Bioinspired Infrared Sensing Materials and Systems

Bioinspired engineering offers a promising alternative approach in accelerating the development of many man‐made systems. Next‐generation infrared (IR) sensing systems can also benefit from such nature‐inspired approach. The inherent compact and uncooled operation of biological IR sensing systems provides ample inspiration for the engineering of portable and high‐performance artificial IR sensing systems. This review overviews the current understanding of the biological IR sensing systems, most of which are thermal‐based IR sensors that rely on either bolometer‐like or photomechanic sensing mechanism. The existing efforts inspired by the biological IR sensing systems and possible future bioinspired approaches in the development of new IR sensing systems are also discussed in the review. Besides these biological IR sensing systems, other biological systems that do not have IR sensing capabilities but can help advance the development of engineered IR sensing systems are also discussed, and the related engineering efforts are overviewed as well. Further efforts in understanding the biological IR sensing systems, the learning from the integration of multifunction in biological systems, and the reduction of barriers to maximize the multidiscipline collaborations are needed to move this research field forward.     

某楼宇设备自控系统的安装与监控

楼宇自控系统主要包括对空调冷热源系统、空调新风系统、高位水箱给水系统和照明系统等进行监控和管理.中央空调系统设备的节能、高效对整个建筑的节能有重要的意义;建筑水电的状态、参数进行监测与控制,是保证系统的运行参数满足供水照明要求以及供水照明系统的安全和节约能源.     

富勒烯和碳纳米管在润滑体系中的研究进展

纳米材料改善润滑体系是摩擦学研究的热点之一.综述了富勒烯和碳纳米管改善流体润滑体系、固体润滑体系(固体膜、碳基、聚合物基、金属基、陶瓷基润滑体系)摩擦性能的研究进展.富勒烯和碳纳米管可使体系的摩擦系数减小、磨损率减小、硬度增大,从而优化摩擦性能.富勒烯和碳纳米管具有优良的自润滑性,有成为"分子滚珠(轴)"润滑添加剂的潜力.     

Improved Systems Understanding by Similarities and Analogies

ABSTRACT

A set of definitions of systems engineering concepts is the point of departure of this article. Those definitions are generic and cover the system and its life cycle, the systems engineering discipline, and the systems engineering process. A systems engineer must be able to analyze and understand systems first on a conceptual level independent of technology, that is, a technology-free functional analysis. More detailed knowledge and deeper insight into a concrete technology are required later. The systems engineer must be able to move from one system project to another, sometimes with entirely different technologies and requirements. This article points to a need for greater flexibility and easier adaptability on the part of the systems engineer. This need implies that the knowledge base and professional toolbox for the systems engineer must meet this requirement also. A way this requirement can be met is by system similarity and the principle of analogy between functional characteristics of systems.     

Permanence criteria in non-autonomous predator-prey Kolmogorov systems and its applications

The paper studies the general non-autonomous predator-prey Kolmogorov systems. The general criteria of integrable form on the permanence and ultimate boundedness are established. As applications of these results, the sufficient conditions of integrable form on the permanence are obtained for non-autonomous Lotka-Volterra systems, Holling I-type functional response systems, Holling (m, n)-type functional response systems, Beddington-DeAngelis functional response systems, Leslie-Gower functional response systems and chemostat-type systems.     

Boarding and alighting injury experience with different station platform and car entranceway designs on US commuter railroads

Commuter railroad systems in the US employ three combinations of station platforms and car entranceways. These are high-level platforms with remotely controlled doors and level entranceway (HL-RC), low-level platforms (just above the rail) with steps and remotely controlled doors (LL-RC), and a mixture of the two platform types with a correspondingly more complex, partly manual, door and entranceway arrangement (ML-MO). Much controversy exists over which type of platform/entranceway is better. This seemingly small feature significantly impacts many performance characteristics of these systems, including cost, speed, and boarding and alighting accidents. Northeastern systems are generally moving toward the mixed platform design or all high-level platforms, while systems elsewhere are generally selecting the low-level design. Data on actual accident experience for 1995-2000 are analyzed to determine the effect of platform/entranceway type on passenger and employee injuries. Passenger injury rates on systems with the HL-RC design are lowest, with LL-RC systems next, and ML-MO systems having the highest rates. Employee injury rates are the least on LL-RC systems, but higher on ML-MO and HL-RC systems. Systems with a mixture of high and low platforms (ML-MO) experience a higher overall (combined passenger and employee) injury rate than the other two designs. The implications of these results for both the modernization of existing systems and the design of new systems, in the US and abroad, are discussed.     

The initial motions for holonomic and nonholonomic mechanical systems

Whittaker first put forward a new approach, called the initial motions, to solve the differential equations of motion aimed at holonomic systems. Since most of the differential equations of motion for mechanical systems are nonlinear ordinary ones, which are difficult to find the analytic solutions. Fortunately, the concept of initial motions can manage these situations and study its subsequent motions. This work is devoted to discuss and investigate the initial motions for mechanical systems, particularly for nonholonomic systems. First, the differential equations for holonomic systems are formulated, and the formulation and solution of initial motions of the systems are proposed. Second, the differential equations of motion for nonholonomic systems are established, based on the new method of initial motions to obtain the initial values of high-order derivatives of generalized velocities, the formulation and solution of initial motions are introduced in the general nonholonomic systems and Chaplygin systems. The methods and results obtained are illustrated by a number of classical examples, both for holonomic and nonholonomic systems.     

Push and pull strategies for controlling multistage production systems

This study considers push and pull strategies to control multistage production systems with random processing times. Such systems are important as they mirror the level of complexity often encountered in practice. We start with definitions of push and pull systems, and develop a framework to compare multistage production systems based upon work-in-process (WIP) and throughput (TP) tradeoff. Surprisingly, we find that often push out performs pull, i.e. push systems accumulate less WIP than pull systems, while maintaining higher PT Concerning pull systems we find that WIP linearly increases in the number of stages and that WIP is not affected by variation in processing time. Concerning push systems we find that the release of material into the system in deterministic time intervals greatly improves performance.     

Imaging systems and applications

Imaging systems are used in consumer, medical, and military applications. Designing, developing, and building imaging systems requires a multidisciplinary approach. This issue features current research in imaging systems that ranges from fundamental theories to novel applications. Although the papers collected are diverse, their unique compilation provides a systems perspective to imaging.     

Design and operating characteristics of evaporative cooling systems

Evaporative cooling systems are commonly used in countries where the climate is hot and dry, as found in most zones of India and Australia. The potential energy savings envisaged by replacing conventional refrigerated systems by evaporative systems is ≈75%. Indirect systems can achieve comfort conditions similar to refrigerated systems in climatic zones where the wet bulb temperature is usually <25°C. The comfort afforded by indirect evaporative systems is superior to that achieved by direct evaporative systems. An 8.5 ton indirect-direct evaporative cooling system has been fabricated and tested and its performance compared with a computer prediction. The system's scope for use in India and Australia is analysed.     

Organizing and coordinating talk and silence in organizations

The computer stores mountains of information that it communicatesworldwide through an enormous bandwidth. We must learn to exercisesevere, intelligent selectivity in mining our data mountains,and to communicate information in ways that will inform andnot bury the recipients. This is today's task of organizationaldesign. Organizing combines human efforts efficiently, dividingthe undertaking into separate but interdependent tasks and securinggood coordination in their performance. An effective organizationand its buildings balance opportunity for reflective deliberationagainst opportunity for mutual exchange of ideas and information.That balance is lost if talk drowns out silence. In our time,silence is unlikely to drown out talk. In recent years, we have been learning a great deal about thegeneral nature and organization of complex systems. We ourselvesare complex systems and we are surrounded by a host of othercomplex systems: social, technical and natural. Among the importantsocial systems are business and non-profit organizations, ona smaller scale families, and on a larger scale, ethnic groupsand nations. Among the important technical systems are machines,buildings of innumerable kinds and electronic networks. Amongthe important natural systems are multicelled organisms andecosystems.     

Equilibrium and non-equilibrium wetting

The influence of mass transfer and chemical reactions on wetting has been studied using metal systems and aqueous solution systems to determine the equilibrium wetting. The influence of mass transfer on wetting has been studied using Al/Si systems and aqueous solution/NaCl systems and the influence of chemical reactions is discussed using Al/Ni systems and aqueous solution/B₂O₃ systems. The reaction products in the Al/Ni system change with temperature to NiAl₃, Ni₂Al₃ and NiAl, and the reaction product for the aqueous solution/B₂O₃ system is B(OH)₃.We also discuss the influence of relative humidity on wetting in the aqueous solution systems. The results show that the contact angle is highest under equilibrium humidity conditions.     

Recurrent motions and global attractors of non-autonomous Lorenz systems

This paper is devoted to the study of dynamics of non-autonomous Lorenz systems. These systems are formulated and investigated in the context of non-autonomous dynamical systems. First, we prove that such systems admit a compact global attractor and characterize its structure. Then, we obtain conditions of convergence, under which all solutions of the non-autonomous Lorenz systems approach a point attractor. Third, we derive a criterion for existence of almost periodic, quasi-periodic, periodic, and recurrent motions. Finally, we prove a global averaging principle for non-autonomous Lorenz systems.     

Viewpoint: From Responsive to Adaptive and Interactive Materials and Materials Systems: A Roadmap

Soft matter systems and materials are moving toward adaptive and interactive behavior, which holds outstanding promise to make the next generation of intelligent soft materials systems inspired from the dynamics and behavior of living systems. But what is an adaptive material? What is an interactive material? How should classical responsiveness or smart materials be delineated? At present, the literature lacks a comprehensive discussion on these topics, which is however of profound importance in order to identify landmark advances, keep a correct and noninflating terminology, and most importantly educate young scientists going into this direction. By comparing different levels of complex behavior in biological systems, this Viewpoint strives to give some definition of the various different materials systems characteristics. In particular, the importance of thinking in the direction of training and learning materials, and metabolic or behavioral materials is highlighted, as well as communication and information-processing systems. This Viewpoint aims to also serve as a switchboard to further connect the important fields of systems chemistry, synthetic biology, supramolecular chemistry and nano- and microfabrication/3D printing with advanced soft materials research. A convergence of these disciplines will be at the heart of empowering future adaptive and interactive materials systems with increasingly complex and emergent life-like behavior.     

非线性振动 分叉和混沌理论及其应用

本文主要是从非线性振动的角度出发综述了近年来国内外在非线性振动、分叉和混沌理论及其应用方面的主要成果和发展前景。首先,本文回顾了非线性振动理论的历史,阐述了应用分叉和混沌理论研究非线性振动系统的必要性,进而给出了近期非线性振动八个重点方面的研究方向。其次,我们详细地综述了非线性振动系统的解析方法、非线性振动系统的局部分叉理论及分析方法、非线性振动系统的全局分叉及混沌、非线性随机系统的振动与分叉理论四个方面近期国内外研究工作的主要成果和进展。最后,本文说明了今后分叉和混沌及其应用于非线性振动的主要研究内容。     

供应链系统仿真模型及优化

采用系统仿真的思想对供应链系统进行研究.建立了包括供应商、制造商及零售商的供应链系统仿真模型并对其进行了优化.通过运行该模型,可研究供应链系统的动态行为;分析随机因素对供应链系统的影响;识别供应链系统的瓶颈.仿真优化结果为管理者正确决策提供依据.     

制造及其系统的创新与管理的发展

从制造业面临的形势分析出发,介绍了先进制造战略、技术、制造系统与系统管理的最新研究成果。并指出在建立现代企业制度中,制造战略、产品开发、质量保证和优化动作是３个增强竞争力的基本技术。     

Design and operation of single-loop dual-rail inter-bay material handling system

Asynchronized automated material handling systems, e.g. automated electrified monorail systems and automated guided vehicle systems, have been playing important roles in manufacturing. Reliability becomes a critical issue as manufacturing enterprises are moving toward automation. In the past, reliability tissue has not been analysed explicitly for these types of systems. In this research, a new measure was proposed to specify reliability. A mixed integer programming model was developed to design flow paths for a special class of material handling systems, i.e. single-loop dual-rail systems. The model can be used to design systems with higher reliability. The model and application procedure in design and analysis were demonstrated through two case studies.     

Mixed valence and superconductivity

Mixed-valence (MV) systems are referred to here as MV-2 and MV-3 depending on whether two or three consecutive valence states are involved. MV-3 systems range from systems with Hubbard U>0, corresponding to a single stable, intermediate valence state, and U<0, corresponding to stable alternating valences differing by two units. Experiments using inelastic neutron scattering or inelastic X-ray scattering show softening of breathing phonon modes in MV systems compared with related systems with a single valence. It is hypothesized that softening is due to coupling between potential energy surfaces, corresponding to differing localizations of the electron. As predicted, softening is larger in the delocalized case. A mechanism for superconductivity is suggested.