刑狀記憶合金의 擬彈性 機構에 關한 硏究

張忠根,崔哲圭,琴彩 충남대학교 기초과학연구소 1982 연구논문집 Vol.3 No.-

The pseudo-elasticity in the ternary alloy (Cu_74 Zn_20)Al_6 is investigated experimentally and the results are interpreted in terms of the continual mechanical twinning. Measured are the effects of temperature on such as stress-strain curve, critical shearing stress, twinning stress and load concentration. Also the relation between shearing stress and strain rate, and cyclic strain-stress curve are obtained experimentally. The experimental results of the present study are in good agreement with the Bolling-Richman theory which is a model-independent description of mechanical twinning. The transformation temperature of (Cu_74 Zn_20)Al_6 alloy are M_f : 333°K, Ms : 358°K, As : 353°K, and A_f : 393°K. The stress-strain curve shows clearly the pseudo-elasticity which is related with the mechanical twinning generated in the sample. The critical shear stress has the positive temperature-dependence indicating that the dominant process in the sample is a deformation by mechanical twinning rather than the deform by slip. Also, the temperature effects on work hardening, the relation between twinning stress and load concentration, and other measurements all indicate that the continual mechanical twinning is the main cause of the pseudo-elasticity in the Cu-based memory alloy (Cu_74, Zn_20)Al_6.

炭素鋼中의 크롬擴散과 空孔機構

張忠根,金基元,千光鉉 충남대학교 자연과학연구소 1974 學術硏究誌 Vol.1 No.1

Chromium diffusion into the carburized iron is measured over the temperature range 800℃-1. 200℃. The diffusion coefficient is obtained by the calculation from the diffused time and depth. Chromium diffusion into the carburized iron appears notably over the temperature 900℃, and the diffusion coefficient of chromium decreases with an increase of the cardon concentration ironin. The above experimental results have shown that a major penetration mechanism is jumping into the vacancy which has been made in the transition from BCC iron structure to FCC type. The relationships of the depth of penetration and diffusion coefficient with the Carbon concentration under the constant temperature is given by the equation X_(p)=50(1-0.96C). D=0. 028X_(p)^(2)

球狀黑鉛鑄鐵의 鹽浴窒化

張忠根,金水泳,李相益 충남대학교 자연과학연구소 1977 學術硏究誌 Vol.4 No.1

Liquid nitriding is being is used for machine parts to improve fatigue strength and resistance to wear and seizure in spheroidal graphite cist iron. The difference in matrixes with as cast, pesrlite or ferritic structure in the iron has an important effect on nitriding. in the present work, spheroidal graphite cast irons with different matrixes nitrided by the tufftride process at 570 C for 1-6 hrs for a bask study on the nitriding of spheroids1 graphite castiron. The relationship between maximun hardness and nitriding time can be obtained as follows. In ferritic matris, hardness of matrix increased from 250Hv for 6hrs of nitriding time. In pearlite matrix, hardness of matrix increased from 390Hv to 560Hv. for 6 hrs of nitrding time.

질화철의 경도에 미치는 탄소와 규소의 영향

장충근,권혁무 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.2

The effect of carbon and silicon on the hardness of nitrided iron at the temperature range of 650℃- 850℃ was investigated, In the case of carbon added iron, the peak hardnesses and surface hardness were increased but the thickness of nitrided layer was decresed than the nitrided pure iron, In the case of silicon added iron, the internal hardness and surface hardness were decreased than the carbon added iron.

酸化銅의 Switching 現象

張忠根 충남대학교 자연과학연구소 1976 學術硏究誌 Vol.3 No.1

The switching behavior of copper oxide has been investigated experimentally. The filamentary nature of the current and the formation of a copper channel have been observed to be associated with the process of switching. The effect of the dimension of the device on the V-Ⅰ characteristics is also observed. The switching transition is more easily brought on a t high temperature and the switching time becomes shorter as the pressure decreases below the atmospheric pressure.

철-질소 2원계에서 r´-phase의성장에 관한 연구(Ⅱ)

장충근,김수영 충남대학교 자연과학연구소 1983 忠南科學硏究誌 Vol.10 No.2

In order to observe the effect of adding silicon and carbon in to the prepared Fe-Si and Fe-C alloyed specimens which were nitrided by using a nitrogen gas agent in the temperature range of 650-850℃. The effect of silicon and carbon on the frequency factor, activation energy and surface hardness of the specimens were also investigated. The relationships between the activation energy and the amount of silicon and carbon were obtained as Q(msi)=27.2 exp 23.92(msi) Kcal/mole Q(mc)=27.2 exp 30.70(mc) Kcal/mole The surface hardness of the specimens increased sharply by nitriding, but it decreased slightly when nitrided for a considerably long time, while the internal hardness increased.

철-탄소 합금에서 r'- phase의 성장에 미치는 탄소의 영향

장충근,오헌진,오희필 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.2

To obtain the diffusion coefficient of nitrogen in Fe-C alloys, the 0-3% C-Fe alloy was nitrided by the liquid drop nitriding method in the temperature range of 650 C- 850 C. The main results observed are: (1) The frequency factor Do of nitrogen in 0-3%C-Fe alloy; Do(mC) = 1.17 exp[-1.08(mC)]㎠/sec (2) The activation energy Q of nitrogen in the alloy; Q(mC)= 27.2 exp [30.7(mC)]Kcal/mole (3) And finally, the diffusion coefficient of nitrogen in 0-3%C-Fe alloy is D_(N)= Do(mC) exp[-Q(mC)/RT] ㎠/sec

沃化水銀 單結晶의 成長과 그 物理的 特性에 關한 硏究

田載植,張忠根,吳熙弼 충남대학교 기초과학연구소 1984 연구논문집 Vol.5 No.-

Investigation on the physical properties of mercuric iodide single crystals grown by both means of liquid and vapour growth was performed. In addition to the measurement of band gap energy and hardness of the crystals grown, studies on the relations between nucleation, supersaturation and transport rate as a function of source temperature in the process of vapour growth as well as solvent evaporation rate, crystal density and crystal size as a function of growing time in liquid growth were also carried out. As a result of the analysis, it is shown that the total number of crystallites, Ns, in vapour growth is given by In N_s = -4.47 × 10 exp (-2)G + 0.012T were G=1/ln^2 (1+r) and r is supersaturation, and T is source temperature in K, whereas the mass transport rate, J, is expressed by J = -0.96 × 10 exp (3)T^-1 + 2.52. In liquid growth, the solvent evaporation rate was found to be the most important factor that affects the pattern of the crystal grown. Density and band gap energy measured were, on average, 6.3g/㎤ and 2.1 eV, respectively.

沃化水銀 (Hgl_2)半導體 放射線檢出器 製作에 關한 硏究

田載植,張忠根,吳熙弼 충남대학교 기초과학연구소 1983 연구논문집 Vol.4 No.-

As a preliminary study of fabricating semiconductor gamma-ray detector for practical use at room temperature, α-phase HgI_2 single crystals were grown by means of statical evaporation after appropriate purification of commercially available chemical grade HgI_2 powder. For the crystals grown, examination or measurements of such physical properties as thermal resistivity, photoconductivity and band gap energy including an evaluation of spectrometric characteristics, were carried out. The band gap energy were found to be 2.11eV. Results are summarized and illustrated in graphical forms. Throughout the study it is concluded that a priori purification of HgI_2 condition of crystal growing, polishing the surface and ohmic contact in fabricating a detector are particularly important parameters on which quality of the detector is largely dependent.

KCI, KBr에 關한 X-線 廻折硏究

李善鏞,金永銓,張忠根,徐日煥 충남대학교 자연과학연구소 1982 忠南科學硏究誌 Vol.9 No.1

The crystal structure of potassium chloride and potassium bromide have been determined by X-ray diffraction method. Both unit cells are face-centered cubic, F(4/m)3￣(2/m) z=4 but a=5.2857Å, V=248,348Å^3, D_c=1.989 gr/㎤ for KCl and a=6.5891Å, V=286.074Å^3, D_c=2.756 gr/㎤ for KBr. the structures were solved by graphical method using thirteen KCl and eleven KBr powder diffractometer data. The agreement between the experimental and theoretical integrated intensities of the reflecting planes is fairly good. The crystal are aggregates of positive and negative ionic atoms. Each atom has six nearest neighbors of the other kind. The distances between unlike atoms are 3.1429Å in KCl and 3.2945Å in KBr.