• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.278-278
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• 2022

Recently, the yield potential of high yield Tongil-type rice varieties has greatly increased, reaching 817kg/10a(Geumgang No.1). Moreover, in order to promote rice consumption and strengthen the competitiveness of the rice processing industry, the R&D of high yield Tongil-type rice varieties for each processing purpose, such as rice noodles, grain feed and industrial materials, has been continuously carried out. However, because Tongil-type rice varieties or lines are generally very vulnerable to cold damage, cold tolerance test can be said to be absolutely necessary to improve the cultivation safety. This study is the result of the seedling and field cold tolerance characteristic tests carried out in 2021 of high yield Tongil-type rice breeding lines. For the cold tolerance characteristic test of seedlings, total 303 high yield rice breeding lines for processing were treated in cold water of 13℃ and irrigation depth of 4cm for 10 days from the third-leaf age, then it was evaluated by comparing the degree of discoloration and withering with the checked varieties(Boramchan, Hanahreum No.2). Also, for the test of field, total 186 high yield rice breeding lines for processing were treated in cold water of 17℃ by keeping pouring day and night from 30 days after transplanting to ripening stage, then it was evaluated by comparing the degree of discoloration, delay of heading, shortening rate of stem length and percent of fertile grain etc. with the checked varieties. And the cold tolerance evaluative criteria were classified as strong(1~3), medium(4~6) and weak(7~9) in overall cold tolerance. (Seedling test) As for the degree of cold tolerance of the check variety, 'Boramchan' and 'Hanahreum No.2' showed a response of 'medium' and 'weak', respectively. However, there was no 'strong' line in the high yield rice breeding lines, 2 lines showed a 'medium' response, and 301 lines showed a 'weak' response. Therefore, except for a few lines(0.7%), most lines(99.3%) showed a 'weak' response. (Field test) In terms of the overall cold tolerance of the check variety, both 'Boramchan' and 'Hanahreum No.2' showed a 'medium' response. Similarly, there was no 'strong' line in the case of high yield rice breeding lines, 20 lines showed a 'medium' response, and 166 lines showed a 'weak' response. Therefore, except for some(10.8%) lines, most(89.2%) lines showed a 'weak' response. From the above results, we selected about 100 individuals with less seed shattering and degeneration of the ear tip, and with a relatively high percent of fertile grain, and are continuing to select lines with improved cold tolerance in the F4~F5 group in this year. As such, most of the Tongil-type rice varieties have poor cold tolerance and thus have low cultivation safety at low temperatures. However, it is important to select improved lines through generational progress because there are some lines that still have a certain level of cold tolerance among them.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.744-751
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• 2007

Wet scrubber is widely used to remove toxic gaseous contaminants in various industries such as semi-conductor industry, display manufacturing industry and so on. In this study, to optimize a packed bed scrubber as one of typical wet scrubber size while keeping its performance, four different packing materials were investigated at different air flow rates, liquid-gas ratios and pH values. Ammonia, hydrochloric acid and hydrofluoric acid were used as test gases to characterize the scrubber performance. Gas removal efficiency increased as the packing size decreased, which resulted in the increase of specific surface area. The increase of air flow rate led to the decrease of gas removal efficiency, while the increase of liquid-gas ratio led to the increase of gas removal efficiency. For the case of $NH_3$ gas, lower pH, and for the cases of HCl and HF, higher pH contributed to higher gas removal efficiency. Gas removal efficiency of a wet scrubber increased in the order of HCl < $NH_3$ < HF according to its water solubility.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.488-503
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• 2012

The stern boat deployment system was investigated to evaluate the capability of launching and recovering rigid hull inflatable boat (RHIB) via the stern ramp. The main parameters to launch and recover RHIB were tested at the design stage. The combined hydrodynamic effect of the stern wake and the water jet flow made it difficult to maintain the maneuvering and sea-keeping ability of RHIB approaching to the stern ramp. The safe recovery course was proposed to maintain the directional control of RHIB and to reduce the combined hydrodynamic effect in the transom zone. To evaluate the feasibility of RHIB recovery, the stern sill depth was measured in various conditions and the ramp availability time was obtained. Also, the experimental percent time operability (PTO) test was performed by the number of successive launching and recovering operations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.99-106
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• 1982

Vacuum-packed and seasoned-dried products of filefish, Navodon modestus, caught in large quantities in the coasts of Japan and Korea, were prepared tentatively and stored at $35^{\circ}C$ for $3\sim4$ months to test their keeping quality. Headed, eviscerated, ana skinned filefish were purchased from Tokyo central wholesale market and filleted. The fillets were seasoned with the seasoning powder prepared from sugar, sorbitol, salt, glutamate, 5'-ribonucleotide, and either beef flavor (Flava-Beef, Kyowa Hakko Kogyo Co. Ltd.), red pepper, or smoke flavor (Smok-EZ, Alpha Foods Co. Ltd.). After seasoning, the fillets were dried at $39\sim41^{\circ}C$ for several hours, vacuum-packed in the bag of plastic film, and cooked in water of $80^{\circ}C$ for 40 min. Two kinds of products different in moisture level were prepared : one containing moisture of $26\sim29\%$ and the other $40\sim46\%$. The moisture level, water activity, color value (L,a, and b values), texture, and viable counts of bacteria of these products were determined during storage at $35^{\circ}C$. From the results obtained, it became clear that the products could be preserved in good condition for $3\sim4$ months at $35^{\circ}C$, though they slightly decreased in the softness with decrease of moisture content and developed a pale brown during storage. Judging from organoleptic evaluation on the flavor, the products containing beef flavor as a seasoning was most desirable.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.355-362
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• 1983

A vacuum-packed seasoned-dried product of sea mussel, Mytilus edulis, caught in the southern coasts of Korea, was prepared and stored at $35^{\circ}C$ for 70 days to test quality stability. Sea mussel, purchased from Jagalchi fish market in Busan, was steamed, shucked and eliminated byssus. The sea mussel meat was seasoned with the seasoning solution prepared with sugar, salt, sorbitol, glycerol, monosodium glutamate, 5'-ribonucleotide and smoke flavor (Smoke-EZ, Alpha Foods Co., Ltd.). After seasoning, the meat was dried at $52-58^{\circ}C$ for three hours, vacuum-packed in the laminated plastic film bag($14{\times}15cm$), and finally sterilized at $120^{\circ}C$ for 26 minutes in hot water circulating retort. The moisture, water activity, color value(L, a and b value), texture, TBA value and viable bacterial count of the products were determined during the period of storage at $35^{\circ}C$. From the results obtained, it became clear that the product could be preserved in a good quality for 70 days at $35^{\circ}C$, though a slight decrease in moisture content and development of a pale brown color was resulted. Judging from the sensory evaluation on flavor, the products containing smoke flavor were most desirable.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.255-263
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• 2004

One of the best way to prevent dental caries and periodontal disease is removing dental plaque. Toothbrushing is also one of the crucial ways to gel rid of dental plaque and improve dental hygiene. The purpose of th is study was to examine how many bacteria were attached to toothbrushes used by dental palque acidogenecity and related behaviors to toothbrush use. Subjects in this study were 30 college students in their twenties, on whom a survey was conducted to find out how they cleansed their toothbrushes, how long they cleaned toothbrushes after brushing, and how to keep them. And then dental palque acidogenecity by caries activity test was implemented and the number of bacteria attached to their toothbrushes was tested. The findings of the study were as follows : 1. Concerning correlations between dental palque acidogenecity and the number of remaining bacteria in the toothbrushes used by students, the number of bacteria was lower in the group of students with no caries activity than in the group with mild caries activity. 2. As for relations between the way of cleansing toothbrushes and the number of bacteria, there was no statistically significant gap between the group of students who wetted their toothbrushes with water and rubbed the heads of them and the group of students who just only wetted their toothbrushes with no further actions. 3. Regarding the relationship of toothbrush cleansing time to the number of bacteria, the number of bacteria was lower in the group of students who cleansed their toothbrushes for 15 seconds or more. 4. As to the influence of the number of toothbrush used by students, there was no significant difference between the group using just one toothbrush and the other group using two or more toothbrushes. 5. As for correlations between the way of keeping toothbrushes and the number of bacteria, no significant gap existed between the group thai kept their toothbrushes separately and the other that didn't.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.401-414
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• 2018

Planing hull type ships are often equipped with interceptor or trim tab to improve the excessive trim angle which leads to poor resistance and sea keeping performances. The purpose of this study is to design a controller to control the attitude of the ship by controllable stern interceptor and validate the effectiveness of the attitude control by the towing tank test. Embedded controller, servo motor and controllable stern interceptor system were equipped with planing hull type model ship. Prior to designing the control algorithm, a model test was performed to identify the system dynamic model of the planing hull type ship including the stern interceptor. The matrix components of model were optimized by Genetic Algorithm. Using the identified model, PID controller which is a classical controller and sliding mode controller which is a nonlinear robust controller were designed. Gain tuning of the controllers and running simulation was conducted before the towing tank test. Inserting the designed control algorithm into the embedded controller of the model ship, the effectiveness of the active control of the stern interceptor was validated by towing tank test. In still water test with small disturbance, the sliding mode controller showed better performance of canceling the disturbance and the steady-state control performance than the PID controller.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.171-179
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• 2009

The porosity in porous media like concrete can be considered as a durability index since it may be a routine for the intrusion of harmful ions and room for the keeping moisture. Recently, modeling and analysis techniques for deterioration are provided based on the pore structure with the significance of durability and the relationship between porosity and durability characteristics is an important issue. In this paper, a series of mortar samples with five water to cement ratios are prepared and tests for durability performance are carried out including porosity measurement. The durability test covers those for compressive strength, air permeability, chloride diffusion coefficient, absorption, and moisture diffusion coefficient. They are compared with water to cement ratios and porosity. From the normalized data, when porosity increases to 1.45 times, air permeability, chloride diffusion coefficient, absorption, and moisture diffusion coefficient decrease to 2.3 times, 2.1 times, 5.5 times and 3.7 times, respectively, while compressive strength decreases to 0.6 times. It was evaluated that these are linearly changed with porosity showing high corelation factors. Additionally, intended durability performances are established from the test results and literature studies and a porosity for durable concrete is proposed based on them.

• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.155-164
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• 1995

This study was performed to get high strength of the precase concrete adopting a steam curing by using a gypsum-admixture for the high strength concrete. The superplasticizer was used to compensate low slump of base concrete keeping its slump up about $6{\pm}1cm$. To examine the property for strength revelation of concrete using admixtures for a high strength concrete, steam and standard curing were compared each other. Test results were shown that admixtures for high strength concrete were more effective in steam curing than standard curing. On the condition that the unit cement content is about $530{\sim}600kg/m^3$, the compressive strength of concrete replacing by 10% of the admixture was obtained over $65Okgf/cm^2$, which was increased as 1.3 times as that for the nonreplacement. When the admixture was replaced to 15-30%, the compressive strengh was obtained over $700kgf/cm^2$ which was increased as 1.4 - 1.5 times. Therefore, the admixture for high strength concrete, being effective in steam curing, was more efficient to get a high strength concrete using only steam curing instead of an autoclave curing for the secondary products of cement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1033-1036
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• 2002

Wafer bonding methods such as fusion and anodic bonding suffer from high temperature treatment, long processing time, and possible damage to the micro-scale sensor or actuators. In the localized bonding process, beating was conducted locally while the whole wafer is maintained at a relatively low temperature. But previous research of localized heating has some problems, such as non-uniform soldering due to non-uniform heating and micro crack formation on the glass capsule by thermal stress effect. To address this non-uniformity problem, a new heater configuration is being proposed. By keeping several points on the heater strip at calculated and constant potential, more uniform heating, hence more reliable wafer bonding could be achieved. The proposed scheme has been successfully demonstrated, and the result shows that it will be very useful in hermetic packaging. Less than 0.2 ㎫ contact Pressure were used for bonding with 150 ㎃ current input for 50${\mu}{\textrm}{m}$ width, 2${\mu}{\textrm}{m}$ height and 8mm $\times$ 8mm, 5mm$\times$5mm, 3mm $\times$ 3mm sized phosphorus-doped poly-silicon micro heater. The temperature can be raised at the bonding region to 80$0^{\circ}C$, and it was enough to achieve a strong and reliable bonding in 3minutes. The IR camera test results show improved uniformity in heat distribution compared with conventional micro heaters. For gross leak check, IPA (Isopropanol Alcohol) was used. Since IPA has better wetability than water, it can easily penetrate small openings, and is more suitable for gross leak check. The pass ratio of bonded dies was 70%, for conventional localized heating, and 85% for newly developed FP scheme. The bonding strength was more than 30㎫ for FP scheme packaging, which shows that FP scheme can be a good candidate for micro scale hermetic packaging.