脉冲涡流感应测量方法的研究

对脉冲信号激励的线圈在与其接近的金属导体中的涡流效应进行了时域分析,并对脉冲激励与检测电路的设计作了详尽介绍,为无损探伤、材质检验等领域提供了新的思路,扩大了电感式传感器的应用范围。     

基于霍尔元件阵列的缺陷漏磁检测技术研究

利用高灵敏度霍尔器件,设计研制了多通道阵列式漏磁检测传感器及信号处理电路.对不同几何参数的铁磁性试件缺陷进行了检测实验研究,该漏磁检测系统可实现地磁场激励和人工弱磁激励下的缺陷信号图像显示.探讨了基于多通道漏磁信号的缺陷表示方法,并利用人工神经网络技术对基于多通道传感器漏磁信号的缺陷反演问题进行了初步研究,表明利用霍尔元件阵列检测装置和人工智能信息处理方法,可以实现多通道漏磁信号与缺陷参数的非线性拟合,进而实现漏磁检测中的缺陷定量化分析.     

基于LabVIEW的超声导波时间反转信号激励系统

将时间反转信号处理方法运用于超声导波无损检测时,可实现检测能量在缺陷位置的聚焦,从而提高缺陷反射回波信号的分辨率,增强检测效果。本文在LabVIEW环境下设计开发了基于NI PXI 5411信号发生器卡和NI PXI 5112数字示波器卡的时间反转信号激励系统,通过单传感器单独激励时间反转信号后再叠加的方式实现近似时间反转导波检测。实验表明,该激励系统能有效地解决时间反转导波检测过程中的信号激励问题,具有较好的应用价值。     

基于电阻断层成像技术的立木探伤检测系统

为实现活立木内部缺陷的早期检测,同时摆脱立木腐朽检测中其他检测手段在实际操作中的局限性,提出将电阻断层成像技术应用到活立木内部缺陷的检测当中。该系统首先利用基于AD9850的激励信号发生器和压控电流源产生恒流激励信号,并遵循一定的激励方式循环输入到立木表面,然后利用基于双级程控放大器和AD637等微弱信号采集模块收集独立的边界电压值,最后输入到上位机通过等位线反投影算法实现电阻抗成像。实验部分将本系统应用在实际立木腐朽探伤检测中,结果表明本系统能够有效快速地反映出立木横截面的早期腐朽变色情况。     

PT对称结构同相和反相放大调制器的仿真研究

在现代微波和光通信系统中,迫切需要研制具有复合功能和特别性能的新型元器件。本文研究设计了一个包含电光介质和缺陷腔的一维PT对称结构模型,用于构造多功能复合器件。研究发现,该结构具有一个增益的缺陷模式。以该模式波长作为入射波载波波长,电信号调制成光信号的同时还被放大。通过设置偏置电场,调制的光信号还可以被同相或反相放大。在此基础上设计了一个消除信号噪声的模型。该研究对设计光集成器件具有一定的参考意义。     

无缝钢管折叠缺陷检测方法及装置

对于钢管内的折叠缺陷，许多探伤方法缺少检出能力。在由水耦合器、多通道高能量聚焦探头和冲击函数激励电路、脉冲宽度线性放大电路组成的检测装置中，采用“时分复用、高速抽样”技术和智能化计算机程序等技术，不但可以检出折叠缺陷，还可以检测钢管壁厚。检测速度１５ｍ／ｍｉｎ，检测精度±０．１ｍｍ。实验和长期应用证明这种检测技术是可靠的。     

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。     

一种IGBT短路保护驱动电路的优化

通过对IGBT短路失效原因的分析,提出了防止短路故障时IGBT失效的有效方法。进而对具有短路保护功能的EXB841驱动电路的各部分功能进行了详细地阐述,最后针对EXB系列电路存在的缺陷,给出了改进后的驱动电路。该电路不仅改善了因EXB模块过流保护起控点设置不合理带来的弊端,同时专门设置了延时封锁信号的功能,实现了对IGBT的软关断处理,避免了过流情况下硬关断所造成的危害。这对EXB系列驱动模块的进一步改进具有较大的参考价值。     

基于电磁共振的无线充电器研究与设计

研究了电磁共振技术的无线电能传输原理,并基于此原理设计无线充电系统。以常用电子器件构成,主要由电源管理电路、发射电路、接收电路和充电电路4个电路组成。该电路采用采用交直流供电,利用有源晶振发出高频激励信号和丙类谐振功率放大器,传送效率高。     

变形蔡氏电路的混沌保密通信仿真研究

为了便于蔡氏混沌电路的集成,设计了具有模拟电感的蔡氏混沌电路。在此电路基础上,进一步设计了混沌保密通信电路,并进行了仿真研究。结果表明,合适参数的发送信号在该混沌保密通信电路中能被很好地掩盖,也很难被窃听,发送信号和保密通信电路解调出来的信号是一致的,说明该通信电路具有很好的保密性能。但是当发送信号的幅度和频率超过一定值时,该混沌保密通信电路几乎不能实现对发送信号的保密。     

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.     

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.     

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.