Antibacterial and photocatalytic behaviour of green synthesis of Zn0.95Ag0.05O nanoparticles using herbal medicine extract

The present work aimed to synthesize Zn_0.95Ag_0.05O (ZnAgO) nanoparticles using rosemary leaf extracts as a green chemistry method. The characterization of Ag-doped ZnO nanoparticles was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectrophotometry (UV–visible). The XRD, FTIR, and UV–visible spectra confirmed the formation of the presence of hexagonal ZnAgO nanoparticles. FESEM micrograph shows that the nanoparticles have been distributed homogeneously and uniformly. The morphology of ZnAgO nanoparticles is quasi-spherical configuration. Also, the mean particle size is in the range of 22–40 nm. The photocatalytic degradation of methylene blue in the presence of Ag-doped ZnO nanoparticles is nearly 98.5% after exposing 100 min. The ultraviolet lamp was used as the light source for photocatalyst degradation. The disc diffusion method was chosen to study the antibacterial activity of as-synthesized ZnAgO nanoparticles. Antibacterial activity of Zn_0.95Ag_0.05O nanoparticles against Staphylococcus aureus and Escherichia coli revealed that the as-synthesized ZnAgO nanoparticles were efficient in inhibition of bacterial growth.     

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.     

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.     

Preparation of a CeO2–ZrO2 based nano-composite with enhanced thermal stability by a novel chelating precipitation method

In this study, a chelating agent is introduced to prepare CeO₂–ZrO₂ nano-composite through a precipitation process. The physicochemical properties of the oxide precursors, nano composite materials are strongly dependent on the preparation method and whether a chelating agent is used. Adding an appropriate quantity of chelating agent SO₄²⁻ can facilitate thermal stability and phase structure uniformity of CeO₂–ZrO₂ mixed oxides. The calculation results showed that the Gibbs free energy of chelating complex of [ZrSO₄]²⁺ (ΔG = −127.2469 kJ/mol) is higher than the [Ce(III)SO₄]⁺ (ΔG = -29.8279 kJ/mol). The precipitation chemical potential of Zr⁴⁺ moves close to the precipitation chemical potential of Ce³⁺. The novel and low-cost chelating precipitation method can modify the homogeneity of the compounds at the atomic scale, which can offer a powerful opportunity for, and provide direction in, the design of materials with exceptional properties.     

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.     

供需协同下江西省钨产业结构调整与升级对策

钨矿是我国24种战略性矿产资源之一，也是“世界钨都”江西省的优势矿产资源之一，在工业生产和国民经济中具有重要地位.江西省钨产业在资源储量、产品产量、冶炼技术、企业经营等领域都位居全国前列，甚至领先全球.但是对比全球钨产业市场需求和趋势来看，江西省钨产业供给侧存在资源开采消耗速度较快、冶炼和低端加工产能过剩、高端深加工研发能力较弱、产业整体集中程度较低等与需求侧不相适应的问题，供需格局有待调整.文中在“供给侧改革”视角下，从采选、冶炼、加工、产业规制等方面提出了健全钨资源开发与保护的体制机制、加强钨产业市场监管、建立钨产业深加工科研激励体系、加快钨产业集群优化升级等政策建议，以使江西省钨产业供给侧适应需求侧发展，实现产业结构的优化升级，进一步提升江西钨产业竞争力、打造江西钨品牌，繁荣江西矿业经济.      

P2型锰基钠离子正极材料的制备与改性

实验以碳酸钠为钠源，采用溶胶-凝胶法分别合成钠离子正极材料Na_0.46Ni_0.26Mn_0.54O₂ 和含有部分铁离子的正极材料Na_0.46Ni_0.13Fe_0.13Mn_0.54O₂.两者均在相同的条件和相同煅烧温度下合成.分别讨论这两种材料结构上的差异和性能上的变化.利用X射线衍射仪观察两种材料的晶体结构、扫描电子显微镜观察两种材料的组织形貌.将合成的材料做成电池，分别进行电化学的测试.结果表明:不添加Fe元素的材料，即S1:Na_0.46Ni_0.26Mn_0.54O₂具有层状结构，呈现P2结构、形貌呈现为片束形状态，粒径大小均匀，且电池的电化学性能更佳.而添加了铁元素的材料即S2:Na_0.46Ni_0.13Fe_0.13Mn_0.54O₂，无论从结构、形貌和电化学性能来比较，都次于P2型结构的Na_0.46Ni_0.26Mn_0.54O₂.      

TbCu7型SmCo7-xHfx合金的结构及磁性能

采用熔体快淬法在40 m/s制备了SmCo_7-xHf_x （x=0, 0.1, 0.15, 0.2, 0.3）合金薄带，研究Hf取代量对SmCo_7-xHf_x合金的相组成、组织结构及磁性能的影响.结果表明:随Hf取代量的增加，均可获得TbCu₇型结构的亚稳相，晶格常数a和c也随之增加，c/a比值在0.82~0.83，晶粒平均尺寸减小，且更加均匀；在性能方面，Hf取代量为0.2时，可获得最优磁性能B_r为0.55 T和H_c为1 084 kA/m. Hf的添加还可有效改善合金高温性能，在27~400 ℃温度区间，矫顽力温度系数由未添加时-0.21 %/℃改善到-0.18 %/℃，提升14.3%.      

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.