V₂O5ㆍB₂O₃ㆍA1₂O₃유리계의 B² 핵자기 공명의 넓은 선 분석

宋勝己 명지대학교 자연과학연구소 1985 자연과학논문집 Vol.3 No.-

The borad line of the ?? NMR in the ??·B₂O₃·A1₂O₃ glass system has been analyzed. The linewidth of the resonances varies as indicating that the spectra are braden-ed by a second-order quadrupole interaction. The ?? NMR spectrum for the ??·B₂O₃binary glasse system is characterized by a nuclear quadrupole coupling constant between 2.64 and 2.69MHz. e²qQ/h for the ??·B₂O₃·A1₂O₃ ternary system ranges from 2.65 to 2.83 MHz.

V_2O_5·B_2O_3 다결정 화합물의 전기전도도와 NMR에 관한 연구

宋勝己 명지대학교 1986 明大論文集 Vol.17 No.-

Four polycrystalline compounds in the vanadium borate system-2V_2O_5ㆍ1B_2O_3, 1V_2O_5ㆍ1B_2O_3, 1V_2O_5ㆍ2B_2O_3, 1V_2O_5ㆍ3B_2O_3-have been studied their structures by using the NMR technique and investigated the d.c. electrical conductivities. The B^11 NMR spectra of these samples are characterized by the superposition of a broad line due to BO_3 groups, an e^2qQ/h ranging from 2.63∼2.64㎒ and η from 0.09∼0.10. The nuclear coupling constant from the V^51 NMR spectra ranges from 0.75∼0.91㎒ for the case of η=0. The d.c. electrical conductivities have the values of the order of 10^-2∼10^-7(ohmㆍ㎝)^-1 and the activation energies 0.11∼0.17eV at high temperature region.

V₂O5-B₂O₃-Al₂O₃유리의 전기전도

송승기,김영훈 명지대학교 자연과학연구소 1990 자연과학논문집 Vol.8 No.-

V₂O??-B₂O₃-Al₂O₃계 유리의 직류전기전도도를 254∼480K 온도범위에서 측정하였다. 이들 시료의 전기전도도값은 온도의 함수로서 1.66×10-⁴-4.89×10-??(ohm·cm)-¹이었다. 이 결과로 Mott의 이론식 ρ=ρ??exp(-W/kT)을 만족하였으며, 시료내의 V₂O??양이 증가하면 직류전기도도값이 증가하였다. 활성화 에너지는 고온영역에서 0.20-0.39eV 이었다. 전기전도는 비단열 small-polaron hopping계로 확인되었다. The d.c. electrical conductivities of the V₂O??-Bl₂O₃glass compounds have been investgated in the temperature region between 254 to 480K. The measured values of electric conductivities of the glasses as a function of temperature are of the order of 1.66×10-⁴-4.89×10-?? (ohm·cm)-¹. These results are consistent with Motts theory, ρ=ρ??exp(-W/kT) and show that increasing the V₂O?? content in the samples causes an increase in the d.c. conductivities. The activation energy in the glass compounds has the value of 0.20-0.39eV in the high temperature region. The electrical conduction was characterized as nonadiabatic small polaron hopping regime.

V₂O5ㆍB₂O₃ㆍAl₂O₃유리계의 유전성

宋勝己,崔 悳,趙順基 明知大學校 自然科學硏究所 1984 자연과학논문집 Vol.2 No.-

Complex dielectric constants of the V?O? .B?O?.Al?O? glass system have been investigated as a function of frequency from 400 to to 10?Hz and temperature 100 to to 400?k. Dielectric constant and dielectric loss decrease with increasing frequency when temperature is constant, and increase with increasing temperature.

압착분말 방법에 의한 V₂O5·B₂O₃V₂O5·B₂O₃·Al₂O₃계 유리의 전기전도도 측정

宋勝己,金祥洙 明知大學校 自然科學硏究所 1983 자연과학논문집 Vol.1 No.-

The electrical properties of ??·B₂O₃,·??·B₂O₃·Al₂O₃glasses have been investigated in the compressed powder form. The measured d.c electrical conductivities of these samples as a function of temperature have values of the order of 5×??∼?? ?? for ??·B₂O₃,2×??∼5×?? ?? for ??·B₂O₃Al₂O₃,and itsresults are satisfied with Mott's theory,σ=?? exp(??). It has been found that increasing the ?? molar content caused an increase in their d.c conductivity. And the activation energy for d.c conductivity has three values.

V_2O_5-B_2O_3-Al_2O_3 유리계의 B^11 핵자기 공명에 관한 연구

송승기,박만장 명지대학교 1982 明大論文集 Vol.13 No.-

The phase diagram of the V_2O_5―B_2O_3 and V_2O_5―B_2O_3―Al_2O_3 glass system has been accomplished. Nuclear magnetic resonance (NMR) techniques have been employed to investigate the environment of boron in the ternary glass system. The B^11 NMR spectra in the xV_2O_5 (95-x) B_2O_3 5Al_2O_3 and xV_2O_5 (90-x)B_2O_3 10Al_2O_3 glass system exhibit both broad line characteristic of BO_3 unit with bridging oxygens and narrow resonance line due to the borons in four coordinated to oxygens.

THE NATURAL SCIENCE RESERCH INSTITUTE MYONG-JI UNIVERSITY

송승기,장동빈 明知大學校 自然科學硏究所 1987 자연과학논문집 Vol.5 No.-

The D.C electric conductivities of the V₂O??-B₂O₃-A1₂O₃polycrystalline compounds have been investigated by the compressed powder method in the temperature region between 120K to 500K. The measured value of electric conductivities of the polycrystalline compounds as a function of temperature are of the order of 1.13×10-³~7.88×10-¹²(ohm. cm)-¹. These results are consistent with Motts theory, σ = σ??exp(-W/kT) and show that increasing the V₂O?? content in samples causes an increase in their d.c. conductivities. The activation energy in the polycrystalline compounds has the value of 0.18 - 0.31eV in the middle~high temperature region. Complex dielectric constants of the V₂O??-B₂O₃-A1₂O₃polycrystalline compounds have been found as a function of frequency from 400 ㎐ to 100㎑ and temperature from 150K to 300K. Dielectric constrant and dielectric loss decrease with increasing frequency when temperature is dept constant and increase with increasing temperature when frequency is kept constant, satisfying the Debye equation.

상온에서 혼합계 [NaNO_2]_1-x[KNO_3]_x의 ^14N 핵사중극 공명연구

박영민,송승기 명지대학교 대학원 1998 대학원논문집 Vol.2 No.-

The impurity effect of mixed systems [NaNO_2]_(1-X)[KNO_3]_x in the range of 0 ≤x ≤0.41 have been studied by x-ray diffraction and ^14N nuclear quadrupole resonance method, at room temperature. The x-ray diffraction patterns for the mixed system show that the introduced impurity of KNO_3 into NaNO_2 exists in both NaNO_2- and KNO_3- matrixes at the same time. The ^14N NQR frequency remains constant independently as increasing impurity KNO_3 in mixed system. Configuration of electric field gradient(EFG) at the position of resonance nucleus does not be changed by impurity effect in this system. The line width is increased at x=0.08 due to the inhomogeneity of EFG, but decreased as increasing impurity which causes the active motion of point defect. The decreasing of the ^14N NQR signal intensity as increasing of the concentration of KNO_3 was explained by the "all or nothing" model

77K와 상온사이에서 (NH_2)_2CO·H_3PO_4의 ^14N 핵사중극 공명 연구

박현진,송승기 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

Four nuclear quadrupole resonance frequencies, nuclear quadrupole coupling constants, asymmetry parameters, average torsional frequency in the crystal lattice motion and moment of inertia in the oscillator are found for (NH_2)_2CO·H_3PO_4(urea-phosphoric acid compound) powder sample by the ^14N Pulsed NQR(nuclear quadrupole resonance) technique in the temperature range from 77K to 300K. The results of measurements show that there are two kinds of nitrogen site, N_1 and N_2, with different invironments in the crystal. Temperature dependence of resonance frequency(V_-2) showed that frequency variation is in opposition with most common experimental results and Bayer's theory. The magnitude of the torsional frequency and resonance frequency in static lattice were determined by the approximate calculation and they were compared with lattice dynamics in pure urea.

고온 초전도체 Gd₁Ba₂Cu₃O7-y의 임계전류밀도에 관한 연구

전인,송승기,김영호 명지대학교 자연과학연구소 1989 자연과학논문집 Vol.7 No.-

고상반응법으로 고온 초전도체 Gd₁Ba₂Cu₃O??를 제작하여 임계전류밀도를 연구하였다. X-선 분말 회절실험결과 시료는 직방정계 구조임을 보였다. 초전도 전이 온도는 92K로 측정되었으며, 자기적 감수율은 ?? emu/㎤.Oe으로 나타났다. 수송 임계전류밀도(Jc)는 70 A/㎠이며, 시료내의 자기장이 증가함에 따라 감소하였다. Bean의 공식을 이용하여 구한 자기 임계전류밀도는 수송 임계전류밀도의 약 10²배이다. The critical current density of high-Tc superconductor Gd₁Ba₂Cu₃O?? prepared by solid state reaction method has been studied. From the results of X-ray powder diffraction pattern, the sample is found to be orthohombic structure. Teh superconducting transition temperature is detected at 92 K and the value of magnetic susceptibility are measured to be ?? emu/㎤.Oe. Transport critical current density(Jc) has the value of 70A/㎠ and decrease with increasing magnetic field in the sample. Magnitic critical current density from Bean's law is about 10²times as large as the transport Jc.