jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Unarine Rambau | Nndivhaleni Anox Masevhe | Nneka Augustina Akwu | Amidou Samie
Source: Preprints.org (preprint, 2023-12-01)
Field: Materials Science — Materials Chemistry

Green Synthesis, Characterization and Antibacterial Activity of Gold and Copper Nanoparticles from Lannea discolor (Sond.) Engl Green synthesis using plant extracts has emerged as an eco-friendly, clean, and viable strategy alternative to chemical and physical approaches. The leaf, stem, and root extracts of Lannea discolor was utilized as a reducing and stabilizing agent in the synthesis of gold (AuNPs) and copper (CuNPs) nanoparticles. The formation of AuNPs and CuNPs confirmed by their color change, was characterised by UV–Vis Spectroscopy (UV- Vis), Scanning electron microscopy analysis and energy dispersive x-ray (SEM-EDX), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR), coupled with minimum concentration inhibitory (MIC) antibacterial assays. AuNFs, NPs and CuNPs peaked at wavelengths in the ranges of 316, 544 and 564 nm respectively. TEM showed unexpected nanoflowers (30 – 97 nm) in the leaf extracts and spherical NPs (10 -33 nm; 9.3 – 37.5) from stem and root extracts, while spherical CuNPs (20 – 104 nm), were observed from all the extracts. EDX was able to confirm the presence of metal salts and FTIR revealed stable capping agents. AuNPs and NFs from L. discolor extracts showed appreciable antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Bacillus subtilis, when compared to the plant extracts, while none was observed from the CuNPs. These AuNPs and CuNPs are particularly appealing in a variety of applications in the biomedical as well as conductivity manufacturing, due to their shapes and sizes and economical and environmentally friendly production. Fourier transform infrared spectroscopy ; Nuclear chemistry ; Antibacterial activity ; Colloidal gold ; Reducing agent ; Nanoparticle ; Transmission electron microscopy ; Chemistry ; Copper ; Scanning electron microscope ; Materials science ; Bacteria ; Nanotechnology ; Organic chemistry ; Chemical engineering ; Biology Nanoparticles: synthesis and applications ; Moringa oleifera research and applications ; Essential Oils and Antimicrobial Activity
Authors: Christian Tobeck | Heiko Wende | Uwe Ruschewitz
Source: Inorganics (article, 2023-11-25)
Field: Materials Science — Materials Chemistry

Solid Solutions LnxU1−xC2 with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal Vegard Behavior The reaction of UO2 with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition LnxU1−xC2, with Ln = Tb, Dy, Ho, Tm, and Lu. They all crystallize in the tetragonal CaC2 type structure (I4/mmm, Z = 2). Elemental analyses of selected samples (EDX) confirm that the composition of the resulting solid solution is in reasonable agreement with the nominal (weighed-in) composition of the starting materials, i.e., a significant evaporation of the lanthanide metals during the arc-melting synthesis does not occur. The lattice parameters of the solid solutions were extracted using Le Bail fits of high-resolution synchrotron powder diffraction data (beamline P02.1, DESY, Hamburg, Germany; beamline BL 09, DELTA, Dortmund, Germany), revealing ideal Vegard behavior for all five solid solutions. XANES investigations on all compounds at the Ln-LIII and U-LIII edges reveal that the occupancies of the U-6d orbitals decrease with increasing x, whereas the occupancies of the Ln-5d orbitals increase, pointing to an electron transfer from the uranium to the lanthanide cations. Examination of the shifts of the absorption edge (E0) leads to the same finding. Lanthanide ; Solid solution ; Chemistry ; Analytical Chemistry (journal) ; Crystallography ; Tetragonal crystal system ; XANES ; Materials science ; Spectroscopy ; Crystal structure ; Physics Nuclear Materials and Properties ; Fusion materials and technologies ; Rare-earth and actinide compounds
Authors: Peng Meng | Andreis Lau | Daigo Miyajima | Parvej Alam | Zijie Qiu | Ben Zhong Tang
Source: ChemRxiv (preprint, 2023-10-25)
Field: Materials Science — Materials Chemistry

Modulating Molecular Aggregation of Luminogens: Bridging the Gap Between Solutions and Solids In the past two decades, the advancement of aggregation-induced emission (AIE) has greatly advanced our understanding of organic luminescence and facilitated the application of organic luminescent materials. AIEgens emit weakly in solutions but strongly in aggregated states. This significant difference in luminescence between solutions and aggregated states of AIEgens has shown that there is much to explore in the mesoscopic world (the intermediary phase). Accordingly, the research paradigm is shifting towards aggregate science. The path to new aggregate materials relies not only on molecule syntheses but also on the control of molecular aggregation. Molecular aggregation bridges the gap between solutions and solids, which is of great significance for developing aggregate science. In this perspective, we outline three general strategies for managing molecular aggregation to stimulate new ideas and provide guidance on controllable molecular aggregation. Mesoscopic physics ; Bridging (networking) ; Aggregation-induced emission ; Luminescence ; Aggregate (composite) ; Nanotechnology ; J-aggregate ; Chemical physics ; Molecule ; Materials science ; Chemistry ; Computer science ; Physics ; Optoelectronics ; Quantum mechanics ; Organic chemistry Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Molecular Sensors and Ion Detection
Authors: Murat Aycibin | Mehmet Erzen | Harun Akkuş
Source: Processing and Application of Ceramics (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Theoretical prediction by DFT on properties of β′-SrTa2O6 crystal Based on the Density Functional Theory (DFT) electronic band structure, state density, linear optics, elastic, dynamic and thermodynamic properties of ??-SrTa2O6 crystal with P4/mbm (No. 127) space group were investigated with the help of ABINIT and Wien2k code. In the study, it was found that the ??-SrTa2O6 crystal is classified as a semiconductor with an indirect bandgap. For this crystal, the dielectric function was obtained and optical constants such as energy loss function, extinction coefficient, absorption coefficient and reflectivity were calculated. The components of the elastic stiffness tensor, the phonon dispersion, the state density and the contribution of each atom to the state density were obtained. Finally, thermodynamic properties were determined for the ??-SrTa2O6 crystal. Furthermore, the changes in free energy (F), internal energy (E), entropy (S) and heat capacity (C) depending on the temperature were investigated. Materials science ; Density functional theory ; WIEN2k ; Band gap ; Crystal (programming language) ; Thermodynamics ; Density of states ; Heat capacity ; Phonon ; Dielectric ; Attenuation coefficient ; Condensed matter physics ; Optics ; Local-density approximation ; Computational chemistry ; Physics ; Chemistry Luminescence Properties of Advanced Materials ; Microwave Dielectric Ceramics Synthesis ; Electronic and Structural Properties of Oxides
Authors: Xiaoying He | Mengxian Yu | Jian‐Peng Han | Jie Jiang | Qingzhu Jia | Qiang Wang | Zheng‐Hong Luo | Fangyou Yan | Yin‐Ning Zhou
Source:  (preprint, 2023-10-29)
Field: Materials Science — Materials Chemistry

Leveraging Data-Driven strategy for Accelerating the Discovery of Polyesters with Targeted Glass Transition Temperatures To overcome the limitations of empirical synthesis and expedite the discovery of new polymers, this work aims to develop a data-driven strategy for profoundly aiding in the design and screening of novel polyester materials. Initially, we collected 695 polyesters with their associated glass transition temperatures (Tgs) to develop a quantitative structure-property relationship (QSPR) model. The model underwent rigorous validation (external validation, internal validation, Y-random and application domain analysis) to demonstrate its robust predictive capabilities and high stability. Subsequently, by employing an in-silico retrosynthesis strategy, over 95000 virtual polyesters were designed, largely expanding the available space for polyester materials. External assessments highlight the good extrapolation ability of the QSPR model. Furthermore, we experimentally synthesized diverse virtual polyesters with Tgs covering a sufficient large temperature range. It is believed that this data-driven approach can drive future product development of polymer industry. Polyester ; Extrapolation ; Quantitative structure–activity relationship ; Glass transition ; Computer science ; Biochemical engineering ; In silico ; Applicability domain ; Polymer ; Experimental data ; Materials science ; Process engineering ; Nanotechnology ; Chemistry ; Machine learning ; Engineering ; Mathematics ; Composite material Machine Learning in Materials Science ; biodegradable polymer synthesis and properties ; Advanced Polymer Synthesis and Characterization
Authors: Tianbo Li | Min Lin | Zheyuan Hu | Kunhao Zheng | Giovanni Vignale | Kenji Kawaguchi | A. H. Castro Neto | Kostya S. Novoselov | Shuicheng Yan
Source: arXiv (Cornell University) (preprint, 2023-03-01)
Field: Materials Science — Materials Chemistry

D4FT: A Deep Learning Approach to Kohn-Sham Density Functional Theory Kohn-Sham Density Functional Theory (KS-DFT) has been traditionally solved by the Self-Consistent Field (SCF) method. Behind the SCF loop is the physics intuition of solving a system of non-interactive single-electron wave functions under an effective potential. In this work, we propose a deep learning approach to KS-DFT. First, in contrast to the conventional SCF loop, we propose to directly minimize the total energy by reparameterizing the orthogonal constraint as a feed-forward computation. We prove that such an approach has the same expressivity as the SCF method, yet reduces the computational complexity from O(N^4) to O(N^3). Second, the numerical integration which involves a summation over the quadrature grids can be amortized to the optimization steps. At each step, stochastic gradient descent (SGD) is performed with a sampled minibatch of the grids. Extensive experiments are carried out to demonstrate the advantage of our approach in terms of efficiency and stability. In addition, we show that our approach enables us to explore more complex neural-based wave functions. Density functional theory ; Kohn–Sham equations ; Computation ; Energy functional ; Gradient descent ; Computer science ; Artificial neural network ; Applied mathematics ; Mathematics ; Algorithm ; Physics ; Artificial intelligence ; Quantum mechanics ; Mathematical analysis Machine Learning in Materials Science ; Quantum many-body systems ; Physics of Superconductivity and Magnetism
Authors: А.И. Фрумен
Source: МОРСКИЕ ИНТЕЛЛЕКТУАЛЬНЫЕ ТЕХНОЛОГИИ (article, 2023-11-26)
Field: Materials Science — General Materials Science

Stress state of thick-walled polymer spherical shell under internal pressure В работе рассмотрено напряженно-деформированного состояния толстостенной полимерной сферической оболочки, находящейся под внутренним давлением. Отмечается, в связи с нелинейностью задачи, неприменимость «котельных» формул. Получена аппроксимация радиальных перемещений (квадратичный полином) и тангенциальных напряжений (гиперболическая зависимость) в зависимости от отношения толщины оболочки к ее радиусу. Проведены расчеты прочности и устойчивости сферического сосуда диаметром 1.6 метра, находящегося под внутренним давлением. Сравнение полученных результатов по аналитическим зависимостям (объемная задача теории упругости) и численным, выполненных по методу конечного элемента с пятью конечными элементами по толщине в расчетной модели, выявило прекрасную согласованность. Отмечается необходимость при расчете конкретных объектов обращать особое внимание на зоны с концентрацией напряжений. Показана возможность потери устойчивости толстостенной полимерной сферической оболочки, даже находящейся под внутренним давлением. The paper considers the stress-strain state of a thick-walled polymer spherical shell under internal pressure. It is noted, due to the nonlinearity of the problem, the inapplicability of "boiler" formulas. An approximation of radial displacements (quadratic polynomial) and tangential stresses (hyperbolic dependence) depending on the ratio of the thickness of the shell to its radius is obtained. Calculations of the strength and stability of a spherical vessel with a diameter of 1.6 meters, which is under internal pressure, are carried out. Comparison of the results obtained by analytical dependencies (the volumetric problem of the theory of elasticity) and numerical, performed by the finite element method with five finite elements in thickness in the computational model, revealed excellent consistency. It is noted that it is necessary to pay special attention to zones with stress concentration when calculating specific objects. The possibility of loss of stability of a thick-walled polymer spherical shell, even under internal pressure. Internal pressure ; Materials science ; Pressure vessel ; Spherical shell ; Elasticity (physics) ; Shell (structure) ; Finite element method ; Stress (linguistics) ; Mechanics ; RADIUS ; Polymer ; Stress–strain curve ; Composite material ; Mathematics ; Deformation (meteorology) ; Thermodynamics ; Physics Material Properties and Applications ; Structural mechanics and materials ; Advanced Theoretical and Applied Studies in Material Sciences and Geometry
Authors: S. L. Ilmenkov
Source: МОРСКИЕ ИНТЕЛЛЕКТУАЛЬНЫЕ ТЕХНОЛОГИИ (article, 2023-11-26)
Field: Materials Science — General Materials Science

Calculation of sound reflection characteristics on an elastic gas-filled cylindrical shell Представлено строгое решение задачи отражения стационарного звукового сигнала от бесконечной изотропной цилиндрической оболочки. В качестве заполнителя оболочки рассматривается газ, жидкость или полая упругая оболочка меньшего диаметра. Решение получено в рамках динамической теории упругости с использованием уравнения движения Ламе для изотропной среды, а также разложений упругих потенциалов и звуковых давлений по фундаментальным решениям уравнения Гельмгольца. Граничные условия относительно напряжений и смещений формулируются для каждой из поверхностей контакта оболочек с соответствующей средой. Подстановка разложений потенциалов в граничные условия позволяет получить системы алгебраических уравнений для нахождения неизвестных коэффициентов разложений и рассчитать значения звукового давления в отраженной волне. Вычислены и проанализированы частотные зависимости отраженного звукового сигнала для различных вариантов и параметров заполнения оболочки. A rigorous solution of the problem of reflection of a stationary sound signal from an infinite isotropic cylindrical shell they presented. A gas, liquid, or hollow elastic shell of a smaller diameter we considered as a shell filler. The solution we obtained within the framework of the dynamic theory of elasticity using the Lame equation of motion for an isotropic medium, as well as decompositions of elastic potentials and sound pressures by fundamental solutions of the Helmholtz equation. Boundary conditions with respect to stresses and displacements they formulated for each of the contact surfaces of the shells with the corresponding medium. Substituting potential expansions into boundary conditions allows us to obtain systems of algebraic equations for finding unknown coefficients of expansions and calculate the values of sound pressure in the reflected wave. The frequency dependences of the reflected sound signal for various options and parameters of shell filling are calculated and analyzed. Isotropy ; Shell (structure) ; Helmholtz equation ; Elasticity (physics) ; Boundary value problem ; Reflection (computer programming) ; Helmholtz free energy ; Acoustic wave ; Algebraic equation ; Mechanics ; Physics ; Classical mechanics ; Mathematical analysis ; Materials science ; Acoustics ; Mathematics ; Optics ; Thermodynamics ; Composite material Material Properties and Applications ; Arctic and Antarctic ice dynamics
Authors: Madhu Kanchrana | Gamidi Rama Krishna | Jyothi Kumari | Dharmarajan Sri | Srinivas Basavoju
Source: Research Square (preprint, 2023-08-08)
Field: Chemistry — Organic Chemistry

Synthesis, Anti-mycobacterial activity, Molecular Docking and ADME analysis of spiroquinoxaline-1,2,4-oxadiazoles via [3+2] cycloaddition reaction under ultrasound irradiation Abstract A convenient ultrasound methodology was employed to attain spiroquinoxaline-1,2,4-oxadiazoles via [3+2] cycloaddition of quinoxalineSchiff bases and aryl nitrile oxides at room temperature. This approach evades standard heating and column chromatography while producing high yields and lesser reaction times. The target compounds 3a-p were well characterized and their in vitro anti-mycobacterial activity (anti-TB) was evaluated. Among the screened compounds 3i has displayed promising activity against Mycobacterium tuberculosis cell line H37Rv with MIC value 0.78 µg/mL. However, three compounds ( 3f, 3h and 3o ) exhibited potent activity with MIC value 6.25 µg/mL. To further understand the binding interactions, the synthesized compounds were docked against the tuberculosisprotein 5OEQ using in silico molecular docking. Moreover, the utmost active compounds were additionally partitioned for their cytotoxicity against RAW 264.7 cell line, which revealed that the compounds 3f , 3h , 3i and 3o were less harmful to humans. Furthermore, the synthesized compounds were tested for ADME qualities, and the results suggest that this series is useful to produce innovative and potent anti-tubercular medicines in the future. ADME ; Cycloaddition ; In silico ; Chemistry ; Docking (animal) ; Mycobacterium tuberculosis ; Combinatorial chemistry ; In vitro ; Cytotoxicity ; Stereochemistry ; Biochemistry ; Tuberculosis ; Catalysis ; Veterinary medicine Synthesis and Biological Evaluation ; Synthesis and biological activity ; Multicomponent Synthesis of Heterocycles
Authors: Mustafa Ibrahim Khaleel | Pervin Soylu
Source: Research Square (preprint, 2023-01-12)
Field: Chemistry — Electrochemistry

A functional electrochemical sensing platform for the detection of lead ions Abstract A novel electrochemical sensor for the detection of lead ions was constructed by using electrodeposition of gold nanoparticles (GNPs) and glutathione (GSH) onto reduced graphene oxide (rGO) to form a GSH@GNP@rGO nanocomposite on a glassy carbon electrode (GSH@GNP@rGO@GCE). The sensing properties of the obtained sensor were tested by Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Under optimized experimental conditions, the voltammetry response gradually raises by increasing the concentration (2-20 μΜ). The result showed that the GSH@GNP@rGO@GCE sensor exhibited high sensitivity towards Pb(II) with a low detection limit of 0.43 μMby DPV. Our studies suggest that the GSH@GNP@rGO nanocomposite could potentially be used for detecting Pb(II). Differential pulse voltammetry ; Graphene ; Detection limit ; Cyclic voltammetry ; Nanocomposite ; Electrochemical gas sensor ; Electrochemistry ; Voltammetry ; Oxide ; Materials science ; Glutathione ; Inorganic chemistry ; Electrode ; Nuclear chemistry ; Chemistry ; Nanotechnology ; Chromatography ; Metallurgy ; Organic chemistry ; Physical chemistry Electrochemical Analysis and Applications ; Electrochemical sensors and biosensors ; Conducting polymers and applications
Authors: Ting Yu Teo | Nanxi Li | Landobasa Y. M. Tobing | Amy S. K. Tong | Doris K. T. Ng | Zhihao Ren | Chengkuo Lee | Lennon Y. T. Lee | Robert E. Simpson
Source: arXiv (Cornell University) (preprint, 2023-05-05)
Field: Materials Science — Materials Chemistry

Capping Layer Effects on $Sb_{2}S_{3}$-based Reconfigurable Photonic Devices Capping layers are essential for protecting phase change materials (PCMs) used in non-volatile photonics technologies. This work demonstrates how $(ZnS)_{0.8}-(SiO_2)_{0.2}$ caps radically influence the performance of $Sb_{2}S_{3}$ and Ag-doped $Sb_{2}S_{3}$ integrated photonic devices. We found that at least 30 nm of capping material is necessary to protect the material from Sulfur loss. However, adding this cap affects the crystallization temperatures of the two PCMs in different ways. The crystallization temperature of $Sb_{2}S_{3}$ and Ag-doped $Sb_{2}S_{3}$ increased and decreased respectively, which is attributed to interfacial energy differences. Capped and uncapped Ag-doped $Sb_{2}S_{3}$ microring resonator (MRR) devices were fabricated and measured to understand how the cap affects the device performance. Surprisingly, the resonant frequency of the MRR exhibited a larger red-shift upon crystallization for the capped PCMs. This effect was due to the cap increasing the modal overlap with the PCM layer. Caps can, therefore, be used to provide a greater optical phase shift per unit length, thus reducing the overall footprint of these programmable devices. Overall, we conclude that caps on PCMs are not just useful for stabilizing the PCM layer, but can also be used to tune the PCM crystallization temperature and reduce device footprint. Moreover, the capping layer can be exploited to enhance light-matter interactions with the PCM element. Materials science ; Crystallization ; Optoelectronics ; Layer (electronics) ; Doping ; Photonics ; Photonic crystal ; Phase (matter) ; Resonator ; Nanotechnology ; Chemical engineering ; Chemistry Phase-change materials and chalcogenides ; Photonic and Optical Devices ; Chalcogenide Semiconductor Thin Films