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31.
E. Aust W. Limberg R. Gerling B. Oger Th. Ebel 《Materialwissenschaft und Werkstofftechnik》2005,36(9):423-428
Complex titanium bone screw fabricated by metal injection moulding M etal I njection M oulding (MIM) is a recently developed powder metal forming technology which is ideally suited to manufacture small geometrically complex parts from alloy powders. This innovative technology was used to fabricate a complex bone screw using metal powder of the biological inert Ti Al6 Nb7 alloy. This article presents the MIM‐technical boundary conditions to produce the screw and results of mechanical and chemical screw tests which qualify this injection moulded part as an advanced implant. 相似文献
32.
33.
U. Götze Th. Weber C. Linke A. Schmidt 《Materialwissenschaft und Werkstofftechnik》2009,40(7):566-572
Target Costing for Materials – Potentialities and Methodology Target Costing is a standard instrument of cost management in business administration, but hardly mentioned in the economic oriented literature on material sciences. Nevertheless there are high potentialities for developers, producers, or users of materials regarding the improvement of efficiency. Therefore, this article will present these potentialities of a material oriented Target Costing. Besides, the general methodology of Target Costing will be modified to meet the specifics of materials from the perspectives of users of materials on the one hand and developers respectively producers of materials on the other. 相似文献
34.
G. Alisch Dr. B. Wielage S. Steinhäuser Th. Lampke H. Podlesak D. Nickel 《Materialwissenschaft und Werkstofftechnik》2008,39(1):58-65
Process for anodizing of aluminum stripes with high electrical breakdown voltage The Aim of the research was to develop an anodizing process for generating a high breakdown voltage on aluminum stripes in the shortest processing time possible. In order to vary process parameters in a wide range, a flexible discontinuous anodizing laboratory device was designed in cooperation with Steinert Elektromagnetbau GmbH Köln. By means of the liquid contact method, conditions equal to non‐solid contact anodizing of aluminum stripes in continuous laboratory devices were simulated. The research was focused on the development of the current pulse shape. The results show that the highest possible breakdown voltages can be achieved in a short processing time using suitable electrical parameters (current pulse shape) and the appropriate post‐treatment. The films generated by the new technology (current pulse shape referred to as “TUCAL”) reveal a higher pore density than conventional layers. This results in a higher ductility (less tendency for cracking). 相似文献
35.
Th. Lampke Prof. M. Zacher D. Dietrich B. Wielage 《Materialwissenschaft und Werkstofftechnik》2008,39(12):897-900
Deposition and structure of electroplated composite layers The electrodeposition of nickel layers with incorporated ceramic nanoparticles, TiO2 and Al2O3 was carried out with the aid of ultrasound during electroplating. The ultrasound guarantees a permanent desagglomeration of nanoparticles in the electrolyte. Therefore, nanoparticles were incorporated homogeneously and fine‐dispersedly. The incorporation of nanoscaled particles, the changes of the layer structure and the crystallites were investigated in comparison to conventionally electrodeposited nickel layers by means of SEM, EDX, EBSD and XRD. 相似文献
36.
Th. Pretorius G. Habedank J. Woitschig F. Vollertsen 《Materialwissenschaft und Werkstofftechnik》2006,37(1):85-91
Thermal treatments of steel components with the goal of hardening often result in distortion by releasing the residual stresses which were brought into the specimen during the preceding processing steps. The goal of the presented work is the minimization of this distortion. By generating definite residual stress fields and investigating the resulting distortion, the distortion mechanism can be observed in detail. A flexible and reproducible way to generate such residual stress fields inside a specimen is by means of local thermal treatment with a laser beam. Computer simulations as well as experiments were carried out using an idealized tooth of a gearwheel (finger sample) as a model system. The deformation of the samples due to the laser heat treatment and the stress fields generated inside the samples were determined with respect to different process parameters. 相似文献
37.
P Leterme A Théwis E Fran?ois P Van Leeuwen B Wathelet J Huisman 《Canadian Metallurgical Quarterly》1996,126(9):2188-2198
We assessed the use of 15N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary N excretion pattern at the ileum subsequent to the ingestion of a single 15N-labeled meal. In a second experiment, we compared ileal endogenous AA outputs and true AA digestibility estimates obtained in pigs ingesting 15N-labeled dietary proteins in a single meal vs. intravenous infusion of [15N]leucine for 10 d during the ingestion of a pea-based diet and a protein-free starch diet. The proportion of endogenous N found in the ileal digesta differed when the label was delivered orally (50%) vs. intravenously (72%) and changed with time. As a consequence, the true ileal AA digestibilities measured with labeled diets were lower. A third experiment demonstrated that this was due to the rapid recycling of labeled dietary N in endogenous moieties, because 15N was found in blood within 10 min of consuming the labeled meal, within 50 min of consumption in pancreatic enzymes, 90 min in bile and 4 h in ileal mucins. We conclude that the use of 15N-labeled meals for determination of true ileal AA digestibilities is limited by the fast recycling of dietary N in endogenous secretions following a single 15N-labeled meal. The accuracy of results will depend on meaningful estimates of AA flow during a limited period and accurate estimates of 15N in AA. 相似文献
38.
Veronese I Cantone MC Giussani A Maggioni T Birattari C Bonardi M Groppi F Garlaschelli L Werner E Roth P Höllriegl V Louvat P Felgenhauer N Zilker T 《Radiation protection dosimetry》2003,105(1-4):209-212
The interest in the biokinetics of ruthenium and zirconium in humans is justified by the potential radiological risk represented by their radionuclides. Only a few data related to the biokinetics of ruthenium and zirconium in humans are available and, accordingly, the biokinetic models currently recommended by the ICRP for these elements are mainly based on data from animal experiments. The use of stable isotopes as tracers, coupled with a proper analytical technique (nuclear activation analysis with protons) for their determination in biological samples, represents an ethically acceptable methodology for biokinetic investigations, being free from any radiation risk for the volunteer subjects. In this work, the results obtained in eight biokinetic investigations for ruthenium, conducted on a total of three healthy volunteers, and six for zirconium, performed on a total of three subjects, are presented and compared to the predictions of the ICRP models. 相似文献
39.
Synthetic materials considered for biohybrid skin or other tissue engineering applications have to support cellular interaction and colonisation of implants. However, despite the number of studies reported in the literature, there is no agreement on the principal factors applicable to modulate the interaction with cells, such as the wettability of biomaterials, their surface potential and chemistry of the surface. Particularly, in this study we were interested on the impact of surface chemistry and net surface (zeta) potential on dermal fibroblasts. To address this question self assembled monolayers of silanes on glass, further derivatized with different functional groups, were used to study the adhesion and proliferation of human skin fibroblasts in response to these factors. The model surfaces were characterized using streaming potential (zeta potential) and water contact angle measurements. All samples were found to be negatively charged at physiological pH (regardless of the different chemistry) increasing (or equal ～) the magnitude of the negative potential in the following order: hydroxy (OH) < amine (NH2) ～ epoxy (EPOXY) < carboxyl (COOH) < three‐fluorocarbon (CF3) < sulfonic (SO3) functionalities. The interaction of fibroblast characterized by the effectiveness of cell adhesion, spreading and actin stress fibres formation decreased almost in the opposite order: NH2 > OH > EPOXY > SO3 > COOH > CF3 functions. The surfaces were found also to be highly wettable, except CF3. Interestingly, the best cellular interaction was found on the moderately wettable NH2 surface representing water contact angle (CA) of 65°, and the worst, on the least wettable CF3 surface (CA 85°) indicating that not only the surface potential but also the type of functional groups may play an important role. The organisation of α5 and β3 integrins generally followed the same trend of less clustering in focal adhesion plaques when the negative potential increased, except on SO3 surface, where β3 but not α5 integrins were greatly expressed. Cell growth however, showed a significant decrease on highly charged COOH and SO3 surfaces, as well as, on non‐polar CF3 functions. The best proliferation response was obtained on surfaces with primary amine groups. The results indicate that the surface (zeta) potential might be a critical parameter for cellular interactions, but also the substratum wettability and the type of functional groups have to be controlled in order to improve the biocompatibility of material surfaces. 相似文献
40.
K. Bach H. D. Baehr H. Bebelein A. Naumann F. W. Riegels D. Küchemann H. J. Zetzmann R. Ulken Th. Lehmann E. W. Huber E. Martyrer E. Strohbusch H. Rettig H. Meincke H. W. Hahnemann A. Steller H. Kicherer F. Frank K. Meerbeck W. Gohlke H. Weissbach J. Wotschke E. Kollmann 《Forschung im Ingenieurwesen》1963,29(5):164-168
Ohne Zusammenfassung VDI 相似文献