Asymmetric acidic/alkaline N_(2)electrofixation accelerated by high-entropy metal-organic framework derivatives

High-entropy materials are composed of five or more metal elements with equimolar or near-equimolar concentrations within one crystal structure,which offer remarkable structural properties for many applications.Despite previously reported entropy-driven stabilization mechanisms,many high-entropy materials still tend to decompose to produce a variety of derivatives under operating conditions.In this study,we use transition-metal(Ni,Co,Ni,Zn,V)-based high-entropy metal-organic frameworks(HE-MOFs)as the precursors to produce different derivatives under acidic/alkaline treatment.We have shown that HE-MOFs and derivatives have shown favorable kinetics for N_(2)electrofixation in different pH electrolytes,specifically cathodic nitrogen reduction reaction in acidic media and anodic oxygen evolution reaction in alkaline media.To buffer the pH mismatch,we have further constructed an asymmetric acidic/alkaline device prototype by using bipolar membranes.As expected,the prototype showed remarkable activities,with an NH_(3)yield rate of 42.76μg h^(−1)mg^(−1),and Faradaic efficiency of 14.75%and energy efficiency of 2.59%,which are 14.4 and 4.4 times larger than those of its symmetric acidic and alkaline counterparts,respectively.

政府多部门决策协调的研究述评

目标和价值的多元化加剧了政府部门间的协调困境,从而导致一系列决策问题。政府科层结构衍生的协调机制和制度安排调节了部门间自主性与相互依赖性之间的张力,为它们达成决策共识创造出新的结构条件。然而,理解多部门决策协调的关键在于政府部门内生的政治动力和微观过程。在文献回顾的基础上发现,决策协调过程存在“兄弟”不平等现象,即部分政府部门可以利用信息、知识、职能配置和关系网络等资源来实现权威的“再生产”,进而获得更高决策影响力。非对称的权力和权威关系体现了政府部门间动态的行为结果。它涵盖了政府部门在不同决策情境如何通过“零”协调、说服、讨价还价和联盟建设等行为方式促成决策目标或手段的共识。有别于纯粹的竞争和合作定势,权威的“再生产”指向政府部门决策协调行为的一般性特征。

Magnetic Flux Leakage Course of Inner Defects and Its Detectable Depth

As a promising non-destructive testing(NDT)method,magnetic flux leakage(MFL)testing has been widely used for steel structure inspection.However,MFL testing still faces a great challenge to detect inner defects.Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked.In the paper,MFL course of inner defects is investigated by building magnetic circuit models,performing numerical simulations,and conducting MFL experiments.It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air.Further,a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects.Experimental results show that inner defects with buried depth up to 80.0 mm can be detected,suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.

MRBCH: A Multi-Path Routing Protocol Based on Credible Cluster Heads for Wireless Sensor Networks

Wireless sensor networks are widely used for its flexibility, but they also suffer from problems like limited capacity, large node number and vulnerability to security threats. In this paper, we propose a multi-path routing protocol based on the credible cluster heads. The protocol chooses nodes with more energy remained as cluster heads at the cluster head choosing phase, and then authenticates them by the neighbor cluster heads. Using trust mechanisms it creates the credit value, and based on the credit value the multi-path cluster head routing can finally be found. The credit value is created and exchanged among the cluster heads only. Theoretical analysis combined with simulation results demonstrate that this protocol can save the resource, prolong the lifetime, and ensure the security and performance of the network.

Effects of Pyridoxine on Selected Appetite Regulating Peptides mRNA Expression in Hypothalamic PVN/ARC Nuclei and Gastrointestinal Tract Tissues

An experiment was conducted to investigate the effect of dietary pyridoxine on the gene expression of appetite-regulating peptides in the hypothalamus and gastrointestinal tract of rabbits. Thirty-two rabbits were randomly divided into 2 treatments for 8 weeks (16 replicates/group and 1 rabbit/replicate). The treatments were fed a basal diet (control, measured pyridoxine content is 4.51 mg/kg) and the basal diet with a pyridoxine supplementation at 10 mg/kg (pyridoxine, measured pyridoxine content is 14.64 mg/kg). The results showed that dietary pyridoxine did not significantly alter the mRNA levels of neuropeptide Y, agouti related peptide, pro-opiomelanocortin and cocaine, amphetamine regulated transcript, peptide YY and cholecystokinin in arcuate nucleus, peptide YY in jejunum and ileum, and cholecystokinin in duodenum, jejunum and ileum (P > 0.05). Compared with the control, the mRNA levels of corticotropin-releasing hormone and melanocortin 4 receptor in paraventricular nuclei and peptide YY in duodenum were significantly decreased after pyridoxine treatment (P 0.05). In conclusion, the appetite genes of melanocortin 4 receptor and corticotropin-releasing hormone in paraventricular nuclei and peptide YY in duodenum are involved in the pyridoxine-caused hyperphagia.

Controlled on-chip fabrication of large-scale perovskite single crystal arrays for high-performance laser and photodetector integration

Metal halide perovskites possess intriguing optoelectronic properties,however,the lack of precise control of on-chip fabrication of the large-scale perovskite single crystal arrays restricts its application in integrated devices.Here,we report a space confinement and antisolvent-assisted crystallization method for the homogeneous perovskite single crystal arrays spanning 100 square centimeter areas.This method enables precise control over the crystal arrays,including different array shapes and resolutions with less than 10%-pixel position variation,tunable pixel dimensions from 2 to 8 pm as well as the in-plane rotation of each pixel.The crystal pixel could serve as a high-quality whispering gallery mode(WGM)microcavity with a quality factor of 2915 and a threshold of 4.14μJ cm^(-2).Through directly on-chip fabrication on the patterned electrodes,a vertical structured photodetector array is demonstrated with stable photoswitching behavior and the capability to image the input patterns,indicating the potential application in the integrated systems of this method.

化学气相沉积法制备钙钛矿-石墨烯薄膜及其柔性图像传感器

有机-无机杂化钙钛矿具有优异的光电性能,如大的光吸收系数、高载流子迁移率等,是理想的光电器件用光吸收材料.然而,杂化钙钛矿薄膜光电器件的性能受多方面因素的影响,例如致密程度、晶界等,同时其内部光激发电子-空穴对的复合也会降低器件的光电流和光响应度.本文以化学气相沉积法生长的高质量石墨烯薄膜为模板,通过两步化学气相沉积制备了甲胺铅碘/石墨烯异质结,并以此制备了柔性光探测器.首先,在生长体系中引入碘化铅,在石墨烯表面外延生长得到高质量的碘化铅;之后,引入甲基碘化铵,得到了具有大晶粒尺寸、致密的甲胺铅碘薄膜.进一步,以此复合薄膜为光吸收层,制备了柔性光探测器,其光响应度达到107 A/W.石墨烯的存在会抑制其中电子-空穴对的复合,从而提高器件的光电流.最后,在人类视觉系统的启发下,设计了柔性光电探测器阵列(24×24)图像传感器;其中,复合薄膜充当了视网膜中的视锥细胞.此图像传感器具有形状识别和颜色辨别的能力,在人造视网膜、生物医学成像、遥感和光通信高性能光电器件的构建方面具有应用潜力.