• Title, Summary, Keyword: NR

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An active noise control window system to reduce noise rating in low frequency band (저주파 대역의 소음 평가 지수 개선을 위한 창문형 능동 소음 제어기)

  • Oh, Wongeun
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.5
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    • pp.331-337
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    • 2018
  • In this paper, we apply the NR (Noise Rating) to the evaluation of the residual noise of the window type ANC (Active Noise Control) and study the active noise controller for minimizing the NR value in rooms. We proposed a shape of a noise shaping filter of the Filtered-E LMS (Least Mean Square) algorithm that reduces the NR value within the effective operating frequency band of the ANC. The usefulness of the proposed scheme is verified by simulation and showed that the NR value of the residual noise is lower than the filters used in the conventional psychoacoustic ANC.

Effect of Intracellular Calcium Chelator on Phosphorylation of Spinal N-Methyl-D-Aspartate Receptor following Electroacupuncture Stimulation in Rats (칼슘 저해제가 전침자극에 의한 척수 N-Methyl-D-Aspartate 수용체 인산화에 미치는 영향)

  • Jung, Taek-Guen;Cho, Sung-Woo;Kang, Yeon-Kyeong;Chang, Dong-Ho;Lee, In-Seon
    • Journal of Korean Medicine Rehabilitation
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    • v.20 no.1
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    • pp.27-36
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    • 2010
  • Objectives : We investigated the role of intracellular calcium chelator, bis-(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid(BAPTA), on the modulation of phosphorylation of the spinal N-methyl-D-aspartate receptor(NMDAR) NR1 and NR2B subunits following electroacupuncture(EA). Methods : Bilateral 2 Hz EA stimulation with 1.0 mA was delivered at those acupoints corresponding to Zusanli(ST36) and Sanyinjiao(SP6) in man via needles for 30min. Results : EA analgesia was reduced by intra-peritoneal injection at a higher dose of BAPTA from termination of EA stimulation. At 60 min after EA treatment, the total number of c-fos-immunostained neurons in each regions of the dorsal horn in the $L_{4-5}$ segments was decreased by BAPTA injection, especially in nucleus proprius. The mean integrated optical density (IOD) of NR1 and NR2B subunits were increased only in superficial laminae of EA-treated rats when compared with normal rats. However, the mean IOD of pNR1 was significantly decreased by BAPTA injection in both the superficial laminae and neck region and pNR2B in the superficial laminae. Western blot analyses confirmed the decreased expression of pNR1 and pNR2B. Conclusions : We concluded that intracellular calcium may well play an important role in EA analgesia by modulating the phosphorylation state of spinal NMDAR subunits.

Formulation and Quality Characteristics of Noni Beverages Mixed with Red Ginseng, Rubus Coreanus and Pomegranate Extracts (홍삼, 복분자, 석류를 첨가한 노니 혼합음료의 개발과 품질특성)

  • Kim, Eun-Mi
    • Culinary science and hospitality research
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    • v.17 no.1
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    • pp.259-269
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    • 2011
  • The purpose of this study was to investigate the physicochemical and sensory characteristics of Noni beverages added with 10% of water(Noni 90), 1% of red ginseng(NR), 4% of rubus coreanus extract(NR), 5% of pomegranate extract(NP), and 4% of rubus coreanus extract and 5% of pomegranate extract(NPR). Calories, protein and total fiber contents were increased in NR, NP and NPR. Total sugar was significantly increased in NG and NPR. Fat, cholesterol and saturated fatty acid were not detected. Ca and Na contents were increased in NG while Fe content was increased in NG, NR, and NPR pH was significantly increased in NG and NP. Sugar degree was significantly increased in NP and NPR. L and b values were decreased in NG, NP, and NR and a value was increased in NG and NR General bacteria count was 0/mL, and Coliform, E. Coli and 0157:H7 were gram(-) in all beverages. In sensory evaluation, color was increased in NPR while taste and overall quality were increased in NG, NR and NP. Sour taste, sweet taste, and flavor were not different between Noni and the mixed beverages. Texture was significantly increased in NP and NPR. Therefore, mixed Noni beverages added with red ginseng, rubus coreanus extract, and pomegranate extract were better than Noni beverage.

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Hydration and Cooking Properties of Brown Rice Scratched with a Knife (칼집을 낸 현미의 수화 및 취반 특성)

  • Kim, Jae-Young;Baek, Seung-Hwa
    • Korean Journal of Food Science and Technology
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    • v.44 no.6
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    • pp.722-727
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    • 2012
  • In order to improve the physical properties of brown rice by hydration and cooking, the amount of water absorption, hardness, reducing sugar, and minerals were measured for rice (NR), brown rice (NBR), and scratched brown rice (SBR). The amounts of water absorption were present in the order of NBR<0.07 SBR<0.20 SBR=NR after 210 min. The moisture contents of gelatinization rice were significantly different by degree of milling and scratch. The hardness of gelatinization rice were present in the order of NR<0.20 SBR<0.07 SBR

Studies on the Physical Properties and Application of EPDM-Polymer Blends. Part 6. Physical Properties for EPDM-NR-SBR Blends (EPDM과 각종(各種) Polymer의 Blend에 의(依)한 성능변화(性能變化) 및 그 응용(應用)에 관(關)한 연구(硏究)(제6보(第6報)) EPDM과 Natural Rubber 및 Butadiene-Styrene Rubber의 Blend에 대(對)하여)

  • Kim, Joon-Soo
    • Elastomers and Composites
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    • v.7 no.2
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    • pp.183-192
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    • 1972
  • As a series of tile studies of EPDM-Polymer blends, tile experiment are concentrated to the investigation of the physical properties of tile EPDM-NR-SBR blends. The results are shown as follows: 1. In blending, tensile strength decreased with increase in EPDM contents, especially the ratio of EPDM/NR-SBR is 75/25. 2. Elongation and tear strength were much influenced by blending, especially the ratio of EPDM/NR-SBR is 50/50. 3. Ozone resistance is much improved after blending. It was effective more than tile ratio of EPDM/NR-SBR is 25/75. 4. Aging resistance is much improved after blending. It was effective more than the ratio of EPDM/NR-SBR is 50/50. 5. Hardness increased with increase in EPDM contents and on the other hand, abrasion resistance decreased.

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The Study on the Properties of EPDM/NR Blends (EPDM/NR 블랜드의 물성에 관한 연구)

  • Go, Jin-Hwan;Park, Sung-Soo
    • Elastomers and Composites
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    • v.29 no.2
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    • pp.121-130
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    • 1994
  • The physical properties of rubber blend between natural rubber(NR) and ethylene propylene diene terpolymer(EPDM) were investigated as a study of EPDM composite materials. For EPDM/NR blends, the effects of ethylene and diene contents in EPDM, blend ratio, dicumyl peroxide(DCP) curing system on the physical properties, interfacial adhesion force and dynamic crack growth etc. were studied. EPDM/NR blends loaded with carbon black were prepared by mechanical mixing and cured by plate heating cure press. Crosslinking density was measured by swelling method with toluene. The physical properties of all blends were measured with Instron, fatigue to failure(FTF), Demattia flex cracking tester(DMFC), scanning electron microscopy (SEM), etc. As the ethylene and diene contents in EPDM increased, the physical properties, such as dynamic crack growth, adhesion to other component were increased too. Interfacial adhesion force of EPDM/NR blends to dissimilar layer was improved by the use of optimum peroxide curing system.

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Effects of Mold Time on Swelling of Natural Rubber Sponge by 2-Step Foaming (2단발포에서 금형시간이 천연고무 스폰지의 팽윤에 미치는 효과)

  • Lee, Hwan-Kwang
    • Proceedings of the KAIS Fall Conference
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    • pp.335-338
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    • 2008
  • 2단발포에서 금형시간이 천연고무(NR) 스폰지의 팽윤에 미치는 효과를 검토하였다. Kneader와 Rollmill을 사용하여 NR컴파운드를 제조하고 높은 압력조건의 1차금형에서 부분가교시킨 후 대기압의 2차 금형에서 발포와 가교를 완성시켰다. NR스폰지의 겉보기밀도를 측정하고 주사전자현미경을 사용하여 셀구조를 관찰하였다. 얻어진 스폰지에 대하여 실온에서 톨루엔, 이소옥탄, 항공유에 의한 팽윤거동을 조사하였다. 1차금형시간이 증가하면 NR스폰지의 겉보기밀도가 증가하고 팽윤비가 감소하였다. 2차금형시간이 증가하면 NR스폰지의 겉보기밀도가 감소하고 팽윤비가 증가하였다. 용매의 접촉에 의한 NR 스폰지의 부피팽윤비를 높이기 위하여 금형에서 동시에 발생하는 발포제의 분해반응과 NR의 가교반응을 적절히 조절하는 것이 중요하다.

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A CONCEPT UNIFYING THE ARMENDARIZ AND NI CONDITIONS

  • Chun, Young;Jeon, Young-Cheol;Kang, Sung-Kyung;Lee, Key-Nyoung;Lee, Yang
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.1
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    • pp.115-127
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    • 2011
  • We study the structure of the set of nilpotent elements in various kinds of ring and introduce the concept of NR ring as a generalization of Armendariz rings and NI rings. We determine the precise relationships between NR rings and related ring-theoretic conditions. The Kothe's conjecture is true for the class of NR rings. We examined whether several kinds of extensions preserve the NR condition. The classical right quotient ring of an NR ring is also studied under some conditions on the subset of nilpotent elements.

Verticillium dahliae toxins-induced nitric oxide production in Arabidopsis is major dependent on nitrate reductase

  • Shi, Fu-Mei;Li, Ying-Zhang
    • BMB Reports
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    • v.41 no.1
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    • pp.79-85
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    • 2008
  • The source of nitric oxide (NO) in plants is unclear and it has been reported NO can be produced by nitric oxide synthase (NOS) like enzymes and by nitrate reductase (NR). Here we used wild-type, Atnos1 mutant and nia1, nia2 NR-deficient mutant plants of Arabidopsis thaliana to investigate the potential source of NO production in response to Verticillium dahliae toxins (VD-toxins). The results revealed that NO production is much higher in wild-type and Atnos1 mutant than in nia1, nia2 NR-deficient mutants. The NR inhibitor had a significant effect on VD-toxins-induced NO production; whereas NOS inhibitor had a slight effect. NR activity was significantly implicated in NO production. The results indicated that as NO was induced in response to VD-toxins in Arabidopsis, the major source was the NR pathway. The production of NOS-system appeared to be secondary.

Influence of Mastication en Properties of Carbon Black-Filled NR Compounds

  • Park, Sung-Seen
    • Macromolecular Research
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    • v.8 no.2
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    • pp.73-79
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    • 2000
  • The influence of mastication of natural rubber (NR) on properties of carbon black-filled NR compounds was studied. Variations of viscosities of the masticated NR and the carbon black-filled NR compound by heating were also investigated. The viscosities of the compounds decreased by increasing the mastication time of the raw rubber. The viscosities of the masticated NR and the compounds increased by increasing the heating time. This was explained by the combination reaction between functional groups in the rubber. The viscosity increment of the masticated rubber and the compounds by heating became larger with increased mastication time. Cure rate of the compound became faster by increasing the mastication time. Modulus of the vulcanizate made of the rubber masticated for a long time was higher than that of the vulcanizate made of the rubber masticated for a short time while elongation at break of the former was shorter than that of the latter. This was explained by the content of bound rubber and chain length of the rubber molecules.

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