Metal Single-Atom Cocatalyst on Carbon Nitride for the Photocatalytic Hydrogen Evolution Reaction: Effects of Metal Species

Single-atom (SA) catalysts exhibit high activity in various reactions because there are no inactive internal atoms. Accordingly, SA cocatalysts are also an active research fields regarding photocatalytic hydrogen (H₂) evolution which can be generated by abundant water and sunlight. Herein, it is investigated whether 10 transition metal elements can work as an SA on graphitic carbon nitride (g-C₃N₄; i.e., gCN), a promising visible-light-driven photocatalyst. A method is established to prepare SA-loaded gCN at high loadings (weight of ≈3 wt.% for Cu, Ni, Pd, Pt, Rh, and Ru) by modulating the photoreduction power. Regarding Au and Ag, SAs are formed with difficulty without aggregation because of the low binding energy between gCN and the SA. An evaluation of the photocatalytic H₂-evolution activity of the prepared metal SA-loaded gCN reveals that Pd, Pt, and Rh SA-loaded gCN exhibits relatively high H₂-evolution efficiency per SA. Transient absorption spectroscopy and electrochemical measurements reveal the following: i) Pd SA-loaded gCN exhibits a particularly suitable electronic structure for proton adsorption and ii) therefore they exhibit the highest H₂-evolution efficiency per SA than other metal SA-loaded gCN. Finally, the 8.6 times higher H₂-evolution rate per active site of Pd SA is achieved than that of Pd-nanoparticles cocatalyst.     

EVA改进聚醋酸乙烯乳液粘合剂性能的研究

本研究采用EVA乳液作为种子进行聚合制备改性聚醋酸乙烯乳液粘合剂。讨论了EVA乳液的用量对聚合物的耐寒性、表面张力的影响。同时,对聚合温度、搅拌速度、引发剂用量、聚合保温时间等进行了选择。改性后的白胶粘合剂具有多次循环的冻融稳定性,且对低表面能材料的粘接强度明显高于通用白胶     

Label-free electrochemical immunoassay for the detection of human chorionic gonadotropin hormone

Here we report on a new and rapid immunoassay for the label-free voltammetric detection of human chorionic gonadotropin hormone (hCG) in urine. Monitoring the changes in the current signals of antibodies (Abs) before and after the binding of the antigen (Ag) provides the basis for an immunoassay that is simple, rapid, and cost-effective. Since hCG is found at highly elevated levels in pregnant female urine with the range of 30,000-200,000 mIU/mL (approximately 30-200 nM) by 8-10 weeks into pregnancy, its label-free electrochemical detection was achieved by using our method. The coverage of the electrode surface with the Ab and the incubation time with the target Ag were optimized for the detection of hCG. The limit of detection of our method was calculated to be 15 pM (n = 3, approximately 15 mIU/mL) in synthetic hCG samples and 20 pM (n = 3, approximately 20 mIU/mL) in human urine. The electrochemical results for the detection of hCG in the urine samples were in agreement with the results obtained using a reference system, enzyme-linked immunosorbent assay. Further research about the intrinsic electroactivity of Abs and their target molecules would surely provide new and sensitive screening assays, as well as extensive data regarding their interaction mechanisms.     

Desulfurization Model Using Solid CaO in Molten Ni-Base Superalloys Containing Al

Metallurgical and Materials Transactions B - Details of the desulfurization for molten Ni-base superalloys containing Al using solid CaO have been investigated, and the formula that explains the...     

A numerical study of wave propagation and run-up in water channels

It is important to understand how water waves propagate through water channels in order to reduce inundation damages induced by surges and/or tsunami run-up. For this purpose, a two-dimensional numerical model is developed based on Nonlinear Shallow Water Equations. In order to appropriately describe the strongly nonlinear hydrodynamics, a high-order TVD scheme is implemented. Model capabilities are confirmed through comparison with existing analytical studies including the dam-break problems, run-up and back-wash on a sloping bathymetry. The model is then applied to the study on the inundation of bore propagating in a channel of parabolic cross-section from a side breach.

     

Alloy Composition Screening for Ni-Base Turbine Disc Superalloys Using the Creep Property of Single Crystal

This paper proposes a method for alloy composition screening using the creep property of a single crystal (SC) for designing new Ni-base powder metallurgy (P/M) turbine disc superalloys. A commercial Ni-base disc alloy, U720Li®, a Ni-Co-base disc alloy, TMW-4M3, and a Ni-base conventionally cast alloy, TM-47, were selected for investigation. Their SC and P/M samples were prepared such that their γ/γ′ structures were similar. Moreover, tensile creep tests were performed on SC samples, and compressive creep tests were performed on SC and P/M samples. The tensile creep test results of SC samples at 1073 K (800 °C) and 735 MPa indicate that 0.2 and 1 pct creep times, as well as rupture life, are long in the order of TM-47 SC, TMW-4M3 SC, and U720Li SC. These results simulate the intragranular creep resistances of the corresponding P/M alloys. Furthermore, there is no significant difference in 0.2 and 1 pct compressive creep times between the SC and P/M samples of each alloy. Additionally, the 0.2 and 1 pct creep times of tensile and compressive creep tests of every alloy had an identical order. Therefore, alloy composition screening using SC creep property enables the design of new disc alloys with excellent creep resistance.

     

Proteomic and Biochemical Analyses of the Mechanism of Tolerance in Mutant Soybean Responding to Flooding Stress

To investigate the mechanism of flooding tolerance of soybean, flooding-tolerant mutants derived from gamma-ray irradiated soybean were crossed with parent cultivar Enrei for removal of other factors besides the genes related to flooding tolerance in primary generated mutant soybean. Although the growth of the wild type was significantly suppressed by flooding compared with the non-flooding condition, that of the mutant lines was better than that of the wild type even if it was treated with flooding. A two-day-old mutant line was subjected to flooding for 2 days and proteins were analyzed using a gel-free/label-free proteomic technique. Oppositely changed proteins in abundance between the wild type and mutant line under flooding stress were associated in endoplasmic reticulum according to gene-ontology categorization. Immunoblot analysis confirmed that calnexin accumulation increased in both the wild type and mutant line; however, calreticulin accumulated in only the mutant line under flooding stress. Furthermore, although glycoproteins in the wild type decreased by flooding compared with the non-flooding condition, those in the mutant line increased even if it was under flooding stress. Alcohol dehydrogenase accumulated in the wild type and mutant line; however, this enzyme activity significantly increased and mildly increased in the wild type and mutant line, respectively, under flooding stress compared with the non-flooding condition. Cell death increased and decreased in the wild type and mutant line, respectively, by flooding stress. These results suggest that the regulation of cell death through the fermentation system and glycoprotein folding might be an important factor for the acquisition of flooding tolerance in mutant soybean.     

Microstructure Development of Mechanical-Deformation-Induced Sn Whiskers

The development of the microstructure of mechanical-deformation-induced Sn whiskers on electroplated films has been examined using a focused ion beam system (FIB). The 6-μm-thick matte Sn films were compressed by using a ZrO₂ ball indenter under ambient conditions. After compression, tin whiskers and small nodules were found adjacent to, and several grains further away from, the indents. The cross-sectional microstructures of the indents and whiskers indicate that the lateral boundaries of the newly created grains caused by recrystallization are the main routes for stress relaxation.     

Development of energy saving operation technology for punctuality and ride comfort by optimizing the point of target pattern recreation

At present, there is a growing demand for energy saving to prevent global warming. Thus, the railway industry is also focusing on energy saving methods. Power consumption of running trains has a large variation of approximately 20% caused by drivers’ operation. Therefore, improving the running profile can considerably reduce energy consumption. Numerous algorithms for generating energy saving running profiles have been researched and developed. To adapt energy saving operation to various environments, we developed a technology that maintains punctuality without reducing the energy efficiency when temporary differences occur in driving conditions. We propose a method that determines the re-creation command point to complete the re-creation at the switching point of the driving operation in the existing energy-saving target pattern, to achieve both punctuality and ride comfort. As a result of verifying the effect of the proposed method on the conventional method via a simulation, it was confirmed that the proposed method can prevent the increase in the number of operation changes when the driving conditions change, whereas the conventional method increases the number of operation changes.