• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.14-22
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• 2007

In the present study, the effect of milled glass powder and liquid-type nitrile rubber (NBR) on the thermal stability of phenolic resin and the dynamic mechanical properties of glass braid/phenolic composites has been investigated by means of thermogravimetric analysis and dynamical mechanical analysis. It was found that both milled glass power and NBR filled in the waterborne phenolic resin significantly influenced the thermal stability of phenolic resins and the storage modulus and tan delta of the composites. The presence of glass powder increased the thermal stability of the phenolic resin, whereas the presence of NBR resulted in the weight loss in the specific temperature range. The thermal stability of the phenolic resins without and with the fillers was dependent not only on the cure temperature but also on the cure time. The variation of the storage modulus and tan ${\delta}$ of strip-type glass braid/phenolic composites was also influenced with the introduction of glass powder and NBR to the phenolic matrix as well as by the cure conditions given.

• Journal of ILASS-Korea
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• v.25 no.4
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• pp.162-169
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• 2020

The worldwide focus on reducing the emissions, fuel and lubricant consumption in T-GDI engines is leading engineers to consider the crankcase ventilation and oil mist separation system as an important means of control. In today's passenger cars, the oil mist separation systems mainly use the inertia effect (e.g. labyrinth, cyclone etc.). Therefore, this study has investigated high efficiency cylinder head-integrated oil-mist separator by using a compact multi-impactor type oil mist separator system to ensure adequate oil mist separation performance. For this purpose, engine dynamometer testing with oil particle efficiency measurement equipment and 3D two-phase flow simulation have been performed for various engine operating conditions. Tests with an actual engine on a dynamometer showed oil aerosol particle size distributions varied depending on operating conditions. For instance, high rpm and load increases bot only blow-by gases but the amount of small size oil droplets. Submicron-sized particles (less than 0.5 ㎛) were also observed. It is also found that the impactor type separator is able to separate nearly no droplets of diameter lower than 3 ㎛. CFD results showed that the complex aerodynamics processes that lead to strong impingement and break-up can strip out large droplets and generate more small size droplets.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.277-291
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• 2004

The purpose of this study is to analyze the dental hygienists' overall performance in operative restoration and the clinical performance in operative restoration according to dental hygienists' career and to provide basic data for establishing the appropriate range of dental hygienists' work. Subjects of this study are 339 dental hygienists working at dental clinic and hospital nationwide, selected by their working place, career, type of clinic, and location of clinical institution. The distribution of people who responded to the survey shows that 81 belong to beginner level(less than 2 years since entering clinic), 115 intermediate level(2 to 3 years since entering clinic), 81 higher level(4 to 5 years since entering clinic) and 62 advanced level(more than 6 years since their entering clinic). In terms of the types of clinical institution, 178 belong to dental clinics and 161 belong to dental hospitals. The survey used in this study are focused on perception about clinical performance in operative dentistry and adequacy of the work. Operative dentistry consists of operative restoration and endodontic therapy. The operative restoration consists of 15 categories such as patient welcoming, examination and diagnosis, planning of treatment, anesthesia, control of moisture, cavity preparation, pulp protection, matrix band application, amalgam filling, resin filling, glass ionomer cement filling, abrasive strip removal, rubber dam removal, bite check and polishing, patient education, and arrangement. The reliability was Cronbach's Alpha .9453. SPSS 10.0 for Windows was used to analyze the responses. One way ANOVA was utilized to verify the differences in the dental hygienists' job performance in operative restoration and their job performance according to career. When significant difference was found. Duncan multi comparison post hoc was done. To sum up the results of this study, patient welcoming look the first place in the operative restoration. It was followed by patient education, examination and diagnosis, introducing treatment plan, resin filling, glass ionomer cement filling, amalgam filling, bite check and polishing, anesthesia, pulp protection, control of moisture, abrasive strip removal, cavity preparation, matrix band application, rubber dam removal, and anesthesia. In terms of the clinical performance by career, there were significant differences in 19 activities such as medical eraluation, oral examination, patient charting, intra oral readio graphs, firm developing fixing mounting, curing light gun, education of attention content after operation. Based on the results of this study, the specific range of operative restoration for dental hygienists should be focused on providing basic data for dentists' diagnosis, alleviation of fear and aching accompanied by injection and anesthesia, data providing for dentists' decision of anesthesia degree, and maximization of control of moisture.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.37-47
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• 2011

This paper describes the stability evaluation of reinforced earth wall with steel framed-facing based on field test. The reinforced earth wall with steel framed-facing is composed of wall facing, reinforcement and backfill soil. The wall facing is assembled by steel frames and the aggregates are filled in that. The reinforcement is steel strip type based on bearing resistance. Field test is conducted to evaluate for two separate sections and the measurement is conducted according to construction elapsed time of structure for earth pressure, horizontal displacement of wall facing and reinforcement strain. The evaluation results show that the measured earth pressure is less than theoretical earth pressure due to dispersion effect of earth pressure by the applied reinforcement. Also, the horizontal displacement of wall facing satisfied a empirical criteria and the measured strain of reinforcement had nearly no effect on stability of structure. Therefore, the reinforced earth wall with steel framed-facing has a structural stability and it can be commonly used in field.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.94-102
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• 2020

Precast concrete segment arch system has an economic and construct ability that combined with advantage of precast concrete and arch behavior. A precast concrete segment arch system with outrigger is consisted of segmented precast panels, a steel outrigger rib, and V-strip to connect precast panels with a steel outrigger rib and cast-in-place anchors in precast panels to connect V-strip should have sufficient pull-out capacity to form its arch shape by site lifting for assembled precast panels and outriggers. However, it is difficult to secure its embedment depth due to the relatively shallow thickness of precast panel. It can be also occurred that flexure deformation of precast panels caused by its pull-out behaviors. In this study, pull-out capacity of cast-in-place anchor was examined for construction of precast concrete segment arch system with outriggers. Therefore, a total of 24 precast panel specimens were fabricated to examine pull-out capacities of cast-in-place anchor in precast panels, and installation depth of anchors, diameter of anchors and wire mesh effects for the precast panel were examined. From this pull-out tests, its pull-out capacities and failure modes were evaluated and the type of the cast-in-place anchor applicable to the precast concrete segment panel arch system with outriggers was determined from comparison of the design specification values.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.315-321
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• 2006

Inhibitors of acetylcholinesterase(AchE), such as organophosphates and carbamates, interfere the action of AchE in nerve and may lead to a severe impairment of nerve functions or even death. Therefore, insect AchE is the biological target of predominant insecticides used in agriculture. Biosensors are sensitive and can be used as dispoisable sensors for environmental control. In recent years, the use of AchEs in biosensor technology has gained enormous attention, in particular with respect to insecticide detection. The principle of biosensors using AchE as a biological recognition element is based on the inhibition the catalytic activity by the agents to be detected. We here present a strip-type biosensor based on AchE inhibition. In this study, acetylcholinesterase and PVA-SbQ(polyvinyl alcohol functionalized with methyl pyridinium methyl sulfate) were co-immobilized on immobilone-P membranes. Immobilization of the enzymes showed a stability in 6 months without activity loss in $4^{\circ}C$ storage. Enzymes immobilized on surfaces of membrane responded to organophosphates and carbamate more sensitivitive than enzyme in solution. Organophosphates and carbamates concentrations could be detected by entrapped and surface immobilized enzymes, in 5 min. For chlorpyrifos, carbofuran, cabaryl, and methidathion, the detection limits of AChE-strip were similar to that of HPLC/GC method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.62-75
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• 2007

This paper describes a shaped-beam antenna for increasing the antenna gain of a radiating element. The proposed antenna structure is composed of an exciting element and a multi-layered disk array structure(MDAS). The stack micro-strip patch elements were used as the exciter for effectively radiating the electromagnetic power to the MDAS over the broadband, and finite metallic disk array elements - which give the role of a director for shaping the antenna beam with the high gain - were finitely and periodically layered onto it. The efficient power coupling between the exciter and the MDAS should be carried out in such a way that the proposed antenna has a high gain characteristic. The design parameters of the exciter and the MDAS should be optimized together to meet the required specifications to meet the required specifications. In this study, a shaped-beam antenna with high gain was optimally designed under the operating conditions with a linear polarization and the frequency band of $9.6{\sim}10.4\;GHz$. Two methods constructed using thin dielectric film and dielectric foam materials respectively were also proposed in order to implement the MBAS of the antenna. In particular, through the computer simulation process, the electrical performance variations of the antenna with the MDAS realized by the thin dielectric film materials were shown according to the number of disk array elements in the stack layer. Two kinds of antenna breadboard with the MDAS realized with the thin dielectric film and dielectric foam materials were fabricated, but experimentation was conducted only on the antenna breadboard(Type 1) with the MDAS realized with the thin dielectric film materials according to the number of disk array elements in the stack layer in order to compare it with the electrical performance variations obtained during the simulation. The measured antenna gain performance was found to be in good agreement with the simulated one, and showed the periodicity of the antenna gain variations according to the stack layer number of the disk array elements. The electrical performance of the Type 1 antenna was measured at the center frequency of 10 GHz. As the disk away elements became the ten stacks, a maximum antenna gain of 15.65 dBi was obtained, and the measured return loss was not less than 11.4 dB within the operating band. Therefore, a 5 dB gain improvement of the Type 1 antenna can be obtained by the MDAS that is excited by the stack microstrip patch elements. As the disk array elements became the twelve stacks, the antenna gain of the Type 1 was measured to be 1.35 dB more than the antenna gain of the Type 2 by the outer dielectric ring effect, and the 3 dB beam widths measured from the two antenna breadboards were about $28^{\circ}$ and $36^{\circ}$ respectively.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.340-346
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• 1996

In order to find out if staphylococci occur in significant numbers in Korean fermented fish products, a total of 40 different fermented fish products were collected from different markets in Korea and analyzed for their physico-chemical and microbiological states. The pH, salt concentration and water activity of the products were measured and the total viable cell count and the number of Staphylococcus grown on mannitol salt agar were determined. The identification of the strains of Staphylococcus were made by API Staph Strip and MIS identification kits, and the physiological properties of the identified strains were further characterized by different conventional methods. The pH, salt content and water activity of fermented fish samples varied widely from 4.8 to 7.1, 7.4-28.7$%$ and 0.77-0.84, repectively, depending on the type of product. The total viable cell count varied from $10^4-10^9$ cfu/ml, and most of the samples had $10^5-10^6$ cfu/ml No correlation was found between the viable cell count and the pH, NaCl concentration and water activity of the samples. Among the 35 colonies identified as Staphylococcus strains by the identification kits, S. xylosus was the most frequently occurring strain marking 17, and S. warneri was 8, S. epidermidis 4 and S. cohnii 2. S. hominis, S. saprophyticus, S. haemolyticus and S. aureus were also identified once each. In some samples (K-3, P-6, K-8, G-5 and G-10), 2-3 different species of Staphylococcus were found. Considering the region of sampling, among the 10 samples from Kunsan 5 were identified as S. warneri, while in the other regions S. xylosus was predominant. Although the physiological characteristics of the identified strains were generally consistent with those in Bergey's Manual, some discrepances were also observed. All the strains were highly salt tolerant, growing in the media containing over 18$%$ NaCl. All the strains except S. aureus (G-11) showed negative in hemolysis activity, plasma coagulation and DNase tests. All the strains including S. aureus (G-11) showed negative in enterotoxin test.

• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.1 s.26
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• pp.1-11
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• 1988

This study dealt with the Dopo, one of the representative ceremonial dress that acclasical scholar used after the middle of the period of the Chosun dynasty. This study represents the period of Dopo's formation and its origin, and the characteristics of the weary of Dopo in Young Dong Province Area is arranged by folkloric method on the base of the exisitng facilities. Dopo has worn since the middle of the period of the Chosun dynasty. It is the kind of Jig young Po that its back is cuffed for convenience and has another cloth as a ceremonial dress. It is thought to be one of the national customs pos formed by the mixture of the big sleeve type which is influenced by confusion life feeling. It seemed that the name of DoPo comes from the Jigchal, an ordinary dress of a high official in China, which is call Dopo. This Dopo is changed and received and so disappeared but it is still used such as ceremonial dress, the necessary articles for marriage of the bride, a bridegroom's liturgical vestments of a memorial service held on the anniversary of the death of a person, mourning dress and a shroud grave clothes. This area has different characters on wearing customs. It is changed into the kind of Dopo, with its back not cutting. The hemp sack is almost used as its subject matter. It doesn't have collar strip for the classification of one's family in any case, and Dopo which is prepared for necessary articles for marriage can not be taken tack after seperating by divorce.

• KIEAE Journal
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• v.12 no.5
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• pp.3-10
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• 2012

In this study, the influence of decentralized rainwater management over the changes in evapotranspiration was analyzed. The analysis method was obtained by establishing the decentralized rainwater management plan according to different scenarios, and subsequently examined evapotranspiration in the plan. Scenario 1 refers to the analysis of the existing situation, in which was 100% of a parking lot is asphalt pavement. In Scenario 2, the pavement of the parking surface in the parking lot is replaced with lawn blocks. In Scenario 3, some asphalt pavement was removed to establish a flower-bed type infiltration system to allow rainwater to permeate. In Scenario 4, infiltration and storage of rain water would be achieved by transforming the parking surface into lawn blocks, keeping the asphalt for the parking road while establishing a vegetation strip. The amount of evapotranspiration of the target site was analyzed with a water budget analysis program (CAT) using the 2001 meteorological data for each scenario According to the analysis values of S2 and S3, it was found that evapotranspiration is critically affected by the amount of area replaced with pervious area in the total target site. An energy equivalent to 680kWh is required for 1 ton of water to evaporate. Hence, it can be seen that the active inducement of evapotranspiration in urban area makes a positive contribution not only to heat island mitigation, but also to the small-scale water circulation process in a city.