分类: 核科学技术 >> 核材料与工艺技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: As a potential matrix of three-dimensional gel dosimeter, agarose hydrogels will be used for measuring radiation doses, hence the importance of studying their radiation resistance and radiolysis mechanism. Physical property and chemical structure of physically cross-linked agarose hydrogel samples irradiated to 0200 kGy by 60Co -rays were analyzed by universal testing machine, gel permeation chromatography, fourier transform infrared spectrometer, ultraviolet visible spectroscopy, nuclear magnetic resonance, and gas chromatography. The results showed that agarose hydrogels had good radiation stability below 25 kGy, and the maximum compression strength of sample was ca. 0.1 MPa at 25 kGy. The irradiated samples degraded obviously and liquefied gradually with increasing doses. Compared with unirradiated sample, carbonyl groups, which generated from the molecular chains of agarose hydrogels, were observed at 25 kGy and increased gradually with dose. The main gas products evolved from irradiated agarose hydrogels were H2, CO2, CO and CH4. Based on the analysis of radiolytic products, the radiolysis mechanism of agarose hydrogels under -radiation was proposed.
分类: 核科学技术 >> 核材料与工艺技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The gel dosimeter has the uniquely capacity in recording radiation dose distribution in three dimensions (3D), which has the specific advantages in dosimetry measurements where steep dose gradients exist. In this study, a novel radiochromic gel dosimeter was developed by dispersing nanovesicles self-assembled by 10, 12-pentacosadiynoic acid (PCDA) into the tissue equivalence gel matrix. The characteristics of radiochromic PCDA vesicle gel dosimeters were evaluated. Results indicate that these radiochromic gel dosimeters have good linear response to 1.7 MeV electron beam irradiation in the dose range of 0.326.36 kGy. In addition, the radiochromic gel dosimeters overcome the limitations of the existing gel dosimeters such as diffusion effect, post-radiation effect, and poor forming ability. Hence, the radiochromic PCDA vesicle gel dosimeters developed could be generally applied to 3D dose distribution measurement with optical readout.
分类: 天文学 >> 天文学 提交时间: 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要: We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n 2σ) mean of specific star formation rate (sSFR) enhancement (sSFRenh = 0.33 ± 0.07 versus sSFRenh = 0.12 ± 0.06) and broader scatter (by ∼1 dex). The eight SFGs that have the highest sSFRenh in the sample all have pseudobulges. A majority (69%) of paired SFGs with strong enhancement (having sSFR more than 5 times the median of the control galaxies) have pseudobulges. The Spitzer data show that the pseudobulges in these galaxies are tightly linked to nuclear/circum-nuclear starbursts. Pseudobulge SFGs in S+S and in S+E pairs have significantly (>3σ) different sSFR enhancement, with the means of sSFRenh = 0.45 ± 0.08 and −0.04 ± 0.11, respectively. We find a decrease in the sSFR enhancements with the density of the environment for SFGs with pseudobulges. Since a high fraction (5/11) of pseudobulge SFGs in S+E pairs are in rich groups/clusters (local density N1Mpc ≥ 7), the dense environment might be the cause for their low sSFRenh.
提交时间: 2017-05-02
摘要: Various low ratios of triplet iridium complexes [0, 0.5, 1, 1.5, 2.5, and 5 mol%] are conjugated to the backbone of the famous champion donor polymer PTB7. At the same conditions, the power conversion efficiency for polymer containing 1% of Ir increases b
提交时间: 2017-05-02
摘要: Nanostructures of stereocomplex polylactide [sc-PLA] are obtained and studied in poly[l-lactide] [PLLA] doped with a low amount of poly[d-lactide] [PDLA] during successive melt-quenching, extrusion, spinning, and drawing processes corresponding to quiesce
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: In this paper, we present a systematic investigation on the shape memory/change effect in a double network nanocomposite tough hydrogel. Water-content dependency of the response of this hydrogel to heating and wetting by water is confirmed. Since this hydrogel is tough (even after being fully wetted in water) and has a relatively lower swelling ratio, apart from conventional shape memory/change effect as in ordinary hydrogels, additional features have been realized. These features include heating induced shape memory effect utilizing the absorbed water as the transition component, mechano-responsive shape change effect after water wetting and water-induced shape memory effect.