WorldWideScience

Sample records for annealing

  1. Quantum annealing

    OpenAIRE

    Ruiz, Alfonso de la Fuente

    2014-01-01

    Brief description on the state of the art of some local optimization methods: Quantum annealing Quantum annealing (also known as alloy, crystallization or tempering) is analogous to simulated annealing but in substitution of thermal activation by quantum tunneling. The class of algorithmic methods for quantum annealing (dubbed: 'QA'), sometimes referred by the italian school as Quantum Stochastic Optimization ('QSO'), is a promising metaheuristic tool for solving local search problems in mult...

  2. Simulated annealing versus quantum annealing

    Science.gov (United States)

    Troyer, Matthias

    Based on simulated classical annealing and simulated quantum annealing using quantum Monte Carlo (QMC) simulations I will explore the question where physical or simulated quantum annealers may outperform classical optimization algorithms. Although the stochastic dynamics of QMC simulations is not the same as the unitary dynamics of a quantum system, I will first show that for the problem of quantum tunneling between two local minima both QMC simulations and a physical system exhibit the same scaling of tunneling times with barrier height. The scaling in both cases is O (Δ2) , where Δ is the tunneling splitting. An important consequence is that QMC simulations can be used to predict the performance of a quantum annealer for tunneling through a barrier. Furthermore, by using open instead of periodic boundary conditions in imaginary time, equivalent to a projector QMC algorithm, one obtains a quadratic speedup for QMC, and achieve linear scaling in Δ. I will then address the apparent contradiction between experiments on a D-Wave 2 system that failed to see evidence of quantum speedup and previous QMC results that indicated an advantage of quantum annealing over classical annealing for spin glasses. We find that this contradiction is resolved by taking the continuous time limit in the QMC simulations which then agree with the experimentally observed behavior and show no speedup for 2D spin glasses. However, QMC simulations with large time steps gain further advantage: they ``cheat'' by ignoring what happens during a (large) time step, and can thus outperform both simulated quantum annealers and classical annealers. I will then address the question how to optimally run a simulated or physical quantum annealer. Investigating the behavior of the tails of the distribution of runtimes for very hard instances we find that adiabatically slow annealing is far from optimal. On the contrary, many repeated relatively fast annealing runs can be orders of magnitude faster for

  3. Faster annealing schedules for quantum annealing

    OpenAIRE

    Morita, Satoshi

    2007-01-01

    New annealing schedules for quantum annealing are proposed based on the adiabatic theorem. These schedules exhibit faster decrease of the excitation probability than a linear schedule. To derive this conclusion, the asymptotic form of the excitation probability for quantum annealing is explicitly obtained in the limit of long annealing time. Its first-order term, which is inversely proportional to the square of the annealing time, is shown to be determined only by the information at the initi...

  4. Quantum Annealing for Clustering

    OpenAIRE

    Kurihara, Kenichi; Tanaka, Shu; Miyashita, Seiji

    2014-01-01

    This paper studies quantum annealing (QA) for clustering, which can be seen as an extension of simulated annealing (SA). We derive a QA algorithm for clustering and propose an annealing schedule, which is crucial in practice. Experiments show the proposed QA algorithm finds better clustering assignments than SA. Furthermore, QA is as easy as SA to implement.

  5. Generalized Simulated Annealing

    OpenAIRE

    Tsallis, Constantino; Stariolo, Daniel A.

    1995-01-01

    We propose a new stochastic algorithm (generalized simulated annealing) for computationally finding the global minimum of a given (not necessarily convex) energy/cost function defined in a continuous D-dimensional space. This algorithm recovers, as particular cases, the so called classical ("Boltzmann machine") and fast ("Cauchy machine") simulated annealings, and can be quicker than both. Key-words: simulated annealing; nonconvex optimization; gradient descent; generalized statistical mechan...

  6. Multivariable Optimization: Quantum Annealing & Computation

    OpenAIRE

    Mukherjee, Sudip; Chakrabarti, Bikas K.

    2014-01-01

    Recent developments in quantum annealing techniques have been indicating potential advantage of quantum annealing for solving NP-hard optimization problems. In this article we briefly indicate and discuss the beneficial features of quantum annealing techniques and compare them with those of simulated annealing techniques. We then briefly discuss the quantum annealing studies of some model spin glass and kinetically constrained systems.

  7. General Simulated Annealing

    Institute of Scientific and Technical Information of China (English)

    姚新; 李国杰

    1991-01-01

    Simulated annealing is a new kind of random search methods developed in recent years.It can also be considered as an extension to the classical hill-climbing method in AI--probabilistic hill-cimbing.One of its most important features is its global convergence.The convergence of simulated annealing algorithm is determined by state generating probability,state accepting probability,and temperature decreasing rate,This paper gives a generalized simulated annealing algorithm with dynamic generating and accepting probabilities.The paper also shows that the generating and accepting probabilities can adopt many different kinds of distributions while the global convergence is guaranteed.

  8. Nested Quantum Annealing Correction

    OpenAIRE

    Vinci, Walter; Albash, Tameem; Lidar, Daniel A.

    2015-01-01

    We present a general error-correcting scheme for quantum annealing that allows for the encoding of a logical qubit into an arbitrarily large number of physical qubits. Given any Ising model optimization problem, the encoding replaces each logical qubit by a complete graph of degree $C$, representing the distance of the error-correcting code. A subsequent minor-embedding step then implements the encoding on the underlying hardware graph of the quantum annealer. We demonstrate experimentally th...

  9. Temperature control during annealing

    International Nuclear Information System (INIS)

    Temperature control at a weld between a tube and tube plate having heat input from an inductive heating probe to effect annealing of the weld is performed with the aid of a signal generating receptor coil coupled with the probe. The signal from the coil experiences a characteristic change when the temperature of the weld reaches the required annealing temperature and this signal is used to control the heat input to the weld. The receptor coil can be inside the tube, outside the tube, embracing a number of similar tubes, or may be inside an adjacent tube. At the required anneal temperature, the materials of the tube and weld reach their Curie point which brings about a permeability change. (author)

  10. Reactor pressure vessel thermal annealing

    International Nuclear Information System (INIS)

    The steel plates and/or forgings and welds in the beltline region of a reactor pressure vessel (RPV) are subject to embrittlement from neutron irradiation. This embrittlement causes the fracture toughness of the beltline materials to be less than the fracture toughness of the unirradiated material. Material properties of RPVs that have been irradiated and embrittled are recoverable through thermal annealing of the vessel. The amount of recovery primarily depends on the level of the irradiation embrittlement, the chemical composition of the steel, and the annealing temperature and time. Since annealing is an option for extending the service lives of RPVs or establishing less restrictive pressure-temperature (P-T) limits; the industry, the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC) have assisted in efforts to determine the viability of thermal annealing for embrittlement recovery. General guidance for in-service annealing is provided in American Society for Testing and Materials (ASTM) Standard E 509-86. In addition, the American Society of Mechanical Engineers (ASME) Code Case N-557 addresses annealing conditions (temperature and duration), temperature monitoring, evaluation of loadings, and non-destructive examination techniques. The NRC thermal annealing rule (10 CFR 50.66) was approved by the Commission and published in the Federal Register on December 19, 1995. The Regulatory Guide on thermal annealing (RG 1.162) was processed in parallel with the rule package and was published on February 15, 1996. RG 1.162 contains a listing of issues that need to be addressed for thermal annealing of an RPV. The RG also provides alternatives for predicting re-embrittlement trends after the thermal anneal has been completed. This paper gives an overview of methodology and recent technical references that are associated with thermal annealing. Results from the DOE annealing prototype demonstration project, as well as NRC activities related to the

  11. multicast utilizando Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Yezid Donoso

    2005-01-01

    Full Text Available En este artículo se presenta un método de optimización multiobjetivo para la solución del problema de balanceo de carga en redes de transmisión multicast, apoyándose en la aplicación de la meta-heurística de Simulated Annealing (Recocido Simulado. El método minimiza cuatro parámetros básicos para garantizar la calidad de servicio en transmisiones multicast: retardo origen destino, máxima utilización de enlaces, ancho de banda consumido y número de saltos. Los resultados devueltos por la heurística serán comparados con los resultados arrojados por el modelo matemático propuesto en investigaciones anteriores.

  12. Radiation annealing in cuprous oxide

    DEFF Research Database (Denmark)

    Vajda, P.

    1966-01-01

    Experimental results from high-intensity gamma-irradiation of cuprous oxide are used to investigate the annealing of defects with increasing radiation dose. The results are analysed on the basis of the Balarin and Hauser (1965) statistical model of radiation annealing, giving a square...

  13. Quantum Annealing of Hard Problems

    OpenAIRE

    Jorg, Thomas; Krzakala, Florent; Kurchan, Jorge; Maggs, A C

    2009-01-01

    Quantum annealing is analogous to simulated annealing with a tunneling mechanism substituting for thermal activation. Its performance has been tested in numerical simulation with mixed conclusions. There is a class of optimization problems for which the efficiency can be studied analytically using techniques based on the statistical mechanics of spin glasses.

  14. Reactor vessel annealing system

    Science.gov (United States)

    Miller, Phillip E.; Katz, Leonoard R.; Nath, Raymond J.; Blaushild, Ronald M.; Tatch, Michael D.; Kordalski, Frank J.; Wykstra, Donald T.; Kavalkovich, William M.

    1991-01-01

    A system for annealing a vessel (14) in situ by heating the vessel (14) to a defined temperature, composed of: an electrically operated heater assembly (10) insertable into the vessel (14) for heating the vessel (14) to the defined temperature; temperature monitoring components positioned relative to the heater assembly (10) for monitoring the temperature of the vessel (14); a controllable electric power supply unit (32-60) for supplying electric power required by the heater assembly (10); a control unit (80-86) for controlling the power supplied by the power supply unit (32-60); a first vehicle (2) containing the power supply unit (32-60); a second vehicle (4) containing the control unit (80-86); power conductors (18,22) connectable between the power supply unit (32-60) and the heater unit (10) for delivering the power supplied by the power supply unit (32-60) to the heater assembly (10); signal conductors (20,24) connectable between the temperature monitoring components and the control unit (80-86) for delivering temperature indicating signals from the temperature monitoring components to the control unit (80-86); and control conductors (8) connectable between the control unit (80-86) and the power supply unit (32-60) for delivering to the power supply unit (32-60) control signals for controlling the level of power supplied by the power supply unit (32-60) to the heater assembly (10).

  15. Quantum annealing speedup over simulated annealing on random Ising chains

    CERN Document Server

    Zanca, Tommaso

    2015-01-01

    We show clear evidence of a speedup of a quantum annealing (QA) Schr\\"odinger dynamics over a Glauber master-equation simulated annealing (SA) for a random Ising model in one dimension. Annealings are tackled on equal footing, by a deterministic dynamics of the resulting Jordan-Wigner fermionic problems. We find that disorder, without frustration, makes both SA and real-time QA logarithmically slow in the annealing time $\\tau$, but QA shows a quadratic speedup with respect to SA. We also find that an imaginary-time Schr\\"odinger QA dynamics provides a further exponential speedup, with an asymptotic residual error compatible with a power-law $\\tau^{-\\mu}$.

  16. Irradiation and annealing sensitivity studies

    International Nuclear Information System (INIS)

    This report describes an evaluation of foreign steel production made to US guidelines for improved radiation resistance (new vessel forms) and investigations on radiation sensitivity and post-irradiation annealing for embrittlement relief (vessels produced 1971 or earlier). In the study of foreign steels, investigations coordinated by the IAEA and involving steels produced by West Germany, France, and Japan have confirmed the adequacy of the US-developed specifications. Progress of the Irradiation-Anneal-Reirradiation investigations are described, noting the synergism between copper impurities and nickel alloying in radiation sensitivity and annealing response. The PVI Surveillance Dosimetry Improvement Program, which as primary application to the more radiation sensitive vessels, is also discussed

  17. Stochastic Annealing for Variational Inference

    OpenAIRE

    Gultekin, San; Zhang, Aonan; Paisley, John

    2015-01-01

    We empirically evaluate a stochastic annealing strategy for Bayesian posterior optimization with variational inference. Variational inference is a deterministic approach to approximate posterior inference in Bayesian models in which a typically non-convex objective function is locally optimized over the parameters of the approximating distribution. We investigate an annealing method for optimizing this objective with the aim of finding a better local optimal solution and compare with determin...

  18. Austenite formation during intercritical annealing

    Directory of Open Access Journals (Sweden)

    A. Lis

    2008-07-01

    Full Text Available Purpose: of this paper is the effect of the soft annealing of initial microstructure of the 6Mn16 steel on the kinetics of the austenite formation during next intercritical annealing.Design/methodology/approach: Analytical TEM point analysis with EDAX system attached to Philips CM20 was used to evaluate the concentration of Mn, Ni and Cr in the microstructure constituents of the multiphase steel and mainly Bainite- Martensite islands.Findings: The increase in soft annealing time from 1-60 hours at 625°C increases Mn partitioning between ferrite and cementite and new formed austenite and decreases the rate of the austenite formation during next intercritical annealing in the (α+γ temperature range at 700 and 750°C. The general equations for carbide dissolution and austenite formation in intercritical temperature range were established.Research limitations/implications: The final multiphase microstructure can be optimised by changing the time / temperature parameters of the intercritical heating in the (α+γ temperature range.Originality/value: The knowledge of partitioning of alloying elements mainly Mn during soft annealing and intercritical heating is very important to optimise the processing technology of intercritical annealing for a given amount of the austenite.

  19. Quantum annealing speedup over simulated annealing on random Ising chains

    Science.gov (United States)

    Zanca, Tommaso; Santoro, Giuseppe E.

    2016-06-01

    We show clear evidence of a quadratic speedup of a quantum annealing (QA) Schrödinger dynamics over a Glauber master equation simulated annealing (SA) for a random Ising model in one dimension, via an equal-footing exact deterministic dynamics of the Jordan-Wigner fermionized problems. This is remarkable, in view of the arguments of H. G. Katzgraber et al. [Phys. Rev. X 4, 021008 (2014), 10.1103/PhysRevX.4.021008], since SA does not encounter any phase transition, while QA does. We also find a second remarkable result: that a "quantum-inspired" imaginary-time Schrödinger QA provides a further exponential speedup, i.e., an asymptotic residual error decreasing as a power law τ-μ of the annealing time τ .

  20. Thermal Annealing of Exfoliated Graphene

    Directory of Open Access Journals (Sweden)

    Wang Xueshen

    2013-01-01

    Full Text Available Monolayer graphene is obtained by mechanical exfoliation using scotch tapes. The effects of thermal annealing on the tape residues and edges of graphene are researched. Atomic force microscope images showed that almost all the residues could be removed in N2/H2 at 400°C but only agglomerated in vacuum. Raman spectra of the annealed graphene show both the 2D peak and G peak blueshift. The full width at half maximum (FWHM of the 2D peak becomes larger and the intensity ratio of the 2D peak to G peak decreases. The edges of graphene are completely attached to the surface of the substrate after annealing.

  1. Point defect annealing near voids

    International Nuclear Information System (INIS)

    Kinetic calculations were carried out for the annealing of vacancies and interstitials at voids under irradiation conditions. The case in which there is a small energy barrier between a defect and a void (such as might arise from strain effects or solute segregation at void surfaces) has been investigated in detail. With irradiation conditions which yield void swelling, it is found that a small barrier produces a significant bias parameter for preferential annealing. The bias parameter is relatively insensitive to temperature and irradiation rate, but varies with void radius, decreasing as the void size increases

  2. An Introduction to Simulated Annealing

    Science.gov (United States)

    Albright, Brian

    2007-01-01

    An attempt to model the physical process of annealing lead to the development of a type of combinatorial optimization algorithm that takes on the problem of getting trapped in a local minimum. The author presents a Microsoft Excel spreadsheet that illustrates how this works.

  3. Annealing properties of rice starch.

    Science.gov (United States)

    Thermal properties of starch can be modified by annealing, i.e., a pre-treatment in excessive amounts of water at temperatures below the gelatinization temperatures. This treatment is known to improve the crystalline properties, and is a useful tool to gain a better control of the functional proper...

  4. Ensemble annealing of complex physical systems

    CERN Document Server

    Habeck, Michael

    2015-01-01

    Algorithms for simulating complex physical systems or solving difficult optimization problems often resort to an annealing process. Rather than simulating the system at the temperature of interest, an annealing algorithm starts at a temperature that is high enough to ensure ergodicity and gradually decreases it until the destination temperature is reached. This idea is used in popular algorithms such as parallel tempering and simulated annealing. A general problem with annealing methods is that they require a temperature schedule. Choosing well-balanced temperature schedules can be tedious and time-consuming. Imbalanced schedules can have a negative impact on the convergence, runtime and success of annealing algorithms. This article outlines a unifying framework, ensemble annealing, that combines ideas from simulated annealing, histogram reweighting and nested sampling with concepts in thermodynamic control. Ensemble annealing simultaneously simulates a physical system and estimates its density of states. The...

  5. Residual Energies after Slow Quantum Annealing

    OpenAIRE

    Suzuki, Sei; Okada, Masato

    2005-01-01

    Features of the residual energy after the quantum annealing are investigated. The quantum annealing method exploits quantum fluctuations to search the ground state of classical disordered Hamiltonian. If the quantum fluctuation is reduced sufficiently slowly and linearly by the time, the residual energy after the quantum annealing falls as the inverse square of the annealing time. We show this feature of the residual energy by numerical calculations for small-sized systems and derive it on th...

  6. Hybrid Quantum Annealing for Clustering Problems

    OpenAIRE

    Tanaka, Shu; Tamura, Ryo; Sato, Issei; Kurihara, Kenichi

    2011-01-01

    We develop a hybrid type of quantum annealing in which we control temperature and quantum field simultaneously. We study the efficiency of proposed quantum annealing and find a good schedule of changing thermal fluctuation and quantum fluctuation. In this paper, we focus on clustering problems which are important topics in information science and engineering. We obtain the better solution of the clustering problem than the standard simulated annealing by proposed quantum annealing.

  7. Quantum annealing: An introduction and new developments

    OpenAIRE

    Ohzeki, Masayuki; Nishimori, Hidetoshi

    2010-01-01

    Quantum annealing is a generic algorithm using quantum-mechanical fluctuations to search for the solution of an optimization problem. The present paper first reviews the fundamentals of quantum annealing and then reports on preliminary results for an alternative method. The review part includes the relationship of quantum annealing with classical simulated annealing. We next propose a novel quantum algorithm which might be available for hard optimization problems by using a classical-quantum ...

  8. Ensemble annealing of complex physical systems

    OpenAIRE

    Habeck, Michael

    2015-01-01

    Algorithms for simulating complex physical systems or solving difficult optimization problems often resort to an annealing process. Rather than simulating the system at the temperature of interest, an annealing algorithm starts at a temperature that is high enough to ensure ergodicity and gradually decreases it until the destination temperature is reached. This idea is used in popular algorithms such as parallel tempering and simulated annealing. A general problem with annealing methods is th...

  9. Quantum Annealing for Variational Bayes Inference

    OpenAIRE

    Sato, Issei; Kurihara, Kenichi; Tanaka, Shu; Nakagawa, Hiroshi; Miyashita, Seiji

    2014-01-01

    This paper presents studies on a deterministic annealing algorithm based on quantum annealing for variational Bayes (QAVB) inference, which can be seen as an extension of the simulated annealing for variational Bayes (SAVB) inference. QAVB is as easy as SAVB to implement. Experiments revealed QAVB finds a better local optimum than SAVB in terms of the variational free energy in latent Dirichlet allocation (LDA).

  10. Non-Hermitian Quantum Annealing and Superradiance

    CERN Document Server

    Nesterov, Alexander I; de la Cruz, Fermín Aceves; Zepeda, Juan Carlos Beas

    2015-01-01

    We consider the non-Hermitian quantum annealing for the one-dimentional Ising spin chain, and for a large number of qubits. We show that the annealing time is significanly reduced for the non-Hermitian algorithm in comparison with the Hermitian one. We also demonstrtate the relation of the non-Hermitian quantum annealing with the superadiance transition in this system.

  11. Theory of radiation disordering and annealing semiconductors

    International Nuclear Information System (INIS)

    A new model of radiation disordering semiconductors is proposed. According to this model disordering clusters capable to the self-annealing are stabilized by autolocalized electronic excitations (electrons, holes, excitons). Impulse annealing this medium takes place if the electron stoppers are annihilated and so the disordered clusters are resolved. This model is in accordance with experimental data of amorphization and impulse annealing. (author)

  12. Feasibility of Simulated Annealing Tomography

    CERN Document Server

    Vo, Nghia T; Moser, Herbert O

    2014-01-01

    Simulated annealing tomography (SAT) is a simple iterative image reconstruction technique which can yield a superior reconstruction compared with filtered back-projection (FBP). However, the very high computational cost of iteratively calculating discrete Radon transform (DRT) has limited the feasibility of this technique. In this paper, we propose an approach based on the pre-calculated intersection lengths array (PILA) which helps to remove the step of computing DRT in the simulated annealing procedure and speed up SAT by over 300 times. The enhancement of convergence speed of the reconstruction process using the best of multiple-estimate (BoME) strategy is introduced. The performance of SAT under different conditions and in comparison with other methods is demonstrated by numerical experiments.

  13. Recursive simulation of quantum annealing

    CERN Document Server

    Sowa, A P; Samson, J H; Savel'ev, S E; Zagoskin, A M; Heidel, S; Zúñiga-Anaya, J C

    2015-01-01

    The evaluation of the performance of adiabatic annealers is hindered by lack of efficient algorithms for simulating their behaviour. We exploit the analyticity of the standard model for the adiabatic quantum process to develop an efficient recursive method for its numerical simulation in case of both unitary and non-unitary evolution. Numerical simulations show distinctly different distributions for the most important figure of merit of adiabatic quantum computing --- the success probability --- in these two cases.

  14. Recursive simulation of quantum annealing

    International Nuclear Information System (INIS)

    The evaluation of the performance of adiabatic annealers is hindered by the lack of efficient algorithms for simulating their behaviour. We exploit the analyticity of the standard model for the adiabatic quantum process to develop an efficient recursive method for its numerical simulation in case of both unitary and non-unitary evolution. Numerical simulations show distinctly different distributions for the most important figure of merit of adiabatic quantum computing—the success probability—in these two cases. (paper)

  15. Computational algorithm for molybdenite concentrate annealing

    International Nuclear Information System (INIS)

    Computational algorithm is presented for annealing of molybdenite concentrate with granulated return dust and that of granulated molybdenite concentrate. The algorithm differs from the known analogies for sulphide raw material annealing by including the calculation of return dust mass in stationary annealing; the latter quantity varies form the return dust mass value obtained in the first iteration step. Masses of solid products are determined by distribution of concentrate annealing products, including return dust and benthonite. The algorithm is applied to computations for annealing of other sulphide materials. 3 refs

  16. Very Fast Simulated Re-Annealing

    OpenAIRE

    Ingber, Lester

    1989-01-01

    Draft An algorithm is developed to statistically find the best global fit of a nonlinear non-convex cost-function over a D-dimensional space. It is argued that this algorithm permits an annealing schedule for ‘‘temperature’’ T decreasing exponentially in annealing-time k, T = T0 exp(−ck1/D). The introduction of re-annealing also permits adaptation to changing sensitivities in the multidimensional parameter-space. This annealing schedule is faster than fast Cauchy annealing, ...

  17. Annealing of ion implanted silicon

    International Nuclear Information System (INIS)

    The newer uses of ion implantation require a higher dose rate. This has led to the introduction of high beam current implanters; the wafers move in front of a stationary beam to give a scanning effect. This can lead to non-uniform heating of the wafer. Variations in the sheet resistance of the layers can be very non-uniform following thermal annealing. Non-uniformity in the effective doping both over a single wafer and from one wafer to another, can affect the usefulness of ion implantation in high dose rate applications. Experiments to determine the extent of non-uniformity in sheet resistance, and to see if it is correlated to the annealing scheme have been carried out. Details of the implantation parameters are given. It was found that best results were obtained when layers were annealed at the maximum possible temperature. For arsenic, phosphorus and antimony layers, improvements were observed up to 12000C and boron up to 9500C. Usually, it is best to heat the layer directly to the maximum temperature to produce the most uniform layer; with phosphorus layers however it is better to pre-heat to 10500C. (U.K.)

  18. Quantum Annealing for Constrained Optimization

    Science.gov (United States)

    Hen, Itay; Spedalieri, Federico M.

    2016-03-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealers that promise to solve certain combinatorial optimization problems of practical relevance faster than their classical analogues. The applicability of such devices for many theoretical and real-world optimization problems, which are often constrained, is severely limited by the sparse, rigid layout of the devices' quantum bits. Traditionally, constraints are addressed by the addition of penalty terms to the Hamiltonian of the problem, which, in turn, requires prohibitively increasing physical resources while also restricting the dynamical range of the interactions. Here, we propose a method for encoding constrained optimization problems on quantum annealers that eliminates the need for penalty terms and thereby reduces the number of required couplers and removes the need for minor embedding, greatly reducing the number of required physical qubits. We argue the advantages of the proposed technique and illustrate its effectiveness. We conclude by discussing the experimental feasibility of the suggested method as well as its potential to appreciably reduce the resource requirements for implementing optimization problems on quantum annealers and its significance in the field of quantum computing.

  19. Annealing study of poly(etheretherketone)

    Science.gov (United States)

    Cebe, Peggy

    1988-01-01

    Annealing of PEEK has been studied for two materials cold-crystallized from the rubbery amorphous state. The first material is a low molecular weight PEEK; the second is commercially available neat resin. Differential scanning calorimetry was used to monitor the melting behavior of annealed samples. The effect of thermal history on melting behavior is very complex and depends upon annealing temperature, residence time at the annealing temperature, and subsequent scanning rate. Thermal stability of both materials is improved by annealing, and for an annealing temperature near the melting point, the polymer can be stabilized against reorganization during the scan. Variations of density, degree of crystallinity, and X-ray long period were studied as a function of annealing temperature for the commercial material.

  20. Recursive Branching Simulated Annealing Algorithm

    Science.gov (United States)

    Bolcar, Matthew; Smith, J. Scott; Aronstein, David

    2012-01-01

    This innovation is a variation of a simulated-annealing optimization algorithm that uses a recursive-branching structure to parallelize the search of a parameter space for the globally optimal solution to an objective. The algorithm has been demonstrated to be more effective at searching a parameter space than traditional simulated-annealing methods for a particular problem of interest, and it can readily be applied to a wide variety of optimization problems, including those with a parameter space having both discrete-value parameters (combinatorial) and continuous-variable parameters. It can take the place of a conventional simulated- annealing, Monte-Carlo, or random- walk algorithm. In a conventional simulated-annealing (SA) algorithm, a starting configuration is randomly selected within the parameter space. The algorithm randomly selects another configuration from the parameter space and evaluates the objective function for that configuration. If the objective function value is better than the previous value, the new configuration is adopted as the new point of interest in the parameter space. If the objective function value is worse than the previous value, the new configuration may be adopted, with a probability determined by a temperature parameter, used in analogy to annealing in metals. As the optimization continues, the region of the parameter space from which new configurations can be selected shrinks, and in conjunction with lowering the annealing temperature (and thus lowering the probability for adopting configurations in parameter space with worse objective functions), the algorithm can converge on the globally optimal configuration. The Recursive Branching Simulated Annealing (RBSA) algorithm shares some features with the SA algorithm, notably including the basic principles that a starting configuration is randomly selected from within the parameter space, the algorithm tests other configurations with the goal of finding the globally optimal

  1. Thermal annealing, irradiation, and stress in multilayers

    International Nuclear Information System (INIS)

    The evolution of the microstructure of a TiN/B-C-N multilayered thin film during thermal annealing and irradiation has been studied by low angle X-ray diffraction and transmission electron microscopy. Stress has been determined by curvature measurements. After deposition, TiN is crystalline while B-C-N is amorphous. Thermal anneals in vacuum at 600-1000 deg. C lead to an increase of the bilayer repeat length and to a phase separation at the interfaces. After the 600 deg. C annealing, ion irradiation (Ar ions, 300 keV 1x1015 ions/cm2) causes an additional increase of the bilayer repeat length but a decrease of the quality of the interface. After annealing at 800 deg. C or 1000 deg. C, the irradiation causes a major decrease of the bilayer repeat length (more than 20% after annealing at 1000 deg. C and irradiation). The stress is highly compressive after deposition (σ=-2000 MPa). After the 600 deg. C annealing, the stress is totally relaxed (σ=0) and becomes tensile after annealing at higher temperatures (σ=+1200 MPa after 800 deg. C annealing, σ=+1500 MPa after 1000 deg. C annealing). TEM confirms the decrease of the bilayer repeat length after an irradiation of the samples subjected to high temperature anneal and reveal an increase of the roughness of the interfaces. These phenomena are discussed in terms of stress driven diffusion during irradiation

  2. Picosecond laser annealing of silicon

    International Nuclear Information System (INIS)

    The existing literature is reviewed and new results are presented on the regrowth of silicon surfaces, either virgin or amorphized by ion-implantation, following irradiation by picosecond laser pulses. The importance of melt depth, quench rate and the nature of the initial a-Si surface as revealed by cross-section TEM are emphasized in order to explain the unique halo patterns observed optically. A search for plasma annealing phenomena, as well as evidence for the buried molten layer proposed by other authors, both proved negative. (author)

  3. Loviisa Unit One: Annealing - healing

    Energy Technology Data Exchange (ETDEWEB)

    Kohopaeae, J.; Virsu, R. [ed.; Henriksson, A. [ed.

    1997-11-01

    Unit 1 of the Loviisa nuclear powerplant was annealed in connection with the refuelling outage in the summer of 1996. This type of heat treatment restored the toughness properties of the pressure vessel weld, which had been embrittled be neutron radiation, so that it is almost equivalent to a new weld. The treatment itself was an ordinary metallurgical procedure that took only a few days. But the material studies that preceded it began over fifteen years ago and have put IVO at the forefront of world-wide expertise in the area of radiation embrittlement

  4. Reverse annealing of boron doped polycrystalline silicon

    International Nuclear Information System (INIS)

    Thermal activation was carried out using polycrystalline silicon (poly-Si) produced through sequential-lateral-solidification or excimer-laser-crystallization (ELC) after B+ ion shower doping. The activation efficiency of the ELC samples was found to be higher than that of the SLS ones. In this regard, grain boundaries seemed to play a critical role in terms of the activation of dopants in poly-Si at low temperatures. Reverse annealing, in which a continuous loss of charge carriers occurs, was found in this study at temperatures ranging between 400 oC and 650 oC. The samples treated by rapid thermal annealing showed a lower sheet resistance than those treated by furnace annealing. Rapid thermal annealing was found to exhibit a higher activation efficiency than furnace annealing. Reverse annealing is believed to play an important role in terms of activation efficiency

  5. Reverse annealing of boron doped polycrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Beop-Jong; Hong, Won-Eui [Department of Materials Science and Engineering, Hongik University, Seoul, 121-791 (Korea, Republic of); Kim, Deok Hoi; Uemoto, Tstomu; Kim, Chi Woo [LTPS Team, AMLCD Business, Samsung Electronics, Yongin-City, Gyeonggi-Do, 449-711 (Korea, Republic of); Ro, Jae-Sang [Department of Materials Science and Engineering, Hongik University, Seoul, 121-791 (Korea, Republic of)], E-mail: jsang@wow.hongik.ac.kr

    2008-07-31

    Thermal activation was carried out using polycrystalline silicon (poly-Si) produced through sequential-lateral-solidification or excimer-laser-crystallization (ELC) after B{sup +} ion shower doping. The activation efficiency of the ELC samples was found to be higher than that of the SLS ones. In this regard, grain boundaries seemed to play a critical role in terms of the activation of dopants in poly-Si at low temperatures. Reverse annealing, in which a continuous loss of charge carriers occurs, was found in this study at temperatures ranging between 400 {sup o}C and 650 {sup o}C. The samples treated by rapid thermal annealing showed a lower sheet resistance than those treated by furnace annealing. Rapid thermal annealing was found to exhibit a higher activation efficiency than furnace annealing. Reverse annealing is believed to play an important role in terms of activation efficiency.

  6. Keystream Generator Based On Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Ayad A. Abdulsalam

    2011-01-01

    Full Text Available Advances in the design of keystream generator using heuristic techniques are reported. A simulated annealing algorithm for generating random keystream with large complexity is presented. Simulated annealing technique is adapted to locate these requirements. The definitions for some cryptographic properties are generalized, providing a measure suitable for use as an objective function in a simulated annealing algorithm, seeking randomness that satisfy both correlation immunity and the large linear complexity. Results are presented demonstrating the effectiveness of the method.

  7. Simulated Annealing using Hybrid Monte Carlo

    OpenAIRE

    Salazar, Rafael; Toral, Raúl

    1997-01-01

    We propose a variant of the simulated annealing method for optimization in the multivariate analysis of differentiable functions. The method uses global actualizations via the hybrid Monte Carlo algorithm in their generalized version for the proposal of new configurations. We show how this choice can improve upon the performance of simulated annealing methods (mainly when the number of variables is large) by allowing a more effective searching scheme and a faster annealing schedule.

  8. NEW SIMULATED ANNEALING ALGORITHMS FOR CONSTRAINED OPTIMIZATION

    OpenAIRE

    LINET ÖZDAMAR; CHANDRA SEKHAR PEDAMALLU

    2010-01-01

    We propose a Population based dual-sequence Non-Penalty Annealing algorithm (PNPA) for solving the general nonlinear constrained optimization problem. The PNPA maintains a population of solutions that are intermixed by crossover to supply a new starting solution for simulated annealing throughout the search. Every time the search gets stuck at a local optimum, this crossover procedure is triggered and simulated annealing search re-starts from a new subspace. In both the crossover and simulate...

  9. Magnetoimpedance response in current annealed amorphous wires

    International Nuclear Information System (INIS)

    In this work, the magnetoimpedance (MI) effect in amorphous wires submitted to current annealing treatment in vacuum is presented. The influence of circular anisotropy and stress relaxation induced during the annealing on the impedance dependence on external magnetic field is shown. An increase in the MI ratio for the annealed wires is observed up to a maximum value which is approximately three times higher than the maximum value obtained for the as-cast wire. For high enough times of current annealing treatment a decrease in the MI ratio is observed due to the formation of crystalline phase

  10. Magnetoimpedance response in current annealed amorphous wires

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, D. [Dpto. Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain)]. E-mail: danielgg@usal.es; Raposo, V. [Dpto. Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Borza, F. [Wolfson Centre for Magnetics Technology, Cardiff University, New Port Road, P.O. Box 925, CF24 0YF Cardiff (United Kingdom); Montero, O. [Dpto. Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Iniguez, J. [Dpto. Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain)

    2006-09-15

    In this work, the magnetoimpedance (MI) effect in amorphous wires submitted to current annealing treatment in vacuum is presented. The influence of circular anisotropy and stress relaxation induced during the annealing on the impedance dependence on external magnetic field is shown. An increase in the MI ratio for the annealed wires is observed up to a maximum value which is approximately three times higher than the maximum value obtained for the as-cast wire. For high enough times of current annealing treatment a decrease in the MI ratio is observed due to the formation of crystalline phase.

  11. Rapid Annealing Of Amorphous Hydrogenated Carbon

    Science.gov (United States)

    Alterovitz, Samuel A.; Pouch, John J.; Warner, Joseph D.

    1989-01-01

    Report describes experiments to determine effects of rapid annealing on films of amorphous hydrogenated carbon. Study represents first efforts to provide information for applications of a-C:H films where rapid thermal processing required. Major finding, annealing causes abrupt increase in absorption and concomitant decrease in optical band gap. Most of change occurs during first 20 s, continues during longer annealing times. Extend of change increases with annealing temperature. Researchers hypothesize abrupt initial change caused by loss of hydrogen, while gradual subsequent change due to polymerization of remaining carbon into crystallites or sheets of graphite. Optical band gaps of unannealed specimens on silicon substrates lower than those of specimens on quartz substrates.

  12. Classical Simulated Annealing Using Quantum Analogues

    Science.gov (United States)

    La Cour, Brian R.; Troupe, James E.; Mark, Hans M.

    2016-06-01

    In this paper we consider the use of certain classical analogues to quantum tunneling behavior to improve the performance of simulated annealing on a discrete spin system of the general Ising form. Specifically, we consider the use of multiple simultaneous spin flips at each annealing step as an analogue to quantum spin coherence as well as modifications of the Boltzmann acceptance probability to mimic quantum tunneling. We find that the use of multiple spin flips can indeed be advantageous under certain annealing schedules, but only for long anneal times.

  13. Classical Simulated Annealing Using Quantum Analogues

    Science.gov (United States)

    La Cour, Brian R.; Troupe, James E.; Mark, Hans M.

    2016-08-01

    In this paper we consider the use of certain classical analogues to quantum tunneling behavior to improve the performance of simulated annealing on a discrete spin system of the general Ising form. Specifically, we consider the use of multiple simultaneous spin flips at each annealing step as an analogue to quantum spin coherence as well as modifications of the Boltzmann acceptance probability to mimic quantum tunneling. We find that the use of multiple spin flips can indeed be advantageous under certain annealing schedules, but only for long anneal times.

  14. DOE`s annealing prototype demonstration projects

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J.; Nakos, J.; Rochau, G.

    1997-02-01

    One of the challenges U.S. utilities face in addressing technical issues associated with the aging of nuclear power plants is the long-term effect of plant operation on reactor pressure vessels (RPVs). As a nuclear plant operates, its RPV is exposed to neutrons. For certain plants, this neutron exposure can cause embrittlement of some of the RPV welds which can shorten the useful life of the RPV. This RPV embrittlement issue has the potential to affect the continued operation of a number of operating U.S. pressurized water reactor (PWR) plants. However, RPV material properties affected by long-term irradiation are recoverable through a thermal annealing treatment of the RPV. Although a dozen Russian-designed RPVs and several U.S. military vessels have been successfully annealed, U.S. utilities have stated that a successful annealing demonstration of a U.S. RPV is a prerequisite for annealing a licensed U.S. nuclear power plant. In May 1995, the Department of Energy`s Sandia National Laboratories awarded two cost-shared contracts to evaluate the feasibility of annealing U.S. licensed plants by conducting an anneal of an installed RPV using two different heating technologies. The contracts were awarded to the American Society of Mechanical Engineers (ASME) Center for Research and Technology Development (CRTD) and MPR Associates (MPR). The ASME team completed its annealing prototype demonstration in July 1996, using an indirect gas furnace at the uncompleted Public Service of Indiana`s Marble Hill nuclear power plant. The MPR team`s annealing prototype demonstration was scheduled to be completed in early 1997, using a direct heat electrical furnace at the uncompleted Consumers Power Company`s nuclear power plant at Midland, Michigan. This paper describes the Department`s annealing prototype demonstration goals and objectives; the tasks, deliverables, and results to date for each annealing prototype demonstration; and the remaining annealing technology challenges.

  15. Annealing Reduces Free Volumes In Thermoplastics

    Science.gov (United States)

    Singh, Jag J.; St. Clair, Terry L.

    1988-01-01

    Investigation conducted to determine free volumes and water-absorption characteristics of two types of thermoplastic polymide as functions of annealing histories. Reductions reach asymptotic values after several annealing cycles. High-temperature thermoplastics excellent candidates for use in aerospace applications. Graphite-fiber composites containing thermoplastic matrices have wide applicability.

  16. Cylinder packing by simulated annealing

    Directory of Open Access Journals (Sweden)

    M. Helena Correia

    2000-12-01

    Full Text Available This paper is motivated by the problem of loading identical items of circular base (tubes, rolls, ... into a rectangular base (the pallet. For practical reasons, all the loaded items are considered to have the same height. The resolution of this problem consists in determining the positioning pattern of the circular bases of the items on the rectangular pallet, while maximizing the number of items. This pattern will be repeated for each layer stacked on the pallet. Two algorithms based on the meta-heuristic Simulated Annealing have been developed and implemented. The tuning of these algorithms parameters implied running intensive tests in order to improve its efficiency. The algorithms developed were easily extended to the case of non-identical circles.Este artigo aborda o problema de posicionamento de objetos de base circular (tubos, rolos, ... sobre uma base retangular de maiores dimensões. Por razões práticas, considera-se que todos os objetos a carregar apresentam a mesma altura. A resolução do problema consiste na determinação do padrão de posicionamento das bases circulares dos referidos objetos sobre a base de forma retangular, tendo como objetivo a maximização do número de objetos estritamente posicionados no interior dessa base. Este padrão de posicionamento será repetido em cada uma das camadas a carregar sobre a base retangular. Apresentam-se dois algoritmos para a resolução do problema. Estes algoritmos baseiam-se numa meta-heurística, Simulated Annealling, cuja afinação de parâmetros requereu a execução de testes intensivos com o objetivo de atingir um elevado grau de eficiência no seu desempenho. As características dos algoritmos implementados permitiram que a sua extensão à consideração de círculos com raios diferentes fosse facilmente conseguida.

  17. A study on track annealing in Chaoyang No.1 polycarbonate

    International Nuclear Information System (INIS)

    This paper describes annealing characteristics of 208Pb and 93Nb ion tracks in Chaoyang No.1 polycarbonate, including the effect of annealing temperature on track etching rate and the effect of annealing temperature and annealing time on annealing rate. The result shows that activation energy of annealing for 208Pb and 93Nb in Chaoyang No.1 polycarbonate is 0.891 eV and 0.352 eV respectively

  18. Theory of Quantum Annealing of an Ising Spin Glass

    OpenAIRE

    Santoro, Giuseppe E.; Martonak, Roman; Tosatti, Erio; Car, Roberto

    2002-01-01

    Probing the lowest energy configuration of a complex system by quantum annealing was recently found to be more effective than its classical, thermal counterpart. Comparing classical and quantum Monte Carlo annealing protocols on the random two-dimensional Ising model we confirm the superiority of quantum annealing relative to classical annealing. We also propose a theory of quantum annealing, based on a cascade of Landau-Zener tunneling events. For both classical and quantum annealing, the re...

  19. Precision Laser Annealing of Focal Plane Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); DeRose, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Starbuck, Andrew Lea [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Verley, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jenkins, Mark W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We present results from laser annealing experiments in Si using a passively Q-switched Nd:YAG microlaser. Exposure with laser at fluence values above the damage threshold of commercially available photodiodes results in electrical damage (as measured by an increase in photodiode dark current). We show that increasing the laser fluence to values in excess of the damage threshold can result in annealing of a damage site and a reduction in detector dark current by as much as 100x in some cases. A still further increase in fluence results in irreparable damage. Thus we demonstrate the presence of a laser annealing window over which performance of damaged detectors can be at least partially reconstituted. Moreover dark current reduction is observed over the entire operating range of the diode indicating that device performance has been improved for all values of reverse bias voltage. Additionally, we will present results of laser annealing in Si waveguides. By exposing a small (<10 um) length of a Si waveguide to an annealing laser pulse, the longitudinal phase of light acquired in propagating through the waveguide can be modified with high precision, <15 milliradian per laser pulse. Phase tuning by 180 degrees is exhibited with multiple exposures to one arm of a Mach-Zehnder interferometer at fluence values below the morphological damage threshold of an etched Si waveguide. No reduction in optical transmission at 1550 nm was found after 220 annealing laser shots. Modeling results for laser annealing in Si are also presented.

  20. Simulated Quantum Annealing Can Be Exponentially Faster than Classical Simulated Annealing

    OpenAIRE

    Crosson, Elizabeth; Harrow, Aram W.

    2016-01-01

    Simulated Quantum Annealing (SQA) is a Markov Chain Monte-Carlo algorithm that samples the equilibrium thermal state of a Quantum Annealing (QA) Hamiltonian. In addition to simulating quantum systems, SQA has also been proposed as another physics-inspired classical algorithm for combinatorial optimization, alongside classical simulated annealing. However, in many cases it remains an open challenge to determine the performance of both QA and SQA. One piece of evidence for the strength of Q...

  1. Quantum Annealing of a Disordered Magnet

    OpenAIRE

    Brooke, J.; Bitko, D.; Rosenbaum, T. F.; Aeppli, G.

    2001-01-01

    Traditional simulated annealing utilizes thermal fluctuations for convergence in optimization problems. Quantum tunneling provides a different mechanism for moving between states, with the potential for reduced time scales. We compare thermal and quantum annealing in a model disordered Ising magnet, Li\\sub{Ho}{0.44}\\sub{Y}{0.56}\\sub{F}{4}, where the effects of quantum mechanics can be tuned in the laboratory by varying a magnetic field applied transverse to the Ising axis. Our results indicat...

  2. Adaptive simulated annealing (ASA): Lessons learned

    OpenAIRE

    Ingber, L.

    2000-01-01

    Adaptive simulated annealing (ASA) is a global optimization algorithm based on an associated proof that the parameter space can be sampled much more efficiently than by using other previous simulated annealing algorithms. The author's ASA code has been publicly available for over two years. During this time the author has volunteered to help people via e-mail, and the feedback obtained has been used to further develop the code. Some lessons learned, in particular some which are relevant to ot...

  3. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.;

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  4. Irradiation embrittlement and optimisation of annealing

    International Nuclear Information System (INIS)

    This conference is composed of 30 papers grouped in 6 sessions related to the following themes: neutron irradiation effects in pressure vessel steels and weldments used in PWR, WWER and BWR nuclear plants; results from surveillance programmes (irradiation induced damage and annealing processes); studies on the influence of variations in irradiation conditions and mechanisms, and modelling; mitigation of irradiation effects, especially through thermal annealing; mechanical test procedures and specimen size effects

  5. Morphological changes during annealing of polyethylene nanocrystals

    OpenAIRE

    Basu, Nandita; Osichow, Anna; Mecking, Stefan; Reiter, Günter

    2012-01-01

    Polymer crystals are metastable and exhibit morphological changes when being annealed. To observe morphological changes on molecular scales we started from small nanometer-sized crystals of highly folded long-chain polymers. Micron-sized stripes consisting of monolayers or stacks of several layers of flat-on oriented polyethylene nanocrystals were generated via evaporative dewetting from an aqueous dispersion. We followed the morphological changes in time and at progressively higher annealing...

  6. Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys

    Indian Academy of Sciences (India)

    Svetlana Nestorovic

    2005-08-01

    This paper reports results of investigation carried out on sintered copper alloys (Cu, 8 at%; Zn, Ni, Al and Cu–Au with 4 at%Au). The alloys were subjected to cold rolling (30, 50 and 70%) and annealed isochronally up to recrystallization temperature. Changes in hardness and electrical conductivity were followed in order to investigate the anneal hardening effect. This effect was observed after secondary annealing also. Au and Al have been found to be more effective in inducing anneal hardening effect.

  7. Direct observations of the vacancy and its annealing in germanium

    DEFF Research Database (Denmark)

    Slotte, J.; Kilpeläinen, S.; Tuomisto, F.;

    2011-01-01

    K. This is identified as the positron lifetime in a germanium monovacancy. Annealing experiments in the temperature interval 35–300 K reveal two annealing stages. The first at 100 K is tentatively associated with the annealing of the Frenkel pair, the second at 200 K with the annealing of the...

  8. Quantum Annealing and Quantum Fluctuation Effect in Frustrated Ising Systems

    OpenAIRE

    Tanaka, Shu; Tamura, Ryo

    2012-01-01

    Quantum annealing method has been widely attracted attention in statistical physics and information science since it is expected to be a powerful method to obtain the best solution of optimization problem as well as simulated annealing. The quantum annealing method was incubated in quantum statistical physics. This is an alternative method of the simulated annealing which is well-adopted for many optimization problems. In the simulated annealing, we obtain a solution of optimization problem b...

  9. Origin of reverse annealing effect in hydrogen-implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Di, Zengfeng [Los Alamos National Laboratory; Nastasi, Michael A [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory

    2009-01-01

    In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. On the basis of quantitative high resolution transmission electron microscopy combined with channeling Rutherford backscattering analysis, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induce platelets. Platelets are responsible for an increase in the height and width the channeling damage peak following increased isochronal anneals.

  10. The annealing robust backpropagation (ARBP) learning algorithm.

    Science.gov (United States)

    Chuang, C C; Su, S F; Hsiao, C C

    2000-01-01

    Multilayer feedforward neural networks are often referred to as universal approximators. Nevertheless, if the used training data are corrupted by large noise, such as outliers, traditional backpropagation learning schemes may not always come up with acceptable performance. Even though various robust learning algorithms have been proposed in the literature, those approaches still suffer from the initialization problem. In those robust learning algorithms, the so-called M-estimator is employed. For the M-estimation type of learning algorithms, the loss function is used to play the role in discriminating against outliers from the majority by degrading the effects of those outliers in learning. However, the loss function used in those algorithms may not correctly discriminate against those outliers. In this paper, the annealing robust backpropagation learning algorithm (ARBP) that adopts the annealing concept into the robust learning algorithms is proposed to deal with the problem of modeling under the existence of outliers. The proposed algorithm has been employed in various examples. Those results all demonstrated the superiority over other robust learning algorithms independent of outliers. In the paper, not only is the annealing concept adopted into the robust learning algorithms but also the annealing schedule k/t was found experimentally to achieve the best performance among other annealing schedules, where k is a constant and is the epoch number. PMID:18249835

  11. Computational multiqubit tunnelling in programmable quantum annealers

    Science.gov (United States)

    Boixo, Sergio; Smelyanskiy, Vadim N.; Shabani, Alireza; Isakov, Sergei V.; Dykman, Mark; Denchev, Vasil S.; Amin, Mohammad H.; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-01

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive.

  12. Hydrogen Annealing Of Single-Crystal Superalloys

    Science.gov (United States)

    Smialek, James L.; Schaeffer, John C.; Murphy, Wendy

    1995-01-01

    Annealing at temperature equal to or greater than 2,200 degrees F in atmosphere of hydrogen found to increase ability of single-crystal superalloys to resist oxidation when subsequently exposed to oxidizing atmospheres at temperatures almost as high. Supperalloys in question are principal constituents of hot-stage airfoils (blades) in aircraft and ground-based turbine engines; also used in other high-temperature applications like chemical-processing plants, coal-gasification plants, petrochemical refineries, and boilers. Hydrogen anneal provides resistance to oxidation without decreasing fatigue strength and without need for coating or reactive sulfur-gettering constituents. In comparison with coating, hydrogen annealing costs less. Benefits extend to stainless steels, nickel/chromium, and nickel-base alloys, subject to same scale-adhesion and oxidation-resistance considerations, except that scale is chromia instead of alumina.

  13. Simulation of Storm Occurrences Using Simulated Annealing.

    Science.gov (United States)

    Lokupitiya, Ravindra S.; Borgman, Leon E.; Anderson-Sprecher, Richard

    2005-11-01

    Modeling storm occurrences has become a vital part of hurricane prediction. In this paper, a method for simulating event occurrences using a simulated annealing algorithm is described. The method is illustrated using annual counts of hurricanes and of tropical storms in the Atlantic Ocean and Gulf of Mexico. Simulations closely match distributional properties, including possible correlations, in the historical data. For hurricanes, traditionally used Poisson and negative binomial processes also predict univariate properties well, but for tropical storms parametric methods are less successful. The authors determined that simulated annealing replicates properties of both series. Simulated annealing can be designed so that simulations mimic historical distributional properties to whatever degree is desired, including occurrence of extreme events and temporal patterning.

  14. Stochastic annealing simulation of cascades in metals

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, H.L.

    1996-04-01

    The stochastic annealing simulation code ALSOME is used to investigate quantitatively the differential production of mobile vacancy and SIA defects as a function of temperature for isolated 25 KeV cascades in copper generated by MD simulations. The ALSOME code and cascade annealing simulations are described. The annealing simulations indicate that the above Stage V, where the cascade vacancy clusters are unstable,m nearly 80% of the post-quench vacancies escape the cascade volume, while about half of the post-quench SIAs remain in clusters. The results are sensitive to the relative fractions of SIAs that occur in small, highly mobile clusters and large stable clusters, respectively, which may be dependent on the cascade energy.

  15. Infrared luminescence of annealed germanosilicate layers

    International Nuclear Information System (INIS)

    In the light of growing importance of semiconductor nanocrystals for photonics, we report on the growth and characterization of annealed germanosilicate layers used for Ge nanocrystal formation. The films are grown using plasma enhanced chemical vapor deposition (PECVD) and post-annealed in nitrogen at temperatures between 600 and 1200 °C for as long as 2 h. Transmission electron microscopy (TEM), Raman scattering and photoluminescence spectroscopy (PL) has been used to characterize the samples both structurally and optically. Formation of Ge precipitates in the germanosilicate layers have been observed using Raman spectroscopy for a variety of PECVD growth parameters, annealing temperatures and times. Ge–Ge mode at ∼300 cm−1 is clearly observed at temperatures as low as 700 °C for annealing durations for 45 min. Raman results indicate that upon annealing for extended periods of time at temperatures above 900 °C; nanocrystals of few tens of nanometers in diameter inside the oxide matrix and precipitation and interdiffusion of Ge, forming SiGe alloy at the silicon and oxide interface take place. Low temperature PL spectroscopy has been used to observe luminescence from these samples in the vicinity of 1550 nm, an important wavelength for telecommunications. Observed luminescence quenches at 140 K. The photoluminescence data displays three peaks closely interrelated at approximately 1490, 1530 and 1610 nm. PL spectra persist even after removing the oxide layer indicating that the origin of the infrared luminescent centers are not related to the Ge nanocrystals in the oxide layer. -- Highlights: • Nanostructures of Ge formed by precipitation of germanium in PECVD grown germanosilicate films were studied. • We have fabricated SiOx:Ge thin films using PECVD. • Annealing of SiOx:Ge films result in of formation of Ge nanocrystals and SiGe alloy the oxide Si interface. • Low temperature photoluminescence around 1500 nm has been indentified as Ge islands

  16. Infrared luminescence of annealed germanosilicate layers

    Energy Technology Data Exchange (ETDEWEB)

    Tokay, M.S. [Department of Physics, Kırıkkale University, 71450 Kırıkkale (Turkey); Yasar, E., E-mail: erdemyasar@kku.edu.tr [Department of Physics, Kırıkkale University, 71450 Kırıkkale (Turkey); Ağan, S. [Department of Physics, Kırıkkale University, 71450 Kırıkkale (Turkey); Aydınlı, A. [Department of Physics, Bilkent University, 06800 Ankara (Turkey)

    2014-03-15

    In the light of growing importance of semiconductor nanocrystals for photonics, we report on the growth and characterization of annealed germanosilicate layers used for Ge nanocrystal formation. The films are grown using plasma enhanced chemical vapor deposition (PECVD) and post-annealed in nitrogen at temperatures between 600 and 1200 °C for as long as 2 h. Transmission electron microscopy (TEM), Raman scattering and photoluminescence spectroscopy (PL) has been used to characterize the samples both structurally and optically. Formation of Ge precipitates in the germanosilicate layers have been observed using Raman spectroscopy for a variety of PECVD growth parameters, annealing temperatures and times. Ge–Ge mode at ∼300 cm{sup −1} is clearly observed at temperatures as low as 700 °C for annealing durations for 45 min. Raman results indicate that upon annealing for extended periods of time at temperatures above 900 °C; nanocrystals of few tens of nanometers in diameter inside the oxide matrix and precipitation and interdiffusion of Ge, forming SiGe alloy at the silicon and oxide interface take place. Low temperature PL spectroscopy has been used to observe luminescence from these samples in the vicinity of 1550 nm, an important wavelength for telecommunications. Observed luminescence quenches at 140 K. The photoluminescence data displays three peaks closely interrelated at approximately 1490, 1530 and 1610 nm. PL spectra persist even after removing the oxide layer indicating that the origin of the infrared luminescent centers are not related to the Ge nanocrystals in the oxide layer. -- Highlights: • Nanostructures of Ge formed by precipitation of germanium in PECVD grown germanosilicate films were studied. • We have fabricated SiOx:Ge thin films using PECVD. • Annealing of SiOx:Ge films result in of formation of Ge nanocrystals and SiGe alloy the oxide Si interface. • Low temperature photoluminescence around 1500 nm has been indentified as Ge

  17. Quantum annealing correction with minor embedding

    Science.gov (United States)

    Vinci, Walter; Albash, Tameem; Paz-Silva, Gerardo; Hen, Itay; Lidar, Daniel A.

    2015-10-01

    Quantum annealing provides a promising route for the development of quantum optimization devices, but the usefulness of such devices will be limited in part by the range of implementable problems as dictated by hardware constraints. To overcome constraints imposed by restricted connectivity between qubits, a larger set of interactions can be approximated using minor embedding techniques whereby several physical qubits are used to represent a single logical qubit. However, minor embedding introduces new types of errors due to its approximate nature. We introduce and study quantum annealing correction schemes designed to improve the performance of quantum annealers in conjunction with minor embedding, thus leading to a hybrid scheme defined over an encoded graph. We argue that this scheme can be efficiently decoded using an energy minimization technique provided the density of errors does not exceed the per-site percolation threshold of the encoded graph. We test the hybrid scheme using a D-Wave Two processor on problems for which the encoded graph is a two-level grid and the Ising model is known to be NP-hard. The problems we consider are frustrated Ising model problem instances with "planted" (a priori known) solutions. Applied in conjunction with optimized energy penalties and decoding techniques, we find that this approach enables the quantum annealer to solve minor embedded instances with significantly higher success probability than it would without error correction. Our work demonstrates that quantum annealing correction can and should be used to improve the robustness of quantum annealing not only for natively embeddable problems but also when minor embedding is used to extend the connectivity of physical devices.

  18. Annealing Increases Stability Of Iridium Thermocouples

    Science.gov (United States)

    Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.; Ahmed, Shaffiq

    1989-01-01

    Metallurgical studies carried out on samples of iridium versus iridium/40-percent rhodium thermocouples in condition received from manufacturer. Metallurgical studies included x-ray, macroscopic, resistance, and metallographic studies. Revealed large amount of internal stress caused by cold-working during manufacturing, and large number of segregations and inhomogeneities. Samples annealed in furnace at temperatures from 1,000 to 2,000 degree C for intervals up to 1 h to study effects of heat treatment. Wire annealed by this procedure found to be ductile.

  19. Topologically Ordered Graph Clustering via Deterministic Annealing

    OpenAIRE

    Rossi, Fabrice; Villa-Vialaneix, Nathalie

    2009-01-01

    This paper proposes an organized generalization of Newman and Girvan's modularity measure for graph clustering. Optimized via a deterministic annealing scheme, this measure produces topologically ordered graph partitions that lead to faithful and readable graph representations on a 2 dimensional SOM like planar grid.

  20. Hierarchical Network Design Using Simulated Annealing

    DEFF Research Database (Denmark)

    Thomadsen, Tommy; Clausen, Jens

    2002-01-01

    networks are described and a mathematical model is proposed for a two level version of the hierarchical network problem. The problem is to determine which edges should connect nodes, and how demand is routed in the network. The problem is solved heuristically using simulated annealing which as a sub...

  1. Interference Alignment Using Variational Mean Field Annealing

    DEFF Research Database (Denmark)

    Badiu, Mihai Alin; Guillaud, Maxime; Fleury, Bernard Henri

    2014-01-01

    We study the problem of interference alignment in the multiple-input multiple- output interference channel. Aiming at minimizing the interference leakage power relative to the receiver noise level, we use the deterministic annealing approach to solve the optimization problem. In the corresponding...

  2. Thermal annealing in neutron-irradiated tribromobenzenes

    DEFF Research Database (Denmark)

    Siekierska, K.E.; Halpern, A.; Maddock, A. G.

    1968-01-01

    The distribution of 82Br among various products in neutron-irradiated isomers of tribromobenzene has been investigated, and the effect of thermal annealing examined. Reversed-phase partition chromatography was employed for the determination of radioactive organic products, and atomic bromine in the...

  3. Positron prevacancy effects in pure annealed metals

    International Nuclear Information System (INIS)

    The low-temperature prevacancy effects sometimes observed with positrons in well-annealed high-purity metals are discussed. It is shown that these effects are not experimental artifacts, but are due to trapping of the positrons. It is suggested that dislocations are responsible for these trapping effects. 46 references, 5 figures

  4. Annealing of gold nanostructures sputtered on polytetrafluoroethylene

    Science.gov (United States)

    Siegel, Jakub; Krajcar, Robert; Kolská, Zdeňka; Hnatowicz, Vladimír; Švorčík, Václav

    2011-11-01

    Gold nanolayers sputtered on polytetrafluoroethylene (PTFE) surface and their changes induced by post-deposition annealing at 100°C to 300°C are studied. Changes in surface morphology and roughness are examined by atomic force microscopy, electrical sheet resistance by two point technique, zeta potential by electrokinetic analysis and chemical composition by X-ray photoelectron spectroscopy (XPS) in dependence on the gold layer thickness. Transition from discontinuous to continuous gold coverage takes place at the layer thicknesses 10 to 15 nm and this threshold remains practically unchanged after the annealing at the temperatures below 200°C. The annealing at 300°C, however, leads to significant rearrangement of the gold layer and the transition threshold increases to 70 nm. Significant carbon contamination and the presence of oxidized structures on gold-coated samples are observed in XPS spectra. Gold coating leads to a decrease in the sample surface roughness. Annealing at 300°C of pristine PTFE and gold-coated PTFE results in significant increase of the sample surface roughness.

  5. Annealing Ni nanocrystalline on WC-Co

    International Nuclear Information System (INIS)

    The effects of annealing temperature on nanocrystalline sputter-deposited Ni thin films (500 nm) deposited on WC-Co (4 wt.%) were investigated. Special attention was focused on quantitative evaluation of residual stress and Ni diffusion into the WC-Co, after heat treatment, from 873 to 1273 K. The estimated level of residual stress, as measured by X-ray diffraction, is around -1.3 ± 0.1 GPa for the as-deposited film, whereas after annealing at 1273 K it decreases significantly. Atomic force microscopy shows that high annealing temperature results into an exponential increase of the roughness. An intermixing between the nanocrystalline Ni and the Co from WC substrate occurs, as it is revealed by quantitative depth-resolved Rutherford backscattering spectrometry analysis and also supported by X-ray photoelectron spectroscopy. We ascribe a significant stress relief with the increasing annealing temperature to the diffusion process. The understanding of this process is particularly important in WC-Co parts with the surface treated with Ni in order to improve the maximum surface service temperature.

  6. Annealing Ni nanocrystalline on WC-Co

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, C.M.; Guisbiers, G.; Pereira, S. [CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Barradas, N.P.; Alves, E. [Nuclear and Technological Institute, E.N. 10, 2686-953 Sacavem (Portugal); Senos, A.M.R., E-mail: anamor@ua.p [CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Vieira, M.T. [Mechanical Engineering Department, ICEMS, Polo II, 3030-201 Coimbra (Portugal)

    2009-08-12

    The effects of annealing temperature on nanocrystalline sputter-deposited Ni thin films (500 nm) deposited on WC-Co (4 wt.%) were investigated. Special attention was focused on quantitative evaluation of residual stress and Ni diffusion into the WC-Co, after heat treatment, from 873 to 1273 K. The estimated level of residual stress, as measured by X-ray diffraction, is around -1.3 +- 0.1 GPa for the as-deposited film, whereas after annealing at 1273 K it decreases significantly. Atomic force microscopy shows that high annealing temperature results into an exponential increase of the roughness. An intermixing between the nanocrystalline Ni and the Co from WC substrate occurs, as it is revealed by quantitative depth-resolved Rutherford backscattering spectrometry analysis and also supported by X-ray photoelectron spectroscopy. We ascribe a significant stress relief with the increasing annealing temperature to the diffusion process. The understanding of this process is particularly important in WC-Co parts with the surface treated with Ni in order to improve the maximum surface service temperature.

  7. Cauchy Annealing Schedule: An Annealing Schedule for Boltzmann Selection Scheme in Evolutionary Algorithms

    OpenAIRE

    Dukkipati, Ambedkar; Murty, Narasimha M; Bhatnagar, Shalabh

    2004-01-01

    Boltzmann selection is an important selection mechanism in evolutionary algorithms as it has theoretical properties which help in theoretical analysis. However, Boltzmann selection is not used in practice because a good annealing schedule for the `inverse temperature' parameter is lacking. In this paper we propose a Cauchy annealing schedule for Boltzmann selection scheme based on a hypothesis that selection-strength should increase as evolutionary process goes on and distance between two sel...

  8. Laser annealing of amorphous silicon core optical fibers

    OpenAIRE

    Healy, N; Mailis, S.; Day, T. D.; Sazio, P.J.A.; Badding, J. V.; A.C. Peacock

    2012-01-01

    Laser annealing of an optical fiber with an amorphous silicon core is demonstrated. The annealing process produces a fiber that has a highly crystalline core, whilst reducing the optical transmission losses by ~3 orders of magnitude.

  9. Hypocoercivity in metastable settings and kinetic simulated annealing

    OpenAIRE

    Monmarché, Pierre

    2015-01-01

    Classical analysis of the simulated annealing algorithm is combined with the more recent hypocoercive method of distorted entropy to prove the convergence for large time of the kinetic Langevin annealing with logarithmic cooling schedule.

  10. Aplikasi Simulasi Annealing Untuk Menyelesaikan Traveling Salesman Problem

    OpenAIRE

    Larasati, Tuti

    2012-01-01

    Traveling salesman problem is one of combinatorial optimization problems that aim to obtain an optimal solution which determines the route that most minimum. And to resolve and find solutions to these problems one algorithm to be used is simulated annealing. Simulated annealing is an analogy of a liquid metals cooling process called annealing. Annealing is the metallurgical process of heating up a solid and then cooling slowly until it crystallizes. At this final task will shown an analogy an...

  11. Corrosion Behaviour of Annealed Cnx/Tiny Multilayers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-dong; PAN Chun-xu; FU Qiang; ZHANG Fu-ju; ZOU Yang; ZHANG Shao-hua

    2004-01-01

    The corrosion behaviour of annealed CNx/TiNy multilayers have been investigated using potentiodynamic test in a 0.5MH2SO4 solution. The coating has been deposited on W6Mo5Cr4V2 steel by reactive magnetron sputtering and then annealed at different temperature. The annealed multilayers showed superior corrosion resistance as compared to the as-deposited coating. The corrosion model of annealed CNx/TiNy multilayers has been set up.

  12. Corrosion Behaviour of Annealed Cnx/Tiny Multilayers

    Institute of Scientific and Technical Information of China (English)

    ZHANGGuo-dong; PANChun-xu; FUQiang; ZHANGFu-ju; ZOUYang; ZHANGShao-hua

    2004-01-01

    The corrosion behaviour of annealed CNx/TiNy multilayers have been investigated using potentiodynamic test in a 0.5MH2SO4 solution. The coating has been deposited on W6MoSCr4V2 steel by reactive magnetron sputtering and then annealed at different temperature. The annealed multilayers showed superior corrosion resistance as compared to the as-deposited coating, The corrosion model of annealed CNx/TiNy multilayers has been set up.

  13. Simulated Annealing with Tsallis Weights - A Numerical Comparison

    OpenAIRE

    Hansmann, Ulrich H.E.

    1997-01-01

    We discuss the use of Tsallis generalized mechanics in simulated annealing algorithms. For a small peptide it is shown that older implementations are not more effective than regular simulated annealing in finding ground state configurations. We propose a new implementation which leads to an improvement over regular simulated annealing.

  14. On lumped models for thermodynamic properties of simulated annealing problems

    OpenAIRE

    Andresen, Bjarne; Hoffmann, Karl Heinz; Mosegaard, Klaus; Nulton, Jim; Pedersen, Jacob Mørch; Salamon, Peter

    1988-01-01

    The paper describes a new method for the estimation of thermodynamic properties for simulated annealing problems using data obtained during a simulated annealing run. The method works by estimating energy-to-energy transition probabilities and is well adapted to simulations such as simulated annealing, in which the system is never in equilibrium.

  15. An Effect of Annealing on Shielding Properties of Shungite

    Science.gov (United States)

    Belousova, E. S.; Mahmoud, M. Sh.; Lynkou, L. M.

    2013-05-01

    Annealing of shungite is studied in oxidizing conditions in a chamber with NH4Cl, and in vacuum at 900 °C for 2h. Frequency dependencies of transmission and reflection coefficients of annealed shungite are measured in the frequency range of 8-12 GHz. The minimum reflection at 8-10 GHz was shown for shungite annealed in the oxidizing atmosphere.

  16. Laser beam annealing of heavily damaged implanted layers on silicon

    International Nuclear Information System (INIS)

    The behavior during annealing of heavily doped silicon layers obtained by high current density ion implantation is investigated. The annealing is performed by a laser pulse and the surface layers are studied by Rutherford backscattering, SIMS, ellipsometry and conductivityy measurements. Comparisons with thermal annealing show the advantage of using laser pulses to restore the original cristallinity

  17. Learning FCM by chaotic simulated annealing

    International Nuclear Information System (INIS)

    Fuzzy cognitive map (FCM) is a directed graph, which shows the relations between essential components in complex systems. It is a very convenient, simple, and powerful tool, which is used in numerous areas of application. Experts who are familiar with the system components and their relations can generate a related FCM. There is a big gap when human experts cannot produce FCM or even there is no expert to produce the related FCM. Therefore, a new mechanism must be used to bridge this gap. In this paper, a novel learning method is proposed to construct FCM by using Chaotic simulated annealing (CSA). The proposed method not only is able to construct FCM graph topology but also is able to extract the weight of the edges from input historical data. The efficiency of the proposed method is shown via comparison of its results of some numerical examples with those of Simulated annealing (SA) method.

  18. Simulated annealing in orbital flight planning

    Science.gov (United States)

    Soller, Jeffrey

    1990-01-01

    Simulated annealing is used to solve a minimum fuel trajectory problem in the space station environment. The environment is unique because the space station will define the first true multivehicle environment in space. The optimization yields surfaces which are potentially complex, with multiple local minima. Because of the likelihood of these local minima, descent techniques are unable to offer robust solutions. Other deterministic optimization techniques were explored without success. The simulated annealing optimization is capable of identifying a minimum-fuel, two-burn trajectory subject to four constraints. Furthermore, the computational efforts involved in the optimization are such that missions could be planned on board the space station. Potential applications could include the on-site planning of rendezvous with a target craft of the emergency rescue of an astronaut. Future research will include multiwaypoint maneuvers, using a knowledge base to guide the optimization.

  19. Thermal annealing of selected individual quantum dots

    International Nuclear Information System (INIS)

    Cathodoluminescence spectra of single InAs/GaAs quantum dots were recorded before and after consecutive thermal annealing steps. The annealing process leads to an overall blueshift of the spectra indicating In/Ga interdiffusion. Excitonic fine-structure splitting and binding energies of charged and neutral excitonic complexes were monitored. A drastic reduction of the fine-structure splitting from 170 μeV to less than 20 μeV can be observed accompanied by a change of the character of the biexciton from anti-binding to binding with respect to the exciton. Tailoring the fine-structure splitting is especially important for the use of single quantum dots in opto-electronic devices for quantum key distribution where a degeneracy of the exciton ground state (i.e. a fine-structure splitting below the homogeneous linewidth) is required for the on-demand production of entangled photon pairs

  20. Code Generator for Quantum Simulated Annealing

    CERN Document Server

    Tucci, Robert R

    2009-01-01

    This paper introduces QuSAnn v1.2 and Multiplexor Expander v1.2, two Java applications available for free. (Source code included in the distribution.) QuSAnn is a "code generator" for quantum simulated annealing: after the user inputs some parameters, it outputs a quantum circuit for performing simulated annealing on a quantum computer. The quantum circuit implements the algorithm of Wocjan et al. (arXiv:0804.4259), which improves on the original algorithm of Somma et al. (arXiv:0712.1008). The quantum circuit generated by QuSAnn includes some quantum multiplexors. The application Multiplexor Expander allows the user to replace each of those multiplexors by a sequence of more elementary gates such as multiply controlled NOTs and qubit rotations.

  1. Free electron laser annealing of silicon carbide

    International Nuclear Information System (INIS)

    We have studied the application of FEL for the semiconductor processing on the practical device fabrication. FEL annealing at a variety of wavelengths (10.0-13.0 μm) have been performed under room temperature for amorphous silicon carbide (a-SiC) and Nitrogen implanted cubic silicon carbide (3C-SiC) films. Infrared absorption spectroscopy indicated that the annealing at 12.6 μm, corresponding to the absorption peak of Si-C stretch mode, was effective for recrystallization. On the other hand, Hall effect measurements showed the increase of carrier density for N-implanted 3C-SiC films at around 10.4 μm, whereas the absorption was weak at this wavelength. The present results demonstrated that the direct excitation of the lattice vibration with FEL can induce the reconstruction of disordered atoms and activating dopants even at room temperature. (author)

  2. Comparison of Poly-Si Thin Films Prepared by Conventional Furnace Annealing and Pulsed Rapid Thermal Annealing

    Institute of Scientific and Technical Information of China (English)

    JIN Rui-min; ZHENG Xiao-yan; CHEN Lan-li; LUO Peng-hui; GUO Xin-feng; LU Jing-xiao

    2009-01-01

    Amorphous silicon films prepared by PECVD on glass substrate were crystallized by conventional furnace annealing (FA) and rapid thermal annealing ( RTA),respectively. From the Raman spectra and scanning electronic microscope(SEM),it found that the thin films made by RTA had smooth and perfect structure,while the thin films annealed by FA had a higher degree of structural disorder.

  3. Shock, Post-Shock Annealing, and Post-Annealing Shock in Ureilites

    Science.gov (United States)

    Rubin, Alan E.

    2006-01-01

    The thermal and shock histories of ureilites can be divided into four periods: 1) formation, 2) initial shock, 3) post-shock annealing, and 4) post-annealing shock. Period 1 occurred approx.4.55 Ga ago when ureilites formed by melting chondritic material. Impact events during period 2 caused silicate darkening, undulose to mosaic extinction in olivines, and the formation of diamond, lonsdaleite, and chaoite from indigenous carbonaceous material. Alkali-rich fine-grained silicates may have been introduced by impact injection into ureilites during this period. About 57% of the ureilites were unchanged after period 2. During period 3 events, impact-induced annealing caused previously mosaicized olivine grains to become aggregates of small unstrained crystals. Some ureilites experienced reduction as FeO at the edges of olivine grains reacted with C from the matrix. Annealing may also be responsible for coarsening of graphite in a few ureilites, forming euhedral-appearing, idioblastic crystals. Orthopyroxene in Meteorite Hills (MET) 78008 may have formed from pigeonite by annealing during this period. The Rb-Sr internal isochron age of approx.4.0 Ga for MET 78008 probably dates the annealing event. At this late date, impacts are the only viable heat source. About 36% of ureilites experienced period 3 events, but remained unchanged afterwards. During period 4, approx.7% of the ureilites were shocked again, as is evident in the polymict breccia, Elephant Moraine (EET) 83309. This rock contains annealed mosaicized olivine aggregates composed of small individual olivine crystals that exhibit undulose extinction. Ureilites may have formed by impact-melting chondritic material on a primitive body with heterogeneous O isotopes. Plagioclase was preferentially lost from the system due to its low impedance to shock compression. Brief melting and rapid burial minimized the escape of planetary-type noble gases from the ureilitic melts. Incomplete separation of metal from silicates

  4. Pyrolytic citrate synthesis and ozone annealing

    International Nuclear Information System (INIS)

    A pyrolytic procedure is described that via a citrate synthesis allowed us to obtain very fine grained YBCO powders that, after a first furnace thermal treatment in ozone, results already to contain a large amount of superconducting microcrystals. A second identical thermal treatment gives a final product strongly textured, as shown by magnetic torque measurements. Complementary structural and diamagnetic measurement show the high quality of these sintered pellets. The role covered by both the pyrolytic preparation and the ozone annealing are discussed

  5. Pyrolitic citrate synthesis and ozone annealing

    International Nuclear Information System (INIS)

    A pyrolytic procedure that via a citrate synthesis allowed to obtain very fine grained YBCO powders that, after a first furnace thermal treatment in ozone, result already to contain a large amount of superconducting microcystals is described. A second identical thermal treatment gives a final product strongly textured, as shown by magnetic torque measurements. Complementary structural and diamagnetic measurements show the high quality of these sintered pellets. The role covered by both the pyrolytic preparation and the ozone annealing are discussed

  6. Using Simulated Annealing to Factor Numbers

    OpenAIRE

    Altschuler, Eric Lewin; Williams, Timothy J.

    2014-01-01

    Almost all public secure communication relies on the inability to factor large numbers. There is no known analytic or classical numeric method to rapidly factor large numbers. Shor[1] has shown that a quantum computer can factor numbers in polynomial time but there is no practical quantum computer that can yet do such computations. We show that a simulated annealing[2] approach can be adapted to find factors of large numbers.

  7. MEDICAL STAFF SCHEDULING USING SIMULATED ANNEALING

    OpenAIRE

    Ladislav Rosocha; Silvia Vernerova; Robert Verner

    2015-01-01

    Purpose: The efficiency of medical staff is a fundamental feature of healthcare facilities quality. Therefore the better implementation of their preferences into the scheduling problem might not only rise the work-life balance of doctors and nurses, but also may result into better patient care. This paper focuses on optimization of medical staff preferences considering the scheduling problem. Methodology/Approach: We propose a medical staff scheduling algorithm based on simulated annealing, a...

  8. MEDICAL STAFF SCHEDULING USING SIMULATED ANNEALING

    OpenAIRE

    Ladislav Rosocha; Silvia Vernerova; Robert Verner

    2015-01-01

    Purpose: The efficiency of medical staff is a fundamental feature of healthcare facilities quality. Therefore the better implementation of their preferences into the scheduling problem might not only rise the work-life balance of doctors and nurses, but also may result into better patient care. This paper focuses on optimization of medical staff preferences considering the scheduling problem.Methodology/Approach: We propose a medical staff scheduling algorithm based on simulated annealing, a ...

  9. Laser-annealing of thin semiconductor films

    OpenAIRE

    Boneberg, Johannes; Nedelcu, Johann; Bucher, Ernst; Leiderer, Paul

    1994-01-01

    Optical reflectivity and transmissivity measurements have been used to investigate the dynamics of melting and recrystallisation of thin films of Si and Ge after laser-annealing with a ns Nd:YAG-laser pulse. We report on temperature dependent changes of the reflectivity of the liquid phase above and below the melting point and on various nucleation and solidification scenarios in thin film, depending on the energy density of the amding laser.

  10. Solving maximum cut problems by simulated annealing

    OpenAIRE

    Myklebust, Tor G. J.

    2015-01-01

    This paper gives a straightforward implementation of simulated annealing for solving maximum cut problems and compares its performance to that of some existing heuristic solvers. The formulation used is classical, dating to a 1989 paper of Johnson, Aragon, McGeoch, and Schevon. This implementation uses no structure peculiar to the maximum cut problem, but its low per-iteration cost allows it to find better solutions than were previously known for 40 of the 89 standard maximum cut instances te...

  11. Thermal annealing of fission fragment radiation damage in CR-39

    International Nuclear Information System (INIS)

    The annealing behavior of fission fragment tracks in CR-39 has been studied at different temperatures for various time intervals. Experimental data, obtained in isothermal and isochronal annealing experiments carried out on CR-39 irradiated with fission fragments of 252Cf, has been analyzed on the basis of different annealing models. It has been attempted to find out the validity of these models, developed on the basis of annealing data in minerals and other detectors, to the annealing data of fission fragment tracks in CR-39

  12. Annealing of Solar Cells and Other Thin Film Devices

    Science.gov (United States)

    Escobar, Hector; Kuhlman, Franz; Dils, D. W.; Lush, G. B.; Mackey, Willie R. (Technical Monitor)

    2001-01-01

    Annealing is a key step in most semiconductor fabrication processes, especially for thin films where annealing enhances performance by healing defects and increasing grain sizes. We have employed a new annealing oven for the annealing of CdTe-based solar cells and have been using this system in an attempt to grow US on top of CdTe by annealing in the presence of H2S gas. Preliminary results of this process on CdTe solar cells and other thin-film devices will be presented.

  13. Stored energy and annealing behavior of heavily deformed aluminium

    DEFF Research Database (Denmark)

    Kamikawa, Naoya; Huang, Xiaoxu; Kondo, Yuka;

    2012-01-01

    It has been demonstrated in previous work that a two-step annealing treatment, including a low-temperature, long-time annealing and a subsequent high-temperature annealing, is a promising route to control the microstructure of a heavily deformed metal. In the present study, structural parameters...... 175°C followed by 0.5 h annealing at 200-600°C, where the former treatment leads to discontinuous recrystallization and the latter to uniform structural coarsening. This behavior has been analyzed in terms of the relative change during annealing of energy stored as elastic energy in the dislocation...

  14. Study Of Microstructure And Hardness Of Assab Corrax Steel Annealing

    International Nuclear Information System (INIS)

    Hardness testing and microstructures investigation have been performed at annealed Assab Corrax steel. This preliminary research is gain to look for the high temperature operation resisting materials. The steels were annealed to observe grains and hardness changes in two ways; annealing-temperature constant (400oC) and annealing-time hold constant (4 hours). The results show that the hardness vs. time-hold fluctuates between 200 Hv and 400 Hv, meanwhile it tends to increase due to precipitation hardening by means annealing temperatures. In summary, the hardness is unpredictable by means time-hold and it improves due to precipitation role. The surface micrographs support the phenomena

  15. Simulated annealing with probabilistic analysis for solving traveling salesman problems

    Science.gov (United States)

    Hong, Pei-Yee; Lim, Yai-Fung; Ramli, Razamin; Khalid, Ruzelan

    2013-09-01

    Simulated Annealing (SA) is a widely used meta-heuristic that was inspired from the annealing process of recrystallization of metals. Therefore, the efficiency of SA is highly affected by the annealing schedule. As a result, in this paper, we presented an empirical work to provide a comparable annealing schedule to solve symmetric traveling salesman problems (TSP). Randomized complete block design is also used in this study. The results show that different parameters do affect the efficiency of SA and thus, we propose the best found annealing schedule based on the Post Hoc test. SA was tested on seven selected benchmarked problems of symmetric TSP with the proposed annealing schedule. The performance of SA was evaluated empirically alongside with benchmark solutions and simple analysis to validate the quality of solutions. Computational results show that the proposed annealing schedule provides a good quality of solution.

  16. Annealing texture of nanostructured IF steel

    International Nuclear Information System (INIS)

    In the present work, the evolution of annealing texture in nanostructured interstitial free steel fabricated via accumulative roll bonding (ARB) process was investigated. Textural evolution after post-annealing of ARB-processed samples was evaluated using X-ray diffraction. There were several texture transitions in the γ-fiber and ζ-fiber during ARB and post-annealing treatment. It was found that with increasing the number of ARB cycles, the volume fraction of the low angle grain boundary decreased and the high angle grain boundary fraction increased. Also, the shear texture was dominant after the first cycle, while for other samples, the rolling texture was dominant. The one-cycle sample clearly indicated a weak α-fiber and γ-fiber and a relatively strong ζ-fiber. In addition, during the recrystallization and before the grain growth, the intensity of α-fiber and γ-fiber decreased, the intensity of ζ-fiber increased, and the intensity of (011)〈100〉 orientation in the ε-fiber and η-fiber increased. Moreover, it was concluded that the transition from the rolling texture to the shear one was a sign of occurrence of the recrystallization (before the grain growth). Finally, with increasing the number of ARB cycles, the intensity of rolling and shear textures saturated and a stable texture formed. - Highlights: • There were texture transitions in the γ-fiber and ζ-fiber. • When the number of cycles increased, the low angle grain boundaries decreased. • The shear texture was dominant after the first cycle. • Transition from rolling texture to shear one was a sign of recrystallization. • With increasing the number of ARB cycles, a stable texture formed

  17. Error correction for encoded quantum annealing

    Science.gov (United States)

    Pastawski, Fernando; Preskill, John

    2016-05-01

    Recently, W. Lechner, P. Hauke, and P. Zoller [Sci. Adv. 1, e1500838 (2015), 10.1126/sciadv.1500838] have proposed a quantum annealing architecture, in which a classical spin glass with all-to-all pairwise connectivity is simulated by a spin glass with geometrically local interactions. We interpret this architecture as a classical error-correcting code, which is highly robust against weakly correlated bit-flip noise, and we analyze the code's performance using a belief-propagation decoding algorithm. Our observations may also apply to more general encoding schemes and noise models.

  18. Binary Sparse Phase Retrieval via Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Wei Peng

    2016-01-01

    Full Text Available This paper presents the Simulated Annealing Sparse PhAse Recovery (SASPAR algorithm for reconstructing sparse binary signals from their phaseless magnitudes of the Fourier transform. The greedy strategy version is also proposed for a comparison, which is a parameter-free algorithm. Sufficient numeric simulations indicate that our method is quite effective and suggest the binary model is robust. The SASPAR algorithm seems competitive to the existing methods for its efficiency and high recovery rate even with fewer Fourier measurements.

  19. Batch-annealed dual-phase steel

    International Nuclear Information System (INIS)

    Dual-phase steel, consisting essentially of a ferrite matrix containing islands of martensite, is produced by batch annealing of hot or cold rolled steel having carbon below 0.2% and manganese below 2% and at least critical contents of copper (0.4%) and nickel (0.6%), with heat to the alpha plus gamma region, followed by slow cooling. This procedure is effective and controllable, and yields a dual-phase steel product that has high tensile strength with excellent elongation properties and that develops good yield strength upon moderate deformation

  20. Annealing relaxation of ultrasmall gold nanostructures

    Science.gov (United States)

    Chaban, Vitaly

    2015-01-01

    Except serving as an excellent gift on proper occasions, gold finds applications in life sciences, particularly in diagnostics and therapeutics. These applications were made possible by gold nanoparticles, which differ drastically from macroscopic gold. Versatile surface chemistry of gold nanoparticles allows coating with small molecules, polymers, biological recognition molecules. Theoretical investigation of nanoscale gold is not trivial, because of numerous metastable states in these systems. Unlike elsewhere, this work obtains equilibrium structures using annealing simulations within the recently introduced PM7-MD method. Geometries of the ultrasmall gold nanostructures with chalcogen coverage are described at finite temperature, for the first time.

  1. Annealing-induced Ge/Si(100) island evolution

    International Nuclear Information System (INIS)

    Ge/Si(100) islands were found to coarsen during in situ annealing at growth temperature. Islands were grown by molecular-beam epitaxy of pure Ge and annealed at substrate temperatures of T=450, 550, 600, and 650 deg. C, with Ge coverages of 6.5, 8.0, and 9.5 monolayers. Three coarsening mechanisms operate in this temperature range: wetting-layer consumption, conventional Ostwald ripening, and Si interdiffusion. For samples grown and annealed at T=450 deg. C, consumption of a metastably thick wetting layer causes rapid initial coarsening. Slower coarsening at longer annealing times occurs by conventional Ostwald ripening. Coarsening of samples grown and annealed at T=550 deg. C occurs via a combination of Si interdiffusion and conventional Ostwald ripening. For samples grown and annealed at T≥600 deg. C, Ostwald ripening of SiGe alloy clusters appears to be the dominant coarsening mechanism

  2. Microstructural evolution of ECAPed 1050 alloy under magnetic annealing

    Science.gov (United States)

    Cao, Yi-heng; Jia, Pin-feng; Wang, Kang; He, Li-zi; Wang, Ping; Cui, Jian-zhong

    2014-12-01

    Hardness and microstructure evolutions in 1050 aluminum alloy prepared by equal-channel angular pressing (ECAP) were investigated by hardness testing, optical microscopy, and transmission electron microscopy after samples were annealed at different temperatures for 1 h both in the absence and presence of a 12-T magnetic field. The results showed that the hardness of samples after magnetic annealing were lower than that of samples after normal annealing at 150-250°C, but it was higher than that of samples after normal annealing at >250°C. During annealing, the rate of softening was faster, and the grains were more homogeneous in 8-ECAPed samples than in 2-ECAPed samples. A rapid grain growth occurred when 2-ECAPed samples were annealed at high temperature (≥300°C). The magnetic field enhanced the mobility of dislocations and grain boundaries. A more homogeneous grain size was observed in samples prepared under an applied magnetic field.

  3. Visible photoluminescence from the annealed TEOS SiO2

    International Nuclear Information System (INIS)

    We report the visible photoluminescence (PL) excited by Ar-ion laser (514.5 nm) at room temperature from the TEOS SiO2 films annealed under the protection of flowing N2. It was found that the PL peak position located at between 610 and 640 nm does not significantly change with the annealing temperature (T anneal). The PL intensity of TEOS SiO2 films first exhibits a gradual increase as T anneal is below 850 deg. C; thereafter it keeps almost constant when 850 deg. C anneal anneal is increased up to 1200 deg. C. The results of Raman scattering, Fourier-Transform infrared absorption and X-ray photoelectron spectra indicate that the PL mechanism in TEOS SiO2 films should be attributed to the defect emission at the surface of the SiO2 film

  4. Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

    Directory of Open Access Journals (Sweden)

    Afarin Bahrami

    2012-01-01

    Full Text Available Porous silicon (PSi layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm2 fixed current density for different etching times. The samples were coated with a 50–60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM. Photoacoustic spectroscopy (PAS measurements were carried out to measure the thermal diffusivity (TD of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing.

  5. Study on thermal annealing of cadmium zinc telluride (CZT) crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.; Bolotnikov, A.E.; Fochuk, P.M.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.; Horace, J.; McCall, B.; Gul, R.; Xu, L.; Kopach, O.V.; and James, R.B.

    2010-08-01

    Cadmium Zinc Telluride (CZT) has attracted increasing interest with its promising potential as a room-temperature nuclear-radiation-detector material. However, different defects in CZT crystals, especially Te inclusions and dislocations, can degrade the performance of CZT detectors. Post-growth annealing is a good approach potentially to eliminate the deleterious influence of these defects. At Brookhaven National Laboratory (BNL), we built up different facilities for investigating post-growth annealing of CZT. Here, we report our latest experimental results. Cd-vapor annealing reduces the density of Te inclusions, while large temperature gradient promotes the migration of small-size Te inclusions. Simultaneously, the annealing lowers the density of dislocations. However, only-Cd-vapor annealing decreases the resistivity, possibly reflecting the introduction of extra Cd in the lattice. Subsequent Te-vapor annealing is needed to ensure the recovery of the resistivity after removing the Te inclusions.

  6. The role of particles annealing temperature on magnetorheological effect

    OpenAIRE

    Sedlačík, M.; Pavlínek, V.; Sáha, P.; Švrčinová, P. (Petra); Filip, P.

    2012-01-01

    The spinel nanocrystalline cobalt ferrite (CoFe.sub.2./sub.O.sub.4./sub.) particles were prepared via a solgel method followed by the annealing process. Their structural, magnetic and magnetorheological (MR) properties depending upon the annealing temperature were investigated. The X-ray diffraction analysis revealed that the higher annealing temperature, the larger grain size of CoFe.sub.2./sub.O.sub.4./sub. particles resulting in larger magnetic domains in particles. The saturation magnetiz...

  7. Measures of Fault Tolerance in Distributed Simulated Annealing

    OpenAIRE

    Prakash, Aaditya

    2012-01-01

    In this paper, we examine the different measures of Fault Tolerance in a Distributed Simulated Annealing process. Optimization by Simulated Annealing on a distributed system is prone to various sources of failure. We analyse simulated annealing algorithm, its architecture in distributed platform and potential sources of failures. We examine the behaviour of tolerant distributed system for optimization task. We present possible methods to overcome the failures and achieve fault tolerance for t...

  8. The role of particles annealing temperature on magnetorheological effect

    OpenAIRE

    Sedlačík, M.; Pavlínek, V.; Sáha, P.; Švrčinová, P. (Petra); Filip, P.

    2011-01-01

    The spinel cobalt ferrite (CoFe.sub.2./sub.O.sub.4./sub.) nanoparticles were prepared via a sol-gel method followed by the annealing process. Their structural, magnetic and magnetorheological (MR) properties depending upon the annealing temperature were investigated. The X-ray diffraction analysis revealed that the higher annealing temperature, the larger grain size of CoFe.sub.2./sub.O.sub.4./sub. particles resulting in larger magnetic domains in particles. The saturation magnetization, dete...

  9. Simulated Annealing of Two Electron Density Solution Systems

    OpenAIRE

    Neto, Mario de Oliveira; Alonso, Ronaldo Luiz; Leite, Fabio Lima; Jr, Osvaldo N. Oliveira; Polikarpov, Igor; Mascarenhas, Yvonne Primerano

    2008-01-01

    Many structural studies have been performed with a combination of SAXS and simulated annealing to reconstruct three dimensional models. Simulated annealing is suitable for the study of monodisperse, diluted and two-electron densities systems. In this chapter we showed how the simulated annealing procedure can be used to minimize the discrepancy between two functions: the simulated intensity and the experimental one-dimensional SAXS curve. The goal was to find the most probable form for a prot...

  10. Tunneling through high energy barriers in simulated quantum annealing

    OpenAIRE

    Crosson, Elizabeth; Deng, Mingkai

    2014-01-01

    We analyze the performance of simulated quantum annealing (SQA) on an optimization problem for which simulated classical annealing (SA) is provably inefficient because of a high energy barrier. We present evidence that SQA can pass through this barrier to find the global minimum efficiently. This demonstrates the potential for SQA to inherit some of the advantages of quantum annealing (QA), since this problem has been previously shown to be efficiently solvable by quantum adiabatic optimization.

  11. Annealing effect and stability of carbon nanotubes in hydrogen flame

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Annealing of carbon nanotubes (CNTs) by the hydrogen flame in air was investigated in this study. Raman spectroscopy and scanning electron microscopy were used to characterize the products. The peak width of Raman spectra decreased with the increase in the annealing time. The CNTs were not stable in the hydrogen flame and the etching rate of the CNTs by hydrogen flame was very high. The hydrogen flame annealing had some effects on improving the crystallinity of CNTs.

  12. ANNEALING OF HOT-CARRIER-INDUCED MOSFET DEGRADATION

    OpenAIRE

    Mahnkopf, R.; Przyrembel, G.; Wagemann, H.

    1988-01-01

    The annealing of fixed oxide charge and interface states generated by hot-carrier stress is investigated in the temperature range of 100°C - 450°C. First order rate equations are given, which approximately describe two subsequent processes involved in the annealing and ending at neutralization. The related activation energies are determined. For comparison the annealing of synchrotron light induced damage is examined.

  13. Magnetic field annealing for improved creep resistance

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Michael P.; Ludtka, Gail M.; Ludtka, Gerard M.; Muralidharan, Govindarajan; Nicholson, Don M.; Rios, Orlando; Yamamoto, Yukinori

    2015-12-22

    The method provides heat-resistant chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloys having improved creep resistance. A precursor is provided containing preselected constituents of a chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloy, at least one of the constituents for forming a nanoscale precipitate MaXb where M is Cr, Nb, Ti, V, Zr, or Hf, individually and in combination, and X is C, N, O, B, individually and in combination, a=1 to 23 and b=1 to 6. The precursor is annealed at a temperature of 1000-1500.degree. C. for 1-48 h in the presence of a magnetic field of at least 5 Tesla to enhance supersaturation of the M.sub.aX.sub.b constituents in the annealed precursor. This forms nanoscale M.sub.aX.sub.b precipitates for improved creep resistance when the alloy is used at service temperatures of 500-1000.degree. C. Alloys having improved creep resistance are also disclosed.

  14. Annealing Would Improve beta" - Alumina Solid Electrolyte

    Science.gov (United States)

    Williams, Roger; Homer, Margie; Ryan, Margaret; Cortez, Roger; Shields, Virgil; Kisor, Adam

    2003-01-01

    A pre-operational annealing process is under investigation as a potential means of preventing a sudden reduction of ionic conductivity in a Beta"-alumina solid electrolyte (BASE) during use. On the basis of tests, the sudden reduction of ionic conductivity, followed by a slow recovery, has been found to occur during testing of the solid electrolyte and electrode components of an alkali metal thermal-to-electric converter (AMTEC) cell. At this time, high-temperature tests of limited duration have indicated the superiority of the treated BASE, but reproducible tests over thousands of hours are necessary to confirm that microcracking has been eliminated. The ionic conductivity of the treated BASE is also measured to be higher than untreated BASE at 1,073 K in low-pressure sodium vapor. Microcracking resulting in loss of conductivity was not observed with treated BASE in one high-temperature experiment, but this result must be duplicated over very long testing times to be sure of the effect. Shorter annealing times (10 to 20 hours) were found to result in significantly less loss of mass; it may be necessary for the packed powder mixture to evolve some Na2O before the Na2O can leave the ceramic.

  15. MEDICAL STAFF SCHEDULING USING SIMULATED ANNEALING

    Directory of Open Access Journals (Sweden)

    Ladislav Rosocha

    2015-07-01

    Full Text Available Purpose: The efficiency of medical staff is a fundamental feature of healthcare facilities quality. Therefore the better implementation of their preferences into the scheduling problem might not only rise the work-life balance of doctors and nurses, but also may result into better patient care. This paper focuses on optimization of medical staff preferences considering the scheduling problem.Methodology/Approach: We propose a medical staff scheduling algorithm based on simulated annealing, a well-known method from statistical thermodynamics. We define hard constraints, which are linked to legal and working regulations, and minimize the violations of soft constraints, which are related to the quality of work, psychic, and work-life balance of staff.Findings: On a sample of 60 physicians and nurses from gynecology department we generated monthly schedules and optimized their preferences in terms of soft constraints. Our results indicate that the final value of objective function optimized by proposed algorithm is more than 18-times better in violations of soft constraints than initially generated random schedule that satisfied hard constraints.Research Limitation/implication: Even though the global optimality of final outcome is not guaranteed, desirable solutionwas obtained in reasonable time. Originality/Value of paper: We show that designed algorithm is able to successfully generate schedules regarding hard and soft constraints. Moreover, presented method is significantly faster than standard schedule generation and is able to effectively reschedule due to the local neighborhood search characteristics of simulated annealing.

  16. Annealing conditions for intrinsic CdTe

    Science.gov (United States)

    Berding, M. A.

    1999-01-01

    Equilibrium native defect densities in CdTe are calculated from ab initio methods, and compared with experimental results. We find that CdTe is highly compensated p type under tellurium-saturated conditions, with the cadmium vacancy as the dominant acceptor and the tellurium antisite as the compensating donor. This finding is in agreement with recent experiments that find a much larger deviation from stoichiometry than would be predicted by the electrically active defects. Under cadmium-saturated conditions, cadmium interstitials are predicted to dominate and the material is found to be n type. Native defect concentrations and the corresponding carrier concentrations are predicted as a function of processing conditions, and can serve as a guide to postgrowth anneals to manipulate the conductivity of undoped material for applications in x- and γ-ray spectrometers. Furthermore, we show that by choosing appropriate annealing conditions and extrinsic dopants, one can increase the operating efficiency of nuclear spectrometers by reducing the density of specific native defects that produce midgap trapping states.

  17. Ballistic self-annealing during ion implantation

    International Nuclear Information System (INIS)

    Ion implantation conditions are considered during which the energy, dissipated in the collision cascades, is low enough to ensure that the defects, which are generated during these collisions, consist primarily of vacancies and interstitial atoms. It is proposed that ballistic self-annealing is possible when the point defect density becomes high enough, provided that none, or very few, of the interstitial atoms escape from the layer being implanted. Under these conditions, the fraction of ballistic atoms, generated within the collision cascades from substitutional sites, decreases with increasing ion dose. Furthermore, the fraction of ballistic atoms, which finally end up within vacancies, increases with increasing vacancy density. Provided the crystal structure does not collapse, a damage threshold should be approached where just as many atoms are knocked out of substitutional sites as the number of ballistic atoms that fall back into vacancies. Under these conditions, the average point defect density should approach saturation. This model is applied to recently published Raman data that have been measured on a 3 MeV He+-ion implanted diamond (Orwa et al 2000 Phys. Rev. B 62 5461). The conclusion is reached that this ballistic self-annealing model describes the latter data better than a model in which it is assumed that the saturation in radiation damage is caused by amorphization of the implanted layer. (author)

  18. Dielectric Signatures of Annealing in Glacier Ice

    Science.gov (United States)

    Grimm, R. E.; Stillman, D. E.; MacGregor, J. A.

    2015-12-01

    We analyzed the dielectric spectra of 49 firn and ice samples from ice sheets and glaciers to better understand how differing ice formation and evolution affect electrical properties. The dielectric relaxation of ice is well known and its characteristic frequency increases with the concentration of soluble impurities in the ice lattice. We found that meteoric ice and firn generally possess two such relaxations, indicating distinct crystal populations or zonation. Typically, one population is consistent with that of relatively pure ice, and the other is significantly more impure. However, high temperatures (e.g., temperate ice), long residence times (e.g., ancient ice from Mullins Glacier, Antarctica), or anomalously high impurity concentrations favor the development of a single relaxation. These relationships suggest that annealing causes two dielectrically distinct populations to merge into one population. The dielectric response of temperate ice samples indicates increasing purity with increasing depth, suggesting final rejection of impurities from the lattice. Separately, subglacially frozen samples from the Vostok 5G ice core possess a single relaxation whose variable characteristic frequency likely reflects the composition of the source water. Multi-frequency electrical measurements on cores and in the field can track annealing of glacier ice.

  19. A Parallel Genetic Simulated Annealing Hybrid Algorithm for Task Scheduling

    Institute of Scientific and Technical Information of China (English)

    SHU Wanneng; ZHENG Shijue

    2006-01-01

    In this paper combined with the advantages of genetic algorithm and simulated annealing, brings forward a parallel genetic simulated annealing hybrid algorithm (PGSAHA) and applied to solve task scheduling problem in grid computing .It first generates a new group of individuals through genetic operation such as reproduction, crossover, mutation, etc, and than simulated anneals independently all the generated individuals respectively.When the temperature in the process of cooling no longer falls, the result is the optimal solution on the whole.From the analysis and experiment result, it is concluded that this algorithm is superior to genetic algorithm and simulated annealing.

  20. Burst annealing of high temperature GaAs solar cells

    Science.gov (United States)

    Brothers, P. R.; Horne, W. E.

    1991-01-01

    One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles.

  1. Structure and magnetism of Ni/Ti multilayers on annealing

    Indian Academy of Sciences (India)

    Surendra Singh; Saibal Basu; P Bhatt

    2008-11-01

    Neutron reflectometry study has been carried out in unpolarized (NR) and polarized (PNR) mode to understand the structure and magnetic properties of alloy formation at the interfaces of Ni/Ti multilayers on annealing. The PNR data from annealed sample shows a noticeable change with respect to the as-deposited sample. These changes are: a prominent shift of the multilayer Bragg peak to a higher angle and a decrease in the intensity of the Bragg peak. The PNR data from annealed sample revealed the formation of magnetically dead alloy layers at the interfaces. Changes in roughness parameters of the interfaces on annealing were also observed in the PNR data.

  2. A laboratory flash furnace for strand annealing simulation

    Science.gov (United States)

    Page, J. H. R.

    1995-08-01

    The economic production of CRML steels depends on the use of continuous annealing. Successful development of improved CRML steels, the compositions of which have moved to lower carbon contents, is critically dependent on the rate of heating and its effect on transformation characteristics. As a result, accurate simulation of annealing conditions, particularly the heating rate, is essential. With this in mind, European Electrical Steels set criteria for a laboratory annealing facility that would, das far as was practicable, reproduce day- to- day continuous furnace operation. This paper outlines the design criteria, construction, and operation of the resulting annealing facility.

  3. A laboratory flash furnace for strand annealing simulation

    Energy Technology Data Exchange (ETDEWEB)

    Page, J.H.R. [European Electrical Steels, Newport (United Kingdom). Orb Works

    1995-08-01

    The economic production of CRML steels depends on the use of continuous annealing. Successful developed of improved CRML steels, the compositions of which have moved to lower carbon contents, is critically dependent on the rate of heating and its effect on transformation characteristics. As a result, accurate simulation of annealing conditions, particularly the heating rate, is essential. With this in mind, European Electrical Steels set criteria for a laboratory annealing facility that would, as far as was practicable, reproduce day-to-day continuous furnace operation. This paper outlines the design criteria, construction, and operation of the resulting annealing facility.

  4. Study of the optical properties of etched alpha tracks in annealed and non-annealed CR-39 polymeric detectors

    International Nuclear Information System (INIS)

    The UV–visible absorption spectra of virgin and alpha particle-irradiated, annealed and non-annealed CR-39 polymeric track detectors were investigated using a UV–visible spectrometer (Shimadzu mini 1240). Isothermal annealing experiments were carried out on poly allyl diglycol carbonate (PADC) films based nuclear track detectors (NTDs) exposed to a 241Am source. A shifting and broadening of the UV–visible peaks was observed as a result of the etched alpha tracks in the non-annealed and annealed PADC films. The UV–visible spectra of the virgin and non-annealed α-irradiated PADC polymer films displayed a decreasing trend in their optical energy band gaps, both direct and indirect, whereas those measured for the annealed α-irradiated ones showed no significant change. This drop in the energy band gap with increasing fluence is discussed on the basis of the alpha particle- and thermal annealing-induced modifications in the PADC polymeric detector. The results clearly showed that the values for the indirect energy band gap were lower than the corresponding values for the direct band gap. In addition, the Urbach energy was estimated from the Urbach edge, and exhibited roughly the same trend as the optical band gap. Finally, this study presents new results showing that the annealed PADC films were highly insensitive to alpha particles. - Highlights: • UV–visible absorption through etched alpha tracks in annealed and non-annealed PADC films was investigated. • Films of PADC based NTDs were irradiated with different fluences from alpha particles. • PADC film samples were annealed at a temperature of 120 °C for durations of 2, 4, 6, 8, and 10 h. • It is a good method for relative fluence or dose reading

  5. Advanced activation trends for boron and arsenic by combinations of single, multiple flash anneals and spike rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lerch, W. [Mattson Thermal Products GmbH, Daimlerstrasse 10, 89160 Dornstadt (Germany)], E-mail: wilfried.lerch@mattson.com; Paul, S.; Niess, J. [Mattson Thermal Products GmbH, Daimlerstrasse 10, 89160 Dornstadt (Germany); McCoy, S.; Gelpey, J. [Mattson Technology Canada Inc., 605 W. Kent Avenue, Vancouver, BC V6P6T7 Canada (Canada); Cristiano, F.; Severac, F. [LAAS/CNRS, 7 av. Du Col. Roche, 31077 Toulouse (France); Fazzini, P. [CEMES/CNRS, 29 rue G. Marvig, 31055 Toulouse (France); Martinez-Limia, A.; Pichler, P. [Fraunhofer-IISB, Schottkystrasse 10, 91058 Erlangen (Germany); Kheyrandish, H. [CSMA-MATS, Queens Road, Stoke on Trent ST4 7LQ (United Kingdom); Bolze, D. [IHP, Im Technologiepark 25, 15326 Frankfurt (Oder) (Germany)

    2008-12-05

    Millisecond annealing as an equipment technology provides temperature profiles which favour dopant activation but nearly eliminate dopant diffusion to form extremely shallow, highly electrically activated junctions. For the 45-nm technology node and beyond, precisely controlled gate under-diffusion is required for optimum device performance. Therefore, on boron and arsenic beamline-implanted wafers, various annealing schemes were investigated for the formation of ultra-shallow and custom-shaped junctions. The main scheme consisted of flash annealing with peak temperatures ranging from 1250 to 1300 deg. C, combined with spike rapid thermal annealing with peak temperatures in the range from 900 to 1000 deg. C to achieve a desired junction depth. As alternative, to reduce the sheet resistance of pMOS and nMOS source-drain extensions, combinations of two or three flash anneals in succession were tested. Finally, the standard flash anneal condition of a 750 deg. C intermediate temperature followed by the flash anneal was changed to a high intermediate temperature of 950 deg. C followed by the flash anneal up to 1300 deg. C. The results of all these annealing schemes were analysed by four-point probe measurement. Selected samples were analysed by Hall-effect measurements for peak activation, and by secondary ion mass spectrometry for profile shape as well as diffusion effects. Transmission electron microscopy was used to study residual defects. Selected boron and arsenic dopant profiles were also compared to predictive simulation results which address the diffusion and activation at extrinsic concentrations.

  6. Mechanical behavior of multipass welded joint during stress relief annealing

    International Nuclear Information System (INIS)

    An investigation into mechanical behavior of a multipass welded joint of a pressure vessel during stress relief annealing was conducted. The study was performed theoretically and experimentally on idealized research models. In the theoretical analysis, the thermal elastic-plastic creep theory developed by the authors was applied. The behavior of multipass welded joints during the entire thermal cycle, from welding to stress relief annealing, was consistently analyzed by this theory. The results of the analysis show a good, fundamentally coincidence with the experimental findings. The outline of the results and conclusions is as follows. (1) In the case of the material (2 1/4Cr-1Mo steel) furnished in this study, the creep strain rate during stress relief annealing below 5750C obeys the strain-hardening creep law using the transient creep and the one above 5750C obeys the power creep law using the stational creep. (2) In the transverse residual stress (σsub(x)) distribution after annealing, the location of the largest tensile stress on the top surface is about 15 mm away from the toe of weld, and the largest at the cross section is just below the finishing bead. These features are similar to those of welding residual stresses. But the stress distribution after annealing is smoother than one from welding. (3) The effectiveness of stress relief annealing depends greatly on the annealing temperature. For example, most of residual stresses are relieved at the heating stage with a heating rate of 300C/hr. to 1000C/hr. if the annealing temperature is 6500C, but if the annealing temperature is 5500C, the annealing is not effective even with a longer holding time. (4) In the case of multipass welding residual stresses studied in this paper, the behaviors of high stresses during annealing are approximated by ones during anisothermal relaxation. (auth.)

  7. Simulation of annealed polyelectrolytes in poor solvents

    International Nuclear Information System (INIS)

    We present (semi-)grand canonical Monte Carlo simulations on annealed polyelectrolytes in poor solvent. Increasing the chemical potential of the charges, which is equal to the pH of the solution except for a trivial additive constant, in rather poor solvents, we find the first-order phase transition between a weakly charged globule and a highly charged extended chain predicted by theory. In the close-to-Q -point regime, we investigate under which conditions pearl-necklace structures are stable. Most of the pearl-necklace parameters are found to obey the scaling relations predicted for quenched polyelectrolytes. However, similarly to the behavior known for this class of polyelectrolytes we obtain large fluctuations in pearl number and size. In agreement with theoretical predictions we find a non-uniform charge distribution between pearls and strings

  8. Thermoelectric properties by high temperature annealing

    Science.gov (United States)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Kumar, Shankar (Inventor); Lee, Hohyun (Inventor)

    2009-01-01

    The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.

  9. Simulated annealing algorithm for detecting graph isomorphism

    Institute of Scientific and Technical Information of China (English)

    Geng Xiutang; Zhang Kai

    2008-01-01

    Evolutionary computation techniques have mostly been used to solve various optimization problems,and it is well known that graph isomorphism problem (GIP) is a nondeterministic polynomial problem.A simulated annealing (SA) algorithm for detecting graph isomorphism is proposed,and the proposed SA algorithm is well suited to deal with random graphs with large size.To verify the validity of the proposed SA algorithm,simulations are performed on three pairs of small graphs and four pairs of large random graphs with edge densities 0.5,0.1,and 0.01,respectively.The simulation results show that the proposed SA algorithm can detect graph isomorphism with a high probability.

  10. Annealing a magnetic cactus into phyllotaxis

    Science.gov (United States)

    Nisoli, Cristiano; Gabor, Nathaniel M.; Lammert, Paul E.; Maynard, J. D.; Crespi, Vincent H.

    2010-04-01

    The appearance of mathematical regularities in the disposition of leaves on a stem, scales on a pine-cone, and spines on a cactus has puzzled scholars for millennia; similar so-called phyllotactic patterns are seen in self-organized growth, polypeptides, convection, magnetic flux lattices and ion beams. Levitov showed that a cylindrical lattice of repulsive particles can reproduce phyllotaxis under the (unproved) assumption that minimum of energy would be achieved by two-dimensional Bravais lattices. Here we provide experimental and numerical evidence that the Phyllotactic lattice is actually a ground state. When mechanically annealed, our experimental “magnetic cactus” precisely reproduces botanical phyllotaxis, along with domain boundaries (called transitions in Botany) between different phyllotactic patterns. We employ a structural genetic algorithm to explore the more general axially unconstrained case, which reveals multijugate (multiple spirals) as well as monojugate (single-spiral) phyllotaxis.

  11. Ohmic contacts prepared by annealing of indium

    International Nuclear Information System (INIS)

    Evaporated thin films of indium, deposited at room temperature onto n-GaAs, forms a Schottky barrier which, upon annealing above In's melting point, turns into an ohmic contact. Such a behavior has been interpreted as the result of the formation, at least locally, of a graded Ga/sub 1-x/ In/sub x/ A s heterojunction, the conductivity of which (in the 10/sup -6//10/sup -7/ Ω . cm/sup 2/ range) had been previously checked by Molecular Beam Epitaxy (MBE). During the time this work was in preparation, other authors have supported the idea that the junction was probably not graded but abrupt, suggestion which has also been confirmed by (MBE) recent results. Whatever the Ga/In profile within these non-alloyed structures is, it appears to us that their fabrication might be facilitated by a previous arsenic enrichment of the GaAs surface before in deposition, It can be noted that SPICER's group has recently shown that the obtention of large values for x(x>0.3) does in fact require an As-rich surface. The aim of the present work is to check such assessment by using two means of endogenic As enrichment of (100) Si doped GaAs samples. 1. a photoelectrochemical (PEC) technique, previously proposed by WOODALL et al., which consists in the illumination of GaAs substrates immersed in a 1:1 HCl : H/sub 2/O solution (HCl 6M) by photons of energy higher than the band-gap of this material; and 2. a combined anodic/thermal/etching process which involves first the growth of an anodic oxide layer on GaAs in an AGW medium, followed by an annealing of the structure and a final post-etching of the oxide in a 1:11 MeOH : HCl etchant

  12. Laser annealing of amorphous carbon films

    International Nuclear Information System (INIS)

    Amorphous (a-C) Carbon thin films were deposited, using pulsed laser deposition (PLD) with a Nd:YAG laser (1064 nm, 7 ns), from a pyrolytic graphite target, on silicon and refractory metal (Mo) substrates to a film thickness of 55, 400 and 500 nm. Samples were grown at RT and then annealed by a laser annealing technique, to reduce residual stress and induce a locally confined 'graphitization' process. The films were exposed to irradiation, in vacuum, by a Nd:YAG pulsed laser, operating at different wavelengths (VIS, N-UV) and increasing values of energy from 6-100 mJ/pulse. The thinner films were completely destroyed by N-UV laser treatment also at lower energies, owing to the almost direct propagation of heat to the Si substrate with melting and ruinous blistering effects. For thicker films the Raman micro-analysis evidenced the influence of laser treatments on the sp3/sp2 content evolution, and established the formation of aromatic nano-structures of average dimension 4.1-4.7 nm (derived from the ID/IG peak ratio), at fluence values round 50 mJ/cm2 for N-UV and 165 mJ/cm2 for VIS laser irradiation. Higher fluences were not suitable for a-Carbon 'graphitization', since a strong ablation process was the prominent effect of irradiation. Grazing incidence XRD (GI-XRD) used to evaluate the dimension and texturing of nano-particles confirmed the findings of Raman analysis. The effects of irradiation on surface morphology were studied by SEM analysis

  13. Influence of preliminary annealing on sound velocity in strained polymers

    International Nuclear Information System (INIS)

    Present article is devoted to influence of preliminary annealing on sound velocity in strained polymers. The dependence of sound velocity on loading duration in natural silk at 77 Mpa and different annealing duration was studied. The structural changes occurring in strained polymers at thermal treatment were considered.

  14. Parameters Optimization of Low Carbon Low Alloy Steel Annealing Process

    Institute of Scientific and Technical Information of China (English)

    Maoyu ZHAO; Qianwang CHEN

    2013-01-01

    A suitable match of annealing process parameters is critical for obtaining the fine microstructure of material.Low carbon low alloy steel (20CrMnTi) was heated for various durations near Ac temperature to obtain fine pearlite and ferrite grains.Annealing temperature and time were used as independent variables,and material property data were acquired by orthogonal experiment design under intercritical process followed by subcritical annealing process (IPSAP).The weights of plasticity (hardness,yield strength,section shrinkage and elongation) of annealed material were calculated by analytic hierarchy process,and then the process parameters were optimized by the grey theory system.The results observed by SEM images show that microstructure of optimization annealing material are consisted of smaller lamellar pearlites (ferrite-cementite)and refining ferrites which distribute uniformly.Morphologies on tension fracture surface of optimized annealing material indicate that the numbers of dimple fracture show more finer toughness obviously comparing with other annealing materials.Moreover,the yield strength value of optimization annealing material decreases apparently by tensile test.Thus,the new optimized strategy is accurate and feasible.

  15. Remote sensing of atmospheric duct parameters using simulated annealing

    Institute of Scientific and Technical Information of China (English)

    Zhao Xiao-Feng; Huang Si-Xun; Xiang Jie; Shi Wei-Lai

    2011-01-01

    Simulated annealing is one of the robust optimization schemes. Simulated annealing mimics the annealing process of the slow cooling of a heated metal to reach a stable minimum energy state. In this paper,we adopt simulated annealing to study the problem of the remote sensing of atmospheric duct parameters for two different geometries of propagation measurement. One is from a single emitter to an array of radio receivers (vertical measurements),and the other is from the radar clutter returns (horizontal measurements). Basic principles of simulated annealing and its applications to refractivity estimation are introduced. The performance of this method is validated using numerical experiments and field measurements collected at the East China Sea. The retrieved results demonstrate the feasibility of simulated annealing for near real-time atmospheric refractivity estimation. For comparison,the retrievals of the genetic algorithm are also presented. The comparisons indicate that the convergence speed of simulated annealing is faster than that of the genetic algorithm,while the anti-noise ability of the genetic algorithm is better than that of simulated annealing.

  16. Deformation and annealing response of TD-nickel chromium sheet

    Science.gov (United States)

    Kane, R. D.; Ebert, L. J.

    1973-01-01

    The deformation and annealing response of TD-nickel chromium (TD-NiCr) 0.1 inch thick sheet was examined using various cold-rolling and annealing treatments. Upon annealing (above 816 C (1500 F), the as-received material was converted from an initially ultra-fine grain size (average grain dimension 0.51 micron) to a large grain structure. Increases in grain size by a factor of 100 to 200 were observed for this transformation. However, in those material states where the large grain transformation was absent, a fine grain recrystallized structure formed upon annealing (above 732 C (1350 F)). The deformation and annealing response of TD-NiCr sheet was evaluated with respect to the processing related variables as mode and severity of deformation and annealing temperature. Results indicate that the large grain transformation, classical primary recrystallization occurs. Using selected materials produced during the deformation and annealing study, the elevated temperature tensile properties of TD-NiCr sheet were examined in the temperature range 593 C (1100 F) to 1093 C (2000 F). It was observed that the elevated temperature tensile properties of TD-NiCr sheet could be optimized by the stabilization of a large grain size in this material using the cold working and/or annealing treatments developed during the present investigation.

  17. Simulated Annealing for Location Area Planning in Cellular networks

    Directory of Open Access Journals (Sweden)

    N. B. Prajapati

    2010-03-01

    Full Text Available LA planning in cellular network is useful for minimizing location management cost in GSM network. Infact, size of LA can be optimized to create a balance between the LA update rate and expected pagingrate within LA. To get optimal result for LA planning in cellular network simulated annealing algorithmis used. Simulated annealing give optimal results in acceptable run-time.

  18. Simulated Annealing for Location Area Planning in Cellular networks

    OpenAIRE

    Prajapati, N. B.; R. R. Agravat; Hasan, M I

    2010-01-01

    LA planning in cellular network is useful for minimizing location management cost in GSM network. In fact, size of LA can be optimized to create a balance between the LA update rate and expected paging rate within LA. To get optimal result for LA planning in cellular network simulated annealing algorithm is used. Simulated annealing give optimal results in acceptable run-time.

  19. Superparamagnetic resonance of annealed iron-containing borate glass

    International Nuclear Information System (INIS)

    A lithium borate glass containing a small amount of iron oxide is studied by electron magnetic resonance at room temperature after repeated annealing steps between 460 and 670 deg. C. As the anneal temperature increases, the gef=4.3 sharp line characteristic of isolated iron ions decreases in intensity and finally disappears. Simultaneously, a narrow line emerges at gef approx. 2.0, superposed with a broader one, the narrow and the broader components predominating respectively after annealing at lower and at higher temperatures. Computer simulations of spectra have been carried out, based on a model of resonance of ferromagnetic single-domain nanoparticles randomly dispersed in the devitrified glass (superparamagnetic resonance). As the anneal temperature increases, the most probable particle diameter obtained assuming a log-normal distribution of diameters increases from 2.9 to 4.7 nm showing a saturation at higher anneal temperatures, whereas the relative number of larger particles grows continuously. (author)

  20. Mechanism of Annealing Softening of Rolled or Forged Tool Steel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to reduce hardness of rolled or forged steels after annealing and improve processability, the diameter and dispersity of carbides were measured by SEM and quantitative metallography. The microstructure of annealed steel was analyzed by TEM. The effects of the factors such as solute atoms, carbides, grain boundary and interphase boundary were studied. The mechanism of annealing softening of steels was analyzed on the examples of steels H13, S5, S7, X45CrNiMo4, which are treated with new technology. The results showed that the softening of H13, S7, S5 is easier obtained by isothermal or slow cooling annealing from slightly below A1, but hardness of X45CrNiMo4 after annealing is reduced effectively by obtaining coarse lamellar pearlite. Economic results can be obtained from good processability.

  1. Thermal annealing of GaAs concentrator solar cells

    Science.gov (United States)

    Curtis, H. B.; Brinker, David J.

    1991-01-01

    Isochronal and isothermal annealing tests were performed on GaAs concentrator cells which were irradiated with electrons of various energies to fluences up to 1 x 10(exp 16) e/sq cm. The results include: (1) For cells irradiated with electrons from 0.7 to 2.3 MeV, recovery decreases with increasing electron energy. (2) As determined by the un-annealed fractions, isothermal and isochronal annealing produce the same recovery. Also, cells irradiated to 3 x 10(exp 15) or 1 x 10(exp 16) e/sq cm recover to similar un-annealed fractions. (3) Some significant annealing is being seen at 150 C although very long times are required.

  2. Annealing effect on InP vertical porous arrays

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    InP vertical porous arrays were produced using electrochemical etching at room temperature.The as-etched InP samples were annealed in an ultra high vacuum camber.Cross-sectional analysis of the porous layer was conducted using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).Annealing in vacuum was found to meliorate the structural quality of the porous layer.EDX results showed the composition change of the porous InP.By controlling the annealing process parameters,the content ratio of phosphorus (P) to indium (In) is tuneable.Raman property of the samples was also investigated at room temperature.Compared with the sample without annealing treatment,Raman spectrum from the annealed sample showed red-shifted LO and TO peaks together with sharpened LO peak and shortened TO peak.

  3. Crystallization degree change of expanded graphite by milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Tang Qunwei [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China); Wu Jihuai [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China)], E-mail: jhwu@hqu.edu.cn; Sun Hui; Fang Shijun [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China)

    2009-05-05

    Expanded graphite was ball milled with a planetary mill in air atmosphere, and subsequently thermal annealed. The samples were characterized by using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). It was found that in the milling initial stage (less than 12 h), the crystallization degree of the expanded graphite declined gradually, but after milling more than 16 h, a recrystallization of the expanded graphite toke place, and ordered nanoscale expanded graphite was formed gradually. In the annealing initial stage, the non-crystallization of the graphite occurred, but, beyond an annealing time, recrystallizations of the graphite arise. Higher annealing temperature supported the recrystallization. The milled and annealed expanded graphite still preserved the crystalline structure as raw material and hold high thermal stability.

  4. Evolution of perpendicular magnetized tunnel junctions upon annealing

    Science.gov (United States)

    Devolder, Thibaut; Couet, S.; Swerts, J.; Furnemont, A.

    2016-04-01

    We study the evolution of perpendicularly magnetized tunnel junctions under 300 to 400 °C annealing. The hysteresis loops do not evolve much during annealing and they are not informative of the underlying structural evolutions. These evolutions are better revealed by the frequencies of the ferromagnetic resonance eigenmodes of the tunnel junction. Their modeling provides the exchange couplings and the layers' anisotropies within the stack which can serve as a diagnosis of the tunnel junction state after each annealing step. The anisotropies of the two CoFeB-based parts and the two Co/Pt-based parts of the tunnel junction decay at different rates during annealing. The ferromagnet exchange coupling through the texture-breaking Ta layer fails above 375 °C. The Ru spacer meant to promote a synthetic antiferromagnet behavior is also insufficiently robust to annealing. Based on these evolutions we propose optimization routes for the next generation tunnel junctions.

  5. Reaction kinetics of annealing of high energy implantation by XRD

    International Nuclear Information System (INIS)

    The annealing of structural defects caused by high energy implantation is studied using X-ray diffraction. The implanted sample (dose: 1 x 1014 ions/cm2) was isochronally annealed in flowing nitrogen in steps of 50 K up to 823 K for 10 min each, using a RTA system developed in Mumbai University. XRD patterns were recorded after each annealing and analyzed for strain and curvature. Also, the screw dislocation density was estimated at each stage of annealing using the FWHM of w scans in high resolution mode. The XRD profiles were simulated using the dynamical theory of X-ray diffraction for layer damage i.e. thickness, mismatch with respect to substrate, Debye Waller factor and sample curvature. The activation energy and characteristic temperature of annealing were estimated through reaction kinetics, utilizing the experimental XRD for progressive changes with temperature, of strain and dislocation density

  6. On the Debossing, Annealing and Mounting of Bells

    Science.gov (United States)

    PERRIN, R.; SWALLOWE, G. M.; CHARNLEY, T.; MARSHALL, C.

    1999-10-01

    Changes in the frequencies of the musical partials of various types of bells following debossing dismounting/mounting and annealing/quench annealing are reported. Debossing, dismounting and quench annealing lead to frequency drops, while mounting gives rises. Annealing can lead to frequency increases or decreases depending upon the maximum temperature employed and the initial residual stress. Qualitative explanations of these phenomena are given in terms of changes in crown stiffness, internal stress and alloy phase structure. These are supported by the results of X-ray diffraction measurements. Although the effects are all small they can be large enough to be detected by a reasonably musical car. This, together with the fact that the effects cannot be controlled, gives a plausible explanation of why modern bellfounders use vertical lathes for tuning, even with small carillon bells, and do not anneal bells when trying to control warble.

  7. Grain growth of gold nanowires through laser zone annealing and rapid thermal annealing

    Science.gov (United States)

    Kim, Jung Yun

    The grain boundary density in metals plays an increasingly important role as structures are shrinking down to dimensions comparable to the electronic mean free path. Metal nanowires prepared through electron beam lithography, electrodeposition and many other methods are nanocrystalline with an average grain diameter in the range of 2--50 nm. For these nanocrystalline metal nanowires with a lateral dimensions larger than the mean grain diameter, the electrical resistance is dominated by electron scattering at the grain boundaries as opposed to the external surfaces and the background. The deleterious effect of grain boundaries on the electrical properties provides strong motivation to develop post-processing methods for increasing the mean grain diameter. Thermal annealing has typically been used to induce grain growth. However, for metal nanowires patterned on a planar surface, a classic Rayleigh instability is observed resulting in decomposition of the nanowire to a periodic series of nanoparticles. In principle, grain growth requires short range motion of atoms while shape change requires mass displacement across large distances. Laser zone annealing was used to test whether the latter could be suppressed by rapidly heating a highly localized section of the wire followed by rapidly cooling. A piezoelectric motor was used to translate the wire at nanoscale steps over a 532 nm confocal laser source at range of power levels (2.5--10 mW) and translation rates (7--128 nm/s). Annealing at a laser power of 10 mW resulted in grain growth of nearly 300% from 27 nm to 85 nm. A second approach to inhibit shape change while allowing for grain growth was to encapsulate the nanowire with an alumina layer to constrict large scale atomic diffusion during isothermal annealing. The alumina coating maintained the shape of the nanowire up to a temperature of ˜669 K and grain growth approaching the limiting size was observed. To study the grain growth kinetics, in situ electrical

  8. Annealed Scaling for a Charged Polymer

    Science.gov (United States)

    Caravenna, F.; den Hollander, F.; Pétrélis, N.; Poisat, J.

    2016-03-01

    This paper studies an undirected polymer chain living on the one-dimensional integer lattice and carrying i.i.d. random charges. Each self-intersection of the polymer chain contributes to the interaction Hamiltonian an energy that is equal to the product of the charges of the two monomers that meet. The joint probability distribution for the polymer chain and the charges is given by the Gibbs distribution associated with the interaction Hamiltonian. The focus is on the annealed free energy per monomer in the limit as the length of the polymer chain tends to infinity. We derive a spectral representation for the free energy and use this to prove that there is a critical curve in the parameter plane of charge bias versus inverse temperature separating a ballistic phase from a subballistic phase. We show that the phase transition is first order. We prove large deviation principles for the laws of the empirical speed and the empirical charge, and derive a spectral representation for the associated rate functions. Interestingly, in both phases both rate functions exhibit flat pieces, which correspond to an inhomogeneous strategy for the polymer to realise a large deviation. The large deviation principles in turn lead to laws of large numbers and central limit theorems. We identify the scaling behaviour of the critical curve for small and for large charge bias. In addition, we identify the scaling behaviour of the free energy for small charge bias and small inverse temperature. Both are linked to an associated Sturm-Liouville eigenvalue problem. A key tool in our analysis is the Ray-Knight formula for the local times of the one-dimensional simple random walk. This formula is exploited to derive a closed form expression for the generating function of the annealed partition function, and for several related quantities. This expression in turn serves as the starting point for the derivation of the spectral representation for the free energy, and for the scaling theorems

  9. Annealed Scaling for a Charged Polymer

    Energy Technology Data Exchange (ETDEWEB)

    Caravenna, F., E-mail: francesco.caravenna@unimib.it [Università degli Studi di Milano-Bicocca, Dipartimento di Matematica e Applicazioni (Italy); Hollander, F. den, E-mail: denholla@math.leidenuniv.nl [Leiden University, Mathematical Institute (Netherlands); Pétrélis, N., E-mail: nicolas.petrelis@univ-nantes.fr [Université de Nantes, Laboratoire de Mathématiques Jean Leray UMR 6629 (France); Poisat, J., E-mail: poisat@ceremade.dauphine.fr [Université Paris-Dauphine, PSL Research University, CEREMADE, UMR 7534 (France)

    2016-03-15

    This paper studies an undirected polymer chain living on the one-dimensional integer lattice and carrying i.i.d. random charges. Each self-intersection of the polymer chain contributes to the interaction Hamiltonian an energy that is equal to the product of the charges of the two monomers that meet. The joint probability distribution for the polymer chain and the charges is given by the Gibbs distribution associated with the interaction Hamiltonian. The focus is on the annealed free energy per monomer in the limit as the length of the polymer chain tends to infinity. We derive a spectral representation for the free energy and use this to prove that there is a critical curve in the parameter plane of charge bias versus inverse temperature separating a ballistic phase from a subballistic phase. We show that the phase transition is first order. We prove large deviation principles for the laws of the empirical speed and the empirical charge, and derive a spectral representation for the associated rate functions. Interestingly, in both phases both rate functions exhibit flat pieces, which correspond to an inhomogeneous strategy for the polymer to realise a large deviation. The large deviation principles in turn lead to laws of large numbers and central limit theorems. We identify the scaling behaviour of the critical curve for small and for large charge bias. In addition, we identify the scaling behaviour of the free energy for small charge bias and small inverse temperature. Both are linked to an associated Sturm-Liouville eigenvalue problem. A key tool in our analysis is the Ray-Knight formula for the local times of the one-dimensional simple random walk. This formula is exploited to derive a closed form expression for the generating function of the annealed partition function, and for several related quantities. This expression in turn serves as the starting point for the derivation of the spectral representation for the free energy, and for the scaling theorems

  10. The changes of ADI structure during high temperature annealing

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2010-01-01

    Full Text Available The results of structure investigations of ADI during it was annealing at elevated temperature are presented. Ductile iron austempered at temperature 325oC was then isothermally annealed 360 minutes at temperature 400, 450, 500 and 550oC. The structure investigations showed that annealing at these temperatures caused substantial structure changes and thus essential hardness decrease, which is most useful property of ADI from point of view its practical application. Degradation advance of the structure depends mainly on annealing temperature, less on the time of the heat treatment. It was concluded that high temperature annealing caused precipitation of Fe3C type carbides, which morphology and distribution depend on temperature. In case of 400oC annealing the carbides precipitates inside bainitic ferrite lath in specific crystallographic planes and partly at the grain boundaries. The annealing at the temperature 550oC caused disappearing of characteristic for ADI needle or lath – like morphology, which is replaced with equiaxed grains. In this case Fe3C carbides take the form very fine precipitates with spheroidal geometry.

  11. Fabrication of onion-like carbon from nanodiamond by annealing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Onion-like carbon(OLC)was synthesized by annealing nanodiamond in low vacuum of 1 Pa and at annealing temperatures from 500℃to 1400℃.The high-resolution transmission electron microscope (HRTEM)images,X-ray diffraction(XRD)and Raman spectrum of the OLC showed that there was no OLC when the annealing temperature was lower than 900℃.Moreover,the fragment amorphous carbon existed on the surfaces of the nanodiamond particles.At the annealing temperature of 900℃,the OLC particles began appearing and the size of the OLC particles was smaller than 5 nm.When the annealing temperature was increased from 900℃to 1400℃,the nanodiamond was transformed into OLC gradu- ally.At the annealing temperature of 1400℃,all the nanodiamond particles were transformed into OLC completely.The OLC exhibited similarity to the original nanodiamond particles in shape.A mechanism for the OLC synthesis by annealing was provided.The graphitization started at the surfaces of the nanodiamond particles.The formation process of the OLC includes formation of graphite fragments, connection and curvature of graphite sheets between diamond(111)planes and closure of the graphite layers.

  12. Surface Morphology of Annealed Lead Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    P.Kalugasalam,

    2010-06-01

    Full Text Available The thin films of Lead Phthalocyanine (PbPc on glass substrates were prepared by Vacuum deposition. The thickness of the films was 450 nm. The sample annealed in high vacuum at 373 K temperature. The sample has been analysed by X-ray diffraction, scanning electron microscopy and atomic force microscopy in order to get structural and surface morphology of the PbPc thin film. The formation of XRD patterns of PbPc shows a triclinic grains (T seen along with monoclinic (M forms of PbPc. The sample is annealed at 373 K temperatures; the film shows peaks that assigned to the triclinic phase. SEM and AFM are the best tools to investigate the surface smoothness and to find the grain size of the particles. The grain size is calculated for all films of different thicknesses. The annealed AFM micrograph shows that the surface of the films consists of large holes. The annealed AFM image indicates a smooth surface. It is very clear that the grain size decreases with increase in the annealing temperature. The roughness also decreases with the increase in film annealing temperature. Annealed film leads to the oxidation of the hthalocyanine with oxygen absorbed or diffused. Therefore, the heat is responsible for the increase in film thickness. Since the films expand, it is believed that the porosity is increased.

  13. Extrapolation of zircon fission-track annealing models

    International Nuclear Information System (INIS)

    One of the purposes of this study is to give further constraints on the temperature range of the zircon partial annealing zone over a geological time scale using data from borehole zircon samples, which have experienced stable temperatures for ∼1 Ma. In this way, the extrapolation problem is explicitly addressed by fitting the zircon annealing models with geological timescale data. Several empirical model formulations have been proposed to perform these calibrations and have been compared in this work. The basic form proposed for annealing models is the Arrhenius-type model. There are other annealing models, that are based on the same general formulation. These empirical model equations have been preferred due to the great number of phenomena from track formation to chemical etching that are not well understood. However, there are two other models, which try to establish a direct correlation between their parameters and the related phenomena. To compare the response of the different annealing models, thermal indexes, such as closure temperature, total annealing temperature and the partial annealing zone, have been calculated and compared with field evidence. After comparing the different models, it was concluded that the fanning curvilinear models yield the best agreement between predicted index temperatures and field evidence. - Highlights: ► Geological data were used along with lab data for improving model extrapolation. ► Index temperatures were simulated for testing model extrapolation. ► Curvilinear Arrhenius models produced better geological temperature predictions

  14. Embrittlement recovery due to annealing of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Eason, E.D.; Wright, J.E.; Nelson, E.E. [Modeling and Computing Services, Boulder, CO (United States); Odette, G.R.; Mader, E.V. [Univ. of California, Santa Barbara, CA (United States)

    1996-03-01

    Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

  15. Embrittlement recovery due to annealing of reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes

  16. The phase diagram of annealed Ge(111)/Ga

    DEFF Research Database (Denmark)

    Molinàs-Mata, P.; Böhringer, M.; Artacho, E.;

    1995-01-01

    A study of the annealed phases of Ge(111)/Ga for coverages above 0.05 ML is presented. The surfaces are investigated by low-energy electron diffraction, scanning tunneling microscopy, and partly by photoemission and surface X-ray diffraction using synchrotron radiation. For Ga coverages beyond 0.......05 ML and up to about 2 ML and annealing temperatures higher than 500 degrees C four different phases appear. They all can be characterized as being discommensurate. Surprisingly, no commensurate superstructure appears on annealed Ge(111)/Ga....

  17. Annealing properties of potato starches with different degrees of phosphorylation

    DEFF Research Database (Denmark)

    Muhrbeck, Per; Svensson, E

    1996-01-01

    Changes in the gelatinization temperature interval and gelatinization enthalpy with annealing time at 50 degrees C were followed for a number of potato starch samples, with different degrees of phosphorylation, using differential scanning calorimetry. The gelatinization temperature increased with...... the length of the annealing time up to the maximum time of 1280 min and a clear relation to the degree of phosphorylation was observed. The gelatinization enthalpy changed very slowly during the initial period of annealing, but faster in the later stages of the process. The increase in enthalpy was...

  18. A NEW GENETIC SIMULATED ANNEALING ALGORITHM FOR FLOOD ROUTING MODEL

    Institute of Scientific and Technical Information of China (English)

    KANG Ling; WANG Cheng; JIANG Tie-bing

    2004-01-01

    In this paper, a new approach, the Genetic Simulated Annealing (GSA), was proposed for optimizing the parameters in the Muskingum routing model. By integrating the simulated annealing method into the genetic algorithm, the hybrid method could avoid some troubles of traditional methods, such as arduous trial-and-error procedure, premature convergence in genetic algorithm and search blindness in simulated annealing. The principle and implementing procedure of this algorithm were described. Numerical experiments show that the GSA can adjust the optimization population, prevent premature convergence and seek the global optimal result.Applications to the Nanyunhe River and Qingjiang River show that the proposed approach is of higher forecast accuracy and practicability.

  19. Spontaneous symmetry breaking in annealed and quenched gauge field models

    International Nuclear Information System (INIS)

    The structure of annealed and quenched models with local U(1) gauge invariance is studied in terms of the Helmholtz free energy. The first non-trivial, or one-loop, account of fluctuations in the annealed model suggests that spontaneous symmetry breaking occurs in two and three dimensions, through a first-order phase transition. Within the same approximation scheme, the quenched model displays a continuous phase transition. A more complete account of the fluctuations in the annealed model changes the nature of the transition to a continuous one, whereas spontaneous symmetry breaking is then absent with quenched disorder. (author)

  20. Flattening of micro-structured Si surfaces by hydrogen annealing

    International Nuclear Information System (INIS)

    We report atomic scale flattening of surfaces of microstructures formed on Si wafers by furnace annealing. To avoid thermal deformation of the fabricated structures, advantage was taken of hydrogen annealing, which enables us to decrease the relaxation rate of Si surfaces due to surface hydrogenation. We examined cross-sectional shape and sidewall morphology of 3 μm deep trenches on Si(0 0 1) substrates after annealing at 1000 deg. Cunder various H2 pressures of 40-760 Torr. We successfully formed Si trenches with flat surfaces composed of terraces and steps while preserving the designed trench profile by increasing H2 pressure to 760 Torr

  1. Excimer laser annealing for low-voltage power MOSFET

    Science.gov (United States)

    Chen, Yi; Okada, Tatsuya; Noguchi, Takashi; Mazzamuto, Fulvio; Huet, Karim

    2016-08-01

    Excimer laser annealing of lumped beam was performed to form the P-base junction for high-performance low-voltage-power MOSFET. An equivalent shallow-junction structure for the P-base junction with a uniform impurity distribution is realized by adopting excimer laser annealing (ELA). The impurity distribution in the P-base junction can be controlled precisely by the irradiated pulse energy density and the number of shots of excimer laser. High impurity activation for the shallow junction has been confirmed in the melted phase. The application of the laser annealing technology in the fabrication process of a practical low-voltage trench gate MOSFET was also examined.

  2. Interpretation of microstructure evolution during self-annealing and thermal annealing of nanocrystalline electrodeposits—A comparative study

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2010-01-01

    nickel electrodeposits was achieved by time-resolved X-ray diffraction line profile analysis and crystallographic texture analysis during room temperature storage and during isothermal annealing at elevated temperatures. These in-situ studies with unique time resolution allowed quantification of the self-annealing...... kinetics of copper and silver electrodeposits as well as the annealing kinetics of electrodeposited nickel. Similarities and characteristic differences of the kinetics and mechanisms of microstructure evolution in the various electrodeposits are discussed and the experimental results are attempted to be...

  3. Simulated quantum annealing of double-well and multiwell potentials.

    Science.gov (United States)

    Inack, E M; Pilati, S

    2015-11-01

    We analyze the performance of quantum annealing as a heuristic optimization method to find the absolute minimum of various continuous models, including landscapes with only two wells and also models with many competing minima and with disorder. The simulations performed using a projective quantum Monte Carlo (QMC) algorithm are compared with those based on the finite-temperature path-integral QMC technique and with classical annealing. We show that the projective QMC algorithm is more efficient than the finite-temperature QMC technique, and that both are inferior to classical annealing if this is performed with appropriate long-range moves. However, as the difficulty of the optimization problem increases, classical annealing loses efficiency, while the projective QMC algorithm keeps stable performance and is finally the most effective optimization tool. We discuss the implications of our results for the outstanding problem of testing the efficiency of adiabatic quantum computers using stochastic simulations performed on classical computers. PMID:26651813

  4. Microstructural characterization and impact toughness of intercritically annealed PM steels

    International Nuclear Information System (INIS)

    In this study, atomized iron powder (Ancorsteel 1000) was mixed with 0.3 and 0.5 wt.% graphite powder. After sintering at 1120 deg. C, coarse and fine ferrite and martensite (dual phase) microstructures were produced through intercritical annealing heat treatment at different temperatures. Specimens with various martensite volume fraction and size were impact tested. Impact toughness increased with increasing martensite volume fraction and decreasing martensite size. It was also seen that the impact toughness of specimens with 0.3 wt.% graphite was higher than those specimens with 0.5 wt.% graphite. Furthermore, the impact toughness of intercritically annealed specimens with fine ferrite and martensite microstructure was compared with a specimen that was conventionally quenched and tempered after sintering. The results showed that especially for high intercritical annealing temperatures, the impact toughness of intercritically annealed specimens was higher than that of conventionally heat-treated ones

  5. Synthesis of boron nitride nanotubes by boron ink annealing.

    Science.gov (United States)

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M

    2010-03-12

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs. PMID:20154372

  6. Some properties of laser annealed shallow As+ implanted silicon

    International Nuclear Information System (INIS)

    Studies have been made of shallow (proportional 150 A) As+-implanted silicon, with impurity concentrations that exceed the solid solubility limit. Under CW argon laser annealing conditions we have shown that the arsenic remains in the sample even if the surface of the silicon melts. Below the melt-threshold it is possible to select a laser power such that most of the implant radiation damage is annealed and the implant profile remains substantially unchanged. Increase of the laser power, still below the melt-threshold, does not significantly alter the quality of the annealed crystal but does cause a spreading of the profile of the impurity implants. The measured sheet resistance, for the given annealing conditions, is approximately twice the estimated value. (orig.)

  7. Compressive anneal processing (CAP) of Bi2223 superconducting tapes

    International Nuclear Information System (INIS)

    The conventional processing of oxide powder-in-tube Bi2223 superconductor tapes involves iterative cycles of mechanical deformation to develop texture and reduce porosity, followed by thermal annealing to react components, relieve stress and heal cracks. However, texture and deformation hardening and cracking may limit the ability to obtain the desired grain texture through deformation alone. In addition, desintering of the oxide core occurs during annealing. We have developed a compressive anneal processing (CAP) technique in which a continuous uniaxial pressure is applied during the annealing. The new process is found to promote texture formation, enhance reaction kinetics and prevent desintering and bloating. Our initial results show that the CAP technique significantly improves the critical current density. (author)

  8. Synthesis of boron nitride nanotubes by boron ink annealing

    International Nuclear Information System (INIS)

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

  9. Solvent vapor annealing of an insoluble molecular semiconductor

    KAUST Repository

    Amassian, Aram

    2010-01-01

    Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

  10. Precise annealing of focal plane arrays for optical detection

    Science.gov (United States)

    Bender, Daniel A.

    2015-09-22

    Precise annealing of identified defective regions of a Focal Plane Array ("FPA") (e.g., exclusive of non-defective regions of the FPA) facilitates removal of defects from an FPA that has been hybridized and/or packaged with readout electronics. Radiation is optionally applied under operating conditions, such as under cryogenic temperatures, such that performance of an FPA can be evaluated before, during, and after annealing without requiring thermal cycling.

  11. Hardening by annealing and softening by deformation in nanostructured metals

    DEFF Research Database (Denmark)

    Huang, X.; Hansen, N.; Tsuji, N.

    2006-01-01

    We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation-dislocation and....... As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing....

  12. Optimization by Quantum Annealing: Lessons from hard 3-SAT cases

    OpenAIRE

    Battaglia, Demian; Santoro, Giuseppe; Tosatti, Erio

    2005-01-01

    The Path Integral Monte Carlo simulated Quantum Annealing algorithm is applied to the optimization of a large hard instance of the Random 3-SAT Problem (N=10000). The dynamical behavior of the quantum and the classical annealing are compared, showing important qualitative differences in the way of exploring the complex energy landscape of the combinatorial optimization problem. At variance with the results obtained for the Ising spin glass and for the Traveling Salesman Problem, in the presen...

  13. Stochastic search in structural optimization - Genetic algorithms and simulated annealing

    Science.gov (United States)

    Hajela, Prabhat

    1993-01-01

    An account is given of illustrative applications of genetic algorithms and simulated annealing methods in structural optimization. The advantages of such stochastic search methods over traditional mathematical programming strategies are emphasized; it is noted that these methods offer a significantly higher probability of locating the global optimum in a multimodal design space. Both genetic-search and simulated annealing can be effectively used in problems with a mix of continuous, discrete, and integer design variables.

  14. An improved simulated annealing algorithm for standard cell placement

    Science.gov (United States)

    Jones, Mark; Banerjee, Prithviraj

    1988-01-01

    Simulated annealing is a general purpose Monte Carlo optimization technique that was applied to the problem of placing standard logic cells in a VLSI ship so that the total interconnection wire length is minimized. An improved standard cell placement algorithm that takes advantage of the performance enhancements that appear to come from parallelizing the uniprocessor simulated annealing algorithm is presented. An outline of this algorithm is given.

  15. Nonsmooth trajectory optimization - An approach using continuous simulated annealing

    Science.gov (United States)

    Lu, Ping; Khan, M. A.

    1993-01-01

    An account is given of the properties of a continuous simulated annealing algorithm that can function as a global optimization tool for nonsmooth dynamic systems, as shown in the case of a trajectory-optimization program implementation. The approach is shown to successfully solve the problem of nonsmooth trajectory optimization for a high performance rigid-body aircraft. The results obtained demonstrate the superiority of the simulated annealing algorithm over widely used algorithms.

  16. Implementation of a Simulated Annealing algorithm for Matlab

    OpenAIRE

    Moins, Stephane

    2002-01-01

    In this report we describe an adaptive simulated annealing method for sizing the devices in analog circuits. The motivation for use an adaptive simulated annealing method for analog circuit design are to increase the efficiency of the design circuit. To demonstrate the functionality and the performance of the approach, an operational transconductance amplifier is simulated. The circuit is modeled with symbolic equations that are derived automatically by a simulator.

  17. Influence of phosphate esters on the annealing properties of starch

    DEFF Research Database (Denmark)

    Wischmann, Bente; Muhrbeck, Per

    1998-01-01

    The effects of annealing on native potato, waxy maize, and phosphorylated waxy maize starches were compared. Phosphorylated waxy maize starch responded to annealing in a manner between that of the naturally phosphorylated potato starch and that of the native waxy maize starch. The gelatinisation ...... concluded that the phosphate groups have similar effects as they do in the native, naturally phosphorylated potato starch, although the substitution pattern is not entirely the same in the artificially phosphorylated starch....

  18. Intrinsic disorders and annealing metamict zircon as wave-guides

    International Nuclear Information System (INIS)

    The study of intrinsic disorders in zircon showed that at certain temperature during an annealing process, both Schottky and interstitial disorders would dominate the zircon structure. This time would be the best time to implant relative ions by diffusion, or directly to use an accelerator to implant these ions, then anneal the metamict zircon to tailor the characteristics of the zircon as wave-guides

  19. Thermal annealing of fission tracks in synthetic apatites

    OpenAIRE

    Carpena, J.; Lacout, Jean-Louis

    2010-01-01

    Synthetic analogues of poor-silicated natural apatites have been doped with uranium. These minerals have been irradiated with a thermal neutron dose in the aim to induce the 235U fission and to obtain a fission track population. Thermal annealing experiments have been performed on the fission track population and allow us to compare the ability of the synthetic minerals to anneal such nuclear damages with their natural analogues. The thermal of the fission tracks in the synthetic minerals nee...

  20. Optimization using quantum mechanics: quantum annealing through adiabatic evolution

    International Nuclear Information System (INIS)

    We review here some recent work in the field of quantum annealing, alias adiabatic quantum computation. The idea of quantum annealing is to perform optimization by a quantum adiabatic evolution which tracks the ground state of a suitable time-dependent Hamiltonian, where 'ℎ' is slowly switched off. We illustrate several applications of quantum annealing strategies, starting from textbook toy-models-double-well potentials and other one-dimensional examples, with and without disorder. These examples display in a clear way the crucial differences between classical and quantum annealing. We then discuss applications of quantum annealing to challenging hard optimization problems, such as the random Ising model, the travelling salesman problem and Boolean satisfiability problems. The techniques used to implement quantum annealing are either deterministic Schroedinger's evolutions, for the toy models, or path-integral Monte Carlo and Green's function Monte Carlo approaches, for the hard optimization problems. The crucial role played by disorder and the associated non-trivial Landau-Zener tunnelling phenomena is discussed and emphasized. (topical review)

  1. Degeneracy, degree, and heavy tails in quantum annealing

    Science.gov (United States)

    King, Andrew D.; Hoskinson, Emile; Lanting, Trevor; Andriyash, Evgeny; Amin, Mohammad H.

    2016-05-01

    Both simulated quantum annealing and physical quantum annealing have shown the emergence of "heavy tails" in their performance as optimizers: The total time needed to solve a set of random input instances is dominated by a small number of very hard instances. Classical simulated annealing, in contrast, does not show such heavy tails. Here we explore the origin of these heavy tails, which appear for inputs with high local degeneracy—large isoenergetic clusters of states in Hamming space. This category includes the low-precision Chimera-structured problems studied in recent benchmarking work comparing the D-Wave Two quantum annealing processor with simulated annealing. On similar inputs designed to suppress local degeneracy, performance of a quantum annealing processor on hard instances improves by orders of magnitude at the 512-qubit scale, while classical performance remains relatively unchanged. Simulations indicate that perturbative crossings are the primary factor contributing to these heavy tails, while sensitivity to Hamiltonian misspecification error plays a less significant role in this particular setting.

  2. Annealing characteristics of irradiated hydrogenated amorphous silicon solar cells

    Science.gov (United States)

    Payson, J. S.; Abdulaziz, S.; Li, Y.; Woodyard, J. R.

    1991-01-01

    It was shown that 1 MeV proton irradiation with fluences of 1.25E14 and 1.25E15/sq cm reduces the normalized I(sub SC) of a-Si:H solar cell. Solar cells recently fabricated showed superior radiation tolerance compared with cells fabricated four years ago; the improvement is probably due to the fact that the new cells are thinner and fabricated from improved materials. Room temperature annealing was observed for the first time in both new and old cells. New cells anneal at a faster rate than old cells for the same fluence. From the annealing work it is apparent that there are at least two types of defects and/or annealing mechanisms. One cell had improved I-V characteristics following irradiation as compared to the virgin cell. The work shows that the photothermal deflection spectroscopy (PDS) and annealing measurements may be used to predict the qualitative behavior of a-Si:H solar cells. It was anticipated that the modeling work will quantitatively link thin film measurements with solar cell properties. Quantitative predictions of the operation of a-Si:H solar cells in a space environment will require a knowledge of the defect creation mechanisms, defect structures, role of defects on degradation, and defect passivation and annealing mechanisms. The engineering data and knowledge base for justifying space flight testing of a-Si:H alloy based solar cells is being developed.

  3. Quantum versus simulated annealing in wireless interference network optimization

    Science.gov (United States)

    Wang, Chi; Chen, Huo; Jonckheere, Edmond

    2016-01-01

    Quantum annealing (QA) serves as a specialized optimizer that is able to solve many NP-hard problems and that is believed to have a theoretical advantage over simulated annealing (SA) via quantum tunneling. With the introduction of the D-Wave programmable quantum annealer, a considerable amount of effort has been devoted to detect and quantify quantum speedup. While the debate over speedup remains inconclusive as of now, instead of attempting to show general quantum advantage, here, we focus on a novel real-world application of D-Wave in wireless networking—more specifically, the scheduling of the activation of the air-links for maximum throughput subject to interference avoidance near network nodes. In addition, D-Wave implementation is made error insensitive by a novel Hamiltonian extra penalty weight adjustment that enlarges the gap and substantially reduces the occurrence of interference violations resulting from inevitable spin bias and coupling errors. The major result of this paper is that quantum annealing benefits more than simulated annealing from this gap expansion process, both in terms of ST99 speedup and network queue occupancy. It is the hope that this could become a real-word application niche where potential benefits of quantum annealing could be objectively assessed. PMID:27181056

  4. Quantum versus simulated annealing in wireless interference network optimization

    Science.gov (United States)

    Wang, Chi; Chen, Huo; Jonckheere, Edmond

    2016-05-01

    Quantum annealing (QA) serves as a specialized optimizer that is able to solve many NP-hard problems and that is believed to have a theoretical advantage over simulated annealing (SA) via quantum tunneling. With the introduction of the D-Wave programmable quantum annealer, a considerable amount of effort has been devoted to detect and quantify quantum speedup. While the debate over speedup remains inconclusive as of now, instead of attempting to show general quantum advantage, here, we focus on a novel real-world application of D-Wave in wireless networking—more specifically, the scheduling of the activation of the air-links for maximum throughput subject to interference avoidance near network nodes. In addition, D-Wave implementation is made error insensitive by a novel Hamiltonian extra penalty weight adjustment that enlarges the gap and substantially reduces the occurrence of interference violations resulting from inevitable spin bias and coupling errors. The major result of this paper is that quantum annealing benefits more than simulated annealing from this gap expansion process, both in terms of ST99 speedup and network queue occupancy. It is the hope that this could become a real-word application niche where potential benefits of quantum annealing could be objectively assessed.

  5. Spall Response of Annealed Copper to Direct Explosive Loading

    Science.gov (United States)

    Finnegan, Simon; Burns, Malcolm; Whiteman, Glenn

    2015-06-01

    Taylor wave spall experiments were conducted on annealed copper targets using direct explosive loading. The targets were mounted on the back of an explosive which was initiated using a gas gun plate impact. The explosive and target were separated by a layer of foam in order to reduce the peak amplitude and strain rate of the Taylor wave pulse. This technique creates a high stress state, with a lower strain rate than an equivalent plate impact experiment, within the target. An advantage of using a gas gun is that the explosive run to detonation following impact can be studied separately. Four shots were performed on two differently annealed batches of copper to investigate the effect of annealing on the spall response. One pair of targets was annealed at 1123 K for 4 hours and the other pair was annealed at 723 K for 1 hour. The free surface velocity profiles were recorded using a heterodyne velocimetry (HetV) probe, focussed on the centre of the target. To quantify the effect of the annealing the pullback shapes in the free surface velocity profiles and the calculated spall strengths were compared for the four targets.

  6. An approach for reactor vessel life assessment following an anneal

    International Nuclear Information System (INIS)

    The integrity of the reactor pressure vessel is critical to continued operation of nuclear power plants. Long term exposure to high energy neutrons can cause irradiation embrittlement of the reactor pressure vessel steel. Irradiation embrittlement may be a life limiting factor for some nuclear power plants. Annealing is the only option for reversing the effects of irradiation embrittlement. The feasibility and generic benefits of the annealing process have been demonstrated through numerous industry studies. The consideration of annealing as part of a reactor vessel aging management program requires the ability to predict the annealing and re-irradiation response of pressure vessel steel. Data for these predictions can be obtained through proper planning and implementation during the current years of reactor vessel operation. A comprehensive materials test plan enables a utility to gain significant information relative to reactor vessel annealing in a timely manner. This paper discusses a materials test plan for an example nuclear plant. The planning process, the type of data generated, and an approach for transforming the data into meaningful predictions for the vessel re-irradiation response are all illustrated. The intent is to provide guidelines for gathering and interpreting the data that is used to predict the life of a typical reactor vessel following an anneal

  7. Thermal, quantum and simulated quantum annealing: analytical comparisons for simple models

    OpenAIRE

    Bapst, Victor; Semerjian, Guilhem

    2015-01-01

    We study various annealing dynamics, both classical and quantum, for simple mean-field models and explain how to describe their behavior in the thermodynamic limit in terms of differential equations. In particular we emphasize the differences between quantum annealing (i.e. evolution with Schr\\"odinger equation) and simulated quantum annealing (i.e. annealing of a Quantum Monte Carlo simulation).

  8. Annealing behaviors of vacancy in varied neutron irradiated Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    CHEN Gui-feng; LI Yang-xian; LIU Li-li; NIU Ping-juan; NIU Sheng-li; CHEN Dong-feng

    2006-01-01

    The difference of annealing behaviors of vacancy-oxygen complex (VO) in varied dose neutron irradiated Czochralski silicon: (S1 5×1017 n/cm3 and S2 1.07×1019 n/cm3) were studied. The results show that the VO is one of the main defects formed in neutron irradiated Czochralski silicon (CZ-Si). In this defect,oxygen atom shares a vacancy,it is bonded to two silicon neighbors. Annealed at 200 ℃,divacancies are trapped by interstitial oxygen(Oi) to form V2O (840 cm-1). With the decrease of the 829 cm-1 (VO) three infrared absorption bands at 825 cm-1 (V2O2),834 cm-1 (V2O3) and 840 cm-1 (V2O) will rise after annealed at temperature range of 200-500 ℃. After annealed at 450-500 ℃ the main absorption bands in S1 sample are 834 cm-1,825 cm-1 and 889 cm-1 (VO2),in S2 is 825 cm-1. Annealing of A-center in varied neutron irradiated CZ-Si is suggested to consist of two processes. The first is due to trapping of VO by Oi in low dose neutron irradiated CZ-Si (S1) and the second is due to capture the wandering vacancy by VO,etc,in high dose neutron irradiated CZ-Si (S2),the VO2 plays an important role in the annealing of A-center. With the increase of the irradiation dose,the annealing behavior of A-center is changed.

  9. High efficient inverted polymer solar cells with different annealing treatment

    International Nuclear Information System (INIS)

    Inverted polymer solar cells (IPSCs) were fabricated with cesium carbonate (Cs2CO3) modified indium tin oxide (ITO) substrates as the electrode and molybdenum trioxide (MoO3) modified Al as the anode. The Cs2CO3 dissolved in 2-ethoxyethanol was spin-coated on ITO substrates, showing snowflake-like morphology characterized by the scanning electron microscope (SEM). The absorption, X-ray diffraction as well as the morphology of the active layer were measured before and after annealing treatment. The IPSCs with annealing treatments on the active layers and MoO3 layers exhibited the maximum power conversion efficiency (PCE) approaching to 2%, with open circuit voltage (Voc) of 0.57 V, short circuit current density (Jsc) of 8.8 mA/cm2 and fill factor (FF) of 38.7%. The performance of IPSCs was dramatically decreased by annealing treatment after the deposition of Al cathode, which may be due to the diffusion of Al atom crossing the MoO3 layer forming new channels for charge carrier collection. However, the new channels are not beneficial to the charge carrier collection, which is demonstrated from that the Jsc of IPSCs was evidently decreased from 8.8 to 4.6 mA/cm2 by annealing treatment after deposition Al layer. The annealing treatment after deposition of MoO3 could improve the interfacial contact to aid in electron extraction. Highlights: ► PCE of inverted polymer solar cells (IPSc) with Cs2Co3 modified ITO as cathode and MoO3/Al as anode is approaching to 2%. ► The snowflake-like morphology of Cs2CO3 was investigated by SEM. ► The annealing treatment before deposition Al layer has positive effect on improvement of IPSCs performance. ► EDX results directly demonstrate the vertical phase separation of P3HT:PCBM induced by annealing treatment.

  10. As2S8 planar waveguide: refractive index changes following an annealing and irradiation and annealing cycle, and light propagation features

    Institute of Scientific and Technical Information of China (English)

    Zou Liner; Wang Gouri; Shen Yun; Chen Baoxue; Mamoru Iso

    2011-01-01

    The refractive index of as-evaporated amorphous semiconductor As2S8 film upon an annealing and saturation irradiation and annealing cycle is reversible.Upon successive treatment with annealing and non-saturation irradiation and further annealing,the refractive index of the as-evaporated amorphous semiconductor As2 S8 film reaches a maximum value and then its reversibility occurs upon annealing.The annealing of the amorphous semiconductor As2S8 films results in the stabilization of the structure through changes of the S-S bonds in the nearest environment,accompanied by a decrease of film thickness.The As2S8 planar waveguide after annealing (130 ℃)and saturation irradiation and annealing (130 ℃) shows a good propagation characteristic with ca.0.27 dB/cm low propagation loss of the 632.8 nm guided mode.

  11. Sintering out of intercrystalline creep voids during an intermediate annealing in creep exposure

    International Nuclear Information System (INIS)

    The possibility of creep void shrinkage by regenerative annealing due to diffusion or creep of the surrounding material is investigated. The results of creep tests with the austenitic steel X 8 CrNiMoNb 16 16 show that the regenerating effect depends on the annealing time, temperature and creep rate reached before annealing. At higher annealing temperatures and longer annealing time changes of microstructure lead to a decrease of ductility and of the remaining life. (orig.)

  12. An Overview of Approaches to Modernize Quantum Annealing Using Local Searches

    OpenAIRE

    Chancellor, Nicholas

    2016-01-01

    I describe how real quantum annealers may be used to perform local (in state space) searches around specified states, rather than the global searches traditionally implemented in the quantum annealing algorithm. The quantum annealing algorithm is an analogue of simulated annealing, a classical numerical technique which is now obsolete. Hence, I explore strategies to use an annealer in a way which takes advantage of modern classical optimization algorithms, and additionally should be less sens...

  13. Annealing-induced shape recovery in thin film metallic glass

    International Nuclear Information System (INIS)

    Highlights: • Annealing-induced shape recovery of thin film metallic glass is examined. • Shape recovery becomes obvious with increasing temperature and holding time. • Minimum roughness is obtained when annealed within supercooled liquid region. • The amount of free volume in the film plays a role for the shape recovery. • The numerical simulation confirms the shape recovery upon annealing. - Abstract: The shape recovery property of a sputtered Zr50.3Cu28.1Al14Ni7.6 (in at.%) thin film metallic glass upon heating is examined. Due to the surface tension-driven viscous flow, the shape of indentation appears to recover to different extents at various temperatures and holding times. It is found that a maximum of 59.8% indentation depth recovery is achieved after annealing within the supercooled liquid region (SCLR). The amount of free volume in the film is found to play a role in the recovery. Atomic force microscopy results reveal a decrease in film roughness to a minimum value within SCLR. To elucidate the experimentally observed shape recovery, a numerical modeling has been employed. It is evident that the depressed region caused by indentation is elevated after annealing

  14. Experimental quantum annealing: case study involving the graph isomorphism problem

    Science.gov (United States)

    Zick, Kenneth M.; Shehab, Omar; French, Matthew

    2015-06-01

    Quantum annealing is a proposed combinatorial optimization technique meant to exploit quantum mechanical effects such as tunneling and entanglement. Real-world quantum annealing-based solvers require a combination of annealing and classical pre- and post-processing; at this early stage, little is known about how to partition and optimize the processing. This article presents an experimental case study of quantum annealing and some of the factors involved in real-world solvers, using a 504-qubit D-Wave Two machine and the graph isomorphism problem. To illustrate the role of classical pre-processing, a compact Hamiltonian is presented that enables a reduced Ising model for each problem instance. On random N-vertex graphs, the median number of variables is reduced from N2 to fewer than N log2 N and solvable graph sizes increase from N = 5 to N = 13. Additionally, error correction via classical post-processing majority voting is evaluated. While the solution times are not competitive with classical approaches to graph isomorphism, the enhanced solver ultimately classified correctly every problem that was mapped to the processor and demonstrated clear advantages over the baseline approach. The results shed some light on the nature of real-world quantum annealing and the associated hybrid classical-quantum solvers.

  15. On simulated annealing phase transitions in phylogeny reconstruction.

    Science.gov (United States)

    Strobl, Maximilian A R; Barker, Daniel

    2016-08-01

    Phylogeny reconstruction with global criteria is NP-complete or NP-hard, hence in general requires a heuristic search. We investigate the powerful, physically inspired, general-purpose heuristic simulated annealing, applied to phylogeny reconstruction. Simulated annealing mimics the physical process of annealing, where a liquid is gently cooled to form a crystal. During the search, periods of elevated specific heat occur, analogous to physical phase transitions. These simulated annealing phase transitions play a crucial role in the outcome of the search. Nevertheless, they have received comparably little attention, for phylogeny or other optimisation problems. We analyse simulated annealing phase transitions during searches for the optimal phylogenetic tree for 34 real-world multiple alignments. In the same way in which melting temperatures differ between materials, we observe distinct specific heat profiles for each input file. We propose this reflects differences in the search landscape and can serve as a measure for problem difficulty and for suitability of the algorithm's parameters. We discuss application in algorithmic optimisation and as a diagnostic to assess parameterisation before computationally costly, large phylogeny reconstructions are launched. Whilst the focus here lies on phylogeny reconstruction under maximum parsimony, it is plausible that our results are more widely applicable to optimisation procedures in science and industry. PMID:27150349

  16. Graphene preparation by annealing of Co/SiC structure

    Energy Technology Data Exchange (ETDEWEB)

    Macháč, Petr, E-mail: petr.machac@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Cichoň, Stanislav [Department of Solid State Engineering, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Institute of Physics of the ASCR, v.v.i., Na Slovance 1999/2, 182 21 Prague 8 (Czech Republic); Mišková, Linda [Central Laboratories, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Vondráček, Martin [Institute of Physics of the ASCR, v.v.i., Na Slovance 1999/2, 182 21 Prague 8 (Czech Republic)

    2014-11-30

    Graphical abstract: - Highlights: • Low temperature preparation of graphene by the annealing of Co/SiC structures. • Influence of cooling rates on graphene parameters. • Analysis of graphene structure by Raman spectroscopy, Atomic Force Microscopy and X-ray Photoelectron Spectroscopy. • Exfoliation of graphene with help of PMMA, electrical parameters measurement. • Preparation of bi-layer graphene by the annealing at 850 °C for 10 s. - Abstract: This work is focused on graphene preparation using the segregation method with Co/SiC structure, the method being a viable low temperature synthesis approach. The graphene preparation was carried out with the cobalt layer of 300 nm thickness; the technological process is based on an optimization of parameters (temperature and duration) of annealing which is a crucial step of the synthesis. 850 °C as an annealing temperature and 10 s as an annealing duration have been found to be the most optimal. The prepared graphene is close to the bi-layer graphene structure with its parameters. Structural parameters of the prepared graphene were determined from spectra obtained by Raman spectroscopy.

  17. Graphene preparation by annealing of Co/SiC structure

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Low temperature preparation of graphene by the annealing of Co/SiC structures. • Influence of cooling rates on graphene parameters. • Analysis of graphene structure by Raman spectroscopy, Atomic Force Microscopy and X-ray Photoelectron Spectroscopy. • Exfoliation of graphene with help of PMMA, electrical parameters measurement. • Preparation of bi-layer graphene by the annealing at 850 °C for 10 s. - Abstract: This work is focused on graphene preparation using the segregation method with Co/SiC structure, the method being a viable low temperature synthesis approach. The graphene preparation was carried out with the cobalt layer of 300 nm thickness; the technological process is based on an optimization of parameters (temperature and duration) of annealing which is a crucial step of the synthesis. 850 °C as an annealing temperature and 10 s as an annealing duration have been found to be the most optimal. The prepared graphene is close to the bi-layer graphene structure with its parameters. Structural parameters of the prepared graphene were determined from spectra obtained by Raman spectroscopy

  18. High pressure annealing of Europium implanted GaN

    KAUST Repository

    Lorenz, K.

    2012-02-09

    GaN epilayers were implanted with Eu to fluences of 1×10^13 Eu/cm2 and 1×10^15 Eu/cm2. Post-implant thermal annealing was performed in ultra-high nitrogen pressures at temperatures up to 1450 ºC. For the lower fluence effective structural recovery of the crystal was observed for annealing at 1000 ºC while optical activation could be further improved at higher annealing temperatures. The higher fluence samples also reveal good optical activation; however, some residual implantation damage remains even for annealing at 1450 ºC which leads to a reduced incorporation of Eu on substitutional sites, a broadening of the Eu luminescence lines and to a strongly reduced fraction of optically active Eu ions. Possibilities for further optimization of implantation and annealing conditions are discussed.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  19. Radiation induced effects and annealing methods in fiberoptics and glasses

    International Nuclear Information System (INIS)

    Radiation induced effects in glass-rods and fiberoptics have been studied to determine parameters affecting the application of these materials in nuclear technology, i.e. as fiberscopes for visual inspection in severe radiation environments. Different glass and fibertypes have been exposed to fission product gamma radiation. The radiation induced transmission loss was measured with a spectrophotometer and then different annealing methods were examined to improve the transmission properties again. Especially the changes in glass and fiber recovery vs. time as a function of radiation dose and annealing temperature were investigated. Annealing experiments were performed exposing the samples either to temperature treatment or to various light sources such as quartz lamp, arc lamp or UV-laser for optical annealing. The transmission recovery was then investigated either as a function of annealing temperature or of exposure time to the light sources. The results allow conclusions on the design and composition of optical fiber endoscopes to be used in severe radiation environment where image transmission is required in the presence of high level nuclear radiation. (author)

  20. Nanomechanical characteristics of annealed Si/SiGe superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ming-Jhang [Department of Mechanical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China); Wen, Hua-Chiang, E-mail: a091316104@gmail.com [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Wu, Shyh-Chi [Department of Mechanical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China); Chung Shan Institute of Science and Technology, CSIST, Taoyuan 325, Taiwan (China); Yang, Ping-Feng; Lai, Yi-Shao [Central Labs, Advanced Semiconductor Engineering, Inc., 26 Chin 3rd Rd., Nantze Export Processing Zone, 811 Nantze, Kaohsiung, Taiwan (China); Hsu, Wen-Kuang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Wu, Wen-Fa [National Nano Device Laboratories, Hsinchu 300, Taiwan (China); Chou, Chang-Pin [Department of Mechanical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China)

    2011-08-15

    In this study, the nanomechanical damage was investigated on the annealed Si/SiGe strained-layer superlattices (SLSs) deposited using an ultrahigh-vacuum chemical vapor deposition (UHVCVD). Nanoscratch, nanoindenter, atomic force microscopy (AFM), and transmission electron microscopy (TEM) techniques were used to determine the nanomechanical behavior of the SiGe films. With a constant force applied, greater hardness number and larger coefficients of friction ({mu}) were observed on the samples that had been annealed at 600 {sup o}C, suggesting that annealing of the Si/SiGe SLSs can induce greater shear resistance. AFM morphological studies of the Si/SiGe SLSs revealed that pile-up phenomena occurred on both sides of each scratch, with the formation of some pellets and microparticles. The Si/SiGe SLSs that had been subjected to annealing under various conditions exhibited significantly different features in their indentation results. Indeed, the TEM images reveal slight dislocation propagation in the microstructures. Thus, the hardness and elastic modulus can be increased slightly after annealing treatment because the existence of comparatively unstable microstructures. It is suggested that cracking phenomena dominate the damage cause of Si/SiGe SLSs.

  1. Microstructural evolution of oxygen implanted silicon during annealing processes

    International Nuclear Information System (INIS)

    Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS) have been employed to characterize the microstructures, oxygen distributions, and chemical bonding states of SIMOX (Separation by IMplanted OXygen) wafers. Silicon substrates were implanted at 550 deg. C with 2x1017 and 4x1017 cm-2 180 keV oxygen ions, followed by annealing at various temperatures. EELS spectra indicated that the chemical bonding state between Si and oxygen changed at 1000 deg. C anneal, though there was no appreciable change in the microstructures observed by TEM below 1000 deg. C anneal. Above 1100 deg. C, oxygen precipitates were preferentially formed around the peak positions of the defect and oxygen concentrations in the as-implanted samples. These precipitates aggregated to reduce the surface energy, and their size increased with temperature. After 1350 deg. C anneal, a continuous buried oxide layer was formed in the higher-dose specimen, while the upper- and lower-precipitates remained separately in the lower-dose one. The XPS profiles did not change at the later stage of annealing processes in the 2 x 1017 cm-2 sample, though the precipitates became larger in size. This suggests that the oxygen diffusion mostly occurs along the lateral direction but does not along the vertical one in this sample

  2. Toward understanding dynamic annealing processes in irradiated ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Michael Thomas [Texas A & M Univ., College Station, TX (United States)

    2013-05-01

    High energy particle irradiation inevitably generates defects in solids. The ballistic formation and thermalization of the defect creation process occur rapidly, and are believed to be reasonably well understood. However, knowledge of the evolution of defects after damage cascade thermalization, referred to as dynamic annealing, is quite limited. Unraveling the mechanisms associated with dynamic annealing is crucial since such processes play an important role in the formation of stable postirradiation disorder in ion-beam-processing of semiconductors, and determines the “radiation tolerance” of many nuclear materials. The purpose of this dissertation is to further our understanding of the processes involved in dynamic annealing. In order to achieve this, two main tasks are undertaken.

  3. Simulated annealing optimization for multi-objective economic dispatch solution

    Directory of Open Access Journals (Sweden)

    Ismail ZIANE

    2014-11-01

    Full Text Available This paper presents a multi-objective Simulated Annealing Optimization to solve a Dynamic Generation Dispatch problem. In this work, the problem is formulated as a multi-objective one with two competing functions, namely economic cost and emission functions, subject to different constraints. The inequality constraints considered are the generating unit capacity limits while the equality constraint is generation-demand balance. To show the advantages of the proposed algorithm, it has been applied for solving multi-objective EELD problems in a 3-generator system with NOx and SO2 emission. Results obtained with Simulated Annealing have been compared with other existing relevant approaches available in literatures. Experimental results show a proficiency of Simulated Annealing over other existing techniques in terms of robustness.

  4. Sub-critical annealing of cold worked steel

    International Nuclear Information System (INIS)

    The kinetics of annealing of eutectoid steel which was cold rolled 75% and annealed at each of 400, 500 and 6000C have been followed with measurements of microhardness, X-ray textures and line broadening, scanning and transmission electron microscopy and positron annihilation. The controlling process appears to be the diffusion of Fe along Fe3C- αFe interfaces. The polygonization of ferrite, the formation of recrystallized ferrite grains and the spheroidization of Fe3C all were observed. Major changes in positron and X-ray line breadth parameters within the first 10 to 100 seconds indicate very rapid initial recovery but it is not clear if subsequent changes in those two parameters are solely due to recrystallization or to overlapping recovery and recrystallization processes. Although some degree of spheroidization was involved in all of our anneals, the positron and X-ray line broadening were selective in that they see only changes in the ferrite

  5. Solving the Optimal Trading Trajectory Problem Using a Quantum Annealer

    Science.gov (United States)

    Rosenberg, Gili; Haghnegahdar, Poya; Goddard, Phil; Carr, Peter; Wu, Kesheng; de Prado, Marcos Lopez

    2016-09-01

    We solve a multi-period portfolio optimization problem using D-Wave Systems' quantum annealer. We derive a formulation of the problem, discuss several possible integer encoding schemes, and present numerical examples that show high success rates. The formulation incorporates transaction costs (including permanent and temporary market impact), and, significantly, the solution does not require the inversion of a covariance matrix. The discrete multi-period portfolio optimization problem we solve is significantly harder than the continuous variable problem. We present insight into how results may be improved using suitable software enhancements, and why current quantum annealing technology limits the size of problem that can be successfully solved today. The formulation presented is specifically designed to be scalable, with the expectation that as quantum annealing technology improves, larger problems will be solvable using the same techniques.

  6. A Personified Annealing Algorithm for Circles Packing Problem

    Institute of Scientific and Technical Information of China (English)

    ZHANGDe-Fu; LIXin

    2005-01-01

    Circles packing problem is an NP-hard problem and is difficult to solve. In this paper, a hybrid search strategy for circles packing problem is discussed. A way of generating new configuration is presented by simulating the moving of elastic objects, which can avoid the blindness of simulated annealing search and make iteration process converge fast. Inspired by the life experiences of people,an effective personified strategy to jump out of local minima is given. Based on the simulated annealing idea and personification strategy, an effective personified annealing algorithm for circles packing problem is developed. Numerical experiments on benchmark problem instances show that the proposed algorithm outperforms the best algorithm in the literature.

  7. SIMULATED ANNEALING BASED POLYNOMIAL TIME QOS ROUTING ALGORITHM FOR MANETS

    Institute of Scientific and Technical Information of China (English)

    Liu Lianggui; Feng Guangzeng

    2006-01-01

    Multi-constrained Quality-of-Service (QoS) routing is a big challenge for Mobile Ad hoc Networks (MANETs) where the topology may change constantly. In this paper a novel QoS Routing Algorithm based on Simulated Annealing (SA_RA) is proposed. This algorithm first uses an energy function to translate multiple QoS weights into a single mixed metric and then seeks to find a feasible path by simulated annealing. The paper outlines simulated annealing algorithm and analyzes the problems met when we apply it to Qos Routing (QoSR) in MANETs. Theoretical analysis and experiment results demonstrate that the proposed method is an effective approximation algorithms showing better performance than the other pertinent algorithm in seeking the (approximate) optimal configuration within a period of polynomial time.

  8. Flash memory ionizing radiation effects and annealing characteristics

    International Nuclear Information System (INIS)

    Background: Studies of the radiation effects on the floating-gate flash memory have been mainly focused on functionality measurement. Purpose: According to the present situation, flash memory was irradiated and annealed by 60Co γ rays, and the TID failure mechanism of the device was analyzed. Methods: The function parameters including DC and AC were measured using a large scale integrated circuit testing system. The range of radiation-sensitive parameters was extended using the Verigy 93000 instrument and the Shmoo test. Results: The results showed that the maximum operating frequency was radiation-sensitive parameter which has a significant change in radiation and annealing. Conclusions: Under strong electric field, due to the accumulation of oxide trapped charge and interface trap charge, the performance of charge pump circuit was deteriorated and the function of device was failed. Annealing characteristics indicated that the oxide trapped charge accounts for a major role. (authors)

  9. Thermally induced native defect transform in annealed GaSb

    Science.gov (United States)

    Jie, Su; Tong, Liu; Jing-Ming, Liu; Jun, Yang; Yong-Biao, Bai; Gui-Ying, Shen; Zhi-Yuan, Dong; Fang-Fang, Wang; You-Wen, Zhao

    2016-07-01

    Undoped p-type GaSb single crystals were annealed at 550–600 °C for 100 h in ambient antimony. The annealed GaSb samples were investigated by Hall effect measurement, glow discharge mass spectroscopy (GDMS), infrared (IR) optical transmission and photoluminescence (PL) spectroscopy. Compared with the as-grown GaSb single crystal, the annealed GaSb samples have lower hole concentrations and weak native acceptor related PL peaks, indicating the reduction of the concentration of gallium antisite related native acceptor defects. Consequently, the below gap infrared transmission of the GaSb samples is enhanced after the thermal treatment. The mechanism about the reduction of the native defect concentration and its influence on the material property were discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 61474104 and 61504131).

  10. Annealing of drawing grade steel coils at bell type furnaces

    International Nuclear Information System (INIS)

    Low carbon steel sheets are produced up to 0.5 mm thickness at Pakistan Steel. These sheets are used for different forming operations to produce auto parts, household appliances, car bodies etc. For such application the metal must have high ductility, good forming properties and low yield strength. Hot band from 2-3 mm thickness is cold reduced up to 0.5 mm thickness at reversible cold rolling mill. Then annealed in bell type furnaces with inner height of 4.7 meters, where coils are heated up to lower critical line in controlled atmosphere of nitrogen and hydrogen. The material may fail during subsequent forming operation if the annealing regime at the bell type furnaces is not optimum. Objective of the work undertaken is to produce sheet of good shape up to 0.3 mm thickness and evaluate annealing regime to have intended forming properties. (author)

  11. Temperature distribution in graphite during annealing in air cooled reactors

    International Nuclear Information System (INIS)

    A model for the evaluation temperature distributions in graphite during annealing operation in graphite. Moderated an-cooled reactors, is presented. One single channel and one dimension for air and graphite were considered. A numerical method based on finite control volumes was used for partioning the mathematical equations. The problem solution involves the use of unsteady equations of mass, momentum and energy conservation for air, and energy conservation for graphite. The source term was considered as stored energy release during annealing for describing energy conservation in the graphite. The coupling of energy conservation equations in air and graphite is performed by the heat transfer term betwen air and graphite. The results agree with experimental data. A sensitivity analysis shown that the termal conductivity of graphite and the maximum inlet channel temperature have great effect on the maximum temperature reached in graphite during the annealing. (author)

  12. Coordination Hydrothermal Interconnection Java-Bali Using Simulated Annealing

    Science.gov (United States)

    Wicaksono, B.; Abdullah, A. G.; Saputra, W. S.

    2016-04-01

    Hydrothermal power plant coordination aims to minimize the total cost of operating system that is represented by fuel costand constraints during optimization. To perform the optimization, there are several methods that can be used. Simulated Annealing (SA) is a method that can be used to solve the optimization problems. This method was inspired by annealing or cooling process in the manufacture of materials composed of crystals. The basic principle of hydrothermal power plant coordination includes the use of hydro power plants to support basic load while thermal power plants were used to support the remaining load. This study used two hydro power plant units and six thermal power plant units with 25 buses by calculating transmission losses and considering power limits in each power plant unit aided by MATLAB software during the process. Hydrothermal power plant coordination using simulated annealing plants showed that a total cost of generation for 24 hours is 13,288,508.01.

  13. Rapid Thermal annealing of silicon layers amorphized by ion implantation

    International Nuclear Information System (INIS)

    The recrystallization behavior and the supression mechanisms of the residual defects of silicon layers amorphized by ion implantation, were investigated. The samples were annealed with the aid of a rapid thermal annealing (RTA) system at temperature range from 850 to 12000C, and annealing time up to 120 s. Random and aligned Rutherford backscattering spectroscopy were used to analyse the samples. Similarities in the recrystallization behavior for layers implanted with ions of the same chemical groups such as As or Sb; Ge, Sn or Pb, In or Ga, are observed. The results show that the effective supression of resisual defects of the recrystallired layers is vinculated to the redistribution of impurities via thermal diffusion. (author)

  14. Molecular dynamics simulation of annealed ZnO surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Min, Tjun Kit; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    The effect of thermally annealing a slab of wurtzite ZnO, terminated by two surfaces, (0001) (which is oxygen-terminated) and (0001{sup ¯}) (which is Zn-terminated), is investigated via molecular dynamics simulation by using reactive force field (ReaxFF). We found that upon heating beyond a threshold temperature of ∼700 K, surface oxygen atoms begin to sublimate from the (0001) surface. The ratio of oxygen leaving the surface at a given temperature increases as the heating temperature increases. A range of phenomena occurring at the atomic level on the (0001) surface has also been explored, such as formation of oxygen dimers on the surface and evolution of partial charge distribution in the slab during the annealing process. It was found that the partial charge distribution as a function of the depth from the surface undergoes a qualitative change when the annealing temperature is above the threshold temperature.

  15. Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    Li Jinhua

    2004-01-01

    Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.

  16. Microstructural evolution in annealed and crept silicon nitride

    International Nuclear Information System (INIS)

    The microstructure of a commercial sintered silicon nitride has been examined in the as-sintered condition, after annealing to a stable microstructure in either air or argon, and after creep deformation. Both as-sintered material and material annealed to a stable microstructure were crept. Extensive analytical electron microscopy has been used to determine the composition of the intergranular material (amorphous and crystalline). The as-sintered material contains an amorphous intergranular phase which partially devitrifies upon exposure to high temperatures. The residual intergranular glass is homogeneous throughout the samples (even though different crystalline products form near the surface and in the center of samples annealed in air) and stable. Creep deformation does not affect the microstructural evolution. It is, however, responsible for internal strain and some cavitation in the material

  17. The isochronal annealing of irradiated n-channel power VDMOSFETs

    Science.gov (United States)

    Ristić, Goran S.; Andjelković, Marko; Savović, Svetislav

    2016-01-01

    The threshold voltage, VT , as well as threshold voltage shift, ΔVT , and its components, the component of threshold voltage shift due to radiation-induced fixed traps in the oxide, ΔVft , and the component of threshold voltage shift due to radiation-induced switching traps near and at gate oxide/substrate interface, ΔVst , are investigated, and fitted very well. The behavior of unannealed fraction of fixed traps during isochronal annealing is also considered. The proposed model describes unannealed fraction very well, and allows the prediction of fixed traps behavior at higher temperature. The number of defect types that are observably active during an isochronal temperature range could be found by this model, showing that isochronal annealing is competitive with isothermal annealing, which is widely used, but much more time consuming.

  18. Thin boron nitride nanotubes formed during annealing in ammonia gas

    International Nuclear Information System (INIS)

    Full text: We present a mechano-thermal process to synthesis thin boron nitride nanotubes of diameter around 7 nanometers. They were produced by mechanical milling of amorphous boron powder at ambient temperature, followed by thermal annealing in ammonia gas. High energy ball milling creates a precursor containing a high density of nanocrystalline BN seeds and fine particles of metal catalyst. Nanotubes grow out from the milled boron powder during subsequent annealing. The novelty of this approach lies in the formation of the thin BN nanotubes by annealing in ammonia gas instead of nitrogen gas. The boron nitride nanotubes produced have a well-defined crystalline structure and there is no iron within them. If nitrogen gas is used, thicker nanotubes of diameter in the range of 20-100 nm were obtained and iron was more likely to be found inside the nanotubes. Copyright (2005) Australian Institute of Physics

  19. Incoherent-light-flash annealing of phosphorus-implanted silicon

    International Nuclear Information System (INIS)

    Incoherent light pulses emitted from a xenon flash lamp were used to anneal radiation damage in (100) silicon implanted with 2 x 101531P+/cm2 at 100 keV. Electrical carrier concentration has been determined by means of differential sheet resistivity and Hall effect together with the anodic oxidation stripping technique; the surface photovoltage technique has been used to evaluate bulk lifetime and Rutherford backscattering and transmission electron microscopy for analysis of radiation damage. Damage recovery appears to take place via a solid phase epitaxial process. Electrical activity and carrier mobility values of samples annealed by incoherent light are similar to those obtained by laser, electron beam, and furnace annealing. The bulk lifetime of minority carriers is not degraded

  20. NRC assessment of the Department of Energy annealing demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, D.A.; Malik, S.N. [Nuclear Regulatory Commission, Washington, DC (United States)

    1997-02-01

    Thermal annealing is the only known method for mitigating the effects of neutron irradiation embrittlement in reactor pressure vessel (RPV) steels. In May 1996, the US Department of Energy (DOE) in conjunction with the American Society of Mechanical Engineers, Westinghouse, Cooperheat, Electric Power Research Institute (with participating utilities), Westinghouse Owner`s Group, Consumers Power, Electricite` de France, Duquesne Light and the Central Research Institute of the Electric Power Industry (Japan) sponsored an annealing demonstration project (ADP) at Marble Hill. The Marble Hill Plant, located in Madison, Indiana, is a Westinghouse 4 loop design. The plant was nearly 70% completed when the project was canceled. Hence, the RPV was never irradiated. The paper will present highlights from the NRCs independent evaluation of the Marble Hill Annealing Demonstration Project.

  1. Influence of laser annealing on SiOx films properties

    Science.gov (United States)

    Gavrylyuk, O. O.; Semchuk, O. Yu.; Steblova, O. V.; Evtukh, A. A.; Fedorenko, L. L.; Bratus, O. L.; Zlobin, S. O.; Karlsteen, M.

    2015-05-01

    The interaction of laser irradiation with SiOx films, and the process of decomposition of SiOx on SiO2 and Si nanocrystals under the influence of laser irradiation are investigated. The mathematical modeling of temperature distribution in a c-Si wafer as well as on its surface is carried out. It is shown that laser pulses can efficiently heat up the samples of crystalline silicon. Using multi-pulse procedure, the temperature necessary for annealing can be achieved with lower intensity of laser irradiation. Experimental investigations of laser-annealed SiOx films allowed determining their transformation with the formation of nanoislands. It was concluded that the surface topology, dielectric matrix structure, and electrical conductivity depend on laser beam intensity during the annealing process.

  2. Reduction of Annealing Times for Energy Conservation in Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Anthony D. Rollett; Hasso Weiland; Mohammed Alvi; Abhijit Brahme

    2005-08-31

    Carnegie Mellon University was teamed with the Alcoa Technical Center with support from the US Dept. of Energy (Office of Industrial Technology) and the Pennsylvania Technology Investment Authority (PTIA) to make processing of aluminum less costly and more energy efficient. Researchers in the Department of Materials Science and Engineering have investigated how annealing processes in the early stages of aluminum processing affect the structure and properties of the material. Annealing at high temperatures consumes significant amounts of time and energy. By making detailed measurements of the crystallography and morphology of internal structural changes they have generated new information that will provide a scientific basis for shortening processing times and consuming less energy during annealing.

  3. Molecular dynamics simulation of annealed ZnO surfaces

    International Nuclear Information System (INIS)

    The effect of thermally annealing a slab of wurtzite ZnO, terminated by two surfaces, (0001) (which is oxygen-terminated) and (0001¯) (which is Zn-terminated), is investigated via molecular dynamics simulation by using reactive force field (ReaxFF). We found that upon heating beyond a threshold temperature of ∼700 K, surface oxygen atoms begin to sublimate from the (0001) surface. The ratio of oxygen leaving the surface at a given temperature increases as the heating temperature increases. A range of phenomena occurring at the atomic level on the (0001) surface has also been explored, such as formation of oxygen dimers on the surface and evolution of partial charge distribution in the slab during the annealing process. It was found that the partial charge distribution as a function of the depth from the surface undergoes a qualitative change when the annealing temperature is above the threshold temperature

  4. Microstructural characterization of intercritically annealed low alloy PM steels

    Energy Technology Data Exchange (ETDEWEB)

    Gueral, A. [Materials Division, Technical Education Faculty, Metallurgy Education Department, Gazi University, 06500 Teknikokullar-Ankara (Turkey); Tekeli, S. [Materials Division, Technical Education Faculty, Metallurgy Education Department, Gazi University, 06500 Teknikokullar-Ankara (Turkey)]. E-mail: stekeli@gazi.edu.tr

    2007-07-01

    In this study, the applicability of intercritical annealing heat treatment, which is usually practiced to high strength low alloy ingot steels (HSLA), to low alloy powder metallurgy (PM) processed steels was investigated. With this heat treatment, it was intended to produce a dual-phase steel structure (ferrite + martensite) in PM steel. The effect of various amount of graphite addition on microstructure was also examined. For these purposes, atomized iron powder (Ancorsteel 1000) was mixed with 0.3 and 0.5 wt% graphite powder. The mixed powders were cold pressed at 700 MPa with single action and sintered at 1120 deg. C for 30 min under pure argon gas atmosphere. Some of the sintered specimens were directly annealed at intercritical heat treatment temperatures of 724, 735 and 760 deg. C and rapidly water quenched. Through these heat treatments, ferrite + martensite microstructure with coarse grain size were produced. The other sintered specimens were first austenitized at 890 deg. C for 12 min before intercritically annealing and then rapidly water quenched to produce fully martensitic structure. These specimens with fully martensitic microstructure were subsequently annealed at intercritical annealing temperatures of 724, 735 and 760 deg. C and rapidly water quenched. Ferrite + martensite microstructure with fine grain size was obtained by this route. The experimental results showed that martensite volume fraction increased with increasing intercritical annealing temperature as well as increasing graphite content. It is thought that mechanical properties of PM steels can be controlled by these heat treatments which are an alternative to traditional heat treatments of quenching + tempering applied usually to PM steels.

  5. Electron trap annealing in neutron transmutation doped silicon

    DEFF Research Database (Denmark)

    Guldberg, J.

    1977-01-01

    Silicon doped by neutron transmutation to 1.2×1014 phosphorus atoms/cm3 was investigated with deep level transient spectroscopy using evaporated Au/n-Si diodes. Seven bulk electron traps were identified which appear after 30 min N2 anneal at temperatures between 425 and 725 °C. Five of these...... annealed in the manner characteristic of intrinsic defects studied by EPR and ir spectroscopy. Two may be related to residual oxygen and carbon complexes. Applied Physics Letters is copyrighted by The American Institute of Physics....

  6. Monte Carlo simulation of primary recrystallization and annealing twinning

    International Nuclear Information System (INIS)

    The formation of annealing twins has been studied from the beginning of the 20th century and a variety of mechanisms have been suggested. Molecular dynamics simulations on the atomic scale have also been performed. This paper reports a microscale simulation of primary recrystallization and twinning of a nickel alloy based on the Monte Carlo approach. Different twin morphologies were simulated. A possible dependence of grain growth direction on twin formation during annealing was demonstrated. The formation of incoherent Σ3 and Σ9 boundaries is verified as the indirect outcome after coherent Σ3 formation

  7. The Simulated Annealing Algorithm Implemented by the MATLAB

    Directory of Open Access Journals (Sweden)

    Lin Lin

    2012-11-01

    Full Text Available This paper expounds the basic principle of simulated annealing algorithm which was applied to solve the function optimization problem and the algorithm realization process by using MATLAB language. Through the improvement algorithm results show that the method is able to function for global optimization, effectively overcome the based on the derivative of the optimization algorithm easy to fall into local optimum problems. This method not only can deepen the understanding of the simulated annealing process, but also can achieve the purpose of design intelligent system.

  8. Adiabatic quantum computation and quantum annealing theory and practice

    CERN Document Server

    McGeoch, Catherine C

    2014-01-01

    Adiabatic quantum computation (AQC) is an alternative to the better-known gate model of quantum computation. The two models are polynomially equivalent, but otherwise quite dissimilar: one property that distinguishes AQC from the gate model is its analog nature. Quantum annealing (QA) describes a type of heuristic search algorithm that can be implemented to run in the ``native instruction set'''' of an AQC platform. D-Wave Systems Inc. manufactures {quantum annealing processor chips} that exploit quantum properties to realize QA computations in hardware. The chips form the centerpiece of a nov

  9. Non-Hermitian Quantum Annealing in the Ferromagnetic Ising Model

    CERN Document Server

    Nesterov, Alexander I; Berman, Gennady P

    2013-01-01

    We developed a non-Hermitian quantum optimization algorithm to find the ground state of the ferromagnetic Ising model with up to 1024 spins (qubits). Our approach leads to significant reduction of the annealing time. Analytical and numerical results demonstrate that the total annealing time is proportional to ln N, where N is the number of spins. This encouraging result is important in using classical computers in combination with quantum algorithms for the fast solutions of NP-complete problems. Additional research is proposed for extending our dissipative algorithm to more complicated problems.

  10. Non-Hermitian Quantum Annealing in the Antiferromagnetic Ising Chain

    CERN Document Server

    Nesterov, Alexander I; Zepeda, Juan C Beas; Bishop, Alan R

    2013-01-01

    A non-Hermitian quantum optimization algorithm is created and used to find the ground state of an antiferromagnetic Ising chain. We demonstrate analytically and numerically (for up to N=1024 spins) that our approach leads to a significant reduction of the annealing time that is proportional to $\\ln N$, which is much less than the time (proportional to $N^2$) required for the quantum annealing based on the corresponding Hermitian algorithm. We propose to use this approach to achieve similar speed-up for NP-complete problems by using classical computers in combination with quantum algorithms.

  11. Higher oxidization rate of photo-assisted annealing compared with thermal annealing after YBa2Cu3O7−δ films growth

    International Nuclear Information System (INIS)

    Highlights: • The photo-assisted annealing has higher oxidization rate for the YBCO films was found. • The production efficiency of REBCO films were enhanced. • The experimental study for deoxidization has been executed. • Thermodynamics effect of photo-activation during annealing process has been analyzed. - Abstract: In order to study the possible advantage of photo-assisted MOCVD compared with thermal MOCVD during the annealing process after film growth, a piece of c-axis oriented YBa2Cu3O7−δ film on Φ1″ LaAlO3 (1 0 0) substrate was prepared by photo-assisted MOCVD. It has well in-plane alignment and high critical current density (Jc > 2.5 MA/cm2, @ 0 T, 77 K, thickness ≈ 430 nm). Small pieces cut from it were annealed by photo-assisted or thermal annealing process to realize deoxidization or oxidization respectively. By monitoring the c-axis lattice constant, it was found that oxidization rate of photo-assisted annealing is obviously higher than that of thermal annealing. Inversely, the deoxidization rate of photo-assisted annealing is lower than that of thermal annealing. And a phenomenon that the long-time stable c-axis lattice constant is related to the temperature, unrelated to annealing process has been observed. It conforms to the thermodynamic equilibrium which is relative to annealing temperature and oxygen partial pressure, irrespective to whether photo activation or thermal activation

  12. Air atmosphere annealing effects on LSO:Ce crystal

    Czech Academy of Sciences Publication Activity Database

    Ding, D.; Feng, H.; Ren, G.; Nikl, Martin; Qin, L.; Pan, S.; Yang, F.

    2010-01-01

    Roč. 57, č. 3 (2010), s. 1272-1277. ISSN 0018-9499 R&D Projects: GA MŠk ME08034 Institutional research plan: CEZ:AV0Z10100521 Keywords : annealing * cerium * LSO * luminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.519, year: 2010

  13. Effect of Annealing Conditions on Properties of BSCCO-2212 Bulk

    International Nuclear Information System (INIS)

    We fabricated BSCCO-2212(2212) bulk superconductors by using a casting process and evaluated the superconducting properties. The effects of annealing conditions on microstructure and critical properties were studied. It was found that the homogeneous and uniform microstructure improved the critical properties and the microstructures of ingot and annealed rods were different with the size of 2212 rod and tube. The critical current(Ic) of rods increased with increasing annealing time, probably due to increased grain size of 2212. Annealing time of the highest Icfor the smaller rod(diameter of 10 mm) was shorter(150 hr) than that of the larger rod(diameter of 16 mm, 400 hr). This size effect seems to be related to different grain sizes of the intermediate phases such as 2201 and secondary phases in the ingot. In addition, we fabricated 2212 tubes from the rod by removing the center region which contained inhomogeneous microstructures. The Icof 2212 tube with the outer diameter of 16 mm and the thickness of 2 mm was measured to 844 A, which corresponds to the critical current density of 1017 A/cm2 at 77 K.

  14. Thermal annealing and ionic abrasion in ZnTe

    International Nuclear Information System (INIS)

    Thermal annealing of the ZnTe crystal is studied first in order to obtain information on the aspect of the penetration profile. Ionic abrasion is then investigated to find out whether it produces the same effects as ionic implantation, especially for luminescence

  15. Annealing Twinning and the Nucleation of Recrystallization at Grain Boundaries

    DEFF Research Database (Denmark)

    Jones, A R.

    1981-01-01

    Experimental evidence is presented which shows that, in three different low stacking fault energy materials, annealing twins form at grain boundaries during the very early stages of recovery following deformation. These observations provide the basis for the suggestion that twinning at grain...

  16. Analysis of Trivium by a Simulated Annealing variant

    DEFF Research Database (Denmark)

    Borghoff, Julia; Knudsen, Lars Ramkilde; Matusiewicz, Krystian

    2010-01-01

    characteristic of equation systems that may be efficiently solvable by the means of such algorithms is provided. As an example, we investigate equation systems induced by the problem of recovering the internal state of the stream cipher Trivium. We propose an improved variant of the simulated annealing method...

  17. Function minimization with partially correct data via simulated annealing

    Science.gov (United States)

    Lorre, Jean J.

    1988-01-01

    The simulated annealing technique has been applied successfully to the problem of estimating the coefficients of a function in cases where only a portion of the data being fitted to the function is truly representative of the function, the rest being erroneous. Two examples are given, one in photometric function fitting and the other in pattern recognition. A schematic of the algorithm is provided.

  18. A Deterministic Annealing Approach to Clustering AIRS Data

    Science.gov (United States)

    Guillaume, Alexandre; Braverman, Amy; Ruzmaikin, Alexander

    2012-01-01

    We will examine the validity of means and standard deviations as a basis for climate data products. We will explore the conditions under which these two simple statistics are inadequate summaries of the underlying empirical probability distributions by contrasting them with a nonparametric, method called Deterministic Annealing technique

  19. Physical Mapping Using Simulated Annealing and Evolutionary Algorithms

    DEFF Research Database (Denmark)

    Vesterstrøm, Jacob Svaneborg

    2003-01-01

    Physical mapping (PM) is a method of bioinformatics that assists in DNA sequencing. The goal is to determine the order of a collection of fragments taken from a DNA strand, given knowledge of certain unique DNA markers contained in the fragments. Simulated annealing (SA) is the most widely used...

  20. A Simulated Annealing Methodology for Clusterwise Linear Regression.

    Science.gov (United States)

    DeSarbo, Wayne S.; And Others

    1989-01-01

    A method is presented that simultaneously estimates cluster membership and corresponding regression functions for a sample of observations or subjects. This methodology is presented with the simulated annealing-based algorithm. A set of Monte Carlo analyses is included to demonstrate the performance of the algorithm. (SLD)

  1. Application of Simulated Annealing to Clustering Tuples in Databases.

    Science.gov (United States)

    Bell, D. A.; And Others

    1990-01-01

    Investigates the value of applying principles derived from simulated annealing to clustering tuples in database design, and compares this technique with a graph-collapsing clustering method. It is concluded that, while the new method does give superior results, the expense involved in algorithm run time is prohibitive. (24 references) (CLB)

  2. Meta-Modeling by Symbolic Regression and Pareto Simulated Annealing

    NARCIS (Netherlands)

    Stinstra, E.; Rennen, G.; Teeuwen, G.J.A.

    2006-01-01

    The subject of this paper is a new approach to Symbolic Regression.Other publications on Symbolic Regression use Genetic Programming.This paper describes an alternative method based on Pareto Simulated Annealing.Our method is based on linear regression for the estimation of constants.Interval arithm

  3. Deep level defects in high temperature annealed InP

    Institute of Scientific and Technical Information of China (English)

    DONG; Zhiyuan; ZHAO; Youwen; ZENG; Yiping; DUAN; Manlong

    2004-01-01

    Deep level defects in high temperature annealed semi-conducting InP have been studied by deep level transient spectroscopy (DLTS). There is obvious difference in the deep defects between as-grown InP, InP annealed in phosphorus ambient and iron phosphide ambient, as far as their quantity and concentration are concerned. Only two defects at 0.24 and 0.64 eV can be detected in InP annealed iniron phosphide ambient,while defects at 0.24, 0.42, 0.54 and 0.64 eV have been detected in InP annealed in phosphorus ambient, in contrast to two defects at 0.49 and 0.64 eV or one defect at 0.13eV in as-grown InP. A defect suppression phenomenon related to iron diffusion process has been observed. The formation mechanism and the nature of the defects have been discussed.

  4. Internals removal and storage options for an actual annealing

    International Nuclear Information System (INIS)

    The objective of this paper was an overview of the options for storage of the reactor internals during an actual annealing process. Physical support of the internals, adequate shielding, and seals to protect the vessel from water leakage were considered in this review. Options considered were: (1) Canister approach, (2) Dam approach, and (3) Dry storage shielded cask approach

  5. Thermal annealing of protocrystalline a-Si:H

    NARCIS (Netherlands)

    Muller, T.F.G.; Arendse, C.J.; Halindintwali, S.; Knoesen, D.; Schropp, R.E.I.

    2011-01-01

    It proves difficult to obtain a set of protocrystalline silicon materials with different characteristics from the same deposition chamber to study the exact nature of these transition region materials. Hot-wire deposited protocrystalline silicon was thus isochronically annealed at different temperat

  6. EPR of ion-implanted, laser-annealed silicon

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance and ion backscattering measurements were made on ion-implanted, pulsed laser-annealed silicon. For phosphorus-implanted silicon (3 x 1013 200 keV P+/cm2) the electrical activity of the implanted donors is restored after laser annealing with greater than or equal to 1.8 J/cm2. Silicon made amorphous with 2 x 1015 200 keV Si+/cm2 and implanted with 3 x 1013 200 keV P+/cm2 can be restored to crystallinity after laser annealing, but electrical activity of the P was not restored due to residual defects for laser energies less than or equal to 3 J/cm2. Electrical activity can be restored, at least in part, for amorphous silicon implanted at lower energies (approx. = 50 keV). We also observed that N2 reacts with amorphous silicon surfaces to form silicon-nitride. Under laser annealing the N is redistributed and exists as an N interstitial within the implanted layer

  7. Off-diagonal magnetoimpedance in stress-annealed amorphous ribbons

    Czech Academy of Sciences Publication Activity Database

    Kraus, Luděk

    2008-01-01

    Roč. 320, č. 20 (2008), e746-e749. ISSN 0304-8853 Institutional research plan: CEZ:AV0Z10100520 Keywords : amorphous ribbon * giant magnetoimpedance * off-diagonal magnetoimpedance * stress annealing * magnetic anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.283, year: 2008

  8. Stabilization of metallic glass by isochronal and isothermal annealing treatments

    International Nuclear Information System (INIS)

    The internal friction (IF) of a Zr-Ti-Cu-Ni-Be metallic glass was measured using an inverted torsion pendulum with the free decay method. A single-roller melt-spinning apparatus was used for preparing the specimens. In the isochronal annealing experiment, specimens in different states were prepared by annealing, and the temperature dependence of the IF was measured from room temperature up to the crystallization temperature Tx. The glass attained a stabilized state under a long-time annealing near and below the glass transition temperature Tg. IF peaks always appeared near and below Tx, while an anomaly was observed clearly near Tg only in the stabilized state. A differential scanning calorimetry experiment was carried out for the same specimens, and the results showed the same characteristics. The isothermal annealing experiment revealed that the stabilization was a relaxation process, and how long a time was required for reaching the stabilized state. The essential features of glass-forming materials could be clearly observed when the specimens were in the stabilized state

  9. Stabilization of metallic glass by isochronal and isothermal annealing treatments

    Energy Technology Data Exchange (ETDEWEB)

    Hiki, Y [Tokyo Institute of Technology, 39-3-303 Motoyoyogi, Shibuya-ku, Tokyo 151-0062 (Japan); Tanahashi, M [Tokyo University of Science, Noda, Chiba 278-8510 (Japan); Tamura, R [Tokyo University of Science, Noda, Chiba 278-8510 (Japan); Takeuchi, S [Tokyo University of Science, Noda, Chiba 278-8510 (Japan); Takahashi, H [Ibaraki University, Nakanarusawa, Hitachi 316-0033 (Japan)

    2007-05-23

    The internal friction (IF) of a Zr-Ti-Cu-Ni-Be metallic glass was measured using an inverted torsion pendulum with the free decay method. A single-roller melt-spinning apparatus was used for preparing the specimens. In the isochronal annealing experiment, specimens in different states were prepared by annealing, and the temperature dependence of the IF was measured from room temperature up to the crystallization temperature T{sub x}. The glass attained a stabilized state under a long-time annealing near and below the glass transition temperature T{sub g}. IF peaks always appeared near and below T{sub x}, while an anomaly was observed clearly near T{sub g} only in the stabilized state. A differential scanning calorimetry experiment was carried out for the same specimens, and the results showed the same characteristics. The isothermal annealing experiment revealed that the stabilization was a relaxation process, and how long a time was required for reaching the stabilized state. The essential features of glass-forming materials could be clearly observed when the specimens were in the stabilized state.

  10. The afforestation problem: a heuristic method based on simulated annealing

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui

    1992-01-01

    This paper presents the afforestation problem, that is the location and design of new forest compartments to be planted in a given area. This optimization problem is solved by a two-step heuristic method based on simulated annealing. Tests and experiences with this method are also presented....

  11. Birefringence enhancement in annealed TiO2 thin films

    Science.gov (United States)

    van Popta, Andy C.; Cheng, June; Sit, Jeremy C.; Brett, Michael J.

    2007-07-01

    Postdeposition thermal annealing is used to enhance the form birefringence of nanostructured TiO2 thin films grown by electron-beam evaporation using the serial bideposition technique. Thin films were grown on fused silica substrates using oblique deposition angles between 60° and 75° and repetitive 180° substrate rotations to produce birefringent thin films that are structurally anisotropic. Postdeposition annealing in air, between 200 and 900°C, was used to increase the form birefringence of the films by changing the TiO2 phase from the as-deposited amorphous state to a polycrystalline state that exhibits a greater inherent density and larger bulk refractive index. The optical properties, microstructure, and crystallinity were characterized by Mueller matrix ellipsometry, scanning electron microscopy, atomic force microscopy, and x-ray diffraction. It was found that the in-plane birefringence increased significantly upon thermal annealing, in some cases yielding birefringence values that doubled in magnitude, from 0.11 to 0.22 at a wavelength of 550nm for films annealed at 400°C.

  12. Pulsed laser annealing of Be-implanted GaN

    International Nuclear Information System (INIS)

    Postimplantation thermal processing of Be in molecular-beam-epitaxy-grown GaN by rapid thermal annealing (RTA) and pulsed laser annealing (PLA) was investigated. It has been found that the activation of Be dopants and the repair of implantation-induced defects in GaN films cannot be achieved efficiently by conventional RTA alone. On the other hand, good dopant activation and surface morphology and quality were obtained when the Be-implanted GaN film was annealed by PLA with a 248 nm KrF excimer laser. However, observations of off-resonant micro-Raman and high-resolution x-ray-diffraction spectra indicated that crystal defects and strain resulting from Be implantation were still existent after PLA, which probably degraded the carrier mobility and limited the activation efficiency to some extent. This can be attributed to the shallow penetration depth of the 248 nm laser in GaN, which only repaired the crystal defects in a thin near-surface layer, while the deeper defects were not annealed out well. This situation was significantly improved when the Be-implanted GaN was subjected to a combined process of PLA followed by RTA, which produced good activation of the dopants, good surface morphology, and repaired bulk and surface defects well

  13. Self-Organization and Annealed Disorder in a Fracturing Process

    DEFF Research Database (Denmark)

    Caldarelli, Guido; Di Tolla, Francesco; Petri, Alberto

    1996-01-01

    We show that a vectorial model for inhomogeneous elastic media self-organizes under external stress. An onset of crack avalanches of every duration and length scale compatible with the lattice size is observed. The behavior is driven by the introduction of annealed disorder, i.e., by lowering the...

  14. Quantum Annealing at Google: Recent Learnings and Next Steps

    Science.gov (United States)

    Neven, Hartmut

    Recently we studied optimization problems with rugged energy landscapes that featured tall and narrow energy barriers separating energy minima. We found that for a crafted problem of this kind, called the weak-strong cluster glass, the D-Wave 2X processor achieves a significant advantage in runtime scaling relative to Simulated Annealing (SA). For instances with 945 variables this results in a time-to-99%-success-probability 109 times shorter than SA running on a single core. When comparing to the Quantum Monte Carlo (QMC) algorithm we only observe a pre-factor advantage but the pre-factor is large, about 106 for an implementation on a single core. We should note that we expect QMC to scale like physical quantum annealing only for problems for which the tunneling transitions can be described by a dominant purely imaginary instanton. We expect these findings to carry over to other problems with similar energy landscapes. A class of practical interest are k-th order binary optimization problems. We studied 4-spin problems using numerical methods and found again that simulated quantum annealing has better scaling than SA. This leaves us with a final step to achieve a wall clock speedup of practical relevance. We need to develop an annealing architecture that supports embedding of k-th order binary optimization in a manner that preserves the runtime advantage seen prior to embedding.

  15. Annealing texture of nanostructured steel-based composite

    International Nuclear Information System (INIS)

    In this study, the evolution of annealing texture in nanostructured steel-based composite processed by accumulative roll bonding (ARB) was investigated. Textural evolution after post-annealing of ARB-processed samples was evaluated using X-ray diffraction. There was a texture transition in the ε-fiber during ARB process and post-annealing treatment. Average grain size of the sample before and after the post-annealing was 73 nm and 1.8 µm, respectively, and the microstructures were relatively uniform. It was found that with increasing the number of cycles, the volume fraction of the low angle grain boundary (LAGB) decreased and that of the high angle grain boundary (HAGB) increased. Also, the shear texture was dominant after the second and third ARB cycles, while for other samples, the rolling texture was dominant. The two-cycle and three-cycle samples obviously indicated a weak α-fiber and γ-fiber and a relatively strong ζ-fiber. It was proposed that the recrystallization led to a decrease in the α-fiber and γ-fiber and rolling texture components such as {111}〈110〉 and {111}〈112〉. On the other hand, the grain growth after recrystallization resulted in an increase in the α-fiber and γ-fiber and rolling texture orientations

  16. Blue thermoluminescence emission of annealed lithium rich aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Correcher, V.; Rodriguez-Lazcano, Y., E-mail: v.correcher@ciemat.e [CIEMAT, Madrid (Spain); Garcia-Guinea, J.; Crespo-Feo, E. [Museo Nacional de Ciencias Naturales, Madrid (Spain)

    2010-09-15

    The blue thermoluminescence (TL) emission of different thermally annealed {beta}-eucryptite (LiAlSiO{sub 4}), virgilite-petalite (LiAlSi{sub 5}O{sub 12}) and virgilite-petalite-bikitaite (LiAlSi{sub 10}O{sub 22}) mixed crystals have been studied. The observed changes in the TL glow curves could be linked to simultaneous processes taking place in the lithium aluminosilicate lattice structure (phase transitions, consecutive breaking linking of bonds, alkali self-diffusion, redox reactions, etc). The stability of the TL signal after four months of storage performed at RT under red light, shows big differences between annealed (12 hours at 1200 deg C) and non-annealed samples. The fading process in non-annealed samples can be fitted to a first-order decay mathematical expression; however preheated samples could not be reasonably fitted due to the highly dispersion detected. The changes observed in the X-ray diffractograms are in the intensity of the peaks that denote modifications in the degree of crystallinity and, in addition, there are some differences in the appearance of new peaks that could suppose new phases (e.g. b-spodumene). (author)

  17. Ion implantation and annealing studies in III-V nitrides

    International Nuclear Information System (INIS)

    Ion implantation doping and isolation is expected to play an enabling role for the realization of advanced III-Nitride based devices. In fact, implantation has already been used to demonstrate n- and p-type doping of GaN with Si and Mg or Ca, respectively, as well as to fabricate the first GaN junction field effect transistor. Although these initial implantation studies demonstrated the feasibility of this technique for the III-Nitride materials, further work is needed to realize its full potential. After reviewing some of the initial studies in this field, the authors present new results for improved annealing sequences and defect studies in GaN. First, sputtered AlN is shown by electrical characterization of Schottky and Ohmic contacts to be an effect encapsulant of GaN during the 1,100 C implant activation anneal. The AlN suppresses N-loss from the GaN surface and the formation of a degenerate n+-surface region that would prohibit Schottky barrier formation after the implant activation anneal. Second, they examine the nature of the defect generation and annealing sequence following implantation using both Rutherford Backscattering (RBS) and Hall characterization. They show that for a Si-dose of 1 x 1016 cm-2 50% electrical donor activation is achieved despite a significant amount of residual implantation-induced damage in the material

  18. Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Guang-Wen; Qi, Zhen-Yu, E-mail: qizhy@sysucc.org.cn; Deng, Xiao-Wu [Department of Radiation Oncology, Sun Yat-Sen University Cancer Center and State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060 (China); Rosenfeld, Anatoly [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2014-05-15

    Purpose: To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters forin vivo intensity modulated radiation therapy (IMRT) dosimetry. Methods: Several MOSFETs were irradiated atd{sub max} using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. Results: More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. Conclusions: Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic.

  19. Surface Structure of Hydroxyapatite from Simulated Annealing Molecular Dynamics Simulations.

    Science.gov (United States)

    Wu, Hong; Xu, Dingguo; Yang, Mingli; Zhang, Xingdong

    2016-05-10

    The surface structure of hydroxyapatite (HAP) is crucial for its bioactivity. Using a molecular dynamics simulated annealing method, we studied the structure and its variation with annealing temperature of the HAP (100) surface. In contrast to the commonly used HAP surface model, which is sliced from HAP crystal and then relaxed at 0 K with first-principles or force-field calculations, a new surface structure with gradual changes from ordered inside to disordered on the surface was revealed. The disordering is dependent on the annealing temperature, Tmax. When Tmax increases up to the melting point, which was usually adopted in experiments, the disordering increases, as reflected by its radial distribution functions, structural factors, and atomic coordination numbers. The disordering of annealed structures does not show significant changes when Tmax is above the melting point. The thickness of disordered layers is about 10 Å. The surface energy of the annealed structures at high temperature is significantly less than that of the crystal structure relaxed at room temperature. A three-layer model of interior, middle, and surface was then proposed to describe the surface structure of HAP. The interior layer retains the atomic configurations in crystal. The middle layer has its atoms moved and its groups rotated about their original locations. In the surface layer, the atomic arrangements are totally different from those in crystal. In particular for the hydroxyl groups, they move outward and cover the Ca(2+) ions, leaving holes occupied by the phosphate groups. Our study suggested a new model with disordered surface structures for studying the interaction of HAP-based biomaterials with other molecules. PMID:27096760

  20. Surface precipitates formed on annealed LSAT (001) single crystal.

    Science.gov (United States)

    Ohashi, Kazuki; Okada, Shunsuke; Sasaki, Katsuhiro; Tokunaga, Tomoharu; Kobayashi, Shunsuke; Yamamoto, Takahisa

    2014-11-01

    LSAT (La0.3Sr0.7)(Al0.65Ta0.35)O3, which has a complex perovskite structure of (A'A'')(B'B'')O3, is expected as an attracting substrates for GaN and high temperature superconductivity oxides solid thin films from a viewpoint of the suitable lattice matching. To grow high quality thin film, it is very important to prepare step-terrace structure on substrates used for thin film growth. For this purpose, a technique of annealing substrates with mirror surface is often used. However, surface precipitates, called surface mounts, are reported to appear after annealing LSAT substrates [1]. In this study, we investigated the surface precipitates formed on annealed LSAT surfaces by TEM/STEM. Further, we directly confirmed the terminated atomic layers at the annealed LSAT surfaces in the area without surface precipitates.Commercially available LSAT single crystal substrates with (001) surfaces (SHINKOSHA CO.,LTD) were used for TEM/STEM observation. After annealing at 1300°C for 30 min in air, the (001) surface structures were observed from [110] direction using cross sectional thin foils. The thin foils were prepared by joining two annealed LSAT (001) surfaces with glue, grinding, polishing and finally Ar ion milling. TEM/STEM observation was conducted by JEOL ARM-200F (a double Cs-corrector type for TEM/STEM) operated at 200kV.Surface mounds were confirmed to appear on LSAT crystal surface after annealing at the annealing condition used in this study. A typical example is shown in Fig. 1. shows TEM bright field image taken from the surface area of LSAT (001) after annealing. The observation direction of the image is [110], which is parallel to the annealed surface. Cross sectional images of surface mounts with 300nm was clearly seen as indicated by the arrows in the image. The height of the mounts is around 20nm, and it is noted that the interfaces between the mounts and LSAT surfaces are hollowed into LSAT crystal with the depth about 10nm. Nano diffractometric and EDS

  1. Determination of the annealing for AISI430 steel in a continous furnace

    International Nuclear Information System (INIS)

    It's discussed a mathematical model, which represents the heating of a steel piece inside a continuous annealing furnace. It's described the experimental technique used to obtain good annealing conditions for a required quality. (Author)

  2. Transient spinodal decomposition during annealing of rapidly solidified Al-10Sr alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Rapidly solidified Al-10Sr alloy ribbons were prepared using a single roller melt spinning technique. The annealing process of the rapidly solidified Al-10Sr alloy has been carried out using differential scanning calorimetry (DSC). The microstructure of as-annealed Al-10Sr alloy has been characterized by transmission electron microscopy (TEM). The equilibrium Al4Sr phase is dominant in the as-annealed alloy. Besides the Al4Sr phase, an AlSr phase is also found in the alloy isothermally annealed at 873 K for 90 min. Furthermore, a modulated nanostructure was observed in the alloy isothermally annealed at 873 K for 90 min. With further prolonged annealing time, however, the AlSr phase disappears in the as-annealed alloy. The dependence of particle size and growth rate on annealing time as well as the modulated structure shows that the occurrence of the AlSr phase may be due to the spinodal decomposition.

  3. Application of simulated annealing algorithm to optimizing sequencing of operation steps

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Discusses the optimization of machining operation sequencing by simulated annealing, and building a simulated annealing optimization model. From which, a new way to optimize operation sequencing can be developed.

  4. Electron beam annealing of zinc implanted GaAs to control profile broadening

    International Nuclear Information System (INIS)

    Highly doped P+ layers have been obtained by using multiply scanned electron beam annealing. The diffusion of the zinc was controllable at temperatures above 900 deg C if anneal times were less than 3 s. (author)

  5. Performance enhancement of amorphous indium-zinc-oxide thin film transistors by microwave annealing

    Science.gov (United States)

    Xu, Rui; He, Jian; Li, Wei; Paine, David C.

    2015-12-01

    The effect of microwave annealing on the field effect mobility and threshold voltage of amorphous indium zinc oxide (a-IZO) thin film transistors (TFTs) is reported. A control device with traditional hotplate annealing at 200 °C for 1 h was applied for comparison. The results show that both microwave annealing and low-temperature hotplate annealing increase the field effect mobility from 12.3 cm2/V s in as-deposited state to ∼19 cm2/V s in annealed state. However, the negative shift in threshold voltage with microwave annealing (from 0.23 V to -2.86 V) is smaller than that with low-temperature hotplate annealing (to -9 V). A mechanism related with the electrical properties of a-IZO material is proposed. This rapid low-temperature annealing technology makes a-IZO TFTs promising for use in flexible, transparent electronics.

  6. MoO3 Thickness, Thermal Annealing and Solvent Annealing Effects on Inverted and Direct Polymer Photovoltaic Solar Cells

    Directory of Open Access Journals (Sweden)

    Guillaume Wantz

    2012-11-01

    Full Text Available Several parameters of the fabrication process of inverted polymer bulk heterojunction solar cells based on titanium oxide as an electron selective layer and molybdenum oxide as a hole selective layer were tested in order to achieve efficient organic photovoltaic solar cells. Thermal annealing treatment is a common process to achieve optimum morphology, but it proved to be damageable for the performance of this kind of inverted solar cells. We demonstrate using Auger analysis combined with argon etching that diffusion of species occurs from the MoO3/Ag top layers into the active layer upon thermal annealing. In order to achieve efficient devices, the morphology of the bulk heterojunction was then manipulated using the solvent annealing technique as an alternative to thermal annealing. The influence of the MoO3 thickness was studied on inverted, as well as direct, structure. It appeared that only 1 nm-thick MoO3 is enough to exhibit highly efficient devices (PCE = 3.8% and that increasing the thickness up to 15 nm does not change the device performance. 

  7. Polysilicon thin films fabricated by solid phase crystallization using reformed crystallization annealing technique

    International Nuclear Information System (INIS)

    In this work, a reformed crystallization annealing technique is presented for the solid phase crystallization (SPC) of amorphous silicon (a-Si) on SiNx-coated quartz substrate. This technique includes a two-step annealing process which consists of a low-temperature (475 °C) classical furnace annealing for nucleation of Si and a high-temperature (900 °C) grain growth process of polycrystalline silicon (poly-Si) during thermal annealing in classical tube furnace. The aim of this reformed two-step annealing technique is reducing the long (up to 48 h) crystallization annealing duration of single step annealing at low temperatures (∼ 600 °C) while maintaining the film quality, as low-temperature single step annealing, by using reformed technique. Continuous p-type poly-Si film was formed on quartz substrate thanks to exodiffusion of boron, which was deposited prior to a-Si, through Si film by thermal annealing. The stress and degree of crystallinity of the p-type poly-Si were studied by the micro-Raman Spectroscopy. The crystallization fraction value of 95% was deduced for annealed samples at 900 °C, independent from crystallization technique. On the other hand, the Raman analysis points out that compressive stress was induced by increasing the annealing duration at 900 °C. X-ray diffraction (XRD) analysis reveals that the preferred crystallite orientation of the films, independent from crystallization temperature and substrates, is <111>. Additionally, the average crystallite size calculated from XRD patterns increases from 69 Å to 165 Å by using reformed two-step annealing instead of single step annealing at 900 °C for 90 min. The exodiffusion of boron into the silicon film was deduced from secondary ion mass spectrometry (SIMS) analysis and the p+/p graded boron profile was obtained, which may result higher carrier diffusion length and longer carrier life time. Finally, the annealing duration dramatically decrease to 9 h by using reformed two-step annealing

  8. C-Curves of Tool Steels for Annealing and Their Application

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    TTT diagrams, CCT diagrams and critical points of steels H13, S7, S5 for annealing were measured and investigated by means of Formastor-Digital full-automatic phase transformation dilatometer in order to make their annealing technology reasonable and scientific. The basis is provided for making a new annealing technology scientifically. The new technology improves the quality of annealed materials, saves energy and increases productivity.

  9. Influence of Annealing Conditions on Structure and Optical Properties of Copper Nanoparticles Embedded in Silica Matrix

    OpenAIRE

    Yeshchenko, Oleg A.; Dmitruk, Igor. M.; Dmytruk, Andriy M.; Alexeenko, Alexandr A.

    2006-01-01

    Copper nanoparticles have been grown in silica matrix by annealing of the sol-gel prepared porous matrix impregnated with the copper nitrate. The annealing has been performed in air, successively in air and hydrogen, and in hydrogen. Cu nanoparticles in size range of 2-65 nm have been grown depending on annealing conditions. Annealing in air results in copper oxide nanoparticles (Cu2O) growth as well. Transmission electron microscopy (TEM) and optical spectroscopy of the copper nanoparticles ...

  10. Tunable metal-insulator transitions in bilayer graphene by thermal annealing

    OpenAIRE

    Kalon, Gopinadhan; Shin, Young Jun; Yang, Hyunsoo

    2012-01-01

    Tunable and highly reproducible metal-insulator transitions have been observed in bilayer graphene upon thermal annealing at 400 K under high vacuum conditions. Before annealing, the sample is metallic in the whole temperature regime of study. Upon annealing, the conductivity changes from metallic to that of an insulator and the transition temperature is a function of annealing time. The pristine metallic state can be reinstated by exposing to air thereby inducing changes in the electronic pr...

  11. Annealing twin development during recrystallization and grain growth in pure nickel

    OpenAIRE

    Jin, Yuan; Lin, Brian; Bernacki, Marc; Gregory S. Rohrer; Rollet, Anthony D.; Bozzolo, Nathalie

    2014-01-01

    International audience A 99.995% pure Ni sample, compressed to 25%, was annealed in a SEM chamber and changes in the density of annealing twins were monitored in situ during recrystallization and grain growth. In addition to average microstructural measurements, the evolution of individual grains was also observed. Both the average annealing twin density in the recrystallized domain and the annealing twin density per grain increased during recrystallization. The rate of increase in twin de...

  12. Microscopic Properties of Quantum Annealing -- Application to Fully Frustrated Ising Systems

    OpenAIRE

    Tanaka, Shu

    2011-01-01

    In this paper we show quantum fluctuation effect of fully frustrated Ising spin systems. Quantum annealing has been expected to be an efficient method to find ground state of optimization problems. However it is not clear when to use the quantum annealing. In order to clarify when the quantum annealing works well, we have to study microscopic properties of quantum annealing. In fully frustrated Ising spin systems, there are macroscopically degenerated ground states. When we apply quantum anne...

  13. Population Annealing with Weighted Averages: A Monte Carlo Method for Rough Free Energy Landscapes

    OpenAIRE

    Machta, Jon

    2010-01-01

    The population annealing algorithm introduced by Hukushima and Iba is described. Population annealing combines simulated annealing and Boltzmann weighted differential reproduction within a population of replicas to sample equilibrium states. Population annealing gives direct access to the free energy. It is shown that unbiased measurements of observables can be obtained by weighted averages over many runs with weight factors related to the free energy estimate from the run. Population anneali...

  14. Nonadiabatic Quantum Annealing for One-Dimensional Trasverse-Field Ising Model

    OpenAIRE

    Katsuda, Hitoshi; Nishimori, Hidetoshi

    2013-01-01

    We propose a nonadiabatic approach to quantum annealing, in which we repeat quantum annealing in nonadiabatic time scales, and collect the final states of many realizations to find the ground state among them. In this way, we replace the diffculty of long annealing time in adiabatic quantum annealing by another problem of the number of nonsidabatic (short-time) trials. The one-dimensional transverse-field Ising model is used to test this idea, and it is shown that nonadiabatic quantum anneali...

  15. Quantum Annealing Effect on Entropic Slowing Down in Frustrated Decorated Bond System

    OpenAIRE

    Tanaka, Shu; Miyashita, Seiji

    2006-01-01

    We propose that the importance of the quantum annealing procedure to find the ground state of frustrated decorated bond systems where 'entropic slowing down' happens due to peculiar density of states. Here, we use the time dependent Schr\\"odinger equation to analyze the real time dynamics of the process. It is found that the quantum annealing is very efficient comparing to the thermal annealing for searching the ground state of the systems. We analyze the mechanism of quantum annealing from a...

  16. Quantum Annealing: from Viewpoints of Statistical Physics, Condensed Matter Physics, and Computational Physics

    OpenAIRE

    Tanaka, Shu; Tamura, Ryo

    2012-01-01

    In this paper, we review some features of quantum annealing and related topics from viewpoints of statistical physics, condensed matter physics, and computational physics. We can obtain a better solution of optimization problems in many cases by using the quantum annealing. Actually the efficiency of the quantum annealing has been demonstrated for problems based on statistical physics. Then the quantum annealing has been expected to be an efficient and generic solver of optimization problems....

  17. Discrepancy between ambient annealing and H+ implantation in optical absorption of ZnO

    Science.gov (United States)

    Lv, Jinpeng; Li, Chundong

    2016-05-01

    The discrepancy between sub-bandgap absorption in ZnO induced by thermal annealing and H+ implantation is investigated in this study for the first time. Results indicate that nonreductive annealing-induced optical absorption is independent of annealing ambient, and can be assigned to VO, whereas the absorption centers caused by H+ implantation and H2 annealing are primarily associated with VO and ionized Zni.

  18. Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

    Institute of Scientific and Technical Information of China (English)

    Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

    2009-01-01

    Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

  19. Rapid thermal annealing and crystallization mechanisms study of silicon nanocrystal in silicon carbide matrix

    OpenAIRE

    Wan Zhenyu; Huang Shujuan; Green Martin; Conibeer Gavin

    2011-01-01

    Abstract In this paper, a positive effect of rapid thermal annealing (RTA) technique has been researched and compared with conventional furnace annealing for Si nanocrystalline in silicon carbide (SiC) matrix system. Amorphous Si-rich SiC layer has been deposited by co-sputtering in different Si concentrations (50 to approximately 80 v%). Si nanocrystals (Si-NC) containing different grain sizes have been fabricated within the SiC matrix under two different annealing conditions: furnace anneal...

  20. Superheated steam annealing of pressurized water reactor vessel

    International Nuclear Information System (INIS)

    Thermal annealing of an embrittled Reactor Pressure Shell is the only recognized means for recovering material properties lost due to long-term exposure of the reactor walls to radiation. Reduced toughness of the material during operation is a major concern in evaluations of structural integrity of older reactors. Extensive studies performed within programs related to life extension of nuclear plants have confirmed that the thermal treatment of 850 deg. F for 168 hours on irradiated material essentially recovers material properties lost due to neutron exposure. Dry and wet annealing methods have been considered. Wet annealing involves operating the reactor at near design temperatures and pressures. Since the temperature of wet annealing must be limited to vessel design temperature of 650 deg. F, only partial recovery of the lost properties is achieved. Thus dry annealing was selected as an alternative for future development and industrial implementation to extend the safe life of reactors. Dry thermal annealing consists of heating portions of the reactor vessel at a specific temperature for a given period of time using a high temperature heat source. The use of spent fuel assemblies, induction heating and resistance heating elements as well as the circulation of heated fluid were investigated as potential candidate methods. To date the use of resistance heating elements which are lowered into a dry empty reactor was considered to be the preferred method. In-depth research in the United States and practical applications of such a method in Russia have confirmed feasibility of the method. The method of using circulating superheated steam to anneal the vessel at 850 deg. F without complete removal of the reactor internals is described herein. After removing the reactor head and fuel, the core barrel along with the upper and lower core in PWRs is lifted to open an annular space between the reactor shell flange and the core barrel flange. The thermal shield can remain

  1. ANNEALING EFFECT ON MAGNETO-ELASTIC WAVE PROPAGATION IN IRON-RICH AMORPHOUS RIBBON

    OpenAIRE

    Yamada, K; Matsumoto, K.; Hasegawa, A.; Hiratsuka, N.

    1988-01-01

    The appropriate annealing of the iron-rich amorphous ribbon caused an enhancement of the magneto-elastic wave (MEW) amplitude. But the fluctuation of MEW with the distance along the ribbon became larger by any annealing. The differential magnetization curve sensitively showed a structural relaxation by the annealing.

  2. Quantitative microstructure characterization of self-annealed copper films with electron backscatter diffraction

    DEFF Research Database (Denmark)

    Pantleon, Karen; Gholinia, A.; Somers, Marcel A. J.

    2008-01-01

    Electron backscatter diffraction (EBSD) was applied to analyze cross sections of self-annealed copper electrodeposits, for which earlier the kinetics of self-annealing had been investigated by in-situ X-ray diffraction (XRD). The EBSD investigations on the grain size, grain boundary character and...... microstructure evolution at room temperature (self-annealing)....

  3. 10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Requirements for thermal annealing of the reactor pressure... Requirements for thermal annealing of the reactor pressure vessel. (a) For those light water nuclear power... thermal annealing may be applied to the reactor vessel to recover the fracture toughness of the...

  4. Electron spin resonance in neutron-irradiated graphite. Dependence on temperature and effect of annealing

    International Nuclear Information System (INIS)

    The temperature dependence of the electron spin resonance signal from neutron irradiated graphite has been studied. The results lead to an interpretation of the nature of the paramagnetic centers created by irradiation. In annealing experiments on graphite samples, which had been irradiated at low temperature, two annealing peaks and one anti-annealing peak were found. Interpretations are proposed for these peaks. (author)

  5. Influence of Microwave and Conventional Annealing Processes in Improving an Electrodeposited Nickel Interlayer Characteristics

    Science.gov (United States)

    Hassan, Abdelkarim; Noordin, Mohd Yusof; Izman, Sudin; Denni, Kurniawan

    2016-07-01

    Nickel interlayer was coated on tungsten carbide substrate by electrodeposition process for the purpose of diamond deposition. Conventional and microwave annealing processes were used to improve the adhesion strength and modify the surface composition of the electroplated nickel interlayer. The conventional annealing was conducted in a high-temperature tube furnace at 1323.15 K (1050 °C) for 20 and 60 minutes annealing durations. The microwave annealing was carried out in 2.45 GHz microwave furnace at 1303.15 K (1030 °C) for the same annealing durations as the conventional process. The annealed specimens were characterized by electron microscopy, Energy dispersive X-ray spectroscopy, and X-ray diffraction technique. Adhesion of the annealed nickel interlayer was assessed by the scratch test. The results revealed significant changes in the nickel coating composition, adhesion, and appearance. The adhesion strength of nickel interlayer annealed for the longer duration of the two processes is similar. For shorter annealing duration, the microwave-annealed coating showed better adhesion. The surface composition of the nickel interlayer was modified by the diffusion of carbon and tungsten during the microwave and conventional annealing, respectively. The microwave annealing is a promising process for producing good quality treated nickel-coated tungsten carbide specimens.

  6. First application of quantum annealing to IMRT beamlet intensity optimization

    International Nuclear Information System (INIS)

    Optimization methods are critical to radiation therapy. A new technology, quantum annealing (QA), employs novel hardware and software techniques to address various discrete optimization problems in many fields. We report on the first application of quantum annealing to the process of beamlet intensity optimization for IMRT.We apply recently-developed hardware which natively exploits quantum mechanical effects for improved optimization. The new algorithm, called QA, is most similar to simulated annealing, but relies on natural processes to directly minimize a system’s free energy. A simple quantum system is slowly evolved into a classical system representing the objective function. If the evolution is sufficiently slow, there are probabilistic guarantees that a global minimum will be located.To apply QA to IMRT-type optimization, two prostate cases were considered. A reduced number of beamlets were employed, due to the current QA hardware limitations. The beamlet dose matrices were computed using CERR and an objective function was defined based on typical clinical constraints, including dose-volume objectives, which result in a complex non-convex search space. The objective function was discretized and the QA method was compared to two standard optimization methods, simulated annealing and Tabu search, run on a conventional computing cluster.Based on several runs, the average final objective function value achieved by the QA was 16.9 for the first patient, compared with 10.0 for Tabu and 6.7 for the simulated annealing (SA) method. For the second patient, the values were 70.7 for the QA, 120.0 for Tabu and 22.9 for the SA. The QA algorithm required 27–38% of the time required by the other two methods.In this first application of hardware-enabled QA to IMRT optimization, its performance is comparable to Tabu search, but less effective than the SA in terms of final objective function values. However, its speed was 3–4 times faster than the other two methods

  7. Influence of phosphate esters on the annealing properties of starch

    DEFF Research Database (Denmark)

    Wischmann, Bente; Muhrbeck, Per

    1998-01-01

    The effects of annealing on native potato, waxy maize, and phosphorylated waxy maize starches were compared. Phosphorylated waxy maize starch responded to annealing in a manner between that of the naturally phosphorylated potato starch and that of the native waxy maize starch. The gelatinisation...... end-point temperature was increased, whereas in the native waxy maize it was decreased. On the other hand, the onset temperature change was much larger in potato starch than in the two waxy maize starches. Steeping also yielded intermediate effects on the phosphorylated waxy maize starch. It was...... concluded that the phosphate groups have similar effects as they do in the native, naturally phosphorylated potato starch, although the substitution pattern is not entirely the same in the artificially phosphorylated starch....

  8. Radiation annealing of gallium arsenide implanted with sulphur

    CERN Document Server

    Ardyshev, V M

    2002-01-01

    Sulfur ions were implanted in a semi-insulating GaAs. Photon annealing (805 deg C/(10-12) s) and the thermal one (800 deg C/30 min) were conducted under SiO sub 2 -films coating obtained by different ways. Contents of GaAs components in films were determined from Rutherford backscattering spectra; concentration profiles of electrons were measured by the voltage-capacitance method. Diffusion of sulfur was shown to go in two directions - to the surface and into bulk of GaAs. The first process was induced by vacancies that had been formed near the surface of semiconductors during the dielectric coating. The coefficient of the bulk-diffusion and diffusion-to-surface of sulfur ions under photon annealing was twice as much as that under thermal one. The doping efficiency was also larger

  9. Parallel simulated annealing algorithms for cell placement on hypercube multiprocessors

    Science.gov (United States)

    Banerjee, Prithviraj; Jones, Mark Howard; Sargent, Jeff S.

    1990-01-01

    Two parallel algorithms for standard cell placement using simulated annealing are developed to run on distributed-memory message-passing hypercube multiprocessors. The cells can be mapped in a two-dimensional area of a chip onto processors in an n-dimensional hypercube in two ways, such that both small and large cell exchange and displacement moves can be applied. The computation of the cost function in parallel among all the processors in the hypercube is described, along with a distributed data structure that needs to be stored in the hypercube to support the parallel cost evaluation. A novel tree broadcasting strategy is used extensively for updating cell locations in the parallel environment. A dynamic parallel annealing schedule estimates the errors due to interacting parallel moves and adapts the rate of synchronization automatically. Two novel approaches in controlling error in parallel algorithms are described: heuristic cell coloring and adaptive sequence control.

  10. Annealing free, clean graphene transfer using alternative polymer scaffolds

    International Nuclear Information System (INIS)

    We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications. (paper)

  11. Post annealing investigations of thin praseodymia films on Si(111)

    International Nuclear Information System (INIS)

    Due to its large oxygen capacity and oxygen mobility praseodymia is interesting for applications in modern heterogenous catalysis. For instance the selectivity of praseodymia for carbon compounds is advantageous in olefiant gas synthesis. The investigation of annealing processes leads to a better understanding of the oxygen transport in the praseodymia films. In this context thin PrO2 films were annealed at temperatures from 300 C up to 600 C under UHV conditions before they were analysed with spot analysis profile low electron energy diffraction (SPALEED). The diffraction pattern indicates a phase transition to Pr2O3 at the surface. Furthermore X-ray diffraction experiments (XRD) show a partial subsurface phase transition from PrO2 into various oxidation states including Pr2O3

  12. Substructure stability of tungsten single crystals at high temperature annealing

    International Nuclear Information System (INIS)

    The effect is studied of isothermal annealing at (2600-2800) deg C for several hours on the growth substructure of tungsten single crystals of variable freedom from interstitials (varying within two orders of magnitude) and of W single crystals with additions of 0.1 and 4 at % Re, obtained by electron-beam crucible-free zone recrystallization. It is shown that the streaky structure of W and W+0.1 at.% Re single crystals, formed in the high-temperature effect zone during their post-solidification cooling, is relatively stable. A higher stability is shown by the specimens with an interstitials concentration roughly identical to 0.1 at.% and/or the same concenctration of the alloying addition. The cellular-fibrous substructure in W+4 at.%Re specimens formed at the crystal/melt interface is unstable. The high-temperature annealing brings about its transformation into a more equiaxial substructure

  13. Low-temperature electron irradiation and annealing in pure magnesium

    International Nuclear Information System (INIS)

    In this study of magnesium after 1.0 MeV electron irradiations at 1.550K, it has been observed that the damage production rate in Mg is (3.57 +- 0.03) x 10-26 Ωcm/(e- cm2). There is no evidence for thermal annealing up to 40K. The low temperature recovery in magnesium is found to consist of two broad substages between 4 to 140K, both of which exhibit evidence for correlated and uncorrelated recovery processes. The two substages are found to have very different frequency factors for annealing, and there is evidence that the recovery processes in the second substage are influenced by those in the first. A model for recovery is proposed using the split configuration in the plane which explains the first substage as being due to interstitial migration in the basal plane and the second to migration perpendicular to the plane

  14. In situ austenite–martensite interface mobility study during annealing

    International Nuclear Information System (INIS)

    A 1C3Mn1.5Si steel was partially transformed into martensite by quenching to room temperature after full austenitisation. A partitioning treatment was applied in situ in a high resolution transmission electron microscope. The width of an austenite grain in between martensite constituents was followed as a function of the annealing time. Migration of the martensite–austenite interfaces was quantitatively measured and compared with results from a model for carbon partitioning from martensite to austenite involving interface motion. The kinetics of the observed movement suggests that the interface has a semi-coherent nature. This work shows that grain boundary mobility of the martensite–austenite interfaces during annealing may play an important role in the microstructure development during the process of Quenching and Partitioning in steels

  15. Temperature-dependent permittivity of annealed and unannealed gold films

    CERN Document Server

    Shen, Po-Ting; Lin, Cheng-Wei; Liu, Hsiang-Lin; Chang, Chih-Wei; Chu, Shi-Wei

    2016-01-01

    Due to local field enhancement and subwavelength confinements, nano-plasmonics provide numerous novel applications. Simultaneously, as an efficient nanoscale heat generator from inherent absorption, thermo-plasmonics is emerging as an important branch. However, although significant temperature increase is involved in applications, detailed characterization of metal permittivity at different temperatures is lacking. In this work, we extract the permittivity of gold film from 300K to the annealing temperature of 570K. By comparing annealed and unannealed films, more than one-order difference in thermo-derivative of permittivity is revealed, resulting in unexpectedly large variation of plasmonic properties. Our result is valuable not only for characterizing extensively used unannealed nanoparticles, but also for designing future thermo-nano-plasmonic systems.

  16. Optimization of pipe networks including pumps by simulated annealing

    OpenAIRE

    Costa A.L.H.; Medeiros J.L.; Pessoa F.L.P.

    2000-01-01

    The objective of this work is to present an application of the simulated annealing method for the optimal design of pipe networks including pumps. Although its importance, the optimization of pumped networks did not receive great attention in the literature. The proposed search scheme explores the discrete space of the decision variables: pipe diameters and pump sizes. The behavior of the pumps is describe through the characteristic curve, generating more realistic solutions. In order to demo...

  17. Convergence of simulated annealing by the generalized transition probability

    OpenAIRE

    Nishimori, Hidetoshi; Inoue, Jun-Ichi

    1998-01-01

    We prove weak ergodicity of the inhomogeneous Markov process generated by the generalized transition probability of Tsallis and Stariolo under power-law decay of the temperature. We thus have a mathematical foundation to conjecture convergence of simulated annealing processes with the generalized transition probability to the minimum of the cost function. An explicitly solvable example in one dimension is analyzed in which the generalized transition probability leads to a fast convergence of ...

  18. Barium ferrite powders prepared by milling and annealing

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-05-01

    Full Text Available Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment.Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950 °C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force (HC for mixture of powders annealed at 950 °C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. The arithmetic mean of diameter of Fe2O3 and BaCO3 mixture powders after 30 hours of milling is about 6.0 μm.Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable components to produce sintered and elastic magnets with polymer matrix.Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials.

  19. Optimization of multiple-layer microperforated panels by simulated annealing

    DEFF Research Database (Denmark)

    Ruiz Villamil, Heidi; Cobo, Pedro; Jacobsen, Finn

    2011-01-01

    Sound absorption by microperforated panels (MPP) has received increasing attention the past years as an alternative to conventional porous absorbers in applications with special cleanliness and health requirements. The absorption curve of an MPP depends on four parameters: the holes diameter, the....... Therefore, simulated annealing is proposed in this paper as a tool to solve the optimization problem of finding the best combination of the constitutive parameters of an ML-MPP providing the maximum average absorption within a prescribed frequency band....

  20. Reverse degradation of nickel graphene junction by hydrogen annealing

    CERN Document Server

    Zhang, Zhenjun; Agnihotri, Pratik; Lee, Ji Ung; Lloyd, Jim R

    2016-01-01

    Metal contacts are fundamental building components for graphene based electronic devices and their properties are greatly influenced by interface quality during device fabrication, leading to resistance variation. Here we show that nickel graphene junction degrades after air exposure, due to interfacial oxidation, thus creating a tunneling barrier. Most importantly, we demonstrate that hydrogen annealing at moderate temperature (300 0C) is an effective technique to reverse the degradation.

  1. Metallic glass composition. [That does not embrittle upon annealing

    Science.gov (United States)

    Kroeger, D.M.; Koch, C.C.

    1984-09-14

    This patent pertains to a metallic glass alloy that is either iron-based or nickel-based or based on a mixture of iron and nickel, containing lesser amounts of elements selected from the group boron, silicon, carbon and phosphorous to which is added an amount of a ductility-enhancing element selected from the group cerium, lanthanum, praseodymium and neodymium sufficient to increase ductility of the metallic glass upon annealing.

  2. Solving geometric constraints with genetic simulated annealing algorithm

    Institute of Scientific and Technical Information of China (English)

    刘生礼; 唐敏; 董金祥

    2003-01-01

    This paper applies genetic simulated annealing algorithm (SAGA) to solving geometric constraint problems. This method makes full use of the advantages of SAGA and can handle under-/over- constraint problems naturally. It has advantages (due to its not being sensitive to the initial values) over the Newton-Raphson method, and its yielding of multiple solutions, is an advantage over other optimal methods for multi-solution constraint system. Our experiments have proved the robustness and efficiency of this method.

  3. Simulated Annealing for the 0/1 Multidimensional Knapsack Problem

    Institute of Scientific and Technical Information of China (English)

    Fubin Qian; Rui Ding

    2007-01-01

    In this paper a simulated annealing (SA) algorithm is presented for the 0/1 multidimensional knapsack problem. Problem-specific knowledge is incorporated in the algorithm description and evaluation of parameters in order to look into the performance of finite-time implementations of SA. Computational results show that SA performs much better than a genetic algorithm in terms of solution time, whilst having a modest loss of solution quality.

  4. Adaptive Simulated Annealing Based Protein Loop Modeling of Neurotoxins

    Institute of Scientific and Technical Information of China (English)

    陈杰; 黄丽娜; 彭志红

    2003-01-01

    A loop modeling method, adaptive simulated annealing, for ab initio prediction of protein loop structures, as an optimization problem of searching the global minimum of a given energy function, is proposed. An interface-friendly toolbox-LoopModeller in Windows and Linux systems, VC++ and OpenGL environments is developed for analysis and visualization. Simulation results of three short-chain neurotoxins modeled by LoopModeller show that the method proposed is fast and efficient.

  5. Copolymer template control of gold nanoparticle synthesis via thermal annealing

    OpenAIRE

    Plaud, A.; Sarrazin, A.; Béal, J.; Proust, J.; Royer, P.; Bijeon, J. -L.; Plain, J.; Adam, P. -M.; Maurer, T

    2013-01-01

    We present here an original process combining top-down and bottom-up approaches by annealing a thin gold film evaporated onto a hole template made by etching a PS-PMMA copolymer film. Such process allows a better control of the gold nanoparticle size distribution which provides a sharper localized surface plasmon resonance. This makes such route appealing for sensing applications since the figure of merit of the Au nanoparticles obtained after thermal evaporation is more than doubled. Such pr...

  6. Photoluminescence of polycrystalline ZnO under different annealing conditions

    Science.gov (United States)

    Hur, Tae-Bong; Jeen, Gwang Soo; Hwang, Yoon-Hwae; Kim, Hyung-Kook

    2003-11-01

    We investigated polycrystalline zinc oxide (ZnO) with different annealing conditions in air by x-ray photoelectron spectroscopy and photoluminescence. We found that the concentration of antisite oxide (OZn) increases when ZnO ceramics were in an O-rich condition. As the concentration of antisite oxide (OZn) increased, the photoluminescence intensity of the green band emission increased. The crossover temperature of the free and bound excitons was roughly estimated as 100 K.

  7. The Simulated Annealing Algorithm Implemented by the MATLAB

    OpenAIRE

    Lin Lin; Chen Fei

    2012-01-01

    This paper expounds the basic principle of simulated annealing algorithm which was applied to solve the function optimization problem and the algorithm realization process by using MATLAB language. Through the improvement algorithm results show that the method is able to function for global optimization, effectively overcome the based on the derivative of the optimization algorithm easy to fall into local optimum problems. This method not only can deepen the understanding of the simulated ann...

  8. The role of particles annealing temperature on magnetorheological effect

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, M.; Pavlínek, V.; Sáha, P.; Švrčinová, Petra; Filip, Petr

    Singapore: World Scientific, 2011 - (Tao, R.), s. 363-368 ISBN 978-981-4340-22-9. [International Conference on Electro-Rheological Fluids and Magneto -Rheological Suspensions /12./. Philadelphia (US), 16.08.2010-20.08.2010] Grant ostatní: GA ČR(CZ) GA202/09/1626 Institutional research plan: CEZ:AV0Z20600510 Keywords : cobalt ferrite * annealing process * magneto metry * magnetization Subject RIV: BK - Fluid Dynamics

  9. Reverse degradation of nickel graphene junction by hydrogen annealing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhenjun; Yang, Fan; Agnihotri, Pratik; Lee, Ji Ung; Lloyd, J. R., E-mail: jlloyd@sunypoly.edu [College of Nanoscience and Engineering, SUNY Polytechnic Institute, Albany, NY USA 12203 (United States)

    2016-02-15

    Metal contacts are fundamental building components for graphene based electronic devices and their properties are greatly influenced by interface quality during device fabrication, leading to resistance variation. Here we show that nickel graphene junction degrades after air exposure, due to interfacial oxidation, thus creating a tunneling barrier. Most importantly, we demonstrate that hydrogen annealing at moderate temperature (300 {sup 0}C) is an effective technique to reverse the degradation.

  10. On-Orbit Annealing of Satellite Solar Panels

    OpenAIRE

    Michael, Sherif; Sommers, R.S.

    1988-01-01

    An approach to extend the life of orbiting satellites is presented. Since output power of spacecraft solar panels plays a major role in determining the end of life of the satellite, any attempt to recover any of this lost power would be very attractive. The goal of this research was to investigate the possibility of annealing radiation damaged solar panels under conditions that would be feasible to apply in orbiting spacecraft. Preliminary data of a technique called forward biased current ann...

  11. Reversible Jump MCMC Simulated Annealing for Neural Networks

    OpenAIRE

    Andrieu, Christophe; De Freitas, Nando; Doucet, Arnaud

    2013-01-01

    We propose a novel reversible jump Markov chain Monte Carlo (MCMC) simulated annealing algorithm to optimize radial basis function (RBF) networks. This algorithm enables us to maximize the joint posterior distribution of the network parameters and the number of basis functions. It performs a global search in the joint space of the parameters and number of parameters, thereby surmounting the problem of local minima. We also show that by calibrating a Bayesian model, we can obtain the classical...

  12. Near field modal noise reduction using annealed optical fiber

    OpenAIRE

    Osterman, Steve N.; Ycas, Gabriel G.; Donaldson, Chelsea L.; Diddams, Scott A.; Mahadevan, Suvrath; Ramsey, Lawrence W.; Plavchan, Peter P.

    2014-01-01

    Incomplete and unstable mode population has long complicated the application of optical fiber for transferring star and calibration light to high precision spectrographs. The need for improved precision calibrators in support of radial velocity planet surveys has led to the introduction of coherent wavelengths sources using single mode fibers that are then coupled into multi-mode fibers, further exacerbating this problem. We explore mode scrambling in annealed optical fiber with and without a...

  13. Annealing in sulfur of CZTS nanoparticles deposited through doctor blading

    OpenAIRE

    Engberg, Sara Lena Josefin; Crovetto, Andrea

    2014-01-01

    Solar cells made from nanoparticles of copper zinc tin sulfide (CZTS) from solution-processing are expected to be comparatively inexpensive, but their efficiency is still low compared with cells produced by vacuum processing. However, (1) the high carbon content in nanoparticle thin films is one of the main limitations for this approach, and (2) grain boundaries and defects are believed to be a site for recombination that limit the efficiency. Annealing in vacuum and/or nitrogen atmosphere fa...

  14. Rapid annealing using the water-wall arc lamp

    Science.gov (United States)

    Gelpey, Jeffrey C.; Stump, Paul O.

    1985-01-01

    Rapid annealing techniques using graphite strip heaters [1], tungsten-halogen lamps [2], and conventional arc lamps [3] have been gaining favor to provide controllable activation of ion implants while minimizing the diffusion of the implanted dopant. These conventional heat sources have given good results, but they all suffer from limitations in power output and/or the ability to change power levels rapidly. The water-wall d.c. arc lamp overcomes these limitations and allows precise control and excellent reproducability of the anneal cycle. The high power output and excellent optical coupling of the water-wall lamp allows ilumination from one side of the sample. The wafer temperature can then be directly monitored with a pyrometer and the fast response time of the lamp allows the pyrometer output to control the lamp power and, hence, provide direct feedback control of the wafer temperature. Direct control is important to overcome variations caused by different doping levels or dielectric coatings on the wafers. Annealing experiments using the water-wall lamp have shown that good activation and essentially complete removal of implant damage can be achieved while moving the junction only minimally [4,5]. The degree of dopant diffusion (generally on the order of 1000 Å) is small compared to device dimensions but is somewhat more than would be expected from classical diffusion theory using published diffusion coefficients. The differences depend on the implanted species and models are being developed to explain the discrepancies. The vary rapid heating and cooling rates obtainable with the water-wall lamp offer a great deal of flexibility in the time/temperature cycles used for annealing (or other rapid thermal processes). There are indications that the ability to achieve a rapid cooling rate allows more complete activation of high dose implants and rapid heating rates may reduce the residual damage and amount of diffusion.

  15. Rapid annealing using the water-wall arc lamp

    Energy Technology Data Exchange (ETDEWEB)

    Gelpey, J.C.; Stump, P.O. (Eaton Corp., Beverly, MA (USA). Semiconductor Equipment Operations)

    1985-01-01

    Rapid annealing techniques using graphite strip heaters, tungsten-halogen lamps and conventional arc lamps have been gaining favor to provide controllable activation of ion implants while minimizing the diffusion of the implanted dopant. These conventional heat sources have given good results, but they all suffer from limitations in power output and/or the ability to change power levels rapidly. The water-wall d.c. arc lamp overcomes these limitations and allows precise control and excellent reproducability of the anneal cycle. The high power output and excellent optical coupling of the water-wall lamp allows ilumination from one side of the sample. The wafer temperature can then be directly monitored with a pyrometer and the fast response time of the lamp allows the pyrometer output to control the lamp power and, hence, provide direct feedback control of the wafer temperature. Direct control is important to overcome variations caused by different doping levels or dielectric coatings on the wafers. Annealing experiments using the water-wall lamp have shown that good activation and essentially complete removal of implant damage can be achieved while moving the junction only minimally. The degree of dopant diffusion (generally on the order of 1000 A) is small compared to device dimensions but is somewhat more than would be expected from classical diffusion theory using published diffusion coefficients. The differences depend on the implanted species and models are being developed to explain the discrepancies. The vary rapid heating and cooling rates obtainable with the water-wall lamp offer a great deal of flexibility in the time/temperature cycles used for annealing (or other rapid thermal processes). There are indications that the ability to achieve a rapid cooling rate allows more complete activation of high dose implants and rapid heating rates may reduce the residual damage and amount of diffusion.

  16. Rapid annealing using the water-wall arc lamp

    International Nuclear Information System (INIS)

    Rapid annealing techniques using graphite strip heaters, tungsten-halogen lamps and conventional arc lamps have been gaining favor to provide controllable activation of ion implants while minimizing the diffusion of the implanted dopant. These conventional heat sources have given good results, but they all suffer from limitations in power output and/or the ability to change power levels rapidly. The water-wall d.c. arc lamp overcomes these limitations and allows precise control and excellent reproducability of the anneal cycle. The high power output and excellent optical coupling of the water-wall lamp allows ilumination from one side of the sample. The wafer temperature can then be directly monitored with a pyrometer and the fast response time of the lamp allows the pyrometer output to control the lamp power and, hence, provide direct feedback control of the wafer temperature. Direct control is important to overcome variations caused by different doping levels or dielectric coatings on the wafers. Annealing experiments using the water-wall lamp have shown that good activation and essentially complete removal of implant damage can be achieved while moving the junction only minimally. The degree of dopant diffusion (generally on the order of 1000 A) is small compared to device dimensions but is somewhat more than would be expected from classical diffusion theory using published diffusion coefficients. The differences depend on the implanted species and models are being developed to explain the discrepancies. The vary rapid heating and cooling rates obtainable with the water-wall lamp offer a great deal of flexibility in the time/temperature cycles used for annealing (or other rapid thermal processes). There are indications that the ability to achieve a rapid cooling rate allows more complete activation of high dose implants and rapid heating rates may reduce the residual damage and amount of diffusion. (orig.)

  17. Optical spectroscopy of undoped PbWO4 powders with different annealing atmospheres

    International Nuclear Information System (INIS)

    The photoacoustic spectrum, which is performed for the first time, optical reflection, and excitation and emission spectra of undoped PbWO4 powders with different annealing atmospheres were compared and analyzed. The red shifts of the absorption edge and the increased absorption around 425 and 600-800 nm in the vacuum annealed sample with respect to that in the oxygen annealed sample indicate the decrease of the O- centers in the sample. The increase of the blue luminescence in a vacuum annealing atmosphere suggests that annealing under vacuum atmosphere produces PbWO4 crystals with a better light yield

  18. Effects of Primary Annealing Condition on Recrystallization Texture in a Grain Oriented Silicon Steel

    Institute of Scientific and Technical Information of China (English)

    Yuhui SHA; Fang ZHANG; Song LI; Xiaoyu GAO; Jiazhen XU; Liang ZUO

    2004-01-01

    The recrystallization texture in grain oriented silicon steel sheets, which were annealed at different primary annealing temperatures with and without an electric field, was investigated. An automated electron backscattered diffraction (EBSD) technique was used to analyze the recrystallization texture. It was found that recovery and application of electric field in primary annealing lead to an increase of {001} component and a decrease of {111} component after annealing at 900℃. The development of recrystallization texture can be explained in terms of the effects of electric field and primary annealing temperature on recovery.

  19. Effect of thermal-annealing on the magnetoresistance of manganite-based junctions

    Institute of Scientific and Technical Information of China (English)

    Xie Yan-Wu; Shen Bao-Gen; Sun Ji-Rong

    2008-01-01

    Thermal-annealing has been widely used in modulating the oxygen content of manganites. In this work, we have studied the effect of annealing on the transport properties and magnetoresistance of junctions composed of a La0.9Ca0.1MnO3+δ film and a Nb-doped SrTiO3 substrate. We have demonstrated that the magnetoresistance of junctions is strongly dependent on the annealing conditions: From the junction annealed-in-air to the junction annealed-in-vacuum, the magnetoresistance near 0-V bias can vary from ~-60% to~0. A possible mechanism accounting for this phenomenon is discussed.

  20. Thermal annealing of GaAs concentrator solar cells. [during electron irradiation

    Science.gov (United States)

    Curtis, H. B.; Brinker, D. J.

    1989-01-01

    The thermal annealing of GaAs concentrator cells after electron irradiation is reported. Results are given for cells annealed at 150, 200, and 250 C. Isochronal annealing was done for 20 min intervals up to 350 C. For cells irradiated with electrons of energies between 0.7 and 2.3 MeV, the recovery decreases with increasing electron energy. Isothermal and isochronal annealing produce the same recovery. Cells irradiated to 3 x 10 to the 15th or 1 x 10 to the 16th e/sq cm recover to similar unannealed fractions. Significant annealing is seen starting at 150 C, although very long times are required.

  1. In situ annealing and high-rate silicon epitaxy on porous silicon by mesoplasma process

    Science.gov (United States)

    Zhang, Sheng; Lu, Ziyu; Sheng, Jiang; Gao, Pingqi; Yang, Xi; Wu, Sudong; Ye, Jichun; Kambara, Makoto

    2016-05-01

    By a mesoplasma process, a double-layer porous Si is annealed for a few seconds, by which an annealing effect similar to that of a prolonged conventional annealing process is obtained. The basic annealing process is considered to follow the classical sintering theory. However, the surface of the annealed porous Si is rough with large open voids because of H etching. The epitaxial Si films deposited on such a rough surface at a rate of 350 nm/s show a smooth surface with a low defect density compared with those deposited on a polished Si wafer, which clearly demonstrates the advantages of the cluster-assisted mesoplasma process.

  2. Influences of Annealing on Residual Stress and Structure of HfO2 Films

    Institute of Scientific and Technical Information of China (English)

    SHEN Yan-Ming; SHAO Shu-Ying; DENG Zhen-Xia; HE Hong-Bo; SHAO Jian-Da; FAN Zheng-Xiu

    2007-01-01

    HfO2 films are deposited on BK7 glass substrates by electron beam evaporation. The influences of annealing between 100℃ and 400℃ on residual stresses and structures of HfO2 films are studied. It is found that little differences of spectra, residual stresses and structures are obtained after annealing at lower temperatures. After annealing at higher temperatures, the spectra shift to short wavelength, the residual stress increases with the increasing annealing temperature. At the same time, the crystallite size increases and interplanar distance decreases. The variations of optical spectra and residual stress correspond to the evolutions of structures induced by annealing.

  3. Sensitivity loss of LiF: Mg,Cu,P thermoluminescence dosemeters caused by oven annealing

    International Nuclear Information System (INIS)

    LiF:Mg,Cu,P is a very sensitive thermoluminescence material that can be used for personal dosimetry in radiology. But if this material is heated too much during annealing or reading it quickly loses its sensitivity. This study shows that an annealing oven in wide use can cause thermal damage to the dosemeters owing to inhomogeneous temperature distribution in the annealing tray. At annealing temperatures >240 deg. C, differences of only 1 deg. C lead to significant losses of sensitivity. Therefore, it is necessary to measure the distribution of temperature in the annealing tray for correct placement of the dosemeters in the tray. (authors)

  4. Effect of Nitrogen Partitioning on Yield Strength in Nitrogen-Alloyed Duplex Stainless Steel During Annealing

    Science.gov (United States)

    Jang, Min-Ho; Moon, Joonoh; Lee, Tae-Ho; Park, Seong-Jun; Han, Heung Nam

    2014-04-01

    Nitrogen partitioning and its effect on the yield strength in nitrogen-alloyed duplex stainless steel during annealing were investigated at different annealing temperatures. The decrease in the austenite fraction with an increase in the annealing temperature promoted nitrogen partitioning into austenite. When the nitrogen content in austenite was low, the yield strength decreased with an increase in the annealing temperature due to grain growth, while when it was higher than 0.5 wt pct, the yield strength increased with an increase in the annealing temperature, because the austenite became noticeably hard.

  5. Effects of high magnetic field annealing on the initial recrystallized texture in pure copper

    Science.gov (United States)

    He, Tong; Wang, Yan; Sun, Wei; Zhao, Xiang

    2015-03-01

    The cold-rolled pure copper sheets were annealed with and without a high magnetic field of 12 T. The results showed that the magnetic annealing could promote the formation of the initial recrystallized cube texture. The magnetic annealing did not dramatically change the final annealing textures, but the intensity of the recrystallized cube texture is obviously different. The differences of the recrystallized cube orientation intensity between the specimens with and without the field annealing may be attributed to the effects of the magnetic field on the mobility of grain boundaries.

  6. The tensile behavior and deformation microstructure of cryo-rolled and annealed pure nickel

    International Nuclear Information System (INIS)

    The deformation microstructures of room temperature and cryo-rolled commercially pure nickel to a thickness reduction of 95% were studied by transmission electron microscopy (TEM). Lamellar boundary spacings and boundary misorientations were measured and analyzed. It was found that the only difference between these two microstructures was boundary spacing. After annealed under different annealing conditions, the tensile behaviors of rolled and annealed pure nickel were studied. It was found that the higher the strength after annealing, the lower the ductility. The combination of high strength and high ductility behavior found in copper by cryo-rolling and annealing was not found in the present research

  7. Metallic nanowire networks: effects of thermal annealing on electrical resistance

    Science.gov (United States)

    Langley, D. P.; Lagrange, M.; Giusti, G.; Jiménez, C.; Bréchet, Y.; Nguyen, N. D.; Bellet, D.

    2014-10-01

    Metallic nanowire networks have huge potential in devices requiring transparent electrodes. This article describes how the electrical resistance of metal nanowire networks evolve under thermal annealing. Understanding the behavior of such films is crucial for the optimization of transparent electrodes which find many applications. An in-depth investigation of silver nanowire networks under different annealing conditions provides a case study demonstrating that several mechanisms, namely local sintering and desorption of organic residues, are responsible for the reduction of the systems electrical resistance. Optimization of the annealing led to specimens with transmittance of 90% (at 550 nm) and sheet resistance of 9.5 Ω sq-1. Quantized steps in resistance were observed and a model is proposed which provides good agreement with the experimental results. In terms of thermal behavior, we demonstrate that there is a maximum thermal budget that these electrodes can tolerate due to spheroidization of the nanowires. This budget is determined by two main factors: the thermal loading and the wire diameter. This result enables the fabrication and optimization of transparent metal nanowire electrodes for solar cells, organic electronics and flexible displays.

  8. Maximum-Entropy Inference with a Programmable Annealer

    Science.gov (United States)

    Chancellor, Nicholas; Szoke, Szilard; Vinci, Walter; Aeppli, Gabriel; Warburton, Paul A.

    2016-01-01

    Optimisation problems typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this maximises the likelihood that the solution is correct. The maximum entropy solution on the other hand takes the form of a Boltzmann distribution over the ground and excited states of the cost function to correct for noise. Here we use a programmable annealer for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that finite temperature maximum entropy decoding can give slightly better bit-error-rates than the maximum likelihood approach, confirming that useful information can be extracted from the excited states of the annealer. Furthermore we introduce a bit-by-bit analytical method which is agnostic to the specific application and use it to show that the annealer samples from a highly Boltzmann-like distribution. Machines of this kind are therefore candidates for use in a variety of machine learning applications which exploit maximum entropy inference, including language processing and image recognition. PMID:26936311

  9. Annealing-induced change in quantum dot chain formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K. [Department of Physics and Astronomy, Brigham Young University, Provo UT 84602 (United States); Yang, Haeyeon [Department of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Kim, Dong Jun [IPG Photonics Corporation, Oxford, MA 01540 (United States)

    2014-12-15

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  10. Annealing-induced change in quantum dot chain formation mechanism

    Directory of Open Access Journals (Sweden)

    Tyler D. Park

    2014-12-01

    Full Text Available Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  11. Annealing-induced change in quantum dot chain formation mechanism

    Science.gov (United States)

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K.; Yang, Haeyeon; Kim, Dong Jun

    2014-12-01

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  12. Microstructure Evolution and Grain Growth Kinetics in Annealed Nanocrystalline Chromium

    Energy Technology Data Exchange (ETDEWEB)

    Chojnowski, Grzegorz [Warsaw University; Przenioslo, Radoslaw [Warsaw University; Sosnowska, Izabela [Warsaw University; Bukowski, Mirko [University of Saarbrucken, Saarbrucken, Germany; Natter, Harald [University of Saarbrucken, Saarbrucken, Germany; Hempelmann, Rolf [University of Saarbrucken, Saarbrucken, Germany; Fitch, Andrew [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL

    2007-01-01

    The kinetics of thermal evolution of the microstructure of nanocrystalline chromium (nano-Cr) has been studied by time-resolved synchrotron radiation techniques: high-resolution powder diffraction and small-angle X-ray scattering (SAXS). The as-prepared electrodeposited nano-Cr with average grain size of 27 nm shows the same bcc structure as {alpha}-Cr. The nano-Cr cubic lattice parameter thermal expansion is the same as that of reference polycrystalline {alpha}-Cr. Annealing of nano-Cr at temperatures above 400 C leads to a grain growth process with the final grain size not exceeding 125 nm even at a temperature of 700 C. The single power-law behavior is observed by SAXS in as-prepared nano-Cr changes during annealing above 400 C. In nano-Cr samples annealed at temperatures between 400 and 700 C, the low-q part of the SAXS signal shows a Porod-type behavior while the high-q part shows a power-law Q-{alpha} with the exponent {alpha} < 4. This effect is probably due to changes of the grain surface roughness during grain growth.

  13. Nuclear techniques of analysis in diamond synthesis and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, D. N.; Prawer, S.; Gonon, P.; Walker, R.; Dooley, S.; Bettiol, A.; Pearce, J. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Nuclear techniques of analysis have played an important role in the study of synthetic and laser annealed diamond. These measurements have mainly used ion beam analysis with a focused MeV ion beam in a nuclear microprobe system. A variety of techniques have been employed. One of the most important is nuclear elastic scattering, sometimes called non-Rutherford scattering, which has been used to accurately characterise diamond films for thickness and composition. This is possible by the use of a database of measured scattering cross sections. Recently, this work has been extended and nuclear elastic scattering cross sections for both natural boron isotopes have been measured. For radiation damaged diamond, a focused laser annealing scheme has been developed which produces near complete regrowth of MeV phosphorus implanted diamonds. In the laser annealed regions, proton induced x-ray emission has been used to show that 50 % of the P atoms occupy lattice sites. This opens the way to produce n-type diamond for microelectronic device applications. All these analytical applications utilize a focused MeV microbeam which is ideally suited for diamond analysis. This presentation reviews these applications, as well as the technology of nuclear techniques of analysis for diamond with a focused beam. 9 refs., 6 figs.

  14. Maximum-Entropy Inference with a Programmable Annealer

    Science.gov (United States)

    Chancellor, Nicholas; Szoke, Szilard; Vinci, Walter; Aeppli, Gabriel; Warburton, Paul A.

    2016-03-01

    Optimisation problems typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this maximises the likelihood that the solution is correct. The maximum entropy solution on the other hand takes the form of a Boltzmann distribution over the ground and excited states of the cost function to correct for noise. Here we use a programmable annealer for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that finite temperature maximum entropy decoding can give slightly better bit-error-rates than the maximum likelihood approach, confirming that useful information can be extracted from the excited states of the annealer. Furthermore we introduce a bit-by-bit analytical method which is agnostic to the specific application and use it to show that the annealer samples from a highly Boltzmann-like distribution. Machines of this kind are therefore candidates for use in a variety of machine learning applications which exploit maximum entropy inference, including language processing and image recognition.

  15. Annealing of Silicate Dust by Nebular Shocks at 10 AU

    Science.gov (United States)

    Harker, David E.; Desch, Steven J.; DeVincenzi, D. (Technical Monitor)

    2001-01-01

    Silicate dust grains in the interstellar medium are known to be mostly amorphous, yet crystalline silicate grains have been observed in many long-period comets and in protoplanetary disks. Annealing of amorphous silicate grains into crystalline grains requires temperatures greater than or approximately equal to 1000 K, but exposure of dust grains in comets to such high temperatures is apparently incompatible with the generally low temperatures experienced by comets. This has led to the proposal of models in which dust grains were thermally processed near the protoSun, then underwent considerable radial transport until they reached the gas giant planet region where the long-period comets originated. We hypothesize instead that silicate dust grains were annealed in situ, by shock waves triggered by gravitational instabilities. We assume a shock speed of 5 km/s, a plausible value for shocks driven by gravitational instabilities. We calculate the peak temperatures of pyroxene grains under conditions typical in protoplanetary disks at 5-10 AU. We show that in situ annealing of micron-sized dust grains can occur, obviating the need for large-scale radial transport.

  16. Simulated annealing spectral clustering algorithm for image segmentation

    Institute of Scientific and Technical Information of China (English)

    Yifang Yang; and Yuping Wang

    2014-01-01

    The similarity measure is crucial to the performance of spectral clustering. The Gaussian kernel function based on the Euclidean distance is usual y adopted as the similarity mea-sure. However, the Euclidean distance measure cannot ful y reveal the complex distribution data, and the result of spectral clustering is very sensitive to the scaling parameter. To solve these problems, a new manifold distance measure and a novel simulated anneal-ing spectral clustering (SASC) algorithm based on the manifold distance measure are proposed. The simulated annealing based on genetic algorithm (SAGA), characterized by its rapid conver-gence to the global optimum, is used to cluster the sample points in the spectral mapping space. The proposed algorithm can not only reflect local and global consistency better, but also reduce the sensitivity of spectral clustering to the kernel parameter, which improves the algorithm’s clustering performance. To efficiently ap-ply the algorithm to image segmentation, the Nystr¨om method is used to reduce the computation complexity. Experimental re-sults show that compared with traditional clustering algorithms and those popular spectral clustering algorithms, the proposed algorithm can achieve better clustering performances on several synthetic datasets, texture images and real images.

  17. Direct Immersion Annealing (DIA) of Block Copolymer Thin Film

    Science.gov (United States)

    Modi, Arvind; Karim, Alamgir

    2014-03-01

    Solvent Vapor Annealing (SVA) methodologies of block copolymer (BCP) films have demonstrated excellent potential for control of nanostructures and morphologies. However, SVA designs require sophisticated instrumentation, and fine control of system parameters in batch processing mode which is relatively complex and limits its feasibility. We developed a faster and robust solvent immersion strategy for microphase separation and nanostructure control of as-cast BCP thin films with minimal sophistication. Our Direct Immersion Annealing (DIA) method requires immersion in a mixture of non-solvent and good solvent (for BCP) for annealing. A non-solvent component prevents dissolution of the film resting on substrate while a good solvent percolates through the film, plasticizes it, and shifts glass-transition below room temperature leading to microphase separation and ordering. Our study of PS-PMMA system demonstrates that a robust control over thin film ordering and transient swelling could be achieved through a fine control of solubility parameter of solvent mixture and temperature with no dead-time. Further, we exhibit the utility of DIA for alignment of BCP domains on topographically patterned substrates. University of Akron Research Foundation (UARF).

  18. Correlation of annealing with chemical stability in lyophilized pharmaceutical glasses.

    Science.gov (United States)

    Luthra, Suman A; Hodge, Ian M; Utz, Marcel; Pikal, Michael J

    2008-12-01

    This research constitutes a thorough study of the relationship between the chemical stability, aging state and global molecular motion on the one hand, and microscopic local mobility in multi-component systems on the other hand. The objective of the present work was to determine whether annealing a glass below T(g) affects its chemical stability and determine if the rate of chemical degradation couples with global relaxation times determined using calorimetery, and/or with T(1) and T(1rho) relaxation times measured using ssNMR. Model compounds chosen for this research were lyophilized aspartame/sucrose and aspartame/trehalose (1:10 w/w) formulations. The chemical degradation was assessed at various temperatures using high-performance liquid chromatography (HPLC) to determine the impact of annealing on chemical stability. The rate constant for chemical degradation was estimated using stretched time kinetics. The results support the hypothesis that thermal history affects the molecular mobility required for structural relaxation and such effect is critical for chemical stability, that is, a stabilization effect upon annealing is observed. PMID:18481306

  19. Annealing-induced change in quantum dot chain formation mechanism

    International Nuclear Information System (INIS)

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier

  20. Soft magnetic thin films: influence of annealing on magnetic properties

    International Nuclear Information System (INIS)

    Soft magnetic materials are currently used in a variety of applications in electrical machines, sensors and elements of devices. If prepared in thin film form, they can be applied to micro- and nano-patterned devices. However, with respect to ribbons and bulk materials, thin films of the same composition usually display worse soft magnetic properties, thus requiring suitable solutions to restore high permeability and low coercivity. In this review, the magnetic properties of thin films prepared by sputtering are presented. Several compositions of soft magnetic materials are investigated, including Co-Fe-Si-B, Fe-Cu-Nb-Si-B, Fe-Si-B, Fe-Co-Nb-Si-P-B, Fe-Zr-Nb-Cu-B. Their amorphous-to-crystallization processes are studied by means of furnace annealing and Joule heating. Hysteresis loops and magnetic domain imaging, together with structural techniques, are used to follow the effects of annealing, which include stress relaxation and crystallization. The effects of magnetic field annealing are investigated and discussed.

  1. Reactor controller design using genetic algorithms with simulated annealing

    International Nuclear Information System (INIS)

    This chapter presents a digital control system for ITU TRIGA Mark-II reactor using genetic algorithms with simulated annealing. The basic principles of genetic algorithms for problem solving are inspired by the mechanism of natural selection. Natural selection is a biological process in which stronger individuals are likely to be winners in a competing environment. Genetic algorithms use a direct analogy of natural evolution. Genetic algorithms are global search techniques for optimisation but they are poor at hill-climbing. Simulated annealing has the ability of probabilistic hill-climbing. Thus, the two techniques are combined here to get a fine-tuned algorithm that yields a faster convergence and a more accurate search by introducing a new mutation operator like simulated annealing or an adaptive cooling schedule. In control system design, there are currently no systematic approaches to choose the controller parameters to obtain the desired performance. The controller parameters are usually determined by test and error with simulation and experimental analysis. Genetic algorithm is used automatically and efficiently searching for a set of controller parameters for better performance. (orig.)

  2. Effect of Annealing Atmosphere on the Mechanical Property of Free-cutting Phosphor Bronze Alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The present work is focused on the influence of annealing atmosphere on the microstructure and mechanical property of free-cutting phosphor bronze alloy. The annealing of the alloy was conducted in the three kinds of annealing atmosphere such as air, vacuum and nitrogen. After annealing, a discernable difference in recystallized grain size and lead particle size was not appeared with different annealing atmosphere. The tensile strength of the alloy annealed in air or nitrogen atmosphere was higher than that of those annealed in vacuum atmosphere. In thecase of the alloy annealed in vacuum atmosphere, the mechanical strength was reduced by vaporization of zinc. In the case of annealing in nitrogen and in air atmosphere, the sweating of lead was occurred. However, the inverse segregation of lead was suppressed by copper oxide layer on the surface annealed in air. This copper oxide layer leads to a decrease of the yield during fabrication process. Therefore, annealing of the alloy in nitrogen atmosphere is favorable in terms of the mechanical strength and yield.

  3. Annealing induced reorientation of crystallites in Sn doped ZnO films

    Science.gov (United States)

    Ravichandran, K.; Vasanthi, M.; Thirumurugan, K.; Sakthivel, B.; Karthika, K.

    2014-11-01

    Tin doped ZnO thin films were prepared by employing a simplified spray pyrolysis technique using a perfume atomizer and subsequently annealed under different temperatures from 350 °C to 500 °C in steps of 50 °C. The structural, optical, electrical, photoluminescence and surface morphological properties of the as-deposited films were studied and compared with that of the annealed films. The X-ray diffraction studies showed that as-deposited film exhibits preferential orientation along the (0 0 2) plane and it changes in favour of (1 0 0) plane after annealing. The increase in crystallite size due to annealing is explained on the basis of Ostwald ripening effect. It is found that the optical transmittance and band gap increases with increase in annealing temperature. A slight decrease in resistivity caused by annealing is discussed in correlation with annealing induced defect modifications and surface morphology.

  4. Heavy Tails in the Distribution of Time to Solution for Classical and Quantum Annealing.

    Science.gov (United States)

    Steiger, Damian S; Rønnow, Troels F; Troyer, Matthias

    2015-12-01

    For many optimization algorithms the time to solution depends not only on the problem size but also on the specific problem instance and may vary by many orders of magnitude. It is then necessary to investigate the full distribution and especially its tail. Here, we analyze the distributions of annealing times for simulated annealing and simulated quantum annealing (by path integral quantum Monte Carlo simulation) for random Ising spin glass instances. We find power-law distributions with very heavy tails, corresponding to extremely hard instances, but far broader distributions-and thus worse performance for hard instances-for simulated quantum annealing than for simulated annealing. Fast, nonadiabatic, annealing schedules can improve the performance of simulated quantum annealing for very hard instances by many orders of magnitude. PMID:26684103

  5. Enhanced remanence in flash-annealed Nd4Fe78B18

    International Nuclear Information System (INIS)

    Nanocrystalline Nd4Fe78B18 was produced by affixing current leads directly to amorphous ribbons for flash-annealing. Ribbons were annealed in the range Ta = 650--1,000 C, for times 10--600 s. Flash-annealed ribbons show higher remanence ratios (Mr/Ms ≅ 0.83) than those submitted to conventional furnace (680 C/10 min) annealing (Mr/Ms ≅ 0.74). In flash-annealed ribbons, Moessbauer spectroscopy and x-ray diffraction indicated the presence of the Nd2Fe23B3 phase, in addition to Fe3B, Nd2Fe14B, and α-Fe. Flash-annealing for short times at high temperatures may give Hc values up to 20% higher than furnace annealing. The isothermal remanent magnetization and the dc demagnetization remanence were found to be in reasonable agreement with the Wohlfarth relation

  6. Mechanism for accurate, protein-assisted DNA annealing by Deinococcus radiodurans DdrB.

    Science.gov (United States)

    Sugiman-Marangos, Seiji N; Weiss, Yoni M; Junop, Murray S

    2016-04-19

    Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing. PMID:27044084

  7. Laser annealing and defect study of chalcogenide photovoltaic materials

    Science.gov (United States)

    Bhatia, Ashish

    Cu(In,Ga)Se2 (CIGSe), CuZnSn(S,Se)4(CZTSSe), etc., are the potential chalcogenide semiconductors being investigated for next-generation thin film photovoltaics (TFPV). While the champion cell efficiency of CIGSe has exceeded 20%, CZTSSe has crossed the 10% mark. This work investigates the effect of laser annealing on CISe films, and compares the electrical characteristics of CIGSe (chalcopyrite) and CZTSe (kesterite) solar cells. Chapter 1 through 3 provide a background on semiconductors and TFPV, properties of chalcopyrite and kesterite materials, and their characterization using deep level transient spectroscopy (DLTS) and thermal admittance spectroscopy (TAS). Chapter 4 investigates electrochemical deposition (nonvacuum synthesis) of CISe followed by continuous wave laser annealing (CWLA) using a 1064 nm laser. It is found that CWLA at ≈ 50 W/cm2 results in structural changes without melting and dewetting of the films. While Cu-poor samples show about 40% reduction in the full width at half maximum of the respective x-ray diffraction peaks, identically treated Cu-rich samples register more than 80% reduction. This study demonstrates that an entirely solid-phase laser annealing path exists for chalcopyrite phase formation and crystallization. Chapter 5 investigates the changes in defect populations after pulse laser annealing in submelting regime of electrochemically deposited and furnace annealed CISe films. DLTS on Schottky diodes reveal that the ionization energy of the dominant majority carrier defect state changes nonmonotonically from 215+/-10 meV for the reference sample, to 330+/-10 meV for samples irradiated at 20 and 30 mJ/cm2, and then back to 215+/-10 meV for samples irradiated at 40 mJ/cm2. A hypothesis involving competing processes of diffusion of Cu and laser-induced generation of In vacancies may explain this behavior. Chapter 6 compares the electrical characteristics of chalcopyrite and kesterite materials. Experiments reveal CZTSe cell has an

  8. Influence of initial annealing on structure evolution and magnetic properties of 3.4% Si non-oriented steel during final annealing

    Energy Technology Data Exchange (ETDEWEB)

    Simões Mendanha Pedrosa, Josiane [Department of Physics, Federal University of Ouro Preto, Ouro Preto MG-3540000 (Brazil); Costa Paolinelli, Sebastião da [Research Department Aperam South America, Praça Primeiro de Maio, 9, Timóteo MG-35180018 (Brazil); Barros Cota, André, E-mail: abcota@ufop.br [Department of Physics, Federal University of Ouro Preto, Ouro Preto MG-3540000 (Brazil)

    2015-11-01

    The effect of the initial annealing on structure evolution and magnetic properties during the final annealing of a 3.4% Si non-oriented grain steel was evaluated. Half of the samples were submitted to initial annealing at 1030 °C before cold rolling and all samples were subjected to final annealing process at temperatures from 540 °C to 1100 °C. The magnetic induction and core loss in the final samples, the microstructure by optical microscopy and the crystallographic texture by X-ray diffraction and EBSD were evaluated. The results show that the samples without initial annealing presented better magnetic properties than the samples with initial annealing, due to the higher ratio between Eta fiber and Gamma fiber volume fractions (Eta/Gamma ratio) in their structure after final annealing. - Highlights: • Texture and magnetic properties of 3.4% Si non-oriented electrical steel were measured. • Without initial annealing, better texture and magnetic properties were obtained. • Good texture and magnetic properties are obtained with Steckel hot band structure.

  9. Remarkably improved field emission of TiO2 nanotube arrays by annealing atmosphere engineering

    International Nuclear Information System (INIS)

    Highlights: • TNAs were prepared by anodization and annealed in different atmospheres. • The crystal structure and electronic properties of the prepared TNAs were investigated. • The field emission of TNAs was highly dependent on annealing atmosphere. • A low turn-on of 2.44 V/μm was obtained for TNAs annealed in H2 atmosphere. - Abstract: Highly ordered TiO2 nanotube arrays (TNAs) were prepared by anodization, and followed by annealing in the atmospheres of Air, Vacuum, Ar, and H2. The effect of annealing atmosphere on the crystal structure, composition, and electronic properties of TNAs were systematically investigated. Raman and EDS results indicated that the TNAs annealed in anaerobic atmospheres contained more oxygen vacancies, which result in the substantially improved electron transport properties and reduced work function. Moreover, it was found that the FE properties of TNAs were highly dependent on the annealing atmosphere. By engineering the annealing atmosphere, the turn-on field as low as 2.44 V/μm can be obtained from TNAs annealed in H2, which was much lower than the value of 18.23 V/μm from the TNAs annealed in the commonly used atmosphere of Air. Our work suggests an instructive and attractive way to fabricate high performance TNAs field emitters

  10. MICROSTRUCTURE AND PROPERTIES OF ANNEALED ZnO THIN FILMS DEPOSITED BY MAGNETRON SPUTTERING

    Institute of Scientific and Technical Information of China (English)

    J. Lee; W. Gao; Z. Li; M. Hodgson; A. Asadov; J. Metson

    2005-01-01

    ZnO thin films were deposited on a glass substrate by dc (direct current) and rf (radio frequency) magnetron sputtering. Post-deposition annealing was performed in different atmospheres and at different temperatures. The correlation of the annealing conditions with the microstructure and properties of the ZnO films were investigated by ultraviolet-visible spectroscopy, X-ray diffraction, conductivity measurement and scanning electron microscopy. Only the strong 002peak could be observed by X-ray diffraction. The post-deposition annealing of ZnO films was found to alter the film's microstructure and properties, including crystallinity, porosity, grain size, internal stress level and resistivity. It was also found that after annealing, the conductivity of poorly conductive samples often improved. However, annealing does not improve the conductivity of samples with high conductivity prior to annealing. The resistivity of as-grown films annealing on the conductivity of ZnO, it is believed that annealing may alter the presence and distribution of oxygen defects, reduce the lattice stress, cause diffusion, grain coarsening and recrystallization. Annealing will reduce the density of grain boundaries in less dense films,which may decrease the resistivity of the films. On the other hand, annealing may also increase the porosity of thin films, leading to an increase in resistivity.

  11. Microstructure and mechanical properties of annealed SUS 304H austenitic stainless steel with copper

    International Nuclear Information System (INIS)

    Research highlights: → SUS 304H austenitic stainless steel containing 3 wt.% Cu was annealed at 700 deg. C for up to 100 h. → Microstructure and mechanical properties of annealed alloys are examined. → Nano-sized Cu-rich precipitation upon annealing. → Strength of the alloy remains invariant with annealing whereas ductility improves. → Fatigue crack growth threshold of 3 wt.% Cu added alloy increases with annealing. - Abstract: An experimental investigation into the effect of Cu on the mechanical properties of 0 and 3 wt.% Cu added SUS 304H austenitic stainless steel upon annealing at 700 deg. C for up to 100 h was conducted. Optical microscopy reveals grain coarsening in both the alloys upon annealing. Observations by transmission electron microscopy revealed the precipitation of nanometer-sized spherical Cu particles distributed within the austenitic grains and the presence of carbides at the dislocations. Both the yield and ultimate tensile strengths of the alloys were found to remain invariant with annealing. Tensile ductility and the threshold stress intensity factor range for fatigue crack growth for 3 wt.% Cu added alloy increase with annealing. These are attributed to the grain coarsening with annealing. In all, the addition of Cu to SUS 304H does not affect the mechanical performance adversely while improving creep resistance.

  12. Effect of annealing in hydrogen atmosphere on ZnO films for field emission display

    Science.gov (United States)

    Zulkifli, Zurita; Sharma, Subash; Shinde, Sachin; Kalita, Golap; Tanemura, M.

    2015-11-01

    Surface morphology, crystallinity, conductivity and optical transmittance of ZnO films can be modified by annealing process. Hydrogen is one of the popular annealing gases as well as nitrogen, argon, oxygen and air which are commonly used for thin film cleaning or the removal of native oxide. In general, annealing is done at high temperatures (> 600degC) to improve the film properties. From a view point of environment, however, lower annealing temperature is preferable. In this work, low annealing process was challenged to understand the effect of annealing temperature on properties of ZnO thin films and nanostructured film grown on glass substrates for transparent field emission device applications. The annealing temperature employed was 100, 200 and 450°C at 100 sccm hydrogen flow rate. ZnO thin films were deposited by RF magnetron sputtering. The ZnO thin films were characterized by X-ray diffraction analysis (XRD), Atomic Force Microscopy (AFM), UV-VIS and Raman spectroscopy. The sheet resistances reduced about 15 kohm/sq at low annealing temperature. By contrast, the optical transmittance did not show any significant changes after annealing. The FE current density increased after the ZnO nanostructures film was annealed in 100°C. The results obtained could motivate a surface treatment for flexible ZnO thin film since the substrate is always suffered by heat.

  13. Sputtered lead scandium tantalate thin films: crystallization behaviour during post-deposition annealing

    International Nuclear Information System (INIS)

    Lead scandium titanate (PST) thin films were deposited by RF dual magnetron sputtering and then annealed either by vacuum furnace or combined rapid thermal annealing (RTA) and furnace anneal. The film structure was investigated by x-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy techniques. Lead loss was more severe using furnace annealing than the combined RTA and furnace anneal. The annealed films were characterized by the presence of voids and exhibited relaxor ferroelectric characteristics. PST perovskite crystal grains were found to co-exist with pyrochlore matrix in the furnace-only annealed films, whilst in RTA annealed films no apparent pyrochlore morphology was observed in the TEM image. Lead was found to diffuse through the bottom electrode Pt layer during the annealing. Films treated by combining RTA and furnace annealing have shown pyroelectric coefficients under field of up to 500 μC m-2 K-1, a dielectric loss of below 0.007 and a merit figure for thermal detection of 2.5x10-5 Pa-1/2. (author)

  14. Remarkably improved field emission of TiO{sub 2} nanotube arrays by annealing atmosphere engineering

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Ai-Zhen; Wang, Cheng-Wei, E-mail: cwwang@nwnu.edu.cn; Chen, Jian-Biao; Zhang, Xu-Qiang; Li, Yan; Wang, Jian

    2015-10-15

    Highlights: • TNAs were prepared by anodization and annealed in different atmospheres. • The crystal structure and electronic properties of the prepared TNAs were investigated. • The field emission of TNAs was highly dependent on annealing atmosphere. • A low turn-on of 2.44 V/μm was obtained for TNAs annealed in H{sub 2} atmosphere. - Abstract: Highly ordered TiO{sub 2} nanotube arrays (TNAs) were prepared by anodization, and followed by annealing in the atmospheres of Air, Vacuum, Ar, and H{sub 2}. The effect of annealing atmosphere on the crystal structure, composition, and electronic properties of TNAs were systematically investigated. Raman and EDS results indicated that the TNAs annealed in anaerobic atmospheres contained more oxygen vacancies, which result in the substantially improved electron transport properties and reduced work function. Moreover, it was found that the FE properties of TNAs were highly dependent on the annealing atmosphere. By engineering the annealing atmosphere, the turn-on field as low as 2.44 V/μm can be obtained from TNAs annealed in H{sub 2}, which was much lower than the value of 18.23 V/μm from the TNAs annealed in the commonly used atmosphere of Air. Our work suggests an instructive and attractive way to fabricate high performance TNAs field emitters.

  15. Flash annealing and magnetic interactions in Pr4 Fe78 B18

    International Nuclear Information System (INIS)

    Enhanced-remanence Pr4 Fe78 B18 alloys were produced by using a high heating rate/short time anneal, the so-called flash annealing process. Partially amorphous ribbons were produced by melt spinning and then annealed for 10-20 s at temperatures 600-820 deg C by passing current through the sample. Coercivity increases of up to 15% were 820 deg C by passing current through the sample. Coercivity increases of up to 15% were systematically observed in relation to furnace-annealed material. Our best flash annealed material (600 deg C/20 s) had Hc = 3.5 k O e, Mr/Ms = 0.77,and (B H)max 11.1 M G O e. Hc was found to be relatively insensitive to annealing time or temperature. Good coupling between the magnetic phases was obtained at lower annealing temperatures and for initially more amorphous material, while loop squareness was improved somewhat by longer anneals. The magnetic remanence curves Mr(H), obtained for different initial demagnetized states (thermal, ac, dc+, dc-), and the remanence Md(H), obtained for an initially saturated state, were determined for the construction of Henkel plots (HP). The HP for ac-demagnetized Pr4 Fe78 B18 shows both magnetizing and demagnetizing interactions. However, there is no significant difference between the HP of flash annealed and furnace annealed samples. (author)

  16. Formation of oxygen related donors in step-annealed CZ–silicon

    Indian Academy of Sciences (India)

    Vikash Dubey; Shyam Singh

    2002-12-01

    The effect of step-annealing necessitated by the difficulties being faced in the long duration annealing treatments to be given to CZ–silicon has been studied. One pre-anneal of 10 h followed by annealing of 10 h causes a decrease in the absorption coefficient for carbon (c). Oxygen and carbon both accelerate thermal donor (TD) formation process but oxygen plays a dominating role. Three anneals of 10 h each followed by one anneal of 10 h support the view that carbon suppresses the donor formation. The absorption coefficient for carbon decreases after a few number of step-anneals resulting in the transformation of TD to new donor (ND) as brought about by annealing at temperature, > 500°C. It is quite logical to conclude that step-annealing may bring about the same results as obtained on continuous annealing for a longer duration. The results have been fully supported by proper interpretation in the light of existing theories.

  17. The influence of post-deposition annealing upon amorphous silicon/crystalline silicon heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mikolášek, Miroslav, E-mail: miroslav.mikolasek@stuba.sk [Slovak University of Technology, Faculty of Electrical Engineering and Information Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); Nemec, Michal; Kováč, Jaroslav [Slovak University of Technology, Faculty of Electrical Engineering and Information Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); Foti, Marina; Gerardi, Cosimo [IMS-R and D, STMicroelectronics, Stradale Primosole, 50, 95121 Catania (Italy); Mannino, Giovanni; Valenti, Luca; Lombardo, Salvatore [CNR-IMM, Zona Industriale, Ottava Strada, 5, 95121 Catania (Italy)

    2014-11-15

    Highlights: • We studied the impact of the thermal annealing on the silicon heterojunction solar cells. • Compared were samples deposited by ICP-CVD and PE-CVD methods. • Annealing up to 250 °C improves output performance of both solar cells. • Annealing above 250 °C increases defect states density at the interface and in the amorphous emitter. • Samples deposited by ICP-CVD shows better resistance against annealing. - Abstract: This paper presents a comparative study of the influence of post-deposition annealing on amorphous silicon/crystalline silicon heterojunction solar cells deposited by ICP-CVD and PE-CVD techniques. Two major effects on the solar cell efficiency occur caused by thermal annealing. The first effect is a slight improvement of the performance on annealing up to 250 °C. The second effect, for annealing temperatures above 250 °C, reveals deterioration of the solar cell performance. It is suggested that both effects are related to thermally activated diffusion of hydrogen. For low annealing temperatures, diffusion of weakly bonded hydrogen allows to passivate the defects in the amorphous emitter and at the heterointerface. In the high temperature annealing region, outdiffusion of hydrogen is assumed to be responsible for an increase of defect states in the structures. The results indicate a better stability after high temperature treatment for the sample prepared by ICP-CVD technology.

  18. Silicon nanoparticle synthesis by short-period thermal anneals at atmospheric pressure in argon

    International Nuclear Information System (INIS)

    Silicon nanoparticles have been studied for a wide variety of applications including nanoelectronic, photovoltaic, and optoelectronic devices. In this work, silicon nanoparticles were synthesized by short-period annealing of silicon-on-insulator substrates to temperatures ranging between 600 and 900 deg. C in argon gas at atmospheric pressure. Two different top silicon layers were deposited by ion-beam sputtering onto oxidized substrates. The thinner 6 nm top layer samples were annealed to temperatures for 30 s periods while thicker 15 nm top layer samples were annealed for 60 s periods. For both sets of samples, nanoparticles were observed to form at all the anneal temperatures through imaging by AFM. One long-period UHV anneal study, with 30-min anneal times, observed nanoparticle formation at temperatures similar to the current work while another similar long-period UHV anneal reported nanoparticle formation only above well-defined formation temperatures that depended upon the starting top layer thickness. In the current work, the average nanoparticle radius was found to increase both with the final anneal temperature and anneal period. For the highest anneal temperatures of the 6 nm top layer samples, a changing surface topography indicated that the thinner Si source layer was becoming depleted and the nanoparticle formation process was nearing completion. No such changes were observed for the thicker 15 nm samples at the same temperatures.

  19. Reduced-Complexity Deterministic Annealing for Vector Quantizer Design

    Directory of Open Access Journals (Sweden)

    Ortega Antonio

    2005-01-01

    Full Text Available This paper presents a reduced-complexity deterministic annealing (DA approach for vector quantizer (VQ design by using soft information processing with simplified assignment measures. Low-complexity distributions are designed to mimic the Gibbs distribution, where the latter is the optimal distribution used in the standard DA method. These low-complexity distributions are simple enough to facilitate fast computation, but at the same time they can closely approximate the Gibbs distribution to result in near-optimal performance. We have also derived the theoretical performance loss at a given system entropy due to using the simple soft measures instead of the optimal Gibbs measure. We use thederived result to obtain optimal annealing schedules for the simple soft measures that approximate the annealing schedule for the optimal Gibbs distribution. The proposed reduced-complexity DA algorithms have significantly improved the quality of the final codebooks compared to the generalized Lloyd algorithm and standard stochastic relaxation techniques, both with and without the pairwise nearest neighbor (PNN codebook initialization. The proposed algorithms are able to evade the local minima and the results show that they are not sensitive to the choice of the initial codebook. Compared to the standard DA approach, the reduced-complexity DA algorithms can operate over 100 times faster with negligible performance difference. For example, for the design of a 16-dimensional vector quantizer having a rate of 0.4375 bit/sample for Gaussian source, the standard DA algorithm achieved 3.60 dB performance in 16 483 CPU seconds, whereas the reduced-complexity DA algorithm achieved the same performance in 136 CPU seconds. Other than VQ design, the DA techniques are applicable to problems such as classification, clustering, and resource allocation.

  20. Optimisation of electron beam characteristics by simulated annealing

    International Nuclear Information System (INIS)

    Full text: With the development of technology in the field of treatment beam delivery, the possibility of tailoring radiation beams (via manipulation of the beam's phase space) is foreseeable. This investigation involved evaluating a method for determining the characteristics of pure electron beams which provided dose distributions that best approximated desired distributions. The aim is to determine which degrees of freedom are advantageous and worth pursuing in a clinical setting. A simulated annealing routine was developed to determine optimum electron beam characteristics. A set of beam elements are defined at the surface of a homogeneous water equivalent phantom defining discrete positions and angles of incidence, and electron energies. The optimal weighting of these elements is determined by the (generally approximate) solution to the linear equation, Dw = d, where d represents the dose distribution calculated over the phantom, w the vector of (50 - 2x104) beam element relative weights, and D a normalised matrix of dose deposition kernels. In the iterative annealing procedure, beam elements are randomly selected and beam weighting distributions are sampled and used to perturb the selected elements. Perturbations are accepted or rejected according to standard simulated annealing criteria. The result (after the algorithm has terminated due to meeting an iteration or optimisation specification) is an approximate solution for the beam weight vector (w) specified by the above equation. This technique has been applied for several sample dose distributions and phase space restrictions. An example is given of the phase space obtained when endeavouring to conform to a rectangular 100% dose region with polyenergetic though normally incident electrons. For regular distributions, intuitive conclusions regarding the benefits of energy/angular manipulation may be made, whereas for complex distributions, variations in intensity over beam elements of varying energy and

  1. U-Mo Plate Blister Anneal Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    Francine J. Rice; Daniel M. Wachs; Adam B. Robinson; Dennis D. Keiser Jr.; Jan-Fong Jue; Danielle M. Perez; Ross Finlay

    2010-10-01

    Blister thresholds in fuel elements have been a longstanding performance parameter for fuel elements of all types. This behavior has yet to be fully defined for the RERTR U-Mo fuel types. Blister anneal studies that began in 2007 have been expanded to include plates from more recent RERTR experiments. Preliminary data presented in this report encompasses the early generations of the U-Mo fuel systems and the most recent but still developing fuel system. Included is an overview of relevant dispersion fuel systems for the purposes of comparison.

  2. Recovery of the irradiated JFETs by thermal annealing

    International Nuclear Information System (INIS)

    Study about the recovering of irradiated JFET transistors has been reported. The JFETs were damaged totally or partially by exposition to Gamma ray and neutrons. Electronics noise has used to evaluate the effect of radiation and the recovery. The study focused on the recovery by thermal annealing, where samples have been heated gradually until 140 centigrade degree (410 K). The recovery ratio given by this method was higher than that resulted from the relaxation method (time recovery) carried out in the room temperature (300 K), especially for Gamma irradiated samples.(author)

  3. Radiation damage and annealing of amorphous silicon solar cells

    Science.gov (United States)

    Byvik, C. E.; Slemp, W. S.; Smith, B. T.; Buoncristiani, A. M.

    1984-01-01

    Amorphous silicon solar cells were irradiated with 1 MeV electrons at the Space Environmental Effects Laboratory of the NASA Langley Research Center. The cells accumulated a total fluence of 10 to the 14th, 10 to the 15th, and 10 to the 16th electrons per square centimeter and exhibited increasing degradation with each irradiation. This degradation was tracked by evaluating the I-V curves for AM0 illumination and the relative spectral response. The observed radiation damage was reversed following an anneal of the cells under vacuum at 200 C for 2 hours.

  4. Laser annealing of thin film polycrystalline silicon solar cell

    Directory of Open Access Journals (Sweden)

    Chowdhury A.

    2013-11-01

    Full Text Available Performances of thin film polycrystalline silicon solar cell grown on glass substrate, using solid phase crystallization of amorphous silicon can be limited by low dopant activation and high density of defects. Here, we investigate line shaped laser induced thermal annealing to passivate some of these defects in the sub-melt regime. Effect of laser power and scan speed on the open circuit voltage of the polysilicon solar cells is reported. The processing temperature was measured by thermal imaging camera. Enhancement of the open circuit voltage as high as 210% is achieved using this method. The results are discussed.

  5. Radiation annealing of reactor graphite after neutron irradiation

    International Nuclear Information System (INIS)

    The reactor graphite specimens initially irradiated at 310-450 K by the fluences 5x1021, 9x1021, 1,3x1022 n/sm2 (E>0,18 MeV) were repeatedly irradiated at 620-1200 K by the fluences up to 2,5x1021 n/sm2. Simultaneously the control specimens of reactor graphite and nongraphitized half finished product were irradiated. It is shown that irradiation annealing of preirradiated specimens leads to the more considerable shrinkage that of the control specimens

  6. U-Mo Plate Blister Anneal Interim Report

    International Nuclear Information System (INIS)

    Blister thresholds in fuel elements have been a longstanding performance parameter for fuel elements of all types. This behavior has yet to be fully defined for the RERTR U-Mo fuel types. Blister anneal studies that began in 2007 have been expanded to include plates from more recent RERTR experiments. Preliminary data presented in this report encompasses the early generations of the U-Mo fuel systems and the most recent but still developing fuel system. Included is an overview of relevant dispersion fuel systems for the purposes of comparison.

  7. A simplistic model for reverse annealing in irradiated silicon

    International Nuclear Information System (INIS)

    Based on the experimental results of systematic studies on radiation damage by several groups, a model is presented which is able to explain some puzzles as the apparent absence of type inversion near the silicon surface of strongly irradiated detectors and the continuing functioning of n-type silicon detectors after type inversion. As a consequence of this model a new method for suppressing reverse annealing is proposed. This method at the same time would strongly reduce doping changes due to irradiation and also diminish the reverse bias current. It thus could significantly increase the radiation hardness of silicon detectors. (orig.)

  8. Structural defects in laser- and electron-beam annealed silicon

    International Nuclear Information System (INIS)

    Laser and electron beam pulses provide almost an ideal source of heat by which thin layers of semiconductors can be rapidly melted and solidified with heating and cooling rates exceeding 1080C/sec. Microstructural modifications obtained as a function of laser parameters are examined and it is shown that both laser and electron beam pulses can be used to remove displacement damage, dislocations, dislocation loops and precipitates. Annealing of defects underneath the oxide layers in silicon is possible within a narrow energy window. The formation of cellular structure provides a rather clear evidence of melting which leads to segregation and supercooling, and subsequent cell formation

  9. Annealing effects on the structure and electrical characteristics of amorphous Er2O3 films

    Institute of Scientific and Technical Information of China (English)

    Fang Ze-Bo; Zhu Yan-Yan; Wang Jia-Le; Jiang Zui-Min

    2009-01-01

    Amorphous Er2O3 films are deposited on Si (001) substrates by using reactive evaporation.This paper reports the evolution of the structure,morphology and electrical characteristics with annealing temperatures in an oxygen ambience.X-ray diffraction and high resolution transimission electron microscopy measurement show that the films remain amorphous even after annealing at 700℃.The capacitance in the accumulation region of Er2O3 films annealed at 450℃ is higher than that of as-deposited films and films annealed at other temperatures.An Er2O3/ErOx/SiOx/Si structure model is proposed to explain the results.The annealed films also exhibit a low leakage current density (around 1.38×10-4 A/cm2 at a bias of -1V) due to the evolution of morphology and composition of the films after they are annealed.

  10. Fe48Co52 Alloy Nanowire Arrays: Effects of Magnetic Field Annealing

    Institute of Scientific and Technical Information of China (English)

    Hai-lin Sua; Shao-long Tang; Rui-long Wang; Yi-qing Chen; Chong Jia; You-wei Du

    2009-01-01

    The effects of magnetic field annealing on the properties of Fe48Co52 alloy nanowire arrays with various interwire distances (Di=30-60 nm) and wire diameters (Dw=22-46 nm) were investigated in detail. It was found that the array's best annealing temperature and crys-talline structure did not show any apparent dependence on the treatment of applying a 3 kOe magnetic field along the wire during the annealing process. For arrays with small Dw or with large Di, the treatment of magnetic field annealing also had no obvious influence on their magnetic performances. However, such a magnetic field annealing constrained the shift of the easy magnetization direction and improved the coercivity and the squareness obviously for arrays with large Dw or with small Di. The difference in the intensity of the effective anisotropic field within the arrays was believed to be responsible for this different variation of the array's magnetic properties after magnetic field annealing.

  11. Effects of Rapid Recurrent Thermal Annealing on Giant Magnetoresistance NiFe/Ag Multilayers

    Institute of Scientific and Technical Information of China (English)

    文岐业; 张怀武; 蒋向东; 唐晓莉; 张万里

    2003-01-01

    NiFe/Ag multilayers were prepared by dc sputtering onto glass-ceramic substrates directly at room temperature.The samples were thermally processed by rapid recurrent thermal anneal (RRTA). We studied the effects of RRTA on giant magnetoresistance (GMR) NiFe/Ag multilayer by controlling the anneal temperature as well as the rapid anneal cycle. The samples after three RRTA cycles have a similar annealing temperature dependence of GMR responses to the ordinary annealed samples. With the increasing anneal cycle, the GMR response improved at first and then reached an unexpected high value of 9% before descent rapidly. Microstructure study shows that this effect is ascribed to the transformation of continuous NiFe layer into discontinuous one, and then into a granular like film in a step-by-step way.

  12. Rapid thermal annealing and crystallization mechanisms study of silicon nanocrystal in silicon carbide matrix

    Directory of Open Access Journals (Sweden)

    Wan Zhenyu

    2011-01-01

    Full Text Available Abstract In this paper, a positive effect of rapid thermal annealing (RTA technique has been researched and compared with conventional furnace annealing for Si nanocrystalline in silicon carbide (SiC matrix system. Amorphous Si-rich SiC layer has been deposited by co-sputtering in different Si concentrations (50 to approximately 80 v%. Si nanocrystals (Si-NC containing different grain sizes have been fabricated within the SiC matrix under two different annealing conditions: furnace annealing and RTA both at 1,100°C. HRTEM image clearly reveals both Si and SiC-NC formed in the films. Much better "degree of crystallization" of Si-NC can be achieved in RTA than furnace annealing from the research of GIXRD and Raman analysis, especially in high-Si-concentration situation. Differences from the two annealing procedures and the crystallization mechanism have been discussed based on the experimental results.

  13. Ion implantation induced defects in 6H-SiC and their annealing behaviour

    International Nuclear Information System (INIS)

    Fourfold Al+ implantations into 6H-SiC have been carried out in order to create a laterally structured p-doped layer. This way, a 400 nm thick box-shaped Al profile with a concentration plateau of 5 x 1019 cm-3 buried 200 nm below the SiC surface could be realized. The defects caused by the ion implantation should be minimized by implantation at higher substrate temperatures and post implantation annealing. In addition to the traditional furnace annealing a flash lamp annealing has been used. The defect structure after implantation and annealing has been investigated by slow positron implantation spectroscopy (SPIS). It could be shown that vacancies and vacancy agglomerates can be removed using furnace annealing at 1650 C. However, dislocation loops in the implantation region remain stable at this temperature. Using flash lamp annealing a further defect removal could be observed. (orig.)

  14. Thermal annealing as a method to predict results of high temperature irradiation embrittlement

    International Nuclear Information System (INIS)

    In order to assess the validity of post-irradiation annealing as a method to predict results of high temperature irradiation a new analysis of experimental data has been performed revealing the combined influence of annealing temperature and impurities content on residual embrittlement after annealing. For 2CrMoV (WWER-440 reactor pressure vessel) steel with low contents of copper and phosphorus, the comparison of two embrittlement dependencies has been done: on irradiation temperature and post-irradiation annealing temperature. It is demonstrated that data for both the transition temperature shift after irradiation, ΔTk, and the residual transition temperature shift after post-irradiation annealing, ΔTres, fall within the same scatter band. A similarly close correlation is observed by comparison of yield strength increases after irradiation and after post-irradiation annealing.

  15. Thermal annealing as a method to predict results of high temperature irradiation embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Kryukov, A.; Debarberis, L. [European Commission, Joint Research Centre - Institute for Energy and Transport, PO Box 2, 1755 ZG Petten (Netherlands); Haehner, P., E-mail: peter.haehner@jrc.nl [European Commission, Joint Research Centre - Institute for Energy and Transport, PO Box 2, 1755 ZG Petten (Netherlands); Gillemot, F. [Hungarian Academy of Science Atomic Energy Research Institute, Erd. Olvasztar u. 22, H-2030 Budapest (Hungary); Oszvald, F. [Nuclear Power Plant ' Paks' , 7031 Paks (Hungary)

    2013-01-15

    In order to assess the validity of post-irradiation annealing as a method to predict results of high temperature irradiation a new analysis of experimental data has been performed revealing the combined influence of annealing temperature and impurities content on residual embrittlement after annealing. For 2CrMoV (WWER-440 reactor pressure vessel) steel with low contents of copper and phosphorus, the comparison of two embrittlement dependencies has been done: on irradiation temperature and post-irradiation annealing temperature. It is demonstrated that data for both the transition temperature shift after irradiation, {Delta}T{sub k}, and the residual transition temperature shift after post-irradiation annealing, {Delta}T{sub res}, fall within the same scatter band. A similarly close correlation is observed by comparison of yield strength increases after irradiation and after post-irradiation annealing.

  16. Effect of Solution Annealing Temperatures on the Crevice Corrosion Mode of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    El-Dasher, B S; Etien, R; Torres, S G

    2005-10-31

    The effect of solution annealing temperature on the observed corrosion attack mode in Alloy 22 welds was assessed. Three types of specimens were examined, including the as-welded state, solution annealed for 20 minutes at 1121 C, and solution annealed for 20 minutes at 1200 C. The microstructures of the specimens were first mapped using electron backscatter diffraction to determine the grain structure evolution due to solution annealing. The specimens were then subjected to electrochemical testing in a 6 molal NaCl + 0.9 molal KNO{sub 3} environment to initiate crevice corrosion. Examination of the specimen surfaces after corrosion testing showed that in the as-welded specimen, corrosion was present in both the weld dendrites as well as around the secondary phases. However, the specimen solution annealed at 1121 C showed corrosion only at secondary phases and the specimen annealed at 1200 C showed pitting corrosion only in a handful of grains.

  17. Strain relaxation near high-k/Si interface by post-deposition annealing

    International Nuclear Information System (INIS)

    We studied the effect of post-deposition annealing on a HfO2/Si interface of by extremely asymmetric X-ray diffraction. Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm3 grows at the interface between the HfO2 layer and the substrate during post-deposition annealing. The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO2 layer

  18. Considerable improvement in the stability of solution processed small molecule OLED by annealing

    International Nuclear Information System (INIS)

    We investigated the annealing effect on solution processed small organic molecule organic films, which were annealed with various conditions. It was found that the densities of the spin-coated (SC) films increased and the surface roughness decreased as the annealing temperature rose. We fabricated corresponding organic light emitting diodes (OLEDs) by spin coating on the same annealing conditions. The solution processed OLEDs show the considerable efficiency and stability, which were prior or equivalent to the vacuum-deposited (VD) counterparts. Our research shows that annealing process plays a key role in prolonging the lifetime of solution processed small molecule OLEDs, and the mechanism for the improvement of the device performance upon annealing was also discussed.

  19. Annealing studies of α-irradiated Bi-Sr-Ca-Cu-O superconductors

    International Nuclear Information System (INIS)

    Polycrystalline samples of Bi2Sr2CaCu2O8+x (Bi-2212) and Bi1.84Pb0.34Sr1.91Ca2.03Cu3.06O10+x (Bi-2223) superconductors irradiated with 40 MeV α-particles at various doses have been annealed in oxygen and air. Irradiated Bi-2212 samples have been annealed at 450 deg C and Bi-2223 samples have been annealed at 500 deg C as well as at high temperature (850 deg C). At lower dose of irradiation, Tc of Bi-2212 samples has decreased after annealing. In case of Bi-2223, there has been partial recovery by annealing at low temperature. But, annealing at high temperature has been detrimental. (author). 6 refs., 3 tabs., 3 figs

  20. A determination of the benefits of annealing irradiated pressure vessel weldments

    International Nuclear Information System (INIS)

    The long-term benefit of annealing an irradiated reactor pressure vessel steel may be described in terms of a benefit factor, B. The benefit factor compares the mechanical properties of an annealed and reirradiated specimen with an equivalent specimen having no intermediate anneal. The benefit factor was determined using a series of microhardness specimens prepared from nuclear pressure vessel surveillance program materials. These specimens were annealed and then reirradiated in a test reactor. There was an obvious long-term benefit in the specimens annealed at 4500C. The long-term benefit was less obvious at 4000C and no significant benefit was noted at 3500C. The benefit factor may also be used as the basis of a surveillance program for an annealed pressure vessel. A strategy for such a surveillance program is described. (author)

  1. Rapid thermal annealing and crystallization mechanisms study of silicon nanocrystal in silicon carbide matrix.

    Science.gov (United States)

    Wan, Zhenyu; Huang, Shujuan; Green, Martin A; Conibeer, Gavin

    2011-01-01

    In this paper, a positive effect of rapid thermal annealing (RTA) technique has been researched and compared with conventional furnace annealing for Si nanocrystalline in silicon carbide (SiC) matrix system. Amorphous Si-rich SiC layer has been deposited by co-sputtering in different Si concentrations (50 to approximately 80 v%). Si nanocrystals (Si-NC) containing different grain sizes have been fabricated within the SiC matrix under two different annealing conditions: furnace annealing and RTA both at 1,100°C. HRTEM image clearly reveals both Si and SiC-NC formed in the films. Much better "degree of crystallization" of Si-NC can be achieved in RTA than furnace annealing from the research of GIXRD and Raman analysis, especially in high-Si-concentration situation. Differences from the two annealing procedures and the crystallization mechanism have been discussed based on the experimental results. PMID:21711625

  2. Enhancement of Stability of Polymer Light-Emitting Diodes by Post Annealing

    Institute of Scientific and Technical Information of China (English)

    YAO Bing; XIE Zhi-Yuan; YANG Jun-Wei; CHENG Yan-Xiang; WANG Li-Xiang

    2007-01-01

    We investigate the effect of thermal annealing before and after cathode deposition on the stability of polymer light-emitting diodes (PLEDs) based on green fluorescent polyfluorene derivative. The annealed PLEDs exhibit improved charge transport and red-shift emission compared to the as-fabricated device. The stability of the PLEDs is largely enhanced by post-annealing before and after Ca deposition, which is attributed to the enhanced charge transport and the intimate contact between the cathode and the emissive layer.

  3. Recognition of hairpin DNA from coil DNA by electrospray mass spectrometry with annealing strategy

    Institute of Scientific and Technical Information of China (English)

    Bo Zheng; Yi Quan Liu; Gu Yuan

    2012-01-01

    This research presented an annealing strategy to identify hairpin DNA from coil DNA with the same base composition but different arrangements using electrospray mass spectrometry (ESI-MS).A series of single-stranded DNA were annealed with their complementary sequences,respectively.All the five pairs of hairpin DNA and coil DNA were unambiguously distinguished by ESIMS with annealing strategy.This research offers a potential method to probe the DNA structure by comparing with mass spectral characteristics.

  4. Low-temperature illumination and annealing of ultra-high quality quantum wells

    OpenAIRE

    Samani, Mohammad; Rossokhaty, Alexander V.; Sajadi, Ebrahim; Lüscher, Silvia; Folk, Joshua A.; Watson, John D.; Gardner, Geoffrey C.; Manfra, Michael J.

    2014-01-01

    The effects of low temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below 1 K, decreases the density of the 2DEG electrons by more than an order of magnitude and resets the sample to a repeatable initial state. Subsequent thermal annealing at a few Kelvin restores the original density and dramatically improves FQH characteristics. A reliable illumination and annealing recipe is developed...

  5. Heavy tails in the distribution of time-to-solution for classical and quantum annealing

    OpenAIRE

    Steiger, Damian S.; Rønnow, Troels F.; Troyer, Matthias

    2015-01-01

    For many optimization algorithms the time-to-solution depends not only on the problem size but also on the specific problem instance and may vary by many orders of magnitude. It is then necessary to investigate the full distribution and especially its tail. Here we analyze the distributions of annealing times for simulated annealing and simulated quantum annealing (by path integral quantum Monte Carlo) for random Ising spin glass instances. We find power-law distributions with very heavy tail...

  6. Annealing Induced Transmission Improvements and Photoluminescence Reduction of ARROW Optofluidic Chips for Improved Fluorescence Detection

    OpenAIRE

    Parks, Joshua W.

    2012-01-01

    Effects of thermal annealing on liquid- and solid-core antiresonant reflective optical waveguides (ARROW) are herein investigated. Transmission changes of 10 to 1000 fold increases are observed post annealing at either 300 or 700 °C. Furthermore, upon 700 °C annealing, the detectable photoluminescence of tantalum oxide cladding layers is reduced to half that of its original value. The suggestible cause for change in transmission is increased modal confinement within the ridge waveguid...

  7. Constrained multi-global optimization using a penalty stretched simulated annealing framework

    OpenAIRE

    Pereira, Ana I.; Edite M.G.P. Fernandes

    2009-01-01

    This paper presents a new simulated annealing algorithm to solve constrained multi-global optimization problems. To compute all global solutions in a sequential manner, we combine the function stretching technique with the adaptive simulated annealing variant. Constraint-handling is carried out through a nondifferentiable penalty function. To benchmark our penalty stretched simulated annealing algorithm we solve a set of well-known problems. Our preliminary numerical results show that the alg...

  8. Time series forecasting using a TSK fuzzy system tuned with simulated annealing

    OpenAIRE

    Almaraashi, Majid; John, Robert; Coupland, Simon; Hopgood, Adrian

    2010-01-01

    In this paper, a combination of a Takagi-Sugeno fuzzy system (TSK) and simulated annealing is used to predict well known time series by searching for the best configuration of the fuzzy system. Simulated annealing is used to optimise the parameters of the antecedent and the consequent parts of the fuzzy system rules. The results of the proposed method are encouraging indicating that simulated annealing and fuzzy logic are able to combine well in time series prediction.

  9. Influence of cold rolling and annealing on mechanical properties of steel QStE 420

    OpenAIRE

    I. Schindler; M. Janošec; E. Místecký; M. Růžička; L. Čížek a; L.A. Dobrzański; S. Rusz; P. Suchánek

    2006-01-01

    Purpose: was to investigate impact of cold reduction size and annealing on mechanical properties of HSLAsteel.Design/methodology/approach: Testing of strip steel QStE 420 was based on a combination of cold rolling,recrystallization annealing, mechanical testing and metallographic analyses.Findings: It was confirmed that by a suitable combination of size of previous cold deformation and parametersof the following annealing it is possible to influence considerably a complex of mechanical proper...

  10. X-ray diffraction investigation of self-annealing in nanocrystalline copper electrodeposits

    International Nuclear Information System (INIS)

    X-ray diffraction analysis and electrical resistivity measurements were conducted simultaneously for in-situ examination of self-annealing in copper electrodeposits. Considerable growth of the as-deposited nano-sized crystallites occurs with time and the crystallographic texture changes by multiple twinning during self-annealing. The kinetics of self-annealing depends on the layer thickness as well as on the orientation and/or the size of the as-deposited crystallites

  11. Connection between Annealed Free Energy and Belief Propagation on Random Factor Graph Ensembles

    OpenAIRE

    Mori, Ryuhei

    2011-01-01

    Recently, Vontobel showed the relationship between Bethe free energy and annealed free energy for protograph factor graph ensembles. In this paper, annealed free energy of any random regular, irregular and Poisson factor graph ensembles are connected to Bethe free energy. The annealed free energy is expressed as the solution of maximization problem whose stationary condition equations coincide with equations of belief propagation since the contribution to partition function of particular type...

  12. X-ray diffraction investigation of self-annealing in nanocrystalline copper electrodeposits

    Energy Technology Data Exchange (ETDEWEB)

    Pantleon, Karen [Department of Manufacturing Engineering and Management, Technical University of Denmark, Kemitorvet b. 204, DK - 2800 Kgs. Lyngby (Denmark)]. E-mail: pantleon@ipl.dtu.dk; Somers, Marcel A.J. [Department of Manufacturing Engineering and Management, Technical University of Denmark, Kemitorvet b. 204, DK - 2800 Kgs. Lyngby (Denmark)

    2006-08-15

    X-ray diffraction analysis and electrical resistivity measurements were conducted simultaneously for in-situ examination of self-annealing in copper electrodeposits. Considerable growth of the as-deposited nano-sized crystallites occurs with time and the crystallographic texture changes by multiple twinning during self-annealing. The kinetics of self-annealing depends on the layer thickness as well as on the orientation and/or the size of the as-deposited crystallites.

  13. A Study on Stainless Steel 316L Annealed Ultrasonic Consolidation and Linear Welding Density Estimation

    OpenAIRE

    Gonzalez, Raelvim

    2010-01-01

    Ultrasonic Consolidation of stainless steel structures is being investigated for potential applications. This study investigates the suitability of Stainless Steel 316L annealed (SS316L annealed) as a building material for Ultrasonic Consolidation (UC), including research on Linear Welding Density (LWD) estimation on micrographs of samples. Experiment results are presented that include the effect of UC process parameters on SS316L annealed UC, optimum levels of these parameters, and bond qual...

  14. Electrical conductivity of copper nanoparticle thin films annealed at low temperature

    OpenAIRE

    Yabuki, Akihiro; Arriffin, Norzafriza

    2010-01-01

    Copper nanoparticles with a mean diameter of 20 nm were used to prepare electrical conductive films at low temperature. After dispersal in an organic solvent, the copper nanoparticle pastes were coated onto a glass substrate, which was then annealed under various conditions to investigate the effects of various atmospheric conditions, such as air, nitrogen gas or hydrogen gas, as well as different annealing temperatures. Two-step annealing, which first involves oxidation in air followed by re...

  15. Properties of a Nb-V-Ti microalloyed steel influenced by cold rolling and annealing

    OpenAIRE

    M. Janošec; I. Schindler; J. Palát; L. Čížek; V. Vodárek; E. Místecký; Růžička, M. (Marek); L.A. Dobrzański; S. Rusz; P. Suchánek

    2007-01-01

    Purpose: was to investigate impact of cold forming and annealing on microstructural and mechanical propertiesof HSLA steel.Design/methodology/approach: Testing of Nb-V-Ti microalloyed strip steel was based on a combination ofcold rolling, recrystallization annealing, mechanical testing, metallography and TEM.Findings: It was confirmed that by a suitable combination of size of previous cold reduction size and parametersof the following annealing it is possible to influence considerably a compl...

  16. Chromium depletion from stainless steels during vacuum annealing

    International Nuclear Information System (INIS)

    The behaviour of chromium during selective evaporation by high temperature vacuum annealing has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that the rate of chromium loss from austenitic stainless steels 316 and 321 is controlled by chromium inter-diffusion rather than tracer diffusion in the alloy. Two important parameters in selective removal of chromium from alloy steels are the variation in the chromium surface concentration with time and the depletion profile in the alloy. The present work gives support for the model in which loss of chromium is dependent on its diffusivity in the alloy and on an interface transfer coefficient. The results showed that the surface concentration of chromium decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in accord with the previous derived model, apart from an anomalous near surface region. Here the higher resolution of a neutron activation technique indicated a region within approximately 2 microns of the surface where the chromium concentration decreased more steeply than expected. (author)

  17. Ion implant rapid thermal anneal international round robin

    Science.gov (United States)

    Yarling, C. B.; Andrew Keenan, W.

    1989-02-01

    The Greater Silicon Valley Implant Users' Group (GSVIUG) has conducted two round robin evaluations to determine the uniformity and repeatability available on commercial rapid thermal processing (RTP) equipment when processing implanted wafers. Twelve RTF vendors have participated, including AET Addax, A.G. Associates, Dainippon Screen, Eaton, Koyo Lindberg, Nanosil, Nichiden Machinery, Peak Systems, Process Products, Tamarack Scientific, Thermco/TEL, and Varian Associates. Sheet resistance contour maps were used to compare sheet resistance, uniformity and repeatability of each vendor. The first round robin was conducted using 100 mm wafers, implanted with high doses (1 × 10 15 and 1 × 10 6 ions/cm 2) of 100 keV boron and arsenic. The time and temperature ( t- T) of the anneal was left to the individual vendors to provide the best repeatability and uniformity for their equipment. The results indicate that excellent repeatability and uniformity are possible using RTP, but no single vendor was superior for all implant conditions. The second round robin was done using 150 mm wafers implanted with 5 × 10 15 ions/cm 2 arsenic at 80 keV. Each vendor was given four wafers to anneal at 1100 °C for 5, 10, 15 and 20 s. Results indicate that each vendor has a characteristic pattern, that much work needs to be done to standardize the t- T measurement, and that the uniformity on 150 mm wafers requires work by some vendors.

  18. STRUCTURAL ANALYSIS OF ANNEALED LEAD PHTHALOCYANINE THIN FILMS

    Directory of Open Access Journals (Sweden)

    P.Kalugasalam

    2010-07-01

    Full Text Available The thin films of Lead Phthalocyanine (PbPc on glass substrates were prepared by Vacuum deposition. The thicknesses of the films were 150 nm, 300nm and 450 nm on glass substrate. The thickness of the film was 150 nm on KCl substrate. The thickness of sample 450 nm annealed at 323 K and 373 K temperature. Diffraction is one of the most powerful methods of the study and structure of materials, which mayinvolve X-rays, electrons. The relative ease and convenience, large diffraction angle, representation of the average crystalline lattice throughout the film and simultaneous display of diffraction pattern from the film make the XRD method a successful analytical technique for the study of thin films. The sample has been analysed by X-ray diffraction (XRD to get structural analysis of the PbPc thin film. From the XRD patterns higher thickness of PbPc films show a triclinic grains (T seen along with monoclinic (M forms of PbPc. The sample is annealed at 323 K and 373 K temperatures; the film shows peaks that assigned to the triclinic phase.

  19. Precision and the approach to optimality in quantum annealing processors

    Science.gov (United States)

    Johnson, Mark W.

    The last few years have seen both a significant technological advance towards the practical application of, and a growing scientific interest in the underlying behaviour of quantum annealing (QA) algorithms. A series of commercially available QA processors, most recently the D-Wave 2XTM 1000 qubit processor, have provided a valuable platform for empirical study of QA at a non-trivial scale. From this it has become clear that misspecification of Hamiltonian parameters is an important performance consideration, both for the goal of studying the underlying physics of QA, as well as that of building a practical and useful QA processor. The empirical study of the physics of QA requires a way to look beyond Hamiltonian misspecification.Recently, a solver metric called 'time-to-target' was proposed as a way to compare quantum annealing processors to classical heuristic algorithms. This approach puts emphasis on analyzing a solver's short time approach to the ground state. In this presentation I will review the processor technology, based on superconducting flux qubits, and some of the known sources of error in Hamiltonian specification. I will then discuss recent advances in reducing Hamiltonian specification error, as well as review the time-to-target metric and empirical results analyzed in this way.

  20. Strain localization in annealed Cu50Zr50 metallic glass

    International Nuclear Information System (INIS)

    Highlights: → Analysis of the atomic structural change of the Cu50Zr50 by the heat treatment. → Confirmation of the change in the mechanical behavior obtained experimentally. → Verification of the validity of the normalized relaxation heat parameter. → Measure the strain localization using computational elastostatic compression. - Abstract: A molecular dynamics simulation technique was used to investigate the atomic structural changes in Cu50Zr50 metallic glass during isothermal annealing, with the aim of clarifying the mechanism responsible for the reduction of the plasticity experimentally observed during uniaxial loading of heat-treated Cu50Zr50. The atomic strain during shear deformation was calculated for the as-cast and annealed samples to evaluate the degree of strain localization, which affects the global plasticity of the alloys. The validity of the normalized relaxation heat parameter used to evaluate the degree of strain localization has been verified during elastostatic compression. The variation of the potential energy in the elastic regime, which was found to be correlated to the degree of strain localization, is proposed as parameter to evaluate by computational simulation the ability of an amorphous alloy to deform plastically.

  1. Job Shop Scheduling Using Modified Simulated Annealing Algorithm

    Directory of Open Access Journals (Sweden)

    PV Senthiil

    2014-09-01

    Full Text Available Timely and cost factor is increasingly important in today’s global competitive market. The key problem faced by today’s industries are feasible allocation of various jobs to available resources i.e., machines (Scheduling and optimal utilization of the available resources. Among the various problems in scheduling, the job shop scheduling is the most complicated and requires a large computational effort to solve it. A typical job shop scheduling problem has a set of jobs to be processed in a set of machines, with certain constraints and objective function to be achieved. The most commonly considered objectives are the minimization of make span, minimization of tardiness which leads to minimization of penalty cost, and to maximize machine utilization. Machine shop scheduling can be done using various techniques like standard dispatching rules, heuristic techniques like Simulated annealing, Tabu Search, Genetic algorithm, etc,.here a typical job shop shop scheduling problem is solved using simulated annealing(SA technique, a heuristic search algorithm. SA is generic neighbourhood search algorithm used to locate optimal solution very nearer to global optimal solution. A software based program is developed in VB platform for a typical job shop problem and test instances were performed over it. Experimental results obtained were further tuned by varying parameters and optimal results were obtained

  2. List-Based Simulated Annealing Algorithm for Traveling Salesman Problem.

    Science.gov (United States)

    Zhan, Shi-hua; Lin, Juan; Zhang, Ze-jun; Zhong, Yi-wen

    2016-01-01

    Simulated annealing (SA) algorithm is a popular intelligent optimization algorithm which has been successfully applied in many fields. Parameters' setting is a key factor for its performance, but it is also a tedious work. To simplify parameters setting, we present a list-based simulated annealing (LBSA) algorithm to solve traveling salesman problem (TSP). LBSA algorithm uses a novel list-based cooling schedule to control the decrease of temperature. Specifically, a list of temperatures is created first, and then the maximum temperature in list is used by Metropolis acceptance criterion to decide whether to accept a candidate solution. The temperature list is adapted iteratively according to the topology of the solution space of the problem. The effectiveness and the parameter sensitivity of the list-based cooling schedule are illustrated through benchmark TSP problems. The LBSA algorithm, whose performance is robust on a wide range of parameter values, shows competitive performance compared with some other state-of-the-art algorithms. PMID:27034650

  3. Enhanced regeneration of degraded polymer solar cells by thermal annealing

    International Nuclear Information System (INIS)

    The degradation and thermal regeneration of poly(3-hexylethiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and P3HT:indene-C60 bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells with a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles

  4. Effects of Annealing on Microstructure and Microstrength of Metallurgical Coke

    Science.gov (United States)

    Xing, Xing; Zhang, Guangqing; Rogers, Harold; Zulli, Paul; Ostrovski, Oleg

    2013-12-01

    Two metallurgical cokes were heat treated at 1673 K to 2273 K (1400 °C to 2000 °C) in a nitrogen atmosphere. The effect of heat treatment on the microstructure and microstrength of metallurgical cokes was characterized using X-ray diffraction, Raman spectroscopy, and ultra-microindentation. In the process of heat treatment, the microstructure of the metallurgical cokes transformed toward the graphite structure. Raman spectroscopy of reactive maceral-derived component (RMDC) and inert maceral-derived component (IMDC) indicated that the graphitisation degree of the RMDC was slightly lower than that of the IMDC in the original cokes; however graphitisation of the RMDC progressed faster than that of the IMDC during annealing, and became significantly higher after annealing at 2273 K (2000 °C). The microstrength of cokes was significantly degraded in the process of heat treatment. The microstrength of the RMDC was lower, and of its deterioration caused by heat treatment was more severe than IMDC. The degradation of the microstrength of cokes was attributed to their increased graphitisation degree during the heat treatment.

  5. Evaluation of trapping parameters of annealed natural quartz

    Science.gov (United States)

    Zhou, Rui; Wei, Ming-Jian; Song, Bo; Zhang, Yan; Zhao, Qiu-Yue; Pan, Bao-Lin; Li, Teng-Fei

    2016-05-01

    The thermoluminescence (TL) trapping parameters of annealed quartz have been investigated. The apparent TL peaks observed at temperatures of 133 °C, 211 °C, 266 °C and 405 °C, respectively, were named Peak I, Peak II, Peak III and Peak IV. The Tm - Tstop method is applied to investigate the number of peaks and their positions, and to obtain the trap distributions in the quartz. Peak shape (PS), Hoogenstraaten method (Various Heating Rates Method, VHR), and Computerized Glow Curve Deconvolution (CGCD) are used to evaluate the trapping parameters of the annealed quartz. The glow curve can be considered as a superposition of at least nine overlapping peaks. These peaks show up at 133 °C, 211 °C, 266 °C, 308 °C, 333 °C, 384 °C, 441 °C, 466 °C and 484 °C. The PS method can be only used in evaluating the parameters for Peaks I. The VHR method can be used in evaluating the trapping parameters for the first three peaks. CGCD method is complementary to obtaining parameters for the sub-peaks, and the thermal quenching correction with the Urbach's method is necessary. The Urbach's coefficient for the quartz is 30.03 kTm.

  6. Defect reduction in silicon nanocrystals by low-temperature annealing

    Energy Technology Data Exchange (ETDEWEB)

    Niesar, Sabrina; Erhard, Nadine; Stegner, Andre R.; Brandt, Martin S.; Stutzmann, Martin [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany); Pereira, Rui N. [University of Aveiro (Portugal); Wiggers, Hartmut [Institut fuer Verbrennung und Gasdynamik, Universitaet Duisburg-Essen, Duisburg (Germany)

    2010-07-01

    Due to the potential of low-cost solution processing, freestanding silicon nanocrystals (Si-ncs) are a promising base material for application e.g. in photovoltaics, thermoelectric and printable electronics. They can be synthesized in macroscopic amounts with diameters tunable between 4 and 50 nm by microwave-induced decomposition of silane in a low-pressure plasma reactor. In this work, we investigate different cost-efficient post-growth methods to reduce the number of silicon dangling bond defects (Si-dbs) which are a limiting factor for many electronic applications. Using electron paramagnetic resonance measurements, it is found that an etching step with hydrofluoric (HF) acid combined with a low-temperature vacuum annealing at 200 C leads to a reduction of the Si-dbs density by a factor of 10. Furthermore, conductivity measurements performed on thin Si-ncs films show that HF etching and annealing also improves the electronic properties. For highly doped Si-ncs, we observe a significant and persistent increase of the room-temperature conductivity. Moreover, current-voltage measurements on Si-ncs/organic semiconductor heterojunction solar cells are presented.

  7. Power change in amorphous silicon technology by low temperature annealing

    Directory of Open Access Journals (Sweden)

    Mittal Ankit

    2015-01-01

    Full Text Available Amorphous silicon (a-Si is one of the best established thin-film solar-cell technologies. Despite its long history of research, it still has many critical issues because of its defect rich material and its susceptibility to degrade under light also called as Staebler-Wronski effect (SWE. This leads to an increase in the defect density of a-Si, but as a metastable effect it can be completely healed at temperatures above 170 °C. Our study is focused on investigating the behavior of annealing of different a-Si modules under low temperature conditions below 80 °C indicated by successive change of module power. These conditions reflect the environmental temperature impact of the modules in the field, or integrated in buildings as well. The power changes were followed by STC power rating and investigation of module-power evolution under low irradiance conditions at 50 W/m2. Our samples were recovered close to their initial state of power, reaching as high as 99% from its degraded value. This shows the influence of low temperature annealing and light on metastable module behavior in a-Si thin-film modules.

  8. Microstructure evolution of hot-rolled ODS steel during annealing

    International Nuclear Information System (INIS)

    Oxide Dispersion strengthened (ODS) steels have a great potential for high burn-up and high temperature applications. General requirements for cladding material are high resistances to irradiation-induced embrittlement, void swelling, and creep, as well as a good compatibility with the molten sodium. Creep resistance at high temperature is closely related to thermal stability of microstructure, and is also affected by crystallographic texture that developed during the thermo-mechanical processes. In general, fine grain structure impairs creep resistance and strong texture leads to mechanical anisotropy. The present work investigates effects of oxide particles on thermal stability of microstructure and texture of ferritic ODS steel. For this purpose, Fe-15Cr base ferritic steel and its ODS counterpart were produced based on powder metallurgy and their microstructure were compared. The oxide particles in 15Cr ODS steel are stable at annealing temperatures up to 1200 .deg. C. However, further increase in annealing temperature results in dissolution and coarsening of oxides particles, which in turn leads to rapid growth of grains. Therefore, it is concluded that the ODS steel should be processed at temperature below 1200 .deg. C to avoid dissolution and coarsening of finely-dispersed oxide particles, and thereby to minimize loss of strength

  9. Simulated Annealing-Based Krill Herd Algorithm for Global Optimization

    Directory of Open Access Journals (Sweden)

    Gai-Ge Wang

    2013-01-01

    Full Text Available Recently, Gandomi and Alavi proposed a novel swarm intelligent method, called krill herd (KH, for global optimization. To enhance the performance of the KH method, in this paper, a new improved meta-heuristic simulated annealing-based krill herd (SKH method is proposed for optimization tasks. A new krill selecting (KS operator is used to refine krill behavior when updating krill’s position so as to enhance its reliability and robustness dealing with optimization problems. The introduced KS operator involves greedy strategy and accepting few not-so-good solutions with a low probability originally used in simulated annealing (SA. In addition, a kind of elitism scheme is used to save the best individuals in the population in the process of the krill updating. The merits of these improvements are verified by fourteen standard benchmarking functions and experimental results show that, in most cases, the performance of this improved meta-heuristic SKH method is superior to, or at least highly competitive with, the standard KH and other optimization methods.

  10. Isothermal and isochronal annealing experiments on irradiated commercial power VDMOSFETs

    International Nuclear Information System (INIS)

    The paper presents results of isothermal and isochronal annealing experiments on several types of gamma-ray irradiated commercial N- and P-channel power VDMOSFETs. Transistors were characterized for their threshold voltage shift and densities of radiation-induced oxide-trap charge and interface traps. The results show that the temperature enhances interface trap formation and oxide-trap charge decay rates, but also contributes to the passivation of interface traps. The study demonstrates that formation and passivation of interface traps are simultaneous processes. At certain conditions (lower temperature and/or positive bias) interface-trap formation dominates. Oppositely, at other conditions (higher temperature and/or negative bias) passivation is predominant. However at some conditions there is a complex interplay between formation and passivation of interface traps, resulting in interface traps increase followed by decrease at later annealing times. No model for interface trap post-irradiation behavior can explain this effect better than the recently proposed H-W model

  11. Fast assembly of ordered block copolymer nanostructures through microwave annealing.

    Science.gov (United States)

    Zhang, Xiaojiang; Harris, Kenneth D; Wu, Nathanael L Y; Murphy, Jeffrey N; Buriak, Jillian M

    2010-11-23

    Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy. PMID:20964379

  12. Simulated annealing technique to design minimum cost exchanger

    Directory of Open Access Journals (Sweden)

    Khalfe Nadeem M.

    2011-01-01

    Full Text Available Owing to the wide utilization of heat exchangers in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change the design and geometric parameters to satisfy a given heat duty and constraints. Although well proven, this kind of approach is time consuming and may not lead to cost effective design as no cost criteria are explicitly accounted for. The present study explores the use of nontraditional optimization technique: called simulated annealing (SA, for design optimization of shell and tube heat exchangers from economic point of view. The optimization procedure involves the selection of the major geometric parameters such as tube diameters, tube length, baffle spacing, number of tube passes, tube layout, type of head, baffle cut etc and minimization of total annual cost is considered as design target. The presented simulated annealing technique is simple in concept, few in parameters and easy for implementations. Furthermore, the SA algorithm explores the good quality solutions quickly, giving the designer more degrees of freedom in the final choice with respect to traditional methods. The methodology takes into account the geometric and operational constraints typically recommended by design codes. Three different case studies are presented to demonstrate the effectiveness and accuracy of proposed algorithm. The SA approach is able to reduce the total cost of heat exchanger as compare to cost obtained by previously reported GA approach.

  13. Mechanical annealing under low-amplitude cyclic loading in micropillars

    Science.gov (United States)

    Cui, Yi-nan; Liu, Zhan-li; Wang, Zhang-jie; Zhuang, Zhuo

    2016-04-01

    Mechanical annealing has been demonstrated to be an effective method for decreasing the overall dislocation density in submicron single crystal. However, simultaneously significant shape change always unexpectedly happens under extremely high monotonic loading to drive the pre-existing dislocations out of the free surfaces. In the present work, through in situ TEM experiments it is found that cyclic loading with low stress amplitude can drive most dislocations out of the submicron sample with virtually little change of the shape. The underlying dislocation mechanism is revealed by carrying out discrete dislocation dynamic (DDD) simulations. The simulation results indicate that the dislocation density decreases within cycles, while the accumulated plastic strain is small. By comparing the evolution of dislocation junction under monotonic, cyclic and relaxation deformation, the cumulative irreversible slip is found to be the key factor of promoting junction destruction and dislocation annihilation at free surface under low-amplitude cyclic loading condition. By introducing this mechanics into dislocation density evolution equations, the critical conditions for mechanical annealing under cyclic and monotonic loadings are discussed. Low-amplitude cyclic loading which strengthens the single crystal without seriously disturbing the structure has the potential applications in the manufacture of defect-free nano-devices.

  14. Radiation hardness of pre-annealed optical fibers

    International Nuclear Information System (INIS)

    In this paper, fused silica optical fiber is pre-annealed before irradiation after drawing process. After the heat-treatment, irradiation test is carried out at the cobalt-60 gamma-ray irradiation facility and fast neutron source. Pre-annealing effect and the temperature dependence of radiation induced optical transmission loss was investigated using the Co-60 gamma-ray and 14 MeV fast neutron source. The transmission losses in the visible wavelength range were much larger than in the infrared wavelength range, and the loss could be reduced in the whole wavelength range by the heat-treatment before irradiation. The reduction of transmission loss by the heat-treatment after drawing process before irradiation had the temperature dependence. It is found that an optimum temperature to minimize the transmission loss (radiation damage) exists, in other words, the radiation resistance can improve by the heat treatment of a specific temperature. The optimum temperature might be near 200 and 100degC under gamma-ray and fast neutron irradiation, respectively. (author)

  15. Surface Segregation of B During Box Annealing of ConCast Steels

    Science.gov (United States)

    Biber, H. E.; Hudson, R. M.

    1987-03-01

    In this study, significant surface concentrations of boron and nitrogen (presumably present as boron nitride) were observed in Auger electron spectrometry (AES) analysis of steels that were continuously cast with a mold flux containing boron oxide and commercially box annealed with dry H2-N2 atmospheres. A review of the thermochemistry of boron in steel suggested that the surface enrichment in boron and nitrogen occurs by a reaction during annealing in dry atmospheres. Laboratory annealing trials demonstrated the effectiveness of high dew point H2-N2 annealing atmospheres in suppressing that reaction. AES analysis indicates that the surface enrichment is not uniform and may be a function of surface grain orientation.

  16. Influence of annealing treatment on microstructure and properties of cold sprayed stainless steel coatings

    Institute of Scientific and Technical Information of China (English)

    Xianming MENG; Junbao ZHANG; Jie ZHAO; Wei HAN; Yongli LIANG

    2011-01-01

    304 stainless steel coatings had been deposited on carbon-steel substrate by cold spray technique, vacuum annealing treatment was applied to the coatings with different temperatures, and the influence of annealing treatment on the microstructure and electrochemical behavior of the coatings in 3.5% NaCl were analyzed. The results indicated that, the cold sprayed coating was constituted by the flattened particles, and the interfaces were clearly observed between the deposited particles. It was also found that annealing treatment led to the recovery and recrystallization of the elongated grains in the as-sprayed coatings with the increase of annealing temperature.When the annealing temperature achieved to 950 ℃, the interface of particles was disappeared and the coating's structure was made of new recrystallization anstenite grains. Annealing treatment increased the potential volts, and reduced the corrosion rate with the increase of annealing temperature. The electrical corrosion morphology indicated that, the corrosion was firstly at the distortion area and the crevice corrosion mechanism played an important part. Based on these results, processes active during annealing treatment are kinetically dependent and strongly influenced by the annealing treatment temperature.

  17. FEM analysis of large thermo-deflection of strips being processed in a continuous annealing furnace

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    No matter what the flatness of a strip is, flat or defective, at an annealing furnace entrance, the strip can not keep its original shape and a remarkable change of its shape can be seen at the annealing furnace exit. By inves tigating this phenomenon at the 2030 mm continuous annealing line which belonged to Baosteel, a finite element model of thermo-mechanical buckling deformation of strips in a continuous annealing furnace were established, and the mechanism of flatness changing and the contributing factors were researched by the finite element software ANSYS.

  18. Optical, Electrical and Raman Properties of Annealed Hydrogenated Mg/Co Bilayer Thin Films

    Directory of Open Access Journals (Sweden)

    M. Singh

    2011-01-01

    Full Text Available Bilayer Mg/Co thin films prepared using thermal evaporation method at pressure 10 – 5 torr at room temperature. The films were rapid thermal annealed (RTA using halogen lamp for different times to get a homogeneous structure of Mg/Co thin films. The hydrogen gas was introduced in hydrogen chamber, where samples were kept at different pressure of H2 for thirty minutes. The UV–VIS transmission spectra of annealed and annealed hydrogenated films have been carried out at room temperature in the wavelength range of 300-800 nm. The optical band gap was found to be increased due to hydrogenation and decrease with annealing time and also conductivity has been found to be decreased with hydrogen and increased with annealing time. Raman spectra show decreasing intensity of peaks with annealing and hydrogenation. Relative resistivity varies nonlinearly with time and decreases with annealing time. Surface morphology of annealed and annealed hydrogenated bilayer thin films has been confirmed by optical microscopy.

  19. Defect evolution and dopant activation in laser annealed Si and Ge

    DEFF Research Database (Denmark)

    Cristiano, F.; Shayesteh, M.; Duffy, R.;

    2016-01-01

    doped junctions. In this paper, we report some recent investigations focused on this annealing method, with particular emphasis on the investigation of the formation and evolution of implant/anneal induced defects and their impact on dopant activation. In the case of laser annealed Silicon, we show that...... very high activation rates. As for laser annealed Germanium, we studied in detail the amorphous to crystalline Ge phase transition as a function of the increasing LTA energy density and we found that using LTA, very high carrier concentrations (above 1020 cm-3) were achieved in As doped regions, which...

  20. Annealing of proton implanted tetragonal YBa 2Cu 3O 7- x

    Science.gov (United States)

    Katsuhiro, Yokota; Takeshi, Kura; Saichi, Katayama; Akiyoshi, Chayahara; Mamoru, Satho

    1991-07-01

    500 keV protons were implanted into sintered tetragonal YBa 2Cu 3O 7 - x (t-YBCO) with a dose of 1 × 10 17 cm -2. Implanted YBCO was annealed in oxygen at 300-800°C to induce a tetragonal-to-orthorhombic phase transformation. A superconducting transition of implanted YBCO annealed at 400°C for 240 min started at 98 K, higher than 91 K of unimplanted YBCO annealed at 400°C for 240 min. Annealing at 800°C changed again from superconducting orthorhombic YBCO to semiconducting tetragonal YBCO.

  1. Annealing to reduce scattering centers in Czochralski-grown beta-BaB2O4.

    Science.gov (United States)

    Kouta, H; Kuwano, Y

    1999-02-20

    When a visible laser beam passes through beta-BaB(2)O(4) (BBO), scattered light can be observed along the beam within the crystal. Scattering centers caused by structural defects in Czochralski-grown BBO can be reduced by 95% by annealing at 920 degrees C. In the flux-grown BBO, centers actually increase by the same annealing because the process causes microcracks and/or secondary inclusions. It is shown that annealed Czochralski-grown BBO is superior to flux-grown BBO (annealed or as-grown) in terms of optical loss. PMID:18305712

  2. Effects of Rapid Cycle Annealing Temperature on TbFe Magnetostrictive Films

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong-Chuan; ZHANG Jin-Ping; ZHANG Wan-Li; PENG Bin; ZHANG Wen-Xu; YANG Shi-Qing; ZHANG Huai-Wu

    2004-01-01

    @@ The effects of annealing temperature on TbFe films prepared by dc magnetron sputtering were discussed. X-ray diffraction patterns indicate that these polycrystalline films consisting mainly of α-Fe and TbFe2 lave phase with grain sizes less than 25 nm can be obtained by a rapid cycle annealing process. Grain sizes can be controlled by varying annealing temperatures. Film hysteresis loop studies show that annealing treatment can improve TbFe film in-plane soft magnetic performances.

  3. High-temperature annealing and surface photovoltage shifts on Si(111)7×7

    OpenAIRE

    Zhang, Hanmin; Sakamoto, K; Hansson, Göran; Uhrberg, Roger

    2008-01-01

    The relation between annealing temperature and surface photovoltage (SPV) shifts on the Si(111)7×7 surface of lightly n-doped substrates has been studied by core-level and valence-band photoelectron spectroscopies at 100 K. The SPV shift was found to depend strongly on the annealing temperature and the photon flux. Between 900 and 1150 °C the magnitude of the SPV shift shows a general decrease with annealing temperature. After a narrow plateau, the SPV shift becomes positive for annealings at...

  4. Influence of recrystallization annealing on the cube texture in high-purity aluminum foils

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.M.; Tang, J.G.; Du, Y.X.; Zhou, Z.P.; Chen, Z.Y.; Liu, C.M. [Dept. of Materials Science and Engineering, Central South Univ., HN (China)

    2001-07-01

    The cube texture in high-purity aluminum foils under different annealing conditions was investigated by means of orientation distribution function (ODF) and microscopy. It was shown that low recrystallization temperature was favorable to the nucleation of cube orientation and to the growth of the cube nuclei, and that stronger cube texture was obtained by multistage annealing than by single one. The strongest cube texture in high purity aluminum foils annealed in two-stage in the vacuum was obtained. It demonstrated that the recrystallization behavior was controlled by the existing state of Fe in aluminum. A model of multistage annealing was proposed for development of strong cube texture with temperature. (orig.)

  5. The effect of annealing and desulfurization on oxide spallation of turbine airfoil material

    International Nuclear Information System (INIS)

    In this paper the authors report a study that addresses the sulfur-induced spallation theory. Previous work has shown that a high temperature anneal in hydrogen desulfurizes nickel-base alloys and greatly improves their resistance to oxide spallation. The authors will show that such an anneal can be applied successfully to a Ni-base airfoil material. Both Auger segregation experiments and chemical analyses show that this anneal desulfurizes the material, at least in the absence of yttrium. However, the results suggest that factors other than desulfurization may be contributing to the improvement in spallation resistance produced by the anneal

  6. Annealing Polymer Nanocomposite Fibers and Films Via Photothermal Heating: Effects On Overall Crystallinity and Morphology

    Science.gov (United States)

    Viswanath, Vidya

    Metal nanoparticles embedded within polymeric systems can act as localized heat sources, facilitating in situ polymer processing. When irradiated with light resonant with the nanoparticle's surface plasmon resonance (SPR), a non-equilibrium electron distribution is generated which rapidly transfers energy into the surrounding medium, resulting in a temperature increase in the immediate region around the particle. This work compares the utility of such photothermal heating versus traditional heating in two different polymeric media i.e. gold nanospheres/poly (ethylene oxide) (AuNP:PEO) nanocomposite films and electrospun nanofibers. Subsequently, a brief study on the usage of gold nanorods (AuNR) to anneal polymeric nanofibers and films has also been presented. Effect of annealing by conventional and photothermal methods has been studied for AuNP:PEO films crystallized from solution and the melt, which have been annealed at average sample temperatures above the glass transition and below the melting point. For all temperatures, photothermally annealed samples reached maximum crystallinity and maximum spherulite size at shorter annealing times. Percentage crystallinity change under conventional annealing was analyzed using time-temperature superposition (TTS). Comparison of the TTS data with results from photothermal experiments enabled determination of an "effective dynamic temperature" achieved under photothermal heating which is significantly higher than the average sample temperature. Thus, the heterogeneous temperature distribution created when annealing with the plasmon-mediated photothermal effect represents a unique tool to achieve processing outcomes that are not accessible via traditional annealing. In addition, the effect of annealing AuNP:PEO electrospun nanofibrous composites via conventional and photothermal annealing has also been studied. From the studies, it was observed that not only is the maximum crystallinity achieved more quickly when the

  7. The effect of annealing on spectra and decay time of X-ray luminescence of zinc oxide powders

    International Nuclear Information System (INIS)

    The annealing effects on zinc oxide powders have been investigated. Annealing was performed at 800, 1050°C in vacuum and air for 2 h. After that, the powders were annealed in gas mixture consisted of 15% H2 and 85% Ar for 30 min at 800°C. After vacuum annealing the powders have green luminescence band located at 515 nm and decay time curve of the luminescence has three exponential decays with time constants: 10–50 ns, 100–200 ns, and 1100 ns. After air annealing powders have green luminescence band with peak at 525 nm and decay time curve of the luminescence has three exponential decays with time constants: 5 ns, 100–200 ns, and 4000–5000 ns. Annealing in hydrogenous ambience has no effect on peak position or intensity for powders previously annealed vacuum. In air annealed powders intensity of green luminescence decreases significantly after annealing in hydrogenous ambience

  8. Annealing induced recrystallization of radiation damaged titanite and allanite

    International Nuclear Information System (INIS)

    in the titanite structure. Hence, the planes containing Si-O-Ti-O bond rings are less susceptible to a self-accumulation of radiation-induced defects resulting in the development of amorphous regions as compared to the perpendicular plane containing Ti-O bond chains. Multistep annealing gradually suppresses the structural defects in the crystalline fraction of the titanite as the improvement of the SiO4-TiO6 connectivity within planes near perpendicular to the TiO6 chains reaches saturation near 900 K. Annealing-induced recrystallization of the radiation-induced amorphous nanoregions takes place in the temperature range between approximately 650 and 950 K, with a maximum near 750 K. To determine the influence of radiation damage on the behavior of the elastic material properties of titanite, nanoindentation measurements were performed on partially metamict titanite (sample E2312) and for comparison additionally on nearly undamaged crystalline titanite (Rauris sample) and titanite glass. Metamict titanite E2312 shows hardness (H) and elastic modulus (E) values close to those of titanite glass. Rauris titanite shows strong anisotropy and the H and E values are clearly larger than those of E2312. Thermally induced stepwise recrystallization of metamict titanite E2312 leads to a decrease in the hardness until approximately 950 K and afterwards to an increase at higher temperatures, while the elastic modulus increases continuously (H and E values measured always at room temperature). Changes of the hardness and elastic modulus are related to increasing long-range order and vanishing amorphous interface areas in the titanite structure. In further studies the structural recovery of the metamict epidot group mineral allanite (sample number R1) produced by thermal annealing was followed by powder X-ray diffraction, single-crystal synchrotron X-ray diffraction and infrared spectroscopy. Allanite contains in contrast to titanite structural OH groups. But no evidences for a

  9. Post-annealing effects on pulsed laser deposition-grown GaN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yu-Wen; Wu, Hao-Yu; Lin, Yu-Zhong; Lee, Cheng-Che; Lin, Ching-Fuh, E-mail: lincf@ntu.edu.tw

    2015-02-27

    In this work, the post-annealing effects on gallium nitride (GaN) thin films grown from pulsed laser deposition (PLD) are investigated. The as-deposited GaN thin films grown from PLD are annealed at different temperatures in nitrogen ambient. Significant changes of the GaN crystal properties are observed. Raman spectroscopy is used to observe the crystallinity, the change of residual stress, and the thermal decomposition of the annealed GaN thin films. X-ray diffraction is also applied to identify the crystal phase of GaN thin films, and the surface morphology of GaN thin films annealed at different temperatures is observed by scanning electron microscopy. Through the above analyses, the GaN thin films grown by PLD undergo three stages: phase transition, stress alteration, and thermal decomposition. At a low annealing temperature, the rock salt GaN in GaN films is transformed into wurtzite. The rock salt GaN diminishes with increasing annealing temperature. At a medium annealing temperature, the residual stress of the film changes significantly from compressive strain to tensile strain. As the annealing temperature further increases, the GaN undergoes thermal decomposition and the surface becomes granular. By investigating the annealing temperature effects and controlling the optimized annealing temperature of the GaN thin films, we are able to obtain highly crystalline and strain-free GaN thin films by PLD. - Highlights: • The GaN thin film is grown on sapphire by pulsed laser deposition. • The GaN film undergoes three stages with increasing annealing temperature. • In the first stage, the film transfers from rock salt to wurtzite phase. • In the second stage, the stress in film changes from compressive to tensile. • In the final stage, the film thermally decomposes and becomes granular.

  10. Post-annealing effects on pulsed laser deposition-grown GaN thin films

    International Nuclear Information System (INIS)

    In this work, the post-annealing effects on gallium nitride (GaN) thin films grown from pulsed laser deposition (PLD) are investigated. The as-deposited GaN thin films grown from PLD are annealed at different temperatures in nitrogen ambient. Significant changes of the GaN crystal properties are observed. Raman spectroscopy is used to observe the crystallinity, the change of residual stress, and the thermal decomposition of the annealed GaN thin films. X-ray diffraction is also applied to identify the crystal phase of GaN thin films, and the surface morphology of GaN thin films annealed at different temperatures is observed by scanning electron microscopy. Through the above analyses, the GaN thin films grown by PLD undergo three stages: phase transition, stress alteration, and thermal decomposition. At a low annealing temperature, the rock salt GaN in GaN films is transformed into wurtzite. The rock salt GaN diminishes with increasing annealing temperature. At a medium annealing temperature, the residual stress of the film changes significantly from compressive strain to tensile strain. As the annealing temperature further increases, the GaN undergoes thermal decomposition and the surface becomes granular. By investigating the annealing temperature effects and controlling the optimized annealing temperature of the GaN thin films, we are able to obtain highly crystalline and strain-free GaN thin films by PLD. - Highlights: • The GaN thin film is grown on sapphire by pulsed laser deposition. • The GaN film undergoes three stages with increasing annealing temperature. • In the first stage, the film transfers from rock salt to wurtzite phase. • In the second stage, the stress in film changes from compressive to tensile. • In the final stage, the film thermally decomposes and becomes granular

  11. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    International Nuclear Information System (INIS)

    Graphical abstract: The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. - Highlights: • Compactness and smoothness of the films were enhanced after sulfur annealing. • Micro-strain values of some films were improved after sulfur annealing. • Dislocation density values of some films were improved after sulfur annealing. • Band gap values of the films were improved after sulfur annealing. - Abstract: Cadmium sulfide (CdS) thin films were prepared on glass substrates by using chemical bath deposition (CBD) technique. The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. Compactness and smoothness of the films (especially for pH 10.5 and 11) enhanced after sulfur annealing. pH value of the precursor solution remarkably affected the roughness, uniformity and particle sizes of the films. Based on the analysis of X-ray diffraction (XRD) patterns of the films, micro-strain and dislocation density values of the sulfur-annealed films (pH 10.5 and 11) were found to be lower than those of air-annealed films. Air-annealed films (pH 10.5, 11 and 11.5) exhibited higher transmittance than sulfur-annealed films in the wavelength region of 550–800 nm. Optical band gap values of the films were found between 2.31 eV and 2.36 eV

  12. Effect of annealing on the structure of carbon onions and the annealed carbon coated Ni nanoparticles fabricated by chemical vapor deposition

    International Nuclear Information System (INIS)

    Structural evolutions of carbon onions and carbon coated nanocrystals of nickel during annealing process were investigated. X-ray diffraction, Raman and transmission electron microscope were used to investigate their structural variation. The results showed that annealing (700 deg. C) of the carbon onions resulted in the shrinkage of hollow core of carbon onions and reduction of the interlayer spacing between carbon onion shells. And the compressed onion structure took a perfect spheroidal shape. However, the structure of the annealed carbon coated Ni nanoparticles presented that the Ni nanoparticles (5-30 nm) escaped from carbon encapsulation and congregated to large Ni particles (30-180 nm), and the carbon coating was disintegrated to small disorder graphite pieces. When the Ni was removed from the carbon coated Ni nanoparticles and then was annealed at 700 deg. C for 4 h, it was found that these hollow carbon onions presented the similar structural evolution as the above carbon onions

  13. Comparative studies of laser annealing technique and furnace annealing by X-ray diffraction and Raman analysis of lithium manganese oxide thin films for lithium-ion batteries

    International Nuclear Information System (INIS)

    The structure and phase formations of radio frequency magnetron sputtered lithium manganese oxide thin films (Li1.1Mn1.9O4) under ambient air were studied. The influence of laser annealing and furnace annealing, respectively, on the bulk structure and surface phases was compared by using ex-situ X-ray diffraction and Raman analysis. Laser annealing technique formed a dominant (440)-reflection, furnace annealing led to both, (111)- and (440)-reflections within a cubic symmetry (S.G. Fd3m (227)). Additionally, in-situ Raman and in-situ X-ray diffraction were applied for online detection of phase transformation temperatures. In-situ X-ray diffraction measurements clearly identified the starting temperature for the (111)- and (440)-reflections around 525 °C and 400 °C, respectively. The 2θ Bragg peak positions of the characteristic (111)- and (440)-reflections were in good agreement with those obtained through conventional furnace annealing. Laser annealing of lithium manganese oxide films provided a quick and efficient technique and delivered a dominant (440)-reflection which showed the expected electrochemical behavior of the well-known two-step de-/intercalation process of lithium-ions into the cubic spinel structure within galvanostatic testing and cyclic voltammetry. - Highlights: ► Formation of cubic spinel-like phase of Li–Mn–O thin films by rapid laser annealing ► Laser annealing at 680 °C and 100 s was demonstrated as quick crystallization method. ► 400 °C was identified as characteristic onset temperature for (440)-reflex formation

  14. Optimal placement of excitations and sensors by simulated annealing

    Science.gov (United States)

    Salama, Moktar; Bruno, R.; Chen, G.-S.; Garba, J.

    1989-01-01

    The optimal placement of discrete actuators and sensors is posed as a combinatorial optimization problem. Two examples for truss structures were used for illustration; the first dealt with the optimal placement of passive dampers along existing truss members, and the second dealt with the optimal placement of a combination of a set of actuators and a set of sensors. Except for the simplest problems, an exact solution by enumeration involves a very large number of function evaluations, and is therefore computationally intractable. By contrast, the simulated annealing heuristic involves far fewer evaluations and is best suited for the class of problems considered. As an optimization tool, the effectiveness of the algorithm is enhanced by introducing a number of rules that incorporate knowledge about the physical behavior of the problem. Some of the suggested rules are necessarily problem dependent.

  15. Simulated annealing and joint manufacturing batch-sizing

    Directory of Open Access Journals (Sweden)

    Sarker Ruhul

    2003-01-01

    Full Text Available We address an important problem of a manufacturing system. The system procures raw materials from outside suppliers in a lot and processes them to produce finished goods. It proposes an ordering policy for raw materials to meet the requirements of a production facility. In return, this facility has to deliver finished products demanded by external buyers at fixed time intervals. First, a general cost model is developed considering both raw materials and finished products. Then this model is used to develop a simulated annealing approach to determining an optimal ordering policy for procurement of raw materials and also for the manufacturing batch size to minimize the total cost for meeting customer demands in time. The solutions obtained were compared with those of traditional approaches. Numerical examples are presented. .

  16. Simulated Annealing Algorithm and Its Application in Irregular Polygons Packing

    Institute of Scientific and Technical Information of China (English)

    段国林; 王彩红; 张健楠

    2003-01-01

    Two-dimensional irregular polygons packing problem is very difficult to be solved in traditional optimal way.Simulated annealing(SA)algorithm is a stochastic optimization technique that can be used to solve packing problems.The whole process of SA is introduced firstly in this paper. An extended neighborhood searching method in SA is mainly analyzed. A general module of SA algorithm is given and used to lay out the irregular polygons. The judgment of intersection and other constrains of irregular polygons are analyzed. Then an example that was used in the paper of Stefan Jakobs is listed.Results show that this SA algorithm shortens the computation time and improves the solution.

  17. Nuclide creation and annealing reactor waste in neutron fields

    International Nuclear Information System (INIS)

    We consider chemical elements in the Universe (their properties and transmutations) as a fuel powering an evolution of stars, galaxies, etc. The nuclear fusion reactions represent an energy source of stars and, in particular, the Sun fitting the life on the Earth. This brings a question on an origin and conditions for creation of life. We discuss some specific features of nuclear reaction chains at the hydrostatic burning of nuclides in stars and treaties for development of thermonuclear fusion reactors at the Earth based environment. The nova and supernova give promising astrophysical site candidates for synthesis of heavy atomic nuclei and renewing other nuclear components. Such an explosive nucleosynthesis yields the actinides containing basic fuel for nuclear fission reactors, among others. We briefly outline the e-, s-, and r-processes while accounting for ultra-strong stellar magnetization, and discuss some ideas for annealing the radioactive toxic nuclear waste

  18. Annealing in sulfur of CZTS nanoparticles deposited through doctor blading

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Crovetto, Andrea

    Solar cells made from nanoparticles of copper zinc tin sulfide (CZTS) from solution-processing are expected to be comparatively inexpensive, but their efficiency is still low compared with cells produced by vacuum processing. However, (1) the high carbon content in nanoparticle thin films is one...... results, however sulfurization has the advantage of being less toxic. In this work, nanocrystals of CZTS with a targeted Cu-poor/Zn-rich composition are synthesized through a hot-injection method with oleylamine as the solvent. The nanocrystal inks are deposited through doctor blading in octanethiol......). A photovoltaic device of the structure soda lime glass (SLG)/Mo/CZTSSe/CdS/ZnO:Al/Ag has been built, and our preliminary results show a power conversion efficiency of 1.41% for the nanoparticles annealed in selenium. This work has been supported by a grant from the Danish Council for Strategic Research...

  19. Memoryless cooperative graph search based on the simulated annealing algorithm

    Institute of Scientific and Technical Information of China (English)

    Hou Jian; Yan Gang-Feng; Fan Zhen

    2011-01-01

    We have studied the problem of reaching a globally optimal segment for a graph-like environment with a single or a group of autonomous mobile agents. Firstly, two efficient simulated-annealing-like algorithms are given for a single agent to solve the problem in a partially known environment and an unknown environment, respectively. It shows that under both proposed control strategies, the agent will eventually converge to a globally optimal segment with probability 1Secondly, we use multi-agent searching to simultaneously reduce the computation complexity and accelerate convergence based on the algorithms we have given for a single agent. By exploiting graph partition, a gossip consensus method based scheme is presented to update the key parameter-radius of the graph, ensuring that the agents spend much less time finding a globally optimal segment.

  20. Relaxation of the EM Algorithm via Quantum Annealing

    CERN Document Server

    Miyahara, Hideyuki

    2016-01-01

    The EM algorithm is a novel numerical method to obtain maximum likelihood estimates and is often used for practical calculations. However, many of maximum likelihood estimation problems are nonconvex, and it is known that the EM algorithm fails to give the optimal estimate by being trapped by local optima. In order to deal with this difficulty, we propose a deterministic quantum annealing EM algorithm by introducing the mathematical mechanism of quantum fluctuations into the conventional EM algorithm because quantum fluctuations induce the tunnel effect and are expected to relax the difficulty of nonconvex optimization problems in the maximum likelihood estimation problems. We show a theorem that guarantees its convergence and give numerical experiments to verify its efficiency.

  1. Maximum-Entropy Inference with a Programmable Annealer

    CERN Document Server

    Chancellor, Nicholas; Vinci, Walter; Aeppli, Gabriel; Warburton, Paul A

    2015-01-01

    Optimisation problems in science and engineering typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this approach maximises the likelihood that the solution found is correct. An alternative approach is to make use of prior statistical information about the noise in conjunction with Bayes's theorem. The maximum entropy solution to the problem then takes the form of a Boltzmann distribution over the ground and excited states of the cost function. Here we use a programmable Josephson junction array for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that maximum entropy decoding at finite temperature can in certain cases give competitive and even slightly better bit-error-rates than the maximum likelihood approach at zero temperature, confirming that useful information can be extracted from the excited states of the annealing...

  2. Low-temperature annealing -- A process to mitigate IASCC

    International Nuclear Information System (INIS)

    Low-temperature (400--500 C) annealing (LTA) treatments were carried out on Type 304SS, which had been irradiated to fast neutron fluences from 1.74 to 2.95 x 1021 n/cm2 (E > 1 MeV). The purpose of these treatments was to restore the stress-corrosion cracking (SCC) resistance of the unirradiated material. Certain treatments which were conducted at high enough temperatures and long enough times were successful in restoring part or all of the pre-irradiation SCC and hardness properties. Complete restoration of the SCC properties was observed before that of the pre-irradiation hardness. Stress-corrosion resistance was measured in constant extension rate tensile (CERT) and constant deflection tests. The effectiveness of a given LTA treatment was found to depend on the type of SCC test

  3. On the room-temperature annealing of cryogenically rolled copper

    International Nuclear Information System (INIS)

    Highlights: → Cryo-rolled copper is unstable during long-term storage at room-temperature. → Static recrystallization is nucleated via grain-boundary bulging and recovery. → Two competing recrystallization mechanisms result in a bimodal grain structure. → The specific nature of the recrystallization may induce abnormal grain growth. - Abstract: The electron-backscatter-diffraction (EBSD) technique was applied to investigate room-temperature annealing processes in cryogenically rolled copper during long-term (∼1.5 years) storage at ambient temperature. Static recrystallization appeared to be nucleated as result of both grain-boundary bulging and recovery. A bimodal recrystallized grain size distribution appeared to be a result of these two competing mechanisms. The ultra-fine grain copper produced via cryogenic deformation was deduced to be prone to abnormal grain growth after long static storage at room-temperature.

  4. Annealing of deep boron centers in silicon carbide

    CERN Document Server

    Ballandovich, V S

    2002-01-01

    Effect of thermal annealing on the high temperature luminescence efficiency (HTL) in 6H-SiC samples grown in different conditions and doped with boron impurity was investigated. Some of the crystals were irradiated by reactor neutrons or fast electrons. The HTL efficiency was shown to depend on the abundance of deep boron centers discovered by capacitive spectroscopy as D-centers. High temperature treatment of samples results in decomposition of D-centers which is identified as B sub S sub i -V sub C complexes. The deep boron centers are shown to be stable at temperature as low as 1500 deg C. Conservation of these centers in SiC crystals at higher temperatures (up to 2600 deg C) is caused by presence of clusters which are the sources of nonequilibrium carbon vacancies

  5. Enhanced response from field-annealed magnetoelastic strain sensor

    Science.gov (United States)

    Dalponte, Alessandro; Bastos, Eduardo S.; Missell, Frank P.

    2016-08-01

    Magnetoelastic materials permit the development of remote-query strain sensors for use in situations of difficult access. In this work, we examined materials for a remote-query strain sensor based on the ΔE effect. An applied stress modifies the magnetic field produced by a transducer glued to the sample and thereby changes the resonant frequency of a vibrating amorphous ribbon. We considered several amorphous alloys for both the vibrating ribbon and the transducer. To eliminate the casting stress and improve the anisotropy, ribbons were annealed in a transverse magnetic field. This resulted in a dramatic improvement in the sensor performance when sensors were biased above the anisotropy field. For example, a Metglas 2826MB3 ribbon with resonant frequency of 62 kHz showed frequency shifts of up to 5 kHz for a deformation of 0.03%. These results are in good agreement with models for the ΔE effect.

  6. Solving the dynamic berth allocation problem by simulated annealing

    Science.gov (United States)

    Lin, Shih-Wei; Ting, Ching-Jung

    2014-03-01

    Berth allocation, the first operation when vessels arrive at a port, is one of the major container port optimization problems. From both the port operator's and the ocean carriers' perspective, minimization of the time a ship spends at berth is a key goal of port operations. This article focuses on two versions of the dynamic berth allocation problem (DBAP): discrete and continuous cases. The first case assigns ships to a given set of berth positions; the second one permits them to be moored anywhere along the berth. Simulated annealing (SA) approaches are proposed to solve the DBAP. The proposed SAs are tested with numerical instances for different sizes from the literature. Experimental results show that the proposed SA can obtain the optimal solutions in all instances of discrete cases and update 27 best known solutions in the continuous case.

  7. Restoration of polarimetric SAR images using simulated annealing

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning

    2001-01-01

    Filtering synthetic aperture radar (SAR) images ideally results in better estimates of the parameters characterizing the distributed targets in the images while preserving the structures of the nondistributed targets. However, these objectives are normally conflicting, often leading to a filtering...... approach favoring one of the objectives. An algorithm for estimating the radar cross-section (RCS) for intensity SAR images has previously been proposed in the literature based on Markov random fields and the stochastic optimization method simulated annealing. A new version of the algorithm is presented...... applicable to multilook polarimetric SAR images, resulting in an estimate of the mean covariance matrix rather than the RCS. Small windows are applied in the filtering, and due to the iterative nature of the approach, reasonable estimates of the polarimetric quantities characterizing the distributed targets...

  8. Simulated Annealing Clustering for Optimum GPS Satellite Selection

    Directory of Open Access Journals (Sweden)

    M. Ranjbar

    2012-05-01

    Full Text Available This paper utilizes a clustering approach based on Simulated Annealing (SA method to select optimum satellite subsets from the visible satellites. Geometric Dilution of Precision (GDOP is used as criteria of optimality. The lower the values of the GDOP number, the better the geometric strength, and vice versa. Not needing to calculate the inverse matrix, which is time-consuming process, is a dramatically important advantage of using this method, so a great reduction in computational cost is achieved. SA is a powerful technique to obtain a close approximation to the global optimum for a given problem. The evaluation of the performance of the proposed method is done by validation measures. The external validation measures, entropy and purity, are used to measure the extent to which cluster labels affirm with the externally given class labels. The overall purity and entropy is 0.9015 and 0.3993, respectively which is an excellent result.

  9. Implantation and annealing effects in molecular organic films

    CERN Document Server

    Pakhomov, G L; Shashkin, V I; Tura, J M; Ribo, J M; Ottaviano, L

    2002-01-01

    Ion implantation and annealing effects on the surface of phthalocyanine thin films have been studied by means of atomic force microscopy and electron spectroscopy for chemical analysis. Both the topology and the chemical composition of the surface are affected by irradiation. The influence of the irradiation dose is shown. The chemical degradation of the layer results mainly in the decrease of atomic concentration of nitrogen and chlorine, and in the increase of atomic concentration of oxygen. At highest dose, carbonization becomes important. Furthermore, N 1s, C 1s and Cl 2p core levels testify that the formation of new chemical species occurs in implanted pthalocyanine films. All these processes are modified by subsequent heat treatment in different ways, depending on the applied implantation fluence.

  10. Low temperature annealing of cold-drawn pearlitic steel wire

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Bech, Jakob Ilsted; Hansen, Niels

    2015-01-01

    , the thermal behaviour is of interest. This has been studied by annealing the wires for 1h at temperatures from ambient temperature to 300 ℃ (573 K). It is expected that a raising temperature may lead to structural changes and a reduction in strength. The change in strength is however not expected to be large....... For this reason we have applied a very precise technique to measure the tensile properties of the wires from a strain of 10-4 to the maximum strain of about 1-2%. The structural changes have also been followed to estimate and relate strength changes to changes in structural parameters and morphology.......Cold-drawn pearlitic steel wires are nanostructured and the flow stress at room temperature can reach values above 6 GPa. A typical characteristic of the nanostructured metals, is the low ductility and thermal stability. In order to optimize both the processing and application of the wires...

  11. Effect of annealing on mechanical properties of ledeburitic cast steel

    Directory of Open Access Journals (Sweden)

    E. Rożniata

    2007-01-01

    Full Text Available Purpose: The paper presents evaluation of influence of grain normalization (refinement as a result of repeatedaustenitizing, and the inclination to precipitate the hypereutectoid cementite in Widmannstätten structure inG200CrMoNi4-6-3 cast steel. Four temperatures of heat refining have been applied.Design/methodology/approach: Basic research of G200CrMoNi4-6-3 cast steel included metallographicanalysis, and hardness and impact strength tests. The heat treatment has been planned on the basis of CCTdiagram prepared for that alloy cast steel.Findings: The test material has been G200CrMoNi4-6-3 hypereutectoid cast steel. The evaluation has beencarried out for four annealing temperatures, i.e. 850°C, 900°C, 950°C and 1050°C. At all annealing temperaturesin the structure of cast steel the precipitation of hypereutectoid cementite along grain boundaries of formeraustenite took place. At the temperature of 850°C one may observe the coagulated hypereutectoid cementiteprecipitates inside of primary grains of austenite. Whereas beginning from the temperature of 900°C thecementite in G200CrMoNi4-6-3 cast steel forms distinct „subgrains” inside of primary grains of austenite.Research limitations/implications: Research financed by the Ministry of Scientific Research and InformationTechnology, grant No. 3 T08B 057 29.Practical implications: G200CrMoNi4-6-3 cast steel of ledeburite class is used mainly for rolls production.Any data related to the structure and mechanical properties of that cast steel are precious for the manufacturersand users of the mill rolls.Originality/value: The new heat treatment of G200CrMoNi4-6-3 cast steel

  12. Effect of Thermal Annealing on Tribological and Corrosion Properties of DLC Coatings

    Science.gov (United States)

    Wang, Linlin; Nie, X.; Hu, Xin

    2013-10-01

    In this study, the mechanical, tribological, and corrosion properties of annealed diamond-like carbon (DLC) coatings on M2 steel with various annealing temperatures were investigated. The results indicated that DLC coating on M2 steel annealed at 500 °C had the worst performance. Both corrosion polarization resistance and wear resistance against ceramic alumina counterface of DLC coatings decreased with increasing annealing temperature, which can be due to the decline of the coating hardness after the thermal treatment. When sliding against aluminum counterface material, the DLC annealed at 600 °C had the lowest coefficient of friction (cof) and wear resistance due to its high graphitic structure and low hardness. Compared with the original coating, cofs increased for coatings treated at below 300 °C; however, further increasing the annealing temperature led to the decrease of the cofs. Little material attachment occurred between DLC coatings (original and annealed) and counterface materials (both alumina and aluminum balls) except for the DLC annealed at 600 °C, in which coating material transferred to the surface of counterface ball.

  13. Magnetism of CoFe2O4 thin films annealed under the magnetic field

    International Nuclear Information System (INIS)

    Polycrystalline CoFe2O4 thin films were deposited on Si (100) substrates by chemical solution deposition with and without magnetic annealing. Magnetic field directions were applied parallel and perpendicular to the film surface during the magnetic annealing process. The variations of strain, microstructure and magnetic anisotropy of the films caused by the magnetic annealing are investigated. The results show that the film densification is promoted and grain morphology is changed by the magnetic annealing, which can be attributed to the promoting effect of magnetization force on the grain growing and grain boundary diffusing. Magnetic measurements indicate the enhancement of anisotropy and saturation magnetizations of the polycrystalline CoFe2O4 after magnetic annealing. Furthermore, the rotation of easy axis along the field direction, the increased occupation of Co2+ ions at B sites and the additional strain induced by the magnetic field are considered as the main reasons of the increased magnetic anisotropy. - Highlights: • CFO films were annealed in magnetic field with parallel and vertical directions. • The film densification and grain size were changed by the applied magnetic field. • A higher saturation magnetization is obtained under magnetic annealing. • The enhanced magnetic anisotropy is observed after magnetic annealing

  14. The influence of strain on annealing behaviour of heavily rolled aluminium AA1050

    DEFF Research Database (Denmark)

    Mishin, Oleg; Juul Jensen, Dorte; Hansen, Niels

    2012-01-01

    Deformation structures and annealing behaviour have been analysed in the centre layer of two AA1050 samples cold-rolled to von Mises strains of 3.6 and 6.4. During annealing at 270-300°C structural coarsening and discontinuous recrystallization occurred in both samples. In the coarsened...

  15. A Knowledge-Based Simulated Annealing Algorithm to Multiple Satellites Mission Planning Problems

    OpenAIRE

    Da-Wei Jin; Li-Ning Xing

    2013-01-01

    The multiple satellites mission planning is a complex combination optimization problem. A knowledge-based simulated annealing algorithm is proposed to the multiple satellites mission planning problems. The experimental results suggest that the proposed algorithm is effective to the given problem. The knowledge-based simulated annealing method will provide a useful reference for the improvement of existing optimization approaches.

  16. UN ALGORITMO DI SIMULATED ANNEALING PER LA SOLUZIONE DI UN PROBLEMA DI SCHEDULING

    OpenAIRE

    Crescenzio Gallo

    2004-01-01

    An algorithm of "Simulated Annealing" for solving scheduling problems is presented. The issues related to scheduling are discussed, together with the Simulated Annealing approximation method and its main parameters (freezing, temperature, cooling, number of neighbourhoods to explore), the choices made in defining them for the generation of a good algorithm that efficiently resolves the scheduling problem.

  17. The HARP domain dictates the annealing helicase activity of HARP/SMARCAL1

    OpenAIRE

    Ghosal, Gargi; Yuan, Jingsong; Chen, Junjie

    2011-01-01

    HARP/SMARCAL1 has a unique annealing helicase activity that is important for the enzyme's function in stabilizing stalled replications forks and facilitating DNA repair. The authors demonstrate here that the conserved tandem HARP domain, and not the SNF2 domain, dictates the annealing helicase activity.

  18. Effect of annealing on properties of Mg doped Zn-ferrite nanoparticles

    Institute of Scientific and Technical Information of China (English)

    K. Nadeemn; S. Rahman; M. Mumtaz

    2015-01-01

    A comparison of structural and magnetic properties of as-prepared and annealed (900 1C) Mg doped Zn ferrite nanoparticles (Zn1 ? xMgxFe2O4, with x ¼ 0, 0.1, 0.2, 0.3, 0.4 and 0.5) is presented. X-ray diffraction (XRD) studies confirmed the cubic spinel structure for both the as-prepared and annealed nanoparticles. The average crystallite size and lattice parameter were increased by annealing. Scanning electron microscopy (SEM) images also showed that the average particle size increased after annealing. Fourier transform infrared spectroscopy (FTIR) also confirmed the spinel structure for both series of nanoparticles. For both annealed and as-prepared nanoparticles, the O–Mtet.–O vibrational band shifts towards higher wave numbers with increased Mg concentration due to cationic rearrangement on the lattice sites. Magnetization studies revealed an anomalous decreasing magnetization for the annealed nanoparticles which is also ascribed to cationic rearrangement on the lattice sites after annealing. The measurement of coercivity showed a decreasing trend by annealing due to the increased nanoparticle size and better crystallinity.&2015 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license.

  19. Annealing effect on current perpendicular to plane systems modeled by giant magnetoresistance simulation

    NARCIS (Netherlands)

    Jonkers, PAE

    2001-01-01

    A simulation single-electron model is presented to describe the effect of annealing current perpendicular to plane-giant magnetoresistance (CPP-GMR) systems. Progressive annealing is represented by a progressively increasing number of impurities occurring at the interfaces of adjacent layers constit

  20. Weak convergence rates for stochastic approximation with application to multiple targets and simulated annealing

    OpenAIRE

    Pelletier, Mariane

    1998-01-01

    We study convergence rates of $\\mathbb{R}$-valued algorithms, especially in the case of multiple targets and simulated annealing. We precise, for example, the convergence rate of simulated annealing algorithms, whose weak convergence to a distribution concentrated on the potential's minima had been established by Gelfand and Mitter or by Hwang and Sheu.

  1. Annealing of UV-Induced Birefringence in Hydrogen Loaded Germanosilicate Fibres

    DEFF Research Database (Denmark)

    Canning, John; Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær;

    2005-01-01

    UV-reduced birefringence in germanosilicate optical fibres loaded with hydrogen is annealed out at low temperatures (125o C). Annealing for induced birefringence in gratings written by either s or p polarised UV light are identical. The results are incosistent with previous models for the origin of...

  2. Generalized simulated annealing algorithms using Tsallis statistics : Application to the discrete-time optimal growth problem

    OpenAIRE

    稻垣, 陽介; イナガキ, ヨウスケ; Yousuke, Inagaki

    2007-01-01

    The efficiency of Monte Carlo simulated annealing algorithm based on the generalized statistics of Tsallis (GSA) is compared with conventional simulated annealing (CSA) based on Boltzmann-Gibbs statistics. Application to the discrete-time optimal growth problem demonstrates that the replacement of CSA by GSA has the potential to speed up optimizations with no loss of accuracy in finding optimal policy function.

  3. Enhancement of exchange coupling and hard magnetic properties in nanocomposites by magnetic annealing

    International Nuclear Information System (INIS)

    An enhancement of the exchange coupling and hard magnetic properties of melt-spun Nd2Fe14B/α-Fe-type nanocomposites was achieved by optimization of their nanostructured morphology via magnetic annealing. Compared with the Nd2.4Pr5.6Dy1Fe84Mo1B6 sample annealed without a magnetic field, the magnetic annealing results in a noticeable improvement in the coercivity i H c, the remanence 4πMr, and energy product (BH)max. (BH)max at 50 K was enhanced by 43.7% after magnetic annealing in a field of 19 T. The kink in the demagnetization curve disappeared and, additionally, a much better squareness of the demagnetization curves was observed in the magnetically annealed samples. The intergrain exchange coupling was evaluated by Henkel plots. Evidence for stronger intergrain exchange coupling was found in the magnetically annealed sample, which is due to nanostructure refinement promoted by the magnetic annealing. The nanostructure refinement was confirmed by X-ray diffraction, transmission electron microscope, low-temperature demagnetization curves and a modified Brown's equation analysis. The improvement of hard magnetic properties of the magnetically annealed sample results mainly from the magnetic-field-induced exchange-coupling enhancement

  4. Surface Impedance of Copper MOB Depending on the Annealing Temperature and Deformation Degree

    International Nuclear Information System (INIS)

    Results of researches of influence of annealing temperature and deformation degree on mechanical features of copper MOB are presented. It is shown that minimal surface resistance is observed in copper samples that were subject to pre-deformation and were annealed in the range of temperatures 873...923 K

  5. 78 FR 31577 - Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan

    Science.gov (United States)

    2013-05-24

    ... Commission, Washington, DC, and by publishing the notice in the Federal Register of April 2, 2013 (78 FR... COMMISSION Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan Determination On the basis... injured by reason of imports from Japan of diffusion-annealed, nickel-plated flat-rolled steel...

  6. Studies of deep-level defects in flash lamp annealing of ion-implanted silicon

    International Nuclear Information System (INIS)

    The spatial uniformity and in-depth profile of phosphorus-ion-implanted silicon annealed by flash lamps were studied with Hall effect, spreading resistance and minority-carrier lifetime measurements. Deep levels in flash-lamp-annealed n+p diodes were examined using deep-level transient spectroscopy (DLTS) and reverse current measurements. A uniformly annealed area, about 40x40 mm2, was obtained, which coincided with the uniformly light-irradiated area of the flash lamp annealing system. In n+p diodes, two hole traps H1(Esub(v)+0.39 eV) and H2(Esub(v)+0.46 eV) were observed at 26 J cm-2, and two hole traps H1(Esub(v)+0.39 eV) and H3(Esub(v)+0.47 eV) were observed at 20 J cm-2. The spatial reverse current distributions within the wafer were similar to those of H2 defects. To remove these residual defects in diodes, effects of the additional furnace annealing and the multiple-shot irradiations were also investigated. H1 defects were annealed out with 7000C additional furnace heating for 30 min. H1 and H2 defects of 26 J cm-2 flash-lamp-annealed samples were annealed out by two-shot flash lamp irradiations. (author)

  7. Electrical behavior of amide functionalized graphene oxide and graphene oxide films annealed at different temperatures

    International Nuclear Information System (INIS)

    Films of graphene oxide (GO) and amide functionalized graphene oxides (AGOs) were deposited on SiO2/Si(100) by spin coating and were thermally annealed at different temperatures. Sheet resistance of GO and AGOs films was measured using four probe resistivity method. GO an insulator at room temperature, exhibits decrease in sheet resistance with increase in annealing temperature. However, AGOs' low sheet resistance (250.43 Ω) at room temperature further decreases to 39.26 Ω after annealing at 800 °C. It was observed that the sheet resistance of GO was more than AGOs up to 700 °C, but effect was reversed after annealing at higher temperature. At higher annealing temperatures the oxygen functionality reduces in GO and sheet resistance decreases. Sheet resistance was found to be annealing time dependent. Longer duration of annealing at a particular temperature results in decrease of sheet resistance. - Highlights: • Amide functionalized graphene oxides (AGOs) were synthesized at room temperature (RT). • AGO films have low sheet resistance at RT as compared to graphene oxide (GO). • Fast decrease in the sheet resistance of GO with annealing as compared to AGOs • AGOs were found to be highly dispersible in polar solvents

  8. Physical model of evolution of oxygen subsystem of PLZT-ceramics at neutron irradiation and annealing

    CERN Document Server

    Kulikov, D V; Trushin, Y V; Veber, K V; Khumer, K; Bitner, R; Shternberg, A R

    2001-01-01

    The physical model of evolution of the oxygen subsystem defects of the ferroelectric PLZT-ceramics by the neutron irradiation and isochrone annealing is proposed. The model accounts for the effect the lanthanum content on the material properties. The changes in the oxygen vacancies concentration, calculated by the proposed model, agree well with the polarization experimental behavior by the irradiated material annealing

  9. A Simulated Annealing Algorithm for Training Empirical Potential Functions of Protein Folding

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-hong; LI Wei

    2005-01-01

    In this paper are reported the local minimum problem by means of current greedy algorithm for training the empirical potential function of protein folding on 8623 non-native structures of 31 globular proteins and a solution of the problem based upon the simulated annealing algorithm. This simulated annealing algorithm is indispensable for developing and testing highly refined empirical potential functions.

  10. Sensitivity enhancement using annealed polymer optical-fibre-based sensors for pressure sensing applications

    Science.gov (United States)

    Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

    2016-05-01

    Thermal annealing can be used to induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors and it was originally used for multiplexing purposes. Recently, researchers showed that annealing can also provide additional benefits, such as strain and humidity sensitivity enhancement and augmented temperature operational range. The annealing process can change both the optical and mechanical properties of the fibre. In this paper, the annealing effects on the stress and force sensitivities of PMMA fibre Bragg grating sensors are investigated. The incentive for that investigation was an unexpected behaviour observed in an array of sensors which were used for liquid level monitoring. One sensor exhibited much lower pressure sensitivity and that was the only one that was not annealed. To further investigate the phenomenon, additional sensors were photo-inscribed and characterised with regard their stress and force sensitivities. Then, the fibres were annealed by placing them in hot water, controlling with that way the humidity factor. After annealing, stress and force sensitivities were measured again. The results show that the annealing can improve the stress and force sensitivity of the devices. This can provide better performing sensors for use in stress, force and pressure sensing applications.

  11. Selective aspect ratio of CNTs based on annealing temperature by TCVD method

    Science.gov (United States)

    Yousefi, Amin Termeh; Mahmood, Mohamad Rusop; Ikeda, Shoichiro

    2016-07-01

    Various aspect ratios of CNTs reported based on alteration of annealing temperature using thermal-chemical vapor deposition (TCVD) method. Also the growth dependent and independent parameters of the carbon nanotube (CNTs) array were studied as a function of synthesis method. The FESEM images indicate that the nanotubes are approximately perpendicular to the surface of the silicon substrate and form carbon nanotubes in different aspect ratios according to the applied annealing temperature. Furthermore, due to the optimized results it can be observed that, the mechanism of the CNTs growth is still present in the annealing step as well as deposition process and the most CNTs with crystalline aspect, produced in the annealing temperature, which was optimized at 700 - 900 ˚C. This result demonstrates that the growth rate, mass production, diameter, density, and crystallinity of CNT can be controlled by the annealing temperature.

  12. Atomistic aspects of carrier concentration variation in post-annealed indium tin oxide films

    International Nuclear Information System (INIS)

    Post-annealing environment-dependent optical and electrical properties of indium tin oxide films grown on glass were examined. X-ray diffraction measurements revealed that all of the films exhibited poly-crystallinity after annealing at 400 °C for 10 min O2, in-air and N2. The optical property measurements yielded  >80% transmittances for all the films except for the as-grown and O2-annealed films, even though there were no significant optical band-gap energy differences. In the Hall measurements, all of the films exhibited n-type characteristics. However, the film annealed under the N2 environment showed the best electrical properties (highest carrier concentration and conductivity). The physical origin of electrical property variations due to annealing environment differences was explained by examining the core-level x-ray photoelectron spectra. (paper)

  13. Annealing effects on residual stress of HfO2/SiO2 multilayers

    Institute of Scientific and Technical Information of China (English)

    Yanming Shen; Zhaoxia Han; Jianda Shao; Shuying Shao; Hongbo He

    2008-01-01

    HfO2/SiO2 multilayer films were deposited on BK7 glass substrates by electron beam evaporation method.The effects of annealing at the temperature between 200 and 400℃ on residual stresses have been studied.It is found that the residual stress of as-deposited HfO2/SiO2 multilayers is compressive.It becomes tensile after annealing at 200℃,and then the value of tensile stress increases as annealing temperature increases.And cracks appear in the film because tensile stress is too large when the sample is annealed at 400℃.At the same time,the crystallite size increases and interplanar distance decreases with the increase of annealing temperature.The variation of residual stresses is corresponding with the evolution of structures.

  14. Annealing results on low-energy proton-irradiated GaAs solar cells

    Science.gov (United States)

    Kachare, R.; Anspaugh, B. E.; O'Meara, L.

    1988-01-01

    AlGaAs/GaAs solar cells with an approximately 0.5-micron-thick Al(0.85)Ga(0.15)As window layer were irradiated using normal and isotropic incident protons having energies between 50 and 500 keV with fluence up to 1 x 10 to the 12th protons/sq cm. The irradiated cells were annealed at temperatures between 150 and 300 C in nitrogen ambient. The annealing results reveal that significant recovery in spectral response at longer wavelengths occurred. However, the short-wavelength spectral response showed negligible annealing, irrespective of the irradiation energy and annealing conditions. This indicates that the damage produced near the AlGaAs/GaAs interface and the space-charge region anneals differently than damage produced in the bulk. This is explained by using a model in which the as-grown dislocations interact with irradiation-induced point defects to produce thermally stable defects.

  15. Texture of hot rolled and annealed binary Ti-Mn alloys

    International Nuclear Information System (INIS)

    This work describes the development of texture during hot rolling and annealing of two binary Ti-Mn alloys. The alloys Ti-0.4Mn (α-type) and Ti-1.8Mn (near α-type) have been unidirectionally rolled up to 70% reduction at 750 C, and air-cooled. The samples taken from these hot rolled plates were subjected to isothermal annealing at 700 C for different lengths of time. After hot rolling, Ti-0.4Mn shows nearly a c-type texture, and Ti-1.8Mn an R-type texture. Annealing of the Ti-0.4Mn alloy generates a T-type texture, whilst annealing of the Ti-1.8Mn alloy leads to a continuous change in the hot rolling R-type texture. These results are compared with hot rolling and annealing textures of titanium and its alloys. (orig.)

  16. Picosecond and nanosecond laser annealing and simulation of amorphous silicon thin films for solar cell applications

    Science.gov (United States)

    Theodorakos, I.; Zergioti, I.; Vamvakas, V.; Tsoukalas, D.; Raptis, Y. S.

    2014-01-01

    In this work, a picosecond diode pumped solid state laser and a nanosecond Nd:YAG laser have been used for the annealing and the partial nano-crystallization of an amorphous silicon layer. These experiments were conducted as an alternative/complementary to plasma-enhanced chemical vapor deposition method for fabrication of micromorph tandem solar cell. The laser experimental work was combined with simulations of the annealing process, in terms of temperature distribution evolution, in order to predetermine the optimum annealing conditions. The annealed material was studied, as a function of several annealing parameters (wavelength, pulse duration, fluence), as far as it concerns its structural properties, by X-ray diffraction, SEM, and micro-Raman techniques.

  17. Picosecond and nanosecond laser annealing and simulation of amorphous silicon thin films for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Theodorakos, I.; Zergioti, I.; Tsoukalas, D.; Raptis, Y. S., E-mail: yraptis@central.ntua.gr [Physics Department, National Technical University of Athens, Heroon Polytechniou 9, 15780 Zographou, Athens (Greece); Vamvakas, V. [Heliosphera SA, Industrial Area of Tripolis, 8th Building Block, 5th Road, GR-221 00 Tripolis (Greece)

    2014-01-28

    In this work, a picosecond diode pumped solid state laser and a nanosecond Nd:YAG laser have been used for the annealing and the partial nano-crystallization of an amorphous silicon layer. These experiments were conducted as an alternative/complementary to plasma-enhanced chemical vapor deposition method for fabrication of micromorph tandem solar cell. The laser experimental work was combined with simulations of the annealing process, in terms of temperature distribution evolution, in order to predetermine the optimum annealing conditions. The annealed material was studied, as a function of several annealing parameters (wavelength, pulse duration, fluence), as far as it concerns its structural properties, by X-ray diffraction, SEM, and micro-Raman techniques.

  18. Single crystalline graphene synthesized by thermal annealing of humic acid over copper foils

    Science.gov (United States)

    Beall, Gary W.; Duraia, El-Shazly M.; Yu, Q.; Liu, Z.

    2014-02-01

    Production of graphene by thermal annealing on copper foil substrates has been studied with different sources of carbon. The three carbon sources include humic acid derived from leonardite, graphenol, and activated charcoal. Hexagonal single crystalline graphene has been synthesized over the copper foil substrates by thermal annealing of humic acid, derived from leonardite, in argon and hydrogen atmosphere (Ar/H2=20). The annealing temperature was varied between 1050 °C and 1100 °C at atmospheric pressure. Samples have been investigated using scanning electron microscope (SEM) and Raman spectroscopy. At lower temperatures the thermal annealing of the three carbon sources used in this study produces pristine graphene nanosheets which cover almost the whole substrate. However when the annealing temperature has been increased up to 1100 °C, hexagonal single crystalline graphene have been observed only in the case of the humic acid. Raman analysis showed the existence of 2D band around 2690 cm-1.

  19. Manipulation of magnetic properties of glass-coated microwires by annealing

    International Nuclear Information System (INIS)

    We demonstrated that magnetic properties (hysteresis loops, domain wall propagation and giant magnetoimpedance effect) of Fe and Co-rich amorphous microwires can be tailored by stress and conventional annealing. Observed dependences discussed considering stress relaxation, back stresses and change of the magnetostriction after samples annealing. These considerations have been proved by experimental observation of the change of the magnetostriction coefficient sign induced by annealing. - Highlights: • Manipulation of hysteresis loop of amorphous Co–Fe- rich microwires by annealing. • Coexistence of Giant magnetoimpedance effect and fast domain wall propagation in the same sample. • Evidence of annealing dependence of the magnetostriction coefficient. • Effect of stress induced anisotropy on magnetic properties and GMI effect

  20. Influence of Thermal Annealing on Structural and Electrical Properties of Nickel Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    A. Mallikarjuna Reddy

    2011-01-01

    Full Text Available Nickel oxide (NiO is a potential p-type transparent conducting oxide material with suitable electrical properties. Nickel oxide thin films were deposited by dc reactive magnetron sputtering technique on unheated glass substrates, and subsequently annealed at 773 K in two different annealing processes. X-ray diffractometer studies revealed that the films exhibited (200 preferred orientation. Scanning electron microscopy and energy dispersive spectroscopy were used to study the effect of annealing temperature on surface morphology and composition of the films. The uniform grains were distributed throughout the substrate after annealed at 773 K. Electrical properties were studied by Hall effect measurements. The low electrical resistivity of 36.9 Ω cm was observed after annealing.