1988 articles

69 publishers

Join mailing list

Dec 2022 • Advanced Electronic Materials

One‐Pot Synthesis of Deep Blue Hydrophobic Carbon Dots with Room Temperature Phosphorescence, White Light Emission, and Explosive Sensor

Sudhakar Pagidi, Hari Krishna Sadhanala, Kusha Sharma, Aharon Gedanken

Bright luminescent hydrophobic carbon dots receive significant attention on account of their potential utility in bio‐imaging, sensors, and creating a full range of colors in displays. Herein, the solvothermal one‐pot synthesis of nitrogen and sulfur‐doped hydrophobic carbon dots (HCDs) from a single precursor, is reported. These HCDs exhibit good dispersibility in different organic solvents and show blue fluorescence in solid and solution states. Notably, HCDs show green color room temperature phosphorescence emission centered at 515 nm with a long average lifetime of 1.1 ms and an ultralong lifetime of 334 ms at 77 K. An intense white light with Commission international de d'Eclairage chromaticity coordinate of (0.32, 0.34) is generated by a simple mixing of HCDs with rhodamine 6G in the solution state. Furthermore, these HCDs are explored for the rapid detection of extremely hazardous and strong explosive …

Show more

Dec 2022 • Journal of The Electrochemical Society

An Improved Cycling Performance of Different Types of Composite Sulfur-Carbon Cathodes with the Use of Lithium Polysulfides Containing Electrolyte Solutions

Elena Markevich, Gregory Salitra, Hideki Yoshida, Shunsuke Sawada, Doron Aurbach

We report on stabilization of Li-S cells with different types of composite sulfur cathodes using ethereal LiTFSI/LiNO3/DOL/DME electrolyte solutions containing a-priori 0.1M Li2S8. These electrolyte solutions enable an improved cycling behavior for Li-S cells compared to Li2S8-free electrolyte solutions, thanks to the presence of LiSx species from the beginning of operation. We show that Li anodes cycled in Li|S cells with solutions containing Li2S8 possess flatter and more uniform surface, higher dimensions of the surface structures in average and, as a result, a lower surface area. This surface morphology ensures a low rate of parasitic surface reactions of the electrolyte components on the Li anodes’ surface, slower depletion of the electrolyte solution in the cells and stabilization of the cells cycling. Besides, the presence of Li2S8 maintains a better integrity of composite sulfur/carbon/PVdF cathodes, ensuring a …

Show more

Dec 2022 • Materials Today Energy

Ionically selective carbon nanotubes for hydrogen electrocatalysis in the hydrogen–bromine redox flow battery

Samuel S Hardisty, Kobby Saadi, Samala Nagaprasad Reddy, Ilya Grinberg, David Zitoun

Catalyst poisoning and leaching is a problem faced in almost all catalyst applications. A specific technology where catalyst poisoning and leaching are a major concern is the hydrogen bromine redox flow battery (H 2-B r 2 RFB), one of the most promising energy storage technologies. However, it is currently hindered through degradation of the hydrogen oxidation/evolution catalyst, caused by B r-/B r 3-which have crossed the membrane. To prevent this degradation, Pt nanoparticles were synthesized inside 2 nm single-walled carbon nanotubes (SWCNTs). Electrochemical and spectroscopic techniques show that the Pt@ SWCNT has a vastly improved stability and higher mass activity over a commercial 50% Pt/C catalyst. Density functional theory (DFT) calculations show that the stability results from the selective diffusion of H 2 and H+ over the B r-and B r 3-species through the SWCNT to the Pt catalyst, effectively …

Show more

Dec 2022 • Genome medicine

T cell receptor beta germline variability is revealed by inference from repertoire data

Aviv Omer, Ayelet Peres, Oscar L Rodriguez, Corey T Watson, William Lees, Pazit Polak, Andrew M Collins, Gur Yaari

T and B cell receptor (TCR, BCR) repertoires constitute the foundation of adaptive immunity. Adaptive immune receptor repertoire sequencing (AIRR-seq) is a common approach to study immune system dynamics. Understanding the genetic factors influencing the composition and dynamics of these repertoires is of major scientific and clinical importance. The chromosomal loci encoding for the variable regions of TCRs and BCRs are challenging to decipher due to repetitive elements and undocumented structural variants. To confront this challenge, AIRR-seq-based methods have recently been developed for B cells, enabling genotype and haplotype inference and discovery of undocumented alleles. However, this approach relies on complete coverage of the receptors’ variable regions, whereas most T cell studies sequence a small fraction of that region. Here, we adapted a B cell pipeline for undocumented alleles, genotype, and haplotype inference for full and partial AIRR-seq TCR data sets. The pipeline also deals with gene assignment ambiguities, which is especially important in the analysis of data sets of partial sequences. From the full and partial AIRR-seq TCR data sets, we identified 39 undocumented polymorphisms in T cell receptor Beta V (TRBV) and 31 undocumented 5 ′ UTR sequences. A subset of these inferences was also observed using independent genomic approaches. We found that a single nucleotide polymorphism differentiating between the two documented T cell receptor Beta D2 (TRBD2) alleles is strongly associated with dramatic changes in the expressed repertoire. We reveal a rich picture of germline variability and …

Show more

Dec 2022 • Annual Review of Condensed Matter Physics 13, 385-405, 2022

Studying Quantum Materials with Scanning SQUID Microscopy

Eylon Persky, Ilya Sochnikov, Beena Kalisky

Electronic correlations give rise to fascinating macroscopic phenomena such as superconductivity, magnetism, and topological phases of matter. Although these phenomena manifest themselves macroscopically, fully understanding the underlying microscopic mechanisms often requires probing on multiple length scales. Spatial modulations on the mesoscopic scale are especially challenging to probe, owing to the limited range of suitable experimental techniques. Here, we review recent progress in scanning superconducting quantum interference device (SQUID) microscopy. We demonstrate how scanning SQUID combines unmatched magnetic field sensitivity and highly versatile designs, by surveying discoveries in unconventional superconductivity, exotic magnetism, topological states, and more. Finally, we discuss how SQUID microscopy can be further developed to answer the increasing demand for imaging …

Show more

Dec 2022 • Cell Reports Physical Science

A cost-effective water-in-salt electrolyte enables highly stable operation of a 2.15-V aqueous lithium-ion battery

Meital Turgeman, Vered Wineman-Fisher, Fyodor Malchik, Arka Saha, Gil Bergman, Bar Gavriel, Tirupathi Rao Penki, Amey Nimkar, Valeriia Baranauskaite, Hagit Aviv, Mikhael D Levi, Malachi Noked, Dan Thomas Major, Netanel Shpigel, Doron Aurbach

Extensive efforts are currently underway to develop safe and cost-effective electrolytes for large-scale energy storage. In this regard, water-based electrolytes may be an attractive option, but their narrow electrochemical stability window hinders their realization. Although highly concentrated fluorinated electrolytes have been shown to be highly effective in suppression of water splitting, enabling significant widening of the applied potential range, they utilize expensive salts (e.g., lithium bis(trifluoromethane sulfonyl) imide [LiTFSI] or lithium trifluoromethane sulfonate [LiOTf]); hence, they cannot be considered for practical applications. Here, we demonstrate a cost-effective aqueous electrolyte solution combining 14 M LiCl and 4 M CsCl that allows stable operation of a 2.15-V battery comprising a TiO2 anode and LiMn2O4 cathode. Addition of CsCl to the electrolyte plays a double role in system stabilization: the added …

Show more

Dec 2022 • European Heart Journal-Digital Health

A novel contact-free atrial fibrillation monitor: a pilot study

Ben Sadeh, Ilan Merdler, Sapir Sadon, Lior Lupu, Ariel Borohovitz, Eihab Ghantous, Philippe Taieb, Yoav Granot, Orit Goldstein, Jonathan Calderón Soriano, Ricardo Rubio-Oliver, Joaquin Ruiz-Rivas, Zeev Zalevsky, Javier Garcia-Monreal, Maxim Shatsky, Sagi Polani, Yaron Arbel

Atrial fibrillation (AF) is a major cause of morbidity and mortality. Current guidelines support performing electrocardiogram (ECG) screenings to spot AF in high-risk patients. The purpose of this study was to validate a new algorithm aimed to identify AF in patients measured with a recent FDA-cleared contact-free optical device.

Show more

Dec 2022 • Materials Today Sustainability

Methyl formate and dimethyl ether electro-oxidation on PtPdSn catalyst supported on carbon nanotube decorated with carbon dots

Vijay Bhooshan Kumar, Diwakar Kashyap, Hanan Teller, Medhanie Gebremedhin Gebru, Aharon Gedanken, Alex Schechter

In this work methyl formate (MF) and dimethyl ether (DME) electro-oxidation was studied on equimolar ratio Pt-Pd-Sn catalyst supported on Vulcan Carbon XC-72, carbon nanotubes (CNT), and CNT - nitrogen-doped carbon dots (NCDs) composite. The ternary catalyst was synthesized by the ethylene glycol assisted thermal reduction method and NCDs were synthesized by a hydrothermal method in the presence of CNT to form CNT-NCDs composite, in which the NCDs are incorporated onto the CNT surface. The activity of the catalyst in the oxidation of MF and DME was analyzed using cyclic voltammetry and chronoamperometry techniques. The ternary catalyst supported on CNT-NCDs composite (Pt1Pd1Sn1/CNT-NCDs) showed peak oxidation current of 75 mA mg-1 and 365 mA mg-1 for DME and MF, respectively, highest among the studied Pt1Pd1Sn1/XC-72 and Pt1Pd1Sn1/CNT. The onset potential of DME …

Show more

Dec 2022 • Journal of Colloid and Interface Science

Strong coupling between an inverse bowtie Nano-Antenna and a J-aggregate

Adam Weissman, Maxim Shukharev, Adi Salomon

We demonstrate strong coupling between a single or few J-aggregates and an inverse bowtie plasmonic structure, when the J-aggregate is located at a specific axial distance from the metallic surface. Three hybrid modes are clearly observed, witnessing a strong interaction, with a Rabi splitting of up to 290 meV, the precise value of which significantly depends on the orientation of the J-aggregate with respect to the symmetry axis of the plasmonic structure. We repeated our experiments with a set of triangular hole arrays, showing consistent formation of three or more hybrid modes, in good agreement with numerical simulations.

Show more

Dec 2022 • arXiv preprint arXiv:1812.11450

Spin‐Spacetime Censorship

Jonathan Nemirovsky, Eliahu Cohen, Ido Kaminer

Quantum entanglement and relativistic causality are key concepts in theoretical works seeking to unify quantum mechanics and gravity. In this article, we show that the interplay between relativity theory and quantum entanglement has intriguing consequences for the spacetime surrounding elementary particles with spin. Classical and quantum gravity theories predict that a spin-generated magnetic dipole field causes a (slight) bending to the spacetime around particles, breaking its spherical symmetry. Motivated by the apparent break of spherical symmetry, we propose a very general gedanken experiment that does not rely on any specific theory of classical or quantum gravity, and analyze this gedanken experiment in the context of quantum information. We show that any spin-related deviation from spherical symmetry would violate relativistic causality. To avoid the violation of causality, the measurable spacetime around the particle's rest frame must remain spherically symmetric, potentially as a back-action by the act of measurement. This way, our gedanken experiment proves that there must be a censorship mechanism preventing the possibility of spacetime-based spin detection, which sheds new light on the interface between quantum mechanics and gravity. We emphasize that our proposed gedanken experiment is independent of any theory and by allowing spacetime to be quantized its purpose is to be used for testing present and future candidate theories of quantum gravity.

Show more

Nov 2022 • Measurement

Opto-mechanical magnetometer based on laser speckle correlation

Vismay Trivedi, Swapnil Mahajan, Mugdha Joglekar, Nirav Joshi, Vani Chhaniwal, Satish Kumar Dubey, Zeev Zalevsky, Bahram Javidi, Arun Anand

Magnetic field sensing plays vital role in vast range of areas such as navigation, military, and biomedical sciences. In recent times, optical sensors have made great advances, resulting in the development of magnetic field sensors based on optical principles due to their non-susceptibility to electromagnetic interference. Here, a simple and inexpensive approach for sensing magnetic field, that converts the magnetic field into a mechanical translation (of the sensing element) and then change into optical signals is presented. These optical signals are speckle patterns generated using a laser beam reflected off an optically rough metal cantilever which is exposed to the magnetic field. Magnetic field is quantified by measuring the changes in the speckle pattern using the intensity correlation technique. The approach can measure the static and time varying magnetic fields. The proposed system has a resolution of 2.2 and can measure magnetic fields with less than a 2% error.

Show more

Nov 2022 • Energy Storage Materials

Double gas treatment: A successful approach for stabilizing the Li and Mn-rich NCM cathode materials’ electrochemical behavior

Sandipan Maiti, Hadar Sclar, Judith Grinblat, Michael Talianker, Maria Tkachev, Merav Tsubery, Xiaohan Wu, Malachi Noked, Boris Markovsky, Doron Aurbach

Herein, a systematic surface modification approach via double gas (SO2 and NH3) treatment at elevated temperatures is described, aimed to achieve a stable electrochemical performance of Li and Mn-rich NCM cathode materials of a typical composition 0.33Li2MnO3•0.67LiNi0.4Co0.2Mn0.4O2 (HE-NCM). Partial surface reduction of Mn4+ and the formation of a modified interface comprising Li-ions conductive nano-sized Li2SO4/Li2SO3 phases are established. Li-coin cells’ prolonged cycling performance demonstrated significantly improved capacity retention (∼2.2 times higher than untreated cathode materials) for the double-gas-treated cathodes after 400 cycles at a 1.0 C rate. Stable discharge potential and lower voltage hysteresis during cycling were also achieved through the double gas treatment. Comparative electrochemical studies in full-pouch cells [vs. Graphite anodes] also demonstrated …

Show more

Nov 2022 • Measurement

Diamond protection for reusable ZnO coated fiber-optic measurement head in optoelectrochemical investigation of bisphenol A

Małgorzata Szczerska, Monika Kosowska, Paulina Listewnik, Michał Rycewicz, Mikhael Bechelany, Yafit Fleger, Dror Fixler, Paweł Jakóbczyk

Due to the global problem with plastic contaminating the environment, with bisphenol A (BPA) being one of the highest demand, effective monitoring and purification of the pollutants are required. The electrochemical methods constitute a good solution but, due to polymerization of electrochemical oxidation bisphenol A products and their adsorption to the surfaces, measurement head elements are clogged by the formed film. In this research, we propose a nanocrystalline diamond sheet protection for securing elements in direct contact with bisphenol A during electrochemical processes. The solution was presented on the example of a zinc oxide (ZnO) coating deposited on a fiber-optic end-face by Atomic Layer Deposition. Series of optical and electrochemical measurements were performed in a dedicated hybrid setup. The results show that ZnO can be modified during the electrochemistry leading to the drastic …

Show more

Oct 2022 • Journal of Applied Polymer Science

Polydopamine decorated carbon dots nanocomposite as an effective adsorbent for phenolic compounds

Moorthy Maruthapandi, Arumugam Saravanan, John HT Luong, Aharon Gedanken

Carbon dots (CDs) with an average diameter of 2.3 ± 0.5 nm were prepared from red cabbage by a facile one‐step hydrothermal process. The CDs and polydopamine (PDA) were then subjected to ultrasonication to form a polymer composite namely, PDA‐doped CDs (PDA@CDs). The PDA@CDs with an average size of 5 μm was proven as effective adsorbents for p‐chlorophenol (p‐CP) and p‐cyanophenol (p‐CNP) as two probing models. The adsorption capacity of PDA@CDs was estimated to be 153 mg/g for p‐CP and 178 mg/g for p‐CNP, compared favorably with those of various adsorbents used in the literature, only 24–123 mg/g. The PDA@CDs significantly improved the adsorption rate of the two phenols at neutral pH and room temperature. The adsorption kinetics was governed by the pseudo second‐order and intraparticle diffusion models. The PDA@CDs were reused as an active adsorbent …

Show more

Oct 2022 • arXiv preprint arXiv:2110.12418

Gas of sub-recoiled laser cooled atoms described by infinite ergodic theory

Eli Barkai, Günter Radons, Takuma Akimoto

The velocity distribution of a classical gas of atoms in thermal equilibrium is the normal Maxwell distribution. It is well known that for sub-recoiled laser cooled atoms L\'evy statistics and deviations from usual ergodic behaviour come into play. Here we show how tools from infinite ergodic theory describe the cool gas. Specifically, we derive the scaling function and the infinite invariant density of a stochastic model for the momentum of laser cooled atoms using two approaches. The first is a direct analysis of the master equation and the second following the analysis of Bertin and Bardou using the lifetime dynamics. The two methods are shown to be identical, but yield different insights into the problem. In the main part of the paper we focus on the case where the laser trapping is strong, namely the rate of escape from the velocity trap is for and . We construct a machinery to investigate the time averages of physical observables and their relation to ensemble averages. The time averages are given in terms of functionals of the individual stochastic paths, and here we use a generalisation of L\'evy walks to investigate the ergodic properties of the system. Exploring the energy of the system, we show that when it exhibits a transition between phases where it is either an integrable or non integrable observable, with respect to the infinite invariant measure. This transition corresponds to very different properties of the mean energy, and to a discontinuous behaviour of the fluctuations. Since previous experimental work showed that both and are attainable we believe that both phases could be explored also experimentally.

Show more

Oct 2022 • Materials Research Bulletin

In-situ design, characterization and use of durable superhydrophobic thin coatings applied on polymeric films

Naftali Kanovsky, Sarit Cohen, Shlomo Margel

Superhydrophobic coatings on polymeric films are in high demand due to their various real-world applications in a number of different fields. However, reported coatings lack durability or have complicated processes rendering them impractical. Here, tetraethylorthosilicate is polymerized via a modified Stöber method in the presence of a corona treated PP film (in-situ) which results in a thin silica-structured layer, covalently bonded to the PP film. Fluorocarbon silanes are then further reacted with the silica layer. The high surface roughness of the silica structures and low surface energy of the fluorocarbon silanes produce superhydrophobic surfaces. PP films coated with flake-like silica structures resulted in higher surface roughness and superhydrophobicity than the particle-like coating. Additionally, the flake-like silica coating exhibited good self-cleaning properties and durability to sandpaper abrasion tests. This …

Show more

Oct 2022 • arXiv preprint arXiv:2010.12220

Light chaotic dynamics in the transformation from curved to flat surfaces

Chenni Xu, Itzhack Dana, Li-Gang Wang, Patrick Sebbah

Light propagation on a two-dimensional curved surface embedded in a three-dimensional space has attracted increasing attention as an analog model of four-dimensional curved spacetime in laboratory. Despite recent developments in modern cosmology on the dynamics and evolution of the universe, investigation of nonlinear dynamics of light in non-Euclidean geometry is still scarce and remains challenging. Here, we study classical and wave chaotic dynamics on a family of surfaces of revolution by considering its equivalent conformally transformed flat billiard, with nonuniform distribution of refractive index. This equivalence is established by showing how these two systems have the same equations and the same dynamics. By exploring the Poincar\'{e} surface of section, the Lyapunov exponent and the statistics of eigenmodes and eigenfrequency spectrum in the transformed inhomogeneous table billiard, we find that the degree of chaos is fully controlled by a single geometric parameter of the curved surface. A simple interpretation of our findings in transformed billiards, the "fictitious force", allows to extend our prediction to other class of curved surfaces. This powerful analogy between two a prior unrelated systems not only brings forward a novel approach to control the degree of chaos, but also provides potentialities for further studies and applications in various fields, such as billiards design, optical fibers, or laser microcavities.

Show more

Oct 2022 • Advanced Quantum Technologies 5 (2), 2100121, 2022

Geometric phases and the Sagnac effect: Foundational aspects and sensing applications

Ismael L Paiva, Rain Lenny, Eliahu Cohen

Geometric phase is a key player in many areas of quantum science and technology. In this review article, we outline several foundational aspects of quantum geometric phases and their relations to classical geometric phases. We then discuss how the Aharonov-Bohm and Sagnac effects fit into this context. Moreover, we present a concise overview of technological applications of the latter, with special emphasis on gravitational sensing, like in gyroscopes and gravitational wave detectors.

Show more

Sep 2022 • arXiv preprint arXiv:2109.10326

Structured transmittance illumination coherence holography

Aditya Chandra Mandal, Tushar Sarkar, Zeev Zalevsky, Rakesh Kumar Singh

The coherence holography offers an unconventional way to reconstruct the hologram where an incoherent light illumination is used for reconstruction purposes, and object encoded into the hologram is reconstructed as the distribution of the complex coherence function. Measurement of the coherence function usually requires an interferometric setup and array detectors. This paper presents an entirely new idea of reconstruction of the complex coherence function in the coherence holography without an interferometric setup. This is realized by structured pattern projections on the incoherent source structure and implementing measurement of the cross-covariance of the intensities by a single-pixel detector. This technique, named structured transmittance illumination coherence holography (STICH), helps to reconstruct the complex coherence from the intensity measurement in a single-pixel detector without an interferometric setup and also keeps advantages of the intensity correlations. A simple experimental setup is presented as a first step to realize the technique, and results based on the computer modeling of the experimental setup are presented to show validation of the idea.

Show more

Aug 2022 • Scientific reports 12 (1), 1-9, 2022

Remote photonic detection of human senses using secondary speckle patterns

Zeev Kalyuzhner, Sergey Agdarov, Itai Orr, Yafim Beiderman, Aviya Bennett, Zeev Zalevsky

Neural activity research has recently gained signi cant attention due to its association with sensory information and behavior control. However, current methods of brain activity sensing require expensive equipment and physical contact with the subject.We propose a novel photonic-based method for remote detection of human senses. Physiological processes associated with hemodynamic activity due to activation of the cerebral cortex affected by different senses have been detected by remote monitoring of nano‐vibrations generated due to the transient blood ow to speci c regions of the brain. We have found that combination of defocused, self‐interference random speckle patterns with a spatiotemporal analysis using Deep Neural Network (DNN) allows associating between the activated sense and the seemingly random speckle patterns.

Show more

Aug 2022 • Optica 9 (3), 273-279, 2022

Quasi-static optical parametric amplification

Marc Jankowski, Nayara Jornod, Carsten Langrock, Boris Desiatov, Alireza Marandi, Marko Lončar, Martin M Fejer

We use dispersion-engineered PPLN nanowaveguides to demonstrate opti-cal parametric amplification without either temporal walk-off or group velocity dispersion. These quasi-static devices achieve large gains (> 145 dB/cm) across> 900 nanometers using picojoules of pump pulse energy.

Show more


Powered by Articali