Tuning thermal transport in graphene via combinations of molecular antiresonances

We propose a method to engineer the phonon thermal transport properties of low dimensional systems. The method relies on introducing a predetermined combination of molecular adsorbates, which give rise to antiresonances at frequencies specific to the molecular species. Despite their dissimilar transmission spectra, thermal resistances due to individual molecules remain almost the same for all species. On the other hand, thermal resistance due to combinations of different species are not additive and show large differences depending on the species. Using a toy model, the physics underlying the violation of resistance summation rule is investigated. It is demonstrated that equivalent resistance of two scatterers having the same resistances can be close to the sum of the constituents or $\sim$70\% of it depending on the relative positions of the antiresonances. The relative positions of the antiresonances determine the net change in transmission, therefore the equivalent resistance. Since the entire spectrum is involved in phonon spectrum changes in different parts of the spectrum become important. Performing extensive first-principles based computations, we show that these distinctive attributes of phonon transport can be useful to tailor the thermal transport through low dimensional materials, especially for thermoelectric and thermal management applications.Comment: 4 figures (1 figure and 2 videos as supplemental material

One dimensional photonic crystal waveguide

Thesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2004Includes bibliographical references (leaves: 83-84)Text in English; Abstract: Turkish and Englishxi,84 leavesThis thesis deals with the implementation of a numerical method to describe how electromagnetic waves propagate through a one-dimensional photonic crystal waveguide. The one-dimensional photonic crystal waveguide is a periodic arrangement of dielectric slabs of alternating dielectric constant with an impurity slab introduced as the guiding layer. This impurity guides, and connes light within a given range of frequencies by producing waveguide modes within the photonic band gap. These modes are different from those of conventional waveguides that use total internal reflection as the basic guiding mechanism. Photonic crystal waveguides are expected to lead to compact photonic integrated circuits

Robustness of One-Dimensional Photonic Bandgaps Under Random Variations of Geometrical Parameters

The supercell method is used to study the variation of the photonic bandgaps in one-dimensional photonic crystals under random perturbations to thicknesses of the layers. The results of both plane wave and analytical band structure and density of states calculations are presented along with the transmission cofficient as the level of randomness and the supercell size is increased. It is found that higher bandgaps disappear first as the randomness is gradually increased. The lowest bandgap is found to persist up to a randomness level of 55 percent.Comment: Submitted to Physical Review B on April 8 200

Türkiye kıyısal sularında (Kuzeydoğu Akdeniz) Heterodinium Kofoid (Dinophyceae) cinsi için yeni kayıtlar

Dinoflagellat'lardan Heterodinium Kofoid cinsine ait üç tür Türkiye kıyısal sularında (kuzeydoğu Akdeniz) ilk kez rapor edilmiştir. Tanımlanan türler, Heterodinium mediocre Kofoid, H. angulatum Kofoid & Michener ve H. inaequale Kofoid türleridir. Bu üç türün karakteristik yapısal özellikleri tanımlanmış ve dağılımları ile ilgili bilgiler verilmiştir.Three species of the genus Heterodinium Kofoid are reported for the first time in Turkish coastal waters, in the north-eastern Mediterranean. The identified species are Heterodinium mediocre Kofoid, H. angulatum Kofoid & Michener and H. inaequale Kofoid. The morphological characteristics of these three species are described and information about their distribution is given

Türkiye kıyısal sularında dinoflagellat cinsi Histioneis F.R. von Stein (Dinophypceae) üzerine yeni kayıtlar

The dinoflagellate genus Histioneis F.R. von Stein 1883 and six species belonging to this genus are reported for the first time from the coastal waters of Turkey (north-eastern Mediterranean, lat. 36$\circ$ 06' N - 36$\circ$ 07' N, long. 33$\circ$ 28' E - 33$\circ$30' E). Descriptions of the species Histioneis depressa J.Schiller, H. expansa L.Rampi, H. para Murray & Whitting, H. marchesonii L.Rampi, H. striata Kof. & J.R.Michener and H. elongata Kof. & J.R.Michener are given.The dinoflagellate genus Histioneis F.R. von Stein 1883 and six species belonging to this genus are reported for the first time from the coastal waters of Turkey (north-eastern Mediterranean, lat. 36$\circ$ 06' N - 36$\circ$ 07' N, long. 33$\circ$ 28' E - 33$\circ$30' E). Descriptions of the species Histioneis depressa J.Schiller, H. expansa L.Rampi, H. para Murray & Whitting, H. marchesonii L.Rampi, H. striata Kof. & J.R.Michener and H. elongata Kof. & J.R.Michener are given

Kuzeydoğu Akdeniz'de (İskenderun Körfezi) fitoplanktonun mevsimsel değişimi

This study was carried out in the northern part of the Bay of Iskenderun in the northeastern Mediterranean during the period 1994-1995. The quantitative and qualitative distribution of phytoplankton, the environmental factors that affect its distribution and the changes in succession over time were investigated. At each of the seven stations, monthly sampling was done from the surface and 10.0 m depth. In spring, the sampling was performed once every two weeks. In addition, the measurements of some physical and chemical parameters i.e. temperature, salinity, ($NO^{-}_3$ +$NO^{-}_2$ )-N and $PO4^{-}_3$ -P were carried out. At the end of the study, a total of 170 taxa from 5 algae classes, Cyanophyceae, Dinophyceae, Prymnesiophyceae Dictyochophyceae and Bacillariophyceae were determined. Bacillariophyceae was found to be richer than the other groups in terms of abundance and species number and followed by Dinophyceae. Cyanophyceae, Prymnesiophyceae and Dictyochophyceae were represented by only one species each.This study was carried out in the northern part of the Bay of Iskenderun in the northeastern Mediterranean during the period 1994-1995. The quantitative and qualitative distribution of phytoplankton, the environmental factors that affect its distribution and the changes in succession over time were investigated. At each of the seven stations, monthly sampling was done from the surface and 10.0 m depth. In spring, the sampling was performed once every two weeks. In addition, the measurements of some physical and chemical parameters i.e. temperature, salinity, ($NO^{-}_3$ +$NO^{-}_2$ )-N and $PO4^{-}_3$ -P were carried out. At the end of the study, a total of 170 taxa from 5 algae classes, Cyanophyceae, Dinophyceae, Prymnesiophyceae Dictyochophyceae and Bacillariophyceae were determined. Bacillariophyceae was found to be richer than the other groups in terms of abundance and species number and followed by Dinophyceae. Cyanophyceae, Prymnesiophyceae and Dictyochophyceae were represented by only one species each

Corneal Pseudodendritic Lesions Masquerading as Herpetic Keratitis in a Patient With Tyrosinemia Type I

Objective: To describe the clinical findings of a patient with tyrosinemia type I with noncompliance to a protein-restricted diet, treated with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC)

Correlation Between Androgen Levels and Dry Eye Parameters in Male Patients with Chronic Obstructive Pulmonary Disease

Objective: To investigate the effects of chronic obstructive pulmonary disease (COPD) in the dry eye status in men and to determine whether the hypoandrogenic status has any concomitant impact