Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, thre...Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.展开更多
介绍了一种基于AC-link技术的并联谐振高压电源的拓扑电路,该结构结合准谐振的工作模式能够实现高功率因数和高效率;采用了基于状态平面图对并联谐振电路的分析方法,该方法相比传统的基波等效分析法具有求解简单、直观、精确和负载适用...介绍了一种基于AC-link技术的并联谐振高压电源的拓扑电路,该结构结合准谐振的工作模式能够实现高功率因数和高效率;采用了基于状态平面图对并联谐振电路的分析方法,该方法相比传统的基波等效分析法具有求解简单、直观、精确和负载适用范围大的特点,并给出了相应推导过程;给出了输出电压为25 k V,电流为1 A的变换器的分析和谐振参数设计。最后进行了仿真,仿真结果表明,基于高频交流链接并联谐振拓扑和基于状态平面图法的控制能够稳定输出电压(<1%),实现零电流开关,三相输入电流谐波较低(THD<12.5%)与三相电压基本同相位,功率因数为0.99。展开更多
近年来,随着普适计算概念的深入人心,智能感知技术已成为研究者们关注的焦点,且基于WiFi的非接触式感知因其优秀的普适性、低廉的部署成本以及良好的用户体验越来越受到学术界和工业界的青睐.典型的WiFi非接触式感知工作有手势识别、呼...近年来,随着普适计算概念的深入人心,智能感知技术已成为研究者们关注的焦点,且基于WiFi的非接触式感知因其优秀的普适性、低廉的部署成本以及良好的用户体验越来越受到学术界和工业界的青睐.典型的WiFi非接触式感知工作有手势识别、呼吸检测、入侵检测、行为识别等,这些工作若实际部署,需首先避免其他无关区域中无关行为的干扰,因此需要判断目标是否进入到特定的感知区域中.这意味着系统应具备精准判断目标在界线哪一侧的能力,然而现有工作未能找到一个可以对某个自由设定的边界进行精确监控的方法,这阻碍了WiFi感知应用的实际落地.基于这一关键问题,从电磁波衍射的物理本质出发,结合菲涅尔衍射模型(Fresnel diffraction model),找到一种目标穿越link(收发设备天线的连线)时的信号特征(Rayleigh distribution in Fresnel diffraction model,RFD),并揭示该信号特征与人体活动之间的数学关系;之后以link作为边界,结合天线间距带来的波形时延以及AGC(automatic gain control)在link被遮挡时的特征,通过越线检测实现对边界的监控.在此基础上,还实现了两个实际应用,即入侵检测系统和居家状态监测系统,前者的精确率超过89%、召回率超过91%,后者的准确率超过89%.在验证所提边界监控算法的可用性和鲁棒性的同时,也展示了所提方法与其他WiFi感知技术相结合的巨大潜力,为WiFi感知技术的实际部署提供了思考方向.展开更多
An operational backbone network is connected with many routers and other devices. Identifying faults in the network is very difficult, so a fault localization mechanism is necessary to identify fault and alleviate it ...An operational backbone network is connected with many routers and other devices. Identifying faults in the network is very difficult, so a fault localization mechanism is necessary to identify fault and alleviate it and correct the faults in order to reduce the network performance degradation. A risk model needs to be devised based on the dynamic database by creating alternate path and the network is reconfigured by identifying dynamic paths. In this paper, an on-demand link state routing approach is used for handling failures in IP backbone networks and a localization algorithm is used to improve QOS parameters based on threshold value of gateway. It is proved that on-demand link state routing guarantees loop-free forwarding to reachable destinations regardless of the number of failures in the network, and in case of localization algorithm using modification process packet loss is avoided based on threshold value of gateway. Heuristic algorithm is also used for reconfiguration of dynamic path for effective fault localization. In this paper, in order to change the traffic condition, reconfiguration strategic is dynamically used. Dijikstra’s shortest path algorithm has been used to determine the shortest path between node pairs. Using risk modeling mechanism, a small set of candidate faults is identified. The concept of Fault Localization is used to minimize the fault occurring in the node and sends original path to node pairs. The localization algorithm based on MODIFICATION PROCESS, packet loss is avoided in the network by checking threshold value of gateway. If the threshold value is maximum, router directly forwards the packet to destination through gateway and if the threshold value is minimum, router compresses the packet and forwards the packet to destination with notification via gateway.展开更多
以丙烯腈(AN)为单体,聚丙二醇双甲基丙烯酸酯(PPGDMA)为交联剂制备了丁二腈(SN)增塑的塑性PAN-co-PPGDMA交联聚合物-双三氟甲基磺酰亚胺锂(Li TFSI)复合电解质poly-SN40。研究表明,poly-SN40具有较宽的电化学窗口(0-5.2 V vs Li/Li^(+)...以丙烯腈(AN)为单体,聚丙二醇双甲基丙烯酸酯(PPGDMA)为交联剂制备了丁二腈(SN)增塑的塑性PAN-co-PPGDMA交联聚合物-双三氟甲基磺酰亚胺锂(Li TFSI)复合电解质poly-SN40。研究表明,poly-SN40具有较宽的电化学窗口(0-5.2 V vs Li/Li^(+))和较高的室温离子电导率(1.27 mS/cm);组装的锂电池Li/ploy-SN40/LiFePO4的充放电实验表明,在0.5 m A/cm^(2)的电流密度下,电池能够正常、安全地循环使用;电池在0.2 C倍率下室温循环比容量超过133.5 m Ah/g,在200次循环后容量保持率为92%,表现出98.3%的优异平均库仑效率。展开更多
针对舱内无线光传输系统多种干扰问题,比如多径损耗和突发干扰等,提出一种基于链路状态的自适应干扰消除技术,该方法分析舱内链路状态,完成链路状态估计,采用环境自适应的变遗忘因子RLS(recursive least squares)算法,针对不同链路状态...针对舱内无线光传输系统多种干扰问题,比如多径损耗和突发干扰等,提出一种基于链路状态的自适应干扰消除技术,该方法分析舱内链路状态,完成链路状态估计,采用环境自适应的变遗忘因子RLS(recursive least squares)算法,针对不同链路状态采取差异化的干扰消除策略,以提高舱内通信质量。仿真结果表明:该算法在尽力避免增加算法复杂度的条件下,相对于传统固定遗忘因子算法,在平稳状态下优先保证传输的误码性能,在链路状态变化时具有更好的收敛性能,灵活适应了舱内多种传输情况。展开更多
The purpose of this article is to propose Stability-based Energy-Efficient Link-State Hybrid Routing(S-ELHR),a low latency routing proto-col that aims to provide a stable mechanism for routing in unmanned aerial vehic...The purpose of this article is to propose Stability-based Energy-Efficient Link-State Hybrid Routing(S-ELHR),a low latency routing proto-col that aims to provide a stable mechanism for routing in unmanned aerial vehicles(UAV).The S-ELHR protocol selects a number of network nodes to create a Connected Dominating Set(CDS)using a parameter known as the Stability Metric(SM).The SM considers the node’s energy usage,connectivity time,and node’s degree.Only the highest SM nodes are chosen to form CDS.Each node declares a Willingness to indicate that it is prepared to serve as a relay for its neighbors,by employing its own energy state.S-ELHR is a hybrid protocol that stores only partial topological information and routing tables on CDS nodes.Instead of relying on the routing information at each intermediary node,it uses source routing,in which a route is generated on-demand,and data packets contain the addresses of the nodes the packet will transit.A route recovery technique is additionally utilized,which first locates a new route to the destination before forwarding packets along it.Through simulation for various network sizes and mobility speeds,the efficiency of S-ELHR is shown.The findings demonstrate that S-ELHR performs better than Optimized Link State Routing(OLSR)and Energy Enhanced OLSR(EE-OLSR)in terms of packet delivery ratio,end-to-end delay,and energy consumption.展开更多
The presence of aflatoxin-producing fungi in foods consumed by humans and animals has often resulted in the health hazards and even death. Aflatoxin contaminations of garri sold in some markets of Benue State, Nigeria...The presence of aflatoxin-producing fungi in foods consumed by humans and animals has often resulted in the health hazards and even death. Aflatoxin contaminations of garri sold in some markets of Benue State, Nigeria, were studied, to ascertain the health implications on the consumers. Sixty garri samples comprising of 30 white garri and 30 yellow garri respectively were studied. The garri samples were ground to a particle size of 250 μm using a sterile blender. The total aflatoxin was extracted using 70% (v/v) methanol. The total aflatoxin concentration was detected and quantified using the Enzyme-Linked Immunosorbent Assay technique. The results showed that overall, 76.67% of the white garri samples and 80% of the yellow garri samples were aflatoxin positive. The total aflatoxin concentration in white garri ranged from 0.3 μg/kg to 2.4 μg/kg and 0.2 to 2.4 μg/kg in yellow garri respectively. The total mean aflatoxin across the States recorded was 2.96 μg/kg in white garri and 3.07 μg/kg in yellow garri. All the aflatoxin-positive garri samples of both the white and yellow garri were within the NAFDAC permissible aflatoxin level. Even though the aflatoxins are within the approved standard consumable limits, the continuous consumption of these doses over a long period of time could lead to the accumulation of these toxins in the body. These may eventually constitute a toxic health challenge.展开更多
优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控...优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控制开销,浪费短波有限的带宽资源,导致网络通信性能急剧下降。其次,受到地形地貌、天线方向和接收性能的个体差异等影响,造成无线链路不稳定,导致网络中存在非对称链路,增加了通信端到端时延。为此,提出了一种低时延的短波自组网OLSR协议。该协议在执行MPR(Multipoint Relay)选择算法时综合考虑了节点的连接度和链路可靠性,在优化MPR节点个数的同时选择链路可靠性较大的节点作为MPR节点,在进行路由选择时能够利用网络中的非对称链路。仿真结果表明,该协议能优化数据包投递成功率、吞吐量、端到端时延和网络控制开销等性能指标。展开更多
由于光网络中的路径跳数过多或距离偏大,使寻找可用的频谱资源难度增加,导致光网络动态频谱利用率降低、网络效益较少且阻塞率较高,为此,提出基于蛙跳博弈优化算法的光网络动态频谱分配方法。采用OHM(Optimized Link State Routing Prot...由于光网络中的路径跳数过多或距离偏大,使寻找可用的频谱资源难度增加,导致光网络动态频谱利用率降低、网络效益较少且阻塞率较高,为此,提出基于蛙跳博弈优化算法的光网络动态频谱分配方法。采用OHM(Optimized Link State Routing Protocol using the Highway Model)路由算法,选择与业务请求对应,且满足跳数最小、调制等级最高的候选路径,找到可用的频谱资源。根据获取的频谱资源,在光网络中将最大频隙号在所有链路中最小作为目标,构建光网络动态频谱分配的目标函数。并在约束条件下,采用蛙跳博弈优化算法对目标函数求解,获取的解即为光网络动态频谱分配最优结果。实验结果表明,该方法的阻塞率低、频谱利用率高、网络收益高,具有实用性。展开更多
By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three...By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three-qubit states on the surface of a trivial torus. Thus, we obtain eight knotted pictures 121 linkage on the ordinary plane.展开更多
文摘Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.
文摘介绍了一种基于AC-link技术的并联谐振高压电源的拓扑电路,该结构结合准谐振的工作模式能够实现高功率因数和高效率;采用了基于状态平面图对并联谐振电路的分析方法,该方法相比传统的基波等效分析法具有求解简单、直观、精确和负载适用范围大的特点,并给出了相应推导过程;给出了输出电压为25 k V,电流为1 A的变换器的分析和谐振参数设计。最后进行了仿真,仿真结果表明,基于高频交流链接并联谐振拓扑和基于状态平面图法的控制能够稳定输出电压(<1%),实现零电流开关,三相输入电流谐波较低(THD<12.5%)与三相电压基本同相位,功率因数为0.99。
文摘近年来,随着普适计算概念的深入人心,智能感知技术已成为研究者们关注的焦点,且基于WiFi的非接触式感知因其优秀的普适性、低廉的部署成本以及良好的用户体验越来越受到学术界和工业界的青睐.典型的WiFi非接触式感知工作有手势识别、呼吸检测、入侵检测、行为识别等,这些工作若实际部署,需首先避免其他无关区域中无关行为的干扰,因此需要判断目标是否进入到特定的感知区域中.这意味着系统应具备精准判断目标在界线哪一侧的能力,然而现有工作未能找到一个可以对某个自由设定的边界进行精确监控的方法,这阻碍了WiFi感知应用的实际落地.基于这一关键问题,从电磁波衍射的物理本质出发,结合菲涅尔衍射模型(Fresnel diffraction model),找到一种目标穿越link(收发设备天线的连线)时的信号特征(Rayleigh distribution in Fresnel diffraction model,RFD),并揭示该信号特征与人体活动之间的数学关系;之后以link作为边界,结合天线间距带来的波形时延以及AGC(automatic gain control)在link被遮挡时的特征,通过越线检测实现对边界的监控.在此基础上,还实现了两个实际应用,即入侵检测系统和居家状态监测系统,前者的精确率超过89%、召回率超过91%,后者的准确率超过89%.在验证所提边界监控算法的可用性和鲁棒性的同时,也展示了所提方法与其他WiFi感知技术相结合的巨大潜力,为WiFi感知技术的实际部署提供了思考方向.
文摘An operational backbone network is connected with many routers and other devices. Identifying faults in the network is very difficult, so a fault localization mechanism is necessary to identify fault and alleviate it and correct the faults in order to reduce the network performance degradation. A risk model needs to be devised based on the dynamic database by creating alternate path and the network is reconfigured by identifying dynamic paths. In this paper, an on-demand link state routing approach is used for handling failures in IP backbone networks and a localization algorithm is used to improve QOS parameters based on threshold value of gateway. It is proved that on-demand link state routing guarantees loop-free forwarding to reachable destinations regardless of the number of failures in the network, and in case of localization algorithm using modification process packet loss is avoided based on threshold value of gateway. Heuristic algorithm is also used for reconfiguration of dynamic path for effective fault localization. In this paper, in order to change the traffic condition, reconfiguration strategic is dynamically used. Dijikstra’s shortest path algorithm has been used to determine the shortest path between node pairs. Using risk modeling mechanism, a small set of candidate faults is identified. The concept of Fault Localization is used to minimize the fault occurring in the node and sends original path to node pairs. The localization algorithm based on MODIFICATION PROCESS, packet loss is avoided in the network by checking threshold value of gateway. If the threshold value is maximum, router directly forwards the packet to destination through gateway and if the threshold value is minimum, router compresses the packet and forwards the packet to destination with notification via gateway.
文摘以丙烯腈(AN)为单体,聚丙二醇双甲基丙烯酸酯(PPGDMA)为交联剂制备了丁二腈(SN)增塑的塑性PAN-co-PPGDMA交联聚合物-双三氟甲基磺酰亚胺锂(Li TFSI)复合电解质poly-SN40。研究表明,poly-SN40具有较宽的电化学窗口(0-5.2 V vs Li/Li^(+))和较高的室温离子电导率(1.27 mS/cm);组装的锂电池Li/ploy-SN40/LiFePO4的充放电实验表明,在0.5 m A/cm^(2)的电流密度下,电池能够正常、安全地循环使用;电池在0.2 C倍率下室温循环比容量超过133.5 m Ah/g,在200次循环后容量保持率为92%,表现出98.3%的优异平均库仑效率。
文摘针对舱内无线光传输系统多种干扰问题,比如多径损耗和突发干扰等,提出一种基于链路状态的自适应干扰消除技术,该方法分析舱内链路状态,完成链路状态估计,采用环境自适应的变遗忘因子RLS(recursive least squares)算法,针对不同链路状态采取差异化的干扰消除策略,以提高舱内通信质量。仿真结果表明:该算法在尽力避免增加算法复杂度的条件下,相对于传统固定遗忘因子算法,在平稳状态下优先保证传输的误码性能,在链路状态变化时具有更好的收敛性能,灵活适应了舱内多种传输情况。
基金funded by Research Supporting Project Number(RSPD2023R585),King Saud University,Riyadh,Saudi Arabia.
文摘The purpose of this article is to propose Stability-based Energy-Efficient Link-State Hybrid Routing(S-ELHR),a low latency routing proto-col that aims to provide a stable mechanism for routing in unmanned aerial vehicles(UAV).The S-ELHR protocol selects a number of network nodes to create a Connected Dominating Set(CDS)using a parameter known as the Stability Metric(SM).The SM considers the node’s energy usage,connectivity time,and node’s degree.Only the highest SM nodes are chosen to form CDS.Each node declares a Willingness to indicate that it is prepared to serve as a relay for its neighbors,by employing its own energy state.S-ELHR is a hybrid protocol that stores only partial topological information and routing tables on CDS nodes.Instead of relying on the routing information at each intermediary node,it uses source routing,in which a route is generated on-demand,and data packets contain the addresses of the nodes the packet will transit.A route recovery technique is additionally utilized,which first locates a new route to the destination before forwarding packets along it.Through simulation for various network sizes and mobility speeds,the efficiency of S-ELHR is shown.The findings demonstrate that S-ELHR performs better than Optimized Link State Routing(OLSR)and Energy Enhanced OLSR(EE-OLSR)in terms of packet delivery ratio,end-to-end delay,and energy consumption.
文摘The presence of aflatoxin-producing fungi in foods consumed by humans and animals has often resulted in the health hazards and even death. Aflatoxin contaminations of garri sold in some markets of Benue State, Nigeria, were studied, to ascertain the health implications on the consumers. Sixty garri samples comprising of 30 white garri and 30 yellow garri respectively were studied. The garri samples were ground to a particle size of 250 μm using a sterile blender. The total aflatoxin was extracted using 70% (v/v) methanol. The total aflatoxin concentration was detected and quantified using the Enzyme-Linked Immunosorbent Assay technique. The results showed that overall, 76.67% of the white garri samples and 80% of the yellow garri samples were aflatoxin positive. The total aflatoxin concentration in white garri ranged from 0.3 μg/kg to 2.4 μg/kg and 0.2 to 2.4 μg/kg in yellow garri respectively. The total mean aflatoxin across the States recorded was 2.96 μg/kg in white garri and 3.07 μg/kg in yellow garri. All the aflatoxin-positive garri samples of both the white and yellow garri were within the NAFDAC permissible aflatoxin level. Even though the aflatoxins are within the approved standard consumable limits, the continuous consumption of these doses over a long period of time could lead to the accumulation of these toxins in the body. These may eventually constitute a toxic health challenge.
文摘优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控制开销,浪费短波有限的带宽资源,导致网络通信性能急剧下降。其次,受到地形地貌、天线方向和接收性能的个体差异等影响,造成无线链路不稳定,导致网络中存在非对称链路,增加了通信端到端时延。为此,提出了一种低时延的短波自组网OLSR协议。该协议在执行MPR(Multipoint Relay)选择算法时综合考虑了节点的连接度和链路可靠性,在优化MPR节点个数的同时选择链路可靠性较大的节点作为MPR节点,在进行路由选择时能够利用网络中的非对称链路。仿真结果表明,该协议能优化数据包投递成功率、吞吐量、端到端时延和网络控制开销等性能指标。
文摘由于光网络中的路径跳数过多或距离偏大,使寻找可用的频谱资源难度增加,导致光网络动态频谱利用率降低、网络效益较少且阻塞率较高,为此,提出基于蛙跳博弈优化算法的光网络动态频谱分配方法。采用OHM(Optimized Link State Routing Protocol using the Highway Model)路由算法,选择与业务请求对应,且满足跳数最小、调制等级最高的候选路径,找到可用的频谱资源。根据获取的频谱资源,在光网络中将最大频隙号在所有链路中最小作为目标,构建光网络动态频谱分配的目标函数。并在约束条件下,采用蛙跳博弈优化算法对目标函数求解,获取的解即为光网络动态频谱分配最优结果。实验结果表明,该方法的阻塞率低、频谱利用率高、网络收益高,具有实用性。
文摘By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three-qubit states on the surface of a trivial torus. Thus, we obtain eight knotted pictures 121 linkage on the ordinary plane.
