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1.
针对自制垂直引入式飞行时间质谱仪(orthogonal extraction time-of-flight mass spectrometer, O-TOFMS)的需要,运用直接数字频率合成 (direct digital frequency synthesis,DDS)技术,研制了射频四极杆的高压射频驱动电路装置。该驱动器频率可调范围为0.5~2 MHz,幅度最高达到1 000 Vp-p。该射频四极杆驱动器(radio frequency quadrupole driver,RFQ Driver)可用于分子离子反应器(molecule ion reactor,MIR)和RFQ驱动,其结构简洁、成本低、性能稳定可靠。  相似文献   

2.
To shorten the product development cycle time and reduce the cost at the same time, which is very critical for the survival of those small and mid-sized one-of-a-kind production (SMOKP) companies, various computer communication, simulation and computer aided engineering and management techniques have been widely used in these SMOKP companies. However, according to our study, the applications of these advanced computer technologies in these SMOKP companies are lack of system integration and synergy, which result in communication errors, reworks, duplications and hence a longer product development lead time and a higher cost. To solve this problem, an inter/intranet based computer aided rapid product development system is presented in this paper. This system consists of a number of inter/intranet based computer models or sub-systems for supporting rapid development of a one-of-a-kind product. It also employs a novel concurrent product development strategy called “prototype based incremental product development strategy” and an integrated product data structure called “product production structure”. Some industrial implementations of the proposed system, product development strategy and product data structure are also reported in the paper.  相似文献   

3.
To shorten the product development cycle time and reduce the cost at the same time, which is very critical for the survival of those small and mid-sized one-of-a-kind production (SMOKP) companies, various computer communication, simulation and computer aided engineering and management techniques have been widely used in these SMOKP companies. However, according to our study, the applications of these advanced computer technologies in these SMOKP companies are lack of system integration and synergy, which result in communication errors, reworks, duplications and hence a longer product development lead time and a higher cost. To solve this problem, an inter/intranet based computer aided rapid product development system is presented in this paper. This system consists of a number of inter/intranet based computer models or subsystems for supporting rapid development of a one-of-a-kind product. It also employs a novel concurrent product development strategy called “prototype based incremental product development strategy” and an integrated product data structure called “product production structure”. Some industrial implementations of the proposed system, product development strategy and product data structure are also reported in the paper.  相似文献   

4.
光电容积描记图(PPG)是一种利用光学技术无创检测人体心血管脉搏波的方法。PPG信号来源于MIMIC数据库,它含有许多生理信息。本文提出了将集合经验模态分解(EEMD)、倒谱、快速傅里叶变化和过零点检测相结合的方法,从PPG中可靠地估算脉搏率(PR)、心率(HR)和呼吸频率(RR)。首先,将PPG信号通过EEMD分解为有限个固有模态函数(IMF)。因为EEMD有自适应滤波特性,所以估算不同的生理参数时,可以用不同的IMF分量来重构信号。其次,估算脉搏率时,舍去低频含有伪迹的IMF,再通过过零点检测可以得到瞬时脉搏率。然后,估算心率时,用1 Hz~1.67 Hz(60次/分钟~100次/分钟)的IMF来重构信号,再求倒谱,选取反映心脏活动的频带来得到心率。最后,估算呼吸率时,用0.05 Hz~0.75 Hz(3次/分钟~45次/分钟)的IMF来重构信号,然后对呼吸信号求快速傅里叶变化得到频谱图,寻找频谱图中的峰值得到呼吸率。对来自MIMIC数据库的53个成人PPG信号进行了仿真。仿真结果表明使用该综合信号处理方法提取的生理参数与实际生理参数一致,且该方法有运算量小,精确度高的优点(误差不超过1.17%)。  相似文献   

5.
6.
郭巧珍  杜振霞 《质谱学报》2011,32(2):112-116
建立了二苯甲烷二异氰酸酯(MDI)的超高效液相色谱-串联质谱(UPLC-MS/MS)联用的分析方法。实验用甲醇作衍生试剂,将二苯甲烷二异氰酸酯衍生成二苯甲烷二氨基甲酸甲酯(MDC),通过测定二苯甲烷二氨基甲酸甲酯来确定二苯甲烷二异氰酸酯的含量。实验采用Waters Acquity BEH C18超高效液相色谱柱,甲醇-0.1%甲酸作为梯度洗脱液,二苯甲烷二氨基甲酸甲酯在1.5 min内与其他化合物进行完全分离,经四极杆质谱选择离子监测模式检测。线性范围为2~100 μg/L,检出限为1 μg/L,相关系数0.999 4。考察了水、甲酸、甲酸铵流动相体系,以及进样量大小对样品的分离效果,发现甲酸流动相体系的分离效果优于其他两种流动相体系,同时发现在进样量大时出现平头峰。并且在优化条件下,对实际样品中游离的二苯甲烷二异氰酸酯进行了测定。  相似文献   

7.
介绍了网络虚拟现实建模语言(VRML),VRML具有动态对象描述和超链接、通用性、扩展性、易实现性等特点。VRML浏览器和生成VRML文件的工具广泛使用于多种平台的计算机,是虚拟制造VM与虚拟设计中的网络虚拟现实技术的基础。  相似文献   

8.
目的:探讨甲胎蛋白(AFP)、糖类抗原199(CA199)、谷氨酰转肽酶(GGT)和碱性磷酸酶(ALP)单独或联合检测对原发性肝癌(PHC)的早期诊断价值。方法:本研究为回顾性研究,筛选2016年-2019年本院87例原发性肝癌(PHC)患者、105例慢性乙肝患者及104例健康志愿者,收集不同组首次入院和体检外周血检测数据和其他临床资料。比较各血清指标在组间差异性,分析了血清学指标与入组PHC临床分期和病理分型的相关性,进一步利用ROC曲线法分析血清指标单项与联合诊断的灵敏度、特异度。结果:AFP、CA199、GGT、ALP检测均值在PHC组均明显高于慢乙肝组和健康体检组。AFP阳性检测值与PHC临床分期(r=0.9536)和病理分型(r=0.525)呈正相关性。AFP诊断PHC灵敏度和特异性分别为60.87%和77.97%、精准度AUC为0.726。联合四项指标检测灵敏度、特异度和AUC分别为75.36%、65.64%、0.806。结论:AFP、CA199、GGT、ALP四项指标联合检测可提高原发性肝癌早期诊断的准确率,操作性强且易于推广。  相似文献   

9.
基于工业设计和先进制造技术的产品快速开发   总被引:9,自引:0,他引:9  
提出一种将工业设计与逆向工程(RE)、CAX技术、快速成型和快速模具结合起来的集成开发模式。在该模式下,利用RE技术直接将工业设计获得的实物模型转换为数据模型。数据模型在CAD系统中进行处理,构造曲面模型或STL模型表面、再经过STL模型表面的偏置处理,利用RP和RT技术直接、快速的制作出样件或小批量成品,利用CAM系统还可以输出机械加工需要的数据代码。本文洋细介绍了该模式的组成部分、工作流程以及接口等关键技术,并以一个实例来说明该模式的正确性和高效性。  相似文献   

10.
In this report the combined method of correlation radar signal (RS) processing based on the theory of atomic functions (AF) is examined.Examples of using of new Kravchenko probability weight functions (WF) designs are presented.Quality functional to estimate accuracy and efficiency of RS processing for concrete physical models is constructed.It is shown that the proposed approach significantly improves the quality of the coherent analysis of RS.  相似文献   

11.
To investigate on the crystalline structure of AISI M2 steel by using tungsten–thorium electrode in electrical discharge machining (EDM) process was studied. Furthermore, the investigation were carried out for finding the value of material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) of tool steel material depending upon three variable input process parameters. On the basis of weight loss, the value of MRR and EWR were calculated at optimized process parameter. Subsequently, surface topography of the processed material were examined through different characterization techniques like scanning electron microscopy (SEM), Optical surface profiler (OSP) and Atomic force microscopy (AFM), respectively. In XRD study, broadening of the peak was observed which confirmed the change in material properties due to the homogeneous dispersion of the particles inside the matrix. Lowest surface roughness and MRR of 0.001208 mg/min was obtained. Minimum surface roughness was obtained 1.12 μm and 2.18427 nm by OSP and AFM study, respectively. Also, minimum EWR was found as 0.013986 mg/min.  相似文献   

12.
一种基于Agent的Job Shop调度模型   总被引:3,自引:0,他引:3  
在讨论传统生产调度思想的基础上,针对调度系统需要解决的降低复杂性及动态调度的快速响应问题,提出了一种基于多代理技术的Job Shop调度模型。给出了基于多代理的车间作业优化调度系统结构,并开发了原型系统,实验结果表明,此方法调度性能良好。调度过程快,适应于需要动态响应的环境。  相似文献   

13.
Face milling is a process predominantly affected by dynamic variation of cutting forces, thermo-mechanical shocks and vibration leading to catastrophic tool failure along with gradual wear of the inserts. Keeping in view the industrial importance of this process, it is necessary to devise suitable methods to predict in advance the onset of tool failure without grossly impairing the machining set-up and the job. Hence, the applicability of back propagation neural network with delta bar delta learning rule for faster convergence has been studied with the above objective. The multi sensor based tool condition monitoring strategy shows that the learning rate adaptation scheme combined with the selection of suitable process parameters drastically reduces the training time of the artificial neural network without dispensing with the prediction accuracy.  相似文献   

14.
使用独特的镶拼矩形TiAl靶,用中频反应磁控溅射方法,采用周期性改变靶电流的方法在高速钢(W18Cr4V)基体上沉积了(Ti,Al)N多层薄膜.利用场发射扫描电镜、纳米硬度仪和x射线衍射仪等方法研究了(Ti,Al)N多层薄膜组织结构、硬度和膜基结合性能.结果表明,制备的(Ti,Al)N多层薄膜硬度略低于20GPa.弹性模量均大于230GPa,薄膜的临界载荷均大于50N;多层薄膜有一定的择优取向,且择优取向随着靶电流周期性的改变而有所变化.同时发现,(Ti,Al)N多层薄膜硬度是结构、界面和择优取向共同作用的结果.  相似文献   

15.
AS-interface是一种用于连接二进制传感器和执行器,工作在自动化体系最底层的网络系统。由于容易使用,操作可靠,应用量大等特点,也可用于机械安全领域。安全AS-interface系统可达到EN954-1规定的四级安全应用,并且可将标准部件和安全部件混合使用。  相似文献   

16.
Electrochemical micromachining (EMM) could be used as one the best micromachining technique for machining electrically conducting, tough and difficult to machine material with appropriate machining parameters combination. This paper attempts to establish a comprehensive mathematical model for correlating the interactive and higher-order influences of various machining parameters, i.e. machining voltage pulse on/off ratio, machining voltage, electrolyte concentration, voltage frequency and tool vibration frequency on the predominant micromachining criteria, i.e. the material removal rate and the radial overcut through response surface methodology (RSM), utilizing relevant experimental data as obtained through experimentation. Validity and correctiveness of the developed mathematical models have also been tested through analysis of variance. Optimal combination of these predominant micromachining process parameters is obtained from these mathematical models for higher machining rate with acuuracy. Considering MRR and ROC simultaneously optimum values of predominant process parameters have been obtained as; pulse on/off ratio, 1.0, machining voltage, 3 V, electrolyte concentration, 15 g/l, voltage frequency of 42.118 Hz and tool vibration frequency as 300 Hz. The effects of various process parameters on the machining rate and radial overcut are also highlighted through different response surface graphs. Condition of machined micro-holes are also exhibited through the SEM micrographs in this paper. Pulse voltage pattern during electrochemical micromachining process has been analyzed with the help of voltage graphs. Irregularities in the nature of pulse voltage pattern during electrochemical micromachining have been observed and the causes of these irregularities are further investigated.  相似文献   

17.
This paper presents the performance results of a Virtual Instrument (VI) based in Case-Based Reasoning (CBR), conceived to online monitor the power-quality. The PC-based instrument receives data through a DAQ board and a differential probe, while maintaining economy by eliminating the extra network construction and hardware. Being flexible, presents an user-friendly interface and a large data storage capacity, since it uses the hard disk. The computational guts of the instrument are based in third and fourth-order statistics (along with the variance), which enhance detection capability and reject noise influence. A time-domain sliding window sweeps the register under test and offers a time-variation pattern which reflects the deviation of the statistical estimator with respect to the steady state. This three-valued time-series comprises variance, skewness and kurtosis evolution, and constitutes a triple input to the innovative CBR module, which in turn is capable of distinguishing electrical anomalies among five categories (the sixth is reserved to the healthy signal): non-50 Hz, 50-Hz-asymmetrical, 50-symmetrical non-sinusoidal, swell and sag. Online surveillance tests developed over the local electrical network show acceptable accuracy (96%).  相似文献   

18.
芴基荧光聚合物材料合成中间体的质谱分析   总被引:1,自引:0,他引:1  
袁敏  候琼 《质谱学报》2002,23(2):85-85
本文报导了新化合物 2 ,7-双 ( 4,4 ,5 ,5 -四甲基 -1 ,3 ,2二氧杂硼烷 -二基 ) -9,9-二辛基芴的 EI和 ESI的质谱 ,利用质谱 -质谱 ( MS/ MS)分析 ,确认了该谱图中母离子和子离子的关系 ,讨论了其碎裂途径 ,为其结构鉴定提供了依据  相似文献   

19.
本文介绍GG1B(F)(Z)型高压开关柜及如何实现整体式真空断路器与隔离开关操作可靠机械联锁。  相似文献   

20.
This paper documents part of a research program which has been under way at the CIM Centre at Swinburne University of Technology since 1989. The purpose of the research program was to develop an open-architecture machine tool control system and then to see how that system could be used to change the distribution of traditional manufacturing design, planning and control functions. This paper examines one part of that research program and focuses on a methodology which could prove to be useful in the machine tool selection, cutter selection and cutter path generation phases of process planning for cutting operations on workpieces in computer-controlled machine tools.It is suggested that a configuration space transform be used for each cutter/machine tool combination to find the volume that the combination could remove from the uncut workpiece without removing any of the material that will form the final workpiece. A method of comparing these volumes from different combinations is then outlined. The output of this method is a reasonable sequence of machine tools and cutters. Path planning can then be carried out for each of the chosen combinations using a method similar to the one used to find the possible volume to be removed.Possible implementation techniques, and their limitations on existing computer hardware, are discussed and the most promising of these are identified, based upon some properties of configuration space transforms.  相似文献   

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