• Korean Journal of Materials Research
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• v.3 no.4
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• pp.422-423
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• 1993

In this short note, we report the result of measurement for the ferro- to paramagnetic phase transition temperature, that is Curie point of bulk gadolinium. This note is written to give the solid validity for the previous measurement of Curie point shift of gadolinium film (1. Rhee, E. Lee and S. Lee, Kor. J. of Mat. Research,3, 3, 1993). The Curie point of bulk gadolinium is determined by measuring the resistance of sample as function of temperatures. At Curie point, we can observe the resistivity anomaly which arises due to the heat capacity difference between below and above Curie point. Finally, the curie point of bulk gadolinium is found to be 19.2${\pm}$0.$3^{\circ}C$.

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.156-160
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• 1996

The purity dependence of the Curie point and the critical exponent of heat capaicty has been studied by measuring the resistvity of nickel samples with several different purities. The resistivity was measured by the 4-point ac method with a lock-in amplifier. The Curie points determined from in-phase and out-of-phase signals were found to be consisten twith each other . We found that the Curie point and the critical exponent of heat capacity did not depend on the purity of samples.

• Analytical Science and Technology
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• v.5 no.4
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• pp.373-379
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• 1992

The pyrolysis conditions for the thermal isomerization products of pinane were carried out by the furnace type pyrolyzer and the curie-point pyrolyzer equipped with gas chromatograph and mass spectrometer. It was confirmed that curie-point type is much better furnace type, and high yield (70%) of citronellene was obtained from pinane as the main isomerization product under the best conditions by curie-point type. The optimum conditions of pyrolysis are $590^{\circ}C$ for 4 sec. and the major products were indentified as citronellene, m-Menth-6-ene, m-Menth-1-ene and 1-Methyl-4-(1-methylethylidiene) cyclohexane.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.63-68
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• 1994

The Curie point annealing effects on electrophysical phenomena at the magnetized strontium ferrite(SrO$\cdot$ 6$Fe_{2}O_{3}$) ceramics electrode/10$^{-3}$M KC1 aqueous electrolyte interfaces have been studied using cyclic voltammetric, normal pulse voltammetric, chronocoulometric, and electrochemical impedance techiques. After the Curie point annealing the magnetic flux densities of the speciment was decreased from 900-1100 gauss to 1-2 gauss, i.e. demagnetized. The real component of interfacial impedance was decreased from 7280-7320 ohm to 790-830 ohm. The adsorption and the charge on the electrical double layer was increased from 0 $\mu$C to -58 $\mu$C. The Curie point annealing and the related electrical double layer effect can influence not only the electrophysical properties of the strontium ferrite ceramics electrode itself but also the electrochemical phenomena at the electrode interface. This experimental results suggest that the Curie point annealing and the related electrical double layer effect can be applied to electrochemical magnetic sensors.

• Journal of Korean Vacuum Science & Technology
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• v.1 no.1
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• pp.13-18
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• 1997

The critical phenomena in nickel films have been studied by observing the resistivity behavior with temperatures near the Curie point. We observed the thickness dependence of the Curie point in nickel films, that is, the thinner the film is, the lower the Curie point is. This is as expected. Using the heat capacity data, we also found the amplitude ratios of bulk and film systems to be 1.222 and 1.197(average0, respectively. These values are cose to the theoretical prediction of 1.46 given by the Heisenberg, S=$\infty$ Model.

• Nuclear Engineering and Technology
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• v.31 no.6
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• pp.1-7
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• 1999

An innovative concept for a passive reactor shutdown system, so called self-actuated shutdown system(SASS), is inevitably required for the inherent safety in liquid metal reactor, which is designed with the totally different concept from the usual reactor shutdown system in LWR. SASS using Curie point electromagnet(CPEM) was selected as the passive reactor shutdown system for KALIMER (Korea Advanced Liquid MEtal Reactor). A mock-up of the SASS was designed, fabricated and tested. From the test it was confirmed that the mockup was self-actuated at the Curie point of the temperature sensing material used in the mockup. An articulated control rod was also fabricated and assembled with the CPEM to confirm that the control rod can be inserted into core even when the control rod guide tube is deformed due to earthquake. The operability of SASS in the actual sodium environment should be confirmed in the future. All the design and test data will be applied to the KALIMER design.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.1
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• pp.1-5
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• 2001

P(VDF/TrFE) copolymer thin films with 70/30 and 80/20 mol% VDF (polyvinylidene fluoride) and TrFE (trifluoroethylene) rates were prepared by using a vapor deposition method, During thin films were prepared, the substrate temperatures were maintained at 30 $^{\circ}C$ and 120 $^{\circ}C$, and the heating source temperature was fixed at 350 $^{\circ}C$. Contary to PVDF homopolymer, P(VDF/TrFE) copolymers showed the Curie point(Tc) below the melting point. The Curie point (Tc) and the melting point of the P(VDF/TrFE) copolymers were changed as a function of substrate temperature and the VDF mol%. The Curie point and the melting point of P(VDF/TreFE) thin films decreased and increased with increasing substrate temperature, respectively. Also with increasing VDF mol%, the melting point decreased slightly, however the Curie point increased.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.81-83
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• 1989

This study, involving thirty-two patients with carcinoma of uterine cervix treated by high dose rate intracavitary irradiation using a remotely controlled afterloading system, compares the doss at point A and 8 with the Curie-minutes prescription. A linear least-square regression analysis was used to compare the two sets of date. Correlation coefficients between doses at points A and B and the Ci-min prescription are 0.92 (p<0.001) and 0.90 (p<0.001), respectively, and linear relationship is observed between these two system. The limitation and significance of the comparison of the two approaches to intracavitary dosimetry is discussed.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.8-15
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• 1997

This study was carried out to present a analysis of pyrolytic degradation of 4-hydroxy-3-methoxybenzal dehyde(vanillin) pyrolyzed at $330^{\circ}C{\sim}920^{\circ}C$ by Curie-point pyrolyzer connected with GC/MSD by on-line system. Identified by GC/MSD were 100 pyrolytic products of vanillin. The pyrolysis of the compound gave benzene, phenol, 1,3-cyclopentadiene, methyl benzene, benzaldehyde, benzofuran, and cresol as major products, which were produced by pyrolytic degradation and synthesis of vanillin radicals.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.165-169
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• 1999

The thermal diffusivity of lead germanate single crystal was measured from room temperture up to the $200^{\circ}C$ by heating method. The thermal diffusivities were measured as k=0.0117, 0.0105, and $0.0112cm^2/^{\circ}C$ at $30^{\circ}C$, $177^{\circ}C$, and $180^{\circ}C$, respectively. It is identified that the heat capacity of the lead germanate single crystal is maximum at $177^{\circ}C$, and this point is phase transition temperature of $Pb_5Ge_3O_{11}$ single crystal.