an irreversible stirling heat pump cycle using ferromagnetic materials as a cyclic working substance is established. the influences of finite-rate heat transfer, heat leak, regeneration time, regenerative lossand the internal irreversibility on the cyclic performance of magnetic heat pumps are taken into account. on the basis of the thermodynamic properties of ferromagnetic materials, the perfo...

We describe here a simple synthetic strategy for the fabrication of carbon-coated Fe3O4 (Fe3O4@C) particles using a single-component precursor, iron (III) diethylenetriaminepentaacetic acid complex. Physicochemical analyses revealed that the core of the synthesized particles consists of ferromagnetic Fe3O4 material ranging several hundred nanometers, embedded in nitrogen-doped graphitic carbon ...

We report a new kind of field-responsive fluid consisting of suspensions of diamagnetic (DM) and ferromagnetic (FM) microparticles in ferrofluids. We designate them as inverse magnetorheological (IMR) fluids for analogy with inverse ferrofluids (IFFs). Observations on the particle self-assembly in IMR fluids upon magnetic field application showed that DM and FM microparticles were assembled int...

We consider temperature-driven phase transitions occurring in a liquid crystal suspension of ferromagnetic particles within the Landau–de Gennes theory. The temperature dependences order parameters uniaxial model with vector parameter for magnetic subsystem are obtained. dimensionless expression free energy density has been used study behavior general regularities system. Phase state diagrams a...

In this paper, using high order perturbative series expansion method, the critical exponents of the order parameter and susceptibility in transition from ferromagnetic to disordered phases for 1D quantum Ising model in transverse field, with ferromagnetic nearest neighbor and anti-ferromagnetic next to nearest neighbor interactions, are calculated. It is found that for small value of the frustr...

We discuss the occurrence of Bose-Einstein condensation in systems of noninteracting charged particles in three and one dimensions and in presence of an external magnetic eld. In the one dimensional, as well as in the magnetic eld cases, although not a critical temperature, a characteristic temperature can be found, corresponding to the case in which the ground state density becomes a macroscop...

In this work, we report on a novel strategy to implement and to optimize heterogeneous bioassays on an electrowetting-on-dielectric (EWOD) digital lab-on-a-chip analysis platform, namely the use of ferromagnetic particles as functional carriers for biomolecules in combination with a highly efficient extraction protocol. This extraction protocol serves as an extension to the common operations of...

The magnetic relaxation of ferromagnetic powders has been studied for many years, largely due to its importance to recording technologies. However, only recently have experiments been performed that resolve the magnetic state of individual sub-micron particles. Motivated by these experimental developments, we use droplet theory and Monte Carlo simulations to study the time and field dependence ...