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排序方式: 共有305条查询结果,搜索用时 15 毫秒
31.
H Ewald O Mors T Flint U Friedrich H Eiberg TA Kruse 《Canadian Metallurgical Quarterly》1995,60(5):386-392
The effect of two cyclic enkephalin analogs (IVS-43 and IVS-46) on the group and individual behavior of rhesus macaques and hamadryas baboons has been studied. A pronounced influence of IVS-46 on competitive and operant goal-directed behavior of the monkeys was identified. 相似文献
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The purpose of this paper is to propose the necessary sampling techniques for estimating a global parameter defined in a solid opaque specimen (e.g. the total volume of mitochondria in a given liver, the total capillary surface area in a given lung, etc.). The geometry of the specimen often suggests a multi-level or cascade sampling design at different magnifications, whereby the object phase at one level becomes the reference phase in the next level. The final parameter is then estimated as the product of the intermediate ratios with the volume of the specimen, which is estimated independently. Each level can be regarded as an independent sampling design; a given stereological project may be planned in terms of one or more of these designs. Our development is a blend of practical experience and recent theoretical advances on sampling for stereology with well-known sampling techniques previously developed with different purposes in mind. 相似文献
34.
E. Wicke 《化学,工程师,技术》1977,49(9):740-740
35.
Ewald Gallei 《化学,工程师,技术》1980,52(2):99-105
Industrial application of zeolitic catalysts in hydrocracking . For maximum production of gasoline by hydrocracking using zeolite type catalysts two cracking schemes are presented and the operation conditions, feedstocks, yields, and material balances are discussed. The advantages of zeolitic hydrocracking catalysts are outlined. The main catalyst parameters controlling activity and selectivity are described and a scheme for the preparation of zeolitic catalysts is given, which illustrates the superiority of zeolitic hydrocracking catalysts over amorphous ones. Finally, the hydrocracking of residues is reviewed and a typical process together with the product characteristics and yields obtained is described. 相似文献
36.
Ewald Wicke 《化学,工程师,技术》1984,56(1):9-17
Interactions between physical and industrial chemistry. The most important interactions for the two areas of chemistry are found in the following three fields: (1)states of materials (states of aggregation) and thermodynamics; (2) kinetics of molecular processes as a basis for macroscopic models; (3) methods of testing and measurement and development of equipment. The ?classical state”? of each of these areas is first sketched out and then the principal developments which are still in course of flux; directions of future development are then deduced. Such directions are exposed to be: extension of the scope of application of supercritical states as solvents and reaction media, as part of a general expansion of industrial application of elevated pressures; increase in knowledge of nonlinear dynamics of chemical systems with regard to transient behaviour and control mechanisms; increase in basic research on molecular structure and dynamics at the interfaces of dispersed systems – especially micelles and catalyst surface – using ?in situ”? methods, and more extensive utilization of the results in industrial chemistry. 相似文献
37.
Stefan Porschen Bert Randerath Ewald Speckenmeyer 《Annals of Mathematics and Artificial Intelligence》2005,43(1):173-193
Let F = C
1 C
m
be a Boolean formula in conjunctive normal form over a set V of n propositional variables, s.t. each clause C
i
contains at most three literals l over V. Solving the problem exact 3-satisfiability (X3SAT) for F means to decide whether there is a truth assignment setting exactly one literal in each clause of F to true (1). As is well known X3SAT is NP-complete [6]. By exploiting a perfect matching reduction we prove that X3SAT is deterministically decidable in time O(20.18674n
). Thereby we improve a result in [2,3] stating X3SAT O(20.2072n
) and a bound of O(20.200002n
) for the corresponding enumeration problem #X3SAT stated in a preprint [1]. After that by a more involved deterministic case analysis we are able to show that X3SAT O(20.16254n
).An extended abstract of this paper was presented at the Fifth International Symposium on the Theory and Applications of Satisfiability Testing (SAT 2002). 相似文献
38.
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This article gives a survey of the actual experience with the relatively new technique of photo-emission electron microscopy. After describing the principal technique and the features of a modern high resolution instrument, the questions of image generation, contrast formation and resolution are considered. In particular the influence of the depth of information on resolution for flat polished sections is studied and some comparisons with the scanning electron microscope (SEM) are made.* The different fields of application of the photo-EEM are shown by examples. 相似文献