• Journal of Animal Science and Technology
• /
• v.51 no.4
• /
• pp.337-342
• /
• 2009

The feasibility of reutilization of magnesium ammonium phosphate (MAP) or struvite slurry recovered from the process through microwave irradiation was studied in this experiment. For this purpose, 4 different operations were performed with or without Mg source addition and different levels of MAP recycled in a batch reactor. Dissolution rate of MAP, ${NH_4}^+$ elimination pattern and physicochemical changes of MAP during microwave irradiation were also studied. The result showed that only 33% orthophosphate ($PO_4-P$) and 27% $NH_4-N$ removal occurred without adding any external Mg source (run A), whereas 87% $PO_4-P$ and 40% $NH_4-N$ removed when 1.0 M ratio of $MgCl_2$ (run B) was added based on $PO_4-P$ in influent. Although the addition of 1.0 molar ratio of microwave irradiated MAP (Run C) removed lower $PO_4-P$ and $NH_4-N$ than 1.0 M $MgCl_2$ (run B), $PO_4-P$ removal was double when compared with no Mg addition (run A). Addition of half MAP and half $MgCl_2$ (run D) showed the similar removal efficiency (88% $PO_4-P$ and 35% $NH_4-N$) with sole $MgCl_2$ addition (run B). Based on these results, the reutilization of MAP irradiated by microwave would be a feasible way to enhance the removal efficiencies of N and P, as well as curtail the Mg chemical usage. Track study showed that $NH_4-N$ gradually increased at initial stage of microwave irradiation of MAP, and then started eliminating from liquor as temperature increased over $45^{\circ}C$. Dissolution rate of ${PO_4}^{-3}$ during microwave irradiation was proportional to the initial MAP concentration, having $0.0091x^{0.6373}$ mg/sec. It was found from the scanning electron microscope (SEM) study that physical structure of MAP crystal started breaking down into small cube granules within very short time by electromagnetic vibration force during microwave irradiation and then gradually melted down into solution.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.4
• /
• pp.50-58
• /
• 2014

Due to the cost burden of new construction, the necessity of repair and retrofitting of aged structures is sharply increasing as the domain of repair and retrofitting construction is expanding. Because of the necessity, new technologies for repair and retrofitting are continuously studied in Korea and foreign countries. Steel adhesive method, fiber reinforced plastic (FRP) surface adhesive method, and external prestressing method are used to perform the repair and retrofitting works in Korea. In order to consider a repair method using steel mesh reinforced cement mortar (SMCM), 3-point flexural member test was conducted considering repair area and layer number of SMCM. Five types of specimens including ordinary reinforced concrete (RC) specimen with dimensions of $1400{\times}500{\times}200$ (mm) were cast for testing the deflection measurement, a LVDT was installed at the top center of the specimens. Also, a steel strain gauge and a concrete strain gauge were placed at the center of the specimens. A steel strain gauge was also installed on the shear reinforcement. The 3 point flexural member test results showed that the maximum load of SMCM reinforced specimen was higher than that of basic RC specimen in all of the load-displacement curves. Also, the results showed that, when the whole lower part of the basic RC specimen was reinforced, the maximum load and strain were 1.18 and 1.37 times higher than that of the basic RC specimen, respectively. Each specimen showed a slightly different failure behavior where the difference of the results was caused by the difference in the adhesive level between SMCM and RC. Particularly, in SM-B1 specimen, SMCM spalled off during the experiment. This failure behavior showed that the adhesive performance for RC must be improved in order to utilize SMCM as repair and retrofitting material.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.10 no.2
• /
• pp.115-124
• /
• 1977

From August 1976 to May 1977, a series of rearing experiments of eels weighing over 5 grams were carried out utilizing indoor recirculating aquariums and the results are summarized as following: 1. The eels were instantly acclimatized in the aquarium when alive Tubifex was fed as food, resulting in the food coefficient of around 5, and the daily growth rate of $2\%$ or so (Table 2). 2. When mackerel flesh was used in combination with flour dough or commercial powdered feed, the food coefficients were 4 to 5 and daily growth rates were between 1 and $2\%$ (Tables 3 and 4). 3. The eels of 12.4-14.7g in average weight which had not shown any growth when fed processed feed, grew normally when they were fed alternately with alive Tubifex and processed feed with the results of 4.3-6.0 in food coefficient and $1.4-2.3\%$ in daily growth rate (Table 5). 4. Experimental processed feed containing North Pacific which fish meal as the main ingredient showed the food coefficient of 1.31-1. 83 as dry material and this means that there is not any significant difference between this experimental feed and the control commercial eel feed, imported front Japan which showed food coefficient of 1.34 and 1.328 (Tables 6 and 7). 5. The feed cost may be reduced by about $45\%$ (based on tile domestic prices in the spring 1977) if this experimental processed feed is used instead of imported commercial feed. 6. Uneven growth is markedly significant in eels, and those which showed retarded growth gave very poor food efficiency as well as poor growth rate until they reach the size of about 30 grams. Thereafter they recovered both the normal food coefficient and growth rate. 7. Individuals which have been showing significant retarded growth may have some inherent physiological factors but this poor growth might also be, more or less, results of some external factors which are considered necessary to be investigated.

• The Journal of Korean Academy of Prosthodontics
• /
• v.53 no.4
• /
• pp.345-351
• /
• 2015

Purpose: The purpose of this study was to evaluate the proper axial thickness of zirconia abutment applied to implant in the anterior region. Materials and methods: Zirconia abutments were prepared at different axial wall thickness by processing pre-sintered zirconia blocks via CAD/CAM to obtain equal specimens. The abutments were each produced with a thickness of 0.5 mm (Group 1), 0.8 mm (Group 2), 1.2 mm (Group 3), or 1.5 mm (Group 4). The implant used in this study was a external connection type one (US, Osstem, Pussan, Korea) product and the zirconia abutment was prepared via replication of a cemented abutment. The crowns were prepared via CAM/CAM with a thickness of 1.5 mm and were cemented to the abutments using $RelyX^{TM}$ UniCem cement. A universal testing machine was used to apply load at 30 degrees and measure fracture strength of the zirconia abutment. Results: Fracture strength of the abutments for Group 1, Group 2, Group 3, and Group 4 were $236.00{\pm}67.55N$, $599.00{\pm}15.80N$, $588.20{\pm}33.18N$, and $97.83{\pm}98.13N$, respectively. Group 1 showed a significantly lower value, as compared to the other groups (independent Mann-Whitney U-test. P<.05). No significant differences were detected among Group 2, Group 3, and Group 4 (independent Mann-Whitney U-test. P>.05). Conclusion: Zirconia abutment requires optimal thickness for fracture resistance. Within the limitation of this study, > 0.8 mm thickness is recommended for zirconia abutment in anterior implants.

• Culinary science and hospitality research
• /
• v.18 no.4
• /
• pp.277-291
• /
• 2012

To compare satisfaction with school meals provided by two different types of school meal services, a survey was conducted with 252 high school students (male: 138, female: 114) consisting of 133 students offered by on-site school meal service and 114 ones by transporting school meal service in Daegu. Anthropometric measurements of the study subjects showed that 68.1% of male and 41.2% of female students had normal weight while 50.0% of female and 10.1% of male students were underweight on the basis of BMIs. 'Taste' was the most important factor when eating meals followed by 'nutrition', 'hygiene' and 'preference by the students'. (of the both schools). Eating habits of the subjects were influenced mostly by family. Female students (17.5%) skipped breakfast more frequently than the male students (8.0%). The students (68.4%) offered by on-site school meal service were more satisfied with meals than those (9.2%) by transporting school meal service. Top reason for not being satisfied was 'taste' in both schools but the second reason (36.3% of the subjects) was 'quantity of food' only in the school with transporting school meal service. In satisfaction with menu, temperature, quantity and hygienic condition of foods, higher dissatisfaction was shown in the students offered by transporting school meal service. Items needed for improvement in school meals suggested by the students were 'taste of food' (25.6% vs 62.2%), 'diversity of menu items' (21.1% vs 8.4%), 'hygienic conditions' (17.3% vs 8.4%), 'quantity of food' (10.5% vs 17.6%) and 'balanced nutrition' (8.4% vs 1.7%) for on-site service and transporting one. It is concluded from these results that transporting meal service for school meals has to be changed from the present condition to improve the quality of meals and that managing and supporting programs should be developed by public institutions such as office of education.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.2
• /
• pp.179-195
• /
• 2010

In the internal connection system, the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. The purpose of this study was to assess the loading distributing characteristics of three different abutments for GS II$^{(R)}$ implant fixture(Osstem, Korea) under vertical and inclined loading using finite element analysis. Three finite element models were designed according to three abutments; 2-piece Transfer$^{TM}$ abutment made of pure titanium(GST), 2-piece GoldCast$^{TM}$ abutment made of gold alloy(GSG), 3-piece Convertible$^{TM}$ abutment with external connection(GSC). This study simulated loads of 100N in a vertical direction on the central pit(load 1), on the buccal cusp tip(load 2) and $30^{\circ}$ inward inclined direction on the central pit(load 3), and on the buccal cusp tip(load 4). The following results were obtained. 1. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture and lower stress was taken at the cancellous bone. 2. When off-axis loading was applied, high stress concentration observed in cervical area. 3. GSG showed even stress distribution in crown, abutment and fixture. GST showed high stress concentration in fixture and abutment screw. GSC showed high stress concentration in fixture and abutment. 4. Maximum von Mises stress in the surrounding bone had no difference among three abutment type. In GS II$^{(R)}$ conical implant system, different stress distribution pattern was showed according to the abutment type and the stress-induced pattern at the supporting bone according to the abutment type had no difference among them.

• Korean Journal of Ichthyology
• /
• v.32 no.3
• /
• pp.166-181
• /
• 2020

The egg development, early life history and spawning site characters of Korean endemic fish, Coreoleuciscus splendidus (Gobioninae), were investigated at the part of Jo-jong stream in Korea from May 2020. The fertilized eggs were 2.05~2.23 mm (mean, 2.13 mm) in diameter and had no oil globules. The embryo began to hatching about 98 hrs after fertilization under water temperature of 20±1℃. The newly-hatched larvae were 5.03~5.68 mm (mean, 5.31 mm) in total length (TL), and their mouth and anus were not opened. 4 days after hatching, Several rod-like cupulae were observed on the head and lateral side of the body at 6.95~7.89 mm (mean, 7.51 mm). 7 days after hatching, the post-larva stage were 8.39~9.29 mm (mean, 8.78 mm) in total length, and their york were completely absorbed. The cupulae were completely distinguished. They entered the juvenile stage when all fin-rays were formed at 29 days after hatching, and their TL were 14.16~17.04 mm (mean, 14.99 mm). Squamation was initiated on the caudal body at approximately 18.21~23.74 mm (mean, 30.28 mm), 38 days after hatching, and completed at 26.82~33.33 mm (mean, 19.42 mm), 73 days after hatching, the external characteristics from of juveniles were same to adults. The spawning site was characterized by bottom structure of pebble (64~16 mm) and gravel (16~2 mm), environmental conditions of the spawning sites were 6~18 cm in water depth, 0.43~0.73 m/sec in bottom water velocity. In spawning sites, an egg mass or separated eggs were located a small gap of under the pebble and gravel.

• Journal of The Korean Association For Science Education
• /
• v.38 no.5
• /
• pp.705-720
• /
• 2018

The purpose of this study is to shed light on the meaning and value of interest (in Korean 'Jae-mi') in science education through literature analysis. Literature analyses were conducted on literature related to interest in various fields such as Korean language, psychology, philosophy, and education. Specifically, this study discussed the meaning of interest, the characteristics of the context of experiencing interest, the educational value of interest in science education, and the direction of science education to realize the value of interest. First, it was found that interest is an experience of emotional activation that can be felt through interaction with a specific object, and it is an emotional experience caused by the complex combination of various psychological factors, which is oriented sense, relationship, self, and object. Second, to understand the context of experience of interest, we conducted a topic modeling analysis with 1173 research articles related to interest. As a result of the analysis, it was confirmed that the context of interest is closely related with playfulness. And we addressed that this kind of playfulness is also found in science. Third, the educational values of interest in science education were discussed. In science education, fun is not only an instrumental value to induce science learning behavior, it is also one of the universal experiences that learners feel lively in science teaching-learning, and driving force of individual students' emotional development related to science. The students' active attitude to feel interest lead to creative thinking and action. Finally, we argued that the interest that should be aimed in science education should be active interest and experienced at trial and error, not passive interest induced by external stimuli. And science education culture should be encouraged to respect those who enjoy science. In particular, this study discussed the importance of each student's unique interest experience based on the philosophy of philosopher Deleuze (1976).

• Applied Biological Chemistry
• /
• v.19 no.4
• /
• pp.202-218
• /
• 1976

In this experiment American Summer Pairman apple was selected as test fruit in order to study the effect of sub-atmospheric pressure storage in the apple. keeping a certain pressure condition, a new sub-atmospheric pressure system was designed and constructed in which fruits were stored at $25^{\circ}C$ under two different atmospheric pressure conditions such as Normal Atmospheric Pressure (NAP) and Sub-Atmospheric Pressure (SAP). Moreover, they were divided into plots of 5% and 0% of $CO_2$, on the basis of gas composition. Under these conditions, the amount of respiration and ethylene evolution, and the changes of intercellular gas composition and organic components were investigated throughout the storage. The results obtained are as follows: (1) The intercellular gas was exhausted so rapidly by the SAP treatment that the gas equilibrium in the tissues reached within 5 minutes. (2) The amount of respiration was found to be higher in plots of NAP than SAP, and under the conditions, controlling $CO_2$ content, plots of $CO_2$ 5% were lower in the amount of respiration than $CO_2$ 0%. The climateric rise was revealed more slowly in plots of the SAP than NAP. These results indicate that the SAP treatment was an efficient method for controlling the respiration of fruits. Furthermore, these results were also realized with the results of the respiratory quotient (R.Q) and intercellular gas composition. (3) Evolution of ethylene, the ripening hormone in plant, was shown the similar tendency to the climacteric pattern of respiration; at the stage of climacteric maximum, the maximun amount of ethylene was found earlier in plots of NAP than SAP, and post climacteric stage was prolonged in the plots of the SAP compared to those of the NAP. The ethylene concentration in tissue appeared lower in plots of the SAP than NAP, which might suggest that the SAP treatment was caused to restriction of ethylene evolution. (4) Effects of the SAP treatment mentioned hitherto were proved also with the test of the external appearance such as changes of color and freshness, firmness, rotting and weight loss. (5) In the investigation of organic components, vitamin C and organic acids varied less in plots of SAP than NAP. Specially, it was remarkable that the loss of malic acid was least decreased by the SAP treatment. These effects of the SAP treatment were distinctive in the changes of the ratios of malic and citric acid to total acid, and the ratios of free sugar to free acid.

• Radiation Oncology Journal
• /
• v.22 no.2
• /
• pp.124-129
• /
• 2004

Purpose : To evaluate the clinical findings, prognosis and treatment strategy of patients with neuroendocrine carcinoma of cervix. Materials and Methods: Thirteen patients with neuroendocrine carcinoma of cervix were included in this study, as confirmed histologically and immunohistochemically at the Dongsan Medical Center, Keimyung University, between May 1944 and October 2001. The mean age of patients was 56 years with a range of 32 to 78 years of age. According to the FIGO staging system, there were 5 patients with stage IB carcinoma, 5 patients with IIA, and 3 patients with stage IIB. Four patients underwent radical hysterectomy with pelvic lymphadenectomy, 3 of these patients also received postoperative radiotherapy, and one patient underwent extrafascial hysterectomy after radiotherapy. Primary radiotherapy was done in 9 patients, and 3 were irradiated postoperatively. Nine patients received chemotherapy, 7 received neoadjuvant and 2 received concurrent chemoradiotherapy. The radical purpose of radiotherapy consisted of external irradiation to the whole pelvis (4,500 $\~$5,400 cGy) and intracavitary irradiation (3,000 $\~$ 3,500 cGy). Results : The mean follow up duration was 36 months with a range of 3 to 104 months. The overall 5-year survival rate was 61.5$\%$ and the 5-year survival rates for stage IB, IIA, IIB were 60.0$\%$, 60.0$\%$, and 66.7$\%$ respectively (p=0.99). Eight patients are still alive without disease, and all of the 5 patients with recurrence are dead due to distant metastasis. Conclusion : Neuroendocrine carcinoma of cervix is highly aggressive, with early lymphatic dissemination and a high rate of distant recurrence. Therefore, an aggressive therapeutic strategy Is required to obtain pelvic and distant disease control. Multimodal therapy should be considered at the time of Initial diagnosis.