• Journal of Plant Biology
• /
• v.12 no.3
• /
• pp.26-34
• /
• 1969

Through immersing barley seeds (variety; Suwon No. 6) into different dilution of carrier-free P-32 original solution (Total activity; 90mc, To; 3/21) for 24 hours at room temperature, four groups of seeds (each group consists of 200 seeds) having activity levels of 1.6$\times$10-3$\mu$c 32P/grain, 2.3$\times$10-1$\mu$c 32P/grain 6.9$\times$100$\mu$c 32P/grain and 2.5$\times$101$\mu$c 32P/grain respectively, were obtained. To investigate the effects of various activity levels of P-32 absorbed upon the test plants, the seeds were germinated, transplant into the pots, and the growth was observed for three months after germination. After harvest, the inorganic contents in the leaves and the stems were also analyzed. The results: 1) Until four days after the beginning of germination, the rate of germination was found the lowest at the strongest activity level of 2.5$\times$101$\mu$c/grain. At the other P-32 levels treated, it showed generally higher than the control. 2) Before transplanting the seedlings of both 1.6$\times$103$\mu$c/grain and 2.3$\times$10-1uc/grain levels showed more vigorous growth than the control, whereas at the 6.9$\times$100 uc/grain level a retarded growth was conspicuous and all of plants belonging to the highest activity level of 2.5$\times$101$\mu$c/grain were withered owing apparently to the radiation damage. 3) This trend of growth promotion was continnually observed at the low activity levels even after transplanting the seeldings to the pots. As for the plants belonging to 6.9$\times$100$\mu$c/grain level, a clear sign of gradual recovery from the damage afflicted at the earlier stage was observable, and as a result the plants showed more growth than those of control two months after transplanting. 4) The number of stems diverged was found somewhat small in the blocks treated with P-32, compared with that of control until two months after germination. At the later stage of growth there seemed no significant difference among the themselves. 5) The dry weight of leaves and stems was proved that the lower the activity, the mroe it was produced. The relative increase of dry matter in each treatment compared with the control was 2% at 6.9$\times$105$\mu$c/grain level, 9% at 2.3$\times$10-1$\mu$c/grain and 35% at 1.6$\times$10-3$\mu$c/grain respectively. 6) The inorganic contents of the leaves and stems harvested were proved that: (1) Nitrogen was highest at the lowest activity level of 2.3$\times$10-1$\mu$c/grian. (2) Phosphorus showed generally higher contents in the treated blocks than in control, with the peak being at 2.3$\times$10-1$\mu$c/grain. (2) Phosphorus showed generally higher contents in the treated blocks than in contro, with the peak being at 2.3$\times$10-1$\mu$c/grain level in the leaves and at 6.9$\times$100$\mu$c/grain in the stems. (3) These was no significant difference in potassium contents in the leaves between treatment and control, whereas in the stem the treated blocks were higher than control roughly in propotion to the activity level. (4) Calcium in the lesves was richer in treated blocks than control while in the stem no difference was seen. (5) Magnesium contents both in leaves and in stems there was no difference among treatments.

• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.83-86
• /
• 1989

Electrical conductivity, I - V and DLTS have been measured on polycrystalline samples of $\alpha-Fe_{2}O_{3}$ containing small deviation from stoichiometry and small amounts of added titanium. DLTS (Deep Level Transient Spectroscopy) in the current transient mode has been applied to the measurement of the trap density at the grain boundary. Titanium enters the $\alpha-Fe_{2}O_{3}$ lattice substitutionally as $Ti^{4+}$, thus producing an $Fe^{2+}$ and maintaining the average charge per cation at three. The $Fe^{2+}$acts as a donor center with respect to the surrounding $Fe^{3+}$ions.

• Journal of Powder Materials
• /
• v.16 no.6
• /
• pp.403-409
• /
• 2009

Plasma spray forming is recently explored as a near-net-shape fabrication route for ultra-high temperature metals and ceramics. In this study, monolithic tungsten has been produced using an atmospheric plasma spray forming and subsequent high temperature sintering. The spray-formed tungsten preform from different processing parameters has been evaluated in terms of metallurgical aspects, such as density, oxygen content and hardness. A well-defined lamellae structure was formed in the as-sprayed deposit by spreading of completely molten droplets, with incorporating small amounts of unmelted/partially-melted particles. Plasma sprayed tungsten deposit had 84-87% theoretical density and 0.2-0.3 wt.% oxygen content. Subsequent sintering at 2500$^{\circ}C$ promoted the formation of equiaxed grain structure and the production of dense preform up to 98% theoretical density.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.315-318
• /
• 2004

We developed a vapor induced crystallization (VIC) process for the first time to obtain high quality polycrystalline Si films by sublimating the mixture of $AlCl_3$ and $NiCl_2$. The VIC process enhanced the crystallization of amorphous silicon thin films. The LPCVD amorphous silicon thin films were completely crystallized after 5 hours at 480 $^{\circ}C$. It is known that needle-like grains with very small width grow in the Ni-metal induced lateral crystallization. In our new method, the width of grains is larger because the grain can also grow perpendicular to the needle growth direction. Also the interface between the merging grain boundaries was coherent. As the results, a polycrystalline film with superior microstructure has been obtained.

• Journal of the Korean institute of surface engineering
• /
• v.28 no.2
• /
• pp.67-76
• /
• 1995

The microstructure of 95wt.%Pb/5wt.%Sn and 63wt.%Sn/37wt.%Pb solders for flip chip bonding process has been characterized. Solders were deposited by thermal evaporation and reflowed in the conventional furnace or by rapid thermal annealing(RTA) process. As-deposited films show columnar structure. The microstructure of furnace cooled 63Sn/37Pb solder shows typical lamellar form, but that of RTA treated solder has the structure showing an uniform dispersion of Pb-rich phase in Sn matrix. The grain size of 95Pb/5Sn solder reflowed in the furnace is about $5\mu\textrm{m}$, but the grain size of RTA treated solder is too small to be observed. The microstructure in 63Sn/37Pb solder bump shows the segregation of Pb phase in the Sn rich matrix regardless of reflowing method. The 63Sn/37Pb solder bump formed by RTA process shows more uniform microstructure. These result are related to the heat dissipation in the solder bump.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.10 s.352
• /
• pp.61-67
• /
• 2006

We developed a constant current source which is insensitive to threshold voltage variation caused by irregular grain boundary distribution in polycrystalline silicon. The proposed current source has superior saturation characteristics over wide range of input voltages as well as small current error compared to the previously reported Vth compensated sources. We measured the circuit performance and error in current due to parameter variation by using HSPICE.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.172-175
• /
• 2006

Effects of deformation at austenite non-recrystallization region and cooling rate on the microstructure and mechanical properties of low carbon (0.06 wt. %) high strength low alloy steels have been investigated. Average grain size decreased and polygonal ferrite transformation promoted with increasing deformation amount due to increase of ferrite nucleation site. As cooling rate increased, the major microstructure changed from polygonal ferrite to acicular ferrite and the fraction of M/A constituents gradually increased. Discontinuous yielding occurred in highly deformed specimen due to the formation of polygonal ferrite. However, small grain size of highly deformed specimen caused lower ductile-to-brittle transition temperature than slightly deformed specimen.

• Journal of the Korean Ceramic Society
• /
• v.32 no.1
• /
• pp.1-10
• /
• 1995

Effects of calcination temperature on microstructure and electric-magnetic properties of Mg-ferrite were investigated. As the calcination temperature increase, the green density and the sintered density increase due to the enhancement of densification of calcined powder. The grain size in the sintered ferrite increases with increasing the calcination temperatures from 800 to 100$0^{\circ}C$, but decreases from 1000 to 120$0^{\circ}C$. The resistivity decreases with increasing the calcination temperatures from 800 to 110$0^{\circ}C$, but increases from 1100 to 120$0^{\circ}C$ due to the microstructure which consists of small, uniform grian size and pores at grain boundaries. Magnetization increases slightly due to the increasement of the sintered density while Curie temperature is almost constant regardless of calcination temperatures.

• Journal of Sensor Science and Technology
• /
• v.5 no.1
• /
• pp.71-77
• /
• 1996

Considering that polycrystalline silicon, a structural material of the micromachining, is affected by a sacrificial oxide layer, the poly-oxide obtained by the thermal oxidation of polycrystalline silicon is newly proposed and estimated as the sacrificial oxide layer. The grain size of the polycrystalline silicon grown on the poly-oxide is larger than that of poly crystalline silicon grown on the conventional sacrificial oxide layer. As a result of XRD, increase of (111) textures and formation of additional (220) textures are observed on the polycrystaIline silicon deposited on the poly-oxide. Also, the polycrystalline silicon grown on the poly-oxide represents small and uniform stress.

• Journal of Powder Materials
• /
• v.7 no.3
• /
• pp.123-130
• /
• 2000

The simulated DUPIC fuel provides a convenient way to investigate fuel properties and behaviours such as thermal conductivity, thermal expansion, fission gas release, leaching and so on. Several pellets simulating the composition and microstructure of the DUPIC fuel were fabricated from resintering powder through the OREOX process of the simulated spent fuel pellets, which were prepared from the mixture of stable forms of constituent nuclides. This study describes the powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using the simulated spent fuel. The homogeneity of additives in the powder was observed after attrition milling. The microstructure of the simulated spent fuel was in agreement with the previous studies. The densities and the grain size of simulated DUPIC fuel was pellets are higher than those of simulated spent fuel pellets. Small metallic precipitates and oxide precipitates were observed on matrix grain boundaries.