Photoluminescence studies of selected styrylquinolinium thin films made using thermal evaporation deposition technique

In this paper we present a photoluminescence (PL) study of new styrylquinolinium dyes. We made a comparative study of the luminescent properties of thin films grown on quartz substrates using thermal evaporation deposition method. Investigated films show PL emission from the violet to near-IR region at room temperature

Effect of H2O2 pretreatment on the response of two seashore paspalum (Paspalum vaginatum Sw.) cultivars (Salam and Seaspray) to cold stress

Seashore paspalum is a warm season grass that requires few maintenance inputs. Expanded use of seashore paspalum could play a key role in making recreational sites more sustainable and environmentally. However, one key barrier to widespread Seashore paspalum use is a relative lack of winter hardiness. Under severe stress conditions, the antioxidant capacity may not be sufficient to minimize the harmful effect of oxidative injury. The search for signal molecules that mediate the stress tolerance is an important step in better understanding how plants acclimate to the adverse environment. This study aims to screen the responses of two Paspalum vaginatum cultivars (Salam and Seaspray) to local weather conditions and to study how to enhance its cold tolerance by a foliar pretreatment by hydrogen peroxide at low concentrations of 10 mM under controlled conditions. The current study provides evidence that exogenous H2O2 decreases the endogenous content of H2O2 in the first three days of exposure to cold stress in pretreated ‘Seaspray’ plants. in comparison to their control and pretreated ‘Salam’ which was in concomitant with malondialdehyde (MDA) changes. Indicating that pretreatment with 10 mM H2O2 could improve the tolerance of seashore paspalum to cold stress, especially cultivar Seaspray which showed better response to cold stress compared to ‘Salam’. Exogenous H2O2 could constitute a signaling molecule that significantly increases POD relative density, and decreases MDA and H2O2 content

Deep-level Transient Spectroscopy of GaAs/AlGaAs Multi-Quantum Wells Grown on (100) and (311)B GaAs Substrates

Si-doped GaAs/AlGaAs multi-quantum wells structures grown by molecular beam epitaxy on (100) and (311)B GaAs substrates have been studied by using conventional deep-level transient spectroscopy (DLTS) and high-resolution Laplace DLTS techniques. One dominant electron-emitting level is observed in the quantum wells structure grown on (100) plane whose activation energy varies from 0.47 to 1.3 eV as junction electric field varies from zero field (edge of the depletion region) to 4.7 × 106 V/m. Two defect states with activation energies of 0.24 and 0.80 eV are detected in the structures grown on (311)B plane. The Ec-0.24 eV trap shows that its capture cross-section is strongly temperature dependent, whilst the other two traps show no such dependence. The value of the capture barrier energy of the trap at Ec-0.24 eV is 0.39 eV

Novel Styrylquinolinium Dye Thin Films Deposited by Pulsed Laser Deposition for Nonlinear Optical Applications

The nonlinear optical (NLO) properties of novel styrylquinolinium dye thin films for photonic applications have been studied by the Z-scan, second harmonic generation (SHG), and third harmonic generation (THG) techniques, providing both the second- and third-order nonlinear optical parameters. The styrylquinolinium dye (E)-1-ethyl-4-(2-(4-hydroxynaphthalen-1-yl)vinyl)quinolinium bromide was synthesized by the Knoevenagel condensation, and its structure and physicochemical properties were determined by H-1 NMR, C-13 NMR, FTIR, UV-vis spectroscopy, and elemental analysis. Functional thin films were deposited by pulsed laser deposition (PLD) using UV TEA N-2 laser onto glass substrates and KCl, NaCl monocrystals at room temperature and vacuum at 10(-3) mbar/0.1 Pa. Further characterization of the films and target from native material by FTIR spectroscopy revealed that there was no difference between the deposited films and the initial material. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements have been also performed in order to provide information about the morphology and topology of the thin films

Genomics-assisted breeding in four major pulse crops of developing countries: present status and prospects

The global population is continuously increasing and is expected to reach nine billion by 2050. This huge population pressure will lead to severe shortage of food, natural resources and arable land. Such an alarming situation is most likely to arise in developing countries due to increase in the proportion of people suffering from protein and micronutrient malnutrition. Pulses being a primary and affordable source of proteins and minerals play a key role in alleviating the protein calorie malnutrition, micronutrient deficiencies and other undernourishment-related issues. Additionally, pulses are a vital source of livelihood generation for millions of resource-poor farmers practising agriculture in the semi-arid and sub-tropical regions. Limited success achieved through conventional breeding so far in most of the pulse crops will not be enough to feed the ever increasing population. In this context, genomics-assisted breeding (GAB) holds promise in enhancing the genetic gains. Though pulses have long been considered as orphan crops, recent advances in the area of pulse genomics are noteworthy, e.g. discovery of genome-wide genetic markers, high-throughput genotyping and sequencing platforms, high-density genetic linkage/QTL maps and, more importantly, the availability of whole-genome sequence. With genome sequence in hand, there is a great scope to apply genome-wide methods for trait mapping using association studies and to choose desirable genotypes via genomic selection. It is anticipated that GAB will speed up the progress of genetic improvement of pulses, leading to the rapid development of cultivars with higher yield, enhanced stress tolerance and wider adaptability

Оптимізація виявлення терагерцового сигналу в транзисторах з високою рухливістю електронів: висновки з досліджень плазмового резонансу

Проведено аналітичне моделювання досліджує резонансну поведінку плазмових хвиль у каналі транзисторів з високою рухливістю електронів (HEMT), коли вони піддаються терагерцевому (ТГц) збудженню. Основна мета полягає в систематичному дослідженні впливу різних параметрів HEMT на динаміку плазмового резонансу та виявлення ТГц сигналів. Найефективніше виявлення сигналів ТГц фіксується, коли і затвор, і термінали стоку одночасно отримують збудження ТГц. Крім того, модуляція умов зміщення, зокрема представлена поляризаційними напругами, суттєво впливає на частоти плазмового резонансу, пропонуючи багатообіцяючий шлях для адаптації відповідей HEMT. Подальше дослідження вказує на сильний вплив характеристик області доступу, включаючи довжину та концентрацію легування, на збудження тривимірних плазмових хвиль у HEMT, причому область доступу до стоку демонструє особливе значення. Крім того, детально вивчено розгалуження геометрії затвора, охоплюючи ширину та відстань від каналу до затвора, виявляючи їх здатність суттєво змінювати частоти 2D плазмового резонансу. У екстремальних випадках HEMT демонструє поведінку, подібну до спрощеної конфігурації діода, що призводить до відсутності 2D плазмового резонансу. Дане дослідження розкриває суттєві ідеї для проектування та оптимізації пристроїв на основі HEMT, адаптованих до конкретних додатків частоти ТГц. Це підкреслює ключову роль умов зміщення, властивостей області доступу та геометрії воріт у формуванні продуктивності HEMT і виявлення ТГц сигналу.This analytical modeling study delves into the resonance behavior of plasma waves within the channel of High Electron Mobility Transistors (HEMTs) when subjected to Terahertz (THz) excitation. The core objective is to systematically examine the influence of various HEMT parameters on the dynamics of plasma resonance and the detection of THz signals. A noteworthy finding emerges: the most effective detection of THz signals materializes when both the gate and drain terminals simultaneously receive the THz excitation. Moreover, the modulation of biasing conditions, specifically represented by polarization voltages, exerts a substantial influence on plasma resonance frequencies, offering a promising avenue for tailoring HEMT responses. Further exploration reveals the substantial impact of access region characteristics, including length and doping concentration, on the excitation of 3D plasma waves within the HEMT, with the drain access region demonstrating particular significance. Additionally, we delve into the ramifications of gate geometry, encompassing width and channel-to-gate distance, revealing their capacity to significantly alter 2D plasma resonance frequencies. In extreme cases, the HEMT exhibits behavior akin to a simplified diode configuration, resulting in the absence of 2D plasma resonance. In summation, this research unfolds essential insights for the design and optimization of HEMT-based devices tailored to specific THz frequency applications. It underscores the pivotal roles of biasing conditions, access region properties, and gate geometries in shaping HEMT performance and THz signal detection