Layout design of manufacturable quantum-dot cellular automata

Quantum-dot cellular automaton (QCA) is an emergent technology that is not hindered by quantum effects that limit the scaling of CMOS technology, but instead employs them to perform computation. However, this brings its own impediments, such as the influence of the thermodynamic effects. Beside that, QCA has to be coupled with CMOS circuitry of different size features to enable clocking. We discussed all these facts and devised a floorplan which would facilitate manufacturability. Based on it we developed the process of QCA layout design and defined the design rules that must be considered in order to ensure correct operation. These instructions enable the automatization of designing a QCA circuit layout.     

Reconfigurable digital controller for a buck converter based on FPGA

This paper presents a complete digitally controlled dc–dc buck converter performed by FPGA circuitry. All tasks, analog to digital conversion, control algorithm and pulse width modulation, were implemented in the FPGA. This approach enables high-speed dynamic response and programmability by the controller, without external passive components. In addition, the controller’s structure can be easily changed without external components. The applied algorithm enables a switching frequency of 100 kHz.     

Measurements of electrochemical noise on the passive layer of differently heat treated stainless steels

The passivation current fluctuations have been studied for differently heat treated steels X 20 Cr 13, after 20 h of passivation in 0.2 M H₂SO₄ at constant potentials + 0.20 V, + 0.40 V and + 0.60 V vs. SCE, respectively. Signals of the alternating passivation current have been monitored on the oscilloscope and transformed into a frequency domain by FFT. PSD (Power Spectral Density) values were calculated and represented in the dependence of frequency. These curves (PSD vs. frequency) change with heat treatment, passivation potential and the quality of the passive layers on the steel: ace. to stability and ability of self-repairing.     

Pentadecapeptide BPC 157 positively affects both non-steroidal anti-inflammatory agent-induced gastrointestinal lesions and adjuvant arthritis in rats

Besides a superior protection of the pentadecapeptide BPC 157 (an essential fragment of an organoprotective gastric juice peptide BPC) against different gastrointestinal and liver lesions, an acute anti-inflammatory and analgetic activity was also noted. Consequently, its effect on chronic inflammation lesions, such as adjuvant arthritis, and non-steroidal anti-inflammatory agents (NSAIAs)-induced gastrointestinal lesions was simultaneously studied in rats. In gastrointestinal lesions (indomethacin (30 mg/kg s.c.), aspirin (400 mg/kg i.g.) and diclofenac (125 mg/kg i.p.) studies, BPC 157 (10 micrograms or 10 ng/kg i.p.) was regularly given simultaneously and/or 1 h prior to drug application (indomethacin). In the adjuvant arthritis (tail-application of 0.2 mL of Freund's adjuvant) studies (14 days, 30 days, 1 year) BPC 157 (10 micrograms or 10 ng/kg i.p.), it was given as a single application (at 1 h either before or following the application of Freund's adjuvant) or in a once daily regimen (0-14th day, 14-30th day, 14th day-1 year). Given with the investigated NSAIAs, BPC 157 consistently reduced the otherwise prominent lesions in the stomach of the control rats, as well as the lesions in the small intestine in the indomethacin groups. In the adjuvant arthritis studies, the lesion's development seems to be considerably reduced after single pentadecapeptide medication, and even more attenuated in rats daily treated with BPC 157. As a therapy of already established adjuvant arthritis, its salutary effect consistently appeared already after 2 weeks of medication and it could be clearly seen also after 1 year of application. Taking together all these results, the data likely point to a special anti-inflammatory and mucosal integrity protective effect.     

Coherent phonon anisotropy in aligned single-walled carbon nanotubes

By time-resolved reflectivity measurements with sub-10 fs laser pulses at 395 nm, the coherent phonons of aligned bundles of single-walled carbon nanotubes are observed for various polarization directions of the pump and probe pulses. In the isotropic reflectivity measurement, we observe the radial breathing modes, G, and even D modes, while in the anisotropic reflectivity mode, only the G mode appears. A complex polarization dependence of the G band phonon amplitude in the isotropic reflectivity is explained by the superposition of G band phonons with different symmetries.     

Femtosecond microscopy of surface plasmon polariton wave packet evolution at the silver/vacuum interface

A movie of the dispersive and dissipative propagation of surface plasmon polariton (SPP) wave packets at a silver/vacuum interface is recorded by the interferometric time-resolved photoemission electron microscopy with 60 nm spatial resolution and 330 as frame interval. The evolution of SPP wave packets is imaged through a two-path interference created by a pair of 10 fs phase correlated pump-probe light pulses at 400 nm. The wave packet evolution is simulated using the complex dielectric function of silver.     

The electronic properties of superatom states of hollow molecules

Electronic and optical properties of molecules and molecular solids are traditionally considered from the perspective of the frontier orbitals and their intermolecular interactions. How molecules condense into crystalline solids, however, is mainly attributed to the long-range polarization interaction. In this Account, we show that long-range polarization also introduces a distinctive set of diffuse molecular electronic states, which in quantum structures or solids can combine into nearly-free-electron (NFE) bands. These NFE properties, which are usually associated with good metals, are vividly evident in sp(2) hybridized carbon materials, specifically graphene and its derivatives. The polarization interaction is primarily manifested in the screening of an external charge at a solid/vacuum interface. It is responsible for the universal image potential and the associated unoccupied image potential (IP) states, which are observed even at the He liquid/vacuum interface. The molecular electronic properties that we describe are derived from the IP states of graphene, which float above and below the molecular plane and undergo free motion parallel to it. Rolling or wrapping a graphene sheet into a nanotube or a fullerene transforms the IP states into diffuse atom-like orbitals that are bound primarily to hollow molecular cores, rather than the component atoms. Therefore, we named them the superatom molecular orbitals (SAMOs). Like the excitonic states of semiconductor nanostructures or the plasmonic resonances of metallic nanoparticles, SAMOs of fullerene molecules, separated by their van der Waals distance, can combine to form diatomic molecule-like orbitals of C(60) dimers. For larger aggregates, they form NFE bands of superatomic quantum structures and solids. The overlap of the diffuse SAMO wavefunctions in van der Waals solids provides a different paradigm for band formation than the valence or conduction bands formed by interaction of the more tightly bound, directional highest occupied molecular orbitals (HOMOs) or the lowest unoccupied molecular orbitals (LUMOs). Therefore, SAMO wavefunctions provide insights into the design of molecular materials with potentially superior properties for electronics. Physicists and chemists have thought of fullerenes as atom-like building blocks of electronic materials, and superatom properties have been attributed to other elemental gas-phase clusters based on their size-dependent electronic structure and reactivity. Only in the case of fullerenes, however, do the superatom properties survive as delocalized electronic bands even in the condensed phase. We emphasize, however, that the superatom states and their bands are usually unoccupied and therefore do not contribute to intermolecular bonding. Instead, their significance lies in the electronic properties they confer when electrons are introduced, such as when they are excited optically or probed by the atomically sharp tip of a scanning tunneling microscope. We describe the IP states of graphene as the primary manifestation of the universal polarization response of a molecular sheet and how these states in turn define the NFE properties of materials derived from graphene, such as graphite, fullerenes, and nanotubes. Through low-temperature scanning tunneling microscopy (LT-STM), time-resolved two-photon photoemission spectroscopy (TR-2PP), and density functional theory (DFT), we describe the real and reciprocal space electronic properties of SAMOs for single C(60) molecules and their self-assembled 1D and 2D quantum structures on single-crystal metal surfaces.     

A Two‐Sided Cumulative Sum Chart for First‐Order Integer‐Valued Autoregressive Processes of Poisson Counts

Count data processes are often encountered in manufacturing and service industries. To describe the autocorrelation structure of such processes, a Poisson integer‐valued autoregressive model of order 1, namely, Poisson INAR(1) model, might be used. In this study, we propose a two‐sided cumulative sum control chart for monitoring Poisson INAR(1) processes with the aim of detecting changes in the process mean in both positive and negative directions. A trivariate Markov chain approach is developed for exact evaluation of the ARL performance of the chart in addition to a computationally efficient approximation based on bivariate Markov chains. The design of the chart for an ARL‐unbiased performance and the analyses of the out‐of‐control performances are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparison of alternative approaches of single point incremental forming processes

Incremental sheet metal forming is becoming an attractive technology for fast prototyping and small batch production of sheet metal parts. The majority of investigations are focused on the use of a rigid tool to incrementally form the sheet metal into a final shape. An interesting alternative is to substitute the rigid tool with a high velocity water jet (WJ). The comparison between using a rigid tool and a WJ shows that each method has its advantages and disadvantages. This investigation is aimed to identify the most influential parameters affecting the forming process through experimental comparison of the two observed methods. Technological windows based on non-dimensional values and relevant process parameters like force on the rigid tool and water pressure were defined.