Ultra-Wideband Electrostrictive Mechanical Antenna

Mechanical antennas based on piezoelectric materials can effectively reduce the size of long wave antennas down to 1/1000 of the wavelength (from km scale to mm level). However, the narrow bandwidth and weak field intensity seriously restrict its practical applications in transmission distance and channel capacity. Here, a mechanical antenna-based electrostrictive effect of relaxor ferroelectric ceramic (PMN-PT) is proposed to improve radiation capacity and achieve ultra-wideband characteristics (10 kHz–1 MHz). Due to the ultra-high dielectric constant at working temperature and the relationship between the strain and applied field intensity, the proposed antenna gets rid of the dependence on the poled materials and exhibits excellent communication properties beyond traditional mechanical antennas, which are experimentally demonstrated by a practical wireless communication system. Only using a single proposed mechanical antenna with 8 mm diameter and 3 mm thickness, the effective communication with a transmission distance of 200 m can be realized. This design offers a promising way of constructing mechanical antennas for long-wave communication.     

浅谈网络信息背景下的银行人力资源管理

当前已经逐步成为信息化、网络化,各个银行之间的竞争主要体现在其核心能力的竞争。人力资源在银行竞争中具有重要的地位和作用,在银行竞争优势中也是一种难以模仿的特定资源,是保持银行竞争优势的源泉,更是决定银行在信息化社会中竞争成败与否的关键因素。本文以网络信息时代下人力资源管理理论为基础分析我国现阶段银行人力资源管理的特点和所存在的一些问题,并针对这些问题提出对策建议,以提高人力资源管理效率,推进我国银行的发展。     

Enhanced Physiochemical and Mechanical Performance of Chitosan‐Grafted Graphene Oxide for Superior Osteoinductivity

The regeneration of artificial bone substitutes is a potential strategy for repairing bone defects. However, the development of substitutes with appropriate osteoinductivity and physiochemical properties, such as water uptake and retention, mechanical properties, and biodegradation, remains challenging. Therefore, there is a motivation to develop new synthetic grafts that possess good biocompatibility, physiochemical properties, and osteoinductivity. Here, we fabricate a biocompatible scaffold through the covalent crosslinking of graphene oxide (GO) and carboxymethyl chitosan (CMC). The resulting GO‐CMC scaffold shows significant high water retention (44% water loss) compared with unmodified CMC scaffolds (120% water loss) due to a steric hindrance effect. The modulus and hardness of the GO‐CMC scaffold are 2.75‐ and 3.51‐fold higher, respectively, than those of the CMC scaffold. Furthermore, the osteoinductivity of the GO‐CMC scaffold is enhanced due to the π–π stacking interactions of the GO sheets, which result in striking upregulation of osteogenesis‐related genes, including osteopontin, bone sialoprotein, osterix, osteocalcin, and alkaline phosphatase. Finally, the GO‐CMC scaffold exhibits excellent reparative effects in repairing rat calvarial defects via the synergistic effects of GO and bone morphogenetic protein‐2. This study provides new insights for developing bone substitutes for tissue engineering and regenerative medicine.     

基于EDGE系统信道估计实现方案的研究

研究了基于ＥＤＧＥ系统接收机中信道估计的实现方案，并对算法的各项性能做出评估。首先论述了算法的采用及其理论依据。接着，说明了信道预估计的原理及方法。最后，针对ＭＡＴ－ＬＡＢ及 ＤＳＰ上的仿真结果，比较了各项系数对于系统性能改善所具有的影响和作用，对系统特性作了较为详细的分析总结。     

一种基于频域的视频压缩算法及其实现

提出了一种基于频域的视频编码的方案并描述其如何实现，该算法利用DCT变换和运动图像前后帧在频域的三种状态，对图像快速高效编解码，运算量低，可在PC机上用软件实时实现。     

气液两相流容积含气率的精确测量

设计了一个一种新型多圈环形管用于气液两相流参数的测量,对环形管上升段水平方向内外侧气液两相流差压波动信号进行了分析;采用无因次分析方法获得与差压波动信号均方根相关的特征量,建立了此特征量与容积含气率的关系模型,并在此基础上进行了实验.实验结果表明与在气体密度已知的情况下,可以得到差压波动信号均方根有关的特征量和容积含气率存在一定的关系,在考虑到气体密度的影响之后,引入气体密度对关系模型进行修正,建立了差压波动信号均方根和容积含气率量纲1的线性关系模型.在容积含气率小于0.65时,气液两相流的容积含气率测量误差小于5为4.46%,为气液两相流的容积含气率测量提供了一种方法.     

Cr掺杂InAs自组织量子点的分子束外延生长及磁性质

利用低温分子束外延技术制备了Cr掺杂的InAs铁磁性自组织量子点.高分辨电子显微镜分析表明InAs:Cr量子点保持了较好的闪锌矿结构.超导量子干涉仪磁性测量表明InAs:Cr自组织量子点的铁磁转变温度超过400K.     

基于物联网的联合训练导控系统框架

为了更好地开展联合训练,利用物联网技术搭建联合训练的导控系统。在分析功能需求的基础上,探讨了导控系统的总体结构,并将该系统的各功能模块融入到物联网的感知层、网络层和应用层3层体系结构中,使整个导控系统被物联网覆盖,成为物联网的一个特定实体。通过对系统分层讨论,给出了基于物联网技术进行系统设计的总体思路。研究分析了系统的总体框架和技术架构,可为日后系统开发奠定理论基础。     

SOA全台网络化节目制播体系环境下跨系统工作流程设计和服务关系(下)

(上接第6期53页) 2跨系统工作流程设计和服务关系 在进行网络化节目制播体系跨系统工作流程的设计时,需要根据业务域划分情况.从数据交换、服务关系和数据流向等多个角度对电视业务进行分析,并根据分析结果完成流程的抽象、枚举、定义和细化过程.     

On a MIMO-based open wireless architecture: space-time complementary coding [Accepted from Open Call]

This article proposes a MIMO-based open wireless architecture for next-generation wireless systems. The use of space-time complementary coding in the proposed OWA scheme contributes to a great improvement in system performance due to the joint spatial diversity and multiplexing advantages achieved by the STCC-MIMO scheme. The proposed STCC-MIMO-based OWA scheme offers an unified platform that integrates various attractive features, such as link adaptation, spatial diversity and multiplexing trade-off, and accurate channel estimation. The application of innovative pair-wise complementary codes and offset stacking spread spectrum in the STCC-MIMO scheme helps to boost the overall spectral efficiency due to its near interference-free operation. MIMO systems play an extremely important role in 4G wireless, and therefore it is desirable that the OWA support different MIMO configurations. This article shows that the proposed STCC-MIMO scheme offers great flexibility to implement a MIMO system suitable for different diversity and multiplexing requirements