nanoparticle was synthesized by the flame method, which was controlled by varying the ratio and flow rate of gas mixtures consisting of oxygen (oxidizer), methane (fuel) and nitrogen (carrier gas). The crystalline phases of nanoparticle depended strongly on the temperature distribution in the flame, whereas the morphology was not sensitive. We proved that the anatase phase formed without the phase transformation in the flame and the rutile phase generated through several phase transformations.
For the adsorption of ammonia, activated carbon fibers (ACFs) were subjected to sulfuric acid treatment in order to modify the surface functional groups. The surface acid and base value of ACFs were measured using titration and FT-IR spectrometry. SEM was used to investigate the surface morphology. Acid treatments by H3PO4, H2SO4, and HNO3 were performed to increase the adsorption capacity of NH3. As a result, Cellulose-based ACF has high adsorption capacity for ammonia. The ammonia removal efficiency of ACF was the maximum which was treated by 15 wt% sulfuric acid at 100℃ for 60 min. The average pore diameter little increased from 19a to 20.8a and the specific surface area of ACF considerably decreased and acid values increased by 15 wt% sulfuric acid treatment. Ammonia reacted with sulfonyl radicals. After adsorption of ammonia, white material was grown on the surface of ACF through the adsorption of ammonia and it was determined to ammonium sulfate.
The collision of two particles in the accretion disk may lead to be a mechanism of heat generation. By using hydrodynamic equations, the mean free path, the collision frequency and the deflection angle due to the collision of the particles are derived as a function of the mass accretion rate. The mean free path seems to be a smaller fraction compared to the dimension parameter of the system. The radiative flux in the disk is obtained under the influence of the collision of the particles.
쇠파리의 실내 대량사육을 위한 시험에서 산란전기간을 단축 시킴으로써 사충율을 저하시키며 누대사육에 의한 위소현상을 조사하기 위해 각 세대별 용중량의 차이를 조사 하였으며 쇠파리는 성충기 이외에는 자웅구별이 불가능하므로 용중량에 의한 성구별을 시도한 결과는 다음과 같다. 1) 유충 media로부터 용을 분리할 때 사용하는 물을 약 로 가온하여 용을 채취한 결과 산란전기간이 8일로 단축되었다. 2) 누대사육에 의한 세대별 위소현상 조사에서 명세대별 용중량차이에는 유의성이 없었으며 사육온도에 따라서 많은 차이를 보였다. 3) 용중량의 차이에 의한 성구별은 약 의 웅충구별이 가능하였다
1) 쇠파리의 누대 실내사육을 위한 온도는 약 가 좋으며, 이때 유충기간은 약 6.8일, 용기간은 5.3일, 산란전기간은 10.4일, 성충의 수명은 약 30일이었다. 2) 인공사육에 있어서 용화율은 우화율은 였으며 성비는 1 : 1이었다. 3) 용의 체중량은 약 14.5mg이었으며, Wheat bran medium 보다 Standard medium이 사육성적이 좋았다. 4) medium 125gr에 대한 난의 접종수는 약 310개가 가장 적합하였다. 5) rectangular cage를 사용할 경우, 성충의 resting place는 가 적합할 것으로 본다.
The present study examined the possibility of long term storage, by cryopreservation in liquid nitrogen, of the sperm of Filefish (Thamnaconus septentrionalis), and the changes in motility, survival rate and ultrastructure of the sperm after freezing and thawing. The sperm was collected by stripping and stored on ice until experiments. For selection of the immobilizing solution, diluted artificial seawater (ASW) of 20, 30 and 40% were tested. The sperm motility was significantly inhibited in 30% ASW, and restored entirely after 100% ASW was added again. Two cryoprotectants, dimethyl sulfoxide (SO) and glycerol, were added to 30% ASW to formulate the extenders at the concentrations between 5 to 20% by volume for freezing. The sperm was diluted at the ratio of 1 :6 with the extenders, inserted into 0.5ml plastic straws and frozen at a freezing rate of /min to after equilibration for 10 min at room temperature, followed by plunging into liquid nitrogen. The straws were thawed in a water bath for 15 sec. The highest post-thawed sperm motility and survival rate were obtained with 5% glycerol Afterward, the effect of different freezing rates was examined using 5% glycerol as a cryoprotectant, and the rate of /min to showed the best result Some ultrastructural changes of sperm, such as the detachment of plasmatic and nuclear membranes, destruction of mitochondria, were observed after cryopreservation. Morphological normality of the sperm in 5% glycerol frozen at the ratio of 1/min to was better than that of others.
The present study examined the possibility of cryopreservation of the D-shaped and umbo larvae of arkshell (Scapharca broughtonii), in terms of the survival rates after freezing and thawing. D-shaped and umbo larvae of arkshells were obtained from a shellfish farming on Yosu city. The average shell lengths were m and , respectively. Five cryoprotectants (CPAs), dimethyl sulfoxide (DMSO), glycerol, ethylene glycol (EG), propylene glycol (PG), and methanol, were tested at the concentrations of 1.5, 2.0 and 2.5 M. After larvae suspended in CPAs, cryoprotectants were loaded in 0.5 ml straws at a larval density of 50-100 larvae per straw, and epuilibrated for 10 and 20 minute at room temperature (), repectively. Straws were cooled at a rate of /min from to , held for 5 min at , and then cooled at /min to and equilibrated for 5 min followed by plunging in liquid nitrogen. After storage in liquid nitrogen for 1 day, straws were thawed in a water. As soon as straws were observed to melt, larvae were diluted with an equal volume of ASW and then washed twice with a large volume of ASW at an interval of 2 min to unload the CPAs. The results showed that after equilibration for 10 and 20 minute at room temperature, no larvae survived using methanol as CPAs, and it was observed that larval shells all open slightly, and larval flesh broke down and slopped over the shells. The highest survival rates (D-shaped larvae: 77.6%, umbo larvae: 59.3%) were obtained with 2M DMSO, and 1.5M glycerol yielded survival rates of 53.8% for D-shaped larvae and 37.5% for umbo larvae. The surviving D-shaped larvae showed active rotary motion and perfect membrane integrity and cytoplasmic normality, and the vigorous movement of veliger cilia was observed inside the closed shells. The breakdown of tissue occurred in the abnormal larvae, and the isolated cell often run out of shells.