重크롬酸 稀薄溶液의 電解還元

金敎秀,安宰賢 嶺南大學校 工業技術硏究所 1988 연구보고 Vol.16 No.2

This study provides the optimum condition for the eleclrolytic reduction of dilute potassium dichromate solution. The materials used for electrodes were Pb, Ni, C, Fe and stainless steel. The reduction was very rapidly carried out by the use of the iron anode and cathode. The electrohemical reduction took place mainly on the cathode, and iron dissolved into the solution on the anode. In cathodic reduction, the rate of reduction was also higher, at higher current density and tempraure. The optimum conditions for cathodic current density, electrolysis temperature and time were found to be 3A/d㎡, 40℃, 8hrs respectively. Stainless steel electrode was the best as the cathode and opitimum distance between eleclrodes was 1.5cm.

二酸化鉛 電極의 製造

金栽撤,金敎秀 영남대학교 공업기술연구소 1984 연구보고 Vol.12 No.1

The lead dioxide electrode has been used as a substitute for the conventional platinum electrode in various electroxidation process, because it is cheaper than the latter and has high oxygen overvoltage comparable with that of platinum. However, as the nitric acid produced during the electrolysis exerts harmful effect on the lead dioxide electrode, it is neutralized by external circulation of the electrolytic solution of at the expense of cost, energy and time. For the purpose of improving the electrode, a given amount of Cu₂O, CuO, Cu(OH)₂, CuCo₃ㆍCu(OH)₂, PbO, or 2PbCO₃ㆍPb(OH)₂ all of which are insoluble in water but soluble in HNO₃, were added to the electrolytic solution of 20% Pb(NO₃)₂. The results of the electrolyses, such as weight, thickness, surface state, etc. as a function of PH, temperature, anodic current density and time, revealed that CuCO₃ㆍCu(OH)₂ was the optimal additive. In detail, a lead dioxide electrode having dense and smooth surface free of pinholes, cracks and warts was obtained at 4-6A/dm² and 50-70℃.

定電流 下에서 交流法에 依한 黃酸, 蓚酸 混酸浴 中에서 알루미늄板의 陽極酸化

金敎秀,金鍾旭 嶺南大學校 工業技術硏究所 1975 연구보고 Vol.3 No.1

In the process of anodic oxidation by the A.C. of aluminum plates in a H₂SO₄-H₂C₂O₄mixed acid bath, the properties of aluminum oxide film formed, the amount of Al dissolved and the coating ratio etc. were compared with those obtained in either simple H₂SO₄or H₂C₂O₄bath. Consequently, in the mixed bath, it was revealed that 1) thicker film of the oxide was formed than that formed in the H₂SO₄bath ; 2) the abrasion and corrosion resistance test result of the film formed were inferior to those formed in the H₂C₂O₄bath, but much superior th those formed in the H₂SO₄bath ; 3) the amount of Al dissolved was much smaller than that in the H₂SO₄bath, but a little greater than that in the H₂SO₄bath : 4) the coating ratio was the same as that in the H₂C₂O₄bath : 5) the dissolution of Al was inhibited than that in the H₂SO₄bath ; 6) in particular, the properties of the oxide formed at higher temperature was better compared to those formed in the H₂SO₄bath.

굴착 주변의 지반침하 예측

김교신,류제천,김송만,박춘수 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.2

Ground settlement and displacements of support structures due to deep excavation in urban area affect the stability of adjacent structures and retaining walls. Especially, the magnitude and distribution of ground settlements may directly give effects on the behavior of adjacent structures. So it comes to be important to judge precisely the effects on adjacent grounds and structures due to excavation. This can be achieved by means of ground settlements and differential settlements of structures, but present evaluating method on the ground settlement neglect the presence of adjacent structures. In this study, I have made Bowles and Bauer Method programs in order to find adjacent ground settlements. The results of program are like these. First, when you use measured horizontal displacement, the ratio of settlements of Bowles Method programs to Bauer is 0.86. Secondly, when you use measured horizontal displacement, settlements which Bowles Method program find is 5 times larger than settlements which Bauer Method program find when you use evaluated horizontal displacement.

交直流 倂用電解에 依한 銅粉의 製造

金敎秀,金光駱 嶺南大學校 工業技術硏究所 1982 연구보고 Vol.10 No.1

Many studies have been reported on the preparation of metallic powders. The methods in common use for the preparation are the pulverization of lump metals, the granularization of fused metals, the electrodeposition of the powders by DC, the reduction of metal oxides at high temperature, the dissociation of metals at gas phase, etc. The modification of the electrolytic process, among these method, was attempted here by applying AC in combination with DC. The effect of AC was examined by varying the current density ratio DC/AC in a mixed solution of 0.1M CuSO₄and 1.5M H₂SO₄at 30℃. In the case of preparing copper powder, both the stripped ratio of copper powder from the cathode and the current efficiency for the powder were better and the particles were finer when the current was applied in combination. The particle size, the flow rate, and the apparent density demanded for copper powder can be controlled by varying the current density ratio.

定電壓下 黃酸一蓚酸 混酸浴 中에서의 交流에 依한 알루미늄板의 陽極酸化

金敎秀,張學良 嶺南大學校 工業技術硏究所 1974 연구보고 Vol.2 No.1

混酸治 中에서 交流에 依한 20V 定電壓 下에서 알루미늄板을 陽極酸化시켜 生成한 酸化皮膜의 性質, 溶出한 Al量 및 coating ratio等을 液溫과 液의 濃度 變化에 따라 各 單獨浴을 使用하였을 경우를 相互 比較 檢討하였던 바 混酸治의 경우 50℃의 高溫에서도 黃酸 單獨浴의 경우보다 A1의 溶出量은 적고, 生成 酸化皮膜의 두께, 耐磨耗性 및 耐蝕性等 그 特性値는 좋았으며, 또한 修酸 單獨浴보다 耐磨耗性은 越等하게 좋으며, 酸化皮膜은 더 두껍게 生成되었다. The properties of aluminum oxide film formed, the amount of dissolved Al, etc. in the process of anodic oxidation of aluminum plate in H₂SO₄-H₂C₂O₄(4:1) mixed acid bath with the use of A.C. at constant voltage of 20V were compared with those obtained in either H₂SO₄or H₂C₂O₄simple acid bath under otherwise identical conditions. As a result, it was revealed, in the mixed acid bath, that 1) the amount of dissolved Al was smaller than that in H₂SO₄simple acid bath at various concentrations and temperature of the baths. It is indicative of the inhibiting effect H₂C₂O₄on the dissolution of Al: 2) the thickness, and abrasion and corrosion resistances of the film formed were thicker than and superior to those of the film obtain either in H₂SO₄or particularly in H₂C₂O₄simple acid bath: and 3) the film having the satisfactory characteristic properties was obtained even at high bath temperature of 50℃, and the decrease in the characteristic values of the film formed was gradual over 50℃. Thus, bath temperature can be easily controlled.

2단 튜브형 가열로 반응기에 의한 초미세 SiO₂입자의 제조 및 증착 연구

유수종,김교선 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

The effects of preheating the gas stream on deposition characteristics of ultrafine SiO₂particles were investigated theoretically. The model equation such as mass and energy balance equations and aerosol dynamic equations were solved to predict the particle growth and deposition. The gas temperatures, SiCl₄concentrations. SiO₂particle volumes, SiO₂particle sizes and deposition efficiencies of SiO₂ particles were calculated for various preheating temperatures. As the preheater setting temperature increases, the SiO₂particle size distribution becomes more uniform, because the effect of SiO₄diffusion decreases.

증착 구간에서의 온도 제어에 따른 SiO₂초미립자의 증착 특성 고찰

유수종,김교선 江原大學校 産業技術硏究所 1996 産業技術硏究 Vol.16 No.-

The deposition characteristics of ultrafine SiO? particles were investigated in a tube furnace reactor theoretically and experimentally controllin tube wall temperature in deposition zone. The model equastions such as mass and energy balance equations and aerosol dynamic equations inside reactor and deposition tube were solved to predict the particle growth and deposition. The particle size and deposition efficiencies of SiO? particles were calculated, changing the process conditions such as tube furmace setting temperature, total gas flow rate inlet SiCl? concentration and were compared with the experimental results.

대학생들의 흡연실태 조사

서수교,박재원,김성우 대구보건전문대학 2007 대구보건대학 論文集 Vol.27 No.-

This study was to survey for provide to institutional method about publicity of smoking dangerousness by 210 students of a college in Daegu city. As the result of this study, the gender smoking were significant difference between men(55%) and women(13%). A large majority(77%) in smoking group wanted to education of quit smoking. And starting age of smoking were a middle school(34%), a college(33%), a high school(25%), an elementary school(8%). Smoking amount per a day were less than a half(49%), less than a pack(35%), over than a pack(16%). The reason of continuous smoking were habituation(66%), to slove the stress(17%), to look smart(9%). So it is necessary to early education for quit smoking from elementary school. And a systematic program for college students must be established to solution the smoking at the government authorities, official quarters of school and citizens' groups, etc.

小白山 森林構造에 關한 硏究(Ⅰ) : 海拔高에 따른 泉洞溪谷의 植生構造를 中心으로

辛壽哲,金昌浩,朴敎秀 동국대학교 생명자원과학대학 연습림 1993 연습림논문집 Vol.- No.3

Cheon­Dong valley forest, bearing a cool­temperature, broadleaf­deciduous forest zone, ranging from 500m to 1200m by elevation in Mt. Sobeak National Park area was investigated for forest vegetation structure research. Ten plots of 1000㎡ size set up by the clumped sampling method and Classification and Polar Ordination were applied for vegetation structure analysis by environmental gradient the flora of the vascular plants collected from this investigated area were 32 families, 35 genera, 42 species and 3 varieties. Ranging from 500m to 1200m to elevation, Number of species, Number of individuals and Species diversity showed their highest values at 900m elevation respectively. And with increasing altitude those all values showed a tendency decreasing gradually. According to the Importance Value the leading dominant tree species in canopy layer were Styrax obassia, Quercus variabilis, Q. aliena, Carpinus codata while Lindera obtusiloba, Lespedeza bicolor were in understory at low elevation, ranging from 500m to 900m. Ant at high elevation area, ranging from 900m to 1200m, the leading dominant species were Q. monglica, Q. acutisima, Betula platyphylla var. japonica, Cornus controversa, Acer pseudo­sieboldianum, Fraxinus mandshurica, n canopy layer while Deuzia paviflora, Pinus laxiflora were in understory. The result from Classification and Polar Ordination analysis, they showed similarity that the forest vegetation of Sobeak valley area was classified into two sub­communities, one is Q. mongolica, Styrux obassia―Styrux obassia, Q. aliena, Carpinus codata―Styrux obassia, Lespedeza bicolor community and the other is Q. variabilia, Q. acutisima―Acer mono, Fruxinus rhynchophylla―Deutzia parviflora, Lindera obtusiloba community and the major environmental factors were considered to be the difference of altitude and the conditions of soil pH. The successional trends of tree species will be from Q. variabilis, Q. acutisima through Acer pseudo­sieboldianum, Fraxinus rhynchophylla to Carpinus codata at high elevation area, ranging from 900m to 1200m, and from Q. mongolica, Styrax obassia through Styrax obassia, Q aliena to Carpinus codata at low elevation area, ranging from 500m to 900m.