• Structural Engineering and Mechanics
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• 제81권5호
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• pp.607-616
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• 2022

In this work, the free vibration problem of a rotating Rayleigh beam is solved using the meshless Petrov-Galerkin method which is a truly meshless method. The Rayleigh beam includes rotatory inertia in addition to Euler-Bernoulli beam theory. The radial basis functions, which satisfy the Kronecker delta property, are used for the interpolation. The essential boundary conditions can be easily applied with radial basis functions. The results are obtained using six nodes within a subdomain. The results accurately match with the published literature. Also, the results with Euler-Bernoulli are obtained to compare the change in higher natural frequencies with change in the slenderness ratio (${\sqrt{A_0R^2/I_0}}$). The mass and stiffness matrices are derived where we get two stiffness matrices for the node and boundary respectively. The non-dimensional form is discussed as well.

• 국제초고층학회논문집
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• 제12권2호
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• pp.137-143
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• 2023

The use of Engineered Wood Systems (EWS), especially mass-timber, as a structural alternative or complement to steel and concrete is gaining interest and acceptance across different sectors of architecture, engineering, and construction, including in high-rise buildings. Focussing on the Australian context, this study examines the levels of adoption and barriers to using timber as a primary structural material in multi-storey buildings. Data collected from semi-structured interviews with stakeholders at the forefront of adoption in structural design, construction, and property development indicates that timber in multi-storey projects in Australia still faces industry-wide challenges. Designers' awareness and attitudes towards timber adoption are generally positive and suitable for flagship projects, including tall buildings, but for enduring and widespread impact, long-term investment in education within and outside the range of stakeholders already committed to promoting timber adoption is needed.

• 한국정밀공학회지
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• 제11권6호
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• pp.127-135
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• 1994

This paper is concerned about a high speed electromagnet of Pressure control solenoid valve. Solenoid valve is controlled by means of Pulse width modulation. The magnetostatic field problem on a solenoid is numerically solved by the 2-D axisymmetric finite element method. And permeance method is adopted for analysing the static and dynamic property of solenoid part theoretically. In addition, in this study, experiments on solenoid part were performed in order to measure the magnetic force and plunger displacement. The numerical results coincided with the experimental results. As a result, the magnetic force has the linear relation with displacement of plunger and the primary factors on the performance of PWM type high speed electromagnet are coil resistance, plunger mass, and the length of air gap between plunger and core.

• Applied Microscopy
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• 제50권
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• pp.13.1-13.7
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• 2020

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of Ancistrus cirrhosus belong to Loricariidae using light and electron microscopes. The fertilized eggs formed a mass on the spawning place and were yellowish, spherical, non-transparent, demersal, adhesive, and a narrow perivitelline space. But, the adhesiveness of fertilized eggs was disappeared after spawning excluding contact parts. The micropyle with funnel shape was surrounded by 15-19 furrow lines of egg envelope in a spoke-like pattern. The outer surface of egg envelope has smooth side and inner surface of egg envelope was rough with grooves. Also, the total thickness of the fertilized egg envelope was about 32.58 ± 0.85 ㎛ (n = 20), and the fertilized egg envelope consisted of three layers, an outer adhesive electron-dense layer, a middle layer with low electron density and an inner electron-dense layer with grooves in counter structure from other most teleost. Collectively, these morphological characteristics and adhesive property of fertilized egg, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.574-581
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• 2011

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a fullsystem understanding of the radiation stress protection mechanisms of bacteria in different environments.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.990-995
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• 2012

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

• 한국식품과학회지
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• 제36권3호
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• pp.410-415
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• 2004

본 연구에서는 열풍건조를 통해 제조된 은행분말을 식품에 적응해 보고자 은행분말의 첨가수준을 달리하여 은행죽과 은행떡을 제조하고, 물리적, 관능적 특성 및 소비자 기호도 검사를 통해 바람직한 은행분말 첨가 수준을 조사하였다. 은행죽의 경우 물리적 특성 검사에서는 은행분말 첨가수준이 높아질수록 녹색도와 점도가 감소되었고, 퍼짐성이 증가되었다. 관능적 특성 중 바람직한 특성인 색의 강도와 은행향미는 은행분말 첨가량이 많아질수록 증가하였다. 소비자 기호도 검사를 한 결과, 4:6의 배합 비율로 섞인 은행죽이 전반적인 기호도와 향미 기호도에서 높은 수치를 나타냈다. 은행떡의 경우 물리적 특성 검사에서 은행분말 첨가수준이 증가할수록 녹색도와 부착성이 감소되었다. 관능적 특성 검사 결과, 은행분말 첨가수준이 높아질수록 색의 강도와 은행향미 및 가루끼는 증가하였고 경도와 덩어리 응집성은 감소하였다. 소비자 기호도 검사를한 결과, 16:84의 배합비율을 지닌 은행떡이 전반적인 기호도에서 가장 높은 경향이 나타났다. 은행의 과다 섭취에 따른 문제 가능성을 고려하면 앞으로 은행의 하루 가능 섭취량에 관한 연구 및 은행 첨가량을 줄이면서 다른 부재료의 첨가를 고려하는 연구가 지속적으로 이루어져야겠다고 본다.

• 한국음향학회지
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• 제31권8호
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• pp.561-568
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• 2012

본 연구는 등가 종 모델을 이용하여 한국종의 맥놀이 주기를 조절하는 방법을 제시한다. 한국종이 갖고 있는 미세한 비대칭성은 하나의 원주 모드를 미세한 주파수의 차이를 갖는 모드 쌍으로 분리시키는데, 이 모드 쌍의 상호간섭에 의해서 진동과 음향의 맥놀이가 발생한다. 등가 종은 축대칭 종에 등가 집중질량을 부착시킨 미소 비대칭 구조물로, 실제 종의 모드 쌍과 동일한 모드 특성을 갖는다. 등가 종 모델은 회전 쉘 이론을 근거로, 유한요소해석을 통해서 구성된다. 맥놀이 특성을 변화시키기 위하여 국부적으로 요소 두께를 감소시킬 때, 등가 종을 이용하여 맥놀이 주기를 예측한다. 예측 결과는 시험 종에 대한 실험을 통해 그 타당성을 확인한다. 본 방법은 대형 종의 맥놀이 주기 조절에 소요되는 시간을 크게 줄일 수 있을 것이다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.300-308
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• 2004

The formation mechanism of anodic oxide films on Mg alloys when anodized in NaOH solution. was investigated by focusing on the effects of anodizing potential. Al content. and anodizing time. Pure Mg and Mg-Al alloys were anodized for 10 min at various potentials in NaOH solutions. $Mg(OH)_2$ was generated by an active dissolution reaction at the surface. and the product was affected by temperature. The intensity ratio of $Mg(OH)_2$ in the XRD analysis decreased with increasing applied potential. while that of MgO increased. The anti-corrosion properties of anodized specimens at each constant potential were better than those of non-anodized specimens. The specimen anodized at an applied potential of 3 V had the best anti-corrosion property. And the intensity ratio of $Mg_{17}Al_{12}$/Mg increased with aluminum content in Mg-Al alloys. During anodizing. the active dissolution reaction occurred preferentially in ${\beta}\;phase(Mg_{17}Al_{12})$ until about 4 mins. and then the current density increased radually until 7 mins. The dissolution reaction progressed in a phase(Mg) which not formed the intermetallic compound. which had a lower Al content. In the anodic polarization test of $0.017\;mol{\cdot}dm^-3$ NaCl and $0.1\;mol{\cdot}dm^-3\;Na_2SO_4$ at 298 K. the current density of Mg-15 mass% Al alloy anodized for 10 mins increased. since the anodic film that forms on the a phase is a non-compacted film. The anodic film on the phase for 30 mins was a compact film as compared with that for 10 mins.

• 복식
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• 제52권7호
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• pp.139-154
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• 2002

This study selects mannequins. fashion models. and fashion photographs as communication media to express the beauty of an ideal body. Each medium is discussed by the denotative and connotative aspects through the semiology. First, the mannequins are the most concrete medium which can form women's ideal body types and reproduce images in which the idealistic human body are coded in various figures. It embodies such various figures of the modem society by being replaced with the symbolic representation of our intrinsic·extrinsic forms. From a denotative view, the mannequins can be explained by ideal body types and expressive tools. The mannequin has implied connotative meanings of the similarity and dissimilarity between the actual body and itself. Second, fashion models have played a role in transmitting fashion images and presenting the ideal body. As fashion has adopted the body as its object fashion models have been used to express an ideal body. The development of the mass media in the 20th century has defined the standard of the beauty, Both the relationship between fashion designers and fashion models. and the standardization of beauty and fashion models are reviewed from a denotative view. Fashion models imply connotative meanings of the figurative and the controlled property. Third, fashion photographs are historical documents presenting us with the evidence of the ideal body types and culture throughout time. The photographs could be adopted as proper means to express fashion. having realistic and practical expressional functions, and it can be said that the realistic and practical expressional function of photographs has served as a suitable means for express fashion, and fashion photographs are discussed. The fashion photograph has the reproducible and the symbolic property.