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将PVA溶于DMSO中,制备完全溶解的PVA/DMSO溶液。将PVA/DMSO溶液与PEDOT∶PSS水分散液共混,制得混合均匀的PVA/DMSO/PEDOT∶PSS共混纺丝液。通过湿法纺丝方法将共混纺丝液挤入甲醇凝固浴以凝固成纤,随后凝固定型的纤维经过不同个数的水洗槽进行水洗而制得不同组别的PVA/PEDOT∶PSS共混纤维。探究了水洗次数对PVA/PEDOT∶PSS共混纤维性能的影响。借助扫描电子显微镜(SEM),红外光谱分析仪(FT-IR),高阻计和电子单纤维强力仪对共混纤维进行测试表征。结果表明:随着水洗次数的增加,纤维表面形貌逐渐变好,表面沟槽和凹陷数量减少,表面变得更加光滑;纤维的电导率逐渐增加;拉伸强度逐渐升高,断裂伸长率逐渐降低。 相似文献
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采用静电纺丝技术,分别制备了聚乳酸(PLA)与茶多酚(TP)质量混比为100/0、90/10、80/20、70/30、60/40、50/50、40/60、30/70和20/80的复合纳米纤维膜.分别借助扫描电子显微镜(SEM)和KDⅡ-0.05微机控制电子万能试验机观察薄膜表面形貌及测试力学性能.SEM图分析结果表明:当PLA与TP的质量混比从100/0变化到50/50时,均能纺出较连续、光滑的纤维.随着纺丝液中PLA含量的减少,TP含量的增加,所纺纤维直径逐渐变小.超出这个范围,纤维断裂现象加剧,甚至出现纳米级颗粒团聚的现象.复合纳米纤维膜的拉伸强度逐渐减小,断裂伸长率先增加后减小. 相似文献
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改性魔芋葡甘聚糖/生物可降解聚酯静电纺丝 总被引:1,自引:0,他引:1
为了制备改性魔芋葡甘聚糖(TDKGM)/生物可降解聚酯纳米复合纤维,以TDKGM和生物可降解聚酯(BP)为原料,三氟乙酸为溶剂,调节TDKGM和BP共混比例,采用静电纺丝方法分别制备了TDKGM/聚乳酸(PLA)、TDKGM/聚丁二酸丁二醇酯(PBS)纳米复合纤维。探讨了TDKGM与可降解聚酯共混比例对纺丝溶液的电导率、表面张力、流变性以及复合纤维直径、形貌和力学强度的影响。随着BP的增加,TDKGM/PLA共混液的表面张力从22.2 N/m降至18.2 N/m,电导率从69.7μS/m下降至39.1μS/m;TDKGM/PBS共混液的表面张力从22.8 N/m降低到17.0 N/m;储能模量、损耗模量、剪切黏度都随之降低;而TDKGM/PBS共混液的电导率变化不成线性规律。当TDKGM/PLA比例为5∶5、TDKGM/PBS比例为6∶4时得到的纤维形貌最为理想,纳米复合纤维的直径分布在400~600 nm,100~500 nm范围,纤维膜的拉伸强度分别为3.557 MPa,4.543 MPa。TDKGM和BP共混比例将影响共混液的电导率、表面张力、流变性,从而影响静电纺丝复合纤维直径分布和形貌,通过控制TDKGM和BP共混比例可以成功地纺丝出纤维直径可控、强度高的TDKGM/BP纳米复合纤维。 相似文献
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《化工新型材料》2016,(7)
以水为溶剂通过静电纺丝手段制备了海藻酸钠/聚乙烯醇(SA/PVA)纳米纤维膜,研究了溶液混合比例、纺丝参数、氯化钠(NaCl)和曲拉通X-100对其静电纺丝的影响,并对SA/PVA纳米纤维膜进行了XRD、FT-IR表征和力学性能测试。结果表明,溶液混配合比和纺丝参数对静电纺丝性能有着重要影响;添加0.5%(wt,质量分数,下同)的NaCl和1.5%的曲拉通X-100后能显著改善SA/PVA的静电纺丝性能。XRD和FT-IR分析表明,PVA能够破坏SA分子间作用力并形成了新的氢键。SA溶液∶PVA溶液的配合比为3∶7时,SA/PVA纳米纤维膜拉伸强度最优,达11.36MPa。 相似文献
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为了改善静电纺再生丝素蛋白(SF)纤维膜的力学性能,通过静电纺丝技术制备丝素蛋白(SF)/聚丁二酸丁二醇酯(PBS)复合超细纤维膜。通过对用甲醇处理后的具有不同共混比例的超细纤维膜进行FE-SEM、FTIR、XRD和DSC观察测试,分析比较了不同共混比例的复合超细纤维膜的形貌、结构,并进行力学性能测试。结果表明:随着聚丁二酸丁二醇酯共混质量比的增加,复合超细纤维的平均直径从289 nm增大到425 nm;复合超细纤维的结晶性能随之提高;复合超细纤维膜的拉伸破坏应力先减小后增大,拉伸破坏应变逐渐增加;当共混质量比为50/50时,复合超细纤维膜表现出良好的力学性能,拉伸破坏应力接近于16 MPa,破坏应变达到50%。聚丁二酸丁二醇酯可有效调控丝素蛋白超细纤维膜的形貌、结构和力学性能。 相似文献
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利用静电纺丝制备出玉米醇溶蛋白(zein)/聚乳酸(PLA)复合超细纤维,通过场发射扫描电镜(FE-SEM)观察了不同共混质量比超细纤维的形貌。然后通过对不同共混质量比的超细纤维膜进行红外光谱(FT-IR)和差示扫描量热(DSC)测试,分析比较了不同共混质量比复合超细纤维膜的结构,并进行了力学性能测试。结果表明,PLA... 相似文献
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以甲酸溶解壳聚糖(CS)、三氯甲烷/乙醇混合溶剂溶解聚乳酸(PLA),两溶液混合后得均质纺丝液,通过静电纺丝制备出CS/PLA复合纳米纤维。采用扫描电镜(SEM)、傅立叶变换红外光谱(FT-IR)对纤维的形态与结构进行分析表征。结果表明,质量分数1.6%的CS甲酸溶液与质量分数15%的PLA三氯甲烷/乙醇混合溶液(三氯甲烷∶乙醇=1∶1,体积比)等体积混合,电压15 kV,极距15 cm下,可得到均匀的直径为(290±28)nm的CS/PLA复合纳米纤维,且CS和PLA分子间以氢键结合。 相似文献
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A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling. 相似文献
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O'Brien RS 《Radiation protection dosimetry》2003,105(1-4):95-100
Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides. 相似文献
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本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。 相似文献
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An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a
rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate
agreement is demonstrated between the derived relations and experimental data. 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue. 相似文献
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V. T. Bublik A. I. Voronin E. A. Vygovskaya V. F. Ponomarev N. Yu. Tabachkova O. V. Toropova 《Inorganic Materials》2011,47(14):1563-1568
An analysis of anisotropy of the properties of a Bi2Se0.3Te2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal
expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological
fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained
using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied. 相似文献