Fabrication and Evaluation of Mechanical Properties of CF/GNP Composites

AbstractCNT/CFRP (Carbon Nanotube/ Carbon Fiber Reinforced Plastic) composites and GNP/CFRP (Graphene Nano platelet/ Carbon Fiber Reinforced Plastic) have several excellent mechanical properties including, high strength, young's modulus, thermal conductivity, corrosion resistance, electronic shielding and so on. In this study, CNT/CFRP composites were manufactured by varying the CNT weight ratio as 2wt% and 3wt%, While GNP/CFRP composites were manufactured by varying the GNP weight ratio as 0.5wt% and 1wt%. The composites ware manufactured by mechanical method (3-roll-mill). Tensile, impact and wear tests were performed according to ASTM standards D638, D256 and D3181 respectively. It was observed that, increasing the CNT weight ratio improves the mechanical properties, e.g., tensile strength, impact and wear resistance

Effects of Distilled Cervi Pantotrichum Cornu and Rehmannia glutinosa Pharmacopuncture at GB21 (Jianjing) on Heart Rate Variability: A Randomized and Double-blind Clinical Trial

AbstractBackground/PurposeThe purpose of this study was to use heart rate variability (HRV) to investigate the effects of distilled Cervi Pantotrichum Cornu pharmacopuncture and Rehmannia glutinosa pharmacopuncture on the autonomic nervous system.Materials and methodsForty healthy male participants were divided into two groups: the participants of the C-group received distilled Cervi Pantotrichum Cornu pharmacopuncture and those of the R-group received Rehmannia glutinosa pharmacopuncture. The study design was a randomized, double-blind clinical trial. Each participant received one of the two solutions injected at GB21 (Jianjing). The changes in HRV were measured seven times using the QECG-3: LXC3203 system (LAXTHA Inc. Korea). Time-dependent changes in HRV for each group were analyzed using the paired t test (significance level: p < 0.05), and the difference in the HRV fluctuations between the two experimental groups was evaluated using the independent sample test (significance level: p < 0.05).Results and conclusionThe results showed that Cervi Pantotrichum Cornu pharmacopuncture and Rehmannia glutinosa pharmacopuncture tended to activate the autonomic nervous system within the normal range. Cervi Pantotrichum Cornu pharmacopuncture tended to activate the sympathetic nervous system, whereas Rehmannia glutinosa pharmacopuncture tended to activate both the sympathetic and parasympathetic nervous systems

Implicit Inverse Force Identification Method of Acoustic Liquid-structure Interaction Finite Element Model

The two-field vibroacoustic finite-element (FE) model requires a relatively large number of degrees of freedom compared to the monophysics model, and the conventional force identification method for structural vibration can be adjusted for multiphysics problems. In this study, an effective inverse force identification method for an FE vibroacoustic interaction model of an interior fluid-structure system was proposed. The method consists of: (1) implicit inverse force identification based on the Newmark-$\beta$ time integration algorithm for stability and efficiency, (2) second-order ordinary differential formulation by avoiding the state-space form causing large degrees of freedom, (3) projection-based multiphysics reduced-order modeling for further reduction of degrees of freedom, and (4) Tikhonov regularization to alleviate the measurement noise. The proposed method can accurately identify the unmeasured applied forces on the in situ application and concurrently reconstruct the response fields. The accuracy, stability, and computational efficiency of the proposed method were evaluated using numerical models and an experimental testbed. A comparative study with the augmented Kalman filter method was performed to evaluate its relative performance.Comment: 31 Pages, 20 Figures, 5 Table

Limits of Binaries That Can Be Characterized by Gravitational Microlensing

Due to the high efficiency of planet detections, current microlensing planet searches focus on high-magnification events. High-magnification events are sensitive to remote binary companions as well and thus a sample of wide-separation binaries are expected to be collected as a byproduct. In this paper, we show that characterizing binaries for a portion of this sample will be difficult due to the degeneracy of the binary-lensing parameters. This degeneracy arises because the perturbation induced by the binary companion is well approximated by the Chang-Refsdal lensing for binaries with separations greater than a certain limit. For binaries composed of equal mass lenses, we find that the lens binarity can be noticed up to the separations of $\sim 60$ times of the Einstein radius corresponding to the mass of each lens. Among these binaries, however, we find that the lensing parameters can be determined only for a portion of binaries with separations less than $\sim 20$ times of the Einstein radius.Comment: 5 pages, 3 figures, 1 tabl

Two-gap and paramagnetic pair-breaking effects on upper critical field of SmFeAsO0.85_{0.85} and SmFeAsO0.8_{0.8}F0.2_{0.2} single crystals

We investigated the temperature dependence of the upper critical field [$H_{c2}(T)$] of fluorine-free SmFeAsO$_{0.85}$ and fluorine-doped SmFeAsO$_{0.8}$F$_{0.2}$ single crystals by measuring the resistive transition in low static magnetic fields and in pulsed fields up to 60 T. Both crystals show that $H_{c2}(T)$'s along the c axis [$H_{c2}^c(T)$] and in an $ab$-planar direction [$H_{c2}^{ab}(T)$] exhibit a linear and a sublinear increase, respectively, with decreasing temperature below the superconducting transition. $H_{c2}(T)$'s in both directions deviate from the conventional one-gap Werthamer-Helfand-Hohenberg theoretical prediction at low temperatures. A two-gap nature and the paramagnetic pair-breaking effect are shown to be responsible for the temperature-dependent behavior of $H_{c2}^c$ and $H_{c2}^{ab}$, respectively.Comment: 21 pages, 8 figure

Microlensing Detections of Planets in Binary Stellar Systems

We demonstrate that microlensing can be used for detecting planets in binary stellar systems. This is possible because in the geometry of planetary binary systems where the planet orbits one of the binary component and the other binary star is located at a large distance, both planet and secondary companion produce perturbations at a common region around the planet-hosting binary star and thus the signatures of both planet and binary companion can be detected in the light curves of high-magnification lensing events. We find that identifying planets in binary systems is optimized when the secondary is located in a certain range which depends on the type of the planet. The proposed method can detect planets with masses down to one tenth of the Jupiter mass in binaries with separations <~ 100 AU. These ranges of planet mass and binary separation are not covered by other methods and thus microlensing would be able to make the planetary binary sample richer.Comment: 5 pages, two figures in JPG forma

Neuroprotective and anti-oxidant effects of caffeic acid isolated from Erigeron annuus leaf

<p>Abstract</p> <p>Background</p> <p>Since oxidative stress has been implicated in a neurodegenerative disease such as Alzheimer's disease (AD), natural antioxidants are promising candidates of chemopreventive agents. This study examines antioxidant and neuronal cell protective effects of various fractions of the methanolic extract of <it>Erigeron annuus </it>leaf and identifies active compounds of the extract.</p> <p>Methods</p> <p>Antioxidant activities of the fractions from <it>Erigeron annuus </it>leaf were examined with [2,2-azino-bis(3-ethylbenz thiazoline-6-sulfonic acid diammonium salt)] (ABTS) and ferric reducing antioxidant power (FRAP) assays. Neuroprotective effect of caffeic acid under oxidative stress induced by H₂O₂was investigated with [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) and lactate dehydrogenase (LDH) assays.</p> <p>Results</p> <p>This study demonstrated that butanol fraction had the highest antioxidant activity among all solvent fractions from methanolic extract <it>E. annuus </it>leaf. Butanol fraction had the highest total phenolic contents (396.49 mg of GAE/g). Caffeic acid, an isolated active compound from butanol fraction, showed dose-dependent <it>in vitro </it>antioxidant activity. Moreover, neuronal cell protection against oxidative stress induced cytotoxicity was also demonstrated.</p> <p>Conclusion</p> <p><it>Erigeron annuus </it>leaf extracts containing caffeic acid as an active compound have antioxidative and neuroprotective effects on neuronal cells.</p

Excess cost of non-remission among outpatients with major depressive disorder

Background: The purpose of this study was to assess the economic benefit of achieving remission among outpatients with major depressive disorder (MDD) who are currently employed in Korea. Methods: Cross-sectional observational study. A total of 337 outpatients with MDD with paid jobs were recruited from 14 psychiatric clinics in Korea and were then divided into three groups as follows: new visit group (n = 128), remitted group (n = 100) and non-remitted group (n = 109). The 17-item Hamilton Depression Rating Scale (HAM-D) was used to decide whether a patient should be assigned to the remitted or non-remitted group. Direct medical and non-medical costs were measured via interview with the subjects. The World Health Organization Health and Work Performance Questionnaire (HPQ) were applied in order to measure the lost productive time (LPT) and related productivity costs. Results: The three groups did not show a significant difference in direct medical cost. However, the difference between the remitted group and non-remitted group was statistically significant (25.49 ± 52.99 vs. 44.79 ± 126.55, χ2 = 12.99, p = 0.0015). The remitted group demonstrated a significant improvement in productivity (particularly presenteeism) when compared with the new visit group (Z = −3.29, p = 0.001). Although the non-remitted group received treatment at psychiatric clinics similar to the remitted group, it lost 33 more working hours per month, which is compatible to $332 per month. Conclusion: These results suggest the economic importance of achieving remission in treating depression