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The optical, plasmonic, and imaging performance of an infra-red polarized system exceeds that of a conventional infra-red detector due to its high resolution and precision.

Sclerotinia rot was occurred on the leaf and stem of Peucedanum japonicum Thunb. in greenhouse field of Pohang city of Gyeongbuk province in Korea. The typical symptom of the disease was light brown spot and tipburn on infected leaves. The colony of the isolated fungus was white to light gray in color. Asci were cylindrical shape and 75‒240×5.9‒17.3 μm in size. Apothecia were cup-shaped with numerous asci and 0.5‒0.9 cm in size. Ascospores were aseptate and ellipsoid in shape, and 8.4‒10.7×4.8‒5.8 μm in size. Sclerotia formed on the plants and potato dextrose agar medium were globose to irregular in shape and black in color. Partial sequencing of rDNA of this isolate showed that it was 100% consistent with that of Sclerotinia sclerotiorum. It was confirmed that the same lesion was formed by reinoculating this pathogen on a healthy P. japonicum Thunb. and the same strain was isolated. This is the first report on the Sclerotinia rot of P. japonicum Thunb. caused by S. sclerotiorum in Korea.

Thermally tunable extraordinary terahertz transmission in a hybrid metal–vanadium dioxide ( V O 2 ) metasurface is numerically demonstrated. The metasurface consists of a metal sheet perforated by square loops, while the loops are connected with strips of V O 2 . The frequency and amplitude of the transmission resonance are modulated by controlling the conductivity of V O 2 . For a y -polarized incident field, the resonance transmission peak redshifts from 0.88 to 0.81 THz upon insulator-to-metallic phase transition of V O 2 . For an x -polarized incident field, the transmission resonance at 0.81 THz is observed in the insulator phase. However, in the metallic phase of V O 2 , the electromagnetic field is effectively reflected in the 0.5–1.1 THz range with a transmission level lower than 0.14. The proposed metasurface can be utilized as a terahertz modulator, reconfigurable filter, or switch.

본 논문은 2020년 이후 발생한 북한 관련 가짜뉴스의 생산 및 유통과정을 살펴본 뒤 남북관계에 미치는 현황을 진단하여 대응방안을 제시하는 데 목적이 있다. 북한 관련 가짜뉴스는 누구나 의도성을 가지고 왜곡하여 전파할 가능성이 높다는 데 우려가 존재한다. 북한 관련 가짜뉴스로 인해 북한에 대한 왜곡된 인식의 고착화, 남남갈등 확산 등의 사회적 문제가 나타날 수 있다. 이로 인해 정부 차원에서 합리적 대북정책을 추진하는 장애 요인으로 작용하여 남북관계의 경색을 초래할 위험이 나타날 수 있다. 또한 코리아 리스크의 확산으로 인한 국제정치적, 경제적 악영향이 발생할 위험이 있다는 점도 나타날 수 있다. 이러한 위험요소들을 해소하기 위해서는 북한자료의 개방, 팩트체크 전담기구 및 연구소 설립, 북한 관련 전문인력 양성 등의 사회적 대응방안이 요구된다. 법적 규제방안으로 다른 가짜뉴스의 대응과 같이 북한 관련 가짜뉴스에서도 정보통신망법 및 방통위 정보통신심의규정의 엄격한 적용과 개별입법 차원에서 법률안을 개정할 필요가 있다. 최근 북한 관련 가짜뉴스가 유튜브, SNS 등 뉴미디어의 등장으로 급속히 광범위하게 확산되는 특징이 있다는 점에서 신속히 법적, 사회적 대응방안을 마련하고 시행할 필요가 있다.

Although, quantum dots (QDs) of two-dimensional (2D) molybdenum disulfide (MoS

An efficient and experimentally straightforward method for the synthesis of 2-amino-4-phenylbenzo [4,5] imidazo [1,2-a] pyrimidine-3-carbonitrile derivatives has been developed via one pot three-co...

The structural and optical properties of InAsxP1-x metamorphic buffers grown by metal–organic chemical vapor deposition on InP (100) substrates have been investigated. High-resolution X-ray reciprocal space mapping around the (115) InP lattice point reveals that the strain relaxations of the InAsxP1-x with x = 0.5, 0.55, and 0.7 are 98%, 92%, and 96%, while the lateral correlation lengths are 17, 62, and 28 nm, respectively. The optical bandgap energy of the InAsP derived from photoreflectance (PR) measurements decreases from 0.819 to 0.621 eV at 300 K when increasing As composition from x = 0.5 to 0.7. The bowing parameter for the optical bandgap of the InAsP is increased with increasing As composition, which is attributable to the increased spontaneous CuPt-type ordering in InAsP. It is found from the excitation power-dependent PR measurement that the InAsxP1-x layers have different degrees of the bandgap redshift due to the reduced thermal conductivity caused by crystal imperfections generated during the strain relaxation process.

Green-emitting Cs4PbBr6 nanocrystals were synthesized by the water-assisted solid-state reaction method for the first time. Although CsPbBr3 phases were observed in the X-ray diffraction (XRD) patterns of the perovskite nanocrystal samples as impurities, the XRD patterns of the samples could be well indexed to the trigonal Cs4PbBr6 structure. The Cs4PbBr6 perovskite nanocrystals showed a bright green emission with a narrow emission band centered at 518 nm with a full width at half-maximum of 26 nm. The photoluminescence quantum yield (PLQY) of the Cs4PbBr6 nanocrystals was 36.8%. The Cs4PbBr6 nanocrystal powder showed excellent durability at 85 °C and 85% humidity for 24 h, and retained 82% of the initial PL intensity. The Cs4PbBr6 nanocrystal film light-emitting diode chip showed a luminous efficacy of 30.6 lm Wrad−1.

A new and practical synthetic approach to construct 2-aryl-quinoline derivatives has been described through the sequential Aza-Henry (Nitro-Mannich) reaction using readily available 2,3-dihydro-1H-inden-5-amines, aldehydes and nitroalkanes under one-pot solvent-free reaction conditions using TsOH·H2O as the sustainable catalyst. In this regioselective approach, we described a cascade that proceeds through a sequential imine formation/Aza-Henry reaction/cyclization/denitration/rearrangement followed by oxidative aromatization to afford diverse 2-aryl-quinolines. This approach features large substrate scope, good functional group tolerance, mild reaction conditions and excellent yields with gram scale synthetic utility.

We examined several types of GaAs/Al $$_{0.3}$$ Ga $$_{0.7}$$ As quantum dots (QDs) grown by the droplet epitaxy (DE) technique. Using comparative optical analyses using multi-oscillator models, we investigated the individual exciton–phonon coupling channels of several QD types with different temperature dispersions. Each phonon dispersion was calculated for up to three different coupled modes in a phonon field. Nanoscale phonon engineering can exploit the dynamics of exciton–phonon interactions for the design of efficient acousto-excitonic devices and engineered QD single-photon sources.

While regulations are being strengthened to prevent air pollution from ships in Korea and other countries, the Korean government has passed the Eco-Friendly Ship Act, which is effective from 1 Janu...

This paper reports the structural optimization and the temperature-dependent electrical characterization of GaAs single-junction solar cells (SJSCs) based on the p+-n-n+ junction structure. First, the effects of the p+-Al0.9Ga0.1As window layer were investigated using illuminated current density-voltage (LJ−V) and photoreflectance measurements to determine the optimal structure of the SJSC. In addition, the thickness and the doping concentration of different layers, such as the p+-GaAs emitter and the n-GaAs base layers, were optimized, leading to the maximum efficiency (η = 21.53%). These results show that the device performance can be improved further when compared to the world record (η = 28.8%). Second, the capacitance-voltage (C−V) and the dark J−V characteristics of a GaAs SJSC with the optimal structure were investigated over the temperature range from 100 to 300 K. As the temperature was increased, both the junction capacitance at zero voltage (Cj0) and the carrier concentration in the active region (Nd) increased while the depletion width (W) and the built-in potential (Vbi) decreased due to purely thermal effects. Among the SC parameters obtained from the dark J−V curves, the ideality factor (n) decreased from 4.38 to 1.70 and the reverse saturation current density (J0) increased from 6.05 × 10 −12 to 4.26 × 10 −10 A/cm2 with increasing temperature. These values at 300 K were similar to those simulated theoretically and reported previously for high-quality GaAs junction diodes.

This paper reports the simultaneous synthesis of gold nanoparticles (AuNPs) with a spherical and stable structure using microbial fuel cell (MFC) biofilms. The green, facile, chemical stabilizers and capping-agent free AuNPs synthesis allow the binder-free in situ decoration of AuNPs on MFC anode electrode with the help of special interactions of biofilm. The MFC with AuNPs decorated carbon foam anode electrode produced 62.5% higher (46.37 Wm-3) power density than that of the MFC equipped with plain carbon foam anode (control). The AuNPs facilitated the good adhesion of bacteria, amplified the conductivity, and reduced the internal resistance, resulting in improved overall MFC performance. In addition, the peroxide-mimicking activity was evaluated and the MFC-synthesized AuNPs exhibited significantly higher peroxidase mimicking activity than the chemically synthesized AuNPs, thereby, allowing the easy and rapid colorimetric detection of hydrogen peroxide with a detection limit of 20 uM.

In this study, we investigated the electrical and structural properties of sulfur-graded Cu2ZnSn(S,Se)4 (CZTSSe) thin films grown using a modified two-step process according to the annealing temperature. The sulfur content of the CZTSSe thin film was increased with annealing temperature and a Zn(S, Se) secondary phase was observed at temperatures higher than 500 °C. The Raman spectrum of the CZTSSe thin film shifted continuously toward the high frequency direction with increasing S content and the Cu2SnSe3 (CTSe) secondary phase was present below 440 °C. From the results of dimpling Raman spectroscopy and scanning transmission electron microscopy (STEM) line scanning, we confirmed that the S content increased gradually from the Mo back contact to the surface of the CZTSSe thin film. Finally, a sulfur-graded CZTSSe thin film with a photovoltaic efficiency of 7.03% was fabricated by optimizing the annealing temperature.