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.

Co(NH₂)₂H₂O₂의 N 핵사중극 공명연구

김복수,서용문,박영민,송승기 명지대학교 자연과학연구소 1998 자연과학논문집 Vol.17 No.-

Urea계통의 화합물인 urea hydrogen peroxide(CO(NH₂)₂H₂O₂)에 대한 ??N 핵사중극 공명실험을 77k에서 상온까지 실시하였다. 각각의 온도에 대한 위 공명진동수의 온도의존성과 공명선폭을 구하였으며,스핀-스핀 완화시간 및 스핀-격자 완화시간을 측정하여 결정의 동역학적인 측면에서 urea hydrogen peroxide를 연구하였다. 핵사중극 공명진동수는 온도가 증가함에따라 Kushida-Bayer type의 온도의존성을 나타내었으며, 스핀-스핀 완화시간과 공명선폭은 온도가 증가함에 따라 감소하는 경향을 보였다. 스핀-격자 완화시간은 150K 이하에서는 두개의 항으로 나타났으며, 200K를 기준으로 결정내의 분자운동이 달라지는 것으로 나타났다 ??N NQR invesigation has been made of the spin-spin and spin-lattice relaxation in urea hydrogen peroxide,Co(NH₂)₂H₂O₂ The line spectra point out only a slight change in the electonic distribution around the nitrogen site in NH groups as a result of protonation in urea, in agreement with the results of earlier stueies. A relativelyu large discrepancu in the relaxation spectra conpared with those in pure urea, on the other hand, indecates the presence of the fragments such as C=N??H₂, the motion of which seems to be one of the main contributions to the relaxation on this xomplex in addition to the quadropolar procerss. Our study demontrates this tendency apparently. The temperature behaviour of the relaxation times will be discussed with regard to the characteistics of the possible metion of the fragments.

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.

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.

V₂O5·B₂0₃·Al₂0₃유리계의 N₄ : N₄in the V₂O5·B₂0₃·Al₂0₃Glass System

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

B' NMR spectra have been used to study the structure of glasses in the system ??·B₂O₃.Al₂O₃. The fraction N₄of boron atoms in BO₄units is measured and analyzed according to a structural model. In this study, it is found that the N₄values are 0.013±0.03∼0.038±0.005 which are very small in values, indicating that the interaction between the electric quadrupole moment and the electric field gradient in boron sites are strong in this compound.

고온 초전도체 Y₁-x Ndx Ba₂Cu₃O7-y의 임계 전류밀도에 관한 연구

박영민,전인,송승기 명지대학교자연과학연구소 1991 자연과학논문집 Vol.9 No.-

고온 초전도체 Y₁-??Nd??Ba₂Cu₃O??-??(x=0.0,0.2,0.4,0.6,0.8,1.0)를 고상 반응법을 이용하여 제작하여 제작하였다. X-ray 회절실험 결과로 부터 격자상수를 구했다. x가 증가함에 따라 a,b,c값이 증가하였고 x=0.6과 x=1.0에서 anomaly 현상을 보였다. SEM 사진을 통한grain size는 x= 0.0,1.0에서 2∼3μm, x=0.6,0.8에서 4/μm, x=0.2,0.4에서 5μm 정도로 나타났다. 온도 변화에 따른 비저항 측정으로 구한 초전도 전이온도는 모든 시료에 대해 85∼92K 사이에 존재하였고 x가 증가함에 따라 감소하였다. 수송 임계전류밀도는 20-92 A/㎠사이에서 측정 되었으며 시료내의 Nd 치환량이 증가하면 J?는 증가하였고 x=0.4에서 anomaly 현상이 나타났다. 자기장을 가해준 상태엣 측정한 수송 임계전류밀도는 자기 장이 증가함에 따라 x=0.0 시료에서 급격히 감소하였고 Nd가 많이 치환된 시료에서는 감소율이 작았다. High-T??superconductor Y₁-??Nd??Ba₂Cu₃O??-??(0.0, 0.2, 0.4, 0.6, 0.8, 1.0)has been prepared by the solid state reaction method. Lattice constants are calculated from the result of X-ray diffraction pattern. The lattice constant a, b, and c are increased as increasing x except for x=0.6 and 1.0 samples. SEM photograph showed that the grain size is 2∼3μm for x=0.0 and 1.0 samples, 4μm for x=0.6, 0.8 and 5μm for x=0.2, 0.4 samples. The superconducting transition temperature determined by the temperature dependence of resistivity are detected between 85K and 95K decreased as increasing x. Transport current density was observed between 20 and 92 A/㎠ and J?? increased as increasing Nd concentration in the sample except for the x=0.4 sample. Transport current density of x=0.0 sample decreased abruptly with increasing applied magnetic field and the smaple of large Nd concentration has the slowly decreasing transport current density with inereasing magnetic field.

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.

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.

용매의 선택에 따른 전도성 Polyaniline의 자기적 성질변화

오응주,서정선,노태호,류광선,정상국,송승기 명지대학교 자연과학연구소 1994 자연과학논문집 Vol.11 No.-

Polyaniline(emeraldine base:EB)를 pH에 따라 HCI로 1차 doping을 한후ESR을 사용하여 자기적 성질을 조사했다.또한 emeraldine base를 camphorsulfonic acid(HCSA), dodecylbenzene sulfonic acid(HDBSA)등의 산으로 1차 doping 시키고 이것을 m-cresol, acetic acid, 및 formic acid에 녹여 2차 doping을 한 후 SQUID 를 이용하여 자기적 성질을 측정하였다. Doping에 사용된 HCI용액의pH가 감소함에 따라 ESR 신호의 강도가 증가하였으며, 이로부터 doping에 따라 상자성을 나타나게 하는 화학종이 가타다는 것을아타내고 있다.m-cresol내에서 HCSA 및 HDBSA로 각각 doping된 EB-CSA/m-cresol 과 EB-DBSA/m-cresol 시료 무두 상자성을 나타내었고, 온도가 증가함에 따라 자하율값이 감소하는 경향을 나타내었다.χ?값은 2.18x10?과 7.87x10?emu/mol2-rings unit 보이며 두 스핀에 대한 Fermi 에너지 level(E?)에서의 상태밀도를 나타내는 N(E?)는 0.67과 0.24 상태(eV/2-rings unit?)로 나타났다.Camphorsulfonic ascid(HCSA)로 doping 된 EB를 m-cresol, acetic acid 및 chloroform 등 다른 용매에서 처리시 관찰된 자화율의 변화를 온도에 의존하지 않는 χ?값과 온도에 의존하는 χ? 값으로 구분하여 curie spin의 온도의존성을 규명하였다. Dependency of magnetic properties of polyaniline(emeraldine base:EB)on the pH of HCI used in doping was inverstigated by electron spin resonance spectroscopy. Emeraldine base doped with functionalized acid (primary dopant) such as camphorsulfonic acid (HCSA), dodecylbenzene sulfonic acid(HDBSA) was processed in various solvents (m-cresol, acetic acid, formic acid etc.)into homogeneous solution and free standing film and its magnetic properties were measured by SQUID. The intensity of ESR signal was increased with decrese in pH of HCL solution and paramagnetic behavior of doped polyaniline due to the formation of polaron upon doping could be confoirmed from these results. The same g value of 2.004±0.001 measured for all of the samples means that the chemical species which show paramagnetism are sasme. Polyanilines doped with HCSA and HDBSA in m-cresol showed paramagnetism and decrease in susceptibility with increase in temperature. χ? value was appered 2.18x10? and 7.87x10? emu/mol2-rings unit and N(E?) which is density of states at Fermi energy level for two spins was 0.67 and 0.24 state eV? 2rings unit? respectively. The changes in susceptibility of polyanilines doped with HCSA in m-cresol, acetic acid, formic acid etc. were divided into temperature independent χ? term and temperature dependent χ? term and temperature dependency of curie spin concentration was examined.