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        검색결과 1,217

        421.
        2017.04 구독 인증기관·개인회원 무료
        The cowpea aphid Aphis craccivora Koch (Hemiptera: Aphididae) is an important pest on several species of legumes. We investigated the development periods and survivorship of A. craccivora nymph, and longevity and fecundity of A. craccivora adult. The study was conducted at five constant temperatures of 10, 15, 20, 25, and 30°C, respectively. The lower developmental threshold (LDT) and thermal constant (K) of A. craccivora nymph stage were estimated by linear regression. Higher temperature threshold (TH) and lower temperature threshold (TL) were calculated by biophysiological model. Developmental completion of A. craccivora nymph stage was described using a two-parameter Weibull distribution model. Life table parameters were estimated by the jackknife method.
        422.
        2017.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi are expected to play a role as great biological control agents in the global bio-pesticide market in the future. The first step is the collection of fungal isolates and it should be a platform for the development of highly effective biopesticides. In this work, we constructed a fungal library using a mealworm pathogenecity-based fungal collection method and further characterized some isolates with high virulence. A phylogenetic tree was generated, and of the isolates 17 isolates’ biological features were characterized, such as morphology, virulence against several insect, stability of conidia for heat, production of biologically active materials, such as enzymes. This work reports an attractive entomopathogenic fungal library including the information of effective isolates in pest management.
        423.
        2017.04 구독 인증기관·개인회원 무료
        Many turfgrass pests, Ectinohoplia rufipes, Exomala orientalis and Popillia quadriguttata, cause serious damage to grass fields in Korea. In this study, control of turfgrass pests using entomopathogenic fungi were investigated using Protaetia brevitarsis seulensis as an alternative insect. In a preliminary experiment, some Metathizium sp. showed ca. 60% virulence after 7 days exposure to the entomopathogenic fungi. Compared to the contact-exposure, overall a spray treatment showed lower control efficacy against P. brevitarsis seulensis. Furthermore, mortality of various developmental stages of P. brevitarsis seulensis was investigated under laboratory conditions. This work suggests that when treated with fungi mortality of P. brevitarsis seulensis was closely related with developmental stage. These results provide a basic information for the control of P. brevitarsis seulensis using entomopathogenic fungi
        424.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report our research on aluminum mirror optics for future infrared astronomical satellites. For space infrared missions, cooling the whole instrument is crucial to suppress the infrared background and detector noise. In this aspect, aluminum is appropriate for cryogenic optics, because the same material can be used for the whole structure of the instrument including optical components thanks to its excellent machinability, which helps to mitigate optical misalignment at low temperatures. We have fabricated alu- minum mirrors with ultra-precision machining and measured the wave front errors (WFEs) of the mirrors with a Fizeau interferometer. Based on the power spectral densities of the WFEs, we con rmed that the surface accuracy of all the mirrors satis ed the requirements for the SPICA Coronagraph Instrument. We then integrated the mirrors into an optical system, and examined the image quality of the system with an optical laser. As a result, the total WFE is estimated to be 33 nm (rms) from the Strehl ratio. This is consistent with the WFEs estimated from the measurement of the individual mirrors.
        3,000원
        425.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper reviews the legacy of the SPCIA Coronagraph Instrument (SCI) of which the primary scienti c objective is the characterization of Jovian exoplanets by coronagraphic spectroscopy in the infrared. Studies on binary shaped pupil mask coronagraphs are described. Cryogenic active optics is discussed as another key technology. Then approaches to observing habitable zones in exoplanetary systems with a passively-cooled space infrared telescope are discussed. The SCI was dropped in a drastic change of the SPICA mission. However, its legacy is useful for space-borne infrared telescopes dedicated for use in exoplanetary science in the future, especially for studies of biomarkers.
        3,000원
        426.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present the development of a spectral dispersion device for wideband spectroscopy for which the primary scienti c objective is the characterization of transiting exoplanets. The principle of the disperser is simple: a grating is fabricated on the surface of a prism. The direction of the spectral dispersion power of the prism is crossed with the grating. Thus, the prism separates the spectrum into individual orders while the grating produces a spectrum for each order. In this work, ZnS was selected as the material for the cross disperser, which was designed to cover the wavelength region, ⋋ = 0.6-13 μm, with a spectral resolving power, R ≥ 50. A disperser was fabricated, and an evaluation of its surface was conducted. Two spectrometer designs, one adopting ZnS (⋋ = 0.6-13 μm, R ≥ 300) and the other adopting CdZnTe (⋋ = 1-23 μm, R ≥ 250), are presented. The spectrometers, each of which has no moving mechanical parts, consist simply of a disperser, a focusing mirror, and a detector.
        3,000원
        427.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present project updates of the next-generation infrared space mission SPICA (Space Infrared Tele- scope for Cosmology and Astrophysics) as of November 2015. SPICA is optimized for mid- and far-infrared astronomy with unprecedented sensitivity, which will be achieved with a cryogenically cooled (below 8 K), large (2.5 m) telescope. SPICA is expected to address a number of key questions in various fields of astrophysics, ranging from studies of the star-formation history in the universe to the formation and evolution of planetary systems. The international collaboration framework of SPICA has been revisited. SPICA under the new framework passed the Mission Definition Review by JAXA in 2015. A proposal under the new framework to ESA is being prepared. The target launch year in the new framework is 2027/28.
        4,000원
        428.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Modelling and tting the spectral energy distribution (SED) of galaxies or regions of galaxies is one of the most useful methods available to the astronomer nowadays. By modelling the SEDs and comparing the models to the observations, we can collect important information on the physical processes at play in the formation and evolution of galaxies. The models allow to follow the evolution of the galaxies from their formation on. The versatility of code is crucial because of the diversity of galaxies. The analysis is only relevant and useful if the models can correctly reproduce this diversity now and across (as best as possible) all redshifts. On the other hand, the code needs to run fast to compare several million or tens of millions of models and to select the best (on a probabilistic basis) one that best resembles the observations. With this important point in mind, it seems logical that we should efficiently make use of the computer power available to the average astronomer. For instance, it seems difficult, today, to model and fit SEDs without a parallelized code. We present the new Python version of CIGALE SED fitting code and its characteristics. CIGALE comes in two main avours: CIGALE Classic to fit SEDs and CIGALE Model to create spectra and SEDs of galaxies at all redshifts. The latest can potentially be used in conjunction with galaxy evolution models of galaxy formation and evolution such as semi-analytic ones.
        3,000원
        429.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two species of the minuta-subgroup within the oncaeid copepod genus Triconia Böttger-Schnack, 1999 collected in the equatorial Pacific Ocean are newly recorded. A female T. minuta (Giesbrecht, 1893 [“1892”]) and both male and female T. umerus (Böttger-Schnack and Boxshall, 1990) from the northeast equatorial Pacific are redescribed with the comparison of its morphological details, which differs from previous studies, in terms of the larger body size, the length to width ratio of the genital double-somite, the relative length of the outer basal seta on P5, and the ornamentation of the appendages. The characters, which are used for identification, such as the length ratio of the outer subdistal and outer spine versus the distal spine on P3-P4, and the outer spine length of the middle exopodal segment on P3 and P4 are reported for the first time. Information on the variations in the endopodal spine lengths of swimming legs 2-4 is also provided for T. minuta and T. umerus, with the summary of the wide zoogeographical distribution of these two species.
        5,400원
        430.
        2017.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The BCBJ (Back Contact and Back Junction) or back-lit solar cell design eliminates shading loss by placing the pn junction and metal electrode contacts all on one side that faces away from the sun. However, as the electron-hole generation sites now are located very far from the pn junction, loss by minority-carrier recombination can be a significant issue. Utilizing Medici, a 2-dimensional semiconductor device simulation tool, the interdependency between the substrate thickness and the minority-carrier recombination lifetime was studied in terms of how these factors affect the solar cell power output. Qualitatively speaking, the results indicate that a very high quality substrate with a long recombination lifetime is needed to maintain the maximum power generation. The quantitative value of the recombination lifetime of minority-carriers, i.e., electrons in p-type substrates, required in the BCBJ cell is about one order of magnitude longer than that in the front-lit cell, i.e., 5 × 10−4 sec vs. 5 × 10−5 sec. Regardless of substrate thickness up to 150 μm, the power output in the BCBJ cell stays at nearly the maximum value of about 1.8 × 10−2 W·cm−2, or 18 mW·cm−2, as long as the recombination lifetime is 5 × 10−4 s or longer. The output power, however, declines steeply to as low as 10 mW·cm−2 when the recombination lifetime becomes significantly shorter than 5 × 10−4 sec. Substrate thinning is found to be not as effective as in the front-lit case in stemming the decline in the output power. In view of these results, for BCBJ applications, the substrate needs to be only mono-crystalline Si of very high quality. This bars the use of poly-crystalline Si, which is gaining wider acceptance in standard front-lit solar cells.
        4,000원
        431.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cobalt was electrodeposited onto chemical vapor deposition (CVD) graphene/Si/SiO2 substrates, during different time intervals, using an electrolyte solution containing a low concentration of cobalt sulfate. The intention was to investigate the details of the deposition process (and the dissolution process) and the resulting magnetic properties of the Co deposits on graphene. During and after electrodeposition, in-situ magnetic measurements were performed using an (AGFM). These were followed by ex situ morphological analysis of the samples with ΔtDEP 30 and 100 s by atomic force microscopy in the non-contact mode on pristine CVD graphene/SiO2/Si. We demonstrate that it is possible to electrodeposit Co onto graphene, and that in-situ magnetic measurements can also help in understanding details of the deposition process itself. The results show that the Co deposits are ferromagnetic with decreasing coercivity (HC) and demonstrate increasing magnetization on saturation (MSAT) and electric signal proportional to remanence (Mr), as a function of the amount of the electrodeposited Co. It was also found that, after the end of the dissolution process, a certain amount of cobalt remains on the graphene in oxide form (this was confirmed by X-ray photoelectron spectroscopy), as suggested by the magnetic measurements. This oxide tends to exhibit a limited asymptotic amount when cycling through the deposition/dissolution process for increasing deposition times, possibly indicating that the oxidation process is similar to the graphene surface chemistry.
        4,000원
        432.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Vinca alkaloids from plant Vinca minor have been investigated for their effects of tyrosinase inhibition, stimulation of ROS generation and increasement of cell migration activity. The methanolic crude extract and the water-soluble fraction exhibited IC50 value of 3.1 mg/mL and 2.1 mg/mL. Vinca minor extract treatment significantly increased ROS levels in HaCaT cells, in a concentration-dependent manner. Treatments of Vinca minor extract led to increase wound closure when compared with non-treatment. Low dose (0.1% or 0.3%) of extracts have not significantly affected, compared with that in controls. By contrast, 0.5% extract have dramatic effect on wound healing activity of keratinocytes. Effects of Vinca minor extract in a filter-based cell mobility assay appear similar to that of wound closure assay, which suggests that the Vinca minor extract have wound healing effects on skin.
        4,000원
        433.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The concern over beauty is increasing as the importance of appearance is becoming more prominent. Accordingly, the importance of studying beauty is now apparent. The purpose of this study is to analyze existing beauty-related research in order to assess current trends in beauty-related studies. Materials were collected from the master’s theses and academic journals from 1997 through 2016. In addition, 81 beauty-related papers were selected and classified into 3 categories according to their subjects and content. There were 19 hair attitude papers, 52 papers about make-up and skincare, and 10 papers on cosmetic surgery. Each type was divided into detailed themes according to the study theme and its number was grasped. Consequently it was classified into 9 themes about the attitude toward hair and the relevant variable study, 10 themes about the attitude toward hair style and relevant variable study, 24 themes about the make-up attitude and relevant variable study, 28 themes about the skin care attitude and relevant variable study, and 10 themes about the cosmetic surgery attitude and relevant variable study. The results revealed that academic concern about beauty sharply increased starting in 2005. Moreover, we determined that the methodologies used in hair and make-up studies were sound and detailed, while cosmetic surgery studies were more inconsistent and poorly analyzed. Thus cosmetic surgery should be further researched in a more standardized and thorough manner. This review of attitudes toward beauty will serve as a basis for follow-up studies that employ meta-analyses to draw more quantitative conclusions by aggregating many more study results.
        5,700원
        434.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this research was to evaluate the effects of two different feeding systems on blood metabolites in Holstein heifers and analyze the economic impacts of the feeding systems. The following two experiments were conducted to investigate the effects of feeding system on blood metabolite changes in Holstein heifers and analyze the economic impacts of the two systems. In experiment 1, the effects of two different feeding systems on cortisol, progesterone, and estradiol in Holstein heifers were examined. In experiment 2, the effects of two different feeding systems on the body weights of Holstein heifers and profitability of the two feeding systems were studied. Results showed that the pasture-raised heifers showed significantly decrease in the levels of blood cortisol (p<0.05) and increases in the levels of progesterone and estradiol (p>0.05) when compared with heifers raised in indoor feeding system. The average daily gain was significantly higher (p<0.05) in indoor-raised heifers (0.73 kg/day) as compared to pasture-raised heifers (0.58 kg/day). Also, 25.2% more profits were obtained from the pasture feeding system as compared to the indoor feeding system. These results together would be useful in the investigation of feeding system and growth performance in dairy cattle.
        4,000원
        435.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Disinfectant-filled footbaths are the most commonly used infection control measures on livestock farms. The purpose of this study was to evaluate the efficacy of six commercial disinfectants, as used in footbaths on farms, for reducing Salmonella Typhimurium contamination of footwear. When used at the recommended concentrations, most disinfectants showed over 91% reduction efficacy in absence of organic matter. The greatest reductions were seen with oxidizing agents including potassium peroxymonosulfate-based products and sodium dichloroisocyanurate. These results suggest that disinfectant footbaths could be useful for reducing bacteria; however, footbaths should not be relied upon as the only method of controlling infectious pathogens. General good hygiene practice, for example cleanliness of boots, should be emphasized.
        3,000원
        436.
        2016.12 구독 인증기관 무료, 개인회원 유료
        The interest in convenience food has increased over the years. Many researchers have tried to discover what factors affect the consumption of convenience food. Despite the diversity of studies, few studies emphasize a household’s income. The aim of this article is to identify the different consumption patterns between upper, middle, and lower income brackets. Generally, households with higher income consumed more convenience food or the relationship was not significant. However, many convenience foods are regarded as nutritionally unbalanced and have a lower quality. So, the hypothesis cannot be easily confirmed because there are tradeoffs not only between health, as nutrition balance and cost, but also health and convenience. Thus, there is a need to indicate the divergent attributes of buying convenience food in a distinct income group. In addition, the convenience food is subdivided into two distinct categories: convenience food as a substitution for a whole meal (unhealthy) and substitution as part of a diet (healthy). We found that higher income groups purchase healthier convenience food while lower income groups purchase unhealthier convenience food. Also there are distinct attributes that influence the consumption of healthy and unhealthy convenience food.
        4,000원
        437.
        2016.10 구독 인증기관 무료, 개인회원 유료
        Determining the infection history of living organisms is essential for understanding the evolution of infection agents with their host, particularly for key aspects such as immunity. Viruses, which can spread between individuals and often cause disease, have been widely examined. The increasing availability of fish genome sequences has provided specific insights into the diversity and host distribution of retroviruses in fish. The shortspine spurdog (Squalus mitsukurii ) is an important elasmobranch species; this medium-sized dogfish typically lives at depths of 100~500 m. However, the retroviral envelope polyprotein in dogfish has not been examined. Thus, the aim of the present study was to identify and analyze the retroviral envelope polyprotein in various tissues of dogfish. The 1334-base pair full-length novel cDNA of dogfish envelope polyprotein (dEnv) was obtained by 3' and 5'-rapid amplification of cDNA end analysis from S. mitsukurii. The open reading frame showed a complete coding sequence of 815 base pairs with a deduced peptide sequence of 183 amino acids that exhibited 34~50% identity with other fish and bird species. It was also expressed according to reverse transcription and real-time polymerase chain reaction in the kidney, liver, intestine, and lung, but not in the gill. This distribution can be assessed by identifying and analyzing endogenous retroviruses in fish, which consists of three main genes: gag, pol and env. Dogfish envelope polyprotein sequence is likely important in evolution and induces rearrangements, altering the regulatory and coding sequences. This is the first report of the identification and molecular characterization of retroviral envelope polyprotein in various tissues of S. mitsukurii.
        4,000원