Bonn-Gatchina partial wave analysis

The present status of the Bonn-Gatchina partial wave analysis of the photoproduction and pion induced data is presented. An observation of signals which can be associated with new baryon resonances and possible interpretations of the baryon spectrum is discussed.     

Pseudo bearing sequence analysis

1 IntroductionOne thing can not be differentiated from another if there is no difference between them.Signal detection is intended to differentiate whether only noise or the signal is in fact presentin the received sequence. Either of the two hypotheses must be declared, which is called dualchoice detection. In ideal conditions, the optimum detector for a determined signal is a matchedfilter or a replica correlator in terms of both the maximum out put' st anal t o- no ise r at ic crit erionand…     

Dynamic dislocation–defect analysis

The dynamic internal variables which control plastic flow can only be assessed by dynamic materials testing at any given instance. The testing method championned by our studies has been precision strain rate sensitivity (PSRS) whereby the change in flow stress due to a set change in strain rate is taken to be an operational measure of the activation volume and its product with the flow stress gives rise to the operational activation work. Also, from the work hardening slope, a modelled parameter proportional to the mean slip distance (λ) is simultaneously determined. The deviation from the linear Cottrell–Stokes relation as determined with the Haasen plot indicates the evolution of secondary defects other than monopole dislocations. Hence PSRS can assess the theoretical predictions of the activation distance (d) and work as a function of temperature, resulting in quantitative values that are in accord with dislocation theory at temperatures below that where point defects become mobile. A method to calibrate λ using Stage II slope θ_II shows that λ/?, where ? is the mean forest dislocation spacing, is inversely proportional to θ, the work hardening coefficient. This analysis has led to a new plot of θ_II/θ versus b ²λ/ν where b is the Burgers vector and its slope is directly proportional to d. An example using an alumina-dispersed high conductivity copper shows that geometrically necessary punched out loops are continuously generated. The role of point defect mobility is dramatically illustrated by load drops in [001] aluminium crystals with the formation of slip clusters.     

Roy equation analysis of ππ scattering

We analyse the Roy equations for the lowest partial waves of elastic ππ scattering. In the first part of the paper, we review the mathematical properties of these equations as well as their phenomenological applications. In particular, the experimental situation concerning the contributions from intermediate energies and the evaluation of the driving terms are discussed in detail. We then demonstrate that the two S-wave scattering lengths a₀⁰ and a₀² are the essential parameters in the low energy region: Once these are known, the available experimental information determines the behaviour near threshold to within remarkably small uncertainties. An explicit numerical representation for the energy dependence of the S- and P-waves is given and it is shown that the threshold parameters of the D- and F-waves are also fixed very sharply in terms of a₀⁰ and a²₀. In agreement with earlier work, which is reviewed in some detail, we find that the Roy equations admit physically acceptable solutions only within a band of the (a₀⁰,a₀²) plane. We show that the data on the reactions e⁺e⁻→ππ and τ→ππν reduce the width of this band quite significantly. Furthermore, we discuss the relevance of the decay K→ππeν in restricting the allowed range of a₀⁰, preparing the grounds for an analysis of the forthcoming precision data on this decay and on pionic atoms. We expect these to reduce the uncertainties in the two basic low energy parameters very substantially, so that a meaningful test of the chiral perturbation theory predictions will become possible.     

Mode analysis of axially-asymmetric optical resonators

The characteristics of an axially-asymmetric optical resonator(AAOR)areanalysed by using the variable reference plane method.The positions of the beam waist andthe plane wavefront are obtained.The variation of the beam size ellipse and wavefront curva-ture ellipse are also discussed.     

Wavelet analysis of helicopter noise signal

1 IlltroductionAt the preseni tAne, for civil helicopters, stronger lindation is Anposed by certilicationrules to reduce acoustic nulsance. And for nillltary helicopters, noise reduction has aIso beenconcerned in liIIiltation of detectability. Therefore hellcopter noise generation and conirol hasbecome an increasingly important problem for the helicopter design. Por turbine-driven hell-copter widely used at presellt, the noise generation mechaIilsm can be divided into aerodynandcnoise and m…     

Phase-space analysis of alternating Δβ couplers

A geometrical method for determining the power transfer between piecewise uniform, alternating , twin-core linear directional couplers is presented. Phase space provides the basis for the method.     

Quantum analysis on the four-photon interference

We present a theory for quantum interference of four photons generated by spontaneous parametric downconversion. Detailed investigation of the dependence of fourfold coincidence count rate on time delay between the incident and the reflective pump laser pulses is carried out. Gaussian type dependence is found, and good agreement between our theoretical results and experimental data reported in the literature is achieved.     

Theoretical analysis of acoustic suspended sediment observation

1 IntroductionSince 1980 s the obserVations of suspended sedimellts based on acoustical back-scatteringhave been applied to the studies of sediment dynamics in the estuary and coastal area and tothe monitoring of the marine pollutant and plankton[1--lol. Compared with the clajssical watersampling and the optical obserwtions, the acoustical ObserVation can continuously observe thein-site sediment concentration profilers along the water depth and their variation with timewithout disturbing the …     

Intrinsic stress analysis of sputtered carbon film

Intrinsic stresses of carbon films deposited by direct current (DC) magnetron sputtering were investigated. The bombardments of energetic particles during the growth of films were considered to be the main reason for compressive intrinsic stresses.The values of intrinsic stresses were determined by measuring the radius of curvature of substrates before and after film deposition.By varying argon pressure and target-substrate distance,energies of neutral carbon atoms impinging on the growing films were optimized to control the intrinsic stresses level.The stress evolution in carbon films as a function of film thickness was investigated and a void-related stress relief mechanism was proposed to interpret this evolution.     

Numerical analysis of multicore photonic crystal fibers

A Galerkin's method-based numerical procedure is extended to obtain the modal field distribution of multicore photonic crystal fibers for the first time to our knowledge, which can reveal how the air hole size influences the mode coupling and how the coupling strength varies with wavelength. These results will be helpful in the future design of multicore photonic crystal fibers with proper guidance properties.     

Statistical energy analysis of similarly coupled systems

1 IntroductionStatistical Energy Analysis (SEA)I'] is a powerful method fOr dealing with dynamic prolylems of a complex structu-ral or acoustical system. The development of SEA for non--con-ser\u-tively coupled systems1'], as well as SEA of coupled systems under correlative excitationsI3],makes the method more appllcable and practical in the analysis and control of structuralnoise/vibration. In a corn-mon sense, the consertutive coup1ing and the non--consertutive oneare the only two coup…     

Scheme-scale ambiguity in analysis of QCD observable

The scheme-scale ambiguity that has plagued perturbative analysis in QCD remains on obstacle to making precise tests of the theory.Many attempts have been done to resolve the scale ambiguity.In this regard the BLM,EC,PMS and CORGI approaches are more distinct.We try to employ these methods to fix the scale ambiguity at NLO,NNLO and even in more higher order approximations.By optimizing the renormalization scale,there will be a possibility to predicate higher order terms.We present general results for predicted terms at any order,using different optimization methods.Some observable as specific examples will be used to indicate the validity of scale fixing to predicate the higher order terms.     

A fuzzy-clustering analysis based phonetic tied-mixture HMM

To efficiently decrease the size of parameters and improve the robustness of parameters training, a fuzzy clustering based phonetic tied-mixture model, FPTM, is presented. The Gaussian codebook of FPTM is synthesized from Gaussian components belonging to the same root node in phonetic decision tree. Fuzzy clustering method is further used for FPTM covariance sharing. Experimental results show that compared with the conventional PTM with approximately the same parameters size, FPTM decrease the size of Gaussian weights by 77.59% and increases word accuracy by 7.92%, which proves Gaussian fuzzy clustering is efficient. Compared with FPTM, covariance-shared FPTM decreases word error rate by 1.14% , which proves the combined fuzzy clustering for both Gaussian and covariance is superior to Gaussian fuzzy clustering alone.     

Output beam analysis of high power COIL

As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instability appears as the far-field beam spot drift and deformation for the large Presnel number unstable resonator. In order to interpret this phenomenon, an output beam mode simulation code was developed with the fast Fourier transform method. The calculation results show that the presence of the nonuniform gain in COIL produces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermal expansion. With the output power of COIL increases, the mirror surfaces, especially the back surface of the scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beam spot seriously. The initial misalignment direction is an important factor for the far field beam spot drifting and deformation.     

Methods for bearings-only underwater target motion analysis

I.IlltroductionBearings-onlyunderwatertargetmotionanalysisaimsattheestimationoftargetmotionparametersviabearingobservationsonlyItisassumedherethatthestatisticalcharacteristicsoferrorsoftargetbearingsobservedbydetectorisdetermined.Targetmotionanalysisconsistsoftheestimationofinitialdistanceandbearingbetweentargetandownship,targetcourseandvelocityItneedsmorememoryspaceandprocessingtimeusingbatchprocessingmethod,andfurthermoreunsuitableforrealtimeestimation.Sequentialestimationmethodontheotherha…     

Ring microfiber coupler erbium-doped fiber laser analysis

A non-adiabatic microfiber coupler is fabricated by flame brushing technique and then theoretically and experimentally analyzed.The effective length of the microfiber coupler is determined by simulation,and a low-noise laser is demonstrated using various lengths of erbium-doped fiber(EDF) when incorporated in a laser setup.At 18.6-mW input pump power,the maximum output power of 20 μW and the lowest lasing threshold of 3.8 mW are obtained with a 90-cm-long EDF.     

Dynamic analysis of optical fluid in medium

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Acoustic signal analysis of underwater elastic cylinder

1 IntroductionThe characteristics of underwater elastic cylinder comprise two types of acoustic compo-nents. One is elastic scattering highlights, or resonat scattering highlights related with theelasticity of the cylinder, and the other is geometric scattering highlights, or namely mirroredwave and corner waves due to the target shape. The natuxal resonating frequencies appearas modulations on the frequency domain of target echoes. The resonant scattering highlightsdiffer from its incident wa…     

Theoretical analysis of BLM system for HLS Ⅱ

Hefei Light Source (HLS) is being upgraded to HLS Ⅱ. Its emittance will be much lower than before, therefore the Touschek scattering will increase significantly and become the dominant factor of beam loss. So it is necessary to build a new beam loss monitoring (BLM) system that, in contrast to the old one, is able to obtain the quantity and position information of lost electrons. This information is useful in the commissioning, troubleshooting, and beam lifetime studying for HLS Ⅱ. This paper analyzes the distribution features of different kinds of lost electrons, introduces the operation parameters of the new machine and discusses how to choose proper monitoring positions. Based on these comprehensive analyses, a new BLM system for HLS Ⅱ is proposed.