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Direct Z-scheme designs perform well in light-to-fuel conversion. Here, an active and stable ternary Z-scheme core-shell heterojunction for photocatalytic hydrogen evolution (PHE) is fabricated consisting of hexagonal 2D α-Fe2O3 (as photocatalyst II) and 2D nitrogen-doped graphene (NGr as photocatalyst I) functionalized with the Pt single-atoms (SAs) cocatalyst. Under visible light, the 2D/2D α-Fe2O3 @NGr3[sbnd]PtSAs (NGr shell thickness of 3 nm and Pt loading of 0.5 wt%) achieves a remarkable PHE of 6.4 µmol mgcat−1 h–1, which is 16.4- and 3.28-times higher than those of free NGr (0.39 µmol mgcat−1 h–1) and binary α-Fe2O3 @NGr3 (1.95 µmol mgcat−1 h–1), thus outperforming the currently-advanced PHE catalysts. The outstanding performance is due to the superiority of a direct 2D/2D Z-scheme core-shell fabrication, including a large surface area for light harvesting, facile charge separation and transfer, and the workability of Pt SAs sites. Theoretical investigations provide additional insight into the mechanistic process of the ternary system for PHE reactions.

Heteroatom doping into metal oxides advantageously modulates optoelectronic properties and provides promising possibilities for efficient light-to-energy conversion. Herein, nitrogen-doped ceria (N-CeO2) nanoparticles are prepared and then coupled with nitrogen-doped graphene (N-Gr) to create an active and long-lasting N-CeO2/N-Gr heterocatalyst. Optoelectronic features of N-doping materials (e.g., plasmon) are significantly improved toward the visible-light region, particularly for 3.9% N-CeO2/N-Gr nanocomposites. Namely, the 3.9% N-CeO2 possesses numerous catalytic active defects (N states, oxygen vacancy, and Ce3+ species), leading to a narrow bandgap energy and to the improved plasmonic properties of the ceria host, while the N-Gr preferably serves as an electron scavenger to collect plasmon-generated hot electrons migrating from 3.9% N-CeO2 to drive photocatalytic reactions under the irradiation of visible-light. Resultantly, the 3.9% N-CeO2/N-Gr photocatalyst delivers an impressive hydrogen evolution reaction (HER) rate of 3.7 μmol mgcat−1 h−1 under visible-light, which is 2.0- and 8.2-fold greater than those obtained from 3.9% N-CeO2 and CeO2 ones, respectively. Additionally, the combination of 3.9% N-CeO2 and N-Gr synergistically produces a long-lasting plasmonic HER photocatalyst system. Metal-free plasmonic N-doped oxides supported by N-doped graphene pave a promising pathway for efficient light-to-hydrogen fuel production accordingly.

We demonstrated lasing from TM modes in photonic nanobeam cavities. By varying the radius of air holes, Q-factor reaches around 1,000,000. The single-mode lasing action was performed at room temperature, and confirmed by numerical results.

Supported plasmonic Au nanoclusters (NCs) consisting of a few tens of atoms can potentially offer great advantages for the light-driven hydrogen evolution reaction (HER). Here, we report on the synthesis of well-dispersed and stable plasmonic Au NCs of 0.5-1.0 nm size on nitrogen-doped high surface area graphene (N-Gr) via freeze-drying and pyrolyzing in argon. The Au NCs/N-Gr photocatalyst exhibits under visible-light an impressive HER achievement (3.16 mu mol mg(cat)(-1) h(-1)) compared to Au single atoms/N-Gr (2.06 mu mol mg(cat)(-1) h(-1)) and Au nanoparticles (20 nm size)/N-Gr (0.92 mu mol mg(cat)(-1) h(-1)), with a maximum apparent quantum yield of 14.30%. These performances are synergistically attributed to two effects: (a) the strong surface plasmon resonance stimulated by light absorption and transferred near the surface of Au NCs, where the N-Gr conductive support can prolong the plasmon-produced hot electrons and direct the light-to-hydrogen conversion; (b) a high catalytic efficiency of Au NCs/N-Gr nanocomposites.

Correction for ‘Plasmonic Au nanoclusters dispersed in nitrogen-doped graphene as a robust photocatalyst for light-to-hydrogen conversion’ by Dung Van Dao et al., J. Mater. Chem. A, 2021, DOI: 10.1039/D1TA05445G.

Background Although lower urinary tract symptoms (LUTS) show a higher prevalence with age, few studies have reported the trend of these examination tools including uroflowmetry, urodynamic study and cystoscopy. Methods We evaluated the trend of performance of uroflowmetry, urodynamic study and cystoscopy by using National Health Insurance Data from 2010 to 2015. Primary outcome findings included cumulative number of patients per year, cumulative age-standardized patient rate per year and per age group, and correlation between the number of patients per year and the percentage of population per year in each age group. Results The overall trend for frequency of uroflowmetry and cystoscopy showed an increasing pattern (P < 0.001, respectively) while the trend for frequency of urodynamic study showed a decreasing pattern (P < 0.001). After age standardization, the overall trend showed similar results. Correlation between the number of patients per year and the percentage of population per year showed a positive correlation in the 50s age group and the above 70s age group (P = 0.003 and < 0.01, respectively) on uroflowmetry and in the above 70s age group (P < 0.01) on cystoscopy. Urodynamic study showed negative correlations in the 50s age group and the above 60s age group (P = 0.001 and 0.01, respectively). Conclusion National trend for frequency of uroflowmetry, urodynamic study and cystoscopy showed a different trend. The increasing trend of uroflowmetry and cystoscopy was related with growth of the aged population. However, urodynamic study showed a decreasing trend regardless of the age group., Graphical Abstract

In this study, Anchor Pile Precast Retaining Wall (APC) with screw shape flange was investigated and the results were arranged for designing APC specifications. Since precast materials require special care when they are manufactured, carried or treated, more accurate design and analysis of optimized dimension are needed : thus moment distribution of front foot was checked. Through full-scale field test, form and optimal stiffening shape were obtained and through fracture test with real load, applicable load was reasonably calculated. Research result in this thesis could be used as guideline or standard of designing and constructing Anchor Pile Precast Retaining Wall with screw shape flange.

A deep-sea pressure vessel needs to protect the internal electrical equipment from the high external pressure. Thus, the pressure vessel should be designed to be watertight and structurally safe. In this study, a cylindrical-type pressure vessel comprising a hollow cylinder and cover plates at both ends is investigated. For communication between the internal electronic equipment and the external device, holes are bored on the cover plate to install underwater connectors. Considering the type of internal equipment and underwater connector specifications, multiple holes may be required. These holes can affect the structural safety of the pressure vessel cover plate. In this study, the optimum design of the hole arrangement in consideration of the structural safety of the cover plate was performed.

Over the past years, many research works have been carried out to investigate the factors which govern the performance of diesel engine. The air pollutant emission from the diesel engine is still a significant environmental con cern in many countries. In the present study, new system of smoke reduction of diesel engi ne is proposed. This new system is using vacuum equipment for capture smoke. To confirm new system experiments were performed at engine dynamometer. As a result of this experiment, the smoke reduction of this system was identified. Key words: Smoke, Diesel Engine, Vaccum Generating †교신저자(국민대학교 자동차공학전문대학원, E-mail:siu-ki@hanmail.net, Tel: 02-943-7630)1 국민대학교 자동차공학전문대학원 1. 서 론 전 세계적으로 지구온난화에 따른 환경문제에 대응하기 위해 국제협약을 통한 이산화탄소 규제가 본격화되고 있는 시점에서 동일 배기량 기준 가솔린엔진보다 20-30% 정도 이산화탄소 배출량이 적은 디젤엔진은 차세대 친환경적인 운송역할의 가장 현실적인 대안으로 부각되고 있다[1,2]. 그러나 디젤엔진은 과잉공기 조건에서 연소가 진행되기 때문에 배기가스 중에 산소가 다량 존재하여 가솔린 엔진에 적용되는 3원 촉매를 사용할 수 없다. 또한 확산 연소 형태의 연소특성 때문에 질소산화물(NOx) 생성뿐만 아니라 부분적 과농 지역에서는 매연이 다량 생성되는 문제를 근본적으로 안고 있다[3-4]. 이러한 문제를 해결하기 위하여 고압분사 등과 같은 분사 전략의 향상과 유동에 의한 혼합의 조절 등으로 많은 배출가스의 저감이 이루어졌지만 현재 강화되는 배출가스 규제를 만족시키기 위해서는 후처리장치의 개발은 필수적이다. 그리고 최근 들어 미세입자의 유해성이 대두되면서 입자상물질(대부분 매연입자)에 대한 관심이 늘어나고 있다. 현재 입자상 물질의 저감기술로는 매연여과장치(DPF ; Diesel Particulate Filter) 가 가장 효과적이며, 정부에서는 일부지역에서의 차량에 장착을 의무화

The design theory and experimental results of a true random noise radar system are presented in this paper. Target range information can be extracted precisely by correlation processing between the delayed reference and the signal received from a target, and the velocity information by the Doppler processing with successive correlation data. A K-band noise radar system was designed using random FM noise signal, and the characteristics of the fabricated system were examined with laboratory and outdoor experiments. A C-band random FM noise signal was generated by applying a low-frequency white Gaussian noise source to VCO(Voltage Controlled Oscillator), and a K-band Tx noise signal with 100 ㎒ bandwidth was obtained by using a following frequency multiplier. Two modified waveguide horn arrays were designed and fabricated, and used for the Tx and Rx antennas. The required amount of Tx/Rx isolation was attained by using a coupling cancellation circuit as well as keeping them apart with predetermined spacing. A double down-conversion scheme was used in the Rx and reference channels, respectively, for easy post processing such as correlation and Doppler processing. The implemented noise radar performance was examined with a moving bicycle and a very high-speed target with a velocity of 150 ㎧. The results extracted by the Matlab simulation using the logging data were found to be in a reasonable agreement with the expected results.

A process for covalent attachment of amines to other amines is described for nanodevice preparation. This method utilizes a linker with aldehyde and N-hydroxysuccinimide ester terminals separated by a heptyl spacer. Nanodevices consisting of amine or hydrazide-containing molecules (Lucifer Yellow, fluorescein-5-thiosemicarbazide, and 2-hydrazinopyridine) attached to the surface of a generation 4 amine-terminated poly(amidoamine) dendrimer were prepared as model compounds. In spite of the numerous amine groups present on the dendrimer, aggregate formation was negligible, yielding well-defined nanoconstructs. This negligible aggregation was attributed to the reversible imine bonds formed between the surface amine groups of the dendrimer and the aldehyde group of the linker. We also prepared a dual fluorophore-dendritic nanodevice in which fluorescein was attached to the dendrimer surface via the linker while rhodamine was directly bound to the dendrimer surface. Fluorescence, UV-visible spectrophotometry, size exclusion chromatography, electrophoresis, and dynamic light scattering were used to analyze these nanodevices.

The design technology to be developed in this study is technology related to the metal panel corner processing method of very high value-added, interior and exterior cladding material, in the architecture. This study is aimed at designing a Bending Die System that enables metal panel corner processing for the first time in Korea, by improving corrosion resistance (durability), weather resistance and elegances (design) for the connecting part of right angle cornering, where most serious problems occur in using metal steel plates of 2.5mm or thicker. This is used as a kind of metal ball and as architectural interior and exterior cladding material.