168 research outputs found

    Genetic data on 15 STR loci in the Caucasian population of the Russian Federation

    No full text
    Представлены популяционно-генетические данные для 15 STR локусов, входящих в систему AmpFlSTR Identifiler (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818 и FGA). Локусы получены на основании анализа 1118 неродственных лиц европеоидной расы, проживающих на территории Российской Федерации. На основании этих данных рассчитаны важные генетические параметры, которые используются при криминалистическом анализе ДНК.Наведено популяційно-генетичні дані за 15 STR локусами, що входять в систему AmpFlSTR Identifiler (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818 та FGA). Локуси отримано на основі аналізу 1118 неспоріднених осіб європеоїдної раси, що проживають на території Російської Федерації. На основі цих даних розраховано важливі генетичні параметри, які використовуються при криміналістичному аналізі ДНК.Population genetic data for the 15 STR loci included in the AmpFlSTR Identifiler kit (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818 and FGA) obtained from 1118 unrelated Caucasian individuals from the Russian Federation are presented. In addition, a number of forensically useful genetic parameters are reported

    First-principles study of Co- and Cu-doped Ni2MnGa along the tetragonal deformation path

    Get PDF
    The influence of Co and Cu doping on Ni-Mn-Ga Heusler alloy is investigated using the first-principles exact muffin-tin orbital method in combination with the coherent-potential approximation. Single-element doping and simultaneous doping by both elements are investigated in Ni50−xCoxMn25−yGa25−zCuy+z alloys, with dopant concentrations x,y, and z up to 7.5 at. %. Doping with Co in the Ni sublattice decreases the (c/a)NM ratio of the nonmodulated (NM) martensite, but it simultaneously increases the cubic phase stability with respect to the NM phase. Doping with Cu in the Mn or in Ga sublattices does not change the (c/a)NM ratio significantly and it decreases the cubic phase stability. For simultaneous doping by Co in the Ni sublattice and Cu in the Mn or Ga sublattices, the effects of the individual dopants are independent and about the same as for the single-element doping. Thus, the (c/a)NM ratio can be adjusted by Co doping while the phase stability can be balanced by Cu doping, resulting in stable martensite with a reduced (c/a)NM. The local stability of the cubic phase with respect to the tetragonal deformation can be understood on the basis of a density-of-states analysis.Peer reviewe

    A two dimensional model for ferromagnetic martensites

    Full text link
    We consider a recently introduced 2-D square-to-rectangle martensite model that explains several unusual features of martensites to study ferromagnetic martensites. The strain order parameter is coupled to the magnetic order parameter through a 4-state clock model. Studies are carried out for several combinations of the ordering of the Curie temperatures of the austenite and martensite phases and, the martensite transformation temperature. We find that the orientation of the magnetic order which generally points along the short axis of the rectangular variant, changes as one crosses the twin or the martensite-austenite interface. The model shows the possibility of a subtle interplay between the growth of strain and magnetic order parameters as the temperature is decreased. In some cases, this leads to qualitatively different magnetization curves from those predicted by earlier mean field models. Further, we find that strain morphology can be substantially altered by the magnetic order. We have also studied the dynamic hysteresis behavior. The corresponding dissipation during the forward and reverse cycles has features similar to the Barkhausen's noise.Comment: 9 pages, 11 figure

    Homogenization in magnetic-shape-memory polymer composites

    Full text link
    Magnetic-shape-memory materials (e.g. specific NiMnGa alloys) react with a large change of shape to the presence of an external magnetic field. As an alternative for the difficult to manifacture single crystal of these alloys we study composite materials in which small magnetic-shape-memory particles are embedded in a polymer matrix. The macroscopic properties of the composite depend strongly on the geometry of the microstructure and on the characteristics of the particles and the polymer. We present a variational model based on micromagnetism and elasticity, and derive via homogenization an effective macroscopic model under the assumption that the microstructure is periodic. We then study numerically the resulting cell problem, and discuss the effect of the microstructure on the macroscopic material behavior. Our results may be used to optimize the shape of the particles and the microstructure.Comment: 17 pages, 4 figure

    First-principles study of lattice instabilities in the ferromagnetic martensite Ni2_2MnGa

    Full text link
    The phonon dispersion relations and elastic constants for ferromagnetic Ni2_2MnGa in the cubic and tetragonally distorted Heusler structures are computed using density-functional and density-functional perturbation theory within the spin-polarized generalized-gradient approximation. For 0.9<c/a<1.060.9<c/a<1.06, the TA2_2 tranverse acoustic branch along [110][110] and symmetry-related directions displays a dynamical instability at a wavevector that depends on c/ac/a. Through examination of the Fermi-surface nesting and electron-phonon coupling, this is identified as a Kohn anomaly. In the parent cubic phase the computed tetragonal shear elastic constant, C^\prime=(C11_{11}-C12_{12})/2, is close to zero, indicating a marginal elastic instability towards a uniform tetragonal distortion. We conclude that the cubic Heusler structure is unstable against a family of energy-lowering distortions produced by the coupling between a uniform tetragonal distortion and the corresponding [110][110] modulation. The computed relation between the c/ac/a ratio and the modulation wavevector is in excellent agreement with structural data on the premartensitic (c/ac/a = 1) and martensitic (c/ac/a = 0.94) phases of Ni2_2MnGa.Comment: submitted to Phys. Rev.

    XRD Characterization of the Structure of Graphites and Carbon Materials Obtained by the Low-Temperature Graphitization of Coal Tar Pitch

    Get PDF
    The structure of some commercial graphites and carbon materials (CMs) obtained by the low-temperature catalytic graphitization of coal tar pitch with iron salt, needle coke, foamed graphite as the catalysts has been studied. The study was performed using the X-ray diffraction technique with reflections from base plane and their decomposition into two components corresponding to the structural phases of graphite which have different XRD characteristics. Various CMs were compared with respect to the structural phase ratio, distance between polyarene layers in these phases, and sizes of the coherent scattering regions. The (004) reflection provided a better fit of some properties of graphites to the calculated XRD characteristics as compared to calculation from the (002) reflection. In the case of carbonization of coal tar pitch with investigated catalyst additions, prepared carbon materials have a higher degree of graphitization and a crystallite size greater than in the other case of carbonization of the individual pitch. The highest catalytic activity is shown by foamed graphite. It was found that the use of foamed graphite as the catalyst at 800-900 ºC produced carbon materials possessing a crystalline structure with interplanar spacing close to that in commercial graphites, while in the absence of catalyst the coal tar pitch material has an amorphous structure

    Genetics of CM-proteins (A-hordeins) in barley

    Full text link
    The CM-proteins, which are the main components of the A-hordeins, include four previously described proteins (CMa-1, CMb-1, CMc-1, CMd-1), plus a new one, CMe-1, which has been tentatively included in this group on the basis of its solubility properties and electrophoretic mobility. The variability of the five proteins has been investigated among 38 Hordeum vulgare cultivars and 17 H. spontaneum accessions. Proteins CMa-1, CMc-1 and CMd-1 were invariant within the cultivated species; CMd was also invariant in the wild one. The inheritance of variants CMb-1/CMb-2 and CMe-1/CMe-2,2 was studied in a cross H. spontaneum x H. vulgare. The first two proteins were inherited as codominantly expressed allelic variations of a single mendelian gene. Components CMe-2,2 were jointly inherited and codominantly expressed with respect to CMe-1. Gene CMb and gene(s) CMe were found to be unlinked. The chromosomal locations of genes encoding CM-proteins were investigated using wheat-barley addition lines. Genes CMa and CMc were associated with chromosome 1, and genes CMb and CMd with chromosome 4. These gene locations further support the proposed homoeology of chromosomes 1 and 4 of barley with chromosomes groups 7 and 4 of wheat, respectively. Gene(s) CMe has been assigned to chromosome 3 of barley. The accumulation of protein CMe-1 is totally blocked in the high lysine mutant Riso 1508 and partially so in the high lysine barley Hiproly

    Stress-induced a/b compound twins redistribution in 10M Ni-Mn-Ga martensite

    No full text
    [eng] Slight orthorhombic and monoclinic distortion of approximately tetragonal lattice in five-layered modulated (10M) martensite of Ni-Mn-Ga leads to the formation of laminates consisting of a/b compound twins. Here, we present the first direct optical observation and x-ray diffraction confirmation of the stress-induced redistribution of a/b twins of ~1-15 μm in size. We demonstrate that a/b twins are highly mobile, exhibiting twinning stress as low as 0.1 MPa, which is comparable to the twinning stress of Type 2 a/c twin boundaries. We assume that a local rearrangement of the a/b laminate may occur during the motion of a/c twin boundaries
    corecore