Synthesis of Lightweight Renewable Microwave-Absorbing Bio-Polyurethane/Fe3O4 Composite Foam: Structure Analysis and Absorption Mechanism

Sustainable renewable polymer foam used as a lightweight porous skeleton for microwave absorption is a novel strategy that can effectively solve the problems of the large surface density, high additive amount, and narrow absorbing band of absorbing materials. In this article, novel renewable microwave-absorbing foams were prepared using Sapiumse biferum kernel oil-based polyurethane foam (BPUF) as porous matrix and Fe₃O₄-nanoparticles as magnetic absorbents. The microstructure and the microwave absorption performance, the structural effects on the properties, and electromagnetic mechanism of the magnetic BPUF (mBPUF) were systematically characterized and analyzed. The results show that the mBPUF displayed a porous hierarchical structure and was multi-interfacial, which provided a skeleton and matching layer for the Fe₃O₄ nanoparticles. The effective reflection loss (RL ≤ −10 dB) frequency of the mBPUF was from 4.16 GHz to 18 GHz with only 9 wt% content of Fe₃O₄ nanoparticles at a thickness of 1.5~5 mm. The surface density of the mBPUF coatings was less than 0.5 kg/cm² at a thickness of 1.8 mm. The lightweight characteristics and broadband absorption were attributed to the porous hierarchical structures and the dielectric combined with the magnetic loss effect. It indicates that the mBPUF is a prospective broadband-absorbing material in the field of lightweight stealth materials.     

Extraction,Characterization, and Platelet Inhibitory Effects of Two Polysaccharides from the Cs-4 Fungus

Cardiovascular diseases are associated with platelet hyperactivity, and downregulating platelet activation is one of the promising antithrombotic strategies. This study newly extracted two polysaccharides (purified exopolysaccharides, EPSp and purified intercellular exopolysaccharides, IPSp) from Cordyceps sinensis Cs-4 mycelial fermentation powder, and investigated the effects of the two polysaccharides and their gut bacterial metabolites on platelet functions and thrombus formation. EPSp and IPSp are majorly composed of galactose, mannose, glucose, and arabinose. Both EPSp and IPSp mainly contain 4-Galp and 4-Glcp glycosidic linkages. EPSp and IPSp significantly inhibited human platelet activation and aggregation with a dose-dependent manner, and attenuated thrombus formation in mice without increasing bleeding risk. Furthermore, the EPSp and IPSp after fecal fermentation showed enhanced platelet inhibitory effects. The results have demonstrated the potential value of Cs-4 polysaccharides as novel protective ingredients for cardiovascular diseases.     

CD73-Mediated Formation of Extracellular Adenosine Is Responsible for Adenosine A2A Receptor-Mediated Control of Fear Memory and Amygdala Plasticity

Adenosine A_2A receptors (A_2AR) control fear memory and the underlying processes of synaptic plasticity in the amygdala. In other brain regions, A_2AR activation is ensured by ATP-derived extracellular adenosine formed by ecto-5′-nucleotidase or CD73. We now tested whether CD73 is also responsible to provide for the activation of A_2AR in controlling fear memory and amygdala long-term potentiation (LTP). The bilateral intracerebroventricular injection of the CD73 inhibitor αβ-methylene ADP (AOPCP, 1 nmol/ventricle/day) phenocopied the effect of the A_2AR blockade by decreasing the expression of fear memory, an effect disappearing in CD73-knockout (KO) mice and in forebrain neuronal A_2AR-KO mice. In the presence of PPADS (20 μM) to eliminate any modification of ATP/ADP-mediated P2 receptor effects, both AOPCP (100 μM) and the A_2AR antagonist, {"type":"entrez-protein","attrs":{"text":"SCH58261","term_id":"1052882304","term_text":"SCH58261"}}SCH58261 (50 nM), decreased LTP magnitude in synapses of projection from the external capsula into the lateral amygdala, an effect eliminated in slices from both forebrain neuronal A_2AR-KO mice and CD73-KO mice. These data indicate a key role of CD73 in the process of A_2AR-mediated control of fear memory and underlying synaptic plasticity processes in the amygdala, paving the way to envisage CD73 as a new therapeutic target to interfere with abnormal fear-like emotional processing.     

简析利用衰减控制修正不规格网格多面函数在绘制降水等值线中的缺陷

本文采用不规则网格多面函数技术,通过增加衰减控制,很好地解决不规则网格多面函数等值线在处理降水等值线趋势一直延续的缺陷.算法一般步骤首先是根据散点划分网格,其次是散点插值到计算网格节点,再次是根据指定的等值线值,检索网格的各边节点.按确定的搜索算法连接等值线.     

高温碳酸盐岩油藏酸压用酸液体系发展与应用现状

塔河油田碳酸盐岩缝洞型油藏储层改造存在高温条件下酸岩反应速度快、滤失量大的特点,常规酸液体系难以实现深度改造和提高酸蚀裂缝导流能力的目的.通过多年室内研究与现场试验,形成了以胶凝酸、变黏酸、转向酸、地面交联酸为主的多套酸液体系.通过高温流变实验,分析不同油藏类型酸压适合的酸液体系,指导单井酸压酸液选型和工艺优化,取得较好的现场应用效果.     

Deep Learning Based User Grouping for FD-MIMO Systems Exploiting Statistical Channel State Information

The joint spatial division and multiplexing(JSDM) is a two-phase precoding scheme for massive multiple-input-multiple-output (MIMO) system under frequency divis...     

Improved sensing performance of WO3 nanoparticles decorated with Ag and Pt nanoparticles

Gas sensors built with metal oxide semicon-ductors have attracted tremendous attention due to the growing demand for the detection of inflammable,explo-sive and...     

天车调度在优化钢厂物流管制中的重要作用

运用物流学中装卸搬运的知识,归纳了现代制造流程中运输环节的功能和作用,分析了炼钢厂物流系统中天车作业的特点,并对钢厂时间因素和生产工艺进行了研究与分析,从中可知天车调度在优化钢厂物流管制中的重要作用。     

铈盐在铝合金阳极氧化后处理工序中的应用

将铝合金稀土转化膜成膜工艺用作阳极氧化后处理工艺.多种实验结果表明,阳极氧化后经稀土处理,膜的耐蚀性有明显的提高,铈盐对多孔氧化膜层具有封闭作用,其封闭效果可与常温封闭方法相比拟.