Miracle-dz/UniFAR-FTUs huggingface dataset:
Magnetoresistance of Antiferromagnetic Metals Due to s-d Interaction

A simple expression for the magnetoresistance of the antiferromagnetic metals due to the electron-spin scattering by the s - d interaction is obtained using the molecular field approximation for the spin system. The expression includes the ferromagnetic case. It is shown that in the antiferromagnetic case the positive magnetoresistance appears below the transition point, in contrast to the negative-magnetoresistance in the case of the para or ferromagnetic case. In the ferromagnetic case the negative magnetoresistance shows a deep and finite valley at the transition point, which is consistant with the experiments of the ferromagnetic rare-earth metals such as Gd and Tb.
Fully Proportional Representation

Even though voters can have complex preferences over multiple candidates or parties, all extant electoral systems provide political representation based solely or primarily on voters' first preferences. I present a new concept of proportional representation that takes account of voters' preferences over the full list of alternatives—fully proportional representation (FPR)—and schemes for its implementation. I outline a “pure” FPR scheme, but because this scheme would have several undesirable features when used by real voters, I also discuss modifications that account for these difficulties. Although there are a variety of interpretations of the role played by voting in democracy, several can be shown to suggest FPR as a normative ideal. Fully proportional representation provides us with new ways to conceptualize existing electoral systems, a new standard against which alternative systems can be evaluated, and several feasible alternatives for approximating this new ideal.
Climate response to aerosol injection at different stratospheric locations

The effect of altitude and latitude of sulfate aerosol injection into the stratosphere on climate is studied with Earth system model INMCM. The model includes the general circulation of the atmosphere and oceans as well as a sulfate aerosol component, and is used to determine the most effective injection scenario for reducing changes in temperature and precipitation at a global level and in the Arctic. Copyright © 2011 Royal Meteorological Society
Statistical characterization of circulation patterns and direction of turbulent flow over a waveform structure

The objective of this paper is to analyze statistically the turbulence characteristics of flow over an artificial waveform geometry in an open channel, using velocity data collected by 3‐D acoustic doppler velocimeter (ADV). The joint distribution of velocity fluctuations have been studied and modeled using multivariate normal distribution, and its effectiveness is analyzed in the light of explaining turbulent bursting events, like sweeping and ejection. The relationship between the randomness in the directional variations of the 3‐D velocity fluctuations and the intensity of circulation has been studied. We have exploited this relationship and used it in conjunction with the principles of statistical clustering for splitting the region of flow, into different spatially connected segments based on circulation patterns. Directional data analysis has been adopted to visualize the flow pattern over the entire test section, in particular, the circulation bubbles in the region of separated flow. Copyright © 2006 John Wiley & Sons, Ltd.
The uniform circular motion with invariable normal spin of a rigidly and uniformly electrified sphere, IV

In order to exhibit clearly and fully the possibilities inherent in classical electrodynamics when it is developed rigorously without approximations or unnecessary restrictions I have in this paper worked out completely the case in which the centre of the sphere describes a circle with any uniform speed less than that of light whilst it is spinning about a diameter normal to the plane of the circle with an invariable angular velocity unrestricted in magnitude or sense. It is to be noted that, although the speed of the centre is assumed for the sake of simplicity to be less than that of light, that of points on the surface of the sphere (other than the ends of the axis of spin) can be as large as we please. In §§ 2–5 general expressions for the tangential and normal force constituents and the couple constituent of the total reaction on the sphere of its own electromagnetic field are obtained from the general expressions given in paper III (§ 8), and the resulting equations of motion are written down (cf. (2·1)–(2·3) and (5·7)). There are two points to be noticed: (1) the tangential and normal force constituents are quadratic polynomials in the spin p with coefficients depending on the speed cβ of the centre and the radius R of its orbit, whilst the couple constituent is linear in p ; these results are true for any orbit with invariable spin. (2) The couple is found in § 5 to vanish identically, i. e. for all values of p, β and R , in the case of a circular orbit, owing to its symmetry with respect to a diameter; for this reason the result is probably peculiar to this class of orbit.
Infall of galaxies into the virgo cluster and some cosmological constraints

A family of mass models have been developed to describe the observed infall of galaxies in the Virgo Southern Extension toward the Virgo Cluster. The requirement that the mass models also explain the motion of our Galaxy with respect to the Virgo Cluster provides some constraints of cosmological interest. If the age of the universe is 10 15 Gyr, there is already (too much) much mass at small radii, as implied both by the virial analysis of the cluster and the infall model for the galaxies close to the cluster, to explain the motion of our Galaxy. If it is insisted that the universe is older than this limit, then a tractable conclusion is that the cosmological constant is positive. With the mass-age models and a census of the distribution of galaxies near the Virgo Cluster, it is possible to estimate the near-future accretion rate of galaxies into the central cluster.
Properties of zeros of discretised system using multirate input and hold

The paper investigates the proprieties of limiting zeros of a discrete-time system discretised by the use of multirate input and hold. The stability conditions of the limiting zeros for sufficiently small sampling periods are derived in the case that the relative degree of a continuous-time system is equal to two or three. It is also shown that the intersample behaviour arising from the multirate input can be localised by appropriately selecting the design parameters based on the stability condition of the zeros.
Three-dimensional atom localization in a five-level M-type atomic system

By using three mutually perpendicular standing-wave fields, we propose a scheme for three-dimensional (3D) subwavelength atom localization in a five-level M-type atomic system. Based on the electromagnetically induced transparency, position probability distribution of the atom in 3D space could be determined via measuring the probe absorption which is proportional to the filter function. It is shown that patterns of 3D atom localization depends sensitively on the coupling schemes of the standing-wave fields. When the standing-wave fields couple three different transitions, the same atom localization patterns are formed in the eight subspaces of the 3D space. While all the standing-wave fields are applied on one transition, we can realize different atom localization patterns in the eight subspaces. From the view of the xy plane, various symmetric or asymmetric atom localization patterns could be formed at different z positions by adjusting the parameters of the laser fields.
Micromagnetism and the microstructure of high-temperature permanent magnets

Sm2(Co,Cu,Fe,Zr)17 permanent magnets with their three-phase precipitation structure (cells, cell walls, and lamellae) show two characteristic features which so far are difficult to interpret but which are the prerequisites for high-temperature applications: (1) The hard magnetic properties only develop during the final step of the three-step annealing procedure consisting of homogenization, isothermal aging, and cooling. (2) Depending on the composition and on the annealing parameters, the temperature dependence of the coercivity can be easily changed from the conventional monotonic to the recent nonmonotonic behavior showing coercivities up to 1T even at 500K. The magnetic hardening during cooling is due to the fact that the cell walls order chemically and structurally during the cooling process. From an analysis of electron diffraction patterns of the superimposed structures existing before and after cooling it could be proven that a phase transition from a phase mixture of defective phases 2:17, 2:7, a.
Optical Properties of Aggregated Silver Films

For interpreting the optical properties of aggregated metal films, a modification of Schopper’s model is proposed, based on the assumption that an aggregated film consists of particles in the shape of rotational ellipsoids. Instead of the distribution of the depolarizing factor f in gaussian fashion, which is assumed in Schopper’s model, the logarithmic normal distribution of the axial ratio γ of the ellipsoidal particles was assumed and the parameter σ (standard deviation of the distribution function) was introduced. Besides, the contributions of the dipole interaction between particles and the size-dependent optical constants of the particles were taken into account. Using this modified model, the observed values of silver films continuously measured by ellipsometry during deposition were analyzed and the two parameters, the mean axial ratio γ¯ and the standard deviation σ, were obtained as functions of film thickness. The results showed that as film grows, both γ¯ and σ increase monotonically. Good coincidence of the observed and the calculated absorption spectra from our model seems to show the validity of our modification.
ON THE PROPAGATION OF FREQUENCIES AND ENERGY IN CERTAIN TYPES OF OCEANIC AND ATMOSPHERIC WAVES

Abstract In this paper the energy and frequency propagation in certain types of plane waves in the atmosphere and in the ocean are investigated, these wave trains being characterized by the property that frequency and wave number are slowly varying functions of the space coordinate and time. The assumption is made that wave crests are conserved, and on this basis a simple kinematic relationship between frequency and wave number is established. Wave trains for which the physical theory results in a frequency equation of such a character that phase velocity and wave length uniquely determine each other are then found to possess a characteristic group velocity, and it is shown that frequencies (and hence group velocities) are propagated with this characteristic group velocity. In the more general case the frequency equation resulting from the physical theory is found to contain a correction term which is an explicit function of the space coordinate and time. In that case observers travelling with the convent.
Special issue on Pre-college nanoscale science, engineering, and technology learning

In the year 2000, U.S. President William J. Clinton established the National Nanotechnology Initiative (NNI), a federal government research and development initiative involving 20 federal departments and independent agencies, whose overarching vision is “a future in which the ability to understand and control matter at the nanoscale leads to a revolution in technology and industry that benefits society” ([1], p. 5). The NNI would be one of the many nanoscale science, engineering, and technology (NSET) initiatives, centers, collaborations, and networks developed globally, on nearly every continent, during the early years of the new millennium. From university programs to multi-national networks, by the end of the first decade of the 21st century, it was clear that nanotechnology was emerging as one of the most promising and rapidly expanding fields of research and development worldwide. It would not be long before scientists, science educators, engineers, and policy makers began advocating for NSET concepts to be introduced in the K-12 education system. Mihail C. Roco, Senior Advisor for Nanotechnology at the U.S. National Science Foundation, speculated on the emergence of nanoscale concepts in K-12 education (and beyond) and emphasized the urgent need for science and engineering education to focus on the development of interconnected, interdisciplinary knowledge:
ELEMENT ABUNDANCES IN ALGOL-TYPE BINARIES.

The results of an abundance analysis of both the primaries and secondaries of six eclipsing binary stars are presented. The analysis was done by adjusting the parameters used to generate synthetic spectra until the best fit with the observed spectra was obtained. The secondaries of three "classical" Algol-type binaries, U Cep, TT Hya, and ZZ Cuc, were found to be very slightly metal deficient in agreernent with photometric results. The subgiant secondaries of RS CVn and RW UMa, which do not fill their Roche lobes, are found to be moderately metal deficient. The secondary of the widely separated supergiant system, RZ Oph, shows no metal deficiency. All of the primaries are either normal or very slightly metal rich. Several theories of binary-star evolution are considered, but none explain these results satisfactorily. Key words: Algol binaries - abundance analysis
Complex ray interpretation of reflection from concave-convex surfaces

Reflection from a smooth target with inflection points, when investigated by the physical optics method, reveals far-zone contributions arising from real and complex stationary points. The former represent conventional specularly reflected real-ray fields whereas the latter, which are nonspecular in real space, can be interpreted as complex-ray fields reflected specularly from the complex extension of the scatterer surface. To explain the nonspecular contributions, the complex stationary point fields are regarded as specular reflections of complex incident rays from the analytic extension of the boundary into a complex coordinate space. It is verified that this construction using complex geometrical optics is in complete agreement with physical optics asymptotics and that the complex reflection points for far-zone fields lie near the concave-to-convex transitions on the physical contour. Numerical results supporting the validity of this assertion are provided. It is concluded, therefore, that a complete ray theory of reflection from the illuminated portion of a smooth object with inflection points must include specularly reflected real as well as complex rays, with the latter originating from the complex extension of the surface contour. >
Some Bulk Properties of Cumulus Ensembles Simulated by a Cloud-Resolving Model. Part II: Entrainment Profiles

Abstract As a continuation of the effort to develop an improved cloud model of cumulus parameterization, this study investigates entrainment profiles of the cumulus ensembles simulated by a cloud-resolving model (CRM). The simulated saturated updrafts are separated into different categories according to their maximum heights. Entrainment characteristics of each category are then inferred from cloud mass flux and moist static energy profiles. It is found that all categories of saturated updrafts tend to have the most significant entrainment at lower levels and near cloud top. Moreover, the details of the entrainment characteristics are not sensitive to vertical wind shear but are primarily determined by large-scale thermodynamic fields. The dependence of entrainment characteristics on large-scale thermodynamic fields can be interpreted as a manifestation of a relationship between cloud buoyancy and entrainment rate. With these findings, a formula is proposed to describe entrainment profiles of the cloud sp.
Heat Transfer During Forced Convection Boiling of R-12 Under Swirl Flow

This work is an experimental investigation of heat transfer augmentation in a horizontal R-12 evaporator, continuing an earlier study [1] by the authors on swirl flow pressure drops. Twisted tapes were used to create swirl motion during the flow boiling inside an evaporator tube of 10 mm i.d. Average heat transfer coefficients have been determined for 60 runs corresponding to three heat fluxes, five mass velocities, and four twist ratios. Swirl flow heat transfer coefficients have been found, in general, to be greater than the corresponding plain flow values, but the degree of enhancement varies depending on the test conditions and the twist ratio of the inserted tape. An empirical correlation which predicts the average swirl flow heat transfer coefficients within ± 30 percent of the experimentally observed values has been successfully developed.
Post-asymptotic giant branch nonradial instability strips

Stability analyses are performed for nonradial g(+)-mode pulsations of postasymptotic AGB stellar models to determine the location of their pulsational instability strips in the Hertzsprung-Russell diagram. Stellar models are analyzed that are assumed to have undergone a major mass loss event either near the tip of the AGB or shortly thereafter and, therefore, consist of a 50-percent carbon 50-percent oxygen core. Their mass is 0.6 solar mass, which is in good agreement with the peak of the observed distribution of white dwarf masses. The results are compared both to the observed planetary nebula nuclei variables and the hot pulsating DO variables. An analysis is also presented of the stability of DB white dwarfs, which have much deeper and stronger convection zones, and an instability strip is found between about 18,000 and 26,000 K approximately as observed for the known variable stars. 51 refs.
Infrared Spectroscopy of Jupiter's Atmosphere after the A and E Impacts of Comet Shoemaker–Levy 9

Abstract Infrared spectra of Jupiter's atmosphere were obtained with the infrared spectrometer (IRS) on the 1.5-m telescope at the Cerro Tololo Inter-American Observatory (CTIO) during the first 2 days of the impacts of the fragments of Comet Shoemaker–Levy 9 (1993e). We monitored 3.51 ± 0.17 μm radiation from the impact areas, undisturbed areas, and auroral regions of Jupiter after the A and E impacts. The strong emission of a portion of the P-branch of the ν 3 band of CH 4 was detected on the A impact area 4 hr after the impact. H + 3 emissions are found to be decreased at the A and E impact sites after 4 hr and 10 hr 50 min of the impacts, respectively, compared with undisturbed areas at the same latitude. The temperatures of the southern H + 3 aurora were normal within the first several hours following the A and E impacts.
Linear mode conversion of Langmuir/z mode waves to radiation: Averaged energy conversion efficiencies, polarization, and applications to Earth's continuum radiation

Linear mode conversion (LMC) is the linear transfer of energy from one wave mode to another in a density gradient. It is relevant to planetary continuum radiation, type II and III radio bursts, and ionospheric radio emissions. This paper analyzes LMC by calculating angle‐averaged energy (ε) and power (εp) conversion efficiencies in both 2‐D and 3‐D for Langmuir/z mode waves (including upper hybrid waves for perpendicular wave vectors) converting to free‐space radiation in turbulent plasmas. The averages are over the distributions of the incoming Langmuir/z mode wave vectors k, density scale lengths L, and angles α and δ, where α is the angle between k and the background magnetic field B0 and δ is the angle between the density gradient ∇N0 and B0. The results show that the averaged and unaveraged conversion efficiencies are dependent on γβ, where γ is the adiabatic index and β is related to the electron temperature Te by β = Te/mec2. The averaged energy conversion efficiencies are proportional to γβ in 2‐D and to (γβ)3/2 in 3‐D, whereas the power conversion efficiencies are proportional to (γβ)1/2 in 2‐D and γβ in 3‐D. The special case of a perpendicular density gradient (δ≈90°) is considered and used to predict the conversion efficiencies of terrestrial continuum radiation (TCR) in three known source regions: the plasmapause, magnetopause, and the plasma sheet. The observed energy conversion efficiencies are estimated and are found to be consistent with the 2‐D and 3‐D predicted efficiencies; importantly, these results imply that LMC is a possible generation mechanism for TCR. The polarization of TCR is also predicted: TCR should be produced primarily in the o mode at the plasmapause and in both the o and x modes at the magnetopause and plasma sheet. These predictions are consistent with previous independent predictions and observations.
Enhanced light emission from an organic photonic crystal with a nanocavity

An organic photonic crystal (PC) with a nanocavity has been fabricated on a SiO2 membrane with air holes. The emission peak caused by the resonant mode of the nanocavity was clearly observed from the nanocavity area of the PC. The emission peak corresponded to degenerated dipole modes from comparison between measured and calculated results. Modification of a nanocavity caused the peak splitting of dipole modes and the appearance of a peak corresponding to a hexapole mode. The emission peak with a quality factor of about 1000 was obtained from a PC with a modified nanocavity.
Study of Two BeppoSAX Observations of GX 340+0

We present the results of two BeppoSAX broad band (0.1–200 keV) observations of the Z-source GX 340+0 comparing our results to those of a previous observation of the source. From the color–color diagram we selected three zones and extracted the source energy spectrum from each zone. We find that the model, composed by a blackbody plus a Comptonized component, absorbed by an equivalent hydrogen column of ~6 × 10 22 cm −2 , well fits the spectra in the energy range below 30 keV. At higher energies a power law component with photon index of 2.5 is observed. The associated flux decreases going from the horizontal branch to the flaring branch of the Z-track.
Cepheus OB2: Disk Evolution and Accretion at 3-10 Myr

We present the results of MMT observations of young stars for our study of protoplanetary disks at ages 1–10 Myr in two young clusters located in the Cepheus OB2 region: Trumpler 37 (embedded in the H II region IC 1396) and NGC 7160. Using low-resolution optical spectra from the Hectospec multifiber spectrograph, we have tripled the number of known low-mass cluster members, identifying ∼130 new members in Tr 37 and ∼30 in NGC 7160. We use indicators of youth (Li absorption at 6707 Å) and accretion/chromospheric activity (Hα emission) to identify and classify the low-mass cluster members. We derive spectral types for all the low-mass candidates and calculate the individual extinctions and the average over the clusters. With the extended member samples, we estimate the disk fraction in the clusters, finding that ∼40% of the low-mass stars in Tr 37 are actively accreting, whereas only 1 of the ∼55 low-mass stars in NGC 7160 shows indications of accretion. Optical photometry and theoretical isochrones are used to determine the age of the cluster members, confirming the estimates of ∼4 Myr for Tr 37 and ∼10 Myr for NGC 7160. Accretion rates in Tr 37 (∼10-8 M⊙ yr-1 on average) are derived from U-band photometry. We find that only ∼50% of the accreting stars have near-IR excesses (from 2MASS), which could be due to the geometry of their disks or be an indication dust of settling/grain growth. Finally, we study the high- and intermediate-mass members of the clusters. With the extended member list, we revise the spatial distribution of stars with disks. Our results are crucial for interpreting Spitzer Space Telescope studies of accretion disks at the ages of planet formation (3–10 Myr).