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Sample records for analog electronics based

  1. Problems and Projects Based Approach For Analog Electronic Circuits' Course

    Directory of Open Access Journals (Sweden)

    Mustapha Rafaf

    2009-04-01

    Full Text Available New educational methods and approaches are recently introduced and implemented at several North American and European universities using Problems and Projects Based Approach (PPBA. The PPBA employs a teaching technique based mostly on competences/skills rather than only on knowledge. This method has been implemented and proven by several pedagogical instructors and authors at several educational institutions. This approach is used at different disciplines such as medicine, biology, engineering and many others. It has the advantage to improve the student's skills and the knowledge retention rate, and reflects the 21st century industrial/company needs and demands. Before implementing this approach to a course, a good resources preparation and planning is needed upfront by the responsible or instructor of the course to achieve the course and students related objectives. This paper presents the preparation, the generated documentation and the implementation of a pilot project utilizing PPBA education for a second year undergraduate electronic course over a complete semester, and for two different class groups (morning and evening groups. The outcome of this project (achieved goals, observed difficulties and lessons learned is presented based on different tools such as students 'in class' communication and feedback, different course evaluation forms and the professor/instructor feedback. Resources, challenges, difficulties and recommendations are also assessed and presented. The impact, the effect and the results (during and at the end of the academic fall session of the PPBA on students and instructor are discussed, validated, managed and communicated to help other instructor in taking appropriate approach decisions with respect to this new educational approach compared to the classical one.

  2. Mixing Problem Based Learning and Conventional Teaching Methods in an Analog Electronics Course

    Science.gov (United States)

    Podges, J. M.; Kommers, P. A. M.; Winnips, K.; van Joolingen, W. R.

    2014-01-01

    This study, undertaken at the Walter Sisulu University of Technology (WSU) in South Africa, describes how problem-based learning (PBL) affects the first year 'analog electronics course', when PBL and the lecturing mode is compared. Problems were designed to match real-life situations. Data between the experimental group and the control group that…

  3. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew

    2001-01-01

    Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

  4. An analog electronic cochlea

    OpenAIRE

    Lyon, Richard F.; Mead, Carver

    1988-01-01

    An engineered system that hears, such as a speech recognizer, can be designed by modeling the cochlea, or inner ear, and higher levels of the auditory nervous system. To be useful in such a system, a model of the cochlea should incorporate a variety of known effects, such as an asymmetric low-pass/bandpass response at each output channel, a short ringing time, and active adaptation to a wide range of input signal levels. An analog electronic cochlea has been built in CMOS VLSI technolog...

  5. Practical analog electronics for technicians

    CERN Document Server

    Kimber, W A

    2013-01-01

    'Practical Analog Electronics for Technicians' not only provides an accessible introduction to electronics, but also supplies all the problems and practical activities needed to gain hands-on knowledge and experience. This emphasis on practice is surprisingly unusual in electronics texts, and has already gained Will Kimber popularity through the companion volume, 'Practical Digital Electronics for Technicians'. Written to cover the Advanced GNVQ optional unit in electronics, this book is also ideal for BTEC National, A-level electronics and City & Guilds courses. Together with 'Practical Digit

  6. Analog electronics for radiation detection

    CERN Document Server

    2016-01-01

    Analog Electronics for Radiation Detection showcases the latest advances in readout electronics for particle, or radiation, detectors. Featuring chapters written by international experts in their respective fields, this authoritative text: Defines the main design parameters of front-end circuitry developed in microelectronics technologies Explains the basis for the use of complementary metal oxide semiconductor (CMOS) image sensors for the detection of charged particles and other non-consumer applications Delivers an in-depth review of analog-to-digital converters (ADCs), evaluating the pros and cons of ADCs integrated at the pixel, column, and per-chip levels Describes incremental sigma delta ADCs, time-to-digital converter (TDC) architectures, and digital pulse-processing techniques complementary to analog processing Examines the fundamental parameters and front-end types associated with silicon photomultipliers used for single visible-light photon detection Discusses pixel sensors ...

  7. An Analog Computer for Electronic Engineering Education

    Science.gov (United States)

    Fitch, A. L.; Iu, H. H. C.; Lu, D. D. C.

    2011-01-01

    This paper describes a compact analog computer and proposes its use in electronic engineering teaching laboratories to develop student understanding of applications in analog electronics, electronic components, engineering mathematics, control engineering, safe laboratory and workshop practices, circuit construction, testing, and maintenance. The…

  8. Analog and mixed-signal electronics

    CERN Document Server

    Stephan, Karl

    2015-01-01

    A practical guide to analog and mixed-signal electronics, with an emphasis on design problems and applications This book provides an in-depth coverage of essential analog and mixed-signal topics such as power amplifiers, active filters, noise and dynamic range, analog-to-digital and digital-to-analog conversion techniques, phase-locked loops, and switching power supplies. Readers will learn the basics of linear systems, types of nonlinearities and their effects, op-amp circuits, the high-gain analog filter-amplifier, and signal generation. The author uses system design examples to motivate

  9. Low power analog front-end electronics in deep submicrometer CMOS technology based on gain enhancement techniques

    International Nuclear Information System (INIS)

    This paper evaluates the design of front-end electronics in modern technologies to be used in a new generation of heavy ion detectors—HYDE (FAIR, Germany)—proposing novel architectures to achieve high gain in a low voltage environment. As conventional topologies of operational amplifiers in modern CMOS processes show limitations in terms of gain, novel approaches must be raised. The work addresses the design using transistors with channel length of no more than double the feature size and a supply voltage as low as 1.2 V. A front-end system has been fabricated in a 90 nm process including gain boosting techniques based on regulated cascode circuits. The analog channel has been optimized to match a detector capacitance of 5 pF and exhibits a good performance in terms of gain, speed, linearity and power consumption

  10. Analogy-Based Expectation Equilibrium

    OpenAIRE

    Jehiel, P

    2001-01-01

    It is assumed that players bundle nodes in which other players must move into analogy classes, and players only have expectations about the average behavior in every class. A solution concept is proposed for multi-stage games with perfect information: at every node players choose best-responses to their analogy-based expectations, and expectations are correct on average over those various nodes pooled together into the same analogy classes. The approach is applied to a variety of games. It is...

  11. Electronic devices for analog signal processing

    CERN Document Server

    Rybin, Yu K

    2012-01-01

    Electronic Devices for Analog Signal Processing is intended for engineers and post graduates and considers electronic devices applied to process analog signals in instrument making, automation, measurements, and other branches of technology. They perform various transformations of electrical signals: scaling, integration, logarithming, etc. The need in their deeper study is caused, on the one hand, by the extension of the forms of the input signal and increasing accuracy and performance of such devices, and on the other hand, new devices constantly emerge and are already widely used in practice, but no information about them are written in books on electronics. The basic approach of presenting the material in Electronic Devices for Analog Signal Processing can be formulated as follows: the study with help from self-education. While divided into seven chapters, each chapter contains theoretical material, examples of practical problems, questions and tests. The most difficult questions are marked by a diamon...

  12. Analog Electronic Filters Theory, Design and Synthesis

    CERN Document Server

    Dimopoulos, Hercules G

    2012-01-01

    Filters are essential subsystems in a huge variety of electronic systems. Filter applications are innumerable; they are used for noise reduction, demodulation, signal detection, multiplexing, sampling, sound and speech processing, transmission line equalization and image processing, to name just a few. In practice, no electronic system can exist without filters. They can be found in everything from power supplies to mobile phones and hard disk drives and from loudspeakers and MP3 players to home cinema systems and broadband Internet connections. This textbook introduces basic concepts and methods and the associated mathematical and computational tools employed in electronic filter theory, synthesis and design.  This book can be used as an integral part of undergraduate courses on analog electronic filters. Includes numerous, solved examples, applied examples and exercises for each chapter. Includes detailed coverage of active and passive filters in an independent but correlated manner. Emphasizes real filter...

  13. BOOK REVIEW: An Analog Electronics Companion

    Science.gov (United States)

    Hamilton, Scott

    2003-09-01

    The expression 'Analog electronics' here means the sum of a vast quantity of scientific and technical knowledge and topics. By the same token, the electronic analogue and circuit designer should also have a vast cultural and scientific know-how. The aim of this book is to be a guide for neophytes as well as a useful 'travelling companion' for the mature designer confronted with such a vast world. In my opinion it successfully meets these intentions. The subjects are treated in a concise, clear and self-contained fashion, always helped by a broad exhaustive bibliography, and cover all the necessary aspects for electronic design, such as: the essential elements of mathematical analysis, trigonometry and logarithms to reach Fourier and Laplace transforms and differential equations; physics phenomena and laws from electrostatics and electrodynamics up to Maxwell equations and electronic noise; the fundamental elements of electronic circuit theory and their methods of analysis up to the theory of feedback and control systems; an analysis of the electrical characteristics of the main passive and active electronic components. The above mentioned points take up about half of the text. The remaining topics deal with circuit applications often faced by the electronic designer. In the second part, circuit analysis is treated analytically as well as by the use of CAD, and Pspice software is provided on a CD which illustrates examples. The list of topics treated is long and ranges from operational amplifier circuits to rectifier circuits as well as current feedback amplifiers and high frequency transformers. The book closes by mentioning chaos theory. Daniele Marioli

  14. Foucault's pendulum, a classical analog for the electron spin state

    Science.gov (United States)

    Linck, Rebecca A.

    Spin has long been regarded as a fundamentally quantum phenomena that is incapable of being described classically. To bridge the gap and show that aspects of spin's quantum nature can be described classically, this work uses a classical Lagrangian based on the coupled oscillations of Foucault's pendulum as an analog for the electron spin state in an external magnetic field. With this analog it is possible to demonstrate that Foucault's pendulum not only serves as a basis for explaining geometric phase, but is also a basis for reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured electron spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  15. Ultra-energy-efficient analog-to-digital converters based on single-electron transistor/CMOS hybrid technology for biomedical applications

    International Nuclear Information System (INIS)

    Ultra-energy-efficient analog-to-digital converters (ADCs) based on single-electron transistor (SET)/complementary metal-oxide-semiconductor (CMOS) hybrid technology are proposed as a solution to sense and process biomedical signals. Our results show the energy efficiency of 0.82 pJ/state, which is lower than that in previously reported energy-efficient ADCs. The performance and dissipated power of proposed ADCs are estimated and compared with those of CMOS ADCs by using Lee's SPICE model including non-ideal effects of the experimental data. While the proposed ADC shows an operating power lower by two orders of magnitude than that of the CMOS flash-type ADC, the number of required transistors is about 10% of that in the CMOS flash-type ADC. The peak-to-valley current ratio in Coulomb oscillation of SETs used in the circuit implementation has the range of 1.15–1.5, which is consistent with the experimental result of top-down approached Si-based SETs at T = 77–100 K. From the perspective of the immunity to the gate capacitance Ccg mismatch and the background charge Q0 noise, it is shown that the criteria of SET/CMOS hybrid ADCs are ΔCcg ≤ 0.02 × Ccg (with Ccg = 0.24 aF) and ΔQ0 ≤ 0.23q, respectively

  16. Acoustic analog of a free-electron laser

    International Nuclear Information System (INIS)

    As well known, at the present time there are many types of laser the operation of which is based on the stimulated emission of light by an active medium. Lasers are generators of coherent electromagnetic waves in the range from ultraviolet to submillimeters. But acoustic analogs of such devices have not been created up to now in spite of the progress in laser technology. Meanwhile, an acoustic laser could have a lot of interesting applications. Recently a theoretical scheme for an acoustic laser was proposed by the present author. A liquid dielectric with dispersed particles was considered as an active medium. The pumping was created by an oscillating electric field deforming dispersed particle volumes. Different types of oils or distilled water can serve as a liquid dielectric with gas bubbles as dispersed particles. Gas bubbles in water can be created by an electrolysis. The phase bunching of the initially incoherent emitters (gas bubbles) was realized by acoustic radiation forces. This scheme is an analog of the free-electron laser (FEL). It was shown that two types of losses must be overcome for the beginning of a generation. The first type results from the energy dissipation in the active medium and the second one is caused by radiation losses at the boundaries of the resonator. The purposes of this report are: (1) to discuss the analogies between the acoustic laser and FEL; (2) to propose an effective scheme of an acoustic laser with a mechanical pumping (by a piezoelectric emitter of the piston type); (3) to consider the schemes of acoustic lasers with the different types of the resonators (rectangular and cylindrical); (4) to discuss the possibility of the creation of an impact acoustic laser (5) to discuss the experimental works which are planned to be carried out in cooperation with prof. L.A. Crum

  17. Analogies: Explanatory Tools in Web-Based Science Instruction

    Science.gov (United States)

    Glynn, Shawn M.; Taasoobshirazi, Gita; Fowler, Shawn

    2007-01-01

    This article helps designers of Web-based science instruction construct analogies that are as effective as those used in classrooms by exemplary science teachers. First, the authors explain what analogies are, how analogies foster learning, and what form analogies should take. Second, they discuss science teachers' use of analogies. Third, they…

  18. Electronics basic, analog, and digital with PSpice

    CERN Document Server

    Sabah, Nassir H

    2009-01-01

    Preface Foreword: Brief History and Impact of Electronics Convention for Symbols Basic Diode Circuits Overview Learning Objectives Ideal and Practical Diodes Ideal Diode Ideal Si pn Junction Diode Practical Diodes Incremental Diode Resistance Basic Analysis of Diode Circuits Piecewise Linear Approximation Bias Point Small-Signal Model Rectifier Circuits Half-Wave Rectifier Full-Wave Rectifier Smoothing of Output Capacitor-Input Filter Approximate Analysis of Capacitor-Input Filter Zener Voltage Regulator Voltage-Current Characteristic Analysis of Zener Regulator Load regulation and Line Regula

  19. Electronic analogy of Goos-H\\"{a}nchen effect: a review

    OpenAIRE

    Chen, Xi; Lu, Xiao-Jing; Ban, Yue; Li, Chun-Fang

    2013-01-01

    The analogies between optical and electronic Goos-H\\"{a}nchen effects are established based on electron wave optics in semiconductor or graphene-based nanostructures. In this paper, we give a brief overview of the progress achieved so far in the field of electronic Goos-H\\"{a}nchen shifts, and show the relevant optical analogies. In particular, we present several theoretical results on the giant positive and negative Goos-H\\"{a}nchen shifts in various semiconductor or graphen-based nanostruct...

  20. Graphene-on-semiconductor substrates for analog electronics

    Science.gov (United States)

    Lagally, Max G.; Cavallo, Francesca; Rojas-Delgado, Richard

    2016-04-26

    Electrically conductive material structures, analog electronic devices incorporating the structures and methods for making the structures are provided. The structures include a layer of graphene on a semiconductor substrate. The graphene layer and the substrate are separated by an interfacial region that promotes transfer of charge carriers from the surface of the substrate to the graphene.

  1. Fuzzy classifier for fault diagnosis in analog electronic circuits.

    Science.gov (United States)

    Kumar, Ashwani; Singh, A P

    2013-11-01

    Many studies have presented different approaches for the fault diagnosis with fault models having ± 50% variation in the component values in analog electronic circuits. There is still a need of the approaches which provide the fault diagnosis with the variation in the component value below ± 50%. A new single and multiple fault diagnosis technique for soft faults in analog electronic circuit using fuzzy classifier has been proposed in this paper. This technique uses the simulation before test (SBT) approach by analyzing the frequency response of the analog circuit under faulty and fault free conditions. Three signature parameters peak gain, frequency and phase associated with peak gain, of the frequency response of the analog circuit are observed and extracted such that they give unique values for faulty and fault free configuration of the circuit. The single and double fault models with the component variations from ± 10% to ± 50% are considered. The fuzzy classifier along the classification of faults gives the estimated component value under faulty and faultfree conditions. The proposed method is validated using simulated data and the real time data for a benchmark analog circuit. The comparative analysis is also presented for both the validations. PMID:23849881

  2. Immunophotoelectron microscopy: The electron optical analog of immunofluorescence microscopy

    OpenAIRE

    1985-01-01

    The electron optical analog of immunofluorescence microscopy combines three developments: (i) photo-electron microscopy to produce a high-resolution image of exposed components of the cell, (ii) site-specific antibodies, and (iii) photoemissive markers coupled to the antibodies to make the distribution of sites visible. This approach, in theory, provides a way to extend the useful immunofluorescence microscopy technique to problems requiring much higher resolution. The resolution limit of flu...

  3. Foucault's Pendulum, Analog for an Electron Spin State

    Science.gov (United States)

    Linck, Rebecca

    2012-11-01

    The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  4. A neurocomputer based on an analog-digital hybrid architecture

    Science.gov (United States)

    Moopenn, A.; Thakoor, A. P.; Duong, T.; Khanna, S. K.

    1987-01-01

    A novel analog-digital hybrid architecture based on the utilization of high density digital random access memories for the storage of the synaptic weights of a neural network, and high speed analog hardware to perform neural computation is described. An electronic neurocomputer based on such an architecture is ideally suited for investigating the dynamics, associative recall properties, and computational capabilities of neural networks and provides significant speed improvement in comparison to conventional software based neural network simulations. As a demonstration of the feasibility of the hybrid architectural concept, a prototype breadboard hybrid neurocomputer system with 32 neurons has been designed and fabricated with off-the-shelf hardware components. The performance of the breadboard system has been tested for variety of applications including associative memory and combinatorial problem solving such as Graph Coloring, and is discussed in this paper.

  5. Analog computing using graphene-based metalines.

    Science.gov (United States)

    AbdollahRamezani, Sajjad; Arik, Kamalodin; Khavasi, Amin; Kavehvash, Zahra

    2015-11-15

    We introduce the new concept of "metalines" for manipulating the amplitude and phase profile of an incident wave locally and independently. Thanks to the highly confined graphene plasmons, a transmit-array of graphene-based metalines is used to realize analog computing on an ultra-compact, integrable, and planar platform. By employing the general concepts of spatial Fourier transformation, a well-designed structure of such meta-transmit-array, combined with graded index (GRIN) lenses, can perform two mathematical operations, i.e., differentiation and integration, with high efficiency. The presented configuration is about 60 times shorter than the recent structure proposed by Silva et al. [Science343, 160 (2014)SCIEAS0036-807510.1126/science.1242818]; moreover, our simulated output responses are in better agreement with the desired analytical results. These findings may lead to remarkable achievements in light-based plasmonic signal processors at nanoscale, instead of their bulky conventional dielectric lens-based counterparts. PMID:26565844

  6. Electronic Circuit Analog of Synthetic Genetic Networks: Revisited

    CERN Document Server

    Hellen, Edward H

    2016-01-01

    Electronic circuits are useful tools for studying potential dynamical behaviors of synthetic genetic networks. The circuit models are complementary to numerical simulations of the networks, especially providing a framework for verification of dynamical behaviors in the presence of intrinsic and extrinsic noise of the electrical systems. Here we present an improved version of our previous design of an electronic analog of genetic networks that includes the 3-gene Repressilator and we show conversions between model parameters and real circuit component values to mimic the numerical results in experiments. Important features of the circuit design include the incorporation of chemical kinetics representing Hill function inhibition, quorum sensing coupling, and additive noise. Especially, we make a circuit design for a systematic change of initial conditions in experiment, which is critically important for studies of dynamical systems' behavior, particularly, when it shows multistability. This improved electronic ...

  7. Analog Signal Correlating Using an Analog-Based Signal Conditioning Front End

    Science.gov (United States)

    Prokop, Norman; Krasowski, Michael

    2013-01-01

    This innovation is capable of correlating two analog signals by using an analog-based signal conditioning front end to hard-limit the analog signals through adaptive thresholding into a binary bit stream, then performing the correlation using a Hamming "similarity" calculator function embedded in a one-bit digital correlator (OBDC). By converting the analog signal into a bit stream, the calculation of the correlation function is simplified, and less hardware resources are needed. This binary representation allows the hardware to move from a DSP where instructions are performed serially, into digital logic where calculations can be performed in parallel, greatly speeding up calculations.

  8. Analysis and application of analog electronic circuits to biomedical instrumentation

    CERN Document Server

    Northrop, Robert B

    2012-01-01

    All chapters include an introduction and chapter summary.Sources and Properties of Biomedical SignalsSources of Endogenous Bioelectric SignalsNerve Action PotentialsMuscle Action PotentialsThe ElectrocardiogramOther BiopotentialsElectrical Properties of BioelectrodesExogenous Bioelectric SignalsProperties and Models of Semiconductor Devices Used in Analog Electronic Systemspn Junction DiodesMidfrequency Models for BJT BehaviorMidfrequency Models for Field-Effect TransistorsHigh-Frequency Models for Transistors and Simple Transistor AmplifiersPhotons, Photodiodes, Photoconductors, LEDs, and Las

  9. The Discourse on Printed and Electronic Books: Analogies, Oppositions, and Perspectives

    Science.gov (United States)

    Velagic, Zoran

    2014-01-01

    Introduction: The point of departure for this paper is the twofold analogy (analogy of content, analogy of medium) between printed and electronic books, the aim being to draw attention to the usual perception of their capacities and relationships, to provide a rather detailed analysis of the outcome and sustainability of such analogies and…

  10. Digital and Analog Electronics for an autonomous, deep-sea, Gamma Ray Burst Neutrino prototype detector

    Directory of Open Access Journals (Sweden)

    Manolopoulos K.

    2016-01-01

    Full Text Available GRBNeT is a Gamma Ray Burst Neutrino Telescope made of autonomously operated arrays of deep-sea light detectors, anchored to the sea-bed without any cabled connection to the shore. This paper presents the digital and analog electronics that we have designed and developed for the GRBNeT prototype. We describe the requirements for these electronics and present their design and functionality. We present low-power analog electronics for the PMTs utilized in the GRBNeT prototype and the FPGA based digital system for data selection and storage. We conclude with preliminary performance measurements of the electronics systems for the GRBNeT prototype.

  11. Analog front-end prototype electronics for the LHAASO WCDA

    Science.gov (United States)

    Cong, Ma; Lei, Zhao; Yu-Xiang, Guo; Jian-Feng, Liu; Shu-Bin, Liu; Qi, An

    2016-01-01

    In the readout electronics of the Water Cerenkov Detector Array (WCDA) in the Large High Altitude Air Shower Observatory (LHAASO) experiment, both high-resolution charge and time measurement are required over a dynamic range from 1 photoelectron (P.E.) to 4000 P.E. The Analog Front-end (AFE) circuit is one of the crucial parts in the readout electronics. We designed and optimized a prototype of the AFE through parameter calculation and circuit simulation, and conducted initial electronics tests on this prototype to evaluate its performance. Test results indicate that the charge resolution is better than 1%@4000 P.E. and remains better than 10%@1 P.E., and the time resolution is better than 0.5 ns RMS, which is better than the application requirements. Supported by Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), National Natural Science Foundation of China (11175174) and CAS Center for Excellence in Particle Physics (CCEPP)

  12. Reconfiguration of Analog Electronics for Extreme Environments: Problem or Solution?

    Science.gov (United States)

    Stoica, Adrian; Zebulum, Ricardo; Keymeulen, Didier; Guo, Xin

    2005-01-01

    This paper argues in favor of adaptive reconfiguration as a technique to expand the operational envelope of analog electronics for extreme environments (EE). In addition to hardening-by-process and hardening-by-design, "hardening-by-reconfiguration", when applicable, could be used to mitigate drifts, degradation, or damage on electronic devices (chips) in EE, by using re-configurable devices and an adaptive self-reconfiguration of their circuit topology. Conventional circuit design exploits device characteristics within a certain temperature/radiation range; when that is exceeded, the circuit function degrades. On a reconfigurable device, although component parameters change in EE, as long as devices still operate, albeit degraded, a new circuit design, suitable for new parameter values, may be mapped into the reconfigurable structure to recover the initial circuit function. Partly degraded resources are still used, while completely damaged resources are bypassed. Designs suitable for various environmental conditions can be determined prior to operation or can be determined in-situ, by adaptive reconfiguration algorithms running on built-in digital controllers. Laboratory demonstrations of this technique were performed by JPL in several independent experiments in which bulk CMOS reconfigurable devices were exposed to, and degraded by, low temperatures (approx. 196 C), high temperatures (approx.300 C) or radiation (300kRad TID), and then recovered by adaptive reconfiguration using evolutionary search algorithms. Taking this technology from Technology Readiness Level (TRL) 3 to TRL 5 is the target of a current NASA project.

  13. Asymmetric bilayer graphene nanoribbon MOSFETs for analog and digital electronics

    Science.gov (United States)

    Dinarvand, A.; Ahmadi, V.; Darvish, Gh.

    2016-05-01

    In this paper, a new structure was proposed for bilayer graphene nanoribbon field-effect transistor (BGNFET) mainly to enhance the electrical characteristics in analog and digital applications. The proposed device uses two metallic gates on the top and bottom of a bilayer graphene nanoribbon, which is surrounded by SiO2 and connected to heavily doped source/drain contacts. Electrical properties of the proposed device were explored using fully self-consistent solution of Poisson and Schrödinger equations based on the nonequilibrium Green's function (NEGF) formalism. Significant improvements in the electrical behavior was seen in the simulation results for gates asymmetrically biased. The comparison with graphene nanoribbon FET showed that the proposed structure benefited from higher intrinsic voltage gain and cut-off frequency and improved switching characteristics such as delay and Ion/Ioff ratio.

  14. Impact of Analog IC Impairments in SiPM Interface Electronics.

    Science.gov (United States)

    Dey, Samrat; Lewellen, Thomas K; Miyaoka, Robert S; Rudell, Jacques C

    2012-01-01

    The recent realization of Silicon Photomultiplier (SiPM) devices as solid-state detectors for Positron Emission Tomography holds the promise of improving image resolution, integrating a significant portion of the interface electronics, and potentially lowering the power consumption. Our lab has previously reported on novel board-level readout electronics for an 8×8 silicon photomultiplier (SiPM) array featuring row/column summation technique to reduce the hardware requirements for signal processing and is currently working on taking the next step by implementing a monolithic CMOS chip which is based on the row-column architecture. To date, relatively little modeling has been done to understand the impact of analog non-idealities associated with the front-end electronics, on SiPM-based PET systems. This paper focuses on various analog impairments associated with PET scanner readout electronics. Matlab was used as a simulation platform to model the noise, linearity and signal bandwidth of the frontend electronics with the measured SiPM pulses as the input. PMID:24817765

  15. Analogs of Basic Electronic Circuit Elements in a Free-Space Atom Chip

    Science.gov (United States)

    Lee, Jeffrey G.; McIlvain, Brian J.; Lobb, C. J.; Hill, W. T., III

    2013-01-01

    Using a thermal sample of laser-cooled rubidium atoms, we have constructed a neutral-atom circuit analogous to an electronic capacitor discharged through a resistor. The atoms are confined using what we call a free-space atom chip, an optical dipole trap created using a generalized phase-contrast imaging technique. We have also calculated theoretical values for the capacitance and resistance, which agree with our experiments, as well as theoretical value for an atomic analog of electrical inductance. We show that atomic capacitance is analogous to the quantum capacitance, the atomic resistance is analogous to the ballistic, or Sharvin resistance, and the atomic inductance is analogous to kinetic inductance.

  16. Proposal, development and test of an analog front-end electronic board for Nemo telescope

    CERN Document Server

    Caponetto, L; Gandolfi, E; Giorgi, F M; Lo Presti, D; Randazzo, N

    2007-01-01

    The NEMO collaboration is involved in the R&D of the main technologies for the project of a km3 scale underwater neutrino telescope. The proposed detector is made up of thousands of Optical Modules (hereafter OM), spread over the entire volume for Cˇ erenkov light detection. Each OMis equipped with a photo multiplier tube (PMT) and an electronic circuit for data acquisition and transmission (DAQ-Board). This work points out the possible benefits of a hybrid solution based on an analog ASIC (Application Specific Integrated Circuit) employed for the analog signal acquisition and an FPGA (Field Programmable Gate Array), a digital programmable IC (Integrated Circuit) which performs the data acquisition and the data transmission.

  17. Analog circuit design optimization based on evolutionary algorithms

    OpenAIRE

    Barari, Mansour; Karimi, Hamid Reza; Razaghian, Farhad

    2014-01-01

    This paper investigates an evolutionary-based designing system for automated sizing of analog integrated circuits (ICs). Two evolutionary algorithms, genetic algorithm and PSO (Parswal particle swarm optimization) algorithm, are proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through specific electrical simulation, to the optimization system in the MATLAB environmen...

  18. Analog Circuit Design Optimization Based on Evolutionary Algorithms

    OpenAIRE

    Mansour Barari; Hamid Reza Karimi; Farhad Razaghian

    2014-01-01

    This paper investigates an evolutionary-based designing system for automated sizing of analog integrated circuits (ICs). Two evolutionary algorithms, genetic algorithm and PSO (Parswal particle swarm optimization) algorithm, are proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through specific electrical simulation, to the optimization system in the MATLAB environmen...

  19. An analog bipolar-JFET master slice array for front-end electronics design

    International Nuclear Information System (INIS)

    An analog bipolar-JFET Master Slice Array (MSA) has been designed for implementation of ICs used in nuclear physics front-end electronics. The universal conception of MSAs active and passive elements provides great functional complexity to ICs in using them. The quality of active element parameters, number and values of available resistors and capacitors made it possible to integrate a four channel amplifier-shaper-discriminator with a base line restorer into the MSA die with dimensions 2.7 mmx3.6 mm. Eight-channel ICs can be made by connection of two chips by metal wiring on a wafer

  20. Electronic design automation of analog ICs combining gradient models with multi-objective evolutionary algorithms

    CERN Document Server

    Rocha, Frederico AE; Lourenço, Nuno CC; Horta, Nuno CG

    2013-01-01

    This book applies to the scientific area of electronic design automation (EDA) and addresses the automatic sizing of analog integrated circuits (ICs). Particularly, this book presents an approach to enhance a state-of-the-art layout-aware circuit-level optimizer (GENOM-POF), by embedding statistical knowledge from an automatically generated gradient model into the multi-objective multi-constraint optimization kernel based on the NSGA-II algorithm. The results showed allow the designer to explore the different trade-offs of the solution space, both through the achieved device sizes, or the resp

  1. An Implementation of POPBL for Analog Electronics (BEL10203 Course at the Faculty Of Electrical and Electronic Engineering, Uthm

    Directory of Open Access Journals (Sweden)

    Masnani Mohamed

    2012-04-01

    Full Text Available A Project Oriented Problem Based Learning (POPBL has been introduced to the first year students in the Analog Electronics (BEL10203 course at the Faculty of Electrical and Electronic Engineering, UTHM. The aim is to design an electronic circuit using transistors and diodes that can function as electronic appliances with low cost, low power consumption, and has the features of smart and portable. The total of 143 students were divided into groups and assigned to setup an electronic based company that will be manufacturing the electronic product. Each group had to conduct their regular meetings and develop different kind of products with their creativity. The overall evaluation is divided for both lecturer and peer assessment which carried 20% of their course work. The assessment covered 60% of evaluation for the group management, attitude, progress presentation, report writing while another 40% for the functionality and features of their product. As a result, the POPBL session has increased the student’s ability to analyze and design an analog circuit using various kinds of transistors and diodes. They also gained practical understanding on transistor and diode operation. The POPBL not only expanded their experience in using software tools for circuit design and simulation, but also developed greater awareness to conduct professional presentation and technical report. They also learned to work as professional, keen to ethical responsibilities and committed to the group. The analysis conducted has shown that 95% of the students agreed that the problem given helped them understands better the course syllabus and developed a good problem solving skills.

  2. Investigation and Manipulation of Different Analog Behaviors of Memristor as Electronic Synapse for Neuromorphic Applications

    Science.gov (United States)

    Wang, Changhong; He, Wei; Tong, Yi; Zhao, Rong

    2016-03-01

    Low-power and high-density electronic synapse is an important building block of brain-inspired systems. The recent advancement in memristor has provided an opportunity to advance electronic synapse design. However, a guideline on designing and manipulating the memristor’s analog behaviors is still lacking. In this work, we reveal that compliance current (Icomp) of electroforming process played an important role in realizing a stable analog behavior, which is attributed to the generation of conical-type conductive filament. A proper Icomp could result in a large conductance window, good stability, and low voltage analog switching. We further reveal that different pulse conditions can lead to three analog behaviors, where the conductance changes in monotonic increase, plateau after initial jump, and impulse-like shape, respectively. These behaviors could benefit the design of electronic synapse with enriched learning capabilities. This work will provide a useful guideline for designing and manipulating memristor as electronic synapses for brain-inspired systems.

  3. Analog IC techniques for low-voltage low-power electronics

    OpenAIRE

    Serdijn, W. A.; Verhoeven, C.J.M.; Van Roermund, A.H.M.

    1995-01-01

    Analog IC Techniques lor Low-Voltage Low Power Electronics addresses many very important, but recent, techniques which enable electronics to operate at a low supply voltage and consume a minimum amount of power. Apart from investigations at the device, circuit and system levels, the book provides a wealth of practical implementations, many worked out in silicon realizations. The book is intended for both the professional designer of low-voltage low-power analog integrated circuits and the gra...

  4. Investigation and Manipulation of Different Analog Behaviors of Memristor as Electronic Synapse for Neuromorphic Applications

    OpenAIRE

    Changhong Wang; Wei He; Yi Tong; Rong Zhao

    2016-01-01

    Low-power and high-density electronic synapse is an important building block of brain-inspired systems. The recent advancement in memristor has provided an opportunity to advance electronic synapse design. However, a guideline on designing and manipulating the memristor’s analog behaviors is still lacking. In this work, we reveal that compliance current (I comp) of electroforming process played an important role in realizing a stable analog behavior, which is attributed to the generation of c...

  5. Nucleotide analogs based on pentaerythritol — An hypothesis

    Science.gov (United States)

    Schwartz, Alan W.

    1993-06-01

    The synthesis of ribose and ribose-based nucleotides under reasonable prebiotic conditions has not been achieved. Glycerol has been suggested as a structural unit that might have preceded ribose in the evolutionary emergence of RNA. Template-directed oligomerizations of nucleotide analogs based on glycerol, however, have been only partially successful. Recent studies on the effect of ultraviolet irradiation of formaldehyde solutions have shown that the reduced sugar pentaerythritol is formed with great specificity. I argue that pentaerythritol is potentially capable of being converted by simple chemistry into a series of nucleoside analogs related to barbituric acid. These analogs may be able to take part in nucleic acid-like interactions and could therefore be of potential interest as a new class of candidates as RNA precursors.

  6. Analysis and application of analog electronic circuits to biomedical instrumentation

    CERN Document Server

    Northrop, Robert B

    2003-01-01

    This book introduces the basic mathematical tools used to describe noise and its propagation through linear systems and provides a basic description of the improvement of signal-to-noise ratio by signal averaging and linear filtering. The text also demonstrates how op amps are the keystone of modern analog signal conditioning systems design, and illustrates their use in isolation and instrumentation amplifiers, active filters, and numerous biomedical instrumentation systems and subsystems. It examines the properties of the ideal op amp and applies this model to the analysis of various circuits

  7. Analog Group Delay Equalizers Design Based on Evolutionary Algorithm

    Directory of Open Access Journals (Sweden)

    M. Laipert

    2006-04-01

    Full Text Available This paper deals with a design method of the analog all-pass filter designated for equalization of the group delay frequency response of the analog filter. This method is based on usage of evolutionary algorithm, the Differential Evolution algorithm in particular. We are able to design such equalizers to be obtained equal-ripple group delay frequency response in the pass-band of the low-pass filter. The procedure works automatically without an input estimation. The method is presented on solving practical examples.

  8. Analog Circuit Design Optimization Based on Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Mansour Barari

    2014-01-01

    Full Text Available This paper investigates an evolutionary-based designing system for automated sizing of analog integrated circuits (ICs. Two evolutionary algorithms, genetic algorithm and PSO (Parswal particle swarm optimization algorithm, are proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through specific electrical simulation, to the optimization system in the MATLAB environment, for the selected topology. The system has been tested by typical and hard-to-design cases, such as complex analog blocks with stringent design requirements. The results show that the design specifications are closely met. Comparisons with available methods like genetic algorithms show that the proposed algorithm offers important advantages in terms of optimization quality and robustness. Moreover, the algorithm is shown to be efficient.

  9. Investigating student learning in upper-division laboratory courses on analog electronics

    Science.gov (United States)

    Stetzer, Mackenzie

    2015-03-01

    There are many important learning goals associated with upper-division laboratory instruction; however, until recently, relatively little work has focused on assessing the impact of these laboratory-based courses on students. As part of an ongoing, in-depth investigation of student learning in upper-division laboratory courses on analog electronics, we have been examining the extent to which students enrolled in these courses develop a robust and functional understanding of both canonical electronics topics (e.g., diode, transistor, and op-amp circuits) and foundational circuits concepts (e.g., Kirchhoff's laws and voltage division). This focus on conceptual understanding is motivated in part by a large body of research revealing significant student difficulties with simple dc circuits at the introductory level and by expectations that students finish electronics courses with a level of understanding suitable for building common, practical circuits in a real-world environment. Recently, we have extended the scope of our investigation to include more laboratory-focused learning goals such as the development of (1) troubleshooting proficiency and (2) circuit chunking and design abilities. In this talk, I will highlight findings from written questions and interview tasks that have been designed to probe student understanding in sufficient depth to identify conceptual and reasoning difficulties. I will also use specific examples to illustrate the ways in which this research may inform instruction in upper-division laboratory courses on analog electronics. This work has been supported in part by the National Science Foundation under Grant Nos. DUE-1323426, DUE-1022449, DUE-0962805, and DUE-0618185.

  10. Analog IC techniques for low-voltage low-power electronics

    NARCIS (Netherlands)

    Serdijn, W.A.; Verhoeven, C.J.M.; Van Roermund, A.H.M.

    1995-01-01

    Analog IC Techniques lor Low-Voltage Low Power Electronics addresses many very important, but recent, techniques which enable electronics to operate at a low supply voltage and consume a minimum amount of power. Apart from investigations at the device, circuit and system levels, the book provides a

  11. Analogy between gambling and measurement-based work extraction

    Science.gov (United States)

    Vinkler, Dror A.; Permuter, Haim H.; Merhav, Neri

    2016-04-01

    In information theory, one area of interest is gambling, where mutual information characterizes the maximal gain in wealth growth rate due to knowledge of side information; the betting strategy that achieves this maximum is named the Kelly strategy. In the field of physics, it was recently shown that mutual information can characterize the maximal amount of work that can be extracted from a single heat bath using measurement-based control protocols, i.e. using ‘information engines’. However, to the best of our knowledge, no relation between gambling and information engines has been presented before. In this paper, we briefly review the two concepts and then demonstrate an analogy between gambling, where bits are converted into wealth, and information engines, where bits representing measurements are converted into energy. From this analogy follows an extension of gambling to the continuous-valued case, which is shown to be useful for investments in currency exchange rates or in the stock market using options. Moreover, the analogy enables us to use well-known methods and results from one field to solve problems in the other. We present three such cases: maximum work extraction when the probability distributions governing the system and measurements are unknown, work extraction when some energy is lost in each cycle, e.g. due to friction, and an analysis of systems with memory. In all three cases, the analogy enables us to use known results in order to obtain new ones.

  12. Analog electronic model of the lobster pyloric central pattern generator

    International Nuclear Information System (INIS)

    An electronic circuit intended to simulate the nonlinear dynamics of a simplified 3-cell model of the pyloric central pattern generator in California spiny lobster stomato gastric ganglion is presented. The model employs the synaptic phase locked loop (SPLL) concept where the frequency of oscillations of a postsynaptic cell is mainly controlled by the synaptic current which depends on the phase shift between the oscillations. The theoretical study showed that the system has a stable steady state with correct phase shifts between the oscillations and that this regime is stable when the frequency of the pacemaker cell is varied over a wide range. The main bifurcations in the system were studied analytically, in computer simulations, and in experiments with the electronic circuit. The experimental measurements are in good agreement with the expectations of the theoretical model

  13. Phononics: Manipulating heat flow with electronic analogs and beyond

    OpenAIRE

    Li, Nianbei; Ren, Jie; Wang, Lei; Zhang, Gang; Hänggi, Peter; Li, Baowen

    2011-01-01

    The form of energy termed heat that typically derives from lattice vibrations, i.e. the phonons, is usually considered as waste energy and, moreover, deleterious to information processing. However, with this colloquium, we attempt to rebut this common view: By use of tailored models we demonstrate that phonons can be manipulated like electrons and photons can, thus enabling controlled heat transport. Moreover, we explain that phonons can be put to beneficial use to carry and process informati...

  14. Verifying analog circuits based on a digital signature

    OpenAIRE

    Gómez Pau, Álvaro; Sanahuja Moliner, Ricard; Balado Suárez, Luz María; Figueras Pàmies, Joan

    2009-01-01

    Verification of analog circuit specifications is a challenging task requiring expensive test equipment and time consuming procedures. This paper presents a method for low cost parameter verification based on statistical analysis of a digital signature. A CMOS on-chip monitor and sampler circuit generates the digital signature of the CUT. The monitor composes two signals (x(t); y(t)) and divides the X-Y plane with nonlinear boundaries in order to generate a digital code fo...

  15. A DSP-based, analog-to-digital convertor for nuclear radiation spectroscopy

    International Nuclear Information System (INIS)

    A new, digital signal processor (DSP)-based system is under development for analyzing and processing pulses produced by radiation detectors. A DSP-based system will be capable of advanced features for all types of radiation spectroscopy systems (e.g., pulse validation, pulse shape analysis, dynamic threshold determination, and noise reduction) with fewer and simpler electronics for increased reliability, reduced electronic noise, and less expense. A prototype system has been built, and performance parameters are being evaluated. The analysis of a pulse from radiation detectors is currently performed by converting the peak of the detector pulse from analog form to digital form with a peak detection analog-to-digital converter (ADC). To accomplish this, the pulse from the detector is first amplified and shaped. The peak of the pulse is captured and subsequently converted to digital form

  16. Analogical reasoning for reliability analysis based on generic data

    Energy Technology Data Exchange (ETDEWEB)

    Kozin, Igor O

    1996-10-01

    The paper suggests using the systemic concept 'analogy' for the foundation of an approach to analyze system reliability on the basis of generic data, describing the method of structuring the set that defines analogical models, an approach of transition from the analogical model to a reliability model and a way of obtaining reliability intervals of analogous objects.

  17. An FPGA-Based Electronic Cochlea

    OpenAIRE

    M. P. Leong; Jin, Craig T.; Philip H.W. Leong

    2003-01-01

    A module generator which can produce an FPGA-based implementation of an electronic cochlea filter with arbitrary precision is presented. Although hardware implementations of electronic cochlea models have traditionally used analog VLSI as the implementation medium due to their small area, high speed, and low power consumption, FPGA-based implementations offer shorter design times, improved dynamic range, higher accuracy, and a simpler computer interface. The tool presented takes filter coeffi...

  18. Analog VLSI-based modeling of the primate oculomotor system.

    Science.gov (United States)

    Horiuchi, T K; Koch, C

    1999-01-01

    One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real time using similar constraints. Analog very large-scale integrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing and fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built that simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brain stem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, and saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates. PMID:9950732

  19. Documentary Realism, Sampling Theory and Peircean Semiotics: electronic audiovisual signs (analog or digital as indexes of reality

    Directory of Open Access Journals (Sweden)

    Hélio Godoy

    2007-07-01

    Full Text Available This paper addresses Documentary Realism, focusing on thephysical phenomena of transduction that take place in analog and digital audiovisual systems, herein analyzed in the light of the Sampling Theory, within the framework of Shannon and Weaver’s Information Theory. Transduction is a process by which one type of energy is transformed into another, or by which information is transcodified. Within the scope of Documentary Realism, it cannotbe claimed that electronic audiovisual signs, because of their technical digital features lead to a rupture with reality. Rather, the digital documentary, based on electronic digital cinematography, is still an index of reality.

  20. Hamiltonian system for orthotropic plate bending based on analogy theory

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on analogy between plane elasticity and plate bending as well as variational principles of mixed energy, Hamiltonian system is further led to orthotropic plate bending problems in this paper. Thus many effective methods of mathematical physics such as separation of variables and eigenfunction expansion can be employed in orthotropic plate bending problems as they are used in plane elasticity. Analytical solutions of rectangular plate are presented directly, which expands the range of analytical solutions. There is an essential distinction between this method and traditional semi-inverse method. Numerical results of orthotropic plate with two lateral sides fixed are included to demonstrate the effectiveness and accuracy of this method.

  1. Analog circuit test based on a digital signature

    OpenAIRE

    Gómez Pau, Álvaro; Sanahuja Moliner, Ricard; Balado Suárez, Luz María; Figueras Pàmies, Joan

    2010-01-01

    Production verification of analog circuit specifica- tions is a challenging task requiring expensive test equipment and time consuming procedures. This paper presents a method for low cost on-chip parameter verification based on the analysis of a digital signature. A 65 nm CMOS on-chip monitor is proposed and validated in practice. The monitor composes two signals (x(t), y(t)) and divides the X-Y plane with nonlinear boundaries in order to generate a digital code for ever...

  2. Fabrication of Analog Electronics for Serial Readout of Silicon Strip Sensors

    CERN Document Server

    Won, E; Ha, H; Hyun, H J; Kim, H J; Park, H

    2007-01-01

    A set of analog electronics boards for serial readout of silicon strip sensors was fabricated. A commercially available amplifier is mounted on a homemade hybrid board in order to receive analog signals from silicon strip sensors. Also, another homemade circuit board is fabricated in order to translate amplifier control signals into a suitable format and to provide bias voltage to the amplifier as well as to the silicon sensors. We discuss technical details of the fabrication process and performance of the circuit boards we developed.

  3. Analog Optical Computing Based on Dielectric Meta-reflect-array

    CERN Document Server

    Chizari, Ata; Jamali, Mohammad Vahid; Salehi, Jawad A

    2016-01-01

    In this paper, we realize the concept of analog computing using an array of engineered gradient dielectric meta-reflect-array. The proposed configuration consists of individual subwavelength silicon nanobricks in combination with fused silica spacer and silver ground plane realizing a reflection beam with full phase coverage $2\\pi$ degrees as well as amplitude range $0$ to $1$. Spectrally overlapping electric and magnetic dipole resonances, such high-index dielectric metasurfaces can locally and independently manipulate the amplitude and phase of the incident electromagnetic wave. This practically feasible structure overcomes substantial limitations imposed by plasmonic metasurfaces such as absorption losses and low polarization conversion efficiency in the visible range. Using such CMOS-compatible and easily integrable platforms promises highly efficient ultrathin planar wave-based computing systems which circumvent the drawbacks of conventional bulky lens-based signal processors. Based on these key properti...

  4. Soft Fault Diagnosis for Analog Circuits Based on Slope Fault Feature and BP Neural Networks

    Institute of Scientific and Technical Information of China (English)

    HU Mei; WANG Hong; HU Geng; YANG Shiyuan

    2007-01-01

    Fault diagnosis is very important for development and maintenance of safe and reliable electronic circuits and systems. This paper describes an approach of soft fault diagnosis for analog circuits based on slope fault feature and back propagation neural networks (BPNN). The reported approach uses the voltage relation function between two nodes as fault features; and for linear analog circuits, the voltage relation function is a linear function, thus the slope is invariant as fault feature. Therefore, a unified fault feature for both hard fault (open or short fault) and soft fault (parametric fault) is extracted. Unlike other NN-based diagnosis methods which utilize node voltages or frequency response as fault features, the reported BPNN is trained by the extracted feature vectors, the slope features are calculated by just simulating once for each component, and the trained BPNN can achieve all the soft faults diagnosis of the component. Experiments show that our approach is promising.

  5. Simulation of the Laki volcanoe based upon analogs of winds

    Science.gov (United States)

    Balkanski, Yves; Menut, Laurent; Jourdain, Sylvie; Garnier, Emmanuel; Eschstruth, Celia; Vrac, Matthieu; Vautard, Robert; Yiou, Pascal

    2015-04-01

    Simulation of the Laki volcanoe based upon analogs of winds We used daily surface pressure measurements from 1783 over Europe to reconstruct a year of 3D wind fields based upon the closest analog found in the 6-hourly fields from the ECMWF ERAI re-analysis from 1979 to 2013. These fields are then used to nudge the LMDZORINCA global model with a full chemical scheme and a horizontal resolution of 1.29°x0.94° with 39 vertical layers to simulate the emissions of SO2 from the volcano emitting over several months from June to August 1783. Fields of SO2 and H2SO4 were analyzed over the whole year of 1783. We inject 81 Tg (S) over the period. In France, the Royal society of medicine (Société royale de médecine) had developed for the first time a network of persons that observed both climatic variables and morbidity. The network is composed of 150 contributors over France, and has a more scattered coverage for Italy, Austria, Germany the United States and Madagascar. The measurements reported three times a day include: temperature, air pressure, air humidity wind direction and a description of the sky. Within the CHEDAR (Climate and Health Data Rescue and Modelling) project an archive of daily observations of fogs over French meteorological stations was created and registers of deaths in main cities were compiled. These data indicate that increased mortality occurred from June to September 1783 immediately following the Laki eruption when compared to the average mortality over the period from 1774 to 1789. We quantified this increase over 23 cities in France. We provide a comparison of SO2 surface concentrations and draw the following conclusions: - The days when the first manifestations of the volcano are reported over Western and Northern Europe are extremely well captured by the construction of analogs of winds for 1783. - The sharp increase and the days of heavy fogs are correlated with decreases in visibility due to the advection of sulfur from the volcanic cloud

  6. Low Voltage Analog Circuit Design Based on the Flipped Voltage Follower

    Directory of Open Access Journals (Sweden)

    Neeraj Yadav

    2012-03-01

    Full Text Available The desire for portability of electronics equipment generated a need for low power system in battery products like hearing aids, implantable cardiac pacemakers, cell phones and hand held multimedia terminals. Low voltage analog circuit design differs considerably from those of high voltage analog circuit design. This paper present the basic cell knows as “flipped voltage follower” for low voltage/ low power operation. The detailed classification of basic topologies derived from the FVF cell is presented and there is a low voltage current mirror based on FVF cell has been presented. All the Circuit has been simulated using Hspice tool 0.18µm CMOS Technology. Different quality factors such as frequency response, power consumption are considered. A compression also made between previous current mirror and new designed current mirror. The layout of the current mirror has been also designed using Cadence tool.

  7. Analog synthetic biology.

    Science.gov (United States)

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  8. Visualizing Uncertainty for Probabilistic Weather Forecasting based on Reforecast Analogs

    Science.gov (United States)

    Pelorosso, Leandro; Diehl, Alexandra; Matković, Krešimir; Delrieux, Claudio; Ruiz, Juan; Gröeller, M. Eduard; Bruckner, Stefan

    2016-04-01

    Numerical weather forecasts are prone to uncertainty coming from inaccuracies in the initial and boundary conditions and lack of precision in numerical models. Ensemble of forecasts partially addresses these problems by considering several runs of the numerical model. Each forecast is generated with different initial and boundary conditions and different model configurations [GR05]. The ensembles can be expressed as probabilistic forecasts, which have proven to be very effective in the decision-making processes [DE06]. The ensemble of forecasts represents only some of the possible future atmospheric states, usually underestimating the degree of uncertainty in the predictions [KAL03, PH06]. Hamill and Whitaker [HW06] introduced the "Reforecast Analog Regression" (RAR) technique to overcome the limitations of ensemble forecasting. This technique produces probabilistic predictions based on the analysis of historical forecasts and observations. Visual analytics provides tools for processing, visualizing, and exploring data to get new insights and discover hidden information patterns in an interactive exchange between the user and the application [KMS08]. In this work, we introduce Albero, a visual analytics solution for probabilistic weather forecasting based on the RAR technique. Albero targets at least two different type of users: "forecasters", who are meteorologists working in operational weather forecasting and "researchers", who work in the construction of numerical prediction models. Albero is an efficient tool for analyzing precipitation forecasts, allowing forecasters to make and communicate quick decisions. Our solution facilitates the analysis of a set of probabilistic forecasts, associated statistical data, observations and uncertainty. A dashboard with small-multiples of probabilistic forecasts allows the forecasters to analyze at a glance the distribution of probabilities as a function of time, space, and magnitude. It provides the user with a more

  9. Human Time Allocation in Time-based Analog of Concurrent Interval-ratio Schedules

    OpenAIRE

    TAJIMA, HIROYUKI

    1999-01-01

    Six undergraduates participated in concurrent-choice experiment with monetary reinforcers. Each subject was exposed to a time-based analog of concurrent variable-interval variable-ratio schedule with equal time interval values. The time-based analog of variable-interval schedule arranged reinforcers throughout the session, and delivered them while the schedule was chosen. The time-based analog of variable-ratio schedule arranged and immediately delivered reinforcers only while the schedule wa...

  10. Puzzling electron behavior analogous to the Braess paradox in a mesoscopic network

    Science.gov (United States)

    Toussaint, Sébastien; Faniel, Sébastien; Martins, Frederico; Pala, Marco; Desplanque, Ludovic; Wallart, Xavier; Huant, Serge; Sellier, Hermann; Bayot, Vincent; Hackens, Benoit

    A counterintuitive behavior analogous to the Braess paradox is encountered in a two-terminal mesoscopic network patterned in a two-dimensional electron system (2DES). Decreasing locally the electron density of one channel in the network paradoxically leads to an increased network conductance. Our scanning gate microscopy experiments reveals this puzzling conductance variation, thanks to tip-induced localized modifications of electron flow throughout the network's channels at low temperature, in the ballistic and coherent regime of transport. We compare the amplitude of the measured anomalous conductance variation with conductance changes induced by other mechanisms at play in the mesoscopic network, such as interference phenomena between different paths, and Coulomb blockade due to disorder-induced localized states. The robustness of this puzzling behavior is inspected by varying the global 2DES density, magnetic field and temperature. S.T. acknowledges support from the Belgian FRS-FNRS (FRIA).

  11. Puzzling electron behavior analogous to the Braess paradox in a mesoscopic networ

    Science.gov (United States)

    Toussaint, Sébastien; Faniel, Sébastien; Martins, Frederico; Pala, Marco; Desplanque, Ludovic; Wallart, Xavier; Huant, Serge; Sellier, Hermann; Bayot, Vincent; Hackens, Benoit

    A counterintuitive behavior analogous to the Braess paradox is encountered in a two-terminal mesoscopic network patterned in a two-dimensional electron system (2DES). Decreasing locally the electron density of one channel in the network paradoxically leads to an increased network conductance. Our scanning gate microscopy experiments reveals this puzzling conductance variation, thanks to tip-induced localized modifications of electron flow throughout the network's channels at low temperature, in the ballistic and coherent regime of transport. We compare the amplitude of the measured anomalous conductance variation with conductance changes induced by other mechanisms at play in the mesoscopic network, such as interference phenomena between different paths, and Coulomb blockade due to disorder-induced localized states. The robustness of this puzzling behavior is inspected by varying the global 2DES density, magnetic field and temperature S.T. acknowledges support from the Belgian FRS-FNRS (FRIA).

  12. The Analog Front-end Prototype Electronics Designed for LHAASO WCDA

    CERN Document Server

    Ma, Cong; Guo, Yu-Xiang; Liu, Jian-Feng; Liu, Shu-Bin; An, Qi

    2015-01-01

    In the readout electronics of the Water Cerenkov Detector Array (WCDA) in the Large High Altitude Air Shower Observatory (LHAASO) experiment, both high-resolution charge and time measurement are required over a dynamic range from 1 photoelectron (P.E.) to 4000 P.E. The Analog Front-end (AFE) circuit is one of the crucial parts in the whole readout electronics. We designed and optimized a prototype of the AFE through parameter calculation and circuit simulation, and conducted initial electronics tests on this prototype to evaluate its performance. Test results indicate that the charge resolution is better than 1% @ 4000 P.E. and remains better than 10% @ 1 P.E., and the time resolution is better than 0.5 ns RMS, which is better than application requirement.

  13. Low power analog readout front-end electronics for time and energy measurements

    International Nuclear Information System (INIS)

    We report on the design and measurements of an analog front-end readout electronics dedicated for silicon microstrip detectors with relatively large capacitance of the order of tens pF for time and energy measurements of incoming pulses. The front-end readout electronics is required to process input pulses with an average rate of 150 kHz/channel with low both power consumption and noise at the same time. In the presented solution the single channel is built of two different parallel processing paths: fast and slow. The fast path includes the fast CR–RC shaper with the peaking time tp=40 ns and is optimized to determine the input charge arrival time. The slow path, which consists of the slow CR–(RC)2 shaper with the peaking time tp=80 ns, is dedicated for low noise accurate energy measurement. The analog front-end electronics was implemented in UMC 180 nm CMOS technology as a prototype ASIC AFE. The AFE chip contains 8 channels with the size of 58 μm×1150 μm each. It has low power dissipation Pdiss=3.1 mW per single channel. The article presents the details of the front-end architecture and the measurement results

  14. The Use of a Solid State Analog Television Transmitter as a Superconducting Electron Gun Power Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Kulpin, K.J. Kleman, R.A. Legg

    2012-07-01

    A solid state analog television transmitter designed for 200 MHz operation is being commissioned as a radio frequency power amplifier on the Wisconsin superconducting electron gun cavity. The amplifier consists of three separate radio frequency power combiner cabinets and one monitor and control cabinet. The transmitter employs rugged field effect transistors built into one kilowatt drawers that are individually hot swappable at maximum continuous power output. The total combined power of the transmitter system is 33 kW at 200 MHz, output through a standard coaxial transmission line. A low level radio frequency system is employed to digitally synthesize the 200 MHz signal and precisely control amplitude and phase.

  15. Microcontroller based electronic load

    International Nuclear Information System (INIS)

    A microcontroller based electronic load has been designed and developed for testing of power supplies in CAT, Indore. This system is designed to operate in 4 different modes viz. constant current, constant power, constant resistance and constant resistance-inductance mode. This dynamic electronic load is very useful because a single load can be used in four different modes and different values can be emulated in each mode. It can be used as a switching load too. User interface has been provided to set the mode of operation and the set point during run time. (author)

  16. Market price simulator based on analog electrical circuit

    OpenAIRE

    Aki-Hiro Sato; Hideki Takayasu

    2001-01-01

    We constructed an analog electrical circuit which generates fluctuations in which probability density function has power law tails. In the circuit fluctuations with an arbitrary exponent of the power law can be obtained by adjusting the resistance. With this low cost circuit the random fluctuations which have the similar statistics to foreign exchang rates can be generated as fast as an expensive digital computer.

  17. Precision analog signal processor for beam position measurements in electron storage rings

    International Nuclear Information System (INIS)

    Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y position entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

  18. Demonstrations for scanning probe microscopy based on a macroscopic analogy

    Czech Academy of Sciences Publication Activity Database

    Hajková, Z.; Fejfar, Antonín; Smejkal, P.

    2013-01-01

    Roč. 90, č. 3 (2013), s. 361-363. ISSN 0021-9584 R&D Projects: GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : high school /introductory chemistry * first-year undergraduate/genera * demonstrations * interdisciplinary/multidisciplinary * analogies/transfer * atomic Subject RIV: AM - Education Impact factor: 1.001, year: 2013 http://pubs.acs.org/doi/abs/10.1021/ed3004947

  19. Solid-state reprogrammable analog resistive devices for electronic neural networks

    Science.gov (United States)

    Ramesham, R.; Thakoor, S.; Daud, T.; Thakoor, A. P.

    1990-01-01

    The fabrication and performance of WO3-based, solid-state, three-terminal device configurations as programmable analog memory elements are reported. These transistorlike device structures exhibit good resistance progammability with a remarkable resolution of a few percent of the resistive strength over a four orders of magnitude dynamic range. The most critical component of these devices is an insulating layer between the active WO3 and the cation donor layer. The progamming characteristics and operation mechanisms of the device are described, and probable reaction mechanisms critical to the device stability are discussed.

  20. Piezoelectric energy harvesting from colored fat-tailed fluctuations: An electronic analogy

    Directory of Open Access Journals (Sweden)

    J. I. Peña Rosselló

    2015-09-01

    Full Text Available Aiming to optimize piezoelectric energy harvesting from strongly col-ored fat-tailed fluctuations, we have recently studied the performance ofa monostable inertial device under a noise whose statistics depends on aparameter q (bounded for q 1.We have studied the interplay between the potential shape (interpolatingbetween square-well and harmonic-like behaviors and the noise’s statis-tics and spectrum, and showed that its output power grows as q increasesabove 1. We now report a real experiment on an electronic analog of theproposed system, which sheds light on its operating principle. Received: 20 Novembre 2014, Accepted: 7 September 2015; Edited by: C. A. Condat, G. J. Sibona; DOI:http://dx.doi.org/10.4279/PIP.070014 Cite as: J I Peña Rosselló, R Deza, J . Deza, H S Wio, Papers in Physics 7, 070014 (2015

  1. Dynamic mesh optimization based on the spring analogy

    Directory of Open Access Journals (Sweden)

    Schmidt Jonas

    2014-01-01

    Full Text Available We present an implementation of the spring analogy for three dimensional meshes in OpenFOAM. All parameters of the spring system are treated as fields that can either be pre-defined by the user, or updated at each time step according to specified geometrical regions or diffusion equations. The purpose of the method is to provide a pre-processing tool for mesh optimization. We study three simple test cases, a deformed block, an airfoil and a hill, and we analyze the evolution of skewness, non-orthogonality and aspect ratio during the approach of dynamic equilibrium.

  2. Electronic Properties of the Prussian Blue Analog Co3[Os(CN6)]2 at Low Temperatures

    Science.gov (United States)

    Wellington, T.; Ford, A.; Teizer, W.; Hilfiger, M.; Avendano, C.; Dunbar, K.

    2009-10-01

    The Prussian blue analog Co3[Os(CN6)]2 exhibits photoinduced changes of magnetic behavior as well as charge transfer induced spin transitions at low temperatures (5-10K). Magnetic measurements on the bulk material show an increased magnetic susceptibility after illumination with red light, as the analog exhibits an abrupt spin transition due to enhanced cooperativity. We are studying the electronic interactions between this Prussian blue analog and gold films of varying thickness at temperature 2Kresistance when compared to a thin film gold sample. The exact decrease varies from sample to sample, due to the disordered nature of Prussian blue analogs and the existence of water in the interstices of the lattice. However, for each sample the observed decrease is reproducible for up to two weeks.

  3. Fluorescent difluoroboron-curcumin analogs: An investigation of the electronic structures and photophysical properties

    Science.gov (United States)

    Margar, Sachin N.; Rhyman, Lydia; Ramasami, Ponnadurai; Sekar, Nagaiyan

    2016-01-01

    A comprehensive approach based on the density functional theory method was used to elicit the molecular and photophysical properties of four difluoroboron analogs of curcumin. The ground state geometry optimization, vertical absorption and the first excited state optimization were carried out using the B3LYP/6-31G(d) method. The geometry of the molecules remains planar both in the ground and excited states. There is a good correlation between the observed absorption (maximum deviation of 8%) and emission wavelength (maximum deviation of 22%) with the computed values. Different polarizability parameters were computed and compared with urea. The values obtained for the difluoroboron dyes are larger than those of urea, suggesting considerable charge transfer characteristics of the first excited state. This is further supported by the significant difference in the dipole moment. The outcome of this work should be useful towards the industrial applications of these curcumin-based dyes.

  4. An FPGA-Based Electronic Cochlea

    Directory of Open Access Journals (Sweden)

    M. P. Leong

    2003-06-01

    Full Text Available A module generator which can produce an FPGA-based implementation of an electronic cochlea filter with arbitrary precision is presented. Although hardware implementations of electronic cochlea models have traditionally used analog VLSI as the implementation medium due to their small area, high speed, and low power consumption, FPGA-based implementations offer shorter design times, improved dynamic range, higher accuracy, and a simpler computer interface. The tool presented takes filter coefficients as input and produces a synthesizable VHDL description of an application-optimized design as output. Furthermore, the tool can use simulation test vectors in order to determine the appropriate scaling of the fixed point precision parameters for each filter. The resulting model can be used as an accelerator for research in audition or as the front-end for embedded auditory signal processing systems. The application of this module generator to a real-time cochleagram display is also presented.

  5. Two-Dimensional Fourier Transform Electronic Spectroscopy of Peridinin and Peridinin Analogs

    Science.gov (United States)

    Khosravi, Soroush; Bishop, Michael; Obaid, Razib; Whitelock, Hope; Carroll, Ann Marie; Lafountain, Amy; Frank, Harry; Beck, Warren; Gibson, George; Berrah, Nora

    2016-05-01

    The peridinin chlorophyll- a protein (PCP) is a light harvesting complex in dinoflagellates that exhibits a carotenoid-to-chlorophyll (Chl) a excitation energy transfer (EET) efficiency of 85-95%. Unlike most light harvesting complexes, where the number of carotenoids is less than Chl, each subunit of PCP contains eight tightly-packed peridinins surrounding two Chl a molecules. The unusual solvent polarity dependence of the lowest excited S1 state of peridinin suggests the presence of an intramolecular charge-transfer (ICT) state. The nature of the ICT state, its coupling to the S1 of peridinin, and whether it enables the high EET efficiency is still unclear. Two-dimensional electronic Fourier transform spectroscopy (2DES) is a powerful method capable of examining these issues. The present work examines the ICT state of peridinin and peridinin analogs that have diminished ICT character. 2DES data adding new insight into the spectral signatures and nature of the ICT state in peridinin will be presented. Funded by the DoE-BES, Grant No. DE-SC0012376.

  6. Electromagnetic compatibility of new installations of digital/analog and electrical/electronic equipment in nuclear power plants

    International Nuclear Information System (INIS)

    This paper recommends electromagnetic compatibility (EMC) requirements of new digital/analog and electrical/electronic equipment installations in nuclear power plant areas including control rooms, remote shutdown panels, cable spreading rooms, equipment/relay rooms and the turbine deck. A nuclear plant electromagnetic environment (EME) consists of electromagnetic noises from portable two-way radios, arc welders, etc; and high-energy fast transients from generator and transmission / distribution voltages. Trends in current plant modifications suggest that Instrumentation and Control (I and C) systems with analog equipment are being replaced with more efficient computerized/microprocessor-based digital systems. As digital systems are evolving with higher clock frequencies and lower logic level voltages, digital equipment are more vulnerable to electromagnetic/radio frequency interference (EMI/RFI) random noise causing errors in their logic functions. US NRC Regulatory Guide (RG) 1.180, providing guidelines for evaluating EMI/RFI in safety-related I and C systems, endorsed EPRI guidelines TR-102323-RI for EMI emission/susceptibility testing and limiting practices as an acceptable qualification method of digital equipment EMC. Numerous US nuclear utilities have used these EPRI requirements in their equipment specifications. The basis for this paper is derived from these guidelines, military/industry standards, federal regulations and various international publications on EMC. Plant emission levels are selected 8dB below digital equipment susceptibility testing levels and the equipment emissions are conservatively limited to 22dB or more below these levels depending on frequency. Digital equipment is also required to satisfy the EMI limiting practices of EPRI TR-102323-R1 and IEEE 1050-1996. On the other hand, electrical/electronic equipment that operates at higher voltages at power frequency is not as vulnerable to the plant EMI as digital equipment, but could

  7. Application of carbon nanotubes and graphene for digital and analog electronics

    Science.gov (United States)

    Badmaev, Alexander

    2011-07-01

    Carbon nanomaterials, one-dimensional (1D) carbon nanotubes and two-dimensional (2D) graphene, exhibit the highest electron mobility (˜100,000 cm 2/V/s at room temperature) among all conductors, and huge current carrying capacity of more than 109 A/cm2. Additionally, single-atomic thickness provides ideal electrostatic geometry for field effect devices. These properties make carbon nanomaterials to be strong candidates to replace or supplement conventional semiconductors. Theoretical and experimental studies on individual nanotubes and graphene flakes demonstrated superior performance of carbon based field-effect transistors (FETs). However, in order to realize this potential in electronic applications, scalable synthesis and assembly of carbon nanomaterials, as well as further devices design and fabrication, still remain to be a significant challenge. In this thesis, I present our developments in order to overcome some of the critical problems in practical implementation of carbon based electronics. In our approaches, we address issues starting from the scalable controllable synthesis of carbon nanomaterials and their assembly, including design of electronic devices and material methods for their fabrication, and, finally, integration of these devices into functional circuits. This broad range of issues is tightly and often inseparably inter-connected with each other, as can be seen from an example of very large scale integrated (VLSI) silicon electronics, therefore, ultimately presenting one major goal of developing carbon based electronics. The structure of the thesis is as follows. Chapter 1 gives introduction to nano-scale carbon materials, their electronic properties and problems towards realization of carbon-based electronics. Chapter 2 presents chemical vapor deposition (CVD) methods for synthesis of carbon nanotubes and graphene. CVD synthesis methods proved to be highly promising for large scale synthesis of high quality carbon nanomaterials. The

  8. Feature evaluation and extraction based on neural network in analog circuit fault diagnosis

    Institute of Scientific and Technical Information of China (English)

    Yuan Haiying; Chen Guangju; Xie Yongle

    2007-01-01

    Choosing the right characteristic parameter is the key to fault diagnosis in analog circuit.The feature evaluation and extraction methods based on neural network are presented.Parameter evaluation of circuit features is realized by training results from neural network; the superior nonlinear mapping capability is competent for extracting fault features which are normalized and compressed subsequently.The complex classification problem on fault pattern recognition in analog circuit is transferred into feature processing stage by feature extraction based on neural network effectively, which improves the diagnosis efficiency.A fault diagnosis illustration validated this method.

  9. Investigation of analog/RF performance of staggered heterojunctions based nanowire tunneling field-effect transistors

    Science.gov (United States)

    Chakraborty, Avik; Sarkar, Angsuman

    2015-04-01

    In this paper, the analog/RF performance of an III-V semiconductor based staggered hetero-tunnel-junction (HETJ) n-type nanowire (NW) tunneling FET (n-TFET) is investigated, for the first time. The device performance figure-of-merits governing the analog/RF performance such as transconductance (gm), transconductance-to-drive current ratio (gm/IDS), output resistance (Rout), intrinsic gain and unity-gain cutoff frequency (fT) have been studied. The analog/RF performance parameters is compared between HETJ NW TFET and a homojunction (HJ) NW n-type TFET of similar dimensions. In addition to enhanced ION and subthreshold swing, a significant improvement in the analog/RF performance parameters obtained by the HETJ n-TFET over HJ counterpart for use in analog/mixed signal System-on-Chip (SoC) applications is reported. Moreover, the analog/RF performance parameters of a III-V based staggered HETJ NW TFET is also compared with a heterojunction (HETJ) NW n-type MOSFET having same material as HETJ n-TFET and equal dimension in order to provide a systematic comparison between HETJ-TFET and HETJ-MOSFET for use in analog/mixed-signal applications. The results reveal that HETJ n-TFET provides higher Rout and hence, a higher intrinsic gain, an improved gm/IDS ratio, and reasonable fT at lower values of gate-overdrive voltage as compared to the HETJ NW n-MOSFET.

  10. Planning the electron traffic in semiconductor networks: A mesoscopic analog of the Braess paradox encountered in road networks

    International Nuclear Information System (INIS)

    By combining quantum simulations of electron transport and scanning-gate microscopy, we have shown that the current transmitted through a semiconductor two-path rectangular network in the ballistic and coherent regimes of transport can be paradoxically degraded by adding a third path to the network. This is analogous to the Braess paradox occurring in classical networks. Simulations reported here enlighten the role played by congestion in the network

  11. Planning the electron traffic in semiconductor networks: A mesoscopic analog of the Braess paradox encountered in road networks

    Science.gov (United States)

    Huant, S.; Baltazar, S.; Liu, P.; Sellier, H.; Hackens, B.; Martins, F.; Bayot, V.; Wallart, X.; Desplanque, L.; Pala, M. G.

    2013-12-01

    By combining quantum simulations of electron transport and scanning-gate microscopy, we have shown that the current transmitted through a semiconductor two-path rectangular network in the ballistic and coherent regimes of transport can be paradoxically degraded by adding a third path to the network. This is analogous to the Braess paradox occurring in classical networks. Simulations reported here enlighten the role played by congestion in the network.

  12. Planning the electron traffic in semiconductor networks: A mesoscopic analog of the Braess paradox encountered in road networks

    Energy Technology Data Exchange (ETDEWEB)

    Huant, S.; Liu, P.; Sellier, H. [Institut Néel, CNRS and Université Joseph Fourier, BP 166, F-38042 Grenoble (France); Baltazar, S. [IMEP-LAHC, Grenoble INP, Minatec, BP 257, F-38016 Grenoble, France and Departamento de Fısica, Universidad de Santiago de Chile, Santiago 9170124 (Chile); Hackens, B.; Martins, F. [Université Catholique de Louvain, IMCN/NAPS, Louvain-la-Neuve (Belgium); Bayot, V. [Institut Néel, CNRS and Université Joseph Fourier, BP 166, F-38042 Grenoble, France and Université Catholique de Louvain, IMCN/NAPS, Louvain-la-Neuve (Belgium); Wallart, X.; Desplanque, L. [IEMN, UMR CNRS 8520, UST Lille, BP 60069, F-59652 Villeneuve d' Ascq (France); Pala, M. G. [IMEP-LAHC, Grenoble INP, Minatec, BP 257, F-38016 Grenoble (France)

    2013-12-04

    By combining quantum simulations of electron transport and scanning-gate microscopy, we have shown that the current transmitted through a semiconductor two-path rectangular network in the ballistic and coherent regimes of transport can be paradoxically degraded by adding a third path to the network. This is analogous to the Braess paradox occurring in classical networks. Simulations reported here enlighten the role played by congestion in the network.

  13. FDSAC-SPICE: fault diagnosis software for analog circuit based on SPICE simulation

    Science.gov (United States)

    Cao, Yiqin; Cen, Zhao-Hui; Wei, Jiao-Long

    2009-12-01

    This paper presents a novel fault diagnosis software (called FDSAC-SPICE) based on SPICE simulator for analog circuits. Four important techniques in AFDS-SPICE, including visual user-interface(VUI), component modeling and fault modeling (CMFM), fault injection and fault simulation (FIFS), fault dictionary and fault diagnosis (FDFD), greatly increase design-for-test and diagnosis efficiency of analog circuit by building a fault modeling-injection-simulationdiagnosis environment to get prior fault knowledge of target circuit. AFDS-SPICE also generates accurate fault coverage statistics that are tied to the circuit specifications. With employing a dictionary diagnosis method based on node-signalcharacters and regular BPNN algorithm, more accurate and effective diagnosis results are available for analog circuit with tolerance.

  14. An Analog Multilayer Perceptron Neural Network for a Portable Electronic Nose

    Directory of Open Access Journals (Sweden)

    Chih-Heng Pan

    2012-12-01

    Full Text Available This study examines an analog circuit comprising a multilayer perceptron neural network (MLPNN. This study proposes a low-power and small-area analog MLP circuit to implement in an E-nose as a classifier, such that the E-nose would be relatively small, power-efficient, and portable. The analog MLP circuit had only four input neurons, four hidden neurons, and one output neuron. The circuit was designed and fabricated using a 0.18 μm standard CMOS process with a 1.8 V supply. The power consumption was 0.553 mW, and the area was approximately 1.36 × 1.36 mm2. The chip measurements showed that this MLPNN successfully identified the fruit odors of bananas, lemons, and lychees with 91.7% accuracy.

  15. A novel prediction method about single components of analog circuits based on complex field modeling.

    Science.gov (United States)

    Zhou, Jingyu; Tian, Shulin; Yang, Chenglin

    2014-01-01

    Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments. PMID:25147853

  16. Canadian Tire Money: An Analogy for Use When Discussing Weak Acid Strong Base Titrations

    Science.gov (United States)

    Last, Arthur M.

    2003-12-01

    A simple analogy can often provide an instructor with a means of helping students to understand an unfamiliar concept. An analogy involving money can be particularly helpful as most students have experience in dealing with a range of financial transactions in their everyday lives. In this article, use is made of the practice of one well-known Canadian retail chain in returning to its customers a small percentage of an item's purchase price in the form of imitation bank notes that can subsequently be spent in the chain's stores. An analogy is drawn between this practice and the determination of the pKa of a weak acid by titrating it with a strong base, taking into account the hydrolysis of the anion produced.

  17. Demonstration of a 3-bit optical digital-to-analog converter based on silicon microring resonators.

    Science.gov (United States)

    Yang, Lin; Ding, Jianfeng; Chen, Qiaoshan; Zhou, Ping; Zhang, Fanfan; Zhang, Lei

    2014-10-01

    We propose an N-bit optical digital-to-analog converter based on silicon microring resonators (MRRs), which can transform an N-bit electrical digital signal to an optical analog signal. A 3-bit optical digital-to-analog convertor is fabricated as proof of concept through a CMOS-compatible process on a silicon-on-insulator platform. The silicon MRRs are modulated through the electric-field-induced carrier injection in forward biased PN junctions embedded in the ring waveguides. The electro-optical 3-dB bandwidths of the silicon MRRs are approximately 800 MHz. The device works well at a speed of 500  MSample/s under driving voltage swings of 0.75 V. PMID:25360972

  18. Property-Based Monitoring of Analog and Mixed-Signal Systems

    Science.gov (United States)

    Havlicek, John; Little, Scott; Maler, Oded; Nickovic, Dejan

    In the recent past, there has been a steady growth of the market for consumer embedded devices such as cell phones, GPS and portable multimedia systems. In embedded systems, digital, analog and software components are combined on a single chip, resulting in increasingly complex designs that introduce richer functionality on smaller devices. As a consequence, the potential insertion of errors into a design becomes higher, yielding an increasing need for automated analog and mixed-signal validation tools. In the purely digital setting, formal verification based on properties expressed in industrial specification languages such as PSL and SVA is nowadays successfully integrated in the design flow. On the other hand, the validation of analog and mixed-signal systems still largely depends on simulation-based, ad-hoc methods. In this tutorial, we consider some ingredients of the standard verification methodology that can be successfully exported from digital to analog and mixed-signal setting, in particular property-based monitoring techniques. Property-based monitoring is a lighter approach to the formal verification, where the system is seen as a "black-box" that generates sets of traces, whose correctness is checked against a property, that is its high-level specification. Although incomplete, monitoring is effectively used to catch faults in systems, without guaranteeing their full correctness.

  19. A self-testing method of large analog circuits in electronic embedded systems

    Energy Technology Data Exchange (ETDEWEB)

    Czaja, Z, E-mail: zbczaja@pg.gda.p [Gdansk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Optoelectronics and Electronic Systems, ul. G. Narutowicza 11/12, 80-233 Gdansk (Poland)

    2010-07-01

    A new self-testing method of high-order filters consisting of a chain of first- or second-order filter units of mixed-signal electronic embedded systems controlled by microcontrollers or DSPs is presented in the paper. The main idea of the method bases on the fact that the signal response of the given filter unit is treated as the signal stimulation of the next filter unit. Thanks to this, a simple reconfigurable BIST consisting of only internal devices of the microcontroller controlling the system was obtained.

  20. An analog VLSI real time optical character recognition system based on a neural architecture

    International Nuclear Information System (INIS)

    In this paper a real time Optical Character Recognition system is presented: it is based on a feature extraction module and a neural network classifier which have been designed and fabricated in analog VLSI technology. Experimental results validate the circuit functionality. The results obtained from a validation based on a mixed approach (i.e., an approach based on both experimental and simulation results) confirm the soundness and reliability of the system

  1. Communication disruption of guava moth (Coscinoptycha improbana) using a pheromone analog based on chain length.

    Science.gov (United States)

    Suckling, D M; Dymock, J J; Park, K C; Wakelin, R H; Jamieson, L E

    2013-09-01

    The guava moth, Coscinoptycha improbana, an Australian species that infests fruit crops in commercial and home orchards, was first detected in New Zealand in 1997. A four-component pheromone blend was identified but is not yet commercially available. Using single sensillum recordings from male antennae, we established that the same olfactory receptor neurons responded to two guava moth sex pheromone components, (Z)-11-octadecen-8-one and (Z)-12-nonadecen-9-one, and to a chain length analog, (Z)-13-eicosen-10-one, the sex pheromone of the related peach fruit moth, Carposina sasakii. We then field tested whether this non-specificity of the olfactory neurons might enable disruption of sexual communication by the commercially available analog, using male catch to synthetic lures in traps in single-tree, nine-tree and 2-ha plots. A disruptive pheromone analog, based on chain length, is reported for the first time. Trap catches for guava moth were disrupted by three polyethylene tubing dispensers releasing the analog in single-tree plots (86% disruption of control catches) and in a plots of nine trees (99% disruption). Where peach fruit moth pheromone dispensers were deployed at a density of 1000/ha in two 2-ha areas, pheromone traps for guava moth were completely disrupted for an extended period (up to 470 days in peri-urban gardens in Mangonui and 422 days in macadamia nut orchards in Kerikeri). In contrast, traps in untreated areas over 100 m away caught 302.8 ± 128.1 moths/trap in Mangonui and 327.5 ± 78.5 moths/ trap in Kerikeri. The longer chain length in the pheromone analog has greater longevity than the natural pheromone due to its lower volatility. Chain length analogs may warrant further investigation for mating disruption in Lepidoptera, and screening using single-sensillum recording is recommended. PMID:24026215

  2. Electron microscopic aspects of the effects of certain prostaglandin analogs on mouse testes.

    Science.gov (United States)

    Sava, Anca; Motoc, Andrei Gheorghe Marius; Stan, Cristinel Ionel

    2015-01-01

    Prostaglandins were highlighted in the seminal plasma and then in the rest of the male and female genital tract. Prostaglandin analogs, firstly used in obstetrics and gynecology, are now widespread in both sexes, especially in the treatment of gastric and duodenal ulcers, glaucoma, etc. Therefore, we tried to highlight the effects of repeated administration of Cloprostenol and CIPG isopropyl ester (both prostaglandin F2α analogs) for the male gonad. In our experiment, we used Cloprostenol and CIPG isopropyl ester. We used three groups of white, male mice, aged 50-80 days, kept in standard laboratory conditions, which received the same feed. Each group included 12 mice. The first batch was the control group and received no substance at all. The second batch received 25 μg/kg of Cloprostenol dose per body per day, intraperitoneal administration (a single dose per day) on a daily basis for a four weeks period of time. The third batch received a 25 μg/kg CIPG isopropyl ester dose per body/day intraperitoneal administration (a single dose per day) on a daily basis for a four weeks period of time. After 7, 14 and 28 days of treatment, we sacrificed four animals in each of the batches by cutting their carotid arteries. The prostanoid analogs we used, Cloprostenol and CIPG isopropyl ester, have similar actions on male gonad in mice. These analogs induced significant changes in the evolution of the spermatogenesis and spermiogenesis. In relation to the treatment duration there were cellular changes suggesting apoptosis in different stages. With regard to spermiogenesis, the ultrastructural aspects indicate a decrease of the sperm structuring processes, especially in the acrosomal apparatus and chromatin. PMID:26429171

  3. π-Radical to σ-Radical Tautomerization in One-Electron-Oxidized 1-Methylcytosine and Its Analogs.

    Science.gov (United States)

    Adhikary, Amitava; Kumar, Anil; Bishop, Casandra T; Wiegand, Tyler J; Hindi, Ragda M; Adhikary, Ananya; Sevilla, Michael D

    2015-09-01

    In this work, iminyl σ-radical formation in several one-electron-oxidized cytosine analogs, including 1-MeC, cidofovir, 2'-deoxycytidine (dCyd), and 2'-deoxycytidine 5'-monophosphate (5'-dCMP), were investigated in homogeneous, aqueous (D2O or H2O) glassy solutions at low temperatures by employing electron spin resonance (ESR) spectroscopy. Upon employing density functional theory (DFT) (DFT/B3LYP/6-31G* method), the calculated hyperfine coupling constant (HFCC) values of iminyl σ-radical agree quite well with the experimentally observed ones, thus confirming its assignment. ESR and DFT studies show that the cytosine iminyl σ-radical is a tautomer of the deprotonated cytosine π-cation radical [cytosine π-aminyl radical, C(N4-H)(•)]. Employing 1-MeC samples at various pHs ranging from ca. 8 to 11, ESR studies show that the tautomeric equilibrium between C(N4-H)(•) and the iminyl σ-radical at low temperature is too slow to be established without added base. ESR and DFT studies agree that, in the iminyl σ-radical, the unpaired spin is localized on the exocyclic nitrogen (N4) in an in-plane pure p-orbital. This gives rise to an anisotropic nitrogen hyperfine coupling (Azz = 40 G) from N4 and a near isotropic β-nitrogen coupling of 9.7 G from the cytosine ring nitrogen at N3. Iminyl σ-radical should exist in its N3-protonated form, as the N3-protonated iminyl σ-radical is stabilized in solution by over 30 kcal/mol (ΔG = -32 kcal/mol) over its conjugate base, the N3-deprotonated form. This is the first observation of an isotropic β-hyperfine ring nitrogen coupling in an N-centered DNA radical. Our theoretical calculations predict that the cytosine iminyl σ-radical can be formed in double-stranded DNA by a radiation-induced ionization-deprotonation process that is only 10 kcal/mol above the lowest energy path. PMID:26237072

  4. Analogy for Drude's free electron model to promote students' understanding of electric circuits in lower secondary school

    Science.gov (United States)

    de Almeida, Maria José BM; Salvador, Andreia; Costa, Maria Margarida RR

    2014-12-01

    Aiming at a deep understanding of some basic concepts of electric circuits in lower secondary schools, this work introduces an analogy between the behavior of children playing in a school yard with a central lake, subject to different conditions, rules, and stimuli, and Drude's free electron model of metals. Using this analogy from the first school contacts with electric phenomena, one can promote students' understanding of concepts such as electric current, the role of generators, potential difference effects, energy transfer, open and closed circuits, resistances, and their combinations in series and parallel. One believes that through this analogy well-known previous misconceptions of young students about electric circuit behaviors can be overcome. Furthermore, students' understanding will enable them to predict, and justify with self-constructed arguments, the behavior of different elementary circuits. The students' predictions can be verified—as a challenge of self-produced understanding schemes—using laboratory experiments. At a preliminary stage, our previsions were confirmed through a pilot study with three classrooms of 9th level Portuguese students.

  5. Energy storage in the photosynthetic electron-transport chain. An analogy with Michaelis-Menten kinetics

    Directory of Open Access Journals (Sweden)

    DEJAN MARKOVIC

    2003-09-01

    Full Text Available Simultaneous measurements of fluorescence and thermal emission have been performed by applying combined fluorescence and photoacoustic techniques on isolated thylakoids pretreated by prolonged illumination with saturating light. The traces were used to create Lineweaver-Burk type plots, proving clearly at least a formal analogy between the kinetics of the mechanisms governing fluorescence and thermal emission from isolated thylakoids and Michaelis-Menten kinetics of enzymatic reactions. Two characteristic parameters were calculated from them (energy storage and half-saturation light intensity in order to obtain a basic, initial response of the photosynthetic apparatus functioning under photoinhibition stress.

  6. Simplified 2-bit photonic digital-to-analog conversion unit based on polarization multiplexing

    Science.gov (United States)

    Zhang, Fangzheng; Gao, Bindong; Ge, Xiaozhong; Pan, Shilong

    2016-03-01

    A 2-bit photonic digital-to-analog conversion unit is proposed and demonstrated based on polarization multiplexing. The proposed 2-bit digital-to-analog converter (DAC) unit is realized by optical intensity weighting and summing, and its complexity is greatly reduced compared with the traditional 2-bit photonic DACs. Performance of the proposed 2-bit DAC unit is experimentally investigated. The established 2-bit DAC unit achieves a good linear transfer function, and the effective number of bits is calculated to be 1.3. Based on the proposed 2-bit DAC unit, two DAC structures with higher (>2) bit resolutions are proposed and discussed, and the system complexity is expected to be reduced by half by using the proposed technique.

  7. ANALOG I/O MODULE TEST SYSTEM BASED ON EPICS CA PROTOCOL AND ACTIVEX CA INTERFACE

    International Nuclear Information System (INIS)

    Analog input (ADC) and output (DAC) modules play a substantial role in device level control of accelerator and large experiment physics control system. In order to get the best performance some features of analog modules including linearity, accuracy, crosstalk, thermal drift and so on have to be evaluated during the preliminary design phase. Gain and offset error calibration and thermal drift compensation (if needed) may have to be done in the implementation phase as well. A natural technique for performing these tasks is to interface the analog VO modules and GPIB interface programmable test instruments with a computer, which can complete measurements or calibration automatically. A difficulty is that drivers of analog modules and test instruments usually work on totally different platforms (vxworks VS Windows). Developing new test routines and drivers for testing instruments under VxWorks (or any other RTOS) platform is not a good solution because such systems have relatively poor user interface and developing such software requires substantial effort. EPICS CA protocol and ActiveX CA interface provide another choice, a PC and LabVIEW based test system. Analog 110 module can be interfaced from LabVIEW test routines via ActiveX CA interface. Test instruments can be controlled via LabVIEW drivers, most of which are provided by instrument vendors or by National Instruments. Labview also provides extensive data analysis and process functions. Using these functions, users can generate powerful test routines very easily. Several applications built for Spallation Neutron Source (SNS) Beam Loss Monitor (BLM) system are described in this paper

  8. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  9. Wideband Analog Transmission System Based on the External Intensity Electro-Optic Modulator

    Directory of Open Access Journals (Sweden)

    Jiri Svarny

    2016-01-01

    Full Text Available The work deals with design and integration of an analog electro-optic transmission system suitable for some specialized tasks of diagnostics and measurements. The system is based on principle of external intensity modulation of fiber guided laser radiation. Besides wideband and almost lossless transmission the system tolerates extreme length of the transmitting medium and ensures ultimate galvanic barrier between the input and output.

  10. Modular Hybrid Energy Concept Employing a Novel Control Structure Based on a Simple Analog System

    OpenAIRE

    PETREUS, D.; DARABAN S.; CIRSTEA, M.

    2016-01-01

    This paper proposes a novel control topology which enables the setup of a low cost analog system leading to the implementation of a modular energy conversion system. The modular concept is based on hybrid renewable energy (solar and wind) and uses high voltage inverters already available on the market. An important feature of the proposed topology is a permanently active current loop, which assures short circuit protection and simplifies the control loops compensation. The inn...

  11. Design and Exploration of Low-Power Analog to Information Conversion Based on Compressed Sensing

    OpenAIRE

    Mamaghanian, Hossein; Khaled, Nadia; Atienza Alonso, David; Vandergheynst, Pierre

    2012-01-01

    The long-standing analog-to-digital conversion paradigm based on Shannon/Nyquist sampling has been challenged lately, mostly in situations such as radar and communication signal processing where signal bandwidth is so large that sampling architectures constraints are simply not manageable. Compressed Sensing (CS) [1], [2], [3] is a new emerging signal acquisition/compression paradigm that offers a striking alternative to traditional signal acquisition. CS states that a signal having a sparse ...

  12. Time and Frequency Domain Investigation of Selected Memristor Based Analog Circuits

    OpenAIRE

    Dongale, T. D.; Gaikwad, P. K.; Kamat, R. K.

    2016-01-01

    In this paper we investigate few memristor based analog circuits namely the phase shift oscillator, integrator and differentiator which have been explored numerously using the traditional lumped components. We use LTspice-IV platform for simulation of the above said circuits. The investigation resorts to the nonlinear dopent drift model of memristor and the window function portrayed in the literature for nonlinearity realization. The results of our investigations depict good agreement with th...

  13. Improved Design of Radiation Hardened, Wide-Temperature Analog and Mixed-Signal Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA space exploration missions require the electronics for avionic systems, components, and controllers that are capable of operating in the extreme temperature...

  14. 模拟电子技术实践训练课程设计%Design of analog electronic technology practice training course

    Institute of Scientific and Technical Information of China (English)

    戴杨

    2015-01-01

    The process and method of analog electronic tranining curriculum design and practice training was described. Based on the characteristics of curriculum theory, combined with the actual circuit board components, the production process, the comprehensive use of teaching practice, the analog electronic technology theory knowledge implanted into the practical skills training, the implementation of the training process careful arrangement, the expansion of student practice, to truly apply their knowledge, study, consolidate the students to understand the theory of curriculum.%文章叙述了模拟电子技术实训课程设计的方法和实践训练的过程。基于理论课程的特点,并结合实际电路板部件生产过程,综合运用实践教学,把模拟电子技术的理论知识植入到实践技能训练中,实施仔细的实训过程安排,扩展学生操作练习,真正做到学以致用、学有所用,巩固了学生对理论课程的理解。

  15. A column-based two-stage analog-to-digital converter for uncooled microbolometer arrays

    Science.gov (United States)

    Toprak, Alperen; Tepegoz, Murat; Akin, Tayfun

    2009-05-01

    This paper presents a column-based, two-stage, 12-bit analog-to-digital converter structure designed for uncooled microbolometer arrays. On-chip analog-to-digital converters prevent the degradation of sensitive analog output by external noise sources as well as providing a more integrated functionality. Despite these advantages, the area and power constraints limit the usage of high performance converters. This paper presents a new structure that provides a balance between area, power, and performance. The structure is composed of two stages: a tracking ADC stage running at each column during integration and a successive approximation ADC stage which is shared by a number of columns depending on the array size and operation frequency. The tracking ADC operates during the integration time, while the second ADC starts after the integration is completed. The converter includes self-calibration to lower the effect of process variations and digital correction mechanisms to eliminate the need for low-offset comparators. The simulations and theoretical calculations based on the simulation results show that the total power dissipation of the proposed structure will be approximately 73.7 mW and 88.4 mW on a 320x240 array operating at 60 Hz and 384x288 array operating at 50 Hz, respectively.

  16. Impact of Analog IC Impairments in SiPM Interface Electronics

    OpenAIRE

    Dey, Samrat; Lewellen, Thomas K.; Miyaoka, Robert S.; Rudell, Jacques C.

    2012-01-01

    The recent realization of Silicon Photomultiplier (SiPM) devices as solid-state detectors for Positron Emission Tomography holds the promise of improving image resolution, integrating a significant portion of the interface electronics, and potentially lowering the power consumption. Our lab has previously reported on novel board-level readout electronics for an 8×8 silicon photomultiplier (SiPM) array featuring row/column summation technique to reduce the hardware requirements for signal proc...

  17. Component-Level Electronic-Assembly Repair (CLEAR) Spacecraft Circuit Diagnostics by Analog and Complex Signature Analysis

    Science.gov (United States)

    Oeftering, Richard C.; Wade, Raymond P.; Izadnegahdar, Alain

    2011-01-01

    The Component-Level Electronic-Assembly Repair (CLEAR) project at the NASA Glenn Research Center is aimed at developing technologies that will enable space-flight crews to perform in situ component-level repair of electronics on Moon and Mars outposts, where there is no existing infrastructure for logistics spares. These technologies must provide effective repair capabilities yet meet the payload and operational constraints of space facilities. Effective repair depends on a diagnostic capability that is versatile but easy to use by crew members that have limited training in electronics. CLEAR studied two techniques that involve extensive precharacterization of "known good" circuits to produce graphical signatures that provide an easy-to-use comparison method to quickly identify faulty components. Analog Signature Analysis (ASA) allows relatively rapid diagnostics of complex electronics by technicians with limited experience. Because of frequency limits and the growing dependence on broadband technologies, ASA must be augmented with other capabilities. To meet this challenge while preserving ease of use, CLEAR proposed an alternative called Complex Signature Analysis (CSA). Tests of ASA and CSA were used to compare capabilities and to determine if the techniques provided an overlapping or complementary capability. The results showed that the methods are complementary.

  18. Analogies in optics and micro electronics selected contributions on recent developments

    CERN Document Server

    Lenstra, Daan

    1990-01-01

    This book gives an account of a number of recent developments in two different subfields of research, optics and micro--electronics. The leading principle in presenting them together in one book is the striking similarity between a variety of notions in these two research areas. We mention in this respect tunneling, quantum interference and localization, which are important concepts in quantummechanics and more specifically in condensed matter physics. Miniaturization in solid state engineering has led to new phenomena in which these concepts play their significant roles. As it is the wave character of electrons which is strongly emphasized in these phenomena one's attention is quite naturally directed to the field of optics in which the above quantum-mechanical notions all seem to have their direct classical wavemechanical counterparts. Both micro--electronics and optics have been and still are in a mode of intensifying activity. The possibilities to technically "translate" devices developed within one resea...

  19. Teaching Diffraction of Light and Electrons: Classroom Analogies to Classic Experiments

    Science.gov (United States)

    Velentzas, Athanasios

    2014-01-01

    Diffraction and interference are phenomena that demonstrate the wave nature of light and of particles. Experiments relating to the diffraction/interference of light can easily be carried out in an educational lab, but it may be impossible to perform experiments involving electrons because of the lack of specialized equipment needed for such…

  20. Parameter estimation of analog circuits based on the fractional wavelet method

    Science.gov (United States)

    Yong, Deng; He, Zhang

    2015-03-01

    Aiming at the problem of parameter estimation in analog circuits, a new approach is proposed. The approach is based on the fractional wavelet to derive the Volterra series model of the circuit under test (CUT). By the gradient search algorithm used in the Volterra model, the unknown parameters in the CUT are estimated and the Volterra model is identified. The simulations show that the parameter estimation results of the proposed method in the paper are better than those of other parameter estimation methods. Project supported by the Key Research Project of Sichuan Provincial Department of Education, China (No. 13ZA0186).

  1. Study of the electron transfer in analog compounds of the Prussia blue

    International Nuclear Information System (INIS)

    As answer to the necessity of the search of new nano structured materials, the present work was carried out that it studies the electron transfer in compound similar of the Prussia blue (CAAP), which are representative molecular materials, because its chromophore, magnetic, and electric properties, depend mainly on the processes that are made in their levels or orbital energy. It is known that these made up with octahedra symmetry that its are presented in form of powders, suffer processes of electron transfer when its are exposed to external stimulation by means of light (embracing the regions from the ultraviolet one until the infrared in the electromagnetic spectrum), because they are made up of mixed valency. To know that types of electronic transfers are those that are made in the study materials, 4 series of CAAP its were synthesized by the method of mixtures of aqueous solutions: M[Fe+3CN)6]2nH2O, M[Cr+3(CN)6]2nH2O, M[Mn+3(CN)6]3nH2O y M[Co+3(CN)6]3nH2O, and later on studied by means of the electron spectroscopy technique with a UV-SENSE spectrophotometer (Perkin-Elmer) in or n range of work of 250 to 1100 nm. Because to discuss the electronic structures of any compound, it is required the calculation of the energy levels, they took like reference the data tabulated by John Alexander and Harry Gray calculated by the modified theoretical approach of Wolfsberg-Helmhoz. When comparing the obtained spectra with the theoretical data, it was concludes that in the CAAP, its are carried out electronic transfers among orbital molecular metallic of the type d → d, and load transfer (TC) among orbital molecular of the ligand and metal. When being carried out a load transfer in the CAAP that initially are made up of under-spin these its are photoinduced to an excited state of high spin. In consequence it is possible to vary the interactions among the metals of transition of the CAAP and the ligands, allowing the extension of coordinated phenomena (as the magnetism

  2. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  3. Power pulsing scheme for analog and digital electronics of the vertex detectors at CLIC

    CERN Document Server

    Blanchot, Georges

    2015-01-01

    The precision requirements of the vertex detector at CLIC impose strong limitations on the mass of such a detector (< 0.2% of a radiation length, Xo, per layer). To achieve such a low material budget, ultra-thin hybrid pixel detectors are foreseen, while the mass for cooling and services will be reduced by implementing a power pulsing scheme that takes advantage of the low duty cycle of the accelerator. The principal aim is to achieve significant power reduction without compromising the power integrity supplied to the front-end electronics. This report summarises the study of a power pulsing scheme to power the vertex barrel electronics of the future CLIC experiment. Its main goal is to describe in more detail what has been already presented in TWEPP conferences and other presentations. The report can therefore serve as an operator manual for future use and development of the system

  4. Optical Analog-to-digital Conversion Scheme Based on Tunable Fabry-Perot Resonator

    Institute of Scientific and Technical Information of China (English)

    LI Zheng

    2007-01-01

    Proposed is an interference type of optical analog-to-digital conversion(ADC). The refractive index of Fabry-Perot cavity changes with different voltages. The Fabry-Perot resonator converts electronic intensity into light wavelength through selecting lights of different wavelengthes. The parameters of the scheme are acquired with the transmission matrix of optical element and the time of steady-state light field. The maximum sampling speedes of 4-bit, 6-bit, 7-bit, 8-bit and 9-bit(ADC) are 1.695×1010 count/s, 4.33×109 count/s, 2.38×109 count/s, 1.24×109 count/s and 5.9×108 count/s, respectively.

  5. Work in progress-role of learning strategies in electrical circuits and analog electronics courses

    OpenAIRE

    Ramírez Echeverry, Jhon Jairo; Olarte Dussan, Fredy Andres; García Carrillo, Àgueda

    2014-01-01

    This work-in-progress describes a study intended to determine whether self-regulated learning strategies influence the academic performance of students from the Department of Electrical and Electronics Engineering at Universidad Nacional de Colombia. This research was conducted with 396 students in two terms, who were surveyed about their use of learning strategies using the CEAM II psychometric tool. Later, it was analyzed whether a significant correlation exists between the scores obtained ...

  6. Carbon Nanotube Based Molecular Electronics

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1998-01-01

    Carbon nanotubes and the nanotube heterojunctions have recently emerged as excellent candidates for nanoscale molecular electronic device components. Experimental measurements on the conductivity, rectifying behavior and conductivity-chirality correlation have also been made. While quasi-one dimensional simple heterojunctions between nanotubes with different electronic behavior can be generated by introduction of a pair of heptagon-pentagon defects in an otherwise all hexagon graphene sheet. Other complex 3- and 4-point junctions may require other mechanisms. Structural stability as well as local electronic density of states of various nanotube junctions are investigated using a generalized tight-binding molecular dynamics (GDBMD) scheme that incorporates non-orthogonality of the orbitals. The junctions investigated include straight and small angle heterojunctions of various chiralities and diameters; as well as more complex 'T' and 'Y' junctions which do not always obey the usual pentagon-heptagon pair rule. The study of local density of states (LDOS) reveal many interesting features, most prominent among them being the defect-induced states in the gap. The proposed three and four pointjunctions are one of the smallest possible tunnel junctions made entirely of carbon atoms. Furthermore the electronic behavior of the nanotube based device components can be taylored by doping with group III-V elements such as B and N, and BN nanotubes as a wide band gap semiconductor has also been realized in experiments. Structural properties of heteroatomic nanotubes comprising C, B and N will be discussed.

  7. An analog integrated signal processing circuit for on-chip diffusion-based gas analysis

    International Nuclear Information System (INIS)

    In diffusion-based gas analysis, the transient of gas diffusion process is recorded by a generic gas sensor to serve as a fingerprint for qualitative and quantitative analysis of gaseous samples. Following the acquisition of these specific signals, any standalone gas analyzer requires a pattern recognition system for pattern classification. The classic digital pattern recognition methods require computing hardware of adequate computational throughput. In this paper, we have followed a straightforward mathematical procedure to relate the signals to their associated target gases. We have shown that the procedure can be implemented by a set of analog functions. Based on the results, we have designed an analog integrated circuit, in 0.18 µm standard CMOS process, for processing the diffusion-based transient signals. The main circuit components are a low-pass filter, the differentiator, the feature extractor and an artificial neural network. The output of the circuit is a 2-bit binary code that specifies the target gas. The circuit successfully classified four alcoholic vapors by processing the experimentally obtained response patterns. The proposed signal processing circuit, the semiconductor gas sensor and the diffusion channel can all be implemented on a single substrate to fabricate an integrated micro gas analyzer. (paper)

  8. Effective Low-Power Wearable Wireless Surface EMG Sensor Design Based on Analog-Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Mohammadreza Balouchestani

    2014-12-01

    Full Text Available Surface Electromyography (sEMG is a non-invasive measurement process that does not involve tools and instruments to break the skin or physically enter the body to investigate and evaluate the muscular activities produced by skeletal muscles. The main drawbacks of existing sEMG systems are: (1 they are not able to provide real-time monitoring; (2 they suffer from long processing time and low speed; (3 they are not effective for wireless healthcare systems because they consume huge power. In this work, we present an analog-based Compressed Sensing (CS architecture, which consists of three novel algorithms for design and implementation of wearable wireless sEMG bio-sensor. At the transmitter side, two new algorithms are presented in order to apply the analog-CS theory before Analog to Digital Converter (ADC. At the receiver side, a robust reconstruction algorithm based on a combination of ℓ1-ℓ1-optimization and Block Sparse Bayesian Learning (BSBL framework is presented to reconstruct the original bio-signals from the compressed bio-signals. The proposed architecture allows reducing the sampling rate to 25% of Nyquist Rate (NR. In addition, the proposed architecture reduces the power consumption to 40%, Percentage Residual Difference (PRD to 24%, Root Mean Squared Error (RMSE to 2%, and the computation time from 22 s to 9.01 s, which provide good background for establishing wearable wireless healthcare systems. The proposed architecture achieves robust performance in low Signal-to-Noise Ratio (SNR for the reconstruction process.

  9. Effective low-power wearable wireless surface EMG sensor design based on analog-compressed sensing.

    Science.gov (United States)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2014-01-01

    Surface Electromyography (sEMG) is a non-invasive measurement process that does not involve tools and instruments to break the skin or physically enter the body to investigate and evaluate the muscular activities produced by skeletal muscles. The main drawbacks of existing sEMG systems are: (1) they are not able to provide real-time monitoring; (2) they suffer from long processing time and low speed; (3) they are not effective for wireless healthcare systems because they consume huge power. In this work, we present an analog-based Compressed Sensing (CS) architecture, which consists of three novel algorithms for design and implementation of wearable wireless sEMG bio-sensor. At the transmitter side, two new algorithms are presented in order to apply the analog-CS theory before Analog to Digital Converter (ADC). At the receiver side, a robust reconstruction algorithm based on a combination of ℓ1-ℓ1-optimization and Block Sparse Bayesian Learning (BSBL) framework is presented to reconstruct the original bio-signals from the compressed bio-signals. The proposed architecture allows reducing the sampling rate to 25% of Nyquist Rate (NR). In addition, the proposed architecture reduces the power consumption to 40%, Percentage Residual Difference (PRD) to 24%, Root Mean Squared Error (RMSE) to 2%, and the computation time from 22 s to 9.01 s, which provide good background for establishing wearable wireless healthcare systems. The proposed architecture achieves robust performance in low Signal-to-Noise Ratio (SNR) for the reconstruction process. PMID:25526357

  10. Design of Multi-Valued Quaternary Based Analog-to-Digital Converter

    Directory of Open Access Journals (Sweden)

    A. H.M.Z. Alam

    2009-01-01

    Full Text Available Problem statement: The design of multi-valued quaternary based Analog-to-Digital Converter (ADC circuit was presented. The ADC generates multi-valued logic outputs rather than the conventional binary output system to overall reduction in circuit complexity and size. Approach: Design was implemented using pipeline ADC architecture and was simulated using model parameters based on standard 0.13 µm CMOS process. Results: Performance analysis of the design showed desirable performance parameters in terms of response, low power consumption, and a sampling rate of 10 MHz at a supply voltage of 1.3V was achieved. Conclusion/Recommendations: The ADC design was suitable for the needs of mixed-signal integrated circuit design and can be implemented as a conversion circuit for systems based on multiple-valued logic design.

  11. Event-Based Computation of Motion Flow on a Neuromorphic Analog Neural Platform.

    Science.gov (United States)

    Giulioni, Massimiliano; Lagorce, Xavier; Galluppi, Francesco; Benosman, Ryad B

    2016-01-01

    Estimating the speed and direction of moving objects is a crucial component of agents behaving in a dynamic world. Biological organisms perform this task by means of the neural connections originating from their retinal ganglion cells. In artificial systems the optic flow is usually extracted by comparing activity of two or more frames captured with a vision sensor. Designing artificial motion flow detectors which are as fast, robust, and efficient as the ones found in biological systems is however a challenging task. Inspired by the architecture proposed by Barlow and Levick in 1965 to explain the spiking activity of the direction-selective ganglion cells in the rabbit's retina, we introduce an architecture for robust optical flow extraction with an analog neuromorphic multi-chip system. The task is performed by a feed-forward network of analog integrate-and-fire neurons whose inputs are provided by contrast-sensitive photoreceptors. Computation is supported by the precise time of spike emission, and the extraction of the optical flow is based on time lag in the activation of nearby retinal neurons. Mimicking ganglion cells our neuromorphic detectors encode the amplitude and the direction of the apparent visual motion in their output spiking pattern. Hereby we describe the architectural aspects, discuss its latency, scalability, and robustness properties and demonstrate that a network of mismatched delicate analog elements can reliably extract the optical flow from a simple visual scene. This work shows how precise time of spike emission used as a computational basis, biological inspiration, and neuromorphic systems can be used together for solving specific tasks. PMID:26909015

  12. The Bipolar Field-Effect Transistor: VII. The Unipolar Current Mode for Analog-RF Operation (Two-MOS-Gates on Pure-Base)

    International Nuclear Information System (INIS)

    This paper reports the DC steady-state current-voltage and conductance-voltage characteristics of a Bipolar Field-Effect Transistor (BiFET) under the unipolar (electron) current mode of operation, with bipolar (electron and hole) charge distributions considered. The model BiFET example presented has two MOS-gates on the two surfaces of a thin pure silicon base layer with electron and hole contacts on both edges of the thin base. The hole contacts on both edges of the thin pure base layer are grounded to give zero hole current. This 1-transistor analog-RF Basic Building Block nMOS amplifier circuit, operated in the unipolar current mode, complements the 1-transistor digital Basic Build Block CMOS voltage inverter circuit, operated in the bipolar-current mode just presented by us.

  13. The Bipolar Field-Effect Transistor:Ⅶ. The Unipolar Current Mode for Analog-RF Operation(Two-MOS-Gates on Pure-Base

    Institute of Scientific and Technical Information of China (English)

    Jie Binbin; Sah Chih-Tang

    2009-01-01

    This paper reports the DC steady-state current-voltage and conductance-voltage characteristics of a Bipolar Field-Effect Transistor (BiFET) under the unipolar (electron) current mode of operation, with bipolar (elec-tron and hole) charge distributions considered. The model BiFET example presented has two MOS-gates on the two surfaces of a thin pure silicon base layer with electron and hole contacts on both edges of the thin base. The hole contacts on both edges of the thin pure base layer are grounded to give zero hole current. This 1-transistor analog-RF Basic Building Block nMOS amplifier circuit, operated in the unipolar current mode, complements the 1-transistor digital Basic Build Block CMOS voltage inverter circuit, operated in the bipolar-current mode just presented by us.

  14. LANSCE-R WIRE-SCANNER ANALOG FRONT-END ELECTRONICS

    International Nuclear Information System (INIS)

    A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments Compact RIO (cRIO) module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal dataacquisition system, and wire bias of 0V to +/-50V. The AFE system is designed to accommodate comparatively long macropulses (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.

  15. Structure-based design of eugenol analogs as potential estrogen receptor antagonists.

    Science.gov (United States)

    Anita, Yulia; Radifar, Muhammad; Kardono, Leonardus Bs; Hanafi, Muhammad; Istyastono, Enade P

    2012-01-01

    Eugenol is an essential oil mainly found in the buds and leaves of clove (Syzygium aromaticum (L.) Merrill and Perry), which has been reported to have activity on inhibition of cell proliferation and apoptosis induction in human MCF-7 breast cancer cells. This biological activity is correlated to its activity as an estrogen receptor antagonist. In this article, we present the construction and validation of structure-based virtual screening (SBVS) protocols to identify the potent estrogen receptor α (ER) antagonists. The selected protocol, which gave acceptable enrichment factors as a virtual screening protocol, subsequently used to virtually screen eugenol, its analogs and their dimers. Based on the virtual screening results, dimer eugenol of 4-[4-hydroxy-3-(prop-2-en-1- yl)phenyl]-2-(prop-2-en-1-yl)phenol is recommended to be developed further in order to discover novel and potent ER antagonists. PMID:23144548

  16. Dietary nucleotides prevent decrease in cellular immunity in ground-based microgravity analog

    Science.gov (United States)

    Yamauchi, Keiko; Hales, Nathan W.; Robinson, Sandra M.; Niehoff, Michael L.; Ramesh, Vani; Pellis, Neal R.; Kulkarni, Anil D.

    2002-01-01

    Microgravity and stress of spaceflights result in immune dysfunction. The role of nutrition, especially nucleotide supplementation, has become an area of intensive research and significant interest in immunomodulation for maintenance of cellular immune responses. The studies presented here evaluate the plausibility of administering nucleotides to obviate immune dysfunction in an Earth-based in vivo analog of microgravity as studied in anti-orthostatic tail suspension (AOS) of mice. Mice were divided into three housing groups: group, isolation, and AOS. Mice were fed either control chow diet (CD), or RNA-, adenine-, or uracil-supplemented CD for the 1-wk duration of the experiments. In AOS mice, supplemental nucleotides significantly increased in vivo lymph node proliferation and ex vivo lymphoproliferation response to alloantigen and mitogens, respectively, and interleukin-2 and interferon-gamma production. A lower corticosterone level was observed in uracil-supplemented CD compared with CD. These results suggest that exogenous nucleotide supplementation, especially uracil, of normal diet is beneficial in the maintenance and restoration of the immune response during the microgravity analog conditions.

  17. Is neoclassical microeconomics formally valid? An approach based on an analogy with equilibrium thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Tania; Domingos, Tiago [Environment and Energy Section, DEM, Instituto Superior Tecnico, Avenida Rovisco Pais, 1, 1049-001 Lisboa (Portugal)

    2006-06-10

    The relation between Thermodynamics and Economics is a paramount issue in Ecological Economics. Two different levels can be distinguished when discussing it: formal and substantive. At the formal level, a mathematical framework is used to describe both thermodynamic and economic systems. At the substantive level, thermodynamic laws are applied to economic processes. In Ecological Economics, there is a widespread claim that neoclassical economics has the same mathematical formulation as classical mechanics and is therefore fundamentally flawed because: (1) utility does not obey a conservation law as energy does; (2) an equilibrium theory cannot be used to study irreversible processes. Here, we show that neoclassical economics is based on a wrong formulation of classical mechanics, being in fact formally analogous to equilibrium thermodynamics. The similarity between both formalisms, namely that they are both cases of constrained optimisation, is easily perceived when thermodynamics is looked upon using the Tisza-Callen axiomatisation. In this paper, we take the formal analogy between equilibrium thermodynamics and economic systems far enough to answer the formal criticisms, proving that the formalism of neoclassical economics has irreversibility embedded in it. However, the formal similarity between equilibrium thermodynamics and neoclassical microeconomics does not mean that economic models are in accordance with mass, energy and entropy balance equations. In fact, neoclassical theory suffers from flaws in the substantive integration with thermodynamic laws as has already been fully demonstrated by valuable work done by ecological economists in this field. (author)

  18. Automatic calibration system for analog instruments based on DSP and CCD sensor

    Science.gov (United States)

    Lan, Jinhui; Wei, Xiangqin; Bai, Zhenlong

    2008-12-01

    Currently, the calibration work of analog measurement instruments is mainly completed by manual and there are many problems waiting for being solved. In this paper, an automatic calibration system (ACS) based on Digital Signal Processor (DSP) and Charge Coupled Device (CCD) sensor is developed and a real-time calibration algorithm is presented. In the ACS, TI DM643 DSP processes the data received by CCD sensor and the outcome is displayed on Liquid Crystal Display (LCD) screen. For the algorithm, pointer region is firstly extracted for improving calibration speed. And then a math model of the pointer is built to thin the pointer and determine the instrument's reading. Through numbers of experiments, the time of once reading is no more than 20 milliseconds while it needs several seconds if it is done manually. At the same time, the error of the instrument's reading satisfies the request of the instruments. It is proven that the automatic calibration system can effectively accomplish the calibration work of the analog measurement instruments.

  19. Small Molecule AngIV-based Analogs to Treat Alzheimers Disease

    Directory of Open Access Journals (Sweden)

    John W Wright

    2016-06-01

    Full Text Available Alzheimer’s disease (AD patients are presently without adequate treatment thus new therapeutic approaches are needed to slow and hopefully reverse disease progression. Neurotrophic agents such as nerve growth factor and brain-derived neurotrophic factor have received research attention concerning their potential to treat AD but have not progressed to clinical trials due to their large size, inability to penetrate the blood-brain barrier (BBB, and the high cost of synthesis. This review focuses on one over looked neurotrophin, hepatocyte growth factor (HGF that acts via the Type 1 tyrosine kinase receptor Met to mediate stem cell differentiation, synaptogenesis, neurogenesis, and protect against tissue insults in a wide range of cell types including neurons. We have determined that the brain angiotensin and HGF/c-Met systems interact in such a way that angiotensin IV (AngIV-based analogs including Nle1-AngIV, Norleual-AngIV, Dihexa, and others influence HGF dimerization which is a prerequisite to binding at the Met receptor. Several of these analogs have shown the ability to facilitate the formation of new functional synaptic connections in hippocampal slices, promote neurogenesis, and augment memory consolidation and retrieval in animal models of AD. This family of compounds represents a new class of drugs with lead candidates that are orally active, penetrate the BBB sufficiently to reach therapeutic concentrations, and reverse memory deficits seen in animal models of dementia.

  20. Design and synthesis of simplified taxol analogs based on the T-Taxol bioactive conformation

    OpenAIRE

    Zhao, Jielu; Bane, Susan; Snyder, James P.; Hu, Haipeng; Mukherjee, Kamalika; Slebodnick, Carla; Kingston, David G I

    2011-01-01

    A series of compounds designed to adopt a conformation similar to the tubulin-binding T-Taxol conformation of the anticancer drug paclitaxel has been synthesized. Both the internally bridged analogs 37-39, 41 and the open-chain analogs 27-29 and 43 were prepared. The bridged analogs 37-39 and 41 were synthesized by Grubbs' metatheses of compounds 30-32 and 33, which, in turn, were prepared by coupling β-lactams 24-26 with alcohols 22 and 23. Both the bridged and the open-chain analogs showed ...

  1. The Effects of Trivalent Lanthanide Cationization on the Electron Transfer Dissociation of Acidic Fibrinopeptide B and its Analogs

    Science.gov (United States)

    Commodore, Juliette J.; Cassady, Carolyn J.

    2016-06-01

    Electrospray ionization (ESI) on mixtures of acidic fibrinopeptide B and two peptide analogs with trivalent lanthanide salts generates [M + Met + H]4+, [M + Met]3+, and [M + Met -H]2+, where M = peptide and Met = metal (except radioactive promethium). These ions undergo extensive and highly efficient electron transfer dissociation (ETD) to form metallated and non-metallated c- and z-ions. All metal adducted product ions contain at least two acidic sites, which suggest attachment of the lanthanide cation at the side chains of one or more acidic residues. The three peptides undergo similar fragmentation. ETD on [M + Met + H]4+ leads to cleavage at every residue; the presence of both a metal ion and an extra proton is very effective in promoting sequence-informative fragmentation. Backbone dissociation of [M + Met]3+ is also extensive, although cleavage does not always occur between adjacent glutamic acid residues. For [M + Met - H ]2+, a more limited range of product ions form. All lanthanide metal peptide complexes display similar fragmentation except for europium (Eu). ETD on [M + Eu - H]2+ and [M + Eu]3+ yields a limited amount of peptide backbone cleavage; however, [M + Eu + H]4+ dissociates extensively with cleavage at every residue. With the exception of the results for Eu(III), metallated peptide ion formation by ESI, ETD fragmentation efficiencies, and product ion formation are unaffected by the identity of the lanthanide cation. Adduction with trivalent lanthanide metal ions is a promising tool for sequence analysis of acidic peptides by ETD.

  2. Modern approaches to the design of analog-digit integrated circuits based on multilevel simulation methods

    International Nuclear Information System (INIS)

    Modern methods for the design of analog and analog-digit integrated circuits have been analyzed. “Top-down” and “bottom-up” design methods are compared. The advantages of the “top-down” method in the rate of the development and verification of integrated circuits have been demonstrated

  3. Response matrix Monte Carlo based on a general geometry local calculation for electron transport

    International Nuclear Information System (INIS)

    A Response Matrix Monte Carlo (RMMC) method has been developed for solving electron transport problems. This method was born of the need to have a reliable, computationally efficient transport method for low energy electrons (below a few hundred keV) in all materials. Today, condensed history methods are used which reduce the computation time by modeling the combined effect of many collisions but fail at low energy because of the assumptions required to characterize the electron scattering. Analog Monte Carlo simulations are prohibitively expensive since electrons undergo coulombic scattering with little state change after a collision. The RMMC method attempts to combine the accuracy of an analog Monte Carlo simulation with the speed of the condensed history methods. Like condensed history, the RMMC method uses probability distributions functions (PDFs) to describe the energy and direction of the electron after several collisions. However, unlike the condensed history method the PDFs are based on an analog Monte Carlo simulation over a small region. Condensed history theories require assumptions about the electron scattering to derive the PDFs for direction and energy. Thus the RMMC method samples from PDFs which more accurately represent the electron random walk. Results show good agreement between the RMMC method and analog Monte Carlo. 13 refs., 8 figs

  4. Automatic generation of analogy questions for student assessment: an Ontology-based approach

    Directory of Open Access Journals (Sweden)

    Bijan Parsia

    2012-08-01

    Full Text Available Different computational models for generating analogies of the form “A is to B as C is to D” have been proposed over the past 35 years. However, analogy generation is a challenging problem that requires further research. In this article, we present a new approach for generating analogies in Multiple Choice Question (MCQ format that can be used for students’ assessment. We propose to use existing high-quality ontologies as a source for mining analogies to avoid the classic problem of hand-coding concepts in previous methods. We also describe the characteristics of a good analogy question and report on experiments carried out to evaluate the new approach.

  5. Modular Hybrid Energy Concept Employing a Novel Control Structure Based on a Simple Analog System

    Directory of Open Access Journals (Sweden)

    PETREUS, D.

    2016-05-01

    Full Text Available This paper proposes a novel control topology which enables the setup of a low cost analog system leading to the implementation of a modular energy conversion system. The modular concept is based on hybrid renewable energy (solar and wind and uses high voltage inverters already available on the market. An important feature of the proposed topology is a permanently active current loop, which assures short circuit protection and simplifies the control loops compensation. The innovative analogue solution of the control structure is based on a dedicated integrated circuit (IC for power factor correction (PFC circuits, used in a new configuration, to assure an efficient inverter start-up. The energy conversion system (control structure and maximum power point tracking algorithm is simulated using a new macromodel-based concept, which reduces the usual computational burden of the simulator and achieves high processing speed. The proposed novel system is presented in this article from concept, through the design and implementation stages, is verified through simulation and is validated by experimental results.

  6. Analog optical computing based on a dielectric meta-reflect array.

    Science.gov (United States)

    Chizari, Ata; Abdollahramezani, Sajjad; Jamali, Mohammad Vahid; Salehi, Jawad A

    2016-08-01

    In this Letter, we realize the concept of analog computing using an engineered gradient dielectric meta-reflect-array. The proposed configuration consists of individual subwavelength silicon nanobricks, in combination with a fused silica spacer and silver ground plane, realizing a reflection beam with full phase coverage of 2π degrees, as well as an amplitude range of 0 to 1. Spectrally overlapping electric and magnetic dipole resonances, such high-index dielectric metasurfaces can locally and independently manipulate the amplitude and phase of the incident electromagnetic wave. This practically feasible structure overcomes substantial limitations imposed by plasmonic metasurfaces such as absorption losses and low polarization conversion efficiency in the visible range. Using such CMOS-compatible and easily integrable platforms promises highly efficient ultrathin planar wave-based computing systems that circumvent the drawbacks of conventional bulky lens-based signal processors. Based on these key properties and the general concept of spatial Fourier transformation, we design and realize broadband mathematical operators such as the differentiator and integrator in the telecommunication wavelengths. PMID:27472591

  7. SPIROC: design and performances of a dedicated very front-end electronics for an ILC Analog Hadronic CALorimeter (AHCAL) prototype with SiPM read-out

    International Nuclear Information System (INIS)

    For the future e+ e- International Linear Collider (ILC) the ASIC SPIROC (Silicon Photomultiplier Integrated Read-Out Chip) was designed to read out the Analog Hadronic Calorimeter (AHCAL) equipped with Silicon Photomultiplier (SiPM). It is an evolution of the FLCSiPM chip designed by the OMEGA group in 2005. SPIROC2 [1] was realized in AMS SiGe 0.35 μm technology [2] and developed to match the requirements of large dynamic range, low noise, low consumption, high precision and large number of read-out channels. This ASIC is a very front-end read-out chip that integrates 36 self triggered channels with variable gain to achieve charge and time measurements. The charge measurement must be performed from 1 up to 2000 photo-electrons (p.e.) corresponding to 160 fC up to 320 pC for SiPM gain 106. The time measurement is performed with a coarse 12-bit counter related to the bunch crossing clock (up to 5 MHz) and a fine time ramp based on this clock (down to 200 ns) to achieve a resolution of 1 ns. An analog memory array with a depth of 16 for each channel is used to store the time information and the charge measurement. The analog memory content (time and charge) is digitized thanks to an internal 12-bit Wilkinson ADC. The data is then stored in a 4kbytes RAM. A complex digital part is necessary to manage all these features and to transfer the data to the DAQ. SPIROC2 is the second generation of the SPIROC ASIC family designed in 2008 by the OMEGA group. A very similar version (SPIROC2c) was submitted in February 2012 to improve the noise performance and also to integrate a new TDC (Time to Digital Converter) structure. This paper describes SPIROC2 and SPIROC2c ASICs and illustrates the main characteristics thank to a series of measurements.

  8. In-line polarization rotator based on the quantum-optical analogy.

    Science.gov (United States)

    Chen, Lei; Qu, Ke-Nan; Shen, Heng; Zhang, Wei-Gang; Chou, Keng C; Liu, Qian; Yan, Tie-Yi; Wang, Biao; Wang, Song

    2016-05-01

    An in-line polarization rotator (PR) is proposed based on the quantum-optical analogy (QOA). The proposed PR possesses an auxiliary E7 liquid crystal (LC) waveguide in the vicinity of the single-mode fiber (SMF) core. Because of the matched core size, the PR demonstrates good compatibility with the established backbone networks which are composed of conventional SMFs. With optimized parameters for the auxiliary waveguide, the PR offers a near 100% polarization conversion efficiency at the 1550 nm band with a bandwidth of ∼30  nm, a length of ∼4625.9  μm with a large tolerance of ∼550  μm, and a tolerance of the input light polarization angle and rotation angle of the E7 LC of ∼π/30 and ∼π/36  rad, respectively. The performance was verified by the full-vector finite-element method. The proposed PR can be easily fabricated based on the existing photonics crystal fiber manufacturing process, making it a potentially inexpensive device for applications in modern communication systems. Moreover, the QOA, compared with the previous supermode-theory design method, allows a designer to consider several waveguides separately. Therefore, various unique characteristics can be met simultaneously which is consistent with the trend of modern fiber design. PMID:27128087

  9. Supporting Analogy-based Effort Estimation with the Use of Ontologies

    Directory of Open Access Journals (Sweden)

    Joanna Kowalska

    2014-06-01

    Full Text Available The paper concerns effort estimation of software development projects, in particular, at the level of product delivery stages. It proposes a new approach to model project data to support expert-supervised analogy-based effort estimation. The data is modeled using Semantic Web technologies, such as Resource Description Framework (RDF and Ontology Language for the Web (OWL. Moreover, in the paper, we define a method of supervised case-based reasoning. The method enables to search for similar projects’ tasks at different levels of abstraction. For instance, instead of searching for a task performed by a specific person, one could look for tasks performed by people with similar capabilities. The proposed method relies on ontology that defines the core concepts and relationships. However, it is possible to introduce new classes and relationships, without the need of altering the search mechanisms. Finally, we implemented a prototype tool that was used to preliminary validate the proposed approach. We observed that the proposed approach could potentially help experts in estimating non-trivial tasks that are often underestimated.

  10. Synthesis and anti-HBV activity of α-stereoisomer of aristeromycin based analogs.

    Science.gov (United States)

    Kasula, Mohan; Toyama, Masaaki; Samunuri, Ramakrishnamraju; Rozy, Farhana; Yadav, Monika; Bal, Chandralata; Jha, Ashok Kumar; Baba, Masanori; Sharon, Ashoke

    2016-08-15

    The potential antiviral activity of aristeromycin type of derivatives (I) is limited by associated toxicity due to its possible 5'-O-phosphorylation and S-adenosyl-l-homocysteine hydrolase (SAHase) inhibitory activity. Aristeromycin structure has major pharmacophoric motif as 5'-OH and adenosine base, which may have significant role in enzyme binding followed by activity and or toxicity. Thus, the structural optimization to alter this major motif by replacing with its bioisostere and changing the 5'-O conformation through stereochemistry reversal was of interest. Thus, the inverted stereochemistry at 4'-position coupled with bioisostere of adenosine base in the target compounds (6-7) to access antiviral potential. The stereoselective formation of a key stereoisomer (2a) was achieved exclusively from neplanocin sugar (1a) by reduction in a single step. The novel target molecules (6-7) were synthesized in 4 steps with 55-62% yield. Compound 6 was analyzed by single crystal X-ray diffraction, which confirms the stereoselective formation of α-analogs with highly puckered cyclopentane ring and 2'-endo conformation. The compound 6 shown significant anti-hepatitis B virus activity of 6.5μM with CC50>100μM and yielded a promising lead with novel structural feature. PMID:27426303

  11. Quantum theory of magnetic electron lenses based on the Dirac equation.

    OpenAIRE

    Jagannathan, R.; Simon, R.; Sudarshan, ECG; Mukunda, N.

    1989-01-01

    A quantum theory of magnetic electron lenses based on a convenient formulation of the Dirac theory is outlined. It is shown that the passage from the conventional scalar theory to the spinor theory can be accomplished through a simple algebraic rule in analogy with the passage from scalar to vector light optics.

  12. Synthesis of Novel Homo-N-Nucleoside Analogs Composed of a Homo-1,4-Dioxane Sugar Analog and Substituted 1,3,5-Triazine Base Equivalents

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    2008-12-01

    Full Text Available Enantioselective syntheses from dimethyl tartrate of 1,3,5-triazine homo-N-nucleoside analogs, containing a 1,4-dioxane moiety replacing the sugar unit in natural nucleosides, were accomplished. The triazine heterocycle in the nucleoside analogs was further substituted with combinations of NH2, OH and Cl in the 2,4-triazine positions.

  13. Click-based synthesis of bromotyrosine alkaloid analogs as potential anti-biofilm leads for SAR studies.

    Science.gov (United States)

    Andjouh, S; Blache, Y

    2015-12-15

    A library of triazole-based analogs of bromotyramine alkaloids such as verongamines, hemibastadins, pseudoceramine D and clavatidine E was designed in order to identify promising leads that may help in the control of bacterial biofilms. Twenty-three compounds were screened for their biofilm inhibitory activity against three strains of Gram-negative bacteria. SAR studies revealed that hemibastadins analogs were the most active compounds which act as inhibitors of biofilm development (EC50 8.8-29μM) without effect on bacterial growth even at high concentrations (100μM). PMID:26564265

  14. A Fault Dictionary-Based Fault Diagnosis Approach for CMOS Analog Integrated Circuits

    Directory of Open Access Journals (Sweden)

    Mouna Karmani

    2011-10-01

    Full Text Available In this paper, we propose a simulation-before-test (SBT fault diagnosis methodology based on the use of afault dictionary approach. This technique allows the detection and localization of the most likely defects ofopen-circuit type occurring in Complementary Metal–Oxide–Semiconductor (CMOS analog integratedcircuits (ICs interconnects. The fault dictionary is built by simulating the most likely defects causing thefaults to be detected at the layout level. Then, for each injected fault, the spectre’s frequency responses andthe power consumption obtained by simulation are stored in a table which constitutes the fault dictionary.In fact, each line in the fault dictionary constitutes a fault signature used to identify and locate aconsidered defect. When testing, the circuit under test is excited with the same stimulus, and the responsesobtained are compared to the stored ones. To prove the efficiency of the proposed technique, a full customCMOS operational amplifier is implemented in 0.25 μm technology and the most likely faults of opencircuittype are deliberately injected and simulated at the layout level.

  15. Creating analogs of thermal distributions from diabatic excitations in ion-trap-based quantum simulation

    Science.gov (United States)

    Lim, M. H.; Yoshimura, B. T.; Freericks, J. K.

    2016-04-01

    One broad goal of quantum simulation is to start a simple quantum system in its ground state and slowly evolve the Hamiltonian to a complex one, maintaining the ground state throughout the evolution (called adiabatic state preparation). This provides a natural setting to create a highly entangled and correlated quantum state if the final Hamiltonian supports such a ground state. In ion-trap-based quantum simulations, coherence times are too short to allow for such ground-state evolution for large chains, because the rapid evolution of the system creates excitations to higher energy states. Because the probability for this excitation depends exponentially on the excitation energy and because the thermal distribution also depends exponentially on the excitation energy, we investigate whether this so-called diabatic excitation can create the analog of a thermal distribution; as this could serve as an alternative for creating thermal states of complex quantum systems without requiring contact with a heat bath. In this work, we explore this relationship and determine situations, where diabatic excitation can approximately create thermal states.

  16. Experiments on Evolving Software Models of Analog Circuits

    Science.gov (United States)

    Lohn, Jason D.

    1999-01-01

    Analog circuits are of great importance in electronic system design since the world is fundamentally analog in nature. While the amount of digital design activity far outpaces that of analog design, most digital systems require analog modules for interfacing with the external world. It was recently estimated that approximately 60% of digital application- specific integrated circuit designs incorporated analog circuits. With challenging analog circuit design problems and few analog design engineers, there are economic reasons for automating the analog design process, especially time-to-market considerations. Techniques for analog circuit design automation began appearing about two decades ago. These methods incorporated heuristics [6], knowledge bases [1], simulated annealing [5], and other algorithms. Efforts using techniques from evolutionary computation began appearing over the last few years. These include the use of genetic algorithms to select electronic component values (for example, the resistance value of a resistor), to select circuit topologies, and to design amplifiers using a limited set of canned topologies [4]. A genetic programming-based analog circuit design system has been demonstrated in which the circuit sizes, component values, and the circuit topologies are determined automatically [3]. The genetic-algorithm systems typically represent circuit structures as vectors of parameters encoded in binary strings, while the genetic programming system manipulates tree data structures.

  17. Electronic structure of. pi. systems. II. Photoelectron spectra and occupied orbitals of some. pi. donors which are derivatives and analogs of bipyranylidene

    Energy Technology Data Exchange (ETDEWEB)

    Traven' , V.F.; Martirosyan, M.A.; Redchenko, V.V.; Chibisova, T.A.

    1987-08-20

    Quantum-chemical calculations by a simple method (parametrization based on data from photoelectron spectroscopy) objectively reproduce the structure of the occupied ..pi.. molecular orbitals of ..pi.. donors of the bichalcogenapyranylidene and tetrachalcogenafulvalene series. The occupied ..pi.. molecular orbitals of the bichalcogenapyranylidenes have the same order as do the orbitals of the tetrachalcogenafulvalenes, but they have smaller contributions from the AO's of the heteroatoms: 3b/sub 1u/, 2b/sub 2g/, 1a/sub 1u/, 1b/sub 3g/, 2b/sub 1u/, 1b/sub 2g/, 1b/sub 1u/. The first ionization potentials of the bichalcogenapoyranylidenes are somewhat lower than those of the analogous tetrachalcogenafulvalenes, but the second ionization potentials are considerably higher. As the atomic number of the chalcogen is increased, the occupied molecular orbitals approach each other to an appreciable extent in the series of bichalcogenapyranylidenes. In tetraphenylbichalcogenapyranylidenes there are electronic levels which are delocalized over the entire molecule.

  18. The Age of Analog Networks

    OpenAIRE

    Mattiussi, Claudio; Swiss Federal Institute of Technology in Lausanne (EPFL); Marbach, Daniel; Swiss Federal Institute of Technology in Lausanne (EPFL); Dürr, Peter; Swiss Federal Institute of Technology in Lausanne (EPFL); Floreano, Dario; Swiss Federal Institute of Technology in Lausanne (EPFL)

    2008-01-01

    A large class of systems of biological and technological relevance can be described as analog networks, that is, collections of dynamical devices interconnected by links of varying strength. Some examples of analog networks are genetic regulatory networks, metabolic networks, neural networks, analog electronic circuits, and control systems. Analog networks are typically complex systems which include nonlinear feedback loops and possess temporal dynamics at different timescales. When tackled b...

  19. A reuse-based framework for the design of analog and mixed-signal ICs

    Science.gov (United States)

    Castro-Lopez, Rafael; Fernandez, Francisco V.; Rodriguez Vazquez, Angel

    2005-06-01

    Despite the spectacular breakthroughs of the semiconductor industry, the ability to design integrated circuits (ICs) under stringent time-to-market (TTM) requirements is lagging behind integration capacity, so far keeping pace with still valid Moore"s Law. The resulting gap is threatening with slowing down such a phenomenal growth. The design community believes that it is only by means of powerful CAD tools and design methodologies - and, possibly, a design paradigm shift - that this design gap can be bridged. In this sense, reuse-based design is seen as a promising solution, and concepts such as IP Block, Virtual Component, and Design Reuse have become commonplace thanks to the significant advances in the digital arena. Unfortunately, the very nature of analog and mixed-signal (AMS) design has hindered a similar level of consensus and development. This paper presents a framework for the reuse-based design of AMS circuits. The framework is founded on three key elements: (1) a CAD-supported hierarchical design flow that facilitates the incorporation of AMS reusable blocks, reduces the overall design time, and expedites the management of increasing AMS design complexity; (2) a complete, clear definition of the AMS reusable block, structured into three separate facets or views: the behavioral, structural, and layout facets, the two first for top-down electrical synthesis and bottom-up verification, the latter used during bottom-up physical synthesis; (3) the design for reusability set of tools, methods, and guidelines that, relying on intensive parameterization as well as on design knowledge capture and encapsulation, allows to produce fully reusable AMS blocks. A case study and a functional silicon prototype demonstrate the validity of the paper"s proposals.

  20. Model, analysis, and evaluation of the effects of analog VLSI arithmetic on linear subspace-based image recognition.

    Science.gov (United States)

    Carvajal, Gonzalo; Figueroa, Miguel

    2014-07-01

    Typical image recognition systems operate in two stages: feature extraction to reduce the dimensionality of the input space, and classification based on the extracted features. Analog Very Large Scale Integration (VLSI) is an attractive technology to achieve compact and low-power implementations of these computationally intensive tasks for portable embedded devices. However, device mismatch limits the resolution of the circuits fabricated with this technology. Traditional layout techniques to reduce the mismatch aim to increase the resolution at the transistor level, without considering the intended application. Relating mismatch parameters to specific effects in the application level would allow designers to apply focalized mismatch compensation techniques according to predefined performance/cost tradeoffs. This paper models, analyzes, and evaluates the effects of mismatched analog arithmetic in both feature extraction and classification circuits. For the feature extraction, we propose analog adaptive linear combiners with on-chip learning for both Least Mean Square (LMS) and Generalized Hebbian Algorithm (GHA). Using mathematical abstractions of analog circuits, we identify mismatch parameters that are naturally compensated during the learning process, and propose cost-effective guidelines to reduce the effect of the rest. For the classification, we derive analog models for the circuits necessary to implement Nearest Neighbor (NN) approach and Radial Basis Function (RBF) networks, and use them to emulate analog classifiers with standard databases of face and hand-writing digits. Formal analysis and experiments show how we can exploit adaptive structures and properties of the input space to compensate the effects of device mismatch at the application level, thus reducing the design overhead of traditional layout techniques. Results are also directly extensible to multiple application domains using linear subspace methods. PMID:24732237

  1. Efficient and accurate statistical analog yield optimization and variation-aware circuit sizing based on computational intelligence techniques

    OpenAIRE

    Liu, Bo; Fernández, Francisco V.; Gielen, Georges

    2011-01-01

    In nanometer complementary metal-oxide-semiconductor technologies, worst-case design methods and response-surface-based yield optimization methods face challenges in accuracy. Monte-Carlo (MC) simulation is general and accurate for yield estimation, but its efficiency is not high enough to make MC-based analog yield optimization, which requires many yield estimations, practical. In this paper, techniques inspired by computational intelligence are used to speed up yield optimization without sa...

  2. Zero-Gravity Locomotion Simulators: New Ground-Based Analogs for Microgravity Exercise Simulation

    Science.gov (United States)

    Perusek, Gail P.; DeWitt, John K.; Cavanagh, Peter R.; Grodsinsky, Carlos M.; Gilkey, Kelly M.

    2007-01-01

    Maintaining health and fitness in crewmembers during space missions is essential for preserving performance for mission-critical tasks. NASA's Exercise Countermeasures Project (ECP) provides space exploration exercise hardware and monitoring requirements that lead to devices that are reliable, meet medical, vehicle, and habitat constraints, and use minimal vehicle and crew resources. ECP will also develop and validate efficient exercise prescriptions that minimize daily time needed for completion of exercise yet maximize performance for mission activities. In meeting these mission goals, NASA Glenn Research Center (Cleveland, OH, USA), in collaboration with the Cleveland Clinic (Cleveland, Ohio, USA), has developed a suite of zero-gravity locomotion simulators and associated technologies to address the need for ground-based test analog capability for simulating in-flight (microgravity) and surface (partial-gravity) exercise to advance the health and safety of astronaut crews and the next generation of space explorers. Various research areas can be explored. These include improving crew comfort during exercise, and understanding joint kinematics and muscle activation pattern differences relative to external loading mechanisms. In addition, exercise protocol and hardware optimization can be investigated, along with characterizing system dynamic response and the physiological demand associated with advanced exercise device concepts and performance of critical mission tasks for Exploration class missions. Three zero-gravity locomotion simulators are currently in use and the research focus for each will be presented. All of the devices are based on a supine subject suspension system, which simulates a reduced gravity environment by completely or partially offloading the weight of the exercising test subject s body. A platform for mounting treadmill is positioned perpendicularly to the test subject. The Cleveland Clinic Zero-g Locomotion Simulator (ZLS) utilizes a

  3. Advances in Analog Circuit Design 2015

    CERN Document Server

    Baschirotto, Andrea; Harpe, Pieter

    2016-01-01

    This book is based on the 18 tutorials presented during the 24th workshop on Advances in Analog Circuit Design. Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including low-power and energy-efficient analog electronics, with specific contributions focusing on the design of efficient sensor interfaces and low-power RF systems. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development. ·         Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; ·         Presents material in a tutorial-based format; ·         Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing.

  4. Flexible Analog Front Ends of Reconfigurable Radios Based on Sampling and Reconstruction with Internal Filtering

    Directory of Open Access Journals (Sweden)

    Poberezhskiy Gennady Y

    2005-01-01

    Full Text Available Bandpass sampling, reconstruction, and antialiasing filtering in analog front ends potentially provide the best performance of software defined radios. However, conventional techniques used for these procedures limit reconfigurability and adaptivity of the radios, complicate integrated circuit implementation, and preclude achieving potential performance. Novel sampling and reconstruction techniques with internal filtering eliminate these drawbacks and provide many additional advantages. Several ways to overcome the challenges of practical realization and implementation of these techniques are proposed and analyzed. The impact of sampling and reconstruction with internal filtering on the analog front end architectures and capabilities of software defined radios is discussed.

  5. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  6. Interferon Analogs

    NARCIS (Netherlands)

    Poelstra, Klaas; Prakash, Jai; Beljaars, Eleonora; Bansal, Ruchi

    2015-01-01

    The invention relates to the field of medicine. Among others, it relates to biologically active analogs of interferons (IFNs) which show less unwanted side-effects and to the therapeutic uses thereof. Provided is an IFN analog, wherein the moiety mediating binding to its natural receptor is at least

  7. Interferon Analogs

    NARCIS (Netherlands)

    Poelstra, Klaas; Prakash, Jai; Beljaars, Leonie; Bansal, Ruchi

    2010-01-01

    The invention relates to the field of medicine. Among others, it relates to biologically active analogs of interferons (IFNs) which show less unwanted side-effects and to the therapeutic uses thereof. Provided is an IFN analog, wherein the moiety mediating binding to its natural receptor is at least

  8. Nucleic Acid Base Analog FRET-Pair Facilitating Detailed Structural Measurements in Nucleic Acid Containing Systems

    DEFF Research Database (Denmark)

    Börjesson, Karl; Preus, Søren; El-Sagheer, Afaf;

    2009-01-01

    We present the first nucleobase analog fluorescence resonance energy transfer (FRET)-pair. The pair consists of tCO, 1,3-diaza-2-oxophenoxazine, as an energy donor and the newly developed tC(nitro), 7-nitro-1,3-diaza-2-oxophenothiazine, as an energy acceptor. The FRET-pair successfully monitors d...

  9. Detecting lung cancer symptoms with analogic CNN algorithms based on a constrained diffusion template

    International Nuclear Information System (INIS)

    In this article, a new type of diffusion template and an analogic CNN algorithm using this diffusion template for detecting some lung cancer symptoms in X-ray films are proposed. The performance of the diffusion template is investigated and our CNN algorithm is verified to detect some key lung cancer symptoms, successfully. (author)

  10. Electronic Seal Stamping Based on Group Signature

    OpenAIRE

    Girija Srikanth

    2011-01-01

    This paper describes a new electronic official seal stamping based on Group Signature, USB Key. Bill/Contract in E-commerce must be seal stamped to gain tamper proof and non-repudiation. The seal stamping control is designed based on the certificate-based public key. This technique is more efficient for generating and verifying individual/group signatures in terms of computational efforts and communication costs. Web page electronic seal-stamping system is implemented which has been adopted b...

  11. Characterization of front-end electronics for CZT based handheld radioisotope identifier

    Energy Technology Data Exchange (ETDEWEB)

    Lombigit, L., E-mail: lojius@nm.gov.my [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahman, Nur Aira Abd; Mohamad, Glam Hadzir Patai; Ibrahim, Maslina Mohd; Yussup, Nolida; Yazid, Khairiah; Jaafar, Zainudin

    2016-01-22

    A radioisotope identifier device based on large volume Co-planar grid CZT detector is current under development at Malaysian Nuclear Agency. This device is planned to be used for in-situ identification of radioisotopes based on their unique energies. This work reports on electronics testing performed on the front-end electronics (FEE) analog section comprising charge sensitive preamplifier-pulse shaping amplifier chain. This test involves measurement of charge sensitivity, pulse parameters and electronics noise. This report also present some preliminary results on the spectral measurement obtained from gamma emitting radioisotopes.

  12. Genome-wide screening for genes whose deletions confer sensitivity to mutagenic purine base analogs in yeast

    Directory of Open Access Journals (Sweden)

    Kozmin Stanislav G

    2005-06-01

    Full Text Available Abstract Background N-hydroxylated base analogs, such as 6-hydroxylaminopurine (HAP and 2-amino-6-hydroxylaminopurine (AHA, are strong mutagens in various organisms due to their ambiguous base-pairing properties. The systems protecting cells from HAP and related noncanonical purines in Escherichia coli include specialized deoxyribonucleoside triphosphatase RdgB, DNA repair endonuclease V, and a molybdenum cofactor-dependent system. Fewer HAP-detoxification systems have been identified in yeast Saccharomyces cerevisiae and other eukaryotes. Cellular systems protecting from AHA are unknown. In the present study, we performed a genome-wide search for genes whose deletions confer sensitivity to HAP and AHA in yeast. Results We screened the library of yeast deletion mutants for sensitivity to the toxic and mutagenic action of HAP and AHA. We identified novel genes involved in the genetic control of base analogs sensitivity, including genes controlling purine metabolism, cytoskeleton organization, and amino acid metabolism. Conclusion We developed a method for screening the yeast deletion library for sensitivity to the mutagenic and toxic action of base analogs and identified 16 novel genes controlling pathways of protection from HAP. Three of them also protect from AHA.

  13. Biomaterials-Based Organic Electronic Devices

    Science.gov (United States)

    Bettinger, Christopher J.; Bao, Zhenan

    2010-01-01

    Organic electronic devices have demonstrated tremendous versatility in a wide range of applications including consumer electronics, photovoltaics, and biotechnology. The traditional interface of organic electronics with biology, biotechnology, and medicine occurs in the general field of sensing biological phenomena. For example, the fabrication of hybrid electronic structures using both organic semiconductors and bioactive molecules has led to enhancements in sensitivity and specificity within biosensing platforms, which in turn has a potentially wide range of clinical applications. However, the interface of biomolecules and organic semiconductors has also recently explored the potential use of natural and synthetic biomaterials as structural components of electronic devices. The fabrication of electronically active systems using biomaterials-based components has the potential to realize a large set of unique devices including environmentally biodegradable systems and bioresorbable temporary medical devices. This article reviews recent advances in the implementation of biomaterials as structural components in organic electronic devices with a focus on potential applications in biotechnology and medicine. PMID:20607127

  14. A Physical Analog Model of Strike-Slip Faulting for Model-Based Inquiry in the Classroom

    Science.gov (United States)

    Curren, I. S.; Glesener, G.

    2013-12-01

    classroom setting. We hope to encourage discussion from session attendees on the use of physical analog models and real-time quantitative model-based inquiry in the development of the next generation of geoscientists.

  15. Superconductivity in SnO: A Nonmagnetic Analog to Fe-Based Superconductors?

    DEFF Research Database (Denmark)

    Forthaus, M. K.; Sengupta, K.; Heyer, O.;

    2010-01-01

    We discovered that under pressure SnO with α-PbO structure, the same structure as in many Fe-based superconductors, e.g., β-FeSe, undergoes a transition to a superconducting state for p≳6  GPa with a maximum Tc of 1.4 K at p=9.3  GPa. The pressure dependence of Tc reveals a domelike shape...... and superconductivity disappears for p≳16  GPa. It is further shown from band structure calculations that SnO under pressure exhibits a Fermi surface topology similar to that reported for some Fe-based superconductors and that the nesting between the hole and electron pockets correlates with the change of Tc...

  16. A mixed analog-digital radiation hard technology for high energy physics electronics DMILL (Durci Mixte sur Isolant Logico-Linéaire)

    CERN Document Server

    Beuville, E; Borgeaud, P; Fourches, N T; Rouger, M; Blanc, J P; Bruel, M; Delevoye-Orsier, E; Gautier, J; Du Port de Pontcharra, J; Truche, R; Dupont-Nivet, E; Flament, O; Leray, J L; Martin, J L; Montaron, J; Borel, G; Brice, J M; Chatagnon, P; Terrier, C; Aubert, Jean-Jacques; Delpierre, P A; Habrard, M C; Potheau, R; CERN. Geneva. Detector Research and Development Committee

    1992-01-01

    The high radiation level expected in the inner regions of the high luminosity LHC detectors (gamma and neutron) will require radiation hardened electronics. A consortium between the CEA (Commissariat a l'Energie Atomique) and Thomson TMS (Thomson Composants Militaires et Spatiaux) has been created to push for the development and the industrialization of a nascent technology which looks particularly adapted to the needs of HEP electronics. This technology, currently under development at the LETI(CEA), uses a SIMOX substrate with an epitaxial silicon film. It includes CMOS, JFETs and vertical bipolar transistors with a potential multi-megarad hardness. The CMOS and bipolar transistors constitute a rad-hard BiCMOS which will be useful to design analog and digital high-speed architectures. JFETs, which have intrinsically high hardness behaviour and low noise performances even at low temperature will enable very rad-hard, low noise front end electronics to be designed. Present results, together with the improvemen...

  17. Space Station Habitability Recommendations Based on a Systematic Comparative Analysis of Analogous Conditions

    Science.gov (United States)

    Stuster, Jack W.

    1986-01-01

    Conditions analogous to the proposed NASA Space Station are systematically analyzed in order to extrapolate design guidelines and recommendations concerning habitability and crew productivity. Analogous environments studied included Skylab, Sealab, Tektite, submarines, Antarctic stations and oil drilling platforms, among others. These analogues were compared and rated for size and composition of group, social organization, preparedness for mission, duration of tour, types of tasks, physical and psychological isolation, personal motivation, perceived risk, and quality of habitat and life support conditions. One-hundred design recommendations concerning, sleep, clothing, exercise, medical support, personal hygiene, food preparation, group interaction, habitat aesthetics, outside communications, recreational opportunities, privacy and personal space, waste disposal, onboard training, simulation and task preparation, and behavioral and physiological requirements associated with a microgravity environment, are provided.

  18. Fair Electronic Payment Scheme Based on DSA

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-bin; HONG Fan; ZHU Xian

    2005-01-01

    We present a multi-signature scheme based on DSA and describes a fair electronic payment scheme based on improved DSA signatures. The scheme makes both sides in equal positions during the course of electronic transaction. A Trusted Third Party (TTP) is involved in the scheme to guarantee the fairness of the scheme for both sides. However, only during the course of registration and dispute resolution will TTP be needed. TTP is not needed during the normal payment stage.

  19. Connect high speed analog-digital converter with EPICS based on LabVIEW

    International Nuclear Information System (INIS)

    This paper introduce a method to connect high speed analog-digital converter (ADC212/100) with EPICS on Windows platform using LabVIEW. We use labVIEW to communicate with the converter, then use interface sub-VIs between LabVIEW and EPICS to access the EPICS IOC by Channel Access (CA). For the easy use graph programming language of LabVIEW, this method could shorten the develop period and reduce manpower cost. (authors)

  20. Post-Correction of Pipelined Analog-Digital Converters Based on Input Dependent Integral Nonlinearity Modeling

    OpenAIRE

    Samer Medawar; Peter H\\xe4ndel; Niclas Bj\\xf6rsell; Magnus Jansson

    2010-01-01

    The integral nonlinearity (INL) is used for the postcorrection of analog-digital converters (ADCs). An input-frequency-dependent INL model is developed for the postcorrection. The model consists of a static term that is dependent on the ADC output code and a dynamic term that has an additional dependence on the input frequency. The concept of ADC digital output postcorrection by INL is first introduced. The INL model is subtracted from the digital output for postcorrection. The static compens...

  1. Anonymous Fingerprinting Based on Electronic Cash

    Institute of Scientific and Technical Information of China (English)

    CHENXiaofeng; ZHANGFangguo; WANGJilin; WANGYumin

    2003-01-01

    A new anonymous fingerprinting protocol based on the principle of electronic cash is proposed in this paper.Redistributing a data item is equal to doublespending electronic cash.Contrasting with the previous coin-based anonymous fingerprinting protocol,we use the real electronic cash to trace traitors instead of the "coins" which serve only as a cryptographic primitive and have no monetary value,so it is easily understood and the bank does not need key-distribution and registration to prepare the "coina".

  2. Combined structure- and ligand-based virtual screening to evaluate caulerpin analogs with potential inhibitory activity against monoamine oxidase B

    Directory of Open Access Journals (Sweden)

    Vitor Prates Lorenzo

    2015-12-01

    Full Text Available Abstract Natural marine products can help increase the quality of life in patients with neurological diseases. A large number of marine products act against Alzheimer's disease through varying pathways. According to structure- and ligand-based analyses, caulerpin, an alkaloid primarily isolated from the genus Caulerpa, possesses activity against monoamine oxidase B. To predict the activity of caulerpin, we employed Volsurf descriptors and the machine learning Random Forest algorithm in parallel with a structure-based methodology that included molecular docking. Using caulerpin as a lead compound, a database containing 108 analogs was evaluated, and nine were selected as active. The structures selected as active exhibited polar and non-polar substitutions on the caulerpin skeleton, which were relevant for their activity. Dragon consensus drug-like scoring was applied to identify the active analogs that might serve as good drug candidates, and the entire group presented satisfactory performance. These results indicate the possibility of using these analogs as potential leads against Alzheimer's disease.

  3. Low-voltage analog front-end processor design for ISFET-based sensor and H+ sensing applications

    Science.gov (United States)

    Chung, Wen-Yaw; Yang, Chung-Huang; Peng, Kang-Chu; Yeh, M. H.

    2003-04-01

    This paper presents a modular-based low-voltage analog-front-end processor design in a 0.5mm double-poly double-metal CMOS technology for Ion Sensitive Field Effect Transistor (ISFET)-based sensor and H+ sensing applications. To meet the potentiometric response of the ISFET that is proportional to various H+ concentrations, the constant-voltage and constant current (CVCS) testing configuration has been used. Low-voltage design skills such as bulk-driven input pair, folded-cascode amplifier, bootstrap switch control circuits have been designed and integrated for 1.5V supply and nearly rail-to-rail analog to digital signal processing. Core modules consist of an 8-bit two-step analog-digital converter and bulk-driven pre-amplifiers have been developed in this research. The experimental results show that the proposed circuitry has an acceptable linearity to 0.1 pH-H+ sensing conversions with the buffer solution in the range of pH2 to pH12. The processor has a potential usage in battery-operated and portable healthcare devices and environmental monitoring applications.

  4. Hierarchical self-assembly of switchable nucleolipid supramolecular gels based on environmentally-sensitive fluorescent nucleoside analogs

    Science.gov (United States)

    Nuthanakanti, Ashok; Srivatsan, Seergazhi G.

    2016-02-01

    proven applications in nanotechnology, scalability and fabrication of nucleic acid nanostructures still remain a challenge. Here, we describe a novel design strategy to construct new supramolecular nucleolipid synthons by using environmentally-sensitive fluorescent nucleoside analogs, based on 5-(benzofuran-2-yl)uracil and 5-(benzo[b]thiophen-2-yl)uracil cores, as the head group and fatty acids, attached to the ribose sugar, as the lipophilic group. These modified nucleoside-lipid hybrids formed organogels driven by hierarchical structures such as fibers, twisted ribbons, helical ribbons and nanotubes, which depended on the nature of fatty acid chain and nucleobase modification. NMR, single crystal X-ray and powder X-ray diffraction studies revealed the coordinated interplay of various non-covalent interactions invoked by modified nucleobase, sugar and fatty acid chains in setting up the pathway for the gelation process. Importantly, these nucleolipid gels retained or displayed aggregation-induced enhanced emission and their gelation behavior and photophysical properties could be reversibly switched by external stimuli such as temperature, ultrasound and chemicals. Furthermore, the switchable nature of nucleolipid gels to chemical stimuli enabled the selective two channel recognition of fluoride and Hg2+ ions through visual phase transition and fluorescence change. Fluorescent organogels exhibiting such a combination of useful features is rare, and hence, we expect that this innovative design of fluorescent nucleolipid supramolecular synthons could lead to the emergence of a new family of smart optical materials and probes. Electronic supplementary information (ESI) available: Supplementary figures, tables, experimental procedures, crystallography data and NMR spectra. See DOI: 10.1039/c5nr07490h

  5. Electronic structure of Fe-based superconductors

    Indian Academy of Sciences (India)

    Kalobaran Maiti

    2015-06-01

    Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the dominant role of states in their electronic properties, which is significantly different from the cuprate superconductors. In this article, some of our studies of the electronic structure of these fascinating systems employing high-resolution photoemission spectroscopy is reviewed. The combined effect of electron correlation and covalency reveals an interesting scenario in their electronic structure. The contribution of ligand states at the Fermi level is found to be much more significant than indicated in earlier studies. Temperature evolution of the energy bands reveals the signature of transition akin to Lifshitz transition in these systems.

  6. Electronic structure of Fe-based superconductors

    International Nuclear Information System (INIS)

    Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the dominant role of d states in their electronic properties, which is significantly different from the cuprate superconductors. In this article, some of our studies of the electronic structure of these fascinating systems employing high-resolution photoemission spectroscopy is reviewed. The combined effect of electron correlation and covalency reveals an interesting scenario in their electronic structure. The contribution of ligand p states at the Fermi level is found to be much more significant than indicated in earlier studies. Temperature evolution of the energy bands reveals the signature of transition akin to Lifshitz transition in these systems. (author)

  7. Electronic Seal Stamping Based on Group Signature

    Directory of Open Access Journals (Sweden)

    Girija Srikanth

    2011-05-01

    Full Text Available This paper describes a new electronic official seal stamping based on Group Signature, USB Key. Bill/Contract in E-commerce must be seal stamped to gain tamper proof and non-repudiation. The seal stamping control is designed based on the certificate-based public key. This technique is more efficient for generating and verifying individual/group signatures in terms of computational efforts and communication costs. Web page electronic seal-stamping system is implemented which has been adopted by CNBAB platform since Mar., 2008

  8. TSET: Token based Secure Electronic Transaction

    OpenAIRE

    Borgohain, Rajdeep; Singh, Moirangthem Tiken; Sakharwade, Chandrakant; Sanyal, Sugata

    2012-01-01

    Security and trust are the most important factors in online transaction, this paper introduces TSET a Token based Secure Electronic Transaction which is an improvement over the existing SET, Secure Electronic Transaction protocol. We take the concept of tokens in the TSET protocol to provide end to end security. It also provides trust evaluation mechanism so that trustworthiness of the merchants can be known by customers before being involved in the transaction. Moreover, we also propose a gr...

  9. DNA-based applications in molecular electronics

    OpenAIRE

    Linko, Veikko

    2011-01-01

    This thesis is mainly focused on DNA molecules and especially on self-assembled DNA constructs and their potential applications in nanotechnology and molecular electronics. In the field of molecular electronics the conductivity of DNA is a crucial - yet open - question, and it is of great concern, since DNA is a very promising molecule in a context of bottom-up based nanodevices due to its superior selfassembly characteristics. A key tool in all the experiments presented in ...

  10. Fullerene based devices for molecular electronics

    OpenAIRE

    G. Cuniberti; R. GUTIERREZ; Fagas, G.; Grossmann, F.; Richter, K; Schmidt, R.

    2001-01-01

    We have investigated the electronic properties of a C_60 molecule in between carbon nanotube leads. This problem has been tackled within a quantum chemical treatment utilizing a density functional theory-based LCAO approach combined with the Landauer formalism. Owing to low-dimensionality, electron transport is very sensitive to the strength and geometry of interfacial bonds. Molecular contact between interfacial atoms and electrodes gives rise to a complex conductance dependence on the elect...

  11. A PER2-derived mechanism-based bisubstrate analog for casein kinase 1ε.

    Science.gov (United States)

    Zeringo, Nicholas A; Bellizzi, John J

    2014-12-01

    Casein kinase 1ε (CK1ε) plays an important regulatory role in various cellular processes including circadian rhythms. Mutations in CK1ε or the recognition site on its substrate PER2 result in modulation of the circadian period length. In particular, the tau mutation (R178C) in the catalytic domain of CK1ε was identified as the molecular basis for a dose-dependent heritable shortened circadian period in hamsters. However, the biochemical basis for the physiological effects of the tau mutant remains unclear. It has been reported that the tau mutation has reduced in vitro activity against some substrates but increased in vitro activity against other substrates. To better understand the effects of the CK1ε tau mutation, an ATP-phosphopeptide conjugate was synthesized to yield a transition-state bisubstrate analog. Kinase activity assays determined that the tau mutant has 80% reduced activity and a fourfold decrease in sensitivity to the bisubstrate analog compared to wild type. This confirms that Arg178 is important in the recognition of the preferred phosphosubstrates of CK1ε. PMID:24985607

  12. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  13. Novel acridine-based N-acyl-homoserine lactone analogs induce endoreduplication in the human oral squamous carcinoma cell line SAS

    International Nuclear Information System (INIS)

    The cytotoxicity of novel acridine-based N-acyl-homoserine lactone (AHL) analogs was investigated on the human oral squamous carcinoma cell line SAS. One analog induced G2/M phase arrest at 5.3-10.6 μM and induced polyploidy at a higher dose (21.2 μM). Importantly, treatment of SAS cells with a combination of the AHL analog and the Jun N-terminal kinase (JNK) inhibitor, SP600125, prevented mitosis and induced polyploidy. The AHL analog synergized with X-irradiation to inhibit clonogenic survival of SAS cells; however, its radiosensitizing effects were relative to not X-irradiation-induced apoptosis but mitotic failure following enhanced expression of Aurora A and B. These results suggest that the active AHL analog showed growth-suppressive and radiosensitizing effects, which involve polyploidy followed by G2/M accumulation and atypical cell death in the SAS cell line. (author)

  14. Associative Pattern Recognition In Analog VLSI Circuits

    Science.gov (United States)

    Tawel, Raoul

    1995-01-01

    Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

  15. MOF-based electronic and opto-electronic devices.

    Science.gov (United States)

    Stavila, V; Talin, A A; Allendorf, M D

    2014-08-21

    Metal-organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure-property relationships to identify and rationalize the factors that impact device performance. PMID:24802763

  16. Alternate source term models for Yucca Mountain performance assessment based on natural analog data and secondary mineral solubility

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, W.M.; Codell, R.B.

    1999-07-01

    Performance assessment calculations for the proposed high level radioactive waste repository at Yucca Mountain, Nevada, were conducted using the Nuclear Regulatory Commission Total-System Performance Assessment (TPA 3.2) code to test conceptual models and parameter values for the source term based on data from the Pena Blanca, Mexico, natural analog site and based on a model for coprecipitation and solubility of secondary schoepite. In previous studies the value for the maximum constant oxidative alteration rate of uraninite at the Nopal I uranium body at Pena Blanca was estimated. Scaling this rate to the mass of uranium for the proposed Yucca Mountain repository yields an oxidative alteration rate of 22 kg/y, which was assumed to be an upper limit on the release rate from the proposed repository. A second model was developed assuming releases of radionuclides are based on the solubility of secondary schoepite as a function of temperature and solution chemistry. Releases of uranium are given by the product of uranium concentrations at equilibrium with schoepite and the flow of water through the waste packages. For both models, radionuclides other than uranium and those in the cladding and gap fraction were modeled to be released at a rate proportional to the uranium release rate, with additional elemental solubility limits applied. Performance assessment results using the Pena Blanca oxidation rate and schoepite solubility models for Yucca Mountain were compared to the TPA 3.2 base case model, in which release was based on laboratory studies of spent fuel dissolution, cladding and gap release, and solubility limits. Doses calculated using the release rate based on natural analog data and the schoepite solubility models were smaller than doses generated using the base case model. These results provide a degree of confidence in safety predictions using the base case model and an indication of how conservatism in the base case model may be reduced in future analyses.

  17. Alternate source term models for Yucca Mountain performance assessment based on natural analog data and secondary mineral solubility

    International Nuclear Information System (INIS)

    Performance assessment calculations for the proposed high level radioactive waste repository at Yucca Mountain, Nevada, were conducted using the Nuclear Regulatory Commission Total-System Performance Assessment (TPA 3.2) code to test conceptual models and parameter values for the source term based on data from the Pena Blanca, Mexico, natural analog site and based on a model for coprecipitation and solubility of secondary schoepite. In previous studies the value for the maximum constant oxidative alteration rate of uraninite at the Nopal I uranium body at Pena Blanca was estimated. Scaling this rate to the mass of uranium for the proposed Yucca Mountain repository yields an oxidative alteration rate of 22 kg/y, which was assumed to be an upper limit on the release rate from the proposed repository. A second model was developed assuming releases of radionuclides are based on the solubility of secondary schoepite as a function of temperature and solution chemistry. Releases of uranium are given by the product of uranium concentrations at equilibrium with schoepite and the flow of water through the waste packages. For both models, radionuclides other than uranium and those in the cladding and gap fraction were modeled to be released at a rate proportional to the uranium release rate, with additional elemental solubility limits applied. Performance assessment results using the Pena Blanca oxidation rate and schoepite solubility models for Yucca Mountain were compared to the TPA 3.2 base case model, in which release was based on laboratory studies of spent fuel dissolution, cladding and gap release, and solubility limits. Doses calculated using the release rate based on natural analog data and the schoepite solubility models were smaller than doses generated using the base case model. These results provide a degree of confidence in safety predictions using the base case model and an indication of how conservatism in the base case model may be reduced in future analyses

  18. An alpha–gamma coincidence spectrometer based on the photon–electron rejecting alpha liquid scintillation (PERALS®) system

    International Nuclear Information System (INIS)

    An alpha–gamma coincidence spectrometer has been developed for the measurement of selected actinide isotopes in the presence of high beta/gamma fields. The system is based on a PERALS® liquid scintillation counter for beta/alpha discrimination and was successfully tested with both high purity germanium and bismuth germanate, gamma-ray detectors using conventional analog electronics

  19. Challenges in Analogical Reasoning

    CERN Document Server

    Lin, Shih-Yin

    2016-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  20. Peripheral substitution as a tool for tuning electron-accepting properties of phthalocyanine analogs in intramolecular charge transfer.

    Science.gov (United States)

    Cidlina, Antonin; Novakova, Veronika; Miletin, Miroslav; Zimcik, Petr

    2015-04-21

    The intramolecular charge transfer (ICT), which is a pathway for excited state relaxation, was studied on the newly synthesized zinc(ii) complexes of tetrapyrazinoporphyrazines bearing one fixed donor (i.e., a dialkylamino substituent). The rest of the peripheral substituents on the core was designed with respect to their different electronic effects (OBu, neopentyl, StBu, COOBu). The photophysical (singlet oxygen and fluorescence quantum yields) and electrochemical (reduction potentials) properties were determined and compared within the series and with compounds that did not contain a donor moiety. The ICT efficiency correlated well with both the electron-deficient character of the core and the Hammett substituent constants σp. The most efficient ICT was observed for the core with the most electron-accepting substituent (COOBu), and the lowest ICT efficiency was detected for the least electron-deficient core (substituted by OBu). Titration of DMSO solutions of target compounds with H2SO4 indicated that basicity of the azomethine bridges was largely influenced by the character of the peripheral substituents while the dialkylamino donor center remained nearly unaffected. Furthermore, protonation of the donor nitrogen caused partial restoration of the fluorescence quantum yield (increase up to 90 times) due to blocking of ICT. The results implied that the ICT efficiency was strongly dependent on the electron-accepting properties of the core whose properties can be readily affected by suitable selection of peripheral substituents. PMID:25782137

  1. Metamaterial perfect absorber based hot electron photodetection.

    Science.gov (United States)

    Li, Wei; Valentine, Jason

    2014-06-11

    While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991

  2. Design of A 5-Bit Fully Parallel Analog to Digital Converter Using Common Gate Differrential Mos Pair-Based Comparator

    Science.gov (United States)

    Aytar, Oktay

    2015-09-01

    This paper presents a novel comparator structure based on the common gate differential MOS pair. The proposed comparator has been applied to fully parallel analog to digital converter (A/D converter). Furthermore, this article presents 5 bit fully parallel A/D Converter design using the cadence IC5141 design platform and NCSU(North Carolina State University) design kit with 0.18 μm CMOS technology library. The proposed fully parallel A/D converter consist of resistor array block, comparator block, 1-n decoder block and programmable logic array. The 1-n decoder block includes latch block and thermometer code circuit that is implemented using transmission gate based multiplexer circuit. Thus, sampling frequency and analog bandwidth are increased. The INL and DNL of the proposed fully parallel A/D converter are (0/ + 0.63) LSB and (-0.26/ + 0.31) LSB at a sampling frequency of 5 GS/s with an input signal of 50 MHz, respectively. The proposed fully parallel A/D Converter consumes 340 mW from 1.8 V supply.

  3. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  4. Analog Genetic Encoding for the Evolution of Circuits and Networks

    OpenAIRE

    Mattiussi, Claudio; Floreano, Dario

    2007-01-01

    This paper describes a new kind of genetic representation called analog genetic encoding (AGE). The representation is aimed at the evolutionary synthesis and reverse engineering of circuits and networks such as analog electronic circuits, neural networks, and genetic regulatory networks. AGE permits the simultaneous evolution of the topology and sizing of the networks. The establishment of the links between the devices that form the network is based on an implicit definition of the interactio...

  5. Molybdenum cofactor-dependent resistance to N-hydroxylated base analogs in Escherichia coli is independent of MobA function

    International Nuclear Information System (INIS)

    Lack of molybdenum cofactor (MoCo) in Escherichia coli and related microorganisms was found to cause hypersensitivity to certain N-hydroxylated base analogs, such as HAP (6-N-hydroxylaminopurine). This observation has lead to a previous proposal that E. coli contains a molybdoenzyme capable of detoxifying such N-hydroxylated analogs. Here, we show that, unexpectedly, deletion of all known or putative molybdoenzymes in E. coli failed to reveal any base-analog sensitivity, suggesting that a novel type of MoCo-dependent activity is involved. Further, we establish that protection against the analogs does not require the common molybdopterin guanine-dinucleotide (MGD) form of the cofactor, but instead the guanosine monophosphate (GMP)-free version of MoCo (MPT) is sufficient

  6. TSET: Token based Secure Electronic Transaction

    CERN Document Server

    Borgohain, Rajdeep; Sakharwade, Chandrakant; Sanyal, Sugata

    2012-01-01

    Security and trust are the most important factors in online transaction, this paper introduces TSET a Token based Secure Electronic Transaction which is an improvement over the existing SET, Secure Electronic Transaction protocol. We take the concept of tokens in the TSET protocol to provide end to end security. It also provides trust evaluation mechanism so that trustworthiness of the merchants can be known by customers before being involved in the transaction. Moreover, we also propose a grading mechanism so that quality of service in the transactions improves.

  7. Data base systems in electronic design engineering

    Science.gov (United States)

    Williams, D.

    1980-01-01

    The concepts of an integrated design data base system (DBMS) as it might apply to an electronic design company are discussed. Data elements of documentation, project specifications, project tracking, firmware, software, electronic and mechanical design can be integrated and managed through a single DBMS. Combining the attributes of a DBMS data handler with specialized systems and functional data can provide users with maximum flexibility, reduced redundancy, and increased overall systems performance. Although some system overhead is lost due to redundancy in transitory data, it is believed the combination of the two data types is advisable rather than trying to do all data handling through a single DBMS.

  8. A Sub Threshold Source Coupled Logic Based Design of Low Power CMOS Analog Multiplexer

    Directory of Open Access Journals (Sweden)

    G.Deepika

    2014-08-01

    Full Text Available A novel approach for designing Ultra Low Power and wide dynamic range circuit for multiplexing analog signals is presented. The design operates in weak i nversion (Sub threshold region and uses Source - Coupled Logic ( SCL circuit. The bias current of t he SCL gates is varied to scale down linearly the p ower consumption and the operating frequency. The multip lexer design employs CMOS transistors as transmission gate with dynamic threshold voltage. T he design exhibits low power dissipation, high dynamic range and good linearity. The design was im plemented in 180 nm technology and was operated at a supply voltage of 400 mV with a bias current rang ing in the order of few Pico-amperes. The ON and OFF resistance of the transmission gate achieved we re 27 ohms and 10 M ohms respectively. The power dissipation achieved is around 0.79 μ W for a dynami c range of 1μ V to 0.4 V.

  9. Communication: Electron ionization of DNA bases.

    Science.gov (United States)

    Rahman, M A; Krishnakumar, E

    2016-04-28

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space. PMID:27131520

  10. Performance investigation of InAs based dual electrode tunnel FET on the analog/RF platform

    Science.gov (United States)

    Anand, Sunny; Sarin, R. K.

    2016-09-01

    In this paper for the first time, InAs based doping-less Tunnel FET is proposed and investigated. This paper also demonstrates and discusses the impact of gate stacking (SiO2 + HfO2) with equivalent oxide thickness EOT = 0.8 for analog/RF performance. The charge plasma technique is used to form source/drain region on an intrinsic InAs body by selecting proper work function of metal electrode. The paper compares different combinations of gate stacking (SiO2 and HfO2) on the basis of different analog and RF parameters such as transconductance (gm), transconductance to drive current ratio (gm/ID), output conductance (gd), intrinsic gain (AV), total gate capacitance (Cgg) and unity-gain cutoff frequency (fT). The proposed device produces an ON state current of ION ∼6 mA along with ION/IOFF ∼1012, point subthreshold slope (SS ∼ 1.9 mV/dec), average subthreshold slope (AV-SS ∼ 14.2 mV/dec) and cut-off frequency in Terahertz. The focus of this work is to eliminate the fabrication issues and providing the enhanced performance compared to doped device.

  11. Fault Modeling and Testing for Analog Circuits in Complex Space Based on Supply Current and Output Voltage

    Directory of Open Access Journals (Sweden)

    Hongzhi Hu

    2015-01-01

    Full Text Available This paper deals with the modeling of fault for analog circuits. A two-dimensional (2D fault model is first proposed based on collaborative analysis of supply current and output voltage. This model is a family of circle loci on the complex plane, and it simplifies greatly the algorithms for test point selection and potential fault simulations, which are primary difficulties in fault diagnosis of analog circuits. Furthermore, in order to reduce the difficulty of fault location, an improved fault model in three-dimensional (3D complex space is proposed, which achieves a far better fault detection ratio (FDR against measurement error and parametric tolerance. To address the problem of fault masking in both 2D and 3D fault models, this paper proposes an effective design for testability (DFT method. By adding redundant bypassing-components in the circuit under test (CUT, this method achieves excellent fault isolation ratio (FIR in ambiguity group isolation. The efficacy of the proposed model and testing method is validated through experimental results provided in this paper.

  12. Determining the electronic triplet-singlet transition probability in double quantum dots: Analogy with the double slit experiment

    OpenAIRE

    Domínguez, Fernando; Platero, Gloria

    2009-01-01

    We apply an elementary measurement scheme to calculate the electronic triplet-singlet transition mediated by hyperfine interaction in a double quantum dot. We show how the local character of the hyperfine interaction and the nuclear back-action process (flip-flop) are crucial to cancel destructive interferences of the triplet-singlet transition probability. It is precisely this cancellation which differentiates the hyperfine interaction from an anisotropic magnetic field which mixes the tripl...

  13. The Effects of Spaceflight and a Spaceflight Analog on Neurocognitive Perfonnance: Extent, Longevity, and Neural Bases

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Erdeniz, B.; Kofman, I. S.; DeDios, Y. E.; Szecsy, D. L.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

    2014-01-01

    We are conducting ongoing experiments in which we are performing structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations following a six month International Space Station mission and following 70 days exposure to a spaceflight analog, head down tilt bedrest. Our central hypothesis is that measures of brain structure, function, and network integrity will change from pre to post intervention (spaceflight, bedrest). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a neuroanatomically selective fashion. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad ranging battery of sensory, motor, and cognitive assessments that will be conducted pre flight, during flight, and post flight to investigate potential neuroplastic and maladaptive brain changes in crewmembers following long-duration spaceflight. Success in this endeavor would 1) result in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior, and 2) identify whether a return to normative behavioral function following re-adaptation to Earth's gravitational environment is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes. With the bedrest study, we will be able to determine the neural and neurocognitive effects of extended duration unloading, reduced sensory inputs, and increased cephalic fluid distribution. This will enable us to parse out the multiple mechanisms contributing to any spaceflight-induced neural structural and behavioral changes that we observe in the flight study. In this presentation I will discuss preliminary results from six participants who have undergone the bed rest protocol. These individuals show decrements in balance and functional mobility

  14. Graphene-based Electronically Tuneable Microstrip Attenuator

    Directory of Open Access Journals (Sweden)

    L. Pierantoni

    2014-06-01

    Full Text Available This paper presents the design of a graphene- based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator.

  15. Electrical analogous in viscoelasticity

    Science.gov (United States)

    Ala, Guido; Di Paola, Mario; Francomano, Elisa; Li, Yan; Pinnola, Francesco P.

    2014-07-01

    In this paper, electrical analogous models of fractional hereditary materials are introduced. Based on recent works by the authors, mechanical models of materials viscoelasticity behavior are firstly approached by using fractional mathematical operators. Viscoelastic models have elastic and viscous components which are obtained by combining springs and dashpots. Various arrangements of these elements can be used, and all of these viscoelastic models can be equivalently modeled as electrical circuits, where the spring and dashpot are analogous to the capacitance and resistance, respectively. The proposed models are validated by using modal analysis. Moreover, a comparison with numerical experiments based on finite difference time domain method shows that, for long time simulations, the correct time behavior can be obtained only with modal analysis. The use of electrical analogous in viscoelasticity can better reveal the real behavior of fractional hereditary materials.

  16. Rover-Based Instrumentation and Scientific Investigations During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii

    Science.gov (United States)

    Graham, L. D.; Graff, T. G.

    2013-01-01

    Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) were recently completed on Mauna Kea Volcano, Hawaii. Scientific investigations, scientific input, and operational constraints were tested in the context of existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration [1]. Several investigations were conducted by the rover mounted instruments to determine key geophysical and geochemical properties of the site, as well as capture the geological context of the area and the samples investigated. The rover traverse and associated science investigations were conducted over a three day period on the southeast flank of the Mauna Kea Volcano, Hawaii. The test area was at an elevation of 11,500 feet and is known as "Apollo Valley" (Fig. 1). Here we report the integration and operation of the rover-mounted instruments, as well as the scientific investigations that were conducted.

  17. Developments of gamma-ray imagers using CdTe semiconductors based on the analog ASIC technology

    International Nuclear Information System (INIS)

    Cadmium Telluride (CdTe) is one of the most promising semiconductor materials for hard X-ray and gamma-ray detection because of the high detection efficiency, and of the good energy resolution. Moreover, CdTe detectors with Schottky junction work as diode detectors, and show superior energy resolution. Based on the CdTe diode devices, we have developed CdTe pixel/strip imagers, and also realized a Si/CdTe Compton camera. These devices will be used for the Hard X-ray Imager (HXI) and the Soft Gamma-ray Detector (SGD) onboard ASTRO-H X-ray satellite to be launched in 2015. These developments are briefly reported in this article. We also describe our recent development of low-noise analog readout ASICs to be used for future development of CdTe gamma-ray imagers. (author)

  18. Explanation-based knowledge acquisition of electronics

    Science.gov (United States)

    Kieras, David E.

    1992-08-01

    This is the final report in a project that examined how knowledge of practical electronics could be acquired from materials similar to that appearing in electronics training textbooks, from both an artificial intelligence perspective and an experimental psychology perspective. Practical electronics training materials present a series of basic circuits accompanied by an explanation of how the circuit performs the desired function. More complex circuits are then explained in terms of these basic circuits. This material thus presents schema knowledge for individual circuit types in the form of explanations of circuit behavior. Learning from such material would thus consist of first instantiating any applicable schemas, and then constructing a new schema based on the circuit structure and behavior described in the explanation. If the basic structure of the material is an effective approach to learning, learning about a new circuit should be easier if the relevant schemas are available than not. This result was obtained for both an artificial intelligence system that used standard explanation-based learning mechanisms and with human learners in a laboratory setting, but the benefits of already having the relevant schemas were not large in these materials. The close examination of learning in this domain, and the structure of knowledge, should be useful to future cognitive analyses of training in technical domains.

  19. The Design of an Analogical Encoding Tool for Game-Based Virtual Learning Environments

    Science.gov (United States)

    Williams, Douglas; Ma, Yuxin; Feist, Steven; Richard, Charles E.; Prejean, Louise

    2007-01-01

    Game-based virtual learning environments have the potential to provide opportunities for engagement in authentic contexts while completing authentic tasks such as problem solving. However, research in problem-based learning indicates that scaffolding should be provided for learners to benefit from such learning environments. This paper describes…

  20. The temperature effect on the glycine decomposition induced by 2 keV electron bombardment in space analog conditions

    Science.gov (United States)

    Pilling, Sergio; Nair, Binu G.; Escobar, Antonio; Fraser, Helen; Mason, Nigel

    2014-03-01

    Glycine is the simplest proteinaceous amino acid that has been extensively detected in carbonaceous meteorites and was recently observed in the cometary samples returned to Earth by NASA's Stardust spacecraft. In space, such species is exposed to several radiation fields at different temperatures. In aqueous solutions, this species appears mainly as zwitterionic glycine (+NH3CH2COO-) however, in solid phase, it may be found in amorphous or crystalline forms. Here, we present an experimental study on the destruction of two zwitterionic glycine crystals ( α- and β-form) at two different temperatures (300 K and 14 K) by 2 keV electrons in an attempt to test the behavior and stability of this molecular species in different space environments. The samples were analyzed in situ by Fourier transform infrared spectrometry at electron fluences. The experiments were carried out under ultra-high vacuum conditions at the Molecular Physics Laboratory at the Open University at Milton Keynes, UK. The dissociation cross section of glycine is approximately 5 times higher for the 14 K samples when compared to the 300 K samples. In contrast, no significant differences emerged between the dissociation cross sections of α- and β-forms of glycine for fixed temperature experiments. We therefore conclude that the destruction cross section is more heavily dependent on temperature than the phase of the condensed glycine material. This may be associated with the opening of additional reaction routes in the frozen samples involving the trapped daughter species (e.g. CO2 and CO). The half-life of studied samples extrapolated to space conditions shows that glycine molecules on the surface of interstellar grains has less survivability and they are highly sensitive to ambient radiations, however, they can survive extended period of time in the solar system like environments. Survivability increases by a factor of 5 if the samples are at 300 K when compared to low temperature experiments at 14

  1. DIRECT DETECTION OF COMPLEX ORGANIC PRODUCTS IN ULTRAVIOLET (Lyα) AND ELECTRON-IRRADIATED ASTROPHYSICAL AND COMETARY ICE ANALOGS USING TWO-STEP LASER ABLATION AND IONIZATION MASS SPECTROMETRY

    International Nuclear Information System (INIS)

    As discovery of complex molecules and ions in our solar system and the interstellar medium has proliferated, several groups have turned to laboratory experiments in an effort to simulate and understand these chemical processes. So far only infrared (IR) and ultraviolet (UV) spectroscopy has been able to directly probe these reactions in ices in their native, low-temperature states. Here we report for the first time results using a complementary technique that harnesses two-step two-color laser ablation and ionization to measure mass spectra of energetically processed astrophysical and cometary ice analogs directly without warming the ices—a method for hands-off in situ ice analysis. Electron bombardment and UV irradiation of H2O, CH3OH, and NH3 ices at 5 K and 70 K led to complex irradiation products, including HCO, CH3CO, formamide, acetamide, methyl formate, and HCN. Many of these species, whose assignment was also strengthened by isotope labeling studies and correlate with IR-based spectroscopic studies of similar irradiated ices, are important ingredients for the building blocks of life. Some of them have been detected previously via astronomical observations in the interstellar medium and in cometary comae. Other species such as CH3CO (acetyl) are yet to be detected in astrophysical ices or interstellar medium. Our studies suggest that electron and UV photon processing of astrophysical ice analogs leads to extensive chemistry even in the coldest reaches of space, and lend support to the theory of comet-impact-induced delivery of complex organics to the inner solar system

  2. Quantum Analog Computing

    Science.gov (United States)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  3. Electron-avalanche amplifier based on the electronic Venturi effect

    Science.gov (United States)

    Taubert, D.; Schinner, G. J.; Tranitz, H. P.; Wegscheider, W.; Tomaras, C.; Kehrein, S.; Ludwig, S.

    2010-10-01

    Scattering of otherwise ballistic electrons far from equilibrium is investigated in a cold two-dimensional electron system. The interaction between excited electrons and the degenerate Fermi liquid induces a positive charge in a nanoscale region which would be negatively charged for diffusive transport at local thermal equilibrium. In a three-terminal device we observe avalanche amplification of electrical current, resulting in a situation comparable to the Venturi effect in hydrodynamics. Numerical calculations using a random-phase approximation are in agreement with our data and suggest Coulomb interaction as the dominant scattering mechanism.

  4. Parametric estimation in the wave buoy analogy - an elaborated approach based on energy considerations

    DEFF Research Database (Denmark)

    Montazeri, Najmeh; Nielsen, Ulrik Dam

    2014-01-01

    ship’s wave-induced responses based on different statistical inferences including parametric and non-parametric approaches. This paper considers a concept to improve the estimate obtained by the parametric method for sea state estimation. The idea is illustrated by an analysis made on full-scale...

  5. Simulation analysis of analog IQ based LLRF control of RF cavity

    International Nuclear Information System (INIS)

    This paper presents the simulation work and results in Matlab Simulink for the analogue Inphase-Quadrature (IQ) based Low Level Radio Frequency (LLRF) control of RF cavity voltage. The RF cavity chosen here is the Radio Frequency Quadrupole (RFQ) cavity in our RIB project. All the subsystems in the IQ based RF control were modelled using the Simulink blocks/components. The envelope simulation was carried out using the IQ model of RF cavity. The PI controller was properly tuned to achieve good control performance in time. The simulation graphs showing the time evolution of the RF cavity voltage with a step change of the input reference signal is presented. The simulation graphs showing the control response time needed to correct a disturbance is presented. The simulation results showing Nichols plots of the control loop and the gain and phase margin values obtained from them are presented, which are good enough for stability considerations. (author)

  6. Anti-Cocaine Vaccine Based on Coupling a Cocaine Analog to a Disrupted Adenovirus

    OpenAIRE

    Koob, George; Hicks, Martin J.; Wee, Sunmee; Rosenberg, Jonathan B; De, Bishnu P.; Kaminksy, Stephen M.; Moreno, Amira; Kim D. Janda; Crystal, Ronald G.

    2011-01-01

    The challenge in developing an anti-cocaine vaccine is that cocaine is a small molecule, invisible to the immune system. Leveraging the knowledge that adenovirus (Ad) capsid proteins are highly immunogenic in humans, we hypothesized that linking a cocaine hapten to Ad capsid proteins would elicit high-affinity, high-titer antibodies against cocaine, sufficient to sequester systemically administered cocaine and prevent access to the brain, thus suppressing cocaine-induced behaviors. Based on t...

  7. Time-to-digital converter based on analog time expansion for 3D time-of-flight cameras

    Science.gov (United States)

    Tanveer, Muhammad; Nissinen, Ilkka; Nissinen, Jan; Kostamovaara, Juha; Borg, Johan; Johansson, Jonny

    2014-03-01

    This paper presents an architecture and achievable performance for a time-to-digital converter, for 3D time-of-flight cameras. This design is partitioned in two levels. In the first level, an analog time expansion, where the time interval to be measured is stretched by a factor k, is achieved by charging a capacitor with current I, followed by discharging the capacitor with a current I/k. In the second level, the final time to digital conversion is performed by a global gated ring oscillator based time-to-digital converter. The performance can be increased by exploiting its properties of intrinsic scrambling of quantization noise and mismatch error, and first order noise shaping. The stretched time interval is measured by counting full clock cycles and storing the states of nine phases of the gated ring oscillator. The frequency of the gated ring oscillator is approximately 131 MHz, and an appropriate stretch factor k, can give a resolution of ≍ 57 ps. The combined low nonlinearity of the time stretcher and the gated ring oscillator-based time-to-digital converter can achieve a distance resolution of a few centimeters with low power consumption and small area occupation. The carefully optimized circuit configuration achieved by using an edge aligner, the time amplification property and the gated ring oscillator-based time-to-digital converter may lead to a compact, low power single photon configuration for 3D time-of-flight cameras, aimed for a measurement range of 10 meters.

  8. A comparison of acceptance- and control-based strategies for coping with food cravings: an analog study.

    Science.gov (United States)

    Forman, Evan M; Hoffman, Kimberly L; McGrath, Kathleen B; Herbert, James D; Brandsma, Lynn L; Lowe, Michael R

    2007-10-01

    The present study utilized an analog paradigm to investigate the effectiveness of two strategies for coping with food cravings, which was theorized to be critical to the maintenance of weight loss. Ninety-eight undergraduate students were given transparent boxes of chocolate Hershey's Kisses and instructed to keep the chocolates with them, but not to eat them, for 48 h. Before receiving the Kisses, participants were randomized to receive either (a) no intervention, (b) instruction in control-based coping strategies such as distraction and cognitive restructuring, or (c) instruction in acceptance-based strategies such as experiential acceptance and defusion techniques. Measures included the Power of Food Scale (PFS; a measure of psychological sensitivity to the food environment), self-report ratings of chocolate cravings and surreptitiously recorded chocolate consumption. Results suggested that the effect of the intervention depended on baseline PFS levels, such that acceptance-based strategies were associated with better outcomes (cravings, consumption) among those reporting the highest susceptibility to the presence of food, but greater cravings among those who scored lowest on the PFS. It was observed that craving self-report measures predicted chocolate consumption, and baseline PFS levels predicted both cravings and consumption. Results are discussed in terms of the implications for weight loss maintenance strategies. PMID:17544361

  9. Multiparametric electronic devices based on nuclear tracks

    Energy Technology Data Exchange (ETDEWEB)

    Fink, D. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany)], E-mail: FINK@HMI.DE; Saad, A. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Basic Science Department, Faculty of Science, Al Balqa University, Salt (Jordan); Dhamodaran, S. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); School of Physics, University of Hyderabad, Hyderabad 500 046 (India); Chandra, A. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Fahrner, W.R. [Chair of Electronic Devices, Institute of Electrotechnique, Fernuniversitaet, Hagen (Germany); Hoppe, K. [South Westfalia University of Applied Sciences, Hagen (Germany); Chadderton, L.T. [Institute of Advanced Studies, ANU Canberra, GPO Box 4, ACT (Australia)

    2008-08-15

    An overview is given on a family of novel electronic devices consisting of an insulating layer containing conducting or semiconducting nuclear tracks, deposited on a semiconducting substrate, and connected by at least one back and two surface contacts. Conducting and semiconducting latent tracks may emerge directly from swift heavy ion irradiation. Etched tracks in insulators can be filled with adequate materials to make them conducting or semiconducting. For this purpose metallic or semiconducting nanoclusters were deposited. We have denoted termed these devices made with latent tracks as 'tunable electronic anisotropic material on semiconductor' (TEAMS), if based on latent ion tracks, and as 'tunable electronic material in pores in oxide on semiconductor' (TEMPOS), if based on etched tracks. Depending on the band-to-band transition between tracks and substrate and on the ratio of surface to track conductivity, the current/voltage characteristics of TEAMS and TEMPOS structures can be modified in many different ways leading to tunable resistors, capacitors and diodes. Both devices show negative differential resistances. This should enable tunable tunneldiodes. TEAMS or TEMPOS structures can be controlled by various external physical and/or chemical parameters leading to sensors. It is even possible to combine different input currents and/or external parameters according to AND/OR logics. The currents through a clustered layer on a TEMPOS structure can be described by the Barbasi-Albert model of network theory enabling to calculate a 'radius of influence'r{sub ROI} around each surface contact, beyond which neighboring contacts do not influence each other. The radius of influence can be well below 1{mu}m leading to nanometric TEMPOS structures.

  10. Spin orbit torque based electronic neuron

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Abhronil, E-mail: asengup@purdue.edu; Choday, Sri Harsha; Kim, Yusung; Roy, Kaushik [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2015-04-06

    A device based on current-induced spin-orbit torque (SOT) that functions as an electronic neuron is proposed in this work. The SOT device implements an artificial neuron's thresholding (transfer) function. In the first step of a two-step switching scheme, a charge current places the magnetization of a nano-magnet along the hard-axis, i.e., an unstable point for the magnet. In the second step, the SOT device (neuron) receives a current (from the synapses) which moves the magnetization from the unstable point to one of the two stable states. The polarity of the synaptic current encodes the excitatory and inhibitory nature of the neuron input and determines the final orientation of the magnetization. A resistive crossbar array, functioning as synapses, generates a bipolar current that is a weighted sum of the inputs. The simulation of a two layer feed-forward artificial neural network based on the SOT electronic neuron shows that it consumes ∼3× lower power than a 45 nm digital CMOS implementation, while reaching ∼80% accuracy in the classification of 100 images of handwritten digits from the MNIST dataset.

  11. Lunar and Hawaiian lava tubes: Analogs and uses based on terrestrial field data

    Science.gov (United States)

    Coombs, Cassandra R.; Hawke, B. Ray

    1991-01-01

    Presented here is an analysis of the data collected for a large number of Hawaiian lava tubes on the islands of Oahu, Molokai, and Hawaii. The results are extrapolated to lunar conditions. It is argued that lava tubes that formed on the Earth and the Moon are relatively stable over time, as illustrated by the ridigity of the Hawaiian prehistoric lava tubes as well as the historic tubes located in the bombing range near Mauna Loa. These natural structures should be considered for use in planning for the expansion and advanced stages of the future manned lunar base.

  12. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate (PMEA Analogous Polymers for Attachment-Based Cell Enrichment.

    Directory of Open Access Journals (Sweden)

    Takashi Hoshiba

    Full Text Available Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate (PMEA substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate (PBA and poly(tetrahydrofurfuryl acrylate (PTHFA, on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe2A and poly(2-(2-methoxyethoxy ethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe3A, which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment.

  13. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate) (PMEA) Analogous Polymers for Attachment-Based Cell Enrichment.

    Science.gov (United States)

    Hoshiba, Takashi; Nemoto, Eri; Sato, Kazuhiro; Orui, Toshihiko; Otaki, Takayuki; Yoshihiro, Ayano; Tanaka, Masaru

    2015-01-01

    Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment. PMID:26288362

  14. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  15. Towards power centric analog design

    OpenAIRE

    Svensson, Christer

    2015-01-01

    Power consumption of analog systems is poorly understoodtoday, in contrast to the very well developed analysis of digitalpower consumption. We show that there is good opportunity todevelop also the analog power understanding to a similar levelas the digital. Such an understanding will have a large impact inthe design of future electronic systems, where low power consumptionwill be crucial. Eventually we may reach a power centricanalog design methodology.

  16. Analog model

    International Nuclear Information System (INIS)

    The invention relates to devices for modelling the space-dependent kinetics of a nuclear reactor. It can be advantageously used in studying the dynamics of the neutron field in the core to determine the effect of the control rods on the power distribution in the core, for training purposes. The proposed analog model of a nuclear reactor comprises operational amplifiers and a grid of resistors simulating neutron diffusion. Connected to the grid nodes are supply resistors modelling absorption and multiplication of neutrons. This is achieved by that, in the proposed model, all resistors through which power is supplied to the grid nodes are interconnected by their other leads and coupled to the output of the amplifier unit common for all nodes. Therewith, the amlifier unit models the transfer function of a ''point'' reactor. Connected to the input of this unit which includes two to four amplifiers are resistors for addition of signals with a grid node. Coupled to the grid nodes via additional resistors are voltage sources simulating reactivity

  17. Application of polymer films based on bacteriorhodopsin and its analogs for low-light-level imaging systems

    Science.gov (United States)

    Korchemskaya, Elena Y.; Soskin, Marat S.; Stepanchikov, Dmitriy A.; Djukova, T. V.; Druzhko, Anna B.; Vsevolodov, Nicolai N.

    1995-03-01

    In recent years polymer films based on bacteriorhodopsin (BR) have attracted a lot of attention in the area of optical imaging systems. The high photosensitivity of these films allows the processing of low-power optical signals (several mW/cm2 CW gas laser irradiation). Spatial resolution does not fall below 5000 lines/mm, photoresponse time is 50 microsecond(s) and images can be recorded and erased over million cycles. Polymer film with BR combine a dynamic recording with optical image processing. The characteristics of anisotropically-saturating nonlinearity of polymer films with BR allow a suppression of the background with greater intensity than usable signal intensity of be performed. Low saturation intensity of the polymer films with BR allows the operation of the polarization of low-intensity signals to be realized. Nonlinear photoresponse of the high photosensitivity BR genetic variant Asp96-Glu is studied in this work too. We hope that the polymer films based on BR and its analogs will find potential use precisely in the medical low- light-level imaging systems.

  18. Successive approximation-like 4-bit full-optical analog-to-digital converter based on Kerr-like nonlinear photonic crystal ring resonators

    Science.gov (United States)

    Tavousi, Alireza; Mansouri-Birjandi, Mohammad Ali; Saffari, Mehdi

    2016-09-01

    Implementing of photonic sampling and quantizing analog-to-digital converters (ADCs) enable us to extract a single binary word from optical signals without need for extra electronic assisting parts. This would enormously increase the sampling and quantizing time as well as decreasing the consumed power. To this end, based on the concept of successive approximation method, a 4-bit full-optical ADC that operates using the intensity-dependent Kerr-like nonlinearity in a two dimensional photonic crystal (2DPhC) platform is proposed. The Silicon (Si) nanocrystal is chosen because of the suitable nonlinear material characteristic. An optical limiter is used for the clamping and quantization of each successive levels that represent the ADC bits. In the proposal, an energy efficient optical ADC circuit is implemented by controlling the system parameters such as ring-to-waveguide coupling coefficients, the ring's nonlinear refractive index, and the ring's length. The performance of the ADC structure is verified by the simulation using finite difference time domain (FDTD) method.

  19. Strip silicon waveguide for code synchronization in all-optical analog-to-digital conversion based on a lumped time-delay compensation scheme

    Science.gov (United States)

    Sha, Li; Zhi-Guo, Shi; Zhe, Kang; Chong-Xiu, Yu; Jian-Ping, Wang

    2016-04-01

    An all-optical analog-to-digital converter (ADC) based on the nonlinear effect in a silicon waveguide is a promising candidate for overcoming the limitation of electronic devices and is suitable for photonic integration. In this paper, a lumped time-delay compensation scheme with 2-bit quantization resolution is proposed. A strip silicon waveguide is designed and used to compensate for the entire time-delays of the optical pulses after a soliton self-frequency shift (SSFS) module within a wavelength range of 1550 nm–1580 nm. A dispersion coefficient as high as –19800 ps/(km·nm) with ±0.5 ps/(km·nm) variation is predicted for the strip waveguide. The simulation results show that the maximum supportable sampling rate (MSSR) is 50.45 GSa/s with full width at half maximum (FWHM) variation less than 2.52 ps, along with the 2-bit effective-number-of-bit and Gray code output. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. FRF-TP-15-030A1) and China Postdoctoral Science Foundation (Grant No. 2015M580978).

  20. Dual delivery systems based on polyamine analog BENSpm as prodrug and gene delivery vectors

    Science.gov (United States)

    Zhu, Yu

    Combination drug and gene therapy shows promise in cancer treatment. However, the success of such strategy requires careful selection of the therapeutic agents, as well as development of efficient delivery vectors. BENSpm (N 1, N11-bisethylnorspermine), a polyamine analogue targeting the intracellular polyamine pathway, draws our special attention because of the following reasons: (1) polyamine pathway is frequently dysregulated in cancer; (2) BENSpm exhibits multiple functions to interfere with the polyamine pathway, such as to up-regulate polyamine metabolism enzymes and down-regulate polyamine biosynthesis enzymes. Therefore BENSpm depletes all natural polyamines and leads to apoptosis and cell growth inhibition in a wide range of cancers; (3) preclinical studies proved that BENSpm can act synergistically with various chemotherapy agents, making it a promising candidate in combination therapy; (4) multiple positive charges in BENSpm enable it as a suitable building block for cationic polymers, which can be further applied to gene delivery. In this dissertation, our goal was to design dual-function delivery vector based on BENSpm that can function as a gene delivery vector and, after intracellular degradation, as an active anticancer agent targeting dysregulated polyamine metabolism. We first demonstrated strong synergism between BENSpm and a potential therapeutic gene product TRAIL. Strong synergism was obtained in both estrogen-dependent MCF-7 breast cancer cells and triple-negative MDA-MB-231 breast cancer cells. Significant dose reduction of TRAIL in combination with BENSpm in MDA-MB-231 cells, together with the fact that BENSpm rendered MCF-7 cells more sensitive to TRAIL treatment verified our rationale of designing BENSpm-based delivery platform. This was expected to be beneficial for overcoming drug resistance in chemotherapy, as well as boosting the therapeutic effect of therapeutic genes. We first designed a lipid-based BENSpm dual vector (Lipo

  1. Engineering a long-acting, potent GLP-1 analog for microstructure-based transdermal delivery

    Science.gov (United States)

    Yang, Peng-Yu; Zou, Huafei; Chao, Elizabeth; Sherwood, Lance; Nunez, Vanessa; Keeney, Michael; Ghartey-Tagoe, Esi; Ding, Zhongli; Quirino, Herlinda; Luo, Xiaozhou; Welzel, Gus; Chen, Guohua; Singh, Parminder; Woods, Ashley K.; Schultz, Peter G.; Shen, Weijun

    2016-01-01

    Antidiabetic treatments aiming to reduce body weight are currently gaining increased interest. Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist administered twice daily via s.c. injection, improves glycemic control, often with associated weight reduction. To further improve the therapeutic efficacy of exendin-4, we have developed a novel peptide engineering strategy that incorporates a serum protein binding motif onto a covalent side-chain staple and applied to the peptide to enhance its helicity and, as a consequence, its potency and serum half-life. We demonstrated that one of the resulting peptides, E6, has significantly improved half-life and glucose tolerance in an oral glucose tolerance test in rodents. Chronic treatment of E6 significantly decreased body weight and fasting blood glucose, improved lipid metabolism, and also reduced hepatic steatosis in diet-induced obese mice. Moreover, the high potency of E6 allowed us to administer this peptide using a dissolvable microstructure-based transdermal delivery system. Pharmacokinetic and pharmacodynamic studies in guinea pigs showed that a single 5-min application of a microstructure system containing E6 significantly improved glucose tolerance for 96 h. This delivery strategy may offer an effective and patient-friendly alternative to currently marketed GLP-1 injectables and can likely be extended to other peptide hormones. PMID:27035989

  2. Elevated Levels of DNA Strand Breaks Induced by a Base Analog in the Human Cell Line with the P32T ITPA Variant

    Directory of Open Access Journals (Sweden)

    Irina S.-R. Waisertreiger

    2010-01-01

    Full Text Available Base analogs are powerful antimetabolites and dangerous mutagens generated endogenously by oxidative stress, inflammation, and aberrant nucleotide biosynthesis. Human inosine triphosphate pyrophosphatase (ITPA hydrolyzes triphosphates of noncanonical purine bases (i.e., ITP, dITP, XTP, dXTP, or their mimic: 6-hydroxyaminopurine (HAP deoxynucleoside triphosphate and thus regulates nucleotide pools and protects cells from DNA damage. We demonstrate that the model purine base analog HAP induces DNA breaks in human cells and leads to elevation of levels of ITPA. A human polymorphic allele of the ITPA, 94C->A encodes for the enzyme with a P32T amino-acid change and leads to accumulation of nonhydrolyzed ITP. The polymorphism has been associated with adverse reaction to purine base-analog drugs. The level of both spontaneous and HAP-induced DNA breaks is elevated in the cell line with the ITPA P32T variant. The results suggested that human ITPA plays a pivotal role in the protection of DNA from noncanonical purine base analogs.

  3. Fair Electronic Cash Based on Double Signatures

    Institute of Scientific and Technical Information of China (English)

    陈晓峰; 王常杰; 王育民

    2002-01-01

    In order to decrease crimes such as money laundering, blackmailing etc. inelectronic cash systems, fair electronic cash has been a major focus of academic research inelectronic commence. When a bank finds some dubious cash or owner, the trusted entity ortrustee can help him to revoke the anonymity of the cash. In the previous protocols, the trusteeknows all the information of the cash whether he is trusted or not, that is, he can trace the useror cash unconditionally. Furthermore, the dishonest trustee may deceive a user, which meansthat he may withdraw cash while tracing other users. Such cases are unfair to the honest users.A new fair electronic cash protocol based on untrustworthy trustees is proposed in thispaper. The key idea is that the coin structure should include the signatures of both the trusteeand the bank so that the trustee shares the information of the cash with the bank, while we donot use the secret sharing scheme. In contrast with the previous protocols, neither the trusteenor the bank can trace the money without the help of the other entity. In this way, the privacyof the user is protected furthest. Also, the trustee is off-line in the protocol, which meansthat he will not be involved in withdrawing the cash. Therefore, the protocol is efficient forimplementation.

  4. Study of effect of gate-length downscaling on the analog/RF performance and linearity investigation of InAs-based nanowire Tunnel FET

    Science.gov (United States)

    Biswal, Sudhansu Mohan; Baral, Biswajit; De, Debashis; Sarkar, Angsuman

    2016-03-01

    In this paper, we present a simulation study to report the effect of gate-length downscaling on the analog/RF performance and linearity investigation of InAs-based nanowire (NW) Tunnel FET (TFET). The different RF/analog and linearity figure of merits such as gm, RO, gm*RO, fT, fmax, GBW and 1-dB compression point of a NW TFET are extracted and the influence of gate-length downscaling on these parameters is analyzed. The RF/analog performance parameters obtained from InAs TFET is compared with an InAs MOSFET of identical dimension. Results reveal that superior RF and Linearity performance was obtained with gate-length downscaling for both devices under consideration. However, advantages of achieving improved RF performance with gate-length downscaling diminishes in terms of poor analog performance with gate-length downscaling for both the devices. This clearly indicates a trade-off between the analog and RF performance of a down-scaled InAs-based NW TFET and MOSFET. The results reveal that InAs TFET provides better fT, fmax and linearity performance in the saturation region than its MOSFET counterpart. It provides a reasonable RO, gm*RO at lower values of gate-overdrive voltage as compared to the InAs MOSFET. Therefore, this paper concludes that InAs NW TFETs have enormous potential to be a promising contender to the conventional bulk MOSFETs for realization of future generation low-power analog/RF applications.

  5. PC-based analog signal generator for simulated detector signals and arbitrary test waveforms for testing the nuclear instruments

    International Nuclear Information System (INIS)

    This work is performed in cooperation with IAEA-Vienna as a project, proposed as part of Agency's Co-ordinated Research Programme of Development of Computer-based Troubleshooting Tools and Instruments. A convenient way for testing and calibrating modern scientific equipment is to connect the test instruments to a personal computer to get additional feasibilities. This way, all settings for test, measurement and data acquisition functions are done by means of PC and are controlled by software drivers. This multifunctional spectrometric pulse generator is able to characterize different parts of high-resolution nuclear spectroscopy chain (preamplifier, amplifier, analog to digital converter, multichannel analyzer) as well as the whole chain. For this it generates periodic or random pulses with shape, time and amplitude specifications controlled by PC. Characteristics such as integral linearity, differential linearity, dead time, rate channel shifting and others will be easily determined. The block diagram of the multifunctional spectrometric generator is shown. The main sections are: PC-interface, control registers and command generation; PC-controlled periodic and random logic pulse oscillators; PC-controlled delay and width of periodic or random logic pulses; constant and ultra-linear ramp references for spectrometric pulse generation; generation of the tail and flat top pulses with PC-controlled amplitude and decay time; semi-gaussian pulse generation, polarity inverter and output amplifier. The specifications for generated signal correspond to: shape, time specifications and amplitude size. (author)

  6. Analysis by NASA's VESGEN Software of Vascular Branching in the Human Retina with a Ground-Based Microgravity Analog

    Science.gov (United States)

    Parsons-Wingerter, Patricia; Vyas, Ruchi J.; Raghunandan, Sneha; Vu, Amanda C.; Zanello, Susana B.; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco

    2016-01-01

    Significant risks for visual impairment were discovered recently in astronauts following spaceflight, especially after long-duration missions.1 We hypothesize that microgravity-induced fluid shifts result in pathological changes within the retinal vasculature that precede visual and other ocular impairments. We therefore are analyzing retinal vessels in healthy subjects with NASA's VESsel GENeration Analysis (VESGEN) software2 before and after head-down tilt (HDT), a ground-based microgravity analog For our preliminary study of masked images, two groups of venous trees with and without small veins (G=7) were clearly identified by VESGEN analysis. Upon completing all images and unmasking the subject status of pre- and post- HDT, we will determine whether differences in the presence or absence of small veins are important correlates, and perhaps reliable predictors, of other ocular and physiological adaptations to prolonged HDT and microgravity. Greater peripapillary retinal thickening was measured following 70-day HDT bed rest than 14-day HDT bed rest, suggesting that time of HDT may increase the amount of optic disc swelling.3 Spectralis OCT detected retinal nerve fiber layer thickening post HDT, without clinical signs of optic disc edema. Such changes may have resulted from HDT-induced cephalad fluid shifts. Clinical methods for examining adaptive microvascular remodeling in the retina to microgravity space flight are currently not established.

  7. Photonic compressive sensing for analog-to-information conversion with a delay-line based microwave photonic filter

    Science.gov (United States)

    Zhu, Zhijing; Chi, Hao; Jin, Tao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2016-07-01

    Compressive sensing (CS) in the photonic domain is highly promising for analog-to-information conversion of sparse signals due to its potential capability of high input bandwidth and digitization with sub-Nyquist sampling. In this paper, we suggest that the concept of delay-line based microwave photonic filter be used in photonic CS to realize the low-pass filtering (LPF) function which is required in CS. A microwave photonic filter (MPF) with a dispersive element and fiber delay lines is applied in photonic CS to achieve better performance and flexibility. In the approach, the input radio-frequency signal and the pseudorandom bit sequence (PRBS) are modulated on a multi-wavelength optical carrier and propagate through a dispersive element. The modulated optical signal is split into multiple channels with tunable delay lines. The multiple wavelengths, dispersive element and multiple channels constitute a reconfigurable low-pass microwave filter. Experiment and simulations are presented to demonstrate the feasibility and potentials of this approach.

  8. A 97 dB dynamic range CSA-based readout circuit with analog temperature compensation for MEMS capacitive sensors

    International Nuclear Information System (INIS)

    This paper presents a charge-sensitive-amplifier (CSA) based readout circuit for capacitive microelectro-mechanical-system (MEMS) sensors. A continuous-time (CT) readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits. An operational trans-conductance amplifier (OTA) structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal. An analog temperature compensation method is proposed, which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity. The chip is designed and implemented in a 0.35 μm CMOS process and is 2.1 × 2.1 mm2 in area. The measurement shows that the readout circuit achieves 0.9 aF / √Hz capacitive resolution, 97 dB dynamic range in 100 Hz signal bandwidth, and 0.8 mV/fF sensitivity with a temperature drift of 35 ppm/°C after optimized compensation. (semiconductor integrated circuits)

  9. Potential applications of curcumin and its novel synthetic analogs and nanotechnology-based formulations in cancer prevention and therapy

    Directory of Open Access Journals (Sweden)

    Batra Surinder K

    2011-08-01

    Full Text Available Abstract Curcumin has attracted great attention in the therapeutic arsenal in clinical oncology due to its chemopreventive, antitumoral, radiosensibilizing and chemosensibilizing activities against various types of aggressive and recurrent cancers. These malignancies include leukemias, lymphomas, multiple myeloma, brain cancer, melanoma and skin, lung, prostate, breast, ovarian, liver, gastrointestinal, pancreatic and colorectal epithelial cancers. Curcumin mediates its anti-proliferative, anti-invasive and apoptotic effects on cancer cells, including cancer stem/progenitor cells and their progenies, through multiple molecular mechanisms. The oncogenic pathways inhibited by curcumin encompass the members of epidermal growth factor receptors (EGFR and erbB2, sonic hedgehog (SHH/GLIs and Wnt/β-catenin and downstream signaling elements such as Akt, nuclear factor-kappa B (NF-κB and signal transducers and activators of transcription (STATs. In counterbalance, the high metabolic instability and poor systemic bioavailability of curcumin limit its therapeutic efficacy in human. Of great therapeutic interest, the selective delivery of synthetic analogs or nanotechnology-based formulations of curcumin to tumors, alone or in combination with other anticancer drugs, may improve their chemopreventive and chemotherapeutic efficacies against cancer progression and relapse. Novel curcumin formulations may also be used to reverse drug resistance, eradicate the total cancer cell mass and improve the anticarcinogenic efficacy of the current anti-hormonal and chemotherapeutic treatments for patients with various aggressive and lethal cancers.

  10. Analog Testing of Operations Concepts for Integration of an Earth-Based Science Team During Human Exploration of Mars

    Science.gov (United States)

    Chappell, Steven P.; Beaton, Kara H.; Graff, Trevor; Newton, Carolyn; Abercromby, Andrew F.; Gernhardt, Michael L.

    2017-01-01

    NASA Extreme Environment Mission Operations (NEEMO) is an underwater spaceflight analog that allows a true mission-like operational environment and uses buoyancy effects and added weight to simulate different gravity levels. A mission was undertaken in 2016, NEEMO 21. The mission was performed at the Aquarius undersea research habitat. During the mission, the effects of varying operations concepts on representative communication latencies associated with Mars missions were studied. Six subjects were weighed out to simulate near-zero or partial gravity and evaluated different operations concepts for integration and management of a simulated Earth-based science team (ST) to provide input and direction during exploration activities. Exploration traverses were planned in advance based on precursor data collected. Subjects completed science-related tasks including pre-sampling surveys and marine science-based sampling as a portion of their tasks on saturation dives up to 4 hours in duration that were to simulate extravehicular activity (EVA) on Mars. A one-way communication latency of 15 minutes between space and mission control was simulated throughout the missions. Objective data included task completion times, total EVA times, crew idle time, translation time, SBT assimilation time (defined as time available for ST to discuss data/imagery after it has been collected, in addition to the time taken to watch imagery and listen to audio streaming over latency). Subjective data included acceptability, simulation quality, capability assessment ratings, and comments. Results were collected and will be presented on the acceptability of the operations concepts studied and which capabilities are the most enabling/enhancing in the operations concept. Discussion is presented on the importance of designing EVA timelines to account for the length of the task, level of interaction with the ground that is required/desired, and communication latency.

  11. Analog Delta-Back-Propagation Neural-Network Circuitry

    Science.gov (United States)

    Eberhart, Silvio

    1990-01-01

    Changes in synapse weights due to circuit drifts suppressed. Proposed fully parallel analog version of electronic neural-network processor based on delta-back-propagation algorithm. Processor able to "learn" when provided with suitable combinations of inputs and enforced outputs. Includes programmable resistive memory elements (corresponding to synapses), conductances (synapse weights) adjusted during learning. Buffer amplifiers, summing circuits, and sample-and-hold circuits arranged in layers of electronic neurons in accordance with delta-back-propagation algorithm.

  12. An Internet Based Anonymous Electronic Cash System

    OpenAIRE

    Israt Jahan; Mohammad Zahidur Rahman; K M Akkas Ali; Israt Jerin

    2015-01-01

    There is an increase activity in research to improve the current electronic payment system which is parallel with the progress of internet. Electronic cash system is a cryptographic payment system which offers anonymity during withdrawal and purchase. Electronic cash displays serial numbers which can be recorded to allow further tracing. Contrary to their physical counterparts, e-cash have an inherent limitation; they are easy to copy and reuse (double-spending). An observer is a tamper-resis...

  13. Entanglement-assisted electron microscopy based on a flux qubit

    OpenAIRE

    Okamoto, Hiroshi; Nagatani, Yukinori

    2013-01-01

    A notorious problem in high-resolution biological electron microscopy is radiation damage to the specimen caused by probe electrons. Hence, acquisition of data with minimal number of electrons is of critical importance. Quantum approaches may represent the only way to improve the resolution in this context, but all proposed schemes to date demand delicate control of the electron beam in highly unconventional electron optics. Here we propose a scheme that involves a flux qubit based on a radio...

  14. Using aeroelastic structures with nonlinear switching electronics to increase potential energy yield in airflow: investigating analog control circuitry for automated peak detection

    Science.gov (United States)

    Mihalca, Alexander G.; Drosinos, Jonathan G.; Grayson, Malika; Garcia, Ephrahim

    2015-03-01

    Bending piezoelectric transducers have the ability to harvest energy from aeroelastic vibrations induced by the ambient airflow. Such harvesters can have useful applications in the operation of low power devices, and their relatively small size makes them ideal for use in urban environments over civil infrastructure. One of the areas of focus regarding piezoelectric energy harvesting is the circuit topology used to store the harvested power. This study aims to further investigate the increase in potential energy yield from the piezoelectric harvester by optimizing the circuitry connecting the piezoelectric transducer and the power storage interface. When compared to an optimal resistive load case, it has been shown that certain circuit topologies, specifically synchronized switching and discharging to a storage capacitor through an inductor (SSDCI), can increase the charging power by as much as 400% if the circuit is completely lossless. This paper proposes a strategy for making a self-sufficient SSDCI circuit capable of peak detection for the synchronized switching using analog components. Using circuit simulation software, the performance of this proposed self-sufficient circuit is compared to an ideal case, and the effectiveness of the self-sufficient circuit strategy is discussed based on these simulation results. Further investigation of a physical working model of the new circuit proposal will be developed and experimental results of the circuit's performance obtained and compared to the estimated performance from the model.

  15. High-energy attosecond nanoplasmonic-based electron gun

    Science.gov (United States)

    Greig, S. R.; Elezzabi, A. Y.

    2016-03-01

    We present the design of an ultrafast conical lens based nanoplasmonic electron gun. Through excitation with a radially polarized laser pulse, and a combination of magnetostatic and spatial filtering, high energy electron packets with attosecond durations can be achieved.

  16. Conducting polymer based biomolecular electronic devices

    Indian Academy of Sciences (India)

    B D Malhotra; Rahul Singhal

    2003-08-01

    Biomolecular electronics is rapidly evolving from physics, chemistry, biology, electronics and information technology. Organic materials such as proteins, pigments and conducting polymers have been considered as alternatives for carrying out the functions that are presently being performed by semiconductor silicon. Conducting polymers such as polypyrroles, polythiophenes and polyanilines have been projected for applications for a wide range of biomolecular electronic devices such as optical, electronic, drug-delivery, memory and biosensing devices. Our group has been actively working towards the application of conducting polymers to Schottky diodes, metal–insulator–semiconductor (MIS) devices and biosensors for the past 10 years. This paper is a review of some of the results obtained at our laboratory in the area of conducting polymer biomolecular electronics.

  17. Electronic structure of hybrid interfaces for polymer-based electronics

    International Nuclear Information System (INIS)

    The fundamentals of the energy level alignment at anode and cathode electrodes in organic electronics are described. We focus on two different models that treat weakly interacting organic/metal (and organic/organic) interfaces: the induced density of interfacial states model and the so-called integer charge transfer model. The two models are compared and evaluated, mainly using photoelectron spectroscopy data of the energy level alignment of conjugated polymers and molecules at various organic/metal and organic/organic interfaces. We show that two different alignment regimes are generally observed: (i) vacuum level alignment, which corresponds to the lack of vacuum level offsets (Schottky-Mott limit) and hence the lack of charge transfer across the interface, and (ii) Fermi level pinning where the resulting work function of an organic/metal and organic/organic bilayer is independent of the substrate work function and an interface dipole is formed due to charge transfer across the interface. We argue that the experimental results are best described by the integer charge transfer model which predicts the vacuum level alignment when the substrate work function is above the positive charge transfer level and below the negative charge transfer level of the conjugated material. The model further predicts Fermi level pinning to the positive (negative) charge transfer level when the substrate work function is below (above) the positive (negative) charge transfer level. The nature of the integer charge transfer levels depend on the materials system: for conjugated large molecules and polymers, the integer charge transfer states are polarons or bipolarons; for small molecules' highest occupied and lowest unoccupied molecular orbitals and for crystalline systems, the relevant levels are the valence and conduction band edges. Finally, limits and further improvements to the integer charge transfer model are discussed as well as the impact on device design. (topical review)

  18. Quantum-based electronic devices and systems selected topics in electronics and systems, v.14

    CERN Document Server

    Dutta, Mitra

    1998-01-01

    This volume includes highlights of the theories and experimental findings that underlie essential phenomena occurring in quantum-based devices and systems as well as the principles of operation of selected novel quantum-based electronic devices and systems. A number of the emerging approaches to creating new types of quantum-based electronic devices and systems are also discussed.

  19. Terrestrial Spaceflight Analogs: Antarctica

    Science.gov (United States)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  20. Isoquinoline-based analogs of the cancer drug clinical candidate tipifarnib as anti-Trypanosoma cruzi agents

    OpenAIRE

    Chennamaneni, Naveen Kumar; Arif, Jenifer; Buckner, Frederick S.; Gelb, Michael H

    2009-01-01

    We developed a synthetic route to prepare isoquinoline analogs of the cancer drug clinical candidate tipifarnib. We show that these compounds kill Trypanosoma cruzi amastigotes grown in mammalian host cells at concentrations in the low nanomolar range. These isoquinolines represent new leads for the development of drugs to treat Chagas disease.

  1. Analog and VLSI circuits

    CERN Document Server

    Chen, Wai-Kai

    2009-01-01

    Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.

  2. An Internet Based Anonymous Electronic Cash System

    Directory of Open Access Journals (Sweden)

    Israt Jahan

    2015-04-01

    Full Text Available There is an increase activity in research to improve the current electronic payment system which is parallel with the progress of internet. Electronic cash system is a cryptographic payment system which offers anonymity during withdrawal and purchase. Electronic cash displays serial numbers which can be recorded to allow further tracing. Contrary to their physical counterparts, e-cash have an inherent limitation; they are easy to copy and reuse (double-spending. An observer is a tamper-resistant device, issued by the Internet bank, which is incorporated with the Internet user’s computer that prevents double-spending physically, i.e., the user has no access to her e-cash and therefore he cannot copy them. In this paper, we shall present an anonymous electronic cash scheme on the internet which incorporates tamper-resistant device with user-module.

  3. Introducing the ELMCIP Electronic Literature Knowledge Base

    OpenAIRE

    Rettberg, Scott

    2013-01-01

    Focusing on a particular creative community, of electronic literature practitioners, the central research question of the ELMCIP collaborative research project is how creative communities of practitioners form within transnational and transcultural contexts, within a globalised and distributed communications environment. We seek to gain insight into and understanding of the social effects and manifestations of creativity. Our research seeks to exploit the characteristics of electronic literat...

  4. Lumped time-delay compensation scheme for coding synchronization in the nonlinear spectral quantization-based all-optical analog-to-digital conversion

    OpenAIRE

    Kang, Zhe; Yuan, Jinhui; Wu, Qiang; WANG, Tao; Li, Sha; Sang, Xinzhu; Yu, Chongxiu; Farrell, Gerald

    2013-01-01

    In this paper, we propose a novel lumped time-delay compensation scheme for the all-optical analog-to-digital conversion based on soliton self-frequency shift and optical interconnection techniques. By inserting a segment of negative dispersion fiber between the quantization and the coding module, the time delay of different quantized pulses can be accurately compensated with a simple structure compared to the multiple time-delay lines. The simulation results show that the coding pulses...

  5. Science Teachers' Analogical Reasoning

    Science.gov (United States)

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-08-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to introduce analogies in their lessons. Both aspects have been discussed in the literature in the last few decades. However, almost nothing is known about how teachers draw their own analogies for instructional purposes or, in other words, about how they reason analogically when planning and conducting teaching. This is the focus of this paper. Six secondary teachers were individually interviewed; the aim was to characterize how they perform each of the analogical reasoning subprocesses, as well as to identify their views on analogies and their use in science teaching. The results were analyzed by considering elements of both theories about analogical reasoning: the structural mapping proposed by Gentner and the analogical mechanism described by Vosniadou. A comprehensive discussion of our results makes it evident that teachers' content knowledge on scientific topics and on analogies as well as their pedagogical content knowledge on the use of analogies influence all their analogical reasoning subprocesses. Our results also point to the need for improving teachers' knowledge about analogies and their ability to perform analogical reasoning.

  6. Flexible, fpga-based electronics for modular robots

    DEFF Research Database (Denmark)

    Brandt, David; Larsen, Jørgen Christian; Christensen, David Johan;

    2008-01-01

    In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays (FPGAs). The immediate advantage of using FPGAs is that some of the module’s electronics can be moved into the FPGA, thereby the number of components can be reduced. In the case...... the FPGA and therefore integrate task-specific electronics without physically changing the electronics or we can reconfigure the electronics for specific tasks. The disadvantages of an FPGA-based design include the cost of FPGAs, the extra layer of complexity in programming, and a limited increase in power...... consumption compared to micro-controllers. However, overall FPGAs make the electronics of modular robots more flexible and therefore may make them more suitable for real applications. AB - In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays...

  7. Practical Research of Electronic Transformer Based on Interpolation Algorithm

    OpenAIRE

    Fu Yang; Ji Hui; Li Zhenkun

    2013-01-01

    As a result of the adoption of new photovoltaic technology, electronic transformers have great advantages compared with traditional electromagnetic type, such as anti-saturated, high linearity, compact and lightweight etc. The working principle of sensing head of electronic current/voltage transformers is introduced in the paper. The causes of phase error in electronic transformer are analyzed. And a set of phase compensation methods based on the signal transfer principle of electronic transf...

  8. Linac based free-electron laser

    International Nuclear Information System (INIS)

    A basic treatment of the principle of the linac-driven free-electron laser (FEL) is given. The first part of the paper describes the FEL in low-gain approximation, and in the second part the high-gain FEL theory is given. The majority of the treatment describes FELs in one dimensional approximation, neglecting effects by diffraction of radiation and by electron beam emittance. Only in the final section a few remarks on these issues are given. The ambition of the paper is by no means any progress in FEL theory but a clear presentation of basic FEL theory concepts with explicit derivation of the formulae from first principles. (orig.)

  9. Multi-scale entropy analysis of VR-based analog-digital system of the operator mental workload

    International Nuclear Information System (INIS)

    In the past, serious accidents of nuclear power plant usually had relation with the negligence, error handling and wrong decisions of operators. Therefore, to understand and be able to measure mental workload levels of operators are significant for safety issues in the nuclear power plant, especially when operators face emergency conditions. Therefore, this study is to determine the physiological indicators to measure the operator in the task of mental workload. This paper was to use electrocardiogram (ECG) measurements, to collect the RR-Interval data; heart rate variability (HRV) to analysis the complexity of the operator. After importing the data to calculate heart rate variability of complexity analysis, it can help us to understand the operator for the analog-digital platform adaptation. The virtual analog-digital nuclear plant control room is built using a 3D game development tool called Unity3D. (author)

  10. In Vitro Biologic Activities of the Antimicrobials Triclocarban, Its Analogs, and Triclosan in Bioassay Screens: Receptor-Based Bioassay Screens

    OpenAIRE

    Ahn, Ki Chang; Zhao, Bin; Chen, Jiangang; Cherednichenko, Gennady; Sanmarti, Enio; Denison, Michael S.; Lasley, Bill; Pessah, Isaac N; Kültz, Dietmar; Chang, Daniel P.Y.; Gee, Shirley J.; Hammock, Bruce D.

    2008-01-01

    Background Concerns have been raised about the biological and toxicologic effects of the antimicrobials triclocarban (TCC) and triclosan (TCS) in personal care products. Few studies have evaluated their biological activities in mammalian cells to assess their potential for adverse effects. Objectives In this study, we assessed the activity of TCC, its analogs, and TCS in in vitro nuclear-receptor–responsive and calcium signaling bioassays. Materials and methods We determined the biological ac...

  11. Analog simulation of the Josephson effects

    International Nuclear Information System (INIS)

    Analog circuit techniques can be used to advantage to simulate the Josephson effects in a superconductor-insulator-superconductor tunnel junction. Details of an electronic Josephson simulator are presented, and the advantages of analog techniques over their digital counterparts for this application are discussed. The simulation of a Josephson microwave mixer is used as an example

  12. DC characteristics and analog/RF performance of novel polarity control GaAs-Ge based tunnel field effect transistor

    Science.gov (United States)

    Nigam, Kaushal; Kondekar, Pravin; Sharma, Dheeraj

    2016-04-01

    In this paper, for the first time, DC characteristics and analog/RF performance of polarity control GaAs-Ge hetero TFET (GaAs-Ge H-TFET) structure have been analysed, using electrically doped dynamically configurable concept. For this, we have considered a hetero structure with two distinctive gates (Control gate and Polarity gate). Polarity gate induces p+ region at the source side and n+ region at the drain side, instead of relying on the abrupt doping profile at the junctions. Therefore, the fabrication process of the proposed device avoids ion-implantation, photo masking and complicated thermal budget. Hence, it shows high immunity against process variations, doping control issues and random dopant fluctuations (RDF). In order to optimize the device performance, interfacing of III-V groups materials with IV group semiconductor is done for hetero-junction. The introduction of hetero-junction and band gap engineering offer higher ION/IOFF ratio (5.1 × 1012), steep sub-threshold slope (18 mV/decade) and significantly change in analog/RF performance. The analog/RF figures of merit are analysed in term of transconductance (gm), output conductance (gds), gate to source capacitance (Cgs), gate to drain capacitance (Cgd), cutoff frequency (fT) and gain bandwidth (GBW) product. The proposed work would be beneficial for low power high frequency applications. The simulation results presented in this paper were carried out by using 2-D ATLAS.

  13. 脉冲控制忆阻模拟存储器%Analog Memory Based on Pulse Controlled Memristor

    Institute of Scientific and Technical Information of China (English)

    胡小方; 段书凯; 王丽丹; 李传东

    2011-01-01

    In this paper, the charge-controlled and flux-controlled memristor mathematical models are derived detailedly. The continuously variable conductance and memory properties of memristors are researched. An implementation scheme for analog memory using pulse controlled memristors is proposed, and its effectiveness is verified through theoretical analysis and simulation experiments. With crossbar array structure, the scheme is expected to achieve large-scale analog storage arrays, which may greatly promote the development of artificial neural networks and analog computers.%推导了忆阻器的电荷控制和磁通量控制数学模型,在该基础上研究了其电导状态连续可变的性质和记忆功能.提出了用脉冲控制忆阻器实现模拟信息存储的方案,通过理论分析、实验仿真验证了方案的有效性.结合交叉阵列结构,该方案有望实现大规模模拟存储阵列,推进人工神经网络和模拟式计算机的发展.

  14. Animation Based Learning of Electronic Devices

    Science.gov (United States)

    Gero, Aharon; Zoabi, Wishah; Sabag, Nissim

    2014-01-01

    Two-year college teachers face great difficulty when they teach the principle of operation of the bipolar junction transistor--a subject which forms the basis for electronics studies. The difficulty arises from both the complexity of the device and by the lack of adequate scientific background among the students. We, therefore, developed a unique…

  15. Implementation of a 10.24 GS/s 12-bit Optoelectronics Analog-to- Digital Converter Based on a Polyphase Demultiplexing Architecture

    Directory of Open Access Journals (Sweden)

    C. Villa-Angulo

    2013-01-01

    Full Text Available In this paper we present the practical implementation of a high-speed polyphase sampling and demultiplexingarchitecture for optoelectronics analog-to-digital converters (OADCs. The architecture consists of a one-stage divideby-eight decimator circuit where optically-triggered samplers are cascaded to sample an analog input signal, anddemultiplex different phases of the sampled signal to yield low data rate for electronic quantization. Electrical-in toelectrical-out data format is maintained through the sampling, demultiplexing and quantization processes of thearchitecture thereby avoiding the need for electrical-to-optical and optical-to-electrical signal conversions. Weexperimentally demonstrate a 10.24 giga samples per second (GS/s, 12-bit resolution OADC system comprising theoptically-triggered sampling circuits integrated with commercial electronic quantizers. Measurements performed on theOADC yielded an effective bit resolution (ENOB of 10.3 bits, spurious free dynamic range (SFDR of -32 dB andsignal-to-noise and distortion ratio (SNDR of 63.7 dB.

  16. Code synchronization based on lumped time-delay compensation scheme with a linearly chirped fiber Bragg grating in all-optical analog-to-digital conversion

    International Nuclear Information System (INIS)

    We propose a novel lumped time-delay compensation scheme for all-optical analog-to-digital conversion based on soliton self-frequency shift and optical interconnection techniques. A linearly chirped fiber Bragg grating is optimally designed and used to compensate for the entire time-delays of the quantized pulses precisely. Simulation results show that the compensated coding pulses are well synchronized with a time difference less than 3.3 ps, which can support a maximum sampling rate of 151.52 GSa/s. The proposed scheme can efficiently reduce the structure complexity and cost of all-optical analog-to-digital conversion compared to the previous schemes with multiple optical time-delay lines. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. Quality Defect Management Ability Evaluation of Enterprises Based on Projection Pursuit and Optimal Segmentation: Explanatory Framework of Medical Analogy and Metaphor Thought

    Directory of Open Access Journals (Sweden)

    Liping Shi

    2013-01-01

    Full Text Available This study follows medical analogy and metaphor thought, based on the similarities between quality defect of enterprises and disease in the medical field, analogies and metaphors the management process of disease in the medical field with the management process of quality defect of enterprises, refers to relevant literatures to establish quality defect management ability evaluation indicators system, the system includes quality defect diagnosis ability, quality defect governance ability and subsequent improvement ability of quality defect governance. Set typical thirty enterprises of Heilongjiang Province as an example, use projection pursuit to evaluate quality defect management ability of enterprises, employ optimal segmentation method to cluster and optimize the evaluation results. Study results will provide theoretical foundations for managing quality defect of enterprises and enhancing quality defect management ability.

  18. The Roads to LPA Based Free Electron Laser

    OpenAIRE

    Zhu, Xiongwei

    2014-01-01

    In this paper, we simply outline the present status of the free electron laser and the laser plasma based accelerator, and we simply discuss the potential possible roads appearing in the accelerator community to use the laser plasma based accelerator into the field of the free electron laser.

  19. A digital-analog hybrid random numb er generator based on memristor%基于忆阻器的数模混合随机数发生器∗

    Institute of Scientific and Technical Information of China (English)

    袁泽世; 李洪涛; 朱晓华

    2015-01-01

    integral system. In this paper, a novel digital-analog hybrid chaotic system with only one analog device is constructed for the pro-duction of RN. The chosen analog device is a generalized memristor consisting of a diode bridge and a parallel RC filter. Memristor is the fourth fundamental electronic component which has provoked extensive researches since the suc-cessful realization by Stan Williams’s group at HP Labs in 2008. The paper is arranged as follows. Firstly, a generalized memristor realized by a memristive circuit is introduced and its basic properties are given. Then the block diagram of the digital-analog hybrid system based on a single memristor feedback is depicted, and the mathematical model of the system is derived from the block diagram. Thirdly, the simple Logistic map is applied to the hybrid model and its dynamic behaviors are simulated and compared with those from the ideal Logistic before a more complex two-way coupled saw tooth map is applied to the same simulation, verifying the effectiveness of the proposed hybrid system. Finally, the complex coupled map is applied to the practical circuit producing RN which passes the NIST test suite smoothly. The hybrid system has the following advantages: firstly, the introduction of the analog memristor is able to over-come the dynamical degradation in a digital system, avoiding the limited word length effect essentially. Secondly, the least analog device alleviates the sensibility to parameters and the restriction on bit rate in analog systems, ensuring that the hybrid system is robust. Thirdly, the system structure can be easily integrated into a relevant system. By designing the circuits of the system, the field programmable logic gate array of digital part can be used to realize chaotic map while the single memristor acts as a feedback to the digital part. The experimental results show that the novel hybrid system is insensitive to the variations of circuit parameters and the produced RN is of great

  20. Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials

    Science.gov (United States)

    Shah Mohammadi, Maziar

    Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It

  1. 模拟电子技术课程教学改革研究与实践%Research and Practice on the Teaching Reform of Analog Electronic Technology Course

    Institute of Scientific and Technical Information of China (English)

    卢翠珍; 陆冬妹

    2016-01-01

    For courses of electronic information engineering ma-jor, Analog Electronic Technology course is a relatively difficult one with more content, therefore, many students feel it difficult to learn the course and their academic performance is affected by the situation to a certain extent. This paper briefly analyzes the teaching reform of Analog Electronic Technology course, hoping to provide some help for electronic information engineer-ing undergraduates to improve their academic performance.%对电子信息工程专业的课程来说,模拟电子技术课程的难度较大、课程内容较多,因此,有很多学生在学习这门课程的过程中感到压力大,同时对于学习成绩也造成了一定的影响。文章针对模拟电子技术课程的教学改革进行了简单的分析,以期为提高电子信息工程专业本科学生的学生成绩提供有力帮助。

  2. Neuromimetic Circuits with Synaptic Devices Based on Strongly Correlated Electron Systems

    Science.gov (United States)

    Ha, Sieu D.; Shi, Jian; Meroz, Yasmine; Mahadevan, L.; Ramanathan, Shriram

    2014-12-01

    Strongly correlated electron systems such as the rare-earth nickelates (R NiO3 , R denotes a rare-earth element) can exhibit synapselike continuous long-term potentiation and depression when gated with ionic liquids; exploiting the extreme sensitivity of coupled charge, spin, orbital, and lattice degrees of freedom to stoichiometry. We present experimental real-time, device-level classical conditioning and unlearning using nickelate-based synaptic devices in an electronic circuit compatible with both excitatory and inhibitory neurons. We establish a physical model for the device behavior based on electric-field-driven coupled ionic-electronic diffusion that can be utilized for design of more complex systems. We use the model to simulate a variety of associate and nonassociative learning mechanisms, as well as a feedforward recurrent network for storing memory. Our circuit intuitively parallels biological neural architectures, and it can be readily generalized to other forms of cellular learning and extinction. The simulation of neural function with electronic device analogs may provide insight into biological processes such as decision making, learning, and adaptation, while facilitating advanced parallel information processing in hardware.

  3. Neural network based electron identification in the ZEUS calorimeter

    International Nuclear Information System (INIS)

    We present an electron identification algorithm based on a neural network approach applied to the ZEUS uranium calorimeter. The study is motivated by the need to select deep inelastic, neutral current, electron proton interactions characterized by the presence of a scattered electron in the final state. The performance of the algorithm is compared to an electron identification method based on a classical probabilistic approach. By means of a principle component analysis the improvement in the performance is traced back to the number of variables used in the neural network approach. (orig.)

  4. Prediction of correlation between two-phase natural circulation flows in heated and unheated channels of a parallel channel system - based on electrical analogy

    International Nuclear Information System (INIS)

    A common characteristic of many industrial two-phase natural circulation systems is the presence of a large number of parallel boiling channels. Sensitivity of the steady state behavior of such a two-phase natural circulation system to different system parameters has many implications vis-a-vis performance of the system as per the design intent under various operating conditions. Experimental studies were carried out, to study the characteristics of a low pressure two-phase natural circulation system having ten transparent parallel channels with their individual heat sources. In view of its particular significance in nuclear industry, a special system condition with zero power in one of the parallel channels was also studied. The flow in the unheated channel and that in the heated channels were observed to be strongly interdependent in their sensitivity to downcomer resistance. A simple theory based on electrical analogy has been developed to predict the hydraulic behavior in such a system. Agreement between the theoretical predictions and the experimental observations has been found to be good. This article describes the experimentally observed phenomenon, the electrical analogy and the comparison between the experimental data and the analogical predictions. (orig.)

  5. Selection of the optimum combination of responses for Wave Buoy Analogy - An approach based on local sensitivity analysis

    DEFF Research Database (Denmark)

    Montazeri, Najmeh; Nielsen, Ulrik Dam; Jensen, Jørgen Juncher

    2016-01-01

    One method to estimate the wave spectrum onboard ships is to use measured ship responses. In this method, known also as Wave Buoy Analogy, amongst various responses that are available from sensor measurements, a couple of responses (at least three) are usually utilized. Selec-tion of the best...... combination of ship responses is important. Optimally, this selection should not be implemented manually in onboard applications. Therefore, availability of an automatic response selection procedure would be a great advantage for decision support. In this paper, a local sensitivity analysis is applied...

  6. A Mixed Analog-Digital Radiation Hard Technology for High Energy Physics Electronics: DMILL~(Durci~Mixte~sur~Isolant~Logico-Lineaire)

    CERN Multimedia

    Lugiez, F; Leray, J; Rouger, M; Fourches, N T; Musseau, O; Potheau, R

    2002-01-01

    %RD29 %title\\\\ \\\\Physics experiments under preparation with the future LHC require a fast, low noise, very rad-hard (>10 Mrad and >10$^{14}$ neutron/cm$^{2}$), mixed analog-digital microelectronics VLSI technology.\\\\ \\\\The DMILL microelectronics technology (RD29) was developed between 1990 and 1995 by a Consortium gathering the CEA and the firm Thomson-TCS, with the collaboration of IN2P3. The goal of the DMILL program, which is now completed, was to provide the High Energy Physics community, space industry, nuclear industry, and other applications, with an industrial very rad-hard mixed analog-digital microelectronics technology.\\\\ \\\\DMILL integrates mixed analog-digital very rad-hard (>10 Mrad and >10$^{14}$ neutron/cm$^{2}$) vertical bipolar, 0.8 $\\mu$m CMOS and 1.2 $\\mu$m PJFET transistors. Its SOI substrate and its dielectric trenches strongly reduce SEU sensitivity and completely eliminate any possibility of latch-up. Its four transistors are optimized to obtain low-noise features. DMILL also integrates...

  7. Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system.

    Science.gov (United States)

    Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

    2014-03-01

    Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper. PMID:24689606

  8. Embedded Based Electronic Voting Machine Using Password

    Directory of Open Access Journals (Sweden)

    Varkala Vinay,

    2015-04-01

    Full Text Available The Electronic voting machine plays a key role in elections. The Earlier EVM’S needs more man power, time and mislead the voting scenario due to influence of local people vote and after voting the other may vote only after the Password is set then the system gets ready to accept the polling. After completion of the polling we may make the system to reset .If the person is authenticated then the vote is issued and the polling process is done using buzzer system, else that denies the process. At every regular intervals of time the polled votes are recorded and give the count that how many votes are casted through LCD. This system gives an efficient way to conduct elections and display the results on the same day.

  9. Synaptic devices based on purely electronic memristors

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ruobing [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Li, Jun; Zhuge, Fei, E-mail: zhugefei@nimte.ac.cn, E-mail: h-cao@nimte.ac.cn; Zhu, Liqiang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Cao, Hongtao, E-mail: zhugefei@nimte.ac.cn, E-mail: h-cao@nimte.ac.cn; Fu, Bing; Li, Kang [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2016-01-04

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs.

  10. Synaptic devices based on purely electronic memristors

    International Nuclear Information System (INIS)

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs

  11. Graph-based linear scaling electronic structure theory

    CERN Document Server

    Niklasson, Anders M N; Negre, Christian F A; Cawkwell, Marc J; Swart, Pieter J; Mohd-Yusof, Jamal; Germann, Timothy C; Wall, Michael E; Bock, Nicolas; Djidjev, Hristo

    2016-01-01

    We show how graph theory can be combined with quantum theory to calculate the electronic structure of large complex systems. The graph formalism is general and applicable to a broad range of electronic structure methods and materials, including challenging systems such as biomolecules. The methodology combines well-controlled accuracy, low computational cost, and natural low-communication parallelism. This combination addresses substantial shortcomings of linear scaling electronic structure theory, in particular with respect to quantum-based molecular dynamics simulations.

  12. Design of simulated nuclear electronics laboratory experiments based on IAEA-TECDOC-530 on pcs

    International Nuclear Information System (INIS)

    In this IAEA project, PK-11089 (Design of Simulated Nuclear Electronics Laboratory Experiments based on IAEA-TECDOC-530 on PCs), a software package consisting of Computer-Simulated Laboratory Experiments on Nuclear Electronics compatible with the IAEA-TECDOC-530 (Nuclear Electronics Laboratory Manual) has been developed in OrCAD 9.0 (an electronic circuit simulation software environment) as a self-training aid. The software process model employed in this project is the Feedback Waterfall model with some Rapid Application Model. The project work is completed in the five phases of the SDLC, (all of them have been fully completed) which includes the Requirement Definition, Phase, System and Software Design, Implementation and Unit testing, Integration and System-testing phase and the Operation and Maintenance phase. A total of 125 circuits are designed in 39 experiments from Power Supplies, Analog circuits, Digital circuits and Multi-channel analyzer sections. There is another set of schematic designs present in the package, which contains faulty circuits. This set is designed for the learners to exercise the troubleshooting. The integration and system-testing phase was carried out simultaneously. The Operation and Maintenance phase has been implemented by accomplishing it through some trainees and some undergraduate engineering students by allowing them to play with the software independently. (author)

  13. On a possibility of construction of the fast micropower analog-to-digital converter on the base of using charge-coupled devices

    International Nuclear Information System (INIS)

    A possibility of construction of the fast micropower analog-to-digital converter (ADC) on the base of using the charge-coupled devices (CCD) has been considered, and its comparison with the bit coding ADC has been carried out. The results of the analysis of the ADC of both types revealed the 4-5 times gain over occupied area and supply power for the ADC on the base of CCD as compared to the bit coding ADC. Particular amphasis is placed upon the accuracy of conversion in the ADC on the base of CCD. The spread of the charge detector gain has been shown to influence upon the accuracy of conversion. This undesirable effect appears due to the large CCD gate area spread. Possible ways of avoiding the effects of area spread on the conversion accuracy have been indicated. As a result of the study made is a conclusion on the possibility of designing the 8-bit ADC (without analogous units) on the base of 1x1 mm crystal with a response of about several MHz at energy power unit of about hundreds of milliwatts

  14. A generic converter for experimentation based power electronics learning

    OpenAIRE

    Leite, V; Barbosa, José; Teixeira, H.; Araújo, R.

    2005-01-01

    This paper presents a low cost, modular, configurable and fully protected education tool based on a generic electronic converter to be used by students, providing them with skills regarding power electronics and converters, and enabling them to learn from experience the most important issues concerning DC and AC electric drives.

  15. Using Electronic Resources to Support Problem-Based Learning

    Science.gov (United States)

    Chang, Chen-Chi; Jong, Ay; Huang, Fu-Chang

    2012-01-01

    Students acquire skills in problem solving and critical thinking through the process as well as team work on problem-based learning courses. Many courses have started to involve the online learning environment and integrate these courses with electronic resources. Teachers use electronic resources in their classes. To overcome the problem of the…

  16. 基于GEP的模拟电路系统辨识技术%System Identification of Analog Circuits Based on Gene Expression Programming

    Institute of Scientific and Technical Information of China (English)

    王俊亚; 陈棣湘; 潘孟春

    2011-01-01

    Identifying the mathematical model of the analog circuit through the IO data is the key technology in the model - based fast equipment test method. According to the electrical characteristics of the analog circuit system, we designed R-square-based fitness function, and the selection strategy combined with elitism and roulette. The establishment method of analog circuit system identification based on gene expression programming (GEP) was constituted with the partially mapped crossover operator, the heuristic mutation operator, and the sequence insertion operator. Compared with the MATLAB system identification toolbox, this method can identify not only the system parameter, but also the structure. If you set the suitable identification precision, we can get the theoretical system model via the SISO and MIMO tests.%根据模拟电路系统的输入输出数据辨识,其数学模型是基于模型的装备快速测试方法中的关键技术之一.针对模拟电路系统的特点,设计了基于R-square的适应度函数、基于精英主义和轮盘赌算法的选择策略,采用部分映射、启发式变异算子,提出了一种基于基因表达式编程算法的模拟电路系统辨识方法并进行了系统实现.与MATLAB系统辨识工具箱对比,该方法不仅能够辨识电路系统的参数,而且还能辨识系统的结构.实验表明,通过设置适当的辨识精度,可以得到与理论模型一致的系统模型.

  17. Accumulation of sphingoid bases, the structural sphingoid base analog FTY720 and their phosphorylated metabolites in blood, plasma and decidua of SWV and LMBC mice treated with Fumonisin B1 or FTY720

    Science.gov (United States)

    Fumonisins (FB) are mycotoxins in maize and inhibitors of ceramide synthase (CS). FB1 has been shown to cause neural tube defects (NTD) in mice with the LMBc strain being more sensitive than the SWV or other strains. FTY720 (FTY) is a sphingoid base analog derivative of myriocin, another fungal meta...

  18. Phase-Based Binocular Perception of Motion in Depth: Cortical-Like Operators and Analog VLSI Architectures

    Directory of Open Access Journals (Sweden)

    Silvio P. Sabatini

    2003-06-01

    Full Text Available We present a cortical-like strategy to obtain reliable estimates of the motions of objects in a scene toward/away from the observer (motion in depth, from local measurements of binocular parameters derived from direct comparison of the results of monocular spatiotemporal filtering operations performed on stereo image pairs. This approach is suitable for a hardware implementation, in which such parameters can be gained via a feedforward computation (i.e., collection, comparison, and punctual operations on the outputs of the nodes of recurrent VLSI lattice networks, performing local computations. These networks act as efficient computational structures for embedded analog filtering operations in smart vision sensors. Extensive simulations on both synthetic and real-world image sequences prove the validity of the approach that allows to gain high-level information about the 3D structure of the scene, directly from sensorial data, without resorting to explicit scene reconstruction.

  19. Calibration Base Lines for Electronic Distance Measuring Instruments (EDMI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A calibration base line (CBL) is a precisely measured, straight-line course of approximately 1,400 m used to calibrate Electronic Distance Measuring Instruments...

  20. Multi-modal Registration for Correlative Microscopy using Image Analogies

    OpenAIRE

    Cao, Tian; Zach, Christopher; Modla, Shannon; Powell, Debbie; Czymmek, Kirk; Niethammer, Marc

    2013-01-01

    Correlative microscopy is a methodology combining the functionality of light microscopy with the high resolution of electron microscopy and other microscopy technologies for the same biological specimen. In this paper, we propose an image registration method for correlative microscopy, which is challenging due to the distinct appearance of biological structures when imaged with different modalities. Our method is based on image analogies and allows to transform images of a given modality into...

  1. Electronic Commerce Logistics Network Optimization Based on Swarm Intelligent Algorithm

    Directory of Open Access Journals (Sweden)

    Yabing Jiao

    2013-09-01

    Full Text Available This article establish an efficient electronic commerce logistics operation system to reduce distribution costs and build a logistics network operation model based on around the B2C electronic commerce enterprise logistics network operation system. B2C electronic commerce transactions features in the enterprise network platform. To solve the NP-hard problem this article use hybrid ant colony algorithm, particle swarm algorithm and group swarm intelligence algorithm to get a best solution. According to the intelligent algorithm, design of electronic commerce logistics network optimization system, enter the national 22 electronic commerce logistics network for validation. Through the experiment to verify the optimized logistics cost greatly decreased. This research can help B2C electronic commerce enterprise logistics network to optimize decision-making under the premise of ensuring the interests of consumers and service levels also can be an effective way for enterprises to improve the efficiency of logistics services and reduce operation costs

  2. A Novel Calibrator for Electronic Transformers Based on IEC 61850

    Directory of Open Access Journals (Sweden)

    Baoxiang PAN

    2013-01-01

    Full Text Available It is necessary for electronic transformer to make calibration before putting it into practice. To solve the problems in actual calibration process, a novel electronic transformer calibrator is designed. In principle, this system adopts both the direct method and the difference method, which are two popular methods for electronic transformer calibration, by this way the application of the system is extended with its reliability improved. In the system design, based on virtual instrument technology, LabVIEW and WinPCap toolkit are used to develop the application software, and it is able to calibrate those electronic transformers following the standard of IEC 61850. In the calculation of ratio and phase error based on fast Fourier transform, a new window function is introduced, and thus the accuracy of calibration, influenced by the frequency vibration, is improved. This research provides theoretic support and practical reference to the development of intelligent calibrator for electronic transformers.

  3. Chemical Functionalization Effects on Cubane-Based Chain Electronic Transport

    Directory of Open Access Journals (Sweden)

    Konstantin P. Katin

    2015-01-01

    Full Text Available We report electronic structure calculations in chemically functionalized linear cubane-based chains. The effects of covalent chemical attachments on chain transport properties are examined with nonorthogonal tight-binding model (NTBM considering Landauer-Büttiker formalism. The covalent bonding of even a single-type functional group is shown to considerably alter the conductance of the chain. For similar radical doping density, electronic characteristics are found to range from insulator to narrow-gap semiconductor depending on the nature of the covalent bonding. Therefore it has become possible to tune electronic properties of the cubane-based one-dimensional oligomers by the functionalization for nanoelectronic applications.

  4. Analog to Digital Conversion in Physical Measurements

    OpenAIRE

    Kapitaniak, T.; Zyczkowski, K.; Feudel, U.; Grebogi, C.

    1999-01-01

    There exist measuring devices where an analog input is converted into a digital output. Such converters can have a nonlinear internal dynamics. We show how measurements with such converting devices can be understood using concepts from symbolic dynamics. Our approach is based on a nonlinear one-to-one mapping between the analog input and the digital output of the device. We analyze the Bernoulli shift and the tent map which are realized in specific analog/digital converters. Furthermore, we d...

  5. Controlled cooling of an electronic system based on projected conditions

    Science.gov (United States)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2015-08-18

    Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

  6. Controlled cooling of an electronic system based on projected conditions

    Energy Technology Data Exchange (ETDEWEB)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2016-05-17

    Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

  7. Multilateral Collaborations in Analog Research

    Science.gov (United States)

    Cromwell, R. l.

    2016-01-01

    International collaborations in studies utilizing ground-based space flight analogs are an effective means for answering research questions common to participating agencies. These collaborations bring together worldwide experts to solve important space research questions. By collaborating unnecessary duplication of science is reduced, and the efficiency of analog use is improved. These studies also share resources among agencies for cost effective solutions to study implementation. Recently, NASA has engaged in collaborations with international partners at a variety of analog sites. The NASA Human Exploration Research Analog (HERA) is currently hosting investigator studies from NASA and from the German Space Agency (DLR). These isolation studies will answer questions in the areas of team cohesion, sleep and circadian rhythms, and neurobehavioral correlates to function. Planning for the next HERA campaign is underway as proposal selections are being made from the International Life Sciences Research Announcement (ILSRA). Studies selected from the ILSRA will be conducted across 4 HERA missions in 2017. NASA is planning collaborative studies with DLR at the :envihab facility in Cologne, Germany. Investigations were recently selected to study the effects of 0.5% CO2 exposure over 30 days of bed rest. These studies will help to determine the fidelity of this ground-based analog for studying the visual impairment intracranial pressure syndrome. NASA is also planning a multilateral collaboration at :envihab with DLR and the European Space Agency (ESA) to examine artificial gravity as a countermeasure to mitigate the effects of 60 days of bed rest. NASA is also considering collaborations with the Russian Institute for Biomedical Problems (IBMP) in studies that will utilize their Ground-based Experimental Facility (NEK). The NEK is comprised of 4 interconnected modules and a Martian surface simulator. This isolation analog can support 3 -10 crew members for long duration

  8. Analog computing for a new nuclear reactor dynamic model based on a time-dependent second order form of the neutron transport equation

    International Nuclear Information System (INIS)

    This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution

  9. Analog computing for a new nuclear reactor dynamic model based on a time-dependent second order form of the neutron transport equation

    Energy Technology Data Exchange (ETDEWEB)

    Pirouzmand, Ahmad; Hadad, Kamal [Shiraz University, Shiraz (Iran, Islamic Republic of); Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of)

    2011-06-15

    This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution

  10. Mineral formation on metallic copper in a `Future repository site environment`: Textural considerations based on natural analogs

    Energy Technology Data Exchange (ETDEWEB)

    Amcoff, Oe. [Uppsala Univ. (Sweden). Inst. of Earth Sciences

    1998-01-01

    Copper mineral formation in the Swedish `repository site environment` is discussed. Special attention is given to ore mineral textures (=the spatial relation among minerals), with examples given from nature. It is concluded: By analogy with observations from natural occurrences, an initial coating of Cu-oxide on the canister surface (because of entrapped air during construction) will probably not hinder a later sulphidation process. Early formation of Cu-sulphides on the canister surface may be accompanied by formation of CuFe-sulphides. The latter phase(s) may form through replacement of the Cu-sulphides or, alternatively, by means of reaction between dissolved copper and fine-grained iron sulphide (pyrite) in the surrounding bentonite. Should for some reason the bentonite barrier fail and the conditions become strongly oxidizing, we can expect crustifications and rhythmic growths of Cu(II)-phases, like malachite (Cu{sub 2}(OH){sub 2}CO{sub 3}). A presence of Fe{sup 2} in the clay minerals making up the bentonite might prove to have an adverse effect on the canister stability, since, in this case, the bentonite might be expected to act as a sink for dissolved copper. The mode of mineral growth along the copper - bentonite interface remains an open question.

  11. Modeling of ultrashort pulsed laser irradiation in the cornea based on parabolic and hyperbolic heat equations using electrical analogy

    Science.gov (United States)

    Gheitaghy, A. M.; Takabi, B.; Alizadeh, M.

    2014-03-01

    Hyperbolic and parabolic heat equations are formulated to study a nonperfused homogeneous transparent cornea irradiated by high power and ultrashort pulsed laser in the Laser Thermo Keratoplasty (LTK) surgery. Energy absorption inside the cornea is modeled using the Beer-Lambert law that is incorporated as an exponentially decaying heat source. The hyperbolic and parabolic bioheat models of the tissue were solved by exploiting the mathematical analogy between thermal and electrical systems, by using robust circuit simulation program called Hspice to get the solutions of simultaneous RLC and RC transmission line networks. This method can be used to rapidly calculate the temperature in laser-irradiated tissue at time and space domain. It is found that internal energy gained from the irradiated field results in a rapid rise of temperature in the cornea surface during the early heating period, while the hyperbolic wave model predicts a higher temperature rise than the classical heat diffusion model. In addition, this paper investigates and examines the effect of some critical parameters such as relaxation time, convection coefficient, radiation, tear evaporation and variable thermal conductivity of cornea. Accordingly, it is found that a better accordance between hyperbolic and parabolic models will be achieved by time.

  12. Structure-Activity Relationship-based Optimization of Small Temporin-SHf Analogs with Potent Antibacterial Activity.

    Science.gov (United States)

    André, Sonia; Washington, Shannon K; Darby, Emily; Vega, Marvin M; Filip, Ari D; Ash, Nathaniel S; Muzikar, Katy A; Piesse, Christophe; Foulon, Thierry; O'Leary, Daniel J; Ladram, Ali

    2015-10-16

    Short antimicrobial peptides represent attractive compounds for the development of new antibiotic agents. Previously, we identified an ultrashort hydrophobic and phenylalanine-rich peptide, called temporin-SHf, representing the smallest natural amphibian antimicrobial peptide known to date. Here, we report on the first structure-activity relationship study of this peptide. A series of temporin-SHf derivatives containing insertion of a basic arginine residue as well as residues containing neutral hydrophilic (serine and α-hydroxymethylserine) and hydrophobic (α-methyl phenylalanine and p-(t)butyl phenylalanine) groups were designed to improve the antimicrobial activity, and their α-helical structure was investigated by circular dichroism and nuclear magnetic resonance spectroscopy. Three compounds were found to display higher antimicrobial activity with the ability to disrupt (permeabilization/depolarization) the bacterial membrane while retaining the nontoxic character of the parent peptide toward rat erythrocytes and human cells (THP-1 derived macrophages and HEK-293). Antimicrobial assays were carried out to explore the influence of serum and physiological salt concentration on peptide activity. Analogs containing d-amino acid residues were also tested. Our study revealed that [p-(t)BuF(2), R(5)]SHf is an attractive ultrashort candidate that is highly potent (bactericidal) against Gram-positive bacteria (including multidrug resistant S. aureus) and against a wider range of clinically interesting Gram-negative bacteria than temporin-SHf, and also active at physiological salt concentrations and in 30% serum. PMID:26181487

  13. Mineral formation on metallic copper in a 'Future repository site environment': Textural considerations based on natural analogs

    International Nuclear Information System (INIS)

    Copper mineral formation in the Swedish 'repository site environment' is discussed. Special attention is given to ore mineral textures (=the spatial relation among minerals), with examples given from nature. It is concluded: By analogy with observations from natural occurrences, an initial coating of Cu-oxide on the canister surface (because of entrapped air during construction) will probably not hinder a later sulphidation process. Early formation of Cu-sulphides on the canister surface may be accompanied by formation of CuFe-sulphides. The latter phase(s) may form through replacement of the Cu-sulphides or, alternatively, by means of reaction between dissolved copper and fine-grained iron sulphide (pyrite) in the surrounding bentonite. Should for some reason the bentonite barrier fail and the conditions become strongly oxidizing, we can expect crustifications and rhythmic growths of Cu(II)-phases, like malachite (Cu2(OH)2CO3). A presence of Fe2 in the clay minerals making up the bentonite might prove to have an adverse effect on the canister stability, since, in this case, the bentonite might be expected to act as a sink for dissolved copper. The mode of mineral growth along the copper - bentonite interface remains an open question

  14. Regioselective enzymatic undecylenoylation of 8-chloroadenosine and its analogs with biomass-based 2-methyltetrahydrofuran as solvent.

    Science.gov (United States)

    Gao, Wen-Li; Liu, Huan; Li, Ning; Zong, Min-Hua

    2012-08-01

    2-Methyltetrahydrofuran (MeTHF), a biomass-derived compound, is a promising medium for biocatalysis and organometallic reactions. The regioselective acylation of 8-chloroadenosine (8-Cl-Ado) and its analogs was carried out in MeTHF with immobilized Penicillium expansum lipase. The lipase displayed more than twofold higher catalytic activity and much better thermostability in MeTHF than in other organic solvents and co-solvent systems. The optimum reaction medium, enzyme dosage, molar ratio of viny ester to nucleoside and reaction temperature for the enzymatic acylation of 8-Cl-Ado were MeTHF, 25 U/mL, 7.5 and 35 °C, respectively, under which the desirable 5'-O-undecylenoyl-8-Cl-Ado was obtained with a yield of 95% and a regioselectivity of >99% in 3 h. In addition, the lipase catalyzed regioselective undecylenoylation of other purine nucleosides, producing 5'-undecylenic acid esters with moderate to high yields (63-94%) and excellent 5'-regioselectivities (94->99%). Use of biomass-derived solvents might open up novel opportunities for sustainable and greener biocatalytic processes. PMID:22705510

  15. Insulin analogs and cancer

    Directory of Open Access Journals (Sweden)

    Laura eSciacca

    2012-02-01

    Full Text Available Today, insulin analogs are used in millions of diabetic patients. Insulin analogs have been developed to achieve more physiological insulin replacement in terms of time course of the effect. Modifications in the amino acid sequence of the insulin molecule change the pharmacokinetics and pharmacodynamics of the analogs in respect to human insulin. However, these changes can also modify the molecular and biological effects of the analogs. The rapid-acting insulin analogs, lispro, aspart and glulisine, have a rapid onset and shorter duration of action. The long-acting insulin analogs glargine and detemir have a protracted duration of action and a relatively smooth serum concentration profile. Insulin and its analogs may function as growth factors and therefore have a theoretical potential to promote tumor proliferation. A major question is whether analogs have an increased mitogenic activity in respect to insulin. These ligands can promote cell proliferation through many mechanisms like the prolonged stimulation of the insulin receptor, stimulation of the IGF-1 receptor (IGF-1R, prevalent activation of the ERK rather than the AKT intracellular post-receptor pathways. Studies on in vitro models indicate that short-acting analogs elicit molecular and biological effects that are similar to those of insulin. In contrast, long-acting analogs behave differently. Although not all data are homogeneous, both glargine and detemir have been found to have a decreased binding to IR but an increased binding to IGF-1R, a prevalent activation of the ERK pathway, and an increased mitogenic effect in respect to insulin. Recent retrospective epidemiological clinical studies have suggested that treatment with long-acting analogs (specifically glargine may increase the relative risk for cancer. Results are controversial and methodologically weak. Therefore prospective clinical studies are needed to evaluate the possible tumor growth-promoting effects of these insulin

  16. The Analogical Mind

    OpenAIRE

    Holyoak, Keith J.; Thagard, P.

    1997-01-01

    We examine the use of analogy in human thinking from the perspective of a multiconstraint theory, which postulates three basic types of constraints: similarity, structure and purpose. The operation of these constraints is apparent in both laboratory experiments on analogy and in naturalistic settings, including politics, psychotherapy, and scientific research. We sketch how the multiconstraint theory can be implemented in detailed computational simulations of the analogical human mind.

  17. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  18. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2011-01-01

    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling is...

  19. Priming analogical reasoning with false memories.

    Science.gov (United States)

    Howe, Mark L; Garner, Sarah R; Threadgold, Emma; Ball, Linden J

    2015-08-01

    Like true memories, false memories are capable of priming answers to insight-based problems. Recent research has attempted to extend this paradigm to more advanced problem-solving tasks, including those involving verbal analogical reasoning. However, these experiments are constrained inasmuch as problem solutions could be generated via spreading activation mechanisms (much like false memories themselves) rather than using complex reasoning processes. In three experiments we examined false memory priming of complex analogical reasoning tasks in the absence of simple semantic associations. In Experiment 1, we demonstrated the robustness of false memory priming in analogical reasoning when backward associative strength among the problem terms was eliminated. In Experiments 2a and 2b, we extended these findings by demonstrating priming on newly created homonym analogies that can only be solved by inhibiting semantic associations within the analogy. Overall, the findings of the present experiments provide evidence that the efficacy of false memory priming extends to complex analogical reasoning problems. PMID:25784574

  20. COMPUTER OF TESTING ON DISCIPLINE "BASES ELECTRICAL ENGINEERS AND ELECTRONICS"

    OpenAIRE

    Zarzhetskaja, N.; Noskov, M.

    2010-01-01

    In the given work application of program Electronics Workbench for teaching a rate is described: « Bases electrical engineers and electronics ». It is offered to use the program for carrying out of laboratory works and testing's of quality of knowledge of students. This approach raises quality of mastering of material students. It is the tool for independent check of results. Use of the program fixes the basic skills of calculations of electric circuits. In work the block from six laboratory ...

  1. Chemical Functionalization Effects on Cubane-Based Chain Electronic Transport

    OpenAIRE

    Konstantin P. Katin; Mikhail M. Maslov

    2015-01-01

    We report electronic structure calculations in chemically functionalized linear cubane-based chains. The effects of covalent chemical attachments on chain transport properties are examined with nonorthogonal tight-binding model (NTBM) considering Landauer-Büttiker formalism. The covalent bonding of even a single-type functional group is shown to considerably alter the conductance of the chain. For similar radical doping density, electronic characteristics are found to range from insulator to ...

  2. Design of wireless electronic stethoscope based on zigbee

    OpenAIRE

    Kadam Patil D.D; Shastri R.K

    2012-01-01

    Heart sound stethoscope is primary stage to access diseases. In this paper design of an electronic stethoscope with the functions of wireless transmission is discussed. This electronic stethoscope based on embedded processor. The data can be transmitted through wireless transmission using Zigbee module. A microphone is used to pick up the sound of the heart beat. Acoustic stethoscope can be changed into a digital stethoscope by inserting an electric capacity microphone into its head. The sig...

  3. Secure electronic commerce communication system based on CA

    Science.gov (United States)

    Chen, Deyun; Zhang, Junfeng; Pei, Shujun

    2001-07-01

    In this paper, we introduce the situation of electronic commercial security, then we analyze the working process and security for SSL protocol. At last, we propose a secure electronic commerce communication system based on CA. The system provide secure services such as encryption, integer, peer authentication and non-repudiation for application layer communication software of browser clients' and web server. The system can implement automatic allocation and united management of key through setting up the CA in the network.

  4. Graphene Electronic Device Based Biosensors and Chemical Sensors

    OpenAIRE

    Jiang, Shan

    2014-01-01

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first...

  5. Estimation of channel mismatches in time-interleaved analog-to-digital converters based on fractional delay and sine curve fitting.

    Science.gov (United States)

    Guo, Lianping; Tian, Shulin; Jiang, Jun

    2015-03-01

    This paper proposes an algorithm to estimate the channel mismatches in time-interleaved analog-to-digital converter (TIADC) based on fractional delay (FD) and sine curve fitting. Choose one channel as the reference channel and apply FD to the output samples of reference channel to obtain the ideal samples of non-reference channels with no mismatches. Based on least square method, the sine curves are adopted to fit the ideal and the actual samples of non-reference channels, and then the mismatch parameters can be estimated by comparing the ideal sine curves and the actual ones. The principle of this algorithm is simple and easily understood. Moreover, its implementation needs no extra circuits, lowering the hardware cost. Simulation results show that the estimation accuracy of this algorithm can be controlled within 2%. Finally, the practicability of this algorithm is verified by the measurement results of channel mismatch errors of a two-channel TIADC prototype. PMID:25832264

  6. Cyclic pentapeptide analogs based on endomorphin-2 structure: cyclization studies using liquid chromatography combined with on-line mass spectrometry and tandem mass spectrometry.

    Science.gov (United States)

    Piekielna, Justyna; Kluczyk, Alicja; Perlikowska, Renata; Janecka, Anna

    2014-05-01

    The cyclization of linear analogs based on endomorphin-2 structure, Tyr/Dmt-d-Lys-Phe-Phe-Asp-NH2 and Tyr/Dmt-d-Cys-Phe-Phe-Cys-NH2 (where Dmt=2',6'-dimethyltyrosine), resulting in obtaining lactam or disulfide derivatives, was studied using liquid chromatography combined with on-line mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS). In case of cyclization via an amide bond, the formation of the cyclic monomers, cyclic but not linear dimers and even traces of cyclic trimers was observed. Disulfide bridge containing peptides was obtained by the solid-phase synthesis of the linear sequences, followed by either in-solution or on-resin cyclization. In case of the in-solution cyclization, the expected cyclic monomers were the only products. When oxidation of the cysteine residues was performed when the peptides were still on the resin, cyclic monomer and two cyclodimers, parallel and antiparallel, were found. Digestion of the isolated cyclodimers with α-chymotrypsin allowed for their unambiguous identification. The comparison of the cyclic monomer/dimer ratios for analogs with Tyr versus Dmt in position 1 revealed that the presence of the exocyclic Dmt favored formation of the cyclic monomer, most likely due to the increased steric bulk of this amino acid side-chain as compared with Tyr. PMID:24525024

  7. Several Forms of Fuzzy Analogical Reasoning

    OpenAIRE

    Bouchon-Meunier, B; Delechamp, J.; Marsala, C.; Rifqi, M.

    1997-01-01

    We present a general framework representing analogy, on the basis of a link between variables and measures of comparison between values of variables. This analogical scheme is proven to represent a common description of several forms of reasoning used in fuzzy control or in the management of knowledge-based systems, such as deductive reasoning, inductive reasoning or prototypical reasoning, gradual reasoning.

  8. Semiconductor-based, large-area, flexible, electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Amit (Knoxville, TN)

    2011-03-15

    Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  9. Hydraulic Capacitor Analogy

    Science.gov (United States)

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  10. Analog pulse processor

    Science.gov (United States)

    Wessendorf, Kurt O.; Kemper, Dale A.

    2003-06-03

    A very low power analog pulse processing system implemented as an ASIC useful for processing signals from radiation detectors, among other things. The system incorporates the functions of a charge sensitive amplifier, a shaping amplifier, a peak sample and hold circuit, and, optionally, an analog to digital converter and associated drivers.

  11. Synaptic dynamics in analog VLSI.

    Science.gov (United States)

    Bartolozzi, Chiara; Indiveri, Giacomo

    2007-10-01

    Synapses are crucial elements for computation and information transfer in both real and artificial neural systems. Recent experimental findings and theoretical models of pulse-based neural networks suggest that synaptic dynamics can play a crucial role for learning neural codes and encoding spatiotemporal spike patterns. Within the context of hardware implementations of pulse-based neural networks, several analog VLSI circuits modeling synaptic functionality have been proposed. We present an overview of previously proposed circuits and describe a novel analog VLSI synaptic circuit suitable for integration in large VLSI spike-based neural systems. The circuit proposed is based on a computational model that fits the real postsynaptic currents with exponentials. We present experimental data showing how the circuit exhibits realistic dynamics and show how it can be connected to additional modules for implementing a wide range of synaptic properties. PMID:17716003

  12. Investigation of Higher Brain Functions in Music Composition Using Models of the Cortex Based on Physical System Analogies.

    Science.gov (United States)

    Leng, Xiaodan

    The trion model was developed using the Mountcastle organizational principle for the column as the basic neuronal network in the cortex and the physical system analogy of Fisher's ANNNI spin model. An essential feature is that it is highly structured in time and in spatial connections. Simulations of a network of trions have shown that large numbers of quasi-stable, periodic spatial-temporal firing patterns can be excited. Characteristics of these patterns include the quality of being readily enhanced by only a small change in connection strengths, and that the patterns evolve in certain natural sequences from one to another. With only somewhat different parameters than used for studying memory and pattern recognition, much more flowing and intriguing patterns emerged from the simulations. The results were striking when these probabilistic evolutions were mapped onto pitches and instruments to produce music: For example different simple mappings of the same evolution give music having the "flavor" of a minuet, a waltz, folk music, or styles of specific periods. A theme can be learned so that evolutions have this theme and its variations reoccurring more often. That the trion model is a viable model for the coding of musical structure in human composition and perception is suggested. It is further proposed that model is relevant for examining creativity in the higher cognitive functions of mathematics and chess, which are similar to music. An even higher level of cortical organization was modeled by coupling together several trion networks. Further, one of the crucial features of higher brain function, especially in music composition or appreciation, is the role of emotion and mood as controlled by the many neuromodulators or neuropeptides. The MILA model whose underlying basis is zero-level representation of Kac-Moody algebra is used to modulate periodically the firing threshold of each network. Our preliminary results show that the introduction of "neuromodulation

  13. Satellite-Based Thermophysical Analysis of Volcaniclastic Deposits: A Terrestrial Analog for Mantled Lava Flows on Mars

    Directory of Open Access Journals (Sweden)

    Mark A. Price

    2016-02-01

    Full Text Available Orbital thermal infrared (TIR remote sensing is an important tool for characterizing geologic surfaces on Earth and Mars. However, deposition of material from volcanic or eolian activity results in bedrock surfaces becoming significantly mantled over time, hindering the accuracy of TIR compositional analysis. Moreover, interplay between particle size, albedo, composition and surface roughness add complexity to these interpretations. Apparent Thermal Inertia (ATI is the measure of the resistance to temperature change and has been used to determine parameters such as grain/block size, density/mantling, and the presence of subsurface soil moisture/ice. Our objective is to document the quantitative relationship between ATI derived from orbital visible/near infrared (VNIR and thermal infrared (TIR data and tephra fall mantling of the Mono Craters and Domes (MCD in California, which were chosen as an analog for partially mantled flows observed at Arsia Mons volcano on Mars. The ATI data were created from two images collected ~12 h apart by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER instrument. The results were validated with a quantitative framework developed using fieldwork that was conducted at 13 pre-chosen sites. These sites ranged in grain size from ash-sized to meter-scale blocks and were all rhyolitic in composition. Block size and mantling were directly correlated with ATI. Areas with ATI under 2.3 × 10−2 were well-mantled with average grain size below 4 cm; whereas values greater than 3.0 × 10−2 corresponded to mantle-free surfaces. Correlation was less accurate where checkerboard-style mixing between mantled and non-mantled surfaces occurred below the pixel scale as well as in locations where strong shadowing occurred. However, the results validate that the approach is viable for a large majority of mantled surfaces on Earth and Mars. This is relevant for determining the volcanic history of Mars, for

  14. Electron irradiation of carbon dioxide-carbon disulphide ice analog and its implication on the identification of carbon disulphide on Moon

    Indian Academy of Sciences (India)

    B Sivaraman

    2016-01-01

    Carbon dioxide (CO2) and carbon disulphide (CS2) molecular ice mixture was prepared under low temperature (85 K) astrochemical conditions. The icy mixture irradiated with keV electrons simulates the irradiation environment experienced by icy satellites and Interstellar Icy Mantles (IIM). Upon electron irradiation the chemical composition was found to have altered and the new products from irradiation were found to be carbonyl sulphide (OCS), sulphur dioxide (SO2), ozone (O3), carbon trioxide (CO3), sulphur trioxide (SO3), carbon subsulphide (C3S2) and carbon monoxide (CO). Results obtained confirm the presence of CS2 molecules in lunar south-pole probed by the Moon Impact Probe (MIP).

  15. Ab initio electronic and optical spectra of free-base porphyrins: The role of electronic correlation.

    Science.gov (United States)

    Palummo, Maurizia; Hogan, Conor; Sottile, Francesco; Bagalá, Paolo; Rubio, Angel

    2009-08-28

    We present a theoretical investigation of electronic and optical properties of free-base porphyrins based on density functional theory and many-body perturbation theory. The electronic levels of free-base porphine (H(2)P) and its phenyl derivative, free-base tetraphenylporphyrin (H(2)TPP) are calculated using the ab initio GW approximation for the self-energy. The approach is found to yield results that compare favorably with the available photoemission spectra. The excitonic nature of the optical peaks is revealed by solving the Bethe-Salpeter equation, which provides an accurate description of the experimental absorption spectra. The lowest triplet transition energies are in good agreement with the measured values. PMID:19725603

  16. Computational approaches to analogical reasoning current trends

    CERN Document Server

    Richard, Gilles

    2014-01-01

    Analogical reasoning is known as a powerful mode for drawing plausible conclusions and solving problems. It has been the topic of a huge number of works by philosophers, anthropologists, linguists, psychologists, and computer scientists. As such, it has been early studied in artificial intelligence, with a particular renewal of interest in the last decade. The present volume provides a structured view of current research trends on computational approaches to analogical reasoning. It starts with an overview of the field, with an extensive bibliography. The 14 collected contributions cover a large scope of issues. First, the use of analogical proportions and analogies is explained and discussed in various natural language processing problems, as well as in automated deduction. Then, different formal frameworks for handling analogies are presented, dealing with case-based reasoning, heuristic-driven theory projection, commonsense reasoning about incomplete rule bases, logical proportions induced by similarity an...

  17. Full characterization of self-phase-modulation based low-noise, cavity-less pulse source for photonic-assisted analog-to-digital conversion.

    Science.gov (United States)

    Liu, Lan; Tong, Zhi; Wiberg, Andreas O J; Myslivets, Evgeny; Alic, Nikola; Radic, Stojan

    2012-12-10

    A high quality cavity-less pulse source, realized as a combination of linear pulse compression and self-phase-modulation (SPM) based regeneration is demonstrated and strictly characterized for the first time. The regenerated pulses, with 3.6 GHz repetition rate, are optimized through rigorous relative intensity-noise (RIN) measurement. Temporal intensity and chirp characterizations demonstrate that the pulses exhibit characteristic of low RIN, and are chirp- and pedestal-free. The cavity-less pulse source is further tested in a photonic-assisted analog-to-digital (ADC) configuration as the sampling source. A record result of more than 8 effective quantization bits at 202 MHz is demonstrated. PMID:23262840

  18. A High-Resolution Transmission-Type (TT) Phaser Based on Reflection-Type (RT) Units for Radio Analog Signal Processing (R-ASP)

    CERN Document Server

    Zou, Lianfeng

    2014-01-01

    A high Radio Analog Signal Processing (R-ASP) resolution transmission-type (TT) phaser based on reflection-type (RT) phaser units is introduced, theoretically studied and experimentally demonstrated. It is first shown that RT phasers inherently exhibit higher R-ASP resolution than their TT counterparts because their group delay swing is proportional to the reflection coefficient associated with a resonator coupling mechanism (admittance inverter), easy to maximize towards unity, rather than to a coupled-line coupling coefficient, typically restricted to values will inferior to unity, as in the RT case. Moreover, a detailed sensitivity analysis reveals that the proposed phaser is simultaneously features high R-ASP resolution and low sensitivity to fabrication tolerance, which makes it an ideal solution for R-ASP. The proposed phaser exhibits a 5 ns group delay swing over a fractional bandwidth of about 50% around 4 GHz.

  19. Automated Generation of Cross-Domain Analogies via Evolutionary Computation

    CERN Document Server

    Baydin, Atilim Gunes; Ontanon, Santiago

    2012-01-01

    Analogy plays an important role in creativity, and is extensively used in science as well as art. In this paper we introduce a technique for the automated generation of cross-domain analogies based on a novel evolutionary algorithm (EA). Unlike existing work in computational analogy-making restricted to creating analogies between two given cases, our approach, for a given case, is capable of creating an analogy along with the novel analogous case itself. Our algorithm is based on the concept of "memes", which are units of culture, or knowledge, undergoing variation and selection under a fitness measure, and represents evolving pieces of knowledge as semantic networks. Using a fitness function based on Gentner's structure mapping theory of analogies, we demonstrate the feasibility of spontaneously generating semantic networks that are analogous to a given base network.

  20. Meat analog: a review.

    Science.gov (United States)

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers. PMID:24915320

  1. Electronic and chemical properties of graphene-based structures:

    DEFF Research Database (Denmark)

    Vanin, Marco

    In the present thesis several aspects of graphene-based structures have been investigated using density functional theory calculations to solve the electronic structure problem. A review of the implementation of a localized basis-set within the projector augmented wave method - the way of describ...... are attractive candidates although issues regarding the poisoning of the active site remain to be addressed....

  2. Fullerene-based Anchoring Groups for Molecular Electronics

    DEFF Research Database (Denmark)

    Martin, Christian A.; Ding, Dapeng; Sørensen, Jakob Kryger;

    2008-01-01

    We present results on a new fullerene-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vacuum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can...

  3. Wafer-level chip-scale packaging analog and power semiconductor applications

    CERN Document Server

    Qu, Shichun

    2015-01-01

    This book presents a state-of-art and in-depth overview in analog and power WLCSP design, material characterization, reliability, and modeling. Recent advances in analog and power electronic WLCSP packaging are presented based on the development of analog technology and power device integration. The book covers in detail how advances in semiconductor content, analog and power advanced WLCSP design, assembly, materials, and reliability have co-enabled significant advances in fan-in and fan-out with redistributed layer (RDL) of analog and power device capability during recent years. Along with new analog and power WLCSP development, the role of modeling is a key to assure successful package design. An overview of the analog and power WLCSP modeling and typical thermal, electrical, and stress modeling methodologies is also provided. This book also: ·         Covers the development of wafer-level power discrete packaging with regular wafer-level design concepts and directly bumping technology ·    �...

  4. Synthesis of a fluorescence resonance energy transfer-based probe containing a tricyclic nucleoside analog for single nucleotide polymorphism typing.

    Science.gov (United States)

    Hayai, Aya; Maeda, Yusuke; Ueno, Yoshihito

    2016-08-01

    Here, we report the synthesis of a fluorescence resonance energy transfer (FRET)-based probe for single nucleotide polymorphism (SNP) typing. The probe contains a fluorescent tricyclic base, 8-amino-3-(2,3-dihydroxypropyl)imidazo[4',5':5,6]pyrido[2,3-d]pyrimidine, as a donor molecule and 7-diethylaminocoumarin-3-carboxylic acid as an acceptor molecule. FRET was observed between the donor and acceptor molecules on the probe. The identity of the target bases on DNA and RNA strands could be determined using the probe. PMID:27329795

  5. Study of the electron transfer in analog compounds of the Prussia blue; Estudio de transferencia electronica en compuestos analogos del azul de Prusia

    Energy Technology Data Exchange (ETDEWEB)

    Romero V, S.; Damaso C, L.F. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Reguera R, E.; Yee M, H.T. [CICATA-IPN, 11500 Mexico D.F. (Mexico)

    2006-07-01

    As answer to the necessity of the search of new nano structured materials, the present work was carried out that it studies the electron transfer in compound similar of the Prussia blue (CAAP), which are representative molecular materials, because its chromophore, magnetic, and electric properties, depend mainly on the processes that are made in their levels or orbital energy. It is known that these made up with octahedra symmetry that its are presented in form of powders, suffer processes of electron transfer when its are exposed to external stimulation by means of light (embracing the regions from the ultraviolet one until the infrared in the electromagnetic spectrum), because they are made up of mixed valency. To know that types of electronic transfers are those that are made in the study materials, 4 series of CAAP its were synthesized by the method of mixtures of aqueous solutions: M[Fe{sup +3}CN){sub 6}]{sub 2}nH{sub 2}O, M[Cr{sup +3}(CN){sub 6}]{sub 2}nH{sub 2}O, M[Mn{sup +3}(CN){sub 6}]{sub 3}nH{sub 2}O y M[Co{sup +3}(CN){sub 6}]{sub 3}nH{sub 2}O, and later on studied by means of the electron spectroscopy technique with a UV-SENSE spectrophotometer (Perkin-Elmer) in or n range of work of 250 to 1100 nm. Because to discuss the electronic structures of any compound, it is required the calculation of the energy levels, they took like reference the data tabulated by John Alexander and Harry Gray calculated by the modified theoretical approach of Wolfsberg-Helmhoz. When comparing the obtained spectra with the theoretical data, it was concludes that in the CAAP, its are carried out electronic transfers among orbital molecular metallic of the type d {yields} d, and load transfer (TC) among orbital molecular of the ligand and metal. When being carried out a load transfer in the CAAP that initially are made up of under-spin these its are photoinduced to an excited state of high spin. In consequence it is possible to vary the interactions among the metals of

  6. Electron beam charge measurement on PHIL photo-injector using a microcontroller based system

    International Nuclear Information System (INIS)

    PHIL [1] is an electron beam accelerator at LAL. It produces low energy (E < 5 MeV) and high current (maximum 2nC/bunch, 10 ps duration) electron bunch at a repetition frequency of 5Hz. The beam charge measurements are performed by two Faraday Cups (FC) at both ends of the beam line and also with two Integrating Current Transformer (ICT), installed immediately after the RF gun and at the end of the straight beam line (see figure 1). Extracted signals from the ICT and FC, are processed by electronic circuits, displayed on an oscilloscope, and used to calculate the beam charge manually using the oscilloscope features. This operation is not accurate, does't permit to follow and save the temporal evolution of the charge and cannot be integrated in the control command system. To overcome this problem, a new approach was adopted, based on two systems: - An electronic back-end to integrate the signal from coming the charge measurement systems (20ns large pulse), and outputs a large duration signal (around 400μs) whose amplitude is proportional to the beam charge. - A microcontroller is used to acquire the integrated signal with a repetition rate of 5Hz, make the analog-digital conversion, and calculate the mean beam charge. The output signal can be sent to the control command system for displaying and to automate other process, especially the measurements of the beam charge versus RF/Laser phase. This system offers good accuracy, with a resolution of around 1pC, and can be easily integrated in the control command system

  7. Design of CPLD-DAC based probe bias generator and current measurement electronics

    International Nuclear Information System (INIS)

    In Institute for Plasma Research Multi-Cusp Plasma experiment is being pursued. In Multi-Cusp Plasma experiment contact-ionized cesium ions will be confined by a multi-cusp magnetic field configuration. The cesium ions will be produced by impinging collimated neutral Cesium atoms on a hot tungsten plate. The temperature of the tungsten plate will also be made high enough such that it will contribute electrons also to charge neutralize the plasma. Since this plasma will not be emitting any visible or UV radiations, electric probes are the only diagnostics planned for the time being. The probe needs to be biased with ramp or triangular signal waveforms of fixed amplitude of +/- 15 V and frequency of 50 Hz for different plasma experiments. A combination of Complex programmable Logic Device (CPLD) and Digital to Analog Convertor (DAC) based waveform generator is conceptually designed. The programmable devices play a very important role where flexibility of programming the amplitude as well as the frequency of the bias waveform is required. The accuracy of the bias waveform can be set to as low as in the micro volt ranges. At present a 16 bit DAC will be interfaced with the CPLD. The requirement also involves development of signal conditioning electronics for the probe current measurement. Plasma current measurement is very tricky as it needs to extract the low amplitude AC signal from DC bias voltage. Accurate difference amplifier is designed to achieve maximum AC CMRR to extract the real signal. The signal conditioning electronics is a combination of I-V convertor, a precision difference amplifier, optical isolator and driver. SMD components are selected to make the circuit compact and rugged. This paper describes the hardware and software design aspects of electronics. (author)

  8. The design and simulation of a titanium oxide memristor-based programmable analog filter in a simulation program with integrated circuit emphasis

    International Nuclear Information System (INIS)

    In many communication and signal routing applications, it is desirable to have a programmable analog filter. According to this practical demand, we consider the titanium oxide memristor, which is a kind of nano-scale electron device with low power dissipation and nonvolatile memory. Such characteristics could be suitable for designing the desired filter. However, both the non-analytical relation between the memristance and the charges that pass through it, and the changeable V—I characteristics in physical tests make it difficult to accurately set the memristance to the target value. In this paper, the conductive mechanism of the memristor is analyzed, a method of continuously programming the memristance is proposed and simulated in a simulation program with integrated circuit emphasis, and its feasibility and compatibility, both in simulations and physical realizations, are demonstrated. This method is then utilized in a first-order active filter as an example to show its applications in programmable filters. This work also provides a practical tool for utilizing memristors as resistance programmable devices. (interdisciplinary physics and related areas of science and technology)

  9. The design and simulation of a titanium oxide memristor-based programmable analog filter in a simulation program with integrated circuit emphasis

    Institute of Scientific and Technical Information of China (English)

    Tian Xiao-Bo; Xu Hui

    2013-01-01

    In many communication and signal routing applications,it is desirable to have a programmable analog filter.According to this practical demand,we consider the titanium oxide memristor,which is a kind of nano-scale electron device with low power dissipation and nonvolatile memory.Such characteristics could be suitable for designing the desired filter.However,both the non-analytical relation between the memristance and the charges that pass through it,and the changeable V-I characteristics in physical tests make it difficult to accurately set the memristance to the target value.In this paper,the conductive mechanism of the memristor is analyzed,a method of continuously programming the memristance is proposed and simulated in a simulation program with integrated circuit emphasis,and its feasibility and compatibility,both in simulations and physical realizations,are demonstrated.This method is then utilized in a first-order active filter as an example to show its applications in programmable filters.This work also provides a practical tool for utilizing memristors as resistance programmable devices.

  10. Design of the Q Meter Based on AD633 Analog Phase Detection%基于AD633模拟鉴相的Q表设计

    Institute of Scientific and Technical Information of China (English)

    葛维亮; 奚大顺; 庹先国; 王洪辉; 李怀良; 张赓; 宋茜茜

    2011-01-01

    In order to solve the problem that the multimeters are unable to measure the parameters of Q, D, etc., the Q meter based on AD633 analog phase detection has been designed. In the instrument, the sine energizing signal and reference signal are generated by the DDS chip AD9851, and phase detection of the signal is implemented by using highly integrated analog multiplier AD633. The single end output signal of phase detection is then converted into differential signal by the differential converter AD8138; and the differential signal is converted into digital and processed by the self-contained ADC of C8051F060. This instrument offers the functions of automatic range changeover, LCD real-time display; and features of compact, low cost as well an meets the measurement demands in engineering projects, teaching and research areas.%为解决万用表无法测量Q、D等参数的问题,设计了基于A1D633模拟鉴相的Q表.该测量仪采用DDS芯片AD9851产生正弦激励信号和基准信号,利用高集成度模拟乘法器AD633对信号进行模拟鉴相,并采用差分转换器AD8138对鉴相输出信号进行单端转差分变换,由C8051F060内部自带的ADC对差分信号进行模数转换和数据处理.Q表具有多量程自动切换和LCD实时显示等功能,且体积小、成本低,能满足工程、教学科研测量的需要.

  11. Classical analogy of Fano resonances

    International Nuclear Information System (INIS)

    We present an analogy of Fano resonances in quantum interference to classical resonances in the harmonic oscillator system. It has a manifestation as a coupled behaviour of two effective oscillators associated with propagating and evanescent waves. We illustrate this point by considering a classical system of two coupled oscillators and interfering electron waves in a quasi-one-dimensional narrow constriction with a quantum dot. Our approach provides a novel insight into Fano resonance physics and provides a helpful view in teaching Fano resonances

  12. A laser printing based approach for printed electronics

    Science.gov (United States)

    Zhang, T.; Hu, M.; Liu, Y.; Guo, Q.; Wang, X.; Zhang, W.; Lau, W.; Yang, J.

    2016-03-01

    Here we report a study of printing of electronics using an office use laser printer. The proposed method eliminates those critical disadvantages of solvent-based printing techniques by taking the advantages of electroless deposition and laser printing. The synthesized toner acts as a catalyst for the electroless copper deposition as well as an adhesion-promoting buffer layer between the substrate and deposited copper. The easy metallization of printed patterns and strong metal-substrate adhesion make it an especially effective method for massive production of flexible printed circuits. The proposed process is a high throughput, low cost, efficient, and environmentally benign method for flexible electronics manufacturing.

  13. Electronic properties of graphene-based bilayer systems

    Science.gov (United States)

    Rozhkov, A. V.; Sboychakov, A. O.; Rakhmanov, A. L.; Nori, Franco

    2016-08-01

    This article reviews the theoretical and experimental work related to the electronic properties of bilayer graphene systems. Three types of bilayer stackings are discussed: the AA, AB, and twisted bilayer graphene. This review covers single-electron properties, effects of static electric and magnetic fields, bilayer-based mesoscopic systems, spin-orbit coupling, dc transport and optical response, as well as spontaneous symmetry violation and other interaction effects. The selection of the material aims to introduce the reader to the most commonly studied topics of theoretical and experimental research in bilayer graphene.

  14. Model Checking Electronic Commerce Security Protocols Based on CTL

    Institute of Scientific and Technical Information of China (English)

    XIAO De-qin; ZHANG Huan-guo

    2005-01-01

    We present a model based on Computational Temporal Logic (CTL) methods for verifying security requirements of electronic commerce protocols. The model describes formally the authentication, confidentiality integrity,non-repudiation, denial of service and access control of the electronic commerce protocols. We illustrate as case study a variant of the Lu-Smolka protocol proposed by Lu-Smolka.Moreover, we have discovered two attacks that allow a dishonest user to purchase a good debiting the amount to another user. And also, we compared our work with relative research works and found that the formal way of this paper is more general to specify security protocols for E-Commerce.

  15. Multifunctional bulk plasma source based on discharge with electron injection.

    Science.gov (United States)

    Klimov, A S; Medovnik, A V; Tyunkov, A V; Savkin, K P; Shandrikov, M V; Vizir, A V

    2013-01-01

    A bulk plasma source, based on a high-current dc glow discharge with electron injection, is described. Electron injection and some special design features of the plasma arc emitter provide a plasma source with very long periods between maintenance down-times and a long overall lifetime. The source uses a sectioned sputter-electrode array with six individual sputter targets, each of which can be independently biased. This discharge assembly configuration provides multifunctional operation, including plasma generation from different gases (argon, nitrogen, oxygen, acetylene) and deposition of composite metal nitride and oxide coatings. PMID:23387642

  16. Electronic implementation of associative memory based on neural network models

    Science.gov (United States)

    Moopenn, A.; Lambe, John; Thakoor, A. P.

    1987-01-01

    An electronic embodiment of a neural network based associative memory in the form of a binary connection matrix is described. The nature of false memory errors, their effect on the information storage capacity of binary connection matrix memories, and a novel technique to eliminate such errors with the help of asymmetrical extra connections are discussed. The stability of the matrix memory system incorporating a unique local inhibition scheme is analyzed in terms of local minimization of an energy function. The memory's stability, dynamic behavior, and recall capability are investigated using a 32-'neuron' electronic neural network memory with a 1024-programmable binary connection matrix.

  17. Alumina Based 500 C Electronic Packaging Systems and Future Development

    Science.gov (United States)

    Chen, Liang-Yu

    2012-01-01

    NASA space and aeronautical missions for probing the inner solar planets as well as for in situ monitoring and control of next-generation aeronautical engines require high-temperature environment operable sensors and electronics. A 96% aluminum oxide and Au thick-film metallization based packaging system including chip-level packages, printed circuit board, and edge-connector is in development for high temperature SiC electronics. An electronic packaging system based on this material system was successfully tested and demonstrated with SiC electronics at 500 C for over 10,000 hours in laboratory conditions previously. In addition to the tests in laboratory environments, this packaging system has more recently been tested with a SiC junction field effect transistor (JFET) on low earth orbit through the NASA Materials on the International Space Station Experiment 7 (MISSE7). A SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE7 suite to International Space Station via a Shuttle mission and tested on the orbit for eighteen months. A summary of results of tests in both laboratory and space environments will be presented. The future development of alumina based high temperature packaging using co-fired material systems for improved performance at high temperature and more feasible mass production will also be discussed.

  18. TV Analog Station Transmitters

    Data.gov (United States)

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Analog Television Stations (see Rule Part47 CFR...

  19. A count rate based contamination control standard for electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    May, R.T.; Schwahn, S.O.

    1996-12-31

    Accelerators of sufficient energy and particle fluence can produce radioactivity as an unwanted byproduct. The radioactivity is typically imbedded in structural materials but may also be removable from surfaces. Many of these radionuclides decay by positron emission or electron capture; they often have long half lives and produce photons of low energy and yield making detection by standard devices difficult. The contamination control limit used throughout the US nuclear industry and the Department of Energy is 1,000 disintegrations per minute. This limit is based on the detection threshold of pancake type Geiger-Mueller probes for radionuclides of relatively high radiotoxicity, such as cobalt-60. Several radionuclides of concern at a high energy electron accelerator are compared in terms of radiotoxicity with radionuclides commonly found in the nuclear industry. Based on this comparison, a count-rate based contamination control limit and associated measurement strategy is proposed which provides adequate detection of contamination at accelerators without an increase in risk.

  20. Portable audio electronics for impedance-based measurements in microfluidics

    International Nuclear Information System (INIS)

    We demonstrate the use of audio electronics-based signals to perform on-chip electrochemical measurements. Cell phones and portable music players are examples of consumer electronics that are easily operated and are ubiquitous worldwide. Audio output (play) and input (record) signals are voltage based and contain frequency and amplitude information. A cell phone, laptop soundcard and two compact audio players are compared with respect to frequency response; the laptop soundcard provides the most uniform frequency response, while the cell phone performance is found to be insufficient. The audio signals in the common portable music players and laptop soundcard operate in the range of 20 Hz to 20 kHz and are found to be applicable, as voltage input and output signals, to impedance-based electrochemical measurements in microfluidic systems. Validated impedance-based measurements of concentration (0.1–50 mM), flow rate (2–120 µL min−1) and particle detection (32 µm diameter) are demonstrated. The prevailing, lossless, wave audio file format is found to be suitable for data transmission to and from external sources, such as a centralized lab, and the cost of all hardware (in addition to audio devices) is ∼10 USD. The utility demonstrated here, in combination with the ubiquitous nature of portable audio electronics, presents new opportunities for impedance-based measurements in portable microfluidic systems. (technical note)

  1. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  2. Synthesis of Paclitaxel Analogs

    OpenAIRE

    Xu, Zhibing

    2010-01-01

    Paclitaxel is one of the most successful anti-cancer drugs, particularly in the treatment of breast cancer and ovarian cancer. For the investigation of the interaction between paclitaxel and MD-2 protein, and development of new antagonists for lipopolysaccharide, several C10 A-nor-paclitaxel analogs have been synthesized and their biological activities have been evaluated. In order to reduce the myelosuppression effect of the paclitaxel, several C3â ² and C4 paclitaxel analogs have been synth...

  3. Structure Based Docking and Molecular Dynamic Studies of Plasmodial Cysteine Proteases against a South African Natural Compound and its Analogs.

    Science.gov (United States)

    Musyoka, Thommas M; Kanzi, Aquillah M; Lobb, Kevin A; Tastan Bishop, Özlem

    2016-01-01

    Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species. Structure based virtual docking approach was used to screen a small non-peptidic library of natural compounds from South Africa against 11 proteins. A potential hit, 5α-Pregna-1,20-dien-3-one (5PGA), with inhibitory activity against plasmodial proteases and selectivity on human cathepsins was identified. A 3D similarity search on the ZINC database using 5PGA identified five potential hits based on their docking energies. The key interacting residues of proteins with compounds were identified via molecular dynamics and free binding energy calculations. Overall, this study provides a basis for further chemical design for more effective derivatives of these compounds. Interestingly, as these compounds have cholesterol-like nuclei, they and their derivatives might be well tolerated in humans. PMID:27030511

  4. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  5. Recent advances in molecular electronics based on carbon nanotubes.

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

    2010-01-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field. PMID:21137718

  6. Electron-doping of graphene-based devices by hydrazine

    International Nuclear Information System (INIS)

    A facile and effective technique to tune the electronic properties of graphene is essential to facilitate the flexibility of graphene-based device performances. Here, the use of hydrazine as a solution-processable and effective n-type dopant for graphene is described. By dropping hydrazine solutions at different concentrations on a graphene surface, the Dirac point of graphene can be remarkably tuned. The transport behavior of graphene can be changed from p-type to n-type accordingly, demonstrating the controllable and adjustable doping effect of the hydrazine solutions. Accompanying the Dirac point shift is an enhanced hysteretic behavior of the graphene conductance, indicating an increasing trap state density induced by the hydrazine adsorbates. The electron-doping of graphene by the hydrazine solutions can be additionally confirmed with graphene/p-type silicon heterojunctions. The decrease of the junction current after the hydrazine treatment demonstrates an increase of the junction barrier between graphene and silicon, which is essentially due to the electron-doping of graphene and the resultant upshift of the Fermi level. Finally, partially doped graphene is realized and its electrical property is studied to demonstrate the potential of the hydrazine solutions to selectively electron-doping graphene for future electronic applications

  7. Electron tomography based on a total variation minimization reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Goris, B., E-mail: bart.goris@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Broek, W. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Vision Lab, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Heidari Mezerji, H.; Bals, S. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2012-02-15

    The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms. -- Highlights: Black-Right-Pointing-Pointer A reconstruction algorithm for electron tomography is investigated based on total variation minimization. Black-Right-Pointing-Pointer Missing wedge artefacts are reduced by this algorithm. Black-Right-Pointing-Pointer The reconstruction is easier to segment. Black-Right-Pointing-Pointer More reliable quantitative information can be obtained.

  8. Electron injection and transport mechanism in organic devices based on electron transport materials

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M A; Xu Wei; Khizar-ul-Haq; Zhang Xiaowen; Bai Yu; Jiang, X Y; Zhang, Z L; Zhu, W Q [Department of Materials Science, Shanghai University, Jiading 201800 (China)

    2008-11-21

    Electron injection and transport in organic devices based on electron transport (ET) materials, such as 4,7- diphyenyl-1,10-phenanthroline (Bathophenanthroline BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine BCP) and bipyridyl oxadiazole compound 1,3-bis [2-(2,2'-bipyridin-6-yl)-1,3,4-oxadiazol-5-yl]benzene (Bpy-OXD), have been reported. The devices are composed of ITO/ET materials (BPhen, BCP Bpy-OXD)/cathodes, where cathodes = Au, Al and Ca. Current-voltage characteristics of each ET material are performed as a function of cathodes. We have found that Ca and Al exhibit quite different J-V characteristics compared with the gold (Au) cathode. The current is more than one order of magnitude higher for the Al cathode and more than three orders of magnitude higher for Ca compared with that of the Au cathode at {approx}8 V for all ET materials. This is because of the relatively low energy barrier at the organic/metal interface for Ca and Al cathodes. Electron-only devices with the Au cathode show that the electron transfer limitation is located at the organic/cathode interface and the Fowler-Nordheim mechanism is qualitatively consistent with experimental data at high voltages. With Ca and Al cathodes, electron conduction is preponderant and is bulk limited. A power law dependence J {approx} V{sup m} with m > 2 is consistent with the model of trap-charge limited conduction. The total electron trap density is estimated to be {approx}5 x 10{sup 18} cm{sup -3}. The critical voltage (V{sub c}) is found to be {approx}45 V and is almost independent of the materials.

  9. Atom location using scanning transmission electron microscopy based on electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Full text: The technique of atom location by channelling enhanced microanalysis (ALCHEMI) using cross section data, measured as a function of electron beam orientation, has been widely implemented by many researchers. The accurate application of ALCHEMI, usually based on energy dispersive x-ray analysis (EDX), requires knowledge, from first principles, of the relative delocalization of the inner-shell ionization interaction (see for example Oxley and Allen, 1998; Oxley et al., 1999). Scanning transmission electron microscopy (STEM) based on electron energy loss spectroscopy (EELS) also provides information about the location of atoms of different types within the crystal lattice. Unlike high angle annular dark field (HAADF), EELS provides a unique signal for each atom type. In conjunction with highly focused probes, allowing near atomic resolution, this makes possible, in principle, the application of ALCHEMI like techniques to STEM images to determine the distribution of impurities within the unit cell. The accurate interpretation of STEM results requires that both the inner-shell ionization interaction and resulting ionization cross section or image be correctly modelled. We present model calculations demonstrating the in principle application of ALCHEMI type techniques to STEM images pertinent to EELS. The inner-shell ionisation interaction is modelled using Hartree-Fock wave functions to describe the atomic bound states and Hartree-Slater wave functions to describe the continuum states. The wave function within the crystal is calculated using boundary conditions appropriate for a highly focussed probe (Rossouw and Allen, 2001) and STEM images or ionisation cross sections are simulated using an inelastic cross section formulation that correctly accounts for the contribution from both dynamical electrons and those dechannelled by absorptive scattering processes such as thermal diffuse scattering (TDS). Copyright (2002) Australian Society for Electron Microscopy

  10. Implementing Electronic Tablet-Based Education of Acute Care Patients.

    Science.gov (United States)

    Sawyer, Tenita; Nelson, Monica J; McKee, Vickie; Bowers, Margaret T; Meggitt, Corilin; Baxt, Sarah K; Washington, Delphine; Saladino, Louise; Lehman, E Philip; Brewer, Cheryl; Locke, Susan C; Abernethy, Amy; Gilliss, Catherine L; Granger, Bradi B

    2016-02-01

    Poor education-related discharge preparedness for patients with heart failure is believed to be a major cause of avoidable rehospitalizations. Technology-based applications offer innovative educational approaches that may improve educational readiness for patients in both inpatient and outpatient settings; however, a number of challenges exist when implementing electronic devices in the clinical setting. Implementation challenges include processes for "on-boarding" staff, mediating risks of cross-contamination with patients' device use, and selling the value to staff and health system leaders to secure the investment in software, hardware, and system support infrastructure. Strategies to address these challenges are poorly described in the literature. The purpose of this article is to present a staff development program designed to overcome challenges in implementing an electronic, tablet-based education program for patients with heart failure. PMID:26830181

  11. Electronic Voting Protocol Using Identity-Based Cryptography

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps. PMID:26090515

  12. Electronic Voting Protocol Using Identity-Based Cryptography.

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps. PMID:26090515

  13. MEMS-based flexible reflective analog modulators (FRAM) for projection displays: a technology review and scale-down study

    Science.gov (United States)

    Picard, Francis; Ilias, Samir; Asselin, Daniel; Boucher, Marc-André; Duchesne, François; Jacob, Michel; Larouche, Carl; Vachon, Carl; Niall, Keith K.; Jerominek, Hubert

    2011-02-01

    A MEMS based technology for projection display is reviewed. This technology relies on mechanically flexible and reflective microbridges made of aluminum alloy. A linear array of such micromirrors is combined with illumination and Schlieren optics to produce a pixels line. Each microbridge in the array is individually controlled using electrostatic actuation to adjust the pixels intensities. Results of the simulation, fabrication and characterization of these microdevices are presented. Activation voltages below 250 V with response times below 10 μs were obtained for 25 μm × 25 μm micromirrors. With appropriate actuation voltage waveforms, response times of 5 μs and less are achievable. A damage threshold of the mirrors above 8 kW/cm2 has been evaluated. Development of the technology has produced projector engines demonstrating this light modulation principle. The most recent of these engines is DVI compatible and displays VGA video streams at 60 Hz. Recently applications have emerged that impose more stringent requirements on the dimensions of the MEMS array and associated optical system. This triggered a scale down study to evaluate the minimum micromirror size achievable, the impact of this reduced size on the damage threshold and the achievable minimum size of the associated optical system. Preliminary results of this scale down study are reported. FRAM with active surface as small as 5 μm × 5 μm have been investigated. Simulations have shown that such micromirrors could be activated with 107 V to achieve f-number of 1.25. The damage threshold has been estimated for various FRAM sizes. Finally, design of a conceptual miniaturized projector based on 1000×1 array of 5 μm × 5 μm micromirrors is presented. The volume of this projector concept is about 12 cm3.

  14. MEMS-based flexible reflective analog modulators (FRAM) for projection displays: a technology review and scale-down study

    International Nuclear Information System (INIS)

    A MEMS based technology for projection display is reviewed. This technology relies on mechanically flexible and reflective microbridges made of aluminum alloy. A linear array of such micromirrors is combined with illumination and Schlieren optics to produce a pixels line. Each microbridge in the array is individually controlled using electrostatic actuation to adjust the pixels intensities. Results of the simulation, fabrication and characterization of these microdevices are presented. Activation voltages below 250 V with response times below 10 μs were obtained for 25 μm x 25 μm micromirrors. With appropriate actuation voltage waveforms, response times of 5 μs and less are achievable. A damage threshold of the mirrors above 8 kW/cm2 has been evaluated. Development of the technology has produced projector engines demonstrating this light modulation principle. The most recent of these engines is DVI compatible and displays VGA video streams at 60 Hz. Recently applications have emerged that impose more stringent requirements on the dimensions of the MEMS array and associated optical system. This triggered a scale down study to evaluate the minimum micromirror size achievable, the impact of this reduced size on the damage threshold and the achievable minimum size of the associated optical system. Preliminary results of this scale down study are reported. FRAM with active surface as small as 5 μm x 5 μm have been investigated. Simulations have shown that such micromirrors could be activated with 107 V to achieve f-number of 1.25. The damage threshold has been estimated for various FRAM sizes. Finally, design of a conceptual miniaturized projector based on 1000x1 array of 5 μm x 5 μm micromirrors is presented. The volume of this projector concept is about 12 cm3.

  15. Accelerator physics in ERL based polarized electron ion collider

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yue [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  16. Diffusion of Electronic Medical Record Based Public Hospital Information Systems

    OpenAIRE

    Cho, Kyoung Won; Kim, Seong Min; An, Chang-Ho; Chae, Young Moon

    2015-01-01

    Objectives This study was conducted to evaluate the adoption behavior of a newly developed Electronic Medical Record (EMR)-based information system (IS) at three public hospitals in Korea with a focus on doctors and nurses. Methods User satisfaction scores from four performance layers were analyzed before and two times after the newly develop system was introduced to evaluate the adoption process of the IS with Rogers' diffusion theory. Results The 'intention to use' scores, the most importan...

  17. A nanotube based electron microbeam cellular irradiator for radiobiology research

    OpenAIRE

    Bordelon, David E.; Zhang, Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Zhou, Otto Z.; Chang, Sha

    2008-01-01

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiothera...

  18. Organic electronic memory based on a ferroelectric polymer

    International Nuclear Information System (INIS)

    Measurements of the capacitance of metal-insulator-semiconductor capacitors and the output characteristics of thin film transistors based on poly(3-hexylthiophene) as the active semiconductor and poly(vinylidenefluoride-trifluoroethylene) as the gate insulator show that ferroelectric polarisation in the insulator is stable but that its effect when poled by depletion voltages is partially neutralised by trapping of electrons at or near the semiconductor interface. Nevertheless, the combination of materials is capable of providing an adequate memory function.

  19. Kinetics and mechanisms of the acid-base reaction between NH$_3$ and HCOOH in interstellar ice analogs

    CERN Document Server

    Bergner, Jennifer B; Rajappan, Mahesh; Fayolle, Edith C

    2016-01-01

    Interstellar complex organic molecules (COMs) are commonly observed during star formation, and are proposed to form through radical chemistry in icy grain mantles. Reactions between ions and neutral molecules in ices may provide an alternative cold channel to complexity, as ion-neutral reactions are thought to have low or even no energy barriers. Here we present a study of a the kinetics and mechanisms of a potential ion-generating acid-base reaction between NH$_{3}$ and HCOOH to form the salt NH$_{4}^{+}$HCOO$^{-}$. We observe salt growth at temperatures as low as 15K, indicating that this reaction is feasible in cold environments. The kinetics of salt growth are best fit by a two-step model involving a slow "pre-reaction" step followed by a fast reaction step. The reaction energy barrier is determined to be 70 $\\pm$ 30K with a pre-exponential factor 1.4 $\\pm$ 0.4 x 10$^{-3}$ s$^{-1}$. The pre-reaction rate varies under different experimental conditions and likely represents a combination of diffusion and or...

  20. Fostering Multilateral Involvement in Analog Research

    Science.gov (United States)

    Cromwell, Ronita L.

    2015-01-01

    International collaboration in space flight research is an effective means for conducting investigations and utilizing limited resources to the fullest extent. Through these multilateral collaborations mutual research questions can be investigated and resources contributed by each international partner to maximize the scientific benefits to all parties. Recently the international partners embraced this approach to initiate collaborations in ground-based space flight analog environments. In 2011, the International Analog Research Working Group was established, and later named the International Human Space Flight Analog Research Coordination Group (HANA). Among the goals of this working group are to 1) establish a framework to coordinate research campaigns, as appropriate, to minimize duplication of effort and enhance synergy; 2) define what analogs are best to use for collaborative interests; and 3) facilitate interaction between discipline experts in order to have the full benefit of international expertise. To accomplish these goals, HANA is currently engaged in developing international research campaigns in ground-based analogs. Plans are being made for an international solicitation for proposals to address research of common interest to all international partners. This solicitation with identify an analog environment that will best accommodate the types of investigations requested. Once selected, studies will be integrated into a campaign and implemented at the analog site. Through these combined efforts, research beneficial to all partners will be conducted efficiently to further address human risks of space exploration.

  1. THE ELECTRONIC MARKET LIBERALIZATION IN A KNOWLEDGE BASED ECONOMY

    Directory of Open Access Journals (Sweden)

    Stegăroiu Carina-Elena

    2013-04-01

    Full Text Available In the current context of economic globalization and the advent of the virtual business environment, organizations have registered profound transformations that force companies to reconsider their strategic objectives, especially taking into consideration the opportunities created by the new information and communication technologies. Regardless of their reactive or proactive strategies when facing the changes in the competition, most companies in the developed countries and more and more of the Romanian enterprises are interested in developing technologies and information systems at a intra, inter and extra organizational level, with integrated traits, which are capable to sustain both the managerial process and the traditional functions of the organization. That being said, we herald now the expansion of the electronic commerce or eCommerce, which represents the automatization of the commercial transaction by using information systems and communication technologies. Developing an eCommerce system based on a business-to-business application consists of de-structuring the chain of value in managerial processes and then re-structuring it in order to identify the areas that can be made efficient through electronic means. This study is meant to aid the development of existing models by developing the services in certain less accessible to electronic commerce areas of a knowledge-based economy. As it stands, electronic commerce offers the opportunity of selling products world wide and this increasing the number of potential clients by eliminating the geographical barriers between buyers and seller. Opting for electronic commerce is a solution when the company wants to diversify its services and when it wants to reduce market related costs.

  2. Orbital evidence for clay and acidic sulfate assemblages on Mars based on mineralogical analogs from Rio Tinto, Spain

    Science.gov (United States)

    Kaplan, Hannah H.; Milliken, Ralph E.; Fernández-Remolar, David; Amils, Ricardo; Robertson, Kevin; Knoll, Andrew H.

    2016-09-01

    Outcrops of hydrated minerals are widespread across the surface of Mars, with clay minerals and sulfates being commonly identified phases. Orbitally-based reflectance spectra are often used to classify these hydrated components in terms of a single mineralogy, although most surfaces likely contain multiple minerals that have the potential to record local geochemical conditions and processes. Reflectance spectra for previously identified deposits in Ius and Melas Chasma within the Valles Marineris, Mars, exhibit an enigmatic feature with two distinct absorptions between 2.2 and 2.3 μm. This spectral 'doublet' feature is proposed to result from a mixture of hydrated minerals, although the identity of the minerals has remained ambiguous. Here we demonstrate that similar spectral doublet features are observed in airborne, field, and laboratory reflectance spectra of rock and sediment samples from Rio Tinto, Spain. Combined visible-near infrared reflectance spectra and X-ray diffraction measurements of these samples reveal that the doublet feature arises from a mixture of Al-phyllosilicate (illite or muscovite) and jarosite. Analyses of orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) shows that the martian spectral equivalents are also consistent with mixtures of Al-phyllosilicates and jarosite, where the Al-phyllosilicate may also include kaolinite and/or halloysite. A case study for a region within Ius Chasma demonstrates that the relative proportions of the Al-phyllosilicate(s) and jarosite vary within one stratigraphic unit as well as between stratigraphic units. The former observation suggests that the jarosite may be a diagenetic (authigenic) product and thus indicative of local pH and redox conditions, whereas the latter observation may be consistent with variations in sediment flux and/or fluid chemistry during sediment deposition.

  3. Atomic Electronic Contract Protocol Based on Convertible Signature

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-chun; WANG Li-na; ZHANG Huan-guo

    2005-01-01

    A new class of atomicity, namely contract atomicity is presented. A new technical strategy based on convertible signature and two-phase commitment is proposed for implementing atomicity of electronic contract protocol. A new atomic contract signing protocol is given out by using ElGamal-like convertible undeniable signature and commitment of conversion key, and another new atomic contract signing protocol is brought forward by using RSA-based convertible undeniable signature scheme and commitment of conversion key.These two new protocols are proved to be of atomicity, fairness, privacy, non-repudiation.

  4. Pressure induced phase transition behaviour in -electron based dialuminides

    Indian Academy of Sciences (India)

    P Ch Sahu; N V Chandra Shekar

    2000-05-01

    The rare-earth and actinide based compounds are endowed with several exotic physical and chemical properties due to the presence of -electrons. These properties exhibit interesting changes under the action of various thermodynamic fields and hence continues to be a subject of extensive research. For instance, under pressure, the nature of -electrons can be changed from localized to itinerant, leading to a variety of changes in their structural, physical and chemical properties. The present review on the high pressure phase transition behaviour of dialuminides of rare earths and actinides is an outcome of research in our laboratory during the last five years using a unique combination of a Guinier diffractometer and a diamond anvil cell built in-house. To bring out the correlations between the compressibility and structural behaviour with the electronic structure, we have also carried out electronic structure calculation. Further, the usefulness of Villars' three parameter structure maps in predicting pressure induced structural transitions has been explored and this has been illustrated with the available phase transition data.

  5. A molecularly based theory for electron transfer reorganization energy

    International Nuclear Information System (INIS)

    Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory

  6. Advanced electron crystallography through model-based imaging.

    Science.gov (United States)

    Van Aert, Sandra; De Backer, Annick; Martinez, Gerardo T; den Dekker, Arnold J; Van Dyck, Dirk; Bals, Sara; Van Tendeloo, Gustaaf

    2016-01-01

    The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy. PMID:26870383

  7. RFID-based Electronic Identity Security Cloud Platform in Cyberspace

    Directory of Open Access Journals (Sweden)

    Bing Chen

    2012-07-01

    Full Text Available With the moving development of networks, especially Internet of Things, electronic identity administration in cyberspace is becoming more and more important. And personal identity management in cyberspace associated with individuals in reality has been one significant and urgent task for the further development of information construction in China. So this paper presents a RFID-based electronic identity security cloud platform in cyberspace to implement an efficient security management of cyber personal identity, and designs and realizes a strong and pervasive security cloud service platform, and discusses key technology including security authentication mechanism for the electronic identity card, super high frequency RFID with eID cards, multilevel privacy protection mechanism, security cloud service, security isolation and single-oriented transmission, and boundary security gateway protection, and it can well apply to personal identity management with virtual roles of citizens in cyberspace such as E-Government and E-Business, and the electronic identity security platform has been primary implemented and achieved good effects in actual applications.

  8. Digital and analog communication systems

    Science.gov (United States)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  9. Analogical Reasoning in Geometry Education

    Science.gov (United States)

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  10. Electronic shift register memory based on molecular electron-transfer reactions

    International Nuclear Information System (INIS)

    The design of a shift register memory at the molecular level is described in detail. The memory elements are based on a chain of electron-transfer molecules incorporated on a very large scale integrated (VLSI) substrate, and the information is shifted by photoinduced electron-transfer reactions. The design requirements for such a system are discussed, and several realistic strategies for synthesizing these systems are presented. The immediate advantage of such a hybrid molecular/VLSI device would arise from the possible information storage density. The prospect of considerable savings of energy per bit processed also exists. This molecular shift register memory element design solves the conceptual problems associated with integrating molecular size components with larger (micron) size features on a chip

  11. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  12. Analog Optical Computing Primitives in Silicon Photonics

    CERN Document Server

    Jiang, Yunshan; Jalali, Bahram

    2015-01-01

    Optical computing accelerators may help alleviate bandwidth and power consumption bottlenecks in electronics. We show an approach to implementing logarithmic-type analog co-processors in silicon photonics and use it to perform the exponentiation operation. The function is realized by exploiting nonlinear-absorption-enhanced Raman amplification saturation in a silicon waveguide.

  13. Analog optical computing primitives in silicon photonics

    Science.gov (United States)

    Jiang, Yunshan; DeVore, Peter T. S.; Jalali, Bahram

    2016-03-01

    Optical computing accelerators may help alleviate bandwidth and power consumption bottlenecks in electronics. We show an approach to implementing logarithmic-type analog co-processors in silicon photonics and use it to perform the exponentiation operation. The function is realized by exploiting nonlinear-absorption-enhanced Raman amplification saturation in a silicon waveguide.

  14. Thin-film chemical sensors based on electron tunneling

    Science.gov (United States)

    Khanna, S. K.; Lambe, J.; Leduc, H. G.; Thakoor, A. P.

    1985-01-01

    The physical mechanisms underlying a novel chemical sensor based on electron tunneling in metal-insulator-metal (MIM) tunnel junctions were studied. Chemical sensors based on electron tunneling were shown to be sensitive to a variety of substances that include iodine, mercury, bismuth, ethylenedibromide, and ethylenedichloride. A sensitivity of 13 parts per billion of iodine dissolved in hexane was demonstrated. The physical mechanisms involved in the chemical sensitivity of these devices were determined to be the chemical alteration of the surface electronic structure of the top metal electrode in the MIM structure. In addition, electroreflectance spectroscopy (ERS) was studied as a complementary surface-sensitive technique. ERS was shown to be sensitive to both iodine and mercury. Electrolyte electroreflectance and solid-state MIM electroreflectance revealed qualitatively the same chemical response. A modified thin-film structure was also studied in which a chemically active layer was introduced at the top Metal-Insulator interface of the MIM devices. Cobalt phthalocyanine was used for the chemically active layer in this study. Devices modified in this way were shown to be sensitive to iodine and nitrogen dioxide. The chemical sensitivity of the modified structure was due to conductance changes in the active layer.

  15. The effects of analogy-based instruction on concept learning and retention in a non-formal coral reef ecology program

    Science.gov (United States)

    Brylske, Alexander Frederick

    While a number of instructional models focus on the use of analogies, research into their effectiveness in enhancing comprehension and retention of scientific concepts, particularly involving adult learners, has been limited. The purpose of this study was to determine the efficacy of using the common teaching strategy for comparing the function of a coral reef to that of a city by using an analogy-based instructional model termed FAR. The training program entitled "Marine Resource Management for Dive Professionals" (MRMDP) was developed for this study. It was targeted to professionals in the recreational scuba industry to improve their understanding of coal reef ecology, as well as orient them to pertinent marine resource management issues, and promote environmentally-responsible attitudes and diving practices among their clients. A quasi-experimental pre-post-delayed posttest control group design was used to explore five research questions and corresponding hypotheses. A 55-item researcher-developed test of coral reef ecology was administered pre and post instruction. The delayed posttest was self-administered by the subjects three weeks after course completion. Data on seven experiential variables hypothesized as research factors were collected. Ten MRMPD courses were taught in seven nations, involving 194 subjects (85 subjects in four control courses, 109 in six treatment course). The results were analyzed using multiple regression/correlation (MRC) techniques to determine: (1) any significant relationship between pretest performance and experiential variables, (2) treatment versus control group posttest performance, and (3) treatment versus control group delayed posttest performance. Within the treatment group, learning gains and retention were determined by t-test analysis. Results indicated: (1) all research factors except one were significant predictors of pretest scores in the presence of the covariate; (2) no significant difference was found between

  16. Agent-based services for B2B electronic commerce

    Science.gov (United States)

    Fong, Elizabeth; Ivezic, Nenad; Rhodes, Tom; Peng, Yun

    2000-12-01

    The potential of agent-based systems has not been realized yet, in part, because of the lack of understanding of how the agent technology supports industrial needs and emerging standards. The area of business-to-business electronic commerce (b2b e-commerce) is one of the most rapidly developing sectors of industry with huge impact on manufacturing practices. In this paper, we investigate the current state of agent technology and the feasibility of applying agent-based computing to b2b e-commerce in the circuit board manufacturing sector. We identify critical tasks and opportunities in the b2b e-commerce area where agent-based services can best be deployed. We describe an implemented agent-based prototype system to facilitate the bidding process for printed circuit board manufacturing and assembly. These activities are taking place within the Internet Commerce for Manufacturing (ICM) project, the NIST- sponsored project working with industry to create an environment where small manufacturers of mechanical and electronic components may participate competitively in virtual enterprises that manufacture printed circuit assemblies.

  17. Synthesis, structure-activity relationship and molecular docking of cyclohexenone based analogous as potent non-nucleoside reverse-transcriptase inhibitors

    Science.gov (United States)

    Nazar, Muhammad Faizan; Abdullah, Muhammad Imran; Badshah, Amir; Mahmood, Asif; Rana, Usman Ali; Khan, Salah Ud-Din

    2015-04-01

    The chalcones core in compounds is advantageously chosen effective synthons, which offer exciting perspectives in biological and pharmacological research. The present study reports the successful development of eight new cyclohexenone based anti-reverse transcriptase analogous using rational drug design synthesis principles. These new cyclohexenone derivatives (CDs) were synthesized by following a convenient route of Robinson annulation, and the molecular structure of these CDs were later confirmed by various analytical techniques such as 1H NMR, 13C NMR, FT-IR, UV-Vis spectroscopy and mass spectrometry. All the synthesized compounds were screened theoretically and experimentally against reverse transcriptase (RT) and found potentially active reverse transcriptase (RT) inhibitors. Of the compounds studied, the compound 2FC4 showed high interaction with RT at non-nucleoside binding site, contributing high free binding energy (ΔG -8.01 Kcal) and IC50 (0.207 μg/ml), respectively. Further results revealed that the compounds bearing more halogen groups, with additional hydrophobic character, offered superior anti-reverse transcriptase activity as compared to rest of compounds. It is anticipate that the present study would be very useful for the selection of potential reverse transcriptase inhibitors featuring inclusive pharmacological profiles.

  18. Research of AC Analog Modulated Based on LVDT/RVDT%基于LVDT/RVDT的交流模拟量解调方法研究

    Institute of Scientific and Technical Information of China (English)

    魏婷; 夏德天

    2013-01-01

    Differential Transformer Type Sensor is an electromagnetic switch unit widely used in the flight control system. Real- time and accurate fault identification and detection of the sensor output is critical. This paper researches a new method of AC analog monitored and modulated based on LVDT/RVDT Sensor, and gives the result of the verification. The method is very effective at demodulating and monitoring the sensor output, which improves the security and reliability of the system dramatically.%差动变压器式传感器是在飞行控制系统中广泛采用的电磁式变换元件,实时准确地对传感器输出进行识别和故障检测非常关键.研究了一种基于LVDT/RVDT传感器的交流模拟量的解调和监控方法,并进行测试验证,方法可有效地对传感器的输出进行解调和监控,提高系统的安全可靠性.

  19. Web based electronic log book for Indus-2

    International Nuclear Information System (INIS)

    Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India has a 20 MeV Microtron injector, a 450/700 MeV Booster Synchrotron, a 450 MeV Storage Ring Indus-1 and another 2.5 GeV Storage Ring Indus-2. Both the machines are national facilities and are run round the clock to provide synchrotron radiation to users as well as carrying out machine related studies. In a multi accelerator complex like this, an effective system for electronically recording experimental data, machine status, events etc is considered essential. Considering the advantages of Internet technologies, a first version of web based Electronic Logbook (Elogbook) has been developed using HTML, JavaScript, java servlets and SQL database. This Elogbook will provide convenient way to review machine performance, help in problem diagnosis and improve communications among working teams. (author)

  20. Design of Wireless Electronic Stethoscope Based on Zigbee

    Directory of Open Access Journals (Sweden)

    Kadam Patil D.D

    2012-02-01

    Full Text Available Heart sound stethoscope is primary stage to access diseases. In this paper design of an electronic stethoscope with the functions of wireless transmission is discussed. This electronic stethoscope based on embedded processor. The data can be transmitted through wireless transmission using Zigbee module. A microphone is used to pick up the sound of the heart beat. Acoustic stethoscope can be changed into a digital stethoscope by inserting an electric capacity microphone into its head. The signal is processed and amplified to play with or without earphone. Heart sounds are processed, sampled and sent wirelessly using Zigbee module so that multiple doctors can do auscultation. PC connectivity is provided through serial port where from audio and video can be made available through LAN and internet for telemedicine consultation. Heart beat signals are sensed, sent, displayed, monitored, stored, reviewed, and analysed with ease.

  1. Design of wireless electronic stethoscope based on zigbee

    CERN Document Server

    Patil, D D Kadam

    2012-01-01

    Heart sound stethoscope is primary stage to access diseases. In this paper design of an electronic stethoscope with the functions of wireless transmission is discussed. This electronic stethoscope based on embedded processor. The data can be transmitted through wireless transmission using Zigbee module. A microphone is used to pick up the sound of the heart beat. Acoustic stethoscope can be changed into a digital stethoscope by inserting an electric capacity microphone into its head. The signal is processed and amplified to play with or without earphone. Heart sounds are processed, sampled and sent wirelessly using Zigbee module so that multiple doctors can do auscultation. PC connectivity is provided through serial port where from audio and video can be made available through LAN and internet for telemedicine consultation. Heart beat signals are sensed, sent, displayed, monitored, stored, reviewed, and analysed with ease.

  2. Two-dimensional materials based transparent flexible electronics

    Science.gov (United States)

    Yu, Lili; Ha, Sungjae; El-Damak, Dina; McVay, Elaine; Ling, Xi; Chandrakasan, Anantha; Kong, Jing; Palacios, Tomas

    2015-03-01

    Two-dimensional (2D) materials have generated great interest recently as a set of tools for electronics, as these materials can push electronics beyond traditional boundaries. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. These thin, lightweight, bendable, highly rugged and low-power devices may bring dramatic changes in information processing, communications and human-electronic interaction. In this report, for the first time, we demonstrate two complex transparent flexible systems based on molybdenum disulfide (MoS2) grown by chemical vapor method: a transparent active-matrix organic light-emitting diode (AMOLED) display and a MoS2 wireless link for sensor nodes. The 1/2 x 1/2 square inch, 4 x 5 pixels AMOLED structures are built on transparent substrates, containing MoS2 back plane circuit and OLEDs integrated on top of it. The back plane circuit turns on and off the individual pixel with two MoS2 transistors and a capacitor. The device is designed and fabricated based on SPICE simulation to achieve desired DC and transient performance. We have also demonstrated a MoS2 wireless self-powered sensor node. The system consists of as energy harvester, rectifier, sensor node and logic units. AC signals from the environment, such as near-field wireless power transfer, piezoelectric film and RF signal, are harvested, then rectified into DC signal by a MoS2 diode. CIQM, CICS, SRC.

  3. Analogical Learning and Automated Rule Constructions

    Institute of Scientific and Technical Information of China (English)

    周哈阳

    1991-01-01

    This paper describes some experiments of analogical learning and automated rule construction.The present investigation focuses on knowledge acquisition,learning by analyogy,and knowledge retention.The developed system initially learns from scratch,gradually acquires knowledge from its environment through trial-and-error interaction,incrementally augments its knowledge base,and analogically solves new tasks in a more efficient and direct manner.

  4. A review of EBMT using proportional analogies

    OpenAIRE

    Somers, Harold; Dandapat, Sandipan; Naskar, Sudip Kumar

    2009-01-01

    Some years ago a number of papers reported an experimental implementation of Example Based Machine Translation (EBMT) using Proportional Analogy. This approach, a type of analogical learning, was attractive because of its simplicity; and the papers reported considerable success with the method. This paper reviews what we believe to be the totality of research reported using this method, as an introduction to our own experiments in this framework, reported in a companion paper. We report first...

  5. Automated Integrated Analog Filter Design Issues

    OpenAIRE

    Karolis Kiela; Romualdas Navickas

    2015-01-01

    An analysis of modern automated integrated analog circuits design methods and their use in integrated filter design is done. Current modern analog circuits automated tools are based on optimization algorithms and/or new circuit generation methods. Most automated integrated filter design methods are only suited to gmC and switched current filter topologies. Here, an algorithm for an active RC integrated filter design is proposed, that can be used in automated filter designs. The algorithm is t...

  6. Quantum Electric Circuits Analogous to Ballistic Conductors

    OpenAIRE

    Dragoman, Daniela

    2007-01-01

    The conductance steps in a constricted two-dimensional electron gas and the minimum conductivity in graphene are related to a new uncertainty relation between electric charge and conductance in a quantized electric circuit that mimics the electric transport in mesoscopic systems. This uncertainty relation makes specific use of the discreteness of electric charge. Quantum electric circuits analogous to both constricted two-dimensional electron gas and graphene are introduced. In the latter cas...

  7. The CMS Fast Beams Condition Monitor Backend Electronics based on MicroTCA technology

    CERN Document Server

    Zagozdzinska, Agnieszka Anna

    2015-01-01

    The Fast Beams Condition Monitor (BCM1F), upgraded for LHC Run II, is one sub-system of the Beam Radiation Instrumentation and Luminosity Project of the CMS experiment. It is based on 24 single crystal CVD diamond sensors. Each sensor is metallised with two pads, being read out by a dedicated fast frontend chip produced in 130 nm CMOS technology. Signals for real time monitoring are processed by custom-made back-end electronics to measure separately rates corresponding to LHC collision products, machine induced background and residual activation exploiting different arrival times. The system is built in MicroTCA technology and uses high speed analog-to-digital converters. The data processing module designed for the FPGA allows a distinguishing of collision and machine induced background, both synchronous to the LHC clock, from the residual activation products. In operational modes of high rates, consecutive events, spaced in time by less than 12.5 ns, may partially overlap. Hence, novel signal processing tec...

  8. Low-voltage coherent electron imaging based on a single-atom electron

    CERN Document Server

    Chang, Wei-Tse; Hsu, Wei-Hao; Chang, Mu-Tung; Chen, Yi-Sheng; Hwu, En-Te; Hwang, Ing-Shouh

    2015-01-01

    It has been a general trend to develop low-voltage electron microscopes due to their high imaging contrast of the sample and low radiation damage. Atom-resolved transmission electron microscopes with voltages as low as 15-40 kV have been demonstrated. However, achieving atomic resolution at voltages lower than 10 kV is extremely difficult. An alternative approach is coherent imaging or phase retrieval imaging, which requires a sufficiently coherent source and an adequately small detection area on the sample as well as the detection of high-angle diffracted patterns with a sufficient resolution. In this work, we propose several transmission-type schemes to achieve coherent imaging of thin materials (less than 5 nm thick) with atomic resolution at voltages lower than 10 kV. Experimental schemes of both lens-less and lens-containing designs are presented and the advantages and challenges of these schemes are discussed. Preliminary results based on a highly coherent single-atom electron source are presented. The ...

  9. Carbon nanotube based pressure sensor for flexible electronics

    International Nuclear Information System (INIS)

    Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate

  10. Carbon nanotube based pressure sensor for flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    So, Hye-Mi [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of); Sim, Jin Woo [Advanced Nano Technology Ltd., Seoul 132-710 (Korea, Republic of); Kwon, Jinhyeong [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Yun, Jongju; Baik, Seunghyun [SKKU Advanced Institute of Nanotechnology (SAINT), Department of Energy Science and School of Mechanical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Chang, Won Seok, E-mail: paul@kimm.re.kr [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of)

    2013-12-15

    Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate.

  11. Towards analogy in toponyms

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Pavel

    Cluj : Mega, 2013 - (Felecan, O.), s. 379-383 ISBN 978-606-543-343-4. [Name and Naming /2./ Onomastics in Contemporary Public Space. Baia Mare (RO), 09.05.2013-11.05.2013] R&D Projects: GA ČR GPP406/12/P600 Institutional support: RVO:68378092 Keywords : onomastics * toponyms * analogy Subject RIV: AI - Linguistics

  12. Novel analog switching circuit for van der Pauw measurements

    OpenAIRE

    David, T.; Molchadsky, I.; Somechi, A.; Rosenbaum, R.

    2005-01-01

    A simple electronic circuit is described using four common and very inexpensive analog multiplexer/demultiplexer chips. These analog switches are used to select eight different wiring configurations to a van der Pauw sample. Several interfacing schemes to a PC are suggested. The van der Pauw resistivity and Hall voltage expressions are also summarized.

  13. DOCCⅡ-based electronically tunable current-mode biquadratic filters

    Institute of Scientific and Technical Information of China (English)

    Wang Weidong

    2005-01-01

    A complete state variable current-mode biquadratic filter built by duo-output CCⅡ (DOCCⅡ) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCⅡ. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.

  14. Performance analysis of gamma ray spectrometric parameters on digital signal and analog signal processing based MCA systems using NaI(Tl) detector

    Energy Technology Data Exchange (ETDEWEB)

    Kukreti, B.M., E-mail: bharatkuk@gmail.com [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India); Sharma, G.K. [Atomic Minerals Directorate for Exploration and Research, Physics Laboratory, Department of Atomic Energy, Nongmynsong, AMD Complex, Shillong, Meghalaya 793019 (India)

    2012-05-15

    Accurate and speedy estimations of ppm range uranium and thorium in the geological and rock samples are most useful towards ongoing uranium investigations and identification of favorable radioactive zones in the exploration field areas. In this study with the existing 5 in. Multiplication-Sign 4 in. NaI(Tl) detector setup, prevailing background and time constraints, an enhanced geometrical setup has been worked out to improve the minimum detection limits for primordial radioelements K{sup 40}, U{sup 238} and Th{sup 232}. This geometrical setup has been integrated with the newly introduced, digital signal processing based MCA system for the routine spectrometric analysis of low concentration rock samples. Stability performance, during the long counting hours, for digital signal processing MCA system and its predecessor NIM bin based MCA system has been monitored, using the concept of statistical process control. Monitored results, over a time span of few months, have been quantified in terms of spectrometer's parameters such as Compton striping constants and Channel sensitivities, used for evaluating primordial radio element concentrations (K{sup 40}, U{sup 238} and Th{sup 232}) in geological samples. Results indicate stable dMCA performance, with a tendency of higher relative variance, about mean, particularly for Compton stripping constants. - Highlights: Black-Right-Pointing-Pointer Geometrical enhancement for ppm range primordial radio elemental determination. Black-Right-Pointing-Pointer Experimental constraints include detector setup, background and counting time. Black-Right-Pointing-Pointer Gamma spectrometric performance monitored on digital and analog MCA systems. Black-Right-Pointing-Pointer Study indicates higher variance of Compton stripping constants on digital MCA system.

  15. Electron transport in gold colloidal nanoparticle-based strain gauges

    International Nuclear Information System (INIS)

    A systematic approach for understanding the electron transport mechanisms in resistive strain gauges based on assemblies of gold colloidal nanoparticles (NPs) protected by organic ligands is described. The strain gauges were fabricated from parallel micrometer wide wires made of 14 nm gold (Au) colloidal NPs on polyethylene terephthalate substrates, elaborated by convective self-assembly. Electron transport in such devices occurs by inter-particle electron tunneling through the tunnel barrier imposed by the organic ligands protecting the NPs. This tunnel barrier was varied by changing the nature of organic ligands coating the nanoparticles: citrate (CIT), phosphines (BSPP, TDSP) and thiols (MPA, MUDA). Electro-mechanical tests indicate that only the gold NPs protected by phosphine and thiol ligands yield high gauge sensitivity. Temperature-dependent resistance measurements are explained using the ‘regular island array model’ that extracts transport parameters, i.e., the tunneling decay constant β and the Coulomb charging energy EC. This reveals that the Au-CIT nanoparticle assemblies exhibit a behavior characteristic of a strong-coupling regime, whereas those of Au-BSPP, Au-TDSP, Au-MPA and Au-MUDA nanoparticles manifest a weak-coupling regime. A comparison of the parameters extracted from the two methods indicates that the most sensitive gauges in the weak-coupling regime feature the highest β. Moreover, the EC values of these 14 nm NPs cannot be neglected in determining the β values. (paper)

  16. An Electronic Library-Based Learning Environment for Supporting Web-Based Problem-Solving Activities

    Science.gov (United States)

    Tsai, Pei-Shan; Hwang, Gwo-Jen; Tsai, Chin-Chung; Hung, Chun-Ming; Huang, Iwen

    2012-01-01

    This study aims to develop an electronic library-based learning environment to support teachers in developing web-based problem-solving activities and analyzing the online problem-solving behaviors of students. Two experiments were performed in this study. In study 1, an experiment on 103 elementary and high school teachers (the learning activity…

  17. Diamond-based heat spreaders for power electronic packaging applications

    Science.gov (United States)

    Guillemet, Thomas

    As any semiconductor-based devices, power electronic packages are driven by the constant increase of operating speed (higher frequency), integration level (higher power), and decrease in feature size (higher packing density). Although research and innovation efforts have kept these trends continuous for now more than fifty years, the electronic packaging technology is currently facing a challenge that must be addressed in order to move toward any further improvements in terms of performances or miniaturization: thermal management. Thermal issues in high-power packages strongly affect their reliability and lifetime and have now become one of the major limiting factors of power modules development. Thus, there is a strong need for materials that can sustain higher heat flux levels while safely integrating into the electronic package architecture. In such context, diamond is an attractive candidate because of its outstanding thermal conductivity, low thermal expansion, and high electrical resistivity. Its low heat capacity relative to metals such as aluminum or copper makes it however preferable for heat spreading applications (as a heat-spreader) rather than for dissipating the heat flux itself (as a heat sink). In this study, a dual diamond-based heat-spreading solution is proposed. Polycrystalline diamond films were grown through laser-assisted combustion synthesis on electronic substrates (in the U.S) while, in parallel, diamond-reinforced copper-matrix composite films were fabricated through tape casting and hot pressing (in France). These two types of diamond-based heat-spreading films were characterized and their microstructure and chemical composition were related to their thermal performances. Particular emphasize was put on the influence of interfaces on the thermal properties of the materials, either inside a single material (grain boundaries) or between dissimilar materials (film/substrate interface, matrix/reinforcement interface). Finally, the packaging

  18. FITPix COMBO—Timepix detector with integrated analog signal spectrometric readout

    Science.gov (United States)

    Holik, M.; Kraus, V.; Georgiev, V.; Granja, C.

    2016-02-01

    The hybrid semiconductor pixel detector Timepix has proven a powerful tool in radiation detection and imaging. Energy loss and directional sensitivity as well as particle type resolving power are possible by high resolution particle tracking and per-pixel energy and quantum-counting capability. The spectrometric resolving power of the detector can be further enhanced by analyzing the analog signal of the detector common sensor electrode (also called back-side pulse). In this work we present a new compact readout interface, based on the FITPix readout architecture, extended with integrated analog electronics for the detector's common sensor signal. Integrating simultaneous operation of the digital per-pixel information with the common sensor (called also back-side electrode) analog pulse processing circuitry into one device enhances the detector capabilities and opens new applications. Thanks to noise suppression and built-in electromagnetic interference shielding the common hardware platform enables parallel analog signal spectroscopy on the back side pulse signal with full operation and read-out of the pixelated digital part, the noise level is 600 keV and spectrometric resolution around 100 keV for 5.5 MeV alpha particles. Self-triggering is implemented with delay of few tens of ns making use of adjustable low-energy threshold of the particle analog signal amplitude. The digital pixelated full frame can be thus triggered and recorded together with the common sensor analog signal. The waveform, which is sampled with frequency 100 MHz, can be recorded in adjustable time window including time prior to the trigger level. An integrated software tool provides control, on-line display and read-out of both analog and digital channels. Both the pixelated digital record and the analog waveform are synchronized and written out by common time stamp.

  19. FITPix COMBO—Timepix detector with integrated analog signal spectrometric readout

    International Nuclear Information System (INIS)

    The hybrid semiconductor pixel detector Timepix has proven a powerful tool in radiation detection and imaging. Energy loss and directional sensitivity as well as particle type resolving power are possible by high resolution particle tracking and per-pixel energy and quantum-counting capability. The spectrometric resolving power of the detector can be further enhanced by analyzing the analog signal of the detector common sensor electrode (also called back-side pulse). In this work we present a new compact readout interface, based on the FITPix readout architecture, extended with integrated analog electronics for the detector's common sensor signal. Integrating simultaneous operation of the digital per-pixel information with the common sensor (called also back-side electrode) analog pulse processing circuitry into one device enhances the detector capabilities and opens new applications. Thanks to noise suppression and built-in electromagnetic interference shielding the common hardware platform enables parallel analog signal spectroscopy on the back side pulse signal with full operation and read-out of the pixelated digital part, the noise level is 600 keV and spectrometric resolution around 100 keV for 5.5 MeV alpha particles. Self-triggering is implemented with delay of few tens of ns making use of adjustable low-energy threshold of the particle analog signal amplitude. The digital pixelated full frame can be thus triggered and recorded together with the common sensor analog signal. The waveform, which is sampled with frequency 100 MHz, can be recorded in adjustable time window including time prior to the trigger level. An integrated software tool provides control, on-line display and read-out of both analog and digital channels. Both the pixelated digital record and the analog waveform are synchronized and written out by common time stamp

  20. Analog data transmission via fiber optics

    International Nuclear Information System (INIS)

    In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission

  1. Design challenges of EO polymer based leaky waveguide deflector for 40 Gs/s all-optical analog-to-digital converters

    Science.gov (United States)

    Hadjloum, Massinissa; El Gibari, Mohammed; Li, Hongwu; Daryoush, Afshin S.

    2016-08-01

    Design challenges and performance optimization of an all-optical analog-to-digital converter (AOADC) is presented here. The paper addresses both microwave and optical design of a leaky waveguide optical deflector using electro-optic (E-O) polymer. The optical deflector converts magnitude variation of the applied RF voltage into variation of deflection angle out of a leaky waveguide optical beam using the linear E-O effect (Pockels effect) as part of the E-O polymer based optical waveguide. This variation of deflection angle as result of the applied RF signal is then quantized using optical windows followed by an array of high-speed photodetectors. We optimized the leakage coefficient of the leaky waveguide and its physical length to achieve the best trade-off between bandwidth and the deflected optical beam resolution, by improving the phase velocity matching between lightwave and microwave on one hand and using pre-emphasis technique to compensate for the RF signal attenuation on the other hand. In addition, for ease of access from both optical and RF perspective, a via-hole less broad bandwidth transition is designed between coplanar pads and coupled microstrip (CPW-CMS) driving electrodes. With the best reported E-O coefficient of 350 pm/V, the designed E-O deflector should allow an AOADC operating over 44 giga-samples-per-seconds with an estimated effective resolution of 6.5 bits on RF signals with Nyquist bandwidth of 22 GHz. The overall DC power consumption of all components used in this AOADC is of order of 4 W and is dominated by power consumption in the power amplifier to generate a 20 V RF voltage in 50 Ohm system. A higher sampling rate can be achieved at similar bits of resolution by interleaving a number of this elementary AOADC at the expense of a higher power consumption.

  2. Electron-ion plasma modification of Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yurii, E-mail: yufi55@mail.ru [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Rygina, Mariya, E-mail: l-7755me@mail.ru [National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Petrikova, Elizaveta, E-mail: elizmarkova@yahoo.com; Krysina, Olga, E-mail: krysina-82@mail.ru; Teresov, Anton, E-mail: tad514@sibmail.com [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); Ivanova, Olga, E-mail: ivaov@mail.ru; Ikonnikova, Irina, E-mail: irina-ikonnikova@yandex.ru [Tomsk State University of Architecture and Building, Tomsk, 634002, Russia, Tomsk, 2 Solyanaya Sq (Russian Federation)

    2016-01-15

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm{sup 2}) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa.

  3. Photon-Electron Interactions in Graphene-Based Heterojunctions

    Science.gov (United States)

    Liu, Fangze

    Graphene, a single layer of carbon atoms arranged in honeycomb lattice, has been one of the most attractive materials for fundamental and applied research in the past decade. Its unique electronic, optical, thermal, chemical and mechanical properties have lead to the discovery of new physics and many promising applications. In particular, research on photon-electron interaction in graphene-based heterojunctions has revealed a new route to design photoactive devices. In this thesis, I present our work on the synthesis of graphene by chemical vapor deposition (CVD) and the study of graphene-based optoelectronic devices. In addition to the conventional synthesis of graphene on copper (Cu) foils, we also present the CVD synthesis of graphene on a new substrate: palladium (Pd). Especially, we performed detailed study of the nucleation, evolution and morphology of graphene growth on Pd substrate. It helps us to understand the growth reaction mechanism and achieve controllable synthesis of graphene from single layer to multiple layers with different morphologies. We then studied the broadband and ultrasensitive photocurrent and photovoltage response of graphene/silicon (Si) Schottky diodes. For the same architecture, we identified a new photoconductive mode with ultra high photoconductive gain, namely "quantum carrier reinvestment (QCR)". A gain exceeding 107 A/W was demonstrated. The underlying physics of photon-electron interactions in these junctions were studied by a combination of optical characterization tools including Raman spectroscopy, UV-Vis spectroscopy and scanning optical microscopy. The results obtained have been discussed in the framework of the unique electronic band structure, density states, and mobility of graphene, along with the manner in witch photoexcited carrier behave under various externally tuned parameters. We also systematically studied the optimization of performance of graphene/Si and thin transparent graphite/Si junction solar cells and

  4. Electron-ion plasma modification of Al-based alloys

    International Nuclear Information System (INIS)

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm2) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa

  5. USW area analogs

    OpenAIRE

    Everett, Keith R.

    2005-01-01

    The purpose of this project is to investigate the feasibility of and methodology for the development of a set of environmental analogs of operational Undersea Warfare (USW) areas within fleet training areas. It is primarily a discussion of the identification of parameters that characterize the tactical USW environment, prioritization of these parameters, identification of existing databases that contain these parameters and an outline of the processes required to extract the desired data fro...

  6. Analogy, Explanation, and Proof

    Directory of Open Access Journals (Sweden)

    John eHummel

    2014-11-01

    Full Text Available People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic whose truth was not even known prior to the existence of the explanation (proof. What do the cognitive operations underlying the (inductive inference that the milk is sour have in common with the (deductive proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This small-seeming difference poses a challenge to the task of marshaling our understanding of analogical reasoning in the service of understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence.

  7. ADSL Analog Front End

    OpenAIRE

    Stojković, Nino

    2006-01-01

    In this paper the Asymmetric Digital Subscriber Line (ADSL) analog front end (AFE) designs are described and compared. AFE is the part of ADSL modems most responsible for quality signal transmission over phone wires. It can be divided into the transmitting path (TX) circuitry, the receiving path (RX) circuitry and the hybrid network and transformer. The operations and realizations of each functional block are presented. There are the D/A converter, the filter and the line driver in the TX pat...

  8. Analog Signal Processing

    OpenAIRE

    Caloz, Christophe; Gupta, Shulabh; Zhang, Qingfeng; Nikfal, Babak

    2013-01-01

    Analog signal processing (ASP) is presented as a systematic approach to address future challenges in high speed and high frequency microwave applications. The general concept of ASP is explained with the help of examples emphasizing basic ASP effects, such as time spreading and compression, chirping and frequency discrimination. Phasers, which represent the core of ASP systems, are explained to be elements exhibiting a frequency-dependent group delay response, and hence a nonlinear phase resp...

  9. Probing flexibility in porphyrin-based molecular wires using double electron electron resonance.

    Science.gov (United States)

    Lovett, Janet E; Hoffmann, Markus; Cnossen, Arjen; Shutter, Alexander T J; Hogben, Hannah J; Warren, John E; Pascu, Sofia I; Kay, Christopher W M; Timmel, Christiane R; Anderson, Harry L

    2009-09-30

    A series of butadiyne-linked zinc porphyrin oligomers, with one, two, three, and four porphyrin units and lengths of up to 75 A, have been spin-labeled at both ends with stable nitroxide TEMPO radicals. The pulsed EPR technique of double electron electron resonance (DEER) was used to probe the distribution of intramolecular end-to-end distances, under a range of conditions. DEER measurements were carried out at 50 K in two types of dilute solution glasses: deutero-toluene (with 10% deutero-pyridine) and deutero-o-terphenyl (with 5% 4-benzyl pyridine). The complexes of the porphyrin oligomers with monodentate ligands (pyridine or 4-benzyl pyridine) principally adopt linear conformations. Nonlinear conformations are less populated in the lower glass-transition temperature solvent. When the oligomers bind star-shaped multidentate ligands, they are forced to bend into nonlinear geometries, and the experimental end-to-end distances for these complexes match those from molecular mechanics calculations. Our results show that porphyrin-based molecular wires are shape-persistent, and yet that their shapes can deformed by binding to multivalent ligands. Self-assembled ladder-shaped 2:2 complexes were also investigated to illustrate the scope of DEER measurements for providing structural information on synthetic noncovalent nanostructures. PMID:19736940

  10. A Transiting Jupiter Analog

    CERN Document Server

    Kipping, David M; Henze, Chris; Teachey, Alex; Isaacson, Howard T; Petigura, Erik A; Marcy, Geoffrey W; Buchhave, Lars A; Chen, Jingjing; Bryson, Steve T; Sandford, Emily

    2016-01-01

    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of $(0.91\\pm0.02)$ $R_{\\mathrm{Jup}}$, a low orbital eccentricity ($0.06_{-0.04}^{+0.10}$) and an equilibrium temperature of $(131\\pm3)$ K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric ...

  11. TRANSPARENCY IN ELECTRONIC BUSINESS NEGOTIATIONS – EVIDENCE BASED ANALYSIS

    Directory of Open Access Journals (Sweden)

    Radoslav Delina

    2014-12-01

    Full Text Available Purpose: In current economy, where ICT plays a crucial role for being competitive and effective, businesses are facing higher pressures of flexibility and efficiency than ever before. Transparency is often considered as a suitable mechanism for better market prices and more efficient market environment. Electronic business environment provides the possibility to set up more transparent environment and bring higher competitiveness and efficiency on the market. The paper analyse the impact of transparency on prices in e-procurement.Methodology: Reverse auctions are considered as transparent tool simulating in partial level real competition. Together, it allows to examine several levels of transparency set up in auction negotiation process. The impact of transparency on final prices was analysed on real data using relation based analysis were different situations of transparency set up is compared against achieved final price.Findings: Research results based on real data shows, that generally, the transparency in electronic reverse auction can lead to more negative prices agreed by purchasers as current scientific and commercial promotions.Research limitation: Significance of research results is limited due to still low readiness and skills of e-procurers. The validation of results is needed to realized within longer period of time and from environments with different level of e-readiness. Together, it reveal that transparency is more complex issue where the significance of transparency can reveal its sense in some specific situations on the market and negotiation.Value of paper: Evidenced based research reveal some controversy results which support new scientific efforts in microeconomics and socio-economic impact of ICT fields. Together, it affects real practitioners in way how to use and perceive claimed impact of reverse auction solutions.

  12. Thin-bedded reservoir analogs in an ancient delta using terrestrial laser scanner and high-resolution ground-based hyperspectral cameras

    Science.gov (United States)

    Snyder, Casey J.; Khan, Shuhab D.; Bhattacharya, Janok P.; Glennie, Craig; Seepersad, Darsel

    2016-08-01

    Ground-based terrestrial laser scanning and hyperspectral sensors were used to image fine-scale heterogeneity in outcrops of prodeltaic heterolithic facies of Parasequence 6 of the Cretaceous Ferron Notom delta in Southern Utah. Previous work shows that Parasequence 6 is an upward coarsening fluvial-dominated, wave-influenced deltaic deposit containing heterolithic thin-bedded facies representing distal delta front and proximal prodelta environments. Primarily, the thin beds have been interpreted as turbidites, storm beds (tempestites), and hyperpycnites. These deposits represent analogs for thin-bedded unconventional pay zones that lie at the margins of conventional deltaic sandstone reservoirs. The terrestrial laser scanner was used to create a centimeter- to decimeter-scale, digital representation of the outcrops in three dimensions. Hyperspectral sensors record electromagnetic radiation reflected off the outcrops in 840 contiguous bands, which were then used to generate a spectral signature for each pixel sampled. The spectral signatures are a function of mineralogy, chemistry, surface alteration, grain-size, and cements, and were used to distinguish thin mudstones from sandstones within an interbedded succession at the base of a deltaic parasequence. Comparison between the spectral signatures recorded from the outcrop and those of reference materials, and with previous facies architecture studies, enables lithofacies to be identified and subsequently accurately mapped. Hyperspectral data are then draped over the terrestrial laser scanner model to generate a spatially-accurate detailed three-dimensional (3D) geologic map of the heterogeneity. Approximately 100 m of outcrop was imaged laterally with the hyperspectral camera and terrestrial laser scanner on the previously mapped distal delta front and prodeltaic facies of Parasequence 6. Bed thickness data, based on measurements made along depositional dip versus strike, show that bed geometries are anisotropic

  13. Concept of a laser-plasma based electron source for sub-10 fs electron diffraction

    CERN Document Server

    Faure, J; Beaurepaire, B; Gallé, G; Vernier, A; Lifschitz, A

    2015-01-01

    We propose a new concept of an electron source for ultrafast electron diffraction with sub-10~fs temporal resolution. Electrons are generated in a laser-plasma accelerator, able to deliver femtosecond electron bunches at 5 MeV energy with kHz repetition rate. The possibility of producing this electron source is demonstrated using Particle-In-Cell simulations. We then use particle tracking simulations to show that this electron beam can be transported and manipulated in a realistic beamline, in order to reach parameters suitable for electron diffraction. The beamline consists of realistic static magnetic optics and introduces no temporal jitter. We demonstrate numerically that electron bunches with 5~fs duration and containing 1.5~fC per bunch can be produced, with a transverse coherence length exceeding 2~nm, as required for electron diffraction.

  14. Synthesis of α,β-Unsaturated Carbonyl-Based Compounds, Oxime and Oxime Ether Analogs as Potential Anticancer Agents for Overcoming Cancer Multidrug Resistance by Modulation of Efflux Pumps in Tumor Cells.

    Science.gov (United States)

    Qin, Hua-Li; Leng, Jing; Zhang, Cheng-Pan; Jantan, Ibrahim; Amjad, Muhammad Wahab; Sher, Muhammad; Naeem-Ul-Hassan, Muhammad; Hussain, Muhammad Ajaz; Bukhari, Syed Nasir Abbas

    2016-04-14

    Sixty-nine novel α,β-unsaturated carbonyl based compounds, including cyclohexanone, tetralone, oxime, and oxime ether analogs, were synthesized. The antiproliferative activity determined by using seven different human cancer cell lines provided a structure-activity relationship. Compound 8ag exhibited high antiproliferative activity against Panc-1, PaCa-2, A-549, and PC-3 cell lines, with IC50 value of 0.02 μM, comparable to the positive control Erlotinib. The ten most active antiproliferative compounds were assessed for mechanistic effects on BRAF(V600E), EGFR TK kinases, and tubulin polymerization, and were investigated in vitro to reverse efflux-mediated resistance developed by cancer cells. Compound 8af exhibited the most potent BRAF(V600E) inhibitory activity with an IC50 value of 0.9 μM. Oxime analog 7o displayed the most potent EGFR TK inhibitory activity with an IC50 of 0.07 μM, which was analogous to the positive control. Some analogs including 7f, 8af, and 8ag showed a dual role as anticancer and MDR reversal agents. PMID:27010345

  15. Spiral structure in galaxies: analogies

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, R.C.

    1976-01-01

    The vortex analogy to galactic spiral structures is considered. Caution against carrying the analogy past its region of applicability is noted; and some experiments with vorticities are mentioned. (JFP)

  16. A putative RNA-interference-based immune system in prokaryotes: computational analysis of the predicted enzymatic machinery, functional analogies with eukaryotic RNAi, and hypothetical mechanisms of action

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2006-03-01

    Full Text Available Abstract Background All archaeal and many bacterial genomes contain Clustered Regularly Interspaced Short Palindrome Repeats (CRISPR and variable arrays of the CRISPR-associated (cas genes that have been previously implicated in a novel form of DNA repair on the basis of comparative analysis of their protein product sequences. However, the proximity of CRISPR and cas genes strongly suggests that they have related functions which is hard to reconcile with the repair hypothesis. Results The protein sequences of the numerous cas gene products were classified into ~25 distinct protein families; several new functional and structural predictions are described. Comparative-genomic analysis of CRISPR and cas genes leads to the hypothesis that the CRISPR-Cas system (CASS is a mechanism of defense against invading phages and plasmids that functions analogously to the eukaryotic RNA interference (RNAi systems. Specific functional analogies are drawn between several components of CASS and proteins involved in eukaryotic RNAi, including the double-stranded RNA-specific helicase-nuclease (dicer, the endonuclease cleaving target mRNAs (slicer, and the RNA-dependent RNA polymerase. However, none of the CASS components is orthologous to its apparent eukaryotic functional counterpart. It is proposed that unique inserts of CRISPR, some of which are homologous to fragments of bacteriophage and plasmid genes, function as prokaryotic siRNAs (psiRNA, by base-pairing with the target mRNAs and promoting their degradation or translation shutdown. Specific hypothetical schemes are developed for the functioning of the predicted prokaryotic siRNA system and for the formation of new CRISPR units with unique inserts encoding psiRNA conferring immunity to the respective newly encountered phages or plasmids. The unique inserts in CRISPR show virtually no similarity even between closely related bacterial strains which suggests their rapid turnover, on evolutionary scale

  17. An Electron Beam Profile Instrument Based on FBGs

    Directory of Open Access Journals (Sweden)

    Dan Sporea

    2014-08-01

    Full Text Available Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/energy distribution in the beam are parameters of interest for charged particle accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transverse profile of the beam, its position, its centroid location, and its focus or flatness depend on the instrument operating conditions or on the beam exit setup. Proof-of-concept of a new type of charged particle beam diagnostics based on fiber Bragg gratings (FBGs was demonstrated. Its operating principle relies on the measurement of the peak wavelength changes for an array of FBG sensors as function of the temperature following the exposure to an electron beam. Periodically, the sensor irradiation is stopped and the FBG are force cooled to a reference temperature with which the temperature influencing each sensor during beam exposure is compared. Commercially available FBGs, and FBGs written in radiation resistant optical fibers, were tested under electron beam irradiation in order to study their possible use in this application.

  18. Electronic structure of Zr-based metallic glasses

    International Nuclear Information System (INIS)

    The electronic structure and phase stability of the Zr66.7Ni33.3 and Zr66.7Cu33.3 metallic glasses has been investigated by the recursion calculations method using a giant atom-cluster, of which arrangements of constituent atoms were determined by the Reverse Monte Carlo experimental structural studies reported before [T. Fukunaga, K. Itoh, T. Otomo, K. Mori, M. Sugiyama, H. Kato, M. Hasegawa, A. Hirata, Y. Hirotsu, Intermetallics 14 (2006) 893]. The electronic structure of the former is similar to that of the relevant Zr2Ni compound, while that of the latter is completely different from that of the relevant Zr2Cu compound. We have also calculated the band energy of the characteristic clusters in these metallic glasses. The smaller and Zr-richer these clusters are, the lower the band energy at the center of the cluster tends to be. The stability of these characteristic clusters of both metallic glasses can be explained by the total band energy based on the calculated local density of states and is consistent with the reported experimental Volonoi analysis.

  19. Electron accommodation dynamics in the DNA base thymine

    International Nuclear Information System (INIS)

    The dynamics of electron attachment to the DNA base thymine are investigated using femtosecond time-resolved photoelectron imaging of the gas phase iodide-thymine (I−T) complex. An ultraviolet pump pulse ejects an electron from the iodide and prepares an iodine-thymine temporary negative ion that is photodetached with a near-IR probe pulse. The resulting photoelectrons are analyzed with velocity-map imaging. At excitation energies ranging from −120 meV to +90 meV with respect to the vertical detachment energy (VDE) of 4.05 eV for I−T, both the dipole-bound and valence-bound negative ions of thymine are observed. A slightly longer rise time for the valence-bound state than the dipole-bound state suggests that some of the dipole-bound anions convert to valence-bound species. No evidence is seen for a dipole-bound anion of thymine at higher excitation energies, in the range of 0.6 eV above the I−T VDE, which suggests that if the dipole-bound anion acts as a “doorway” to the valence-bound anion, it only does so at excitation energies near the VDE of the complex

  20. PROTEOTRONICS: The emerging science of protein-based electronic devices

    Science.gov (United States)

    Alfinito, Eleonora; Pousset, Jeremy; Reggiani, Lino

    2015-10-01

    Protein-mediated charge transport is of relevant importance in the design of protein based electronics and in attaining an adequate level of understanding of protein functioning. This is particularly true for the case of transmembrane proteins, like those pertaining to the G protein coupled receptors (GPCRs). These proteins are involved in a broad range of biological processes like catalysis, substance transport, etc., thus being the target of a large number of clinically used drugs. This paper briefly reviews a variety of experiments devoted to investigate charge transport in proteins and present a unified theoretical model able to relate macroscopic experimental results with the conformations of the amino acids backbone of the single protein.

  1. Computing environmental life of electronic products based on failure physics

    Institute of Scientific and Technical Information of China (English)

    Yongqiang Zhang; Zongchang Xu; Chunyang Hu

    2016-01-01

    In some situations, the accelerated life test on en-vironmental stress for electronic products is not easily imple-mented due to various restrictions, and thus engineers are lacking of data of the product life test. Concerning this prob-lem, environmental life of the printed circuit board (PCB) board is calculated by way of physics of failure. Influences of thermal cycle and vibration on PCB and its components are studied. Based on the analysis of force and stress between components and the PCB board in thermal cycle events and vibration events, four life computing models of pins and sol-dered dots are established. The miler damage ratio is used to calculate the accumulated damage of a pin or a soldered dot, and then the environment life of the PCB board can be de-termined by the first failed one. Finaly, an example is used to ilustrate the models and their calculations.

  2. Positron lifetime study in dilute electron irradiated lead based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moya, G. [Lab. de Physique des Materiaux, 13 Marseille (France); Li, X.H. [D.R.F.M., S.P.2.M., M.P., C.E.N.G., 38 Grenoble (France); Menai, A. [Lab. de Physique des Materiaux, 13 Marseille (France); Kherraz, M. [Lab. de Physique des Materiaux, 13 Marseille (France); Amenzou, H. [Lab. de Physique des Materiaux, 13 Marseille (France); Bernardini, J. [Lab. de Metallurgie, 13 Marseille (France); Moser, P. [D.R.F.M., S.P.2.M., M.P., C.E.N.G., 38 Grenoble (France)

    1995-06-01

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centred at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (orig.)

  3. Silicon-based metallic micro grid for electron field emission

    International Nuclear Information System (INIS)

    A micro-scale metal grid based on a silicon frame for application to electron field emission devices is introduced and experimentally demonstrated. A silicon lattice containing aperture holes with an area of 80 × 80 µm2 and a thickness of 10 µm is precisely manufactured by dry etching the silicon on one side of a double-polished silicon wafer and by wet etching the opposite side. Because a silicon lattice is more rigid than a pure metal lattice, a thin layer of Au/Ti deposited on the silicon lattice for voltage application can be more resistant to the geometric stress caused by the applied electric field. The micro-fabrication process, the images of the fabricated grid with 88% geometric transparency and the surface profile measurement after thermal feasibility testing up to 700 °C are presented. (paper)

  4. Positron lifetime study in dilute electron irradiated lead based alloys

    International Nuclear Information System (INIS)

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centred at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (orig.)

  5. LASER-BASED PROFILE MONITOR FOR ELECTRON BEAMS

    International Nuclear Information System (INIS)

    High performance TeV energy electron / positron colliders (LC) are the first machines to require online, non-invasive beam size monitors for micron and sub-micron for beam phase space optimization. Typical beam densities in the LC are well beyond the threshold density for single pulse melting and vaporization of any material, making conventional wire scanners ineffective. Using a finely focused, diffraction limited high power laser, it is possible to devise a sampling profile monitor that, in operation, resembles a wire scanner. Very high resolution laser-based profile monitors have been developed and tested, first at FFTB (SLAC) and later at SLC and ATF. The monitor has broad applicability and we review here the technology, application and status of ongoing research programs

  6. Positron lifetime study in dilute electron irradiated lead based alloys

    International Nuclear Information System (INIS)

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centered at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (authors). 3 figs., 9 refs

  7. A Novel Integrated SET Based Inverter for Nano Power Electronic Applications

    OpenAIRE

    Negin Moezi; Daryoosh Dideban; Abbas Ketabi

    2008-01-01

    In this research an emerging field of power electronics in nanotechnology is survived. This application-based technology today is called Nano Power Electronics. It utilizes nano electronic transistors in switching applications in the range of nano power for signal shaping purposes. In recent years Single Electron Transistors are highly interested in nano electronic applications. They have got inherently fast tunneling rate, which makes them highly suitable for high-speed operation. Based on t...

  8. Surfaces and interfaces in polymer-based electronics

    Science.gov (United States)

    Fahlman, M.; Salaneck, W. R.

    2002-03-01

    Research on electronics applications such as light-emitting devices for flat-panel displays, transistors, sensors and even solid state lasers based on conducting polymers is presently under way and in some cases has reached the stage of prototype production. The mechanisms for charge injection and conduction in these materials are being studied, as are the physics of luminescence and its quenching. Lately, research into controlling film morphology through self-organizing techniques also has gained interest. Though the present interest in conducting polymers mainly concerns the pristine semiconducting state, doped conducting polymers are also studied for potential use in many applications. In this paper, we present an overview of some of the central issues in surface and interface science in the field, as well as provide our view on what may lie ahead in the future. Specifically, the importance of metal/polymer, polymer/metal and polymer/polymer interfaces is addressed. We illustrate these using polymer-based light-emitting devices, though the same type of issues appear in other polymer-based applications such as transistors and solar cells.

  9. Analogy perception applied to seven tests of word comprehension

    CERN Document Server

    Turney, Peter D

    2011-01-01

    It has been argued that analogy is the core of cognition. In AI research, algorithms for analogy are often limited by the need for hand-coded high-level representations as input. An alternative approach is to use high-level perception, in which high-level representations are automatically generated from raw data. Analogy perception is the process of recognizing analogies using high-level perception. We present PairClass, an algorithm for analogy perception that recognizes lexical proportional analogies using representations that are automatically generated from a large corpus of raw textual data. A proportional analogy is an analogy of the form A:B::C:D, meaning "A is to B as C is to D". A lexical proportional analogy is a proportional analogy with words, such as carpenter:wood::mason:stone. PairClass represents the semantic relations between two words using a high-dimensional feature vector, in which the elements are based on frequencies of patterns in the corpus. PairClass recognizes analogies by applying s...

  10. Electron and hole Hong-Ou-Mandel interferometry

    OpenAIRE

    Jonckheere, T.; Rech, J.; Wahl, C.; Martin, T

    2012-01-01

    We consider the electronic analog of the quantum optics Hong-Ou-Mandel interferometer, in a realistic condensed matter device based on single electron emission in chiral edge states. For electron-electron collisions, we show that the measurement of the zero-frequency current correlations at the output of a quantum point contact produces a dip giving precious information on the electronic wavepackets and coherence. As a feature truly unique to Fermi statistics and condensed matter, we show tha...

  11. Sustained First Remission in an Adolescent With Hepatosplenic T-Cell Lymphoma Treated With T-Cell Leukemia Induction, Nucleoside Analog-Based Consolidation, and Early Hematopoietic Stem Cell Transplant

    OpenAIRE

    Schafer, Eric; Chen, Allen; Arceci, Robert J.

    2009-01-01

    Hepatosplenic T-cell lymphoma (HTCL) is a rare malignancy. Prognosis is poor with only a few case reports of long-term survivors. While HTCL universally involves the bone marrow, the condition has been most often treated with multimodal lymphoma specific chemotherapy. We report a durable, sustained first remission in an adolescent treated for HTCL who received induction therapy according to a high risk T-cell leukemia regimen, a nucleoside analog-based consolidation, and allogeneic transplant...

  12. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  13. Highly sensitive hot electron bolometer based on disordered graphene

    OpenAIRE

    Qi Han; Teng Gao; Rui Zhang; Yi Chen; Jianhui Chen; Gerui Liu; Yanfeng Zhang; Zhongfan Liu; Xiaosong Wu; Dapeng Yu

    2013-01-01

    A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using ...

  14. Space flight nutrition research: platforms and analogs

    Science.gov (United States)

    Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.

    2002-01-01

    Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

  15. Development of an Electronic Claim System Based on an Integrated Electronic Health Record Platform to Guarantee Interoperability

    OpenAIRE

    Kim, Hwa Sun; Cho, Hune; Lee, In Keun

    2011-01-01

    Objectives We design and develop an electronic claim system based on an integrated electronic health record (EHR) platform. This system is designed to be used for ambulatory care by office-based physicians in the United States. This is achieved by integrating various medical standard technologies for interoperability between heterogeneous information systems. Methods The developed system serves as a simple clinical data repository, it automatically fills out the Centers for Medicare and Medic...

  16. Discrete Calculus by Analogy

    CERN Document Server

    Izadi, F A; Bagirov, G

    2009-01-01

    With its origins stretching back several centuries, discrete calculus is now an increasingly central methodology for many problems related to discrete systems and algorithms. The topics covered here usually arise in many branches of science and technology, especially in discrete mathematics, numerical analysis, statistics and probability theory as well as in electrical engineering, but our viewpoint here is that these topics belong to a much more general realm of mathematics; namely calculus and differential equations because of the remarkable analogy of the subject to this branch of mathemati

  17. A Novel Diagnostics of Ultrashort Electron Bunches Based on Detection of Coherent Radiation from Bunched Electron Beam in an Undulator

    CERN Document Server

    Saldin, Evgeny L; Yurkov, Mikhail V

    2004-01-01

    We propose a new method for measurements of the longitudinal profile of 100 femtosecond electron bunches for X-ray Free Electron Lasers (XFELs). The method is based on detection of coherent undulator radiation produced by modulated electron beam. Seed optical quantum laser is used to produce exact optical replica of ultrashort electron bunches. The replica is generated in apparatus which consists of an input undulator (energy modulator), and output undulator (radiator) separated by a dispersion section. The radiation in the output undulator is excited by the electron bunch modulated at the optical wavelength and rapidly reaches a hundred-MW-level power. We then use the now-standard method of ultrashort laser pulse-shape measurement, a tandem combination of autocorrelator and spectrum (FROG -- frequency resolved optical gating) providing real-time single-shot measurements of the electron bunch structure. The big advantage of proposed technique is that it can be used to determine the slice energy spread and emi...

  18. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Directory of Open Access Journals (Sweden)

    Jia-Jia Zheng

    2016-01-01

    Full Text Available Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn. Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  19. An approved personal dosimetry service based on an electronic dosimeter

    International Nuclear Information System (INIS)

    At the Second Conference on Radiation Protection and Dosimetry a paper was presented which, in part, announced the development of an electronic dosimeter to be undertaken in the UK by the National Radiological Protection Board (NRPB) and Siemens Plessey Controls Ltd. This dosimeter was to be of a standard suitable for use as the basis of an approved personal dosimetry service for photon and beta radiations. The project has progressed extremely well and dosimeters and readers are about to become commercially available. The system and the specification of the dosimeter are presented. The NRPB is in the process of applying for approval by the Health and Safety Executive (HSE) to operate as personal monitoring service based on this dosimeter. As part of the approval procedure the dosimeter is being type tested and is also undergoing an HSE performance test and wearer trials. The tests and the wearer trials are described and a summary of the results to date presented. The way in which the service will be organized and operated is described and a comparison is made between the running of the service and others based on passive dosimeters at NRPB

  20. Magnetic and electronic properties of porphyrin-based molecular nanowires

    International Nuclear Information System (INIS)

    Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn). Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics

  1. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jia-Jia; Li, Qiao-Zhi; Dang, Jing-Shuang; Zhao, Xiang, E-mail: xzhao@mail.xjtu.edu.cn [Institute for Chemical Physics & Department of Chemistry, MOE Key Laboratory for Non-equilibrium Condensed Matter and Quantum Engineering, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Wei-Wei [Research Center for Computational Science, Institute for Molecular Science, Okazaki, Aichi 444-8585 (Japan)

    2016-01-15

    Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn). Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  2. Approaches to synthetic platelet analogs.

    Science.gov (United States)

    Modery-Pawlowski, Christa L; Tian, Lewis L; Pan, Victor; McCrae, Keith R; Mitragotri, Samir; Sen Gupta, Anirban

    2013-01-01

    Platelet transfusion is routinely used for treating bleeding complications in patients with hematologic or oncologic clotting disorders, chemo/radiotherapy-induced myelosuppression, trauma and surgery. Currently, these transfusions mostly use allogeneic platelet concentrates, while products like lyophilized platelets, cold-stored platelets and infusible platelet membranes are under investigation. These natural platelet-based products pose considerable risks of contamination, resulting in short shelf-life (3-5 days). Recent advances in pathogen reduction technologies have increased shelf-life to ~7 days. Furthermore, natural platelets are short in supply and also cause several biological side effects. Hence, there is significant clinical interest in platelet-mimetic synthetic analogs that can allow long storage-life and minimum side effects. Accordingly, several designs have been studied which decorate synthetic particles with motifs that promote platelet-mimetic adhesion or aggregation. Recent refinement in this design involves combining the adhesion and aggregation functionalities on a single particle platform. Further refinement is being focused on constructing particles that also mimic natural platelet's shape, size and elasticity, to influence margination and wall-interaction. The optimum design of a synthetic platelet analog would require efficient integration of platelet's physico-mechanical properties and biological functionalities. We present a comprehensive review of these approaches and provide our opinion regarding the future directions of this research. PMID:23092864

  3. Analog forecasting with dynamics-adapted kernels

    Science.gov (United States)

    Zhao, Zhizhen; Giannakis, Dimitrios

    2016-09-01

    Analog forecasting is a nonparametric technique introduced by Lorenz in 1969 which predicts the evolution of states of a dynamical system (or observables defined on the states) by following the evolution of the sample in a historical record of observations which most closely resembles the current initial data. Here, we introduce a suite of forecasting methods which improve traditional analog forecasting by combining ideas from kernel methods developed in harmonic analysis and machine learning and state-space reconstruction for dynamical systems. A key ingredient of our approach is to replace single-analog forecasting with weighted ensembles of analogs constructed using local similarity kernels. The kernels used here employ a number of dynamics-dependent features designed to improve forecast skill, including Takens’ delay-coordinate maps (to recover information in the initial data lost through partial observations) and a directional dependence on the dynamical vector field generating the data. Mathematically, our approach is closely related to kernel methods for out-of-sample extension of functions, and we discuss alternative strategies based on the Nyström method and the multiscale Laplacian pyramids technique. We illustrate these techniques in applications to forecasting in a low-order deterministic model for atmospheric dynamics with chaotic metastability, and interannual-scale forecasting in the North Pacific sector of a comprehensive climate model. We find that forecasts based on kernel-weighted ensembles have significantly higher skill than the conventional approach following a single analog.

  4. 23rd workshop on Advances in Analog Circuit Design

    CERN Document Server

    Baschirotto, Andrea; Makinwa, Kofi

    2015-01-01

    This book is based on the 18 tutorials presented during the 23rd workshop on Advances in Analog Circuit Design.  Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, serving as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.    • Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing; • Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; • Presents material in a tutorial-based format.

  5. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate) (PMEA) Analogous Polymers for Attachment-Based Cell Enrichment

    OpenAIRE

    Hoshiba, Takashi; Nemoto, Eri; Sato, Kazuhiro; Orui, Toshihiko; Otaki, Takayuki; Yoshihiro, Ayano; Tanaka, Masaru

    2015-01-01

    Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investiga...

  6. ESPRESSO instrument control electronics: a PLC based distributed layout for a second generation instrument at ESO VLT

    Science.gov (United States)

    Baldini, V.; Cirami, R.; Coretti, I.; Cristiani, S.; Di Marcantonio, P.; Mannetta, M.; Santin, P.; Mégevand, D.; Zerbi, F.

    2014-07-01

    ESPRESSO is an ultra-stable fiber-fed spectrograph designed to combine incoherently the light coming from up to 4 Unit Telescopes of the ESO VLT. From the Nasmyth focus of each telescope the light, through an optical path, is fed by the Coudé Train subsystems to the Front End Unit placed in the Combined Coudé Laboratory. The Front End is composed by one arm for each telescope and its task is to convey the incoming light, after a calibration process, into the spectrograph fibers. To perform these operations a large number of functions are foreseen, like motorized stages, lamps, digital and analog sensors that, coupled with dedicated Technical CCDs (two per arms), allow to stabilize the incoming beam up to the level needed to exploit the ESPRESSO scientific requirements. The Instrument Control Electronics goal is to properly control all the functions in the Combined Coudé Laboratory and the spectrograph itself. It is fully based on a distributed PLC architecture, abandoning in this way the VME-based technology previously adopted for the ESO VLT instruments. In this paper we will describe the ESPRESSO Instrument Control Electronics architecture, focusing on the distributed layout and its interfaces with the other ESPRESSO subsystems.

  7. Graphene Electronic Device Based Biosensors and Chemical Sensors

    Science.gov (United States)

    Jiang, Shan

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first part of my thesis, I demonstrated the fabrication of graphene nanomesh (GNM), which is a graphene thin film with a periodic array of holes punctuated in it. The periodic holes introduce long periphery active edges that provide a high density of functional groups (e.g. carboxylic groups) to allow for covalent grafting of specific receptor molecules for chemical and biosensor applications. After covalently functionalizing the GNM with glucose oxidase, I managed to make a novel electronic sensor which can detect glucose as well as pH change. In the following part of my thesis I demonstrate the fabrication of graphene-hemin conjugate for nitric oxide detection. The non-covalent functionalization through pi-pi stacking interaction allows reliable immobilization of hemin molecules on graphene without damaging the graphene lattice to ensure the highly sensitive and specific detection of nitric oxide. The graphene-hemin nitric oxide sensor is capable of real-time monitoring of nitric oxide concentrations, which is of central importance for probing the diverse roles of nitric oxide in neurotransmission, cardiovascular systems, and immune responses. Our studies demonstrate that the graphene-hemin sensors can respond rapidly to nitric oxide in physiological environments with sub-nanomolar sensitivity. Furthermore, in vitro studies show that the graphene-hemin sensors can be used for the detection of nitric oxide released from macrophage cells and endothelial cells, demonstrating their

  8. Analog circuit design a tutorial guide to applications and solutions

    CERN Document Server

    Williams, Jim

    2011-01-01

    * Covers the fundamentals of linear/analog circuit and system design to guide engineers with their design challenges. * Based on the Application Notes of Linear Technology, the foremost designer of high performance analog products, readers will gain practical insights into design techniques and practice. * Broad range of topics, including power management tutorials, switching regulator design, linear regulator design, data conversion, signal conditioning, and high frequency/RF design. * Contributors include the leading lights in analog design, Robert Dobkin, Jim Willia

  9. Controlled Phase Gate Based on an Electron Floating on Helium

    Institute of Scientific and Technical Information of China (English)

    SHI Yan-Li; MEI Feng; YU Ya-Fei; ZHANG Zhi-Ming

    2011-01-01

    We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium. The electron is also driven by a classical laser beam and by an oscillating magnetic field. In the process, the vibration of the electron is used as the qubus to couple the energy level qubit (1D Stark-shifted hydrogen) and spin qubit Ultimately. the controlled phase gate can be generated.%@@ We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium.The electron is also driven by a classical laser beam and by an oscillating magnetic field.In the process,the vibration of the electron is used as the qubus to couple the energy level qubit(1D Stark-shifted hydrogen) and spin qubit.Ultimately,the controlled phase gate can be generated.

  10. Obstacles of XML-based electronic accounting reference

    OpenAIRE

    Juhava, Antti

    2012-01-01

    Research objectives The use of electronic accounting reference in its newest form, constructed from the viewpoint of unified practices, seems to have fallen short. Because no proper research has been conducted to depict the reasons that effect on the adoption of electronic accounting reference, this thesis aims to find answers through the following research question: What reasons hinder the adoption of electronic accounting reference for incoming invoices in Finnish companies? Researc...

  11. Sculpturing the Electron Wave Function

    CERN Document Server

    Shiloh, Roy; Lilach, Yigal; Arie, Ady

    2014-01-01

    Coherent electrons such as those in electron microscopes, exhibit wave phenomena and may be described by the paraxial wave equation. In analogy to light-waves, governed by the same equation, these electrons share many of the fundamental traits and dynamics of photons. Today, spatial manipulation of electron beams is achieved mainly using electrostatic and magnetic fields. Other demonstrations include simple phase-plates and holographic masks based on binary diffraction gratings. Altering the spatial profile of the beam may be proven useful in many fields incorporating phase microscopy, electron holography, and electron-matter interactions. These methods, however, are fundamentally limited due to energy distribution to undesired diffraction orders as well as by their binary construction. Here we present a new method in electron-optics for arbitrarily shaping of electron beams, by precisely controlling an engineered pattern of thicknesses on a thin-membrane, thereby molding the spatial phase of the electron wav...

  12. Characterization and Modeling of Nonfilamentary Ta/TaOx/TiO2/Ti Analog Synaptic Device

    Science.gov (United States)

    Wang, Yu-Fen; Lin, Yen-Chuan; Wang, I.-Ting; Lin, Tzu-Ping; Hou, Tuo-Hung

    2015-05-01

    A two-terminal analog synaptic device that precisely emulates biological synaptic features is expected to be a critical component for future hardware-based neuromorphic computing. Typical synaptic devices based on filamentary resistive switching face severe limitations on the implementation of concurrent inhibitory and excitatory synapses with low conductance and state fluctuation. For overcoming these limitations, we propose a Ta/TaOx/TiO2/Ti device with superior analog synaptic features. A physical simulation based on the homogeneous (nonfilamentary) barrier modulation induced by oxygen ion migration accurately reproduces various DC and AC evolutions of synaptic states, including the spike-timing-dependent plasticity and paired-pulse facilitation. Furthermore, a physics-based compact model for facilitating circuit-level design is proposed on the basis of the general definition of memristor devices. This comprehensive experimental and theoretical study of the promising electronic synapse can facilitate realizing large-scale neuromorphic systems.

  13. A nanotube based electron microbeam cellular irradiator for radiobiology research

    Science.gov (United States)

    Bordelon, David E.; Zhang, Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Zhou, Otto Z.; Chang, Sha

    2008-12-01

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 μm has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development.

  14. A nanotube based electron microbeam cellular irradiator for radiobiology research

    International Nuclear Information System (INIS)

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 μm has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development.

  15. Electronic structure of Fe- vs. Ru-based dye molecules

    International Nuclear Information System (INIS)

    In order to explore whether Ru can be replaced by inexpensive Fe in dye molecules for solar cells, the differences in the electronic structure of Fe- and Ru-based dyes are investigated by X-ray absorption spectroscopy and first-principles calculations. Molecules with the metal in a sixfold, octahedral N cage, such as tris(bipyridines) and tris(phenanthrolines), exhibit a systematic downward shift of the N 1s-to-π* transition when Ru is replaced by Fe. This shift is explained by an extra transfer of negative charge from the metal to the N ligands in the case of Fe, which reduces the binding energy of the N 1s core level. The C 1s-to-π* transitions show the opposite trend, with an increase in the transition energy when replacing Ru by Fe. Molecules with the metal in a fourfold, planar N cage (porphyrins) exhibit a more complex behavior due to a subtle competition between the crystal field, axial ligands, and the 2+ vs. 3+ oxidation states.

  16. Digital waterway construction based on inland electronic navigation chart

    Science.gov (United States)

    Wang, Xue; Pan, Junfeng; Zhu, Weiwei

    2015-12-01

    With advantages of large capacity, long distance, low energy consumption, low cost, less land occupation and light pollution, inland waterway transportation becomes one of the most important constituents of the comprehensive transportation system and comprehensive water resources utilization in China. As one of "three elements" of navigation, waterway is the important basis for the development of water transportation and plays a key supporting role in shipping economic. The paper discuss how to realize the informatization and digitization of waterway management based on constructing an integrated system of standard inland electronic navigation chart production, waterway maintenance, navigation mark remote sensing and control, ship dynamic management, and water level remote sensing and report, which can also be the foundation of the intelligent waterway construction. Digital waterway construction is an information project and also has a practical meaning for waterway. It can not only meet the growing high assurance and security requirements for waterway, but also play a significant advantage in improving transport efficiency, reducing costs, promoting energy conservation and so on. This study lays a solid foundation on realizing intelligent waterway and building a smooth, efficient, safe, green modern inland waterway system, and must be considered as an unavoidable problem for the coordinated development between "low carbon" transportation and social economic.

  17. Electronic structure of Fe- vs. Ru-based dye molecules

    DEFF Research Database (Denmark)

    Johnson, Phillip S.; Cook, Peter L.; Zegkinoglou, Ioannis;

    2013-01-01

    In order to explore whether Ru can be replaced by inexpensive Fe in dye molecules for solar cells, the differences in the electronic structure of Fe- and Ru-based dyes are investigated by X-ray absorption spectroscopy and first-principles calculations. Molecules with the metal in a sixfold......, octahedral N cage, such as tris(bipyridines) and tris(phenanthrolines), exhibit a systematic downward shift of the N 1s-to-π* transition when Ru is replaced by Fe. This shift is explained by an extra transfer of negative charge from the metal to the N ligands in the case of Fe, which reduces the binding...... energy of the N 1s core level. The C 1s-to-π* transitions show the opposite trend, with an increase in the transition energy when replacing Ru by Fe. Molecules with the metal in a fourfold, planar N cage (porphyrins) exhibit a more complex behavior due to a subtle competition between the crystal field...

  18. Inter-base Electronic Coupling for transport through DNA

    CERN Document Server

    Anantram, H M M P

    2005-01-01

    We develop a new approach to derive single state tight binding (SSTB) model for electron transport in the vicinity of valence-conduction bands of poly(G)-poly(C) and poly(A)-poly(T) DNA. The SSTB parameters are derived from {\\it first principles} and are used to model charge transport through finite length DNA. We investigate the rigor of reducing the full DNA Hamiltonian to SSTB model to represent charge transport in the vicinity of valence-conduction band. While the transmission coefficient spectrum is preserved, its position shifts in energy. Thymine is poorly represented and its peak height is substantially reduced. This is attributed to the abstraction of the HOMO-LUMO coupling to other eigen-states in the nearest neighbor DNA bases, and can be corrected within $2^{nd}$ order time independent perturbation theory. Inter-strand charge transport has also been analyzed and it is found that hopping to the nearest neighbor in the complementary strand is the most important process except in the valence band of ...

  19. Optical sensor array platform based on polymer electronic devices

    Science.gov (United States)

    Koetse, Marc M.; Rensing, Peter A.; Sharpe, Ruben B. A.; van Heck, Gert T.; Allard, Bart A. M.; Meulendijks, Nicole N. M. M.; Kruijt, Peter G. M.; Tijdink, Marcel W. W. J.; De Zwart, René M.; Houben, René J.; Enting, Erik; van Veen, Sjaak J. J. F.; Schoo, Herman F. M.

    2007-10-01

    Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

  20. Ferromagnetic-Insulator-Based Superconducting Junctions as Sensitive Electron Thermometers

    Science.gov (United States)

    Giazotto, F.; Solinas, P.; Braggio, A.; Bergeret, F. S.

    2015-10-01

    We present an exhaustive theoretical analysis of charge and thermoelectric transport in a normal-metal-ferromagnetic-insulator-superconductor junction and explore the possibility of its use as a sensitive thermometer. We investigate the transfer functions and the intrinsic noise performance for different measurement configurations. A common feature of all configurations is that the best temperature-noise performance is obtained in the nonlinear temperature regime for a structure based on an Europium chalcogenide ferromagnetic insulator in contact with a superconducting Al film structure. For an open-circuit configuration, although the maximal intrinsic temperature sensitivity can achieve 10 nK Hz-1 /2 , a realistic amplifying chain will reduce the sensitivity up to 10 μ K Hz-1 /2 . To overcome this limitation, we propose a measurement scheme in a closed-circuit configuration based on state-of-the-art superconducting-quantum-interference-device detection technology in an inductive setup. In such a case, we show that temperature-noise can be as low as 35 nK Hz-1 /2 . We also discuss a temperature-to-frequency converter where the obtained thermovoltage developed over a Josephson junction operated in the dissipative regime is converted into a high-frequency signal. We predict that the structure can generate frequencies up to approximately 120 GHz and transfer functions up to 200 GHz /K at around 1 K. If operated as an electron thermometer, the device may provide temperature-noise lower than 35 nK Hz-1 /2 thereby being potentially attractive for radiation-sensing applications.

  1. Vorticity in analog gravity

    Science.gov (United States)

    Cropp, Bethan; Liberati, Stefano; Turcati, Rodrigo

    2016-06-01

    In the analog gravity framework, the acoustic disturbances in a moving fluid can be described by an equation of motion identical to a relativistic scalar massless field propagating in curved space-time. This description is possible only when the fluid under consideration is barotropic, inviscid, and irrotational. In this case, the propagation of the perturbations is governed by an acoustic metric that depends algebrically on the local speed of sound, density, and the background flow velocity, the latter assumed to be vorticity-free. In this work we provide a straightforward extension in order to go beyond the irrotational constraint. Using a charged—relativistic and nonrelativistic—Bose–Einstein condensate as a physical system, we show that in the low-momentum limit and performing the eikonal approximation we can derive a d’Alembertian equation of motion for the charged phonons where the emergent acoustic metric depends on flow velocity in the presence of vorticity.

  2. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  3. An Analysis of Electronic Products’ Advertisements Based onthe Cooperative Principles

    Institute of Scientific and Technical Information of China (English)

    周亚林

    2015-01-01

    In moderntimes,more and more electronic products appear.Advertisements as an important way to promotethe products are applied by more and more businessmen.Many advertisements violate the Cooperative Principles which is proposed by the philosopher Paul Grice.This paper attempts to analyze the violations of cooperative principles in English electronic products’ advertisements.

  4. Analog pipeline readout for ATLAS calorimetry

    International Nuclear Information System (INIS)

    This paper presents the design and prototype testing of an analog pipeline readout module suitable for readout of the LAr calorimetry at the large hadron collider. The design has been driven by the readout requirements of the ATLAS electromagnetic liquid argon calorimeter and the ATLAS trigger design parameters. The results indicate that an analog pipeline readout system meeting the ATLAS requirements can be built using our modules. The SCA-chip employed has resolution approaching 13-bits (using the full range of the SCA) and can achieve a 16-bit dynamic range using a dual-range scheme. The module is based on switched capacitor array chips. A brief description of the design of the pipeline controller development, that will enable the SCA readout system to run as a deadtimeless analog RAM, is also given. (orig.)

  5. Plasma analog of particle-pair production

    International Nuclear Information System (INIS)

    It is shown that the plasma axial shear flow instability satisfies the Klein-Gordon equation. The plasma instability is then shown to be analogous to spontaneous particle-pair production when a potential energy is present that is greater than twice the particle rest mass energy. Stability criteria can be inferred based on field theoretical conservation laws. (UK)

  6. Electrons

    International Nuclear Information System (INIS)

    Fast electrons are used to produce isotopes for studying the cooper metabolism: Cu-64 in a cyclotron and Cu-67 in a linear accelerator. Localized electrons are responsible for the chemical and physiological characteristics of the trace elements. Studied are I, Cu, Co, Zn, Mo, Mn, Fe, Se, Mg. The Cu/Mo and Cu/Zn interactions are investigated. The levels of molybdenum, sulfate and zinc in the food are analysed. The role of the electrons in free radicals is discussed. The protection action of peroxidases and super oxidases against electron dangerous effect on normal physiology is also considered. Calculation of radiation damage and radiation protection is made. (author)

  7. UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC

    International Nuclear Information System (INIS)

    We discuss the design and current status of experiments to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By using an insertion device such as an undulator and observing changes in the spontaneous emission spectrum, the electron beam energy spread and emittance can be measured with high precision. The initial experiments will use spontaneous emission from 1.5 m of undulator. Later experiments will use up to 5 m of undulator with a goal of a high gain, XUV FEL.

  8. Analog and digital signal processing

    Science.gov (United States)

    Baher, H.

    The techniques of signal processing in both the analog and digital domains are addressed in a fashion suitable for undergraduate courses in modern electrical engineering. The topics considered include: spectral analysis of continuous and discrete signals, analysis of continuous and discrete systems and networks using transform methods, design of analog and digital filters, digitization of analog signals, power spectrum estimation of stochastic signals, FFT algorithms, finite word-length effects in digital signal processes, linear estimation, and adaptive filtering.

  9. Graphene-Based Chemical Vapor Sensors for Electronic Nose Applications

    Science.gov (United States)

    Nallon, Eric C.

    An electronic nose (e-nose) is a biologically inspired device designed to mimic the operation of the olfactory system. The e-nose utilizes a chemical sensor array consisting of broadly responsive vapor sensors, whose combined response produces a unique pattern for a given compound or mixture. The sensor array is inspired by the biological function of the receptor neurons found in the human olfactory system, which are inherently cross-reactive and respond to many different compounds. The use of an e-nose is an attractive approach to predict unknown odors and is used in many fields for quantitative and qualitative analysis. If properly designed, an e-nose has the potential to adapt to new odors it was not originally designed for through laboratory training and algorithm updates. This would eliminate the lengthy and costly R&D costs associated with materiel and product development. Although e-nose technology has been around for over two decades, much research is still being undertaken in order to find new and more diverse types of sensors. Graphene is a single-layer, 2D material comprised of carbon atoms arranged in a hexagonal lattice, with extraordinary electrical, mechanical, thermal and optical properties due to its 2D, sp2-bonded structure. Graphene has much potential as a chemical sensing material due to its 2D structure, which provides a surface entirely exposed to its surrounding environment. In this configuration, every carbon atom in graphene is a surface atom, providing the greatest possible surface area per unit volume, so that electron transport is highly sensitive to adsorbed molecular species. Graphene has gained much attention since its discovery in 2004, but has not been realized in many commercial electronics. It has the potential to be a revolutionary material for use in chemical sensors due to its excellent conductivity, large surface area, low noise, and versatile surface for functionalization. In this work, graphene is incorporated into a

  10. Practical approach to programmable analog circuits with memristors

    CERN Document Server

    Pershin, Yuriy V

    2009-01-01

    We suggest an approach to use memristors (resistors with memory) in programmable analog circuits. Our idea consists in a circuit design in which low voltages are applied to memristors during their operation as analog circuit elements and high voltages are used to program the memristor's states. This way, as it was demonstrated in recent experiments, the state of memristors does not essentially change during analog mode operation. As an example of our approach, we have built several programmable analog circuits demonstrating memristor-based programming of threshold, gain and frequency.

  11. ANUSANSKAR: a 16 channel frontend electronics (FEE) ASIC targeted for silicon pixel array detector based prototype Alice FOCAL

    International Nuclear Information System (INIS)

    ANUSANSKAR is a 16 channel pulse processing ASIC with analog multiplexed output designed in 0.7 um standard CMOS technology with each channel consisting of CSA, Semi Gaussian pulse shaper, DC cancellation and pedestal control, track and hold, output buffer blocks. The ASIC's analog multiplexed output can be read serially in daisy-chain topology. Testing, characterization and validation of ANUSANSKAR ASIC as readout for prototype ALICE forward calorimeter (FOCAL) has been carried out in PS beam line at CERN with up to 6 GeV of pion and electron beam. This paper describes the ANUSANSKAR ASIC along with the experimental results. (author)

  12. Electronic structure of nitride-based quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Winkelnkemper, Momme

    2008-11-07

    In the present work the electronic and optical properties of In{sub x}Ga{sub 1-x}N/GaN and GaN/AlN QDs are studied by means of eight-band k.p theory. Experimental results are interpreted in detail using the theoretical results. The k.p model for the QD electronicstructure calculations accounts for strain, piezo- and pyroelectric effects, spin-orbit and crystal-field splitting, and is implemented for arbitrarily shaped QDs on a finite differences grid. Few-particle corrections are included using the self-consistent Hartree method. Band parameters for the wurtzite and zinc-blende phases of GaN, AlN, and InN are derived from first-principle G{sub 0}W{sub 0} band-structure calculations. Reliable values are also provided for parameters that have not been determined experimentally yet. The electronic properties of nitride QDs are dominated by the large built-in piezo- and pyroelectric fields, which lead to a pronounced red-shift of excitonic transition energies and extremely long radiative lifetimes in large GaN/AlN QDs. In In{sub x}Ga{sub 1-x}N/GaN QDs these fields induce a pronounced dependence of the radiative excitonic lifetimes on the exact QD shape and composition. It is demonstrated that the resulting variations of the radiative lifetimes in an inhomogeneous QD ensemble are the origin of the multi-exponential luminescence decay frequently observed in time-resolved ensemble measurements on In{sub x}Ga{sub 1-x}N/GaN QDs. A polarization mechanism in nitride QDs based on strain-induced valence-band mixing effects is discovered. Due to the valence-band structure of wurtzite group-III nitrides and the specific strain situation in c-plane QDs, the confined hole states are formed predominantly by the two highest valence bands. In particular, the hole ground state (h{sub 0} {identical_to} h{sub A}) is formed by the A band, and the first excited hole state (h{sub 1} {identical_to} h{sub B}) by the B band. It is shown that the interband transitions involving h{sub A} or h

  13. Electronic structure of nitride-based quantum dots

    International Nuclear Information System (INIS)

    In the present work the electronic and optical properties of InxGa1-xN/GaN and GaN/AlN QDs are studied by means of eight-band k.p theory. Experimental results are interpreted in detail using the theoretical results. The k.p model for the QD electronicstructure calculations accounts for strain, piezo- and pyroelectric effects, spin-orbit and crystal-field splitting, and is implemented for arbitrarily shaped QDs on a finite differences grid. Few-particle corrections are included using the self-consistent Hartree method. Band parameters for the wurtzite and zinc-blende phases of GaN, AlN, and InN are derived from first-principle G0W0 band-structure calculations. Reliable values are also provided for parameters that have not been determined experimentally yet. The electronic properties of nitride QDs are dominated by the large built-in piezo- and pyroelectric fields, which lead to a pronounced red-shift of excitonic transition energies and extremely long radiative lifetimes in large GaN/AlN QDs. In InxGa1-xN/GaN QDs these fields induce a pronounced dependence of the radiative excitonic lifetimes on the exact QD shape and composition. It is demonstrated that the resulting variations of the radiative lifetimes in an inhomogeneous QD ensemble are the origin of the multi-exponential luminescence decay frequently observed in time-resolved ensemble measurements on InxGa1-xN/GaN QDs. A polarization mechanism in nitride QDs based on strain-induced valence-band mixing effects is discovered. Due to the valence-band structure of wurtzite group-III nitrides and the specific strain situation in c-plane QDs, the confined hole states are formed predominantly by the two highest valence bands. In particular, the hole ground state (h0 ≡ hA) is formed by the A band, and the first excited hole state (h1 ≡ hB) by the B band. It is shown that the interband transitions involving hA or hB are affected differently by an anisotropic strain field in the basal plane: hA transitions are

  14. Free-electron-laser-based biophysical and biomedical instrumentation

    International Nuclear Information System (INIS)

    A survey of biophysical and biomedical applications of free-electron lasers (FELs) is presented. FELs are pulsed light sources, collectively operating from the microwave through the x-ray range. This accelerator-based technology spans gaps in wavelength, pulse structure, and optical power left by conventional sources. FELs are continuously tunable and can produce high-average and high-peak power. Collectively, FEL pulses range from quasicontinuous to subpicosecond, in some cases with complex superpulse structures. Any given FEL, however, has a more restricted set of operational parameters. FELs with high-peak and high-average power are enabling biophysical and biomedical investigations of infrared tissue ablation. A midinfrared FEL has been upgraded to meet the standards of a medical laser and is serving as a surgical tool in ophthalmology and human neurosurgery. The ultrashort pulses produced by infrared or ultraviolet FELs are useful for biophysical investigations, both one-color time-resolved spectroscopy and when coupled with other light sources, for two-color time-resolved spectroscopy. FELs are being used to drive soft ionization processes in mass spectrometry. Certain FELs have high repetition rates that are beneficial for some biophysical and biomedical applications, but confound research for other applications. Infrared FELs have been used as sources for inverse Compton scattering to produce a pulsed, tunable, monochromatic x-ray source for medical imaging and structural biology. FEL research and FEL applications research have allowed the specification of spin-off technologies. On the horizon is the next generation of FELs, which is aimed at producing ultrashort, tunable x rays by self-amplified spontaneous emission with potential applications in biology

  15. A Cherenkov camera with integrated electronics based on the 'Smart Pixel' concept

    International Nuclear Information System (INIS)

    An option for the cameras of the HESS telescopes, the concept of a modular camera based on 'Smart Pixels' was developed. A Smart Pixel contains the photomultiplier, the high voltage supply for the photomultiplier, a dual-gain sample-and-hold circuit with a 14 bit dynamic range, a time-to-voltage converter, a trigger discriminator, trigger logic to detect a coincidence of X=1...7 neighboring pixels, and an analog ratemeter. The Smart Pixels plug into a common backplane which provides power, communicates trigger signals between neighboring pixels, and holds a digital control bus as well as an analog bus for multiplexed readout of pixel signals. The performance of the Smart Pixels has been studied using a 19-pixel test camera

  16. HPS Electronic Ballast Based on CIC-CPPFC Technique

    Institute of Scientific and Technical Information of China (English)

    王卫; 苏勤; 高国安

    2002-01-01

    Investigates the application of CIC-CPPFC techniques to high-pressure sodium(HPS) lamp electronic ballast. In order to ensure a unity power factor, different power electronic ballasts are studied by PSpice simulation. A dynamic model of HPS lamp with simple and accurate features is proposed for further study of characteristics. Experimental results verify the feasibility of HPS lamp operating at high frequency. It is shown that the presented electronic ballast has 0.99 power factor and 9% total harmonic distortion(THD).

  17. ID-Based Fair Off-Line Electronic Cash System with Multiple Banks

    Institute of Scientific and Technical Information of China (English)

    Chang-Ji Wang; Yong Tang; Qing Li

    2007-01-01

    ID-based public key cryptography (ID-PKC) has many advantages over certificate-based public key cryptog-raphy (CA-PKC), and has drawn researchers’ extensive attention in recent years. However, the existing electronic cash schemes are constructed under CA-PKC, and there seems no electronic cash scheme under ID-PKC up to now to the best of our knowledge. It is important to study how to construct electronic cash schemes based on ID-PKC from views on both practical perspective and pure research issue. In this paper, we present a simpler and provably secure ID-based restrictive partially blind signature (RPBS), and then propose an ID-based fair off-line electronic cash (ID-FOLC) scheme with multiple banks based on the proposed ID-based RPBS. The proposed ID-FOLC scheme with multiple banks is more efficient than existing electronic cash schemes with multiple banks based on group blind signature.

  18. Optical polarimeter based on Fourier analysis and electronic control

    International Nuclear Information System (INIS)

    In this paper, we show the design and implementation of an optical polarimeter using electronic control and the Fourier analysis. The polarimeter prototype will be used as a main tool for the students of the Universidad Popular del Cesar that belong to the following university programs: Electronics engineering (optoelectronics area), Math and Physics degree and the Master in Physics Sciences, in order to learning the theory and experimental aspects of the state of optical polarization via the Stokes vector measurement. Using the electronic polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the states of optical polarization when the optical waves pass through to the polarizers and retarder waves plates. The electronic polarimeter has a software that captures the optical intensity measurement and evaluates the Stokes vector. (Author)

  19. An experimental distribution of analog and digital information in a hybrid wireless visible light communication system based on acousto-optic modulation and sinusoidal gratings

    International Nuclear Information System (INIS)

    In this paper we propose a photonic architecture as an alternative tool to distribute point to multipoint analog and digital information over a hybrid wireless visible optical communication system. The experimental set-up is composed of a red laser pointer, an acousto-optic modulator, a sinusoidal grating and a photo-detector array. By using a simple and variable interferometric system, diffraction gratings with different spatial frequencies are generated and recorded on a photoemulsion which is composed of vanilla with dichromate gelatin. Analog video and digital information are first transmitted and recovered over a wireless communication system using a microwave carrier at 4.52 GHz which is generated by distributed feedback lasers operating in the low laser threshold current region. Separately, the recovered video information and digital data are combined with a radio frequency signal of 80 MHz, obtaining a subcarrier of information that is imposed on the optical carrier of the pointer laser using an acousto-optic modulator which is operated with an angle of incident light that satisfies the Bragg condition. The modulated optical carrier is sent to a sinusoidal grating, the diffraction pattern is photo-detected using an array of PIN photo-detectors. The use of sinusoidal gratings with acousto-optic modulators allows that number of channels to be increased when both components are placed in cascade. (paper)

  20. An experimental distribution of analog and digital information in a hybrid wireless visible light communication system based on acousto-optic modulation and sinusoidal gratings

    Science.gov (United States)

    Gómez Colín, R.; García Juárez, A.; Zaldívar Huerta, I. E.; Marquina, A. Vera; García Delgado, L. A.; Leal Cruz, A. L.; Gómez Fuentes, R.

    2016-03-01

    In this paper we propose a photonic architecture as an alternative tool to distribute point to multipoint analog and digital information over a hybrid wireless visible optical communication system. The experimental set-up is composed of a red laser pointer, an acousto-optic modulator, a sinusoidal grating and a photo-detector array. By using a simple and variable interferometric system, diffraction gratings with different spatial frequencies are generated and recorded on a photoemulsion which is composed of vanilla with dichromate gelatin. Analog video and digital information are first transmitted and recovered over a wireless communication system using a microwave carrier at 4.52 GHz which is generated by distributed feedback lasers operating in the low laser threshold current region. Separately, the recovered video information and digital data are combined with a radio frequency signal of 80 MHz, obtaining a subcarrier of information that is imposed on the optical carrier of the pointer laser using an acousto-optic modulator which is operated with an angle of incident light that satisfies the Bragg condition. The modulated optical carrier is sent to a sinusoidal grating, the diffraction pattern is photo-detected using an array of PIN photo-detectors. The use of sinusoidal gratings with acousto-optic modulators allows that number of channels to be increased when both components are placed in cascade.