圆柱-圆锥型喷水孔的流体动力特性

为研究圆柱-圆锥型喷水孔的流体动力特性,采用不可压缩二维轴对称N-S方程,利用“RNG”k-ε湍流模型与VOF多相流模型和有限体积法对高压高速自由射流场进行数值模拟.模拟结果表明,对于入口转角为直角的轴对称喷水孔口,水在孔口入口处与壁面分离并开始收缩,收缩后的水针与孔口壁不再接触,两者被逆流而上的空气隔开.收缩水针所表现出来的流动特性符合水刺生产要求.通过数值模拟,了解了喷水孔内外流场的流动状态以及流场各参数在空间的变化规律,为喷水孔的设计与选择提供计算依据.     

Effect of Inclined Water Jets on Tensile Strength of Bicomponent Hydroentangled Nonwoven Fabrics

The effects of inclined water jets on bicomponent hydroentangled fabrics were investigated. The PET/COPET and PA6/PET hydroentangled fabrics were made by using designed inclined water jet apparatus. Effects of basis weight, water jets inclination angle and water jet pressure were discussed. The comparison was made on the average tensile strength of fabrics made by perpendicular water jets （0^o inclination angle） and inclined water jets of 20^o with pressure levels of 3 bars and 7 bars. It was found that increases of water jet pressure, the fabrics tensile strength were increased. Furthermore, increases of water jets inclination angle, fabric tensile strength of 60 g/m^2 fabrics decreased while for 100 g/m^2 fabrics tensile strength increased.     

MEM纳米复合非织造材料的过滤性能

为了研发高效低阻过滤材料,采用正交设计的试验方法,研究了纳米纤维直径、纳米纤维材料的厚度和不同熔喷材料对熔喷-静电纺-熔喷(MEM)纳米复合非织造材料过滤性能的影响.结果表明,纳米纤维材料的厚度和纳米纤维直径对材料的过滤性能影响最大,通过复合一层很薄的纳米纤维膜(0.029~0.116μm),熔喷材料的过滤效率从38.100%提高到99.429%以上,品质因数提高近2倍.该材料能够有效拦截空气中的PM2.5和病毒等微小有害粒子,可应用于高性能防护口罩.     

亲水整理对医用聚丙烯SMS脂肪纯化材料性能的影响

采用亲水剂喷淋-烘焙的方法和正交试验对聚丙烯纺黏-熔喷-纺黏(SMS)非织造脂肪纯化材料表面进行亲水整理,通过扫描电子显微镜、傅里叶变换红外光谱仪、接触角测量仪、倒置显微镜等仪器,对亲水整理前后聚丙烯SMS非织造材料的微观形态、化学结构、亲水性能、细胞毒性、纯化效果等进行表征。结果表明:亲水整理工艺中亲水剂质量分数、烘干温度、烘干时间分别为7%、100℃、140s时,整理后的聚丙烯SMS非织造材料的液体穿透时间最短;亲水整理后聚丙烯SMS非织造材料孔径分布更加集中且无细胞毒性;与医用棉纱布过滤法、离心法等相比,采用经亲水整理的聚丙烯SMS非织造材料进行过滤对脂肪的纯化效果最好。     

海藻酸钙纤维基本性能的研究与表征

对海藻酸钙纤维的表观结构、吸湿性能、基本力学性能、成凝胶性能、耐热性进行研究与表征.研究发现:海藻酸钙纤维表面有沟槽,且沟槽形状多样、均匀性较差;海藻酸钙纤维吸湿能力很强;纤维力学性能较差,是一种低强低伸纤维,但其初始模量较大,纤维较硬脆;海藻酸钙纤维的耐热性较差,处理温度达到90℃后,纤维力学性能急速下降;纤维经生理盐水作用成凝胶后,形成独特的类似"皮芯"的结构,纤维力学性能明显下降.     

SMS手术衣材料的“三拒一抗/单向导湿”双面泡沫整理

采用泡沫整理法对纺黏-熔喷-纺黏(SMS)手术衣材料进行一面亲水整理一面三拒(拒酒精、拒油、拒血液)一抗(抗静电)整理,使材料在具有防护性的同时具有单向导湿性能.通过9组正交试验得出最优试验配方:亲水剂质量浓度为30g/L,防水剂质量浓度为75g/L,抗静电剂质量浓度为75g/L,烘干温度为80℃,烘干时间为4min,焙烘温度为120℃,焙烘时间为3min.     

Geotube Application in Land Reclamation from Sea

The geotubes have been widely applied in the engineering of land reclamation from sea. At present three kinds of material can be used to make geotubes: splitting film,fibrillated splitting film and multifilament. The geotubes made of these materials have their advantages and disadvantages. In engineering application to know the rule of forces change is very important. Based on geometry way,limit-filling height of geotubes is determined. Experiment in Pudong International Airport reflects that packing soil height of small-size geotubes will be smaller than that of large-size geotubes.     

Numerical Simulation of the Air Jet Flow Field in the Melt Blowing Process

The theoretical model of the flow field of the dual slot die in melt blowing process is founded. The model is solved numerically with finite difference method. The distributions of the air velocity component in x direction along x-axis and y-axis and the air temperature distributions along x-axis and y-axis are obtained via numerical computation. The computation results coincide with the experimental data given by Harphain and Shambaugh. The distributions of the air velocity and air temperature are introduced into the air drag model of melt blowing. The model prediction of the fiber diameter agrees with the experimental data well.     

对熔喷气流拉伸一维数学模型的改进研究

改进了Shambaugh等提出的熔喷气流拉伸一维数学模型,考虑了聚合物熔体密度和比定压热容随温度变化时的情况,引入了幂律流体本构方程,并讨论了聚合物体积流量等参数对纤维直径的影响.     

佛道文化与唐代武侠小说

唐代武侠是最早的具有现代意义的武侠，唐代武侠小说的模式预示了后代武侠小说的发展方向，标志着以写实为特点的侠客传记向以虚构幻想为特点的武侠小说的转变；唐代佛道文化的繁荣鼎盛，是这种转变的原因。