高次谐波开槽潘尼管中的电子轨道研究

利用自洽非线性理论研究了8 mm 3次回旋谐波开槽潘尼管注波互作用。首先,明确地揭示了在高次回旋谐波开槽潘尼管中,电子回旋谐波次数,高频场分布,决定了不同初始相位电子的电子能量分布以及引导中心漂移规律,指出当回旋半径减小,引导中心偏移达到一定程度时,谐振条件被破坏限制了高次谐波潘尼管效率的提高,并提出了通过优化磁场分布提高效率。最后,进一步研究了电子纵向速度离散、偏心和电流大小等因素对互作用效率的影响,表明在实验可达到的电子注质量下,研制实用的高效高次谐波潘尼管是可行的。     

DNP-NMR用263 GHz回旋振荡管高频系统的研究

根据动态核极化核磁共振(DNP-NMR)发展需要,对应用于400 MHz DNP-NMR的263 GHz回旋振荡管高频系统进行研究,通过非线性理论计算程序对其进行分析,给出了工作模式为TE03的高频系统的设计参数。并通过粒子模拟(PIC)软件进行注波互作用计算,结果表明,在工作电压10 kV,注电流0.2 A,电子注速度比为2.0时,设计的高频系统输出功率为460.2 W,效率达到23.1%,约1 GHz的调频率范围,可满足263 GHz整管参数设计要求,从而为DNP-NMR用回旋振荡管的研制打下技术基础。     

同轴结构8mm扩展互作用振荡器的分析研究

为了克服扩展互作用振荡器采用实心电子注输出功率受限制的问题,本文设计了一种新型的同轴毫米波扩展互作用振荡器。采用MAGIC粒子模拟软件分别对高频系统和电子枪进行了数值模拟,分析了聚焦磁场、电子注电流、电压和内导体半径等工作参数对输出功率的影响。根据获得的工作参数的优化值对整管性能进行了模拟分析,给出了电子轴向动量沿轴向的相空间分布图、高频电压时间曲线、幅频特性图和输出波导截面上功率流的时间曲线图。整管模拟结果表明,该器件在8mm波段能产生频谱特性良好、输出功率达14．5kW的微波输出。     

高频离子源的光学设计

ns-200中子发生器采用的是高频离子源,面临着提高离子源的性能,增大引出束流的技术改造问题。为此开展了高频离子源的设计研制工作。高频离子源采用管道式引出结构和三圆筒单透镜聚焦系统。根据设计指标要求和离子光学原理,经过计算和优化,确定了引出系统和聚焦系统的主要参数。采用传输矩阵和束矩阵(σ矩阵)相结合的数值计算方法,运用LEADS软件模拟计算了束流传输过程,模拟计算的结果与理论设计相吻合。在ns-200中子发生器上进行了初步的实验,表明设计的高频离子源束流光学系统是合理的。     

10W/80K高频同轴脉冲管制冷机的实验性能

介绍了一款大冷量高频单级同轴脉冲管制冷机的基本结构、数值模拟和实验性能。其线性压缩机采用Redlich动磁式直线电机驱动,压缩活塞对置布置,使用板弹簧支撑和间隙密封技术,80 K温区工作时的电机效率在83%以上。膨胀机的蓄冷器和脉冲管为同轴型布置,这种结构使冷头与器件之间的耦合非常方便。使用数值软件对制冷机整机和调相部件进行数值模拟,并对模拟结果进行实验验证。对制冷机的运行频率和制冷性能进行实验研究,制冷机在210.3 W输入电功时能获得10 W/80 K的制冷性能,比卡诺效率为12.66%,运行频率为62 Hz,整机重量小于5.5 kg。     

基于高电阻率衬底的Si/SiGe HBT

介绍了一种基于电阻率高达1000Ω·cm的硅衬底的锗硅异质结晶体管的研制.首先根据衬底寄生参数模型分析了衬底对器件高频性能的影响,然后设计了器件的材料与横向结构尺寸,该器件采用掩埋金属自对准技术在3μm工艺线上制备而成,测得其典型直流电流增益为120,BVCEO为9.0V,fT为10.2GHz,fmax为5.3GHz,比同结构尺寸的常规N 衬底Si/SiGe HBT的fT和fmax分别高出3.9GHz和1.5GHz.     

基于金属栅脊加载矩形波导慢波结构的非共振斜注管

提出了一种使用金属栅脊加载矩形波导慢波结构的非共振斜注管。研究了金属栅脊加载矩形波导慢波结构的高频特性,并将其与矩形波导栅慢波结构的高频特性进行对比。设计了一只使用金属栅脊加载矩形波导慢波结构的非共振斜注管和一只使用矩形波导栅慢波结构的非共振斜注管。利用粒子模拟软件对两种非共振斜注管的输出特性进行了仿真,结果表明,相同工作频段内,使用金属栅脊加载矩形波导慢波结构的非共振斜注管具有更高的输出功率和电子效率。     

高频回旋管微波烧结纳米陶瓷研究

在高频回旋管微波烧结系统上进行纳米陶瓷烧结研究,制备出氧化锆单元及二元纳米陶瓷样品,对不同烧结工艺制备出的样品做了密度、硬度测试,利用XRD和扫描电镜分析陶瓷样品晶粒特性,以摸索适宜的烧结工艺.探讨了高频回旋管微波烧结纳米陶瓷的可行性.     

94GHz TE02模回旋管Vlasov模式变换器的设计与模拟

该文研究并设计了一个由Vlasov阶梯型开口辐射器、椭圆面反射器和抛物面反射器组成的TE02模回旋管准光模式变换器。首先采用几何光学研究了阶梯型开口辐射器、椭圆面反射器和抛物面反射器的具体形状,再利用矢量绕射理论分析了其工作过程,最后结合94 GHz TE02模回旋管的具体参数,编写仿真程序详细讨论了工作模式在此模式变换器中的变换过程。模拟结果表明,94 GHz回旋管中的TE02模在输出窗处被转换为能量集中的准高斯波束,转换效率为78.35%。     

开发出新型信息处理器件

日工业技术院电子技术综合研究所最近研制成新型信息处理器件,它能够把模拟信息转换成数字信息。其原理是将约瑟夫逊器件中产生的磁束量子(磁场的最小单位)作为信息的媒介,因而被称为磁束量子器件。与现有的约瑟夫逊器件相比,动作速度相同,但耗电量约为十分之一到百分之一。预期这个器件可在超高速、低耗电记忆线路上应用。     

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.……     

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.     

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.     

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.