• 농업과학연구
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• 제46권4호
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• pp.723-735
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• 2019

The power-train is the most important component of an agricultural tractor. In this study, the strength of the driving gear transmission of an 82 kW-class tractor was analyzed using equivalent torque during plow tillage. The load measurement system consisted of an engine revolution speed sensor, torque-meters, revolution speed sensors for four axles, and pressure sensors for two hydraulic pumps. The load data were measured during plow tillage for four speed stages: F2 (2.78 km/h), F5 (5.35 km/h), F7 (7.98 km/h), and F8 (9.75 km/h). Aspects of the gear-strength such as bending stress, contact stress, and safety factors were analyzed under two torque conditions: the equivalent torque at the highest plow load for the F8 speed stage and the maximum engine torque. The simulation results using KISSsoft showed that the maximum engine torque conditions had a lower safety factor than did the highest equivalent torque condition. The bending safety factors were > 1 at all gear stages, indicating that gear breakage did not occur under actual measured operating conditions, nor under the maximum torque conditions. However, the equivalent torque condition in the contact stress safety factor was > 1, and the maximum torque condition was < 1 at the first gear pair. The method of analysis using the equivalent torque showed lower stress and higher safety factor than did the method using maximum torque. Therefore, when designing a tractor by applying actual working torque, equivalent torque method would support more reliable product development.

• 한국병원경영학회지
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• 제1권1호
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• pp.37-55
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• 1996

This study attempts to analyze the factors affecting the intention of transferring to another hospitals among radiology technologists. 344 cases were reviewed in 5 university hospitals and 1 general hospital. Self-administered questionaire were given to study the socioeconomic characteristics, working conditions, job satisfaction level, and the reasons for transfer among the technologists. The major findings were as follows : 1. Job position and hospital characteristics had a statistically significant relationship with the intention of transferring to another hospital. 2. Those who were not satisfied with their salaries and promotional opportunity showed a higher tendency towards to transfer. 3. Those who were less satisfied with the opportunity for developing the personal ability and had the negative attitude on their job showed a higher tendency to transfer. 4. Those who did not sustain good relationship with their superiors and co-workers scored high on the tendency to transfer. 5. In the result of mutiple regression, recognition of radiation hazard, job satisfaction, satisfaction with salary levels, job attitude were significantly related to transfer. The above indicate that besides economic incentives, job satisfaction and organizational culture to promote their ability and form a good relationship with organization members were very important to decrease the intention of transfer. Since these results represent only 6 hospitals from a limited area, more hospitals nationwide, especially small and medium-sized institutions where there is a high turnover rate of employment, need to be examined in order to investigate the various factors that affect the intention of transferring.

• The Journal of Advanced Prosthodontics
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• 제10권3호
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• pp.236-244
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• 2018

PURPOSE. To determine the discrepancy in monolithic zirconium dioxide crowns made with computer-aided design and computer-aided manufacturing (CAD/CAM) systems by comparing scans of silicone impressions and of master casts. MATERIALS AND METHODS. From a Cr-Co master die of a first upper left molar, 30 silicone impressions were taken. The 30 silicone impressions were scanned with the laboratory scanner, thus obtaining 30 milled monolithic yttrium stabilized zirconium dioxide (YSZD) crowns (the silicone group). They were poured and the working models were scanned, obtaining 30 milled monolithic yttrium stabilized zirconium dioxide (YSZD) crowns (the plaster group). Three predetermined points were analyzed in each side of the crown (Mesial, Distal, Vestibular and Palatal), and the marginal fit was evaluated with SEM (${\times}600$). The response variable is the discrepancy from the master model. A repeated measures ANOVA with two within subject factors was performed to study significance of main factors and interaction. RESULTS. Mean marginal discrepancy was $22.42{\pm}35.65{\mu}m$ in the silicone group and $8.94{\pm}14.69{\mu}m$ in the plaster group. The statistical analysis showed significant differences between the two groups and also among the four aspects. Interaction was also significant (P=.02). CONCLUSION. The mean marginal fit values of the two groups were within the clinically acceptable values. Significant differences were found between the groups according to the aspects studied. Various factors influenced the accuracy of digitizing, such as the design, the geometry, and the preparation guidance, as well as the texture, roughness and the color of the scanned material.

• 한국통신학회논문지
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• 제30권11B호
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• pp.689-697
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• 2005

IPv4로부터 IPv4/IPv6로의 전환 및 상호공존을 위한 처리 과정에서의 보안적인 고려는 상당히 중요한 문제이다. IPv4 네트워크와 IPv6 네트워크 사이의 이질적인 문제로 인해 기존의 IPv4 네트워크에서는 일어나지 않았던 다양한 위협이 존재한다. 본 논문에서는 지금까지 제안된 IPv4/IPv6 전환 기술에 대해 살펴보고, 전환 기술에서 나타날 수 있는 다양한 보안적인 위협에 대해서 분석을 하고, 그에 대한 대응방안에 대해 제시하였다. 6to4 전환기술에서는 DoS 및 DRDoS 공격 위협을 분석하고, 주소 무결성 검사방법을 해결책으로 제시하였다. 또, DSTM과 NAT-PT 전환 기술에서는 IPv4 주소를 할당하는 IPv4 주소 pool을 가진 서버에 대한 IPv4 주소 고갈 위협을 분석하였고, IPv4 주소 고갈 위협 문제를 해결하기 위해서 DSTM 전환 기술에서는 challenge-response 메커니즘 방안을 제시하였다.

• KSBB Journal
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• 제13권1호
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• pp.83-89
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• 1998

Cellulose로 만들어진 다공성 미립담체를 이용하여 HeLa cell을 working volume 100mL의 spinner flask에서 배양하였으며, 세포가 완전히 자란 미립담제를 계대배양하기 위하여 담체간 세포 전이 배양 방법을 시도하였다. 부유세포의 농도는 다공성 미립담체-HeLa 시스템의 경우에 담체간 세포 전이 배양에 영향을 미치는 중요한 인자로 작용하였으며, 낮은 칼슘농도의 배지인 RPMI-1640과 빠른 교반 속도를 이용하여 활성을 유지한 많은 세포가 떨어지도록 유도하였으며, 담체간 세포 전이 배양을 효과적으로 3회 이상 실시할 수 있었다. 이렇게 배양한 세포에 재 조합 Vaccinia virus를 감염하여 그 수율을 비교한 결과 T-flask에서 떼어낸 세포로 접종한 미립담체 배양과 거의 비슷한 재조합 단백질($\beta$-galactosidase) 수율을 나타내었다. Trypsin 처리 방법에 의한 미립담체 계대 배양도 경우에 따라서는 유용한 미립담체 계대 배양 방법이 될 수 있지만 실제 생산 규모에의 적용에는 공정이 복잡해지고 정확한 제어가 필요하다는 등의 문제가 있다. 따라서, 추가적인 비용이나 공정이 필요 없는 간편한 방법인 담체간 세포 전이 배양은 동물세포 배양을 이용한 유용 단백질 및 바이러스 생산 공정의 규모 증대에 매우 유용한 수단이다.

• 대한가정학회지
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• 제38권8호
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• pp.13-27
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• 2000

The background of single animal figures was originated from those northern mounted nomadic groups, which was Scythe style Culture. The art of the nomads working in the Scythian idiom was small in size and essentially decorative in intention, yet practically every object which can be associated with any unit in this group of people possesses many of the attributes essential to a real work of art. Clarity of conception, purity of form, co-ordination of rhythm and balance, and not least, an understanding and respect for the material employed were triumphantly blended by the Eurasian nomads to produce a distinctive style. In Scythian art the multitude of animal representations well illustrates the reoccupation of this nomadic people with animals in their environment. Usually only wild animals are represented. Commonly depicted are: stags and deer, lions or other large cats, eagles, birds heads (perhaps of ravens), griffins, snakes, hares, fish, goats, rams, boars, moose (elk), yak, sheep and bears. The occasional exception to the wild animal rule is domesticated horses-important because the Scythians were horse bleeders and their whole culture revolved around their dependence on the horse. The nomads had little reason to create object in honour of gods or men, but they had an instinct for beauty and the wish to surround themselves with the animal forms in which they had come to delight The Scytians tried to combine in a single rendering all the salient points of the animal they were delineating. They archived considerable success in the difficult task of showing in a single image the various and often incompatible poses assumed by a single animal in the course of its life. Zoomorphic motifs were used not simple for decorative effect, but to trim the object into amulets, with magical power to assist in hunting, and to protect the owner from harm.

• 한국사회복지학
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• 제68권4호
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• pp.25-51
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• 2016

본 연구의 목적은 사회적기업에서 근무하는 결혼이주여성의 근무경험을 탐색해보는 것이다. 이를 위해 C시 사회적기업에서 근무하는 10명의 결혼이주여성들을 심층면담하고, 근거이론 연구방법에 따라 분석하여 113개의 개념, 28개의 하위범주, 13개의 범주를 도출하였다. 분석결과 중심현상은 '존재의 부활'이었고, 핵심 범주는 '사회적기업이라는 제도적 기회와의 조우를 통해 존재의 부활을 경험하고 한국인으로서 자기의 존재를 확장시키기'이었다. 또한 사회적기업에서 근무하는 결혼이주여성의 근무경험은 편승형, 자기확장형, 동반성장형으로 분류되었으며, 상황모형이 제시되었다. 이러한 결과를 바탕으로 결혼이주여성의 사회적기업 취업과 관련된 정책적, 실천적 방안을 제시하였다.

• Advances in materials Research
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• 제1권4호
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• pp.299-310
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• 2012

This article describes the synthesis of a novel N-substituted pyrrole monomer containing an azobenzene group. The 2-[N-ethyl-N-[4-[(4-nitrophenyl) azo]-phenyl] amino] ethyl-3-chloropropionate (RedII) compound was synthesized via reaction of 4-nitro-4'-[N-ethyl-N-(2-hydroxyethyl)-amino] azobenzene (RedI) and 3-chloropropionic acid. RedII was reacted with the potassium salt of pyrrole then 2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate (Py-RedII) was prepared. Chemical polymerization of Py-RedII and copolymerization of Py-RedII with pyrrole carried out using $FeCl_3$. Poly (2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate) (PPy-RedII) was characterized by UV, IR, $^1HNMR$, $^{13}CNMR$ spectroscopies. Electropolymerization of Py-RedII and electroco-polymerization of Py-RedII and pyrrole were studied using conventional three electrodes system, Ag/AgCl reference electrode, platinum counter electrode and GC disk working electrode. Scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) were used for thermal and rheological studies. The TGA curve of PPy-RedII demonstrated a high thermal stability up to 200°C and its DSC thermogram showed two endothermic peaks at 88 and $122^{\circ}C$. The glass transition temperature of the polymer was found to be above the room temperature. Electrical conductivities of PPy-RedII and it's copolymer with pyrrole (PPy-RedII-co-Py) were studied by the four-probe method and produced conductivities of $7.5{\times}10^{-4}$ and $6.5{\times}10^{-3}Scm^{-1}$, respectively.

• 마이크로전자및패키징학회지
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• 제25권3호
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• pp.21-30
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• 2018

Driven by the recent energy saving trend, conventional silicon based power conversion modules are being replaced by modules using silicon carbide. Previous papers have focused mainly on the electrical advantages of silicon carbide semiconductors that can be used to design switching devices with much lower losses than conventional silicon based devices. However, no systematic study of their thermomechanical reliability in power conversion modules using finite element method (FEM) simulation has been presented. In this paper, silicon and silicon carbide based power devices with three-phase switching were designed and compared from the viewpoint of thermomechanical reliability. The switching loss of power conversion module was measured by the switching loss evaluation system and measured switching loss data was used for the thermal FEM simulation. Temperature and stress/strain distributions were analyzed. Finally, a thermal fatigue simulation was conducted to analyze the creep phenomenon of the joining materials. It was shown that at the working frequency of 20 kHz, the maximum temperature and stress of the power conversion module with SiC chips were reduced by 56% and 47%, respectively, compared with Si chips. In addition, the creep equivalent strain of joining material in SiC chip was reduced by 53% after thermal cycle, compared with the joining material in Si chip.

• 대한임상독성학회지
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• 제3권1호
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• pp.27-32
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• 2005

Purpose: The frequency of carbon monoxide poisoning has been decreased in the interior of the Korea. But occasionally it is occurred and the risk of exposure is high in working place so far. Because of the characteristics of gas, the detection of exposure and poisoning could be delayed and fatality is high. We should apprehend of carbon monoxide poisoning. So we would report analysis of patients with carbon monoxide poisoning. Methods: A retrospective review of CO poisoned patients visited emergency department from January 2000 to December 2004 was conducted. Results: 24 patients were enrolled. Their average of age was $37.6\pm20.9$ years old and COHb was $19.4\pm13.32\%$. The blood level of initial COHb and mental status on arrival were not correlated each other. The blood level of initial COHb and loss of consciousness were not correlated, too. Initial electrocardiography (EKG) was not correlated with cardiac enzymes such as CK-MB and troponin I. But base excess was correlated with mental status on arrival and complication such as rhabdomyolysis. Hyperbaric oxygen therapy was correlated with base excess and mental status on arrival. Conclusion: The clinical features of carbon monoxide poisoning are nonspecific. For proper diagnosis, it is important that we should consider patient's environment and take patient's history carefully. The blood level of initial COHb does not reflect severity of poisoning accurately. So We should determine the treatment of choice depending on patient's status.