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Background Since at least 400 C.E., when the Mayans first used layered clays to make dyes, people have been harnessing the properties of layered materials. This gradually developed into scientific research, leading to the elucidation of the laminar structure of layered materials, detailed understanding of their properties, and eventually experiments to exfoliate or delaminate them into individual, atomically thin nanosheets. This culminated in the discovery of graphene, resulting in a new explosion of interest in two-dimensional materials. Layered materials consist of two-dimensional platelets weakly stacked to form three-dimensional structures. The archetypal example is graphite, which consists of stacked graphene monolayers. However, there are many others: from MoS 2 and layered clays to more exotic examples such as MoO 3 , GaTe, and Bi 2 Se 3 . These materials display a wide range of electronic, optical, mechanical, and electrochemical properties. Over the past decade, a number of methods have been developed to exfoliate layered materials in order to produce monolayer nanosheets. Such exfoliation creates extremely high-aspect-ratio nanosheets with enormous surface area, which are ideal for applications that require surface activity. More importantly, however, the two-dimensional confinement of electrons upon exfoliation leads to unprecedented optical and electrical properties. Advances An important advance has been the discovery that layered crystals can be exfoliated in liquids. There are a number of methods to do this that involve oxidation, ion intercalation/exchange, or surface passivation by solvents. However, all result in liquid dispersions containing large quantities of nanosheets. This brings considerable advantages: Liquid exfoliation allows the formation of thin films and composites, is potentially scaleable, and may facilitate processing by using standard technologies such as reel-to-reel manufacturing. Although much work has focused on liquid exfoliation of graphene, such processes have also been demonstrated for a host of other materials, including MoS 2 and related structures, layered oxides, and clays. The resultant liquid dispersions have been formed into films, hybrids, and composites for a range of applications. Outlook There is little doubt that the main advances are in the future. Multifunctional composites based on metal and polymer matrices will be developed that will result in enhanced mechanical, electrical, and barrier properties. Applications in energy generation and storage will abound, with layered materials appearing as electrodes or active elements in devices such as displays, solar cells, and batteries. Particularly important will be the use of MoS 2 for water splitting and metal oxides as hydrogen evolution catalysts. In addition, two-dimensional materials will find important roles in printed electronics as dielectrics, optoelectronic devices, and transistors. To achieve this, much needs to be done. Production rates need to be increased dramatically, the degree of exfoliation improved, and methods to control nanosheet properties developed. The range of layered materials that can be exfoliated must be expanded, even as methods for chemical modification must be developed. Success in these areas will lead to a family of materials that will dominate nanomaterials science in the 21st century.

The future communication technologies are naturally evolving towards higher carrier frequencies in order to satisfy the demand for increasing data rates. Terahertz frequencies appear to make high speed and high data rate communications possible. However, due to the high free-space damping above 100 GHz, communication systems are limited to short range, seldom, non-line-of-sight transmission links which rely mostly on the reflection properties of walls and other surfaces. We have investigated the scattering coefficients of a representative collection of fifty building materials used for construction. The optical and reflection properties of the samples were measured using terahertz time-domain spectroscopy and the scattering coefficients were modeled based on the Fresnel-Rayleigh equations and the Kirchhoff theory. The proposed Kirchhoff-Rayleigh approach is appropriate for the scattering characterisation of rough surfaces with limitations to resolve the scattering coefficients of materials with a complex structure. Nonetheless, the measured data show the reflection potential of materials commonly found in indoor environments, giving important insight into the further modeling of THz communication channels.

Dielectric ceramic materials have been studied for decades due to both their application in important technologies and the fundamentally interesting relationships among their crystal chemistry, crystal structures, and physical properties. Recent dramatic changes in microelectronics and in particular wireless communications technologies have made the importance of materials with the unusual combination of high dielectric constant, low dielectric loss and low temperature dependence of dielectric constant of great interest. In this review, the present state of knowledge of the chemistry, structure, and dielectric properties of these materials, as well as examples of our own work, are described.

MIMO-OFDM is a key technology for next-generation cellular communications (3GPP-LTE, Mobile WiMAX, IMT-Advanced) as well as wireless LAN (IEEE 802.11a, IEEE 802.11n), wireless PAN (MB-OFDM), and broadcasting (DAB, DVB, DMB). In MIMO-OFDM Wireless Communications with MATLAB, the authors provide a comprehensive introduction to the theory and practice of wireless channel modeling, OFDM, and MIMO, using MATLAB programs to simulate the various techniques on MIMO-OFDM systems. One of the only books in the area dedicated to explaining simulation aspects Covers implementation to help cement the key concepts Uses materials that have been classroom-tested in numerous universities Provides the analytic solutions and practical examples with downloadable MATLAB codes Simulation examples based on actual industry and research projects Presentation slides with key equations and figures for instructor use MIMO-OFDM Wireless Communications with MATLAB is a key text for graduate students in wireless communications. Professionals and technicians in wireless communication fields, graduate students in signal processing, as well as senior undergraduates majoring in wireless communications will find this book a practical introduction to the MIMO-OFDM techniques. Instructor materials and MATLAB code examples available for download at www.wiley.com/go/chomimo

Natural structural color materials, especially those that can undergo reversible changes, are attracting increasing interest in a wide variety of research fields. Inspired by the natural creatures, many elaborately nanostructured photonic materials with variable structural colors were developed. These materials have found important applications in switches, display devices, sensors, and so on. In this critical review, we will provide up-to-date research concerning the natural and bio-inspired photonic materials with variable structural colors. After introducing the variable structural colors in natural creatures, we will focus on the studies of artificial variable structural color photonic materials, including their bio-inspired designs, fabrications and applications. The prospects for the future development of these fantastic variable structural color materials will also be presented. We believe this review will promote the communications among biology, bionics, chemistry, optical physics, and material science (196 references).

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Abstract The rapidly increasing number of mobile devices, voluminous data, and higher data rate is pushing the development of the fifth-generation (5G) wireless communications. The 5G networks are broadly characterized by three unique features: ubiquitous connectivity, extremely low latency, and very high-speed data transfer via adoption of new technology to equip future millimeter band wireless communication systems at nanoscale and massive multi-input multi-output (MIMO) with extreme base station and device densities, as well as unprecedented numbers of nanoantennas. In this article, these new technologies of 5G are presented so as to figure out the advanced requirements proposed for the nanomaterials applied to antennas in particular. Because of massive MIMO and ultra-densification technology, conventional antennas are unable to serve the new frequency for smaller sizes, and the nanoantennas are used in 5G. The nanomaterials for nanoantennas applied in wideband millimeter waves are introduced. Four types of nanomaterials including graphene, carbon nanotubes, metallic nanomaterials, and metamaterials are illustrated with a focus on their morphology and electromagnetic properties. The challenges for the commercialization of 5G and nanomaterials are also discussed. An atomistic modeling approach is proposed for the development of novel nanomaterials applied in 5G and beyond.

In addition to the constant demand of low-loss dielectric materials for wireless telecommunication, the recent progress in the Internet of Things (IoT), the Tactile Internet (fifth generation wireless systems), the Industrial Internet, satellite broadcasting and intelligent transport systems (ITS) has put more pressure on their development with modern component fabrication techniques. Oxide ceramics are critical for these applications, and a full understanding of their crystal chemistry is fundamental for future development. Properties of microwave ceramics depend on several parameters including their composition, the purity of starting materials, processing conditions and their ultimate densification/porosity. In this review the data for all reported low-loss microwave dielectric ceramic materials are collected and tabulated. The table of these materials gives the relative permittivity, quality factor, temperature variation of the resonant frequency, crystal structure, sintering temperature, measurement frequency and references. In addition, the methods commonly employed for measuring the microwave dielectric properties, important from the applications point of view, factors affecting the dielectric loss, methods to tailor the dielectric properties and materials for future applications, are briefly described. The data will be very useful for scientists, industrialists, engineers and students working on current and emerging applications of wireless communications.

From the Publisher: The most recent addition to William C. Y. Lee's acclaimed series on mobile and cellular communications, Mobile Communications Design Fundamentals, Second Edition offers designers, researchers, and students an up-to-date, invaluable guide to the theoretical framework of mobile radio communications and how such systems are designed. With an abundance of new material, this Second Edition covers leading-edge Personal Communications Service (PCS), microcell, and CDMA systems, providing all the theoretical and design knowledge and know-how needed to design with both present and future technology. Useful as a professional handbook or as a senior/graduate level text, the book provides complete coverage of the differences between fixed and wireless radio systems, up to and including the new FCC-promoted PCS systems; an authoritative description of the mobile radio environment that gives engineers the necessary technical background to confidently select the appropriate radio technology; definitive, clearly presented design parameters for both the base and mobile units; troubleshooting approaches that help you anticipate the problems associated with each system and solve them when they arise; comprehensive guidelines for how to develop the system design and frequency plan and how to tackle all capacity issues, and new information on CDMA, a hot broadband radio technology...boosting microcell technology capacity with system planning...built in prediction...analyzing digital communication systems...and covering noncellular mobile radio systems, including those for data communication. With more than half of the material in this new edition based on the author's own widely recognized research work, Mobile Communications Design Fundamentals is a book no one interested in the new wave in mobile communications can afford to miss.

CONTEXT: Although physicians' communication skills have been found to be related to clinical outcomes and patient satisfaction, teaching of communication skills has not been fully integrated into many medical school curricula or adequately evaluated with large-scale controlled trials. OBJECTIVE: To determine whether communications training for medical students improves specific competencies known to affect outcomes of care. DESIGN AND SETTING: A communications curriculum instituted in 2000-2001 at 3 US medical schools was evaluated with objective structured clinical examinations (OSCEs). The same OSCEs were administered to a comparison cohort of students in the year before the intervention. PARTICIPANTS: One hundred thirty-eight randomly selected medical students (38% of eligible students) in the comparison cohort, tested at the beginning and end of their third year (1999-2000), and 155 students in the intervention cohort (42% of eligible students), tested at the beginning and end of their third year (2000-2001). INTERVENTION: Comprehensive communications curricula were developed at each school using an established educational model for teaching and practicing core communication skills and engaging students in self-reflection on their performance. Communications teaching was integrated with clinical material during the third year, required clerkships, and was supported by formal faculty development. MAIN OUTCOME MEASURES: Standardized patients assessed student performance in OSCEs on 21 skills related to 5 key patient care tasks: relationship development and maintenance, patient assessment, education and counseling, negotiation and shared decision making, and organization and time management. Scores were calculated as percentage of maximum possible performance. RESULTS: Adjusting for baseline differences, students exposed to the intervention significantly outperformed those in the comparison cohort on the overall OSCE (65.4% vs 60.4%; 5.1% difference; 95% confidence interval [CI], 3.9%-6.3%; P<.001), relationship development and maintenance (5.3% difference; 95% CI, 3.8%-6.7%; P<.001), organization and time management (1.8% difference; 95% CI, 1.0%-2.7%; P<.001), and subsets of cases addressing patient assessment (6.7% difference; 95% CI, 5.9%-7.8%; P<.001) and negotiation and shared decision making (5.7% difference; 95% CI, 4.5%-6.9%; P<.001). Similar effects were found at each of the 3 schools, though they differed in magnitude. CONCLUSIONS: Communications curricula using an established educational model significantly improved third-year students' overall communications competence as well as their skills in relationship building, organization and time management, patient assessment, and negotiation and shared decision making-tasks that are important to positive patient outcomes. Improvements were observed at each of the 3 schools despite adaptation of the intervention to the local curriculum and culture.

The current state-of-the-art of nonlinear optical materials suitable for ultrafast all-optical applications is discussed. This survey will include progress in the third-order nonlinear properties of semiconductors, polymers and glasses and examples of their applications to devices. Also discussed will be 'cascading', a second-order nonlinearity-based approach to all-optical effects.

The 2nd Edition of Optical Wireless Communications: System and Channel Modelling with MATLAB® with additional new materials, is a self-contained volume that provides a concise and comprehensive coverage of the theory and technology of optical wireless communication systems (OWC). The delivery method makes the book appropriate for students studying at undergraduate and graduate levels as well as researchers and professional engineers working in the field of OWC. The book gives a detailed description of OWC, focusing mainly on the infrared and visible bands, for indoor and outdoor applications. A major attraction of the book is the inclusion of Matlab codes and simulations results as well as experimental test-beds for free space optics and visible light communication systems. This valuable resource will aid the readers in understanding the concept, carrying out extensive analysis, simulations, implementation and evaluation of OWC links. This 2nd edition is structured into nine compact chapters that cover the main aspects of OWC systems: History, current state of the art and challenges Fundamental principles Optical source and detector and noise sources Modulation, equalization, diversity techniques Channel models and system performance analysis Visible light communications Terrestrial free space optics communications Relay-based free space optics communications Matlab codes. A number of Matlab based simulation codes are included in this 2nd edition to assist the readers in mastering the subject and most importantly to encourage them to write their own simulation codes and enhance their knowledge.

A self-supporting zeolite NaA membrane has been synthesized from an initially homogeneous hydrothermal solution. Membranes ca. 7 µm thick were formed successfully on polyethylene, glass and poly(tetrafluoroethylene) substrates.

R. J. P. Corriu, D. Leclercq, P. Lefèvre, P. H. Mutin and A. Vioux, J. Mater. Chem., 1992, 2, 673 DOI: 10.1039/JM9920200673

M. A. Hamstra, H. F. Folkerts and G. Blasse, J. Mater. Chem., 1994, 4, 1349 DOI: 10.1039/JM9940401349

This newly revised and greatly expanded edition of the popular Artech House book, Modern Communications Jamming Principles and Techniques, provides an up-to-date, exhaustive treatment of the techniques and methods available to create countermeasures against anti-jam, over-the-air communications. The Second Edition features a wealth of new material on urban warfare, including a computer simulation of EW architecture alternatives for land-based forces based on urban constraints. The new edition also includes an expanded section on time-hopped spread spectrum communications, more details on modern communication system technologies such as CDMA and OFDM, and an in-depth discussion on sources of urban noise. This practical resource is focused on showing you how to design and build jammers specifically targeted at spread spectrum, anti-jam communications. Moreover, you find assistance in evaluating the expected performance of jamming systems against modern communications systems, and discover the best waveform to use to counter communication systems designed to be effective in jamming environments. While mathematical derivations in general are avoided, the book presents error rate performance equations for most modern digital anti-jam communication systems.

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Professor Andreas F. Molisch, renowned researcher and educator, has put together the comprehensive book, Wireless Communications. The second edition, which includes a wealth of new material on important topics, ensures the role of the text as the key resource for every student, researcher, and practitioner in the field.Professor Moe Win, MIT, USAWireless communications has grown rapidly over the past decade from a niche market into one of the most important, fast moving industries. Fully updated to incorporate the latest research and developments, Wireless Communications, Second Edition provides an authoritative overview of the principles and applications of mobile communication technology.The author provides an in-depth analysis of current treatment of the area, addressing both the traditional elements, such as Rayleigh fading, BER in flat fading channels, and equalisation, and more recently emerging topics such as multi-user detection in CDMA systems, MIMO systems, and cognitive radio. The dominant wireless standards; including cellular, cordless and wireless LANs; are discussed.Topics featured include: wireless propagation channels, transceivers and signal processing, multiple access and advanced transceiver schemes, and standardised wireless systems.Combines mathematical descriptions with intuitive explanations of the physical facts, enabling readers to acquire a deep understanding of the subject.Includes new chapters on cognitive radio, cooperative communications and relaying, video coding, 3GPP Long Term Evolution, and WiMax; plus significant new sections on multi-user MIMO, 802.11n, and information theory.Companion website featuring: supplementary material on 'DECT', solutions manual and presentation slides for instructors, appendices, list of abbreviations and other useful resources.

QUANTUM ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave). The acronym ESPRESSO stands for opEn Source Package for Research in Electronic Structure, Simulation, and Optimization. It is freely available to researchers around the world under the terms of the GNU General Public License. QUANTUM ESPRESSO builds upon newly-restructured electronic-structure codes that have been developed and tested by some of the original authors of novel electronic-structure algorithms and applied in the last twenty years by some of the leading materials modeling groups worldwide. Innovation and efficiency are still its main focus, with special attention paid to massively parallel architectures, and a great effort being devoted to user friendliness. QUANTUM ESPRESSO is evolving towards a distribution of independent and interoperable codes in the spirit of an open-source project, where researchers active in the field of electronic-structure calculations are encouraged to participate in the project by contributing their own codes or by implementing their own ideas into existing codes.