Triangular quad-port multi-polarized UWB MIMO antenna with enhanced isolation using neutralization ring

In this study, a quad-port multi-polarized ultra-wideband (UWB) multiple input multiple output (MIMO) antenna system with a new isolation technique is designed for wireless devices. The antenna structure consists of four triangular monopole elements and neutralization ring (NR) structures. The monopoles are back-to-back positioned in symmetrical and orthogonal arrangement. Therefore, they radiate towards four directions without interference, and thus the diversity performance is improved. A novel NR is formed by combining a rectangular ring and a straight line to reduce the mutual coupling due to interoperation of the elements. Each triangular monopole is fed by 50 Ohm microstrip transmission line (MTL) with a thin strip line for ensuring impedance matching. Antenna performance in terms of impedance bandwidth, current distribution, radiation pattern, peak gain and envelope correlation coefficient (ECC) is also investigated. The MIMO antenna system has 3.1–17.3 GHz impedance bandwidth, 1–5 dBi peak gain variation, less than 0.1 ECC. The results indicate that the proposed antenna has the characteristics of larger UWB bandwidth, high isolation by the NR structure, multi-polarization, uniform gain and quasi-omnidirectional pattern.     

Leveraging diverse knowledge sources through proactive behaviour: How companies can use inter‐organizational networks for business model innovation

The relevance of business model innovation (BMI) for strategic renewal and competitive advantage has been increasingly recognized by both strategy scholars and managers. In this paper, we explore how inter‐organizational networks and firms' proactiveness influence BMI. By examining Dutch design companies, we show that having a network of companies with different sizes has a positive effect on BMI. We also observe a positive effect of ties change. Finally, we show the importance of firms' proactiveness. Through the discussion of network elements and proactiveness as antecedents of BMI, we contribute to the business model and social network literature.     

Constrained differential evolution with multiobjective sorting mutation operators for constrained optimization

Differential evolution (DE) is a simple and powerful evolutionary algorithm for global optimization. DE with constraint handling techniques, named constrained differential evolution (CDE), can be used to solve constrained optimization problems (COPs). In existing CDEs, the parents are randomly selected from the current population to produce trial vectors. However, individuals with fitness and diversity information should have more chances to be selected. This study proposes a new CDE framework that uses nondominated sorting mutation operator based on fitness and diversity information, named MS-CDE. In MS-CDE, firstly, the fitness of each individual in the population is calculated according to the current population situation. Secondly, individuals in the current population are ranked according to their fitness and diversity contribution. Lastly, parents in the mutation operators are selected in proportion to their rankings based on fitness and diversity. Thus, promising individuals with better fitness and diversity are more likely to be selected as parents. The MS-CDE framework can be applied to most CDE variants. In this study, the framework is applied to two popular representative CDE variants, (μ + λ)-CDE and ECHT-DE. Experiment results on 24 benchmark functions from CEC’2006 and 18 benchmark functions from CEC’2010 show that the proposed framework is an effective approach to enhance the performance of CDE algorithms.     

克拉苏构造带盐下超深层储层的构造改造作用与油气勘探新发现

塔里木盆地克拉苏构造带油气群下白垩统巴什基奇克组埋深超过6 000 m,储层基质渗透率低,裂缝普遍发育,构造对储层的改造作用明显,但博孜9井的勘探突破反映出不同区带间构造改造作用差异较大、非均质性极强,重新认识构造对储层的改造作用对于预测超深层储层、指导油气勘探生产具有重要的意义。为此,基于钻井取心、构造平衡恢复、裂缝充填物同位素测年、区块应力数值模拟等资料,结合流体包裹体、声发射古应力、铸体薄片等实验分析方法,从定性分析到定量计算、研究了克拉苏构造带油气群超深层储层的构造改造作用及其差异性。研究结果表明:①北部天山造山带及南部古隆起控制了该构造带储层的沉积格局及差异构造变形,形成巴什基奇克组储层"西薄东厚"的分布特征;②博孜区段古应力最小,构造变形主要为正向挤压、逆冲传播,局部井区为斜向压扭;③大北区段主要为斜向压扭,古应力较小,构造变形为逆冲叠置;克深区段古应力最大,构造变形主要为正向挤压、后缘逆冲抬升、前缘滑脱收缩;④差异构造变形使同一构造带不同构造变形样式的构造减孔量呈现出较大的差别,且控制了不同区段造缝期与成岩胶结的叠加影响、中晚期裂缝网络与油气成藏期的配置关系,加剧了储层的非均质性,是区段间产能差异的基础改造因素;⑤现今构造应力的大小及方向影响裂缝有效性,南部为强挤压应力区,背斜相对高部位裂缝走向与现今应力交角较小,裂缝有效性最好;⑥构造成岩环境决定了构造裂缝充填物的类型,北部区块以淡水—半碱水介质成岩环境为主,裂缝充填物类型为方解石,有利于对储层进行酸化压裂改造。     

乡土之路--杰佛里·巴瓦的风景园林设计探索之路解析

斯里兰卡著名建筑师与风景园林师杰佛里·巴瓦勇于探索建筑设计与风景园林设计的关系,其风景园林设计作品在国际风景园林界产生了很好的影响,有人称赞他为建筑与风景园林设计的结合,走出了成功的一步。他在经济并不发达、政治与民族关系纷繁复杂的斯里兰卡,默默无闻地执著工作,并最终获得成功,同时也得到世人的认可。巴瓦的才华是有目共睹的,他执著的精神和强烈的责任感,更加值得世人敬佩和学习。通过探讨他的设计理念和设计方法,试图从中找到其成功答案——如何走上乡土之路。     

甘青川滇藏区传统地域建筑文化的多元性

特殊的地理和文化区位造成了甘青川滇藏区建筑文化的多元性特征,而建筑文化的多样性是形成本地区传统地域建筑丰富类型的重要因素,同时,丰富的建筑类型也是文化多样性在建筑领域的集中体现.对历史沿革、文化背景与西藏地区有着显著差异的甘青川滇藏区的传统地域建筑进行深入研究,不仅有助于西藏建筑研究和解决西北及西南地区建筑研究中某些跨区域问题,也可深化对整个藏区建筑格局的认识.     

当代国外教学空间组织启示

新的时代呼唤新的教育理念，新的教育理念需要新型教学空间。该文借鉴国外中小学教学空间实例，试从“办公——教室”、“教室——教室”、教室内部三个层次探讨新型教学空间的组织模式。     

大卫·奇普菲尔德的多样性建筑设计

英国建筑师大卫·奇普菲尔德的设计作品体现出对设计对象深刻理解基础上的多样性。本文通过对他的代表性作品的描述,讨论了他在设计中对材料和细部的重视,对地方性和乡土性的把握,以及面对特殊历史文脉时的“连续性”设计策略;并分析了他在设计中所表现出来的“极少主义”以及人性化的特征。     

营造充满活力的多样化空间形态——以呼和浩特托电工业园综合服务区修建性详细规划为例

在呼和浩特托电工业园综合服务区的规划设计中，通过用地功能的混合和多样化、人性化的道路交通系统、绿化水景的多样化、景观环境的多样化和富有特色的多样化居住形态，从而创造充满活力的多样化的空间形态，以满足人们生活多样化的需求.