981 research outputs found

    Π“ΠΈΠ±Ρ€ΠΈΠ΄Π½Ρ‹ΠΉ элСктроэнСргСтичСский ΠΌΠΎΠ΄ΡƒΠ»ΡŒ

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    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

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    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

    КомплСкс гСофизичСских исслСдований скваТин с Ρ†Π΅Π»ΡŒΡŽ Ρ€Π΅ΡˆΠ΅Π½ΠΈΡ Ρ€Π°Π·Π²Π΅Π΄ΠΎΡ‡Π½Ρ‹Ρ… Π·Π°Π΄Π°Ρ‡ Π² ΠΏΡ€Π΅Π΄Π΅Π»Π°Ρ… Игольско-Π’Π°Π»ΠΎΠ²ΠΎΠ³ΠΎ нСфтяного мСстороТдСния (Вомская ΠΎΠ±Π»Π°ΡΡ‚ΡŒ)

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    Π”Π°Π½Π½Ρ‹ΠΉ ΠΏΡ€ΠΎΠ΅ΠΊΡ‚ состоит ΠΈΠ· ΡΠ»Π΅Π΄ΡƒΡŽΡ‰ΠΈΡ… частСй: ΠΎΠ±Ρ‰Π΅ΠΉ, ΠΏΡ€ΠΎΠ΅ΠΊΡ‚Π½ΠΎΠΉ, ΡΠΏΠ΅Ρ†ΠΈΠ°Π»ΡŒΠ½ΠΎΠΉ, Ρ‚Π΅Ρ…Π½ΠΈΠΊΠΎ-экономичСской. ΠžΠ±Ρ‰Π°Ρ Ρ‡Π°ΡΡ‚ΡŒ содСрТит свСдСния ΠΎ гСографичСском ΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΠΈ, климатичСских особСнностях, гСологичСских особСнностях ΠΎ Игольско-Π’Π°Π»ΠΎΠ²ΠΎΠΌ нСфтяном мСстороТдСнии. Π’ ΠΏΡ€ΠΎΠ΅ΠΊΡ‚Π½ΠΎΠΉ части производится Π²Ρ‹Π±ΠΎΡ€ ΠΎΠ±ΡŠΠ΅ΠΊΡ‚Π° исслСдования, комплСкса для провСдСния Ρ€Π°Π±ΠΎΡ‚. Π Π°ΡΡΠΌΠ°Ρ‚Ρ€ΠΈΠ²Π°ΡŽΡ‚ΡΡ: ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠ° ΠΈ Ρ‚Π΅Ρ…Π½ΠΈΠΊΠ° провСдСния гСофизичСских исслСдований, ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠ° ΠΈΠ½Ρ‚Π΅Ρ€ΠΏΡ€Π΅Ρ‚Π°Ρ†ΠΈΠΈ гСофизичСских Π΄Π°Π½Π½Ρ‹Ρ…. Π’ ΡΠΏΠ΅Ρ†ΠΈΠ°Π»ΡŒΠ½ΠΎΠΉ части рассмотрСны ΠΌΠ΅Ρ‚ΠΎΠ΄Ρ‹ Π³Π΅ΠΎΠ½Π°Π²ΠΈΠ³Π°Ρ†ΠΈΠΈ ΠΈ Ρ€ΠΎΠ»ΡŒ ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΎΠ² Π“Π˜Π‘ Π² процСссС гСологичСского сопровоТдСния бурСния, ΠΎΡ‚Π΄Π΅Π»ΡŒΠ½ΠΎ Π±Ρ‹Π» рассмотрСн ΠΌΠ΅Ρ‚ΠΎΠ΄ Π΄Π²ΡƒΠΌΠ΅Ρ€Π½ΠΎΠ³ΠΎ синтСтичСского ΠΊΠ°Ρ€ΠΎΡ‚Π°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

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    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

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    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

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    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

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    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

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    After we study the 6-dimensional N=(1,1){\cal N} = (1, 1) supersymmetry breaking and RR symmetry breaking on M4Γ—T2/ZnM^4\times T^2/Z_n, we construct two N=(1,1){\cal N} = (1, 1) supersymmetric E6E_6 models on M4Γ—T2/Z3M^4\times T^2/Z_3 where E6E_6 is broken down to SO(10)Γ—U(1)XSO(10)\times U(1)_X by orbifold projection. In Model I, three families of the Standard Model fermions arise from the zero modes of bulk vector multiplet, and the RR symmetry U(1)FIΓ—SU(2)4βˆ’U(1)_F^{I} \times SU(2)_{{\bf 4}_-} 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 N=(1,1){\cal N}=(1, 1) supersymmetric E6E_6 models on M4Γ—T2/Z4M^4\times T^2/Z_4 and M4Γ—T2/Z6M^4\times T^2/Z_6, SU(9) models on M4Γ—T2/Z3M^4\times T^2/Z_3, and SU(8) models on T2T^2 orbifolds.Comment: Latex, 33 pages, minor change

    ДинамичСский структурный Ρ„Π°ΠΊΡ‚ΠΎΡ€ для ΠΏΠ»ΠΎΡ‚Π½ΠΎΠΉ квазиклассичСской ΠΏΠ»Π°Π·ΠΌΡ‹

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    Π˜ΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ‹ ΠΈ ΠΏΡ€ΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Π½Ρ‹ динамичСскиС структурныС Ρ„Π°ΠΊΡ‚ΠΎΡ€Ρ‹ для ΠΏΠ»ΠΎΡ‚Π½ΠΎΠΉ квазиклассичСской ΠΏΠ»Π°Π·ΠΌΡ‹ Π½Π° основС псСвдопотСнциала, ΡƒΡ‡ΠΈΡ‚Ρ‹Π²Π°ΡŽΡ‰Π΅Π³ΠΎ эффСкт Π΄ΠΈΡ„Ρ€Π°ΠΊΡ†ΠΈΠΈ ΠΈ ΠΊΠΎΠ»Π»Π΅ΠΊΡ‚ΠΈΠ²Π½Ρ‹Π΅ эффСкты Π² ΡˆΠΈΡ€ΠΎΠΊΠΎΠΌ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ Ρ‚Π΅ΠΌΠΏΠ΅Ρ€Π°Ρ‚ΡƒΡ€.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΅Π½Ρ†ΠΈΠΈ Π² ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ энСргСтичСского баланса Π² элСктроэнСргСтичСских систСмах Π±ΡƒΠ΄ΡƒΡŽΡ‰Π΅Π³ΠΎ

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    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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