• Title/Summary/Keyword: LPE method

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Fabrication and Its Characteristics of HgCdTe Infrared Detector (HgCdTe를 이용한 Infrared Detector의 제조와 특성)

  • 김재묵;서상희;이희철;한석룡
    • Journal of the Korea Institute of Military Science and Technology
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    • v.1 no.1
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    • pp.227-237
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    • 1998
  • HgCdTe Is the most versatile material for the developing infrared devices. Not like III-V compound semiconductors or silicon-based photo-detecting materials, HgCdTe has unique characteristics such as adjustable bandgap, very high electron mobility, and large difference between electron and hole mobilities. Many research groups have been interested in this material since early 70's, but mainly due to its thermodynamic difficulties for preparing materials, no single growth technique is appreciated as a standard growth technique in this research field. Solid state recrystallization(SSR), travelling heater method(THM), and Bridgman growth are major techniques used to grow bulk HgCdTe material. Materials with high quality and purity can be grown using these bulk growth techniques, however, due to the large separation between solidus and liquidus line on the phase diagram, it is very difficult to grow large materials with minimun defects. Various epitaxial growth techniques were adopted to get large area HgCdTe and among them liquid phase epitaxy(LPE), metal organic chemical vapor deposition(MOCVD), and molecular beam epitaxy(MBE) are most frequently used techniques. There are also various types of photo-detectors utilizing HgCdTe materials, and photovoltaic and photoconductive devices are most interested types of detectors up to these days. For the larger may detectors, photovoltaic devices have some advantages over power-requiring photoconductive devices. In this paper we reported the main results on the HgCdTe growing and characterization including LPE and MOCVD, device fabrication and its characteristics such as single element and linear array($8{\times}1$ PC, $128{\times}1$ PV and 4120{\times}1$ PC). Also we included the results of the dewar manufacturing, assembling, and optical and environmental test of the detectors.

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Branching Path Query Processing for XML Documents using the Prefix Match Join (프리픽스 매취 조인을 이용한 XML 문서에 대한 분기 경로 질의 처리)

  • Park Young-Ho;Han Wook-Shin;Whang Kyu-Young
    • Journal of KIISE:Databases
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    • v.32 no.4
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    • pp.452-472
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    • 2005
  • We propose XIR-Branching, a novel method for processing partial match queries on heterogeneous XML documents using information retrieval(IR) techniques and novel instance join techniques. A partial match query is defined as the one having the descendent-or-self axis '//' in its path expression. In its general form, a partial match query has branch predicates forming branching paths. The objective of XIR-Branching is to efficiently support this type of queries for large-scale documents of heterogeneous schemas. XIR-Branching has its basis on the conventional schema-level methods using relational tables(e.g., XRel, XParent, XIR-Linear[21]) and significantly improves their efficiency and scalability using two techniques: an inverted index technique and a novel prefix match join. The former supports linear path expressions as the method used in XIR-Linear[21]. The latter supports branching path expressions, and allows for finding the result nodes more efficiently than containment joins used in the conventional methods. XIR-Linear shows the efficiency for linear path expressions, but does not handle branching path expressions. However, we have to handle branching path expressions for querying more in detail and general. The paper presents a novel method for handling branching path expressions. XIR-Branching reduces a candidate set for a query as a schema-level method and then, efficiently finds a final result set by using a novel prefix match join as an instance-level method. We compare the efficiency and scalability of XIR-Branching with those of XRel and XParent using XML documents crawled from the Internet. The results show that XIR-Branching is more efficient than both XRel and XParent by several orders of magnitude for linear path expressions, and by several factors for branching path expressions.

Intracellular Lipid Accumulation Inhibition, Anticancer Activity, and Single Oral Dose Toxicity of Ethanolic Wolfiporia cocos Extracts (에탄올 복령추출물의 지방축적 억제활성, 항암활성 및 단회 경구 독성시험)

  • Park, Na-Hye;Lee, Hwa-Yong;Choi, Jong-Woon;Park, Seung-Chun
    • The Korean Journal of Mycology
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    • v.46 no.3
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    • pp.295-306
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    • 2018
  • In the present study, we compared the effects of 50% ethanolic extracts of Chinese and Korean Wolfiporia cocos (CPE and KPE) on in vitro lipid accumulation in 3T3-L1 cells and their anticancer activities in Sarcoma 180 cells. We further compared the anticancer activities and the 50% inhibitory concentrations ($IC_{50}$) of CPE with KPE with cultivated for one and two years in a landfill and a facility (LPE and FPE), respectively. In addition, the single oral dose toxicities of CPE and KPE were evaluated in mice. Lipid accumulation was inhibited after 48 hours, in CPE and KPE treated 3T3-L1 cells; however, no significant difference was observed between CPE and KPE in their lipid accumulation inhibitory activities. The anticancer activity of KPE was higher than that of CPE at $300{\mu}g/mL$ (p<0.05), revealing the possibility of an auxiliary biological means for origin identification. The anticancer activities of LPE and FPE were significantly stronger than that of CPE (p<0.05) but there was no difference between extracts from one- and two-year-old W. cocos, irrespective of the cultivation method. In single oral dose toxicity tests, CPE and KPE did not induce mortality during the 14-day observation. Thus, the 50% of lethal dose ($LD_{50}$) of CPE and KPE were estimated to be higher than 2,000 mg/kg. Taken together, our results indicate that the anticancer assay could be an auxiliary means of identifying the origin of W. cocos. In addition, artificial cultivation could be an alternative way to reduce the import of W. cocos. Lastly, 50% ethanolic W. cocos extracts could be potential candidates for obesity and cancer managements.

A Chemotaxonomic Study on Geographical Variations of Korean Fucales Plants 3. Total lipid analysis by 3-dimensional TLC (한국산 모자반목 식물의 지리적 변이체에 대한 생화학적 분류 3. 삼차원적 TLC에 의한 총지질의 분석)

  • 유순애
    • Journal of Plant Biology
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    • v.31 no.2
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    • pp.83-89
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    • 1988
  • The Fucales plants have very homogenous taxonomic characteristics at order level, but show many morphological variatations at species or subspecies levels. This study is one of the serial works to obtain more taxonomic data than morphotaxonomic ones and to clarify the taxonomic ranks and characteristics of Korean Fucales plants through physiological and biochemical analyses. Total lipid compositions of Korean Fucales plants were analyzed by the 3-dimensional TLC method. Major components of phospholipids (PA, PC, PG, PE, DPG, LPE, LPC), neutral fat TG and sterols were commonly contained in each species. Unknown lipids X1, X2 and X3 were contained in genus Sargassum, but Hizikia was lacking X3 and Myagropsis was lacking both X2 and X3. The latter contained unique X8. From the view-point of the phylogeny of lipid metabolism, Sargassum might be more closely related to Hizikia than to Myagropsis. A variant of S. patens from Seongsan showed minute metabolic difference from that of the typical plant; but a variant of S. serratifolium did not show any significant difference from that of the typical plant.

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Performance Analysis and improvement of Extension-interpolation (EI)/2D-DCT for Coding irregular Shaped object (불규칙 모양 물제의 부호화를 위한 확장-보간/2D-DCT의 성능 분석 및 개성 방안)

  • 조순제;강현수;윤병주;김성대;구본호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.3B
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    • pp.541-548
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    • 2000
  • In the MPEG-4 standardization phase, many methods for coding the irregular shaped VOP (video object Plane) have been researched. Texture coding is one of interesting research items in the MPEG-4. There are the Low pass extrapolation (LPE) padding, the shape adaptive DCT (SA-DCT), and the Extension-Interpolation (EI)/2D-DCT proposed in [1] as texture coding methods. the EI/2D-DCT is the method extending and interpolating luminance values from and Arbitrarily Shaped (AS) image segment into an 8 x 8 block and transforming the extended and interpolated luminance values by the 8x8 DCT. although the EI/2D-DCT and the SA-DCT work well in coding the As image segments. they are degraded since they use one-dimensional (1-D) methods such as the 1D-EI and the 1D-DCT in the two-dimensional (2-D) space. in this paper, we analyze the performance of the EI/2D-DCTand propose a new non-symmetric sig-sag scanning method, which non-symmetrically scans the quantized coefficients in the DCT domain to improve the EI/2D-DCT.

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Estimation on the Depth of Anesthesia using Linear and Nonlinear Analysis of HRV (HRV 신호의 선형 및 비선형 분석을 이용한 마취심도 평가)

  • Ye, Soo-Young;Baik, Seong-Wan;Kim, Hye-Jin;Kim, Tae-Kyun;Jeon, Gye-Rok
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.1
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    • pp.76-85
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    • 2010
  • In general, anesthetic depth is evaluated by experience of anesthesiologist based on the changes of blood pressure and pulse rate. So it is difficult to guarantee the accuracy in evaluation of anesthetic depth. The efforts to develop the objective index for evaluation of anesthetic depth were continued but there was few progression in this area. Heart rate variability provides much information of autonomic activity of cardiovascular system and almost all anesthetics depress the autonomic activity. Novel monitoring system which can simply and exactly analyze the autonomic activity of cardiovascular system will provide important information for evaluation of anesthetic depth. We investigated the anesthetic depth as following 7 stages. These are pre-anesthesia, induction, skin incision, before extubation, after extubation, Post-anesthesia. In this study, temporal, frequency and chaos analysis method were used to analyze the HRV time series from electrocardiogram signal. There were NN10-NN50, mean, SDNN and RMS parameter in the temporal method. In the frequency method, there are LF and HF and LF/HF ratio, 1/f noise, alphal and alpha2 of DFA analysis parameter. In the chaos analysis, there are CD, entropy and LPE. Chaos analysis method was valuable to estimate the anesthetic depth compared with temporal and frequency method. Because human body was involved the choastic character.

A Study of the Mutual Substitution State in $\textrm{Bi}_{2-xL}\textrm{Sr}_{2}\textrm{Ca}_{1+xL}\textrm{Cu}_{2}\textrm{O}_{8+d}$ Films Prepared by Liquid Phase Epitaxial Method (액상성장법으로 작성한 $\textrm{Bi}_{2-xL}\textrm{Sr}_{2}\textrm{Ca}_{1+xL}\textrm{Cu}_{2}\textrm{O}_{8+d}$ 막에서 각 원소들의 상호치환상태에 관한 연구)

  • Sin, Jae-Su;Ozaki, Hajime
    • Korean Journal of Materials Research
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    • v.9 no.8
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    • pp.849-853
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    • 1999
  • In the study, superconducting properties of $Bi_2$-x(sub)$LSr_2$Ca(sub)1+x(sub)$LCu_2$O(sub)8+d (x(sub)L=0, 0.05, 0.1, 0.2) films prepared by the LPE method was investigated. The peak decompositions of Sr3d and Ca2p XPS spectra, together with the EPMA results, elucidated the occupancies of Bi, Sr and Ca atoms on the SrO- and Ca-layers. The lattice parameter c monotonically increased with increasing x(sub)L for $0\leq$x(sub)L$\leq$0.2. The superconducting critical temperature T(sub)c showed a maximum value around x(sub)L=0.1. The x(sub)L dependence of the superconducting critical temperature T(sub)c and the lattice parameter c are explained by the changes of the excess oxygens in the BiO-layer. Since distribution and deficiency of the atoms in SrO-layer have influenced on superconducting properties and crystal structure.

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A Study on the Fabrication Process and Magnetic Properties of Buble Magnetic Materials. (버블자성재료의 제조 및 자기 특성에 관한 연구)

  • Park, Yong-Du;Kim, Jong-O
    • Korean Journal of Materials Research
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    • v.5 no.8
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    • pp.1040-1044
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    • 1995
  • Magnetic garnet films of (YSmLuCa)$_3$(FeGe)$\_$5/O$\_$12/ have been grown by the liquid phase eqitaxy method on the substrate of non-magnetic garnet Gd$_3$Ga$\_$5/O$\_$12/. The variation of Sm ion concentration were varied 0.3, 0.4, 0.6, mole/formula unit respectively. The magnetic properties of the samples for the bubble magnetic materials, such as, line width ΔH of ferromagnetic resonance (FMR), magnetic saturation induction 4$\pi$Ms, wall mobility u$\_$w/ uniaxial magnetic anisotropy energy Ku, were measured and discussed the relations between these properties. The line width ΔH decreases with increasing 4$\pi$Ms, and with decreasing Sm concentration. The anisotropy energy Ku increases not only with increasing Sm ion concentration, but also increasing 4$\pi$Ms. The value of wall mobility u$\_$w/ increase with increasing 4$\pi$Ms and decreases with increasing Sm concentration. We define a physical constant Eι from the fact that the product of 4$\pi$Ms and ΔH is constant with dimension of energy density. The Eι is dependent only on Sm concentration.density. The Eι is dependent only on Sm concentration.

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Lipidomic profiling of Skipjack tuna (Katsuwonus pelamis) by ultrahigh-performance liquid chromatography coupled to high resolution mass spectrometry

  • Hu, Lingping;Hu, Zhiheng;Chin, Yaoxian;Yu, Haixia;Xu, Jianhong;Zhou, Jianwei;Liu, Donghong;Kang, Mengli;Hu, Yaqin
    • Fisheries and Aquatic Sciences
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    • v.25 no.3
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    • pp.140-150
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    • 2022
  • A method of ultrahigh performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS) was established for characterization of the lipid profile of Skipjack tuna. Over 300 lipid molecular species were identified through cross-acquisition in both positive and negative ion mode. Phospholipids (PLs) were dominant in Skipjack tuna. Lysophosphatidylethanolamine (LPE), phosphatidylethanolamine (PE), lysophosphatidylcholine (LPC) and phosphatidylcholine (PC) were the main lipid molecular species in PLs, accounting for 89.24% of the total PLs. The ratio of sphingolipids (SLs) and glycerolipids (GLs) were considerable, accounting for 12.30% and 13.60% of the total lipids respectively. Ceramide (Cer) was the main lipid molecular species of SLs, accounting for 64.96% of total SLs, followed by sphingomyelin (SM), accounting for 25.45% of total SLs. Ether diglycerides (ether DG) were the main lipid molecular species of GLs (97.83%). The main fatty acids (FAs) are unsaturated fatty acids (UFAs) in Skipjack tuna. Besides, a new FAs class branched fatty acid esters of hydroxy fatty acids (FAHFA) was detected, together with the FA. The active lipids identified in this study can be used to evaluate the nutritional value of Skipjack tuna.