光点位置测量系统摄像镜头设计

针对使用线阵列电荷耦合器件(CCD)的二维位置定位系统中的光学系统的特殊要求,本文提出一种以球面镜作为前组柱面镜作为后组,前组像面作为后组物面的二级成像结构作为线阵CCD的摄像镜头.该镜头使具有相同一维坐标值的点成像为同一条直线,并且具有广角视场,畸变小,成像质量优良等性能特点.对其设计思想、像差特点进行了分析,并给出了f'=.20 mm,2ω=74,畸变小于1.6%的柱面镜摄像镜头实例及其像差和传递函数计算曲线.     

曲线梁桥计算模型的探讨

文章通过对多个曲线半径、相同跨径的钢筋混凝土曲线梁桥和相同跨径的直线梁桥运用有限元分析软件MIDAS/CIVILL进行结构计算,再通过分析比较,讨论曲线梁桥内力及位移与曲线半径的关系,找到曲线半径对整个结构受力的影响规律,得出在平常设计中"以直代曲"的简化设计思想,指导设计工作。     

应用变焦曲线校正电动变焦镜头的电机原点

为了保证电动变焦数字监控摄像机的变焦步进电机和调焦步进电机的调节范围在厂家设计的可聚焦范围内,设计了一种基于变焦曲线的变焦电机和调焦电机的原点位置校正方法。首先,从镜头厂家提供的镜头变焦曲线中选定一条作为标准曲线。接着,利用自动调焦方法采集标准曲线对应距离下的实际变焦曲线。然后,计算标准变焦曲线的最高点和实际变焦曲线的最高点的偏移量。最后,在该偏移量附近的一个小范围内按照平方差最小的原则求出最佳偏移量即为原点位置的补偿值。在30倍光学变焦数字高清摄像机中实现了该方法,实验结果表明:48台采用本文方法成功校正的镜头在设计调节范围内均没有出现电机堵转和无法聚焦的现象,校正成功率96%,很好地解决了由于原点位置误差造成的问题。     

平凸标准镜头的研制

本文描述了在平凸标准镜头研制中,对计算精确度、制造精密度和镜座机械结构所作的考虑及达到的水平。该镜头已用干涉法加以验证及用OTF测量设备进行了测试,并都与依据镜头设计数据导出的理论上的OTF值作了比较。     

彩扩镜头的设计与选购（二）

彩扩镜头的设计与选购（二）文钟伯亮二、如何选择纯头的结构型式在确定了彩扩镜头的焦距后，对同一焦距，市场上往往有各种结构型式的镜头，价格相差很大。对设计者来说，在为某一种型号的彩扩机设计配套镜头时，也往往需要确定初始的结构型式。镜头的结构型式是由以下两...     

求解两端简支曲线梁面内内力和位移的精细传递矩阵法

该文应用精细传递矩阵法和曲线结构热胀变形规律,建立了在集中荷载和变温作用下两端简支曲线两面内内力及位移解的精细传递矩阵式。运用该文方法对一简支曲梁进行了计算,计算结果与曲线梁有限元结果吻合较好,从而验证了该文解答的正确性。将该文方法扩展运用与多跨曲线桥的求解,得出在变温和桥墩顶部摩擦力共同作用下多跨曲线梁的面内内力及位移的精细传递矩阵格式。建立实际曲线桥的有限元简化模型,通过结构有限元分析与精细传递矩阵法的计算结果比较,说明了该文理论具有很好的工程应用性,可作为曲线桥结构研究和设计的理论依据。     

某载炮车防冲击波驾驶室结构设计研究

以某型122 mm口径的车载榴弹炮为研究对象,分析炮口冲击波对于车身结构的影响,为车载榴弹炮的设计提供了依据。以载炮车的设计参数为边界条件,计算了极限工况下炮口非定常冲击波流场,并通过流场计算获得了车身表面的时间压力曲线。以此为输入边界条件,采用直接积分法计算了车身结构动态响应,得到了结构的应力以及变形响应并进行了实弹射击验证。针对仿真计算和试验中出现的薄弱区域,通过理论计算,总结设计出防冲击波驾驶室的典型特征结构,应用于驾驶室结构设计。通过分析重计算以及试验验证,结果表明:防冲击波驾驶室结构的防护性能良好,能够达到本车型驾驶室防冲击波的性能要求。     

空间TOF相机大视场光学镜头结构优化设计

为使空间TOF相机在不同温度的工作范围及复杂动力学环境下取得好的成像效果,该文对空间TOF相机大视场光学镜头结构进行了优化设计。首先,根据镜头的设计指标采用远心光路设计出光学系统。其次,选取ZTC4材料作为镜头支撑结构材料,并探讨了镜座的加工工艺。最后,利用有限元模型对镜头的镜筒厚壁进行优化设计。优化后镜筒质量明显减少,减重率达到32%,符合设计指标标准。     

航空相机光学系统热控设计

为保证航空相机光学系统的有效性和较高的成像质量,根据相机的热环境和结构特点进行了热控设计。采用热隔离等被动热控措施延长系统的热时间常数,降低光学系统对外部热环境变化的灵敏度。建立了镜头和窗口组件的传热模型和热阻网络模型,并对其在极端工况下的最大漏热率进行了分析计算,得到保持光学系统恒温所需的加热功率,根据计算结果设计了加热回路和分配加热功率。针对热控设计和航空相机的工况进行了稳态和瞬态仿真分析,对加热功率进行了优化。镜头和窗口的稳态温度分布均在(20±1)℃范围内,表明漏热补偿效果较好;瞬态分析结果表明,在飞行拍摄的过程中,温控系统将光学系统的温度控制在17.5℃～20.5℃范围内,满足热控指标要求,为提高光学系统的可靠性和热控设计优化提供了理论依据。     

风扇盘铣圆弧槽夹具的设计

本文主要介绍了SNECMA风扇盘340-000-420-0其中一关键工序——铣圆弧槽夹具的设计过程,对设计过程中的一些设计思想和计算方法进行了详细的阐述,特别是对主要结构进行了分析计算。     

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.……     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.