Yi Tian  Francisco Pelayo García de Arquer  Cao‐Thang Dinh  Gael Favraud  Marcella Bonifazi  Jun Li  Min Liu  Xixiang Zhang  Xueli Zheng  Md. Golam Kibria  Sjoerd Hoogland  David Sinton  Edward H. Sargent  Andrea Fratalocchi 《Advanced materials (Deerfield Beach, Fla.)》2017,29(27)

The direct conversion of solar energy into fuels or feedstock is an attractive approach to address increasing demand of renewable energy sources. Photocatalytic systems relying on the direct photoexcitation of metals have been explored to this end, a strategy that exploits the decay of plasmonic resonances into hot carriers. An efficient hot carrier generation and collection requires, ideally, their generation to be enclosed within few tens of nanometers at the metal interface, but it is challenging to achieve this across the broadband solar spectrum. Here the authors demonstrate a new photocatalyst for hydrogen evolution based on metal epsilon‐near‐zero metamaterials. The authors have designed these to achieve broadband strong light confinement at the metal interface across the entire solar spectrum. Using electron energy loss spectroscopy, the authors prove that hot carriers are generated in a broadband fashion within 10 nm in this system. The resulting photocatalyst achieves a hydrogen production rate of 9.5 µmol h^?1 cm^?2 that exceeds, by a factor of 3.2, that of the best previously reported plasmonic‐based photocatalysts for the dissociation of H₂ with 50 h stable operation.  相似文献   

    

Jesper Malling Schmidt  Lotte Bach Larsen  Marianne Hammershøj 《Journal of food science》2017,82(9):2056-2061

The objective was to prepare sheared gels of potato protein concentrate and evaluate the effect of pH (3, ～4, ～7), ionic strength (15 or 200 mM) and protein drying conditions (spray or freeze drying) on the final appearance and rheological characteristics. Heat‐set gels 3 % (w/w) at a high ionic strength (200 mM) resulted in an inhomogeneous appearance with presence of clots, while low ionic strength (15 mM) gave homogenous structures. Gels prepared at pH 3 became transparent while preparation above pH 3.0 resulted in high turbidity. Heat treatment and cooling resulted in gelation for all samples except freeze dried powder at pH 3.0. Flow curves during shear from 0.1 to 100 s^?1 were fitted by the Herschel–Bulkley model indicating shear thinning behavior for all samples except the freeze dried sample at pH 3 which displayed a Newtonian behavior. Oscillatory measurements after shear indicated viscus behavior (phase angle above 45°) for the spray dried sample at pH 3, and gelled behavior (phase angle above 45°) for the remaining gelled samples. Structure recovery was observed after shear in all samples except at pH 3.0. The data shows potato protein can be used as ingredient in protein beverages.  相似文献   

    

Cong Viet Phan  Hervé Di Benedetto  Cédric Sauzéat  Josselin Dayde  Simon Pouget 《Fatigue & Fracture of Engineering Materials & Structures》2017,40(12):2169-2182

Quantification of different effects (nonlinearity, heating, thixotropy, and fatigue) occurring during fatigue tests on bituminous mixtures is presented in this paper. A focus is given on the nonlinearity phenomenon. Continuous fatigue tests and a test with specific protocol (called fatigue tests to estimate biasing effects) were performed in tension/compression mode on cylindrical samples of the same material. The analysis of results reveals that reversible effects (nonlinearity, heating, and thixotropy) are important (more than 90% decrease at 100,000 cycles for a strain amplitude of 100 μm/m at 10 Hz) and cannot be ignored when interpreting classical fatigue tests. The nonlinearity effects respect the time‐temperature superposition principle, and they are more pronounced at “high” temperature (at the same frequency). Direction of nonlinearity curve in the Cole‐Cole axes is shown to be independent of temperature and frequency for the considered range.  相似文献   

    

Graeme Moad  Tu Le  San H Thang 《Polymer International》2017,66(11):1423-1423

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Tran Ngoc Nguyen;Phan Thanh Nam;Hieu Trinh; 《国际强度与非线性控制杂志
》2024,34(14):9402-9420

We present a new method to the problem of finding α$$ alpha $$-exponential state estimates for a class of 2-D positive discrete-time systems with bounded time-delays. A less conservative sufficient condition for the α$$ alpha $$-exponential stability is derived and tighter α$$ alpha $$-exponential state estimates are provided. The effectiveness of the presented method is illustrated through two numerical examples.  相似文献   

    

Phan Huy Hoang  Anh Tuan Hoang  Nguyen Hoang Chung  Le Quang Dien  Xuan Phuong Nguyen  Xuan Duong Pham 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(3):312-319

In this study, new and efficient sorbent with density 0.2 g/cm³ was fabricated by incorporating rice straw into polyurethane matrix to get an open cell structure material with high oil uptake capacity. The influences of various important factors such as amount of adding rice straw, size of rice straw particles, and adsorption time on oil adsorption capacity of new sorbent material were investigated. The results showed that the oil absorption rate occurred fast in first 15–30 min, then slowed down and reached saturation level after about 2 h of treatment. Oil adsorption capacity of the new sorbent material was relatively high, up to 12.0 g/g. In comparison with pristine polyurethane or lignocellulosic materials, the new sorbents had higher oil adsorption capacity. Some characteristics of the as-obtained sorbent, such as surface shapes and porosity, were also studied by SEM analysis.  相似文献   

    

R.K. Neerukatti  S. Datta  A. Chattopadhyay  N. Iyyer  N. Phan 《Fatigue & Fracture of Engineering Materials & Structures》2018,41(2):387-399

Fatigue damage characteristics of aluminium alloy under complex biaxial loads such as in‐phase and out‐of‐phase loading conditions and different biaxiality ratios have been investigated. The effects of microscale phenomena on macroscale crack growth were studied to develop an in‐depth understanding of crack nucleation and growth. Material characterization was conducted to study the microstructure variability. Scanning electron microscopy was used to identify the second phase particles, and energy dispersive X‐ray spectroscopy was performed to analyse their phases and elements. Extensive quasi‐static and fatigue tests were conducted on Al7075‐T651 cruciform specimens over a wide range of load ratios and phases. Detailed fractography analysis was conducted to understand the crack growth behaviour observed during the fatigue tests. Significant differences in crack initiation and propagation behaviour were observed when a phase difference was applied. Primarily, crack retardation and splitting were observed because of the constantly varying mode mixity caused by phase difference. The crack growth behaviour and fatigue lives under out‐of‐phase loading were compared with those under in‐phase loading to understand the effect of mixed‐mode fracture.  相似文献   

    

Thi Van Linh Nguyen  Thi Yen Nhi Tran  Duc Tri Lam  Long Giang Bach  Duy Chinh Nguyen 《Food Science & Nutrition》2019,7(11):3513-3519

Blanching is a pretreatment method that is often applied in fruit and vegetable processing to inhibit enzyme activity and reduce loss of food quality. It was recently discovered that well‐controlled microwave volumetric heating could improve the blanching efficiency and retain nutritional and sensorial values of product. This study was conducted to investigate effects of microwave blanching conditions on the quality of green asparagus (Asparagus officinalis L.) butt segments, a rich source of fiber and antioxidants but are often discarded during processing. The experiments were designed by one‐factor‐at‐a‐time method with two varying factors including blanching time (2, 4, 6, and 8 min) and microwave power output (150, 300, 450, and 600 W). Quality of product was evaluated by sensory, retention of phenolics, and free‐radical scavenging activity retention. The results showed that longer blanching time or higher microwave power was associated with reduced quality of green asparagus butt segment. Besides, the appropriate parameters for microwave blanching of the green asparagus butt segment was found at 300 W for 4 min.  相似文献   

    

Thang Viet Pham  Jeong‐Gil Kim  Jae Young Jung  Jun Hee Kim  Hyunjin Cho  Tae Hoon Seo  Hunsu Lee  Nam Dong Kim  Myung Jong Kim 《Advanced functional materials》2019,29(48)

The lack of cost effective, industrial‐scale production methods hinders the widespread applications of graphene materials. In spite of its applicability in the mass production of graphene flakes, arc discharge has not received considerable attention because of its inability to control the synthesis and heteroatom doping. In this study, a facile approach is proposed for improving doping efficiency in N‐doped graphene synthesis through arc discharge by utilizing anodic carbon fillers. Compared to the N‐doped graphene (1–1.5% N) synthesized via the arc process according to previous literature, the resulting graphene flakes show a remarkably increased doping level (≈3.5% N) with noticeable graphitic N enrichment, which is rarely achieved by the conventional process, while simultaneously retaining high turbostratic crystallinity. The electrolyte ion storage of synthesized materials is examined in which synthesized N‐doped graphene material exhibits a remarkable area normalized capacitance of 63 µF cm^?2. The surprisingly high areal capacitance, which is superior to that of most carbon materials, is attributed to the synergistic effect of extrinsic pseudocapacitance, high crystallinity, and abundance of exposed graphene edges. These results highlight the great potentials of N‐doped graphene flakes produced by arc discharge in graphene‐based supercapacitors, along with well‐studied active exfoliated graphene and reduced graphene oxide.  相似文献   

    

Bach Quoc Khanh  Masahide Hojo 《IEEJ Transactions on Electrical and Electronic Engineering》2019,14(8):1172-1180

This article introduces a new method for optimizing the placement of a multiple of D‐Statcoms for voltage sag mitigation in distribution systems. The D‐Statcom's placement is optimally selected not only for improving system voltage sag caused by a single fault event but also for all possible fault events in the system of interest. Therefore, D‐Statcom's placement is optimized in a problem of optimization where the objective function is to minimize the system voltage sag index—SARFIx. D‐Statcom's effectiveness for voltage sag mitigation is modeled based on the method of Thevenin's superimposition for the problem of short‐circuit calculation in distribution systems. This article considers the case of using a multiple of D‐Statcoms with a proposed voltage compensating principle that can be practical for large‐size distribution systems. This article uses the IEEE 33‐buses distribution feeder as the test system for voltage sag simulation and influential parameters to the outcomes of the problem of optimization are considered and discussed. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献