• 한국염색가공학회지
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• 제26권1호
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• pp.63-70
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• 2014

This study has attempted to figure out the effects of the surface heat of perm rods on hair. For this, after forming perm waves, hair damage and its causes have been investigated with a different hair bleach method. If hair was bleached immediately without shampooing after a perm using the heat of rods, great perm waves were formed. However, severe damage was found on the hair because of the heated rods. In addition, when hair was shampooed and dried after the perm, hair bleach was more effective. It has been confirmed that hair was damaged because of high temperature of the surface of the rods. In fact, the heated rods had a direct effect on hair damage. According to these results, it has been confirmed that heat-based perms can accelerate hair damage. Therefore, it is necessary to perform a study on the minimization of the heating of permanent tools.

• 한국패션뷰티학회지
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• 제2권1호
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• pp.14-20
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• 2004

The purpose of this Study is to provide basic data for the development of the beauty industry to meet its increased demand and liberated world markets more properly by analyzing the change of beauty environment by ages. For the Study, the literature and articles of costume and beauty, periodicals of beauty companies, and internet data were referred to review and analyze changing proceeds of beauty industries from the 1900 to the present by ages. The findings of the Study are as follows: We had the first barber shop and hairdressing salon in 1901 and 1920, respectively, after the Danbal Ryeong(A Crop Ordinance); modern education for women and active social movements resulted in change of hair styles; permanent wave tools and chemicals began to be used in the 1930s; and more people started to visit hairdressing salons after 1950s. In turn change of hair styles promoted the development of beauty technologies and the diversity of beauty tools and products. Now up-to-date instrument and products for the health of hair are developed, hairdresser provide kinder service for their customers and adjust their floor space accordingly, and, as shown in five-day workweek, are making their endeavors to improve wellbeing of their employees.

• 대한전기학회논문지:전력기술부문A
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• 제54권11호
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• pp.525-532
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• 2005

This paper presents a new two-terminal numerical algorithm for fault location estimation and for faults recognition using the synchronized phaser in time-domain. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the assumed PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. In this paper the algorithm is given and estimated using DFT(discrete Fourier Transform) and the LES(Least Error Squares Method). The algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm, the Electro-Magnetic Transient Program(EMTP/ATP) is used.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 1995년도 정기총회 및 학술발표회
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• pp.1-26
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• 1995

Key aspects of the Norwegian Method of Tunnelling (NMT) are reviewed. These include a predictive method of support design using the six-parameter Q-system of rock mass characterisation. The rock mass rating or Q-value is updated during tunnel driving. The designed tunnel support generally consists of wet process, steel fibre reinforced shotcrete combined with fully grouted, untensioned rock bolts, Even in poor rock conditions S(fr) + B usually acts as the final rock reinforcement and tunnel lining. Since it is a drained lining, it is very economic compared to cast concrete with membranes. Light, free-standing steel liners are used to prevent water affecting the runnel environment. Rock mass conditions, and hence lining design and cost estimation can be assessed by careful use of seismic surveys. Relationships between the P-wave velocity, the rock mass deformation modulus and the Q-value have recently been established, where tunnel depth, rock porosity and the uniaxial compression strength of the rock are important variables. The rock mass modulus estimate, and simple index testing of the joints, provide the key input which joints are discretely represented (either in two dimensions with the UDEC code or in three dimensions with the 3DEC code) is generally favoured compared to continuum analysis. The latter may give a misleading impression of uniformity and deformations tend to be understimated. Q-system NMT designs of S(fr) + B (fibre reinforced shotcrete and bolting) are numerically checked and adjustments made to bolt capacities and shotcrete thickness if overloading is evident around the modelled profile.

• 한국방재학회 논문집
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• 제11권2호
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• pp.171-177
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• 2011

연안 및 해안 구조물에 직접적인 파괴의 원인이 되는 지진해일 파력에 관한 연구는 그 중요성에 비해 상대적으로 크게 주목 받지 못했다. 특히, 지진해일 대피소는 지진해일 내습에 의한 파력에 안정하게 설계되어야 하며 이를 고려하기 위한 연구가 선행되어야 한다. 대부분 연구는 일본과 미국 등에서 이루어져왔으며, 일부 수치모형을 이용한 연구가 있으나 대부분은 수리모형 실험에 의존하고 있다. 이는 시간과 비용이 많이 소모되며 지진해일이 먼 거리를 전파하는 특성상 넓은 해역에 적용하기에는 곤란한 단점이 있다. 이에 본 연구에서는 기존의 2차원 수치모형을 이용하여 실제지형에서 실용적으로 지진해일 파력을 검토할 수 있는 방법에 대하여 모색하였다.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.533-540
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• 2022

This paper is the research result of designing and developing a BLDC motor for driving a condenser fan, which is widely used in air conditioners of commercial vehicles and specially equipped vehicles, and produced with a target value. The design of the motor was carried out in the order of designing the electric and magnetic circuits after determining the motor specifications. The process was repeated with different set values until the designed target condition was satisfied, and the electric and magnetic field distributions were made to be equal by reflecting the characteristics of the material. As a structural feature of the motor, it is a rotating field type composed of multipoles, and has a structure in which a permanent magnet is attached to the surface of the rotor. The manufactured BLDC motor is a 3-phase square wave driving method, with a rated voltage of 24 [V], a rotational speed of 2,500 [rpm], a rated current of 10 [A], and a power consumption of 180 [W]. A microcontroller for driving and controlling the motor was also manufactured.

• Geomechanics and Engineering
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• 제37권2호
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• pp.189-195
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• 2024

Buried pipelines can be classified as continuous and segmented pipelines. These infrastructures can be damaged either by ground movement or by seismic wave propagation during an earthquake. Permanent ground deformations (PGD) include surface faulting, liquefaction-induced lateral spreading and landslide. Liquefaction is a major problem for both superstructures and infrastructures. Buyukcekmece lake zone, which is the studied region in this paper, is a liquefaction prone area located near the North Anatolian Fault Line. It is an active fault line in Turkey and a major earthquake with a magnitude of around 7.5 is expected in this investigated region in Istanbul. It is planned to be constructed a new 12" steel natural gas pipeline from one side of the lake to the other side. In this study, this case has been examined in terms of two different support conditions. Firstly, it has been defined as a beam in liquefied soil and has built-in supports at both ends. In the other approach, this case has been modeled as a beam in liquefied soil and has vertical elastic pinned supports at both ends. These models have been examined and some solution proposals have been produced according to the obtained results. In this study, based on this sample, it is aimed to determine the behaviors of buried continuous pipelines subject to liquefaction effects in terms of buoyancy.

• 한국지반공학회논문집
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• 제30권1호
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• pp.17-25
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• 2014

해상풍력발전기의 기초는 바람, 조류, 그리고 파도 하중을 받기 때문에 해상풍력발전기 기초를 설계하는 데 있어 반복하중을 받는 기초지반의 전단거동 평가가 필요하다. 지반의 비배수 동적 전단거동은 반복하중 횟수, 수직 유효응력, 반복 전단변형률, 상대 밀도, 그리고 평균 및 반복전단응력의 조합에 영향을 받는다. 본 연구에서는 해양 실트질 모래의 비배수 동적 거동에 대한 평균 및 반복전단응력의 영향을 평가하기 위하여 반복단순전단시험(CDSS)을 수행하였으며 상대밀도 85%, 수직 유효응력 200kPa과 300kPa의 시험조건에서 15%의 이중진폭 동적전단변형률(${\gamma}_{cyc}$)과 영구전단변형률(${\gamma}_p$)를 파괴 기준으로 적용하였다. 시험결과는 설계 그래프와 등고선도로 나타내었다. 결과에 따르면 해양 실트질 모래의 비배수 동적 거동은 평균 및 반복전단응력과 두가지 전단응력의 조합에 의해 크게 변하는 경향을 보였다. 평균전단응력이 존재하는 경우에는 반복전단변형보다는 영구변형에 의해 파괴가 결정되는 것으로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.135-135
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• 2015

Tubes are of extreme importance in industries as for fluid channels or wave guides. Furthermore, some weapon systems such as cannons use the tubes as gun barrels. To increase the service life of such tubes, a protective coating must be applied to the tubes' inner surface. However, the coating methods applicable to the inner surface of the tubes are very limited due to the geometrical restriction. A small-diameter cylindrical magnetron sputtering gun can be used to deposit coating layers on the inner surface of the large-bore tubes. However, for small-bore tubes with the inner diameter of one inch (~25 mm), the magnetron sputtering method can hardly be accommodated due to the space limitation for permanent magnet assembly. In this study, a new approach to coat the inner surface of small-bore tubes with the inside diameter of one inch was developed. Instead of using permanent magnets for magnetron operation, an external electro-magnet assembly was adopted around the tube to confine the plasma and to sustain the discharge. The electro-magnet was operated in pulse mode to provide the strong axial magnetic field for the magnetron operation, which was synchronized with the negative high-voltage pulse applied to the water-cooled coaxial sputtering target installed inside the tube. By moving the electro-magnet assembly along the tube's axial direction, the inner surface of the tube could be uniformly coated. The inner-surface coating system in this study used the tube itself as the vacuum chamber. The SS-304 tube's inner diameter was 22 mm and the length was ~1 m. A water-cooled Cu tube (sputtering target) of the outer diameter of 12 mm was installed inside of the SS tube (substrate) at the axial position. The 50 mm-long electro-magnet assembly was fed by a current pulse of 250 A at the frequency and pulse width of 100 Hz and 100 usec, respectively. The calculated axial magnetic field strength at the center was ~0.6 Tesla. The central Cu tube was synchronously driven by a HiPIMS power supply at the same frequency of 100 Hz as the electro-magnet and the applied pulse voltage was -1200 V with a pulse width of 500 usec. At 150 mTorr of Ar pressure, the Cu deposition rate of ~10 nm/min could be obtained. In this talk, a new method to sputter coat the inner surface of small-bore tubes would be presented and discussed, which might have broad industrial and military application areas.

• 한국구조물진단유지관리공학회 논문집
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• 제25권3호
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• pp.68-76
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• 2021

적재설비는 지진으로 인한 막대한 손실이 발생한 사례가 있으나, 현재까지 관련 연구 및 규정이 구조요소에 비하여 상대적으로 미비한 대표적인 비구조 요소이다. 본 연구에서는 적재설비의 기둥-기초 연결부의 고정조건에 따른 외력으로 인한 적재설비의 거동특성을 실험적으로 분석하고자 하였다. 일반적으로 적재설비의 기둥-기초 연결부는 설치 기준 및 규정 없이 사용자의 편의에 따라 설치되고 있다. 이러한 이유에서 본 연구에서는 대표적인 4가지 적재설비의 기둥-기초 연결부 조건을 적용한 4가지 full-scale 적재설비를 대상으로 거동특성 분석 실험을 수행하였다. 거동특성 분석 실험은 El-Centro 지진파로 진동대를 2방향 동시 가진하며 수행하였으며, 지진하중의 크기에 따른 거동특성을 확인하기 위하여 지진파의 50% ~ 150% 까지 각 실험 별 50%씩 증가하며 진행하였다. 추가로 각 적재설비의 기초 고정조건별 고유진동수를 확인하기 위하여 공진 탐색실험을 진행하였다. 실험을 통하여 획득한 데이터 중 최상층의 변위와 실험 후 발생한 영구 변위를 각 조건별로 비교하여 적재설비의 기둥-기초 고정조건에 따른 거동특성을 분석하였다. 그 결과, 적재설비는 기초 조건의 변화에 따른 고유진동수의 변화가 미소하였으며, 입력 하중의 고유진동수의 영향보다는 적재설비 기초 고정조건의 변화로 인한 복원력 차이로 인한 영향으로 인하여 거동특성이 변화되는 것을 확인하였다.