Ultra - Soft Magnetic Properties in Nanocrystalline Fe81B₁₁Nb7Cu₁ Alloy

Heebok Lee,Kyeong-Jae Lee,Yong-Kook Kim,Sung-Ho Yoon,Taik-Kee Kim,Seong-Cho Yu 한국자기학회 2000 Journal of Magnetics Vol.5 No.3

The extremely soft magnetic behaviors in the nanocrystalline Fe_(81)B₁₁Nb_7Cu₁ alloy annealed at 450 ℃ and 550 ℃ for 1 hour in a vacuum were investigated by means of the magnetoimpedance (MI) effect and the incremental permeability. Because the MI effect can be obtained only in ultra-soft magnetic materials, the improvement of magnetic softness by proper thermal treatment was carefully monitored by the MI effect for all annealed samples. The changes of the incremental permeability as a function of an external field were also measured to verify the magnetic softness along with the MI measurement.

Magnetoimpedance Effect in Nanocrystalline Fe91.5-xZr7BxCu₁Al0.5 (x = 2, 4, 6, 8) Alloys

Heebok Lee,Yong-Kook Kim,Taik-Kee Kim,Chong-Oh Kim,Seong-Cho Yu 한국자기학회 2002 Journal of Magnetics Vol.7 No.1

The magnetoimpedance of Fe_(91.5-x)Zr_7B_xCu₁Al_(0.5) (x = 2, 4, 6, 8) alloys has been measured to investigate the influence of structural changes in the nanocrystallization process after thermal treatment. Annealing was performed at temperatures of 350℃, 450℃, and 550℃ for 1 hour in a vacuum. Ultra soft magnetic behavior was observed in the samples annealed at 550℃. The magnetoimpedance ratio and the longitudinal permeability ratio coincided with the softness of the magnetic properties of the thermally treated samples.

Temperature dependence of magnetoimpedance effect in amorphous CO?? Fe₄NiB?? Si? ribbon

Lee, Heebok,Cho, W.S,Kim, C.O,Kim, T.K,Kim, Y.K 公州大學校 基礎科學硏究所 1998 自然科學硏究 Vol.7 No.-

The temperature dependence of the magnetoimpedance (MI) effect is important both for scientific study and for thermal stability of MI sensors. We have performed the measurement of MI effect in amorphous Co66Fe4 NiB14Si15 (Metglas 2714A) ribbon from a cryogenic chamber where the temperature of the sample can vary from 10 to 300 K. The ac current was fixed at 10 mA for all measured frequencies ranging from 100 kHz to 10 MHz. The magncioimpedancc ratio (MIR) was revealed the drastic increment as a function of MIR(T)=MIR(O)exp(cT2), where c is a constant. The measured MIR values at room temperature are usually 2-3 times larger than the data measured at 10 K for all measured frequencies. However, the shapes of the MIR curves are remained. This result shows the potential application of the MI effect for a temperature sensor.

Super - giant Magneto - Impedance Effect of a LC - resonator Using a Glass - Coated Amorphous Microwire

Heebok Lee,Yong-Seok Kim,Seong-Cho Yu 한국자기학회 2002 Journal of Magnetics Vol.7 No.4

A new discovery of the super-giant magneto-impedance (SGMI) effect was found out in a LC-resonator consisted of a glass-coated amorphous Co_(83.2)B_(3.3)Si_(5.9)Mn_(7.6) microwire. The measurement was carried out at high frequency range from 100 ㎒ up to 1 ㎓ of an ac-current flowing along the wire and at varying axial dc-magnetic field in its range of ±120 Oe. The wires, about 16 ㎛ in diameter, were fabricated by a glass-coated melt spinning technique. The shape of the impedance curves plotted vs. a dc-field is changing dramatically with the frequency. The phase angle was also strongly dependent on this field. The external dc-magnetic field changes the circumferential permeability as well as the penetration depth, both in turn change the impedance of the sample. The drastic increments of SGMI at high frequency can be understood in terms of the LC-resonance phenomena. The sudden change of the phase angle, as large as 180°, evidenced the occurrence of the resonance at a given intensity of the external dc-field. The maximum ratio of SGMI reached in the experiment by precise tuning frequency equals 450,000% at the frequency of around 551.9075 ㎒.

광고 전문인력 양성을 위한 산관학 협력 방안

이희복(Lee, Heebok) 한국광고홍보학회 2014 광고연구 Vol.0 No.102

광고산업에서 인력이 차지하는 비중은 매우 크고 중요하다. 현업에서는 전문인력 부족이 심각한 반면, 대학에서는 예비 광고인을 충분히 배출하지 못하고 있다. 따라서 광고 전문인력 양성을 위한 산업, 학계, 정부 공동의 지원과 협력이 절실한 상황이다. 본 연구에서는 광고산업의 안정적인 발전이라는 측면에서 어떻게 하면 광고 전문인력을 양성해 나갈 수 있을 것인가에 초점을 맞추었다. 심층면접 분석 결과, 광고 전문인력 양성 일반, 광고 전문인력의 현황과 전망, 광고 전문인력 양성 방안, 산관학 협력방안 평가와 개선방안 4가지의 출현 주제를 발견하였다. 각 주제의 해결을 위해서는 관련 법안의 토대위에 추진 기관의 설립이 필요하다, 향후 업계, 학계, 정부의 지속가능한 협력으로 모두의 상생을 위한 광고 전문인력 양성과 광고산업 진흥이 가능하다는 시사점을 제안하였다. The portion of the workforces in advertising industry is very big and important. However, not to mention of the lack of expertise in the field, education for the pre-professional manpower in the university is urgently needed. Therefore, joint support and cooperation among Industry, academia, and government is necessary. This study focused on how to educate the advertising professional manpower to solve the stable development measures of the advertising industry. Through analysis of in-depth interviews, we found 4 main themes such as common Problems of advertising professional manpower, status and prospect of advertising professionals, advertising professional manpower education plan, evaluation and Improvement of industry-academia-government cooperation. To achieve the goals it is required the organization for propulsion on the basis of the relevant legislation. This study suggested the implication that both education for Advertising experts and advancement of advertising industry are possible with industry, academia sustainable cooperation in the future.

GMI Enhancement of Electroplated Permalloy Thin Films by an Additive

Hojun Lee,Wonbae Bang,Kimin Hong,Heebok Lee 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

전자게시대 도입과 옥외광고 중소사업자 지원방안

이희복(Lee, Heebok),차유철(Cha, Youcheol),이시훈(Lee, Si-Hoon) 한국광고홍보학회 2015 광고연구 Vol.0 No.106

시험 DFSS기법을 이용한 릴레이의 고장인자 영향도 분석

이희복(Heebok Lee),위신환(Shinhwan Wi),엄학용(Hakyong Eom),성기우(Kiwoo Sung),이용(Yong Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Failure factors of the automotive relay are operating voltage, load voltage, temperature and chattering count. In order to analyze effects of failure factors for the relay, effects of them are solved through DFSS method. In this study, the effect of failure factors is analyzed under the same load. The final results are as follows; ⅰ) Experiment is designed by L? tables of orthogonal arrays. ⅱ) failure factors of four types are used as control factors. And 3 levels are used. ⅲ) The influence of failure factors is interpreted in the following orders; (1. Chattering count 2. Load voltage. 3. Temperature. 4. Operating voltage.) ⅳ) finally for these reason, influence of failure factors is analyzed and verified.

비정질 Fe78Si9B₁₃ 합금의 구조와 자성 연구

이희복(Heebok Lee),송인명(In-Myoung Song),유성초(Seong-Cho Yu),임우영(Woo-Young Lim) 한국자기학회 1993 韓國磁氣學會誌 Vol.3 No.3

The X-ray diffraction pattern of amorphous Fe_(78)Si_9B₁₃ alloy was analyzed to obtain the radial distribution function (RDF) where the first peak was in the form of Gaussian function. The calculated coordination number of the form of Gaussian function. The calculated coordination number of the sample is 13.5, the mean distance between near-neighbor atoms r_0 is 2.595 Å. and a Gaussian parametet δr indicating near-neighbor atomic distribution is 0.27 Å. The temperature dependence of saturated magnetization at low temperature could be explained by spin wave excitations theory yielding the spin wave stiffness constant as 117.8 meVŲ. Also, we tried to fit the observed temperature dependence of saturated magnetization with the Handrich's equation of the modified molecular field theory for the amorphous ferromagnet. Nice fittings are obtained when we used the parameters △=0.32(S=1 / 2) and △=0,23(S=1), respectively. Finally, the calculated spin wave stiffness constant using the parameters and the structural data are 149 meVŲ for S=1 / 2 and 138 meVŲ for S=1, respectively. The mean exchange coupling integral between near-neighbor atoms was estimated to be 17.9 meV for S=1 / 2 and 6.7 meV for S=1.

정부광고 제도의 합리적인 운영방안: 전문가 초점집단면접을 중심으로

이희복 ( Heebok Lee ),홍문기 ( Moonki Hong ) 한국커뮤니케이션학회 2021 커뮤니케이션학연구 Vol.29 No.1

정부광고법 시행 2년이 지났다. 그러나 제도운영에 대한 평가, 업계에 미치는 영향에 대한 분석과 대응이 제대로 이루어지지 않고 있다는 지적이 제기되고 있다. 정부광고법 시행 이후 전문가 17명을 대상으로 의견을 청취한 본 연구의 분석결과, 정부광고 업무의 효율성과 투명성 제고의 필요성이 지적됐다. 정부광고는 정부라는 광고주가 국민의 세금을 재원으로 정책에 대한 지지와 참여를 목적으로 메시지를 전달한다. 이 때문에 정부광고법 시행에 대한 평가는 참여 주체의 이해관계에 따라 서로 다른 것으로 파악됐다. 정부광고법 도입으로 인한 순기능과 역기능을 고려해 향후 제도 개선방안 도출시 반영할 필요성이 있다. 본 연구의 제안이 정부광고의 효율적인 운영방안을 제시하고, 향후 광고산업 발전을 위해 활용되길 기대한다. Two years have passed since the implementation of the Government Advertising Act, but it has been criticized that the analysis and response to the impact on the industry have not been done properly. According to the FGI analysis of 17 Interviewee(Government Advertising Experts) since the enforcement of the Government Advertising Act, it is pointed out the improvement of the efficiency and transparency of government advertising work. Government advertisements convey the message that the advertiser, the government, aims to support and participate in policies with taxpayers’ money. For this reason, the current study found that the evaluation of the implementation regarding the Government Advertising Act is diverse relying on the interests of the their participating groups. Considering the net function and adverse function caused by the introduction of the Government Advertising Act, there is a need to reflect it in coming up with improvement measures in the future. It is expected that this study will provide efficient management measures for government advertising and be used for the public interest in developing the advertising industry.