实施研究生弹性学制改革是高校提升人才培养质量,加快“双一流”建设的重要着力点.我国研究生弹性学制改革经历三个阶段,形成四种弹性学制实践模式,未来应从扩大办学自主、拓宽招生范围,加强贯通分流、破解衔接障碍,优化资源投入、健全保障机制等方面入手,拓展弹性学制实践路径.

研究生教育是高层次创新型人才培养水平和科技创新潜力的重要标志,对提高国家科技实力、综合国力和全球竞争力具有重要意义.以过程管理理论和多中心治理理论为基础,从院校管理、导师响应、个体调节和培养质量四个维度设计基于满意度的研究生培养质量调查问卷.对问卷数据进行多层线性模型分析发现,教育资源、科研实践、导学关系等对研究生的培养质量有着显著的正向关系.针对影响研究生培养质量的各相关因素,研究从瞄准科研训练"靶心"、激发导师"掌舵者"作用;加大资源投入的"保障之网";共同发挥政府和高校"两只手"作用等方面提出了进一步推进研究生教育综合改革、提升研究生培养质量的对策建议.

新中国成立以来,我国研究生教育学制经历了多次变革.国际接轨需要、国家政策支持、经济社会推动、高校竞争发展、导学关系冲突等是触发研究生学制变革的主因,社会对不同层次人才的需求是研究生学制变革所遵循的逻辑,重视培养环节、尊重学校办学自主权是研究生学制变革的主要特点.现阶段我国研究生学制仍存在不同类型、层次及专业的学制趋同化和人才培养质量与社会需求脱节等问题,为全面提升研究生教育质量,应在理清研究生学制与培养质量关系的基础上,明确研究生教育的定位及培养目标,注重不同学科专业的差异及培养规律,完善与学制相关的配套制度.

This paper through the questionnaire for the full-time master of engineering in a comprehensive university, this paper investigates the current cultivation of full-time master of engineering, such as enrollment motivation, curriculum de-sign, guidance of outside school tutor, practice teaching, thesis writing, etc. Meanwhile, it puts forward the corresponding countermeasures and suggestions.

A series of stable waterborne polysiloxaneurethane (WPSUR) dispersions were prepared using amino-terminated polydimethylsiloxane (NS), dimethylolpropionic acid (DMPA), castor oil, polypropylene glycol and toluene diisocyanate. Meanwhile, NS with different molecular weights was synthesized and used as the soft co-segment. Effects of types and contents of soft co-segments as well as chain extenders on the thermal degradation and stability for WPSUR films were examined. Results reveal that WPSUR films exhibit excellent water resistance and mechanical properties as compared with pure polyurethane (PU) films, and the NS soft co-segment possesses a remarkable effect on the second stage (stage II), while the content of the hard segment is propitious to the initial stage (stage I). Moreover, the highest temperature of stage II (T 2m) for WPSUR films using NS as soft co-segment is 413°C, approximately being 30°C higher than that of those typical PUs using HDA and APDMS as the chain extenders, respectively.

A novel nanocomposite aqueous dispersion composed of waterborne polysiloxane-urethane/montmorillonite(WPSUR/MMT) was synthesized by self-made amino-terminated polydimethylsiloxane(NS) as chain extender.Wide angle X-ray diffraction(WXRD) and transmission electron microscopy(TEM) showed that MMT's ordered structure was destroyed after its intercalation with polyether,and random strips were scattered in WPSUR.Therefore,stripped type WPSUR/MMT nanocomposites were obtained.The experimental results showed that with the increase of the amount of MMT,the particle size of aqueous dispersion increased,apparent viscosity increased.With the same amount of MMT,the particle size of aqueous dispersion with NS as chain extender is lager than that with micromolecule as chain extender,its apparent viscosity is high.The introduction of MMT significantly improved the mechanical properties of WPSUR/MMT film.When the mass fraction of MMT was 1 %,the tensile strength and elongation at break of WPSUR/MMT film increased 22.8% and 9.6% compared to blank WPSUR,reinforcing and toughening the WPSUR.Both NS and MMT improved the heat resistance of WPSUR film when NS was used as chain extender.The weight loss peak temperature in the second phase of WPSUR/MMT(3%) film increased by 20℃.

Aqueous polysiloxane-polyurethane block copolymer was synthesized by two-step method,and the influence of the siloxane content in the block copolymer on mechanical properties,thermal properties,hardness,and surface contact angle was also studied.It is found that,as the siloxane content in the copolymer increases,the tensile strength and the modulus increases,while elongation at break decreases first and then increases.The thermal stability is also enhanced with the addition of polysiloxane segment.The surface contact angle increases with the increase of the siloxane content,which results in good water resistance for the system.

The waterborne siloxane-polyacrylate dispersion was synthesized using self-made vinyl-capped siloxane oligomer (NS),methyl methacrylate (MMA),butyl acrylate (BA) by means of emulsion polymerization. The influence of the different monomers ratio on the properties of the emulsion and film was studied. Particle size,morphology of particles,water resistance,and mechanical properties of the films were also examined. It is found that the diameter of the latex particle is 30 nm～ 60 nm and the film obtained appears very transparent,smooth and good mechanical properties. Moreover,when the silicone content is 10%,the contact angle of the film is over 100°,almost as the same as that of the pure polysiloxane. This can be ascribed to the addition of the vinyl-capped siloxane oligomer.

A series of waterborne polyurethane dispersions (PUDs) were synthesized using castor oil, polypropylene glycol, toluene diisocyanate, and (2E)-4-(2,3-dihydroxypropoxy)-4-oxobut-2-enoic acid [glycol semi-ester (GSE)]. These PUDs can be crosslinked spontaneously upon drying, without extra additives or processing steps. Moreover, the rheological properties, particle size, and morphology of PUDs were examined with stress-controlled rheometer, light scattering ultrafine particle analyzer, and transmission electron microscopy. Results reveal that the particle size of PUDs mainly depends on the concentrations of castor oil, GSE, and polymer. With the increase of GSE concentration and the decrease of castor oil and polymer concentration, the particle size decreases. This can be ascribed to the decrease of the particle size of the polymer dispersion, because of the decrease of the relative size of water layer to total particle size. Furthermore, increased amount of castor oil, GSE, and polymer concentrations results in an increased viscosity of PUDs because of the increase of effective volume for the dispersed phase. POLYM. ENG. SCI., 49:162-167, 2009. (C) 2008 Society of Plastics Engineers