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1.
We address in this paper the problem of finding an optimal strategy for dealing with bottleneck machines and bottleneck parts in the cell formation process in group technology. Three types of economic decisions are considered: subcontracting, machine duplication and intercell moves. The problem is formulated as a minimum weighted node covering problem in a hypergraph, and we show that it can be solved in polynomial time by finding a maximum weighted stable set in a bipartite graph. We extend this result to cellular manufacturing systems in which the sequence of operations of each part is known in advance. 相似文献
2.
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4.
Vladimir Rapić Prof. Dr. Karl Schlögl Brigitte Steinitz 《Monatshefte für Chemie / Chemical Monthly》1977,108(4):767-780
Starting from optically active methylferrocene-- and--carboxylic acids (1 a and1 b) of known absolute configuration and enantiomeric purity about 15 chiral ferrocenes (of each isomeric series— and ) were obtained by suitable ligand transformations. Thereby (almost) all possible chiral combinations of the ligands CH3, COOH (COO–), COOCH3, CN and NH2 (NH3
+) were accessible which are necessary for a potential test of approximations of chirality functions for compounds with basic symmetry C5v. The chiroptical properties of these disubstituted ferrocenes are recorded.Preliminary tests using a shortened Ansatz revealed large discrepancies between calculated () and found [M]D-values. Possible reasons for this failure are discussed.
61. Mitt. über Ferrocenderivate
39. Mitt.:A. Meyer, H. Neudeck undK. Schlögl, Chem. Ber.110, 1403 (1977).
60. Mitt.:V. Rapi, K. Schlögl undB. Steinitz, J. Organometal. Chem.94, 87 (1975). 相似文献
61. Mitt. über Ferrocenderivate
39. Mitt.:A. Meyer, H. Neudeck undK. Schlögl, Chem. Ber.110, 1403 (1977).
60. Mitt.:V. Rapi, K. Schlögl undB. Steinitz, J. Organometal. Chem.94, 87 (1975). 相似文献
5.
Jocelyn Jalbert Roland Gilbert Pierre Tétreault Brigitte Morin Denise Lessard-Déziel 《Cellulose (London, England)》2007,14(4):295-309
In this study, headspace gas chromatography/mass spectrometry has been used to assess the volatile by-products generated by
the ageing of oil-impregnated paper insulation of power transformers. Sealed-glass ampoules were used to age under oxidative
conditions 0.5-g specimens of insulating paper in 9 mL of inhibited mineral oil in a temperature range of 60–120 °C and moisture
of 0.5, 1 and 2% (w/w). A linear relationship between one of the oil-soluble degradation by-products, i.e. methanol, and the
number of ruptured 1,4-β-glycosidic bonds of cellulose, regardless of the type of paper (ordinary Kraft or thermally-upgraded
(TU) Kraft paper), was established for the first time in this field. Ageing at 130 °C of model compounds of the Kraft paper
constituents (α-cellulose, hemicellulose and lignin) and two cellulosic breakdown by-products (D-(+)-glucose and 1,6-anhydro-β-d-glucopyranose) confirmed that the α-cellulose degradation was mostly responsible for the presence of this molecule in the
system. Furthermore, additional 130 °C-tests with six different papers and pressboard samples under a tight control of initial
moisture indicated that at least one molecule of methanol is formed for each rupture of 1,4-β-glucosidic bond of the molecular
chains. Stability tests showed that the ageing indicator is stable under the oxygen and temperature conditions of open-breathing
transformers. The presence of methanol was detected in 94% of oil samples collected from over than 900 in-service pieces of
equipment, confirming the potential for this application. Lastly, the tests have shown that oil-oxidation by-products and
TU-nitrogenous agents modify the methanol partitioning coefficients in the paper/oil/air system, which makes their study essential
over a range of field conditions encountered by power transformers. Results are presented and discussed in comparison with
2-furfuraldehyde, which is the current reference in the domain. 相似文献
6.
Gerhard Buchbauer Waltraud Pernold Dorothea Rassl Brigitte Blach 《Monatshefte für Chemie / Chemical Monthly》1981,112(4):517-527
The synthesis of some new potentially, nitrogenefree spasmolytics is described. Formally the benzene nucleus in some mandelic acid esters, known by their mild spasmolytic activity, is substituted for the isocamphane bicyclus by a) SeO2 oxidation of 1-(3,3-Dimethyl-2-exo-norbornyl)-ethanone (5) to the corresponding ketoaldehyde6, b) oxidation of6 to the isocamphane analogous mandelic acid4 and c) esterification of derivatives of4 with isoamylalcohol and benzylalcohol. Attemps to dehydrate the methylester7 to camphenylideneacetic acid methylester (12) by various methods failed, probably because of the ring strain.
Teil der Diplomarbeit vonB. Blach, Universität Wien 1981. 相似文献
7.
Mono- or 1,1′-bis-acylation of ferrocene, its mono and 1,1′-dimethyl and phenyl derivatives and of [3]ferrocenophane with o-chlorobenzoyl chloride/AlCl3 affords the corresponding (isomeric) chlorobenzoyl ferrocenes in high yields which can be separated by column, layer or high pressure liquid chromatography and in the case of the monomethylferrocene monoketones also by crystallization. The cleavage of the (o-chlorobenzoyl)ferrocenes by potassium-t-butoxide (and traces of water) yields the corresponding ferrocene carboxylic acids except for the α-phenyl derivatives in almost quantitative yields, thus offering a very convenient access to these acids. In all cases the isomer distribution and thereby the relative site reactivities were determined. 相似文献
8.
The In-flame detector earlier applied to the specific chlorine (359.9 nm) and bromine (372.7 nm) analysis has now been employed for the iodine determination at 409.9 nm. It is shown that the resolution power of a GC column can be improved by such a specific detector. After calibration quantitative measurements of the iodine contents of the GC fractions are possible. The detection limits are 0.01–1.4 μg of iodine. 相似文献
9.
A nonradioactive method was employed to detect different cell membrane antigens on human polymorphonuclear granulocytes, monocytes and platelets. We compared the reactivity of one monoclonal antibody, N1III10, assumed to be FcγRII-specific by functional assays, with other well-characterized monoclonal antibodies and human sera. Intact cells were incubated with biotin N-hydroxysulfosuccinimide ester which preferentially reacts with lysine residues in polypeptides. Biotin-labeled cells were lysed and the antigen was isolated from the cell lysate by immunoprecipitation with the antibody bound to Protein A-Sepharose. The precipitates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane, and visualized by a streptavidin-alkaline phosphatase system with a suitable substrate. Using this biotin-labeling system we could show that N1III10 detects a 40 kDa antigen on monocytes and platelets, comparable to that expected of FcγRII monoclonal antibodies. 相似文献
10.