무선통신시장개방 및 발전계획

이정행 정보통신정책연구원 1989 세미나및공청회 Vol.1989 No.

특집-'92년도 통신기기산업의 전망과 대응

이정행,Lee, Jeong-Haeng 한국전자정보통신산업진흥회 1992 電子振興 Vol.12 No.1

忠淸南道地方의 作付體系 變遷에 關한 硏究

李正行,具千書,蔡濟天 단국대학교 1984 論文集 Vol.18 No.-

This work was carried out to investigate the changes in cropping systems and the factors influencing it during past 20 years from 1960 to 1980 at central Korea. 12 villages were selected as sample location based on the analysis of agricultural census, then the on-the-spot survey was carried out. The results were summarized as follows; 1. The barley in double paddy was planted over 50 percent of the paddy field at 1960's, on the other hand, it was decreased below 10 percent at 1980's. 2. The simple cropping system of barley-legume formed 70∼80 percent of total upland area at 1960's, but the various cropping patterns including such cash crops as vegetables and industrial crops were developed at 1980's. 3. The major factors influencing the change of cropping system were earnings, natural conditions of location and rural extension, whereas, the minor factors were release of new variety, cultural technique, markets, labor power and activities of farm leaders. 4. It was considered that the cropping system was influenced greatly by the natural conditions such as climate and soil conditions in case of the same technical, economical and social circumstances.

급성음낭증에서 고환수 염전의 임상적 의의

이정행,윤상민,박원희 大韓泌尿器科學會 1996 Korean Journal of Urology Vol.37 No.2

學校敎育에 있어서 人間主義敎育의 受容과 限界

이정행 광주대학교 1998 社會科學硏究 Vol.8 No.-

I have surveyed on the basic of human educational theory and the educational process on the basic of chiefly human psychology, together with the historical background of human education and have arranged the interests on the limitation and alternative plans of this theory. There are liberalism and enlightening property of the naturalism in the theoritial basic of human educational theory, and there consist in the reconstruction of humanism through the psychological process of human and somewhat romantic expectation of the consttuction of ideal society. We can understand that aftering dealing with the human property which has not been disclosed yet, and we are to recognize them as the potentiality and growing power, but we should not neglect that they are eager to change the source of problems into the inner of human. We should discard the first stage recognition of the human property as the simple purity, and the relation between society and culture. We have to consider the meaningful system of the principal as the dynamic and the voluntary one. We are to overcom the environment, the system, and the sense of value which has been acting as the challenging powers and all kinds of meanes of the human, and we need to develop the new program for the cognitive power to make and conduct all the conditions of reality which are to realize the human value and to educate the human of the sense of value and the bravery. Thus, the conception of the experience or the elaboration which is considered on the principal self-voluntary situation of the learner by J. Dewey or G. Kerschensteiner has many suggestions for us.

신세포암세포주의 성장에 대한 온열요법의 효과

이정행,이은식,박원희 大韓泌尿器科學會 1998 Korean Journal of Urology Vol.39 No.4

磻溪 柳馨遠의 敎育思想 : 學校事目을 中心으로

이정행 광주대학교 1997 社會科學硏究 Vol.7 No.-

忠淸南道地方의 栽培作物 變遷에 關한 硏究

李正行,蔡濟天,具千書 단국대학교 1984 論文集 Vol.18 No.-

This work was conducted to investigate the changes in cultivated crops during past 20years in central region of Korea. The results were summarized as follows; In 1960's, 91∼92% of arable land was planted for cereal food crops, 4.5∼5.5% for vegetables and 2.4∼4.3% for potatoes, respectively. In 1980's, however, the acreage of cereal food crops was decreased dramatically, on the contrally, the acreage of vegetables and industrial crops were increased considerably. The acreage of barley, wheat, millet, soybean, azuki bean and sweet potato were reduced greatly, whereas rice was increased everywhere, and such cash crops as white potato, sesame, tobacco, vegetables and fruit trees were increased at most of the area during past 20years.

샌드블라스팅과 프라이머가 지르코니아와 레진시멘트의 전단결합강도에 미치는 영향

이정행,김형섭,배아란,우이형,Lee, Jung-Haeng,Kim, Hyeong-Seob,Pae, Ah-Ran,Woo, Yi-Hyung 대한치과보철학회 2011 대한치과보철학회지 Vol.49 No.1

Purpose: The aim of this study was to evaluate the effect of mechanical, chemical surface treatments on the zirconia-to-resin cement shear bond strength (SBS). Materials and methods: Eighty zirconia discs (Lava, 3M ESPE) and eighty zirconia/alumina composite (Zirace, Acucera) were embedded in an epoxy resin base. Zirconia discs were randomly divided in to four treatment groups(10 for each manufacturer): $50\;{\mu}m$ $Al_2O_3$ sandblasting (S50), $110\;{\mu}m$ $Al_2O_3$ sandblasting (S110), $50\;{\mu}m$ $Al_2O_3$ and primer (Z-Prime Plus, Bisco Inc) (S50z) and $110\;{\mu}m$ $Al_2O_3$ and primer (Z-Prime Plus) (S110z). Two resin-based luting cements (Calibra, Panavia F) were used to build 2 mm diameter cylinders onto the zirconia. After 24 h of storage in water, SBS testing was evaluate using a universal testing machine. Bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and post hoc comparison was done using Tukey test (${\alpha}$ = .05). Results: Groups using primer showed the high shear bond strength. The groups that did not use primer presented lower shear bond strengths. Conclusion: The use of primer (Z-Prime Plus, Bisco) had significantly higher shear bond strengths. 연구 목적: 최근 지르코니아가 전부도재관의 코어로 많이 사용되고 있다. 지르코니아와 레진 시멘트의 결합 강도를 높이기 위한 기계적, 화학적인 표면 처리 방법들이 연구되고 있다. 이 연구에서 여러 표면 처리 방법에 따른 지르코니아와 레진 시멘트의 전단결합강도를 알아보고자 한다. 연구 재료 및 방법: 80개의 지르코니아 (Lava, 3M ESPE, St. Paul, MN, USA) 시편과 80개의 지르코니아/알루미나 복합체 (Zirace, Acucera Co Inc, Korea) 시편을 디스크형태로 제작하여 에폭시레진에 매립하였다. 이들을 각각 4개의 군으로 나누어 $50\;{\mu}m$ $Al_2O_3$ sandblasting, $110\;{\mu}m$ $Al_2O_3$ sandblasting, $50\;{\mu}m$ $Al_2O_3$ sandblasting과 프라이머 (Z-PRIME Plus, Bisco Inc, Schaumburg, IL, USA) 사용, $110\;{\mu}m$ $Al_2O_3$ sandblasting과 프라이머 (Z-PRIME Plus) 사용 군으로 나누었다. 표면 처리한 지르코니아 표면에 2가지 레진 시멘 (Calibra, Panavia F)으로 접착하였다. 그 후 증류수 ($37^{\circ}C$)에 24시간 보관 후 전단 결합 강도 실험을 시행하였고, SEM을 사용하여 표면 처리한 표면과 전단강도 실험 후 파절양상을 관찰하였다. 결과: ANOVA분석에 따르면, 두 가지 종류의 시편 모두에서, 프라이머 (Z-PRIME Plus)를 사용하여 표면 처리한 군들이 전단 결합 강도가 높았다 (P < .05). 결론: 기계적 결합 강도와 함께 새로운 프라이머를 사용하는 것이 지르코니아와 레진 시멘트의 접착 강도를 증가시킨다.

Calculation of molecular weight distribution using extended Cole-Cole model and quadratic mixing rule

이정행,김상모,조광수 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.1

We suggest a numerical method to calculate molecular weight distribution from linear viscoelastic data. The calculation method consists of three components: (1) a viscoelastic model of a monodisperse polymer as a function of molecular weight; (2) the mixing rule connecting viscoelastic data of monodisperse and polydisperse polymers through molecular weight distribution; (3) an algorithm which calculates the molecular weight distribution from the chosen mixing rule. Since we cannot measure the relaxation modulus of all monodisperse samples, we need an accurate monodisperse model for any molecular weight. It is known that a dynamic test is more reliable than a relaxation test, while the mixing rule needs relaxation modulus. Hence, we should have a smart numerical method that can convert dynamic data to relaxation modulus with the minimum conversion error. If we use the numerical method, then we have to generate numerical data from the model. Then it takes quite a long time. On the other hand, if we have a monodisperse model with the analytical relaxation spectrum, then calculation time can be reduced dramatically. Since the conversion from relaxation modulus to dynamic modulus suffers from smaller errors than the reverse conversion because of ill-posedness of the interconversion, the analytical conversion can be implemented more quickly at an acceptable level of errors. This paper proposes a new method satisfying the requirements.