Designing novel lubricants with easily customized structures,devisable compositions,and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications,prolonging machine lifet...Designing novel lubricants with easily customized structures,devisable compositions,and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications,prolonging machine lifetime,and saving energy.Deep eutectic solvents(DESs),which show tunable composition,adjustable structure,easy fabrication,and environmental friendliness,are promising candidates for variable and complicated lubricants applications.To promote the use of DESs as lubricants,a series of PEG200-based DESs with active heteroatoms were fabricated to tailor the tribological performance via tribo-chemistry.Thereinto,PEG200/boric acid(BA)DES shows optimal lubrication performance by forming tribo-chemical reaction film composited of B2O3,iron oxides,and FeOOH,and PEG200/thiourea(TU)DES displays abrasive wear-reducing property by producing FeS tribo-chemical film.Given the excellent abrasive wear-resistance of PEG200/TU DES and friction reduction of PEG200/BA DES,ternary PEG200/BA/TU DESs,composited of PEG200/TU DES and PEG200/BA DES,are first exploited.The ternary DESs possess superior wettability and thermal stability,which render them potential lubricants.Tribological tests of the ternary DESs demonstrate that synergistic lubrication is achieved by forming a transfer film consisting of FexBy,BN,B2O3,and FeS.Wherein FexBy,BN,and B2O3 increase load bearing of the film,and FeS mitigates severe abrasive wear.The proposed design philosophy of novel DESs as lubricants opens up a unique realm that is unattainable by traditional DESs lubrication mechanisms and provides a platform to design next-generation DESs lubrication systems.展开更多
以葡萄糖为碳源,聚乙二醇-200（PEG-200）为分散剂和表面修饰剂,采用水热法制备了具有良好水溶性的荧光碳点（CDs）。以CDs为荧光探针,在p H 5.72的Britton-Robinson（B-R）缓冲溶液中,镍离子可使CDs的荧光显著猝灭,据此建立了一种测定...以葡萄糖为碳源,聚乙二醇-200（PEG-200）为分散剂和表面修饰剂,采用水热法制备了具有良好水溶性的荧光碳点（CDs）。以CDs为荧光探针,在p H 5.72的Britton-Robinson（B-R）缓冲溶液中,镍离子可使CDs的荧光显著猝灭,据此建立了一种测定镍离子的荧光光度新方法。结果表明,体系的最大激发波长为350 nm,最大发射波长为435 nm;在最佳实验条件下,镍离子浓度在3.0~80μmol/L范围内与CDs的相对荧光强度呈良好的线性关系,其线性回归方程为ΔF=1.009＋0.031 0 c（μmol/L）,相关系数（r）为0.998 3,检出限为0.13μmol/L。方法应用于环境水样中痕量镍的测定,测定结果与原子吸收光谱法相符。该方法的加标回收率为98.1%~103.5%,相对标准偏差（RSD）小于2%。展开更多
Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol (PEG200) and Cu(NO3)2 as precursors are presented. It was found that PEG200 and sucrose were novel...Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol (PEG200) and Cu(NO3)2 as precursors are presented. It was found that PEG200 and sucrose were novel chelates and Cu (NO3)2 was an alternative precursor for the preparation of YBCO superconducting film by chemical solution route. The precursor solution was prepared by mixing yttrium trifluoroacetate, barium trifluoroacetate, and copper nitrate in solvent of methanol with chelates including PEG200 and sucrose. YBCO films were prepared by coating the precursor solution on LaAlO3 single crystal substrate, following vacuum drying, rapid calcining, firing and oxygen annealing. The prepared films were characterized by optical microscope (OM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that films were crack-free and homogeneous, stronger tendency of (00l) texture, uniform with less pore, pure c-axis orientation. The films showed good superconducting properties, with Tc of 90 K and critical current density (Jc) of 1 MA/cm2 (77 K, 0 T). This work demonstrates that the developed method is a promising method for preparation of YBCO superconducting film which has a fine superconducting characterization with advantages of simple and rapid.展开更多
Nickel hydroxide, Ni（OH）2 is widely used in electrodes of nickel-based alkaline secondary batteries, Ultrathin hexagonal Ni（OH）2 nanosheets of space group P-3ml were hydrothermally prepared at 200℃ for 10h. Their...Nickel hydroxide, Ni（OH）2 is widely used in electrodes of nickel-based alkaline secondary batteries, Ultrathin hexagonal Ni（OH）2 nanosheets of space group P-3ml were hydrothermally prepared at 200℃ for 10h. Their diameter and thickness were 200-300 and 3-5 nm, respectively, Their formation was attributed to the oriented assembly of growing particles, which was assisted by surfactant molecules. The specific surface area of the Ni（OH）2 nanosheets was 8.66 m2/g. Their magnetization curve exhibited linear paramagnetic behavior across the entire measurement region.展开更多
基金support from the National Natural Science Foundation of China(Nos.52175190 and 51805455)and the Fundamental Research Funds for the Central Universities(No.2682021CX117).
文摘Designing novel lubricants with easily customized structures,devisable compositions,and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications,prolonging machine lifetime,and saving energy.Deep eutectic solvents(DESs),which show tunable composition,adjustable structure,easy fabrication,and environmental friendliness,are promising candidates for variable and complicated lubricants applications.To promote the use of DESs as lubricants,a series of PEG200-based DESs with active heteroatoms were fabricated to tailor the tribological performance via tribo-chemistry.Thereinto,PEG200/boric acid(BA)DES shows optimal lubrication performance by forming tribo-chemical reaction film composited of B2O3,iron oxides,and FeOOH,and PEG200/thiourea(TU)DES displays abrasive wear-reducing property by producing FeS tribo-chemical film.Given the excellent abrasive wear-resistance of PEG200/TU DES and friction reduction of PEG200/BA DES,ternary PEG200/BA/TU DESs,composited of PEG200/TU DES and PEG200/BA DES,are first exploited.The ternary DESs possess superior wettability and thermal stability,which render them potential lubricants.Tribological tests of the ternary DESs demonstrate that synergistic lubrication is achieved by forming a transfer film consisting of FexBy,BN,B2O3,and FeS.Wherein FexBy,BN,and B2O3 increase load bearing of the film,and FeS mitigates severe abrasive wear.The proposed design philosophy of novel DESs as lubricants opens up a unique realm that is unattainable by traditional DESs lubrication mechanisms and provides a platform to design next-generation DESs lubrication systems.
基金National High Technology Research and Development Program of China ("863" Program) (2009AA03Z203)
文摘Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol (PEG200) and Cu(NO3)2 as precursors are presented. It was found that PEG200 and sucrose were novel chelates and Cu (NO3)2 was an alternative precursor for the preparation of YBCO superconducting film by chemical solution route. The precursor solution was prepared by mixing yttrium trifluoroacetate, barium trifluoroacetate, and copper nitrate in solvent of methanol with chelates including PEG200 and sucrose. YBCO films were prepared by coating the precursor solution on LaAlO3 single crystal substrate, following vacuum drying, rapid calcining, firing and oxygen annealing. The prepared films were characterized by optical microscope (OM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that films were crack-free and homogeneous, stronger tendency of (00l) texture, uniform with less pore, pure c-axis orientation. The films showed good superconducting properties, with Tc of 90 K and critical current density (Jc) of 1 MA/cm2 (77 K, 0 T). This work demonstrates that the developed method is a promising method for preparation of YBCO superconducting film which has a fine superconducting characterization with advantages of simple and rapid.
基金financial support from the National Innovation Engineering Program for new Energy Vehicle Industry Technology, National Natural Science Foundation of China(No.81225010)863 High-Tech Project of China(2012AA022603)
文摘Nickel hydroxide, Ni（OH）2 is widely used in electrodes of nickel-based alkaline secondary batteries, Ultrathin hexagonal Ni（OH）2 nanosheets of space group P-3ml were hydrothermally prepared at 200℃ for 10h. Their diameter and thickness were 200-300 and 3-5 nm, respectively, Their formation was attributed to the oriented assembly of growing particles, which was assisted by surfactant molecules. The specific surface area of the Ni（OH）2 nanosheets was 8.66 m2/g. Their magnetization curve exhibited linear paramagnetic behavior across the entire measurement region.
