有序介孔复合炭膜的制备及其性能研究

采用软模板法合成有序介孔炭(OMC),利用XRD、TEM及SEM等分析方法对其进行结构性能分析,探讨了催化剂和模板剂的种类及用量、反应温度等合成工艺条件对形成OMC结构性能的影响。以最佳工艺条件制备的OMC前驱体为涂膜液涂敷在管状微滤炭膜表面,经炭化制得有序介孔复合炭膜,而后考察了复合炭膜的气体渗透性能。结果表明:以盐酸为催化剂、模板剂F127/间苯二酚摩尔比为0.0081、反应温度为30℃时,可合成有序程度最佳的OMC前驱体。用该OMC前驱体涂敷微滤炭膜制备的有序介孔复合炭膜,改善了微滤炭膜的孔结构,最大孔径由0.530μm减小至0.299μm,同时提高了炭膜的气体渗透通量。其中,由混煤微滤炭膜所制有序介孔复合炭膜,N2气渗透通量达1.18·10-8m3·m-2·s-1·Pa-1,是未经修饰烟煤微滤炭膜的4倍。     

多级孔炭电极材料的制备及其性能研究

以聚醚F127、间苯三酚和甲醛为原料,采用KOH活化法制备出具有介孔、微孔的多级孔炭材料,利用BET、XRD、SEM对样品的组成和结构进行了表征.结果表明:随着升温速率的增加和炭化时间的减少,介孔炭材料的比表面积、孔容以及介孔表面积先增大后减小.10℃/min条件下可获得最优性能的介孔炭,其介孔表面积为324.47m2...     

用软模板法制备有序介孔炭材料过程的研究

采用软模板法合成有序介孔炭材料,并通过热重分析、低温氮吸附-脱附测量、小角XRD、透射电镜和傅里叶变换红外光谱等分析表征手段,分别考察了有机模板剂脱除和炭化过程对生成有序介孔炭结构和性能的影响。研究结果表明,在N2气氛下350℃焙烧5h可有效脱除有机模板剂,获得具有有序介孔结构的炭材料前驱体;该材料在500~800℃炭化后可生成有序介孔炭材料,其孔径分布变化不大,但比表面积和孔容有较大程度提高,提高部分主要集中分布在微孔区,最佳炭化温度为600℃。     

成膜基质对炭膜结构与气体分离性能的影响

以间苯二酚-甲醛为碳源,F127为添加剂,经成膜与炭化得到炭膜.通过热失重分析、红外光谱、元素分析及透射电镜从微观上分析了前驱体的热解过程及碳结构演变.采用X射线衍射及氮气吸附技术分别测定了炭膜碳结构与孔结构.研究了成膜基质表面疏水性对成膜过程的收缩率、碳结构、孔结构及气体分离性能的影响.结果显示,成膜基质对炭膜微观结构与分离性能影响显著.疏水性较大的玻璃比聚四氟乙烯与不锈钢更有助于减小成膜过程中径向收缩率,并得到高比表面积与孔体积的炭膜,其对O2/N2选择性高达10以上.     

一步法合成具有二级孔道的有序介孔碳材料及其超电容性能研究

以酚醛树脂低聚物为碳前驱体,三嵌段共聚物F127为模板剂,在此过程中加入正硅酸乙酯为硅源,900℃下炭化得到具有介孔结构的碳-SiO2复合物,除SiO2后得到具有二级孔道结构的介孔碳材料.对样品进行透射电子显微镜、N2吸附-脱附表征,并利用循环伏安以及恒电流充放电研究了样品的超电容性能.结果表明,样品具有二级孔道结构,BET比表面积为1657.6m2·g-1,比电容值161.3F·g-1.相比于单一孔道的介孔碳材料,二级孔道结构的介孔碳的循环伏安曲线更接近于矩形,比电容值有了很大提高,随着放电电流的增大其比电容值衰减率更小.     

以一种新碳前驱体制备有序介孔碳及其表征

分别采用两亲性三嵌段共聚物F127、P123以及F127/P123复合物为模板剂,线性酚醛树脂/六亚甲基四胺固化物为碳源,利用有机-有机自组装法制备了具有二维六方结构和蠕虫状结构的介孔碳材料。采用FT-IR、XRD、TEM、低温N2吸附/脱附、TG和元素分析等方法表征了介孔碳的结构,研究了不同的模板剂对介孔碳结构的影响。结果表明,以F127为模板剂制备的介孔碳具有规则的二维六方结构,其比表面积、微孔表面积、孔容、孔径和孔壁厚度分别为670m2/g、368m2/g、0.40cm3/g、3.2nm和4.5nm。以P123为模板剂制备的介孔碳具有蠕虫状结构,其比表面积、微孔表面积、孔容和孔径分别为506m2/g、251m2/g、0.27cm3/g和3.0nm。以F127/P123复合物为模板剂制备的介孔碳的孔径相对于单一模板剂有所提高,其比表面积、微孔表面积、孔容和孔壁厚度均随着复合模板剂中F127质量分数的降低而降低。     

预氧化处理对聚醚酰亚胺基炭膜结构与气体分离性能的影响

以新型聚醚酰业胺预聚体一聚酰胺酸为前驱体,在空气中进行预氧化处理后经700℃炭化制备出炭膜.采用红外光谱(FTIR)、元素分析(EA)、X射线衍射(xRD)和气体渗透等测试手段对400℃、460℃和480℃温度下所制预氧化膜的化学结构、炭膜的微结构和气体分离性能进行了表征.结果表明:预氧化阶段,聚合物链发生了热分解和氧化交联反应,温度越高,热分解和氧化程度越高.炭化后,预氧化膜的交联结构演变成无定彤碳结构.预氧化膜的结构差异导致了炭膜的孔结构的不同,从而对炭膜的气体分离性能产生重要影响,其中经460℃预氧化处理后所制炭膜的O2渗透系数可达8.2×10-13(m3(STP)·cm)/(m2·s·Pa),O2/N2选择性达14.1.     

有序介孔炭材料表面电活性氧基团的构造及其超级电容器性能

以酚醛树脂为前体,表面活性剂F127为软模板,通过蒸发诱导自组装法制备了有序介孔聚合物,将其水热负载氢氧化镁并在高温下进行碳化得到具有有序介孔结构和丰富活性氧基团的有序介孔炭材料。系统研究了水热浸渍温度对所得材料表面积、孔体积及超级电容器性能的影响。结果表明:随着温度的升高,氢氧化镁负载量升高,但其表面积下降,最佳的水热浸渍温度为150℃,在该温度下水热浸渍的氢氧化镁的负载质量为3.3%,所得材料的表面积为326m~2/g,其作为电极用于超级电容器的容量为212F/g。     

SBA-15模板法有序多孔炭膜材料的制备及表征

以介孔分子筛SBA-15为模板剂,聚酰亚胺为前驱体,经共混、成膜、炭化及脱模板过程,制备了有序多孔炭膜材料(OPCM)。通过热失重、红外光谱、电子显微镜和X-射线衍射,分别对前驱体热稳定性、膜表面官能团、微观形貌与微观结构进行了表征。考察了SBA-15脱除前后的炭膜微观结构与形貌,及OPCM气体分离性能。结果显示,当炭化温度为650℃、SBA-15用量为1%时,所制得OPCM的气体分离系数显著高于努森扩散。     

聚醚酰亚胺基炭分子筛膜的形成及其气体分离性能研究

以商用聚醚酰亚胺(PEI)作为前驱体,采用经过ZrO2-Al2O3复合溶胶修饰的陶瓷氧化铝为支撑体,浸渍涂膜制备聚合物膜,在空气中预氧化处理后,经500～800℃不同的炭化温度下制备出气体分离炭分子筛膜。为了考察炭化温度对炭膜结构和气体分离性能的影响,采用热重分析(TG)、拉曼光谱(Raman)、X射线衍射(XRD)、扫描电镜(SEM)和气体渗透等测试手段,对热解过程聚合物膜热稳定性、炭微晶结构及石墨化进程、微观形貌和气体分离性能进行了系统研究。结果表明,不同的炭化温度对所形成炭膜表现出不同物理和化学结构、炭结构和孔结构,最终影响炭分子筛膜的气体渗透性和分离选择性。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

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.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

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.……     

Optimum-Simulation von Ernteprozessen

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.     

A study of centrifugal cast high boron high speed steel

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

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 ...     

Brainstorming for ISO Strategy 2016-2020

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     

CNAS Passes APLAC's PTP Review

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.