Vol.19,

Multilayer polarization elements and their applications to polarimetric studies in 20~400 eV region are mainly reviewed. General principle of selecting material combinations to get high linear polarizance multilayers of reflection type is given with practical examples, with periodic or non–periodic layer structures depending on the usage. Transmission type is introduced as linear polarizer and phase shifter. Their applications include polarization diagnosis of laboratory optical systems and synchrotron radiation beamlines of linear and circular polarization, magnetic rotation experiments such as Faraday rotation and magnetic Kerr rotation on magnetic films and multilayers, and ellipsometry to measure optical constants of thin films precisely. Polarization analysis of soft X-ray fluorescence using multilayer-coated grating is also mentioned. Finally this review is summarized with outlook of further developments.

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The Shanghai Synchrotron Radiation Facility (SSRF) is a low emittance third-generation synchrotron radiation light source under commissioning. The excitation curve calibration for the booster magnets is important to provide the magnet current configurations as reference. Calibration studies give the polynomial coefficients of each type of magnets and provide the magnet current configurations under different beam energies as beam is ramped at speed of 2 Hz. The applications of calibration in booster commissioning which show the accuracy of the magnetic excitation curve calibration are also discussed.

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The dynamics of transportation, accumulation, disappearance and distribution of ⁶⁰Co in a simulated aquatic–terrestrial ecosystem was studied by isotope-tracer technique. In the aquatic system, ⁶⁰Co was transported and transformed via depositing, coupling with ions and adsorption. The absorption resulted in the redistribution and accumulation of ⁶⁰Co in each compartment of the system. Specific activities of ⁶⁰Co in water started sharply and gently decreased. The sediment accumulated a large amount of ⁶⁰Co by adsorption and ion exchange. The hornwort (Ceralophyllum demersum) could also adsorb a large amount of ⁶⁰Co in a short time, because of its large specific surface area. Fish (Carassius auratus) and snail (Bellamya purificata) had a poor capacity of adsorbing ⁶⁰Co. The distribution of ⁶⁰Co in the fish was mainly in the viscera, and the amount of ⁶⁰Co in the snail flesh was greater than that in the shell. The amount of ⁶⁰Co in individual compartment in the system was changed with time. The highest specific activity of ⁶⁰Co in the bean of the terrestrial system remained in the root nodule.

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The rate of elapsed polymerization of polyhydroxyethylacrylate in gelatin has been studied to investigate the effect of co-monomers consumption at a given dose. The polymer gel dosimeters consisted of 2%~4% N,N-methyelene-bis-acrylamide cross-linker, 2%~4% 2-hydroxyethylacrylate monomer and gelatin at 3% and 5%. The dosimeters were irradiated by using ⁶⁰Co teletherapy γg-ray source up to 20 Gy at a constant dose rate. The relaxation rate of water proton in the dosimeters at different doses and co-monomer concentrations were measured using a nuclear magnetic resonance spectroscopy. The rate of elapsed polymerization decreases with increasing the dose and the initial concentration of co-monomers. The rate of consumption of co-monomers increases with an increase of the polymerization and the gelatin content of the polymer gel.

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Two new nitrido-¹⁸⁸Re complexes were prepared by a modified method in high yield. These complexes were stable in vitro. The biodistribution in normal mice showed that these nitrido-¹⁸⁸Re complexes could accumulate in liver and dissipate quickly from almost all organs. TAE was performed with the use of lipiodol solutions of two complexes to rabbit VX2 liver tumor models. SPECT images showed that the two lipiodol solutions could remain in tumor for about 9 h (¹⁸⁸ReN-NEPTDD/lipiodol) and 12 h (¹⁸⁸ReN-NEMMPTDD/lipiodol), respectively.

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This work is to study the in vivo biological distribution of ¹³¹I-labeled mouse/human chimeric monoclonal antibody (¹³¹I-chTNT) in patients with pulmonary metastases from differentiated thyroid carcinoma. Ten patients with differentiated thyroid carcinoma were injected intravenously with a single dose of ¹³¹I-chTNT (5 MBq·kg^-1 body weight). Radioactivity of blood and urine samples was measured at different time points. The in vivo stability and the metabolic status of ¹³¹I-chTNT were detected with supersaturated trichloroacetic acid. Continuous imaging was performed to outline the region of interest (ROI) and estimate the intake level on the whole body, major organs and tumor lesions at different time points. The serum time-radioactivity curve of ¹³¹I-chTNT accorded with the two-compartment model after a single intravenous injection: T_1/2(h)=65.28±14.83, AUC_0-t(MBq·h·mL^-1)=8.93±1.32, AUC_0-∞(MBq·h·mL^-1)=10.58±2.19, and CL(mL·min^-1·kg^-1)=1635±359. The time-radioactivity percentage curve of ¹³¹I-chTNT urine excretion accorded with the one-compartment model after a single intravenous injection: T_1/2(h)=99±10, and accumulative (31±9) % radioactivity of the injected dose was excreted in urine in one week. The percentages of serum ¹³¹I-chTNT in radioactive components at 24, 48 and 72 h were over 95% and it was still (88±7) % at 168 h. As for chemical composition of radioactive substances in urine, radioactivity in urine samples originated from free ¹³¹I by 100%. Radioactivity of ¹³¹I-chTNT after intravenous administration was mainly concentrated in the lung and liver, least in the brain. Radioactivity of tumor tissues reached the maximum at 24 h and the tumor/normal tissue (T/N) ratio reached the maximum (1.28~3.83) during 3~7 d. The characteristics of in vivo biological distribution of ¹³¹I-chTNT in patients with pulmonary metastases from differentiated thyroid carcinoma are favorable for its therapeutic application for the metastasis tumors.

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Due to their low cost, flexibility, and convenience for long distance data transfer, plastic scintillation fibers (PSF) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this paper, GEANT4 Monte Carlo simulation tool was used to obtain some radiation effects of PSF under high-energy neutron irradiation. BCF-20, a plastic fiber material, produced by Saint-Gobain, was used in the simulation. The fiber consists of a core scintillating material of polystyrene and an acrylic outer cladding. Incident neutrons produce energy deposition in fiber through neutron induced recoil proton events. The relationships between energy deposition efficiency and fiber length, fiber radius and incident neutron energy are presented. The variation with those parameters and parameter selection are also analyzed.

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The fragmentation process of high-temperature molten drop is a key factor to determine the ratio heat transferred to power in FCIs, which estimates the possible damage degree during the hypothetical severe accident in the nuclear reactors. In this paper, the fragmentation process of melt droplet in FCIs is investigated by theoretic analysis. The fragmentation mechanism is studied when an external pressure pulse applied to a melt droplet, which is surrounded by vapor film. The vapor film collapse which induces fragmentation of melt droplet is analyzed and modeled. And then the generated pressure is calculated. The vapor film collapse model is introduced to fragmentation correlation, and the predicted fragment size is calculated and compared with experimental data. The result shows that the developed model can predict the diameter of fragments and can be used to calculate the fragmentation process appreciatively.

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Reliability allocation is a difficult multi-objective optimization problem. This paper presents a methodology for reliability allocation that can be applied to determine the reliability characteristics of reactor systems or subsystems. The dualistic contrast, known as one of the most powerful tools for optimization problems, is applied to the reliability allocation model of a typical system in this article. And the fault tree analysis, deemed to be one of the effective methods of reliability analysis, is also adopted. Thus a failure rate allocation model based on the fault tree analysis and dualistic contrast is achieved. An application on the emergency diesel generator in the nuclear power plant is given to illustrate the proposed method.

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