Effects of 3d transition metal impurities and vacancy defects on electronic and magnetic properties of pentagonal Pd2S4: competition between exchange splitting and crystal fields.

In this paper, we first investigate the electronic properties of the two-dimensional structure of dichalcogenide Pd2S4. These properties strongly depend on the crystal field splitting which can change by atomic vacancies (S and Pd vacancies). The main purpose of the present paper is to create remarkable magnetic properties in the system by adding 3d transition metal atoms where the presence of Mn, Cr, and Fe creates the exchange interaction in the system as well as change in the crystal field. The created magnetic properties strongly depend on the competition between exchange interaction and crystal field to separate the levels of d orbitals. In addition, the presence of the transition metals in the structures with S and Pd vacancy has been investigated carefully. The calculations demonstrate that we can achieve an extensive range of magnetic moment up to 3.131 [Formula: see text]. The maximum one is obtained in the presence of Mn and absence of sulfur while some of the doped structures does not have magnetic moment. Our results show that Pd vacancy in the presence of Cr, Mn and Fe metals increases the magnetic property of the Pd2S4 structure. The extensiveness and variety of the obtained properties can be used for different magnetic and non-magnetic applications.

Band structure engineering of NiS2 monolayer by transition metal doping.

By using density functional theory calculations, we have studied the effects of V-, Cr-, Mn-, Fe- and Co-doped on the electronic and magnetic properties of the 1T-NiS2 monolayer. The results show that pure 1T-NiS2 monolayer is a non-magnetic semiconductor. Whereas depending on the species of transition metal atom, the substituted 1T-NiS2 monolayer can become a magnetic semiconductor (Mn-doped), half-metal (V- and Fe-doped) and magnetic (Cr-doped) or non-magnetic (Co-doped) metal. The results indicate that the magnetism can be controlled by the doping of 3d transition metal atoms on the monolayer. In this paper, the engineering of the electric and magnetic properties of 1T-NiS2 monolayer is revealed. It is clear that it could have a promising application in new nanoelectronic and spintronic devices.

The impact of Fe atom on the spin-filter and spin thermoelectric properties of Au-Fe@C20-Au monomer and dimer systems.

Based on density functional theory and non-equilibrium Green's function formalism, we explore the effect of Fe atom in Au-Fe@C20-Au monomer and dimer systems in comparison with the C20 fullerene molecular junctions. We calculate the spin-dependent transmission coefficient, spin polarization and also their spin thermoelectric coefficients to investigate magnetic properties in the system. Our results indicate that the presence of Fe atoms enhances substantially the spin-filter and increases the spin figure of merit in the dimer system. We suggest that the Au-(Fe@C20)2-Au system is a suitable junction for designing spin-filtering and spin thermoelectric devices and eventually it is a good candidate for spintronic applications.

Inclusion of graphene on LDPE properties.

The spread of graphene in low-density polyethylene (LDPE) improves LDPE/graphene nanocompounds' thermal/mechanical/electrical characteristics. The images of scanning electron microscopy (SEM) verify full graphene exfoliation at 1000 °C. Inclusion graphene develops crystallinity; increases the local order of lattice and thermal stability of LDPE/graphene nanocompounds. The consistent distributions and further inclusion of graphene caused the great heat breakdown strength, increasing heat breakdown activation energy and a superior melting point (Tm) for LDPE nanocompounds. Percolation occurs with the graphene incorporation of 0.5 wt%. The complex viscosity test showed Newtonian behavior for LDPE at a very low frequency. But, graphene inclusion to LDPE changed the viscosity performance from liquid-like to solid-like which caused a decrease in the melt flow rate (MFR) values for all LDPE/graphene nanocompounds.

Investigation of optical bistability in a double In(x)Ga(1-x)N/GaN quantum-dot nanostructure via inter-dot tunneling effect.

In this paper, our aim is to control optical bistability (OB) and optical multistability (OM) in a five-level system designed in a double quantum dot (QD) nanostructure. In a realistic example, this atomic system is created in two semiconductor QDs (In(x)Ga(1-x)N/GaN), owning transfer of carriers via tunneling effect. OB behavior is controlled not only by the inter-dot tunneling effect but also by variation of probe detuning and intensity of the control field. It is demonstrated that voltage-controlled detuning can significantly affect the behavior of OB and OM; therefore, the OM converts to OB by probe detuning and intensity of the control field.

Phase control of light transmission and reflection based biexciton coherence in a defect dielectric medium.

Phase control of two weak probe lights' transmission and reflection based biexciton coherence in a defect dielectric medium doped by four-level GaAs/AlGaAs multiple quantum wells with 15 periods of 17.5 nm GaAs wells and 15 nm Al0.3Ga0.7As barriers is theoretically investigated. The biexciton coherence in this scheme is set up by two continuous wave control fields that couple to a resonance of biexcitons. It is shown that the transmission and reflection properties versus relative phase between applied fields can be controlled by the intensity of control fields and exciton spin relaxation between exciton states. Our studies show that many-particle interactions due to Coulomb correlations in semiconductors can be harnessed by quantum coherence in an interacting many-particle system.

Comparison between NSAID and intra-articular corticosteroid injection in frozen shoulder of diabetic patients; a randomized clinical trial.

INTRODUCTION: Frozen shoulder or adhesive capsulitis is a relatively common encountered musculo-skeletal disease in which arouses following soft tissue involvement of glenohumeral joint and presents with pain and limitation of shoulder' active and passive motions. The incidence of frozen shoulder among diabetic patients is about 10-20%, stiffness in such patients is more severe and should be managed actively. Local Glucocorticoid injection, NSAIDs and physiotherapy each can relief the symptoms. The aim of this study was to compare the efficacy of glenohumeral injection of Glucocorticoid with NSAIDs in frozen shoulder of diabetic patients. METHOD: The randomized clinical trial study conducted during Feb 2009-Aug 2010 on diabetic patients with frozen shoulder that were referred to rheumatology and endocrinology clinics, Yazd, Iran. Diagnostic criteria of capsulitis were pain of shoulder and range of motion limitation in all directions. The patients were divided into 2 groups, patients of first group received NSAID while the latter group were undergone intra-articular corticosteroid injection. After 1 week, home exercise was done for both group and evaluation of the patients after first visit was done likewise 2nd, 6th, 12th and 24th weeks. All registered data were transformed into SPSS-15 software and analyzed. RESULTS: Totally 57 patients (19 males (33.3%) and 38 females (66.7%) were included in the analysis. There was no significant difference between sex (P=0.4) and age (P=0.19) of patients. No significant relation was detected between 2 groups after 24 weeks according to range of motion in flexion (P=0.51), abduction (P=0.76), external rotation (0.12) and internal rotation (P=0.91). Also any significant difference in pain score was not detected (P=0.91). CONCLUSION: Based on our study, both intra-articular corticosteroid and NSAID are effective in treatment of adhesive capsulitis and there is no significant difference between efficacies of these 2 treatment modalities in diabetic patients.

Reducing interpolation artifacts for mutual information based image registration.

Medical image registration methods which use mutual information as similarity measure have been improved in recent decades. Mutual Information is a basic concept of Information theory which indicates the dependency of two random variables (or two images). In order to evaluate the mutual information of two images their joint probability distribution is required. Several interpolation methods, such as Partial Volume (PV) and bilinear, are used to estimate joint probability distribution. Both of these two methods yield some artifacts on mutual information function. Partial Volume-Hanning window (PVH) and Generalized Partial Volume (GPV) methods are introduced to remove such artifacts. In this paper we show that the acceptable performance of these methods is not due to their kernel function. It's because of the number of pixels which incorporate in interpolation. Since using more pixels requires more complex and time consuming interpolation process, we propose a new interpolation method which uses only four pixels (the same as PV and bilinear interpolations) and removes most of the artifacts. Experimental results of the registration of Computed Tomography (CT) images show superiority of the proposed scheme.