Narrow Edge Research Articles

An Infrequent 1D Manganese-Tin Selenide with Bifunctional Catalytic Properties.

The optoelectronic, electrocatalytic, and photocatalytic properties of new tin selenides are of great significance for various energy applications. Herein, a facile solvothermal reaction of Sn, Se, and MnCl2 in 1,3-propodiamine (1,3-dap) solution at 150 °C for 7 days was used to achieve a new type of one-dimensional (1D) organic hybrid manganese-tin selenide [Mn2(1,3-dap)4(μ-1,3-dap)Sn2Se6]n (MnSnSe-1), whose 1D framework is built up from the linkage of rare unsaturated binuclear [Mn2(1,3-dap)4(μ-1,3-dap)]2+ cations and dimeric [Sn2Se6]4- anions. The combination of MnSnSe-1 and Ni nanoparticle is first applied for the preparation of a Ni/MnSnSe-1/NF electrode (NF = porous Ni foam) as the efficient electrocatalyst for the hydrogen evolution reaction (HER), indicating excellent HER electrocatalytic property with an overpotential of 117 mV at 10 mA·cm-2 in a neutral medium. Owing to its narrow absorption edge of 1.65 eV, implying prominent harvesting ability in the visible-light region, MnSnSe-1 shows a remarkable photocurrent response and excellent visible-light-driven photocatalytic property for the degradation of methylene blue in aqueous solution.

Meandering conduction channels and the tunable nature of quantized charge transport

The discovery of the quantum Hall effect has established the foundation of the field of topological condensed matter physics. An amazingly accurate quantization of the Hall conductance, now enshrined in quantum metrology, is stable against any reasonable perturbation due to its topological protection. Conversely, the latter implies a form of censorship by concealing any local information from the observer. The spatial distribution of the current in a quantum Hall system is such a piece of information, which, thanks to spectacular recent advances, has now become accessible to experimental probes. It is an old question whether the original and intuitively compelling theoretical picture of the current, flowing in a narrow channel along the sample edge, is the physically correct one. Motivated by recent experiments locally imaging quantized current in a Chern insulator (Bi, Sb)[Formula: see text]Te[Formula: see text] heterostructure [Rosen et al., Phys. Rev. Lett. 129, 246602 (2022); Ferguson et al., Nat. Mater. 22, 1100-1105 (2023)], we theoretically demonstrate the possibility of a broad "edge state" generically meandering away from the sample boundary deep into the bulk. Further, we show that by varying experimental parameters one can continuously tune between the regimes with narrow edge states and meandering channels, all the way to the charge transport occurring primarily within the bulk. This accounts for various features observed in, and differing between, experiments. Overall, our findings underscore the robustness of topological condensed matter physics, but also unveil the phenomenological richness, hidden until recently by the topological censorship-most of which, we believe, remains to be discovered.

Transforming the rhetoric of Just Energy Transition Partnerships into reality: The devil lies in the details

Urgent political action is required to arrest the rise in global temperature within the 1.5°C target of the Paris Agreement. Rising to this challenge, a series of Just Transition Energy Partnerships (JETPs) was launched between individual Global South and a group of Global North countries since COP 26 in Glasgow. Germany, France, the United Kingdom, the United States, and the European Union (International Partner Group or IPG countries) have established plurilateral partnerships with individual countries like South Africa, Vietnam, Indonesia, and Senegal in each JETP. These partnerships aim to help IPG countries provide long-term support to partner countries in the Global South to disengage from coal and convert to renewables for electricity generation. However, though ’just transitions’ and ’partnerships’ are potent ideas to drive such processes, it is challenging to translate these ideas from political rhetoric to policies. This paper argues that JETPs are treading on a narrow edge with a high chance of re-instantiating some of the criticism of partnerships between Global North and Global South countries that can detrimentally affect the chances of just transition. Based on academic literature on partnerships and just transition, the paper concludes that the devil lies in the details. Formalizing processes that deliver a just and fair energy transition should align with the Global South countries’ social, economic, and political realities.

Comparison of edge effects from well pads and industrial roads on mixed upland boreal forest vegetation in Alberta

AbstractThe industrial footprint of oil and gas extraction in Alberta, Canada dissects the landscape in a network of linear and polygonal disturbances such as roads and well pads. The changes to biotic and abiotic factors beyond the boundaries of these disturbances into the adjacent ecosystem are called edge effects. A common assumption is that edge effects are proportional to the width of the disturbance, with wider disturbances leading to deeper effects into the forest. The objective of this study is to compare edge effects on plant composition, seed dispersal distance, seed weight, and microclimate across three disturbance types: narrow (< 20 m) and wide (> 20 m) roads, and well pads (> 100 m; 1.9 ha) in upland boreal forests in the oil sands region of north-eastern Alberta. We sampled 1 m2 plots at six distances (0 m, 10 m, 15 m, 25 m, 50 m, and 75 m) along transects running perpendicular from the disturbance edge into the forest. Edge effects for plant communities were contained at the disturbance edge for all disturbance types considered. Understory species richness was lower at the disturbance edge and was dominated by introduced species and species with lighter seeds and with medium-distance dispersal mechanisms. Disturbance edges were characterized as having higher soil moisture content, higher soil temperature, and a thinner organic matter layer compared to the forest interior (> 10 m). With no effect of disturbance width on width of edge effects, our study does not support the assumption that narrower disturbances will necessarily result in narrower edge effects for vegetation and abiotic metrics.

Effects of the Growth Facet Shape of Self‐Catalyzed GaAs Nanowires on the Zinc‐Blende–Wurtzite Switching

Herein, the crystal phase switching between the cubic zinc‐blende and hexagonal wurtzite phases in self‐catalyzed GaAs nanowires (NWs) is theoretically studied, considering the dependence of the droplet contact angle on the position at the triple‐phase line. This dependence is calculated for the droplets resting on the NW top facet, which has the shape of truncated hexagon. The nucleation of c and h islands, corresponding to the cubic and hexagonal crystal phases, at the triple‐phase line and in the center of the catalyst–NW interface, is considered within the classical nucleation theory. As a result, the probability of h‐island nucleation as a function of the average contact angle is obtained. It is found that the maximum of this probability shifts to the region of large contact angles when the length of narrow edges of the NW top facet decreases. Also, it is shown that the GaAs island nucleation at the triple‐phase line occurs preferentially in the vicinity of the top facet corners.

High gain narrow wall standing wave slotted waveguide antenna with flanges

ABSTRACT In this study, narrow (edge) wall standing wave slotted waveguide antenna design is proposed. This antenna operates at 2.812 GHz in S frequency band. Also, the design equations and slot characterization method are given in this study. This antenna is designed with two flanges to shape the elevation pattern and to increase the antenna gain. This antenna provides low cross polarization without using any polarizer or any other structure. The designed antenna is suitable for high gain and high-power applications. The performance of the proposed design is examined with simulations and verified with measurements.

Reactivity-matched synthesis of monodisperse Ag(In,Ga)S2 QDs with efficient luminescence.

I-III-VI quantum dots (QDs) have gained widespread attention owing to their significant advantages of non-toxicity, large structural tolerance, and efficient photoluminescence potential. However, the disbalance of reactivity between the elements will result in undesired products and compromised optical properties. Reducing the activity of highly reactive group IB elements is the most common approach, but it will reduce the overall reactivity and lead to a wide dispersion of QD sizes. In this study, we propose a method to improve the overall reactivity of the reaction system using the highly active IIIA precursor InI3, which triggers rapid nucleation and promotes the formation of Ag(In,Ga)S2 (AIGS) QDs, resulting in monodisperse particle size distributions and a significantly improved photoluminescence quantum yield (PLQY) (from 12% to 72%). Furthermore, narrow band edge emission is realized by coating a gallium sulfide (GaSx) shell on the basis of obtaining high-quality AIGS QDs. The core/shell QDs exhibit a 90% PLQY with a full width at half maximum (FWHM) of only 31 nm at 530 nm. This study provides a viable design strategy to synthesize monodisperse AIGS QDs with a narrow peak width and efficient luminescence, promoting the application of AIGS QDs in the field of luminescent displays.

Construction of coumarin-appended calix[4]arene-based fluorescence sensor for the detection of carbofuran in cabbage.

This study presents a novel approach for the detection of carbofuran (CBF) insecticide by systematically exploring a calix[4]arene-derived fluorescence probe, CouC4S, functionalized with two coumarin-labelled cystamine linkages at the narrow edge of the calix[4]arene platform. The proposed method showed a fluorescence "signal - off" effect when CBF binds with CouC4S by quenching the fluorescence intensity of CouC4S. Its limit of detection was as low as 5.55 μM according to the emission study. The working concentration range for this ligand was observed to be up to 5-65 μM. This method could be applied for the on-spot detection of CBF in real samples such as cabbage by spiking CBFvia in situ experiments, which exhibited a limit of detection of 8.823 ppm. For the further confirmation of CouC4S:CBF binding, cyclic voltammetry, differential pulse voltammetry, powder X-ray diffraction, FT-IR spectroscopy, 1H NMR titration, MALDI-TOF and computational investigations were carried out.

Cdc42 activity in the trailing edge is required for persistent directional migration of keratinocytes.

Fibroblasts migrate discontinuously by generating transient leading-edge protrusions and irregular, abrupt retractions of a narrow trailing edge. In contrast, keratinocytes migrate persistently and directionally via a single, stable, broad protrusion paired with a stable trailing-edge. The Rho GTPases Rac1, Cdc42 and RhoA are key regulators of cell protrusions and retractions. However, how these molecules mediate cell-type specific migration modes is still poorly understood. In fibroblasts, all three Rho proteins are active at the leading edge, suggesting short-range coordination of protrusive Rac1 and Cdc42 signals with RhoA retraction signals. Here, we show that Cdc42 was surprisingly active in the trailing-edge of migrating keratinocytes. Elevated Cdc42 activity colocalized with the effectors MRCK and N-WASP suggesting that Cdc42 controls both myosin activation and actin polymerization in the back. Indeed, Cdc42 was required to maintain the highly dynamic contractile acto-myosin retrograde flow at the trailing edge of keratinocytes, and its depletion induced ectopic protrusions in the back, leading to decreased migration directionality. These findings suggest that Cdc42 is required to stabilize the dynamic cytoskeletal polarization in keratinocytes, to enable persistent, directional migration.

TiO2@TiOx homojunction photocatalyst: Self-doped preparation and superior photocatalytic hydrogen evolution and dye degradation

So far, there still existed many challenges on the effective utilization of solar energy and rapid transportation of photo-generated carrier in the photocatalysis fields. The constructing structural/functional configuration of photocatalyst by combining the homojunctions with oxygen vacancies (Ov) was a good project to overcome these inherent disadvantages. Herein, the homogeneous TiO2@TiOX photocatalysts were designed and fabricated by a solid-phase thermal reduction technology using sodium borohydride as a reducing agent. The structure, morphology, chemical binding, active species and photo-electrochemical properties of the TiO2@TiOX were sufficiently investigated via various characterization techniques and indicated that the high-quality homojunction at the TiO2-TiOX interface and abundant oxygen vacancies on the surface was formed. The photocatalytic degradation and H2 production experiment showed that the constructed TiO2@TiOX exhibited more outstanding photocatalytic performances, which was 1.4 times higher and 2 times higher than that of the Raw TiO2, respectively. The photocatalytic mechanism was proposed that the synergistic effect of optical and electrical properties of TiO2@TiOX, such as narrow gap edge and significant enhancement in conductivity, greatly strengthened the photo-response, expanded the response range of spectrum, enhanced photocarriers migration and the photocatalytic activity. This work could provide new opportunity into the design of novel structures of photocatalyst for more efficient light conversion applications.

Stray magnetic fields from elliptical-shaped and stadium-shaped ferromagnets

An artificial spin ice consisting of numerous ferromagnets has attracted attention because of its applicability to practical devices. The ferromagnets interact through their stray magnetic field and show various functionality. The ferromagnetic element in the spin ice was recently made in elliptical-shape or stadium-shape. The former has a narrow edge, expecting to generate a large stray magnetic field. The latter has a large volume and is also expected to generate a large stray magnetic field. Here, we estimate the stray magnetic field by numerically integrating the solution of the Poisson equation. When magnetization is parallel to an easy axis, the elliptical-shaped ferromagnet generates a larger stray magnetic field than the stadium-shaped ferromagnet. The stray magnetic fields from both ferromagnets for arbitrary magnetization directions are also investigated.

High optical spin-filtering in antiferromagnetic stanene nanoribbons induced by band bending and uniaxial strain

Non-equilibrium spin-polarized transport properties of antiferromagnetic stanene nanoribbons are theoretically studied under the combining effect of a normal electric field and linearly polarized irradiation based on the tight-binding model at room temperature. Due to the existence of spin-orbit coupling in stanene lattice, applying normal electric field leads to splitting of band degeneracy of spin-resolved energy levels in conduction and valence bands. Furthermore, unequivalent absorption of the polarized photons at two valleys which is attributed to an antiferromagnetic exchange field results in unequal spin-polarized photocurrent for spin-up and spin-down components. Interestingly, in the presence of band bending which has been induced by edge potentials, an allowable quantum efficiency occurs over a wider wavelength region of the incident light. It is especially important that the variation of an exchange magnetic field generates spin semi-conducting behavior in the bended band structure. Moreover, it is shown that optical spin-filtering effect is obtained under the simultaneous effect of uniaxial strain and narrow edge potential.

Quasi-one-dimensional bulk thermoelectrics

In a recent Science Bulletin article, Dong et al. reported a quasi-one-dimensional TlCu3Te2 bulk material with an application-level room temperature ZT of 1.3 benefited from the pancake-like Fermi pocket with quasi-one-dimensional dispersion at narrow band-gap edge and the large, anharmonic quasi-one-dimensional lattice of heavy Tl+ and weakly bonded Cu+ ions. In a recent Science Bulletin article, Dong et al. reported a quasi-one-dimensional TlCu3Te2 bulk material with an application-level room temperature ZT of 1.3 benefited from the pancake-like Fermi pocket with quasi-one-dimensional dispersion at narrow band-gap edge and the large, anharmonic quasi-one-dimensional lattice of heavy Tl+ and weakly bonded Cu+ ions.

A new J.E probe for measurement of spatial profiles of power absorption in RF produced plasma.

This paper reports an indigenously developed probe for the measurement of spatial profiles of the absorbed/generated RF power density Pabs (W/m3) in RF discharges. The technique utilizes a calibrated current (J) probe based on the Rogowski coil principle and an electric field (E) probe based on capacitive coupling, both integrated into a single probe called the J.E probe. Various aspects of the probe, such as its design, fabrication, calibration, and limitations, were resolved before it was used for obtaining axial profiles of RF power absorption/generation. Also presented are the first experimental results for the absorbed power density profiles at the fundamental (13.56MHz) and harmonic (27.12MHz) along the length of a capacitively coupled discharge. The axial scans between the powered and grounded electrode were taken at different argon gas pressures (10-800mTorr) at a fixed RF power of 10W. Detailed analysis of the results shows that even for systems with large electrode gaps, i.e., plasmas with long bulk plasma regions, practically all the fundamental power is absorbed in a narrow edge region near the powered electrode, irrespective of the pressure. Absorption is high near the RF electrode since the RF fields peak in this region. Another important conclusion is that stochastic absorption of the fundamental and harmonic generation proceeds fairly efficiently in the vicinity of the powered electrode even at high pressures. It may be mentioned that the probe technique introduced here is the first of its kind, and although there is considerable scope for miniaturization, it has, nonetheless, provided some key insights into the nature of RF power absorption in capacitive discharges.

Theoretical Insights on the Complexation of Americium(III) and Europium(III) with Diglycolamide- and Dimethylacetamide-Functionalized Calix[4]arenes

Separation of minor actinides from lanthanides is one of the biggest challenges in spent fuel reprocessing due to the similar physicochemical properties of trivalent lanthanides (Ln(III)) and actinides (An(III)). Therefore, developing ligands with excellent extraction and separation performance is essential at present. As an excellent pre-organization platform, calixarene has received more attention on Ln(III)/An(III) separation. In this work, we systematically explored the complexation behaviors of the diglycolamide (DGA)/dimethylacetamide (DMA)-functionalized calix[4]arene extractants for Eu(III) and Am(III) using relativistic density functional theory (DFT). These calix[4]arene-derived ligands were obtained by functionalization with two or four binding units at the narrow edge of the calix[4]arene platform. All bonding nature analyses suggested that the Eu-L complexes possess stronger interaction compared to Am-L analogues, resulting in the higher extraction capacity of the these calix[4]arene ligands toward Eu(III). Thermodynamic analysis demonstrates that these pre-organized ligands on the calix[4]arene platform with four binding units yield better extraction abilities than the single ligands. Although DMA-functionalized ligands show stronger complexation stability for metal ions, in acidic solutions, the calix[4]arene ligands with DGA binding units have better extraction performance for Eu(III) and Am(III) due to the basicity of the DMA ligand. This work enabled us to gain a deeper understanding of the bonding properties between supramolecular ligands and lanthanides/actinides and afford useful insights into designing efficient supramolecular ligands for separating Ln(III)/An(III).

Revision of the edge channel picture for the integer quantum Hall effect

State of the art computing opens now a new window to the integer quantum Hall effect (IQHE) regime, which enforces a major revision of the common knowledge accumulated so far. In our record-breaking application of the Hartree–Fock method we use up to 3000 electrons distributed over up to 5000 states for almost macroscopic system size of 1000 × 1000 nm. In particular, the formation of compressible and in-compressible edge stripes turns out to develop essentially different from the common picture used so far. Oppositely to the theory of Chklovskii, Shklovskii and Glazman (CSG), the narrow channels, as assumed by the early models of the IQHE, do not widen up into wide compressible stripes. Instead, the wide compressible stripes of CSG transform into a mixture of clusters of full and empty spin-split LLs, while the cluster boundaries create a network of still narrow quantum channels sitting on top of the wide compressible stripes. On this background the early models based on narrow edge channels do not suffer from neglecting electron–electron interaction as falsely stated in the past. Quite oppositely, in contrast to the common believe, our modeling demonstrates that also the IQHE regime carries the hallmark of many-body physics which stabilizes narrow edge channels also in the presence of electron–electron interaction.

Effect of different blister positions on void fraction distribution under subcooled boiling conditions in narrow rectangular channel

Cladding blistering of plate fuel element is one of the common accidents in the operation of research reactor. At present, there was little research on coolant flow boiling under blister conditions. However, the void fraction distribution of coolant under boiling condition was closely related to CHF. To study the effect of a blister on the void fraction under subcooled boiling, a numerical method was used to simulate the blister phenomenon in the narrow rectangular channel. The Euler two fluid model was adopted in this study and the modified RPI model was used to simulate flow boiling. The calculation results showed that a blister on the heating surface could lead to a significant change in the void fraction distribution near the blister area. The distribution trend of the void fraction in the rear of the blister was different under different axial blister position conditions. In general, the closer the axial position of the blister was to the outlet of the channel and the closer the lateral position was to the narrow edge of the narrow rectangular channel, and the larger the peak value of the local void fraction was. The local maximum of the void fraction could rise to over 0.8, and heat transfer deterioration may occur in the blister area.

Uranus ring occultation observations: 1977–2006

The Uranian rings were discovered serendipitously on 10 March 1977 during a stellar occultation (Elliot et al., 1977a; Millis et al., 1977), and a rich set of subsequent Earth-based occultations revealed that these narrow and sharp-edged rings were eccentric and inclined, precessing under the gravitational influence of the oblate central planet. Considerable progress has been made in understanding the observed characteristics of narrow rings and sharp edges (Nicholson et al., 2018) and their associated dynamics (Longaretti, 2018), but ever since their discovery, the Uranian rings have posed dynamical puzzles that resist simple explanations. The observational basis to address these questions for the Uranus system rests largely on occultation measurements of the narrow rings spanning nearly 30 years, beginning in 1977 and concluding most recently in 2006. Nearly all of these occultation data sets are available in digital form on NASA’s Planetary Data System (PDS) Ring-Moon Systems node, but many of them have not been previously published or described in detail. This paper serves as a guide to the PDS archive and provides essential information about the observations and the methods used to determine the ring widths, mean optical depths, and occultation event times from individual occultation profiles. Additional detail is provided in the Supplementary Online Material accompanying this publication. In a companion paper (French et al., 2023b), we make use of these observations to determine the Uranus ring orbits, pole direction, and gravity field, and the orbital characteristics and masses of three small Uranian moons – Cressida, Ophelia, and Cordelia – from their forced normal modes on the rings.

“The Narrow edge of the wedge?” Assessing the Legality of the Killing of Qasem Soleimani in International Law

“The Narrow edge of the wedge?” Assessing the Legality of the Killing of Qasem Soleimani in International Law

Становление культуры делопроизводства в России XIV – начала XVI века

Introduction. Writing, as a special sign system, provides a link between the past and the present is one of the main ways of transmitting cultural tradition. This article deals with a special form of clerical work in Medieval Russia – scrolls and columns. Materials. A column with a border is a narrow strip of paper, about 16– 17 cm wide and up to 45 cm long, or 14–15 cm wide and up to 35 cm long. They were glued together along a narrow edge with each other, resulting in documents up to several tens of meters long – columns. Such documents were kept twisted, in scrolls. Analysis. In the second half of the 15th century, the Grand ducal chancery became the center of administrative power. There were a transformation and development of clerical work in it. The conducted research suggests that the appearance of the column form of clerical work was due to political, socio-economic and cultural reasons. The appearance of the columns dates back to the second half of the 15th century. The disappearance of the column form of clerical work occurred in 1700–1702. Peter I initiated a revolution in clerical work by ordering to switch to conducting business in a notebook form. The innovation did not spread immediately; the old traditions of document processing were preserved in the monasteries for several years. Results. The appearance of the columnar form of clerical work coincided with the emergence of a single centralized state under Ivan III, the increasing importance of the clerical apparatus. The disappearance was due to the reforms of Peter I, the formation of the Russian Empire and the replacement of orders by colleges. It is obvious that the emergence and disappearance of such a specific form of office work are associated with large-scale national changes.