用于光合作用研究的光声光谱仪数据采集系统的改进

对本室研制的用于光合作用研究的光声光谱仪的数据采集系统作了改进.采用计算机采样,提高了采样频率和锁相放大器的时间常数.实验应用了基于最小二乘法的数字滤波技术、多通道采样技术、变频率采样技术.列举的实例证明,改进了数据采集系统的光声光谱仪,在性能上有了很大的提高.     

基于数字全息技术的变形测量

全息技术在测量、防伪中有大量应用.数字全息技术采用数字记录和计算机处理,实现测量的方法上有其特点.本文重点对数字全息技术实现变形测量的方法和具体算法开展了研究.论文首先总结了数字全息技术应用中的基本问题,包括数字全息算法问题和噪声抑制问题等.叙述了基于数字全息技术的变形测量基本思想,及相位恢复算法,同时分析了几种变形测量的实现方法,并提出了"2+2"步变形测量方法.该方法相对于"1+1"步变形测量方法,提高了测量精度,同时比"4+4"步变形测量法提高了动态性.本文建立了实验系统,获得了硬币的数字全息图,实现了常用的"1+1"步变形测量方法、相移算法的变形测量方法以及"2+2"步变形测量方法,给出了"2+2"变形测量的实验结果.实验结果表明在数字全息技术中结合相移技术进行测量,可以提高物波再现精度,进而提高变形等的测量精度.     

复杂零件精密尺寸测量方法的研究进展

随着各类机械零件集成化程度不断提高,其结构也越来越复杂,传统的测量技术已无法实现对现代复杂构造零件尺寸的精密测量.近年来出现的结构光三维测量、激光扫描测量等先进的测量技术克服了传统测量方法的不足,提高了尺寸测量效率和精度.归纳了结构光三维测量技术、机器视觉测量技术、蓝光扫描测量技术、激光三角法测量技术、工业CT尺寸测量技术的测量原理及研究进展,并对几种测量技术的优缺点和精度进行了对比分析.     

基于.NET框架的燃气调压器选型软件的设计

基于VC .NET框架,采用数据库技术中的ADO访问方式,再结合ACCESS、EXCEL和DLL等技术,开发了燃气调压器的自动选型软件.它提高了产品选型的效率,缩短了产品开发的时间.     

智能电网视域下发电机的继电保护分析

研究智能电网下发电机继电保护措施,提高发电机运行效率.分析智能电网视域下发电机继电保护现状,针对存在的问题制定可行的技术方案,引入单元件保护技术、广域保护技术、重构技术、电子传感技术、电网自愈技术、通讯技术、设备技术以及控制决策技术等.继电保护装置实现自动化、网络化发展,可以及时检测电力系统的运行状态.智能电网可以有效提高电力服务水平,实现电力系统继电保护装置的自动化检测功能,全面提高了电力水平.     

棒、线材轧制的发展趋势

本文介绍了几项轧钢技术的改进,这些改进为轧钢厂提供了提高产品技术性能、尺寸范围和金属收得率,降低了生产成本,提高了车间利用率.     

振动时效技术的发展

论述了振动时效消除材料内应力,稳定尺寸精度,提高材料强度和使用寿命的作用机理.分析了传统振动时效技术即亚共振技术在推广应用中存在的问题.进而介绍了频谱谐波技术的优势及其应用举例和前景.     

低压TSC动态无功补偿系统若干问题的探讨

为了提高现有TSC系统补偿的实时性和稳定性,分析并探讨了现有的TSC动态无功补偿系统技术.从无功算法、补偿原理、控制策略、补偿主电路结构等5个方面论述了TSC系统相关算法和技术.通过比较各种方法的优缺点,给出了选择的依据,并且详细介绍了TSC系统在研制过程中需要注意的地方.研究结果表明.采用合理的算法和技术能有效提高TSC系统的性能.     

浅析工程项目管理视角下应用计算机应用技术的效果

科技的发展推动了社会经济的发展,尤其是各种计算机应用技术,在各行各业中得到了广泛使用.计算机应用技术具有高效、功能丰富的优势,且发展速度较快.该技术在工程项目管理中的应用能够提高管理效率和质量,因此,需要采取有效的措施来推动该技术的合理利用,从而提高工程项目管理水平.本文主要针对工程项目管理视角下计算机应用技术的应用效...     

基于Bluetooth技术的液压在线故障监测诊断系统

介绍了基于Bluetooth技术的液压在线故障监测诊断系统的设计,给出了系统组成和软件设计.液压在线监测故障诊断系统采用Bluetooth无线接口代替现场有线电缆,提高了数据通信的抗干扰性能.阐述了实现Bluetooth技术协议的整体框架、主要工作流程和电路接口.实验表明:该系统提高了液压系统故障推理的正确性和推理速度.     

The vibration behavior of impeller blades in the five-axis CNC flank milling process

Today, in most cases, impellers of centrifugal compressors are produced by flank milling on five-axis CNC milling machines. The complex three-dimensional geometry of the very thin blades consists of ruled surfaces. The flank milling process allows a fast production of the impellers and the surface of the blades is of high quality. The limited strength of the very thin blades and also the thin outer radial part of the disk lead to a high sensitivity to static and especially dynamic forces that are caused by the instationary flow in the impeller. The dynamic forces of rotating stall and surge are the most dangerous excitations of the bladed disk. Coupled vibrations may occur and damage the impeller. The highest static load is caused by the centrifugal forces. Therefore, most of the high-loaded impellers are manufactured from aluminum alloy or titanium because of the low density of this light metals and the relatively high strength. Most of the interests and the investigations in the last years are paid to the vibration behavior and the dynamic loads of the impeller during operation. But sometimes, the highest stress may occur during the production process and damage the impeller or weaken the strength and so cause later problems. Especially, excitations from the dynamic forces during the flank milling process have to be taken under consideration. The vibration behavior of the impeller is very complex and is affected by the vibration behavior of the cutter and the milling machine. In this paper, the change of the vibration behavior of centrifugal compressor impeller blades during the manufacturing process is investigated. During the finishing of the thin blades, the blade thickness is continuously changing and also the strength and the corresponding eigenfrequencies of the blade. The dynamic forces acting on the blades are caused by the cutter, the milling machine, and the cutting process. The quantity of the forces and the frequency of the excitation are determined by the rotational speed of the cutter, the feed, the number of edges, and the chip thickness. The results described in this paper give useful information about the change of the vibration behavior of the centrifugal impeller blades during the flank milling process and possible interaction with the cutter and the machine.     

Design and Analysis of the Gemini Chain System in Dual Clutch Transmission of Automobile

Chain drive system is widely used in the conditions of high-speed, overload, variable speed and load. Many studies are focused on the meshing theory and wear characteristics of chain drive system, but system design, analysis, and noise characteristics of the chain drive system are weak. System design and noise characteristic are studied for a new type Gemini chain of dual-clutch automatic transmission. Based on the meshing theory of silent chain, the design parameters of the Gemini chain system are calculated and the mathematical models and dynamic analysis models of the Gemini chain system are established. Dynamic characteristics of the Gemini chain system is simulated and the contact force of plate and pin, plate and sprockets, the chain tension forces, the transmission error and the stress of plates and pins are analyzed. According to the simulation results of the Gemini chain system, the noise experiment about system is carried out. The noise values are tested at different speed and load and spectral characteristics are analyzed. The results of simulation and experimental show that the contact forces of plate and pin, plate and sprockets are smaller than the allowable stress values, the chain tension force is less than ultimate tension and transmission error is limited in 1.2%. The noise values can meet the requirements of industrial design, and it is proved that the design and analysis method of the Gemini chain system is scientific and feasible. The design and test system is built from analysis to test of Gemini chain system. This research presented will provide a corresponding theoretical guidance for the design and dynamic characteristics and noise characteristics of chain drive system.     

超洁净制造的研究与发展*

制造学科是随着科学的演进和技术的进步不断地发展和变化的一个学科。结合激光聚变、电子制造、航空航天以及医疗器械等领域对洁净的需求,首次提出了超洁净制造的新概念,并对超洁净制造的内涵进行了界定。在上述相关领域中,表面污染物的演化和演变将对器件的性能和功能产生重要的影响。采用制造领域的新方法和新手段获得超洁净表面,并实现其工作时超洁净状态的维持是制约上述领域发展的瓶颈问题。在综合分析超洁净制造应用领域的基础上,提出超洁净制造基础理论和关键技术研究所面临的挑战,分析超洁净制造的技术内涵和研究内容,并针对相关领域中高洁净度的获得和保持技术进行了剖析。最后,提出超洁净制造未来发展的科学问题。旨在通过超洁净制造的研究为制造科学与工程提供新的发展思路,拓展并提升其应用的领域,服务于重大科学工程和重要技术领域的发展。     

一种新型弱耦合三平移并联机器人机构及其运动学分析

提出一种弱耦合2RRPaR+PPaP三平移操作机器人机构,分析了机构的自由度及拓扑结构特征;推导了机构的正逆解方程以及速度、加速度模型,根据速度雅可比矩阵,分析了机构的奇异位置;根据机构的逆解方程和主要约束,采用三维极坐标边界搜索法绘制了机构的工作空间三维实体图和截面图;由ADAMS三维模型仿真和运动正解方程计算所得的位移、速度、加速度曲线基本一致,验证了运动方程的正确性。该机构解耦性好、结构简单、运动灵活,在纵向移动方向上具有部分解耦和工作空间大的优点,适合用作生产线自动操作手机构。     

可调速皮碗结构强度与通流特性数值仿真研究

皮碗作为管道机器人常用动力装置,利用管道流体作用于其两端压力形成的压差作为整体装置动力来源,因其适用管道口径范围广、结构简单被广泛的关注与应用。皮碗在管中移动过程中随着管道压差变化发生相应变形,如果变形过大,可能导致皮碗脱离管壁造成驱动失效;如果管内压差及管壁间的摩擦力超出了皮碗的变形范围,则可能使皮碗发生破损。因此,皮碗结构的设计对于其自身结构强度及管道前后的通流特性具有重要意义。以外径100 mm皮碗为研究对象,通过系统仿真分别计算分析不同直径、厚度皮碗在不同压差时的最大接触应力、位移变化及管道前后两端的通流性能,得到皮碗在不同厚度和工作压差时皮碗相关性能的变化规律,为管道机器人皮碗的设计提供理论依据。     

3D thermomechanically coupled FEM analysis of large disk rolling process and trial production

Recently, rolling technique used to manufacture rings with various dimensions, shapes, and materials is innovated to a revolutionary technique for the fabrication of large disks. In this paper, in order to study the forming capability of this novel method, its principle was introduced, and the 3D thermomechanically coupled FE model was established using the dynamic explicit code ABAQUS/Explicit. Considering the adaptive treatment of boundary conditions, the user subroutines of ABAQUS were explored based on the movement law of the guide rolls and profiled axial rolls, and contacts between these rolls and the disk component. And the reliability of the FE model was verified theoretically and experimentally. Furthermore, the extending rule of plastic deformation zone and the effect of feed speed on the size of both the outer and inner diameters were investigated. The main results show that (1) the smallest equivalent plastic strain (PEEQ) occurs at the hub of the disk and the junction of the rim and the web, and the larger PEEQ appears on the outer surface of the rim and the web of disk. (2) Both the outer and inner diameters of the disk increase gradually at the beginning stage and more and more rapidly at a later stage. With the increase of the feed rate, the increase rate of both the outer diameter and inner diameter will decrease and the lateral spread rate will increase. And trial production of the large disk based on the analysis had been carried out successfully on the revamped Wagner RAW500/400 radial-axial ring rolling mill.     

基于毛细力的芯片微操作方法研究

提出一种基于毛细力的芯片微操作方法,可实现微芯片的精准拾取、释放以及与尺寸匹配的基底的高精度自对齐。开发可精确模拟液桥形态的双迭代算法,求解微芯片操作过程中的拾取力与释放力,深入研究基于毛细力的微芯片的拾取以及释放的机理以及必要条件。研究液滴体积、基底接触角对微芯片拾取力和释放力的影响。结果表明,拾取力和释放力均随液滴体积的增大而增大,释放力随基底接触角的减小而增大。进一步通过试验验证基于毛细力的芯片微操作方法的可行性,研究液滴体积对微芯片操作的影响,并统计微芯片操作的成功率。基于毛细力的微操作方法在软体机器人、微机电系统、可穿戴设备的集成等领域具有潜在应用。     

Numerical study on the dynamics of an electrical discharge generated vapor bubble in EDM with different shapes of the tool and the workpiece

In this paper, the effect of the shapes of the tool and the workpiece on the dynamic behavior of an electrical discharge generated vapor bubble in the process of EDM (Electrical Discharge Machining) is investigated. The boundary integral equation method is employed for numerical simulation of the problem. Results show that in the case of the concave tool and workpiece the lifetime of the electrical discharge generated vapor bubble is longer than the case of the flat tool and workpiece. By increasing the concavity of the shapes of the tool and the workpiece, the lifetime of the bubble increases. Results also show that in the case of the convex tool and workpiece, the lifetime of the electrical discharge generated vapor bubble is shorter than the lifetime of the bubble in the case of the flat tool and workpiece. In this case also, by increasing the convexity of the shapes of the tool and the workpiece, the lifetime of the bubble decreases. Numerical results show that in the case of the concave tool and workpiece the rate of pressure drop on the surface of the workpiece is higher than the rate of pressure drop on the workpiece in the cases of the flat and convex tool and workpiece. The high rate of pressure drop on the surface of the workpiece leads to the ejection of more molten material from the crater and consequently leads to more material removal rate.     

压裂泵滑动轴承流体动压润滑性能研究*

压裂泵的十字头滑履与导板间隙、供油流量和油压等关键参数,目前主要通过工程经验进行调节,缺乏科学依据,易致导板磨损和烧瓦,严重影响压裂泵服役寿命。针对以上问题,建立3500HP压裂泵的轴瓦、轴承间隙及润滑油组成的流体力学系统,利用计算流体力学软件Fluent进行滑动轴承的流场分析,考察润滑油黏度、轴瓦间隙、润滑流量、润滑油压对压裂泵用滑动轴承的影响。结果表明：随着滑履与导板间隙的减小,导板的形变与应力会增大,最优导板间隙为0.5 mm左右;增大供油流量会使导板的形变与应力降低,供油流量最好不低于2.2 L/min;增大供油黏度会使导板的形变与应力变大,在0.2~0.4 Pa·s范围内供油黏度越小越好;随着供油油压的增大,导板的形变与应力增加显著,当油压大于4 MPa时,导板的应变与应力呈现指数级增大,当供油油压为3 MPa时,导板的形变与应力达到最小值。     

机械设备管理中机械修理维护的意义及效果分析

当代社会,经济、科技领域飞速发展,群众及社会各企业对机械设备的依赖性显著提升。在这一大环境下,各企业应该全面落实机械设备管理工作,确保相关设备能够保持良好的运行状态。机械修理与维护部分工作是设备管理工作中的重点内容。工作人员基于现实情况,有效排查设备的故障原因,并做出相应处理,能够使本企业设备管理水平大幅提升。目前,各企业机械设备修理与维护工作已然初具规模,其设备管理水平、运行质量均显著提升。本文以机械设备修理与维护工作为中心展开探讨,对其在机械设备管理工作中的开展意义、优化开展策略等方面进行细致分析。