激光快速烧结合成HfW_2O_8及其特性的研究

采用激光烧结的方法快速合成HfW2O8陶瓷,X射线衍射(XRD)和拉曼光谱分析表明,合成物的主要成分是立方相的HfW2O8含有极少量的正交相,这是由于样品在凝固的过程中温度从熔池到周围环境迅速降低会产生较大的压应力,压应力约在0.6GPa左右。扫描电镜(SEM)观察表明,晶粒沿激光扫描的方向取向生长,形貌为柱状晶,排列错落有致,均匀致密,晶粒内少有气孔,尺寸在几10μm左右。     

Protel99SE制板Multisim8仿真电路

分析Multisim8和Protel99SE电子设计自动化（EDA）软件各自优势。提出一种将这两种软件相结合的电子电路设计方法。通过典型实例给出从Muhisim8电路仿真设计到Protel99SE印制电路板设计的基本流程．并验证该设计方法的有效性和实用性。     

烧结气氛对X8R陶瓷材料结构与性能的影响

研究了Yb/Mg受主离子协同掺杂对BaTiO3陶瓷材料分别在空气、还原性气氛中,以及热处理过后的结构与性能的影响。X-射线衍射(XRD)分析表明,还原性气氛烧结抑制了受主离子在BaTiO3中的固溶度,使材料出现第二相Yb2Ti2O7。差热扫描热分析(DSC)测量图谱表明,过量的Yb掺杂破坏了陶瓷的壳-芯结构。在不同的气氛烧结条件下,通过适当调整Yb/Mg掺杂量,可获得既适用于Pd/Ag内电极又适用于Ni内电极且满足在-55~ 150℃范围内,容量随温度的变化率满足±15%内(X8R)特性要求的多层陶瓷电容器(MLCC)介质材料。     

Performance improvement for recommender systems using ontology

Recommender systems have emerged in the e-commerce domain and have been developed to actively recommend appropriate items to online users. The use of recently developed hybrid recommendation systems has helped overcome the main drawbacks of Content-Based Filtering (CBF) and Collaborative Filtering (CF). In hybrid recommendation systems that combine CF and CBF, the CF part uses two methods, including memory- and model-based approaches. Both approaches have some advantages and disadvantages for item recommendation. Sparsity has been one of the main difficulties associated with these approaches, whereas recommendation with high accuracy has been one of the important advantages of the memory-based approach. However, this approach is not scalable for current recommendation systems as their databases include huge numbers of items and users. In contrast, the model-based approach generates recommendations with low accuracy but is scalable for large databases in e-commerce recommender systems. Accordingly, to address this problem and take advantage of both approaches, in this work, we propose a new hybrid recommendation method and evaluate it using a real-world dataset. The aim is to improve efficiency and accuracy by designing a heuristic hybrid recommender method that combines memory-based and model-based approaches. Specifically, we use ontology in the CF part and improve ontology structure by eliminating uniformity of edges of the hierarchical relation between concepts (IS-A relation) in item ontology in the CBF part. Ontology structure is considered for improving accuracy; according to this, a new method for measuring semantic similarity that is more accurate than the traditional methods is presented. This new method can enhance the accuracy of CF and CBF in our method. In addition, the number of searches required to find similar clusters and neighbor users of the target user is decreased significantly using ontology, enhanced clustering and the new proposed algorithm. We evaluate the proposed method using a real-world dataset. The experimental results show that our method is more scalable and accurate than the benchmark k-Nearest Neighbor (k-NN) and model-based recommendation methods.     

基于Infineon平台的波兰语智能输入法实现

为了在Infineon平台上实现波兰语的智能输入法,该课题采用了模块化的设计方案,通过封装接口与平台接口的整合,Infineon平台的特点,并结合Zi8输入法和波兰语字符的特点,在PC端进行模拟仿真,采用模拟发短信的方式,成功实现了波兰语的智能联想输入,并顺利通过上屏显示验证。这种输入法,避免了以往输入法多次按键输入带来的不便,大大减少了输入的次数,使用户在输入时更高效、快捷、准确地得到想要的字符及词组。     

基于MSP430单片机的超低功耗温度采集系统设计

针对工业生产过程中常需对温度进行实时监控的需求,本文介绍了一种便携式超低功耗的温度采集与实时显示的温度采集系统。为了使温度采集系统功耗达到最低,本设计选用了TI公司的超低功耗MSP430FG4618单片机作为主控芯片,并对整个系统进行了有效的电源管理,最后采用FYD12864C-1液晶显示器将采集到的温度实时显示出来。...     

基于μPS3234A实现通用多国语言的液晶显示

本文介绍一种基于可编程单片机外围芯片μPS3234A、内嵌GB2312国标字库,以UTF8码驱动的通用多国语言的液晶显示技术.     

K0．8 Fe1．7 SeS超导体内的畴区形貌及三维分布研究

本文利用高角环形暗场像（HAADF）和衍衬像研究了K0．8 Fe1．7 SeS超导样品的超导畴区形貌及三维分布。在[001]带轴下观察到两类形貌的超导畴区,一类畴区尺寸为1μm左右,另一类为由几十纳米大小的小畴区组成的阵列。选区电子衍射和电子能量损失谱结果表明母体区对应Fe空位有序,而超导畴区可能对应K空位有序。STEM-EDS元素Mapping表明超导畴区边缘处K元素含量较多,K0．8 Fe1．7 SeS超导样品中可能至少存在三个相,分别为：K空位有序超导相、畴区外部Fe空位有序基体相以及两种空位有序区的过渡相。在[100]带轴下观察到了超导畴区具有连通性,构建了K0．8 Fe1．7 SeS超导样品中超导畴区的三维分布图。     

Copper@ZIF-8 Core-Shell Nanowires for Reusable Antimicrobial Face Masks

SARS-CoV-2 and other respiratory viruses spread via aerosols generated by infected people. Face masks can limit transmission. However, widespread use of disposable masks consumes tremendous resources and generates waste. Here, a novel material for treating blown polypropylene filtration media used in medical-grade masks to impart antimicrobial activity is reported. To produce thin copper@ZIF-8 core-shell nanowires (Cu@ZIF-8 NWs), Cu NWs are stabilized using a pluronic F-127 block copolymer, followed by growth of ZIF-8 to obtain uniform core-shell structures. The Cu@ZIF-8 NWs are applied to filtration media by dip coating. Aerosol filtration efficiency decreases upon exposure to ethanol (solvent for dip-coating), but increases with addition of Cu@ZIF-8 NWs. Cu@ZIF-8 NWs shows enhanced antibacterial activity, compared to Cu NWs or ZIF-8 alone, against Streptococcus mutans and Escherichia coli. Antiviral activity against SARS-CoV-2 is assayed using virus-infected Vero E6 cells, demonstrating 55% inhibition of virus replication after 48 h by 1 µg of Cu@ZIF-8 NWs per well. Cu@ZIF-8 NWs’ cytotoxicity is tested against four cell lines, and their effect on inflammatory response in A549 cells is examined, demonstrating good biocompatibility. This low-cost, scalable synthesis and straightforward deposition of Cu@ZIF-8 NWs onto filter media has great potential to reduce disease transmission, resource consumption, and environmental impact of waste.     

Mechanism of negative capacitance in LEDs

In order to explain the phenomenon of negative capacitance（NC） in light emitting diodes LEDs, we present a new model based on local strong recombination in active region and firstly deduce the analytic expression of NO from continuity equation. The theoretical result indicates that the NC effect becomes stronger when the carrier recombination rate increases in a certain range,which is consistent with the experimental result. Accordingly,we confirm that the NO is caused by carrier recombination in active reaion instead of by other exterior factors.