Loss of light yield of doped lead tungstate crystals after irradiation with a low dose rate has been observed.The La,Pr,and Y doping may improve radiation hardness,whereas Bi or Mo doping is harmful.
The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing ...The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing an 8% prepulse of 70ps before the main pulse,the fraction of high energy γ-ray photons(hv>l00keV)was significantly enhanced relative to low energy photons(hv<100 keV).展开更多
The cumulan t correlators and azimuthal correlations of particles produced in protonproton(PP)collisions at 400 GeV/c are investigated.The second-order cumulant correlators show that the two particle correlation lengt...The cumulan t correlators and azimuthal correlations of particles produced in protonproton(PP)collisions at 400 GeV/c are investigated.The second-order cumulant correlators show that the two particle correlation length may be determined by comparing the experimental data with the Monte Carlo events sample which has same multiplicity distributions but no correlation.The azimuthal correlation has also been observed.展开更多
背景:随着化学合成技术的发展,将抗骨质疏松药物纳入组织工程支架,用于促进骨质疏松性骨缺损骨再生已成为当今研究的热点。目的:介绍骨组织工程支架,讨论并总结其搭载抗骨质疏松药物在骨质疏松性骨缺损愈合方面的应用。方法:作者以"...背景:随着化学合成技术的发展,将抗骨质疏松药物纳入组织工程支架,用于促进骨质疏松性骨缺损骨再生已成为当今研究的热点。目的:介绍骨组织工程支架,讨论并总结其搭载抗骨质疏松药物在骨质疏松性骨缺损愈合方面的应用。方法:作者以"Osteoporosis,Bone defect,Scaffold,骨质疏松,骨缺损,支架"为关键词,检索2005至2017年期间Pub Med、Web of Science、Springerlink、Medline、万方、CNKI数据库中相关文献。初检文章201篇,筛选后对64篇文章进行分析。结果与结论:各种类型的骨组织工程支架被用于治疗骨质疏松性骨缺损,如经过改性的磷酸钙骨水泥、β-磷酸三钙、羟基磷灰石等支架均起到一定促进骨再生的作用。但骨质疏松状态下的骨再生受损严重,常规支架促进骨再生能力有限,需要加以抗骨质疏松治疗。考虑到全身抗骨质疏松药物治疗不良反应大、骨缺损局部作用小的特点,近年来研究者对支架植入与局部药物递送相结合促进骨质疏松性骨缺损愈合进行了研究,如何将骨再生诱导因子纳入支架中,并稳定地从支架中释放而不影响其生物活性是关键。其中,双膦酸盐、金属锶、骨形态发生蛋白2、甲状旁腺激素、中药成分、间充质干细胞作为常用药物,将其纳入凝胶中或通过涂层的方法与骨组织工程支架结合可达到缓释效果;随着分子生物技术的发展,经成骨相关基因修饰的干细胞复合支架也逐渐成为一个研究热点。展开更多
The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed pla...The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.展开更多
基金Supported by the Chinese Academy of Sciences under Grant No.006.
文摘Loss of light yield of doped lead tungstate crystals after irradiation with a low dose rate has been observed.The La,Pr,and Y doping may improve radiation hardness,whereas Bi or Mo doping is harmful.
基金Supported by the National Natural Science Foundation of China under Grant No.19854001the National High Technology ICF Committee under Grant No.416-3.
文摘The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing an 8% prepulse of 70ps before the main pulse,the fraction of high energy γ-ray photons(hv>l00keV)was significantly enhanced relative to low energy photons(hv<100 keV).
基金Supported by the National Natural Science Foundation of China.
文摘The cumulan t correlators and azimuthal correlations of particles produced in protonproton(PP)collisions at 400 GeV/c are investigated.The second-order cumulant correlators show that the two particle correlation length may be determined by comparing the experimental data with the Monte Carlo events sample which has same multiplicity distributions but no correlation.The azimuthal correlation has also been observed.
文摘背景:随着化学合成技术的发展,将抗骨质疏松药物纳入组织工程支架,用于促进骨质疏松性骨缺损骨再生已成为当今研究的热点。目的:介绍骨组织工程支架,讨论并总结其搭载抗骨质疏松药物在骨质疏松性骨缺损愈合方面的应用。方法:作者以"Osteoporosis,Bone defect,Scaffold,骨质疏松,骨缺损,支架"为关键词,检索2005至2017年期间Pub Med、Web of Science、Springerlink、Medline、万方、CNKI数据库中相关文献。初检文章201篇,筛选后对64篇文章进行分析。结果与结论:各种类型的骨组织工程支架被用于治疗骨质疏松性骨缺损,如经过改性的磷酸钙骨水泥、β-磷酸三钙、羟基磷灰石等支架均起到一定促进骨再生的作用。但骨质疏松状态下的骨再生受损严重,常规支架促进骨再生能力有限,需要加以抗骨质疏松治疗。考虑到全身抗骨质疏松药物治疗不良反应大、骨缺损局部作用小的特点,近年来研究者对支架植入与局部药物递送相结合促进骨质疏松性骨缺损愈合进行了研究,如何将骨再生诱导因子纳入支架中,并稳定地从支架中释放而不影响其生物活性是关键。其中,双膦酸盐、金属锶、骨形态发生蛋白2、甲状旁腺激素、中药成分、间充质干细胞作为常用药物,将其纳入凝胶中或通过涂层的方法与骨组织工程支架结合可达到缓释效果;随着分子生物技术的发展,经成骨相关基因修饰的干细胞复合支架也逐渐成为一个研究热点。
基金Supported by the National Natural Science Foundation of China under Grant Nos.19854001,10005014 and 19825110the National Hi-Tech ICF Programme。
文摘The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.
