• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.44-52
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• 2020

This study was conducted to investigate the effect on Brain Quotient from inhalation of blended oils. The subjects of the study were 64 people aged 20 to 59 years, with 32 in the experimental group and 32 in the control group. Blended oil with six aromas (Lavender, Bergamot, Mandarin, Lemon, Cedarwood, Roman Chamomile) was given to the experimental group, and Jojoba oil was given to the control group, for 30 minutes. Before and after the experiment, BQ tests (SRQ, BRQ, ATQ, ACQ, EQ, ASQ, CQ, and BQ) from the experimental group and the control group were compared and analyzed using a brain-training machine (NeuroHarmony S). There was a significant difference between the experimental group and the control group in three out of the eight tests analyzed ATQ (p<.05), ACQ (p<.05), BQ (p<.05). In other words, aromatherapy improves concentration and memory by increasing attention, and helps to maintain mental activity, thinking ability, and behavioral balance. BQ also represents a comprehensive brain function, and aromatherapy is a good way to maintain human mental and physical health.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.310-317
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• 2013

This research has been carried out to evaluate the durability characterization of larch wood used for woody erosion control dam. Wood deterioration and strength properties were analyzed according to installed position and duration. Optical and scanning electron microscope were used for examining wood deterioration, and an universal testing machine was applied for compression and shearing strength. As a result, deposited wood in water was maintained almost similar anatomical and physical properties compare to normal wood, even though it was used for seven years. In non-deposited wood which was installed on the side of the dam, heartwood did not show any significant change during seven years, while sapwood was significantly deteriorated in five years. Also, strength properties of sapwood were significantly decreased according to installed duration whereas, degree of decrease in heartwood were relatively smaller than that in sapwood.

• Journal of Conservation Science
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• v.32 no.3
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• pp.377-384
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• 2016

There are physical and chemical method for removement of a lacquered layer existing on the surface when gilding an iron Buddha, these caused environmental pollution by surface degradation and is very noxious for conservation scientist's health. Thus, on this study, we conducted a lacquered layer removement experiments using Nd:YAG Laser which is contactless and eco-friendly. Specimens were made by polishing $5{\times}5$ size of iron(99.9%) specimens surfaces evenly and by differing of number of coating of unrefined lacquer, so there were thickness differences of $10{\mu}m$, $20{\mu}m$, and $30{\mu}m$. The laser machine used in this study was Nd:YAG Laser, and we used two wavelength modes; 1064 nm(160~180 mJ) for infrared light region and 532 nm(50~350 mJ) for ultraviolet light region. The experiment done by investigating the transition of specimens' surfaces with laser wavelength, energy, and numbers of investigation. The remain amount of lacquered layer surfaces before/after laser irradiation was investigated by stereoscopic microscope, observation by SEM, Non-contact Surface Roughness Measurement Device, and FT-IR etc. As a result of each analysis, we could verify the thickness of $10{\mu}m$, $20{\mu}m$ of lacquered layer removed without surface degradation when using 1064 nm wavelength with $1.0J/cm^2$ density. We could find out that Nd:YAG Laser is effective for removing remained lacquered layers when gilding an iron Buddha. In the future, when not only the metal has made various studies also wood lacquered furniture or the like, it seems to be utilized to remove the lacquer without surface damage.

• Journal of the Korean Wood Science and Technology
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• v.7 no.1
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• pp.8-11
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• 1979

The apparatus for measuring the static withdrawal resistance of nail is the AUTOGROPH S-500 static testing machine. The nails were 0.25 - 0.26 cm in diameter, 4.9-5.1cm in length, and were driven into wood for a depth of 3.0 cm. The physical properties of wood specimens are shown in table 1. Some data obtained in this experiment are as follows 1) The effects of the direction of driving and the time after driving upon static withdrawal resistance are shown in fig. 2-3. 2) The relations between static withdrawal resistance are moisture content of wood are characterized by nearly straight line as shown in fig. 4-5. The empirical formula areas follows: Y = -0.074 x + 12.73 (Pinus koraiensis Sieb & Zucc. - radial) Y = -0.073 x + 7.54 (Pinus koraiensis Sieb & Zucc. - longitudinal) Y = -0.061 x + 12.80 (Larix leptolesis Gord. - tangential) Y = -0.081 x + 7.61 (Larix leptolepsis Gord. - longitudinal) Where Y is the static withdrawal resistance ($kg{\cdot}cm$) and x is the moisture content(%).

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.35-43
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• 1973

Since automatic silk reeling machine has been used in the fold, silk reeling tension has been considered to be an important matter. Such silk reeling tension affects on the physical nature of silk which would be Wire Silk in case of super high reeling velocity. This will be a report regarding with the silk reeling tension used Korean cocoon and various analyses are carried out where reached to following results. 1. Korean silk is still far from Wire Silk yet produced as general silk. 2. There is more possibility to increase silk reeling velocity if cocoon nature is improved. 3. At present, it is considered that the optimum reeling velocity is to be about 190 r.p.m. which is corresponded with 0.4∼0.5 g/d silk reeling tension. 4. This report has prepared a silk reeling tension contolling diagram against reeling velocity as shown at Figure 7. The mathematical relations between them are; A. in case of total silk reeling tension; Y=5.0831＋0.0381X(Y; total reeling tension, g/21d, X; reeling velocity, m/min) B. in case of initial silk reeling tension; Y=3.1922＋0.0175X (Y; initial reeling tension, g/21d, X; reeling velocity, m/min) 5. The main problems for the increase of silk reeling velocity is considered to be Break Down of Silk Reeling Ends caused by Cocoon Jumping or Cocoon Layer Seperation during the silk reeling work. Such troubles are concerned with the produced cocoon nature.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.280-293
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• 2004

Statement of problem. Glass fiber post is one of recent developments to accommodate esthetic restoration for endodontically treated teeth. This has many advantages over conventional post system in physical properties, esthetic factor, risk of root and restoration fracture, adhesion to core, radiopacity, removal and retrievabilty, biocompatibility and chemical stability. Purpose. This in vitro study was to evaluate the most suitable type of resin core for the glass fiber post through surveying the fracture modes and the maximum load that fractures the tooth. Material and methods. 50 sound maxillary premolars restored with glass fiber posts($ParaPost^{(R)}$ Fiber White) and different types of resin cores(ParaCore, $Z100^{TM}$, $Rebilda^{(R)}$ and $Admira^{(R)}$) were prepared and loaded to faiure in a universal test machine. The maximum fracture load and fracture mode were investigated in the specimens that were restored with resin and those of metal cast and core. With the data, Wilcoxon rank sum test was used to validate the significance between the test groups, and Tukey' s studentized range test was used to check if there is any significant statistical difference between each test group. Every analysis was approved with 95% reliance. Results. On measuring the maximum fracture load of teeth specimens, there was a significant difference between the maximum fracture loads of the tooth specimens. ParaCore showed the highest mean maximum fracture load followed by $Z100^{TM}$. And, the distribution of fracture mode of tooth specimens showed generally Type D, the three parted fracture of the core around the post was mostly seen(62.5%), and specifically, ParaCore showed 90% and $Z100^{TM}$ showed 100% Type D fracture. Conclusion. Referring to the values of maximum fracture load and mean compressive fracture load, ParaCore and $Z100^{TM}$ had high values and are recommended as tooth colored resin core material for glass fiber post. CLINICAL IMPLICATIONS. This study was carried out intending to be of aid in selecting the appropriate resin core for the glass fiber post. The dual cure type composite resin ParaCore and light cure type composite resin $Z100^{TM}$ have good properties and are recommended as tooth colored resin core material for glass fiber post.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.268-279
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• 2011

Objective: The purpose of this study was to compare self-drilling orthodontic mini-implants of different surfaces, namely, machined (untreated), etched (acid-etched), RBM (treated with resorbable blasting media) and hybrid (RBM + machined), with respect to the following criteria: physical appearance of the surface, measurement of surface roughness, and insertion pattern. Methods: Self-drilling orthodontic mini-implants (Osstem implant, Seoul, Korea) with the abovementioned surfaces were obtained. Surface roughness was measured by using a scanning electron microscope and surface-roughness-testing machine, and torque patterns and vertical loadings were measured during continuous insertion of mini-implants into artificial bone (polyurethane foam) by using a torque tester of the driving-motor type (speed, 12 rpm). Results: The mini-implants with the RBM, hybrid, and acid-etched surfaces had slightly increased maximum insertion torque at the final stage ($p$ < 0.05). Implants with the RBM surface had the highest vertical load for insertion ($p$ < 0.05). Testing for surface roughness revealed that the implants with the RBM and hybrid surfaces had higher Ra values than the others ($p$ < 0.05). Scanning electron microscopy showed that the implants with the RBM surface had the roughest surface. Conclusions: Surface-treated, self-drilling orthodontic mini-implants may be clinically acceptable, if controlled appropriately.

• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.184-189
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• 2007

The importance of secondary battery industry is getting excited according to the development of battery industry as a high efficiency energy supplier of electronic machine of mobile information such as mobile phone, lap-top computer, PDA. It is rasing the interest about security of safety and high efficiency of cathode material for main part of secondary lithium battery. The cathode material which has been used like $LiCoO_2,\;LiMn_2O_4,\;LiNi_xCo_yMn_zO_2,\;LiNi_xCo_yM_zO_2$ (M=Al, Zr, Mg etc.,) the most typical material is $LiCoO_2$. But it is studying the development of substitute such as efficiency amelioration of $LiCoO_2$, thetiary element, olivine element because of the capacity of $LiCoO_2$, the matter of security; especially the betterment of efficiency, security research of safety has been actively processed in domestic and overseas about surface coating treatment of active cathode which is using oxide ($M_xO_3$). This study analyses side effect of battery according to increase of surface treatment, formation of precipitation for reagent condensation, non-reagent residue of oxide ($M_xO_3$) which is remains during the surface treatment of $LiCoO_2$; conducts study of new process, the consideration of the electrochemical property to improve oxide solution of mixing rate, mixture of surface treatment, dryness, calcinations conditionetc.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.49-53
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• 2018

Since various methods to form well-aligned nano-/micro- patterns are underlying technologies to fabricate next generation wearable electronic devices, many efforts have been made to realize finer patterns in recent years. Among lots of patterning methods, the present invention includes a nano-transfer printing (n-TP) process which is advantageous in that a processing cost is low and high-resolution patterns can be formed within a short processing time. We successfully achieved pattern formation of highly ordered Pt lines with line-width of 250 nm, 500 nm, and $1{\mu}m$ on transparent and flexible substrates. In addition, we analyzed the durability of the patterns, showing excellent stability of line-shape even after a physical and repeated bending test of 500 times using a bending machine. As a result, it is expected that a n-TP process is very useful for forming various metal patterns, and it is also expected to be applied to wiring and interconnection technology of next generation flexible electronic devices.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.1
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• pp.41-48
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• 2008

Enhanced machine reliability has dramatically reduced the rate and number of railway accidents but for further reduction human error should be considered together that accounts for about 20% of the accidents. Therefore, the objective of this study was to suggest a new taxonomy of performance shaping factors (PSFs) that could be utilized to identify the causes of a human error associated with railway accidents. Four categories of human factor, task factor, environment factor, and organization factor and 14 sub-categories of physical state, psychological state, knowledge/experience/ability, information/communication, regulation/procedure, specific character of task, infrastructure, device/MMI, working environment, external environment, education, direction/management, system/atmosphere, and welfare/opportunity along with 131 specific factors was suggested by carefully reviewing 8 representative published taxonomy of Casualty Analysis Methodology for Maritime Operations (CASMET), Cognitive Reliability and Error Analysis Method (CREAM), Human Factors Analysis and Classification System (HFACS), Integrated Safety Investigation Methodology (ISIM), Korea-Human Performance Enhancement System (K-HPES), Rail safety and Standards Board (RSSB), $TapRoot^{(R)}$, and Technique for Retrospective and Predictive Analysis of Cognitive Errors (TRACEr). Then these were applied to the case of the railway accident occurred between Komo and Kyungsan stations in 2003 for verification. Both cause decision chart and why-because tree were developed and modified to aid the analyst to find causal factors from the suggested taxonomy. The taxonomy was well suited so that eight causes were found to explain the driver's error in the accident. The taxonomy of PSFs suggested in this study could cover from latent factors to direct causes of human errors related with railway accidents with systematic categorization.