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Micron Scale (micron + scale)
Selected AbstractsDetermination of Mechanical Properties of Copper at the Micron Scale,ADVANCED ENGINEERING MATERIALS, Issue 11 2006D. Kiener Using a focused ion beam workstation, micron-sized bending and compression samples were fabricated from a pure copper single crystal. The bending and compression experiments exhibited a strong size effect on the flow stress of copper, reaching values in the order of 1,GPa for the smallest test structures. Conventional strain gradient plasticity approaches are not capable of explaining this behaviour. The surface damage introduced by Ga+ ion implantation during focused ion beam preparation was investigated using Auger electron spectroscopy and its consequence on the mechanical response of the miniaturized test samples is addressed. [source] Non-uniform plastic deformation of micron scale objectsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2003Christian F. Niordson Abstract Significant increases in apparent flow strength are observed when non-uniform plastic deformation of metals occurs at the scale ranging from roughly one to ten microns. Several basic plane strain problems are analysed numerically in this paper based on a new formulation of strain gradient plasticity. The problems are the tangential and normal loading of a finite rectangular block of material bonded to rigid platens and having traction-free ends, and the normal loading of a half-space by a flat, rigid punch. The solutions illustrate fundamental features of plasticity at the micron scale that are not captured by conventional plasticity theory. These include the role of material length parameters in establishing the size dependence of strength and the elevation of resistance to plastic flow resulting from constraint on plastic flow at boundaries. Details of the finite element method employed in the numerical analysis of the higher order gradient theory will be discussed and related to prior formulations having some of the same features. Copyright © 2003 John Wiley & Sons, Ltd. [source] Optical Properties of Skin Gloss and Development of a »Mizumizushii« Look Makeup FoundationINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006H. Nishimura In Japan, the term »mizumizushii« is used to describe a quality of »beauty«. We studied »apparently mizumizushii -looking skin« and tried to develop makeup products that »make the skin look mizumizushii« which is one of the characteristics of beauty. To accomplish this what constitutes »mizumizushii -looking skin« and »non mizumizushii -looking skin« first had to be defined. Hence, sensory evaluations were performed on 100 women. The results showed that these panelists could be classified into two groups: 25 women »having mizumizushii -looking skin« and 75 women »having skin without a mizumizushii look«. Further, it was revealed that the »skin without a mizumizushii look« could be classified into two groups, those with dry-looking skin and those with excessively oily-looking skin. We then succeeded in qualitatively classifying the appearance of the skin of these three groups on the basis of the difference in a value obtained for optical properties analyzed under specified conditions. Moreover, results of studies on possible qualitative classification of these groups using Z1, the newly discovered optical parameter for optical properties of the skin, showed an apparent relationship with the surface morphology (homogeneity on a micron scale). Based on the findings on the optical properties of »mizumizushii -looking skin«, we designed a makeup film imparting the »mizumizushii look«, which in turn led to the development a »mizumizushii look« makeup foundation. [source] Micropipette manipulation: A technique to evaluate the stability of water-in-oil emulsions containing proteinsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2004Lene Jorgensen Abstract The interfacial properties and stability of water-in-oil emulsions containing protein were studied using micromanipulation. Micropipettes were used to produce individual water droplets in oil in a controlled manner on the micron scale. The pipettes were then used to bring two droplets into contact in order to observe fusion. The occurrence of fusion was investigated as a function of the compositions of both the continuous (oil) and dispersed (aqueous) phases. Various proteins, i.e., insulin, growth hormone, or serum albumin, were dissolved in the dispersed phase. When low concentrations of surfactants or no surfactant were present in the oil phase, a condensed protein film was formed at the surface of the droplets, which was revealed by the irregular topology of the droplet surface viewed with contrast microscopy. At higher surfactant concentrations, this topology was not observed nor was the stability apparently affected; emulsion droplets coalesce immediately upon contact with each other. There seems to be a limiting surfactant concentration, which stabilizes the droplets toward fusion and prevents formation of a condensed surface film, when the droplets contain protein. The technique exhibits potential for examination of the effects of various excipients on the coalescence stability of emulsion droplets. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2994,3003, 2004 [source] Preparation of Core-shell Microspheres by ATRP Synthesized MacromonomerCHINESE JOURNAL OF CHEMISTRY, Issue 10 2008Hong CHU Abstract Poly(tert -butyl methacrylate) macrointermediates (PtBMA-Br) with an end of bromine atom were synthesized by atom transfer radical polymerization using ethylbromopropionate as an initiator in bulk in the presence of N,N,N,,N,,,N,, -pentamethyl diethylenetriamine (PMDETA) as a single ligand. A new macromonomer (MAA- PtBMA) was successfully prepared via end-group nucleophilic substitution with methacrylic acid to attain a high efficiency of C=C incorporation. The molecular weights of MAA-PtBMA macromonomers were controllable from 5400 to 11000 g/mol, and the molecular weight distribution was narrow (,1.20). Then, the PtBMA graft polystyrene (PtBMA-g-PSt) microspheres were prepared by dispersion copolymerization of MAA-PtBMA macromonomers with styrene using 2,2,-azobisisobutyronitrile as a free radical initiator in ethanol. The resulting PtBMA-g-PSt microspheres were regulated in diameter on a micron scale. [source] | ||||||||||