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11.
Koulman A Tapper BA Fraser K Cao M Lane GA Rasmussen S 《Rapid communications in mass spectrometry : RCM》2007,21(3):421-428
A fast method was developed to directly infuse raw plant extracts into a linear ion trap mass spectrometer, using the ion trap to isolate and fragment as many ions as possible from the extract. The full mass spectra can be analysed by multivariate statistics to determine discriminating ions, and the fragmentation data allows rapid classification or identification of these ions. The methodology was used to screen a wide range of strains of endophytic fungi in perennial ryegrass seeds for differences in metabolic profiles. The results show that this newly developed methodology is able to determine discriminating ions that can be present in very low concentrations. It also yielded sufficient fragmentation data to classify or identify the discriminating ions. 相似文献
12.
本文从离轴微粒场全息记录光路的一般模型出发,导出了离轴微粒场全息术中记录介质分辨率要求的普遍公式。讨论了三种典型形状微粒对记录介质的分辨率要求。结果表明,除了参考光的倾角外,微粒的尺寸和参、物光的波前曲率差及微粒重心偏离光轴的距离也都是影响记录介质分辨率要求的主要因素。 相似文献
13.
H. Fawcett S. Barlag H. Becker E. Belau T. Böhringer M. Bosman V. Chabaud D. Bucholz V. Castillo C. Damerell C. Daum G. De Rijk H. Dietl S. Gill A. Gillman R. Gilmore T. Gooch P. Gras Z. Hajduk E. Higon B. Hyams D. Kelsey J. Kemmer R. Klanner U. Kötz S. Kwan B. Lücking G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Palka M. Pepe G. Polok J. Richardson M. Rozanska K. Rybicki H. Seebrunner U. Stierlin R. Tapper H. Tiecke M. Turala G. Waltermann S. Watts P. Weilhammer F. Wickens L. Wiggers A. Wylie T. Zeludziewicz ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):521-524
Data on the production of the neutralK *(892) resonances at lowp t by 200 GeVK ? and π? is compared with the predictions of various models based on the quark parton model of hadrons. 相似文献
14.
C. Daum L.O. Hertzberger W. Hoogland R.T. Jongerius G. Polok W. Spierenburg H.G. Tiecke L.W. Wiggers D.G. Bardsley J. Malos R.J. Tapper R.J. Whyley M. Bosman M. Cerrada V. Chabaud B. Hyams J.C. Vermeulen F. Wickens 《Physics letters. [Part B]》1981,104(3):246-250
Inclusive øø production has been studied in π?-Be interactions for 100 and 175 GeV incident momentum. An upper limit of 72 nb has been set for . At both momenta the number of øø events is larger than expected for uncorrelated ø pairs. A narrow width enhancement is observed at Møø≈2100 MeV with a 4 standard deviation significance. 相似文献
15.
C. Marchioni E. Riccardi S. Spinelli F. DellUnto P. Grimaldi A. Bedini C. Giliberti L. Giuliani R. Palomba A. Congiu Castellano 《Ultrasonics》2009,49(6-7):569-576
The structural effect induced by therapeutic ultrasound on proteins in aqueous solution has been investigated with FTIR spectroscopy, UV–VIS spectroscopy, circular dichroism and light scattering. Six proteins (cytochrome, lysozyme, myoglobin, bovine serum albumin, trypsinogen, and α-chymotrypsinogen A) with different molecular weight and secondary structure have been studied. The experiment has been performed using an ultrasound source at resonant frequency of 1 MHz and sonication times of 10, 20, 30, 40, 50, and 60 min. A different behaviour of proteins under sonication depends on the dominant secondary structure type (α-helix or β-sheets) and on the grade of the ordered structure. The results suggest that the free radicals, produced by water sonolysis, have an important role in the changes of structural order. 相似文献
16.
M. Miettinen M. Johansson S. Suvanto J. Riikonen U. Tapper T. T. Pakkanen V.-P. Lehto J. Jokiniemi A. Lähde 《Journal of nanoparticle research》2011,13(10):4631-4645
Silicon–carbon nanoceramics have been synthesised from hexamethyldisilane (HMDS) by the atmospheric pressure chemical vapour
synthesis (APCVS). Direct aerosol phase synthesis enables continuous production of high purity materials in one-stage process.
The particle formation is based on the decomposition of the precursor in a high temperature reactor. Reaction of the gas phase
species leads to homogeneous nucleation and formation of the nanoparticles with a narrow size distribution (geometric mean
diameter range of particle number size distribution 160–200 nm with 1.5–1.6 geometric standard deviation at reaction temperatures
800–1200 °C). A systematic investigation of the influence of the process temperature on the powder characteristics, including
the particle size, crystallinity, chemical structure, surface and bulk composition and surface morphology, was carried out.
At the reactor temperature of 800 °C, the synthesised nanoparticles were amorphous preceramics containing mostly SiC4, Si–CH2–Si and Si–H units. The composition of the powder turned towards nanocrystalline 3C–SiC (crystal size under 2 nm) when the
reaction temperature was increased to 1200 °C. The reaction temperature appeared to be a key parameter controlling the structure
and properties of the synthesised powders. 相似文献
17.
B.J. Charles I.M. Cowan T.R.M. Edwards W.M. Gibson A.R. Gillman R.S. Gilmore M.H. Gledhill C.M. Hughes J. Malos A.C. McPherson J.C. Sleeman V.J. Smith R.J. Tapper B. McCartney G.C. Oades D.L. Ward P.D. Wroath G.A. Beck S.G.F. Frank 《Nuclear Physics B》1977,131(1):7-53
Differential cross sections for elastic K+p scattering have been measured at nineteen momenta between 0.7 and 1.9 GeV/c. The data represent between 10 thousand and 20 thousand elastic events at each momentum and cover a wide range of scattering angles (). A computer controlled system of scintillation counters and acoustic spark chambers was used to detect the elastic events. Various internal consistency checks indicate that the absolute normalization of the data is accurate to within 2–3%. The cross sections show a smooth transition from an isotropic angular distribution to a dominant forward peak over the range covered by the experiment. Phase-shift analyses including these results show little evidence for a direct-channel resonance, and fitting the results by t- and u-channel exchange processes alone gives a good fit. 相似文献
18.
Tapper AE Long JR Staples RJ Stavropoulos P 《Angewandte Chemie (International ed. in English)》2000,39(13):2343-2346
19.
In the present paper we compare the response of two types of photoacoustic cells (resonant and nonresonant) to determine the amount of ammonia volatilized from biological liquid samples at constant temperature, pressure and pH. The home made detector was a photoacoustic spectroscopy apparatus developed by Molecular Spectroscopy Laboratory staff at ENEA Frascati Research Centre in Italy. The sensor makes use of photo-acoustic cells equipped with commercially available high sensitivity miniaturized microphones. The radiation source was a line-tunable stabilized 10 W CW CO2 laser. Ammonia measurements were performed by tuning the laser source on the 9R30 laser line (9.2197 µm radiation wavelength). Ammonium chloride standard solutions were prepared by us in laboratory, to serve as reproducible ideal samples. The photoacoustic response of the two type of photoacoustic cells was determined and compared. The feasibility study was reported. 相似文献
20.
P.K. Schmieder R.C. Kolanczyk M.W. Hornung M.A. Tapper J.S. Denny B.R. Sheedy 《SAR and QSAR in environmental research》2014,25(4):253-287
A rule-based expert system (ES) was developed to predict chemical binding to the estrogen receptor (ER) patterned on the research approaches championed by Gilman Veith to whom this article and journal issue are dedicated. The ERES was built to be mechanistically transparent and meet the needs of a specific application, i.e. predict for all chemicals within two well-defined inventories (industrial chemicals used as pesticide inerts and antimicrobial pesticides). These chemicals all lack structural features associated with high affinity binders and thus any binding should be low affinity. Similar to the high-quality fathead minnow database upon which Veith QSARs were built, the ERES was derived from what has been termed gold standard data, systematically collected in assays optimized to detect even low affinity binding and maximizing confidence in the negatives determinations. The resultant logic-based decision tree ERES, determined to be a robust model, contains seven major nodes with multiple effects-based chemicals categories within each. Predicted results are presented in the context of empirical data within local chemical structural groups facilitating informed decision-making. Even using optimized detection assays, the ERES applied to two inventories of >600 chemicals resulted in only ~5% of the chemicals predicted to bind ER. 相似文献