两种WCDMA无线利用率浅析及高效小区判定方法

以网络极限承载能力为突破口,对两种无线资源利用率算法进行浅析,研究在网络极限能力下的实际运行效率,并将两种算法联合分析,通过两种建模,给出判定高效小区的初步方法。     

Direct 3D Printing of Ultralight Graphene Oxide Aerogel Microlattices

Graphene aerogel microlattices (GAMs) hold great prospects for many multifunctional applications due to their low density, high porosity, designed lattice structures, good elasticity, and tunable electrical conductivity. Previous 3D printing approaches to fabricate GAMs require either high content of additives or complex processes, limiting their wide applications. Here, a facile ion‐induced gelation method is demonstrated to directly print GAMs from graphene oxide (GO) based ink. With trace addition of Ca²⁺ ions as gelators, aqueous GO sol converts to printable gel ink. Self‐standing 3D structures with programmable microlattices are directly printed just in air at room temperature. The rich hierarchical pores and high electrical conductivity of GAMs bring admirable capacitive performance for supercapacitors. The gravimetric capacitance (C_s) of GAMs is 213 F g^?1 at 0.5 A g^?1 and 183 F g^?1 at 100 A g^?1, and retains over 90% after 50 000 cycles. The facile, direct 3D printing of neat graphene oxide can promote wide applications of GAMs from energy storage to tissue engineering scaffolds.     

Syndrome trellis codes based on minimal span generator matrix

To improve the embedding efficiency of steganography, syndrome coding based on the coding theory has attracted many researchers’ attentions. In this paper, we make use of the relationship between syndrome coding for minimizing additive distortion and maximum likelihood decoding for linear codes to analyze the main parameters of convolutional codes which influence the embedding efficiency. And, the new syndrome trellis codes based on minimal span generator matrix is proposed. It can be considered an alternative construction of the state-of-the-art syndrome trellis codes (STCs) proposed by Filler and Fridrich recently. Experimental results show that the proposed scheme owns the same embedding performance to STCs and achieve the reduced time complexity and storage requirement meanwhile.     

Joint admission control algorithm based on load transfer in heterogeneous networks

A load-transfer-based joint admission control (LJAC) algorithm in heterogeneous networks was proposed.The access requirements of users were admitted based on load balancing,the dynamic load transfer of traffics in the overlapping coverage areas of heterogeneous networks were introduced,and the influence of such factors as the layout of heterogeneous networks and the vertical handoff was considered in the algorithm.The integrated system of heterogeneous networks was modeled as a multidimensional Markov chain,the steady-state probabilities were obtained and the quality of service (QoS) performance metrics were derived.Based on the Poisson point process theory,the upper bound of capacity of the heterogeneous networks satisfying QoS limitations was obtained.The admission control parameters of the integrated system of heterogeneous networks were optimized in order to maximize the resource utilization rate as well as guaranteeing the QoS of users.The simulation results demonstrate lower traffic blocking probability,lower failure probability of vertical handoff requirements,and larger system capacity gain can be achieved by using the proposed LJAC algorithm.     

PowerPoint变体动画效果原理解析及应用研究

变体动画的出现弥补了PowerPoint软件一直以来在形状补间动画实现手段上的不足.本文对变体动画的功能做了详细的介绍.并针对变体动画中最重要的轮廓变形效果在变形过程中随机性强、不可控的问题,解析了动画实现的原理,提出了制作思路,使此类效果的变形过程变得可控,并更加精确,这在以往的文献中未曾见到.文中所列举实例,也体现了变体动画的神奇效果.     

Use of Mesoscopic Host Matrix to Induce Ferrimagnetism in Antiferromagnetic Spinel Oxide

Despite the advances in the methods for fabricating nanoscale materials, critical issues remain, such as the difficulties encountered in anchoring, and the deterioration in their stability after integration with other components. These issues need to be addressed to further increase the scope of their applicability. In this study, using epitaxial mesoscopic host matrices, materials are spatially confined at the nanoscale, and are supported, anchored, and stabilized. They also exhibit properties distinct from the bulk counterparts proving their high quality nanoscale nature. ZnFe₂O₄ and SrTiO₃ are used as the model confined material and host matrix, respectively. The ZnFe₂O₄ phases are spatially confined by the SrTiO₃ mesoscopic matrix and have strongly enhanced ferrimagnetic properties as compared to bulk and plain thin films of ZnFe₂O₄, with a Curie temperature of ≈500 K. The results of a series of control experiments and characterization measurements indicate that cationic inversion, which originates from the high interface‐to‐volume ratio of the ZnFe₂O₄ phase in the ZnFe₂O₄–SrTiO₃ nanocomposite film, is responsible for the magnetization enhancement. An exchange bias is observed, owing to the coexistence of ferrimagnetic and antiferromagnetic regions in the confined ZnFe₂O₄ phase. The magnetic properties are dependent on the ZnFe₂O₄ crystallite size, which can be controlled by the growth conditions.     

Effects of Multiple Stacking Faults on the Electronic and Optical Properties of Armchair MoS$$_{}$$ Nanoribbons: First-Principles Calculations

The electronic and optical properties of armchair MoS\(_{2}\) nanoribbons with multiple stacking faults are investigated using first-principles calculations. It’s interesting that the band gaps approach zero for armchair MoS\(_{2}\) nanoribbons with two and four stacking faults. The gaps of armchair MoS\(_{2}\) nanoribbons with one stacking fault and three stacking faults are converged to 0.46 eV and 0.36 eV, respectively, which is smaller than perfect MoS\(_{2}\) nanoribbons. The partial charge density of armchair MoS\(_{2}\) nanoribbons with two stacking faults shows that the defect levels are originated from stacking faults. The frequency-dependent optical response (dielectric function, absorption, reflectance and electron energy loss spectra) is also presented. The optical results of monolayer MoS\(_{2}\) are in agreement with previous study. The peaks in the imaginary part of perfect armchair MoS\(_{2}\) nanoribbons are about 2.8 eV, 4.0 eV and 5.4 eV and the peaks of the imaginary part of armchair MoS\(_{2}\) nanoribbons with stacking faults are mainly 2.8 eV and 5.4 eV. They are independent of ribbon width. The peaks in electron energy loss spectra move toward larger wavelengths (redshift) due to the introduction of stacking faults.     

Molecular-level Designed Polymer Electrolyte for High-Voltage Lithium–Metal Solid-State Batteries

In solid polymer electrolytes (SPEs) based Li–metal batteries, the inhomogeneous migration of dual-ion in the cell results in large concentration polarization and reduces interfacial stability during cycling. A special molecular-level designed polymer electrolyte (MDPE) is proposed by embedding a special functional group (4-vinylbenzotrifluoride) in the polycarbonate base. In MDPE, the polymer matrix obtained by copolymerization of vinylidene carbonate and 4-vinylbenzotrifluoride is coupled with the anion of lithium-salt by hydrogen bonding and the “σ-hole” effect of the C F bond. This intermolecular interaction limits the migration of the anion and increases the ionic transfer number of MDPE (t_Li⁺ = 0.76). The mechanisms of the enhanced t_Li⁺ of MDPE are profoundly understood by conducting first-principles density functional theory calculation. Furthermore, MDPE has an electrochemical stability window (4.9 V) and excellent electrochemical stability with Li–metal due to the CO group and trifluoromethylbenzene (ph-CF₃) of the polymer matrix. Benefited from these merits, LiNi_0.8Co_0.1Mn_0.1O₂-based solid-state cells with the MDPE as both the electrolyte host and electrode binder exhibit good rate and cycling performance. This study demonstrates that polymer electrolytes designed at the molecular level can provide a broader platform for the high-performance design needs of lithium batteries.     

业务光网络中光服务等级协定的研究

从业务光网络的角度对比服务等级协定(SLA)定义了光服务等级协定(O-SLA)的框架结构,在此基础上重点分析了O-SLA协商机制并提出一种动态协商的概念,对动态协商机制的实现流程进行了分析研究.随后总结了O-SLA得以有效实施的关键技术,并提出一种支持区分服务的O-SLA实施流程,此流程对于向端用户提供可定制化的光层业务提供了一种新思路.     

基于SEP4020处理器的磁条卡读卡器Linux驱动设计

设计了智能金融终端中磁条卡读卡器在SEP4020嵌入式微处理器上的Linux驱动程序,并详细叙述了该驱动的设计思路。磁条卡读卡器运用M3—2200F／2F解码集成芯片进行磁信号的硬件转换,用SEP4020作为主处理器,实现了磁条卡读卡器的刷卡、数据采集、处理、校验等功能。