• Journal of the Korea Convergence Society
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• v.12 no.12
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• pp.563-572
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• 2021

This study conducted a network meta-analysis to compare the effectiveness and ranking of pressure ulcer preventive programs in intensive care units. A frequency network meta-analysis was performed to identify evidence from relevant randomized control trials. A total of 10 randomized control trials involving 5 intervention subgroups were included in this study. Based on the ranking probabilities(P-Score), preventive materials was ranked as the most effective among all programs (P-Score 85.3.%: OR=0.12, 95% CI: 0.03, 0.49). Next was silicone foam dressing(P-Score 84.5%: OR=0.14, 95% CI: 0.05, 0.38), care bundle(P-Score 60.0%: OR=0.29, 95% CI: 0.07, 1.25), reposition (P-Score 32.3%: OR=0.66, 95% CI: 0.21, 2.09) and synthetic fabrics (P-Score 23.8%: OR=0.85, 95% CI: 0.20, 3.65). It is necessary to develop practical and efficient interventions that can prevent pressure ulcers in intensive care unit patients, improve patient safety, and reduce nurses' workload.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.257-267
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• 2023

Purpose. The purpose of the study was to fabricate a prototype robotic simulator for dental education, to test whether it could simulate mandibular movements, and to assess the possibility of the stimulator responding to stimuli during dental practice. Materials and methods. A virtual simulator model was developed based on segmentation of the hard tissues using cone-beam computed tomography (CBCT) data. The simulator frame was 3D printed using polylactic acid (PLA) material, and dentiforms and silicone face skin were also inserted. Servo actuators were used to control the movements of the simulator, and the simulator's response to dental stimuli was created by pressure and water level sensors. A water level test was performed to determine the specific threshold of the water level sensor. The mandibular movements and mandibular range of motion of the simulator were tested through computer simulation and the actual model. Results. The prototype robotic simulator consisted of an operational unit, an upper body with an electric device, a head with a temporomandibular joint (TMJ) and dentiforms. The TMJ of the simulator was capable of driving two degrees of freedom, implementing rotational and translational movements. In the water level test, the specific threshold of the water level sensor was 10.35 ml. The mandibular range of motion of the simulator was 50 mm in both computer simulation and the actual model. Conclusion. Although further advancements are still required to improve its efficiency and stability, the upper-body prototype simulator has the potential to be useful in dental practice education.

• Science of Emotion and Sensibility
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• v.20 no.2
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• pp.171-178
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• 2017

'Smart Sensibility Mat (SSM)' was developed and manufactured for positive sensibility of newborn with fiber, digital, and sensibility technology to reflect features and advantages of kangaroo care. For tactile stimuli, the tube of the silicon material to provide a constant temperature of $32^{\circ}C$ was inserted into the mat and connected to the water-thermostat. To provide a uniform temperature throughout the mat, the fabric by the inserting conductive yarn was attached to the mat surface. After wrapping the mat with cotton pad, the polyurethane foam used as medicine in order to similar to the human skin was bonded to the surface of the mat. To provide the auditory stimuli of a level of 30dB with mother's heartbeat sounds and voice recorded in advance, the Bluetooth speaker was inserted into the mat. To investigate the effects of SSM, 10 newborns who born within two weeks were involved in this experiment. While the baby was lying on each of the general mat (GM) and SSM, the baby's physiological signals-heart rate, breathing rate, temperature- were measured and then, those were conducted t-test to examine the difference between the signals of SSM and GM. The results were as follows: heart rate (t=8.131, p<.001) and respiratory rate (t=7.227, p<.001) among the physiological signals of SSM decreased significantly than GM within the normal range. Temperature (t=1.062, p=0.292) at SSM showed a tendency to decrease than GM within the normal range. This means the tactile stimuli and the auditory stimuli providing from SSM give stable physiological responses. Thus, SSM leads to have psychological comfort and stability of newborns.

• Composites Research
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• v.12 no.3
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• pp.8-16
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• 1999

Carbon woven fabric/C/SiC composites were fabricated by multiple impregnations of carbon woven fabric/carbon preform with the polymer precursor of SiC, i.e., polycarbosilane. In addition, two kinds of low density carbon/carbon preforms which had different fiber volume fraction and fiber orientation, i.e., a carbon woven fabric(${\thickapprox}$55 vol%)/carbon and a chopped carbon fiber${\thickapprox}$40 vol%)/carbon composites, were reaction-bonded with a silicon melt at 1$700^{\circ}C$ in a vacuum to fabricate dense carbon fiber/Si/SiC composites. The reaction-bonding process increased the density to ~2.1 g/$cm^3$ from 1.6 g/$cm^3$ and 1.15 g/$cm^3$ of a carbon woven and a chopped carbon preforms, respectively. All of the composites fractured with extensive fiber pull-out. The higher the density the higher the stiffness and proportional limit stress. The mechanical properties obtained from a three-point bend and tension tests were compared. The ratios of the peak tensile stresses to the bending strengths of a carbon woven and a chopped carbon composites were about one-third, respectively. The carbon woven fabric/Si/SiC composites with density of 2.06 g/$cm^3$ showed ~120 MPa of ultimate strength and ~80 MPa of proportional limit in bend testing.

• Investigative Magnetic Resonance Imaging
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• v.9 no.2
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• pp.134-139
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• 2005

Purpose : To evaluate the usefulness of acoustic noise attenuator on auditory fMRI examination. Materials and methods : The acoustic noise attenuator consists of mask, earmuff and silicon earplug. The soft polyurethane sheet and polyurethane form , which has a good soundproof characteristic were used for mask and earmuff. Auditory fMRI experiments of 500 Hz pure tone stimulation were performed in three different cases; first all of mask, earmuff and earplug, secondly earmuff and earplug only and finally without attenuator in 4 normal hearing volunteers. For data acquisition, BOLD MR imaging technique was employed at a 1.5T MR scanner equipped with high performance gradient system. The raw data were analyzed using a SPM-99 analysis software and the activation maps were obtained. Results : In case of all items of acoustic attenuator used, the results revealed that activation was focused on primary auditory area. When only earmuff and earplug were used, the results showed that the activation spread over primary auditory and secondary associative areas. Last, when no device used, only weak activation was observed on the right auditory cortex. Conclusion : It is expected that the acoustic noise attenuator, which consists of earplugs, earmuffs and mask, is a very useful device in auditory fMRI study.

• Polymer(Korea)
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• v.39 no.2
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• pp.210-218
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• 2015

The reaction behavior of rigid polyurethane foams were studied on the effects of gelling catalysts of amine type, such as; dimethylcyclohexyl amine (DMCHA) and of potassium type, such as; potassium octoate (PO). Rigid polyurethane foams were provided with polymeric 4,4'-diphenylmethane diisocyanate, polyester polyol, silicone surfactant, blowing agent and a few gelling catalysts. As the contents of catalyst, DMCHA increased from 0 to 2.0 g, the reaction time decreased from ca. 330 to ca. 35 sec and due to the exothermic reaction, the maximum temperature increased from ca. 217 to ca. $234^{\circ}C$, respectively. As the contents of PO increased from 0 to 2.5 g, the reaction time decreased from ca. 79 to ca. 38 sec and the maximum temperature increased from ca. 182 to ca. $271^{\circ}C$, respectively. The kinetic parameters were calculated and the conversions were based on the temperature rising method of adiabatic process. As the content of DMCHA increased, the rate constant $k_0$ increased. But in the case of PO catalyst, $k_0$ did hardly depend upon its amount, and showed us similar reaction rate constants.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.