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1.
Yuelong Ma Le Zhang Tianyuan Zhou Bingheng Sun Chen Hou Shunshun Yang Jin Huang Rui Wang Farida A. Selim Zhongying Wang Ming Li Hao Chen Yun Wang 《Journal of the European Ceramic Society》2021,41(4):2834-2846
Ce:Y3Al5O12 transparent ceramics (TCs) with appropriate emission light proportion and high thermal stability are significant to construct white light emitting diode devices with excellent chromaticity parameters. In this work, strategies of controlling crystal-field splitting around Ce3+ ion and doping orange-red emitting ion, were adopted to fabricate Ce:(Y,Tb)3(Al,Mn)5O12 TCs via vacuum sintering technique. Notably, 85.4 % of the room-temperature luminescence intensity of the TC was retained at 150 °C, and the color rendering index was as high as 79.8. Furthermore, a 12 nm red shift and a 16.2 % increase of full width at half maximum were achieved owing to the synergistic effects of Tb3+ and Mn2+ ions. By combining TCs with a 460 nm blue chip, a warm white light with a low correlated color temperature of 4155 K was acquired. Meanwhile, the action mechanism of Tb3+ ion and the energy transfer between Ce3+ and Mn2+ ions were verified in prepared TCs. 相似文献
2.
3.
Ming Zhang Xuefeng Jiang Qicheng Zhang Tao Zheng Mohsen Mohammadniaei Wentao Wang Jian Shen Yi Sun 《Advanced functional materials》2021,31(38):2102274
Immunotherapy is an efficient approach to clinical oncology. However, the immune privilege of the central nervous system (CNS) limits the application of immunotherapeutic strategies for brain cancers, especially glioblastoma (GBM). Tumor resistance to immune checkpoint inhibitors is a further challenge in immunotherapies. To overcome the immunological tolerance of brain tumors, a novel multifunctional nanoparticle (NP) for highly efficient synergetic immunotherapy is reported. The NP contains an anti-PDL1 antibody (aPDL1), upconverting NPs, and the photosensitizer 5-ALA; the surface of the NP is conjugated with the B1R kinin ligand to facilitate transport across the blood-tumor-barrier. Upon irradiation with a 980 nm laser, 5-ALA is transformed into protoporphyrin IX, generating reactive oxygen species. Photodynamic therapy (PDT) further promotes intratumoral infiltration of cytotoxic T lymphocytes and sensitizes tumors to PDL1 blockade therapy. It is demonstrated that combining PDT and aPDL1 can effectively suppress GBM growth in mouse models. The proposed NPs provide a novel and effective strategy for boosting anti-GBM photoimmunotherapy. 相似文献
4.
Optimization of room-temperature TCR of polycrystalline La0.9-xSrxK0.1MnO3 ceramics by Sr adjustment
Hongjiang Li Kaili Chu Xingrui Pu Xiaohan Yu Xiaoli Guan Shuaizhao Jin Xiang Liu 《Ceramics International》2021,47(1):94-101
High-density La0.9-xSrxK0.1MnO3 ceramics (LSKMO, A-site = La, Sr and K, 0 ≤ x ≤ 0.25) are successfully fabricated by using facile sol-gel method. Electrical properties are performed by using combination of phenomenological percolation (PP) model, double exchange (DE) mechanism, and Jahn-Teller (JT) effect. Moreover, X-ray diffraction and scanning electron microscopy are employed to analyze the structure and morphology of LSKMO ceramics. Valence states and ionic stoichiometry are assessed by using X-ray photoemission spectrometry. Results reveal that Sr2+ ions, substituting La3+ ions, significantly influenced DE mechanism and JT effect. In addition, Sr-doping plays essential role in improving electrical properties of LSKMO ceramics. At optimal doping content of x = 0.09, peak temperature coefficient of resistance (TCR) of the resistivity is found to be 11.56% K?1 at 297.15 K, which is optimal TCR for A-site K-occupied perovskite manganese oxides. These results confirm that polycrystalline LSKMO ceramics render high room-temperature TCR values due to Sr-doping. 相似文献
5.
Pu Mao Jiping Wang Peng Xiao Lixue Zhang Fang Kang Hao Gong 《Ceramics International》2021,47(1):111-120
In this work, we developed a novel system of isovalent Zr4+ and donor Nb5+ co-doped CaCu3Ti4O12 (CCTO) ceramics to enhance dielectric response. The influences of Zr4+ and Nb5+ co-substituting on the colossal dielectric response and relaxation behavior of the CCTO ceramics fabricated by a conventional solid-phase synthesis method were investigated methodically. Co-doping of Zr4+ and Nb5+ ions leads to a significant reduction in grain size for the CCTO ceramics sintered at 1060 °C for 10 h. XRD and Raman results of the CaCu3Ti3.8-xZrxNb0.2O12 (CCTZNO) ceramics show a cubic perovskite structure with space group Im-3. The first principle calculation result exhibits a better thermodynamic stability of the CCTO structure co-doped with Zr4+ and Nb5+ ions than that of single-doped with Zr4+ or Nb5+ ion. Interestingly, the CCTZNO ceramics exhibit greatly improved dielectric constant (~105) at a frequency range of 102–105 Hz and at a temperature range of 20–210 °C, indicating a giant dielectric response within broader frequency and temperature ranges. The dielectric properties of CCTZNO ceramics were analyzed from the viewpoints of defect-dipole effect and internal barrier layer capacitance (IBLC) model. Accordingly, the immensely enhanced dielectric response is primarily ascribed to the complex defect dipoles associated with oxygen vacancies by co-doping Zr4+ and Nb5+ ions into CCTO structure. In addition, the obvious dielectric relaxation behavior has been found in CCTZNO ceramics, and the relaxation process in middle frequency regions is attributed to the grain boundary response confirmed by complex impedance spectroscopy and electric modulus. 相似文献
6.
Hao Chen Jie Xing Jingwen Xi Tao Pu Hong Liu Jianguo Zhu 《Journal of the American Ceramic Society》2021,104(12):6266-6276
The Ag-Pd internal electrode of multilayer piezoelectric ceramics needs to be sintered below 1000°C, and lead wires and components need to be welded with lead-free solder at 260°C. PNN–PMW–PZT–xSr piezoelectric ceramics with high Curie temperature (Tc > 260°C) were synthesized at a low sintering temperature (960°C) to meet the requirements of multilayer piezoelectric devices. The relationship between structures (phase, domain, and microstructures) and electrical properties (piezo/ferroelectric properties, and dielectric relaxation) in the Sr2+ substituted ceramics was investigated. Rietveld refinement and Raman spectra show that Sr2+ substitution can cause the phase change and increase the force constant of [BO6] octahedron. The piezoelectric response increases with increasing the content of the tetragonal phase (CTP) in the rhombohedral-tetragonal (R-T) coexisted ceramics. The ceramics with 0.6 mol% Sr2+ substitution have minimum activation energy for domain wall movement (Ea) of 0.0362 eV which favors the formation of nanometer-sized domains, and possess excellent electrical properties (d33 = 623 pC/N, d33* =783 pm/V, Tc =295°C). The higher the CTP, the lower the Ea. The lower Ea favors the rotation of polarization direction and extension, and is beneficial to the generation of the nanometer-size domains, resulting in high piezoelectric properties. 相似文献
7.
Glass-based materials are usually considered as excellent seals for jointing adjacent components in planar solid oxide fuel cells, but the uncontrollable crystallization in the glass may cause delamination and micro-cracks in such seals. To solve this problem, Al2O3 ceramic particles were added to a BaO–CaO–Al2O3–B2O3–SiO2 glass system to reduce negative effects caused by crystalline phase on the gas tightness and the joint strength in the seals. At an operating temperature of 750 °C, the glass-based seals with 20 wt% Al2O3 addition (GA80) exhibited extremely low leakage rates (~0.002 sccm/cm under an input gas pressure of 13.6 kPa) and higher shear strength (3.31 MPa). The Al2O3 ceramic addition and the crystalline phase BaAl2Si2O8 reinforced the glass matrix. Further thermal cycle analyses indicated that leakage rates for the GA80 seals remained at around 0.0025 sccm/cm after 10 thermal cycles, which was consistent with minor microstructural change and good interface bonding. Single cell testing with of GA80 seals was performed and the results demonstrated stable electrochemical performance through 6 thermal cycles at an open circuit voltage of 1.16–1.18 V, as well as a power density above 546 mW/cm2 at a current density of 925 mA/cm2. These results showed the high thermal cycle stability of the glass/Al2O3 composite seals in intermediate temperature planar solid oxide fuel cells. 相似文献
8.
Yueqiang LI Chao GAO Bin WU Yushuai WANG Haibo ZHENG Ming XUE Yuling WANG 《等离子体科学和技术》2021,23(2):25501-37
The turbulent boundary layer control on NACA 0012 airfoil with Mach number ranging from 0.3 to 0.5 by a spanwise array of dielectric barrier discharge(DBD)plasma actuators by hot-film sensor technology is investigated.Due to temperature change mainly caused through heat produced along with plasma will lead to measurement error of shear stress measured by hot-film sensor,the correction method that takes account of the change measured by another sensor is used and works well.In order to achieve the value of shear stress change,we combine computational fluid dynamics computation with experiment to calibrate the hot-film sensor.To test the stability of the hot-film sensor,seven repeated measurements of shear stress at Ma = 0.3 are conducted and show that confidence interval of hot-film sensor measurement is from-0.18 to 0.18 Pa and the root mean square is 0.11 Pa giving a relative error 0.5%over all Mach numbers in this experiment.The research on the turbulent boundary layer control with DBD plasma actuators demonstrates that the control makes shear stress increase by about 6%over the three Mach numbers,which is thought to be reliable through comparing it with the relative error 0.5%,and the value is hardly affected by burst frequency and excitation voltage. 相似文献
9.
Shuhai Liu Ming Han Xiaolong Feng Qiuhong Yu Long Gu Longfei Wang Yong Qin Zhong Lin Wang 《Advanced functional materials》2021,31(17):2010339
Utilizing inner-crystal piezoelectric polarization charges to control carrier transport across a metal-semiconductor or semiconductor–semiconductor interface, piezotronic effect has great potential applications in smart micro/nano-electromechanical system (MEMS/NEMS), human-machine interfacing, and nanorobotics. However, current research on piezotronics has mainly focused on systems with only one or rather limited interfaces. Here, the statistical piezotronic effect is reported in ZnO bulk composited of nanoplatelets, of which the strain/stress-induced piezo-potential at the crystals’ interfaces can effectively gate the electrical transport of ZnO bulk. It is a statistical phenomenon of piezotronic modification of large numbers of interfaces, and the crystal orientation of inner ZnO nanoplatelets strongly influence the transport property of ZnO bulk. With optimum preferred orientation of ZnO nanoplatelets, the bulk exhibits an increased conductivity with decreasing stress at a high pressure range of 200–400 MPa, which has not been observed previously in bulk. A maximum sensitivity of 1.149 µS m−1 MPa−1 and a corresponding gauge factor of 467–589 have been achieved. As a statistical phenomenon of many piezotronic interfaces modulation, the proposed statistical piezotronic effect extends the connotation of piezotronics and promotes its practical applications in intelligent sensing. 相似文献
10.
Wan-Li Tan Dr. Chun Zhang Yang Li Dr. Kai Guo Dr. Xiao-Wei Gao Dr. Jun Wei Dr. Dong Yi Prof. Lin Pu Prof. Dr. Qin Wang 《ChemMedChem》2021,16(23):3569-3575
Forty samples of optically active falcarindiol analogues are synthesized by using the easily available C2 symmetric (R)- and (S)-1,1’-binaphth-2-ol (BINOL) in combination with Ti(OiPr)4, Zn powder and EtI. Their anticancer activities on Hccc-9810, HepG2, MDA-MB-231, Hela, MG-63 and H460 cells are assayed to elucidate their structure-activity relationships. These results showed that the falcarindiol analogue (3R,8S)- 2 i with the terminal double bond has the most potent anti-proliferation effect on Hccc-9810 cells with IC50 value of 0.46 μM. The falcarindiol analogue (3R,8S)- 2 i can induce obvious Hccc-9810 cell apoptosis in a concentration-dependent manner by Hoechst staining and flow cytometry analysis. The proposed mechanism suggests that the falcarindiol analogue (3R,8S)- 2 i increases LDH release and MDA content, and reduces the levels of SOD activity, which lead to the accumulation of oxidative stress and induce apoptosis in Hccc-9810 cells. 相似文献