• Nuclear Engineering and Technology
• /
• 제36권3호
• /
• pp.237-247
• /
• 2004

To investigate the applicability of automated ball indentation (ABI) tests in the evaluation of the tensile properties of cast stainless steel (CSS), ABI tests were performed on four types of unaged CSS and on 316 stainless steel, all of which had a different microstructure and strength. The reliability of ABI test data was analyzed by evaluating the data scattering of the ABI test and by comparing tensile properties obtained from the ABI test and the tensile test. The results show that the degree of scattering of the ABI test data is reasonably acceptable in comparison with that of standard tensile data, when two points data that exhibit out-of-trend are excluded from five to seven points data tested on a specimen. In addition, the scattering decreases slightly as the content of ${\delta}-ferrite$ in CSS increases. Moreover, the ABI test can directly measure the flow parameters of CSS with error bounds of about ${\pm}10\%$ for the ultimate tensile stress and the strength coefficient, and about ${\pm}15\%$ for the yield stress and the strain hardening exponent. The accuracy of the ABI test data is independent of the amount of ${\delta}-ferrite$ in the CSS.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1998년도 제28회 추계학술대회
• /
• pp.106-114
• /
• 1998

Tribological investigation of ultra thin film magnetic storage disks which have two different kinds of start/stop zone of laser textured bump disk and mechanically textured disk for before CSS test and after CSS test. To measure surface roughness, height reduction before/after CSS test and obtain accurate topographies, AFM(Atomic Force Microscope) which is most powerful recently has been used. The result of statistical analysis showed that both laser textured bump height and mechanically textured zone height have been reduced about 4~7nm after 15000 cycle CSS test. Using commercial Nano-Indenter, ramping load scratch test has been performed to investigate friction characteristic for laser textured zone and mechanically textured zone before/after CSS test.

• 대한기계학회논문집A
• /
• 제29권9호
• /
• pp.1253-1261
• /
• 2005

Cast stainless steel (CSS) is thermally aged by a long term exposure in the range of nuclear power plant operating temperature. The thermal aging is a cause of concern for the continued safe and reliable operation of CSS nuclear components. Therefore, an assessment of degradation in material properties of these components has been importantly considered. In this study the ball indentation tests were performed on four cast stainless steels aged at $400^{\circ}C$ for 3600 hours, to investigate the applicability of ball indentation test to the assessment of aging degradation of cast stainless steels. Thus, the reliability of ball indentation test for aged CSS was analyzed by evaluating the scattering of data tested from each material and by comparing tensile properties obtained from ball indentation test and standard tensile test. Also, the tensile properties of aged CSS obtained from ball indentation test were compared with those predicted by the evaluation procedure developed on the basis of material database for aged CSS.

• 대한간호학회지
• /
• 제41권2호
• /
• pp.175-181
• /
• 2011

Purpose: This study was conducted to identify endotracheal colonization and the incidence of ventilator-associated pneumonia related to the type of endotracheal suction system. Methods: The participants in this study were ICU patients hospitalized between October 2009 to March 2010 who used ventilators for over 48 hr with closed (CSS, n=30) or open (OSS, n=32) suction systems. To standardize the pre-intervention suction system, a suctioning protocol was taught to the ICU nurses. Collected data were analyzed using ${\chi}^2$-test, Fisher's exact test, Wilcoxon rank sums test, Wilcoxon test, Log-rank test and Poisson regression. Results: Endotracheal colonization was higher in OSS than CSS from day 1 to day 8 while using a ventilator and there was a significant difference between the two groups. The CSS reached 50% of endotracheal colonization by the 4th day, whereas for the OSS, it was the 2nd day (p=.04). The incidence of ventilator-associated pneumonia showed no significant difference. Conclusion: For patients with a high risk of pneumonia, CSS must be used to lower endotracheal colonization.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 춘계학술대회논문집
• /
• pp.1589-1595
• /
• 2000

레이저 텍스쳐와 미케니칼 텍스쳐 컴퓨터 하드디스크의 마찰과 마코 매카니즘이 Contact Start/Stop test 실행후의 특성들에 대해 연구되었다. 다양한 분석적이고 기계적인 테스트 기술들이 이용되었다. 형상, 조도, 화학적 조성, 기계적 성질, CSS 로부터 기인된 코팅의 마찰특성들에 대해 그 변화들을 조사하였다. 즉, AFM(Atomic Force Microscopy), Nano-Indentation, Nano-Scratch, TOF-SIMS(Time of Flight Secondary Ion Mass Spectroscopy), AES(Auger Electronic Spectroscopy)등이 이 연구에 적용되었다. 레이저 텍스쳐 범프의 표면조도와 미케니칼 텍스쳐 지역의 표면조도는 각각 대략적으로 4nm 와 7nm 감소되었다. 탄성계수와 경도값은 CSS test후에 증가하였고 가장 바깥쪽의 코팅층의 변형강화가 생겨났다. 자성층과 Ni-P 층 사이에 점착성의 문제가 확인되었다. TOF-SIMS 분석은 C 와 $C_2F_5$의 세기에 있어서 감소를 드러냈고 이것은 코팅 표면에 윤활제 요소의 마모를 확실시 할수 있는 결과로 나타났다.

• 대한간호학회지
• /
• 제51권5호
• /
• pp.525-536
• /
• 2021

Purpose: The aim of this study was to assess the Turkish adaptation of the COVID Stress Scale (CSS) on the basis of determining the stress caused by the coronavirus disease (COVID-19) pandemic, and to test its validity and reliability. Methods: The English CSS was translated into Turkish using forward and backward translation. Data were collected online from 360 participants. Construct validity was evaluated using confirmatory factor analysis, exploratory factor analysis, and content validity. Pearson product-moment correlation, Cronbach's alpha reliability coefficient, and test-retest methods were used to evaluate reliability. Results: The Turkish version of the CSS has 36 items consistent with the original scale and has five factors: COVID danger and contamination, socioeconomic consequences of COVID, COVID xenophobia, traumatic stress due to COVID, and compulsive checking for COVID. The construct validity of the Turkish version of the CSS was verified by the adjusted goodness of fit index > .85, and comparative fit index > .95. The content validity index of each item was 91%. The corrected item-total correlations of the scale ranged from .51 to .89. Internal consistency was reliable, with a Cronbach's α of .93. Conclusion: The Turkish version of the CSS is valid and reliable. It can be used as a measurement tool for the assessment of COVID-related stress.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2008년도 추계학술발표대회
• /
• pp.932-935
• /
• 2008

유비쿼터스 환경에서 '상황인식 서비스(context-aware service)'를 구현하기 위해서는 위치 정보 및 이를 기반으로 한 주변의 상황에 대한 정보, 그리고 거기에 적합한 서비스 제공 인프라를 구축하는 것이 필요하다. 본 연구에서는 최근 IEEE 802.15.4/a에서 표준화가 완료된 CSS(Chirp Spread Spectrum) 기반의 RTLS를 구축하고 성능을 평가한다.

• KSTLE International Journal
• /
• 제1권1호
• /
• pp.12-20
• /
• 2000

Nano-wear and friction of carbon overcoated laser-textured and mechanically-textured computer hard disk were characterised after contact start/stop (CSS) wear test. Various analytical and mechanical testing techniques were employed to study the changes in topography, roughness, chemical elements, mechanical properties and friction characteristics of the coating arising from the contact start/stop wear test These techniques include: the atomic force microscopy (AFM), the continuous nano-indentation test, the nano-scratch test, the time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and the auger electron spectroscopy (AES). It was shown that the surface roughness of the laser-textured (LT) bump and mechanically textured (MT) Bone was reduced approximately am and 7nm, respectively, after the CSS wear test. The elastic modulus and hardness values increased after the CSS test, indicating straining hardening of the top coating layer, A critical load was also identified fer adhesion failure between the magnetic layer and the Ni-P layer, The TOF-SIMS analysis also revealed some reduction in the intensity of C and $C_2$$F_59$, confirming the wear of lubricant elements on the coating surface.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.321-322
• /
• 2008

CSS(Chirp Spread Spectrum) technology adopt SDS-TWR algorithms of TOA(Time of Arrival) using velocity of specific medium and ToF(Time of Flight) to measure a distance, but this method always has a regular error on distance regardless of a real distance, as a result, in far distance, it decrease a error on distance relatively, but in near distance, it increase a error on distance relatively. in this paper, we propose and test new method measuring a distance more precisely in near distance using CSS and RSSI

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1997년도 제26회 추계학술대회
• /
• pp.45-50
• /
• 1997

In recent years the recording density of hard disk has been increasing largely due to the decreasing flying height of head. However, as the flying height is decreased the reliability issue becomes ever more critical. This is because the reliability and durability of hard disk is related to the head/disk interaction as the two components come into partial or full contact. In this work characteristics of friction and stiction in head/disk interface was investigated using constant speed drag test and CSS(contact-start-stop) test. The purpose of this research is to identify the frictional properties of head/disk interface