Hierarchical micro/nanostructures of Au thorned roses, which exhibit efficient SERS activity, were synthesized for the first time by a facile interfacial reaction route without introducing any surfactant, seed or template.
Abstract Fe‐doped ZnO ceramic nanofibers (CNFs) as specific structural features and unique properties synthesized by using electrospun technology. X‐ray diffraction disclosed the wurtzite phase, and the microscopy analysis by SEM revealed the formation uniform nanofibers with 400 nm in diameter. The UV–visible diffuse reflectance spectroscopy (DRS) was used to investigation the optical properties of the pristine and the various percentages Fe doped ZnO photocrystalysts. The photo‐reduction activities of photocatalyst were evaluated using methylene blue (MB) as organic contaminant irradiated with simulate solar light from xenon lamp. The photocatalytic results that 1% Fe‐doped ZnO CNFs exhibits efficient visible and UV light activity and excellent photo‐stability. The kinetic constant of MB degradation over 1% Fe‐doped ZnO is about 2.2 times higher than that over pure ZnO. The experiment demonstrated that the photodegradation efficiency of Fe‐doped ZnO was significantly higher than that of undoped ZnO.
Developing an efficient catalyst for H2 generation from hydrolysis of ammonia borane (AB) in a controllable and sustainable way is a prerequisite to implementing H2 as an alternative energy vector. To meet this requirement, the present work designs and constructs a potential Ag@Pd core–shell catalyst, in which the plasmonic Ag nanocube core acts as a light absorber and the ultrathin Pd shell as the actively catalytic site. First, the core–shell structure of the prepared Ag@Pd samples is characterized and confirmed by an electron microscope and energy dispersive spectroscopy. Then their catalytic performances for AB hydrolysis are investigated and compared with Ag nanocubes under the light on/off condition and at different temperatures. The results show that the H2 generation rate on Ag@Pd is greatly enhanced, which is found to benefit from the reduced activation energy under light illumination. Further investigation of wavelength-dependent performance verifies the plasmon-driven nature of the Ag@Pd catalysts. The subsequent optical simulation using the finite element method indicates that the absorbed light energy is instead preferential to dissipate into the nonplasmonic but catalytic Pd site when the Pd shell coats on the plasmonic Ag nanocube. This leads to the concentration of energetic charge carriers in the outer Pd shell and thus the much higher catalytic efficiency of Ag@Pd core–shell catalyst than its single compartment for breaking down the N–B bond of AB to produce H2 gas.
Abstract In order to provide a theoretical premise for the purification of soy oligosaccharides from soybean whey, this paper examines the yeast PL08 fermentation process for purifying functional soybean oligosaccharides. Using the logistic model and the Luedeking-Piret model, the kinetics of PL08 cell growth, sucrose consumption, and ethanol production were determined by nonlinear data fitting. The linearity of the models was as high as 0.98, indicating the viability of this method. At 30h, the batch fermentation procedure revealed that the purity of functional oligosaccharides was 94.12%, while the ethanol concentration continued to rise to 3.0%vol. Based on the results of kinetic studies, a 10L exponential feeding culture was conducted, and the results indicated that the alcohol concentration can be controlled below 0.10%vol, the maximum biomass concentration was 50.01g/L, and the maximum purity of functional soybean oligosaccharide was 95.59% in 21h.
In cold regions with high daily temperature gradients (>20 °C), the durability of cement-stabilized macadam (CSM) base materials is poor and prone to cracking. To effectively reduce the cracking of semi-rigid base layers in cold regions with high daily temperature gradients and extend fatigue life, this study focused on cracking and fatigue characteristics of CSM with a 10% commercial early strength agent (ESA) added by the external mixing method under different curing conditions. The ESA was manufactured by Jiangsu Subote New Materials Co., Ltd. (Nanjing, China). The curing conditions were divided into variable temperature (0-20 °C) and standard temperature (20 °C). CSM curing was carried out through a programmable curing box. The research results indicated that the variable temperature curing conditions reduced the strength and fatigue resistance of CSM and accelerated the modulus attenuation rate of CSM. At the same time, the drying shrinkage of CSM was greater. The temperature shrinkage coefficient and strain of CSM under variable temperature conditions were smaller than those under standard temperature conditions. The effect of variable temperature conditions on the cracking and durability of CSM could not be ignored in cold regions. Compared to standard temperature curing conditions, the indirect tensile strength of CSM reduced by 31.04% under variable temperature conditions, the coefficient of variation increased by 2.97 times, and the discrete type significantly increased. Compared with CSM without ESA, the dry and temperature shrinkage strains of CSM with 10% ESA were reduced by 24.65% and 26.10%, respectively. At a stress level of 0.6, compared to standard temperature curing conditions, the fatigue life of CSM decreased by 97.19% under variable temperature conditions. Under variable temperature conditions, the fatigue life of CSM with 10% ESA increased by 196 times compared to 0% ESA. Adding ESA enhanced the anti-shrinkage cracking, strength, and durability of CSM under variable temperatures. ESA incorporation effectively compensated for the weakened characteristics of CSM under variable temperature conditions. The study proposed a practical approach for boosting the durability of CSM in cold environments.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)