Emerging therapies for Clostridium difficile infection – focus on fidaxomicin
Directory of Open Access Journals (Sweden)
Chaparro-Rojas F
2013-06-01
Full Text Available Fredy Chaparro-Rojas, Kathleen M MullaneDepartment of Medicine, Section of Infectious Diseases, University of Chicago, Chicago, IL, USAAbstract: The epidemiology of Clostridium difficile infections (CDI has evolved during the last decades, with an increase in the reported incidence, severity of cases, and rate of mortality and relapses. These increases have primarily affected some special populations including the elderly, patients requiring concomitant antibiotic therapy, patients with renal failure, and patients with cancer. Until recently, the treatment of CDI was limited to either metronidazole or vancomycin. New therapeutic options have emerged to address the shortcomings of current antibiotic therapy. Fidaxomicin stands out as the first-in-class oral macrocyclic antibiotic with targeted activity against C. difficile and minimal collateral damage on the normal colonic flora. Fidaxomicin has demonstrated performance not inferior to what is considered the “gold standard” available therapy for CDI, vancomycin, in two separate Phase III clinical trials, but with significant advantages, including fewer recurrences and higher rates of sustained clinical cures. Fidaxomicin constitutes an important development in targeted antibiotic therapy for CDI and must be considered as a first-line agent for patients with risk factors known to portend relapse and severe infection.Keywords: fidaxomicin, Clostridium difficile-associated diarrhea, CDAD, Clostridium difficile infection (CDI, vancomycin, metronidazole
Credito, Kim L; Appelbaum, Peter C
2004-11-01
Agar dilution MIC was used to compare activities of OPT-80, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, amoxicillin/clavulanate, imipenem, clindamycin, and metronidazole against 350 gram-positive and -negative anaerobes. OPT-80 was active against gram-positive strains only, especially Clostridium spp. (85 strains tested, including 21 strains of C. difficile), with MICs ranging between
Recurrent Clostridium difficile colitis in elderly: the role of fidaxomicin
Directory of Open Access Journals (Sweden)
Francesco Artom
2014-12-01
Full Text Available Clostridium difficile colitis is a substantial cause of in-hospital morbidity. Since the mortality attributable may be as high as 10%, a prompt and effective treatment is advisable. Fidaxomicin is a well-documented effective drug for the treatment of C. difficile colitis and it is particularly effective in the treatment of recurrences. We report a case of a 92-year-old woman with prolonged hospitalization and recurrent episodes (three in a three-month period of C. difficile diarrhea. Each episode initially responded to vancomycin. However, after the third episode fidaxomicin was given, with a sustained response (5 months without further episodes. In this patient fidaxomicin was safe and effective in treating recurrence of C. difficile colitis. The use of fidaxomicin as a therapy of first episode of C. difficile colitis should be considered for those patients with a predictable high risk of recurrent C. difficile colitis.http://dx.doi.org/10.7175/cmi.v8i1s.954
Biswas, J S; Patel, A; Otter, J A; Wade, P; Newsholme, W; van Kleef, E; Goldenberg, S D
2015-07-01
Fidaxomicin is sporicidal and may be associated with a reduced time to resolution of diarrhoea when used to treat patients with Clostridium difficile infection (CDI). This study investigated whether fidaxomicin for treatment of all patients with CDI reduced C. difficile environmental contamination. Surfaces in the rooms of 66 hospitalized patients treated with metronidazole and/or vancomycin and 68 hospitalized patients treated with fidaxomicin were sampled. Patients treated with fidaxomicin were less likely to contaminate their environment (25/68, 36.8%) than patients treated with metronidazole and/or vancomycin (38/66 57.6%) (P = 0.02). Treatment with fidaxomicin was associated with reduced environmental contamination with C. difficile.
Fidaxomicin versus Vancomycin in the Treatment of Clostridium difficile Infection: Canadian Outcomes
Directory of Open Access Journals (Sweden)
Christine Lee
2016-01-01
Full Text Available Background. This analysis examined the efficacy of fidaxomicin versus vancomycin in 406 Canadian patients with Clostridium difficile infection (CDI, based on data from 2 randomized, clinical trials. Methods. Patients received fidaxomicin or vancomycin 1. Patients were assessed for clinical response recurrence of infection and sustained clinical response for 28 days after treatment completion. Patients at increased risk of recurrence were subjected to subgroup analyses. Results. Clinical response rates for fidaxomicin (90.0% were noninferior to those with vancomycin (92.2%; 95% confidence interval for difference: −7.7, 3.5. However, fidaxomicin-treated patients had lower recurrence (14.4% versus 28.0%, p=0.001 and higher sustained clinical response (77.1% versus 66.3%, p=0.016. Compared with vancomycin, fidaxomicin was associated with lower recurrence rates in all subgroups, reaching statistical significance in patients with age ≥ 65 years (16.0% versus 30.9%, p=0.026, concomitant antibiotic use (16.2% versus 38.7%, p=0.036, and non-BI strains (11.8% versus 28.3%, p=0.004. Higher sustained clinical response rates were observed for fidaxomicin compared with vancomycin in all subgroups; this was statistically significant in the non-BI subgroup (82.8% versus 69.1%, p=0.021. Conclusions. In Canadian patients, fidaxomicin was superior to vancomycin in sustaining clinical response and reducing CDI recurrence.
Directory of Open Access Journals (Sweden)
Antonio Riccardo Buonuomo
2015-03-01
Full Text Available Clostridium difficile infection is a disease with increasing incidence, particularly in high‑riskpatients such as the elderly, immunocompromised patients, etc.We report an unexpected decrease of International Normalized Ratio (INR response to warfarin during a first recurrence of Clostridium difficile infection (CDI treated with fidaxomicin. The patient, an old man who has prosthetic heart valves on anticoagulation therapy with warfarin, was treated with an association of vancomycin plus metronidazole for a first episode of CDI. Patient remained symptom‑free for few days and then he presented with recurrent diarrhea. A retreatment with vancomycin and metronidazole didn’t resolve symptoms of CDI, therefore he underwent fidaxomicin treatment for 10 days, with rapid resolution of diarrhea. In the meantime, warfarin effects diminished, and only with increases of dosage INR therapeutic range was achieved few days after discontinuing fidaxomicin. According to product information, fidaxomicin doesn’t interfere with warfarin. The authors highlight the different plausible mechanisms to explain the association between the unexpected decreased effect of warfarin and factors that could have influenced such event. The frequent update of product information through good pharmacovigilance practices could help clinicians in the management of unexpected events.http://dx.doi.org/10.7175/cmi.v9i1.953
Tousseeva, Anna; Jackson, J Derek; Redell, Mark; Henry, Teresa; Hui, Michael; Capurso, Shelley; DeRyke, C Andrew
2014-12-01
Fidaxomicin is approved for the treatment of adults with Clostridium difficile-associated diarrhea, many of whom have difficulty swallowing an intact tablet. The study objective was to evaluate the stability and recovery of crushed DIFICID(®) (fidaxomicin) 200-mg tablets dispersed in water, applesauce, or Ensure(®) brand liquid nutritional supplement, and to determine the recovery of fidaxomicin from the administration of an aqueous dispersion of a crushed DIFICID(®) tablet through a nasogastric (NG) tube. DIFICID(®) tablets were crushed and dispersed in water, applesauce, or Ensure(®). The stability and recovery of fidaxomicin were evaluated over 24 h in these vehicles. In a separate experiment, the ability to recover a full dose of fidaxomicin when administering as an aqueous dispersion through an NG tube was assessed. When DIFICID(®) tablets were crushed and dispersed in water, the active ingredient, fidaxomicin, was stable for up to 2 h at room temperature. Additionally, it was stable for up to 24 h in dispersions with applesauce or Ensure(®). Recovery of fidaxomicin after crushing and dispersing in any of the three vehicles studied ranged from 95 to 108 %, which is within the normal range of individual tablet variability. When crushed, dispersed in water, and administered through an NG tube, the average recovery of fidaxomicin was 96 %. Stability and recovery of fidaxomicin were confirmed when DIFICID(®) tablets were crushed and dispersed in water, applesauce, or Ensure(®). In addition, administration of an aqueous dispersion of a crushed tablet through an NG tube is supported by acceptable recovery of fidaxomicin.
Fidaxomicin in the treatment of colitis due to Clostridium difficile: preliminary results
Directory of Open Access Journals (Sweden)
Francesco Cortese
2014-12-01
Full Text Available The incidence of Clostridium difficile infections (CDI and Clostridium difficile-Associated Diarrhea (CDAD is increasing in Canada, USA, and Europe and represents a considerable clinical problem. Both naïve and hypervirulent strains can be considered as opportunistic bacteria affecting immunocompromised, antibiotic-treated, critical, or subcritical patients with a microbiota disruption. CDI arising is strictly related to antibiotic, single or combined, and/or proton pump inhibitor treatment. CDI can cause a syndrome with systemic involvement and complex treatment, sometimes requiring surgical interventions (e.g. colectomy in fulminant colitis. Antibiotic treatment with metronidazole by mouth is the first choice and generally vancomycin is administered in case of lack of effectiveness. Fidaxomicin is a new macrocyclic antibiotic for C. difficile with microflora-sparing properties. This paper reports our initial experience in 11 patients with non-responder or relapsing CDIs. Fidaxomicin was effective in 10 cases (91%. Only one patient with an active ulcerative colitis did not respond and was treated with fecal-microbiota transplantation. In two patients diarrhea persisted, but just the ulcerative colitis one was C. difficile-related. No adverse events were experienced.http://dx.doi.org/10.7175/cmi.v8i1s.956
抗感染新药非达霉素的药理作用与临床评价%Pharmacology and clinical evaluation of the new anti-infective drug fidaxomicin
Institute of Scientific and Technical Information of China (English)
姜春梅; 刘洋; 王京晶; 张清; 康博欣
2011-01-01
Fidaxomicin (edarbi) is the antibiotic with a novel structure of macrolides for the treatment of clostridium difficile-associated diarrhea ( CDAD). Literature was searched from FDA database with the key word edarbi. The pharmacology, pharmacokinetics, clinical evaluation, safety evaluation and drug interactions of fidaxomicin were reviewed.%非达霉素( fidaxomicin)是一种新型的大环内酯类抗生素,适用于艰难梭菌相关性腹泻(clostridium difficile-associated diarrhea,CDAD)的治疗.本文参考美国FDA的相关资料,对非达霉素的药理作用、药动学、临床评价、安全性评价及药物相互作用等进行综述.
Cieniawski, Dominik; Ignacak, Ewa; Bętkowska-Prokop, Alina; Dudzik, Barbara; Walatek, Bogusław; Kuźniewski, Marek; Sułowicz, Władysław
2014-01-01
Clostridium difficile infection (CDI) is an increasingly problem in everyday clinical practice. The most important risk factor of this infection is antibiotics use. The incidence of Clostridium difficile associated diarrhea (CDAD) in patients after renal transplantation is estimated to be about 6% in the early postoperative period. Due to the applied immunosuppression and frequent infections requiring intensive, broad spectral antibiotics, the later prevalence of CDAD may remain at a similar level. Massive diarrhea caused by Clostridium difficile may lead to fluctuations in immunosuppressive drugs concentration, in renal transplant patients. The authors present a case study of a 23-year old patient after kidney transplantation from deceased donor, with diagnosed polymorphic PTLD (Post-Transplant Lymphoproliferative Disorder). During biological treatment with rituximab in this patient 4 recurrences of CDI were observed. In this article the clinical manifestation of recurrent CDAD are presented. The authors discuss therapeutic procedure with fidaxomicin use, its results and influence on immunosuppressive drugs concentration.
Gitterman, Moshe
2014-09-01
In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...
Riddle, Bob
2010-01-01
When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…
Solé, Ricard V
2011-01-01
Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o
Directory of Open Access Journals (Sweden)
J.L. Flanagan
2013-08-01
Full Text Available A vocoder technique is described in which speech signals are represented by their short-time phase and amplitude spectra. A complete transmission system utilizing this approach is simulated on a digital computer. The encoding method leads to an economy in transmission bandwidth and to a means for time compression and expansion of speech signals.
Mixed phases during the phase transitions
Tatsumi, Toshitaka; Maruyama, Toshiki
2011-01-01
Quest for a new form of matter inside compact stars compels us to examine the thermodynamical properties of the phase transitions. We closely consider the first-order phase transitions and the phase equilibrium on the basis of the Gibbs conditions, taking the liquid-gas phase transition in asymmetric nuclear matter as an example. Characteristic features of the mixed phase are figured out by solving the coupled equations for mean-fields and densities of constituent particles self-consistently within the Thomas-Fermi approximation. The mixed phase is inhomogeneous matter composed of two phases in equilibrium; it takes a crystalline structure with a unit of various geometrical shapes, inside of which one phase with a characteristic shape, called "pasta", is embedded in another phase by some volume fraction. This framework enables us to properly take into account the Coulomb interaction and the interface energy, and thereby sometimes we see the mechanical instability of the geometric structures of the mixed phase...
Phase contrast image synthesis
DEFF Research Database (Denmark)
Glückstad, J.
1996-01-01
A new method is presented for synthesizing arbitrary intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range [0; 2 pi] phase modulation. By controlling the average value of the input phase...... function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis....
Brignole, Esteban Alberto
2013-01-01
Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and
Ho, Keang-Po
2003-01-01
The characteristic function of soliton phase jitter is found analytically when the soliton is perturbed by amplifier noise. In additional to that from amplitude jitter, the nonlinear phase noise due to frequency and timing jitter is also analyzed. Because the nonlinear phase noise is not Gaussian distributed, the overall phase jitter is also non-Gaussian. For a fixed mean nonlinear phase shift, the contribution of nonlinear phase noise from frequency and timing jitter decreases with distance ...
CrowdPhase: crowdsourcing the phase problem.
Jorda, Julien; Sawaya, Michael R; Yeates, Todd O
2014-06-01
The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as `crowdsourcing'. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of `individuals', each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it possible to extract meaningful information in cases where limited resolution might otherwise prevent initial phasing.
Propagating phase interface with intermediate interfacial phase: Phase field approach
Momeni, Kasra; Levitas, Valery I.
2014-05-01
An advanced three-phase phase field approach (PFA) is suggested for a nonequilibrium phase interface that contains an intermediate phase, in particular, a solid-solid interface with a nanometer-sized intermediate melt (IM). A thermodynamic potential in the polar order parameters is developed that satisfies all thermodynamic equilibrium and stability conditions. The special form of the gradient energy allowed us to include the interaction of two solid-melt interfaces via an intermediate melt and obtain a well-posed problem and mesh-independent solutions. It is proved that for stationary 1D solutions to two Ginzburg-Landau equations for three phases, the local energy at each point is equal to the gradient energy. Simulations are performed for β ↔δ phase transformations (PTs) via IM in an HMX energetic material. The obtained energy IM width dependence is described by generalized force-balance models for short- and long-range interaction forces between interfaces but not far from the melting temperature. A force-balance model is developed that describes phase field results even 100 K below the melting temperature. The effects of the ratios of width and energies of solid-solid and solid-melt interfaces, temperature, and the parameter characterizing interaction of two solid-melt interfaces, on the structure, width, energy of the IM and interface velocity are determined by finite element method. Depending on parameters, the IM may appear by continuous or discontinuous barrierless disordering or via critical nucleus due to thermal fluctuations. The IM may appear during heating and persist during cooling at temperatures well below than it follows from sharp-interface approach. On the other hand, for some parameters when IM is expected, it does not form, producing an IM-free gap. The developed PFA represents a quite general three-phase model and can be extended to other physical phenomena, such as martensitic PTs, surface-induced premelting and PTs, premelting
High temperature phase equilibria and phase diagrams
Kuo, Chu-Kun; Yan, Dong-Sheng
2013-01-01
High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature
Engineering holographic phase diagrams
Chen, Jiunn-Wei; Dai, Shou-Huang; Maity, Debaprasad; Zhang, Yun-Long
2016-10-01
By introducing interacting scalar fields, we tried to engineer physically motivated holographic phase diagrams which may be interesting in the context of various known condensed matter systems. We introduce an additional scalar field in the bulk which provides a tunable parameter in the boundary theory. By exploiting the way the tuning parameter changes the effective masses of the bulk interacting scalar fields, desired phase diagrams can be engineered for the boundary order parameters dual to those scalar fields. We give a few examples of generating phase diagrams with phase boundaries which are strikingly similar to the known quantum phases at low temperature such as the superconducting phases. However, the important difference is that all the phases we have discussed are characterized by neutral order parameters. At the end, we discuss if there exists any emerging scaling symmetry associated with a quantum critical point hidden under the dome in this phase diagram.
Therapy Provider Phase Information
U.S. Department of Health & Human Services — The Therapy Provider Phase Information dataset is a tool for providers to search by their National Provider Identifier (NPI) number to determine their phase for...
Digital quadrature phase detection
Smith, J.A.; Johnson, J.A.
1992-05-26
A system for detecting the phase of a frequency or phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2[pi] when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2[pi] when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention. 6 figs.
Interacting Weyl fermions: Phases, phase transitions, and global phase diagram
Roy, Bitan; Goswami, Pallab; Juričić, Vladimir
2017-05-01
We study the effects of short-range interactions on a generalized three-dimensional Weyl semimetal, where the band touching points act as the (anti)monopoles of Abelian Berry curvature of strength n . We show that any local interaction has a negative scaling dimension -2 /n . Consequently, all Weyl semimetals are stable against weak short-range interactions. For sufficiently strong interactions, we demonstrate that the Weyl semimetal either undergoes a first-order transition into a band insulator or a continuous transition into a symmetry breaking phase. A translational symmetry breaking axion insulator and a rotational symmetry breaking semimetal are two prominent candidates for the broken symmetry phase. At the one-loop order, the correlation length exponent for continuous transitions is ν =n /2 , indicating their non-Gaussian nature for any n >1 . We also discuss the scaling of the thermodynamic and transport quantities in general Weyl semimetals as well as inside broken symmetry phases.
Bowers, Michael T
1979-01-01
Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation
Phase jitter in a differential phase experiment.
Tanenbaum, B. S.; Connolly, D. J.; Austin, G. L.
1973-01-01
Austin (1971) had concluded that, because of the 'phase jitter,' the differential phase experiment is useful over a more limited height range than the differential absorption experiment. Several observations are presented to show that this conclusion is premature. It is pointed out that the logical basis of the differential absorption experiment also requires that the O- and X-mode echoes, at a given time, come from the same irregularities. Austin's calculations are believed to contain a systematic error above 80 km.
Metastable phases and "metastable" phase diagrams
Brazhkin, V. V.
2006-01-01
The work discusses specifics of phase transitions for metastable states of substances. The objects of condensed media physics are primarily equilibrium states of substances with metastable phases viewed as an exception, while the overwhelming majority of organic substances investigated in chemistry are metastable. It turns out that at normal pressure many of simple molecular compounds based on light elements (these include: most hydrocarbons; nitrogen oxides, hydrates, and carbides; carbon ox...
Perceptions about Moon Phases.
Rider, Steven
2002-01-01
Presents research on different techniques to determine the level of understanding among middle school students regarding the phases of the moon. Quotes student responses to provide some insight into students' level of understanding of general knowledge about the moon, moon phases, and modeling the phases. Presents implications for teachers. (KHR)
Differential Phase Detector for Precise Phase Alignment
Olexa, Jakub
2016-01-01
This paper presents a differential phase detector circuit, whose phase-to-voltage characteristic has an extremum when its two input signals are exactly in phase. In this condition all its digital signals are of 50 % duty cycle so that the circuit characteristic does not have a dead zone. This feature allows a precise indication of the zero-phase condition, which is independent of the detector power supply and the offset of its ADC readout. Such a detector is used for a phase alignment of two reference clock signals with frequency about 11 kHz in front-ends processing signals from beam position monitors of the Large Hadron Collider (LHC) at CERN. The detector output voltage is digitized with a 24-bit ADC at the rate of the reference signals. The resulting samples are processed in the front-end FPGA and transmitted to the control system using an Ethernet data stream. After a detailed description of the differential phase detector its performance is demonstrated with laboratory measurements. The results show tha...
Shapere, Alfred D
1989-01-01
During the last few years, considerable interest has been focused on the phase that waves accumulate when the equations governing the waves vary slowly. The recent flurry of activity was set off by a paper by Michael Berry, where it was found that the adiabatic evolution of energy eigenfunctions in quantum mechanics contains a phase of geometric origin (now known as 'Berry's phase') in addition to the usual dynamical phase derived from Schrödinger's equation. This observation, though basically elementary, seems to be quite profound. Phases with similar mathematical origins have been identified
Robbins, J M
2010-01-01
Quantum eigenstates undergoing cyclic changes acquire a phase factor of geometric origin. This phase, known as the Berry phase, or the geometric phase, has found applications in a wide range of disciplines throughout physics, including atomic and molecular physics, condensed matter physics, optics, and classical dynamics. In this article, the basic theory of the geometric phase is presented along with a number of representative applications. The article begins with an account of the geometric phase for cyclic adiabatic evolutions. An elementary derivation is given along with a worked example for two-state systems. The implications of time-reversal are explained, as is the fundamental connection between the geometric phase and energy level degeneracies. We also discuss methods of experimental observation. A brief account is given of geometric magnetism; this is a Lorenz-like force of geometric origin which appears in the dynamics of slow systems coupled to fast ones. A number of theoretical developments of the...
DEFF Research Database (Denmark)
Glückstad, Jesper; Palima, Darwin
Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast...... (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than...... efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, and can even enable a Reverse Phase Contrast mode where intensity patterns are converted into a phase modulation....
Glückstad, Jesper
2009-01-01
Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, ...
DEFF Research Database (Denmark)
Glückstad, Jesper; Palima, Darwin
Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast...... (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than...... the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light...
Interacting Weyl fermions: Phases, phase transitions and global phase diagram
Roy, Bitan; Juricic, Vladimir
2016-01-01
We study the effects of short-range interactions on a generalized three-dimensional Weyl semimetal, where the band touching points act as the (anti)monopoles of Abelian Berry curvature of strength $n$. We show that any local interaction has a \\emph{negative} scaling dimension $-2/n$. Consequently all Weyl semimetals are stable against weak short-range interactions. For sufficiently strong interactions, we demonstrate that the Weyl semimetal either undergoes a first order transition into a band insulator or a continuous transition into a symmetry breaking phase. A translational symmetry breaking axion insulator and a rotational symmetry breaking semimetal are two prominent candidates for the broken symmetry phase. At one loop level, the correlation length exponent for continuous transitions is $\
Energy Technology Data Exchange (ETDEWEB)
Chao, Alexander Wu; /SLAC
2012-03-01
As accelerator technology advances, the requirements on accelerator beam quality become increasingly demanding. Facing these new demands, the topic of phase space gymnastics is becoming a new focus of accelerator physics R&D. In a phase space gymnastics, the beam's phase space distribution is manipulated and precision tailored to meet the required beam qualities. On the other hand, all realization of such gymnastics will have to obey accelerator physics principles as well as technological limitations. Recent examples of phase space gymnastics include Emittance exchanges, Phase space exchanges, Emittance partitioning, Seeded FELs and Microbunched beams. The emittance related topics of this list are reviewed in this report. The accelerator physics basis, the optics design principles that provide these phase space manipulations, and the possible applications of these gymnastics, are discussed. This fascinating new field promises to be a powerful tool of the future.
DEFF Research Database (Denmark)
Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez
2017-01-01
Single-phase phase-locked loops (PLLs) are popular for the synchronization and control of single-phase gridconnected converters. They are also widely used for monitoring and diagnostic purposes in the power and energy areas. In recent years, a large number of single-phase PLLs with different...... structures and properties have been proposed in the literature. The main aim of this paper is to provide a review of these PLLs. To this end, the single-phase PLLs are first classified into two major categories: 1) power-based PLLs (pPLLs), and 2) quadrature signal generation-based PLLs (QSG-PLLs......). The members of each category are then described and their pros and cons are discussed. This work provides a deep insight into characteristics of different single-phase PLLs and, therefore, can be considered as a reference for researchers and engineers....
Phase Equilibria Diagrams Database
SRD 31 NIST/ACerS Phase Equilibria Diagrams Database (PC database for purchase) The Phase Equilibria Diagrams Database contains commentaries and more than 21,000 diagrams for non-organic systems, including those published in all 21 hard-copy volumes produced as part of the ACerS-NIST Phase Equilibria Diagrams Program (formerly titled Phase Diagrams for Ceramists): Volumes I through XIV (blue books); Annuals 91, 92, 93; High Tc Superconductors I & II; Zirconium & Zirconia Systems; and Electronic Ceramics I. Materials covered include oxides as well as non-oxide systems such as chalcogenides and pnictides, phosphates, salt systems, and mixed systems of these classes.
Green, David G; Abbass, Hussein A
2014-01-01
This book explains how dual phase evolution operates in all these settings and provides a detailed treatment of the subject. The authors discuss the theoretical foundations for the theory, how it relates to other phase transition phenomena and its advantages in evolutionary computation and complex adaptive systems. The book provides methods and techniques to use this concept for problem solving. Dual phase evolution concerns systems that evolve via repeated phase shifts in the connectivity of their elements. It occurs in vast range of settings, including natural systems (species evolution, landscape ecology, geomorphology), socio-economic systems (social networks) and in artificial systems (annealing, evolutionary computing).
Soustelle, Michel
2015-01-01
This book is part of a set of books which offers advanced students successive characterization tool phases, the study of all types of phase (liquid, gas and solid, pure or multi-component), process engineering, chemical and electrochemical equilibria, and the properties of surfaces and phases of small sizes. Macroscopic and microscopic models are in turn covered with a constant correlation between the two scales. Particular attention has been given to the rigor of mathematical developments. This second volume in the set is devoted to the study of liquid phases.
Solid phase transformations II
Čermák, J
2009-01-01
This topical volume includes ten invited papers that cover selected areas of the field of solid phase transformations. The first two contributions represent a burgeoning branch; that of the computer simulation of physical phenomena. The following three articles deal with the thermodynamics of phase transformations as a basic theory for describing the phenomenology of phase changes in matter. The next paper describes the interconnections between structural stability and the electronic structure of phases. Two further articles are devoted to displacive transformations; a field where there are ma
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-08-01
The Utility PhotoVoltaic Group (UPVG), supported by member dues and a grant from the US Department of Energy, has as its mission the acceleration of the use of cost-effective small-scale and emerging large-scale applications of photovoltaics for the benefit of electric utilities and their customers. Formed in October, 1992, with the support of the American Public Power Association, Edison Electric Institute, and the National Rural Electric Cooperative Association, the UPVG currently has 90 members from all sectors of the electric utility industry. The UPVG`s efforts as conceived were divided into four phases: Phase 0--program plan; Phase 1--organization and strategy development; Phase 2--creating market assurance; and Phase 3--higher volume purchases. The Phase 0 effort developed the program plan and was completed early in 1993. The Phase 1 goal was to develop the necessary background information and analysis to lead to a decision as to which strategies could be undertaken by utilities to promote greater understanding of PV markets and achieve increased volumes of PV purchases. This report provides the details of the UPVG`s Phase 2 efforts to initiate TEAM-UP, its multiyear, 50-MW hardware initiative.
LIGHT NONAQUEOUS PHASE LIQUIDS
Nonaqueous phase liquids (NAPLS) are hydrocarbons that exist as a separate, immiscible phase when in contact with water and/or air. ifferences in the physical and chemical properties of water and NAPL result in the formation of a physical interface between the liquids which preve...
Shawl, Stephen J.
2010-01-01
This paper describes a lunar phases planisphere with which a user can answer questions about the rising and setting times of the Moon as well as questions about where the Moon will be at a given phase and time. The article contains figures that can be photocopied to make the planisphere. (Contains 2 figures.)
Quantum Enhanced Phase Retrieval
Liberman, Liat; Poem, Eilon; Silberberg, Yaron
2015-01-01
The retrieval of phases from intensity measurements is a key process in many fields in science, from optical microscopy to x-ray crystallography. Here we study phase retrieval of a one-dimensional multi-phase object that is illuminated by quantum states of light. We generalize the iterative Gerchberg-Saxton algorithm to photon correlation measurements on the output plane, rather than the standard intensity measurements. We report a numerical comparison of classical and quantum phase retrieval of a small one-dimensional object of discrete phases from its far-field diffraction. While the classical algorithm was ambiguous and often converged to wrong solutions, quantum light produced a unique reconstruction with smaller errors and faster convergence. We attribute these improvements to a larger Hilbert space that constrains the algorithm.
DEFF Research Database (Denmark)
1996-01-01
with a simple one-to-one mapping between resolution elements of a spatial phase modulator and resolution elements of the generated intensity pattern is provided. According to the invention a method is provided for synthesizing an intensity pattern with low loss of electromagnetic energy, comprising spatial...... modulation of electromagnetic radiation with a spatial phase mask for modulation of the phase of the incident eletromagnetic radiation by phasor values of individual resolution elements of the spatial phase mask, each phasor value being determined in such a way that the values of the Fourier transformed......The invention relates to a method and a system for synthesizing a prescribed intensity pattern based on phase contrast imaging that is not based on the assumption of prior art methods that the pahase shift phi is less than 1 radian. An improved method based on a simple imaging operation...
Quantum Phase Liquids-Fermionic Superfluid without Phase Coherence
Wu, Ya-Jie; Zhou, Jiang; Kou, Su-Peng
2014-01-01
We investigate the two dimensional generalized attractive Hubbard model in a bipartite lattice, and and a "quantum phase liquid" phase, in which the fermions are paired but don't have phase coherence at zero temperature, in analogy to quantum spin liquid phase. Then, two types of topological quantum phase liquids with a small external magnetic field-Z2 quantum phase liquids and chiral quantum phase liquids-are discussed.
Phase transformation and diffusion
Kale, G B; Dey, G K
2008-01-01
Given that the basic purpose of all research in materials science and technology is to tailor the properties of materials to suit specific applications, phase transformations are the natural key to the fine-tuning of the structural, mechanical and corrosion properties. A basic understanding of the kinetics and mechanisms of phase transformation is therefore of vital importance. Apart from a few cases involving crystallographic martensitic transformations, all phase transformations are mediated by diffusion. Thus, proper control and understanding of the process of diffusion during nucleation, g
Energy Technology Data Exchange (ETDEWEB)
Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)
1996-11-01
Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.
DEFF Research Database (Denmark)
Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan C.
2017-01-01
A phase-locked loop (PLL) is a nonlinear negativefeedback control system that synchronizes its output in frequency as well as in phase with its input. PLLs are now widely used for the synchronization of power electronics-based converters and also for monitoring and control purposes in different...... engineering fields. In recent years, there have been many attempts to design more advanced PLLs for three-phase applications. The aim of this paper is to provide overviews of these attempts, which can be very useful for engineers and academic researchers....
Institute of Scientific and Technical Information of China (English)
LI Shichun
2004-01-01
Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.
Shurtleff, Richard
2008-01-01
A calculation based on flat spacetime symmetries shows how there can be two quantum phases. For one, extreme phase change determines a conventional classical trajectory and four-momentum, i.e. mass times four-velocity. The other phase occurs in an effective particle state, with the effective energy and momentum being the rate of change of the phase with respect to time and distance. A cosmic ray proton moves along a classical trajectory, but exists in an effective particle state with an effective energy that depends on the local gravitational potential. Assumptions are made so that a cosmic ray proton in an ultra-high energy state detected near the Earth was in a much less energetic state in interstellar space. A 300 EeV proton incident on the Earth was a 2 PeV proton in interstellar space. The model predicts such protons are in states with even more energy near the Sun than when near the Earth.
Chen, Chuan-Hung
2007-01-01
Unparticles proposed by Georgi carry CP conserving phases in their propagators. We demonstrate that these peculiar phases have an important impact on CP violation. Without including the strong QCD phases, we study the unparticle phase effects on the direct CP asymmetries in the exclusive decays of $\\bar B_d\\to \\pi^{+} \\pi^{-}$ and $B\\to \\pi K$, in which the flavor changing neutral currents are forbidden at tree level but induced by one-loop diagrams. Interesting and consistent results comparing to the data are obtained. In addition, we find that unparticles will significantly enhance the differential branching ratio of $b\\to s \\ell^{+} \\ell^{-}$ at the small invariant mass of $\\ell^{+} \\ell^{-}$. The forward-backward asymmetries for $b\\to s \\ell^{+} \\ell^{-}$ due to unparticles are also explored.
Katarina Anthony
2012-01-01
Building on the success of their feasibility phase, the CLIC test facility, CTF3, has just launched into a five-year project development phase. This will involve detailed performance optimisation studies, marking the project’s transition from pure research and development to prototyping and construction. CLIC accelerator modules under construction at CERN. “With the feasibility phase now complete, we have established that CLIC can be built,” says Roberto Corsini, CLIC Collaboration spokesperson. “Now we want to be sure that it can provide the luminosity and energy performance needed. We will be looking at the engineering, performance and cost of a real CLIC machine also seeing if we can reduce it.” CTF3’s second phase will focus on selected performance-related research areas for further investigation. The largest of these involves the construction and testing of several authentic CLIC accelerator modules that are currently being ...
Phase transitions modern applications
Gitterman, Moshe
2014-01-01
This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.
Thompson, Kenneth W.; Harrell, Marvin E.
1997-01-01
Describes an activity, designed to comply with the National Science Education Standards, that integrates science and mathematics concepts. Mathematical modeling of the moon's phases is employed to show students the role of mathematics in describing scientific phenomena. (DKM)
Marcin, Martin; Abramovici, Alexander
2008-01-01
The software of a commercially available digital radio receiver has been modified to make the receiver function as a two-channel low-noise phase meter. This phase meter is a prototype in the continuing development of a phase meter for a system in which radiofrequency (RF) signals in the two channels would be outputs of a spaceborne heterodyne laser interferometer for detecting gravitational waves. The frequencies of the signals could include a common Doppler-shift component of as much as 15 MHz. The phase meter is required to measure the relative phases of the signals in the two channels at a sampling rate of 10 Hz at a root power spectral density digital receiver. The input RF signal is first fed to the input terminal of an analog-to-digital converter (ADC). To prevent aliasing errors in the ADC, the sampling rate must be at least twice the input signal frequency. The sampling rate of the ADC is governed by a sampling clock, which also drives a digital local oscillator (DLO), which is a direct digital frequency synthesizer. The DLO produces samples of sine and cosine signals at a programmed tuning frequency. The sine and cosine samples are mixed with (that is, multiplied by) the samples from the ADC, then low-pass filtered to obtain in-phase (I) and quadrature (Q) signal components. A digital signal processor (DSP) computes the ratio between the Q and I components, computes the phase of the RF signal (relative to that of the DLO signal) as the arctangent of this ratio, and then averages successive such phase values over a time interval specified by the user.
Ahmad, Zahoor; Hanif, Muhammad
2013-01-01
The development of estimators of population parameters based on two-phase sampling schemes has seen a dramatic increase in the past decade. Various authors have developed estimators of population using either one or two auxiliary variables. The present volume is a comprehensive collection of estimators available in single and two phase sampling. The book covers estimators which utilize information on single, two and multiple auxiliary variables of both quantitative and qualitative nature. Th...
Institute of Scientific and Technical Information of China (English)
许可; 李未
1999-01-01
Phase transition is an important feature of SAT problem. For random k-SAT model, it is proved that as r（ratio of clauses to variables） increases, the structure of solutions will undergo a sudden change like satisfiability phase transition when r reaches a threshold point (r=rcr). This phenomenon shows that the satisfying truth assignments suddenly shift from being relatively different from each other to being very similar to each other.##属性不符
Electron microscope phase enhancement
Jin, Jian; Glaeser, Robert M.
2010-06-15
A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.
Optical Phase Imaging Using Synthetic Aperture Illumination and Phase Retrieval
Lee, Dennis J
2016-01-01
We perform quantitative phase imaging using phase retrieval to implement synthetic aperture imaging. Compared to digital holography, the developed technique is simpler, less expensive, and more stable.
Energy Technology Data Exchange (ETDEWEB)
Unknown
1999-11-01
The goals of the program are to develop a coal-fired high performance power generation system (HIPPS) that is capable of: thermal efficiency (HHV) {ge} 47%; NOx, SOx, and particulates {le} 10% NSPS (New Source Performance Standard); coal providing {ge} 65% of heat input; all solid wastes benign; and cost of electricity {le} 90% of present plants. Phase 1, which began in 1992, focused on the analysis of various configurations of indirectly fired cycles and on technical assessments of alternative plant subsystems and components, including performance requirements, developmental status, design options, complexity and reliability, and capital and operating costs. Phase 1 also included preliminary R and D and the preparation of designs for HIPPS commercial plants approximately 300 MWe in size. This Phase, Phase 2, had as its initial objective the development of a complete design base for the construction and operation of a HIPPS prototype plant to be constructed in Phase 3. As part of a descoping initiative, the Phase 3 program has been eliminated and work related to the commercial plant design has been ended. The rescoped program retained a program of engineering research and development focusing on high temperature heat exchangers, e.g. HITAF development (Task 2); a rescoped Task 6 that is pertinent to Vision 21 objectives and focuses on advanced cycle analysis and optimization, integration of gas turbines into complex cycles, and repowering designs; and preparation of the Phase 2 Technical Report (Task 8). This rescoped program deleted all subsystem testing (Tasks 3, 4,and 5) and the development of a site-specific engineering design and test plan for the HIPPS prototype plant (Task 7). Work reported herein is from: Task 2.1 HITAF Combustors; Task 2.2 HITAF Air Heaters; and Task 6 HIPPS Commercial Plant Design Update.
Polymorphic phase transition in Superhydrous Phase B
Koch-Müller, M.; Dera, P.; Fei, Y.; Hellwig, H.; Liu, Z.; Orman, J. Van; Wirth, R.
2005-09-01
We synthesized superhydrous phase B (shy-B) at 22 GPa and two different temperatures: 1200°C (LT) and 1400°C (HT) using a multi-anvil apparatus. The samples were investigated by transmission electron microscopy (TEM), single crystal X-ray diffraction, Raman and IR spectroscopy. The IR spectra were collected on polycrystalline thin-films and single crystals using synchrotron radiation, as well as a conventional IR source at ambient conditions and in situ at various pressures (up to 15 GPa) and temperatures (down to -180°C). Our studies show that shy-B exists in two polymorphic forms. As expected from crystal chemistry, the LT polymorph crystallizes in a lower symmetry space group ( Pnn2), whereas the HT polymorph assumes a higher symmetry space group ( Pnnm). TEM shows that both modifications consist of nearly perfect crystals with almost no lattice defects or inclusions of additional phases. IR spectra taken on polycrystalline thin films exhibit just one symmetric OH band and 29 lattice modes for the HT polymorph in contrast to two intense but asymmetric OH stretching bands and at least 48 lattice modes for the LT sample. The IR spectra differ not only in the number of bands, but also in the response of the bands to changes in pressure. The pressure derivatives for the IR bands are higher for the HT polymorph indicating that the high symmetry form is more compressible than the low symmetry form. Polarized, low-temperature single-crystal IR spectra indicate that in the LT-polymorph extensive ordering occurs not only at the Mg sites but also at the hydrogen sites.
Polymorphic Phase Transition in Superhydrous Phase B
Energy Technology Data Exchange (ETDEWEB)
Koch-Muller,M.; Dera, P.; Fei, Y.; Hellwig, H.; Liu, Z.; Van Orman, J.; Wirth, R.
2005-01-01
We synthesized superhydrous phase B (shy-B) at 22 GPa and two different temperatures: 1200 C (LT) and 1400 C (HT) using a multi-anvil apparatus. The samples were investigated by transmission electron microscopy (TEM), single crystal X-ray diffraction, Raman and IR spectroscopy. The IR spectra were collected on polycrystalline thin-films and single crystals using synchrotron radiation, as well as a conventional IR source at ambient conditions and in situ at various pressures (up to 15 GPa) and temperatures (down to -180 C). Our studies show that shy-B exists in two polymorphic forms. As expected from crystal chemistry, the LT polymorph crystallizes in a lower symmetry space group (Pnn2), whereas the HT polymorph assumes a higher symmetry space group (Pnnm). TEM shows that both modifications consist of nearly perfect crystals with almost no lattice defects or inclusions of additional phases. IR spectra taken on polycrystalline thin films exhibit just one symmetric OH band and 29 lattice modes for the HT polymorph in contrast to two intense but asymmetric OH stretching bands and at least 48 lattice modes for the LT sample. The IR spectra differ not only in the number of bands, but also in the response of the bands to changes in pressure. The pressure derivatives for the IR bands are higher for the HT polymorph indicating that the high symmetry form is more compressible than the low symmetry form. Polarized, low-temperature single-crystal IR spectra indicate that in the LT-polymorph extensive ordering occurs not only at the Mg sites but also at the hydrogen sites.
Shuryak, E V
1996-01-01
In the recent years we have learned that light quarks play a crucial role in QCD-like theories, transforming it to many different phases. We review what is known about them, both from lattice and non-lattice approaches. A particularly simple mechanism of the QCD chiral restoration phase transition is discussed first: it suggests that it is a transition from randomly placed tunneling events (instantons) at low T to strongly localized tunneling-anti-tunneling pairs at high T. Many features of the transition found on the lattice can be explained in this simple picture. Very relevant for RHIC, this approach predicts a strong non-perturbative interaction between quarks $above$ the phase transition. It also predicts that QGP-like phase sets in at $zero$ temperature, provided few more light quark flavors are added to QCD. Finally, we also discuss possible experimental signatures of the QCD phase transition. One issue is CERN dilepton data, possibly related with ``dropping'' masses of $\\rho, A_1$ mesons. Another is d...
Progress in ferrite phase shifters
Boyd, C. R., Jr.
1983-10-01
Advances in the technology of reciprocal ferrite phase shifters are outlined. Nonlatching rotary-field phase shifters have been produced with enhanced phase accuracy and modest control power. A significant quantity of dual-mode latching units has been built at 35 GHz, with good results. Both types of phase shifter can be adapted to perform other functions in addition to phase shifting. Examples of phase shifters that perform duplexing and polarization switching functions are given.
Single-phase to three-phase power conversion interface
Wu, Jinn-Chang; Wang, Yung-Shan; Jou, Hurng-Liahng; Lu, Wei-Tso
2016-07-01
This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface.
Kirchhoff migration without phases
Bardsley, Patrick; Guevara Vasquez, Fernando
2016-10-01
We present a simple, frequency domain, preprocessing step to Kirchhoff migration that allows the method to image scatterers when the wave field phase information is lost at the receivers, and only intensities are measured. The resulting imaging method does not require knowing the phases of the probing field or manipulating the phase of the wave field at the receivers. In a regime where the scattered field is small compared to the probing field, the problem of recovering the full-waveform scattered field from intensity data can be formulated as an embarrassingly simple least-squares problem. Although this only recovers the projection (on a known subspace) of the full-waveform scattered field, we show that, for high frequencies, this projection gives Kirchhoff images asymptotically identical to the images obtained with full waveform data. Our method can also be used when the source is modulated by a Gaussian process and autocorrelations are measured at an array of receivers.
Kirchhoff migration without phases
Bardsley, Patrick
2016-01-01
We present a simple, frequency domain, preprocessing step to Kirchhoff migration that allows the method to image scatterers when the wave field phase information is lost at the receivers, and only intensities are measured. The resulting imaging method does not require knowing the phases of the probing field or manipulating the phase of the wave field at the receivers. In a regime where the scattered field is small compared to the probing field, the problem of recovering the full-waveform scattered field from intensity data can be formulated as an embarrassingly simple least-squares problem. Although this only recovers the projection (on a known subspace) of the full-waveform scattered field, we show that, for high frequencies, this projection gives Kirchhoff images asymptotically identical to the images obtained with full waveform data. Our method can also be used when the source is modulated by a Gaussian process and autocorrelations are measured at an array of receivers.
DEFF Research Database (Denmark)
Khandige, Surabhi; Møller-Jensen, Jakob
2016-01-01
Surface fimbriae of pathogenic Escherichia coli facilitate sensing, adhesion and even invasion of host epithelial cells. While it is known that the pathogen has the potential to express a plethora of fimbrial variants susceptible to rapid phase ON/OFF variation, it is an open question if the fimb......Surface fimbriae of pathogenic Escherichia coli facilitate sensing, adhesion and even invasion of host epithelial cells. While it is known that the pathogen has the potential to express a plethora of fimbrial variants susceptible to rapid phase ON/OFF variation, it is an open question...... if the fimbrial diversity seen at the population level is the product of random stochasticity or a concerted effort based on active communication. Here we discuss the possibility of a mechanism alternative to a stochastic fimbrial phase variation model affecting the dynamics of a heterogeneous population....
Energy Technology Data Exchange (ETDEWEB)
Gulminelli, F
2003-05-01
In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory; we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. (author)
Understanding quantum phase transitions
Carr, Lincoln
2010-01-01
Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth
Bowers, Michael T
1979-01-01
Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well
Compressive Phase Contrast Tomography
Maia, F R N C; Marchesini, S; Padmore, H A; Parkinson, D Y; Pien, J; Schirotzek, A; Yang, C; 10.1117/12.861946
2010-01-01
When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher con- trast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).
Phase transitions in geometrothermodynamics
Quevedo, H; Taj, S; Vazquez, A
2010-01-01
Using the formalism of geometrothermodynamics, we investigate the geometric properties of the equilibrium manifold for diverse thermodynamic systems. Starting from Legendre invariant metrics of the phase manifold, we derive thermodynamic metrics for the equilibrium manifold whose curvature becomes singular at those points where phase transitions of first and second order occur. We conclude that the thermodynamic curvature of the equilibrium manifold, as defined in geometrothermodynamics, can be used as a measure of thermodynamic interaction in diverse systems with two and three thermodynamic degrees of freedom.
Kopaev, YuV
1992-01-01
Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele
Čermák, J
2008-01-01
This special-topic book, devoted to ""Solid Phase Transformations"" , covers a broad range of phenomena which are of importance in a number of technological processes. Most commercial alloys undergo thermal treatment after casting, with the aim of imparting desired compositions and/or optimal morphologies to the component phases. In spite of the fact that the topic has lain at the center of physical metallurgy for a long time, there are numerous aspects which are wide open to potential investigative breakthroughs. Materials with new structures also stimulate research in the field, as well as n
Entropy of phase measurement quantum phase via quadrature measurement
My, R; My, Robert; Uni, Palacky
1995-01-01
The content of phase information of an arbitrary phase--sensitive measurement is evaluated using the maximum likelihood estimation. The phase distribution is characterized by the relative entropy--a nonlinear functional of input quantum state. As an explicit example the multiple measurement of quadrature operator is interpreted as quantum phase detection achieving the ultimate resolution predicted by the Fisher information.
DEFF Research Database (Denmark)
Carlsen, Lars; Egsgaard, Helge
1982-01-01
The unimolecular gas-phase thermolyses of 1,2,3-oxadithiolan 2-oxide and thiiran 1-oxide have been studied by the flash vacuum thermolysis–field ionization mass spectrometry (f.v.t.–f.i.m.s.) technique in the temperature range from 1 043 to 1 404 K. The reactions are rationalized in terms...
DEFF Research Database (Denmark)
Carlsen, Lars; Egsgaard, Helge
1982-01-01
The unimolecular gas-phase thermolyses of the four methyl and ethyl monothioacetates (5)–(8) have been studied by the flash vacuum thermolysis–field ionization mass spectrometry technique in the temperature range 883–1 404 K. The types of reactions verified were keten formation, thiono...
DEFF Research Database (Denmark)
Carlsen, Lars; Egsgaard, Helge; Schaumann, Ernst
1980-01-01
The unimolecular gas-phase thermolytic decomposition of three silylated thionocarboxylic acid derivatives (2b), (3), and (8) have been studied by the flash vacuum thermolysis–field ionization mass spectrometry technique in the temperature range from 783 to 1 404 K in order to elucidate its possib...
Phase sensitivity in electroreception.
Heiligenberg, W; Altes, R A
1978-03-03
The gymnotoid electric fish Hypopomus artedi discriminates between electric stimulus pulses with identical spectral amplitudes but different spectral phase functions. Behavioral results can be explained on the assumption that electroreception is based on a linear filter, approximately matched to the species' electric organ discharge. The impulse response of the appropriate matched filter, in fact, resembles the known impulse response of the electroreceptors involved.
Directory of Open Access Journals (Sweden)
Nobuyuki Kenmochi
1996-01-01
w is constrained to have double obstacles σ*≤w≤σ* (i.e., σ* and σ* are the threshold values of w. The objective of this paper is to discuss the semigroup {S(t} associated with the phase separation model, and construct its global attractor.
Vinh, Megan; Lucas, Anne; Taylor, Cornelia; Kelley, Grace; Kasprzak, Christina
2014-01-01
This roadmap provides a description of the activities involved in the development of the State Systemic Improvement Plan (SSIP) (SPP/APR Indicators C11 and B17) due to the Office of Special Education Programs (OSEP) on April 1, 2015. The roadmap is intended to support states with completing Phase I of the SSIP process. This document provides…
Phase separation micro molding
Vogelaar, Laura
2005-01-01
The research described in this thesis concerns the development of a new microfabrication method, Phase Separation Micro Molding (PSμM). While microfabrication is still best known from semiconductor industry, where it is used to integrate electrical components on a chip, the scope has immensely expan
DEFF Research Database (Denmark)
Boone, Aaron; de Rosnay, Patricia; Beljaars, Anton;
This report describes the experimental setup and results of the Phase 1 (i.e. the Regional Scale) of the AMMA (African Monsoon Multidisciplinary Analysis) Land surface Model Intercomparison Project (ALMIP). It is part of the AMMA-EU (European Union) and API (Action Programmée Interorganisme: A...
DEFF Research Database (Denmark)
Nilsson, Torben
The objective of this study has been to develop new analytical methods using the rapid, simple and solvent-free extraction technique solid-phase microextraction (SPME) for the quantitative analysis of organic pollutants at trace level in drinking water and environmental samples. The dynamics...
DEFF Research Database (Denmark)
Margheritini, Lucia; Taraborrelli, Valeria Taraborrelli
Margheritini and Valeria Taraborrelli(valeria.taraborrelli@hotmail.it) with a total of 3 day visit from the developers. Laboratory tests in irregular waves will be performed by Lucia Margheritini. The report is aimed at the first stage testing of the Rolling Cylinder wave energy device. This phase includes...
Basinger, Scott A.; Bikkannavar, Siddarayappa; Cohen, David; Green, Joseph J.; Lou, John; Ohara, Catherine; Redding, David; Shi, Fang
2008-01-01
Adaptive MGS Phase Retrieval software uses the Modified Gerchberg-Saxton (MGS) algorithm, an image-based sensing method that can turn any focal plane science instrument into a wavefront sensor, avoiding the need to use external metrology equipment. Knowledge of the wavefront enables intelligent control of active optical systems.
Photoinduced phase transitions
Nasu, K
2004-01-01
A new class of insulating solids was recently discovered. Whenirradiated by a few visible photons, these solids give rise to amacroscopic excited domain that has new structural and electronicorders quite different from the starting ground state. This occurrenceis called "photoinduced phase transition", and this multi-authoredbook reviews recent theoretical and experimental studies of this newphenomenon.
Phase Computations and Phase Models for Discrete Molecular Oscillators.
Demir, Alper; Şuvak, Önder
2012-01-01
RESEARCH Open Access Phase computations and phase models for discrete molecular oscillators Onder Suvak* and Alper Demir Abstract Background: Biochemical oscillators perform crucial functions in cells, e.g., they set up circadian clocks. The dynamical behavior of oscillators is best described and analyzed in terms of the scalar quantity, phase. A rigorous and useful definition for phase is based on the so-called isochrons of oscillators. Phase computation techniques for ...
Energy Technology Data Exchange (ETDEWEB)
Schuknecht, Nate [Project Manager; White, David [Principle Investigator; Hoste, Graeme [Research Engineer
2014-09-11
The SkyTrough DSP will advance the state-of-the-art in parabolic troughs for utility applications, with a larger aperture, higher operating temperature, and lower cost. The goal of this project was to develop a parabolic trough collector that enables solar electricity generation in the 2020 marketplace for a 216MWe nameplate baseload power plant. This plant requires an LCOE of 9¢/kWhe, given a capacity factor of 75%, a fossil fuel limit of 15%, a fossil fuel cost of $6.75/MMBtu, $25.00/kWht thermal storage cost, and a domestic installation corresponding to Daggett, CA. The result of our optimization was a trough design of larger aperture and operating temperature than has been fielded in large, utility scale parabolic trough applications: 7.6m width x 150m SCA length (1,118m2 aperture), with four 90mm diameter × 4.7m receivers per mirror module and an operating temperature of 500°C. The results from physical modeling in the System Advisory Model indicate that, for a capacity factor of 75%: The LCOE will be 8.87¢/kWhe. SkyFuel examined the design of almost every parabolic trough component from a perspective of load and performance at aperture areas from 500 to 2,900m2. Aperture-dependent design was combined with fixed quotations for similar parts from the commercialized SkyTrough product, and established an installed cost of $130/m2 in 2020. This project was conducted in two phases. Phase I was a preliminary design, culminating in an optimum trough size and further improvement of an advanced polymeric reflective material. This phase was completed in October of 2011. Phase II has been the detailed engineering design and component testing, which culminated in the fabrication and testing of a single mirror module. Phase II is complete, and this document presents a summary of the comprehensive work.
Phase Transitions of Simple Systems
Berry, Stephen
2008-01-01
This monograph develops a unified microscopic basis for phases and phase changes of bulk matter and small systems in terms of classical physics. The origins of such phase changes are derived from simple but physically relevant models of how transitions between rigid crystalline, glassy and fluid states occur, how phase equilibria arise, and how bulk properties evolve from those of small systems.
DEFF Research Database (Denmark)
Mogensen, P.C.; Glückstad, J.
2000-01-01
We have implemented a phase-only optical encryption and decryption system with a readout based on the generalized phase-contrast method. The experimental system has been implemented with Liquid-crystal spatial light modulators to generate binary phase-encrypted masks and a decrypting key. A phase...
Phase estimation in optical interferometry
Rastogi, Pramod
2014-01-01
Phase Estimation in Optical Interferometry covers the essentials of phase-stepping algorithms used in interferometry and pseudointerferometric techniques. It presents the basic concepts and mathematics needed for understanding the phase estimation methods in use today. The first four chapters focus on phase retrieval from image transforms using a single frame. The next several chapters examine the local environment of a fringe pattern, give a broad picture of the phase estimation approach based on local polynomial phase modeling, cover temporal high-resolution phase evaluation methods, and pre
Gulminelli, F.
2004-11-01
In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory, we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermostatistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball and INDRA array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. Coexistence de phase dans les noyaux Ce papier présente une revue de la théorie générale des transitions de phase du premier ordre dans les petits systèmes, avec une attention particulière aux probl
Phase noise reduction by self-phase locking in semiconductor lasers using phase conjugate feedback
DEFF Research Database (Denmark)
Petersen, Lykke; Gliese, Ulrik Bo; Nielsen, Torben Nørskov
1994-01-01
A theoretical analysis of the behavior of the frequency/phase noise of semiconductor lasers with external phase conjugate feedback is presented. It is shown that the frequency noise is drastically reduced even for lasers with butt-coupled phase conjugate mirrors. In this laser system, the phase...
Emergence and Phase Transitions
Sikkema, Arnold
2006-05-01
Phase transitions are well defined in physics through concepts such as spontaneous symmetry breaking, order parameter, entropy, and critical exponents. But emergence --- also exhibiting whole-part relations (such as top-down influence), unpredictability, and insensitivity to microscopic detail --- is a loosely-defined concept being used in many disciplines, particularly in psychology, biology, philosophy, as well as in physics[1,2]. I will review the concepts of emergence as used in the various fields and consider the extent to which the methods of phase transitions can clarify the usefulness of the concept of emergence both within the discipline of physics and beyond.1. Robert B. Laughlin, A Different Universe: Reinventing Physics from the Bottom Down (New York: Basic Books, 2005). 2. George F.R. Ellis, ``Physics and the Real World'', Physics Today, vol. 58, no. 7 (July 2005) pp. 49-54.
2009-11-01
based on the Model-View-Controller ( MVC ) design pattern . New events created in SKIWeb activate a database trigger that captures the id numbers of the...Phase 2, SKIPAL incorporated the Spring Web MVC framework to facilitate future integration efforts with SKIWeb. Spring Web MVC is a web framework...Nonparametric Analysis of Fingerprint Data on Large Data Sets,” Pattern Recognition, vol. 40, no. 9, pp. 2574-2584, Sep. 2007. 4. Davis, J. and Goadrich
Phase Field Fracture Mechanics.
Energy Technology Data Exchange (ETDEWEB)
Robertson, Brett Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-11-01
For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.
Phases, phase equilibria, and phase rules in low-dimensional systems
Energy Technology Data Exchange (ETDEWEB)
Frolov, T., E-mail: timfrol@berkeley.edu [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Mishin, Y., E-mail: ymishin@gmu.edu [Department of Physics and Astronomy, MSN 3F3, George Mason University, Fairfax, Virginia 22030 (United States)
2015-07-28
We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.
Phases, phase equilibria, and phase rules in low-dimensional systems.
Frolov, T; Mishin, Y
2015-07-28
We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.
Fodor, Z
2000-01-01
Recent developments on the four dimensional (4d) lattice studies of the finite temperature electroweak phase transition (EWPT) are summarized. The phase diagram is given in the continuum limit. The finite temperature SU(2)-Higgs phase transition is of first order for Higgs-boson masses m/sub H/<66.5+or-1.4 GeV. Above this endpoint only a rapid cross-over can be seen. The full 4d result agrees completely with that of the dimensional reduction approximation. The Higgs-boson endpoint mass in the standard model (SM) would be 72.1+or-1. 4 GeV. Taking into account the LEP Higgs-boson mass lower bound excludes any EWPT in the SM. A one-loop calculation of the static potential in the SU(2)-Higgs model enables a precise comparison between lattice simulations and perturbative results. The most popular extension of the SM, the minimal supersymmetric SM (MSSM) is also studied on 4d lattices. (17 refs).
Compactification on phase space
Lovelady, Benjamin; Wheeler, James
2016-03-01
A major challenge for string theory is to understand the dimensional reduction required for comparison with the standard model. We propose reducing the dimension of the compactification by interpreting some of the extra dimensions as the energy-momentum portion of a phase-space. Such models naturally arise as generalized quotients of the conformal group called biconformal spaces. By combining the standard Kaluza-Klein approach with such a conformal gauge theory, we may start from the conformal group of an n-dimensional Euclidean space to form a 2n-dimensional quotient manifold with symplectic structure. A pair of involutions leads naturally to two n-dimensional Lorentzian manifolds. For n = 5, this leaves only two extra dimensions, with a countable family of possible compactifications and an SO(5) Yang-Mills field on the fibers. Starting with n=6 leads to 4-dimensional compactification of the phase space. In the latter case, if the two dimensions each from spacetime and momentum space are compactified onto spheres, then there is an SU(2)xSU(2) (left-right symmetric electroweak) field between phase and configuration space and an SO(6) field on the fibers. Such a theory, with minor additional symmetry breaking, could contain all parts of the standard model.
Rajagopal, K
1999-01-01
The QCD vacuum in which we live, which has the familiar hadrons as its excitations, is but one phase of QCD, and far from the simplest one at that. One way to better understand this phase and the nonperturbative dynamics of QCD more generally is to study other phases and the transitions between phases. We are engaged in a voyage of exploration, mapping the QCD phase diagram as a function of temperature T and baryon number chemical potential mu . Because of asymptotic freedom, the high temperature and high baryon density phases of QCD are more simply and more appropriately described in terms of quarks and gluons as degrees of freedom, rather than hadrons. The chiral symmetry breaking condensate which characterizes the vacuum phase melts away. At high densities, quarks form Cooper pairs and new condensates develop. The formation of such superconducting phases requires only weak attractive interactions; these phases may nevertheless break chiral symmetry and have excitations which are indistinguishable from thos...
Design of a Phase Detector for the Phase Probe
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>Phase probe system is an important part of the cyclotron beam diagnostic systems. Inside the cyclotron, the beam has to be in phase with RF. Because of the mechanical deformation and instability of
Hosten, O.; Krishnakumar, R.; Engelsen, N. J.; Kasevich, M. A.
2016-06-01
Quantum metrology exploits entangled states of particles to improve sensing precision beyond the limit achievable with uncorrelated particles. All previous methods required detection noise levels below this standard quantum limit to realize the benefits of the intrinsic sensitivity provided by these states. We experimentally demonstrate a widely applicable method for entanglement-enhanced measurements without low-noise detection. The method involves an intermediate quantum phase magnification step that eases implementation complexity. We used it to perform squeezed-state metrology 8 decibels below the standard quantum limit with a detection system that has a noise floor 10 decibels above the standard quantum limit.
Cantera, Rodrigo G; Leza, María G; Bachiller, Carmen M
2002-10-01
In this report we describe the preparation and characterization of four polymorphic forms of tenoxicam; they are, three 1:1 stoichiometric solvates with acetonitrile, dioxane, and N,N-dimethylformamide, and an amorphous phase obtained by recrystallization in various solvents. Polymorph IV and solvates with dioxane and N,N-dimethylformamide are reported for the first time in this paper. In addition, three solvates were crystallized in acetone, ethyl acetate, and isopropyl alcohol. These solid forms were characterized by X-ray powder diffraction, differential scanning calorimetry, infrared spectroscopy, thermogravimetry, optical microscopy, and elemental analysis. Solid-state properties, intrinsic dissolution rate, and dissolution kinetics from formulated tablets are also provided.
Incommensurate phase transitions
Energy Technology Data Exchange (ETDEWEB)
Currat, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-11-01
We review the characteristic aspects of modulated crystals from the point of view of inelastic neutron scattering. We discuss the phenomenological Landau theory of the normal-to-incommensurate displacive instability and its predictions concerning the fluctuation spectrum of the modulated phase. General results on the form of the normal-mode eigenvectors and on the inelastic scattering channels through which they couple to the probe are established using the superspace approach. We illustrate these results on a simple discrete model symmetry and we review available inelastic neutron scattering data on several displacively modulated compounds. (author) 21 figs., 73 refs.
Qureshi, Moinuddin K
2011-01-01
As conventional memory technologies such as DRAM and Flash run into scaling challenges, architects and system designers are forced to look at alternative technologies for building future computer systems. This synthesis lecture begins by listing the requirements for a next generation memory technology and briefly surveys the landscape of novel non-volatile memories. Among these, Phase Change Memory (PCM) is emerging as a leading contender, and the authors discuss the material, device, and circuit advances underlying this exciting technology. The lecture then describes architectural solutions t
Athena: Assessment Phase Activities
Lumb, David; Ayre, Mark
2015-09-01
The Athena mission concept has been proposed by the community in response to science themes of the Hot and Energetic Universe. Unlike other, competitive, mission selection exercises this "Large" class observatory mission has essentially been pre-selected. Nevertheless it has to be demonstrated that Athena meets the programmatic constraints of 1Bn euro cost cap, and a readiness level appropriate for formal mission adoption by the end 2019. This should be confirmed through a Phase A study conducted with two parallel industry activities. We describe the technical and programmatic content of these and latest progress in space and ground segment definition.
Collective neurodynamics: Phase diagram
Ovchinnikov, Igor V.; Li, Wenyuan; Schwartz, Robert N.; Hudson, Andrew E.; Meier, Karlheinz; Wang, Kang L.
2016-01-01
Here, we conceptualize the phase diagram of collective short-term bio-chemo-electric component of neurodynamics (S-ND) on the parameter space of externally, e.g., pharmacologically, controllable single-neuron parameters such as the resting potential and/or firing threshold, repolarization time, etc. This concept may become a useful tool for the systematization of knowledge in anesthesiology and provide a fruitful venue for future studies of the high-level S-ND functionalities such as short-te...
Phase retrieval using nonlinear diversity.
Lu, Chien-Hung; Barsi, Christopher; Williams, Matthew O; Kutz, J Nathan; Fleischer, Jason W
2013-04-01
We extend the Gerchberg-Saxton algorithm to phase retrieval in a nonlinear system. Using a tunable photorefractive crystal, we experimentally demonstrate the noninterferometric technique by reconstructing an unknown phase object from optical intensity measurements taken at different nonlinear strengths.
Viraj Suvarna
2010-01-01
Not all Phase IV studies are post-marketing surveillance (PMS) studies but every PMS study is a phase IV study. Phase IV is also an important phase of drug development. In particular, the real world effectiveness of a drug as evaluated in an observational, non-interventional trial in a naturalistic setting which complements the efficacy data that emanates from a pre-marketing randomized controlled trial (RCT). No matter how many patients are studied pre-marketing in a controlled environment, ...
Phase Referencing in Optical Interferometry
Mercedes E. Filho; Garcia, Paulo; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie
2008-01-01
One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two extremes of phase corruption by the atmosphere. While in radio it is possible to obtain calibrated phases for the science objects, in the optical this is currently not possible. Instead, optical interferometry has relied on closure phase techniques to produce...
On the degenerate phase boundaries
Ma, Y; Kuang, Z; Ma, Yongge; Liang, Canbin; Kuang, Zhiquan
1999-01-01
The structure of the phase boundary between degenerate and non-degenerate regions in Ashtekar's gravity has been studied by Bengtsson and Jacobson who conjectured that the "phase boundary" should always be null. In this paper, we reformulate the reparametrization procedure in the mapping language and distinguish a phase boundary from its image. It is shown that the image has to be null, while the nullness of the phase boundary requries more suitable criterion.
AL-Rabab’ah, Mohammad A.; Bustani, Mohammad A.; Khraisat, Ameen S.; Sawair, Faleh A.
2016-01-01
Objectives To assess the knowledge of Jordanian dentists toward phase down of dental amalgam as recommended by the Minamata Convention, and their training and competency in placing posterior composites. Methods This study was conducted through structured questionnaire interviews with randomly selected cohort of dentists in Jordan between March 2015 and June 2015. Out of 230 dentists who were invited, 196 (85.2%) agreed to participate. Dentists were asked if they know about the Minamata Convention. They were also asked about their training in placement of posterior composite. Results Out of the 196 interviewed, only 13.8% know about Minamata Convention and 17% had an undergraduate training in favor of placing composites in posterior teeth. Approximately 50% of those dentists were not trained in using rubber dam when placing posterior composites, while only 38.3% had training in sectional matrix placement. Undergraduate training did not influence (p=0.00) the dentists’ decision to remove old amalgam based on patient’s demands. Only 28.1% were of the opinion of discontinuing the use of amalgam due to its alleged health and environmental hazards. There was no general agreement on the type of composite, liner, and bonding strategy when placing posterior composites. Conclusion Dentists are not well informed on the Minamata Convention and the phase down of amalgam. Training in posterior composite placement should be given more room in undergraduate curriculum and continuous dental education. PMID:27874155
Nonlinear phased array imaging
Croxford, Anthony J.; Cheng, Jingwei; Potter, Jack N.
2016-04-01
A technique is presented for imaging acoustic nonlinearity within a specimen using ultrasonic phased arrays. Acoustic nonlinearity is measured by evaluating the difference in energy of the transmission bandwidth within the diffuse field produced through different focusing modes. The two different modes being classical beam forming, where delays are applied to different element of a phased array to physically focus the energy at a single location (parallel firing) and focusing in post processing, whereby one element at a time is fired and a focused image produced in post processing (sequential firing). Although these two approaches are linearly equivalent the difference in physical displacement within the specimen leads to differences in nonlinear effects. These differences are localized to the areas where the amplitude is different, essentially confining the differences to the focal point. Direct measurement at the focal point are however difficult to make. In order to measure this the diffuse field is used. It is a statistical property of the diffuse field that it represents the total energy in the system. If the energy in the diffuse field for both the sequential and parallel firing case is measured then the difference between these, within the input signal bandwidth, is largely due to differences at the focal spot. This difference therefore gives a localized measurement of where energy is moving out of the transmission bandwidth due to nonlinear effects. This technique is used to image fatigue cracks and other damage types undetectable with conventional linear ultrasonic measurements.
2006-01-01
This month has seen the launch of the second two-year phase of the Enabling Grids for E-sciencE project (EGEE-II), with a transition meeting for the partners held at CERN on 12-13 April. Co-funded by the European Commission and coordinated by CERN, the EGEE project is providing an international Grid computing infrastructure - now numbering some 200 sites and 20 000 CPUs in 39 countries - to support the scientific community worldwide. 'We are all very happy about the smooth start of the second phase of EGEE,' said Project Director Bob Jones. 'The project builds on the successes of its first two years and we are now focussing on the stability of the deployed infrastructure. Growing beyond our pilot application areas of HEP and biomedicine, we now see increasing use by researchers from other fields. Recently we've added finance and fusion to the list of disciplines we support, and we are always looking for new users.' More information on EGEE can be found at www.eu-egee.org.
Energy Technology Data Exchange (ETDEWEB)
Roessner, Simon
2009-04-09
Quantum Chromodynamics (QCD) is the theory of the strong interaction within the Standard Model of elementary particles. Today's research in this area dedicates substantial resources to numeric solutions of the QCD field equations and experimental programs exploring the phases of QCD. This thesis proceeds along a complementary line - that of modelling QCD, with the aim of identifying its dominant degrees of freedom. This is possible by minimally coupling effective potentials for the Polyakov loop to Nambu-Jona-Lasinio models using temporal background fields to model chiral symmetry breaking respecting colour confinement. The fermion sign problem resulting from the minimal coupling is addressed in this work establishing a novel, systematically ordered approach. The modifications to the approximative order parameter of colour confinement, the Polyakov loop, are in direct connection with the fermion sign problem. Furthermore an effective coupling of quark densities of different flavours is induced. This mechanism, most likely also present in QCD, produces finite contributions to flavour off diagonal susceptibilities. Susceptibilities are amongst the most promising physical quantities for the experimental exploration of the phase transition at high temperatures and densities. (orig.)
Worldwide phase management process
Hapeman, Garry J.
1992-05-01
Most, if not all projects, whether it is the development of a new product, a new process or fundamental research, if it requires creativity, ingenuity and some luck to meet the project objectives, will be started with a degree of uncertainty. However, in spite of this uncertainty, Project Sponsors and Company Management often require Project Managers to commit to delivery dates, performance metrics, development dollars, capital dollars, etc. Unfortunately, these early commitments are usually not able to be upheld, which leads to one or more iterations of requests for additional funding, changes to functional requirements, schedule extensions and possible compromises in the quality of the project. These "go arounds" between Project Managers and Project Sponsors can lead to much frustration, are time consuming, and often result in a compromise to the project objectives. Through the use of a Phased Development Approach, we have been able to create a more reasonable method for dealing with project risk and uncertainty. Worldwide Phase Management for New Product Development is a process that has significantly improved the establishment of delivery dates, forecasts for funding requirements, communication and understanding of expectations between a Project Team and the Project Sponsor. In addition, a consistent methodology for New Development Projects has resulted in a more productive development environment that results in shorter product development life cycles.
Phase behavior of hard particles
Duijneveldt, J.S. van; Lekkerkerker, H.N.W.
1995-01-01
The phase behavior of hard particles and mixtures thereof is reviewed. Special attention is given to a lattice model consisting of hard hexagons and points on a triangular lattice. This model appears to have two disordered phases and an ordered phase.
Phase extraction based on sinusoidal extreme strip phase shifting method
Hui, Mei; Liu, Ming; Dong, Liquan; Liu, Xiaohua; Zhao, Yuejin
2015-08-01
Multiple synthetic aperture imaging can enlarge pupil diameter of optical systems, and increase system resolution. Multiple synthetic aperture imaging is a cutting-edge topic and research focus in recent years, which is prospectively widely applied in fields like astronomical observations and aerospace remote sensing. In order to achieve good imaging quality, synthetic aperture imaging system requires phase extraction of each sub-aperture and co-phasing of whole aperture. In the project, an in-depth study about basic principles and methods of segments phase extraction was done. The study includes: application of sinusoidal extreme strip light irradiation phase shift method to extract the central dividing line to get segment phase extraction information, and the use of interference measurement to get the aperture phase extraction calibration coefficients of spherical surface. Study about influence of sinusoidal extreme strip phase shift on phase extraction, and based on sinusoidal stripe phase shift from multiple linear light sources of the illumination reflected image, to carry out the phase shift error for inhibiting the effect in the phase extracted frame.
Geometric phase and Pancharatnam phase induced by light wave polarization
Lages, J; Vigoureux, J -M
2013-01-01
We use the quantum kinematic approach to revisit geometric phases associated with polarizing processes of a monochromatic light wave. We give the expressions of geometric phases for any, unitary or non-unitary, cyclic or non-cyclic transformations of the light wave state. Contrarily to the usually considered case of absorbing polarizers, we found that a light wave passing through a polarizer may acquire in general a non zero geometric phase. This geometric phase exists despite the fact that initial and final polarization states are in phase according to the Pancharatnam criterion and can not be measured using interferometric superposition. Consequently, there is a difference between the Pancharatnam phase and the complete geometric phase acquired by a light wave passing through a polarizer. We illustrate our work with the particular example of total reflection based polarizers.
A modified phase-coding method for absolute phase retrieval
Xing, Y.; Quan, C.; Tay, C. J.
2016-12-01
Fringe projection technique is one of the most robust tools for three dimensional (3D) shape measurement. Various fringe projection methods have been proposed for addressing different issues in profilometry and phase-coding is one such technique employed to determine fringe orders for absolute phase retrieval. However this method is prone to fringe order error, while dealing with high-frequency fringes. This paper studies phase error introduced by system non-linearity in phase-coding and provides a mathematical model to obtain the maximum number of achievable codewords in a given scheme. In addition, a modified phase-coding method is also proposed for phase error compensation. Experimental study validates the theoretical analysis on the maximum number of achievable codewords and the performance of the modified phase-coding method is also illustrated.
Brazhkin, Vadim V.
2006-07-01
Concepts of a 'phase' and a 'phase transition' are discussed for stable and metastable states of matter. While condensed matter physics primarily considers equilibrium states and treats metastable phases as exceptions, organic chemistry overwhelmingly deals with metastable states. It is emphasized that many simple light-element compounds — including most hydrocarbons; nitrogen oxides, hydrides, and carbides; carbon monoxide CO; alcohols and glycerin — are also metastable at normal pressure in the sense that they do not correspond to a minimum Gibbs free energy for a given chemical composition. At moderate temperatures and pressures, the phase transformations for these metastable phases are reversible with the fulfilment of all laws of equilibrium thermodynamics over the entire range of experimentally accessible times. At sufficiently high pressures (> 1-10 GPa), most of the metastable molecular phases irreversibly transform to lower-energy polymer phases, stable or metastable. These transitions do not correspond to the equality of the Gibbs free energy for the involved phases before and after the transition and so they are not first-order in the 'classical' sense. At normal pressure, the resulting polymer phases can exist at temperatures above the melting point of the original metastable molecular phase, as the examples of polyethylene and polymerized CO dramatically illustrate. As pressure is increased further to 20-50 GPa, the PV contribution to Gibbs free energy gives rise to stable high-density atomic phases. Many of the intermediate-energy polymer phases can likely be synthesized by methods of 'classical' chemistry at normal pressure.
Energy Technology Data Exchange (ETDEWEB)
R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin
2010-09-01
The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel cycle options. An integrated nuclear fuel cycle option is defined in this study as including all aspects of the entire nuclear fuel cycle, from obtaining natural resources for fuel to the ultimate disposal of used nuclear fuel (UNF) or radioactive wastes. Issues such as nuclear waste management, especially the increasing inventory of used nuclear fuel, the current uncertainty about used fuel disposal, and the risk of nuclear weapons proliferation have contributed to the reluctance to expand the use of nuclear power, even though it is recognized that nuclear power is a safe and reliable method of producing electricity. In this Options Study, current, evolutionary, and revolutionary nuclear energy options were all considered, including the use of uranium and thorium, and both once-through and recycle approaches. Available information has been collected and reviewed in order to evaluate the ability of an option to clearly address the challenges associated with the current implementation and potential expansion of commercial nuclear power in the United States. This Options Study is a comprehensive consideration and review of fuel cycle and technology options, including those for disposal, and is not constrained by any limitations that may be imposed by economics, technical maturity, past policy, or speculated future conditions. This Phase II report is intended to be used in conjunction with the Phase I report, and much information in that report is not repeated here, although some information has been updated to reflect recent developments. The focus in this Options Study was to
Blanchet, Steve
2007-01-01
I present here a concise summary of the preprint arXiv:0707.3024, written in collaboration with A. Anisimov and P. Di Bari. There we discuss leptogenesis when {\\em CP} violation stems exlusively from the Dirac phase in the PMNS mixing matrix. Under this assumption it turns out that the situation is very constrained when a hierarchical heavy right-handed (RH) neutrino spectrum is considered: the allowed regions are small and the final asymmetry depends on the initial conditions. On the other hand, for a quasi-degenerate spectrum of RH neutrinos, the {\\em CP} asymmetry can be enhanced and the situation becomes much more favorable, with no dependence on the initial conditions. Interestingly, in the extreme case of resonant leptogenesis, in order to match the observed baryon asymmetry of the Universe, we obtain a lower bound on \\sin \\q_{13} which depends on the lightest active neutrino mass m_1.
Coherent imaging without phases
Moscoso, Miguel; Papanicolaou, George
2015-01-01
In this paper we consider narrow band, active array imaging of weak localized scatterers when only the intensities are recorded at an array with N transducers. We consider that the medium is homogeneous and, hence, wave propagation is fully coherent. This work is an extension of our previous paper, where we showed that using linear combinations of intensity-only measurements imaging of localized scatterers can be carried out efficiently using MUSIC or sparsity promoting optimization. Here we show the same strategy can be accomplished with only 3N-2 illuminations, therefore reducing enormously the data acquisition process. Furthermore, we show that in the paraxial regime one can form the images by using six illuminations only. In particular, this paraxial regime includes Fresnel and Fraunhofer diffraction. The key point of this work is that if one controls the illuminations, imaging with intensity-only can be easily reduced to a imaging with phases and, therefore, one can apply standard imaging techniques. Det...
Directory of Open Access Journals (Sweden)
Marco Liuni
2013-08-01
Full Text Available For a broad range of sound transformations, quality is measured according to the common expectation about the result: if a male’s voice has to be changed in a female’s one, there exists a common reference for the perceptive evaluation of the result; the same holds if an instrumental sound has to be made longer, or shorter. Following the argument in Röbel, “Between Physics and Perception: Signal Models for High Level Audio Processing”, a fundamental requirement for these transformation algorithms is their need of signal models that are strongly linked to perceptually relevant physical properties of the sound source. This paper is a short survey about the phase vocoder technique, together with its extensions and improvements relying on appropriate sound models, which have led to high level audio processing algorithms.
Hockney, Roger
1987-01-01
Algorithmic phase diagrams are a neat and compact representation of the results of comparing the execution time of several algorithms for the solution of the same problem. As an example, the recent results are shown of Gannon and Van Rosendale on the solution of multiple tridiagonal systems of equations in the form of such diagrams. The act of preparing these diagrams has revealed an unexpectedly complex relationship between the best algorithm and the number and size of the tridiagonal systems, which was not evident from the algebraic formulae in the original paper. Even so, for a particular computer, one diagram suffices to predict the best algorithm for all problems that are likely to be encountered the prediction being read directly from the diagram without complex calculation.
VFT PHASE VOLTAGE MEASUREMENT IN THREE-PHASE ENCLOSED GIS
Institute of Scientific and Technical Information of China (English)
邹建华; 岳子丁; 李洋
2002-01-01
The measuring of VFT phase voltage in three-phase enclosed GIS is more complex and difficult than in single-phase ones. There are 3 capacitive sensors in the measuring system, the outputs of which are with a linear relation to the three phase voltages. This linear relation is presented with a factorial matrix. Because each capacitive sensor is coupled with the electric field of three phases (A, B, and C), the electric coupling coefficients are introduced. In order to determine the matrix of electric coupling coefficients, the numerical calculation method can be used. From the discussion on two types of three-phase enclosed GIS bus, i.e. standard arrangement and biased arrangement, the dominant electric coupling coefficients are named, which can be simply and approximately calculated by an analytic expression. Finally, as an example, the waveforms of VFT phase voltage generated on a three-phase enclosed GIS bus model are displayed. When a capacitive sensor is located at the 'shortest point' of phase A (or B, or C), the VFT phase voltage VA (or VB, or VC) can almost be measured by that capacitive sensor alone.
Phase aberration effects in elastography.
Varghese, T; Bilgen, M; Ophir, J
2001-06-01
In sonography, phase aberration plays a role in the corruption of sonograms. Phase aberration does not have a significant impact on elastography, if statistically similar phase errors are present in both the pre- and postcompression signals. However, if the phase errors are present in only one of the pre- or postcompression signal pairs, the precision of the strain estimation process will be reduced. In some cases, increased phase errors may occur only in the postcompression signal due to changes in the tissue structure with the applied compression. Phase-aberration effects increase with applied strain and may be viewed as an image quality derating factor, much like frequency-dependent attenuation or undesired lateral tissue motion. In this paper, we present a theoretical and simulation study of the effects of phase aberration on the elastographic strain-estimation process, using the strain filter approach.
Phase Referencing in Optical Interferometry
Filho, Mercedes E; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie; de Becker, Michael; Surdej, Jean; Aringer, Bernard; Hron, Joseph; Lebzelter, Thomas; Chiavassa, Andrea; Corradi, Romano; Harries, Tim
2008-01-01
One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two extremes of phase corruption by the atmosphere. While in radio it is possible to obtain calibrated phases for the science objects, in the optical this is currently not possible. Instead, optical interferometry has relied on closure phase techniques to produce images. Such techniques allow only to achieve modest dynamic ranges. However, with high contrast objects, for faint targets or when structure detail is needed, phase referencing techniques as used in radio interferometry, should theoretically achieve higher dynamic ranges for the same number of telescopes. Our approach is not to provide evidence either for or against the hypothesis that phase referenced imaging gives better dynamic range than closure phase imaging. Instead we wish to explore the potential of this techniq...
Joint estimation of phase and phase diffusion for quantum metrology
Vidrighin, Mihai D; Genoni, Marco G; Jin, Xian-Min; Kolthammer, W Steven; Kim, M S; Datta, Animesh; Barbieri, Marco; Walmsley, Ian A
2014-01-01
Phase estimation, at the heart of many quantum metrology and communication schemes, can be strongly affected by noise, whose amplitude may not be known, or might be subject to drift. Here, we investigate the joint estimation of a phase shift and the amplitude of phase diffusion, at the quantum limit. For several relevant instances, this multiparameter estimation problem can be effectively reshaped as a two-dimensional Hilbert space model, encompassing the description of an interferometer phase probed with relevant quantum states -- split single-photons, coherent states or N00N states. For these cases, we obtain a trade-off bound on the statistical variances for the joint estimation of phase and phase diffusion, as well as optimum measurement schemes. We use this bound to quantify the effectiveness of an actual experimental setup for joint parameter estimation for polarimetry. We conclude by discussing the form of the trade-off relations for more general states and measurements.
Nonlinear Phase Control and Anomalous Phase Matching in Plasmonic Metasurfaces
Almeida, Euclides; Prior, Yehiam
2015-01-01
Metasurfaces, and in particular those containing plasmonic-based metallic elements, constitute a particularly attractive set of materials. By means of modern nanolithographic fabrication techniques, flat, ultrathin optical elements may be constructed. However, in spite of their strong optical nonlinearities, plasmonic metasurfaces have so far been investigated mostly in the linear regime. Here we introduce full nonlinear phase control over plasmonic elements in metasurfaces. We show that for nonlinear interactions in a phase-gradient nonlinear metasurface a new anomalous nonlinear phase matching condition prevails, which is the nonlinear analog of the generalized Snell law demonstrated for linear metasurfaces. This phase matching condition is very different from the other known phase matching schemes. The subwavelength phase control of optical nonlinearities provides a foundation for the design of flat nonlinear optical elements based on metasurfaces. Our demonstrated flat nonlinear elements (i.e. lenses) act...
About Phase: Synthetic Aperture Radar and the Phase Retrieval
2014-03-01
apply certain ideas from phase retrieval to resolve phase errors in SAR . Specifically, we use bistatic techniques to measure relative phases, and then we...imaging a scene of interest (left) using bistatic SAR techniques at three different times. As in Example 5.5, at the first time instant the aircraft are...Synthetic aperture radar ( SAR ) uses relative motion to produce fine resolution images from microwave frequencies and is a useful tool for regular
Phase computations and phase models for discrete molecular oscillators
2012-01-01
Background Biochemical oscillators perform crucial functions in cells, e.g., they set up circadian clocks. The dynamical behavior of oscillators is best described and analyzed in terms of the scalar quantity, phase. A rigorous and useful definition for phase is based on the so-called isochrons of oscillators. Phase computation techniques for continuous oscillators that are based on isochrons have been used for characterizing the behavior of various types of oscillators under the influence of perturbations such as noise. Results In this article, we extend the applicability of these phase computation methods to biochemical oscillators as discrete molecular systems, upon the information obtained from a continuous-state approximation of such oscillators. In particular, we describe techniques for computing the instantaneous phase of discrete, molecular oscillators for stochastic simulation algorithm generated sample paths. We comment on the accuracies and derive certain measures for assessing the feasibilities of the proposed phase computation methods. Phase computation experiments on the sample paths of well-known biological oscillators validate our analyses. Conclusions The impact of noise that arises from the discrete and random nature of the mechanisms that make up molecular oscillators can be characterized based on the phase computation techniques proposed in this article. The concept of isochrons is the natural choice upon which the phase notion of oscillators can be founded. The isochron-theoretic phase computation methods that we propose can be applied to discrete molecular oscillators of any dimension, provided that the oscillatory behavior observed in discrete-state does not vanish in a continuous-state approximation. Analysis of the full versatility of phase noise phenomena in molecular oscillators will be possible if a proper phase model theory is developed, without resorting to such approximations. PMID:22687330
Quantum Phase Transitions and Dimerized Phases in Frustrated Spin Ladder
Institute of Scientific and Technical Information of China (English)
WEN Rui; LIU Guang-Hua; TIAN Guang-Shan
2011-01-01
In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group (DMRG) algorithm. Effect of the intra-chain next-nearestneighbor (NNN) super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.
Lau, S. S.; Liu, B. X.; Nicolet, M.-A.
1983-05-01
Interactions induced by ion irradiation are generally considered to be non-equilibrium processes, whereas phase diagrams are determined by phase equilibria. These two entities are seemingly unrelated. However, if one assumes that quasi-equilibrium conditions prevail after the prompt events, subsequent reactions are driven toward equilibrium by thermodynamical forces. Under this assumption, ion-induced reactions are related to equilibrium and therefore to phase diagrams. This relationship can be seen in the similarity that exists in thin films between reactions induced by ion irradiation and reactions induced by thermal annealing. In the latter case, phase diagrams have been used to predict the phase sequence of stable compound formation, notably so in cases of silicide formation. Ion-induced mixing not only can lead to stable compound formation, but also to metastable alloy formation. In some metal-metal systems, terminal solubilities can be greatly extended by ion mixing. In other cases, where the two constituents of the system have different crystal structures, extension of terminal solubility from both sides of the phase diagram eventually becomes structurally incompatible and a glassy (amorphous) mixture can form. The composition range where this bifurcation is likely to occur is in the two-phase regions of the phase diagram. These concepts are potentially useful guides in selecting metal pairs that from metallic glasses by ion mixing. In this report, phenomenological correlation between stable (and metastable) phase formation and phase diagram is discussed in terms of recent experimental data.
Carlstrom, Nicholas Mercury
2016-01-01
This position with the Simulation and Graphics Branch (ER7) at Johnson Space Center (JSC) provided an introduction to vehicle hardware, mission planning, and simulation design. ER7 supports engineering analysis and flight crew training by providing high-fidelity, real-time graphical simulations in the Systems Engineering Simulator (SES) lab. The primary project assigned by NASA mentor and SES lab manager, Meghan Daley, was to develop a graphical simulation of the rendezvous, proximity operations, and docking (RPOD) phases of flight. The simulation is to include a generic crew/cargo transportation vehicle and a target object in low-Earth orbit (LEO). Various capsule, winged, and lifting body vehicles as well as historical RPOD methods were evaluated during the project analysis phase. JSC core mission to support the International Space Station (ISS), Commercial Crew Program (CCP), and Human Space Flight (HSF) influenced the project specifications. The simulation is characterized as a 30 meter +V Bar and/or -R Bar approach to the target object's docking station. The ISS was selected as the target object and the international Low Impact Docking System (iLIDS) was selected as the docking mechanism. The location of the target object's docking station corresponds with the RPOD methods identified. The simulation design focuses on Guidance, Navigation, and Control (GNC) system architecture models with station keeping and telemetry data processing capabilities. The optical and inertial sensors, reaction control system thrusters, and the docking mechanism selected were based on CCP vehicle manufacturer's current and proposed technologies. A significant amount of independent study and tutorial completion was required for this project. Multiple primary source materials were accessed using the NASA Technical Report Server (NTRS) and reference textbooks were borrowed from the JSC Main Library and International Space Station Library. The Trick Simulation Environment and User
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-11-01
Knud E. Hansen A/S (KEH) has, partly funded by the Energy Research Programme, (EFP-95) investigated in the possibilities of using windships for transportation of cargo on long routes, i.e. across the Atlantic or Pacific Ocean. The task was to peruse experiences from projects made during the past 30 years and then, based on new materials and design principle to make proposals to modern wind driven ships to transportation of cargo - especially bulk carriers. KEH has thus prepared a suggestion for a 50,000 DWT wind driven bulk carrier on these terms. The bulk carrier in question is a modern rig inspired by the classical lugger and junk sail with a total sail area of abt. 10,000 m{sup 2}. The hull of the ship has been developed in order to limit wave resistance and drifting. Project Windship has, in contrast to earlier tests and projects, designed a bulk carrier based on a complete evaluation of ecology, safety, economy and reasonable transportation speed. The research project shows that international sea transportation, with wind as the primary source of energy, does not seem to run up against any obstacles as regards safety. The economical analyses show that windship transportation, with today`s oil prices, will be about 10% higher compared to the diesel driven transportation. In the light of the positive results of the research project the steering committee recommends that phase II of project `Modern Windships` is carried out. (EG)
Optimal Phase Oscillatory Network
Follmann, Rosangela
2013-03-01
Important topics as preventive detection of epidemics, collective self-organization, information flow and systemic robustness in clusters are typical examples of processes that can be studied in the context of the theory of complex networks. It is an emerging theory in a field, which has recently attracted much interest, involving the synchronization of dynamical systems associated to nodes, or vertices, of the network. Studies have shown that synchronization in oscillatory networks depends not only on the individual dynamics of each element, but also on the combination of the topology of the connections as well as on the properties of the interactions of these elements. Moreover, the response of the network to small damages, caused at strategic points, can enhance the global performance of the whole network. In this presentation we explore an optimal phase oscillatory network altered by an additional term in the coupling function. The application to associative-memory network shows improvement on the correct information retrieval as well as increase of the storage capacity. The inclusion of some small deviations on the nodes, when solutions are attracted to a false state, results in additional enhancement of the performance of the associative-memory network. Supported by FAPESP - Sao Paulo Research Foundation, grant number 2012/12555-4
Phase Transformations and Earthquakes
Green, H. W.
2011-12-01
Phase transformations have been cited as responsible for, or at least involved in, "deep" earthquakes for many decades (although the concept of "deep" has varied). In 1945, PW Bridgman laid out in detail the string of events/conditions that would have to be achieved for a solid/solid transformation to lead to a faulting instability, although he expressed pessimism that the full set of requirements would be simultaneously achieved in nature. Raleigh and Paterson (1965) demonstrated faulting during dehydration of serpentine under stress and suggested dehydration embrittlement as the cause of intermediate depth earthquakes. Griggs and Baker (1969) produced a thermal runaway model of a shear zone under constant stress, culminating in melting, and proposed such a runaway as the origin of deep earthquakes. The discovery of Plate Tectonics in the late 1960s established the conditions (subduction) under which Bridgman's requirements for earthquake runaway in a polymorphic transformation could be possible in nature and Green and Burnley (1989) found that instability during the transformation of metastable olivine to spinel. Recent seismic correlation of intermediate-depth-earthquake hypocenters with predicted conditions of dehydration of antigorite serpentine and discovery of metastable olivine in 4 subduction zones, suggests strongly that dehydration embrittlement and transformation-induced faulting are the underlying mechanisms of intermediate and deep earthquakes, respectively. The results of recent high-speed friction experiments and analysis of natural fault zones suggest that it is likely that similar processes occur commonly during many shallow earthquakes after initiation by frictional failure.
Energy Technology Data Exchange (ETDEWEB)
Vargas-MartInez, J M; Moya-Cessa, H [INAOE, Coordinacion de Optica, Apartado Postal 51 y 216, 72000 Puebla (Mexico)
2004-03-01
Based on the phase operator introduced by Turski we present a formalism for phase that passes Barnett-Pegg's acid test giving the correct phase variance for a number state. We show that this formalism is in fact the radially integrated Q-function formalism that is used to obtain phase properties. It is also shown that depending on the commutation relation used for phase and number, the phase fluctuations for a coherent state obtained from the integrated Q-function tend to the 1/2{rho}{sup 2} limit while for the Pegg-Barnett formalism they tend to 1/(4{rho}{sup 2}+3/{pi}{sup 2}) just like the fluctuations from the integrated Wigner function, where {rho} is the amplitude of the coherent state00.
Piper, Timm; Piper, Jörg
2013-10-01
Using the optical methods described, phase specimens can be observed with a modified light microscope in enhanced clarity, purified from typical artifacts which are apparent in standard phase contrast illumination. In particular, haloing and shade-off are absent, lateral and vertical resolution are maximized and the image quality remains constant even in problematic preparations which cannot be well examined in normal phase contrast, such as specimens beyond a critical thickness or covered by obliquely situated cover slips. The background brightness and thus the range of contrast can be continuously modulated and specimens can be illuminated in concentric-peripheral, axial or paraxial light. Additional contrast effects can be achieved by spectral color separation. Normal glass or mirror lenses can be used; they do not need to be fitted with a phase plate or a phase ring. The methods described should be of general interest for all disciplines using phase microscopy.
Learning phase transitions by confusion
van Nieuwenburg, Evert P L; Huber, Sebastian D
2016-01-01
Classifying phases of matter is a central problem in physics. For quantum mechanical systems, this task can be daunting owing to the exponentially large Hilbert space. Thanks to the available computing power and access to ever larger data sets, classification problems are now routinely solved using machine learning techniques. Here, we propose to use a neural network based approach to find phase transitions depending on the performance of the neural network after training it with deliberately incorrectly labelled data. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to a generic tool to identify unexplored phase transitions.
Machine learning phases of matter
Carrasquilla, Juan; Melko, Roger G.
2016-01-01
Neural networks can be used to identify phases and phase transitions in condensed matter systems via supervised machine learning. Readily programmable through modern software libraries, we show that a standard feed-forward neural network can be trained to detect multiple types of order parameter directly from raw state configurations sampled with Monte Carlo. In addition, they can detect highly non-trivial states such as Coulomb phases, and if modified to a convolutional neural network, topol...
Modulational instability of nematic phase
Indian Academy of Sciences (India)
T Mithun; K Porsezian
2014-02-01
We numerically observe the effect of homogeneous magnetic field on the modulationally stable case of polar phase in = 2 spinor Bose–Einstein condensates (BECs). Also we investigate the modulational instability of uniaxial and biaxial (BN) states of polar phase. Our observations show that the magnetic field triggers the modulational instability and demonstrate that irrespective of the magnetic field effect the uniaxial and biaxial nematic phases show modulational instability.
Phase structures in fuzzy geometries
Govindarajan, T R; Gupta, K S; Martin, X
2012-01-01
We study phase structures of quantum field theories in fuzzy geometries. Several examples of fuzzy geometries as well as QFT's on such geometries are considered. They are fuzzy spheres and beyond as well as noncommutative deformations of BTZ blackholes. Analysis is done analytically and through simulations. Several features like novel stripe phases as well as spontaneous symmetry breaking avoiding Colemen, Mermin, Wagner theorem are brought out. Also we establish that these phases are stable due to topological obstructions.
What Are Clinical Trial Phases?
Full Text Available ... Phases of Clinical Trials Cancer Treatment Types of Cancer Treatment Surgery Radiation Therapy Chemotherapy Immunotherapy Targeted Therapy Hormone Therapy Stem Cell Transplant Precision ...
Phase retrieval with prior information.
Irwan, R; Lane, R G
1998-09-01
An algorithm for phase retrieval with Bayesian statistics is discussed. It is shown how the statistics of Kolmogorov turbulence can be used to compute the likelihood for a particular phase screen. This likelihood is then added to that of the observed data to produce a functional that is maximized directly by use of conjugate gradient maximization. It is shown that although this can significantly improve the quality of the phase estimate,the issue is complicated by local maxima introduced by the possibility of phase wrapping. The causes of the local maxima are analyzed, and a method that increases the likelihood of convergence to the global maximum is presented.
Energy Technology Data Exchange (ETDEWEB)
Klimov, Andrei B [Departamento de FIsica, Universidad de Guadalajara, Revolucion 1500, 44420 Guadalajara, Jalisco (Mexico); Sanchez-Soto, Luis L [Departamento de Optica, Facultad de FIsica, Universidad Complutense, 28040 Madrid (Spain); Guise, Hubert de [Department of Physics, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Bjoerk, Gunnar [Department of Microelectronics and Information Technology, Royal Institute of Technology (KTH), Electrum 229, SE-164 40 Kista (Sweden)
2004-04-02
We consider various approaches to treat the phases of a qutrit. Although it is possible to represent qutrits in a convenient geometrical manner by resorting to a generalization of the Poincare sphere, we argue that the appropriate way of dealing with this problem is through phase operators associated with the algebra su(3). The rather unusual properties of these phases are caused by the small dimension of the system and are explored in detail. We also examine the positive operator-valued measures that can describe the qutrit phase properties.
Magnetic resonance of phase transitions
Owens, Frank J; Farach, Horacio A
1979-01-01
Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also
Phase transitions in operational risk.
Anand, Kartik; Kühn, Reimer
2007-01-01
In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for the dynamical evolution of order parameters are obtained. Under equilibrium conditions, expressions for the stationary states are also obtained. Consequences of the analytical theory developed are analyzed using phase diagrams. We find coexistence of operational and nonoperational phases, much as in liquid-gas systems. Such systems are susceptible to discontinuous phase transitions from the operational to nonoperational phase via catastrophic breakdown. We find this feature to be robust against variation of the microscopic modeling assumptions.
Phase error correction in wavefront curvature sensing via phase retrieval
DEFF Research Database (Denmark)
Almoro, Percival; Hanson, Steen Grüner
2008-01-01
Wavefront curvature sensing with phase error correction system is carried out using phase retrieval based on a partially-developed volume speckle field. Various wavefronts are reconstructed: planar, spherical, cylindrical, and a wavefront passing through the side of a bare optical fiber. Spurious...
Savanna ecosystem project: phase I summary and phase II progress
CSIR Research Space (South Africa)
Huntely, BJ
1978-07-01
Full Text Available A summary of the results of the first phase (mid 1974 to mid 1976) of the South African Savanna Ecosystem Project being undertaken at Nylsvley in the northern Transvaal is presented. Phase I of this ten year study of the structure and functioning...
Condensed phase decomposition and gas phase combustion of hydrazinium nitroformate
Dragomir, O.E.; Tummers, M.J.; Veen, E.H. van; Heijden, A.E.D.M. van der; Roekaerts, D.J.E.M.
2009-01-01
This paper presents the results of a series of experiments on the condensed phase decomposition and the gas phase combustion of hydrazinium nitroformate (HNF). The experiments include SEM analysis of quenched samples that showed evidence of the formation of a foam layer. FTIR spectrometry and mass s
Sleep timing and circadian phase in delayed sleep phase syndrome.
Chang, Anne-Marie; Reid, Kathryn J; Gourineni, Ramadevi; Zee, Phyllis C
2009-08-01
Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder in which the timing of the sleep episode occurs later than desired and is associated with difficulty falling asleep, problems awakening on time (e.g., to meet work or school obligations), and daytime sleepiness. The phase relationship between the timing of sleep and endogenous circadian rhythms is critical to the initiation and maintenance of sleep, and significant alteration leads to impairment of sleep quality and duration. The aim of this retrospective study was to determine the phase relationship between sleep-wake times and physiological markers of circadian timing in clinic patients with DSPS. Objective and subjective measures of sleep timing and circadian phase markers (core body temperature and melatonin) were measured in patients with DSPS and compared with age-matched controls. As expected, significant delays in the timing of the major sleep episode and circadian phase of body temperature and melatonin rhythms were seen in the DSPS group when allowed to sleep at their own habitual schedules, but the phase relationship between sleep-wake times and circadian phase was similar between the 2 groups. These results suggest that the symptoms of insomnia and excessive daytime sleepiness in DSPS patients living under entrained real-life conditions cannot be explained by an alteration in the phase relationship between sleep-wake patterns and other physiological circadian rhythms.
Tanda, Satoshi; Matsuyama, Toyoki; Oda, Migaku; Asano, Yasuhiro; Yakubo, Kousuke
2006-08-01
.]. Nanofibers of hydrogen storage alloy / I. Saita ... [et al.]. Synthesis of stable icosahedral quasicrystals in Zn-Sc based alloys and their magnetic properties / S. Kashimoto and T. Ishimasa. One-armed spiral wave excited by eam pressure in accretion disks in Be/X-Ray binaries / K. Hayasaki and A. T. Okazaki -- IV. Topological defects and excitations. Topological excitations in the ground state of charge density wave systems / P. Monceau. Soliton transport in nanoscale charge-density-wave systems / K. Inagaki, T. Toshima and S. Tanda. Topological defects in triplet superconductors UPt3, Sr[symbol]RuO[symbol], etc. / K. Maki ... [et al.]. Microscopic structure of vortices in type II superconductors / K. Machida ... [et al.]. Microscopic neutron investigation of the Abrikosov state of high-temperature superconductors / J. Mesot. Energy dissipation at nano-scale topological defects of high-Tc superconductors: microwave study / A. Maeda. Pressure induced topological phase transition in the heavy Fermion compound CeAl[symbol] / H. Miyagawa ... [et al.]. Explanation for the unusual orientation of LSCO square vortex lattice in terms of nodal superconductivity / M. Oda. Local electronic states in Bi[symbol]Sr[symbol]CaCu[symbol]O[symbol] / A. Hashimoto ... [et al.] -- V. Topology in quantum phenomena. Topological vortex formation in a Bose-Einstein condensate of alkali-metal atoms / M. Nakahara. Quantum phase transition of [symbol]He confined in nano-porous media / K. Shirahama, K. Yamamoto and Y. Shibayama. A new mean-field theory for Bose-Einstein condensates / T. Kita. Spin current in topological cristals / Y. Asano. Antiferromagnetic defects in non-magnetic hidden order of the heavy-electron system URu[symbol]Si[symbol] / H. Amitsuka, K. Tenya and M. Yokoyama. Magnetic-field dependences of thermodynamic quantities in the vortex state of Type-II superconductors / K. Watanabe, T. Kita and M. Arai. Three-magnon-mediated nuclear spin relaxation in quantum ferrimagnets of topological
Moment Distributions of Phase Type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
2011-01-01
Moment distributions of phase-type and matrix-exponential distributions are shown to remain within their respective classes. We provide a probabilistic phase-type representation for the former case and an alternative representation, with an analytically appealing form, for the latter. First order...
Oscillator With Low Phase Noise
Kleinberg, Leonard L.
1987-01-01
Phase errors cancelled for high frequency stability. Radio-frequency oscillator achieves high stability of frequency through parallel, two-amplifier configuration in which effects cause phase noise tend to cancel each other. Circuit includes two amplifiers with resonating elements, each constitutes part of feedback loop of other. Generate same frequency because each circuit provides other with conditions necessary for oscillation.
78 FR 33911 - Phased Retirement
2013-06-05
... knowledge and expertise with the next generation of Federal leaders via mentoring and role-modeling. Once... making an election of phased retirement, the procedures for electing phased retirement, the requirements... less than the 3-year period ending on the effective date of the employee's election of...
Microgravity Passive Phase Separator
Paragano, Matthew; Indoe, William; Darmetko, Jeffrey
2012-01-01
A new invention disclosure discusses a structure and process for separating gas from liquids in microgravity. The Microgravity Passive Phase Separator consists of two concentric, pleated, woven stainless- steel screens (25-micrometer nominal pore) with an axial inlet, and an annular outlet between both screens (see figure). Water enters at one end of the center screen at high velocity, eventually passing through the inner screen and out through the annular exit. As gas is introduced into the flow stream, the drag force exerted on the bubble pushes it downstream until flow stagnation or until it reaches an equilibrium point between the surface tension holding bubble to the screen and the drag force. Gas bubbles of a given size will form a front that is moved further down the length of the inner screen with increasing velocity. As more bubbles are added, the front location will remain fixed, but additional bubbles will move to the end of the unit, eventually coming to rest in the large cavity between the unit housing and the outer screen (storage area). Owing to the small size of the pores and the hydrophilic nature of the screen material, gas does not pass through the screen and is retained within the unit for emptying during ground processing. If debris is picked up on the screen, the area closest to the inlet will become clogged, so high-velocity flow will persist farther down the length of the center screen, pushing the bubble front further from the inlet of the inner screen. It is desired to keep the velocity high enough so that, for any bubble size, an area of clean screen exists between the bubbles and the debris. The primary benefits of this innovation are the lack of any need for additional power, strip gas, or location for venting the separated gas. As the unit contains no membrane, the transport fluid will not be lost due to evaporation in the process of gas separation. Separation is performed with relatively low pressure drop based on the large surface
Phases of Cannibal Dark Matter
Farina, Marco; Ruderman, Joshua T; Trevisan, Gabriele
2016-01-01
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes ...
Nanoscale phase change memory materials.
Caldwell, Marissa A; Jeyasingh, Rakesh Gnana David; Wong, H-S Philip; Milliron, Delia J
2012-08-01
Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.
Murphy, Andrew; Haestad, Jace; Morgan, Thomas
2015-09-01
We report characteristics of closed classical orbits in an electric field in phase space produced in photoabsorption. Rydberg states of atomic and molecular hydrogen and helium are considered. The core potential used for the hydrogen molecule is an effective one electron one center core potential evaluated at the internuclear equilibrium distance. Poincare surfaces of section in phase space are generated by integrating the equations of motion in semiparabolic coordinates u = (r + z) 1 / 2 and v = (r - z) 1 / 2, and plotting the location in phase space (pv versus v) whenever u = 0, with the electric field in the z direction. Combination orbits produced by Rydberg electron core scattering are studied and the evolution in phase space of these combination orbits due to scattering from one closed orbit into another is investigated. Connections are made to measured laser photoabsorption experiments that excite Rydberg states (20 recurrence spectra. The phase space structures responsible for the spectra are identified.
Quantum processes on phase space
Anastopoulos, C
2003-01-01
Quantum theory predicts probabilities as well as relative phases between different alternatives of the system. A unified description of both probabilities and phases comes through a generalisation of the notion of a density matrix for histories; this object is the decoherence functional of the consistent histories approach. If we take phases as well as probabilities as primitive elements of our theory, we abandon Kolmogorov probability and can describe quantum theory in terms of fundamental commutative observables, without being obstructed by Bell's and related theorems. Generalising the theory of stochastic processes, we develop the description of relative phases and probabilities for paths on the classical phase space. This description provides a theory of quantum processes. We identify a number of basic postulates and study its corresponding properties. We strongly emphasise the notion of conditioning and are able to write ``quantum differential equations'' as analogous to stochastic differential equations...
Phases in the active liquid phase methanol synthesis catalyst
Energy Technology Data Exchange (ETDEWEB)
Sawant, A.V.; Lee, S.; Kulik, C.J.
1988-01-01
An attempt has been made to identify the phases present in the active catalyst for liquid phase methanol synthesis. X-ray powder diffraction was used to identify the phases. Only metallic Cu was detected, while no Cu/sup +/ species was found to be present. A significant amount of ZnCO/sub 3/ was found to be present in catalysts which had been subjected to high partial pressures of CO/sub 2/. This fact has hitherto not been reported in literature. Some speculations about the effect of ZnCO/sub 3/ on the life of the catalyst are made. 21 refs., 6 figs.
Inhomogeneous phase shifting: an algorithm for nonconstant phase displacements
Energy Technology Data Exchange (ETDEWEB)
Tellez-Quinones, Alejandro; Malacara-Doblado, Daniel
2010-11-10
In this work, we have developed a different algorithm than the classical one on phase-shifting interferometry. These algorithms typically use constant or homogeneous phase displacements and they can be quite accurate and insensitive to detuning, taking appropriate weight factors in the formula to recover the wrapped phase. However, these algorithms have not been considered with variable or inhomogeneous displacements. We have generalized these formulas and obtained some expressions for an implementation with variable displacements and ways to get partially insensitive algorithms with respect to these arbitrary error shifts.
Phase appearance or disappearance in two-phase flows
Cordier, Floraine; Kumbaro, Anela
2011-01-01
This paper is devoted to the treatment of specific numerical problems which appear when phase appearance or disappearance occurs in models of two-phase flows. Such models have crucial importance in many industrial areas such as nuclear power plant safety studies. In this paper, two outstanding problems are identified: first, the loss of hyperbolicity of the system when a phase appears or disappears and second, the lack of positivity of standard shock capturing schemes such as the Roe scheme. After an asymptotic study of the model, this paper proposes accurate and robust numerical methods adapted to the simulation of phase appearance or disappearance. Polynomial solvers are developed to avoid the use of eigenvectors which are needed in usual shock capturing schemes, and a method based on an adaptive numerical diffusion is designed to treat the positivity problems. An alternate method, based on the use of the hyperbolic tangent function instead of a polynomial, is also considered. Numerical results are presente...
Phase shift estimation in interferograms with unknown phase step
Dalmau, Oscar; Rivera, Mariano; Gonzalez, Adonai
2016-08-01
We first present two closed formulas for computing the phase shift in interferograms with unknown phase step. These formulas obtain theoretically the exact phase step in fringe pattern without noise and only require the information in two pixels of the image. The previous formulas allows us to define a functional that yields an estimate of the phase step in interferograms corrupted by noise. In the experiment we use the standard Least Square formulation which also yields a closed formula, although the general formulation admits a robust potential. We provide two possible implementations of our approach, one in which the sites can be randomly selected and the other in which we can scan the whole image. The experiments show that the proposed algorithm presents the best results compared with state of the art algorithms.
Phase Noise in Photonic Phased-Array Antenna Systems
Logan, Ronald T., Jr.; Maleki, Lute
1998-01-01
The total noise of a phased-array antenna system employing a photonic feed network is analyzed using a model for the individual component noise including both additive and multiplicative equivalent noise generators.
Measurement of Phase Dependent Impedance for 3-phase Diode Rectifier
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth
2016-01-01
This paper presents a new method to measure the phase dependent impedance from an experimental set up. Though most of power electronics based system is gradually migrating to IGBT based voltage source converter due to their controllability, the rectifier composed of diode or thyristor components...... are still widely used in AC-DC applications because of their cost effectiveness and reliability. However, these topologies generate harmonic problems in their network due to their switching instant variation caused by the frequency and phase of grid voltage. Hence, a lot of solutions have been proposed...... application. It is found that the phase dependent impedance shows different properties with the impedance profiles, which have been proposed in the research. This paper explains a method to measure the phase dependent impedance profile from an experimental set up. Furthermore, the results are compared...
Phase Behavior and Implications for Travel time Observables (PHASE 2)
2015-09-30
Phase behavior and implications for travel - time observables (PHASE-2) Emmanuel Skarsoulis Foundation for Research and Technology Hellas...perturbation behavior of travel time observables due to sound-speed perturbations. OBJECTIVES The objective is to study the behavior of the wave-theoretic...for this work came from the results of previous studies, supported by ONR, suggesting that the perturbation behavior of different travel - time
An absorbing phase transition from a structured active particle phase
Energy Technology Data Exchange (ETDEWEB)
Lopez, Cristobal [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain); Ramos, Francisco [Departamento de Electromagnetismo y Fisica de la Materia and Instituto de Fisica Teorica y Computacional Carlos I, Facultad de Ciencias, Universidad de Granada, 18071 Granada (Spain); Hernandez-GarcIa, Emilio [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain)
2007-02-14
In this work we study the absorbing state phase transition of a recently introduced model for interacting particles with neighbourhood-dependent reproduction rates. The novelty of the transition is that as soon as the active phase is reached by increasing a control parameter a periodically arranged structure of particle clusters appears. A numerical study in one and two dimensions shows that the system falls into the directed percolation universality class.
SLEEP TIMING AND CIRCADIAN PHASE IN DELAYED SLEEP PHASE
2009-01-01
Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder in which the timing of the sleep episode occurs later than desired and is associated with difficulty falling asleep, problems awakening on time (e.g., to meet work or school obligations), and daytime sleepiness. The phase relationship between the timing of sleep and endogenous circadian rhythms is critical to the initiation and maintenance of sleep, and significant alteration leads to impairment of sleep quality and dura...
Phase Noise Tolerant QPSK Receiver Using Phase Sensitive Wavelength Conversion
DEFF Research Database (Denmark)
Da Ros, Francesco; Xu, Jing; Lei, Lei
2013-01-01
A novel QPSK receiver based on a phase noise reduction pre-stage exploiting PSA in a HNLF and balanced detection is presented. Receiver sensitivity improvement over a conventional balanced receiver is demonstrated.......A novel QPSK receiver based on a phase noise reduction pre-stage exploiting PSA in a HNLF and balanced detection is presented. Receiver sensitivity improvement over a conventional balanced receiver is demonstrated....
Fundamentals of ultrasonic phased arrays
Schmerr, Lester W
2014-01-01
This book describes in detail the physical and mathematical foundations of ultrasonic phased array measurements.?The book uses linear systems theory to develop a comprehensive model of the signals and images that can be formed with phased arrays. Engineers working in the field of ultrasonic nondestructive evaluation (NDE) will find in this approach a wealth of information on how to design, optimize and interpret ultrasonic inspections with phased arrays. The fundamentals and models described in the book will also be of significant interest to other fields, including the medical ultrasound and
Mixed Frequency Ultrasound Phased Array
Institute of Scientific and Technical Information of China (English)
香勇; 霍健; 施克仁; 陈以方
2004-01-01
A mixed frequency ultrasonic phased array (MPA) was developed to improve the focus, in which the element excitation frequencies are not all the same as in a normal constant frequency phased array. A theoretical model of the mixed frequency phased array based on the interference principle was used to simulate the array's sound distribution. The pressure intensity in the array focal area was enhanced and the scanning area having effective contrast resolution was enlarged. The system is especially useful for high intensity focused ultrasound (HIFU) with more powerful energy and ultrasound imaging diagnostics with improved signal to noise ratios, improved beam forming and more uniform imaging quality.
SNMR pulse sequence phase cycling
Walsh, David O; Grunewald, Elliot D
2013-11-12
Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.
Geometrical Phases in Quantum Mechanics
Christian, Joy Julius
In quantum mechanics, the path-dependent geometrical phase associated with a physical system, over and above the familiar dynamical phase, was initially discovered in the context of adiabatically changing environments. Subsequently, Aharonov and Anandan liberated this phase from the original formulation of Berry, which used Hamiltonians, dependent on curves in a classical parameter space, to represent the cyclic variations of the environments. Their purely quantum mechanical treatment, independent of Hamiltonians, instead used the non-trivial topological structure of the projective space of one-dimensional subspaces of an appropriate Hilbert space. The geometrical phase, in their treatment, results from a parallel transport of the time-dependent pure quantum states along a curve in this space, which is endowed with an abelian connection. Unlike Berry, they were able to achieve this without resort to an adiabatic approximation or to a time-independent eigenvalue equation. Prima facie, these two approaches are conceptually quite different. After a review of both approaches, an exposition bridging this apparent conceptual gap is given; by rigorously analyzing a model composite system, it is shown that, in an appropriate correspondence limit, the Berry phase can be recovered as a special case from the Aharonov-Anandan phase. Moreover, the model composite system is used to show that Berry's correction to the traditional Born-Oppenheimer energy spectra indeed brings the spectra closer to the exact results. Then, an experimental arrangement to measure geometrical phases associated with cyclic and non-cyclic variations of quantum states of an entangled composite system is proposed, utilizing the fundamental ideas of the recently opened field of two-particle interferometry. This arrangement not only resolves the controversy regarding the true nature of the phases associated with photon states, but also unequivocally predicts experimentally accessible geometrical phases in a
Quantum mechanics in phase space
DEFF Research Database (Denmark)
Hansen, Frank
1984-01-01
A reformulation of quantum mechanics for a finite system is given using twisted multiplication of functions on phase space and Tomita's theory of generalized Hilbert algebras. Quantization of a classical observable h is achieved when the twisted exponential Exp0(-h) is defined as a tempered....... Generalized Weyl-Wigner maps related to the notion of Hamiltonian weight are studied and used in the formulation of a twisted spectral theory for functions on phase space. Some inequalities for Wigner functions on phase space are proven. A brief discussion of the classical limit obtained through dilations...
Review: Acute phase reaction and acute phase proteins
Institute of Scientific and Technical Information of China (English)
GRUYS E.; TOUSSAINT M.J.M.; NIEWOLD T.A.; KOOPMANS S.J.
2005-01-01
A review of the systemic acute phase reaction with major cytokines involved, and the hepatic metabolic changes,negative and positive acute phase proteins (APPs) with function and associated pathology is given. It appears that APPs represent appropriate analytes for assessment of animal health. Whereas they represent non-specific markers as biological effect reactants,they can be used for assessing nutritional deficits and reactive processes, especially when positive and negative acute phase variables are combined in an index. When such acute phase index is applied to separate healthy animals from animals with some disease, much better results are obtained than with single analytes and statistically acceptable results for culling individual animals may be reached.Unfortunately at present no cheap, comprehensive and easy to use system is available for assessing various acute phase proteins in serum or blood samples at the same time. Protein microarray or fluid phase microchip technology may satisfy this need;and permit simultaneous analysis of numerous analytes in the same small volume sample and enable integration of information derived from systemic reactivity and nutrition with disease specific variables. Applying such technology may help to solve health problems in various countries not only in animal husbandry but also in human populations.
Phase diagrams and kinetics of phase transitions in protein solutions.
Vekilov, Peter G
2012-05-16
The phase behavior of proteins is of interest for fundamental and practical reasons. The nucleation of new phases is one of the last major unresolved problems of nature. The formation of protein condensed phases (crystals, polymers, and other solid aggregates, as well as dense liquids and gels) underlies pathological conditions, plays a crucial role in the biological function of the respective protein, or is an essential part of laboratory and industrial processes. In this review, we focus on phase transitions of proteins in their properly folded state. We first summarize the recently acquired understanding of physical processes underlying the phase diagrams of the protein solutions and the thermodynamics of protein phase transitions. Then we review recent findings on the kinetics of nucleation of dense liquid droplets and crystals. We explore the transition from nucleation to spinodal decomposition for liquid-liquid separation and introduce the new concept of solution-to-crystal spinodal. We review the two-step mechanism of protein crystal nucleation, in which mesoscopic metastable protein clusters serve as precursors to the ordered crystal nuclei. The concepts and mechanisms reviewed here provide powerful tools for control of the nucleation process by varying the solution thermodynamic parameters.
Rivera, Mariano; Bizuet, Rocky; Martinez, Amalia; Rayas, Juan A
2006-04-17
We present a phase shifting robust method for irregular and unknown phase steps. The method is formulated as the minimization of a half-quadratic (robust) regularized cost function for simultaneously computing phase maps and arbitrary phase shifts. The convergence to, at least, a local minimum is guaranteed. The algorithm can be understood as a phase refinement strategy that uses as initial guess a coarsely computed phase and coarsely estimated phase shifts. Such a coarse phase is assumed to be corrupted with artifacts produced by the use of a phase shifting algorithm but with imprecise phase steps. The refinement is achieved by iterating alternated minimization of the cost function for computing the phase map correction, an outliers rejection map and the phase shifts correction, respectively. The method performance is demonstrated by comparison with standard filtering and arbitrary phase steps detecting algorithms.
CLIC Drive Beam Phase Stabilisation
Gerbershagen, Alexander; Schulte, Daniel
The thesis presents phase stability studies for the Compact Linear Collider (CLIC) and focuses in particular on CLIC Drive Beam longitudinal phase stabilisation. This topic constitutes one of the main feasibility challenges for CLIC construction and is an essential component of the current CLIC stabilisation campaign. The studies are divided into two large interrelated sections: the simulation studies for the CLIC Drive Beam stability, and measurements, data analysis and simulations of the CLIC Test Facility (CTF3) Drive Beam phase errors. A dedicated software tool has been developed for a step-by-step analysis of the error propagation through the CLIC Drive Beam. It uses realistic RF potential and beam loading amplitude functions for the Drive and Main Beam accelerating structures, complete models of the recombination scheme and compressor chicane as well as of further CLIC Drive Beam modules. The tool has been tested extensively and its functionality has been verified. The phase error propagation at CLIC h...
Multiobjective Optimization and Phase Transitions
Seoane, Luís F
2015-01-01
Many complex systems obey to optimality conditions that are usually not simple. Conflicting traits often interact making a Multi Objective Optimization (MOO) approach necessary. Recent MOO research on complex systems report about the Pareto front (optimal designs implementing the best trade-off) in a qualitative manner. Meanwhile, research on traditional Simple Objective Optimization (SOO) often finds phase transitions and critical points. We summarize a robust framework that accounts for phase transitions located through SOO techniques and indicates what MOO features resolutely lead to phase transitions. These appear determined by the shape of the Pareto front, which at the same time is deeply related to the thermodynamic Gibbs surface. Indeed, thermodynamics can be written as an MOO from where its phase transitions can be parsimoniously derived; suggesting that the similarities between transitions in MOO-SOO and Statistical Mechanics go beyond mere coincidence.
Energy Technology Data Exchange (ETDEWEB)
Weston, R.E. Jr.; Sears, T.J.; Preses, J.M. [Brookhaven National Laboratory, Upton, NY (United States)
1993-12-01
Research in this program is directed towards the spectroscopy of small free radicals and reactive molecules and the state-to-state dynamics of gas phase collision, energy transfer, and photodissociation phenomena. Work on several systems is summarized here.
Berry phase in Heisenberg representation
Andreev, V. A.; Klimov, Andrei B.; Lerner, Peter B.
1994-01-01
We define the Berry phase for the Heisenberg operators. This definition is motivated by the calculation of the phase shifts by different techniques. These techniques are: the solution of the Heisenberg equations of motion, the solution of the Schrodinger equation in coherent-state representation, and the direct computation of the evolution operator. Our definition of the Berry phase in the Heisenberg representation is consistent with the underlying supersymmetry of the model in the following sense. The structural blocks of the Hamiltonians of supersymmetrical quantum mechanics ('superpairs') are connected by transformations which conserve the similarity in structure of the energy levels of superpairs. These transformations include transformation of phase of the creation-annihilation operators, which are generated by adiabatic cyclic evolution of the parameters of the system.
Non-equilibrium phase transitions
Henkel, Malte; Lübeck, Sven
2009-01-01
This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.
Numerical methods for phase retrieval
Osherovich, Eliyahu
2012-01-01
In this work we consider the problem of reconstruction of a signal from the magnitude of its Fourier transform, also known as phase retrieval. The problem arises in many areas of astronomy, crystallography, optics, and coherent diffraction imaging (CDI). Our main goal is to develop an efficient reconstruction method based on continuous optimization techniques. Unlike current reconstruction methods, which are based on alternating projections, our approach leads to a much faster and more robust method. However, all previous attempts to employ continuous optimization methods, such as Newton-type algorithms, to the phase retrieval problem failed. In this work we provide an explanation for this failure, and based on this explanation we devise a sufficient condition that allows development of new reconstruction methods---approximately known Fourier phase. We demonstrate that a rough (up to $\\pi/2$ radians) Fourier phase estimate practically guarantees successful reconstruction by any reasonable method. We also pres...
Phase retrieval in protein crystallography.
Liu, Zhong Chuan; Xu, Rui; Dong, Yu Hui
2012-03-01
Solution of the phase problem is central to crystallographic structure determination. An oversampling method is proposed, based on the hybrid input-output algorithm (HIO) [Fienup (1982). Appl. Opt. 21, 2758-2769], to retrieve the phases of reflections in crystallography. This method can extend low-resolution structures to higher resolution for structure determination of proteins without additional sample preparation. The method requires an envelope of the protein which divides a unit cell into the density region where the proteins are located and the non-density region occupied by solvents. After a few hundred to a few thousand iterations, the correct phases and density maps are recovered. The method has been used successfully in several cases to retrieve the phases from the experimental X-ray diffraction data and the envelopes of proteins constructed from structure files downloaded from the Protein Data Bank. It is hoped that this method will greatly facilitate the ab initio structure determination of proteins.
Solid-Phase Random Glycosylation
DEFF Research Database (Denmark)
Agoston, K.; Kröger, Lars; Dekany, Gyula
2009-01-01
Two different approaches were employed to study solid phase random glycosylations to obtain oligosaccharide libraries. In approach I, Wang resin esters were attached to the acceptors structures. Following their glycosylation and resin cleavage, the peracetylated components of the oligosaccharide ...
APPARATUS FOR LIQUID PHASE EXTRACTION
Hicks, T.R.; Lehman, H.R.; Rubin, B.
1958-09-16
operation is described. It comprises a tubular colunm having upper and lower enlarged terminal portions, and a constricted central section containing fluid dispersal packing. Pulsing means are coupled to the upper portion of the column. The inlet for the less dense phase is located above the inlet for the denser phase and both are positioned so that liquids enter the constricted packingfilled central section. The apparatos also includes an interfacing level control, and means fer sensing the level of the interface actuate apparatus for controlling the rate of flow of input or discharge. The outlet for the less dense phase is located in the upper packing free portion of the colunm and that of the denser phase in the lower portion.
Berry's Phase in Noncommutative Spaces
Institute of Scientific and Technical Information of China (English)
S. A. Alavi
2003-01-01
We discuss the perturbative aspects of noncommutative quantum mechanics. Then we study Berry's phase within the framework of noncommutative quantum mechanics. The results show deviations from the usual quantum mechanics, which depend on the parameter of space/space noncommutativity.
Precipitation of Icosahedral Quasicrystalline Phase, R-phase and Laves Phase in Ferritic Alloys
Institute of Scientific and Technical Information of China (English)
Keisuke Yamamoto; Yoshisato Kimura; Yoshinao Mishima
2004-01-01
Ferritic heat resistant steels involving precipitation of intermetallic phases have drawn a growing interest for the enhancement of creep strength, while the brittleness of the intermetallic phases may lower the toughness of the alloy.Therefore, it is necessary to optimize the dispersion characteristics of the intermetallics phase through microstructural control to minimize the trade-off between the strength and toughness. The effects of α-Fe matrix substructures on the precipitation sequence, morphology, dispersion characteristics, and the stability of the intermetallic phases are investigated in Fe-Cr-W-Co-Si system. The precipitates of the Si-free Fe-10Cr-1.4W-4.5Co (at%) alloy aged at 873K are the R-phase but those of the Si-added Fe-10Cr-1.4W-4.5Co-0.3Si (at%) alloy are the icosahedral quasicrystalline phase. The precipitates in both the Si-free and Si-added alloys aged at 973K are the Laves phase. Matrix of the alloys is controlled by heat treatments as to provide three types of matrix substructures; ferrite, ferrite/martensite mixture and martensite. The hardening behavior of the alloys depends on the matrix substructures and is independent of the kinds of precipitates. In the alloys with ferrite matrix, the peak of hardness during aging at 873K shifts to longer aging time in comparison with that in the alloys with lath martensite matrix which contain numbers of nucleation sites.
Safety performance of traffic phases and phase transitions in three phase traffic theory.
Xu, Chengcheng; Liu, Pan; Wang, Wei; Li, Zhibin
2015-12-01
Crash risk prediction models were developed to link safety to various phases and phase transitions defined by the three phase traffic theory. Results of the Bayesian conditional logit analysis showed that different traffic states differed distinctly with respect to safety performance. The random-parameter logit approach was utilized to account for the heterogeneity caused by unobserved factors. The Bayesian inference approach based on the Markov Chain Monte Carlo (MCMC) method was used for the estimation of the random-parameter logit model. The proposed approach increased the prediction performance of the crash risk models as compared with the conventional logit model. The three phase traffic theory can help us better understand the mechanism of crash occurrences in various traffic states. The contributing factors to crash likelihood can be well explained by the mechanism of phase transitions. We further discovered that the free flow state can be divided into two sub-phases on the basis of safety performance, including a true free flow state in which the interactions between vehicles are minor, and a platooned traffic state in which bunched vehicles travel in successions. The results of this study suggest that a safety perspective can be added to the three phase traffic theory. The results also suggest that the heterogeneity between different traffic states should be considered when estimating the risks of crash occurrences on freeways.
Geometric phases in graphitic cones
Energy Technology Data Exchange (ETDEWEB)
Furtado, Claudio [Departamento de Fisica, CCEN, Universidade Federal da Paraiba, Cidade Universitaria, 58051-970 Joao Pessoa, PB (Brazil)], E-mail: furtado@fisica.ufpb.br; Moraes, Fernando [Departamento de Fisica, CCEN, Universidade Federal da Paraiba, Cidade Universitaria, 58051-970 Joao Pessoa, PB (Brazil); Carvalho, A.M. de M [Departamento de Fisica, Universidade Estadual de Feira de Santana, BR116-Norte, Km 3, 44031-460 Feira de Santana, BA (Brazil)
2008-08-04
In this Letter we use a geometric approach to study geometric phases in graphitic cones. The spinor that describes the low energy states near the Fermi energy acquires a phase when transported around the apex of the cone, as found by a holonomy transformation. This topological result can be viewed as an analogue of the Aharonov-Bohm effect. The topological analysis is extended to a system with n cones, whose resulting configuration is described by an effective defect00.
Transit time MESFET phase shifter
Walters, Peter C.; Roger D. Pollard; Richardson, John R.
1992-01-01
The phase shift of a signal through a common-source MESFET can be changed with little effect on the amplitude by altering the gate-drain spacing. The feasibility of employing this principle to realize a highly compact, monolithic phase shifter has been investigated. The behaviour of the devices with differing gate-drain spacing has been measured and modelled and a design for a monolithic implementation is presented.
Gait phase varies over velocities.
Liu, Yancheng; Lu, Kun; Yan, Songhua; Sun, Ming; Lester, D Kevin; Zhang, Kuan
2014-02-01
We sought to characterize the percent (PT) of the phases of a gait cycle (GC) as velocity changes to establish norms for pathological gait characteristics with higher resolution technology. Ninety five healthy subjects (49 males and 46 females with age 34.9 ± 11.8 yrs, body weight 64.0 ± 11.7 kg and BMI 23.5 ± 3.6) were enrolled and walked comfortably on a 10-m walkway at self-selected slower, normal, and faster velocities. Walking was recorded with a high speed camera (250 frames per second) and the eight phases of a GC were determined by examination of individual frames for each subject. The correlation coefficients between the mean PT of the phases of the three velocities gaits and PT defined by previous publications were all greater than 0.99. The correlation coefficient between velocity and PT of gait phases is -0.83 for loading response (LR), -0.75 for mid stance (MSt), and -0.84 for pre-swing (PSw). While the PT of the phases of three velocities from this study are highly correlated with PT described by Dr. Jacquenlin Perry decades ago, actual PT of each phase varied amongst these individuals with the largest coefficient variation of 24.31% for IC with slower velocity. From slower to faster walk, the mean PT of MSt diminished from 35.30% to 25.33%. High resolution recording revealed ambiguity of some gait phase definitions, and these data may benefit GC characterization of normal and pathological gait in clinical practice. The study results indicate that one should consider individual variations and walking velocity when evaluating gaits of subjects using standard gait phase classification.
Mindset theory of action phases
Gollwitzer, Peter
2012-01-01
Mindset theory of action phases is based on the distinction between motivation and volition as proposed by the Rubicon model which claims that prior to crossing the Rubicon (i.e., making a goal decision) motivational principles apply whereas thereafter volitional principles set in. The latter are concerned with goal implementation, whereas the former relate to the choosing of goals. Mindset theory of action phases proposes that different cognitive procedures are activated when people tackle t...
Yamamoto, Arata
2016-01-01
We propose the lattice QCD calculation of the Berry phase which is defined by the ground state of a single fermion. We perform the ground-state projection of a single-fermion propagator, construct the Berry link variable on a momentum-space lattice, and calculate the Berry phase. As the first application, the first Chern number of the (2+1)-dimensional Wilson fermion is calculated by the Monte Carlo simulation.
Electroweak phase transition in technicolor
Jarvinen, Matti
2010-01-01
Several phenomenologically viable walking technicolor models have been proposed recently. I demonstrate that these models can have first order electroweak phase transitions, which are sufficiently strong for electroweak baryogenesis. Strong dynamics can also lead to several separate transitions at the electroweak scale, with the possibility of a temporary restoration and an extra breaking of the electroweak symmetry. First order phase transitions will produce gravitational waves, which may be detectable at future experiments.
Phase difference of arrival geolocation
Energy Technology Data Exchange (ETDEWEB)
Mason, John J.; Romero, Louis (
2017-05-16
Geolocation is performed by receiving, at a plurality of non-earthbound platforms each moving in a known manner within a spatial coordinate system, a radio frequency (RF) signal transmitted from a transmitter at an unknown location on earth within the spatial coordinate system. For each of the platforms, a phase change of the received frequency carrier is measured over the same duration of time. The measured phase changes are combined to determine the transmitter location.
Phase Diagrams of Nuclear Pasta
Caplan, Matthew; Horowitz, Chuck; Berry, Don; da Silva Schneider, Andre
2016-03-01
In the inner crust of neutrons stars, where matter is near the saturation density, protons and neutrons arrange themselves into complex structures called nuclear pasta. Early theoretical work predicted a simple graduated hierarchy of pasta phases, consisting of spheres, cylinders, slabs, and uniform matter with voids. Previous work has simulated these phases with a simple classical model and has shown that the formation of these structures is dependent on the temperature, density, and proton fraction. However, previous work only studied a limited range of these parameters due to computational limitations. Thanks to recent advances in computing it is now possible to survey the structure of nuclear pasta for a larger range of parameters. By simulating nuclear pasta with constant temperature and proton fraction in an expanding simulation volume we are able to study the phase transitions in nuclear pasta, and thus produce a set of phase diagrams. We report on these phase diagrams as well as newly identified phases of nuclear pasta and discuss their implications for neutron star observables.
Phase retrieval from speckle images.
Rondeau, Xavier; Thiébaut, Eric; Tallon, Michel; Foy, Renaud
2007-10-01
In ground-based astronomy, the inverse problem of phase retrieval from speckle images is a means to calibrate static aberrations for correction by active optics. It can also be used to sense turbulent wavefronts. However, the number of local minima drastically increases with the turbulence strength, mainly because of phase wrapping ambiguities. Multifocal phase diversity has been considered to overcome some ambiguities of the phase retrieval problem. We propose an effective algorithm for phase retrieval from a single focused image. Our algorithm makes use of a global optimization strategy and an automatically tuned smoothness prior to overcome local minima and phase degeneracies. We push the limit of D/r(0)=4 achieved by Irwan and Lane [J. Opt. Soc. Am. A.15, 2302 (1998)] up to D/r(0)=11, which is a major improvement owing to the drastic increase in the problem complexity. We estimate the performances of our approach from consistent simulations for different turbulence strengths and noise levels (down to 1500 photons per image). We also investigate the benefit of temporal correlation.
Learning phase transitions by confusion
van Nieuwenburg, Evert P. L.; Liu, Ye-Hua; Huber, Sebastian D.
2017-02-01
Classifying phases of matter is key to our understanding of many problems in physics. For quantum-mechanical systems in particular, the task can be daunting due to the exponentially large Hilbert space. With modern computing power and access to ever-larger data sets, classification problems are now routinely solved using machine-learning techniques. Here, we propose a neural-network approach to finding phase transitions, based on the performance of a neural network after it is trained with data that are deliberately labelled incorrectly. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to the development of a generic tool for identifying unexplored phase transitions.
Stochastic phase-change neurons
Tuma, Tomas; Pantazi, Angeliki; Le Gallo, Manuel; Sebastian, Abu; Eleftheriou, Evangelos
2016-08-01
Artificial neuromorphic systems based on populations of spiking neurons are an indispensable tool in understanding the human brain and in constructing neuromimetic computational systems. To reach areal and power efficiencies comparable to those seen in biological systems, electroionics-based and phase-change-based memristive devices have been explored as nanoscale counterparts of synapses. However, progress on scalable realizations of neurons has so far been limited. Here, we show that chalcogenide-based phase-change materials can be used to create an artificial neuron in which the membrane potential is represented by the phase configuration of the nanoscale phase-change device. By exploiting the physics of reversible amorphous-to-crystal phase transitions, we show that the temporal integration of postsynaptic potentials can be achieved on a nanosecond timescale. Moreover, we show that this is inherently stochastic because of the melt-quench-induced reconfiguration of the atomic structure occurring when the neuron is reset. We demonstrate the use of these phase-change neurons, and their populations, in the detection of temporal correlations in parallel data streams and in sub-Nyquist representation of high-bandwidth signals.
Observing SU(2) phases with neutrons
Indian Academy of Sciences (India)
Veer Chand Rakhecha; Apoorva G Wagh
2001-02-01
We present an overview of polarized neutron experiments observing SU(2) phases. The ﬁrst experimental separation of geometric and dynamical phases, the explicit veriﬁcation of Pauli anticommutation and the ﬁrst observation of interference amplitudes and phases in noncyclic evolutions are described. These experiments elucidate the physics of phases and phase jumps propounded by the Pancharatnam connection.
Monodomain Blue Phase Liquid Crystal Layers for Phase Modulation
Oton, E.; Netter, E.; Nakano, T.; D.-Katayama, Y.; Inoue, F.
2017-03-01
Liquid crystal “Blue Phases” (BP) have evolved, in the last years, from a scientific curiosity to emerging materials for new photonic and display applications. They possess attractive features over standard nematic liquid crystals, like submillisecond switching times and polarization- independent optical response. However, BPs still present a number of technical issues that prevent their use in practical applications: their phases are only found in limited temperature ranges, thus requiring stabilization of the layers; stabilized BP layers are inhomogeneous and not uniformly oriented, which worsen the optical performance of the devices. It would be essential for practical uses to obtain perfectly aligned and oriented monodomain BP layers, where the alignment and orientation of the cubic lattice are organized in a single 3D structure. In this work we have obtained virtually perfect monodomain BP layers and used them in devices for polarization independent phase modulation. We demonstrate that, under applied voltage, well aligned and oriented layers generate smoother and higher values of the phase shift than inhomogeneous layers, while preserving polarization independency. All BP devices were successfully stabilized in BPI phase, maintaining the layer monodomain homogeneity at room temperature, covering the entire area of the devices with a unique BP phase.
Monodomain Blue Phase Liquid Crystal Layers for Phase Modulation
Oton, E.; Netter, E.; Nakano, T.; D.-Katayama, Y.; Inoue, F.
2017-01-01
Liquid crystal “Blue Phases” (BP) have evolved, in the last years, from a scientific curiosity to emerging materials for new photonic and display applications. They possess attractive features over standard nematic liquid crystals, like submillisecond switching times and polarization- independent optical response. However, BPs still present a number of technical issues that prevent their use in practical applications: their phases are only found in limited temperature ranges, thus requiring stabilization of the layers; stabilized BP layers are inhomogeneous and not uniformly oriented, which worsen the optical performance of the devices. It would be essential for practical uses to obtain perfectly aligned and oriented monodomain BP layers, where the alignment and orientation of the cubic lattice are organized in a single 3D structure. In this work we have obtained virtually perfect monodomain BP layers and used them in devices for polarization independent phase modulation. We demonstrate that, under applied voltage, well aligned and oriented layers generate smoother and higher values of the phase shift than inhomogeneous layers, while preserving polarization independency. All BP devices were successfully stabilized in BPI phase, maintaining the layer monodomain homogeneity at room temperature, covering the entire area of the devices with a unique BP phase. PMID:28281691
Long Term Sunspot Cycle Phase Coherence with Periodic Phase Disruptions
Pease, Gerald E
2016-01-01
In 1965 Paul D. Jose published his discovery that both the motion of the Sun about the center of mass of the solar system and periods comprised of eight Hale magnetic sunspot cycles with a mean period of ~22.375 years have a matching periodicity of ~179 years. We have investigated the implied link between solar barycentric torque cycles and sunspot cycles and have found that the unsigned solar torque values from 1610 to 2058 are consistently phase and magnitude coherent in ~179 year Jose Cycles. We are able to show that there is also a surprisingly high degree of sunspot cycle phase coherence for times of minima in addition to magnitude correlation of peaks between the nine Schwabe sunspot cycles of 1878 through 1976 (SC12 through SC20) and those of 1699 through 1797 (SC[-5] through SC4). We further identify subsequent subcycles of predominantly non-coherent sunspot cycle phase. In addition we have analyzed the empirical solar motion triggers of both sunspot cycle phase coherence and phase coherence disruptio...
Phases and phase transitions in the algebraic microscopic shell model
Directory of Open Access Journals (Sweden)
Georgieva A. I.
2016-01-01
Full Text Available We explore the dynamical symmetries of the shell model number conserving algebra, which define three types of pairing and quadrupole phases, with the aim to obtain the prevailing phase or phase transition for the real nuclear systems in a single shell. This is achieved by establishing a correspondence between each of the pairing bases with the Elliott’s SU(3 basis that describes collective rotation of nuclear systems. This allows for a complete classification of the basis states of different number of particles in all the limiting cases. The probability distribution of the SU(3 basis states within theirs corresponding pairing states is also obtained. The relative strengths of dynamically symmetric quadrupole-quadrupole interaction in respect to the isoscalar, isovector and total pairing interactions define a control parameter, which estimates the importance of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.
Phase-Locked Loop Noise Reduction via Phase Detector Implementation for Single-Phase Systems
Energy Technology Data Exchange (ETDEWEB)
Thacker, Timothy [Virginia Polytechnic Institute and State University (Virginia Tech); Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech); Burgos, Rolando [ABB; Wang, Fei [ORNL
2011-01-01
A crucial component of grid-connected converters is the phase-locked loop (PLL) control subsystem that tracks the grid voltage's frequency and phase angle. Therefore, accurate fast-responding PLLs for control and protection purposes are required to provide these measurements. This paper proposes a novel feedback mechanism for single-phase PLL phase detectors using the estimated phase angle. Ripple noise appearing in the estimated frequency, most commonly the second harmonic under phase-lock conditions, is reduced or eliminated without the use of low-pass filters, which can cause delays to occur and limits the overall performance of the PLL response to dynamic changes in the system. The proposed method has the capability to eliminate the noise ripple entirely and, under extreme line distortion conditions, can reduce the ripple by at least half. Other modifications implemented through frequency feedback are shown to decrease the settling time of the PLL up to 50%. Mathematical analyses with the simulated and experimental results are provided to confirm the validity of the proposed methods.
Dynamic Modeling of Phase Crossings in Two-Phase Flow
DEFF Research Database (Denmark)
Madsen, Søren; Veje, Christian; Willatzen, Morten
2012-01-01
of the variables and are usually very slow to evaluate. To overcome these challenges, we use an interpolation scheme with local refinement. The simulations show that the method handles crossing of the saturation lines for both liquid to two-phase and two-phase to gas regions. Furthermore, a novel result obtained...... in this work, the method is stable towards dynamic transitions of the inlet/outlet boundaries across the saturation lines. Results for these cases are presented along with a numerical demonstration of conservation of mass under dynamically varying boundary conditions. Finally we present results...
Treating Chronic Myeloid Leukemia by Phase
... Myeloid Leukemia (CML) Treating Chronic Myeloid Leukemia Treating Chronic Myeloid Leukemia by Phase Treatment options for people ... a stem cell donor with matching tissue type. Chronic phase The standard treatment for chronic phase CML ...
Noise-induced synchronization for phase turbulence
Sakaguchi, H.
2003-01-01
Phase turbulence is suppressed by applying common noise additively to the Kuramoto-Sivashinsky type equation, and the noise-induced phase synchronization is realized. The noise strength necessary for the suppression of phase turbulence is evaluated theoretically.
Phases of cannibal dark matter
Farina, Marco; Pappadopulo, Duccio; Ruderman, Joshua T.; Trevisan, Gabriele
2016-12-01
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background.
Random Phases and Energy Dispersion
Institute of Scientific and Technical Information of China (English)
刘全慧; 刘天贵; 班卫全
2003-01-01
Using 2N + 1 successive stationary states centred at nth, we construct a rectangular wavepacket in which the stationary states are superimposed with the equal weight √2N + 1. With the requirement of the wavepacket to be a quasi-classical state, the number N is determined by minimizing the uncertainty △x△p. Since the stationary state can only be determined to within an arbitrary multiplicative complex phase factor of unit magnitude, a number of N is obtained as a set of the phases are given. For a harmonic oscillator, when all of the phase factors are essentially the same, we have N ≈ [61/3n2/3] with [x] signifying the integral part of positive number x. When every phase in the phase factors is given by a random number generated in a closed interval [0, 2π] and when n ≥ 10, the probability of appearance of N is roughly 1/2N when N = 1 to 7, and does not exceed 0.01 whenN ≥ 8.
Suvarna, Viraj
2010-04-01
Not all Phase IV studies are post-marketing surveillance (PMS) studies but every PMS study is a phase IV study. Phase IV is also an important phase of drug development. In particular, the real world effectiveness of a drug as evaluated in an observational, non-interventional trial in a naturalistic setting which complements the efficacy data that emanates from a pre-marketing randomized controlled trial (RCT). No matter how many patients are studied pre-marketing in a controlled environment, the true safety profile of a drug is characterized only by continuing safety surveillance through a spontaneous adverse event monitoring system and a post-marketing surveillance/non-interventional study. Prevalent practice patterns can generate leads that could result in further evaluation of a new indication via the RCT route or even a signal that may necessitate regulatory action (change in labeling, risk management/minimization action plan). Disease registries are another option as are the large simple hybrid trials. Surveillance of spontaneously reported adverse events continues as long as a product is marketed. And so Phase IV in that sense never ends.
Directory of Open Access Journals (Sweden)
Viraj Suvarna
2010-01-01
Full Text Available Not all Phase IV studies are post-marketing surveillance (PMS studies but every PMS study is a phase IV study. Phase IV is also an important phase of drug development. In particular, the real world effectiveness of a drug as evaluated in an observational, non-interventional trial in a naturalistic setting which complements the efficacy data that emanates from a pre-marketing randomized controlled trial (RCT. No matter how many patients are studied pre-marketing in a controlled environment, the true safety profile of a drug is characterized only by continuing safety surveillance through a spontaneous adverse event monitoring system and a post-marketing surveillance/non-interventional study. Prevalent practice patterns can generate leads that could result in further evaluation of a new indication via the RCT route or even a signal that may necessitate regulatory action (change in labeling, risk management/minimization action plan. Disease registries are another option as are the large simple hybrid trials. Surveillance of spontaneously reported adverse events continues as long as a product is marketed. And so Phase IV in that sense never ends.
Modeling of phased array transducers.
Ahmad, Rais; Kundu, Tribikram; Placko, Dominique
2005-04-01
Phased array transducers are multi-element transducers, where different elements are activated with different time delays. The advantage of these transducers is that no mechanical movement of the transducer is needed to scan an object. Focusing and beam steering is obtained simply by adjusting the time delay. In this paper the DPSM (distributed point source method) is used to model the ultrasonic field generated by a phased array transducer and to study the interaction effect when two phased array transducers are placed in a homogeneous fluid. Earlier investigations modeled the acoustic field for conventional transducers where all transducer points are excited simultaneously. In this research, combining the concepts of delayed firing and the DPSM, the phased array transducers are modeled semi-analytically. In addition to the single transducer modeling the ultrasonic fields from two phased array transducers placed face to face in a fluid medium is also modeled to study the interaction effect. The importance of considering the interaction effect in multiple transducer modeling is discussed, pointing out that neighboring transducers not only act as ultrasonic wave generators but also as scatterers.
Phases of cannibal dark matter
Energy Technology Data Exchange (ETDEWEB)
Farina, Marco [New High Energy Theory Center, Department of Physics, Rutgers University,136 Frelinghuisen Road, Piscataway, NJ 08854 (United States); Pappadopulo, Duccio; Ruderman, Joshua T.; Trevisan, Gabriele [Center for Cosmology and Particle Physics, Department of Physics, New York University,New York, NY 10003 (United States)
2016-12-13
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background.
Phase-field simulation of liquid phase migration in the WC-Co system during liquid phase sintering
Energy Technology Data Exchange (ETDEWEB)
Cheng, Kaiming; Zhang, Lijun; Du, Yong [Central South Univ., Changsha (China). State Key Lab. of Powder Metallurgy; Schwarze, Christian; Steinbach, Ingo [Bochum Univ. (Germany). Interdisciplinary Centre for Advanced Materials Simulation
2016-04-15
Liquid phase sintering is a process for forming high performance, multiple-phase components from powders. The process includes very complex interactions between various mass transportation phenomena, among which the liquid phase migration represents an important one in the aspect of forming a gradient structure in cemented carbide. In the present work, phase-field simulation of the liquid phase migration phenomenon during liquid phase sintering is performed in the WC-Co based cemented carbide. The simulation results are analyzed and compared with the experimentally determined key factors of microstructural evolution, such as contiguity and liquid phase migration rate. The diffusion-controlled solution-precipitation mechanism of the liquid phase migration process in the cemented carbide system is confirmed from the current simulation result, which provides deeper understanding of the microstructural evolution during the liquid phase migration process. These simulations can offer guidance in preventing the liquid phase migration process during liquid phase sintering of cellular cemented carbide.
Origin and use of crystallization phase diagrams.
Rupp, Bernhard
2015-03-01
Crystallization phase diagrams are frequently used to conceptualize the phase relations and also the processes taking place during the crystallization of macromolecules. While a great deal of freedom is given in crystallization phase diagrams owing to a lack of specific knowledge about the actual phase boundaries and phase equilibria, crucial fundamental features of phase diagrams can be derived from thermodynamic first principles. Consequently, there are limits to what can be reasonably displayed in a phase diagram, and imagination may start to conflict with thermodynamic realities. Here, the commonly used `crystallization phase diagrams' are derived from thermodynamic excess properties and their limitations and appropriate use is discussed.
Shock dynamics of phase diagrams
Moro, Antonio
2014-01-01
A thermodynamic phase transition denotes a drastic change of state of a physical system due to a continuous change of thermodynamic variables, as for instance pressure and temperature. The classical van der Waals equation of state is the simplest model that predicts the occurrence of a critical point associated with the gas-liquid phase transition. Nevertheless, below the critical temperature, theoretical predictions of the van der Waals theory significantly depart from the observed physical behaviour. We develop a novel approach to classical thermodynamics based on the solution of Maxwell relations for a generalised family of nonlocal entropy functions. This theory provides an exact mathematical description of discontinuities of the order parameter within the phase transition region, it explains the universal form of the equations of state and the occurrence of triple points in terms of the dynamics of nonlinear shock wave fronts.
Guiding light via geometric phases
Slussarenko, Sergei; Jisha, Chandroth P; Piccirillo, Bruno; Santamato, Enrico; Assanto, Gaetano; Marrucci, Lorenzo
2015-01-01
Known methods for transverse confinement and guidance of light can be grouped into a few basic mechanisms, the most common being metallic reflection, total internal reflection and photonic-bandgap (or Bragg) reflection. All of them essentially rely on changes of the refractive index, that is on scalar properties of light. Recently, processes based on "geometric Berry phases", such as manipulation of polarization states or deflection of spinning-light rays, have attracted considerable interest in the contexts of singular optics and structured light. Here, we disclose a new approach to light waveguiding, using geometric Berry phases and exploiting polarization states and their handling. This can be realized in structured three-dimensional anisotropic media, in which the optic axis lies orthogonal to the propagation direction and is modulated along it and across the transverse plane, so that the refractive index remains constant but a phase distortion can be imposed on a beam. In addition to a complete theoretic...
Phase Transformations in Confined Nanosystems
Energy Technology Data Exchange (ETDEWEB)
Shield, Jeffrey E. [Department of Mechanical & Materials Engineering; Belashchenko, Kirill [Department of Physics & Astronomy
2014-04-29
This project discovered that non-equilibrium structures, including chemically ordered structures not observed in bulk systems, form in isolated nanoscale systems. Further, a generalized model was developed that effectively explained the suppression of equilibrium phase transformations. This thermodynamic model considered the free energy decrease associated with the phase transformation was less than the increase in energy associated with the formation of an interphase interface, therefore inhibiting the phase transformation. A critical diameter exists where the system transitions to bulk behavior, and a generalized equation was formulated that successfully predicted this transition in the Fe-Au system. This provided and explains a new route to novel structures not possible in bulk systems. The structural characterization was accomplished using transmission electron microscopy in collaboration with Matthew Kramer of Ames Laboratory. The PI and graduate student visited Ames Laboratory several times a year to conduct the experiments.
CERN openlab enters fifth phase
Andrew Purcell
2015-01-01
CERN openlab is a unique public-private partnership between CERN and leading ICT companies. At the start of this year, openlab officially entered its fifth phase, which will run until the end of 2017. For the first time in its history, it has extended beyond the CERN community to include other major European and international research laboratories. Founded in 2001 to develop the innovative ICT systems needed to cope with the unprecedented computing challenges of the LHC, CERN openlab unites science and industry at the cutting edge of research and innovation. In a white paper published last year, CERN openlab set out the main ICT challenges it will tackle during its fifth phase, namely data acquisition, computing platforms, data storage architectures, computer management and provisioning, networks and connectivity, and data analytics. As it enters its fifth phase, CERN openlab is expanding to include other research laboratories. "Today, research centres in other disciplines are also st...
Phase control of excitable systems
Energy Technology Data Exchange (ETDEWEB)
Zambrano, S; Seoane, J M; Marino, I P; Sanjuan, M A F [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Euzzor, S; Meucci, R; Arecchi, F T [CNR-Istituto Nazionale di Ottica Applicata, Largo E. Fermi, 6 50125 Firenze (Italy)], E-mail: samuel.zambrano@urjc.es, E-mail: jesus.seoane@urjc.es, E-mail: ines.perez@urjc.es
2008-07-15
Here we study how to control the dynamics of excitable systems by using the phase control technique. Excitable systems are relevant in neuronal dynamics and therefore this method might have important applications. We use the periodically driven FitzHugh-Nagumo (FHN) model, which displays both spiking and non-spiking behaviours in chaotic or periodic regimes. The phase control technique consists of applying a harmonic perturbation with a suitable phase {phi} that we adjust in search of different behaviours of the FHN dynamics. We compare our numerical results with experimental measurements performed on an electronic circuit and find good agreement between them. This method might be useful for a better understanding of excitable systems and different phenomena in neuronal dynamics.
Physicochemical Perturbations of Phase Equilibriums
Dobruskin, Vladimir Kh
2010-01-01
The alternative approach to the displacement of gas/liquid equilibrium is developed on the basis of the Clapeyron equation. The phase transition in the system with well-established properties is taken as a reference process to search for the parameters of phase transition in the perturbed equilibrium system. The main equation, derived in the framework of both classical thermodynamics and statistical mechanics, establishes a correlation between variations of enthalpies of evaporation, \\Delta (\\Delta H), which is induced by perturbations, and the equilibrium vapor pressures. The dissolution of a solute, changing the surface shape, and the effect of the external field of adsorbents are considered as the perturbing actions on the liquid phase. The model provides the unified method for studying (1) solutions, (2) membrane separations (3) surface phenomena, and (4) effect of the adsorption field; it leads to the useful relations between \\Delta (\\Delta H), on the one hand, and the osmotic pressures, the Donnan poten...
Phase preservation in musical signals
Vijayakumar, V.; Eswaran, C.
2005-04-01
The intensity variations of the harmonics of musical instruments in the frequency domain can be interpreted to store phase information. The motivation for this arises by considering the similarity of the timbre of in- struments to that obtained through a diffraction model proposed here. The intensity modifications of an input spectrum of discrete frequencies of unit intensity into the known spectra of different musical instruments have been found to match that of known instruments. According to diffraction theory, the modifying envelope encodes phase information. By considering the similarity, it is proposed that musical instrument timbre store phase information. It is suggested that timbre itself could have diffraction origins. Specific examples of musical instruments are considered to illustrate this intepretation.
Phase diagram of ammonium nitrate
Dunuwille, M.; Yoo, C. S.
2014-05-01
Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.
GPC and quantitative phase imaging
Palima, Darwin; Bañas, Andrew Rafael; Villangca, Mark Jayson; Glückstad, Jesper
2016-03-01
Generalized Phase Contrast (GPC) is a light efficient method for generating speckle-free contiguous optical distributions using binary-only or analog phase levels. It has been used in applications such as optical trapping and manipulation, active microscopy, structured illumination, optical security, parallel laser marking and labelling and recently in contemporary biophotonics applications such as for adaptive and parallel two-photon optogenetics and neurophotonics. We will present our most recent GPC developments geared towards these applications. We first show a very compact static light shaper followed by the potential of GPC for biomedical and multispectral applications where we experimentally demonstrate the active light shaping of a supercontinuum laser over most of the visible wavelength range. Finally, we discuss how GPC can be advantageously applied for Quantitative Phase Imaging (QPI).
Griffiths phases on complex networks.
Muñoz, Miguel A; Juhász, Róbert; Castellano, Claudio; Odor, Géza
2010-09-17
Quenched disorder is known to play a relevant role in dynamical processes and phase transitions. Its effects on the dynamics of complex networks have hardly been studied. Aimed at filling this gap, we analyze the contact process, i.e., the simplest propagation model, with quenched disorder on complex networks. We find Griffiths phases and other rare-region effects, leading rather generically to anomalously slow (algebraic, logarithmic, …) relaxation, on Erdos-Rényi networks. Similar effects are predicted to exist for other topologies with a finite percolation threshold. More surprisingly, we find that Griffiths phases can also emerge in the absence of quenched disorder, as a consequence of topological heterogeneity in networks with finite topological dimension. These results have a broad spectrum of implications for propagation phenomena and other dynamical processes on networks.
Phased arrays: inline flow line hub inspection using phased arrays
Bloom, J.G.P.; Chougrani, K.; Rundberg, H.; Oldenziel, G.; Deleye, X.; Martina, Q.
2011-01-01
The feasibility of the inspection of flow line hubs using the phased array technique was investigated to determine the surface area of the seal area degraded by corrosion. A clean model of the hub was simulated to gain insight into the geometrical echoes and to determine the area covered by the ultr
The comfortable driving model revisited: Traffic phases and phase transitions
Knorr, Florian
2013-01-01
We study the spatiotemporal patterns resulting from different boundary conditions for a microscopic traffic model and contrast it with empirical results. By evaluating the time series of local measurements, the local traffic states are assigned to the different traffic phases of Kerner's three-phase traffic theory. For this classification we use the rule-based FOTO-method, which provides `hard' rules for this assignment. Using this approach, our analysis shows that the model is indeed able to reproduce three qualitatively different traffic phases: free flow (F), synchronized traffic (S), and wide moving jams (J). In addition, we investigate the likelihood of transitions between the three traffic phases. We show that a transition from free flow (F) to a wide moving jam (J) often involves an intermediate transition; first from free flow F to synchronized flow S and then from synchronized flow to a wide moving jam. This is supported by the fact that the so called F->S transition (from free flow to synchronized t...
Biometeorological phases influence pedestrian trauma
Directory of Open Access Journals (Sweden)
Gajić Vladimir
2011-01-01
Full Text Available Introduction. Biometeorological circumstances have a big influence on all traffic participants, especially reflexes, moving coordination and perception ability. With a lower attention and drivers’ and pedestrians’ concentration, there was a larger amount of pedestrian trauma in certain biometeorological phases. Objective. The aim of this study was to establish the correlation between pedestrian trauma and biometeorological phases. Methods. The comparative analysis of everyday biometeorological phases for the city of Kragujevac determined by RHMI and the evidence of knocked-down pedestrians from the Kragujevac traffic police for the period 2003-2008. Results. There were 6,127 accidents, with 696 knocked pedestrians in 666 (10.87% accidents. Most of them happened in 2003 (135, and the fewest in 2005 (90. Most accidents were during December (74, the fewest were in June (46. The fewest accidents were during 04-05-06 hour interval (by 2, most during 13-14 hours (61. There were 374 males and 349 females. Most of the males (by 60 were 0-10 and 11-20 years old, most of the females (74 were 11-20 years old. There were 443 pedestrians who suffered slight body injuries (112 were 11-20, 225 suffered heavy and 28 had lethal injuries (most over 70. As provokers, the pedestrians suffered because of improper crossing roads (185, while as a casualties, they suffered due to speeding of vechicles (285. Most accidents happened in biometeorological phases 4 (168 and 9 (151, the fewest in phase 10 (4. Conclussion. Statistical analysis shows a significant correlation between pedestrians’ accidents and biometeorological phases, when the most accidents occurred during penetrations of cold fronts, while there was a sudden switch of weather conditions from warm-dry to cold-wet weather.
EHF multifunction phased array antenna
Solbach, Klaus
1986-07-01
The design of a low cost demonstration EHF multifunction-phased array antenna is described. Both, the radiating elements and the phase-shifter circuits are realized on microstrip substrate material in order to allow photolithographic batch fabrication. Self-encapsulated beam-lead PIN-diodes are employed as the electronic switch elements to avoid expensive hermetic encapsulation of the semiconductors or complete circuits. A space-feed using a horn-radiator to illuminate the array from the front-side is found to be the simplest and most inexpensive feed. The phased array antenna thus operates as a reflect-array, the antenna elements employed in a dual role for the collection of energy from the feed-horn and for the re-radiation of the phase-shifted waves (in transmit-mode). The antenna is divided into modules containing the radiator/phase-shifter plate plus drive- and BITE-circuitry at the back. Both drive- and BITE-components use gate-array integrated circuits especially designed for the purpose. Several bus-systems are used to supply bias and logical data flows to the modules. The beam-steering unit utilizes several signal processors and high-speed discrete adder circuits to combine the pointing, frequency and beam-shape information from the radar system computer with the stored phase-shift codes for the array elements. Since space, weight and power consumption are prime considerations only the most advanced technology is used in the design of both the microwave and the digital/drive circuitry.
Scrutinizing the pion condensed phase
Energy Technology Data Exchange (ETDEWEB)
Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)
2017-02-15
When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)
Fractional vortex dipole phase filter
Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam
2014-10-01
In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.
Phase out of incandescent lamps
Energy Technology Data Exchange (ETDEWEB)
NONE
2010-07-01
Since early 2007 almost all OECD and many non-OECD governments have announced policies aimed at phasing-out incandescent lighting within their jurisdictions. This study considers the implications of these policy developments in terms of demand for regulatory compliant lamps and the capacity and motivation of the lamp industry to produce efficient lighting products in sufficient volume to meet future demand. To assess these issues, it reviews the historic international screw-based lamp market, describes the status of international phase-out policies and presents projections of anticipated market responses to regulatory requirements to determine future demand for CFLs.
DEFF Research Database (Denmark)
Thomsen, P.E.B.; Jørgensen, R.M.; Kanters, J.K.
2005-01-01
phase 2 reentry, demonstrated in animal experiments to initiate ventricular extrasystoles, ventricular tachycardia, and ventricular fibrillation, also plays a role in humans. METHODS We examined 18 patients with ventricular extrasystoles and/or ventricular tachycardia by signal averaging of the ECG......-wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments...
Closure phase and lucky imaging.
Rhodes, William T
2009-01-01
Since its introduction by Jennison in 1958, the closure-phase method for removing the effects of electrical path-length errors in radio astronomy and of atmospheric turbulence in optical astronomy has been based on the non-redundant-spacing triple interferometer. It is shown that through application of lucky imaging concepts it is possible to relax this condition, making closure-phase methods possible with redundantly spaced interferometer configurations and thereby widening their range of application. In particular, a quadruple-interferometer can, under lucky imaging conditions, be treated as though it were a triple interferometer. The slit-annulus aperture is investigated as a special case.
Robust Adaptive Quantum Phase Estimation
Roy, Shibdas; Huntington, Elanor H
2014-01-01
Quantum parameter estimation is central to many fields such as quantum computation, communications and metrology. Optimal estimation theory has been instrumental in achieving the best accuracy in quantum parameter estimation, which is possible when we have very precise knowledge of and control over the model. However, uncertainties in key parameters underlying the system are unavoidable and may impact the quality of the estimate. We show here how quantum optical phase estimation of a squeezed state of light exhibits improvement when using a robust fixed-interval smoother designed with uncertainties explicitly introduced in parameters underlying the phase noise.
Thermal Phase in Bubbling Geometries
Institute of Scientific and Technical Information of China (English)
LIU Chang-Yong
2008-01-01
We use matrix model to study thermal phase in bubbling half-BPS type IIB geometries with SO(4)×SO(4) symmetry.Near the horizon limit,we find that thermal vacua of bubbling geometries have disjoint parts,and each part is one kind of phase of the thermal system.We connect the thermal dynamics of bubbling geometries with one-dimensional fermions thermal system.Finally,we try to give a new possible way to resolve information loss puzzle.
DEFF Research Database (Denmark)
Jensen, Knud Jørgen
2013-01-01
This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective.......This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....
Phase Transformation of Nanosized Zirconia
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the syn- thesis parameters such as OH-/Zr molar ratio, crystallizing temperature and time. It can be trans- formed among amorphous, tetragonal and monoclinic phases. The transformation is driven by particle size. The research shows the nanocrystalline zirconia possesses the higher thermal stability compared with amorphous framework. The "glow exotherm" can be observed for the amorphous samples. Otherwise, it is in the absence for nanocrystalline samples. Herein, the reason for retention of tetragonal zirconia is demonstrated.
The Generalised Phase Contrast Method
DEFF Research Database (Denmark)
Glückstad, Jesper
. Optimal conditions for visibility, peak irradiance and accuracy are derived and shown to be perfectly in line with empirical results from the literature. New graphic methods for advanced analysis purposes are demonstrated supporting these conclusions as well as providing new tools for innovative filter...... designs and parameter settings. Finally, a number of original applications facilitated by the parallel light-beam encoding of the Generalised Phase Contrast method are briefly outlined. These include among others, wavefront sensing and generation, advanced usercontrolled optical micro......-manipulation, optical phase-only encryption/decryption and fully integrated micro-optical implementations....
Nguyen, Hung D.; Steele, Gynelle C.
2016-01-01
This report outlines the 2015 Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) Phase I, Phase II, and Post-Phase II opportunity contract award results associated with NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD) for NASA Glenn Research Center. The report also highlights the number of Phase I, Phase II, and Post-Phase II contracts awarded by mission directorate. The 2015 Phase I contract awards to companies in Ohio and their corresponding technologies are also discussed.
Phase transformations in metallic glasses
DEFF Research Database (Denmark)
Jiang, Jianzhong
2003-01-01
Recent development of grain-size effect on phase transformations induced by pressure is reported. A thermodynamic theory is presented and three components: the ratio of volume collapses, the surface energy differences, and the internal energy differences, governing the change of transition pressu...
Super-resolution Phase Tomography
Depeursinge, Christian
2013-04-21
Digital Holographic Microscopy (DHM) yields reconstructed complex wavefields. It allows synthesizing the aperture of a virtual microscope up to 2π, offering super-resolution phase images. Live images of micro-organisms and neurons with resolution less than 100 nm are presented.
GPC and quantitative phase imaging
DEFF Research Database (Denmark)
Palima, Darwin; Banas, Andrew Rafael; Villangca, Mark Jayson
2016-01-01
shaper followed by the potential of GPC for biomedical and multispectral applications where we experimentally demonstrate the active light shaping of a supercontinuum laser over most of the visible wavelength range. Finally, we discuss how GPC can be advantageously applied for Quantitative Phase Imaging...
Symmetry structure and phase transitions
Indian Academy of Sciences (India)
Ashok Goyal; Meenu Dahiya; Deepak Chandra
2003-05-01
We study chiral symmetry structure at ﬁnite density and temperature in the presence of external magnetic ﬁeld and gravity, a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of phase transition in the expanding early Universe and possible formation of quark nuggets and their survival.
Advances phase-lock techniques
Crawford, James A
2008-01-01
From cellphones to micrprocessors, to GPS navigation, phase-lock techniques are utilized in most all modern electronic devices. This high-level book takes a systems-level perspective, rather than circuit-level, which differentiates it from other books in the field.
Calibrating for Ionospheric Phase Delays
Macdoran, P. F.
1985-01-01
Technique determines ionospheric phase delay on real-time universally applicable basis in terms of electrons per meter squared by coherently modulating two L-band carrier frequencies received from two Global Positioning System satelites. Two pseudorandom number sequences cross-correlated to derive delay time.
SOLID PHASE SYNTHESIS OF ISOXAZOLINES
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin isreported. 2-Polystyrylsuifonamidoethanol resin 1 was reacted with acryloyl chloride to afford2-polystyrylsulfonylamidoethyl acrylate resin 2, which was further reacted with brominatedaldoximes by [3+2] cycioaddition to give isoxazoline resin 4. Resin 4 was treated with aqueous 6mol/L HCI solution to obtain isoxazolines in good yield and purity.
Multiple solid-phase microextraction
Koster, EHM; de Jong, GJ
2000-01-01
Theoretical aspects of multiple solid-phase microextraction are described and the principle is illustrated with the extraction of lidocaine from aqueous solutions. With multiple extraction under non-equilibrium conditions considerably less time is required in order to obtain an extraction yield that
Experimental Blade Research - phase 2
DEFF Research Database (Denmark)
Eder, Martin Alexander; Branner, Kim; Berring, Peter
This report is a summary of the results obtained in the project: Experimental Blade Research – phase 2 (EBR2). The project was supported by the Danish Energy Authority through the 2010 Energy Technology Development and Demonstration Program (EUDP 2010-II) and has journal no. 64011-0006. The project...
Energy Technology Data Exchange (ETDEWEB)
Wagner, Victoria [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Collaboration: GERDA-Collaboration
2016-07-01
The GERDA experiment is designed to search for neutrinoless double beta (0νββ) decay of {sup 76}Ge. In Phase I of the experiment a background index (BI) of 10{sup -2} cts/(keV.kg.yr) was reached. No signal has been found and a lower limit on the half-life of 2.1.10{sup 25} yr (at 90% C.L.) is extracted. The aim of Phase II is to double the Ge mass and further reduce the BI by an order of magnitude to explore half-lives of about 10{sup 26} yr. Thirty new Broad Energy Germanium (BEGe) detectors have been produced. These detectors are distinct for their improved energy resolution and enhanced pulse shape discrimination of signal from background events. Further background reduction will be reached by an active veto to read out argon scintillation light. The Phase II commissioning showed that two of the major background components, external γ-rays from {sup 214}Bi and {sup 208}Tl decays, can be suppressed up to two orders of magnitude. This talk presents the current status of the GERDA Phase II upgrade.
Phase-selective quantum eraser
Heuer, A.; Pieplow, G.; Menzel, R.
2015-07-01
A quantum-eraser experiment is reported with photon pairs generated by two synchronously pumped parametric down-converters coupled via induced coherence. The complementarity between which-source information and two-photon interference fringe visibility is demonstrated explicitly. Changing the phase in a Mach-Zehnder interferometer allows a continuous transition from wavelike to particlelike behavior of photons.
Beyond the random phase approximation
DEFF Research Database (Denmark)
Olsen, Thomas; Thygesen, Kristian S.
2013-01-01
We assess the performance of a recently proposed renormalized adiabatic local density approximation (rALDA) for ab initio calculations of electronic correlation energies in solids and molecules. The method is an extension of the random phase approximation (RPA) derived from time-dependent density...
Relativistic phase space dimensional recurrences
Delbourgo, Robert
2003-01-01
We derive recurrence relations between phase space expressions in different dimensions by confining some of the coordinates to tori or spheres of radius $R$ and taking the limit as $R \\to \\infty$. These relations take the form of mass integrals, associated with extraneous momenta (relative to the lower dimension), and produce the result in the higher dimension.
Scrutinizing the pion condensed phase
Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo; Pagliaroli, Giulia
2016-01-01
When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid in the normal phase and close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to ...
DEFF Research Database (Denmark)
Margheritini, Lucia
Cylinder Phase 1: proof of concept and first optimization”, DCE report 115, ISSN 1901-726X, and it is recommended that the two are consulted together as they were firstly agreed to be in one document. The present report aims at estimate the efficiency of the Rolling Cylinder long model (previously...
Phase diagram of Hertzian spheres
Pàmies, J.C.; Cacciuto, A.; Frenkel, D.
2009-01-01
We report the phase diagram of interpenetrating Hertzian spheres. The Hertz potential is purely repulsive, bounded at zero separation, and decreases monotonically as a power law with exponent 5/2, vanishing at the overlapping threshold. This simple functional describes the elastic interaction of wea
Backyard Astronomy: Observing Moon Phases.
Brandou, Bob
1997-01-01
Presents an activity involving the observation of moon phases that can provide a one-on-one learning experience and stimulate interaction between a child and an adult family member. This activity can also be initiated by teachers and outcomes can be integrated into the classroom science curriculum. (JRH)
Phase transitions in finite systems
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire
2002-07-01
In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)
Crichton's phase-shift ambiguity
Atkinson, D.; Johnson, P.W.; Mehta, N.; Roo, M. de
1973-01-01
A re-examination of the SPD phase-shift ambiguity is made with a view to understanding certain singular features of the elastic unitarity constraint. An explicit solution of Crichton's equations is presented, and certain features of this solution are displayed graphically. In particular, it is shown
Nonclassicality in phase-number uncertainty relations
Energy Technology Data Exchange (ETDEWEB)
Matia-Hernando, Paloma; Luis, Alfredo [Departamento de Optica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)
2011-12-15
We show that there are nonclassical states with lesser joint fluctuations of phase and number than any classical state. This is rather paradoxical since one would expect classical coherent states to be always of minimum uncertainty. The same result is obtained when we replace phase by a phase-dependent field quadrature. Number and phase uncertainties are assessed using variance and Holevo relation.
Phase control system for SSRF linac
Institute of Scientific and Technical Information of China (English)
YIN Chongxian; YU Luyang; LIU Dekang
2008-01-01
The design of phase control system in Shanghai Synchrotron Radiation Facility (SSRF) linac is presented in this paper. And digital phase detecting algorithm, the key for phase control system, is fully described. The testing results for phase control system in 100MeV linac are discussed in detail.
Fourier Phase Domain Steganography: Phase Bin Encoding Via Interpolation
Rivas, Edward
2007-04-01
In recent years there has been an increased interest in audio steganography and watermarking. This is due primarily to two reasons. First, an acute need to improve our national security capabilities in light of terrorist and criminal activity has driven new ideas and experimentation. Secondly, the explosive proliferation of digital media has forced the music industry to rethink how they will protect their intellectual property. Various techniques have been implemented but the phase domain remains a fertile ground for improvement due to the relative robustness to many types of distortion and immunity to the Human Auditory System. A new method for embedding data in the phase domain of the Discrete Fourier Transform of an audio signal is proposed. Focus is given to robustness and low perceptibility, while maintaining a relatively high capacity rate of up to 172 bits/s.
Phase transformations in intermetallic phases in zirconium alloys
Energy Technology Data Exchange (ETDEWEB)
Filippov, V. P., E-mail: vpfilippov@mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Kirichenko, V. G. [Kharkiv National Karazin University (Ukraine); Salomasov, V. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Khasanov, A. M. [University of North Carolina – Asheville, Chemistry Department (United States)
2017-11-15
Phase change was analyzed in intermetallic compounds of zirconium alloys (Zr – 1.03 at.% Fe; Zr – 0.51 at.% Fe; Zr – 0.51 at.% Fe – M(M = Nb, Sn). Mössbauer spectroscopy on {sup 57}Fe nuclei in backscattering geometry with the registration of the internal conversion electrons and XRD were used. Four types of iron bearing intermetallic compounds with Nb were detected. A relationship was found between the growth process of intermetallic inclusions and segregation of these phases. The growth kinetics of inclusions possibly is not controlled by bulk diffusion, and a lower value of the iron atom’s activation energy of migration can be attributed to the existence of enhanced diffusion paths and interface boundaries.
Nanostructures having crystalline and amorphous phases
Mao, Samuel S; Chen, Xiaobo
2015-04-28
The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.
IMPROVEMENT OF PHASE GRADIENT AUTOFOCUS ALGORITHM
Institute of Scientific and Technical Information of China (English)
1998-01-01
The phase error estimated by phase gradient autofocus(PGA) is not based on a finite order polynomial mode, so PGA has a good autofocus property for arbitrary order phase error and is fit for high resolution airborne SAR. But PGA has two shortcomings: first, it has a worse estimation property for fast changing phase error; second, there exists a section of linear phase in the phase error estimated by this algorithm. This paper introduces the idea of rank one phase estimate (ROPE) autofocus technique, and improves PGA. The improved PGA(IPGA) can successfully overcome both these shortcomings of PGA.
Analysis of phase regeneration of DPSK/DQPSK signals based on Phase-sensitive amplification
Institute of Scientific and Technical Information of China (English)
Xianfeng Tang; Xiaoguang Zhang; Lixia Xi
2009-01-01
Amplification and phase regeneration can be realized using a phase-sensitive amplifier(PSA).The phase regeneration of differential phase-shift keying(DPSK)signals based on PSA is analyzed theoretically.We realize the phase regeneration of differential quadrature phase-shift keying(DQPSK)signals based on a structure using two balanced PSAs.Simulations show that nearly ideal phase regeneration can be achieved for the DPSK/DQPSK signals.
Phases of holographic d-wave superconductor
Krikun, A.
2015-01-01
We study different phases in the holographic model of d-wave superconductor. These are described by solutions to the classical equations of motion found in different ansatze. Apart from the known homogeneous d-wave superconducting phase we find three new solutions. Two of them represent two distinct families of the spatially modulated solutions, which realize the charge density wave phases in the dual theory. The third one is the new homogeneous phase with nonzero anapole moment. These phases...
Adiabatic geometric phases in hydrogenlike atoms
Sjöqvist, Erik; Yi, X. X.; Åberg, J.
2005-01-01
We examine the effect of spin-orbit coupling on geometric phases in hydrogenlike atoms exposed to a slowly varying magnetic field. The marginal geometric phases associated with the orbital angular momentum and the intrinsic spin fulfill a sum rule that explicitly relates them to the corresponding geometric phase of the whole system. The marginal geometric phases in the Zeeman and Paschen-Back limit are analyzed. We point out the existence of nodal points in the marginal phases that may be det...
A New Phase Noise Detection Method
Yan, Gangfeng
2015-01-01
Phase noise is one of the most important parameters in many oscillators. Detecting accurately phase noise for oscillators has importance significance. In this paper, based on correlation operation detection phase noise for oscillators was proposed. This method not only can save a high precision reference oscillator, but also can detect accurately the phase noise of measured oscillator in theory. Detected phase noise of oscillators using this method has very strong utility value.
The VLA Atmospheric Phase Interferometer
Morris, Keith
2014-05-01
The Atmospheric Phase Interferometer (API) is a two-element atmospheric seeing monitor located at the Very Large Array (VLA) site. The instrument measures turbulent refractive index variation through the atmosphere by examining phase differences in a satellite beacon signal detected at two (or more) antennas. With this measurement, the VLA scheduling software is able to consider atmospheric stability when determining which frequency observation to schedule next. We are in the process of extending this two-element interferometer to four elements, which will allow us to measure the turbulence in two dimensions and at multiple length scales. This thesis will look at some statistical properties of turbulence, the effects of atmospheric stability on radio interferometric observations, and discuss details of the instrument and the data that it collects. The thesis will also cover some techniques and principles of signal processing, and an analysis of some data from the instrument. The results demonstrate that other surface atmospheric variables (e.g. windspeed, water vapor pressure) show the same structure function exponent as the atmospheric phase fluctuations. In particular, the structure functions of water vapor partial pressure and wind speed show the same exponent as the phase. Though the agreement between meteorological variables and atmospheric phase is scientifically satisfying, these surface measurements are not nearly as sensitive as the API saturation phase measurement, and therefore cannot be used to schedule telescope time in its stead. What is informative about these results is that the similar structure functions for API and meteorological data are detecting reinforce the claim that both measurements represent turbulent transport, and not instrumental noise. Data from the instrument reveals that measurements are consistent with both Kolmogorov turbulence theory, and with prior observations. The API predominately measures three-dimensional isotropic
Multiphase, multicomponent phase behavior prediction
Dadmohammadi, Younas
Accurate prediction of phase behavior of fluid mixtures in the chemical industry is essential for designing and operating a multitude of processes. Reliable generalized predictions of phase equilibrium properties, such as pressure, temperature, and phase compositions offer an attractive alternative to costly and time consuming experimental measurements. The main purpose of this work was to assess the efficacy of recently generalized activity coefficient models based on binary experimental data to (a) predict binary and ternary vapor-liquid equilibrium systems, and (b) characterize liquid-liquid equilibrium systems. These studies were completed using a diverse binary VLE database consisting of 916 binary and 86 ternary systems involving 140 compounds belonging to 31 chemical classes. Specifically the following tasks were undertaken: First, a comprehensive assessment of the two common approaches (gamma-phi (gamma-ϕ) and phi-phi (ϕ-ϕ)) used for determining the phase behavior of vapor-liquid equilibrium systems is presented. Both the representation and predictive capabilities of these two approaches were examined, as delineated form internal and external consistency tests of 916 binary systems. For the purpose, the universal quasi-chemical (UNIQUAC) model and the Peng-Robinson (PR) equation of state (EOS) were used in this assessment. Second, the efficacy of recently developed generalized UNIQUAC and the nonrandom two-liquid (NRTL) for predicting multicomponent VLE systems were investigated. Third, the abilities of recently modified NRTL model (mNRTL2 and mNRTL1) to characterize liquid-liquid equilibria (LLE) phase conditions and attributes, including phase stability, miscibility, and consolute point coordinates, were assessed. The results of this work indicate that the ϕ-ϕ approach represents the binary VLE systems considered within three times the error of the gamma-ϕ approach. A similar trend was observed for the for the generalized model predictions using
Coherent phase argument for inflation
Energy Technology Data Exchange (ETDEWEB)
Scott Dodelson
2004-03-17
Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion--inflation--from observations of anisotropies in the cosmic microwave background. First, the shape of the primordial spectrum is very similar to that predicted by generic inflation models. Second, the angular scale at which the first acoustic peak appears is consistent with the flat universe predicted by inflation. Here the author describes the third piece of evidence, perhaps the most convincing of all: the phase coherence needed to account for the clear peak/trough structure observed by the WMAP satellite and its predecessors. The author also discusses alternatives to inflation that have been proposed recently and explain how they produce coherent phases.
Phase Aberrations in Diffraction Microscopy
Energy Technology Data Exchange (ETDEWEB)
Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M
2005-09-29
In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.
Cavity Voltage Phase Modulation MD
Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department
2016-01-01
The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.
Agent review phase one report.
Energy Technology Data Exchange (ETDEWEB)
Zubelewicz, Alex Tadeusz; Davis, Christopher Edward; Bauer, Travis LaDell
2009-12-01
This report summarizes the findings for phase one of the agent review and discusses the review methods and results. The phase one review identified a short list of agent systems that would prove most useful in the service architecture of an information management, analysis, and retrieval system. Reviewers evaluated open-source and commercial multi-agent systems and scored them based upon viability, uniqueness, ease of development, ease of deployment, and ease of integration with other products. Based on these criteria, reviewers identified the ten most appropriate systems. The report also mentions several systems that reviewers deemed noteworthy for the ideas they implement, even if those systems are not the best choices for information management purposes.
Quantitative phase imaging of arthropods
Sridharan, Shamira; Katz, Aron; Soto-Adames, Felipe; Popescu, Gabriel
2015-01-01
Abstract. Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy. PMID:26334858
Three-phase Photovoltaic Systems
DEFF Research Database (Denmark)
Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo
2015-01-01
the grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view......Photovoltaic technology has experienced unprecedented growth in the last two decades, transforming from mainly off-grid niche generation to a major renewable energy technology, reaching approximately 180 GW of capacity worldwide at the end of 2014. Large photovoltaic power plants interfacing......, detailing the different photovoltaic inverter structures and topologies as well as discussing the different control layers within a grid-connected photovoltaic plant. Modulation schemes for various photovoltaic inverter topologies, grid synchronization, current control, active and reactive power control...
Undersampled Phase Retrieval with Outliers.
Weller, Daniel S; Pnueli, Ayelet; Divon, Gilad; Radzyner, Ori; Eldar, Yonina C; Fessler, Jeffrey A
2015-12-01
This paper proposes a general framework for reconstructing sparse images from undersampled (squared)-magnitude data corrupted with outliers and noise. This phase retrieval method uses a layered approach, combining repeated minimization of a convex majorizer (surrogate for a nonconvex objective function), and iterative optimization of that majorizer using a preconditioned variant of the alternating direction method of multipliers (ADMM). Since phase retrieval is nonconvex, this implementation uses multiple initial majorization vectors. The introduction of a robust 1-norm data fit term that is better adapted to outliers exploits the generality of this framework. The derivation also describes a normalization scheme for the regularization parameter and a known adaptive heuristic for the ADMM penalty parameter. Both 1D Monte Carlo tests and 2D image reconstruction simulations suggest the proposed framework, with the robust data fit term, reduces the reconstruction error for data corrupted with both outliers and additive noise, relative to competing algorithms having the same total computation.
Multiply Phased Traveling BPS Vortex
Kimm, Kyoungtae; Cho, Y M
2016-01-01
We present the multiply phased current carrying vortex solutions in the U(1) gauge theory coupled to an $(N+1)$-component SU(N+1) scalar multiplet in the Bogomolny limit. Our vortex solutions correspond to the static vortex dressed with traveling waves along the axis of symmetry. What is notable in our vortex solutions is that the frequencies of traveling waves in each component of the scalar field can have different values. The energy of the static vortex is proportional to the topological charge of $CP^N$ model in the BPS limit, and the multiple phase of the vortex supplies additional energy contribution which is proportional to the Noether charge associated to the remaining symmetry.
Machine learning phases of matter
Carrasquilla, Juan; Melko, Roger G.
2017-02-01
Condensed-matter physics is the study of the collective behaviour of infinitely complex assemblies of electrons, nuclei, magnetic moments, atoms or qubits. This complexity is reflected in the size of the state space, which grows exponentially with the number of particles, reminiscent of the `curse of dimensionality' commonly encountered in machine learning. Despite this curse, the machine learning community has developed techniques with remarkable abilities to recognize, classify, and characterize complex sets of data. Here, we show that modern machine learning architectures, such as fully connected and convolutional neural networks, can identify phases and phase transitions in a variety of condensed-matter Hamiltonians. Readily programmable through modern software libraries, neural networks can be trained to detect multiple types of order parameter, as well as highly non-trivial states with no conventional order, directly from raw state configurations sampled with Monte Carlo.
Fiber bundle phase conjugate mirror
Ward, Benjamin G.
2012-05-01
An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.
Electroweak phase transition recent results
Csikor, Ferenc
2000-01-01
Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.
Phase-domain photoacoustic sensing
Gao, Fei; Zhang, Ruochong; Feng, Xiaohua; Liu, Siyu; Ding, Ran; Kishor, Rahul; Qiu, Lei; Zheng, Yuanjin
2017-01-01
As one of the fastest-growing imaging modalities in recent years, photoacoustic imaging has attracted tremendous research interest for various applications including anatomical, functional, and molecular imaging. The majority of the photoacoustic imaging systems are based on the time-domain pulsed photoacoustic method, which utilizes a pulsed laser source to induce a wideband photoacoustic signal, revealing optical absorption contrast. An alternative way is the frequency-domain photoacoustic method utilizing the chirping modulation of laser intensity to achieve lower system cost. In this paper, we report another way of the photoacoustic method, called phase-domain photoacoustic sensing, which explores the phase difference between two consequent intensity-modulated laser pulse induced photoacoustic measurements to reveal the optical properties. The basic principle is introduced, modeled, and experimentally validated in this paper, which opens another potential pathway to perform photoacoustic sensing and imaging, eliminating acoustic detection variations beyond the conventional time-domain and frequency-domain photoacoustic methods.
Singular Integrals with Bilinear Phases
Institute of Scientific and Technical Information of China (English)
Elena PRESTINI
2006-01-01
We prove the boundedness from Lp(T2) to itself, 1 ＜ p ＜∞, of highly oscillatory singular integrals Sf(x, y) presenting singularities of the kind of the double Hilbert transform on a non-rectangular domain of integration, roughly speaking, defined by |y′| ＞ | x′|, and presenting phases λ(Ax + By) with 0 ≤ A, B ≤ 1 and λ≥ 0. The norms of these oscillatory singular integrals are proved to be independent of all parameters A, B and λ involved. Our method extends to a more general family of phases. These results are relevant to problems of almost everywhere convergence of double Fourier and Walsh series.
Chaotic eigenfunctions in phase space
Nonnenmacher, S
1997-01-01
We study individual eigenstates of quantized area-preserving maps on the 2-torus which are classically chaotic. In order to analyze their semiclassical behavior, we use the Bargmann-Husimi representations for quantum states, as well as their stellar parametrization, which encodes states through a minimal set of points in phase space (the constellation of zeros of the Husimi density). We rigorously prove that a semiclassical uniform distribution of Husimi densities on the torus entails a similar equidistribution for the corresponding constellations. We deduce from this property a universal behavior for the phase patterns of chaotic Bargmann eigenfunctions, which reminds of the WKB approximation for eigenstates of integrable systems (though in a weaker sense). In order to obtain more precise information on ``chaotic eigenconstellations", we then model their properties by ensembles of random states, generalizing former results on the 2-sphere to the torus geometry. This approach yields statistical predictions fo...
Phase space embedding of electrocardiograms
Richter, M; Richter, Marcus; Schreiber, Thomas
1998-01-01
We study properties of the human electrocardiogram under the working hypothesis that fluctuations beyond the regular structure of single cardiac cycles are unpredictable. On this background we discuss the possibility to use the phase space embedding method for this kind of signal. In particular, the specific nature of the stochastic or high dimensional component allows to use phase space embeddings for certain signal processing tasks. As practical applications, we discuss noise filtering, fetal ECG extraction, and the automatic detection of clinically relevant features. The main purpose of the paper is to connect results of embedding theory which had not been previously applied in practise, and practical applications which had not yet been justified theoretically.
Moment Distributions of Phase Type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
-type distributions. We construct representations for moment distributions based on a general matrix-exponential distribution which turns out to be a generalization of the moment distributions based on exponential distributions. For moment distributions based on phase{type distributions we find an appropriate...... alternative representation in terms of sub{intensity matrices. Finally we are able to nd explicit expressions for both the Lorenz curve and the Gini index....
Tent Shaped Phased Array Tests.
1982-01-01
AD-A113 191 HARRIS CORP MELBOURNE FL GOVERNMENT COMMUNICATION SY-ETC Fi 20/11TENT SHAPED PHASED ARRAY TESTS.(U JAN 82 C A CHUANG F19628-79-C-T173...821714f1 45 0 +450 SCAN PLANE ARRAY PATTERNS FIG. B-31 B- 31 AD-AL13 191 HARRS CRP PMELBOURNE FLY GOVERNMENT COMMUNICATION ST--ETC F/6 20/14 TENT SHAPED
SOLID PHASE SYNTHESIS OF ISOXAZOLINES
Institute of Scientific and Technical Information of China (English)
SUNWeimin; LUOJuntao; 等
2002-01-01
The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin is reported.2-Polystyrylsulfonamidoethanol resin 1 was reacted with acryloyl chloride to afford 2-polystyrylsulfonylamidoethyl acrylate resin 2,which was further reacted with brominated aldoximes by [3+2] cycloaddition to give isoxazoline resin 4.Resin 4 was treated with aqueous 6 mol/L HCl solution to obtain isoxazolines in good yield and purity.
Quantum gates with topological phases
Ionicioiu, R
2003-01-01
We investigate two models for performing topological quantum gates with the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects. Topological one- and two-qubit Abelian phases can be enacted with the AB effect using charge qubits, whereas the AC effect can be used to perform all single-qubit gates (Abelian and non-Abelian) for spin qubits. Possible experimental setups suitable for a solid state implementation are briefly discussed.
DESIGN THREE PHASE OVERCURRENT RELAYS
Directory of Open Access Journals (Sweden)
Mohammed Y Suliman,
2013-05-01
Full Text Available A new design of three phase overcurrent relay described in this paper. The performance of the new design shows the ability to obtain any shape of characteristic with high accuracy and distinguish between transient and steady state fault. This design used more precise and flexible model Sachdev linear model for get any characteristic, also fast measurement theory to measure load current for less than half cycle and good hardware system design controlled by Pentium version 4 processor.
Final Report: Sensorpedia Phase 3
Energy Technology Data Exchange (ETDEWEB)
Gorman, Bryan L [ORNL; Resseguie, David R [ORNL
2011-02-01
This report is a summary of the Oak Ridge National Laboratory s (ORNL s) Phase 3 development of Sensorpedia, a sensor information sharing platform. Sensorpedia is ORNL s Wikipedia for Sensors. The overall goal of Sensorpedia is to enable global scale sensor information sharing for scientific research, national security and defense, public health and safety, emergency preparedness and response, and general community awareness and outreach.
Quantum Shuttle in Phase Space
DEFF Research Database (Denmark)
Novotny, Tomas; Donarini, Andrea; Jauho, Antti-Pekka
2003-01-01
Abstract: We present a quantum theory of the shuttle instability in electronic transport through a nanostructure with a mechanical degree of freedom. A phase space formulation in terms of the Wigner function allows us to identify a crossover from the tunneling to the shuttling regime, thus...... extending the previously found classical results to the quantum domain. Further, a new dynamical regime is discovered, where the shuttling is driven exclusively by the quantum noise....
QCD Phase Transitions, Volume 15
Energy Technology Data Exchange (ETDEWEB)
Schaefer, T.; Shuryak, E.
1999-03-20
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.
Katarina Anthony
2012-01-01
The newest phase of CERN’s openlab framework was inaugurated this week during a meeting of the openlab partners. This phase will last three years and will bring together existing openlab partners and a new contributor: Huawei. Group picture taken at the first CERN openlab IV annual Board of Sponsors meeting, in the presence of the CERN Director-General, the partners and the openlab team members. © Fons Rademakers (CERN Photo Club). Eleven years ago, the creation of the CERN openlab created a long-term link between industrial partners and the Organization. Its framework has allowed industry to carry out large-scale IT research and development in an open atmosphere – an “Open Lab”, if you will. For CERN, openlab has contributed to giving the computing centre and, more broadly, the LHC community, the opportunity to ensure that the next generation of services and products is suitable to their needs. Now entering its fourth phase, openlab will ...
Phase diagram of crushed powders
Bodard, Sébastien; Jalbaud, Olivier; Saurel, Richard; Burtschell, Yves; Lapebie, Emmanuel
2016-12-01
Compression of monodisperse powder samples in quasistatic conditions is addressed in a pressure range such that particles fragmentation occurs while the solid remains incompressible (typical pressure range of 1-300 MPa for glass powders). For a granular bed made of particles of given size, the existence of three stages is observed during compression and crush up. First, classical compression occurs and the pressure of the granular bed increases along a characteristic curve as the volume decreases. Then, a critical pressure is reached for which fragmentation begins. During the fragmentation process, the granular pressure stays constant in a given volume range. At the end of this second stage, 20%-50% of initial grains are reduced to finer particles, depending on the initial size. Then the compression undergoes the third stage and the pressure increases along another characteristic curve, in the absence of extra fragmentation. The present paper analyses the analogies between the phase transition in liquid-vapour systems and powder compression with crush-up. Fragmentation diagram for a soda lime glass is determined by experimental means. The analogues of the saturation pressure and latent heat of phase change are determined. Two thermodynamic models are then examined to represent the crush-up diagram. The first one uses piecewise functions while the second one is of van der Waals type. Both equations of state relate granular pressure, solid volume fraction, and initial particle diameter. The piecewise functions approach provides reasonable representations of the phase diagram while the van der Waals one fails.
NIF optics phase gradient specfication
Energy Technology Data Exchange (ETDEWEB)
Williams, W.; Auerbach, J.; Hunt, J.; Lawson, L.; Manes, K.; Orth, C.; Sacks, R.; Trenholme, J.; Wegner, P.
1997-05-02
A root-mean-square (rms) phase gradient specification seems to allow a good connection between the NIP optics quality and focal spot requirements. Measurements on Beamlet optics individually, and as a chain, indicate they meet the assumptions necessary to use this specification, and that they have a typical rms phase gradient of {approximately}80 {angstrom}/cm. This may be sufficient for NIP to meet the proposed Stockpile Stewardship Management Program (SSMP) requirements of 80% of a high- power beam within a 200-250 micron diameter spot. Uncertainties include, especially, the scale length of the optics phase noise, the ability of the adaptive optic to correct against pump-induced distortions and optics noise, and the possibility of finding mitigation techniques against whole-beam self-focusing (e.g. a pre- correction optic). Further work is needed in these areas to better determine the NIF specifications. This memo is a written summary of a presentation on this topic given by W. Williams 24 April 1997 to NIP and LS&T personnel.
Energy Technology Data Exchange (ETDEWEB)
Parker, E.N. [Univ. of Chicago, IL (United States)
1994-10-01
Space science began with the indirect phase where the activity in space was inferred from such terrestrial phenomena as geomagnetic storms, ionospheric variations, and fluctuations in the cosmic ray intensity. The direct phase was initiated with spaceflight placing instruments directly in space and permitting the direct observation of UV and X rays, as well as precision observations of solar luminosity variations. The evidence from these many direct studies, together with the historical record of terrestrial conditions, shows that the variations of the luminosity of the Sun affect the terrestrial atmosphere at all levels, with devastating changes in climate tracking the major changes in the activity level and luminosity of the Sun. The quantification and understanding of this vital connection should be the first priority of space science and geophysics, from oceans and atmosphere through the ionosphere, magnetosphere, and all the way to the convective zone of the Sun. It becomes the vital phase of space science, focused on the basic science of the changing habitability of Earth. 13 refs.
Phase-preserved optical elevator
Luo, Yuan; Zhang, Baile; Han, Tiancheng; Chen, Zhi; Duan, Yubo; Chu, Chia-Wei; Barbastathis, George; Qiu, Cheng Wei
2013-01-01
The unique superiority of transformation optics devices designed from coordinate transformation is their capability of recovering both ray trajectory and optical path length in light manipulation. However, very few experiments have been done so far to verify this dual-recovery property from viewpoints of both ray trajectory and optical path length simultaneously. The experimental difficulties arise from the fact that most previous optical transformation optics devices only work at the nano-scale; the lack of intercomparison between data from both optical path length and ray trajectory measurement in these experiments obscured the fact that the ray path was subject to a subwavelength lateral shift that was otherwise not easily perceivable and, instead, was pointed out theoretically [B. Zhang et al. Phys. Rev. Lett. 104, 233903, (2010)]. Here, we use a simple macroscopic transformation optics device of phase-preserved optical elevator, which is a typical birefringent optical phenomenon that can virtually lift an optical image by a macroscopic distance, to demonstrate decisively the unique optical path length preservation property of transformation optics. The recovery of ray trajectory is first determined with no lateral shift in the reflected ray. The phase preservation is then verified with incoherent white-light interferometry without ambiguity and phase unwrapping. PMID:23546046
Phase diagram of elastic spheres.
Athanasopoulou, L; Ziherl, P
2017-02-15
Experiments show that polymeric nanoparticles often self-assemble into several non-close-packed lattices in addition to the face-centered cubic lattice. Here, we explore theoretically the possibility that the observed phase sequences may be associated with the softness of the particles, which are modeled as elastic spheres interacting upon contact. The spheres are described by two finite-deformation theories of elasticity, the modified Saint-Venant-Kirchhoff model and the neo-Hookean model. We determine the range of indentations where the repulsion between the spheres is pairwise additive and agrees with the Hertz theory. By computing the elastic energies of nine trial crystal lattices at densities far beyond the Hertzian range, we construct the phase diagram and find the face- and body-centered cubic lattices as well as the A15 lattice and the simple hexagonal lattice, with the last two being stable at large densities where the spheres are completely faceted. These results are qualitatively consistent with observations, suggesting that deformability may indeed be viewed as a generic property that determines the phase behavior in nanocolloidal suspensions.
Motility-Induced Phase Separation
Cates, Michael E.; Tailleur, Julien
2015-03-01
Self-propelled particles include both self-phoretic synthetic colloids and various microorganisms. By continually consuming energy, they bypass the laws of equilibrium thermodynamics. These laws enforce the Boltzmann distribution in thermal equilibrium: The steady state is then independent of kinetic parameters. In contrast, self-propelled particles tend to accumulate where they move more slowly. They may also slow down at high density for either biochemical or steric reasons. This creates positive feedback, which can lead to motility-induced phase separation (MIPS) between dense and dilute fluid phases. At leading order in gradients, a mapping relates variable-speed, self-propelled particles to passive particles with attractions. This deep link to equilibrium phase separation is confirmed by simulations but generally breaks down at higher order in gradients: New effects, with no equilibrium counterpart, then emerge. We give a selective overview of the fast-developing field of MIPS, focusing on theory and simulation but including a brief speculative survey of its experimental implications.
Simultaneous amplitude and phase modulation by a discrete phase-only filter.
Goto, Hiroomi; Konishi, Tsuyoshi; Itoh, Kazuyoshi
2009-03-01
We propose a simultaneous amplitude and phase modulation method by a discrete phase-only filter. The proposed amplitude-phase filter can be realized by a discrete phase modulation of the diffractive optical element as well as a continuous phase modulation of the liquid crystal spatial light modulator. The fabricated amplitude-phase filter that has the six phase modulation levels shows a transfer efficiency of 75% regardless of the polarization state of the incident light. By using the proposed amplitude-phase filter, we demonstrate a temporal waveform conversion from sech(2) to super-Gaussian, which requires both amplitude and phase modulations.
Thermophysical properties of coexistent phases of plutonium
Energy Technology Data Exchange (ETDEWEB)
Freibert, Franz J [Los Alamos National Laboratory; Mitchell, Jeremy N [Los Alamos National Laboratory; Saleh, Tarik A [Los Alamos National Laboratory; Schwartz, Dan S [Los Alamos National Laboratory
2009-01-01
Plutonium is the element with the greatest number of allotropic phases. Thermally induced transformations between these phases are typically characterized by thermal hysteresis and incomplete phase reversion. With Ga substitutal in the lattice, low symmetry phases are replaced by a higher symmetry phase. However, the low temperature Martensitic phase transformation ({delta} {yields} {alpha}{prime}) in Ga stabilized {delta}-phase Pu is characterized by a region of thermal hysteresis which can reach 200 C in extent. These regions of thermal hysteresis offer a unique opportunity to study thermodynamics in inhomogeneous systems of coexistent phases. The results of thermophysical properties measured for samples of inhomogeneous unalloyed and Ga alloyed Pu will be discussed and compared with similar measurements of their single phase constituents.
Thermophysical properties of coexistent phases of plutonium
Energy Technology Data Exchange (ETDEWEB)
Freibert, F J; Mitchell, J N; Saleh, T A; Schwartz, D S, E-mail: freibert@lanl.gov, E-mail: jeremy@lanl.gov, E-mail: tsaleh@lanl.gov, E-mail: dschwartz@lanl.gov [Nuclear Materials Science Group, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2010-03-15
Plutonium is the element with the greatest number of allotropic phases. Thermally induced transformations between these phases are typically characterized by thermal hysteresis and incomplete phase reversion. With Ga substitutional in the lattice, low symmetry phases are replaced by a higher symmetry phase. However, the low temperature martensitic phase transformation ({delta}{yields}{alpha}') in Ga stabilized {delta}-phase Pu is characterized by a region of thermal hysteresis which can reach 200 deg. C in extent. These regions of thermal hysteresis offer a unique opportunity to study thermodynamics in inhomogeneous systems of coexistent phases. The results of thermophysical properties measured for samples of inhomogeneous unalloyed and Ga alloyed Pu will be discussed and compared with similar measurements of their single phase constituents.
Two-phase flow research. Phase 1: Two-phase nozzle research
Toner, S. J.
1981-07-01
Experimental performance of converging-diverging nozzles operating on air-water mixtures is presented for a wide range of parameters. Thrust measurements characterized the performance and photographic documentation was used to visually observe the off-design regimes. Thirty-six nozzle configurations were tested to determine the effects of convergence angle, area ratio, and nozzle length. In addition, the pressure ratio and mass flowrate ratio were varied to experimentally map off-design performance. The test results indicate the effects of wall friction and infer temperature and velocity differences between phases and the effect on nozzle performance. The slip ratio between the phases, gas velocity to liquid velocity, is shown to be below about 4 or 5.
Spiral phase contrast imaging in microscopy.
Fürhapter, Severin; Jesacher, Alexander; Bernet, Stefan; Ritsch-Marte, Monika
2005-02-07
We demonstrate an optical method for edge contrast enhancement in light microscopy. The method is based on holographic Fourier plane filtering of the microscopic image with a spiral phase element (also called vortex phase or helical phase filter) displayed as an off-axis hologram at a computer controlled high resolution spatial light modulator (SLM) in the optical imaging pathway. The phase hologram imprints a helical phase term of the form exp(i phi) on the diffracted light field in its Fourier plane. In the image plane, this results in a strong and isotropic edge contrast enhancement for both amplitude and phase objects.
Discrete continuous-phase superresolving filters.
Zhou, Sumei; Zhou, Changhe
2004-12-01
A new type of phase-only superresolving pupil filter with a discrete continuous-phase profile is presented that is a combination of discrete multilevel-phase modulation and continuous-phase modulation. This type of filter can achieve better superresolution performance than the continuous-phase filters reported in Opt. Lett. 28, 607 (2003). Therefore, with regard to the superresolution effect, this type of filter deserves study for practical applications. More importantly, the diffraction performance of this type of filter can explain the effect of a discrete-phase filter illuminated with a continuous wave front, whose superresolving performance cannot be analyzed with previous superresolution methods.
Phases definition in marketing export process
Directory of Open Access Journals (Sweden)
Rajković Dragan
2004-01-01
Full Text Available The result of export marketing process depends on its five phases. The first phase-revision of export capacities, inner view on advantages and defects of company concerning export possibilities. The second phase-identification of export strategy market penetration. The forth phase-preparing for the marketing campaign (action. The fifth phase-carrying out the above mentioned activities. This study shows the structure and contents of the mentioned phases. At the end, export marketing analyzed DPV is given as the example.
Viscoelastic Phase Separation of Protein Solutions
Tanaka, Hajime; Nishikawa, Yuya
2005-08-01
In addition to the known behavior of normal phase separation and gelation, we report novel phase-separation behavior of protein solutions as their intermediate case. A network structure of the protein-rich phase may be formed even if it is the minority phase, contrary to the conventional wisdom. This behavior is characteristic of viscoelastic phase separation found in polymer solutions. This kinetic pathway may play crucial roles in the complex phase ordering of protein solutions, in particular, protein network formation in biological systems and foods.
Quark Deconfinement Phase Transition in Neutron Stars
Alaverdyan, G B
2009-01-01
The hadron-quark phase transition in the interior of compact stars is investigated, when the transition proceeds through a mixed phase. The hadronic phase is described in the framework of relativistic mean-field theory, when also the scalar-isovector delta-meson mean-field is taken into account. The changes of the parameters of phase transition caused by the presence of delta-meson field are explored. The results of calculation of structure of the mixed phase (Glendenning construction) are compared with the results of usual first-order phase transition (Maxwell construction).
Phase-locked laser coherent interference
Institute of Scientific and Technical Information of China (English)
Jingjing Wang; Xiaobo Wang; Bo He; Liantuan Mao; Suotang Jia
2011-01-01
A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated. It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system. After phase locking using the phase modulating and lock-in technique, the drift of the relative phase is focalized around ±0.0016 rad and the fringe visibility is restricted to 2×l0-4.%@@ A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated.It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system.After phase locking using the vhase modulating and lock-in technique.the drift of the relative phase is focalized around±0.0016 rad and the fringe visibility is restricted to 2×10-4.
A novel three-phase UPS system with a single-phase resonant HF link
Darwish, MK
2006-01-01
This paper presents a new three-phase uninterruptible power supply (UPS) system based on a single-phase resonant high frequency (HF) link and a single-phase transformer. The three-phase output voltage is constructed and regulated from a three-phase cycloconverter fed from the constant amplitude, constant frequency link voltage. The generation of a novel switching stategy for the three-phase cycloconverter is presented. The simulation of the proposed system is carried out and verified with exp...
Passive longitudinal phase space linearizer
Directory of Open Access Journals (Sweden)
P. Craievich
2010-03-01
Full Text Available We report on the possibility to passively linearize the bunch compression process in electron linacs for the next generation x-ray free electron lasers. This can be done by using the monopole wakefields in a dielectric-lined waveguide. The optimum longitudinal voltage loss over the length of the bunch is calculated in order to compensate both the second-order rf time curvature and the second-order momentum compaction terms. Thus, the longitudinal phase space after the compression process is linearized up to a fourth-order term introduced by the convolution between the bunch and the monopole wake function.
Phase transitions and critical phenomena
Domb, Cyril
2001-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies.Statistical physics, and more specifically, the theory of transitions between states of matter, more or less defines what we know about 'everyday' matter and its transformations.The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable in
Airborne electronically steerable phased array
1972-01-01
The results are presented of the second stage of a program for the design and development of a phased array capable of simultaneous and separate transmission and reception of radio frequency signals at S-band frequencies. The design goals of this stage were the development of three major areas of interest required for the final prototype model. These areas are the construction and testing of the low-weight, full-scale 128-element array of antenna elements, the development of the RF manifold feed system, and the construction and testing of a working module containing diplexer and transmit and receive circuits.
Waveguide mutually pumped phase conjugators
James, S. W.; Youden, K.E.; Jeffrey, P. M.; EASON, R. W.; Chandler, P.J.; Zhang, L.; Townsend, P.D.
1993-01-01
The operation of the Bridge Mutually Pumped Phase Conjugator is reported in a planar waveguide structure in photorefractive BaTiO3. The waveguide was fabricated by the technique of ion implantation. using 1.5 MeV H+ at a dose of 10^16 ions/cm^2. An order of magnitude decrease in response time is observed in the waveguide as compared to typical values obtained in bulk crystals, probably resulting from a combination of the optical confinement within the waveguide, and possibly modification of t...
DEFF Research Database (Denmark)
Thomsen, P.E.B.; Jørgensen, R.M.; Kanters, J.K.;
2005-01-01
mu V, range 0-1,700) and T-wave changes in the sinus beat prior to ventricular ectopy. In addition, J-point elevation was demonstrated in several cases. In total, significant changes were demonstrated in 15 of the 18 patients studied (83%). CONCLUSION J-point elevation, ST-elevation, and T......-wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments...
Phase Transition in Tensor Models
Delepouve, Thibault
2015-01-01
Generalizing matrix models, tensor models generate dynamical triangulations in any dimension and support a $1/N$ expansion. Using the intermediate field representation we explicitly rewrite a quartic tensor model as a field theory for a fluctuation field around a vacuum state corresponding to the resummation of the entire leading order in $1/N$ (a resummation of the melonic family). We then prove that the critical regime in which the continuum limit in the sense of dynamical triangulations is reached is precisely a phase transition in the field theory sense for the fluctuation field.
Experimental Blade Research - phase 2
Eder, Martin Alexander; Branner, Kim; Berring, Peter; Belloni, Federico; Stensgaard Toft, Henrik; Sørensen, John Dalsgaard; Corre, Adrien; Lindby, Torben; Quispitupa, Amilcar; Petersen, Thomas Karl
2015-01-01
This report is a summary of the results obtained in the project: Experimental Blade Research – phase 2 (EBR2). The project was supported by the Danish Energy Authority through the 2010 Energy Technology Development and Demonstration Program (EUDP 2010-II) and has journal no. 64011-0006. The project has been running from spring 2011 to the end of 2014.Being a summary report, this report only contains a collection of the research topics and the major results. For more details, see the publicati...
Gibbs measures and phase transitions
Georgii, Hans-Otto
2011-01-01
From a review of the first edition: ""This book […] covers in depth a broad range of topics in the mathematical theory of phase transition in statistical mechanics. […] It is in fact one of the author's stated aims that this comprehensive monograph should serve both as an introductory text and as a reference for the expert."" (F. Papangelou, Zentralblatt MATH) The second edition has been extended by a new section on large deviations and some comments on the more recent developments in the area.
Workman, Gary L.; Smith, Guy A.
1997-01-01
A Phase B feasibility study will be performed for the study of the effects of microgravity on the preform processing and fiber pulling of ZBLAN optical glass. Continuing from the positive results achieved in the fiber annealing experiments in 20 second intervals at 0.001 g on the KC-135 and the 5 minute experiments on the SPAR rocket, experiments will continue to work towards design of a fiber sting to initiate fiber pulling operations in space. Anticipated results include less homogeneous nucleation than ground-based annealed fibers. Infrared Fiber Systems and Galileo are the participating industrial investigators.
Light scattering near phase transitions
Cummins, HZ
1983-01-01
Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.
Phase Change Fabrics Control Temperature
2009-01-01
Originally featured in Spinoff in 1997, Outlast Technologies Inc. (formerly Gateway Technologies Inc.) has built its entire product line on microencapsulated phase change materials, developed in Small Business Innovation Research (SBIR) contracts with Johnson Space Center after initial development for the U.S. Air Force. The Boulder, Colorado-based company acquired the exclusive patent rights and now integrates these materials into textiles or onto finished apparel, providing temperature regulation in bedding materials and a full line of apparel for both ordinary and extreme conditions.
Phase transitions and critical phenomena
Domb, Cyril
2000-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what m
Phase sorting wave-particle correlator
Kletzing, C. A.; LaBelle, J.; Bounds, S. R.; Dolan, J.; Kaeppler, S. R.; Dombrowski, M.
2017-02-01
Wave-particle correlations, particularly of Langmuir waves and electrons, have been the subject of significant interest extending back to the 1970s. Often, these correlations have been simply observing modulation of the electrons at the plasma frequency with no phase resolution. The first phase-resolving correlators were developed at UC Berkeley in the late 1980s and reported by Ergun in the early 1990s. A design is presented which further improves on phase resolution in correlations of Langmuir waves and electrons with phase resolution of 22.5°. In this technique, a phase-locked loop (PLL) is used to lock onto the wave and subdivide the phase. Electrons are sorted on-the-fly as they arrive into the phase bins. Discussed are details of accurate timing, testing, and calibration of this system as well as results from rocket flights in which statistically significant phase correlations have been observed.
Phases of holographic d-wave superconductor
Krikun, Alexander
2015-01-01
We study different phases in the holographic model of d-wave superconductor. These are described by solutions to the classical equations of motion found in different ansatze. Apart from the known homogeneous d-wave superconducting phase we find three new solutions. Two of them represent two distinct families of the spatially modulated solutions, which realize the charge density wave phases in the dual theory. The third one is the new homogeneous phase with nonzero anapole moment. These phases are relevant to the physics of cuprate high-Tc superconductor in pseudogap region. While the d-wave phase preserves translation, parity and time reversal symmetry, the striped phases break translations spontaneously. Parity and time-reversal are preserved when combined with discrete half-periodic shift of the wave. In anapole phase translation symmetry is preserved, but parity and time reversal are spontaneously broken. All of the considered solutions brake the global $U(1)$. Thermodynamical treatment shows that in the s...
Complex phase dynamics in coupled bursters
DEFF Research Database (Denmark)
Postnov, D.E.; Sosnovtseva, Olga; Malova, S.Y.;
2003-01-01
The phenomenon of phase multistability in the synchronization of two coupled oscillatory systems typically arises when the systems individually display complex wave forms associated, for instance, with the presence of subharmonic components. Alternatively, phase multistability can be caused...
Phase Multistability in Coupled Oscillator Systems
DEFF Research Database (Denmark)
Mosekilde, Erik; Postnov, D.E.; Sosnovtseva, Olga
2003-01-01
The phenomenon of phase multistability arises in connection with the synchronization of coupled oscillator systems when the systems individually display complex wave forms associated, for instance, with the presence of subharmonic components or with significant variations of the phase velocity...
Low Cost Phased Array Antenna System Project
National Aeronautics and Space Administration — JEM Engineering proved the technical feasibility of the FlexScan array?a very low-cost, highly-efficient, wideband phased array antenna?in Phase I, and stands ready...
Phase transformations during the growth of paracetamol crystals from the vapor phase
Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.; Bordei, N. S.
2014-07-01
Phase transformations during the growth of paracetamol crystals from the vapor phase are studied by differential scanning calorimetry. It is found that the vapor-crystal phase transition is actually a superposition of two phase transitions: a first-order phase transition with variable density and a second-order phase transition with variable ordering. The latter, being a diffuse phase transition, results in the formation of a new, "pretransition," phase irreversibly spent in the course of the transition, which ends in the appearance of orthorhombic crystals. X-ray diffraction data and micrograph are presented.
Low Pass Filters with Linear Phase.
1985-12-12
DISCUSSION OF RESULTS............................... 35 LIST OF ILLUSTRATIONS Figure page 1. Template applicable to single stage linear phase filter .................. 2...technology suggests examination of the low-pass lin- ear phase filter as a means of prefiltering such data before, or concurrently with, sam- pling. Today, a...stage low passlinear phase filter . Here, M is the number of "main poles". A linear phase design alsorequires a minimum overhead of two "corrector poles
Phase equilibria basic principles, applications, experimental techniques
Reisman, Arnold
2013-01-01
Phase Equilibria: Basic Principles, Applications, Experimental Techniques presents an analytical treatment in the study of the theories and principles of phase equilibria. The book is organized to afford a deep and thorough understanding of such subjects as the method of species model systems; condensed phase-vapor phase equilibria and vapor transport reactions; zone refining techniques; and nonstoichiometry. Physicists, physical chemists, engineers, and materials scientists will find the book a good reference material.
Insights on some chiral smectic phases
Indian Academy of Sciences (India)
B Pansu
2003-08-01
Combining layered positional order as smectic order and chirality can generate complex architectures since twist parallel to the layers is not allowed. This paper will review some new experimental results on different phases resulting from the competition between smectic positional order and twist orientational order. It concerns the TGBA and the NL*, that is the liquid line phase as well as the SmQ phase. Chiral effects in the isotropic phase will also be discussed.
QCD Phase Diagram with Imaginary Chemical Potential
Directory of Open Access Journals (Sweden)
Nakamura Atsushi
2012-02-01
Full Text Available We report our recent results on the QCD phase diagram obtained from the lattice QCD simulation. The location of the phase boundary between hadronic and QGP phases in the two-flavor QCD phase diagram is investigated. The imaginary chemical potential approach is employed, which is based on Monte Carlo simulations of the QCD with imaginary chemical potential and analytic continuation to the real chemical potential region.
Signature of Topological Phases in Zitterbewegung
Ghosh, S.
2016-09-02
We have studied the Zitterbewegung effect on an infinite two-dimensional sheet with honeycomb lattice. By tuning the perpendicular electric field and the magnetization of the sheet, it can enter different topological phases. We have shown that the phase and magnitude of Zitterbewegung effect, i.e., the jittering motion of electron wavepackets, correlates with the various topological phases. The topological phase diagram can be reconstructed by analyzing these features. Our findings are applicable to materials like silicene, germanene, stanene, etc.
Solid phase syntheses of oligoureas
Energy Technology Data Exchange (ETDEWEB)
Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)
1997-02-19
Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.
SARCOPENIA: DESIGNING PHASE IIB TRIALS
CHUMLEA, WM.C.; CESARI, M.; EVANS, W.J.; FERRUCCI, L.; FIELDING, R.A.; PAHOR, M.; STUDENSKI, S.; VELLAS, B.
2012-01-01
Sarcopenia is the age-related involuntary loss of skeletal muscle mass and functionality that can lead to the development of disability, frailty and increased health care costs. The development of interventions aimed at preventing and/or treating sarcopenia is complex, requiring the adoption of assumptions and standards that are not well established scientifically or clinically. A number of investigators and clinicians (both from academia and industry) met in Rome (Italy) in 2009 to develop a consensus definition of sarcopenia. Subsequently, in Albuquerque (New Mexico, USA) in 2010, the same group met again to consider the complex issues necessary for designing Phase II clinical trials for sarcopenia. Current clinical trial data indicate that fat-free mass (FFM) parameters are responsive to physical activity/nutritional treatment modalities over short time periods, but pharmacological trials of sarcopenia have yet to show significant efficacy. In order to conduct a clinical trial within a reasonable time frame, groups that model or display accelerated aging and loss of FFM are necessary. Few studies have used acceptable designs for testing treatment effects, sample sizes or primary outcomes that could provide interpretable findings or effects across studies. Dual energy x ray absorptiometry (DXA) is the measure of choice for assessing FFM, but sufficient time is needed for changes to be detected accurately and reliably. A tool set that would allow clinical, basic and epidemiological research on sarcopenia to advance rapidly toward diagnosis and treatment phases should be those reflecting function and strength. PMID:21623466
Availability program: Phase I report
Energy Technology Data Exchange (ETDEWEB)
Thomson, S.L.; Dabiri, A.; Keeton, D.C.; Riemer, B.W.; Waganer, L.M.
1985-05-01
An Availability Working Group was formed within the Office of Fusion Energy in March 1984 to consider the establishment of an availability program for magnetic fusion. The scope of this program is defined to include the development of (1) a comprehensive data base, (2) empirical correlations, and (3) analytical methods for application to fusion facilities and devices. The long-term goal of the availability program is to develop a validated, integrated methodology that will provide (1) projections of plant availability and (2) input to design decisions on maintainability and system reliability requirements. The Phase I study group was commissioned to assess the status of work in progress that is relevant to the availability program. The scope of Phase I included surveys of existing data and data collection programs at operating fusion research facilities, the assessment of existing computer models to calculate system availability, and the review of methods to predict and correlate data on component failure and maintenance. The results of these investigations are reported to the Availability Working Group in this document.
Arrested segregative phase separation in capillary tubes
Tromp, R. Hans; Lindhoud, Saskia
2006-01-01
Phase separation in a capillary tube with one of the phases fully wetting the capillary wall is arrested when the typical size of the phase domains reaches the value of the diameter of the tube. The arrested state consists of an alternating sequence of concave-capped and convex-capped cylindrical
A general formalism for phase space calculations
Norbury, John W.; Deutchman, Philip A.; Townsend, Lawrence W.; Cucinotta, Francis A.
1988-01-01
General formulas for calculating the interactions of galactic cosmic rays with target nuclei are presented. Methods for calculating the appropriate normalization volume elements and phase space factors are presented. Particular emphasis is placed on obtaining correct phase space factors for 2-, and 3-body final states. Calculations for both Lorentz-invariant and noninvariant phase space are presented.
Centrifuge workers study. Phase II, completion report
Energy Technology Data Exchange (ETDEWEB)
Wooten, H.D.
1994-09-01
Phase II of the Centrifuge Workers Study was a follow-up to the Phase I efforts. The Phase I results had indicated a higher risk than expected among centrifuge workers for developing bladder cancer when compared with the risk in the general population for developing this same type of cancer. However, no specific agent could be identified as the causative agent for these bladder cancers. As the Phase II Report states, Phase I had been limited to workers who had the greatest potential for exposure to substances used in the centrifuge process. Phase II was designed to expand the survey to evaluate the health of all employees who had ever worked in Centrifuge Program Departments 1330-1339 but who had not been interviewed in Phase I. Employees in analytical laboratories and maintenance departments who provided support services for the Centrifuge Program were also included in Phase II. In December 1989, the Oak Ridge Associated Universities (ORAU), now known as Oak Ridge Institute for Science and Education (ORISE), was contracted to conduct a follow-up study (Phase II). Phase H of the Centrifuge Workers Study expanded the survey to include all former centrifuge workers who were not included in Phase I. ORISE was chosen because they had performed the Phase I tasks and summarized the corresponding survey data therefrom.
From ergodicity to extended phase diagrams.
Woodley, Scott M; Sokol, Alexey A
2012-04-16
Structure prediction of stable and metastable phases is put on equal footing for the first time, with a solid thermodynamical background. How to estimate the lifetime of metastable phases is demonstrated by recent groundbreaking work of Jansen, Pentin, and Schön. At the heart lies the exploration of the Gibbs free-energy landscapes and the extended phase diagrams for complex systems.
Phase transformation at Lilliput; Changement de phase a Lilliput
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph
2001-07-01
Recent theoretical development show that during phase transformations, occurring in a small system, heat capacity can become negative momentarily. This phenomenon can be explained easily: when you want to create a bubble of gas in a liquid or a drop of liquid in a gas you have to pay the price of the interface, it means that you have to provide the system with the surface energy of the bubble or of the drop. This energy need is made at the expense of the thermal motion and in a small system this contribution is not negligible and implies a decrease in temperature. Recently negative values of heat capacity have been reported in multi-fragmentation nuclear reactions, the author presents experimental data in gold and xenon collisions with respectively gold and tin targets. (A.C.)
Symmetric Topological Phases and Tensor Network States
Jiang, Shenghan
Classification and simulation of quantum phases are one of main themes in condensed matter physics. Quantum phases can be distinguished by their symmetrical and topological properties. The interplay between symmetry and topology in condensed matter physics often leads to exotic quantum phases and rich phase diagrams. Famous examples include quantum Hall phases, spin liquids and topological insulators. In this thesis, I present our works toward a more systematically understanding of symmetric topological quantum phases in bosonic systems. In the absence of global symmetries, gapped quantum phases are characterized by topological orders. Topological orders in 2+1D are well studied, while a systematically understanding of topological orders in 3+1D is still lacking. By studying a family of exact solvable models, we find at least some topological orders in 3+1D can be distinguished by braiding phases of loop excitations. In the presence of both global symmetries and topological orders, the interplay between them leads to new phases termed as symmetry enriched topological (SET) phases. We develop a framework to classify a large class of SET phases using tensor networks. For each tensor class, we can write down generic variational wavefunctions. We apply our method to study gapped spin liquids on the kagome lattice, which can be viewed as SET phases of on-site symmetries as well as lattice symmetries. In the absence of topological order, symmetry could protect different topological phases, which are often referred to as symmetry protected topological (SPT) phases. We present systematic constructions of tensor network wavefunctions for bosonic symmetry protected topological (SPT) phases respecting both onsite and spatial symmetries.
Phase separation in an ionomer glass
DEFF Research Database (Denmark)
Pedersen, Malene Thostrup; Tian, K.V.; Dobó-Nagy, C.
2015-01-01
conclusively determined. In this work, we identify these phases by performing differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses on both the as-received glass and heat-treated samples. We detected three glass transitions in the as-received G338 glass during DSC upscaning, implying...... amorphous phases in G388 are Ca/Na-Al-Si-O, Ca-Al-F and Ca-P-O-F phases, respectively. However, the exact chemical compositions of the three phases still require further exploration. The results of this work are important for understanding the impact of phase separation within ionomer glasses on the setting...
Magnetic phase diagram of Ho-Ag
Energy Technology Data Exchange (ETDEWEB)
Paul-Boncour, V [Chimie Metallurgique des Terres Rares, ICMPE, CNRS, 2 rue H Dunant, 94320 Thiais (France); Hoser, A; Stuesser, N [Hahn-Meitner Institut, Glienicker Strasse 100, 14109, Berlin (Germany); Hense, K; Gratz, E [Institute for Experimental Physics, Technical University Vienna, Wiedner Hauptstrasse 8-10, A-1040 (Austria); Rotter, M [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, 1090 Wien (Austria)], E-mail: paulbon@glvt-cnrs.fr
2008-03-12
The magnetic phase diagram of Ho-Ag has been established using magnetoresistance, magnetostriction and neutron diffraction experiments versus applied field and temperature. Three different magnetic phases were observed: an incommensurate antiferromagnetic phase (IC) below T{sub N} = 33 K, a commensurate antiferromagnetic phase (C) above 5 T and below T{sub 1} (5-8 K) and a ferromagnetic component above 3 T. The IC phase undergoes spin reorientations around 5 T (IC') and 13 T (IC'')
Binary Colloidal Alloy Test-5: Phase Separation
Lynch, Matthew; Weitz, David A.; Lu, Peter J.
2008-01-01
The Binary Colloidal Alloy Test - 5: Phase Separation (BCAT-5-PhaseSep) experiment will photograph initially randomized colloidal samples onboard the ISS to determine their resulting structure over time. This allows the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-PhaseSep studies collapse (phase separation rates that impact product shelf-life); in microgravity the physics of collapse is not masked by being reduced to a simple top and bottom phase as it is on Earth.
The geometric phase in quantum physics
Energy Technology Data Exchange (ETDEWEB)
Bohm, A.
1993-03-01
After an explanatory introduction, a quantum system in a classical time-dependent environment is discussed; an example is a magnetic moment in a classical magnetic field. At first, the general abelian case is discussed in the adiabatic approximation. Then the geometric phase for nonadiabatic change of the environment (Anandan--Aharonov phase) is introduced, and after that general cyclic (nonadiabatic) evolution is discussed. The mathematics of fiber bundles is introduced, and some of its results are used to describe the relation between the adiabatic Berry phase and the geometric phase for general cyclic evolution of a pure state. The discussion is restricted to the abelian, U(1) phase.
QGP phase transition and multiplicity fluctuations
Institute of Scientific and Technical Information of China (English)
杨纯斌; 王晓荣; 蔡勖
1997-01-01
The scaled factorial moments in QGP phase transitions are studied analytically by the extended Ginzburg-Landau model.The dependence of InFq on phase space interval is different for the first- and second-order QGP phase transitions.When lnFq are fitted to polynomials of X=δ1/3,the relative sign between the fitted coefficients of X and bq,l calculated theoretically can be used to judge the order of phase transitions.Two sets of experimental data are reanalysed and the phase transitions are the first order for one set of data but the second order for another.
On the notion of phase in mechanics
Energy Technology Data Exchange (ETDEWEB)
Gosson, Maurice A de [Department of Mathematics, Blekinge Institute of Technology, SE-371 79 Karlskrona (Sweden)
2004-07-23
The notion of phase plays an essential role in both semiclassical and quantum mechanics. But what is exactly a phase, and how does it change with time? It turns out that the most universal definition of a phase can be given in terms of Lagrangian manifolds by exploiting the properties of the Poincare-Cartan form. Such a phase is defined, not in configuration space, but rather in phase-space and is thus insensitive to the appearance of caustics. Surprisingly enough, this approach allows us to recover the Heisenberg-Weyl formalism without invoking commutation relations for observables.
Adiabatic geometric phases in hydrogenlike atoms
Sjöqvist, Erik; Yi, X. X.; Åberg, Johan
2005-11-01
We examine the effect of spin-orbit coupling on geometric phases in hydrogenlike atoms exposed to a slowly varying magnetic field. The marginal geometric phases associated with the orbital angular momentum and the intrinsic spin fulfill a sum rule that explicitly relates them to the corresponding geometric phase of the whole system. The marginal geometric phases in the Zeeman and Paschen-Back limits are analyzed. We point out the existence of nodal points in the marginal phases that may be detected by topological means.
Adiabatic geometric phases in hydrogenlike atoms
Sjöqvist, E; Sj\\"{o}qvist, Erik
2005-01-01
We examine the effect of spin-orbit coupling on geometric phases in hydrogenlike atoms exposed to a slowly varying magnetic field. The marginal geometric phases associated with the orbital angular momentum and the intrinsic spin fulfill a sum rule that explicitly relates them to the corresponding geometric phase of the whole system. The marginal geometric phases in the Zeeman and Paschen-Back limit are analyzed. We point out the existence of nodal points in the marginal phases that may be detected by topological means.
Pharm GKB: Acute-Phase Reaction [PharmGKB
Lifescience Database Archive (English)
Full Text Available Overview Alternate Names: Synonym Acute Phase Reaction; Acute Phase State; Acute-Phase Response; Acute...-Phase State; Reaction, Acute Phase; Reaction, Acute-Phase; Response, Acute Phase; Response, Acute...-Phase; State, Acute-Phase PharmGKB Accession Id: PA443262 External Vocabularies MeSH: Acute-Phase ...Reaction (D000210) UMLS: Acute-Phase Reaction [Disease/Finding] (C0001349) NDFRT: Acute...-Phase Reaction [Disease/Finding] (N0000000303) Common Searches Search Medline Plus Search CTD Pharm GKB: Acute-Phase Reaction ...
Polymers in phase change materials
Energy Technology Data Exchange (ETDEWEB)
Ferreira, M.C.; Brites, M.J.; Alexandre, J.H. [National Lab. for Energy and Geology, Lisbon (Portugal)
2010-07-01
Phase Change Materials (PCMs) which are the core of latent heat thermal energy storage systems are currently an area of investigation of increasing interest. Several substances differing in physical and chemical characteristics as well as in thermal behavior have been studied as PCMS{sup 1-3}. In order to meet the requisites of particular systems, auxiliary materials are often used with specific functions. This bibliographic survey shows that polymeric materials have been proposed either as the PCM itself in solid-liquid or solid-solid transitions or to perform auxiliary functions of shape stabilisation and microencapsulation for solid-liquid PCMs. The PCMs have an operating temperature ranging from around 0 C (for the system water/polyacrilamid) to around 127 C (for crosslinked HDPE). (orig.)
Heisel, Mark
2014-09-01
The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta decay (0 νββ) of 76Ge. It is a process that violates lepton number conservation and is predicted to occur in extensions of the standard model of particle physics. GERDA is located underground in the Gran Sasso National Laboratory (LNGS), Italy. An array of bare high-purity germanium detectors enriched in 76Ge is operated in a cryostat with 64 m3 of liquid argon supplemented by a 3 m thick shield of water. The experiment aims at exploring the 0 νββ decay up to a half life of 2 .1026 yr in two phases: Phase I of the experiment has been concluded last year. No signal is observed and the so far best limit is derived for the half life of the 0 νββ decay of 76Ge, T1/20ν power. Low mass detector holders, cold front-end electronics, contacting and cabling schemes are redesigned for ultra low mass and radiopurity. In addition, a retractable liquid argon veto will be installed to efficiently suppress background events that induce scintillation in the liquid argon. A hybrid solution of photomultiplier tubes and silicon photomultipliers coupled to scintillating fibres was chosen. This talk gives an account of the results and these challenging modifications to meet our design goals. The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta decay (0 νββ) of 76Ge. It is a process that violates lepton number conservation and is predicted to occur in extensions of the standard model of particle physics. GERDA is located underground in the Gran Sasso National Laboratory (LNGS), Italy. An array of bare high-purity germanium detectors enriched in 76Ge is operated in a cryostat with 64 m3 of liquid argon supplemented by a 3 m thick shield of water. The experiment aims at exploring the 0 νββ decay up to a half life of 2 .1026 yr in two phases: Phase I of the experiment has been concluded last year. No signal is observed and the so far best
Phase-Occultation Nulling Coronagraphy
Lyon, Richard G; Clampin, Mark; Petrone, Peter
2015-01-01
The search for life via characterization of earth-like planets in the habitable zone is one of the key scientific objectives in Astronomy. We describe a new phase-occulting (PO) interferometric nulling coronagraphy (NC) approach. The PO-NC approach employs beamwalk and freeform optical surfaces internal to the interferometer cavity to introduce a radially dependent plate scale difference between each interferometer arm (optical path) that nulls the central star at high contrast while transmitting the off-axis field. The design is readily implemented on segmented-mirror telescope architectures, utilizing a single nulling interferometer to achieve high throughput, a small inner working angle (IWA), sixth-order or higher starlight suppression, and full off-axis discovery space, a combination of features that other coronagraph designs generally must trade. Unlike previous NC approaches, the PO-NC approach does not require pupil shearing; this increases throughput and renders it less sensitive to on-axis common-mo...
Phase Synchronization in Railway Timetables
Fretter, Christoph; Weihe, Karsten; Müller-Hannemann, Matthias; Hütt, Marc-Thorsten
2010-01-01
Timetable construction belongs to the most important optimization problems in public transport. Finding optimal or near-optimal timetables under the subsidiary conditions of minimizing travel times and other criteria is a targeted contribution to the functioning of public transport. In addition to efficiency (given, e.g., by minimal average travel times), a significant feature of a timetable is its robustness against delay propagation. Here we study the balance of efficiency and robustness in long-distance railway timetables (in particular the current long-distance railway timetable in Germany) from the perspective of synchronization, exploiting the fact that a major part of the trains run nearly periodically. We find that synchronization is highest at intermediate-sized stations. We argue that this synchronization perspective opens a new avenue towards an understanding of railway timetables by representing them as spatio-temporal phase patterns. Robustness and efficiency can then be viewed as properties of t...
Sliding Over a Phase Transition
Tosatti, Erio; Benassi, Andrea; Vanossi, Andrea; Santoro, Giuseppe E.
2011-03-01
The frictional response experienced by a stick-slip slider when a phase transition occurs in the underlying solid substrate is a potentially exciting, poorly explored problem. We show, based on 2-dimensional simulations modeling the sliding of a nanotip, that indeed friction may be heavily affected by a continuous structural transition. First, friction turns nonmonotonic as temperature crosses the transition, peaking at the critical temperature Tc where fluctuations are strongest. Second, below Tc friction depends upon order parameter directions, and is much larger for those where the frictional slip can cause a local flip. This may open a route towards control of atomic scale friction by switching the order parameter direction by an external field or strain, with possible application to e.g., displacive ferroelectrics such as BaTi O3 , as well as ferro- and antiferro-distortive materials. Supported by project ESF FANAS/AFRI sponsored by the Italian Research Council (CNR).
Phase transitions at finite density
Friman, Bengt
2012-01-01
I discuss the analytic structure of thermodynamic quantities for complex values of thermodynamic variables within Landau theory. In particular, the singularities connected with phase transitions of second order, first order and cross over types are examined. A conformal mapping is introduced, which may be used to explore the thermodynamics of strongly interacting matter at finite values of the baryon chemical potential $\\mu$ starting from lattice QCD results at $\\mu^{2}\\leq 0$. This method allows us to improve the convergence of a Taylor expansion about $\\mu=0$ and to enhance the sensitivity to physical singularities in the complex $\\mu$ plane. The technique is illustrated by an application to a second-order transition in a chiral effective model.
Physics of collisionless phase mixing
Tsiklauri, D
2008-01-01
A previous study [Tsiklauri et al., 2005, Astron. Astrophys., 435, 1105] of phase mixing of ion cyclotron (IC), Alfvenic, waves in the collisionless regime has established the generation of parallel electric field and hence acceleration of electrons in the regions of transverse density inhomogeneity. However, outstanding issues were left open. Here we bridge the gap in understanding by establishing the following: (i) Using the generalised Ohm's law we find that the parallel electric field is supported mostly by the electron pressure tensor, with a smaller contribution from the electron inertia term. (ii) The generated parallel electric field and the fraction of accelerated electrons are independent of the IC wave frequency remaining at a level of six orders of magnitude larger than the Dreicer value and approximately 20% respectively. The generated parallel electric field and the fraction of accelerated electrons increase with the increase of IC wave amplitude. The generated parallel electric field seems to b...
Montoya, Juan; Sanchez-Rubio, Antonio; Hatch, Robert; Payson, Harold
2014-11-01
We demonstrate a ladar with 0.5 m class range resolution obtained by integrating a continuous-wave optical phased-array transmitter with a Geiger-mode avalanche photodiode receiver array. In contrast with conventional ladar systems, an array of continuous-wave sources is used to effectively pulse illuminate a target by electro-optically steering far-field fringes. From the reference frame of a point in the far field, a steered fringe appears as a pulse. Range information is thus obtained by measuring the arrival time of a pulse return from a target to a receiver pixel. This ladar system offers a number of benefits, including broad spectral coverage, high efficiency, small size, power scalability, and versatility.
Two-phase viscoelastic jetting
Energy Technology Data Exchange (ETDEWEB)
Yu, J-D; Sakai, S.; Sethian, J.A.
2008-12-10
A coupled finite difference algorithm on rectangular grids is developed for viscoelastic ink ejection simulations. The ink is modeled by the Oldroyd-B viscoelastic fluid model. The coupled algorithm seamlessly incorporates several things: (1) a coupled level set-projection method for incompressible immiscible two-phase fluid flows; (2) a higher-order Godunov type algorithm for the convection terms in the momentum and level set equations; (3) a simple first-order upwind algorithm for the convection term in the viscoelastic stress equations; (4) central difference approximations for viscosity, surface tension, and upper-convected derivative terms; and (5) an equivalent circuit model to calculate the inflow pressure (or flow rate) from dynamic voltage.
Simplicity in simplicial phase space
Dittrich, Bianca
2010-01-01
A key point in the spin foam approach to quantum gravity is the implementation of simplicity constraints in the partition functions of the models. Here, we discuss the imposition of these constraints in a phase space setting corresponding to simplicial geometries. On the one hand, this could serve as a starting point for a derivation of spin foam models by canonical quantisation. On the other, it elucidates the interpretation of the boundary Hilbert space that arises in spin foam models. More precisely, we discuss different versions of the simplicity constraints, namely gauge-variant and gauge-invariant versions. In the gauge-variant version, the primary and secondary simplicity constraints take a similar form to the reality conditions known already in the context of (complex) Ashtekar variables. Subsequently, we describe the effect of these primary and secondary simplicity constraints on gauge-invariant variables. This allows us to illustrate their equivalence to the so-called diagonal, cross and edge simpli...
Photovoltaic Manufacturing Technology Phase 1
Energy Technology Data Exchange (ETDEWEB)
Stern, M.J. (Utility Power Group, Chatsworth, CA (United States))
1991-11-01
This report documents Utility Power Group's (UPG) contract under Phase 1 of the Photovoltaic Manufacturing Technology (PVMaT) project. Specifically, the report contains the results of a manufacturing technology cost analysis based on an existing PV module production facility. It also projects the cost analysis of a future production facility based on a larger module area, a larger production rate, and the elimination of several technical obstacles. With a coordinated 18-month engineering effort, the technical obstacles could be overcome. Therefore, if solutions to the financial obstacles concerning production expansion were found, UPG would be able to manufacture PV modules at a cost of under $1.25 per watt by 1994.
Omnidirectional antenna having constant phase
Energy Technology Data Exchange (ETDEWEB)
Sena, Matthew
2017-04-04
Various technologies presented herein relate to constructing and/or operating an antenna having an omnidirectional electrical field of constant phase. The antenna comprises an upper plate made up of multiple conductive rings, a lower ground-plane plate, a plurality of grounding posts, a conical feed, and a radio frequency (RF) feed connector. The upper plate has a multi-ring configuration comprising a large outer ring and several smaller rings of equal size located within the outer ring. The large outer ring and the four smaller rings have the same cross-section. The grounding posts ground the upper plate to the lower plate while maintaining a required spacing/parallelism therebetween.
Liquid phase chromatography on microchips.
Kutter, Jörg P
2012-01-20
Over the past twenty years, the field of microfluidics has emerged providing one of the main enabling technologies to realize miniaturized chemical analysis systems, often referred to as micro-Total Analysis Systems (uTAS), or, more generally, Lab-on-a-Chip Systems (LOC) [1,2]. While microfluidics was driven forward a lot from the engineering side, especially with respect to ink jet and dispensing technology, the initial push and interest from the analytical chemistry community was through the desire to develop miniaturized sensors, detectors, and, very early on, separation systems. The initial almost explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important to keep in mind when developing or working with separations in a miniaturized format, and what challenges and pitfalls remain.
Liquid phase chromatography on microchips
DEFF Research Database (Denmark)
Kutter, Jörg Peter
2012-01-01
Over the past twenty years, the field of microfluidics has emerged providing one of the main enabling technologies to realize miniaturized chemical analysis systems, often referred to as micro-Total Analysis Systems (uTAS), or, more generally, Lab-on-a-Chip Systems (LOC) [1,2]. While microfluidics...... was driven forward a lot from the engineering side, especially with respect to ink jet and dispensing technology, the initial push and interest from the analytical chemistry community was through the desire to develop miniaturized sensors, detectors, and, very early on, separation systems. The initial almost...... explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...
Phase Transformation Dynamics in Porous Battery Electrodes
Ferguson, Todd R
2014-01-01
Porous electrodes composed of multiphase active materials are widely used in Li-ion batteries, but their dynamics are poorly understood. Two-phase models are largely empirical, and no models exist for three or more phases. Using a modified porous electrode theory based on non-equilibrium thermodynamics, we show that experimental phase behavior can be accurately predicted from free energy models, without artificially placing phase boundaries or fitting the open circuit voltage. First, we simulate lithium intercalation in porous iron phosphate, a popular two-phase cathode, and show that the zero-current voltage gap, sloping voltage plateau and under-estimated exchange currents all result from size-dependent nucleation and mosaic instability. Next, we simulate porous graphite, the standard anode with three stable phases, and reproduce experimentally observed fronts of color-changing phase transformations. These results provide a framework for physics-based design and control for electrochemical systems with comp...
Electric field controlled emulsion phase contactor
Scott, Timothy C.
1995-01-01
A system for contacting liquid phases comprising a column for transporting a liquid phase contacting system, the column having upper and lower regions. The upper region has a nozzle for introducing a dispersed phase and means for applying thereto a vertically oriented high intensity pulsed electric field. This electric field allows improved flow rates while shattering the dispersed phase into many micro-droplets upon exiting the nozzle to form a dispersion within a continuous phase. The lower region employs means for applying to the dispersed phase a horizontally oriented high intensity pulsed electric field so that the dispersed phase undergoes continuous coalescence and redispersion while being urged from side to side as it progresses through the system, increasing greatly the mass transfer opportunity.
Holographic Phase Transition Probed by Nonlocal Observables
Directory of Open Access Journals (Sweden)
Xiao-Xiong Zeng
2016-01-01
Full Text Available From the viewpoint of holography, the phase structure of a 5-dimensional Reissner-Nordström-AdS black hole is probed by the two-point correlation function, Wilson loop, and entanglement entropy. As the case of thermal entropy, we find for all the probes that the black hole undergoes a Hawking-Page phase transition, a first-order phase transition, and a second-order phase transition successively before it reaches a stable phase. In addition, for these probes, we find that the equal area law for the first-order phase transition is valid always and the critical exponent of the heat capacity for the second-order phase transition coincides with that of the mean field theory regardless of the size of the boundary region.
Gas-Liquid Flows and Phase Separation
McQuillen, John
2004-01-01
Common issues for space system designers include:Ability to Verify Performance in Normal Gravity prior to Deployment; System Stability; Phase Accumulation & Shedding; Phase Separation; Flow Distribution through Tees & Manifolds Boiling Crisis; Heat Transfer Coefficient; and Pressure Drop.The report concludes:Guidance similar to "A design that operates in a single phase is less complex than a design that has two-phase flow" is not always true considering the amount of effort spent on pressurizing, subcooling and phase separators to ensure single phase operation. While there is still much to learn about two-phase flow in reduced gravity, we have a good start. Focus now needs to be directed more towards system level problems .
The eigenvalue problem in phase space.
Cohen, Leon
2017-07-27
We formulate the standard quantum mechanical eigenvalue problem in quantum phase space. The equation obtained involves the c-function that corresponds to the quantum operator. We use the Wigner distribution for the phase space function. We argue that the phase space eigenvalue equation obtained has, in addition to the proper solutions, improper solutions. That is, solutions for which no wave function exists which could generate the distribution. We discuss the conditions for ascertaining whether a position momentum function is a proper phase space distribution. We call these conditions psi-representability conditions, and show that if these conditions are imposed, one extracts the correct phase space eigenfunctions. We also derive the phase space eigenvalue equation for arbitrary phase space distributions functions. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Power inverter implementing phase skipping control
Somani, Utsav; Amirahmadi, Ahmadreza; Jourdan, Charles; Batarseh, Issa
2016-10-18
A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.
Accelerated Adaptive MGS Phase Retrieval
Lam, Raymond K.; Ohara, Catherine M.; Green, Joseph J.; Bikkannavar, Siddarayappa A.; Basinger, Scott A.; Redding, David C.; Shi, Fang
2011-01-01
The Modified Gerchberg-Saxton (MGS) algorithm is an image-based wavefront-sensing method that can turn any science instrument focal plane into a wavefront sensor. MGS characterizes optical systems by estimating the wavefront errors in the exit pupil using only intensity images of a star or other point source of light. This innovative implementation of MGS significantly accelerates the MGS phase retrieval algorithm by using stream-processing hardware on conventional graphics cards. Stream processing is a relatively new, yet powerful, paradigm to allow parallel processing of certain applications that apply single instructions to multiple data (SIMD). These stream processors are designed specifically to support large-scale parallel computing on a single graphics chip. Computationally intensive algorithms, such as the Fast Fourier Transform (FFT), are particularly well suited for this computing environment. This high-speed version of MGS exploits commercially available hardware to accomplish the same objective in a fraction of the original time. The exploit involves performing matrix calculations in nVidia graphic cards. The graphical processor unit (GPU) is hardware that is specialized for computationally intensive, highly parallel computation. From the software perspective, a parallel programming model is used, called CUDA, to transparently scale multicore parallelism in hardware. This technology gives computationally intensive applications access to the processing power of the nVidia GPUs through a C/C++ programming interface. The AAMGS (Accelerated Adaptive MGS) software takes advantage of these advanced technologies, to accelerate the optical phase error characterization. With a single PC that contains four nVidia GTX-280 graphic cards, the new implementation can process four images simultaneously to produce a JWST (James Webb Space Telescope) wavefront measurement 60 times faster than the previous code.
Machine Phase Fullerene Nanotechnology: 1996
Globus, Al; Chancellor, Marisa K. (Technical Monitor)
1997-01-01
NASA has used exotic materials for spacecraft and experimental aircraft to good effect for many decades. In spite of many advances, transportation to space still costs about $10,000 per pound. Drexler has proposed a hypothetical nanotechnology based on diamond and investigated the properties of such molecular systems. These studies and others suggest enormous potential for aerospace systems. Unfortunately, methods to realize diamonoid nanotechnology are at best highly speculative. Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically relatively accessible and of great aerospace interest. Machine phase materials are (hypothetical) materials consisting entirely or in large part of microscopic machines. In a sense, most living matter fits this definition. To begin investigation of fullerene nanotechnology, we used molecular dynamics to study the properties of carbon nanotube based gears and gear/shaft configurations. Experiments on C60 and quantum calculations suggest that benzyne may react with carbon nanotubes to form gear teeth. Han has computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Results suggest that rotation can be converted to rotating or linear motion, and linear motion may be converted into rotation. Preliminary results suggest that these mechanical systems can be cooled by a helium atmosphere. Furthermore, Deepak has successfully simulated using helical electric fields generated by a laser to power fullerene gears once a positive and negative charge have been added to form a dipole. Even with mechanical motion, cooling, and power; creating a viable nanotechnology requires support structures, computer control, a system architecture, a variety of components, and some approach to manufacture. Additional
Ikram, Nabia S; Yee, Judy; Weinstein, Stefanie; Yeh, Benjamin M; Corvera, Carlos U; Monto, Alexander; Hope, Thomas A
2017-03-01
To establish if triple-phase arterial imaging improves the detection of arterial phase hyperintense lesions based on arterial phase capture, motion artifact degradation, and lesion enhancement when compared to single-phase imaging. Patients at risk for hepatocellular carcinoma were imaged at 3.0T. Seventy-three consecutive patients with a standard single-phase MRI and eighty-five consecutive patients were imaged using extracellular contrast with triple arterial phase MRI using three sequential accelerated acquisitions of 8 s. Arterial phase capture and image quality were qualitatively categorized. Forty single-phase and forty-four triple-phase studies contained arterially enhancing lesions > 1 cm with washout appearance. The contrast-to-noise ratio (CNR) of the lesions was calculated. We compared the differences in means with Student t-tests and those in arterial phase capture with a Chi squared test with Yates correction. The triple-phase acquisitions captured the early or late arterial phases more frequently than did the single-phase acquisition (99% vs 86%; P value = 0.006). Triple-phase also provided greater number of patients with early or late arterial phase imaging without motion artifact (92% vs 79%, P-value = 0.05). The lesion analysis revealed increased maximum CNR in the triple-phase imaging (704.4) vs. single-phase imaging (517.2), P-value phase acquisition provides more robust arterial phase imaging for hepatic lesions, with increased lesion CNR, compared to standard single-phase arterial phase imaging.
RESEARCH ON METHOD TO CALCULATE VELOCITIES OF SOLID PHASE AND LIQUID PHASE IN DEBRIS FLOW
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two-phase liquid composed of solid phase with the same diameter particles and liquid phase with the same mechanical features. Assume debris flow was one-dimension two-phase liquid moving to one direction,then general equations of velocities of solid phase and liquid phase were founded in twophase theory. Methods to calculate average pressures, volume forces and surface forces of debris flow control volume were established. Specially, surface forces were ascertained using Bingham's rheology equation of liquid phase and Bagnold's testing results about interaction between particles of solid phase. Proportional coefficient of velocities between liquid phase and solid phase was put forward, meanwhile, divergent coefficient between theoretical velocity and real velocity of solid phase was provided too. To state succinctly before, method to calculate velocities of solid phase and liquid phase was obtained through solution to general equations. The method is suitable for both viscous debris flow and thin debris flow. Additionally, velocities every phase can be identified through analyzing deposits in-situ after occurring of debris flow. It is obvious from engineering case the result in the method is consistent to that in real-time field observation.
A NEW ALGORITHM FOR ELIMINATING PHASE-SHIFT ERROR IN PHASE SHIFTING INTERFEROMETRY
Institute of Scientific and Technical Information of China (English)
无
1999-01-01
The effect of phase-shift error in phase shifting interferometry is investigated. A new algorithm with two sets of 4 samples for eliminating phase-shift error is presented. The computer simulation and experiment result show that the phase-shift offset should be π when the algorithm is used, and this algorithm has gotten better result than the original 4-sample algorithm.
Three-Phase and Six-Phase AC at the Lab Bench
Caplan, George M.
2009-01-01
Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way…
Ahmad Panahi, Homayon; Ejlali, Maryam; Chabouk, Monireh
2016-07-01
This paper reports the applicability of two-phase and three-phase hollow fiber based liquid-phase microextraction (HF-LPME) for the extraction of hydrochlorothiazide (HYD) and triamterene (TRM) from human urine. The HYD in two-phase HF-LPME is extracted from 24 mL of the aqueous sample into an organic phase with microliter volume located inside the pores and lumen of a polypropylene hollow fiber as acceptor phase, but the TRM in three-phase HF-LPME is extracted from aqueous donor phase to organic phase and then back-extracted to the aqueous acceptor phase, which can be directly injected into HPLC for analysis. Under optimized conditions preconcentration factors of HYD and TRM were obtained as 128 and 239, respectively. The calibration curves were linear (R(2) ≥ 0.995) in the concentration range of 1.0-100 µg/L for HYD and 2.0-100 µg/L for TRM. The limits of detection for HYD and TRM were 0.5 µg/L. The intra-day and inter-day RSD based on four replicates were obtained as ≤5.8 and ≤9.3%, respectively. The methods were successfully applied for determining the concentration of the drugs in urine samples. Copyright © 2015 John Wiley & Sons, Ltd.
Microbial growth with vapor-phase substrate
Energy Technology Data Exchange (ETDEWEB)
Hanzel, Joanna; Thullner, Martin; Harms, Hauke [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany); Wick, Lukas Y., E-mail: lukas.wick@ufz.de [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany)
2011-04-15
Limited information exists on influences of the diffusive transport of volatile organic contaminants (VOC) on bacterial activity in the unsaturated zone of the terrestrial subsurface. Diffusion of VOC in the vapor-phase is much more efficient than in water and results in effective VOC transport and high bioavailability despite restricted mobility of bacteria in the vadose zone. Since many bacteria tend to accumulate at solid-water, solid-air and air-water interfaces, such phase boundaries are of a special interest for VOC-biodegradation. In an attempt to evaluate microbial activity toward air-borne substrates, this study investigated the spatio-temporal interplay between growth of Pseudomonas putida (NAH7) on vapor-phase naphthalene (NAPH) and its repercussion on vapor-phase NAPH concentrations. Our data demonstrate that growth rates of strain PpG7 were inversely correlated to the distance from the source of vapor-phase NAPH. Despite the high gas phase diffusivity of NAPH, microbial growth was absent at distances above 5 cm from the source when sufficient biomass was located in between. This indicates a high efficiency of suspended bacteria to acquire vapor-phase compounds and influence headspace concentration gradients at the centimeter-scale. It further suggests a crucial role of microorganisms as biofilters for gas-phase VOC emanating from contaminated groundwater or soil. - Research highlights: > Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene. > Bacteria influence NAPH vapor-phase concentration gradients at centimeter-scale. > Microbial growth on vapor-phase naphthalene is inversely correlated to its source. > Bacteria are good biofilters for gas-phase NAPH emanating from contaminated sites. - Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene and effectively influence vapor-phase naphthalene concentration gradients at the centimeter scale.
Near-field x-ray phase contrast imaging and phase retrieval algorithm
Institute of Scientific and Technical Information of China (English)
Zhu Hua-Feng; Xie Hong-Lan; Gao Hong-Yi; Chen Jian-Wen; Li Ru-Xin; Xu Zhi-Zhan
2005-01-01
Theoretical analyses of x-ray diffraction phase contrast imaging and near field phase retrieval method are presented.A new variant of the near field intensity distribution is derived with the optimal phase imaging distance and spatial frequency of object taken into account. Numerical examples of phase retrieval using simulated data are also given. On the above basis, the influence of detecting distance and polychroism of radiation on the phase contrast image and the retrieved phase distribution are discussed. The present results should be useful in the practical application of in-line phase contrast imaging.
A Novel Phase-Locking-Free Phase Sensitive Amplifier based Regenerator
DEFF Research Database (Denmark)
Kjøller, Niels-Kristian; Røge, Kasper Meldgaard; Guan, Pengyu
2016-01-01
We propose a scheme for phase regeneration of optical binary phase-shift keying (BPSK) data signals based on phase sensitive amplification without active phase-locking. A delay interferometer (DI) is used to convert a BPSK signal impaired by noise to an amplitude modulated signal followed by cross-phase......-locked pumps. As a result, active phase-stabilization is avoided. A proof-of-principle experiment is carried out with a dual-pump degenerate phase sensitive amplifier (PSA), demonstrating regeneration for a 10 Gb/s non-return-to-zero differential BPSK (NRZ-DPSK) data signal degraded by a sinusoidal phase-noise...... tone. Receiver sensitivity improvements of 3.5 dB are achieved at a bit-error-rate (BER) of 10-9. Additionally, numerical simulations are performed comparing the idealized regenerator performance in the presence of sinusoidal phase modulation as well as Gaussian phase-noise....
Phase Noise Influence in Optical OFDM Systems employing RF Pilot Tone for Phase Noise Cancellation
Jacobsen, Gunnar; Kazovsky, Leonid G.; Xu, TianHua; Popov, Sergei; Li, Jie; Zhang, Yimo; Friberg, Ari T.
2016-01-01
For coherent and direct-detection Orthogonal Frequency Division Multiplexed (OFDM) systems employing radio frequency (RF) pilot tone phase noise cancellation the influence of laser phase noise is evaluated. Novel analytical results for the common phase error and for the (modulation dependent) inter carrier interference are evaluated based upon Gaussian statistics for the laser phase noise. In the evaluation it is accounted for that the laser phase noise is filtered in the correlation signal d...
Phase Spectral Analysis of EEG Signals
Institute of Scientific and Technical Information of China (English)
YOURong-yi; CHENZhong
2004-01-01
A new method of phase spectral analysis of EEG is proposed for the comparative analysis of phase spectra between normal EEG and epileptic EEG signals based on the wavelet decomposition technique. By using multiscale wavelet decomposition, the original EEGs are mapped to an orthogonal wavelet space, such that the variations of phase can be observed at multiscale. It is found that the phase (and phase difference) spectra of normal EEGs are distinct from that of epileptic EEGs. That is the variations of phase (and phase difference) of normal EEGs have a distinct periodic pattern with the electrical activity proceeds in the brain, but do not the epileptic EEGs. For epileptic EEGs, only at those transient points, the phase variations are obvious. In order to verify these results with the observational data, the phase variations of EEGs in principal component space are observed and found that, the features of phase spectra is in correspondence with that the wavelet space. These results make it possible to view the behavior of EEG rhythms as a dynamic spectrum.
Phase extraction in disordered isospectral shapes.
Ţolea, Mugurel; Ostahie, Bogdan; Niţă, Marian; Ţolea, Felicia; Aldea, Alexandru
2012-03-01
The phase of the electronic wave function is not directly measurable but, quite remarkably, it becomes accessible in pairs of isospectral shapes, as recently proposed in the experiment by Moon et al. [Science 319, 782 (2008)]. The method is based on a special property, called transplantation, which relates the eigenfunctions of the isospectral pairs, and allows us to extract the phase distributions, if the amplitude distributions are known. We numerically simulate such a phase extraction procedure in the presence of disorder, which is introduced both as Anderson disorder and as roughness at edges. With disorder, the transplantation can no longer lead to a perfect fit of the wave functions, however we show that a phase can still be extracted-defined as the phase that minimizes the misfit. Interestingly, this extracted phase coincides with (or differs negligibly from) the phase of the disorder-free system, up to a certain disorder amplitude, and a misfit of the wave functions as high as ~5%, proving a robustness of the phase extraction method against disorder. However, if the disorder is increased further, the extracted phase shows a puzzle structure, no longer correlated with the phase of the disorder-free system. A discrete model is used, which is the natural approach for disorder analysis. We provide a proof that discretization preserves isospectrality and the transplantation can be adapted to the discrete systems.
Array Phase Shifters: Theory and Technology
Romanofsky, Robert R.
2007-01-01
While there are a myriad of applications for microwave phase shifters in instrumentation and metrology, power combining, amplifier linearization, and so on, the most prevalent use is in scanning phased-array antennas. And while this market continues to be dominated by military radar and tracking platforms, many commercial applications have emerged in the past decade or so. These new and potential applications span low-Earth-orbit (LEO) communications satellite constellations and collision warning radar, an aspect of the Intelligent Vehicle Highway System or Automated Highway System. In any case, the phase shifters represent a considerable portion of the overall antenna cost, with some estimates approaching 40 percent for receive arrays. Ferrite phase shifters continue to be the workhorse in military-phased arrays, and while there have been advances in thin film ferrite devices, the review of this device technology in the previous edition of this book is still highly relevant. This chapter will focus on three types of phase shifters that have matured in the past decade: GaAs MESFET monolithic microwave integrated circuit (MMIC), micro-electromechanical systems (MEMS), and thin film ferroelectric-based devices. A brief review of some novel devices including thin film ferrite phase shifters and superconducting switches for phase shifter applications will be provided. Finally, the effects of modulo 2 phase shift limitations, phase errors, and transient response on bit error rate degradation will be considered.
Stereo 3D spatial phase diagrams
Energy Technology Data Exchange (ETDEWEB)
Kang, Jinwu, E-mail: kangjw@tsinghua.edu.cn; Liu, Baicheng, E-mail: liubc@tsinghua.edu.cn
2016-07-15
Phase diagrams serve as the fundamental guidance in materials science and engineering. Binary P-T-X (pressure–temperature–composition) and multi-component phase diagrams are of complex spatial geometry, which brings difficulty for understanding. The authors constructed 3D stereo binary P-T-X, typical ternary and some quaternary phase diagrams. A phase diagram construction algorithm based on the calculated phase reaction data in PandaT was developed. And the 3D stereo phase diagram of Al-Cu-Mg ternary system is presented. These phase diagrams can be illustrated by wireframe, surface, solid or their mixture, isotherms and isopleths can be generated. All of these can be displayed by the three typical display ways: electronic shutter, polarization and anaglyph (for example red-cyan glasses). Especially, they can be printed out with 3D stereo effect on paper, and watched by the aid of anaglyph glasses, which makes 3D stereo book of phase diagrams come to reality. Compared with the traditional illustration way, the front of phase diagrams protrude from the screen and the back stretches far behind of the screen under 3D stereo display, the spatial structure can be clearly and immediately perceived. These 3D stereo phase diagrams are useful in teaching and research. - Highlights: • Stereo 3D phase diagram database was constructed, including binary P-T-X, ternary, some quaternary and real ternary systems. • The phase diagrams can be watched by active shutter or polarized or anaglyph glasses. • The print phase diagrams retains 3D stereo effect which can be achieved by the aid of anaglyph glasses.
Stiffness of lipid monolayers with phase coexistence.
Caruso, Benjamín; Mangiarotti, Agustín; Wilke, Natalia
2013-08-27
The surface dilational modulus--or compressibility modulus--has been previously studied for monolayers composed of pure materials, where a jump in this modulus was related with the onset of percolation as a result of the establishment of a connected structure at the molecular level. In this work, we focused on monolayers composed of two components of low lateral miscibility. Our aim was to investigate the compressibility of mixed monolayers at pressures and compositions in the two-phase region of the phase diagram, in order to analyze the effect of the mechanical properties of each phase on the stiffness of the composite. In nine different systems with distinct molecular dipoles and charges, the stiffness of each phase and the texture at the plane of the monolayer were studied. In this way, we were able to analyze the general compressibility of two-phase lipid monolayers, regardless of the properties of their constituent parts. The results are discussed in the light of the following two hypotheses: first, the stiffness of the composite could be dominated by the stiffness of each phase as a weighted sum according to the percentage of each phase area, regardless of the distribution of the phases in the plane of the monolayer. Alternatively, the stiffness of the composite could be dominated by the mechanical properties of the continuous phase. Our results were better explained by this latter proposal, as in all the analyzed mixtures it was found that the mechanical properties of the percolating phase were the determining factors. The value of the compression modulus was closer to the value of the connected phase than to that of the dispersed phase, indicating that the bidimensional composites displayed mechanical properties that were related to the properties of each phases in a rather complex manner.
Pure Phase Solubility Limits: LANL
Energy Technology Data Exchange (ETDEWEB)
C. Stockman
2001-01-26
The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility
Döring, Barbara; Petzinger, Ernst
2014-08-01
The historical phasing concept of drug metabolism and elimination was introduced to comprise the two phases of metabolism: phase I metabolism for oxidations, reductions and hydrolyses, and phase II metabolism for synthesis. With this concept, biological membrane barriers obstructing the accessibility of metabolism sites in the cells for drugs were not considered. The concept of two phases was extended to a concept of four phases when drug transporters were detected that guided drugs and drug metabolites in and out of the cells. In particular, water soluble or charged drugs are virtually not able to overcome the phospholipid membrane barrier. Drug transporters belong to two main clusters of transporter families: the solute carrier (SLC) families and the ATP binding cassette (ABC) carriers. The ABC transporters comprise seven families with about 20 carriers involved in drug transport. All of them operate as pumps at the expense of ATP splitting. Embedded in the former phase concept, the term "phase III" was introduced by Ishikawa in 1992 for drug export by ABC efflux pumps. SLC comprise 52 families, from which many carriers are drug uptake transporters. Later on, this uptake process was referred to as the "phase 0 transport" of drugs. Transporters for xenobiotics in man and animal are most expressed in liver, but they are also present in extra-hepatic tissues such as in the kidney, the adrenal gland and lung. This review deals with the function of drug carriers in various organs and their impact on drug metabolism and elimination.
ERIS: preliminary design phase overview
Kuntschner, Harald; Jochum, Lieselotte; Amico, Paola; Dekker, Johannes K.; Kerber, Florian; Marchetti, Enrico; Accardo, Matteo; Brast, Roland; Brinkmann, Martin; Conzelmann, Ralf D.; Delabre, Bernard A.; Duchateau, Michel; Fedrigo, Enrico; Finger, Gert; Frank, Christoph; Rodriguez, Fernando G.; Klein, Barbara; Knudstrup, Jens; Le Louarn, Miska; Lundin, Lars; Modigliani, Andrea; Müller, Michael; Neeser, Mark; Tordo, Sebastien; Valenti, Elena; Eisenhauer, Frank; Sturm, Eckhard; Feuchtgruber, Helmut; George, Elisabeth M.; Hartl, Michael; Hofmann, Reiner; Huber, Heinrich; Plattner, Markus P.; Schubert, Josef; Tarantik, Karl; Wiezorrek, Erich; Meyer, Michael R.; Quanz, Sascha P.; Glauser, Adrian M.; Weisz, Harald; Esposito, Simone; Xompero, Marco; Agapito, Guido; Antichi, Jacopo; Biliotti, Valdemaro; Bonaglia, Marco; Briguglio, Runa; Carbonaro, Luca; Cresci, Giovanni; Fini, Luca; Pinna, Enrico; Puglisi, Alfio T.; Quirós-Pacheco, Fernando; Riccardi, Armando; Di Rico, Gianluca; Arcidiacono, Carmelo; Dolci, Mauro
2014-07-01
The Enhanced Resolution Imager and Spectrograph (ERIS) is the next-generation adaptive optics near-IR imager and spectrograph for the Cassegrain focus of the Very Large Telescope (VLT) Unit Telescope 4, which will soon make full use of the Adaptive Optics Facility (AOF). It is a high-Strehl AO-assisted instrument that will use the Deformable Secondary Mirror (DSM) and the new Laser Guide Star Facility (4LGSF). The project has been approved for construction and has entered its preliminary design phase. ERIS will be constructed in a collaboration including the Max- Planck Institut für Extraterrestrische Physik, the Eidgenössische Technische Hochschule Zürich and the Osservatorio Astrofisico di Arcetri and will offer 1 - 5 μm imaging and 1 - 2.5 μm integral field spectroscopic capabilities with a high Strehl performance. Wavefront sensing can be carried out with an optical high-order NGS Pyramid wavefront sensor, or with a single laser in either an optical low-order NGS mode, or with a near-IR low-order mode sensor. Due to its highly sensitive visible wavefront sensor, and separate near-IR low-order mode, ERIS provides a large sky coverage with its 1' patrol field radius that can even include AO stars embedded in dust-enshrouded environments. As such it will replace, with a much improved single conjugated AO correction, the most scientifically important imaging modes offered by NACO (diffraction limited imaging in the J to M bands, Sparse Aperture Masking and Apodizing Phase Plate (APP) coronagraphy) and the integral field spectroscopy modes of SINFONI, whose instrumental module, SPIFFI, will be upgraded and re-used in ERIS. As part of the SPIFFI upgrade a new higher resolution grating and a science detector replacement are envisaged, as well as PLC driven motors. To accommodate ERIS at the Cassegrain focus, an extension of the telescope back focal length is required, with modifications of the guider arm assembly. In this paper we report on the status of the
Phase balancing optimization for radial feeder systems
Zhu, Jinxiang
In the power distribution systems, unbalanced feeder causes deteriorating power quality and increases investment and operating costs. There are two approaches to balance a feeder system. One approach is feeder reconfiguration, the other is phase swapping. Feeder reconfiguration is an on-line operation of sectionalizing switches. However, feeder reconfiguration is difficult to find the phase balancing solution for a unbalanced feeder system. On the other hand, phase swapping is a direct and effective approach for phase balancing. Phase swapping is an off-line operation of re-tapping loads/laterals to the phase lines during maintenance and restoration periods. Unfortunately, phase balancing problem has not received its deserved importance. Deregulation in power industry has arisen phase balancing issue because it can improve power quality, improve service reliability, and reduce total costs. Thus, phase balancing can enhance utility competitive capability. This research provides utilities the optimization tools to maximize the benefits of phase balancing and minimize the costs. This dissertation proposed several mathematical formulations, including Mixed-integer programming (MIP), Dynamic programming (DP), Simulated annealing (SA), and Fuzzy logic (FL), to perform phase swapping to balance phase in a radial feeder. Due to the discrete nature of phase swapping, a MIP model is proposed to find the optimal phase swapping scheme for small-sized feeder. Candidate sets and monitored branches are then introduced to solve the large-scale feeder systems. Possibilistic integer programming (PIP) is proposed to incorporate load uncertainties in phase swapping problems. The tests show that the load uncertainties may change the optimal phase swapping. DP computation is significant reduced by introducing the tighter upper/lower bounds. The upper bound can be quickly obtained by assignment algorithm. Even though SA is a time-consuming heuristic method, it can provide better solution
Phase Diagram in Quantum Chromodynamics
Apostol, M
2013-01-01
It is suggested that the hadronization of the quark-gluon plasma is a first-order phase transition described by a critical curve in the temperature-(quark) density plane which terminates in a critical point. Such a critical curve is derived from the van der Waals equation and its parameters are estimated by using the theoretical approach given in M. Apostol, Roum. Reps. Phys. 59 249 (2007); Mod. Phys. Lett. B21 893 (2007). The main assumption is that quark-gluon plasma created by high-energy nucleus-nucleus collisions is a gas of ultrarelativistic quarks in equilibrium with gluons (vanishing chemical potential, indefinite number of quarks). This plasma expands, gets cool and dilute and hadronizes at a certain transition temperature and transition density. The transition density is very close to the saturation density of the nuclear matter and, it is suggested that both these points are very close to the critical point n~1fm^{-3} (quark density) and T~200MeV (temperature).
Quantitative ultrasonic phased array imaging
Engle, Brady J.; Schmerr, Lester W., Jr.; Sedov, Alexander
2014-02-01
When imaging with ultrasonic phased arrays, what do we actually image? What quantitative information is contained in the image? Ad-hoc delay-and-sum methods such as the synthetic aperture focusing technique (SAFT) and the total focusing method (TFM) fail to answer these questions. We have shown that a new quantitative approach allows the formation of flaw images by explicitly inverting the Thompson-Gray measurement model. To examine the above questions, we have set up a software simulation test bed that considers a 2-D scalar scattering problem of a cylindrical inclusion with the method of separation of variables. It is shown that in SAFT types of imaging the only part of the flaw properly imaged is the front surface specular response of the flaw. Other responses (back surface reflections, creeping waves, etc.) are improperly imaged and form artifacts in the image. In the case of TFM-like imaging the quantity being properly imaged is an angular integration of the front surface reflectivity. The other, improperly imaged responses are also averaged, leading to a reduction in some of the artifacts present. Our results have strong implications for flaw sizing and flaw characterization with delay-and-sum images.
Photovoltaic manufacturing technology, Phase 1
Energy Technology Data Exchange (ETDEWEB)
1992-10-01
This report describes subcontracted research by the Chronar Corporation, prepared by Advanced Photovoltaic Systems, Inc. (APS) for Phase 1 of the Photovoltaic Manufacturing Technology Development project. Amorphous silicon is chosen as the PV technology that Chronar Corporation and APS believe offers the greatest potential for manufacturing improvements, which, in turn, will result in significant cost reductions and performance improvements in photovoltaic products. The APS Eureka'' facility was chosen as the manufacturing system that can offer the possibility of achieving these production enhancements. The relationship of the Eureka'' facility to Chronar's batch'' plants is discussed. Five key areas are also identified that could meet the objectives of manufacturing potential that could lead to improved performance, reduced manufacturing costs, and significantly increased production. The projected long-term potential benefits of these areas are discussed, as well as problems that may impede the achievement of the hoped-for developments. A significant number of the problems discussed are of a generic nature and could be of general interest to the industry. The final section of this document addresses the cost and time estimates for achieving the solutions to the problems discussed earlier. Emphasis is placed on the number, type, and cost of the human resources required for the project.
Pure Phase Solubility Limits: LANL
Energy Technology Data Exchange (ETDEWEB)
C. Stockman
2001-01-26
The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility
Phase transitions of quadrupolar fluids
O'Shea, Seamus F.; Dubey, Girija S.; Rasaiah, Jayendran C.
1997-07-01
Gibbs ensemble simulations are reported for Lennard-Jones particles with embedded quadrupoles of strength Q*=Q/(ɛσ5)1/2=2.0 where ɛ and σ are the Lennard-Jones parameters. Calculations revealing the effect of the dispersive forces on the liquid-vapor coexistence were carried out by scaling the attractive r-6 term in the Lennard-Jones pair potential by a factor λ ranging from 0 to 1. Liquid-vapor coexistence is observed for all values of λ including λ=0 for Q*=2.0, unlike the corresponding dipolar fluid studied by van Leeuwen and Smit et al. [Phys. Rev. Lett. 71, 3991 (1993)] which showed no phase transition below λ=0.35 when the reduced dipole moment μ*=2.0. The simulation data are analyzed to estimate the critical properties of the quadrupolar fluid and their dependence on the strength λ of the dispersive force. The critical temperature and pressure show a clear quadratic dependence on λ, while the density is less confidently identified as being linear in λ. The compressibility is roughly linear in λ.
Brookner, Eli, Dr.
1988-12-01
Large phased-array radars can play a very important part in arms control. They can be used to determine the number of RVs being deployed, the type of targeting of the RVs (the same or different targets), the shape of the deployed objects, and possibly the weight and yields of the deployed RVs. They can provide this information at night as well as during the day and during rain and cloud covered conditions. The radar can be on the ground, on a ship, in an airplane, or space-borne. Airborne and space-borne radars can provide high resolution map images of the ground for reconnaissance, of anti-ballistic missile (ABM) ground radar installations, missile launch sites, and tactical targets such as trucks and tanks. The large ground based radars can have microwave carrier frequencies or be at HF (high frequency). For a ground-based HF radar the signal is reflected off the ionosphere so as to provide over-the-horizon (OTH) viewing of targets. OTH radars can potentially be used to monitor stealth targets and missile traffic.
Gaseous phase coal surface modification
Energy Technology Data Exchange (ETDEWEB)
Okoh, J.M.; Pinion, J.; Thiensatit, S.
1992-05-07
In this report, we present an improved, feasible and potentially cost effective method of cleaning and beneficiating ultrafine coal. Increased mechanization of mining methods and the need towards depyritization, and demineralization have led to an increase in the quantity of coal fines generated in recent times. For example, the amount of {minus}100 mesh coal occurring in coal preparation plant feeds now typically varies from 5 to 25% of the total feed. Environmental constraints coupled with the greatly increased cost of coal have made it increasingly important to recover more of these fines. Our method chemically modifies the surface of such coals by a series of gaseous phase treatments employing Friedel-Crafts reactions. By using olefins (ethene, propene and butene) and hydrogen chloride catalyst at elevated temperature, the surface hydrophobicity of coal is enhanced. This increased hydrophobicity is manifest in surface phenomena which reflect conditions at the solid/liquid interphase (zeta potential) and those which reflect conditions at the solid/liquid/gas interphases (contact angle, wettability and floatability).
Flexible Ultrasonic Phased-Array Probe
Institute of Scientific and Technical Information of China (English)
施克仁; 阙开良; 郭大勇
2004-01-01
In ultrasonic phased-array testing, most probes are rigid with fixed elements. However, when testing a cambered piece, a rigid probe cannot be used directly, but an ultrasonic chock or coupling media must be used, which adds cost and reduces the accuracy. The objective of this research was to improve the tests of cambered pieces. A flexible ultrasonic phased-array probe was developed to do the flexible phased-array testing. The key technologies in the flexible phased-array probe include the probe design and the phased-array control. A new method was developed to design the flexible probe according to the curvature of the piece and the test depth. The method includes the calculation of the element's height (he), the relative rotation angle ((e), the distance between the adjoining elements (de), and the element's effective testing range. A flexible ultrasonic phased-array probe has been developed using this method.
Novel 3-Phase Inductive Fault Current Limiter
Kosa, Janos
The paper describes the inductive three-phase fault current limiter. In this work I examine the novel arrangements of the perfect closed superconducting loop made of HTS wire. I applied one iron core with 3 limbs and special loops for uniform temperature of the superconducting wire. In this work I present the results of my experiments with this device. I present the static and dynamic measured results of this solution. It has got several advantages e. g. fast switching and less fault power for high-power electric machines. The advantage of the equipment is that in the case of single-phase short circuit the current will decrease in all the three phases. This can be an appropriate solution for high power machines. For example, in the case of high-power electric motor if there is a single-phase breaking or a single phase short circuit, we can decrease the current in the three phases.
Phases of Kaluza-Klein Black Holes
DEFF Research Database (Denmark)
Harmark, Troels; Obers, N. A.
2005-01-01
We review the latest progress in understanding the phase structure of static and neutral Kaluza-Klein black holes, i.e. static and neutral solutions of pure gravity with an event horizon that asymptote to a d-dimensional Minkowski-space times a circle. We start by reviewing the (mu,n) phase diagram...... and the split-up of the phase structure into solutions with an internal SO(d-1) symmetry and solutions with Kaluza-Klein bubbles. We then discuss the uniform black string, non-uniform black string and localized black hole phases, and how those three phases are connected, involving issues such as classical...... instability and horizon-topology changing transitions. Finally, we review the bubble-black hole sequences, their place in the phase structure and interesting aspects such as the continuously infinite non-uniqueness of solutions for a given mass and relative tension....
Phase diagram of a single lane roundabout
Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.
2016-03-01
Using the cellular automata model, we numerically study the traffic dynamic in a single lane roundabout system of four entry/exit points. The boundaries are controlled by the injecting rates α1, α2 and the extracting rate β. Both the system with and without Splitter Islands of width Lsp are considered. The phase diagram in the (α1 , β) space and its variation with the roundabout size, Pagg (i.e. the probability of aggressive entry), and Pexit (i.e. the probability of preferential exit) are constructed. The results show that the phase diagram in both cases consists of three phases: free flow, congested and jammed. However, as Lsp increases the free flow phase enlarges while the congested and jammed ones shrink. On the other hand, the short sized roundabout shows better performance in the free flow phase while the large one is more optimal in the congested phase. The density profiles are also investigated.
A wavelet phase filter for emission tomography
Energy Technology Data Exchange (ETDEWEB)
Olsen, E.T.; Lin, B. [Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Mathematics
1995-07-01
The presence of a high level of noise is a characteristic in some tomographic imaging techniques such as positron emission tomography (PET). Wavelet methods can smooth out noise while preserving significant features of images. Mallat et al. proposed a wavelet based denoising scheme exploiting wavelet modulus maxima, but the scheme is sensitive to noise. In this study, the authors explore the properties of wavelet phase, with a focus on reconstruction of emission tomography images. Specifically, they show that the wavelet phase of regular Poisson noise under a Haar-type wavelet transform converges in distribution to a random variable uniformly distributed on [0, 2{pi}). They then propose three wavelet-phase-based denoising schemes which exploit this property: edge tracking, local phase variance thresholding, and scale phase variation thresholding. Some numerical results are also presented. The numerical experiments indicate that wavelet phase techniques show promise for wavelet based denoising methods.
Phase Variation of Earthshine Polarization Spectra
Takahashi, Jun; Akitaya, Hiroshi; Okazaki, Akira; Kawabata, Koji; Oasa, Yumiko; Isogai, Mizuki
2013-01-01
We present the results of the optical spectropolarimetry of Earthshine on the Moon for Earth phase angles ranging from 49 to 96 degrees. The observations were conducted on 2011 March 9-13 (UT) using the spectropolarimeter HBS installed on the 1.88 m telescope at Okayama Astrophysical Observatory. The wavelength coverage was 450-850 nm with a resolution of 6 nm. The observed Earthshine polarization degree spectra exhibit decreasing polarization degree with increasing wavelength at any phase. The overall degree of polarization increases as the Earth approaches a quadrature phase. The phase dependence differs with the wavelengths; the maximum polarization for the V band occurs at a phase angle of ~90 degrees, whereas that for longer wavelengths is reached at larger phase angles. This is interpreted as indicating that Earthshine polarization at shorter wavelengths is dominated by atmospheric Rayleigh scattering, whereas that at longer wavelengths has an increasingly effective contribution from the Earth surface r...
Phase shifter for antenna beam steering
Jindal, Ravi; Razban, Tchanguiz
2016-03-01
Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.
Experimental study on phase perception in speech
Institute of Scientific and Technical Information of China (English)
BU Fanliang; CHEN Yanpu
2003-01-01
As the human ear is dull to the phase in speech, little attention has been paid tophase information in speech coding. In fact, the speech perceptual quality may be degeneratedif the phase distortion is very large. The perceptual effect of the STFT (Short time Fouriertransform) phase spectrum is studied by auditory subjective hearing tests. Three main con-clusions are (1) If the phase information is neglected completely, the subjective quality of thereconstructed speech may be very poor; (2) Whether the neglected phase is in low frequencyband or high frequency band, the difference from the original speech can be perceived by ear;(3) It is very difficult for the human ear to perceive the difference of speech quality betweenoriginal speech and reconstructed speech while the phase quantization step size is shorter thanπ/7.
Generalised phase contrast: microscopy, manipulation and more
DEFF Research Database (Denmark)
Palima, Darwin; Glückstad, Jesper
2010-01-01
Generalised phase contrast (GPC) not only leads to more accurate phase imaging beyond thin biological samples, but serves as an enabling framework in developing tools over a wide spectrum of contemporary applications in optics and photonics, including optical trapping and micromanipulation, optic...... phase cryptography, light-efficient image projection and parallel laser beam shaping for optical landscapes. In this review, we discuss the fundamental ideas behind generalised phase contrast and present a survey of its exciting applications.......Generalised phase contrast (GPC) not only leads to more accurate phase imaging beyond thin biological samples, but serves as an enabling framework in developing tools over a wide spectrum of contemporary applications in optics and photonics, including optical trapping and micromanipulation, optical...
T phase observations in global seismogram stacks
Buehler, J. S.; Shearer, P. M.
2015-08-01
The T phase, conversion of acoustic to seismic energy, is typically observed as a high-frequency wave train at hydrophones or coastal seismic stations. Here we show that the T phase can be observed in broadband waveform stacks of ˜5200 earthquakes recorded by the Global Seismic Network. To enhance the phase arrivals in stacks, we apply short-time window average over long-time window average filtering to individual traces before stacking. Although the T phase arrival is visible in stacks from seismograms filtered at 0.5-5 Hz, it appears much stronger at higher frequencies (2-8 Hz) and is further enhanced by only stacking seismograms from oceanic paths. Stacking only subsets of the data depending on continental path lengths on the receiver side shows that the T phase can be observed at stations up to 4∘ inland from the coast, and changes in the T phase arrival time correspond to reasonable crustal velocities.
Phase shifter for antenna beam steering
Energy Technology Data Exchange (ETDEWEB)
Jindal, Ravi, E-mail: rjindal21@gmail.com [Master’s(MS) in System Electronics and General Electrical, Ecole Polytechnique of university of Nantes France, IETR, Nantes (France); Razban, Tchanguiz, E-mail: tchanguiz.razban-haghighi@univ-nantes.fr [Electronics and Telecommunication Institute of Rennes (IETR-UMR 6164), Ecole Polytechnique of university of Nantes France, IETR, Nantes (France)
2016-03-09
Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.
Chiral Liquid Crystals: Structures, Phases, Effects
Directory of Open Access Journals (Sweden)
Ingo Dierking
2014-06-01
Full Text Available The introduction of chirality, i.e., the lack of mirror symmetry, has a profound effect on liquid crystals, not only on the molecular scale but also on the supermolecular scale and phase. I review these effects, which are related to the formation of supermolecular helicity, the occurrence of novel thermodynamic phases, as well as electro-optic effects which can only be observed in chiral liquid crystalline materials. In particular, I will discuss the formation of helical superstructures in cholesteric, Twist Grain Boundary and ferroelectric phases. As examples for the occurrence of novel phases the Blue Phases and Twist Grain Boundary phases are introduced. Chirality related effects are demonstrated through the occurrence of ferroelectricity in both thermotropic as well as lyotropic liquid crystals. Lack of mirror symmetry is also discussed briefly for some biopolymers such as cellulose and DNA, together with its influence on liquid crystalline behavior.
Phase slips in superconducting weak links
Energy Technology Data Exchange (ETDEWEB)
Kimmel, Gregory; Glatz, Andreas; Aranson, Igor S.
2017-01-01
Superconducting vortices and phase slips are primary mechanisms of dissipation in superconducting, superfluid, and cold-atom systems. While the dynamics of vortices is fairly well described, phase slips occurring in quasi-one- dimensional superconducting wires still elude understanding. The main reason is that phase slips are strongly nonlinear time-dependent phenomena that cannot be cast in terms of small perturbations of the superconducting state. Here we study phase slips occurring in superconducting weak links. Thanks to partial suppression of superconductivity in weak links, we employ a weakly nonlinear approximation for dynamic phase slips. This approximation is not valid for homogeneous superconducting wires and slabs. Using the numerical solution of the time-dependent Ginzburg-Landau equation and bifurcation analysis of stationary solutions, we show that the onset of phase slips occurs via an infinite period bifurcation, which is manifested in a specific voltage-current dependence. Our analytical results are in good agreement with simulations.
A MODEL FOR PREDICTING PHASE INVERSION IN OIL-WATER TWO-PHASE PIPE FLOW
Institute of Scientific and Technical Information of China (English)
GONG Jing; LI Qing-ping; YAO Hai-yuan; YU Da
2006-01-01
Experiments of phase inversion characteristics for horizontal oil-water two-phase flow in a stainless steel pipe loop (25.7 mm inner diameter,52 m long) are conducted. A new viewpoint is brought forward about the process of phase inversion in oil-water two-phase pipe flow. Using the relations between the total free energies of the pre-inversion and post-inversion dispersions, a model for predicting phase inversion in oil-water two-phase pipe flow has been developed that considers the characteristics of pipe flow. This model is compared against other models with relevant data of phase inversion in oil-water two-phase pipe flow. Results indicate that this model is better than other models in terms of calculation precision and applicability. The model is useful for guiding the design for optimal performance and safety in the operation of oil-water two-phase pipe flow in oil fields.
Phase-sensitive fat suppression steady-state free procession sequence with phase correction
Institute of Scientific and Technical Information of China (English)
Zu Zhong-Liang; Zhou Kun; Zhang Shi-Gang; Gao Song; Bao Shang-Lian
2008-01-01
Robust and fast fat suppression is a challenge in balanced steady-state free precession (SSFP) magnetic resonance imaging.Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time,phase errors,especially spatially-dependent phase shift,caused by a variety of factors may result in misplacement of fat and water voxels.In this paper,a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction.This algorithm corrects phase by region growing,employing both the magnitude and the phase information of image pixels.Phantom and in vivo imagings were performed to validate the technique.As a result,excellent fat-suppressed images were acquired by using single-acquisition phase-seusitive SSFP with phase correction.
Phase shifting interferometry from two normalized interferograms with random tilt phase-shift.
Liu, Fengwei; Wu, Yongqian; Wu, Fan
2015-07-27
We propose a novel phase shifting interferometry from two normalized interferograms with random tilt phase-shift. The determination of tilt phase-shift is performed by extracting the tilted phase-shift plane from the phase difference of two normalized interferograms, and with the calculated tilt phase-shift value the phase distribution can be retrieved from the two normalized frames. By analyzing the distribution of phase difference and utilizing special points fitting method, the tilted phase-shift plane is extracted in three different cases, which relate to different magnitudes of tilts. Proposed method has been applied to simulations and experiments successfully and the satisfactory results manifest that proposed method is of high accuracy and high speed compared with the three step iterative method. Additionally, both open and closed fringe can be analyzed with proposed method. What's more, it cannot only eliminate the small tilt-shift error caused by slight vibration in phase-shifting interferometry, but also detect the large tilt phase-shift in phase-tilting interferometry. Thus, it will relaxes the requirements on the accuracy of phase shifter, and the costly phase shifter may even be useless by applying proposed method in high amplitude vibrated circumstance to achieve high-precision analysis.
Classifying the Quantum Phases of Matter
2015-01-01
2013), arXiv:1305.2176. [10] J. Haah, Lattice quantum codes and exotic topological phases of matter , arXiv:1305.6973. [11[ M. Hastings and S...CLASSIFYING THE QUANTUM PHASES OF MATTER CALIFORNIA INSTITUTE OF TECHNOLOGY JANUARY 2015 FINAL TECHNICAL REPORT...REPORT 3. DATES COVERED (From - To) JAN 2012 – AUG 2014 4. TITLE AND SUBTITLE CLASSIFYING THE QUANTUM PHASES OF MATTER 5a. CONTRACT NUMBER FA8750-12-2
A number-phase Wigner function
Energy Technology Data Exchange (ETDEWEB)
Moya-Cessa, Hector [INAOE, Coordinacion de Optica, Apartado Postal 51 y 216, 72000 Puebla, Puebla (Mexico)
2003-06-01
One of the most prominent quasiprobability functions in quantum mechanics is the Wigner function, which gives the correct marginal probability functions if integrated over position or momentum. Here we depart from the definition of the position-momentum Wigner function to, by analogy, construct a number-phase Wigner function that, if summed over photon numbers, gives the correct phase distribution and, if integrated over phase, gives the correct photon distribution.
In-line phase shift tomosynthesis
Energy Technology Data Exchange (ETDEWEB)
Hammonds, Jeffrey C.; Price, Ronald R.; Pickens, David R.; Donnelly, Edwin F. [Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232 (United States)
2013-08-15
Purpose: The purpose of this work is to (1) demonstrate laboratory measurements of phase shift images derived from in-line phase-contrast radiographs using the attenuation-partition based algorithm (APBA) of Yan et al.[Opt. Express 18(15), 16074–16089 (2010)], (2) verify that the APBA reconstructed images obey the linearity principle, and (3) reconstruct tomosynthesis phase shift images from a collection of angularly sampled planar phase shift images.Methods: An unmodified, commercially available cabinet x-ray system (Faxitron LX-60) was used in this experiment. This system contains a tungsten anode x-ray tube with a nominal focal spot size of 10 μm. The digital detector uses CsI/CMOS with a pixel size of 50 × 50 μm. The phantoms used consisted of one acrylic plate, two polystyrene plates, and a habanero pepper. Tomosynthesis images were reconstructed from 51 images acquired over a ±25° arc. All phase shift images were reconstructed using the APBA.Results: Image contrast derived from the planar phase shift image of an acrylic plate of uniform thickness exceeded the contrast of the traditional attenuation image by an approximate factor of two. Comparison of the planar phase shift images from a single, uniform thickness polystyrene plate with two polystyrene plates demonstrated an approximate linearity of the estimated phase shift with plate thickness (−1600 rad vs −2970 rad). Tomographic phase shift images of the habanero pepper exhibited acceptable spatial resolution and contrast comparable to the corresponding attenuation image.Conclusions: This work demonstrated the feasibility of laboratory-based phase shift tomosynthesis and suggests that phase shift imaging could potentially provide a new imaging biomarker. Further investigation will be needed to determine if phase shift contrast will be able to provide new tissue contrast information or improved clinical performance.
Marijan Jurgo
2013-01-01
The paper reviews working principles of phase-locked loop and drawbacks of classical PLL structure in nanometric technologies. It is proposed to replace the classical structure by all-digital phase-locked loop structure. Authors described the main blocks of all-digital phase-locked loop (time to digital converter and digitally controlled oscillator) and overviewed the quantization noise arising in these blocks as well as its minimization strategies. The calculated inverter delay in 65 nm CMOS...
Cosmological phase transitions from lattice field theory
Energy Technology Data Exchange (ETDEWEB)
Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-11-22
In this proceedings contribution we discuss the fate of the electroweak and the quantum chromodynamics phase transitions relevant for the early stage of the universe at non-zero temperature. These phase transitions are related to the Higgs mechanism and the breaking of chiral symmetry, respectively. We will review that non-perturbative lattice field theory simulations show that these phase transitions actually do not occur in nature and that physical observables show a completely smooth behaviour as a function of the temperature.
Approximately liner phase IIR digital filter banks
J. D. Ćertić; M. D. Lutovac; L. D. Milić
2013-01-01
In this paper, uniform and nonuniform digital filter banks based on approximately linear phase IIR filters and frequency response masking technique (FRM) are presented. Both filter banks are realized as a connection of an interpolated half-band approximately linear phase IIR filter as a first stage of the FRM design and an appropriate number of masking filters. The masking filters are half-band IIR filters with an approximately linear phase. The resulting IIR filter banks are compared with li...
Phase distribution in complex geometry conduits
Energy Technology Data Exchange (ETDEWEB)
Lahey, R.T. Jr.; Lopez de Bertodano, M.; Jones, O.C. Jr.
1992-12-31
Some of the most important and challenging problems in two-phase flow today have to do with the understanding and prediction of multidimensional phenomena, in particular, lateral phase distribution in both simple and complex geometry conduits. A prior review paper summarized the state-of-the-art in the understanding of phase distribution phenomena, and the ability to perform mechanistic multidimensional predictions. The purpose of this paper is to update that review, with particular emphasis on complex geometry conduit predictive capabilities.
Stationary phase deposition based on onium salts
Wheeler, David R.; Lewis, Patrick R.; Dirk, Shawn M.; Trudell, Daniel E.
2008-01-01
Onium salt chemistry can be used to deposit very uniform thickness stationary phases on the wall of a gas chromatography column. In particular, the stationary phase can be bonded to non-silicon based columns, especially microfabricated metal columns. Non-silicon microfabricated columns may be manufactured and processed at a fraction of the cost of silicon-based columns. In addition, the method can be used to phase-coat conventional capillary columns or silicon-based microfabricated columns.
On Phases of Generic Toric Singularities
Sarkar, Tapobrata
2007-01-01
We systematically study the phases of generic toric singularities, using methods initiated in hep-th/0612046. These correspond to Gauged Linear Sigma Models with arbitrary charges. We show that complete information about generic $U(1)^r$ GLSMs can be obtained by studying the GLSM Lagrangian, appropriately modified in the different phases of the theory. This can be used to study the different phases of $L^{a,b,c}$ spaces and their non-supersymmetric counterparts.
Economical Phase-Covariant Cloning of Qudits
Buscemi, F; Macchiavello, C; Buscemi, Francesco; Ariano, Giacomo Mauro D'; Macchiavello, Chiara
2004-01-01
We derive the optimal $N\\to M$ phase-covariant quantum cloning for equatorial states in dimension $d$ with $M=kd+N$, $k$ integer. The cloning maps are optimal for both global and single-qudit fidelity. The map is achieved by an ``economical'' cloning machine, which works without ancilla. The connection between optimal phase-covariant cloning and optimal multi-phase estimation is finally established.
Micro-Texture Synthesis by Phase Randomization
Directory of Open Access Journals (Sweden)
Bruno Galerne
2011-09-01
Full Text Available This contribution is concerned with texture synthesis by example, the process of generating new texture images from a given sample. The Random Phase Noise algorithm presented here synthesizes a texture from an original image by simply randomizing its Fourier phase. It is able to reproduce textures which are characterized by their Fourier modulus, namely the random phase textures (or micro-textures.
Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria
Energy Technology Data Exchange (ETDEWEB)
Park, Jung Jae; Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of)
2016-10-15
To retrospectively evaluate the diagnostic performance of single-phase dual-energy CT (DECT) with virtual non-contrast CT (VNCT) compared with three-phase CT urography (CTU) in patients with haematuria. A total of 296 patients underwent three-phase CTU (NCT at 120 kVp; nephrographic phase and excretory phase DECTs at 140 kVp and 80 kVp) owing to haematuria. Diagnostic performances of CT scans were compared for detecting urothelial tumours and urinary stones. Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU. Sensitivity and specificity for tumour were 95 % (19/20) and 98.9 % (273/276) on CTU, 95 % (19/20) and 98.2 % (271/276) on nephrographic phase DECT, and 90 % (18/20) and 98.2 % (271/276) on excretory phase DECT (P > 0.1). Of the 148 stones detected on NCT, 108 (73 %) and 100 (67.6 %) were detected on nephrographic phase and excretory phase VNCTs, respectively. The mean size of stones undetected on nephrographic and excretory VNCTs was measured as 1.5 ± 0.5 mm and 1.6 ± 0.6 mm, respectively. The mean DLPs of three-phase CTU, nephrographic phase DECT and excretory phase DECT were 1076 ± 248 mGy . cm, 410 ± 98 mGy . cm, and 360 ± 87 mGy . cm, respectively (P < 0.001). Single-phase DECT has a potential to replace three-phase CTU for detecting tumours with a lower radiation dose. (orig.)
Institute of Scientific and Technical Information of China (English)
LU Xiaoxu; ZHONG Liyun; ZHANG Yimo
2007-01-01
Phase-shifting measurement and its error estimation method were studied according to the holographic principle.A function of synchronous superposition of object complex amplitude reconstructed from N-step phase-shifting through one integral period (N-step phase-shifting function for short) was proposed.In N-step phase-shifting measurement,the interferograms are seen as a series of in-line holograms and the reference beam is an ideal parallel-plane wave.So the N-step phase-shifting function can be obtained by multiplying the interferogram by the original referencc wave.In ideal conditions.the proposed method is a kind of synchronous superposition algorithm in which the complex amplitude is separated,measured and superposed.When error exists in measurement,the result of the N-step phase-shifting function is the optimal expected value of the least-squares fitting method.In the above method,the N+1-step phase-shifting function can be obtained from the N-step phase-shifting function.It shows that the N-step phase-shifting function can be separated into two parts:the ideal N-step phase-shifting function and its errors.The phase-shifting errors in N-steps phase-shifting phase measurement can be treated the same as the relative errors of amplitude and intensity under the understanding of the N+1-step phase-shifting function.The difficulties of the error estimation in phase-shifting phase measurement were restricted by this error estimation method.Meanwhile,the maximum error estimation method of phase-shifting phase measurement and its formula were proposed.
Using phase II data for the analysis of phase III studies: An application in rare diseases.
Wandel, Simon; Neuenschwander, Beat; Röver, Christian; Friede, Tim
2017-06-01
Clinical research and drug development in orphan diseases are challenging, since large-scale randomized studies are difficult to conduct. Formally synthesizing the evidence is therefore of great value, yet this is rarely done in the drug-approval process. Phase III designs that make better use of phase II data can facilitate drug development in orphan diseases. A Bayesian meta-analytic approach is used to inform the phase III study with phase II data. It is particularly attractive, since uncertainty of between-trial heterogeneity can be dealt with probabilistically, which is critical if the number of studies is small. Furthermore, it allows quantifying and discounting the phase II data through the predictive distribution relevant for phase III. A phase III design is proposed which uses the phase II data and considers approval based on a phase III interim analysis. The design is illustrated with a non-inferiority case study from a Food and Drug Administration approval in herpetic keratitis (an orphan disease). Design operating characteristics are compared to those of a traditional design, which ignores the phase II data. An analysis of the phase II data reveals good but insufficient evidence for non-inferiority, highlighting the need for a phase III study. For the phase III study supported by phase II data, the interim analysis is based on half of the patients. For this design, the meta-analytic interim results are conclusive and would justify approval. In contrast, based on the phase III data only, interim results are inconclusive and require further evidence. To accelerate drug development for orphan diseases, innovative study designs and appropriate methodology are needed. Taking advantage of randomized phase II data when analyzing phase III studies looks promising because the evidence from phase II supports informed decision-making. The implementation of the Bayesian design is straightforward with public software such as R.
Energy Technology Data Exchange (ETDEWEB)
Lider, V. V., E-mail: lider@ns.crys.ras.ru; Kovalchuk, M. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
2013-11-15
This review is devoted to a comparative description of the methods for forming X-ray phase-contrast images of weakly absorbing (phase) objects. These include the crystal interferometer method, the Talbot interferometer method, diffraction-enhanced X-ray imaging, and the in-line method. The potential of their practical application in various fields of science and technology is discussed. The publications on the development and optimization of X-ray phase-contrast methods and the experimental study of phase objects are analyzed.
Unwrapped phase inversion with an exponential damping
Choi, Yun Seok
2015-07-28
Full-waveform inversion (FWI) suffers from the phase wrapping (cycle skipping) problem when the frequency of data is not low enough. Unless we obtain a good initial velocity model, the phase wrapping problem in FWI causes a result corresponding to a local minimum, usually far away from the true solution, especially at depth. Thus, we have developed an inversion algorithm based on a space-domain unwrapped phase, and we also used exponential damping to mitigate the nonlinearity associated with the reflections. We construct the 2D phase residual map, which usually contains the wrapping discontinuities, especially if the model is complex and the frequency is high. We then unwrap the phase map and remove these cycle-based jumps. However, if the phase map has several residues, the unwrapping process becomes very complicated. We apply a strong exponential damping to the wavefield to eliminate much of the residues in the phase map, thus making the unwrapping process simple. We finally invert the unwrapped phases using the back-propagation algorithm to calculate the gradient. We progressively reduce the damping factor to obtain a high-resolution image. Numerical examples determined that the unwrapped phase inversion with a strong exponential damping generated convergent long-wavelength updates without low-frequency information. This model can be used as a good starting model for a subsequent inversion with a reduced damping, eventually leading to conventional waveform inversion.
The quantum phase operator a review
Barnett, Stephen M
2013-01-01
Describing the phase of an electromagnetic field mode or harmonic oscillator has been an obstacle since the early days of modern quantum theory. The quantum phase operator was even more problematic with the invention of the maser and laser in the 1950s and 1960s. This problem was not solved until the Pegg-Barnett formalism was developed in the 1980s. Edited by one of the scientists who created this key solution, The Quantum Phase Operator: A Review charts the development of phase and angle operators from their first appearance to modern theory. Bringing together vital works that have been publ
Cycle slipping in phase synchronization systems
Yang, Ying; Huang, Lin
2007-02-01
Cycle slipping is a characteristically nonlinear phenomenon in phase synchronization systems, which is highly dependent of the initial state of the system. Slipping a cycle means that the phase error is increased to such an extent that the generator to be synchronized slips one complete cycle with respect to the input phase. In this Letter, a linear matrix inequality (LMI) based approach is proposed and the estimation of the number of cycles which slips a solution of the system is obtained by solving a quasi-convex optimization problem of LMI. Applications to phase locked loops demonstrate the validity of the proposed approach.
Marginal phase correction of truncated Bessel beams
Sedukhin
2000-06-01
Approximate analytic expressions are obtained for evaluating the axial intensity and the central-lobe diameter of J0 Bessel beams transmitted through a finite-aperture phase filter. A reasonable quality factor governing the axial-intensity behavior of a phase-undistorted truncated Bessel beam is found to be the inverse square root of the Fresnel number defined, for a given aperture, from the axial point of geometrical shadow. Additional drastic reduction of axial-intensity oscillations is accomplished by using marginal phase correction of the beam instead of the well-known amplitude apodization. A procedure for analytically calculating an optimal monotonic slowly varying correction phase function is described.
SUSY and the Electroweak Phase Transition
Farrar, Glennys R S; Farrar, Glennys R.; Losada, Marta
1996-01-01
We analyze the effective 3 dimensional theory previously constructed for the MSSM and multi-Higgs models to determine the regions of parameter space in which the electroweak phase transition is sufficiently strong for a $B+L$ asymmetry to survive in the low temperature phase. We find that the inclusion of all supersymmetric scalars and all 1-loop corrections has the effect of enhancing the strength of the phase transition. Without a light stop or extension of the MSSM the phase transition is sufficiently first order only if the lightest Higgs mass $M_{h}\\lsi 70$ GeV and $tan\\beta\\lsi 1.75$.
Phase II clinical development of new drugs
Ting, Naitee; Ho, Shuyen; Cappelleri, Joseph C
2017-01-01
This book focuses on how to appropriately plan and develop a Phase II program, and how to design Phase II clinical trials and analyze their data. It provides a comprehensive overview of the entire drug development process and highlights key questions that need to be addressed for the successful execution of Phase II, so as to increase its success in Phase III and for drug approval. Lastly it warns project team members of the common potential pitfalls and offers tips on how to avoid them.
Binding by asynchrony: the neuronal phase code
Directory of Open Access Journals (Sweden)
Zoltan Nadasdy
2010-09-01
Full Text Available Neurons display continuous subthreshold oscillations and discrete action potentials. When action potentials are phase-locked to the subthreshold oscillation, we hypothesize they represent two types of information: the presence/absence of a sensory feature and the phase of subthreshold oscillation. If subthreshold oscillation phases are neuron-specific, then the sources of action potentials can be recovered based on the action potential times. If the spatial information about the stimulus is converted to action potential phases, then action potentials from multiple neurons can be combined into a single axon and the spatial configuration reconstructed elsewhere. For the reconstruction to be successful, we introduce two assumptions: that a subthreshold oscillation field has a constant phase gradient and that coincidences between action potentials and intracellular subthreshold oscillations are neuron-specific as defined by the "interference principle." Under these assumptions, a phase coding model enables information transfer between structures and reproduces experimental phenomenons such as phase precession, grid cell architecture, and phase modulation of cortical spikes. This article reviews a recently proposed neuronal algorithm for information encoding and decoding from the phase of action potentials (Nadasdy 2009. The focus is given to the principles common across different systems instead of emphasizing system specific differences.
Phase diagrams modified by interfacial penalties
Directory of Open Access Journals (Sweden)
Atanacković T.M.
2007-01-01
Full Text Available The conventional forms of phase diagrams are constructed without consideration of interfacial energies and they represent an important tool for chemical engineers and metallurgists. If interfacial energies are taken into consideration, it is intuitively obvious that the regions of phase equilibria must become smaller, because there is a penalty on the formation of interfaces. We investigate this phenomenon qualitatively for a one-dimensional model, in which the phases occur as layers rather than droplets or bubbles. The modified phase diagrams are shown in Chapters 3 and 4.
When is the deconfinement phase transition universal?
Holland, K; Wiese, U J
2003-01-01
Pure Yang-Mills theory has a finite-temperature phase transition, separating the confined and deconfined bulk phases. Svetitsky and Yaffe conjectured that if this phase transition is of second order, it belongs to the universality class of transitions for particular scalar field theories in one lower dimension. We examine Yang-Mills theory with the symplectic gauge groups Sp(N). We find new evidence supporting the Svetitsky-Yaffe conjecture and make our own conjecture as to which gauge theories have a universal second order deconfinement phase transition.
Enhancing FEL Power with Phase Shifters
Energy Technology Data Exchange (ETDEWEB)
Ratner, Daniel; /Stanford U.; Chao, Alex; Huang, Zhirong; /SLAC
2010-07-30
Tapering the undulator parameter is a well-known method for maintaining the resonant condition past saturation, and increasing Free Electron Laser (FEL) efficiency. In this paper, we demonstrate that shifting the electron bunch phase relative to the radiation is equivalent to tapering the undulator parameter. Using discrete phase changes derived from optimized undulator tapers for the Linac Coherent Light Source (LCLS) x-ray FEL, we show that appropriate phase shifts between undulator sections can reproduce the power enhancement of undulator tapers. Phase shifters are relatively easy to implement and operate, and could be used to aid or replace undulator tapers in optimizing FEL performance.
Synthesis of pure Portland cement phases
DEFF Research Database (Denmark)
Wesselsky, Andreas; Jensen, Ole Mejlhede
2009-01-01
Pure phases commonly found in Portland cement clinkers are often used to test cement hydration behaviour in simplified experimental conditions. The synthesis of these phases is covered in this paper, starting with a description of phase relations and possible polymorphs of the four main phases...... in Portland cement, i.e. tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium alumino ferrite. Details of the The process of solid state synthesis are is described in general including practical advice on equipment and techniques. Finally In addition, some exemplary mix compositions...
Validation of ESO Phase 3 data submissions
Delmotte, N.; Arnaboldi, M.; Mascetti, L.; Micol, A.; Retzlaff, J.
2016-07-01
The data validation phase is an essential step of the Phase 3 process at ESO that is defining and providing an infrastructure to deal with interactions between the data producers and the archive. We are using a controlled process to systematically review all Phase 3 data submissions to ensure a homogeneous and consistent science archive with well traceable and characterised data products, to the benefits of archive users. How the Phase 3 data validation plan is defined and how its results are subsequently managed will be described in the presentation. For a description of its technical implementation, please refer to the contribution by L. Mascetti.
Double acting stirling engine phase control
Berchowitz, David M.
1983-01-01
A mechanical device for effecting a phase change between the expansion and compression volumes of a double-acting Stirling engine uses helical elements which produce opposite rotation of a pair of crankpins when a control rod is moved, so the phase between two pairs of pistons is changed by +.psi. and the phase between the other two pairs of pistons is changed by -.psi.. The phase can change beyond .psi.=90.degree. at which regenerative braking and then reversal of engine rotation occurs.
Macromodel of Precise Signal-Phase Meter
Directory of Open Access Journals (Sweden)
Matej Šalamon
2012-01-01
Full Text Available This paper presents a precise macromodel of a signal-phase meter, which allows continuous phase measurement during simulation. It has been developed as a support tool during the design process of a signal-conditioning circuit for incremental position encoders. The development of a signal conditioning circuit requires precise measurements of small signal phases, amplitudes and offsets using the analog/digital circuit simulator. The phase measurement cannot be performed directly with a simulator, therefore an appropriate macro-model is needed for a circuit simulator. The structure of the signal-phase meter is based on the conventional signal-phase measuring method and is intended for the measuring of a cosine-signal phase with a known frequency. It recommends that the time variations of an input signal’s parameters (amplitude, phase, frequency, and offset voltage are slow and small as possible. Rapid change of a signal’s parameters decreases the simulation result’s accuracy. A macro-model’s precision mainly depends on the chosen parameters for the macro-model and for the simulation. We show that with the proposed meter’s model, the phase angle can be measured with an accuracy of more than ±0,02%.
A Gaussian measure of quantum phase noise
Schleich, Wolfgang P.; Dowling, Jonathan P.
1992-01-01
We study the width of the semiclassical phase distribution of a quantum state in its dependence on the average number of photons (m) in this state. As a measure of phase noise, we choose the width, delta phi, of the best Gaussian approximation to the dominant peak of this probability curve. For a coherent state, this width decreases with the square root of (m), whereas for a truncated phase state it decreases linearly with increasing (m). For an optimal phase state, delta phi decreases exponentially but so does the area caught underneath the peak: all the probability is stored in the broad wings of the distribution.
Oscillating systems with cointegrated phase processes
DEFF Research Database (Denmark)
Østergaard, Jacob; Rahbek, Anders; Ditlevsen, Susanne
2017-01-01
We present cointegration analysis as a method to infer the network structure of a linearly phase coupled oscillating system. By defining a class of oscillating systems with interacting phases, we derive a data generating process where we can specify the coupling structure of a network that resemb......We present cointegration analysis as a method to infer the network structure of a linearly phase coupled oscillating system. By defining a class of oscillating systems with interacting phases, we derive a data generating process where we can specify the coupling structure of a network...
Directory of Open Access Journals (Sweden)
Xiaoyan Lu
2016-10-01
Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.
Optical phase encryption by phase contrast using electrically addressed spatial light modulator
Nishchal, Naveen Kumar; Joseph, Joby; Singh, Kehar
2003-03-01
We report the use of an electrically addressed liquid crystal spatial light modulator (EALCSLM) operating in the phase mode as a phase-contrast filter (PCF). As an application, an optical phase encryption system has been implemented. We encrypt and decrypt a two-dimensional phase image obtained from an amplitude image. Encrypted image is holographically recorded in a Barium titanate crystal and is then decrypted by generating through phase conjugation, a conjugate of the encrypted image. The decrypted phase image is converted into an amplitude image using an EASLM as a PCF. The idea has been supported by the experimental results.
Phase-only spatial light modulation by the reverse phase contrast method
DEFF Research Database (Denmark)
Glückstad, J.; Mogensen, P.C.; Eriksen, R.L.
2002-01-01
A new approach to phase-only spatial light modulation is proposed in which a given amplitude pattern can be converted into a spatially identical binary phase pattern. A spatial filtering approach is applied to transform spatial amplitude modulation into spatial phase modulation using the Reverse...... Phase Contrast (RPC) method. The analytical method for achieving this is outlined and experimental results are shown for the generation of a binary phase-only distribution using an amplitude spatial light modulator and a phase-only spatial filter....
Phase analysis on dual-phase steel using band slope of electron backscatter diffraction pattern.
Kang, Jun-Yun; Park, Seong-Jun; Moon, Man-Been
2013-08-01
A quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite-martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger phase contrast than another conventional one, band contrast. Owing to high sensitivity to lattice defect and little orientation dependence, BS provided handiness in finding a threshold for phase discrimination. Its grain average gave a superior result on the discrimination and volume fraction measurement of the constituent phases in the DP steel.
A novel phase-locking-free phase sensitive amplifier based Regenerator
DEFF Research Database (Denmark)
Kjøller, Niels-Kristian; Røge, Kasper Meldgaard; Guan, Pengyu
2015-01-01
We propose and demonstrate a novel PSK regenerator based on phase sensitive amplification without active phase-locking. The scheme is applied to regenerate a phase noise degraded 10-Gbit/s DPSK signal, improving receiver sensitivity by 3.5 dB.......We propose and demonstrate a novel PSK regenerator based on phase sensitive amplification without active phase-locking. The scheme is applied to regenerate a phase noise degraded 10-Gbit/s DPSK signal, improving receiver sensitivity by 3.5 dB....
Directory of Open Access Journals (Sweden)
Kelley Coffman
2017-01-01
Full Text Available The mainstay treatment of Clostridium difficile infections (CDI is antimicrobials with growing support for fecal microbiota transplants. We report the first case of an elderly man with severe refractory NAP-1 pseudomembranous CDI who failed all medical therapy and two fecal transplants with response only seen after administration of intravenous immunoglobulin.
Four salt phases of theophylline.
Buist, Amanda R; Kennedy, Alan R; Manzie, Craig
2014-02-01
The structures of two anhydrous salt phases of theophylline, namely 1,3-dimethyl-2,6-dioxo-7H-purin-9-ium tetrafluoroborate, C7H9N4O2(+)·BF4(-), and 1,3-dimethyl-2,6-dioxo-7H-purin-9-ium chloride, C7H9N4O2(+)·Cl(-), are reported together with the structures of two monohydrate salt forms, namely 1,3-dimethyl-2,6-dioxo-7H-purin-9-ium chloride monohydrate, C7H9N4O2(+)·Cl(-)·H2O, and 1,3-dimethyl-2,6-dioxo-7H-purin-9-ium bromide monohydrate, C7H9N4O2(+)·Br(-)·H2O. The monohydrate structures are mutually isostructural, with the cations and anions lying on crystallographic mirror planes (Z' = ½). The main intermolecular interaction motif is a hydrogen-bonding network in the same mirror plane. The tetrafluoroborate structure is based on planar hydrogen-bonded theopylline cation dimers; the anions interact with the dimers in a pendant fashion. The anhydrous chloride structure has Z' = 2 and in contrast to the other species it does not form planar hydrogen-bonded constructs, instead one-dimensional chains of cations and anions propagate parallel to the crystallographic c direction. An earlier report claiming to describe an anhydrous structure of theophylline hydrochloride is re-examined in light of these results. It is concluded that the earlier structure has been reported in the wrong space group and that it has been chemically misidentified.
Search of Exoplanets - Phase I
Vodniza, Alberto Q.; Pereira, M. R.; Lopez, J. P.; Reyes, K.; Chaves, L.
2008-09-01
From the Astronomical Observatory at the University of Nariño-COLOMBIA, we have begun a systematic search for exoplanets. Initially we made differential photometry on variable stars weaker than the tenth magnitude to get enough experience on the establishment of stellar transits, so then we could undertake the work with exoplanets. We have already confirmed the transits of two exoplanets with good photometry data: At the exoplanet HAT-P-5b, discovered by Bakos and other investigators and which turns around the GSC 02634-01087, with an orbital period of 2.788491 days according to measurements of the discoverers, and also at the exoplanet TrES-3, discovered by O'Donovan and other investigators and which turns around the GSC 03089-00929, with an orbital period of 1.30619 days, established by its discoverers. Both exoplanets are quite interesting because they have one of the smallest periods found on exoplanets. The TrES-3 also provides a big opportunity for studying the orbital decay and mass loss due to evaporation, caused by the great closeness to its star. We have captured a lot of data to elaborate the lightcurves so we can estimate physical parameters of the bodies. We are getting data on various dates. Actually we are preparing the equipment to develop observations of radial velocities through spectrometry. In a later phase, we expect to verify the presence of other exoplanets which cause less deep transits, and then we can investigate stars with possible exoplanets around them. Besides we hope to design a mathematical model of the studied systems. The equipment we employed is: 14"LX200 GPS MEADE telescope, ST-7XME SBIG camera, STL-1001 SBIG camera, LHIRES III Spectrograph, and SGS-SBIG Spectrograph. On the poster it is explained at length the methodology followed over the search, the data we obtained and the physical- mathematical analysis that was carried out.
Yaqoob, Zahid; Choi, Wonshik; Oh, Seungeun; Lue, Niyom; Park, Yongkeun; Fang-Yen, Christopher; Dasari, Ramachandra R.; Badizadegan, Kamran; Feld, Michael S.
2010-01-01
We report a quantitative phase microscope based on spectral domain optical coherence tomography and line-field illumination. The line illumination allows self phase-referencing method to reject common-mode phase noise. The quantitative phase microscope also features a separate reference arm, permitting the use of high numerical aperture (NA > 1) microscope objectives for high resolution phase measurement at multiple points along the line of illumination. We demonstrate that the path-length sensitivity of the instrument can be as good as 41 pm/Hz, which makes it suitable for nanometer scale study of cell motility. We present the detection of natural motions of cell surface and two-dimensional surface profiling of a HeLa cell. PMID:19550464
MR phase imaging with bipolar acquisition.
Dagher, Joseph; Nael, Kambiz
2017-04-01
We have previously proposed a novel magnetic resonance (MR) phase imaging framework (MAGPI) based on a three-echo sequence that demonstrated substantial gains in phase signal-to-noise ratio (SNR). We improve upon the performance of MAGPI by extending the formulation to handle (i) an alternating gradient polarity (bipolar) readout scheme and (ii) an arbitrary number of echoes. We formulate the phase-imaging problem using maximum-likelihood (ML) estimation. The acquisition uses an optimized multi-echo gradient echo (MEGE) sequence. The tissue-phase estimation algorithm is a voxel-per-voxel approach, which requires no reference scans, no phase unwrapping and no spatial denoising. Unlike other methods, our bipolar readout model is general and does not make simplifying assumptions about the even-odd echo phase errors. The results show that (a) our proposed bipolar MAGPI approach improves on the phase SNR gains achieved with monopolar MAGPI and (b) the phase SNR converges with the number of echoes more rapidly with bipolar MAGPI. Importantly, bipolar MAGPI enables phase imaging in severely SNR-constrained scenarios, where monopolar MAGPI is unable to find solutions. The substantial phase SNR gains achieved with our framework are used here to (a) accelerate acquisitions (full brain 0.89 mm in-plane resolution in 2 min 30 sec) and (b) enable high-contrast high-resolution phase imaging (310 µm in-plane resolution) at clinical field strengths. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Megabar pressure phases of solid hydrogen
Chen, Nancy Hueling
The behavior of solid Hsb2, Dsb2, and HD at low temperatures high pressures was investigated. The experimental data were obtained by combining high pressure diamond anvil cell apparatus with cryogenic and spectroscopic techniques. Megabar pressures (1 bar = 10sp5 Pa) and liquid helium temperatures were accessible. The observed phases and phase lines are discussed with respect to orientational order, crystal structure, and electronic properties. The orientational order-disorder phase transition in HD was studied by Raman spectroscopy. Due to the distinguishability of the nuclei in an HD molecule, the observed phase line exhibits surprising behavior relative to that expected for the homonuclear molecules Hsb2 and Dsb2. The megabar pressure phase diagram of solid Dsb2 was investigated by infrared and Raman spectroscopy. The broken symmetry phase (BSP) transition line and the D-A phase line were observed to meet at a triple point. The relative arrangement of phase lines in P-T space, combined with group theoretical analysis of observed infrared and Raman spectra within the phases, sets symmetry restrictions on the allowed crystal structures. The electronic properties of the high pressure H-A and D-A phases were examined, since these recently discovered phases were suspected of being metallic. Acquired broadband infrared absorption spectra extending to 10 mum were analyzed in terms of the Drude model for metals. No evidence indicating metallic behavior was found. Refinements in high pressure techniques were explored, in order to increase the maximum pressures attainable. A method of extending ruby fluorescence pressure measurements to multimegabar pressures was developed, which involved excitation of ruby fluorescence with red, rather than blue or green laser light.
Size effect for phase stability on Au–Cd–Ag of phase boundary composition
Energy Technology Data Exchange (ETDEWEB)
Matsuoka, Yuki, E-mail: matsuoka@cc.nara-wu.ac.jp [Department of Physics, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Graduated School of Engineering, Osaka University (Japan); Suzuki, Keiko; Kudo, Natsuko [Department of Physics, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Graduated School of Engineering, Osaka University (Japan)
2013-11-15
Highlights: ► Size and heat treatment effects of phase boundary composition Au{sub 52.5−x}Cd{sub 47.5}Ag{sub x} were studied. ► The transformation temperature T{sub 0} increases by quench. It is investigated that disordering of atoms and lattice defects make β-phase unstable. ► Downsizing sample decreased T{sub 0} in β-phase, showed a tendency of increase in coexistent phase. ► Downsizing is supposed to make difficult nucleation for martensitic transformation. ► Increasing of surface ratio by downsizing of powder sample is estimated to make easy to transform from unstable β-phase to martensite phase. -- Abstract: Size and heat treatment effects on martensitic transformation of phase boundary composition Au{sub 52.5−x}Cd{sub 47.5}Ag{sub x} were studied. Au{sub 52.5−x}Cd{sub 47.5}Ag{sub x} has coexistent phase of β-phase and α-phase of fcc structure at x > 42 at.%. The transformation temperature T{sub 0} decreases as Au is substituted on Ag over phase boundary. T{sub 0} increases by quench in both case of bulk and powder. This behavior is investigated that disordering of atoms and lattice defects make β-phase (L2{sub 1}, B2 or bcc) unstable. Size effect was also inspected. Downsizing sample decreased the transformation temperature in β-phase. On the contrary, the transformation temperature of the coexistent phase showed a tendency of increase. Downsizing is supposed to make difficult nucleation for martensitic transformation because of reduction of β-phase ordered volume. Increasing of surface (disorder structure) ratio by downsizing of powder sample is estimated to make easy to transform from unstable β-phase to martensite phase.
Energy Technology Data Exchange (ETDEWEB)
Xue Fei [Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); Wang Zhaoxi, E-mail: wangzx03@mails.tsinghua.edu.cn [Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); Applied Mechanics Laboratory, Tsinghua University, Beijing 100084 (China); Zhang Guodong [Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); School of Mechanical and Power Engineering, Nanjing University of Technology, Nanjing 210009 (China); Qu Baoping; Shi Huiji [Applied Mechanics Laboratory, Tsinghua University, Beijing 100084 (China); Shu Guogang [Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); Liu Wei [Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)
2011-07-15
Highlights: > Thermal aging causes the Cr-rich phase precipitate and form clusters. > Phase field dynamic model is used for simulating the phase separation coarsening. > Damage initiated more easily in the ferrite matrix for the Cr clusters. - Abstract: Experiments and numerical simulations with Phase Field Model and Finite Element Analysis were carried out to investigate the phase separation dynamic properties and the corresponding thermal aging degradation mechanism. Experimental results from transmission electron microscopy and atomic force microscopy show that thermal aging causes the Cr-rich phase precipitate and form clusters. A phase field dynamic model was developed with constitutive relations and empirical potential functions to investigate the phase separation dynamics in the ferrite phase. Numerical results integrated with cell dynamical system method show clearly the micro structure morphology and the phase separation coarsening with aging time. The evolution process of the phase separation was quantitatively illustrated and reproduced macroscopically. The scattering pattern becomes clearer and the corresponding radius becomes smaller along with the increasing aging time. The average characteristic length increases firstly then decreases and enters a more stable stage. With the increment of the local Cr concentration, the evolution of the phase morphology was quite different. Finite Element Analysis simulation results with the Gurson-Tvergaard-Needleman void model show that the damage initiated more easily in the ferrite matrix for the Cr atoms forming clusters with increasing aging time. The phenomenological simulations with Phase Field Model and Finite Element Analysis were in remarkably good agreement with experimental results and analytical considerations.
Quantitative isothermal phase-field simulations of peritectic phase transformation in FeMn system
Directory of Open Access Journals (Sweden)
Celso Luiz Moraes Alves
2016-01-01
Full Text Available The present investigation shows quantitative results for the peritectic phase transformation of FeMn alloys utilizing phase-field simulations in 1-D and 2-D. The phase-field method used was based on an adaptation of the proposal of Folch and Plapp [Phys. Rev. E, 2005, 72, 011602] for the eutectic reaction. The two stages of peritectic phase transformation, the peritectic reaction and the peritectic transformation, were investigated numerically utilizing this phase-field approach. The evolution of the phases was quantitatively analyzed during the peritectic transformation and the fractions of the phases at the end of the solidification were compared with the thermodynamic equilibrium, defined by the phase diagram, for the case of 1-D simulation with peritectic concentration. An assessment of the behavior of the concentration gradient in the γ-phase (the peritectic phase through time was also carried out and a mathematical function which describes the γ-phase thickness evolution was defined. Finally, 2-D simulations were performed to clearly identify the two stages of the peritectic phase transformation. The obtained results show two main facts: (1 the numerical model is able to simulate quantitatively this phase transformation; and, (2 this numerical tool can be utilized for investigating quantitatively some aspects (normally determined indirectly that are difficult to be determined by direct measurements in experimental works.
Evolutions of Yang Phase Under Cyclic Condition and Adiabatic Condition
Institute of Scientific and Technical Information of China (English)
QIAN Shang-Wu; GU Zhi-Yu
2005-01-01
There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the generaltime-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases.
Modeling the phase diagram of carbon
Ghiringhelli, L.M.; Los, J.H.; Meijer, E.J.; Fasolino, A.; Frenkel, D.
2005-01-01
We determined the phase diagram involving diamond, graphite, and liquid carbon using a recently developed semiempirical potential. Using accurate free-energy calculations, we computed the solid-solid and solid-liquid phase boundaries for pressures and temperatures up to 400 GPa and 12 000 K, respect
Binary Solid-Liquid Phase Equilibria
Ellison, Herbert R.
1978-01-01
Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)
Phase Equilibria of Stored Chemical Energy Reactants.
1984-07-25
The reaction of lithium aluminum alloy with water at high temperature is considered in terms of phase equilibria in the system Li-A1-0-H. A...thermodynamic analysis of the system reveals the potential importance of lithium hydride as a reaction product. Major needs for experimental phase equilibria data
Riemann Zeros and the Inverse Phase Problem
Tourigny, David S.
2013-10-01
Finding a universal method of crystal structure solution and proving the Riemann hypothesis are two outstanding challenges in apparently unrelated fields. For centro-symmetric crystals however, a connection arises as the result of a statistical approach to the inverse phase problem. It is shown that parameters of the phase distribution are related to the non-trivial Riemann zeros by a Mellin transform.
Fractional topological phase for entangled qudits
Oxman, L E
2010-01-01
We investigate the topological structure of entangled qudits under unitary local operations. Different sectors are identified in the evolution, and their geometrical and topological aspects are analyzed. The geometric phase is explicitly calculated in terms of the concurrence. As a main result, we predict a fractional topological phase for cyclic evolutions in the multiply connected space of maximally entangled states.
ATLAS Phase-II trigger upgrade
Sankey, Dave; The ATLAS collaboration
2016-01-01
This talk for ACES summarises the current status of the ATLAS Phase-II trigger upgrade, describing and comparing the two architectures under consideration, namely the two hardware level system described in the Phase-II Upgrade Scoping Document and the more recent single hardware level system.
Phase Coherence Zones in Flight Simulation
Jonik, P.M.; Valente Pais, A.R.; Van Paassen, M.M.; Mulder, M.
2011-01-01
In flight simulation detailed knowledge of human motion perception is crucial. Phase differences between inertial and visual motion introduced by motion filters might have negative effects on the fidelity of flight simulation. This study investigated human visual- vestibular phase-error detection. A
Field induced phase segregation in ferrofluids
Kooij, Ernst S.; Galca, A.C.; Poelsema, Bene
2008-01-01
We study the phase segregation in magnetite ferrofluids under the influence of an external magnetic field. A phase with lower nanoparticle density and corresponding higher optical transmission is formed in the bottom of a glass cell in the presence of only a very modest magnetic field gradient (smal
Phase transitions in the web of science
Phillips, J. C.
2015-06-01
The Internet age is changing the structure of science, and affecting interdisciplinary interactions. Publication profiles connecting mathematics with molecular biology and condensed matter physics over the last 40 years exhibit common phase transitions indicative of the critical role played by specific interdisciplinary interactions. The strengths of the phase transitions quantify the importance of interdisciplinary interactions.
Quantum Phase Transitions in a Finite System
Leviatan, A
2006-01-01
A general procedure for studying finite-N effects in quantum phase transitions of finite systems is presented and applied to the critical-point dynamics of nuclei undergoing a shape-phase transition of second-order (continuous), and of first-order with an arbitrary barrier.
The Berry Phase for Simple Harmonic Oscillators
Suslov, Sergei K
2011-01-01
We evaluate the Berry phase for a "missing" family of the square integrable wavefunctions for the linear harmonic oscillator, which cannot be derived by the separation of variables. It is obtained by the action of the maximal kinematical invariance group on the standard solutions. An explicit simple formula for the phase is found by integration with the help of a computer algebra system.
RIEMANN ZEROS AND THE INVERSE PHASE PROBLEM
TOURIGNY, DAVID S.
2013-01-01
Finding a universal method of crystal structure solution and proving the Riemann hypothesis are two outstanding challenges in apparently unrelated fields. For centrosymmetric crystals however, a connection arises as the result of a statistical approach to the inverse phase problem. It is shown that parameters of the phase distribution are related to the non-trivial Riemann zeros by a Mellin transform. PMID:24293780
Second Order Mode Selective Phase-Matching
DEFF Research Database (Denmark)
Lassen, Mikael Østergaard; Delaubert, Vincent; Bachor, Hans. A-
2006-01-01
We exploit second order (χ(2)) nonlinear optical phase matching for the selection of individual high order transverse modes. The ratio between the generated components can be adjusted continuously via changes in the phase-matching condition. ©2007 Optical Society of America...
The Moon's Phases and the Self Shadow
Young, Timothy; Guy, Mark
2008-01-01
In this article, the authors present a new way of teaching the phases of the Moon. Through the introduction of a "self shadow" (an idea of a shadow that is not well-known), they illuminate students' understanding of the phases of the Moon and help them understand the distinction between the shadows that cause eclipses and the shadows that relate…
The Organizational Phase of Project Open Book.
Waters, Donald; Weaver, Shari
The Yale University Library is now organized to move ahead with Project Open Book, the conversion of 10,000 books from microfilm to digital imagery. In the first phase of the Project--the organizational phase--a Steering Committee was established that included several faculty members, and a project team was created. In addition, Yale conducted a…
Ferroelectric phase diagram of PVDF:PMMA
Li, M.; Stingelin, N.; Michels, J.J.; Spijkman, M.-J.; Asadi, K.; Feldman, K.; Blom, P.W.M.; Leeuw, D.M. de
2012-01-01
We have investigated the ferroelectric phase diagram of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA). The binary nonequilibrium temperature composition diagram was determined and melting of α- and β-phase PVDF was identified. Ferroelectric β-PVDF:PMMA blend films were made b
Ferroelectric Phase Diagram of PVDF : PMMA
Li, Mengyuan; Stingelin, Natalie; Michels, Jasper J.; Spijkman, Mark-Jan; Asadi, Kamal; Feldman, Kirill; Blom, Paul W. M.; de Leeuw, Dago M.
2012-01-01
We have investigated the ferroelectric phase diagram of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA). The binary nonequilibrium temperature composition diagram was determined and melting of alpha- and beta-phase PVDF was identified. Ferroelectric beta-PVDF:PMMA blend films w
Lidar to lidar calibration phase 2
DEFF Research Database (Denmark)
Yordanova, Ginka; Courtney, Michael
This report presents the results from phase 2 of a lidar to lidar (L2L) calibration procedure. Phase two of the project included two measurement campaigns conducted at given sites. The purpose was to find out if the lidar-to-lidar calibration procedure can be conducted with similar results...
Non-rotator phases in phospholipid monolayers?
DEFF Research Database (Denmark)
Kenn, R.M.; Kjær, K.; Möhwald, H.
1996-01-01
Monolayers of diacylphosphatidylethanolamines at the air/water interface are studied by grazing incidence X-ray diffraction. The results prove the existence of phases which show analogies with the rotator phases of single-chain surfactants: hexagonal tail lattice with no tilt; rectangular lattice...
Pang, X.; Gbur, G.; Visser, T.D.
2011-01-01
The phase behavior of Airy beams is studied, and their Gouy phase is defined. Analytic expressions for the idealized, infinite-energy type beam are derived. They are shown to be excellent approximations for finite-energy beams generated under typical experimental conditions.
The Structural Phase Transition in Solid DCN
DEFF Research Database (Denmark)
Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.
1975-01-01
Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies...... and showed 'softening' as the transition temperature was approached from above....
Phase-Modulation Laser Interference Microscopy
DEFF Research Database (Denmark)
Brazhe, Alexey; Brazhe, Nadezda; Maximov, G. V.
2008-01-01
We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various...
Phase contrast imaging of Bose condensed clouds
Meppelink, R; Rozendaal, R.A.; Koller, S.B.; Vogels, J.M.; van der Straten, P.
2010-01-01
Phase contrast imaging is used to observe Bose-Einstein condensates (BECs) at finite temperature in situ. The imaging technique is used to accurately derive the absolute phase shift of a probe laser beam due to both the condensate and the thermal cloud. The accuracy of the method is enhanced by usin
Complex phase dynamics in coupled bursters
DEFF Research Database (Denmark)
Postnov, D E; Sosnovtseva, Olga; Malova, S Y
2003-01-01
The phenomenon of phase multistability in the synchronization of two coupled oscillatory systems typically arises when the systems individually display complex wave forms associated, for instance, with the presence of subharmonic components. Alternatively, phase multistability can be caused...... the number of spikes per train and the proximity of a neighboring equilibrium point can influence the formation of coexisting regimes....
VSOP-2 Astrometric Accuracy with Phase Referencing
Asaki, Y.; Kono, Y.
2009-08-01
The VSOP-2 mission is expected to conduct phase referencing observations with the unprecedented spatial resolutions at 8.4, 22, and 43 GHz together with the ASTRO-G satellite. In this report, VSOP-2 astrometry with phase referencing is examined in detail based on a simulation tool, ARIS.
Phase diagram distortion from traffic parameter averaging.
Stipdonk, H. Toorenburg, J. van & Postema, M.
2010-01-01
Motorway traffic congestion is a major bottleneck for economic growth. Therefore, research of traffic behaviour is carried out in many countries. Although well describing the undersaturated free flow phase as an almost straight line in a (k,q)-phase diagram, congested traffic observations and