关于LCM方程的李-曹猜想的注记

在研究Hong关于定义在gcd封闭集上的幂LCM矩阵［Se］(e为正整数)的非奇异性的一个猜想时,李和曹研究了如下的不定方程(称为LCM方程)：1lcmy1,y2,y3,y4-4i=11yi+1gcd(y1,y2)+1gcd(y1,y3)+1gcd(y2,y3)[SX)]=0.他们首先证明了当ω(y)＜4时,方程无解,这里y=lcm［y1,y2,y3,y4］,ω(y)表示y的不同素因子的个数;然后他们给出ω(y)=4且y=p21p22p23p2m4时,方程有2次幂整数解的必要条件,这里pi为不同素数,m≥1;根据这些必要条件他们接着验证了方程当y≤1 334 025时没有2次幂整数解;最后他们提出猜想：若n≤9,则定义在gcd封闭集S={x1,…,xn}上的平方LCM矩阵［S2］是非奇异的,即LCM方程没有2次幂整数解.本文作者推广了李-曹关于LCM方程有2次幂整数解的研究：首先给出了当ω(y)=4且y=p2m11p2m22p2m33p2m44时,方程有2次幂整数解的必要条件,并给出了当ω(y)≥4时,方程解的表达式(如果存在的话),这里pi为不同素数,mi≥1;然后根据这些必要条件在计算机上验证了方程当y≤260 620 460 100时没有2次幂整数解,进一步支持了李-曹猜想.     

关于不定方程4x~2-py~2=1

研究了二次不定方程4x2-py2=1(p为奇素数),对于特例p=m2±2(m为正奇数),利用Pell方程x2-py2=1的正整数解公式得到了原方程的所有正整数解.另外还证明了p=1,5(mod8)时方程4x2-py2=1无正整数解.     

关于Tijdeman猜想(Ⅱ)

1989年Tijdeman猜想设a,b,c是互素的正整数,m,n,r是大于1的正整数,则方程ax m+by n=cz r在1/m+1/n+1/r<1时仅有有限多组整数解;本文利用数论方法及Fermat无穷递降法,证明了丢番图方程x 8+my 4=z 2在m=±p,±2p,±4p,±8p及素数p满足一定条件下无正整数解,完善了Mordell等人的结果;并且获得了方程x 4-2py 4=z 2和x 4+8py 4=z 2的无穷多组正整数解的通解公式,从而获得了Tijdeman猜想与广义Fermat猜想的研究进展.     

关于丢番图方程x3±1=py2

应用因子分解法、简单同余法以及前人的已知结果证明了:(1)设p是1个奇素数,则丢番图方程组x+1=3py21,x2-x+1=3y22,(y1,y2)=1,y1>0,y2>0,无正整数解x,p,y1,y2;(2)丢番图方程x3+1=py2(其中p≡-1(mod 3)为素数)仅有整数解(x,y)=(-1,0);(3)丢番图方程x3-1=py2(其中p≡-1(m od 3)为素数)仅有整数解(x,y)=(1,0).     

方程φ(n)=2tw(n)(t∈Z+)的解

利用初等方法研究了方程φ(n)=2tw(n)(t∈Z+)的可解性,给出了两个平凡解和其它一般解必有形式n=2mp1p2…pk(m≥0,k≥1,p1相似文献   

方程xp±y2p=z2与广义费尔马猜想

设p为奇素数,证明了丢番图方程x4 -y4 =zp 与x2p±y2p=z2 均无正整数解;方程xp y2p=z2 仅有整数解 16 2 3 =32 ;方程x2p 2 kyp =z2 (k≥ 1)仅有整数解 12p 2 3 · 1p =32 ;同时还获得了方程x2 ±y4 =zp与x2 ±y4 =±z2p 的深刻结果,从而很大程度地支持广义Fermat猜想.     

关于丢番图方程2py~2=2x~3+3x~2+x的解

本文运用初等数论简单同余法、分解因子法及反证法等,得到丢番图方程2py2=2x3+3x2+x,(p为素数)无正整数解的情况.(1)当p≡1(mod 8),p≡5(mod 8),p≡7(mod 8)时,则方程无正整数解;(2)当p≡3(mod 8)时,Un+Vnp(1/2)=(x0+y0p(1/2))n.其中x0,y0是Pell方程x2-py2=1的基本解,当n≡0(mod 2)时,则方程无整数解;当n≡1(mod 2)时,若2|x0,则方程无整数解.特别是p≡3(mod 8)且p100时,2|x0,则方程无整数解.     

关于不定方程∏nk=1(k2+1)=a·m2的探讨

对于不定方程∏nk=1(k2+1)=a·m2,J. Cilleruelo证明了当a=1时,当且仅当n=3方程有解.证明了当a=5和7时,此方程无解;当a=17时,方程只有唯一解;还证明了一般情形,当a满足(a,17×101×1 297×739 601)=1且a的最大素因子p(a)≤2×738 740时,当n>3,方程无解.     

关于Diophantine方程x^p-2^mp=pDy^2

设p是奇素数,m是正整数.D是无平方因子正整数.本文证明了当p＞3,m＞1,D不能被p或2kp+1之形素数整除时,方程xp-2mp=pDy2没有适合gcd(x,y)=1的正整数解(x,y).     

关于丢番图方程p~2-2q~2=-1

Berger在关于有限群的工作中提出了丢番图方程p~m-2q~n=±,p.q素数,m>1,n>1.(1)Grescenzo在1975年对此进行了研究。并问:是否存在无穷多对素数(p.q)适合p~2-2q~2=±1,p.q素数 (2)对于方程p~2-2q~2=1.模4立刻得到该方程有唯一素数解p=3.q=2。困难的是丢番图方程p~2-2q~2=-1,p.q素数 (3)对于方程(3),目前还没有什么结果。本文通过研究pell数的性质,得到一糸列(2)有解的必要条件     

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.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.