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        검색결과 525

        301.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To prepare alkaline degreasing agents(SADAs), tetrasodium pyrophosphate(TSPP), Na2CO3, Tetronix T-701 (T-701), Na-dioctyl sulfosuccinate(303C), Demol C, and MJU-100A were blended. The prepared degreasing agents were tested with steel specimens and the results were as follows. The degreasing powers of SADA-6(Na2CO3 50g/TSPP 25g/T-701 10g/303C 15g/Demol C 12g/MJU-100A 8g/water 130g mixture) for press-rust preventing oil were 98% and 99% degreasing at 4wt%, 70 ℃ and 90 ℃, respectively; for quenching oil, the degreasing power of SADA-6 was 92% degreasing at 4wt% and 70 ℃. From these results, it was proved that the SADA-6 exhibits a good degreasing power. Foam heights measured immediately after foaming by Ross & Miles method and Ross & Clark method at 6wt% and 60 ℃ were 16mm and 40mm, respectively. SADA-6 was proved a good low foaming degreasing agent.
        4,000원
        302.
        2003.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to assess the effects of ultrasound on adjuvant-induced arthritis in rats. Adjuvant arthritis was induced in 26 female Sprauge-Dawley rats by the subcutaneous injection of a single dose of .1 mL of Complete Freund's Adjuvant (CFA) (1 mg of Mycobacterium Butyricum suspended in .1 paraffin oil) into the right hind paw. After confirming inflammatory edema and arthritis in the paw 2 weeks later, the arthritic rats were divided into 3 groups, i.e., a control group, a pulsed ultrasound group (Group A), and a continuous ultrasound group (Group B) with 8 rats placed in each group. The rats in Group A were treated with pulsed ultrasound at 1 MHz frequency with .5 intensity in 1 : 4 mode for 3 minutes. The rats in Group B were treated with continuous ultrasound at 1 MHz frequency with 2 intensity in the continuous mode for 3 minutes. The ultrasound treatment was done in the left and right ankles for 2 weeks. Clinical, radiographic and histopathologic findings were then evaluated before and after treatment and yielded the following results. 1. No significant difference was present in body weight between the control group and the treated groups. 2. A statistically significant decrease in the edema of the paw was seen in the rats in Group A that was treated with pulsed ultrasound by 26~29 days after the treatment started (p<.05). 3. According to radiological examination, Group A showed the lowest score in arthritis scale which means it showed a tendency to suppress arthritic inflammation of the left and right hind paws. However, no statistically significant difference was present in the score between the control group, Group A and Group B. 4. According to histopathologic findings, the degree of infiltration by inflammatory cells and hypertrophy of the synovium were less in Group A compared with the control group and Group B. The results of the study show that rats that were treated with the pulsed ultrasound effectively suppressed adjuvant arthritis. However, more effort is needed to objectively prove the effectiveness of ultrasound by developing more sensitive testing methods that could quantitatively evaluate the treatment effects of acute rheumatoid arthritis and by trying out different ultrasound treatment methods.
        4,800원
        303.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An intermediate, tetramethylene bis (orthophosphate), was prepared by the esterification of pyrophosphoric acid and l,4-butanediol. Then pyrophosphoric-containing modified polyesters (ATTBs) were synthesized by polycondensation of tetramethylene bis(orthophosphate), trimethylolpropane, adipic acid, and l,4-butanediol. The content of l,4-butanediol was varied from 10 to 20wt% for the reaction. The increase of the amount of l,4-butanediol in the synthesis of ATTBs resulted in increase in average molecular weight and decrease in kinematic viscosity owing to the excellent flowability and reactivity of l,4-butanediol.
        4,000원
        304.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acidic degreasing agent(AADA) was prepared by blending sorbitol, Newpol PE-68, Na-dioctyl sulfosuccinate, Tetronix T-70l, MJU-100A, n-octanoic acid, and phosphoric acid, The physical properties of AADA tested with aluminum specimen showed the following results ; when 3wt% AADA-5 was performed at 70℃, the degreasing rate was 95% which is comparitively good, and the percentage of etching was 0.277% which was found to be less than that of commercialized product. when 20wt% of AADA-5 was added at 65℃, the percentage of derusting was 91% and the good defoaming effect proved by following low foaming power tests respectively : Ross and Miles, and Ross and Clark methods.
        4,000원
        305.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Environmental friendly acrylics/urea high-solid paints (BEHCU) were prepared through the curing reaction of acrylics resin(BEHC) containing 70wt% of solids content and butylated urea curing agent. BEHC was synthesized by addition copolymerization of caprolactone acrylate(CLA), 2-hydroxypropyl methacrylate(2-HPMA), ethyl methacrylate, and n-butyl acrylate. The addition polymerization of these monomers, especially including flexible CLA monomer and 2-HPMA monomer with OH funtional group, under appropriate reaction conditions resulted in polymers with controlled glass transition temperature(Tg) and crosslinking density. The molecular weight(Mw) of these polymers(BEHCs) was 2940~3240 and polydispersity (Mw/Mn) was in the range of 1.61~1.72. The viscosity and the molecular weight of these acrylic resins increased with increasing Tg. The coated films were prepared using curing reaction between BEHC resin and butylated urea curing agent at 100℃ for 30 minutes. Our experimental resulted showed that enhancement of the coating properties such as adhesion, flexibility, impact resistance, water resistance, and abrasion resistance could be expected through introducing CLA component in acrylic resin for the high-solid content acrylics/urea coatings.
        4,300원
        306.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to prepare a softener, alkyl imidazoline salt, fatty carbamide salt, and fatty polyamide salt were synthesized first, and then the synthesized salts were blended. The prepared softeners were applied to acrylic fibers, and then several properties were tested. As a result, the prepared softeners show good softening and lubricating properties, and they also show a little antistatic property. Through bending resistance tests and measurements of feeling change of acrylic fibers treated with the softeners, it was proved that the prepared softeners are durable softeners.
        4,000원
        308.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,800원
        310.
        2002.10 구독 인증기관 무료, 개인회원 유료
        The shape of foot differs with races, age, gender, the type and size of foot, and the height of heel. These differences are considered enough when the shoe is made. In this paper, we will discussed relationship between the age and foot length. In shoe industry, age is generally divided into infant, children, young and adult shoes. As korean"s foot size is considered, we want to check whether these categories are good using several classification techniques.
        4,000원
        311.
        2002.10 구독 인증기관 무료, 개인회원 유료
        Recently, companies are currently focusing on making huge investments in both time and money on CRM by which they can generate profits through establishing long term relationship with customers while understanding customers" propositions by gathering and analyzing information on customers. But, CRM has many problems that make companies confused. Yet, this phenomenon can be regarded as an interim one. In fact, some cases that successfully introduced CRM show that CRM is migrating from small scale which is typical when introduced to larger scale through various tests. Therefore, this study tries to grasp common problems which most companies utilizing CRM are facing and present solutions to such problems in utilizing CRM. For these purposes, we try to determine the most important and most urgent factors in CRM utilization by using AHP, one of the Multi-criteria decision-making methods proposed by Satty. AHP is widely used for determining relative magnitude per evaluation item, i. e. priority on problems and is expected to make more systematic and objective evaluations than conventional methods do. Even in the present situation where any general criterion on CRM dose not exist, utilization of CRM is expected to be actively continued, which will cause many problems. In this regard, evaluating CRM counts. This study also tries to present a model applicable to such CRM evaluations.
        4,000원
        312.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현지투자환경이 불확실한 경우 기업들은 어떠한 과정과 요인에 의해 해외직접투자를 확대하는가? 미얀마와 베트남에 진출한 3개 한국기업의 해외직접투자 확대과정을 분석한 결과 사례기업들은 초기투자를 통해 성장기반을 확보한 다음 현지사업역량을 구축하면서 투자의 불확실성이 줄거나 유리한 투자기회가 왔을 때 후속투자를 실행하는 것으로 나타났다. 또한 불확실한 투자환경 하에서 투자의 철회불가능성에 대처하고 투자가치를 극대화하기 위해 소규모 합작을 바탕으로 해외직접투자를 확대하는 것으로 분석되었다.
        8,100원
        316.
        2001.11 구독 인증기관 무료, 개인회원 유료
        도자기 산업의 국내 수요확산과 국제시장에서의 경쟁력확보를 위한 실태조사 및 문제점을 분석하고, 도자기 산업발전을 위한 개선방안 수립 및 고부가가치 브랜드상품의 개발을 위한 구체적인 방안을 도출하여 관광상품 발전계획과 연계하는「관광상품 발전계획-도자기브랜드화」의 발전전략 개발과 실천프로그램 개발을 목적으로 하며, 또한 미국, 일본, 영국 통의 도자기 산업발전과 브랜드 전략과 도자기제품별 인증기준과 활용실태 등 해외 도자기산업 실태을 사례 조사하여 도자기 상품과 세계적 브랜드 제품과의 갭을 분석 벤치마킹 가능부문 활용방안을 모색하려 한다.
        4,000원
        318.
        2001.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Metal organic chemical vapor deposition (MOCVB)법을 사용하여 sapphire (0001) 기판 위에 GaN 환충층을 성장하고, 그 위에 GaN 에피층을 성장하였다. GaN 완충층은 550˚C에서 약 26 nm에서 130 nm까지 각각 다른 두께로 성장하였고, GaN 에피층은 1100˚C에서 약 4 μm의 두께로 성장하였다. GaN 완충층 성장 후 atomic force microscopy (AFM)으로 표면 형상을 측정하였다. GaN 완충층의 두께가 두꺼워질수록 GaN 에피층의 표면이 매끈해지는 것을 scanning electron microscopy (SEM)으로 관찰하였다. 이것으로 GaN 에피층의 표면은 완충층의 두께와 표면 거칠기와 관계가 있다는 것을 알 수 있었다. GaN 에피층의 결정학적 특성을 double crystal X-ray diffraction (DCXRD)와 Raman spectroscopy로 측정하였다. 성장된 GaN 에퍼층의 광학적 특성을 photoluminescence (PL)로 조사한 결과 두께가 두꺼운 완충층 위에 성장된 에퍼층의 결정성이 더 좋은 반면, 내부 잔류응력은 증가하는 결과를 보였다. 이러한 사실들로부터 완충층의 두께가 두꺼워짐에 따라 내부 자유에너지가 감소하여 에피층 성장시 측면성장을 도와 표면이 매끈해지고, 결정성이 좋아졌다.
        4,000원
        319.
        2001.06 구독 인증기관·개인회원 무료
        열전재료는 열전현상을 가지고 있어 열전발전과 열선냉각이 가능하기 때분에 해저용, 우주용, 군사용의 특수 전원으로 이미 실용화되어있고, 반도체, 레이저 다이오드, 적외선 검출소자 등의 냉각기로 쓰여지고 있어 많은 연구자들이 이들 재료에 대한 연구에 관을 갖고 열전특성을 향상시키기 위하여 많은 연구를 진행하고 있다 이들 열전재료는 사용 온도구역에 따라 3종류로 구분하고 있으며, 실온부근의 저온 영역(20)이하에서는 계 재료, 중온영역(20~50)에서sms
        320.
        2001.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사파이어 (0001) 기판의 활성화 이온빔 (RIB) 처리 후 MOCVD에서 성장한 GaN박막의 열처리를 통한 구조 변화를 살펴보고, 전기적 성질의 변화를 관찰하기 위하여 전기로를 이용하여 열처리를 하였다. 시편의 분석을 위하여 DCXRD, Hall, TEM을 사용하였다. 1000˚C에서 시간을 변화시키면서 열처리한 시편에서 DCXRD의 FWHM는 약 50 arc-sec 정도 감소하였고, Hall 이동도는 약 80cm2/V.sec 정도 향상되었다. 가장 좋은 Hall 이동도를 보인 처리된 시편과 처리 전 시편의 TEM 비교 관찰에서 전위 밀도는 56~69% 정도 감소하였고 격자의 변형도 줄어들었다. 이것은 결정의 질과 전기적 성질 사이의 상관관계를 암시하며, 기판의 RIB 처리와 성장 후 적절한 열처리의 조합이 MOCVD로 성장시킨 GaN 박막의 특성을 개선시키는 것을 명확하게 보여준다.
        4,000원