可见光下光催化分解水制氢的研究进展

利用太阳能驱动光催化反应制备氢气成为了目前的研究热点。综述了近年来在可见光下光催化分解水制氢的研究进展,着重介绍了固溶体光催化剂、非金属化合物型光催化剂、Z型光催化系统及新型助催化剂的最新研究成果,并展望了光催化制氢的发展。     

铁镍合金/聚乳酸复合材料的熔融沉积成形制备及其电磁吸收性能和力学性能

在制备铁镍合金(FeNi50)/聚乳酸(PLA)复合线材的基础上,利用熔融沉积成形(FDM)制备出FeNi50/PLA复合材料.采用SEM、振动样品磁强计、矢量网络分析仪和万能试验机研究了FeNi50对复合材料微观形貌、磁性、电磁性能和力学性能的影响,并讨论了其反射损耗.研究发现,复合材料的饱和磁化强度和电磁性能随着F...     

A Semiempirical Model for Post-Yield Stress Instability in the Stress–Strain Response of 3D Lattice Structures under Compressive Loads

Mechanical behavior of lattice structures is important for a range of engineering applications. Herein, a new semiempirical model is proposed that describes the entire range of stress–strain response of lattice structures, including the stress-instability region which is modeled as an oscillator. The model can be fit to individual stress–strain curves to extract elastic modulus, yield stress, collapse stress, post-yield collapse ratio, densification strain, and the energy absorbed per unit volume. The model is fit to 119 unique experimental stress–strain curves from 13 research papers in literature covering four different lattice designs, namely, octet truss, body-centered cubic with vertical members, body-centered cubic, and hexagonal. Manufacturing methods (additive and conventional) and materials (metals and polymers) were also included in the analysis. The fitted model yields several new insights into the compression behavior of previously tested lattice structures and can be applied to additional lattice designs. Among other results, analysis of variance (ANOVA) reveals that the octet truss lattice demonstrates the highest post-yield collapse ratio and the smallest normalized energy absorption per unit volume amongst the lattice structures investigated. The proposed model is a powerful tool for designers to quantitatively compare and select 3D lattice structures with the desired mechanical characteristics.     

Low-Temperature Resistant Stretchable Micro-Supercapacitor Based on 3D Printed Octet-Truss Design

Recently, stretchable micro-supercapacitors (MSCs) that can be easily integrated into electronic devices have attracted research and industrial attentions. In this work, three-dimensional (3D) stretchable MSCs with an octet-truss electrode (OTE) design have been demonstrated by a rapid digital light processing (DLP) process. The 3D-printed electrode structure is beneficial for electrode-electrolyte interface formation and consequently increases the number of ions adsorbed on the electrode surface. The designed MSCs can achieve a high capacitance as ≈74.76 mF cm⁻³ under 1 mA cm⁻³ at room temperature even under a high mechanical deformation, and can achieve 19.53 mF cm⁻³ under 0.1 mA cm⁻³ at a low temperature (−30 °C). Moreover, finite element analysis (FEA) reveals the OTE structure provides 8 times more contact area per unit volume at the electrode-electrolyte interface compared to the traditional interdigital electrode (IDE). This work combines structural design and 3D printing techniques, which provides new insights into highly stretchable MSCs for next-generation electronic devices.     

Understanding the Role of (W,Mo, Sb) Dopants in the Catalyst Evolution and Activity Enhancement of Co3O4 during Water Electrolysis via In Situ Spectroelectrochemical Techniques

Unlocking the potential of the hydrogen economy is dependent on achieving green hydrogen (H₂) production at competitive costs. Engineering highly active and durable catalysts for both oxygen and hydrogen evolution reactions (OER and HER) from earth-abundant elements is key to decreasing costs of electrolysis, a carbon-free route for H₂ production. Here, a scalable strategy to prepare doped cobalt oxide (Co₃O₄) electrocatalysts with ultralow loading, disclosing the role of tungsten (W), molybdenum (Mo), and antimony (Sb) dopants in enhancing OER/HER activity in alkaline conditions, is reported. In situ Raman and X-ray absorption spectroscopies, and electrochemical measurements demonstrate that the dopants do not alter the reaction mechanisms but increase the bulk conductivity and density of redox active sites. As a result, the W-doped Co₃O₄ electrode requires ≈390 and ≈560 mV overpotentials to reach ±10 and ±100 mA cm⁻² for OER and HER, respectively, over long-term electrolysis. Furthermore, optimal Mo-doping leads to the highest OER and HER activities of 8524 and 634 A g⁻¹ at overpotentials of 0.67 and 0.45 V, respectively. These novel insights provide directions for the effective engineering of Co₃O₄ as a low-cost material for green hydrogen electrocatalysis at large scales.     

不同环境因子对扩展青霉和指状青霉生长和产酸的影响

扩展青霉 (Penicillium expansum)和指状青霉(Penicillium digitatum)是两种典型采后致病菌,其中扩展青霉能够引起苹果、梨、猕猴桃、樱桃等水果的采后贮藏期腐烂,指状青霉则是引起柑橘类水果采后及贮藏期间腐烂的主要致病菌之一。为明确两株青霉菌生长及产酸的适宜环境条件,本试验对不同营养、温度、pH值、光照等条件下青霉菌的生长情况进行了研究。结果表明,在实验给定的条件下,最适宜扩展青霉生长和产酸的培养基为马铃薯葡萄糖琼脂培养基,温度分别为25℃和20℃,pH分别为4和10,均为黑暗环境;最适宜指状青霉生长和产酸的培养基为马铃薯葡萄糖琼脂培养基,温度均为20℃,pH分别为4和8,均为黑暗环境。这为后续对两株菌株产酸及致病性的探究提供科学依据。     

硼对烤烟生长及养分吸收的影响

在溶液培养条件下,研究了不同B033-浓度对烤烟生长和养分吸收的影响.结果表明,营养液中B033-浓度为0 50-2.00mg/L的各处理烤烟的株高和干物质的积累量高于其他3个处理.不同B033-浓度下烤烟各器官对钾的吸收最多,氮次之,磷最少.BO33-浓度为0 50-2.00mg/L的各处理,烤烟各器官对氮磷钾的吸收量明显高于其他处理.缺硼(BO33-＜0 50mg/L)或硼浓度过高(BO33≥200mg/L)时都会抑制烤烟的生长发育、干物质和养分的积累.     

紫外线消毒对水处理系统的微生物的杀菌效果研究

紫外线消毒是一种有效经济的消毒方法,其能在几秒钟内杀灭病原微生物,并不残留有害物质和不影响水的风味或口感。生产用水中的微生物指标非常重要,本论文通过研究在紫外线杀菌前后,水处理系统中的水所含的大肠杆菌和菌落总数的变化情况。     

颜色技术原理及在印染中的应用(七)第六篇同色异谱颜色及光源显色性的评价

在纺织印染等工业应用中,颜色的同色异谱问题十分普遍.该篇详细介绍了同色异谱颜色的概念及其评价方法;指出了照明光源对物体颜色的影响,取决于光源的显色性,给出了CIE推荐的光源显色性指数计算方法.     

翡翠中蜡质物和高分子聚合物充填处理尺度的判别

在翡翠的漂白、酸碱蚀、蜡质物和高分子聚合物注入等项实验研究的基础上,利用傅立叶变换红外光谱仪,重点对蜡质物和高分子聚合物充填处理翡翠的红外吸收光谱进行表征.结果表明,利用2 800～3 000 cm-1范围内由蜡质物和高分子聚合物(CH2和CH3官能团)致红外吸收谱带的相对吸收比(Ra)和其半峰宽面积(Sa),可以对翡翠的优化与处理尺度进行判定,即:1/4＜Ra≤2/4,Sa≤15(无需标识);2/4＜Ra≤3/4,15＜Sa≤30(为"优化");3/4＜Ra≤4/4,30＜Sa(为"处理").对翡翠的漂白、漂白充填处理和酸碱蚀充填处理的本质与属性予以了剖析.