• Title/Summary/Keyword: R-404A

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Reliability Assessment Methods for Electronic Component Removed Environmental Materials - focused on Printed Wiring Board without Pb and Br - (환경물질을 제외한 전자부품의 신뢰성평가 방법 연구 -Pb와 Br을 제거한 PWB를 중심으로-)

  • Lee Jong-Beom;Cho Jai-Rip
    • Proceedings of the Korean Reliability Society Conference
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    • 2005.06a
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    • pp.393-404
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    • 2005
  • The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

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The Status and Network Characteristics of Regional Innovation Support Agencies(company support agencies and R&D institutes) in Daegu City, Korea (대구지역 기업지원 및 연구기관 현황과 네트워크의 특성)

  • Lee, Chul-Woo;Kim, Myeong-Yeob
    • Journal of the Korean association of regional geographers
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    • v.11 no.5
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    • pp.391-404
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    • 2005
  • This paper attempts to show the status and network characteristic of regional innovation support agencies(company support agencies and R&D institutes, RISA) which play an important role in the regional system of innovation in Daegu City, using questionnaire data. Most of these agencies were established in 1990s and tend to locate in Buk-Gu and Dalsu-Gu, being major local universities which retain a large number of R&D and industry support agencies. The business areas of the agencies are largely associated with business training and applied research. Their major role is to provide the information that local firms need to acquire. It shows that they have relationships with 1 to 5 agencies, primarily in the form of informal network, for the purpose of sharing information and knowledge about science/technology and market trend. There are not many spin-offs from RISA. But most of spin-offs from RISA are located in Daegu City and maintain cooperative relationships with their parent organization primarily in the form of formal network. The main purpose of cooperative relationships with RISA is to interchange knowledges about technology.

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Characteristic Properties of Enzymatically Hydrolyzed Soy Proteins for the Use in Protein Supplements (단백소재 첨가물로서의 효소분해 대두 단백질의 특성)

  • In, Man-Jin;Kim, Min-Hong;Chae, Hee-Jeong
    • Applied Biological Chemistry
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    • v.40 no.5
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    • pp.404-408
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    • 1997
  • Enzymatically hydrolyzed vegetable protein (eHVP) was produced from soy protein using proteases, and the physicochemical properties were examined. Soy protein hydrolysate of 6% protein and 50% degree of hydrolysis was useful for the base of savory ingredients. The Maillard-reacted and flavoring compound-added hydrolysate had improved flavor. It was for enzymatically hydrolyzed soy sauces and dehydrated seasonings. ISP hydrolysate of low molecular weight $(MW{\sim}250)$ and high protein content (85%) was suitable for special uses such as infant diets, sports nutrition, and medical diets. The eHVP gave no limitation of dosage in the formulation as a flavor enhancer. The byproduct of protein hydrolysis was found to have high content of fiber (21%) and to have potential for the use as dietary fiber or bulking agents.

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$H_2$, $H_{\infty}$, and mixed $H_2/H_{\infty}$ FIR Filters for Discrete-time State Space Models

  • Lee, Young-Sam;Jung, Soo-Yul;Seo, Joong-Eon;Han, Soo-Hee;Kwon, Wook-Hyun
    • Proceedings of the IEEK Conference
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    • 2003.11a
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    • pp.401-404
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    • 2003
  • In this paper, $H_2$, $H_{\infty}$, and mixed $H_2/H_{\infty}$ FIR filters are newly proposed for discrete-time state space signal models. The proposed filters require linearity, unbiased property, FIR structure, and independence of the initial state information in addition to the performance criteria in both $H_2$ and $H_{\infty}$ sense. It is shown that $H_2$, $H_{\infty}$, and mixed $H_2/H_{\infty}$ FIR filter design problems can be converted into convex programming problems via linear matrix inequalities (LMIs) with a linear equality constraint. Simulation studies illustrat that the proposed FIR filter is more robust against uncertainties and has faster convergence than the conventional IIR filters. the conventional IIR filters.

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Process Development of Rotor Shaft using a Large Friction Welding (대형마찰용접을 이용한 로타샤프트 제조공정개발)

  • Jeong, H.S.;Cho, J.R.;Lee, N.K.;Park, H.C.;Choi, S.K.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.401-404
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    • 2007
  • Inertia welding is a solid-state welding process in which butt welds in materials are made in bar and in ring form at the joint face, and energy required for welding is obtained from a rotating flywheel. The stored energy is converted to frictional heat at the interface under axial load. The quality of the welded joint depends on many parameters, including axial force, initial revolution speed and energy, amount of upset, working time, and residual stresses in the joint. Inertia welding was conducted to make the large rotor shaft for low speed marine diesel engine, alloy steel for shaft of 140mm. Due to different material characteristics, such as, thermal conductivity and flow stress, on the two sides of the weld interface, modeling is crucial in determining the optimal weld geometry and parameters. FE simulation was performed by the commercial code DEFORM-2D. A good agreement between the predicted and actual welded shape is observed. It is expected that modeling will significantly reduce the number of experimental trials needed to determine the weld parameters.

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A Novel Maltopentaose-Producing Amylase as a Bread Antistaling Agent

  • Auh, Joong-Hyuck;Lee, Su-Yong;Yoo, Seung-Seok;Son, Hyun-Ju;Lee, Jae-Woo;Lee, Sung-Joon;Kim, Young-Bae;Park, Kwan-Hwa
    • Food Science and Biotechnology
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    • v.14 no.5
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    • pp.681-684
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    • 2005
  • A maltopentaose-producing amylase (G5-amylase) from Bacillus megaterium KSM B-404 was applied to retard bread retrogradation. Retrogradation rates were determined by differential scanning calorimetry. Gel permeation chromatography determined changes in maltooligosaccharide composition and the molecular weight profiles of carbohydrate tractions. The baking process produced maltopentaose and maltotriose by the hydrolysis of starch molecules into small units. Amylose and amylopectin degradation as well as maltooligosaccharides produced by the enzyme were likely responsible for retarding starch retrogradation. Overall, addition of G5-amylase reduced the starch retrogradation rate, and was as effective as Novamyl(R), a commercial enzyme.

A Study of Body Composition, Dietary Behavior, and Exercise among Students at Women's Colleges (여대생의 식생활 양상 및 운동여부와 체성분 구성의 관계)

  • Eom, Ji-Yon;Jung, Duk-Yoo
    • Journal of Korean Public Health Nursing
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    • v.26 no.1
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    • pp.28-37
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    • 2012
  • Purpose: The aim of this study was to examine BMI, body fat mass, percent body fat, waist-hip ratio, soft lean mass, skeletal muscle mass, and fat free mass, and to determine the association between dietary behavior and exercise and body composition among students at women's colleges, and decide on the relationships among them. Method: This study employed a cross-sectional study design and a convenient sampling method. Ultimately, a total of 404 students participated in the study, which was conducted from September 1 to December 22, 2009. Measurements administered were comprised of dietary behavior and a questionnaire on exercise. The SPSS Win 18.0 statistics program was used for analysis of final data. Results: Major findings are as follows: 9.9% of participants showed a high BMI, and more than 56% and 38% of participants showed a high percent body fat and waist-hip ratio, respectively. Dietary behavior showed a significant negative association with percent body fat (r=-0.110, p=0.027) and waist-hip ratio (r=-0.118, p=0.018). Compared with the non-regular exercise group, the regular exercise group showed a high level of soft, lean mass (t=4.15, p<0.001), skeletal muscle mass (t=3.13, p=0.002), and fat free mass (t=4.00, p<0.001). Conclusion: For maintenance of proper body composition, health promotion programs for management of dietary behavior and regular exercise for students at women's colleges should be developed.

Measurement of Tensile Relaxation of Leather for Shoe Uppers (구두 상부용 가죽의 인장 회복량 측정실험)

  • Lee, Jeongmin;Bae, Mincheol;Kim, Yungwoo;Choi, Seongmyung;Baek, Sungkwan;Lee, Hyoungwook
    • Journal of Institute of Convergence Technology
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    • v.7 no.1
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    • pp.7-10
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    • 2017
  • In general, the shoe stretcher is utilized to stretching the leather of shoe upper in the longitudinal direction. In the capstone design class, we tried to make a shoe leather stretcher for the ball of foot. Since a natural cow leather was recovered in length according to relaxation time after stretched, it was difficult to predict the initial amount of set up of stretching. In this paper, tensile and relaxation experiments were conducted in order to predict the amount of initial stretching for appropriate tensile length. Apparatus of leather stretching was designed and strains of leather were measured according to relaxation times of 12, 18, 24 hours after stretching of 24 hours. It was revealed that the ratio of the final relaxed strain and the initial applied strain was about 0.404 with R-square of 0.990 for a shoe cow leather.

A Culture-Independent Comparison of Microbial Communities of Two Maturating Craft Beers Styles

  • Joao Costa;Isabel N. Sierra-Garcia;Angela Cunha
    • Microbiology and Biotechnology Letters
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    • v.50 no.3
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    • pp.404-413
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    • 2022
  • The process of manufacturing craft beer involves a wide variety of spontaneous microorganisms, acting in different stages of the brewing process, that contribute to the distinctive characteristics of each style. The objective of this work was to compare the structure of microbial communities associated with two different craft beer styles (Doppelbock and Märzen lagers), at a late maturation stage, and to identify discriminative, or style-specific taxa. Bacterial and fungal microbial communities were analyzed by Illumina sequencing of 16S rRNA gene of prokaryotes and the ITS 2 spacer of fungi (eukaryotes). Fungal communities in maturating beer were dominated by the yeast Dekkera, and by lactic acid (Lactobacillus and Pediococcus) and acetic acid (Acetobacter) bacteria. The Doppelbock barrels presented more rich and diverse fungal communities. The Märzen barrels were more variable in terms of structure and composition of fungal and bacterial communities, with occurrence of exclusive taxa of fungi (Aspergillus sp.) and bacteria (L. kimchicus). Minority bacterial taxa, differently represented in the microbiome of each barrel, may underlie the variability between barrels and ultimately, the distinctive traits of each style. The composition of the microbial communities indicates that in addition to differences related to upstream stages of the brewing process, the contact with the wood barrels may contribute to the definition of style-specific microbiological traits.

Length-weight relationships and reproductive biology of commercially important fishes from Ribb Reservoir, Ethiopia

  • Agumassie Tesfahun Asres;Sale Alebachew;Negesse Kebtieneh
    • Fisheries and Aquatic Sciences
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    • v.26 no.5
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    • pp.318-335
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    • 2023
  • It is important to understand the biological aspects of fish for fishing management. This study was conducted from February through October 2021. A total of 1,629 fishes were collected using different fishing gears. The length-weight relationship is a power curve for all fishes and showed a significant (r2 > 0.8). All fishes revealed a negative allometric growth pattern except Labeobarbus intermedius. Oreochromis niloticus (1.714 ± 0.009) was found in better condition than other fish species (analysis of variance [ANOVA], p < 0.05). The length at maturity was 24.0 cm and 25.4 cm total length (TL), 28.9 cm and 28.2 cm fork length, and 53.2 cm and 57.5 cm TL for females and males of O. niloticus, L. intermedius and Clarias gariepinus, respectively. Fecundity was ranged between 100-947 eggs/g with absolute fecundity (AF) of 468-3,832 eggs, 200-1,000 eggs/g with AF of 2,752-136,420 eggs, and 505-900 eggs/g with AF of 2,000-6,404 eggs for O. niloticus, C. gariepinus, and L. intermedius, respectively. Their respective mean fecundity was 1,490 ± 91, 23,330 ± 5,070, and 3,096 ± 273 eggs, respectively. Mean fecundity revealed a significant variation between size classes and species (ANOVA, p < 0.05). The fecundity length and fecundity-body weight relationships except (O. niloticus) of fishes were curvilinear while the gonad weight (GW)-fecundity relationship was linear for all fish species. The fecundity was moderately associated with increasing length than body weight, and GW for all fishes (r2 > 0.6). In conclusion, a tangible management setup is required to sustain the use of fish in the reservoir.