Current Understandings on Magnesium Deficiency and Future Outlooks for Sustainable Agriculture

The productivity of agricultural produce is fairly dependent on the availability of nutrients and efficient use. Magnesium (Mg²⁺) is an essential macronutrient of living cells and is the second most prevalent free divalent cation in plants. Mg²⁺ plays a role in several physiological processes that support plant growth and development. However, it has been largely forgotten in fertilization management strategies to increase crop production, which leads to severe reductions in plant growth and yield. In this review, we discuss how the Mg²⁺ shortage induces several responses in plants at different levels: morphological, physiological, biochemical and molecular. Additionally, the Mg²⁺ uptake and transport mechanisms in different cellular organelles and the role of Mg²⁺ transporters in regulating Mg²⁺ homeostasis are also discussed. Overall, in this review, we critically summarize the available information about the responses of Mg deficiency on plant growth and development, which would facilitate plant scientists to create Mg²⁺-deficiency-resilient crops through agronomic and genetic biofortification.     

Energy and economic analysis of a hydrogen and ammonia co-generation system based on double chemical looping

In this work, a model of hydrogen production by double chemical looping is introduced. The efficiency benefit obtained was investigated. The chemical looping hydrogen generation unit is connected in series to the downstream of a chemical looping gasification unit as an additional system for 100 MW·h coal gasification, with the function of supplementary combustion to produce hydrogen. Using Aspen Plus software for process simulation, the production of H_2 and N_2 in the series system is higher than that in the independent Chemical looping gasification and Chemical looping hydrogen generation systems, and the production of hydrogen is approximately 25.63% and 12.90% higher, respectively; The study found that when the gasification temperature is 900 °C, steam-carbon ratio is 0.84 and oxygen-carbon ratio is 1.5,the hydrogen production rate of the system was the maximum. At the same time, through heat exchange between logistics, high-pressure steam at 8.010×10~4 kg·h~(-1) and medium-pressure steam at 1.101×10~4 kg·h~(-1) are generated, and utility consumption is reduced by 61.58%, with utility costs decreasing by 48.69%. An economic estimation study found that the production cost of ammonia is 108.66 USD·(t NH_3)~(-1). Finally, cost of equipment is the main factors influencing ammonia production cost were proposed by sensitivity analysis.     

覆膜滤料用聚四氟乙烯微孔膜的制备及其性能研究

针对市场上常用4种SSG范围的聚四氟乙烯(polytetrafluoroethylene,简称PTFE)树脂原料,采用双向拉伸法制备PTFE微孔膜,分析微孔膜性能的差异,并确定最适用于覆膜滤料用PTFE树脂原料.分析了不同分子量PTFE树脂原料的相对标准密度(SSG)、粒径、挤出压力和含水率等参数,采用不同分子量树脂原料来制备PTFE微孔膜,并表征PTFE微孔膜力学、厚度、结晶度、孔径、孔隙率和透气性能.研究表明:SSG的大小会影响PTFE微孔膜的力学性能(最大力、断裂伸长率)和孔结构(孔径、孔隙率),随SSG的增大呈现先上升后下降的趋势,在2.170～2.189范围内达到最优;结晶度与SSG的大小成正相关,而微孔膜透气性能主要与其孔结构有关,与孔径和孔隙率的变化趋势具有一致性.得出结论:PTFE树脂原料SSG分布在2.170～2.189范围时,制备的PTFE微孔膜最适用于覆膜滤料领域.     

基于区块链技术的智能电网数据管理框架研究

为解决智能电网在数据管理过程中的数据安全性没有保障且准确率较低的问题,提出基于区块链技术的智能电网数据管理框架.以智能电网数据管理系统为研究对象,以区块链技术为核心,通过区块链与智能电网数据管理的融合分析与安全性分析2方面讨论区块链技术在智能电网数据管理中的应用可行性.分别研究数据采集层、场景应用层等2个层级的核心功能,形成一个能够保障数据安全与准确率的智能电网数据管理框架,一次性解决智能电网数据管理的信息存储、安全管理、精密度提高等问题.     

综合能源互联网配电网故障定位与隔离的研究

基于"互联网+"的智慧能源互联网综合服务是互联网在电力行业的体现,充分利用了计算机技术、信息技术及人工智能技术等,具有信息的高效处理与状态的全面感知等优点,是实现万物互联互通的重要手段.现阶段配电网故障定位与隔离存在过程较繁琐、计算量及存储量大等缺陷,因此结合互联网中边缘计算的思想,提出一种基于综合能源互联网的配电网故障定位与隔离方法,设计了适用于综合能源互联网中配电网故障定位与隔离的模式与算法,实现了高效、快速定位的目标,同时减少了计算量与存储量,最后通过算例验证了方法的有效性.     

基于PI与 QPR双闭环控制的光伏并网系统控制策略∗

传统的比例积分(PI)控制器在光伏三相逆变器系统中存在无法实现无静差跟踪及谐振抑制效果较差的问题,为提高光伏三相逆变器系统谐振抑制效果及电流控制效果,提出一种基于PI与准比例谐振(QPR)双闭环控制的光伏三相逆变器系统控制策略.设计了基于PI与QPR双闭环控制的控制策略及控制框图,实现入网电流无静差跟踪,具有更好的入网电流波形及谐振抑制效果,提升了系统的稳定性.最后,通过在MATLAB/Simulink平台搭建仿真模型,验证了该控制策略的正确性和有效性.     

Influences of mullite fibers on mechanical and thermal properties of silica-based ceramic cores

Mullite fibers composite silica-based ceramic cores were successfully prepared by injection molding. The effects of mullite fibers on the mechanical and thermal properties of ceramic cores were investigated. The results indicated that the linear shrinkage was significantly decreased and the porosity was gradually increased with the increase of mullite fibers. In addition, the flexural strength for the room temperature and the simulated casting temperature of 1500°C was increased to a maximum value when the content of mullite fibers was about 1 wt.%, and then decreased with the increase of mullite fibers. The mullite fibers of 1 wt.% presented excellent mechanical properties with a linear shrinkage of .65%, a porosity of 6.96%, and a flexural strength of 17 MPa at room temperature and 34.83 MPa at the simulated casting temperature of 1500°C. Besides, the change in microstructure and properties in various contents of mullite fibers were analyzed.     

纳米MOFs及其衍生物在超级电容器中的研究进展

金属有机框架（MOFs）材料因其大的比表面积、可调控的孔道结构和丰富的活性位点引起了国内外学者们的广泛关注。近年来MOFs基材料广泛应用于能量储存与转化领域,但大多数MOFs基材料的低稳定性和低导电性等缺陷限制了其实际应用。通过对MOFs基材料进行改性,如采用共轭度高的有机配体以增加MOFs材料的稳定性,或MOFs衍生物以提高其氧化还原活性位点和导电性,从而达到提高MOFs基电极材料的电化学性能。主要介绍了原始MOFs及其衍生材料如碳材料、金属氧化物、金属硫化物、金属氢氧化物和金属磷化物等在超级电容器电极材料中的最新研究进展。研究表明,多金属MOFs材料或多金属MOFs衍生物有利于提高电极材料的电化学性能,而导电MOFs材料或MOFs衍生物中的碳材料有利于提高电极材料的导电性。最后对MOFs基电极材料在电化学储能领域中的研究做出了展望,指出MOFs基材料的形貌、组分和导电性是未来研究的发展方向。     

LaMgAl11O19-La2Ce2O7 复合陶瓷的高温相稳定性

La2Ce2O7(LC) 和 LaMgAl11O19(LMA) 是两种新型热障涂层材料。 LC 具有优良的热物理及抗腐蚀性能, 但 其断裂韧性差。 LMA 具有良好的综合性能, 特别是力学性能优良。 基于复合材料设计理念, 为充分利用 LC 和 LMA 的优势, 本文探究了制备 LMA-LC 双相复合陶瓷的可行性。 采用高温固相法合成了 LMA 和 LC 粉末, 重 点研究了 LMA 和 LC 的高温稳定性, 初步研究了 LMA-LC 复合陶瓷块材的力学性能。 结果表明： LMA 和 LC 在 高温下发生了化学反应, 反应程度随温度升高而加剧, 主要反应产物为 LaAlO3, 其在低温下的铁弹性可能是复 合陶瓷在室温下具有良好力学性能的原因。     

不同制备工艺对ZnS光学性能的影响

分别用真空热压、H2S模式的化学气相沉积以及S模式的化学气相沉积3种工艺方法制备了红外透过性能良好的ZnS材料.比较了不同的工艺过程对ZnS显微结构的影响,并且分析了不同制备方法形成的缺陷对光学性能的影响.探讨了热等静压工艺改善光学性能的原因和机理.透过谱图的测试表明,S模式的化学气相沉积法制备的ZnS具有最高的可见光至远红外的透过率.对3种方法制备的ZnS分别进行了热等静压后处理,发现对材料的光学透过性能都有不同程度的提高.