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关键词： Aluminium composite   Response surface methodology   ANOVA   CCD   SiC  

摘要： Aluminum matrix composites are used in high-temperature applications such pistons, cylinder heads, and blocks for automobile engines. As a result, it's important to evaluate the performance of an aluminium metal matrix composite at high *** this study, we tried to find out the tribological behaviour of composite Al-SiC at elevated temperatures. The current study examines the wear behaviour of an Al-SiC composite with 20 percent SiC and 100 mu m size powder reinforcement at different temperatures. The composite specimens are made using the centrifugal casting method, which results in considerable segregation of reinforcement on the composite's outer layer, which is exposed to wear. Response surface methodology (RSM) method is used to create experimental designs and for mathematical equation development. The wear test is carried out on a pin-on-disc device with a heating *** study reveals that temperature has a significant impact on the rate of wear. The wear is predicted using a mathematical model based on regression. The scanning electron microscope (SEM) is used to investigate the worn-out surface, X ray diffraction (XRD) test were performed to analyse the purity and verification of particle size. The experiments are carried out in accordance with ASTM guidelines. As a result, at elevated temperature wear of composite increases as temperature increases and above 300 degrees C high wear have been obseved. According to ANOVA result, Temperature contributes 70.87%, load 4.51% and sliding distance 17.44% on wear. Temperature influence most if compare with sliding distance and load.

关键词： Bismuth  

摘要： In the current study, the catalyst for the decolorization of methyl orange (MO) was developed HAp-rGO by the aqueous precipitation approach. Then, bismuth(0) nanoparticles (Bi NPs), which expect to show high activity, were reduced on the surface of the support material (HAp-rGO). The obtained catalyst was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. The parameters that remarkably affect the decolorization process (such as time, initial dye concentration, NaBH4 amount, and catalyst amount) have been examined by response surface methodology (RSM), an optimization method that has acquired increasing significance in recent years. In the decolorization of MO, the optimum conditions were identified as 2.91 min, Co: 18.85 mg/L, NaBH4 amount: 18.35 mM, and Bi/HAp-rGO dosage: 2.12 mg/mL with MO decolorization efficiency of 99.60%. The decolorization process of MO with Bi/HAp-rGO was examined in detail kinetically and thermodynamically. Additionally, the possible decolorization mechanism was clarified. The present work provides a new insight into the use of the optimization process for both the effective usage of Bi/HAp-rGO and the catalytic reduction of dyes. © The Author(s) 2024.

关键词： Aluminium composite   MMCs   RSM   CCD   GRA  

摘要： This research investigation explores the wear and coefficient of friction (CoF) performance of aluminium silicon carbide composite (Al-SiC) at elevated temperature. This research aims to find out the effect of temperature on wear of composite for higher temperature application of Al-SiC composite like cylinder liners, cylinder head and block, pistons, etc. Al-SiC 20% composite made by centrifugal casting, Response surface method central composite design model design used to perform experiments by varying elevated temperature (100-300 degrees C), load (10-20 N) and sliding distance (500-1000 m). Wear and CoF were calculated by experiment and for optimization Grey relational analysis optimization tool were applied. The wear test were performed by pin-on-disc tester machine with heating chamber to create temperature at the time of wear, the study reveals that the temperature influence wear and CoF if compare with normal condition, elevated temperature increases the wear rate. Scanning electron microscope images were taken to study the worn-out surfaces of composite.

关键词： 无线传感器网络   数据融合技术   环境监测   智能交通   农业   工业制造  

摘要： 无线传感器网络中的数据融合技术是一种将多个传感器节点采集到的数据进行整合、分析和处理的技术.该技术可以提高数据采集的准确性和实时性,为各种应用提供科学依据和支持.本文从无线传感器网络和数据融合技术的概述入手,详细介绍了无线传感器网络中的数据融合技术,并以环境监测、智能交通、农业和工业制造4个领域为例,阐述了数据融合技术在不同领域的应用,旨在为相关研究人员提供有效参考.

关键词： 无人机   恶臭气体   多传感器信息融合   恶臭强度   广义动态模糊神经网络  

摘要： 针对日益严重的恶臭气体污染，人工嗅辨法对检测人员要求高且工作效率低，传统仪器又会遇到检测点不易接近或安装条件的限制，因此设计一款无人机搭载基于多传感器信息融合算法的传感器阵列系统的新方法来检测恶臭气体的浓度。本文中采用广义动态模糊神经网络对传感器检测到的数据进行采集与处理，然后根据韦伯-费希纳定律得出恶臭强度等级。通过实验对恶臭污染源进行气体浓度检测，实验表明：恶臭检测系统的检测结果与人工嗅辨结果基本吻合，满足恶臭检测的相关要求，这样大大节省了人力物力，在恶臭环境检测中具有良好的应用前景。

关键词： Stars  

摘要： Employing VI images of NGC 2419 acquired over 17 years, light curves for most of the known variables in the field of the cluster are produced. A cluster membership analysis for about 3100 stars in the cluster field with proper motions from Gaia-DR3, revealed the presence of member stars as far as 140 pc from the cluster center and enabled the construction of a cleaner CMD free of field stars. It was found that RRab and RRc stars share the inter-order region in the instability strip, which is unusual for OoII clusters. Theoretical considerations confirm that Pop II cepheids are descendants of extreme ZAHB blue tail stars with very thin envelopes of about 10% of the total mass. Member RR Lyrae stars were employed to calculate independent estimates of the mean cluster metallicity and distance;we found [Fe/H]UV = −1.90 ± 0.27 and D = 86.3 ± 5.0 kpc from the RRab and [Fe/H]UV = −1.88 ± 0.30 and D = 83.1 ± 8.1 kpc from the RRc light curves. Copyright © 2024, The Authors. All rights reserved.

关键词： 损失模式共振   TiO   光纤湿度传感器   折射率   湿敏材料  

摘要： 提出一种高分子湿敏材料涂覆的光纤损失模式共振(lossy mode resonance， LMR)湿度传感器，以多模光纤为基底，使用层层自组装(layer-by-layer assembled， LBL)方法在纤芯上沉积二氧化钛(titanium dioxide， TiO2)以激发LMR效应，在理论和实验方面验证了其对于折射率变化的敏感性，以聚乙烯醇(polyvinyl alcohol， PVA)和聚酰亚胺(polyimide， PI)分别作为湿敏材料制作LMR湿度传感器，通过观察吸收光谱中共振峰的偏移来实现对周围环境湿度变化的监测。实验结果表明，两种传感器都能实现湿度的传感，且表现出相近的传感特性，其中PVA传感器在60%RH-90%RH湿度区间，灵敏度最高可达到2.94nm/%RH，两种传感器湿度灵敏度高、可逆性、重复性好，在湿度检测领域有广泛的研究和应用前景。

摘要： Employing \emph{VI} images of NGC 2419 acquired over 17 years, light curves for most of the known variables in the field of the cluster are produced. A cluster membership analysis for about 3100 stars in the cluster field with proper motions from $Gaia$-DR3, revealed the presence of member stars as far as 140 pc from the cluster center and enabled the construction of a cleaner CMD free of field stars. It was found that RRab and RRc stars share the inter-order region in the instability strip, which is unusual for OoII clusters. Theoretical considerations confirm that Pop II cepheids are descendants of extreme ZAHB blue tail stars with very thin envelopes of about 10\% of the total mass. Member RR Lyrae stars were employed to calculate independent estimates of the mean cluster metallicity and distance; we found [Fe/H]$_{\rm UV}= -1.90 \pm 0.27$ and $D=86.3 \pm 5.0$ kpc from the RRab and [Fe/H]$_{\rm UV}= -1.88 \pm 0.30$ and $D=83.1 \pm 8.1$ kpc from the RRc light curves.

关键词： 光通信   无源光互连   光互连数据中心   三偏振复用   阵列波导光栅  

摘要： 在基于阵列波导光栅的光互连数据中心中，每个节点可以接收由任意波长携带的多个信号，如果节点无法分离信号，则可能导致信道冲突。提出了一种三信道接收方案，允许每个节点同时接收任意一组三个波长的信号（即防冲突）。任意两个信号之间的偏振差为60°。在接收时，复合信号被分到三个偏振分束器，然后经过三个光电检测器。每个偏振分束器滤除一个信号，随后的光电检测器检测另外两个信号。三个信号可以通过在电域或数字域中的算术运算从检测结果中复原。改进后的方案不需要波长可调谐接收器或冗余接收器并实现了单个节点可以同时接收任意一组三个波长的信号。仿真结果验证了改进后方案的可行性。

关键词： 光学异常透射   金属光栅   塔姆等离激元   类法布里-珀罗共振  

摘要： 为了采用易于直接激发的塔姆等离激元(Tamm plasmon polaritons， TPPs)实现透射增强现象，本文提出了一种由一维金属光栅覆盖分布式布拉格反射镜(distributed bragg reflector， DBR)构成的层状结构．采用有限元法分析了入射光波在DBR-金属交界面上激发TPPs并产生能量高度局域的物理过程．研究表明入射TM光波在金属-DBR交界面上激发的TPPs可以有效地激发金属狭缝内的SPPs模式，当SPPs模式在狭缝内满足类FP谐振的条件就可以使入射光波在该结构中的产生透射增强．通过分析狭缝宽度及其占空比对透射谱峰的定量影响．结果显示：周期确定时随着狭缝宽度的增大，峰值透射率则呈现先增大而后减小的变化趋势；宽度确定时随着占空比的增加，峰值透射率会呈现单调降低的变化趋势，而透射峰中心波长呈现近似线性蓝移趋势，这为灵活调节异常透射的中心波长提供了一种有效手段．