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Intrinsic γ-Copper (I) Chloride is an ionic I-VII compound semiconductor material with relatively low conductivity. To fabricate an efficient electroluminescent device based on CuCl nanocrystals (NC) the conductivity of the CuCl NC film should be relatively high. In order to improve the conductivity of CuCl films, nanocrystals were embedded in a highly conductive polymer (Polyaniline) and deposited on glass substrates via the spin-coating method. The deposited films were heated at 140°C for durations between 1 and 12 hours in vacuo. The room temperature UV-Vis absorption spectra for all CuCl films showed both Z1,2 and Z3 excitonic absorption features and the absorption intensity increased as the anneal time increased. Room temperature photoluminescence (PL) measurements of the hybrid films reveal very intense Z3 excitonic emission. Room temperature X-ray diffraction (XRD) confirmed the preferential growth of CuCl nanocrystals whose average size is ≈40 nm in the <111> orientation. Resistivity measurements were carried out using a four-point probe system, which confirmed that the resistivity of the composite film was ≈500 Ω/cm. This is an improvement when compared to the vacuum evaporated CuCl thin films.
Research indicates that people suffering from obsessive compulsive disorder (OCD) possess several cognitive biases, including a tendency to over-estimate threat and avoid risk. Studies have suggested that people with OCD not only over-estimate the severity of negative events, but also under-estimate their ability to cope with such occurrences. What is less clear is if they also miscalculate the extent to which they will be emotionally impacted by a given experience.
The aim of the current study was twofold. First, we examined if people with OCD are especially poor at predicting their emotional responses to future events (i.e. affective forecasting). Second, we analysed the relationship between affective forecasting accuracy and risk assessment across a broad domain of behaviours.
Forty-one OCD, 42 non-anxious, and 40 socially anxious subjects completed an affective forecasting task and a self-report measure of risk-taking.
Findings revealed that affective forecasting accuracy did not differ among the groups. In addition, there was little evidence that affective forecasting errors are related to how people assess risk in a variety of situations.
The results of our study suggest that affective forecasting is unlikely to contribute to the phenomenology of OCD or social anxiety disorder. However, that people over-estimate the hedonic impact of negative events might have interesting implications for the treatment of OCD and other disorders treated with exposure therapy.
Borsboom et al. have written a trenchant critique of biological reductionism in psychopathology. After commenting on recent controversies concerning the network perspective, I discuss ways of integrating biology into the network enterprise.
Obsessive–compulsive disorder (OCD) is often co-morbid with depression. Using the methods of network analysis, we computed two networks that disclose the potentially causal relationships among symptoms of these two disorders in 408 adult patients with primary OCD and co-morbid depression symptoms.
We examined the relationship between the symptoms constituting these syndromes by computing a (regularized) partial correlation network via the graphical LASSO procedure, and a directed acyclic graph (DAG) via a Bayesian hill-climbing algorithm.
The results suggest that the degree of interference and distress associated with obsessions, and the degree of interference associated with compulsions, are the chief drivers of co-morbidity. Moreover, activation of the depression cluster appears to occur solely through distress associated with obsessions activating sadness – a key symptom that ‘bridges’ the two syndromic clusters in the DAG.
Bayesian analysis can expand the repertoire of network analytic approaches to psychopathology. We discuss clinical implications and limitations of our findings.
The program has been continued thanks to the financial help of IAU, Unesco, and of local authorities. A school has been held in Lembang, Indonesia from May 16 to June 2, 1983, with students from India, Indonesia, Malaysia, Philippines, and Thailand. The Local Organizing Committee, chaired by B. Hidayat was very efficient, and the school is considered to be one of the most successful held to date. Both teachers and students expressed their appreciation to the School Secretary, Dr J. Kleczek, and to the IAU Executive Committee. Another school, foreseen in Venezuela for September 1983, had to be cancelled due to the lack of support of the Venezuelan Research Council. There are plans to hold several schools during the 1985-1988 period.
Since the date of the 1935 Paris meeting two total eclipses have been successfully observed. Throughout the long path crossing Siberia and Japan the weather on June 19, 1936 on the whole about lived up to predictions. On account of widely scattered clouds neighbouring expeditions had quite different luck with the weather. In contrast, the June 8, 1937 eclipse was seen throughout the whole track under universally clear skies, which is all the more surprising for the reason that eclipse expeditions to the tropics usually fare badly with the weather. Stewart and Stokley in a ship at sea were able to observe the eclipse with a measured duration of 7 min. 6 sec., the longest period of totality in 1200 years.
(i) 1936, June 19. The Eclipse Committees of Japan and the U.S.S.R. have been making preliminary meteorological studies of the weather conditions along the belt of totality in their respective countries. The Japanese Committee report (Bulldin, Kwasan Observatory, 283, 1934) that, while at the extreme east and west of their totality zone the weather prospects are unfavourable, for the central part, along the north-east coast of the island of Hokkaido, from Esasi to Monpetu and in a region round Syari the weather conditions are as good as in the best seasons of Tokyo and Kyoto in an ordinary year. A pamphlet giving all information is being prepared and will shortly be circulated in astronomical circles, but it may be mentioned that Monpetu and Syari are accessible by rail from the port of Otaru. There is electric current, 100 V, A.c., labour is readily available and accommodation will be possible for small parties.
The Working Group often overlaps in responsibilities with other Commissions, particularly with Commission 46. Some projects (e.g. TAD) may begin on the initiative of our Group but are maintained by Commission 46. TAD programmes are now running in Viet Nam and Central America and one will begin soon in Morocco. Preliminary inquiries have been received from other countries.
Commission 46 is dedicated to Teaching of Astronomy. Commission 46 can be seen as an
extension of the IAU Executive Committee in the sense that each adhering country has
appointed a national representative to the Commission. National Representatives maintain
liaison between the Commission and the home country, and write national triennial reports
on development of astronomy on their nations. Other IAU astronomers, with special interest in education, can become regular individual members of the Commission. Non-IAU
members can be invited by the Commission to serve for one triennial term. Commission
46 considers that one of its major duties is to contribute to enhance astronomy education
in developing countries. The Newsletter, the International School for Young Astronomers,
the Visiting Lecturer Program and the Travelling Telescope are examples of such activities administered by the Commission. The strength of Commission 46 comes from the hard
work that its members do in order to promote astronomy education worldwide.
The chief activities of the Commission for this period were the organizing of two important meetings. The first was held as Joint Discussion 5 at the Kyoto General Assembly in August 1997. The proceedings have now appeared as “Preserving the Astronomical Windows”, edited by S. Isobe (1997).
Digital stacking of Schmidt Plates greatly increases the depth of the data allowing detection of galaxies at ∼ 1. We can probe the angular correlations of galaxy and cluster positions over scales of ∼ 500h−1 Mpc. Radial distance information can be obtained by identifying radio galaxies in the field and using their “standard candle” properties. A search for cosmic string effects, beginning with the stacked dataset, has now been extended to ∼ 100 equatorial J-plates.
We describe the cases of two children who both presented in infancy with recurrent severe pulmonary hypertensive crises. Exhaustive clinical work-up failed to identify an underlying aetiology. The patients had no clinical response to steroids, immunoglobulins, or pulmonary vasodilators. Post-mortem examination revealed extensive invasive pulmonary capillary haemangiomatosis. There was no evidence of pulmonary venous occlusive disease. Given the lethal nature of this condition, early consideration of referral to a lung transplant centre should be considered in selected patients.
The apparatus for X-ray diffraction imaging (XRDI) of 450-mm wafers, is now placed at the ANKA synchrotron radiation source in Karlsruhe, is described in the context of the drive to inspect wafers for plastic deformation or mechanical damage. It is shown that full wafer maps at high resolution can be expected to take a few hours to record. However, we show from experiments on 200-, 300-, and 450-mm wafers that a perimeter-scan on a 450-mm wafer, to pick up edge damage and edge-originated slip sources, can be achieved in just over 10 min. Experiments at the Diamond Light Source, on wafers still in their cassettes, suggest that clean-room conditions may not be necessary for such characterization. We conclude that scaling up of the 300-mm format Jordan Valley tools, together with the existing facility at ANKA, provides satisfactory capability for future XRDI analysis of 450-mm wafers.
Solder based flip-chip packaging has prompted interest in many integrated circuit (IC)packaging applications due to its many advantages in terms of cost, package size, electricalperformance, input/output density, etc. The ball grid array (BGA) is one of the most commonflip-chip packaging techniques used for microprocessor applications. However, mechanicalstresses induced by the flip-chip process can impact adversely on the reliability of production.
White beam synchrotron x-ray topography (SXRT), a non-destructive technique, has beenemployed to investigate the spatial extent of strain fields imposed on the underlying siliconsubstrate for Intelν®Pentiumν®III microprocessors due to the lead-tin solder bump process for BGApackaging. Large area and section back-reflection SXRT images were taken before and after asimulation of the reflow process at 350°C in atmosphere. The presence of induced strain fields inthe Si substrate due to the overlying bump structures has been observed via the extinction contrasteffect in these x-ray topographs. In addition, orientational contrast effects have also been foundafter the reflow process due to the severe stresses in the underlying silicon beneath the lead bumps.The estimated magnitudes of stress, ∣σ∣, imposed on the underlying silicon were calculated to be100 MPa. The spatial strains in the underlying silicon were relieved dramatically after the leadbumps were removed from the wafer, which confirms that the bumps are indeed a major source ofstrain in the underlying Si. Finite element analysis (FEA) has also been performed in 2-D planestrain mode. The magnitudes and spatial distribution of the stresses after the reflow process are ingood agreement with the SXRT results.
The Epitaxial Lateral Overgrowth (ELO) of GaN on Al2O3 using a SiO2 mask with different fill factors (ratio of stripe opening width to stripe period) is examined with White Beam Synchrotron X-ray Topography (WBSXT) and X-ray rocking curve analysis. The sapphire substrate was identified with a dislocation density of the order of ~106cm-2. WBSXT in both transmission and back reflection mode is used to image the ELO GaN and confirms that crystal planes in the lateral overgrown part (wing) are tilted, and that the wing tilt increases as the fill factor increases. X-ray rocking curve and WBSXT measurements confirm the same wing tilt tendency as the fill factor changes. The WBSXT method provides a measure of the maximum wing tilt, while the X-ray rocking curve method gives the average wing tilt. The average wing tilt reaches about 1602 arcsec at a fill factor of 0.625, but the maximum wing tilts can reach values as large as 2372 arcsec when the fill factor is only 0.571. This study shows that WBSXT is an effective method in dislocation and wing tilt determination for the GaN on Al2O3 ELO epilayer system or indeed for similar systems. The tilted wings induce a slightly lower compressive stress in the coalesced region of the GaN epilayer.
Understanding the effects of growth conditions on the process of self-organisation of Ge nanostructures on Si is a key requirement for their practical applications. In this study we investigate the effect of preconditioning with a high-temperature hydrogenation step on the nucleation and subsequent temporal evolution of Ge self-assembled islands on Si (001). Two sets of structures, with and without H2 preconditioning, were grown by low pressure chemical vapour deposition (LPCVD) at 650°C. Their structural and compositional evolution was characterised by Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM) and micro-Raman (νRaman) spectroscopy. In the absence of preconditioning, we observe the known evolution of self-assembled Ge nanostructures on Si (001), from small islands with a narrow size distribution, to a bimodal size distribution, through to large islands. Surface coverage and island size increase steadily as a function of deposition time. On the H2 preconditioned surface, however, both nucleation rates and surface coverage are greatly increased during the early stages of self-assembly. After the first five seconds, the density of the islands is twice that on the unconditioned surface, and the mean island size is also larger, but the subsequent evolution is much slower than in the case of the unconditioned surface. This retardation correlates with a relatively high measured stress within the islands. Our results demonstrate that standard processes used during growth, like H2 preconditioning, can yield dramatic changes in the uniformity and distribution of Ge nanostructures self-assembled on Si.
In this research, Atomic Force Microscopy (AFM) is used to investigate living neurons. Three-dimensional images of developing and dying neurons have been obtained, providing neuroscientists their first views of these dynamic structures. The unparalleled resolution provided by AFM reveals dorsal root ganglion (DRG) cells to be more complex and variable than anticipated. AFM is also used to physically contact or manipulate the cell, and thus perturb its development, and/or to measure important physiologically parameters such as surface pressure. Neural cell damage is induced by the AFM tip, which is subsequently used to image the cell's morphological response. A 3-D view of the neural cell collapse, due to this insult, suggests alternative ideas concerning acute neuronal (cellular) sealing and repair. Repair of the injured neuron using electric fields and biomolecules is also investigated, supporting clinical trials for paralysis research. AFM force measurements are used to monitor cellular activity and membrane interactions during various stages of the neural cell life cycle. The full versatility of AFM will be applied to further the understanding of neurogenesis and neurotrauma.