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1.
针对GM(1,1)模型预测估计值稳定性差等问题,从灰色建模基本要求出发,给出了一种新的GM(1,1)模型参数估计方法。与原方法相比,新方法参数估计值稳定性强,误差小,达到了理想的预测效果。  相似文献   

2.
对最优化方法中的梯度算法进行了改进,当e^2f/ex^2≠0时,将二阶导数与梯度方向相结合,构造出一种新的下降方向d=「1+δ/(e^2f/ex^2)」(ef/ex),其中δ=1或-1,用新的下降方向设计了一种算法,使梯度法得到改进,新的算法比梯度法的收敛速度快,而且比牛顿法计算量小。  相似文献   

3.
一种新的奇阶幻方的公式构造法   总被引:2,自引:0,他引:2  
用公式的方法构造了一种新的奇阶幻方,并且给出了构造2n+1阶幻方(n〉1)的严密证明,最后给出了9阶幻方的实例。  相似文献   

4.
1新的VN表达式的又一个应用1.1过去的VN表示式设有一图1所示的多级火箭,Wi为该火箭第i级的喷气速度,M(1)i为第i子火箭在第i级点火时的质量,M(2)i为第i子火箭在第i级关机时的质量,G为该火箭的有效载荷,ri为质量比ri=M(1)iM(2...  相似文献   

5.
提供一种新的方法研究问题(1)解的存在性,在此对k(x)x的限制要比已有文献弱。  相似文献   

6.
提供一种新的方法研究问题(1)解的存在性,在此对k(x)的限制要比已有文献弱。  相似文献   

7.
Behzad〔1〕和Vizing〔2〕独立提出了全色数精想:对任意图G,有xT(G)≤Δ(G)+2。本文的主要结果如下:(1)用一种新的方法证明了完全多部图满足全色猜想(2)证明了点数不大于10的图满足全色数猜想。  相似文献   

8.
对分子格L上的自映射f:L→L,提出了一种新的映射道f-1:L→L,其中,对任意L中的元a,f-1(a)=∨{b∈M(L)|a∧f(b)≠0}.借助于此,引入了分子格上的一种对称的一致结构,证明了一个拓扑分子格(L,η)可一致化当且仅当它是全正则分子格.  相似文献   

9.
用一种新的三氮烯类显色剂,1-(4-磺基苯)-3-(2-噻唑)-三氮烯(SPTT)的合成方法,探讨试剂的分析性能,着重研究了试剂与钯(Ⅱ)的显色反应条件。  相似文献   

10.
根据1960-1995年间渤海海域的海冰灾害的实际观测资料,建立了信息GM(1,1)模型,并在此基础上又分别对GM(1,1)灰色预测模型提出新的改进型预测模型,并运用改进型的预测模型对渤海海域的海冰严重灾害进行预测,据预测未来可能发生的两次海冰严重灾害为2003年和2011年。  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.
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   

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 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   

15.
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   

16.
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.  相似文献   

17.
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   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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