Fine structure of the parathyroid gland of the laying hen
White Leghorn laying hens parathyroid glands fine structure from electron microscopic studies, noting electron dense membrane bound mature secretory granules in cytoplasm
Nevalainen, T.↗
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Sodium super 2P fine-structure transitions in collisions with helium
Closed coupled partial wave calculation of cross section for fine structure transitions in Na in collisions with He
Dalgarno, A.↗
A note on chromospheric fine structure at active region polarity boundaries
High resolution H-alpha photographs for studying chromospheric fine structure at active region polarity boundaries
Prata, S. W.↗
Fine-structure lines and elemental abundances in the Orion Nebula
Infrared observations of the forbidden fine-structure lines of Ne II at 12.81 microns, S IV at 10.51 microns, and Ar III at 8.99 microns in the Orion Nebula are presented. These measurements are combined with optical observations of forbidden Ne III, S II, S III, O II, and O III to derive total elemental abundances of neon, sulfur, and oxygen, Ne/H = 7.91, S/H = 7.34, and O/H = 8.60, which are very similar to solar abundances. While the commonly employed ionization correction formula scheme is found to work satisfactorily for neon, the method overcompensates for the abundance of S(3+) and leads to a higher sulfur abundance than is actually present, though the net discrepancy in the elemental abundance of sulfur in Orion is small.
Lester, D. F.↗
Oscillator Strengths for Fine-Structure Transitions in S III
Oscillator strengths and transition probabilities for transitions among the fine-structure levels of the terms belonging to the 3s(sup 2)3p(sup 2), 3s3p(sup 3), 3s(sup 2)3p3d, 3s(sup 2)3p4s, 3s(sup 2)3p4p, and 3s(sup 2)3p4d configurations of S III are calculated using extensive configuration-interaction wave functions. The relativistic effects in intermediate coupling are incorporated by means of the Breit-Pauli Hamiltonian. Small adjustments to the diagonal elements of the Hamiltonian matrices have been made so that the energy splittings are as close as possible to the experimental values. The present results are compared with other available calculations and experiments.
Tayal, S. S.↗
Fine structure of the solar transition region - Observations and interpretation
An evaluation is conducted of recent high spatial resolution observations of the solar transition region and temperature minimum, in the form of UV spectra and spectroheliographs from both sounding rockets and the Spacelab 2 flights of the High Resolution Telescope and Spectrograph (HRTS). Attention is given to the solar atmosphere structure implications of the HRST's observational results. The inclusion of fine structure in conjectures concerning the transition region affects the plausibility of 1D average models of the solar atmosphere, as well as the determination of temperature gradients, possible nonradiative-heating mechanisms, and the comparison of transition region structures with corresponding observations of the photosphere and corona.
Cook, J. W.↗
Fine structure in the α decay of $^{179}$Hg and $^{177}$Au
Abstract The$$\upalpha $$ α -decay fine structure of$$^{179}$$ 179 Hg and$$^{177}$$ 177 Au was studied by means of decay spectroscopy. Two experiments were performed at the Accelerator Laboratory of the University of Jyväskylä (JYFL), Finland, utilizing the recoil separator RITU and a digital data acquisition system. The heavy-ion induced fusion-evaporation reactions$$^{82}_{36}$$ 36 82 Kr + $$^{100}_{44}$$ 44 100 Ru and$$^{88}_{38}$$ 38 88 Kr + $$^{92}_{42}$$ 42 92 Mo were used to produce the$$^{179}$$ 179 Hg and$$^{177}$$ 177 Au nuclei, respectively. Studying the evaporation residues (ER, recoils)-$$\alpha _1$$ α 1 -$$\alpha _2$$ α 2 correlations and$$\upalpha $$ α -$$\gamma $$ γ coincidences, a new$$\upalpha $$ α decay with E$$_\alpha $$ α = 6156(10) keV was observed from$$^{179}$$ 179 Hg. This decay populates the (9/2$$^-$$ - ) excited state at an excitation energy of 131.3(5) keV in$$^{175}$$ 175 Pt. The internal conversion coefficient for the 131.3(5) keV transition de-exciting this state was measured for the first time. Regarding the$$^{177}$$ 177 Au nucleus, a new$$\upalpha $$ α decay with E$$_\alpha $$ α = 5998(9) keV was observed to populate the 156.1(6) keV excited state in$$^{173}$$ 173 Ir. Two de-excitation paths were observed from this excited state. Moreover, a new 215.7(13) keV transition was observed to depopulate the 424.4(13) keV excited state in$$^{173}$$ 173 Ir. Properties of the$$^{179}$$ 179 Hg and$$^{177}$$ 177 Au$$\upalpha $$ α decays were examined in a framework of reduced widths and hindrance factors. For clarity and simplicity, the spin and parity assignments (e.g.$$J^{\pi }$$ J π ) are presented without brackets throughout the text.
Physics↗
Fine-structure absorption measurements of bulk rare-earth IG single crystals by reflectivity techniques
Absorption transition fine structure measurements for bulk rare earth garnets single crystals using reflectivity techniques
Grismore, F. L., Jr.↗
Gravity field fine structure estimation techniques for a spaceborne gravity gradiometer
Use of standard estimation techniques to recover geopotential fine structure from gradiometer data requires the adjustment of small subsets of parameters while constraining others to their a priori values in order to minimize the computational load. Here, gravitational anomalies are selected as a parametrization of the gravity field which permits such an approach. Techniques coupled with numerical results for a spaceborne gravity gradiometer mission simulation are described which demonstrate that if a satellite is in a polar/circular orbit at an altitude of 160 km, 1 deg mean free air gravity anomalies can be recovered to an accuracy of 0.4 mgal, where 1 mgal = 0.001 cm/sq s.
Kahn, W. D.↗
Extended fine structures in the electron energy loss spectrum of InAs
The possibility of using electron energy loss fine structure (EELFS) for the characterization of thin pseudomorphic quantum wells of InAs and GaAs(100) is investigated. It is shown that the EELFS technique can yield reliable radial distribution functions for bulk InAs, provided beam-induced sample degradation is controlled stringently. Additional improvements in the data collection procedures, including better control of the sample condition, are required as well as more detailed work on separating contributions from multiple edges in the data analysis.
Schowengerdt, F. D.↗
Observations of the infrared fine-structure lines of S III at 18.71 and 33.47 microns in four H II regions
Infrared fine-structure lines provide a particularly useful probe of ionized nebulae. The present investigation is concerned with measurements of the forbidden S III lines at 18.71 and 33.47 micrometers for four H II regions, S158A, S158G, G75.84+0.4, and W3 IRS 1. These lines are used to estimate densities, and comparisons are made with rms densities determined from radio observations to evaluate the importance of clumping. For the case of the optical H II region S158A, comparisons are made with both optical and forbidden O III line determinations of the density. The reported observations were made using a dual-grating, liquid-helium-cooled spectrometer containing a three-element Si:Sb detector array and a three-element Ge:Ga detector array. It is found that clumping is important in the cases of G75.84+0.4, W3 IRS 1, and M42. These three H II regions have filling factors of 0.024, 0.09, and 0.03, respectively.
Herter, T.↗
The direct measurement of the 3 3P0-3 3P1 fine-structure interval and the gJ-factor of atomic silicon by laser magnetic resonance
The J - 1 fine structure interval and the g-factor of the 3P1 state have been determined with high precision in the present laser magnetic resonance measurements of the ground 3p2 3P multiplet of atomic Si. Delta-E(3P1-3P0) = 2,311,755.6(7) MHz, and gJ(3P1) = 1.500830(70). Single-configuration calculations of gJ for 3P1 and 3P2 yield a value for the latter which, at 1.501095, is noted to differ by an unexpectedly large margin from the experimental value.
Evenson, K. M.↗
Fine Structure in the Secondary Electron Emission Peak for Diamond Crystal with (100) Negative Electron Affinity Surface
A fine structure was discovered in the low-energy peak of the secondary electron emission spectra of the diamond surface with negative electron affinity. We studied this structure for the (100) surface of the natural type-IIb diamond crystal. We have found that the low-energy peak consists of a total of four maxima. The relative energy positions of three of them could be related to the electron energy minima near the bottom of the conduction band. The fourth peak, having the lowest energy, was attributed to the breakup of the bulk exciton at the surface during the process of secondary electron emission.
Asnin, V. M.↗
The Effects of Instrumental Elliptical Polarization on Stellar Point Spread Function Fine Structure
We present procedures and preliminary results from a study on the effects of instrumental polarization on the fine structure of the stellar point spread function (PSF). These effects are important to understand because the the aberration caused by instrumental polarization on an otherwise diffraction-limited will likely have have severe consequences for extreme high contrast imaging systems such as NASA's planned Terrestrial Planet Finder (TPF) mission and the proposed NASA Eclipse mission. The report here, describing our efforts to examine these effects, includes two parts: 1) a numerical analysis of the effect of metallic reflection, with some polarization-specific retardation, on a spherical wavefront; 2) an experimental approach for observing this effect, along with some preliminary laboratory results. While the experimental phase of this study requires more fine-tuning to produce meaningful results, the numerical analysis indicates that the inclusion of polarization-specific phase effects (retardation) results in a point spread function (PSF) aberration more severe than the amplitude (reflectivity) effects previously recorded in the literature.
high angular resolution↗
Measurements of K-edge and L-edge extended x-ray absorption fine structure at the national ignition facility (invited)
High-energy-density laser facilities and advances in dynamic compression techniques have expanded access to material states in the Terapascal regime relevant to inertial confinement fusion, planetary science, and geophysics. However, experimentally determining the material temperature in these extreme conditions has remained a difficult challenge. Extended X-ray Absorption Fine Structure (EXAFS), referring to the modulations in x-ray absorption above an absorption edge from photoelectrons’ interactions with neighboring atoms, has proven to be a versatile and robust technique for probing material temperature and density for mid-to-high Z elements under dynamic compression. The current platform at the National Ignition Facility has developed six configurations for EXAFS measurements between 7 and 18 keV for different absorption edges (Fe K, Co K, Cu K, Ta L3, Pb L3, and Zr K) using a curved-crystal spectrometer and a bright, continuum foil x-ray source. Here, in this work, we describe the platform geometry, x-ray source performance, spectrometer resolution and throughput, design considerations, and data in ambient and dynamic-compression conditions.
36 MATERIALS SCIENCE↗
Lifetimes and fine structure of the metastable autoionizing /1s2s2p/ /4/ P sub J states of the negative helium ion
Lifetimes and fine structure of differentially metastable autoionizing states of negative He ion in axial magnetic field, using time of flight techniques
Blau, L. M.↗
Accuracy of mapping the Earth's gravity field fine structure with a spaceborne gravity gradiometer mission
The spaceborne gravity gradiometer is a potential sensor for mapping the fine structure of the Earth's gravity field. Error analyses were performed to investigate the accuracy of the determination of the Earth's gravity field from a gravity field satellite mission. The orbital height of the spacecraft is the dominating parameter as far as gravity field resolution and accuracies are concerned.
Kahn, W. D.↗
Fine Structure of Magnetospheric Magnetosonic Waves: 1. Elementary Rising‐Tone Emissions Within Individual Harmonic
Abstract The present study uncovers the fine structures of magnetosonic waves by investigating the EFW waveforms measured by Van Allen Probes. We show that each harmonic of the magnetosonic wave may consist of a series of elementary rising‐tone emissions, implying a nonlinear mechanism for the wave generation. By investigating an elementary rising‐tone magnetosonic wave that spans a wide frequency range, we show that the frequency sweep rate is likely proportional to the wave frequency. We studied compound rising‐tone magnetosonic waves, and found that they typically consist of multiple harmonics in the source region, and may gradually become continuous in frequency as they propagate away from source. Both elementary and compound rising‐tone magnetosonic waves last for ∼1 min which is close to the bounce period of the ring proton distribution, but their relation is not fully understood.
Li, Jinxing↗