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1.
区间上三段单调扩张自映射的周期轨道   总被引:4,自引:0,他引:4  
孙太祥 《数学学报》1996,39(3):411-418
设n3是奇数,m0是整数,Sn及rn分别是方程xn-2xn-1-1=0及xn+2-3xn-x2-1=0的唯一正根,记tn0=rn,tni=sn(i1).又设f及g分别是闭区间I上的N型(即增-减-增型)及反N型(即减-增-减型)扩张自映射.本文证明了,若f(或g)的扩张常数或则f(或g)有2m·n周期点.此外,本文还指出,当或时,在[0,1]上存在着具有扩张常数λ却无2m·n周期轨道的N型(或反N型)扩张自映射.  相似文献   

2.
张桂宜  沈尧天 《数学学报》1998,41(4):851-858
本文给出RN(N3)中有界光滑区域Ω上的拟线性椭圆型方程:-∑Ni=1xi·|Du|p-2uxi=λ|u|p-2u+a(x)|u|p-2u+f(x,u),x∈Ω(λ>0,p=Np/(N-p),2p<N)在边界条件:-|Du|p-2Dνu|Ω=ψ(x)|u|q-2u(q=(N-1)p/(N-p))下的多解性结果.  相似文献   

3.
本文首先引入Besel(Riesz)位势K¨othe函数空间Xs(Xs)的概念,然后讨论一类算子在Lebesgue-位势K¨othe函数空间Lq(-T,T;Xs)上的对偶估计.由此我们得到半群exp(it(-Δ)m/2)和算子A:=∫t0exp(i(t-τ)(-Δ)m/2)·dτ在Lebesgue-Besov空间Lq-T,T;·Bsp,2中的一些时间--空间Lp-Lp′估计.本文的系列文将给出这些估计的应用  相似文献   

4.
Runge—Kutta方法的G—正交性   总被引:1,自引:0,他引:1  
1G-正交矩阵微分方程考虑RN×N上常微分矩阵方程初值问题这里W:[0,+∞)×RN×N→RN×N为一光滑的映射,Y(0)RN×N为给定的初值,G为实常正定矩阵.定义1.1如果问题(1.1)的真解y(t)满足YT(t)GY(t)=G,t≥0,则称该问题真解Y(t)是G-正交的,以下简称该问题是G-正交的.特别地,当G=IN时,称该问题是正交的,这里IN为N×N单位降.引理1.1[2]问题(1.1)是正交的当且仅当W(t,Y)=F(t,Y)Y,这里F;[0.+∞)×RN×N→N×N为一反对称矩阵函…  相似文献   

5.
1引言与预备知识 设X为一实赋范线性空间.X·是X的对偶空间,正规对偶映射J:X→2X定义为:其中<·,·>表示X和X的广义对偶组.由[1]知若X是一致光滑Banach空间,则J(·)单值且在X的任何有界子集上为一致连续.我们用j(·)表示单值的正规对偶映射. 定义1[2]设K是X的一非空子集,算子T:K→X称为是 -强伪压缩的,如果存在一个严格增加函数 ,存在使得 定义2[2,3]T称为 强增生算子的,如果(I-T)是 -强伪压缩算子(其中I是恒等算子). 若定义1(相应地;定义2)中 (t)=k…  相似文献   

6.
本文讨论了球上半线性椭圆Dirichlet问题Δu+λu+up=0正解的存在性,其中,λ∈R,0〈q〈1,p〉p≡(N+2)/(N-2)(N〉2).在条件N≤6或N〉6,p〈p≡(N+1-(2N-3)1/2)/(N-3-(2N-3)1/2)下,证明了存在唯一的λ00〉0,当λ=λ0时,有唯一的径向奇异解及无穷多个正解。  相似文献   

7.
数学问题解答1994年3月号问题解答(解答由问题提供人给出)881求方程的一个正整数解.x2y3z5解原方程即为即1994·1995n+1995n=1995n+1.由1994·1995-5+1995-6=1995-5,即1994.(1995a)-2+...  相似文献   

8.
郭占宽  孙炯 《数学学报》2000,43(6):1031-104
本文研究了一类具有中间亏指数的正系数的对称微分算式=0(-1)kDkeanxDk及=0(-1)kakDkeanxDk,证明了它们的亏指数的值域是(n,n+2,…,2n-1)或{n,n+ 2,…,2n-2 },或是一个子集合,并给出了具中间亏指数的算式的例子·这些例子表明具正系数的对称微分算式不一定都是极限点的,从而对 Everitt W. N.[1]提出的猜测又以一种新的方式给出了否定的回答.本文还得到了一类非对称的微分算式一些相应的结果.  相似文献   

9.
线性流形上的矩阵最佳逼近   总被引:8,自引:1,他引:7  
令S={A∈Rn×m|f1(A)=‖AX1-Z1‖2+‖YT1A-WT1‖2=min},其中X1∈Rm×k1,Z1∈Rn×k1,Y1∈Rn×11和W1∈Rm×11均为给定的矩阵,‖·‖是Frobenius范数。本文考虑如下问题:问题Ⅰ给定X2∈Rm×k2,Z2∈Rn×k2,Y2∈Rn×l2,W2∈Rm×l2,求A∈S,使得f2(A)=‖AX2-Z2‖2+‖YT2A-WT2‖2=min.问题Ⅱ给定A∈Rn×m,求A∈SA,使得‖A-A‖=infA∈SA‖A-A‖,其中SA是问题I的解集合。本文给出问题I解集合SA的通式和问题Ⅱ的解A的表达式,提出了求解问题Ⅰ与Ⅱ的数值方法。许多文献的结果都是本文结果的特例。  相似文献   

10.
GL(n,Z)中的局部有限子群的一点注记   总被引:1,自引:0,他引:1  
证明了:若G是一般线性群GL(n,Z)中的局部有限子群,则G含有一个2~m阶的初等阿贝尔2-子群,且 G同构于 GL(n,Z_p)的一个子群,其中户为任意奇素数.当 n=1,2,3,4时,G的阶分别是 2,3· 2~k(k=min(4,m+1),0≤m≤4),3·2~k(k=min{5,m+1},0≤m≤5),3~2·5·2~k(k=min{9,m+6},0≤m≤9)的一个因子,而当n≥5时,G的阶是(p~i-1)的一个因子,其中p为任意素数.  相似文献   

11.
周学光 《数学学报》1958,8(2):200-209
<正> 在[1]中,作者研究了一个(N—1)维连通空间的同伦群和同调群的密切关系,那里所考虑的同伦群的维数是在(2N—2)以内,本文可以看成[1]的继续,我偿将考虑维数在(2N—1)以上而又在(3N—3)以下的同伦群,Betti 数;和上乘积的密切关系.我们  相似文献   

12.
The time series of yearly occurrence frequency of cyclonic disturbances over the Indian region for 1891–1970 is subjected to power spectrum analysis by the maximum entropy method (MEM) of Burg. Earlier analyses by the conventional Blackman-Tukey method had indicated periodicities atT= 2·3-2·5, 5 and 30–45 years at about 90–95% significance level. The present analysis shows peaks atT = 1·2, 2·4, 2·9, 3·7, 4·7, 6·4, 7·4, 9·2, 10·5, 20 and 40–60 years but the significance level may not be better than the earlier method. When data are analysed separately for first half and latter half, periodicities observed are quite different, the earlier half revealingT= 1· 2, 2·3, 2·9, 4·7, 9·0 and 23 years and the latter half revealingT= 1·2, 2·1, 2·4, 3·8, 6·7 and 21 years. Thus, a change of pattern before and after about 1920 is indicated. However, the power in the various peaks is small and a random origin cannot be ruled out. An analysis of several artificially produced samples of pseudo-Gaussian random white noise of the same mean, standard deviation and length (80 values) as the above physical samples indicated that similar peaks could occur by pure chance also. Physically, T=l·2 years corresponds to the Chandler’s wobble and other peaks could be harmonics of the sunspot cycleT= 11 years or double sunspot cycleT = 22 years. However, no peak is noticed at or nearT= 11 years whereasT near 22 years is noticed.  相似文献   

13.
Interactions of compounds containing OH group with acrylonitrile, 2 : 3 dichloropropene, allyl cyanide and allyl halides have been studied using NMR and IR techniques. Hydrogen bonds of the type O-H ··· N have been detected. With allyl halides bonds of the type O-H ··· Cl have been detected for allyl chloride only. The value of the equilibrium constant has been calculated for O-H ··· N bonds using IR studies.  相似文献   

14.
Let |·| be a fixed absolute norm onR 2. We introduce semi-|·|-summands (resp. |·|-summands) as a natural extension of semi-L-summands (resp.L-summands). We prove that the following statements are equivalent. (i) Every semi-|·|-summand is a |·|-summand, (ii) (1, 0) is not a vertex of the closed unit ball ofR 2 with the norm |·|. In particular semi-L p-summands areL p-summands whenever 1<p≦∞. The concept of semi-|·|-ideal (resp. |·|-ideal) is introduced in order to extend the one of semi-M-ideal (resp.M-ideal). The following statements are shown to be equivalent. (i) Every semi-|·|-ideal is a |·|-ideal, (ii) every |·|-ideal is a |·|-summand, (iii) (0, 1) is an extreme point of the closed unit ball ofR 2 with the norm |·|. From semi-|·|-ideals we define semi-|·|-idealoids in the same way as semi-|·|-ideals arise from semi-|·|-summands. Proper semi-|·|-idealoids are those which are neither semi-|·|-summands nor semi-|·|-ideals. We prove that there is a proper semi-|·|-idealoid if and only if (1, 0) is a vertex and (0, 1) is not an extreme point of the closed unit ball ofR 2 with the norm |·|. So there are no proper semi-L p-idealoids. The paper concludes by showing thatw*-closed semi-|·|-idealoids in a dual Banach space are semi-|·|-summands, so no new concept appears by predualization of semi-|·|-idealoids.  相似文献   

15.
The flux of He3 nuclei and the ratio He3/(He3+He4) in the low energy primary cosmic radiation have been determined using a stack of nuclear emulsions exposed at 3·1 g. cm.?2 of atmospheric depth from Fort Churchill, Canada, in June 1963. The grain-densityversus residual range method was used to determine the masses of the helium nuclei. Using a sample of 146 helium nuclei whose masses could be identified, the ratio He3/(He3+He4) is obtained as 0·14±0·04 for the kinetic energy interval 115–210 MeV per nucleon and 0·43±0·11 for the rigidity interval 0·85–1·05 BV. The differential fluxes of He3 nuclei are determined as 0·017±0·006, 0·045±0·015, and 0·054±0·017 particles/M2. Sr. Sec. MeV/nucleon, in the kinetic energy intervals of 117–183, 183–217, and 217–250 MeV/nucleon respectively. These results are compared with those of other investigators. From the results of the present work the amount of matter traversed in space by the primary cosmic ray helium nuclei of energy 115–210 MeV/nucleon is obtained as 4·7±1·8 gm. cm.?2 of hydrogen.  相似文献   

16.
2′-Hydroxy chalcone gave an intense orange-yellow color with beryllium in the pH range 5·5–6·2. The limits of identification and dilution were 0·125γ and 1:4 × 105 respectively. A detailed spectro-photometric investigation of the color reaction was carried out. The complex obeyed Beer’s Law in the concentration range of 0·5–6·0p.p.m. at 460 nm. In the complex the ratio of metal to ligand is 1:2. The instability constant of the complex was 2·176 × 10?6 at 28°. Oxalate, tartrate, citrate and fluoride interfered. The tolerance limits of iron, aluminium, chromium, uranium, thorium and vanadium are reported.  相似文献   

17.
A nuclear emulsion stack was exposed over Hyderabad, India (geomagnetic latitudeλ=7·6° N) under a mean atmospheric depth of 6·8 g./cm.2, on 24 March 1960. The relative and absolute intensities of Be and B nuclei and nuclei of charge Z?6 (the S-nuclei) have been determined in this stack. The intensities were extrapolated to the top of the atmosphere using measured fragmentation parameters involved in collisions of cosmic ray nuclei in graphite. The flux values of Be, B and S nuclei at the top of the atmosphere have been determined to be 0·025±0·011, 0·101±0·023 and 1·12±0·10 particles/m.2 sec. sr. respectively. The ratios of intensities B/S, Be/S and Be/B have been found to be 0·09±0·02, 0·022±0·008 and 0·25±0·11 respectively. These ratios of intensities have been used (a) to compute the amount of matter traversed by the radiation before reaching the vicinity of the earth as 2·6±0·6 g./cm.2, (b) to show that the Fermi mechanism of acceleration of particles is not efficient at these energies (1–10 GeV/n.) in interstellar space and (c) to show that preferential acceleration of H1-nuclei (Z?20) is not of overwhelming importance. The derived source composition of nuclei of energy ?7·5 GeV/n suggests that N, O, F and H3-nuclei (Z=10–15) have similar abundances in the universe and in cosmic rays, and that C and H1-nuclei are overabundant in cosmic rays.  相似文献   

18.
对任意正整数n,Smarandache函数U(n)、V(n)定义为:U(1)=V(1)=1,n>1时,若它的标准分解式是n=p_1~(α_1)p_2~(α_2)…p_r~(α_r),U(n)=1{α_1·p_1α_2·p_2,…,α_r·p_r};V(n)={α_1·p_1,α_2·p_2,…,α_r·p_r}.研究了这两Smarandache函数U(n)与V~m(n)的值分布,并用初等方法及素数分布定理得到了几个较强的渐近公式.  相似文献   

19.
The stability constants of methionine complexes of cadmium were determined polarographically by ths method of DeFord and Hume as β1 =6·5 × 103, β2 = 1·7 × 106 and β3 = 2·1 · 108. The indium complexes were studied by the modified method of Momoki and Ogawa and two complexes, with β1 = 1·7 × 108 and β2 = 8·4 × 1013, were identified in the concentration range studied. The haf-wave potential of uncomplexed indium ion which cannot be measured directly owing to the irreversible nature of the reduction was calculated as — 0·503 Vvs. SCE.  相似文献   

20.
The standard heats of combustion of the disubstituted ureas, N, N′-diheptyl urea, N, N′-dioctyl urea and N, N′-didecyl urea and the carbamates,n-heptyl ammoniumn-heptyl carbamate,n-octylammoniumn-octyl carbamate andn-decyl ammoniumn-decyl carbamate have been determined. The values found are 2353±1·3, 2658·4±1·1, 3268·5±1·7, 2349·8±1·6, 2654·4±1·2, 3264·6±1·8, K.cals. mole?1 respectively. The heats of formation of these compounds have been calculated.  相似文献   

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