As a martensitic stainless steel, AISI 431 steel is widely used as a key material in marine and steam turbine applications. In this research, a plate of AISI 431 stainless steel was first fabricated ...using laser melting deposition process, and the microstructure evolutions during the deposition process, the phase transformation under different heat treatment conditions and the influences of microstructures on tensile properties of the steel were investigated. The results show that the laser deposited AISI 431 steel had a fine well-aligned directional microstructure, which consists of dendritic ferrite phases, inter-dendritic ferrite phases and (Cr, Fe)23C6 carbides. Due to the low bonding force between ferrite and carbides, cracks can easily generate and propagate along the interface, resulting in unsatisfied mechanical properties. After solution treatments at temperatures from 1000 to 1100°C, the interlayer heat affected zones of the steel were eliminated, and the carbides gradually dissolved when the solution temperatures were raised. The amount of ferrite did not change until reaching 1100°C, and the steel had the optimal mechanical properties after heat treatment at 1050°C with a strength of 1283MPa.
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•H2O form earlier than N2 at low temperature and the opposite is true at high heat.•Intermolecular hydrogen transfer occurs during the initial phase of the reaction.•Clusters cause ...theeasy existence of N2, but the nitrogen oxides are the opposite.•The Ea of the initial decomposition reaction of LLM-105 we got is 167.9 kJ/mol.
As one of the important high energetic insensitive explosives, LLM-105 has attracted considerably attention. In this work, the thermal decomposition of LLM-105 was analyzed at 2000, 2250, 2500, 2750, 3000, 3250, and 3500 K. Reaction times were controlled to be 200 ps. The results showed that the main small molecule products in this reaction stage were H2O, N2, CO2, and H2. At low temperatures, water molecules form earlier than nitrogen ones, while the opposite is found at high temperatures. In the initial stage of the reaction, LLM-105 often undergoes a large amount of intermolecular H-transfer and dimerization, and this phenomenon is significantly reduced as the temperature rises. On the other hand, LLM-105 itself is very easy to polymerize to form clusters, and its cyclic structure is more likely to form a macromolecular cluster by diverse linkages (e.g. CNNC). As the reaction progresses, the atoms of H, O, and N gradually escape from the cluster structure, but most of the oxygen atoms stay stable. The activation energy of the initial decomposition reaction of LLM-105 is 167.9 kJ/mol, which is in a reasonable range.
Lithium nitrate (LiNO3) is the most studied additive and co-salt for the electrolyte of lithium-sulfur (Li–S) batteries, its known function is to suppress the redox shuttle of soluble lithium ...polysulfide (PS, Li2Sn), which reflects as an increase in the battery’s coulombic efficiency and cycling stability, as well as a reduced self-discharge rate. The current understanding on this function is that LiNO3 reacts with Li to form a robust surface layer that consequently protects the Li anode from reacting with the dissolved PS. However, little is known on the sulfur cathode except that LiNO3 reduces and adversely affects the battery’s performance when the battery is discharged to lower than 1.7 V. In this paper we report a new finding on the role of LiNO3 in enabling the stable cycling of the sulfur cathode. We show that LiNO3 is capable of catalyzing the conversion of high soluble PS to slightly soluble elemental sulfur near the end of charging process, and that the combination of a soluble nitrate in the electrolyte and an insoluble nitrate in the sulfur cathode leads to synergetic improvement. In addition, a possible mechanism is proposed for the catalysis of LiNO3 on the conversion of PS to elemental sulfur.
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•Role of LiNO3 in Li–S batteries is reinvestigated with focus on sulfur cathode.•Nitrate anion catalyzes the conversion of polysulfide to elemental sulfur.•A catalysis mechanism of nitrate anion on the Li2Sn to S8 conversion is proposed.•Combination of a soluble nitrate and an insoluble nitrate leads to synergetic improvement.
Highlights ► We examined the changes of central cholinergic circuits in post-stroke dementia mice. ► Icariin can improve the learning and memory damage in mice with post-stroke dementia. ► Icariin ...can restore the damage of histone acetylation in cholinergic circuits. ► Improved histone acetylation is likely due to the increase of CREB phosphorylation.
Sulfonyl group-containing compounds constitute an important class of therapeutical agents in medicinal chemistry presumably because of the tense chemical structure and functionality of the sulfonyl, ...which could not only form hydrogen bonding interactions with active site residues of biological targets but also, as incorporated into core ring structure, constrain the side chains and allowed their specific conformations that fit the active sites. This review focuses on sulfonamides and sulfones, which cover more than 40 series and are associated with at least 10 potential pharmaceutical targets in pathways of glucose metabolism and insulin signaling. A large number of such compounds have been reported as pharmaceuticals every year in the last decade. In particular, increasing studies suggest that sulfonamides and sulfones play a key role in the design of pharmaceutical agents with potential application for the treatment of diabetes and its complications. First, they are inhibitors of a variety of enzymes including 11β-hydroxysteroid dehydrogenase type 1, α- glucosidase, carnitine palmitoyltransferase and cytosolic phosphoenolpyruvate carboxykinase, and in turn involved in the regulation of the metabolism of glucose. In addition, they are active as activators of glucokinase and as antagonists of ghrelin receptors. These enzyme and receptors are tightly associated with the regulation of glucose metabolism and the improvement of insulin resistance. Secondly, sulfonamides and sulfones act in the insulin secretion. As agonists, they activate insulin receptor tyrosine kinase and thus increase insulin sensitivity. Moreover, they as inhibitors suppress protein tyrosine phosphatase 1B and dipeptidyl peptidase IV, and thus normalize the insulin signaling pathway. Finally, a number of sulfonamides and sulfones are inhibitors of aldose reductase, which have been linked to diabetic complications.
As for the measurement of diffusion coefficient in transparent liquids by digital holographic interferometry, there are many kinds depending on the mathematical model and experimental setup. The ...method of using the distance of the peaks in concentration difference profile to determine diffusion coefficient by Mach-Zehnder interferometric experimental setup, is easy to handle. In order to improve the accuracy and convenience of measurement in this method, we combine procedures of hologram analysis used by Mialdun et al (2011) and those by He et al (2009). By using polynomial to fit the continuous phase difference (interference phase) of object beam, it can be more convenient and accurate to determine the distance between the two peaks. Besides, the shift of initial time has been discussed as a separated topic at the first time and two functions for minimization have been given for determination of the initial time in this paper. With the development, diffusion coefficient of KCl in water at 0.33mol/L and 25 °C has been measured. The diffusion coefficient is 1.844 × 10(-9) m2/s with the uncertainty of ± 0.012 × 10(-9) m2/s. Our measurement has more similar result with other methods than holographic interferometry. The relative uncertainty of diffusion coefficient in our experiment is less than 1% and total uncertainty of temperature is within ± 0.04 K.
Quantum states induced by single-atomic impurities are at the frontier of physics and material science. While such states have been reported in high-temperature superconductors and dilute magnetic ...semiconductors, they are unexplored in topological magnets which can feature spin-orbit tunability. Here we use spin-polarized scanning tunneling microscopy/spectroscopy (STM/S) to study the engineered quantum impurity in a topological magnet Co
Sn
S
. We find that each substituted In impurity introduces a striking localized bound state. Our systematic magnetization-polarized probe reveals that this bound state is spin-down polarized, in lock with a negative orbital magnetization. Moreover, the magnetic bound states of neighboring impurities interact to form quantized orbitals, exhibiting an intriguing spin-orbit splitting, analogous to the splitting of the topological fermion line. Our work collectively demonstrates the strong spin-orbit effect of the single-atomic impurity at the quantum level, suggesting that a nonmagnetic impurity can introduce spin-orbit coupled magnetic resonance in topological magnets.
Currently, the endemic situation of schistosomiasis has dropped to the lowest level in China; however, there are still factors affecting the transmission of schistosomiasis. Flood disasters may pose ...a great impact on the transmission of schistosomiasis and even affect the progress of schistosomiasis control and the consolidation of schistosomiasis control achievements. In 2020, major flood disasters occur across China. This paper analyzes the current status of schistosomiasis and the impact of flood disasters on the transmission of schistosomiasis in China, and systematically describes the assessment of and response to schistosomiasis transmission risk before flood disasters, the prevention of
infections during flood disasters and the assessment of the endemic situation of schistosomiasis and surveillance of schistosomiasis after flood disasters. It is considered that schistosomiasis control is an important part of conventional schistosomiasis control activities and an important part of anti-flood and schisto
It is well known that generic solutions of the heat equation are not analytic in time in general. Here it is proven that ancient solutions with exponential growth are analytic in time in {\mathbf ...{M}} \times (-\infty , 0. Here \mathbf {M}=\mathbf {R^n} or is a manifold with Ricci curvature bounded from below. Consequently a necessary and sufficient condition is found on the solvability of the backward heat equation in the class of functions with exponential growth.
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