Effect of Molecular Weight of PCL on the Structure and Mechanical Properties of PCL/PET Composite Vascular Scaffold Prototype

A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.     

关于硅薄膜液相外延中氧化问题的若干讨论

从热力学角度对ＬＰＥ中同时 Ｓｉ氧化与ＳｉＯ２腐蚀的动态平衡过程进行了分析,表明在Ｓｉ的低温同质液相外延中,一般的ＬＰＥ条件很难解决防止Ｓｉ的氧化问题。作者尝试采用饱和Ｓｎ源保护Ｓｉ衬底的方法来解决硅氧化问题,通过对外延层表面形貌和成分的分析研究,表明采用Ｓｎ源保护成功地解决了硅的氧化问题。     

Fabrication and Properties of Porous Film/Fabric Composites for Vascular Scaffold Application

A composite vascular scaffold combining textile reinforced structure and biodegradable polymer is introduced, which may possess high porosity and connectivity. Moreover, the porous size could be controlled. The proposed scaffold consists of a warp-knitted poly （ethylene terephthalate ） （PET） fabric with well-defined macropores, which is embedded with a porous biodegradable polymer membrane. The aim of this paper is to study the fabrication and properties of porous polymer membrane through optimizing the parameter of composite methods from freeze drying/particle leaching （ FD/PL ） and gas foaming/particle leaching （ GF/PL ）, subsequently combining with the warp-knitted fabric. Weighing method was utilized to analyze the porosity of the samples and the scanning electron microscope （SEM） images were taken to observe the porous structure of the vascular membrane. In addition, ,the static contact angle （CA） was measured to estimate the hydrophilicity of the samples, and the tensile testing of the composites was performed on the universal mechanical tester. Furthermore, the water permeability of the membrane was also calculated. The results showed that the porosity and pore connectivity of the vascular membrane were diverse, became of solution concentration, particle size, ratio of content, etc. Meanwhile, the stress-strain curves and the bursting strength showed the different mechanical properties among composite scaffolds in different structures.     

影响InGaP／InP半导体激光器阈值电流密度若干问题的研究

本文对影响ＩｎＧａＡｓＰ／ＩｎＰ激光器阈值电流密度的晶格失配，掩埋异质结构和掺杂控制等问题进行了分析和讨论．从Ｋｕｐｈａｌ和Ａｒａｉ模型着手计算了与ＩｎＰ晶格匹配ＩｎＧａＡｓＰ的熔体组成．并从实验上进行了仔细调整．获得了激射波长为１．３μｍ．失配量≤１．４×１０－３的ＤＨ结构ＬＰＥ工艺条件．探讨了新的腐蚀工艺和二次外延工艺参数对掩埋异质结构形成的影响；提出采用二次外延过程中Ｚｎ扩散来控制限制层（３）掺杂的新方法，避免了纵向ｐ－ｎ结偏位现象的出现．获得了室温下阈值电流最低小于２５ｍＡ、在６０ｍＡ直流驱动下单面光输出功率高达１２．５ｍＷ、激射波长为１．３μｍ的ＩｎＧａＡｓＰ／ＩｎＰＤＣ－ＰＢＨ激光器．