• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.139-146
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• 2017

This study was conducted to develop a new drying technology in order to quickly and massively dry bamboo tubes without crack and check. The bamboo tubes with the diameter of 45 mm - 68 mm had been impregnated in the solution of PEG-1000, and then were dried under room temperature and high temperature, respectively. The cracks occurred on all control specimens while no cracks were found on PEG treated specimens during drying at room temperature due to effect of PEG restraining the circumferential shrinkage of bamboo tube. But the drying period of this method was too long (200 days) compared to 10 hours of kiln drying. During fast high temperature drying, cracks occurred on all control specimens, but no cracks were found on PEG treated specimens, which could be accounted for more solidified PEG due to higher drying temperature and faster drying rate, and the tension set formed on the surface of bamboo tube in the early stage of drying owning to high drying temperature and low relative humidity. Thus, it is advised that PEG treated bamboo tube should be fast dried at high temperature in order to not only prevent crack or check in short drying period but also increase the dimensional stability of the products made of bamboo tubes.

• 박물관보존과학
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• 제10권
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• pp.21-27
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• 2009

죽제조문필통은 직경 80mm정도의 통대 2개를 맞붙이고, 바닥에는"∞"모양의 가중나무 판재를 붙였다. 그리고 외부면에는 용과 구름, 사슴과 소나무 문양이 음·양각 기법으로 각각 정교하고 힘차게 조각되었다. 이 죽제조문필통은 일부가 파손, 결실 그리고 분해된 상태였지만 이번 보존수리를 통해 그 원형을 되찾게 되었다. 결실부에는 토분·호분·아교를 혼합하여 복원재료로 이용하였고, 원형을 되찾은 후 접합부분 안쪽에 얇은 비단 천을 부착하여 터짐을 방지하였다. 또한 복원된 표면은 옻칠을 이용해 고색처리를한것등 전통적인 재료와 수리기법을 응용한 가역적인 처리에 중점을 두었다.

• Journal of the Korean Wood Science and Technology
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• 제35권1호
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• pp.11-16
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• 2007

본 연구는 통죽의 송풍오븐 건조중 수증기댐 처리가 건조속도 및 할렬과 외주할 예방에 미치는 영향을 조사하였다. 생재에서 함수율 약 7~8%까지 건조되는데 소요되는 시간은 건조스케줄이 과격할수록 적었으며, 건조소요시간은 건조초기의 건조속도에 의해서 크게 좌우되는 것으로 나타났다. 건조중 횡단면적 수축율과 통피층의 두께수축율은 모두 비정상적일 정도로 매우 크게 나타났다. 무처리재의 경우 건조개시 직후 할렬과 외주할이 발생하였으며, 수증기댐 처리재에서는 약 67% 정도의 건조수율을 기대할 수 있었다. 수증기댐 처리재의 외주할은 건조조건 보다는 수증기댐 처리에 의한 횡단면을 통과하는 수분의 증발 차폐정도와 밀접한 관련이 있는 것으로 평가되었다.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.499-503
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• 2018

In this paper, cobalt embedded in nitrogen and sulfur co-doped carbon nanotubes (CoNSTs) were synthesized for oxygen reduction reaction (ORR) catalysts. The CoNSTs were prepared through a facile heat treatment method without any templates. Different amounts of the metal salt were employed to examine the physicochemical and electrochemical properties of the CoNSTs. The CoNSTs showed the bamboo-like tube morphology with the encased Co nanoparticles in the tubes. Through the x-ray photoelectron spectroscopy analysis, the catalysts exhibited different chemical states of the nitrogen and sulfur species. As a result, the CoNST performed high activity toward the ORR in an acidic condition with the onset potential of 0.863 V (vs. reversible hydrogen electrode). It was clearly demonstrated from the electrochemical characterizations that the quality of the nitrogen and sulfur species significantly influences the ORR activity rather than the total amount of the dopants.

• Journal of the Korean Wood Science and Technology
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• 제50권3호
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• pp.179-185
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• 2022

This study investigated the prospect of using peanut shells as an alternative and green sound-absorbing material. The sound-absorption coefficients were determined after filling impedance tubes of 30, 60, and 90 mm in height with peanut shells. The sound-absorption ability increased as the filling height increased, showing noise reduction coefficient (NRCs) of 0.23, 0.43, and 0.54 for the 30-, 60-, and 90-mm heights, respectively. In addition, for sounds greater than 2,000 Hz, the average sound-absorption coefficient of peanut shells in the 60- and 90-mm heights was 0.9. In summary, peanut shells were found to have good sound-absorption properties comparable to or better than those of bamboo, sisal, jute, and wool, and this research suggests that peanut shells may be useful as an environmentally friendly sound-absorbing material.

• 한국세라믹학회지
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• 제50권6호
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• pp.359-363
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• 2013

Silicon carbide and its composites are being considered as a nuclear fuel cladding material for LWR nuclear reactors because they have a low neutron absorption cross section, low hydrogen production under accident conditions, and high strength at high temperatures. The SiC composite cladding tube considered in this study consists of three layers, monolith CVD SiC - $SiC_f$/SiC composite -monolith CVD SiC. The volume fraction of SiC fiber and surface roughness of the composite layer affect mechanical and corrosion properties of the cladding tube. In this study, various types of SiC fiber preforms with tubular shapes were fabricated by a filament winding method using two types of Tyranno SA3 grade SiC fibers with 800 filaments/yarn and 1600 filaments/yarn. After chemical vapor infiltration of the SiC matrix, the surface roughness and fiber volume fraction were measured. As filament counts were changed from 800 to 1600, the surface roughness increased but the fiber volume fraction decreased. The $SiC_f$/SiC composite with a bamboo-like winding pattern has a smaller surface roughness and a higher fiber volume fraction than that with a zigzag winding pattern.