• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.4
• /
• pp.319-323
• /
• 1991

To determine how closely related to field lodging for several characters affecting the field lodging for several characters affecting field lodging, and to obtain the basic information for selection of lodging resistance genotype, an experiment was conducted with 10 varieties from May to Oct., 1990 at the experimental field in Sunchon Xational University. Culm length, dry weight per unit culm length (W/1), bending moment per unit culm diameter (W1/d), lodging index (L), bending load ratio (W1/P), and index of critical lodging load(W$_{s}$$^{2}$/1$^4$) were the most closely related characters to field lodging. Culm length showed highly significant positive correlation coefficient with field lodging(r=0.7607), but it may be undesirable to judge lodging resistance of genotype by culm length itself without consideration of culm stiffness. Considering the difficulty and time-consuming to measure the character, clum length, W/1, W1/d, and W$_{s}$$^{2}$/1$^4$ were easy to measure and hence would be the most useful variables to judge the lodging resistance of genotype. Culm diameter, cross sectional area of culm, thickness of culm wall, and the second inertia moment of cross section of culm were not correlated with field lodging at all. Breaking strength of culm showed significantly negative correlation coefficient (r=-0.3986) with field lodging.ing.

• Applied Chemistry for Engineering
• /
• v.27 no.6
• /
• pp.577-582
• /
• 2016

In this study, we compared and analyzed the flame retardancy and mechanical properties of three different rigid polyurethane foams (RPUF) containing noble non-halogen phosphorus flame retardant (BHP-RPUF) or halogen-phosphorus flame retardant (TCPP-RPUF) or no flame retardant material (Pure-RPUF). The noble phosphorus-based flame retardant, bis(3-(3-hydroxypropoxy)propyl) phenyl phosphate (BHP), was synthesized by the reaction between disodium phenyl phosphate and 3-chloro-1-propanol. Through universal testing machine (UTM) experiments, the compressive strength of BHP-RPUF was similar to that of TCPP-RPUF. From the result of foam morphology analysis, it was confirmed that BHP-RPUF has the lowest thermal conductivity of $0.023W/m{\cdot}K$. We also measured the size of air bubbles using reaction velocity and SEM, and analyzed how they affect the thermal conductivity. In addition, the heat-resisting property was investigated through TGA analysis. The limited oxygen index (LOI) test confirmed that BHP had the ability to increase the flame retardancy of RPUF.

• Applied Chemistry for Engineering
• /
• v.7 no.3
• /
• pp.424-432
• /
• 1996

The fiber reinforced thermoplastic composites(FRTP) were prepared with polypropylene fiber(PPF) as matrix and vinylon(VF), Aramid(KF) or nylon fiber(PAF) as reinforcing materials using the integrated fiber mixing apparatus. The composite sheets were prepared by compression molding and their impact and morphological properties were characterized. VF/PP system showed the maximum value in Izod impact strength, while KF/PP system showed the maximum value in high rate impact properties. Ductility Index(DI) order was VF/PP>KF/PP>PAF/PP. A maximum DI for VF/PP, 2.43, was obtained when the weight fraction of VF was 20%. The optimum amount of the reinforcing organic fiber was found to be 20~30%. As a result, it is concluded that VF/PP system has better interfacial adhesion properties than either KF/PP or PAF/PP.

• Korean Journal of Food Science and Technology
• /
• v.20 no.4
• /
• pp.470-475
• /
• 1988

The extrusion-cooking method was used to make gelatinized rice extrudate from rice grits of the Chuchung and the Samgang varieties. The water contents of raw rice grits varied from 15% to 25%, and the physicochemical properties of extrudates were evaluated. Low moisture content showed high expansion ratio in rice extrudate and resulted in some decrease in gelatinization, bulk density and break strength. Increasing the water content to 25% resulted in increase in water absoption index but decrease in water solubility index. With regards to Brabender Amylograph values and rheological patterns, higher moisture content in raw materials revealed stronger pseudoplastic flow behavior with lower viscogram property. Hunter's color values of rice flours extruded at low water content were low in b values. Scanning electron microscopy demonstrated the break-down of starch granules during extrusion.

• Journal of The Korean Astronomical Society
• /
• v.48 no.2
• /
• pp.155-164
• /
• 2015

In Kang (2015) we calculated the acceleration of cosmic-ray electrons at weak spherical shocks that are expected to form in the cluster outskirts, and estimated the diffuse synchrotron radiation emitted by those electrons. There we demonstrated that, at decelerating spherical shocks, the volume integrated spectra of both electrons and radiation deviate significantly from the test-particle power-laws predicted for constant planar shocks, because the shock compression ratio and the flux of inject electrons decrease in time. In this study, we consider spherical blast waves propagating through a constant density core surrounded by an isothermal halo with ρ ∝ r⁻ⁿ in order to explore how the deceleration of the shock affects the radio emission from accelerated electrons. The surface brightness profile and the volumeintegrated radio spectrum of the model shocks are calculated by assuming a ribbon-like shock surface on a spherical shell and the associated downstream region of relativistic electrons. If the postshock magnetic field strength is about 0.7 or 7 µG, at the shock age of ∼ 50 Myr, the volume-integrated radio spectrum steepens gradually with the spectral index from α_inj to α_inj + 0.5 over 0.1–10 GHz, where α_inj is the injection index at the shock position expected from the diffusive shock acceleration theory. Such gradual steepening could explain the curved radio spectrum of the radio relic in cluster A2266, which was interpreted as a broken power-law by Trasatti et al. (2015), if the relic shock is young enough so that the break frequency is around 1 GHz.

• Journal of Periodontal and Implant Science
• /
• v.50 no.4
• /
• pp.251-259
• /
• 2020

Purpose: This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. Methods: This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the Löe-Silness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. Results: There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). Conclusions: This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.

• The Research Journal of the Costume Culture
• /
• v.10 no.6
• /
• pp.735-747
• /
• 2002

This study aimed at investigating the change of fat in each body part according to the wearing of sport underwear made of specially-processed materials. in this study. 6 females made up of three early twenties, and three later thirties took part in the exercises for 12 weeks to to out the change of fat amount in body, square of body part by CT and obesity after and before an exercise. The results are as follows: In the obesity condition after and before an exercise, Roller's index shows that in case of 51 and 54, one level was lowered concerning the basic physical strength and optimal index was not changed. In the silhouette between body frames. there are differences between ages. The body fat rate decreased 35.95% on the average. and the amount of the body fat of females in twenties was more than that in thirties. The amount of body fat decrease with the lapse of exercising time, while the amount of body fat shows increased of 0.75%, which showed the minus correlation. The rate of averaged flat by CT went up after an exercise in every body part. and also the decreased value of subcutaneous fat was not proportioned to that of weight and girth. Inbody parts, the lower abdomen was shown 49.7%, navel part 47.7% and waist part 37.3% each in numerical value. In the thickness of subcutaneous fat concerning waist, the value of front-center line was the lowest, and followed by rear-center line and lateral line. 1204degree part in the navel showed the most fat layed, and the lowest fat layed was in the lateral part. Concerning the lower part of abdomen, under-skin fat was the most layed in 120degree part like that of navel part.

• Structural Engineering and Mechanics
• /
• v.76 no.3
• /
• pp.421-433
• /
• 2020

Masonry infills are normally considered as non-structural elements in design practice, therefore, the interaction between the bounding frame and the strength contribution of masonry infills is commonly ignored in the seismic analysis work of the RC frames. However, a number of typical RC frames with irregular distributed masonry infills have suffered from undesirable weak-story failure in major earthquakes, which indicates that ignoring the influence of masonry infills may cause great seismic collapse risk of RC frames. This paper presented the investigation on the risk of seismic collapse of RC frames with irregularly distributed masonry infills through a large number of nonlinear time history analyses (NTHAs). Based on the results of NTHAs, seismic fragility curves were developed for RC frames with various distribution patterns of masonry infills. It was found that the existence of masonry infills generally reduces the collapse risk of the RC frames under both frequent happened and very strong earthquakes, however, the severe irregular distribution of masonry infills, such as open ground story scenario, results in great risk of forming a weak story failure. The strong-column weak-beam (SCWB) ratio has been widely adopted in major seismic design codes to control the potential of weak story failures, where a SCWB ratio value about 1.2 is generally accepted as the lower limit. In this study, the effect of SCWB ratio on inter-story drift distribution was also parametrically investigated. It showed that improving the SCWB ratio of the RC frames with irregularly distributed masonry infills can reduce inter-story drift concentration index under earthquakes, therefore, prevent weak story failures. To achieve the same drift concentration index limit of the bare RC frame with SCWB ratio of about 1.2, which is specified in ACI318-14, the SCWB ratio of masonry-infilled RC frames should be no less than 1.5. For the open ground story scenario, this value can be as high as 1.8.

• Korean Journal of Metals and Materials
• /
• v.50 no.11
• /
• pp.847-854
• /
• 2012

Al-doped ZnO (AZO) thin films were grown on quartz substrates by the sol-gel method. The effects of the Al mole fraction on the structural and optical properties of the AZO thin films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-VIS spectroscopy. The particle size of the AZO thin films decreased with an increase in Al concentrations. The optical parameters, the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity, were studied in order to investigate the effects of Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at an infinite wavelength of the AZO thin films were affected by the Al incorporation. The optical conductivity of the AZO thin films also increased with increasing photon energy.

• Journal of International Academy of Physical Therapy Research
• /
• v.9 no.4
• /
• pp.1683-1686
• /
• 2018

Low back pain (LBP) is the most common reason for seeking physical therapy (PT) care. Recent studies suggest that axial loading can have a positive impact on the intervertebral disc by improving its tensile strength. Further, whole body vibration (WBV) appears to improve spinal muscle relaxation. Therefore, this case study describes the use of axial loading using a mini-trampoline in a female with chronic LBP. This case report is a single subject design. This patient is a 29-year-old female with a six-month history of low back pain following a motor vehicle accident. MRI found herniated discs at L4 and L5, clinical tests were positive for pain in the L4 and L5 dermatome and myotome the slump test was positive for neural tension, and LBP was constant at 4-6/10 over the past four months. She received axial loading exercises using a mini-trampoline and performed six sessions that were, scheduled twice a week for three weeks. Her Oswestry Disability Index (ODI) score improved from 40% at the time of her first visit to 22% at her final visit. Pain measure on the Numeric Pain Rating Scale (NPRS) after the first treatment was 7/10, and her pain after the final treatment was 0/10. These changes in the pain scores are clinically significant and exceed the minimal clinically important difference (MCID). This patient had a significant improvement in her pain using the NPRS and the ODI. This case study suggests that axial loading may be an effective treatment for some individuals with discogenic chronic low back pain.