纳米TiO2薄膜的制备及其光催化性能研究

采用溶胶-凝胶(Sol-gel)法在玻璃衬底上制备了纳米TiO2薄膜.采用X射线衍射仪(XRD)、紫外可见一光谱(UV/vis)和原子力显微镜(AFM)对纳米TiO2进行表征.结果表明,经300～700℃退火得到的TiO2粉体呈锐钛矿相,经800℃退火得到了锐钛矿相与金红石相的混合晶相,经900℃退火完全转化为金红石相.薄膜表面粒子分布均匀,表面平均粗糙度为1.54nm,该薄膜具有较高的光催化活性,可直接用于光催化降解有机物等领域,具有广阔的应用前景.     

纳米TiO2薄膜的低温制备与光谱特性研究

以钛酸丁酯为原料,采用改进溶胶-凝胶法,通过浸渍-提拉工艺在低温条件下制备了锐钛矿纳米TiO2薄膜。利用X射线衍射、紫外-可见光吸收光谱、傅里叶变换红外光谱对所制备的TiO2薄膜的晶型结构和光谱特性进行了分析,并利用紫外光照降解亚甲基蓝溶液来评价所制备薄膜的光催化活性。结果表明:经过陈化和水浴处理后,钛酸丁酯完全水解,所得TiO2薄膜为锐钛矿结构,对紫外光表现出较强的吸收特性。低温水浴处理有利于提高薄膜的光催化活性。     

纳米二氧化钛的晶型转变及光催化性能研究

采用溶胶-凝胶法制得稳定的TiO2透明溶胶．凝胶经焙烧制备了纳米TiO2粉体,利用FT-IR、XRD和原子力显微镜(AFM)技术对其进行了结构和形貌表征,考察了其对水杨酸的光催化活性。研究结果表明,醇胺不同的加入量,对TiO2从锐钛矿转变为金红石型的晶相转变温度(600～800℃)有很大影响．FT-IR谱的423cm^-1处吸收峰为金红石型TiO2的特征Ti-O键振动峰,采用310nm的紫外光波长照射时锐钛矿型TiO2粉体具有较高的光催化活性。     

纳米二氧化钛粉体晶相控制实验研究

在水解－沉淀法制备纳米TiO2粉体的过程中，使用不同的沉淀剂获得了晶相不同的纳米TiO2粉体，使用混合沉淀剂，通过控制沉淀剂的比例，制备了晶相组成（金红石与锐钛矿比例）不同的纳米TiO2多晶粉体，采用相同的粉体制备工艺，不同的后续处理工艺，探讨了锐钛矿向金红石转变的相变温度，经分析研究后认为，水解－沉淀法制备的纳米粉体中的锐钛矿向金红石红转变的温度为500－800℃，完全转变的温度在800℃以上；纳米TiO2多晶粉体的晶相组成不仅与沉淀剂的种类，混合沉淀剂中沉淀剂的比例和粉体的煅烧温度有关，而且与粉体的后续处理工艺和粉体表面界面相的稳定性有关。     

FePc敏化锐钛矿型TiO2的低温制备及性能研究

采用溶胶-凝胶法在低温(50～80℃)下制备得到铁酞菁(FePc)染料敏化的TiO2粉体.利用X射线衍射、红外光谱、光电子能谱、紫外-可见光漫反射光谱对光催化剂的晶相结构、吸收光谱特征进行了表征,结果表明,所制备的复合粉体中TiO2为锐钛矿型,且晶粒细小;FePc敏化的TiO2在可见光区域的吸收有所增强.光催化氧化实验表明,经FePc敏化的锐钛矿型TiO2粉体,在普通日光灯下对甲基橙具有良好的光催化活性.     

钠离子对TiO_2薄膜结构及其光催化活性的影响

采用溶胶-凝胶浸渍提拉法在不同玻璃基板上制备TiO2薄膜,并通过降解浸渍在薄膜表面的甲基蓝来评价其光催化活性。利用X射线衍射(XRD)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱等研究了晶型、表面元素分析和光吸收性能。并采用平行电极法测定TiO2薄膜的光电流,研究了薄膜表面载流子的复合情况。结果表明,薄膜的催化性能主要与基板热扩散到薄膜中的Na+和晶相相关。Na+抑制锐钛矿相TiO2的形成,并且在一定条件下促进由锐钛矿向金红石相的转变。Na+的扩散对TiO2晶粒尺寸影响不大。重要的是,扩散至薄膜的Na+不仅影响TiO2薄膜的晶相转变,而且成为光生电子与空穴的复合中心,同时影响其光催化活性。     

二氧化钛纳米晶的制备及光催化活性研究

本文用溶胶—凝胶法制备了不同晶相的TiO2纳米晶，将其负载于镍网上，以苯酚的降解为模型反应，研究对比了不同晶相TiO2纳米晶的光催化活性。结果表明，纯锐钛矿相的TiO2纳米晶的降解能力要强于锐钛矿与金红石混合相的TiO2纳米晶。     

Fe、S共掺杂纳米TiO2的制备及性能研究

采用溶胶-凝胶法,以硫脲和三氯化铁为掺杂剂,制备了Fe-TiO2、S-TiO2和S-Fe-TiO2纳米光催化剂.通过XRD、SEM等方法对掺杂纳米TiO2进行了表征,以甲基橙为模型化合物对纳米TiO2粉体的光催化活性进行了评价.结果表明;纯TiO2、掺Fe-TiO2粉体全部为锐钛矿相,S-TiO2粉体中金红石相占8.1%,S-Fe-TiO2粉体中金红石相占26.9%.S和Fe、S共掺杂引起金红石相变温度的降低.掺Fe的纳米TiO2粉体粒子团聚少,分散要均匀,掺S和Fe、S共掺的TiO2粉体颗粒团聚现象较严重.S-TiO2和Fe-TiO2光催化荆在紫外光和日光灯下光催化活性都较好,而Fe-S-TiO2光催化活性没有提高.     

罗丹明B敏化锐钛矿型TiO2的低温制备及性能

采用溶胶-凝胶法在低温(60～80℃)下制备得到罗丹明B染料敏化的锐钛矿型TiO2粉体.利用X射线衍射、红外光谱、荧光光谱、紫外-可见光吸收光谱、漫反射光谱对光催化剂的晶相结构、吸收光谱特征进行了表征,结果表明:罗丹明B与TiO2发生了相互作用,罗丹明B敏化的TiO2在可见光区域的吸收增强.光催化氧化实验表明,经罗丹明B敏化的锐钛矿型TiO2粉体,在普通日光灯下对甲基橙具有良好的光催化活性.     

Eu3+和Sm3+共掺杂TiO2光催化剂的协同效应

采用溶胶-凝胶法制备了纯TiO2和Eu3+/Sm3+共掺杂TiO2复合粉体,采用XRD,DRS和SEM等技术进行表征,以亚甲基蓝(methylene blue,MB)的光催化降解为目标反应,评价了其光催化活性,探讨了Eu3+/Sm3+共掺杂对TiO2粉体光催化的影响机制.结果表明,Eu3+/Sm3+共掺杂可以显著提高TiO2粉体光催化活性,Eu3+/Sm3+共掺杂在TiO2粉体中产生协同作用,可以抑制TiO2由锐钛矿相向金红石相转变,使TiO2的粒径减小.Eu3+/Sm3+共掺杂增大了TiO2粉体的晶格畸变,使TiO2粉体吸收带边蓝移.当Eu3+/Sm3+的掺杂量分别为0.05%和0.1%,TiO2光催化活性最高,光催化降解率达到84.8%.     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

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