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81.
82.
Shanke Liu Hui Jin Yan Yang Lijun Yu 《International Journal of Hydrogen Energy》2021,46(54):27473-27482
Benzothiophene (BT) is a key sulfur-containing intermediate product in the thermal conversion process of coal and heavy oil. The migration process of the sulfur element may affect the thermal utilization design of BT. In this paper, BT was used as a model compound to simulate the supercritical water gasification (SCWG) process by molecular dynamics with a reactive force field (ReaxFF) method, and the laws of hydrogen production and sulfur migration mechanisms were obtained. Increasing the molecule number of supercritical water (SCW) and increasing the reaction temperature can enhance the generation of hydrogen and promote the conversion of organic sulfur to inorganic sulfur. Water was the main source of H2, and H2S was the main gaseous sulfur-containing product. SCW had a certain degree of oxidation due to a large number of hydroxyl radicals, which could increase the valence of sulfur. The conversion process of BT in SCW was mainly divided into four stages, including thiophene ring-opening; sulfur separation or carbon chain broke with sulfur retention; carbon chain cleaved, and gas generation. The lumped kinetic parameters of the conversion of sulfur in BT to inorganic sulfur were calculated, and the activation energy was 369.98 kJ/mol, which was much lower than those under pyrolysis conditions. This article aims to clarify the synergistic characteristics of hydrogen production and sulfur migration in the SCWG process of BT from the molecular perspective, which is expected to provide a theoretical basis for pollutant directional removal during hydrogen production by sulfur-containing organic matters in SCW. 相似文献
83.
84.
《International Journal of Hydrogen Energy》2021,46(79):38983-38991
Water electrolysis is a process that can produce hydrogen in a clean way when renewable energy sources are used. This allows managing large renewable surpluses and transferring this energy to other sectors, such as industry or transport. Among the electrolytic technologies to produce hydrogen, proton exchange membrane (PEM) electrolysis is a promising alternative. One of the main components of PEM electrolysis cells are the bipolar plates, which are machined with a series of flow distribution channels, largely responsible for their performance and durability. In this work, AISI 316L stainless steel bipolar plates have been built by additive manufacturing (AM), using laser powder bed fusion (PBF-L) technology. These bipolar plates were subjected to ex-situ corrosion tests and assembled in an electrolysis cell to evaluate the polarization curve. Furthermore, the obtained results were compared with bipolar plates manufactured by conventional machining processes (MEC). The obtained experimental results are very similar for both manufacturing methods. This demonstrates the viability of the PBF-L technology to produce metal bipolar plates for PEM electrolyzers and opens the possibilities to design new and more complex flow distribution channels and to test these designs in initial phases before scaling them to larger surfaces. 相似文献
85.
Tian Xie Haixia Zhao Zunhang Lv Guangwen Xie Yan He 《International Journal of Hydrogen Energy》2021,46(1):581-588
This work demonstrates a facile Nb2O5-decorated electrocatalyst to prepare cost-effective Ni–Fe–P–Nb2O5/NF and compared HER & OER performance in alkaline media. The prepared electrocatalyst presented an outstanding electrocatalytic performance towards hydrogen evolution reaction, which required a quite low overpotential of 39.05 mV at the current density of ?10 mA cm?2 in 1 M KOH electrolyte. Moreover, the Ni–Fe–P–Nb2O5/NF catalyst also has excellent oxygen evolution efficiency, which needs only 322 mV to reach the current density of 50 mA cm?2. Furthermore, its electrocatalytic performance towards overall water splitting worked as both cathode and anode achieved a quite low potential of 1.56 V (10 mA cm?2). 相似文献
86.
Hang Shi Qiuyang Yu Guoliang Liu Xiaohong Hu 《International Journal of Hydrogen Energy》2021,46(33):17097-17105
Transition metal phosphides (TMPs) have been considered as cheap alternatives of precious metal platinum for electrochemical hydrogen evolution reaction (HER). In the past decades, many reports have indicated that the engineering of heterointerfaces between different components could efficiently enhance the activity of HER catalysts. Here, we report a facile method to construct Ni12P5–Ni2P heterostructure by using a low temperature phosphorization strategy. The obtained Ni12P5–Ni2P heterostructure shows high activity toward HER with an overpotential value of 166 mV at 10 mA cm?2 and a Tafel slope of 60 mV dec?1 in 0.5 M H2SO4. Compared with pure Ni2P and Ni12P5, the Ni12P5–Ni2P heterostructure has more active sites and faster HER kinetics due to the presence of the interfaces between Ni12P5 and Ni2P. Furthermore, we used the obtained Ni12P5–Ni2P as cathodic catalyst and IrO2/Ti as anodic material to set up a proton exchange membrane (PEM) electrolyzer which shows good stability after 120 h continuous constant current electrolysis at 200 mA cm?2. This work demonstrates the positive effect of heterostructure for HER catalysts and provides a feasible strategy for constructing earth-abundant electrocatalysts. 相似文献
87.
目的 检测水产品及养殖水中丁香酚类化合物。方法 应用食品补充检验方法BJS 201908《水产品及水中丁香酚类化合物的测定》,以海水鱼、淡水鱼、海水虾、淡水虾及养殖水作为基质,测定6种丁香酚类化合物的含量。结果 通过对实际样品测定后发现,在水产品中检出了丁香酚类化合物,主要为丁香酚,检出率为28.9%,其中海水鱼相对突出。结论 本研究为丁香酚作为渔用麻醉剂提供了方法论,为丁香酚类化合物在水产运输的合理使用提供理论依据。 相似文献
88.
《Journal of dairy science》2021,104(11):11368-11385
The importance of drinking water for production and animal welfare is widely recognized, but surveys and animal welfare assessment schemes suggest that many dairy calves and dairy cows do not have sufficient access. Limit milk-fed calves drink more water than calves fed milk ad libitum, but ad libitum milk-fed calves also require access to drinking water, as milk does not meet the animal's requirement for water. At hot ambient temperatures and when calves are sick, access to water is especially important and should be provided at all times. Many young calves do not have access to water throughout 24 h, and whether healthy young calves require free access to water at all times, or from which age, is not clear and requires further study. Dairy cow free water intake (FWI) is largely determined by milk yield, and high-yielding dairy cows may drink up 100 L of water per day. Dry matter, crude protein, and salt content of feed, as well as ambient temperature, have considerable effects on dairy cow water intake. Deprivation of water affects meal patterning for the cow, as well as increased subsequent rate of drinking and compensatory water intake. Although dairy cow ad libitum water intake may exceed the water provision necessary to maintain production, offering water for ad libitum intake may be necessary to safe guard animal welfare. Cattle are suction drinkers that prefer to drink from large open water surfaces, and Holstein dairy cows can drink at a rate of up to 24 L/min. Research on the effect of design and placement of water troughs for indoor-housed dairy cows on their drinking behavior and water intake is limited. Access to a water source at pasture increases the time cows spend there, and access to shade reduces water requirements during periods of warm weather. In both indoor and pastured cattle, there is a lack of knowledge about the effect of stocking of water troughs on competition, drinking behavior, and intake in dairy cows. Studies on the effect of available water trough length and placement, and of the number of cows being able to drink from the same trough of a given dimension, are needed to evaluate current recommendations. 相似文献
89.
Effective distribution coefficients of 9 impurities in 1,2-diphenylethane have been calculated by directional crystallization under different ambient frozen temperature. The effect of varied zone size, temperature difference between the melt and ambient frozen environment, number of zone on purity of 1,2-diphenylethane have been also investigated during the process of zone refining. The results indicate that the product purity in the intermediate purified region with varied zone size is higher 0.04%-0.2% than that with constant zone size. The product purity increases with temperature difference between the melt and ambient frozen environment. The appropriate temperature difference is adopted 50℃. The product purity in the intermediate region of sample bar with 2 molten zones is higher 0.05%-0.43% than that with 1 molten zone. In addition, the change of enthalpy and entropy between impurities and 1,2-diphenylethane have been determined. 相似文献
90.
《Ceramics International》2022,48(8):10480-10485
Advanced nano-porous super thermal insulation materials are widely used in spacecraft, soler-thermal shielding, heat exchangers, photocatalytic carriers due to their low thermal conductivity. In this work, adopting dry preparation technology, nano-Al2O3, nano-SiO2, SiC and glass fibers as raw materials, novel nanometer alumina-silica insulation board (NAIB) were prepared. The preparation process was simple, safe, and reliable. In addition, the NAIB exhibited a high porosity (91.3–92.3%), small pore size (39.83–44.15 nm), low bulk density (0.22–0.26 g/cm3), better volumetric stability, and low thermal conductivity (0.031–0.050 W/(m·K) (200–800 °C)), respectively. The as-prepared NAIB could render them suitable for application as high-temperature thermal insulation materials. 相似文献