중력에 의한 경상분지 남부의 지각구조에 대한 연구

최광선,이준동,김광호,허남철 부산대학교 기초과학연구소 1988 부산대학교 기초과학연구소 연구논문집 Vol.8 No.-

The gravity anomaly of the southern part of the Gyeongsang basin and the adjacent sea is analyzed. According to the power spectum analysis method. calculated the mean depth of the moho and the boundary between the sedimentary layer and the basements is 32km and 6km respectively. With these values, regional and residual anomalies of the gravity for each depth are calculated by the running average method and interpreted. By the sin X/X method, the crustal thickness and the depth of the boundary of the sedimentary layer in the southern part of the Gyeongsang basin turns out to vary from 34km to 28km and from 8.5km to 0.5km repectively.

貝類中 아미노산의 吸光度 定量에 關한 硏究

崔七男 朝鮮大學校 師範大學 1976 師大論文集 Vol.7 No.-

This paper is an attempt to discuss an analysis of a simple and rapid spectrophotometric method without particular apparatus or difficult procedures. Sample which was hydrolysed in the presense of 6N-hydrochloric acid for 26 hours at 80℃ showed good reproducibility of amino acid analysis. This experiment also showed the best spectrophotometric determination 610 nm from pH 3.5 to 4.5.

알루미늄의 전기분해를 이용한 인 제거

정경훈,최형일,정오진,최칠남,정재경 한국환경과학회 2000 한국환경과학회지 Vol.9 No.1

Laboratory experiments were performed to investigate the effects of various factors on the phosphorus removal by electrolysis with aluminium electrodes. The efficiency of phosphorus removal increased with increasing of voltage applied, surface area of electrodes and electrolyte concentration, and decreasing of electrode distance. The phosphorus removal was not affected by the connection number of an electric circuit. The amount of aluminium ion eluted from electrodes according to Faraday's law was 4.47 ㎎ and the Al/P mole ratio was 2.14 at the electric current value of 20 ㎃.

생체용 Ti합금의 양극분극특성에 미치는 Zr 및 Pd의 영향

정종현,이길홍,최칠남,노학,백승남,이상열 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.2

The corrosion resistance of Ti-Zr-Pd-Cr alloys were investigated in order to reveal their possible use for new biomedical implant materials. Titanium alloys consisting of 10∼20%Zr, 0.0∼0.4%Pd and 0.15%Cr were prepared by vacuum arc-melting as alloying elements instead of using hardness Al and V in response to recent concerns about the long term safety of Ti-6%Al-4%V ELI alloys. The Ti-Zr-Pd-Cr alloys were heat-treated at 1000℃ for 2hrs under a vacuum atmosphere. The effect of Zr and Pd Ti alloys on the corrosion resistance for biomedical implant was investigating the anodic polarization curve at 37℃ in 5%HCI solution deaerated by high-purity N₂gas bubbling. The critical current density for passivation(I ) of Ti-Zr-Pd-Cr alloys didn't reveal markedly. Passive current density(I ) at 1.0V vs. SCE of this alloys decreased with increasing Zr in the contents from 10 to 20% and decreased with containing Pd in the range from 0.2 to 0.4%. Potential(E ) at 0.1A * m-² of this alloys increased with increasing Zr in the contents from 10 to 20% and increased with containing Pd in the range from 0.2 to 0.4%. For the Co-30%Cr-6%Mo alloy, passivity zone is narrow, and rapid increase of current density result from the low potential in comparison with Ti and Ti alloys. The corrosion resistance by the anodic polarization of Ti-20%Zr-0.2%Pd-0.15%Cr alloy was found to be superior to those of the Ti, Ti-6%Al-4%V alloy and Co-30%Cr-6%Mo alloy. The passive films formed on the Ti-20%Zr-0.2%Pd-0.15%Cr and Ti-6%Al-4%V alloys in the anodic polarization test consist mainly of TiO₂, Ti compound, ZrO₂, Al₂O₃and V₂O₃.

Chemical Properties of Co(II) Compound Containing Endocrine Disruptor, Bis-Phenol A

Choi, Chil-Nam 한국환경과학회 2002 한국환경과학회지 Vol.11 No.2

The chemical behavior and properties on the redox state of environmental pollutant has been investigated by electrochemical methods. We carried out to measure the variations in the redox reaction of differential pulse polarogram and cyclic voltammogram. The results observed the influences on redox potential and current of various factors with temperature and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from qusi-reversible to irreversible processes. Also, it was mixing with reaction current controlled. The bis-phenol A in the waste water was made to compound with cobalt ion and it take away from the separation into compound. The Co(BPA)_2 compound was not found to be dissociation in waste water. However, this compound is a very unstable(K=1.02) and for a while, it was to be a dissociation. Therefore, we believed that it was likely to a toxic substance.

Affecting of Corrosion Potential and Current Density on Variation Polarization Curves with Polyvinylchloride (I)

Choi, Chil-Nam,Yang, Hyo-Kyung,Jung, Oh-Jin The Korean Environmental Sciences Society 1998 Environmental sciences Vol.2 No.2

In this study, we carried out the experiments for measuring the variations of corrosion potential and current density for polarization curves with polyvinylchloride. The results exhibited especially the influence affecting the corrosion potential and various conditions (temperature, day, pH, bacteria, and added salt). The second anodic current density peak and the minimum passive current density are designated $I_P/I_0,$ respectively. The value of $I_P/I_O$ is used as a measurement for the extent of degradation of the polyvinylchloride. The potentiodpnamics parameters of the corrosion were obtained using Tafel equation.

Electrochemical Behavior of Polymers in Aprotic Medium

Choi, Chil-Nam,Yang, Hyo-Kyung,Kim, Il-Do,Baek, Seung-Nam,Son, Hyo-Youl 조선대학교 기초과학연구소 2001 自然科學硏究 Vol.24 No.-

In this study, we carried out the electrochemical experiments for measuring the variations of oxidation potential and current density for polarization curves of poly(vinylchloride) and poly(carbonate). The results were examined to find out especially the factors affecting the corrosion potential under various conditions such as temperature, pH, enzyme, and salts added. The lines representing an active anodic dissolution were shifted only slightly in the 'noble' potential direction depending on temperature, pH, enzyme, and salt. The Tafel slope for anodic dissolution could be determined because of polarization effect depending on conditions. On the other hand, the line slopes of the polarization curves were shifted noticeably in the noble direction. The susceptibility were obtained to the current density ratio (I_(t)/I_(f)) with a maximum current density (forward and reverse scan). The value of I_(t)/I_(f) was used in measuring the extent of corrosion sensitivity of the poly(vinylchloride) and poly(carbonate). The potentiodynamics parameters of the corrosion were obtained using a Tafel plot. The transfer coefficient α can be evaluated from the anodic slope(1-α)nF/2.3RT and the electrode reaction is a irreversible under all conditions.

Oxidation of Polycarbonate and Polypropylene in Organic Solvent

Choi, Chil-Nam,Kim, Il-Do,Yang, Hyo-Kyung,Kim, Moyung-sun,Baek, Seurg-Nam,son, Hyo-Youl 조선대학교 기초과학연구소 2001 自然科學硏究 Vol.24 No.-

We carried out to measure the variations in the corrosion potential and current density on polarization curves of the polycarbonate and polypropylene. The results were particularly examined to identify the influences on corrosion and corrosion rate of various factors including temperature, pH, salt, and oxygen. The Tafel slope for the anodic dissolution was determined by the polarization effect depending on these conditions. the optimum conditions were established for each case. The second anodic current density peak and maximum passive current density were designated as the relative corrosion sensitivity (I_(t)/I_(f)). The mass transfer coefficient value(α) waw determined with the Tafel slope for anodic dissolution based on the polarization effect with optimum conditions.

Comparison of chemical properties of Co(II) and Cu(II) Compounds with Bis-Phenol A(Endocrine Disruptor)

Choi, Chil Nam 한국환경과학회 2002 한국환경과학회지 Vol.11 No.5

The chemical behavior and properties of the redox state of environmental pollutants were investigated using electrochemical methods. Cyclic voltammograms were performed on the compounds to measure the variations in the redox reactions. Temperature and pH were established as influencing the redox potential and current. The electrode reactions were a mixture of quasi-reversible and irreversible processes, which changed according to the reaction current. Although the Co(BPA)_2 and Cu(BPA)_2 compounds were not found to dissociate in wastewater, they were very unstable(K=1.02).

Influence of Corrosion Potential and Current Dentity on Variation Polarization Curves with Polyvinylchloride

Choi, Chil-Nam,Yang, Hyo-Kyung,Kim, Sun-Kyu 조선대학교 기초과학연구소 1999 自然科學硏究 Vol.22 No.1

In this study, we were carried out the experiments for measuring the variations of corrosion potential and current density for polarization curves with polyvinylchloride. The results were examined to find out especially the influence affecting the corrosion potential and vary condition (temperature, pH, enzyme, and added salt). The lines representing active anodic dissolution were shift only slightly in the noble potential direction by temperature, pH, enzyme and salt. Tafel slope for anodic dissolution could be determined because of polarization effect to vary condition. Line slope of the polarization curves describing the active-to-passive transition region was shifted noticeably in the noble direction. Also, from the variation of conditions, we are speculated a best of conditions which it most readily transforms (temperature, pH, corrosion rate, and resistance of corrosion potential). The second anodic current density peak and maximum passive current density are designated degradation(I_p/I_0). The value of I_p/I_0 is used in measuring for the extent of degradation of the polyvinychloride. The petentiodynamics parameter of the corrosion was obtained using Tafel plot.