开源软件服务提供商的市场策略及社区参与策略研究

开源软件由开源社区内的成员自发参与并协同完成开发,是一种高效的、有别于传统的软件生产模式。开源社区的主要成员有软件用户及开源软件服务提供商。本文通过构建三阶段模型,研究了服务提供商的市场策略及开源社区内用户创新对服务提供商参与策略的影响。研究发现:(1)若市场上高价值用户较少,服务提供商应采取低质量、低价格的市场策略,否则应采取高质量、高价格策略。(2)服务提供商要避免搭便车行为,即为了增加服务利润,它必须投入资源参与开源社区、提高软件质量。(3)当服务市场上目标用户较多且开源社区内用户参与动机较强时,服务提供商应采取高参与策略,否则采取低参与策略。本文的研究对服务提供商如何利用和参与开源社区具有指导意义。     

KKM mappings in cone metric spaces and some fixed point theorems

In this paper, we define KKM mappings in cone metric spaces and define Nℜ-cone metric spaces to obtain some fixed point theorems and hence generalize the results obtained in [A. Amini, M. Fakhar, J. Zafarani, KKM mapping in metric spaces, Nonlinear Anal. 60 (2005) 1045-1052].     

Weakly open sets in the unit ball of some Banach spaces and the centralizer

We show that every Banach space X whose centralizer is infinite-dimensional satisfies that every non-empty weakly open set in BY has diameter 2, where (N-fold symmetric projective tensor product of X, endowed with the symmetric projective norm), for every natural number N. We provide examples where the above conclusion holds that includes some spaces of operators and infinite-dimensional C^∗-algebras. We also prove that every non-empty weak^∗ open set in the unit ball of the space of N-homogeneous and integral polynomials on X has diameter two, for every natural number N, whenever the Cunningham algebra of X is infinite-dimensional. Here we consider the space of N-homogeneous integral polynomials as the dual of the space (N-fold symmetric injective tensor product of X, endowed with the symmetric injective norm). For instance, every infinite-dimensional L₁(μ) satisfies that its Cunningham algebra is infinite-dimensional. We obtain the same result for every non-reflexive L-embedded space, and so for every predual of an infinite-dimensional von Neumann algebra.     

I-fuzzy拓扑中的正则开集

在I-fuzzy拓扑空间框架下引入了I-fuzzy正则开集和某个模糊点的I-fuzzy正则R-邻域系的概念,进一步,又给出了I-fuzzyδ-闭包、I-fuzzyδ-开集等概念,且分别研究了它们的基本性质.     

关于开区间内连续函数最值的判定

由闭区间上连续函数的最值存在定理,讨论开区间内连续函数最值的存在性,并得出几个结论.     

Entanglement dynamics for the double Tavis-Cummings model

A double Tavis-Cummings model (DTCM) is developed to simulate the entanglement dynamics of realistic quantum information processing where two entangled atom-pairs AB and CD are distributed in such a way that atoms AC are embedded in a cavity a while BD are located in another remote cavity b. The evolutions of different types of initially shared entanglement of atoms are studied under various initial states of cavity fields. The results obtained in the DTCM are compared with that obtained in the double Jaynes-Cummings model (DJCM) [M. Yönaç, T. Yu, J.H. Eberly, J. Phys. B 40, S45 (2007)] and an interaction strength theory is proposed to explain the parameter domain in which the so-called entanglement sudden death occurs for both the DTCM and DJCM.     

Spatial decoherence factor via the qubit-field interaction

We analyze the time evolution of an initial spatial coherence for a two level atom whose internal degrees of freedom interact with a single mode of a cavity field. When the qubit-field subsystem is taken as an environment, the translational dynamics experiences a decoherence process which may be encoded in a decoherence factor D. We find that the field statistics affects D through the alternative paths the system-environment may follow along their entanglement, while eventual field phase properties give rise to an imaginary part of D which is related to the atomic translation. From the decoherence perspective, we analyze the relation between the atomic momentum and the imaginary part of the atomic spatial density matrix, and some considerations on its asymptotic behavior are brought into question at the conclusion of the paper.     

设放性物理实验项目培养大学生科研创新能力简

开设开放性大学物理实验是培养大学生科研创新能力的重要途径，是提高各类专业人才素质的主要途径。文章介绍兰州城市学院开放性大学物理实验项目的实践情况，阐述开设开放性大学物理实验项目的重要性和取得的成效。     

Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography

Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L⁻¹ levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min⁻¹, and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L⁻¹ for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%.     

互联网上的开放大学物理教育

对互联网上的开放物理教育进行了研究.给出了网络学习系统组成、免费物理课程资源;对物理开放课程做了统计分析;将网络免费物理学习方式与其他教育模式进行对比;展望互联网物理教育未来发展趋势.