对中学物理教学方法的思考与探索

本文对物理教学中常见的三种课型--实验教学课、知识教学课和习题教学课的基本教学方法进行了分析,参照现代教学理论的新成果,兼收并蓄,设计了一种新的课堂教学模式--系统教学法.这种教学法,能有效地减轻学生的课业负担,全面提高物理教学质量.     

INFLUENCE OF POLYMER CHARACTERISTICS AND MELT-SPINNING CONDITIONS ON THE PRODUCTION OF HIGH RANDOMNESS 60PHB/PET THERMOTROPIC LIQUID CRYSTAL COPOLYESTER FIBER

Six samples of linear high randomness 60PHB/ PET thermotropic liquid crystal copolyesters are made by melt copolymerization at 290℃ , whose randomness about 0.955 is measured by the discernible 'H-NMR spectrometer. High tenacity, high module fiber is prepared by melt spinning in liquid crystal phase. The effect of molecular weight, shear rate, temperature as well as spinning drawn ratio on the mechanical behavior of 60PHB / PET copolyester fiber are shown that, lower shear rate (2~ 10 s~(-1)), higher temperature melting (300℃ ), lower temperature spinning (280℃ ) and higher molecular weight are favourable to the increase of the fiber mechanical properties. With the variance of drawn ratio, fiber mechanical property has a transition point due to traversion from shear-orientation to drawn-orientation. The copolyester fiber has high crystallinity, high orientation at the crystalline region, high chain orientation and high regular fibrillar structure.     

Liquid Flow in Shaped Fiber Bundle

By computation and comparison of the critical spreading coefficient parameter, it was found that shaped fiber bundle is better for wetting. Liquid-air interface tension of liquid arising the shaped fiber bundle body is considered as one critical factor besides liquid viscosity, inertia force and liquid-fiber interface tension. Experimental result simulation demonstrated that the liquid-air interface tension is correlated with the geometric size of the liquid arising in body, Φ0 （x） and which is affected by the cross sectional shape of fiber and the radius of single fiber. The shaped fiber bundle model is/ntroduced to/nvestigate liquid flow in fiber assembly. The model is generated based on a random function for stochastic forming of fibers in bundle and it is necessary to combine this fundamental model with physical explanation for investigation of liquid flow in fiber assembly.     

阻燃共聚酯固相缩聚反应结晶动力学研究

为了研究阻燃共聚酯(flame retardant co-polyesters,FRPET)固相缩聚(solid state polymerization,SSP)反应过程中的结构变化,特别是结晶变化以及结构与反应动力学的关系,对SSP进程中不同反应时间的聚酯样品的特性黏度及端羧基含量进行了测试,并通过X-射线衍射、差...     

Effects of the Water in Mixed Solvent on the Epoxidation Reaction of Propylene with TS-1 Catalyst

The epoxidation reaction of propylene and hydrogen peroxide with zeolite catalyst containing titanium-silicalite (TS-1)has been studied, and the reaction in the mixed solvent of water/methanol has been discussed. It is shown that the selective of epoxidation propylene decreases while the selective of propylene glycol increases, when the water content increases in the mixed solvent of me thanol/water.     

变径热管纺丝机理的研究

变径热管纺丝是一种新开发的纺丝工艺，通过建立纺丝动力学的模型，对不同的工艺条件进行模拟，计算出纤维沿纺程上的温度，速度及应用分布，找出纺丝工艺参数的调节规律。     

纺丝速度对涤纶FCY的无定形结构影响的研究

在3000～5000m/min纺速下制备Fully Crystallinity Yam(FCY)纤维,利用X光衍射、密度梯度等测定了无定形区的含量;并结合声速计算得到无定形区的平均取向。在M-K理论的基础上,重新定义了结构化指数,并计算得到无定形区的微细结构分布。结果表明:在其它工艺条件不变,热板位置、温度、长度分别为544mm、200℃、1800mm时,涤纶FCY的最佳纺丝速度为3 500m/min。即在3 500 m/min纺速形成的无定形结构较均匀、致密。其无定形含量低,无定形取向高,动态力学转变温度高。从tanδ～T曲线可以计算无定形区的分布,在3 500m/min纺速n_(max)、《n》及aum from ≥4 F(n)等较高,峰面积较小,相应的无定形结构较强,无定形含量较低。所得结果与其它方法的结果一致。从tanδ～T曲线可以计算无定形区的分布,且本方法与其它方法相比,更灵敏,更有效,可获得更多的信息。     

涤棉混纺织物近红外定量分析模型的建立及相关问题探讨（英文）

在废旧纺织品回收再利用中,纤维类型和含量的快速、准确测定是回收方案的关键部分。以598个废旧涤棉混纺织物为研究对象,采用便携式近红外(NIR)光谱仪测试了样品的原始近红外光谱。在1 400～1 700和1 900～2 200nm光谱区域,100%棉和100%聚酯样品的光谱存在明显差异,并且这些光谱差异存在于各种颜色纤维上。同时探讨了斜线光谱产生的原因可能是由于织物表面效果、着色方法及粘附在纤维表面的细小颗粒造成的。深色样品易造成其光谱基线在短波区发生漂移,经导数预处理后,基线漂移基本消除,斜线光谱呈现出正常光谱的特征。利用偏最小二乘(PLS)法结合一阶导数、S-G平滑、均值中心化和正交信号校正法,建立了废旧棉-涤混纺织物定量分析模型。为了验证模型的可靠性,选取346个样本采用内部交叉验证均方根误差(RMSECV)和预测样品集外部检验法对模型进行检验,模型的RMSECV值0.002、校正集相关系数RC=0.998、预测相关系数RP=0.997、预测标准差SEP=1.121,模型预测正确率可达97%。对模型进行匹配样本t检验结果显示,NIR方法与国家标准方法无显着性差异。NIR预测值与重量法测定值误差在±3%以内时,二者的一致性在90%以上,当误差在±5%以内,二者的一致性在95%以上,分析时间小于10s。因此,利用近红外技术结合所建模型可以快速、准确地预测废旧棉/涤混纺织物纤维成分的含量。     

涤棉混纺织物近红外定量分析模型的建立及相关问题探讨

在废旧纺织品回收再利用中,纤维类型和含量的快速、准确测定是回收方案的关键部分。以598个废旧涤棉混纺织物为研究对象,采用便携式近红外（NIR）光谱仪测试了样品的原始近红外光谱。在1 400～1 700和1 900～2 200 nm光谱区域,100％棉和100％聚酯样品的光谱存在明显差异,并且这些光谱差异存在于各种颜色纤维上。同时探讨了斜线光谱产生的原因可能是由于织物表面效果、着色方法及粘附在纤维表面的细小颗粒造成的。深色样品易造成其光谱基线在短波区发生漂移,经导数预处理后,基线漂移基本消除,斜线光谱呈现出正常光谱的特征。利用偏最小二乘（PLS）法结合一阶导数、S-G平滑、均值中心化和正交信号校正法,建立了废旧棉-涤混纺织物定量分析模型。为了验证模型的可靠性,选取346个样本采用内部交叉验证均方根误差（RMSECV）和预测样品集外部检验法对模型进行检验,模型的RMSECV值0.002、校正集相关系数R_C＝0.998、预测相关系数R_P=0.997、预测标准差SEP＝1.121,模型预测正确率可达97％。对模型进行匹配样本t检验结果显示,NIR方法与国家标准方法无显着性差异。NIR预测值与重量法测定值误差在±3％以内时,二者的一致性在90％以上,当误差在±5％以内,二者的一致性在95％以上,分析时间小于10 s。因此,利用近红外技术结合所建模型可以快速、准确地预测废旧棉/涤混纺织物纤维成分的含量。     

Synthesis and Characterization of Poly[ 2, 2- （m-phenylene） -5, 5-bibenzimidazole ] in 1-butyl-3-methylimidazolium Chloride

Poly[2,2-(m-phenylene)-5,5-bibenzimidazole](mPBI)were synthesized by mixing 3,3’,4,4’-tetraaminobiphenyl and isophthalic acid in 1-butyl-3-methylimidazolium chloride([BMIM]Cl).Intrinsic viscosity of mPBI polymers was 0.67 dL/g which was measured in 96%sulfuric acid.The polymer was characterized by Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance(1H-NMR),and thermogravimetric analysis(TGA).The effects of polymerization conditions on the intrinsic viscosity of mPBI were investigated.It showed that the molecular weight of polymer mainly depended on pre-reaction time and reaction temperature.Comparison of structure and properties of mPBI synthesized in ionic liquids(ILs)and polyphosphoric acid was also reported.It indicates that the ionic liquids are a kind of good solvents in synthesis process of mPBI and ionic liquids mainly affect molecular weight of mPBI.