• 청정기술
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• 제16권4호
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• pp.297-303
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• 2010

본 연구에서는 유체유동해석프로그램인 Fluent를 이용하여 연료극 지지채식 관형 고체산화물 연료전지(SOFC)에서의 연결재 구조에 따른 성능 변화를 고찰하였다. 실험적 사실과 부합되는 이론적 결과를 확보하기 위해서는 전기적으로 전극과 하나로 되어있는 연결재의 구조가 전지 성능에 어떠한 영향을 미치는지 살피는 것이 중요하다. 두께가 작은 연결재가 단전지 성능을 우수하게 하는 것으로 보아 옴(ohmic) 저항에 직결되는 연결재의 두께가 전지 성능에 있어 주요 변수임을 확인하였다. 일정 두께로 고정된 조건 하에 연결재 폭을 변화시킨 경우, 전지 성능은 상대적으로 큰 차이를 보이지 않았다. 이는 본 연구에서 고려한 SOFC의 관형 구조 특성상 연결재의 폭으로는 원주 방향으로 흘러가는 전류 경로를 효과적으로 단축시킬 수 없기 때문으로 사료된다.

• 비파괴검사학회지
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• 제27권3호
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• pp.239-245
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• 2007

A torsional guided wave mode in a tubular structure has many advantages in obtaining a higher sensitivity and lower attenuation for a defect, because it shows no dispersion characteristics and no radial displacement for a tubular structure. Many attempts have been made to excite and receive torsional guided waves by conventional piezoelectric transducers, but only a few examples are used during a practical field inspection. In this study, an array of electromagnetic acoustic transducers (EMATs) were for an excitation and reception of the torsional guided waves in a pipe was designed and fabricated. The signal patterns were analyzed based on various beam path length. The feasibility of detecting the defects was investigated through a series of experiments with artificial notches on a pipe.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.161-168
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• 2001

The use of composite members to improve the compressive strength of steel structure is a common practice these days and its efficiency has already been proved by several researches and experiments. The result of concrete filled circular tubular(CFCT) stub column tests is introduced in this paper. The main parameter of this test is the ratio of diameter to thickness of circular hollow section. From the test results, the effect of concrete filled in steel tube on the ultimate strength, the deformation capacity and initial stiffness are discussed. The purpose of this paper is to investigate the effect of various parameters and evaluate the compressive strength of confined concrete. It would contribute to a better understanding of CFT structure, further laboratory experimentations are needed for better accurate estimation on its effect.

• 한국응용곤충학회:학술대회논문집
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• 한국응용곤충학회 2002년도 합동 춘계 학술발표회
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• pp.183-183
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• 2002

• 한국발생생물학회지:발생과생식
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• 제2권1호
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• pp.75-80
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• 1998

메기 정자는 그 길이가 약 62.5 \mu m이며 구형의 핵, 짧은 중편 및 꼬리를 ㄱ진 일반적인 메기류 정자의 미세구조적 특징을 나타내었다. 정자는 대부분의 경골어류의 정자에서와 같이 첨체를 가지고 있지 않았으며 염색질은 완전치 농축되어 있었다. 핵와(nuclear fossa)는 약 0.6 \mu m 함입되어 있었고 그 속에 기부 중심립과 말단 중심립의 일부가 포함되어 있었다. 두 중심립은 140 \circ C의 각도로 배열되어 있었으며 말단 중심립에서 9개의 부수체가 언형질막을 향하여 배열되어 있었다. 미토콘드리아는 중편 세포질에서 2층 또는 3층으로 배열되어 있었으며 핵의 후반부와 꼬리의 기부를 둘러싸고 있었다. 꼬리는 축사만으로 구성되어 있었으며 lateral fins는 관찰되지 않았다. 메기 정자의 가장 큰 구조적 특징은 중편 세포질에 구성되어 있는 관구조(tubular structure)이었다. 대부분의 경골어류의 정자는 중편 세포질에 미토콘드리아만을 포함하고 있으나, 메기 정자에서는 중편 세포질의 전반부에 미토콘드리아가 포함되어 있고, 후반부에는 소관이 모여 망상구조를 형성하는 관구조가 잘 발달되어 있었다. 이와 같은 관구조는 현재까지 Characiformes의 정자 이외의 다른 경골어류에서는 보고된 바 없으며 이러한 구조는Characiformes과 메기류의 계통학적 관계를 연구하는데 매우 중요한 형질로 여겨진다. ^u The spermatozoa of Silurus asotus are appoximately 62.5 \mu m in length and relatively simple cells composed of spherical head, a short midpiece and a tail as in most Siluriformes. The ultrastructure of the spermatozoa of S. asotus is characterized by the following features. The nucleus measuring about 1.5 \mu m in length is depressed with a deep nuclear fossa of about 0.6 \mu m in length, two fifth of the nuclear diameter. The fossa contains the proximal centriole and the half of the distal centriole. Two centrioles form an angle of approximately 140 \circ to each other. the nine satellite rays radiate from the outer surface of the distal centriole. the mitochondrea surround the basal nucleus and the axoneme, and are arranged in two or three layers in the postnuclear cytoplasm. The lateral fins are lost in the sperm tail. The most significant feature is manifested in the midpiece. The midpece comprises two parts, the mitochondria and the tubular structure unlike other teleost fishes containing only the mitochondria. The tubular structure was reported only in the spermatozoa of Citharinus belonging to the characiformes of teleost fishes. Thus it is considered to be a good characteristics for the study of phylogenetic link between Siluriformes and Characiformes.

• Applied Microscopy
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• 제46권1호
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• pp.51-57
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• 2016

The histology and anatomy of the olfactory organ in Luciogobius guttatus was investigated using a light microscopy and scanning electron microscopy. The paired olfactory organs in the dorsal part of the snout are situated in between the upper lip and the eyes. They consist of two nostrils, one anterior and the other posterior openings, and a single olfactory cavity. The anterior nostril, an incurrent opening, forms a short tubular structure from the skin. The posterior nostril, an excurrent opening, forms a circular structure opened to the exterior. The distributional pattern of the sensory epithelium is a continuous type. The sensory epithelium with numerous-motile cilia is made up of receptor cells, supporting cells, basal cells, and mucous cells. In contrast, the non-sensory epithelium is comprised of stratified epithelial cells and two types of mucous cells, acidic and neutral cells. The cilia number of the receptor cell is in range of 3 to 4 units. Such results in L. guttatus may reflect its ecological habit and microhabitat in the tidal zone with a periodic tide.

• 한국의상디자인학회지
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• 제19권4호
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• pp.1-15
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• 2017

The aim of this study is to plan a design that satisfies consumer needs by forecasting future properties following changes of gauge in basic Jacquard structure and to provide helpful data for a variety of knit-wear development. Four basic Jacquard knit samples (Normal Jacquard, Bird's eye Jacquard, Floating Jacquard, Tubular Jacquard) were selected and projected by using three types of gauges (7G, 12G, 14G) with an SES-122S type Computer Knitting machine of Shimaseiki MFG. Twelve different types of samples with Jacquards and gauges were tested on a flat table by measuring the course and wale in a 1cm area to calculate the gauge of samples. The mechanical properties of 12 types of Jacquard samples were measured using KES-FB (Kawabata Evaluation System for Fabric, Kata Tech Co. Ltd). As the result of comparing the number of patterns, courses and wales depending on the change of gauge of the basic Jacquard structure, it was observed that the number of patterns per specific length, course and wale has increased from 7G to 14G, a high-gauge. According to objective research regarding Jacquard structure, 7G Tubular Jacquard, which is low gauge, seems to be suitable for masculine design as it is heavy and thick, and has rigid and rough texture due to a high level of flexural strength and shear property. 14G Floating Jacquard, which is high gauge, seems to be suitable for feminine, silhouette design as it is light, thin, soft, flexible and has high drape. The result of this study provides a theoretical foundation for knit-wear development considering basic Jacquard structure and gauge-specific properties. This study can be used to provided directions for the development of knit industry.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.973-981
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• 2008

This document presents the JES(Joint Element Structure) method that has been adopted for the firs time in our country for the construction of the structure crossing under the railroad without open excavation. Front Jacking Method, Tubular Roof Construction Method, New Tubular Roof Method and Joint Element Structure Method are commonly used for the construction of structures crossing under the railroad. JES Method, frequently used in Japan recently, is a new method to construct the structures crossing under the railroad in a safe manner and in a relatively short period of time by utilizing the steel elements with the joints through which the load in the vertical angle to the axial direction is transferred to the next element. The elements are tied to each other through the joints to form the permanent walls of a Rahmen structure under the road without open excavation and without limitation to the length in a convenient way. Through the case study in the project of a Subway Box Culvert Improvement for the Gyeonguiseon Railroad in front of Yonsei University using the JES Method, the cost and period of construction in various types of soil is investigated compared to the Front Jacking Method. Furthermore, by analyzing the results of instrumentation measurements carried out throughout the construction, comparison between the actual displacement in the ground and the predicted displacement in the design is made to provide the considerations to be counted for the design. In conclusion, comparison in the field of economic feasibility, constructability and safety between the JES Method and Front Jacking Method, which is most frequently adopted in our country at present, is made to present the JES Method as a new alternative for the non-open excavation construction method for the structures crossing under the railway.

• Steel and Composite Structures
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• 제2권3호
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• pp.209-222
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• 2002

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.

• 대한조선학회논문집
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• 제41권6호
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• pp.56-64
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• 2004

Several types of steel structures which are employed in offshore petroleum activities are constructed with tubular members. These structures are usually subjected to various types of loads such as normal functional loads and environmental loads. Furthermore, accidental loads may also act on the leg or bracing members due to supply boat collisions and objects droppings from platform decks. The extent of damage caused by these loads ranges from total collapse of the structure to small damage which may not have serious consequence at the time of accident. To make optimal design decisions regarding structural safety and economical efficiency, it is very important to be able to assess the influence of damages on the performance of damaged structural members. In the End report, a series of calculations is performed to study the effects of different parameters on the load carrying capacity of such damaged members under pure bending. And the results of analysis are compared with experiment results.