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1.
《International Journal of Hydrogen Energy》2022,47(6):3906-3917
The current trends in energy were described, the main of which is the use of alternative energy sources, especially hydrogen. The most common methods of hydrogen accumulation were proposed: accumulation of compressed gaseous hydrogen in high-pressure tanks; accumulation of liquid hydrogen in cryogenic tanks; storing hydrogen in a chemically bound state; accumulation of gaseous hydrogen in carriers with a high specific surface area. Based on the combination of advantages and disadvantages, the most promising methods of accumulation were selected: storage of liquid hydrogen and storage of hydrogen in carriers with a high specific surface area. The main requirement for materials for hydrogen storage by these methods was revealed – a high specific surface area. Prospects for the development of waste-free low-emission technologies due to the recycling of secondary raw materials and the development of low-temperature technologies for the synthesis of functional and structural materials were substantiated. The applicability of large-scale ash and slag waste from coal-fired thermal power plants as a raw material for obtaining materials by low-temperature technologies was shown. The traditional ways of using ash and slag waste as a raw material, active additive and filler in the production of cements were described. Modern technologies for the production of innovative materials with a unique set of properties were presented, namely carbon nanotubes, silica aerogel and geopolymer materials. The prospect of using geopolymer matrices as a precursor for the synthesis of a number of materials was described; the most promising type of materials was selected – geopolymer foams, which are mainly used as sorbents for purifying liquids and gases or accumulating target products, as well as heat-insulating materials. The possibility of obtaining products of any shape and size on the basis of geopolymer matrices without high-temperature processing was shown. The special efficiency of the development of the technology of porous granules and powders obtained from a geopolymer precursor using various methods was substantiated. The obtained granules can be used in the following hydrogen storage technologies: direct accumulation of hydrogen in porous granules; creation of insulating layers for liquid hydrogen storage units. 相似文献
2.
学习不仅仅是自然科学知识的学习,更是社会科学、民族文化、正确人生观和价值观的形成过程,“课程思政”无疑正是实现该目标的捷径,它是当前高等院校思想政治教育的新模式。如何提升学生解决“复杂工程问题”的能力成为高校开展工程教育和“新工科”的难点和重点,而课程思政正是培养学生解决“复杂工程问题”中所需要的非技术因素的重要途径。“自动控制系统工程设计”是自动化专业高年级学生的一门专业课,当前关于“课程思政”的论述是指导思想居多、实施经验以及案例设计较少,针对该问题以“自动控制系统工程设计”为例,详细给出了“课程思政”教学案例的具体实施过程,对同类课程提供参考。 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(36):16249-16261
Structure design is the primary strategy to acquire suitable ionomers for preparing proton exchange membranes (PEMs) with excellent performance. A series of comb-shaped sulfonated fluorinated poly(aryl ether sulfone) (SPFAES) membranes are prepared from sulfonated fluorinated poly(aryl ether sulfone) polymer (SPFAE) and sulfonated poly(aryl ether sulfone) oligomer (SPAES-Oligomer). Chemical structures of the comb-shaped membranes are verified by 1H nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra. The comb-shaped SPFAES membranes display more continuous hydrophilic domains for ion transfer, because the abundant cations and flexible side-chains structure possess higher mobility and hydrophilicity, which show significantly improved proton conductivity, physicochemical stability, mechanical property compared to the linear SPFAE membranes. In a H2/O2 single-cell test, the SPFAES-1.77 membrane achieves a higher power density of 699.3 mW/cm2 in comparison with Nafion® 112 (618.0 mW/cm2) at 80 °C and 100% relative humidity. This work offers a promising example for the synthesis of highly branched polymers with flexible comb-shaped side chains for high-performance PEMs. 相似文献
4.
《International Journal of Hydrogen Energy》2022,47(93):39338-39363
In the last few decades, global warming, environmental pollution, and an energy shortage of fossil fuel may cause a severe economic crisis and health threats. Storage, conversion, and application of regenerable and dispersive energy would be a promising solution to release this crisis. The development of porous carbon materials from regenerated biomass are competent methods to store energy with high performance and limited environmental damages. In this regard, bio-carbon with abundant surface functional groups and an easily tunable three-dimensional porous structure may be a potential candidate as a sustainable and green carbon material. Up to now, although some literature has screened the biomass source, reaction temperature, and activator dosage during thermochemical synthesis, a comprehensive evaluation and a detailed discussion of the relationship between raw materials, preparation methods, and the structural and chemical properties of carbon materials are still lacking. Hence, in this review, we first assess the recent advancements in carbonization and activation process of biomass with different compositions and the activity performance in various energy storage applications including supercapacitors, lithium-ion batteries, and hydrogen storage, highlighting the mechanisms and open questions in current energy society. After that, the connections between preparation methods and porous carbon properties including specific surface area, pore volume, and surface chemistry are reviewed in detail. Importantly, we discuss the relationship between the pore structure of prepared porous carbon with surface functional groups, and the energy storage performance in various energy storage fields for different biomass sources and thermal conversion methods. Finally, the conclusion and prospective are concluded to give an outlook for the development of biomass carbon materials, and energy storage applications technologies. This review demonstrates significant potentials for energy applications of biomass materials, and it is expected to inspire new discoveries to promote practical applications of biomass materials in more energy storage and conversion fields. 相似文献
5.
Sinan Zhang Yadonga Zhao Xueshuang Yao Zhenhong Zheng Chuyao Zheng Zhuo Jiang 《International Journal of Food Science & Technology》2022,57(7):4245-4253
Ripe carambolas are hard to store and transport, while freeze-dried ones are easy to store. However, its long production time leads to higher costs. This study shows that high hydrostatic pressure (HHP) treatment could shorten the freeze-drying time of carambola slices. After HHP treatment (25–250 MPa), the drying time of the fresh sample can be shortened by 33.3–44.4% and the distribution of water and pigment in tissues is much uniform. With the increment of the pressure, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging rate are increased. At 250 MPa, the total phenolic content (TPC) increased from 11.34 to 13.36 mg GAE g−1, and the total flavonoid content (TFC) of the control sample was increased from 10.77 to 12.73 mg RE g−1. Compared with the untreated sample, HHP treatment can enhance the flavour and shorten the freeze-drying time. This work guides the application of HHP technology for drying food processing. 相似文献
6.
Xin Li Yurui Wang Minxuan Xu Yueqin Shi Hemiao Wang Xin Yang Haoting Ying Qi Zhang 《应用聚合物科学杂志》2021,138(19):50406
Polymer electrets have revealed great potential application in electromechanical devices because of the low weight, large quasi-piezoelectric sensitivity, and excellent flexibility. For an electret, a permanent and macroscopic electric field exists on the surface, principally led by a macroscopic electrostatic charge on the surface or a net orientation of polar groups inside the object. Here, progress in the development of polymer electrets is reviewed. After a brief retrospect of the research courses and those typical polymer electrets that are classified into fluorine polymer and nonfluorine polymer, we present a survey on the charging methods, including corona, soft X-ray, contact, thermal and monoenergetic particle beams. The latest representative applications (i.e., power harvesting, sensors, field effect transistors, and biomedicine) based on polymer electrets are also summarized. Finally, we complete this review with a discussion on perspectives and challenges in this field. 相似文献
7.
死亡风险预测指根据病人临床体征监测数据来预测未来一段时间的死亡风险。对于ICU病患,通过死亡风险预测可以有针对性地对病人做出临床诊断,以及合理安排有限的医疗资源。基于临床使用的MEWS和Glasgow昏迷评分量表,针对ICU病人临床监测的17项生理参数,提出一种基于多通道的ICU脑血管疾病死亡风险预测模型。引入多通道概念应用于BiLSTM模型,用于突出每个生理参数对死亡风险预测的作用。采用Attention机制用于提高模型预测精度。实验数据来自MIMIC [Ⅲ]数据库,从中提取3?080位脑血管疾病患者的16?260条记录用于此次研究,除了六组超参数实验之外,将所提模型与LSTM、Multichannel-BiLSTM、逻辑回归(logistic regression)和支持向量机(support vector machine, SVM)四种模型进行了对比分析,准确率Accuracy、灵敏度Sensitive、特异性Specificity、AUC-ROC和AUC-PRC作为评价指标,实验结果表明,所提模型性能优于其他模型,AUC值达到94.3%。 相似文献
8.
《International Journal of Hydrogen Energy》2022,47(45):19758-19771
In this study, the effects of cell temperature and relative humidity on charge transport parameters are numerically analyzed. In order to perform this analysis, three-dimensional and anisotropic numerical models are developed. The numerical models are integrated into the experimental values for anisotropic electrical conductivities, as depending on cell temperature and relative humidity, that were obtained from our previous study. The achieved results indicate that the values of current densities in the in-plane direction increase with increasing cell temperature and relative humidity, while the current densities reach a maximum in the rib regions for both the numerical model at the through-plane direction. The behaviors of electrolyte potentials are similar with changes in the cell temperature and relative humidity. In addition, the cathode electrical potentials in both the in-plane direction and through-plane direction do not change to a considerable amount with increasing cell temperature and relative humidity. 相似文献
9.
以“创新、协调、绿色、开放、共享”为内核的新发展理念,是对马克思主义发展理念的继承和发扬,极具时代精神,富含问题意识,为高校思想政治教育发展、教育教学改革实践提供了强大的理论支撑。本文以“通信原理”为例,阐述了新发展理念在课程改革中的思路和方法,实现了思想政治教育与专业基础课程有机融合,为深化高校教学改革、创新人才培养模式提供了思路。 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(20):11007-11027
Cathode channel of a PEM fuel cell is the critical domain for the transport of water and heat. In this study, a mathematical model of water and heat transport in the cathode channel is established by considering two-phase flow of water and air as well as the phase change between water and vapor. The transport process of the species of air is governed by the convection-diffusion equation. The VOSET (coupled volume-of-fluid and level set method) method is used to track the interface between air and water, and the phase equilibrium method of water and vapor is employed to calculate the mass transfer rate on the two-phase interface. The present model is validated against the results in the literature, then applied to investigate the characteristics of two-phase flow and heat transfer in the cathode channel. The results indicate that in the inlet section, water droplets experience three evolution stages: the growing stage, the coalescence stage and the generation stage of dispersed water drops. However, in the middle and outlet sections of the channel, there are only two stages: the growth of water droplets, and the formation of a water film. The mass transfer rate of phase change in the inlet section of the channel varies over time, exhibiting an initial increase, a decrease followed, and a stabilization finally, with the maximum and stable values of 1.78 × 10?4 kg/s and 1.52 × 10?4 kg/s for Part 1, respectively. In the middle and outlet sections, the mass transfer rate increase firstly and then keeps stable gradually. Furthermore, regarding the distribution of the temperature and vapor mass fraction in the channel, near the upper surface of the channel, the temperature and vapor mass fraction first change slightly (x < 0.03 m) and then rapidly decrease with fluctuations (x > 0.03 m). In the middle of the channel, the temperature and vapor mass fraction slowly decrease with fluctuation. 相似文献