• Title/Summary/Keyword: Potential barrier

Search Result 645, Processing Time 0.027 seconds

Protective effects of red orange (Citrus sinensis [L.] Osbeck [Rutaceae]) extract against UVA-B radiation-induced photoaging in Skh:HR-2 mice

  • Yoon Hee Kim;Cho Young Lim;Jae In Jung ;Tae Young Kim;Eun Ji Kim
    • Nutrition Research and Practice
    • /
    • v.17 no.4
    • /
    • pp.641-659
    • /
    • 2023
  • BACKGROUND/OBJECTIVES: The skin is the outermost organ of the human body and plays a protective role against external environmental damages, such as sunlight and pollution, which affect anti-oxidant defenses and skin inflammation, resulting in erythema or skin reddening, immunosuppression, and epidermal DNA damage. MATERIALS/METHODS: The present study aimed to investigate the potential protective effects of red orange complex H extract (ROC) against ultraviolet (UV)-induced skin photoaging in Skh:HR-2 mice. ROC was orally administered at doses of 20, 40, and 80 mg/kg/day for 13 weeks, along with UV irradiation of the mice for 10 weeks. RESULTS: ROC improved UV-induced skin barrier parameters, including erythema, melanin production, transepidermal water loss, elasticity, and wrinkle formation. Notably, ROC inhibited the mRNA expression of pro-inflammatory cytokines (interleukin 6 and tumor necrosis factor α) and melanogenesis. In addition, ROC recovered the UV-induced decrease in the hyaluronic acid and collagen levels by enhancing genes expression. Furthermore, ROC significantly downregulated the protein and mRNA expression of matrix metalloproteinases responsible for collagen degradation. These protective effects of ROC against photoaging are associated with the suppression of UV-induced phosphorylation of c-Jun NH2-terminal kinase and activator protein 1 activation. CONCLUSIONS: Altogether, our findings suggest that the oral administration of ROC exerts potential protective activities against photoaging in UV-irradiated hairless mice.

Determination of the Depletion Depth of the Deep Depletion Charge-Coupled Devices

  • Kim Man-Ho
    • Journal of Electrical Engineering and Technology
    • /
    • v.1 no.2
    • /
    • pp.233-236
    • /
    • 2006
  • A 3-D numerical simulation of a buried-channel CCD (Charge Coupled Device) with a deep depletion has been performed to investigate its electrical and physical behaviors. Results are presented for a deep depletion CCD (EEV CCD12; JET-X CCD) fabricated on a high-resistivity $(1.5k\Omega-cm)\;65{\mu}m$ thick epi-layer, on a $550{\mu}m$ thick p+ substrate, which is optimized for X-ray detection. Accurate predictions of the Potential minimum and barrier height of a CCD Pixel as a function of mobile electrons are found to give good charge transfer. The depletion depth approximation as a function of gate and substrate bias voltage provided average errors of less than 6%, compared with the results estimated from X-ray detection efficiency measurements. The result obtained from the transient simulation of signal charge movement is also presented based on 3-Dimensional analysis.

A High Efficiency Ozone Generation Using a Electrode-edge Discharge and a Dielectric-Barrier Discharge (전극연면방전(電極沿面放電)과 유전체장벽방전(誘電體障壁放電)을 공용(共用)한 고효율(高效率) 오존발생(發生))

  • Choi, Jae-Gu;Moon, Jae-Duk
    • Proceedings of the KIEE Conference
    • /
    • 1995.07c
    • /
    • pp.1410-1412
    • /
    • 1995
  • A high efficiency ozone generation using both of a electrode-edge discharge and a dielectric-harrier discharge from a modified silent type ozone generator has been proposed and studied for small scale applications. It is found that the output ozone concentration of the proposed generator depended greatly upon the air gap spacing and the applied power frequency and voltage on the ozone generation. The ozone generator showed higher ozone concentration than the same size of the ceramic type surface ozone generator(Masuda type one). And, it is found that the generator had a potential to be used as an ozone generator for small scale applications.

  • PDF

Adsorption Mechanisms of NH3 on Chlorinated Si(100)-2×1 Surface

  • Lee, Hee-Soon;Choi, Cheol-Ho
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.3
    • /
    • pp.775-778
    • /
    • 2012
  • The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)-$2{\times}1$ surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a $S_N2$ type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-$NH_2$ bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile.

A Reinvestigation of the Fragmentation of 2-Carbena-1,3-dioxolane by CASSCF and CASPT2 Calculations

  • Park, Bong-Jin;Hrovat, David A.;Borden, Weston Thatcher
    • Bulletin of the Korean Chemical Society
    • /
    • v.25 no.2
    • /
    • pp.260-262
    • /
    • 2004
  • In agreement with the results of previous MP2 calculations by Sauers, B3LYP, CASSCF, and CASPT2 calculations on the parent 2-carbena-1,3-dioxolane show that it fragments to ethylene plus $CO_2$ by a concerted pathway with only a small energy barrier. Not only is fragmentation via stepwise C-O bond cleavage computed to be a much higher energy pathway, but the singlet diradical that would be an intermediate along such a reaction path is not even computed to be a local minimum on the potential energy surface.

The Effect of Sb2O3 Additive on the Electrical Properties of ZnO Varistor (Sb2O3 첨가제가 ZnO 배리스터의 전기적 특성에 미치는 영향)

  • Kim, Yong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.65 no.10
    • /
    • pp.1697-1701
    • /
    • 2016
  • The leakage conduction and critical voltage characteristic of ZnO ceramic were investigated as a function of $Sb_2O_3$ concentration. Leakage conduction in the ohmic region increased with increasing $Sb_2O_3$ concentration and was attributed to the potential barrier height. The nonlinear coefficient increased with an increasing amount of $Sb_2O_3$. It was found that increases in the apparent critical voltages were associated with the lowered donor concentration in the grain boundary of between two ZnO grains. And the decrease of donor concentration on doping with $Sb_2O_3$ additive was attributed to the lowered capacitance in the grain boundary layer.

Possibility & Limitation of 1D Nano Scale Electron Shielder (나노 구조물을 이용한 전자선 차폐 가능성과 한계 조사)

  • Ahn, Sung-Jun;Lee, Bum-Su;Kim, Chong-Yeal
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.5 no.2
    • /
    • pp.109-112
    • /
    • 2007
  • The possibility and limitation of one dimensional nano scale electron shielder is briefly discussed. A Nano scale electron shielder will reduce the weight and size of shielding materials. However, practical application still requires further research. In this work, we discuss general problems related to nano scale electron shielder, by taking an arbitrary one dimensional potential barrier as an example.

  • PDF

A study on the rules and policy of the maritime and aviation supply chain security (해상 및 항공물류보안의 법규 및 정책에 관한 연구)

  • Choi, Byoung-Kwon
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
    • /
    • v.42
    • /
    • pp.247-274
    • /
    • 2009
  • The supply chain security programs are designed to prevent terrorist attacks on world transit system, and to help protect the passengers and workers who use these systems on a daily basis. as evidenced by the train bombings in London and Madrid in recent years, the threats to America's transit systems are real. After 9 11 terrors in 2001, security problem is appearing to every nations and international organizations main pending issue than any problem and various countermeasure is prepared. Security is the major issue in international trade, with significant potential costs and economic impact. So, We need to ensure that supply chain security does not become a new non-tariffs barrier. The aim of this study is to examine the international maritime and aviation law on the supply chain security. Also I review the supply chain security in U.S. and other countries.

  • PDF

Targeting the Future : Asian Aerospace, Its Current Status and Challenges (미래로의 지향: 아시아의 항공산업, 그 현황과 도전)

  • 김준모
    • Journal of Korea Technology Innovation Society
    • /
    • v.1 no.3
    • /
    • pp.338-350
    • /
    • 1998
  • Asian countries, ranging from China and Japan to Korea and Taiwan, differ in their industrial development stages to support the aerospace industry, and market access conditions. Despite these differences, all these countries target the aerospace industry as one of their future industries. The phenomenon challenges the conventional view that entry into the aerospace sector follows a gradual path from simple hanger repairs to license production, and to international collaboration. This paper reviews current status of the Asian aerospace with a dichotomy of the conventional promotion and Fast-Track promotion strategies. Analysis revealed that multiple entry points, in terms of technological level, exist in the aerospace industry, while the conventional thinking still holds validity. Then the paper presents potential obstacles and challenges these Asian countries would face in the promotion of the industry.

  • PDF

Study on permeability improved multi-layer encapsulation on Ethylene Terephthalate(PET) (PET 기판위의 투습율 향상을 위한 다층 보호막에 관한 연구)

  • Han, Jin-Woo;Kang, Hee-Jin;Kim, Jong-Yeon;Kang, Dong-Hun;Han, Jung-Min;Oh, Yong-Cheul;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2006.11a
    • /
    • pp.313-314
    • /
    • 2006
  • In this paper, the inorganic-organic thin film encapsulation layer was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter and Spin-Coater system, the various kinds of inorganic and organic thin-films were deposited onto the Ethylene Terephthalate(PET) and their interface properties between organic and inorganic layer were investigated Results indicates that the SiON/PI/SiON/PI/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) application.

  • PDF