Optimal DLC protocol configuration for realistic broadband fixed wireless access networks based on ATM

DLC protocols, scheduling, and multiplexing issues for broadband fixed wireless access networks based on ATM are discussed. The established DSA++ mac protocol has been developed at ComNets and has been widely applied within the German project ATMmobil. It has been a fundamental contribution to the etsi bran standardisation of HIPERLAN /2. The DSA++ is here modified to perform optimal within the fixed wireless access network environment. Therefore, realistic traffic as well as radio channel models for the respective scenarios are introduced. Simulation results are presented, showing the feasibility of the respective protocol stack for offering broadband multimedia services with reasonable quality of service. In addition to this advanced protocol approach, two systems are discussed which are currently under standardisation process. The IEEE 802.16 as well as the European hiperaccess systems are both proposed for fixed wireless access networks. Expected scenarios and applications are presented and basic requirements the standards have to fulfil are derived. As another aspect of access networks, their impact on the global information society is discussed.     

Area, Delay, and Power Characteristics of Standard-Cell Implementations of the AES S-Box

Cryptographic substitution boxes (S-boxes) are an integral part of modern block ciphers like the Advanced Encryption Standard (AES). There exists a rich literature devoted to the efficient implementation of cryptographic S-boxes, wherein hardware designs for FPGAs and standard cells received particular attention. In this paper we present a comprehensive study of different standard-cell implementations of the AES S-box with respect to timing (i.e. critical path), silicon area, power consumption, and combinations of these cost metrics. We examine implementations which exploit the mathematical properties of the AES S-box, constructions based on hardware look-up tables, and dedicated low-power solutions. Our results show that the timing, area, and power properties of the different S-box realizations can vary by up to almost an order of magnitude. In terms of area and area-delay product, the best choice are implementations which calculate the S-box output. On the other hand, the hardware look-up solutions are characterized by the shortest critical path. The dedicated low-power implementations do not only reduce power consumption by a large degree, but they also show good timing properties and offer the best power-delay and power-area product, respectively.     

Chiral Excitonic Organic Photodiodes for Direct Detection of Circular Polarized Light

A facile route to soft matter self‐powered bulk heterojunction photodiode detectors sensitive to the circular polarization state of light is shown based on the intrinsic excitonic circular dichroism of the photoactive layer blend. As light detecting materials, enantiopure semiconducting small molecular squaraine derivates of opposite handedness are employed. Via Mueller matrix ellipsometry, the circular dichroism is proven to be of H‐type excitonic nature and not originating from mesoscopic structural ordering. Within the green spectral range, the photodiodes convert circular polarized light into a handedness‐dependent photocurrent with a maximum dissymmetry factor of ±0.1 corresponding to 5% overall efficiency for the polarization discrimination under short circuit conditions. On the basis of transfer matrix optical simulations, it is rationalized that the optical dissymmetry fully translates into a photocurrent dissymmetry for ease of device design. Thereby, the photodiode's ability to efficiently distinguish between left and right circularly polarized light without the use of external optical elements and voltage bias is demonstrated. This allows a straightforward and sustainable future design of flexible, lightweight, and compact integrated platforms for chiroptical imaging and sensing.     

Flip the tip: an automated,high quality,cost-effective patch clamp screen

The race for creating an automated patch clamp has begun. Here, we present a novel technology to produce true gigaseals and whole cell preparations at a high rate. Suspended cells are flushed toward the tip of glass micropipettes. Seal, whole-cell break-in, and pipette/liquid handling are fully automated. Extremely stable seals and access resistance guarantee high recording quality. Data obtained from different cell types sealed inside pipettes show long-term stability, voltage clamp and seal quality, as well as block by compounds in the pM range. A flexible array of independent electrode positions minimizes consumables consumption at maximal throughput. Pulled micropipettes guarantee a proven gigaseal substrate with ultra clean and smooth surface at low cost.     

Doping efficiency and energy-level scheme in C60F48-doped zinc–tetraphenylporphyrin films

High resolution synchrotron-based core level spectroscopy was used to examine the energy level alignment at the interface of zinc–tetraphenylporphyrin films doped by the surface acceptor C₆₀F₄₈. Two distinct fluorofullerene charge states were identified, corresponding to ionized and neutral molecules, and their relative concentration as a function of coverage was used to evaluate the probability of occupation of the acceptor lowest unoccupied molecular orbital (LUMO). From an initial acceptor energy of ?0.25 eV, the C₆₀F₄₈ LUMO shifts upwards with coverage due to a doping-induced interfacial dipole potential, and stabilization of the LUMO at an energy 0.45 eV above the Fermi energy was obtained. While the energy difference upon saturation is consistent with the results obtained for other donor–acceptor systems that have been interpreted as Fermi level pinning, the present work shows that the energy offset is a direct consequence of the interplay between Fermi–Dirac statistics in combination with the interfacial dipole potential.     

22 nm光刻技术前景

在国际半导体技术蓝图(ITRS)指定的22nm节点中[1],该产业将在两种竞争的光刻解决方案中进行选择,这将取决于其产品的发展路线图。在某些情况下,业界甚至可能会同时使用两种方案。这两种竞争方案就是极紫外光刻技术(EUVL)和32nm节点由193nm浸没式双重图形光刻(DPL)扩展到多图形的光刻技术。讨论了两种技术,比较了两种技术所需的关键解决方案的现状,以及存在的挑战。     

Gelation and phase separation in maltodextrin-caseinate systems

A range of rheological techniques, including small deformation isothermal runs following quenching, controlled rate heating profiles, mechanical spectra, and large deformation strain sweeps and creep compliance testing, were employed in the investigation of maltodextrin—sodium caseinate aqueous dispersions. The concentration dependence, viscoelastic ratio and melting profiles of shear moduli for concentrated maltodextrin samples suggest a highly aggregated, enthalpically linked biopolymer gel. By contrast, the caScinate particles form a ‘pasty’ solid at low temperatures with a high viscous component, which upon moderate heating reverts readily into an entropically driven liquid body. Mixing of the polymers results in a composite system whose phase inversion from a maltodextrin continuous network with discontinuous protein inclusions to a caScinate dispersion suspending the polysaccharide particles is determined by the weight ratio of the two components in the blend. The overall strength of the composite has been related to the mechanical functions of the individual components, and the idea of kinetically trapped mixed gels has been put forward to rationalize the solvent partition between the two constituent phases. Results were used to advance the conclusions reached from work on other mixed biopolymer systems carried out in this laboratory.     

Analysis of a 26 756 bp segment from the left arm of yeast chromosome IV

The nucleotide sequence of a 26·7 kb DNA segment from the left arm of Saccharomyces cerevisiae chromosome IV is presented. An analysis of this segment revealed 11 open reading frames (ORFs) longer than 300 bp and one split gene. These ORFs include the genes encoding the large subunit of RNA polymerase II, the biotin apo-protein ligase, an ADP-ribosylation factor (ARF 2), the ‘L35’-ribosomal protein, a rho GDP dissociation factor, and the sequence encoding the protein phosphatase 2A. Further sequence analysis revealed a short ORF encoding the ribosomal protein YL41B, an intron in a 5′ untranslated region and an extended homology with another cosmid (X83276) located on the same chromosome. The potential biological relevance of these findings is discussed. The sequence was submitted to the EMBL database under Accession Number X96876.     

Genetically Programmed Regioselective Immobilization of Enzymes in Biosilica Microparticles

Diatoms are single‐celled microalgae that produce a large variety of hierarchically porous, silica‐based microparticles as cell wall material. The presence of genetically encoded silica nanopatterns endows the biosilica with favorable properties for a wide range of applications including catalysis, chemical sensing, photonics, and drug delivery. Enhancing the performance of diatom biosilica requires i) a better understanding of the structure–property relationship in this material, and ii) methods that enable the manipulation of the biosilica structure and properties in a targeted manner. Here, genetic engineering of the diatom Thalassiosira pseudonana is employed to immobilize enzymes (glucose oxidase and horseradish peroxidase) into structurally distinct regions of the biosilica, which are termed valves and girdle bands. Remarkably, glucose oxidase in girdle bands exhibits >3‐fold higher catalytic activities compared to its location in valves. It is demonstrated through enzyme accessibility studies, protein engineering, and genetic engineering of biosilica morphology that the divergent enzyme activities are caused by the differences in the inherent silica nanopatterns of valves and girdle bands. This work highlights the importance of silica nanoscale architecture for the activity of immobilized enzymes and provides unprecedented tools for the biotechnological production of silica microparticles with tailored catalytic activities and anisotropic functionalities.     

适度集成有助于汽车功率驱动系统设计

汽车电子系统设计人员在选择MOSFET器件时以前只有两种选择:没有任何保护措施的“简单”PowerMOS或具有完全保护的器件,后者在环境条件超出规定范围时会自动关闭,然而带有额外逻辑和保护电路的完全保护器件成本较高。因此,有些供应商开发了一种介于两者之间的适度集成的新型器件,在单芯片中结合了TrenchMOS技术以及温度和电流传感元件。其优点是不需要昂贵的智能功率器件即可为系统提供保护并节约空间。