Investigation of W-Ge-N deposited on Ge as a diffusion barrier for Cu metallization

The properties of W-Ge-Nthin films were investigated as a diffusion barrier material for Cu metallization. The W-Ge-Nfilms were grown by reactive sputtering on a single crystal Ge substrate. This was followed by in-situ deposition of Cu. Diffusion barrier test was performed by annealing the film stack under Ar atmosphere. Phase identification and film crystallization were determined by X-ray diffraction. The deposited W-Ge-Nfilms remained amorphous even after high temperature annealing. The Cu diffusion profile in the film was assessed by Auger electron spectroscopy and energy dispersive spectroscopy. The results indicate that Cu diffusion was minimal in W-Ge-Nfilms even at high annealing temperatures. Interface reactions and properties were analyzed by cross-section transmission electron microscopy. The results suggest that W-Ge-Nmay be a superior diffusion barrier as compared to WN_x for Cu metallization. PACS 66.30.Ny; 68.35.Rh; 68.37.Lp; 68.60.Dv     

Repurposing the antibacterial drugs for inhibition of SARS-CoV2-PLpro using molecular docking,MD simulation and binding energy calculation

Molecular Diversity - Papain-like protease (nsp-3; non-structural protein) of novel corona virus is an ideal target for developing drugs as it plays multiple important functions for viral growth...     

Study of Anticancer Properties of Graphene Oxide–Metal Oxide Composite

Graphene and graphene oxide (GO) have garnered significant attention due to their exceptional properties. GO, enriched with various functional groups such as epoxy, hydroxyl, and carboxylic groups, has exhibited remarkable potential in biomedical applications. The combination of GO with metals has proven to be a promising platform for cellular imaging, with this study focusing on the preparation of diverse hybrids of GO with metal oxides (GO/MO) and their potential as anticancer agents. In this research, GO is functionalized with MOs like TiO₂, Fe₃O₄, and Cu₂O using specific chemical methods and investigated for the anticancer activity for the application as cancer therapeutic agent. The resulting GO/MO hybrids exhibits favorable thermal and mechanical properties. Moreover, their cytotoxicity against human lung cancer cells is assessed in vitro, revealing the promising anticancer activity of GO/MO hybrids. Notably, the GO/Cu₂O hybrid demonstrates particularly high cytotoxicity in human lung cancer cells.     

Measurement of nonlinear damping in a Gr/Al metal-matrix composite

This paper is concerned with the measurement of nonlinear (i.e., strain amplitude dependent) intrinsic material damping in continuous-fiber-reinforced metal-matrix composites (MMC). The particular MMC studied is a four-ply [±θ] _s P55Gr/6061 Al composite with θ=0, 15, 30, 45, 60, 75 deg. A popular method for measuring damping is the free-decay of flexural vibrations of a cantilevered beam. However, the strain field in a cantilevered beam is inhomogeneous. Therefore, for materials whose damping is nonlinear, the measured specimen damping is not equal to the intrinsic material damping. Using an elementary algorithm develeped by Lazan, the authors extract nonlinear intrinsic material damping from the nonlinear specimen damping.     

Understanding and controlling organic-inorganic interfaces in mesostructured hybrid photovoltaic materials

The chemical compositions and structures of organic-inorganic interfaces in mesostructurally ordered conjugated polymer-titania nanocomposites are shown to have a predominant influence on their photovoltaic properties. Such interfaces can be controlled by using surfactant structure-directing agents (SDAs) with different architectures and molecular weights to promote contact between the highly hydrophobic electron-donating conjugated polymer species and hydrophilic electron-accepting titania frameworks. A combination of small-angle X-ray scattering (SAXS), scanning and transmission electron microscopy (SEM, TEM), and solid-state NMR spectroscopy yields insights on the compositions, structures, and distributions of inorganic and organic species within the materials over multiple length scales. Two-dimensional NMR analyses establish the molecular-level interactions between the different SDA blocks, the conjugated polymer, and the titania framework, which are correlated with steady-state and time-resolved photoluminescence measurements of the photoexcitation dynamics of the conjugated polymer and macroscopic photocurrent generation in photovoltaic devices. Molecular understanding of the compositions and chemical interactions at organic-inorganic interfaces are shown to enable the design, synthesis, and control of the photovoltaic properties of hybrid functional materials.     

Studies toward the asymmetric synthesis of the right part of the mycalamides

Described herein is the asymmetric synthesis of a functionalized, trioxadecalin unit that comprises the right-hand part of the mycalamides and related natural products. The synthetic route involves a 16-step sequence that accomplishes the formation of two heterocyclic rings and the generation of five stereocenters. The synthesis commenced with a C2-symmetric starting material, diethyl D-tartrate, and took advantage of a relay of diastereoselective reactions to extend this four-carbon chain and introduce new chiral centers. Subsequent electrophile-mediated cyclization afforded the desired pyran ring, which was then transformed into the desired, functionalized trioxadecalin skeleton.     

Design parameters for a robust superhydrophobic electrospun nonwoven mat

Electrospun nonwoven mats exhibiting extreme hydrophobicity have recently attracted much attention for their use in a wide range of applications. These materials are highly heterogeneous and irregular in structure, and accordingly, the design parameters of such materials need to be carefully chosen for obtaining higher apparent contact angles along with the robust composite solid-liquid-vapor interface. Here, we present two dimensionless design parameters, namely, the spacing ratio and pressure difference across the liquid-vapor interface, for enhancing the stability of the Cassie regime. These design parameters are essentially dependent upon the structural characteristics of the electrospun mat and equilibrium contact angle of the liquid. Interestingly, the stability of the composite interface is a trade-off between these dimensionless parameters. Moreover, the pressure difference across the interface can significantly increase by reducing the fiber diameter to nanoscale. The stability of the Cassie state in an electrospun nonwoven mat consisting of lower fiber volume fractions at the nanostructural scale can restore superhydrophobicity even after the impact of a rainfall.     

Total synthesis of (+/-)-bipinnatin J

[reaction: see text]. The total synthesis of (+/-)-bipinnatin J was achieved through a concise route that features the use of a silver ion promoted S(N)1-type gamma-alkylation of a siloxyfuran and a diastereoselective Cr(II)-mediated macrocyclization to provide bipinnatin J (1), wherein the remote furanone stereocenter at C10 induced the relative stereochemistry of the two additional stereocenters.     

Silver-catalyzed formal inverse electron-demand Diels-Alder reaction of 1,2-diazines and siloxy alkynes

A highly effective silver-catalyzed formal inverse electron-demand Diels-Alder reaction of 1,2-diazines and siloxy alkynes has been developed. The reactions provide ready access to a wide range of siloxy naphthalenes and anthracenes, which are formed in good to high yields, under mild reaction conditions, using low catalyst loadings.