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Neutron total cross section measurements of {sup 122}Sn has been analyzed over the energy range 0.013 to 0.310 MeV. The R - matrix analysis has resulted in resonance and average parameters which provide for a complete representation of the neutron entrance the s{sub 1/2}, p{sub 1/2}, and p{sub 3/2} contributions. The s - and p - neutron strength functions have been determined to be 0.123 {plus_minus} 0.023 and 2.0 {plus_minus} 0.200, respectively (in units of 10{sup {minus}4}). Limits are placed on level spacings and strength functions for the individual partial wave components. The s - wave potential scattering radius has been determined to be 6.3 {plus_minus} 0.1 fm. Average scattering functions, deduced from the average parameters, have been used to determine the real well depth of an optical model potential which reproduces these functions. We find, as have others, that the real well depth is parity dependent. Two computer codes were developed: (1) a minimization program for finding parameters of a dispersive optical model which reproduce the high resolution data of the ORELA facility, and (2) an X-windows graphical user interface has been developed to permit interactive resonance analysis of the neutron total cross section data using analysis-and-minimization codes developed previously. These will contribute to the more routine analysis of ORELA data.

[8-13C-7-15N]-labelled theophylline was synthesized and applied for in situ analysis using a 1H–{13C–15N} triple resonance NMR technique. The triple resonance analysis enabled selective detection of labelled theophylline in a mixture containing excess amino acids or crude mouse liver extract, where conventional 1H NMR analysis suffers from difficulty because of background signals.

Comparison has been made between the empirical integrated strengths and external R-functions and the predictions of a dispersive optical model for the n-{sup 208}Pb system, for partial waves through f{sub 7/2}. Parameters of a constant geometry model give a fair representation of the experimental results. A hint of the need for a parity dependence in one of the model parameters is seen in the two data and in thetotal cross section in the low-energy region. Other research performed consisted of: (1) refinement of the resonance analysis of the n-{sup 208}Pb system, resulting in more definitive J{sup {pi}} assignments and external R-functions consistent over the neutron energy range [80--1760 keV]; (2) background correction and processing of n-{sup 88}Sr differential scattering cross section data for use with total cross section data for R-matrix analysis (3) measurement of the n-{sup 90}Zr differential scattering cross section at the 200-m flight path of the ORELA.

Large discrepancies exist between the high-resolution 59Co neutron transmission data of Harvey et al. and the resolved resonance parameters of ENDF/B-VI. In order to provide new resonance parameters consistent with these data, the high-resolution transmission measurements have been analyzed with the computer code SAMMY. Results of that analysis are reported here.

Large discrepancies exist between the high-resolution {sup 59}Co neutron transmission data to Harvey et al. and the resolved resonance parameters of ENDF/B-VI. In order to provide new resonance parameters consistent with these data, the high-resolution transmission measurements have been analyzed with the computer code SAMMY. Results of that analysis are reported here.

An ultrasound probe (101) is placed on the head of a patient, and is used to generate an ultrasound pulse which propagates through the skull and brain of the patient, and is reflected off of the skull and soft tissue lying in a path perpendicular to the ultrasound probe (101). The reflected signals are received by the ultrasound probe, and then processed in a known manner to generate an echo encephalogram (Echo EG) signal, which is plotted as a function of amplitude vs. distance. A portion of the Echo EG signal is then selected, and the Echo EG signal is integrated over the selected portion to generate an echo pulsograph (EPG) signal. An electrocardiograph (ECG) signal for the patient is also generated in a known manner. Using the ECG signal as a reference, the EPG signal is used to provide information regarding the physiological state of the tissue at a depth from the ultrasound probe (101) corresponding to the selected portion of the Echo EG signal. In addition, the ultrasound probe is preferably a probe having a concave shaped transmitting and receiving surface.

Inverse scattering of fluid‐loaded, elastic, thin‐walled cylindrical shells is addressed by multiple‐aspect resonance analysis. A set of aspect‐dependent acoustic phenomena is selected from membrane wave and resonance scattering theories, which are expected to be backscattered by fluid‐filled or empty thin‐walled shells and to give rise to resonance phenomena in the ka range (1,50). The features selected are from spatial axial modes, and Lamb‐type, Scholte–Stoneley, and shear helical waves. The last three wave families are significant only over a small range of target aspects near broadside, with the width of this range depending on shell properties. Approximate equations are formulated relating resonance behavior in the aspect‐frequency domain, to target parameters such as shell outer radius, thickness, length, and material. The inverse methodology is validated on experimental data from a steel cylindrical shell with flat end‐caps, filled with air or water and suspended in the water column. The target wa...

Cross sections and angular distributions for the 26 Mg(p, n) 26 Al and 23 Na(α, n) 26 Al reactions, populating the ground state and the first three excited states in 26 Al, have been measured between 5.3 and 7.0 MeV proton bombarding energy and between 3.9 and 5.9 MeV alpha bombarding energy, using the neutron time-of-flight technique. The measured total cross sections were used to derive the cross sections for the astrophysically interesting reactions 26 Al(n, p 0 ) 26 Mg and 26 Al(n, α 0 ) 23 Na. The 26 Mg(p, p′) 26 Mg and 26 Mg(p, α) 23 Na cross sections were also measured at E p = 5.3–6.1 MeV. A resonance analysis of the measured 26 Mg+p excitation functions is used to obtain information on cross sections for the 26 Al(n, p') 26 Mg reaction.

The excitation functions of the elastic scattering 12C(p, p)12C and the reactions 12C(p, p′)12C (4.44 MeV) and 12C(p, α)9Bg.s. have been measured at θ = 175° in the region of the first T = 3 2 state in 13N with high energy resolution. A straightforward resonance analysis of the elastic scattering data yields Γ = 1.10 ± 0.09 keV, Γp = 210 ± 11 eV and Γ p Γ = 0.191 ± 0.017 . The results are compared with shell-model predictions. The additionally measured angular distributions of the elastic scattering 12C(p, p)12C above and below the resonance are compared with optical model calculations. The combination of the present results for Γp and Γp/Γ with previous results for Γγ/Γp and ΓγΓp/Γ yields Γγ = 27.0 ± 2.2 eV as a new determination of the 13 N (T = 3 2 , 15.07 MeV → T = 1 2 , 0 MeV ) γ-decay width. The comparison with the analogous γ-decay in 13C is discussed with respect to the charge symmetry of corresponding ΔT = 1 γ-transitions in mirror nuclei.

An 18.1-\ensuremath{\mu}g sample of $^{237}\mathrm{U}$ (half-life 6.70 \ifmmode\pm\else\textpm\fi{} 0.02 day) was prepared and exposed to a neutron beam from the underground nuclear explosion Pommard. The neutron-induced fission cross section was measured from 43 to 1000 eV and from 0.1 to 2 MeV. A resonance analysis was attempted from 43 to 220 eV; resonance areas are reported. Both ${0}^{+}$ and ${1}^{+}$ seem to be present, with average spacing 3.5 eV. The cross section at 1 MeV is 1.0 \ifmmode\pm\else\textpm\fi{} 0.1 b; from 300-1000 eV, the cross section is 30% of that for $^{239}\mathrm{Pu}$.[NUCLEAR REACTIONS, FISSION $^{237}\mathrm{U}(n,f)$, $E=43\ensuremath{-}1000$ eV, $E=0.1\ensuremath{-}2$ MeV; measured $\ensuremath{\sigma}(E)$. Nuclear explosion.]

The photoionisation cross section for the ground state 2s22p4 3P of O I is calculated in the close-coupling approximation employing the frozen-cores model. Results include detailed resonance analysis using accurate interpolation and extrapolation procedures. Similar calculations by Taylor and Burke (1976) and recent experimental data of Kohl et al. (1978) are in good agreement with present results.

The /sup 241/Pu total cross-section measurement of others and the neutron fission cross-section measurements were analyzed with the R-matrix resonance analysis program SAMMY, which uses Bayes' equation to extract resonance parameters from the experimental data. A set of Reich-Moore-type resonance parameters that describes the cross sections up to 100 eV was obtained. It is shown that existing data are not adequate for a precise evaluation of the resonance cross sections, and the need for additional work is discussed.

The present paper is concerned with the nonlinear finite solution of the postbuckling instability behaviour of thin shell structures in resonance regions of vibration. The development of reliable and efficient techniques for handling the dynamic postbuckling behaviour is emphasized. An illustrative solution associated with the postbuckling resonance response of thin shells is presented.

A resonance analysis was performed of the26Al(n, p0)26Mg(g.s.) and Al(n, α0)23Na(g.s.) reactions atEn=(0÷150) keV. The extracted resonance parameters were used to make predictions about the destruction rate of26Al via the26Al(n, p)26Mg and26Al(n, α)23Na reactions, at stellar temperaturesT=(108÷109)K.

Angular distributions of cross section and analyzing power for elastic scattering of protons from 15N have been measured for Ep = 2.7–7.0 MeV. A phase-shift analysis of the data yields spin-parity assignments and level parameters for seventeen states of 16O in the excitation energy region 14.8–18.6MeV. Three of the resonances have not previously been identified, among them being a broad Jπ = 2− level at Ep = 6.1 MeV which is almost certainly the analog of the 2− 1p1h state with configuration ( d 3 2 , p 1 2 −1 ) at Ex ∽ 5.0 MeV in 16N. The broad level previously reported near Ep = 5.0 MeV has been observed and its parameters determined. A resonance analysis of the phase shifts yielded values of Er, Γ and Γp for all of the levels. The Jπ assignments are in agreement with previously reported values. For resonances having J = l, the data can usually be fit with a resonant phase shift corresponding to either J = l + 1 or J = l − 1, in addition to the phase shift for J = l. Which of the two spurious-J solutions occurs seems to depend on whether the partial wave through which the resonant state is formed is J = l + 1 2 or J = l − 1 2 .

The neutron total and capture cross sections of92,94Zr have been measured at the 80 and 40 m flight stations, respectively, on the Oak Ridge Electron Linear Accelerator (ORELA). Resonance analysis of the total cross sections gave values of s, p 3 2 and p 1 2 strength functions. Strong intermediate structure was observed in the p 3 2 cross section of 92Zr. Significant single particle transitions identified in the p-wave capture cross section indicate the importance of the valence process for both nuclei. It is noted that the intermediate structure in the p 3 2 total cross section leads to enhanced valence effects in the capture cross section. The effects of non statistical E1 transitions following particle-hole annihilation in the compound states were not observed in either the 92Zr or 94Zr capture cross sections as they had been in that for 90Zr.

Neutron transmissions through 0.076-, 0.254-, 1.080-, and 3.620-cm-thick samples of isotopically enriched 238U have been measured from 0.88 to 100.0 keV using a time-of-flight technique over a path...

Elastic 16 O 28 Si scattering is studied microscopically within the Generator Coordinate Method. A resonance analysis supplies a series of three rotational bands; the two excited bands agree very well with rotator-like structures found in experiment. The phase shifts do not show any parity dependence.

We have constructed a model of the Q enhancement in Kππ spectra in which the Q is regarded as dominated by diffractive production of two 1+ mesons. We show that our model accounts satisfactorily for the Kππ mass spectrum in the Q region and for the relative amounts of ϱK and K∗π as a function of mass. Regarding the A1 phenomenon as a diffractively produced meson, we find our derived parameters yield values of the A1 and B widths in accord with experiment, and study their implications for the A1 nonet. We also make predictions concerning Q production through strangeness and charge exchange.

A classification of ODE from the point of view of singular point analysis is suggested. The general formula for the Painleve resonances is derived and the resonance analysis of low-order dominant truncations is performed. The resonance formulae for the Painleve chains are presented and the significance of the Painleve chains for the classification is explained.

The 33S(n, α ) cross section has been measured for neutron energies up to 1 MeV. The neutron flux has been determined by the 6Li(n, α) and 235U(n, f) reactions. A resonance analysis has been performed up to 400 keV neutron energy which yields α-widths Γα or values of gΓnΓα/Γ for 16 resolved resonances. Average resonance parameters are discussed and the maxwellian averaged (n, α) cross section is obtained for the temperature range from 10 to 200 keV.

We determinedN* electromagnetic transition form factors using π- and η-electroproduction data in the resonance region published till December, 1978. We discuss problems with the results obtained by various experimental groups. The method of analysis is a modification of the procedure used by Devenish and Lyth. Using the new photoproduction results of Barbour and Crawford and the δ- and η-data published till 1978, we are able to parametrise all multipoles in a unique way and to describe the background without further high energy input. Thus a better description of the data with less assumptions is achieved. However, it is still not possible to determine more multipoles than previously.

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Integral cross sections have been measured for the two analogous reactions 6Li(n, p)6He(0) and 6Li(n, n')6Li(3.56) from the thresholds up to about 7 MeV with an energy resolution between 50 and 200 keV. The excitation functions exhibit annomaly at En = 4.6 MemMeV which is interpreted as due to the lowest T = frcase|3/2 state in the compound nucleus 7Li. The data are well fitted by the assumption of two overlapping resonances of the same spin and parity ( 3 2 − ) . A two-level resonance analysis yielded the following level parameters: E x (1) ( 7 Li ) = 10.25±0.10 MeV , Γ (1) = 1.40±0.10 MeV , T (1) = 1 2 ; E x (2) ( 7 Li ) = 11.20±0.05 MeV , Γ (2) = 0.27±0.05 MeV , T (2) = 3 2 . Partial widths and reduced widths of the resonances were derived or estimated, and their implications for the structure and isospin purity of the resonant states are discussed.

The pre-operative evaluation of patients with vitreous opacifications has been greatly enhanced by ultrasonic examination. The location and extent of vitreous hemorrhage may now be ascertained with a high degree of confidence, but the differentiation of hemorrhage, vitreous membranes and retina is a difficult but essential distinction.

The 238Pu neutron cross-sections have been evaluated in the energy range 10−5 ev to 16 Mev. The anomalies observed in the measured total cross-sections (very high value of the potential scattering cross-section) and the measured capture cross-sections (high value of the non resonant part in the resolved and unresolved region) have been examined and considered as being due to some unknown experimental effect. More realistic cross-sections have been proposed from statistical and optical model calculations based on average parameters deduced from the resonance analysis and the experimental fission cross-sections which seem to be reasonably well known on the entire energy range.

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A recently proposed dual-resonance model for diffraction dissociation is extended to two-pion photproduction on protons and shown to give good agreement with experimental data. It yields vectormeson dominance in the sense of a strongly ρ-dominated two-pion mass spectrum and moreover explains the observed deviation of the ρ peak from a Breit-Wigner shape as well as the «background». Further experimental tests are proposed.

Elimination of chaotic behavior in the harmonically driven van der Pol oscillator by means of a comparatively weak additional forcing was studied through geometrical resonance analysis. We considered commensurate and incommensurate cases together with the effect of the phase difference between the forcings. The analysis provided parameter-space regions for regularization that were corroborated by numerical experiments, including instances with clearly large chaos-inducing forcing. A reinterpretation of a classical result, due to Cartwright and Littlewood @J. London Math. Soc. 20, 180 ~1945!#, was also derived by means of geometrical resonance analysis. @S1063-651X~97!06008-X#

The problem of experimentally determining the dynamic characteristics of resilient vibration isolation materials has been solved using two techniques. The test methods, instrumentation and the readouts in terms of impedance and transmissibility are described. Results of impedance and resonance analysis are discussed for several sample materials under different degrees of loading. The results are compared with theoretical values. Static values for materials with high hysteresis are also given in terms of standard stress‐strain curves. The differences between static and dynamic spring constants are discussed.