Synthesis of palladium-rare earth alloy as a high-performance bifunctional catalyst for direct ethanol fuel cells

Direct ethanol fuel cells (DEFCs) have drawn attention for their simplicity, rapid start-up, high power density and environmental friendliness. Despite these advantages, the widespread application of DEFCs faces challenges, primarily due to the inadequate performance of anode and cathode catalysts. Pd-based materials have shown exceptional catalytic activity for both the ethanol oxidation reaction (EOR) and the oxygen reduction reaction (ORR). Alloying noble metals with rare earth elements has emerged as an effective strategy to further enhance the catalytic activity by modulating the electronic structure. In this study, we synthesized a series of palladium-rare earth (Pd3RE) alloys supported on carbon to serve as bifunctional catalysts that efficiently promote both ORR and EOR. Compared to Pd/C, the Pd3Tb/C catalyst exhibits 3.1-fold and 1.8-fold enhancement in activity for ORR and EOR, respectively. The charge transfer in the Pd3Tb/C results in an electron-rich Pd component, thereby weakening the binding energy with oxygen species and facilitating the two reactions.

Recent advances in Ni-based catalysts for the electrochemical oxidation of ethanol

The electrochemical ethanol oxidation reaction(EOR) plays a crucial role in electrochemical hydrogen production and direct ethanol fuel cells, both vital for utilizing renewable energies. Ni-based catalysts are pivotal in enabling efficient EOR, leading to the formation of acetic acid/acetaldehyde or CO_(2). These can serve as alternative anodic oxidation reactions for oxygen evolution reaction(OER) in water electrolysis or the anodic reaction for direct ethanol fuel cells, respectively. This review explores recent advancements in EOR over Ni-based catalysts. It begins with an overview of EOR performance across various Ni-based catalysts, followed by an examination of the reaction chemistry, mechanism, and active sites.The review then delves into strategies for designing highly active Ni-based EOR catalysts. These strategies include promotion with transition metals, noble metals, nonmetals, and carbon materials, as well as creating amorphous structures, special morphologies, and single-atom catalysts. Additionally, it discusses the concept of self-supporting catalysts using three-dimensional porous substrates. Finally, the review highlights emerging methodologies that warrant further exploration, along with future directions for designing highly active and stable EOR catalysts.

Acetic acid-and furfural-based adaptive evolution of Saccharomyces cerevisiae strains for improving stress tolerance and lignocellulosic ethanol production

Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains.Development of industrial S.cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production.In this study,the acetic acid or furfural tolerance of different S.cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions.The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)furfural.Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production.The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.

The emerging role of mesenchymal stem cell-derived extracellular vesicles to ameliorate hippocampal NLRP3 inflammation induced by binge-like ethanol treatment in adolescence

Our previous studies have reported that activation of the NLRP3(NOD-,LRR-and pyrin domain-containing protein 3)-inflammasome complex in ethanol-treated astrocytes and chronic alcohol-fed mice could be associated with neuroinflammation and brain damage.Mesenchymal stem cell-derived extracellular vesicles(MSC-EVs)have been shown to restore the neuroinflammatory response,along with myelin and synaptic structural alterations in the prefrontal cortex,and alleviate cognitive and memory dysfunctions induced by binge-like ethanol treatment in adolescent mice.Considering the therapeutic role of the molecules contained in mesenchymal stem cell-derived extracellular vesicles,the present study analyzed whether the administration of mesenchymal stem cell-derived extracellular vesicles isolated from adipose tissue,which inhibited the activation of the NLRP3 inflammasome,was capable of reducing hippocampal neuroinflammation in adolescent mice treated with binge drinking.We demonstrated that the administration of mesenchymal stem cell-derived extracellular vesicles ameliorated the activation of the hippocampal NLRP3 inflammasome complex and other NLRs inflammasomes(e.g.,pyrin domain-containing 1,caspase recruitment domain-containing 4,and absent in melanoma 2,as well as the alterations in inflammatory genes(interleukin-1β,interleukin-18,inducible nitric oxide synthase,nuclear factor-kappa B,monocyte chemoattractant protein-1,and C–X3–C motif chemokine ligand 1)and miRNAs(miR-21a-5p,miR-146a-5p,and miR-141-5p)induced by binge-like ethanol treatment in adolescent mice.Bioinformatic analysis further revealed the involvement of miR-21a-5p and miR-146a-5p with inflammatory target genes and NOD-like receptor signaling pathways.Taken together,these findings provide novel evidence of the therapeutic potential of MSC-derived EVs to ameliorate the hippocampal neuroinflammatory response associated with NLRP3 inflammasome activation induced by binge drinking in adolescence.

基于ADE优化的IPMSM全速域无传感器控制

为了实现内置式永磁同步电机(IPMSM)全速域的无传感器控制和切换速域的平滑过渡,提出了一种基于自适应差分进化(ADE)算法优化的复合控制方法。分别在零低速域、中高速域采用旋转高频电压注入法和滑模观测器法来对电机转速和转子位置进行估算,并在切换速域采用基于ADE算法的权重系数优化法来实现上述两种控制方法的平滑切换,从而实现IPMSM全速域无传感器控制。仿真结果表明:提出的复合控制方法能够实现电机全速域的无感控制和切换速域的平滑过渡,且具有良好的稳定性。

儿童维生素AD滴剂,这样吃才对

众所周知,维生素A、D对孩子的生长发育至关重要。而补充维生素A、D,最好选择专门的维生素AD制剂,比如维生素AD滴剂。但许多家长对其又不甚了解,有诸多疑问。以下,笔者将一一进行解答。

ADS-B信号在对流层大气波导中的传播性能

对流层大气环境存在特殊大气结构“大气波导”,可形成电波超视距传播或产生雷达盲区等。目前,通过雷达、GNSS信号等可以对大气波导进行一定程度的反演探测,但均存在一定的不足。ADS-B信号具有应用范围广、信号密度大、实时性高等特点,为此提出利用ADS-B信号受到不同大气环境影响后能量损耗不同的特点对ADS-B信号与对流层大气环境关联性进行分析研究。以武汉地区ADS-B信号数据为例,基于抛物方程传播理论对路径损耗进行仿真分析,并进行了实验验证。结果表明:ADS-B接收信号与仿真结果存在线性相关性并给出线性表述,为后续利用ADS-B信号反演大气波导提供参考依据。

星基ADS-B系统空天链路的建模与仿真

星基广播式自动相关监视(ADS-B,automatic dependent surveillance-broadcast)系统是一种新型的航空器监视技术,在未来空中交通管理系统中具有广阔的应用前景。为了深入研究星基ADS-B系统中航空器到卫星的空天链路通信性能,将专业软件Matlab和STK(system tool kit)有效联合,构建符合国际标准的星基ADS-B空天链路完整模型;通过离散事件动态交互模拟ADS-B消息的发送与接收全过程,最后统计得出体现星基ADS-B空天链路通信性能的消息识别概率(POI,possibility of identify)、消息检测概率(POD,possibility of detective)、信号接收功率、信号冲突概率、卫星覆盖范围等指标。仿真结果表明,随着区域内航空器数量上升,POI、POD下降,消息冲突概率上升。

Cross-protective effect of acid adaptation on ethanol tolerance in Salmonella Enteritidis

Cross protection can undermine the effectiveness of control measures on foodborne pathogens,and therefore brings major implications for food safety.In this work,the capacity of Salmonella Enteritidis to mount ethanol tolerance following acid adaptation was characterized by analysis of cell viability and cell membrane property.It was observed that preadaptation to pH 4.5 significantly(P<0.05)increased the tolerance of log-phase cells to ethanol;in contrast,stationary-phase cells displayed reduced ethanol tolerance after acid adaptation.However,acid adaptation did not cause cell leakage and morphological change in both log-phase and stationary-phase S.Enteritidis.Fatty acid analysis further revealed that the amount of C_(14:0),C_(17:0 cyclo) and C_(19:0 cyclo) fatty acids was increased,while that of C_(16:1ω7c) and C_(18:1ω7c) fatty acids was decreased,respectively,in response to acid adaptation,regardless of bacterial growth phase.Notably,acid adaptation significantly(P<0.05)increased the proportion of C_(16:0) fatty acid in log-phase cells,but this effect did not occur in stationary-phase cells.Moreover,exogenous addition of C_(16:0) fatty acid to stationary-phase acid-adapted cultures was able to enhance bacterial ethanol tolerance.Taken together,C_(16:0) fatty acid is involved in the growth-phase-dependent protective effect of acid adaptation on ethanol tolerance in S.Enteritidis.

基于迁移学习-元学习的ADS-B攻击分类研究

准确分类通航领域ADS-B攻击类型,采取预防攻击措施,对保障通航运行安全性具有重要意义。针对通航领域ADS-B攻击数据样本少,提出一种基于迁移学习-元学习的ADS-B攻击分类模型。该模型将迁移学习与深度卷积自编码器相结合,建立ADS-B攻击特征提取模型,提取数据样本的攻击有效特征表示,并运用元学习策略在特征空间中实现ADS-B攻击准确分类。实例研究表明,基于迁移学习-元学习的攻击分类模型可有效分类小样本ADS-B攻击,且正确率在95%以上。

基于多时间特征融合网络的ADS-B实采信号分离

不同于以往单天线广播式自动相关监视(Automatic Dependent Surveillance-Broadcast,ADS-B)信号分离中利用仿真的ADS-B信号制作数据集,将单天线接收的真实飞机发射的ADS-B原始信号通过调整信号起始时间以及功率并人为增加噪声来制作数据集。为了提高信号分离的时域波形精度,提出一种多分辨率多时间特征融合重采样(Multi-Temporal fusion Resampling of Multi-Resolution Features,MTRM-RF)网络,通过卷积将信号转化成不同采样率的信号并分别使用多层堆叠逐渐膨胀的一维卷积提取不同时间间隔的特征,以获得更多的时间信息。对多种基于深度学习的语音分离网络进行比较发现,MTRM-RF网络能够有效地融合ADS-B信号的不同采样率、不同时间间隔采样点的特征进行训练。并且随着训练集数据量的增加,分离信号的平均解码正确率达到88.39%,证明该网络可有效分离单天线实采的ADS-B交织信号。

基于AD与TRIZ的加工中心主轴松拉刀机构优化设计

数控加工中心在加工过程中常出现主轴松刀力不足或无法松刀的现象。针对此问题,通过TRIZ系统组件分析明确现有松拉刀机构各组件间作用关系,利用因果链分析得出影响松刀的根本原因,最终应用TRIZ理论中的物场模型分析方法和AD独立性原理提出优化设计方案。根据新方案计算出实际工况下的主轴松刀力和螺杆强度,并对松刀杆进行建模和仿真。结果表明:最大位移量为6.995μm,最大应力为45.24 MPa,符合结构设计要求。最后,经过现场实物测试,当液压力为5 MPa时,松刀行程、松刀力以及打刀量均符合生产要求,验证了优化设计方案的合理性。

白菜型冬油菜BrADS2基因的克隆、表达分析与亚细胞定位

【目的】探究白菜型冬油菜(Brassica rapa L.)脂肪酸去饱和酶ADS2(Δ9 fatty acid desaturase)基因与抗寒性的关系。【方法】基于前期转录组结果,采用一步定向克隆法得到BrADS2基因;构建GFP融合表达载体,通过注射法在烟草下表皮细胞进行瞬时转化,同时采用农杆菌侵染法侵染‘中双11号’;利用qRT-PCR技术,检测抗寒性不同的白菜型冬油菜品种叶片中ADS2基因的表达模式,并对低温下冬油菜的形态变化和抗氧化酶活性、电导率含量进行分析。【结果】白菜型冬油菜BrADS2基因可编码307个氨基酸,该基因编码的蛋白具有亲水性特性;qRT-PCR结果显示,BrADS2基因的表达量呈先升后降的单峰型变化,且在-4℃时表达量达到峰值;亚细胞定位结果显示BrADS2蛋白在细胞质和细胞膜上表达;低温处理下3个品种叶片的相对电导率、抗氧化物酶活性均显著上升,强抗寒品种抗氧化酶活性高于弱抗寒品种,电导率却相反;农杆菌介导侵染‘中双11号’下胚轴后获得15株转基因阳性苗,且转基因油菜阳性植株叶中的BrADS2基因表达量均显著高于野生型。【结论】推测BrADS2基因在白菜型冬油菜膜脂不饱和调节中起重要作用,揭示了ADS2基因与冬油菜抗低温胁迫的关系。

基于改进型多斜Ⅲ技术的7位半AD转换器设计

高精度测试仪器在环境试验中扮演着重要角色,而积分型AD转换器被广泛的应用在高精度测试仪器中。针对传统型积分型AD转换器转换速率较低的问题,提出了一种提高转换速率的改进型多斜ⅢAD转换器,详细的介绍了其原理和设计思路。该转换器以单片机与CPLD一同控制积分型ADC,在积分末尾利用单片机片内ADC测量积分器的残留电压,以达到提高转换速率的目的。经理论分析该AD转换器比传统型转换速率快836倍,分辨率可达到31位,在±10V直流电压测量中可实现7位半分辨率。

Loading CuO on the surface of MgO with low-coordination basic O^(2-)sites for effective enhanced CO_(2) capture and photothermal synergistic catalytic reduction of CO_(2) to ethanol

The higher capacity of CO_(2)adsorption on the surface of magnesium oxide(MgO)with low-coordination O^(2-)sites would effectively enhance the catalytic reduction of CO_(2).Herein,a series of copper oxide(CuO)and MgO composites with different mass ratios have been prepared by hydrothermal method and used for photothermal synergistic catalytic reduction of CO_(2)to ethanol.The catalyst with CuO mass ratio of 1.6% shows the best yield(15.17μmol·g^(-1)·h^(-1))under 3 h Xenon lamp illumination.The improved performance is attributable to the loose nano-sheet structure,uniform dispersion of active sites,the increased specific surface area,medium-strength basicity,the high separation efficiency of electrons and holes,and the formation of Mg-O-Cu species.The synthesized CuO and MgO composites with loose nano-sheet structure facilitate the diffusion of reactants CO_(2),so an excellent CO_(2)adsorption performance can be obtained.Meanwhile,the introduction of CuO in the form of bivalence provides higher specific surface area and porosity,thus obtaining more active sites.More importantly,the Mg-O-Cu species make the donation of electrons from MgO to CO_(2)easier,resulting in the breaking of the old Mg-O bond and the formation of C-O bond,thus promoting the adsorption and conversion of CO_(2)to ethanol.

基于FPGA与AD9786的调制解调电路的设计

谐振式光学陀螺因其高理论精度、小型化以及高稳定性受到了国内外的强烈关注。针对于谐振式光学陀螺检测信号微弱的特点,需要对该信号进行调制解调,以实现陀螺的稳定输出,设计了一种基于FPGA和AD9786的高精度模拟信号源,该信号以FPGA作为核心控制单元,AD9786作为数模转换器,实现16位的高精度DA转换,通过上位机实现指令的通信过程,可实现不同频率的交流信号。该实验结果表明,该系统符合陀螺测试系统调制解调要求,通过上位机对不同输出信号进行测试,且测试结果无纹波时输出噪声Vrms269μV,交流信号精度达到0.01%,最高频率可达到2M,稳定性高。

基于AD7616的16通道数据采集系统设计

针对传统数据采集系统因通道不足或数据量过大,无法满足多通道同步采集的问题,设计了一种基于AD7616的16通道数据采集系统。系统以Xilinx系列FPGA作为主控芯片,ADI公司的AD7616作为模数转换芯片,DDR3 SDRAM作为缓存单元。介绍了各个模块硬件的设计思路,重点介绍了FPGA控制AD7616模数转换模块、DDR3 SDRAM缓存模块的软件程序设计,并对系统的多通道采样功能、同步性能以及实际水下超声信号的采集能力进行了实验验证,结果表明,系统可以完成水下超声信号的多通道同步采集。

Ethanol changes Nestin-promoter induced neural stem cells to disturb newborn dendritic spine remodeling in the hippocampus of mice

Adolescent binge drinking leads to long-lasting disorders of the adult central nervous system,particularly aberrant hippocampal neurogenesis.In this study,we applied in vivo fluorescent tracing using NestinCreERT2::Rosa26-tdTomato mice and analyzed the endogenous neurogenesis lineage progression of neural stem cells(NSCs)and dendritic spine formation of newborn neurons in the subgranular zone of the dentate gyrus.We found abnormal orientation of tamoxifen-induced tdTomato+(tdTom^(+))NSCs in adult mice 2 months after treatment with EtOH(5.0 g/kg,i.p.)for 7 consecutive days.EtOH markedly inhibited tdTom^(+)NSCs activation and hippocampal neurogenesis in mouse dentate gyrus from adolescence to adulthood.EtOH(100 mM)also significantly inhibited the proliferation to 39.2%and differentiation of primary NSCs in vitro.Adult mice exposed to EtOH also exhibited marked inhibitions in dendritic spine growth and newborn neuron maturation in the dentate gyrus,which was partially reversed by voluntary running or inhibition of the mammalian target of rapamycinenhancer of zeste homolog 2 pathway.In vivo tracing revealed that EtOH induced abnormal orientation of tdTom+NSCs and spatial misposition defects of newborn neurons,thus causing the disturbance of hippocampal neurogenesis and dendritic spine remodeling in mice.

脉冲电流对轧辊用AD180高碳半钢材料力学性能及组织的影响

为分析电流处理对轧辊材料的影响规律,通过改变电流密度和处理时间来调整AD180高碳半钢的微观组织和力学性能。使用万能拉伸试验机对电流处理后的试样进行单轴拉伸实验,并对试样进行SEM断口截面分析和EBSD微观表征,研究其力学性能和微观组织的变化规律。拉伸结果表明,在电流密度11.88 A·mm-2、通电5 min时,试样的综合性能最好,屈服强度提高6.5%,抗拉强度提高12.1%,伸长率提高了25.4%。通过断口截面分析发现,拉伸试样均为脆性断裂,未通电试样存在大量孔洞缺陷,而合适的电流密度和通电时间可以促进试样内部孔洞缺陷的“愈合”,其中,电流密度为11.88 A·mm^(-2)、通电5 min时,试样断口上的缺陷最少。EBSD微观表征结果表明,脉冲电流使试样在较低温度下发生了再结晶,细化了晶粒。由此可见,脉冲电流可以改善试样内部的组织结构和治愈微缺陷,提高其综合力学性能。

基于动态离散模型的机场ADS-B攻击威胁影响研究

随着航空业信息技术的发展,空中交通管制系统面临着多种网络攻击的威胁。广播式自动相关监视(ADS-B)系统因其明文广播的数据传输方式,存在着被网络攻击的安全问题。依据“等待降落-降落-停泊-排队起飞-起飞”的航班运行全流程,建立了WLPQD动态离散模型,研究机场流量和航班延误。模型引入了系统冗余能力、处理速率等参数,模拟了攻击场景;通过受影响飞机数量和延误时间等指标研究了机场航班延误的传播影响。模型展示了ADS-B消息注入攻击对降落、起飞航班造成的延误,提出了两种攻击缓解方法。结果表明,延误规模的大小与攻击强度呈现正相关,且攻击对起飞航班的延误影响更大;提升对“幽灵飞机”和合法飞机的处理速率都可提升机场系统的抗毁性,但前者对提升机场系统冗余能力的效果更加显著。所做研究为机场系统抵御网络攻击、增强抗毁性提供了决策分析的参考依据。