和速率约束下衰落高斯MIMO广播信道的和功率优化

 本文研究了在系统和速率一定的条件下有着高斯噪声的衰落MIMO广播信道和功率最小化问题.该问题通常存在于无线通信系统动态资源分配中,是和功率约束下衰落MIMO下行链路和速率最大化的互补问题.首先利用MIMO MAC和MIMO BC的对偶性,将问题描述和转化为凸最优化问题,在此基础上,利用子梯度法和二分法,设计了相应的快速迭代的多用户注水算法,用于计算基站的发射功率.理论分析和数值仿真结果表明,该算法全局有效地收敛于最小的和功率.     

三元层状化合物Al_3BC_3研究现状

综述了Al3BC3这种具有层状陶瓷的制备方法、结构、性能,以及国内外的研究现状。     

广州中心城区冬季大气气溶胶消光特性观测研究

2013年12月利用广州市大气超级站气溶胶吸收系数、散射系数、污染物及气象观测数据,分析了广州冬季大气消光组成变化及其影响因子。观测期间,黑碳浓度均值为6．98±3．71μg／m^3,气溶胶吸收系数均值为60．04±30．72Mm^-1,气溶胶散射系数均值为363．51±182．18Mm^-1,单次散射反照率均值为0．85±0．04。在总消光系数中气溶胶吸收消光占13％,气溶胶散射消光占81％。气溶胶吸收系数与散射系数日变化均呈双峰结构,这与人类活动和气象条件的改变有关。通过最大频数拟合得到广州冬季气溶胶吸收系数和散射系数本底值分别为32．93Mm^-1和281．82Mm^-1。气溶胶散射系数和吸收系数与PM2.5质量浓度呈线性正相关,与大气能见度呈指数负相关。通过测量气溶胶消光和气体消光分量加和获得的消光系数与能见度仪消光系数变化趋势基本一致,降雨及较高相对湿度对能见度仪消光系数影响较大。     

基于细菌趋药性算法的盲图像分离方法

提出了一种新的基于细菌趋药性(BC)算法的盲图像分离方法,利用图像信号的规范四阶累积量作为目标函数,使用BC算法对目标函数进行优化以实现图像的盲分离。每分离出一幅图像后,从混合图像中消除该幅图像成分后再进行下一次分离,从而最终实现所有源图像的逐次分离。仿真结果表明,本文算法能够有效实现对多幅混合自然图像的盲分离,且具有较好的分离效果。     

Biomimetic plant foods: Structural design and functionality

BackgroundThe rising number of people living with chronic conditions, such as diabetes and cardiovascular disease, along with the widespread demand for healthier foods have posed significant challenges to the food industry. Plant-based foods, beyond simple nutrition, can provide health-benefiting functionalities within the complex environment of the human gastrointestinal (GI) tract. Biomimetics is defined as taking inspirations from nature to solve problems. Biomimetic plant foods (BPFs) can offer solutions for the future with the design of nature-inspired food structures for improved health and well-being.Scope and approachThis review provides an insight into the assembly of plant food structures and their disassembly in the human GI tract. Their role in controlling the digestive fate of nutrients is elucidated. Recent developments and future perspectives on designing BPFs are also presented and discussed.Key findings and conclusionsPlant foods in nature possess hierarchically self-assembled structures. During processing and GI digestion, these structures are disassembled to enable liberation and assimilation of nutrients and bioactive molecules contained within the food matrix. The assembly and disassembly are linked to a hierarchy of structure in plants within which different levels (molecule, polymer, cell wall, cell, tissue, organ) and their interactions can modulate nutrient bioaccessibility and digestion. Inspired by nature, BPFs can be engineered to deliver in-body functionality. The emerging trend of biomimetics will potentially pave the way for the future of food.     

浅谈广电客户服务中心的职责

广电客户服务中心是广电信息网络公司经营服务活动中的信息中心,是公司各个职能部门间沟通的桥梁和纽带,是企业提升经营服务水平的重要阵地,是公司对外的重要窗口,承担着为用户提供满意服务的重要责任。     

Experimental and numerical life evaluation of TBCs with different BC and diffusion coating under cyclic thermal loading

This paper experimentally and numerically investigates the thermally grown oxide (TGO), lifetime, and stress values in thermal barrier coatings with different bond coat (BC), without top coat (TC), and diffusion coating under cyclic thermal loading. Scanning electron microscope (SEM) analysis shows that the atmospheric plasma spraying (APS) and high-velocity oxygen fuel (HVOF) fabricated sample has the highest and lowest TGO thickness and growth rate, respectively. The new coating with two BCs has a maximum lifetime of 102 cycles. After that, the lifetime of the coatings with HVOF-BC, diffusion coating, and APS-BC reach 84, 56, and 44 cycles, respectively. The diffusion coating does not have much effect on the TGO thickness; however, it delays the Al interdiffusion to the substrate. In the sample without the TC layer, oxygen contact with the BC layer has increased, leading to a rise in the BC oxidation rate. The numerical analysis of the stress values based on SEM images shows that the more intense TGO layer growth in APS coating caused an increase in TC layer stress values. Furthermore, the results show that the new coating with two-layer BC has the lowest stress values. The TC absence causes the loss of compressive stresses caused by TC on TGO and increases the tensile stress values in this layer.     

高效安全的超微细抗菌粉体BC107

介绍了一种新型的载银超微细抗菌粉体BC10 7的性能和应用 ,该抗菌剂具有高效安全、稳定等特点 ,应用领域十分广泛。     

A Unified Scaling-Up Technique for Pneumatic Conveying Systems

A major challenge facing the designers of pneumatic transportation systems is how to scale up reliably based on the results from pilot-scale test facilities. Further, even if dense phase flow condition prevails at the start of the conveying system, it may be a dilute phase flow condition at the end of the pipeline. Hence, any scaling-up technique should be able to address the dynamic change of flow condition along the pipeline. The scaling-up technique presented here using the pressure drop prediction models based on modified Darcy-Weisbach equation successfully addresses these dynamic changes. It has been shown that the pressure drop coefficient 'K,' as defined by the models, is independent of the pipe diameter. Further, in the case of vertical conveying, 'K' has been shown to be independent of particle size distribution for a given material. The predicted pressure values were found to be in reasonably good agreement with the experimental results varying from 3.5% to 19.9%.