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β-Ga2O3 is a well-known semiconductor material for power devices and other applications. Recently, β-Ga2O3 has also been reported as a scintillator material with a light yield of approximately 8400 ph./MeV, scintillation decay time of 3. In this study, 45 cm diameter β-Ga2O3 single crystals were prepared via oxide crystal growth using the cold crucible (OCCC) method under various oxygen partial pressures. In the OCCC method, as in the cold crucible method, a high frequency is applied directly to the oxide materials, which are heated and melted, and the melt is held by the outermost solid material itself that is cooled by water using a copper hearth. In the OCCC method, crystal growth is performed while rotating the seed crystal, as in the Czochralski method, to increase the crystal diameter. The optical properties and radiation responses of the crystals grown under various oxygen partial pressures were evaluated.

A novel single-crystal growth method was developed, using arc plasma and metal melt, for a quick survey of high melting point materials. Single crystals of Yb-doped Lu2O3, Lu0.388Hf0.612O1.806, and Lu0.18Hf0.82O1.91, with melting points of 2460, 2900, and 2840 °C, respectively, were grown by an indirect heating method using arc plasma. We refer to this indirect heating growth method as the core heating (CH) method. The CH-grown Yb1%-doped Lu2O3 sample showed a full width at half maximum of 286 arcsec in the X-ray rocking curve. This value is better than the 393 arcsec obtained for the crystal grown by the micro-pulling-down (μ-PD) method. The Yb charge transfer state (CTS) emission was observed at 350 nm in the Yb1%-doped Lu2O3 and Lu0.18Hf0.82O1.91. In the case of the μ-PD method, using a rhenium (Re) crucible, absorption due to Re contamination and a resulting reduction in the Yb CTS emission were confirmed. However, contamination did not influence the properties observed in the crystals grown by the CH method.

Ce-doped LaBr3/AEBr2 (AE = Mg, Ca, Sr, Ba) eutectics were grown using the Bridgman–Stockbarger (BS) method in quartz ampoules. The eutectics (AE = Mg and Ca) showed optical transparency like optical fiber bundles. A grown Ce-doped LaBr3/MgBr2 eutectic shows a 355 nm emission ascribed to Ce3+ 4f-5d transition under X-ray excitation. The smaller the ionic size of AE, the higher the light yield of the sample was. The light yield of Ce:LaBr3/MgBr2 was 34,300 photon/MeV, which is higher than Ce:LYSO standard. Scintillation decay time under 662 keV gamma-ray excitation was 18.8 ns.

Background/Objective: Recently, endoscopic and radiological procedures for various symptoms related to cirrhosis have improved. Thus, the role of Hassab's operation (gastroesophageal decongestion and splenectomy) has changed for cirrhotic patients. Methods: Hassab's operation was performed on patients who had gastroesophageal varices that were difficult to control with balloon occluded retrograde transvenous obliteration or an endoscopic procedure, or had hypersplenism. Thirteen consecutive patients underwent this operation, and the outcomes of all patients were reviewed retrospectively. Results: There was no operative morbidity or rebleeding varices. In the preoperative endoscopic injection sclerotherapy treated group (n=6), only one patient (16.7%) developed recurrent varices. Mean platelet counts were significantly higher 6 months after surgery (201±65×103/mm3) than preoperatively (64±54×103/mm3). In patients with hepatocellular carcinoma, percutaneous therapies, such as radio frequency ablation, were safely performed with adequate therapeutic effect. Interferon therapy was given to patients with hepatitis C virus (HCV)-related cirrhosis without interruption. Conclusion: Hassab's operation is a satisfactory approach to controlling varices, especially when combined with preoperative endoscopic treatment. Platelet counts were significantly higher after surgery. This therapy was important for cirrhotic patients contraindicated for liver transplantation in that they could continue their therapy for hepatocellular carcinoma (HCC) and HCV as needed.

BACKGROUND: Acute otitis media (AOM) is one of the most common forms of bacterial infection and cause for clinic visits in children. The incidence of AOM was 0.9-1.2 episodes per person-year during the first 2 years of life in previous reports conducted before 2000. The aim of this study was to 1) evaluate the latest AOM incidence in pediatric outpatients and 2) identify the bacterial pathogens from these patients and ascertain their serotypes and resistance. METHODS: The study was conducted in a closed population, involving all pediatricians and otolaryngologists in Sado Island allowing accurate determination of AOM incidence. In each month, one week was assigned as "surveillance week", and all outpatients with acute illness aged 0-18 years examined during the surveillance weeks were enrolled. AOM was diagnosed on the basis of otoscopic findings and clinical symptoms were recorded. Specimens were collected from the nasopharynx or middle ear cavity of AOM patients and examined for bacteria. Antimicrobial susceptibilities, serotypes, and molecular typing for resistance were determined among Streptococcus pneumoniae and Haemophilus influenzae. RESULTS: In total, 8,283 clinic visits were conducted, and 354 episodes (4.3%, 95% CI: 3.9-4.7%) among 312 children were diagnosed as AOM. The incidence of AOM was highest in children of 1 year of age (0.54 episodes/child/year, 95% CI: 0.44-0.64). Serotype coverage of 7- and 13-valent pneumococcal conjugate vaccines in this study were 38.0% (95% CI: 29.3-47.3) and 62.8% (95% CI: 53.6-71.4), respectively. Of 122 H.influenzae isolates available for typing, 120 were nontypeable and 2 were type b. A high proportion of S. pneumoniae isolates (46%) showed resistance to penicillin. Approximately half of H. influenzae isolates had genetic markers for beta-lactamase-negative ampicillin-resistance. CONCLUSIONS: Approximately 4-5% of pediatric outpatients, even without AOM-related symptoms, had AOM in our study. Pediatricians as well as otolaryngologists should check the tympanic membrane findings of all pediatric outpatients.

In this study, a singularity-free trajectory generation algorithm of the roof-type control moment gyro (CMG) system consisting of four CMGs is proposed. Under the condition that the total angular momentum is conserved at zero, by selecting the initial gimbal angles according to the direction of the angular momentum by the roof-type CMG system, the singularity is avoided in total angular momentum space, over the wide range of the magnitude of the initial gimbal angle except near the Z-axis. The effectiveness of the algorithm is confirmed by numerical calculations, and a PD-like control using the gimbal trajectory is proposed, which is also verified by numerical simulations. [ABSTRACT FROM AUTHOR]

This study investigates the attitude rate damping control of a stratospheric balloon gondola using three-axis momentum-exchange devices, which are mounted on the gondola. To this end, we propose a steering law considering four single-gimbal control moment gyros. The stratospheric balloon system can be modeled as a three-rigid-body system comprising a balloon, gondola, and suspension string connecting the gondola with the balloon. Based on this model, the target torque for the rate damping control is derived from Lyapunov’s stability theorem. We propose the analytical solution of time evolutions for the deflection of the suspension against the balloon and the mechanical energy of the stratospheric balloon system under control. Numerical simulations demonstrate that mechanical energy monotonically decreases. Moreover, the accuracy of the analytical solutions is also demonstrated. [ABSTRACT FROM AUTHOR]

This paper considers a rest-to-rest spacecraft attitude maneuver using two variable-speed control moment gyros. Two methods are used to derive angular momentum and gimbal angles over time subject to physical constraints. The first is an analytical method using variational calculus: from the analytical solution the dynamic characteristics of the attitude maneuver are easily understood and feasible trajectories are derived. The second is a numerical method which uses a Chebyshev pseudospectral method. The maneuvering time is minimized by the numerical method. In this second method, it is difficult to obtain a solution without appropriate initial values. However, a solution can be derived by using an analytical solution as initial values. The analytical and numerical methods are executed in all directions of the attitude maneuver, thus validating the effectiveness of the successful completion of the intended maneuver. Finally, ground experiments are conducted using the optimal trajectories obtained by the numerical method. [ABSTRACT FROM AUTHOR]

This study addresses the control method of the azimuth direction of a stratospheric balloon gondola with simple and low-cost system. Many azimuthal control methods of the gondola have been developed mainly to achieve accurate pointing of astronomical observation instruments. As progress of technology, such systems have become complicated and expensive. On the other hand, as variety of balloon mission increasing, demands for azimuthal control system with rough accuracy, simple and small system, and low cost are also rising recently. This study proposes an azimuth control method with only a motored decoupler. The motored decoupler is an attitude control device to twist and untwist the suspension not to transfer torsion torque of the suspension and the rotation of the balloon envelope. However, the mechanism can also be used to generate torsion torque for azimuthal control of the gondola. This study aims to achieve the azimuthal control capability with the motored decoupler. The control law with observable parameters was derived by linear quadrant regulator (LQR) method. The control law was evaluated by some numerical simulations. As the result, the proposed method is concluded useful for actual balloon missions. [ABSTRACT FROM AUTHOR]

We grew 1.5-in Eu doped SrI2 (Eu:SrI2) bulk single crystal by a modified vertical Bridgman (VB) method using a removable chamber and high-frequency induction heating. As-grown 1.5-in Eu:SrI2 bulk single crystal had no visible crack and inclusion in the crystal. In the transmittance and $\alpha $-ray radioluminescence spectra, large absorption below 433 nm and emission peak at 433 nm were observed, respectively. Each polished 56 \thinspace 000 \sim 62 \thinspace 000\ \ph/MeV light yield and 3.3 \sim 3.9\%$ energy resolution. The decay times of the specimens were 0.61 \sim 0.67\ \mu \s. [ABSTRACT FROM AUTHOR]

This paper reports the balloon borne telescope named FUJIN-2 which is being developed for the optical observation of planets with better quality and longer continuity than observations by existing observation methods. The project has already developed prototypes for the domestic flight test, and it proceeds the status to the development of the flight system for the long duration flight around the north pole. In this article the science mission overview and the advantages is addressed first. Then the new flight system for the long duration flight is introduced. In the latter of the article a result of the performance evaluation ground test which is the base of the design of the new flight system is reported. [ABSTRACT FROM AUTHOR]

In this study, the performance of rate damping control from a control moment gyro is investigated. Two types of wheel angular momentum (variable and constant) and two quantities of gimbal axes (one or two) are considered. When the angular momentum of the spacecraft body is fully absorbed by the wheel, the rate damping of the spacecraft can be achieved. In contrast, for cases of with constant wheel speed, the rate damping of the spacecraft body cannot be achieved. The steady state analysis of the rate damping control in these cases shows the stationary value of the angular velocity of the spacecraft. Numerical simulations verify the analytical results. [ABSTRACT FROM AUTHOR]

The effects of Mg co-doping on the scintillation properties of Ce:Lu2Gd1(Ga,Al)5O12 (LGGAG) single crystals with different Ga/Al ratios were investigated. Mg co-doped and non co-doped Ce:LGGAG single crystals were grown by the micro-pulling down (µ-PD) method and then cut, polished and annealed for each measurement. Absorption spectra, radioluminescence (RL) spectra, pulse height spectra, and scintillation decay were measured to reveal the effect of Mg co-doping. Ce4+ charge transfer (CT) absorption band peaking at ∼260 nm was observed in Mg co-doped samples, which is in good agreement with previous reports for the Ce4+ CT absorption band in other garnet-based crystals. The scintillation decay time tended to be accelerated and the light yield tended to be decreased by Mg co-doping at higher Ga concentrations. [ABSTRACT FROM AUTHOR]

The temperature dependences of the acoustic properties of Ca3Ta(Ga1−xAlx)3Si2O14 [CTGAS(x)] were experimentally studied as a function of the Al substitution content x. Five specimens, i.e., one each of X-, Y-, and Z-, and two rotated Y-cut specimens, were prepared from each crystal ingot of CTGAS(x) (x = 0, 0.25, 0.50, and 0.75) grown by the Czochralski technique. The longitudinal wave and shear wave velocities of CTGAS(x) were measured at three temperatures ranging from 291 to 300 K, then acoustically related physical constants (elastic, piezoelectric, and dielectric constants and coefficient of thermal expansion) were determined at approximately room temperature. The results revealed that the temperature coefficients of all the constants linearly changed with Al content. By one of the calculations using the constants and their temperature coefficients determined in this study, we demonstrated their capability to predict suitable conditions (i.e., cut angle, propagation direction, and chemical composition) for acoustic wave devices although they were determined in a narrow temperature range. [ABSTRACT FROM AUTHOR]

The acoustic properties of Ca3Ta(Ga1−xAlx)3Si2O14 (CTGASx) were experimentally studied as a function of the Al substitution content x in the ranges from x = 0 to 0.50. Five specimens, X-, Y-, Z-, 35°Y-, and 140°Y-cut, were prepared from each crystal of CTGASx (x = 0, 0.25, and 0.50) grown by the Czochralski technique. Longitudinal wave and shear wave velocities for CTGASx linearly increase with Al content for all propagation directions. Dielectric constants and density were measured and then elastic and piezoelectric constants were determined from the measured velocities for each crystal. The results revealed that all of the constants change linearly with Al content. From the relationship, the constants for CTAS (x = 1) were estimated. Calculations of the velocities using the determined constants also suggested that the maximum electromechanical coupling factor k2 for the slow shear wave mode propagating along the rotated Y-axis direction of CTAS was improved to 4.42% compared with 3.83% for CTGS, owing to the Al substitution effect. [ABSTRACT FROM AUTHOR]

Scintillation properties of a Pr-doped gadolinium lanthanum pyrosilicate (Pr:La-GPS) crystal grown by the floating zone (FZ) method were investigated, because the Pr3+ 5d–4f transition is expected to show a shorter decay time than the Ce3+ 5d–4f transition. In both α-ray radioluminescence and photoluminescence spectra, the emission peak related to the Pr3+ 5d–4f transition was observed at around 350 nm. The photoluminescence decay time of Pr:La-GPS was found to be as short as ∼23 ns, whereas Ce:La-GPS had a decay time of ∼31 ns. [ABSTRACT FROM AUTHOR]