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Evaluation of Shear Bond Strength and Adhesive Bond Durability of Mixed Species Structural Glued Laminated Timber (이수종 구조용집성재의 전단접착력 및 접착내구성 평가)

  • Shim, Sangro;Yeo, Hwanmyeong;Shim, Kugbo
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.1 s.129
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    • pp.87-96
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    • 2005
  • This study was carried out to evaluate the shear bond strength and adhesive bond durability of structural glued laminated timber (glulam) manufactured with mixed species lumber of Korean red pine, Korean pine and Japanese larch, using resorcinol adhesive and water-based polymeric-isocyanate adhesive (WPI). Each board used as a glulam lamina was graded by visual inspection. The visual lumber grade of the all species was very low due to the large size and number of knots and the steep slope of grain. In view of the results, appropriate pruning, sawing and drying processes might be needed to produce high grade lamina lumber with small knot size and drying defect free. Shear bond strength of every tested glulam specimen ranged between 7.9 and $9.9N/mm^2$, and much higher than the Korean Standard (KS) for glulam shear bond strength, $7.1N/mm^2$. There was not much shear bond strength difference between wood/resorcinol and wood/WPI. The resorcinol adhesive bond durability exceeded KS requirements. However, delamination on the end-grain surfaces of WPI glulam submerged in both room temperature and boiling water severely occurred, and its durability did not meet KS requirements. Further investigations may be required, and special care should be taken, to ensure long service life of WPI glulam used for exterior application. Results of this study are expected to be useful for improvement of mechanical properties and structural performance of mixed species glulam.

Analysis and Evaluation of Glycemic Indices and Glycemic Loads of Frequently Consumed Carbohydrate-Rich Snacks according to Variety and Cooking Method (탄수화물 간식류 식품 및 조리방법에 따른 혈당지수 및 혈당부하지수)

  • Kim, Do Yeon;Lee, Hansongyi;Choi, Eun Young;Lim, Hyunjung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.1
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    • pp.14-23
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    • 2015
  • This study examined the glycemic indices (GIs) and glycemic loads of carbohydrate-rich snacks in Korea according to variety and cooking method. The most popular carbohydrate snacks (corn, potatoes, sweet potatoes, chestnuts, and red beans) from the Korean National Health and Nutrition Examination Survey nutrient database were cooked using a variety of conventional cooking methods (steaming, baking, porridge, puffing, and frying). The GIs of foods were measured in 60 healthy males after receiving permission from the University Hospital institutional review board (KMC IRB 1306-01). Blood glucose and insulin levels were then measured at 0, 15, 30, 60, 90, and 120 min after consuming glucose, and each test food contained 50 g of carbohydrates (corn: 170.0 g, potatoes: 359.7 g, sweet potatoes: 160.3 g, chestnuts: 134.8 g, red beans: 73.1 g). GI values for test foods were calculated based on the increase in the area under the blood glucose response curve for each subject. Steamed potatoes ($93.6{\pm}11.6$), corn porridge ($91.8{\pm}19.5$), baked sweet potatoes ($90.9{\pm}9.6$), baked potatoes ($78.2{\pm}14.5$), steamed corn ($73.4{\pm}9.9$), and steamed sweet potatoes ($70.8{\pm}6.1$) were shown to be considered high GI foods, whereas baked chestnuts ($54.3{\pm}6.3$), red bean porridge ($33.1{\pm}5.5$), steamed red beans ($22.1{\pm}3.2$), fried potatoes ($41.5{\pm}7.8$), and ground and pan-fried potatoes ($28.0{\pm}5.1$) were considered as low GI foods. The results suggest that the cooking method of carbohydrate-rich snacks is an important determinant of GI values.

Effect of Green Tea and Saw Dust Contents on Dynamic Modulus of Elasticity of Hybrid Composite Boards and Prediction of Static Bending Strength Performances (이종복합보드의 동적탄성률에 미치는 녹차와 톱밥 배합비율의 영향 및 정적 휨 강도성능의 예측)

  • Park, Han-Min;Lee, Soo-Kyeong;Seok, Ji-Hoon;Choi, Nam-Kyeong;Kwon, Chang-Bae;Heo, Hwang-Sun;Byeon, Hee-Seop;Yang, Jae-Kyung;Kim, Jong-Chul
    • Journal of agriculture & life science
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    • v.46 no.2
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    • pp.9-17
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    • 2012
  • In this study, in addition to the green tea - wood fiber hybrid composite boards of previous researches, to make effective use of saw dust of domestic cypress tree with functionalities and application as interior materials, eco-friendly hybrid composite boards were manufactured from wood fiber, green tea and saw dust of cypress tree. We investigated the effect of the component ratio of saw dust and green tea on dynamic MOE (modulus of elasticity). Dynamic MOE was within 1.41~1.65 GPa, and showed the highest value in wood fiber : green tea : saw dust = 50 : 40 : 10 of the component ratio, and had the lowest value in 50 : 30 : 20 of component ratio. These values were 1.4~1.6 times higher than static bending MOE of wood fiber - saw dust - green tea hybrid composite boards, and were 2.0~2.9 times lower than those of green tea - wood fiber hybrid composite boards reported in the previous researches. From the results of correlation regression analyses between dynamic MOE and static strength performances, a very high correlation coefficients were obtained, therefore it was found that static bending strength performances can be estimated with a high reliability from dynamic MOE.

Effect of Green Tea and Saw Dust Contents on Static Bending Strength Performance of Hybrid Boards Composed of Wood Fiber, Saw Dust and Green Tea (목재섬유, 톱밥 및 녹차 이종복합보드의 정적 휨 강도성능에 미치는 녹차 및 톱밥 배합비율의 영향)

  • Park, Han-Min;Lee, Soo-Kyeong;Seok, Ji-Hoon;Choi, Nam-Kyung;Kwon, Chang-Bae;Heo, Hwang-Sun;Kim, Jong-Chul
    • Journal of agriculture & life science
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    • v.45 no.6
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    • pp.41-46
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    • 2011
  • In this study, in addition to the green tea-wood fiber hybrid composite boards of previous researches, to make effective use of saw dust of domestic cypress tree with functionalities and application as interior materials, eco-friendly hybrid composite boards were manufactured from wood fiber, green tea and saw dust of cypress tree. We investigated the effect of the component ratio of saw dust and green tea on static bending strength performances. Static bending MOE (modulus of elasticity) was within 0.956~1.18GPa, and showed the highest value in wood fiber : green tea : saw dust = 50 : 40 : 10 of the component ratio, and had the lowest value in 50 : 30 : 20 of component ratio. These values were 2.0~3.1times lower than those of green tea-wood fiber hybrid composite boards reported in the previous researches. The bending MOR (modulus of rupture) showed 8.99~11.5MPa, the change of the bending MOR with component ratio of the factors was the same as that of bending MOE. These values had 1.9~3.5 times lower value than those of green tea-wood fiber hybrid composite boards, and showed the slightly lower values than the MOR of particle boards (PB) and medium density fiberboards (MDF) prescribed in Korean Industrial Standard. Therefore, it is considered that these hybrid composite boards need to improve strength performances by component ratio change, hybrid composite with other materials and adhesive change etc. in order to industrialize the hybrid composite boards.

Prelaunch Study of Validation for the Geostationary Ocean Color Imager (GOCI) (정지궤도 해색탑재체(GOCI) 자료 검정을 위한 사전연구)

  • Ryu, Joo-Hyung;Moon, Jeong-Eon;Son, Young-Baek;Cho, Seong-Ick;Min, Jee-Eun;Yang, Chan-Su;Ahn, Yu-Hwan;Shim, Jae-Seol
    • Korean Journal of Remote Sensing
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    • v.26 no.2
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    • pp.251-262
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    • 2010
  • In order to provide quantitative control of the standard products of Geostationary Ocean Color Imager (GOCI), on-board radiometric correction, atmospheric correction, and bio-optical algorithm are obtained continuously by comprehensive and consistent calibration and validation procedures. The calibration/validation for radiometric, atmospheric, and bio-optical data of GOCI uses temperature, salinity, ocean optics, fluorescence, and turbidity data sets from buoy and platform systems, and periodic oceanic environmental data. For calibration and validation of GOCI, we compared radiometric data between in-situ measurement and HyperSAS data installed in the Ieodo ocean research station, and between HyperSAS and SeaWiFS radiance. HyperSAS data were slightly different in in-situ radiance and irradiance, but they did not have spectral shift in absorption bands. Although all radiance bands measured between HyperSAS and SeaWiFS had an average 25% error, the 11% absolute error was relatively lower when atmospheric correction bands were omitted. This error is related to the SeaWiFS standard atmospheric correction process. We have to consider and improve this error rate for calibration and validation of GOCI. A reference target site around Dokdo Island was used for studying calibration and validation of GOCI. In-situ ocean- and bio-optical data were collected during August and October, 2009. Reflectance spectra around Dokdo Island showed optical characteristic of Case-1 Water. Absorption spectra of chlorophyll, suspended matter, and dissolved organic matter also showed their spectral characteristics. MODIS Aqua-derived chlorophyll-a concentration was well correlated with in-situ fluorometer value, which installed in Dokdo buoy. As we strive to solv the problems of radiometric, atmospheric, and bio-optical correction, it is important to be able to progress and improve the future quality of calibration and validation of GOCI.

Characteristics of the Electro-Optical Camera(EOC) (다목적실용위성탑재 전자광학카메라(EOC)의 성능 특성)

  • Seunghoon Lee;Hyung-Sik Shim;Hong-Yul Paik
    • Korean Journal of Remote Sensing
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    • v.14 no.3
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    • pp.213-222
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    • 1998
  • Electro-Optical Camera(EOC) is the main payload of the KOrea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including a Digital Terrain Elevation Map(DTEM). This instalment which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510~730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response, the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the users of EOC data. The modulation transfer function of EOC was measured as greater than 16 % at Nyquist frequency over the entire field of view, which exceeds its requirement of larger than 10 %. The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.

The Effect of Exercise Program for Prevention of Falling on Physical Fitness, Posture and Fall Prevention Self-Efficacy for Elderly Women (넘어짐 예방 운동이 여성노인의 체력, 자세, 낙상효능감에 미치는 영향)

  • Son, Nam Jeong;Yi, Kyung Ock;An, Ju Yeun
    • 한국노년학
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    • v.37 no.1
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    • pp.237-250
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    • 2017
  • The purpose of this study is to analyze the effects of exercise program for prevention of falling on physical fitness, posture and fall prevention self-efficacy for elderly women. 30 females above the age of 65 were subjects for this study. Over an twelve week period, 14women in the experimental group performed exercise 2 times a week for 60 minutes per session. 16women in the control group didn't participate in the exercise program. The independent variable was a exercise program for prevention of falling. Dependent variables were physical fitness, posture and fall prevention self-efficacy. Prevention of falling exercise program is consisted of an elastic band using exercise and Korean dance movement exercise. Physical fitness consisted of grip strength, upper and lower body endurance, cardiovascular endurance, flexibility, balance, coordination. The posture was measured the static posture when standing, using a high-resolution camera, body style to automatically measure the distance and angle(M-zen, Korea). Posture was measured in both the coronal and sagittal plane via reference board. Fall prevention self-efficacy was measured via questionnaire using the Korea Falls Self-Efficacy Scale (FES-K). The physical fitness, posture and fall prevention self-efficacy were measured twice with pre and post exercise, and the difference between groups with Wilcox signed rank test, and the group-specific post verification was carried out with U-validated methods (Mann Whitney U test). Statistical significance level was verified by setting the p<.05. Lower body endurance, cardiovascular endurance, flexibility, balance and coordination significantly increased in the experimental group. The control group was no significant increase in physical fitness variables. shoulder slope angle, pelvic slope angle(coronal/sagittal), leg length difference, scapular inferior angle and left/right calcaneus angle significantly decreased in the experimental group. Both the experimental group and control group were no significant increase in fall prevention self efficacy. The prevention of falling exercise program for elderly women indicated the positive changes in physical fitness(except grip strength) and posture(except upper body slope). However, there are no significant differences of falling prevention self-efficacy between the both group. Thus, the prevention of falling exercise program for the elderly has been proved that it is highly efficient on improving physical fitness and posture proofreading. However, we still need to consider supplement exercise for grip strength and upper body slope.

An Analysis on the Knowledge Levels, Attitudes, and Factors Affecting the Choices of Those Who Completed the Education of Persons Conducting Clinical Trial Workers (의약품 임상시험 종사자 교육 이수자의 지식 수준, 태도, 교육 선택 요인 분석)

  • Lee, Yoon Jin;Jang, Hye Yun;Lee, Yu-Mi
    • The Journal of KAIRB
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    • v.3 no.2
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    • pp.19-27
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    • 2021
  • Purpose: This study aimed to analyze the knowledge levels, attitudes, and factors affecting the choices on the education of the participants who completed their education of persons conducting clinical trial workers, and to assess the problems of the current education system for clinical trial workers, leading to improvements. Methods: Clinical trial workers (including principal investigators/subinvestigators, members of the Institutional Review Board [IRB], clinical research coordinators) who were affiliated to one of the 4 university hospitals running their own clinical trial center and IRB in Daegu and completed their education of persons conducting clinical trial workers were the subjects of this study. One hundred seven online questionnaires were answered from 2021-04-02 to 2021-04-17. Descriptive statistics and Pearson correlation analysis were used to analyze the acquired data. Independent t-test and 1-way analysis of variance were used to analyze the differences in the knowledge levels and attitudes following the characteristics of the education participants. Results: The baseline characteristics of the 107 participants were as follows: the majority of the participants were female (72.0%), were in their 30s (36.4%), had a nursing major (29.0%), were clinical research coordinators (63.6%), had never experienced a principal investigator (79.4%), had participated 3 or more educations (58.9%), had completed their maintenance course (55.1%), had 5 or more years of clinical trial experiences (34.6%). The fields on which participants had low levels of objective knowledge were "types and preparations on audits of clinical trials," "regulations on clinical trials (Pharmaceutical Affairs Act, Korea Good Clinical Practice)." The difficulties that the participants faced were on "annual educations" and "lack of information regarding the educations." Factors that showed significant differences in objective knowledge were sex (p=0.02), number of educations (p=0.004), the curriculum of 2020 (p=0.001). Age (p=0.004), having experienced a principal investigator (p=0.006), number of educations (p<0.001), the curriculum of 2020 (p<0.001), clinical trial career (p=0.001) were factors that significantly affected subjective knowledge. Attitudes toward the education were positively correlated with objective knowledge (r=0.20, p=0.04) and subjective knowledge (r=0.32, p=0.001). Major sources through which information on educations was acquired were "institutional notices," and major factors affecting the choices on the education were "when the education took place" and "where the education took place." "Within the affiliated institution," "Online classes (recorded)" and "IRB and review processes" were each the most preferred place, mode, and content of the education. Conclusion: Knowledge levels varied largely among participants who completed their education of persons conducting clinical trial workers, depending on their characteristics such as the number of educations. Participants also complained about their lack of information on educations. The quality of education may be improved if clinical trial organizations are designated as education facilities. Education programs must be developed considering the knowledge level and demand of the participants. Furthermore, as offline classes may be impossible due to pandemics such as the coronavirus disease 2019, the development of diverse and sophisticated online classes is looked forward to.

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Kim Taek-yeong's Return to Korea in 1909 and Scholar Byeoksu in a Pavilion by An Jung-sik (김택영(金澤榮)의 1909년 귀국(歸國)과 안중식(安中植) 필(筆) <벽수거사정도(碧樹居士亭圖)>)

  • Kang, MinKyeong
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.99
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    • pp.30-49
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    • 2021
  • Scholar Byeoksu in a Pavilion by An Jung-sik (1861-1919; sobriquet: Simjeon) was first shown to the public in the exhibition Art of the Korean Empire: The Emergence of Modern Art at the National Museum of Modern and Contemporary Art, Deoksugung. This painting bears poems and inscriptions composed by Kim Taek-yeong (1850-1927; sobriquet: Changgang) and written by Kwon Dong-su (1842-?; sobriquet: Seokun). A rare example of an actual-view landscape painting by An Jung-sik, this painting is significant in that it depicts upper-class houses in Seoul in the early twentieth century. More importantly, it demonstrates an association among intellectuals of the time. Yun Deok-yeong (1873-1940; sobriquet: Byeoksu), who asked An Jung-sik to create this painting, was an uncle of Empress Sunjeonghyo (1894-1966), the consort of Emperor Sunjong. He was one of the most prominent collaborators who promoted the Japanese colonization of Korea. When Emperor Sunjong bestowed Yun Deok-yeong with a hanging board with an inscription reading "Scholar Byeoksu in a Pavilion," Yun requested the production of this painting to mark the event. Kim Taek-yeong, a master of Chinese literature during the late Korean Empire period, sought asylum in Nantong, Jiangsu Province in China with his family a month before the Protectorate Treaty was signed between Korea and Japan in 1905. In 1909, he returned to Korea. His decision to return was greatly influenced by Yun Deok-yeong and Yi Jae-wan (1855-1922). Upon his return, Kim Taek-yeong intended to gather materials for publishing a history book. Also, Kim continuously met his old acquaintances, made new friends, and socialized with them. He built relationships with people from various backgrounds, including those living in regions like Gurye, and even in other countries like Japan. This indicates that intellectuals of the time were still forming networks through poems and prose regardless of their political inclination, social rank, or nationality. Scholar Byeoksu in a Pavilion is of great value in that it shows an aspect of the intellectual exchanges among the learned people of the late nineteenth and early twentieth centuries.

The Study on the Embedded Active Device for Ka-Band using the Component Embedding Process (부품 내장 공정을 이용한 5G용 내장형 능동소자에 관한 연구)

  • Jung, Jae-Woong;Park, Se-Hoon;Ryu, Jong-In
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.3
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    • pp.1-7
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    • 2021
  • In this paper, by embedding a bare-die chip-type drive amplifier into the PCB composed of ABF and FR-4, it implements an embedded active device that can be applied in 28 GHz band modules. The ABF has a dielectric constant of 3.2 and a dielectric loss of 0.016. The FR-4 where the drive amplifier is embedded has a dielectric constant of 3.5 and a dielectric loss of 0.02. The proposed embedded module is processed into two structures, and S-parameter properties are confirmed with measurements. The two process structures are an embedding structure of face-up and an embedding structure of face-down. The fabricated module is measured on a designed test board using Taconic's TLY-5A(dielectric constant : 2.17, dielectric loss : 0.0002). The PCB which embedded into the face-down expected better gain performance due to shorter interconnection-line from the RF pad of the Bear-die chip to the pattern of formed layer. But it is verified that the ground at the bottom of the bear-die chip is grounded Through via, resulting in an oscillation. On the other hand, the face-up structure has a stable gain characteristic of more than 10 dB from 25 GHz to 30 GHz, with a gain of 12.32 dB at the center frequency of 28 GHz. The output characteristics of module embedded into the face-up structure are measured using signal generator and spectrum analyzer. When the input power (Pin) of the signal generator was applied from -10 dBm to 20 dBm, the gain compression point (P1dB) of the embedded module was 20.38 dB. Ultimately, the bare-die chip used in this paper was verified through measurement that the oscillation is improved according to the grounding methods when embedding in a PCB. Thus, the module embedded into the face-up structure will be able to be properly used for communication modules in millimeter wave bands.