• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 1993년도 정기학술강연회 발표논문 초록집
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• pp.124-124
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• 1993

Recently silt curtains have been increasingly used at a dredging or reclaiming site in a sea for the purpose of preventing the neighbouring waters from becoming turbid. However, the hydrodynamic forces acting on such a flexible structure have not been investigated well and the design criteria have not been established. The floating silt cur-tain treated in this study consists of floats, tension cables and curtain canvases. (omitted)

• 한국표면공학회지
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• 제26권3호
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• pp.143-148
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• 1993

Composition and microstructures of Silver-Tin alloy deposits from a pyrophosphate bath were studied under the D.C. electrolysis conditions. Cathode current efficiency and throwing power of alloy deposits de-creased with increasing current density. Tin content of Ag-Sn alloy deposits decreased noticeably with the cur-rent density and with decreasing pH. The preferred orientation of the deposits tended to change in sequence of (110)longrightarrow(111)longrightarrow(100) texture with increasing the cathode overpotential. The surface structure of alloy deposits showed the smooth surface structure with fine crystallites.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8271-8279
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• 2016

Background: Hepato-carcinogenesis is multifaceted in its molecular aspects. Among the interplaying agents are altered gap junctions, the proteasome/autophagy system, and mitochondria. The present experimental study was designed to outline the roles of these players and to investigate the tumor suppressive effects of curcumin with or without mesenchymal stem cells (MSCs) in hepatocellular carcinoma (HCC). Materials and Methods: Adult female albino rats were divided into normal controls and animals with HCC induced by diethyl-nitrosamine (DENA) and $CCl_4$. Additional groups treated after HCC induction were: Cur/HCC which received curcumin; MSCs/HCC which received MSCs; and Cur+MSCs/HCC which received both curcumin and MSCs. For all groups there were histopathological examination and assessment of gene expression of connexin43 (Cx43), ubiquitin ligase-E3 (UCP-3), the autophagy marker LC3 and coenzyme-Q10 (Mito.Q10) mRNA by real time, reverse transcription-polymerase chain reaction, along with measurement of LC3II/LC3I ratio for estimation of autophagosome formation in the rat liver tissue. In addition, the serum levels of ALT, AST and alpha fetoprotein (AFP), together with the proinflammatory cytokines $TNF{\alpha}$ and IL-6, were determined in all groups. Results: Histopathological examination of liver tissue from animals which received DENA-$CCl_4$ only revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules. Administration of curcumin, MSCs; each alone or combined into rats after induction of HCC improved the histopathological picture. This was accompanied by significant reduction in ${\alpha}$-fetoprotein together with proinflammatory cytokines and significant decrease of various liver enzymes, in addition to upregulation of Cx43, UCP-3, LC3 and Mito.Q10 mRNA. Conclusions: Improvement of Cx43 expression, nonapoptotic cell death and mitochondrial function can repress tumor growth in HCC. Administration of curcumin and/or MSCs have tumor suppressive effects as they can target these mechanisms. However, further research is still needed to verify their effectiveness.

• 대한환경공학회지
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• 제35권3호
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• pp.206-212
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• 2013

입상활성탄 흡착공정에서의 PFCs 11종의 파과 순서는 PFODA가 가장 빨리 파과에 도달하였고, 다음으로 PFHDA, PFTeDA, PFTDA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFOS, PFHpA 순으로 나타났으며, PFCs의 사슬(chain) 길이가 길어질수록 빨리 파과에 도달하였다. 최대 흡착량(X/M)의 경우는 PFODA가 2.43 ${\mu}g/g$으로 가장 낮게 나타났으며, PFHpA가 64.50 ${\mu}g/g$으로 가장 높은 최대 흡착량을 나타내었고, PFOA와 PFOS의 경우는 각각 55.37 ${\mu}g/g$ 및 60.72 ${\mu}g/g$으로 나타났다. 또한, 활성탄 사용률(CUR)의 경우는 PFODA가 0.291 g/day로 나타나 PFHpA의 0.026 g/day 보다 11.2배 정도 높은 활성탄 사용률을 나타내었다. 석탄계 GAC 신탄을 이용한 입상활성탄 흡착공정에서 11종의 PFCs에 대해 최대 흡착량(X/M)과 분자량(사슬 길이)과의 상관성을 평가해 본 결과, $r^2$가 0.89로 나타나 양호한 상관성을 나타내었다.

• Clinical and Experimental Reproductive Medicine
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• 제51권1호
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• pp.28-41
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• 2024

Objective: Chronic scrotal hyperthermia (SHT) can lead to serious disorders of the male reproductive system, with oxidative stress playing a key role in the onset of these dysfunctions. Thus, we evaluated the impact of caffeine, a potent antioxidant, on cellular and tissue disorders in mice with chronic SHT. Methods: In this experimental study, 56 adult male NMRI mice were allocated into seven equal groups. Apart from the non-treated control group, all were exposed to heat stress. Two groups, termed "preventive" and "curative," were orally administered caffeine. The preventive mice began receiving caffeine immediately prior to heat exposure, while for the curative group, a caffeine regimen was initiated 15 consecutive days following cessation of heat exposure. Each treated group was subdivided based on pairing with a positive control (Pre/ curative [Cur]+PC) or a vehicle (Pre/Cur+vehicle). Upon conclusion of the study, we assessed sperm characteristics, testosterone levels, stereological parameters, apoptosis, antioxidant and oxidant levels, and molecular markers. Results: Sperm parameters, testosterone levels, stereological parameters, biochemical factors (excluding malondialdehyde [MDA]), and c-kit gene expression were significantly elevated in the preventive and curative groups, especially the former, relative to the other groups. Conversely, expression levels of the heat shock protein 72 (HSP72) and nuclear factor kappa beta (NF-κβ) genes, MDA levels, and apoptotic cell density were markedly lower in both caffeine-treated groups relative to the other groups, with more pronounced differences observed in the preventive group. Conclusion: Overall, caffeine attenuated cellular and molecular abnormalities induced by heat stress in the testis, particularly in the mice treated under the preventive condition.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.138-145
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• 1996

A multilayer piezoelectric transformer (MPT) which generates a high voltage dc power with low driving voltage and high voltage setup ratio was made by the tape casting method. The measured electrical characteristics of the MPT agreed with the results simulated from the equivalent circuit of the MPT. With increasing the number of layer in the MPT, the resonance curve of the input cur-rent revealed an asymmetry due to the increasing input capacitance, while that of output dc voltages revealed symmetry. The MPT which has very thin layer was excellently characterized as low driving voltage and high voltage setup ratio. The output dc voltage is nonlinearly influenced by the number of layer in the MPT.

• E2M - 전기 전자와 첨단 소재
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• 제7권6호
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• pp.462-472
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• 1994

In this paper, electron drift velocity is experimentally measured in SF$_{6}$+N$_{2}$ Gas by induced cur-rent method and quantitaive production of electron transport coefficient is calculated by backward-prolongation of Boltzmann equation. Then electron energy distribution function and attachment coefficients are calculated. This paper can use the electron drift velocity by experimentally and the electron transport coefficient by calculated as a basic data of mixed Gas by comparing and investigating.g.

• Journal of Electrical Engineering and Technology
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• 제4권2호
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• pp.194-200
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• 2009

In this paper, the cooperative control scheme of micro sources and an ESS (Energy Storage System) during islanded operation is presented and evaluated by a simulation study. The ESS handles the frequency and voltage as a primary control. Then, the secondary regulation control returns the cur-rent power output of ESS into a pre-planned value. The simulation's results show that the proposed co-operative control scheme can regulate the frequency and voltage and reduce the consumption of the stored energy of ESS.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.296-298
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• 2009

Ac-dc 싸이리스터 컨버터에서 전류기준값의 부호가 변화할 경우에 적분항 초기값을 통해 전류제어 과도특성을 개선하는 연구가 있었다. 이 논문에서는 전류기준값의 기울기에 변화가 있을 때 그 변화를 일으키기 위한 전압을 계산하고 그 값을 점호각 $\alpha$로 환산하여 시스템에 적용시켜 변곡점 부근에서의 전류제어 특성을 개선하는 방법을 제시하였다. 또한 전류기준값에 노이즈가 포함된 경우 LPF 유/무에 따른 특성변화와 노이즈가 포함되지 않은 경우 LPF 유/무에 따른 특성변화를 관찰하였다.

• E2M - 전기 전자와 첨단 소재
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• 제8권4호
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• pp.451-457
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• 1995

Most important study on development of high-Tc superconducting magnet is magnetic properties with design conditions To study optimal design condition of high-Tc superconducting magnet, small size solenoid magnet was designed and simulated. Design conditions are radius of bobbin, radius of magnet, length of magnet, critical cur-rent and notch size. We know that intensity of magnetic fields was controled by critical current and uniformity of magnetic fields was controled by notch size. The optimal design conditions to get the high intensity and uniformity of magnetic field in this experiments were radius of bobbin=3[cm], radius of magnetic=12[cm], length of Z=10[cm], notch size=6[cm] and critical current=12[A].