• Journal of Plant Biotechnology
• /
• 제32권4호
• /
• pp.301-306
• /
• 2005

Conditions for efficient organogenesis and plant regeneration from Dianthus gratianopol suspension cultured cells were established. Shoot-forming calli of glossy surface, pale green and knobby type were selected from leaf explant-derived calli and were suspension-subcultured every week in CP liquid medium with 1.0 mg/L 2,4-D and 0.5 mg/L BAP. Combinations of 1.0 mg/L 2,4-D and 0.5 mg/L BAP, and 1.5 mg/L 2,4-D and 0.5 mg/L BAP were effective for the induction of regenerative callus from the suspension cultured cell clusters. Multiple shoot primordia were initiated from the green spots of these regenerative callus and formed shoots on MS medium with 1.0 mg/L TDZ and 0.5 mg/L PAA. Shoot regeneration frequency (calli regenerating at least one shoot) was about 87%. For plant regeneration, proliferated shoots were excised and transferred to MS medium with 0.1 mg/L NAA for root initiation after 9 weeks of culture. The regenerants were potted in soil and formed the flowering buds and petals. Also, adventitious shoots were formed from the excised green shoot primordia of regenerative callus and these shoots proliferated successfully and regenerated to whole plants.

• Korean Journal of Metals and Materials
• /
• 제50권6호
• /
• pp.463-468
• /
• 2012

A 71.5 wt%Mg-23.5 wt%Ni-5 wt%$Fe_2O_3$ (Mg-23.5Ni-$5Fe_2O_3$) sample was prepared by a quite simple process, reactive mechanical grinding, and its hydriding and dehydriding properties were then investigated. The reactive mechanical grinding of Mg with Ni and $Fe_2O_3$ is considered to facilitate nucleation and shorten the diffusion distances of the hydrogen atoms. After the hydriding-dehydriding cycling, the Mg-23.5Ni-$5Fe_2O_3$ sample contained $Mg_2Ni$ phase. Expansion and contraction of the hydride-forming materials (Mg and $Mg_2Ni$) with the hydriding and dehydriding reactions are also considered to increase the hydriding and dehydriding rates of the mixture by forming defects and cracks leading to the fragmentation of the particles. The temperature dependence of the hydriding rate of the sample is discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2007년도 춘계학술대회 논문집
• /
• pp.302-305
• /
• 2007

The springback characteristics of AZ31B magnesium alloy sheet was investigated in OSU draw/bend test. Springback is the elastically-driven change of shape of a part after forming and it should be estimated and controlled to manufacture more precise products in sheet forming. The demands are increasing for magnesium alloy sheet press forming, but the study on its springback characteristics is insufficient. Strip draw/bend tests were conducted with various conditions - die radius, sheet thickness and controlled tensile force. The springback angles were measured from 'sidewall curl' of deformed shape. The tendency of springback angle was observed from the tests.

• Transactions of Materials Processing
• /
• 제17권7호
• /
• pp.466-472
• /
• 2008

In this paper, tension tests and formability tests are performed to construct a database related to mechanical properties and the formability of the AZ31B Mg alloy sheet. A forming test with a hemi-spherical punch is conducted at varying temperatures to establish a forming limit diagram. In order to verify the applicability of the analysis using the conventional flow hardening model, a finite element analysis is performed on the hemi-spherical punch forming process and the results are compared with experimental ones. The study investigates problems involving a computational analysis that does not consider flow softening of the magnesium alloy at elevated temperatures.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• 제34권3호
• /
• pp.32-37
• /
• 2002

The paper mill wastewater actually generating bulking was used to apply to the spot. Batch and continuous type pilots were used in this study. Optimal time after propagating generation of activated sludge in aeration basin by adding Hoc forming microorganism was 24 and 36hours while optimal time of activated sludge in original aeration basin was 60hours. Showing the difference of sedimentation velocity at 7th day after operating a pilot continuously, SV30 was decreased to 50% at 13th day. COD value in aeration basin with floe forming microorganism was 35mg/L while COD value in original aeration basin was 52mg/L. It was indicated that application of Hoc forming microorganism can control the bulking of paper mill wastewater by shortening of recovery time and improving of pollution removal efficiency.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.366-369
• /
• 2008

In this paper, tension tests and formability tests are performed to construct a database related to mechanical properties and the formability of the AZ31B Mg alloy sheet. A forming test with a hemi-spherical punch is conducted at varying temperatures to establish a forming limit diagram. In order to verify the applicability of the analysis using the conventional flow hardening model, a finite element analysis is performed on the hemi-spherical punch forming process and the results are compared with experimental ones. The study investigates problems involving a computational analysis that does not consider flow softening of the magnesium alloy at elevated temperatures.

• Journal of Korean Society of Environmental Engineers
• /
• 제31권7호
• /
• pp.557-564
• /
• 2009

The objective of this study is to efficiently recover phosphorus contained in sewage sludge by a struvite-forming method. The performances were evaluated under various operating conditions(elution with the kind of acid, Mg-compound and temperature) in order to reach the optimum conditions of struvite-forming. As a result, as an elution solution, the elution efficiency of $H_2SO_4$ was 2.65 times higher than that of HCl. Also, the precipitation efficiency of struvite was the highest (97.4%) in case of using $MgCl_2{\cdot}6H_2O$ as Mg-compounds at $25^{\circ}C$. However, the side reaction by Fe, Al and Zn appeared in process of phosphorus recovery. To solve some problems caused by side reacton, large quantities of co-precipitation materials produced by side reaction were removed by precipitating phosphorus compounds in pH 7. Consequently, the recovery efficiency of phosphorus by a struviteforming method was 82.99%, and purity of the recovered struvite product was high.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2007년도 추계학술대회 논문집
• /
• pp.91-92
• /
• 2007

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.395-395
• /
• 2008

• The Korean Journal of Ceramics
• /
• 제3권4호
• /
• pp.269-273
• /
• 1997

Chemical composition of cement powder influences the setting time and early compressive strength development. The setting time increases as the amounts of zinc oxide and magnesium oxide are increased. For one day compressive strength development, a cement powder with a composition 90% ZnO, 8% MgO and 2% silica resulted in the highest strength (greater than 1, 090 kg/$\textrm{cm}^2$). Cement-forming liquids also need to be buffered, with both aluminum and zinc ions, for a good consistency and a higher strength of the zinc phosphate cement. These liquids control the setting reactions.