Cu-Bi2WO6的制备及应用于光催化氧化含酚废水的研究

以Bi(NO3)3·5H2O和Na3WO4·2H2O为原料,采用水热法合成了掺杂型可见光催化剂CuBi2WO6,并对其进行X射线粉末衍射(XRD)、紫外-可见漫反射(UV-Vis DRS)、扫描电子显微镜(SEM)表征.结果表明,Cu-Bi2 WO6在不同合成条件下呈现多孔微球和纳米片状结构.以苯酚水溶液为目标降解物,研究了在可见光催化作用下Cu-Bi2WO6的催化性能,实验结果表明掺杂型Cu-Bi2WO6具有比纯Bi2 WO6更高的催化活性.     

纳米氧化铋基材料高温相变的研究

以分析纯Bi(NO3)3·5H2O和Y(NO3)·6H2O为原料制备纳米β-Bi2O3和Bi2O3-Y2O3(75%(摩尔分数)Bi2O3 25%(摩尔分数)Y2O3)粉体,平均粒度分别为40和30nm.经TG-DTA、高温XRD以及高温拉曼的研究结果表明,亚稳态的纳米β-Bi2O3粉体在升温过程中于420℃先向低温稳定的α-Bi2O3转变,在720℃时向δ-Bi2O3相转变,降温过程则是由δ→β→α.由于纳米Bi2O3具有很高的活性,使得相变温度比微米Bi2O3有所降低.纳米Bi2O3-Y2O3复合粉体升温过程中,Y2O3的固溶反应在较低温度(400℃)开始,500℃时β-Bi2O3完全转变为δ相,同时Y2O3完全固溶到δ-Bi2O3晶体中.Y2O3的掺杂使得Bi2O3的β→δ相转变温度大幅降低.     

Yb:KGd(WO4)2激光晶体结构与振动光谱

用顶部籽晶提拉法,以K2W2O7为助溶剂,生长YbKGd(WO4)2激光晶体.经热重-差热分析,确定晶体熔点为1086℃,相变温度为1021℃.晶体结构分析确定YbKGW(WO4)2晶体由WO6八面体连接而成,WO6八面体是由(WOOW)双氧桥及(WOW)单氧桥构成.晶体粉末样品室温下的红外及拉曼光谱测试,确定WO42-、双氧桥及单氧桥的振动范围,并对其进行了归属.X射线粉末衍射测试,验证所生长的晶体为β-YbKGd(WO4)2.     

微乳液水热法制备钨酸铋光催化剂及性能研究

采用微乳液介导水热法制备Bi2WO6和Fe/Bi2WO6光催化剂,并研究水热反应温度、前驱体pH值、水相与表面活性剂的摩尔比ω值和Fe3+掺杂量对光催化剂结构、形貌和光催化活性等方面的影响.结果表明:合成的Bi2WO6为15～25 nm的纳米球状结构;当前驱体pH=1、水热温度为150℃下合成的Bi2WO6催化剂对亚甲基蓝(MB)的降解率达到93.8%;当ω=27时合成的Bi2WO6对MB光催化降解率达到了97.8%.研究发现当掺入1.03%的Fe3+的Bi2WO6比纯Bi2WO6对MB的降解率提高了2倍,达到90.2%.     

Bi_2WO_6-NiFe_2O_4磁性可见光催化剂的制备及其性能研究

采用水热法制备Bi2WO6-NiFe2O4磁性可见光催化剂。利用X射线衍射(XRD)、紫外-可见漫反射光谱(DRS)、扫描电子显微镜(SEM)和磁学性质测量系统(MPMS)对所合成材料进行分析和表征。最后以罗丹明B(RhB)为目标污染物,考察不同pH值条件下,Bi2WO6-NiFe2O4复合可见光催化剂对污染物的降解效率。结果表明,罗丹明B溶液pH值为5时,Bi2WO6-NiFe2O4具有最大降解效率2 h达98%。Bi2WO6-NiFe2O4在外加磁场下能快速的从溶液中分离。     

pH值和无机盐添加剂对水热合成钨酸铋的影响

在170℃的温和水热条件下,用Na2WO4·2H2O、Bi(NO3)3·5H2O为原料,硝酸钠为添加剂辅助制备了三维(3D)花球状钨酸铋粉体。通过改变添加剂的浓度,发现硝酸钠在诱导花球状钨酸铋的生长和自组装过程中起到关键作用。在合适添加剂浓度的基础上,pH值的变化会对产物的物相和微观形貌有很大的影响。研究结果表明,当pH值≤10.8时,产物为Bi2WO6,当pH值=12.4时,产物转变为Bi3.84W0.16O6.24。当pH值=1.2,硝酸钠浓度为4 mol/L时,获得粉体的比表面积为33.427m2/g。     

Ag和介孔碳改性Bi_2WO_6光催化剂的合成及其可见光下的光催化性能

采用水热法合成了花球状的Bi2WO6和介孔碳CMK-3/Bi2WO6的光催化剂,然后通过光还原得到了Ag负载的Ag/Bi2WO6和Ag-CMK-3/Bi2WO6,制备出可见光下具有高活性的光催化剂。利用紫外-可见漫反射光谱(UV-Vis DRS)、X射线衍射(XRD)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HR-TEM)和扫描电子显微镜(SEM)对制备的样品进行表征,评价样品在可见光照射下降解亚甲基蓝(MB)的光催化活性。并研究了CMK-3和Ag负载在Bi2WO6上都能提高其光催化活性的机制。结果表明:CMK-3或Ag负载在Bi2WO6上都能大幅提高Bi2WO6的光催化活性,Ag-CMK-3/Bi2WO6光催化剂的光催化性能优于Ag/Bi2WO6和CMK-3/Bi2WO6光催化剂。     

Bi_2WO_6催化剂的合成及光催化性能的研究

以Bi(NO3)3·5H2O和Na2WO4·2H2O为原料,采用水热法制备Bi2WO6催化剂,在λ420nm的可见光区降解模拟罗丹明B(RhB)废水,研究前驱物pH值、水热反应温度和时间对Bi2WO6催化性能的影响;通过X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见吸收光谱(UV-Vis)和比表面积(BET)表征,考察前驱物pH值对催化剂晶型、形貌、吸光性和比表面积的影响。结果表明,前驱物pH值为Bi2WO6光催化活性的关键影响因素,且对产物微观结构影响较大。当pH值=4.5时合成的产物光催化活性最佳,反应90 min RhB溶液降解率达到99.90%,经重复使用4次,其光催化效果无明显降低,表明该Bi2WO6是一种有效稳定的可见光催化剂。     

水热合成Bi2WO6/ZnO异质结型光催化剂及其光催化性能

在不同温度下(120～220℃),利用水热法制备了含1wt%、2wt%、4wt%和8wt%Bi2WO6的异质结型Bi2WO6/ZnO复合光催化剂,采用X射线粉末衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、紫外可见漫反射(UV-Vis)吸收光谱及光致发光光谱(PL)等系列手段对所制备的光催化剂进行了表征,并以紫外光(365nm)为光源,酸性橙II为降解对象,进行光催化活性测试,考察了不同Bi2WO6复合量及不同水热温度对ZnO光催化剂反应活性的影响.研究表明,异质结型Bi2WO6/ZnO复合光催化剂的光催化活性明显优于纯ZnO和Bi2WO6.当复合4wt%Bi2WO6水热处理温度为150℃时,所制备的复合光催化剂的光催化活性最佳,为纯ZnO的2.6倍.活性提高的主要原因是形成的Bi2WO6/ZnO异质结能显著降低光生电子和空穴对的复合几率,并改善了异质结型Bi2WO6/ZnO复合光催化剂的表面性能.     

水热法制备K0.5 Bi0.5 TiO3纳米粉体

以Bi(NO3)3·5H2O、Ti(OC4H9)4、KOH为原料,研究和分析了水热条件下纳米K0.5Bi0.5TiO3(KBT)粉体和影响KBT晶体生长与形成的各个影响因素,并利用XRD、TEM、ED等分析方法对所得粉体的晶相、微观形貌、分散性等性质进行了表征.结果表明,反应温度为180℃,保温时间为24h,KOH浓度为4～12mol/L时能制备出纯净的、结晶完整、分散性良好、钙钛矿型的纳米K0.5Bi0.5TiO3晶体,其颗粒尺寸为15～75nm.     

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.