A method of storing vector data in compressed form using clustering

The development of the machine learning algorithms for information search in recent years made it possible to represent text and multimodal documents in the form of vectors. These vector representations (embeddings) preserve the semantic content of documents and allow the search to be performed as the calculation of distance between vectors. Compressing embeddings can reduce the amount of memory they occupy and improve computational efficiency. The article discusses existing methods for compressing vector representations without loss of accuracy and with loss of accuracy. A method is proposed to reduce error by clustering vector representations using lossy compression. The essence of the method is in performing the preliminary clustering of vector representations, saving the centers of each cluster, and saving the coordinate value of each vector representation relative to the center of its cluster. Then, the centers of each cluster are compressed without loss of accuracy, and the resulting shifted vector representations are compressed with loss of accuracy. To restore the original vector representations, the coordinates of the center of the corresponding cluster are added to the coordinates of the displaced representation. The proposed method was tested on the fashion-mnist-784- euclidean and NYT-256-angular datasets. A comparison has been made of compressed vector representations with loss of accuracy by reducing the bit depth with vector representations compressed using the proposed method. With a slight (around 10 %) increase in the size of the compressed data, the absolute value of the error from loss of accuracy decreased by four and two times, respectively, for the tested sets. The developed method can be applied in tasks where it is necessary to store and process vector representations of multimodal documents, for example, in the development of search engines

Interactions of single and multi-layer graphene oxides with water, methane, organic solvents and HCl studied by 1H NMR

Abstract Contemporary characterisation techniques for graphenes are often performed for samples in a dried state or vacuum, which can lead to significant structural changes and difficulty in assessing the actual physical or physicochemical characteristics of graphenes in a colloid state. The interfacial phenomena between water or mixtures (of water with benzene, methane, or HCl) bound to single-layer graphene oxide (SLGO) and multi-layer graphene oxide (MLGO) in different dispersion media (CDCl3, CCl4, CDCl3/DMSO, air) were studied using low-temperature (200–280K) 1H NMR spectroscopy. Use of the NMR cryoporometry method allows determination of the textural characteristics of SLGO and MLGO depending on their hydration degree. It was found that SLGO in diluted suspensions is more agglomerated after freezing-thawing. This effect could be assigned to cryogelation of carbon sheets leading to a decrease in the specific surface area (from 1841 to 533m2/g) representing the area of sheets that are accessible for water that is unfrozen at subzero temperatures. The results obtained show that the cryoporometry method is appropriate for the investigation of the texture of both wetted and suspended graphene oxides

NANOSILICA A-300 INFLUENCE ON WATER STRUCTURES FORMED ON THE BIOACTIVE AGENT ENOXIL

The interactions of water and aqueous solutions of HCl with the Enoxil preparation and its composite system (1/1) Enoxil/SiO2 have been studied by low-temperature NMR spectroscopy. The antacid properties in the preparation, manifested in the transformation of concentrated solution of HCl in a weakly concentrated one, have been established. In the composite system adsorbed hydrochloric acid in a hydrophobic environment of CDCl3 may generate a system of clusters with different acid concentration, while the equilibrium is shifted toward less concentrated forms.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Textural Characteristics of Resorcinol—Formaldehyde Resin and Temperature Behavior of Bound Water Affected by Co-Adsorbed Trifluoroacetic Acid or Pyridine in Weakly Polar Organic Media

Resorcinol–formaldehyde resin (RFR) was synthesized as a porous material characterized by specific surface area of 140 m 2 /g and pore volume of 0.59 cm 3 /g with major proportions of broad mesopores and macropores. The interfacial behavior of water at low (h = 0.05 g of water/gram of dry RFR) and high (h = 2 g/g) hydration degrees depends on temperature and pore size filled by unfrozen water because its freezing-point depression increases in narrower pores. When water is mixed with co-adsorbates, the effects of such co-adsorbates as non-polar, weakly polar and polar organics depend on the amounts and the pore sizes. Even at a low hydration degree (h = 0.05 g/g), a portion of water can be displaced from pores by organic co-adsorbates because water has a relatively weak interaction with the RFR surface

High‐Sensitivity Photoelectrochemical Ultraviolet Photodetector with Stable pH‐Universal Adaptability Based on Whole Single‐Crystal Integrated Self‐Supporting 4 H ‐SiC Nanoarrays

Emerging photoelectrochemical (PEC) photodetectors (PDs) have notable advantages over conventional PDs and have attracted extensive attention. However, harsh liquid environments, such as those with high corrosivity and attenuation, substantially restrict their widespread application. Moreover, most PEC PDs are constructed by assembling numerous nanostructures on current collector substrates, which inevitably contain abundant interfaces and defects, thus greatly weakening the properties of PDs. To address these challenges, a high-performance pH-universal PEC ultraviolet (UV) PD based on a whole single-crystal integrated self-supporting 4H-SiC nanopore array photoelectrode is constructed, which is fabricated using a two-step anodic oxidation approach. The PD exhibits excellent photodetection behavior, with high responsivity (218.77 mA W−1), detectivity (6.64 × 1013 Jones), external quantum efficiency (72.47%), and rapid rise/decay times (17/48 ms) under 375 nm light illumination with a low intensity of 0.15 mW cm−2 and a bias voltage of 0.6 V, which is fall in the state-of-the-art of the wide-bandgap semiconductor-based PDs reported thus far. Furthermore, the SiC PEC PD exhibits excellent photoresponse and long-term operational stability in pH-universal liquid environments. The improved photodetection performance of the SiC PEC PD is primarily attributed to the synergistic effect of the nanopore array structure, integrated self-supporting configuration, and single-crystal structure of the whole photoelectrode