• Conservation Science in Museum
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• v.18
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• pp.19-34
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• 2017

Analysis of the species of wood in the wooden materials and the chemical composition of the fabric of the clothing excavated from the tomb of Yi Jing (1580-1642) has determined that the wooden materials, including the coffin (內棺, naegwan), burial chamber(外棺, oegwan), chilseongpan(七星板, bottom-lining board), and fan-shaped slats were made of pine(Pinus densiflora). The analysis of the fabrics suggested that the cloth attached to the fan-shaped slats, the funeral banner with inscriptions, and the five pouches for the corpse (五囊, onang) were all made of silk. The jacket was made of plain-weave cotton, while the inner and outer cloth of the socks were made of cotton and hemp, respectively. Among the silk items, the pouches for the left and right feet (constituting the five pouches for the corpse) were made from a satin-weave figured silk, while the other silk items were made of ju(紬), or plain-weave silk fabric. Infrared analysis revealed that the fan-shaped slats were decorated with cloud patterns across the entire surface, while the funeral banner and the five pouches for the corpse bore ink inscriptions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.11
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• pp.1157-1169
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• 2008

This paper presents spectral element formulation which approximates Lamb wave propagation by PZT transducers bonded on a thin plate. A two layer beam model under 2-D plane strain condition is introduced to simulate high-frequency dynamic responses induced by a piezoelectric (PZT) layer rigidly bonded on a base plate. Mindlin-Herrmann and Timoshenko beam theories are employed to represent the first symmetric and anti-symmetric Lamb wave modes on a base plate, respectively. The Euler-Bernoulli beam theory and 1-D linear piezoelectricity are used to model the electro-mechanical behavior of a PZT layer. The equations of motions of a two layer beam model are derived through Hamilton's principle. The necessary boundary conditions associated with the electro-mechanical properties of a PZT layer are formulated in the context of dual functions of a PZT layer as an actuator and a sensor. General spectral shape functions of response field and the associated boundary conditions are obtained through equations of motions converted into frequency domain. Detailed spectrum element formulation for composing the dynamic stiffness matrix of a two layer beam model is presented as well. The validity of the proposed spectral element is demonstrated through numerical examples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5384-5391
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• 2011

The computational fluid dynamics was analyzed for the pressure distribution, stream velocity distribution, stream line field, retention time and temperature distribution which are applied to the catalyst layer in the RCO reactor to derive the optimum operating condition of the heat condensing type catalytic oxidation (RCO) reactor. The results from the computational analysis revealed that the pressure loss due to the ceramic honeycomb in the catalytic bed of the reactor which is operating currently is not significant and the stream velocity (1.8~2.7 m/s) after the ceramic filter is working in stability without big channeling. To improve the stream velocity distribution of the air stream, it is necessary to extension of the connecting range between the plenum and catalytic bed inside the facility. However, the method of attaching the air stream guide vane or the perforated plate inside the reactor was not so effective.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.771-776
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• 2008

The main purpose in having a control surface on a ship is to control the motion of it. It is the important element to determine the maneuvering characteristics of the ship. In this paper, the measured results has been compared with each other to predict the performance characteristics of flapped rudder's 2-dimensional section at $Re=3.0{\times}10^4$ using 2-frame grey level cross correlation PIV method. The side force of the rudder could be mainly improved by the lift force at 10 degrees angle of attack and the drag force at 20 degrees angle of attack. The separation point and boundary layer could be controlled by the change of the only flap's angle at 10 degrees angle of attack.

• Polymer(Korea)
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• v.34 no.4
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• pp.369-375
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• 2010

We used melt polymerization method to prepare a series of aromatic liquid crystals (LCs) based on aromatic ester and amide units with the reactive methyl-maleimide end group, and then the resulting thermally cross-linked LCs to produce LC thermoset films by means of solution casting and the followed heat treatment. The synthesized LCs and LCTs were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), X-ray diffractometry (XRD), and polarizing optical microscopy (POM) with a hot stage. All of the LCs prepared by melt polymerization method formed smectic mesophases. The thermal properties of the LC and LCT films were strongly affected by the mesogen units in the main chain structures. The thermal expansion coefficients of samples were in the range of 27.72~50.95 ppm/$^{\circ}C$.

• Industry Promotion Research
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• v.4 no.2
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• pp.1-8
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• 2019

This research is a technology for cutting the insulation of the busbar (busbar) installed in the distribution panel or switchboard, the results of the study, first, the cutting unit and frame of the cutting unit including a housing attached to the upper and lower cutters, respectively Busbar coating laser cutting machine is installed on the top, characterized by consisting of a stopper for adjusting the coating cutting distance of the busbar. Second, the frame is installed with the guide bar in the longitudinal direction at the top so as to be located at the rear side end of the table, the post is installed vertically at the front and rear at the upper middle part, respectively, and cut to the table at the outer side of the front post. It is characterized by the formation of holes. Third, the supporter is fixedly installed on the upper part of the guide bar arranged in the frame, and is characterized by consisting of a cylinder and a support plate. The meaning of this study is to prevent the safety accidents of workers, to improve the efficiency of cutting work, and to prevent the occurrence of scratches on the surface of the busbar.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.35-35
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• 2019

현호색속은 양귀비과에 속하는 분류군으로서 전 세계에 약 450분류군이 분포하며 한국에는 25분류군이 분포한다. 20분류군의 한국산 현호색속 식물을 대상으로 화부 형태, 밀선의 형태, 밀선의 부착 위치를 비교 분석하였다. 현호색속 식물의 꽃은 좌우대칭하며 외화판의 거(spur)에 위치한 밀선을 갖는데 밀선의 위치, 형태 등은 현호색속의 분류체계를 반영하는 중요한 형질로 판단된다. 관찰결과 현호색절과 가는괴불주머니절의 밀선은 거(spur)의 1/3~2/3 정도 까지 신장되며 신장부는 매우 가늘지만 선단부에서는 다소 부푼 후 뾰족해지고 아래쪽으로 굽으며 분비조직이 위치하고 있는 부분은 녹색, 신장부는 횐색을 띠었다. 들현호색절에서는 거(spur)의 중간 정도에 위치한다. 기부는 두껍고 화색과 같은색을 띠지만 끝부분은 가늘고 굽지 않으며 흰색을 띤다. 자주괴불주머니절의 밀선은 거의 신장되지 않고 주걱형이며 노란색을 띠었다. 산괴불주머니절에서는 거(spur)의 3/4까지 신장되며 선단부는 뾰족하고 녹색을 띠며 아래로 굽는다. 밀선의 형태는 거(spur)의 형태와 관련이 있다. 거(spur)가 주머니처럼 부푸는 절에서 밀선분비조직의 뚜렷한 발달이 관찰되고 거(spur) 안에 분비된 화밀을 저장한다. 비록 현호색절과 산괴불주머니절이 서로 밀접한 계통을 갖지는 않지만 이들이 공유하는 밀선의 형태는 거(spur) 형태의 유사성에서 기인한 것으로 보인다. 한국산 현호색속 밀선의 형질진화 분석을 위하여 mesquite을 이용하여 ancestral reconstruction를 수행하였다. 밀선의 형질진화는 한국산 현호색속 5절의 계통진화를 반영하였다. 현호색속의 화부형질은 매우 복잡하고 다양한 방향으로 진화한 것으로 보이며 이를 이해하기 위해서는 다양한 화부형질의 종합적인 검토가 필요하다. 이번 연구에서 확인된 화부구조와 분비조직의 형질은 현호색속의 계통진화를 잘 반영하고 있었으며 향후 분비조직의 해부형질, 미세형질 등의 추가연구를 통하여 현호색속의 계통연구를 위한 새로운 분류학적 가치를 제공할 수 있을 것이다.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.617-625
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• 2022

This study attempted to compare and analyze metaverse platforms according to their functions. The five metaverse platform was selected and comparatively analyzed through in-depth interviews with experts. As a result of the research, first, Roblox allows you to create and customize your own avatar, provides studio functions for free, and allows you to enjoy private games with friends. Second, Zepeto can create an avatar with one selfie and provides a creative studio function. Third, in Fortnite, it is possible to create in-game characters, purchase and wear items provided in the game, and play games with friends in Creative Mode. Fourth, in Gather Town, networking with users in virtual space is possible, and your own avatar customization and desired virtual space template are provided. Finally, Facebook Horizon participates in the virtual world Horizon with its own avatar that you decorate yourself, and it can function as a world builder, and you can set up a billboard in virtual reality or a virtual store. The value of this study provided a theoretical basis that can be applied to the future industry through the characteristics of the metaverse platform.

• Composites Research
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• v.21 no.4
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• pp.15-21
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• 2008

Interfacial shear strength between epoxy and carbon fiber was analyzed utilizing a hemi-spherical microbond specimens adhered onto single carbon fiber. The hemi-spherical microbond specimen showed high regression coefficient and small standard deviation in the measurement of interfacial strength as compared with a droplet and an inverse hemi-spherical one. This seemed to be caused by the reduced meniscus effects and the reduced stress concentration In the region contacting with a pin-hole loading device. Finite element analysis showed that the stress distributions along the fiber/matrix interface in the hemi-spherical specimen had a stable shear stress distribution along the interface without any stress mode change. The experimental data was also different according to the kinds of loading device such as the microvise-tip and the pin-holed plate.

• Sleep Medicine and Psychophysiology
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• v.14 no.2
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• pp.92-98
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• 2007

Objectives: Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep-disordered breathing and often presents with comorbid depressive symptoms. In this study, we evaluated the relationship between depressive symptoms and sleep parameters as measured by nocturnal polysomnography (NPSG) and simultaneous wrist actigraphy. Methods: Two hundred sixty-four subjects with clinically suspected cases of OSAS underwent one-night polysomnography, while simultaneously wearing a wrist actigraphy device. They also completed two questionnaires；the Epworth Sleepiness Scale-Korean version (ESS-K) and the Beck Depression Inventory (BDI). Of the cases studied, 105 subjects were proven by NSPG to have OSAS without other sleep disorders. NPSG and wrist actigraphy data from the subjects were analyzed. Pearson correlation and paired t-test were used in order to evaluate the relationship between depressive symptoms and sleep-parameters. Results: Mean age of the subjects was $46.1{\pm}13.1$ years. Means of the ESS-K score and BDI scores were $10.9{\pm}4.7$ and $12.8{\pm}8.1$, respectively. NPSG sleep parameters significantly differed from those of wrist actigraphy. There was no correlation found between subjects' respiratory disturbance index (RDI) and BDI scores. When directly comparing sleep parameters between subjects who were more depressed versus subjects who were less depressed, both total sleep time and sleep efficiency were decreased in the more depressed. A correlation between RDI and ESS-K scores was also found in the more depressed group. Conclusions: Although our findings suggest that there is no relationship between RDI and depressive symptoms, there are other significant differences in the sleep parameters between subjects who are more depressed versus those without depression. We recommend that patients with depression should also be evaluated for clinical symptoms of OSAS.