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1.
C.J. Batty S.F. Biagi M. Blecher R. Kunselman R.A.J. Riddle B.L. Roberts J.D. Davies G.J. Pyle G.T.A. Squier D.M. Asbury M. Leon 《Nuclear Physics A》1978,296(3):361-372
The attenuation due to the E2 nuclear resonance effect has been measured in hadronic atoms using pions with 111Cd and 112Cd, and for kaons with 122Sn. Energies of the relevant X-ray and γ-ray transitions and of the X-ray cascade intensities have also been measured so as to give a self-consistent set of information. The results are found to be in very good agreement with theoretical calculations. 相似文献
2.
A new technique to analyze aqueous samples for nanograms per liter levels of volatile and semivolatile compounds using microextraction and thermal desorption into a gas chromatograph/ion trap mass spectrometer (GC/MS) is described. This method is inherently sensitive (50 mL of aqueous sample is extracted prior to each desorption), uses no solvents, and detects volatiles and semivolatiles in the same analysis. Aqueous standards and environmental samples are pumped through a length of porous-layer open-tubular capillary column, which is then thermally desorbed onto a 30 m × 0.25 mm i.d. analytical column interfaced to an ion trap mass spectrometer for subsequent separation and detection. Sharp chromatographic peaks and reproducible retention times (RT) were observed. Replicate injections of surrogates (n = 6) averaged 32.6% R.S.D. Analysis of domestic tap water detected 55 analytes, some at the low-nanograms per liter level, and detected 3 halogenated ethenes, not previously reported in drinking water. Analysis of an aqueous sample from a municipal ground water source detected the presence of numerous semivolatile compounds at trace-levels. 相似文献
3.
Klaus H. Berkner David Leung Robert V. Pyle Alfred S. Schlachter J.Warren Stearns 《Physics letters. A》1977,64(2):217-218
Equilibrium charge-state fractions of 2.7–31 keV deuterium in strontium vapor are reported. The energy dependence of the D- equilibrium yield is discussed. The results are compared with the D- yield in cesium and magnesium vapors. 相似文献
4.
C.J. Batty S.F. Biagi M. Blecher S.D. Hoath R.A.J. Riddle B.L. Roberts J.D. Davies G.J. Pyle G.T.A. Squier D.M. Asbury A.S. Clough 《Physics letters. [Part B]》1978,76(1):44-46
The Doppler broadened 26Mg* decay gamma peak hasma peak has been observed in coincidence with stopped kaons in an Al target. The results are compared with predictions based on single-nucleon absorption of the kaon. 相似文献
5.
P.M. Bird A.S. Clough K.R. Parker G.J. Pyle G.T.A. Squier S. Baird C.J. Batty A.I. Kilvington F.M. Russell P. Sharman 《Nuclear Physics A》1983,404(3):482-494
The X-ray spectrum obtained with kaons stopping in liquid hydrogen has been measured. Possible candidates for X-ray lines from kaonic hydrogen atoms have been identified and the results compared with previous experiments and with theoretical predictions. X-ray lines from σ?p atoms may also have been observed. 相似文献
6.
Supercritical fluid extraction (SFE) of sulfur-containing soils and sediments was hindered by deposition of elemental sulfur in the restrictor stopping the flow of carbon dioxide. It was found that a copper scavenger column placed after the sample cell removed the elemental sulfur, making SF extraction and quantification possible. Conditions are described for SFE and analysis of two standard reference materials (SRM), with use of a copper scavenger column. Quantification was performed by gas chromatography with mass spectrometric detection and the results were compared with the certified SRM values. 相似文献
7.
The kinetics of the esterification of lauric acid with geraniol catalyzed by a commercially immobilized lipase preparation
fromMucor miehei, Lipozyme, was studied in well-stirred flasks under conditions of no external mass transfer limitations. It was shown that
the reaction is inhibited by lauric acid and the reaction mechanism can be described as a Ping-Pong Bi-Bi with Dead-End inhibition
caused by lauric acid. 相似文献
8.
J. Lowe S.H. Chew J.M. Nelson C.E. Waltham G.J. Pyle G.T.A. Squier S. Baird C.J. Batty P. Sharman P. Bird A.S. Clough K.R. Parker 《Nuclear Physics B》1982,209(1):16-28
The reaction K?p → Λγ, produced by K? stopping in a liquid hydrogen target, has been studied using a NaI(Tl) gamma-ray spectrometer. The branching ratio is based on 1355 events assigned to this branch. This is in conflict with a previous experiment, but agrees with one of the two published calculations, when recent values for the coupling constants and scattering amplitudes are used. 相似文献
9.
Gas chromatographic environmental analysis by direct aqueous injection (DAI) was studied for 24 volatile organic analytes (VOAs). Internal standardization was used to determine the precision of analysing these compounds by DAI. Aqueous samples were directly introduced to a gas chromatograph using fused-silica, mega-bore capillary column separation with subsequent full-scan ion trap mass spectral detection. Triplicate injections at seven levels of VOA standard solutions over a 10(3) concentration range were performed using an autosampler set up for on-column injection of 0.2 microl. Comparison of single-ion response curves to triple-ion response curves showed that triple-ion quantitation was more sensitive and precise than single-ion quantitation. Of the 24 VOAs determined at the 20 parts per billion (ppb) level, 19 and 20 were detected by the single-ion calibration and triple-ion calibration, respectively. The weighted and non-weighted regression correlation coefficients, r(2), for the 24 responses curves by the two methods, ranged from 0.910 to 0.998, with 76 of 96 being greater than 0.990. Precision, as measured by per cent relative standard deviation, was shown to be best for later eluting compounds and for higher concentrations. Analysis of an environmental sample by DAI was accomplished in 12 min and indicated the presence of benzene at 80 ppb and chlorobenzene at 2 ppm. This demonstrated the feasibility of applying this technique for screening. Several chlorinated benzenes were also detected, establishing the potential for expanding the method to include higher boiling compounds. 相似文献
10.
Energy spectra for decaying 2D turbulence in a bounded domain 总被引:1,自引:0,他引:1
We use results derived in the framework of the replica approach to study the liquid-glass thermodynamic transition. The main results are derived without using replicas and applied to the study of the Lennard-Jones binary mixture introduced by Kob and Andersen. We find that there is a phase transition due to the entropy crisis. We compute both analytically and numerically the value of the phase transition point T(K) and the specific heat in the low temperature phase. 相似文献