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A new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.
We report on the results of CCD photometric observations of the open cluster NGC 2539. Eight new variable stars have been found in the observed field of this cluster. However, no γ Doradus-type variability was found among the member stars.
A time-series CCD photometric survey of variable stars in open clusters has been in progress using 1.8-m telescope at the Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We present preliminary results of time series photometry for the intermediate-age open cluster NGC 2301.
Through time-series CCD photometry of the globular cluster M 53, we have discovered eight new SX Phoenicis type stars. All the new SX Phoenicis stars are located in the blue straggler star region in the color-magnitude diagram of M 53. In addition, we have obtained light curves for 45 known RR Lyrae stars.
Behavioral and psychological symptoms of dementia (BPSD) are often considered to be the greatest challenge in dementia care, leading to increased healthcare costs, caregiver burden, and placement into care facilities. With potential for pharmacological intervention to exacerbate behaviors or even lead to mortality, the development and rigorous testing of non-pharmacological interventions is vital. A pilot of the Tailored Activities Program (TAP) for reducing problem behaviors in people with dementia was conducted in the United States with promising results. This randomized trial will investigate the effectiveness of TAP for reducing the burden of BPSD on persons with dementia and family caregivers within an Australian population. This trial will also examine the cost-effectiveness and willingness to pay for TAP compared with a control group.
This randomized trial aims to recruit 180 participant dyads of a person with dementia and their caregivers. Participants will have a diagnosis of dementia, exhibit behaviors as scored by the Neuropsychiatric Inventory, and the caregiver must have at least 7 h per week contact. Participants will be randomly allocated to intervention (TAP) or control (phone-based education sessions) groups, both provided by a trained occupational therapist. Primary outcome measure will be the revised Neuropsychiatric Inventory – Clinician rating scale (NPI-C) to measure BPSD exhibited by the person with dementia.
This trial investigates the effectiveness and cost-effectiveness of TAP within an Australian population. Results will address a significant gap in the current Australian community-support base for people living with dementia and their caregivers.
Striking progress in the development of II-VI semiconductor heterostructures, coupled with seminal advances in doping, has very recently led to the first demonstration of blue and blue/green diode lasers operating from cryogenic to room temperature. The active region in these devices was based on the (Zn, Cd)Se/ZnSe multiple quantum wells (MQW) which had earlier been actively studied as a candidate for laser medium by optical pumping techniques. We report on the performance of such MQW diode lasers with emphasis on structural versatility in terms of preparation on both p-type and n-type GaAs substrates, and where sulfur is or is not incorporated for blue/green color lasing. In this work we have obtained pulsed, high power, high quantum efficiency laser emission up to near room temperature conditions. Efficient LED devices are described which operate in the blue (494nm) at room temperature.
We have obtained continuous-wave laser operation at room temperature from a (Zn,Mg)(S,Se)-based Il-VI separate-confinement heterostructure where injection of holes into the p-type quaternary was achieved through the employment of a Zn(Se,Te) graded-bandgap contact. The laser devices exhibit threshold current densities of below 300 A/cm2 and voltages below 6 V. Issues related to the control of the growth of the quaternary (Zn,Mg)(S,Se) compound, and a proposal to further reducing the laser operating voltage will also be described.
Tin oxide thin films were grown on Si(100) substrates by a hybrid ion beam consisting of a partially ionized beam and a cold hollow cathode ion source. Tin metal particles were ionized and accelerated by a partially ionized ion beam source while oxygen gas was introduced or ionized oxygen was introduced upon the Si substrate. When oxygen gas was blown near the substrate during Sn metal evaporation, the composition of deposited tin oxide films revealed mainly Sn metal and SnO, whereas tin dioxide films with highly preferred orientation of SnO2<200 or SnO2<110 axis were successfully grown when ionized oxygen was assisted. The calculated value of the composition ratio of oxygen to Sn(O/Sn) by AES for the SnO2(200) film was approximately 1.98. Moreover, the binding energy of Sn 3d5/2 was determined to be at 486.74 eV by XPS measurement, and the result coincided well with that of standard SnO2 powder. Compared with two different deposition processes, ionized oxygen assistance during tin metal evaporation would be considered to effectively improve oxygen content for the formation of tin dioxide thin films.
Vertically aligned carbon nanorods and multi walled carbon nanotubes (MWNTs) were synthesized by electron cyclotron resonance chemical vapor deposition (ECR-CVD) on Ni- coated glass substrates with the RF-self biasing of –100 and –200 V, respectively. High-resolution transmission electron microscopy indicated that the distance between adjacent graphene layers of carbon nanorods is much larger than that of well-graphitized MWNTs. In electron-energy-loss spectra, the energy of π+σ plasmon peak for the carbon nanorod shifts towards lower value of 23.8 eV, by comparison with the well-graphitized MWNT at 25.5 eV. In addition, the π palsmon peak at 6 eV is clearly defined for the well-graphitized MWNT, but not seen for the carbon nanorod. X-ray photoelectron spectroscopy also showed that the delocalization of π electrons gets more pronounced with the structural evolvement from the carbon nanorod to the well-graphitized MWNT. Therefore, it is suggested that ionic bombardment can provide sufficient internal energy for dehydrogenation from hydrocarbon molecules, and thus, well-graphitized MWNTs could be grown even at low temperatures.
As the size of integrated circuit is scaled down, the importance of Si wafer cleaning has been emphasized. Especially, in the ULSI level device, the cleaning has a great influence on device yields and reliabilities. In this study, we investigate the effects of UV/03 and SCI steps in the HF last cleaning procedures. The UV/O3 and SCI cleaning steps are known to remove the organic contaminants. However, the combination of UV/O3 cleaning step with HF wet chemical solution to remove the metallic impurities has not been studied extensively. We have applied the UV/O3 and SCI steps in the middle of the HF last cleaning procedures and have analyzed Si substrates with TXRF, AFM, I-V, etc. The cleaning splits we applied consist with 4 different types, split 1 (piranha + HF), split 2 (piranha + UV/O3 + HF), split 3 (piranha + SC1 + HF) and split 4 (piranha + UV/O3 + HF repeated 3 times). The contents of metallic impurities were measured with using TXRF and splits 2 and 4 showed low average values of metallic contents. The surface morphologies after each cleaning examined with AFM and the split 3 exhibited rough surface. The electric properties were measured after forming a MOS capacitor with oxide thickness of 250Å. The high leakage current and low breakdown voltage were observed at split 3.
Highly efficient, two-dimensional arrays of parallel-addressed InGaN blue microLEDs with individual element diameters of 8, 12 and 20μm have been fabricated. In order to overcome the difficulty of interconnecting multiple device elements with sufficient step-height coverage for contact metallisation, a novel scheme involving the etching of sloped-sidewalls has been developed. The devices have I-V characteristics similar to those of broad-area reference LEDs fabricated from the same wafer, and give superior (3mW) light output in the forward direction to the reference LEDs, despite much lower active area. The external efficiencies of the micro-LED arrays improve as the dimensions of the individual elements are scaled down. This is attributed to scattering at the etched sidewalls of in-plane propagating photons into the forward direction.
We report metalorganic chemical vapor deposition-grown double heterostructure and multiple quantum well InAsSb/InAsSbP laser diodes emitting at 3 to 4 μm and light emitting diodes up to 5 μm. Maximum output power up to 1 W (from two facets) with differential efficiency above 70 % up to 150 K was obtained from a MQW laser with stripe width of 100 μm and cavity length of 700 μm for emitting wavelength of 3.6 μm at 90 K. Maximum operating temperature up to 220 K with threshold current density of 40 A/cm2 at 78 K were achieved from the double-heterostructure lasers emitting at 3.2 μm. The far-field beam divergence as narrow as 24° was achieved with the use of higher energy gap barrier layers, i.e., lower effective refractive index, in MQW active region. We also discuss the effect of composition-fluctuation in the InAsSb active region on the gain and threshold current of the lasers.
The effects of nitrogen-radical treated amorphous silicon (a-Si) films on laser-crystallization behavior have been studied for the improvement of the grain-growth and the surface roughness. The radical treatments were performed by the rf (13.56 MHz) plasma-enhanced-chemical-vapor-deposition (PECVD) system with N2 gas before the laser-crystallization. The grain-size of the laser-crystallized polycrystalline silicon (poly-Si) film with 600 seconds of radical-treatment time was remarkably increased by the relaxation of solidification process caused by the possible evolution of solid phase SiNx compounds which shows the low thermal conductivity. The electrical conductivity at 30 °C was rather lager value of 3×10-5 Ω-1cm-1 than 1×10-5 Ω-1cm-1 of poly-Si without radical treatment, while the highly resistive SiNx compounds were formed. From the SEM images, the surface roughness was also improved by the selective etching of the 5%-water-diluted hydrofluoric (HF) acid on the grain boundaries which the SiNx compounds were well segregated into during the laser-crystallization.
A study of Si-doped and Mg-doped AlxGa1-xN up to × ∼ 50 % and the characteristics of ultraviolet (UV) light emitting diodes (LEDs) with emission wavelengths at 340 nm and 290 nm are reported. By using grading super-lattices (SLs) before n-type AlGaN growth, surface roughness is much improved. Resistivity of 2.9×10-2 Ωcm and free electron concentrations of 2.9×10 cm- are achieved for n-type Al0.45Ga0.55N. The viability of effective p-type doping is defined by a minimum concentration of Mg required to offset the background impurities and, more importantly, a maximum limit above which inversion domains and structural defects start to nucleate, accompanied by a rapid degradation of electrical transport. Resistivity of 10 Ωcm and free hole concentrations above 1017 cm−3 are achieved for AlxGa1-xN up to × ∼ 50 % within an optimum window of Mg incorporation. Output powers up to 1.5 mW from small area 340 nm LEDs (< 100 μm diameter) and 110 μW from 290 nm LEDs (100 μm diameter) directly off a planar chip have been achieved under DC condition. For large area encapsulated lamp (1×1 mm2 device area and 0.52 mm2 mesa area), output power of 79 mW from 340 nm LEDs and 8.5 mW from 290 nm LEDs are achieved under pulse mode (1kHz, 2% duty factor).
To define the clinical and audiological features of normal-hearing tinnitus patients with spontaneous otoacoustic emissions, and to evaluate the role of spontaneous otoacoustic emissions in tinnitus generation.
Materials and methods:
Thirty-two patients with spontaneous otoacoustic emissions were compared with 29 patients without spontaneous otoacoustic emissions, regarding clinical and audiological aspects.
The mean age of the study group subjects was significantly lower, and they experienced the kindling effect less frequently than the control group. The mean tinnitus handicap inventory score of the study group was considerably higher than that of the controls, although the difference was not statistically significant. The study group had significantly quieter tinnitus, and higher transient evoked and distortion product otoacoustic emission responses, compared with the control group.
Normal-hearing tinnitus patients with spontaneous otoacoustic emissions have different clinical and audiological characteristics, compared with those without spontaneous otoacoustic emissions. Appropriate evaluation and treatment should be considered at an early stage in these patients.
Our aim was to determine whether the index of left ventricular mass increases during the acute and subacute phase of Kawasaki disease, and to investigate any relationship between this index and clinical and echocardiographic variables. We performed, therefore, a retrospective study of 66 children with Kawasaki disease, having a mean age of 2.85 years, comparing the findings with those obtained from 57 normal controls, having a mean age of 2.99 years. The data from the patients used for comparison was obtained during the acute and subacute phase of the illness, as well as during the phase of convalescence. We performed correlation analysis of the findings during the acute and subacute phase, determining the relationship between the index of left ventricular mass and other variables. The index was higher (p = 0.0461), and the velocity of propagation of left ventricular early diastolic flow was lower (p < 0.0001), during the acute and subacute phase when compared to control values. The index then reduced (p = 0.0001) during the phase of convalescent when compared to the acute and subacute phase. Levels of albumin in the serum (p = 0.0193), peak E velocity (p = 0.0479), and velocity of propagation (p = 0.0360) were found to be related to the index of left ventricular mass. Significant relationships were found between the differences in this index and differences in body weight when findings during the acute and subacute phase were compared to those of the phase of convalescence. The index of left ventricular mass, therefore, is increased during the acute and subacute phase of Kawasaki disease, and is associated with altered diastolic indexes. This elevation may be due to generalized myocardial swelling from acute inflammation and increased vascular permeability. Measuring this index as a potential predictor of diastolic function should be added to studies of cardiac function during the acute and subacute phase of Kawasaki disease.
Local extension of thyroid carcinoma can result in massive invasion of the trachea, causing severe airway compromise. The pre- and peri-operative management of such airway compromise is difficult but critical. We report the use of extracorporeal oxygenation support as an alternative peri-operative airway management option in such a situation. This approach facilitated curative surgery in a patient with papillary thyroid carcinoma invading the trachea.
We present a case report regarding extracorporeal oxygenation support in a patient with locally advanced thyroid carcinoma.
The patient was a 68-year-old woman with aggressive thyroid papillary carcinoma invading the trachea. The airway was almost totally obstructed, and tracheal resection and end-to-end anastomosis was planned. A venovenous bypass catheter was placed for cardiopulmonary bypass, using the bilateral femoral veins. Curative surgery and reconstruction were then performed successfully, under general anaesthesia assisted by cardiopulmonary bypass oxygenation.
Cardiopulmonary bypass oxygenation is a safe and effective alternative airway management option in patients with locally aggressive thyroid cancer.