In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically studied.The focus is on the...In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically studied.The focus is on the optimal amount of rare earth oxides that can produce ideal results.Special attention was paid to their main strengthening mechanisms,including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase.Y_(2)O_(3),La_(2)O_(3) and CeO_(2) rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying elements.These advantages can significantly improve the mechanical properties of the alloy.Thereafter,this paper outlines the future research directions of rare earth oxides,aiming to expand their application potential.展开更多
Eight cases of brachial plexus nerve damage caused by overdose radiation from linear accelerator are reported. Hyperesthesia and sharp pain were the early clinical manifestations, subsequently the limbs were numb and ...Eight cases of brachial plexus nerve damage caused by overdose radiation from linear accelerator are reported. Hyperesthesia and sharp pain were the early clinical manifestations, subsequently the limbs were numb and disfunctional.The symptoms aggravated progressively in 3 years after the radiation.Three yearo later,the patients's conditions became stable and recovered partially.The degree ofdamage was related to the dosage of radiation. The changes of EMG included appearance of spontaneous potentials,average prolonged duration, increased polyphasic potentials, average low amplitude and peak voltage, simple and mixed patterns, electrical silence or few low amplitude motor unit potentials,while the MCV became slower or disap eared in some injured muscles. The changes of EMG and MCV were proved to be useful both in the assessment of the degree and site of the damage and in the prediction of the prognosis.展开更多
In this paper, poly（vinyl alcohol）（PVA） and PVA/poly（ethylene glycol）（PEG） hybrid hydrogels were synthesized by freeze-thawing or freeze-thawing followed by high energy electron beam irradiation. The influence...In this paper, poly（vinyl alcohol）（PVA） and PVA/poly（ethylene glycol）（PEG） hybrid hydrogels were synthesized by freeze-thawing or freeze-thawing followed by high energy electron beam irradiation. The influence of PEG molecular weight, mass ratios of PVA to PEG, thawing temperature and number of freeze-thawing（FT） cycles on the mechanical strength of PVA/PEG hydrogel was investigated. Also, the thermal behaviors were examined by differential scanning calorimetry（DSC） and the microstructttres were observed with scanning electron microscopy（SEM）. The results suggest that the addition of PEG improves the mechanical strength of PVA hydrogel and the irradiation reduces both the strength of PVA/PEG hydrogel slightly and the degree of crystallinity. The improved properties suggest that PVA/PEG hydrogel can be a good candidate for the application in the biomedical.展开更多
基金Project supported by China Postdoctoral Science Foundation(2021M7010380)the Natural Science Foundation of Shanghai (20ZR1422700)Class Ⅲ Peak Discipline of Shanghai-Materials Science and Engineering (High-Energy Beam Intelligent Processing and Green Manufacturing)。
文摘In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically studied.The focus is on the optimal amount of rare earth oxides that can produce ideal results.Special attention was paid to their main strengthening mechanisms,including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase.Y_(2)O_(3),La_(2)O_(3) and CeO_(2) rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying elements.These advantages can significantly improve the mechanical properties of the alloy.Thereafter,this paper outlines the future research directions of rare earth oxides,aiming to expand their application potential.
文摘Eight cases of brachial plexus nerve damage caused by overdose radiation from linear accelerator are reported. Hyperesthesia and sharp pain were the early clinical manifestations, subsequently the limbs were numb and disfunctional.The symptoms aggravated progressively in 3 years after the radiation.Three yearo later,the patients's conditions became stable and recovered partially.The degree ofdamage was related to the dosage of radiation. The changes of EMG included appearance of spontaneous potentials,average prolonged duration, increased polyphasic potentials, average low amplitude and peak voltage, simple and mixed patterns, electrical silence or few low amplitude motor unit potentials,while the MCV became slower or disap eared in some injured muscles. The changes of EMG and MCV were proved to be useful both in the assessment of the degree and site of the damage and in the prediction of the prognosis.
文摘In this paper, poly（vinyl alcohol）（PVA） and PVA/poly（ethylene glycol）（PEG） hybrid hydrogels were synthesized by freeze-thawing or freeze-thawing followed by high energy electron beam irradiation. The influence of PEG molecular weight, mass ratios of PVA to PEG, thawing temperature and number of freeze-thawing（FT） cycles on the mechanical strength of PVA/PEG hydrogel was investigated. Also, the thermal behaviors were examined by differential scanning calorimetry（DSC） and the microstructttres were observed with scanning electron microscopy（SEM）. The results suggest that the addition of PEG improves the mechanical strength of PVA hydrogel and the irradiation reduces both the strength of PVA/PEG hydrogel slightly and the degree of crystallinity. The improved properties suggest that PVA/PEG hydrogel can be a good candidate for the application in the biomedical.
