Fabrication of Ag2S/CdS Heterostructured Nanosheets via Self-Limited Cation Exchange

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1295-1305 ◽  
Author(s):  
Charlotte Ruhmlieb ◽  
Angelique Rieckmann ◽  
Christian Strelow ◽  
Tobias Kipp ◽  
Alf Mews
Keyword(s):  
Cation Exchange ◽  
Three Dimensional ◽  
Solid Substrate ◽  
Second Step ◽  
Elementary Sulfur ◽  
Direct Reaction ◽  
X Ray Diffraction ◽  
Silver Surface ◽  
Large Area ◽  
Vertically Aligned

Abstract Highly crystalline vertically aligned Ag2S/CdS heterostructured nanosheets with lateral sizes of several micrometers and thicknesses of a few nanometers are prepared directly on silver surfaces by a two-step process. Firstly, Ag2S sheets were prepared by direct reaction of partially dissolved elementary sulfur in methanol with a solid silver surface in methanol at room temperature. The second step involves a self-limited cation exchange of Ag+ vs. Cd2+ to achieve the formation of large-area Ag2S/CdS heteronanosheets on the solid substrate. The cation exchange was proven and investigated over time via several analytical methods, e.g. X-ray diffraction, Raman spectroscopy and three-dimensional photoluminescence mapping.

Synthesis and Characterization of High Quality InN Nanowires and Nano-networks

2007 ◽  
Vol 1058 ◽  
Author(s):  
Zhihua Cai ◽  
Samir Garzon ◽  
Richard A. Webb ◽  
Goutam Koley
Keyword(s):  
Fast Rate ◽  
Three Dimensional ◽  
Catalyst Layer ◽  
Direct Reaction ◽  
Si Substrate ◽  
Large Area ◽  
High Quality ◽  
Dimensional Growth ◽  
Quartz Tube Furnace

ABSTRACTHigh quality InN nanowires have been synthesized in a horizontal quartz-tube furnace through direct reaction between metallic Indium and Ammonia using Nitrogen as the carrier gas. Thin film of Au on SiO2/Si substrate has been used as the catalyst layer, facilitating vapor-liquid-solid growth of the nanostructures. The nanowires were grown at a very fast rate of up to 30 μm/hr. Smooth and horizontal nanowire growth was achieved only with nanoscale catalyst patterns, while large area catalyst coverage resulted in uncontrolled and three-dimensional growth. The InN nanowires, which were usually covered with a thin shell layer of In2O3, grew along [110] direction, with overall diameters 20 - 60 nm and lengths 5 - 15 μm. The synthesized nanowires bent spontaneously or got deflected from other nanowires at multiples of 30 degrees forming nano-networks. The catalyst particles for the NWs were found mostly at the sides of the NW apex which helped them to bend spontaneously or get deflected from other NWs at angles which were multiples of 30 degrees. The NW based FETs with a back-gated configuration have already been investigated. The gate-bias dependent mobility of the NWs ranged from 55 cm2/Vs to 220 cm2/Vs, and their carrier concentration was ∼1018 cm−3.

scholarly journals Three-dimensional networks of superconducting NbSe2 flakes with nearly isotropic large upper critical field

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Togo Takahashi ◽  
Chisato Ando ◽  
Mitsufumi Saito ◽  
Yasumitsu Miyata ◽  
Yusuke Nakanishi ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Critical Field ◽  
Three Dimensional ◽  
Upper Critical Field ◽  
Synthetic Approach ◽  
X Ray Diffraction ◽  
Out Of Plane ◽  
Vertically Aligned ◽  
Superconducting Applications ◽  
Spin Momentum

AbstractIncreasing the upper critical field Hc2 in superconductors is one of the most significant requirements for superconducting applications. Two-dimensional (2D) noncentrosymmetric NbSe2 is a promising candidate because its pair breaking is protected by the spin-momentum locking effect, resulting in a giant in-plane Hc2 (~50 T). However, the strong anisotropy of 2D NbSe2 suppresses the robustness of out-of-plane Hc2 (<5 T). To overcome this issue, we propose a synthetic approach to produce superconducting NbSe2 films with a nearly isotropic large Hc2. Scalable selenization methods are tailored to create 3D superconducting networks in which 2D NbSe2 flakes are vertically aligned to the substrates. The angle-resolved magneto-transports reveal enhanced Hc2 values that exceed 20 T for arbitrary directions under externally applied magnetic fields. The isotropic nature of Hc2 is attributed to the averaging intrinsic anisotropy of NbSe2 through 3D structured films, which was determined by X-ray diffraction measurements. The proposed synthetic approach will provide a new method for creating practical superconductors that are robust against magnetic fields.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Electron Microscopy of Cytoplasmic Contractile Proteins

1978 ◽  
Vol 36 (3) ◽  
pp. 606-614 ◽  
Author(s):  
T.D. Pollard ◽  
P. Maupin
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Uranyl Acetate ◽  
Contractile Proteins ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Cytoplasmic Matrix ◽  
Computer Image Processing ◽  
Nonmuscle Cells

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

scholarly journals Mastering of NIL Stamps with Undercut T-Shaped Features from Single Layer to Multilayer Stamps

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 956
Author(s):  
Philipp Taus ◽  
Adrian Prinz ◽  
Heinz D. Wanzenboeck ◽  
Patrick Schuller ◽  
Anton Tsenov ◽  
...  
Keyword(s):  
Electron Beam Lithography ◽  
Nanoimprint Lithography ◽  
Silicon Oxide ◽  
Three Dimensional ◽  
Single Layer ◽  
Fabrication Technology ◽  
Large Area ◽  
Structural Colors ◽  
Biomimetic Structures ◽  
Morpho Butterfly

Biomimetic structures such as structural colors demand a fabrication technology of complex three-dimensional nanostructures on large areas. Nanoimprint lithography (NIL) is capable of large area replication of three-dimensional structures, but the master stamp fabrication is often a bottleneck. We have demonstrated different approaches allowing for the generation of sophisticated undercut T-shaped masters for NIL replication. With a layer-stack of phase transition material (PTM) on poly-Si, we have demonstrated the successful fabrication of a single layer undercut T-shaped structure. With a multilayer-stack of silicon oxide on silicon, we have shown the successful fabrication of a multilayer undercut T-shaped structures. For patterning optical lithography, electron beam lithography and nanoimprint lithography have been compared and have yielded structures from 10 µm down to 300 nm. The multilayer undercut T-shaped structures closely resemble the geometry of the surface of a Morpho butterfly, and may be used in future to replicate structural colors on artificial surfaces.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

scholarly journals Synthesis and Compressibility of Novel Nickel Carbide at Pressures of Earth’s Outer Core

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 516
Author(s):  
Timofey Fedotenko ◽  
Saiana Khandarkhaeva ◽  
Leonid Dubrovinsky ◽  
Konstantin Glazyrin ◽  
Pavel Sedmak ◽  
...  
Keyword(s):  
Equation Of State ◽  
Outer Core ◽  
Direct Reaction ◽  
Volume Data ◽  
X Ray Diffraction ◽  
Nickel Carbide ◽  
Diamond Anvils ◽  
Group A ◽  
Diamond Anvil ◽  
Murnaghan Equation

We report the high-pressure synthesis and the equation of state (EOS) of a novel nickel carbide (Ni3C). It was synthesized in a diamond anvil cell at 184(5) GPa through a direct reaction of a nickel powder with carbon from the diamond anvils upon heating at 3500 (200) K. Ni3C has the cementite-type structure (Pnma space group, a = 4.519(2) Å, b = 5.801(2) Å, c = 4.009(3) Å), which was solved and refined based on in-situ synchrotron single-crystal X-ray diffraction. The pressure-volume data of Ni3C was obtained on decompression at room temperature and fitted to the 3rd order Burch-Murnaghan equation of state with the following parameters: V0 = 147.7(8) Å3, K0 = 157(10) GPa, and K0' = 7.8(6). Our results contribute to the understanding of the phase composition and properties of Earth’s outer core.

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