• Korean Journal of Veterinary Research
• /
• v.6 no.1
• /
• pp.24-30
• /
• 1966

In order to observe the effect of the injected radioactive iodine-$I^{131}$ on the uptake in thyroid of normal male guinea pigs and P.B.$I^{131}$ conversion ratio of $I^{131}$ in serum, 24 matured male guinea pigs were divided in 4 groups and $35{\mu}c$, $70{\mu}c$, $140{\mu}c$ and $280{\mu}c$ per kg of body weight respectively were injected subcutaneously. 1. The uptake rates of radioactveiodine-$I^{131}$ by external counts of thyroidal uptake reached the maximum level of uptake in 24 hours after injection. 2. As the injected amount increases, the uptake rates of maximum levels and release rate were increased. 3. Uptake rate in the removed thyroid have shown no statistical in the $35{\mu}c$ and $70{\mu}c$ groups of injected guinea pigs. 4. There was no statistical significance in $140{\mu}c$ and $280{\mu}c$ groups of injected guinea pigs. 5. P.B.$I^{131}$ conversion ratio of $I^{131}$ in serum was not in proportion to injected amounts: 61.0%(35), 70.2%(70), 75.3%(140) and 64.8%(280).

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.24 no.5
• /
• pp.213-218
• /
• 2014

An investigation of the influence of $WO_3$ addition with different precursors and preparation methods on the phase formation and selective catalytic reduction (SCR) efficiency of anatase-$TiO_2$ powders has been carried out. An anatase-$TiO_2$ synthesized by precipitation process was used as a catalyst support. For $WO_3(10wt%)/TiO_2$, the W loading to the $TiO_2$ support led to the lower in anatase to rutile transition temperature to ${\sim}900^{\circ}C$ from $1200^{\circ}C$ of the $TiO_2$ support alone. In the case of $WO_3(10wt%)/TiO_2$ SCR powders obtained from a wet process with ammonium meta-tungstate (AMT) precursor, the highest $NO_X$ conversion efficiency was achieved at $450^{\circ}C$ remaining high efficiency at $500^{\circ}C$, while the same composition prepared from a dry process with $WO_3$ addition showed the lowered efficiency with temperature after reaching the efficiency maximum at $350^{\circ}C$. The same tendency has been found that the $V_2O_5(5wt%)-WO_3(10wt%)/TiO_2$ SCR powders obtained from the wet process with AMT precursor has shown the superior $NO_X$ conversion efficiency over 90 % in a wider temperature range of $300{\sim}500^{\circ}C$.

• Journal of ILASS-Korea
• /
• v.24 no.4
• /
• pp.163-170
• /
• 2019

In this study, feedback logic using dual O₂ sensor values were developed to increase the purification capability of a three-way catalyst (TWC) in a compressed natural gas (CNG) engine. A heavy-duty inline 6-cylinder engine was used and the CNG was supplied to the engine through a mixer. This study consists of two main parts, namely, the proportional integral (PI) control with a front O₂ sensor and the feedback control with dual O₂ sensors. In the PI control experiment, effects of various parameters, such as P gain, I gain, and lean delay, on the TWC capability were identified. Based on the results of the PI control experiment, the feedback logic using dual O₂ sensor values were developed. In both cases, the nitrogen oxides (NO_X) emissions were nearly zero. However, the carbon monoxide (CO) emissions were reduced significant in the feedback logic with dual O₂ sensors than in the PI control with the front O₂ sensor.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.4
• /
• pp.539-548
• /
• 2016

The objective of the present study was to investigate the influence of palm kernel meal (PKM) inclusion and exogenous enzyme supplementation on growth performance, nitrogen-corrected apparent metabolizable energy (AMEn), coefficient of apparent ileal digestibility (CAID) and total tract retention of nutrients in young broilers fed corn-based diets. Four inclusion levels of PKM (no PKM [PKM0], 8% [PKM8], 16% [PKM16], and 24% [PKM24]) and two enzyme additions were evaluated in a $4{\times}2$ factorial arrangement of treatments. A total of 384, one-d-old male broilers (Ross 308) were individually weighed and allocated to 48 cages (eight broilers/cage), and cages were randomly assigned to eight dietary treatments. Results indicated that the inclusion of 8% and 16% PKM increased (p<0.05) the weight gain compared to the PKM0 diet. Birds fed the PKM8 diets had the highest (p<0.05) feed intake. Weight gain and feed intake were severely reduced (p<0.05) by feeding the PKM24 diet. Enzyme supplementation increased weight gain (p<0.05), independent of PKM inclusion level. In PKM0 and PKM8 diets, enzyme addition significantly (p<0.05) lowered feed conversion ratio (FCR); whereas enzyme addition had no effect on FCR of birds fed PKM16 and PKM24 diets. In PKM0 and PKM16 diets, enzyme addition significantly (p<0.05) increased CAID of nitrogen and energy but had no effect in the PKM8 and PKM24 diets. Inclusion of PKM into the basal diet, irrespective of inclusion level, enhanced (p<0.05) starch and fat digestibility. Inclusion of PKM at 16% and 24% resulted in similar CAID of neutral detergent fiber (NDF) but higher (p<0.05) than that of the PKM0 and PKM8 diets. Enzyme addition, regardless of the level of PKM inclusion, significantly (p<0.05) increased CAID of NDF. There was a significant (p<0.05) decrease in AMEn with PKM inclusion of 24%. The present data suggest that inclusion of PKM in broiler diets could be optimized if PKM-containing diets are formulated based on digestible amino acid contents and supplemented with exogenous enzymes. If amino acid digestibility and AME of PKM considered in the formulation, it can be included in broiler diets up to 16% with no deleterious effects on growth performance.

• Korean Journal of Poultry Science
• /
• v.24 no.1
• /
• pp.39-44
• /
• 1997

Two experiments were carried out to determine the effects of pelleting layer diets on the laying perforrnance and nutrients utilizability, using either 50-wk-old(Experiment 1) or 80-wk-old (Experiment 2) layers. There was no effect of pelleting layer diets on hen-day egg production and average egg weight but decreased (P<0.05) feed conversion ratio(intake /egg weight) in both experiments. Although both egg specific gravity and eggshell thickness were not influenced by pelleting eggshell breaking strength was improved(P<0.05) only in Experiment 1. Utilizability of dietary fat was improved(P<0.05) by pelleting layer diets with no difference in other nutrients utilizability. There was no difference in the passage rate of mash and pelleted layer diets.

• Journal of Korean Elementary Science Education
• /
• v.38 no.4
• /
• pp.484-495
• /
• 2019

This study divided pre-service elementary school teachers' knowledge conversion into four types, socialization, externalization, combination and internalization, based on their inquiry activities on the life cycle of cabbage butterfly. As research subjects, this study collected results from 24 pre-service elementary school teachers who carried out inquires on the life cycle of cabbage butterfly for about 2 months. The type of socialization indicates the conversion of tacit knowledge into tacit knowledge, and this study found out that pre-service elementary school teachers acquired and accumulated tacit knowledge from their fellow pre-service teachers, professors and even acquaintances inside and outside the lab. However, there appeared no process that they shared their tacit knowledge with other pre-service teachers or delivered it to them. The type of externalization indicates the conversion of tacit knowledge into explicit knowledge, and this study discovered some cases that pre-service elementary school teachers expressed their inner tacit knowledge into explicit knowledge. However, there was no case found that they converted the verbally-unexpressed tacit knowledge of their fellow teachers or experts into well-defined explicit knowledge. The type of combination indicates the conversion of explicit knowledge into explicit knowledge, and this study discovered some cases that they collected explicit knowledge and converted it into new explicit knowledge for the acquisition, integration and delivery or distribution of explicit knowledge. However, there were few cases that they creatively devised new explicit knowledge by acquiring new knowledge through direct observation and supplementing the existing explicit knowledge. The type of internalization indicates the conversion of explicit knowledge into tacit knowledge, and this study discovered both explicit knowledge embodied through personal experiences and explicit knowledge embodied through simulations and experiments that formed tacit knowledge in process of examining the existing explicit knowledge.

• Journal of Korean Society of Water and Wastewater
• /
• v.14 no.2
• /
• pp.196-206
• /
• 2000

Methanogenesis and denitrification in an upflow sludge baffled filter (UBF) reactor were studied using glucose as a fermentative substrate. Experiments were carried out to investigate how to reduce ammonification by changing alkalinity and $COD/NO_3-N$ ratio. Characteristics of granular sludges were examined by specifics methanogenic activity(SMA) and specific denitrification rate(SDR) tests. Microstructures of granules were examined using a scanning electron microscopy(SEM). It was found that COD was removed efficiently owing to the diverse microorganisms. In nitrate conversion, not only $COD/NO_3-N$ ratio but also influent alkalinity played important role in the ratio of denitrification and ammonification of nitrate. This reactor achieved over 95% COD and 99% nitrate removal efficiencies when influent contained 4000 mgCOD/L and $700mgNO_3-N/L$ at the hydraulic retention time of 24 hours. As $COD/NO_3-N$ ratio decreased, granular methanogenic activities using acetate and butyrate as substrates increased while activities using propionate and glucose decreased. There were three types in granules according to the surface color; gray, yellowish gray, and black. Gray or yellowish gray-colored granules were composed two layers, which were composed of black inner side and gray or yellowish gray surface substances. SEM illustrated that both were rod-type and cocci-type microorganisms resembling Methanothrix sp. and Methanococci sp. This study showed that by controlling the influent alkalinity and $COD/NO_3-N$ ratio, ammonification and denitrification could be manipulated.

• Korean Journal of Poultry Science
• /
• v.40 no.1
• /
• pp.17-23
• /
• 2013

This work was carried out to investigate the performance of early laying period of large-type Korean native ducks. One hundred sixty eight ducks were used in this work and divided into A and B strains (6 replications/strain, 14 birds/replication). The days at first egg of A and B strains were the age of 154.5 and 154.7 days, egg weights were 69.1 g and 65.5 g, and body weights were 3,187 g and 3,105 g at the period of laying the first egg, respectively. The days at sexual maturity of A and B strains were the age of 175.8 and 171.5 days, egg weights were 75.2 g and 74.9 g, and body weights were 3,245 g and 3,225 g at the period of laying the first egg, respectively. There were no significant differences on the day of first egg, the day of sexual maturity, egg weight and body weight at first egg and the sexual maturity, average body weight, and daily feed intake between A and B strains (P>0.05). The day of the sexual maturity of B strain was earlier than that of A strain (P<0.05). However, weekly body weight was the highest at the age of 28 weeks (P<0.05), and weekly feed intake increased after 26 weeks old (P<0.05). Egg production (%) of B strain was higher than that of A strain at the age of 22~24 weeks (P<0.05), but there was no significant difference on egg production (%) the other weeks. A number of egg laid of B strain was higher than A strain at 22~24 weeks old (P<0.05). Feed conversion ratio of A and B strains were 10.7 and 6.53 at 24~24 weeks old, respectively, so feed conversion ratio of A strain was higher than that of B strain (P<0.05). Weekly feed conversion ratio wes the highest at 20~22 weeks old, and significantly decreased until 24~24 weeks old, but were lowly maintained from the age of 24 weeks to the age of 30 weeks. These results provided the basic data on the record of early laying period of large-type Korean native ducks.

• ETRI Journal
• /
• v.24 no.2
• /
• pp.131-141
• /
• 2002

This paper considers a routing and wavelength assignment problem (RWAP) for the implementation of efficient Wavelength Division Multiplexing all-optical mesh networks without wavelength conversion. For a given physical network and required connections, the solution to the RWAP consists in how to select a suitable path and wavelength among the many possible choices for each connection so that no two paths using the same wavelength pass through the same link, while minimizing the number of required wavelengths. We introduce an integer programming formulation of the RWAP, which has an exponential number of variables, and propose an algorithm to solve it based on the column generation technique. The proposed algorithm can yield high quality solutions and tight lower bounds at the same time. Though the proposed algorithm cannot guarantee optimal solutions, computational results show that the algorithm yields provably good solutions within a reasonable time.

• Korean Journal of Pharmacognosy
• /
• v.24 no.2
• /
• pp.131-139
• /
• 1993

These studies were conducted to investigate the effects of the extracts from Hoelen alba, Alismatis Rhizoma and Atractylodes Rhizoma on the proliferation and differentiation of 3T3-L1 cells. The results were summerized as follows: Hoelen alba and Alismatis Rhizoma extracts inhibited the proliferation of preadipose 3T3-L1 cells. In inductive differentiation, all three extracts inhibited the adipose conversion in 2 days of initial-culture, Atractylodes Rhizoma extract inhibited the adipose conversion in 5 days of final-culture and Hoelen alba and Alismatis Rhizoma inhibited adipose conversion in treatment of whole term of culture. In spontaneous differentiation, Atractylodes Rhizoma extract increased the adipose conversion in 2 days of initial-culture, Hoelen alba and Alismatis Rhizoma increased the adipose conversion in 5 days of final-culture, all three extracts increased adipose conversion in treatment of whole term of culture. The 10% serum of mice treated with each sample did not affect, but the 5% serum of them inhibited the proliferation of 3T3-L1 cells. In inductive differentiation, the 10% serum of them inhibited the adipose conversion in treatment of whole term of culture.