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1.
采用双子型季铵盐类阳离子表面活性剂溴代Gemini1231做模板剂,用溶胶-凝胶(sol-gel)法在室温合成了介孔TiO2材料,用TG-DTA、XRD、N2吸附-脱附、TEM等进行表征.结果表明,用该模板剂合成的介孔TiO2材料,合适的煅烧温度为480℃,其比表面积可达383.8m2/g,最可几孔径为5.8nm,广角XRD测试发现较强的锐钛矿型特征峰,而未发现金红石相特征衍射峰,说明本实验制备的介孔TiO2为稳定锐钛矿型.通过小角X射线衍射分析发现,产物具有规整有序的介孔结构.  相似文献   

2.
采用模板剂法制备了系列NiO-TiO2复合半导体,用N2吸附-脱附、XRD、TPR、TEM和UV-Vis DRS等方法对半导体材料的孔结构、表面构造、能带结构与其吸光特性进行了分析. 结果表明:所制备的NiO-TiO2为介孔结构的纳米管或带,其比表面积超过100m2/g;NiO在TiO2表面分散均匀,并部分形成NiTiO3固熔体;NiO与TiO2间存在明显的复合效应,当NiO含量由2%增加至10%时,其Eg值由3.82eV降至3.49eV,有效地拓展了光响应范围.  相似文献   

3.
氮硫掺杂介孔TiO2薄膜结构及其光催化性能   总被引:1,自引:0,他引:1  
分别以Ti(OBun)4和Pluronic F127为无机前驱体和模板剂, 以硫脲为添加剂, 采用sol-gel法结合蒸发致自组装法(EISA)制备了锐钛矿结构的介孔TiO2薄膜材料.采用SEM、 XPS、N2 吸附-脱吸、XRD和 UV-Vis光谱对其进行了表征. 研究发现, 向前驱体溶液添加硫脲一方面改变了TiO2的介孔结构, 另一方面对介孔TiO2进行了N、S共掺杂. 当溶液中硫脲与Ti(OBun)4的摩尔比为2.5%时, 介孔TiO2的孔径由未掺杂的7.0nm增至12.4nm, 光催化降解甲基橙实验表明其在紫外光区具有最优的光催化活性; 当溶液中硫脲与Ti(OBun)4的摩尔比为5%时, 其吸收边由380nm扩展至520nm, 光催化降解罗丹明B实验表明其在可见光下显示出最优的光催化活性.  相似文献   

4.
以十六烷基三甲基溴化铵为模板, 通过钛酸丁酯与六水氯化镍的固相反应直接合成了镍掺杂的二氧化钛(Ni-TiO2)介孔材料. 用X射线衍射、高分辨透射电镜、N2脱附-吸附、红外、紫外以及拉曼光谱仪等分析技术对材料进行了物相与表面织构表征; 通过电感耦合等离子发射光谱仪对材料的元素组成进行分析; 同时研究了材料对甲基橙的光降解性能. 结果表明, 所得的介孔材料是锐钛矿型, 金属镍已进入了二氧化钛骨架, 镍的含量为3.62wt%; 孔壁是由无定形的晶界与微晶组成, 并伴有结构缺陷和痕量的金属镍氧化物; 其BET比表面积为102.4m2/g, 孔半径分布中心为2.4nm. 在298K下, Ni-TiO2介孔材料对甲基橙溶液的紫外光降解行为遵循准一级动力学反应规律,其反应速率常数比纯TiO2粉体大二倍, 且存在明显的浓度效应.  相似文献   

5.
采用固相反应法制备了 (Mg0.93Ca0.05Zn0.02)(Ti1-xAlx)O3介质陶瓷.研究了Zn-Al共掺杂对0.95MgTiO3-0.05CaTiO3(95MCT)陶瓷介电性能的影响.结果表明:Zn-Al共掺杂的95MCT陶瓷的主晶相为MgTiO3和CaTiO3两相结构,Zn-Al共掺杂可以抑制中间相MgTi2O5的产生,同时,有第二相CaAl2O4出现;Zn-Al共掺杂能有效地降低95MCT陶瓷的烧结温度至1300℃,改善介电性能,并对介电常数温度系数具有调节作用.当 Zn2+掺杂量为0.02mol、Al3+掺杂量为0.02mol时, 在1300℃烧结2.5h获得最佳性能:εr =20.35, tgδ=2.0×106, αc=1.78×106.  相似文献   

6.
表面活性剂辅助水热热分解法制备介孔氧化铝纤维   总被引:3,自引:0,他引:3  
以PEG(Mn=20000)为模板导向剂, 尿素为沉淀剂, 采用水热热分解法制备了纳米介孔结构的氧化铝纤维, 并对其吸附性能进行了研究. 通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、热释重仪(TGA)和N2等温脱附-吸附分析, 考察了介孔氧化铝纤维的相态、结构、形貌、比表面积和介孔特征. 采用选择性催化还原(SCR)烟气脱硝装置对其吸附性能进行了研究. 结果表明:以PEG为模板, 采用简单的水热法就可得到直径(200~300)nm×(8~10)μm的碳酸铝铵纤维; 经900℃煅烧2h得到比表面积为316m2/g、平均孔径为2.5nm的η-Al2O3介孔纤维, 形貌基本不发生变化; SCR烟气脱硝测试显示, 相比商品氧化铝粉末, 合成的氧化铝介孔纤维有着更强的吸附性能, 它的脱硝效率较之商品氧化铝粉末约提高了15%.  相似文献   

7.
以硝酸钙、硫酸钛、磷酸和氨水等为原料, 通过共沉淀水热合成和离子交换法, 制备了钛(Ⅳ)与锌离子共掺杂的羟基磷灰石(Ca10(PO4)6(OH)2, HAp)白色纳米粒子(TiZnHAp). 采用XRD、TEM、EDS、UVVis和ESR测试对样品的结构、形貌、组成、吸光性能以及催化氧化活性进行了表征. 针对大肠杆菌和金黄色葡萄球菌进行了抗菌实验测试, 研究材料在黑暗和室内弱紫外光下的抗菌活性. 结果表明, 钛(Ⅳ)的掺杂没有明显改变HAp晶粒的形态和尺寸, 而钛(Ⅳ)的掺杂能够提高HAp的吸光性能和紫外光催化氧化能力. 相对于ZnHAp和TiHAp颗粒, 在室内弱紫外光下钛(Ⅳ)的光催化分解细菌与锌离子抗菌协同作用使TiZnHAp具有优良的抗菌效果. 同时, 离子溶出测试实验结果表明, TiZnHAp具有长效抗菌性.  相似文献   

8.
以离子交换法获得的可溶性钨酸溶液与TiO2为原料,制备了TiO2-WO3复合光催化材料. 用电化学恒电流放电法表征了材料的储能特性,并结合XRD、TEM、BET、UV-Vis等手段,研究了材料中WO3的晶型和结晶度随热处理温度的变化及其对材料光催化储能效应产生的影响. 在电化学测试中,TiO2-WO3复合材料显示了一定的光催化储能特性. 且WO3的结晶度对材料储能性有一定的影响:WO3为水合态或结晶度很低时,材料几乎没有光催化储能性;随着结晶度的增强,储能性提高;TiO2-WO3的储能性能最高达到0.83×10-3C·mg-1; 结晶度过高,储能性反之降低. 利用材料的光催化储能特性,在黑暗条件下对罗丹明B的降解率为11%,显示了一定的储能降解活性.  相似文献   

9.
为了合成单相以及Yb3+、 Er3+掺杂的六方结构NaYF4,采用微波水热的方法,以稀土硝酸盐、氟化钠、柠檬酸、氢氧化钠、乙酸乙酯和水为原料,合成了六方相NaYF4以及Yb3+、Er3+掺杂的六方相NaYF4 (NaYF4∶Yb3+,Er3+)微米管. 利用XRD、SEM对所得样品的物相和形貌进行了表征. 研究了不同反应条件对产物形貌和物相的影响,并提出了NaYF4微米管的形成机理. 研究发现,采用微波加热的方法可以在较低的温度下快速得到单一六方相的NaYF4. 所制备的Yb3+、 Er3+掺杂NaYF4微米管的上转换发光性能与其体材料类似,具有较高的发光强度.  相似文献   

10.
采用复合表面活性剂CTAB和P123形成的超分子模板为结构导向剂,以工业硫酸氧钛液为钛源,控制溶液pH值及水解条件调控TiOSO4的水解缩聚及与模板剂的自组装速率,钛水解胶粒通过界面作用形成介孔前驱体,脱模后制得二维六方,比表面积为205.7m2/g,平均孔径为3.28nm的锐钛型有序介孔TiO2. 用XRD、HRTEM、SAED及等温N2吸附等对样品进行了表征,初步探讨了介孔的形成过程. 钛水解胶粒和复合模板剂通过界面处的静电和氢键等相互作用,协同形成介孔结构,属协同作用机理.  相似文献   

11.
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   

12.
13.
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   

14.
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   

15.
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   

16.
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   

17.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.  相似文献   

18.
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   

19.
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.  相似文献   

20.
Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.  相似文献   

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