[en] The one-electron reduction of 4,7-phenanthroline (P) in aqueous solutions at neutral pH has been further studied by pulse radiolysis. The spectral and kinetic properties of the transient formed due to the reaction of 4,7-phenanthroline with hydrated electron were investigated. The transient absorption spectrum obtained 5μs after the pulse exhibits a broad band with a λ_max at 420 nm. The λ_max is 10 nm blue shift compared with the absorption spectrum obtained at pH 2.9 where the reactant was the protonated form. The bimolecular rate constant of the reaction of 4,7-phenanthroline with hydrated electron was determined to be (2.2±0.1)x10¹⁰ dm³ mol^-1 s^-1. It was found that the decay of the transient was mainly following a first-order kinetics. The first-order decay rate constant was determined to be (1.25±0.1)x10⁴ s^-1

[en] The primary processes of radiation chemistry in polymers have been studied by using a picosecond synchrotron radiation pulse radiolysis system combined with one of the Accumulation Ring beam lines of the TRISTAN accelerators of KEK. The pulse radiolysis is one of the most powerful methods to study the reaction mechanisms of intermediates, such as ions, excited states, and radicals. X-ray induced polymer reactions have not been studied yet by pulse radiolysis technique. The emission from solid polymers such as polystyrene have been observed at room temperature, and the reaction mechanisms have been discussed by comparing with other data in polymers irradiated by electrons and heavy ions

[en] This paper reports on thin film Josephson junctions used as infrared detectors' which function by a thermal sensing mechanism. In addition to the potential for high sensitivity to a broad range of optical wavelengths, they are ideally suited for integration with superconducting electronics on a single wafer. A project at HYPRES to develop these arrays is directed along two avenues: maximizing the sensitivity of individual Josephson junction detector/SQUID amplifier units and development of superconducting on-chip processing circuitry - multiplexers and A to D converters

[en] PIXE analysis is applied to investigate a long-term disputed issue whether the rare earth element (REE) can enter the cell across the cell membrane or not. It has been illustrated that REE could travel across the biomembrane into the cells by cell studies in vitro as well as in studies of animals fed with REEs diet. The binding of REE by membrane changes its permeability and makes intracellular ion transportable. Entrance of REEs may influence the cellular function. In addition, the REE distribution and behavior in cell are discussed

[en] Complete text of publication follows. A mild pre-irradiation method was used to graft glycidyl methacrylate (GMA) onto polyethylene (PE) non-woven fabric. The polymer was irradiated by electron beam at a voltage of 1.8 MeV and a current of 2 mA in air atmosphere at room temperature. The degree of grafting (D_g) was determined as a function of reaction time, irradiation dose, monomer concentration and temperature. After 30 kGy irradiation, with 5% GMA, the surfactant Tw-20 of 0.5% at 55 deg C for 15 min, the trunk polymer was made grafted at a D_g of 150%. Selected PE-g-PGMA of different D_gs was modified with such compounds as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylene pentamine (TEPA). The obtained amine-type adsorbents were prepared specialty for the further removal of copper and uranium from solution. It was shown that at least 90% 1 ppm copper and 60% uranium with the initial concentration from 3 to 1000 ppb can be removed from water.

[en] The formation of trace moisture by exposure of dry heated surfaces of 316 L stainless-steel, Restek Silcosteel registered , and nickel 1/8 in. outer diameter line segments to purified Ar and H₂ was studied using atmospheric pressure ionization mass spectrometry at flow rates of 2 slpm. Prior to H₂ exposure, adsorbed moisture was removed by heating incrementally to 500 deg. C in an argon matrix, where the Restek Silcosteel registered material released a maximum of 50 ppb moisture at 300 deg. C and moisture spikes from the Ni and stainless-steel surfaces reached several 100 ppb. Upon exposure to H₂, persistent low ppb moisture emissions due to the reduction of surface oxide species were observed at temperatures as low as 100 deg. C. Spikes at 300-500 deg. C ranged from ∼100 ppb for the stainless-steel lines to 400 ppb for the Restek Silcosteel registered material. The observed moisture emissions have to be considered as a potential contamination source for high-purity processes utilizing H₂ purge at elevated temperatures

[en] Trace amount Ca-doped TiO_2 films were synthesized by the hydrothermal method and applied as photoanodes of dye-sensitized solar cells (DSSCs). To prepare Ca-doped TiO_2 film electrodes, several milliliters of Ca(NO_3)_2 solution was added in TiO_2 solution during the hydrolysis process. The improvements of DSSCs were confirmed by photocurrent density-voltage (J-V) characteristics, electrochemical impedance spectroscopy (EIS) measurements. Owing to the doping effect of Ca, the Ca-doped TiO_2 thin film shows power conversion efficiency of 7.45% for 50 ppm Ca-doped TiO_2 electrode, which is higher than that of the undoped TiO_2 film (6.78%) and the short-circuit photocurrent density (J-s_c) increases from 13.68 to 15.42 mA .cm"-"2. The energy conversion efficiency and short-circuit current density (J-s_c) of DSSCs were increased due to the faster electron transport in the Ca-doped TiO_2 film. When Ca was incorporated into TiO_2 films, the electrons transport faster and the charge collection efficiency (η_C_c) is higher than that in the undoped TiO_2 films

[en] In this study, the microstructure and stability of precipitates in Zr-2.5Nb-0.5Cu alloy under heavy ion irradiation was investigated. Results show that three types of microstructure co-exist in the alloy: Widmansttatten structure, α-Zr grains without precipitates and α-Zr grains with precipitates. In the meantime, three types of second phase particles are detected: β-Nb, Zr₂Cu and Zr₂Fe, which have different distributions within the microstructure. The structure has significant effects on the precipitate stability under irradiation. The precipitates are much more stable in microstructures with multiple boundaries (martensitic structure) than in coarse grain microstructures. (author)

[en] Purpose: To evaluate the efficacy of adding accelerated fractionation after completing two thirds of routine fractionated radiotherapy in esophageal carcinoma.Methods and materials: From April 1988 to April 1990, 85 patients with histologically confirmed carcinoma of the esophagus were randomized into two groups. (1) The conventional fractionation (CF) group, received 1.8 Gy per day five times a week to a total dose of 68.4 Gy in 7-8 weeks, and (2) the late course accelerated hyperfractionated (LCAF) group which received the same schedule as the CF group during the first two thirds of the course of radiotherapy to a dose of 41.4 Gy/23 fx/4 to 5 weeks. This was then followed by accelerated hyperfractionation using reduced fields. In the LCAF portion of the radiotherapeutic course, the irradiation schedule was changed to 1.5 Gy twice a day, with an interval of 4 h between fractions, to a dose of 27 Gy/18 fx. Thus the total dose was also 68.4 Gy, the same as the CF group, but the course of radiotherapy was shorter, being only 6.4 weeks. The same Cobalt 60 teletherapy unit was used to treat all the cases.Results: The 5 year actuarial survival and disease-free survival rates in the LCAF group were 34% and 42%, as compared to 15% and 15% respectively in the CF group, all statistically significant. Better local control was seen in the LCAF group than in the CF group, the 5 year control rates being 55% versus 21% (P=0.003). The acute reactions were increased but acceptable in the LCAF patients, the radiation treatments could be completed without any breaks. The late reactions as observed after 5 years were not increased in comparison with the CF patients.Conclusions: The results from this study show that the late course accelerated hyperfractionated radiotherapy regime can improve results in esophageal carcinoma, with acceptable acute reactions as compared to conventional radiotherapy. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

[en] In the upgrade of ATLAS experiment [1], the front-end electronics components are subjected to a large radiation background. Meanwhile high speed optical links are required for the data transmission between the on-detector and off-detector electronics. The GBT architecture and the Versatile Link (VL) project are designed by CERN to support the 4.8 Gbps line rate bidirectional high-speed data transmission which is called GBT link [2]. In the ATLAS upgrade, besides the link with on-detector, the GBT link is also used between different off-detector systems. The GBTX ASIC is designed for the on-detector front-end, correspondingly for the off-detector electronics, the GBT architecture is implemented in Field Programmable Gate Arrays (FPGA). CERN launches the GBT-FPGA project to provide examples in different types of FPGA [3]. In the ATLAS upgrade framework, the Front-End LInk eXchange (FELIX) system [4, 5] is used to interface the front-end electronics of several ATLAS subsystems. The GBT link is used between them, to transfer the detector data and the timing, trigger, control and monitoring information. The trigger signal distributed in the down-link from FELIX to the front-end requires a fixed and low latency. In this paper, several optimizations on the GBT-FPGA IP core are introduced, to achieve a lower fixed latency. For FELIX, a common firmware will be used to interface different front-ends with support of both GBT modes: the forward error correction mode and the wide mode. The modified GBT-FPGA core has the ability to switch between the GBT modes without FPGA reprogramming. The system clock distribution of the multi-channel FELIX firmware is also discussed in this paper.