Supercurrent in a Double Quantum Dot Estrada Saldaña, J C; Vekris, A; Steffensen, G ...
Physical review letters,
2018-Dec-21, Letnik:
121, Številka:
25
Journal Article
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We demonstrate the Josephson effect in a serial double quantum dot defined in a nanowire with epitaxial superconducting leads. The supercurrent stability diagram adopts a honeycomb pattern. We ...observe sharp discontinuities in the magnitude of the critical current, I_{c}, as a function of dot occupation, related to doublet to singlet ground state transitions. Detuning of the energy levels offers a tuning knob for I_{c}, which attains a maximum at zero detuning. The consistency between experiment and theory indicates that our device is a faithful realization of the two-impurity Anderson model.
Consumer demands and requirements by regulatory agencies to use more environmentally friendly and less polluting packaging have directed researchers to consider packaging materials that are naturally ...derived or made from renewable resources to replace or reduce use of synthetic polymers. Biodegradable and/or edible films have the potential to reduce some traditional synthetic polymeric packaging materials for specific applications. In recent years, biodegradable films prepared with animal and vegetable proteins have received increasing attention and are increasingly being used in the food-packaging industry due to their relative abundance, film-formation capacity, biodegradability, and nutritional value. However, the ideal protein films for food-packaging application should be strong, be elastic, and have very low permeability. The aim of this review is to offer a comprehensive view of recent state-of-the-art protein-based films as biodegradable materials applicable to food packaging with special reference to the application and combination of technological advances. Such advances include plasticization, cross-linking techniques, nanotechnology, and composite films. The results indicate that the functional properties of protein films are still not comparable with those of synthetic films, but there are promising potential methodologies that might further improve the mechanical and barrier properties of protein-based films. Nanocomposite films with well-controlled structures comprise an up-and-coming area of research. Research into nanocomposite film includes the opportunity to design biofilms and packaging materials with the precisely desired functional properties. By employing natural agents with antimicrobial and antioxidant properties, these materials promise to provide maintenance during storage time and to increase the shelf life of food products.
Fermentation is an essential process step to develop precursor compounds for aroma and flavour characteristics of chocolate, as well as preventing germination of the cocoa bean. Despite the ...importance of the role of microorganisms during the chocolate production, to date, there are some discrepancies of the “cocobiota” community found during fermentation and the impact of starter culture in fermented cocoa beans. This review provides both a detailed overview of the starter cultures used in fermented cocoa beans and the microbial diversity involved during this process, and an in-depth discussion of the methods used to identify these microorganisms. In this review, we included only published articles from 2008 to 2018 in English language. A total of forty-seven studies contributed to the description of the cocobiota from 13 different countries. In detail, we observed that the most common fermentation method used is the wooden box, followed by heap. Interestingly, 37% of the studies cited in this review did not mention the type of cocoa variety studied. Most of the techniques used to identify the microbiota are fingerprinting based (DGGE); however, few studies have been using next-generation technologies to elucidate the possible functions and interactions among microbes. Our results showed a greater diversity of yeasts if compared with bacterial involved in the fermentation. This review will help researchers seeking to design starter cultures to drive cocoa bean fermentation, and thus achieve a homogenous mass of fermented cocoa beans as well as serve as a guide for assessing methodologies for the identification of microorganisms.
•The ecology of fermented cocoa is influenced by intrinsic and extrinsic factors.•Saccharomyces, Lactobacillus and Acetobacter are the main taxa in cocoa fermentation.•Several studies focus on the identification of “cocobiota”.•Needed to correct identification and characterisation of starter cultures•Cocoa fermentation must standardise according regions and variety cultivated.
We studied the two-step crystallisation process of a magnetic active 2D-granular system placed on different lens concaveness and under the action of an alternating magnetic field which controls its ...effective temperature. We have observed that the two-step features of the crystallisation process are more evident as the depth of the parabolic potential increases. At the initial formation of the nucleus, as a first step, in the central region of the lens an amorphous aggregate is formed. In an ulterior second step, this disordered aggregate, due to the effective temperature and the perturbations caused by the impacts of free particles moving in the surrounding region, evolves to an ordered crystalline structure. The nucleus size is larger for deeper concaveness of the parabolic potential. However, if the depth of the parabolic potential exceeds a certain value, the reordering process of the second step does not occur. The crystal growth occurs similarly; small disordered groups of particles join the nucleus, forming an amorphous shell of particles which experiments a rearranging while the aggregate grows. In the explored range of the depths of the parabolic potential, crystallisation generally occurs quicker as the deeper parabolic potential is. Also, aggregates are more clearly round-shaped as parabolic potential depth increases. On the contrary, the structures are more branched for a smaller depth of the parabolic potential. We studied the structural changes and features in the system by using the sixth orientational order parameter and the packing fraction.
We present a novel, fully three-dimensional approach to soft material characterization and constitutive modeling with relevance to soft biological tissue. Our approach leverages recent advances in ...experimental techniques and data-driven computation. The experimental component of this approach involves in situ mechanical loading in a magnetic field (using MRI), yielding the entire deformation tensor field throughout the specimen regardless of the possible irregularities in its three-dimensional shape. Characterization can therefore be accomplished with data at a reduced number of deformation states. We refer to this experimental technique as MR-u. Its combination with powerful approaches to inverse modeling, specifically methods of model inference, would open the door to insightful mechanical characterization for soft materials. In recent computational advances that answer this need, we have developed new, data-driven inverse techniques to infer the model that best explains the physics governing observed phenomena from a spectrum of admissible ones, while maintaining parsimony of representation. This approach is referred to as Variational System Identification (VSI). In this communication, we apply the MR–u approach to characterize soft polymers regarding them as surrogates of soft biological tissue, and using VSI, we infer the physically best-suited and parsimonious mathematical models of their mechanical response. We demonstrate the performance of our methods in the face of noisy data with physical constraints that challenge the identification of mathematical models, while attaining high accuracy in the predicted response of the inferred models.
We report direct-detection constraints on light dark matter particles interacting with electrons. The results are based on a method that exploits the extremely low levels of leakage current of the ...DAMIC detector at SNOLAB of 2–6×10−22 A cm−2. We evaluate the charge distribution of pixels that collect <10e− for contributions beyond the leakage current that may be attributed to dark matter interactions. Constraints are placed on so-far unexplored parameter space for dark matter masses between 0.6 and 100 MeV c−2. We also present new constraints on hidden-photon dark matter with masses in the range 1.2–30 eV c−2.
The functional features of spatial networks depend upon a non-trivial relationship between the topological and physical structure. Here, we explore that relationship for spatial networks with radial ...symmetry and disordered fractal morphology. Under a geometric graphs approach, we quantify the effectiveness of the exchange of information in the system from center to perimeter and over the entire network structure. We mainly consider two paradigmatic models of disordered fractal formation, the Ballistic Aggregation and Diffusion-Limited Aggregation models, and complementary, the Viscek and Hexaflake fractals, and Kagome and Hexagonal lattices. First, we show that complex tree morphologies provide important advantages over regular configurations, such as an invariant structural cost for different fractal dimensions. Furthermore, although these systems are known to be scale-free in space, they have bounded degree distributions for different values of an euclidean connectivity parameter and, therefore, do not represent ordinary scale-free networks. Finally, compared to regular structures, fractal trees are fragile and overall inefficient as expected, however, we show that this efficiency can become similar to that of a robust hexagonal lattice, at a similar cost, by just considering a very short euclidean connectivity beyond first neighbors.
This Letter presents an efficient, fast, and straightforward two-step demodulating method based on a Gram-Schmidt (GS) orthonormalization approach. The phase-shift value has not to be known and can ...take any value inside the range (0,2π), excluding the singular case, where it corresponds to π. The proposed method is based on determining an orthonormalized interferogram basis from the two supplied interferograms using the GS method. We have applied the proposed method to simulated and experimental interferograms, obtaining satisfactory results. A complete MATLAB software package is provided at http://goo.gl/IZKF3.
We have been reporting several new techniques of analysis and synthesis applied to Phase Shifting Interferometry (PSI). These works are based upon the Frequency Transfer Function (FTF) and how this ...new tool of analysis and synthesis in PSI may be applied to obtain very general results, among them; rotational invariant spectrum; complex PSI algorithms synthesis based on simpler first and second order quadrature filters; more accurate formulae for estimating the detuning error; output-power phase noise estimation. We have made our cases exposing these aspects of PSI separately. Now in the light of a better understanding provided by our past works we present and expand in a more coherent and holistic way the general theory of PSI algorithms. We are also providing herein new material not reported before. These new results are on; a well defined way to combine PSI algorithms and recursive linear PSI algorithms to obtain resonant quadrature filters.
Large collaborative research networks provide opportunities to jointly analyze multicenter electronic health record (EHR) data, which can improve the sample size, diversity of the study population, ...and generalizability of the results. However, there are challenges to analyzing multicenter EHR data including privacy protection, large-scale computation resource requirements, heterogeneity across sites, and correlated observations. In this paper, we propose a federated algorithm for generalized linear mixed models (Fed-GLMM), which can flexibly model multicenter longitudinal or correlated data while accounting for site-level heterogeneity. Fed-GLMM can be applied to both federated and centralized research networks to enable privacy-preserving data integration and improve computational efficiency. By communicating a limited amount of summary statistics, Fed-GLMM can achieve nearly identical results as the gold-standard method where the GLMM is directly fitted to the pooled dataset. We demonstrate the performance of Fed-GLMM in numerical experiments and an application to longitudinal EHR data from multiple healthcare facilities.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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