一种基于DSO的高频信号采集方法

为了采集到高频信号,本文采用配有高速A/D转换器的数字存储示波器(Digital Storage Oscilloscope,简称DSO)设计了一个高速数据采集系统.该系统借用DSO强大的实时数据采集系统,通过将DSO连接至计算机,并在计算机装上有关驱动软件后构成.该系统能够采集到带宽大、频率高的高频信号并且能够与计算机进行数据通讯.使用时可以根据信号的特征在计算机上安装相关软件程控DSO,设置DSO的有关参数及工作方式,采集信号的数据及波形,用于分析及处理.实验证明应用这种方法设计的高频信号采集系统经济实用、方便灵活,具有很强的实用及经济价值.     

一种测量超声波速度的方法

提出了一种测量超声波速度的方法。这种测量方法基于调节激发超声换能器电信号的频率。发射超声波的换能器与接收超声波的换能器正对着且共轴设置,数字示波器同时读取激发超声换能器的电信号和接收到的超声波信号,而且激发超声换能器的电信号被设置为参考信号,调节激发超声换能器的电信号的频率直到示波器显示的两信号波形重叠,记录此时电信号的频率。根据这两信号相邻两次重叠的频率差,计算得到超声波的速度。这种测量方法准确、快速,而且操作简单、方便。     

超声引线键合过程的信号采集与分析系统

根据超声引线键合实验平台结构,设计PZT(压电陶瓷)驱动信号传感电路,搭建键合力传感系统,集成多普勒振动测试系统,获得键合过程中的换能器驱动电压、电流、劈刀振动和键合压力信号.采用PCI6110数据采集卡,开发基于LabView8.2的采集软件,实现上述4路信号的同步采集、显示、频谱分析和保存.采用小波时频分析方法对电流信号进行分解,发掘电流信号中与键合质量相关联的一些特征.研究结果表明:信号采集系统能高速、同步采集键合过程中的多路信号;电流信号基频的频率、幅值及变化趋势都在一定程度上反映了键合质量;当电流信号频偏离正常值太大、均值太小和变化趋势异常时都表明键合失效.     

数字超声电视测井车内计算机及实时信号处理技术

数字超声电视测井车内配备有一台IBM-PC/AT计算机,负责测井现场数据采集、处理及最后结果的输出.换能器旋转一圈,计算机可获得512点8bit的灰度信号、512点12bit的回波时间信号以及温度、深度、同步信号等.总数据率为92.16kbit/s.     

一种在微计算机上实现数字示波器功能的方法

介绍了在微计算机上加装多通道A／D转换卡以构成多通道信号采集系统的方法，并设计了一套专门的对数据进行处理的软件，可在微计算机上实现数字示波器的功能，该装置可在一定程度上实现信号测量、波形显示、数据存储等功能，特别是在被测信号频率很低时是一种非常好的慢扫描示波器．     

面向实时控制任务的高速数据采集存储方法

提出一种基于CAN总线,面向实时控制任务的高速数据采集存储方法.该方法将数据实时采集、系统实时控制、数据存储与显示分配在相互独立的处理单元中实现,处理单元之间通过独立的CAN网络进行通信.该数据采集方法解决了数据实时采集与系统实时控制之间的矛盾.利用队列技术,该方法解决了数据存储与数据实时显示之间的矛盾.该数据采集存储方法已成功应用到某大型仿真系统中.     

驻波法测声速的原理研究

压电换能器是一种能够将机械能和电能互相转换的功能性材料。利用压电发射换能器将信号源发射出的电信号转变为声波信号,并将声波近似地看为平面波。经过压电接收换能器的反射,在其界面上形成的两列振幅相同、频率相同的波相干叠加产生了驻波。利用示波器与压电接收换能器相连,在示波器上可以观察到压电换能器形成的声压波形以及振幅的大小。移动接收换能器记录声压处于极大值时发射换能器与接收换能器之间的距离。利用该方法测量多组数据,并用逐差法即可求得声速。     

超声焊接的研究和工艺模型

为了能进行超声焊接工艺的线检测，必须了解超声焊接的机制。本文对这个问题作了研究。在本实验所用的焊机中，用一块压电晶体作为换能器产生超声振动。在通常的焊接过程中，研究了换能器驱动信号和从机械振动测出的信号这二者的变动情况，同时还研究了这二种信号的各次谐波信号。     

基于FPGA控制VGA显示的双通道数字示波器

本系统以FPGA芯片XC3S500E为控制核心,辅以信号调理电路、AD采样电路、触发电路、存储电路等外围电路,设计出了一种具有VGA显示功能的双通道数字存储示波器。该系统实现了数字信号上升沿或下降沿触发、0-1MHz信号的数据采集、一键数字存储与回放和驱动VGA显示器实时显示当前波形等功能,并可以通过按键进行垂直灵敏度和扫描速度的挡位设置。     

基于开孔球面高强度聚焦超声阵列的相控精度设计

研究了超声换能器阵列驱动信号的相位调控精度对阵列聚焦声场的影响.基于开孔球面高强度聚焦超声(HIFU)阵列,提出了一种阵列驱动信号的5位量化精度相控方案,解决了相控HIFU治疗系统中驱动信号相位的非连续性调控问题.仿真结果表明,此种相控方案既使阵列声场保持了高声强的聚焦点,又维持了原有的栅瓣抑制能力,从而为相控HIFU阵列驱动系统的设计提供了可靠依据.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.