• 센서학회지
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• 제25권3호
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• pp.208-212
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• 2016

In this work, a loop sensor for Arc-Flash detections has been developed in order to trip a circuit breaker within 2.5 ms after an Arc-Flash event. For an efficient capturing of the flash light, plastic optical fibers, where light attenuations are larger than those in silica-based ones, with different diameters and surface conditions were utilized. The performance was comparatively analyzed with those of a point sensor and a commercialized product. The point sensor module was designed for hemisphere-like capturings of Arc-Flashes larger than 3 kA at 2 meters from the sensor. On the other hand, the loop sensor allowed 360-degree-detections around the fiber axis and the measurement range was dependent on the length of the fiber connected to the sensor module. The trip-level-dependent brightness measurement results showed that the fabricated point sensor and loop sensor satisfied a brightness condition, 10~40 klux, and the responses of the system to Arc-Flashes were completed within 2.5 ms.

• Journal of Trauma and Injury
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• 제30권4호
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• pp.216-219
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• 2017

Laparoscopy has been one of the most effective modalities in various surgical situations, although its use in trauma patients has some limitations. The benefits of laparoscopy include cost-effectiveness, shorter length of hospital stay, and less postoperative pain. This report describes diagnostic laparoscopy and laparoscopic diverting sigmoid loop colostomy in penetrating extraperitoneal rectal injury. A 41-year-old male presented with perineal pain following penetrating trauma caused by a tree limb. Computed tomography showed air density in the perirectal space and retroperitoneum. As his vital signs were stable, we performed diagnostic laparoscopy and confirmed no intraperitoneal perforation. Therefore, laparoscopic diverting sigmoid loop colostomy was performed. He was discharged without any complications despite underlying hepatitis C-related cirrhosis. Colostomy closure was performed 3 months later.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.33-39
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• 2016

A ground source heat pump (GSHP) system is recommended as a heating and cooling system to solve the pending energy problem in the field of air conditioning, because it has the highest efficiency. However, higher initial construction cost works as a barrier to the promotion and dissemination of GSHP system. In this study, numerical analysis on the characteristics of high density polyethylene (HDPE) pipe with spiral inside was executed. The heat transfer and flow characteristics of it were compared with those of a conventional smooth HDPE pipe. The heat transfer coefficient and pressure drop of the spiral HDPE pipe were higher than those of the smooth HDPE pipes at the same fluid flow rate. By decreasing the flow rate, the spiral HDPE pipe represented similar values of heat transfer coefficient and pressure drop to the smooth HDPE pipe. The lower flow rate of the spiral HDPE pipe comparing with it of the smooth HDPE pipe is estimated to reduce the length of the ground loop heat exchanger.

• 한국전자파학회논문지
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• 제22권2호
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• pp.245-251
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• 2011

본 논문에서는 의사 인터디지털 계단형 임피던스 공진기(Pseudo-Interdigital Stepped Impedance Resonator: PI-SIR)와 개방 루프 링 공진기(Open-Loop Ring Resonator: OLRR)를 이용한 마이크로스트립 이중 대역 대역 통과 여파기를 제안한다. PI-SIR을 이용하여 이중 대역 여파기의 첫 번째 통과 대역과 두 번째 통과 대역을 설계하고, OLRR을 이용하여 두 번째 통과 대역 특성을 강화한다. PI-SIR 구조에서 특성 임피던스 비와 전기적 길이 비를 이용하면 첫 번째 통과 대역과 두 번째 통과 대역을 쉽고 정확하게 조정할 수 있다. 2.45 GHz와 5.8 GHz에서 동작하는 이중 대역 여파기의 설계 결과와 측정 결과로부터 제안된 여파기가 유용하다는 것을 알 수 있다.

• Journal of electromagnetic engineering and science
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• 제14권2호
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• pp.74-78
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• 2014

This paper presents a modified TEM horn that improves radiation characteristics at a low frequency region. The proposed antenna consists of an asymmetric TEM (ATEM) horn and a loop structure with an elliptical shape. The bandwidth and gain at low frequency region can be enhanced by using the ATEM horn configuration and adding a loop structure with an elliptical shape to the ATEM horn. The bandwidth of the proposed antenna is from 2.14 to over 20 GHz, whereas that of the conventional TEM horn is from 2.7 to over 20 GHz, where the dimensions of both antennas are the same except for the thickness of the loop structure. The physical and electrical dimensions of the proposed antenna are $60mm{\times}62.5mm{\times}64mm$ ($width{\times}height{\times}length$) and $0.428{\lambda}_L{\times}0.445{\lambda}_L{\times}0.456{\lambda}_L$, where ${\lambda}_L$ corresponds to the lowest frequency of the bandwidth. The realized gain of the proposed antenna is improved by 0.802 dB on average at the low frequency region (2 to 8 GHz), where the maximum gain increase is 2.932 dB when compared to a conventional TEM horn.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.2933-2938
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• 2014

전류컨베이어 회로를 이용한 주파수 고정 루프 회로를 $0.35{\mu}m$ CMOS 공정으로 설계하였다. 공급전압은 3volts를 사용하였다. 설계된 회로는 분주기, 주파수-전압 변환기, 전압 감산기 및 발진기로 구성하였으며, 각 회로 블록을 대칭적으로 배치하여 공정 변화에 따른 신뢰성 특성을 향상시켰다. HPICE 시뮬레이션 결과 MOS 트랜지스터의 채널길이, 채널 폭, 저항 및 커패시터의 크기가 ${\pm}5%$ 변화할 때 출력주파수의 변화율은 ${\pm}1%$ 내외였다.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.1-16
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• 2016

Behaviors of surges appearing near the stall stagnation boundaries in various fashions in systems of a single-stage compressor and flow-path systems were studied analytically and were tried to put to order. Deep surges, which enclose the stall point in the pressure-mass flow plane, tend to have either near-resonant surge frequencies or subharmonic ones. The subharmonic surge is a multiple-loop one containing, for example, in a (1/2) subharmonic one, a deep surge loop and a mild surge loop, the latter of which does not enclose the stall point, staying only within the stalled zone. Both loops have nearly equal time periods, respectively, resulting in a (1/2) subharmonic surge frequency as a whole. The subharmonic surges are found to appear in a narrow zone neighboring the stall stagnation boundary. In other words, they tend to appear in the final stage of the stall stagnation process. It should be emphasized further that the stall stagnation initiates fundamentally at the situation where a volume-modified reduced resonant-surge frequency becomes coincident with that for the stagnation boundary conditions, where the reduced frequency is defined by the acoustical resonance frequency in the flow-path system, the delivery flow-path length and the compressor tip speed, modified by the sectional area ratio and the effect of the stalling pressure ratio. The real surge frequency turns from the resonant frequency to either near-resonant one or subharmonic one, and finally to stagnation condition, for the large-amplitude conditions, caused by the non-linear self-excitation mechanism of the surge.

• Journal of Korean Neurosurgical Society
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• 제56권2호
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• pp.91-97
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• 2014

Objective : The purpose of this study was to evaluate demographic and clinical factors affecting the common femoral artery diameter and length, and anatomical relationship between the femoral head and the common femoral artery during angiography. Methods : We retrospectively reviewed 109 femoral angiograms. We collected the clinical data of the patients and estimated the common femoral artery diameter and length. We divided the areas in the angiogram from cephalic to caudal direction (zone 0 to 5). The lowest levels of the inferior epigastric artery loop and points of the common femoral artery bifurcation were checked. Results : The luminal diameter of the common femoral artery was $6.19{\pm}1.20mm$. Height, weight, body surface area, as well as common femoral artery diameter were significantly greater in men than in women (p<0.005). The length of the common femoral artery was $27.59{\pm}8.87mm$. Height, weight and body surface area showed strong positive relationships with common femoral artery diameter. All of the inferior epigastric artery loops were located above the center of the femoral head. The point of common femoral artery bifurcation was above the center of the femoral head in 4.59% of femoral angiograms. Conclusions : Males and patients with a high body surface area have a larger common femoral artery diameter. The cumulative probability of optimal targeting between the lowest margin of the inferior epigastric artery loop and the common femoral artery bifurcation is the highest in zone 3 puncture.

• 한국의류학회지
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• 제34권5호
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• pp.819-830
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• 2010

This study proposes medical gowns for interns and residents that address the functions of utility and activity. Based on the questionnaires, the prototype focused on the pockets for practical use and movement adaptability. Functional pockets were made by increasing pocket sizes and separating pockets with sections according to use. An inside pocket and a loop for an identification tag was placed on the chest pocket and the side seam pocket were oblique lined. To resolve horizontal stress on the back of the gown,6 cm action pleats were added at both ends of the bladebone. The elbow area was tucked up to improve the workplace activities. To reduce hamper on the gown hemline, slits were added along the gown side seam. The front button was changed into an inside button closure. The cuffs, belt, and back waist belt were removed due to occupational cases of inconvenience. The length of the sleeves was adjusted with belts to improve the movement of the arms. In accordance with design preference, the gown was designed to be knee-length with wrist length sleeves. Blue colored (2.5PB 3/12: by Munsell) material was inserted to reduce the contamination on the neck, cuffs, front closure, and hemline area. The planning cloth of the experimental gown was designed to improve activity function, cleaning, and comfort from light materials. The field test (with 30 doctors at university hospitals and the objective assessment with 9 subject groups)were done by the valuation between the existing gown and the prototype. The results showed that the prototype had to be modified by decreasing the pocket size, expanding the usage of the penholder, and simplify front pockets in order to maintain unity. The loop for the identification tag, inside pocket, and the blue colored material had to be removed. The front closure of the gown had to return to its original state.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.141-153
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• 2022

Purpose: This study aimed to identify the prevalence and extension of the anterior loop (AL) of the mental nerve in different populations and according to different cone-beam computed tomography (CBCT) imaging settings. Materials and Methods: Medline/PubMed, Embase, Scopus, Web of Science, and ProQuest were searched. The main inclusion criterion was ALs evaluated in CBCT images. The quality of studies was assessed with the Joanna Briggs Institute risk of bias checklist. Subgroup analyses were conducted for sex, side, continent, voxel size, field of view, and type of CBCT-reconstruction images with a random-effects model. Results: Sixty-three studies with 13,743 participants (27,075 hemimandibles) were included. An AL was found in 40.6% (95% CI: 32.8%-48.9%, P<0.05) of participants and 36.0% (95% CI: 27.5%-45.5%, P<0.05) of hemimandibles, in 34.9% (95% CI: 25.1%-46.2%, P<0.05) of males and 34.5% (95% CI: 23.5%-47.4%, P<0.05) of females. The average length of ALs was 2.39 mm (95% CI: 2.07-2.70 mm, P<0.05). Their extension was 2.13 mm (95% CI: 1.54-2.73 mm, P<0.05) in males and 1.85 mm (95% CI: 1.35-2.36 mm, P<0.05) in females. Significant differences were observed regarding the prevalence and length of ALs among continents and for its measured length on different CBCT-reconstruction images, but not between other subgroups. Conclusion: AL was a relatively common finding. The voxel size and fields of view of CBCT devices were adequate for assessing AL; however, a 2-mm safety margin from anatomical structures(such as the AL) could be recommended to be considered when using CBCT imaging.