WorldWideScience

Sample records for annealing

  1. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1982-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices in which the device is rapidly heated to a temperature between 450 and 900 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. (author)

  2. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1981-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices is described in which the device is rapidly heated to a temperature between 450 and 600 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. The process may be enhanced by the application of optical radiation from a Xenon lamp. (author)

  3. Cascade annealing: an overview

    International Nuclear Information System (INIS)

    Doran, D.G.; Schiffgens, J.O.

    1976-04-01

    Concepts and an overview of radiation displacement damage modeling and annealing kinetics are presented. Short-term annealing methodology is described and results of annealing simulations performed on damage cascades generated using the Marlowe and Cascade programs are included. Observations concerning the inconsistencies and inadequacies of current methods are presented along with simulation of high energy cascades and simulation of longer-term annealing

  4. 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-root relati......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...

  5. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys. SVETLANA NESTOROVIC. Technical Faculty Bor, University of Belgrade, Bor, Yugoslavia. MS received 11 February 2004; revised 29 October 2004. Abstract. This paper reports results of investigation carried out on sintered ...

  6. DOE's annealing prototype demonstration projects

    International Nuclear Information System (INIS)

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

    1997-01-01

    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

  7. 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...

  8. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. 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 fol-.

  9. Management of the Bohunice RPVs annealing procedures

    International Nuclear Information System (INIS)

    Repka, M.

    1994-01-01

    The program of annealing regeneration procedure of RPVs units 1 and 2 of NPP V-1 (EBO) realization in the year 1993, is the topic of this paper. In the paper the following steps are described in detail: the preparation works, the annealing procedure realization schedule and safety management: starting with zero conditions, assembling of annealing apparatus, annealing procedure, cooling down and disassembling procedure of annealing apparatus. At the end the programs of annealing of both RPVs including the dosimetry measurements are discussed and evaluated. (author). 3 figs

  10. Pulsed Laser Annealing of Carbon

    Science.gov (United States)

    Abrahamson, Joseph P.

    This dissertation investigates laser heating of carbon materials. The carbon industry has been annealing carbon via traditional furnace heating since at least 1800, when Sir Humphry Davy produced an electric arc with carbon electrodes made from carbonized wood. Much knowledge has been accumulated about carbon since then and carbon materials have become instrumental both scientifically and technologically. However, to this day the kinetics of annealing are not known due to the slow heating and cooling rates of furnaces. Additionally, consensus has yet to be reached on the cause of nongraphitizability. Annealing trajectories with respect to time at temperature are observed from a commercial carbon black (R250), model graphitizable carbon (anthracene coke) and a model nongraphitizable carbon (sucrose char) via rapid laser heating. Materials were heated with 1064 nm and 10.6 im laser radiation from a Q-switched Nd:YAG laser and a continuous wave CO2 laser, respectively. A pulse generator was used reduce the CO2 laser pulse width and provide high temporal control. Time-temperature-histories with nanosecond temporal resolution and temperature reproducibility within tens of degrees Celsius were determined by spectrally resolving the laser induced incandescence signal and applying multiwavelength pyrometry. The Nd:YAG laser fluences include: 25, 50, 100, 200, 300, and 550 mJ/cm2. The maximum observed temperature ranged from 2,400 °C to the C2 sublimation temperature of 4,180 °C. The CO2 laser was used to collect a series of isothermal (1,200 and 2,600 °C) heat treatments versus time (100 milliseconds to 30 seconds). Laser heated samples are compared to furnace annealing at 1,200 and 2,600 °C for 1 hour. The material transformation trajectory of Nd:YAG laser heated carbon is different than traditional furnace heating. The traditional furnace annealing pathway is followed for CO2 laser heating as based upon equivalent end structures. The nanostructure of sucrose char

  11. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    Unknown

    blended with sugarcane bagasse which showed good me- chanical properties when investigated by SEM, thermal gravimetric analysis (TGA), DSC and tensile testing (Chiel- lini et al 2001). An increase in the engineering yield stress was observed, with a decline in tensile impact strength. With DSC on annealing, a small ...

  12. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    The present paper reports the preparation of full IPNs of gelatin and polyacrylonitrile. Various compositions of gluteraldehyde crosslinked gelatin and N,N′-methylene-bis-acrylamide crosslinked PAN were characterized by SEM and DSC techniques. The IPNs were also thermally pretreated by the annealing process.

  13. Simulated annealing model of acupuncture

    Science.gov (United States)

    Shang, Charles; Szu, Harold

    2015-05-01

    The growth control singularity model suggests that acupuncture points (acupoints) originate from organizers in embryogenesis. Organizers are singular points in growth control. Acupuncture can cause perturbation of a system with effects similar to simulated annealing. In clinical trial, the goal of a treatment is to relieve certain disorder which corresponds to reaching certain local optimum in simulated annealing. The self-organizing effect of the system is limited and related to the person's general health and age. Perturbation at acupoints can lead a stronger local excitation (analogous to higher annealing temperature) compared to perturbation at non-singular points (placebo control points). Such difference diminishes as the number of perturbed points increases due to the wider distribution of the limited self-organizing activity. This model explains the following facts from systematic reviews of acupuncture trials: 1. Properly chosen single acupoint treatment for certain disorder can lead to highly repeatable efficacy above placebo 2. When multiple acupoints are used, the result can be highly repeatable if the patients are relatively healthy and young but are usually mixed if the patients are old, frail and have multiple disorders at the same time as the number of local optima or comorbidities increases. 3. As number of acupoints used increases, the efficacy difference between sham and real acupuncture often diminishes. It predicted that the efficacy of acupuncture is negatively correlated to the disease chronicity, severity and patient's age. This is the first biological - physical model of acupuncture which can predict and guide clinical acupuncture research.

  14. Quantum annealing for combinatorial clustering

    Science.gov (United States)

    Kumar, Vaibhaw; Bass, Gideon; Tomlin, Casey; Dulny, Joseph

    2018-02-01

    Clustering is a powerful machine learning technique that groups "similar" data points based on their characteristics. Many clustering algorithms work by approximating the minimization of an objective function, namely the sum of within-the-cluster distances between points. The straightforward approach involves examining all the possible assignments of points to each of the clusters. This approach guarantees the solution will be a global minimum; however, the number of possible assignments scales quickly with the number of data points and becomes computationally intractable even for very small datasets. In order to circumvent this issue, cost function minima are found using popular local search-based heuristic approaches such as k-means and hierarchical clustering. Due to their greedy nature, such techniques do not guarantee that a global minimum will be found and can lead to sub-optimal clustering assignments. Other classes of global search-based techniques, such as simulated annealing, tabu search, and genetic algorithms, may offer better quality results but can be too time-consuming to implement. In this work, we describe how quantum annealing can be used to carry out clustering. We map the clustering objective to a quadratic binary optimization problem and discuss two clustering algorithms which are then implemented on commercially available quantum annealing hardware, as well as on a purely classical solver "qbsolv." The first algorithm assigns N data points to K clusters, and the second one can be used to perform binary clustering in a hierarchical manner. We present our results in the form of benchmarks against well-known k-means clustering and discuss the advantages and disadvantages of the proposed techniques.

  15. 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

  16. Simulated annealing with constant thermodynamic speed

    International Nuclear Information System (INIS)

    Salamon, P.; Ruppeiner, G.; Liao, L.; Pedersen, J.

    1987-01-01

    Arguments are presented to the effect that the optimal annealing schedule for simulated annealing proceeds with constant thermodynamic speed, i.e., with dT/dt = -(v T)/(ε-√C), where T is the temperature, ε- is the relaxation time, C ist the heat capacity, t is the time, and v is the thermodynamic speed. Experimental results consistent with this conjecture are presented from simulated annealing on graph partitioning problems. (orig.)

  17. 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.

  18. Semantic search via concept annealing

    Science.gov (United States)

    Dunkelberger, Kirk A.

    2007-04-01

    Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. We define concept annealing as a lexical, syntactic, and semantic expansion capability (the removal of defects and the internal stresses that cause term- and phrase-based search failure) coupled with a directed contraction capability (semantically-related terms, queries, and concepts nucleate and grow to replace those originally deformed by internal stresses). These two capabilities are tied together in a control loop mediated by the information retrieval precision and recall metrics coupled with intuition provided by the operator. The specific representations developed have been targeted at facilitating highly efficient and effective semantic indexing and searching. This new generation of Find capability enables additional processing (i.e. all-source tracking, relationship extraction, and total system resource management) at rates, precisions, and accuracies previously considered infeasible. In a recent experiment, an order magnitude reduction in time to actionable intelligence and nearly three orderss magnitude reduction in false alarm rate was achieved.

  19. GPU accelerated population annealing algorithm

    Science.gov (United States)

    Barash, Lev Yu.; Weigel, Martin; Borovský, Michal; Janke, Wolfhard; Shchur, Lev N.

    2017-11-01

    Population annealing is a promising recent approach for Monte Carlo simulations in statistical physics, in particular for the simulation of systems with complex free-energy landscapes. It is a hybrid method, combining importance sampling through Markov chains with elements of sequential Monte Carlo in the form of population control. While it appears to provide algorithmic capabilities for the simulation of such systems that are roughly comparable to those of more established approaches such as parallel tempering, it is intrinsically much more suitable for massively parallel computing. Here, we tap into this structural advantage and present a highly optimized implementation of the population annealing algorithm on GPUs that promises speed-ups of several orders of magnitude as compared to a serial implementation on CPUs. While the sample code is for simulations of the 2D ferromagnetic Ising model, it should be easily adapted for simulations of other spin models, including disordered systems. Our code includes implementations of some advanced algorithmic features that have only recently been suggested, namely the automatic adaptation of temperature steps and a multi-histogram analysis of the data at different temperatures. Program Files doi:http://dx.doi.org/10.17632/sgzt4b7b3m.1 Licensing provisions: Creative Commons Attribution license (CC BY 4.0) Programming language: C, CUDA External routines/libraries: NVIDIA CUDA Toolkit 6.5 or newer Nature of problem: The program calculates the internal energy, specific heat, several magnetization moments, entropy and free energy of the 2D Ising model on square lattices of edge length L with periodic boundary conditions as a function of inverse temperature β. Solution method: The code uses population annealing, a hybrid method combining Markov chain updates with population control. The code is implemented for NVIDIA GPUs using the CUDA language and employs advanced techniques such as multi-spin coding, adaptive temperature

  20. Understanding the microwave annealing of silicon

    Directory of Open Access Journals (Sweden)

    Chaochao Fu

    2017-03-01

    Full Text Available Though microwave annealing appears to be very appealing due to its unique features, lacking an in-depth understanding and accurate model hinder its application in semiconductor processing. In this paper, the physics-based model and accurate calculation for the microwave annealing of silicon are presented. Both thermal effects, including ohmic conduction loss and dielectric polarization loss, and non-thermal effects are thoroughly analyzed. We designed unique experiments to verify the mechanism and extract relevant parameters. We also explicitly illustrate the dynamic interaction processes of the microwave annealing of silicon. This work provides an in-depth understanding that can expedite the application of microwave annealing in semiconductor processing and open the door to implementing microwave annealing for future research and applications.

  1. 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.

  2. 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.

  3. Enthalpy relaxation and annealing effect in polystyrene.

    Science.gov (United States)

    Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

    2013-07-01

    The effects of thermal history on the enthalpy relaxation in polystyrene are studied by differential scanning calorimetry. The temperature dependence of the specific heat in the liquid and the glassy states, that of relaxation time, and the exponent of the Kohlrausch-Williams-Watts function are determined by measurements of the thermal response against sinusoidal temperature variation. A phenomenological model equation previously proposed to interpret the memory effect in the frozen state is applied to the enthalpy relaxation and the evolution of entropy under a given thermal history is calculated. The annealing below the glass transition temperature produces two effects on enthalpy relaxation: the decay of excess entropy with annealing time in the early stage of annealing and the increase in relaxation time due to physical aging in the later stage. The crossover of these effects is reflected in the variation of temperature of the maximum specific heat observed in the heating process after annealing and cooling.

  4. Annealing behavior of high permeability amorphous alloys

    International Nuclear Information System (INIS)

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co 71 4 Fe 4 6 Si 9 6 B 14 4 were investigated. Annealing this alloy below 400 0 C results in magnetic hardening; annealing above 400 0 C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation

  5. Global warming: Temperature estimation in annealers

    Directory of Open Access Journals (Sweden)

    Jack Raymond

    2016-11-01

    Full Text Available Sampling from a Boltzmann distribution is NP-hard and so requires heuristic approaches. Quantum annealing is one promising candidate. The failure of annealing dynamics to equilibrate on practical time scales is a well understood limitation, but does not always prevent a heuristically useful distribution from being generated. In this paper we evaluate several methods for determining a useful operational temperature range for annealers. We show that, even where distributions deviate from the Boltzmann distribution due to ergodicity breaking, these estimates can be useful. We introduce the concepts of local and global temperatures that are captured by different estimation methods. We argue that for practical application it often makes sense to analyze annealers that are subject to post-processing in order to isolate the macroscopic distribution deviations that are a practical barrier to their application.

  6. 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....

  7. Irradiation embrittlement and optimisation of annealing

    International Nuclear Information System (INIS)

    1993-01-01

    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

  8. Boosting quantum annealer performance via sample persistence

    Science.gov (United States)

    Karimi, Hamed; Rosenberg, Gili

    2017-07-01

    We propose a novel method for reducing the number of variables in quadratic unconstrained binary optimization problems, using a quantum annealer (or any sampler) to fix the value of a large portion of the variables to values that have a high probability of being optimal. The resulting problems are usually much easier for the quantum annealer to solve, due to their being smaller and consisting of disconnected components. This approach significantly increases the success rate and number of observations of the best known energy value in samples obtained from the quantum annealer, when compared with calling the quantum annealer without using it, even when using fewer annealing cycles. Use of the method results in a considerable improvement in success metrics even for problems with high-precision couplers and biases, which are more challenging for the quantum annealer to solve. The results are further enhanced by applying the method iteratively and combining it with classical pre-processing. We present results for both Chimera graph-structured problems and embedded problems from a real-world application.

  9. Nanocrystalline magnetic materials obtained by flash annealing

    Directory of Open Access Journals (Sweden)

    Murakami R.K.

    1999-01-01

    Full Text Available The aim of the present work was to produce enhanced-remanence nanocrystalline magnetic material by crystallizing amorphous or partially amorphous Pr4.5Fe77B18.5 alloys by the flash annealing process, also known as the dc-Joule heating process, and to determine the optimal conditions for obtaining good magnetic coupling between the magnetic phases present in this material. Ribbons of Pr4.5Fe77B18.5 were produced by melt spinning and then annealed for 10-30 s at temperatures 500 - 640 °C by passing current through the sample to develop the enhanced-remanence nanocrystalline magnetic material. These materials were studied by X-ray diffraction, differential thermal analysis and magnetic measurements. Coercivity increases of up to 15% were systematically observed in relation to furnace-annealed material. Two different samples were carefully examined: (i a sample annealed at 600 °C which showed the highest coercive field Hc and remanence ratio Mr/Ms and (ii a sample annealed at 520 °C which showed phase separation in the second quadrant demagnetization curve. Our results are in agreement with other studies which show that flash annealing improves the magnetic properties of some amorphous ferromagnetic ribbons.

  10. Energy Saving in Industrial Annealing Furnaces

    Directory of Open Access Journals (Sweden)

    Fatma ÇANKA KILIÇ

    2018-03-01

    Full Text Available In this study, an energy efficiency studies have been carried out in a natural gas-fired rolling mill annealing furnace of an industrial establishment. In this context, exhaust gas from the furnace has been examined in terms of waste heat potential. In the examinations that have been made in detail; waste heat potential was found as 3.630,31 kW. Technical and feasibility studies have been carried out to realize electricity production through an Organic Rankine Cycle (ORC system for evaluating the waste heat potential of the annealing furnace. It has been calculated that 1.626.378,88 kWh/year of electricity can be generated by using the exhaust gas waste heat of the annealing furnace through an ORC system to produce electric energy with a net efficiency of 16%. The financial value of this energy was determined as 436.032,18 TL/year and the simple repayment period of the investment was 8,12 years. Since the annealing period of the annealing furnace is 2800 hours/year, the investment has not been found to be feasible in terms of the feasibility studies. However, the investment suitability can be assured when the annealing furnace is operating at full capacity for 8,000 hours or more annually.

  11. 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.

  12. Deterministic quantum annealing expectation-maximization algorithm

    Science.gov (United States)

    Miyahara, Hideyuki; Tsumura, Koji; Sughiyama, Yuki

    2017-11-01

    Maximum likelihood estimation (MLE) is one of the most important methods in machine learning, and the expectation-maximization (EM) algorithm is often used to obtain maximum likelihood estimates. However, EM heavily depends on initial configurations and fails to find the global optimum. On the other hand, in the field of physics, quantum annealing (QA) was proposed as a novel optimization approach. Motivated by QA, we propose a quantum annealing extension of EM, which we call the deterministic quantum annealing expectation-maximization (DQAEM) algorithm. We also discuss its advantage in terms of the path integral formulation. Furthermore, by employing numerical simulations, we illustrate how DQAEM works in MLE and show that DQAEM moderate the problem of local optima in EM.

  13. Traffic Flow Optimization Using a Quantum Annealer

    Directory of Open Access Journals (Sweden)

    Florian Neukart

    2017-12-01

    Full Text Available Quantum annealing algorithms belong to the class of metaheuristic tools, applicable for solving binary optimization problems. Hardware implementations of quantum annealing, such as the quantum processing units (QPUs produced by D-Wave Systems, have been subject to multiple analyses in research, with the aim of characterizing the technology’s usefulness for optimization and sampling tasks. In this paper, we present a real-world application that uses quantum technologies. Specifically, we show how to map certain parts of a real-world traffic flow optimization problem to be suitable for quantum annealing. We show that time-critical optimization tasks, such as continuous redistribution of position data for cars in dense road networks, are suitable candidates for quantum computing. Due to the limited size and connectivity of current-generation D-Wave QPUs, we use a hybrid quantum and classical approach to solve the traffic flow problem.

  14. Thermal annealing of tilted fiber Bragg gratings

    Science.gov (United States)

    González-Vila, Á.; Rodríguez-Cobo, L.; Mégret, P.; Caucheteur, C.; López-Higuera, J. M.

    2016-05-01

    We report a practical study of the thermal decay of cladding mode resonances in tilted fiber Bragg gratings, establishing an analogy with the "power law" evolution previously observed on uniform gratings. We examine how this process contributes to a great thermal stability, even improving it by means of a second cycle slightly increasing the annealing temperature. In addition, we show an improvement of the grating spectrum after annealing, with respect to the one just after inscription, which suggests the application of this method to be employed to improve saturation issues during the photo-inscription process.

  15. Hardening by annealing: insights from different alloys

    International Nuclear Information System (INIS)

    Renk, O; Pippan, R; Hohenwarter, A; Schuh, B; Li, J H

    2015-01-01

    In contrast to the general notion about the annealing behavior of coarse grained materials, hardening phenomena in nanocrystalline materials can occur. Although the phenomena have already been recognized several years ago, the mechanisms behind are still controversially discussed. For example, the influence of solutes segregated to grain boundaries on the strengthening mechanism is unclear. We present a combination of atom probe tomography and mechanical data to reveal the role of segregations to the strengthening. The results show that despite large modifications of the boundary chemistry the mechanical behavior remains widely unaffected. Additionally, it will be shown that hardening upon annealing can only occur below a material-specific grain size threshold value. (paper)

  16. Modular annealing apparatus for in situ reactor vessel annealing and related method of assembly

    International Nuclear Information System (INIS)

    Bau, F.I.; Mavretish, R.S.

    1992-01-01

    This patent describes a method for annealing a nuclear reactor vessel in a containment building. It comprises pre-fabricating a plurality of heater segments at a location outside the containment building; transporting the plurality of heater segments to the containment building; removing the core and internals and storing same; installing temporary shielding for the stored internals; introducing each of the plurality of heater segments through an equipment hatch in the containment building; assembling the plurality of heater segments to form an annealing apparatus; and annealing the reactor vessel

  17. Intelligent medical image processing by simulated annealing

    International Nuclear Information System (INIS)

    Ohyama, Nagaaki

    1992-01-01

    Image processing is being widely used in the medical field and already has become very important, especially when used for image reconstruction purposes. In this paper, it is shown that image processing can be classified into 4 categories; passive, active, intelligent and visual image processing. These 4 classes are explained at first through the use of several examples. The results show that the passive image processing does not give better results than the others. Intelligent image processing, then, is addressed, and the simulated annealing method is introduced. Due to the flexibility of the simulated annealing, formulated intelligence is shown to be easily introduced in an image reconstruction problem. As a practical example, 3D blood vessel reconstruction from a small number of projections, which is insufficient for conventional method to give good reconstruction, is proposed, and computer simulation clearly shows the effectiveness of simulated annealing method. Prior to the conclusion, medical file systems such as IS and C (Image Save and Carry) is pointed out to have potential for formulating knowledge, which is indispensable for intelligent image processing. This paper concludes by summarizing the advantages of simulated annealing. (author)

  18. Influence of Intercritical Annealing Temperature on Mechanical ...

    African Journals Online (AJOL)

    The fracture surfaces of the impact test samples were examined using the scanning electron microscope (SEM). Micros structural evolution of the samples was also examined with an optical microscope. The results showed that all the evaluated mechanical properties were improved by intercritical annealing, with the ...

  19. Finite-time thermodynamics and simulated annealing

    International Nuclear Information System (INIS)

    Andresen, B.

    1989-01-01

    When the general, global optimization technique simulated annealing was introduced by Kirkpatrick et al. (1983), this mathematical algorithm was based on an analogy to the statistical mechanical behavior of real physical systems like spin glasses, hence the name. In the intervening span of years the method has proven exceptionally useful for a great variety of extremely complicated problems, notably NP-problems like the travelling salesman, DNA sequencing, and graph partitioning. Only a few highly optimized heuristic algorithms (e.g. Lin, Kernighan 1973) have outperformed simulated annealing on their respective problems (Johnson et al. 1989). Simulated annealing in its current form relies only on the static quantity 'energy' to describe the system, whereas questions of rate, as in the temperature path (annealing schedule, see below), are left to intuition. We extent the connection to physical systems and take over further components from thermodynamics like ensemble, heat capacity, and relaxation time. Finally we refer to finite-time thermodynamics (Andresen, Salomon, Berry 1984) for a dynamical estimate of the optimal temperature path. (orig.)

  20. influence of intercritical annealing temperature on mechanical

    African Journals Online (AJOL)

    User

    Keywords: intercritical annealing, dual phase steel, mechanical properties, microstructure. 1. INTRODUCTION. Steel, is world's most “advanced” material. It is the most widely used engineering material, essentially due to the fact that it can be manufactured at very competitive cost in large quantities to very precise.

  1. 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...

  2. Scalable effective-temperature reduction for quantum annealers via nested quantum annealing correction

    Science.gov (United States)

    Vinci, Walter; Lidar, Daniel A.

    2018-02-01

    Nested quantum annealing correction (NQAC) is an error-correcting scheme for quantum annealing that allows for the encoding of a logical qubit into an arbitrarily large number of physical qubits. The encoding replaces each logical qubit by a complete graph of degree C . The nesting level C represents the distance of the error-correcting code and controls the amount of protection against thermal and control errors. Theoretical mean-field analyses and empirical data obtained with a D-Wave Two quantum annealer (supporting up to 512 qubits) showed that NQAC has the potential to achieve a scalable effective-temperature reduction, Teff˜C-η , with 0 learning applications. Since we demonstrate that NQAC achieves error correction via a reduction of the effective-temperature of the quantum annealing device, our results address the problem of the "temperature scaling law for quantum annealers," which requires the temperature of quantum annealers to be reduced as problems of larger sizes are attempted to be solved.

  3. Computational Bottlenecks of Quantum Adiabatic Annealing

    Science.gov (United States)

    Knysh, Sergey

    2015-03-01

    Quantum annealing in a transverse field with rate dΓ / dt inversely proportional to the system size N suppresses non-adiabatic transitions for fully connected spin glass such as the Sherrington-Kirpatrick (SK) model at the quantum critical point. This alone is not sufficient to ensure that the problem is solvable in polynomial time. I conjecture the appearance of small gaps associated with macroscopic tunneling events deep in the spin glass phase. This effect is demonstrated rigorously for the annealing of a toy model that shares a set of crtical exponents with SK model: Hopfield network with two Gaussian patterns. It presents with 0 . 15 lnN additional bottlenecks with gaps that scale as a stretched exponential exp[-c (NΓ) 3 / 4]. Further, I extend the analysis to the ρ-landscapes model (random energy model with correlations) which more faithfully represents real spin glasses.

  4. Dynamical Frustration in ANNNI Model and Annealing

    Science.gov (United States)

    Sen, Parongama; Das, Pratap K.

    Simulated annealing is usually applied to systems with frustration, like spin glasses and optimisation problems, where the energy landscape is complex with many spurious minima. There are certain other systems, however, which have very simple energy landscape picture and ground states, but still the system fails to reach its ground state during a energy-lowering dynamical process. This situation corresponds to "dynamical frustration ". We have specifically considered the case of the axial next nearest neighbour (ANNNI) chain, where such a situation is encountered. In Sect. II, we elaborate the notion of dynamic frustration with examples and in Sect. III, the dynamics in ANNNI model is discussed in detail. The results of application of the classical and quantum annealing are discussed in Sects. IV and V. Summary and some concluding comments are given in the last section.

  5. Simulated annealing algorithm for optimal capital growth

    Science.gov (United States)

    Luo, Yong; Zhu, Bo; Tang, Yong

    2014-08-01

    We investigate the problem of dynamic optimal capital growth of a portfolio. A general framework that one strives to maximize the expected logarithm utility of long term growth rate was developed. Exact optimization algorithms run into difficulties in this framework and this motivates the investigation of applying simulated annealing optimized algorithm to optimize the capital growth of a given portfolio. Empirical results with real financial data indicate that the approach is inspiring for capital growth portfolio.

  6. Optimization Via Open System Quantum Annealing

    Science.gov (United States)

    2016-01-07

    be solved by a quantum evolution from a strong transverse field to a spin glass Hamiltonian (also known as quantum annealing or QA). We have...reduced to Quadratic Unconstrained Binary Optimization (QUBO), which can be solved by a quantum evolution from a strong transverse field to a spin...Excellence grant for Education , Research and Engineering: The number of undergraduates funded by your agreement who graduated during this period and

  7. 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...... for interference alignment. We also show that the iterative leakage minimization algorithm by Gomadam et al. and the alternating minimization algorithm by Peters and Heath, Jr. are instances of our method. Finally, we assess the performance of the proposed algorithm through computer simulations....

  8. Simulated annealing for tensor network states

    International Nuclear Information System (INIS)

    Iblisdir, S

    2014-01-01

    Markov chains for probability distributions related to matrix product states and one-dimensional Hamiltonians are introduced. With appropriate ‘inverse temperature’ schedules, these chains can be combined into a simulated annealing scheme for ground states of such Hamiltonians. Numerical experiments suggest that a linear, i.e., fast, schedule is possible in non-trivial cases. A natural extension of these chains to two-dimensional settings is next presented and tested. The obtained results compare well with Euclidean evolution. The proposed Markov chains are easy to implement and are inherently sign problem free (even for fermionic degrees of freedom). (paper)

  9. 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.

  10. Implantation annealing in GaAs by incoherent light

    International Nuclear Information System (INIS)

    Davies, D.E.; Ryan, T.G.; Soda, K.J.; Comer, J.J.

    1983-01-01

    Implanted GaAs has been successfully activated through concentrating the output of quartz halogen lamps to anneal in times of the order of 1 sec. The resulting layers are not restricted by the reduced mobilities and thermal instabilities of laser annealed GaAs. Better activation can be obtained than with furnace annealing but this generally requires maximum temperatures >= 1050degC. (author)

  11. Benefits of Intercritical Annealing in Quenching and Partitioning Steel

    Science.gov (United States)

    Wang, X.; Liu, L.; Liu, R. D.; Huang, M. X.

    2018-03-01

    Compared to the quenching and partitioning (Q&P) steel produced by full austenization annealing, the Q&P steel produced by the intercritical annealing shows a similar ultimate tensile stress but a larger tensile ductility. This property is attributable to the higher volume fraction and the better mechanical stability of the retained austenite after the intercritical annealing. Moreover, intercritical annealing produces more ferrite and fewer martensite phases in the microstructure, making an additional contribution to a higher work hardening rate and therefore a better tensile ductility.

  12. Magnetic field annealing for improved creep resistance

    Science.gov (United States)

    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.

  13. Superplasticity of Annealed H13 Steel

    Directory of Open Access Journals (Sweden)

    Zhenxin Duan

    2017-07-01

    Full Text Available H13 steel is a widely used hot work die material. A new type of hot working method is imperative to develop complex and precise dies. In this paper, the heat treatment of H13 steel (AISI was carried out by annealing, the final structure is a point or spherical pearlite, and the grain size is about 30–40 μm. The tensile properties of the annealed microstructure were investigated at 650, 750, and 850 °C with the strain rates of 1 × 10−3 s−1, 5 × 10−4 s−1, and 1 × 10−4 s−1. The tensile fracture and microstructure were analyzed by SEM and HREM. The results show that the tensile samples reach superplasticity at the strain rate of 1 × 10−4 s−1 in the temperature range of 750–850 °C. When the temperature is 850 °C, the maximum elongation rate reaches 112.5%. This demonstrates the possibility of making superplastic forming molds. During the tensile process, the refined M23C6 and other high hardness carbides which are dispersed uniformly in the matrix, effectively inhibits grain growth and hinders dislocation movement, leading to the improvement of plasticity.

  14. Mean Field Analysis of Quantum Annealing Correction.

    Science.gov (United States)

    Matsuura, Shunji; Nishimori, Hidetoshi; Albash, Tameem; Lidar, Daniel A

    2016-06-03

    Quantum annealing correction (QAC) is a method that combines encoding with energy penalties and decoding to suppress and correct errors that degrade the performance of quantum annealers in solving optimization problems. While QAC has been experimentally demonstrated to successfully error correct a range of optimization problems, a clear understanding of its operating mechanism has been lacking. Here we bridge this gap using tools from quantum statistical mechanics. We study analytically tractable models using a mean-field analysis, specifically the p-body ferromagnetic infinite-range transverse-field Ising model as well as the quantum Hopfield model. We demonstrate that for p=2, where the phase transition is of second order, QAC pushes the transition to increasingly larger transverse field strengths. For p≥3, where the phase transition is of first order, QAC softens the closing of the gap for small energy penalty values and prevents its closure for sufficiently large energy penalty values. Thus QAC provides protection from excitations that occur near the quantum critical point. We find similar results for the Hopfield model, thus demonstrating that our conclusions hold in the presence of disorder.

  15. Superplasticity of Annealed H13 Steel.

    Science.gov (United States)

    Duan, Zhenxin; Pei, Wen; Gong, Xuebo; Chen, Hua

    2017-07-28

    H13 steel is a widely used hot work die material. A new type of hot working method is imperative to develop complex and precise dies. In this paper, the heat treatment of H13 steel (AISI) was carried out by annealing, the final structure is a point or spherical pearlite, and the grain size is about 30-40 μm. The tensile properties of the annealed microstructure were investigated at 650, 750, and 850 °C with the strain rates of 1 × 10 -3 s -1 , 5 × 10 -4 s -1 , and 1 × 10 -4 s -1 . The tensile fracture and microstructure were analyzed by SEM and HREM. The results show that the tensile samples reach superplasticity at the strain rate of 1 × 10 -4 s -1 in the temperature range of 750-850 °C. When the temperature is 850 °C, the maximum elongation rate reaches 112.5%. This demonstrates the possibility of making superplastic forming molds. During the tensile process, the refined M 23 C₆ and other high hardness carbides which are dispersed uniformly in the matrix, effectively inhibits grain growth and hinders dislocation movement, leading to the improvement of plasticity.

  16. A coherent quantum annealer with Rydberg atoms

    Science.gov (United States)

    Glaetzle, A. W.; van Bijnen, R. M. W.; Zoller, P.; Lechner, W.

    2017-06-01

    There is a significant ongoing effort in realizing quantum annealing with different physical platforms. The challenge is to achieve a fully programmable quantum device featuring coherent adiabatic quantum dynamics. Here we show that combining the well-developed quantum simulation toolbox for Rydberg atoms with the recently proposed Lechner-Hauke-Zoller (LHZ) architecture allows one to build a prototype for a coherent adiabatic quantum computer with all-to-all Ising interactions and, therefore, a platform for quantum annealing. In LHZ an infinite-range spin-glass is mapped onto the low energy subspace of a spin-1/2 lattice gauge model with quasi-local four-body parity constraints. This spin model can be emulated in a natural way with Rubidium and Caesium atoms in a bipartite optical lattice involving laser-dressed Rydberg-Rydberg interactions, which are several orders of magnitude larger than the relevant decoherence rates. This makes the exploration of coherent quantum enhanced optimization protocols accessible with state-of-the-art atomic physics experiments.

  17. 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.

  18. Investigation of annealing-treatment on structural and optical ...

    Indian Academy of Sciences (India)

    Administrator

    This conforms to the results already reported by Moustaghfir et al (2003). A higher annealing tempera- ture enhances the formation of larger and more closely packed crystals. The increase of the refractive index with increasing annealing temperature can be partly attributed to improvement in film quality with the reduction in.

  19. Effect of annealing temperature on the structural–microstructural and ...

    Indian Academy of Sciences (India)

    In order to get good quality reproducible films of Tl : HTSC system, we have studied the different annealing conditions to finally achieve the optimized annealing condition. In the present investigation, Tl–Ca–Ba–Cu–O superconducting films have been prepared on YSZ (100) and MgO (100) single crystal substrates via ...

  20. Effect of isochronal annealing on phase transformation studies of ...

    Indian Academy of Sciences (India)

    Abstract. The effect of isochronal annealing on the phase transformation in iron oxide nanoparticles is reported in this work. Iron oxide nanoparticles were successfully synthesized using an ash supported technique followed by annealing for 2 h at various temperatures between 300 and 700◦C. It was observed using X-ray ...

  1. Effect of annealing treatment on optical properties and ...

    Indian Academy of Sciences (India)

    2018-03-28

    Mar 28, 2018 ... C. UV–visible spectrophotometer showed that the annealing treatment of the first WO3 layer enhanced the transparency of films in the visible region. The innovations of the present study have been based on the annealing of the films and finding an optimum thickness for the Ag film at 12–14 nm.

  2. Effect of heat moisture treatment and annealing on physicochemical ...

    African Journals Online (AJOL)

    Red sorghum starch was physically modified by annealing and heat moisture treatment. The swelling power and solubility increased with increasing temperature range (60-90°), while annealing and heatmoisture treatment decreased swelling power and solubility of starch. Solubility and swelling were pH dependent with ...

  3. Simulated annealing approach for solving economic load dispatch ...

    African Journals Online (AJOL)

    user

    Abstract. This paper presents Simulated Annealing (SA) algorithm for optimization inspired by the process of annealing in ... Various classical optimization techniques were used to solve the ELD problem, for example: lambda iteration approach, ...... Research of fuzzy self-adaptive immune algorithm and its application.

  4. Effect of isochronal annealing on phase transformation studies of ...

    Indian Academy of Sciences (India)

    The effect of isochronal annealing on the phase transformation in iron oxide nanoparticles is reported in this work. Iron oxide nanoparticles were successfully synthesized using an ash supported technique followed by annealing for 2 h at various temperatures between 300 and 700° C. It was observed using X-ray diffraction ...

  5. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Administrator

    The amplitude permeability and magnetic loss of the cores reached the maximum and minimum values, respectively. The magnetic loss of the cores was separated into hysteresis loss and eddy current loss by Stoppels Method which were decreased by the annealing process. Keywords. Reduced iron powders; annealing ...

  6. A note on simulated annealing to computer laboratory scheduling ...

    African Journals Online (AJOL)

    Simulated Annealing algorithm is used in solving real life problem of Computer Laboratory scheduling in order to maximize the use of scarce and insufficient resources. KEY WORDS: Simulated Annealing (SA), Computer Laboratory Scheduling, Statistical Thermodynamics, Energy Function, and Heuristic etc. Global Jnl of ...

  7. Response of neutron-irradiated RPV steels to thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

    1997-03-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the fracture toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results of work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response of several irradiated RPV steels.

  8. Improvements in or relating to laser annealed electronic devices

    International Nuclear Information System (INIS)

    Barraclough, K.G.; Cullis, A.G.; Webber, H.C.

    1981-01-01

    A method of producing laser annealed electronic devices is described. The technique involves irradiating semiconductor material such as silicon or germanium to produce a neutron transmuted semiconductor material and laser annealing a selected region or regions in a slice of the transmuted material to a sub-micron depth. (U.K.)

  9. Effect of annealing on magnetic properties and silicide formation at ...

    Indian Academy of Sciences (India)

    coercivity decreases and remanence increases. The values of remanence of pristine Co/Si and annealed at 300°C are. 0⋅80 and 0⋅98, respectively. 3.3 AFM measurement. Morphological changes of silicide surface during high temperature annealing have been investigated by AFM in terms of the RMS surface roughness.

  10. Stored energy and annealing behavior of heavily deformed aluminium

    DEFF Research Database (Denmark)

    Kamikawa, Naoya; Huang, Xiaoxu; Kondo, Yuka

    2012-01-01

    are quantified such as boundary spacing, misorientation angle and dislocation density for 99.99% aluminium deformed by accumulative roll-bonding to a strain of 4.8. Two different annealing processes have been applied; (i) one-step annealing for 0.5 h at 100-400°C and (ii) two-step annealing for 6 h at 175°C......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...... 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 structure...

  11. Angular filter refractometry analysis using simulated annealing.

    Science.gov (United States)

    Angland, P; Haberberger, D; Ivancic, S T; Froula, D H

    2017-10-01

    Angular filter refractometry (AFR) is a novel technique used to characterize the density profiles of laser-produced, long-scale-length plasmas [Haberberger et al., Phys. Plasmas 21, 056304 (2014)]. A new method of analysis for AFR images was developed using an annealing algorithm to iteratively converge upon a solution. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on the minimization of the χ 2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in an average uncertainty in the density profile of 5%-20% in the region of interest.

  12. Coupled Quantum Fluctuations and Quantum Annealing

    Science.gov (United States)

    Hormozi, Layla; Kerman, Jamie

    We study the relative effectiveness of coupled quantum fluctuations, compared to single spin fluctuations, in the performance of quantum annealing. We focus on problem Hamiltonians resembling the the Sherrington-Kirkpatrick model of Ising spin glass and compare the effectiveness of different types of fluctuations by numerically calculating the relative success probabilities and residual energies in fully-connected spin systems. We find that for a small class of instances coupled fluctuations can provide improvement over single spin fluctuations and analyze the properties of the corresponding class. Disclaimer: This research was funded by ODNI, IARPA via MIT Lincoln Laboratory under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  13. Inferring hierarchical clustering structures by deterministic annealing

    International Nuclear Information System (INIS)

    Hofmann, T.; Buhmann, J.M.

    1996-01-01

    The unsupervised detection of hierarchical structures is a major topic in unsupervised learning and one of the key questions in data analysis and representation. We propose a novel algorithm for the problem of learning decision trees for data clustering and related problems. In contrast to many other methods based on successive tree growing and pruning, we propose an objective function for tree evaluation and we derive a non-greedy technique for tree growing. Applying the principles of maximum entropy and minimum cross entropy, a deterministic annealing algorithm is derived in a meanfield approximation. This technique allows us to canonically superimpose tree structures and to fit parameters to averaged or open-quote fuzzified close-quote trees

  14. Annealing effects on cathodoluminescence of zircon

    Science.gov (United States)

    Tsuchiya, Y.; Nishido, H.; Noumi, Y.

    2011-12-01

    U-Pb zircon dating (e. g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) imaging allows us to recognize internal zones and domains with different chemical compositions and structural disorder at high spatial resolution. The CL of zircon is attributed by various types of emission centers, which are extrinsic ones such as REE impurities and intrinsic ones such as structural defects. Metamictization resulted from radiation damage to the lattice by alpha particles from the decay of U and Th mostly causes an effect on the CL features of zircon as a defect center. However, slightly radiation-damaged zircon, which is almost nondetectable by XRD, has not been characterized using CL method. In this study, annealing effects on CL of zircon has been investigated to clarify a recovery process of the damaged lattice at low radiation dose. A single crystal of zircon from Malawi was selected for CL measurements. It contains HfO2: 2.30 w.t %, U: 241 ppm and Th: 177 ppm. Two plate samples perpendicular to c and a axes were prepared for annealing experiments during 12 hours from room temperature to 1400 degree C. Color CL images were captured using a cold-cathode microscope (Luminoscope: Nuclide ELM-3R). CL spectral measurements were conducted using an SEM (JEOL: JSM-5410) combined with a grating monochromator (Oxford: Mono CL2) to measure CL spectra ranging from 300 to 800 nm in 1 nm steps with a temperature controlled stage. The dispersed CL was collected by a photoncounting method using a photomultiplier tube (Hamamatsu: R2228) and converted to digital data. All CL spectra were corrected for the total instrumental response. Spectral analysis reveals an anisotropy of the CL emission bands related to intrinsic defect center in blue region, radiation-induced defect center from 500 to 700 nm, and trivalent Dy impurity center at 480 and 580 nm, but their relative intensities are almost constant. CL on the

  15. Efficiency of quantum vs. classical annealing in nonconvex learning problems.

    Science.gov (United States)

    Baldassi, Carlo; Zecchina, Riccardo

    2018-02-13

    Quantum annealers aim at solving nonconvex optimization problems by exploiting cooperative tunneling effects to escape local minima. The underlying idea consists of designing a classical energy function whose ground states are the sought optimal solutions of the original optimization problem and add a controllable quantum transverse field to generate tunneling processes. A key challenge is to identify classes of nonconvex optimization problems for which quantum annealing remains efficient while thermal annealing fails. We show that this happens for a wide class of problems which are central to machine learning. Their energy landscapes are dominated by local minima that cause exponential slowdown of classical thermal annealers while simulated quantum annealing converges efficiently to rare dense regions of optimal solutions. Copyright © 2018 the Author(s). Published by PNAS.

  16. 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.

  17. Grain coarsening mechanism of Cu thin films by rapid annealing

    International Nuclear Information System (INIS)

    Sasajima, Yasushi; Kageyama, Junpei; Khoo, Khyoupin; Onuki, Jin

    2010-01-01

    Cu thin films have been produced by an electroplating method using nominal 9N anode and nominal 6N CuSO 4 .5H 2 O electrolyte. Film samples were heat-treated by two procedures: conventional isothermal annealing in hydrogen atmosphere (abbreviated as H 2 annealing) and rapid thermal annealing with an infrared lamp (abbreviated as RTA). After heat treatment, the average grain diameters and the grain orientation distributions were examined by electron backscattering pattern analysis. The RTA samples (400 o C for 5 min) have a larger average grain diameter, more uniform grain distribution and higher ratio of (111) orientation than H 2 annealed samples (400 o C for 30 min). This means that RTA can produce films with coarser and more uniformly distributed grains than H 2 annealing within a short time, i.e. only a few minutes. To clarify the grain coarsening mechanism, grain growth by RTA was simulated using the phase field method. The simulated grain diameter reaches its maximum at a heating rate which is the same order as that in the actual RTA experiment. The maximum grain diameter is larger than that obtained by H 2 annealing with the same annealing time at the isothermal stage as in RTA. The distribution of the misorientation was analyzed which led to a proposed grain growth model for the RTA method.

  18. Annealed Scaling for a Charged Polymer

    International Nuclear Information System (INIS)

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

    2016-01-01

    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

  19. 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....

  20. Structural study of conventional and bulk metallic glasses during annealing

    International Nuclear Information System (INIS)

    Pineda, E.; Hidalgo, I.; Bruna, P.; Pradell, T.; Labrador, A.; Crespo, D.

    2009-01-01

    Metallic glasses with conventional glass-forming ability (Al-Fe-Nd, Fe-Zr-B, Fe-B-Nb compositions) and bulk metallic glasses (Ca-Mg-Cu compositions) were studied by synchrotron X-ray diffraction during annealing throughout glass transition and crystallization temperatures. The analysis of the first diffraction peak position during the annealing process allowed us to follow the free volume change during relaxation and glass transition. The structure factor and the radial distribution function of the glasses were obtained from the X-ray measurements. The structural changes occurred during annealing are analyzed and discussed.

  1. Anisotropic annealing of fission fragments in synthetic quartz

    CERN Document Server

    Sawamura, T; Narita, M

    1999-01-01

    A study on the thermal annealing behavior of fission fragments in synthetic quartz crystals was performed for application of synthetic quartz to track detectors under high temperature circumstances: x-, y-, and z-cut quartz plates were exposed to fission fragments from sup 2 sup 5 sup 2 Cf and were annealed up to 750 deg. C. It was found that track retention depended on the crystallographic structure: the annealing temperature, where the number of etched tracks was sharply reduced, was 550 deg. C for the x- and y-cut plates and 750 deg. C for z-cut plates. Track sizes decrease and disperse with reductions in the track retention.

  2. Radiation damage and annealing in plutonium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

    2017-12-01

    Plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an off-normal color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, Thermogravimetric/Differential Thermal Analysis and X-ray Diffraction evaluations were conducted to determine the plutonium’s crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial Thermogravimetric/Differential Thermal analyses, it was discovered that an exothermic event occurred within the material near 414°C. X-ray Diffraction analyses were conducted on the annealed tetrafluoride. The X-ray Diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414°C event. The following commentary describes the series of Thermogravimetric/Differential Thermal and X-ray Diffraction analyses that were conducted as part of this investigation at PNNL, in collaboration with the University of Utah Nuclear Engineering Program.

  3. 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.

  4. Structural changes during annealing of GaInAsN

    International Nuclear Information System (INIS)

    Kurtz, Sarah; Webb, J.; Gedvilas, L.; Friedman, D.; Geisz, J.; Olson, J.; King, R.; Joslin, D.; Karam, N.

    2001-01-01

    The alloy GaInAsN has great potential as a lower-band-gap material lattice matched to GaAs, but there is little understanding of what causes its poor optoelectronic properties and why these improve with annealing. This study provides information about the structural changes that occur when GaInAsN is annealed. The Fourier transform infrared spectra exhibit two primary features: a triplet at ∼470 cm-1 (Ga--N stretch) and two or three bands at ∼3100 cm-1 (N--H stretch). The change in the Ga--N stretch absorption can be explained if the nitrogen environment is converted from NGa 4 to NInGa 3 after annealing. The N--H stretch is also changed after annealing, implying a second, and unrelated, structural change

  5. Performance of two different quantum annealing correction codes

    Science.gov (United States)

    Mishra, Anurag; Albash, Tameem; Lidar, Daniel A.

    2016-02-01

    Quantum annealing is a promising approach for solving optimization problems, but like all other quantum information processing methods, it requires error correction to ensure scalability. In this work, we experimentally compare two quantum annealing correction (QAC) codes in the setting of antiferromagnetic chains, using two different quantum annealing processors. The lower-temperature processor gives rise to higher success probabilities. The two codes differ in a number of interesting and important ways, but both require four physical qubits per encoded qubit. We find significant performance differences, which we explain in terms of the effective energy boost provided by the respective redundantly encoded logical operators of the two codes. The code with the higher energy boost results in improved performance, at the expense of a lower-degree encoded graph. Therefore, we find that there exists an important trade-off between encoded connectivity and performance for quantum annealing correction codes.

  6. 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.

  7. Simulated annealing image reconstruction for positron emission tomography

    International Nuclear Information System (INIS)

    Sundermann, E.; Lemahieu, I.; Desmedt, P.

    1994-01-01

    In Positron Emission Tomography (PET) images have to be reconstructed from moisy projection data. The noise on the PET data can be modeled by a Poison distribution. In this paper, we present the results of using the simulated annealing technique to reconstruct PET images. Various parameter settings of the simulated annealing algorithm are discussed and optimized. The reconstructed images are of good quality and high contrast, in comparison to other reconstruction techniques. (authors)

  8. Far-infrared spectroscopy of thermally annealed tungsten silicide films

    International Nuclear Information System (INIS)

    Amiotti, M.; Borghesi, A.; Guizzetti, G.; Nava, F.; Santoro, G.

    1991-01-01

    The far-infrared transmittance spectrum of tungsten silicide has been observed for the first time. WSi 2 polycrystalline films were prepared by coevaporation and chemical-vapour deposition on silicon wafers, and subsequently thermally annealed at different temperatures. The observed structures are interpreted, on the basis of the symmetry properties of the crystal, such as infrared-active vibrational modes. Moreover, the marked lineshape dependence on annealing temperature enables this technique to analyse the formation of the solid silicide phases

  9. Population annealing: Theory and application in spin glasses

    OpenAIRE

    Wang, Wenlong; Machta, Jonathan; Katzgraber, Helmut G.

    2015-01-01

    Population annealing is an efficient sequential Monte Carlo algorithm for simulating equilibrium states of systems with rough free energy landscapes. The theory of population annealing is presented, and systematic and statistical errors are discussed. The behavior of the algorithm is studied in the context of large-scale simulations of the three-dimensional Ising spin glass and the performance of the algorithm is compared to parallel tempering. It is found that the two algorithms are similar ...

  10. Conventional treatment planning optimization using simulated annealing

    International Nuclear Information System (INIS)

    Morrill, S.M.; Langer, M.; Lane, R.G.

    1995-01-01

    Purpose: Simulated annealing (SA) allows for the implementation of realistic biological and clinical cost functions into treatment plan optimization. However, a drawback to the clinical implementation of SA optimization is that large numbers of beams appear in the final solution, some with insignificant weights, preventing the delivery of these optimized plans using conventional (limited to a few coplanar beams) radiation therapy. A preliminary study suggested two promising algorithms for restricting the number of beam weights. The purpose of this investigation was to compare these two algorithms using our current SA algorithm with the aim of producing a algorithm to allow clinically useful radiation therapy treatment planning optimization. Method: Our current SA algorithm, Variable Stepsize Generalized Simulated Annealing (VSGSA) was modified with two algorithms to restrict the number of beam weights in the final solution. The first algorithm selected combinations of a fixed number of beams from the complete solution space at each iterative step of the optimization process. The second reduced the allowed number of beams by a factor of two at periodic steps during the optimization process until only the specified number of beams remained. Results of optimization of beam weights and angles using these algorithms were compared using a standard cadre of abdominal cases. The solution space was defined as a set of 36 custom-shaped open and wedged-filtered fields at 10 deg. increments with a target constant target volume margin of 1.2 cm. For each case a clinically-accepted cost function, minimum tumor dose was maximized subject to a set of normal tissue binary dose-volume constraints. For this study, the optimized plan was restricted to four (4) fields suitable for delivery with conventional therapy equipment. Results: The table gives the mean value of the minimum target dose obtained for each algorithm averaged over 5 different runs and the comparable manual treatment

  11. Thermalization, Freeze-out, and Noise: Deciphering Experimental Quantum Annealers

    Science.gov (United States)

    Marshall, Jeffrey; Rieffel, Eleanor G.; Hen, Itay

    2017-12-01

    By contrasting the performance of two quantum annealers operating at different temperatures, we address recent questions related to the role of temperature in these devices and their function as "Boltzmann samplers." Using a method to reliably calculate the degeneracies of the energy levels of large-scale spin-glass instances, we are able to estimate the instance-dependent effective temperature from the output of annealing runs. Our results corroborate the "freeze-out" picture which posits two regimes, one in which the final state corresponds to a Boltzmann distribution of the final Hamiltonian with a well-defined "effective temperature" determined at a freeze-out point late in the annealing schedule, and another regime in which such a distribution is not necessarily expected. We find that the output distributions of the annealers do not, in general, correspond to a classical Boltzmann distribution for the final Hamiltonian. We also find that the effective temperatures at different programing cycles fluctuate greatly, with the effect worsening with problem size. We discuss the implications of our results for the design of future quantum annealers to act as more-effective Boltzmann samplers and for the programing of such annealers.

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

    International Nuclear Information System (INIS)

    Santoro, Giuseppe E; Tosatti, Erio

    2006-01-01

    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)

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

    Indian Academy of Sciences (India)

    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 ...

  14. Rapid hardening induced by electric pulse annealing in nanostructured pure aluminum

    DEFF Research Database (Denmark)

    Zeng, Wei; Shen, Yao; Zhang, Ning

    2012-01-01

    Nanostructured pure aluminum was fabricated by heavy cold-rolling and then subjected to recovery annealing either by applying electric pulse annealing or by traditional air furnace annealing. Both annealing treatments resulted in an increase in yield strength due to the occurrence of a “dislocation...

  15. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing.

    Science.gov (United States)

    Lundström, H

    2015-08-01

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  16. Liquid nitrogen enhancement of partially annealed fission tracks in glass

    International Nuclear Information System (INIS)

    Pilione, L.J.; Gold, D.P.

    1976-01-01

    It is known that the number density of fission tracks in solids is reduced if the sample is heated before chemical etching, and the effect of annealing must be allowed for before an age can be assigned to the sample. The extent of annealing can be determined by measuring the reduction of track parameters (diameter and/or length) and comparison with unannealed tracks. Correct ages can be obtained by careful calibration studies of track density reduction against track diameter or length reduction at different annealing temperatures and times. For crystallised minerals, however, the resulting correction techniques are not generally valid. In the experimental work described glass samples were partially annealed and then immersed in liquid N 2 for various periods, and it was shown that the properties of the glass and the track parameters could be altered so as to observe tracks that would normally be erased by annealing. The results of track density measurements against liquid N 2 immersion times are shown graphically. A gain of about 40% was achieved after 760 hours immersion time. The size of the tracks was not noticeably affected by the immersion. It was thought that thermal shock might be the cause of the track enhancement, but it was found that repeated immersion for about 2 hours did not lead to an increase in track density. Other studies suggest that the mechanism that erases the tracks through annealing may be partially reversed when the temperature of the sample is significantly lowered for a sufficient length of time. Further work is under way to find whether or not the process of enhancement is a reversal of the annealing process. Similar enhancement effects using liquid N 2 have been observed for d-particle tracks in polycarbonate detectors. (U.K.)

  17. 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.

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:26053973

  19. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  20. Partially Annealed Disorder and Collapse of Like-Charged Macroions

    Science.gov (United States)

    Mamasakhlisov, Yevgeni S.; Naji, Ali; Podgornik, Rudolf

    2008-11-01

    Charged systems with partially annealed charge disorder are investigated using field-theoretic and replica methods. Charge disorder is assumed to be confined to macroion surfaces surrounded by a cloud of mobile neutralizing counterions in an aqueous solvent. A general formalism is developed by assuming that the disorder is partially annealed (with purely annealed and purely quenched disorder included as special cases), i.e., we assume in general that the disorder undergoes a slow dynamics relative to fast-relaxing counterions making it possible thus to study the stationary-state properties of the system using methods similar to those available in equilibrium statistical mechanics. By focusing on the specific case of two planar surfaces of equal mean surface charge and disorder variance, it is shown that partial annealing of the quenched disorder leads to renormalization of the mean surface charge density and thus a reduction of the inter-plate repulsion on the mean-field or weak-coupling level. In the strong-coupling limit, charge disorder induces a long-range attraction resulting in a continuous disorder-driven collapse transition for the two surfaces as the disorder variance exceeds a threshold value. Disorder annealing further enhances the attraction and, in the limit of low screening, leads to a global attractive instability in the system.

  1. 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. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Enhancing quantum annealing performance for the molecular similarity problem

    Science.gov (United States)

    Hernandez, Maritza; Aramon, Maliheh

    2017-05-01

    Quantum annealing is a promising technique which leverages quantum mechanics to solve hard optimization problems. Considerable progress has been made in the development of a physical quantum annealer, motivating the study of methods to enhance the efficiency of such a solver. In this work, we present a quantum annealing approach to measure similarity among molecular structures. Implementing real-world problems on a quantum annealer is challenging due to hardware limitations such as sparse connectivity, intrinsic control error, and limited precision. In order to overcome the limited connectivity, a problem must be reformulated using minor-embedding techniques. Using a real data set, we investigate the performance of a quantum annealer in solving the molecular similarity problem. We provide experimental evidence that common practices for embedding can be replaced by new alternatives which mitigate some of the hardware limitations and enhance its performance. Common practices for embedding include minimizing either the number of qubits or the chain length and determining the strength of ferromagnetic couplers empirically. We show that current criteria for selecting an embedding do not improve the hardware's performance for the molecular similarity problem. Furthermore, we use a theoretical approach to determine the strength of ferromagnetic couplers. Such an approach removes the computational burden of the current empirical approaches and also results in hardware solutions that can benefit from simple local classical improvement. Although our results are limited to the problems considered here, they can be generalized to guide future benchmarking studies.

  3. Efficient Embedding of Integer Programming Problems on Quantum Annealers

    Science.gov (United States)

    Venturelli, Davide; Trummer, Immanuel

    Quantum Annealers are being considered as a possible platform to solve challenging Integer Optimization Problems (IOP). Hard-coding an IOP as an Ising model onto an annealer is however no easy task due to the severe restrictions imposed mostly by the connectivity of the graph implemented by the hardware architecture, as it has widely discussed for the D-Wave machines. The current approaches employ graph minor embedding algorithms that require a significant overhead of resources (number of qubits, computing power) with respect to the number of logical variables in the IOP. This overhead is arguably the primary problems for practitioners of quantum annealing. We present a new method to deterministically embed an arbitrary IOP in a generic class of annealing chip layouts such that the asymptotic scaling beats all the current methods. It is shown on the latest D-Wave chips to allow programming of problems, relevant for database and space sciences, with approximately 5-10x more variables with respect to the published approaches. The method is efficient in the sense that a valid embedding can be computed at run-time in polynomial time. The discussed methods can inform the design of next-generation of quantum annealers.

  4. Formability of Annealed Ni-Ti Shape Memory Alloy Sheet

    Science.gov (United States)

    Fann, K. J.; Su, J. Y.; Chang, C. H.

    2018-03-01

    Ni-Ti shape memory alloy has two specific properties, superelasiticity and shape memory effect, and thus is widely applied in diverse industries. To extend its application, this study attempts to investigate the strength and cold formability of its sheet blank, which is annealed at various temperatures, by hardness test and by Erichsen-like cupping test. As a result, the higher the annealing temperature, the lower the hardness, the lower the maximum punch load as the sheet blank fractured, and the lower the Erichsen-like index or the lower the formability. In general, the Ni-Ti sheet after annealing has an Erichsen-like index between 8 mm and 9 mm. This study has also confirmed via DSC that the Ni-Ti shape memory alloy possesses the austenitic phase and shows the superelasticity at room temperature.

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

    International Nuclear Information System (INIS)

    Hasenack, C.M.

    1986-01-01

    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 1200 0 C, 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) [pt

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

    International Nuclear Information System (INIS)

    Jackson, D.A.; Malik, S.N.

    1997-01-01

    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

  7. Morphology and annealing kinetics of ion tracks in minerals

    Directory of Open Access Journals (Sweden)

    Ewing R. C.

    2012-10-01

    Full Text Available We have studied the morphology and annealing kinetics of ion tracks in Durango apatite using synchrotron small angle X-ray scattering. The non-destructive, artefact-free technique enables us to determine the track radii with a resolution of fractions of a nanometre. The tracks were generated using different heavy ions with energies between 185 MeV and 2.6 GeV. The track morphology is consistent with the formation of long cylindrical amorphous tracks. The annealing kinetics, measured by SAXS in combination with ex situ and in situ annealing experiments, suggests structural relaxation followed by recrystallisation of the damaged material. The measurement methodology shown here provides a new means for in-depth studies of ion-track formation in minerals under a wide variety of geological conditions.

  8. 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.

  9. Mean field annealing approach to large residual-statics estimation

    Science.gov (United States)

    Cary, Peter W.; Upham, Warren

    1993-12-01

    We present a new method for solving the large residual-statics problem, called mean field annealing, which may be capable of overcoming some of the limitations of stochastic methods. Mean field annealing is a global-search method that is governed by a purely deterministic set of equations. The mean field annealing method approaches global optimization problems in a fundamentally different way from stochastic global-search methods. The mean field approach never samples individual trial solutions in model space. Instead, the mean field equations, which are solved at successively lower temperatures with a fixed-point method, involve solving for the probability distributions of each variable rather than solving for the variables themselves. The probability distribution of each variable is resolved separately by replacing all other variables that occur in the energy function by their expectation values.

  10. Doped ZnO nanowires obtained by thermal annealing.

    Science.gov (United States)

    Shan, C X; Liu, Z; Wong, C C; Hark, S K

    2007-02-01

    Doped ZnO nanowires were prepared in a very simple and inexpensive thermal annealing method using ZnSe nanowires as a precursor. As doped, P doped, and As/P codoped ZnO nanowires were obtained in this method. X-ray diffraction shows that the zincblende ZnSe nanowires were converted to doped wurtzite ZnO nanowires. The incorporation of the dopants was confirmed by energy dispersive X-ray spectroscopy. The doping concentration could be adjusted by changing the annealing temperature and duration. Scanning electron microscopy indicated that the morphology of the ZnSe nanowires was essentially retained after the annealing and doping process. Photoluminescence spectroscopy also verified the incorporation of the dopants into the nanowires.

  11. Phase annealing for the conditional simulation of spatial random fields

    Science.gov (United States)

    Hörning, S.; Bárdossy, A.

    2018-03-01

    Simulated annealing (SA) is a popular geostatistical simulation method as it provides great flexibility. In this paper possible problems of conditioning its realizations are discussed. A statistical test to recognize whether the observations are well embedded in their simulated neighborhood or not is developed. A new simulated annealing method, phase annealing (PA), is presented which makes it possible to avoid poor embedding of observations. PA is based on the Fourier representation of the spatial field. Instead of the individual pixel values, phases corresponding to different Fourier components are modified (i.e. shifted) in order to match prescribed statistics. The method treats neighborhoods together and thus avoids singularities at observation locations. It is faster than SA and can be used for the simulation of high resolution fields. Examples demonstrate the applicability of the method.

  12. 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.

  13. Chaotic Multiquenching Annealing Applied to the Protein Folding Problem

    Directory of Open Access Journals (Sweden)

    Juan Frausto-Solis

    2014-01-01

    Full Text Available The Chaotic Multiquenching Annealing algorithm (CMQA is proposed. CMQA is a new algorithm, which is applied to protein folding problem (PFP. This algorithm is divided into three phases: (i multiquenching phase (MQP, (ii annealing phase (AP, and (iii dynamical equilibrium phase (DEP. MQP enforces several stages of quick quenching processes that include chaotic functions. The chaotic functions can increase the exploration potential of solutions space of PFP. AP phase implements a simulated annealing algorithm (SA with an exponential cooling function. MQP and AP are delimited by different ranges of temperatures; MQP is applied for a range of temperatures which goes from extremely high values to very high values; AP searches for solutions in a range of temperatures from high values to extremely low values. DEP phase finds the equilibrium in a dynamic way by applying least squares method. CMQA is tested with several instances of PFP.

  14. 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.

  15. Microstructural characterization of intercritically annealed low alloy PM steels

    International Nuclear Information System (INIS)

    Gueral, A.; Tekeli, S.

    2007-01-01

    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

  16. Modernization of two gas-fired shaft annealing furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Barthof, G.; Porst, G.; Raczek, S.

    1986-04-01

    The objective was to modernize two existing shaft-type annealing furnaces used for the heat treatment of grey iron castings with the aim of reducing the consumption of gaseous fuel, minimize the formation of scale, decrease maintenance expense and apply more automatic control to the annealing process. This was to be achieved by an optimum combination of new types of construction materials and advanced firing and control equipment. The author describes the furnace in its condition prior to and after reconstruction. The operating results obtained after reconstruction were found to justify the costs incurred. The payback period is roughly one year.

  17. Dependence of boron cluster dissolution on the annealing ambient

    International Nuclear Information System (INIS)

    Radic, Ljubo; Lilak, Aaron D.; Law, Mark E.

    2002-01-01

    Boron is introduced into silicon via implantation to form p-type layers. This process creates damage in the crystal that upon annealing causes enhanced diffusion and clustering of the boron layer. Reactivation of the boron is not a well-understood process. In this letter we experimentally investigate the effect of the annealing ambient on boron reactivation kinetics. An oxidizing ambient which injects silicon interstitials is compared to an inert ambient. Contrary to published theory, an excess of interstitials does not accelerate the reactivation process

  18. A theoretical comparison of evolutionary algorithms and simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Hart, W.E.

    1995-08-28

    This paper theoretically compares the performance of simulated annealing and evolutionary algorithms. Our main result is that under mild conditions a wide variety of evolutionary algorithms can be shown to have greater performance than simulated annealing after a sufficiently large number of function evaluations. This class of EAs includes variants of evolutionary strategie and evolutionary programming, the canonical genetic algorithm, as well as a variety of genetic algorithms that have been applied to combinatorial optimization problems. The proof of this result is based on a performance analysis of a very general class of stochastic optimization algorithms, which has implications for the performance of a variety of other optimization algorithm.

  19. Increased electrical conductivity of peptides through annealing process

    Directory of Open Access Journals (Sweden)

    Seok Daniel Namgung

    2017-08-01

    Full Text Available Biocompatible biologically occurring polymer is suggested as a component of human implantable devices since conventional inorganic materials are apt to trigger inflammation and toxicity problem within human body. Peptides consisting of aromatic amino acid, tyrosine, are chosen, and enhancement on electrical conductivity is studied. Annealing process gives rise to the decrease on resistivity of the peptide films and the growth of the carrier concentration is a plausible reason for such a decrease on resistivity. The annealed peptides are further applied to an active layer of field effect transistor, in which low on/off current ratio (∼10 is obtained.

  20. 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

  1. Effect of annealing on field emission properties of nanodiamond coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, C.X., E-mail: zhaicatty@126.co [School of Information Science and Technology, Northwest University, Xi' an 710127, Shaanxi (China); Yun, J.N.; Zhao, L.L.; Zhang, Z.Y.; Wang, X.W.; Chen, Y.Y. [School of Information Science and Technology, Northwest University, Xi' an 710127, Shaanxi (China)

    2011-03-01

    Field electron emission of detonation nanodiamond (ND) coated on a titanium substrate by electrophoretic deposition is investigated. It is found that thermal annealing can significantly improve the field emission properties of the ND layer, which can be mainly attributed to the formation of the TiC phase between diamond and Ti. The first-principles calculated results show that the formation of transition layers can lower the interface barrier and enhance the field electron emission of ND coating. Besides, the transformation of diamond to graphite after annealing has been revealed by Raman spectra. This transformation also benefits the electron emission enhancement.

  2. Crystallographic refinement by simulated annealing: Application to crambin

    International Nuclear Information System (INIS)

    Bruenger, A.T.; Yale Univ., New Haven, CT; Harvard Univ., Cambridge, MA; Karplus, M.; Petsko, G.A.

    1989-01-01

    A detailed description of the method of crystallographic refinement by simulated annealing is presented. To test the method, it has been applied to a 1.5 A resolution X-ray structure of crambin. The dependence of the success of the simulated annealing protocol with respect to the temperature of the heating stage is discussed. Optimal success is achieved at relatively high temperatures. Regardless of the protocol used, the molecular-dynamics refined structure always yields an improved R factor compared with restrained least-squares refinement without manual re-fitting. The differences between the various refined structures and the corresponding electron density maps are discussed. (orig.)

  3. 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

    Electrodeposition results in a non-equilibrium state of the as-deposited nanocrystalline microstructure, which evolves towards an energetically more favorable state as a function of time and/or temperature upon deposition. Real-time investigation of the evolving microstructure in copper, silver......-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...... and 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...

  4. Ball milling and annealing of Co-50 at% W Powders

    CSIR Research Space (South Africa)

    Bolokang, AS

    2013-04-01

    Full Text Available annealing of unmilled compacts yielded metastable phases. Upon 10 and 20 h ball milling of Co-W powder, no alloying was obtained. Although milling did not yield significant crystal changes in W and Co ground state struc- tures, its effect is evident during...

  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

  6. 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

  7. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process, the cracks ...

  8. The effects of Mg incorporation and annealing temperature on the ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 88; Issue 2. The effects of Mg incorporation and annealing temperature on the physicochemical properties and antibacterial activity against {\\it Listeria monocytogenes} of ZnO nanoparticles. NIMA SHADAN ALI ABDOLAHZADEH ZIABARI RAFIEH MERAAT KAMYAR ...

  9. 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

  10. Effect of annealing atmosphere on microstructure, optical and ...

    Indian Academy of Sciences (India)

    2018-02-05

    Feb 5, 2018 ... Indian Academy of Sciences https://doi.org/10.1007/s12034-017-1542-6. Effect of annealing atmosphere on microstructure, optical and electronic properties of spray-pyrolysed In-doped Zn(O,S) thin films. MARGI JANI, DHYEY RAVAL, RANJAN KUMAR PATI, INDRAJIT MUKHOPADHYAY and ABHIJIT RAY.

  11. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process,.

  12. Correction of measured multiplicity distributions by the simulated annealing method

    International Nuclear Information System (INIS)

    Hafidouni, M.

    1993-01-01

    Simulated annealing is a method used to solve combinatorial optimization problems. It is used here for the correction of the observed multiplicity distribution from S-Pb collisions at 200 GeV/c per nucleon. (author) 11 refs., 2 figs

  13. Effects of nitrogen annealing on surface structure, silicide formation ...

    Indian Academy of Sciences (India)

    pure) bulk cobalt which was held in water cooled copper cru- cibles. All the samples were coated with 50 Å of cobalt at a rate of 0·1 Å/s. The deposition rate was ... sivity and due to the resultant shortage in the cobalt atoms, monosilicides are formed instead of di-metal silicides. At annealing temperatures higher than 600.

  14. Hafnium implanted in iron 1. Lattice location and annealing behavior

    NARCIS (Netherlands)

    de Bakker, J.M.G.J.; Pleiter, F; Smulders, P.J M

    1993-01-01

    Perturbed angular correlation, Rutherford backscattering and channelling experiments were conducted to study the lattice location and annealing behaviour of 110 keV hafnium ions implanted into iron single crystals. It was found that a fraction of 11-25% of the implanted hafnium atoms are located at

  15. 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...

  16. Influence of degree of deformation in rolling on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    The hardness, strength and electrical conductivity were measured and X-ray and DSC analyses performed. Anneal hardening effect was observed in the alloy in the temperature range 180–300°C, followed by an increase in the electrical conductivity. The amount of strengthening increases with increasing degree of prior.

  17. Coupled Qubits for Next Generation Quantum Annealing: Improving Coherence

    Science.gov (United States)

    Weber, Steven; Samach, Gabriel; Hover, David; Rosenberg, Danna; Yoder, Jonilyn; Kim, David K.; Kerman, Andrew; Oliver, William D.

    Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times, limited primarily by the use of large persistent currents. Here, we examine an alternative approach, using flux qubits with smaller persistent currents and longer coherence times. We demonstrate tunable coupling, a basic building-block for quantum annealing, between two such qubits. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  18. Thermal annealing of femtosecond laser written structures in silica glass

    NARCIS (Netherlands)

    Witcher, J.J.; Reichman, W.B.; Fletcher, L.B.; Troy, N.W.; Krol, D.M.

    2013-01-01

    We have investigated the thermal stability of femtosecond laser modification inside fused silica. Raman and FL spectroscopy show that fs-laser induced non-bridging oxygen hole center (NBOHC) defects completely disappear at 300 °C, whereas changes in Si-O ring structures only anneal out after heat

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

    International Nuclear Information System (INIS)

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1995-01-01

    The irradiation embrittlement of nuclear reactor pressure vessels (RPV) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. The objective of this work was to analyze the pertinent data and develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy due to annealing. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Models were developed based on a combination of statistical techniques, including pattern recognition and transformation analysis, and the current understanding of the mechanisms governing embrittlement and recovery. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and a surrogate hardness data base. This work demonstrates that microhardness recovery is i good surrogate for shift recovery and that there is a high level of consistency between he observed annealing trends and fundamental models of embrittlement and recovery processes

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

    International Nuclear Information System (INIS)

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1998-01-01

    The irradiation embrittlement of nuclear reactor pressure vessels (RPV) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. The objective of this work was to analyze the pertinent data and develop quantitative models for estimating the recovery in 41 J (30 ft-lb) Charpy transition temperature (TT) and Charpy upper shelf energy (USE) due to annealing. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Models were developed based on a combination of statistical techniques, including pattern recognition and transformation analysis, and the current understanding of the mechanisms governing embrittlement and recovery. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and a surrogate hardness data base. This work demonstrates that microhardness recovery is a good surrogate for shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes. (orig.)

  1. Effect of annealing on phase transition in poly (vinylidene fluoride ...

    Indian Academy of Sciences (India)

    The -phase poly (vinylidene fluoride) (PVDF) films are usually prepared using dimethyl sulfoxide (DMSO) solvent, regardless of preparation temperature. Here we report the crystallization of both and -phase PVDF films by varying preparation temperature using DMSO solvent. The -phase PVDF films were annealed ...

  2. Influence of degree of deformation in rolling on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of degree of deformation in rolling on anneal hardening effect of a cast copper alloy. SVETLANA NESTOROVIC*, DESIMIR MARKOVIC and LJUBICA IVANIC. Technical Faculty Bor, University of Belgrade, Belgrade, Yugoslavia. MS received 15 May 2003. Abstract. This paper reports results of investigations carried ...

  3. 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....

  4. Direct Immersion Annealing of Block Copolymer Thin Films

    Science.gov (United States)

    Karim, Alamgir

    We demonstrate ordering of thin block copolymer (BCP) films via direct immersion annealing (DIA) at enhanced rate leading to stable morphologies. The BCP films are immersed in carefully selected mixtures of good and marginal solvents that can impart enhanced polymer mobility, while inhibiting film dissolution. DIA is compatible with roll-to-roll assembly manufacturing and has distinct advantages over conventional thermal annealing and batch processing solvent-vapor annealing methods. We identify three solvent composition-dependent BCP film ordering regimes in DIA for the weakly interacting polystyrene -poly(methyl methacrylate) (PS -PMMA) system: rapid short range order, optimal long-range order, and a film instability regime. Kinetic studies in the ``optimal long-range order'' processing regime as a function of temperature indicate a significant reduction of activation energy for BCP grain growth compared to oven annealing at conventional temperatures. An attractive feature of DIA is its robustness to ordering other BCP (e.g. PS-P2VP) and PS-PMMA systems exhibiting spherical, lamellar and cylindrical ordering. Inclusion of nanoparticles in these films at high concentrations and fast ordering kinetics study with neutron reflectivity and SANS will be discussed. This is (late) Contributed Talk Abstract for Dillon Medal Symposium at DPOLY - discussed with DPOLY Chair Dvora Perahia.

  5. Dielectric properties of plasma sprayed silicates subjected to additional annealing

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Sedláček, J.; Nevrlá, Barbara; Neufuss, Karel

    2017-01-01

    Roč. 10, č. 2 (2017), s. 105-114 ISSN 2008-2134 Institutional support: RVO:61389021 Keywords : Annealing * Dielectric properties * Plasma spraying * Silicates * Electrical properties * Insulators Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films http://pccc.icrc.ac.ir/Articles/1/18/990/

  6. Infrared absorption studies of the annealing of irradiated diamonds

    International Nuclear Information System (INIS)

    Woods, G.S.

    1984-01-01

    Natural (types Ia and IIa) and synthetic (type Ib) diamonds have been irradiated with energetic electrons and neutrons and then heated at temperatures up to 1400 deg C. Attendant changes in the infrared absorption spectra, especially above the Raman frequency (1332 cm -1 ), have been monitored. The most prominent absorption to develop in the infrared region proper, on annealing both type Ia and type Ib specimens, whether electron- or neutron-irradiated is the H1a line at 1450 cm -1 . Measurements taken of neutron-irradiated type Ia specimens show that the strength of this line is specimen-dependent, and that it is a linear function of radiation dose. Isochronal annealing studies show that the onset of the line occurs during heating at 250 deg C for type Ia specimens and at 650 deg C for type Ib specimens. The absorption begins to weaken during heating at 1100 deg C, but it is very persistent, surviving an anneal of 4 hours at 1400 deg C, albeit with diminished intensity. Three other weaker lines at 1438, 1358 and 1355 cm -1 develop with the 1450 cm -1 line, but differ from it and from each other in subsequent annealing behaviour. Other lines were observed; these are reported and discussed. (author)

  7. Effect of annealing atmosphere on microstructure, optical and ...

    Indian Academy of Sciences (India)

    61

    Effect of annealing atmosphere on microstructure, optical and electronic properties of spray pyrolysed indium doped Zn(O,S) thin films. Margi Jani1, DhyeyRaval1,Ranjan Kumar Pati1, Indrajit Mukhopadhyay1. andAbhijit Ray1*. 1Solar Research and Development Center, School of Solar Energy, PanditDeendayal.

  8. Property change during nanosecond pulse laser annealing of ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 35; Issue 3. Property change during nanosecond pulse laser annealing of amorphous NiTi thin film. S K Sadrnezhaad Noushin Yasavol Mansoureh Ganjali Sohrab Sanjabi. Volume 35 Issue 3 June 2012 pp 357-364 ...

  9. 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...

  10. Low temperature electron irradiation and annealing of pure cadmium

    International Nuclear Information System (INIS)

    Menendez, M.A.

    1979-01-01

    Cadmium after electron irradiation below 2 0 K, was studied and the damage production rate in Dc was found to be (4.13 +- .16) x 10 -26 Ωcm/(e - /cm 2 ) for irradiation with 2.5 MeV electrons at 1.5 0 K. New annealing peaks were observed at 1.825 0 K and at about 2 0 K with activation energies of (2.6 +- .1) x 10 -3 eV and (2.77 +- .34) x 10 -3 eV, respectively. The peak at about 2 0 K exhibits dose-dependence, but it is better described by first order kinetics; this peak is believed to correspond to the long-range migration of the self-interstitial, preferentially to impurities where they form clusters. It has been found that subthreshold irradiation results in the annealing of damage already present. This radiation annealing effect may be a contributing factor to the seesaw effect. Another physical process may contribute to the seesaw effect, namely, the trapping of interstitials at impurities and their subsequent detrapping during annealing

  11. 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

  12. Property change during nanosecond pulse laser annealing of ...

    Indian Academy of Sciences (India)

    Property change during nanosecond pulse laser annealing of amorphous. NiTi thin film ... near equiatomic Ni/Ti composition to produce partially crystallized highly sensitive R-phase spots surrounded by amorphous regions. Scanning ... ratio, shape recovery, damping capacity, chemical resistance, biocompatibility and ...

  13. Thermal annealing and ionic abrasion in ZnTe

    International Nuclear Information System (INIS)

    Bensahel, D.

    1975-01-01

    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 [fr

  14. Competitive annealing of multiple DNA origami: formation of chimeric origami

    International Nuclear Information System (INIS)

    Majikes, Jacob M; Nash, Jessica A; LaBean, Thomas H

    2016-01-01

    Scaffolded DNA origami are a robust tool for building discrete nanoscale objects at high yield. This strategy ensures, in the design process, that the desired nanostructure is the minimum free energy state for the designed set of DNA sequences. Despite aiming for the minimum free energy structure, the folding process which leads to that conformation is difficult to characterize, although it has been the subject of much research. In order to shed light on the molecular folding pathways, this study intentionally frustrates the folding process of these systems by simultaneously annealing the staple pools for multiple target or parent origami structures, forcing competition. A surprising result of these competitive, simultaneous anneals is the formation of chimeric DNA origami which inherit structural regions from both parent origami. By comparing the regions inherited from the parent origami, relative stability of substructures were compared. This allowed examination of the folding process with typical characterization techniques and materials. Anneal curves were then used as a means to rapidly generate a phase diagram of anticipated behavior as a function of staple excess and parent staple ratio. This initial study shows that competitive anneals provide an exciting way to create diverse new nanostructures and may be used to examine the relative stability of various structural motifs. (paper)

  15. Coalescence during annealing of quiescent immiscible polymer blends

    Czech Academy of Sciences Publication Activity Database

    Dimzoski, Bojan; Fortelný, Ivan; Šlouf, Miroslav; Nevoralová, Martina; Michálková, Danuše; Mikešová, Jana

    -, 011 (2011), s. 1-12 ISSN 1618-7229 R&D Projects: GA AV ČR IAA200500903 Institutional research plan: CEZ:AV0Z40500505 Keywords : coalescence * polymer blends * annealing Subject RIV: BJ - Thermodynamics Impact factor: 0.515, year: 2011 http://www.e-polymers.org/journal/papers/bdimzoski_010311.pdf

  16. The effect of humidity on annealing of polymer optical fibre bragg gratings

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Bang, Ole

    2015-01-01

    The effect of humidity on annealing of PMMA based microstructured polymer optical fiber (mPOF) Bragg gratings is studied. Polymer optical fibers (POFs) are annealed in order to release stress formed during the fabrication process. Un-annealed fibers will have high hysteresis and low sensitivity...... to humidity, particularly when operated at high temperature. Typically annealing of PMMA POFs is done at 80oC in an oven with no humidity control and therefor at low humidity. The response to humidity of PMMA FBGs annealed at different levels of humidity at the same temperature has also been studied. PMMA...... FBGs annealed at high humidity have response with no hysteresis and an improved sensitivity which are independent of temperature compared to FBGs annealed at the same temperature but at lower humidity. In addition, PMMA FBG annealed at high humidity showed a permanent blue shift more than 200nm, which...

  17. The effect of pre-annealing on the structural evolution and optical ...

    Indian Academy of Sciences (India)

    65

    Ag thin films of 5nm thickness were deposited on glass substrates by thermal evaporation. The films were divided into two sets out of which one set was not annealed and the other set was subjected to pre-annealing at 300oC for 2 hrs in air. The un-annealed and pre-annealed films were exposed to iodine vapours at room ...

  18. Optimized Laser Thermal Annealing on Germanium for High Dopant Activation and Low Leakage Current

    DEFF Research Database (Denmark)

    Shayesteh, Maryam; O' Connell, Dan; Gity, Farzan

    2014-01-01

    In this paper, state-of-the-art laser thermal annealing is used to fabricate Ge diodes. We compared the effect of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical properties of phosphorus and Arsenic-doped n +/p junctions. Using LTA, high carrier...

  19. Electro-optical characteristics of indium tin oxide (ITO) films: effect of thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.V.; Salehi, A.; Aliyu, Y.H.; Bunce, R.W. [University of Wales College of Cardiff (United Kingdom). School of Electrical, Electronics and System Engineering

    1996-02-01

    The effect of thermal annealing on the electrical and optical characteristics of ITO films prepared by reactive sputtering and thermal evaporation have been studied. The effect of the thermal annealing is to improve the conductivity and the optical transmission in the shorter wavelength region. The conductivity of the films increases with annealing temperature, this behaviour is associated with grain growth in the film. (author)

  20. Nitrogen aggregation in Ib type synthetic diamonds at low pressure and high-temperature annealing

    International Nuclear Information System (INIS)

    Kazyuchits, N.M.; Rusetskij, M.S.; Latushko, Ya.I.; Kazyuchits, V.N.; Zajtsev, A.M.

    2015-01-01

    A new technique for annealing of diamonds at low pressure and high temperature (LPHT) is considered. The absorption spectra of synthetic Ib diamonds are given before and after annealing. This is evident from a comparison of the spectra that nitrogen aggregation process takes place at the LPHT annealing diamond. (authors)

  1. 78 FR 31577 - Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan

    Science.gov (United States)

    2013-05-24

    ...)] Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan Determination On the basis of the... reason of imports from Japan of diffusion-annealed, nickel-plated flat-rolled steel products, provided... diffusion-annealed, nickel-plated flat-rolled steel products from Japan. Accordingly, effective March 27...

  2. Cyclical Annealing Technique To Enhance Reliability of Amorphous Metal Oxide Thin Film Transistors.

    Science.gov (United States)

    Chen, Hong-Chih; Chang, Ting-Chang; Lai, Wei-Chih; Chen, Guan-Fu; Chen, Bo-Wei; Hung, Yu-Ju; Chang, Kuo-Jui; Cheng, Kai-Chung; Huang, Chen-Shuo; Chen, Kuo-Kuang; Lu, Hsueh-Hsing; Lin, Yu-Hsin

    2018-02-26

    This study introduces a cyclical annealing technique that enhances the reliability of amorphous indium-gallium-zinc-oxide (a-IGZO) via-type structure thin film transistors (TFTs). By utilizing this treatment, negative gate-bias illumination stress (NBIS)-induced instabilities can be effectively alleviated. The cyclical annealing provides several cooling steps, which are exothermic processes that can form stronger ionic bonds. An additional advantage is that the total annealing time is much shorter than when using conventional long-term annealing. With the use of cyclical annealing, the reliability of the a-IGZO can be effectively optimized, and the shorter process time can increase fabrication efficiency.

  3. 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....

  4. Nickel silicide formation using multiple-pulsed laser annealing

    International Nuclear Information System (INIS)

    Setiawan, Y.; Lee, P. S.; Pey, K. L.; Wang, X. C.; Lim, G. C.; Chow, F. L.

    2007-01-01

    The effect of multiple-pulsed laser irradiation on Ni silicide formation in Ni(Ti)/Si system was studied. A layered structure consisting of both crystalline NiSi 2 and Ni-rich Ni-Si amorphous phases with a protective TiO x overlayer was formed after five-pulsed laser annealing at 0.4 J cm -2 . Different solidification velocities caused by a variation in the atomic concentration across the melt have led to the formation of this layered structure. On the other hand, by increasing the number of laser pulses, a continuous layer of polycrystalline NiSi was obtained after a 20-pulsed laser annealing at 0.3 J cm -2 laser fluence. Its formation is attributed to a better elemental mixing which occurred during subsequent pulses. Enhancement of surface absorption and remelting of the phases formed is proposed as the mechanism governing the continuous NiSi layer formation

  5. 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

  6. 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.

  7. Selection of views to materialize using simulated annealing algorithms

    Science.gov (United States)

    Zhou, Lijuan; Liu, Chi; Wang, Hongfeng; Liu, Daixin

    2002-03-01

    A data warehouse contains lots of materialized views over the data provided by the distributed heterogeneous databases for the purpose of efficiently implementing decision-support or OLAP queries. It is important to select the right view to materialize that answer a given set of queries. The goal is the minimization of the combination of the query evaluation and view maintenance costs. In this paper, we have addressed and designed algorithms for selecting a set of views to be materialized so that the sum of processing a set of queries and maintaining the materialized views is minimized. We develop an approach using simulated annealing algorithms to solve it. First, we explore simulated annealing algorithms to optimize the selection of materialized views. Then we use experiments to demonstrate our approach. The results show that our algorithm works better. We implemented our algorithms and a performance study of the algorithms shows that the proposed algorithm gives an optimal solution.

  8. Effect of annealing treatment on optical properties and ...

    Indian Academy of Sciences (India)

    68

    deposition method (PVD) by using of electron-beam evaporation at the vacuum chamber at 10-5. Torr. ... while silver deposited on the annealed WO3 layer at 300 °C. UV-visible spectrophotometer showed that the ... metals like Au and Cu at λ < 0.5 μm and at ≈ 0.8 μm for Ag [8], silver with both the lowest refractive index ...

  9. Reverse degradation of nickel graphene junction by hydrogen annealing

    Directory of Open Access Journals (Sweden)

    Zhenjun Zhang

    2016-02-01

    Full Text Available 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.

  10. Annealing behavior and selected applications of ion-implanted alloys

    International Nuclear Information System (INIS)

    Myers, S.M.

    Thermally activated processes cause ion-implanted metals to evolve from the initial state toward thermodynamic equilibrium. The degree of equilibration is strongly dependent upon temperature and is considered for three temperature regimes which are distinguished by the varying mobilities of interstitial and substitutional atoms. In addition, perturbations resulting from the irradiation environment are discussed. Examples are given of the use of implanted and annealed alloys in studies of diffusion, phase diagrams, and solute trapping

  11. Dating thermal events at Cerro Prieto using fission track annealing

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, S.J.; Elders, W..

    1981-01-01

    Data from laboratory experiments and geologic fading studies were compiled from published sources to produce lines of iso-annealing for apatite in time-temperature space. Fission track ages were calculated for samples from two wells at Cerro Prieto, one with an apparently simple and one with an apparently complex thermal history. Temperatures were estimated by empirical vitrinite reflectance geothermometry, fluid inclusion homogenization and oxygen isotope equilibrium. These estimates were compared with logs of measured borehole temperatures.

  12. 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...... for the samples with the highest degree of phosphorylation. The phosphate level remained almost unaffected during the entire process. Therefore, the effects observed are not caused by hydrolysis of the phosphate esters, bur rather by their reorientation toward positions causing less interference of molecular...

  13. Infrared reflectiity and transmissivity of boron implanted, laser annealed silicon

    International Nuclear Information System (INIS)

    Engstrom, H.

    1979-01-01

    The mid-infrared reflectance and transmittance of boron implanted, laser annealed silicon was measured. A Drude model of free holes was used to obtain the dielectric constant of the implanted layer. A least squares adjustment of (1) the ratio of boron concentration to effective hole mass; and (2) the relaxation time gave a fairly good fit to the data and permitted determination of these parameters

  14. Magnetic annealing of plated high saturation magnetization soft magnetic FeCo alloy films

    International Nuclear Information System (INIS)

    Sun, N.X.; Mehdizadeh, S.; Bonhote, C.; Xiao, Q.F.; York, B.

    2005-01-01

    Plated high saturation magnetization soft magnetic FeCo films were annealed in magnetic field; their stress, microstructure, and magnetic properties were investigated. The FeCo films consistently showed a reduced tensile stress after magnetic annealing at temperatures above 255 deg. C. The annealing temperature was found to be the primary factor in reducing the tensile stress, while annealing time was secondary. The FeCo films showed improved soft magnetic properties when subjected to an easy axis annealing with reduced coercivities along both the easy axis and hard axis. Hard axis annealing on these FeCo films caused a switched easy and hard axis in these films when the annealing temperature is above 255 deg. C

  15. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2005-11-21

    A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops.

  16. Effect of post annealing temperatures on microstructures and mechanical properties of cryorolled 5052 aluminium sheet alloy

    Science.gov (United States)

    Anas, N. M.; Umar, Z. A. A.; Zuhailawati, H.; Anasyida, A. S.

    2017-07-01

    The effect of post annealing temperature of cryorolled 5052 Al alloy after cryorolling process at 30% thickness reduction was investigated, focusing on the evolution of microstructures and mechanical properties. The evolution of microstructure was investigated using optical microscopy (OM). The mechanical behaviour of the samples have been evaluated through Vickers hardness and tensile test performed at room temperature. The results showed that the post annealing on cryorolled 5052 Al alloy have enhanced the ductility with sacrificing the hardness and strength. The lattice strain of post annealed 5052 Al alloy decreased with increasing of annealing temperatures. The evolution of microstructure of the post annealed 5052 Al alloy showed equiaxed grains at 200°C and grain coarsening as post annealing temperature increases to 350°C. The result of crystallite size confirmed the grain size increased as the post annealing temperature rises.

  17. 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.

  18. Nuclear techniques of analysis in diamond synthesis and annealing

    International Nuclear Information System (INIS)

    Jamieson, D. N.; Prawer, S.; Gonon, P.; Walker, R.; Dooley, S.; Bettiol, A.; Pearce, J.

    1996-01-01

    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

  19. 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.

  20. Chromium depletion from stainless steels during vacuum annealing

    International Nuclear Information System (INIS)

    Smith, A.F.; Hales, R.

    1977-01-01

    During selective chromium oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1,000 0 C, has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within approximately 2μm of the surface where the chromium concentration decreased more steeply than expected. (orig.) [de

  1. Regrowth zones in laser annealed radiation damaged diamond

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Prawer, S.; Dooley, S.P.; Kalish, R.; Technion-Israel Inst. of Tech., Haifa

    1993-01-01

    Focused laser annealing of ion implanted diamond with a 15 μm diameter laser spot produces as variety of effects that depend on the power density of the laser. Channeling Contrast Microscopy (CCM) provides a relatively straight forward, rapid, method to analyse the annealed regions of the diamond to characterize the effects. In order of increasing laser power density, effects that are observed include: regrowth of the end of range damage of the ion implantation, formation of a buried graphitic layer and complete graphitization of the surface of the diamond down to the bottom of the original damage layer. Information provided by CCM leads to an understanding the causes of these effects and provides insight into the carbon phase diagram in the neighbourhood of the graphite to diamond phase transition. Analysis of the effects of laser annealing by CCM are complicated by the swelling of the diamond lattice caused by the original ion implantation, compaction following regrowth and the effect of the analysis beam irradiation itself. 12 refs., 5 figs

  2. Damage and in-situ annealing during ion implantation

    International Nuclear Information System (INIS)

    Sadana, D.K.; Washburn, J.; Byrne, P.F.; Cheung, N.W.

    1982-11-01

    Formation of amorphous (α) layers in Si during ion implantation in the energy range 100 keV-11 MeV and temperature range liquid nitrogen (LN)-100 0 C has been investigated. Cross-sectional transmission electron microscopy (XTEM) shows that buried amorphous layers can be created for both room temperature (RT) and LN temperature implants, with a wider 100 percent amorphous region for the LN cooled case. The relative narrowing of the α layer during RT implantation is attributed to in-situ annealing. Implantation to the same fluence at temperatures above 100 0 C does not produce α layers. To further investigate in situ annealing effects, specimens already containing buried α layers were further irradiated with ion beams in the temperature range RT-400 0 C. It was found that isolated small α zones (less than or equal to 50 diameter) embedded in the crystalline matrix near the two α/c interfaces dissolved into the crystal but the thickness of the 100 percent α layer was not appreciably affected by further implantation at 200 0 C. A model for in situ annealing during implantation is presented

  3. Microstructural evolution of nanostructure 7075 aluminum alloy during isothermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Yazdian, N. [Department of Materials Engineering, Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Karimzadeh, F., E-mail: karimzadeh_f@cc.iut.ac.i [Department of Materials Engineering, Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Tavoosi, M. [Department of Materials Engineering, Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2010-03-18

    This work focuses on structural changes of nanostructure 7075 aluminum alloy (Al7075) during isothermal annealing. Nanostructured Al7075 was synthesized by mechanical alloying. The produced structure was isothermally heat-treated at 125-500 {sup o}C for 1-3 h under argon atmosphere. The as-milled and annealed powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that after 15 h of milling, an Al-Zn-Mg-Cu supersaturated solid solution with a grain size of 35 nm was obtained. By increasing the milling time up to 15 h, the MgZn phase precipitated from supersaturated solid solution. Large variety of precipitants including MgZn, MgZn{sub 2} (at temperatures range between 200 and 400 {sup o}C), AlCuMg and Al{sub 2}Cu (at temperatures range between 300 and 500 {sup o}C) were formed during isothermal annealing.

  4. Quantification of annealed microstructures in ARB processed aluminum

    International Nuclear Information System (INIS)

    Kamikawa, Naoya; Tsuji, Nobuhiro; Huang, Xiaoxu; Hansen, Niels

    2006-01-01

    High-purity aluminum (99.99% purity) deformed by accumulative roll bonding to an equivalent strain of 4.8 has been characterized by transmission electron microscopy and electron backscatter diffraction techniques in the deformed state and after various annealing treatments. These two techniques are compared and discussed. The majority of the structure in the as-deformed state is composed of equiaxed crystallites surrounded mostly by high-angle boundaries with misorientation angle above 15 o . However, regions that contain a high concentration of low-angle boundaries with misorientation angle below 15 o in a lamellar structure elongated along the rolling direction have also been observed. The microstructure is correlated with the local texture as the equiaxed structure contains a mixture of texture components whereas the lamellar structure has orientations corresponding to rolling or shear texture components. Annealing of deformed specimens causes structural coarsening without removing the regions with a high concentration of low-angle boundaries. Heat treatment for a short period of time (0.5 h) leads to the start of recrystallization at 200 deg. C, whereas a heat treatment at 175 deg. C for an extended period (6 h) allows heat treatments to be carried out at temperatures above 200 deg. C without initiation of recrystallization. The two-step process is a promising route for producing almost uniform equiaxed structures by annealing of samples that have been deformed to large strains

  5. 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.

  6. The annealing helicase and branch migration activities of Drosophila HARP.

    Directory of Open Access Journals (Sweden)

    George A Kassavetis

    Full Text Available HARP (SMARCAL1, MARCAL1 is an annealing helicase that functions in the repair and restart of damaged DNA replication forks through its DNA branch migration and replication fork regression activities. HARP is conserved among metazoans. HARP from invertebrates differs by the absence of one of the two HARP-specific domain repeats found in vertebrates. The annealing helicase and branch migration activity of invertebrate HARP has not been documented. We found that HARP from Drosophila melanogaster retains the annealing helicase activity of human HARP, the ability to disrupt D-loops and to branch migrate Holliday junctions, but fails to regress model DNA replication fork structures. A comparison of human and Drosophila HARP on additional substrates revealed that both HARPs are competent in branch migrating a bidirectional replication bubble composed of either DNA:DNA or RNA:DNA hybrid. Human, but not Drosophila, HARP is also capable of regressing a replication fork structure containing a highly stable poly rG:dC hybrid. Persistent RNA:DNA hybrids in vivo can lead to replication fork arrest and genome instability. The ability of HARP to strand transfer hybrids may signify a hybrid removal function for this enzyme, in vivo.

  7. Metode Simulated Annealing untuk Optimasi Penjadwalan Perkuliahan Perguruan Tinggi

    Directory of Open Access Journals (Sweden)

    Wiktasari Sari

    2016-12-01

    Full Text Available Course scheduling an assignment of courses and lecturers in the available time slots involving certain restrictions. Simulated annealing is a heuristic method can be used as search method and provide acceptable solutions with good results. The research aims to make scheduling courses at the college using simulated annealing using five variables data that lecturer courses, the time slot is comprised of the day and the time period and class room. The research has two objective functions to be generated, the first is the assignment of a lecturer on courses that will be of teaching, second lecturers and their assignment course on the time slot and the room available. The objective function is calculated by taking into account the restrictions involved to produce the optimal solution. The validation is performed by testing to simulated annealing method with an varian average of 77.791% of the data variance can reach a solution with a standard deviation of 3.931509. In this research given the method of solution in the use of the remaining search space to be reused by the data that is unallocated.

  8. 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

  9. Improvement on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors using post deposition annealing and post metallization annealing

    Energy Technology Data Exchange (ETDEWEB)

    Esakky, Papanasam, E-mail: papanasamte@gmail.com; Kailath, Binsu J

    2017-08-15

    Highlights: • Post deposition annealing (PDA) and post metallization annealing (PMA) on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors. • Post deposition N{sub 2}O plasma annealing inhibits crystallization of HfO{sub 2} during high temperature annealing. • Plasma annealing followed by RTA in N{sub 2} results in formation of hafnium silicate at the HfO{sub 2}-SiC interface. • PDA reduces interface state density (D{sub it}) and gate leakage current density (J{sub g}) by order. • PMA in forming gas for 40 min results in better passivation and reduces D{sub it} by two orders and J{sub g} by thrice. - Abstract: HfO{sub 2} as a gate dielectric enables high electric field operation of SiC MIS structure and as gas sensor HfO{sub 2}/SiC capacitors offer higher sensitivity than SiO{sub 2}/SiC capacitors. The issue of higher density of oxygen vacancies and associated higher leakage current necessitates better passivation of HfO{sub 2}/SiC interface. Effect of post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas on the structural and electrical characteristics of Pd/HfO{sub 2}/SiC MIS capacitors are reported in this work. N{sub 2}O plasma annealing suppresses crystallization during high temperature annealing thereby improving the thermal stability and plasma annealing followed by rapid thermal annealing in N{sub 2} result in formation of Hf silicate at the HfO{sub 2}/SiC interface resulting in order of magnitude lower density of interface states and gate leakage current. Post metallization annealing in forming gas for 40 min reduces interface state density by two orders while gate leakage current density is reduced by thrice. Post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas are observed to be effective passivation techniques improving the electrical characteristics of HfO{sub 2}/SiC capacitors.

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

    International Nuclear Information System (INIS)

    Spencer, Gregory; Anyamesem-Mensah, Benedict; Galloway, Heather C.; Bandyopadhyay, Anup; Frasier, Daniel

    2011-01-01

    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.

  11. Ising formulation of associative memory models and quantum annealing recall

    Science.gov (United States)

    Santra, Siddhartha; Shehab, Omar; Balu, Radhakrishnan

    2017-12-01

    Associative memory models, in theoretical neuro- and computer sciences, can generally store at most a linear number of memories. Recalling memories in these models can be understood as retrieval of the energy minimizing configuration of classical Ising spins, closest in Hamming distance to an imperfect input memory, where the energy landscape is determined by the set of stored memories. We present an Ising formulation for associative memory models and consider the problem of memory recall using quantum annealing. We show that allowing for input-dependent energy landscapes allows storage of up to an exponential number of memories (in terms of the number of neurons). Further, we show how quantum annealing may naturally be used for recall tasks in such input-dependent energy landscapes, although the recall time may increase with the number of stored memories. Theoretically, we obtain the radius of attractor basins R (N ) and the capacity C (N ) of such a scheme and their tradeoffs. Our calculations establish that for randomly chosen memories the capacity of our model using the Hebbian learning rule as a function of problem size can be expressed as C (N ) =O (eC1N) , C1≥0 , and succeeds on randomly chosen memory sets with a probability of (1 -e-C2N) , C2≥0 with C1+C2=(0.5-f ) 2/(1 -f ) , where f =R (N )/N , 0 ≤f ≤0.5 , is the radius of attraction in terms of the Hamming distance of an input probe from a stored memory as a fraction of the problem size. We demonstrate the application of this scheme on a programmable quantum annealing device, the D-wave processor.

  12. Simulated annealing band selection approach for hyperspectral imagery

    Science.gov (United States)

    Chang, Yang-Lang; Fang, Jyh-Perng; Hsu, Wei-Lieh; Chang, Lena; Chang, Wen-Yen

    2010-09-01

    In hyperspectral imagery, greedy modular eigenspace (GME) was developed by clustering highly correlated bands into a smaller subset based on the greedy algorithm. Unfortunately, GME is hard to find the optimal set by greedy scheme except by exhaustive iteration. The long execution time has been the major drawback in practice. Accordingly, finding the optimal (or near-optimal) solution is very expensive. Instead of adopting the band-subset-selection paradigm underlying this approach, we introduce a simulated annealing band selection (SABS) approach, which takes sets of non-correlated bands for high-dimensional remote sensing images based on a heuristic optimization algorithm, to overcome this disadvantage. It utilizes the inherent separability of different classes embedded in high-dimensional data sets to reduce dimensionality and formulate the optimal or near-optimal GME feature. Our proposed SABS scheme has a number of merits. Unlike traditional principal component analysis, it avoids the bias problems that arise from transforming the information into linear combinations of bands. SABS can not only speed up the procedure to simultaneously select the most significant features according to the simulated annealing optimization scheme to find GME sets, but also further extend the convergence abilities in the solution space based on simulated annealing method to reach the global optimal or near-optimal solution and escape from local minima. The effectiveness of the proposed SABS is evaluated by NASA MODIS/ASTER (MASTER) airborne simulator data sets and airborne synthetic aperture radar images for land cover classification during the Pacrim II campaign. The performance of our proposed SABS is validated by supervised k-nearest neighbor classifier. The experimental results show that SABS is an effective technique of band subset selection and can be used as an alternative to the existing dimensionality reduction method.

  13. 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.

  14. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P.; McCallum, J.C. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  15. Irradiation-induced swelling in solution annealed AISI 316

    International Nuclear Information System (INIS)

    Bates, J.F.; Weiner, R.A.; Korenko, M.K.

    1978-11-01

    Swelling in solution annealed AISI 316 has been empirically described as a function of temperature and fluence. An equation, suitable for design purposes, has been developed from an analysis of all of the available swelling data and complementary investigations. The equation is bi-linear in nature and incorporates different temperature dependent functions for both the maximum linear swelling rate parameter and the incubation parameter. The equation describing the swelling rate parameter differs from previous functions in that a constant swelling rate occurs from around 450 to 500 0 C followed by a peak swelling rate at around 570 0 C

  16. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Beirau, Tobias; Mihailova, Boriana; Groat, Lee A.; Chudy, Thomas; Shelyug, Anna; Navrotsky, Alexandra; Ewing, Rodney C.; Schlüter, Jochen; Škoda, Radek; Bismayer, Ulrich

    2017-01-01

    Abstract

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

  17. Annealed Demon Algorithms Solving the Environmental / Economic Dispatch Problem

    Directory of Open Access Journals (Sweden)

    Aristidis VLACHOS

    2013-06-01

    Full Text Available This paper presents an efficient and reliable Annealed Demon (AD algorithm for the Environmental/Economic Dispatch (EEB problem. The EED problem is a multi-objective non-linear optimization problem with constraints. This problem is one of the fundamentals issues in power system operation. The system of generation associates thermal generators and emissions which involves sulphur oxides (SO2 and nitrogen oxides (NOx. The aim is to minimize total fuel cost of the system and control emission. The proposed AD algorithm is applied for EED of a simple power system.

  18. Development and anneal of radiation damage in salt

    International Nuclear Information System (INIS)

    Garcia Celma, A.; Donker, H.; Soppe, W.J.; Miralles, L.

    1993-12-01

    Laboratory gamma-irradiations at a constant temperature (100 C) were carried out in two sorts of experiments, one at variable and another at approximately constant dose rates. The damage developed during irradiation was analyzed by thermal analysis, microstructural analysis and small angle neutron scattering. The results were compared with the yields of the Jain-Lidiard model for each experiment. Experiments at a constant dose rate were planned to obtain information on radiation damage development and anneal in conditions as near as possible to those of radioactive waste repository concepts. For this reason the dose rates were kept low. (orig./DG)

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

    International Nuclear Information System (INIS)

    Narayan, J.

    1979-01-01

    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 10 80 C/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

  20. Testing of irradiated and annealed 15H2MFA materials

    International Nuclear Information System (INIS)

    Gillemot, F.; Uri, G.

    1994-01-01

    A set of surveillance samples made from 15H2MFA material has been studied in the laboratory of AEKI. Miniature notched tensile specimens were cut from some remnants of irradiated and broke surveillance charpy remnants. The Absorbed Specific Fracture Energy (ASFE) was measured on the specimens. A cutting machine and testing technique were elaborated for the measurements. The second part of the Charpy remnants was annealed at 460 deg. C and 490 deg. C for 6-8 hours. The specimens were tested similarity and the results were compared. (author). 5 refs, 9 figs

  1. Combined Simulated Annealing Algorithm for the Discrete Facility Location Problem

    Directory of Open Access Journals (Sweden)

    Jin Qin

    2012-01-01

    Full Text Available The combined simulated annealing (CSA algorithm was developed for the discrete facility location problem (DFLP in the paper. The method is a two-layer algorithm, in which the external subalgorithm optimizes the decision of the facility location decision while the internal subalgorithm optimizes the decision of the allocation of customer's demand under the determined location decision. The performance of the CSA is tested by 30 instances with different sizes. The computational results show that CSA works much better than the previous algorithm on DFLP and offers a new reasonable alternative solution method to it.

  2. Optimisation of electron beam characteristics by simulated annealing

    International Nuclear Information System (INIS)

    Ebert, M.A.; University of Adelaide, SA; Hoban, P.W.

    1996-01-01

    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 - 2x10 4 ) 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

  3. Effect of thermal annealing on properties of polycrystalline ZnO thin films

    Science.gov (United States)

    Gritsenko, L. V.; Abdullin, Kh. A.; Gabdullin, M. T.; Kalkozova, Zh. K.; Kumekov, S. E.; Mukash, Zh. O.; Sazonov, A. Yu.; Terukov, E. I.

    2017-01-01

    Electrical properties (density, carriers mobility, resistivity), optical absorption and photoluminescence spectra of ZnO, grown by MOCVD and hydrothermal methods, have been investigated depending on the annealing and treatment modes in a hydrogen plasma. It has been shown that the electrical and photoluminescent (PL) properties of ZnO are strongly dependent on gas atmosphere during annealing. The annealing in oxygen atmosphere causes a sharp drop of carrier mobility and films conductivity due to the absorption of oxygen on grain boundaries. The process of ZnO electrical properties recovery by the thermal annealing in inert atmosphere (nitrogen), in oil (2×10-2 mbar) and oil-free (1×10-5 mbar) vacuum has been investigated. The hydrogen plasma treatment influence on the intensity of near-band-gap emission (NBE) has been studied. The effect of annealing and subsequent plasma treatment on PL intensity depends on the gas atmosphere of preliminary thermal annealing.

  4. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    CERN Document Server

    Rhee, J Y

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder -> order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by p...

  5. Effects of Annealing on TiN Thin Film Growth by DC Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Azadeh Jafari

    2014-07-01

    Full Text Available We have reviewed the deposition of titanium nitride (TiN thin films on stainless steel substrates by a DC magnetron sputtering method and annealing at different annealing temperatures of 500, 600, and 700°C for 120 min in nitrogen/argon atmospheres. Effects of annealing temperatures on the structural and the optical properties of TiN films were investigated using X-ray diffraction (XRD, atomic force microscope (AFM, field emission scanning electron microscopy (FESEM, and UV-VIS spectrophotometer. Our experimental studies reveal that the annealing temperature appreciably affected the structures, crystallite sizes, and reflection of the films. By increasing the annealing temperature to 700°C crystallinity and reflection of the film increase. These results suggest that annealed TiN films can be good candidate for tokamak first wall due to their structural and optical properties.

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

    International Nuclear Information System (INIS)

    Emoto, T.; Akimoto, K.; Yoshida, Y.; Ichimiya, A.; Nabatame, T.; Toriumi, A.

    2005-01-01

    We studied the effect of post-deposition annealing on a HfO 2 /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/cm 3 grows at the interface between the HfO 2 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 HfO 2 layer

  7. Residual charges effect on the annealing behavior of Co-60 irradiated MOS capacitors

    International Nuclear Information System (INIS)

    Hwu, J.G.; Lee, G.S.; Lee, S.C.; Wang, W.S.

    1988-01-01

    It was experimentally observed that the residual charges of a MOS capacitor after C-V testing can exist for a long time. These residual charges induce a nonzero field at the SiO/sub 2//Si interface, and subsequently affect the annealing behavior due to a charge-temperature effect if the MOS capacitor is left floating during annealing. This problem is solved by a flat-band condition annealing method based on a charge-temperature technique. The annealing kinetics of a Co-60 irradiated MOS capacitor are then studied. A power law behavior of the annealing kinetics has been obtained for oxide charges annealed at 300 0 C. Possible explanations are given for this observation

  8. FTIR and Raman spectra of ion irradiated and annealed 4H-SiC

    International Nuclear Information System (INIS)

    Zhou Lihong; Yang Titao; Yao Cunfeng; Chinese Academy of Sciences, Beijing

    2007-01-01

    The 4H-SiC specimens were implanted with 110keV C-ions and then irradiated with 230MeV Pb-ions and subsequently annealed at different temperatures in vacuum. The samples were investigated after each annealing stage by using FTIR and Raman spectroscopy. The obtained FTIR spectra showed several interference fringes in the range from 960 cm -1 to 1450 cm -1 . The intensity of fringes decreases with the increase of annealing temperature, and an abrupt decrease of the fringe intensity was found for annealing above 900 degree C, indicating that there was a significant recovery of the irradiation-induced damage in the crystal for annealing at high temperatures. The Raman spectroscopy showed that after annealing at 1200 degree C for 30 min the amorphous layer was recovered and the precipitation of carbon atoms in graphite occurred. (authors)

  9. Unusual hardening behaviour in heavily cryo-rolled Cu-Al-Zn alloys during annealing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y.L. [Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China); Ren, S.Y. [Ningbo Powerway Alloy Material Co., Ltd, Ningbo 315135 (China); Zeng, S.D. [Yunnan Institute of Measuring and Testing Technology, Kunming 650228 (China); Zhu, X.K., E-mail: xk_zhu@hotmail.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China)

    2016-04-06

    Three nanostructured Cu-Al-Zn alloys were produced via rolling at the liquid nitrogen temperature. The deformed Cu alloys were then annealed at 150–300 °C for 1 h. The two alloys with high solute content and thus with low stacking fault energy exhibit unusual annealing hardening, namely, an increase in hardness and strength and a decrease in tensile elongation after annealing at 150 and 200 °C. From X-ray diffraction (XRD) analysis and microstructural observations by transmission electron microscopy (TEM), it is found that microstrain and dislocation density decrease after annealing at 200 °C because of the recovery of dislocations and the lattice parameter decreases due to solute segregation. Meanwhile, the twin density of the two Cu alloys increases and grain size remains basically unchanged. It is shown that the formation of annealing twins and stacking faults and the segregation of solute atoms may be the main causes of unusual annealing hardening.

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

    Energy Technology Data Exchange (ETDEWEB)

    Emoto, T. [Toyota National College of Technology, 2-1 Eisei-cho, Toyota, Aichi 471-8525 (Japan)]. E-mail: emoto@toyota-ct.ac.jp; Akimoto, K. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Yoshida, Y. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ichimiya, A. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Nabatame, T. [MIRAI-ASET, AIST Tsukuba West, Tsukuba, Ibaraki 305-8569 (Japan); Toriumi, A. [MIRAI-ASRC, AIST Tsukuba Central 4, Tsukuba, Ibaraki 305-8562 (Japan); University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2005-05-15

    We studied the effect of post-deposition annealing on a HfO{sub 2}/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/cm{sup 3} grows at the interface between the HfO{sub 2} 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 HfO{sub 2} layer.

  11. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Science.gov (United States)

    Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

    2015-08-01

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 1026 m-2) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min-1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

  12. Tailoring the magnetic properties and magnetorheological behavior of spinel nanocrystalline cobalt ferrite by varying annealing temperature

    OpenAIRE

    Sedlačík, Michal; Pavlínek, Vladimír; Peer, Petra; Filip, Petr

    2014-01-01

    Magnetic nanoparticles of spinel nanocrystalline cobalt ferrite were synthesized via the sol-gel method and subsequent annealing. The influence of the annealing temperature on the structure, magnetic properties, and magnetorheological effect was investigated. The finite crystallite size of the particles, determined by X-ray diffraction and the particle size observed via transmission electron microscopy, increased with the annealing temperature. The magnetic properties observed via a vibrating...

  13. Laser-annealed GaP OHMIC contacts for high-temperature devices

    International Nuclear Information System (INIS)

    Eknoyan, O.; Van der Hoeven, W.; Richardson, T.; Porter, W.A.; Coquat, J.A.

    1980-01-01

    The results of successful Nd:YAG laser annealed ohmic contacts on n-type GaP are reported. Comparisons on identical laser and thermal annealed contacts on the same substrates are performed. Aging investigations are also studied. The results indicate that laser annealed contacts have far superior electrical characteristics, much better surface morphology and are substantially more stable with aging than the same but thermally alloyed ones

  14. Low-temperature annealing of radiation defects in electron-irradiated gallium phosphide

    International Nuclear Information System (INIS)

    Kolb, A.A.; Megela, I.G.; Buturlakin, A.P.; Goyer, D.B.

    1990-01-01

    The isochronal annealing of radiation defects in high-energy electron irradiated n-GaP monocrystals within the 77 to 300 K range has been investigated by optical and electrical techniques. The changes in conductance and charge carrier mobility as functions of annealing temperature as well as the variation of optical absorption spectra of GaP under irradiation and annealing provide evidence that most of radiation defects are likely secondary complexes of defects

  15. Exponential Speedup of Quantum Annealing by Inhomogeneous Driving of the Transverse Field

    Science.gov (United States)

    Susa, Yuki; Yamashiro, Yu; Yamamoto, Masayuki; Nishimori, Hidetoshi

    2018-02-01

    We show, for quantum annealing, that a certain type of inhomogeneous driving of the transverse field erases first-order quantum phase transitions in the p-body interacting mean-field-type model with and without longitudinal random field. Since a first-order phase transition poses a serious difficulty for quantum annealing (adiabatic quantum computing) due to the exponentially small energy gap, the removal of first-order transitions means an exponential speedup of the annealing process. The present method may serve as a simple protocol for the performance enhancement of quantum annealing, complementary to non-stoquastic Hamiltonians.

  16. Annealing hardening in detwinning deformation of Mg–3Al–1Zn alloy

    International Nuclear Information System (INIS)

    Xin, Yunchang; Zhou, Xiaojun; Chen, Houwen; Nie, Jian-Feng; Zhang, Hong; Zhang, Yuanyuan; Liu, Qing

    2014-01-01

    The present work reports the effect of annealing treatment on detwinning deformation in Mg alloy AZ31 and pure Mg that have pre-strained twins. It shows that appropriate annealing enhances, rather than reduces, the yield strength of the pre-strained AZ31, but it does not cause any strengthening of the pre-strained pure Mg. STEM–EDS mapping shows that both Al and Zn segregate to twin boundaries in the pre-strained AZ31 after the annealing process. It is proposed that it is the pinning of twin boundary by segregated solute atoms that results in an increased activation stress for detwinning deformation and, hence, annealing hardening

  17. Behavior of oxygen in zinc oxide films through thermal annealing and its effect on sheet resistance

    International Nuclear Information System (INIS)

    Hiramatsu, Takahiro; Furuta, Mamoru; Matsuda, Tokiyoshi; Li, Chaoyang; Hirao, Takashi

    2011-01-01

    Behavior of oxygen in sputtering deposited ZnO films through thermal annealing and its effect on sheet resistance of the films were investigated. The crystallinities of the ZnO film were improved by post-deposition annealing in vacuum. However, the sheet resistance of ZnO film was dramatically decreased after post-deposition annealing in vacuum at more than 300 deg. C, while O 2 desorbed from the film. The oxygen vacancies which acted as donors were formed by the thermal annealing in vacuum. The sheet resistance of the films was recovered by annealing in oxygen ambient. In this paper, 18 O 2 gas as an oxygen isotope was used as the annealing ambient in order to distinguish from 16 O, which was constituent atom of the ZnO films. SIMS analysis revealed that 18 O diffused into the ZnO film from the top surface by 18 O 2 annealing. Therefore oxygen vacancies formed by the post-deposition annealing in vacuum could be compensated by the annealing in oxygen ambient.

  18. One accelerated method for predicting thermal annealing effects in post-irradiation CMOS devices

    International Nuclear Information System (INIS)

    He Baoping; Zhou Heqin; Guo Hongxia; Luo Yinhong; Zhang Fengqi; Yao Zhibin

    2005-01-01

    A method for accelerated predictions of the long-term anneal effects was presented. In order to find the correspondence between two anneals time, our estimating conditions were that each isochronal step was equal to the duration of the isothermal anneal leading to the same level of charge detrapping. The long term isothermal behavior at 100 degree C and 24 degree C of the type CC4007 CMOS devices were predicted by using isochronal anneal data of 25-250 degree C and compared with an experimental isothermal. The authors note a good agreement between simulation and experiment. (authors)

  19. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...... annealing or etching process. The annealing and etching processes have been tried in different sequence in order to investigate their impact on the sensor's performance. Results show with high confidence that fibre annealing can improve both strain and stress sensitivities. The fibre etching can also...

  20. Modeling of irradiation embrittlement and annealing/recovery in pressure vessel steels

    International Nuclear Information System (INIS)

    Lott, R.G.; Freyer, P.D.

    1996-01-01

    The results of reactor pressure vessel (RPV) annealing studies are interpreted in light of the current understanding of radiation embrittlement phenomena in RPV steels. An extensive RPV irradiation embrittlement and annealing database has been compiled and the data reveal that the majority of annealing studies completed to date have employed test reactor irradiated weldments. Although test reactor and power reactor irradiations result in similar embrittlement trends, subtle differences between these two damage states can become important in the interpretation of annealing results. Microstructural studies of irradiated steels suggest that there are several different irradiation-induced microstructural features that contribute to embrittlement. The amount of annealing recovery and the post-anneal re-embrittlement behavior of a steel are determined by the annealing response of these microstructural defects. The active embrittlement mechanisms are determined largely by the irradiation temperature and the material composition. Interpretation and thorough understanding of annealing results require a model that considers the underlying physical mechanisms of embrittlement. This paper presents a framework for the construction of a physically based mechanistic model of irradiation embrittlement and annealing behavior

  1. Evaluation of trapping parameters of annealed natural quartz

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rui [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Shisanling Seismic Station, Institute of Earthquake Science, CEA, 102200 Beijing (China); Wei, Ming-Jian, E-mail: weimj@cnu.edu.cn [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Song, Bo [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Beijing Jing Yuan School, 100040 Beijing (China); Zhang, Yan [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); School of TaiPingqiao, Nan Lu of West Railway Station, 100073 Beijing (China); Zhao, Qiu-Yue [Key Laboratory of Tourism and Resources Environment in Universities of Shandong, Taishan University, 271000 Tai’an (China); Pan, Bao-Lin; Li, Teng-Fei [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China)

    2016-05-15

    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 T{sub m} − T{sub stop} 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 kT{sub m}.

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

    Directory of Open Access Journals (Sweden)

    Shi-hua Zhan

    2016-01-01

    Full Text Available 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.

  3. Annealing of GaN under high pressure of nitrogen

    CERN Document Server

    Porowski, S; Kolesnikov, D; Lojkowski, W; Jager, V; Jäger, W; Bogdanov, V; Suski, T; Krukowski, S

    2002-01-01

    Gallium nitride, aluminum nitride and indium nitride are basic materials for blue optoelectronic devices. The essential part of the technology of these devices is annealing at high temperatures. Thermodynamic properties of the Ga-N system and their consequences to application of high nitrogen pressure for the annealing of GaN based materials are summarized. The diffusion of Zn, Mg and Au in high dislocation density heteroepitaxial GaN/Al sub 2 O sub 3 layers will be compared with the diffusion in dislocation-free GaN single crystals and homoepitaxial layers. It will be shown that high dislocation density can drastically change the diffusion rates, which strongly affects the performance of nitride devices. Inter-diffusion of Al, Ga and In in AlGaN/GaN and InGaN/GaN quantum well (QW) structures will be also considered. It will be shown that in contrast to stability of metal contacts, which is strongly influenced by dislocations, the inter-diffusion of group III atoms in QW structures is not affected strongly by...

  4. Evaluation of trapping parameters of annealed natural quartz

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 T m  − T stop 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 kT m .

  5. Coupled Qubits for Next Generation Quantum Annealing: Novel Interactions

    Science.gov (United States)

    Samach, Gabriel; Weber, Steven; Hover, David; Rosenberg, Danna; Yoder, Jonilyn; Kim, David; Oliver, William D.; Kerman, Andrew J.

    While the first generation of quantum annealers based on Josephson junction technology have been successfully engineered to represent arrays of spins in the quantum transverse-field Ising model, no circuit architecture to date has succeeded in emulating the more complicated non-stoquastic Hamiltonians of interest for next generation quantum annealing. Here, we present our recent results for tunable ZZ- and XX-coupling between high coherence superconducting flux qubits. We discuss the larger architectures these coupled two-qubit building blocks will enable, as well as comment on the limitations of such architectures. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

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

    International Nuclear Information System (INIS)

    Jaksic, A.B.; Pejovic, M.M.; Ristic, G.S.

    1999-01-01

    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

  7. Microplastic processes developed in pure Ag with mesoscale annealing twins

    Energy Technology Data Exchange (ETDEWEB)

    Al-Fadhalah, Khaled Jabr Hasan [Mechanical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait)], E-mail: fadhalah@kuc01.kuniv.edu.kw; Li, Chun-Ming [Alcan Rolled Products-Ravenswood, LLC. P.O. Box 68, Century Road, Ravenswood, WV 26164 (United States)], E-mail: chun-ming.li@alcan.com; Beaudoin, A.J. [Department of Mechanical Science and Engineering, University of Illinois, 1206 West Green Street, Urbana, IL 61801 (United States)], E-mail: abeaudoi@uiuc.edu; Korzekwa, D.A. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Robertson, I.M. [Department of Materials Science and Engineering, University of Illinois, 1304 W. Green Street, Urbana, IL 61801 (United States)], E-mail: ianr@uiuc.edu

    2008-11-15

    The impact of annealing twin boundaries with a high residual defect content on the mechanical response of polycrystalline fine- and coarse-grained (2 and 20 {mu}m) silver was investigated through transmission electron microscopy and modeling. Besides an increase in the yield strength, the fine-grained material exhibited an inflection in the stress-strain curve after initial yield. Static and dynamic TEM studies revealed that the annealing twin boundaries acted as sources of perfect dislocations, partial dislocations and deformation twins; as barriers to the propagation of these dislocations; and as annihilation sites for dislocations. With increasing strain and as the twin boundaries were penetrated by dislocations, they contributed less to the overall mechanical properties. Based on these observations, equations for the evolution of mobile and forest dislocation densities are posed, depicting boundary sources and dislocation-dislocation interactions, respectively. The deformation response is modeled by computing the aggregate response of matrix-twin composite grains in the viscoplastic self-consistent scheme, which permits consideration of compatibility and equilibrium requirements across the twin boundaries. This work highlights the significant role boundaries play in generating the dislocations that control the macroscopic mechanical response.

  8. Sparse approximation problem: how rapid simulated annealing succeeds and fails

    Science.gov (United States)

    Obuchi, Tomoyuki; Kabashima, Yoshiyuki

    2016-03-01

    Information processing techniques based on sparseness have been actively studied in several disciplines. Among them, a mathematical framework to approximately express a given dataset by a combination of a small number of basis vectors of an overcomplete basis is termed the sparse approximation. In this paper, we apply simulated annealing, a metaheuristic algorithm for general optimization problems, to sparse approximation in the situation where the given data have a planted sparse representation and noise is present. The result in the noiseless case shows that our simulated annealing works well in a reasonable parameter region: the planted solution is found fairly rapidly. This is true even in the case where a common relaxation of the sparse approximation problem, the G-relaxation, is ineffective. On the other hand, when the dimensionality of the data is close to the number of non-zero components, another metastable state emerges, and our algorithm fails to find the planted solution. This phenomenon is associated with a first-order phase transition. In the case of very strong noise, it is no longer meaningful to search for the planted solution. In this situation, our algorithm determines a solution with close-to-minimum distortion fairly quickly.

  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. Microplastic processes developed in pure Ag with mesoscale annealing twins

    International Nuclear Information System (INIS)

    Al-Fadhalah, Khaled Jabr Hasan; Li, Chun-Ming; Beaudoin, A.J.; Korzekwa, D.A.; Robertson, I.M.

    2008-01-01

    The impact of annealing twin boundaries with a high residual defect content on the mechanical response of polycrystalline fine- and coarse-grained (2 and 20 μm) silver was investigated through transmission electron microscopy and modeling. Besides an increase in the yield strength, the fine-grained material exhibited an inflection in the stress-strain curve after initial yield. Static and dynamic TEM studies revealed that the annealing twin boundaries acted as sources of perfect dislocations, partial dislocations and deformation twins; as barriers to the propagation of these dislocations; and as annihilation sites for dislocations. With increasing strain and as the twin boundaries were penetrated by dislocations, they contributed less to the overall mechanical properties. Based on these observations, equations for the evolution of mobile and forest dislocation densities are posed, depicting boundary sources and dislocation-dislocation interactions, respectively. The deformation response is modeled by computing the aggregate response of matrix-twin composite grains in the viscoplastic self-consistent scheme, which permits consideration of compatibility and equilibrium requirements across the twin boundaries. This work highlights the significant role boundaries play in generating the dislocations that control the macroscopic mechanical response

  11. Annealing of defects in indium antimonide after ion bombardment

    International Nuclear Information System (INIS)

    Bogatyrev, V.A.; Kachurin, G.A.

    1977-01-01

    Indium antimonide electric properties are investigated after ion bombardment of different mass (with energy of 60 and 300 keV) and isochrone annealing in the 20-450 deg C temperature range. It is shown that 100-150 deg C n- type stable layers are formed after proton irradiation at room temperature only. Indium antimonide exposure by average mass ions under the same conditions and also by helium ions of 300 keV energy brings to p-type layer formation with high hole concentration. Subsequent heating at the temperature over 150 deg C results in electron conductivity of irradiated layers. Electron volume density and mobility efficiency reaches 10 18 cm -3 and 10 4 cm 2 /Vs respectively. N-type formed layers are stable up to 350 deg C allowing its usage for n-p transition formation admitting thermal treatment. Analysis is given of defect behaviour peculiarities depending upon the irradiation and annealing conditions. Hole conductivity in irradiated indium antimonide is supposed to be stipulated by regions of disorder, while electron conductivity - by relatively simpler disorders

  12. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, E., E-mail: dr.ersinyucel@gmail.com [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey); Kahraman, S. [Department of Metallurgy and Material Engineering, Faculty of Technology, Mustafa Kemal University, 31034 Hatay (Turkey); Güder, H.S. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey)

    2015-08-15

    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.

  13. Fracture behaviors of isotactic polypropylene/poly(ethylene oxide) blends: Effect of annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wu Haiyan; Li Xiaoxi; Wang Yonghong; Wu Jun; Huang Ting [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang Yong, E-mail: yongwang1976@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2011-10-15

    Highlights: {yields} Immiscible polypropylene/poly(ethylene oxide) was annealed at different temperatures (50-160 deg. C) for 12 h and at 100 deg. C for different durations (12-96 h). {yields} Fracture behaviors of the annealed samples were systematically investigated by means of various measurements. {yields} In a range of annealing temperature (100-140 deg. C), largely improved fracture resistance was observed. {yields} Annealing treatment is favorable for the improvement of the storage modulus of the immiscible polymer blend. - Abstract: As a part of serial work about the toughening of isotactic polypropylene (iPP) during annealing treatment, this work reports the effect of annealing on fracture behaviors of iPP blend with a little of poly(ethylene oxide) (PEO). Injection-molded bars of an iPP/PEO blend were annealed at different temperatures (50-160 deg. C) for 12 h and at 100 deg. C for different durations (12-96 h). The fracture behaviors of the annealed samples, including notched Izod impact fracture, universal tensile fracture, and single-edge notched tensile (SENT) fracture, were comparatively investigated to establish the role of annealing in improving the fracture resistance of the sample. The results showed that the annealing treatment greatly influences the fracture resistance of the blend. The impact-fractured surface morphologies were characterized by scanning electron microscope (SEM) to clarify the possible mechanisms for the improvement of the fracture resistance. It was proposed that, the excellent fracture resistance of iPP with a minor phase of which exhibits relatively low melting temperature can be easily achieved through the simple annealing treatment, even if the minor phase is immiscible with iPP.

  14. Post-annealing effects on pulsed laser deposition-grown GaN thin films

    International Nuclear Information System (INIS)

    Cheng, Yu-Wen; Wu, Hao-Yu; Lin, Yu-Zhong; Lee, Cheng-Che; Lin, Ching-Fuh

    2015-01-01

    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

  15. spsann - optimization of sample patterns using spatial simulated annealing

    Science.gov (United States)

    Samuel-Rosa, Alessandro; Heuvelink, Gerard; Vasques, Gustavo; Anjos, Lúcia

    2015-04-01

    There are many algorithms and computer programs to optimize sample patterns, some private and others publicly available. A few have only been presented in scientific articles and text books. This dispersion and somewhat poor availability is holds back to their wider adoption and further development. We introduce spsann, a new R-package for the optimization of sample patterns using spatial simulated annealing. R is the most popular environment for data processing and analysis. Spatial simulated annealing is a well known method with widespread use to solve optimization problems in the soil and geo-sciences. This is mainly due to its robustness against local optima and easiness of implementation. spsann offers many optimizing criteria for sampling for variogram estimation (number of points or point-pairs per lag distance class - PPL), trend estimation (association/correlation and marginal distribution of the covariates - ACDC), and spatial interpolation (mean squared shortest distance - MSSD). spsann also includes the mean or maximum universal kriging variance (MUKV) as an optimizing criterion, which is used when the model of spatial variation is known. PPL, ACDC and MSSD were combined (PAN) for sampling when we are ignorant about the model of spatial variation. spsann solves this multi-objective optimization problem scaling the objective function values using their maximum absolute value or the mean value computed over 1000 random samples. Scaled values are aggregated using the weighted sum method. A graphical display allows to follow how the sample pattern is being perturbed during the optimization, as well as the evolution of its energy state. It is possible to start perturbing many points and exponentially reduce the number of perturbed points. The maximum perturbation distance reduces linearly with the number of iterations. The acceptance probability also reduces exponentially with the number of iterations. R is memory hungry and spatial simulated annealing is a

  16. Influence of Annealing Temperature on the Characteristics of Ti-Codoped GZO Thin Solid Film

    Directory of Open Access Journals (Sweden)

    Tao-Hsing Chen

    2013-01-01

    Full Text Available This study utilizes radio frequency magnetron sputtering (RF sputtering to deposit GZO transparent conductive film and Ti thin film on the same corning glass substrate and then treats GZO/Ti thin film with rapid thermal annealing. The annealing temperatures are 300°C , 500°C, and 550°C, respectively. Ti:GZO transparent conductive oxide (TCO thin films are deposited on glass substrates using a radio frequency magnetron sputtering technique. The thin films are then annealed at temperatures of 300°C, 500°C, and 550°C, respectively, for rapid thermal annealing. The effects of the annealing temperature on the optical properties, resistivity, and nanomechanical properties of the Ti:GZO thin films are then systematically explored. The results show that all of the annealed films have excellent transparency (~90% in the visible light range. Moreover, the resistivity of the Ti:GZO films reduces with an increasing annealing temperature, while the carrier concentration and Hall mobility both increase. Finally, the hardness and Young’s modulus of the Ti:GZO thin films are both found to increase as the annealing temperature is increased.

  17. Influence of annealing temperature on ZnO thin films grown by dual ...

    Indian Academy of Sciences (India)

    In electrical characterization as well, when annealing temperature was increased from 400 to 600 °C, room temperature electron mobility enhanced from 6.534 to 13.326 cm2/V s, and then reduced with subsequent increase in temperature. Therefore, 600 °C annealing temperature produced good-quality ZnO film, suitable ...

  18. Microstructural evolution modelling of low carbon steel sheets during continuous annealing. Prediction of the mechanical properties

    International Nuclear Information System (INIS)

    Petite, M.M.; Monsalve, A.; Gutierrez, I.; Zaitegui, J.; Larburu, J.I.

    1998-01-01

    A model has been developed which allows the prediction of both, the evolution of the microstructure during continuous annealing and the final mechanical properties as a function of the steel composition, the variables defining the annealing cycle and those during hot and cold rolling. (Author) 10 refs

  19. Threefold atmospheric-pressure annealing for suppressing graphene nucleation on copper in chemical vapor deposition

    Science.gov (United States)

    Suzuki, Seiya; Nagamori, Takashi; Matsuoka, Yuki; Yoshimura, Masamichi

    2014-09-01

    Chemical vapor deposition (CVD) is a promising method of producing a large single-crystal graphene on a catalyst, especially on copper (Cu), and a further increase in domain size is desirable for electro/optic applications. Here, we report on threefold atmospheric-pressure (ATM) annealing for suppressing graphene nucleation in atmospheric CVD. Threefold ATM annealing formed a step and terrace surface of the underlying Cu, in contrast to ATM annealing. Atomic force microscopy and Auger electron mapping revealed that Si-containing particles existed on threefold-ATM- and ATM-annealed surfaces; particles on Cu had a lower density after threefold ATM annealing than after ATM annealing. The formation of a step and terrace surface and the lower density of particles following the threefold ATM annealing would play a role in reducing graphene nucleation. By combining threefold ATM annealing and electropolishing of Cu, the nucleation of graphene was effectively suppressed, and a submillimeter-sized hexagonal single-crystal graphene was successfully obtained.

  20. Effect of annealing temperature on the mechanical properties of Zircaloy-4 cladding

    International Nuclear Information System (INIS)

    Beauregard, R.J.; Clevinger, G.S.; Murty, K.L.

    1977-01-01

    The mechanical properties of Zircaloy cladding materials are sensitive to those fabrication variables which have an effect on the preferred crystallographic orientation or texture of the finished tube. The effect of one such variable, the final annealing temperature, on various mechanical properties is examined using tube reduced Zircaloy-4 fuel rod cladding annealed at temperatures from 905F to 1060F. This temperature range provides cladding with varying degrees of recrystallization including full recrystallization. The burst strength of the cladding at 650F decreased with the annealing temperature reaching a saturation value at approximately 1000F. The total circumferential elongation increased with the annealing temperature reaching a maximum at approximately 1000F and decreasing at higher temperatures. Hoop creep characteristics of Zircaloy cladding were studied as a function of the annealing temperature using closed-end internal pressurization tests at 750F and hoop stresses of 10, 15, 20 and 25 ksi. The effect of annealing temperature on the room temperature mechanical anisotropy parameters, R and P, was studied. The R-parameter was essentially independent of the annealing temperature while the P-parameter increased with annealing temperature. The mechanical anisotropy parameters were also studied as a function of the test temperature from ambient to approximately 800F using continuously monitored high precision extensometry. (Auth.)

  1. 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

  2. Surface Impedance of Copper MOB Depending on the Annealing Temperature and Deformation Degree

    International Nuclear Information System (INIS)

    Kutovoj, V.A.; Nikolaenko, A.A.; Stoev, P.I.; Vinogradov, D.V.

    2006-01-01

    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

  3. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  4. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Ц and 3000/1500 Е, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing methods were used to mix bilayer thin film structure.

  5. Synthesis and characterization of nanocrystalline vanadium oxide thin films: electrochemical behavior by annealing in different atmosphere

    Science.gov (United States)

    Asiabar, M. Amiri; Mohaghegh, Z.; Ghodsi, F. E.

    2018-01-01

    Nanocrystalline vanadium oxide thin films were prepared using sol-gel dip-coating technique. The effect of heat treatment in different environment including air, N2, Ar, and O2 gas on the structural, optical, electrical, and electrochemical properties of nanocrystalline vanadium oxide thin films were investigated. The results indicated that the calculated average crystallite size was reduced by annealing in Ar environment. Scanning electron microscopy (SEM) images showed layered morphology on the surface of the film annealed in air atmosphere, whereas the film annealed under Ar and N2 ambient revealed granular and wrinkle morphology, respectively. This morphology altered to rather smooth surface by annealing in O2 environment. The optical bandgap of the films were found to be 1.75, 1.84, 2.08, and 2.10 eV annealed in air, O2, N2, and Ar environment, respectively. It was observed that the films annealed under Ar and N2 ambient had low resistivity ( 0.2 Ω cm) and high carrier concentration, while the film annealed in nitrogen environment showed higher mobility of charge carrier. The electrochemical measurements showed that annealing under N2 ambient improved the intercalation of Li ions, leading a higher interfacial capacitance of 19.18 mF Cm-2, and decreased the charge transfer resistance due to surface defects created by heat treatment in nitrogen environment.

  6. Effect of annealing on properties of Mg doped Zn-ferrite nanoparticles

    Directory of Open Access Journals (Sweden)

    K. Nadeem

    2015-04-01

    Full Text Available A comparison of structural and magnetic properties of as-prepared and annealed (900 °C Mg doped Zn ferrite nanoparticles (Zn1−xMgxFe2O4, with x=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.

  7. 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 ...

  8. Effect of vacuum annealing on evaporated pentacene thin films for memory device applications

    International Nuclear Information System (INIS)

    Gayathri, A.G.; Joseph, C.M.

    2016-01-01

    Graphical abstract: Switching of ITO/pentacene/Al thin films for different annealing temperatures. - Highlights: • Memory device performance in pentacene improved considerably with annealing. • ON/OFF ratio of the pentacene device increases due to annealing. • Threshold voltage reduces from 2.55 V to 1.35 V due to annealing. • Structure of pentacene thin films is also dependent on annealing temperature. - Abstract: Thin films of pentacene were deposited thermally onto glass substrates and annealed at 323 K, 373 K, 423 K, 473 K and 523 K in high vacuum. Effect of annealing on the morphological and structural properties of these films was studied. X-ray diffraction patterns confirmed the crystalline nature of the films. Electrical studies for the use as write once read many (WORM) memory devices were done for the vacuum deposited pentacene thin films on indium tin oxide coated glass. Due to annealing, a sharp increase in the ON/OFF ratio of current and a decrease in threshold voltage were observed at around 373 K. This device showed a stable switching with an ON/OFF current ratio as high as 10 9 and a switching threshold voltage of 1.35 V. The performance of the device degraded above 423 K due to the changes in the crystallinity of the film.

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

    Indian Academy of Sciences (India)

    Unknown

    anneal of 10 h followed by annealing of 10 h ... But it leaves some problems with a mark of interrogation, such as the exact kinetics of thermal ... desired heat treatment and the concentrations of oxygen. (Oi) and carbon (Cs) are again measured with ...

  10. Enhanced bulk heterojunction devices prepared by thermal and solvent vapor annealing processes

    Science.gov (United States)

    Forrest, Stephen R.; Thompson, Mark E.; Wei, Guodan; Wang, Siyi

    2017-09-19

    A method of preparing a bulk heterojunction organic photovoltaic cell through combinations of thermal and solvent vapor annealing are described. Bulk heterojunction films may prepared by known methods such as spin coating, and then exposed to one or more vaporized solvents and thermally annealed in an effort to enhance the crystalline nature of the photoactive materials.

  11. Electrical behavior of amide functionalized graphene oxide and graphene oxide films annealed at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Sumita; Kumar, Mukesh, E-mail: kumarmukesh@gmail.com; Kumar, Dinesh; Sharma, Sumit

    2015-06-30

    Films of graphene oxide (GO) and amide functionalized graphene oxides (AGOs) were deposited on SiO{sub 2}/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.

  12. Large Deviations for the Annealed Ising Model on Inhomogeneous Random Graphs: Spins and Degrees

    Science.gov (United States)

    Dommers, Sander; Giardinà, Cristian; Giberti, Claudio; Hofstad, Remco van der

    2018-04-01

    We prove a large deviations principle for the total spin and the number of edges under the annealed Ising measure on generalized random graphs. We also give detailed results on how the annealing over the Ising model changes the degrees of the vertices in the graph and show how it gives rise to interesting correlated random graphs.

  13. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Keywords. AlSb; thin film; RBS; optical band gap. Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Å and 3000/1500 Å, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing ...

  14. Effect of annealing on phase transition in poly(vinylidene fluoride)

    Indian Academy of Sciences (India)

    Here we report the crystallization of both and -phase PVDF films by varying preparation temperature using DMSO solvent. The -phase PVDF films were annealed at 70, 90, 110, 130 and 160°C for five hours. The changes in the phase contents in the PVDF at different annealing conditions have been described.

  15. Evolution of Residual Stress and Distortion of Cold-Rolled Bearing Ring from Annealing to Quenched-Tempered Heat Treatment

    Science.gov (United States)

    Lu, Bohan; Lu, Xiaohui

    2018-02-01

    This study investigates the correlation between the residual stress and distortion behavior of a cold-rolled ring from the annealing to quenching-tempering (QT) process. Due to the cold-rolled process, the external periphery of the bearing ring experiences a compressive residual stress. To relieve the residual stress, cold-rolled rings are annealed at 700 °C which is higher than the starting temperature of recrystallization. When cold-rolled rings are annealed at 700 °C for 15 min, the compressive residual stress is reduced to zero and the outer diameter of the annealed ring becomes larger than that of a non-annealed sample, which is unrelated to annealing time. Simultaneously, the roundness and taper deviation do not obviously change compared with those of non-annealed sample. The stress relaxation during the annealing process was attributed to the recovery and recrystallization of ferrite. Annealing has a genetic influence on the following QT heat treatment, wherein the lowest residual stress is in the non-annealed cold-rolled ring. From the annealing to QT process, the deviation of the outer diameter, roundness, and taper increased with annealing time, a large extend than that of non-annealed samples.

  16. 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

  17. Hardness evolution on annealing in AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Lopez, A.; Alvarez de Sotomayor, A.; Herrera, E. J.

    2001-01-01

    The evolution of the microstructure and hardness of commercial AISI 304 stainless-steel samples with the heat treatment has been studied. Steel specimens in the as-received condition, and after 50% cold rolling, were soaked for 1 hour at various temperatures between 650 and 1200 degree centigree Samples maintain their grain size and hardness until about 900 degree centigree, thereafter, size increases with temperature, while hardness lightly diminishes. Recrystallization of cold-rolled specimens begins at 650 degree centigree, and finishes around 850 degree centigree. Recrystallized grain-size reaches the value found in the as received materials after the treatment at 900 degree centigree. For high her annealing temperatures both grain growth and hardness decrease following the same trend in cold-worked and non-deformed materials. (Author) 10 refs

  18. Geometric Optimization of Thermo-electric Coolers Using Simulated Annealing

    Science.gov (United States)

    Khanh, D. V. K.; Vasant, P. M.; Elamvazuthi, I.; Dieu, V. N.

    2015-09-01

    The field of thermo-electric coolers (TECs) has grown drastically in recent years. In an extreme environment as thermal energy and gas drilling operations, TEC is an effective cooling mechanism for instrument. However, limitations such as the relatively low energy conversion efficiency and ability to dissipate only a limited amount of heat flux may seriously damage the lifetime and performance of the instrument. Until now, many researches were conducted to expand the efficiency of TECs. The material parameters are the most significant, but they are restricted by currently available materials and module fabricating technologies. Therefore, the main objective of finding the optimal TECs design is to define a set of design parameters. In this paper, a new method of optimizing the dimension of TECs using simulated annealing (SA), to maximize the rate of refrigeration (ROR) was proposed. Equality constraint and inequality constraint were taken into consideration. This work reveals that SA shows better performance than Cheng's work.

  19. 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.

  20. Structural relaxation dynamics and annealing effects of sodium silicate glass.

    Science.gov (United States)

    Naji, Mohamed; Piazza, Francesco; Guimbretière, Guillaume; Canizarès, Aurélien; Vaills, Yann

    2013-05-09

    Here we report high-precision measurements of structural relaxation dynamics in the glass transition range at the intermediate and short length scale for a strong sodium silicate glass during long annealing times. We evidence for the first time the heterogeneous dynamics at the intermediate range order by probing the acoustic longitudinal frequency in the GHz region by Brillouin light scattering spectroscopy. Or, from in-situ Raman measurements, we show that relaxation is indeed homogeneous at the interatomic length scale. Our results show that the dynamics at the intermediate range order contains two distinct relaxation time scales, a fast and a slow component, differing by about a 10-fold factor below Tg and approaching to one another past the glass transition. The slow relaxation time agrees with the shear relaxation time, proving that Si-O bond breaking constitutes the primary control of structural relaxation at the intermediate range order.

  1. Lasing of Some Red Laser Dyes in Annealed Silica Xerogel

    Science.gov (United States)

    Bezkrovnaya, O. N.; Maslov, V. V.; Pritula, I. M.; Yurkevich, A. G.

    2018-01-01

    The spectral and energy characteristics of generation in the red spectral region 650-720 nm were measured and analyzed for three laser dyes in preliminarily annealed SiO2 xerogel matrices under laser excitation λp = 588 nm in a nonselective cavity. The specific laser-energy output for two of them (LK678 and Ox170) in the matrices was 10-13% higher than in MeOH. NBA dye in the matrix generated two laser radiation bands in the 700-720 nm region with pumping E p ≥ 80 mJ whereas its generation threshold in MeOH exceeded the maximum pumping energy of 140 mJ so that NBA generation was not observed. Laser emission spectra of the studied matrices in a nonselective cavity were red-shifted by 1000 cm-1 from the fluorescence maximum. Such a shift could improve the characteristics of biosensors based on these matrices.

  2. Positron annihilation studies on reactor irradiated and thermal annealed ferrocene

    International Nuclear Information System (INIS)

    Marques Netto, A.; Carvalho, R.S.; Magalhaes, W.F.; Sinisterra, R.D.

    1996-01-01

    Retention and thermal annealing following (n, γ) reaction in solid ferrocene, Fe(C 5 H 5 ) 2 , were studied by positron annihilation lifetime spectroscopy (PAL). Positronium (Ps) formation was observed in the non-irradiated compound with a probability or intensity (I 3 ) of 30%. Upon irradiation of the compound with thermal neutrons in a nuclear reactor, I 3 decreases with increasing irradiation time. Thermal treatment again increases I 3 values from 16% to 25%, revealing an important proportion of molecular reformation without variation of the ortho-positronium lifetime (τ 3 ). These results point out the major influence of the electronic structure as determining the Ps yields in the pure complex. In the irradiated and non irradiated complexes the results are satisfactorily explained on the basis of the spur model. (orig.)

  3. Experimental study of swelling of irradiated solid methane during annealing

    International Nuclear Information System (INIS)

    Shabalin, E.; Fedorov, A.; Kulagin, E.; Kulikov, S.; Melikhov, V.; Shabalin, D.

    2008-01-01

    Solid methane is still widely in use at pulsed neutron sources due to its excellent neutronic performance (IPNS, KENS, Second Target Station at ISIS), notwithstanding poor radiation properties. One of the specific problems is radiolytic hydrogen gas pressure on the walls of a methane chamber during annealing of methane. In this paper results of an experimental study of this phenomenon under fast neutron irradiation with the help of a specially made low temperature irradiation rig at the IBR-2 pulsed reactor are presented. The peak pressure on the wall of the experimental capsule during heating of a sample irradiated at 23-35 K appears to have a maximum of 2.7 MPa at an absorbed dose 20 MGy and then falls down with higher doses. The pressure always reached its peak value at the temperature range 72-79 K. Generally, three phases of methane swelling during heating can be distinguished, each characterized by a proper rate and intensity.

  4. 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...... microscopy (AFM) and scanning electron microscopy (SEM) images. Raman spectroscopy is used to examine the sulfur distribution between the surface and the bottom of the film. Compositional changes are monitored by energy dispersive X-ray spectroscopy (EDX) and the crystallinity by X-ray diffraction (XRD......). 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...

  5. 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...... applications. However, when a wider absorption frequency band is required, it is necessary to design multiple-layer MPP (ML-MPP). The design of an N-layers MPP depends on 4N parameters. Consequently, the tuning of an optimal ML-MPP by exhaustive search within a prescribed frequency band becomes impractical....... 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....

  6. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Mihailova, Boriana [Hamburg Univ. (Germany). Dept. of Earth Sciences; Beirau, Tobias [Hamburg Univ. (Germany). Dept. of Earth Sciences; Stanford Univ., CA (United States). Dept. of Geological Sciences; and others

    2017-03-01

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1.10{sup 18} α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28%, Blue River 85% and Miass 100% according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (M. T. Vandenborre, E. Husson, Comparison of the force field in various pyrochlore families. I. The A{sub 2}B{sub 2}O{sub 7} oxides. J. Solid State Chem. 1983, 50, 362, S. Moll, G. Sattonnay, L. Thome, J. Jagielski, C. Decorse, P. Simon, I. Monnet, W. J. Weber, Irradiation damage in Gd{sub 2}Ti{sub 2}O{sub 7} single crystals: Ballistic versus ionization processes. Phys. Rev. 2011, 84, 64115.), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} divided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K

  7. A simulated annealing approach for redesigning a warehouse network problem

    Science.gov (United States)

    Khairuddin, Rozieana; Marlizawati Zainuddin, Zaitul; Jiun, Gan Jia

    2017-09-01

    Now a day, several companies consider downsizing their distribution networks in ways that involve consolidation or phase-out of some of their current warehousing facilities due to the increasing competition, mounting cost pressure and taking advantage on the economies of scale. Consequently, the changes on economic situation after a certain period of time require an adjustment on the network model in order to get the optimal cost under the current economic conditions. This paper aimed to develop a mixed-integer linear programming model for a two-echelon warehouse network redesign problem with capacitated plant and uncapacitated warehouses. The main contribution of this study is considering capacity constraint for existing warehouses. A Simulated Annealing algorithm is proposed to tackle with the proposed model. The numerical solution showed the model and method of solution proposed was practical.

  8. Large-area field emission diode for semiconductor annealing

    Science.gov (United States)

    Luches, A.; Nassisi, V.; Perrone, A.; Perrone, M. R.

    1981-03-01

    We report the characteristics of a low energy electron beam generator used for annealing of materials of interest as electron devices and photovoltaic cells. The high voltage pulser is a two-stage Marx circuit which supplies 10-50 kV pulses. A Blumlein line gives the pulses an almost square shape and a length of 50 ns. This short pulse is applied to a field emission diode. Various kinds of cathodes are used. They deliver electron pulses of up to 20 kA. Tungsten needles are used for small-area beams and blade arrays or graphite cathodes for large-area beams. Consequently, the beam diameter can vary from 2 to 120 mm with a good beam homogeneity. The anode is movable to vary the vacuum diode impedance and consequently the current-voltage characteristic of the electron beam. Energy densities varying from 0.1 to 100 J/cm 2 are obtained on the anode. The anode can be formed by a semiconductor monocrystalline wafer. We used crystalline silicon wafers covered by a thin (≈100 nm) layer of vacuum deposited near-noble and refractory metals. Under electron beam bombardment with discharge energy densities ranging from 0.4 to 10 J/cm 2, silicide formation is evident over all the annealed anodes. Metastable compounds are formed because of the fast heating and cooling rates. Silicon monocrystalline wafers, doped with 10 14-10 15 ions/cm 2 of B or P ions exhibit a complete recovery of their crystalline structure after a single discharge.

  9. Manipulation of magnetic properties of glass-coated microwires by annealing

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, A., E-mail: arkadi.joukov@ehu.es [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20009 San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain); Chichay, K. [Immanuel Kant Baltic Federal University, 236041 Kaliningrad (Russian Federation); Talaat, A. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20009 San Sebastian (Spain); Rodionova, V. [Immanuel Kant Baltic Federal University, 236041 Kaliningrad (Russian Federation); National University of Science and Technology (MISIS), 119049 Moscow (Russian Federation); Blanco, J.M. [Dpto. Física Aplicada, EUPDS Basque Country University UPV/EHU (Spain); Ipatov, M.; Zhukova, V. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, 20009 San Sebastian (Spain)

    2015-06-01

    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.

  10. High-temperature laser annealing for thin film polycrystalline silicon solar cell on glass substrate

    Science.gov (United States)

    Chowdhury, A.; Schneider, J.; Dore, J.; Mermet, F.; Slaoui, A.

    2012-06-01

    Thin film polycrystalline silicon films grown on glass substrate were irradiated with an infrared continuous wave laser for defects annealing and/or dopants activation. The samples were uniformly scanned using an attachment with the laser system. Substrate temperature, scan speed and laser power were varied to find suitable laser annealing conditions. The Raman spectroscopy and Suns- V oc analysis were carried out to qualify the films quality after laser annealing. A maximum enhancement of the open circuit voltage V oc of about 100 mV is obtained after laser annealing of as-grown polysilicon structures. A strong correlation was found between the full width half maximum of the Si crystalline peak and V oc. It is interpreted as due to defects annealing as well as to dopants activation in the absorbing silicon layer. The maximum V oc reached is 485 mV after laser treatment and plasma hydrogenation, thanks to defects passivation.

  11. Effect of thermal annealing on the surface properties of electrospun polymer fibers.

    Science.gov (United States)

    Chen, Jiun-Tai; Chen, Wan-Ling; Fan, Ping-Wen; Yao, I-Chun

    2014-02-01

    Electrospun polymer fibers are gaining importance because of their unique properties and applications in areas such as drug delivery, catalysis, or tissue engineering. Most studies to control the morphology and properties of electrospun polymer fibers focus on changing the electrospinning conditions. The effects of post-treatment processes on the morphology and properties of electrospun polymer fibers, however, are little studied. Here, the effect of thermal annealing on the surface properties of electrospun polymer fibers is investigated. Poly(methyl methacrylate) and polystyrene fibers are fist prepared by electrospinning, followed by thermal annealing processes. Upon thermal annealing, the surface roughness of the electrospun polymer fibers decreases. The driving force of the smoothing process is the minimization of the interfacial energy between polymer fibers and air. The water contact angles of the annealed polymer fibers also decrease with the annealing time. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths.

    Science.gov (United States)

    Pospori, A; Marques, C A F; Sagias, G; Lamela-Rivera, H; Webb, D J

    2018-01-22

    The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting.

  13. The post-annealing environment effect on the photoluminescence recovery of ion-irradiated Si nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Sias, U.S. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil) and Centro Federal de Educacao Tecnologica de Pelotas (CEFET-RS), 96015-370 Pelotas, RS (Brazil)]. E-mail: uilson@cefetrs.tche.br; Behar, M. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Boudinov, H. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Moreira, E.C. [UFPel - UNIPAMPA, Campus Bage, 96400-970 Bage, RS (Brazil)

    2007-04-15

    In the present work we have investigated the influence of the post-annealing environment on the photoluminescence (PL) recovery of Si nanocrystals after ion irradiation. Samples originally produced by Si implantation into SiO{sub 2} matrix at 600 deg. C post-annealed at 1100 deg. C were further bombarded with 2 MeV Si{sup +}, at a fluence of {phi} = 2 x 10{sup 13} Si/cm{sup 2}. After irradiation the original emission, composed by two PL bands, was completely quenched. We shown that the environment of a post-annealing performed at 900 deg. C has a strong effect on the PL emission recovery. The intensity and shape of the PL spectra have revealed to be dependent of the annealing gas (N{sub 2} or Ar), annealing time, as well as the original Si excess. The results are explained on the basis of current theories.

  14. Quantum annealing versus classical machine learning applied to a simplified computational biology problem

    Science.gov (United States)

    Li, Richard Y.; Di Felice, Rosa; Rohs, Remo; Lidar, Daniel A.

    2018-01-01

    Transcription factors regulate gene expression, but how these proteins recognize and specifically bind to their DNA targets is still debated. Machine learning models are effective means to reveal interaction mechanisms. Here we studied the ability of a quantum machine learning approach to predict binding specificity. Using simplified datasets of a small number of DNA sequences derived from actual binding affinity experiments, we trained a commercially available quantum annealer to classify and rank transcription factor binding. The results were compared to state-of-the-art classical approaches for the same simplified datasets, including simulated annealing, simulated quantum annealing, multiple linear regression, LASSO, and extreme gradient boosting. Despite technological limitations, we find a slight advantage in classification performance and nearly equal ranking performance using the quantum annealer for these fairly small training data sets. Thus, we propose that quantum annealing might be an effective method to implement machine learning for certain computational biology problems. PMID:29652405

  15. Manipulation of magnetic properties of glass-coated microwires by annealing

    International Nuclear Information System (INIS)

    Zhukov, A.; Chichay, K.; Talaat, A.; Rodionova, V.; Blanco, J.M.; Ipatov, M.; Zhukova, V.

    2015-01-01

    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

  16. Effect of Intermediate Annealing on Microstructure and Property of 5182 Aluminum Alloy Sheet for Automobile

    Directory of Open Access Journals (Sweden)

    WANG Yu

    2016-09-01

    Full Text Available Effect of intermediate annealing on the microstructure and properties of 5182 aluminum alloy sheet with full annealed state (5182-O was investigated by means of optical microscope, scanning electron microscope and universal testing machine. The results indicate that compared with 5182-O sheet without intermediate annealing, 5182-O sheet with intermediate annealing possesses too fine grain size, intermetallic compounds not broken enough, larger size intermetallic particles, less dispersed phase. Yield strength and ultimate tensile strength, work hardening exponent and normal anisotropy of plastic strain ratio decrease but planner anisotropy of plastic strain ratio increases. The mechanical properties and forming ability of 5182-O aluminum alloy sheet and its microstructure are not improved significantly after intermediate annealing.

  17. Sensitivity enhancement using annealed polymer optical fibre based sensors for pressure sensing applications

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Saez-Rodriguez, D.

    2016-01-01

    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...

  18. An automated ion implant/pulse anneal machine for low cost silicon cell production

    International Nuclear Information System (INIS)

    Armini, A.J.; Bunker, S.N.; Spitzer, M.B.

    1982-01-01

    The continuing development of a high throughput ion implanter and a pulsed electron beam annealer designed for dedicated silicon solar cell manufacture is reviewed. This equipment is intended for production of junctions in 10 cm wide wafers at a throughput up to 10 MWsub(p) per year. The principal features of the implanter are the lack of mass analysis and defocusing utilizing electrostatic deflection. The implanted surface is annealed by liquid phase epitaxy resulting from a single burst of a large area electron beam. Cells with non-mass analyzed ion implantation have yielded AM1 cell efficiencies in excess of 15%. Pulse annealed Czochralski cells have been made with AM1 efficiencies of 13% vs. 15% for a furnace annealed group. Results of pulse annealing of polycrystalline materials indicate that cell performance comparable to diffusion can be obtained. (Auth.)

  19. Effect of annealing time on morphological characteristics of Ba(Zr,Ti)O3 thin films

    International Nuclear Information System (INIS)

    Cavalcante, L.S.; Anicete-Santos, M.; Pontes, F.M.; Souza, I.A.; Santos, L.P.S.; Rosa, I.L.V.; Santos, M.R.M.C.; Santos-Junior, L.S.; Leite, E.R.; Longo, E.

    2007-01-01

    Ba(Zr 0.50 Ti 0.50 )O 3 thin films were prepared by the polymeric precursor method using the annealing low temperature of 300 o C for 8, 16, 24, 48, 96 and 192h in a furnace tube with oxygen atmosphere. The X-ray diffraction patterns revealed that the film annealed for 192 h presented some crystallographic planes (1bar 0bar 0) (1bar 1bar 0) and (2bar 0bar 0) in its crystalline lattice. Fourier transformed infrared presented the formation of metal-oxygen stretching at around 756cm -1 . The atomic force microscopy analysis presented the growth of granules in the Ba(Zr 0.50 Ti 0.50 )O 3 films annealed from 8 to 96h. The crystalline film annealed for 192h already presents grains in its perovskite structure. It evidenced a reduction in the thickness of the thin films with the increase of the annealing time

  20. Annealing bounds to prevent further Charge Transfer Inefficiency increase of the Chandra X-ray CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Monmeyran, Corentin, E-mail: comonmey@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Patel, Neil S., E-mail: neilp@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bautz, Mark W., E-mail: mwb@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Grant, Catherine E., E-mail: cgrant@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Prigozhin, Gregory Y., E-mail: gyp@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Agarwal, Anuradha, E-mail: anu@mit.edu [Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Kimerling, Lionel C., E-mail: lckim@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-12-15

    After the front-illuminated CCDs on board the X-ray telescope Chandra were damaged by radiation after launch, it was decided to anneal them in an effort to remove the defects introduced by the irradiation. The annealing led to an unexpected increase of the Charge Transfer Inefficiency (CTI). The performance degradation is attributed to point defect interactions in the devices. Specifically, the annealing at 30 °C activated the diffusion of the main interstitial defect in the device, the carbon interstitial, which led to its association with a substitutional impurity, ultimately resulting in a stable and electrically active defect state. Because the formation reaction of this carbon interstitial and substitutional impurity associate is diffusion limited, we recommend a higher upper bound for the annealing temperature and duration of any future CCD anneals, that of −50 °C for one day or −60 °C for a week, to prevent further CTI increase.

  1. Effect of Different Post Deposition Annealing Treatments on Properties of Zinc Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    Arti Arora

    2010-06-01

    Full Text Available Two different post deposition annealing atmospheres of oxygen and forming gas have been investigated for the improvement of rf sputtered zinc oxide thin films. The results show that type of atmosphere (oxidant o reduction plays an important role in the changes observed in structural, electrical and optical properties. It has been found that the structural properties of rf sputtered zinc oxide films improve in all the annealing environments. The intensity and grain size increases as the annealing temperature increases. It has been found that films become stress free at lowest temperature in oxygen as compare to forming gas annealing. The zinc oxide films annealed in oxygen shows sufficient resistivity associated to high transmittance (83 % characteristics required for MEMS based acoustic devices.

  2. Propagating self-sustained annealing of radiation-induced interstitial complexes

    International Nuclear Information System (INIS)

    Bokov, P M; Selyshchev, P A

    2016-01-01

    A propagating self-sustained annealing of radiation induced defects as a result of thermal-concentration instability is studied. The defects that are considered in the model are complexes. Each of them consists of one atom of impunity and of one interstitial atom. Crystal with defects has extra energy which is transformed into heat during defect annealing. Simulation of the auto-wave of annealing has been performed. The front and the speed of the auto-wave have been obtained. It is shown that annealing occurs in a narrow region of time and space. There are two kinds of such annealing behaviour. In the first case the speed of the auto-wave oscillates near its constant mean value and the front of temperature oscillates in a complex way. In the second case the speed of propagation is constant and fronts of temperature and concentration look like sigmoid functions. (paper)

  3. Annealing effects on the migration of ion-implanted cadmium in glassy carbon

    Energy Technology Data Exchange (ETDEWEB)

    Hlatshwayo, T.T., E-mail: thulani.hlatshwayo@up.ac.za [Physics Department, University of Pretoria, Pretoria (South Africa); Sebitla, L.D. [Physics Department, University of Pretoria, Pretoria (South Africa); Physics Department, University of Botswana, Gaborone (Botswana); Njoroge, E.G.; Mlambo, M.; Malherbe, J.B. [Physics Department, University of Pretoria, Pretoria (South Africa)

    2017-03-15

    The migration behaviour of cadmium (Cd) implanted into glassy carbon and the effects of annealing on radiation damage introduced by ion implantation were investigated. The glassy carbon substrates were implanted with Cd at a dose of 2 × 10{sup 16} ions/cm{sup 2} and energy of 360 keV. The implantation was performed at room temperature (RT), 430 °C and 600 °C. The RT implanted samples were isochronally annealed in vacuum at 350, 500 and 600 °C for 1 h and isothermally annealed at 350 °C up to 4 h. The as-implanted and annealed samples were characterized by Raman spectroscopy and Rutherford backscattering spectrometry (RBS). Raman results revealed that implantation at room temperature amorphized the glassy carbon structure while high temperature implantations resulted in slightly less radiation damage. Isochronal annealing of the RT implanted samples resulted in some recrystallization as a function of increasing temperature. The original glassy carbon structure was not achieved at the highest annealing temperature of 600 °C. Diffusion of Cd in glassy carbon was already taking place during implantation at 430 °C. This diffusion of Cd was accompanied by significant loss from the surface during implantation at 600 °C. Isochronal annealing of the room temperature implanted samples at 350 °C for 1 h caused Cd to diffuse towards the bulk while isothermal annealing at 500 and 600 °C resulted in the migration of implanted Cd toward the surface accompanied by a loss of Cd from the surface. Isothermal annealing at 350 °C for 1 h caused Cd to diffuse towards the bulk while for annealing time >1 h Cd diffused towards the surface. These results were interpreted in terms of trapping and de-trapping of implanted Cd by radiation damage.

  4. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L., E-mail: TA@asu.edu [School of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor Inc., 1300 N. Alma School Rd., Chandler, Arizona 85224 (United States); Lu, Wei; Lau, S. S. [Department of Electrical Engineering, University of California, San Diego, California 92093 (United States); Lanz, A. [Department of Mathematics, Norfolk State University, Norfolk, Virginia 23504 (United States)

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  5. Microstructural evolution and pitting resistance of annealed lean duplex stainless steel UNS S32304

    International Nuclear Information System (INIS)

    Zhang Ziying; Han Dong; Jiang Yiming; Shi Chong; Li Jin

    2012-01-01

    Highlights: ► The relationship between pitting corrosion resistance and annealing temperature for UNS S32304 was systemically studied. ► The specimens annealed at 1080 °C for 1 h, quenched in water exhibit the best pitting corrosion resistance. ► The relationship between microstructural evolution and pitting resistance of annealed UNS S32304 was discussed in detail. ► The pitting corrosion resistance is consistent with pitting resistance equivalent number of weaker phase for UNS S32304 alloy. - Abstract: The effect of annealing temperature in the range from 1000 to 1200 °C on the pitting corrosion behavior of duplex stainless steel UNS S32304 was investigated by the potentiodynamic polarization and potentiostatic critical pitting temperature techniques. The microstructural evolution and pit morphologies were studied using a scanning electron microscopy with energy dispersive X-ray spectroscopy. The results demonstrated that the nucleation of metastable pits transformed from austenite phase to ferrite phase with the increasing annealing temperature. As the annealing temperature increased, the pitting corrosion resistance firstly increased and then decreased. The highest pitting corrosion resistance was obtained at 1080 °C with the highest critical pitting temperature value and pitting nucleation resistance. The results could be well explained by the microstructural evolution of ferrite and austenite phases induced by annealing treatment.

  6. Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, A. [IITB-Monash Research Academy, IIT Bombay (India); Department of Metallurgical Engineering and Materials Science, IIT Bombay (India); Department of Materials Engineering, Monash University (Australia); Samajdar, I. [Department of Metallurgical Engineering and Materials Science, IIT Bombay (India); Nie, J.F. [Department of Materials Engineering, Monash University (Australia); Tewari, A., E-mail: asim.tewari@iitb.ac.in [Department of Mechanical Engineering, IIT Bombay (India)

    2016-04-15

    The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrasting behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.

  7. Effect of annealing temperature on a polycrystalline lead oxide film derived by using the sedimentation method

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang-Sik; Choi, Young-Zun; Lee, Mi-Hyun; Jung, Bong-Jae; Park, Ji-Koon [International University of Korea, Jinju (Korea, Republic of); Nam, Sang-Hee; Cho, Kyu-Seuk [InJe University, Gimhae (Korea, Republic of)

    2011-12-15

    Polycrystalline PbO has a low effective work function, a high atomic number and the possibility of large-area deposition. In this research, fine lead-oxide particles were synthesized using a solution-combustion method, and PbO films of 200 {mu}m in thickness were deposited by a special wet sedimentation coating process at room temperature. The influences of annealing temperature on the X-ray detection properties of the film were investigated in detail. From the experimental results, the dark current was stable in about 0.4 second at a 500 .deg. C annealing temperature, but with no annealing, several tens of seconds were required for dark-current stability. In addition, the dark current density decreased rapidly with increasing annealing temperature, and the value was below 2 nA/cm{sup 2} after 300 .deg. C annealing. The X-ray sensitivity was about 2 {approx} 4 nC/mR-cm{sup 2} at 500 .deg. C annealing and this value is higher by 10 time than that of a commercial 500 {mu}m a-Se film. Finally, the signal loss of the 300 {approx} 500 .deg. C annealed sample was lower by 2% at five continuous X-ray exposures.

  8. Buffer layer annealing effects on the magnetization reversal process in Pd/Co/Pd systems

    Energy Technology Data Exchange (ETDEWEB)

    Fassatoui, A., E-mail: Fassatouiaymen@Hotmail.com [LMOP: LR99ES17, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunis, 2092 (Tunisia); Belhi, R. [LMOP: LR99ES17, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunis, 2092 (Tunisia); Vogel, J. [Institut Néel (CNRS and Université Grenoble Alpes), 25 rue des Martyrs, B. P. 166, Grenoble cedex 9, 38042 (France); Abdelmoula, K. [LMOP: LR99ES17, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunis, 2092 (Tunisia)

    2016-12-15

    We have investigated the effect of annealing the buffer layer on the magnetization reversal behavior in Pd/Co/Pd thin films using magneto-optical Kerr microscopy. It was found that annealing the buffer layer at 150 °C for 1 h decreases the coercivity and increases the saturation magnetization and the effective magnetic anisotropy constant. This study also shows that the annealing induces a change of the magnetization reversal from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation. This result demonstrates that the main effect of annealing the buffer layer is to decrease the domain wall pinning in the Co layer, favoring the domain wall propagation mode. - Highlights: • The buffer layer surface morphology changes upon annealing of the buffer layer. • The coercivity decreases while the saturation magnetization and the effective anisotropy increase with the annealing of the buffer layer. • The reversal process changes from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation when annealing the buffer layer.

  9. Resistivity behavior in isothermal annealing of Pd-H(D) alloys around 50 K

    International Nuclear Information System (INIS)

    Yamakawa, Kohji; Maeta, Hiroshi

    2004-01-01

    The behavior of electrical resistivity during hydrogen (deuterium) ordering is investigated for Pd-H(D) alloys of various hydrogen concentrations around 50 K. The disordered hydrogen (deuterium) atoms are introduced by quenching from 100 K into liquid helium immediately before isothermal annealings. The disordered atoms order by migration of the atoms during the heating-up of the specimens. On the isothermal curves of the resistivity in the high temperature range, the resistivity increases at first and then adopts a constant value dependent on the annealing temperature. On the other hand, the resistivity increases and then decreases during isothermal annealing in the low temperature range, nevertheless the ordering is progressing. The annealing time, at which the resistivity maximum appears, and the resistivity value of the maximum increase with decreasing annealing temperature. Furthermore, the decreasing resistivity after the maximum saturates to a value dependent on each annealing temperature. Therefore, it becomes clear that an equilibrium amount of ordering depends on the temperature and the resistivity increases in the early stage of hydrogen (deuterium) ordering and decreases in the later stage. The resistivity maximum in the isothermal annealing curve is caused by the nucleation and growth of ordered domains of hydrogen (deuterium) atoms

  10. Influence of post irradiation annealing on the mechanical properties and defect structure of AISI 304 steel

    Science.gov (United States)

    Van Renterghem, W.; Al Mazouzi, A.; Van Dyck, S.

    2011-06-01

    The effect of post irradiation annealing on the mechanical properties and the radiation induced defect structure was investigated on stainless steel, of type AISI 304, that was irradiated up to 24 dpa in the decommissioned Chooz A reactor. The material was investigated both in the as-irradiated state as well as after post irradiation annealing. In the as-irradiated specimen the typical radiation induced defects were found as well as γ'-precipitates (Ni 3Si). Annealing at 400 °C had almost no effect on the radiation induced defects, but annealing at 500 °C resulted in the immediate unfaulting of the Frank loops. As to the mechanical properties, annealing at 400 °C did not strongly affect the yield strength and the ductility of the material, although the fraction of intergranular fracture during slow strain rate tensile tests under pressurised water reactor conditions, was significantly reduced. Annealing at 500 °C did reduce the yield strength and restored substantially the ductility and the strain hardening capability of the material. The microstructure investigated by transmission electron microscopy correlates to the mechanical test results. It was found that the observed defect changes after post irradiation annealing provide a reasonable explanation for the observed changes of the mechanical properties.

  11. Structural, Optical, and Dielectric Properties of Azure B Thin Films and Impact of Thermal Annealing

    Science.gov (United States)

    Zeyada, H. M.; Zidan, H. M.; Abdelghany, A. M.; Abbas, I.

    2017-07-01

    Thin films of azure B (AB) have been prepared by thermal evaporation. Structural, optical, and dielectric characteristics of as-prepared and annealed samples were studied. AB is polycrystalline in as-synthesized powder form. Detailed x-ray diffraction studies showed amorphous structure for pristine and annealed films. Fourier-transform infrared vibrational spectroscopy indicated minor changes in molecular bonds of AB thin films either after deposition or after thermal annealing. Optical transmittance and reflection spectra of prepared thin films were studied at nearly normal light incidence in the spectral range from 200 nm to 2500 nm, showing marked changes without new peaks. Annealing increased the absorption coefficient and decreased the optical bandgap. Onset and optical energy gaps of pristine films were found to obey indirect allowed transition with values of 1.10 eV and 2.64 eV, respectively. Annealing decreased the onset and optical energy gaps to 1.0 eV and 2.57 eV, respectively. The dispersion parameters before and after annealing are discussed in terms of a single-oscillator model. The spectra of the dielectric constants ( ɛ 1, ɛ 2) were found to depend on the annealing temperature in addition to the incident photon energy.

  12. Impact of Annealing Thin Films In(OHxSy Growth By Solution Technique

    Directory of Open Access Journals (Sweden)

    Cliff Orori Mosiori

    2017-07-01

    Full Text Available Indium Hydroxy Sulphide has demonstrated abundance in resources, low prices, nontoxic characteristics, radiation resistance, high temperature resistance, and chemical stability, and therefore it has become an extremely important photoelectric, photovoltaic, and light sensing thin film material. Some treatment on this material include thermal annealing which is a process used for intrinsic stress liberation, structural improving, and surface roughness to control its electro-optical properties. In a qualitative way, annealing modifies surface morphology, intrinsic parameters, and electron mobility with temperature and time. In this work, an explanation on the surface modification of In(OHxSy thin films when subjected to an annealing process is discussed. Both electrical and optical effects caused by annealing were carried out and characterizations were performed at different annealing temperatures in nitrogen in the temperature range 373–573 K. Using optical measurements data and simulated data, Scout software was employed and the results showed that increasing annealing temperature causes a slight decrease in transmittance with a consequence of modifying the energy band gaps values between 2.79–3.32 eV. It was concluded that annealing influence optical transmittance and resistance of the film make the thin films potential for photovoltaic, and light sensing applications.

  13. PERBANDINGAN KINERJA ALGORITMA GENETIKA DAN SIMULATED ANNEALING UNTUK MASALAH MULTIPLE OBJECTIVE PADA PENJADWALAN FLOWSHOP

    Directory of Open Access Journals (Sweden)

    I Gede Agus Widyadana

    2002-01-01

    Full Text Available The research is focused on comparing Genetics algorithm and Simulated Annealing in the term of performa and processing time. The main purpose is to find out performance both of the algorithm to solve minimizing makespan and total flowtime in a particular flowshop system. Performances of the algorithms are found by simulating problems with variation of jobs and machines combination. The result show the Simulated Annealing is much better than the Genetics up to 90%. The Genetics, however, only had score in processing time, but the trend that plotted suggest that in problems with lots of jobs and lots of machines, the Simulated Annealing will run much faster than the Genetics. Abstract in Bahasa Indonesia : Penelitian ini difokuskan pada pembandingan algoritma Genetika dan Simulated Annealing ditinjau dari aspek performa dan waktu proses. Tujuannya adalah untuk melihat kemampuan dua algoritma tersebut untuk menyelesaikan problem-problem penjadwalan flow shop dengan kriteria minimasi makespan dan total flowtime. Kemampuan kedua algoritma tersebut dilihat dengan melakukan simulasi yang dilakukan pada kombinasi-kombinasi job dan mesin yang berbeda-beda. Hasil simulasi menunjukan algoritma Simulated Annealing lebih unggul dari algoritma Genetika hingga 90%, algoritma Genetika hanya unggul pada waktu proses saja, namun dengan tren waktu proses yang terbentuk, diyakini pada problem dengan kombinasi job dan mesin yang banyak, algoritma Simulated Annealing dapat lebih cepat daripada algoritma Genetika. Kata kunci: Algoritma Genetika, Simulated Annealing, flow shop, makespan, total flowtime.

  14. Irradiation, annealing, and reirradiation research in the ORNL heavy-section steel irradiation program

    International Nuclear Information System (INIS)

    Nanstad, R.K.; Iskander, S.K.; McCabe, D.E.; Sokolov, M.A.

    1997-01-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results from work performed as part of the Heavy-Section Steel Irradiation (HSSI) Program managed by Oak Ridge National Laboratory (ORNL) for the U.S. Nuclear Regulatory Commission. The HSSI Program focuses on annealing and re-embrittlement response of materials which are representative of those in commercial RPVs and which are considered to be radiation-sensitive. Experimental studies include (1) the annealing of materials in the existing inventory of previously irradiated materials, (2) reirradiation of previously irradiated/annealed materials in a collaborative program with the University of California, Santa Barbara (UCSB), (3) irradiation/annealing/reirradiation of U.S. and Russian materials in a cooperative program with the Russian Research Center-Kurchatov Institute (RRC-KI), (4) the design and fabrication of an irradiation/anneal/reirradiation capsule and facility for operation at the University of Michigan Ford Reactor, (5) the investigation of potential for irradiation-and/or thermal-induced temper embrittlement in heat-affected zones (HAZs) of RPV steels due to phosphorous segregation at grain boundaries, and (6) investigation of the relationship between Charpy impact toughness and fracture toughness under all conditions of irradiation, annealing, and reirradiation

  15. Effect of annealing temperature on the photoluminescence and scintillation properties of ZnO nanorods

    Science.gov (United States)

    Kurudirek, Sinem V.; Menkara, H.; Klein, Benjamin D. B.; Hertel, Nolan E.; Summers, Christopher J.

    2018-01-01

    The effect of the annealing to enhance the photoluminescence (PL) and scintillation properties, as determined by pulse height distribution of alpha particle irradiation, has been investigated for solution grown ZnO nanorods For this investigation the ZnO nanorod arrays were grown on glass for 22 h at 95 ∘C as a substrate using a solution based hydrothermal technique. The samples were first annealed for different times (30, 60, 90 and 120 min) at 300 ∘C and then at different temperatures (100 ∘C-600 ∘C) in order to determine the optimum annealing time and temperature, respectively. Before annealing, the ZnO nanorod arrays showed a broad yellow-orange visible and near-band gap UV emission peaks. After annealing in a forming gas atmosphere, the intensity of the sub-band gap PL was significantly reduced and the near-band gap PL emission intensity correspondingly increased (especially at temperatures higher than 100 ∘C). Based on the ratio of the peak intensity ratio before and after annealing, it was concluded that samples at 350 ∘C for 90 min resulted in the best near-band gap PL emission. Similarly, the analysis of the pulse height spectrum resulting from alpha particles revealed that ZnO nanorod arrays similarly annealed at 350 ∘C for 90 min exhibited the highest scintillation response.

  16. Enhanced bolometric properties of TiO2-x thin films by thermal annealing

    Science.gov (United States)

    Ashok Kumar Reddy, Y.; Shin, Young Bong; Kang, In-Ku; Lee, Hee Chul; Sreedhara Reddy, P.

    2015-07-01

    The effect of thermal annealing on the bolometric properties of TiO2-x films was investigated. The test-patterned TiO2-x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2-x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I-V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. Moreover, the annealed TiO2-x sample had a significantly low 1/f noise parameter (1.21 × 10-13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2-x film for a high-performance bolometric device.

  17. Accessing Forbidden Glass Regimes through High-Pressure Sub-Tg Annealing

    Science.gov (United States)

    Svenson, Mouritz N.; Mauro, John C.; Rzoska, Sylwester J.; Bockowski, Michal; Smedskjaer, Morten M.

    2017-04-01

    Density and hardness of glasses are known to increase upon both compression at the glass transition temperature (Tg) and ambient pressure sub-Tg annealing. However, a serial combination of the two methods does not result in higher density and hardness, since the effect of compression is countered by subsequent annealing and vice versa. In this study, we circumvent this by introducing a novel treatment protocol that enables the preparation of high-density, high-hardness bulk aluminosilicate glasses. This is done by first compressing a sodium-magnesium aluminosilicate glass at 1 GPa at Tg, followed by sub-Tg annealing in-situ at 1 GPa. Through density, hardness, and heat capacity measurements, we demonstrate that the effects of hot compression and sub-Tg annealing can be combined to access a “forbidden glass” regime that is inaccessible through thermal history or pressure history variation alone. We also study the relaxation behavior of the densified samples during subsequent ambient pressure sub-Tg annealing. Density and hardness are found to relax and approach their ambient condition values upon annealing, but the difference in relaxation time of density and hardness, which is usually observed for hot compressed glasses, vanishes for samples previously subjected to high-pressure sub-Tg annealing. This confirms the unique configurational state of these glasses.

  18. Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

    International Nuclear Information System (INIS)

    Tripathi, A.; Samajdar, I.; Nie, J.F.; Tewari, A.

    2016-01-01

    The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrasting behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.

  19. Cu(In,Ga)Se2 thin films annealed using a continuous wave Nd:YAG laser (λ0 = 532 nm): Effects of laser-annealing time

    Science.gov (United States)

    Yoo, Myoung Han; Ko, Pil Ju; Kim, Nam-Hoon; Lee, Hyun-Yong

    2017-12-01

    Preparation of Cu(In,Ga)Se2 (CIGS) thin films has continued to face problems related to the selenization of sputtered Cu-In-Ga precursors when using H2Se vapor in that the materials are highly toxic and the facilities extremely costly. Another obstacle facing the production of CIGS thin films has been the required annealing temperature, as it relates to the decomposition temperature of a typical flexible polymer substrate. A novel laser-annealing process for CIGS thin films, which does not involve the selenization process and which can be performed at a lower temperature, has been proposed. Following sputtering with a Cu0.9In0.7Ga0.3Se2 target, the laser-annealing of the CIGS thin film was performed using a continuous 532-nm Nd:YAG laser with an annealing time of 200 - 1000 s at a laser optical power of 2.75 W. CIGS chalcopyrite (112), (220/204), and (312/116) phases, with some weak diffraction peaks corresponding to the Cu-Se- or the In-Se-related phases, were successfully obtained for all the CIGS thin films that had been laser-annealed at 2.75 W. The lattice parameters, the d-spacing, the tetragonal distortion parameter, and the strain led to the crystallinity being worse and grain size being smaller at 600 s while better crystallinity was obtained at 200 and 800 s, which was closely related to the deviations from molecularity and stoichiometry, which were greatest at 600 s while the values exhibited near-stoichiometric compositions at 200 and 800 s. The band gaps of the laser-annealed CIGS thin films were within a range of 1.765 - 1.977 eV and depended on the internal stress. The mean absorbance of the laser-annealed CIGS thin films was within a range of 1.598 - 1.900, suggesting that approximately 97.47 - 98.74% of the incident photons in the visible spectral region were absorbed by this 400-nm film. The conductivity types exhibited the same deviations (Δ m > 0 and Δ s < 0) in all the laser-annealed CIGS thin films. After laser-annealing, the resistivity

  20. Annealing effect in structural and electrical properties of sputtered Mo thin film

    Energy Technology Data Exchange (ETDEWEB)

    Chelvanathan, P.; Zakaria, Z. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yusoff, Y. [Department of Electrical, Electronic and System Engineering, FKAB, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Akhtaruzzaman, M. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Alam, M.M. [Advanced Materials Research Chair, Chemistry Department, College of Sciences, King Saud University, Riyadh 11451 (Saudi Arabia); Alghoul, M.A.; Sopian, K. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Amin, N., E-mail: nowshadamin@yahoo.com [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Electrical, Electronic and System Engineering, FKAB, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Advanced Materials Research Chair, Chemistry Department, College of Sciences, King Saud University, Riyadh 11451 (Saudi Arabia)

    2015-04-15

    Highlights: • We deposited Mo thin film by DC-sputtering for solar cell back contact application. • We examined the changes in the film quality in terms of structural, and electrical upon vacuum thermal annealing. • Vacuum thermal annealing at different temperature changes the degree of preferred orientation of (1 1 0) and (2 1 1) significantly. • Correlation of structural and electrical parameters was carried out. - Abstract: In this study, the effects of vacuum annealing on the structural and electrical properties of DC-sputtered molybdenum (Mo) thin films have been investigated. Mo thin films were deposited by DC sputtering and subsequently subjected to vacuum annealing in a tube furnace from 350 to 500 °C. Films that were deposited with different temperatures showed good adhesion with soda lime glass substrate after “tape testing”. X-ray diffraction (XRD) spectra have indicated existence of (1 1 0) and (2 1 1) orientations. However, I(1 1 0)/I(2 1 1) peak intensity ratio decreased for all vacuum annealed Mo films compared to as-sputtered films indicating change of preferential orientation. This suggests vacuum annealing can be employed to tailor the Mo thin film atomic packing density of the plane parallel to the substrate. SEM images of surface morphology clearly show compact and dense triangular like grains for as-sputtered film, while annealed films at 350 °C, 400 °C and 450 °C indicate rice-like grains. Stony grains with less uniformity were detected for films annealed for 500 °C. Meanwhile, electrical resistivity is insensitive to the vacuum annealing condition as all films showed more or less same resistivity in the range of 3 × 10{sup −5}–6 × 10{sup −5} Ω cm.

  1. Effect of annealing temperature on structural, optical and electrical properties of hydrothermal assisted zinc oxide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, Guru Nisha; Sankar Ganesh, R.; Karthigeyan, A., E-mail: karthigeyan.a@ktr.srmuniv.ac.in

    2016-01-01

    Zinc oxide nanorods were grown employing a low cost hydrothermal method on microslide glass substrates pre-coated with ZnO seed layer. The as grown nanorods were annealed in air at 350 °C, 450 °C and 550 °C. The effect of annealing at different temperatures on morphology, structural, optical and electrical properties was investigated using field emission scanning electron microscopic, X-ray diffraction, UV–vis spectral, photoluminescence and electrical studies. The X-ray diffraction pattern of all the samples showed wurtzite structure preferentially oriented along the c-axis (0 0 2) direction. It was found that diameter of the nanorods increased with increasing of annealing temperature. The UV–vis absorption spectra showed a red shift from which it was inferred that the optical bandgap of the material decreases from 3.33 eV to 3.28 eV with increase in annealing temperature. Photoluminescence measurements showed increase in the UV emission intensity with respect to annealing temperature and also produced additional peaks attributed to defects and impurities. Annealing the ZnO nanorod structures at various temperatures evidently showed that the sample annealed at 550 °C acquired the lowest resistivity about 1.62 × 10{sup −4} Ω-cm. - Highlights: • ZnO nanorods were synthesized by hydrothermal method on microslide glass substrates. • Pre-deposited ZnO seeds were used. • Structural, optical and electrical properties of ZnO nanorods were studied. • Crystalline structure of ZnO nanorods was improved with increase in annealing temperature. • Resistivity decrease was observed with increase in the annealing temperature.

  2. Nd:YAG laser annealing investigation of screen-printed CIGS layer on PET: Layer annealing method for photovoltaic cell fabrication process

    KAUST Repository

    Alsaggaf, Ahmed

    2014-06-01

    Cu(In, Ga)Se2 (CIGS) ink was formulated from CIGS powder, polyvinyl butyral PVB, terpineol and polyester/polyamine co-polymeric dispersant KD-1. Thin films with different thicknesses were deposited on PET substrate using screen-printing followed by heat treatment using a Nd:YAG laser. The structure and morphology of the heated thin films were studied. The characterization of the CIGS powder, ink, and film was done using TGA, SEM, FIB, EDS, and XRD. TGA analysis shows that the CIGS ink is drying at 200 °C, which is well below the decomposition temperature of the PET substrate. It was observed by SEM that 20 pulses of 532nm and 60 mJ/cm2 Nd:YAG laser annealing causes atomic diffusion on the near surface area. Furthermore, FIB cross section images were utilized to monitor the effect of laser annealing in the depth of the layer. Laser annealing effects were compared to as deposited layer using XRD in reference to CIGS powder. The measurement shows that crystallinity of deposited CIGS is retained while EDS quantification and atomic ratio result in gradual loss of selenium as laser energy increases. The laser parameters were tuned in an effort to utilize laser annealing of screen-printed CIGS layer as a layer annealing method for solar cell fabrication process.

  3. Study of phosphorus implanted and annealed silicon by electrical measurements and ion channeling technique

    CERN Document Server

    Hadjersi, T; Zilabdi, M; Benazzouz, C

    2002-01-01

    We investigated the effect of annealing temperature on the electrical activation of phosphorus implanted into silicon. The measurements performed using spreading resistance, four-point probe and ion channeling techniques have allowed us to establish the existence of two domains of variation of the electrical activation (350-700 deg. C) and (800-1100 deg. C). The presence of reverse annealing and the annihilation of defects have been put in a prominent position in the first temperature range. It has been shown that in order to achieve a complete electrical activation, the annealing temperature must belong to the second domain (800-1100 deg. C).

  4. Synthesis of ZnO nanocrystals in sapphire by ion implantation and vacuum annealing

    Energy Technology Data Exchange (ETDEWEB)

    Marques, C. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Franco, N. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Alves, L.C. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Silva, R.C. da [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal) and Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Alves, E. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal) and Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal)]. E-mail: ealves@itn.pt; Safran, G. [Research Institute for Technical Physics and Materials Science, H-1525 Budapest (Hungary); McHargue, C.J. [University of Tennessee, Knoxville, TN 37996-0750 (United States)

    2007-04-15

    The synthesis of embedded ZnO nanoparticles in m-cut sapphire was achieved through high fluence Zn ion implantation, 0.9 x 10{sup 17} cm{sup -2} at room temperature, followed by annealing at 1000 deg. C in vacuum. In c-cut samples subjected to similar annealing conditions only buried precipitates of Zn form. TEM results in these samples show a high concentration of faceted precipitates distributed along the c-plane and the presence of Kirkendall voids distributed along the entire implanted region. In both cases a strong loss of Zn is observed upon annealing, which depends on the sapphire host orientation.

  5. Equipment, measurement technique and annealing of LiF (TLD-100) in TL-dosimetry

    International Nuclear Information System (INIS)

    Unhjem, J.F.

    1987-01-01

    Results of variations in reference light, dark current, TL-signal and total background signal during a read-out series of LiF (TLD-100) crystals are presented. Also two annealing procedures are compared. The results indicate a good signal-to-noise ratio, E(S)/σ, and that a new annealing procedure takes less time to carry out. Because of the time-saving effect and the high signal-to-noise ratio, the new annealing procedure can be recommended

  6. Effect of cold working and annealing on stress corrosion cracking of AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Yeon, Y.M.; Kwun, S.I.

    1983-01-01

    A study was made of the effects of cold working and annealing on the stress corrosion cracking of AISI 304 stainless steel in boiling 42% MgCl 2 solution. When the 60% or 76% of yield stress was applied, the resistance to SCC showed maximum at 30% of cold work. However, when the same load was applied to the annealed specimens after cold working, the resistance to SCC decreased abruptly at 675degC annealing. The fracture mode changed mode change mixed → intergranular → transgranular as the amount of cold work increased. (Author)

  7. Annealing effect in bulk heterojunction organic solar cells utilizing liquid crystalline phthalocyanine

    Science.gov (United States)

    Ohmori, Masashi; Fukui, Hitoshi; Dao, Quang-Duy; Kumada, Taishi; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2014-01-01

    The effect of annealing on bulk heterojunction solar cells utilizing the liquid crystalline phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2), fabricated using various solvents was studied. In the solar cells fabricated using chloroform, the power conversion efficiency was enhanced from 1.2 to 2.5% by thermal annealing at 75 °C, near the glass-transition temperature of the bulk heterojunction film. We discuss the effects of annealing on the photovoltaic properties by considering the exciton dissociation and carrier transport efficiencies obtained from photoluminescence spectra, X-ray diffraction measurement, and atomic force microscope observation.

  8. TiOx-based thin-film transistors prepared by femtosecond laser pre-annealing

    Science.gov (United States)

    Shan, Fei; Kim, Sung-Jin

    2018-02-01

    We report on thin-film transistors (TFTs) based on titanium oxide (TiOx) prepared using femtosecond laser pre-annealing for electrical application of n-type channel oxide transparent TFTs. Amorphous TFTs using TiOx semiconductors as an active layer have a low-temperature process and show remarkable electrical performance. And the femtosecond laser pre-annealing process has greater flexibility and development space for semiconductor production activity, with a fast preparation method. TFTs with a TiOx semiconductor pre-annealed via femtosecond laser at 3 W have a pinhole-free and smooth surface without crystal grains.

  9. Pd-based alloy nanoclusters in ion-implanted silica: Formation and stability under thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, G.; Cattaruzza, E.; De Marchi, G.; Gonella, F.; Mattei, G. E-mail: mattei@padova.infm.it; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C.; Calliari, I

    2002-05-01

    In this work we report on the formation and stability under thermal annealing of Pd-Cu and Pd-Ag alloy nanoclusters obtained by sequential ion implantation in silica. The role of the annealing atmosphere on the alloy cluster formation and stability is investigated. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions, in order to evidence the peculiar effect of the various metals in controlling the alloy evolution and/or decomposition.

  10. Resistance and magnetoresistance of annealed amorphous carbon films containing Fe3C nanograins

    International Nuclear Information System (INIS)

    Lee Yuhua; Han Taichun; Wur, C.-S.

    2004-01-01

    The temperature-dependent resistance and the field-dependent magnetoresistance were measured for films annealed at temperatures from 250 deg. C to 550 deg. C for a period of 60 min. Results of temperature-dependent resistance show electrical tunneling conductance in the films annealed at T a =250 deg. C and 350 deg. C only. The largest magnetoresistance ratio (MR) of 23% at temperature T=2 K was observed for T a =350 deg. C. The variations of both the temperature dependence of resistance and the magnetoresistance with the annealing temperature are discussed

  11. Proximity annealing of sulfur-implanted gallium arsenide using a strip heater

    International Nuclear Information System (INIS)

    Banerjee, S.; Baker, J.

    1985-01-01

    A graphite strip heater has been employed for rapid (-- 30 s) thermal annealing (RTA), at temperatures between 850 and 1150 0 C, of Cr-doped GaAs implanted with 120 keV 32 S + with doses between 10 13 and 10 15 cm -2 . In order to minimize the incongruent evaporation of As, proximity anneals were employed by protecting the implanted samples with GaAs cover pieces. RTA yields electrical activation and donor mobilities better than or comparable to furnace annealing, with less redistribution of the implanted S and background Cr. (author)

  12. Annealing temperature dependence of exchange bias in BiFeO3/CoFe bilayers

    Science.gov (United States)

    Yu, T.; Naganuma, H.; Wang, W. X.; Ando, Y.; Han, X. F.

    2012-04-01

    BiFeO3/CoFe bilayers with different BiFeO3 (BFO) crystalities were fabricated by chemical solution deposition and sputtering method. Exchange bias has been successfully induced in these bilayers by post-annealing. The annealing temperature dependence of exchange bias as well as coercivity was investigated. Two kinds of annealing temperature dependence behaviors were observed. It is found that, similar to the conventional antiferromagnet/ferromagnet system, the temperature dependence of exchange bias is dominated by direct interface coupling, and the crystality of BFO has no profound effect on exchange bias.

  13. Screening technique for loading pattern optimization by simulated annealing

    International Nuclear Information System (INIS)

    Park, Tong Kyu; Kim, Chang Hyo; Lee, Hyun Chul; Joo, Hyung Kook

    2005-01-01

    Lots of efforts have been devoted to developing the fuel assembly (FA) loading pattern (LP) optimization code using various optimization algorithms. Among them the simulated annealing (SA) algorithm appears very promising because of its robustness in the optimization calculations. However, SA algorithm has a major drawback of long computing time because it requires the neutronics evaluation of several tens of thousands of the trial LPs in the course of the optimization. In order to reduce computing time, a simple two-dimensional (2D) neutronics evaluation model has been used. Unfortunately, however, the final LP obtained from the 2D SA calculation often turns out to be unsatisfactory when it was evaluated by 3D neutronics evaluation model. A simple and straightforward way of resolving this problem would be to adopt 3D evaluation model instead of 2D model during the optimization procedure but this would take a long computing time. In this paper we propose a screening technique based on 2D evaluation model aimed at reducing computing time in SA calculation with 3D neutronics evaluation model

  14. Simulated Annealing Technique for Routing in a Rectangular Mesh Network

    Directory of Open Access Journals (Sweden)

    Noraziah Adzhar

    2014-01-01

    Full Text Available In the process of automatic design for printed circuit boards (PCBs, the phase following cell placement is routing. On the other hand, routing process is a notoriously difficult problem, and even the simplest routing problem which consists of a set of two-pin nets is known to be NP-complete. In this research, our routing region is first tessellated into a uniform Nx×Ny array of square cells. The ultimate goal for a routing problem is to achieve complete automatic routing with minimal need for any manual intervention. Therefore, shortest path for all connections needs to be established. While classical Dijkstra’s algorithm guarantees to find shortest path for a single net, each routed net will form obstacles for later paths. This will add complexities to route later nets and make its routing longer than the optimal path or sometimes impossible to complete. Today’s sequential routing often applies heuristic method to further refine the solution. Through this process, all nets will be rerouted in different order to improve the quality of routing. Because of this, we are motivated to apply simulated annealing, one of the metaheuristic methods to our routing model to produce better candidates of sequence.

  15. Dewetting of Epitaxial Silver Film on Silicon by Thermal Annealing

    Science.gov (United States)

    Sanders, Charlotte E.; Kellogg, Gary L.; Shih, C.-K.

    2013-03-01

    It has been shown that noble metals can grow epitaxially on semiconducting and insulating substrates, despite being a non-wetting system: low temperature deposition followed by room temperature annealing leads to atomically flat film morphology. However, the resulting metastable films are vulnerable to dewetting, which has limited their utility for applications under ambient conditions. The physics of this dewetting is of great interest but little explored. We report on an investigation of the dewetting of epitaxial Ag(111) films on Si(111) and (100). Low energy electron microscopy (LEEM) shows intriguing evolution in film morphology and crystallinity, even at temperatures below 100oC. On the basis of these findings, we can begin to draw compelling inferences about film-substrate interaction and the kinetics of dewetting. Financial support is from NSF, DGE-0549417 and DMR-0906025. This work was performed, in part, at the Center for Integrated Nanotechnologies, User Facility operated for the U.S. DOE Office of Science. Sandia National Lab is managed and operated by Sandia Corp., a subsidiary of Lockheed Martin Corp., for the U.S. DOE's National Nuclear Security Administration under DE-AC04-94AL85000.

  16. Ionization annealing of semiconductor crystals. Part two: the experiment

    Directory of Open Access Journals (Sweden)

    Garkavenko A. S.

    2014-12-01

    Full Text Available There is a conception that irradiation of semiconductor crystals with high energy electrons (300 keV results in a significant and irreversible deterioration of their electrical, optical and structural properties. Semiconductors are typically irradiated by low voltage electron accelerators with a continuous flow, the current density in such accelerators is 10–5—10–6 A/cm2, the energy — 0,3—1 MeV. All changes in the properties after such irradiation are resistant at room temperature, and marked properties recovery to baseline values is observed only after prolonged heating of the crystals to a high temperature. In contrast, the authors in their studies observe an improvement of the structural properties of semiconductor crystals (annealing of defects under irradiation with powerful (high current pulsed electron beams of high energy (E0 = 0,3–1 MeV, t = 0,1—10 ns, Ω = 1—10 Hz, j = 20—300 A/cm2. In their previous paper, the authors presented theoretical basis of this effect. This article describes an experimental study on the influence of high-current pulsed electron beams on the optical homogeneity of semiconductor GaAs and CdS crystals, confirming the theory put forward earlier.

  17. He+ and H+ microbeam damage, swelling and annealing in diamonds

    International Nuclear Information System (INIS)

    Dooley, S.P.; Jamieson, D.N.; Prawer, S.

    1992-01-01

    The effects of scanned 2 MeV He + and 1.4 MeV H + microbeam irradiation on unimplanted and P implanted diamond are discussed. Although diamond was found to be resistant to lattice defect production, it was found to swell very rapidly in comparison with other materials, giving rise to serious swelling induced dechanneling at scan edges at relatively low doses (10 17 /cm 2 for 2 MeV He + ). Microbeams annealed the damage due to a 1.5 μm deep Phosphorus implantation at a dose of 10 15 P + /cm 2 . The implantation damage was reduced at a dose of (1.6 x 10 17 /cm 2 ) by up to 21 % for 2 MeV He + irradiation, up to 16% for high flux 1.4 MeV H + irradiation and 12% for low flux H + irradiation. For the choice of analysis beam, all these beam effects were found to be most significant for He + microbeams, so H + microbeams should be used for analysis of diamond unless high depth resolution is required. 13 refs., 10 figs

  18. Finding a Hadamard matrix by simulated annealing of spin vectors

    Science.gov (United States)

    Bayu Suksmono, Andriyan

    2017-05-01

    Reformulation of a combinatorial problem into optimization of a statistical-mechanics system enables finding a better solution using heuristics derived from a physical process, such as by the simulated annealing (SA). In this paper, we present a Hadamard matrix (H-matrix) searching method based on the SA on an Ising model. By equivalence, an H-matrix can be converted into a seminormalized Hadamard (SH) matrix, whose first column is unit vector and the rest ones are vectors with equal number of -1 and +1 called SH-vectors. We define SH spin vectors as representation of the SH vectors, which play a similar role as the spins on Ising model. The topology of the lattice is generalized into a graph, whose edges represent orthogonality relationship among the SH spin vectors. Starting from a randomly generated quasi H-matrix Q, which is a matrix similar to the SH-matrix without imposing orthogonality, we perform the SA. The transitions of Q are conducted by random exchange of {+, -} spin-pair within the SH-spin vectors that follow the Metropolis update rule. Upon transition toward zeroth energy, the Q-matrix is evolved following a Markov chain toward an orthogonal matrix, at which the H-matrix is said to be found. We demonstrate the capability of the proposed method to find some low-order H-matrices, including the ones that cannot trivially be constructed by the Sylvester method.

  19. Concurrent laser welding and annealing exploiting robotically manipulated optical fibers

    Science.gov (United States)

    Abdullah, Hussein A.; Siddiqui, Rafiq A.

    2002-12-01

    Present investigation reports on the effects of incorporating pre- and post-heating on the mechanical properties of laser-welded joints, in normal air condition. Two common types of steels, i.e. mild steel, and stainless steel were welded with Lumonic's MS 830 Nd 3+:YAG laser machine, with an output capacity of 400 W. Due to the low integrated energy input required for laser welded joints, the welded region are often cooled too rapidly via conduction to the surrounding material and atmosphere, which leads to hardness discontinuities in the fusion and heat affected zone. The effects of in-process laser annealing on the mechanical properties and microstructure of laser-welded joints are important in any manufacturing operation. To improve the poor weld characteristics, this work investigates the use of automated dual-beam delivery system to implement a pre- or post-heating technique, simultaneously with the welding process. The results show that proper selection of the control parameters for the pre- or post-heating can reduce the hardness of the weld significantly and improve the welded joints mechanical properties, such as higher tensile strength and better durability.

  20. Enhanced Simulated Annealing for Solving Aggregate Production Planning

    Directory of Open Access Journals (Sweden)

    Mohd Rizam Abu Bakar

    2016-01-01

    Full Text Available Simulated annealing (SA has been an effective means that can address difficulties related to optimisation problems. SA is now a common discipline for research with several productive applications such as production planning. Due to the fact that aggregate production planning (APP is one of the most considerable problems in production planning, in this paper, we present multiobjective linear programming model for APP and optimised by SA. During the course of optimising for the APP problem, it uncovered that the capability of SA was inadequate and its performance was substandard, particularly for a sizable controlled APP problem with many decision variables and plenty of constraints. Since this algorithm works sequentially then the current state will generate only one in next state that will make the search slower and the drawback is that the search may fall in local minimum which represents the best solution in only part of the solution space. In order to enhance its performance and alleviate the deficiencies in the problem solving, a modified SA (MSA is proposed. We attempt to augment the search space by starting with N+1 solutions, instead of one solution. To analyse and investigate the operations of the MSA with the standard SA and harmony search (HS, the real performance of an industrial company and simulation are made for evaluation. The results show that, compared to SA and HS, MSA offers better quality solutions with regard to convergence and accuracy.

  1. Influence of Different Annealing Conditions on Optical and Electrical Properties of Sn Doped ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    LIU Tao

    2017-08-01

    Full Text Available Sn doped ZnO thin films(SZO was prepared on glasses by sol-gel method.The influence of six kinds of annealing conditions,including air annealing,low vacuum annealing,high vacuum annealing,N2 annealing,triple high vacuum annealing,cycle annealing on the crystal structure, optical and electrical properties of the SZO film was studied.The results show that all the SZO samples show preferential orientation along the c-axis.The SZO thin films has the optimum crystal structure and electrical property on the high vacuum annealing conditions.The minimum resistivity of the film is 5.4×10-2Ω·cm.The average visible transmittance of SZO thin film is above 85%.The photoluminescence peaks at 390nm and 440nm is observed in all the samples (the excitation wavelength is set at 325nm.The intensity of the peak at 440nm is enhanced significantly on air annealing,N2 annealing and low vacuum annealing.

  2. Effect of microwave annealing on electrical characteristics of TiN/Al/TiN/HfO2/Si MOS capacitors

    Science.gov (United States)

    Shih, Tzu-Lang; Su, Yin-Hsien; Kuo, Tai-Chen; Lee, Wen-Hsi; Current, Michael Ira

    2017-07-01

    In this letter, microwave annealing over a wide range of power (300-2700 W) in nitrogen ambient was performed on TiN/Al/TiN/HfO2/Si metal-oxide-semiconductor capacitors. Capacitors with rapid thermal annealing at 500 °C were also fabricated for comparison at the same wafer temperature measured during microwave annealing at 2700 W. For microwave annealed capacitors, key parameters such as equivalent oxide thickness, interface state density, oxide trapped charge, leakage current density, and breakdown voltage were all improved with increasing microwave annealing power. For the capacitor with rapid thermal annealing at 500 °C, diffusion of Al into TiN and growth of the interfacial oxide layer are detected, leading to the shift in flat-band voltage and increase in equivalent oxide thickness, respectively. The results further indicate that it is more effective to remove the charged traps by microwave annealing than by rapid thermal annealing, and the reduction in leakage current density after microwave annealing corresponds to the reduction in charge traps based on a trap-assisted tunneling model. With no trade-off relationship between the electrical characteristics and no undesired effect such as diffusion of species, microwave annealing demonstrates great potential for the post-metallization annealing process for the high-k/metal gate structure.

  3. Influence of annealing temperature on the microstructure and magnetic properties of Ni/NiO core-shell nanowires

    Science.gov (United States)

    Xiang, Wenfeng; Liu, Yuan; Yao, Jiangfeng; Sun, Rui

    2018-03-01

    Ni/NiO core-shell nanowires (NWs) were synthesized by thermal annealing of Ni NWs and variations in the microstructure, surface morphology, and magnetic properties of the NWs as a function of annealing temperature were investigated. The results showed that the grain size and crystal quality of NiO increased with an increasing annealing temperature. Specially, the effect of annealing temperature was much greater than annealing time for the formation of Ni/NiO NWs during the oxidization process. The total weight gain of the Ni/NiO NWs continuously increased when the annealing temperature was lower than 400 °C and the annealing time was more than 2 h; however, the weight gain of the Ni/NiO NWs was almost constant after annealing for 40 min when the annealing temperature was higher than 500 °C. The thorns on the surface of the Ni/NiO NWs gradually passivated and magnetic properties declined when the annealing temperature was increased from 300 °C to 400 °C. Smooth Ni/NiO NWs with no magnetic properties were prepared when the annealing temperature was over 500 °C. The detail study regarding the formation and evolution of Ni/NiO NWs is of considerable value and may provide useful information regarding the choice of post-treatment parameters for different applications of Ni/NiO NWs.

  4. Effect Of Low-Temperature Annealing On The Properties Of Ni-P Amorphous Alloys Deposited Via Electroless Plating

    Directory of Open Access Journals (Sweden)

    Zhao Guanlin

    2015-06-01

    Full Text Available Amorphous Ni-P alloys were prepared via electroless plating and annealing at 200°C at different times to obtain different microstructures. The effects of low-temperature annealing on the properties of amorphous Ni-P alloys were studied. The local atomic structure of the annealed amorphous Ni-P alloys was analyzed by calculating the atomic pair distribution function from their X-ray diffraction patterns. The results indicate that the properties of the annealed amorphous Ni-P alloys are closely related to the order atomic cluster size. However, these annealed Ni-P alloys maintained their amorphous structure at different annealing times. The variation in microhardness is in agreement with the change in cluster size. By contrast, the corrosion resistance of the annealed alloys in 3.5 wt% NaCl solution increases with the decrease in order cluster size.

  5. Dielectric Relaxation of La-Doped Zirconia Caused by Annealing Ambient

    Directory of Open Access Journals (Sweden)

    Werner M

    2011-01-01

    Full Text Available Abstract La-doped zirconia films, deposited by ALD at 300°C, were found to be amorphous with dielectric constants (k-values up to 19. A tetragonal or cubic phase was induced by post-deposition annealing (PDA at 900°C in both nitrogen and air. Higher k-values (~32 were measured following PDA in air, but not after PDA in nitrogen. However, a significant dielectric relaxation was observed in the air-annealed film, and this is attributed to the formation of nano-crystallites. The relaxation behavior was modeled using the Curie–von Schweidler (CS and Havriliak–Negami (HN relationships. The k-value of the as-deposited films clearly shows a mixed CS and HN dependence on frequency. The CS dependence vanished after annealing in air, while the HN dependence disappeared after annealing in nitrogen.

  6. Effect of cryo-rolling and annealing on microstructure and properties of commercially pure aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Rangaraju, Nikhil [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Raghuram, T. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Krishna, B. Vamsi [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)]. E-mail: vamsi23@yahoo.com; Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Venugopal, P. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2005-05-25

    Influence of cryo-rolling reduction and annealing of commercially pure (CP) Al is evaluated in four aspects: microstructure, mechanical properties, electrical conductivity and general corrosion. It is shown that by selecting optimal cryo-rolling reduction and subsequent annealing condition result in ultrafine grains in CP Al with good combination of high strength and ductility. Electrical conductivity of the cryo-rolled samples decreased due to increased number of the electron scattering centers (lattice defects and grain boundary area). However, optimization of cryo-rolling and annealing treatment could restore the conductivity coupled with high strength in CP Al. Corrosion behaviour of cryo-rolled CP Al improved after annealing treatment. High dissolution rate and low thermal stability of the ultrafine grain structure could override the anticipated advantage of uniform corrosion in ultrafine grain CP Al.

  7. Study on the process of radiation defects annealing in corundum crystals

    International Nuclear Information System (INIS)

    Abdukadyrova, I.Kh.; Vakhidov, Sh.A.; Khaimov-Mal'kov, V.Ya.

    1975-01-01

    The paper reports on the results of an investigation of the annealing of the colour centres that appear in samples of corundum during reactor irradiation and located in the near ultra-violet and visible portions of the spectrum. (author)

  8. An inexpensive electron beam annealing apparatus with line focus, made from a converted electron welding machine

    International Nuclear Information System (INIS)

    Krimmel, E.F.; Lutsch, AG.K.; Meyer, H.P.; Theron, S.B.K.

    1985-01-01

    Electron beam annealing has, after an active period of research, become an established technology in the production of semiconductor devices, since high quality restoration practically without out-diffusion, can be achieved. Many universities and research institutions cannot afford to purchase a dedicated electron beam annealing apparatus. In the following a conversion of an industrial electron beam welding apparatus into an annealing apparatus with line focus is described, which could easily be copied by interested institutions. A magnetic quadrupole-lens is described which converts the point into a line focus. Standard-TV deflections with a special generator circuit for the X and Y deflection are used. Electron currents of 4 to 5 mA cause silicon to melt (1415 deg C). Annealing results obtained with the apparatus are discussed. (author)

  9. Optimization of the GaAs et GaAs/Si annealing using halogen lamp flashes

    International Nuclear Information System (INIS)

    Blanck, H.

    1989-01-01

    The aim of the work is to check whether the flash annealing of GaAs and GaAs/Si, using halogen lamps, allows an improvement in the results obtained by usual methods. The electrical activation, defects behavior and results uniformity are studied. The results on the activation and diffusion of implanted impurities are shown to be equivalent to those obtained with classical annealing methods. However, residual impurities (or defects) diffusion phenomena are restrained by the flash annealing technique. The Hall effect cartographic measurements showed an improvement of the uniformity of the implanted coating surface resistance. Flash annealing is a suitable method for the Si activation in GaAs. It allows an improvement of the GaAs results obtained with standard techniques, as well as the formation, by means of ion implantation, of active zones in the GaAs/Si layers [fr

  10. Evolution of microstructure at hot band annealing of ferritic FeSi steels

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Jürgen, E-mail: juergen.schneider@t-online.de [Institute of Metal Forming, Technische Universität Bergakademie Freiberg, Bernhard-von Cotta-Str. 4, D-09596 Freiberg (Germany); Stahlzentrum Freiberg e.V., Leipziger Straße 34, D-09599 Freiberg (Germany); Li, Guangqiang [State Key Lab. of Refractories and Metallurgy, Wuhan University of Science and Technology, No. 947 Heping Avenue, Qingshan District, Wuhan 430081 (China); Franke, Armin [Stahlzentrum Freiberg e.V., Leipziger Straße 34, D-09599 Freiberg (Germany); Zhou, Bowen [State Key Lab. of Refractories and Metallurgy, Wuhan University of Science and Technology, No. 947 Heping Avenue, Qingshan District, Wuhan 430081 (China)

    2017-02-15

    The magnetic properties of the finally fabricated nonoriented FeSi steels critically depend on the microstructure and on the occurring crystallographic texture. The fabrication route comprises hot rolling, coiling and cooling, hot band annealing before cold rolling (optional), cold rolling and the final thermal treatment. As well known there is an interplay between the microstructure and texture during the various processing steps. For that reason, it is of interest to know more on the evolution of the microstructure at hot band annealing of hot band prepared in different ways. In this paper we will summarize our recent results on the evolution of microstructure during thermal annealing of hot band: thermal treatment following immediately the last pass of hot rolling or a hot band annealing as a separate processing step before cold rolling.

  11. Electric field assisted thermal annealing reorganization of graphene oxide/polystyrene latex films

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available Graphene/polymer films were prepared by casting water dispersion of graphene oxide (GO in the presence of polystyrene (PS latex particles. The samples were heated up to 180°C and exposed to an external electric voltage during their annealing. We observed that for the GO/PS films deposited before the electric field assisted thermal annealing the polymer latex was embedded in the graphene sheets, while the electric field assisted thermal annealing induces a phase separation with the enrichment of the PS phase above an underlying GO layer. For the films annealed under an external electric field we have also found that as the electric current passes through the GO film, GO could be recovered to reduced GO with decreased resistance.

  12. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... telecommunication. However, silicon clustering appears in the thin films when annealing above 1150 oC. Clustering is undesirable in waveguide materials because the localized variations of the refractive index associated with the clusters lead to Raleigh scattering, which can cause significant propagation loss...... in optical waveguides. This means that the annealing temperature must be high enough to break the N-H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 oC. The chemical composition of amorphous silicon-rich nitride has been...

  13. IGZO TFT-based circuit with tunable threshold voltage by laser annealing

    Science.gov (United States)

    Huang, Xiaoming; Yu, Guang; Wu, Chenfei

    2017-11-01

    In this work, a high-performance inverter based on amorphous indium-gallium-zinc oxide thin-film transistors (TFTs) has been fabricated, which consists of a driver TFT and a load TFT. The threshold voltage (Vth) of the load TFT can be tuned by applying an area-selective laser annealing. The transfer curve of the load TFT shows a parallel shift into the negative bias direction upon laser annealing. Based on x-ray photoelectron spectroscopy analyses, the negative Vth shift can be attributed to the increase of oxygen vacancy concentration within the device channel upon laser irradiation. Compared to the untreated inverter, the laser annealed inverter shows much improved switching characteristics, including a large output swing range which is close to full swing, as well as an enhanced output voltage gain. Furthermore, the dynamic performance of ring oscillator based on the laser-annealed inverter is improved.

  14. The role of Frenkel defect diffusion in dynamic annealing in ion-irradiated Si

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J. B.; Aji, L. B. Bayu; Martin, A. A.; Shin, S. J.; Shao, L.; Kucheyev, S. O.

    2017-01-06

    The formation of stable radiation damage in crystalline solids often proceeds via complex dynamic annealing processes, involving migration and interaction of ballistically-generated point defects. The dominant dynamic annealing processes, however, remain unknown even for crystalline Si. Here, we use a pulsed ion beam method to study defect dynamics in Si bombarded in the temperature range from -20 to 140 °C with 500 keV Ar ions. Results reveal a defect relaxation time constant of ~10–0.2 ms, which decreases monotonically with increasing temperature. The dynamic annealing rate shows an Arrhenius dependence with two well-defined activation energies of 73 ± 5 meV and 420 ± 10 meV, below and above 60 °C, respectively. Rate theory modeling, bench-marked against this data, suggests a crucial role of both vacancy and interstitial diffusion, with the dynamic annealing rate limited by the migration and interaction of vacancies.

  15. 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 microstru......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...... microstructure, the fraction of high angle boundaries was slightly lower than that in the as-rolled conditions. Recrystallization textures of both samples contained significant fractions of the rolling texture components. The fraction of the retained rolling texture was however greater in the strain-6.4 sample...

  16. Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This guide covers the general procedures to be considered for conducting an in-service thermal anneal of a light-water moderated nuclear reactor vessel and demonstrating the effectiveness of the procedure. The purpose of this in-service annealing (heat treatment) is to improve the mechanical properties, especially fracture toughness, of the reactor vessel materials previously degraded by neutron embrittlement. The improvement in mechanical properties generally is assessed using Charpy V-notch impact test results, or alternatively, fracture toughness test results or inferred toughness property changes from tensile, hardness, indentation, or other miniature specimen testing (1). 1.2 This guide is designed to accommodate the variable response of reactor-vessel materials in post-irradiation annealing at various temperatures and different time periods. Certain inherent limiting factors must be considered in developing an annealing procedure. These factors include system-design limitations; physical constrain...

  17. Relationship between beta radiation induced thermoluminescence and thermal annealing procedures in ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T. [ESIME-IPN, Culhuacan, 04430 Mexico D.F. (Mexico); Azorin, J.; Campero, A.; Velasquez, C. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C. [Physics Department, Rome University ' ' La Sapienza' ' , Rome (Italy)

    2004-07-01

    The influence of thermal treatment on the glow curve characteristics of undoped ZrO2 polycrystalline powder were studied in the range 700 to 1100 . The TL intensity of annealed ZrO2 powder, previously exposed to a given beta dose, submitted to different thermal treatments in the range from 700 to 1100 increases as the annealing temperature is increased. The TL glow curve of ZrO2 powder beta irradiated at absorbed doses up to 20 Gy exhibited a single peak centered at 200 . Furthermore, if the absorbed dose is increased up to 25 Gy the glow curve changes, appearing a second peak with its maximum centered at 250 . Then, it could be concluded that the TL response of ZrO2 powder is closely related to the annealing procedures and the creation of charge trapping centers corresponding to the 200 and 250 TL peaks depends on the annealing temperature. (Author)

  18. Effects of Solution Annealing Temperature on the Galvanic Corrosion Behavior of the Super Duplex Stainless Steels

    Science.gov (United States)

    Lee, Jun-Seob; Jeon, Soon-Hyeok; Park, Yong-Soo

    2013-02-01

    This study investigated the active dissolution of super duplex stainless steel (SDSS) at various solution annealing temperatures. The active dissolutions of the α-phase and γ-phase were compared, and the effects of the surface area ratio on the active dissolutions of both phases were investigated. There were two peaks in the active-passive transition region in the potentiodynamic test in the modified green-death solution. The two peaks changed as the solution annealing temperature was increased from 1050 to 1150 °C. The solution annealing temperature difference affected the critical anodic current densities. This provides useful information for determining the appropriate solution annealing temperature in the modified green-death solution for SDSS.

  19. Annealing Effect on Corrosion Behavior of the Beta-Quenched HANA Alloy

    International Nuclear Information System (INIS)

    Kim, Hyun Gil; Kim, Il Hyun; Choi, Byung Kwan; Park, Sang Yoon; Park, Jeong Yong; Jeong, Yong Hwan

    2009-01-01

    The advanced fuel cladding materials named as HANA cladding have been developed at KAERI for application of high burn-up and that cladding showed an improved performance in both in-pile and out-of-pile conditions. However, the cladding performance could be changed by the annealing conditions during the tube manufacturing process. Especially, the corrosion resistance is considerably sensitive to their microstructure which is determined by a manufacturing process in the high Nb-containing zirconium alloys. They reported that the corrosion properties of the Nb-containing Zr alloys were considerably affected by the microstructure conditions such as the Nb concentration in the matrix and the second phase types. Therefore, the corrosion behavior of HANA cladding having the high Nb could be considerably affected by the annealing time and temperatures. The purpose of this study is focused on the annealing effect of the beta quenched HANA alloy to obtain the optimum annealing conditions

  20. Influence of low-temperature annealing on InSb properties

    International Nuclear Information System (INIS)

    Tsitsina, N.P.; Fadeeva, A.P.; Vdovkina, E.E.; Baryshev, N.S.; Aver'yanov, I.S.

    1975-01-01

    Annealing at 200 deg C during 6 days does not cause inversion of conductivity in n-InSb, leads to the increase of the carrier concentration and the decrease of the specific resistance in samples both of n- and of p-type; these variations being more significant in the material of n-type. The existence of a level at a distance of 0.15-0.17 eV from the ceiling of the valency zone in non-annealed samples of InSb is confirmed. The level is of acceptor type and disappears with low-temperature annealing. The low-temperature annealing practically does not influence the lifetime in p-type samples and results in the 5-20-fold increase in the lifetime in n-type samples

  1. Post annealing performance evaluation of printable interdigital capacitive sensors by principal component analysis

    KAUST Repository

    Zia, Asif Iqbal

    2015-06-01

    The surface roughness of thin-film gold electrodes induces instability in impedance spectroscopy measurements of capacitive interdigital printable sensors. Post-fabrication thermodynamic annealing was carried out at temperatures ranging from 30 °C to 210 °C in a vacuum oven and the variation in surface morphology of thin-film gold electrodes was observed by scanning electron microscopy. Impedance spectra obtained at different temperatures were translated into equivalent circuit models by applying complex nonlinear least square curve-fitting algorithm. Principal component analysis was applied to deduce the classification of the parameters affected due to the annealing process and to evaluate the performance stability using mathematical model. Physics of the thermodynamic annealing was discussed based on the surface activation energies. The post anneal testing of the sensors validated the achieved stability in impedance measurement. © 2001-2012 IEEE.

  2. RBS channeling measurement of damage annealing in InAs/AlSb HEMT structures

    International Nuclear Information System (INIS)

    Hallén, Anders; Moschetti, Giuseppe

    2014-01-01

    Electrical isolation of InAs/AlSb high electron mobility transistors has been achieved by the ion implantation isolation technique. The multilayered structures are grown by molecular beam epitaxy on GaAs substrates. The optimal isolation is provided by damaging patterned areas by 100 keV Ar ions implanted at room temperature using fluence of 2 × 10 15 cm −2 , and then annealing the samples in 365 °C for 30 min. The damage build-up and annealing is studied by channeling Rutherford backscattering spectrometry (RBS) and compared to sheet resistance measurements. Only a low level of damage annealing can be seen in RBS for the post-implant annealed samples, but for Ar fluence higher than 2 × 10 14 cm −2 , a strong electrical resistivity increase can still be achieved

  3. RBS channeling measurement of damage annealing in InAs/AlSb HEMT structures

    Energy Technology Data Exchange (ETDEWEB)

    Hallén, Anders, E-mail: ahallen@kth.se [KTH Royal Institute of Technology, ICT, P.O. Box Electrum 229, SE 164 40 Kista (Sweden); Moschetti, Giuseppe [Chalmers University of Technology, Microtechnology and Nanoscience-MC2, SE-412 96 Gothenburg (Sweden)

    2014-08-01

    Electrical isolation of InAs/AlSb high electron mobility transistors has been achieved by the ion implantation isolation technique. The multilayered structures are grown by molecular beam epitaxy on GaAs substrates. The optimal isolation is provided by damaging patterned areas by 100 keV Ar ions implanted at room temperature using fluence of 2 × 10{sup 15} cm{sup −2}, and then annealing the samples in 365 °C for 30 min. The damage build-up and annealing is studied by channeling Rutherford backscattering spectrometry (RBS) and compared to sheet resistance measurements. Only a low level of damage annealing can be seen in RBS for the post-implant annealed samples, but for Ar fluence higher than 2 × 10{sup 14} cm{sup −2}, a strong electrical resistivity increase can still be achieved.

  4. Development of a supplemental surveillance program for reactor pressure vessel thermal annealing

    International Nuclear Information System (INIS)

    Server, W.L.; Rosinski, S.T.

    1997-01-01

    The technical decision to thermally anneal a nuclear reactor pressure vessel (RPV) depends upon the level of embrittlement in the RPV steels, the amount of recovery of fracture toughness properties expected from the anneal, and the rate of re-embrittlement after the vessel is placed back into service. The recovery of Charpy impact toughness properties after annealing can be estimated initially by using a recovery model developed using experimental measurements of recovery (such as that developed by Eason et al. for U.S. vessel materials). However, actual validation measurements on plant-specific archived vessel materials (hopefully in the existing surveillance program) are needed; otherwise, irradiated surrogate materials, essentially the same as the RPV steels or bounding in expected behavior, must be utilized. The efficient use of any of these materials requires a supplemental surveillance program focused at both recovery and reirradiation embrittlement. Reconstituted Charpy specimens and new surveillance capsules will most likely be needed as part of this supplemental surveillance program. A new version of ASTM E 509 has recently been approved which provides guidance on thermal annealing in general and specifically for the development of an annealing supplemental surveillance program. The post-anneal re-embrittlement properties are crucial for continued plant operation, and the use of a re-embrittlement model, such as the lateral shift approach, may be overly conservative. This paper illustrates the new ASTM E 509 Standard Guide methodology for an annealing supplemental surveillance program. As an example, the proposed program for the Palisades RPV beltline steels is presented which covers the time from annealing to the end of operating license and beyond, if license renewal is pursued. The Palisades nuclear power plant RPV was planned to be annealed in 1998, but that plant is currently being re-evaluated. The proposed anneal was planned to be conducted at a

  5. Special Features of Induction Annealing of Friction Stir Welded Joints of Medium-Alloy Steels

    Science.gov (United States)

    Priymak, E. Yu.; Stepanchukova, A. V.; Bashirova, E. V.; Fot, A. P.; Firsova, N. V.

    2018-01-01

    Welded joints of medium-alloy steels XJY750 and 40KhN2MA are studied in the initial condition and after different variants of annealing. Special features of the phase transformations occurring in the welded steels are determined. Optimum modes of annealing are recommended for the studied welded joints of drill pipes, which provide a high level of mechanical properties including the case of impact loading.

  6. [Effect of annealing pressure on P3HT : PCBM nanoscale morphology and photovoltaic properties].

    Science.gov (United States)

    Li, Chang; Xue, Wei; Zhang, Ting; Zhao, Su-ling

    2015-01-01

    The considerable performance enhancement of P3HT-based solar cell after thermal annealing can be attributed to the thermodynamically driven partial crystallization and phase segregation of each component. In the present work, thermal annealing was executed by delivering P3HT : PCBM blend films onto the preheated susceptor in a PECVD chamber filled with high purity nitrogen gas. The pressure of inner chamber could be set steadily and precisely in the range of 1 to 1 850 mTorr at 150 °C. It was found that the phase segregation scale of two components was tuned to a certain extent by varying the annealing pressure, whereas the polymer crystallinity was slightly affected. According to the pressure settings, polymer solar cells (PSCs) were fabricated in the following structure: ITO/PEDOT : PSS/P3HT : PCBM/Al. All of the device parameters exhibited the similar trend--an initial increase followed by a decrease, and reached a peak at 1500 mTorr with successive increase in annealing setting pressure. PSC annealed under 1 500 mTorr shows overall high performances with the power conversion efficiency up to 3. 56%. The UV-Vis absorption spectra of annealed blend films shows that the vibronic absorption peaks (shoulders) at 510, 550 and 600 nm became more pronounced under higher setting pressure, which is attributed to better crystalline P3HT with increased π-π stacking of polymer molecules. The AFM results further suggest that high annealing pressure (>1000 mTorr) promoted the domain formations of P3HT or PCBM; moreover, a moderate phase segregation, as a result of an appropriate annealing pressure (1500 mTorr), facilitates polymer crystallization which ensures the high charge (hole) mobility and consequently increased short-circuit current and fill factor.

  7. Modification of n-Si Characteristics by Annealing and Cooling at Different Rates

    Directory of Open Access Journals (Sweden)

    Subhi K. Salih

    2003-01-01

    for samples annealed at lower than 550°C. For samples annealed at higher temperatures, quenching gave better dark-current density vs. potential plots. SEM measurements showed parallel results to these findings. Enhanced surface textures were observed for slowly cooled wafers from temperatures below 550°C. Samples quenched from temperatures above 550°C showed better surfaces than slowly cooled counterparts.

  8. Thermal Annealing induced relaxation of compressive strain in porous GaN structures

    KAUST Repository

    Ben Slimane, Ahmed

    2012-01-01

    The effect of annealing on strain relaxation in porous GaN fabricated using electroless chemical etching is presented. The Raman shift of 1 cm-1 in phonon frequency of annealed porous GaN with respect to as-grown GaN corresponds to a relaxation of compressive strain by 0.41 ± 0.04 GPa. The strain relief promises a marked reduction in threading dislocation for subsequent epitaxial growth.

  9. Raman spectroscopy for characterization of annealing of ion-implanted InP

    International Nuclear Information System (INIS)

    Myers, D.R.; Gourley, P.L.; Vaidyanathan, K.V.; Dunlap, H.L.

    1983-01-01

    Raman spectroscopy has been used as a noncontacting, nondestructive tool to evaluate the properties of Si + - and Be + implanted InP samples annealed at temperatures ranging from 600 to 750C using phospho-silicate glass (PSG) as the encapsulant. Carrier activation, carrier mobility and recovery of damage as a function of anneal temperature obtained from analysis of Raman data agree very well with independent electrical measurements. (author)

  10. Effect of annealing on nanostructure and magnetic properties of Zr2Co11 material

    International Nuclear Information System (INIS)

    Zhang, W.Y.; Li, X.Z.; Valloppilly, S.; Skomski, R.; Sellmyer, D.J.

    2014-01-01

    Highlights: • Zr–Co alloy ribbons consist of the single phase with the rhombohedral structure. • Annealing decreases structural disorder's density, thus greatly increases coercivity. • A record value (9.7 kOe) of coercivity has been achieved in annealed Zr 2 Co 11 alloys. • Zr 2 Co 11 has potential for fabricating rare-earth-free hard magnetic nanocomposites. - Abstract: Single-phase Zr 2 Co 11 nanomagnetic materials with high coercivity have been fabricated by melt spinning with subsequent annealing under Ar, N 2 , and vaccum. Annealing coarsens the grains and decreases the density of defects, leading to intergrain decoupling action and the enhancement of the magnetocrystalline anisotropy field of the hard magnetic phase. Therefore, coercivity increases 44.7% from 6.7 kOe for the as-spun to 9.7 kOe for the annealed which is the highest among Zr–Co alloys so far. The results show that the magnetic-hardening mechanism is primarily dominated by domain-wall pinning. In addition, annealing clearly increases the saturation magnetization. The above results indicate that Zr 2 Co 11 has potential for fabricating rare-earth-free permanent-magnet nanocomposites

  11. Improved luminescence properties of nanocrystalline silicon based electroluminescent device by annealing

    International Nuclear Information System (INIS)

    Sato, Keisuke; Hirakuri, Kenji

    2006-01-01

    We report an annealing effect on electrical and luminescence properties of a red electroluminescent device consisting of nanocrystalline silicon (nc-Si). The red luminescence was generated by flowing the forward current into the device at a low threshold direct current (DC) forward voltage with a rise of annealing temperature up to 500 deg. C. Moreover, the luminescence of the device annealed at 500 deg. C was more intense than that of the device annealed at 200 deg. C or less under the same forward current density, because of the injection of a large quantity of carriers to the radiative recombination centers at the nc-Si surface vicinity. These were attained by a low resistivity of indium tin oxide (ITO) electrode and good contact at the ITO electrode/luminous layer interface region by the annealing treatment. The above results indicated that the annealing treatment of the device is effective for the realization of high luminance due to the improvement in the injection efficiency of carriers to the radiative recombination centers

  12. Luminescence and structural properties of ZnO thin films annealing in air

    Energy Technology Data Exchange (ETDEWEB)

    Baca, R; Martinez, J [Centro de Investigacion de Dispositivos Semiconductores, BUAP, Puebla, Pue. C.P. 72570 (Mexico); Esparza, A [Centro de Ciencias Aplicadas y Desarrollo de TecnologIa - UNAM. C.P. 04510, Mexico D.F (Mexico); Kryshtab, T [Departamento de Ciencias de Materiales, ESFM - IPN, Mexico D.F (Mexico); Juarez, G; Solache, H; Andraca, J; Pena, R, E-mail: rbaca02006@yahoo.com.mx

    2010-02-15

    All ZnO thin films deposited on (001) silicon substrates by DC reactive magnetron sputtering were annealed in air atmosphere with different times at 800deg. C. The samples were studied by X-ray diffraction technique (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD investigation showed that ZnO phase was hexagonal wurtzite structure growing along the (002) direction. The as grown ZnO films presented macrostrain and microstrain caused a shift of the line diffraction (002) and a broadening respectively. However after 1 hour annealing these strains disappear. The grain size of ZnO films increased with an increase of annealing time. The as-deposited reactive sputtering ZnO films resulted semi-insulating with poor PL response. After high temperature annealing in air, the crystallinity and the PL response considerably improved, but their semi-insulating property also increased. The PL spectra of the annealed samples showed well defined transitions close to the near-band-edge and a wide visible deep-level band emission (430-640 nm). The main interest of this work was to enhance the PL response and to identify the origin of deep-level luminescence bands. The AFM, PL and XRD results indicated that the ZnO films annealing have potential applications in optoelectronic devices.

  13. SANS examination of irradiated RPV steel welds during in-situ annealing

    Energy Technology Data Exchange (ETDEWEB)

    Boothby, R.M. [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Hyde, J.M., E-mail: jonathan.m.hyde@nnl.co.uk [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Swan, H. [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Parfitt, D.; Wilford, K. [Rolls-Royce plc, P.O. Box 2000, Derby DE21 7XX (United Kingdom); Lindner, P. [Institut Laue-Langevin, 71 avenue des Martyrs, CS20156, 38042 Grenoble CEDEX 9 (France)

    2015-06-15

    An in-situ annealing experiment was performed using SANS measurements to examine the distribution and thermal stability of irradiation-induced solute clusters in RPV steel welds. Samples were sequentially annealed for 30 min at ∼50 °C intervals in the temperature range 295–497 °C. A methodology was developed to correct the observed data to allow for increased thermal diffuse scattering during annealing which enabled analysis of the changes in coherent scattering in isolation. Results for a low-Ni weld irradiated at low temperature showed apparent decreases in the volume fraction of solute clusters during annealing. However the cluster size was unaffected and these results could have arisen from reduced scattering contrast due to compositional changes, rather than cluster dissolution. A similarly irradiated high-Ni weld exhibited cluster coarsening at high annealing temperatures. Samples of both welds irradiated at a higher temperature were relatively unaffected by annealing except at high temperatures where some shrinkage, indicative of cluster dissolution, occurred.

  14. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    International Nuclear Information System (INIS)

    Ortega, Y.; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R.

    2008-01-01

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T ≤ 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process

  15. Effect of Annealing on Properties of Carbonaceous Materials. Part II: Porosity and Pore Geometry

    Science.gov (United States)

    Xing, Xing; Zhang, Guangqing; Dell'Amico, Mark; Ciezki, George; Meng, Qingbo; Ostrovski, Oleg

    2013-08-01

    The pore structure of carbonaceous materials was studied using image analysis. The effect of annealing on the porosity and pore geometry of cokes, chars, and pyrolyzed coals (laboratory chars) was examined in the temperature range of 973 K to 1773 K (700 °C to 1500 °C). The porosity of chars and pyrolyzed coals significantly increased during annealing at temperatures below 1373 K (1100 °C) due to volatile matter release. Further increasing of the annealing temperature from 1373 K to 1773 K (1100 °C to 1500 °C) caused marginal porosity evolution. The porosity of cokes was not affected by annealing at temperatures below 1573 K (1300 °C) and slightly increased in the temperature range 1573 to 1773 K (1300 °C to 1500 °C). The increase in the porosity of chars and pyrolyzed coals during annealing at temperatures 1373 K to 1773 K (1100 °C to 1500 °C), and cokes at 1573 K to 1773 K (1300 °C to 1500 °C), was a result of reactions with oxides of their mineral phases. Annealing had a marginal effect on the pore shape (Feret ratio) of carbonaceous materials, but enlarged the pore size of chars and pyrolyzed coals and decreased their pore density.

  16. Photoluminescent properties of silicon carbide and porous silicon carbide after annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Hwan; Lee, Seung-Koo [Department of Chemistry, Kongju National University, Kongju 314-701 (Korea, Republic of); Jeon, Ki-Seok, E-mail: ksjeon@kongju.ac.kr [Fusion Biotechnology Research Center, KRICT, Daejeon 305-600 (Korea, Republic of)

    2009-02-01

    Photoluminescent (PL) p-type 6H porous silicon carbides (PSCs), which showed a strong blue-green photoluminescence band centered at approximately 490 nm, were annealed in Ar and vacuum conditions. The morphological, optical, and chemical states after annealing are reported on electrochemically etched SiC semiconductors. The thermal treatments in the Ar and vacuum environments showed different trends in the PL spectra of the PSC. In particular, in the case of annealing in a vacuum, the PL spectra showed both a weak red PL peak near 630 nm and a relatively intense PL peak at around 430 nm in the violet region. SEM images showed that the etched surface had spherical nanostructures, mesostructures, and islands. With increasing annealing temperature it changes all spherical nanostructures. The average pore size observed at the surface of the PSC before annealing was of the order of approximately 10 nm. In order to investigate the surface of a series of samples in detail, both the detection of a particular chemical species and the electronic environments at the surface are examined using X-ray photoelectron spectroscopy (XPS). The chemical states from each XPS spectrum depend differently before and after annealing the surface at various temperatures. From these results, the PL spectra could be attributed not only to the quantum size effects but also to the oxide state.

  17. Photoluminescent properties of silicon carbide and porous silicon carbide after annealing

    International Nuclear Information System (INIS)

    Lee, Ki-Hwan; Lee, Seung-Koo; Jeon, Ki-Seok

    2009-01-01

    Photoluminescent (PL) p-type 6H porous silicon carbides (PSCs), which showed a strong blue-green photoluminescence band centered at approximately 490 nm, were annealed in Ar and vacuum conditions. The morphological, optical, and chemical states after annealing are reported on electrochemically etched SiC semiconductors. The thermal treatments in the Ar and vacuum environments showed different trends in the PL spectra of the PSC. In particular, in the case of annealing in a vacuum, the PL spectra showed both a weak red PL peak near 630 nm and a relatively intense PL peak at around 430 nm in the violet region. SEM images showed that the etched surface had spherical nanostructures, mesostructures, and islands. With increasing annealing temperature it changes all spherical nanostructures. The average pore size observed at the surface of the PSC before annealing was of the order of approximately 10 nm. In order to investigate the surface of a series of samples in detail, both the detection of a particular chemical species and the electronic environments at the surface are examined using X-ray photoelectron spectroscopy (XPS). The chemical states from each XPS spectrum depend differently before and after annealing the surface at various temperatures. From these results, the PL spectra could be attributed not only to the quantum size effects but also to the oxide state.

  18. Thermal annealing recovery of fracture toughness in HT9 steel after irradiation to high doses

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang, E-mail: byunts@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Baek, Jong-Hyuk [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Anderoglu, Osman; Maloy, Stuart A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Toloczko, Mychailo B. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2014-06-01

    The HT9 ferritic/martensitic steel with a nominal chemistry of Fe(bal.)12%Cr1%MoVW has been used as a primary core material for fast fission reactors such as FFTF because of its high resistance to radiation-induced swelling and embrittlement. Both static and dynamic fracture test results have shown that the HT9 steel can become brittle when it is exposed to high dose irradiation at a relatively low temperature (<430 °C). This article aims at a comprehensive discussion on the thermal annealing recovery of fracture toughness in the HT9 steel after irradiation up to 3148 dpa at 378504 °C. A specimen reuse technique has been established and applied to this study: the fracture specimens were tested Charpy specimens or broken halves of Charpy bars (13 × 3 × 4 mm). The post-anneal fracture test results indicated that much of the radiation-induced damage can be recovered by a simple thermal annealing schedule: the fracture toughness was incompletely recovered by 550 °C annealing, while nearly complete or complete recovery occurred after 650 °C annealing. This indicates that thermal annealing is a feasible damage mitigation technique for the reactor components made of HT9 steel. The partial recovery is probably due to the non-removable microstructural damages such as void or gas bubble formation, elemental segregation and precipitation.

  19. Anomalous annealing of floating gate errors due to heavy ion irradiation

    Science.gov (United States)

    Yin, Yanan; Liu, Jie; Sun, Youmei; Hou, Mingdong; Liu, Tianqi; Ye, Bing; Ji, Qinggang; Luo, Jie; Zhao, Peixiong

    2018-03-01

    Using the heavy ions provided by the Heavy Ion Research Facility in Lanzhou (HIRFL), the annealing of heavy-ion induced floating gate (FG) errors in 34 nm and 25 nm NAND Flash memories has been studied. The single event upset (SEU) cross section of FG and the evolution of the errors after irradiation depending on the ion linear energy transfer (LET) values, data pattern and feature size of the device are presented. Different rates of annealing for different ion LET and different pattern are observed in 34 nm and 25 nm memories. The variation of the percentage of different error patterns in 34 nm and 25 nm memories with annealing time shows that the annealing of FG errors induced by heavy-ion in memories will mainly take place in the cells directly hit under low LET ion exposure and other cells affected by heavy ions when the ion LET is higher. The influence of Multiple Cell Upsets (MCUs) on the annealing of FG errors is analyzed. MCUs with high error multiplicity which account for the majority of the errors can induce a large percentage of annealed errors.

  20. Luminescence and structural properties of ZnO thin films annealing in air

    Science.gov (United States)

    Baca, R.; Juárez, G.; Solache, H.; Andraca, J.; Martinez, J.; Esparza, A.; Kryshtab, T.; Peña, R.

    2010-02-01

    All ZnO thin films deposited on (001) silicon substrates by DC reactive magnetron sputtering were annealed in air atmosphere with different times at 800°C. The samples were studied by X-ray diffraction technique (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD investigation showed that ZnO phase was hexagonal wurtzite structure growing along the (002) direction. The as grown ZnO films presented macrostrain and microstrain caused a shift of the line diffraction (002) and a broadening respectively. However after 1 hour annealing these strains disappear. The grain size of ZnO films increased with an increase of annealing time. The as-deposited reactive sputtering ZnO films resulted semi-insulating with poor PL response. After high temperature annealing in air, the crystallinity and the PL response considerably improved, but their semi-insulating property also increased. The PL spectra of the annealed samples showed well defined transitions close to the near-band-edge and a wide visible deep-level band emission (430-640 nm). The main interest of this work was to enhance the PL response and to identify the origin of deep-level luminescence bands. The AFM, PL and XRD results indicated that the ZnO films annealing have potential applications in optoelectronic devices.

  1. Chemical Annealing of Zinc Tetraphenylporphyrin Films: Effects on Film Morphology and Organic Photovoltaic Performance

    KAUST Repository

    Trinh, Cong

    2012-07-10

    We present a chemical annealing process for organic thin films. In this process, a thin film of a molecular material, such as zinc tetraphenylporphyrin (ZnTPP), is exposed to a vapor of nitrogen-based ligand (e.g., pyrazine, pz, and triazine, tz), forming a film composed of the metal-ligand complex. Fast and quantitative formation of the complex leads to marked changes in the morphology and optical properties of the film. X-ray diffraction studies show that the chemical annealing process converts amorphous ZnTPP films to crystalline ZnTPP•ligand films, whose porphryin planes lie nearly parallel to the substrate (average deviation is 8° for the ZnTPP•pz film). Organic solar cells were prepared with ZnTPP donor and C 60 acceptor layers. Devices were prepared with and without chemical annealing of the ZnTPP layer with a pyrazine ligand. The devices with chemically annealed ZnTPP donor layer show an increase in short-circuit current (J SC) and fill factor (FF) relative to analogous unannealed devices, presumably because of enhanced exciton diffusion length and improved charge conductivity. The open circuit voltages (V OC) of the chemically annealed devices are lower than their unannealed counterpart because of enhanced polaron pair recombination at the donor/acceptor heterojunction. A net improvement of 5-20% in efficiency has been achieved, after chemical annealing of ZnTPP films with pyrazine. © 2012 American Chemical Society.

  2. Development of fast heating electron beam annealing setup for ultra high vacuum chamber.

    Science.gov (United States)

    Das, Sadhan Chandra; Majumdar, Abhijit; Katiyal, Sumant; Shripathi, T; Hippler, R

    2014-02-01

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10(-6) mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  3. Annealing dependent evolution of columnar nanostructures in RF magnetron sputtered PTFE films for hydrophobic applications

    Science.gov (United States)

    Tripathi, S.; De, Rajnarayan; Maidul Haque, S.; Divakar Rao, K.; Misal, J. S.; Prathap, C.; Das, S. C.; Patidar, Manju M.; Ganesan, V.; Sahoo, N. K.

    2018-01-01

    Present communication focuses on a relatively less explored direction of producing rough polytetrafluoroethylene (PTFE) surfaces for possible hydrophobic applications. The experiments were carried out to make rough PTFE films without losing much of the transmission, which is an important factor while designing futuristic solar cell protection covers. After annealing temperature optimization, as grown RF magnetron sputtered PTFE films (prepared at 160 W RF power) were subjected to vacuum annealing at 200 °C for different time durations ranging from 1 to 4 h. The films show morphological evolution exhibiting formation and growth of columnar nanostructures that are responsible for roughening of the films due to annealing induced molecular migration and rearrangement. In agreement with this, qualitative analysis of corresponding x-ray reflectivity data shows modification in film thickness, which may again be attributed to the growth of columns at the expense of the atoms of remaining film molecules. However, the observations reveal that the film annealed at 200 °C for 2 h gives a combination of patterned columnar structures and reasonable transmission of >85% (in 500-1000 nm wavelength range), both of which are deteriorated when the films are annealed either at high temperature beyond 200 °C or for long durations >3 h. In addition, attenuated total reflection-Fourier transform infrared spectroscopy results reveal that the molecular bonds remain intact upon annealing at any temperature within the studied range indicating the stable nature of the films.

  4. Tailoring the magnetic properties and magnetorheological behavior of spinel nanocrystalline cobalt ferrite by varying annealing temperature.

    Science.gov (United States)

    Sedlacik, Michal; Pavlinek, Vladimir; Peer, Petra; Filip, Petr

    2014-05-14

    Magnetic nanoparticles of spinel nanocrystalline cobalt ferrite were synthesized via the sol-gel method and subsequent annealing. The influence of the annealing temperature on the structure, magnetic properties, and magnetorheological effect was investigated. The finite crystallite size of the particles, determined by X-ray diffraction and the particle size observed via transmission electron microscopy, increased with the annealing temperature. The magnetic properties observed via a vibrating sample magnetometer showed that an increase in the annealing temperature leads to the increase in the magnetization saturation and, in contrast, a decrease in the coercivity. The effect of annealing on the magnetic properties of ferrite particles has been explained by the recrystallization process at high temperatures. This resulted in grain size growth and a decrease in an imposed stress relating to defects in the crystal lattice structure of the nanoparticles. The magnetorheological characteristics of suspensions of ferrite particles in silicone oil were measured using a rotational rheometer equipped with a magnetic field generator in both steady shear and small-strain oscillatory regimes. The magnetorheological performance expressed as a relative increase in the magnetoviscosity appeared to be significantly higher for suspensions of particles annealed at 1000 °C.

  5. Directional annealing studies on rapidly solidified Sm–Co–Nb–C alloys

    International Nuclear Information System (INIS)

    Jayaraman, T.V.; Shield, J.E.

    2012-01-01

    In this paper, a process that develops texture in nanocrystalline permanent magnet alloys is presented. An originally isotropic material is passed through a high up-temperature gradient, inducing directional grain growth. Texture development by directional annealing of melt-spun Sm 12 Co 88 , (Sm 12 Co 88 ) 99 Nb 1 , (Sm 12 Co 88 ) 99 C 1 , and (Sm 12 Co 88 ) 98 Nb 1 C 1 alloys was examined. Samples directionally annealed were compared with conventionally annealed samples. Strong (0 0 6) in-plane texture was observed by X-ray diffraction in Sm 12 Co 88 and (Sm 12 Co 88 ) 99 Nb 1 alloys and the anisotropy was corroborated by magnetic measurements (magnetic texture ∼20–53%). Directional annealing produced only slight texture in the (Sm 12 Co 88 ) 99 C 1 and (Sm 12 Co 88 ) 98 Nb 1 C 1 alloys. The development of texture is critically dependent on annealing temperature, the up-temperature gradient, translational velocity, and alloy composition. The activation energy for anisotropic grain growth was estimated to be ∼28 and ∼42 kJ mol −1 for Sm 12 Co 88 and (Sm 12 Co 88 ) 99 Nb 1 , respectively. These results indicate that directional annealing as a route to texture development in nanocrystalline permanent magnet alloys is a feasible process.

  6. Microwave Synthesized ZnO Nanorod Arrays for UV Sensors: A Seed Layer Annealing Temperature Study

    Directory of Open Access Journals (Sweden)

    Ana Pimentel

    2016-04-01

    Full Text Available The present work reports the influence of zinc oxide (ZnO seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was produced using the spin-coating method and several annealing temperatures, ranging from 100 to 500 °C, have been tested. X-ray diffraction (XRD, scanning electron microscopy (SEM, atomic force microscopy (AFM and spectrophotometry measurements have been used to investigate the structure, morphology, and optical properties variations of the produced ZnO nanorod arrays regarding the seed layer annealing temperatures employed. After the growth of ZnO nanorod arrays, the whole structure was tested as UV sensors, showing an increase in the sensitivity with the increase of seed layer annealing temperature. The UV sensor response of ZnO nanorod arrays produced with the seed layer annealed temperature of 500 °C was 50 times superior to the ones produced with a seed layer annealed at 100 °C.

  7. Effect of annealing on pulse laser deposition grown copper oxide thin film

    Science.gov (United States)

    Mistry, Vaibhavi H.; Mistry, Bhaumik V.; Modi, B. P.; Joshi, U. S.

    2017-05-01

    Cuprous oxide (Cu2O) is a promising non-toxic and low cost semiconductor with potential applications in photovoltaic devices and sensor applications. Copper oxide thin films were prepared on glass substrate by pulse laser deposition. The effects of annealing on the structural, optical and electrical properties of copper oxide thin films were studied. The films were annealed in air for different temperature ranging from 200 to 450 °C. X-ray diffraction patterns reveals that the films as-deposited and annealed at 200 and 250 °C are of cuprite structure with composition Cu2O. Annealing at 300 °C and above converts these films to CuO phase. The atomic force microscopy results show that both the phase has nanocrystalline and particle size of the films is increasing with increase in annealing temperature. The conversion from Cu2O to CuO phase was confirmed by a shift in the optical band gap from 2.20 eV to 1.74 eV. The annealing conditions play a major role in the structural properties of copper oxide thin films.

  8. Effect of annealing on the compositional modulation of InAlAsSb

    Energy Technology Data Exchange (ETDEWEB)

    Baladés, N., E-mail: nuria.balades@uca.es [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); Sales, D.L.; Herrera, M.; Delgado, F.J. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); González, M. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Sotera Defense Solutions, 430 National Business Pkwy # 100, Annapolis Junction, MD 20701 (United States); Clark, K.; Pinsunkajana, P. [Intelligent Epitaxy Technology, Inc. Richardson, TX, 75801 (United States); Hoven, N.; Hubbard, S. [Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States); Tomasulo, S.; Walters, J.R. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Molina, S.I. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain)

    2017-02-15

    Highlights: • A post-growth annealing under As overpressure over 500 °C for several minutes induces a blue-shift in the InAlAsSb emission. • TEM analysis evidences that the small compositional fluctuations of the as-grown samples disappear after being annealed. • Annealing stimulates atomic diffusion of the quaternary, homogenizing their constituents and enhancing structural quality. - Abstract: The effect of a post-growth thermal treatment in two different heterostructures with InAlAsSb as the top layer grown by molecular beam epitaxy lattice-matched to InP, have been studied by diffraction contrast transmission electron microscopy (TEM). This novel top cell layer material with application in ultra-high efficiency solar cells were grown on (001) InP substrate with or without an InGaAs buffer layer. Initial photoluminescence (PL) measurements revealed deviations from their predicted bandgap, suggesting non-random atomic distribution of the quaternary layer. Then, a thermal annealing was performed at different temperatures and times. The effect on the structure of the InAlAsSb active layer caused by the new arrangement of layers and the post-growth annealing treatments has been reported. Our results show that the small compositional fluctuations of the as-grown heterostructures disappear after being annealed, and the bandgap energy correspondingly increases towards the predicted value.

  9. Degradation of high-Tc superconductors by annealing in dry and moist atmospheres

    International Nuclear Information System (INIS)

    Lee, W.; Nowick, A.S.

    1990-01-01

    A study is made of the effects of annealing both La 2-x Sr x CuO 4 (for x=0, 0.1, and 0.15) and YBa 2 Cu 3 O 7 in wet and dry O 2 atmospheres at various temperatures between 200 and 930 degree C. In the case of La 2-x Sr x CuO 4 , substantial degradation of resistive properties occurs during annealing in moist O 2 , the degradation being highest at 200 degree C as decreasing as the treatment temperature increases. Since the Meissner effect remains unaffected, it is concluded that degradation is due to the formation of a hydroxide species at grain boundaries, which decomposes as the anneal temperature is increased to 930 degree C. In the case of YBa 2 Cu 3 O 7 , on the other hand, moisture does not produce degradation for anneals at 200 degree C and above, but severe degradation of resistive behavior does occur for dry O 2 anneals, with a maximum effect at 500 degree C. It is found that this effect results from a contaminant gas absorbed by the furnace when it is open to air, possibly CO 2 . Again the degradation is due to formation of a grain-boundary phase which decomposes by annealing at 930 degree C

  10. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    International Nuclear Information System (INIS)

    Rhee, Joo Yull

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder → order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by presumption that the recrystallization would be realized in such a way that the average atomic spacing would be reduced

  11. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Science.gov (United States)

    Kusworo, T. D.; Aryanti, N.; Firdaus, M. M. H.; Sukmawati, H.

    2015-12-01

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  12. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Aryanti, N., E-mail: nita.aryanti@gmail.com; Firdaus, M. M. H.; Sukmawati, H. [Chemical Engineering, Faculty of Engineering, Diponegoro University Prof. Soedarto Street, Tembalang, Semarang, 50239, Phone/Fax : (024)7460058 (Indonesia)

    2015-12-29

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  13. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2008-05-31

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T {<=} 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process.

  14. Sensitivity study on hydraulic well testing inversion using simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Shinsuke; Najita, J.; Karasaki, Kenzi

    1997-11-01

    For environmental remediation, management of nuclear waste disposal, or geothermal reservoir engineering, it is very important to evaluate the permeabilities, spacing, and sizes of the subsurface fractures which control ground water flow. Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes an aperture of cluster of fracture elements, which are chosen randomly from a list of discrete apertures, to improve the match to observed pressure transients. The size of the clusters is held constant throughout the iterations. Sensitivity studies using simple fracture models with eight wells show that, in general, it is necessary to conduct interference tests using at least three different wells as pumping well in order to reconstruct the fracture network with a transmissivity contrast of one order of magnitude, particularly when the cluster size is not known a priori. Because hydraulic inversion is inherently non-unique, it is important to utilize additional information. The authors investigated the relationship between the scale of heterogeneity and the optimum cluster size (and its shape) to enhance the reliability and convergence of the inversion. It appears that the cluster size corresponding to about 20--40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and the practical range of spatial correlation is evaluated to be about 5--10 m from the optimal cluster size in the inversion.

  15. The Effects of Annealing Parameters on the Crystallization and Morphology of Cu(In,GaSe2 Absorber Layers Prepared by Annealing Stacked Metallic Precursors

    Directory of Open Access Journals (Sweden)

    Chia-Ho Huang

    2014-01-01

    Full Text Available CIGS films are prepared by single-stage annealing of the solid Se-coated In/Cu-Ga bilayer precursor. The annealing processes were performed using various Ar pressures, heating rates, and soaking times. A higher Ar pressure is needed to fabricate highly crystalline CIGS films, as no extra Se-vapor source is supplied. As the heating rate increases, the surface morphologies of the CIGS films become looser and some cracks are observed. However, the influence of soaking time is insignificant and the selenization process only requires a short time when the precursors are selenized at a higher temperature with a lower heating rate and a higher Ar pressure. In this study, a dense chalcopyrite CIGS film with a thickness of about 1.5-1.6 μm, with large grains (~1.2 μm and no cracking or peeling is obtained after selenizing at a temperature of 550°C, an Ar pressure of 300 Torr, a heating rate of 60°C/min, and a soaking time of 20 min. By adequate design of the stacked precursor and controlling the annealing parameters, single-stage annealing of the solid Se-coated In/Cu-Ga bilayer precursor is simplified for the fabrication of a fully crystallized chalcopyrite CIGS absorber layers with good crystallization and large grains.

  16. Hard magnetic properties of rapidly annealed NdFeB thin films on Nb and V buffer layers

    International Nuclear Information System (INIS)

    Jiang, H.; Evans, J.; O'Shea, M.J.; Du Jianhua

    2001-01-01

    NdFeB thin films of the form A (20 nm)/NdFeB(d nm)/A(20 nm), where d ranges from 54 to 540 nm and the buffer layer A is Nb or V were prepared on a Si(1 0 0) substrate by magnetron sputtering. The hard Nd 2 Fe 14 B phase is formed by a 30 s rapid anneal or a 20 min anneal. Average crystallite size ranged from 20 to 35 nm with the rapidly annealed samples having the smaller crystallite size. These samples also exhibited a larger coercivity and energy product than those treated by a 20 min vacuum anneal. A maximum coercivity of 26.3 kOe at room temperature was obtained for a Nb/NdFeB (180 nm)/Nb film after a rapid anneal at 725 deg. C. Initial magnetization curves indicate magnetization rotation rather than nucleation of reverse domains is important in the magnetization process. A Brown's equation analysis of the coercivity as a function of temperature allowed us to compare the rapidly annealed and 20 min annealed samples. This analysis suggests that rapid annealing gives higher quality crystalline grains than the 20 min annealed sample leading to the observed large coercivity in the rapidly annealed samples

  17. Comparative Study of Furnace and Flash Lamp Annealed Silicon Thin Films Grown by Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Maheshwar Shrestha

    2018-03-01

    Full Text Available Low-temperature growth of microcrystalline silicon (mc-Si is attractive for many optoelectronic device applications. This paper reports a detailed comparison of optical properties, microstructure, and morphology of amorphous silicon (a-Si thin films crystallized by furnace annealing and flash lamp annealing (FLA at temperatures below the softening point of glass substrate. The initial a-Si films were grown by plasma enhanced chemical vapor deposition (PECVD. Reflectance measurement indicated characteristic peak in the UV region ~280 nm for the furnace annealed (>550 °C and flash lamp annealed films, which provided evidence of crystallization. The film surface roughness increased with increasing the annealing temperature as well as after the flash lamp annealing. X-ray diffraction (XRD measurement indicated that the as-deposited samples were purely amorphous and after furnace crystallization, the crystallites tended to align in one single direction (202 with uniform size that increased with the annealing temperature. On the other hand, the flash lamp crystalized films had randomly oriented crystallites with different sizes. Raman spectroscopy showed the crystalline volume fraction of 23.5%, 47.3%, and 61.3% for the samples annealed at 550 °C, 650 °C, and with flash lamp, respectively. The flash lamp annealed film was better crystallized with rougher surface compared to furnace annealed ones.

  18. Conventional and rapid thermal annealing of spray pyrolyzed copper indium gallium sulfide thin films

    International Nuclear Information System (INIS)

    Aydin, Erkan; Sankir, Mehmet; Sankir, Nurdan Demirci

    2014-01-01

    Highlights: • Spray pyrolysis of copper indium gallium sulfide (CuInGaS 2 ) thin films. • Environmentally friendly method to produce solar cell quality absorber layers. • Effects of post-annealing process on the film properties of CuInGaS 2 . • Pros-and-cons of conventional and rapid thermal annealing. • Enhanced electrical and optical properties via annealing. - Abstract: With this study for the first time effects of post annealing on morphological, structural, optical and electrical properties of spray pyrolyzed copper–indium–gallium–sulfide (CuInGaS 2 ) thin films have been investigated. Pros-and-cons of conventional (CA) and rapid thermal annealing (RTA) have been discussed to obtain the high quality thin film absorbers for solar cell applications. X-ray diffraction analysis revealed that all of the spray pyrolyzed CuInGaS 2 thin films have chalcopyrite structures with a highly (1 1 2) preferential orientation. Raman spectra also confirmed this structure. However, metal oxide secondary phases such as copper oxide and gallium oxide were detected when the temperature ramp rate was increased during RTA process. Energy dispersive X-ray measurements revealed that both copper and gallium diffused through the surface after annealing processes. Moreover, copper diffusion became pronounced especially at high annealing temperatures. Optical transmission measurements in the wavelength range between 600 and 1100 nm showed that band gap energy of CuInGaS 2 thin films was ranging between 1.36 and 1.51 eV depending on the annealing conditions. Very high mobility values have been observed for both processes. The maximum electrical mobility, 30.9 cm 2 /V s, was observed for the films annealed at 600 °C via CA. This is the highest reported value among the CuInGaS 2 thin film absorbers deposited by both solution and vacuum based techniques. As a result, post-annealing of spray pyrolyzed CuInGaS 2 thin films without usage of highly toxic gases, reported in this

  19. A Quantum Annealing Computer Team Addresses Climate Change Predictability

    Science.gov (United States)

    Halem, M. (Principal Investigator); LeMoigne, J.; Dorband, J.; Lomonaco, S.; Yesha, Ya.; Simpson, D.; Clune, T.; Pelissier, C.; Nearing, G.; Gentine, P.; hide

    2016-01-01

    The near confluence of the successful launch of the Orbiting Carbon Observatory2 on July 2, 2014 and the acceptance on August 20, 2015 by Google, NASA Ames Research Center and USRA of a 1152 qubit D-Wave 2X Quantum Annealing Computer (QAC), offered an exceptional opportunity to explore the potential of this technology to address the scientific prediction of global annual carbon uptake by land surface processes. At UMBC,we have collected and processed 20 months of global Level 2 light CO2 data as well as fluorescence data. In addition we have collected ARM data at 2sites in the US and Ameriflux data at more than 20 stations. J. Dorband has developed and implemented a multi-hidden layer Boltzmann Machine (BM) algorithm on the QAC. Employing the BM, we are calculating CO2 fluxes by training collocated OCO-2 level 2 CO2 data with ARM ground station tower data to infer to infer measured CO2 flux data. We generate CO2 fluxes with a regression analysis using these BM derived weights on the level 2 CO2 data for three Ameriflux sites distinct from the ARM stations. P. Gentine has negotiated for the access of K34 Ameriflux data in the Amazon and is applying a neural net to infer the CO2 fluxes. N. Talik validated the accuracy of the BM performance on the QAC against a restricted BM implementation on the IBM Softlayer Cloud with the Nvidia co-processors utilizing the same data sets. G. Nearing and K. Harrison have extended the GSFC LIS model with the NCAR Noah photosynthetic parameterization and have run a 10 year global prediction of the net ecosystem exchange. C. Pellisier is preparing a BM implementation of the Kalman filter data assimilation of CO2 fluxes. At UMBC, R. Prouty is conducting OSSE experiments with the LISNoah model on the IBM iDataPlex to simulate the impact of CO2 fluxes to improve the prediction of global annual carbon uptake. J. LeMoigne and D. Simpson have developed a neural net image registration system that will be used for MODIS ENVI and will be

  20. Evolution on the structural and optical properties of SiOx films annealed in nitrogen atmosphere

    International Nuclear Information System (INIS)

    Coyopol, A.; Díaz-Becerril, T.; García-Salgado, G.; Juárez-Santisteban, H.; López, R.; Rosendo-Andrés, E.

    2014-01-01

    In this paper, thermal annealing in nitrogen atmosphere at temperatures from 900 to 1100 °C was done on the SiO x films to follow the changes in their optical and structural properties. Micro-Raman measurements revealed the existence of a nanocrystalline phase and it become dominant as the annealing temperature increased from 900 to 1100 °C. The last might be an indicative of presence of silicon clusters with high crystallization grade embedded in the SiO x matrix. X-ray diffractograms from samples annealed at 1100 °C showed reflections at 2θ=28.4, 47.3, and 56.1° ascribed to (1 1 1), (2 2 0), and (3 1 1) planes of the silicon respectively. HRTEM measurements confirmed the existence of silicon nanocrystals (Si-ncs) in the SiO x films and both the average size and number of the Si-ncs were modified by the annealing process. Photoluminescence (PL) measurement displayed a broad emission from 400 to 1100 nm. This emission was related to the number of nanocrystals and to the creation of interface defects in SiO x films. -- Highlights: • Si-ncs are synthesized from interaction between a silicon solid-source and hydrogen atoms. • The size modulation of Si-ncs by effect of the annealing temperature is studied. • Silicon clusters consist of a crystalline core surrounded by an amorphous silicon shell. • The average size and number of the Si-ncs are modified by the annealing effect. • The increase in the number of Si-ncs with annealing process causes radiative centers

  1. Recrystallization-Induced Surface Cracks of Carbon Ions Irradiated 6H-SiC after Annealing.

    Science.gov (United States)

    Ye, Chao; Ran, Guang; Zhou, Wei; Shen, Qiang; Feng, Qijie; Lin, Jianxin

    2017-10-25

    Single crystal 6H-SiC wafers with 4° off-axis [0001] orientation were irradiated with carbon ions and then annealed at 900 °C for different time periods. The microstructure and surface morphology of these samples were investigated by grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Ion irradiation induced SiC amorphization, but the surface was smooth and did not have special structures. During the annealing process, the amorphous SiC was recrystallized to form columnar crystals that had a large amount of twin structures. The longer the annealing time was, the greater the amount of recrystallized SiC would be. The recrystallization volume fraction was accorded with the law of the Johnson-Mehl-Avrami equation. The surface morphology consisted of tiny pieces with an average width of approximately 30 nm in the annealed SiC. The volume shrinkage of irradiated SiC layer and the anisotropy of newly born crystals during annealing process produced internal stress and then induced not only a large number of dislocation walls in the non-irradiated layer but also the initiation and propagation of the cracks. The direction of dislocation walls was perpendicular to the growth direction of the columnar crystal. The longer the annealing time was, the larger the length and width of the formed crack would be. A quantitative model of the crack growth was provided to calculate the length and width of the cracks at a given annealing time.

  2. Recrystallization-Induced Surface Cracks of Carbon Ions Irradiated 6H-SiC after Annealing

    Directory of Open Access Journals (Sweden)

    Chao Ye

    2017-10-01

    Full Text Available Single crystal 6H-SiC wafers with 4° off-axis [0001] orientation were irradiated with carbon ions and then annealed at 900 °C for different time periods. The microstructure and surface morphology of these samples were investigated by grazing incidence X-ray diffraction (GIXRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Ion irradiation induced SiC amorphization, but the surface was smooth and did not have special structures. During the annealing process, the amorphous SiC was recrystallized to form columnar crystals that had a large amount of twin structures. The longer the annealing time was, the greater the amount of recrystallized SiC would be. The recrystallization volume fraction was accorded with the law of the Johnson–Mehl–Avrami equation. The surface morphology consisted of tiny pieces with an average width of approximately 30 nm in the annealed SiC. The volume shrinkage of irradiated SiC layer and the anisotropy of newly born crystals during annealing process produced internal stress and then induced not only a large number of dislocation walls in the non-irradiated layer but also the initiation and propagation of the cracks. The direction of dislocation walls was perpendicular to the growth direction of the columnar crystal. The longer the annealing time was, the larger the length and width of the formed crack would be. A quantitative model of the crack growth was provided to calculate the length and width of the cracks at a given annealing time.

  3. NEXAFS Study of the Annealing Effect on the Local Structure of FIB-CVD DLC

    International Nuclear Information System (INIS)

    Saikubo, Akihiko; Kato, Yuri; Igaki, Jun-ya; Kanda, Kazuhiro; Matsui, Shinji; Kometani, Reo

    2007-01-01

    Annealing effect on the local structure of diamond like carbon (DLC) formed by focused ion beam-chemical vapor deposition (FIB-CVD) was investigated by the measurement of near edge x-ray absorption fine structure (NEXAFS) and energy dispersive x-ray (EDX) spectra. Carbon K edge absorption NEXAFS spectrum of FIB-CVD DLC was measured in the energy range of 275-320 eV. In order to obtain the information on the location of the gallium in the depth direction, incidence angle dependence of NEXAFS spectrum was measured in the incident angle range from 0 deg. to 60 deg. . The peak intensity corresponding to the resonance transition of 1s→σ* originating from carbon-gallium increased from the FIB-CVD DLC annealed at 200 deg. C to the FIB-CVD DLC annealed at 400 deg. C and decreased from that at 400 deg. C to that at 600 deg. C. Especially, the intensity of this peak remarkably enhanced in the NEXAFS spectrum of the FIB-CVD DLC annealed at 400 deg. C at the incident angle of 60 deg. . On the contrary, the peak intensity corresponding to the resonance transition of 1s→π* originating from carbon double bonding of emission spectrum decreased from the FIB-CVD DLC annealed at 200 deg. C to that at 400 deg. C and increased from that at 400 deg. C to that at 600 deg. C. Gallium concentration in the FIB-CVD DLC decreased from ≅2.2% of the as-deposited FIB-CVD DLC to ≅1.5% of the FIB-CVD DLC annealed at 600 deg. C from the elementary analysis using EDX. Both experimental results indicated that gallium atom departed from FIB-CVD DLC by annealing at the temperature of 600 deg. C

  4. How to Control Component Ratio of Conducting Polymer Blend for Organic Photovoltaic Devices by Annealing

    Directory of Open Access Journals (Sweden)

    Bobins Augustine

    2015-01-01

    Full Text Available There are various conducting polymer blends which are used as hole transporting layers (HTL in organic photovoltaic devices (OPV. The electrical performance of these conducting polymer blends depends crucially on its surface compositions and morphology. In this paper, we studied poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate or PEDOT:PSS as an example of the HTL conducting polymer blends used in OPV. We have investigated the effect of annealing PEDOT:PSS in different atmospheres such as vacuum, N2, and air at different temperatures. It was found that the component ratio of the polymer blend is changing with annealing temperature and atmosphere. PSS/PEDOT ratio was found to have clear influence on the electrical performance of the material. In practice, we found that annealing can be used as a method to control component ratio of the HTL conducting polymer blend to achieve better electrical performance in OPV devices. The component ratio changes of the polymer with annealing were understood by X-ray photoelectron spectroscopy (XPS. Annealing in N2 atmosphere at 220°C for 1 hour gave best electrical performance for the polymer and the PSS/PEDOT ratio at that condition was close to 1.1, while the initial ratio was 2.5. Optimizing HTL layer by simple conductivity measurement does not guarantee best performance in OPV since surface property changes during annealing might affect the deposition of successive active layers on top and thus final device. Thus we have optimized annealing condition of the HTL layer according to the OPV performance itself.

  5. Numerical analysis on effect of annealing mc-Si ingot grown by DS process for PV application

    Science.gov (United States)

    Aravindan, G.; Srinivasan, M.; Aravinth, K.; Ramasamy, P.

    2017-10-01

    Silicon solar cells play a crucial role in Photo voltaic (PV) application. We have numerically investigated thermal stress and normal stress components (Sigma 11, Sigma 22, Sigma 33 and sigma 12) by using finite volume method. The maximum thermal stress has low value at the centre region for 900 K and 700 K annealing temperatures comparing all the cases. The maximum thermal stress at peripheral region is low for 700 K annealing compared to 900 K annealing. The annealing effect of mc-Si ingot normal stress components is discussed. At 700 K annealing temperature the normal stress in 11 and 33 direction has lower maximum and at the 900 K annealing temperature the normal stress in 22 and 12 direction has lower maximum.

  6. Effects of annealing on the structure and magnetic properties of Fe80B20 magnetostrictive fibers.

    Science.gov (United States)

    Zhu, Qianke; Zhang, Shuling; Geng, Guihong; Li, Qiushu; Zhang, Kewei; Zhang, Lin

    2016-07-04

    Fe80B20 amorphous alloys exhibit excellent soft magnetic properties, high abrasive resistance and outstanding corrosion resistance. In this work, Fe80B20 amorphous micro-fibers with HC of 3.33 Oe were firstly fabricated and the effects of annealing temperature on the structure and magnetic properties of the fibers were investigated. In this study, Fe80B20 amorphous fibers were prepared by the single roller melt-spinning method. The structures of as-spun and annealed fibers were investigated by X-ray diffractometer (XRD) (PANalytical X,Pert Power) using Cu Kα radiation. The morphology of the fibers was observed by scanning electron microscopy (SEM) (HITACHI-S4800). Differential scanning calorimetry (DSC) measurements of the fibers were performed on Mettler Toledo TGA/DSC1 device under N2 protection. Vibrating sample magnetometer (VSM, Versalab) was used to examine the magnetic properties of the fibers. The resonance behavior of the fibers was characterized by an impedance analyzer (Agilent 4294A) with a home-made copper coil. The X-ray diffusion (XRD) patterns show that the fibers remain amorphous structure until the annealing temperature reaches 500°C. The differential scanning calorimetry (DSC) results show that the crystallization temperature of the fibers is 449°C. The crystallization activation energy is calculated to be 221 kJ/mol using Kissinger formula. The scanning electron microscopy (SEM) images show that a few dendrites appear at the fiber surface after annealing. The result indicates that the coercivity HC (//) and HC (⊥) slightly increases with increasing annealing temperature until 400°C, and then dramatically increases with further increasing annealing temperature which is due to significant increase in magneto-crystalline anisotropy and magneto-elastic anisotropy. The Q value firstly increases slightly when the annealing temperature rises from room temperature (RT) to 300°C, then decreases until 400°C. Eventually, the value of Q increases to

  7. Influence of annealing temperature on the Dy diffusion process in NdFeB magnets

    Science.gov (United States)

    Hu, Sheng-qing; Peng, Kun; Chen, Hong

    2017-03-01

    Sintered NdFeB magnets were coated with a layer of Dy metal using electron beam evaporation method and then annealed at various temperatures to investigate the temperature dependence of Dy diffusion process in NdFeB magnets. A Dy-rich phase was observed along the grain boundaries after the grain boundary diffusion process, the diffusion coefficients of various temperatures were obtained, the diffusion coefficients of Dy along the grain boundaries at 800 °C and 900 °C were determined to be 9.8×10-8 cm2 s-1 and 2.4×10-7 cm2 s-1, respectively. The diffusion length depended on the annealing temperature and the maximum diffusion length of approximately 1.8 mm and 3.0 mm can be obtained after annealing at 800 °C and 900 °C for 8 h. Higher diffusion temperature results in the diffusion not only along the grain boundaries but also into grains and then decrease in magnetic properties. The optimum annealing conditions can be determined as 900 °C for 8 h. The coercivity was improved from 1040 kA/m to 1450 kA/m and its magnetization has no significant reduction after the grain boundary diffusion process at the optimum annealing conditions.

  8. Effect of annealing process on TiN/TiC bilayers grown by pulsed arc discharge

    International Nuclear Information System (INIS)

    Ramos-Rivera, L.; Escobar, D.; Benavides-Palacios, V.; Arango, P.J.; Restrepo-Parra, E.

    2012-01-01

    In this work, a study of annealing process effect on TiN/TiC bilayer is presented. The annealing temperature was varied between room temperature and 500 °C. Materials were produced by the plasma-assisted pulsed vacuum arc discharge technique. In order to grow the films, a target of Ti with 99.9999% purity and stainless-steel 304 substrate were used. For the production of TiN layer, the reaction chamber was filled up with nitrogen gas until reaching 25 Pa and the discharge was performed at 310 V. The TiC layer was grown in a methane atmosphere at 30 Pa and 270 V. X-ray diffraction and X photoelectron spectroscopy were employed for studying the structure and chemical composition evolution during the annealing process. At 400 °C, TiO 2 phase begun to appear and it was well observed at 500 °C. Crystallite size and microstrain was obtained as a function of the annealing temperature. XPS technique was employed for analyzing the bilayers before and after the annealing process. Narrow spectra of Ti2p, N1s and O1s were obtained, presenting TiO phases.

  9. Open-System Quantum Annealing in Mean-Field Models with Exponential Degeneracy*

    Directory of Open Access Journals (Sweden)

    Kostyantyn Kechedzhi

    2016-05-01

    Full Text Available Real-life quantum computers are inevitably affected by intrinsic noise resulting in dissipative nonunitary dynamics realized by these devices. We consider an open-system quantum annealing algorithm optimized for such a realistic analog quantum device which takes advantage of noise-induced thermalization and relies on incoherent quantum tunneling at finite temperature. We theoretically analyze the performance of this algorithm considering a p-spin model that allows for a mean-field quasiclassical solution and, at the same time, demonstrates the first-order phase transition and exponential degeneracy of states, typical characteristics of spin glasses. We demonstrate that finite-temperature effects introduced by the noise are particularly important for the dynamics in the presence of the exponential degeneracy of metastable states. We determine the optimal regime of the open-system quantum annealing algorithm for this model and find that it can outperform simulated annealing in a range of parameters. Large-scale multiqubit quantum tunneling is instrumental for the quantum speedup in this model, which is possible because of the unusual nonmonotonous temperature dependence of the quantum-tunneling action in this model, where the most efficient transition rate corresponds to zero temperature. This model calculation is the first analytically tractable example where open-system quantum annealing algorithm outperforms simulated annealing, which can, in principle, be realized using an analog quantum computer.

  10. Sequential multiple-step europium ion implantation and annealing of GaN

    KAUST Repository

    Miranda, S. M C

    2014-01-20

    Sequential multiple Eu ion implantations at low fluence (1×1013 cm-2 at 300 keV) and subsequent rapid thermal annealing (RTA) steps (30 s at 1000 °C or 1100 °C) were performed on high quality nominally undoped GaN films grown by metal organic chemical vapour deposition (MOCVD) and medium quality GaN:Mg grown by hydride vapour phase epitaxy (HVPE). Compared to samples implanted in a single step, multiple implantation/annealing shows only marginal structural improvement for the MOCVD samples, but a significant improvement of crystal quality and optical activation of Eu was achieved in the HVPE films. This improvement is attributed to the lower crystalline quality of the starting material, which probably enhances the diffusion of defects and acts to facilitate the annealing of implantation damage and the effective incorporation of the Eu ions in the crystal structure. Optical activation of Eu3+ ions in the HVPE samples was further improved by high temperature and high pressure annealing (HTHP) up to 1400 °C. After HTHP annealing the main room temperature cathodo- and photoluminescence line in Mg-doped samples lies at ∼ 619 nm, characteristic of a known Mg-related Eu3+ centre, while after RTA treatment the dominant line lies at ∼ 622 nm, typical for undoped GaN:Eu. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The role of proximity caps during the annealing of UV-ozone oxidized GaAs

    Science.gov (United States)

    Ghosh, S. C.; Biesinger, M. C.; LaPierre, R. R.; Kruse, P.

    2007-06-01

    This study provides a deeper insight into the chemistry and physics of the common engineering practice of using a proximity cap, while annealing compound semiconductors such as GaAs. We have studied the cases of a GaAs proximity cap, a Si proximity cap, and no proximity cap. Using x-ray photoelectron spectroscopy, it has been found that annealing increases the gallium to arsenic ratio in the oxide layer in all cases. During the annealing of UV-ozone oxidized GaAs, it has been observed that GaAs proximity caps also serve as a sacrificial layer to accelerate the desorption of oxide species. In all cases surface deterioration due to pit formation has been observed, and the depth of pits is found to depend on the effective role played by the capping material. Energy dispersive x-ray analysis provides additional evidence that pits mainly consist of elemental As and gallium oxide, with most of the elemental As situated at the pit-substrate interface. Deposition of a thin layer of gold and subsequent annealing to 500°C for 300s under different capping conditions shows the use of a proximate cap to be practically insignificant in annealing Au deposited films.

  12. INFLUENCE OF ANNEALING ON HARDNESS OF Cr-Mn-Ni CAST IRONS

    Directory of Open Access Journals (Sweden)

    V. V. Netrebko

    2015-01-01

    Full Text Available The necessary level of material’s hardness is determined by the exploitation conditions and presence of technological operations during manufacturing of articles. Mechanical edge cutting machining of wear resistant materials is impeded because of their high hardness. It is recommended to apply annealing in order to decrease hardness and improve machinability. The purpose of the work consisted in obtaining of regression dependences of cast iron’s macrohardness on its chemical content after annealing at 730 °С. With the use of mathematical experimental design the regression dependences of cast iron’s macrohardness and structural components’ microhardness on С, Cr, Mn, Ni content have been established. The minimal hardness of 27,6 HRC after annealing at 730 °С is obtained in the cast iron containing: 3,9% С; 11,4% Cr; 0,6% Mn; 0,2% Ni. The maximal hardness of 70,4 HRC is obtained when the content is as follows: 1,1% С; 25,6% Cr; 5,4% Mn; 3,0% Ni. Annealing at 730 °С decreases the cast irons’ hardness containing the minimal amount of Cr, Mn and Ni. Annealing at 730 °С is recommended for cast irons alloyed by Mn and Ni for increasing of hardness.

  13. AFM, XRD and HRTEM Studies of Annealed FePd Thin Films

    International Nuclear Information System (INIS)

    Perzanowski, M.; Zabila, Y.; Polit, A.; Krupinski, M.; Dobrowolska, A.; Marszalek, M.; Morgiel, J.

    2010-01-01

    Ferromagnetic FePd L1 0 ordered alloys are highly expected as forthcoming high-density recording materials, because they reveal a large perpendicular magnetocrystalline anisotropy. The value of the magnetic anisotropy of FePd alloy strongly depends on the alloy composition, degree of alloy order as well as on the crystallographic grain orientation. In particular, to obtain the perpendicular anisotropy, it is necessary to get the films with (001) texture. One of the successful methods, which allows one to obtain highly ordered alloy, is a subsequent deposition of Fe and Pd layers, followed by an annealing at high temperature. This paper presents the study of the FePd thin alloy film structure changing in the result of high temperature annealing. During the annealing in high vacuum, the measurements of electrical resistance were performed, indicating the regions of different structure evolution. Changes in the crystal structure and surface morphology induced by thermal treatment were investigated by X-ray diffraction, atomic force microscopy, as well as high resolution transmission electron microscopy and then compared with electrical resistivity measurement. The slow thermal annealing of the deposited layers leads to the formation of L1 0 ordered FePd alloy with preferred (111) grain orientation. After the annealing at the highest used temperature, the dewetting process was observed, resulting in a creation of well oriented, regular nanoparticles. (author)

  14. Effects of annealing temperature in a metal alloy nano-dot memory

    International Nuclear Information System (INIS)

    Lee, Jung Min; Lee, Gae Hun; Song, Yun Heub; Bea, Ji Cheol; Tanaka, Tetsu

    2011-01-01

    The annealing temperature dependence of the capacitance-voltage (C-V) characteristic has been studied in a metal-oxide semiconductor structure containing FePt nano-dots. Several in-situ annealing temperatures from 400 to ∼700 .deg. C in a high vacuum ambience (under 1 x 10 -5 Pa) were evaluated in view of the cell's characteristics and its reliability. Here, we demonstrate that the annealing temperature is significant for memory performance in an alloy metal nano-dot structure. A higher in-situ temperature provides better retention and a more reliable memory window. In the sample with an in-situ annealing condition of 700 .deg. C for 30 min, a memory window of 9.2 V at the initial stage was obtained, and a memory window of 6.2 V after 10 years was estimated, which is reliable for a non-volatile memory. From these results, the annealing condition for an alloy metal nano-dot memory is one of the critical parameters for the memory characteristics, and should be optimized for better memory performance.

  15. Effect of High-Temperature Annealing on Ion-Implanted Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Hyunpil Boo

    2012-01-01

    Full Text Available P-type and n-type wafers were implanted with phosphorus and boron, respectively, for emitter formation and were annealed subsequently at 950∼1050∘C for 30∼90 min for activation. Boron emitters were activated at 1000∘C or higher, while phosphorus emitters were activated at 950∘C. QSSPC measurements show that the implied Voc of boron emitters increases about 15 mV and the J01 decreases by deep junction annealing even after the activation due to the reduced recombination in the emitter. However, for phosphorus emitters the implied Voc decreases from 622 mV to 560 mV and the J01 increases with deep junction annealing. This is due to the abrupt decrease in the bulk lifetime of the p-type wafer itself from 178 μs to 14 μs. PC1D simulation based on these results shows that, for p-type implanted solar cells, increasing the annealing temperature and time abruptly decreases the efficiency (Δηabs=−1.3%, while, for n-type implanted solar cells, deep junction annealing increases the efficiency and Voc, especially (Δηabs=+0.4% for backside emitter solar cells.

  16. Characteristics of layered tin disulfide deposited by atomic layer deposition with H2S annealing

    Directory of Open Access Journals (Sweden)

    Seungjin Lee

    2017-04-01

    Full Text Available Tin disulfide (SnS2 has attracted much attention as a two-dimensional (2D material. A high-quality, low-temperature process for producing 2D materials is required for future electronic devices. Here, we investigate tin disulfide (SnS2 layers deposited via atomic layer deposition (ALD using tetrakis(dimethylaminotin (TDMASn as a Sn precursor and H2S gas as a sulfur source at low temperature (150° C. The crystallinity of SnS2 was improved by H2S gas annealing. We carried out H2S gas annealing at various conditions (250° C, 300° C, 350° C, and using a three-step method. Angle-resolved X-ray photoelectron spectroscopy (ARXPS results revealed the valence state corresponding to Sn4+ and S2- in the SnS2 annealed with H2S gas. The SnS2 annealed with H2S gas had a hexagonal structure, as measured via X-ray diffraction (XRD and the clearly out-of-plane (A1g mode in Raman spectroscopy. The crystallinity of SnS2 was improved after H2S annealing and was confirmed using the XRD full-width at half-maximum (FWHM. In addition, high-resolution transmission electron microscopy (HR-TEM images indicated a clear layered structure.

  17. Thermal annealing recovery of fracture toughness in HT9 steel after irradiation to high doses

    Science.gov (United States)

    Byun, Thak Sang; Baek, Jong-Hyuk; Anderoglu, Osman; Maloy, Stuart A.; Toloczko, Mychailo B.

    2014-06-01

    The HT9 ferritic/martensitic steel with a nominal chemistry of Fe(bal.)12%Cr1%MoVW has been used as a primary core material for fast fission reactors such as FFTF because of its high resistance to radiation-induced swelling and embrittlement. Both static and dynamic fracture test results have shown that the HT9 steel can become brittle when it is exposed to high dose irradiation at a relatively low temperature (steel after irradiation up to 3148 dpa at 378504 °C. A specimen reuse technique has been established and applied to this study: the fracture specimens were tested Charpy specimens or broken halves of Charpy bars (13 × 3 × 4 mm). The post-anneal fracture test results indicated that much of the radiation-induced damage can be recovered by a simple thermal annealing schedule: the fracture toughness was incompletely recovered by 550 °C annealing, while nearly complete or complete recovery occurred after 650 °C annealing. This indicates that thermal annealing is a feasible damage mitigation technique for the reactor components made of HT9 steel. The partial recovery is probably due to the non-removable microstructural damages such as void or gas bubble formation, elemental segregation and precipitation.

  18. Ideal versus real: simulated annealing of experimentally derived and geometric platinum nanoparticles

    Science.gov (United States)

    Ellaby, Tom; Aarons, Jolyon; Varambhia, Aakash; Jones, Lewys; Nellist, Peter; Ozkaya, Dogan; Sarwar, Misbah; Thompsett, David; Skylaris, Chris-Kriton

    2018-04-01

    Platinum nanoparticles find significant use as catalysts in industrial applications such as fuel cells. Research into their design has focussed heavily on nanoparticle size and shape as they greatly influence activity. Using high throughput, high precision electron microscopy, the structures of commercially available Pt catalysts have been determined, and we have used classical and quantum atomistic simulations to examine and compare them with geometric cuboctahedral and truncated octahedral structures. A simulated annealing procedure was used both to explore the potential energy surface at different temperatures, and also to assess the effect on catalytic activity that annealing would have on nanoparticles with different geometries and sizes. The differences in response to annealing between the real and geometric nanoparticles are discussed in terms of thermal stability, coordination number and the proportion of optimal binding sites on the surface of the nanoparticles. We find that annealing both experimental and geometric nanoparticles results in structures that appear similar in shape and predicted activity, using oxygen adsorption as a measure. Annealing is predicted to increase the catalytic activity in all cases except the truncated octahedra, where it has the opposite effect. As our simulations have been performed with a classical force field, we also assess its suitability to describe the potential energy of such nanoparticles by comparing with large scale density functional theory calculations.

  19. Enabling Inkjet Printed Graphene for Ion Selective Electrodes with Postprint Thermal Annealing.

    Science.gov (United States)

    He, Qing; Das, Suprem R; Garland, Nathaniel T; Jing, Dapeng; Hondred, John A; Cargill, Allison A; Ding, Shaowei; Karunakaran, Chandran; Claussen, Jonathan C

    2017-04-12

    Inkjet printed graphene (IPG) has recently shown tremendous promise in reducing the cost and complexity of graphene circuit fabrication. Herein we demonstrate, for the first time, the fabrication of an ion selective electrode (ISE) with IPG. A thermal annealing process in a nitrogen ambient environment converts the IPG into a highly conductive electrode (sheet resistance changes from 52.8 ± 7.4 MΩ/□ for unannealed graphene to 172.7 ± 33.3 Ω/□ for graphene annealed at 950 °C). Raman spectroscopy and field emission scanning electron microscopy (FESEM) analysis reveals that the printed graphene flakes begin to smooth at an annealing temperature of 500 °C and then become more porous and more electrically conductive when annealed at temperatures of 650 °C and above. The resultant thermally annealed, IPG electrodes are converted into potassium ISEs via functionalization with a poly(vinyl chloride) (PVC) membrane and valinomycin ionophore. The developed potassium ISE displays a wide linear sensing range (0.01-100 mM), a low detection limit (7 μM), minimal drift (8.6 × 10 -6 V/s), and a negligible interference during electrochemical potassium sensing against the backdrop of interfering ions [i.e., sodium (Na), magnesium (Mg), and calcium (Ca)] and artificial eccrine perspiration. Thus, the IPG ISE shows potential for potassium detection in a wide variety of human fluids including plasma, serum, and sweat.

  20. Effects of recrystallization annealing on mechanical properties of cold-rolled PdNi5 wires

    Directory of Open Access Journals (Sweden)

    Aleksandra Ivanović

    2016-03-01

    Full Text Available The aim of this investigation was to determine the influence of the recrystallization temperature and recrystallization time on the microstructure and mechanical properties of the PdNi5 alloy subjected to cold deformation in the process of rolling at a constant deformation degree. The samples of PdNi5 alloy were recrystallization annealed within the temperature range of 200-1000ºC and annealing time range of 20-45 min after cold rolling with deformation degree of 97%. The tensile test was carried out using universal material testing machine. The hardness was also measured on the combined device for measuring Vickers and Brinell hardness. Metallographic observations were performed on an optical microscope. The analysis of the results of investigations regarding the microstructural changes and corresponding mechanical properties of cold-rolled PdNi5 strips shows that annealing temperature of 500ºC was sufficient to activate the energy for various recrystallization processes causing a change in the mechanical properties of cold-rolled PdNi5 strips. The annealing time, at constant annealing temperature, almost did not affect a recrystallization temperature and the mechanical properties of the cold-rolled PdNi5 strips.

  1. Atomic scale imaging of structural changes in solid electrolyte lanthanum lithium niobate upon annealing

    International Nuclear Information System (INIS)

    Hu, Xiaobing; Fisher, Craig A.J.; Kobayashi, Shunsuke; Ikuhara, Yumi H.; Fujiwara, Yasuyuki; Hoshikawa, Keigo; Moriwake, Hiroki; Kohama, Keiichi; Iba, Hideki; Ikuhara, Yuichi

    2017-01-01

    La (1-x)/3 Li x NbO 3 (LLNbO) is a promising electrolyte material for solid-state lithium-ion batteries because it is stable in contact with Li metal and contains a high concentration of intrinsic Li-ion vacancies. One strategy for improving its ionic conductivity and making it more competitive with other solid-state Li-ion electrolytes is to disorder the Li-ion vacancies by appropriate post-synthesis heat treatment, e.g., annealing. In this study, we examine the effects of annealing on single crystals of LLNbO with Li contents x = 0.07 and 0.13 based on simultaneous atomic resolution high angle annular dark field and annular bright field imaging methods using state-of-the-art aberration corrected scanning transmission electron microscopes. It is found that La modulation within A1 layers of the cation-deficient layered perovskite structure becomes more diffuse after annealing. In addition, some La atoms move to A-site positions and O4 window positions in the nominally vacant A2 layer, while O atom columns in this layer become rumpled in the [001] p direction, indicating that the NbO 6 octahedra are more heavily distorted after annealing. The observed crystal structure differences between as-prepared and annealed single crystals explain the drop in Li-ion conductivities of LLNbO single crystals after heat treatment.

  2. Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

    Directory of Open Access Journals (Sweden)

    Chuan Lung Chuang

    2015-01-01

    Full Text Available Indium tin oxide (ITO thin films were grown on glass substrates by direct current (DC reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were -1.6E+20 cm−3, 2.7E+01 cm2/Vs, 1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.

  3. Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells

    Science.gov (United States)

    Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

    1990-01-01

    The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

  4. SAGRAD: A Program for Neural Network Training with Simulated Annealing and the Conjugate Gradient Method.

    Science.gov (United States)

    Bernal, Javier; Torres-Jimenez, Jose

    2015-01-01

    SAGRAD (Simulated Annealing GRADient), a Fortran 77 program for computing neural networks for classification using batch learning, is discussed. Neural network training in SAGRAD is based on a combination of simulated annealing and Møller's scaled conjugate gradient algorithm, the latter a variation of the traditional conjugate gradient method, better suited for the nonquadratic nature of neural networks. Different aspects of the implementation of the training process in SAGRAD are discussed, such as the efficient computation of gradients and multiplication of vectors by Hessian matrices that are required by Møller's algorithm; the (re)initialization of weights with simulated annealing required to (re)start Møller's algorithm the first time and each time thereafter that it shows insufficient progress in reaching a possibly local minimum; and the use of simulated annealing when Møller's algorithm, after possibly making considerable progress, becomes stuck at a local minimum or flat area of weight space. Outlines of the scaled conjugate gradient algorithm, the simulated annealing procedure and the training process used in SAGRAD are presented together with results from running SAGRAD on two examples of training data.

  5. Annealing effects on electrical conductivity and thermoelectric power of sintered PbTe

    International Nuclear Information System (INIS)

    Rosenzweig, J.; Zhang, J.; Birkholz, U.

    1984-01-01

    The electrical conductivity and the thermoelectric power of p-type and n-type sintered polycrystalline PbTe samples are measured in the temperature range 130 K < T < 850 K in order to investigate aging phenomena caused by annealing. The annealing procedure chosen is similar to the operation conditions of thermoelectric generators with a maximum temperature of 850 K. The conductivity of p-type sodium-doped PbTe decreases significantly at temperatures below 400 K after several annealing cycles of 60 h. The thermoelectric power and the Hall coefficient, however, show no corresponding increase. The decrease of conductivity in this case can be explained by a barrier model the equivalent circuit of wich includes three temperature dependent resistors. The parameters of this model are determined by fitting the calculated conductivity to experimental data. Bromine-doped n-type PbTe shows only a slight decrease of conductivity after annealing. In the case of p-type silver-doped PbTe-SnTe-MnTe, the same annealing procedure has almost no effect on the electrical properties. (author)

  6. Multiphase Simulated Annealing Based on Boltzmann and Bose-Einstein Distribution Applied to Protein Folding Problem.

    Science.gov (United States)

    Frausto-Solis, Juan; Liñán-García, Ernesto; Sánchez-Hernández, Juan Paulo; González-Barbosa, J Javier; González-Flores, Carlos; Castilla-Valdez, Guadalupe

    2016-01-01

    A new hybrid Multiphase Simulated Annealing Algorithm using Boltzmann and Bose-Einstein distributions (MPSABBE) is proposed. MPSABBE was designed for solving the Protein Folding Problem (PFP) instances. This new approach has four phases: (i) Multiquenching Phase (MQP), (ii) Boltzmann Annealing Phase (BAP), (iii) Bose-Einstein Annealing Phase (BEAP), and (iv) Dynamical Equilibrium Phase (DEP). BAP and BEAP are simulated annealing searching procedures based on Boltzmann and Bose-Einstein distributions, respectively. DEP is also a simulated annealing search procedure, which is applied at the final temperature of the fourth phase, which can be seen as a second Bose-Einstein phase. MQP is a search process that ranges from extremely high to high temperatures, applying a very fast cooling process, and is not very restrictive to accept new solutions. However, BAP and BEAP range from high to low and from low to very low temperatures, respectively. They are more restrictive for accepting new solutions. DEP uses a particular heuristic to detect the stochastic equilibrium by applying a least squares method during its execution. MPSABBE parameters are tuned with an analytical method, which considers the maximal and minimal deterioration of problem instances. MPSABBE was tested with several instances of PFP, showing that the use of both distributions is better than using only the Boltzmann distribution on the classical SA.

  7. Effect of annealing process on TiN/TiC bilayers grown by pulsed arc discharge

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Rivera, L., E-mail: lramosr@unal.edu.co [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Aeropuerto Campus La Nubia (Colombia); Escobar, D.; Benavides-Palacios, V.; Arango, P.J.; Restrepo-Parra, E. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Aeropuerto Campus La Nubia (Colombia)

    2012-08-15

    In this work, a study of annealing process effect on TiN/TiC bilayer is presented. The annealing temperature was varied between room temperature and 500 Degree-Sign C. Materials were produced by the plasma-assisted pulsed vacuum arc discharge technique. In order to grow the films, a target of Ti with 99.9999% purity and stainless-steel 304 substrate were used. For the production of TiN layer, the reaction chamber was filled up with nitrogen gas until reaching 25 Pa and the discharge was performed at 310 V. The TiC layer was grown in a methane atmosphere at 30 Pa and 270 V. X-ray diffraction and X photoelectron spectroscopy were employed for studying the structure and chemical composition evolution during the annealing process. At 400 Degree-Sign C, TiO{sub 2} phase begun to appear and it was well observed at 500 Degree-Sign C. Crystallite size and microstrain was obtained as a function of the annealing temperature. XPS technique was employed for analyzing the bilayers before and after the annealing process. Narrow spectra of Ti2p, N1s and O1s were obtained, presenting TiO phases.

  8. Sequential multiple-step europium ion implantation and annealing of GaN

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, S.M.C. [Instituto Superior Tecnico, Campus Tecnologico e Nuclear, Estrada Nacional 10, 2695-066 Bobadela LRS (Portugal); Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001 Leuven (Belgium); Edwards, P.R.; O' Donnell, K.P. [SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom); Bockowski, M. [Institute of High Pressure Physics, Polish Academy of Sciences, 01-142 Warsaw (Poland); Alves, E.; Lorenz, K. [Instituto Superior Tecnico, Campus Tecnologico e Nuclear, Estrada Nacional 10, 2695-066 Bobadela LRS (Portugal); Roqan, I.S. [King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal 23955-6900 (Saudi Arabia); Vantomme, A. [Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001 Leuven (Belgium)

    2014-02-15

    Sequential multiple Eu ion implantations at low fluence (1 x 10{sup 13} cm{sup -2} at 300 keV) and subsequent rapid thermal annealing (RTA) steps (30 s at 1000 C or 1100 C) were performed on high quality nominally undoped GaN films grown by metal organic chemical vapour deposition (MOCVD) and medium quality GaN:Mg grown by hydride vapour phase epitaxy (HVPE). Compared to samples implanted in a single step, multiple implantation/annealing shows only marginal structural improvement for the MOCVD samples, but a significant improvement of crystal quality and optical activation of Eu was achieved in the HVPE films. This improvement is attributed to the lower crystalline quality of the starting material, which probably enhances the diffusion of defects and acts to facilitate the annealing of implantation damage and the effective incorporation of the Eu ions in the crystal structure. Optical activation of Eu{sup 3+} ions in the HVPE samples was further improved by high temperature and high pressure annealing (HTHP) up to 1400 C. After HTHP annealing the main room temperature cathodo- and photoluminescence line in Mg-doped samples lies at ∝ 619 nm, characteristic of a known Mg-related Eu{sup 3+} centre, while after RTA treatment the dominant line lies at ∝ 622 nm, typical for undoped GaN:Eu. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Optimization of Cold Rolling and Subsequent Annealing Treatment on Mechanical Properties of TWIP Steel

    Science.gov (United States)

    Zamani, D.; Golshan, A.; Dini, G.; Ismarrubie, Z. N.; Azmah Hanim, M. A.; Sajuri, Z.

    2017-08-01

    This research work studied the effect of cold rolling reduction and subsequent annealing temperature on the microstructural evolution and the mechanical properties of Fe-32Mn-4Si-2Al twinning-induced plasticity steel plates. For this, uniaxial tensile tests were carried out for three cold rolling reductions (50, 65 and 80%) and subsequent annealing treatment at 550-750 °C for 1.8 ks. The results were discussed in terms of the yield strength, ultimate tensile strength and total elongation and its dependence on the introduced microstructure. Regression analysis was used to develop the mathematical models of the mechanical properties. Moreover, analysis of variance was employed to verify the precision of the mathematical models. Finally, desirability function was used as an effective optimization approach for multi-objective optimization of the cold rolling reduction and annealing temperature. It is considerable that there is no research attempting to find optimum mechanical properties of the steels using this approach. The results indicated that applying large cold rolling reduction (upper than 75%) and subsequent annealing treatment in the recovery region and also the application of large cold rolling reduction and the subsequent annealing treatment in the lower limit of partial recrystallization region were effective methods to obtain an excellent combination of mechanical properties.

  10. Characterization for Ceramic-coated magnets using E-beam and thermal annealing methods

    International Nuclear Information System (INIS)

    Kim, Hyug Jong; Kim, Hee Gyu; Kang, In Gu; Kim, Min Wan; Yang, Ki Ho; Lee, Byung Cheol; Choi, Byung Ho

    2009-01-01

    Hard magnet was usually used by coating SiO 2 ceramic thick films followed by the thermal annealing process. In this work, the alternative annealing process for NdFeB magnets using e-beam sources(1∼2 MeV, 50∼400 kGy) was investigated. NdFeB magnets was coated with ceramic thick films using the spray method. The optimal annealing parameter for e-beam source reveals to be 1 MeV and 300 kGy. The sample prepared at 1 MeV and 300 kGy was characterized by the analysis of the surface morphology, film hardness, adhesion and chemical stability. The mechanical property of thick film, especially film hardness, is better than that of thermal annealed samples at 180 .deg. C. As a result, e-beam annealing process will be one of candidate and attractive heat treatment process. In future, manufacturing process will be carried out in cooperation with the magnet company

  11. Multiphase Simulated Annealing Based on Boltzmann and Bose-Einstein Distribution Applied to Protein Folding Problem

    Directory of Open Access Journals (Sweden)

    Juan Frausto-Solis

    2016-01-01

    Full Text Available A new hybrid Multiphase Simulated Annealing Algorithm using Boltzmann and Bose-Einstein distributions (MPSABBE is proposed. MPSABBE was designed for solving the Protein Folding Problem (PFP instances. This new approach has four phases: (i Multiquenching Phase (MQP, (ii Boltzmann Annealing Phase (BAP, (iii Bose-Einstein Annealing Phase (BEAP, and (iv Dynamical Equilibrium Phase (DEP. BAP and BEAP are simulated annealing searching procedures based on Boltzmann and Bose-Einstein distributions, respectively. DEP is also a simulated annealing search procedure, which is applied at the final temperature of the fourth phase, which can be seen as a second Bose-Einstein phase. MQP is a search process that ranges from extremely high to high temperatures, applying a very fast cooling process, and is not very restrictive to accept new solutions. However, BAP and BEAP range from high to low and from low to very low temperatures, respectively. They are more restrictive for accepting new solutions. DEP uses a particular heuristic to detect the stochastic equilibrium by applying a least squares method during its execution. MPSABBE parameters are tuned with an analytical method, which considers the maximal and minimal deterioration of problem instances. MPSABBE was tested with several instances of PFP, showing that the use of both distributions is better than using only the Boltzmann distribution on the classical SA.

  12. Positron annihilation spectroscopy study on annealing effect of CuO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jianjian; Wang, Jiaheng; Yang, Wei; Zhu, Zhejie; Wu, Yichu, E-mail: ycwu@whu.edu.cn [School of Physics and Technology, Hubei Key Laboratory of Nuclear Solid State Physics, Wuhan University (WHU), Wuhan (China)

    2016-03-15

    The microstructure and defects of CuO nanoparticles under isochronal annealing were investigated by positron annihilation spectroscopy (PAS), X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM results indicated that the average grain sizes of CuO nanoparticles grew slowly below 800 °C, and then increased rapidly with the annealing temperature from 800 to 1000 °C. Positron lifetime analysis exhibited that positrons were mainly annihilated in mono-vacancies (V{sub Cu}, V{sub O}) and vacancy clusters when annealing from 200 to 800 °C. Furthermore, W-S plot of Doppler broadening spectra at different annealing temperatures found that the (W, S) points distributed on two different defect species, which suggested that V{sup −}{sub Cu} - V{sup +}{sub O} complexes were produced when the grains grew to bigger size after annealing above 800 °C, and positrons might annihilate at these complexes. (author)

  13. Annealing of radiation damage in 0.1- and 2-ohm-centimeter Silicon solar cells

    Science.gov (United States)

    Weinberg, I.; Swartz, C. K.

    1979-01-01

    Isochronal and isothermal annealing studies were conducted on 0.1 and 2 ohm centimeter n(+)/p silicon cells after irradiation by 1 MeV electrons at fluences of 10 to the 14th power, 5 times 10 to the 14th power, and 10 to the 15th power per square centimeter. For the 0.1 ohm centimeter cells, reverse annealing was not observed in the isochronal data. However, reverse annealing was observed between approximately 200 and 325 C in the isochronal data of the 2 ohm centimeter cells. Isothermal annealing of 0.1 ohm centimeter cells at 500 C restored pre-irradiation maximum power P sub max within 20 minutes at fluence = 10 to the 14th power, in 180 minutes at fluence = 5 times 10 to the 14th power and to 92 percent of pre-irradiation P sub max in 180 minutes for fluence = 10 to the 15th power. Annealing at 450 C was found inadequate to restore 0.1 ohm centimeter cell performance within reasonable times for all fluence levels. By comparison, at 450 C, the P sub max of 2 ohm centimeter cells was restored within 45 minutes, for the two highest fluence levels, while for the lowest fluence, restoration was completed within 15 minutes. Spectral response data indicate that, for both resistivities, degradation occurs predominantly in the cells p-type base region.

  14. High Temperature Annealing Studies on the Piezoelectric Properties of Thin Aluminum Nitride Films

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, R.; Pagan, V.R.; Kabulski, A.; Kuchibhatla, S.; Harman, J.; Kasarla, K.R.; Rodak, L.E.; Hensel, J.P.; Famouri, P.; Korakakis, D.

    2008-01-01

    A Rapid Thermal Annealing (RTA) system was used to anneal sputtered and MOVPE-grown Aluminum Nitride (AlN) thin films at temperatures up to 1000°C in ambient and controlled environments. According to Energy Dispersive X-Ray Analysis (EDAX), the films annealed in an ambient environment rapidly oxidize after five minutes at 1000°C. Below 1000°C the films oxidized linearly as a function of annealing temperature which is consistent with what has been reported in literature [1]. Laser Doppler Vibrometry (LDV) was used to measure the piezoelectric coefficient, d33, of these films. Films annealed in an ambient environment had a weak piezoelectric response indicating that oxidation on the surface of the film reduces the value of d33. A high temperature furnace has been built that is capable of taking in-situ measurements of the piezoelectric response of AlN films. In-situ d33 measurements are recorded up to 300°C for both sputtered and MOVPE-grown AlN thin films. The measured piezoelectric response appears to increase with temperature up to 300°C possibly due to stress in the film.

  15. High Temperature Annealing Studies on the Piezoelectric Properties of Thin Aluminum Nitride Films

    Energy Technology Data Exchange (ETDEWEB)

    R. Farrell; V. R. Pagan; A. Kabulski; Sridhar Kuchibhatl; J. Harman; K. R. Kasarla; L. E. Rodak; P. Famouri; J. Peter Hensel; D. Korakakis

    2008-05-01

    A Rapid Thermal Annealing (RTA) system was used to anneal sputtered and MOVPE grown Aluminum Nitride (AlN) thin films at temperatures up to 1000°C in ambient and controlled environments. According to Energy Dispersive X-Ray Analysis (EDAX), the films annealed in an ambient environment rapidly oxidize after five minutes at 1000°C. Below 1000°C the films oxidized linearly as a function of annealing temperature which is consistent with what has been reported in literature [1]. Laser Doppler Vibrometry (LDV) was used to measure the piezoelectric coefficient, d33, of these films. Films annealed in an ambient environment had a weak piezoelectric response indicating that oxidation on the surface of the film reduces the value of d33. A high temperature furnace has been built that is capable of taking in-situ measurements of the piezoelectric response of AlN films. In-situ d33 measurements are recorded up to 300°C for both sputtered and MOVPE-grown AlN thin films. The measured piezoelectric response appears to increase with temperature up to 300°C possibly due to stress in the film.

  16. Annealing effects and DLTS study on NPN silicon bipolar junction transistors irradiated by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chaoming; Li, Xingji, E-mail: lxj0218@hit.edu.cn; Yang, Jianqun; Rui, Erming

    2014-01-21

    Isochronal anneal sequences have been carried out on 3DG112 silicon NPN bipolar junction transistors (BJTs) irradiated with 20 MeV bromine (Br) heavy ions. The Gummel curve is utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. We find that the base current (I{sub B}) decreases with the increasing annealing temperature, while the collector current (I{sub C}) remains invariable. The current gain varies slightly, when the annealing temperature (T{sub A}) is lower than 400 K, while varies rapidly at T{sub A}<450 K, and the current gain of the 3DG112 BJT annealing at 700 K almost restore to that of the pre-radiation transistor. Deep level transient spectroscopy (DLTS) data is used to assign the relative magnitude of each of the important defects. Based on the in situ electrical measurement and DLTS spectra, it is clear that the V{sub 2}(−/0)+V-P traps are the main contribution to the degradation of current gain after the 20 MeV Br ions irradiation. The V{sub 2}(−/0)+V-P peak has many of the characteristics expected for the current gain degradation.

  17. Annealing effects and DLTS study on NPN silicon bipolar junction transistors irradiated by heavy ions

    Science.gov (United States)

    Liu, Chaoming; Li, Xingji; Yang, Jianqun; Rui, Erming

    2014-01-01

    Isochronal anneal sequences have been carried out on 3DG112 silicon NPN bipolar junction transistors (BJTs) irradiated with 20 MeV bromine (Br) heavy ions. The Gummel curve is utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. We find that the base current (IB) decreases with the increasing annealing temperature, while the collector current (IC) remains invariable. The current gain varies slightly, when the annealing temperature (TA) is lower than 400 K, while varies rapidly at TABJT annealing at 700 K almost restore to that of the pre-radiation transistor. Deep level transient spectroscopy (DLTS) data is used to assign the relative magnitude of each of the important defects. Based on the in situ electrical measurement and DLTS spectra, it is clear that the V2(-/0)+V-P traps are the main contribution to the degradation of current gain after the 20 MeV Br ions irradiation. The V2(-/0)+V-P peak has many of the characteristics expected for the current gain degradation.

  18. Simulated Stochastic Approximation Annealing for Global Optimization With a Square-Root Cooling Schedule

    KAUST Repository

    Liang, Faming

    2014-04-03

    Simulated annealing has been widely used in the solution of optimization problems. As known by many researchers, the global optima cannot be guaranteed to be located by simulated annealing unless a logarithmic cooling schedule is used. However, the logarithmic cooling schedule is so slow that no one can afford to use this much CPU time. This article proposes a new stochastic optimization algorithm, the so-called simulated stochastic approximation annealing algorithm, which is a combination of simulated annealing and the stochastic approximation Monte Carlo algorithm. Under the framework of stochastic approximation, it is shown that the new algorithm can work with a cooling schedule in which the temperature can decrease much faster than in the logarithmic cooling schedule, for example, a square-root cooling schedule, while guaranteeing the global optima to be reached when the temperature tends to zero. The new algorithm has been tested on a few benchmark optimization problems, including feed-forward neural network training and protein-folding. The numerical results indicate that the new algorithm can significantly outperform simulated annealing and other competitors. Supplementary materials for this article are available online.

  19. Enhanced magnetic refrigeration properties in Mn-rich Ni-Mn-Sn ribbons by optimal annealing

    Science.gov (United States)

    Zhang, Yu; Zhang, Linlin; Zheng, Qiang; Zheng, Xinqi; Li, Ming; Du, Juan; Yan, Aru

    2015-01-01

    The influence of annealing time on temperature range of martensitic phase transition (ΔTA-M), thermal hysteresis (ΔThys), magnetic hysteresis loss (ΔMhys), magnetic entropy change (ΔSM) and relative refrigeration capacity (RC) of the Mn-rich Ni43Mn46Sn11 melt spun ribbons have been systematically studied. By optimal annealing, an extremely large ΔSM of 43.2 J.kg−1K−1 and a maximum RC of 221.0 J.kg−1 could be obtained respectively in a field change of 5 T. Both ΔTA-M and ΔThys decreases after annealing, while ΔMhys and ΔSM first dramatically increase to a maximum then degenerates as increase of annealing time. A large effective cooling capacity (RCeff) of 115.4 J.kg−1 was achieved in 60 min annealed ribbons, which increased 75% compared with that unannealed ribbons. The evolution of magnetic properties and magnetocaloric effect has been discussed and proved by atomic ordering degree, microstructure and composition analysis. PMID:26055884

  20. Structural changes induced by thermal annealing in Cr/C multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Yuchun [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Zhu, Jingtao, E-mail: jtzhu@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Li, Haochuan [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Jonnard, Philippe; Le Guen, Karine; André, Jean-Michel [Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Chen, Hong [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Wang, Zhanshan, E-mail: wangzs@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

    2014-09-15

    Highlights: • We reported experimental results on thermal effects of Cr/C multilayer. • The period thicknesses of Cr/C multilayers expand or contract with different carbon layer thickness ratios upon 600 °C annealing. • More chromium carbide formed at the interfaces after annealing. - Abstract: The structural changes induced by thermal annealing in Cr/C multilayers were investigated. Cr/C multilayers with period thickness of 5 nm and bi-layer number of 30 were deposited by direct current magnetron sputtering, and characterized by using grazing incidence X-ray reflectivity, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results suggest that the period thicknesses of Cr/C multilayers expand or contract with different carbon layer thickness ratios (the ratio of the carbon layer thickness to the multilayer period) upon annealing and the physical mechanism was explored in detail. Carbon layer in Cr/C multilayers become graphitized from amorphous state. Such graphitization of the carbon layer causes a decrease in its density, thus an increase in its thickness. The annealing process also causes a reduction in period due to the formation of denser carbide, which can be confirmed by the XPS results.

  1. Raman Spectroscopy Study of Annealing-Induced Effects on Graphene Prepared by Micromechanical Exfoliation

    International Nuclear Information System (INIS)

    Song, Ji Eun; Ko, Taeg Yeoung; Ryu, Sun Min

    2010-01-01

    Raman spectroscopy was combined with AFM to investigate the effects of thermal annealing on the graphene samples prepared by the widely used micromechanical exfoliation method. Following annealing cycles, adhesive residues were shown to contaminate graphene sheets with thin molecular layers in their close vicinity causing several new intense Raman bands. Detailed investigation shows that the Raman scattering is very strong and may be enhanced by the interaction with graphene. Although the current study does not pinpoint detailed origins for the new Raman bands, the presented results stress that graphene prepared by the above method may require extra cautions when treated with heat or possibly solvents. Since its isolation from graphite, graphene has drawn a lot of experimental and theoretical research. These efforts have been mostly in pursuit of various applications such as electronics, sensors, stretchable transparent electrodes, and various composite materials. To accomplish such graphene-based applications, understanding chemical interactions of this new material with environments during various processing treatments will become more important. Since thermal annealing is widely used in various research of graphene for varying purposes such as cleaning, nanostructuring, reactions, etc., understanding annealing-induced effects is prerequisite to many fundamental studies of graphene. In this regard, it is to be noted that there has been a controversy on the cause of the annealing-induced hole doping in graphene

  2. Tailoring structures through two-step annealing process in nanostructured aluminum produced by accumulative roll-bonding

    DEFF Research Database (Denmark)

    Kamikawa, Naoya; Huang, Xiaoxu; Hansen, Niels

    2008-01-01

    Due to structural and textural heterogeneities and a high content of stored energy, annealing of nanostructured metals is difficult to control in order to avoid non-uniform coarsening and recrystallization. The present research demonstrates a method to homogenize the structure by annealing at low.......8) by accumulative roll-bonding at room temperature. Isochronal annealing for 0.5 h of the deformed samples shows the occurrence of recrystallization at 200 °C and above. However, when introducing an annealing step for 6 h at 175 °C, no significant recrystallization is observed and relatively homogeneous structures...

  3. Temperature sensing based on multimodal interference in polymer optical fibers: Room-temperature sensitivity enhancement by annealing

    Science.gov (United States)

    Kawa, Tomohito; Numata, Goki; Lee, Heeyoung; Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2017-07-01

    To date, we have developed a temperature sensor based on multimodal interference in a polymer optical fiber (POF) with an extremely high sensitivity. Here, we experimentally evaluate the influence of annealing (heat treatment) of the POF on the temperature sensitivity at room temperature. We show that the temperature sensitivity is enhanced with increasing annealing temperature, and that, by annealing the POF at 90 °C, we can achieve a temperature sensitivity of +2.17 nm/°C, which is 2.9 times larger than that without annealing (+0.75 nm/°C).

  4. Effect of annealing process in TiO2 thin films: Structural, morphological, and optical properties

    Science.gov (United States)

    Dussan, A.; Bohórquez, A.; Quiroz, Heiddy P.

    2017-12-01

    This work presents a study of the structural, morphological, and optical properties of titanium dioxide thin films prepared via chemical bath deposition method, after being submitted to annealing processes varying the temperature from 373 to 723 K. The presence of the Rutile phase in all the samples was identified using X-ray diffraction measurements. When the annealing temperature increased to 723 K, the presence of the Anatase phase was observed. From scanning electron microscopy measurements, the formation of nanoflowers was also perceived; these flower-like structures are composed of nanorods of around ∼10 nm in length. With increasing annealing temperature, these structures disappear trans-forming into platelets distributed over the whole surface. A gap energy (Eg) of 3.0 eV was determined, and this value decreased to 2.98 eV after the temperature of T = 723 K was implemented, which is also where the Anatase phase was observed.

  5. Effect of magnetic field annealing on microstructure and magnetic properties of FePt films

    International Nuclear Information System (INIS)

    Li, Y.B.; Lou, Y.F.; Zhang, L.R.; Ma, B.; Bai, J.M.; Wei, F.L

    2010-01-01

    FePt (20 nm) films were annealed in a magnetic field (along the normal direction of the films) at a temperature around the Curie temperature of L1 0 FePt. The influence of magnetic filed annealing on texture and magnetic properties of FePt films were investigated. The results indicate that preferential (0 0 1) orientation and perpendicular anisotropy can be obtained in L1 0 FePt films by using magnetic field annealing around the Curie temperature of L1 0 FePt. This is one of the potential methods to obtain (0 0 1) orientation and thus to improve the perpendicular anisotropy in FePt films.

  6. Annealing studies of Zircaloy-2 cladding at 580-850 deg C

    International Nuclear Information System (INIS)

    Hindle, E.D.

    1983-01-01

    For fuel rod cladding it is important to determine if prior metallurgical condition combined with irradiation damage can influence high temperature deformation, because studies of such deformation are required to produce data for the cladding ballooning models which are used in analysing loss-of-coolant (LOCA). If the behaviour of all cladding conditions during a LOCA can be represented by, say, the annealed condition, then a great deal of experimental work on a multiplicity of cladding conditions can be avoided. By examining the metallographic structure and hardness, the present study determines the time required in the range 580 to 850 deg C for returning Zircaloy cladding to the annealed condition, so that for any transient a point can be specified where the material should have annealed. An equation has been derived to give this information. (author)

  7. Effects of cold worked and fully annealed claddings on fuel failure behaviour

    International Nuclear Information System (INIS)

    Saito, Shinzo; Hoshino, Hiroaki; Shiozawa, Shusaku; Yanagihara, Satoshi

    1979-12-01

    Described are the results of six differently heat-treated Zircaloy clad fuel rod tests in NSRR experiments. The purpose of the test is to examine the extent of simulating irradiated claddings in mechanical properties by as-cold worked ones and also the effect of fully annealing on the fuel failure bahaviour in a reactivity initiated accident (RIA) condition. As-cold worked cladding does not properly simulated the embrittlement of the irradiated one in a RIA condition, because the cladding is fully annealed before the fuel failure even in the short transient. Therefore, the fuel behaviour such as fuel failure threshold energy, failure mechanism, cladding deformation and cladding oxidation of the fully annealed cladding fuel, as well as that of the as-cold worked cladding fuel, are not much different from that of the standard stress-relieved cladding fuel. (author)

  8. Annealing Behavior of Al-Implantation-Induced Disorder in 4H-SiC

    International Nuclear Information System (INIS)

    Zhang, Yanwen; Weber, William J.; Jiang, Weilin; Shutthanandan, V.; Thevuthasan, Suntharampillai; Janson, Martin; Hallen, Anders

    2004-01-01

    Single crystal 4H-SiC films were implanted at 150 K with 1.1 MeV Al 2 2+ and subsequently annealed at elevated temperatures. Rutherford backscattering spectrometry (RBS) results indicate that the relative Si disorder at the damage peak recovers significantly as the annealing temperature increases. However, the residual Si disorder is more resistant to high-temperature annealing in the region of the implanted Al. The maximum concentration of Al profile measured by secondary ion mass spectroscopy (SIMS) is a factor of 1000 lower than the level of the residual Si disorder at the same region. Analysis of these results indicates that the excess residual Si disorder around the implanted Al projected range cannot be accounted for by just the Al interstitials; instead, it appears that each implanted Al stabilizes or inhibits recovery for an equivalent of a few hundred Si interstitials under the current experimental conditions

  9. Sensitization of erbium in silicon-rich silica : the effect of annealing temperature and hydrogen passivation

    International Nuclear Information System (INIS)

    Wilkinson, A.R.; Forcales, M.; Elliman, R.G.

    2005-01-01

    This paper reports on the effect of annealing temperature and hydrogen passivation on the excitation cross-section and photoluminescence of erbium in silicon-rich silica. Samples were prepared by co-implantation of Si and Er into SiO 2 followed by a single thermal anneal at temperatures ranging from 800 to 1100 degrees C, and with or without hydrogen passivation performed at 500 degrees C. Using time-resolved photoluminescence, the effective erbium excitation cross-section is shown to increase by a factor 3, while the number of optically active erbium ions decreases by a factor of 4 with increasing annealing temperature. Hydrogen passivation is shown to increase the luminescence intensity and to shorten the luminescence lifetime at 1.54 μm only in the presence of Si nanocrystals. The implications fo these results for realizing a silicon-based optical amplifier are also discussed. (author). 19 refs., 3 figs

  10. Towards p-type ZnO using post-growth annealing

    Energy Technology Data Exchange (ETDEWEB)

    Dangbegnon, J.K.; Roro, K.T.; Botha, J.R. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2008-01-15

    The optical properties of zinc oxide (ZnO) films grown by metalorganic chemical vapor deposition on GaAs substrate are investigated. Samples were annealed in two different ambients, namely nitrogen and oxygen, and studied by photoluminescence (PL). Samples annealed in oxygen at 600 C show arsenic acceptor-related signatures. The near-band-edge emission is dominated by an excitonic feature at 3.355 eV and compensation broadens the spectra. No such changes are observed when similar samples are annealed in nitrogen. The diffusion of arsenic from the GaAs substrate appears to be a source of acceptors. This effect is enhanced in an oxygen atmosphere. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Evolution Law of Helium Bubbles in Hastelloy N Alloy on Post-Irradiation Annealing Conditions

    Directory of Open Access Journals (Sweden)

    Jie Gao

    2016-10-01

    Full Text Available This work reports on the evolution law of helium bubbles in Hastelloy N alloy on post-irradiation annealing conditions. After helium ion irradiation at room temperature and subsequent annealing at 600 °C (1 h, the transmission electron microscopy (TEM micrograph indicates the presence of helium bubbles with size of 2 nm in the depth range of 0–300 nm. As for the sample further annealed at 850 °C (5 h, on one hand, a “Denuded Zone” (0–38 nm with rare helium bubbles forms due to the decreased helium concentration. On the other hand, the “Ripening Zone” (38–108 nm and “Coalescence Zone” (108–350 nm with huge differences in size and separation of helium bubbles, caused by different coarsening rates, are observed. The mechanisms of “Ostwald ripening” and “migration and coalescence”, experimentally proved in this work, may explain these observations.

  12. Influence of the implantation and annealing parameters on the photoluminescence produced by Si hot implantation

    Energy Technology Data Exchange (ETDEWEB)

    Sias, U.S. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil) and Centro Federal de Educacao Tecnologica de Pelotas (CEFET-RS), 96015-370 Pelotas, RS (Brazil)]. E-mail: uilson@cefetrs.tche.br; Behar, M. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Boudinov, H. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Moreira, E.C. [UFPel - UNIPAMPA, Campus Bage, 96400-970 Bage, RS (Brazil)

    2007-04-15

    We report an investigation on the effect of the fluence and annealing time on the photoluminescence (PL) from Si nanocrystals produced by hot implantation of Si into a SiO{sub 2} matrix followed by thermal treatment in nitrogen. We have varied the implantation fluence in a wide range, from 0.35 x 10{sup 17} to 4 x 10{sup 17} Si/cm{sup 2}. In addition, the PL evolution with the annealing time (1 up to 15 h) was studied for the samples implanted with fluences between 1 x 10{sup 17} and 4 x 10{sup 17} Si/cm{sup 2}. After annealing the spectra present two PL bands: one centered at 780 nm and a second one around 1000 nm. The influence of the studied parameters on the PL behavior of both bands suggests different origins for their emission. The results are discussed in terms of current models.

  13. Thermal defect annealing of swift heavy ion irradiated ThO2

    Science.gov (United States)

    Palomares, Raul I.; Tracy, Cameron L.; Neuefeind, Joerg; Ewing, Rodney C.; Trautmann, Christina; Lang, Maik

    2017-08-01

    Isochronal annealing, neutron total scattering, and Raman spectroscopy were used to characterize the structural recovery of polycrystalline ThO2 irradiated with 2-GeV Au ions to a fluence of 1 × 1013 ions/cm2. Neutron diffraction patterns show that the Bragg signal-to-noise ratio increases and the unit cell parameter decreases as a function of isochronal annealing temperature, with the latter reaching its pre-irradiation value by 750 °C. Diffuse neutron scattering and Raman spectroscopy measurements indicate that an isochronal annealing event occurs between 275-425 °C. This feature is attributed to the annihilation of oxygen point defects and small oxygen defect clusters.

  14. Recombination luminescence in irradiated silicon - Effects of thermal annealing and lithium impurity.

    Science.gov (United States)

    Johnson, E. S.; Compton, W. D.

    1971-01-01

    Use of luminescence in irradiated silicon to determine the thermal stability of the defects responsible for the recombination. It is found that the defect responsible for the zero-phonon line at 0.97 eV has an annealing behavior similar to that of the divacancy and that the zero-phonon line at 0.79 eV anneals in a manner similar to the G-15 or K-center. Annealing at temperatures up to 500 C generates other defects whose luminescence is distinct from that seen previously. Addition of lithium to the material produces defects with new characteristic luminescence. Of particular importance is a defect with a level at E sub g -1.045 eV.

  15. Liquid nitrogen enhancement of partially annealed fission tracks in glass; and reply

    International Nuclear Information System (INIS)

    Wagner, G.A.; Carpenter, B.S.; Pilione, L.J.; Gold, D.P.

    1977-01-01

    Pilione and Gold (Nature 262: 773 (1976)) stated that it was possible to reveal partially annealed fission tracks in glass by immersion in liquid N 2 , and that it was possible to increase the total number of etchable tracks by increasing the immersion time. The present authors attempted to duplicate the work of the former authors using the same glass. They found no significant change in the number of etchable tracks after immersion in liquid N 2 , and they concluded that the latter has no effect on annealed tracks in glass. Any observed enhancement of partially annealed tracks is probably a surface effect and has no effect on the interior matrix of the glass. A reply by Pilione and Gold is appended. (U.K.)

  16. Thermal annealing effects on non-peripheral octahexylphthalocyanine doped polymer bulk heterojunction solar cells

    Science.gov (United States)

    De Romeo Banoukepa, Gilles; Masuda, Tetsuya; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2014-01-01

    We investigated the thermal annealing temperature dependence of the photovoltaic properties of organic thin film solar cells based on a bulk heterojunction of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxy-carbonyl)-propyl-1-1-phenyl-(6,6)C61 (PCBM) doped with the soluble phthalocyanine derivative 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2). The photocurrent density was increased by 45% and the power conversion efficiency was improved to 3.9% by annealing at 130 °C. The annealing temperature dependence of the photovoltaic properties is discussed by considering the result of X-ray diffraction and photoluminescence measurements.

  17. Annealing studies of zircaloy-2 cladding at 580-8500C

    International Nuclear Information System (INIS)

    Hindle, E.D.

    1978-05-01

    For fuel element cladding it is important to determine if prior metallurgical condition combined with irradiation damage can influence high temperature deformation, because studies of such deformation are required to produce data for the cladding ballooning models which are used in analysing loss-of-coolant accidents (LOCA). If the behaviour of all cladding conditions during a LOCA can be represented by, say, the annealed condition, then much experimental work on a multiplicity of cladding conditions can be avoided. By examining the metallographic structure and hardness, the present study determines the time required in the range 580 to 850 0 C for returning Zircaloy cladding to the annealed condition, so that for any transient, a point can be specified where the material should have annealed. An equation has been derived to give this information. (author)

  18. An Enhanced Differential Evolution Based Algorithm with Simulated Annealing for Solving Multiobjective Optimization Problems

    Directory of Open Access Journals (Sweden)

    Bili Chen

    2014-01-01

    Full Text Available An enhanced differential evolution based algorithm, named multi-objective differential evolution with simulated annealing algorithm (MODESA, is presented for solving multiobjective optimization problems (MOPs. The proposed algorithm utilizes the advantage of simulated annealing for guiding the algorithm to explore more regions of the search space for a better convergence to the true Pareto-optimal front. In the proposed simulated annealing approach, a new acceptance probability computation function based on domination is proposed and some potential solutions are assigned a life cycle to have a priority to be selected entering the next generation. Moreover, it incorporates an efficient diversity maintenance approach, which is used to prune the obtained nondominated solutions for a good distributed Pareto front. The feasibility of the proposed algorithm is investigated on a set of five biobjective and two triobjective optimization problems and the results are compared with three other algorithms. The experimental results illustrate the effectiveness of the proposed algorithm.

  19. Relaxation of enthalpy fluctuations during sub-T(g) annealing of glassy selenium.

    Science.gov (United States)

    Gulbiten, Ozgur; Mauro, John C; Lucas, Pierre

    2013-06-28

    The relaxation behavior of glass is influenced by the presence of dynamical heterogeneities, which lead to an intrinsically non-monotonic decay of fluctuations in density and enthalpy during isothermal annealing. This is apparently a universal feature of fragile glass forming systems associated with localized spatial variations in relaxation time. Here we present direct experimental observation of the nonmonotonic evolution of enthalpy fluctuations in glassy selenium annealed near room temperature. The nonmonotonic change in the distribution of enthalpy fluctuations measured by heat capacity spectroscopy offers direct evidence for the presence of dynamical heterogeneity in this glass. An enthalpy landscape model of selenium is then used to simulate annealing under identical conditions. The simulation results closely follow the evolution of enthalpy fluctuations observed experimentally. The close match between model and experiment demonstrate that enthalpy and density fluctuations are sources of dynamical heterogeneities in glassy materials.

  20. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... telecommunication. However, silicon clustering appears in the thin films when annealing above 1150 oC. Clustering is undesirable in waveguide materials because the localized variations of the refractive index associated with the clusters lead to Raleigh scattering, which can cause significant propagation loss...... investigated by Rutherford back scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The influence of deposition parameters and annealing temperatures on the stoichiometry and the chemical bonds will be discussed. The origin of the clusters has been found to be silicon due to severe silicon out...

  1. Barium strontium titanate (BST) thin film analysis on different layer and annealing temperature

    Science.gov (United States)

    Teh, Y. C.; Ong, N. R.; Sauli, Z.; Alcain, J. B.; Retnasamy, V.

    2017-09-01

    Barium Strontium Titanate (BST) thin film has been prepared by using sol-gel method. The samples are prepared with 2 different deposition layers (1 layer and 4 layer) and annealing temperature (600°C and 800°C) with Ba0.5Sr0.5TiO3 solution. Physical and electrical characterization of all the samples is done. The results showed that the grain size and surface roughness of the samples increased as the deposition layer and annealing temperature increased. In addition, the dielectric constant of the samples also increased as the deposition layer and annealing temperature increased. Thus, the physical and electrical characteristics of the thin films are related one to another.

  2. Transmission electron microscope studies of laser and thermally annealed ion implanted silicon

    International Nuclear Information System (INIS)

    Narayan, J.; Young, R.T.; White, C.W.

    1978-01-01

    Transmission electron microscopy has been used to study the effects of high power laser pulses on boron, phosphorous and arsenic implanted [100] silicon crystals. No defects (dislocations, dislocation loops and/or stacking faults) were observed in either as-grown or implanted silicon after one pulse of ruby laser irradiation (lambda = 0.694 μm, pulse energy density 1.5 to 1.8 J cm -2 , 50 x 10 -9 pulse duration time). The concentration of boron in solution, as inferred from electrical measurements, could exceed the equilibrium solubility. In thermally annealed specimens, on the other hand, significant damage remained even after annealing at 1100 0 C for 30 minutes. On thermally annealing the implanted, laser-treated specimens, precipitation of the implanted boron ions occurred whenever the implanted doses were in excess of the equilibrium solubility limits. The relationship of these observations to the results of electrical measurements made on these samples will be discussed

  3. Annealing effect on planar waveguides in LiNbO 3 produced by oxygen ion implantation

    Science.gov (United States)

    Liu, Xiu-Hong; Huang, Qing; Zhao, Jin-Hua; Liu, Peng; Wang, Xue-Lin; Du, Ji-Fu; Huang, Ning-Kang

    2011-01-01

    We reported on planar waveguides in stoichiometric lithium niobate fabricated by 4.5 MeV oxygen ion implantation with a dose of 6 × 10 14 ions/cm 2 at room temperature. After ion implantation, these samples were annealed at 240 °C, 260 °C, and 300 °C for 30 min. We investigated annealing effect on the guiding modes and near-field images in the waveguides by prism-coupling method and end-face coupling method respectively. We found that for the extraordinary refractive index a positive alternation occurred in the near-surface region while a negative alternation happened at the end of ion track. Moreover, we measured the transmission spectra for the pure sample and implanted samples before and after annealed at different temperatures, and we observed an absorption peak at ˜480 nm (2.6 eV) in all of these SLN samples.

  4. Growth of monodisperse nanocrystals of cerium oxide during synthesis and annealing

    International Nuclear Information System (INIS)

    Ghosh, Swapankumar; Divya, Damodaran; Remani, Kottayilpadi C.; Sreeremya, Thadathil S.

    2010-01-01

    Monodisperse cerium oxide nanocrystals have been successfully synthesised using simple ammonia precipitation technique from cerium(III) nitrate solution at different temperatures in the range 35-80 o C. The activation energy for growth of CeO 2 nanocrystals during the precipitation is calculated as 11.54 kJ/mol using Arrhenius plot. Average crystal diameter was obtained from XRD analysis, HR-TEM and light scattering (PCS). The analysis of size data from HR-TEM images and PCS clearly indicated the formation of highly crystalline CeO 2 particles in narrow size range. CeO 2 nanocrystals precipitated at 35 o C were further annealed at temperatures in the range 300-700 o C. The activation energy for crystal growth during annealing is also calculated and is close to the reported values. An effort is made to predict the mechanism of crystal growth during the precipitation and annealing.

  5. Tribological properties of the Fe-Al intermetallic alloys after annealing

    Directory of Open Access Journals (Sweden)

    K. Garbala

    2011-04-01

    Full Text Available In paper researching results of tribological proprieties Fe3Al intermetallic alloys after annealing are presented. Studies were conducted in the following environments: a water; an air and oil. For investigation purposes the tribotester pin-on-disk type with the contrsample made of steel 40H quenched and tempered was used. Tests were carried out with the following process parameters: pressure p = 2MPa and linear velocity (circuital V = 0.46m/s. It was noted, that intermetallic samples with the small distinction in chemical compositions, annealed at different temperatures showed a large difference in the quantity of material loss in the all tested environments. Appropriately selected parameters of the intermetallic alloys annealing, provide their greater resistance to abrasion in the air and oil environments than in the case of steel.

  6. Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure

    Science.gov (United States)

    Jessadaluk, S.; Khemasiri, N.; Rahong, S.; Rangkasikorn, A.; Kayunkid, N.; Wirunchit, S.; Horprathum, M.; Chananonnawathron, C.; Klamchuen, A.; Nukeaw, J.

    2017-09-01

    This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (VxOy) thin films by post-thermal annealing process. Usually, as-deposited VxOy thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N2) pressures are applied to improve and control the crystal phase of VxOy thin films. The crystallinity of VxOy thin films changes from amorphous to α-V2O5 phase or V9O17 polycrystalline, which depend on the pressure of N2 carrier during annealing process. Moreover, the electrical resistivity of the VxOy thin films decrease from 105 Ω cm (amorphous) to 6×10-1 Ω cm (V9O17). Base on the results, our study show a simply method to improve and control phase formation of VxOy thin films.

  7. Effect of annealing on bulk heterojunction organic solar cells based on copper phthalocyanine and perylene derivative

    KAUST Repository

    Kim, Inho

    2012-02-01

    We investigated the effects of annealing on device performances of bulk heterojunction organic solar cells based on copper phthalocyanine (CuPc) and N,N′-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C6). Blended films of CuPc and PTCDI-C6 with annealing at elevated temperature were characterized by measuring optical absorption, photoluminescence, and X-ray diffraction. Enhanced molecular ordering and increments in domain sizes of donor and acceptor for the blended films were observed, and their influences on device performances were discussed. Annealing led to substantial improvements in photocurrent owing to enhanced molecular ordering and formation of percolation pathways. © 2011 Elsevier B.V. All rights reserved.

  8. High reflectivity Ohmic contacts to n-GaN utilizing vacuum annealed aluminum

    KAUST Repository

    Yonkee, Benjamin P.

    2017-10-31

    Ohmic contacts to both c-plane and (202 ̅1 ̅) n-GaN are demonstrated using a pure aluminum layer which was vacuum annealed to prevent oxidation. Specific contact resistivities of 4.4 × 10-7 and 2.3 × 10-5 Ωcm2 were obtained without annealing for c-plane and (202 ̅1 ̅ ) samples respectively. A reflectivity of over 85% at 450 nm was measured for both samples. After a 300 °C anneal specific contact resistivities of 1.5 × 10-7 and 1.8 × 10-7 Ωcm2 were obtained for c-plane and (202 ̅1 ̅ ) samples respectively and the reflectivities remained higher than 80%.

  9. Annealing effect of H+ -implanted single crystal silicon on strain and crystal structure

    International Nuclear Information System (INIS)

    Duo Xinzhong; Liu Weili; Zhang Miao; Gao Jianxia; Fu Xiaorong; Lin Chenglu

    2000-01-01

    The work focuses on the rocking curves of H + -implanted single silicon crystal detected by Four-Crystal X-ray diffractometer. The samples were annealed under different temperatures. Lattice defect in H + -implanted silicon crystals was detected by Rutherford Backscattering Spectrometry. It appeared that H-related complex did not crush until annealing temperature reached about 400 degree C. At that temperature H 2 was formed, deflated in silicon lattice and strained the lattice. But defects did not come into being in large quantity. The lattice was undamaged. When annealing temperature reached 500 degree C, strain induced by H 2 deflation crashed the silicon lattice. A large number of defects were formed. At the same time bubbles in the crystal and blister/flaking on the surface could be observed

  10. Formation and annealing of radiation defects in tin-doped p-type germanium crystals

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, V. V., E-mail: aif-minsk@ibb.by; Petukh, A. N.; Pokotilo, Ju. M. [Belarussian State University (Belarus); Markevich, V. P.; Lastovskii, S. B. [National Academy of Sciences of Belarus, Scientific and Practical Materials Research Center (Belarus)

    2012-05-15

    The effect of tin on the formation and annealing of radiation defects in p-type germanium crystals irradiated with 6-MeV electrons at a temperature of 80 K is studied. It is shown that acceptor complexes SnV with a hole ionization enthalpy of 0.16 eV are dominant in irradiated Ge:(Sn, Ga) crystals after their heating to a temperature of 300 K. These complexes disappeared as a result of the annealing of irradiated crystals in the temperature range 30-75 Degree-Sign C. Annealing of irradiated crystals at temperatures in the range 110-150 Degree-Sign C brings about the formation of deep-level centers with a donor level at E{sub v} + 0.29 eV; this center is presumably related to a complex consisting of a tin atom and an interstitial gallium atom.

  11. Microstructure and texture evolution of cold-rolled deep-drawing steel sheet during annealing

    Science.gov (United States)

    Zhou, Le-yu; Wu, Lei; Liu, Ya-zheng; Cheng, Xiao-jie; Sun, Jin-hong

    2013-06-01

    In accordance with experimental results about the annealing microstructure and texture of cold-rolled deepdrawing sheet based on the compact strip production (CSP) process, a two-dimensional cellular automation simulation model, considering real space and time scale, was established to simulate recrystallization and grain growth during the actual batch annealing process. The simulation results show that pancaked grains form during recrystallization. {111} advantageous texture components become the main parts of the recrystallization texture. After grain growth, the pancaked grains coarsen gradually. The content of {111} advantageous texture components in the annealing texture increases from 55vol% to 65vol%; meanwhile, the contents of {112} and {100} texture components decrease by 4% and 8%, respectively, compared with the recrystallization texture. The simulation results of microstructure and texture evolution are also consistent with the experimental ones, proving the accuracy and usefulness of the model.

  12. Effect of annealing on the composition of PECVD borosilicate and borophosphosilicate glasses

    Science.gov (United States)

    Osório, S. P. A.; Montero, I.; Perrière, J.; Martinez-Duart, J. M.

    1993-06-01

    Borosilicate, B xSiO z (BSG), and borophosphosilicate, B xP ySiO z (BPSG) glasses, for applications as intermetal dielectrics in VLSI technology were deposited by plasma enhanced chemical vapor deposition on silicon substrates. Quantitative infrared spectroscopy (IR), Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA) and X-ray energy dispersion (EDX) were used to obtain the composition of the films. After annealing at temperatures in the range 200 to 900°C under a nitrogen ambient, the concentration of phosphorus and boron in the deposited films is analyzed. It is found that the phosphorus concentration is independent of the annealing temperature. However, the boron concentration decreases with the annealing temperature in both types of glasses. This effect can be attributed to the influence of the concentration of the P-O bonds in the phosphorus doped films, and also to the morphology and hygroscopicity of the films.

  13. Formation and annealing behaviors of qubit centers in 4H-SiC from first principles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaopeng; Zhao, Mingwen, E-mail: zmw@sdu.edu.cn; Bu, Hongxia; He, Xiujie; Wang, Aizhu [School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100 (China); Zhang, Hongyu [Department of Physics, East China University of Science and Technology, Shanghai 200237 (China)

    2013-11-21

    Inspired by finding that the nitrogen-vacancy center in diamond is a qubit candidate, similar defects in silicon carbide (SiC) have drawn considerable interest. However, the generation and annealing behaviors of these defects remain unclear. Using first-principles calculations, we describe the equilibrium concentrations and annealing mechanisms based on the diffusion of silicon vacancies. The formation energies and energy barriers along different migration paths, which are responsible for the formation rates, stability, and concentrations of these defects, are investigated. The effects on these processes of charge states, annealing temperature, and crystal orientation are also discussed. These theoretical results are expected to be useful in achieving controllable generation of these defects in experiments.

  14. Optimization of pressurized water reactor shuffling by simulated annealing with heuristics

    International Nuclear Information System (INIS)

    Stevens, J.G.; Smith, K.S.; Rempe, K.R.; Downar, T.J.

    1995-01-01

    Simulated-annealing optimization of reactor core loading patterns is implemented with support for design heuristics during candidate pattern generation. The SIMAN optimization module uses the advanced nodal method of SIMULATE-3 and the full cross-section detail of CASMO-3 to evaluate accurately the neutronic performance of each candidate, resulting in high-quality patterns. The use of heuristics within simulated annealing is explored. Heuristics improve the consistency of optimization results for both fast- and slow-annealing runs with no penalty from the exclusion of unusual candidates. Thus, the heuristic application of designer judgment during automated pattern generation is shown to be effective. The capability of the SIMAN module to find and evaluate families of loading patterns that satisfy design constraints and have good objective performance within practical run times is demonstrated. The use of automated evaluations of successive cycles to explore multicycle effects of design decisions is discussed

  15. A crystallographic texture perspective formability investigation of aluminium 5052 alloy sheets at various annealing temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Narayanasamy, R. [Department of Production Engineering, National Institute of Technology, Tiruchirappalli - 620015, Tamilnadu (India); Ravindran, R. [Department of Mechanical Engineering, VLB Janakiammal College of Engineering and Technology, Coimbatore - 641042, Tamilnadu (India)], E-mail: mceravindran@yahoo.co.in; Manonmani, K. [Department of Mechanical Engineering, Government College of Technology, Coimbatore - 641013, Tamilnadu (India)], E-mail: manokmani@yahoo.co.in; Satheesh, J. [Department of Production Engineering, National Institute of Technology, Tiruchirappalli - 620015, Tamilnadu (India)

    2009-05-15

    Formability, an important mechanical property of the sheet metal is strongly reliant on the crystallographic texture. Consequently deep drawability is also influenced. This paper deals with the perspective of crystallographic texture and its relevance with the formability of AA 5052 aluminium alloy sheet of 2 mm thickness annealed at four different temperatures namely 200 deg. C, 250 deg. C, 300 deg. C and 350 deg. C. Forming limit diagrams determined and plotted experimentally, their crystallographic textures obtained and their ODF plots prepared by X-ray diffraction were analyzed. The Forming limit diagrams (FLDs) of AA 5052 sheets annealed under different temperatures were examined with respect to the crystallographic texture point of view. The FLDs and crystallographic textures were then correlated with normal anisotropy of the sheet metal. It was found that the formability of aluminium alloy AA 5052 annealed at 350 deg. C possessed good formability, optimal texture and high normal anisotropy value.

  16. Tailoring magnetic properties of multicomponent layered structure via current annealing in FePd thin films.

    Science.gov (United States)

    Cialone, Matteo; Celegato, Federica; Coïsson, Marco; Barrera, Gabriele; Fiore, Gianluca; Shvab, Ruslan; Klement, Uta; Rizzi, Paola; Tiberto, Paola

    2017-11-30

    Multicomponent layered systems with tailored magnetic properties were fabricated via current annealing from homogeneous Fe 67 Pd 33 thin films, deposited via radio frequency sputtering on Si/SiO2 substrates from composite target. To promote spontaneous nano-structuring and phase separation, selected samples were subjected to current annealing in vacuum, with a controlled oxygen pressure, using various current densities for a fixed time and, as a consequence, different phases and microstructures were obtained. In particular, the formation of magnetite in different amount was observed beside other iron oxides and metallic phases. Microstructures and magnetic properties evolution as a function of annealing current were studied and interpreted with different techniques. Moreover, the temperature profile across the film thickness was modelled and its role in the selective oxidation of iron was analysed. Results show that is possible to topologically control the phases formation across the film thickness and simultaneously tailor the magnetic properties of the system.

  17. Annealing influence on the atomic ordering and magnetic moment in a Ni-Mn-Ga alloy

    International Nuclear Information System (INIS)

    Gutierrez, J.; Lazpita, P.; Barandiaran, J.M.; Fdez-Gubieda, M.L.; Chaboy, J.; Kawamura, N.

    2007-01-01

    We have studied an alloy of composition Ni 51 Mn 28 Ga 21 prepared by rapid quenching in the form of a ribbon, with transformation temperature T M =337 K below the magnetic-order temperature, T C =344 K. Annealing of the samples was performed at 600 K for different times. From magnetic characterization a clear increase of the saturation magnetization accompanied with an increase of T C (up to 20 K) and T M (about 10 K) has been observed. XMCD measurements of both as-quenched and annealed samples have revealed great changes for the Mn and also the existence of a strong Ni signal. These results point out a possible non-negligible role of Ni, through the polarization of the conduction band, into driving the interplay between annealing and the magnetic properties in these materials

  18. Annealing evolutionary stochastic approximation Monte Carlo for global optimization

    KAUST Repository

    Liang, Faming

    2010-04-08

    In this paper, we propose a new algorithm, the so-called annealing evolutionary stochastic approximation Monte Carlo (AESAMC) algorithm as a general optimization technique, and study its convergence. AESAMC possesses a self-adjusting mechanism, whose target distribution can be adapted at each iteration according to the current samples. Thus, AESAMC falls into the class of adaptive Monte Carlo methods. This mechanism also makes AESAMC less trapped by local energy minima than nonadaptive MCMC algorithms. Under mild conditions, we show that AESAMC can converge weakly toward a neighboring set of global minima in the space of energy. AESAMC is tested on multiple optimization problems. The numerical results indicate that AESAMC can potentially outperform simulated annealing, the genetic algorithm, annealing stochastic approximation Monte Carlo, and some other metaheuristics in function optimization. © 2010 Springer Science+Business Media, LLC.

  19. Effect of annealing on magnetic properties and structure of Fe-Ni based magnetic microwires

    International Nuclear Information System (INIS)

    Zhukova, V.; Korchuganova, O.A.; Aleev, A.A.; Tcherdyntsev, V.V.; Churyukanova, M.; Medvedeva, E.V.; Seils, S.; Wagner, J.; Ipatov, M.; Blanco, J.M.; Kaloshkin, S.D.; Aronin, A.; Abrosimova, G.; Orlova, N.

    2017-01-01

    Highlights: • High domain wall mobility of Fe-Ni-based microwires. • Enhancement of domain wall velocity and mobility in Fe-rich microwires after annealing. • Observation of areas enriched by Si and depleted by B after annealing. • Phase separation in annealed Fe-Ni based microwires in metallic nucleus and near the interface layer. - Abstract: We studied the magnetic properties and domain wall (DW) dynamics of Fe 47.4 Ni 26.6 Si 11 B 13 C 2 and Fe 77.5 Si 7.5 B 15 microwires. Both samples present rectangular hysteresis loop and fast magnetization switching. Considerable enhancement of DW velocity is observed in Fe 77.5 Si 7.5 B 15 , while DW velocity of samples Fe 47.4 Ni 26.6 Si 11 B 13 C 2 is less affected by annealing. The other difference is the magnetic field range of the linear region on dependence of domain wall velocity upon magnetic field: in Fe 47.4 Ni 26.6 Si 11 B 13 C 2 sample is considerably shorter and drastically decreases after annealing. We discussed the influence of annealing on DW dynamics considering different magnetoelastic anisotropy of studied microwires and defects within the amorphous state in Fe 47.4 Ni 26.6 Si 11 B 13 C 2 . Consequently we studied the structure of Fe 47.4 Ni 26.6 Si 11 B 13 C 2 sample using X-ray diffraction and the atom probe tomography. The results obtained using the atom probe tomography supports the formation of the B-depleted and Si-enriched precipitates in the metallic nucleus of Fe-Ni based microwires.

  20. Influence of annealing temperature on the Dy diffusion process in NdFeB magnets

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Sheng-qing, E-mail: joy_hsq@126.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Peng, Kun, E-mail: kpeng@hnu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Hong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2017-03-15

    Sintered NdFeB magnets were coated with a layer of Dy metal using electron beam evaporation method and then annealed at various temperatures to investigate the temperature dependence of Dy diffusion process in NdFeB magnets. A Dy-rich phase was observed along the grain boundaries after the grain boundary diffusion process, the diffusion coefficients of various temperatures were obtained, the diffusion coefficients of Dy along the grain boundaries at 800 °C and 900 °C were determined to be 9.8×10{sup −8} cm{sup 2} s{sup −1} and 2.4×10{sup −7} cm{sup 2} s{sup −1}, respectively. The diffusion length depended on the annealing temperature and the maximum diffusion length of approximately 1.8 mm and 3.0 mm can be obtained after annealing at 800 °C and 900 °C for 8 h. Higher diffusion temperature results in the diffusion not only along the grain boundaries but also into grains and then decrease in magnetic properties. The optimum annealing conditions can be determined as 900 °C for 8 h. The coercivity was improved from 1040 kA/m to 1450 kA/m and its magnetization has no significant reduction after the grain boundary diffusion process at the optimum annealing conditions. - Highlights: • The optimum annealing conditions can be determined as 900 °C for 8 h. • The diffusion coefficient of Dy at 900 °Care determined to be 2.4×10{sup −7} cm{sup 2} s{sup −1}. • A maximum diffusion length of about 3 mm can be obtained.

  1. Annealing assisted structural and surface morphological changes in Langmuir–Blodgett films of nickel octabutoxy phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Shilpa Harish, T.; Viswanath, P., E-mail: viswanath@cnsms.res.in

    2016-01-01

    We report our studies on thin films of metallo-phthalocyanine (MPc), Nickel(II)1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (NiPc(OBu){sub 8}) transferred in a well defined thermodynamic state over a self assembled monolayer (octadecyl trichlorosilane)/SiO{sub 2}/Si substrate using the Langmuir–Blodgett (LB) method. The films are characterized using differential scanning calorimetry (DSC), grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) techniques. DSC studies on powdered samples in the bulk indicate enantiotropic solid–solid phase transition. GIXD studies on the as-deposited LB film show a Bragg peak indicating crystallinity of the thin film. Annealing (373 K) results in reduction of lattice spacing (1.21 Å) signifying changes in molecular packing within the unit cell. At this stage, an additional Bragg peak is observed which grows at the expense of the former one and they coexist between 373 K and 423 K. A discontinuity in lattice spacing from 20.73 to 15.12 Å with annealing indicates clearly a structural change of the underlying crystalline lattice. Correspondingly, the surface morphology images obtained using AFM show, with annealing, a transformation from spherical granular morphology to elongated, flat crystallites suggesting asymmetric growth process. Statistical parameters of the grain extracted from the AFM images show that the size, fractal dimension and circularity are affected by annealing. Based on these studies, we infer the structural and surface morphological changes of the meta-stable phase (Form I) to the stable phase (Form II) in annealed LB films of phthalocyanine. - Highlights: • Langmuir–Blodgett (LB) films of phthalocyanine subjected to thermal annealing. • Structural transformation and coexistence of polymorphs in LB films • Surface morphology changes from nanoscale grains to elongated crystallites. • Reduction of fractal dimension and circularity index reveals asymmetric growth.

  2. Rapid capless annealing of28Si,64Zn, and9Be implants in GaAs

    Science.gov (United States)

    Liu, S. G.; Narayan, S. Y.

    1984-11-01

    We report the use of tungsten-halogen lamps for rapid (-10 s) thermal annealing of ion-implanted (100) GaAs under AsH3/Ar and N2 atmospheres. Annealing under flowing AsH3/Ar was carried out without wafer encapsulation. Rapid capless annealing activated implants in GaAs with good mobility and surface morphology. Typical mobilities were 3700 4500 cm2/V-s for n-layers with about 2×1017cm-3 carrier concentration and 50 150 cm2/v-s for 0.1 5xl019 cm-3 doped p-layers. Rapid thermal annealing was performed in a vertical quartz tube where different gases (N2, AsH3/H2, AsH3/Ar) can be introduced. Samples were encapsulated with SiO when N2 was used. Tungsten-halogen lamps of 600 or 1000 W were utilized for annealing GaAs wafers ranging from 1 to 10 cm2 in area and 0.025 to 0.040 cm in thickness. The transient temperature at the wafer position was monitored using a fine thermocouple. We carried out experiments for energies of 30 to 200 keV, doses of 2×1012 to 1×1015 cm-2, and peak temperatures ranging from 600 to 1000‡C. Most results quoted are in the 700 to 870‡C temperature range. Data on implant conditions, optimum anneal conditions, electrical characteristics, carrier concentration profiles, and atomic profiles of the implanted layers are described.

  3. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Science.gov (United States)

    Liu, Xingguang; Iamvasant, Chanon; Liu, Chang; Matthews, Allan; Leyland, Adrian

    2017-01-01

    CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also found that, with sufficient Cu content (>12 at.%), annealing at a moderately high temperature (e.g. 500 °C) leads to transportation of both Cu and Ag (even at relatively low concentrations of Ag, ≤3 at.%) from inside the coating to the coating surface, which resulted in significant reductions in friction coefficient, by over 50% compared to that of the substrate (from 0.31 to 0.14 with a hemispherical diamond indenter, and from 0.83 to 0.40 with an alumina ball counterface, respectively). Results indicate that the addition of both Cu and Ag (in appropriate concentrations) to nitrogen-containing chromium is a viable strategy for the development of 'self-replenishing' silver-containing thin film architectures for temperature-dependent solid lubrication requirements or antimicrobial coating applications.

  4. Electrically-inactive phosphorus re-distribution during low temperature annealing

    Science.gov (United States)

    Peral, Ana; Youssef, Amanda; Dastgheib-Shirazi, Amir; Akey, Austin; Peters, Ian Marius; Hahn, Giso; Buonassisi, Tonio; del Cañizo, Carlos

    2018-04-01

    An increased total dose of phosphorus (P dose) in the first 40 nm of a phosphorus diffused emitter has been measured after Low Temperature Annealing (LTA) at 700 °C using the Glow Discharge Optical Emission Spectrometry technique. This evidence has been observed in three versions of the same emitter containing different amounts of initial phosphorus. A stepwise chemical etching of a diffused phosphorus emitter has been carried out to prepare the three types of samples. The total P dose in the first 40 nm increases during annealing by 1.4 × 1015 cm-2 for the sample with the highly doped emitter, by 0.8 × 1015 cm-2 in the middle-doped emitter, and by 0.5 × 1015 cm-2 in the lowest-doped emitter. The presence of surface dislocations in the first few nanometers of the phosphorus emitter might play a role as preferential sites of local phosphorus gettering in phosphorus re-distribution, because the phosphorus gettering to the first 40 nm is lower when this region is etched stepwise. This total increase in phosphorus takes place even though the calculated electrically active phosphorus concentration shows a reduction, and the measured sheet resistance shows an increase after annealing at a low temperature. The reduced electrically active P dose is around 0.6 × 1015 cm-2 for all the emitters. This can be explained with phosphorus-atoms diffusing towards the surface during annealing, occupying electrically inactive configurations. An atomic-scale visual local analysis is carried out with needle-shaped samples of tens of nm in diameter containing a region of the highly doped emitter before and after LTA using Atom Probe Tomography, showing phosphorus precipitates of 10 nm and less before annealing and an increased density of larger precipitates after annealing (25 nm and less).

  5. Influence of Different Annealing Ambients on the Properties of Zinc Sulfide Prepared by Atomic Layer Deposition

    Science.gov (United States)

    Yoo, Dongjun; Heo, Seung Chan; Choi, Moon Suk; Kim, Dohyung; Chung, Chulwon; Choi, Hag Young; Jeon, Hyeongtag; Choi, Changhwan

    2013-10-01

    The effects of different post annealing ambients (vacuum, O2, and H2S gases) on the chemical, structural, and optical properties of zinc sulfide (ZnS) thin films prepared by atomic layer deposition (ALD) were investigated. Diethylzinc [DEZ, Zn(C2H5)2] and H2S gas were used as precursor and reactant gas, respectively. Compared to as-deposited 50-nm-thick ZnS film, the optical energy band gap (Eg) of ZnS annealed under vacuum and H2S conditions increased from 3.73 to 3.85 eV, while it decreased down to 3.23 eV for the O2 annealing case. The change in the Eg of the thicker ZnS is similar to that of the thinner ZnS case. This behavior is related to the change in the Zn to S ratio. The vacuum and H2S anneals increases the Zn/S ratio, leading to higher Zn interstitial defects or S vacancy sites in the films. X-ray diffraction analysis reveals that ZnS thin film has a preferred orientation of hexagonal wurtizte (002) and cubic zinc blend (111) at ˜28.2°, and its grain size changes in a range from 18.79 to 28.14 nm after annealing. However, for O2 annealing, the patterns of both the newly formed ZnO phase and the reduced ZnS phase appear at 34.04°. This result suggests that change in the composition and crystal structure during the process significantly affects the optical properties of ZnS thin film, which should be taken into consideration in searching for an alternative buffer layer for Cu2InGaSe(S)4 (CIGS) thin film solar cell systems.

  6. Interrogating the Effects of Radiation Damage Annealing on Helium Diffusion Kinetics in Apatite

    Science.gov (United States)

    Willett, C. D.; Fox, M.; Shuster, D. L.

    2015-12-01

    Apatite (U-Th)/He thermochronology is commonly used to study landscape evolution and potential links between climate, erosion and tectonics. The technique relies on a quantitative understanding of (i) helium diffusion kinetics in apatite, (ii) an evolving 4He concentration, (iii) accumulating damage to the crystal lattice caused by radioactive decay[1], and (iv) the thermal annealing of such damage[2],[3], which are each functions of both time and temperature. Uncertainty in existing models of helium diffusion kinetics has resulted in conflicting conclusions, especially in settings involving burial heating through geologic time. The effects of alpha recoil damage annealing are currently assumed to follow the kinetics of fission track annealing (e.g., reference [3]), although this assumption is difficult to fully validate. Here, we present results of modeling exercises and a suite of experiments designed to interrogate the effects of damage annealing on He diffusivity in apatite that are independent of empirical calibrations of fission track annealing. We use the existing experimental results for Durango apatite[2] to develop and calibrate a new function that predicts the effects of annealing temperature and duration on measured diffusivity. We also present a suite of experiments conducted on apatite from Sierra Nevada, CA granite to establish whether apatites with different chemical compositions have the same behavior as Durango apatite. Crystals were heated under vacuum to temperatures between 250 and 500°C for 1, 10, or 100 hours. The samples were then irradiated with ~220 MeV protons to produce spallogenic 3He, the diffusant then used in step-heating diffusion experiments. We compare the results of these experiments and model calibrations to existing models. Citations: [1]Shuster, D., Flowers R., and Farley K., (2006), EPSL 249(3-4), 148-161; [2]Shuster, D. and Farley, K., (2009), GCA 73 (1), 6183-6196; [3]Flowers, R., Ketcham, R., Shuster, D. and Farley, K

  7. Crystalline structure changes in preoriented metallocene-based isotactic polypropylene upon annealing.

    Science.gov (United States)

    Wang, Yan; Xu, Jia-Zhuang; Chen, Yan-Hui; Qiao, Kai; Xu, Ling; Ji, Xu; Li, Zhong-Ming; Hsiao, Benjamin S

    2013-06-13

    Partially melted metallocene-based isotactic polypropylene (m-iPP), which was preoriented with a high degree of molecular orientation and a shish-kebab structure, was annealed at various temperatures and isothermally crystallized at 130 °C. The melting and crystallization process was examined using synchrotron wide-angle X-ray diffraction, small-angle X-ray scattering, and differential scanning calorimetry. For the m-iPP samples annealed at relatively low temperatures, lamellar thickening, lateral growth, and a decrease in the γ-crystal fraction occurred. Because of parallel evolution of α- and γ-crystal growth in the limited crystallizable melt volume, the fraction of γ-crystals was very low. Furthermore, topological constraints in the melt dominate the chain flux in crystal evolution; the chains are consumed by the thickening lamellae and lateral growth, forming α-crystals with parallel chains in the unit cell. For the m-iPP samples isothermally annealed at medium annealing temperatures, the increase in the amount of crystallizable melt caused the γ-crystal fraction to increase. A shish-kebab (α-crystals) structure with high thermal stability and a newly formed macro-unoriented structure coexisted in the final sample. After annealing at high temperatures, at which no crystals survived, γ-crystal formation was greatly favored; this was attributed to the nature of m-iPP molecules and their dynamic behavior at 130 °C. Because of the lack of oriented nuclei, randomly oriented lamellae were formed. On the basis of the structural cooperative changes at different scales, the morphological features at different annealing temperatures were proposed.

  8. Exploratory Study of Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A., Kryukov, A.M., Nikolaev, Y.A., Korolev, Y.N. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)], Sokolov, M.A., Nanstad, R.K. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVS) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The working group agreed that each side would irradiate, anneal, reirradiate (if feasible), and test two materials of the other; so far, only charpy impact and tensile specimens have been included. Oak Ridge National Laboratory (ornl) conducted such a program (irradiation and annealing) with two weld metals representative of VVER-440 AND VVER-1000 RPVS, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation,annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) program plate 02 and Heavy-Section Steel Irradiation (HSSI) program weld 73w. The results for each material from each laboratory are compared with those from the other laboratory. the ORNL experiments with the VVER welds included irradiation to about 1 x 10 (exp 19) N/SQ CM ({gt}1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 X 10 (exp 19) N/SQ CM ({gt}1 MeV).

  9. Phage annealing proteins promote oligonucleotide-directed mutagenesis in Escherichia coli and mouse ES cells

    Directory of Open Access Journals (Sweden)

    Muyrers Joep PP

    2003-01-01

    Full Text Available Abstract Background The phage protein pairs, RecE/RecT from Rac or Redα/Redβ from λ, initiate efficient double strand break repair (DSBR in Escherichia coli that has proven very useful for DNA engineering. These phage pairs initiate DSBR either by annealing or by another mechanism that is not defined. Results Here we report that these proteins also mediate single strand oligonucleotide repair (ssOR at high efficiencies. The ssOR activity, unlike DSBR, does not require a phage exonuclease (RecE or Redα but only requires a phage annealing protein (RecT or Redβ. Notably, the P22 phage annealing protein Erf, which does not mediate the same DSBR reactions, also delivers ssOR activity. By altering aspects of the oligonucleotides, we document length and design parameters that affect ssOR efficiency to show a simple relationship to homologies either side of the repair site. Notably, ssOR shows strand bias. Oligonucleotides that can prime lagging strand replication deliver more ssOR than their leading complements. This suggests a model in which the annealing proteins hybridize the oligonucleotides to single stranded regions near the replication fork. We also show that ssOR is a highly efficient way to engineer BACs and can be detected in a eukaryotic cell upon expression of a phage annealing protein. Conclusion Phage annealing proteins can initiate the recombination of single stranded oligonucleotides into endogenous targets in Escherichia coli at very high efficiencies. This expands the repertoire of useful DNA engineering strategies, shows promise for applications in eukaryotic cells, and has implications for the unanswered questions regarding DSBR mediated by RecE/RecT and Redα/Redβ.

  10. Thermal annealing response following irradiation of a CMOS imager for the JUICE JANUS instrument

    Science.gov (United States)

    Lofthouse-Smith, D.-D.; Soman, M. R.; Allanwood, E. A. H.; Stefanov, K. D.; Holland, A. D.; Leese, M.; Turne, P.

    2018-03-01

    ESA's JUICE (JUpiter ICy moon Explorer) spacecraft is an L-class mission destined for the Jovian system in 2030. Its primary goals are to investigate the conditions for planetary formation and the emergence of life, and how does the solar system work. The JANUS camera, an instrument on JUICE, uses a 4T back illuminated CMOS image sensor, the CIS115 designed by Teledyne e2v. JANUS imager test campaigns are studying the CIS115 following exposure to gammas, protons, electrons and heavy ions, simulating the harsh radiation environment present in the Jovian system. The degradation of 4T CMOS device performance following proton fluences is being studied, as well as the effectiveness of thermal annealing to reverse radiation damage. One key parameter for the JANUS mission is the Dark current of the CIS115, which has been shown to degrade in previous radiation campaigns. A thermal anneal of the CIS115 has been used to accelerate any annealing following the irradiation as well as to study the evolution of any performance characteristics. CIS115s have been irradiated to double the expected End of Life (EOL) levels for displacement damage radiation (2×1010 protons, 10 MeV equivalent). Following this, devices have undergone a thermal anneal cycle at 100oC for 168 hours to reveal the extent to which CIS115 recovers pre-irradiation performance. Dark current activation energy analysis following proton fluence gives information on trap species present in the device and how effective anneal is at removing these trap species. Thermal anneal shows no quantifiable change in the activation energy of the dark current following irradiation.

  11. Microstructural study of annealed gold-silicon thin films under nanoindentation

    International Nuclear Information System (INIS)

    Lee, W.-S.; Fong, F.-J.

    2008-01-01

    The mechanical properties of as-deposited Au/Si thin films indented to depths of 1000 nm are measured using a nanoindentation technique. The microstructural evolution of the as-deposited indented specimens and specimens annealed at temperatures of 250, 350 and 450 deg. C, respectively, are examined via transmission electron microscopy (TEM). The initial deposited thin film system is a composite structure consisting of a 500 nm Au thin film, a 5 nm Cr adhesive layer and a Si(1 0 0) substrate. The Au thin film has a polycrystalline structure, while both the Cr adhesive layer and the Si substrate have a single crystal state. The experimental nanoindentation results for the as-deposited specimens show that the loading curves are continuous and smooth. However, a pop-out feature is observed in the unloading curves. Furthermore, a pile-up of the thin film material is observed around the edges of the indentation. By contrast, a total recovery of the plastic zones in the indentation site takes place in the annealed specimens. TEM observations show that the microstructural evolution of the thin films within the indentation zone is strongly dependent on the annealing temperature. In the case of the as-deposited specimens, the indentation pressure induces a chain-like island structure and a distorted crystalline structure within the indentation zone. However, in the specimens annealed at temperatures of 250 and 350 deg. C, respectively, the microstructure of the indentation zone changes from a distorted crystalline structure to an amorphous phase as a result of the plastic deformation induced during indentation. The pop-out event observed in the unloading curve of the as-deposited specimens is also thought to be related to a similar amorphous transformation. At an annealing temperature of 450 deg. C, the microstructure contains both amorphous phase and crystalline eutectic phase. The formation of eutectic phase is the result of a higher annealing temperature and a greater

  12. Study on fine annealing process of the large-aperture K9 glasses

    Science.gov (United States)

    Gang, Wang; Bin, Liu Yi; Zheng, Li Li; Hui, Zhang; Lei, Xie; Min, Qiu Fu; Ping, Ma; Yao, Yan Ding

    2016-10-01

    Study on fine annealing process of the large-aperture K9 glasses was carried out in the report. The process parameters of glass placed way, fan speed and design of the cavity for keeping temperature uniformity were attained. By the fine annealing experiment, the stress distribution was improved evidently. The stress changed from Irregular distribution to consistency symmetric distribution and the stress max was reduced. The surface profile accuracy of the large-aperture K9 glasses was controlled steadily during CNC polishing.

  13. Annealing effect and photovoltaic properties of nano-ZnS/textured p-Si heterojunction.

    Science.gov (United States)

    Ji, Liang-Wen; Hsiao, Yu-Jen; Tang, I-Tseng; Meen, Teen-Hang; Liu, Chien-Hung; Tsai, Jenn-Kai; Wu, Tien-Chuan; Wu, Yue-Sian

    2013-11-09

    The preparation and characterization of heterojunction solar cell with ZnS nanocrystals synthesized by chemical bath deposition method were studied in this work. The ZnS nanocrystals were characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Lower reflectance spectra were found as the annealing temperature of ZnS film increased on the textured p-Si substrate. It was found that the power conversion efficiency (PCE) of the AZO/ZnS/textured p-Si heterojunction solar cell with an annealing temperature of 250°C was η = 3.66%.

  14. The annealing of phosphorus-implanted silicon investigated at low temperatures

    International Nuclear Information System (INIS)

    Wagner, C.; Burkhardt, F.

    1978-01-01

    Phosphorus ions are implanted at 50 keV into misaligned silicon crystals at 20 and 300 0 C, respectively. The ion doses used are 8 x 10 13 and 8 x 10 14 cm -2 , respectively. After annealing treatments the electrical properties of the samples are investigated by measuring Hall effect and sheet resistivity in the range from 300 to 4.2 K. The experimental results indicate some problems which must be taken into account for interpreting Hall effect measurements made at room temperature only. Furthermore the results give some new information on the annealing process in phosphorus implanted silicon and the influence of the implantation parameters. (author)

  15. A hybrid Genetic and Simulated Annealing Algorithm for Chordal Ring implementation in large-scale networks

    DEFF Research Database (Denmark)

    Riaz, M. Tahir; Gutierrez Lopez, Jose Manuel; Pedersen, Jens Myrup

    2011-01-01

    The paper presents a hybrid Genetic and Simulated Annealing algorithm for implementing Chordal Ring structure in optical backbone network. In recent years, topologies based on regular graph structures gained a lot of interest due to their good communication properties for physical topology...... of the networks. There have been many use of evolutionary algorithms to solve the problems which are in combinatory complexity nature, and extremely hard to solve by exact approaches. Both Genetic and Simulated annealing algorithms are similar in using controlled stochastic method to search the solution....... The paper combines the algorithms in order to analyze the impact of implementation performance....

  16. Thermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces

    Directory of Open Access Journals (Sweden)

    Valeria Bragaglia

    2017-08-01

    Full Text Available A high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111 oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.

  17. An Alternative Approach for Improving Performance of Organic Photovoltaics by Light-Enhanced Annealing

    Directory of Open Access Journals (Sweden)

    En-Ping Yao

    2014-01-01

    Full Text Available This work proposes an approach for improving the performance of poly(3-hexylthiophene (P3HT- based organic photovoltaics (OPVs. P3HT-based bulk heterojunction (BHJ film can absorb the energy from 532 nm laser light and be transformed into favorable morphology. A combination of traditional thermal annealing and laser annealing improved device performance, with a slight increase in fill factor and a significant improvement in short-circuit current density. Better crystallization and a higher degree of molecular order in the thermal/laser coannealed P3HT-based BHJ film were observed through X-ray diffraction and Raman spectroscopy.

  18. Annealing Effects on the Magnetization of Co-Ni-B Amorphous Nanoparticles

    International Nuclear Information System (INIS)

    Vargas, J.M.

    2001-01-01

    Chemically prepared (Co x Ni 1-x ) 1 00 -y B y (x=0.5, 0.75, 1; y∼30) amorphous fine particles were characterized by x-ray diffraction, DTA and TGA, and in-situ magnetic measurement as a function of annealing temperature in an inert atmosphere.Magnetic measurement performed in as prepared and ∼150C degree annealed samples show an increase of the saturation magnetization and magnetic moment after thermal tretment.Room temperature magnetization increases by factors of ∼3 in average.These measurements may indicate a local re-ordering of the amorphous phase at temperatures much lower than the full crystallization temperature

  19. Effect of annealing atmosphere on optic-electric properties of Zn O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, C. [Benemerita Universidad Autonoma de Puebla, Facultad de Ingenieria, Blvd. Valsequillo y Av. San Claudio s/n, 72570 Puebla (Mexico); Pacio, M.; Juarez, H. [Benemerita Universidad Autonoma de Puebla, Posgrado en Dispositivos Semiconductores, Av. San Claudio y 14 Sur, 72450 Puebla (Mexico); Osorio, E. [Universidad de Quinta Roo, Blvd. Bahia s/n, esquina Ignacio Comonfort, El Bosque, 77019 Chetumal, Quintana Roo (Mexico); Perez, R., E-mail: cba3009@gmail.com [Benemerita Universidad Autonoma de Puebla, Facultad de Ingenieria Quimica, Av. San Claudio y 18 Sur, 72570 Puebla (Mexico)

    2017-11-01

    In this work the study of structural, morphologic characteristics, optical and electrical properties of the thin films of Zn O in temperatures and annealing atmospheres different was realized. The films were obtained by the sol-gel method, utilizing zinc acetate dihydrate as the precursor, monoethanolamine (Mea) as a stabilizing agent and 2-methoxyethanol as a solvent and deposited by spin-coating. The films were crystallized at 600, 800 and 1000 degrees Celsius in oxygen and nitrogen atmospheres. The results obtained by XRD, Sem, photoluminescence and Hall effects of the Zn O films were related and depend strongly on the temperature and atmosphere annealing. (Author)

  20. Annealing of natural metamict zircons: II high degree of radiation damage

    CERN Document Server

    Colombo, M

    1998-01-01

    In situ time-dependent high-temperature X-ray powder diffraction was used to study the amorphous to crystalline transition in natural zircons which are characterized by a high degree of radiation damage. It was possible to distinguish two stages of the annealing process: (i) the recovery of the heavily disturbed but still crystalline domains and (ii) the recrystallization of the amorphous regions. The first stage is very fast under the chosen experimental conditions and, at least apparently, is not thermally activated. The second stage is a diffusion-controlled process, whose products (zircon or zircon and zirconia phases) are strongly correlated to the annealing temperature.

  1. Using Gaussian Process Annealing Particle Filter for 3D Human Tracking

    Directory of Open Access Journals (Sweden)

    Michael Rudzsky

    2008-01-01

    Full Text Available We present an approach for human body parts tracking in 3D with prelearned motion models using multiple cameras. Gaussian process annealing particle filter is proposed for tracking in order to reduce the dimensionality of the problem and to increase the tracker's stability and robustness. Comparing with a regular annealed particle filter-based tracker, we show that our algorithm can track better for low frame rate videos. We also show that our algorithm is capable of recovering after a temporal target loss.

  2. Effect of annealing atmosphere on optic-electric properties of Zn O thin films

    International Nuclear Information System (INIS)

    Bueno, C.; Pacio, M.; Juarez, H.; Osorio, E.; Perez, R.

    2017-01-01

    In this work the study of structural, morphologic characteristics, optical and electrical properties of the thin films of Zn O in temperatures and annealing atmospheres different was realized. The films were obtained by the sol-gel method, utilizing zinc acetate dihydrate as the precursor, monoethanolamine (Mea) as a stabilizing agent and 2-methoxyethanol as a solvent and deposited by spin-coating. The films were crystallized at 600, 800 and 1000 degrees Celsius in oxygen and nitrogen atmospheres. The results obtained by XRD, Sem, photoluminescence and Hall effects of the Zn O films were related and depend strongly on the temperature and atmosphere annealing. (Author)

  3. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  4. Kinetics of Solute Partitioning During Intercritical Annealing of a Medium-Mn Steel

    Science.gov (United States)

    Kamoutsi, H.; Gioti, E.; Haidemenopoulos, Gregory N.; Cai, Z.; Ding, H.

    2015-11-01

    The evolution of austenite fraction and solute partitioning (Mn, Al, and C) during intercritical annealing was calculated for a medium-Mn steel containing 11 pct Mn. Austenite growth takes place in three stages. The first stage is growth under non-partitioning local equilibrium (NPLE) controlled by carbon diffusion in ferrite. The second stage is growth under partitioning local equilibrium (PLE) controlled by diffusion of Mn in ferrite. The third stage is shrinkage of austenite under PLE controlled by diffusion of Mn in austenite. During PLE growth, the austenite is progressively enriched in Mn. Compositional spikes evolve early during NPLE growth and broaden with annealing temperature and time.

  5. Microstructural dynamics of Bi-2223/Ag tapes annealed in 8% O2

    DEFF Research Database (Denmark)

    Andersen, L.G.; Poulsen, H.F.; Abrahamsen, A.B.

    2002-01-01

    The microstructural dynamics of Bi-2223 tapes are investigated in situ during annealing in 8% O-2 by means of 100 keV x-ray diffraction. A green mono- and a green multi-filamentary tape are annealed at 829.5 degreesC. During ramp-up (Ca,Sr)(2)PbO4 decomposes above 750 degreesC, resulting...... degreesC on quenched tapes shows a reaction over 3 weeks, whereby randomly oriented 3222 grains are formed and Bi-2223 is depleted of Pb. Simultaneously, the critical current decreases by a factor of 2....

  6. Instantons in Quantum Annealing: Thermally Assisted Tunneling Vs Quantum Monte Carlo Simulations

    Science.gov (United States)

    Jiang, Zhang; Smelyanskiy, Vadim N.; Boixo, Sergio; Isakov, Sergei V.; Neven, Hartmut; Mazzola, Guglielmo; Troyer, Matthias

    2015-01-01

    Recent numerical result (arXiv:1512.02206) from Google suggested that the D-Wave quantum annealer may have an asymptotic speed-up than simulated annealing, however, the asymptotic advantage disappears when it is compared to quantum Monte Carlo (a classical algorithm despite its name). We show analytically that the asymptotic scaling of quantum tunneling is exactly the same as the escape rate in quantum Monte Carlo for a class of problems. Thus, the Google result might be explained in our framework. We also found that the transition state in quantum Monte Carlo corresponds to the instanton solution in quantum tunneling problems, which is observed in numerical simulations.

  7. Diffusion during growth and annealing of Co/Cu (111) films

    CERN Document Server

    Su Run; Qian Hai Jie; Kurash

    2002-01-01

    Electronic structure of MBE-grown Co/Cu (111) films was studied by synchrotron radiation angular-resolved photoemission spectra and auger electron spectra during the process of growth and annealing. The experiment reveals that: the energy shift of s-d sub z sup 2 -hybridized band of copper increases with thickening of the coverage of cobalt, which proves that atomic intermixing occurs at the interface, and there is mainly surface diffusion, not bulk interdiffusion during annealing. The authors attribute the diffusion in the two different processes to one driving force, i.e. the surface free energy of cobalt is remarkably larger than that of copper

  8. Annealing behaviour of a nanostructured Cu–45 at.%Ni alloy

    DEFF Research Database (Denmark)

    Tian, Hui; Suo, H. L.; Mishin, Oleg

    2013-01-01

    The microstructure and crystallographic texture have been investigated in a Cu–45 at.%Ni alloy after heavy rolling and subsequent annealing at different temperatures. Cold-rolling to a von Mises strain of 5.7 produced a sample with an average boundary spacing along the normal direction of ~70 nm...... microstructure promotes grain growth, which leads to a significant strengthening of the cube texture and to a dramatic loss of HABs. After 1 h of annealing at 1000 °C the fraction of the cube texture reaches 99 % and the HAB fraction is 12 %....

  9. The influence of thermal annealing on structure and oxidation of iron nanowires

    Directory of Open Access Journals (Sweden)

    Krajewski Marcin

    2015-03-01

    Full Text Available Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic field. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (Ta. At higher Ta, hematite was the dominant phase in the nanowires.

  10. Alloying and microstructural changes in platinum–titanium milled and annealed powders

    International Nuclear Information System (INIS)

    Maweja, Kasonde; Phasha, M.J.; Yamabe-Mitarai, Y.

    2012-01-01

    Graphical abstract: (a) SE-SEM micrographs of PtTi martensite formed in powder milled for short time annealed at 1500 °C and quenched in helium gas flow (b) BSE-SEM of structure formed after slow cooling. Highlights: ► A disordered metastable FCC Pt(Ti) solid solution was formed after longer milling period. ► HCP Ti crystals were first deformed and then the atoms were dissolved in strained FCC Pt lattices. ► Longer milling time suppressed the occurrence of martensitic transformation after annealing. ► Martensite phase was formed in products that went through a short milling time then annealed and quenched. ► The width of the martensite features formed was smaller at higher cooling rates. - Abstract: Equiatomic platinum–titanium powder mixtures were processed by high energy ball milling under argon atmosphere and sintered under vacuum. Evolution of the crystal structures and microstructures of the products formed were investigated by XRD and SEM techniques, respectively. The HCP crystals of Ti were first deformed and then a disordered metastable FCC Pt(Ti) solid solution was formed during milling due to semi-coherency of FCC lattices. A nanostructured Pt(Ti) product was formed after long milling time, which contained 44–47 at.% Ti and 53–56 at.% Pt. An ordered PtTi intermetallic was formed by annealing the metastable Pt(Ti) at temperature above 1300 °C. The crystal structure and microstructure of the TiPt phase depended on the milling time, annealing temperature and the cooling rate. The B19 PtTi plate martensite was formed after annealing at 1500 °C and quenching at a cooling rate of 23 °C/min to 200 °C/min for short time milled products. The width of martensite features was smaller at high cooling rate. In PtTi products milled for longer time, no martensitic transformation was observed on cooling the annealed samples. Small amounts of Pt 5 Ti 3 were formed in the powders milled for 16 h or more, followed by annealing at 1500 °C and furnace

  11. Kinetics of the electronic center annealing in Al2O3 crystals

    Science.gov (United States)

    Kuzovkov, V. N.; Kotomin, E. A.; Popov, A. I.

    2018-04-01

    The experimental annealing kinetics of the primary electronic F, F+ centers and dimer F2 centers observed in Al2O3 produced under neutron irradiation were carefully analyzed. The developed theory takes into account the interstitial ion diffusion and recombination with immobile F-type and F2-centers, as well as mutual sequential transformation with temperature of three types of experimentally observed dimer centers which differ by net charges (0, +1, +2) with respect to the host crystalline sites. The relative initial concentrations of three types of F2 electronic defects before annealing are obtained, along with energy barriers between their ground states as well as the relaxation energies.

  12. Integrated solutions for atmosphere production and control when annealing thermal exchanger tubes

    International Nuclear Information System (INIS)

    Chaffotte, Florent; Pinte, Gilles; Bockel-Macal, Savine; Bruchet, Pierre

    2012-01-01

    After having outlined and described the role of the atmosphere for tube annealing processes (carbon exchanges, gas phase interactions, carbon transfer at the metal-gas interface, carbon diffusion within tubes, parameters affecting oxidation), this article presents different solutions aimed at the production of atmospheres for tube annealing: nitrogen-diluted endothermic atmosphere, or nitrogen-hydrogen atmospheres. It discusses how this atmosphere must be selected. It presents different solutions for the control of these atmospheres: control of carbon potential, or control of the carbon flow. The benefits of such a control are illustrated by an example where tubes are processed in a continuous oven equipped with rollers heated by radiating tubes

  13. The effect of annealing on the elastoplastic and viscoelastic responses of isotactic polypropylene

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2003-01-01

    to thermal treatment and on specimens annealed at 140 C, and (iii) in a series of tensile relaxation tests on non-annealed specimens. Constitutive equations are derived for the elastoplastic and non-linear viscoelastic responses of semicrystalline polymers. A polymer is treated as an equivalent transient....... The elastoplastic behavior is modelled as sliding of junctions in meso-domains with respect to their reference positions driven by macro-deformation. The viscoelastic response is attributed to detachment of active strands from temporary junctions and attachment of dangling chains to the network. Constitutive...

  14. Annealing of natural metamict zircons: II high degree of radiation damage

    International Nuclear Information System (INIS)

    Colombo, M.; Chrosch, J.

    1998-01-01

    In situ time-dependent high-temperature X-ray powder diffraction was used to study the amorphous to crystalline transition in natural zircons which are characterized by a high degree of radiation damage. It was possible to distinguish two stages of the annealing process: (i) the recovery of the heavily disturbed but still crystalline domains and (ii) the recrystallization of the amorphous regions. The first stage is very fast under the chosen experimental conditions and, at least apparently, is not thermally activated. The second stage is a diffusion-controlled process, whose products (zircon or zircon and zirconia phases) are strongly correlated to the annealing temperature

  15. A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

    Science.gov (United States)

    Willett, Chelsea D.; Fox, Matthew; Shuster, David L.

    2017-11-01

    Widely used to study surface processes and the development of topography through geologic time, (U-Th)/He thermochronometry in apatite depends on a quantitative description of the kinetics of 4He diffusion across a range of temperatures, timescales, and geologic scenarios. Empirical observations demonstrate that He diffusivity in apatite is not solely a function of temperature, but also depends on damage to the crystal structure from radioactive decay processes. Commonly-used models accounting for the influence of thermal annealing of radiation damage on He diffusivity assume the net effects evolve in proportion to the rate of fission track annealing, although the majority of radiation damage results from α-recoil. While existing models adequately quantify the net effects of damage annealing in many geologic scenarios, experimental work suggests different annealing rates for the two damage types. Here, we introduce an alpha-damage annealing model (ADAM) that is independent of fission track annealing kinetics, and directly quantifies the influence of thermal annealing on He diffusivity in apatite. We present an empirical fit to diffusion kinetics data and incorporate this fit into a model that tracks the competing effects of radiation damage accumulation and annealing on He diffusivity in apatite through geologic time. Using time-temperature paths to illustrate differences between models, we highlight the influence of damage annealing on data interpretation. In certain, but not all, geologic scenarios, the interpretation of low-temperature thermochronometric data can be strongly influenced by which model of radiation damage annealing is assumed. In particular, geologic scenarios involving 1-2 km of sedimentary burial are especially sensitive to the assumed rate of annealing and its influence on He diffusivity. In cases such as basement rocks in Grand Canyon and the Canadian Shield, (U-Th)/He ages predicted from the ADAM can differ by hundreds of Ma from those

  16. Annealing temperature effect on structure and electrical properties of films formed of Ge nanoparticles in SiO2

    International Nuclear Information System (INIS)

    Stavarache, Ionel; Lepadatu, Ana-Maria; Stoica, Toma; Ciurea, Magdalena Lidia

    2013-01-01

    Ge–SiO 2 films with high Ge/Si atomic ratio of about 1.86 were obtained by co-sputtering of Ge and SiO 2 targets and subsequently annealed at different temperatures between 600 and 1000 °C in a conventional furnace in order to show how the annealing process influences the film morphology concerning the Ge nanocrystal and/or amorphous nanoparticle formation and to study their electrical behaviour. Atomic force microscopy (AFM) imaging, Raman spectroscopy and electrical conductance measurements were performed in order to find out the annealing effect on the film surface morphology, as well as the Ge nanoparticle formation in correlation with the hopping conductivity of the films. AFM images show that the films annealed at 600 and 700 °C present a granular surface with particle height of about 15 nm, while those annealed at higher temperatures have smoother surface. The Raman investigations evidence Ge nanocrystals (including small ones) coexisting with amorphous Ge in the films annealed at 600 °C and show that almost all Ge is crystallized in the films annealed at 700 °C. The annealing at 800 °C disadvantages the Ge nanocrystal formation due to the strong Ge diffusion. This transition in Ge nanocrystals formation process by annealing temperature increase from 700 to 800 °C revealed by AFM and Raman spectroscopy measurements corresponds to a change in the electrical transport mechanism. Thus, in the 700 °C annealed films, the current depends on temperature according to a T −1/2 law which is typical for a tunnelling mechanism between neighbour Ge nanocrystals. In the 800 °C annealed films, the current–temperature characteristic has a T −1/4 dependence showing a hopping mechanism within an electronic band of localized states related to diffused Ge in SiO 2 .

  17. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingguang, E-mail: xingguangliu1@gmail.com [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Iamvasant, Chanon, E-mail: ciamvasant1@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Liu, Chang, E-mail: chang.liu@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Matthews, Allan, E-mail: allan.matthews@manchester.ac.uk [Pariser Building - B24 ICAM, School of Materials, The University of Manchester, Manchester, M13 9PL (United Kingdom); Leyland, Adrian, E-mail: a.leyland@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

    2017-01-15

    Highlights: • Coatings with nitrogen content up to 16 at.% exhibit a metallic Cr solid solution, even after post-coat annealing at 300 °C and 500 °C. • At higher N/Cr atomic ratios (approaching Cr{sub 2}N stoichiometry), chromium was still inclined to exist in solid solution with nitrogen, rather than as a ceramic nitride phase, even after annealing at 500 °C. • Transportation of Cu and Ag to the surface depends on annealing temperature, annealing duration, nitrogen concentration and ‘global’ Cu + Ag concentration. • Incorporation of copper appears to be a powerful strategy to enhance Ag mobility at low concentration (∼3 at.% Ag in this study) under moderately high service temperature. • A significant decrease in friction coefficient was obtained at room temperature after annealing, or during sliding wear testing at elevated temperature. - Abstract: CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also

  18. Microstructural analysis of the thermal annealing of ice-Ih using EBSD

    Science.gov (United States)

    Hidas, Károly; Tommasi, Andréa; Mainprice, David; Chauve, Thomas; Barou, Fabrice; Montagnat, Maurine

    2017-04-01

    Rocks deformed in the middle crust and deeper in the Earth typically remain at high temperature for extended time spans after the cessation of deformation. This results in annealing of the deformation microstructure by a series of thermally activated, diffusion-based processes, namely: recovery and static recrystallization, which may also modify the crystal preferred orientation (CPO) or texture. Understanding the effects of annealing on the microstructure and CPO is therefore of utmost importance for the interpretation of the microstructures and for the estimation of the anisotropy of physical properties of lower crustal and mantle rocks. Ice-Ih -the typical form of water ice on the Earth's surface, with hexagonal crystal symmetry- deforms essentially by glide of dislocations on the basal plane [1], thus it has high viscoplastic anisotropy, which induces strong heterogeneity of stresses and strains at both the intra- and intergranular scales [2-3]. This behavior makes ice-Ih an excellent analog material for silicate minerals that compose the Earth. In situ observations of the evolution of the microstructures and CPO during annealing enable the study of the interplay between the various physical processes involved in annealing (recovery, nucleation, grain growth). They also allow the analysis of the impact of the preexisting deformation microstructures on the microstructural and CPO evolution during annealing. Here we studied the evolution of the microstructure of ice-Ih during static recrystallization by stepwise annealing experiments. We alternated thermal annealing and electron backscatter diffraction (EBSD) analyses on polycrystalline columnar ice-Ih pre-deformed in uniaxial compression at temperature of -7 °C to strains of 3.0-5.2. Annealing experiments were carried out at -5 °C and -2 °C up to a maximum of 3.25 days, typically in 5-6 steps. EBSD crystal orientation maps obtained after each annealing step permit the description of microstructural changes

  19. Origin of two maxima in specific heat in enthalpy relaxation under thermal history composed of cooling, annealing, and heating.

    Science.gov (United States)

    Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

    2016-12-01

    The origin of two maxima in specific heat observed at the higher and the lower temperatures in the glass-transition region in the heating process has been studied for polymethyl methacrylate and polyvinyl chloride using differential scanning calorimetry, and the calculation was done using the phenomenological model equation under a thermal history of the typical annealing experiment composed of cooling, annealing, and heating. The higher maximum is observed above the glass-transition temperature, and it remains almost unchanged independent of annealing time t_{a}, while the lower one is observed above an annealing temperature T_{a} and shifts toward the higher one, increasing its magnitude with t_{a}. The analysis by the phenomenological model equation proposed in order to interpret the memory effect in the glassy state clarifies that under a typical annealing history, two maxima in specific heat essentially appear. The shift of the lower maximum toward higher temperatures from above T_{a} is caused by an increase in the amount of relaxation during annealing with t_{a}. The annealing temperature and the amount of relaxation during annealing play a major role in the determination of the number of maxima in the specific heat.

  20. Laser annealing of sputter-deposited a-SiC and a-SiCxNy films

    Indian Academy of Sciences (India)

    Administrator

    To overcome this problem, thermal or laser anneal- ing is performed to induce crystallization of the films. (Fernandez-Ramos et al 2003). In recent years, Garcia and co-workers (2004) com- pared surface roughness, resistivity and X-ray diffraction pattern observed in a-Si and a-SiC films crystallized by laser annealing under ...