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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.
The large-amplitude δ Scuti star CY Aqr was observed from sites in the U.S.A., South Africa and Australia during August 1988. Coates et al. (1991) published 48 new times of maximum light derived from these observations and assembled, from the literature, previous times of maximum light. It is clear that the period of the star is changing with the balance of evidence favouring discrete changes in 1951 and 1966, rather than a continuous change.
It has been suggested by Fitch (1973) and Else (1972), from an analysis of the observations of Zissell (1968), that there is a secondary frequency present in CY Aqr. Coates et al. (1992) have analysed both the 1988 observations and those of Zissell. After subtracting the primary frequency and its harmonics, they find no stable secondary frequency above the noise level of two millimagnitudes.
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.
We report on the status of the CCD cameras for the Kiso 105-cm Schmidt telescope. We have two types of cameras – single-chip and mosaic. The single-chip camera is available for common use. At present about 90 % of the telescope time is allocated to observations with CCD cameras.
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.
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.
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.
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.
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.
A systematic near-infrared survey was made for globular clusters in the Magellanic Clouds. Two infrared stars were discovered in NGC419 (SMC) and NGC1783 (LMC). NGC419 and NGC1783 are well-studied rich globular clusters whose turn-off masses and ages are estimated MTO ~ 2.0 Mʘ and т ~1.2 Gyr for NGC419, and MT0 ~ 2.0 Mʘ and т ʘ 0.9 Gyr for NGC1783, respectively.
The periods of the infrared light variations were determined to be 540 dfor NGC419IR1 and to be 480 d for NGC1783IR1, respectively. Comparison of the measurements with the period—if magnitude relation for carbon Miras in the LMC by Groenewegen and Whitelock(1996) revealed that the Kmagnitudes of the infrared stars were fainter by about 0.3 — 0.8 magnitude than those predicted by the P — K relation. This deviation can be explained if the infrared stars are surrounded by thick dust shells and are obscured even in the K band. The positions of NGC419IR1and NGC1783IR1 on the P — K diagram suggest that AGB stars with the main sequence masses of about 2 Mʘ start their heavy mass-loss when P ʘ 500 d.
In this work a new generation of periodic mesoporous organosilica (PMO) low-k dielectrics with targeted k-values 2.0 and 1.8 is evaluated. In addition, impact of two different curing processes on properties of the mesoporous material is analyzed. It is shown that removal of templating organics with thermal annealing leads to formation of mechanically robust and chemically very stable material, while application of UV-assisted curing with broadband lamp (λ > 200 nm) causes pronounced decrease of film ability to sustain in diluted HF solution. The explanation of that phenomenon is given in terms of silica-ring structures formed within organosilica skeleton.
Adipose tissue (AT) dysfunction links obesity of any cause with cardiometabolic disease, but whether early-life nutritional deficiency can program adipocyte dysfunction independently of obesity is untested. In 3–5-month-old juvenile microswine offspring exposed to isocaloric perinatal maternal protein restriction (MPR) and exhibiting accelerated prepubertal fat accrual without obesity, we assessed markers of acquired obesity: adiponectin and tumor necrosis factor (TNF)-α messenger ribonucleic acid (mRNA) levels and adipocyte size in intra-abdominal (ABD-AT) and subcutaneous (SC-AT) adipose tissues. Plasma cortisol, leptin and insulin levels were measured in fetal, neonatal and juvenile offspring. In juvenile low-protein offspring (LPO), adipocyte size in ABD-AT was reduced 22% (P = 0.011 v. controls), whereas adipocyte size in SC-AT was increased in female LPO (P = 0.05) and normal in male LPO; yet, adiponectin mRNA in LPO was low in both sexes and in both depots (P < 0.001). Plasma leptin (P = 0.004) and cortisol (P < 0.05) were reduced only in neonatal LPO during MPR. In juveniles, correlations between % body fat and adiponectin mRNA, TNF-α mRNA or plasma leptin were significant in normal-protein offspring (NPO) but absent in LPO. Plasma glucose in juvenile LPO was increased in males but decreased in females (interaction, P = 0.023); plasma insulin levels and insulin sensitivity were unaffected. Findings support nutritional programming of adipocyte size and gene expression and subtly altered glucose homeostasis. Reduced adiponectin mRNA and adipokine dysregulation in juvenile LPO following accelerated growth occurred independently of obesity, adipocyte hypertrophy or inflammatory markers; thus, perinatal MPR and/or growth acceleration can alter adipocyte structure and disturb adipokine homeostasis in metabolically adverse patterns predictive of enhanced disease risk.
Poor fetal growth and associated prepubertal growth acceleration are linked to increased risk of cardiometabolic dysfunction in later life, but whether obesity is integral to ‘catch-up’ growth and its ensuing risks are unknown. In microswine offspring exposed to perinatal maternal protein restriction (MPR), we measured body and organ sizes (during MPR); linear growth and weight gain (birth to 5 months of age); feed intake and utilization efficiency (5–14 weeks); and body composition at 6 and 11 weeks of age (by dual-energy X-ray absorptiometry, DEXA). During MPR, low protein offspring (LPO) showed asymmetric growth restriction with reduced body weight (Wt):length (Lth) at birth and elevated heart Wt:liver Wt ratio by 2 weeks of age. In LPO, after slow early postnatal growth (0–5 weeks), subsequent linear growth on ad libitum normal feed was absolutely accelerated (cm/week; P < 0.001) over 6–11 weeks but normal thereafter, whereas absolute weight gain (kg/week) was similar to controls but accelerated relative to lower LPO nadir weights. Concurrently, rates of fat and lean tissue accrual in LPO over 6–11 weeks were similar to normal protein offspring in absolute terms (g/5 weeks) but increased relative to lower mass at 6 weeks, yielding normal lean:Lth but reduced fat:Lth ratios at 11 weeks. LPO had higher relative feed intake (g/kg/meal) in both sexes and higher feed efficiency in females over 5–11 weeks of age. Findings suggest that postnatal linear growth acceleration preserved thinness in juvenile LPO. Given separately reported abnormalities of vascular (Bagby et al., 2011) and adipocyte function in juvenile LPO, (DuPriest et al., 2011) findings demonstrate that perinatal MPR programs catch-up growth and cardiovascular abnormalities independently of obesity.
In the article by Crabtree et al., published in Transactions IAU, Volume XXVIIIA there was an error in the list of authors. Pedro Russo was not included in the list of authors on the organizing committee. The editors apologise to Pedro Russo for this error. The correct authorship is published below:
PRESIDENT: Dennis R. Crabtree
VICE-PRESIDENT: Lars Lindberg Christensen
PAST PRESIDENT: Ian Robson
ORGANIZING COMMITTEE: Oscar Alvarez Pomare, Augusto Damineli Neto, Richard T. Fienberg, Anne Green, Ajit K. Kembhavi, Pedro Russo, Kazuhiro Sekiguchi, Patricia Ann Whitelock, Jin Zhu
Commission 55 was approved at the IAU General Assembly in Prague following the great success of the Communicating Astronomy Working Group, which had been set up in 2003. It resides within Division XII and the mission statement of the Working Group has been incorporated into the Commission:
•To encourage and enable a much larger fraction of the astronomical community to take an active role in explaining what we do (and why) to our fellow citizens.
•To act as an international, impartial coordinating entity that furthers the recognition of outreach and public communication on all levels in astronomy.
•To encourage international collaborations on outreach and public communication.
•To endorse standards, best practices and requirements for public communication.
Fe precipitation on bulk stacking faults in Czochralski-grown silicon are investigated by means of the electron-beam-induced-current (EBIC) technique and other techniques. It is found that Fe impurities only precipitate on Frank partial dislocations bounding stacking faults when the specimen is cooled slowly; however, they precipitate on both Frank partials and fault planes when the specimen is cooled fast. It is explained that small oxygen precipitates on fault planes, together with Frank partials, serve as the gettering centers for Fe impurities in the fast cooled specimen.
The large visible optical penetration depth makes it difficult to isolate the Raman signals of SiC epilayers from those of the substrates such as SiC, sapphire and Si when visible laser lines are used. In this work, confocal micro-Raman was used to characterize 3C, 4H and 6H SiC layers on different substrates with enhanced lateral resolution (˜ 0.8 μm) and depth resolution (˜ 2 μm). Both lateral and depth variation of the free electron concentration and scattering time were measured from n− SiC epi layers on n+ SiC substrates and from H+ implanted SiC. A defect mode induced by oxidation process was also analyzed as function of the depth and the lateral position.
A new Photoluminescence (PL) method has been developed to detect defects in the near surface region of Si wafers and Si-on-insulator (SOI) structures. Wafer maps (up to 300 min diameter) can be readily acquired and areas of interest can be scanned at high resolution (≈1 μm). The excitation laser beam is modulated to confine the photogenerated carriers; defects are observed due to the localised reduction of the carrier lifetime. Si p-type (10 Ohm.cm) wafers were intentionally contaminated with various levels of Ni and Fe (1×109−5×1010 atoms/cm2) and annealed. The PL intensity was observed to decrease due to the metal related non-radiative defects. Whereas in contrast, for Cu, (1×109−5×1010 atoms/cm2) the PL intensity actually increased initially and reached a maximum value at 5×109 atoms/cm2. It is suggested that during contamination the Cu related defects have complexed with existing defects (that have stronger recombination properties) and increased the PL. Further Cu contamination (1×1010−5×1010 atoms/cm2) produced a reduction in the PL intensity. PL mapping of strained SiGe epilayers showed that misfit dislocations can be detected and PL can be used to evaluate material quality.
PL maps of SOI bonded wafers revealed that the non-bonded areas, voids or gas bubbles could be detected. This was confirmed using defect etching and polishing, voids as small as ≈30 μm in diameter could be detected. SOI wafers fabricated using the separation by implanted oxygen (SIMOX) technique were also analysed, variations in the recombination properties of the layer could be observed. Further inspection using transmission electron microscopy (TEM) revealed that the defects were non-uniformities of the buried oxide covering several microns and containing tetrahedral stacking faults. Focused ion beam (FIB) milling and secondary ion mass spectrometry (SIMS) showed that these defects were at the Si/SiO2 interface and were chemically different to the surrounding area.