• 제목/요약/키워드: SR system

검색결과 720건 처리시간 0.028초

분말사출성형체에서 Sr-페라이트 자성분말의 배향도에 미치는 첨가제의 영향 (Effect of Additives on the Orientation of Magnetic Sr-Ferrite Powders in Powder Injection Molded Compacts)

  • 조태식;정원용
    • 폴리머
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    • 제25권2호
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    • pp.240-245
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    • 2001
  • 다극 이방성 Sr-페라이트 소결자석을 제조하기 위한 자장중 분말사출성형공정에서 Sr-페라이트 자성분말의 배향도에 미치는 결합제의 첨가제 영향이 연구되었다 외부자기장의 방향에 대한 Sr-페라이트 자성분말의 배향도는 첨가제의 종류, 사출성형온도와 관련한 사출성형체의 유동성과 외부자기장의 세기에 크게 의존하였다. Paraffin wax/carnauba wax/HDPE 3성분계 결합제에 stearic acid를 첨가하면 분말사출성형체의 유동성이 향상되어 Sr-페라이트 자성분말의 배향도가 증가되었으나, silane계 커플링제를 첨가하면 성형체의 유동성이 오히려 감소되어 Sr-페라이트의 배향도가 감소되었다. 80% 이상의 Sr-페라이트 자성분말의 배향도는 사출성형체의 겉보기점도가 2500 poise (1000sec$^{-1}$)이하이고 외부자기장의 세기가 4kOe 이상인 유용한 조건에서 얻어졌다.

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Seed 첨가에 의한 Sr-Ferrite의 미세구조 제어 (Microstructure Control of Sr-Ferrite by Seed Addition)

  • 박준홍;신효순;이병교
    • 한국세라믹학회지
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    • 제32권1호
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    • pp.90-94
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    • 1995
  • In Sr-ferrite system, it has been attempted to inhibit the abnormal grian growth using Sr-ferrite powders synthesized by molten salt method as the matrix and the seeds, respectively. At each sintering temperature, the addition of seed more than 15% suppressed the abnormal grain growth, and the uniform microstructure resulted. Particularly, at 12$25^{\circ}C$, it was observed that the maximum number of the abnormal grain growth nuclei was achieved since the abnormal grain growth was suppressed even by the addition of 10% seed.

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Telcordia SR-332를 이용한 가전제품 신뢰도 예측 (Reliability Prediction using Telcordia SR-332 in Electric Home Appliance)

  • 이덕규
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제5권4호
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    • pp.427-438
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    • 2005
  • This paper is concerned with the problem in predicting the reliability of an LCD product, Product reliability calculation methods classify accelerated life test (ALT) and using the reliability standard as MIL-HDBK-217F and Telcordia SR-332. The reliability standard can calculate estimating value more quickly than accelerated life test. The system MTBF was calculated in accordance of Telcordia SR-332 standard which includes directions of part electronic measurement, temperature rise and environmental test data. This research is intended to obtain the useful information for each electric design step to save time and cost.

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pH와 이온강도가 나트륨-운모를 이용한 방사성 핵종 흡착제거에 미치는 영향 (Effect of pH and ionic strength on the removal of radionuclide by Na-mica)

  • 설빛나;조윤철
    • 상하수도학회지
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    • 제28권1호
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    • pp.83-89
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    • 2014
  • The aim of this study is to investigate the sorption/ion exchange of radioactive nuclides such as $Cs^+$ and $Sr^{2+}$ by synthetic Na-micas. In order to prepare Na-micas, two natural micas (phlogopite and biotite) were used as precursor materials. XRD, SEM, and EDS analyses were used to examine material characterization of synthetic Na-micas. Analyses of materials revealed that Na-micas were successfully obtained from natrual micas by K removal treatment. On the other hand, single solute (Cs or Sr) and bi-solute (Cs/Sr) sorption experiments were carried out to determine sorption capacity of Na-micas for Cs and Sr under different pH and ionic strength conditions. Uptake of Cs and Sr by micas in bi-solute system was lower than in single-solute system. Additionally, Langmuir and Langmuir competitive models were applied to describe sorption isotherm of Na-micas. bi-solute system was well described by Langmuir competitive models. For the results obtained in this study, Na-micas could be promising sorbents to treat multi-radioactive species from water and groundwater.

Small RNA biology is systems biology

  • Jost, Daniel;Nowojewski, Andrzej;Levine, Erel
    • BMB Reports
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    • 제44권1호
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    • pp.11-21
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    • 2011
  • During the last decade small regulatory RNA (srRNA) emerged as central players in the regulation of gene expression in all kingdoms of life. Multiple pathways for srRNA biogenesis and diverse mechanisms of gene regulation may indicate that srRNA regulation evolved independently multiple times. However, small RNA pathways share numerous properties, including the ability of a single srRNA to regulate multiple targets. Some of the mechanisms of gene regulation by srRNAs have significant effect on the abundance of free srRNAs that are ready to interact with new targets. This results in indirect interactions among seemingly unrelated genes, as well as in a crosstalk between different srRNA pathways. Here we briefly review and compare the major srRNA pathways, and argue that the impact of srRNA is always at the system level. We demonstrate how a simple mathematical model can ease the discussion of governing principles. To demonstrate these points we review a few examples from bacteria and animals.

Scrophulariae Radix Aqueous Extracts Ameliorate the Pressure Overloaded Heart Failure by Transverse Aortic Constriction in Mice

  • Woo, Seong-jin;Baek, Kyung-min;Jang, Woo-seok
    • 대한한방내과학회지
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    • 제39권4호
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    • pp.624-636
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    • 2018
  • Objectives: The purpose of this study was to investigate the cardioprotective effect of the potent antioxidant properties of Scrophulariae Radix (SR) aqueous extracts by examining pressure overload (PO) heart failure (HF) induced by transverse aortic constriction (TAC) of C57BL/6 mice. Methods: SR (500, 250, 125 mg/kg) and resveratrol (10 mg/kg) were administered orally once a day for 14 days, after the TAC operation. Changes in mortality, the body and heart weights, histopathology of the heart, and antioxidant defense system of the heart were analyzed. Results: After the TAC operation, increases were observed in mortality, heart weights, left ventricular hypertrophy, and lytic and focal fibrotic histological change, and destruction of the heart antioxidant defense system. However, the HF signs showed dose-dependent inhibition following 14 days of continuous oral treatment with SR. A SR dose of 125 mg/kg gave a similar inhibition to that obtained with resveratrol at 10 mg/kg. Conclusions: Oral administration of SR beneficially improves PO-induced HF following TAC surgery by increasing the activity of the heart antioxidant defense system. The overall effect of SR at 125 mg/kg is similar to the effect of resveratrol at 10 mg/kg. However, more detailed mechanistic studies should be performed by screening of the biologically active compounds in SR.

LSGM 전해질과 LSM 양극의 합성분말을 이용한 SOFC 단위전지의 특성 (Cell Properties for SOFC Using Synthesized Powder of Electrolyte LSGM System and Cathode LSM System)

  • 이미재;남중희;최병현
    • 한국세라믹학회지
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    • 제39권4호
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    • pp.359-366
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    • 2002
  • 고체산화물 연료전지의 운전온도를 낮추기 위해 구성재 중 LSGM 전해질과 LSM 양극을 합성하고, 그 특성을 조사한 후 최적 조성과 공정으로 단위전지를 제작하고 출력을 측정하였다. 전해질 조성인 $(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}와 (La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$$1500^{\circ}$에서 6시간 소결한 경우 두 조성 모두 $LaGaO_3$의 단일상을 형성하였고, $10∼3{\mu}m$의 결정 크기를 갖는 치밀한 미세구조를 얻었으며, 저기전도도는 $800^{\circ}$에서 0.13S/cm를 나타내었다. 양극의 경우 GNP법으로 $(La1-xSrx)MnO_3$를 합성한 경우 Sr의 양이 0.2mole일 때까지는 $LaMnO_3$ perovskite 단일상이 생성되었으며, 입자의 크기는 약 40nm였다. 단위전지는 $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ 조성으로 소결한 전해질 양면에 $(La_{0.9}Sr_{0.1})MnO_3$ 양극과 음극의 입자크기는 $1{\mu}m$ 정도였고 다공성을 나타내었다. 이때 단위전지의 출력은 $800^{\circ}$에서 약 $0.3W/cm^2$를 나타내었다

부활성제에 따른 SrS:Cu,X 박막 전계발광소자의 발광 특성 (Luminescent Characteristics of SrS:Cu,X Thin-Film Electroluminescent(TFEL) Deviecs depending on Coactivatiors)

  • 이순석;류창근;임성규
    • 대한전자공학회논문지SD
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    • 제37권1호
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    • pp.29-35
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    • 2000
  • 전자빔 증착 장비를 이용하여 SrS:Cu,X TFEL 소자를 제작한 후, 발광 특성을 분석하였다. 형광체 모체는 SrS 분말을 사용하였고 발광 중심체로는 Cu, $CuF_2,\;Cu_2S$ 또는 CuCl 등의 미분말을 사용하였다. SrS:Cu,X TFEL 소자의 발광 특성은 부활성제에 따라 매우 많은 변화를 나타내었다. SrS:$Cu_2$ TFEL 소자의 휘도($L_{40}$)와 효율 (${\eta}_{20}$)은 각각 1443 cd/$m^2$와 2.44 lm/w를 나타내었고, 녹색 빛의 발광 효율은 ZnS:Tb TFEL 소자보다 높아 새로운 녹색 형광체로의 활용이 기대되었다. SrS:CuCl TFEL 소자의 휘도($L_{40}$)와 효율(${\eta}_{20}$)은 각각 262 cd/$m^2$와 0.26 lm/w를 나타내었고 청색 빛을 방출하여 새로운 청색 형광체로의 활용 가능성을 확인하였다.

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유압펌프용 SRM 구동 시스템의 특성해석 (Characteristics Analysis of SRM Drive System for Hydraulic Pump)

  • 이주현;김봉철;김태형;안진우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.83-86
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    • 2005
  • This paper proposed a hydraulic pump system which uses a variable SR drive and constant capacity pump. The base and maximum speed, torque are determined from displacement capacity of the pump and maximum pressure. The drive system is set to have a minimum power consumption having hydraulic preset pressure, which is operated within a maximum capacity and maximum preset pressure. This is achieved by controlling motor speed and power with feedback signal of pressure of the hydraulic pump. A 2.2kw, 12/8-pole SR motor and DSP based digital controller are designed and prototype drive system is manufactured. The proposed variable speed SR drive system is simulated and tested with experimental set-up. The test results show that the system has some good features such as high efficiency and high response characteristics.

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도시철도차량(SR001)의 RAMS 기술 적용에 관한 연구 (A Study on the Application of RAMS Process for EMU(SR001))

  • 신건영;황홍환;장성태;이덕규;서석철;박흥수;장영봉;장주수;이희성
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.896-906
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    • 2011
  • There are lots of efforts to get more and more higher level of reliability, maintainability, availability, and safety in all the railway system development process. To do a RAMS activity and process very effectively, many an information is required based on operational knowledge and manufacturer's engineering technology together. But some interests between organization in demand sector and manufacturers in supply makes it difficult to do. This paper, for this reason, presents an idea about the activities and process for SR001 system, which is newly under developing and manufacturing by SMRT. Especially, we provide it with some idea how to integrate every activity and process and to analyze it specifically for system level as well. With these efforts, we provide a typical RAMS process of SR001 that could be applicable to other rolling stock system and the improvement of the system over total life cycle phases.

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