ATM技术在拖线阵中的应用研究

拖线阵由于远离本舰工作。其水听器数据的传输需在阵内完成．拖线阵为获得不同的阵增益和工作频带，要求其声学孔径可灵活的进行增减。这要求采用的数据传输技术可适应声学孔径的这一变化．本文就ATM技术在拖线阵数据传输上的应用进行了研究，构成的ATM网络系统试验．结果表明。基于ATM技术的数据传输体系可支持声学孔径实现灵活扩展．     

一种微型光纤光谱仪的研制及其性能测试

报道了一种自行研制的微型光纤光谱仪及其性能测试结果.基于C-T(czerny-turner)成像系统,将通过光纤导入的待测光进行分光后成像于线阵CCD(charge-coupled device)探测器上.采用FPGA(field-pro-grammable gate array)作为主处理器实现CCD的驱动、数据采集与处理,通过USB 2.0接口将数据传送至上位机.根据USB的接口协议及数据格式,编写了一套光谱仪测试软件.利用汞灯作为测试光源,对自制的光纤光谱仪性能进行了仔细分析.结果表明,当采用缝宽为30μm的狭缝时,仪器的波长准确度小于0.3nm,光谱分辨率可达1.1nm.     

大视场线阵CCD图像灰度均匀化

针对大视场线阵 CCD 图像不均匀现象,提出了一种基于图像像素灰度补偿的均匀化方法。首先分析并计算线形目标上不同坐标位置的微小面元在线阵CCD上产生的辐射照度,并由此推导线阵CCD面元上不同像素灰度值与中心像素灰度值之间的关系,进而建立大视场线阵CCD像面上像素的灰度补偿模型,实现大视场线阵CCD图像快速均匀化的目的。对大量线阵 CCD 采集的高速路面图像进行了处理,结果表明我们提出的方法具有较强的可行性、鲁棒性和实用性。     

基于机器视觉的药用铝箔印刷品质检测系统

为适应制药行业对药用铝箔印刷品质的严格要求,在分析了印刷过程中对微小针孔、正面文字缺陷以及反面细小异物的检测需求后,开发了一套基于机器视觉的药用铝箔印刷品质检测系统。系统选配了线阵CCD相机、条形LED光源等硬件,搭建了高实时性、高清晰度的图像采集环境;采用基于Win Sock网络通信的系统架构作为检测软件,将多台工控机的处理结果通过网络通信传输给中控系统。经测试表明:此检测系统在现场能够稳定、高效运行,提高了药用铝箔印刷品质检测的自动化程度。     

轻武器远距离立靶精度测试方案的探讨

本文针对轻武器远距离立靶精度测试的技术要求,论述了CCD相机、激光器阵列、光纤编码、线阵CCD相机等立靶精度测试方案的优缺点和实现的可能性,同时也列举了国外相关立靶精度测试设备的原理和性能.本文对轻武器远距离立靶精度测试系统的研制与开发具有重要的指导意义.     

高速在线检测宽幅面彩色感光胶片质量

为降低线阵CCD拼接测量难度,提出改进的多光学系统线阵CCD拼接测量法。根据检测幅宽和精度要求,将较宽的被测幅面分成若干区域。各区域放置独立可调的光学成像系统及线阵CCD。调整各光学系统,使总成像范围覆盖整个被测幅面。几个线阵CCD同步驱动并行采集。图像信号通过PCI高速数据采集系统送入计算机。为提高判别速度,采用多尺度灰度形态学方法实现快速图像增强和缺陷判别,每秒钟可处理20幅2048像素200像素的8bit灰度图像。实验表明,可实现8个线阵CCD拼接检测幅面宽1.2m彩色感光胶片的表面质量,检测速度最高可达90m/min,可识别直径在0.1mm以上的缺陷,准确率在96%以上。     

一种线阵CCD图像灰度分布快速校正方法

提出一种应用于色选机的高速线阵CCD图像灰度分布校正方法，能够快速有效的提高线阵CCD图像质量。通过分析色选机成像系统中使用的大视场、大相对孔径光学系统的光能量衰减影响，高速线阵CCD的光电响应特性，建立了校正模型，模型中线阵CCD的各个光敏单元的衰减因子通过标准样板标定确定。采用FPGA实现校正模型，可在图像传输的过程中同时进行校正，每帧图像的校正延时不到0．1μs，满足色选机的高速处理要求。     

双相机高速交替成像时序控制系统

在破片坐标测试系统中,现有线阵相机的拍摄帧频尚不能满足要求.针对DALSA线阵CMOS相机Piranha4,设计了基于FPGA的双相机高速交替成像时序脉冲产生电路.以Xilinx公司的FPGA芯片XC6SLX9作为控制核心,并外置了按键电路.在ISE环境下利用VerilogHDL进行代码编写,在FPGA芯片内部生成对应网表,从而产生两路频率高达200kHz的脉冲,并通过按键使脉冲的脉宽、时延可调.通过脉冲对两台线阵相机进行控制,从拍摄图像的信息可知,两台相机的工作频率都达到了200kHz并且进行了交替拍摄.并且具有在不改变硬件电路的情况下,可以对时延、脉宽参数进行修改的优点.     

GJB289A与ARINC429双总线通讯接口卡设计

一些测试系统中,需要将GJB289A总线信号发送给发射装置,并接收经发射装置转换后的AR-INC429总线信号.本文通过对两种总线信号及相关型号芯片进行分析,提出一种基于FPGA的总线测试接口卡的实现方法,接口卡采用专用接口芯片PCI9054实现PXI接口.结果表明该总线接口卡能很好地满足快速数据处理和稳定高效的数据传输要求.     

宽幅胶片弊病在线检测系统的研制

研制了一种基于CCD成像和数字图像处理技术的宽幅胶片弊病在线检测系统.在红外光源提供均匀照明的条件下,采用两台高分辨率线阵CCD摄像机对运转速度为90 m/min、宽幅为1300 mm的胶片实时成像,利用简化了的平滑去噪和边缘检测算法进行处理,并通过双阈值判据及时发现弊病,保存弊病位置信息和弊病图像.系统检测能力为横向80 μm,纵向500 μm,能够检测出各种典型的弊病.     

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.     

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...     

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.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.