Magnetocrystalline anisotropic effect in GdCo1−x_{1-x}Fex_xAsO (x=0,0.05x = 0, 0.05)

From a systematic study of the electrical resistivity $\rho(T,H)$, magnetic susceptibility $\chi(T,H)$, isothermal magnetization $M(H)$ and the specific heat $C(T,H)$, a temperature-magnetic field ($T$-$H$) phase diagram has been established for GdCo$_{1-x}$Fe$_x$AsO ($x = 0$ and $0.05$) polycrystalline compounds. GdCoAsO undergoes two long-range magnetic transitions: ferromagnetic (FM) transition of Co $3d$ electrons ($T_\textup{C}^\textup{Co}$) and antiferromagnetic (AFM) transition of Gd $4f$ electrons ($T_\textup{N}^\textup{Gd}$). For the Fe-doped sample ($x=0.05$), an extra magnetic reorientation transition takes place below $T_\textup{N}^\textup{Gd}$, which is likely associated with Co moments. The two magnetic species of Gd and Co are coupled antiferromagnetically to give rise to ferrimagnetic (FIM) behavior in the magnetic susceptibility. Upon decreasing the temperature ($T < T_\textup{C}^\textup{Co}$), the magnetocrystalline anisotropy breaks up the FM order of Co by aligning the moments with the local easy axes of the various grains, leading to a spin reorientation transition at $T_\textup{R}^\textup{Co}$. By applying a magnetic field, $T_\textup{R}^\textup{Co}$ monotonically decreases to lower temperatures, while the $T_\textup{N}^\textup{Gd}$ is relatively robust against the external field. On the other hand, the applied magnetic field pulls the magnetization of grains from the local easy direction to the field direction via a first-order reorientation transition, with the transition field ($H_\textup{M}$) increasing upon cooling the temperature.Comment: accepted by physical Review B 6 figures and 7 page

Observation of inhibited spontaneous emission and stimulated emission of rhodamine 6G in polymer replica of synthetic opal

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in K. Yoshino, S. B. Lee,b) S. Tatsuhara, Y. Kawagishi, and M. Ozaki, and A. A. Zakhidov, Appl. Phys. Lett. 73, 3506 (1998) and may be found at https://doi.org/10.1063/1.122819

Nonlocal electrodynamics of two-dimensional wire mesh photonic crystals

We calculate analytically the spectra of plasma waves and electromagnetic waves (EMW) in metallic photonic crystal consisting of the parallel thin infinite metallic cylinders embedded in the dielectric media. The axes of metallic cylinders form a regular square lattice in a plane perpendicular to them. The metal inside the cylinders is assumed to be in the high frequency regime $\omega \tau >> 1$, where $\tau$ is the relaxation time. The proposed analytical theory is based upon small parameters $f << 1$, where $f$ is the volume fraction of the metal, and $kR << 1$, where $k$ is the wave vector and $R$ is the radius of the cylinder. It is shown that there are five different branches of the EMW that cover all frequency range under consideration except one very small omnidirectional gap in the vicinity of the frequency of the surface plasmon. However, at some directions of propagation and polarizations the gap may be much larger. The reflection and refraction of the EMW is also considered. The general theory of refraction is proposed which is complicated by the spatial dispersion of the dielectric constant, and one particular geometry of the incident EMW is considered.Comment: 14 pages, 8 figure

Braggoriton--Excitation in Photonic Crystal Infiltrated with Polarizable Medium

Light propagation in a photonic crystal infiltrated with polarizable molecules is considered. We demonstrate that the interplay between the spatial dispersion caused by Bragg diffraction and polaritonic frequency dispersion gives rise to novel propagating excitations, or braggoritons, with intragap frequencies. We derive the braggoriton dispersion relation and show that it is governed by two parameters, namely, the strength of light-matter interaction and detuning between the Bragg frequency and that of the infiltrated molecules. We also study defect-induced states when the photonic band gap is divided into two subgaps by the braggoritonic branches and find that each defect creates two intragap localized states inside each subgap.Comment: LaTeX, 8 pages, 5 figure

Silver nanowires on carbon nanotube aerogel sheets for flexible, transparent electrodes

Flexible, free-standing transparent conducting electrodes (TCEs) with simultaneously tunable transmittances up to 98% and sheet resistances down to 11 Ω/sq were prepared by a facile spray-coating method of silver nanowires (AgNWs) onto dry-spun multiwall carbon nanotube (MWNT) aerogels. Counterintuitively, the transmittance of the hybrid electrodes can be increased as the mass density of AgNWs within the MWNT aerogels increases, however, the final achievable transmittance depends on the initial transparency of the MWNT aerogels. Simultaneously, a strong decrease in sheet resistance is obtained when AgNWs form a percolated network along the MWNT aerogel. Additionally, anisotropic reduction in sheet resistance and polarized transmittance of AgNW/MWNT aerogels is achieved with this method. The final AgNW/MWNT hybrid TCEs transmittance and sheet resistance can be fine-tuned by spray-coating mechanisms or by choosing initial MWNT aerogel density. Thus, a wide range of AgNW/MWNT hybrid TCEs with optimized optoelectronic properties can be achieved depending of the requirements needed. Finally, the free-standing AgNW/MWNT hybrid TCEs can be laminated onto a wide range of substrates without the need of a bonding aid

Риски хирургического лечения глаукомы на единственном видящем глазу с далекозашедшей стадией заболевания

This review summarizes the results of surgical treatment of far-advanced stage glaucoma in the only seeing eye. A literature search performed in the PubMed search engine and aimed at finding publications reporting the clinical outcomes of treatment in patients with glaucoma in the only seeing eye did yield sufficient data related to the topic. A comprehensive analysis of the available data was performed with an emphasis on the choice of treatment tactics and postoperative results at various times following a surgery. Several studies allowed to perform a comparison of the clinical advantages and cost-effectiveness of medical treatment versus surgery for advanced glaucoma, as well as to assess potential risks and adverse outcomes such as glaucoma progression, postoperative scarring, hypotension and other complications. The results presented in this review suggest that common success criteria can provide uniformity in academic studies, but in daily clinical practice each glaucoma specialist must make a patient-specific decision in favor of either of these methods of treatment in order to guarantee an optimal result, both for the doctor and, of course, for the patient.Цель обзора — обобщить результаты, полученные после проведенного хирургического лечения далекозашедшей стадии глаукомы на единственно видящем глазу. Поиск литературы, выполненный в поисковой системе PubMed и направленный на обнаружение публикаций, сообщающих о клинических результатах проведенного лечения у пациентов с глаукомой на единственно видящем глазу, не позволил нам найти достаточного объема такого рода исследований. Проведен всесторонний анализ имеющихся данных с акцентом на выбор тактики лечения и послеоперационные результаты в различные сроки после операции. Некоторые исследования позволили сравнить клиническую и экономическую эффективность медикаментозного лечения по сравнению с хирургическим лечением далекозашедшей стадии глаукомы, а также оценить вероятные риски и неблагоприятные исходы, такие как прогрессирование глаукомы, послеоперационное рубцевание, гипотонию и другие осложнения. Результаты, представленные в обзоре, позволяют сделать вывод, что общие критерии успеха могут обеспечить однородность в академических исследованиях, но в повседневной клинической практике каждый глаукоматолог должен индивидуально принимать решение в пользу того или иного метода лечения, чтобы гарантировать оптимальный результат, как для врача, так и, естественно, для пациента