This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the relationships between the d...This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the relationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree.展开更多
琼东南盆地属于中孔低渗储层,储层易发生水化、水锁等伤害。当前区块系列井所用深水钻井液侵入损害类型、机理不明,且传统的钻井液伤害评价方法误差大,不能直观地量化损害程度。因此设计了以钻井液污染实验、扫描电子显微镜(scanning el...琼东南盆地属于中孔低渗储层,储层易发生水化、水锁等伤害。当前区块系列井所用深水钻井液侵入损害类型、机理不明,且传统的钻井液伤害评价方法误差大,不能直观地量化损害程度。因此设计了以钻井液污染实验、扫描电子显微镜(scanning electron microscope,SEM)分析、计算机断层扫描(computed tomography,CT)结合的方式分析钻井液固相以及液相侵入损害储层的方法。结果表明,深水钻井液与地层水配伍性良好,储层水锁损害率处于19.8%~31.4%,液相侵入损害主要为水锁损害;岩心SEM扫描结果显示其孔隙连通性差,EDS测试结果中Ba^(2+)、Ca^(2+)含量较高,分析固相侵入损害主要由加重剂引起,且蒸馏水返排后岩心CT扫描结果显示孔隙度微幅上升表明固相堵塞很难通过自然返排的方式清除。于是通过研发降滤失剂和优选加重剂粒径配比的手段优化深水钻井液储层保护性能。根据理想充填理论,确定最佳配比为1000目CaCO_(3)、600目CaCO_(3)和200目CaCO_(3)的比例为5∶11∶9。优化后体系滤失量显著降低,固相颗粒中径在90μm左右,滤饼致密程度明显提高;渗透率恢复值提高12.1%~19.68%,对该区块钻井液储层保护性能优化具有指导意义。展开更多
In this paper,we study the completely monotonic property of two functions involving the functionΔ(x)=[ψ′(x)]2+ψ″(x)and deduce the double inequality x^(2)+3x+3/3x^(4)(2x+1)^(2)<Δ(x)<625x^(2)+2275x+5043/3x^(...In this paper,we study the completely monotonic property of two functions involving the functionΔ(x)=[ψ′(x)]2+ψ″(x)and deduce the double inequality x^(2)+3x+3/3x^(4)(2x+1)^(2)<Δ(x)<625x^(2)+2275x+5043/3x^(4)(50x+41)^(2),x>0which improve some recent results,whereψ(x)is the logarithmic derivative of the Gamma function.Also,we deduce the completely monotonic degree of a function involvingψ′(x).展开更多
Let G be a maximal outerplane graph and X0(G) the complete chromatic number of G. This paper determines exactly X0(G) for △(G)≠5 and proves 6≤X0.(G)≤7 for △(G) = 5, where △(G) is the maximum degree of vertices o...Let G be a maximal outerplane graph and X0(G) the complete chromatic number of G. This paper determines exactly X0(G) for △(G)≠5 and proves 6≤X0.(G)≤7 for △(G) = 5, where △(G) is the maximum degree of vertices of G.展开更多
基金Supported by the National Key Basic Research Program of China(No.2013CB834204)
文摘This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the relationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree.
文摘琼东南盆地属于中孔低渗储层,储层易发生水化、水锁等伤害。当前区块系列井所用深水钻井液侵入损害类型、机理不明,且传统的钻井液伤害评价方法误差大,不能直观地量化损害程度。因此设计了以钻井液污染实验、扫描电子显微镜(scanning electron microscope,SEM)分析、计算机断层扫描(computed tomography,CT)结合的方式分析钻井液固相以及液相侵入损害储层的方法。结果表明,深水钻井液与地层水配伍性良好,储层水锁损害率处于19.8%~31.4%,液相侵入损害主要为水锁损害;岩心SEM扫描结果显示其孔隙连通性差,EDS测试结果中Ba^(2+)、Ca^(2+)含量较高,分析固相侵入损害主要由加重剂引起,且蒸馏水返排后岩心CT扫描结果显示孔隙度微幅上升表明固相堵塞很难通过自然返排的方式清除。于是通过研发降滤失剂和优选加重剂粒径配比的手段优化深水钻井液储层保护性能。根据理想充填理论,确定最佳配比为1000目CaCO_(3)、600目CaCO_(3)和200目CaCO_(3)的比例为5∶11∶9。优化后体系滤失量显著降低,固相颗粒中径在90μm左右,滤饼致密程度明显提高;渗透率恢复值提高12.1%~19.68%,对该区块钻井液储层保护性能优化具有指导意义。
文摘In this paper,we study the completely monotonic property of two functions involving the functionΔ(x)=[ψ′(x)]2+ψ″(x)and deduce the double inequality x^(2)+3x+3/3x^(4)(2x+1)^(2)<Δ(x)<625x^(2)+2275x+5043/3x^(4)(50x+41)^(2),x>0which improve some recent results,whereψ(x)is the logarithmic derivative of the Gamma function.Also,we deduce the completely monotonic degree of a function involvingψ′(x).
基金Project supported by the Vatural SCience Foundation of LNEC.
文摘Let G be a maximal outerplane graph and X0(G) the complete chromatic number of G. This paper determines exactly X0(G) for △(G)≠5 and proves 6≤X0.(G)≤7 for △(G) = 5, where △(G) is the maximum degree of vertices of G.
