• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.438-439
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• 2011

Magnetic levitation control system of a metal ball was designed using combined PID and fuzzy logic, in which two electromagnets are used to control the vertical and horizontal position of the ball. Single synchronization coil sensor was used to detect the vertical position. Electric power is differentially supplied to two electromagnets so that the ball can move horizontally. In the experiment 25 cm diameter metal ball was levitated and successfully controlled to move horizontally.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.54-62
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• 2000

The purpose of this study is to bring out the optimal design factors which effect on dynamic characteristics in the design of flow control servo valve with high response characteristics, and to verify the validity of the design factors. In this study, force feedback type flow control valve with nozzle/flapper and with no drain is studied. And, the effect of the parameters, such as fixed orifice, nozzle diameter, and maximum displacement between nozzle and flapper are analyzed. We have done simulations using the optimal design factors and simulink(Matlab) as a simulation tool, and verified the validity of our simulations by means of comparison our simulation results with an experimental results of another similar valve.

• Journal of Ginseng Research
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• v.16 no.2
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• pp.146-150
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• 1992

Life history, ginseng damage, and chemical control of the snail Acusta despecta sieboldiana Pfeiffer were investigated in the field and laboratory conditions from 1987 to 1990. Eggs of the snail were whitish globular and 1.,93${\pm}$ 0.09 mm in diameter which were deposited as egg mass composed of 28.4${\pm}$ 15.4 eggs. Egg period was 11.8${\pm}$ 1.6 days under the laboratory condition. Most eggs were laid during mid July in the field. The snail had a life cycle of a year and hibernated from November to April. Significant ginseng damages by the snail (over 10% to the total number of plants) were observed only in the three to five year old ginseng fields with rice straw mulching. Based on the dates that the first ginseng damages were observed and on the questionary examination, ginseng damages seemed to occur from May to July. Metaldehyde (6%) bait showed reliable control effects on the snail.

• Physical Therapy Korea
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• v.7 no.3
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• pp.34-48
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• 2000

The purpose of this study was to determine the effects of mild-intensity exercise training on the denervated muscle atrophy in the sciatic nerve injured rat. Thirty-six male Sprague-Dawley rats (250~300 g) were randomly assigned into three groups; sham-denervated group (n=8), denervated group (n=8), and denervated-exercised group (n=20). Exercise consisted of treadmill running at 20 m/min speed with 0% grade for 30 min/day. The animals were decapitated at the second and sixth weeks postcrush. Soleus and medial gastrocnemius were immediately excised to be weighed. Type I and II fibers of the muscles were differentiated by m-ATPase (pH 9.4) stain, and fiber diameters were evaluated. The results were as follows: 1) The weight of the soleus and medial gastrocnemius muscles showed a tendency to increase in both the denervation-exercised groups compared to the denervated group. 2) In the 2-week denervation-exercised group, type II fiber diameter of soleus and type I fiber diameter of medial gastrocnemius were increased significantly compared to the denervated control group. 3) In the 6-week denervated-exercised group, type I fiber diameter of soleus and type II fiber diameter of medial gastrocnemius were hypertrophied significantly compared to sham-denervated group. The results of this study suggested that treadmill exercise partially prevented denervation atrophy in the soleus and medial gastrocnemius of the rat.

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.43-48
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• 2020

It is considered that most of reusable pipe supports, which are used as formwork support posting at construction sites, do not meet the performance standard. Due to the use of reusable pipe supports that do not meet such performance standard the potential risk of collapse accident is increasing. Therefore, this study identifies the status of compliance with performance standard, and presents the requirements for improving quality control to prevent the collapse of pipe supports reused at the construction site. First, if the female thread of the product with no clearance and new support pin with the diameter of 12mm are replaced at the same time for use, it is considered that the performance will be improved. Second, as the quality performance during use can be improved in the case of larger thickness of inner diameter compared to the case of larger thickness of outer diameter, it is necessary to increase the inner pipe thickness greatly than the current thickness. Based on the results of this study, it is expected that the performance the reusable pipe support (V4) can be improved, if the diameter of the support pin is 12mm, the female thread has a small clearance, and the inner tube thickness is 2.3 ~ 2.7mm. In addition, it is considered that other performance improvement factors included in the study results could be used as important data for improving the performance of reusable pipe support.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8447-8450
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• 2014

Background: To evaluate factors for predicting the granulosa cell tumor of the ovary (GCTO) pre-operatively. Materials and Methods: This retrospective designed study was conducted on 34 women with GCTO as the study group and 76 women with benign ovarian cysts as the control group. Data were recorded from the hospital database and included age, body mass index (BMI), parity, serum estradiol ($E_2$) levels, diameter of the mass, ultrasonographic features, serum CA125 level, risk of malignancy index (RMI), duration of menopause, postoperative histopathology result, and the neutrophil/lymphocyte ratio (NLR). Results: The demographic parameters showed no statistically significant difference between the groups. Preoperative diameter of the mass, CA125, duration of menopause, and neutrophil/lymphocyte ratio were significantly different between the groups. ROC curve analysis demonstrated that diameter of the mass, serum estradiol and Ca125 levels, RMI and NLR may be discriminative factors in predicting GCTO preoperatively. Conclusions: In conclusion, we think that a careful preoperative workshop including diameter of the mass, serum estradiol ($E_2$) and Ca125 levels, RMI and NLR may predict GCTO and may prevent incomplete approaches.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.599-606
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• 2010

In the present study, actuators with diaphragms of different thickness and chambers of different diameter are fabricated to examine experimentally how the behavior characteristics of the actuator diaphragm in a thermopneumatic micropump are affected by diaphragm thickness and chamber diameter under various operating conditions with different values of input voltage and frequency. The actuator comprises a microheater set on Pyrex glass, a chamber, and a diaphragm. For all values of the input energy, as the frequency decreases below 10 Hz, the maximum center deflection of the diaphragm greatly increases irrespective of diaphragm thickness and chamber diameter. At low frequencies, as the heat energy supplied to the chamber increases, the center of deflection of the diaphragm increases; the magnitude of deflection is high for thin diaphragms and for diaphragms whose chambers have small diameters. At frequencies higher than 10 Hz, all the design variables such as diaphragm thickness, chamber diameter, and the input energy have negligible effect on the center deflection of the diaphragm.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.119-130
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• 2010

Pulmonary toxicity of talc containing tremolite asbestos (TCT) has been studied in term sequential in Sprague-Dawely rats. UICC chrysotile(average diameter 0.03${\mu}m$, average length 2.93${\mu}m$) was applied as the positive control. TCT was analyzed for its physicochemical properties by transmission electron microscope equipped with energy dispersive X-ray spectrometer(TEM-EDS). The effects of 2mg TCT(talc average diameter 9.7${\pm}$8.4${\mu}m$; tremolite average diameter 1.6${\pm}$1.6${\mu}m$, average length 10.8${\pm}$7.0${\mu}m$) on pathological changes were evaluated after 1, 8 weeks instilled into rat lungs. 2mg Chrysotile continuously affected lung pathological changes. Inflammation and granuloma response broke out from 1 week after instilled with chrysotile and the pathological examination further showed increased legions of lung after 8 weeks. But TCT did not showed lung pathological changes. The biopersistence of TCT and chrysotile was evaluated by TEM- EDS. Whereas chrysotile continuously have retained to 8 weeks instilled into rat lungs, talc of TCT showed statistically significant decrease of diameter from 1 weeks and statistically significant change in Si atomic % compositions at 8 weeks instilled into rat lungs. Physicochemical properties of tremolite of TCT were not affected until 8 weeks instilled into rat lungs. This study showed that the durability of TCT in the lungs is much weaker than chrysotile.

• Transactions of Materials Processing
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• v.23 no.8
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• pp.489-494
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• 2014

Micro forming is an appropriate process to manufacture very small metal parts which can be employed in the field of electronic devices or electrically controlled mechanical systems. The purpose of the current study was to investigate the influences of both blankholding force and blank diameter for the deep drawing of very small cups. It is essential to control the blankholding force because improper force can result in defects such as wrinkles in the flange or cracks in the corner of the drawn cups. In the current study blankholding force was controlled by springs connected to the blankholder of a press die. Exchangeable bushing dies with various die-corner radii were also used. To obtain the limit drawing ratio for each working condition several sizes of circular specimens were prepared using blanking tools. Beryllium copper(C1720) alloy sheet of $50{\mu}m$ thickness was chosen for the experiments. The maximum limit drawing ratio of 2.1 was achieved experimentally for the conditions of the blankholder force(BHF)=5.3kgf and Rd=0.3mm. Both thickness and hardness along the central section of drawn cups were measured and compared for different drawing conditions. It was found that the deviation of measured data in the thickness and hardness distribution increases with increasing blankholder force and blank diameter.

• Mycobiology
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• v.48 no.5
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• pp.383-391
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• 2020

Use of nanoparticles (NPs) in several commercial products has led to emergence of novel contaminants of air, soil and water bodies. The NPs may exhibit greater ecotoxicity due to nano-scale dependent properties over their bulk counterparts. The present investigation explores the effect of in vitro supplementation of TiO₂, silica and silver NPs on radial growth and ultrastructural changes in the hyphae and spores of two mushroom genera, Ganoderma lucidum and Volvariella volvaceae. A concentration dependent decrease in radial growth on NP amended potato dextrose agar medium was recorded. However, in comparison to control, there was decrease in radial diameter on supplementation with TiO₂ NPs while an increase was recorded for silica and silver NPs amendments as compared to their bulk salts at same concentrations after 48 h of incubation. Optical microscopy studies showed decrease in the number of spores while increase in spore diameter and thinning of hyphal diameter on NPs supplementation. Scanning electron microscopy analysis of fungal growth showed presence of deflated and oblong spores in two fruiting strains of Ganoderma while Volvariella exhibited decreased sporulation. Further, hyphal thinning and branching was recorded in response to NP amendments in both the test mushrooms. Enhancement of protein content was observed on NP compared to bulk supplementation for all cultures, concentrations and hours of incubation except for TiO₂ NPs. Likewise, bulk and NP supplementations (at 100 mg L^-1) resulted in enhanced laccase activity with occurrence of laccase specific protein bands on SDS-PAGE analysis.