[en] The magnetoresistance (MR) ratio is enhanced by 35% by inserting the nano-oxide layer (NOL) at the Ta/Co interface in the FeMn-based top spin valves (Ta/NOL/Co/Cu/Co/FeMn/Ta). The enhancement is attributed to specular reflection, resulting in a large resistance change and small sheet resistance. However, the formation of NOL at the interface of Ta/Co suppresses the (111) texture, resulting in small exchange fields. Top spin valves with NOLs show good thermal stability up to 200 degreeC annealing. The MR ratio is further increased after annealing at temperatures below 200 degreeC. Enhancement of the MR ratio by 61% can be achieved by annealing at 150 degreeC. For bottom spin valves (Ta/NiFe/FeMn/Co/Cu/NiFe/Ta), NOLs formed at FeMn/Co and NiFe/Ta interfaces increase MR ratios, but NOLs at Co/Cu or Cu/NiFe deteriorate the differential spin scattering and significantly reduce MR ratios. [copyright] 2001 American Institute of Physics

[en] Sacral spinal dural arteriovenous (AV) malformation is rare and its clinical features are not specific to differentiate sacral dural AV malformation from the superiorly located ones. A sacral dural AV malformation, therefore, is usually diagnosed after negative thoracic and lumbar arteriograms. In this report, we propose a myelographic or magnetic resonance (MR) sign of engorged and tortuous intradural filum terminale vein as an indication of a sacral dural AV malformation. When this sign is seen, pelvic arteriography should be performed first

[en] A new technique is described for the study of reactions of carbon with gaseous reactants. The optical absorbance of a thin film of carbon deposited on the surface of a reaction vessel by the pyrolysis of methane was measured in situ using a He-Ne laser. The reaction of the film with oxygen (30-120 Torr, 623⁰C) was followed by continuous monitoring of the absorbance of the film during the complete course of the reaction. The initial rate of reaction of the carbon was first order in oxygen pressure and the activation energy of the rate was 38 kcal/mole. The concentration of strongly-bound complexes on the surface of carbon films was determined from measurements of the yield of carbon monoxide released at 700⁰C after equilibration with oxygen at low temperatures and has been identified with the active surface area (ASA) of the film. The ASA has been measured as a function of the heat treatment and of the percentage conversion of the film. It is shown that both the ASA and the differential rate of gasification increase with increasing conversion of the film. The results are interpreted in terms of a mechanism involving the attack of oxygen molecules on carbon atoms in the neighbourhood of the complex. Changes in the mechanism at high temperatures and low pressures are discussed. (author)

[en] An automatic radiation monitoring system has been developed to continuously in-situ monitor the radioactivity of the service cooling water discharged from the nuclear power plants. The system was designed to be installed just at the site of service water outlet and can sustain the severe sea coast weather. It can continuously sample and detect the water radioactivity down to the regulatory investigation limits set by AEC- In case the monitored water radiation level is above the regulatory limit, this system can automatically save the suspicious water for further analysis. All the monitoring processes and radiation data analysis are controlled by a low cost personal computer. Through the successful development of the PC-based full duplex multiport communication software, this monitoring system can be operated stand-alone or connected to an environmental radiation monitoring network

[en] Heating tumors by nanoparticles and resistance in hypoxic tumor cells to a high temperature is emerging as an effective tool in therapeutic oncology as nanomedicine tool. The art of imaging temperature in a tumor at various locations is emerging as the selective approach of hyperthermia to monitor temperature and treat the tumor. However, thermometry and tumor cell interaction with nanoparticles may monitor and evaluate the tumor cell survival after exposure to high physiological temperatures. The application of 10-100 nanometer sized nanoparticles in tumor hyperthermia has emerged as an effective monitoring tool as magnetic resonance (MR) thermal mapping. The temperature and nanoparticle magnetic moment relationship is specific. Furthermore, there are two main issues that are unsolved as of yet. First issue is the relationship of tumor energy changes due to tumor magnetization; linear attenuation after magnetic field and X-ray exposure with tissue temperature increase. The second issue is the undefined behavior of the nanoparticle inside the tumor as diamagnetic or paramagnetic can be therapeutic and it depends on the tumor tissue temperature. In vivo imaging such as MR thermometry mapping of different hypoxic tumor locations solves these issues to some extent. The art of the nanoparticle-induced hyperthermia does have a great impact on public health as alternative therapeutic oncology.

[en] Owing to the short-lived nuclides present in the decay chain of radon and the complexity of environmental parameters, the behaviour of radon daughters in the environment is rather complicated. Therefore, errors are easily induced in the measurements of radon daughters. In this investigation 10 methods developed by several investigators compiled as a software package were reviewed and tested one by one in a radon environment with known concentrations. The Alpha Smart 770 of Alpha Nuclear Canada was used to evaluate and make comparisons among these ten methods. Consistent results within an error of 6% were obtained for six methods. However, inconsistent results within an error of from 24% up to a factor of 4 were obtained for the other four methods. It is concluded that the method to be used should be evaluated before routine or large-scale sampling is planned. (author)

[en] Digital Elevation Model (DEM) often makes it difficult for terrain reconstruction and data storage due to the failure in acquisition of details with higher resolution. If original terrain of DEM can be simulated, resulting in geographical details can be represented precisely while reducing the data size, then an effective reconstruction scheme is essential. This paper adopts two sets of real-world 3D terrain profile data to proceed data reducing, i.e. data sampling randomly, then reconstruct them through 3D fractal reconstruction. Meanwhile, the quantitative and qualitative difference generated from different reduction rates were evaluated statistically. The research results show that, if 3D fractal interpolation method is applied to DEM reconstruction, the higher reduction rate can be obtained for DEM of larger data size with respect to that of smaller data size under the assumption that the entire terrain structure is still maintained.

[en] A high-throughput Protein Crystallography beamline BL13B1 was constructed on a high-field (3.2 T) superconducting magnet, multi-pole (28 effective poles) wiggler (SW6) fan of the NSRRC storage ring. This field increase the critical energy from 2.14 keV for a 1.25 T normal conducting magnet to 4.82 keV. The 28 poles device, of period 60 mm, is capable to provide an intense X-ray beam up to 19 keV that allows a hard x-ray program to be developed on the relatively low energy National Synchrotron Radiation Research Center (NSRRC) ring (1.5 GeV). BL13B1 operates over the energy range from 6.5 keV to 19 keV (1.92 angstrom to 0.65 angstrom). Optimized for MAD experiments, it is also suitable for monochromatic crystallography. The principal components of the beamline include a front end, vertically collimating premirror, double-crystal silicon (111) monochromator with a fixed-height exit beam, and a toroidal focusing mirror. The end station is equipped with a state-of-the-art ADSC Quantum315 CCD area detector, a high precision single-phi axis goniometer, a sample cooling system (∼100 K), a robotic sample changer for automatically sample mounting and centering, user-friendly data acquisition software (BLU-ICE), and powerful data processing software (HKL2000). The design and performance characteristics of this beamline will be described

[en] The recent status of the SPring-8 Taiwan Contract Beamline BL12B2 is reported. The beamline was designed to provide multiple applications for materials and biological researches. It is equipped with four end stations, including an EXAFS station, a Huber 6-circle diffractometer for X-ray scattering, a curved image plate for the studies of powder diffraction, and a station for the protein crystallography. The beamline construction was completed in 2000 and it has been in full speed operation since September 2001. To enhance the focusing capacity, the beamline optics has been modified in 2002 and a gain of factor of 10 in photon flux was consequently obtained at protein crystallography station

[en] The electronic structures of five polycrystalline YNi_2-xCo _xB₂C (x = 0, 0.05, 0.1, 0.15, and 0.2) borocarbide superconductors were studied by photoemission and photoabsorption spectroscopy. The resonant photoemission spectroscopy around the Ni 2p_3/2 absorption edge is used to study the 6-eV valence-band satellite of Ni. The Ni and Co K-edge X-ray absorption near edge spectra for these intermetallic compounds are compared with those of Ni and Co powder and foil, respectively