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研究了纳米远红外涤纶纤维的红外谱图、热性能、物理机械性能及远红外发射、保温和抑菌性能,并与普通涤纶纤维作了对比。研究结果表明,纳米材料颗粒在纤维中的分布较均匀,基本上无团聚现象;纳米材料的加入没有影响涤纶纤维的基本结构和热性能;与普通涤纶纤维相比,纳米远红外涤纶纤维的断裂强度和断裂延伸度略有降低,但变化不大;纳米远红外涤纶纤维具有优异的远红外发射性能、保温性能和较好的抑菌性能。 相似文献
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为了拓展天然纤维素材料的应用,在综合国内外对天然纤维素材料、纳米材料和抗菌材料相关研究的基础上,首先,利用LiCl/二甲基乙酰胺(DMAC)溶剂体系配置了不同共混比例的天然纤维素/聚丙烯腈纺丝液,采用静电纺丝技术制备了纤维素/聚丙烯腈纳米纤维。然后,用铜氨溶液对纳米纤维进行了抗菌处理,制备了具有一定抗菌功能的纤维集合体。最后,采用SEM观察不同共混比例下纳米纤维的微观形貌;采用TG和DSC表征其热性能;采用FTIR和表面接触角测量仪表征共混后纳米纤维的化学组成和亲水性的变化;采用振荡法测定纳米纤维的抗菌性能。结果表明:通过静电纺丝技术可制得直径在200~400nm范围内的纤维素/聚丙烯腈纳米纤维。随着纤维素含量的提高,纳米纤维的表面越来越粗糙,粘连愈加严重,且直径离散度也变大。当纤维素与聚丙烯腈的共混质量比大于75∶25时,纤维的直径标准偏差由纯聚丙烯腈纤维的100nm以下变为150nm以上。纤维素/聚丙烯腈纳米纤维具有良好的热性能,与纯纤维素纳米纤维相比热稳定性有一定提高,当纤维素与聚丙烯腈的共混质量比为25∶75时热稳定性最好。纤维素/聚丙烯腈纳米纤维的亲水性优于普通医用纱布的。经过铜氨溶液抗菌处理的纳米纤维具有良好的抗菌性能,对金黄色葡萄球菌和大肠杆菌的抑菌率分别为82%和75%。 相似文献
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利用静电纺丝技术制备了不同纺丝时间的聚对苯二甲酸乙二醇酯(PET)纳米纤维膜,将PET纳米纤维膜、热熔型胶膜及涤纶针刺毡通过热处理复合,制备了三明治结构的PET纳米纤维膜/涤纶针刺毡过滤复合材料,利用SEM分析了PET纳米纤维膜形貌,通过TGA确定了PET纳米纤维膜的热处理条件,对不同纺丝时间的PET纳米纤维膜/涤纶针刺毡过滤复合材料透气性能、过滤性能进行了研究。结果表明:纺丝液浓度为18%,纺丝电压为15 kV,接收距离为21 cm,环境温度为13℃,环境湿度为20%条件下得到的PET纳米纤维膜纤维平均直径为514.95 nm;PET纳米纤维膜与涤纶针刺毡的复合温度为115℃;随纺丝时间的增加,PET纳米纤维膜的密度增加,PET纳米纤维膜/涤纶针刺毡过滤复合材料对颗粒物的过滤效率增大,透气性下降,当密度为3.86 g/m2时,PET纳米纤维膜/涤纶针刺毡过滤复合材料的过滤性能最优,其品质因子QF明显优于常规涤纶针刺毡,对1 μm以下颗粒物的过滤效率均高于93%,效率提高了58%以上,表现出优异的过滤性能。 相似文献
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静电纺丝制备肉桂醛/聚乳酸复合纳米纤维膜及其性能 总被引:1,自引:0,他引:1
采用水溶液饱和法制备了肉桂醛/β-环糊精包合物,将其添加到聚乳酸(PLA)溶液中,采用静电纺丝技术制备了肉桂醛/PLA复合纳米纤维膜。利用扫描电子显微镜对复合纳米纤维膜的直径及表面形貌进行观察,通过红外光谱对其做特征官能团分析,同时对其热力学性能、力学性能及抗菌性能进行表征。结果表明,肉桂醛/PLA复合纳米纤维膜纤维形态良好,其直径范围在133~177nm。红外光谱显示肉桂醛与PLA属于物理混合;随着肉桂醛/β-环糊精包合物添加量增加,其纤维膜拉伸强度逐渐降低,但玻璃化转变温度变化不显著。纤维膜对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌都具有抑菌性能,且随着包合物添加量的增加抑菌性逐渐增强,其中对金黄色葡萄球菌抑菌性最强。 相似文献
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纳米ZnO的抗菌性能研究 总被引:1,自引:0,他引:1
纳米ZnO是一种常见的光学材料,将其与其他材料复配可以制得抗菌性能良好的包装材料。根据GB/T 21510—2008《纳米无机材料抗菌性能检测方法》,以大肠杆菌和金黄色葡萄球菌为测试菌种,以SiO2为对照试验,测试了纳米ZnO对大肠杆菌和金黄色葡萄球菌的抗菌性能;同时,采用抑菌圈法对其抗菌性能进行了定性研究。结果表明:纳米ZnO对大肠杆菌和金黄色葡萄球菌具有良好的抑菌性能,且初步测定了纳米ZnO对这两种菌的最小抑菌浓度,分别为0.312 5%和0.625%;纳米ZnO对大肠杆菌和金黄色葡萄球菌高度敏感,纳米ZnO对二者的抑菌圈直径都大于15 mm。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
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A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.…… 相似文献
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Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster. 相似文献