CNTs珠串纳米Cu_2O球的制备及光学性质研究

以Cu(CH3COO)2.H2O和多壁碳纳米管(CNTs)作为前驱体,二甲基甲酰胺(DMF)为溶剂,硼氢化钠(NaBH4)为还原剂,在聚乙烯吡咯烷酮(PVP)援助下得到CNTs珠串纳米Cu2O球。采用XRD、SEM和TEM等手段对CNTs珠串纳米Cu2O球进行了表征。此外,同时也对CNTs珠串纳米Cu2O球复合材料的光学性质进行了紫外-可见吸收光谱分析。     

易于微孔道填充的纳米CuO的制备

分别采用直接沉淀法和快速沉淀法成功地制备了易于微孔道填充的纳米Cu O粉末。直接沉淀法的铜源是无水Cu SO4,沉淀剂是Na2CO3;快速沉淀法的铜源是Cu(CH3COO)2·H2O,沉淀剂是Na OH。通过XRD、SEM、TEM和SAED等分析手段表征产物的晶体结构、微观形貌及晶粒尺寸。结果表明,直接沉淀法的陈化时间对制备样品形貌和结构有影响。当前躯体陈化时间为3 h时,直接沉淀法制备的Cu O纳米颗粒平均粒径约为25 nm;快速沉淀法制备的Cu O纳米颗粒平均粒径约为6 nm。与直接沉淀法相比,快速沉淀法制备的纳米Cu O粒径更小、颗粒分散更均匀。     

离子液体辅助合成BiOBr微球和纳米片及其光催化性能

使用混合溶剂热法,以1-己基-3-甲基咪唑溴盐离子液体([Hmim]Br)和Bi(NO3)3·5H2O为反应物,乙二醇水溶液为溶剂,制备了BiOBr微球和纳米片。利用X射线衍射(XRD)、扫描电镜(SEM)、紫外可见漫反射(UV-Vis)以及N2吸附-脱附等手段对其进行了物相和结构的表征。在可见光照射下,以罗丹明B(RhB)为目标污染物,研究了离子液体存在下,溶剂组成对BiOBr光催化活性的影响。结果表明,当乙二醇与水的比例为3∶1~1∶1时所制备的BiOBr纳米片具有最高的光催化活性;同时,BiOBr纳米片光催化剂稳定性良好,循环使用8次后光催化活性基本稳定。     

Cu_2O/TiO_2复合光催化材料的合成及其对2,4-二氯酚降解性能的研究

采用原位水解的方法制备得到Cu2O/TiO2复合光催化材料。利用扫描电子显微镜对该复合物的形貌进行表征,研究了该复合物在可见光和紫外光下对2,4-二氯酚的光催化降解性能,和单一的Cu2O的光催化活性进行对比。研究表明,可见光下,Cu2O/TiO28h对2,4-二氯酚的降解效率可以达到92.37%;紫外光下,Cu2O/TiO23h对2,4-二氯酚的降解效率可以达到68.6%,其光催化活性优于单一的Cu2O纳米颗粒。     

纳米TiO2光催化剂的结构调控及其光催化活性研究

以酞酸丁酯和冰醋酸分别为前驱物和酸催化剂,采用溶胶 凝胶法制备了纳米 TiO2 粉体, 并且通过改变水体溶液中酞酸丁酯,醋酸和水的摩尔比来调控纳米TiO2 粉体的大小以及光催化活性;探讨在溶胶 凝胶法制备过程中在水溶液中添加表面活性剂十二烷基苯磺酸钠 ( DBS ) 和共溶剂无水乙醇(CH3CH2OH)来调控TiO2 粉体以及光催化活性。用X射线衍射和透射电子显微镜等手段对不同条件制备的纳米粉体的微观结构进行了表征,并且以甲基橙染料的降解为模型反应,考察了不同制备条件下的催化剂的光催化活性,而且对纳米粉体结构和光催化性能之间的关系进行了讨论。     

ZnMn2O4微/纳米纤维的制备及其性能的研究

以聚乙烯吡咯烷酮(PVP)为络合剂与醋酸锌〔Zn(CH3COO)2〕和乙酸锰(Mn(CH3COO)2)反应制得前驱体溶液,用静电纺丝法制备了PVP/Zn(CH3COO)2/Mn(CH3COO)2复合纳米纤维,经煅烧得到具有微孔结构的Mn掺杂ZnO微/纳米纤维。对所制备纤维分别采用差热-热重分析(TG-DTA)、红外光谱(IR)、X射线衍射(XRD)、扫描电镜(SEM)等手段进行了表征。结果表明:PVP/Zn(CH3COO)2/Mn(CH3COO)2纤维表面光滑,直径约300～700nm,经煅烧后,可得到Mn掺杂ZnO微/纳米纤维,XRD测试表明煅烧后的无机纳米纤维呈ZnMn2O4晶相。     

化学溶液沉积法La2CuMnO6缓冲层薄膜的制备与结构表征

根据镧、铜及锰盐在不同溶剂中的溶解性,选择合适的溶剂及镧、铜及锰盐为前驱体,配制成前驱溶液进行润湿性、稳定性及不同衬底热处理实验,成功筛选出制备La2CuMnO6(LCMO)缓冲层薄膜的前驱体,利用X射线衍射(XRD)和原子力显微镜(AFM)对化学溶液沉积法(CSD)合成的La2CuMnO6薄膜的相组成和形貌结构进行了表征。结果表明,选择合适的前驱体(La(CH3COO)3·1.5H2O、Cu(CH3COO)2·1.0H2O、Mn(CH3COO)2·4.0H2O)及SrTiO3(STO)(100)衬底,在1000℃、保温时间3h、空气气氛及总离子浓度为1.0mol/L工艺条件下制备的La2CuMnO6薄膜具有很好的c轴织构,薄膜表面较平整、均匀、无裂纹、无孔洞,分布均匀且排列致密,完全满足缓冲层对薄膜的要求。     

静电纺丝法制备Fe3+/TiO2纳米纤维及表征

以聚乙烯吡咯烷酮(PVP)为纤维模板,钛酸四丁酯(Ti[O(CH2)3CH3]4)和Fe3+为前驱体,乙醇为溶剂,醋酸为催化剂,采用静电纺丝法制备不同含铁量的复合纳米纤维Fe3+/TiO2,经500℃煅烧得到以锐钛矿为主的Fe3+/TiO2纳米纤维。采用扫描电子显微镜(SEM)和X射线衍射仪(XRD)分别表征了Fe3+/TiO2纳米纤维的形貌与晶态,计算了样品的晶粒尺寸和锐钛矿所占的比例,并比较了5%Fe3+/TiO2纳米纤维、5%Fe3+/TiO2粉体以及纯TiO2纳米纤维三者光催化降解亚甲基蓝(MB)的效果。研究表明:由静电纺丝法制备的5%Fe3+/TiO2纳米纤维的光催化降解效果比相同含铁量的粉体的降解效果好,TiO2纳米纤维比5%Fe3+/TiO2纳米纤维的光催化活性高。     

Cu_2ZnSnS_4纳米晶及其薄膜的制备

以乙酰丙酮铜(Cu(AcAc)2)、乙酸锌(Zn(CH3COO)2·2H2O)、氯化亚锡(SnCl2·2H2O)、升华硫(S粉)和十二硫醇为原料,用热注射法合成了Cu2ZnSnS4(CZTS)纳米晶。再将Cu2ZnSnS4纳米晶制成胶体墨水,用旋涂法制备出Cu2ZnSnS4薄膜。用X射线衍射(XRD)仪、拉曼光谱(RS)仪、透射电镜(TEM)、扫描电镜(SEM)、X射线能量色散谱仪(EDS)和紫外-可见光谱(UV-Vis)分光光度计对CZTS纳米晶及薄膜的晶体结构、微观形貌、化学组成及光学性能进行表征,研究了注射温度对纳米晶结构、形貌、晶粒大小以及化学组成的影响以及热处理时间对Cu2ZnSnS4薄膜结构、形貌、化学组成和光学性能的影响。结果表明,在注射温度为180℃时合成的CZTS纳米晶为锌黄锡矿结构,平均粒径为18 nm。在500℃热处理2 h所制备出的薄膜,在可见光范围内其吸收系数高达104cm-1,禁带宽度为1.45 eV。     

NiO-TiO2同轴纳米纤维的制备及光催化

以PVP/Ti(OC4H9)4溶胶为壳层,以PVP/Ni(CH2COO)2·4H2O溶胶为核层,采用同轴静电纺丝法制备了核壳结构Ti(OC4H9)4/Ni(CH3COO)2·4H2O PVP纤维;用程序升温法,在550℃下烧结6 h,制备了NiO-TiO2同轴纳米纤维.采用X射线衍射(XRD)、扫描电子显微镜(SEM)...     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

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...     

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.……     

Roman iron and steel: A review

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.     

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 ...