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        검색결과 630

        41.
        2023.07 구독 인증기관 무료, 개인회원 유료
        A new type of food created in laboratories – lab grown meat (LGM) is an alternative to traditional animal farming and attracting attention of media, industry experts and consumers. Why is this new product so controversial? It is claimed that cell-based meat production is more environmentally friendly, ethical and sustainable than traditional methods that involve animals. Hence, being less harmful and potentially slowing down environmental degradation that leads to climate change. However, consumers have concerns regarding product quality, sourcing of cells used for production and use of growth serums. So many differing views are present, even before LGM is introduced as a marketable product. This paper examines what drives public discourse regarding how this new industry can be regulated, technology and how social media posts, fake news and publicly available rhetoric address consumer concerns and consumer acceptance regarding this new food category.
        4,000원
        42.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Wide-Angle Polarimetric Camera (PolCam) is installed on the Korea’s lunar orbiter, Danuri, which launched on August 5, 2022. The mission objectives of PolCam are to construct photometric maps at a wavelength of 336 nm and polarization maps at 461 and 748 nm, with a phase angle range of 0◦–135◦ and a spatial resolution of less than 100 m. PolCam is an imager using the push-broom method and has two cameras, Cam 1 and Cam 2, with a viewing angle of 45◦ to the right and left of the spacecraft’s direction of orbit. We conducted performance tests in a laboratory setting before installing PolCam’s flight model on the spacecraft. We analyzed the CCD’s dark current, flat-field frame, spot size, and light flux. The dark current was obtained during thermal / vacuum test with various temperatures and the flat-field frame data was also obtained with an integrating sphere and tungsten light bulb. We describe the calibration method and results in this study.
        4,000원
        43.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This work presents four high-amplitude variable YSOs (≃3 mag at near- or mid-IR wavelengths) arising from the SPICY catalog. Three outbursts show a duration that is longer than 1 year, and are still ongoing. And additional YSO brightened over the last two epochs of NEOWISE observations and the duration of the outburst is thus unclear. Analysis of the spectra of the four sources confirms them as new members of the eruptive variable class. We find two YSOs that can be firmly classified as bona fide FUors and one object that falls in the V1647 Ori-like class. Given the uncertainty in the duration of its outburst, an additional YSO can only be classified as a candidate FUor. Continued monitoring and follow-up of these particular sources is important to better understand the accretion process of YSOs.
        4,000원
        44.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.
        5,100원
        45.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated durian (Durio zibethinus) peels to produce powdered activated carbon (DPAC). The influence of process variables such as carbonization temperature, activation time, contact time, CO2 flow rate, and adsorption dosage was optimized using response surface methodology (RSM). A six-factor and two levels Box–Behnken design (BBD) was used to optimize the parameters. The independent variables were activation temperature (°C), duration (min), CO2 flow rate during the activation process (L/min), irradiation of adsorbent (kGy), irradiation duration (min), and adsorbent dosage (g) while phenol removal (mg/L) was the dependent variable (response). Following the observed correlation coefficient values, the design was fitted to a quadratic model (R2 = 0.9896). The optimal removal efficiency (97.25%) was observed at an activation temperature of 900 °C, activation time of 30 min, CO2 flow rate of 0.05 L/min, irradiation dose of 100 kGy, contact time of 35 min and adsorption dosage of 0.75 g. The optimal DPAC showed a BET surface of 281.33 m2/ g. The removal efficiency was later compared with a commercially available activated carbon which shows a 98.56% phenol removal. The results show that the durian peel could be an effective precursor for making activated carbon for phenol removal, and irradiation can significantly enhance surface activation.
        4,000원
        46.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work reports the fabrication of a flexible Photodetector (PD) using Carbon Dots (CDs)/Polymer composite for Deep UV (DUV) photodetection. The CDs have been prepared using a simple and inexpensive heating process. The syncretic studies reveal the disordered graphitic core with surface functional groups and the excitation-dependent character of CDs. The synthesized CDs are stabilized via Poly Vinyl Alcohol (PVA) through a synergistic effect and investigated for different compositions (2–10 weight %) of CDs. The CDs/PVA composites shows improved absorbance at 208 and 335 nm compared to pure CDs owing to the bonding between them. This advantageous property of high absorption and photo response in the DUV region is utilized by employing CDs/PVA composite as a photo-sensing layer on the ITO-coated PET substrate in the PD. The performance of the PD was measured under dark, short (254 nm) and long (365 nm) UV region. Among all the compositions, 4% CDs/PVA PD exhibits superior performance in terms of high photo-to-dark current ratio (IPh/Id), responsivity and detectivity. The PD functioning and other parameters are discussed in detail and reported.
        4,200원
        49.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Subunit vaccines are being developed as a potential therapy for preventing microbial pathogen infection. In this study, the immunogenicity of recombinant Brucella (B.) abortus Fe/Mn superoxide dismutase (rFe/Mn SOD) protein as a subunit vaccine against B. abortus was investigated in BALB/c mice model. Brucella Fe/Mn SOD gene was cloned into a pcold-TF DNA vector. The bacterial recombinant protein was expressed using the Escherichia coli DH5α strain with a size of 82.50 kDa. The western blotting assay showed that rFe/Mn SOD reacted with Brucella-positive serum, indicating the potential immunoreactivity of this recombinant protein. After the second and third vaccinations, the peripheral CD4+ T cell population was increased significantly in the rFe/Mn SOD-immunized mice group compared to the PBS control group. Moreover, immunization of this recombinant protein increased the CD4+ T cell population from the first vaccination to the third vaccination. Meanwhile, the CD8+ T cells were slightly enhanced after the second vaccination compared to the first vaccination and compared to control groups. Fourteen days after the bacterial infection, the splenomegaly and the number of bacteria in the spleen were evaluated. The result showed that both rFe/Mn SOD and positive control RB51 decreased the bacterial replication in the spleen and the splenomegaly compared to control groups. Altogether, these results suggested that rFe/Mn SOD could induce host immunity against B. abortus infection.
        4,000원
        51.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, we report a direct preparation of a few-walled carbon nanotube (FWCNTs) and NiMgAl composites namely FWCNT-NiMgAl by pyrolysis of waste high-density polyethylene (HDPE) plastic at 800 °C with NiMgAl-layered double hydroxide (LDH) as catalysts. The composite formation is carried out in a single step using our lab-developed pyrolysis reactor. The NiMgAl-LDH catalyst was prepared by co-precipitation method and the FWCNTs were grown on the NiMgAl-LDH catalyst with FWCNT yield of 10% and FWCNT-NiMgAl composite yield of 55% whose quality is determined by Raman ID/IG ratio of 2.57. The average outer and inner diameter of the FWCNT are found to be 5.5 nm and 2.9 nm, respectively, from TEM and 2.92 nm from the outer RBM (radial breathing mode) band, which indicates the formation of a few-walled CNTs. FWCNT-NiMgAl is used for the fabrication of flexible supercapacitor electrodes on a polyethylene terephthalate (PET) sheet which achieved a specific capacitance of 432 Fg− 1 in a wide potential range (ΔV = 2) at a scan rate of 5 mV s− 1 in 2 M KOH electrolyte with a high energy density of 240 Wh kg− 1, whereas NiMgAl displayed a capacitance of 200 Fg− 1 with an energy density of 111 Wh kg− 1. The diffusion-type charge storage mechanism (pseudocapacitance) is found to be dominant with contributions of 73.2% and 69.75% for NiMgAl and FWCNT-NiMgAl, respectively. The highest specific capacitance and energy density are obtained for NiMgAl in 2 M KCl and for FWCNT-NiMgAl in 2 M NaOH electrolytes. However, the largest potential window is observed in KOH electrolyte for both NiMgAl and FWCNT-NiMgAl with value of ΔV = 2 V. The electrode material shows good stability in acidic electrolytes and also shows good capacitive stability at high frequencies maintaining a phase angle of 70°. The present work is a novel approach to fabricate low-cost multifunctional carbon composite nanomaterials and will contribute to the research on low-cost waste-derived CNT composite preparation and its application in flexible energy storage devices.
        5,100원
        52.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An electrical double-layer capacitor is fabricated with biomass-derived activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs), which are synthesized from Pongamia pinnata fruit shell and its seed oil, respectively. The activated carbon is produced by the chemical activation process at varying carbonization temperatures from 600 to 900 °C for 5 h at a rate of 10 min in an N2 atmosphere. The surface area of activated carbon and MWCNTs is 1170 m2 g− 1 and 216 m2 g− 1, respectively. The total pore volumes of activated carbon and MWCNTs are 1.51 cm3 g− 1 and 0.5907 cm3 g− 1, respectively. The as-prepared AC and MWCNTs are characterized by surface area analysis Brunner–Emmett–Teller method (BET), X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopic analysis, field emission scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. The electrochemical performances of AC-AC, MWCNTs-MWCNTs and AC-MWCNTs (25:75) symmetric electrodes are studied by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The AC-MWCNTs (25:75) single electrode performance is also studied in two different electrolytes, such as 0.5 M Na2SO4 and 0.5 M H2SO4. The fabricated AC-MWCNTs (25:75) symmetric supercapacitor cell exhibits excellent electrochemical performance in 0.5 M Na2SO4. It shows a specific capacitance of 55.51 Fg− 1, energy density 4.852 Wh Kg− 1 and power density of 199.18 W Kg− 1 at a current density of 1 Ag− 1 in the voltage window of 0–1.8 V. The AC-AC and AC-MWCNTs (25:75) symmetric supercapacitor electrodes show outstanding performance.
        6,300원
        53.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alzheimer's disease (AD) is one of the most common forms of dementia, affecting more than 50 million people globally. The onset of AD is linked to age, smoking, obesity, hypercholesterolemia, physical inactivity, depression, gender, and genetics of an individual. The accumulation of Aβ peptides and neurofibrillary tangles (NFTs) in the brain is one of the critical factors that lead to AD, which is known to disrupt neuronal signaling and causing neurodegeneration. As per the current understanding, inhibiting the accumulation of Aβ peptides and NFTs is crucial in the management/treatment of AD. Latest research studies show that nanoparticles have the potency of improving drug transport across the blood–brain barrier easily. Specifically, graphene quantum dots (GQDs), a type of semiconducting nanoparticles, have been established as effective inhibitors for blocking the aggregation of Aβ peptides. The small size of GQDs allows them to pass through the blood– brain barrier with ease. Moreover, GQDs have fluorescence properties, which can be used to detect the concentration of Aβ in vivo. In recent years, compared to other carbon materials, the low cytotoxicity and high biocompatibility of GQDs, give them an advantage in the suitability and clinical research for AD. In this manuscript, we have discussed the role of different types of nanoparticles in the transportation of encapsulated or co-assembled compound drugs for the treatment of AD and importantly, the role of GQDs in the diagnosis and management/treatment of AD.
        4,600원
        54.
        2022.10 구독 인증기관·개인회원 무료
        Radioactive waste containing cellulosic materials such as cotton, paper and wood are being disposed in Low-and intermediate-level radioactive waste disposal site in Gyeongju. Cellulose has recently emerged great issue in terms of disposal site safety as it can be decomposed into an organic complex compound, ISA (isosaccharinic acid), under strong alkali conditions (pH 12.5 or higher) formed by the hydrated cement, to accelerate the mobility of the radionuclides in the disposal facility. However, in Korea, there are insufficient criteria for confirming the suitability for disposal of low-and intermediatelevel radioactive wastes including cellulose, and there is no specific method for evaluating the total amount of waste to confirm the suitability of disposal. Therefore, the method of SKB (Swedish Nuclear and Fuel Management Company), which has established acceptance criteria related to the physicalchemistry safety of cellulose, is analyzed to suggest a method for deriving the amount of cellulosecontaining waste disposal. Cellulose, an organic complexing agent, is an important consideration for safety case at the Swedish low-and intermediate-level radioactive waste disposal site SFR. SKB calculated the amount of cellulose generated by separately labeling cellulose-containing wastes of 1-2BMA, Silo and 1BTF (SKB 2013). BLA, a low-level radioactive waste disposal facility, is not considered due to its low radionuclide inventory (~0.2% of SFR’s total radionuclide inventory, SKB 2013). To calculate the amount of cellulose that can be disposed of, information on the mass and volume of hydrated cement (concrete waste, cement solidification waste, disposal container, grouting, disposal shed), the concentration of ISA absorbed in the hydrated cement, and the concentration of ISA dissolved in the groundwater which were used. In addition, the total disposable amount was calculated using the cellulose degradation rate, composition ratio, and the cellulose containing waste volume.
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