Ruled Surfaces
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. HÉLICES, CURVAS DE BERTRAND E SUPERFÍCIES REGRADAS / HELICES, BERTRAND CURVES AND RULED SURFACES
O presente trabalho destina-se a um estudo sobre hélices e curvas de Bertrand. Uma hélice circular é caracterizada por ter curvatura k 6= 0 e torção t constantes. Se a razão t k for constante, a curva é chamada hélice generalizada. Uma curva g : I −→ R3 é chamada curva de Bertrand se existe uma outra curva g : I −→ R3 tal que
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2012
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2. Superfícies Regradas de Bonnet / Superfícies Regradas de Bonnet / Bonnet Ruled Surfaces / Bonnet Ruled Surfaces
Neste trabalho, mostraremos que uma superfície é de Bonnet se, e somente se for uma Anet, apresentado no trabalho Soyuçok [6]. Usando este resultado estudamos as Superfícies Regradas de Bonnet, baseado no trabalho de Kanbay [1].
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/03/2011
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3. CYCLIC MINIMAL SURFACES IN R3, S2 X R AND H2 X R / SUPERFÍCIES MÍNIMAS CÍCLICAS EM R3, S2 X R E H2 X R
In this work we describe minimal surfaces embedded in product spaces M x R, where M = R2, S2 and H2 which are foliated by geodesics (ruled surfaces) and curves of M with constant curvature (cyclic surfaces). In R2 x R, i.e. R3, we shall prove that there exist only two minimal cyclic surfaces which are the catenoid and the Riemann example. Then we characteriz
Publicado em: 2007
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4. Modification of plasma polymer films by ion implantation
In this work, thin polymer films were prepared from acetylene and argon radiofrequency (13.56 MHz, 80 W) glow discharges. Post-deposition treatment was performed by plasma immersion ion implantation in nitrogen or helium glow discharges (13.56 MHz, 70 W). In these cases, samples were biased with 25 kV negative pulses. Exposure time to the bombardment plasma,
Materials Research. Publicado em: 2004-09
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5. Attachment Stimulates Exopolysaccharide Synthesis by a Bacterium
This study examined the hypothesis that solid surfaces may stimulate attached bacteria to produce exopolymers. Addition of sand to shake-flask cultures seemed to induce exopolymer synthesis by a number of subsurface isolates, as revealed by optical microscopy. Several additional lines of evidence indicated that exopolymer production by attached cells (in con
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6. Differentiation of Serratia marcescens 274 into swimmer and swarmer cells.
We describe a new sensory response in the enteric bacterium Serratia marcescens. When grown in liquid media, the bacteria were short rods with one to two flagella and displayed classical swimming behavior. Upon transfer to a solid surface (0.7 to 0.8T% agar medium), the bacteria underwent a dramatic change of form. They ceased septation, elongated, and expre
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7. DNA binding to mica correlates with cationic radius: assay by atomic force microscopy.
In buffers containing selected transition metal salts, DNA binds to mica tightly enough to be directly imaged in the buffer in the atomic force microscope (AFM, also known as scanning force microscope). The binding of DNA to mica, as measured by AFM-imaging, is correlated with the radius of the transition metal cation. The transition metal cations that effec