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991.
花岗岩残积土浅层地基承载力评价方法探讨   总被引:1,自引:0,他引:1  
花岗岩残积土是一种特殊性土体, 是混粒土的一种特殊类型, 从而导致浅层地基承载力也具有特殊性。作者首先分析了现行实验评价方法的利弊关系, 以大量的野外实验和室内实验资料为依据, 确定了其它测试方法评价该类土体浅层地基承载力的可行性, 并提出了利用标准贯入试验击数确定浅层地基承载力的修改方案。并探讨了土体含水量和浅层地基承载力和这些影响因素之间的相互关系。  相似文献   
992.
Since optical network carries a lot of traffic, survivability is very important to ensure the service continuity against network failures. Recently, multicast services become more popular to meet the huge multimedia demand in network, so that multicast survivability in optical network has got more attention. However, multicast survivability may lead to more energy consumption due to more redundant backup resources allocated. Since greening network is particularly important with the energy crisis keeping growing, green multicast survivability in optical network is a challenging issue. This paper focuses on the green multicast grooming protection problem in optical network and designs two auxiliary graphs that includes a virtual topology graph and an integrated graph to address the survivable multicast grooming, routing and wavelength assignment. Based on the auxiliary graphs, this paper proposes an efficient heuristic called green multicast grooming algorithm based on spanning path dedicated protection (GMG-SPDP), in which the network reliability and the energy efficiency are jointly taken into account. Simulation results show that, compared to other algorithms, the proposed GMG-SPDP not only has lower blocking probability and higher bandwidth utilization ratio, but also saves more energy.  相似文献   
993.
A model of the average capacity of a ground-to-train optical wireless communication link in a horizontal channel is established by using the log-normal distribution model of the weak turbulence. The average capacity model include the effects of the turbulent wander and spread of bwams, pointing errors of links, turbulence inner scale and turbulence outer scale.  相似文献   
994.
改进电热法测量比热容方法中使用的物理公式,使实验电路更为精简。在以往比热容测定仪器的基础上进行改良,制作出新的比热容测定装置,并通过实验验证该装置测定物质比热容所能达到的精确度。对实验的数据处理方法进行改进,并验证其精度。  相似文献   
995.
如何简便地判断一个热力学过程的吸放热情况,对于了解此热力学过程是至关重要的.传统的方法是借助热力学第一定律,通过计算该热力学过程中的热学三量(功、热量和内能)来确定.文章通过分析简单热力学过程中的热容,得出:从绝热线上一点出发的微过程,过程曲线在绝热线下方,为放热过程;反之,为吸热过程.进一步,文章指出对于一些复杂的热力学过程,除使用传统的比较功大小的方法外,还可以利用热力学过程的末态相对等温线的位置而简单得出其吸放热情况。  相似文献   
996.
汪祖民  乔明超 《应用声学》2014,22(10):3433-3435
针对传统温室监测节点蓄电池剩余电量问题,提出一种改进的基于ZigBee无线通信技术的温室节点无线监测方案,设计一个经济实用的低功耗ZigBee无线监测节点;以CC2530为主控芯片,通过控制不同的传感器和电池智能管理芯片DS2438及其外围电路,实现温室环境参数和各节点蓄电池电压、电流以及剩余电量的精确测量并实时显示;测试结果表明,系统运行稳定,数据检测精度达到0.001。  相似文献   
997.
We study the stopping times of gossip algorithms for network coding. We analyze algebraic gossip (i.e., random linear coding) and consider three gossip algorithms for information spreading: Pull, Push, and Exchange. The stopping time of algebraic gossip is known to be linear for the complete graph, but the question of determining a tight upper bound or lower bounds for general graphs is still open. We take a major step in solving this question, and prove that algebraic gossip on any graph of size n is On) where Δ is the maximum degree of the graph. This leads to a tight bound of for bounded degree graphs and an upper bound of O(n2) for general graphs. We show that the latter bound is tight by providing an example of a graph with a stopping time of . Our proofs use a novel method that relies on Jackson's queuing theorem to analyze the stopping time of network coding; this technique is likely to become useful for future research. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 45, 185–217, 2014  相似文献   
998.
A partial phase diagram has been determined for the system based on 5‐phenylvalerate, 4‐pentyphenol, and water at 25 °C. The system showed a very rich phase behavior in which many different isotropic solutions and liquid crystals were found. Both normal and reverse self‐assembly structures of the micellar and hexagonal types were noted. In the middle of the phase diagram, a lamellar liquid crystalline phase with a large swelling capacity was observed. When the aromatic alcohol was replaced by a long‐chain alcohol the reverse hexagonal structure disappeared. The effect of temperature and salinity on the phase behavior was also studied. Raising the temperature increased the micellar regions, while the lamellar phase was slightly reduced and the reverse hexagonal phase disappeared. Addition of salt gave the lamellar phase a smaller region of existence and the large extension towards the water apex disappeared. Introduction of an acid to the system resulted in a remarkable change of the phase behavior: both the normal micellar and lamellar regions were significantly reduced, while the reverse micellar region was significantly increased.  相似文献   
999.
The sorption behaviour of three kinds of macrocyclic sorbents – amidoamine tetradodecyloxyphenylencalix[4]resorcinarene 1 and tetramethyloxyphenylencalix[4]-resorcinarene 2; composition of calix[4]resorcinarene 1+2, and novel P.1 and P.2 polymers with amidoamine calix[4]resorcinarene units towards three water-soluble azo dyes – methyl orange (MO), acid orange (AO5) and Congo red (CR) was studied. All sorbents form supramolecular complexes with the aforesaid dyes. The best sorbent for MO was shown to be polymer P.1, for the AO5 – composition 1+2 and for the CR – macrocycle 2, with high sorption capacities (373, 497 and 625 mg/g, respectively). The main factor in the binding of dyes by all studied sorbents proved to be surface electrostatic interactions. In addition to the Coulomb interactions, the most important factor for the polymers appeared to be the ‘net’ structure of the polymer with a high concentration of binding sites, providing electrostatic, hydrogen, dipole–dipole and hydrophobic interaction. Hydrophobic substituents in the sorbents exert a significant influence on the dye sorption. The increase of the sorbents' hydrophobicity leads to a lower sorption capacity for MO and CR and a higher sorption capacity for AO5. It was shown that sorption efficiency of the sorbent depends on the ‘dye–sorbent’ structure conformity.  相似文献   
1000.
The first stable phosphabismuthene (R 1 --P=Bi--R 2 ) and stibabismuthene (R 1 --Sb=Bi--R 2 ) were successfully synthesized by taking advantage of efficient steric protection groups, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt), 2,6-bis[bis(trimethylsilyl)-methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt), and 2,4,6-tri- t -butylphenyl (Mes*). Their spectroscopic properties and structural parameters were systematically compared with those of previously reported stable, homonuclear, doubly bonded systems, such as diphosphene, diarsene, distibene, and dibismuthene.  相似文献   
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