세장판요소를 갖는 스테인리스강 각형강관 압축재의 좌굴내력에 관한 실험적 연구

강현식,김태수 한국강구조학회 2023 韓國鋼構造學會 論文集 Vol.35 No.6

In this study, experiments of austenitic stainless steel (STS304 TKC) SHS(square hollow section) compression member under concentric axial loading were conducted to investigate buckling strength. Specimens are composed of slender section with large width-to-thickness ratio and same plate thickness. Main parameters are column length and width. Most of specimens except one with 50 mm width and 2,000 mm length and global buckling failed by local buckling. Yield strength obtained from compressive material tests of stub column got lower by 34 % than that of tensile coupon test results. The test buckling strengths were compared with those predicted by current stainless steel design specifications (American Society of Civil Engineers [ASCE] and Eurocode [EC3]) for stainless steel compressive members, American Iron and Steel Institute (AISI) code for carbon steel. It is known that design strengths with tensile material test data were close to test buckling strengths. 이 연구에서는 오스테나이트계 스테인리스강 각형강관(STS304 TKC) 압축재의 좌굴내력을 조사하기 위해 중심압축력실험을 수행하였다. 2종의 각형강관의 폭두께가 큰 세장판 요소 단면으로 구성되며 실험체의 주요 변수는 각형강관의 폭과 길이이다. 최대내력 시점에서 전체좌굴이 발생한 폭이 50 mm이고 길이가 2,000 mm인 실험체를 제외하고는 모두 국부좌굴이 발생하였다. 세장판 요소로 구성된 각형강관 압축재로 단주 실험체에서 조기에 국부좌굴이 발생하여 압축재료항복강도가 인장 재료항복강도보다34 % 낮아 기준좌굴내력이 과소평가되었다, 냉간성형 스테인리스강에 대한 유럽기준(EC3), 미국토목학회기준(SEI/ASCE 8-02, SEI/ASCE 8-22)와 냉간성형 탄소강에 대한 미국철강협회 기준(AISI S100)에 의한 좌굴내력과 실험내력을 비교하였다. 인장재료시험을 반영한 EC3식에 의한 좌굴내력이 실험내력에 안전측면에서 가장 근접한 것으로 확인되었다.

Zn_80.1Cd_19.9Te 단결정 반도체의 전기-광학적 성질

姜鉉植,金豊久 全北大學校 師範大學 1982 사대논문집 Vol.8 No.-

Zn_80.1 Cd_19.9 Te single crystal were grown by Bridgmann method, and lattice constant(a_o=6.160A。) was determined from X-ray diffraction. Temperature dependence of the band gap and defect level of the interband have been found for mearurement of transmission, photoconductivity, and dark current at 30°K∼300°K. The energy band gap was 2.157eV and temperature coefficient was -5.3x10^-4ev/°K. Also, a defect level has been found at 0.176 eV.

CdTe 단결정 반도체의 전기 광학적 특성

강현식 全北大學校 基礎科學硏究所 1981 基礎科學 Vol.4 No.1

Temperature dependence of the band gap and several Interband defect levels of a CdTe; I single crystal which were prepared by Bridgemann method, were evaluated from a series experiment of transmission, photoconductivity, photoluminescence, dark current, and photocurrent variations v.s. light intensity as a function of temperature. The energy band gap were measured 0.61 eV, temperature coefficient β=-4.3×10 exp (-4) eV/^ok by photoconductivity experiments. The interband defect levels, V^-2_cd(0.11eV, β=-1.0×10 exp (-5) eV/^ok), Iodine impurity level(0.012eV at low temperature) and uncertain another level(0.049eV) which were guessed the Oxygen level were observed from above experiments. Also, several, phonon spectrum, LO(0.021 eV), TO_1(0.017eV), and TA_1(0.009eV were observed from photoluminescence experiments in temperature range 38 ^ok∼115^ok.

Ⅱ-Ⅵ족 화합물 반도체 단결정의 전기 광학적인 특성 연구 : ZnTe를 중심으로

강현식 全北大學校 基礎科學硏究所 1979 基礎科學 Vol.2 No.1

Semiconductor crystals of Ⅱ-Ⅳ compounds have more advantages of the large band gap than group Ⅳ or group Ⅲ-Ⅴ compound semiconductors. So, we selected ZnTe, ZnSe and ZnS among the Ⅱ-Ⅵ compounds. It was determined by transmission measurements that the energy gap of ZnTe, ZnSe and ZnS was 2.26eV, 2.67eV, 3.58eV. Especially, ZnTe crystals were grown by the Bridgman method in our Lab. And various heat treatments and impurity dopings were done. We found the impurities levels and Zn vacancy level are 0.11eV for silver, 0.15eV for copper and 0.05ev for V_zn in ZnTe crystals by wave length dependent on photocurrent measurements.

高屈折 眼鏡렌즈의 比較評價

姜賢植 대구보건대학 1988 대구보건대학 論文集 Vol.11 No.-

For a long time a crown glass with an index of 1.523 has become the standard so that, when old surfacing tools are used, a correction must be applied to the curve calculations to compensate for the difference in refractive index. The same type of compensation must be applied when organic lenses with an index if 1.498 or glass lenses with a high refractive index. are being surfaced. For a time, a new flint glass was became widely used. This glass was made by replacing the sand content by powdered flint adding lead to the mix ; this produced a softer and heavier glass with a refractive index of 1.654 and was used extensively in fused bifocal manufacture, but as the invisible bifocal grew in popularity, so did the need to find a better glass than flint with which to make the segments. The use of barium resulted in a marked reduction in chromatic aberration and this glass is now available in a wide range of indices to meet the need of the fused bifocal makers. Titanium, lanthanum and niobium are all used in the manufacture of glasses for fused bifocals and some multifocals are being made with high index glass in the distance portion. The amount of reflection from a spectacle lens can be reduced by the application in a vacuum coating machine of single, double or multiple layers of magnesium fluoride (MgF₂) or silicone dioxide (SiO₂). Since the maximum sensitivity of human eye in day time is around the wavelength 550nm, the index and the geometric thickness of an AR coating are usually based on this wavelength.

化學反應蒸着에 의한 CdS 多結晶 薄膜制作 및 그 特性硏究 (Ⅰ)

강현식,남궁윤,최선우,홍광준,최용대 全北大學校 敎育大學院 1986 敎育論叢 Vol.6 No.-

CdS thin film was fabricated by chemical bath deposition method and polycrystallined by the proper heat treatment. The physical properties of the amorphous and polycrystal of CdS thin film were observed and calculated by measuring the X-ray diffraction patterns, optical absorption, transmission and photoconductivity. From the present experiments, we obtained the energy band gap of the CdS polycrystal thin film to be 2.42eV and the In donor impurity level to be 0.025 eV below the conduction band : Another result was to be a_o=4.13Å and c_o=6.75Å for lattice constants of the hexagonal structure. Also, we attempted it to find the possibility of the application to photosensor. To apply cds this film to the photosensor more sufficiently, further experiments are required to accumulate data on such problems.

남자대학생의 심폐체력과 비만 및 대사증후군지표의 상관관계

강현식,이상화,이은혜 한국운동영양학회 2003 Physical Activity and Nutrition (Phys Act Nutr) Vol.11 No.3

모르타르 充塡組立式輕量판넬 接合部實驗

강현식 대한건축학회지회연합회 2008 대한건축학회연합논문집 Vol.10 No.4

The purpose of this study is to evaluate experimentally on the shear strength both of horizontal joint and vertical one for light-weight hybrid panel infilled with the light-weight foamed mortar. Horizontal joints consist of light-weight hybrid panel and composite slab. The experimental investigations are included the ultimate strength, yield strength, initial stiffness. As increasing the ratio of axial load, both the shear strength and the stiffness of the horizontal joint are enhanced as follows; 1.29 times in slip load, 1.36 times in ultimate strength, 1.61 times in initial stiffness. The friction factor of horizontal joints obtained by test result appears to be higher than 0.6, which is criterion value according to the Korean Standard. Shear tests for vertical joint are carried out both the shape of T-type and that of X-type being assembled with light-weight hybrid panel. As the test results, it is found that the density of light-weight formed mortar and the shape of joints are primely having an influence on both shear strength and failure mode for the vertical joint. It is obviously useful to making a specification for hybrid panel joint.

콘크리트 强度變化가 CFT短柱의 軸壓縮擧動에 미치는 影響

姜賢植,林書亨 진주산업대학교 2001 論文集 Vol.40 No.-

This paper aims to report the experimental study on the axial compressive behavior of tubular stub columns filled with variable concrete strength(f_c=500, 1,000㎏/㎠). The 24 specimen were tested to investigate the relationships between concrete strength and the ultimate strength of stub column. The effects of inner concrete on the failure mode, the ultimate strength, initial stiffiness and deformation capacity was discussed. From this experimental study, we found that the ratio of concrete strength was not proportion to the increasing rate of ultimate strength. This paper presents an experimental study on the strength and deformation of concrete-filled steel stub columns. In Korea, there is not the compressive design standard of CFT columns filled with high strength concrete(500㎏/㎠ and over). Therefore, this results can make a contribution to the development of our own design standard.

Cd_xZn_1-xTe 단결정을 이용한 초고속 THz 전자파의 emitter 특성연구(II)

강현식,김태규,이해익 全北大學校 科學敎育硏究所 2001 과학과 과학교육 논문지 Vol.26 No.-

Cd_xZn_1-xTe single crystals were secondary researched for ultrafast THz electromagnetic signal emitter, with proper and fine composition ratio x=0.00 , 0.05 , 0.10 , 0.15 , 0.20 and 0.25, after testing Cd_xZn_1-xTe to optical rectification principle. We have grown the crystals of Cd_xZn_1-xTe by advanced technology, and tested these mixed crystals with THz emitter and measured several properties. Particularly, we have found that Cd_0.2Zn_0.8Te crystals are the best emitters for generation of THz waves, also remain composition crystals are good emitters in same ranges. We check the optical saturation relations and the emitting signal variations depended on thickness of emitter and sensors. Finally we checked the saturation of optical reciprocal and luminescence by two photon processes