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Hou X.P.,Beijing Radiation Application Research Center | Li S.F.,Beijing FD Science and Technology Co | Chen Y.,Beijing FD Science and Technology Co | Xu D.,Beijing FD Science and Technology Co | Tang W.,Beijing FD Science and Technology Co
Materials Science Forum

We develop an ultra-thin, highly filled, neutron-shielding material. This material exhibits a desirable neutron-shielding performance, and also has certain advantageous mechanical properties and uses. We study the physical properties of shielding materials with different polyolefins as base materials, and investigate the neutron-shielding performance of boron-containing and lithium-containing shielding materials. We furthermore report on the effect of additive amounts of functional additives on shielding properties and physical-chemical properties. We additionally study the effect of radiation crosslinking technology on shielding material properties. We show that, using ethylene-octene copolymer (POE) modified low-density polyethylene (PE-LD), the additive amounts of boron carbide (B4C) and nano-montmorillonite (OMMT) are 60–70% and 4%, respectively. The optimal radiation dose is 160 kGy, and the shielding materials exhibit good neutron-shielding performance and mechanical strength. © (2015) Trans Tech Publications, Switzerland. Source

Meng X.-F.,Beijing Radiation Application Research Center | Zeng X.-M.,Beijing Radiation Application Research Center | Lin M.,China Institute of Atomic Energy
Yuanzineng Kexue Jishu/Atomic Energy Science and Technology

The Bragg peak indicates the energy deposition characteristics of the charged-particle in a medium. The energy contribution and the monochromaticity of the charged-particle beams can be determined by analyzing their distribution and sharpness. The article introduces the design principle, performance testing and pilot use of a multi-anode gas ionization chamber, which can detect the Bragg peak generated in free air quickly. The voltage-current characteristics, the measurement repeatability and stability were all measured in a 90Sr- 90Y β reference field. The primary experiment results indicate that the chamber has good saturation characteristic, repeatability and stability, and the measured range of α particle generated by 241Am source is well coincided with the simulated results made by SRIM code. Source

Liu J.-W.,Beijing Radiation Application Research Center | Guo Y.-Y.,Beijing Radiation Application Research Center | Jiao Y.,Beijing Radiation Application Research Center | Lu Y.-J.,Beijing Radiation Application Research Center
Yuanzineng Kexue Jishu/Atomic Energy Science and Technology

EPDM was procured by electron beam (EB) irradiation. The sensitizing efficiency of trimethylopropane trimethylacrylacrylate (TMPTMA) was studied. The compression set, water absorption, mechanical properties and surface of EPDM foam were compared at different absorbed doses. The results show that the closed cell property and mechanical properties of EPDM foam are heightened at 5-15 kGy. Source

Yu H.,Beihang University | Yu H.,Beijing Radiation Application Research Center | Zeng X.,Beijing Radiation Application Research Center | Xiang Y.,Beihang University | Zhao X.,Beihang University
Acta Polymerica Sinica

A proton exchange membrane ( PEM ) was produced by simultaneous radiation grafting of pstyryltrimethoxysilane ( StSi ) into polytetrafluoroethylene ( PTFE ) membranes, followed by sulfonation, hydrolyzation and condensation. The effects of solvent, absorbed dose, absorbed dose rate and monomer concentration on the degree of grafting (DOG) were studied. Toluene was chosen for its higher boiling point and giving a higher DOG with acceptable mechanical strength. DOG increased with increasing the absorbed dose and monomer concentration and changed little with the absorbed dose rate at 10-43 Gy·min -1. Monomer concentration of < 3 mol · L -1 was better for reducing the copolymer. The degree of sulfonation ( DOS ) was as high as 92% -97% at DOG > 23% , making the properties of the PEM rely much on the DOG. Scanning electron microscopy ( SEM ) gave imagines of radiation grafting happened through the surface to the centre of the membrane. The ion exchange capacity ( IEC) , water uptake, dimension expansion and proton conductivity grew up with the increase of DOG for more hydrophilic -SO 3H,-Si-O-Si- crosslinking structure, and Si-OH groups were incorporated in the PEM. In addition, proton conductivity got better with temperature increase due to the good water uptake. Most of the grafted membranes exhibited lower methanol permeability than Nafion®.The prepared PEM in this work showed a good combination of high IEC (1.53 mmol·g -1) , dimension stability (dimension changed less than Nafion®117 at 90°C ) ,acceptable water uptake ( <63% at 90°C) and proton conductivity (1.5 × 10 -2 S · cm -1 at 90° and DOG 72.5%), and low methanol permeability (0.82 × 10 -6cm 2·s -1 at DOG 50.1%). PTFE, Styryltrimethoxysilane, Radiation grafting, Proton exchange membrane. Source

Yu H.Y.,Beihang University | Wang L.C.,Beijing Radiation Application Research Center | Li Y.,Beihang University | Zeng X.M.,Beijing Radiation Application Research Center | Zhao X.Q.,Beihang University
Advanced Materials Research

To get bioorganic surface with improving biological properties, NiTi shape memory alloy was bonded poly (ethylene glycol) (PEG) by sequentially piranha solution treating, silanizing, and then γ-ray irradiation induced grafting. Piranha solution treating gave hydroxylated surfaces for the benefit of next silanization. The trichlorovinylsilane (TCVS) was performed as a bridge to covalent bond treated NiTi substrates and PEG by γ-irradiation. X-ray photoelectron spectroscopy (XPS) was used to indicate that PEG was bonded on silanized NiTi surface by irradiation. Osteoblast culture of 1 day and methyl-thiazol-tetrazolium (MTT) assay showed that PEG bonded on NiTi surface enhanced cell proliferation and cell amount increased significantly with increasing the concentration of bonded PEG. © (2013) Trans Tech Publications, Switzerland. Source

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