Metal nanocrystals have been recognized as the main catalytic materials in many fields,but insufficient activity and stability,as well as high prices,have limited their large-scale potential *** one of the extremely p...
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Metal nanocrystals have been recognized as the main catalytic materials in many fields,but insufficient activity and stability,as well as high prices,have limited their large-scale potential *** one of the extremely promising alternatives toward metal in boosting their catalytic performance,nonmetallic atoms-doped metal nanocrystals have recently received extensive attention because of their high efficiency,chemical and structural durability,abundant reserve,and low *** this review,we highlight the most recent progress in this field and provide insights into their catalytic *** metalnonmetal nanocrystals prepared by doping metal nanocrystals with nonmetallic atoms are introduced and classified based on the types of nonmetallic atoms,including metal hydrides,borides,carbides,nitrides,oxides,phosphides,and ***,their applications in catalysis,especially in electrocatalysis and organic catalysis,have been summarized and ***,the conclusions and perspectives are given for the catalysis-driven rational design of metal-nonmetal nanocrystals in this minireview.
A fully elliptic numerical study has been carried out to investigate the three-dimensional turbulent developing flow in a helical square duct with large curvature. A two-layer zonal model is proposed and used, in whic...
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A fully elliptic numerical study has been carried out to investigate the three-dimensional turbulent developing flow in a helical square duct with large curvature. A two-layer zonal model is proposed and used, in which the whole region is divided into a viscosity-affected near wall layer and a fully turbulent region. A DSM closure is applied in the former, and a one-equation model is solved in the latter. The results presented in this paper cover a Reynolds number range of (l- 10) x 104. The development of flow is found to be dominated by radial pressure gradient and Dean-type secondary motion. The distribution of Reynolds stresses in fully developed flow exhibit a complex pattern of turbulence anisotropy The development of peripherally averaged friction factor and the distribution of local friction factor in fully developed flow are given and discussed.
Hilly terrain pipeline is a common form of pipeline in oil and gas storage and transportation industry. Due to the hilly terrain influence, the liquid at the elbow of the gathering pipeline is easy to flow back and ac...
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The effect of optical cleaning method combined with laser speckle imaging(LSI)was discussed to improve the detection depth of LSI due to high scattering characteristics of skin,which limit its clinical application.A d...
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The effect of optical cleaning method combined with laser speckle imaging(LSI)was discussed to improve the detection depth of LSI due to high scattering characteristics of skin,which limit its clinical application.A double-layer skin tissue model embedded with a single blood vessel was established,and the Monte Carlo method was used to simulate photon propagation under the action of light-permeating agent.808 nm semiconductor and 632.8 nm He–Ne lasers were selected to study the e®ect of optical clearing agents(OCAs)on photon deposition in *** show that the photon energy deposition density in the epidermis increases with the amount of tissue°uid replaced by *** with glucose solution,polyethylene glycol 400(PEG 400)and glycerol can considerably increase the average penetration depth of photons in the skin tissue,thereby raising the sampling depth of the *** the action of glycerol,PEG 400,and glucose,the average photon penetration depth is increased by 51.78%,51.06%,and 21.51%for 808nm,68.93%,67.94%,and 26.67%for 632.8 nm lasers,*** vivo experiment by dorsal skin chamber proves that glycerol can cause a substantial decrease in blood°ow rate,whereas PEG 400 can signicantly improve the capability of light penetration without a®ecting blood velocity,which exhibits considerable potential in the monitoring of blood°ow in skin tissues.
In this paper a projectile ion-recoil ion coincidence technique is used to investigate the transfer ionization processes in collisions of 0.22-6.30 MeV Cq+ ions and 0.25-6.35 MeV 0q+ ions (q=1, 2, 3, 4) with the H...
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In this paper a projectile ion-recoil ion coincidence technique is used to investigate the transfer ionization processes in collisions of 0.22-6.30 MeV Cq+ ions and 0.25-6.35 MeV 0q+ ions (q=1, 2, 3, 4) with the He atom separately. The cross section ratio f of transfer ionization to single electron transfer is measured, and the dependence of f on both charge state q and energy E of the projectiles is investigated. The electron-structure and the mechanisms leading to transfer ionization affect the dependence of f on q and E. Our measurements, along with other data published previously, suggest a similar dependence of f on charge state and energy of projectile for partially stripped ions over a large energy range. The maximum value of f is approximately 0.17q^0.60; the energy corresponding to maximum f is about 160q^0.60 keV/u.
SO_(2)and NO emitted from coal-fired power plants have caused serious air pollution in *** this study,a test system for NO oxidation using O_(3)is *** basic characteristics of NO oxidation and products forms are studi...
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SO_(2)and NO emitted from coal-fired power plants have caused serious air pollution in *** this study,a test system for NO oxidation using O_(3)is *** basic characteristics of NO oxidation and products forms are studied.A separate test system for the combined removal of SO_(2)and NO_(x)is also established,and the absorption characteristics of NO_(x)are *** characteristics of NO oxidation and NO_(x)absorption were verified in a 35 t·h^(-1)industrial boiler wet combined desulfurization and denitrification *** operating economy of ozone oxidation wet denitrification technology is *** results show that O_(3)has a high rate and strong selectivity for NO *** O_(3)is insufficient,the primary oxidation product is NO_(2).When O_(3)is present in excess,NO_(2)continues to get oxidized to N_(2)O_(5)or NO_(3).The removal efficiency of NO_(2)in alkaline absorption system is low(only about 15%).NOx removal efficiency can be improved by oxidizing NO_(x)to N_(2)O_(5)or NO_(3)by increasing ozone *** the molar ratio of O_(3)/NO is 1.77,the NOx removal efficiency reaches 90.3%,while the operating cost of removing NO_(x)per kilogram is 6.06 USD(NO_(2)).
For achieving high-speed requirement of underwater vehicle,a conceptual engine,which utilizes the hydroreactive characteristic of several metals under supercavitation environment,has been put forward. Especially,in or...
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For achieving high-speed requirement of underwater vehicle,a conceptual engine,which utilizes the hydroreactive characteristic of several metals under supercavitation environment,has been put forward. Especially,in order to obtain specific impulse as great as possible,a dual water injection system is taken into account. Then thermodynamic cycle model,which lead the improvement of power plant and energy system,is introduced in detail,and thermal efficiency is also analyzed. Furthermore,for investigating the performance of this kind of engine system,detailed thermodynamic calculation and analysis are achieved. Especially,regarding hydroreactive metal fuel Mg/AP/HTPB as our target fuel-rich propellant,considering its obvious deficient oxygen property and the energy property of magnesium/water reaction,theoretical calculation method is established by integrating chemical non-equilibrium with chemical equilibrium. Accordingly,low limit of primary water/fuel ratio is determined. In addition,the qualitative and quantitative relationship of performance parameters,such as theoretical specific impulse,nozzle exit temperature,characteristic velocity,etc.,versus water/fuel ratio is investigated respectively.
Solar-driven photocatalytic water/seawater splitting holds great potential for green hydrogen ***,the practical application is hindered by the relatively low conversion efficiency resulting from the inadequate utiliza...
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Solar-driven photocatalytic water/seawater splitting holds great potential for green hydrogen ***,the practical application is hindered by the relatively low conversion efficiency resulting from the inadequate utilization of solar spectrum with significant waste in the form of ***,current equipment struggles to maintain all-day operation subjected to the lack of light during ***,a novel hybrid system integrating photothermal catalytic(PTC)reactor,thermoelectric generator(TEG),and phase change materials(PCM)was proposed and designed(named as PTC-TEG-PCM)to address these challenges and enable simultaneous overall seawater splitting and 24-hour power *** PTC system effectively maintains in an optimal temperature range to maximize photothermal-assisted photocatalytic hydrogen *** TEG component recycles the low-grade waste heat for power generation,complementing the shortcoming of photocatalytic conversion and achieving cascade utilization of full-spectrum solar ***,exceptional thermal storage capability of PCM allow for the conversion of released heat into electricity during nighttime,contributing significantly to the overall power output and enabling PTC-TEG-PCM to operate for more than 12 h under the actual *** to traditional PTC system,the overall energy conversion efficiency of the PTC-TEG-PCM system can be increased by∼500%,while maintaining the solar-to-hydrogen *** advancement of this novel system demonstrated that recycling waste heat from the PTC system and utilizing heat absorption/release capability of PCM for thermoelectric application are effective strategies to improve solar energy *** flexible parameter designing,PTC-TEG-PCM can be applied in various scenarios,offering high efficiency,stability,and sustainability.
Supercritical water gasification is a promising technology for wet biomass *** this paper,Ni and other metal catalysts were synthesized by wet *** stability and catalytic activities of Ni catalysts were ***,catalytic ...
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Supercritical water gasification is a promising technology for wet biomass *** this paper,Ni and other metal catalysts were synthesized by wet *** stability and catalytic activities of Ni catalysts were ***,catalytic activities of Ni,Fe,Cu catalysts supported on MgO were tested using wheat straw as raw material in a batch reactor at 723 K and water density of 0.07 cm^(3)/*** results showed that the order of metal catalyst activity for hydrogen generation was Ni/MgO>Fe/MgO>Cu/***,the influence of different supports on Ni catalysts performance was *** results showed that the order of the Ni catalysts’activity with different supports was Ni/MgO>Ni/ZnO>Ni/Al_(2)O_(3)>Ni/ZrO_(2).Finally,the effects of Ni loading and the amount of Ni catalyst addition on hydrogen production,and the stability of Ni/MgO catalyst were *** was found that serious deactivation of Ni catalyst in the process of supercritical water gasification took *** if carbon deposited on the catalyst surface was removed by high temperature calcination and the catalyst was reduced with hydrogen,the activity of used catalyst was only partially restored.
This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the i...
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This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.
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