• 한국자기학회지
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• 제2권2호
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• pp.140-144
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• 1992

강자계 내에서 영구자석의 자화량은 변한다. 따라서 영구자석을 포함하는 자기 시스템의 정확한 해석을 위해서는 영구자석의 자화량의 변화를 고려해 주어야 한다. 그런데 영구자석의 자화량 은 히스테리시스 특성을 가지고 변하므로 단순한 수식으로 표현이 되지 않으므로 종래의 방법으로는 수치모사가 불가능하다. 본 논문에서는 Preisach 모델과 결합된 유한요소법으로 히스테리시스 특성을 갖는 영구자석의 자화량을 수치모사하였다. 보자력과 잔류자속밀도 값이 다른 두 자석을 서로 접근시 킬 때 작용하는 힘을 본 방법으로 계산한 값과 strain gauge type load cell로 측정한 값이 잘 일치 함을 보임으로써, 본 방법이 자화량의 변화가 발생되는 영구자석기기의 해석에 적합함을 보였다.

• 대한치과의사협회지
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• 제49권3호
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• pp.136-145
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• 2011

Oral cavity cancer accounts for approximately 3-4% of all malignancies and is a significant worldwide health problem. The Korea Central Cancer Registry estimates that there will be approximately 1500 new cases of oral cancer in Korea. Oral cancer occurs most commonly in middle-aged and elderly individuals. The majority of oral malignancies occur as squamous cell carcinomas and despite remarkable advances in treatment modalities, the 5-year survival rate has not significantly improved over the past several decades, hovering at about 50% to 60%. The unfavorable 5-year survival rate may be attributable to several factors. First, oral cancer is often diagnosed at a late stage, with late stage 5-year survival rates as low as 22%. Additionally, the development of secondary primary tumors in patients with early stage disease has a major impact on survival. The early detection of oral cancer and premalignant lesions offers the promise to cure chance of oral cancer. The major diagnostics moddalities for oral cancer include oral cavity examination, supravital staining, oral cytology, and optical detection systems. But the clinical finding of oral mucosa is the most important key to confirm the oral cancer until now. The traditional clinical examination of oral cavity can be performed quickly, is without additional diagnostic expense to patients, and may be performed by health care professionals. Therefore, clinicians must be well-acquainted with clinical characteristics of oral cancer and practice routine screening for oral cancer in dental clinic to decrease the morbidity and mortality of disease.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권2호
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• pp.93-101
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• 2003

Scan design is a structured design-for-testability technique in which flip-flops are re-designed so that the flip-flops are chained in shift registers. The scan design cannot be used in a design with scan design rule violations without modifying the design. The most important scan design rule is concerning clock and reset signals to pins of the flip-flops or scan cells. Clock and Reset pins of every scan cell must be controllable from top-level ports. We propose a new technique to re-design gated clocks and resets which violate the scan design rule concerning the clock and reset pins. This technique substitutes synchronous sequential circuits for gated clock and reset designs, which removes the clock and reset rule violations and improves fault coverage of the design. The fault coverage is improved from $90.48\%$ to $100.00\%$, from $92.31\%$ to $100.00\%$, from $95.45\%$ to $100.00\%$, from $97.50\%$ to $100.00\%$ in a design with gated clocks and resets.

• The Korean Journal of Pain
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• 제6권1호
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• pp.100-104
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• 1993

Malignant tumors of the paranasal sinuses are quite rare entity, with maxillary neoplasms accounting for less than 1 percent of all head and neck malignancies. When considering the paranasal sinuses alone, 77 percent of cancers arise in the maxillary sinuses. There is no situation more frustrating than the management of the patients with chronic facial pain due to cancer. The initial step in managing patients with cancer pain is the use of oncologic therapy in the form of radiotherapy, surgery, chemotherapy, alone or combined, either to effect a cure or decrease the size of the tumor and thus decrease or eliminate the pain. When oncologic therapy is ineffective in providing relief, the pain must be treated by one or more of the followings: Systemic analgesics and adjuvant drugs, psychologic techniques of analgesia, neurostimulating techniques, neuroablative surgical procedures, regional analgesia with local anesthetics or neurolytic blocks. An 82-year old patient had severe pain of the orbital and infraorbital region due to squamous cell carcinoma of the maxillary sinus. We successfully treated this patient with the percutaneous retrogasserian ethanol gangliolysis by a H$\ddot{a}$rtel approach, and the analgesia lasts until the death of the patient.

• The Korean Journal of Pain
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• 제7권1호
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• pp.92-95
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• 1994

Most neoplasm of the floor of the mouth are squamous cell carcinoma. They originate from anterior midline floor of the mouth and penetrate into the sublingual gland. Invasion of the mandible is a late manifestation. Lymphatic spread is the submaxillary and subdigastric nodes and advanced lesions of them produce severe pain, The initial step in managing patients with cancer pain is the oncology therapy in the form of radiotherapy, surgery, or chemotherapy, alone or combined. When oncologic therapy is ineffective, the pain must be treated by systemic analgesic, psychologic, neurostimulating, regional analgesic,and meuroablative techniques. We successfully treated with gasserian ganglion block on the left side and mandibular nerve block on the right side with pure alcohol in the patient having severe submandibular, lower lip and tongue pain.

• 전기학회논문지
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• 제63권1호
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• pp.85-91
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• 2014

As RFID is utilized more frequently and diversely in terms of its application areas, the application of mobile RFID technology, which integrates cellular networks and RFID, is highly anticipated. The growth and development of the RFID field has bolstered the development of mobile RFID chips to be embedded in mobile phones. Because mobile RFID chips are embedded in cell phones, limitations such as low power, small form factor, and costliness must be confronted. This study presents the design of a RFID digital baseband processor that is suitable for mobile readers. The RF analog component, which affects the baseband signals, is designed separately, in consideration of the limitations stated above. The function of the baseband processor was verified through simulations and prototyped using FPGA. The power consumption of the chip is 20mW under a 20MHz clock and the chip measures $3mm{\times}3mm$.

• Geomechanics and Engineering
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• 제19권2호
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• pp.193-199
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• 2019

A frozen fringe plays a key role in frost heave development in soils. Previous studies have focused on the physical and mechanical properties of the frozen fringe, such as overall hydraulic conductivity, water content and pore pressure. It has been proposed that the thickness of the frozen fringe controls frost heave behavior, but this effect has not been thoroughly evaluated. This study used a temperature-controllable cell to investigate the impact of frozen fringe thickness on the characteristics of frost heave. A series of laboratory tests was performed with various temperature boundary conditions and specimen heights, revealing that: (1) the amount and rate of development of frost heave are dependent on the frozen fringe thickness; (2) the thicker the frozen fringe, the thinner the resulting ice lens; and (3) care must be taken when using the frost heave ratio to characterize frost heave and evaluate frost susceptibility because the frost heave ratio is not a normalized factor but a specimen height-dependent factor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권5호
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• pp.388-393
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• 2021

At present, in Korea, due to developments in medicine and technology and an increasing mean lifespan, the expected lifetime for elderly people is increasing (at 70 years, the expected additional lifespan is 14.8 years for males and 18.3 years for females). However, among all causes of death, malignant neoplasm is ranked first for all ages. Further, the incidence rate of oral cancer tends to increase with age. Thus, oral and maxillofacial surgeons have increased opportunity to experience the 'oldest old' patients with oral cancer. Elderly patients commonly have several comorbidities, poor general condition, limited socioeconomic support, fear of various postoperative complications, and perception of short for the rest of their life. In this situation, the patient, caregiver, and surgeon often choose undergraded treatment rather than standard treatment for oral squamous cell carcinoma owing to patient age. In elderly patients with oral cancer, ablation of tumor or reconstructive surgery is challenging for surgeons. Oral and maxillofacial surgeons must evaluate carefully the patient's medical condition and make a decision regarding treatment plans after sufficient discussion with patient and caregivers. We review the literature to consider the factors involved for deciding on a treatment plan regarding surgery in elderly patients with oral cancer.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1241-1250
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• 2019

This study mainly focused on the neutronics modeling of bubbles in bubbly flow in boiling water reactors. The bubble, ring and homogenous models were used for radial void fraction distribution. Effect of the bubble and ring models on the infinite multiplication factor and two-group flux distribution was investigated by comparing with the homogenous model. Square pitch unit cell geometry was used in the calculations. In the bubble model, spherical and non-spherical bubbles at random positions, sizes and shapes were produced by Monte Carlo method. The results show that there are significant differences among the proposed models from the viewpoint of physical interaction mechanism. For the fully-developed bubbly flow, $k_{inf}$ is overestimated in the ring model by about $720{\pm}6pcm$ with respect to homogeneous model whereas underestimated in the bubble model by about $-65{\pm}9pcm$ with a standard deviation of 15 pcm. In addition, the ring model shows that the coolant must be separated into regions to properly represent the radial void distribution. Deviations in flux distributions principally occur in certain regions, such as corners. As a result, the bubble model in modeling the void fraction can be used in nuclear engineering calculations.

• 한국수소및신에너지학회논문집
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• 제30권3호
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• pp.237-242
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• 2019

In the hydrogen refueling station (HRS), it is need the pre-cooling system (PCS) to limit the inside temperature ($85^{\circ}C$) of the onboard thank (700 bar) and to charge the hydrogen at short time (within 3 minutes) to fuel cell electric vehicle (FCEV). From those safety reasons, the temperature of hydrogen gas must be controled $-33^{\circ}C$ to $-40^{\circ}C$ in PCS. The cooling test of the gaseous ($N_2$, He, $H_2$) was carried out using heat exchanger (pre-cooler) by indirect cooling and direct cooling method. It was confirmed that the temperature of hydrogen gas had below $-40^{\circ}C$ at below $-75^{\circ}C$ of chiller temperature in direct cooling.