Exploration on efficient similar sentences extraction

Measuring the semantic similarity between sentences is an essential issue for many applications, such as text summarization, Web page retrieval, question-answer model, image extraction, and so forth. A few studies have explored on this issue by several techniques, e.g., knowledge-based strategies, corpus-based strategies, hybrid strategies, etc. Most of these studies focus on how to improve the effectiveness of the problem. In this paper, we address the efficiency issue, i.e., for a given sentence collection, how to efficiently discover the top-k semantic similar sentences to a query. The previous methods cannot handle the big data efficiently, i.e., applying such strategies directly is time consuming because every candidate sentence needs to be tested. In this paper, we propose efficient strategies to tackle such problem based on a general framework. The basic idea is that for each similarity, we build a corresponding index in the preprocessing. Traversing these indices in the querying process can avoid to test many candidates, so as to improve the efficiency. Moreover, an optimal aggregation algorithm is introduced to assemble these similarities. Our framework is general enough that many similarity metrics can be incorporated, as will be discussed in the paper. We conduct extensive experimental evaluation on three real datasets to evaluate the efficiency of our proposal. In addition, we illustrate the trade-off between the effectiveness and efficiency. The experimental results demonstrate that the performance of our proposal outperforms the state-of-the-art techniques on efficiency while keeping the same high precision as them.     

A Moment Method of the Log-Normal Size Distribution with the Critical Size Limit in the Free-Molecular Regime

The present work proposes new formulations of the moment in the free-molecular size regime involving (1) boundary equations at the critical size for evaporation, condensation, and nucleation, and (2) b coefficient functions for coagulation that are improved by two parameters (standard deviation and nondimensional critical size). Using these formulations based on the error function, the critical particle size is readily introduced into the log-normal moment method for applications in general aerosol dynamics. In the situation that the particle size distribution is located near the critical size, the proposed moment method (which considers the critical size limit) improves predictions of total particle number and particle volume concentrations as compared with previously well-used log-normal moment methods for sizes ranging from 0 to ∞. However, as the size distribution approaches to the continuum size regime, the influence of the critical size becomes smaller. Thus, the new formulations are expected to improve microphysical parameterization in the free-molecular regime in aerosol-transport models.

Copyright 2014 American Association for Aerosol Research     

Crystallinity of Acid Treated Corn Starch

The hydrolysis of corn starch by 1N H₂SO₄-30% ethanol aqueous solution at 45°C increased linearly with increasing of hydrolysis time for 20 d. The relative crystallinity of native corn starch showed 0.350 by X-ray diffraction and it increased gradually with increasing of hydrolysis time up to 8 d. The increasing ratio of 1/hydrolysis residue to hydrolysis time increased more largely than that of relative crystallinity after 14 d. On the other hand, the relative crystallinity of native corn starch by deuteration showed 0.341 very near to the value by X-ray diffraction. Moreover, this increasing ratio of the crystallinity accompanied by acid hydrolysis showed an inclination similar to that given by X-ray diffraction. These facts suggest that the exchanging of OH for OD groups may be caused very a little in crystalline region of corn starch granules.     

Oxidative Degradation of β-Cyclodextrin Induced by Lipid Peroxidation

The oxidative degradation of β-cyclodextrin (β-CD) induced by autoxidation of linoleate has been investigated in the solid system composed of β-CD and linoleate. β-CD was oxidized with a propagative oxidation of linoleate to induce the cleavage of its glucosidic linkage and this degradation proceeded proportionally with the moisture content in the solid system. The oxidative cleavage of β-CD gave several kinds of oligosaccharides which were composed of D -erythrose, D -arabinose, D -erythropentosulose, D -xylopentdial-dose, D -glucose and deoxyunsaturated hexose as their reducing terminals. These degradation of β-CD seemed to be initiated by certain radical species formed from the peroxidation of linoleate.     

GPC Profile Change of Potato Starch with Extrusion Processing

Native potato starch (moisture content 15%) was treated by twin screw extruder under four operating conditions with varying barrel temperatures (110°C–230°C). These modified starch samples were compared to native and drum-dried starch. Starch sample solution for gel chromatography was prepared by the three methods (acidic, alkaline, and neutral methods). They were subjected to gel chromatography on Toyopearl HW-75, and some difference was found among the three gel chromatographic patterns obtained from the same starch solution. This discrepancy among GPC patterns suggests formation of some types of anhydro-bonds between chains of amylopectin and or amylose in the extrusion process. Elevating barrel temperature increases degree of depolymerization. The size of fragments formed with the treatment is bigger than that of oligosaccharides but smaller than that of amylose.     

Flexible and Conductive 3D Printable Polyvinylidene Fluoride and Poly(N,N‐dimethylacrylamide) Based Gel Polymer Electrolytes

In this work, 3D printable gel polymer electrolytes (GPEs) based on N,N‐dimethylacrylamide (DMAAm) and polyvinylidene fluoride (PVDF) in lithium chloride containing ethylene glycol solution are synthesized and their physicochemical properties are investigated. 3D printing is carried out with a customized stereolithography type 3D gel printer named “Soft and Wet Intelligent Matter‐Easy Realizer” and free forming GPE samples having variable shapes and sizes are obtained. Printed PVDF/PDMAAm‐based GPEs exhibit tunable mechanical properties and favorable thermal stability. Electrochemical proprieties of the printed GPEs are carried out via impedance spectroscopy in the temperature range of 25–90 °C by varying PVDF content. Ionic conductivity as high as 6.5 × 10^?4 S cm^?1 is achieved at room temperature for GPE containing low PVDF content (5 wt%) and conductivity of the GPEs is increased as temperature rises.     

Grafting of poly(ethylene-block-ethylene oxide) onto a vapor grown carbon fiber surface by γ-ray radiation grafting

To modify the surface of vapor grown carbon fiber (VGCF), poly(ethylene-block-ethylene oxide) (PE-b-PEO, M_n=1400, PEO content=50 wt%) was successfully grafted onto the surface by using γ-ray irradiation of the PE-b-PEO-adsorbed VGCF in solvent-free system. It is found that the percentage of polymer grafting reached 15.0% when the PE-b-PEO-adsorbed VGCF was irradiated by γ-ray over 40 kGy dose at 110 °C, but at the lower irradiation temperature of 75 °C, the grafting reaction scarcely proceeded. This indicates that polymer radicals formed by γ-ray irradiation were successfully trapped by VGCF surface above melting point of PE-b-PEO. On the other hand, when the dispersion of VGCF in THF solution of PE-b-PEO was irradiated, the percentage of PE-b-PEO grafting was less than 4.0%. It was confirmed by a field-emission scanning electron microscope (FE-SEM) that the surface of the VGCF was uniformly covered by grafted PE-b-PEO. In addition, the surface free energy of ungrafted and PE-b-PEO-grafted VGCF was determined.     

An Additional Insight into the Correlation between the Distribution Ratios and the Aqueous Acidity of the TODGA System

Abstract

Extraction of Eu(III) and Am(III) from HNO₃ into the organic solvents using N,N,N′,N′‐tetraoctyl‐diglycolamide (TODGA) was investigated in order to study the detailed extraction reaction. The chemical species: 1:2 for metal:TODGA complex is present in polar diluents. On the other hand, the metal complexes need three or more TODGA molecules to remain stable in non‐polar diluents. The HNO₃ concentration dependence on the distribution ratio suggests that HNO₃ participates in the metal extraction. Infrared spectra indicate that the carbonyl oxygen coordinates with Eu(III), and luminescence lifetimes suggest that there are no water molecules in the inner coordination sphere of the extracted Eu‐complex.