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1.
采用聚合物溶液和熔体浸润多孔阳极氧化铝(AAO)模板的物理方法,成功制备了通孔的热塑性聚氨酯(TPU)纳米管及其阵列结构.扫描电子显微镜(SEM)和透射电子显微镜(1EM)测试表明:有效地调整溶液滴加量可制备出不同结构的聚合物纳米管阵列.以浓度为7.0%(wt)TPU溶液为例,研究了溶液滴加量对纳米管结构之间的关系,2μL为制得TPU纳米管阵列结构的最佳滴加量.并探索首次浸润程度对纳米管结构的影响,完善了模板浸润法的多次浸润机理.  相似文献   

2.
以孔径为200nm的多孔氧化铝膜(AAO)为模板、常规分子量的通用聚合物为原料,采用聚合物溶液或熔体浸润模板纳米孔的物理技术,进行了多种聚合物纳米管的制备研究。结果表明:聚苯乙烯、尼龙66、聚丙烯、ABS、热塑性聚氨酯等多种聚合物纳米管及其纳米管阵列成功制得。运用扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察了纳米管的微观形貌和阵列结构。并探讨了聚合物性质、纳米管制备工艺与纳米管结构的关系,初步探索了多孔模板法制备聚合物纳米管的机理。  相似文献   

3.
采用溶液浸润多孔阳极氧化铝模板(AAO)的方法,在孔径为200nm的AAO模板中制备功能聚合物聚乙烯咔唑(poly(vinyl carbazole),PVK)一维纳米结构.SEM和TEM测试结果表明,2.5%和3.5%(质量分数)的PVK溶液可制得纳米管,其外径约为200nm,管壁厚度分别为30与70nm;而5.0%与10.0%(质量分数)的PVK溶液可制得纳米线,其直径约为200nm.提出了溶液浸润模板法中的完全浸润体系和部分浸润体系以及临界浸润浓度Cw.  相似文献   

4.
张璐  姚素薇  张卫国  王宏智 《功能材料》2005,36(11):1765-1768
以多孔阳极氧化铝(AAO)为模板,利用扩散聚合法让苯胺单体溶液和氧化剂溶液在一维纳米孔道中相互扩散,在孔内形成聚苯胺(PANI)纳米管和纳米线阵列。利用SEM、TEM、IR和XRD等检测技术对阵列进行表征。结果表明,聚合反应优先发生在孔壁上,并沿孔壁逐层生长,直至形成实心的纳米线阵列。在孔径为60nm的AAO模板内,扩散聚合40min可形成聚苯胺纳米管阵列,2h后形成聚苯胺纳米线阵列;聚苯胺纳米管(线)中同时包含结晶相和无定型相结构。用二探针法测量PANI/AAO复合阵列电阻,计算出单根聚苯胺纳米线的电导率为21.4S/cm。此外,对扩散聚合过程中聚苯胺纳米管(线)阵列的形成原因进行了初步分析和探讨。  相似文献   

5.
首先在KF和乙二醇的混合溶液中利用阳极氧化技术在钛基底表面制得了一层排列整齐、形貌均一的TiO2纳米管阵列薄膜,然后将制得的薄膜进行水热处理,通过扫描电子显微镜、X射线衍射仪等表征手段研究了水热处理温度和时间对TiO2纳米管阵列薄膜表面形貌、结晶度以及管状结构的影响。结果表明:水热处理即使在较短的时间内(如3 h)也可在较低温度下(如210℃)使TiO2纳米管阵列薄膜由无定形转变为锐钛矿型结构;提高水热处理温度或延长水热处理时间均可提高薄膜的结晶度,但同时纳米管管壁结晶度增加会使管内径变小甚至堵塞,从而破坏管状结构。  相似文献   

6.
采用一种简单的物理技术——聚合物溶液或熔体浸润多孔阳极氧化铝(AAO)模板的方法,在孔径仅为200nm的AAO模板中制备聚苯乙烯(PS)纳米管阵列。SEM和TEM测试结果表明:熔体法制备的纳米管壁厚约为110nm;5.0wt%和10.0wt%的PS溶液制备的纳米管壁厚分别为70nm和80nm。并初步探索了模板法制备聚合物纳米管的多次浸润机理。  相似文献   

7.
采用电化学阳极氧化法在纯钛片表面制备出了结构整齐有序的TiO2纳米管阵列, 主要研究了电解液的性质、浓度以及氧化时间对TiO2纳米管阵列形貌的影响, 并对不同电解液中TiO2纳米管阵列的形成机理进行了初步探讨. 结果表明:在不同浓度的HF酸电解液中均可制备出规则、均匀的TiO2纳米管阵列, 管径均匀, 表面平整, 但是纳米管的长度均较短, 约为300~350nm. 在高浓度HF电解液中, 同时获得了规则的纳米管阵列和纳米棒阵列. 在0.5wt% NaF和1mol/L Na2SO4中性电解液中也可以制备出表面光洁、排列整齐有序的TiO2纳米管阵列, 纳米管长度明显长于HF酸电解液中获得的纳米管阵列, 达到了700nm, 但是阵列的表面平整度较差. 在乙二醇+0.6wt% NH4F+2vol% H2O有机电解液体系中可以制得超长的TiO2纳米管阵列, 管径在150nm左右, 管长可达6μm.  相似文献   

8.
阳极氧化法制备TiO2纳米管阵列及其光电性能研究   总被引:6,自引:0,他引:6  
采用阳极氧化法在钛片上制备了TiO2纳米管阵列光电极,利用扫描电子显微镜(SEM)和X射线衍射仪(xRD)对TiO2纳米管的形貌和结构进行了表征,详细考察了氧化工艺参数对纳米管阵列形貌的影响,并通过稳态光电响应技术对TiO2纳米管电极的光电化学性能进行了研究.结果表明,在1wt%HF电解液中,控制氧化电压为20V,反应30min后,在Ti表面获得了垂直导向的TiO2纳米管阵列,孔径约为90nm,管壁厚度约为10nm.经600℃退火处理后,TiO2纳米管阵列为锐钛矿型与金红石型的混晶结构,此时电极的光电性能最佳,与TiO2纳米多孔膜电极相比,光电性能大幅提高.  相似文献   

9.
首次以孔径仅有200nm的阳极氧化铝(AAO)为模板,采用聚合物溶液浸润模板的物理技术,通过不同方法成功制备了常规分子量的PS纳米管及其阵列结构。SEM和TEM测试结果表明,有效地调整和控制制备方法和工艺,可制备出不同管壁厚度的聚合物纳米管.也可制备出管壁带有多孔的纳米管,还可制备出纳米线。探索了多孔模板法制备聚合物纳米管的机理。  相似文献   

10.
用竖式炉流动法,以二茂铁为催化剂,硫为助催化剂,苯为碳源制备碳纳米管(CNT),反应温度为1100-1200℃,碳纳米管的外径为20-40nm,内径10-30nm,长度5-20μm,并在2800℃对碳纳米管进行石墨化处理。用超声分散和溶液浇铸工艺制备碳纳米管,聚甲基丙烯酸甲酯(PMMA)/聚醋酸乙烯酯(PVAc)复合膜和石墨化碳纳米管/PMMA/PVAc复合膜,石墨化碳纳米管复合膜的导电性能明显优于碳纳米管复合膜,石墨化碳纳米管/PMMA/PVAc复合膜和碳纳米管/PMMA/PVAc复合膜的渗流阈值分别为2.5%和5%(质量分数),碳纳米管/PMMA/PVAc复合膜是很好的气敏候选材料。  相似文献   

11.
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   

12.
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   

13.
14.
We associate a variety of innovations with the term "Industry 4.0". The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...  相似文献   

15.
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   

16.
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   

17.
ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.  相似文献   

18.
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   

19.
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   

20.
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from  相似文献   

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