• Food Engineering Progress
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• v.23 no.4
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• pp.283-289
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• 2019

This study was performed to determine the effect of psyllium husk addition on the physical properties of rice extrudates. Rice-based formulations mixed with psyllium husk (0, 7, 14 and 21%) were extruded at a die temperature of 140℃, screw speed of 200 rpm, and moisture content of 20%. As the content of psyllium husk increased, expansion ratio decreased, while piece density and specific length increased. Apparent elastic modulus, breaking strength, adhesiveness, and hardness augmented with an elevation in psyllium husk content. Lightness declined as psyllium husk content furthered, while redness, yellowness, and color difference intensified. Water soluble index and water absorption index increased with an increased amount of psyllium husk. In conclusion, the addition of psyllium affected the expansion of extruded rice snack possessing hard texture, small cells, and sticky texture due to higher water absorption during hydration.

• International Area Studies Review
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• v.14 no.2
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• pp.43-60
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• 2010

This paper measures R&D efficiency and productivity changes of 24 nations including Korea, Japan and China by the non-parametric Malmquist productivity index. The principle findings of this study are as follows. First, R&D efficiency scores of Korea and Japan are 0.837 and 0.834 respectively. Meanwhile China shows 0.420, the worst performance among the selected countries. Second, Korea marked annual productivity increase of 25%, highest among the selected countries', for 2000-2005. R&D productivity in Japan and China, however, decreased 1.9% and 0.9% respectively. Third, annual rates of technology change and technical efficiency change in Japan are 0.6% and -2.5%. Therefore decrease of productivity in Japan is mainly due to technical inefficiency. In case of China, improvement of technical efficiency is the main contributor to productivity growth but technical progress has edged downward in the sample period. In Korea, with annual rate of technology change and technical efficiency change being 5.2% and 18.2% respectively, both efficiency improvement and technical progress has pulled the R&D productivity growth.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.14 no.1
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• pp.36-40
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• 2018

CATCH22 syndrome or DiGeorge syndrome is a medical acronym of cardiac defects, abnormal facial appearances, thymic hypoplasia, cleft palate, and hypocalcemia. Patients with CATCH22 syndrome are susceptible to infection due to an absent or hypoplastic thymus and often have difficulties in maintaining good oral hygiene, which may require dental treatment. We present a case of dental treatment for the uncooperative child with CATCH22 syndrome under general anesthesia. A 4-year-old, 14.8 kg boy with CATCH22 syndrome visited Seoul National University Dental Hospital for dental check up. The patient had multiple caries requiring dental treatment. He experienced the corrective heart surgery due to Tetralogy of Fallot a few years ago. General anesthesia was planned because his heart rate and vital sign had shown unstable during the previous conscious sedation procedure. Dental restorative treatments were successfully performed and no complications were observed during and after the procedure. Safe and effective dental management of the patients with CATCH22 syndrome could be performed with the help of general anesthesia and careful monitoring.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.751-758
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• 2017

The objective of this study was to determine the effects of moisture content and screw speed on the physical properties of extruded soy protein isolate (SPI). Expansion index, water absorption index, texture, integrity index, color, and nitrogen solubility index of extruded SPI were analyzed to determine the relationship with extrusion conditions. Extrusion conditions were moisture content (40, 50, and 60%) at a fixed die temperature ($140^{\circ}C$) and screw speed (250 rpm). The other extrusion conditions were screw speed (150, 250, and 330 rpm) at a fixed moisture content (55%) and die temperature ($140^{\circ}C$). Specific mechanical energy (SME) input decreased as moisture content increased from 40 to 60%. However, SME input increased as screw speed increased from 150 to 330 rpm. Expansion ratio and piece density decreased as moisture content and screw speed increased, and specific length increased as moisture content and screw speed increased. The extruded SPI at 40% moisture content had higher water absorption index, texture, and color differences than those of the extruded SPI at other moisture contents (50 and 60%). however, the extruded SPI at 40% moisture content had lower integrity index and cutting strength than those of the extruded SPI at other moisture contents (50 and 60%). In conclusion, the physical properties of extruded SPI were more affected by moisture content than screw speed.

• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.64-70
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• 2006

Purpose : The natural courses of prenatally diagnosed hydronephrosis(HN) are diverse. Our purpose was to determine if the findings of renal ultrasonography(USG) in patients with prenatal HN at 1 month of age can predict the 1 year follow-up results and determine the guideline of follow-up study. Methods : Among 462 hydronephrotic patients registered between 1996 and 2004, 153 unilateral hydronephrotic renal units were enrolled in this study, bilateral HN, vesicoureteral reflux and other associated anomaly were excluded. These were classified into four groups respectively, according to anterior posterior pelvic diameter(APPD) or Society for Fetal Urology(SFU) grading by USG findings at 1 month after birth. Renal USG and $Tc^{99m}$-mercaptoacetyl triglycerine(MAG3) scan were done according to a set protocol. Results : Most cases improved or remained stationary. No one underwent an operation SFU grade 1,2 groups and only one case of SFU grade 3 group was operated. Thirty two cases(64 percent) were operated on among the 50 cases of SFU grade 4 group. 0/2(0 percent), 5/11(45.5 percent), 11/17(64.7 percent) and 16/20(80 percent) were operated on in each group with APPD <10, 10-19, 20-29, >30 mm, and the operation risk is higher as the APPD is increased. Conclusion : In group with SFU grade below 3 and APPD below 10 mm, we can delay the follow-up study beyond existing set protocol. Operations are recommended immediately if diuretic renogram show the obstructive pattern or decreased renal function in SFU grade 4 group with APPD over 10 mm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12A
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• pp.1229-1237
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• 2006

IEEE 802.11 has employed distributed coordination function (DCF) adopting carrier sense multiple access with collision avoidance (CSMA/CA). To effectively resolve collisions, DCF uses binary exponential backoff (BEB) algorithm with three parameters, i.e., backoff stage, backoff counter and contention window. If a collision occurs, stations involving in the collision increase their backoff stages by one and double their contention window sizes. However, DCF with BEB wastes wireless resource when there are many contending stations. Therefore, in this paper, to enhance the performance of wireless LAN, we propose binary negative-exponential backoff (BNEB) algorithm which maintains a maximum contention window size during collisions and reduces a contention window size to half after successful transmission of a frame without retransmissions. For IEEE 802.11, 802.11a and 802.11b standards, we also compare the performance of DCF with BEB to that with BNEB.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.10-18
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• 2014

This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.463-469
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• 1988

The effects of moisture content and particle size of rice flour on the physical properties of the extrudate were examined by using a autogeneous single screw extruder. The moisture contents tested were in the range of 17-28% and the particle sizes were 18-60mesh and 60-120mesh. Samples were taken at different temperatures from the start-up period to the steady state operation. The expansion ratio increased and bulk density decreased as the moisture content and particle size of the flour decreased. The cutting force decreased and the air cell size became uniform as the moisture content and particle size of the flour decreased. As the moisture content increased, the yellowness of the extrudate powder decreased, while the lightness increased, the apparent viscosity increased and the water soluble index decreased. Gelatinization and partial dextrinization were apparent during the extrusion process, and the degree of dextrinization was appeared to be influenced by the levels of moisture content and particle size of rice flour.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1716-1723
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• 2014

This study was designed to examine the change in physical properties of extruded brown rice-vegetable mix at different pregelatinized brown rice contents and $CO_2$ gas injection. Moisture content, screw speed and die temperature were fixed to 30%, 100 rpm and 60, respectively. $CO_2$ gas injection was adjusted to 0, 300, 600, and 800 mL/min. The content of vegetables (carrot, pumpkin, kale and Angelica keiskei) mix was fixed 5%. Pregelatinized and raw brown rice powder were blended as the ratio of 0/95, 30/65 and 50/45. Specific mechanical energy input decreased as pregelatinized brown rice ratio increased. Expansion index increased and the size and number of pores increased but density decreased with the increasing in $CO_2$ gas injection. Gelatinization degree increased as $CO_2$ gas injection increased. In conclusion, cold extrusion with $CO_2$ gas injection at $60^{\circ}C$ die temperature could be applied for Saengsik (uncooked food) making.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.947-954
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• 1997

Selected physical properties of cornmeal extrudates fortified with dairy products and extrusion process by $CO_2$ gas injection were analysed. Dairy products including whole milk powder, whey protein concentrate non-fat dry milk, and sodium caseinate were tested at the addition of 10% and 20%, based on cornmeal weight. $CO_2$ gas was injected to the barrel at the pressure of 0.7 and 1.4 MPa. Specific mechanical energy (SME) input was decreased by the addition of dairy products. Sodium caseinate had a little effect on decreasing the SME input, however whole milk powder tremendously reduced SME input when the concentration increased. An increase in milk product content resulted in increasing the piece density at the injection pressure of 0.7 MPa. At both 10% and 20% milk product content, the piece density was lowest at the injection pressure of 0.7 MPa. The sectional expansion index was highest at the injection pressure of 0.7 MPa. However, the specific length was constantly increased with the increase in $CO_2$ injection pressure. Water absorption index was decreased and water solubility index was increased by the addition of milk products. The injection pressure of $CO_2$ was optimum at 0.7 MPa. The addition of whole milk powder limited to puff the melt, but the other milk products tested resulted in puffing with $CO_2$ injection to 1.4 MPa.