• Fisheries and Aquatic Sciences
• /
• 제26권6호
• /
• pp.367-379
• /
• 2023

The rapid expansion of shrimp production requires a huge amount of protein sources from soybeans and wild-caught fishmeal; both are becoming a shortage. Meanwhile, catfish production and processing is a giant industry in Vietnam, which produce hundred thousand tonnes of protein- and lipid-rich by-products, annually. Using catfish by-products to gradually replace the traditional protein sources in shrimp aquaculture may bring triple benefits: 1) reducing pressure on wild fish exploitation for fishmeal, 2) reducing the environmental impacts of catfish by-products, and 3) increasing the value and sustainability of aquaculture production. In this study, we used catfish by-products to produce fish protein hydrolysate (FPH) and nano-hydroxyapatite (HA) as additives in feed for Pacific white shrimp (Litopenaeus vannamei). The supplement mixture of FPH and HA was added into the commercial diet (Charoen Pokphand Group [CP], 38% protein, and 6.5% lipid) to reach 38%, 38.5%, 40%, 43%, and 44% of the crude protein content. The survival and growth of shrimps were weekly assessed to day 55. The results showed that the shrimp growth was highest at 43% crude protein content in the feed as indicated by an increase of 124% and 112% in shrimp weight and length, respectively, compared to the commercial reference diet. No negative effects of adding the mixture of FPH and HA on the water quality were observed. Vibrio density was lower than 6.5 × 10³ CFU/mL, which is the lowest Vibrio density negatively affecting the shrimp growth and development. These findings indicate that the mixture of FPH and HA are promising additive components in feed for post-larval shrimp L. vannamei diets.

• 한국패류학회지
• /
• 제31권2호
• /
• pp.83-92
• /
• 2015

본 연구는 북방전복 육상 수조 내 고밀도 중간양성 방법을 모색하기 위해 부착면적 확대를 위해 다단식 shelter 설치와 수조 내 중층 이상의 가두리를 설치하여 성장을 비교하고 아울러 전복류 육상 양성방법인 'shallow race way' 국내 도입 가능성을 조사하였다. Shelter 실험구는 PE (polyethylene) 재질의 shelter ($63{\times}98cm$) 1층형 (the single layer shelter, SLS), 2층형 (the double layer shelter, DLS), 3층형 (the triple layer shleter, TLS) 과 육상 가두리 양성방식 (the single layer shelter and net cage culture, SLSNC), 그리고 'shallow race way' 방식을 polyvinyl chloride (PVC)로 제작하여 고랑수로양성 (culture of the ditch raceway tank, CDRT)과 편평한 수로양성 (culture of the floor raceway tank, CFRT) 방식을 설정하였으며, 실험구는 모두 2반복으로 실시되었다. 각 실험구별 SLS 기준 60%밀도로 수용한 실험 전복 (최초 수용 시 평균각장 $25.19{\pm}0.50mm$, 중량 $1.93{\pm}0.14g$), 성장에서 각장의 절대성장율 (absolute growth rate, ARG), 일간성장율 (daily growth rate, DGR) 및 순간성장율 (specific growth rate, SGR) 과 중량의 증중률 (weight gain, WG), 일간증중률 (daily weight gain, DWG) 에서 SLSNC 제외한 모든 실험구가 유의적인 차이가 없었다. 그리고 생존율에서는 CDRT와 CFRT가 유의적으로 낮았다 (P < 0.05). 따라서 shelter를 이용하여 부착면적을 확대한 고밀도 전복치패 육상 중간육성 사육 시 단층과 다단층에서 성장과 생존율에서 차이가 없으며, 호주 등에서 사용되는 shelter 없는 'shallow race way'의 얇은 수심사육은 국내 북방전복 육상 중간양성 방식으로 도입하기에 적합하지 않는 것으로 판단된다.

• 물과 미래
• /
• 제7권2호
• /
• pp.83-91
• /
• 1974

Fill Type Dam에 있어서 일반적으로 축조재료는 경제성을 감안하여 Dam Site 부근에서 구해야하므로 Core 용재료로서는 차수성의 문제만 해결된다면 마시토도 사용가능할 것이라는 전제하에 본문에서는 마사토를 단독 또는 혼합재료로서 각종시험을 실시하여 사용가능성 여부를 검토하고 기사용범위를 정함으로써 앞으로의 사용자들에게 편의를 제공코저 한다.

• Progress in Superconductivity
• /
• 제9권1호
• /
• pp.111-114
• /
• 2007

We have investigated the effect of different heat treatment processes on electrical and magnetic properties of Bi2212/Ag ROSAT wire. The ROSAT wire was fabricated by stacking and arranging 12 filaments Bi2212/Ag tapes in triple rotation symmetry in a Ag tube. ROSAT wires have been prepared using a partial melting method with changing $T_{max}$ and $T_a$ in oxygen atmosphere. The highest critical current density($J_c$) at 65 K under 0 T was $21,158\;A/cm^2$ for wire prepared $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$, respectively. SEM results indicated that the wire prepared at $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$ showed better directional phases than the other samples. However the result of magnetic susceptibility measurement indicates that the wire prepared $890\;^{\circ}C(T_{max})$ and $835\;^{\circ}C(T_a)$ had better superconducting phases than the other samples. It was revealed that heat treatment temperature was important factor for superconducting properties of the ROSAT wire.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.299-302
• /
• 2009

Oxygen ionic conductors of YSZ electrolyte in SOFC unit cell are applied to anode and cathode as well as electrolyte to have triple-phase-boundaries(TPB) of electrochemical reaction, and it is required to decrease the sintering temperature of anode-supported electrolyte by the nanoscale of YSZ powder.In this report, nanoscale YSZ powder was synthesized by the chemical co-precipitation method. The particle size, surface area and morphology of the powder were observed by SEM and BET. Thin film electrolyte of under 10㎛ was fabricated by tape casting using the synthesized YSZ powder, and ionic conductivity and gas permiability of electrolyte film were evaluated. Finally, the SOFC unit cell was fabricated using the anode-supported electrolyte prepared by a tape casting method and co-sintering. Electrochemical evauations of the SOFC unit cell, including measurements such as power density and impedance, were performed and analyzed.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.295-298
• /
• 2009

Oxygen ionic conductors of CeScSZ electrolyte in SOFC unit cell are applied to anode and cathode as well as electrolyte to have the triple-phase-boundaries of electrochemical reaction, and it is required to decrease the sintering temperature of anode-supported electrolyte by the nanoscale of CeScSZ electrolyte powder. In this report, nanoscale CeScSZ electrolyte powder was synthesized by chemical synthesis method. The particle size, surface area and morphology of the powder were observed by SEM and BET. Thin film electrolyte of under $10{\mu}m$ was fabricated by tape casting using the synthesized CeScSZ electrolyte powder, and ionic conductivity and gas permeability of electrolyte film were evaluated. Finally the SOFC unit cell was fabricated using the anode-supported electrolyte prepared by a tape casting method and co-sintering, in which the active layer, measuring $20{\mu}m$, was introduced in the anode layer to provide a more efficient reaction. Electrochemical evaluations of the SOFC unit cell, including measurements such as power density and impedance, were performed and analyzed.

• 천문학회보
• /
• 제42권1호
• /
• pp.58.4-59
• /
• 2017

Sanduleak's star is a suspected symbiotic binary located in the Large Magellanic Cloud. It is known that it has a giant jet with physical size ~ 14pc. Its spectrum shows two strong emission bands at $6825{\AA}$ and $7082{\AA}$, which are originated from Raman-scattering of O VI by neutral hydrogen atoms. We present the high-resolution spectrum of Sanudleak's star obtained with MIKE at the Magellan-Caly telescope to investigate the O VI emission region based on the profiles of the two Raman features. In this spectrum, it is noted that the Raman $6825{\AA}$ feature exhibits a single broad peak profile, which is in high contrast with a clear triple peak profile of the Raman $7082{\AA}$ feature. In our analysis we suggest that the O VI emission region consist of three main emission parts: an accretion disk, a bipolar outflow and an optically thick, compact component surrounding the white dwarf. By performing Monte Carlo simulation we constrain the representative column density of the H I scattering region N_HI ~1${\times}$10^23 cm^-2, which is in accordance with the observed flux ratio in the two Raman features F(6825)/F(7082) ~ 4.5.

• 한국산학기술학회논문지
• /
• 제6권1호
• /
• pp.54-57
• /
• 2005

반도체 소자 면적의 축소에 따라 중성자의 소프트 에러율은 집적회로 설계시 큰 문제점으로 대두되고 있다. 고전류 중성자 빔에 의한 가속 실험에서, 래치-업 현상은 소프트 에러 발생율의 정확한 예측을 방해하는 요소로 작용하고 있다. 본 연구는 SRAM 소자의 SER 가속 실험시 발생하는 래치-업에 대한 효과를 분석하였다. 2차원 소자 시뮬레이터를 이용한 시뮬레이션 환경하에서의 결과 깊은 p-well 구조의 기판이 이중 또는 삼중 well 구조에 비하여 양호한 래치-업 방지 효과를 나타내었다. 또한 접지에 대한 $V_{DD}$ 전력선까지의 거리를 최소화하는 것이 효과적인 설계 기법으로 평가되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.21-24
• /
• 2000

Ferroelectric YMnO$_3$ thin films are excellent dielectric materials for high integrated ferroelectric random access memory (FRAM) with metal-ferroelectric-silicon field effect transistor (MFSFET) structure. In this study, YMnO$_3$ thin films were etched with C1$_2$/Ar gas chemistries in inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$ thin films is 285 $\AA$/min under C1$_2$/Ar of 10/0, 600 W/-200 V and 15 mTorr. The selectivities of YMnO$_3$ over CeO$_2$ and $Y_2$O$_3$ are 2.85, 1.72, respectively. The results of x-ray photoelectron spectroscopy (XPS) reflect that Y is removed dominantly by chemical reaction between Y and Cl, while Mn is removed more effective by Ar ion bombardment than chemical reaction. The results of secondary ion mass spectrometer (SIMS) were equal to these of XPS. The etch profile of the etched YMnO$_3$ film is approximately 65$^{\circ}$and free of residues at the sidewall.

• International Journal of Aeronautical and Space Sciences
• /
• 제3권1호
• /
• pp.74-85
• /
• 2002

The numerical experiment has been conducted to investigate the unsteady shock wave reflecting phenomena. The cell-vertex finite-volume, Roe's upwind flux difference splitting method with unstructured grid is implemented to solve unsteady Euler equations. The $4^{th}$-order Runge-Kutta method is applied for time integration. A linear reconstruction of the flux vector using the least-square method is applied to obtain the $2^{nd}$-order accuracy for the spatial derivatives. For a better resolution of the shock wave and slipline, the dynamic grid adaptation technique is adopted. The new concept of grid adaptation technique, which is much simpler than that of conventional techniques, is introduced for the current study. Three error indicators (divergence and curl of velocity, and gradient of density) are used for the grid adaptation procedure. Considering the quality of the solution and the numerical efficiency, the grid adaptation procedure was updated up to $2^{nd}$ level at every 20 time steps. For the convenience of comparison with other experimental and analytical results, the case of interaction between the straight incoming shock wave and a sharp wedge is simulated for various flow conditions. The numerical results show good agreement with other experimental and analytical results, in the shock wave reflecting structure, slipline, and the trajectory of the triple points. Some critical cases show disagreement with the analytical results, but these cases also have been proven to show hysteresis phenomena.