This review discusses how low-energy, valence excitations created by swift electrons can render information on the optical response of structured materials with unmatched spatial resolution. Electron microscopes are capable of focusing electron beams on sub-nanometer spots and probing the target response either by analyzing electron energy losses or by detecting emitted radiation. Theoretical frameworks suited to calculate the probability of energy loss and light emission (cathodoluminescence) are revisited and compared with experimental results. More precisely, a quantum-mechanical description of the interaction between the electrons and the sample is discussed, followed by a powerful classical dielectric approach that can be in practice applied to more complex systems. We assess the conditions under which classical and quantum-mechanical formulations are equivalent. The excitation of collective modes such as plasmons is studied in bulk materials, planar surfaces, and nanoparticles. Light emission induced by the electrons is shown to constitute an excellent probe of plasmons, combining sub-nanometer resolution in the position of the electron beam with nanometer resolution in the emitted wavelength. Both electron energy-loss and cathodoluminescence spectroscopies performed in a scanning mode of operation yield snap shots of plasmon modes in nanostructures with fine spatial detail as compared to other existing imaging techniques, thus providing an ideal tool for nanophotonics studies.

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Optical excitations in electron microscopy

ZnS nanostructures: From synthesis to applications

A thin-film, white-light-emitting diode device includes a reflective, conductive thin-film structure and a semi-transparent, conductive thin-film structure One or more thin-film layers are formed between the reflective and semi-transparent conductive thin-film structures to form two or more commonly-controlled microcavity structures The thin-film layers emit white light in response to current provided by the conductive thin-film structure Each of the two or more commonly-controlled microcavity structures has a different resonant frequency within one or more optical cavities and emits light with a smaller spectral range than the spectral range of the white-light-emitting thin-film layer(s) A combination of light emitted from the two or more commonly-controlled microcavity structures is white

Oled device having improved light output

A touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area and a second region micropattern. The first region micropattern has a first sheet resistance value in a first direction, is visible light transparent, and has at least 90% open area. The second region micropattern has a second sheet resistance value in the first direction. The first sheet resistance value is different from the second sheet resistance value.

Touch screen sensor

A touch screen display sensor is provided that includes a transparent touch-sensing element disposed upon the surface of a transparent substrate and a force-sensing element disposed within the transparent touch-sensing element. The force-sensing element includes two sets of bands of micromesh and can include a pressure-responsive material between the bands of micromesh. The bands of micromesh include traces of a metallic conductor. The sets of bands of micromesh are spaced apart and occupy substantially parallel planes.

Positional touch sensor with force measurement

A 20-inch, largest OLED display in the world is demonstrated which is driven by “Super Amorphous Silicon” technology. It has been widely believed that the characteristics of amorphous silicon TFT is not sufficient to drive OLED display. This paper turns over the hypothesis to prove that amorphous silicon can be applied to the large active-matrix driven displays. Novel approaches to enable amorphous silicon to drive bright and long life OLED display are shown to open a bright future to realize larger OLED televisions.

4.1: A 20-inch OLED Display Driven by Super-Amorphous-Silicon Technology

To successfully support multimedia applications, it is necessary to improve the state-of-theart multimedia technologies and multimedia transmissions over communication networks in order to provide quality-of-service (QoS) guarantees between end-users and to achieve a high quality-of-experience for end-users. The accepted papers in this special issue deal with a wide range of important aspects and challenging issues of communication networks and multimedia technologies, and the contents are built on analytical modelling, experimental and simulation studies. The contributions of these papers are outlined below. With the development of wireless access and multimedia compression technologies, much attention has been devoted to wireless video communications. Wan, Xiong and Yang propose an integrated routing metric to evaluate path quality taking the hop count, congestion bottleneck and other parameters of a path into account. They design the traffic assignment and traffic adjustment modules to make the routing scheme flexible to the changing environments, and present an enhanced link layer scheduling algorithm. Simulation results show that compared to commonly used schemes, the proposed network layer scheme always provides better performance with various traffic modes; combined with link layer scheduling algorithm, the performance could be further improved. High speed and quality multimedia and data transmission requirements exist widely in wireless networks. Wang et al. investigate the performance of opportunistic scheduling in wireless multimedia and data networks based on popular stochastic network calculus (SNC). The authors firstly bound the traffic arrival process using the exponentially bounded burstiness traffic model of SNC and establish a stochastic arrival curve, and then propose a new wireless opportunistic scheduling, i.e., modified proportional fairness (MPF) scheduling algorithm, which can provide better fairness for input traffic to guarantee QoS performance, and obtain a stochastic service curve. The numerical results show that the proposed stochastic model and MPF scheduling algorithm can provide better QoS performance. Multimed Tools Appl (2015) 74:1–3 DOI 10.1007/s11042-013-1647-x

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Editorial: recent advances in communication networks and multimedia technologies

An electrode for an electro-optical device is provided. Light is passing through this electrode which comprises a pattern of conductive elements. The elements have dimensions small compared to the wavelength of light, so that the electrode appear transparent. The light intensity distribution after having penetrated the electrode compared with the light intensity distribution before having penetrated the electrode is influenced by forward scattering.

Electrode for use in electro-optical devices

The electronic excitation spectrum of ZnS nanowires (NWs) is characterized by cathodoluminescence (CL) excited using the tip of a scanning tunneling microscope as a highly localized and bright source of low-energy (150−350 eV) electrons with impinging power densities in the range of up to 60 kW/cm2 or more. The CL spectra reveal significant differences when compared with the photoluminescence spectra of ZnS NWs. The differences can be associated with the properties of the surface region of the NWs, which are preferentially emphasized in the CL spectra owing to the small probing depth of low-energy electrons.

Scanning tunneling microscope excited cathodoluminescence from ZnS nanowires.

Cloud computing systems and services have become major targets for cyberattackers. To provide strong protection of cloud platforms, infrastructure, hosted applications, and data stored in the cloud, we need to address the security issue from a range of perspectives-from secure data and application outsourcing, to anonymous communication, to secure multiparty computation. This special issue on cloud security aims to address the importance of protecting and securing cloud platforms, infrastructures, hosted applications, and data storage.

http://ieeexplore.ieee.org/iel7/6509491/7742214/07742293.pdf

Peter Mueller

Papers

4.1: A 20-inch OLED Display Driven by Super-Amorphous-Silicon Technology

Editorial: recent advances in communication networks and multimedia technologies

Electrode for use in electro-optical devices

Scanning tunneling microscope excited cathodoluminescence from ZnS nanowires.

Cloud Security