• 수산해양기술연구
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• 제49권2호
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• pp.106-115
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• 2013

A series of fishing experiments were carried out in the western coastal waters of Korea from May, 2006 to September, 2007, using gill nets of different mesh sizes (m=101, 121.8, 152.5, 176.8, and 191 mm) to determine the mesh selectivity of gill net for swimming crab, Potunus trituberculatus. The catch species was composed of swimming crab (87%), Thomas's rapa whelk Rapana venosa (5%), arthritic neptune Neptunea cumingi (2%), Japanese swimming crab Charybdis japonica (2%), marbled sole Pleuronectes yokohamae (1%), pen shell Atrina pectinata, ocellate spot skate Okamejei kenojei, and so on. The carapace length (CL) of each swimming crab caught in the experimental nets was measured. Sponge crab (egg-bearing female crab) was appeared from the end of June to August in the coastal waters. The master selection curve was estimated by applying the extended Kitahara's method. The selection curve showed that the gill nets of larger mesh size allowed more crabs of small carapace size to escape. The optimum value (CL/m) was 0.645 and the CL/m was estimated to be 0.301, 0.354, 0.391, 0.422, and 0.450 when the retention probabilities were 0.1, 0.2, 0.3, 0.4 and 0.5, respectively.

• 수산해양기술연구
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• 제43권4호
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• pp.274-280
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• 2007

The mesh selectivity of gill net for Japanese sandfish (Arctoscopus japonicus) caught in the East Sea, Korea was described. The experiment was conducted with five different kinds of mesh size (39.4, 45.5, 51.5, 53.0, 57.6mm) between November and December 2006 in spawning season. The catch was mostly Japanese sandfish (93.3%) and some others (6.7%), and almost all of the female Japanese sandfish were larger than the fork length at 50% maturity (16.7cm). The selection curve for the female Japanese sandfish caught from the experiments was fitted by the Kitahara's method to a polynomial equation which was $s(R)={\exp}\{(0.2584R^3-5.3445R^2+32.269R-59.868)-0.6585\}$ where R＝l/m, and l and m are fork length and mesh size, respectively.

• 미생물학회지
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• 제6권4호
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• pp.113-121
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• 1968

This study has been aimed to determine the ecological factors with relationship to the Jongkok production in view of fermentation technology by means of some strains, Asp. kawachii, which is now preserved by the author and the following factors are included during the study; inorganic salts, nitrogen, sugar, water contents and temperature. The results, are as follows: (a) Sugar among other above-mentioned factors is increasingly affecting the number of the short type of conidiophore on culture medium and the conidiophore is increased by direct ratio until glucose concentration of 50%, at which concentration is mostly effective for the short type of conidiophore, while other factors did not affect on it. (b) Until glucose concentration of 50% sugar component of culture medium is favorable for the spore formation of Asp. kawachii by direct ratio. And peptone or asparagine on nitrogen medium, calcium-phosphate among other inorganic salts, wheat bran and rice branare also favorable, but other factors rientioned earlier show no relationship with the spore formation. Sugar, however, also related with the spore color clearness of crimson and light brown, and spore color is mostly clear at the point of glucose concentration until 50%. And asparagine on nitrogen medium, calcium phosphate among other inorganic salts, rice bran did all affect on the color clearness, while other factors did not concern with color clearness. (c) Water, sugar and temperature have related with the acid formation which is promoted, by direct ratio at the point of water-saturated condition and glucose concentration of 50%, while temperature at $25^{\circ}C$favorably affected on the acid formation which is increased by inverse ratio at the temperature$25^{\circ}C$ to $45^{\circ}C$ And pH did not relate with the acid formation. (d) Cylindrical plate method devised by the author is mostly favorable for the preservation and isolation of culture, compared with the traditional slant medium method.

• 대한수학회보
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• 제33권3호
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• pp.455-463
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• 1996

In [3] and [4], Kitahara, Pak and the author obtained the conformally invariant tensor $B_0$, which is an algebraic Hermitian analogue of the Weyl conformal curvature tensor W in the Riemannian geometry, by the decomposition of the curvature tensor H of the Hermitian connection and the notion of semi-curvature-like tensors of Tanno (see[7]). In [5], the author defined a conformally invariant tensor $B_0$ on a Hermitian manifold as a modification of $B_0$. Moreover he introduced the notion of local conformal Hermitian-flatness of Hermitian manifolds and proved that the vanishing of this tensor $B_0$ together with some condition for the scalar curvatures is a necessary and sufficient condition for a Hermitian manifold to be locally conformally Hermitian-flat.

• 한국표면공학회지
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• 제53권4호
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• pp.144-152
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• 2020

In the manufacturing process of joining of aluminum alloy and polymer, the strength of the metal-polymer joining is greatly influenced by the nanostructure of the oxide film. In this study, we investigated the dependence of joining strength on the thickness, structure, pore formation and surface roughness of the formed film. After the two-step anodization process, the surface oxide layer became thinner and rougher resulting in higher joining strength with the polymer. More specifically, after the two-step anodization, the surface roughness, Ra increased from 2.3 to 3.2 ㎛ with pore of three-dimensional (3D) nanostructure, and the thickness of the oxide film was thinned from 350 to 250 nm. Accordingly, the joining strength of the aluminum alloy with polymer increased from 23 to 30 MPa.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.182-186
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• 2000

The porous woven hose is recently considered as an effective element of automotive intake systems. In order to predict the acoustic performance of an intake system with a porous woven hose, the information on the acoustic wall impedance is required. In this article, a measurement technique that is valid over the low frequency range and without mean flow condition is presented. The measurement is performed in a cylindrical chamber with a concentric layout of the sample and the resistance is estimated from measured reactance and transmission loss data. It is observed that the measured transmission loss for a porous woven hose with an arbitrary length agrees well with the predicted one that uses the estimated impedance for a small sample length.

• 수산해양기술연구
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• 제36권2호
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• pp.89-95
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• 2000

서대 3중자망의 망목 선택성을 규명하기 위하여 각각 3가지 종류의 망목(70.5mm, 86.6mm, 101mm)으로 구성 된 자망 및 3중자망을 사용하여 1999년 5월부터 8월까지 전남 여수시 돌산도 연안에서 총 30회의 실험조업을 하고, 그 결과를 분석하였다. 망목 선택성 곡선은 개서대를 대상으로 Kitahara 방법으로 작성되었다. 본 연구에 대한 결과를 요약하면 다음과 같다. 1. 현용어구 규격인 3중자망(내망 망목 70.5mm망)의 어획비율은 39.0%로, 자망 15.8%에 비해서 약 2.5배 높았다. 2. 3중자망의 선택률이 1이 되는 최적 l/m값은 3.51로 자망 3.38에 비해서 약 0.13 높게 나타났다. 3. 3중자망의 낮은 체장계급에서의 선택성은 자망과 비슷하였으나, 높은 체장계급에서의 선택성은 자망에 비해서 떨어졌다. 이 때 3중자 망의 50% 선택 구간은 1.33으로 자망 0.83에 비해 1.5배 넓게 나타났다. 이상의 결과에서 볼 때, 서대의 경우 3중자망은 자망에 비해 어획성능이 우수하고, 망목 크기를 조절함으로서 대상 어종의 어획 체장을 제어할 수 있음을 알 수 있었다.

• 수산해양기술연구
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• 제41권1호
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• pp.27-34
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• 2005

붕장어에 대한 스프링형 그물통발의 망목선택성 및 적정망목을 추정하기 위한 시험조업은 경남 거제시 능포 인근해역에서 2002년 9월25일${\sim}$9월27일에 실시되었다. 시험어구는 현용어구인 15mm, 20mm 및 시험을 위해 제작한 25mm, 30mm 그리고 수산자원보호령에서 규정하고 있는 35mm와 대조어구로써 통수공 6.7mm의 플라스틱 통발을 각각 50개씩 제작하여 사용하였다. 망목선택성은 Kitahara(1968)와 Fujimori(1996)의 방법을 사용하여 분석하였고, 적정망목은 어체 동주와 체장과의 관계 그리고 망목선택성 Master Curve를 사용하여 추정하였다. 그 결과를 요약하면 다음과 같다. 1. 시험조업 결과 총어획미수는 835미로, 붕장어 537미(64.4%), 게류 225미(26.9%), 기타 73미(8.7%)였다. 2. 망목선택성 곡선의 Master Curve에서 최대 전장/망목(max. 1/m)의 값은 23.9로 추정되었다. 3. 붕장어 스프링 통발의 적정망목은 34.0mm로 추정되었다.

• 수산해양기술연구
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• 제38권2호
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• pp.91-100
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• 2002

삼중자망의 망목 선택성 및 적정망목을 추정하기 위하여 강원도 주문진 해역에서 2000년 8월 10~13일, 11월 9~13일 (18회), 부산 수영만에서 2001년 6월 1일~27일(21회), 시험조업을 행하였다. 또한 주문진 해역에서는 60, 75, 90 105, 135, 150, 180mm의 7가지의 삼중자망으로 조업하였고, 수영만에서는 60, 75, 90mm의 삼중자망과 홑자망으로 비교실험을 행하였다. 망목 선택성 곡선의 분석은 전체 어획량의 약 60%를 차지하는 물가자미(Eopsetta grigorjewi) 를 대상으로 하였으며, Master curve의 다항식이 포함된 Kitahara(1968)방법을 사용하여 작성하였다. 그 결과를 요약하면 다음과 같다. 1. 총 어획미수는 삼중자망이 2,331미였고, 홑자망이 1,433미였으며, 가자미류가 59.8%~60%였다. 2. 최적 l/m값은 삼중자망이 2.56이었으며, 흩자망이 2.47로 삼중자망이 약 0.1 정도 크게 나타났다. 3. 50% 선택구간은 삼중자망이 1.88~3.36(1.48)로 나타났으며, 홑자망은 2.00~3.02(1.02)로 삼중자망이 약 1.5배 정도 넓게 나타났다. 4. 가자미의 최소성숙체장 265mm에 대한 적정망목은 삼중자망이 약 141mm, 홑자망이 약 132mm로 삼중자망이 약 10mm 정도 크게 나타났다. 5. 적정망목을 사용했을 경우 50% 선택 체장범위는 삼중자망이 265mm~474mm, 흩자망이 265mm~398mm로 삼중자망의 체장범위가 76mm 정도 넓은 것으로 나타났다.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.155-158
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• 2000

NMR study has been used for measuring precise quantity of the amorphous phase in the $Si_3N_4$powder. Care must be taken to allow the $^{29}$Si nuclear spin system to fully relax between pulses in order to make the signals proportional to the number of nuclei in each phase. $^{29}$Si MAS spectrum was decomposed into the three spectra of $\alpha$-, $\beta$-, and amorphous $Si_3N_4$assuming pseudo-Voigt function. Moreover, the Rietveld analysis of the powder X-ray diffraction data was performed to measure quantity of crystalline phases as $\alpha/\beta$ ratio.