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采用溶胶-凝胶技术,在多孔Al2O3载体上制备了一层适合于涂覆分离膜的γ-Al2O3多孔过渡膜.通过XRD与DTA-TG等测试手段研究了γ-Al2O3凝胶膜在热处理过程中的物理化学变化;通过TEM、SEM分析与泡点法研究了多孔膜的微观结构.实验结果表明:实验中制备的γ-Al2O3膜具有择优取向的特点;γ-Al2O3过渡膜的最可几孔径为0.38μm左右,厚度为4μm.薄膜的渗透性能测试结果表明,材料对H2与N2气的最大分离系数α=3.30. 相似文献
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采用不含有机模板剂的晶化液在平均孔径为2μm的多孔α-Al2O3管上合成了ZSM-5沸石膜.纳米ZSM-5沸石晶种的摩尔组成为9TPAOH25TEOS0.25
Al2O3480H2O.多孔α-Al2O3载体管外表面用这些粒度为100nm左右的晶种悬浮液浸涂、干燥后,依据纳米ZSM-5沸石晶种的DTA/TG进行煅烧,在不含有机模板剂的摩尔组成为67Na2OAl2O3240SiO26000H2O晶化液中合成了ZSM-5膜.XRD确定膜晶体为ZSM-5沸石,SEM表明沸石膜无缺陷,膜厚度约为8μm.制备的ZSM-5沸石膜H2的渗透率为1.50×10-6mol.m2·S-1.Pa-1,理想分离因数αH2/N2为3.85左右. 相似文献
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硼掺杂的γ-Al2O3催化膜的制备及其热稳定性的研究 总被引:6,自引:0,他引:6
在勃姆石AIOOH溶胶中引入一定量的H2BO3溶液,经不同温度的热处理,,制成不同硼掺杂含量的无支撑的γ-Al2O3催化膜,用XRD,BET分别对膜的晶相和膜的微孔结构,包括比表面积,孔径和孔容进行了研究,结果发现,随着硼含量的增加,在低温下,膜的比表面积和孔容都不断增加,而对孔径的影响不大,经1200度处理后,未掺杂硼的膜的比表面积,孔径和孔容分别为5.4m2/g,49nm和0.063cm2/g,而经掺杂16%摩尔硼的膜的比表面积,孔径和孔容分别为35m2/g,13nm和0.225cm3/g,这说明硼的掺杂对γ-Al2O3膜的热稳定性有很好的改善作用。 相似文献
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电泳沉积法所制γ-Al2O3微孔膜的结构和性能的研究 总被引:3,自引:1,他引:2
以制得的Al(OH)3溶胶为电泳液,用电泳沉积法制备了平均孔径为4.6nm的γ-Al2O3微孔膜。采用SEM、孔径分布等测定方法考察了γ-Al2O3膜的微观形貌和孔结构,并研究了其气体透过性。结构表明,γ-Al2O3膜表面是平整的,未见明显开裂,且膜上有气孔存在。随着焙烧温度的升高,γ-Al2O3晶粒长大,形态变得更加规整,粒径大小均匀;孔径分布集中性降低,大孔比例、孔容及孔隙率都有显著增在,表明控制焙烧温度可调探孔大小及其分布。气体H2/N2和O2/N2可充分透过γ-Al2O3膜,其气体透过机理应为努森扩散为主。 相似文献
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微波水热合成γ-AlOOH和γ-Al2O3纳米片 总被引:1,自引:0,他引:1
以九水合硝酸铝和尿素为原料,聚乙烯吡咯烷酮为表面活性剂,在180℃微波水热条件下反应30min,制备了γ-AlOOH片状结构产物。此前驱物经600℃热分解2h,得到γ-Al2O3纳米片。采用SEM、TEM、SAED和XRD等方法对样品进行表征,并测试了γ-Al2O3纳米片对刚果红染料的吸附性能。实验结果表明,采用微波水热法可以得到长度约为1μm,厚度为30nm的γ-AlOOH纳米片,该产物经煅烧处理后可以得到微观形貌保持不变的γ-Al2O3纳米片,且片状结构表面存在介孔结构。γ-Al2O3纳米片状结构表现出对废水中刚果红污染物的强吸附性能。 相似文献
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从无机铝盐出发,采用原位造粒技术,在自制的圆板状α-Al2O3载体表面上成膜,研究了原位造粒成膜的一些影响因素,并与溶胶-凝胶法以乙醇铝制备的载体γ-Al2O3膜进行了孔结构、表面状态和气体渗透性等性能和成膜机理的比较.结果表明:原位造粒法从无机铝盐出发可以制备具有微孔结构无针孔的γ-Al2O3膜.而且,具有如下优良品性:(1)膜的厚度薄而均匀、完好率大,膜厚度可控制在~1μm的水平,比乙醇铝水解溶胶-凝胶法制得的膜厚度~5μm薄得多;(2)具有良好的气体渗透性能,在保持基本相同的分离因子增量的情况下,其渗透率的减少量比乙醇铝水解溶胶-凝胶法的少得多;(3)在载体表面的微孔口原位造粒,粘着性好,不易脱落,而且粒径和孔径的大小可以通过浸渍时间及氨处理来调节等. 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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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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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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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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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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《中国标准化(英文版)》2014,(4)
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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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献