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聚合物材料的吸音系数-温度-频率三元关系的研究 总被引:1,自引:0,他引:1
用驻波管技术研究了聚甲基丙烯酸乙酯(PEMA)和聚氯乙烯(PVC)的吸声系数。结果表明,在玻璃化转变区域材料的吸声系数较高,PEMA和PVC均具有特征吸收频率。当乍于玻璃化转变区域时,PEMA和PVC的特征吸收峰的数目增加,用自由体积理论对此进行了解释。得到PEMA和PVC的吸声系数-温度-频率的三维关系图。 相似文献
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不同聚合物材料具有不同的吸声特征吸收峰,这对于研究聚合物材料的阻尼性能及其应用都有一定的意义。本文利用驻波管吸音系数测试仪测量了聚氧乙烯(PVC)聚合物材料在不同温度及频率下的吸系数,得到了不同频率下吸音系数和温度的关系图,与理论计算得到的谱图拟合较好,进一步的 相似文献
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利用周期性密度泛函的方法,将过渡金属杂原子取代的硅基分子筛的共振拉曼计算结果成功推广到磷铝分子筛体系中.根据对Fe-ZSM-5共振拉曼光谱特点的推广和对Fe-AlPO4-5振动光谱的理论计算结果,预测在Fe-AlPO4-5的共振拉曼光谱的1190、1130、1000-1050和600 cm-1位置附近将出现四条显著的谱带.实验的Fe-AlPO4-5的共振拉曼光谱中确实观察到四条与骨架Fe物种相关的谱带分别位于1210、1130、1050和630 cm-1处,与预测结果一致.另外发现含铁磷铝分子筛的共振振动频率要高于相应的含铁硅基分子筛体系的振动频率,这种频率的差异主要是氧在不同分子筛体系中受力的力常数不同引起的.另外磷氧四面体和铝氧四面体之间的电荷吸引作用对振动频率也有较大的影响. 相似文献
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The acoustical damping property of electrospun polyacrylonitrile(PAN) nanofibrous membranes with different thicknesses and porosities was investigated.The sound absorption coefficients were measured using the impedance tube instrument based on ISO 10534-2:1998(E).Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes.Moreover,the sound absorption performance of the perforated ... 相似文献
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The acoustical damping property of electrospun polyacrylonitrile(PAN) nanofibrous membranes with different thicknesses and porosities was investigated.The sound absorption coefficients were measured using the impedance tube instrument based on ISO 10534-2:1998(E).Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes.Moreover,the sound absorption performance of the perforated panel can be greatly improved by combination with a thin layer of PAN nanofibrous membrane.Traditional acoustical damping materials(foam,fiber) coated with nanofibrous membranes have better acoustical performance in the low and medium frequency range than that of acoustical materials alone.All of the results demonstrate the PAN nanofibrous membrane is a suitable candidate for noise reduction. 相似文献
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Polyester fabric was treated by corona discharge irradiation at different voltages. The treated fabric showed increased wicking and hydrophilic properties and the properties can be preserved for a long time. Dyeing of the treated fabric showed that dyeing speed and the dye-uptake were improved. Surface affinity between the treated fabric surface with modified starch sizing was also confirmed to be increased. This is generally useful for the sizing of polyester staple yarn and the polyester fabric dyeing. All the results are supposed due to the improved hydrophilic properties produced by the corona discharge treatment. 相似文献
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Ting‐Ting Li Xiao Zhang Hongyang Wang Wenna Dai Shih‐Yu Huang Bing‐Chiuan Shiu Ching‐Wen Lou Jia‐Horng Lin 《先进技术聚合物》2020,31(3):451-460
The flexible polyurethane (PU) foam‐filled composite sandwiches are constructed using three types of needle‐punched fabrics (upper layer), PU foam (core layer), and nylon (bottom layer). Different contents of deionized water were used to adjust the pore size and bulk density of PU foam by free‐foaming. Effects of needle‐punched fabric components, cell structure, and fabric‐foam interface on sound absorption and compressive property of the composite sandwiches were investigated. Fabric‐foam interface contributes to improve high‐frequency sound absorption efficiency. When containing 0.5 wt% water in the core and nylon‐glass grid needle‐punched composite fabric (NPUN‐G) in the upper face, the composite sandwiches exhibited optimal sound absorption of 0.78 at low frequency of 450 Hz, and optimal compressive strength of 14.4 kPa. Combination of needle‐punched composite fabric improved the sound absorption coefficient and compressive strength, as high as 223% and 121%, respectively, compared with pure PU foam. This study provided an important basis for the preparation of high‐strength composite sandwiches with low‐frequency sound absorption. 相似文献
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董亚明 《化学物理学报(中文版)》2000,13(3):363-368
沉积在聚脂基片上的表面软化剂DDAC多分子层,在不同的湿度条件下,其横向导电特性标志该表面活性剂在纤维表面处理过程中驱除静电能力的大小。由原子力显微镜(AFM)图像表明,DDAC的2、4、8多分子层薄膜上的结晶颗粒随层数的增加而增大,因此采用电导率描述其导电性质并借助薄膜电阻加以解释。对复合分子层的电导率的非线性变化除借用了半导体物理学中的渗透理论(PercolationTheory)加以解释外,还建立了线束重叠(Patch-Overlapping)模型以讨论电流渗透中的饱和现象。得出了提高相对湿度对可使流经多分子层的电流强度增加的结论同时又对膜厚、湿度对电流强度的贡献及其相互制约的关系提出了理论解释。 相似文献
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以4个杂环芳香胺为重氮组分, 3个N,N-二氰乙基芳香胺为偶合组分, 经重氮化、 偶合反应合成了12个杂环-双氰乙基系列偶氮物; 采用紫外-可见吸收光谱、 红外光谱及核磁共振氢谱等对其结构进行了表征; 还考察了它们在涤纶织物、 乙酰化杉改性木粉和氰乙基化改性木粉上的染色性能. 结果表明, 12个偶氮物为目标产物, 在N,N-二甲基甲酰胺(DMF)中的最大可见吸收波长为417~621 nm, 摩尔吸光系数均大于104. 这些化合物染色涤纶织物的色光分属黄色、 红色、 紫红色和蓝色系列, 并具有高水洗牢度和高日晒牢度; 染色乙酰化木粉和氰乙基木粉的色光和水洗牢度与染色涤纶织物相近. 这12个分散染料具有色谱范围广、 色泽鲜艳、 高发色强度和高牢度等特点, 可用于多种纤维的染色. 相似文献
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合成纤维及其制品吸声性能研究进展 总被引:1,自引:0,他引:1
吸声材料正在朝着装饰性方向发展。合成纤维及其制品(无纺布,纺织品,地毯等)既是高档装饰材料,作为多孔性材料又具有优良的吸声特性。本文介绍了目前关于合成纤维及其制品声学特性的研究状况。 相似文献
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Textile materials can be treated with some enzymes to improve their functionality. The usual enzymatic treatment hydrolyzes the textile surfaces that leads to increase the functional groups. Here, the polyester/wool fabric as a blend of fibers fabric was selected and treated with the two different types of enzymes to increase the surface activity with a propose of higher nano-TiO(2) adsorption. The fabric was first treated with proteases and lipases to hydrolyze the wool and the polyester surfaces, respectively. It has been then dipped into an ultrasound bath containing nano TiO(2) and cross-linking agent followed by curing. The cross-linking agent, butane tetracarboxylic acid (BTCA), also assisted to enhance the nano-particles adsorption and stabilization on the fabric surface. The self-cleaning properties of the fabrics were examined through evaluating the color removal from the stained fabric with Acid Blue 113. The antibacterial properties were determined by reduction growth of a Gram-negative bacteria E. coli. and the UV protection was assessed by UV-reflectance spectrum. The SEM pictures and EDX spectrums of some samples were also reported. 相似文献
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Kozhevnikov VF Payne WB Olson JK McDonald CL Inglefield CE 《The Journal of chemical physics》2004,121(15):7379-7386
Acoustical measurements, electron spin resonance, and Raman spectroscopy have been employed to probe sulfur over the temperature range 80-180 degrees C, which includes the polymerization transition and the supercooled liquid state. Acoustical properties (sound velocity, absorption, and impedance) have been studied with both longitudinal and transverse waves at frequencies between 500 kHz and 22 MHz. The results confirm that polymeric sulfur is a solution of long chain molecules in monomeric solvent, and that the polymerization transition is not a second-order phase transition, as was proposed theoretically. Sulfur is a viscous liquid, but not viscoelastic, both below and above the polymerization transition temperature. It is shown that the classical Navier-Stokes theory is not applicable to the sound absorption in liquid sulfur in the highly viscous state. 相似文献