• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.28.2-28.2
• /
• 2011

Resistance random access memory (ReRAM) is a promising candidate for next-generation nonvolatile memory because of its advantageous qualities such as simple structure, superior scalability, fast switching speed, low-power operation, and nondestructive readout. We investigated the resistive switching behavior of tantalum oxide that has been widely used in dynamic random access memories (DRAM) in the present semiconductor industry. As a result, it possesses full compatibility with the entrenched complementary metal-oxide-semiconductor processes. According to previous studies, TiN is a good oxygen reservoir. The TiN top electrode possesses the specific properties to control and modulate oxygen ion reproductively, which results in excellent resistive switching characteristics. This study presents fully room temperature fabricated the TiN/$TaO_x$/Pt devices and their electrical properties for nonvolatile memory application. In addition, we investigated the TiN electrode dependence of the electrical properties in $TaO_x$ memory devices. The devices exhibited a low operation voltage of 0.6 V as well as good endurance up to $10^5$ cycles. Moreover, the benefits of high devise yield multilevel storage possibility make them promising in the next generation nonvolatile memory applications.

• Structural Engineering and Mechanics
• /
• 제64권2호
• /
• pp.195-204
• /
• 2017

Analytical and experimental studies of the innovative pipe in pipe damper have been recently investigated by the authors. In this paper, by adding lead or zinc infill or slit diaphragm inside the inner pipe, it is tried to increase the equivalent viscous damping ratio improving the cyclic performance of the recently proposed multi-level control system. The damper consists of three main parts including the outer pipe, inner pipe and added complementary damping part. At first plastic deformations of the external pipe, then the internal pipe and particularly the added core and friction between them make the excellent multi-level damper act as an improved energy dissipation system. Several kinds of added lead or zinc infill and also different shapes of slit diaphragms are modeled inside the inner pipe and their effectiveness on hysteresis curves are investigated with nonlinear static analyses using finite element method by ABAQUS software. Results show that adding lead infill has no major effect on the damper stiffness while zinc infill and slit diaphragm increase damper stiffness sharply up to more than 10 times depending on the plate thickness and pipe diameter. Besides, metal infill increases the viscous damping ratio of dual damper ranging 6-9%. In addition, obtained hysteresis curves show that the multi-level control system as expected can reliably dissipate energy in different imposed energy levels.

• Geomechanics and Engineering
• /
• 제16권2호
• /
• pp.205-215
• /
• 2018

Strain-based criteria are known as a direct method in determining the stability of the geomechanical structures. In spite of the widely use of Sakurai critical strain criterion, it is so conservative to make use of them in rocks with initial plastic deformation on account of the considerable difference between the failure and critical strains. In this study, a new criterion has been developed on the basis of the failure strain to attain more reasonable results in determining the stability status of the tunnels excavated in the rocks mostly characterized by plastic-elastic/plastic behavior. Firstly, the stress-strain curve was obtained having conducted uniaxial compression strength tests on 91 samples of eight rock types. Then, the initial plastic deformation was omitted making use of axis translation technique and the criterion was presented allowing for the modified secant modulus and by use of the failure strain. The results depicted that the use of failure strain criterion in such rocks not only decreases the conservativeness of the critical strain criterion up to 42%, but also it determines the stability status of the tunnel more accurately.

• 한국태양에너지학회 논문집
• /
• 제36권3호
• /
• pp.25-31
• /
• 2016

Gaskets are usually used for the sealing of flange joints. The joint is usually composed of two flanges, a ring gasket and clamping bolts. The metal ring gasket is suitable for pipe flanges, pumps and valve joints in high temperature and high pressure environments. A very high surface stress is developed between a ring type joint gasket and the flange groove when the ring type joint is bolted up in a flange. The dimensions of flanges and ring joint gaskets for the pipe sizes that are in common use are specified in the ANSI codes. However, sometimes it is necessary to make a new design for the flange joint which is not specified in the codes, as the equipment is getting larger and larger in size. This paper presents the contact behavior of Class 600 ring joint gaskets with oval and octagonal cross sections. Five different sizes of gaskets are employed in the analysis, and one of them is newly designed on the basis of analysis results obtained from existing models. Three load steps are used to find the stress, stain and contact pressure etc., and to compare the contact characteristics among the models due to the bolt clamping force and the working surface pressure. ANSYS Workbench version15 is used to conduct the finite element analysis.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제53권3호
• /
• pp.399-412
• /
• 2014

The purpose of this article is to suggest using cooperative microteaching in pre-service mathematics teachers education based on their perceptions of it after actual application case. The background of this study is that cooperative learning came into the highlight as a good method to cultivate teachers' competencies for creativity and character education as well as students' creativity and character in the mathematics classroom. 20 pre-service mathematics teachers participated in their cooperative microteaching and 16 of them responded to the survey. The collected data showed that the merits of cooperative microteaching are to ease the burden of preparing for class, to discuss how to teach mathematics, to debate what lesson is better, to receive valuable feedback form their peer, and so on. Also, it provided them with the chance for self-improvement in that they kept to make up for the week points in their teaching behavior. Meanwhile, they wanted longer time to experience their teaching and their own lesson.

• 대한한방소아과학회지
• /
• 제21권1호
• /
• pp.11-26
• /
• 2007

Objectives : The purpose of this study is to investigate the recent tendency of clinical researches of obese children for finding better oriental medicine treatments. Methods : This study was focused on diagnoses, treatments, prognoses and cures of obese children based on 37 of other papers which are J Korean Oriental Med, J Korean Oriental Pediatrics, J Korean Acd Fam Med, J Korean society for the study of obesity, Korea Sport Research, J Korean Academy of Pediatric Allergy and Respiratory Disease, J Korean Society for Health Education and Promotion, Korean J Pediatric, and Korean J Oriental Physiology and Pathology. Results : The rate of obese children has been increased continuously. There are several reasons for increased rate : For example, inadequate eating habit, lack of exercise, and genetic factors such as inherited diseases, and the disorder of the endocrine system. The obesity in childhood or adolescent can cause not only the physical problems but also the mental problems. It is necessary for children to diet, change life style, exercise continuously, and being active in order to prevent child obesity and keep healthy. Obesity can be treated through therapy diet, exercise, behavior modification, drug therapy and operation. Conclusion : It is important to recognize the children obesity, and make better treatments for that in the way of oriental cure. Moreover, additional reports should be keeping up based on continuing clinical researches.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2011년도 추계학술대회
• /
• pp.727-745
• /
• 2011

Courier and logistics services such as customer contact employees (customer-contact employee) of the attitudes and behavior of the customer satisfaction level of service quality evaluation and a very big impact. In this study, using a typical customer contact employees, and to target the delivery service industry employees the organization's service orientation and customer orientation by examining the impact on the quality of companies within the organization for growth and development needs and the importance of service orientation will be trying out for. The results of this study can be summarized as follows. First, the chief executive of the organization to configure a service orientation and a detailed understanding of the factors that determine this by managing the organization to effectively come up with a way to make and ultimately the organization's service orientation, organizational culture can be positioned as effort should be taken. Second, service companies through regular training and education to maintain a certain level of service quality should be. Third, the service organization's service orientation is not a fad or a means of sustain and develop the company's survival strategy is to get out. To do this, good communication between the field and management can be achieved by a variety of channels to be established, and management's willingness to provoke sympathy for the employees should be provided.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2011년도 추계학술대회
• /
• pp.299-313
• /
• 2011

Depending on changes in industrial structure, industrial accident preventive measures have been developed in various forms. The focus for prevention of industrial accidents had been changed from part of the hardware to behavior and consciousness of workers. According to the change of focus, Korea's industrial accident preventive measures also has been adjusted to voluntary safety and health considering the safety culture and such attempts of preventive measures has contributed for reducing the accident rate. Safety culture is difficult to access due to the fact that factors that make up the safety culture are comprehensive and varied and there are many of external factors that affect to the safety culture. Moreover, there is a limit for applying specific preventive measures. Because, management culture or value of enterprises is various depending on each country or region. Nevertheless, looking at previous studies of advanced countries, they are presenting the fact that safety leadership has greater influence to formation of the safety culture. As a result, we study the Influence of manager's safety leadership that effect on safety culture. we want to propose the way to activate safety culture in workplace and to contribute for safety culture research.

• 대한가정학회지
• /
• 제26권2호
• /
• pp.29-38
• /
• 1988

The shearing properties, which belong to the mechanical properties of fabrics, are most closely related to the appearnace of weared clothes, formation and feeling of wearing. And they are the elements which show the sense of touch, the properties of drape, folds and recoveryk curve foring, and keeping up formation. Sorts of 156 commercial skil fabrics and polyester fabrics of Korean make for women's cloth were tested for shearing propreties. All samples were classified into for summer and for fall and winter wear. Then shearing properties were measured by kawabata's evluation method. In this study shear stiffness(G) and shear hysteresis (2HG, 2HG5) of shearing prperties were measurd, then G/W and 2HG/G which are concerning to formation of weared clothes and trnsformatio behavior wre properties. The results obtained are as follows: 1. Silk fabrics were higher than polyester fabrics in G and 2HG. Thickness and weight of the fabrics for summer were a third to a half of those of the fabrics for fall and winter, but shearing properties were almost the same in the two types of the fabrics. 2. Fabrics for fall and winter were lower than fabrics for summer in G/W and fabrics for summer were lower than fabrics for fall and winter in 2HG/G. 3. korean women's silk cloth was much lighter than Japanese kimono cloth in weight but thickness and shearing properties were almost the same in the two types of the clothes.

• 한국정보처리학회논문지
• /
• 제1권1호
• /
• pp.50-62
• /
• 1994

대부분의 데이터베이스 사용자 들은 폼들을 조작함으로써 데이터베이스 시스템을 사용한다. 본 논문에서는 이러한 폼들에 관한 기술 및 각 기술이 폼의 동작에 어떠한 효과를 미치는 가에 대해 논한다. 상용제품들이 지원하는 폼 시스템들을 고찰해 본 결과 어느 것도 이상적인 폼이 갖추어야 할 모든 기능을 제공하지 못한다. 본 논문에 서는 위의 상용 폼 패키지들이 갖고 있는 제한성들을 대부분 극복할 수 있는 새로운 설계방법을 제시한다. 새로운 시스템은 객체지향, 사건중심(event-driven)이며 계층 구조의 복합 블럭(composite block)을 지원한다. 또한 기본적으로 모드리스 폼을 생성 한다. 새로운 폼 시스템에서, 폼은 톱 레블의 블럭이며 블럭은 어토믹 또는 복합 구조 로 정의되는데 메소드들이 직접 함께 포함될 수 있다. 메시지들은 이와 같은 폼 객체 들 사이에서 상호 전달되어 처리된다. 새로운 시스템 하에서의 폼의 정의는 파스칼과 비슷한 문법에 의한 스크립트로써 이루어지므로 매우 간단하다.