Journal of Qassim University for Science

Resonant Tunneling of Electrons and Holes through the AlGaAs/GaAsBi/AlGaAs Quantum Structure

Ahmed Rebey — 2024-10-27

In this paper, we report a quantitative study of a resonant tunneling diode (RTD) based on the AlGaAs/GaAsBi/AlGaAs structure as an active part of the device. First, the physical parameters of the GaAsBi alloy (bandgap energy, effective masses), to be used as input data for the calculation of transmission tunneling through the diode, are determined using the band anticrossing (BAC) approach. Second, we have calculated the I-V characteristic of RTD in order to analyze its performance via the values of peak-to-valley current ratio (PVCR) and negative differential conductance (NDC). Our calculation takes into account the effect of two types of carriers (electrons and holes) on the transport properties of the system. Remarkably, high performance (PVCR~450) is reached by optimizing the metallurgic and physical parameters of the structure. It is demonstrating that the incorporation of Bi in the GaAs matrix favors transport by holes and enhances the performance of RTD compared with standard one using electron conduction.

High dielectric and conduction proprieties of Na+-doped lanthanum Strontium manganite for cathode materials application

Rahma Brahem — 2024-10-27

In the present work, we were conducted to analyze the structural, conduction and dielectric behavior of the Na⁺-doped Lanthanum Strontium manganite ceramics synthesized using the sol-gel technology over broad temperature and frequency ranges. X-ray diffraction (XRD) at room temperature and Rietveld analysis reveals that La_0.7Sr_0.2Na_0.1MnO₃ crystallizes in a pure phase belonging to the rhombohedral structure with R-3c space group. Moreover, it is found that Size-Strain plot is the most appropriate technique to estimate the crystallite sizes and lattice strain effect. However, the analysis of electrical conductivity using several model of hopping process reflected the presence of significant charges mobility and a strong electron-phonon interaction. A quantitative investigation by the frequency exponents n(T) reveals that the conduction was overpowered by the Correlated Barrier Hopping (CBH) model while the scaling exponent (a) prove the validity of time-temperature superposition principle. The frequency dependence of the dielectric constant (ε'') was attributed to the chemical micro-heterogeneity explained by the interfacial polarization type given by Koop’s theory. Furthermore, the colossal behavior of dielectric constant (ε'') with a value over 10⁶ and the presence of high electrical conductivities of 0.043 S.cm^-1 denote a possibility application of this compound in the energy storage devices.

LSNMTix Contribution to the examination of the effect of Ti –substitution on the crystallographic and transport characteristics of

Rahma Brahem — 2024-10-28

A coherent inquiry of the microstructural, structural, hopping transport and dielectric relaxation behaviors in La_0.7Sr_0.25Na_0.05Mn_1-x Ti_xO₃ (LSNMTi_x) (x =0.0-0.2) was carried out to get new comprehension about the impacts of the physical interactions between the titanium and manganese cations on the hopping conductivity and dielectric relaxation features of manganites. LSNMTi_xwith x=0.0, and 0.2 are produced based on the ceramic solid-state reaction route. For the investigated compounds, X-ray diffraction data and the Rietveld analysis displayed the occurrence of a rhombohedral single phase with an Rcspace group. Using the SEM images, we found that the ceramics exhibit an average crystal size D_MEB that increases from 193 nm for LSNMTi_0.0to 230 nm for LSNMTi_0.2. Using the complex impedance and modulus studies, at room temperature, the obtained results revealed the presence of relaxation processes that are ascribed to the main roles of combined grains and grain boundary domains. The compound’s dielectric responses are explicated based on the phenomenological theory of Koop’s and via the model of Maxwell–Wagner. The electrical conductivity spectra are analyzed based on the power law of Jonscher. They confirm that the substitution by the Ti element reduces the electrical conductivity of the prepared system.

Pyrimidine-1,2,3-Triazole Hybrid Glycosides: Click Based Synthesis and Biological aspects

Mohamed EL-Bayaa — 2024-10-27

Application of click chemistry for the construction of hybrid structure incorporating 1,2,3-triazole nucleus was extensively studied as a powerful strategy for designing a variety of targeted structures. The currents review focused on the synthetic pathways of compounds possessing two important motifs: pyrimidine and 1,2,3-triazole systems and their derived sugar derivatives as glycoside analogues. The reported bioactivities of the formed hybrid products were highlighted.

Design, Characterization and Molecular Docking Study of the New Isoxazolidine-1,2,3-Triazole Hybrids

Kaiss Aouadi — 2024-10-27

Polycyclics are considered among the most widely used compounds in drug discovery. Isoxzolidine-triazole hybrids have multiple medicinal properties, including anti-inflammatory and anti-tumor agents. In this work, we synthesized a new series of isoxazolidine-triazole hybrids and study molecular docking of the synthesized compounds to determine the binding interactions with target protein PIKα (PDB ID: 3ZIM). With a docking score of -10.4 kcal/mol, 7e demonstrated good binding affinity to the active site of PI3K among all synthesized compounds.

. Click Chemistry: a promising approach for 1,2,3-triazole synthesis

Noora Al-Sahli — 2024-10-27

In this review we return to the click chemistry reaction and the importance of the compounds containing the 1,2,3-triazole cycle

Study of Boscia Senegalensis as a Coagulant to Remove Turbidity from Drinking Water

Abdelhamid Essa — 2024-10-27

The study's goal was to find out how well the powdered Boscia Senegalensis (Pers.) Lam. ex Poir plant works as a natural coagulant to remove turbidity in raw water and improve the quality of drinking water. They did this by testing different amounts of Boscia Senegalensis, leaves BSL, and barks BSB, with a starting turbidity level of 700–600 NTU. The jar tests were done with different amounts of flocculent 40 minutes after treatment (0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 g/l) to get rid of turbidity. The results of BSB powder were (24.74, 88.17, 87.87, 87.48, 88.33, 86.83, 82.00%) and BSL powder (22.91, 59.94, 67.63, 65.86, 64.26, 61.53, 54.33%), respectively. These results showed activity in turbidity removal; the dose of 0.8 g/l was the optimal amount of BSB, achieving 88.33%, and the optimal dose of BSL was 0.4 g/l, reaching 67.63%. Also, other parameters such as pH, alkalinity, and TDS showed a few changes in the pH from 8 to 7.7 in all different doses of BSB and BSL, and alkalinity from 92 to 90 mg/l for the BSB and 86 to 120 mg/l for the BSL. Alkalinity increases with increasing BSL and BSB doses. It was observed through the results that Boscia senegalensis has efficiency in removing turbidity. Still, BSB results were much better than BSL, which agrees with the previous study.

Metal complexes developing for ramipril determination in tablet by potentiometric technique

Anas Alfarsi — 2024-10-27

Three metallic ions viz; Cr⁺³, Fe ⁺³and Al⁺³ was nominated to clarify the relations of these metallic elements with ramipril (RAM) by means of potentiometric technique. The protonation constant of RAM and formation constants of complexes constructed at ionic strength (I = 0.1 M sodium nitrate) have been tabularized in aquatic medium at room temperature. The ratios of complexes 1:1, 1:2 and/or 1:3 metallic ions towards RAM relations are developed dependent on the nature of RAM or metallic ions. The order of formation constants of the two complexes was studied. The potentiometric method was employed to approve the ratios of M-RAM binary complexes formed. This method was used successfully to detect RAM in tablets. The standard addition process built on Gran plan, RAM was acceptably estimated at ionic strength I= 0.4 M NaNO₃, through a concentration variety of 0.753–12.05 mg/mL (standard deviation SD = 0.11, correlation coefficient R = 0.9992 (n = 5)) by a lower detection limit (LOD) equals 0.55 milligram/milliliters (standard deviation SD = 0.15, R = 0.9992 (n = 5)). In the presence of famous tablet excipients, no interfering was detected. The ratio of RAM gets back from tablet dosage forms diverse after 99.5 to 100.6 % with SD ranging from (0.39 – 0.7).

1,3,4-Thiadiazoles: Aryl, Heteroaryl and Glycosyl Hybrids Synthesis and Related Bioactivities

Ahmed M. Hussein — 2024-10-27

Developing novel therapeutics in different medicinal fields is ongoing need for control of various threats and disease. 1,3,4-Thiadiazole nucleus is a versatile scaffold in medicinal chemistry which could be located as separate ring, fused ring or newly emerged glycoside. Here, a look on some different preparation routes, biological activities of thiadiazole containing compounds and insights on the ring role from structure activity relationship view. Also, a view on newly emerged thiadiazole glycosides as strategy for enhancement activity of aglycan part of the target compound.

Synthesis, ADMET and pharmacokinetic analysis of new isoxazolidine-pyrazole hybrids

Siwar Ghannay — 2024-10-27

Interest in hybrid compounds containing two or more different rings continues to grow due to the impressive biological results that have been derived in numerous examples. In this work, we have synthesized new isoxazolidine-pyrazole hybrids and study ADMET and pharmacokinetic analysis. These results outlined that the titled compounds have good ADMET properties, which are a requisite for a molecule to show acceptable drug-like and pharmacokinetic properties.