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1

Fifty successful years of the Institute of Plasma Physics, Academy of Sciences of the Czech Republic  

International Nuclear Information System (INIS)

The history of the Czech Institute of Plasma Physics is highlighted. The article is structured as follows: Cyclic accelerators; Interaction of an external high-frequency field and high-temperature plasma - the tokamak; Interaction of an external high-frequency field and high-temperature plasma - pulse plasma systems; Low-temperature plasma - plasma technologies and new materials; Laser plasma - PALS; Optical diagnosis; and Teaching, conferences and international cooperation. (P.A.)

2

Strain effect and characteristics of GaInP/AlGaInP strain-compensated multiple quantum wells  

International Nuclear Information System (INIS)

Ga_0_._6In_0_._4P/(Al_0_._8Ga_0_._2)_0_._4In_0_._6P strain-compensated multiple quantum wells (SCMQW) and Ga_0_._5In_0_._5P/(Al_0_._4Ga_0_._6)_0_._5In_0_._5P unstrained MQW were grown by MOVPE to investigate the shift of photoluminescence (PL) peak wavelength and the carrier lifetime caused by strain effect in SCMQW. The PL peaks of SCMQW and unstrained MQW were 608 and 628 nm, respectively. From the rocking curve of SCMQW, it indicated that the active layers of SCMQW were not zero net strain. The residual strain caused the emission intensity of SCMQW to be about four times weaker than that of unstrained MQW. The carrier lifetimes of SCMQW and unstrained MQW were measured to be 3 and 6.02 ns, respectively. It was conjectured that the residual strain in SCMQW induced a decrease in the carrier lifetime by a factor of two with respect to that of unstrained MQW.

2003-02-15

3

Exciton dissociation effects on time resolved photoluminescence measurements of an Al_0_._5_3In_0_._4_7P/Ga_0_._5_2In_0_._4_8P/Al_0_._5_3In_0_._4_7P-quantum well structure  

International Nuclear Information System (INIS)

Temporal developments of the photoluminescence (PL) intensity at temperatures of 7, 100, and 294 K are analyzed using the rate equations including the exciton dissociation and association terms for an Al_0_._5_3In_0_._4_7P/Ga_0_._5_2In_0_._4_8P/Al_0_._5_3In_0_._4_7P-quantum well structure. At 7 K, the nonexponential time dependence of the PL intensity is caused by the exciton dissociation process. At 7 and 100 K, PL intensity is dominated by the exciton recombination even if the exciton density is smaller than the dissociated carrier density. The thermally excited background carriers affect the recombination processes at 100 and 294 K. At 294 K, the rise part of the PL intensity is dominated by the exciton recombination, though the dissociated carrier density dominates. [copyright] 2001 American Institute of Physics.

2001-06-01

4

The impact of continuing professional development on ophthalmic dispensing of progressive addition lenses in the Asia-Pacific region  

British Library Electronic Table of Contents (United Kingdom)

Background:- Discrepancies exist in optometric education, practice and regulation across the Asia-Pacific region and the competence of optometric practitioners in adopting new lens technologies may vary widely. Over the past 10-years, a continuing professional development program, Varilux Academy Asia-Pacific (VAAP), was implemented and conducted in countries across the Asia-Pacific region to improve practitioners' understanding of optometric fitting principles, with special emphasis on progressive addition lenses (PAL). The aim was to demonstrate the effectiveness of VAAP and to compare the competence of practitioners across the Asia-Pacific region in new lens fitting technologies. Methods:- From 2002 to 2008, all VAAP participants from 12 countries across Asia-Pacific were invited to com...

2011-01-01

5

Smoothing of laser energy deposition by gas jets  

International Nuclear Information System (INIS)

Smoothing of laser beam non-uniformities using gas jets has been studied. The experiment has been performed with the PALS (Prague Asterix Laser System) laser working at 0.44 ?m with an intensity of about 1015 W/cm2. The laser beam has been split in two by a prism thus creating an artificial large-scale non-uniformity (? 90 ?m). We recorded time resolved and static images of laser-gas jet interaction with and without an Al target. Multi 1-dimensional and 2-dimensional simulations show that such interaction acts redistributing the over-intensities over larger surface. This effect has to be attributed to ionization processes with consequent laser beam refraction. Results show that Argon gas jet produces a strong refraction of the laser beam thus strongly reducing the initial two spots separation. (authors)

2009-08-01

6

III-phosphides heterojunction solar cell interface properties from admittance spectroscopy  

International Nuclear Information System (INIS)

GaInP solar cell interfaces were characterized by admittance spectroscopy. Admittance spectroscopy is shown to be sensitive to the band structure at the heterojunction interfaces. In particular, a correlation between activation energy of the capacitance step in a capacitance versus temperature plot and effective potential barrier for majority carriers is demonstrated, indicating a new method for the determination of potential barriers at heterointerfaces. Using this technique, the effective potential barrier for holes at the p-Al_0_._5_3In_0_._4_7P/p-GaAs interface is found to be equal to 0.6 eV. Effects of interface defects and spreading resistance in the emitter of solar cells are illustrated and discussed.

2009-08-21

7

Embedded systems for vacuum control at PEFP  

International Nuclear Information System (INIS)

Development of a front end system for a high energy proton accelerator is in progress at Korea Atomic Energy Research Institute (KAERI) for basic science and industrial applications. The proper vacuum components has been installed and operated successfully between ion source and RFQ. The reliable operation of the accelerator has been completed at vacuum system in the high and ultra high vacuum range under operating conditions. Proper control system for the vacuum instruments, based on PC operated by Windows, has been designed and constructed by control group at PAL. As PC operated by windows with inherent instability does not proper, embedded system can be replaced for reliable operation system, such as VME system operated by vxWorks.

2005-05-26

8

Determination of band offsets and subband levels for a GaInP/AlGaInP quantum well by photoreflectance using a InGaP laser diode  

International Nuclear Information System (INIS)

The band offsets and subband levels in a double quantum well layer for a 660 nm-Ga_0_._4In_0_._6P/(Al_0_._5Ga_0_._5)_0_._5In_0_._5P quantum well laser are determined by photoreflectance using a 410 nm InGaN laser with current modulation at room temperature. The subband levels are analyzed by numerical calculation of the Schroedinger equation for the layer structure by varying the conduction band offset and compared with the measured photoreflectance spectra. The conduction band offset ratio is determined to be 0.5+0.03. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2009-06-01

9

Characteristics and development report for the T1576 power supply and the MC3935 battery  

Energy Technology Data Exchange (ETDEWEB)

This report describes the requirements, designs, performance, and development histories for the T1576 power supply and the MC3935 rechargeable battery. These devices are used to power Permissive Action Link (PAL) ground controllers. The T1576 consists of a stainless steel container, one SA3553 connector, and one MC3935 battery. The MC3935 is a vented nickel/cadmium battery with 24 cells connected in series. It was designed to deliver 5.5 Amp-hours at 25{number_sign}C and the one-hour rate, with a nominal voltage of 28 V. The battery was designed to operate for 5 years or 500 full charge/discharge cycles. The power supply is expected to last indefinitely with replacement batteries and hardware.

1993-10-01