Graphitic carbon nitride (g-C3N4) is confronted with the issue of poor utilization of photogenerated charge carriers, thereby leading to limited performance of photocatalytic hydrogen (H2) production, which restricts ...
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Objective Port-wine stains (PWS) are congenital vascular malformations caused by the abnormal dilation of capillaries and venules in the skin. Affecting 0.3%‒0.5% of newborns, PWS typically manifest as pinkish patches...
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Objective Port-wine stains (PWS) are congenital vascular malformations caused by the abnormal dilation of capillaries and venules in the skin. Affecting 0.3%‒0.5% of newborns, PWS typically manifest as pinkish patches on the face and neck that darken and thicken over time, significantly impacting patients’physical and mental well-being. Pulsed dye laser (PDL) therapy, based on selective photothermolysis, is the gold standard for PWS treatment. By targeting hemoglobin in abnormal blood vessels with specific wavelengths, PDL induces thermal damage to the vasculature while sparing surrounding tissues. However, due to variability in skin types, lesion depths, and laser parameters, clinical outcomes often depend on subjective evaluations and physician experience. These limitations underscore the urgent need for objective, quantitative, and noninvasive methods to assess skin structure and monitor treatment efficacy. This study integrates reflectance spectroscopy with an inverse Monte Carlo radiation method to quantify changes in key skin parameters before and after laser treatment. By measuring and reconstructing parameters such as epidermal thickness, melanin volume fraction, blood volume fraction, and blood oxygen saturation, this study establishes a robust framework for evaluating treatment outcomes and optimizing laser parameters. Additionally, it investigates differences in treatment responses between pediatric and adult patients, providing critical insights for personalized therapeutic strategies. Methods Eleven patients with PWS underwent pulsed dye laser (PDL) therapy at a wavelength of 595 nm, with an energy density of 8 J/cm2 and a fixed spot diameter of 7 mm. Reflectance spectra of the skin were measured before and after treatment using an HR400 CG-UV-NIR spectrometer (Fig. 1). To enhance efficacy, a double-irradiation strategy was employed, in which the second laser exposure followed the first after five minutes. For spectral analysis, an inverse Monte Carlo r
Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst *** performance of the catalysts was tested to study the effect of suppor...
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Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst *** performance of the catalysts was tested to study the effect of support on Mn-based catalyst *** of the catalysts followed as Mn_(0.4)/Al>Mn_(0.2)/Al>Mn_(0.4)/Ti>Mn_(0.2)/Ti>MnO_(x)>Al_(2)O_(3)on the whole,indicating the synergism of MnO_(x)and Al_(2)O_(3)for NO catalytic *** were analyzed according to characterization *** oxygen on catalyst rather than lattice oxygen was detected as the active oxidizer for NO *** catalyst support,Al_(2)O_(3)provided more sites to carry surface adsorbed oxygen than TiO_(2),resulting in the presence of more active oxygen on Mn O_(x)/Al_(2)O_(3)than on MnO_(x)/TiO_(2).Moreover,MnO_(x)/Al_(2)O_(3)possessed high surface area and pore volume,which greatly benefited the adsorption of NO on catalyst and further favored the oxidation of NO by active *** these advantages helped Mn_(0.4)/Al exhibited the best catalytic efficiency.
The safe and efficient combustion of high-alkali coal under deep peaking conditions remains a critical research focus. Boiler operating parameters under such conditions frequently fluctuate, markedly though incomplete...
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The safe and efficient combustion of high-alkali coal under deep peaking conditions remains a critical research focus. Boiler operating parameters under such conditions frequently fluctuate, markedly though incompletely understood in their influence on fouling and slagging, necessitating further investigation. Here, mineral transformation and ash fusion characteristics during high-alkali coal combustion in the main combustion zone were simulated through thermodynamic equilibrium calculations, addressing its fouling issues under deep peaking conditions. Variable loads were decomposed into distinct factors for analysis due to challenges of direct simulation. Additionally, the plasma ashing method was employed to prepare ash samples. High-alkali coals with distinct properties exhibit significant variations in mineral distribution, elemental evolution, ash fusion temperature, and viscosity. Abundant fayalite (Fe2SiO4) was observed in Hongshaquan (HSQ) coal, forming stable mineral phases with other components. In Shaerhu (SEH) coal, sodium primarily exists in the gaseous phase at high temperatures, significantly contributing to fouling. Meanwhile, Jiangjunmiao (JJM) and Wucaiwan (WCW) coals demonstrate limited mineral phases but higher ash fusion temperatures, with over 30 % of iron in the gaseous phase. The mineral transformation and ash fusion behaviors in various local combustion atmospheres follow consistent trends. The formations of gaseous sodium hydroxide (NaOH(g)) and sodium oxide in the slag phase (Na2O(slag)) are promoted with weakening reducing atmospheres, while total gaseous sodium content decreases. The slag phases of calcium, magnesium, and iron increase, accompanied by a decline in ash viscosity. However, unburned carbon inversely influences mineral transformation and ash fusion characteristics compared to excess air coefficients. This research provides theoretical support for overcoming the key technical challenges associated with high-alkali coal combus
The methanation of CO 2 and supercritical CO 2 (scCO 2 ) fracturing represent effective approaches for CO 2 utilization and greenhouse effect mitigation. In these process, light gases like H 2 , O 2 , CO, CH 4 are com...
The methanation of CO 2 and supercritical CO 2 (scCO 2 ) fracturing represent effective approaches for CO 2 utilization and greenhouse effect mitigation. In these process, light gases like H 2 , O 2 , CO, CH 4 are commonly involved. However, limited studies have focused on the diffusion behavior of these gases in scCO 2 under high-pressure conditions, as well as a shortage of self-diffusion coefficient data and prediction equations specifically designed for scCO 2 solvents. To address this gap, molecular dynamics (MD) simulations were employed to compute the self-diffusion coefficients of several light gases in scCO 2 across a wide temperature range (313 K–713 K) and at high pressures (75.994 bar, 101.325 bar and 126.656 bar) under infinitely dilute conditions. The effects of temperature, density, viscosity, molecular mass, and solute–solvent interaction energy on the self-diffusion behavior were systematically analyzed. Two empirical equations (a Speedy–Angell-type power-law equation and a newly developed equation incorporating temperature, density, and viscosity) were refitted based on simulation data. The overall relative errors are 4.52% and 4.44%, respectively, indicating an improved accuracy compared to conventional experimental and MD-based empirical equations.
Large vertical pipes are key structures connecting subsea wells to offshore ***,existing studies mainly focus on small vertical *** a vertical acrylic pipe with 80 mm inner diameter and 11 m height,a high-speed camera...
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Large vertical pipes are key structures connecting subsea wells to offshore ***,existing studies mainly focus on small vertical *** a vertical acrylic pipe with 80 mm inner diameter and 11 m height,a high-speed camera was used to visually research the influences of pipe diameters,liquid properties and inlet effect on air-water co-flow *** flow regime maps of vertical pipes(diameters are in the range of 50e189 mm)were compared and the critical gas velocity of the transition boundary from bubble to slug flow tended to increase with the increase of diameters at D≥80 ***-flux models were established in different flow regimes and liquid properties have a significant effect on drift coefficients of bubble flow and slug flow(void fraction a≤0.4).The influence of inlet turbulent effect on the gas-liquid interface distribution gradually weakened and disappeared from the pipe base to 85D,where the flow was fully *** frequency has a trend of increase first and then decrease with the gas Weber numbers increasing at low liquid superficial velocities(J_(L)≤0.31 m/s).And on the basis of this law,a new slug frequency correlation was *** was found that there was an exponential relationship between the ratio of lengths of Taylor bubble to slug and the void fraction.
Bubbles formed during chemical processes in fluidized beds govern the bed hydrodynamics and opera-tional efficiency, thereby having a significant impact on their design and scale-up. In this study, a two-fluid model w...
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Bubbles formed during chemical processes in fluidized beds govern the bed hydrodynamics and opera-tional efficiency, thereby having a significant impact on their design and scale-up. In this study, a two-fluid model was used to simulate the bubble behavior in a quasi-two-dimensional fluidized bed within the bubble-based energy minimization multiscale (EMMS) approach. We performed experiments to verify the model and proposed a correlation of the heterogeneous index for various parameters to calculate the coefficient of drag for the bubble-based EMMS model. Moreover, the simulation results obtained from the homogeneous drag models and EMMS bubbling model were compared with experimental data and empirical correlations. The simulation results of the EMMS approach showed good agreement with the experimental data in the distribution of the vertical bubble velocity with chord length. Compared with the results from the homogeneous models, the distributions of vertical velocity and diameter of the bubbles predicted by the EMMS-bubbling model were in better agreement with empirical correlations. Moreover, the frequency distributions of bubble properties including bubble diameter, aspect ratio, and shape factor for different gas-inlet velocities were obtained.
A new concept of a supercritical water (SCW) circulating fiuidized bed reactor is proposed to produce hydrogen from coal/biomass gasification. The cyclone is a key component of the reactor system, in this paper, cyc...
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A new concept of a supercritical water (SCW) circulating fiuidized bed reactor is proposed to produce hydrogen from coal/biomass gasification. The cyclone is a key component of the reactor system, in this paper, cyclones with a single circular inlet (SCI) or a double circular inlet (DCI) were designed to adapt to the supercritical conditions. We evaluated the separation performance of the two cyclones using numerical simulations. A three-dimensional Reynolds stress model was used to simulate the turbulent flow of the fluid, and a stochastic Lagrangian model was used to simulate the particle motion. The flow fields of both cyclones were three-dimensionally unsteady and similar to those of traditional gas-solid cyclones. Secondary circulation phenomena were discovered and their influence on particle separation was estimated. Analyzing the distribution of the turbulence kinetic energy revealed that the most intensive turbulence existed in the zone near the vortex finder while the flow in the central part was relatively stable. The particle concentration distribution was non-uniform because of centrifugal forces. The distribution area can be divided into three parts according to the motion of the particles. In addition, the separation efficiency of both cyclones increased with the inlet SCaN velocity. Because of its perturbance flow, the DCI separator had higher separation efficiency than the SCI separator under comparable simulations. However, this was at the expense of a higher pressure drop across the cyclone.
In the pursuit of a global paradigm shift in energy structure and carbon neutrality objectives, high-temperature thermal energy storage technologies have garnered significant attention due to their high efficiency and...
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