国有大旅行社市场渠道策略变革探讨

通过对近年来国有大旅行社渠道建设的现状分析,总结出国有大旅行社渠道变革的三大趋势,并分析这些变革趋势的动因。     

宏小区高天线环境下波达角度和时间的预测

为提高对空时到达分布预测的准确度,介绍了一种适用于小区高天线环境下波达角度和时间预测、的改进的圆散射模型。分别给出了波达角度和时间分布概率密度函数的表达式。仿真结果与实测数据的比较表明,较传统的基于散射体的单反宏小区模型而言,改进的圆模型能更合理地对传播建模,且在波达角度和时间的预测方面具有更高的准确度。     

垂直水声通信中的伪随机序列精确定时算法*

针对垂直水声通信中时变多普勒引起的定时偏差问题,研究一种基于伪随机序列的迭代定时估计及补偿算法。该方法利用伪随机序列作为同步信号,分三步估计时变多普勒：采用低复杂度的模糊函数法粗补偿接收信号内的平均多普勒;通过迭代插值法实现残留时变多普勒的精确估计及补偿;利用基于信道相关函数的相位信息,纠正均衡后信号的偏转相位。为实现高阶海试数据的有效解调,采用基于伪随机序列均方误差的多通道加权合并方式,获得空间分集增益。仿真及海试数据处理结果证明所提方法具有良好的时变多普勒估计及补偿性能,同时对30个通道内的1024QAM数据进行合并处理,在500 m的通信距离下,误码率为0.04,信道容量达到7.6 bits/symbol。与传统数据帧结构相比,无需使用线性调频信号,可以提高有效数据传输率。     

价格与质量双重竞争下电商平台渠道模式决策研究

近年来传统电商正加速从经销商转变为连接消费者与供应商的在线市场中间商,电商平台与供应商形成三种渠道结构：经销商模式、混合模式和在线市场模式。本文通过构建Stackelberg博弈模型讨论产品质量与价格双重竞争情境下电商平台与供应商销售合作模式最新选择问题。研究表明,当价格竞争强度适中而佣金比例较大时,混合模式是电商平台最优选择,此时产品质量差异最大;当价格竞争强度较小而佣金比例较大时,在线市场模式则是最优选择;在其他条件下,经销商模式是其最优选择。本文结论对电商平台与供应商合作模式选择、产品质量与定价决策具有参考价值。     

Sarcorucinine-D Inhibits Cholinesterases and Calcium Channels: Molecular Dynamics Simulation and In Vitro Mechanistic Investigations

Acetylcholinesterase (AChE) inhibitors and calcium channel blockers are considered effective therapies for Alzheimer’s disease. AChE plays an essential role in the nervous system by catalyzing the hydrolysis of the neurotransmitter acetylcholine. In this study, the inhibition of the enzyme AChE by Sarcorucinine-D, a pregnane type steroidal alkaloid, was investigated with experimental enzyme kinetics and molecular dynamics (MD) simulation techniques. Kinetics studies showed that Sarcorucinine-D inhibits two cholinesterases—AChE and butyrylcholinesterase (BChE)—noncompetitively, with K_i values of 103.3 and 4.66 µM, respectively. In silico ligand-protein docking and MD simulation studies conducted on AChE predicted that Sarcorucinine-D interacted via hydrophobic interactions and hydrogen bonds with the residues of the active-site gorge of AChE. Sarcorucinine-D was able to relax contractility concentration-dependently in the intestinal smooth muscles of jejunum obtained from rabbits. Not only was the spontaneous spasmogenicity inhibited, but it also suppressed K⁺-mediated spasmogenicity, indicating an effect via the inhibition of voltage-dependent Ca²⁺ channels. Sarcorucinine-D could be considered a potential lead molecule based on its properties as a noncompetitive AChE inhibitor and a Ca²⁺ channel blocker.     

Solvothermal Synthesis and Crystal Structure of a Layered Thioantimonate(Ⅲ) [C4H9NH3]2Sb4S7

An inorganic-organic hybrid thioantimonate(Ⅲ) [CH3(CH2)3NH3]2Sb4S7 1 with layered structure was synthesized by solvothermal method.1 crystallizes in the triclinic system, space group P with a = 7.0124(11), b = 11.919(2), c = 14.879(3) (A), α = 108.791(3), β = 102.441(3), γ = 92.846(2)o, V = 1140.1(3) (A)3, Mr = 859.71, Z = 2, Dc = 2.504 g/cm3, μ= 5.324 mm-1, F(000) = 804, S = 1.013, the final R = 0.0297 and wR = 0.0618 for 3534 observed reflections with I＞2σ(I). 1 consists of [C4H9NH3] cations and two-dimensional [Sb4S7]n2n-anion which is composed of three SbS3 trigonal pyramids and one SbS4 unit joined by sharing common corners. The anionic layers are stacked perpendicularly to the c axis of the unit cell forming two-dimensional channels between the layers. The [C4H9NH3] cations interdigitate in a bilayer and reside in the 2D channels leading to a sandwich-like arrangement of the anion and cations.     

A Zn(Ⅱ) 5-Aminoisophthalate Coordination Polymer

The title compound, [Zn(AIP)(4,4-bipy)0.5(H2O)]n·0.75nH2O 1, was synthesized via the hydrothermal reaction of Zn(OAc)2 with 5-aminoisophthalic acid (H2AIP) and characterized by elemental analysis and infrared spectra. The complex crystallizes in monoclinic system, space group P21/c with a = 12.672(1), b = 7.6557(4), c = 16.181(1) (A),β = 109.187(2)o, V = 1482.6(2) (A)3, Z = 1, C52H52N8O23Zn4, Mr = 1418.58, Dc = 1.589 g/cm3, F(000) = 724 and μ(MoKα) = 1.685mm-1. The final R = 0.0702 and wR = 0.1524 for 1847 observed reflections with Ⅰ ＞ 2σ(I), and R = 0.0873 and wR = 0.1664 for all data. X-ray diffraction studies reveal that the title compound has an interesting 2D microporous architecture with guest water molecules inside the channel.     

16QAM-OFDM系统的迭代信道估计

传统的OFDM信道估计器和译码器分开进行,信道估计的可靠性不高.针对16QAM高效调制的OFDM系统,提出了一种基于Turbo译码的迭代信道估计方案.在迭代过程中利用译码器产生的可靠信息来改善信道估计的精度;同时推导了16QAM软去映射、校验比特译码和符号重构算法的数学过程.为了防止由于译码器判决不准造成的误差传播,提出了一种基于门限控制的迭代估计算法.仿真结果表明,该算法可有效改善系统的整体性能.     

川西新场—什邡地区三维连片河道砂岩处理技术

川西中浅层河道砂体厚度薄、宽度窄,地震识别难度大,保持地震反射振幅与波形的相对变化关系是地震技术识别砂体展布的前提。新场—什邡地区10块三维区块资料由于采集年代跨度大、采集仪器不同、观测系统不一样,导致单块数据之间存在系统时差以及振幅、频率和波形等不一致问题。在分析原始数据基础上,明确了三维连片河道砂岩目标处理面临的问题及难点,建立了一套解决该问题的方案与思路。资料处理以提高中浅层成像效果和突出河道砂岩地震响应特征为目的,主要对时差校正、去噪、静校正、振幅恢复与补偿、反褶积、地表一致性处理、剩余静校正、数据规则化、速度分析、偏移成像和道集优化等技术进行了研究、试验和分析,并完成实际数据处理。处理成果具有高信噪比、高分辨率和较高保真度的特点,区块之间波组连续稳定一致性好,可为后续构造解释、砂体刻画、储层预测和含气性识别等研究提供高质量的基础资料。     

深水浊积水道型储层砂体连通性定量表征探索

在深水浊积水道型油田开发实践中发现,因砂地比较高、储层品质较好,作为开发单元的复合水道砂体表现为整体泛连通,但是在不同位置连通情况存在差异。为准确、精细地刻画水道砂体内部不同位置的连通程度,提升注采受效和开发效果,采用构型表征的方法,将储层砂体细分为构型单元和构型边界,结合西秦岭地区重力流沉积露头展现出的精细特征分别定量刻画其对连通性的影响,并通过地质模型应用于开发生产。研究发现,对高砂地比的浊积水道型储层而言,水道构型单元和水道构型界面同时影响连通性,且一般构型界面占主导,可以采用构型单元-界面二元表征的方法将砂体间特征对连通性的影响加以刻画;通过“连通系数”定量刻画和衡量砂体间的连通情况,并通过“等效替代”的方法计算连通系数。