表面活性剂对纳米氧化锌形貌和发光性能的影响

以二水合乙酸锌和氢氧化钠为原料,分别以表面活性剂十六烷基三甲基溴化铵(CTAB)和聚乙烯吡咯烷酮(PVP)为结构导向剂,采用简单的水热法制备了不同形貌的纳米氧化锌。研究了两种表面活性剂对纳米氧化锌形貌和光致发光性能的影响,并探讨了表面活性剂的作用机理。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和室温光致发光光谱(PL)等测试方法对样品的结构、形貌和发光性能进行了表征。结果表明:添加了表面活性剂后,样品形貌和尺寸都更加均匀,紫外发射峰强度相对增加。     

芳纶表面氧化锌纳米棒的制备及表征

以硝酸锌、六亚甲基四胺为原料,通过低温水浴方法在芳纶Ⅲ表面实现氧化锌纳米棒的修饰。采用X射线衍射仪、扫描电子显微镜、能量色散X射线谱仪、紫外分光光度计和热失重仪等测试手段对所制备的样品进行了表征。结果表明,芳纶Ⅲ表面生长的氧化锌纳米棒为六方纤锌矿相结构,并且择优取向生长。借助于氧化锌纳米棒吸收紫外线的能力和耐高温的特性,氧化锌纳米棒修饰后的芳纶Ⅲ具有良好的抗紫外性和优异的热稳定性。     

醇-水体系无表面活性剂纳米ZnO的制备及表征

以乙酸锌为前驱物,乙醇、正丙醇和正丁醇为溶剂,不加入表面活性剂,通过改变反应体系中醇水体积比、pH值、前驱物浓度,在反应温度80℃、反应时间30 min的条件下,制备得到不同尺寸和形貌的纳米氧化锌粒子.通过透射电子显微镜(TEM)、X射线衍射和紫外-可见吸收光谱等方法对纳米氧化锌进行了表征.结果表明:所合成的纳米氧化锌样品在350～365 nm范围内具有较为明显的吸收峰,减小醇水体积比、减弱溶剂极性、增加前驱物乙酸锌浓度,均可以导致纳米氧化锌粒子尺寸变大、团聚加重,前驱物溶液pH值的改变对纳米氧化锌的吸收峰影响不大.     

表面活性剂辅助水热合成氧化锌纳米棒

以碱式碳酸锌为前驱体, 十六烷基三甲基溴化铵为表面活性剂, 在乙醇-水体系中水热反应制备了直径在10nm以下的氧化锌纳米棒. 用XRD、TEM、SAED等分析手段对制备的粉体进行了表征, 并对粉体的室温光致发光性能进行了测试. 结果表明, 合成的氧化锌纳米棒结晶良好, 沿[001]方向生长, 具有良好的近紫外发光性能. 同时对氧化锌纳米棒的生长机制进行了探讨.     

表面改性方式对纳米氧化锌紫外吸收性能影响研究

纳米氧化锌是一种重要的无机紫外吸收剂,在应用时需要对其进行表面改性和分散,本文研究了不同的改性方式对纳米氧化锌紫外吸收性能的影响,分析研究了其不同的改性机理.结果表明原位改性是一种较好的改性方式,但对纳米氧化锌的外观形貌产生了影响,主要原因是聚乙二醇作为模板剂和表面活性剂影响了其前驱体氢氧化锌的形貌,而纳米氧化锌粉体表面改性是通过聚乙二醇的空间位阻作用使纳米氧化锌分散程度提高.使用同一种改性剂对纳米氧化锌原位改性和对纳米氧化锌粉体改性,对其紫外吸收性能没有大的影响.     

化学水浴法制备CuS纳米花状球及其光学性能研究

利用化学水浴法,以表面活性剂十二烷基苯磺酸钠(SDBS)为辅助,在100℃反应4h合成了CuS纳米花状球。用粉末X射线衍射仪(XRD)、X射线能谱仪(EDX)、场发射扫描电子显微镜(FESEM)、紫外-可见分光光度计(UV-Vis)以及荧光光谱仪(PL)等手段对产物进行了表征。研究表明,产物结晶性良好,产率高,形貌规整且粒径分布均匀,纳米花状球的平均直径为350nm。产物在370nm波长光的激发下,于可见光区域486nm处产生强的荧光发射峰,发生了明显的蓝移。通过对CuS纳米花状球形成机理和实验条件进行系统探讨,提出了3步反应机理,同时发现表面活性剂SDBS对产物的形貌和尺寸起着关键作用。     

一维纳米氧化锌的溶剂热法制备及其光致发光性能

以乙二胺为介质，利用溶剂热法合成出一维结构的纳米氧化锌，并通过透射电镜（TEM）、X射线衍射（XRD）等对产物的形貌和结构进行了表征。在反应过程中，纳米氧化锌通过“溶解-结晶”机制形成。实验制得纳米氧化锌的紫外-可见光谱体现出其纳米材料的小尺寸效应，在波长325nm处显示较强的激子吸收，与体相材料相比产生明显蓝移；荧光...     

瓶状和棒形的纳米ZnO光催化降解甲基橙的研究

以硝酸锌,醋酸钠为原料,聚乙二醇-10000为表面活性剂,采用溶剂热法合成了瓶状和棒形的纳米ZnO,并用X射线衍射仪(XRD)、透射电镜(TEM)、紫外-可见分光光度计时其进行了表征,结果显示合成的纳米ZnO属于六方纤锌矿的晶体结构,对200～380nm波长范围的紫外光有较强的吸收性能.并以纳米ZnO作为光催化剂对甲基橙进行了光降解实验,研究了催化剂用量、甲基橙初始浓度及电解质(SO2-4、Cl-)等对甲基橙降解率的影响.     

Ag_2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物,在甲苯-水两相界面处合成了Ag_2S纳米粒子。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)和广角X射线衍射(WAXD)等方法对Ag_2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明,通过改变甲苯-水两相界面反应体系的条件,可以得到粒子尺寸窄分布的Ag_2S纳米粒子;WAXD测定表明所合成的Ag_2S纳米粒子具有单斜结构。     

Ag2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物，在甲苯一水两相界面处合成了Ag2S纳米粒子。采用紫外一可见吸收光谱（U弘Vis）、透射电子显微镜（TEM）和广角X射线衍射（WAXD）等方法对Ag2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明，通过改变甲苯一水两相界面反应体系的条件，可以得到粒子尺寸窄分布的Ag2...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

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.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.