Homogeneous Composition Research Articles

Challenges and Prospects of DNA-Encoded Library Data Interpretation.

DNA-encoded library (DEL) technology is a powerful platform for the efficient identification of novel chemical matter in the early drug discovery process enabled by parallel screening of vast libraries of encoded small molecules through affinity selection and deep sequencing. While DEL selections provide rich data sets for computational drug discovery, the underlying technical factors influencing DEL data remain incompletely understood. This review systematically examines the key parameters affecting the chemical information in DEL data and their impact on hit triaging and machine learning integration. The need for rigorous data handling and interpretation is emphasized, with standardized methods being critical for the success of DEL-based approaches. Major challenges include the relationship between sequence counts and binding affinities, frequent hitters, and the influence of factors such as inhomogeneous library composition, DNA damage, and linkers on binding modes. Experimental artifacts, such as those caused by protein immobilization and screening matrix effects, further complicate data interpretation. Recent advancements in using machine learning to denoise DEL data and predict drug candidates are highlighted. This review offers practical guidance on adopting best practices for integrating robust methodologies, comprehensive data analysis, and computational tools to improve the accuracy and efficacy of DEL-driven hit discovery.

Tailoring the structure of Al50Mo50 alloy films towards realizing the well match between mechanical and electrical performance by controlling the growth mode

Metal films that combine superior mechanical properties with good conductivity are crucial for fulfilling the structural and functional requirements for MEMS applications. To achieve this, single-phase supersaturated solid solution Al50Mo50 alloy films were synthesized using magnetron sputtering at room temperature. By varying the deposition rate, the growth mode of these films was systematically controlled. The results demonstrate that there is no segregation in any of the films, which maintain homogeneity in composition and exhibit unexpected thermal stability at 550℃. As the deposition rate increases, the growth mode of the films transitions from a nano-columnar crystal structure to a layered + island structure. The supersaturated solid solution Al50Mo50 alloy film featuring a layered + island structure exhibits notable properties: high hardness (11.86GPa), high elastic modulus (194.27GPa), excellent ductility with a critical strain of 1.5%, and exceptionally low resistivity (100.95 μΩ cm). This combination of mechanical and electrical properties ensures a well-balanced performance suitable for MEMS applications. Moreover, the controlled process of the growth model and the optimization mechanism for enhanced ductility are systematically elucidated. These findings identify Al50Mo50 alloy films as an ideal candidate material for the design and development of MEMS/NEMS devices.

Dependence of rheological characteristics of epoxy adhesive binder on the degree of homogeneity of the premix composition

Dependence of rheological characteristics of epoxy adhesive binder on the degree of homogeneity of the premix composition

Improving compositional homogeneity of CF53 steel products by modifying their solidification structure and F-EMS intensity

In this article, based on the mechanism of stirring induced solute washing, the solidification characteristics of CF53 steel for camshafts were systematically studied through industrial casting tests and numerical simulations, focusing on the impact of solidification structure and final electromagnetic stirring (F-EMS) on solute distribution homogeneity in the core area of the bloom casting. The results indicate that excessive columnar crystal development, coupled with inappropriate use of F-EMS, can lead to significant negative segregation in the bloom, resulting in the formation of “white bands” in the following rolling bar products. Compared with weak stirring, strong stirring can affect solutes at deeper levels between dendrites. By reducing superheat and casting speed, expanding the equiaxed crystal zone in the bloom's centre, and carefully controlling the stirring intensity of F-EMS to position the molten steel washing in the equiaxed crystal zone, along with maintaining a maximum tangential velocity of 0.0041 m/s, a substantial improvement in solute distribution homogeneity within the bloom's core area was achieved. The carbon range can be reduced from 0.093% to 0.032%. These findings offer a theoretical foundation and practical suggestions for enhancing the quality of CF53 steel bloom castings and their hot-rolled bar products used in camshaft manufacture.

Synthesis Methods of Si/C Composite Materials for Lithium-Ion Batteries

Silicon anodes present a high theoretical capacity of 4200 mAh/g, positioning them as strong contenders for improving the performance of lithium-ion batteries. Despite their potential, the practical application of Si anodes is constrained by their significant volumetric expansion (up to 400%) during lithiation/delithiation, which leads to mechanical degradation and loss of electrical contact. This issue contributes to poor cycling stability and hinders their commercial viability, and various silicon–carbon composite fabrication methods have been explored to mitigate these challenges. This review covers key techniques, including ball milling, spray drying, pyrolysis, chemical vapor deposition (CVD), and mechanofusion. Each method has unique benefits; ball milling and spray drying are effective for creating homogeneous composites, whereas pyrolysis and CVD offer high-quality coatings that enhance the mechanical stability of silicon anodes. Mechanofusion has been highlighted for its ability to integrate silicon with carbon materials, showing the potential for further optimization. In light of these advancements, future research should focus on refining these techniques to enhance the stability and performance of Si-based anodes. The optimization of the compounding process has the potential to enhance the performance of silicon anodes by addressing the significant volume change and low conductivity, while simultaneously addressing cost-related concerns.

Synthesis of group-IV ternary and binary semiconductors using epitaxy of GeH3Cl and SnH4

Ge1−x−ySixSny alloys were grown on Ge buffers via reactions of SnH4 and GeH3Cl. The latter is a new CVD source designed for epitaxial development of group-IV semiconductors under low thermal budgets and CMOS-compatible conditions. The Ge1−x−ySixSny films were produced at very low temperatures between 160 and 200 °C with 3%–5% Si and ∼5%–11% Sn. The films were characterized using an array of structural probes that include Rutherford backscattering, x-ray photoelectron spectroscopy, high-resolution x-ray diffraction, scanning transmission electron microscopy, and atomic force microscopy. These studies indicate that the films are strained to Ge and exhibit defect-free microstructures, flat surfaces, homogeneous compositions, and sharp interfaces. Raman was used to determine the compositional dependence of the vibrational modes indicating atomic distributions indistinguishable from those obtained when using high-order Ge hydrides. For a better understanding of the growth mechanisms, a parallel study was conducted to investigate the GeH3Cl applicability for synthesis of binary Ge1−ySny films. These grew strained to Ge, but with reduced Sn compositions and lower thicknesses relative to Ge1−x−ySixSny. Bypassing the Ge buffers led to Ge1−ySny-on-Si films with compositions and thicknesses comparable to Ge1−ySny-on-Ge; but their strains were mostly relaxed. Efforts to increase the concentration and thickness of Ge1−ySny-on-Si resulted in multiphase materials containing large amounts of interstitial Sn. These outcomes suggest that the incorporation of even small Si amounts in Ge1−x−ySixSny might compensate for the large Ge–Sn mismatch by lowering bond strains. Such an effect reduces strain energy, enhances stability, promotes higher Sn incorporation, and increases critical thickness.

Thermally-induced diffusion and structural phase transitions in Pt/Mn and Pt/Mn/Pt thin films

We demonstrate the possibility of diffusion formation of the chemically ordered L1 0-MnPt phase through the vacuum annealing of Pt(24 nm)/Mn(20 nm) and Pt(12 nm)/Mn(20 nm)/Pt(12 nm) layered stacks at 400 °C for 30 min. For the bi-layered stack annealed at 400 °C, the effect of Pt atoms segregation at the film/substrate interface was detected, which remained after annealing even at higher temperatures (500 °C and 600 °C) and prevented the whole homogenization of the chemical composition through the film depth. By contrast, for the tri-layered stack annealed at 400 °C, the presence of the additional Pt bottom layer enabled to change the rate and mechanism of reactive diffusion, leading to homogeneous distribution of components and enhanced crystallinity of the ordered L1 0-MnPt phase compared to the bi-layered sample. An explanation of the obtained experimental data is provided based on the fundamentals of mass transfer theory and its quantitative parameters (e.g. activation energy and diffusion coefficients).

Effect of Horizontal Continuous Casting Parameters on Cyclic Macrosegregation, Microstructure, and Properties of High-Strength Cu–Mg Alloy Cast Rod

AbstractThe objective of this paper is to present the effect of horizontal continuous casting parameters on macrosegregation and its effect on microstructures, textures, mechanical properties, and electrical resistivity of Cu–Mg alloy rod. By increasing the pulling distance and intermittent extraction time, chemical macrosegregation was observed along the longitudinal section of the cast rod, which reached a distance of 40 mm. Three areas were identified along the length of the material, especially at high pulling distance: with decreasing, quasi-stable, and increasing Mg concentration area. As the pulling distance increased, the difference in the observed extreme values of Mg concentration increased. Two distinct zones of different grain size were also observed. The first zone was formed of large columnar grains with a preferred direction of solidification $$\langle 100\rangle$$ ⟨ 100 ⟩ inclined to the axis of the wire, followed by a second zone formed of small grains of random texture. Consequently, difference in resistivity occurred from one zone to another and the resistivity increased from 37.5 to 41 nΩm. Likewise, the hardness varied between the values of 90 up and 110 Hv. The most homogenous chemical composition was obtained with up to 6 mm of pulling distance and up to 3 seconds of intermittent extraction time.

Effects of TMIn Flow Rate During Quantum Barrier Growth on Multi-quantum Well Material Properties and Device Performance in GaN-Based Laser Diodes

Abstract Multidimensional influence of indium composition in barrier layers on GaN-based blue laser diodes (LDs) are discussed through both material quality and device physics perspectives. LDs with higher indium content in the barriers demonstrate a notably lower threshold current and shorter lasing wavelength compared to those with lower indium content. Our experiments reveal that higher indium content in the barrier layers can partially reduce indium composition in the quantum wells, a novel discovery. Employing higher indium content barrier layers leads to improved luminescence properties of MQW region. Detailed analysis reveals that this improvement can be attributed to better homogeneity in the indium composition of the well layers along the epitaxy direction. InGaN barrier layers suppressed lattice mismatch between barrier and well layers, thus mitigating the indium content pulling effect in well layers. In supplement to experimental analysis, theoretical computations are performed, showing that InGaN barrier structures can effectively enhance carrier recombination efficiency and optical confinement of LD structure, thus improving output efficiency of GaN-based blue LDs. Combining these theoretical insights with our experimental data, we propose that higher indium content barriers effectively enhance carrier recombination efficiency and indium content homogeneity in quantum well layers, thereby improving the output performance of GaN-based blue LDs.

Imaging Locally Inhomogeneous Properties of Metal Halide Perovskites.

Metal halide perovskites (MHPs) are a perfect example of state-of-the-art photovoltaic materials whose compositional and structural diversity,coupled with utilization of low-temperature processing, can undesirably result in spatially inhomogeneous properties that locally vary within the material. This complexity of MHPs requires sensitive imaging characterization methods at the microscopic level to gauge the impact of such inhomogeneities on device performance and to formulate mitigation strategies. This review consolidates properties of MHPs that are susceptible to local variations and highlights appropriate imaging techniques that can be employed to map them. Inhomogeneities in morphology, emission, electrical response, and chemical composition of MHP thin films are specifically considered, and possible microscopic techniques for their visualization are reviewed. For each type of microscopy, a short discussion about spatial resolution, sample requirements, advantages, and limitations is provided, thus leaving the reader with a guide of available imaging characterization tools to evaluate inhomogeneities of their MHPs.

Tailoring the coefficient of thermal expansion in a functionally graded material: Al alloyed with Ti-6Al-4V using additive manufacturing

Functionally graded materials enable the spatial tailoring of properties through controlling compositions and phases that appear as a function of position within a component. The present study investigates the ability to reduce the coefficient of thermal expansion (CTE) of an aluminum alloy, Al 2219, through additions of Ti-6Al-4V. Thermodynamic simulations were used for phase predictions, and homogenization methods were used for CTE predictions of the bulk CTE of samples spanning compositions between 100 wt% Al 2219 and 70 wt% Al 2219 (balance Ti-6Al-4V) in 10 wt% increments. The samples were fabricated using directed energy deposition (DED) additive manufacturing (AM). Al2Cu and fcc phases were experimentally identified in all samples, and aluminides were shown to form in the samples containing Ti-6Al-4V. Thermomechanical analysis was used to measure the CTE of the samples, which agreed with the predicted CTE values from homogenization methods. The present study demonstrates the ability to tailor the CTEs of samples through compositional modification, thermodynamic calculations, and homogenization methods for property predictions.

Vertical Compositional Heterogeneity Induces Instability in All-Inorganic CsPbIBr2 Perovskites.

Understanding the vertical compositional homogeneity and defect distribution is of paramount importance in elucidating and maximizing the performance of halide-perovskite-based optoelectronic devices. This work reports the depth-dependent study of the chemical composition and metallic Pb0 content of all-inorganic CsPbIBr2 perovskite films undertaken using lab-based hard X-ray photoelectron spectroscopy and soft X-ray photoelectron spectroscopy. The presence of elemental or metallic Pb (Pb0), in the bulk and at the surface of the perovskite films highlights the formation of defect or recombination centers throughout the analyzed depth. The Pb0 content was found to be of higher concentration in the bulk of the CsPbIBr2 films compared to that at the surface. Engineering the CsPbIBr2 film growth using appropriate antisolvents resulted in the overall reduction and/or complete elimination of Pb0 at the surface and at the bulk of the perovskite films. However, the effect of antisolvent treatment was significantly pronounced in the bulk-like region as compared to that at the surface. Pb0 is synonymous with defect states/recombination centers in perovskite films and this reduction in defect density due to the antisolvent treatment corroborates the enhanced phase stability and improved solar cell performance of the corresponding CsPbIBr2 devices.

Selective area epitaxy of gallium phosphide-based nanostructures on microsphere lithography-patterned Si wafers for visible light optoelectronics

In this study, we present the selective area plasma-assisted molecular beam epitaxial growth of GaP-based nanoheterostructures (nanostubs), incorporating direct bandgap GaAsP or GaPN segments, on patterned SiO2/Si(001) wafers. A microsphere optical lithography and anisotropic Si wet-etching techniques were employed for wafer-scale surface patterning through SiO2 growth mask, allowing to obtain either planar or pyramidal pit nucleation site morphologies. X-ray diffraction reciprocal space mapping and Raman microspectroscopy studies confirm compositional homogeneity of the nanostub arrays. The dilute nitride nanostubs display the narrowest and most intense visible red photoluminescence response at room temperature, which is an order of magnitude higher compared to the GaAsP ones. The formation of the nitrogen sub-band in GaPN alloy was confirmed in the framework of density functional theory, providing insights for interpreting the experimental results. These findings demonstrate the feasibility of the proposed approach for fabricating the ordered arrays of nanoscale visible light emitters on silicon.

Synthesis, characterization, and photocatalytic performance of gold ions implanted TiO2/graphene nanocomposites for efficient dye photodegradation

The suggested work provides a hydrothermal technique for the synthesis of TiO2/graphene nanocomposites with different weight percentages of graphene (0.0 %, 5.0 %, 10.0 %, and 15.0 %). These composites were implanted with gold ions at a fluence of 1 × 1013 ions/cm2 by using a pelletron accelerator. The structural and physical properties were investigated by utilizing XRD, FESEM, FTIR, EDX, and UV–Vis spectroscopy. The XRD data verified the existence of TiO2 with a rutile crystal phase. FESEM morphology showed that TiO2 particles had aggregated on graphene layers and had a semi-spherical shape. The functional groups present in the sample were identified using FTIR for TiO2 and TiO2/graphene nanocomposites. The stoichiometric ratios of all the constituent elements and the homogeneous composition were confirmed using EDX analysis. The UV–Vis spectroscopy revealed that the optical bandgap decreased from 3.15 eV to 2.80 eV. Additionally, the photocatalytic activity for the degradation of methylene blue (MB) under UV light was investigated. The photocatalytic performance was improved with increased graphene content. The evaluated data reveals that the sample with 10 % graphene has the maximum photocatalytic activity and rate constant. These findings suggest that gold-implanted TiO2/graphene nanocomposites favor photocatalytic applications and use in dye-sensitized solar cells.

Aggregate-Dominated Dilute Electrolytes with Low-Temperature-Resistant Ion-Conducting Channels for Highly Reversible Na Plating/Stripping.

Developing rechargeable batteries with high power delivery at low temperatures (LT) below 0°C is significant for cold-climate applications. Initial anode-free sodium metal batteries (AFSMBs) promise high LT performances because of the low de-solvation energy and smaller Stokes radius of Na+, nondiffusion-limited plating/stripping electrochemistry, and maximized energy density. However, the severe reduction in electrolyte ionic conductivity and formation of unstable solid electrolyte interphase (SEI) hinder their practical applications at LT. In this study, a 2-methyltetrahydrofuran-based dilute electrolyte is designed to concurrently achieve an anion-coordinated solvation structure and impressive ionic conductivity of 3.58mScm-1 at -40°C. The dominant aggregate solvates enable the formation of highly efficient and LT-resistant Na+ hopping channels in the electrolyte. Moreover, the methyl-regulated electronic structure in 2-methyltetrahydrofuran induces gradient decomposition toward an inorganic-organic bilayer SEI with high Na+ mobility, composition homogeneity, and mechanical robustness. As such, a record-high Coulombic efficiency beyond 99.9% is achieved even at -40°C. The as-constructed AFSMBs sustain 300 cycles with 80% capacity maintained, and a 0.5-Ah level pouch cell delivers 85% capacity over 180 cycles at -25°C. This study affords new insights into electrolyte formulation for fast ionic conduction and superior Na reversibility at ultralow temperatures.

Perovskite nanocrystals photo-initiated in situ encapsulation for optical tracking

Metal halide perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (MHP NCs) have been widely investigated for a variety of optoelectronic applications due to their superior photophysical characteristics. However, the inherent poor stability has limited broad applications. Herein, a facile in situ photopolymerization strategy using MHP NCs as photo-initiators is designed to fabricate homogeneous perovskite-silicone composites with outstanding stability, flexibility, and scalability. The fabrication process is completed upon exposure to 30 W ultraviolet light for 5 min under ambient conditions without additional protections and additives. The composites have exceptional stability in air and can even withstand harsh conditions, such as a basic pH of 13 for six months. The mechanical properties of composites are tunable from rigid to elastic by regulating the composition, ratios of polymerization monomers, and reaction time. Their superb properties enable optical visualization tracking for magnetically driven soft robots. This convenient and effective approach opens a new pathway for future applications in optical tracking, soft displays, biological detection, and bioimaging of perovskite nanocrystals.

Fundamental approach to superior trade-off between strength and ductility of TiB/Ti64 composites via additive manufacturing: From phase diagram to microstructural design

Reinforcement distribution tailoring has been proven effective in strengthening and toughening titanium matrix composites (TMCs). In this work, the analysis of the Ti64 (Ti-6Al-4V)-B phase diagram indicated that B content dominates the TiB distribution. With this philosophy, B content regulation was applied to tailor homogeneous and network structures in Ti64-B composites fabricated via laser-directed energy deposition additive manufacturing (AM). The unique plate-like TiB attends inhomogeneous composites (Ti64-0.05B). However, in network composite (Ti64-0.25B), the TiB whisker (TiBw) arranges along prior β-Ti grains with the same orientation. Moreover, the synergistic improvement of strength (988 MPa → 1202 MPa), stiffness (106 GPa → 116 GPa), hardness (325 HV → 362 HV), and uniform elongation (5 % → 7.8 %) were achieved. This work exhibited a balanced strength/ductility trade-off, which provides a good guide on microstructure tailoring.

How Professional Learning Networks Can Support Teachers’ Data Literacy: In Conversation with Experts

In the last decade data-based decision making has been promoted to stimulate school improvement and student learning. However, many teachers struggle with one or more elements of data-based decision making, as they are often not data literate. In this exploratory study, professional learning networks are presented as a way to provide access to data literacy that is not available in schools. Through interviews with scientific experts (n = 14), professional learning networks are shown to contribute to data-based decision making in four ways: (1) by regulating motivation and emotions throughout the process, (2) by encouraging cooperation by sharing different perspectives and experiences, (3) increasing collaboration to solve complex educational problems, and (4) encouraging both inward and outward brokering of knowledge. The experts interviewed have varying experiences on whether professional learning networks should have a homogenous and heterogenous composition, the degree of involvement of the school leaders, and which competencies a facilitator needs to facilitate the process of data-based decision making in a professional learning network.

Dammed coastal waterways are less diverse, more homogenous, and dominated by non-native species: Comprehensive insights from quantitative analysis of environmental DNA

Small dams are commonplace worldwide and impact local and regional aquatic diversity by altering habitats and disrupting dispersal networks. Quantifying the local and regional impacts of dams requires nearly comprehensive species occurrence data. We used environmental DNA (eDNA) metabarcoding to test theoretical predictions about the impacts of dams on local and regional bony fish diversity within the Chesapeake Bay Watershed, USA. We analyzed eDNA from 465 sampling points within 34 waterbodies documenting the distributions of 61 species. On average, dammed waterbodies had approximately half (48 %) as many species per site as undammed (lower alpha diversity) and more homogenous species composition (lower beta diversity). Native migratory species were less than one tenth (0.08) as likely to be detected at dammed sites than undammed sites, native resident (non-migratory) species were one third (0.34) as likely, whereas introduced species were 2.6 times more likely to be detected. Our sampling and bioinformatics methods were validated by a diverse mock community control. Our results suggest that dams in coastal waterways homogenize fish metacommunities, reduce local biodiversity through dispersal limitation and habitat alteration, and favor the dominance of lentic-adapted introduced species while potentially restricting the spread of introduced catfish. Decisions to construct or decommission dams should consider local and regional impacts on biodiversity.

Exploring novel magnetic behaviors in cobalt-doped magnetite synthesized by plasma arc discharge method

Magnetite, a naturally occurring iron oxide, has been widely studied due to its potential applications in various fields. Doping magnetite with foreign ions can significantly alter its structural and magnetic properties. This study aimed to investigate the effects of Co2+ ion doping on the structural and magnetic properties of magnetite. The work introduces cobalt-substituted iron ferrites synthesized using a novel plasma arc discharge (PAD) method and systematically explores how cobalt content affects magnetic properties, aiming to optimize the material for enhanced performance. A series of CoxFe1-xFe2O4 (x=0, 0.1, 0.2, 0.3, and 0.5) ferrites with varying Co2+ concentrations (x=0, 0.1, 0.2, 0.3, and 0.5) were synthesized using a PAD method. The synthesized materials were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Magnetic properties were evaluated through magnetic hysteresis loops and permeability spectra. XRD analysis confirmed the formation of a nanostructured spinel-type oxide in all samples. FESEM images revealed ultra-fine particles with a homogeneous composition and narrow size distribution. The optimal combination of magnetic properties was achieved at a Co2+ concentration of x=0.1, which exhibited a high saturation magnetization, low coercivity, moderate effective anisotropy constant, and a relatively high magnetic permeability at 5 MHz. The results demonstrate that Co2+ ion doping can effectively tailor the structural and magnetic properties of magnetite. The optimized composition (x=0.1) offers promising potential for applications requiring a balance of high magnetization and low coercivity.