Characterization of mechanical properties and primary investigation of pyrolysis and sintering of polycarbosilane-derived continuous fibers

Hi-NicalonSiC纤维是通过先驱体法制备并已商品化的高性能连续纤维，是制备耐高温SiC/SiC复合材料的关键原材料。降低纤维中氧的含量可提高其高温使用性能，而降低纤维的直径、减少缺陷可提高其力学性能。本论文主要对Hi-NicalonSiC纤维的力学性能进行系统表征并对PCS制备连续SiC纤维的烧成工艺进行初步探索。对Hi-NicalonSiC纤维的研究结果表明：①纤维的强度服从Weibull分布；纤维的模量服从正态分布；纤维的应变服从正态分布；纤维的直径分布服从正态分布。②Hi-Nicalon纤维直径离散系数为8.9％；应变离散系数为15.8％；模量离散系数为10％；强度离散系数为14...Hi-Nicalon SiC fibers are commercial continuous high-performance fibers prepared by polymer precursor method. They are the critical materials to fabricate SiC/SiC composites with high temperature resistance. The fibers properties for high temperature will be increased with the oxygen contents reduced, and the mechanical properties can be also increased with diameters decreasing and the defects red...学位：工学硕士院系专业：化学化工学院_材料学学号：20023602

Study on preparation and in vitro release behavior of hydroxycamptothecin-loaded PLA microspheres

目的:研究载羟基喜树碱的聚乳酸微球的制备方法并考察其体外释药性质。方法:以PlA为成膜材料,采用改良乳化-溶剂挥发法,制备载羟基喜树碱的聚乳酸微球并优化制备工艺;对载药微球进行表征;超声介导下进行载药微球的体外释药试验。结果:微球粒径在1~7μM,大小均一;羟基喜树碱浓度在10Mg.Ml-1下,载药微球包封率为62.2%,载药量为1.69%;药物体外释药符合HIguCHI方程。结论:采用乳化-溶剂挥发法,以PlA为成膜材料可制得具有较高包封率的羟基喜树碱微球,有望实现降低羟基喜树碱给药量、减少不良反应,提高靶向性的目标。Objective:To prepare hydroxycamptothecin(HCPT)-loaded PLA microspheres and study the release of HCPT in vitro.Methods:To optimize the preparation process,the HCPT-loaded PLA microspheres were prepared by using an improved solvent evaporation method;drug-loaded microspheres was characterized;in vitro drug release experiments were carried out under ultrasound.Results:The sizes of drug loaded PLA microspheres were homogeneous and between 1--7 μm;the concentration of HCPT was 10 mg·mL-1,the drug encapsulation efficiency was 62.2%,and the drug-loading amounts was 1.69%;the release in vitro complied with Higuchi equation.Conclusion:The improved solvent evaporation method with PLA as the film-forming material can increase the encapsulation efficiency of HCPT-loaded microspheres,thus the reduction of dosage and improvement of toxic effects of HCPT would be expected.Targeting effect may be improved.福建省卫生厅青年科研项目(2009-2-79

FIBER-REINFORCED COPPER MATRIX COMPOSITES FABRICATED BY ELECTROCHEMICAL INFILTRATION TECHNIQUE

［中文文摘］基于电化学浸渗技术(ECI)在室温下制备了连续铜纤维、碳纤维和玻璃纤维增强铜基复合材料。实验结果表明,在本实验工艺条件下可获得致密的纤维/Cu基复合材料,并具有优良的力学性能。复合材料的断口形貌及显微结构的SEM观察表明,纤维与铜基体之间的界面结合良好,纤维不受任何损伤。证实了ECI在室温下快速制备纤维增强金属基复合材料的可行性。［英文文摘］Continuous-fiber-reinforced Cu matrix composites were fabricated based on the electrochemical infiltration technique (ECI). The experimental results show that the dense fiber/Cu composites have been obtained on the present condition, which possess good mechanical properties. The fracture surface morphology and microstructures of the composites have been observed by SEM. It is indicated that the interfacial bond between fibers and Cu matrix is very well and the fibers do not have any damage. The ECI is　feasible to prepare rapidly fiber reinforced metal matrix composites at room temperature

Pharmacokinetics of Dual Conjugated Chitosan-mitomycin C Nanoparticles in Rats

目的研究双修饰壳聚糖载丝裂霉素C纳米粒在大鼠体内的药动学特征。方法 2组大鼠分别静脉注射4 Mg·kg·1丝裂霉素C纳米粒和丝裂霉素C注射剂后,采用高效液相色谱-串联质谱法(HPlC-MS)测定给药后不同时间点血浆中丝裂霉素C的浓度,计算主要药动学参数。结果丝裂霉素C的线性范围20~1 000μg·l·1,最低定量限为20μg·l·1,提取回收率均>95%,日内、日间精密度rSd均<15%。双修饰壳聚糖载丝裂霉素C纳米粒和丝裂霉素C注射剂T1/2分别为(2.64±0.11)H、(0.49±0.049)H;AuC0-∞分别为(2.01±0.11)Mg·H·1·l·1、(0.93±0.075)Mg·H·1·l·1;Vz分别为(1.52±0.18)l、(0.63±0.065)l;Cl分别为(6.95±0.70)Ml·MIn·1、(15.47±1.89)Ml·MIn·1,2者均有显著性差异。结论该方法灵敏、准确、专一,适用于丝裂霉素C的药动学研究。与丝裂霉素C注射剂相比,双修饰壳聚糖载丝裂霉素C纳米粒具有缓释和长循环的作用。OBJECTIVE To study the pharmacokinetics of dual conjugated chitosan-mitomycin C nanoparticles(CS-MMC-NPs) in rats.METHODS The two groups of rats were injected with CS-MMC-NPs and MMC injection at the dose of 4 mg·kg·1.The concentrations of MMC in plasma at different time were determined by HPLC-MS and the main pharmacokinetic parameters were calculated.RESULTS The calibration curves were linear over the range of 20·1 000 μg·L·1.The limit of quantitation was 20 μg·L·1.The within day and day to day relative standard deviation(RSD) was <15%.The main pharmacokinetic parameters of CS-MMC-NPs and MMC injection were as follows: t1/2 were(2.64±0.11)h and(0.49±0.049)h, AUC0- ∞ were(2.01±0.11)mg·h·1·L·1 and(0.93±0.075)mg·h·1·L·1, Vz were(1.52±0.18)L and(0.63±0.065)L, CL were(6.95±0.70)mL·min·1 and(15.47±1.89)mL·min·1.The differences of parameters were significant between two preparations.CONCLUSION The method is sensitive, accurate, specific for the pharmacokinetic study of CS-MMC-NPs.Compared with MMC injection, CS-MMC-NPs has a controlled releasing rate, a high level of blood concentrations and a long blood circulation time, which benefits the control of acute toxicity of MMC for the rats.厦门市科学技术计划项目资助项目(3502Z20114007

Preparation and Characterization of Folic Acid and PEG Conjugated Chitosan Nanoparticles

目的利用离子交联和化学交联相结合的方法制备壳聚糖纳米粒子(nPS),并对nPS分别进行了叶酸(fA)和聚乙二醇(PEg)的修饰。方法通过红外光谱进行结构验证;用扫描电镜和粒度分析仪对粒子的微观形态、粒径、电位等进行了表征;通过与HElA细胞摄取实验对其靶向作用进行验证。结果离子交联和化学交联相结合的方法制备壳聚糖纳米粒子粒径在200 nM左右并且粒径分布窄,修饰后的nPS(fA-nPS、PEg-nPS及fA+PEg-nPS)粒径不受功能基团修饰的影响。激光共聚焦试验证明fA-nPS及fA+PEg-nPS能显著提高细胞对粒子的摄取,而PEg-nPS则明显降低其对粒子的摄取。结论 fA+PEg-nPS有望成为一种新型的药物载体,用于抗癌药物对癌细胞的主动靶向。OBJECTIVE An ionic gelation combined with chemical crosslinking method was developed to prepare chitosan nanoparticles,followed by conjugation with folate(FA) and polyethylene glycol(PEG).METHODS The structures were verified by infrared spectroscopy.The morphology,diameter and Zeta electric potential of the nanoparticles were assayed by environmental scanning electron microscope and scattering particle analyzer.The specificity of the FA+PEG-NPs targeting cancer cells was demonstrated by human adenocarcinoma Hela cells.RESULTS The chitosan NPs presented a narrow size distribution with an average diameter about 200 nm regardless of the type of functional group.Laser confocal scanning imaging proved that both FA+PEG-NPs and FA-NPs could greatly enhance uptake by Hela cells.However,the PEG-NPs showed contrary results.CONCLUSION FA+PEG-NPs can be applied as a new vehicle to actively deliver anticancer drugs to tumor cells.厦门市科学技术计划资助项目(3502Z20114007

In-Situ FTIR Spectroscopic Studies of Electro Oxidation of Ethanol in Alkaline Media at a nm-Pt/GC Electrode

运用电化学循环伏安和原位FTIR反射光谱研究了碱性介质中乙醇在nm Pt/GC电极上的氧化。结果表明 ,主要产物是CH3 COO-,仅存在少量乙醛 ,未检测到CO谱峰。与酸性介质中乙醇氧化的双途径机理不同 ,碱性介质中乙醇的氧化未经过解离吸附的中间步骤。The electro oxidation of ethanol on a nm Pt/GC electrode in alkaline solutions was investigated by using cyclic Voltammetry and in situ FTIR spectroscopy.The results demonstrated that the main product of ethanol oxidation was CH 3COO -,only small quantity of CH 3CHO was determined simultaneously.In contrast with the dual path reaction mechanism for the oxidation of ethanol in acid media,the oxidation of ethanol in alkaline media was revealed via the intermediate process of dissociative adsorption.国家自然科学基金项目!(2 98330 60 );; 国家教育部科学技术重点研究项目!(991 77)资

In-situ FTIR spectroscopic studies of electro oxidation of ethanol in alkaline media at a nm-Pt/GC electrode

The electro-oxidation of ethanol on a nm-Pt/GC electrode in alkaline solutions was investigated by using cyclic Voltammetry and in-situ FTIR spectroscopy. The results demonstrated that the main product of ethanol oxidation was CH3 COO-, only small quantity of CH3 CHO was determined simultaneously. In contrast with the dual path reaction mechanism for the oxidation of ethanol in acid media, the oxidation of ethanol in alkaline media was revealed via the intermediate process of dissociative adsorption

Deflection analysis of ligament between two fulcrums

分析了两种情况下的丝线的挠度 .一种是两个支点间丝线的直径是均匀的 ;另一种是丝线的直径是均匀变化的 .根据力学求解最大挠度的表达式 ,并讨论影响最大挠度的因素以及在实际 (特别是纤维的烧结和拉伸环节 )中的应用 .分析结果表明 :由于丝线长径比很大 ,丝线的最大挠度跟密度以及跨度的平方成正比 ,与所受的应力成反比 ,而同丝线的直径的具体数值和材料的刚度无关The deflection of filaments between two fulcrums was analyzed. Two kinds of filaments are (considered), one with uniform diameter and the other with a diameter gradient. The expressions of the (maximum) deflection were derived through mechanics analysis, and the parameters affecting the maximum (deflection) were discussed. The analysis indicates that the maximum deflection is directly proportional to density and the square of span, and inversely proportional to stress, but independent of diameter and elastic modulus

Investigated of Fiber-reinforced Metallic Matrix Composites Prepared by Electrochemical Method

［中文文摘］提出了利用电化学方法在室温下制备纤维增强金属基复合材料的新技术.详细阐述了制备工艺过程,并通过SEM观察了复合材料的断口形貌及显微结构.实验证实电化学浸渗技术具有在室温下快速制备纤维增强金属基复合材料的优点,导电或不导电纤维可用来作为增强剂.导电纤维可直接用于电化学浸渗,而不导电纤维在使用之前要进行表面金属化处理.初步实验结果表明,在5.5V和8h的沉积条件下可获得致密的纤维/铜基复合材料.［英文文摘］A novel technique of preparing fiberreinforced metallic matrix composites by electrochemical method was proposed. The processing procedures were described in details, and the fracture surface morphology and microstructure of the present composites have been observed by SEM. It is demonstrated that the electrochemical infiltration technique has obvious merits over the conventional processing techniques in the preparation of fiberreinforced metallic matrix composite. Either conductive or nonconductive　fibers may be used as reinforcing agents. Conductivefibers can be electrochemically infiltrated without additional treatment , while non2conductive fibers need to be surface2metallized before use. Preliminary experiments have shown that densefiber/copper matrixcomposites areobtainable at 5.5 Vfor 8 hfor the systems studied

Development of a droplet-interfaced high performance liquid chromatography-capillary electrophoresis two dimensional separation platform

蛋白质组体系的高度复杂性需要更高分辨率的多维分离技术。近年兴起的液滴技术在微纳尺度样品操控方面具有微体积、低扩散、无返混等独特优势,有望为多维分离平台的接口提供解决方案。通过采用不同结构的液滴微流控芯片可以实现“液滴生成“与“油相排除“功能,进行样品由连续流-非连续流-连续流的高效转移,将不同的分离模式进行二维耦联。本研究利用液滴作为接口技术耦联高效液相色谱与毛细管电泳构建二维分离系统,以蛋白质降解的复杂多肽混合物为样品,考察了液滴接口二维分离平台的可行性和有效性,并获得3 000以上的峰容量,初步展示了该接口技术在多维分离分析领域的应用潜力。Proteomics demands high resolution multidimensional separation techniques due to its extremely high complexity.Droplet microfluidics provides a series of unique advantages in manipulating micro and nanolitre samples,such as micro-volume operation,limited diffusion and none cross-contaminating,therefore has the potential to be an ideal interface strategy for multidimensional separation.Using the microchips of different structures,functions such as "droplet generation" and "oil depletion" can be realized.Based on these functions,samples can be transferred from continuous flow to segmented flow and then back to continuous flow.In this way,different separation modes can be combined.In this study,droplet technology was utilized as a novel interface strategy in combining high performance liquid chromatography(HPLC) and capillary electrophoresis(CE).Using tryptic peptides mixture as a sample,this two dimensional HPLC-CE system provided high resolution separation with a peak capacity over 3 000.This proof-of-principle study has demonstrated the usefulness of droplet interface technology in multidimensional separation.国家自然科学基金项目(No.21005065);教育部高等学校博士点专项科研基金项目(No.20100121120006