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1.
讨论了三角多项式内插基函数的若干性质。当取样点具有特殊分布时,采用三角多项式内插法可精确重构原周期带限信号。给出了用于有限样点加密的内插公式。  相似文献   

2.
设{X(t),T1≤t≤T2}是一可分、可测的高斯过程,其协方差函数具有连续一阶偏导,方差函数在(T1,T2)内具有有限个局部极大点.考虑在高水平u之上X(t)的逗留时间的渐近分布,在一定的条件下得到极限形式为有限个积分之和的结论.  相似文献   

3.
非保守Duffing方程周期解的存在唯一定理   总被引:4,自引:1,他引:3  
讨论非保守的 Duffing 方程 x″( t) + cx′( t) + g( t ,x) = e( t) 的2π周期解,利用 Poincare 扰动方法,在渐近非一致条件γ(t) ≤gx( t,x) ≤Γ( t) ,γ,Γ∈ L1(0 ,2 π) ,γ,Γ满足可跨0 特征值,得到所讨论方程2π周期解存在唯一的一个定理  相似文献   

4.
利用Fourier级数理论研究了单时滞具临界常系数线性中立型方程d^2dt^2x(t)+a1ddtx(t)+a2x(t)+cd^2dt^2x(t-h)+c1ddtx(t-h)+c2x(t-h)=f(t)的周期解的存在性、唯一性问题,其中h≥0,│c│=1,ai,ci(i=1,2)为常数,f(t)是连续可微的以2π为周期的函数。在一定条件下,如果f(t)足够光滑,那么上述方程的周期解存在且唯一。  相似文献   

5.
在最佳逼近多项式的基础上提出了最佳逼近序列的定义,并通过将多分辨分析中的尺度函数转化为取样定理中的基函数,讨论了Bmπ-频谱有限函数空间中最佳逼近序列的一种计算方法.  相似文献   

6.
一类拟线性第二边值问题的存在唯一性   总被引:1,自引:0,他引:1  
本文在f(t,x),fx(t,x),β(t)连续,fx(t,x)≥-β(t),β(t)≤π20+α24,β(t)π20+α24,π0为方程αsinx2+xcosx2=0的最小正根条件下,证明了第二边值问题.x"=αx+f(t,x),x(0)=a,x(1)=b对于任给实数α,a,b都有唯一解  相似文献   

7.
研究了目标函数的系数为变量的线性规划(即多维参数规划)问题,判断了在一定条件下其最优解的存在性,并给出了求其最优解的一种方法,证明了当F(x,t)关于t线性且minx∈XF(x,t)(t∈T)一致非退化时,minx∈XF(x,t)(t∈T)的最优解为有限个一般线性规划最优解的最小值。  相似文献   

8.
该文导出了两维四节点和三维八节点Lasrange线性内插函数、适用于编程和计算的实用表示式,并给出其在时域有限差分法(FD-TD)计算角点辐射边界条件(RBC)中的推广应用.  相似文献   

9.
提出了处理奇异积分方程(a(t)ψ(t)+b(t)/π∫^1-1ψ(τ)/τ-tdτ=f(t),-1<t<1中b(t)不是多项式情况下求其数值解的一种有效方法,改进了现胡文献的一些附加条件。  相似文献   

10.
考虑随机系数代数方程Fn(w,t)=0(w)+1(w)t+…+n-1(w)tn-1=0,其中i(w)(i=0,1,…,n-1)为独立且服从标准正态分布的随机变量。令ENF(w)表示Fn(w,t)的平均实根个数。本文证明了ENF(w)<2πlnn-2nπ+1.2372771。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
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。  相似文献   

20.
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.  相似文献   

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