• KSBB Journal
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• 제26권4호
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• pp.333-340
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• 2011

In this study, gemcitabine-loaded methoxy poly(ethylene glycol)-b-poly(L-lactide) (MPEG-PLLA) microparticles with different PEG block lengths were prepared by a W/O/W double emulsion technique. The present study focuses on the investigation of the influence of various preparative parameters such as the ratio of internal water phase and oil phase, polymer concentration, solvent composition of organic phase and salt concentration of external water phase on the morphology and encapsulation efficiency of the microparticles. The microparticles fabricated at high volume ratios of internal water phase to oil phase and at high polymer concentrations showed a relatively high encapsulation efficiency and low porosity. When a dichloromethane/ethyl acetate mixture was used as solvent, both the encapsulation efficiency and drug loading of the microparticles decreased as the level of ethyl acetate increased. The addition of a salt (NaCl) to the external water phase significantly improved the encapsulation efficiency up to 40%, and the microparticles became more spherical with their size and porosity decreased.

• 대한수의학회지
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• 제51권1호
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• pp.69-72
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• 2011

Eosinophilic granuloma is a common hypersensitive inflammatory skin disease in cats, and rare in dogs and horses. The skin biopsies of 5 years old female Cocker spaniel and 2 years old female mixed dog had the clinical signs of skin nodules with alopecia were submitted for diagnosis. Solitary skin nodules and papillary nodules were presented on the left external ear and back of Cocker spaniel and on the external ear of mixed dog, respectively. Histopathologically, epidermis of skin showed mild to severe hyperplasia with multifocal ulceration. Small to large irregular, brightly eosinophilic foci with degenerating eosinophils and homogeneous degenerated collagens were existed in the dermis of both ear and back skin. Typical 'flame figures', a mixture of degenerated collagen and degranulated eosinophils, were observed in both cases. Based on the histopathologic findings and special staining characters, 2 cases were diagnosed as canine eosinophilic granuloma. This is the first report for the eosinophilic granuloma of dogs in Korea.

• 한국분무공학회지
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• 제7권2호
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• pp.7-15
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• 2002

A particle flow visualization, electrostatic charging measurement and separation of triboelectrically charged particles in the external electric field by a fluidized bed tribocharger are conducted for the removal of PVC particles from mixed waste plastics. The laboratory-scale triboelectrostatic separation system consists of the fluidized bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PET particles can be imparted negative and positive surface charges respectively due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. To visualize these charged particles, He-Ne laser is used with cylindrical lenses to generate a sheet beam. In the charging measurement, the particle motion analysis system (PMAS), capable of determining particle velocity and diameter. is used to non-intrusively measure particle behavior in high strength electric field. The average charge-to-mass ratios of PVC and PET particles are $1.4\;and\;1.2{\mu}C/kg$, respectively. The highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials for a single-stage processing. The triboelectrostatic separation system using the fluidized tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.

• 한국의류학회지
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• 제42권3호
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• pp.486-502
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• 2018

Mass-production caused by industrialization has led to environmental pollution; however, a potential solution to this problem is the Up-cycling fashion design belonging to the sustainable design category. This study analyzed the material characteristics of each brand fashion product by selecting 21 domestic Up-cycling fashion brands. The product types manufactured by domestic Up-cycling fashion brands could be divided into fashion clothing, bag, and fashion accessories. The materials used for each item included special material, waste fiber, waste leather, waste paper, and others. In the results of analyzing the material characteristics into the external characteristics and internal characteristics, the external characteristics included the durability with less abrasiveness and deformation as well as a mixture with other different materials, while the internal characteristics included a story arousing consumers' empathy, and scarcity without the same design due to the limitation of material.

• 한국기계가공학회지
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• 제20권9호
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• pp.104-109
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• 2021

Tactile sensors and integrated circuits that detect external stimuli have been developed for use in various industries. Most tactile sensors have been developed using the MEMS(micro electro-mechanical systems) process in which metal electrodes and strain sensors are applied to a silicon substrate. However, tactile sensors made of highly brittle silicon lack flexibility and are prone to damage by external forces. Flexible tactile sensors based on polydimethylsiloxane and using a multi-walled carbon nano-tube mixture as a pressure-sensitive material are currently being developed as an alternative to overcome these limitations. In this study, a manufacturing process of pressure-sensitive materials with low initial electrical resistance is developed and applied to the fabrication of flexible tactile sensors. In addition, flexible tactile sensors are developed with pressure-sensitive materials dispensed on a substrate with flexible mechanical properties. Finally, a study is conducted on the change in electrical resistance of pressure-sensitive materials according to the modulus of elasticity of the substrate.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.273-281
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• 2021

The radiological safety of the spent resin treatment facility with a¹⁴C treatment capacity of 1 ton/day was evaluated in terms of the external and internal exposure of worker according to operation scenario. In terms of external dose, the annual dose for close work for 1 h/day at a distance of more than 1 m (19.8 mSv) satisfied the annual dose limit. For 8 h of close work per day, the annual dose exceeded the dose limit. For remote work of 2000 h/year, the annual dose was 14.4 mSv. Lead shielding was considered to reduce exposure dose, and the highest annual dose during close work for 1 h/day corresponded to 6.75 mSv. For close work of 2000 h/year and lead thickness exceeding 1.5 cm, the highest value of annual dose was derived as 13.2 mSv. In terms of internal exposure, the initial year dose was estimated to be 1.14E+03 mSv when conservatively 100% of the nuclides were assumed to leak. The allowable outflow rate was derived as 7.77E-02% and 2.00E-01% for the average limit of 20 mSv and the maximum limit of 50 mSv, respectively, where the annual replacement of the worker was required for 50 mSv.

• Steel and Composite Structures
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• 제50권1호
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• pp.63-75
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• 2024

In this paper, the modified couple stress theory (MCST) and first order shear deformation theory (FSDT) are employed to investigate the free vibration and bending analyses of a three-layered micro-shell sandwiched by piezoelectric layers subjected to an applied voltage and reinforced graphene nanoplatelets (GPLs) under external and internal pressure. The micro-shell is resting on an elastic foundation modeled as Pasternak model. The mixture's rule and Halpin-Tsai model are utilized to compute the effective mechanical properties. By applying Hamilton's principle, the motion equations and associated boundary conditions are derived. Static/ dynamic results are obtained using Navier's method. The results are validated with the previously published works. The numerical results are presented to study and discuss the influences of various parameters on the natural frequencies and deflection of the micro-shell, such as applied voltage, thickness of the piezoelectric layer to radius, length to radius ratio, volume fraction and various distribution pattern of the GPLs, thickness-to-length scale parameter, and foundation coefficients for the both external and internal pressure. The main novelty of this work is simultaneous effect of graphene nanoplatelets as reinforcement and piezoelectric layers on the bending and vibration characteristics of the sandwich micro shell.

• 한방안이비인후피부과학회지
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• 제11권1호
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• pp.197-218
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• 1998

In this study, I invastigate about oriental medical drug, dosage form and directions in external therapy of contact dermatitis. and after study on relationship oriental medical drug, dosage form and directions with cause, symptom and differentiation of symptom and sign. The results are as follows; 1. Most frequently used oriental medical drug is until qing(淸) dynasty Eriocheir sinensis H. Milne-Edwards(蟹), Salix babylonica L.(柳葉), Natrii sulfas(芒硝), Allium macrostemon Bge.(해), Nelumbo nucifera Gaertn.(荷葉), nowadays in Korea and China Phellodendron amurense Rupr.(黃柏), Gypsum(石膏), Rheum palmatum L.(大黃), Baphicacanthus cusia Bremek(靑黛), Talcum(滑石). 2. In the frequency of dosage form, until qing(淸) dynasty powder 1case, liquor 49cases, liquer and solid mixture 58cases, nowadays Korea and China powder 16cases, liquor 96cases, liquer and solid mixture 59cases. 3. Most frequently used directions of dosage is thinly attaching method(薄貼法), attaching method(敷貼法), furnigating and cleansing method(熏洗法), cleansing method(洗傷法), wet dressing method(濕敷法), spreading powder method(撲粉法), plaster method(途차法), rubbing skin method(摩擦法) 4. In the external therapy of contact dermatitis, oriental medical drug's usage is based on stage of contact dermatitis In acute stage, most frequently used drug is heat and damp remove drug(淸熱燥濕藥), nature of drug(藥性) is bitter taste and cold charactor(苦寒), In chronic stage, most frequently used drug is nourishing the blood drug(養血藥), promoting blood circulation drug(活血藥). 5. The dosage form of drug is based on symptom. In acute stage, when papules and vesicles, or erosion and exudation is the main symptom of skin, liquor or powder is used, when erosion and crust is the main symptom of skin, plaster is used. In chronic stage, plaster is used. 6. In the directions of dosage is based on dosage form of drug and symptom. In acute stage, when papules and vesicles is the main symptom of skin, fumigating and cleansing method, cleansing method, plaster method is used, when erosion, vesicles and exudation the main symptom of skill, cleansing method, wet dressing method, spreading powder method, attaching method, spreading powder method is used, when crust is the main symptom of skin, plaster method is used. In chronic stage, plaster method, rubbing skin method is used.

• 대한방사선기술학회지:방사선기술과학
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• 제41권2호
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• pp.157-162
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• 2018

This study is a search for radiation protection effects of radiation exposure on the organogenic period during the prenatal period, which is known to be the most likely to have congenital malformations by radiation exposure. To study the radiation protection for the mixture of selenium that is strong antioxidant and folic acid that is essential vitamin for DNA synthesis, 2 Gy of radiation was irradiated to pregnant female rats. then, after 14 days of fetal birth, observing blood components, SOD(Superoxide Dismutase), histological changes and external malformations. There was a significant protective effect to reduce blood cell damage(p<0.05) in the irradiation group after selenium and folic acid mixture were administered than irradiation group, and the activation of SOD which is antioxidant enzymes was increased. In addition, confirmed the effect of suppressing the expression of apoptosis of small intestinal cells and the reduction of cerebral cortex layer reduction by radiation. thus, it was confirmed that the congenital malformations were reduced as a result of these protective effects. Based on these results, selenium and folic acid mixture may reduce the incidence of congenital malformations, and it will reduce the damage of the fetus caused by the exposure of the organogenic period due to accidents.

• 복식
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• 제62권4호
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• pp.81-90
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• 2012

The contents of this study are as follows. First, an academic understanding has been achieved by exploring the theoretical concept "allegory", and a new theoretical approached methodology has been sought. Second, an analysis-index of fashion illustration cases has been suggested based on the allegory theory of Craig Owens. Third, in order to draw the characteristics of fashion illustration as viewed from the allegorical viewpoint and find out its feasibility, the case studies has been referred and the internal significance, external significance that combines different characteristics has been extracted. In regards to this study method, literature studies and case studies has been done in parallel with each other. This study was done in the following sequence: the establishment of the study system, the drawing of the allegory-associated concepts and the discovering the characteristics of aesthetic expressions. The results of this study on the expression characteristics of fashion illustration as viewed from the allegorical viewpoint of Craig Owens are as follows. First, the borrowing of image, which is a characteristic of allegory, contains the meaning of uncertainty in the fashion illustration as it expresses the image-synthesis and forms a completely different meaning as the fixed meaning is dissolved and it is utilized as a photo-montage technique. Second, the inference of pictogram is the mixture of linguistic medium and visual medium. Fashion illustration utilizes the characters and transmits the fashion information visually and immanently. It has the characteristic of making the information into pictograms and the internal significances of mutual-text with communication function. Third, the uniqueness of location in the fashion illustration has the special nature of utilized mediums as it is used for advertising or publicizing. The fashion illustration from the viewpoint of allegory has the impermanency of existing only for a limited time and reflects the coincidence that gives the meaning of utilized location according to the season trend. Fourth, the cross-breeding is expressed as the mixture of various materials in the fashion illustration. The expressions made by the mixture of media, such as the use of computer graphic programs mixed together with various materials showed the trend of diversity and genre dissolution.