66 research outputs found

    Influence of humic acids on ZnO nanoparticles

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    The effect of natural organic matter, as humic acids, on the colloidal and thereby, biological, properties of nanoparticles is of great importance. Therefore, in this work we examined aggregative properties of ZnO nanoparticles with average size of 40 nm in differently concentrated solution of humic acids. Using the spectrophotometry method, it has been shown that the sedimentation rate of ZnO nanoparticles decreases in three times compared to distilled water. It has been found that with an increase in humic acids content from 10-10 to 10-4 mgL-1, the sedimentation rate of the particles increases

    Graphdiyne as a high-capacity lithium ion battery anode material

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    Using the first-principles calculations, we explored the feasibility of using graphdiyne, a 2D layer of sp and sp2 hybrid carbon networks, as lithium ion battery anodes. We found that the composite of the Li-intercalated multilayer ??-graphdiyne was C6Li7.31 and that the calculated voltage was suitable for the anode. The practical specific/volumetric capacities can reach up to 2719 mAh g-1/2032 mAh cm-3, much greater than the values of ???372 mAh g-1/???818 mAh cm -3, ???1117 mAh g-1/???1589 mAh cm-3, and ???744 mAh g-1 for graphite, graphynes, and ??-graphdiyne, respectively. Our calculations suggest that multilayer ??-graphdiyne can serve as a promising high-capacity lithium ion battery anode.open3

    Factors Affecting the Designation of Cerebrovascular Diseases as Work-Related in Administrative Litigation

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    The purpose of this study was to identify factors that could be used as standardized criteria for evaluating occupational diseases in initial assessments or requests for examination. Using 100 administrative litigation cases on the work-relatedness of cerebrovascular diseases (CVDs) by the Seoul Branch of the Korea Labor Welfare Corporation (KLWC) from 1997 to 2002, we estimated the relationship between the investigated variables and designation of the work-relatedness of the CVD. As for the age, the odds ratio of the acceptance rate of a case as work-related in subjects over 60 yr of age was 0.08 (95% CI, 0.01-0.75), which was compared to subjects under 30 yr of age. Regarding working hours, the odds ratio of the acceptance rate of a case as work-related in CVDs in those over 56 hr was 9.50 (95% CI, 1.92-47.10) when compared to those less than 56 hr. As for the benefit type, the odds ratio of the acceptance rate of a case as work-related in medical benefits was 5.74 (95% CI, 1.29-25.54), compared to survivor benefits. As for the criteria for defining situations as work overload, the odds ratio of the acceptance rate of a case as work-related in injured workers was 12.06 (95% CI, 3.12-46.62), compared to that in non-injured workers. Our findings show that the criteria for defining situations of work overload played an important role in assessing the work-relatedness of CVDs in administrative litigation, and it is necessary to make the scientific evidence on judgement of work-relatedness on overwork

    A Case of Placenta Increta Presenting as Delayed Postabortal Intraperitoneal Bleeding in the First Trimester

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    Placenta increta is an uncommon and life-threatening complication of pregnancy characterized by complete or partial absence of the decidua basalis. Placenta increta usually presents with vaginal bleeding during difficult placental removal in the third-trimester. Although placenta increta may complicate first and early second-trimester pregnancy loss, the diagnosis can be very difficult during early pregnancy and thus the lesion is difficult to identify. We encountered with a woman who was diagnosed with placenta increta after receiving emergency hysterectomy due to intraperitoneal bleeding 2 months after an uncomplicated dilatation and curettage in the first trimester. Therefore, we report this case with a brief review of the literature

    Polyolefin-based electrospun fibrous matrices embedded with magnetic nanoparticles for effective removal of viscous oils

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    © 2022 Elsevier LtdIn this work, we present a poly (ethylene-co-1-octene)-based fibrous matrix prepared via electrospinning for highly efficient removal of viscous oils. The sorbent consisting of linear low density polyethylene (LLDPE) allows selective absorption of crude oil spills at the water surface without the need for additional isolation of the matrix prior to the refining process. Moreover, the high specific pore volume of the LLDPE sorbent with uniform fibrous morphology was shown to enable the sorbent reach 81.5 ± 5.9% of its equilibrium absorption capacity within 5 min. Furthermore, magnetic nanoparticles (MNP) are incorporated into each fiber comprising the matrix to facilitate the recovery process via external magnetic field without altering the intrinsic absorption capacity. We envision that these sorbents offer a sustainable route for the quick and thorough clean-up of spilled oil due to their high absorption capacity, fast absorption rate, ease of recovery, and absence of secondary waste.11Nsciescopu

    Design of chiral guest-host liquid crystals for a transmittance-tunable smart window

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    © 2022 Optica Publishing GroupDichroic absorption dye-doped liquid crystal switching is preferred for transmittance control with maintaining visual clarity. In this paper, we present a parametric analysis of chiral guest-host liquid crystal (C-GHLC) switching for an enhanced transmittance-tunable smart window. Further analysis of the chiral twist power resulted in the proposal of a new modified transmittance governing formula for C-GHLC. The optimal C-GHLC cell design was determined through a comprehensive examination of the electro-optic transmittance change between transparent and opaque states by optimizing the chiral twist power in terms of ‘d/p’. Along with the theoretical parametric design of the C-GHLC cell, an optimal condition for the C-GHLC cell which can use commercial display driving environments was experimentally demonstrated for the first time. Consequently, an improved transmittance control (∆T ≈ 40.5%) with a low voltage (Von ≈ 18 V) and with a sufficiently fast response time (τ ≈ 12 ms) suitable for 60 Hz (< 16.7 ms) was confirmed.11Ysciescopu

    Improved Optical Transmittance Control of Dye-Doped Liquid Crystals Using PolarizationIndependent Molecular Rotation

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    A Two-Stage Affine Projection Algorithm with Mean-Square-Error-Matching Step-sizes

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    This paper proposes a two-stage affine projection algorithm (APA) with different projection orders and step-sizes. The proposed algorithm has a high projection order and a fixed step-size to achieve fast convergence rate at the first stage and a low projection order and a variable step-size to achieve small steady-state estimation errors at the second stage. The stage transition moment from the first to the second stage is determined by examining, from a stochastic point of view, whether the current error reaches the steady-state value. Moreover, in order to prevent the sudden drop of convergence rate on switching from a high projection order to a low projection order, a matching step-size method has been introduced to determine the initial step-size of the second stage by matching the mean-square errors (MSEs) before and after the transition moment. In order to continuously reduce steady-state estimation errors, the proposed algorithm adjusts the step-size of the second stage by employing a simple algorithm. Because of the reduced projection orders and variable step-size in the steady-state, the algorithm achieves improved performance as well as extremely low computational complexity as compared to the existing APAs with selective input vectors and APAs with variable step-size. (C) 2011 Elsevier B.V. All rights reserved.X111010sciescopu
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