High Q×f values of Zn-Ni co-modified LiMg0.9Zn0.1-xNixPO4 microwave dielectric ceramics for 5G/6G LTCC modules

In this work, Zn-Ni co-modified LiMg_0.9Zn_0.1-xNi_xPO₄ (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 ε_r is mainly affected by the ionic polarizability, lattice and bond energy, while P-O bond plays a decisive role in Q×f and τ_f value. Optimum properties of Q×f ~ 153,500 GHz, ε_r ~ 7.13 and τ_f ~ ?59 ppm/°C were achieved for the composition LiMg_0.9Zn_0.06Ni_0.04PO₄ 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.     

基于CiteSpace的资源型产业研究知识图谱分析

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。     

TiO2/MXene-Assisted LDI-MS for Urine Metabolic Profiling in Urinary Disease

Cancer remains an intractable medical problem. Rapid diagnosis and identification of cancer are critical to differentiate it from nonmalignant diseases. High-throughput biofluid metabolic analysis has potential for cancer diagnosis. Nevertheless, the present metabolite analysis method does not meet the demand for high-throughput screening of diseases. Herein, a high-throughput, cost-effective, and noninvasive urine metabolic profiling method based on TiO₂/MXene-assisted laser desorption/ionization mass spectrometry (LDI-MS) is presented for the efficient screening of bladder cancer (BC) and nonmalignant urinary disease. Combined with machine learning, TiO₂/MXene-assisted LDI-MS enables high diagnostic accuracy (96.8%) for the classification of patient groups (including 47 BC and 46 ureteral calculus (UC) patients) from healthy controls (113 cases). In addition, BC patients can also be identified from noncancerous UC individuals with an accuracy of 88.3% in the independent test cohort. Furthermore, metabolite variations between BC and UC individuals are investigated based on relative quantification, and related pathways are also discussed. These results suggest that this method, based on urine metabolic patterns, provides a potential tool for rapidly distinguishing urinary diseases and it may pave the way for precision medicine.     

Structural characteristics and high-temperature oxidation behaviour of nano-HfO2-doped thermal barrier coatings

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.     

载铜树脂处理高含盐氨氮废水的性能

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。     

凹凸棒制备Si@C复合材料及其用于锂离子电池负极材料的电化学性能

硅因其超高的理论比容量而被视为最具潜力的下一代锂离子电池（LIBs）负极材料。目前，硅负极材料的高成本和极其苛刻的合成条件严重阻碍了其在LIBs中的使用。以天然凹凸棒为原料，通过水热法提纯和镁热还原反应制备了硅纳米颗粒（MRR Si），并进一步采用化学气相沉积法以乙炔为碳源制备了MRR Si@C复合材料，系统研究了其作为LIBs负极材料的储锂性能。研究结果表明:通过镁热还原制备的硅纳米在0.2 A/g的电流密度下可展现出2 362 mAh/g的比容量，首次库伦效率（CE）为71.87%，100次（0.5 A/g）循环充放电测试后比容量为909 mAh/g。相比之下，在MRR Si纳米颗粒表面沉积碳层后制备的MRR Si@C复合材料可展现出2 494 mAh/g的放电容量和78.92 %的高CE值。循环性能显示，该复合材料在0.5 A/g的电流密度下充/放电100次后的比容量值可达到1 324mAh/g。同时，该复合材料还可在5 A/g的大电流密度下依然可展现出高达844 mAh/g的高比容量。该MRR Si@C复合材料显示了优异的倍率性能和良好的应用前景。      

Impact of gas formation on the transfer of Ti and O from TiO2-bearing basic-fluoride fluxes to submerged arc welded metals: A thermodynamic approach

Gas-slag-metal equilibrium calculations are performed to investigate the transfer of Ti and O to submerged arc welded metals with increasing TiO₂ addition in basic-fluoride fluxes. The results indicate that activities of TiO₂ and Ti₂O₃ considering slag-metal reactions alone do not account for Ti transfer behaviors since TiF₃ gas tends to form and reduce Ti-oxide activities. Thermodynamic simulation indicates that consideration of gases is essential to improve the prediction accuracy of Ti and O concentrations.     

Cu-Ni合金腐蚀行为的宏观电化学研究进展

综述了Cu-Ni合金腐蚀行为的宏观电化学的国内外研究进展.介绍了合金成分、外界环境、腐蚀产物膜及初始表面膜等因素对Cu-Ni合金耐蚀性能的影响，详细介绍了合金元素通过影响腐蚀产物膜的组织结构从而影响腐蚀过程的各种理论，针对目前Cu-Ni合金腐蚀行为的研究不足作出了适当的分析并指出了今后的研究方向.      

基于模糊谱聚类的不确定蛋白质相互作用网络功能模块挖掘

针对谱聚类融合模糊C-means（FCM）聚类的蛋白质相互作用（PPI）网络功能模块挖掘方法准确率不高、执行效率较低和易受假阳性影响的问题，提出一种基于模糊谱聚类的不确定PPI网络功能模块挖掘（FSC-FM）方法。首先，构建一个不确定PPI网络模型，使用边聚集系数给每一条蛋白质交互作用赋予一个存在概率测度，克服假阳性对实验结果的影响；第二，利用基于边聚集系数流行距离（FEC）策略改进谱聚类中的相似度计算，解决谱聚类算法对尺度参数敏感的问题，进而利用谱聚类算法对不确定PPI网络数据进行预处理，降低数据的维数，提高聚类的准确率；第三，设计基于密度的概率中心选取策略（DPCS）解决模糊C-means算法对初始聚类中心和聚类数目敏感的问题，并对预处理后的PPI数据进行FCM聚类，提高聚类的执行效率以及灵敏度；最后，采用改进的边期望稠密度（EED）对挖掘出的蛋白质功能模块进行过滤。在酵母菌DIP数据集上运行各个算法可知，FSC-FM与基于不确定图模型的检测蛋白质复合物（DCU）算法相比，F-measure值提高了27.92%，执行效率提高了27.92%；与在动态蛋白质相互作用网络中识别复合物的方法（CDUN）、演化算法（EA）、医学基因或蛋白质预测算法（MGPPA）相比也有更高的F-measure值和执行效率。实验结果表明，在不确定PPI网络中，FSC-FM适合用于功能模块的挖掘。     

排污费改变了中国稀土出口吗? ——来自微观企业的证据

中国战略性矿产资源稀土开采和出口的同时带来了严重的环境污染.将稀土企业排污费强度作为环境规制指标引入异质性企业贸易模型，将工业企业数据库中的排污费数据与海关数据库中的贸易数据对接，研究了稀土企业排污费强度对出口的影响.研究发现:企业出口总金额与单位排污费强度指标均为负相关，在国内不存在“向底线赛跑”的现象，《排污费征收使用管理条例》是有效的；稀土企业出口数量随单位产值、单位规模排污费的增加呈先上升后下降趋势；产品质量与单位排污费强度指标均为负相关，其中单位产量、单位规模排污费与产品质量呈U型关系，产品质量随单位产量、单位规模排污费增加而下降且未到达拐点，在一定程度上支持了“波特假说”；提高企业全要素生产率虽然会降低出口总数量，却能提升稀土出口产品质量.总体而言，环境规制有助于降低中国稀土企业污染排放，提升稀土产品品质.