科学松鼠会的传播内容偏向和受众关注偏向的调查研究

通过对科学松鼠会微博、博客、网站的内容和受众关注内容的主题分类进行统计分析,发现两者都偏向关注生物、健康、医学等类别,即传播内容的偏向与受众关注的偏向具有一致性。同时,通过对科学松鼠会主编"游识猷"(网名)的采访调查和对其微博粉丝的问卷调查,深入分析科学松鼠会的传播者和受传者分别在各自偏向的形成过程中所起的作用,以及这两种偏向的关系,并为其他综合性科普网站提供一定的借鉴。     

元素俘获测井在库车深层致密砂岩中的应用

库车前陆盆地深层砂岩气藏表现为低孔隙度特低渗透率特征,由于钻井取心少,评价复杂岩性储层存在困难。元素俘获测井(ECS)利用矿物成分获取地层岩性和骨架参数,能够指导评价复杂岩性地层。利用元素俘获测井获取的元素干重百分比,建立反演矿物模型求取矿物的含量。用ECS测井资料获得的矿物含量计算地层变骨架密度(地层骨架密度随深度变化而变化),再计算地层孔隙度,其孔隙度结果与岩心孔隙度基本吻合,验证了ECS测井技术求取地层孔隙度方法的可靠性。对库车前陆盆地深层7口井已知数据的验证,提高了地层孔隙度的解释精度。实践表明,ECS测井技术用于求取塔里木盆地库车深层致密砂岩地层中的储层参数,取得了很好的应用效果。     

含水对普光酸性气田流体物性的影响

为了确定酸性气藏含水是否对其流体物性有影响,笔者通过对普光酸性气田的气样配置了相应的实验无水气样和含水气样,并进行了无水酸性气体和含水酸性气体PVT实验研究。实验结果表明：酸性气体含水对气体偏差因子无影响,而对气体黏度有较大影响,主要表现在低压（<40MPa）条件下。温度对酸性气体的含水量、黏度、偏差因子影响较小。同一压力条件下,温度越高,酸性气体中所含水量越大,气体黏度越小。一定温度,低压条件下,压力升高,气体含水量急剧下降,含水酸性气体黏度减小的程度明显高于未含水酸性气体黏度减小的程度;高压（>40MPa）条件下,压力的升高,酸性气体的含水对其黏度影响较小。     

Model for the oxygenation of the YBa2Cu3O7−x 90K superconductor

A model incorporating the thermodynamic equilibrium oxygen content, oxygen in-diffusion, and oxide phases for the oxygenation of the YBa₂Cu₃O_7−x is described. For sintered polycrystals, grain growth and the resulting grain size distribution are included. The model is used to calculate the volume percent of each oxide phase for several processing conditions of sintered specimens and is compared with available results on the quantification of phases present. Such a comparison indicates that as the concentration of impurity phases increases so does the concentration of the less oxygenated 123 phases, suggesting that impurities coating 123 grains act as oxygen indiffusion barriers. The model is also used to investigate the uniformity of the oxygen content in large twinned and detwinned single crystals such as have been used for measuring superconductivity parameters.     

Chemistry of electron doped Ln2−xCexCuO4 superconductors

The electron doped Ln_2−xCe_xCuO₄ (Ln=lanthanide) oxides have intergrowth structures consisting of superconductively active CuO₂ sheets alternating with inactive (Ln, Ce)₂O₂ fluorite layers along the c-axis. Stabilization of such intergrowth structures requires bond length matching across the intergrowth interface. The bond length matching criterion causes a monotonic decrease in the Ce solubility limit from x=0.24 to x=0.15 as the size of Ln³⁺ decreased from Ln=La_0.5Nd_0.5 to Ln=Gd. Annealing in N₂ atm of Ln_2−xCe_xCuO₄ at temperatures above 900°C creates oxygen vacancies and the number of vacancies decreases with increasing Ce content. The value of x at which a semiconductor to superconductor transition occurs in Ln_2−xCe_xCuO₄ increases with decreasing size of Ln³⁺ due to an increasing Madelung energy caused by a decreasing Cu−O bond length.     

金属卤化物气体放电灯启动问题的探讨

本文介绍了分别改变灯内填充物含量即 NaI 和 ScI 含量的方法,探讨此变化与光源气体放电参数的关系,从而分析和研究金属卤化物灯的启动特性,从而寻求延长光源寿命的途径。     

New results in 2D optimal control theory

The infinite horizon optimal control problem is solved for 2D systems described by the Fornasini-Marchesini model. An ₂-approach permits us to reduce the optimal control problem to a norm minimization one in Hilbert spaces. Both necessary and sufficient conditions for solvability and the structure of the solution are established. Moreover, a comparison with known results is presented, and the singularities of the 2D Riccati equation are examined in order to characterize suboptimal control laws that apply whenever the solvability conditions are not satisfied.     

全业务运营下视频业务综合服务模型的研究

视频业务是未来支撑电信业务发展的"杀手级"业务,目前在电信领域已经陆续推出了多种视频业务平台为多种终端提供视频业务.本文以电信全业务运营为前提,剖析目前各分散的视频系统架构存在的不足,提出了视频业务综合服务模型.     

“疏堵结合”——P2P内容缓存方案

目前P2P技术已经使互联网发生了质的改变。如何合理的利用和管理P2P技术,已经摆了网路运营商面前。本文详细描述了基于"疏堵结合"思想的P2P内容缓存方案。该方案利用智能缓存技术,使P2P流量本地化,解决P2P应用的管理问题。     

An efficient in‐network caching decision algorithm for Internet of things

Recently, content‐centric networking (CCN) has become one of the important technologies for enabling the future networks. Along with its recognized potentialities as a content retrieval and dissemination solution, CCN has been also recently considered as a promising architecture for the Internet of things (IoT), because of 2 main features such as named‐based routing and in‐network caching. However, IoT is characterized by challenging features: small storage capacity of resource‐constrained devices due to cost and limitation of energy and especially transient data that impose stringent requirements on the information freshness. As a consequence, the intrinsic caching mechanisms existing in CCN approach do not well suit IoT domains; hence, providing a specific caching policy at intermediate nodes is a very challenging task. This paper proposes an effective multiattribute in‐network caching decision algorithm that performs a caching strategy in CCN‐IoT network by considering a set of crucial attributes including the content store size, hop count, particularly key temporal properties like data freshness, and the node energy level. Simulation results proved that our proposed approach outperforms 2 cache management schemes (probabilistic least recently used and AlwaysCache–first in first out in terms of improving total hit rate, reducing data retrieval delay, and enhancing content reusability in IoT environment).