• 한국압력기기공학회 논문집
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• 제17권2호
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• pp.75-82
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• 2021

The 3D printing technology is one of the fourth industrial revolution technology that drives innovation in the manufacturing process, and should be applied to nuclear industry for various purposes according to the manufacturing trend change. In nuclear industry, it can be applied to manufacture obsolete items and new designed parts in advanced reactors or small modular reactors (SMRs), replacing the traditional manufacturing technologies. A gate valve body was manufactured, which was obsolete in nuclear power plant, using DED(Directed Energy Deposition) metal 3D printing technology after restoring design characteristics including 3D design drawing by reverse engineering. The 3D printed valve body was assembled with commercial parts such as seat-ring, disk, stem, and actuator for performance test. For the valve assembly, including 3D printed valve body, several tests were performed, including pressure test, end-loading test, and seismic test according to KEPIC MGG and KEPIC MFC. In the pressure test, hydraulic pressure of 391kgf/cm² was applied to 3D printed valve body, and no leak was detected. Also the 3D printed valve assembly was performed well in end-loading and seismic tests.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.800-805
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• 2001

Both analytical and experimental studies are presented to investigate the strength of the membrane which is designed by Kogas and will be used as a sealing for a LNG tank. Kogas has already developed the Ring-Knot type membrane, but new type had yet to be developed. This paper reports on the results of investigations into this new type of membrane. Various theorical analyses using FEM and experiments are conducted on the basis of RPIS, and it is found that the RPIS is fully satisfied.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.204-207
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• 2007

DMFC(direct methanol fuel cell)는 액체연료의 이동과 저장의 용이성 때문에 이동용 장치를 위한 전원공급 장치로서 오랫동안 관심을 받아왔다. 하지만 methanol crossover는 DMFC의 상용화 이전에 해결해야 할 문제이다. 이를 위해 많은 분야에서 연구가 진행되고 있고, 그중에서 methanol에 저항성을 가진 촉매의 개발에 활발히 연구가 진행되고 있다. 본 연구에서는, 표연개질 된 PtCo/C 촉매를 사용하여 메탄올에 저항성을 가진 촉매를 합성하였다. 합성된 촉매의 size와 morphology를 알아보기 위해 transmission electron microscopy (TEM)를 사용하였다. 또한 methanol 존재 하에 산소환원반응의 activity를 알아보기 위해 Rotating ring disk electrode(RRDE) test를 하였고, MEA를 제작하여 full cell test도 병행하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.347-348
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• 2005

A proving ring test method equipped with DCPD was developed and applied to detect the crack initiation time in PWR primary water conditions. The specimens were exposed to the PWR primary water environment during one month. The DCPD signals were very clear but the crack initiation was not detected manly because of the low stress condition. To increase the stress condition, Ni plating will be conducted after the straining the specimens.

• 한국생산제조학회지
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• 제21권2호
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• pp.305-310
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• 2012

Planetary gear box is a power transmitter having very high gear ratio in compact volume. The planetary step-down gear box converts high speed and low torque into low speed and high torque, which is widely used in constructional and industrial machinery field. And, the planetary step-up gear box does vice versa working, which is used as main gear box of large sized wind mill system. The large sized planetary gear box must be performed the normal-opposite rotation test as a its durability test for achieving the reliability. The large sized planetary gear box is composed by triple gear trains of sun gear, carrier, and ring gear. If input power is supplied into one of them and the other is fixed, and then another becomes the output part. In this paper, we designed a new test equipment which can do rapid normal and opposite rotational change with only small displacement by supplying test power using the above rotation (driving) characteristics and hydraulic cylinder and link, and also compared and analyzed with existing method through various experiments.

• 대한화장품학회지
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• 제22권2호
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• pp.174-181
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• 1996

The novel synthesis of 3-aminopropyl dihydrogen phosphate(3-APPA; 3-Aminopropane phosphoric acid), and its applicability to the skin as a cosmetic raw material in terms of its efficacy and toxicology were presented. The phosphorylation of 3-amino-1-propanol was carried out via cyclization into 6-membered 2, 6-oxaza-phosphoryl ring in the presence of phosphorous oxychloried and an organic base. The subsequent ring-opening hydrolysis and crystallization afforded the highly purified product in 90% isoloated yield. The method is much superior to the previous literature phosphorylation methodsm, as the procedure is simple and high-yielding. To confirm the efficacy of 3-APPA, several activities related to anti-aging capacity were measured. In-vitro human fibroblast, linear and 3-dimensional collagen matrix culture revealed that 3-APPA stimulated the proliferation of fibroblasts, and enhanced the synthesis of collagen, which showed 3-APPA's potency for skin wrinkle reduction. The toxicolgical aspect of 3-APPA was also extensively examined. In vivo toxicity tests such as acute oral toxicity, eye irritation, human patch, and the repeat insult human patch test proved 3-APPA to be a safe material. Thus 3-APPA can be used as an effective anti-aging agent for various cosmetic formulations.

• Parasites, Hosts and Diseases
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• 제61권1호
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• pp.33-41
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• 2023

The discovery of new antimalarial drugs can be developed using asynchronized Plasmodium berghei malaria parasites in vivo in mice. Studies on a particular stage are also required to assess the effectiveness and mode of action of drugs. In this report, we used endoperoxide 6-(1,2,6,7-tetraoxaspiro [7.11] nonadec-4-yl) hexan-1-ol (N-251) as a model antimalarial compound on P. chabaudi parasites. We examined the antimalarial effect of N-251 against ring-stage- and trophozoite-stage-rich P. chabaudi parasites and asynchronized P. berghei parasites using the 4-day suppressive test. The ED₅₀ values were 27, 22, and 22 mg/kg, respectively, and the antimalarial activity of N-251 was verified in both rodent malaria parasites. To assess the stage-specific effect of N-251 in vivo, we evaluated the change of parasitemia and distribution of parasite stages using ring-stage- and trophozoite-stage-rich P. chabaudi parasites with one-day drug administration for one life cycle. We discovered that the parasitemias decreased after 13 and 9 hours post-treatment in the ring-stage- and trophozoite-stage-rich groups, respectively. Additionally, in the ring-stage-rich N-251 treated group, the ring-stage parasites hindered trophozoite parasite development. For the trophozoite-stage-rich N-251 treated group, the distribution of the trophozoite stage was maintained without a change in parasitemia until 9 hours. Because of these findings, it can be concluded that N-251 suppressed the trophozoite stage but not the ring stage. We report for the first time that N-251 specifically suppresses the trophozoite stage using P. chabaudi in mice. The results show that P. chabaudi is a reliable model for the characterization of stage-specific antimalarial effects.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.170-173
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• 2007

본 연구에서는 액체로켓엔진 내부에 라이너를 설치하고 기체 질소를 이용한 막냉각 방법을 사용하여, 라이너의 막냉각 특성을 살펴보았다. 고온 가스는 액체로켓 연소가스와 액체질소를 혼합하여 사용하였다. 기존의 액체로켓엔진 시험 설비에 추가적으로 라이너 냉각 기체를 공급 설비를 구축하였으며, 라이너 및 냉각 기체 공급부를 제작하였다. 10초 연소 실험을 통해 라이너 내부 고온 가스의 온도와 라이너 외부 벽면 온도를 측정하였으며, 기체 질소에 의한 라이너 냉각 특성을 확인하였다.

• Archives of Plastic Surgery
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• 제33권4호
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• pp.521-524
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• 2006

Purpose: The history of biometry dates back to ancient Greek. The ideal body ratio from biometry is used as a guideline in many works of art. Biometry is also used as a medical standard to determine normal or abnormal. Since the biometry of face is so complicated, many surgeons tend to regard preoperative evaluation as a bother and substitute medical records with some photographs. We introduce a new method to measure $MRD_1$ and levator function using digital photographs, which becomes widely used lately. Methods: $MRD_1$ can be measured with the primary-gaze-view photo which is magnified by PhotoshopR 7.0.1. The distance from coneal reflex of ring flash to upper eyelid margin is converted to mm-unit using the piece of ruler attached on the patient's face. Levator function can be measured with up-gaze-view photo and down-gaze-view photo which are superimposed on another. The excursion distance of upper eyelid margin (a) and the excursion distance of eyebrow (b) are measured respectively. The levator function can be assessed through subtraction of two values (a-b). This method is simple and precise and can be applied directly to patient without photos. Results: Using magnified digital photos and computer, this method can reduce personal error and instrumental error. Taking some digital photos doesn't take long time, so it can reduce the effort of preoperative evaluation and discomfort of patients. Conclusion: Digital photo-biometry is useful for retrospective study. Especially reducing personal error, it is useful when the number of specimens is huge. New levator function test is much more useful for Asian-specific eyes than Berke's method allowing frontalis muscle compensation.

• 대한전자공학회논문지
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• 제18권1호
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• pp.51-56
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• 1981

양호한 특성의 I2L 구조를 구현하기 위한 새로운 공정을 제안하였다. 이 구조에서는, extrinsic base 의 불순물 농도가 높으며, 또한 collector는 불순물 농도가 낮은 intrinsic base와 self align된다. 제안한 공정에서는 spin-on source를 확산원으로 사용하였고, mask 단계를 줄이기 위하여 열처리로 단단해진 spin-on source를 확산 mask로 사용하였다. 이 공정에 의하여 13단 ring oscil-lator를 포함한 시험소자를 6.5μm의 epi 충을 갖는 n/n+ silicon wafer 상에 제작하였다. 제작한 시험소자의 특성은, collector가 세 개인 I2L의 경우 npn transistor의 상향 전류이득은 최대치가 8이었으며, collector가 하나인 I2L의 속도전력적과 최소 전달 지연시간은 각각3.5 pJ과 50ns 이었다.