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Topic Review
Thermal Conductivity Improvement of PCCs
To overcome the long-standing disadvantages of PCMs, for instance, small values of thermal conductivity, liquid leakage, separation of phase, and the problem of supercooling, advanced phase change composites (PCCs) manufactured by chemical modifications or the incorporation of functional additives are essential to overcome these disadvantages and promote the large-scale application of PCMs.
  • 1.6K
  • 29 Nov 2022
Topic Review
Paramagnetic Meissner Effect (PME)
When cooling a superconductor in a magnetic field below the transition temperature, Tc, the material characteristically tries to expel the magnetic flux due to the induced shielding currents (often also called Meissner currents). When measuring the magnetic moment, m(T), in this situation a diamagnetic signal (m = negative) appears. This so-called Meissner-Ochsenfeld effect is one of the two hallmarks of superconductivity besides the zero resistance and represents the strongest proof if a material is a true superconductor. However, in the literature there are also superconducting materials which show an appearing paramagnetic (positive m) signal below Tc when measuring m(T) in small applied magnetic fields. This so-called Paramagnetic Meissner Effect (PME) or Wohlleben effect was first observed in bulk, Bi2Sr2CaCu2O8 high- Tc superconducting (HTSc) materials, and subsequently as big surprise also in conventional Nb superconductors. Since then, PME was found in many more metallic and HTSc materials, having various shapes (bulks, crystals, thin films), and various aspect ratios and compositions, including multilayers and doped materials.
  • 1.5K
  • 20 Jun 2023
Topic Review
Thermal Diffusivity and Mechanical Properties of Wood
A dependence of Brinell hardness and thermal diffusivity tensor components upon humidity for common pine wood is found. The results of the measurement of Brinell hardness, microhardness, Young’s modulus, and main components of thermal diffusivity tensor for three perpendicular cuts are found to be correlated. It is shown that the mechanical properties correlate better with the ratio of longitude to transversal thermal diffusivity coefficients than with the respective individual absolute values. The mechanical characteristics with the highest correlation with the abovementioned ratio are found to be the ratio of Young’s moduli in longitude and transversal directions. 
  • 1.5K
  • 17 Feb 2022
Topic Review
Direct Ultrafast Laser Processing
Direct ultrafast laser processing is nowadays considered the most flexible technique allowing to generate complex 3D optical functions in bulk glasses. The fact that the built-in optical element is embedded in the material brings several advantages in terms of prototype stability and lifetime, but equally in terms of complexity and number of possible applications, due to the 3D design. The generated optical functions, and in particular the single mode character of the light guiding element alongside the accessibility toward different spectral windows, depend on the refractive index contrast that can be achieved within the material transparency window and on the characteristic dimensions of the optical modification. In particular, the accessibility to the infrared and mid-infrared spectral domains, and to the relevant applications in sensing and imaging, requires increasing the cross-section of the guiding element in order to obtain the desired normalized frequency. Moreover, efficient signal extraction from the transported light requires nanometer size void-like index structures. All this demands a thorough knowledge and an optimal control of the material response within the interaction with the ultrafast laser pulse.
  • 1.4K
  • 25 Jun 2021
Topic Review
Nanocrystalline Magnetic Semiconductors for Spintronics
Сhallenge for spintronics is to find new ways for the control of electronic phenomena and magnetic properties of solids at nanoscale. Some promising aspects are connected with developing new materials. The research highlights the areas devoted to the creation of new functional materials for spintronics based on magnetic semiconductors and demonstrates the technical possibilities of creating various devices, in particular, a maser, a p-n junction with a colossal magnetoresistance, a spin valve, a magnetic lens, modulators, spin wave amplifier, etc. A magnetic semiconductor is a magnetic material that, in terms of specific conductivity, occupies an intermediate position between a conductor and an insulator, and has a band gap comparable to ~kBT. Most known magnetic semiconductors (SC) are either oxides or chalcogenides (sulfides, selenides and tellurides) of 3d transition metals, rare earth 4f metals or a combination. Spintronics (spin electronics) studies spin current transfer (spin-polarized transport) in condensed media, including contact structures, heterostructures, superlattices and multilayers. Much attention is paid to the mechano-physical methods of obtaining of high-density transparent nanoceramics based on magnetic semiconductors. The potential possibility of using nanoceramics as an absorber of solar energy, as well as in modulators of electromagnetic radiation, is also presented. The THz magneto-optics in magnetic semiconductors is shown to be beneficial to the intensively developing fields of spintronics – ultrafast magnetooptics and magnetophotonics in magnetic semiconductors.
  • 1.4K
  • 20 Dec 2022
Topic Review
Types of Liquid Crystals
The liquid-crystalline state of matter (mesomorphic state, or mesophase) is intermediate between the crystalline and liquid states, simultaneously showing some of the anisotropic properties of solids and the fluidity of liquids. In this state, materials demonstrate a tendency to flow like liquids and have some properties similar to solids. LCs may be divided into two main classes, named thermotropics and lyotropics. The importance of liquid crystals, alongside with their technical applications, lies in their role as carriers of life. In fact, fully ordered solids are a dead matter, and fully disordered liquids are also dead. But liquid crystals, as partially ordered soft matter systems, bear all qualities that had been necessary for the emergence of life. Practically all biological structures show some features pf liquid crystalline ordering. 
  • 1.4K
  • 15 Jun 2023
Topic Review
Quantification of 5f Delocalization
By using M4,5 X-ray Emission Spectroscopy (XES) in the tender X-ray regime, it is possible to quantify 5f delocalization in the actinides. Previous analyses, utilizing the Branching Ratio (BR) in the N4,5 X-ray Absorption Spectroscopy (XAS), could not discriminate between the cases of localized n = 2 and delocalized n = 3, in uranium materials, where n is the number of 5f electrons on the U entity. Here, it is shown that, by employing the ubiquitous 6p→3d XES as a point of normalization, the localized n = 2 and delocalized n = 3 cases can be easily distinguished and quantified.
  • 1.4K
  • 29 Oct 2020
Topic Review
Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy
The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. 
  • 1.3K
  • 26 Jan 2022
Topic Review
Topological and Dissipative Solitons in Liquid Crystals
Solitons are self-sustained localized packets of waves in nonlinear media that propagate without changing shape. They are found everywhere in our daily life from nerve pluses in our bodies to eyes of storms in the atmosphere and even density waves in galaxies. Solitons in liquid crystals have received increasing attention due to their importance in fundamental physical science and potential applications in various fields. 
  • 1.3K
  • 21 Jan 2022
Topic Review
Superconductivity and Hydrogen Economy
Hydrogen as an energy carrier is a promising alternative to fossil fuels, and it becomes more and more popular in developed countries as a carbon-free fuel. The low boiling temperature of hydrogen (20 K or −253.15 °C) provides a unique opportunity to implement superconductors with a critical temperature above 20 K such as MgB2 or high-temperature superconductors. Superconductors increase efficiency and reduce the loss of energy, which could compensate for the high price of LH2 to some extent. Norway is one of the pioneer countries with adequate infrastructure for using liquid hydrogen in the industry, especially in marine technology where a superconducting propulsion system can make a remarkable impact on its economy. Using superconductors in the motor of a propulsion system can increase its efficiency from 95% to 98% when the motor operates at full power. The difference in efficiency is even greater when the motor does not work at full power.
  • 1.3K
  • 19 Oct 2022
Topic Review
Ramchandra Pode
I am involved in the field of organic light emitting devices since 2002. I also worked as visiting Scientist at Korea Electronics Technology Institute, South Korea in 2003 and 2005 (Brain Pool, KOFST) on OLEDs devices. I am specialized in Organic Light Emitting Diode (OLEDs) devices and displays and acquired enough expertize to conduct the research project on OLEDs. During these years, I have published around 65 research articles in various SCI journals of repute. In addition, I have contributed chapters to two books on OLEDs.
  • 1.3K
  • 28 Oct 2020
Topic Review
Langmuir–Blodgett Graphene-Based Films
The prevalence of photosynthesis, as the major natural solar energy transduction mechanism or biophotovoltaics (BPV), has always intrigued mankind. The development of high performance and durable BPVs is dependent on upgraded anode materials with electrochemically dynamic nanostructures. However, the current challenges in the optimization of anode materials remain significant barriers towards the development of commercially viable technology. Langmuir–Blodgett (LB) film has been substantiated as an efficacious film-forming technique to tackle the above limitations of algal BPVs; however, the aforesaid technology remains vastly untapped in BPVs.
  • 1.3K
  • 08 Mar 2022
Topic Review
Sea Urchin-like Si@MnO2@rGO
An unique structure which can effectively reduce the volume change of Si, extend the cycle life and increase the lithium-ion battery capacity.
  • 1.3K
  • 24 Feb 2022
Topic Review
Magnetic Properties and Magnetocaloric Effect of Pr2Co7 Compound
The Pr2Co7 compound has interesting magnetic properties, such as a high Curie temperature TC and uniaxial magnetocrystalline anisotropy. It crystallizes in a hexagonal structure (2:7 H) of the Ce2Ni7 type and is stable at relatively low temperatures (Ta ≤ 1023 K), or it has a rhombohedral structure (2:7 R) of the Gd2Co7 type and is stable at high temperatures (Ta ≥ 1223 K). Studies of the magnetocaloric properties of the nanocrystalline Pr2Co7 compound have shown the existence of a large reversible magnetic entropy change (ΔSM) with a second-order magnetic transition. 
  • 1.2K
  • 15 Jun 2023
Topic Review
Exchange Bias in Nanostructures
Exchange bias (EB) is a unidirectional anisotropy occurring in exchange-coupled ferromagnetic/antiferromagnetic systems, such as thin films, core–shell particles, or nanostructures. In addition to a horizontal shift of the hysteresis loop, defining the exchange bias, asymmetric loops and even vertical shifts can often be found. 
  • 1.2K
  • 30 Aug 2023
Topic Review
Bulk and Single Crystal Growth Progress of FBS
The new iron-based superconductor (FBS) has generated enormous interest in this direction, and many research activities are currently going on with various kinds of FBS. FBS was discovered in 2008 through F doped LaFeAsO, which crystallizes with a tetragonal layered ZrCuSiAs structure, and after that, many compounds have been discovered, most of which display superconductivity through suitable doping. FBS became the second high-Tc-superconducting family after cuprate superconductors and has been the subject of extensive research into their physical nature and application potential.
  • 1.1K
  • 14 Jan 2022
Topic Review
Soft Templates for Fabricating 3D Nanostructures
Just like rigid templates, there are numerous types of soft templates, including electron resist polymer, photoresist polymer, and various assembled polymers consisting of block polymer, fiber or membrane, polystyrene (PS) sphere, and so forth. These versatile soft templates can be used in the ALA method and have broad prospects for development in powerful fabrication of multiple nanostructures, which possess a lot of advantages, such as simple process, good flexibility, repeatable simplicity of the process, and environmentally friendly easy elimination of the templates, resulting in diversiform 3D nanostructures with numerous device applications.
  • 1.1K
  • 21 Jun 2022
Topic Review
Solid and Liquid Oxygen under Ultrahigh Magnetic Fields
Oxygen is a unique molecule that possesses a spin quantum number S=1. In the condensed phases of oxygen, the delicate balance between the antiferromagnetic interaction and van der Waals force results in the various phases with different crystal structures. By applying ultrahigh magnetic fields, the antiferromagnetic coupling between O2 molecules breaks, and novel high-field phase (θ phase) appears. Since oxygen is an important element for various (bio-)chemical reactions, the reorientation of O2 molecules could be an attractive mechanism for contrlling the reactivity.
  • 1.1K
  • 01 Aug 2022
Topic Review
Low-energy electron Damage to DNA
The complex physical and chemical reactions between the large number of low-energy (0-30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as single strand breaks (SSBs), crosslinks (CLs), base modifications, double strand breaks (DSBs) and other clustered lesions.
  • 1.0K
  • 29 Jul 2021
Topic Review
The Phase Field Approach
The phase field approach was developed in the last 20 years to handle radiation damage in materials. This approach bridges the gap between atomistic simulations extensively used to model first step of radiation damage at short time and continuum approach at large time. The main advantage of such an approach lies in its ability to compute not only the microstructure at the nanometric scale but also to calculate generalized susceptibilities such as elastic constants under irradiation.
  • 995
  • 05 May 2022
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