• Title/Summary/Keyword: HWE

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Growth of high quality ZnTe epilayers used for an far-infrared sensor and radiation detector

  • Kim, B. J.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.6
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    • pp.105-110
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    • 2002
  • ZnTe epilayers have been successfully grown on (100) CaAs substrate by hot wall epitaxy (HWE) with Zn reservoir. Optimum growth condition has been determined by a four-crystal rocking curve (FCRC). It was found that Zn partial pressure from h reservoir has a strong influence on the quality of grown films. Under the determined optimum growth condition, ZnTe epitaxial films with thickness of 0.72~24.8${\mu}m$ were grown for studying the effect of the thickness on crystalline quality. The FCRC results indicated that the quality of ZnTe films becomes higher rapidly with increase of thickness up to 6${\mu}{\textrm}{m}$. The best value of the FWHM of the few crystal rocking curve, 66 arcsec, was obtained on the film with $12{\mu}m$ in thickness. Until now, this result shows the best quality of ZnTe/GaAs films in reported.

Growth of High Quality $Cd_{0.96} Zn_{0.04} Te$ Epilayers Used for an Far-infrared Sensor and Radiation Detector

  • Kim, B. J.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.6
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    • pp.111-117
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    • 2002
  • The high quality and a nearly stoichometric growth of $Cd_{1-y} Zn_y$/Te(y=0.04) epilayers have been successfully grown on GaAs substrate by hot wall epitaxy (HWE) by optimizing the growth condition including the preheating treatment and Cd reservoir temperature. The relationship between quality and thickness was examined and best value of FWHM from X-ray rocking curve of 121 arcsec are obtained. Also, emission peaks related to the recombination of free excitons such as the ground state and the first excited state were observed in the PL spectrum at 4.2K. The ($A^0$, X) emission related to Cd vacancy and deep level emission was not measured. These results indicated that the grown CZT/GaAs epilayer was high qualify and purity.

A Study on Patterning Techniques by sliced unit with square woods's color bars (각목 색상 배치에 의한 문양막대의 횡절단 무늬편을 이용한 문양구성 연구)

  • Kim, Ji-Geon
    • Journal of the Korea Furniture Society
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    • v.20 no.5
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    • pp.431-439
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    • 2009
  • When we look at the pattern techniques of wooden furniture in the 19th century Joeson Dynasty, we see that furniture patterns in the main living room were showy and colorful while furniture patterns in the library room, where noble men used to study, were natural and moderate, retaining the actual color of the material without any artificial coloring. Even the serial patterns in the Hwe-Jang technique, Which were used rarely, used moderate techniques. such as weaving in patterns with colorless woods - willow and black persimmon ets. - rather than using excessive techniques. However, considering the marquetry&intarsia technique of ceramic and the silver string intarsia technique of metal then current, wood work must also have been technically advanced. Korean modern wood furniture needs remedies to improve the standard of sound wood work techniques. This study shows that pattern unit production, composition techniques, and color effects etc. Using colored patterns bars, by improving the pattern composition techniques of Marquetry&Intarsia, can be substituted for the production logic of modern manufactured furniture.

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Effect of Extraction Conditions on Yield and Quality of Extracts in Astragalas manbranaceus Bunge, Angelica gigas Nakai (황기, 당귀 추출물의 추출조건이 추출물의 수율 및 품질에 미치는 영향)

  • 이미숙;이근보;한명규;박상순
    • The Korean Journal of Food And Nutrition
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    • v.14 no.6
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    • pp.543-547
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    • 2001
  • The hot water extraction(HWE) has many problems such as a low extract yield and a reduced flagrance by excessive heating during concentration process notwithstanding it has been the general method to get the extract from the traditional chinese medicines Astragalas manbranaceus Bunge and Angelica gigas Nakai. For that reason, adopted the alcohol extraction In this research and got the good results of the 65% and 75% extract yield of Astragalas manbranaceus Bunge and Angelica gigas Nakai respectively, 15% and 36% increased compare with 50% and 39% (w/w) of HWE. The differences of extraction process between the HWE and alcohol extraction is substituting alcohol for water of extraction were concentrated at the relatively low temperature 90$\^{C}$ compare with the thermal extraction temperature 104$\^{C}$ . This alcohol extract, has the outstanding effect collecting the original fragrance at the low temperature. Applying this extract to starch syrup and beverage, expected that those contain a sufficient flavor as well as fragrance without artificial spices.

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Lack of Association Between LIG4 Gene Polymorphisms and the Risk of Breast Cancer: A HuGE Review and Meta-analysis

  • Zhou, Li-Ping;Luan, Hong;Dong, Xi-Hua;Jin, Guo-Jiang;Man, Dong-Liang;Shang, Hong
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.7
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    • pp.3417-3422
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    • 2012
  • Objective: Non-homologous end joining (NHEJ) is one of the pathways of repair of DNA double-strand breaks. A number of genes involved in NHEJ have been implicated as breast cancer susceptibility genes such as LIG4. However, some studies have generated conflicting results. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigate association between LIG4 gene polymorphisms in the NHEJ pathway and breast cancer risk. Methods: Studies focusing on the relationship between LIG4 gene polymorphisms and susceptibility to breast cancer were selected from the Pubmed, Cochrane library, Embase, Web of Science, Springerlink, CNKI and CBM databases. Data were extracted by two independent reviewers and the meta-analysis was performed with Review Manager Version 5.1.6 and STATA Version 12.0 software, calculating odds ratios (ORs) with 95% confidence intervals (95%CIs). Results: According to the inclusion criteria, we final included seven studies with a total of 10,321 breast cancer cases and 10,160 healthy controls in the meta-analysis. The results showed no association between LIG4 gene polymorphisms (rs1805386 T>C, rs1805389 C>T, rs1805388 C>T and rs2232641 A>G) and breast cancer risk, suggesting that the mutant situation of these SNPs neither increased nor decreased the risk for breast cancer. In the subgroup analysis by Hardy-Weinberg equilibrium (HWE) and ethnicity, we also found no associations between the variants of LIG4 gene and breast cancer risk among HWE, non-HWE, Caucasians, Asians and Africans. Conclusion: This meta-analysis suggests that there is a lack of any association between LIG4 gene polymorphisms and the risk of breast cancer.

Growth of $Cd_{1-x}Zn_xS $ Thin films Using Hot Wall Epitaxy Method and Their Photoconductive Characteristics (HWE에 의한 $Cd_{1-x}Zn_xS $박막의 성장과 광전도 특성)

  • 홍광준;유상하
    • Korean Journal of Crystallography
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    • v.9 no.1
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    • pp.53-63
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    • 1998
  • The Cd1-xZnxS thin films were grown on the Si(100) wafers by a hot wall epitaxy method (HWE). the source and substrate temperature are 600℃ and 440℃, respectively. The crystalline structure of epilayers was investigated by double crystal X-ray diffraction (DCXD). Hall effect on the sample was measured by the van der Pauw method and the carrier density and mobility dependence of Hall characteristics on temperature was also studied. In order to explore the applicability as a photoconductive cell, we measured the sensitivity (γ), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that the best photoconductive characteristic were observed in the Cd0.53Zn0.47S samples annealed in Cu vapor comparing with in Cd, Se, air and vacuum vapour. Then we obtained the sensitivity of 0.99, the value of pc/dc of 1.65 × 107, the MAPD of 338mW, and the rise and decay time of 9.7 ms and 9.3 ms, respectively.

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Photocurrent properties for $CdGa_2Se_4$ single crystal thin film grown by using hot wall epitaxy(HWE) method (Hot Wall Epitaxy(HWE)법에 의한 $CdGa_2Se_4$ 단결정 박막의 광전류 연구)

  • You, Sang-Ha;Hong, Kwang-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.124-125
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    • 2007
  • Single crystal $CdGa_2Se_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the polycrystal source of $CdGa_2Se_4$ at $630^{\circ}C$ prepared from horizontal electric furnace. The photocurrent and the absorption spectra of $CdGa_2Se_4$/SI(Semi-Insulated) GaAs(100) are measured ranging from 293K to 10K. The temperature dependence of the energy band gap of the $CdGa_2Se_4$, obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T) = 2.6400 eV - $(7.721{\times}10^{-4}\;eV/K)T^2$/(T + 399 K). Using the photocurrent spectra and the Hopfield quasicubic model, the crystal field energy$({\Delta}cr)$ and the spin-orbit splitting energy$({\Delta}so)$ for the valence band of the $CdGa_2Se_4$ have been estimated to be 106.5 meV and 418.9 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-},\;B_{1^-},\;and\;C_{11^-}$ exciton peaks.

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Immunomodulating activity of Sargassum horneri extracts in RAW264.7 macrophages (RAW264.7 대식세포에서 괭생이 모자반 추출물의 면역활성 증진 효과)

  • Kim, Dong-Sub;Sung, Nak-Yun;Park, Sang-Yun;Kim, Geon;Eom, Ji;Yoo, Jin-Gon;Seo, In-Ra;Han, In-Jun;Cho, Young-Baik;Kim, Kyung-Ah
    • Journal of Nutrition and Health
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    • v.51 no.6
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    • pp.507-514
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    • 2018
  • Purpose: Sargassum horneri (S. horneri) is a species of brown macroalgae that is common along the coast of Japan and Korea. The present study investigated the immuno-modulatory effects of different types of S. horneri extracts in RAW264.7 macrophages. Methods: S. horneri was extracted by three different methods, hot water extraction, 50% ethanol extraction, and supercritical fluid extraction. Cell viability was then measured by MTT assay, while the production levels of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-6 (IL-6), and nitric oxide (NO) were measured by enzyme-linked immunosorbent assay and Griess assay, respectively. The expression and activation levels of inducible NO synthase (iNOS), mitogen-activated protein kinase (MAPK) and nuclear factor ${\kappa}B$ ($NF-{\kappa}B$) were examined by western blot analysis. Results: The three different S. horneri extracts were nontoxic against RAW 264.7 cells up to $50{\mu}g/mL$, among which treatment with hot water extract (HWE) of S. horneri significantly enhanced the production of TNF-${\alpha}$, IL-6, and NO in a dose-dependent manner. Hot water extract of S. horneri also increased the expression level of iNOS, suggesting that up-regulation of iNOS expression by HWE of S. horneri was responsible for the induction of NO production. In addition, treatment of RAW 264.7 macrophages with HWE of S. horneri increased the phosphorylation levels of ERK, p38 and JNK. Furthermore, the activation and subsequent nuclear translocation of $NF-{\kappa}B$ was enhanced upon treatment with HWE of S. horneri, indicating that HWE of S. horneri activates macrophages to secrete TNF-${\alpha}$, IL-6 and NO and induces iNOS expression via activation of the $NF-{\kappa}B$ and MAPKs signaling pathways. Conclusion: Taken together, these findings suggest that HWE of S. horneri possesses potential as a functional food with immunomodulatory activity.

Effects of Saenghyetang on Learning and Memory Performances in Mice (생혜탕(生慧湯)이 흰쥐의 학습(學習)과 기억(記憶)에 미치는 영향(影響))

  • Yu Geum-Ryoung;Chang Gyu-Tae;Kim Jang-Hyeon
    • The Journal of Pediatrics of Korean Medicine
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    • v.15 no.1
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    • pp.77-104
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    • 2001
  • The effects of the oriental herbal medicine Saenghyetang(SHT, 生慧湯), which consists of Rehmanniae Radix (熟地黃 九蒸: was made by 9th steam) 40g, Corni Fructus(山茱黃) 16g, Polygalae Radix(遠志) 8g, Zizyphi Spinosae Semen(酸棗仁) 2g, Biotae Semen(柏子仁 去油: oil ingredient was removed) 20g, Poria Cocos(茯笭) 12g, Ginseng Radix(人蔘) 12g, Acori Graminei Rhizoma(石菖蒲) 2g, Sinapis Semen(白芥子) 8g, on learning ability and memory were investigated. Hot water extract(HWE) and ethanol extract(EE) from SHT were used for the studies. Learning ability and memory are related to modifications of synaptic strength among neurons that interactive. Enhanced synaptic coincidence detection leads to improved learning ability and memory. If the NMDA receptor, a synaptic coincidence detector, acts as a graded switch for memory formations, enhanced signal detection by NMDA receptors should enhance learning ability and memory. It was shown that NR2B was increased in the forebrains of oriental medicine-administrated mice, leading to enhanced activation of NMDA receptors and facilitating synaptic potentiation in response to stimulation at 10-100 Hz. These HWE-SHT treated mice exhibited that superior ability in learning and memory when performing various behavioral tasks, showing that NR2B is enhanced by HWE-SHT treatment and also is critical in gating the age-dependent threshold for plasticity and memory formation. NMDA receptor-dependent modifications, which were mediated in part by HWE administration, of synaptic efficacy, therefore, represent a mechanism for associative learning ability and memory. Results suggest that oriental medical enhancement of NR2B contributes to increase intelligence and memory in mammals On the other hand, to examine the effects of EE-SHT on the learning ability and memory in experimental mice, EE-SHT was tested on passive and active avoidance responses. The EE-SHT ameliorated the memory retrieval deficit induced by ethanol in mice, but not other memory impairments. EE-SHT(10, 20mg/100 g, p.o.) did not affect the passive avoidance responses of normal mice in the step through and step down tests, the conditioned and unconditioned avoidance responses of normal mice in the shuttle box, lever press performance tests and the ambulatory activity of normal mice in a normal condition. However, EE-SHT at 20 mg/kg significantly decrease the spontaneous motor activity during the shuttle box test, and also to extend the sleeping time induced by pentobarbital in mice. These results suggest that SHT has an ameliorating effect on memory retrieval impairments and a weak tranquilizing action.

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Polyphenol Compound Contents and Physiological Activities in Various Extracts of the Vitex rotundifolia Stems (순비기나무(Vitex rotundifolia) 줄기 추출물의 폴리페놀 함량과 생리활성)

  • Joo, Eun-Young;Lee, Yang-Suk;Kim, Nam-Woo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.7
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    • pp.813-818
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    • 2007
  • For this study, extracts of Vitex rotundifolia stems were prepared using reflux water extraction (WE), reflux ethanol extraction (EE) and hot water extract under high pressure (HWE). The extracts were investigated for the total content of phenolic compounds, antioxidant activities, and inhibitory potencies for xanthine oxidase and tyrosinase. The EE extraction method yielded the highest content of polyphenol compounds (176.34 mg/g). The electron donating abilities (EDA) were 93.46${\sim}$96.92%, when extracts were assayed at 1.0 mg/mL. The superoxide dismutase (SOD)-like activity was the highest in the WE extract (47.32% at 1.0 mg/mL). The nitrite scavenging abilities (pH 1.2) were 84.61${\sim}$88.36% and the inhibition of xanthine oxidase were over 90% at 0.5 mg/mL. Tyrosinase inhibition of HWE and WE were 57.84% and 53.47% respectively. It implies that V. rotundifolia stems have potent physiological activities and their activities were differently exhibited depending on solvent fractions.