• 한국균학회지
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• 제44권3호
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• pp.132-137
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• 2016

A unrecorded hyphomycete species of Phialocephala was isolated for the first time during the investigation of fungal community in the soil samples collected from different regions of Korea. The fungal isolate was identified as Phialocephala lagerbergii, based on the morphological characteristics and phylogenetic analysis of the ribosomal DNA sequence. In addition, cultural and micro-morphological features were described in detail.

• 한국정밀공학회지
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• 제17권8호
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• pp.94-99
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• 2000

In this study applied the general controller into th 16bit ordinary controller and recommand the simulator features the real system's propeties without DSP(Digital Signal Processing)-card. This simulator is designed to be synchronized in real time using A/D(Analog-Digital) convert and D/A(Digital-Analong) convert. In this study DSP card which is usually used for complex calculation is replaced with personal computer and designed to control, control-force using with the 16-bit micro processor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.119-123
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• 2005

Mold design is a knowledge-intensive decision making process where product designer, injection molding engineer as well as mold designer affect each other. Representation and management of design knowledge is a prerequisite for an intelligent design system, which aims to guide and support designer to carry out design activity in more efficient way by avoiding or minimizing unnecessary trial and errors. This paper discusses the issues in knowledge-based mold design, and describes the structure of a knowledge-based mold design system fur parts with micro features under development.

• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.173-190
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• 2019

Steel-confined reinforced concrete (SCRC) columns feature highly complex and invisible mechanisms that make damage evaluation and pattern recognition difficult. In the present article, the prevailing acoustic emission (AE) technique was applied to monitor and evaluate the damage process of steel-confined RC columns in a quasi-static test. AE energy-based indicators, such as index of damage and relax ratio, were proposed to trace the damage progress and quantitatively evaluate the damage state. The fuzzy C-means algorithm successfully discriminated the AE data of different patterns, validity analysis guaranteed cluster accuracy, and principal component analysis simplified the datasets. A detailed statistical investigation on typical AE features was conducted to relate the clustered AE signals to micro mechanisms and the observed damage patterns, and differences between steel-confined and unconfined RC columns were compared and illustrated.

• Smart Structures and Systems
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• 제29권6호
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• pp.799-805
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• 2022

Permanent magnet synchronous motors (PMSMs) are widely used in systems requiring high control precision, efficiency, and reliability. Predicting the remaining useful life (RUL) with health monitoring of PMSMs prevents catastrophic failure and ensures reliable operation of system. In this study, a model-based method for predicting the RUL of PMSMs using phase current and vibration signals is proposed. The proposed method includes feature selection and RUL prediction based on a particle filter with a degradation model. The Paris-Erdogan model describing micro fatigue crack propagation is used as the degradation model. An experimental set-up to conduct accelerated life test, capable of monitoring various signals was designed in this study. Phase current and vibration data obtained from an accelerated life test of the PMSMs were used to verify the proposed approach. Features extracted from the data were clustered based on monotonicity and correlation clustering, respectively. The results identify the effectiveness of using the current data in predicting the RUL of PMSMs.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.177-178
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• 2006

The results of monotonic and cyclic uniaxial compression tests, in which the deviatoric component of the stress is predominant, carried out on green and recrystallized iron compacts with different levels of density are presented and discussed in order to analyse the macro and micro-mechanisms governing the mechanical behaviour of non-sintered PM materials. The plastic deformation of the particles, especially at the contact areas between neighbouring grains, produces an internal friction responsible for the main features observed in the behaviour of green metallic compacts. These results show important discrepancies with the plasticity models, Cam-Clay and Drucker-Prager Cap.

• Archives of Metallurgy and Materials
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• 제65권3호
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• pp.1005-1009
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• 2020

In this study, a non-equiatomic high entropy alloy was fabricated using the spark plasma sintering method, and its microstructural features and mechanical properties were investigated. The chemical composition of FeMnCoCr was determined by using the entropy calculation related to the design of high entropy alloys. A bulk sample with the same composition was also prepared using the conventional metallurgical processes of casting and hot rolling. The microstructures of the samples fabricated by these different processes were compared by microscope observation, and a quantitative phase analysis was carried out using FE-SEM. Hardness measurement was used to evaluate mechanical properties. Particular attention was paid to microstructural changes due to heat treatment, which was analyzed by considering how austenite stability is affected by grain refinement.

• 생명과학회지
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• 제26권6호
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• pp.705-710
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• 2016

대장암은 세계적으로 3번째로 흔한 암종이며, 암으로 인한 사망의 주요 원인이 되고 있다. 비록 다양한 진단방법이나 치료 방법이 이용되고는 있으나 병의 진행에 관여하는 분자메커니즘 이해의 부족 때문에 여전히 완전한 치료는 어려운 실정이다. 마이크로알엔에이는 단백질 정보를 코딩하고 있지 않은 작은 알엔에이 단편이다. 이러한 마이크로알엔에이는 특정 유전자의 전사과정 또는 번역과정을 조절하는 강력한 유전자 조절자로서의 기능을 가진다. 암의 발생과정에서 중요한 세포신호 전달 과정의 손상이 빈번하게 발생 하는데, 다양한 마이크로알엔에이의 이상발현이 그 원인이 되고 있다. 마이크로알엔에이-31은 암유전자의 역할을 하며 발암과정에 관여하는 다양한 유전자를 조절한다고 알려져 있다. 따라서, 본 연구에서는 대장암에서 마이크로알엔에이-31 발현의 임상적의의를 규명하고자 하였다. 175례의 대장암 조직과 16례의 정상 대장조직에서 실시간 유전자 증폭장치를 이용하여 마이크로알엔에이-31의 발현을 분석하고, 임상병리적 요인들과의 상관관계를 분석하고 임상적 유용성을 연구해 보았다. 마이크로알엔에이-31은 정상조직에 비해 대장암 조직에서 과발현이 되어 있었다. 175례 대장암 조직을 이용한 분석에서 마이크로알엔에이-31의 발현은 병기의 진행 정도에 따라 발현이 증가 되고 있었으며, 실제 마이크로알엔에이-31의 발현이 높은 대장암 환자군의 생존률이 그렇지 않은 환자군에 비해 통계적으로 유의하게 나쁜 것으로 확인 되었다. Cox 비례위험 모형과 로지스틱 회귀 모형을 이용한 분석에서 마이크로알엔에이-31의 과발현이 직접적으로 대장암 환자의 예후 및 원발전이와 연관성이 있는 것이 확인 되었다. 따라서, 이상의 연구결과를 종합해볼 때 대장암에서 과발현 된 마이크로알엔에이-31은 대장암 환자의 예후예측 및 전이예측 바이오마커로서의 활용 가능성이 높다고 볼 수 있다.

• 대한환경공학회지
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• 제27권10호
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• pp.1081-1089
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• 2005

본 연구에서는 기존에 중유를 사용하는 상용보일러에서 오리멀젼 연료의 활용 가능성을 평가하기 위하여 소형 보일러에서 오리멀젼 연료의 기본적인 연소특성을 실험과 더불어 수치해석하였다. 오리멀젼의 주요 연소특성은 최고 화염온도가 버너로부터 $20{\sim}30\;cm 뒤쪽에 나타나는 화염지연현상과 비교적 넓게 분포하는 화염의 형태로 이는 오리멀젼 제조과정에서 포함된 높은 수분함량과 미세한 수부액적으로 이한 미소폭발 현상에 기인한다. 오리멀젼 연료의 연소특성에 미치는 영향을 평가하기 위하여 연료공급량, 무화유체의 종류, 그리고 계산에 사용된 현상학적인 복사모델과 같은 중요한 설계 및 운전인자에 대한 일련의 변수연구를 수행하였다. 연소특성인 최고 화염온도 지연현상은 연료공급 속도를 조절함으로써 어느 정도 저감시킬 수 있었으며 연소생성물로 CO와 $SO_2$ 그리고 NO가스의 연소로 내 발생특성을 평가하였다. 또한 무화용 유체로 증기를 사용하였을 경우 로내 연소상태는 무화용 공기에 비해 안정화 되고 고온영역이 감소되는 결과를 보였다. 일반적으로 본 연구에서 수행한 실험조건에 대한 수치해석 결과는 물리적으로 일관성 있는 결과를 제시하였으나 오염물질 생성농도에 대한 보다 정확한 예측을 위해서는 추후 현상학적인 모델개선을 필요로 한다. 결국 본 연구로부터 개발된 컴퓨터 프로그램은 기존의 상용화 중유 보일러에서 오리멀젼 연료로 대체 사용시 개선사항 및 유용한 운전 자료를 제공할 것으로 판단된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8893-8900
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• 2014

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumor development, progression, and carcinogenesis. However, their clinical implications for gastric cancer remain elusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissues from those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNA expression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRTPCR) was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationship between altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Among a total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues from gastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193b and miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Lauren type, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression of miR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regression analysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjusted OR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patients with a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; median survival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; median survival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR-196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-change of up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a may be applied as novel and promising prognostic markers in gastric cancer.