• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.269-277
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• 2017

Purpose: The aim of this study is to compare the performance of two piezoelectric engine systems by surveying satisfaction from dental clinicians. Materials and Methods: Two piezoelectric systems were evaluated: TRAUS XUS10 (Saeshin), PIEZOSURGERY touch (Mectron). For this study, 20 dentists responded to the 11 questionnaires in which 5 point Likert-type scale was used. The two devices were operated for 10 seconds and measured 5 times to compare the maximum noise values. In heat emission test, the handpiece was operated for 3 minutes and heat was measured at three positions each. Results: TRAUS XUS10 had higher satisfaction level on motor noise (P < 0.05). About function key and handpiece heat generation, PIEZOSURGERY touch showed higher satisfaction (P < 0.05) than TRAUS XUS10. The maximum noise level for each of the devices was confirmed to be 56.6 dB for the TRAUS XUS10 and 56.0 dB for PIEZOSURGERY touch. The two piezoelectric engines satisfied the safety standards with an operation temperature below $41^{\circ}C$ after having been operated for 3 minutes. Conclusion: Except for the function key and handpiece heat emission, TRAUS XUS10 has comparable performance with PIEZOSURGERY touch.

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.33-44
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• 2002

These studies were carried out to establish an effective in vivo embryo transfer methods in Hanwoo by analyzing several factors that influence this process. In an embryo transfer, recipients with grade A corpus luteum of the right ovary and that of grade B of the left one showed a higher pregnancy rate(p<0.1) than others. The pregnancy rates of frozen embryos were significantly lower(P<0.01) than those of fresh ones; the former resulting in 35% and the latter resulting in 56.2%. Transfer of embryos according to the estrus cycle(6.0 ∼ 9.0 days) did not show a significant difference in pregnancy rate with fresh embryos recording 45.4 ∼65.7% and frozen ones recording 22.0 ∼ 50.0%. According to the status of corpus luteum and embryo freezing or not, the pregnancy rate was higher on grade A corpus luteum with 40.8 ∼67.9% than B and C which ranged from 25.0∼56.0%. The results of embryo transfer according to the development stage and grade of embryos showed that regardless of the embryo's grade. transfer of morula recorded an average pregnancy rate of 46.3%. This results higher than the transfer of blastocyst which was 34.1%.

• Journal of Life Science
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• v.19 no.6
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• pp.720-727
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• 2009

Lyophilized powder (BP2FS) of soybeans fermented with Bacillus polyfermenticus KJS-2 (B. polyfermenticus KJS-2) exhibited in vitro antibacterial activities against eight pathogenic bacteria. BP2FS was used as a fodder additive for Oplegnathus fasciatus (0. fasciatus) culture. One group (UFD) of O. fasciatus was fed a commercial fodder, while another group (FD) was fed the same fodder, but including BP2FS ($6{\times}10^{4}$ cfu $g^{-1}$ fodder), two times daily for 120 days. The mean body weight of the FD group (67.29${\pm}$12.62 g) was higher than that of the UFD group (56.56${\pm}$8.21 g) after 120 days. The survival rate of FD was 80% compared to 40% for the UFD group. Cumulative mortalities in the FD and UFD groups were 18.95% and 60.98% respectively. B. polyfermenticus KJS-2 was isolated from the intestines of the FD group and the number of viable colonies was estimated to be $1.04{\times}10^{4}$ cfu $g^{-1}$. Iridovirus and Vibrio vulnificus was detected in the organs of the UFD group but not in the FD group. All of the infected fish showed typical clinical symptoms of hemorrhage in their tail fins. Dissection of the infected internal organs revealed liver congestion and spleen enlargement - typical symptoms caused by iridovirus infection. These results clearly show that BP2FS is highly beneficial in preventing O. fasciatus from iridovirus infection.

• The KIPS Transactions:PartB
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• v.18B no.5
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• pp.249-254
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• 2011

FGS (fine granularity scalability) supporting scalability in MPEG-4 Part 2 is a scalable video coding scheme that provides bit-rate adaptation to varying network bandwidth thereby achieving of its optimal video quality. In this paper, we proposed FGS coding scheme which performs one more bit-plane coding for residue signal occured in the enhancement-layer of the basic FGS coding scheme. The experiment evaluated in terms of video quality scalability of the proposed FGS coding scheme by comparing with FGS coding scheme of the MPEG-4 verification model (VM-FGS). The comparison was conducted by analysis of PSNR values of three tested video sequences. The results showed that when using rate control algorithm VM5+, the proposed FGS coding scheme obtained Y, U, V PSNR of 0.4 dB, 9.4 dB, 9 dB averagely higher and when using fixed QP value 17, obtained Y, U, V PSNR of 4.61 dB, 20.21 dB, 16.56 dB averagely higher than the existing VM-FGS. From results, we found that the proposed FGS coding scheme has higher video quality scalability to be able to achieve video quality from minimum to maximum than VM-FGS.

• Journal of Korean Neurosurgical Society
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• v.56 no.5
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• pp.390-394
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• 2014

Objective : In most patients with carpal tunnel syndrome (CTS), pain and/or paresthesia disappeared or decreased in a month after endoscopic carpal tunnel release (ECTR). However, subpopulation of patients showed delayed improvement following ECTR. We analyzed the delayed improvement hands to investigate the characteristics of those patients and to determine the predictable factors of delayed improvement. Methods : Single-portal ECTRs were performed in 1194 hands of 793 CTS patients from 2002 to 2011. Five-hundred seventy hands with minimal 1-year postoperative follow-up were included. We divided the 545 satisfied hands into early (group A) and delayed (group B) groups according to improvement period of 1 month. Demographic data, clinical severity and electrodiagnostic abnormality were compared between groups. Results : Group A included 510 hands and group B included 35 hands. In group B, 11 hands improved in 2 months, 15 hands in 3 months and 9 hands in 6 months, respectively. In group A/B, according to clinical severity, 60/1 hands were graded to I, 345/24 hands to II, 105/10 hands to III. In group A/B, based on electrodiagnostic abnormality, 57/3 hands were classified to mild, 221/11 hands to moderate and 222/21 hands to severe group. Statistical analysis between groups did not reach significance but electrodiagnostic or clinical severity had a tendency to affect the delayed response. Conclusion : It is difficult to predict the factors contributing to postoperatively-delayed response in subpopulation of CTS patients. However, we recommend that postoperative observation for at least 6 months is necessary in patients without symptomatic improvement.

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.1-8
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• 1991

The electronic and magnetic structure of Fe overlayers on W(110) is determined by means of the all-electron local spin density full potential linearized augmented plane wave (FLAPW) method with a single slab approach. Charge and spin densities, magnetic moments, contact hyperfine fields, and layer projected density of states (LDOS) are presented. For bilayer Fe coverage, we find magnetic moments to be 2.90 and 2.30 ${\mu}_B$ for the surface and subsurface Fe layers, respectively, corresponding to a 18% enhancement of the total magnetization compared with the calculated bulk value (2.22${\mu}_B$);For monolayer coverage the moment is 2.56 ${\mu}_B$ which is enhanced by 16% compared to bulk. Unusual changes in the magnetic hyperfine interaction are found in going from a monolayer to a bilayer coverage. Comparison of the results to the theoretical ones of the clean Fe(110) to discuss the hybridization and the negative pressure effects. We discuss our results by comparing them to experimental results.

• The Mathematical Education
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• v.56 no.1
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• pp.63-80
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• 2017

By analysing the examination papers from third grade high school students, we classified the errors occurred in the problem solving process of high school 'Geometry and Vectors' into several types. There are five main types - (A)Insufficient Content Knowledge, (B)Wrong Method, (C)Logical Invalidity, (D)Unskilled Expression and (E)Interference.. Type A and B lead to an incorrect answer, and type C and D cannot be distinguished by multiple-choice or closed answer questions. Some of these types are classified into subtypes - (B1)Incompletion, (B2)Omitted Condition, (B3)Incorrect Calculation, (C1)Non-reasoning, (C2)Insufficient Reasoning, (C3)Illogical Process, (D1)Arbitrary Symbol, (D2)Using a Character Without Explanation, (D3) Visual Dependence, (D4)Symbol Incorrectly Used, (D5)Ambiguous Expression. Based on the these types of errors, answers of each problem was analysed in detail, and proper ways to correct or prevent these errors were suggested case by case. When problems that were used in the periodical test were given again in descriptive forms, 67% of the students tried to answer, and 14% described flawlessly, despite that the percentage of correct answers were higher than 40% when given in multiple-choice form. 34% of the students who tried to answer have failed to have logical validity. 37% of the students who tried to answer didn't have enough skill to express. In lessons on curves of secondary degree, teachers should be aware of several issues. Students are easily confused between 'focus' and 'vertex', and between 'components of a vector' and 'coordinates of a point'. Students often use an undefined expression when mentioning a parallel translation. When using a character, students have to make sure to define it precisely, to prevent the students from making errors and to make them express in correct ways.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.3
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• pp.67-73
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• 1991

To define a small river in Korea. hydrologic- and geographic-characteristics. such as watershed area, channel slope, channel length and time of concentration are investigated and their limits are presented. The current equations of design-width-determination of the small rivers are examined and two equations for the design-width-determination of the small rivers have been suggested in this paper. A small river in Korea can be defined that watershed area is less than $10km^2$, channel length less than 6 km, channel slope over 0.02. time of concentration less than 30 minutes. As Band Q are defined as a design width and a design flood, respectively, the suggested equation to determine the design width is $B=1.235Q^{064}$ for less than $300m^3/sec$ of design flood. and when B and A are defined as a design width and a watershed area, respectively. the recommended equation is $B=8.794A^{0.56}$ for less than $10km^2$ of watershed area.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.98-102
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• 2005

The purpose of this study was to demonstrate biochemical properties of lactoferrin (Lf) obtained from the colostrum of Korea native cow. The molecular weight of the purified Korean native cow's Lf (K-Lf) was 81kDa, the isoelectric point was 9, and the content of iron was 0.56 mg/g, which is indicated that iron saturation of the lactoferrin was 40.6%. Amino acid composition and a-helix content were different K-Lf from bovine Lf (B-Lf). Immunological cross reactivity was observed between K-Lf and B-Lf but not between K-Lf and human Lf (H-Lf) by immunodiffusion test and Western blot analysis. Out results indicate that structure of K-Lf is different from that of B-Lf although K-Lf and B-Lf were immunologically cross-reactive.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.115-115
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• 2000

Wide band gap을 갖는 III-V족 반도체인 GaN는 파란색에서 자외선영역에 이르는 발광소자용으로, 그리고 최근에는 전자소자로도 가장 유망한 반도체 중의 하나이다. 하지만 격자상수가 일치하는 적당한 기판이 존재하지 않아 성장된 GaN 박막 내에는 많은 결함들이 존재하게 된다. 일반적으로 가장 널리 쓰이는 기판은 사파이어 기판이 주로 이용되고 있는데 사파이어는 GaN와 격자상수 불일치가 16%에 이르므로 고품질의 GaN 박막을 성장시키기 위해서는 격자상수 불일치를 어느 정도 완화시키면서 초기성장과정의 컨트롤이 매우 중요하다. 이러한 방법들로는 GaN박막 성장 전에 사파이어 기판 질화처리를 하거나 buffer 층을 도입하는 것인데, 이에 관한 많은 연구들이 보고되고 있다. 하지만 각각 두 공정에 관한 연구는 많이 되어 있지만 두 공정사이를 연결해 주는 공정처리법에 관한 연구는 보고되고 있지 않다. 따라서 본 연구에서는 사파이어기판 질화처리를 한 후 buffer 층을 성장시키기 전까지 chamer 내부의 분위기 가스가 GaN 박막성장 거동에 어떤 영향을 주는지에 관해 연구하였다. 질화처리 후 chamber 내부의 분위기 가스가 GaN 박막 성장 거동에 미치는 영향을 연구하기 위하여 두 개의 시편 A,B를 준비하였다. 시편 A는 먼저 사파이어 기판을 유기용매를 이용하여 cleaning 한 후 장비에 장입되었다. 수소분위기하에서 10nsrks 104$0^{\circ}C$에서 가열한 후 30초간 암모니아 유속을 900sccm으로 유지하며 사파이어 기판 질화처리를 수행하였다. GaN buffer 층을 성장하기 위하여 104$0^{\circ}C$에서 56$0^{\circ}C$로 온도를 내리는 과정중 질화처리를 위하여 흘려주었던 암모니아 유속을 차단한 채 수소분위기에서만 온도를 내렸다. 56$0^{\circ}C$에서 GaN buffer 층을 300 성장시킨 후 102$0^{\circ}C$의 고온에서 2$\mu\textrm{m}$ 두께로 GaN 박막을 성장하였다. 시편 B는 질화처리 후 단계부터 GaN 박막성장 단계에 이르기까지 AFM을 이용하여 두 시편의 성장거동을 비교 분석하였다. 두 시편의 표면을 관찰한 결과 시편 A는 2차원적 성장을 하며 매우 매끄러운 표면을 갖는데 반해, 시편 B는 3차원적 성장을 하며 매우 거친 표면을 보였다. 또한 두 시편 A, B를 XRD, PL, Hal 측정으로 분석한 결과 시편 A가 시편 B보다 우수한 구조적, 광학적, 전기적 특성을 보였다.