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1.
In this work, Zn-Ni co-modified LiMg0.9Zn0.1-xNixPO4 (x = 0–0.1) microwave dielectric ceramics were fabricated using a solid state synthesis route. Rietveld refinement of the XRD data revealed that all ceramic samples have formed a single phase with olivine structure. SEM images showed that the samples have a dense microstructure, that agrees with the measured relative density of 97.73 %. Based on the complex chemical bond theory, Raman and infrared reflectance spectra, we postulate that εr is mainly affected by the ionic polarizability, lattice and bond energy, while P-O bond plays a decisive role in Q×f and τf value. Optimum properties of Q×f ~ 153,500 GHz, εr ~ 7.13 and τf ~ ?59 ppm/°C were achieved for the composition LiMg0.9Zn0.06Ni0.04PO4 sintered at 875 ℃ for 2 h. This set of properties makes these ceramics an excellent candidate for LTCC, wave-guide filters and antennas for 5 G/6 G communication applications.  相似文献   
2.
资源型产业发展为推进国家经济增长和工业化进程提供了重要保障。为深入了解资源型产业的研究情况,以CNKI数据库为数据源,搜集2000—2020年关于资源型产业的核心及以上期刊论文,利用CiteSpace软件从发文作者与研究机构分布、关键词共现网络和时区图谱等方面,绘制知识图谱,进行可视化分析。研究发现:资源型产业领域的研究成果愈加丰富,但研究群体间联系合作较少,且现有的合作研究主要集中在所处地域资源富集和具有学科优势的研究机构及学者;资源型产业领域的研究热点可概括为产业发展、资源型城市、产业集群、产业结构、产业链和产业集聚等方面;针对资源型产业领域未来可从资源型产业相关理论研究、创新发展模式和可持续发展等方面深入展开。  相似文献   
3.
Jingdezhen is famous for its bluish white (Qingbai) porcelains of the Song Dynasty, and those decorated with iron spots are distinctive among them. Herein, iron spots on a bluish white porcelain were investigated using a series of microscopic and spectroscopic characterizations. We found the decreasing iron content from more than 8 wt% to about 2 wt% during the glaze color transition from rusty to brown and finally into green, which built a connection on the coloring mechanism of iron-rich crystallized glaze and celadon glaze. We identified the rare ε-Fe2O3, a promising magnetic material, in both the dark brown crystals and the triangular crystals in the rusty area, which is its first discovery among bluish white porcelains. Based on these findings, we discussed the coloring mechanism of iron-spot decoration along with the physical form of the iron oxide crystals, indicating the partially reducing atmosphere during firing process.  相似文献   
4.
Everything you need to know about e-commerce. The term "e-commerce" refers to any commercial transaction type that requires the transmission of information over the Internet. By definition, it uses the Internet as a platform for communication and financial transactions or, at the same time, covering various business activities. In the previous method based on Deep learning and .net for Collaborative Innovation of E-Commerce platform. In the existing method, perception of security and reliability and data integrity and protection are drawbacks of the previous method. The proposed FPGA (Field-programmable gate array) and Convolutional Neural Network (CNN) are used to develop the Collaborative Innovation of E-Commerce platform and easily interface with the network without any complexity. E-commerce is an Internet-based tool, usually the exchange of Internet-based products and services. E-commerce refers to commercial transactions and commercial transactions involving exchange (e.g., money) within organizational or personal boundaries. The Web exchanges cross-organizational or personal boundary value (such as gold) for products and services for commercial transactions and commercial transactions. Here focus effectively on trade between digital companies and individuals.  相似文献   
5.
In this work, doctors can find useful tips to discover semantic similarities to diagnostic tasks, natural biomedical language, and writing to obtain effective simulations. It proposes a concrete analytical framework for a considerable collection. It does some preliminary analysis using datasets extracted from the entire graduate entrance exam library. It has developed a web front end to demonstrate this method's practicality in the real-world context. The quickly extending field of enormous information examination is starting to assume a basic function in creating clinical practice and exploration. It gives a device to amass and retain a lot of organized and unstructured information created by the board, investigation, and current medical services frameworks. As of late, big data information examination has been applied to measures that help clinical administrations and illness investigation. The appropriation and R and D in this space are hampered by some key issues intrinsic in the huge information worldview. Basic Analysis of Images, Signals, and Genomics: In this article focus on these key challenges and discusses some of the three promising medical research areas. It targets large amounts of medical data, and the use of multimodal data from different sources has also been discussed in recent studies. Research Areas with the potential and significant impact in providing medical services are also being considered.  相似文献   
6.
This editorial paper provides an overview of new advances on hardware security challenges and promising solutions for real world applications. It first presents the increasing hardware vulnerabilities with the emergence of diverse computing platforms. Then, it details the technical challenges, research opportunities, and potential solutions to cyber-attacks on -physical- devices.  相似文献   
7.
A cheap and commercially available small molecule (namely EPPDI) is introduced to the active layer of N2200-based all polymer solar cells as a solid additive. EPPDI at the optimal ratio can improve the D-A nano-scale morphology and reduce trap density of the active layer by filling morphological spaces. As a result, the photovoltaic performance of the resulting devices based on PF2:N2200 are increased from 6.28% to 7.03% with significantly enhanced fill factor. This work demonstrates a facile approach for improving the performance of all polymer solar cells.  相似文献   
8.
《Ceramics International》2022,48(4):5229-5238
The uneven growth of thermally grown oxides (TGOs) in thermal barrier coating systems is an important cause of cracking failure at the coating interface in high-temperature environments. The doping of rare earth elements in the bonding layer can effectively inhibit the formation of spinel oxides in the TGO and improve the high-temperature oxidation resistance of the coating. However, a single rare earth element has a limited effect on inhibiting TGO failure. In this study, a NiCoCrAlYHf coating was prepared using a supersonic flame spraying (HVOF) technique. The effects of HfO2 doping on the high-temperature oxidation behaviour of the coatings and diffusion behaviour of metallic elements in the coatings were investigated at 1100 °C. The results showed that the nano-sized HfO2 filled the pores between the powder particles and improved the hardness of the coating. During the high-temperature oxidation process, the oxides formed by Hf and Y had a large size and low solubility, which effectively blocked the diffusion of Al. This slowed the generation of spinel oxides, effectively inhibited the growth of the TGO, it inhibits the initiation and propagation of cracks within the coating, reduces damage to the coating from tensile and compressive stresses at the interface, and improved the high-temperature oxidation resistance of the coating.  相似文献   
9.
针对高含盐氨氮废水,选择具有不同功能基团的树脂为载体,进行负载Cu2+改性制得载铜树脂并对其处理高含盐氨氮废水的性能进行研究。在筛选出最佳载铜树脂的基础上,研究pH及Na+浓度、树脂投加量、反应时间对载铜树脂处理高含盐氨氮废水效果的影响,通过对吸附氨氮前后的载铜树脂进行SEM和EDS表征分析并构建吸附动力学模型以进一步探究配位吸附的过程。结果表明,Cu2+可与螯合树脂D751稳定结合且在宽pH值下均表现出耐盐性和良好的氨氮吸附效果;在室温(25℃)、pH=11及Na+浓度4 g/L、树脂投加量8 g/L、反应时间60 min的条件下,D751载铜树脂对氨氮的去除率为34.8%。D751载铜树脂吸附氨氮后其表面出现明显的晶状结构物质,该物质可能为铜氨络合物。D751载铜树脂对高含盐氨氮的吸附符合准二级动力学模型。  相似文献   
10.
Video transmission over IEEE 802.11e wireless networks still shows poor performance for large bandwidth demand and frequently changed environments. Thus, several enhancements of IEEE 802.11e were proposed. On the other hand, big frames and simultaneous sending of adjacent frames always cause packet dropping for buffer overflow. In the past, we proposed an IEEE 802.11e enhancement named DFAA and a content aware mechanism to solve the above problems. The motivation of this paper is to find a proper way to integrate these two mechanisms. A DFAA enhancement (DFAA-E) is proposed to make up the insufficiency of content aware mechanism. Experiments results show that the combination of DFAA-E and content aware mechanism improves the video decoded quality greatly. And its performance can be further enhanced by selecting the suitable settings of certain parameters.  相似文献   
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