• Therapeutic Science for Rehabilitation
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• v.3 no.2
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• pp.83-89
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• 2014

Objective : This study aims to investigate the effect of half- eyes patching for the reduction of unilateral neglect of left-side hemiplegia. Methods : This study used the ABA design. He was required to wear the half- eyes patching during all the period of ADL because unilateral neglect causes many problems in the majority of ADL. The assessments for the unilateral neglect had been performed by the Line bisection and the Albert test once a session (day). Results : Regarding the Means of the errors to the Line bisection and the Albert test, the Means of the errors was not decreased during the period of the intervention (B) and was not decreased after the withdrawal (A'). Conclusions : Half-eyes patching was non-effective to r e lease the unilateral neglect. Further study is necessary to increase the sample size and the duration of experiments.

• Korean Journal of Ichthyology
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• v.30 no.3
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• pp.155-160
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• 2018

The distribution aspect and extinction threat evaluation of the endangered species, Cottus hangiongensis were investigated from 2011 to 2017 in Korea for this study. The distribution reports of C. hangiongensis were divided into 1954~1985, 1981~2003, 2004~2012, and 2011~2017. The number of habited streams decreased gradually to 30, 24, 10, and 19 streams, respectively. In this study (2011~2017), C. hangiongensis was newly found in two streams (Ayajincheon and Chuksancheon), but 15 streams that appeared in the past are not in this study. The main habitat of C. hangiongensis was the downstream riffle of clean water with fast velocity and cobble-boulder bottoms. Given this evidence as noted for more than a 30% reduction in population after 2003, due to construction wear, river work and the qualitative decline of the habitat, C. hangiongensis is now considered to be Vulnerable (VU A2ac) based on the IUCN Red List categories and criteria.

• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.543-549
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• 2021

Aluminum cast iron has excellent oxidation resistance and good resistance to sulfide and corrosion. Compared to Ti and Ni alloys, it is expected to be a substitute material for structural materials and stainless steels because it is relatively inexpensive to use Fe, which is a non-strategic element. This results in a weight reduction effect of about 30% as compared to the use of stainless steel. With regard to aluminum as an alloying material, it is an element that has been widely used for the alloying of cast iron in recent years. Practical use has been delayed owing to the resulting lack of ductility at room temperature and the sharp decrease in the strength above 600℃ of this alloy, however. The cause of the weak room temperature ductility is known to be environmental embrittlement by hydrogen, and the addition of various alloying elements has been attempted in order to mitigate these shortcomings. Although alloying elements such as vanadium, chromium, and manganese are mainly used to increase the hardness and wear resistance of gray cast iron, the price of finished products containing these elements and the problems associated with alloys with this material impose many limitations.

• Tribology and Lubricants
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• v.35 no.5
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• pp.274-285
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• 2019

Chemical mechanical polishing (CMP), which is a material removal process involving chemical surface reactions and mechanical abrasive action, is an essential manufacturing process for obtaining high-quality semiconductor surfaces with ultrahigh precision features. Recent rapid growth in the industries of digital devices and semiconductors has accelerated the demands for processing of various substrate and film materials. In addition, to solve many issues and challenges related to high integration such as micro-defects, non-uniformity, and post-process cleaning, it has become increasingly necessary to approach and understand the processing mechanisms for various substrate materials and abrasive particle behaviors from a tribological point of view. Based on these backgrounds, we review recent CMP R&D trends in this study. We examine experimental and analytical studies with a focus on substrate materials and abrasive particles. For the reduction of micro-scratch generation, understanding the correlation between friction and the generation mechanism by abrasive particle behaviors is critical. Furthermore, the contact stiffness at the wafer-particle (slurry)-pad interface should be carefully considered. Regarding substrate materials, recent research trends and technologies have been introduced that focus on sapphire (${\alpha}$-alumina, $Al_2O_3$), silicon carbide (SiC), and gallium nitride (GaN), which are used for organic light emitting devices. High-speed processing technology that does not generate surface defects should be developed for low-cost production of various substrates. For this purpose, effective methods for reducing and removing surface residues and deformed layers should be explored through tribological approaches. Finally, we present future challenges and issues related to the CMP process from a tribological perspective.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.146-153
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• 2001

The difference of composition of composite resin may affect the mechanical properties of composite resin and the environment is important for the properties of materials. The composite resin restoration is always exposed to fluid in oral cavity and the composite resin matrix is able to absorb water, which is accompanied by some swelling of the composite The uptake of water by composites has been correlated with decreases in surface hardness and wear resistance. The purpose of this study was to investigate the effects of water storage in $37^{\circ}C$ distilled water after 7days, 30days, 60days, 120days on compressive strength and flexural strength of dental composite resin, Z-100(group 1) Spectrum(group 2), Clearfil AP-X(group 3), Pyramid(group 4), Heliomolar(group 5). The compressive and flexural strength were measured by instron machine. The following results were obtained: 1. There were significant reduction of compressive strength as water storage time increased, 7days, 30days, 60 days, 120days(p<0.05). 2. There were significant reduction of flexural strength as water storage time increased, 7days, 30days, 60days, 120days(p<0.05). 3. Group 1, 2, 3 -hybrid type showed higher compressive and flexural strength than group 5-microfine type which had lower filler contents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.797-803
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• 2019

This study was carried out to reduce the lateral vibration of high-speed electric multiple units. In the study, the high-speed electric multiple unit prototype (HEMU-430X) has a high lateral vibration at low equivalent conicity regardless of the wheel profiles (XP55, GV40, S1002). As wheel wear progresses and the equivalent conicity increases, the lateral vibration tends to decrease. The reason is that a combination of the suspension characteristics causes the body and bogie to resonate at a frequency of 1.4 Hz when the equivalent conicity is low, resulting in body hunting. An investigation of the lateral vibration of overseas high-speed trains showed that a decrease in the hydraulic stiffness of the yaw damper could improve the vibration. The series stiffness of the yaw damper is a combination of the hydraulic stiffness and elastic joint. In this study, an attempt was made to improve the lateral vibration by lowering the stiffness of the elastic joint. The series stiffness of the adjusted yaw damper was approximately 60% compared to the original one. The on track test results showed improvement in the lateral vibration for both running directions. The vibration reduction method of this study can be used for EMU-250 and EMU-320 in future commercial operations.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1535-1545
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• 2005

The study aimed firstly, to develop the women's bodysuit sleeve block construction method adopting the appropriate pattern reduction rates according to the fabric stretch property. Secondly, the details applied to the bodysuit sleeve block drafting (Dr the educational and industrial usage were proposed. For these, several distinguishing bodysuit sleeve pattern making methods(i.e. Joseph-Armstrong: T1, Shoben & Ward: T2, Esmod: T3 and Mixed Joseph-Armstrong: T4) were analyzed and divided into two categories that adopt 1) the equally (i.e., T1) and 2) the differently(i.e., T2, T3 & T4) distributed front and back armhole length measurements. Women's sleeve samples were made for the research using the same stretch fabric($50\%\;and\; 70\%$ in wale and course each) to the previous research. A group comprising 5 relevant experts evaluated the fit and comfort features of the samples. Experiments analyzed the appearance of sleeve samples focused on total 13 evaluation parts(including the front/side/back fit tolerance, sleeve centre line, sleeve length, appropriateness of the sleeve appearance balanced with the bodysuit and etc.): and performed the comfort test evaluating three kinds(vertical-front/vertical-side/ horizontal) of arm movements. The most appropriate bodysuit sleeve to fulfil the original aims of the study was suggested. The findings and suggestions throughout the study were: 1) the measurements and required reduction rates for the bodysuit sleeve block developed: outer sleeve length (with 1.0 RR), crown height(with 0.7 RR), front and back armhole lengths measured on the bodysuit blocks ($0\%$ ease amount), elbow width(0.9/0.95 RR), wrist girth measurements(from $12\%\;to\;18\%$ tolerances can be given to): and 2) the differently distributed front and back armhole length measurements resulted in the better fit and comfort through the research.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.936-942
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• 2018

The diagnostic multi-leaf collimator preventing unnecessary dose from entering into patients during the diagnostic examination was made in this study. The movement of the entire 50 leaves was embodied with the group of 25 ones thereof configured in a pair facing each other on the left and right of the median line. Dimensions of the length, width, and height of each shielding leaf were $5{\times}0.5{\times}0.5cm^3$ resulting in the maximum boost field of $10{\times}10cm^2$. The material of multi-leaf collimator had the excellence on the machinability with the use of the SKD-11 alloy tool steel having the high wear resistance against frequent movement, and it was devised to control both-side's shielding leaves by moving 2 motors unlike existing remedial multi-leaf collimator that use as many motors as the number of 50 shielding leaves. Thereafter, the transmission dose of leaves, cross-leaf leakage dose, and inter-leaf leakage dose were measured by the developed multi-leaf collimator attached to X-ray equipment. An ionization chamber was used to detect doses there from, and the comparative analysis was carried out by means of the radiographic film that was easy to detect the dose leakage in between each leaf. Results obtained from the test conducted in comparative analysis yielded approximately 98%, 96%, and 94% of shielding efficiency realized at each level of energy of 80kV, 100kV, and 120kV it was confirmed there was no dose leakage resulted from the varied level of irradiation energy. Thus the multi-leaf collimator to be developed based on this study is thought that it could fully reduce the unnecessary dose to patients in the diagnostic test and the shielding efficiency thereof is expected to be increasing if it is made in a miniaturized form with a way of increasing the thickness of each leaf later for an extended application to general diagnostic purposes.

• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.114-119
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• 2000

The soft tissue defects including the Achilles tendon are complex and very difficult to reconstruct. Recently, several free composite flaps including the tendon have been used to reconstruct large defects in this area in an one-stage effort. Our case presents a patient reconstructed with free composite dorsalis pedis flap along with the extensor digitorum longus and superficial peroneal nerve for extensive defects of the Achilles tendon and surrounding soft tissue. A 36-year-old-man sustained an open injury to the Achilles tendon. He was referred to our department with gross infection of the wound and complete rupture of the tendon associated with loss of skin following reduction of distal tibial bone fracture. After extensive debridement, $6{\times}8cm$ of skin loss and 8cm of tendon defect was noted. Corresponding to the size of the defect, the composite dorsalis pedis flap was raised as a neurosensory unit including the extensor digitorum longus to provide tendon repair and sensate skin for an one-stage reconstruction. One tendon slip was sutured to the soleus musculotendinous portion, the other two were sutured to the gastrocnemius musculotendinous portion with 2-0 Prolene. The superficial peroneal nerve was then coaptated to the medial sural cutaneous nerve. The anterior tibial artery and vein were anastomosed to the posterior tibial artery and accompanying vein in an end to end fashion. After 12 months of follow-up, 5 degrees of dorsiflexion due to the checkrein deformity and 58 degrees of plantar flexion was achieved. The patient was able to walk without crutches. Twopoint discrimination and moving two-point discrimination were more than 1mm at the transferred flap site. The donor site healed uneventfully. Of the various free composite flaps for the Achilles tendon reconstruction when skin coverage is also needed, we recommand the composite dorsalis pedis flap. The advantages such as to control infection, adequate restoration of ankle contour for normal foot wear, transfer of the long tendinous portion, and protective sensation makes this flap our first choice for reconstruction of soft tissue defect including the Achilles tendon.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.