• Journal of the Korean Society of Tobacco Science
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• v.3 no.2
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• pp.129-130
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• 1981

The potato tuberworm, Phthorimaea operculella, is an occasional pest to tobacco plants in southern regions of Korea. In order to screen effective pesticides against the worm in tobacco leaves, pot and field experiments were carried out in 1981. In the pot experiment with a tobacco variety, Hicks, several effective organic phosphates (Dimecron- LQ 50, Dursban-WP 25, Ekalux-EC 25. Elsan-EC 47.5, and EPN-EC 45), out of 9 Pesticides tested, were solecte4 from their high mortality of more than 90%. Among these Pesticides Ekalux- EC 25 and Elsan- EC 47.5 were recommended to tobacco growers from their excellent efficacy in the field experiment with a tobacco variety, Burley 21.

• Hwankyungkyoyuk
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• v.12 no.1
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• pp.99-109
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• 1999

Environment education, which is a principal solution to environmental problems in the world, is being practiced in Korea through the national curricula for primary and secondary schools. However, it hasn't been effective so far to practice environment education within those schools where a variety of subjects are taught. The purpose of this study is to look for the possibility of practicing environment education and thereby to make some suggestions for effective environment education in the field of English education, which doesn't seem to have a close relationship with environment education. This study first specified prospective contents of environment education by analyzing the Seventh National English Curriculum. Then, on the basis of them, the study explored how to practice environment education in the field of English education. Finally, for effective environment education, it made some suggestions and emphasized the importance of consistent efforts.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.628-632
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• 2016

We studied experimentally and theoretically the vertical range of the confined electric field in the gap area of metamaterials, which was analyzed for various gap widths using terahertz time-domain spectroscopy. We measured the resonant frequency as a function of the thickness of poly(methyl methacrylate) in the range 0 to 3.2 μm to quantify the effective detection volumes. We found that the effective vertical range of the metamaterial is determined by the size of the gap width. The vertical range was found to decrease as the gap width of the metamaterial decreases, whereas the sensitivity is enhanced as the gap width decreases due to the highly concentrated electric field. Our experimental findings are in good agreement with the finite-difference time-domain simulation results. Finally, a numerical expression was obtained for the vertical range as a function of the gap width. This expression is expected to be very useful for optimizing the sensing efficiency.

• Journal of the Optical Society of Korea
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• v.9 no.4
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• pp.140-144
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• 2005

In this paper we have investigated the guiding properties of photonic crystal fibers (PCFs) with a square-lattice of air-holes in the cladding. We have shown numerical results of PCFs with various air hole sizes and hole-to-hole spacings over a wide wavelength range. The group velocity dispersion, effective area and effective refractive index of PCF have been calculated numerically. The waveguide dispersion has greatly affected the group velocity dispersion when hole-to-hole spacing is about $1{\mu}m$. The effective area is quite flat over the wide spectral range whether the hole-to-hole spacing is large or ratio of diameter to pitch is large. From the field distribution, we found that the field is tightly confined within the core region of PCF when the pitch is $3{\mu}m$ and the air-filling fraction is 0.9.

• Current Optics and Photonics
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• v.2 no.6
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• pp.525-531
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• 2018

The effect of eccentricity on dispersion and nonlinear properties of a photonic crystal fiber having elliptical air holes is investigated using a fully vectorial effective index method. It is found that the effective refractive index increases with increase of eccentricity. The dependence of dispersion and nonlinear properties of the PCF on the eccentricity of the air hole is investigated. It is revealed that eccentricity of the air hole affects the zero dispersion wavelength. Further, the nonlinear properties such as mode field area, nonlinear coefficient and self phase modulation of the Photonic crystal fibers are analyzed. The mode field area increases and the nonlinear coefficient decreases with increase in eccentricity. The variation of the self phase modulation with elliptical air hole is also discussed.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.583-598
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• 2022

The Compaction effect is important for evaluating the subgrade construction. However, there is little research exploring the compaction quality of deep soil using hydraulic compaction. According to reinforcement effect analysis, dimensional analysis is adopted in this work to analyze subgrade compactness within the effective reinforcement depth, and a prediction model is obtained. A hydraulic compactor is then employed to carry out an in-situ reinforcement test on gravel soil subgrade, and the subgrade parameters before and after reinforcement are analyzed. Results show that a reinforcement difference exists inside the subgrade, and the effective reinforcement depth is defined as increasing compactness to 90% in the depth direction. Layered compactness within the effective reinforcement depth is expressed by parameters including the drop distance of the rammer, peak acceleration, tamping times, subgrade settlement, and properties of rammer and filler. Finally, a field test is conducted to verify the results.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.164-172
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• 2015

Background The use of a tourniquet in hand surgery is generally accepted as necessary to create a clear visualization of the operative field. This study aims to determine the effectiveness of one-per-million tumescent solution (1:1,000,000 epinephrine concentration) in creating a bloodless operative field in post-burn hand deformity surgeries performed without a tourniquet. Methods This retrospective observational study was conducted on a series of 12 patients with post-burn hand deformities who underwent surgery between February 2013 and January 2014. A total of 29 operative fields were recorded. The one-per-million tumescent solution was used for hemostatis instead of a tourniquet. The clarity of the operative field, volume of solution injected, duration of surgery, scar thickness and density, and functional outcomes at least three months after the surgery were observed. The relationship of scar thickness and density with the clarity of the operative field was analyzed with the chi-square test. Results Of the 29 operative fields in which the one-per-million tumescent technique was used, 48.2% were totally bloodless, 44.8% had minimal bleeding, and 6.9% had an acceptable level of bleeding. Both scar thickness and density were shown to have a significant relationship with operative field clarity (P<0.05). Conclusions The one-per-million tumescent technique is effective in facilitating post-burn hand deformity surgeries involving meticulous, multiple, and lengthy procedures by creating a relatively clear operative field without the use of a tourniquet. Although scar thickness and density are associated with the clarity of the operative field, this technique can be considered safe and effective in creating a clear operative field.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.3
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• pp.66-69
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• 2020

In ultra-low field magnetic resonance imaging (ULF-MRI), the strength of a static magnetic field can be comparable to that of gradient field. On that occasion, the gradient field is accompanied by concomitant gradient field, which yields distortion and blurring artifacts on MR images. Here, we focused on the distortion artifact and derived the equations capable of correcting it. Its usefulness was confirmed through the corrections in both simulated and experimental images. This solution will be effective for acquiring more accurate images in low and/or ultra-low magnetic fields.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.501-501
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• 2012

A 2.45 GHz electron cyclotron resonance (ECR) plasma source with a belt magnet assembly configuration (BMC) was developed for hyperthermal neutral beam (HNB) generation. A plasma source for high flux HNB generation should be satisfied with the requirements: low pressure operation, high density, and thin plasma. The ECR plasma source with BMC achieved high density at low operation pressure due to electron confinement enhancement caused by high mirror ratio and drifts in toroidal direction. The 2.45 GHz microwave launcher had a circularly bended WR340 waveguide with slits. The microwave E-field profile induced by the microwave launcher was studied in this paper. The E-field profile was a cups field perpendicular to B-filed at ECR zone. The optimized E-field profile and B-field were found for effective ECR heating.

• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.23-25
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• 1997

In this paper we will show theoretically that a refractive index grating exhibits a retro-self-focusing effect and an accompanying pinholing effect under the Gaussian intensity distribution of an incident optical field. Those effects result from an effective wave number change of the medium due to the intense optical field.