钬掺杂对SrAl2O4:Eu2+,Dy3+发光性能的影响

首次研究了Ho3+掺杂对SrAl2O4:Eu2+,Dy3+发光性能的影响.采用燃烧合成方法,在600℃条件下,合成Ho3+掺杂的SrAl2O4:Eu2+,Dy3+新型长余辉光致发光材料.X射线衍射分析结果表明,合成的样品为单相SrAl2O4单斜晶系磷石英结构.光致发光光谱测量显示,合成样品的发射光谱是连续宽带谱,峰值位于510nm左右,激发光谱是单峰且峰值位于356nm的连续宽带谱.利用单光子计数系统测量了材料的余辉衰减曲线,结果显示Ho3+的适量掺杂可以明显提高铝酸锶的初始发光亮度.当Ho3+的掺入摩尔比例为0.005时,初始亮度是不掺杂Ho3+时的两倍多.对初始亮度增强的机理做了初步的探讨.     

不同结构稀土掺杂铝酸锶的合成与发光性能研究

采用燃烧法成功合成了稀土掺杂铝酸锶长余辉发光材料.XRD结果表明,当铝锶n(Al)∶n(Sr)=2时,发光基质中只存在SrAl2O4相结构.随着Al∶Sr比值的增大,出现新相Sr4Al14O25.当Al∶Sr比值增大到4时, SrAl12O19相开始形成.而Al∶Sr比值增大到12时,全部为SrAl12O19相.光致发光测量结果表明,发光样品SrAl2O4∶Eu2 ,Dy3 发射谱峰值位于519nm,而发光样品SrAl12O19∶Eu2 ,Dy3 的发射峰位于512nm.余辉检测结果表明,不同结构铝酸锶发光样品的衰减都是由初始的快衰减过程和其后的慢衰减过程组成,但是不同结构铝酸锶发光样品的初始亮度和发光衰减快慢不同.     

电子束还原SrAl_2O_4:(Eu~(2+),Dy~(3+))长余辉材料的力致发光研究

通过高温烧结和电子束还原法制备了SrAl2O4:(Eu2+,Dy3+)长余辉发光材料,并利用球磨获得了SrAl2O4:(Eu2+,Dy3+)长余辉发光粉。通过把发光粉与环氧树脂混合制备了含有SrAl2O4:(Eu2+,Dy3+)长余辉发光粉的夜光胶,利用丝网印刷涂敷技术及热处理在石英玻璃上涂敷了厚度为1000 nm量级的SrAl2O4:(Eu2+,Dy3+)长余辉发光膜。通过小球下落冲击法和一套自制的基于一个雪崩二极管和皮安表的测试装置研究了这种长余辉发光膜的力致发光特性。研究发现,电子束还原法制备的SrAl2O4:(Eu2+,Dy3+)长余辉发光膜具有很好的力致发光特性,具有高达1.25的信背比和很高的信噪比。力致发光强度与小球下落前的初始高度即冲击发生前小球的动能成指数关系,光谱特性及衰减特性与长余辉发光相似。上述结果表明,力致发光是小球冲击能传递给电子并引起电子进入陷阱能级然后释放引起的。     

SrAl2 O4:Eu2+,Dy3+/TPE发光材料的制备及其光学性能

SrAl2O4:Eu2+,Dy3+/TPE是一种新型发光材料,用其制备的电缆护套在黑暗条件下可快速检测电缆状态.本研究先将稀土铝酸锶发光材料(SrAl2O4:Eu2+,Dy3+)与热塑性弹性体(thermoplastic elastomer,TPE)进行混合,再通过双螺杆挤出机共混制备了SrAl2O4:Eu2+,Dy3+含量分别为5％、7％、10％、15％的发光材料.借助荧光光谱仪、余辉亮度测试仪等表征手段探讨了不同SrAl2O4:Eu2+,Dy3+含量发光材料的发光性能.对SrAl2O4:Eu2+,Dy3+/TPE发光材料在水中浸泡后的pH值进行测定,进一步考察了发光材料的耐水性.研究结果表明:发光材料在TPE中分散较为均匀但出现少量团聚现象;发光材料的晶体结构和光谱性质没有因制作工艺而发生破坏或改变,其光学性能得到保证;发光材料的耐水性能较好,随着SrAl2 O4:Eu2+,Dy3+含量的增加,余辉初始亮度有所提高.余辉时长10h以上,使电缆检测更加便利.     

碱土金属长余辉材料的耐酸碱性研究

分别对发光性能最好的铝酸盐基质长余辉材料SrAl2O4∶Eu2+,Dy3+与硅酸盐基质长余辉材料Sr2MgSi2O7∶Eu2+,Dy3+进行酸、碱处理(以HNO3和NaOH为例),研究其耐酸碱性能。XRD、SEM、激发光谱、发射光谱以及余辉特性测试的结果表明:SrAl2O4∶Eu2+,Dy3+及Sr2MgSi2O7∶Eu2+,Dy3+经酸、碱处理后物相发生了部分改变,其激发与发射光谱的强度随着酸碱度的增大而降低,但峰形与峰位没有改变;SrAl2O4∶Eu2+,Dy3+经酸碱处理后表面变得更不平整,棱角变得不明显;SrAl2O4∶Eu2+,Dy3+经酸处理后的初始亮度为未处理时的39.2%,经碱处理后的初始亮度为未处理时的14.0%;Sr2MgSi2O7∶Eu2+,Dy3+经酸碱处理后晶体的结构、形貌、表面及余辉衰减情况基本无变化。     

溶胶-凝胶法制备铝酸锶发光材料

用溶胶 凝胶法合成制备铝酸锶 (SrAl2 O4:Eu2 + (SE) ,SrAl2 O4:Eu2 + ,Dy3+ (SED) )体系长余辉发光材料 ,用X射线粉晶衍射仪 (XRD)、荧光光度计等对制备产物进行了分析测试。用溶胶 凝胶法 (Sol gel)制备铝酸锶长余辉体的最佳温度为 1 2 0 0～ 1 2 5 0℃。     

微波等离子体合成铝酸盐长余辉发光材料的工艺优化

采用微波等离子体固相反应法(MWPM)合成SrAl2O4:Eu2 ,Dy3 稀土长余辉发光材料,运用正交实验方法进行了工艺优化实验.研究了工艺参数对产物发光性能的影响规律.结果表明影响材料发光性能最主要的工艺因素是放电气体的压力,其次是加热时间和微波功率的升降速率,而微波功率的影响较小.材料的发光性能随气体压力的增加,表现出先增强后减弱的变化趋势;同时随升降功率速率的减慢和保温时间的增加而逐渐提高.XRD及SEM分析表明在最优化的工艺条件下制备的产物为单斜晶系的SrAl2O4,粒径尺寸在5～15μm之间,晶粒发育较好,基质结晶完整;光谱分析显示材料的激发光谱和发射光谱都为宽带谱.主峰分别位于326nm和520nm处;余辉性能测试表明材料的1h余辉亮度可达24.36mcd/m2,材料发光性能优良.     

燃烧法合成超细SrAl_2O_4:Eu~(2+),Dy~(3+)长余辉发光材料

利用氧化还原反应燃烧过程合成SrAl2O4:Eu2+,Dy3+长余辉发光材料,采用荧光光谱、X射线衍射、扫描电镜、余辉测试等多种测试手段研究产物的性质,并从多方面与高温固相法合进行对比。结果表明:燃烧法合成的产物为单斜晶系的SrAl2O4,结晶干净完整,晶粒尺寸在0.3～1μm之间;光谱分析显示燃烧法合成材料发射波长为514 nm。相比高温固相法,燃烧法在工艺上具有低温、快速、节能的优点,所得产物易于粉碎,晶粒大大减小。     

自蔓延低温合成SrAl2O4∶Eu2+,Dy3+及其粒径控制与发光性能

本文采用自蔓延低温(600℃)方法合成了铝酸盐长余辉材料SrAl2O4∶Eu2+,Dy3+;通过添加聚乙二醇(PEG)有效控制材料的粒径,并采用XRD,SEM,PL等测试方法对粒径、形貌、发光性能等进行了研究。随着PEG量的增加,材料粒径呈减小趋势;未添加PEG时,材料粒径范围在0.2～1.2μm;当PEG的量为0.4%时,材料初始亮度最高,为19110mcd/m2,余辉衰减最慢,材料粒径分布在0.1～0.8μm;当PEG量为0.6%时,粒径最小,粒径范围在0.1～0.5μm。添加PEG后材料的发光亮度有所提高,而余辉衰减变化不明显。实验结果表明:自蔓延低温合成SrAl2O4∶Eu2+,Dy3+时,通过添加PEG能有效控制合成材料的粒径,借助于PL测试手段以及余辉衰减实验,激发、发射光谱测定所得的检测波长分别为516nm、363nm,合成了粒径细小且发光性能优良的发光材料。     

PMMA/硅铝包覆铝酸锶复合发光材料的制备和发光性能

采用原位乳液聚合法制备了聚甲基丙烯酸甲酯(PMMA)/硅铝包覆(SrAl2O4:Eu,Dy)复合发光材料。通过傅立叶变换红外光谱(FT-IR)和热失重(TGA)测定,研究了复合发光材料的结构,结果表明,复合发光材料中聚合物分子与硅铝包覆(SrAl2O4:Eu,Dy)之间是通过键合的方式结合;通过荧光光谱和发光亮度测试,研究了复合发光材料的发光特性和余辉性能,结果表明,在硅铝包覆(SrAl2O4:Eu,Dy)表面共价结合上PMMA后仍能保持SrAl2O4:Eu,Dy原有的发光性能。     

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.     

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.     

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.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.