• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.176-181
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• 1984

Linear free energy relation ship(LFER) on the insecticidal activity of O,O-diethylphenylphosphate (A) and 3,5-dimethylphenyl-O,O-diethylphosphate (B) derivatives were studied by EHT MO calculation method and regression analysis method. LFER between varying substituent constants and $pI_{50}$ constants of phosphates, (A) & (B) were calculated with applying Hammett, Okamoto-Brown, Taft and Swain-Lupton's DSP equations;percent resonance effect(R) and field effect(F) of (A) were %R=33.5 & %F=66.5 and also that of (B) were %R=2 & %F=98, respectively. On the basis of above findings, the insecticidal activities were similar for both (A) and (B), but (B) have larger field and inductive contribution than (A), due to the 3,5-dimethyl group of (B).

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2221-2223
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• 1999

Axial magnetic field($B_z$) generated by special electrode construction in vacuum interrupters(Vl) is used to extinguish electric plasma arcs because that restrains this form expending. So VI applied axial magnetic field has more interruption capacity as compared with other VI. Also, the profile of toroidal field($B_{\theta}$) generated by $B_z$, is important to VI design. In this study, it was represented that the behavior of vacuum arc. In addition, The relationship between $B_z$ and $B_{\theta}$ was represented by using Dynamo theory. I hope that this study will be a good data in design of vacuum interrupters.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.137-143
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• 2003

Purpose : B1 field of birdcage RF (radiofrequency) coil that is used most for brain imaging in magnetic resonance imaging (MRI) decreases toward endring from the coil center. We investigated how much RE B1 homogeneity effect the endcap shield brings form the coil center as it towards to endcap region. Materials and Methods : We compared RF B1 field distribution by each finite difference time domain (EDTD) simulations for lowpass, highpass and hybrid birdcage RF coils. We selected the highpass birdcage RF coil that was the highest RF B1 field condition as simulation result, and studied how much RF B1 homogeneity effect was occurred when endcap shield was applied to endring area. Results : B1 field of the highpass birdcage RF coil was higher than other birdcage RF coil types as simulation result. However, the RF B1 homogeneity was lower than other coil types. RE B1 field of highpass birdcage RF coil with endcap shield is similar with RF B1 field of hybrid birdcage RF coil and the overall RE B1 homogeneity in sagittal direction was better. Conclusion In this paper, proposed method can apply improving RF B1 homogeneity of RF coil in clinical examination.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.199-205
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• 2005

DNA fingerprint patterns of 8 Brucella reference strains and 15 B. abortus field isolates were characterized by repetitive element sequence-based PCR (rep-PCR) using BOX- and ERIC-primers in this study. AMOS PCR differentiated all Brucella field isolates from B. abortus RB51, a vaccine strain by producing a B. abortus-specific 498 bp band. Rep-PCR using BOX-primer produced 13 to 18 bands with sizes of between 230 and 3,300 bp, and discriminated Brucella strains to the species level except B. canis and B. suis. PCR products amplified with ERIC primers were, however, not appropriate for differentiating the Brucella isolates. DNA fingerprint patterns for all B. abortus field isolates were identical among them and were put on one cluster with B. abortus biovar 1 reference strain in the dendrogram, indicating they were highly clonal. These results suggested that rep-PCR using BOX primer might to be a useful tool for calculating genetic relatedness among the Brucella species and for the study of brucellosis epidemiology.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.261-261
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• 1999

We observed leveling-off of the resistance in granular In/InO$_x$ thin films in the zero-temperature limit. The temperature T$_b$ at which the leveling-off appears gets larger as the sheet resistance R$_n$ increases. This is consistent with the concept that the leveling-off of the resistance is due to the dissipation of the bosonic phase and that the dissipation is enhanced as the resistance increases. The magnetic field dependence of the saturated resistance R$_b$ at low temperatures fits the modified square-root cusp-like form R$_b$/R$_n$=α exp[-b(B/B$_c$-1)$^{-1/2}$] for the magnetic field in the range B$_c$$_f$ where B$_c$ is the onset magnetic field of the resistance leveling-off. α and b are constants of order 1. For B>B$_f$ tansport properties are described by the theory of the fermi insulator. From the results, we attribute the leveling-off to the dissipative quantum tunneling of vortices, which supports the models predicting the vortex-motion-induced insulating phase related with the concept like"dirty boson" [1]l and "hose metal" [2].

• Transactions of Materials Processing
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• v.13 no.1
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• pp.33-38
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• 2004

A new approach for the design of extrusion die surface of arbitrarily shaped section is presented. In order to generate the extrusion die surface. an automatic surface construction method based on B-spline surface and scalar field theory is proposed. The isothermal lines and stream lines designed in the scalar field are introduced to find the control points which are used in constructing B-spline surfaces. Intersected points between the isothermal lines and stream lines are used to construct B-spline surfaces. The inlet and outlet profiles are precisely described with B-spline curves by using the centripetal method for uniform parameterization. The extrusion die surface is generated by using the cubic curve interpolation in the u- and v-directions. A quantitative measure for the control of surface is suggested by introducing the tangential vectors at the inlet and outlet sections. To verify the validity and effectiveness of the proposed method, automatic surface generation is carried out for extrusion dies of arbitrarily shaped sections.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.107-110
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• 2000

($^{11}$B NMR measurements have been performed on single crystals of LuNi$_2$B$_2$C superconductor to investigate vortex lattice structures and dynamical behavior. The spectrum in the superconducting state is significantly broadened by local field inhomogeneity due to the vortex lattice and the peak point of the spectrum shifts toward low magnetic field due to the imperfect field penetration. The linewidth of the spectrum reflecting local field variation is much smaller than expected for conventional vortex lattices and shows peculiar increase at low temperature. Furthermore, the transverse relaxation rate, 1/T$_2$, probing the slow motion of vortices, exhibits a single peak as temperature decreases. These prominent results highlight significant fluctuation of vortices even for this low T$_c$, and nearly isotropic 3D superconductor.

• Journal of Ginseng Research
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• v.38 no.1
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• pp.73-77
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• 2014

Field and nutrient cultures of American ginseng (Panax quinquefolius L.) were used to establish foliar symptoms related to boron (B) concentration in leaves and soils, and to evaluate radish as a time-saving model system for B nutrition. Application of excess B, 8 kg/ha versus the recommended 1.5 kg/ha, to field plantings of 2-, 3-, and 4-yr-old American ginseng plants just prior to crop emergence caused, within 4 wk after crop emergence, leaf symptoms of chlorosis followed by necrosis starting at the tips and progressing along the margins. The B concentration in leaves of 2-4-yr-old plants receiving 1.5 kg/ha Bwas $30{\mu}g/g$ dry mass compared to $460{\mu}g/g$ dry mass where 8 kg/ha B was applied. Similarly, B concentration in soils receiving the lower B concentration was 1.8 mg/g dry mass and $2.2-2.8{\mu}g/g$ dry mass where the higher B concentration was applied. Application of 8 kg/ha B reduced the dry yield of 3rd-yr roots by 20% from 2745 kg/ha to 2196 kg/ha and 4th-yr roots by 26% from 4130 kg/ha to 3071 kg/ha. Ginseng seedlings and radish were grown under greenhouse conditions in nutrient culture with four B concentrations ranging from 0 mg/L to 10 mg/L. At 5 mg/L and 10 mg/L ginseng and radish developed typical leaf B toxicity symptoms similar to those described above for field-grown plants. Increasing B in the nutrient solution from 0.5 mg/L to 10 mg/L decreased, in a linear fashion, the root and leaf dry mass of ginseng, but not radish. Given the many similarities of ginseng and radish to B utilization, radish might be used as a timesaving model system for the study of B, and other micronutrients, in the slow-growing perennial ginseng.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.96-100
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• 2012

In high static field magnetic resonance imaging(MRI) systems, $B_0$ fields of 7 T and 9.4 T, the impressed RF field shows larger inhomogeneity than in clinical MRI systems with B0 fields of 1.5 T and 3.0 T. In multi-channel RF coils, the magnitude and phase of the input to each coil element can be controlled independently to reduce the non-uniformity of the impressed RF $B_1^+$ field. The convex optimization technique has been used to obtain the optimum excitation parameters with iterative solutions for homogeneity in a selected ROI(Region of Interest). To demonstrate the technique, the multichannel transmission line coil was modeled together with a human head phantom at 400 MHz for the 9.4 T MRI system and $B_1^+$ fields are obtained. In this paper, all the optimized $B_1^+$ in each isolated ROIs are combined to achieve significantly improved homogeneity over the entire field of view. The simulation results for 9.4 T MRI systems are discussed in detail.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.30-35
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• 2017

The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ($J_c$) of the (001) surface. For the (001) samples with t=5-18 mm, the maximum magnetic levitation forces ($F_{max}s$) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.