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In this paper, a colloidal solution of copper nanoparticles was prepared from a Cu ion aqueous solution with the protein casein surfactant by a liquid phase reduction method at low temperature below 373K. For the casein concentration ranging from 6g/L to 75g/L, the formation of copper nanoparticle colloid were observed. As a result, the peak was observed at the ranging of 450 to 650 nm corresponding to the copper nanoparticle colloid plasmon absorption. As the surfactant concentration increases, the absorption spectrum tends to blue-shift and the particle diameter decreases. Thus, it indicated that the optical property and particle diameter of copper nanoparticle colloidal solution will be controlled by the protein casein surfactant concentration.
Type I storms are the most frequently observed solar phenomena at metre and decimetre wavelengths. Since the first identification of the emission of this type with a large sunspot group a great many type I storms have been recorded with radio-spectrographs, polarimeters and interferometers (see, for example, Wild, Smerd and Weiss, Kundu, Wild). Nevertheless, we can offer no satisfactory answers to the most fundamental questions about type I storms: ‘What kind of disturbances supply energy to a localized coronal region to maintain the storm activity for up to several days?’; ‘What is the emission mechanism responsible for the peculiar features observed in type I storms?’.
This paper describes the influence of microstructure, or more specifically grain orientation and grain size, on the in-line monitoring of copper interconnect properties during (self)-anneal using surface acoustic wave spectroscopy (SAWS). In electroplated Cu after (self)-anneal the SAWS frequency is lower for samples annealed at higher temperature because of the lower porosity induced elasticity. In sputtered Cu, the SAWS frequency shows a clear correlation with grain size, which is induced by a strong re-orientation of the copper film from the as-deposited (111) texture (E=190 GPa) to a strongly (100) textured super grain structure (E=78GPa).
We report an on-going blank-field multi-wavelength deep and wide survey of the Subaru/XMM-Newton Deep Survey Field (SXDF). The SXDF has been the focus of a wide range of multi-wavelength observing programs spanning the X-ray to the radio. These observations cover a large enough area (the initial optical imaging covers $\sim$1.3 deg$^{2}$) and depth ($B=28.2$) that they are not affected by large-scale structures (which exist on tens of Mpc scales) and allow us to study the distribution and evolution of high-$z$ galaxies and AGNs, and thus constrain theories for their formation. Our early results include: i) an indication of the primeval Large Scale Structure (LSS) at z $\sim$ 5.7, ii) an indication for the down-sizing of galaxy formation at z $\sim$ 1, iii) identifications of passively evolving systems, and evidence for early formation and the passive evolution of present-day early-type galaxies, and iv) discovery of a large number of optically obscured QSOs. As for the next step forward - we express our hope to use the next generation optical/IR Extremely Large Telescopes (ELTs) to obtain larger and deeper spectroscopy samples of the high-$z$ objects.
More than 4000 stars observed in both MOA and DENIS projects showing periodic or quasi-periodic light curves are studied. Almost all Mira stars are located on the classical period-luminosity relation, and the multiplicity of the period-luminosity relation is confirmed for small-amplitude stars. The colour-magnitude diagrams based on the MOA red band, Rm, and Ks constructed for the sequences, form a single strip with small successive shifts.
Adhesion strength in sputter-deposited Cu thin films on various types of barrier layers was investigated by scratch test. The barrier layers were Ta1-xNx with varied nitrogen concentration of 0, 0.2, 0.3, and 0.5. Microstructure observation by TEM indicated that each layer consists of mixed phases of β;-Ta, bcc-TaN0.1, hexagonal-TaN, and fcc-TaN, depending on the nitrogen concentration. A sulfur- containing amorphous phase was also present discontinuously at the Cu/barrier interfaces in all samples. Scratch test showed that delamination occurred at the Cu/barrier interface and that the overall adhesion strength increased with increasing the nitrogen concentration. A good correlation was found between the measured adhesion strength and the composing phases in the barrier layer.
We studied 147 long-period red variable stars in the Large Magellanic Cloud from the MOA database. Amongst them, seven red luminous stars are likely pulsating in a higher mode.
The work of Commission 25 covers a wide range of topics concerning the measurement of magnitude, colour and polarisation of astronomical objects. As such, the area of interest covers virtually every field of astrophysical research in the visual and infrared spectral domain. Our reports cover some aspects of photometry and polarimetry as a technique rather than being an account of research highlights over the last three years.
A review of the MOA (Microlensing Observations in Astrophysics) project is presented. MOA is a collaboration of approximately 30 astronomers from New Zealand and Japan established with the aim of finding and detecting microlensing events towards the Magellanic Clouds and the Galactic bulge, which may be indicative of either dark matter or of planetary companions. The observing program commenced in 1995, using very wide band blue and red filters and a nine-chip mosaic CCD camera.
As a by-product of these observations a large database of CCD photometry for 1.4 million stars towards both LMC and SMC has been established. In one preliminary analysis 576 bright variable stars were confirmed, nearly half of them being Cepheids. Another analysis has identified large numbers of blue variables, and 205 eclipsing binaries are included in this sample. In addition 351 red variables (AGB stars) have been found. Light curves have been obtained for all these stars. The observations are carried out on a 61-cm f/6.25 telescope at Mt John University Observatory where a new larger CCD camera was installed in 1998 July. From this latitude (44° S) the Magellanic Clouds can be monitored throughout the year.
The red variables whose amplitude is larger than 1.3 mag in the MOA database are studied for the LMC. Among 3 196 such stars, 532 stars are likely to be Miras or red semiregular variables. The period–colour relation of these stars is shown.
A large database of CCD photometry for 1.4 million stars towards both the LMC and the SMC, which has been established by the MOA project, is a useful resource to study variable stars. In our preliminary study, variables identified as β Lyrae type stars and Herbig Ae/Be stars have been found amongst blue stars.
The growth of the shells of C60 crystals was carried out under various conditions. The detailed structures of the grown shells were investigated by transmission electron microscopy and Raman spectroscopy. The shells were formed during thermal sublimation of the C60 crystals, which were irradiated with white light in air. The shells were mainly composed of a kind of amorphous carbon. From these results, it is suggested that the oxygen-induced disintegration of C60 cages is responsible for the shell formation.
A high time- and spatial-resolution radio interferometer for solar observations has been constructed at Nobeyama (Figure I.; Nakajima et al. 1994). The Nobeyama Radioheliograph consists of 84 antennas, 0.8m in diameter, arranged on a T-shape lines of 500m in the EW and 220m in the NS directions. The time resolution is 50 ms and the spatial resolution is 10”. The field of view is 40’ at the observing frequency 17GHz, which enables us to watch the whole sun. The radioheliograph has observed hundreds of flares during the few months since the beginning of regular observations in July ‘92, and such powerful performance has never before been demonstrated in the history of solar radio observations.
Most position sensitive proportional counters (PSPCs) currently used in X-ray diffraction experiments have a dead time longer than 5 μs. Though such PSPCs are useful in measuring weak diffraction diagrams, a faster counter is needed to detect strong X-ray diagrams produced with synchrotron radiation sources. The long dead time of PSPCs using a charge division position read-out is due to the slow analog division circuit plus analog-to-digital converter employed in the present system. A fast processor can be built utilising two high-speed ADCs to digitize voltage signals from the detector, followed by a digital divider to compute position of detected photons. The present paper describes the design of such a processor and some preliminary testings of its performances.
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