Orthopaedic biomaterials play a pivotal role in advancing fracture fixation, joint replacement, and dynamic stabilization within orthopaedic applications. Primarily composed of metals, these biomaterials exhibit outstanding properties including high strength, ductility, fracture toughness, hardness, corrosion resistance, durability, and biocompatibility. Despite their versatility, the landscape of orthopaedic implant materials remains dominated by a limited range of metals, ceramics, composites and polymers. However, the durability of these implants is challenged by biological reactions and material degradation caused by wear and electrochemical corrosion. This article examines the developments that have taken place with respect to the biomaterials and their applications in implants in orthopaedic surgery. This encompasses history, types and properties of metals, polymers, ceramics, composite biomaterials, and processes of fabricating them. The characteristics like biocompatibility, mechanical properties, fluid stability, and the ability to induce osseointegration and the relevance of such materials for implants in orthopaedic surgery is also discussed in this article. Special attention is given to the development of novel bioactive metallic materials and their means of improving wear resistance and biocompatibility by changing the surface and applying coats. The scope of the review further covers advanced technologies including smart bio-materials, 3D/4D printing, use of nanotechnology, and prosthetics. Further, the review article discusses the current status and future trends concerning materials for orthopaedic surgery in greater detail.
Rabia Sultana, Ganesh Gurjar, Bhasker Gahtori
et al.
Here, we report the crystal growth, physical and transport properties of Bi1-xSbx (x = 0.05, 0.1 and 0.15) topological insulator. Single crystals of Bi1-xSbx (x = 0.05, 0.1 and 0.15) were grown by melting bismuth and antimony together using the facile self flux method. The XRD measurements displayed highly indexed 00l lines and confirmed the crystalline nature as well as the rhombohedral structure of the Bi1-xSbx (x = 0.05, 0.1 and 0.15) crystals. Raman spectroscopy measurements for Bi1-xSbx system revealed four peaks within the spectral range of 10 to 250 cm-1 namely A1g and Eg modes corresponding to Bi-Bi and Sb-Sb vibrations. Scanning electron microscopy (SEM) and energy dispersive Temperature dependent electrical resistivity curves with and without applied magnetic field exhibited a metallic behaviour and linear non-saturating magneto-resistance (MR) respectively for all the antimony (Sb) concentrations of x = 0.05, 0.1 and 0.15. The lowest Sb concentration sample with x = 0.05 (Bi0.95Sb0.05) exhibited the highest MR value of about 1400%, followed by x = 0.1 and 0.15 samples (Bi0.9Sb0.1 and Bi0.85Sb0.05) with MR values reaching up to 500% and 110% respectively at 2K and 6Tesla applied field. The magneto-conductivity (MC) is fitted to the HLN (Hikami Larkin Nagaoka) equation and it is found that the charge conduction mechanism is mainly dominated by WAL (weak anti-localization) along with a small contribution from WL (weak localization) effect. Summarily, the short letter discusses the synthesis, interesting transport and magneto-transport properties of Bi1-xSbx (x = 0.05, 0.1 and 0.15), which could be useful in understanding the fascinating properties of topological insulators and their technological applications.
This paper has been updated by the author to: arXiv:1012.0060v1 [cond-mat.mes-hall], titled "Collective Nuclear Stabilization by Optically Excited Hole in Quantum Dot"
Massimo Campostrini, Martin Hasenbusch, Andrea Pelissetto
et al.
We present the high-temperature series for a nearest-neighbor model with O(2) symmetry on a simple cubic lattice with the most general single-site potential. In particular, the magnetic susceptibility and the second-moment correlation length are computed to 22nd order. The series specialized to some particular improved Hamiltonians have been already analyzed in the paper M. Campostrini, M. Hasenbusch, A. Pelissetto, and E. Vicari, Phys. Rev. B 74, 144506 (2006) [cond-mat/0605083], to determine the critical exponents and other universal quantities of the three-dimensional XY universality class.
Uniform-field effects for frustrated odd-leg integer-spin tubes (cylinder type spin systems) are investigated in the weak interchain-coupling regime. We predict that, as the field exceeds the spin gap, a two-component Tomonaga-Luttinger liquid (TLL) appears due to the condensation of the doubly degenerate lowest magnons. Furthermore, it is argued that when the uniform field is so strong that the second lowest magnons are also condensed, the two-component TLL is destroyed and a new one-component TLL emerges. This quantum phase transition may be detected as a magnetization cusp.
In my thesis I study mesoscopic corrections on diffuse transport. I first describe the diffuse transport of light, using the scalar approximation and the radiative transfer approach. Next, I focus on the correlations in transmission, I discuss the so called C_1, C_2, C_3 decomposition and calculate each term in detail. Finally, I discuss the full distribution functions in the transmission. Many references and figures are included. Note, however, that much of the work was already published or is present on the cond-mat archive. A limited number is available as hardcopy on request (vrossum@phys.uva.nl) else 132 pages Postscript.
We revisit the issues on the thermodynamic property of stellar self-gravitating system arising from Tsallis' non-extensive entropy. Previous papers (Taruya & Sakagami, Physica A 307 (2002) 185 (cond-mat/0107494); ibid. (2002) in press (cond-mat/0204315)) have revealed that the extremum-state of Tsallis entropy characterized by the so-called stellar polytrope has consistent thermodynamic structure, which predicts the thermodynamic instability due to the negative specific heat. However, their analyses heavily relies on the old Tsallis formalism using standard linear mean values. In this paper, extending our previous study, we focus on the equilibrium structure based on the standard framework by means of the normalized q-expectation values. It then turns out that the new extremum-state of Tsallis entropy essentially remains unchanged from the previous result, i.e., the stellar quasi-equilibrium distribution can be described by the stellar polytrope. While the thermodynamic stability for a system confined in an adiabatic wall completely agrees with the previous study and thereby the stability/instability criterion remains unchanged, the stability analysis reveals a new equilibrium property for the system surrounded by a thermal bath. In any case, the stability/instability criteria are consistently explained from the presence of negative specific heat and within the formalism, the stellar polytrope is characterized as a plausible non-extensive meta-equilibrium state.
In cond-mat/0103603 Diffusion algebras have been introduced in the context of one-dimensional stochastic processes with exclusion in statistical mechanics. While this reference is focused on the needs of the physicist reader and thus states results without proofs and focuses on the discussion of lower-dimensional examples, it is the purpose of this paper to present a construction formalism for Diffusion algebras and to use the latter to prove the results in that reference.
Using field-theoretic methods, we calculate the internal energy for the One-Component Plasma (OCP). We go beyond the recent calculation by Brilliantov [N. Brilliantov, Contrib. Plasma Phys. 38, pg. 489 (1998) / cond-mat/9805358] by including non-Gaussian terms. We show that, for the whole range of the plasma parameter Gamma, the effect of the higher-order terms is small and that the final result is not improved relative to the Gaussian theory when compared to simulations.
The response of a coupled array of nonlinear oscillators to parametric excitation is calculated in the weak nonlinear limit using secular perturbation theory. Exact results for small arrays of oscillators are used to guide the analysis of the numerical integration of the model equations of motion for large arrays. The results provide a qualitative explanation for a recent experiment [Buks and Roukes, cond-mat/0008211, to appear in J. MEMS (2002)] involving a parametrically-excited micromechanical resonator array. Future experiments are suggested that could provide quantitative tests of the theoretical predictions.
Using the supersymmetry technique, we analytically derive the recent result of Casati, Maspero and Shepelyansky [cond-mat/9706103] according to which the quantum dynamics of open chaotic systems follows the classical decay up to a new quantum relaxation time scale $t_q\sim\sqrt{t_c t_H}$. This scale is larger than the classical escape time $t_c$ but still much smaller than the Heisenberg time $t_H$. For systems with orthogonal or unitary symmetry the quantum decay is slower than the classical one while for the symplectic case there is an intermediate regime in which the quantum decay is slightly faster.
We have grown spiral carbon nanofibers containing Pd metal clusters using the Pd2(dba)3 catalyzed decomposition of gaseous acetylene on molecular sieves (AlPO4-5) support. The microstructure and composition of the spiral carbon nanofibers were examined by the powder x-ray diffractometer and transmission electron microscope. The conductivity of the mat in the temperature range from 14 to 250 K could be described by the form of exp[-(T-1/4)]. The thermopower shows a remarkably linear behavior down to 40 K, reminiscent of some conducting polymers. The sign change of the thermopower suggests there exists more than one type of charge carrier, which could be ascribed to the different types of nanotube with various sizes of radius. The transport behavior of spiral carbon nanofibers containing Pd metal clusters will be discussed in the framework of the heterogeneous model.
Two chains of ultrasmall Josephson junctions, coupled capacitively with each other in the two different ways, straight and slanted coupling, are considered. As the coupling capacitance increases, regardless of the coupling scheme, the transport of particle-hole pairs in the system is found to drive the quantum-phase transition at zero temperature, which is a insulator-to-superfluid transition of the particle-hole pairs and belongs to the Berezinskii-Kosterlitz-Thouless universal class. The different underlying transport mechanisms for the two coupling schemes are reflected in the difference between the transition points.
We study tunneling currents in a model consisting of two non-unitary ferromagnetic spin-triplet superconductors separated by a thin insulating layer. We find a novel interplay between ferromagnetism and superconductivity, manifested in the Josephson effect. This offers the possibility of tuning dissipationless currents of charge and spin in a well-defined manner by adjusting the magnetization direction on either side of the junction.
We consider the influence of magnetic excitations on the local density of states in the d-wave superconductor. The magnetic susceptibility is calculated within the renormalized $t-t'-J$ model and its influence on the quasiparticle self-energy is considered using a minimal model originally proposed by Polkovnikov {\it et al.}[cond-mat/0203176]. We find the local density of states possess periodic components both along $(π,0)$ and $(π,π)$ directions with the associated wavevectors changing in magnitude as the quasiparticle energy is varied. Comparison with the STM experiment reveals that the calculated LDOS modulation is inconsistent with the measured data.
We use the Renormalization Group method to study the Bose-Einstein condensation of the interacting dilute magnons which appears in three dimensional spin systems in magnetic field. The obtained temperature dependence of the critical field $H_c(T)-H_c(0) \sim T^{2}$ is different from the recent self-consistent Hartree-Fock-Popov calculations (cond-mat/0405422) in which a $T^{3/2}$ dependence was reported . The origin of this difference is discussed in the framework of quantum critical phenomena.
In a recent Physics Review Letter, Dorlas and Wedagedera have studied the random energy model with an additional p-spin ferromagnetic interaction. Here we note that (i) we have solved the corresponding problem of a spherical spin system with p-spin glass interactions and r-spin ferromagnetic interactions, and (ii) a simple mapping yields the results of DW and generalizations. Reference: http://arXiv.org/abs/cond-mat/9912201
We respond to criticisms raised by K. Varga (cond-mat/9802262) and reaffirm that the results in our original paper obtained using a two-body analytical method remains valid within the framework of an effective excitonic composite model. The conceptual model of the excitonic systems as well as the numerical method based on variational functions utilized by Varga differ significantly from ours. Hence comparison of binding energies of the charged-biexciton remains questionable. In this reply, we discuss the shortcomings of modelling the charged-biexciton as a five-body system and treating excitonic complexes as atomic systems, as done in Varga's Comment.
Motivated by recent experiments involving the non-destructive imaging of magnetization of a spin-1 87Rb Bose gas (Higbie et al., cond-mat/0502517), we address the question of how the spontaneous magnetization of a ferromagnetic BEC occurs in a spin-conserving system. Due to competition between the ferromagnetic interaction and the total spin conservation, various spin structures such as staggered magnetic domains, and helical and concentric ring structures are formed, depending on the geometry of the trapping potential.
We have verified that the variational mean field theory approach suggested by Narimanov and Varma (preprint cond-mat/0002191) being applied to the realistic two-band model provides a good agreement with experimental data for the Curie temperature in doped manganites A$_{1-x}$B$_x$MnO$_3$ ($x\simeq{0.3}$). We have also considered the problem of an interplay between the ferromagnetic and antiferromagnetic interactions by using the same approach.