掺铒碲酸盐玻璃光谱性质的J-O计算

研究了掺Er3+碲酸盐玻璃的吸收和荧光光谱性质;应用Judd-Ofelt理论计算了碲酸盐玻璃中Er3+离子的强度参数Ω(Ω2=4.79 × 10-20cm2,Ω4=1.52×10-20cm2,Ω6=0.66×10-20cm2),计算了离子的自发跃迁几率,荧光分支比;应用McCumber理论计算了Er3+的受激发射截面(σe=10.40 × 10-21cm2)、Er3+离子4I13/2→4I15/2发射谱的荧光半高宽(FWHM=65.5nm)及各能级的荧光寿命(4I13/2能级τrad=3.99ms);比较了不同基质玻璃中Er3+离子的光谱特性,结果表明掺铒碲酸盐玻璃更适合于掺Er3+光纤放大器实现宽带和高增益放大.     

掺铒碲酸盐玻璃的热力学稳定性和光谱性质的研究

分析了掺Er³⁺碲酸盐玻璃的热力学稳定性能,研究了掺Er3+碲酸盐玻璃的吸收和荧光光谱性质;应用Judd-Ofelt理论计算了碲酸盐玻璃中Er3+离子的强度参数Ω(Ω₂=4.79×10^-20cm², Ω₄=1.52×10^-20cm²,Ω₆=0.66×10^-20_cm2),计算了离子的自发跃迁几率,荧光分支比;应用McCumber理论计算了Er3+的受激发射截面(σ_e=10.40×10^-21cm²)、Er³⁺离子⁴I_13/2→⁴I_15/2 发射谱的荧光半高宽(FWHM=65.5nm)及各能级的荧光寿命(⁴I_13/2能级为τ_rad=3.99ms);比较了不同基质玻璃中Er3+离子的光谱特性,结果表明掺铒碲酸盐玻璃更适合于掺Er³⁺光纤放大器实现宽带和高增益放大.     

掺铒碲基单模光纤的制备及其放大自发辐射光谱

制备了一种新型的可应用于1．5μm通讯窗口宽带放大自发辐射光源的掺铒碲酸盐玻璃单模光纤（EDTF），并分析了其热学性质和光谱特性、该玻璃显示了良好的热稳定性（△T〉150℃）和匹配的热膨胀系数．采用自制EDTF短光纤，组装了超荧光单程反向结构光源（SPB），利用波长为980nm的半导体激光器抽运掺Er^3＋的碲酸盐短光纤，可在1450-1650nm范围获得宽带宽的铒离子放大自发辐射光谱（ASE）．研究了光纤长度，泵浦功率等对放大自发辐射光谱的影响．研究结果显示，该碲酸盐玻璃是一种适用于宽带放大自发辐射光源的基质材料．     

碱金属和碱土金属对掺Tm3+碲酸盐玻璃光谱性质的影响

研究了碱金属和碱土金属离子修饰的掺铥碲酸盐玻璃的光谱性质,讨论了碱金属和碱土金属对掺铥碲酸盐玻璃J-O强度参数、1.46μm荧光发射强度、荧光半高宽、受激发射截面等光谱性质的影响,并与一些传统氧化物玻璃进行了比较.研究表明碱金属Li 和碱土金属Ba2 掺碲酸盐玻璃更适宜用作掺铥光放大器基质.含Li 的碲酸盐玻璃展现出7.90×10-21cm2的高发射截面;含Ba2 碲酸盐玻璃具有7.55×10-21cm2的高发射截面、103nm的荧光半高宽.     

1.55μm光纤放大器用掺Er3+碲酸盐玻璃光谱性能研究

制备了TeO2-BaO(Li2O,Na2O)-La2O3掺铒碲酸盐玻璃系统,测量玻璃的密度、折射率和DSC曲线,以及玻璃的吸收光谱和荧光光谱.由测得的密度和折射率等参数,应用Judd-Ofelt理论和McCumber理论,计算出碲酸盐玻璃的各光学性能参数与受激发射截面.且从测得热稳定性能较好的TBLE3荧光发射谱图中得到该碲酸盐玻璃荧光半高宽(FWHM)为～60nm,σepeak×FHWM值高达～600,明显大于掺铒硅酸盐玻璃和磷酸盐玻璃,表明该种碲酸盐玻璃是光纤发大器用的理想基质材料.     

掺铒铋酸盐玻璃光谱性质的混合形成体效应

测得了Er3+离子在铋酸盐玻璃系列(50～75)Bi2O3-(20～45)B2O3-5Na2O,70Bi2O3-(17～25)B2O3-xZrF4-5Na2O,70Bi2O3-(0～25)B2O3-(0～25)SiO2-5Na2O中的吸收光谱、荧光光谱及4I13/2能级荧光寿命.提出并研究了Er3+离子光谱性质的混合形成体效应,结果表明Er3+离子在铋酸盐玻璃中通过混合形成体效应可以获得较大的有效线宽(△λeff＝62～80nm)、较高的受激发射截面(σe＝0.76～0.84×10-20cm2)、较宽的荧光半高宽(FWHM＝55～80nm)以及较长的荧光寿命(τm＝1.6～4.3ms),说明掺Er3+铋酸盐玻璃是光纤放大器实现宽带和高增益放大较为理想的基质材料.     

掺铒氧氟碲酸盐玻璃的上转换发光研究

研究了掺铒氧氟碲酸盐玻璃的吸收光谱和上转换发光光谱，分析了Er^3 离子在氧氟碲酸盐玻璃中的上转换发光机理．结果表明：通过975nm的激光二极管(LD)激发，在室温下同时观察到强烈的绿光(524和545nm)和红光(655nm)，分别是由于Er^3 离子^2H11／2→I15／2，^4S3／2→I15／2，和^4F9/2→I15／2跃迁．随PbF2含量增加，绿光的发光强度增加趋势较小，而红光的发光强度增加趋势大于绿光．上转换发光机理主要涉及能量转移和激发态吸收，强烈的绿光和红光激发都是由于双光子吸收过程．     

掺镝的氟锆酸盐玻璃的光谱

测量了氟锆酸盐玻璃中Dy3+离子的吸收光谱和荧光光谱,得到了Dy3+离子的J-O参量Ωt,Ω2=3.29×10 20cm2,Ω4=1.56×10 20cm2,Ω6=2.48×10 20cm2.计算了氟锆酸盐玻璃中Dy3+离子的发射特性,Dy3+离子1.3μm发射的6F11/2(6H9/2)→6H15/2跃迁的发射截面σe=0.62×10-20cm2.研究了Dy3+离子浓度对其荧光强度的影响,当Dy3+离子掺杂浓度(摩尔分数)超过1.5%时,发生了浓度淬灭效应.     

掺铒铋基玻璃的荧光俘获和浓度猝灭效应研究

用高温熔融法制备了系列掺铒铋硼锗酸盐玻璃,测试分析了不同铒离子掺杂浓度下玻璃样品的吸收光谱和荧光光谱.结果显示,掺铒铋硼锗酸盐玻璃中存在着强烈的荧光俘获和浓度猝灭效应.随着铒离子掺杂浓度的增加,1.53 μm波段荧光谱展宽,1 560 nm波长处荧光次峰相对增强.对此用一个等效的四能级模型予以了定性分析.同时,随着铒离子掺杂浓度的增加,4I13/2能级荧光寿命和1.53 μm波段荧光强度呈现出先增加后减小趋势.依据Dexter能量转移理论,计算了该玻璃系统中铒离子发生浓度猝灭的临界距离R0及相互作用参数CEr-Er,并与其它玻璃基质进行了比较.     

10×10InGaAsP/InP阵列波导光栅器件的研制

研制了脊形波导结构的10×10InGaAsP/InP阵列波导光栅器件(AWG),并采用掺铒光纤放大器(EDFA)作宽带光源测量了AWG的近场图以及分光特性。     

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.     

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 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.……     

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.     

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.     

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.