基于模糊神经网络的冷阴极潘宁离子源束流控制系统

设计了一种以TMS320LF2407A DSP器件为控制核心,以模糊神经网络控制为主要算法的智能冷阴极潘宁气体离子源束流控制系统.通过系统中嵌入的神经网络可实现对模糊控制的自适应调节,从而稳定离子源的引出束流,提高离子源的使用性能.     

小型潘宁离子源放电及引出特性的数值模拟

为更好地理解低气压、弱电离条件下潘宁离子源放电过程中离子和电子的动力学行为,建立了简化小型氢气潘宁离子源放电物理模型,采用粒子模拟与蒙特卡罗相结合(PIC/MCC)的方法,考虑了电子与氢气之间的弹性碰撞、激发、电离以及氢原子、离子之间的弹性碰撞和电荷交换等过程,实现了氢气潘宁离子源从放电到离子引出全过程的数值模拟。对结构优化前后潘宁离子源的电场和磁场进行了模拟计算,考察了空间不同位置处的离子和电子在其电磁场中的运动轨迹,分析了阳极电压和源内气压对放电过程的影响,得到了实验中难以在放电腔内诊断得到的电子与离子数密度分布,引出极离子电流等宏观参数与文献实验结果一致。通过数值模拟使得对氢气潘宁放电机制的研究从定性过渡到定量,这对于潘宁离子源的设计和改进具有重要意义。     

端部中空离子源的磁路研究

研究了端部中空离子源的磁路设计.在简要叙述端部中空离子源的基本原理及其对磁场要求的基础上,考虑了在设计离子源磁路时的关键问题和解决方法,并给出了实验结果和分析结论.     

潘宁放电溅射沉积纳米级AlN薄膜的性质

设计并制造了新的潘宁型等离子体源实验装置，分析了等离子体的发射光谱和产生AIN的动力学机理。在室温条件下，纯氮气的工作环境中用潘宁放电离子源溅射的方法，在Si（100）衬底上制备了纳米级的光滑平整AIN薄膜。本文用扫描电镜（SEM），原子力显微镜（ATM），红外吸收光谱（FTIR）和拉曼光谱（Raman shift）等测试分析技术用来研究了薄膜的微结构特征。     

考夫曼离子源多极磁场结构设计与数值模拟

论述了考夫曼离子源中两种磁场结构的特点.在采用多极磁场的离子源中,由于放电室内低磁场区的存在,可获得均匀性好的离子束流.采用环形永久磁体改进设计了考夫曼离子源的多极磁场,简化了磁路结构.运用Ansoft软件对多极磁场进行了数值模拟,结果分析表明设计是可行的,为该类型离子源的磁路优化设计提供了理论依据.     

用于中子管的微波离子源放电特性的仿真研究

微波离子源作为一种无阴极离子源,与潘宁离子源相比具有电离度高、形成的等离子体密度高、寿命长等优点。为了深入了解用于中子管微波离子源的放电特性,根据微波离子源的放电原理,设计中子管微波离子源的几何结构和所需磁铁的结构。结合Comsol多物理场仿真软件中的二维轴对称的AC/DC模块和微波等离子体模块,采用控制变量法,通过仿真实验探究了放电气压、微波输入功率、放电腔室大小以及放电腔室外壁材料对电子密度的影响,总结了电子密度在不同参数下的规律,将为中子管微波离子源的实验和设计提供重要支撑。     

用于中子管的微波离子源放电特性的仿真研究北大核心CSCD

微波离子源作为一种无阴极离子源,与潘宁离子源相比具有电离度高、形成的等离子体密度高、寿命长等优点。为了深入了解用于中子管微波离子源的放电特性,根据微波离子源的放电原理,设计中子管微波离子源的几何结构和所需磁铁的结构。结合Comsol多物理场仿真软件中的二维轴对称的AC/DC模块和微波等离子体模块,采用控制变量法,通过仿真实验探究了放电气压、微波输入功率、放电腔室大小以及放电腔室外壁材料对电子密度的影响,总结了电子密度在不同参数下的规律,将为中子管微波离子源的实验和设计提供重要支撑。     

端部霍尔离子源的磁场设计与数值模拟

首先简单介绍了用于离子束辅助沉积的端部霍尔离子源的工作原理，然后分析了其性能对磁场的要求，据此介绍了磁路组件的设计。最后,采用ANSYS大型有限元分析软件对一个条形的端部霍尔离子源的磁场进行了模拟计算，并与实验结果进行了比较，获得了满意的结果。通过对模拟结果的分析，获得了对该离子源磁场分布的直观深入的认识，为具体的端部霍尔离子源的改进设计提供了理论指导。     

等离子体交叉场调制开关的相关磁场模拟

等离子体交叉场调制开关(简称PCMS管)采用外加磁场的设计,基于冷阴极潘宁放电原理产生等离子体。本文应用基于有限元法的多物理场仿真模拟软件Comsol 4.0对PCMS管器件模型进行二维建模;同时,建立了电子在磁场作用下的漂移扩散模型;分别对磁场大小以及磁场区域的变化进行了模拟计算,重点讨论磁场的引入对电子密度分布的影响,从而确定磁场的最佳设置。     

二极型溅射离子泵抽速试验

冷阴极溅射离子泵是获得无油超高真空的重要工具之一。随着电真空器件的进一步发展,它越来越广泛地被应用于电真空工业中。但目前有关冷阴极溅射离子泵的设计理论还不十分完善,磁路设计在几何形状复杂多样的情况下,理论计算繁杂,与实际出入也大。在生产实践中,有不少参数和尺寸的考虑和选择,往往还经过试验结果来予以修正和确定。为给溅射泵的设计提供一定的实践经验,我们对影响二极式溅射离子泵抽速的主要因素:阳极电压、磁场强度以及阳极格的大小等作了一些初步试验,以探讨这些因素之间的相互关系;此外,对加有钛异华器的溅射泵也作了一些…     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from