• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.21 no.3
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• pp.174-181
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• 2010

Objectives: To identify the factors affecting long-term adherence to methylphenidate treatment in children with attention-deficit hyperactivity disorder (ADHD). Methods: A retrospective medical record review of 239 ADHD patients (mean age $9.3{\pm}2.6$ years, range 6.0-17.4 years) who had visited the child and adolescent psychiatry clinic at a university hospital, in Seoul, Korea from March 2005 to February 2008. Subjects were diagnosed as ADHD based on the criteria set forth in the Diagnostic and Statistical Manual of Mental Disorders 4th edition, text revision version (DSM-IV-TR) and underwent neuropsychological tests including the continuous performance test (CPT). Treatment discontinuation was defined as the last prescription date when the medication possession rate (MPR) became less than 0.80. Subjects were divided into three groups and labeled as Group I, non-adherence without pharmacotherapy, Group II, non-adherence with short-term pharmacotherapy, and Group III, adherence with long-term pharmacotherapy. Results: Ninety (37.7%) patients were grouped as non-adherent (Groups I+II) and 149 (62.3%) as adherent (Group III). The adherence group exhibited lower intelligence, higher symptom severity, and a higher number of comorbid psychiatric disorders than controls. The use of stimulants was significantly associated with long-term adherence to treatment. Additionally, the duration of interval between the date of the first visit and the date of the first prescription was positively associated with long-term adherence. Conclusion: About two-thirds of patients diagnosed as ADHD adhered to the treatment six months after the first visit. With respect to patient evaluation and the development of treatment strategies, factors affecting early drop-out and longer follow-up must be considered.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.2
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• pp.49-55
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• 2011

The failure of electronic instruments is mostly caused by heat and shock. This shock causes the crack initiation at the solder joint interface of PCB component which is closely related with the formation of intermetallic compound(IMC). The Ag content in Pb-free Sn-xAg-0.5Cu solder alloy used in this study was 1.0, 1.2 and 3.0 wt.%, respectively. After soldering with PCB component, isothermal aging was performed to 1000 hrs. The growth of IMC layer was observed during isothermal aging. The drop impact property of solder joint was evaluated by impact bending test method. The solder joint made with the solder containing lower Ag content showed better impact bending property compared with that with higher Ag content. On the contrary to this result, the solder joint made with solder containing higher Ag content showed better impact bending property after aging. It should be caused by the formation of fine $Ag_3Sn$, which relieved the impact. It showed consequently the different effect of fine $Ag_3Sn$ and coarse $Cu_6Sn_5$ particles formed in the IMC layer on the impact bending property.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.452-457
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• 2005

Foam-type MFI zeolite catalyst was prepared by dispersing fine ($-0.2{\mu}m$) particles of MFI zeolite on silicalite foam. Catalytic cracking of n-octane was investigated over the foam-type catalyst and Delplot method was employed to interpret product compositions for deducing reaction mechanism. The Si/Al molar ratio of dispersed MFI zeolite was estimated 25 and its dispersed amount of silicalite foam was 25 wt％. Since the apparent density of the foam type catalyst was very low $0.11g{\cdot}cm^{-3}$, the catalyst loading amount could be varied from 0.02 g to 0.5 g without concerning pressure drop, providing a wide variance in the residence time of the reactants and products. The conversion and olefin yield in the catalytic cracking of n-octane increased with the catalyst loading. The product composition was very simple and could be explained by applying the protolytic cracking mechanism when the catalyst loading was small. Higher loading of the catalyst brought about further reactions of cracked products, accumulating lower olefin and paraffin with low reactivity in product stream and resulting in complex product composition.

• Korean Journal of Bronchoesophagology
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• v.15 no.2
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• pp.49-56
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• 2009

Purpose : To evaluate the treatment outcome for patients with locally advanced, unresectable esophageal cancer treated with relatively high dose radiation therapy(RT). Materials and Methods : From January 2000 to December 2008, 32 patients with locally advanced unresectable or medically inoperable esophageal cancer were treated with radiation therapy(RT) with or without concurrent chemotherapy. Ten patients were excluded from analysis because of distant metastasis and drop off. Patient distributions according to AJCC stages II, III IVa were 7(31.8%), 12(54.6%), 3(13.6%) respectively. The locations of tumor were cervical/upper thorax 3 (13.6%), mid thorax 13(59.1%), and lower thorax/abdominal 6(27.3%), respectively. Eleven patients received RT only, and 11 patients received cisplatin based concurrent chemoradiotherapy(CCRT). Median radiation dose was 65 Gy(range 57.6~72 Gy). Results : The median follow-up was 9.1 months(range 1.9~43.8 months). The response rates for complete response, Partial response, stable disease and Persistent disease were 6(27.3%), 11(50.0%), 4(18.2%) and 1(4.5%), respectively. Two patients(9.1%) suffered from esophageal stenosis and stents were inserted. Two patients(9.1%) had Grade 3 radiation pneumonitis and one of them expired due to acute respiratory distress syndrome(ARDS) at 36 days after completion of radiation therapy. The recurrence rate was 11(50.0%). The patterns of recurrence were persistent disease and local progression in 5(22.7%), local recurrence 3(13.7%) and concomitant local and distant recurrence in 3(13.7%). The overall survival(OS) rate was 32.1% at 2 years and 21.4% at 3 years(median 12.0 months). Disease free survival(DFS) rate was 17.3% at 2 and 3 years. All patients who had no dysphagia at diagnosis showed complete response after treatment and 100% OS at 3 years(p=0.0041). The OS for above 64.8 Gy group and 64.8 Gy or below group at 3 years were 60.6% and 9.1%(p=0.1341). The response to treatment was the only significant factor affecting OS(p=0.004). Conclusion : Relatively high dose radiation therapy in unresectable esophageal cancer tended to have a better outcome without increased complication rate. Further study with more patients is warranted to justify improved result.

• Journal of Digital Convergence
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• v.16 no.2
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• pp.57-64
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• 2018

The purpose of this study was to analyze the current status of life and psychological characteristics of 250 out of school youth in Cheonan city, and to identify the factors affecting the happiness. For statistical analysis, SPSS 21.0 were used, and reliability, mean comparison, correlation and multiple regression analysis were applied. First, adolescents who stopped studying due to family problems was lower in self-esteem than those who did for other reasons. Males was higher in happiness than females, and those who were less than two years of drop-out duration than those with over two years. Second, out of school youth used a day as 7.9 sleeping hours, 3.91 working hours. For the places for daily activities, they stayed at home for 10.73 hours, at working place for 3.66 hours. The future plan was the most for job plan. Third, there was a positive correlation between self-esteem, hope, and happiness of adolescents out of school. Fourth, the relative impact on the happiness of out of school youth ranked in the order of self-esteem, hope, employment plans, and household income level.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.2
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• pp.69-76
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• 2010

This paper proposed a new fast multi-reference frame motion estimation algorithm. The proposed algorithm reduces search areas of motion estimation using a linear relation of motion vector with distance of each reference frame. New algorithm executes full search area motion estimation in reference frame 0 and reference frame 1. After that, search areas in reference frame 2, reference frame 3 and reference frame 4 are minimized by distance of each reference frame and results of motion estimation in reference frame 0 and reference frame 1. The proposed algorithm does not use a threshold value which is obstacle of hardware implementation and processing time schedule. Also, it reduced computation quantity of multi-reference motion estimation. Hardware implementation of multi-reference frame motion estimation is possible by these features. Simulation results show that PSNR drop and bitrate increase of proposed algorithm are lower than those of previous fast multi-reference frame motion estimation algorithm The number of computation of new algorithm is reduced 52.5% and quality of result is negligible when compared with full search area motion estimation which has 5 reference frames.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.281-286
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• 2010

Effects of soaking period on physicochemical characteristics of chokong (black soybean picked in brown rice vinegar) and soaking solution were investigated. The pH and soluble solid contents in soaking solution increased rapidly whereas total acidity decreased during the first 4 days of soaking. The sudden drop of color 'L' and 'b' values in soaking solution occurred one day after start of soaking; in contrast, 'a' value increased by 1 day, and then decreased for soaking periods. The strength and hardness of chokong showed a decreasing trend as soaking for a long time, and the values of chokong were lower than those of control (black soybean soaked in water and freeze dried). The protein bands of chokong for soaking appeared only under 24,000 Da of molecular weight by electrophoresis. The content of total amino acids of chokong pickled for 7 days was 86.86 mg%, about 3 times for 28.36 mg% of raw black soybean. The contents of essential amino acids, especially, leucine and phenylalanine increased greatly in chokong. In vitro digestibility for protein was 62% in raw black soybean and 84% in chokong pickled for 7 days. Therefore, these results may assumed that chokong will be good source of amino acids.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.83-90
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• 2020

Plate heat exchangers(PHE) have been commercialized since the 1920s. Since then, although the basic concept of PHEs has changed little, its design and construction have progressed significantly to accommodate higher temperatures, higher pressures, and large heat exchanging capacities. The development trend of PHEs is consistent with heat plate developments with better thermal efficiency, lower pressure drop, and good flow distribution. The purpose of this paper is to introduce the main development processes of a plate cooler for medium-speed engine lubricant oil cooling in vessels which is in line with the development trend of PHEs and to provide its thermal performance data that were found out during experimental tests. The plate cooler in this study cannot measure the wall temperatures directly due to its structural characteristics, so the heat transfer coefficients were calculated using the modified Wilson Plot method. The water-to-water tests were first conducted experimentally to figure out the characteristics of heat transfer coefficients and pressure drops on the water side and then the water-to-oil tests followed to obtain the heat transfer coefficients on the oil side. The test results showed that heat transfer coefficients and pressure drops on both water and oil side increased with flow rates, and it was also found that all the development targets of the plate cooler in this study were achieved successfully.

• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.430-439
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• 2007

This study was carried out to(1) visualize the installation effect of an anti-wind net; (2) evaluate structural stability of typical anti-wind nets in Jeju; and (3) present the optimal specification of pipes in an anti-wind net for maximum instant wind velocities of 40 m/s and 45 m/s. The analyses were done for anti-wind nets with a mesh of 4 mm and a height of 3 m by using CFX and ANSYS. The results showed that the wind went down due to flow resistance when passing through an. anti-wind net. The anti-wind net with the supporting pipe being installed every two main columns was certainly unstable because the main column not sustained by the supporting pipe became cantilever. With regard to the position of a fixing point of the supporting pipe, von Mises stress on pipes was certainly increased as vertical positions of the supporting pipe were changed to be too lower or higher than an adequate position but there was little difference according to horizontal positions. The adequate vertical position was $2{\sim}2.5\;m$ high from the ground. For a maximum instant wind velocity of 40 m/s, the optimal specification of pipes was a main column of ${\varphi}48.1{\times}2.1$ t@2,000, cross beams(bottom and top) of ${\varphi}26.7{\times}1.9\;t$, cross beams(center) of ${\varphi}33.5{\times}2.1$ t/2ea and a supporting pipe of ${\varphi}31.8{\times}1.5$ t@2,000. In case of a maximum instant wind velocity of 45 m/s, the optimal specification of pipes with structural stability was a main column of ${\varphi}48.6{\times}3.25$ t@2,000, cross beams(bottom and top) of ${\varphi}26.7{\times}1.9\;t$, cross beams(center) of ${\varphi}48.1{\times}2.1$ t/2ea and a supporting pipe of ${\varphi}31.8{\times}1.5$ t@2,000.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.419-425
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• 1988

The clarified apple juice was pre-concentrated by reverse osmosis system as a trial for reduction of heat treating time and quality drop in concentration of the juice. The permeate fluxes through CA 865 and CA 960 membranes were higher than those of HR 95 and HR 98 membranes even at the low operating pressure. In the concentration limit depended on the membranes used, HR membranes operated at 60 bar showed $29.0^{\circ}$Brix, and the time required to reach the limit was 86 min for HR 95 and 71 min for HR 98. In cases of CA membranes run at 30 bar, the juice concentration was linearly increased without the limit, and longer time to reach the same concentration was required in comparison with HR membranes. As the juice concentration was increased, the loss of soluble solids was increased, and the average contents of soluble solids in the permeate passed through HR 95, HR 98, CA 865 and CA 960 were 1.3, 0.5, 7.5 and $2.3^{\circ}$ Brix, respectively, in the juice concentration range of 20.0 -$25.0^{\circ}$ Brix. The lower amounts of sugars, total acid and flavor volatiles were involved in the permeate through HR membranes, especially HR 98 than in the permeate through CA membranes.