基于自组织理论的电子商务市场网络演化机制探讨

经济全球化视域下,商业模式变幻莫测,我国市场经济模式为了迎合市场的发展需求,也在不断改变。近年来,传统实体销售模式已经无法满足现代人的购物需求,电子商务市场的网络化发展成为了主流,且形成了多样化的电子商务模式。本文基于自组织理论,通过阐述电子商务市场网络演化的理论基础,对我国电子商务市场网络框架的复杂性进行具体分析。通过对商业系统演化机制的研究,分析出我国电子商务网络演化机制过程中出现的问题,并针对问题提出解决对策,促进我国电子商务网络化机制的发展,为我国经济新常态化发展助力。

一种基于哈密顿矩阵的电子波函数演化算法

电子的运动与演化是贯穿许多物理化学过程的主线,而对这一过程的精确模拟和分析是发展有效的电子调控方法和应用的关键.传统方法,如TDHF(time-dependent Hartree-Fock)、TDDFT(time-dependent density functional theory)等,在模拟小尺度体系内的电子演化时表现优异,然而,在模拟大尺度体系时计算复杂度偏高,成本较大.在一些大尺度体系内,原子核位置相对固定,并且微扰对整体相互作用的哈密顿量影响较小.为此提出了一种简单有效的基于哈密顿矩阵的电子波函数演化方法,这一方法能处理远远大于TDDFT计算尺度的大体系.通过将该方法应用于四个不同的体系进行测试分析,验证了这一方法在处理大体系时的可行性,并为相关的电子调控应用提供了新的思路.

钨杂质辐射对托卡马克等离子体大破裂快速热猝灭阶段热能损失过程的影响

基于PLT,EAST,WEST,ASDEX-Upgrade,JET等托卡马克装置开展的研究表明重杂质易产生聚芯现象,这会导致等离子体约束性能降低甚至引发等离子体大破裂事件.大破裂期间等离子体热能损失主要发生在快速热猝灭(thermal quench,TQ)阶段,但目前对于这一阶段的时间尺度定标关系并没有较为全面的物理解释.国际热核聚变实验堆(International Thermonuclear Experimental Reactor,ITER)将采用全钨壁材料,而钨作为高Z杂质,其较强的辐射能力将会对TQ过程的热能损失产生影响.为研究钨杂质对快速TQ时间尺度的影响,本工作通过同时考虑随机磁场导致的热扩散以及钨杂质辐射引起的热损失机制,建立了托卡马克等离子体电子温度演化的一维模型,并在典型类ITER参数下对该阶段的电子温度演化进行数值计算和分析.主要结论为:1)快速TQ时间尺度的量级由热扩散水平决定,但钨杂质辐射可以定量上影响TQ时间尺度和TQ后期电子温度,钨浓度越高TQ时间尺度越短、后期电子温度越低,且数值与解析结果分析都表明该时间尺度与钨杂质浓度近似呈线性关系;2)快速TQ阶段前期,通过钨杂质辐射损失的能量远小于通过随机磁场引起热扩散损失的能量,但在TQ后期,钨杂质辐射功率量级可以接近甚至超过热扩散功率,这也是导致TQ后期电子温度随钨浓度增大而降低的原因.因此,钨杂质辐射在TQ后期对热能损失的贡献不可忽略.

离子液中溶剂化电子的结构及其演化动力学

本文综述了离子型液体介质中过剩电子的结构、存在状态及其时间演化动力学特征。基于从头算分子动力学模拟及计算结果,重点阐述了咪唑型、吡啶型、碱金属离子型熔盐氯化物离子液中与过剩电子溶剂化密切相关的溶剂化能量学、结构特征、可能的存在状态以及态-态转化稳态动力学机制,分析了此类离子型介质中电子高效传导的内在本质及离子液组成离子的重要作用。阳离子的最低未占轨道组成的导带结构是离子液中过剩电子的溶剂化态及其稳定性的决定因素,任何能影响或改变其导带结构的因素均能显著影响过剩电子溶剂化。但快速的态-态转化及电子迁移并不明显取决于其组成离子扩散动力学,而是敏感地受离子液涨落所控制。这种基于溶剂化电子的迁移模式构成了此类离子型介质甚至其他液态介质中电子转移的新途径。

考虑空间电荷自洽作用和绝缘磁场的单边multipactor模型

在考虑了波束相互作用腔中的射频场、聚焦磁场和空间电荷产生的静电场及空间电子束形成自洽相互作用的基础上,针对典型的高功率微波器件——磁绝缘线振荡器建立了单边次级电子倍增模型,统计分析了整个倍增过程中次级电子数目及器件腔壁吸收碰撞电子能量随时间的变化规律,给出了不同聚焦磁场值和电子碰撞角时次级电子的倍增情况.

Research on E-mail Communication Network Evolution Model Based on User Information Propagation

E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of Enron dataset and the distribution of node degree and strength are analyzed. Then, some rules of e-mail communication network evolution are found. Second, the model of e-mail information propagation is described, and e-mail communication network evolution model based on user information propagation is proposed. Lastly, the simulation proves the correctness of the distribution characteristic of degree and strength of the model proposed and then verifies that the model proposed is closer to the real situation of e-mail communication network through parameter comparison. This research provides the basis for other researches on social network evolution and data communication.

Diagenesis and porosity evolution of sandstone reservoirs in the East II part of Sulige gas field, Ordos Basin

It is becoming an important controlling factor of gas exploration and exploitation in the east part of Sulige gas field in the Ordos Basin where the reservoir of main gas formations is tight sandstones. Employing experimental methods of slice identification, casting slice, scan electron microscope, and X-ray diffrac- tions, we studied the characteristics of petrology and diagenesis on reservoirs in Shanl section of Shanxi formation and He8 section of Shihezi formation of the Permian system in the East II part of Sulige gas field. The results include： （1） the main sandstones in these areas are dominated by lithic sandstone and litbic silicarenite with low grade of maturity; （2） the diagenesis of sandstone in these areas mainly include compaction, cementation, corrosion and alteration. Conclusions are as follows： （1） the diagenetic stage reached period B of the middle diagenetic stage; （2） the early diagenetic compaction is one of the main factors to decreasing porosity; （3） the secondary pores formed by corrosion in acidity medium con- ditions in period A of the middle diagenetic stage can distinctly ameliorate the poor reservoir capability of sandstone and, （4） cementation in period B of the middle diagenetic stage is the most important factor leading; to poor physical property of sandstone reservoirs.

Performances of lithium manganese oxide prepared by hydrothermal process

A simple hydrothermal process followed by heat treatment was applied to the preparation of spinel Li1.05Mn1.95O4. In this process, electrolytic manganese dioxide(EMD) and LiOH·H2O were used as starting materials. The physiochemical properties of the synthesized samples were investigated by thermogravimetry-differential scanning calorimetry(TG-DSC), X-ray diffractometry(XRD), and scanning electronic microscopy(SEM). The results show that the hydrothermally synthesized precursor is an essential amorphous. The precursor can be easily transferred to spinel powders with a homogeneous structure and a regularly-shaped morphology by heat treatment. Li1.05Mn1.95O4 powder obtained by heat treating the precursor at 430 °C for 12 h and then calcining at 800 °C for 12 h shows an excellent cycling performance with an initial charge capacity of 118.2 mA·h·g-1 obtained at 0.5C rate and 93.8% of its original value retained after 100 cycles.

基于MILO结构的一种单边multipactor模型分析

根据高功率微波源相互作用腔的物理结构特性,以磁绝缘传输线振荡器(MILO)为例,建立了一种单边二次电子倍增效应(mulitpactor)模型.采用概率统计和蒙特卡罗(MC)模拟方法,计算了敏感曲线和二次电子的时间演化规律,分析了射频场参数对二次电子倍增效应的影响,并提出了减小和抑制二次电子倍增效应的具体措施.

Mineral photoelectrons and their implications for the origin and early evolution of life on Earth

Energy is the key issue of all life activities.The energy source and energy yielding pathway are the key scientific issues of the origin and early evolution of life on Earth.Current researches indicate that the utilization of solar energy in large scale by life was an important breaking point of the early evolution of life on Earth and afterwards life gradually developed and flourished.However,in the widespread biochemical electron transfer of life activities,it is still not clear whether the electron source is sun or how electrons originated from sun.For billions of years,the ubiquitous semiconducting minerals in epigeosphere absorb solar energy,forming photoelectrons and photoholes.In reductive and weak acidic environment of early Earth,when photoholes were easily scavenged by reducing matters,photoelectrons were separated.Photoelectrons could effectively reduce carbon dioxide to organic matters,possibly providing organic matter foundation for the origin of life.Photoelectrons participated in photoelectron transfer chains driven by potential difference and transfer into primitive cells to maintain metabolisms.Semiconducting minerals,by absorbing ultraviolet,also protected primitive cells from being damaged by ultraviolet in the origin of life.Due to the continuous photoelectrons generation in semiconducting minerals and utilization by primitive cells,photoelectrons from semiconducting minerals’photocatalysis played multiple roles in the origin of life on early Earth,such as organic synthesis,cell protection,and energy supply.This mechanism still plays important roles in modern Earth surface systems.

An explanation of the elliptic flow difference between proton and anti-proton from the UrQMD model with hadron potentials

The time evolution of both proton and anti-proton v2 flows from Au＋Au collisions at √SNN=7.7 GeV are examined by using both pure cascade and mean-field potential versions of the UrQMD model. Due to a stronger repulsion at the early stage introduced by the repulsive potentials and hence much less annihilation probabilities, anti-protons are frozen out earlier with smaller v2 values. Therefore, the experimental data of anti-proton v2 as well as the flow difference between proton and anti-proton can be reasonably described with the potential version of UrQMD.

Evolution of clustered magnetic nulls in a turbulent-like reconnection region in the magnetotail

t Magnetic null points and flux ropes play important roles in the three-dimensional process of magnetic reconnection. In this study, a cluster of null points are reconstructed in the reconnection region in the magnetotail by applying a fitting-reconstruction method to measurements from the Cluster mission. The number of recon- structed null points varies rapidly, presenting a turbulentlike evolution of the magnetic structure. The electron density and the flux of the accelerated electrons were enhanced in this turbulent-like region. During this unstable reconnection process, a B-As-B null structure was formed, showing flux rope features and resembling a secondary island in the observation.

In-situ TEM study of the dynamic behavior of the graphene-metal interface evolution under Joule heating

The dynamic behavior of the interface between few layer graphene(FLG) and tungsten metal tips under Joule heating has been studied by in-situ transmission electron microscopy(TEM) method. High-resolution and real-time observations show the tungsten tip ‘swallow' carbon atoms of the FLG and ‘spit' graphite shells at its surface. The tip was carbonized to tungsten carbide(WC, W_2 C and WC_x) after this process. A carbon diffusion mechanism has been proposed based on the diffusion of carbon atoms through the tungsten tip and separation from the surface of the tip. After Joule heating, the initial FLG-metal mechanical contact was transformed to FLG-WCx-W contact, which results in significant improvement on electrical conductivity at the interface.

Structural evolution and electronic properties of phosphorus-doped hydrogenated amorphous silicon thin films deposited by PECVD

The relationship between structure and electronic properties of phosphorus-doped hydrogenated amorphous silicon(a-Si:H) thin films was investigated.Samples with different features were prepared by plasma enhanced chemical vapor deposition(PECVD) at various substrate temperatures.Raman spectroscopy and Fourier transform infrared(FTIR) spectroscopy were used to evaluate the structural evolution,meanwhile,electronic-spin resonance(ESR) and optical measurement were applied to explore the electronic properties of P-doped a-Si:H thin films.The results revealed that the changes in materials structure affect directly the electronic properties and the doping efficiency of dopant.

Determination of the ^(25)Mg(p,γ)^(26)Al resonance strength at E_(c.m.)=58 keV via shell model calculation

The observation of 26Al is an useful tool for γ-ray astronomy and in studies of galactic chemical evolution. The most likely mechanism for 26Al nucleosynthesis is in the hydrogen burning MgAI cycle, and the 26Al production reaction 25Mg（p, γ）26Al at the important temperature range below T = 0.2 GK is still not well known. The spectroscopic factor of 58 keV resonance level in 26Al is determined with shell model calculation and then used to deduce the resonance strength of the 25Mg（p, γ）26Al reaction. The result provides a reference for the future 25Mg（p, γ）26Al direct measurement at Jinping underground laboratory.