Cu-Zn-MG Ferrite의 자기적 특성에 미치는 소결온도의 영향

고재귀 崇實大學校 2000 論文集 Vol.30 No.1

The basic composition of Cu-Zn-Mg ferrite was CuxZnyMgz Feu0₄(x+y+z+u=1) Small amounts of additives such as 0.13 mol % NiO and 0.01 mol% CaC0₃were added to the basic composition of Cu-Zn-Mg ferrite. Specimens were sintered at different temperature at (1030℃, 1050℃, 1070℃) for 2.0 hours in air and followed by air cooling. The effect of the sintered temperature on the physical properties such as inductions, coercive forces, intial permeabilities, loss factors, curie emperature, etc. of Cu-Zn-Mg ferrite have been investigated. The physical properties obtained from the aforementioned Cu-Zn-Mg ferrite specimens are found out to be in 887 gauss for the residual induction, 2.0 oersted for the coercive force, 350 for the initial permeability, 75 for the Q value, etc. in this study. These physical properties indicate that the specimens can be utilized as the core of intermediated frequency transformer in the amplitude modulation, etc..

수평전단 철근으로 보강한 철근콘크리트 보의 전단거동

이재선,김대중,이용환,모귀석 대불대학교 2003 大佛大學校大學院 硏究論文集 Vol.2 No.1

In this study, 8 reinforced concrete(R/C) simple-span beams were tested statically up to failure to investigate the shear behavior of R/C beams with horizontal web reinforcements. Variables included two shear-span ratios(2.5 and 3) and the presence or absence of shear reinforcements. All beams without shear reinforcements and with horizontal web reinforcements failed in shear, and those with stirrups failed in flexure. In general, observed crack patterns agreed well with results from previous studies. The moet important finding was that the horizontal cracking is a primary phenomenon in the shear failure, and controls the overall behavior of the beam after initiating of the inclined shear crack.

마이크로 콘트롤러를 사용한 극배치 PID 자기동조기의 구성

하재해,추연규,임영도,최부귀 동아대학교 공과대학 부설 한국자원개발연구소 1993 硏究報告 Vol.17 No.2

In this paper, a speed controller using one-chip microcontroller is implemented and applied to a DC Servo Motor. Adaptive control is applied to a system for which a priori knowledge to its mathematical model is insufficient, on the basis of input and output data an apropriate controller is constructed through which the system input is synthesized. The pole-placement PID self tuning control algorithms as a control algorithm is used to research the performance of the controller through experiments.

Weinberg-Salam 모형에서 弱力子의 生成

고재걸,김귀년,김재원 경북대학교 교육대학원 1985 논문집 Vol.17 No.-

We caclulated the production and decay rates for the intermediate vector bosons (W,Z) in Winberg-Salam model. And we presented the differential cross sections for the processes e^+e^-→W^+W^-, e^+e^-→ZZ and e^+e^-→γZ in e^+e^-CM frame. Using these expressions we discussed the possibility of the event rate for the reactions.

입냄새 관련 인지도 조사

강은혜,강성귀,최재홍,성진효 조선대학교 구강생물학연구소 2003 Oral Biology Research (Oral Biol Res) Vol.27 No.1

The purpose of this study was to evaluate obtained information regarding a patient's halitosis and investigate about relationship between halitosis and related factors. Halitosis is general term used to describe any disagreeable odor in expired air. Also Halitosis affects a large proporation of population and may cause a significant social of psychological handicap to those suffering from it. Recently many scientist have concern about halitosis. The clinicians will be tried care to patient of halitosis more exactly, if he or she know patient's information about history, symptom, related factors of halitosis. The subjects were 77 who young peoples with 25 years old and using a questionnaire about self and other perception of halitosis, general and oral status, diet controls and cognition etc. The collected data was to analyzed and tested statistical significant. The results were as follows : 1.In presence of halitosis, the self perception was 26% and other Perception was 44%. 2.The group who was indicated malodorer by others is more sensitive in self-bad breath than other groups (p<0.05) 3.In life style, the other perception group have had more smoking than non-other perception group(p<0.05) . 4.The favorite food with strong smell have investigated kimchi , garlic, onion, coffee, spicy curry. Welsh onion and wine. 5. The kinds of food occurred to odor have investigated garlic, onion, coffee, kinds of kimchi, stew, meat and milk. 6. There was not significant correlation among other perception of halitosis and favorite food with strong smell, kinds of food occurred to odor, medical history, present health condition, food impaction to teeth, drinking habit and menstration.

테니스 選手들의 SERVICE SPEED 에 關한 硏究

金成泳,魯載貴 기전여자대학 1995 論文集 Vol.15 No.-

1. A winner is 6.45km/h faster than a loser in the first serice and there are no difference in second service of service speed between a winner and a loser. 2. A winner has 24.60% service score rate and a loser has 18.54% in each game Therefore a winner has a high service score rate for a loser. 3. A winner has 61.69% and a loser has 70.12% in the first service successful rate. So a loser is higher but service successful rate has a little influence on victory or defeat in a different result of service successful fate and speed. 4. A winner has 92.13% keep successful rate and a loser has 47.30% in a service game. Therefore a winner has a very high rate.

사료용 옥수수 연구 N. 조사료용 CNU 육성 교잡종 옥수수의 수량관련 주요특성

이희봉,정재영,김용일,박보영,지희정,문현귀 충남대학교 농업과학연구소 2006 농업과학연구 Vol.33 No.1

This study was carried out to compare a yield performance about CNU maize hybrids developed at the Maize Genetics and Breeding Lab, in Chungnam National University. Among the hybrids incorporated in the test, CNU 3 and 1 showed higher dry matter per 10a and lower kernel yield per 10a than check hybrid, Kwanganok. Hongchon 5 and Suwon169 showed higher kernel yield than Kwanganok. The average yield of CNU 3 hybrid in dry matter and CNU 4 in kernel yield were 2,106kg/10a and 854kg/10a in regional adaptability test, which were increased 33% and 8% compared with a check hybrid, respectively. Also, these hybrids had better stay green characteristics than check hybrid and showed moderately resistance to corn borer and leaf spot.

첨가제가 Mn-Zn 페라이트의 자기적 성질에 미치는 효과

이명호,김민경,고재귀,송승기 명지대학교 자연과학연구소 2004 자연과학논문집 Vol.23 No.-

우리 연구는 첨가제가 페라이트에 미치는 효과를 연구하기 위해 두 종류의 서로 다른 금속이온을 첨가제로 한 Mn-Zn 페라이트 시료를 제작하여 이들의 자기적 성질을 비교 분석하였다. 시료 제작에 사용된 Mn-Zn 페라이트의 주 원료 조성비는 31 mol% MnO, 16 mol% ZnO 그리고 53 mol% Fe_(2)O_(3)이다. 볼밀 작업을 통해 주 원료를 잘 혼합한 후 950℃에서 3시간 동안 하소하였다. 하소된 재료에 실험에 필요한 첨가물을 혼합한 뒤 성형과정을 거쳐 1300℃에서 3시간 동안 소결하였다. 첨가물은 0.1 wt% Na_(2)SiO_(3)만을 사용한 경우 (Sample 1)와 0.05 wt% Na_(2)SiO_(3), 0.1 wt% CaO와 0.05 wt% Al_(2)O_(3)를 첨가한 (Sample 2) 두 종류의 첨가제를 이용하였다. 두 시료에 대한 자성 특성을 측정한 결과 Sample 2 시료가 Sample 1에 비해 포화자속밀도(saturation flux density) B_(8)는 더 커진 반면 잔류자속밀도(residual flux density) B_(1)과 보자력(coercive force) H_(6)는 더 적어졌음을 확인하였다. 또한 고주파 측정에서도 0.05 wt% Na_(2)SiO_(3), 0.1 wt% CaO와 0.05 wt% Al_(2)O_(3)가 첨가된 시료에서 주파수 증가에 따르는 자기손실이, 다른 시료에 비해, 매우 완만하게 증가하는 것을 관찰하였다. 이들 자기 측정으로부터 0.05 wt% Na_(2)SiO_(3), 0.1 wt% CaO와 0.05 wt% Al_(2)O_(3)의 첨가제가 Mn-Zn 페라이트의 연자성 특성을 향상시켯음을 확인하였고, 이 결과는 이들 첨가물이 소결(sintering)과정에 관하여 Mn-Zn 페라이트 미세구조의 치밀화와 입자성장을 촉진시키는 효과가 있음을 보인다. We prepared two kinds of Mn-Zn ferrites composed of 31 mol% MnO, 16 mol% ZnO and 53 mol% Fe_(2)O_(3) as a main material. These were well mixed in a ball-milling machine and calcinated at 950℃ for 3 hours. After being mixed with two kinds of additives of 0.1 wt% Na_(2)SiO_(3) (Sample 1) and 0.05 wt% Na_(2)SiO_(3), 0.1 wt% CaO and 0.05 wt% Al_(2)O_(3) (Sample 2) respectively, the materials were molded and sintered at 1300℃ for 3 hours. The sample 2 was found to have more saturation flux density, and less residual flux density and coercive force than the other one, which means that the sample 2 is more suitable for soft-magnetic material. When the samples were applied by AC magnetic field in the frequency range of 10 kMz~1 MHz, both have shown relatively stable initial permeabilities up to 1 MHz. On the other hand, the loss factof of sample 2 became less than that of sample 1 in the high frequency range above 100 kHz although there was no much difference in the resistivity of both samples through the frequency change, which suggests the additives in the sample 2 has suppressed the viscosity loss in the high frequency range. We conclude that the 0.05 wt% Na_(2)SiO_(3), 0.1 wt% CaO and 0.05 wt% Al_(2)O_(3) additives has promoted coarsening and densification of the microstructure of the Mn-Zn ferrite and resulted in the better quality of the Mn-Zn ferrite

B_(2)O_(3)를 첨가한 Ni-Cu-Zn Ferrite의 자성에 대한 소결온도 효과

김민경,이명호,고재귀,송승기 명지대학교 자연과학연구소 2005 자연과학논문집 Vol.24 No.-

B_(2)O_(3)가 첨가된 Ni-Cu-Zn 페라이트의 소결온도 변화에 따른 자기적 성질을 연구하였다. 실험에 사용한 시료는 0.1 wt%의 B_(2)O_(3)를 (Ni_(0.204)Cu_(0.204)Zn_(0.612))Fe_(1.198)O_(2.98)에 첨가하여 각각 1000℃, 1100℃ 그리고 1200℃으로 4시간 동안 소결시켜 제작했다. 시료의 자기적 성질은 X-ray 회절 패턴, 자기이력 곡선, 초투자율, 손실계수 그리고 비저항을 측정하여 연구하였다. 자기이력 곡선과 초투자율 측정 결과로부터 세 시료 모두 우수한 연자성체가 되었음을 확인하였고, 소결온도가 높을수록 coercive force(H_(c))의 감소와 초투자율의 증가가 관찰되었다. 특히 가장 높은 온도(1200℃)로 소결한 시료의 Hc는 0.217Oe이었고, 초투자율은 전 영역의 주파수에 걸쳐 가장 큰 값을 유지하였다. 전력손실은 1 ㎑~10 ㎒ 주파수 영역의 교류에 대해 시료 모두 안정된 값을 갖고, 1200℃로 소결된 시료의 전력손실과 비저항은 시료 중 가장 적은 값을 가졌다. We have studied the dependence of B-doped Ni-Cu-Zn ferrite on sintering temperature. The samples were prepared from 0.1 wt% B_(2)O_(3)-doped (Ni_(0.204)Cu_(0.204)Zn_(0.612))Fe_(1.198)O_(2.98) ferrites and sintered at 1000℃, 1100℃ and 1200℃ for 4 hours respectively. The crystal structures of the samples were identified by X-ray diffraction pattern, and the magnetic properties of those were investigated by measuring X-ray diffraction pattern, hysteresis curve, initial permeability and resistivity. The results showed that all of the three samples were good soft magnetic materials, and initial permeability increased with the decreasing of Hc as the sintering temperature became higher. Especially, the sample sintered at 1200℃ showed Hc of 0.217Oe and maintained the highest value of initial permeability through the whole frequency range. The loss factors of the samples showed good frequency stability from 1 ㎑ to 10 ㎒ and both the loss factor and resistivity of the ssample sintered at 1200℃ was the least.

Carbon tetrachloride를 투여한 rat의 hepatic lipid 축적에 미치는 vitamin E의 효과에 관한 연구

박은주,이경연,이미영,이외숙,장재정,정귀은,최진희 曉星女子大學校 藥學大學 學生會 1988 曉星藥誌 Vol.4 No.-

The present studies were undertaken to evaluate the effect of vitamin E, CCl_4 on the change of hepatic triglyceride, hepatic cholesterol, hepatic phospholipid in male rat. The result obtained from this study were summarised as follows: 1. Hepatic phospholipid of CCl_4 treated rat was increased in proportion to CCl_4 dosage but after concomitant injection(I.P) of vitamin E and CCl_4, hepatic phospholipid was significantly decreased in comparison to that of CCl_4 alone injection. 2. There was no effect on hepatic cholesterol concentration either CCl_4 alone injection(I.P) or concomitant injecton(I.P) of vitamin E and CCl_4. 3. Hepatic triglyceride of CCl_4-treated rat was significantly increased in comparison to that of normal rat but hepatic triglyceride of rat concomitant injection of vitamin E and CCl_4 was significantly decreased in comparison to that of CCl_4 alone injection.