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        검색결과 97

        23.
        2016.10 구독 인증기관·개인회원 무료
        Two different types of acetylcholinesterae (AChE1 and AChE2) are present in majority of insects, including the Western honey bee. Out of the two honey bee AChEs (AmAChEs), the soluble AmAChE1 with little catalytic activity is widely distributed in both neuronal and non-neuronal tissues, including fat body. In this study, to identify stresss factors that can induce AmAChE expression, we tested various conditions that honey bees can encounter in natural setting, including heat shock, cold shock, bacterial challenge (Escherichia coli and Staphylococcus aureus) and Varroa mite infestations, and evaluated their effects on AmAChE expression. Among the stress factors tested, only heat shock condition induced AmAChE expression in a dose dependet manner. This finding suggests that one function of AmAChE1 is related with thermoregulations, especially against heat shock stress in honey bees.
        24.
        2016.05 구독 인증기관·개인회원 무료
        본 연구는 정밀여과막의 막오염 수준을 예측할 수 있는 막오염 평가지표 개발에 관한 것이다. 막오염 지표는 세공크기가 0.1 μm인 Polyvinylidene fluoride (PVDF) 재질의 침지형 중공사 미니모듈을 이용한 실험장치로 측정되었다. 유입 수는 막오염 메커니즘을 대표할 수 있는 막오염 물질인 Kaolin, Silica, Humic Acid, Alginate를 최적의 비율로 조합한 표준 조제수를 이용하였으며, 단시간에 막오염의 변별력을 높이기 위해 한강원수 기준으로 가혹조건의 농도를 적용하였다. 이 막오염 평가지표의 타당성 검증은 미니모듈과 현장 실규모 모듈의 평 가결과를 비교함으로써 수행하였다. 본 막오염 지표는 막오염의 속도를 예측하 기 위한 객관적인 지표로 활용이 가능하다고 판단되며, 미니모듈 측정결과는 정수장내 막면적 50 m2의 실규모 모듈의 결과와 부합되는 것으로 나타났다.
        25.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aging of Korea is rapidly advancing in an unprecedented rate in the world. Indoor and outdoor safety accidents involving the elderly frequently occur, with elderly population increasing. Because the physical strength of elderly is decreased, it is necessary to develop devices that aid the everyday life of the elderly to prevent safety accidents. Among many activities, the motions of standing from and sitting on a chair require much physical strength from particular body parts, which causes an overload for particular body parts. To the elderly the repeating motion of standing from and sitting down on a chair is burdensome, because they do not have enough physical strength compare to young persons . As a result the elderly could be injured or falling during standing or sitting. Therefore, the development of a lift chair that considers the problems mentioned above is necessary to prevent the safety accidents of the elderly. The study designed a non-motorized lift chair that comfortably aids the standing and sitting down motion for the use of the elderly by reflecting the anthropometric data of the Korean elderly over 65 years old. Also the design was implemented to smoothly aid the standing motion by considering the knee angle of the elderly when standing. Because the regained strength to stand from a chair is depend on the knee angle. Unlike existing lift devices, this device utilizes a tilting mechanism that does not use electric power so that the product could be composed inexpensively than existing chairs released in the market.
        4,000원
        26.
        2015.12 구독 인증기관 무료, 개인회원 유료
        The aim of the present study was to investigate sex- and age-associated clinico-metabolic characteristics of urinary stone patients. A retrospective review was performed on data from 2,009 consecutive patients presenting with their first urinary stone episode between 2005 and 2013. Of the 2,009 patients, 1,426 (71.0%) satisfied the inclusion criteria and were enrolled in the study. Patients were grouped by age (<60, ≥60 years old) and sex. The medical history and 24 hr urinary chemistry results of each patient were obtained. The mean age of the 165 (11.6%) patients aged 60 or over was 65.5 ± 4.2 years. Body mass index was greater in elderly females than in younger females (p=0.031). After stratification by sex and age, lower urinary excretion of calcium and uric acid was a protective factor for both sexes among the elderly (p<0.05, each, respectively). Low urine pH was a common risk factor for both sexes among the elderly (p=0.013 in males, p=0.047 in females, respectively), whereas lower citrate excretion was a risk factor for only the elderly female group (p=0.004). With regard to urinary metabolic abnormalities, elderly females showed higher incidence of hypocitraturia compared to younger females (p=0.049). In conclusion, this study demonstrated the sex- and age-associated clinico-metabolic characteristics of urinary stone patients. Thus, it is important to tailor metabolic evaluation and medical prevention therapies for patient according to sex and gender characteristics.
        4,000원
        32.
        2015.09 구독 인증기관 무료, 개인회원 유료
        Micro-electromechanical systems (MEMS) 구조물용 고 종횡비의 외팔보 제작을 목적으로 초임계 이산화탄 소를 사용한 건식 식각 실험을 진행하였다. 건식 식각 실험은 초임계 이산화탄소에 50% 불산 (HF) 원액과 공용매 (물, 메탄올, 에탄올, 이소프로필 알콜)를 사용하여 진행되었다. 희생 실리카 층을 식각하여 드러난 MEMS 외팔보 빔 은 주사전자현미경을 이용하여 관찰하였다. HF원액을 사용한 건식 식각 실험은 종횡비 1 : 150의 외팔보 빔까지 기 판과 접착없이 단독으로 서 있는 형태로 제작되었다. 공용매로 메탄올과 에탄올을 사용한 건식 식각의 결과에서는 종 횡비 1 : 75 까지 접착없이 제작할 수 있었고, 이소프로필 알콜을 공용매로 첨가한 실험 결과에서는 종횡비 1 : 37.5 까지 접착없이 제작할 수 있었다. 본 연구의 결과 건식 식각과정에서 알콜계 공용매의 첨가는 대체로 식각 성능을 저 하시킴을 알 수 있었다.
        4,000원
        33.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, temperature variation characteristics in a flat plate with sheath heater are investigated through experiment and numerical analysis. ANSYS fluent is used to calculate the temperature distribution in the heating plate system. Transient condition is applied to observe temperature variation with the sheath heater operation, and thermal resistance on the contacted surfaces is also considered. Experimental data agree well with numerical results obtained for heat generation rate from sheath heater, Local temperature variation on the surface of flat plate is also predicted through this simulation. There is large temperature variation in the air surrounded flat plate, especially at the top of flat plate with natural convective heat transfer. These results will be helpful in optimal design for various systems equipped with sheath heater.
        4,000원
        34.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Caliber persistent artery (CPA) is a vascular anomaly presenting as a bluish and pulsatile artery in the subepithelial tissue. Although the incidence of CPA was debated, many CPAs occurred in the perioral and facial tissues at which the embryonal strapedial artery networks were distributed. The present study demonstrated a case of CPA occurred in the retromolar buccal mucosa in a 37 years old male. The lesion showed many pinkish granular spots, but was asymptomatic except biting irritation during mastication. It had slowly increased in size up to 20 × 25 mm for 3 years, and recently became hemorrhagic due to the biting injury between left upper and lower second molars. With the fear of oral cancer an incisional biopsy was performed, and followed by histological and immunohistochemical study. Histologically the lesion showed many tortuous artery localized at the submucosa area, and the arterial wall was thick and its lumen was narrowed and shrunken. In the immunochemistry α-SMA was positive for thick smooth muscle layer of artery and arterioles, TGase 2 was weakly positive for the luminal surface of arterial intima, and bFGF was consistently positive for the perivascular fibrous tissue. But PCNA, VEGF, CD31, CMG2, TGF-β1, HSP-70, and 14-3-3 were almost negative for the vascular tissue. Therefore, it was presumed that the lesion was not actively proliferative nor degenerative but still retained its cellular stability and slow growing potential. It was finally diagnosed as CPA differentially from arterio-venous malformation, hemangioma, lymphangioma, and squamous cell carcinoma. The retromolar buccal mucosa CPA is first reported in this study and may present usual clinical findings depending on its size and location. This asymptomatic lesion could be severely hemorrhagic by minor biting injury, therefore, precise differential diagnosis should be made through biopsy, and careful therapy be followed.
        4,000원
        35.
        2015.03 구독 인증기관 무료, 개인회원 유료
        In this study, center marking process is numerically analyzed to investigate the characteristics of deformation of aluminium alloy bracket by the pin load. The proper size of groove which are required for marking system and the pressure of cylinder are predicted through the analyse of stress and strain fields of the plate. The results of this study show that von Mises stress is a maximum when the maximum of reaction force.
        3,000원
        36.
        2015.03 구독 인증기관 무료, 개인회원 유료
        In this study, flow characteristic of small vertical-axis wind turbine was performed to analysis the numerical analysis. Blade geometry in the wind turbine is NACA 6512-43, and various degrees of the wind turbine accelerator were adopted. Numerical models are used for the analysis with CFD program of Ansys fluent and RNG k-e turbulence model was used. Rotational speed value of the wind turbine in analysis condition were obtained by the experiment. When the wind turbine accelerator is equipped, exit velocity of wind turbine accelerator tended to increases. Also RPM of wind turbine is increase. And maximum RPM appeared that wind turbine accelerator in degree 60° is equipped.
        4,000원
        37.
        2015.03 구독 인증기관 무료, 개인회원 유료
        In this study, temperature variation characteristics in the stone board cutting device with sheath heater were analyzed through numerical investigation. Four 2kW sheath heaters whose length and diameter are 1800mm, 11mm are installed, and the initial temperature is -5℃. Also Transient condition is used for temperature variations with the operating time of sheath heater. From the analysis, transient temperature variations of cutting device after operating the sheath heater were predicted. Temperature variations were predicted that mainly appears in part contacted with the sheath heater. The result will be helpful in optimal design for various system equipped with sheath heater.
        3,000원
        38.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The excessive concentration of phosphorus in the river and reservoir is a deteriorating factor for the eutrophication. The converter slag was used to remove the phosphate from the synthetic wastewater. Influencing factors were studied to remove soluble orthophosphate with the different particle sizes through the batch and the column experiments by continuous flow. Freundlich and Langmuir adsorption isotherm constants were obtained from batch experiments with PSA and PSB. Freundlich isotherm was fitted better than Langmuir isotherm. Regression coefficient of Freundlich isotherm was 0.95 for PSA and 0.92 for PSB, respectively. The adsorption kinetics from the batch experiment were revealed that bigger size of convert slag, PSA can be applied for the higher than 3.5 mg/L of phosphate concentration. The pilot plant of continuous flow was applied in order to evaluate the pH variation, breakthrough points and breakthrough adsorption capacity of phosphate. The variation of pH was decreased through the experimental hours. The breakthrough time was 1,432 and 312 hours to 10 mg/L and 50 mg/L for the influent concentration, respectively. The breakthrough adsorption capacity was 3.54 g/kg for 10 mg/L, and 1.72 g/kg for 50 mg/L as influent phosphate concentration.
        4,000원
        40.
        2014.07 구독 인증기관·개인회원 무료
        The online game market has rapidly increased worldwide, especially in China. In 2012, the world game market equaled 111.7 billion. Many game companies compete by launching new online games in various genres. In 2010, Activision Blizzard reported that the World of Warcraft (WOW) is the world’s most popular online game. Chinese gamers constitute more than half of WOW’s 10 million users. Korea is the second largest gaming market. Thus many foreign game companies target Korea and China, in competition with domestic game companies. The purposes are 1) to understand the role of country of origin and /or brand image in game consumer behavior, 2) to find out the difference of game evaluation between game users in China and Korea, and 3) to draw strategic implication game marketers. Consumers expect products from advanced countries to provide superior performance, so they often look to country of origin in evaluating products. Recently, consumers have looked to brand image as another key element in product evaluation. In this research, we study whether gamers evaluate games on the basis of country of origin and/or brand image. In this paper, we add to the gaming research and suggest that the online game market has three dimensions. First, online games are products. Second, online games are service. Last, online games are entertainment. Data collection resulted in 355 usable responses from online game (LOL) users in Korea(166) and China(189). We conduct factor analysis and reliability analysis to check reliability and validity. Country of Origin is the key element for product evaluation of utilitarian goods but it doesn’t have significant effect on product evaluation of hedonic products which mainly provide sensual pleasure, fantasy, and fun to customers such as luxury goods or online game (Dhar & Wertenbroch, 2000).
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