• Resources Recycling
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• v.27 no.3
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• pp.8-15
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• 2018

Solvent extraction behavior of light rare earth elements (Pr, Nd) and medium rare erath elements (Tb, Dy) in the HCl-PC88A-kerosene extraction system was investigated in order to separate high-purity light rare earths (Pr, Nd) and medium rare earths (Tb, Dy) in the mixed rare earth chloride solution. In the batch test step, it was confirmed that the separation efficiency was good when the extractant concentration (PC88A) was 0.5 M, the equilibrium pH after extraction was 0.8 to 1.0 (initial pH 1.3 of the feed), the concentrations of hydrochloric acid in scrubbing solution was set as 0.1 M, the concentrations of hydrochloric acid in stripping solution was set as 2.0 M or more. Based on the experimental data obtained from the batch test, the mixer-settler was composed as follows; 4 stages of extraction, 8 stages of scrubbing, 4 stages of stripping, and 3 stages of pickling organic solution. The Mixer-settler was operated for 180 hours, and the operating conditions were continuously adjusted to obtain the high-purity light/medium rare earths. Finally, the purity of light (Pr, Nd) and medium rare earth elements (Tb, Dy) was reached as 3 N class.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.351-359
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• 1991

Demand for the rice of better eating quality is ever increasing in recent years. However. the rice is presently handled by the government and merchants as mixture of the rice of different varieties from the purchase of the rough rice to storing and milling. It is well known that the eating quality of rice varies significantly by variety. The present study aimed at evaluation of the effect of blending different rices on the change in palatability of low and high eating quality rices. The eating quality of a low quality japonica rice was improved significantly on sensory panel test by blending it with the Dongjin rice. one of the highest eating quality. only when the Dongjin was blended to 80 percent by weight. and also it was same for blending an ordinary quality rice of mixed varieties which has been stored by a governmental storehouse with a top class rice on free market. The eating quality of aged Tongil type rice. produce of 1987 and 1989 and a mixture of varieties, was improved significantly by blending it with a high quality glutinous rice on market to 20 per cent by weight. But Samgang rice. a high eating quality Tongil type variety. and an ordinary quality rice of Japonica varieties were not significantly improved by blending them with the glutinous rice by 20 per cent. Blending rices of the variety Nagdong. ordinary quality among varieties and low quality among Japonicas, Chucheong, a high quality rice among Japonicas. and Dongjin. one of the best eating quality rice among Japonicas, each other in different ratios did not affect significantly the sensory scores.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.75-84
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• 2016

This paper presents an investigation of the mechanical properties on non-sintered cement pastes immersed in sea waters at three different temperatures. The non-sintered cement pastes were synthesized using blended binder(Class F fly ash; FA and ground granulated blast furnace slag; GGBFS) and alkali activator(sodium hydroxide and sodium silicate). Binders were prepared by mixing the FA and GGBFS in different blend weight ratios of 6:4, 7:3 and 8:2. The alkali activators were used 5wt% of blended binder, respectively. Calcium carbonate was used as an chemical additive. The compressive strength, bulk density and absorption of alkali-activated FA-GGBFS blends pastes were measured at 3 and 28 days after immersed in sea waters at three different temperatures($5^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$). The XRD and SEM tests of the pastes were conducted at 28 days. Water-soluble chloride(free chloride) and acid-soluble chloride(total chloride) contents in the pastes were also measured after 28 days immersion in sea water. The experimental results showed that increasing the content of FA in alkali-activated FA-GGBFS blends pastes immersed in sea water increases the absorption, water-soluble chloride content and acid-soluble chloride content, and reduces the compressive strength and bulk density. And it was found that there was a variation of strength change for the alkali-activated FA-GGBFS blends pastes immersed in sea waters at three different temperatures that depends on the blending ratio of FA and GGBFS.

• Journal of Engineering Education Research
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• v.10 no.1
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• pp.60-76
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• 2007

In this study, the effect of a sustainable energy design project on academic achievement for engineering freshmen at Virginia Tech in fall semester 2006 in the United States was examined by experimental method. The department of engineering education at Virginia Tech was opened in 2004. In this experiment the population was approximately 1200 freshmen, and 5 classes were sampled. Subject name is engineering exploration, a theme of the instruction is sustainable energy design, the project was performed throughout a 6 weeks period with one by 50 minutes lecture conducted by faculty and one 90 minutes workshop conducted by GTAs (Graduate Teaching Assistants) every week. The statistical results using SPSS (ver. 15.0) are as follows: A paired-samples t test analysis was run on the pre- and posttest to determine academic achievement, the results indicated a significant increase in 4 classes of mixed gender at .05 significance level, but there was no significance at 1 group of female class. A paired-samples t test analysis was run on the pre- and posttest to get an attitude score, the results showed, the posttest scores decreased for 5 groups even though it was not statistically significant. Finally, in responses to an open-ended question about students' perceptions of their improvement in skills, the 3 most frequently identified skills were teamwork, design process, knowledge.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.5-13
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• 2008

In this study, It was carried out to evaluate the feasibility of recycled crushed concrete as aggregate used cement mortar replace sand and to investigate engineering properties of recycled aggregate for hazardous waste solidification. The compressive strength of cement mortar replaced 5-15% (wt.) recycled aggregate was over $163kgf/cm^2$ which is the standard of first grade concrete block class C. And cement mortar was examined to evaluate the stability by leaching test. Cu, Cd, Pb, Cr, and As as the heavy metals were proved very stable but mercury (Hg) was leached high concentration because it was simply tied to the cement surface. We investigated the crystal structures of cement mortar and they had shown the peaks of $Ca(OH)_2$, ettringite, and CSH (calcium silicate hydrate). As the result, the longer curing time, the higher CSH peak that means to increase compressive strength and the cement mortar was more stable. Therefore it was shown that it may be possible to apply hazardous waste solidification using recycled aggregate, fly ash and sewage sludge ash.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.620-627
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• 2005

The purposes of early orthodontic intervention are to correct obvious problems, to intercept developing problems and prevent them from becoming worse. Myofunctional influence on facial growth and the dentition change in muscle function and initiate morphologic variation in the normal configuration of the teeth and enhance an already existing malocclusion. Myofunctional therapy has been advocated since 1960's as the treatment for tongue thrust and other oral habits. Pre-orthodontic $TRAINER^{(R)}$ is introduced as functional device usable in children of mixed dentition to correct functional problems concerning soft tissue, tooth and skeleton. The most common cases to treat with Pre-orthodontic $TRAINER^{(R)}$ are lower anterior crowding, anterior open bite, Class II malocclusion and deep bite. Also, it can be used as correction of oral habits. Patients in this cases visited Department of Pediatric Dentistry, School of dentistry, Dankook University for orthodontic treatment. Pre-orthodontic treatment with Pre-orthodontic $TRAINER^{(R)}$ was carried out for correction of the oral habits.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.359-366
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• 2010

It was easy to find that children of a skeletal anterior crossbite in the early mixed dentition period showed a stark difference in the dental maturity between their maxillary and mandibular teeth, if they have stronger physical characteristics. If the difference of dental age between maxillary and mandibular teeth which can be identified via panoramic radiographs may serve as an early sign of class III malocclusion, this is considered valuable as a tool of early detection diagnosis. We obtained lateral cephalometric radiographs, panoramic radiographs, working model and clinical images of patients of Hellman dental age IIA and IIC who visited the department of pediatric dentistry, Pusan National University Dental Hospital and examined them to select 50 patents for normal occlusion group and skeletal anterior crossbite group, respectively. Their panoramic radiographs were used for the Demirjian's method to figure out dental ages of maxillary and mandibular teeth of each group and the eruption rate of the first molars. Their differences are as follows: 1. In both groups, the dental ages from Demirjian's method were advanced than the chronological ages. No sexual dimorphism was detected for the chronological or dental age in either group (p>0.05). 2. The difference of dental age of maxillary and mandibular teeth between the normal occlusion group and crossbite group was 0.22 and 0.69 years, respectively, with a higher difference in crossbite group(p<0.05). 3. Compared to the normal occlusion group, the crossbite group showed a higher difference in the eruption rate between maxillary and mandibular first molar(p<0.05).

• YAKHAK HOEJI
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• v.58 no.6
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• pp.397-404
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• 2014

The Ministry of Health and Welfare proposed the "undergraduate program specializing in pharmaceutical industry" in 2013, as part of its roadmap to assist domestic pharmaceutical companies to become the top-tier pharma companies in near future and provide skilled personnel tailored for pharmaceutical industry. However, it is not clear whether this "undergraduate program" meets the needs of pharmaceutical industry, especially when the number of pharmacy students increased from 1,200 to 1,700 per year since 2009. The purpose of this paper is to identify which educational background is preferred by pharmaceutical companies, by surveying the CEOs of domestic pharmaceutical companies and referring to recruitment advertisements shown in medical newspapers, specified by the fields within the companies. Two independent reviewers referred to recruitment session in Yakup newspaper and Dailypharm from May 2012 until January 2014, focusing on recruitments from pharmaceutical companies targeting bachelors' degree holders with no prior experience. 749 recruitments were observed during the study period, more than 90% of which were provided by domestic pharmaceutical companies, and regardless of the companies being domestic or multinational, pharmaceutical companies' preference for pharmacists was remarkable (44.3% for domestic and 65.8% for multinational), and the preference was especially high in the fields such as Medical, R&D, Market Access (regulatory affair/pricing and reimbursement), Business Development, and Marketing. Survey results showed that the need of establishing the undergraduate program specializing in pharmaceutical industry is mixed, suggesting that although there is need for the educating personnel targeting pharmaceutical industry, the undergraduate program would not be an answer due to current PEET system. Our study concludes that in the example of pharmaceutical companies' recruitments shown in medical newspapers, pharmaceutical companies prefer pharmacy major in almost all fields of the pharmaceutical companies, yet the pharmaceutical companies still perceive the gap between current bachelor's degree holders(including pharmacy majors) and the ideal personnel required for advancing to the "top-class" pharmaceutical companies.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.388-393
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• 2000

Cleft lip and palate is one of the most common congenital defects in oro-maxillo-facial region. Because most patients undergo surgical repair in early life, the sagittal jaw relationships used to be deteriorated gradually from palate surgery up to adulthood. Also, the maxillary lateral incisor may be absent or atypical-shaped in the cleft site and may not erupt or erupt ectopically, so multidisciplinary dental cares are needed for cleft lip and palate patients. The effects of the cleft lip and alveolus seem to be limited to that part of the dentofacial complex that surrounds the cleft area. In the maxillary arch, the anterior part of the non cleft segment has a tendency to be rotated forward. On the other hand, the cleft segment has a tendency to rotated slightly medially ; hence, the tendency for canines to be edge-to-edge and sometimes in crossbite. Lip and alveolus surgery adequetely correct these problems, with little untoward effect on the skeletal maxillary-mandible relationships. In this report, the patient has a repaired lip and cleft alveolus on the left side with congenital missing on '62, '22, oronasal fistula, and skeletal class III malocclusion which is not affected by lip surgery. Dental treatments for this patient including orthodontic(space supervision, functional regulator in mixed dentition, fixed therapy in permanent dentition) and prosthodontic(removable obturator with key and keyway attachment and Konus crown) therapy were performed to improve the patient's functions and esthetics.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.598-606
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• 1997

Among 136 patients having undergone mitral valve surgery from September of 1994 through August of 1995 in Sejong Heart Institute, forty four patients(18 males, 26 females) underwent mitral valve reconstruction using prosthetic rings and their clinical results were evaluated. Patients'ages ranged from 5 to 63 years(mean age 38.2 years). Mitral valvular diseases were due to rheumatic origin in 30 patients(68%), degenerative in 13(30%), and congenital in one patient(2%). Mitral regurgitation(MR) was in 33 patients(76%), mitral stenosis 2(5%), and mitral stenoinsufaciency 9 patients(19%). The patients were divided into Carpentier's functional groups : type I, 5 patients(11%) : type I, 24 patients(55%) ; type III, 4 patients (9%) i and mixed(II + III), 11 patients(25%). Average number of anatomic lesions of mitral valve per patient was 3.7. The techniques included prosthetic ring amluloplasty(44 patients, 32 Carpentier ring and 12 Duran ring), leaflet mobilization(24, 55%), chordae shortening(23, 52%), chordae transposition(23, 52%), commissurotomy(16, 35%), leaflet resection(9, 20%), papillary muscle splitting(8, 18%), and chordae reimplantation(1, 2%). Average 3.4 surgical procedures were applied on mitral valve per patient. There were two hospital mortality and one reoperation due to development of MR(grade III) after 2 weeks. During the mean follow up of 12 months, patients improved in terms of functional class of the New York Heart Association, which was mean 3.0 preoperatively and 1.3 postoperatively. Doppler echocardiographic studies showed adequate valve area(2.07$\pm$0.11 cm2 mean $\pm$standard error), improved ventricular contractiliy in 41 patients(93%), ab ence of MR in 23(53%), trace MR in 18(42%), and garde II MR in 2 patients(5%).