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排序方式: 共有216条查询结果,搜索用时 15 毫秒
1.
Summary This paper presents an investigation of the dependence of harmonic-like topological constraints in entangled and moderately crosslinked polymer networks on segment and crosslink density and on the deformation of the sample. The approach is an extension of a theory developed for the highly crosslinked case and for polymer melts. The results are used to discuss the influence of topological constraints on the mechanical properties of different types of rubberelastic networks. 相似文献
2.
In the field of flue gas cleaning, active coke plays an important role as adsorbant and catalyst. In the temperature range usually prevailing downstream of the air preheater of power plants, SO2 becomes adsorbed on carbonaceous materials and in a consecutive step is catalysed by the carbonaceous surface and converted to sulphuric acid. The quality demands for a cyclic regenerative process for SO2 removal are fulfilled by the active coke which is used in the BF-process. The same active coke catalyses the reaction of NO with NH3 to N2 and steam. This is the basis for processes for simultaneous SO2 and NOx removal. By the addition of ammonia the SO2 removal by active coke is improved. Two processes are described and results from the laboratory and from the demonstration plant for the BF-process are presented. These show that SO2 removal efficiences exceed 95% and NO conversions of > 80% can be realized without problems. The cost of the processes using active coke with ammonia addition are comparable with those of wet flue gas desulphurization processes without any additional equipment should NO have to be removed. 相似文献
3.
Ekkehard Diedrich 《Datenschutz und Datensicherheit - DuD》2011,35(1):72-73
DuD ReportVeranstaltungsbesprechungen
Stefan Hügel transparenz.arbeit.kontrolle, Gemeinsame Jahrestagung von FIfF und DVD K?ln, 5.–7. November 2010 相似文献4.
Bert Schlatterer und Ekkehard Weiset 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1982,175(6):392-398
Zusammenfassung Es wird über Sulfonamidbefunde in Nieren und Muskulatur geschlachteter Tiere (36 Rinder, 3 Schweine) berichtet. Gewebeproben wurden vor und nach der Gewebefraktionierung mit einem durch Trimethoprim modifizierten Hemmstofftest (Teststamm:Bac. subtilis BGA) auf Hemmaktivität sowie mit einer dünnschichtchromatographischen Methode (DC) auf Sulfonamide untersucht. Als Indikatorreakti on für die Darstellung der Sulfonamide diente deren Derivatisierung mit Fluorescamin (Fluram) nach zweidimensionaler Trennung. Insgesamt wurden 11 verschiedene Sulfonamide identifiziert. An Hand von Dosis-Wirkungsbeziehungen wurde gezeigt, daß das mit Trimethoprim modifizierte Testsystem mit Ausnahme der enteral angewandten und kaum absorbierbaren Substanzen allen sonst untersuchten Sulfonamiden gegenüber mittel- bis hochgradig sensitiv ist. Hierbei liegt die minimale Hemmkonzentration im Agarlochtest (50 l) zwischen 10 und 25 Nanogramm je Sulfonamid. Der Vergleich der Ergebnisse von mikrobiologischem Test und chemischer Analyse zeigte bei dem vorliegenden Untersuchungsmaterial, daß knapp 30% der mit dem modifizierten Hemmstofftest positiv reagierenden Nierenproben aufgrund des DC-Befundes nicht als sulfonamidhaltig anzusehen waren, während umgekehrt bei den Muskelproben nahezu 30% der mit Hilfe der DC als sulfonamidhaltig erkannten Proben durch den mikrobiologischen Test nicht erfaßt wurden.
Analysis of sulfonamides in tissues of slaughtered animals. Comparison of results from a microbiological test and from thin layer chromatographic analysis after derivatization with fluorescamin
Summary Sulfonamide residues in kidneys and muscles of slaughtered animals (36 cattle, 3 pigs) are reported. Tissue samples were examined prior to and after separation first for inhibitory activity by an inhibition test modified by addition of trimethoprim and subsequently for sulfonamides by thin layer chromatography (TLC). Sulfonamides were demonstrated by derivatisation with fluorescamine (Fluram) after two dimensional separation. A total of 11 different sulfonamides was identified. It could be demonstrated by dosage-activity relationships that the test system modified with trimethoprim was moderately to highly sensitive to all examined sulfonamides with the exception of the enterally applied and hardly absorbable substances. In this test (agar diffusion test, 50 l per well) the minimal inhibotory concentration is between 10 and 25 ng for each of the sulfonamides. Comparing the microbiological test with the chemical analysis it could be demonstrated that nearly 30% of the kidney samples which were positive in the modified inhibition test did not contain sulfonamides according to interpretation of the TLC. On the other hand nearly 30% of the muscle samples containing sulfonamides (found by TLC) did not react to the microbiological test.相似文献
5.
Peter Nuhn Ekkehard Schilling Günther Wagner 《Advanced Synthesis \u0026amp; Catalysis》1976,318(2):291-297
Immunosuppressant-Antigen Conjugates. VIII. Preparation of 6-Thiopurine-Protein Conjugates by the Azide Method 6-Carboxymethyl-thiopurine was coupled with human serum albumin (HSA) and bovine serum globuline in the presence of a water soluble carbodiimide. Under these conditions, reaction of HSA with the carbodiimide led to electrophoretically detectable changes. Therefore, further conjugates were prepared by the azide method. The used azides, N-(6-benzylthiopurin- and 6-methylthiopurin-9-yl)-acetyl azide, were obtained from the hydrazides. The prepared conjugates contained upto 4.2% thiopurine, determined by spectrophotometry. It was not possible to obtain an azide from purinyl-(6)-thioacethydrazide. 相似文献
6.
The self-diffusion coefficients of polystyrene dissolved in C6D6 were measured by means of pulsed field gradient n.m.r.. The dependence on the molecular weight was of the power of -2 in accordance with the reptation model. The concentration dependence was theoretically calculated within the blob concept which shows that in the crossover region the self-diffusion coefficient is determined only by the blob dimensions and the monomeric friction coefficient is constant. The calculated concentration dependence agrees well with that observed by the authors. 相似文献
7.
The initial slope of the time-dependent scattering function and the static structure factor S(q) of macromolecules in good solvents are calculated without using the Gaussian assumption. For S(q), the scaling relation S(q)~q?1.7 is confirmed in the intermediate q range, whereas no q dependent cross-over behaviour can be observed. The calculation of reveals a q3 dependence in this range and no evidence is seen for an exponent apart from 3. The time-dependent scattering function S(q,t) is treated within the framework of the Gaussian assumption. Hydrodynamic as well as excluded volume interactions are incorporated. It has been found that excluded volume effects decrease the decay of the scattering function in comparison with the Gaussian chain. 相似文献
8.
Applications of sol-gel-processed interphase catalysts 总被引:2,自引:0,他引:2
9.
Ahmed El‐Hadi Rainer Schnabel Ekkehard Straube Gert Müller M. Riemschneider 《大分子材料与工程》2002,287(5):363-372
Poly(3‐hydroxybutyrate) (PHB) is sensitive to high processing temperatures. This leads to a decrease in molar mass as well as a lower melt viscosity. The crystallization temperature shifts to lower values, and crystallization kinetics is slow. A mixture was developed in order to improve the manufacturing properties and the final product. The blends exhibit a slight reduction in molar mass because they have a lower melting point than pure PHB, and can be extruded at their melt temperature of 170 to 180°C. Then they immediately crystallize at 125 to 100°C. Differential scanning calorimetry (DSC) shows the effect of holding time in the melt on crystallization behavior. It has been shown that the crystallization time has to be longer in the case of PHB and shorter for the blends. Thermal degradation of PHB and its blends has been investigated using thermogravimetry analysis (TG). Derivative thermogravimetry coupled with TG (TG/DTG) curves show three decomposition stages for blends at 290, 340 and 445°C, respectively. Acetic acid, water, carbon dioxide and methane are produced by degradation at a higher temperature. 相似文献
10.
Ming Zhao Chao Wang Min Guo Shiqi Peng Ekkehard Winterfeld 《Advanced Synthesis \u0026amp; Catalysis》1999,341(7):691-694
In the presence of Na2CO3 (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐3‐(1,3‐dioxo‐butyl)oxymethyl‐1,2,3,4‐tetrahydrocarboline ( 1 ) were transformed into (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐3‐hydroxymethyl‐1,2,3,4‐tetrahydrocarboline ( 2 ), which were cyclized to (6S)‐3‐acetyl‐6‐hydroxymethyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizine ( 4 ), via(6S,12bS)‐ and (6S,12bR)‐3‐acetyl‐2‐hydroxyl‐6‐hydroxymethyl‐1,2,3,4,6,7,12,12b‐octahydro‐4‐oxoindolo[2,3‐a]quinoline ( 3 ). (6S)‐ 4 was coupled with Boc‐Gly, Boc‐L‐Asp(β‐benzyl ester), or Boc‐L‐Gln to give 6‐amino acid substituted (6S)‐3‐acetyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizines 5a , 5b , or 5c , respectively. After the removal of Boc from (6S)‐ 5a (6S)‐3‐acetyl‐6‐glycyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizine ( 6 ) was obtained. The anticancer activities of (6S)‐ 5 and (6S)‐ 6 in vitro were tested. 相似文献