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The relation between the units and the readings of time and space coordinates of the terrestrial and the barycentric frames is discussed from the viewpoint of general relativity. Attention is paid to the unit of space coordinates since the International Astronomical Union (IAU) regulates only the unit of time coordinate in the above two frames. Two definitions on unit of length are examined and their effects on the numerical expression of coordinate transformation, equations of planetary motions, and those for light propagation time are discussed. A clear conflict is found between the IAU(1976) recommendation on the definition of the time-scales in different frames and the statement that all constants in the IAU(1976) new system of astronomical constants are defined in terms of the international system of units (SI units). In order to dissolve this conflict, one of the two examined definitions on unit of length is proposed to be adopted, which requests the least alteration on the current procedures to analyze the astrometric observations such as radar/laser rangings, range and range-rate measurements, and very long baseline interferometric observations. An interpretation of numerical values in the IAU(1976) system of astronomical constants is also presented. It is stressed that the definition proposed in this paper requires that a slightly different formula from the current one be used in the numerical transformation of coordinates between the terrestrial and the barycentric frames.
The treatment of the coordinate systems is briefly reviewed in the Newtonian mechanics, in the special theory of relativity, and in the general relativistic theory, respectively. Some reference frames and coordinate systems proposed within the general relativistic framework are introduced. With use of the ideas on which these coordinate systems are based, the proper reference frame comoving with a system of mass-points is defined as a general relativistic extension of the relative coordinate system in the Newtonian mechanics. The coordinate transformation connecting this and the background coordinate systems is presented explicitly in the post-Newtonian formalism. The conversion formulas of some physical quantities caused by this coordirate transformation are discussed. The concept of the rotating coordinate system is reexamined within the relativistic framework. A modification of the introduced proper reference frame is proposed as the basic coordinate system in the astrometry. The relation between the solar system barycentric coordinate system and the terrestrial coordinate system is given explicitly.
Coronal images were taken in the light of the He I 10830 Å line, the 10000 Å continuum, and the Fe XIV 5303 Å line, with the aim of studying the thermal structure of the corona. In addition, spectroscopic observations were made in the violet wavelength region (3760-4060 Å) and near-infrared (10745-10835 Å), to obtain details of physical conditions of the corona, especially of its cool part. The data obtained do not show any distinct cool structures other than ordinary prominences. Some preliminary results concerning the corona and prominence structures are given.
Research in Celestial Mechanics, for the past three years, has mainly focused on the understanding of Chaos on all its aspects. The always larger number of potential applications (meteors, KBO, NEA, asteroids of the main belt but also exoplanets or galactic motions) and the development of new efficient tools, like the symplectic integrators, have allowed the passage from QUALITATIVE models (for example the transfer mechanisms) to real QUANTITATIVE results (like the calculation of lifetimes). This important step has contributed to (re)create collaborations between theoreticians and observers (for example, in the prediction of catastrophic impacts) and to situate the Celestial Mechanics in a wider scientific context.
Long term integrations of highly eccentric orbits are necessary to study the orbital evolution of comets and some minor planets. We discovered that the KS regularization is effective not only in the sense the magnitude of local error is reduced in the close approach but in the sense it dramatically reduces the positional error growth. In fact, it is in proportion to the fictitious time s while the Cowell method, the usual integration in 3-dimensional space leads to the positional error growing as a quadratic function of time. This good property is independent of the type of the integrators, of the type of the perturbations or of the magnitude of the nominal eccentricity. This phenomenon is based on the fact that the equations of motion in the KS variables are those of perturbed harmonic oscillators. As the best numerical integrator, we recommend the predictor formula of symmetric linear multistep method because (1) it runs fast since only one functional evaluation is required at each step, (2) its error constants are close to the minimum among the class of linear multistep methods, (3) its numerical error of the conserved quantities remains almost constant with time, and (4) it shows no stepsize resonance/instability in integrating the KS regularized equation of motions and the harmonic oscillator potential is the only case where the step size instability does not appear. Therefore the KS regularization is useful to investigate the long term behavior of perturbed two body problems for studying comets, minor planets, Moon, and artificial satellites.
The objective of this study was to examine temporal and regional variations of sporadic Creutzfeldt–Jakob disease (sCJD) in a retrospective study using Japanese national surveillance data from 2001 to 2010. We calculated the incidence of sCJD by age and sex, derived the standardized incidence in each of the 47 prefectures, and performed spatial disease clustering analysis. The average annual incidence of sCJD was 1·026 per million in men (637 patients) and 1·132 per million in women (733 patients), a significant sex difference after adjustment for age (P = 0·001). The ratios of familial CJD to sCJD apparently increased between 2001–2005 and 2006–2010, possibly as a result of the nationwide introduction of genetic testing after 2006. Based on the data of 2006–2010, certain geographical clusters of sCJD were identified. The incidence of sCJD was higher in several specific prefectures compared to the national average. Thus, sCJD appears to have regional variations, suggesting the existence of genetic or region-specific factors affecting the incidence of the disease.
The Commission 4 Organizing Committee began its work for the 2009-2012 triennium by revising the commission's terms of reference, which serve as our “mission statement.” The new terms of reference are:
(a)Maintain cooperation and collaboration between the national offices providing ephemerides, prediction of phenomena, astronomical reference data, and navigational almanacs.
(b)Encourage agreement on the bases (reference systems, time scales, models, and constants) of astronomical ephemerides and reference data in the various countries. Promote improvements to the usability and accuracy of astronomical ephemerides, and provide information comparing computational methods, models, and results to ensure the accuracy of data provided.
(c)Maintain databases, available on the Internet to the national ephemeris offices and qualified researchers, containing observations of all types on which the ephemerides are based. Promote the continued importance of observations needed to improve the ephemerides, and encourage prompt availability of these observations, especially those from space missions, to the science community.
(d)Encourage the development of software and web sites that provide astronomical ephemerides, prediction of phenomena, and astronomical reference data to the scientific community and public.
Promote the development of explanatory material that fosters better understanding of the use and bases of ephemerides and related data.
The heteroepitaxy of InP on Si substrates was investigated using MOCVD. A thin GaAs intermediate layer was used to alleviate the 8.4% lattice mismatch between InP and Si. With the use of this intermediate layer, four inch size, single domain InP epilayer with small residual stress was reproducibly grown on off-(100) oriented Si substrates. The etch pit density (EPD) of as-grown InP layer was 5x107~1x108 cm-2 . The post growth annealing of this epilayer at 800~850ºC in aPH3+H2 ambient reduced EPD to 1~2x107 cm-2
Pseudoelastic behavior of Fe3Ga single crystals regardless of a thermoelastic martensitic transformation was investigated focusing on the dislocation structure and the phase constituent. Large pseudoelasticity of 5 % recoverable strain appeared in Fe3Ga single crystals sufficiently annealed in the D03 single-phase region. In the crystals, uncoupled and paired 1/4 superpartial dislocations moved dragging the nearest-neighbor (NN) and next-nearest neighbor (NNN) anti-phase boundaries (APBs) during loading, respectively. During unloading, these APBs pulled back the superpartials resulting in large pseudoelasticity, which is similar to D03-ordered Fe3Al crystals. The dislocation configuration was closely related to the ordered domain structure developed in the D03 phase. Moreover, the precipitation of the thermally stable L12 phase was so slow that the metastable D03 phase developed even if the crystals were annealed in the (a+ L12) and (D03+ L12) phase fields in Fe-Ga equilibrium phase diagram. The metastable D03 phase also demonstrated large pseudoelasticity of which recovery ratio was above 80 %. On the other hand, if the L12 phase precipitated by long time annealing in the (a+ L12) region, the reversible motion of 1/4 superpartials was suppressed by the L12 phase resulting in a decrease in recovery ratio. In addition, the crystals aged in the (a+ D03) phase region showed small strain recovery.
Carbon in LEC GaAs was found to be introduced as CO from the ambient atmosphere; the oxygen concentration in the crystals decreased with increase in the duration of melting. An equilibrium segregation coefficient of oxygen in GaAs crystals was found by charged particle activation analysis to be 0.1, the value of which was smaller by a factor of 3~4 than that reported before.
We synthesized the highly ordered mesoporous thin films with alkyltrimethyl-ammonium (CnTMA+). The arrangement of mesopores was depend on the Si/surfactant ratio. The hexagonal(P6mm) arrangement was observed, when Surfactant/Si ratio was 1/10. Increasing the Surfactant/Si ratio to 1.6/10, the cubic (Pm3n) arrangements were observed. A steel vessel for the measurement of the nitrogen adsorption isotherms of thin film on the substrate was designed. It was found that mesopore arrangements in the film is more regular than that in the powder samples prepared by the same acidic synthesis conditions.
A new butt joining method for ceramics by microwave heating was developed. Ceramics were heated in a rectangular cavity. A klystron of maximum 3 kW at 6 GHz was used as the power amplifier. The heating system can control the iris, plunger and microwave power to keep a power efficiency up to 90% and a accuracy within ±10°C at 1800°C. Microwave ceramic-ceramic joining was tried by using this system. A bending strength of the joined alumina rod (92% purity) was 420 MPa without adhesive. This value was equal to the original strength. Silicon nitride ceramics were joined with adhesive, which was a sintered ceramic sheet having lower purity and larger dielectric loss factor than the base ceramics. The microwave energy was concentrated on the sheet, so that only the joining area was heated. The strengths of joined specimens were in excess of 70% of original strengths. The joined boundary line was not detected in microscopic observation, and there was little difference in microstructure between before and after joining. These results suggest that sintering aids in grain boundary phases were preferentially heated and melted or diffused, resulting in sound joining of ceramics.
We have carried out systematic experiments to explore the range of applicability of the two direct methods which are available for the determination of the nature of small clusters. Experiments in heavy-ion irradiated silver and copper, including direct comparisons with the results of Black-White contrast analysis (B-W), forced us to the conclusion that use of the 21/2D technique for the analysis of faulted loops is effectively impossible because of reciprocal-lattice spike and other effects. We used B-W analysis to investigate the nature of the clusters produced by room-temperature heavy-ion irradiation of copper. In-situ irradiations were performed in the Argonne HVEM-Tandem Facility using 40keV and 80keV Kr+ ions. Nearly all of the analysable first-layer loops were found to be vacancy in nature. Some deeper clusters were also certainly vacancy. There is no unequivocal evidence for interstitial loops under these conditions. The near impossibility of establishing that interstitial loops are not present is shown by the fact that a large fraction of loops - over 50% - could not be analysed either because they did not display clear B-W contrast under any condition or sufficiently consistent B-W contrast under several different operating conditions.
A low-temperature in situ ion-irradiation and annealing experiment has been performed by TEM in copper. Most defect clusters which persisted through an anneal to 120 K showed no size changes within the resolution (0.5 nm) of a new weak-beam sizing technique. Of 55 defects measured under a range of weakly diffracting conditions, 7 showed measurable size decreases while 3 showed size increases. We argue that these clusters are likely to be of vacancy and interstitial nature, respectively. Also on annealing to 120 K a fraction of about 25% of the clusters formed by irradiation with 600 kV Cu+ ions at 20 K disappeared, while a similar number of clusters appeared in different locations.
We discuss origin of ferromagnetism in dilute magnetic semiconductors (DMS) and propose accurate calculation method for Curie temperature from first-principles. For more realistic materials design, we simulate inhomogeneous impurity distribution due to the spinodal decomposition in DMS from first-principles. Combining these techniques, we discuss super-paramagnetism and blocking phenomena in DMS and propose fabrication method of DMS with high blocking temperature.
Gold nanorods, rod-shaped gold nanoparticles, have transverse and longitudinal surface plasmon (SP) bands at visible and near-infrared (IR) regions, respectively. Since the absorbed light energy is converted into heat, photothermal effect of gold nanorods can be triggered without damaging the tissues in the path of near-IR laser light. In this study, we tried to construct controlled release system of functional molecules from surface of gold nanorods mediated by the photothermal effect. First, we evaluated controlled release of poly(ethyleneglycol) (PEG) chains from PEG-modified gold nanorods (PEG-NR). Next, we employed double stranded oligonucleotide as a thermo-responsive dissociating group (DNA-NR). Finally, we evaluated photothermal release of PEG chains mediated retro-Diels-Alder reaction (PEG-DA-NR). For construction of controlled release system of functional molecules, these studies will provide important information about the photothermal reactions of surface molecules on the gold nanorods triggered by near-IR light irradiation.
Dr. George Kaplan, the current Vice-President of the Commission was nominated to be the new President. Dr. Catherine Hohenkerk was elected to be the next Vice-President of the Commission. As for the Membership of the Organizing Committee, Dr. Vondrak stepped down and Drs William Folkner of JPL and Steve Bell of HMNAO have been added. In the below, we present summaries of the reports from various institutions presented at the business session.
There were four 1.5-hour sessions of Division I business meetings during the XXVIIth IAU General Assembly. The first three were devoted to the reports of Commissions, Working Groups and services associated with the Division, discussion about plans for the next triennium and future structure of the Division. Scientific presentations on the future space astrometric mission Gaia were made at the fourth session.