[en] Silicon single crystals were implanted with 100 keV phosphorus ions to a dose of 2 x 10¹⁶ ions/cm² at both room-temperature and 600⁰C. They were isochronally annealed at temperatures ranging from 400⁰C to 900⁰C. Sheet resistivity measurements of the specimens were taken after each anneal, together with corresponding transmission electron micrographs

[en] We present the preparation and characterization of thin films of several carbon-based compounds. Boron carbide films were prepared by pulsed laser deposition (PLD) in vacuum using sintered B₄C as raw material. In the environment of an ECR nitrogen plasma and with bombardment by the low-energy plasma stream, carbon nitride films were prepared by ablating a graphite target, while a sintered B₄C target was used to prepare thin films of boron carbon nitride (BCN). The prepared films with smooth surface were found to be adhesive to the substrates and contain several chemical bonds with atomic hybridization rather than a simple mixture of B-N, B-C and C-N phases. Pulsed laser ablation of the target is efficient for the target material to be transferred to a nearby substrate. For nitride film preparation, the assistance of the reactive ECR nitrogen plasma is responsible for nitrogen incorporation and favorable for nitride formation

[en] The corner cube mixers originally developed for the TEXT-U far-infrared interferometer were susceptible to damage by tokamak radiation. The source of the damage has been traced to intense ω_pe bursts emitted by the tokamak during start-up. The authors have determined that this radiation was coupled into the detector through a small gap in the original design. An electromagnetic model has been used to calculate the electric field distribution within the gap. Results are consistent with the expected power in a burst

[en] Monitoring of light-element concentration in steel is very important for quality assurance in the steel industry. In this work, detection in open air of trace phosphorus (P) in steel using laser-induced breakdown spectroscopy (LIBS) combined with laser-induced fluorescence (LIF) has been investigated. An optical parametric oscillator wavelength-tunable laser was used to resonantly excite the P atoms within plasma plumes generated by a Q-switched Nd:YAG laser. A set of steel samples with P concentrations from 3.9 to 720 parts in 10⁶(ppm) were analyzed using LIBS-LIF at wavelengths of 253.40 and 253.56 nm for resonant excitation of P atoms and fluorescence lines at wavelengths of 213.55 and 213.62 nm. The calibration curves were measured to determine the limit of detection for P in steel, which is estimated to be around 0.7 ppm. The results demonstrate the potential of LIBS-LIF to meet the requirements for on-line analyses in open air in the steel industry.

[en] The design of a new class of focused microwave applicators for inducing hyperthermia is studied. The applicator consists of an electrically large antenna that produces a focused beam at the tumor. For treating tumor 4 cm into the body, our theoretical baseline design consists of an operating frequency at 1500 MHz, an aperture dimension of 15 cm and a matching dielectric with dielectric constant of 50. Assuming that a nominal power density of 100 mW/Cm/sup 3/ is required at the tumor to achieve hyperthermia, the above design requires only 30 W of input power whereas 650 W is needed for an incident collimated beam of the same frequency. In addition, the surface heating from such a focused applicator is 6 dB lower than that from a collimated beam. The continuous aperture model used in the present study may be implemented by a discrete array of 19 waveguide horns. When transmitting through an irregular body contour, the phases of array elements are set by the so-called ''conjugate field matching'' scheme. The authors insert a small radiating probe into the body at a prescribed focus, and use the array applicator as a receiving antenna. Next the array is excited by the conjugate of the received field in each element. By reciprocity, the radiated field from the array is focused at the focus

[en] We present a new dc superconducting quantum interference device (SQUID) configured as a susceptometer for the study of the magnetic properties of small (<10 μm) particles and thin-film samples. The SQUID consists of two series pick-up loops wound in opposite sense over a hole in the groundplane and connected to remotely located tunnel junctions by low inductance transmission lines. An integrated field coil with provision for balance allows application of a magnetic field of 0--30 G to a sample positioned in either pick-up loop. For an applied field of 5 G the device having an intrinsic energy sensitivity of approx.25 h is able to resolve the superconducting transition of a 5-μm tin particle with a signal-to-noise ratio of approx.10⁶

[en] The Magenstrasse and Mill (M and M) procedure for obesity is designed to preserve normal gastric emptying mechanisms. The hypothesis investigated in this study was that gastric emptying would be normal after the M and M gastroplasty. Gastric emptying studies were performed using both liquid and solid test meals, in ten morbidly obese patients (MO group) and in 13 patients after the M and M procedure (MM group). Seven people of normal weight served as controls and were matched for age, sex and height to the M and M and MO groups. Three years after the M and M procedure, mean (SD) weight loss was 42 (19) kg, with a mean loss of excess weight of 58% (20%). Gastric emptying half-times (t_1/2) are expressed in minutes, as median values (25th and 75th percentiles). The t_1/2 for solids was 97 (85-110) min in the control group, 140 (86-220) min in the MO group and 79 (46-150) min in the MM group. Median gastric emptying for solids was 0.7% (0.6%-0.8%) per minute in the control group, 0.5% (0.3%-0.8%) in the MO group and 0.9% (0.4%-1.4%) in the M and M group. There were no statistically significant differences in the emptying times of the three groups. It is concluded that the M and M procedure achieves acceptable weight loss, while preserving gastric emptying mechanisms and thus minimising possible side-effects such as vomiting, dumping and diarrhoea, which are common complications of gastric bypass procedures. (orig.)

[en] A configuration is described to measure the effect of the plasma produced by an arcjet thruster on a reflector antenna. The diagnostic consists of a small movable rf probe coupled to a Hewlett--Packard 8510 network analyzer. Because the perturbation is expected to be small (<10 degree phase shift), wall reflections are an important consideration. To minimize their effect we use Fourier transform gating techniques

[en] The spatial confinement effects in laser-induced breakdown of aluminum (Al) targets in air have been investigated both by optical emission spectroscopy and fast photography. A KrF excimer laser was used to produce plasmas from Al targets in air. Al atomic emission lines show an obvious enhancement in the emission intensity when a pair of Al-plate walls were placed to spatially confine the plasma plumes. Images of the Al plasma plumes showed that the plasma plumes evolved into a torus shape and were compressed in the Al walls. The mechanism for the confinement effects was discussed using shock wave theory

[en] The cylindrical confinement of laser-induced plasmas in round pipes has been investigated by optical emission spectra and fast imaging. An obvious enhancement in the emission intensity of Al atomic lines was observed when a round pipe was placed to confine the laser-induced Al plasmas. The enhancement factor for the emission intensities of the Al atomic lines was measured to be around 9 at a time delay of 12 μs when the pipe diameter is 10.8 mm. Assuming local thermodynamic equilibrium conditions, the plasma temperatures are estimated to be in the range from 4000 to 5800 K. It shows that the plasma temperature increased by around 1000 K when the cylindrical confinement was applied. Images of the laser-induced Al plasmas show that the plasmas were compressed into a smaller volume with a pipe presented. The spatial-confinement effects are attributed to the reflection and compression of the shock wave