2.25Cr-1Mo钢和FV520B钢的氢脆敏感性对比试验研究

通过电化学充氢和慢应变拉伸试验以及SEM断口形貌观察对2.25Cr-1Mo合金结构钢和FV520B马氏体沉淀硬化不锈钢的氢脆敏感性做出了评价。结果表明,在充氢环境中两种材料表现出了相似的抗氢脆性能,两种材质试样的断面收缩率与未充氢试样相比均呈现出相同的下降趋势;氢对缺口强度的影响也比较接近,2.25Cr-1Mo钢和FV520B钢充氢后的强度衰减率分别为9.2%和8.6%;SEM断口分析结果显示:两种材料充氢后的断口形貌均表现出了相似的韧窝状断裂特征,它们的破坏形式并没有因为充氢而发生改变。由此可见,两种材料的抗氢能力处于同一等级,具有成本优势的2.25Cr-1Mo合金结构钢可以和FV520B沉淀硬化不锈钢一样用于氢介质条件下运行的透平式压缩机中。

Plasma electrolytic liquefaction of sawdust

As a renewable carbon resource, biomass can be converted into polyols, aromatic hydrocarbons, alkanes, and other products by traditional catalytic liquefaction method, which has been widely used in production and life. The efficient development and utilization of biomass energy will play a very positive role in solving the problems of energy and ecological environment. A way of combining the plasma electrolysis with traditional catalytic liquefaction realizes the efficient liquefaction of sawdust, which provides a new liquefaction way for traditional biomass conversion. In this experiment, the effects of solution composition, catalyst content and power supply on solution resistance and liquefaction rate are analyzed.It is found that solution composition and catalyst content have a great influence on solution resistance. The results show that the liquefaction rate is highest and the resistance is smallest when the solution resistance is 500 ?. The liquefaction rate is greatly affected by the solution temperature, and the solution temperature is determined by the output power between the two electrodes. The output power includes the heating power of the electric field and the discharge power of the plasma.We measure the electric potential field distribution in the solution and the plasma power. It is found that the output power between the two poles increases nonlinearly(from 0 to 270 W) with time. In two minutes, the electric field heating power increases from 0 to 105 W and then decreases to 70 W, while the plasma power increases from 0 to 200 W. It is well known that in the first 70 seconds of the experiment the electric field heating is dominant, and then the plasma heating turns into a main thermal source. In this paper, plasma electrolysis and traditional catalytic liquefaction are combined to achieve the efficient liquefaction of sawdust, which provides a new way for biomass liquefaction.

Increasing the·OH radical concentration synergistically with plasma electrolysis and ultrasound in aqueous DMSO solution

In recent years,significant increases in waste processing and material engineering have been seen by using advanced oxidation processes.The treatment results and energy yields of these processes are largely determined by the generation and retention of reactive oxygen species(ROS).However,increasing the amount of ROS remains a key challenge because of the unavailability of performance-and energy-efficient techniques.In this study,plasma electrolysis,ultrasound,and plasma electrolysis combined with ultrasound were used to treat dimethyl sulfoxide(DMSO)solutions,and the results showed that the two methods can synergistically convert filament discharge into spark discharge,and the conversion of the discharge mode can significantly increase the concentration of OH radicals and effectively improve the efficiency of DMSO degradation.We verified the rationality of the results by analyzing the mass transfer path of ROS based on the reaction coefficients and found that the OH radicals in aqueous solution were mainly derived from the decomposition of hydrogen peroxide.These findings indicated that the synergistic action of plasma electrolysis and ultrasound can enhance the production of chemically reactive species,and provide new insights and guiding principles for the future translation of this combined strategy into real-life applications.Our results demonstrated that the synergistic strategy of ultrasound and plasma electrolysis is feasible in the switching mode and increasing the ROS,and may open new routes for materials engineering and pollutant degradation.

Impact of microsecond-pulsed plasma-activated water on papaya seed germination and seedling growth

The seed of Carica papaya consists of a hard shell-like testa with inhibitors in vivo causing slow,erratic and asynchronous germination.In this work,plasma-activated water prepared by microsecond-pulsed plasma jets(μPAW)was applied to treat papaya seeds.TheμPAW after plasma activation of 30 min was about 40℃.The reactive species such as NO_(2),NO_(3),and H_(2)O_(2)in theμPAW activated from deionized water were measured and correlated to the seed germination rate and the seedling growth performance.TheμPAW-treated papaya seed achieved a higher germination rate of 90%,which is 26%higher than the control group using deionized water.Comparing the results with a hot water(40℃)reference group showed that the reactive species inμPAW played primary roles in germination improvement,with little effect caused by the heat shock.TheμPAW also sterilized the treated seeds,reducing the germination stress.The morphological change in the seeds was observed by SEM,showing an effect of physical etching after treatment promoting seed imbibition.The biochemical mechanism of the seed germination was deduced with reference to the evolution of surface chemistry,functional groups,and ABA content.The accelerated seed metabolism observed was corresponded to the chemical modification pathway.Besides,early seedlings developed from treated seeds were observed to be healthy,grow more leaves,and have better root structures.The content of MDA in the treated papaya seedlings decreased along with increased SOD and higher ion concentration.TheμPAW that can be prepared at atmospheric pressure for bulk production offers a low-risk and cost-effective seed priming technology that may significantly increase the production of agricultural crops.