面向内容的有限状态网络服务模型

 提出了一个新的基于有限状态机的网络服务模型,该模型以一种有限状态移动主体(FS-Agent)作为服务的基本单元,分别用服务内容状态机(Content-FS)和服务计算状态机(MACM-FS,即移动主体计算模型)来定义网络服务中的服务内容和服务计算过程,从而构建了一种面向内容的网络服务模型.实验结果表明,该网络服务模型具有良好的可扩展性和较高的网络服务效率.     

Emerging Wearable Sensors for Plant Health Monitoring

Emerging plant diseases, caused by pathogens, pests, and climate change, are critical threats to not only the natural ecosystem but also human life. To mitigate crop loss due to various biotic and abiotic stresses, new sensor technologies to monitor plant health, predict, and track plant diseases in real time are desired. Wearable electronics have recently been developed for human health monitoring. However, the application of wearable electronics to agriculture and plant science is in its infancy. Wearable technologies mean that the sensors will be directly placed on the surfaces of plant organs such as leaves and stems. The sensors are designed to detect the status of plant health by profiling various trait biomarkers and microenvironmental parameters, transducing bio-signals to electric readout for data analytics. In this perspective, the recent progress in wearable plant sensors is summarized and they are categorized by the functionality, namely plant growth sensors, physiology, and microclimate sensors, chemical sensors, and multifunctional sensors. The design and mechanism of each type of wearable sensors are discussed and their applications to address the current challenges of precision agriculture are highlighted. Finally, challenges and perspectives for the future development of wearable plant sensors are presented.     

Plasmonic Dual‐Enhancement and Precise Color Tuning of Gold Nanorod@SiO2 Coupled Core–Shell–Shell Upconversion Nanocrystals

The last decade has witnessed the remarkable research progress of lanthanide‐doped upconversion nanocrystals (UCNCs) at the forefront of promising applications. However, the future development and application of UCNCs are constrained greatly by their underlying shortcomings such as significant nonradiative processes, low quantum efficiency, and single emission colors. Here a hybrid plasmonic upconversion nanostructure consisting of a GNR@SiO₂ coupled with NaGdF₄:Yb³⁺,Nd³⁺@NaGdF₄:Yb³⁺,Er³⁺@NaGdF₄ core–shell–shell UCNCs is rationally designed and fabricated, which exhibits strongly enhanced UC fluorescence (up to 20 folds) and flexibly tunable UC colors. The experimental findings show that controlling the SiO₂ spacer thickness enables readily manipulating the intensity ratio of the Er³⁺ red, green, and blue emissions, thereby allowing us to achieve the emission color tuning from pale yellow to green upon excitation at 808 nm. Electrodynamic simulations reveal that the tunable UC colors are due to the interplay of plasmon‐mediated simultaneous excitation and emission enhancements in the Er³⁺ green emission yet only excitation enhancement in the blue and red emissions. The results not only provide an upfront experimental design for constructing hybrid plasmonic UC nanostructures with high efficiency and color tunability, but also deepen the understanding of the interaction mechanism between the Er³⁺ emissions and plasmon resonances in such complex hybrid nanostructure.     

基于LS-SVM的机载天线伺服机构自适应控制

针对机载天线伺服机构运行时所受外力是快时变、变化范围大、且自身摩擦等非线性特性不能忽略的问题,提出一种基于最小二乘支持向量机(LS-SVM)的自适应控制设计方法。此方法将摩擦等非线性特性视为未知项,并利用LS-SVM在线估计被控对象的非线性未知项,从而设计得到LS-SVM的学习规则。系统运行结果证明:该方法能够很好地解决全范围内的系统稳定问题,并能在线跟踪任何光滑的输入信号,同时补偿摩擦等非线性特性,改善系统的动态品质和静态特性。     

基于实时钟芯片的电子万年历的设计

电子万年历以AT89S52单片机为控制核心,采用Dallas公司的DS12C887A实时钟芯片构成计时电路,实现了时间和日期的显示,还增加了温度显示和整点报时的功能.文章对该系统的硬件电路、工作原理做了详细介绍,同时给出了软件设计的流程图及主要程序源代码.     

基于最短路径分割算法的SDH环网通路组织优化

针对SDH双向复用段保护环通路组织设计中存在的通路资源利用不充分及网络负载不平衡问题,本文提出一种基于最短路径分割的通路组织安排算法,该算法结合最短路径算法和平衡加载算法的优点,较好地满足了工程设计在经济性、安全性等方面的要求.本文最后实例中将该算法应用于SDH环网通路组织优化设计中,优化效果明显.     

硼酸-柠檬酸比色法测银杏枝叶中黄酮苷含量

用硼酸-柠檬酸比色法测定了银杏枝叶不同季节黄酮苷的含量,结果表明:硼酸-柠檬酸比色法测定银杏枝叶中的黄酮苷含量稳定性好,精度高,标准差为0.06,黄酮苷测定回收率为98.3%～101.1%,测定结果不受脂溶性杂质的干扰;银杏枝叶中的黄酮苷含量随季节的变化而变化,8月黄酮苷含量最高。     

DSP在捷联惯性制导技术中的应用

捷联惯性制导系统由于没有稳定的平台而需要通过大量的数学运算建立数学平台 ,因此制导对计算装置的性能要求很高。DSP芯片的出现为这种需要大量实时计算的制导系统提供了方便的应用方案。文中介绍了一种用DSP芯片设计的捷联惯性制导系统 ,给出了整个系统的电路和程序设计方法     

邮政国际速递邮件EDI电子报关方案浅谈

简要介绍了我国海关EDI电子报关的情况及邮政国际速递报关现状，提出了两个邮政国际速递EDI电子报关方案并加以分析、比较。     

气缸孔两种激光表面处理加工技术的比较

本文简要介绍了激光淬火技术和激光珩磨技术,并从耐磨延寿机理、主要技术要素、处理加工工艺以及应用 效能等方面对它们进行了比较研究,结果表明两者是不同的激光表面处理加工方法。