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131.
The development of new propellant binder systems requires the thermodynamic calculation of physico‐chemical data as well as the adaption of the mechanical properties in order to achieve a reliable innerballistic profile of the resulting propellant. Therefore, this study focuses on the mechanical properties of a binder system comprising GAP, NC as well as the energetic plasticizer DNDA and the curing agent Desmodur N100. By applying statistical methods, the mechanical properties of the binder can be predicted as a function of its composition. A macroscopic analysis of the interrelations between the E‐modulus, the ultimate tensile strength as well as the elongation at break and the specific deformation energy lead to the creation of failure master curves, which can be used as a rule of thumb criterion for the formulation of propellant binders. 相似文献
132.
Peter Offermann Thomas Engler Thomas Gries Andreas Roye 《Beton- und Stahlbetonbau》2004,99(6):437-443
Textile Reinforcement for Concrete For the best transmission of tensile and bending forces in the composite material, the textile reinforcement material has to be inserted as long fibres laid in straight orientation and depending on the load. Through the development of textile manufacturing technologies filament yarns can be manufactured into open grid structures which increase the potential of alternative reinforcements. It is currently possible to manufacture load‐adapted textile structures. It is essential that the high‐performance mechanical properties of the alkali‐resistant glass fibres or carbon fibres used are maintained throughout the manufacturing process until the finished component is complete. Therefore the quality of the yarn orientation and the yarn distribution has to be obtained secured throughout the manufacturing process until the finished textile fabric is complete. 相似文献
133.
Moo-Young Huh Hyun-Chul Kim Jong-Jin Park Olaf Engler 《Metals and Materials International》1999,5(5):437-443
In order to investigate the evolution of through-thickness texture gradients in various ferritic steel sheets, samples of
a deep drawing steel, a ferritic stainless steel and a low carbon steel were deformed by cold rolling with and without application
of a lubricant during the deformation process. The hot band texture of all samples examined showed notable through-thickness
texture gradients. The evolution of the cold rolling texture in the ferritic stainless steel and the low carbon steel in a
solution-treated state was nearly independent of the lubrication during rolling. However, in the deep drawing steel and the
as-received low carbon steel, the lubrication played an important role in the formation of the through-thickness texture gradients.
Whereas the samples rolled with lubrication showed uniform textures throughout the sheet thickness, in the samples rolled
without lubrication pronounced shear textures were observed on the sheet surface. The evolution of these through-thickness
texture gradients is discussed in terms of inhomogeneous strain states computed by an FEM model.
This article is based on a presentation made in the symposium “ ’99 International Symposium on Textures of Materials”, held
at Sunchun National University, Sunchun, April 21–22, 1999 under the auspices of The Korean Institute of Metals and Materials
and The Research and Development Center for Automobile’s Parts and Materials. 相似文献
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135.
Degradation of cationic starches and subsequent permethylation and Hofmann-elimination of the methyl-glucosides yields the corresponding enolether derivatives, which can be analyzed by GLC and GLC-MS. The relative ratio of 2-, 3- and 6-substitution in the anhydroglucose unit as well as of un-, mono-, di- and trisubstitution in the anhydroglucose unit as well as of un-, mono-, di- and trisubstituted monomers can be determined. The experimental results are compared with the data calculated by means of a kinetic model. Only slight deviations from a random distribution in the anhydroglucose unit are observed and discussed. Enzymatic degradation of the cationic starch ethers and measurement of the liberated glucose should give indication to the distribution along the polymer chain. 相似文献
136.
Optical coatings:trends and challenges 总被引:1,自引:1,他引:0
1Introduction Today,opticalcoatinghasbeenregardedas oneofthemostimportantsegmentinoptics technology[1].Itcansufficientlyimprovethe performanceofthewholeopticalsystem,satisfy thefunctionrequirements,andthereforeisan intensivelyactiveresearchfieldworldwide.Opticalcoatingscanbefoundinnearly everytechnicalapplicationstartingwithtelecom munications,spacetechnologies,andlasers.Meanwhile,itplaysasignificantroleinmany fieldsdevelopment,suchasphysics,chemistry andsynchrotronemissionapplication.Theeffi… 相似文献
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139.
In this paper we present a procedure for the selection of the minimal dc reverse bias voltage of a high-speed optically triggered sampling circuit. The optically triggered sampling circuit is based on a PIN photodiode. A set of expressions that includes the optical power dependence of the current passing through the PIN photodiode is derived. Theoretical results of the procedure are experimentally verified with practical measurements obtained from a 3 giga samples per second (GS/s) and a 20 GS/s sampling circuit implemented with commercial PIN photodiodes. Reductions in the signal-to-noise and distortion ratio of 37.28 and 6.9?dBs, as well as increments in the spurious free dynamic range of 31 and 19?dBs in the sampled signals, are respectively averted by the selection of the minimal reverse bias. 相似文献
140.
Copper island films have been prepared by thermal evaporation in vacuum and characterized by in situ as well as ex situ spectrophotometry. The parallel investigation of the island morphology by means of transmission electron microscopy allowed us to establish a clear correlation between film structure and optical properties. The effective optical constants of the copper island films could be determined by means of a fit of their ex situ transmission and reflection spectra. The effective optical constants have been used for designing and preparing optical multilayer coatings applicable for attenuator or color filter specifications. Measured characteristics of the multilayer coatings are in very good agreement with the calculated spectra. 相似文献