• 한국산림과학회지
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• 제51권1호
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• pp.41-50
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• 1981

본연구(本硏究)의 목적(目的)은 현재(現在) 증량제(增量剤)로 사용(使用)하고 있는 도인소맥분(導人小麥粉)을 국내(国內)에서 값싸게 생산(生産)할 수 있는 다른 증량제(增量剤)로 대체(代替)키 위한 가능성(可能性)을 규명하는데 있다. 증량재료(増量材料)는 옥촉서간(玉蜀黍幹), 송수피(松樹皮), 소맥(小麥), 리기다송엽(松葉), 잣나무엽(葉) 및 목분말(木粉末)을 택(択)해서 $103{\pm}2^{\circ}C$에서 24시간(時間)동안 전건(全乾)시킨 다음 60~100mesh로 분쇄(粉碎)하였다. 증량방법(増量方法)에 있어서 요소수지(尿素樹脂)는 10, 20, 30, 50%로 증량(増量)하였으며 수용성석탄산수지(水溶性石炭酸樹脂)는 5, 10, 15, 20%로 증량(増量)하였다. 본연구(本硏究)에서 얻은 결론(結論)은 다음과 같이 요약(要約)할 수 있다. 1. 요소수지(尿素樹脂)에 있어서 상태접착력(常態接着力)은 소맥분(小麥粉)이 가장 양호(良好)하였다. 2. 요소수지(尿素樹脂)에 있어서 내수접착력(耐水接着力)은 10%와 20%증량(増量)의 경우 소맥분(小麥粉)보다 목분(木粉)이 더 양호(良好)하였으나 이들 사이의 유의적(有意的)인 차이(差異)는 없었다. 3. 석탄산수지(石炭酸樹脂)의 상태접착력(常態接着力)에 있어서 5%증량((増量)의 경우 잣나무엽분(葉粉)이 가장 양호(良好)하였으나 10, 15, 20% 증량((増量)의 경우는 소맥분(小麥粉)이 가장 양호(良好)하였다. 4. 석탄산수지(石炭酸樹脂)의 내수접착력(耐水接着力)에 있어서는 소맥분(小麥粉)이 가장 양호(良好)하였다. 5. 석탄산수지(石炭酸樹脂)의 상태(常態) 및 내수접착력(耐水接着力)에 있어서 15와 20%증량((増量)의 경우 옥촉서간(玉蜀黍幹)이 소맥분(小麥粉) 다음으로 양호(良好)한 결과(結果)를 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제10권3호
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• pp.118-131
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• 1982

1. 이 연구(硏究)는 Yale대학교(大學校) 임과대학목재이학교실(林料大學木材利學敎室)에서 최근(最近) 새로히 쓰기 시작(始作)한 phenolic resin의 일종(一種)과 soy-bean glue 1auxein 10-B에 대(對)하여 assembly time의 변동(變動)이 제작(製作)된 합판(合板) shear strength에 어떠한 영향을 주는가를 알고 또한 그의 비교적(比較的) 적당(適當)한 실질적(實質的)인 assembly time의 범위를 결정(決定)하기 위하여 실시(實施)된 것이다. 2. 이 연구(硏究)에서 쓴 단판은 동실험실(同實驗室)에 실험용재료(實驗用材料)로 비치(備置)된 1/22in. 너도 밤나무(beech) 단판을 사용(使用)하였으며 수지는 phenolic resin U.S.P. low temperature liguid resorcinol type 와 Lauxein No. 10-B cold press water - resistant soygule 등으로 실험용(實驗用) sample을 구입(購入)하여 사용(使用)하였다. 3. 실험용(實驗用) ply-wood는 삼합식(三合式)으로 실험(實驗)을 하게 된 assembly time의 variation은 일분(一分)에서 시작(始作)하여 5, 10. 15, 25, 35, 50, 70분(分)등으로 8개(個)의 variation이 있게 하고 assembly 법(法)으로는 open assembly와 closed assembly의 2법(法)으로 하였으며 제작(製作)된 ply-wood의 성질비교(性質比較)는 dry test와 wet test의 shear strength test를 통(通)하여 나타나는 shear strength와 목파율을 가지고 하였다. 4. assembly time의 variation에 따른 합판의 shear strength와 목파율은 Table 1. 2. 3. 4에 표시(表示)된 바와 같은 결과(結果)를 보였으며 phenolic resin을 갖이고 closed assembly 법(法)으로 제작(製作)된 합판의 wet test를 제외하고는 모두 assembly time이 증가(增加)됨에 따라 shear strength와 목파율은 감소(減少)되여 가는 경향(傾向)을 보이고 있다. 그리고 실질적(實質的)으로 유효(有效)한 assembly time의 범위는 다음 표(表)(8)과 같다. 5. 이 실험(實驗)을 하는 동안 친절(親切)한 충고(忠告)와 지도편달(指導鞭達)를 애끼지 않고 도와주신 Yale 대학교(大學校) 목재이용학교수(木材利用學敎授) Dr. F.F.Wangaard씨(氏)와 Prof. Hess a. 그리고 실험실(實驗室) 담임자(擔任者)인 Mr. Clanch씨(氏)에게 충심(衷心)으로 사의(謝意)를 표시(表示)한다.

• 펄프종이기술
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• 제46권4호
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• pp.62-68
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• 2014

The application of conifer leave to the papermaking process as a functional organic filler was investigated in this study. The powder of the conifer leave after hot water extraction for the functional extract, such as phytoncide, was applied to OCC stock. The comparison between the commercial wood flour and the conifer leave powder as organic filler for OCC paper were conducted with various wet pressing conditions. The amount of the water removal by the wet pressing process and the bulk of handsheet were increased by the addition of the wood flour and the conifer leave powder, although the tensile strength was decreased. At the higher pressure condition of the wet pressing, the wet pressing efficiency was greatly increased by the wood flour and the conifer leave powder. There was a little difference in the performance of the wood flour and the conifer leave powder as an organic filler. Those results showed the conifer leave powder could be an alternative resource to the wood powder for papermaking organic filler.

• 수산해양기술연구
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• 제54권2호
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• pp.97-106
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• 2018

The objective of this study was to estimate physical properties and fishing performances of net twine with improved PBS copolymer resin (Bio-new), the existing PBS/PBAT blending resin (Bio-old) and commercial Nylon (Nylon). The tensile strength of Bio-new monofilament was equal to Bio-old and the elongation of Bio-new was about 6 % higher than that of Bio-old in wet condition. The physical properties tests were carried out to estimate breaking load and stiffness in dry and wet conditions, respectively. In the results, the breaking load of Nylon netting was the highest whereas the elongation of Bio-new was 1.4 times higher than that of Nylon netting in wet condition. The breaking load of Bio-old netting was about 9.2 % higher than that of Bio-new netting. However, the elongation of the Bio-new netting was about 3% higher than that of Bio-old. The stiffness of the Bio-new compared to Bio-old was improved about 34 % in dry condition and about 32 % in wet condition. The filed experiments of the fishing performance were conducted with three kinds of drift nets with different netting materials in the coastal sea of Jeju. The each experimental drift net made of different materials showed the similar fishing performance. Bio-old drift net yielded less catches of small sized yellow croaker than other drift nets. The netting materials affected the fishing performance and length distribution of catches in the drift nets.

• 한국건설순환자원학회논문집
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• 제1권3호
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• pp.211-218
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• 2013

해양환경 조건 중 건습반복환경인 간만대는 구조물내 철근부식이 가장 빨리 일어나는 것으로 알려져 있다. 때문에 부식촉진시험 방법 중 간만대 환경을 재현한 시험방법이 가장 활발하게 진행되어왔다. 그러나 많은 연구들이 부식임계농도 추정이나 염화물침투해석에 집중되어 있는 상황이다. 본 논문에서는 건습반복조건의 환경을 재현하여 구조물내 철근부식촉진시험과 염화물 침투해석을 실시하였다. 배합에 사용된 재료의 종류를 변수로 시험을 실시하였으며, 철근부식모니터링 방법으로 갈바닉 전위측정법과 반전지전위법을 사용하여 철근부식의 유무를 판단하였다. 부식촉진시험결과 각 배합별로 부식기간이 차이가 났으며, 순서는 OPC > FA > BS > 고강도 순으로 나타났다. 부식촉진시험과 동일한 조건으로 FEM 내구성 해석 프로그램인 DuCOM, RCPT 시험을 실시하여 실험결과 값에 대한 타당성을 입증하였다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2009년도 춘계학술발표회 논문집
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• pp.23-28
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• 2009

The purpose of this study was to improve not only wet-end performances but also paper characteristics by the modification of various factors like molecular design and ionic characteristics of polyacrylamides First of all physical characteristics were observed after modify molecular design of the cationic polyacrylamides to linear, branched and cross-linked. In addition it was found analysis method to confirm branch degree of cationic polyacrylamides to combine ionic titration characteristics and spectroscopic behavior, After application of these structure modified polyacrylamides to the multiple retention systems with inorganic microparticles, it was found adjusting of branch degree of polyacrylamides was very important to optimize wet-end improvement. Second, After polymerization of amphoteric polyacrylamide to have both of cationic and anionic functional group in the polymer, we observed not only physical characteristics but also wet-end improvement to apply recycled pulp and found that the improvement of solution stability to prevent hydrolysis and increase of ash retention dramatically to compare traditional cationic polyacrylamide retention aid, Finally, After polymerization of anionic polyacrylamide, we observed not only wet-end improvement but also paper characteristics to apply preflocculation of PCC and it was found the improvements of flocculation efficiency, retention, ash retention, optical properties of the paper and bursting strength to compare traditional preflocculant of cationic polyacrylamide.

• 터널과지하공간
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• 제2권2호
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• pp.224-236
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• 1992

It is very important to determine the thermo-mechanical characteristics of the rock mass surrounding the repository of radioctive waste and the LPG storage cavern. In this study, Hwasoon-Shist. Dado-Tuff adn Chunan-Tonalite were the selected rock types. Temperature dependence of the mechanical properteis such as uniaxial compressive strength, tensile strength, Young's modulus was investigated by measuring the behaviour of these properties due to the variation of temperature. Also, the characteristics of strength and deformation of these rocks were examined through high-temperature triaxial compression tests with varing temperatures and confining pressures. Important results obtained are as follows: In high temperature tests, the uniaxial compressive strength and Yong's modulus of Tonalite showed a sligth increase at a temperature up to 300$^{\circ}C$ and a sharp decrease beyond 300$^{\circ}C$, and the tensile strength showed a linear decrease with increasing heating-temperature. In high-temperature triaxial compression test, both the failure stress and Young's modulus of Tonalite increased with the increase of confining pressure at constant heating-temperature, and the failure stress decreased at 100$^{\circ}C$ but increased at 200$^{\circ}C$ under a constant confining pressure. In low temperature tests, the uniaxial compressive and tensile strengths and Young's modulus of these rocks increased as the cooling-temperature is reduced. Also, the uniaxial compressive and tensile strengths of wet rock specimens are less than those of dry rock specimens.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.49-52
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• 2006

Extrusion concrete panel is made by extrusion of high viscosity paste. The high viscosity paste is made by mix of cement, silica, reinforced fiber and thickening agent in the dry mixer and wet mixer subsequently, extrusion in the extruder, and curing in the normal steam curer and high pressure steam curer subsequently. To increase a flexural strength of the panel, it is used inorganic fiber as like asbestos. But it was known that the asbestos was harmful to human being lately, in the domestic area it is restricted usage in the construction materials. So, it is demanded the alternative material for asbestos in the extrusion concrete panel. This study is to investigate that the sepiolite is possible to be the alternative of asbestos. The 3 types of sepiolite is applied to the extrusion concrete panel. To investigate the properties of the panel with sepiolite, it is compared the control with asbestos in the flexural strength, the specific density and the spot compressive strength. From the test results, it was found that the panel with sepiolite B is higher than the control with asbestos in the flexural strength and in the density.

• 대한치과보철학회지
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• 제40권6호
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• pp.572-576
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• 2002

This investigation was designed to estimate the biaxial flexure strength and fracture toughness of lithium disilicate glass-ceramics of IPS Empress 2 system pressed with as-received ingots and their sprue buttons. Two groups of the lithium disilicate glass-ceramics were prepared as follows: group 1 is ingot-pressed group; group 2 is sprue button-pressed group. A ball-on-three-ball test was used to determine biaxial flexure strength (BFS) of disks in wet environment. Scanning electron microscopy(SEM) analysis was conducted to observe the microstructure of the ceramics. Unpaired t-test showed that there were no differences in the mean biaxial Hem strength (BFS) and KIC values between group 1 and 2 (p > 0.05). Two groups showed similar values in the KIC and the strength at 5% failure probability. The SEM micrographs of the IPS Empress 2 glass-ceramic showed a closely packed, multi-directionally interlocking pattern of numerous lithium disilicate crystals protruding from the glass matrix. The lithium orthophosphate crystals could not be observed on the fracture surface etched. There was no a marked difference of the microstructure between group 1 and 2. Although there were no tests including color stability, casting accuracy, etc., the results of this study implied that we could reuse the sprue button of the pressed lithium disilicate glass-ceramic of IPS Empress 2 system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.263-263
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• 2008

This paper describes the electrical strength of a toughened glass stem insulators employed for electric railways. The broken glass stem insulators for comparison were taken at site. According to the international standards, electrical strength tests with 60[Hz] voltage and with impulse voltage were carried out to them under dry and wet condition and the results were corrected by considering the temperature and humidity factors. Based on the experimental results, the electrical strength of broken glass stem insulators was compared with those of sound ones and surface flashover characteristics were also discussed. As a result, it was confirmed that the electrical discharge is formed by bridging each end of the insulator shell. The experimental results are expected to be utilized as data for electrically identifying the failure causes of glass insulators.