Effects of Li2CO3 addition on structural and magnetic properties of M-type strontium hexaferrite have been studied by using crystallographic and magnetic measurements. The samples were prepared thru ...the flux-aided solid state reaction by adding small fractions of Li2CO3 powder to the SrFe12O19 precursors. The key action of a flux salt is strongly dependent upon solubility and dispersion of the salt ions over the grain. So, the crystallographic, microstructural, and macroscopic magnetic characteristics have been explored in relations with the role of flux salt by means of XRD, FE-SEM, VSM, and Mössbauer spectroscopy. Finally, the result strongly suggests that most of the flux salt Li1+ ions distribute throughout the grain surface and act like a surfactant that enhance the degree of grain separation and thereby reduce the coercivity of the sample.
In the field of speaker verification (SV), the development of noise-robust systems is a challenge for their deployment in real-world environments. Noise variability compensation is a common strategy ...for increasing the robustness to noise variations. The performance of noise compensation depends on how well the noise variability, which is inherent in within-class variability, is estimated. However, to date, there is no information about the true noise variability that could reduce the gap between the empirical and true statistics. Most studies assume that true noise covariates are independent. This study aims to demonstrate that the assumption that true noise variability has a conditional independence structure rather than an independence structure. This assumption was motivated by our previous findings, which revealed that optimal within-class variability has a conditional independence structure in text-dependent speaker verification (TD-SV) in clean environments. This indicates that the optima of all the variabilities in within-class variability, except noise variability, has a conditional independence structure; however, it is unknown whether this is also true for optimal noise variability. Our assumption was supported by the experimental results obtained under noisy TD-SV trials using systems built with graphical least absolute shrinking and selection operator-based probabilistic linear discriminant analysis, which achieved up to 10% relative equal error rate improvements.
A human stress monitoring patch integrates three sensors of skin temperature, skin conductance, and pulsewave in the size of stamp (25 mm × 15 mm × 72 μm) in order to enhance wearing comfort with ...small skin contact area and high flexibility. The skin contact area is minimized through the invention of an integrated multi-layer structure and the associated microfabrication process; thus being reduced to 1/125 of that of the conventional single-layer multiple sensors. The patch flexibility is increased mainly by the development of flexible pulsewave sensor, made of a flexible piezoelectric membrane supported by a perforated polyimide membrane. In the human physiological range, the fabricated stress patch measures skin temperature with the sensitivity of 0.31 Ω/°C, skin conductance with the sensitivity of 0.28 μV/0.02 μS, and pulse wave with the response time of 70 msec. The skin-attachable stress patch, capable to detect multimodal bio-signals, shows potential for application to wearable emotion monitoring.
Effects of stoichiometric La3+–Li1+ co-substitution on magnetic properties of M-type strontium hexaferrites Sr1-xLaxFe12-x/2Lix/2O19 (x = 0, 0.25, 0.4, 0.5, 0.6) have been studied by using ...crystallographic and magnetic measurements. Samples were prepared thru conventional ceramic technique and their powder X-ray diffraction profiles were checked by the Rietveld method using GSAS package. Field emission scanning electron microscopy images show that lithium addition derives the enhanced degree of grain separation, which significantly affects the coercivity and anisotropy constant as examined by vibrating sample magnetometer measurement. 57Fe Mössbauer spectra of the samples show that Li1+ ions preferentially occupy the 2a sites, which causes the decrease of MS with lithium addition.
The present research proposes the present porous polydimethylsiloxane (PDMS) layer for the skin trouble reduced daily life skin attachable devices. The present research proposes the new pores forming ...method in the PDMS by crystallization and dissolution of the citric acid in the PDMS for fabricating high uniform and small size pores. The present porous PDMS layer (i) decreases the pore size 93.2%p and increases the pore size uniformity 425%p compared to the conventional porous PDMS layer of mixing sugars and PDMS; (ii) is able to be fabricated in the thickness of 21-101 µm by spin-coating; (iii) has the 2.2 times higher water vapor transmission rate (947 ± 10.8 g/day•m
) compared to the human skin water vapor transmission rate. The present porous PDMS layer reduces the skin trouble effectively by having the high water vapor permeability, therefore is applicable to the human daily-life skin attachable devices.
Effects of La3+ and Cu1+ co-doping on the structural and the magnetic properties of M-type strontium hexaferrite have been studied by using crystallographic and magnetic measurements. Stoichiometric ...samples have been prepared by a conventional ceramic technique with repeated sintering at 1300 °C for 24 hours in the air. XPS Cu 2p scan shows that dominant valence state of Cu is +1. Analyses of the hysteresis curve reveals that MS increases and HC decreases with La-Cu content x. Room temperature Mössbauer spectral analysis indicates that Cu1+ preferentially replaces Fe3+ at 4f2 site, which is consistent with the increase of MS with respect to the La3+-Cu1+ co-doping.
There has been a recent report regarding the existence of solid‐like H2 adsorption in nanoporous materials. Herein, we employed grand canonical Monte Carlo (GCMC) simulations on a series of ...metal–organic frameworks with 1D and 3D channels to investigate the limitation of a model‐based approach in estimating the H2 adsorption capacities. The excess hydrogen uptakes of several structures with pore sizes ranging from 5 to 37 Å were computationally predicted. The pore volume and the density of adsorbed H2 were obtained by fitting the Tóth equation to the excess H2 isotherm data from the simulation. The results were compared with the data obtained from direct simulation. Sensitivity analyses show that the pore volume and the density of adsorbed H2, predicted from model‐based fitting, are not accurate enough to estimate the adsorbed H2 density and the pore volume, especially for the materials with 1D channels.
In this work, we investigated the limitation of a model‐based approach that has been used to estimate the H2 storage capacity of nanoporous materials. We found that the pore volume and adsorbed H2 density obtained from the model‐based approach is not accurate enough to estimate the H2 adsorption capacities.
Enterococci are considered to be environmental mastitis-causing pathogens that can easily spread antimicrobial resistance or virulence genes via horizontal transfer. In this study, the molecular ...characteristics of enterococci from bulk tank milk were investigated to assess the importance of dairy herd management. A total of 338 enterococci (305
and 33
) were isolated from 1584 batches of bulk tank milk samples from 396 farms affiliated with four dairy companies in Korea, and significant differences (40.6-79.7%) (
< 0.05) in the prevalence of enterococci were observed in the samples from different companies. Enterococci showed the highest resistance to tetracycline (TET) (73.4%), followed by doxycycline (DOX) (49.7%) and erythromycin (ERY) (46.2%), while two enterococci isolates showed resistance to vancomycin (VAN). Among 146 tetracycline (TET) and ERY-resistant enterococci, each 50 (19.4%) enterococci carried combination-resistance and transposon gene types
(B) +
(M) +
and
(B) +
(L) +
(M) +
, respectively. The virulence genes such as
(99.0%),
(97.7%),
(95.7%), and
(85.9%) were highly conserved in
and significantly predominated over
(
< 0.001). Our results indicate that pathogens from bulk tank milk can also become a reservoir for the dissemination of antimicrobial resistance and virulence factors through cross-contamination processes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We propose a method, called bi-point input, for convolutional neural networks (CNNs) that handle variable-length input features (e.g., speech utterances). Feeding input features into a CNN in a ...mini-batch unit requires that all features in each mini-batch have the same shape. A set of variable-length features cannot be directly fed into a CNN because they commonly have different lengths. Feature segmentation is a dominant method for CNNs to handle variable-length features, where each feature is decomposed into fixed-length segments. A CNN receives one segment as an input at one time. However, a CNN can consider only the information of one segment at one time, not the entire feature. This drawback limits the amount of information available at one time and consequently results in suboptimal solutions. Our proposed method alleviates this problem by increasing the amount of information available at one time. With the proposed method, a CNN receives a pair of two segments obtained from a feature as an input at one time. Each of the two segments generally covers different time ranges and therefore has different information. We also propose various combination methods and provide a rough guidance to set a proper segment length without evaluation. We evaluate the proposed method on the spoofing detection tasks using the ASVspoof 2019 database under various conditions. The experimental results reveal that the proposed method reduces the relative equal error rate (EER) by approximately 17.2% and 43.8% on average for the logical access (LA) and physical access (PA) tasks, respectively.
We propose watch-type sweat rate sensors capable of automatic natural ventilation by integrating miniaturized thermo-pneumatic actuators, and experimentally verify their performances and ...applicability. Previous sensors using natural ventilation require manual ventilation process or high-power bulky thermo-pneumatic actuators to lift sweat rate detection chambers above skin for continuous measurement. The proposed watch-type sweat rate sensors reduce operation power by minimizing expansion fluid volume to 0.4 ml through heat circuit modeling. The proposed sensors reduce operation power to 12.8% and weight to 47.6% compared to previous portable sensors, operating for 4 hours at 6 V batteries. Human experiment for thermal comfort monitoring is performed by using the proposed sensors having sensitivity of 0.039 (pF/s)/(g/m
h) and linearity of 97.9% in human sweat rate range. Average sweat rate difference for each thermal status measured in three subjects shows (32.06 ± 27.19) g/m
h in thermal statuses including 'comfortable', 'slightly warm', 'warm', and 'hot'. The proposed sensors thereby can discriminate and compare four stages of thermal status. Sweat rate measurement error of the proposed sensors is less than 10% under air velocity of 1.5 m/s corresponding to human walking speed. The proposed sensors are applicable for wearable and portable use, having potentials for daily thermal comfort monitoring applications.
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