981 research outputs found
ΠΠΈΠ±ΡΠΈΠ΄Π½ΡΠΉ ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ ΠΌΠΎΠ΄ΡΠ»Ρ
Compression molding of glass optical components is a high volume near net-shape precision fabrication method. Residual stresses incurred during postmolding cooling are an important quality indicator for these components. In this research, residual stresses frozen inside molded glass lenses under different cooling conditions were investigated using both experimental approach and numerical simulation with a commercial finite element method program. In addition, optical birefringence method was also employed to verify the residual stress distribution in molded glass lenses. Specifically, optical retardations caused by the residual stresses in the glass lenses that were molded with different cooling rates were measured using a plane polariscope. The measured residual stress of the molded glass lenses were compared with numerical simulation as a validation of the modeling approach. Furthermore, a methodology for optimizing annealing process was proposed using the residual stress simulation results
Synthetic Biogenesis of Bacterial Amyloid Nanomaterials with Tunable Inorganic-Organic Interfaces and Electrical Conductivity
Amyloids are highly ordered, hierarchal protein nanoassemblies. Functional amyloids in bacterial biofilms, such as Escherichia coli curli fibers, are formed by the polymerization of monomeric proteins secreted into the extracellular space. Curli is synthesized by living cells, is primarily composed of the major curlin subunit CsgA, and forms biological nanofibers with high aspect ratios. Here, we explore the application of curli fibers for nanotechnology by engineering curli to mediate tunable biological interfaces with inorganic materials and to controllably form gold nanoparticles and gold nanowires. Specifically, we used cell-synthesized curli fibers as templates for nucleating and growing gold nanoparticles and showed that nanoparticle size could be modulated as a function of curli fiber gold-binding affinity. Furthermore, we demonstrated that gold nanoparticles can be preseeded onto curli fibers and followed by gold enhancement to form nanowires. Using these two approaches, we created artificial cellular systems that integrate inorganic-organic materials to achieve tunable electrical conductivity. We envision that cell-synthesized amyloid nanofibers will be useful for interfacing abiotic and biotic systems to create living functional materials.. Β© 2016 American Chemical Society
ΠΠΎΠΌΠΏΠ»Π΅ΠΊΡ Π³Π΅ΠΎΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΡΠΊΠ²Π°ΠΆΠΈΠ½ Ρ ΡΠ΅Π»ΡΡ ΡΠ΅ΡΠ΅Π½ΠΈΡ ΡΠ°Π·Π²Π΅Π΄ΠΎΡΠ½ΡΡ Π·Π°Π΄Π°Ρ Π² ΠΏΡΠ΅Π΄Π΅Π»Π°Ρ ΠΠ³ΠΎΠ»ΡΡΠΊΠΎ-Π’Π°Π»ΠΎΠ²ΠΎΠ³ΠΎ Π½Π΅ΡΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΡΠΎΡΠΎΠΆΠ΄Π΅Π½ΠΈΡ (Π’ΠΎΠΌΡΠΊΠ°Ρ ΠΎΠ±Π»Π°ΡΡΡ)
ΠΠ°Π½Π½ΡΠΉ ΠΏΡΠΎΠ΅ΠΊΡ ΡΠΎΡΡΠΎΠΈΡ ΠΈΠ· ΡΠ»Π΅Π΄ΡΡΡΠΈΡ
ΡΠ°ΡΡΠ΅ΠΉ: ΠΎΠ±ΡΠ΅ΠΉ, ΠΏΡΠΎΠ΅ΠΊΡΠ½ΠΎΠΉ, ΡΠΏΠ΅ΡΠΈΠ°Π»ΡΠ½ΠΎΠΉ, ΡΠ΅Ρ
Π½ΠΈΠΊΠΎ-ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ. ΠΠ±ΡΠ°Ρ ΡΠ°ΡΡΡ ΡΠΎΠ΄Π΅ΡΠΆΠΈΡ ΡΠ²Π΅Π΄Π΅Π½ΠΈΡ ΠΎ Π³Π΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΠΈ, ΠΊΠ»ΠΈΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΡ
, Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΡ
ΠΎ ΠΠ³ΠΎΠ»ΡΡΠΊΠΎ-Π’Π°Π»ΠΎΠ²ΠΎΠΌ Π½Π΅ΡΡΡΠ½ΠΎΠΌ ΠΌΠ΅ΡΡΠΎΡΠΎΠΆΠ΄Π΅Π½ΠΈΠΈ.
Π ΠΏΡΠΎΠ΅ΠΊΡΠ½ΠΎΠΉ ΡΠ°ΡΡΠΈ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΡΡΡ Π²ΡΠ±ΠΎΡ ΠΎΠ±ΡΠ΅ΠΊΡΠ° ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ, ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° Π΄Π»Ρ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ ΡΠ°Π±ΠΎΡ. Π Π°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ: ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠ° ΠΈ ΡΠ΅Ρ
Π½ΠΈΠΊΠ° ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ Π³Π΅ΠΎΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠ° ΠΈΠ½ΡΠ΅ΡΠΏΡΠ΅ΡΠ°ΡΠΈΠΈ Π³Π΅ΠΎΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΡ
Π΄Π°Π½Π½ΡΡ
. Π ΡΠΏΠ΅ΡΠΈΠ°Π»ΡΠ½ΠΎΠΉ ΡΠ°ΡΡΠΈ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ Π³Π΅ΠΎΠ½Π°Π²ΠΈΠ³Π°ΡΠΈΠΈ ΠΈ ΡΠΎΠ»Ρ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΠΠ‘ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠΏΡΠΎΠ²ΠΎΠΆΠ΄Π΅Π½ΠΈΡ Π±ΡΡΠ΅Π½ΠΈΡ, ΠΎΡΠ΄Π΅Π»ΡΠ½ΠΎ Π±ΡΠ» ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½ ΠΌΠ΅ΡΠΎΠ΄ Π΄Π²ΡΠΌΠ΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠ½ΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΊΠ°ΡΠΎΡΠ°ΠΆΠ°.This project consists of the following parts: general, project, special, technical and economic.
The general part contains information on the geographic location, climatic features, geological features of the Igolsko-Talovoye oil field. In the project part, a selection is made of the research object, the complex for carrying out the work. We consider: the technique and technique of conducting geophysical studies, the methodology for interpreting geophysical data. In a special part, methods of geonavigation and the role of geophysical survey methods for wells. Β in the process of geological drilling support, the two-dimensional synthetic logging method
The Mystery of Two Straight Lines in Bacterial Genome Statistics. Release 2007
In special coordinates (codon position--specific nucleotide frequencies)
bacterial genomes form two straight lines in 9-dimensional space: one line for
eubacterial genomes, another for archaeal genomes. All the 348 distinct
bacterial genomes available in Genbank in April 2007, belong to these lines
with high accuracy. The main challenge now is to explain the observed high
accuracy. The new phenomenon of complementary symmetry for codon
position--specific nucleotide frequencies is observed. The results of analysis
of several codon usage models are presented. We demonstrate that the
mean--field approximation, which is also known as context--free, or complete
independence model, or Segre variety, can serve as a reasonable approximation
to the real codon usage. The first two principal components of codon usage
correlate strongly with genomic G+C content and the optimal growth temperature
respectively. The variation of codon usage along the third component is related
to the curvature of the mean-field approximation. First three eigenvalues in
codon usage PCA explain 59.1%, 7.8% and 4.7% of variation. The eubacterial and
archaeal genomes codon usage is clearly distributed along two third order
curves with genomic G+C content as a parameter.Comment: Significantly extended version with new data for all the 348 distinct
bacterial genomes available in Genbank in April 200
Neutron star cooling: Theoretical aspects and observational constraints
The cooling theory of isolated neutron stars is reviewed. The main cooling
regulators are discussed, first of all, operation of direct Urca process (or
similar processes in exotic phases of dense matter) and superfluidity in
stellar interiors. The prospects to constrain gross parameters of supranuclear
matter in neutron-star interiors by confronting cooling theory with
observations of isolated neutron stars are outlined. A related problem of
thermal states of transiently accreting neutron stars with deep crustal heating
of accreted matter is discussed in application to soft X-ray transients.Comment: 10 pages, 3 figures, Proceedings of the 34th COSPAR Scientific
Assembly (Adv. Sp. Res., accepted
Polarons with a twist
We consider a polaron model where molecular \emph{rotations} are important.
Here, the usual hopping between neighboring sites is affected directly by the
electron-phonon interaction via a {\em twist-dependent} hopping amplitude. This
model may be of relevance for electronic transport in complex molecules and
polymers with torsional degrees of freedom, such as DNA, as well as in
molecular electronics experiments where molecular twist motion is significant.
We use a tight-binding representation and find that very different polaronic
properties are already exhibited by a two-site model -- these are due to the
nonlinearity of the restoring force of the twist excitations, and of the
electron-phonon interaction in the model. In the adiabatic regime, where
electrons move in a {\em low}-frequency field of twisting-phonons, the
effective splitting of the energy levels increases with coupling strength. The
bandwidth in a long chain shows a power-law suppression with coupling, unlike
the typical exponential dependence due to linear phonons.Comment: revtex4 source and one eps figur
Muon-spin-relaxation study of the magnetic penetration depth in MgB2
The magnetic vortex lattice (VL) of polycrystalline MgB2 has been
investigated by transverse-field muon-spin-relaxation (TF-MuSR). The evolution
of TF-MuSR depolarization rate, sigma, that is proportional to the second
moment of the field distribution of the VL has been studied as a function of
temperature and applied magnetic field. The low temperature value s exhibits a
pronounced peak near Hext = 75 mT. This behavior is characteristic of strong
pinning induced distortions of the VL which put into question the
interpretation of the low-field TF-MuSR data in terms of the magnetic
penetration depth lambda(T). An approximately constant value of sigma, such as
expected for an ideal VL in the London-limit, is observed at higher fields of
Hext > 0.4 T. The TF-MuSR data at Hext = 0.6 T are analyzed in terms of a
two-gap model. We obtain values for the gap size of D1 = 6.0 meV (2D1/kBTc =
3.6), D2 = 2.6 meV (2D2/kBTc = 1.6), a comparable spectral weight of the two
bands and a zero temperature value for the magnetic penetration depth of lambda
= 100 nm. In addition, we performed MuSR-measurements in zero external field
(ZF-MuSR). We obtain evidence that the muon site (at low temperature) is
located on a ring surrounding the center of the boron hexagon. Muon diffusion
sets in already at rather low temperature of T > 10 K. The nuclear magnetic
moments can account for the observed relaxation rate and no evidence for
electronic magnetic moments has been obtained.Comment: 15 pages, 4 figure
Gauge-Fermion Unification and Flavour Symmetry
After we study the 6-dimensional supersymmetry breaking
and symmetry breaking on , we construct two supersymmetric models on where is
broken down to by orbifold projection. In Model I, three
families of the Standard Model fermions arise from the zero modes of bulk
vector multiplet, and the symmetry
can be considered as flavour symmetry. This may explain why there are three
families of fermions in the nature. In Model II, the first two families come
from the zero modes of bulk vector multiplet, and the flavour symmetry is
similar. In these models, the anomalies can be cancelled, and we have very good
fits to the SM fermion masses and mixings. We also comment on the supersymmetric models on and ,
SU(9) models on , and SU(8) models on orbifolds.Comment: Latex, 33 pages, minor change
ΠΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΡΡΡΠΊΡΡΡΠ½ΡΠΉ ΡΠ°ΠΊΡΠΎΡ Π΄Π»Ρ ΠΏΠ»ΠΎΡΠ½ΠΎΠΉ ΠΊΠ²Π°Π·ΠΈΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»Π°Π·ΠΌΡ
ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ ΠΈ ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΡΡΡΠΊΡΡΡΠ½ΡΠ΅ ΡΠ°ΠΊΡΠΎΡΡ Π΄Π»Ρ ΠΏΠ»ΠΎΡΠ½ΠΎΠΉ ΠΊΠ²Π°Π·ΠΈΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»Π°Π·ΠΌΡ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΏΡΠ΅Π²Π΄ΠΎΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»Π°, ΡΡΠΈΡΡΠ²Π°ΡΡΠ΅Π³ΠΎ ΡΡΡΠ΅ΠΊΡ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠΈ ΠΈ ΠΊΠΎΠ»Π»Π΅ΠΊΡΠΈΠ²Π½ΡΠ΅ ΡΡΡΠ΅ΠΊΡΡ Π² ΡΠΈΡΠΎΠΊΠΎΠΌ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡ.The dynamical structure factor for dense semiclassical plasma, which takes into account the diffraction effect in a wide range of densities and temperatures was investigated
Π’Π΅Π½Π΄Π΅Π½ΡΠΈΠΈ Π² ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π±Π°Π»Π°Π½ΡΠ° Π² ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ ΡΠΈΡΡΠ΅ΠΌΠ°Ρ Π±ΡΠ΄ΡΡΡΠ΅Π³ΠΎ
Recent advances in compression molding of glass optical elements for mass production offer the potential of extending this technology to elements with micro and nano scale features. In this research, glass diffractive optical elements (DOEs) with lateral features in the order of 10 mu m and vertical height of 330 nm were fabricated using a fused silica glass mold and a special low T-g (glass transition temperature) glass material K-PG325. Molded DOEs were studied using an atomic force microscope (AFM) and scanning electron microscope (SEM) to evaluate the glass molding process capability. Optical testing of the molded DOEs was a further demonstration of the effectiveness of the molding process for high volume micro and diffractive optical component fabrication. The combination of two high-precision, high-volume processes, i.e., semiconductor batch process for optical mold making and glass molding for DOE replication, is an effective alternative manufacturing method for high-quality, low-cost optical components. The reported experiment is a detailed illustration of the glass molding process capability. With further process optimization a robust manufacturing process can be developed for mass production of diffractive and micro glass optical elements
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