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41.
Summary GC-MS analysis of hydrocarbons, thermally mobilized from rock and coal samples (“thermodesorption”) at 320°C, provides valuable
and readily available information of organic geochemical significance. Two oil shale and three coal samples of different rank
have been selected for this study. The molecular patterns of compound classes of various saturated and aromatic hydrocarbons
are recorded here by employing mass chromatography of selected ions. The method described is of particular importance for
the detection of those volatile constituents in coals and sedimentary rocks, which are usually not recovered during elaborate
workup procedures (i.e. solvent extraction, liquid chromatography) due to evaporation losses. 相似文献
42.
Lobert M Thijs HM Erdmenger T Eckardt R Ulbricht C Hoogenboom R Schubert US 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(33):10396-10407
We present a detailed systematic study of the synthesis and ability of fluorinated 2-phenyl-2-oxazolines to undergo polymerization. The synthesis of these compounds is based on a two-step procedure that gives the desired 2-oxazolines in moderate-to-good yields. All the compounds were fully characterized by IR and NMR ((1)H, (13)C, and (19)F) spectroscopy, mass spectrometry, and elemental analysis. The 2-oxazolines were subsequently used as monomers for living cationic ring-opening polymerization (CROP) with microwave irradiation as the heat source (T=140 degrees C), nitromethane as the solvent, and methyl tosylate as the initiator. The linear first-order kinetic plots of the polymerizations accompanied by a linear increase of the molecular weight with conversion and low polydispersity index (PDI) values (generally below 1.30) indicate a living polymerization mechanism. The resulting polymerization rates reflect a strong sensitivity to the quantity of fluorine substituents in general and the presence or absence of ortho-fluoro substituents of the phenyl ring in particular. All the polymers were isolated and characterized by size-exclusion chromatography and MALDI-TOF mass spectrometry. Finally, a detailed investigation of selected polymer properties was performed by using differential scanning calorimetry, thermogravimetric analysis, and contact-angle measurements, thus resulting in structure-property relationships. Whereas the thermal properties of the polymers are mostly influenced by the presence of ortho-fluoro substituents, the surface properties are mainly determined by the presence of para- and/or meta-fluoro substituents. 相似文献
43.
V. Eckardt H.J. Gebauer P. Joos H. Meyer B. Naroska D. Notz W.J. Podolsky G. Wolf S. Yellin G. Drews H. Nagel E. Rabe 《Physics letters. [Part B]》1973,43(3):240-244
Production and decay characteristics of electroproduced rho mesons were studied in the final state epπ+π?. 相似文献
44.
Adams MR Aïd S Anthony PL Baker MD Bartlett J Bhatti AA Braun HM Busza W Conrad JM Coutrakon G Davisson R Derado I Dhawan SK Dougherty W Dreyer T Dziunikowska K Eckardt V Ecker U Erdmann M Eskreys A Figiel J Gebauer HJ Geesaman DF Gilman R Green MC Haas J Halliwell C Hanlon J Hantke D Hughes VW Jackson HE Jaffe DE Jancso G Jansen DM Kaufman S Kennedy RD Kirk T Kobrak HG Krzywdzinski S Kunori S Lord JJ Lubatti HJ McLeod D Magill S Malecki P Manz A Melanson H Michael DG Mohr W Montgomery HE 《Physical review D: Particles and fields》1993,48(11):5057-5066
45.
Franziska C. Vogl Sebastian Mehrl Leonhard Heizinger Inga Schlecht Helena U. Zacharias Lisa Ellmann Nadine Nürnberger Wolfram Gronwald Michael F. Leitzmann Jerome Rossert Kai-Uwe Eckardt Katja Dettmer Peter J. Oefner GCKD Study Investigators 《Analytical and bioanalytical chemistry》2016,408(29):8483-8493
46.
F. E. Eckardt 《Mathematische Annalen》1876,10(2):227-272
Ohne ZusammenfassungWir entnehmen diese letzte Arbeit des verstorbenen Verfassers dem Oster-programm 1875 der Realschule I. Ordnung zu Chemnitz. 相似文献
47.
Eckardt Johanning Paul Landsbergis Siegfried Fischer Eberhard Christ Benno Göres Raymond Luhrman 《Journal of sound and vibration》2006,298(3):594-600
US locomotive operators have exposure to multi-axis whole-body vibration (WBV) and shocks while seated. This study assessed operator-related and ergonomic seating design factors that may have confounding or mitigating influence on WBV exposure and its effects. Vibration exposure was measured according to international guidelines (ISO 2631-1; 1997); ergonomic work place factors and vibration effects were studied with a cross-sectional survey instrument distributed to a randomly selected group of railroad engineers (n=2546) and a control group; and during vehicle inspections. The survey response rate was 47% for the RR engineers (n=1195) and 41% for the controls (n=323). Results of the mean basic vibration measurements were for the x, y, z-direction and vector sum 0.14, 0.22, 0.28 and 0.49 m/s2 respectively; almost all crest factors (CF), MTVV and VDV values were above the critical ratios given in ISO 2631-1. The prevalence of serious neck and lower back disorders among locomotive engineers was found to be nearly double that of the sedentary control group without such exposure. Railroad engineers rated their seats mostly unacceptable regarding different adjustment and comfort aspects (3.02-3.51; scale 1=excellent to 4=unacceptable), while the control group rated their chairs more favorably (1.96-3.44). Existing cab and seat design in locomotives can result in prolonged forced awkward spinal posture of the operator combined with WBV exposure. In a logistic regression analysis, time at work being bothered by vibration (h/day) was significantly associated with an increased risk of low back pain, shoulder and neck pain, and sciatic pain among railroad engineers. Customized vibration attenuation seats and improved cab design of the locomotive controls should be further investigated. 相似文献
48.
49.
J. B?chler J. Bartke H. Bialkowska R. Bock R. Brockmann P. Buncic S. I. Chase I. Derado V. Eckardt J. Eschke et al. 《Zeitschrift fur Physik C Particles and Fields》1991,52(2):239-263
Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed. 相似文献
50.