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1.
1 Introduction Computerintegratedmanufacturing (CIM)asaphi losophyhasreceivedworldwideattentionsincethe1980sandhasbeenappliedtodirectenterprisespro ductionsuccessfullyinmanyindustrializedcoun tries[1] .TheUSgovernmenthasconsideredtheman ufacturingindustrytob…  相似文献   

2.
1 Introduction AB5 typehydrogenstoragealloyshavebeeninten sivelyinvestigatedsincethefirstuseasanelectrodereportedbyJustiin 1973[1] .ThecommercialAB5electrodesusemischmetal,alowcostmixtureofrareearthelements ,asasubstituteforLa ,whiletheB5componentremainsprimar…  相似文献   

3.
1 Introduction ThestudyofB啨ziersurfaces’convexityisusefulinCAGD (computeraidedgeometricdesign)andtherehavebeenmanydiscussionsandresultsforthecon vexityoftheB啨ziersurfaceoveratriangle[1~ 6] .ButfortheconvexityoftheB啨ziersurfaceoverarectan gle ,whatweknewisli…  相似文献   

4.
1 Introduction Thesqueezingeffectofatomicdipolemomentisanimportantquantumeffectthatappearsininteractionbetweenatomandtheradiatedfield .Studiesonthisphenomenonisusefultocomprehendhowtorestrainthequantumnoiseofatom .Ithashighpotentialofap plicationsinopti…  相似文献   

5.
1 Introduction Thesuccessfulcommericalapplicationsofwirelesstechnologydemandappropriateantennas.Typically,adualpolarizationoperationsuchassimultaneousvertialandhorizontalpolarizationantennawithlowprofile,smallsize,andlightweightisrequiredforwidespre…  相似文献   

6.
现在 ,澳大利亚大约有 130 0个苗族人 ,(statis ticsinthisentryareestimatesmadebytheHmongcommu nity .The 1991censusconductedbytheAustralianBureauofStatisticsdidnotincludeanancestryquestion ,norwasHmongcodedasalanguage .ThustheAustralianHumongareconcealedamongstthestatisticsfor)是…  相似文献   

7.
1 Introduction TheKSequationinonespatialdimensionreadsas  ut+uxxxx+uxx+uux=0, x∈(-l2,l2),t>0,u(x,0)=u0(x).(1.1)Weemphasizethelperiodicboundarycondition,lbeingthesizeofatypicalpatterncell  u(x+l,t)=u(x,t).(1.2) TheKSequationarisesindifferentphysic…  相似文献   

8.
1 Introduction Squashmosaicvirus (SqMV)isoneofthemostim portantcucurbitviruses[1~ 3] ,anditcausesgreatlossesinmuskmelonproduction[4 ] .Oneofthemainwaystocontrolplantvirusdiseasesistheinducementofresis tancetoviruses[5] bysomebiologicalandnon biologicalfactors[6~ 9…  相似文献   

9.
1 Introduction Inecology ,apredator preyinteractionofbothpopu lationsinonedimensionisdescribedbythefollowingsystem[1] :ut(x ,t) =uxx uM (u ,v) ,vt(x ,t) =βvxx vN(u ,v) ,(1)whereβisapositiveconstant,uandvarethepreyandpredatordensitiesrespectively ,andthefunctionsMandNare…  相似文献   

10.
1 Introduction ThespatialGreen’sfunctionsofmulti layeredmediaareusefulinanalysisofantennaandintegratedcircuitstructures.Theyareconstructedintwosteps.ThefirstistoderivethespectralGreen’sfunction .ThesecondistomakeinverseFouriertransformoftheGreen’sfunc t…  相似文献   

11.
从功能梯度材料的弹性理论出发,首先推导出梯度材料在不同边界条件下的状态方程,进而使用Fourier变换技术将含裂纹弹性材料与梯度材料粘接的接触问题转化为边值问题,建立起该数学模型。构造带技巧性的积分变换方法将混合边值问题化为奇异积分方程,并利用Gauss—Chebyshev积分公式将奇异积分方程离散为计算机可实现的代数方程组,编制计算机程序并上机调试,得出数值模拟结果。  相似文献   

12.
为了减少预修正快速傅立叶变换算法(P-FFT)或拟合格林函数快速傅立叶变换算法(FG-FFT)的稀疏系数矩阵所需的存储空间,通过改进系数方程的求解方法,获得实系数解.并将改进的求解方法与P-FFT和FG-FF相结合用于计算电场积分方程.所提方案将P-FFT/FG-FFT的稀疏系数矩阵的存储量降到自适应积分方法(AIM)/积分方程快速傅立叶变换算法(IE-FFT)相同水平的同时,未增加矩阵向量积所需FFT的次数,并保持原有算法的精度水平.此外,在每次迭代的时间耗费方面,新方案与AIM/IE-FFT相当.数值实验证实了新方案的上述优点.  相似文献   

13.
利用离散的Fourier变换首次讨论了具有变系数和余割核奇异积分的卷积型方程的求解,并首先在L2[-π,π]上得到了可解条件和一般解.  相似文献   

14.
提出一种利用随机色样预测色设计心理评价的方法.通过对色样数据进行傅里叶交换分析,发现随机色样的心理评价不仅与基频分量相关而且与动态分量相关.最后对该评价方法的应用情况进行了讨论  相似文献   

15.
利用离散的Fourier变换首次讨论了含有H ilbert核和卷积核的若干类奇异积分方程的求解,并首先在L2[-aπ2,aπ2](a>0)上得到了可解条件和一般解。  相似文献   

16.
首先论述了基于小波变换的谐波检测的原理,根据目前小波变换在三相不对称系统谐波检测中存在的无法分离基波信号之不足,介绍了一种用于三相不对称系统的基于周期交错的测量方法。针对MRA算法既不能直接可靠地估算三相交流信号的基波成分(50 Hz),也不能精确地提取信号的谐波分量的缺点,探讨了将快速傅立叶变换和小波变换相结合的方法,利用小波变换的奇异信号检测能力和较好的时域分辨率,结合傅立叶变换准确的频域分辨能力对电网谐波信号模型进行了分析。文中归纳出基于小波变换的谐波监测方法。该方法的技术优势是可以实时跟踪谐波信号的变化。仿真实验结果表明了该方案能够满足电力系统中谐波检测的实时性要求。  相似文献   

17.
主要介绍采用动态扫频法测量了矩型谐振腔TE10P(p=1,2,3,4...)模式下,放入电、磁介质材料时腔的谐振频率f和Q值随p的变化。  相似文献   

18.
通过对付里叶变换积分性质的运用研究,指出付里叶变换微分性质运用时容易产生的错误;并提出确定冲激项存在与否的新途径,进而说明付里叶变换积分性质运用的广泛性,尤其对时间有限函数更为突出。  相似文献   

19.
In the last decade, a newmathematical microscope has allowed scientists and engineers to view the details of time varying and transient phenomena, in a manner hitherto not possible through conventionaltools. This invention, which goes by the name of wavelet transform, has created revolutionary changes in the areas of signal processing, image compression, not to speak about the basic sciences. This novel procedure enables one to achieve the so calledtime-frequency localization andmultiscale resolution, by suitably focussing and zooming around the neighborhood of one’s choice. Wavelets are of very recent origin; their construction, properties and applications are subjects of intense current research. In this article, we explain with illustrations the working of this transform and its advantages vis-a-vis the Fourier transform. In two companion articles, we describe the procedure to construct wavelet basis sets and their applications to data analysis and image compression.  相似文献   

20.
Ramanujan sums (RS) and their Fourier transforms have attracted more and more attention in signal processing in recent years. Due to their non-periodic and non-uniform spectrum, RS are widely used in low-frequency noise processing, Doppler spectrum estimation and time-frequency analysis. However, the traditional method for calculating RS values is rather complex since it requires two numbers' factorization in two arithmetic functions. For a length-n vector, its Ramanujan-Fourier transform usually involves a series of RS values which will occupy O(n2) memory units. Thus, in this paper an approach based on prime-composition is proposed to reduce the complexity of RS calculation to O(n). Meanwhile, the complexity of Ramanujan-Fourier transform can be further reduced from O(n2) to O(n In(In(n))) .  相似文献   

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