最新刊期
期 2 ， 1996
- 摘要：Radiation processing has been a rapidly expanding technology in China since 1970s. About 50 facilities of 60Co source with the designed capacity more than 3.7 PBq have been set up in Beijing, Shanghai, and others 36 cities. The total charged activity of sources was more than 862 PBq.More than 26 electron beam （EB） irradiation facilities have been established. The total power of electron beams reached about 926 kW. The effectiveness of the process depends on the proper application of dose and its measurement. The importance of dosimetry events on the processing control of irradiation technology and the quality assurance of irradiated products have been acknowledged in China, which are introduced in this paper.关键词：Dosimetry;Verification regulations;Plastic dosifilms;National standards;Traceability
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发布时间：2023-04-26 - 摘要：The mechanical properties and γ-radiation effects of blended NR/BR/HDPE have been studied. It was found that the presence of HDPE in the NR/BR/HDPE blend modified its thermo-plastielastomer properties and radiation induced cross-linking was produced in the blended polymer structure.关键词：Natural rubber;Butadiene rubber;High density polyethylene;Mechanical properties;Radiation effects;Blend
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发布时间：2023-04-26 - 摘要：CPE,DBDPO and Sb2O3 were used as flame-retardant of PE foam. Effect of CPE on PE foam under radiation and it's flame- retardancy were studied. The result showed that CPE can enhance radiation cross-linking of PE, and trinary of addition being made of CPE, DBDPO and Sb2O3 made oxygen index of PE foam achieveover 30, and self-extinguish, it didn't influence manufacture and mechanical properties of PE foam.关键词：Radiation cross-linking;PE foam;Flame retardency
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发布时间：2023-04-26 - 摘要：Structures and properties of the gamma-radiation induced graft coplymerization of acrylic acid (AA) to oriented polytetraf1uoroethylene (PTFE)were investigated with electron-optical microscope and X-ray diffraction. When AA is grafted onto oriented PTFE the birefringence (Δn) is found to be greater than that of the initial oriented specimen. It has been suggested that the grafting takes place in the submicro voids formed during the cold drawing of the PTFE. For a grafted AA content exceeding 75% violation of the chain orientation in the PTFE takes place owing to filling in all the submicro voids with the grafted polymer, affecting the dependence of Δn on the amount of the grafted AA. The structures and properties of absorbent water of the grafted copolymer was also discussed.关键词：Polytetrafluoroethylene;Orientation;Gamma-radiation;Structure;Property
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发布时间：2023-04-26 - 摘要：A new tow source positions irradiation method is reported. It is distinguished of that two source positions (one is lower and another is higher) are used to irradiate materials instead of one source position irradiation. Direction of the pile is 180° changed when it has been irradiated for half dose. This method can improve the radiation uniformity.It is holpful to use manpower and time sparely.关键词：Radiation;Radiation doses;Uniformity;Irradiation devices
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发布时间：2023-04-26 - 摘要：The effects of the post-radiation and the metal ion have been studied on the grafting reaction of methyl methacrylate onto light MgO with the mutual radiation method of election beam. The results showed that the post-radiation effect is that long-lived radical or ion in the grafting link continued polymerization off radiation field and Cu2+ in non water system might inhibite homopolymer.关键词：Magnesium oxide;Methyl methacrylate;Radiation grafting;Post-radiation effect;Metal ion effect
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发布时间：2023-04-26 - 摘要：The roles and characteristics of DNA polymerase β of hepatoma cells in participating in DNA repair synthesis induced by 60Co γ-rays irradiation were studied. Transplanted SMMC-LTNM hepatoma in mice was used as a tumor cells model. NEM and d2TTP were used as selective inhibitors to DNA polymerase α and β respectively. It was showed that the polymerase β could take part in repair synthesis of DNA damaged by γ-rays. The increment of 3H-TTP incorporation into DNA of SMMC-LTNM hepatoma cells nuclei was higher than that of normal hepatocyte nuclei (P<0.01). The DNA repair synthesis induced by DNA polymerase β reacted more fast in hepatoma cells nuclei than in hepatocytes nuclei too. These results indicated that the DNA repair synthesis of polymerase β in some tumor cells might be stronger than normal cells.关键词：DNA polymerase β;DNA repair;SMMC-LTNM hepatoma;γ-radiation
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发布时间：2023-04-26 - 摘要：After whole body exposed to 7.5 cGy X-ray, the C57 BL/6 mice were I. V. injected with 125IUdR labelled B16 melanoma cells, the proportion of surviving labelled cells retained in lungs was detected at 24 hours after injection,and found that the surviving cells in the lungs of irradiated mice were significantly decreased. Meanwhile, the immunofunctions were tested at 24 hours after irradiation, the results showed that the number of nucleate cells and NK cytotoxity in spleens, and the phagocytotic function of macrophages in vivo were increased obviously for the irradiated mice. The results suggested that the enhancement of NK cytotoxity and macrophage phagocytotic function might be one of the important reasons for low dose radiation accelerating the clearance of tumor cells from the lungs.关键词：Low dose radiation;B16 melanoma cells;Lungs;Immunofunctions
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发布时间：2023-04-26 - 摘要：The kinetics of chromosome damage and repair was determined by PCC. Chromosome damage repair was not detectable until 30 min after irradiation and nearly half of chromosome damage was repaired by 6 h. In contrast, significant DNA repair occured at 5 min after γ-irradiation measured by FADU technique. These results suggest that the early repairing DNA SSBs are not important in the formation of chromosome aberration, the different repair kinetics between DNA and chromosome damages might reflect their different repair mechanism.关键词：Chromosome darage and repair;PCC and FADU;DNA damage and repair
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发布时间：2023-04-26 - 摘要：Kunming male mice were irradiated by 0.05 Gy X-rays as the adaptive irradiation dose, then were exposed to 0.75~3.75Gy X-rays as the challenging irradiation doses. The chromosome aberrations in spermatogonia and spermatocytes and translocations in stem cells were observed. The results showed that the adaptive response appeared from 0.75~3.00Gy in all three kinds of cell, but the adaptive response was not obvious when the dose was 3.75 Gy. Those results indicated the challenging doses of irradiation had the adaptive response within limits.关键词：Challenging dose radiation;Germ cell;Chromosome aberration;Adaptive response
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发布时间：2023-04-26 - 摘要：Time courses and dose responses of γ-induced programmed cell death (PCD) in murine thymocytes after in vivo irradiation were studied, two methods (analysis of DNA fragmentation and flow cytometry) to determine PCD were implemented. The radiation sensitivity of different tissues was compared. It could be observed that the peak incidence of PCD occurred in thymocytes 4~6 h after irradiation. On the basis of this result, 6 h after irradiation was chosen for the determination of the dose response. The dose responses for thymocytes reached a plateau after dose of 20 Gy. Spleen and thymus, the radiosensitive organs, after 1 Gy γ-irradiatiom PCD could be detected,while the heart, brain and kidney, the non radiosensitive organs, PCD could only be detected after doses of 10 Gy and above.关键词：Programmed cell death;Radiation;Time and dose effect;Sensitivity of radiation
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发布时间：2023-04-26 - 摘要：Transforming growth factor β 3 (TGF β 3) is a multifunctional regulator of cell growth. In epithelial tissue TGF β 3 was found to be a negative regulator of growth, it inhibits the proliferation in the small intestinal crypts of the mouse following in vivo administration. Various doses and dosing regimens were tested, TGF β 3 was an effective inhibitor of proliferation in unirradiated and after irradiated 18 hours recipients in all multiple doses cases, TGF β 3 tended to have its strongest inhibitory effects in the lower regions of the crypt.关键词：Intestinal crypt;Cell proliferation;TGF β 3
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发布时间：2023-04-26 - 摘要：The chromosomal aberrations of germ cells were increased with total exposure dosage 0~2.1 Gy after chronical 60Co radiation.But the chromosomal aberrations of bone marrow cells was irragular with the same exposure dosage. The chromosomal aberration rate of bone marrow cells was larger than that of germ cells. The rate of chromosomal translocation in germ cells was 2.6 times larger than that in bone marrow cells 40 days after irradiation. This result was similar with acute exposure.关键词：Mice germ cells;60Co γ-ray chronic exposure;Bone marrow cells;Chromosome aberration
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发布时间：2023-04-26 - 摘要：The effects of 248 nm laser light on alkaline solutions of guanine(Gua), guanosine(Guo), 2′-deoxyguanosine-5′-monophosphoric acid (dGMP), poly-guanylic acid(5′) (poly[G]) and single-stranded DNA (ssDNA) were investigated, and monophotonic ionization was demonstrated. Based on pH titration, it was confirmed that the photoionization occurs on a deprotonated Gua moiety of DNA. The quantum yield of photoelectron (ϕe-)was measured.关键词：Guanine derivative;DNA;Photoionization;Monophotonic process;Quantum yield
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发布时间：2023-04-26
- 摘要：A leuco dye film dosimeter for dose measurement on 60Co gamma radiation processing was developed. The matrix material polyvinyl butyral （PVB） with leuco malachite green （LMG） and additive halogenated compounds （RX） were manufactured as the PVG dosifilm. Its response （ΔA/L vs dose） at 627 nm showed a linearity （correlation coefficient r> 0.999） in the dose range from 0.5 to 80 kGy. The calibration coefficient of temperature during irradiation was+0.053/℃. The response increased slightly with the increasing of relative humidities （0~96.4%）; and the the calibration coefficient was +0.006/Δ r. h （%）. From 54.9% to 96.4% the deviation was less than 4%. The PVG dosifilm was stable before and after irradiation when it was stored in the dark at a given relative humidity. The deviation of response on PVG dosifilm kept in a brown desiccator was less than 4% after 40 days. It was suitable to serve as a routine dosimeter.关键词：Polyvinyl butyral;Leuco malachite green;Halogenated organic compounds;Radiochromic film dosimeter;Radiation processing
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发布时间：2023-04-26
研究论文
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