In this study,transparent K_(2)O-Al_(2)O_(3)-SiO_(2)(KAS)glass-ceramics with leucite as the main crystalline phase were prepared by melting-quench method and two-step heat treatment.The effects of SiO_(2)/Al_(2)O_(3) ...In this study,transparent K_(2)O-Al_(2)O_(3)-SiO_(2)(KAS)glass-ceramics with leucite as the main crystalline phase were prepared by melting-quench method and two-step heat treatment.The effects of SiO_(2)/Al_(2)O_(3) ratio and heat treatment on crystallization and mechanical properties were studied.The crystallization kinetics and X-Ray Diffraction(XRD)results showed that SiO_(2)/Al_(2)O_(3) ratio and heat treatment system had a direct impact on the crystallization behavior of potassium aluminosilicate glass-ceramics.When heat-treated at 680℃/2 h and 780℃/1 h,cracks generated on the surface of the sample with the addition of SiO_(2)/Al_(2)O_(3)=4.8(in mol)due to the huge difference in the coefficient of thermal expansion between glass matrix and surface.When the addition of SiO_(2)/Al_(2)O_(3)(in mol)was 4,the sample with leucite as the main crystalline phase showed an excellent fracture toughness(1.46 MPa·m^(0.5))after the heat treatment of 680℃/2 h and 780℃/5 h.And there was a phase transformation from kaliophilite to leucite.The crystalline phases of the sample heat-treated at 680℃/8 h and 780℃/1 h were leucite and kaliophilite,which resulted in the visible light transmittance of 63%and the fracture toughness of 0.91 MPa·m^(0.5).Furthermore,after the heat treatment of 680℃/2 h and 780℃/5 h,the main crystalline phase of the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol)was still kaliophilite.Because leucite only grows on the surface of the sample and is hard to grow inward,it is hard to achieve the bulk crystallization of leucite in the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol).展开更多
The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,t...The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,transverse and longitudinal velocity distribution of the glasses with different compositions were studied.Furthermore,the influence of these factors on the width and thickness of the flexible glass plate was investigated.It is found that the internal and external heat exchange of glass has a dominant influence on the viscosity variation during the UTG forming process,which is inconsistent with the general viscosity-temperature dependence.The glass that first reaches the lower limit of forming viscosity can significantly resist the shrinking effect caused by surface tension,making the glass wider during the forming.If the original glass width remains unchanged,the glass thickness or feeding speed is reduced,wider and thinner flexible glasses can be produced.展开更多
目的评价Y型双支架取栓治疗急性大脑中动脉(MCA)M1段分叉部闭塞脑梗死的有效性、安全性和预后。方法回顾性分析2017年5月至2020年9月厦门大学附属中山医院采用Y型双支架取栓治疗的连续7例急性MCA-M1段分叉部闭塞脑梗死患者临床资料。采...目的评价Y型双支架取栓治疗急性大脑中动脉(MCA)M1段分叉部闭塞脑梗死的有效性、安全性和预后。方法回顾性分析2017年5月至2020年9月厦门大学附属中山医院采用Y型双支架取栓治疗的连续7例急性MCA-M1段分叉部闭塞脑梗死患者临床资料。采用改良溶栓治疗脑梗死(m TICI)血流分级评估术后血管再通情况,改良Rankin量表(mRS)评分评定术后90 d临床预后。结果6例患者经多次单支架取栓血管均未通,遂以Y型双支架取栓均1次再通,其中5例mTICI血流分级为3级,1例为2b级;1例直接双支架取栓1次再通,mTICI血流分级为3级。5例患者(5/7)术后90 d m RS评分为1~3分,2例死亡。结论采用Y型双支架取栓治疗急性MCA-M1段分叉部闭塞脑梗死1次再通率高,可缩短取栓时间,预后较好。展开更多
Aluminum sol,dry gel,and film were prepared by sol-gel and a dipping-withdrawing method.The effect of polyethylene glycol(PEG)on the behavior of aluminum sol,gel,and film was investigated by DLS,rotary viscometer,XRD,...Aluminum sol,dry gel,and film were prepared by sol-gel and a dipping-withdrawing method.The effect of polyethylene glycol(PEG)on the behavior of aluminum sol,gel,and film was investigated by DLS,rotary viscometer,XRD,IR,EPMA,and light microscope,respectively.The solid gels drying at room temperature was identified as amorphous phase,and the addition of PEG nearly has no effect on the structure of aluminum dry gel.It is indicated that the sol viscosity decreases with the PEG content increasing,while the micelle size in sol decreases first then increases.The uniformity and attached particles of the film are improved to a certain extent after PEG addition.According to the analytic results,we demonstrate that the improvement is caused by low viscosity and small micelle size of sol resulting from the PEG addition.展开更多
基金Funded by State Key Laboratory of Silicate Materials for Ar-chitectures(Wuhan University of Technology)(No.2011DA105356)。
文摘In this study,transparent K_(2)O-Al_(2)O_(3)-SiO_(2)(KAS)glass-ceramics with leucite as the main crystalline phase were prepared by melting-quench method and two-step heat treatment.The effects of SiO_(2)/Al_(2)O_(3) ratio and heat treatment on crystallization and mechanical properties were studied.The crystallization kinetics and X-Ray Diffraction(XRD)results showed that SiO_(2)/Al_(2)O_(3) ratio and heat treatment system had a direct impact on the crystallization behavior of potassium aluminosilicate glass-ceramics.When heat-treated at 680℃/2 h and 780℃/1 h,cracks generated on the surface of the sample with the addition of SiO_(2)/Al_(2)O_(3)=4.8(in mol)due to the huge difference in the coefficient of thermal expansion between glass matrix and surface.When the addition of SiO_(2)/Al_(2)O_(3)(in mol)was 4,the sample with leucite as the main crystalline phase showed an excellent fracture toughness(1.46 MPa·m^(0.5))after the heat treatment of 680℃/2 h and 780℃/5 h.And there was a phase transformation from kaliophilite to leucite.The crystalline phases of the sample heat-treated at 680℃/8 h and 780℃/1 h were leucite and kaliophilite,which resulted in the visible light transmittance of 63%and the fracture toughness of 0.91 MPa·m^(0.5).Furthermore,after the heat treatment of 680℃/2 h and 780℃/5 h,the main crystalline phase of the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol)was still kaliophilite.Because leucite only grows on the surface of the sample and is hard to grow inward,it is hard to achieve the bulk crystallization of leucite in the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol).
基金the National Key Research and Development Program of China(No.2022YFB3603300)。
文摘The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,transverse and longitudinal velocity distribution of the glasses with different compositions were studied.Furthermore,the influence of these factors on the width and thickness of the flexible glass plate was investigated.It is found that the internal and external heat exchange of glass has a dominant influence on the viscosity variation during the UTG forming process,which is inconsistent with the general viscosity-temperature dependence.The glass that first reaches the lower limit of forming viscosity can significantly resist the shrinking effect caused by surface tension,making the glass wider during the forming.If the original glass width remains unchanged,the glass thickness or feeding speed is reduced,wider and thinner flexible glasses can be produced.
文摘目的评价Y型双支架取栓治疗急性大脑中动脉(MCA)M1段分叉部闭塞脑梗死的有效性、安全性和预后。方法回顾性分析2017年5月至2020年9月厦门大学附属中山医院采用Y型双支架取栓治疗的连续7例急性MCA-M1段分叉部闭塞脑梗死患者临床资料。采用改良溶栓治疗脑梗死(m TICI)血流分级评估术后血管再通情况,改良Rankin量表(mRS)评分评定术后90 d临床预后。结果6例患者经多次单支架取栓血管均未通,遂以Y型双支架取栓均1次再通,其中5例mTICI血流分级为3级,1例为2b级;1例直接双支架取栓1次再通,mTICI血流分级为3级。5例患者(5/7)术后90 d m RS评分为1~3分,2例死亡。结论采用Y型双支架取栓治疗急性MCA-M1段分叉部闭塞脑梗死1次再通率高,可缩短取栓时间,预后较好。
基金Funded by the Fundamental Research Funds for the Central Universities(WUT:2020Ⅲ017GX)the National Key Research and Development Program of China(No.2016YFB0303700)。
文摘Aluminum sol,dry gel,and film were prepared by sol-gel and a dipping-withdrawing method.The effect of polyethylene glycol(PEG)on the behavior of aluminum sol,gel,and film was investigated by DLS,rotary viscometer,XRD,IR,EPMA,and light microscope,respectively.The solid gels drying at room temperature was identified as amorphous phase,and the addition of PEG nearly has no effect on the structure of aluminum dry gel.It is indicated that the sol viscosity decreases with the PEG content increasing,while the micelle size in sol decreases first then increases.The uniformity and attached particles of the film are improved to a certain extent after PEG addition.According to the analytic results,we demonstrate that the improvement is caused by low viscosity and small micelle size of sol resulting from the PEG addition.
