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        검색결과 1,065

        103.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We studied trichloroethylene (TCE) adsorption from aqueous solutions in equilibrium conditions by activated carbons (AC). They differ in raw materials, porous structure characteristics and chemical state of the surface. TCE adsorption isotherms were found to have a concave shape, which is characteristic of a sorbent—sorbate weak interaction. It can be a result from electrostatic repulsion of organic matter molecule from polar groups on carbon surface and adsorbed water molecules. The basic parameters of adsorption were calculated by the Dubinin–Radushkevich equation. We determined that for AG-OV-1 and SKD-515 in the coordinates of the Dubinin–Radushkevich equation, there are two linear plots suggesting adsorption in pores of different sizes or reorientation of adsorbate molecules on the activated carbon surface. The efficiency of TCE removal by the activated carbons was evaluated. To reduce the TCE to the maximum allowable, the lowest sorbent consumption was observed for AC with the highest values of surface area and micropore volume. However, the high cost and hydrophobicity of these adsorbents make it impractical to use them in adsorption columns with a fixed layer. We offered an adsorbent that reasonably combines extraction efficiency, ease of operation and economic feasibility.
        4,000원
        104.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon short fibers/copper composites with different carbon short fiber contents up to 15 wt.% as reinforcements are prepared to investigate the influence of the carbon short fiber surface coating on the microstructure, density, and electrical properties of the carbon short fibers/copper composites. The carbon short fibers were surface treated by acid functionalization followed by alkaline treatment before the coating process. It was observed from the results that coated type copper nanoparticles were deposited on the surface of the carbon short fibers. The surface treated carbon short fibers were coated by copper using the electroless deposition technique in the alkaline tartrate bath by using formaldehyde as a reducing agent of the copper sulfate. The produced coated carbon short fibers/copper composite powders were cold compacted at 600 MPa, and then sintered at 875 °C for 2 h under (hydrogen/nitrogen 1:3) atmosphere. A reference copper sample was also prepared by the same method to compare between the properties of pure copper and the carbon short fibers/copper composites. The phase composition, morphology, and microstructure of the prepared carbon short fibers/copper composite powders as well as the corresponding carbon short fibers/copper composites were investigated using X-ray diffraction analysis (XRD) and scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS), respectively. The density and the electrical resistivity of the sintered composites were measured. It was observed from the results that the density was decreased; however, the electrical resistivity was increased by increasing the carbon short fibers wt.%.
        4,300원
        105.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The composite PAN fibers which incorporated with CNTs and Titania were prepared by mean of wet spinning. These fibers were then pre-oxidized with microwave heating in an air atmosphere. A combination of characterizations was carried out to study the impact of nanoparticles fillers on the properties of as-spun fibers and their performance during the microwave pre-oxidation. The addition of an equal amount of fillers made obvious changes in the chemical and crystalline structure, consequently improves the strength, and this could lower the capability to creep over a wide range of temperatures in the subsequent processes. FTIR and NMR analyses results of the pre-oxidized fibers exhibited clear changes in the PAN structure, where the dehydrogenation reaction and the degree of cyclization were investigated. Additional confirmation of the occurrence of cyclization reaction was achieved by XRD and thermal analysis. According to the TGA results, the pre-oxidized CNT1/ Ti-PAN fibers exhibit greater thermal stability suggesting high carbon content and good quality could result in the dependent carbon fibers.
        4,200원
        106.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of the number of frozen-thawed ram sperm per single and double intra-cervical artificial insemination (AI) on fertility in ewes were studied. A total of 89 non-pregnant ewes were synchronized for oestrus with two doses of 100 μg PGF2α (Cloprostenol) 9 days apart. The ewes were randomly assigned to one of four groups; D200 (n = 23; double AI with 200 × 106 sperm), S200 (n = 24; single AI with 200 × 106 sperm), D100 (n = 24; double AI with 100 × 106 sperm) and S100 (n = 18; single AI with 100 × 106 sperm). Ewes were inseminated within 12 to 18 h for single AI and, within 10 to 12 h and 16 to 18 h for double AI after the onset of oestrus. The onset of oestrus ranged from 28 to 76 h (54.33 ± 1.28 h). The high percentage (29.2%) of ewes showed oestrus between 51 to 60 h. The non-return rates were highest in group D200 (56.5%) and differed significantly (p < 0.05) from group S100 (11.1%). No ewes were pregnant in group S100, and the pregnancy rates among the remaining groups did not differ. The mean gestation period was 152.8 ± 0.5 days and no difference was observed among the groups. The lambing and multiple birth rates were 100% in group D200. The single and twin lambing was highest in group D100 (33.3%) and group D200 (83.3%), respectively. Only one triplet lambing and the highest lambing size (2.2 ± 0.2) was recorded in group D200. In conclusion, double AI with 200 × 106 sperm showed comparatively most practical for achieving high pregnancy rates and lambing performances in Bangladeshi ewes under field conditions.
        4,000원
        107.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study aimed to investigate the conceptus-related changes during early pregnancy in the Black Bengal breed of goat. A total of 22 gravid genitalia of the Black Bengal goats were collected from local slaughterhouses. The crown-rump lengths (CRL) of the conceptuses were determined to estimate the gestational age (GA). The length and diameter of uterine horn and amniotic sac were measured, and volume of amniotic and allantoic fluid formed by individual conceptus were recorded. The results reveal that the CRL is positively correlated with GA of the conceptus (R2 = 0.89, p < 0.05); however, CRL was not influenced by number of conceptus. Both the left and the right uterine horn gradually increased in size with the advancement of pregnancy irrespective of conceptus number present in the horn. The size of the amniotic sac of conceptus gradually increased with the conceptus age but maintained spherical shape from 5 to 7 weeks of pregnancy. The amniotic fluid formed by individual conceptus rapidly increased from 5 weeks (3.4 ± 0.3 mL) to 7 weeks (21.0 ± 2.0 mL) and 9 weeks (111.5 ± 4.0 mL). The volume of allantoic fluid formed by individual conceptus was steadily increased until 7 weeks (60.0 ± 5.0 mL) and began to decline slowly thereafter (50.0 ± 5.0 mL at 9 weeks). Notably, there was no effect of conceptus number per pregnancy on individual amniotic and allantoic fluid volume. The cotyledons have first appeared on the allanto-chorionic surface from 4 to 5 weeks of pregnancy. The closed eye, nostril and hooves of the conceptus became visible at 7 weeks of pregnancy. The present study has shown the basic information on conceptus-related developmental changes during early pregnancy up to 9 weeks in Black Bengal goat.
        4,000원
        108.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Objectives: Free Water Protocols (FWPs) are implemented selectively because of mixed evidence on the benefits associated with their use. This retrospective study examines the implementation a long-standing clinical program and descriptively reports rehabilitation and quality care outcomes. Methods: Data were collected over 6 years (n = 575). Inpatient rehabilitation setting. Variables included in this study were age, medical diagnoses, rate of acute care hospital transfers, discharge destinations, length of time on FWP. Results: Cohort consisted of older adults (M = 68.43, SD = 15.11), with diagnosis of stroke (60.2%), brain injury (19.1%), spinal cord injury (7.3%), cardiac (1%), orthopedics (5%), other (13.1%). Acute care hospital transfers occurred in 6% as descriptively compared to national average (14%). Additionally, participants tolerated FWP for days (M = 14.1, SD = 14.4) and most went home following rehabilitation Discussion: This retrospective study concludes the feasibility of implementing a FWP in a rehabilitation facility and reports descriptive outcomes. Experimental research is required for conclusions to be made regarding effectiveness of the FWP for dysphagia.
        4,000원
        109.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the current study was to compare the effects of season and breed on the reproductive performance of male and female sheep using 12 rams and 318 ewes of Assaf and Awassi breeds under the seasonal environmental condition of United Arab Emirates for two years. The blood level of testosterone hormone was measured monthly. Semen was collected twice a month from each male using artificial vagina and evaluated for volume, motility, livability, abnormality and concentration. The scrotal circumference and thickness as well as the left testicular length, width, height and volume were measured at one-month intervals. The level of testosterone in Assaf breed was significantly higher in autumn than winter and summer. The scrotal circumference and thickness as well as the left testicular length were significantly higher in Assaf breed than Awassi breed. While, left testicular width and volume were significantly higher in Awassi breed than Assaf breed. Scrotal circumference which was higher in spring and summer than in autumn and winter season in both breeds. The SCC of semen was significantly higher in autumn than in other seasons in both breeds. The sperm abnormality was significantly higher in summer than other seasons in both breeds. The livability was significantly lower in summer in both breeds. Fecundity and prolificacy were significantly higher in Assaf than Awassi breed during autumn season. Assaf breed showed the superior reproductive performance in the autumn season when compared with Awassi breed in the same season and other seasons. The Assaf breed tolerated the climatic conditions in UAE and kept the litter size of 1.72 in comparison to Awassi breed which showed litter size of 1.09. in conclusion, the results showed the superiority of Assaf over Awassi breed and offer a good model of breeding with increased fecundity and prolificacy specially in autumn season.
        4,000원
        110.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.
        6,000원
        114.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study aims to use asphaltene particles (As) extracted from natural bitumen to synthesize activated carbon (ACAs). The asphaltene particles were mixed with a fixed weight of potassium hydroxide (KOH) as an activating agent, preheated to 600 °C, and then treated with 15% hydrofluoric acid (HF). The methylene blue (MB) 20 mg/l was used to determine the adsorption capacity of ACAs and reactivated carbon (RACAs). The morphology of ACAs and its components were characterized using scanning electron microscopy–energy dispersive X-ray (SEM–EDX) and Fourier-transform infrared spectroscopy (FTIR). The study included the application of adsorption isotherms Freundlich and Langmuir on the experimental data of the studied systems. The yield of ACAs was 92% of the raw material. The activated carbon displayed high adsorption capacity and can be reprocessed after reactivation using microwave radiation. The active surface area of ACAs is found to be 970 m2/g. The effectiveness and adsorption ability of ACAs and RACAs, as proven by its adsorption capacity (218.15 and 217.907 mg/g) for MB, demonstrate that ACAs and RACAs have a large external surface area and an extensive array of pores. The ACAs are most sensitive at 30 °C and neutral pH. The results also showed that the isotherms have a good fit to the experimented data.
        4,000원
        115.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Wood sawdust from an invasive arboreal species, Parkinsonia aculeata, and seeds from a tropical fruit of massive consumption, Pouteria sapota, were used as precursors for the development of activated carbons (ACs) directed to CO2 adsorption. Chemical activation employing KOH as activating agent and pre-established experimental conditions was applied. Main physicochemical properties of the ACs in relation to their CO2 adsorption performance were examined. The ACs developed from the wood sawdust and the seeds presented specific surfaces areas of 770 and 1000 m2 g−1, respectively, with their porosity development resulting essentially microporous (< 2 nm). They also showed a similar content of acidic surface groups, but basic functionalities of the former duplicated those of the latter. Maximum CO2 adsorbed at equilibrium (273 K and 100 kPa) was 5.0 mmol g−1 and 4.4 mmol g−1 for the samples derived from the sawdust and the seeds, respectively. On the other hand, CO2 adsorption capacities mimicking post-combustion conditions, as evaluated from thermogravimetric assays and breakthrough curves obtained in a packed-bed column, were approximately 1 mmol g−1, indicating a good CO2 adsorption performance for both ACs. Nevertheless, those derived from the wood sawdust with a notorious preeminence of micropores (~ 93%), narrower pore size distribution centered around 1 nm, and a higher content of basic functionalities than the ACs obtained from the seeds showed a relatively better performance. The CO2 removal capacity of the activated carbons was not noticeably affected after five CO2 adsorption–desorption cycles, with both samples almost keeping their initial CO2 adsorption capacity.
        4,000원
        116.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        스리랑카는 채소의 주년 생산에 적합한 기후를 갖고 있는 열대국가이다. 열대, 아열대 채소의 재배면적은 전체 농지(105,062 ha)의 약 3%이다. 지난 50년 동안 스리랑카에서 채소 육종에 관한 체계적인 연구가 이루어졌고 채소 부문은 지속적으로 증가하였다. 하지만 채소 육종, 재배 및 가공과 관련된 기술이 선진국에 비해 많이 뒤떨어져 있는 형편이다. 전통 육종법을 통해 개발된 다양한 농업적 형질을 가진 품종이 현재까지 스리랑카의 채소 생산에 이용되고 있지만 생명공학적 방법을 접목한 채소 품종 육종법의 중요성이 점차로 부각되고 있다. 본 논문은 스리랑카에서 중요한 채소 작물인 토마토, 고추류, 콩류, 가지 및 여주의 육종과 품종 현황을 소개하고 향후 스리랑카 육종 전망에 대해 논의하였다.
        4,000원
        117.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Assisted reproductive technologies (ART) merely depend on improving the oocyte maturation and their developmental competence to produce good quality embryos. Oocyte maturation passes through long and complex molecular steps starts from the early embryonic life and ends with sperm fertilization. Oocyte developmental competence can be attained by improving the nuclear and cytoplasmic mechanisms together with some epigenetic maturation. In this review, we highlight the cornerstones of oocyte maturation on both nuclear and cytoplasmic levels. Interfering or supporting these molecular mechanisms would help in the development of novel regulating agents for reproductive performance of humans and livestock species.
        4,000원
        118.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Environmental pollution remains a considerable health risk source all over the world; however, hazards are usually higher in developing countries. Iraq has long been suffering from the problem of pollution and how to treat pollution. Photocatalytic degradation has turned out to be most productive process for dye degradation. In this investigation, Rhodamine B (RhB), dye has been selected for degradation under visible light illumination. To address this issue, we fabricate erbium trioxide nanoparticles (Er2O3/NPs). Erbium trioxide nanoparticles are prepared and utilized for photo-catalytic degradation. The characterization of Er2O3/NPs is described and confirmed by utilizing of XRD (X-ray diffraction) and SEM (Scanning Electron Microscopy). The average size of Er2O3 nanoparticles is observed to be 16.00 nm. Er2O3/NPs is investigated for its ability of photo-catalytic degradation through certain selected parameters such as concentration and time. The methodological results show that the synthesized Er2O3/NPs is a good photo-catalytic for Rhodamine degradation.
        4,000원
        119.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The advance of information technology with governmental support allows researchers to utilize big data to conduct rigorous rehabilitation-related studies in both the United States and Korea. While big data research has been actively conducted in the United States, few Korean rehabilitation scientists currently conduct big data research. In this paper, we discuss the existing rehabilitation-related big data in Korea and introduce the current big data research trends in the United States. In addition, we provide potential research areas by discussing the previous big data studies in the United States, including 1) functional outcomes, 2) geographical variation, 3) linkage of a population-based cohort to hospital data, 4) cross-national comparison, and 5) scale development. We also discuss various statistical methods required in big data research and compare how these methods differ compared to the traditional research methods in rehabilitation research. Lastly, we discuss the importance of workforce development in rehabilitation-related big data research. We hope this paper will provide occupational therapy scientists and clinicians with practical and useful information about big data research and accelerate big data rehabilitation research communities in Korea.
        4,200원
        120.
        2019.12 구독 인증기관 무료, 개인회원 유료
        Fatigue is not a trivial issue and needs much attention. On the other hand, fatigue among seafarers could lead to accidents at sea due to their inability and ineffectiveness in carrying out their work. Some were caused by sleepiness and lack of vigour, which, could not only affect their safety but compromising on other seafarers as well. In this study, factors that cause fatigue among seafarers were examined analytically and their quantitative priorities were determined using Analytic Hierarchy Process (AHP) method. Additionally, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is used to identify the best alternatives in minimizing fatigue among seafarers. For this, data is collected through interview involving those working in academic and maritime industry with more than 5 years of experiences in dealing with seafarers. The AHP result shows that fitness is the main cause that could affect fatigue on seafarers’ reliability. Besides, TOPSIS result shows that a well-maintained shipboard is the best way in sustaining seafarers’ energy. In sum, fatigue among seafarers could influence on safety and may lead towards precarious health issue over a long-term.
        4,000원