd-order moments of scalar gradient fluctuations and of mixed velocity-scalar gradient correlations. However, all these indicators show, to varying degrees, an increasing tendency to isotropy with increasing Sc. The moments of scalar gradients and the scalar dissipation rate peak at Sc≈4. The intermittency exponent for the scale-range between the Kolmogorov and Batchelor scales is found to decrease with Sc, suggesting qualitative consistency with previous dye experiments in water [Sc=O(1000)].
Theoretical study of the OH/OD stretching regions of the vibrational spectra of ice Ih
Authors: Wójcik Marek J. , Szczeponek Krzysztof , Ikeda Susumu
Published: November 2002

In this paper we present results of our theoretical studies of the vibrational spectra of ice Ih in the stretching mode frequency range. They include simulation of the infrared and Raman spectra for the OH and OD stretching regions, the effects of a full range of isotopic dilution on the spectra (including polarized Raman spectra) and computational modeling of the observed influence of each dilution step on the properties of vibrationally excited states and on the infrared and Raman spectra. In our calculations we included effects of frequency lowering due to hydrogen bonding, and of intramolecular and intermolecular coupling between bonds. In the crystalline isotopomers the properties of the vibrationally excited states and of the spectra are determined by a complex interplay between the size distributions of the embedded clusters and the intermolecular and intramolecular couplings.
The binary system triethylamine-water near its critical consolute point: An ultrasonic spectrometry, dynamic light scattering, and shear viscosity study
Authors: Behrends Ralph , Telgmann Thomas , Kaatze Udo
Published: November 2002

Ultrasonic attenuation spectra between 100 kHz and 500 MHz, mutual diffusion coefficients and shear viscosities of the triethylamine/water mixture of critical composition have been measured at various temperatures near the critical one. The broadband ultrasonic spectra reveal two relaxation terms with discrete relaxation time and a term that is subject to a broad relaxation time distribution. The former have been discussed to be due to a protolysis reaction and a structural isomerization. The latter term has been evaluated in the light of the Bhattacharjee–Ferrell dynamic scaling theory, relating the sonic spectrum to fluctuations in the local mixture concentrations. The relaxation rate of the Bhattacharjee–Ferrell term follows power law behavior. However, its amplitude (Γ0=45×109 s−1) is considerably smaller than that derived from the dynamic light scattering and shear viscosity measurements (Γ0=96×109 s−1). This result is assumed to be due to a shear viscosity relaxation. Using density and heat capacity measurements from the literature, the adiabatic coupling constant g of the triethylamine/water system has been derived from the amplitude of the Bhattacharjee–Ferrell term in the ultrasonic spectra and from a thermodynamic relation as well. Again, a discrepancy is found. The ultrasonic spectra yield g=0.19, whereas g=0.98 follows otherwise. This difference in the g values is taken as an indication of the limitations of the Bhattacharjee–Ferrell model. It had been derived assuming a small amplitude in the singular part of the heat capacity, a precondition which is clearly not fulfilled with the triethylamine/water system.
Mass spectrometry in weakly ionized plasmas using a Gifford–McMahon cryocooled superconducting magnet
Authors: Murakami T. , Kaneko T. , Terashima J. , Hatakeyama R. , Murase S. , Shimamoto S.
Published: November 2002

Direct mass spectrometry has been successfully conducted even at a high argon gas pressure of the order of 10−3 Torr, using a Gifford–McMahon cryocooled superconducting magnet with a magnetic flux density as high as 2 T. A numerical model including collisional effects has been proposed to describe the performance of an omegatron. The intensity of ion current and the mass resolution as functions of pressure and magnetic flux density have been obtained experimentally in the case of argon plasma and compared with those calculated numerically. Collisional effects on the omegatron performance were clarified by this comparison. Although the mass resolution deteriorates under the high-pressure condition, it is predominantly improved in proportion to the magnetic flux density. The collisional effects and the magnetic flux density dependence of the mass resolution at high pressure are clearly explained by the present numerical model.
Dynamic sheath model at pulsed-biased insulating substrates
Authors: Dai Zhong-Ling , Wang You-Nian
Published: November 2002

Characteristics of collisionless pulse-biased sheaths are studied with a one-dimensional fluid model coupled up to an equivalent circuit model. All the time-dependent terms are included in the ion fluid equations to ensure that the model can describe the sheath dynamics over a wide range of pulse frequency, especially in the intermediate pulse frequency range. The equivalent circuit model gives the instantaneous relationship between the sheath thickness and the surface potential at an insulating substrate placed on the pulse-biased electrode. The spatiotemporal variations of the potential, ion density and electron density inside the sheath are shown numerically. Additionally, the ion energy distributions arriving at insulating substrates and the charge density accumulated on insulating substrates are calculated with the model. It is shown that some parameters such as the pulse frequency, pulse duty ratio, and amplitude of the pulse voltage applied on the electrodes play an important role not only in determining the characteristics of the sheath dynamics and the ion energy distributions at insulating substrates but also in remedying the “surface charging effect.”
Hybrid modeling network for a helium–argon–copper hollow cathode discharge used for laser applications
Authors: Bogaerts Annemie , Gijbels Renaat
Published: November 2002

A hybrid modeling network, consisting of several Monte Carlo and fluid models, is developed for a hollow cathode glow discharge in a mixture of helium and argon, with copper as the cathode material. The species considered in the models are the helium and argon gas atoms, electrons, He+, He2+, Ar+, and Ar2+ ions, He and Ar metastable atoms, fast He and Ar atoms, and sputtered Cu atoms and Cu+ ions. The modeling network is applied to typical laser conditions. The results of the model, presented in this article, include the electric potential distribution, the density profiles of the various plasma species, and the relative contributions of the various production and loss mechanisms for the plasma species. The model gives us more insight into the plasma behavior, and is therefore useful for optimization of the discharge efficiency for laser applications.
Control of molecular processes by a sequence of linearly chirped pulses
Authors: Nagaya Kuninobu , Teranishi Yoshiaki , Nakamura Hiroki
Published: November 2002

A new scheme of controlling molecular processes by a sequence of linearly chirped pulses is proposed and is applied to selective excitation of an energy level among closely lying ones and to complete electronic excitation of a diatomic molecule. The basic idea is quite different from the conventional ones utilizing chirped pulses in the sense that the present one does not rely on the idea of adiabatic rapid passage at all, but tries to control basic nonadiabatic transitions explicitly. Control of molecular processes can be achieved by controlling nonadiabatic transitions among Floquet (or dressed) states with use of the interference effects. The scheme can be formulated with use of the analytical theories of nonadiabatic transitions, and the proper control parameters can be estimated theoretically. Numerical demonstrations are provided to confirm the robustness of the method in comparison with the other conventional ones. Namely, the present scheme is shown to be stable against the variation of pulse area, complete and selective in population transfer, and fast to accomplish the transition. It is expected that the method can be applied to general multilevel systems and various types of wave packet dynamics. Its experimental realizability can also be expected, since linear chirping can now be relatively easily realized and manipulated.
Phase behavior of mixtures of colloidal platelets and nonadsorbing polymers
Authors: Zhang Shu-Dong , Reynolds Paul A. , van Duijneveldt Jeroen S.
Published: November 2002

The phase behavior of a model system of colloidal platelets and nonadsorbing polymers is studied using computer simulations and perturbation theory. The equation of state for the pure platelet reference system is obtained by Monte Carlo simulations, and the free volume fraction accessible to polymers is measured by a trial insertion method. The free volume fraction is also calculated using scaled particle theory. Subsequently, the phase diagram for platelet–polymer mixtures is calculated. For a platelet aspect ratio L/D=0.1 and a polymer to platelet size ratio d/D>0.2, we observe coexistence between two isotropic phases with different densities. For smaller polymers d/D<0.2, only one isotropic phase is present. At higher platelet concentrations nematic and columnar phases are found. Where possible, direct simulations of plate–polymer mixtures, namely Gibbs ensemble simulation and Gibbs–Duhem integration, are used to check the validity of the perturbation approach. Qualitatively similar results are obtained for platelets of L/D=0.05. The results are compared with existing theoretical data as well as with experimental observations.
Turbidity of the liquid–liquid mixture perfluoroheptane and 2,2,4-trimethylpentane near the critical point
Authors: Braganza Clinton I. , Jacobs D. T.
Published: November 2002

The turbidity of the liquid–liquid mixture perfluoroheptane and 2,2,4-trimethylpentane (also known as iso-octane) has been measured and used to determine the correlation length amplitude ξ0. By measuring the ratio of the transmitted to incident light intensities over three decades in reduced temperature, we are able to determine that ξ0=0.253±0.005 nm. This value differs significantly from that reported in the literature. The earlier literature value for ξ0, when combined with the amplitude A+ determined in a recent heat capacity measurement on this system, produced the two-scale-factor universality constant X=A+ξ03/kB=0.009±0.002, which was not consistent with other experiments and theories that had found a value between 0.018 and 0.020. However, when we combine the value of ξ0 determined in this experiment with the amplitude A+ then the two-scale-factor universality constant X=0.020±0.002, which is quite consistent with other determinations.
Pure rotational spectra of the Ar–HN2+ and the Kr–HN2+ ionic complexes
Authors: Seki Kouji , Sumiyoshi Yoshihiro , Endo Yasuki
Published: November 2002

Pure rotational spectra of ionic complexes, Ar–HN2+ and Kr–HN2+, have been observed using a Fourier transform microwave spectrometer combined with a pulsed-discharge nozzle, where Kr–HN2+ has been detected for the first time. The rotational constants, the centrifugal distortion constants, and the nuclear quadrupole coupling constants of the two nitrogen nuclei have been determined by least squares fittings for various isotopomers. The complexes have been concluded to have a linear proton-bound form, with the Ar–H distance in Ar–HN2+ to be 1.864 Å and the Kr–H distance in Kr–HN2+ to be 1.948 Å, respectively. Intermolecular stretching frequencies are estimated to be 199.2 cm−1 for Ar–HN2+ and 198.7 cm−1 for Kr–HN2+, respectively. Comparison of the results of Rg–HN2+ (Rg=Ar, Kr) with those of Rg–HCO+ indicates that Rg–HN2+ complexes have substantially stronger Rg–H interactions than those of Rg–HCO+. Furthermore, the derived nuclear quadrupole coupling constants suggest that there exists a sizable amount of proton transfer effect toward the Rg side in Rg–HN2+.