• Journal of Korean Vacuum Science & Technology
• /
• 제6권2호
• /
• pp.62-66
• /
• 2002

Hydraulic pumps are used to control the landing wheels of aircrafts, and their proper operation is vital to plane safety It is well hewn that adhesive wear failure is a major cause of pump failure. A dual nitrogen plasma immersion ion implantation process calling for the implantation of nitrogen at two different energies and doses has been developed to enhance the surface properties of the disks in the pumps. The procedures meet the strict temperature requirement of <200$^{\circ}C$, and after the treatment, the working lifetime of the pumps increases by more than a factor of two. This experimental protocol has been adopted by the hydraulic pump factory as a standard manufacturing procedure.

• ETRI Journal
• /
• 제34권4호
• /
• pp.641-644
• /
• 2012

The problem of sinusoidal parameter estimation at two channels with common frequency in white Gaussian noise is addressed. By making use of the linear prediction property, an iterative linear least squares (LLS) algorithm for accurate frequency estimation is devised. The remaining parameters are then determined according to the LLS fit with the use of the frequency estimate. It is proven that the variance of the frequency estimate achieves Cram$\acute{e}$r-Rao lower bound at sufficiently small noise conditions.

• 한국환경과학회지
• /
• 제16권2호
• /
• pp.211-218
• /
• 2007

The objectives of this study have been carried out to investigate the solubilization of municipal sewage sludge by single and dual frequency ultrasonic pretreatment, and the methane production characteristics of pretreated sewage sludge by specific methanogenic activity test for sewage sludge reduction. The waste activated sludge was collected from thickened tank of Suyoung sewage treatment plant in Busan city, and its concentration was adjusted to 1.0% total solids. Ultrasonic frequency was varied 15, 20, 15+20 kHz, and acoustic density was used a maximum 176W/L. The dual frequency ultrasonic pretreatment was found to be more effective than single frequency ultrasonic in the solubilization rate and methane production. The $SCOD_{Cr}/TCOD_{Cr}$, rate were 15.2%, 13.9%, 17.0% with single frequency of 15 kH2, 20 kHz, dual frequency of 15+20 kHz, respectively. The application of dual frequency ultrasound for sewage sludge pretreatment can be interest for sewage treatment plants having problems in sludge treatment and disposal.

• 한국자동차공학회논문집
• /
• 제2권1호
• /
• pp.106-115
• /
• 1994

A parallel integration approach is proposed for real-time simulation of controlled mechanical systems. The proposed approach, which employs the dual-rate integration method in a parallel computing environment, is developed to deal with stiffness and high frequency characteristics of the controlled mechanical systems effectively. Numerical experiments are performed to demonstrate the effectiveness of the approach in shared memory multiprocessors, Alliant FX/8 and Alliant FX/80.

• 지역사회간호학회지
• /
• 제32권2호
• /
• pp.186-194
• /
• 2021

Purpose: This study was conducted to find out the association between dual-use of the electronic cigarette (EC) and conventional cigarette (CC) and depression among undergraduate students. Methods: The participants of this study were 225 undergraduate students who were attending two universities located in Ulsan metropolitan city. Descriptive statistics and multiple regression were conducted to analyze the data. Results: Nicotine dependence and depression were significantly higher in the dual-use group than in the single-use group. Dual-use of the EC and CC was significantly associated with depression among undergraduate students. In addition, quality of sleep was significantly associated with depression among undergraduate students. Conclusion: In order to prevent depression among undergraduate students, it is necessary to improve the awareness of the danger of dual use of the EC and CC.

• Human Ecology Research
• /
• 제51권3호
• /
• pp.355-370
• /
• 2013

The purpose of this study is to investigate the nature of work-family compatibility in the everyday experiences of dual-earner families. By comprehensively describing how dual-earner families manage daily life, this study shows their current situations. In particular, this study overcomes the limitations of previous studies using the phenomenological research methods. Previous studies partially dealt with the problems of dual-earner couples, such as the role conflict of wives and husbands. However, this study broadly demonstrates how wives and husbands as independent individuals manage their lives by working together for a living. Participants were 6 males and 6 females, who lived in Gwangju metropolitan city. Data were collected through in-depth interviews and analyzed using the method of Stevick-Colaizzi-Keen in Moustakas (1994). The results of this study display that dual-earner couples work for a living, but work is the driving force in their life. Family provides dual-earner couples with a stable life, but their stable life is possible by social support like the assistance of a mother-in-law. Dual-earner couples consider work and family as the essential axis of life, thus they give the same value on work and family. Even though dual-earner couples have a difficult time educating their children because of long working hours and coming home late, they positively combine work and family meeting the needs of self-improvement. Therefore, it is necessary to create a working environment that provides enough time for housework and childcare.

• 한국동물위생학회지
• /
• 제30권4호
• /
• pp.527-532
• /
• 2007

In present study, we described the reliability of the dual priming oligonucleotide (DPO) multiplex polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis complex (MTC) and non-Mycobacterium tuberculosis (NMT) in blood samples of the Korea native cattle, Hanwoo. Among 340 samples 22 (6.5%) were positive in using DPO multiplex PCR, 21 (6.2%) were positive in PCR. The relative agreement between 2 tests was 99.7%, and the agreement quotient (kappa), was 0.95 (excellent). In these results, we demonstrated the successful application of DPO multiplex PCR for the diagnosis of bovine tuberculosis in Hanwoo. Multiplex PCR, using DPO primers, can be useful for the simple diagnosis of bovine tuberculosis in bovine blood samples.

• Clinical and Experimental Reproductive Medicine
• /
• 제47권4호
• /
• pp.300-305
• /
• 2020

Objective: The feasibility of a gonadotropin-releasing hormone agonist (GnRHa) trigger in normal responders is still a matter of debate. The aim of this study was to compare the number of mature oocytes, the number of good-quality embryos, and the live birth rate in normal responders triggered by GnRHa alone, GnRHa and human chorionic gonadotropin (hCG; a dual trigger), and hCG alone. Methods: A retrospective cohort study was conducted at the infertility clinic of a university hospital. Data from 200 normal responders who underwent controlled ovarian hyperstimulation and intracytoplasmic sperm injection with a GnRH antagonist protocol between January 2016 and January 2017 were reviewed. The first study group consisted of patients with cycles triggered by GnRHa alone. The second study group consisted of patients with cycles triggered by both GnRHa and low-dose hCG (a dual trigger). The control group consisted of patients with cycles triggered by hCG alone. Results: The groups were comparable in terms of demographics and cycle characteristics. The numbers of total oocytes retrieved and metaphase II oocytes were similar between the groups. The total numbers of top-quality embryos were 3.2±2.9 in the GnRHa group, 4.4±3.2 in the dual-trigger group, and 2.9±2.1 in the hCG group (p=0.014). The live birth rates were 21.4%, 30.5%, and 28.2% in those groups, respectively (p=0.126). Conclusion: In normal responders, a dual-trigger approach appears superior to an hCG trigger alone with regard to the number of top-quality embryos produced. However, no clinical benefit was apparent in terms of live birth rates.

• 산업융합연구
• /
• 제18권1호
• /
• pp.87-96
• /
• 2020

본 연구는 노인의 신체이미지가 성공적 노화에 미치는 영향에서 성장 마인드셋과 희망의 이중 매개효과를 검증하는데 목적이 있다. 이를 위해 충청남도 D시, S시 및 D광역시의 노인 422명을 대상으로 설문조사하였고 수집한 자료는 SPSS 25.0과 PROCESS macro 3.4 프로그램을 활용하여, 빈도 분석, 신뢰도 분석, 상관 분석 및 부트스트랩을 통한 이중 매개 분석을 수행하였다. 연구의 결과는 다음과 같다. 첫째, 상관분석 결과 각 변인들 간에는 통계적으로 유의미한 정적 상관관계가 있었다. 둘째, 경로분석 결과 신체이미지는 성장 마인드셋과 희망에 정적 영향을 미쳤고, 성장 마인드셋은 희망과 성공적 노화에 정적인 영향을 주었으며, 희망 또한 성공적 노화에 유의미한 영향을 미쳤다. 셋째, 이중 매개효과 분석 결과 신체이미지와 성공적 노화의 관계에서 성장 마인드셋과 희망은 이중 매개하였다. 본 연구는 노인들의 성공적인 노화를 위한 신체이미지, 성장 마인드셋 및 희망을 활용한 새로운 모델과 기초자료를 제공하였다.

• Computers and Concrete
• /
• 제33권2호
• /
• pp.217-240
• /
• 2024

The purpose of this study is to propose new hysteretic characteristics of medium- to low-rise RC structures controlled by both shear and flexure. Through previous study, the dual lateral force-resisting system composed of shear and flexural failure members has a new failure mechanism that cooperates to enhance the flexural capacity of the flexural failure member even after the failure of the shear member, and the existing theoretical equation significantly underestimates the ultimate strength. In this study, the residual lateral strength mechanism of the dual lateral force-resisting system was analyzed, and, as a result, an equation for estimating the residual flexural strength of each shear-failure member was proposed. The residual flexural strength of each shear-failure member was verified in comparison with the structural testing results obtained in previous study, and the proposed residual flexural strength equation for shear-failure members was tested for reliability using FEA, and its applicable range was also determined. In addition, restoring-force characteristics for evaluating the seismic performance of the dual lateral force-resisting system (nonlinear dynamic analysis), reflecting the proposed residual flexural strength equation, were proposed. Finally, the validity of the restoring-force characteristics of RC buildings equipped with the dual lateral force-resisting system proposed in the present study was verified by performing pseudo-dynamic testing and nonlinear dynamic analysis based on the proposed restoring-force characteristics. Based on this comparative analysis, the applicability of the proposed restoring-force characteristics was verified.