Preparation and characterization of carbon-encapsulated iron nanoparticles and their catalytic activity in the hydrogenation of levulinic acid

This study describes the synthesis of carbon-encapsulated iron nanoparticles using an ultrasonic method and also investigates their catalytic activity. These nanoparticles have been prepared using ultrasonic irradiation followed by annealing at various temperatures. As the annealing temperature of as-prepared α-Fe₂O₃ nanoparticles increased, the sample transformed into γ-Fe₂O₃, Fe₃O₄, and Fe nanoparticles via the reduction process without requiring any additional reducing agents such as H₂ gas, thus, creating a carbon shell surrounding the nanoparticles. By controlling the experimental conditions, Fe nanoparticles of various sizes can be formed with diameters in the range 100–800 nm; these nanoparticles are tightly encapsulated by 20-nm-thick carbon shells. Because of their high saturation magnetization 212 emu g^?1, the carbon-encapsulated Fe nanoparticles can be used for magnetic resonance imaging with a dramatically enhanced efficiency compared to commercially available T ₂ contrast agents. Moreover, the carbon-encapsulated Fe nanoparticles showed its superior catalytic activity and reusability for the hydrogenation of biomass-derived levulinic acid to GVL (99.6 %) in liquid phase.     

模拟深海采矿环境下混响的局部平稳性分析

针对深海采矿环境中强混响干扰下目标回波提取困难的问题,提出了海底强混响环境的模拟方法,在此基础上建立了采矿模拟环境中混响干扰的AR模型,并利用建立的AR模型计算了模拟环境中信号的Itakura距离.以建立的AR模型及Itakura距离为基础,建立了海底强混响仿真模型,对不同Itakura距离下的仿真信号及己知Itakura距离的大量实验数据分段预白化处理.仿真和实验数据处理结果表明模拟采矿环境下混响具有局部平稳性.     

A Feasibility Study on the Use of Near Infrared Spectroscopy for the Authentication of Depurated Salmon Fillets

Some species of actinomycetes, fungi, and blue-green algae produce semivolatile off-flavor compounds responsible for earthy-musty odorants in water from aquaculture facilities and tend to bioaccumulate within fish flesh. Although these off-flavor compounds are harmless to human health, high levels within fish tissue lead to an undesirable taste leading to an unmarketable consumption quality. Preharvest processes such as depuration can be used to eliminate most of these off-flavor compounds and ultimately enhance salmon quality. This study examined the potential of near infrared spectroscopy (NIRS) to discriminate depurated from nondepurated salmon fillets (n?=?62). Partial least squares discriminant analysis based on NIR spectra correctly classified 100 % of non-depurated and depurated salmon fillets. The successful classification was likely a consequence of statistically significant differences in the content of off-flavor compounds between both samples, which could have been detected by NIR spectra. Thus, NIRS is a fast, inexpensive, solvent-free, and non-destructive technology that can be used for the authentication of salmon with enhanced quality for marketing purposes.     

A Surface Tailoring Method of Ultrathin Polymer Gate Dielectrics for Organic Transistors: Improved Device Performance and the Thermal Stability Thereof

Tailoring the surface of the dielectric layer is of critical importance to form a good interface with the following channel layer for organic thin film transistors (OTFTs). Here, a simple surface treatment method is applied onto an ultrathin (<15 nm) organosilicon‐based dielectric layer via the initiated chemical vapor deposition (iCVD) to make it compatible with organic semiconductors without degrading its insulating property. A molecular‐thin oxide capping layer is formed on a 15 nm thick poly(1,3,5‐trimetyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3) by a brief oxygen plasma treatment. The capping layer greatly enhances the thermal stability of the dielectrics, without degrading the original mechanical flexibility and insulating performance of the dielectrics. Moreover, the surface silanol functionalities formed by the plasma treatment can also be utilized for the surface modification with silane compounds. The surface‐modified dielectrics are applied to fabricate low‐voltage operating (<5 V) pentacene‐based OTFTs. The highest field‐effect mobility of the device with the surface‐treated 15 nm thick pV3D3 is 0.59 cm² V^?1 s^?1, which is improved up to two times compared to the TFT with the pristine pV3D3. It is believed that the simple surface treatment method can widely extend the applicability of the highly robust, ultrathin, and flexible pV3D3 gate dielectrics to design the surface of the dielectrics to match well various kinds of organic semiconductors.     

基于IMM的舰载雷达目标跟踪算法研究

首先研究了目标跟踪中的卡尔曼滤波算法和常用的机动目标跟踪模型,分析了各模型基于卡尔曼滤波算法的跟踪性能。然后,引入交互式多模型算法,使用多个不同的运动模型匹配目标不同的运动模式,且各模型之间存在交互。在MATLAB中模拟舰载雷达的目标运动航迹,采用交互式多模型算法,通过对经典交互式模型（即一个CV模型和一个CA模型）的实验仿真,验证了在目标跟踪系统中交互式多模型算法的有效性。     

西宁市建设用地节约集约利用评价系统设计

西宁市建设用地节约集约利用评价系统是基于G1S与数据库技术,遵循城市建设用地节约集约利用评价相关标准、规范,为解决西宁市建设用地节约集约评价中评价数据管理、评价计算和成果管理等需求而设计并开发的。该评价系统创新性地将GIS与数据库技术应用到了城市建设用地节约集约利用评价中,使得用地信息、评价结果与图有机地结合到一起,不仅提高了评价的效率,而且直观地表现了评价的结果,同时有利于西宁市建立建设用地节约集约评价和监督的长效机制。