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排序方式: 共有130条查询结果,搜索用时 312 毫秒
1.
Synthesis of ultrafine LiCoO2 powders by the sol-gel method 总被引:8,自引:0,他引:8
Ultrafine high-temperature (HT) LiCoO2 powders were synthesized by the sol-gel method using polyacrylic acid (PAA) as a chelating agent. The decomposition process of the gel precursor was examined to determine the crystallization temperature and the dependence of the physicochemical properties of HT-LiCoO2 powders on the PAA quantity was extensively investigated. Polycrystalline HT-LiCoO2 powders, composed of very uniformly sized ultrafine particulates with an average particle size of 30–50 nm and a specific surface area of 2.3–17 m2g–1, could be obtained at the lower calcination temperature of 550 °C and the shorter calcination time of 1 h compared to the solid-state reaction. 相似文献
2.
Arun Pandian Chandrasekaran Sang Hyeon Woo Neha Sarodaya Byung Ho Rhie Apoorvi Tyagi Soumyadip Das Bharathi Suresh Na Re Ko Seung Jun Oh Kye-Seong Kim Suresh Ramakrishna 《International journal of molecular sciences》2021,22(11)
Cell division cycle 25A (Cdc25A) is a dual-specificity phosphatase that is overexpressed in several cancer cells and promotes tumorigenesis. In normal cells, Cdc25A expression is regulated tightly, but the changes in expression patterns in cancer cells that lead to tumorigenesis are unknown. In this study, we showed that ubiquitin-specific protease 29 (USP29) stabilized Cdc25A protein expression in cancer cell lines by protecting it from ubiquitin-mediated proteasomal degradation. The presence of USP29 effectively blocked polyubiquitination of Cdc25A and extended its half-life. CRISPR-Cas9-mediated knockdown of USP29 in HeLa cells resulted in cell cycle arrest at the G0/G1 phase. We also showed that USP29 knockdown hampered Cdc25A-mediated cell proliferation, migration, and invasion of cancer cells in vitro. Moreover, NSG nude mice transplanted with USP29-depleted cells significantly reduced the size of the tumors, whereas the reconstitution of Cdc25A in USP29-depleted cells significantly increased the tumor size. Altogether, our results implied that USP29 promoted cell cycle progression and oncogenic transformation by regulating protein turnover of Cdc25A. 相似文献
3.
研究带有干扰观测器(Disturbance observer,DOB)的反馈控制系统对模型不确定性鲁棒稳定的充分条件,在此基础上,选取满足此充分条件的加权函数,使得标准H∞干扰观测器设计方法保证对受控对象参数变化的鲁棒稳定性.提出了在H∞干扰观测器设计中兼顾鲁棒性设计指标和结构约束的频率加权函数的选取方法.利用加权函数选取的自由度,在干扰观测器低通滤波器设计中,实现Q—滤波器在截止频率上的高峰幅度与干扰抑制性能之间的最佳折中,使得干扰观测器在满足其幅度指标的条件下,具有最优干扰抑制性能.实验结果表明该方法保证了闭环反馈系统的鲁棒稳定性,同时,具有实现其他设计指标的自由度. 相似文献
4.
玉米作为主食材料其淀粉呈多角形,蛋白质中缺少醇溶谷蛋白,不能形成粘弹性面团,限制了其应用,产品形式较少,口感较粗糙。对玉米粉进行改性处理,使其具有与小麦粉类似的加工性质,从而开发更多的产品,充分利用玉米的营养,扩大玉米粉的应用范围,改善产品的食用品质。 相似文献
5.
Triboelectric generators (TEGs) are devices that convert mechanical energy to electrical energy through triboelectric charging of different material surfaces at periodic contact. Typically, such devices consist of two dielectric contacting layers with electrodes attached on the non-contacting sides but alternatively, one material can simultaneously serve as both a contacting and an electrode material. In this work, we report the use of poly(3,4-ethylenedioxythiophene) (PEDOT) for TEG device were PEDOT film serves as both a contacting surface to PDMS and as an electrode. Two different PEDOT films were prepared on glass substrates by vapour-phase polymerization (VPP) and VPP combined with electropolymerization method and compared as TEG electrodes. Additionally, PEDOT/poly(1,6-hexanediol-co-citric acid) (PHC) composite films were prepared by using solution casting polymerization. These methods yielded PEDOT films with different morphology, surface roughness and conductivity. Best performance was demonstrated for the PEDOT film with the lowest surface roughness (1.88 nm RMS), prepared by VPP method, which generated peak current of 0.45 mA/m2 and power density of 95 W/m2, outperforming Sn doped In2O3 electrode approximately by threefold in the same experimental setup. 相似文献
6.
L. Ben Tahar H. Basti F. Herbst L.S. Smiri J.P. Quisefit N. Yaacoub J.M. Grenèche S. Ammar 《Materials Research Bulletin》2012,47(9):2590-2598
Highly crystalline stoichiometric Co1?xZnxFe2O4 (0 ≤ x ≤ 1) nanoparticles were successfully synthesized by the polyol process. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), transmission electron microscopy (TEM), infrared spectroscopy (IR), zero-field 57Fe Mössbauer spectrometry and magnetic measurements using a SQUID magnetometer were employed to investigate the effect of the substitution of Zn2+ ions for Co2+ ones on the structure, and the magnetic properties of the cobalt ferrite, CoFe2O4. The unit cell parameter almost increases linearly with increasing Zn concentration, x, following Vegard's law. The red and blue shifts observed for the metal-oxygen ν1 and ν2 IR vibration bands, respectively, were consistent with the preferential entrance of Zn2+ ions in tetrahedral sites. Besides, detailed magnetic investigation in correlation with the cation distribution has been reported. All the particles exhibit superparamagnetic behaviour at room temperature. In addition, the magnetic characteristics (blocking temperature, saturation magnetization, coercivity, Curie temperature) clearly depend on the chemical composition and cation distribution. Both the blocking temperature and Curie temperature decrease drastically with Zn composition, x, increase. Further, the saturation magnetization follows an almost bulk-like behaviour with values notably larger than that of the bulk, mainly attributed to cation distribution deviation. 相似文献
7.
Post-tensioning (PT) using a bundle of pre-stressed strands is a critical process for assembling pre-fabricated and modularized bridge members. However, the tension force gradually diminishes over time due to such factors as corrosion, creep, and steel relaxation. Such changes compromise the overall safety of such structures. In this study, an eddy-current-based tension-force-loss warning (EC-TFLW) technique is proposed to detect and warn automatically of excessive loss of tension force in a PT tendon. A ring-type eddy-current sensor (ECS) is mounted on the outer surface of a wedge holding a tendon, and the level of eddy current measured by the ECS is related to the tension force of the tendon. The advantages of the proposed technique include: (1) low power consumption, (2) low cost, (3) simple installation, and (4) automated warning. The performance of the proposed EC-TFLW technique was validated experimentally in a full-scale lab test of a 3.3-m long, 15.2-mm diameter, mono-strand tendon that was tensioned using a universal testing machine (from 20 to 180 kN). Statistical hypothesis testing using the chi-square distribution was applied to the measured eddy current signals, and if the decline in tension exceeded a certain level, a warning was sent out automatically. 相似文献
8.
9.
Globulization mechanism of the primary Al of Al−15Cu alloy during slurry preparation for rheoforming
J. Jayaraj Eric Fleury Ki-Bae Kim Jae-Chul Lee 《Metals and Materials International》2005,11(3):257-262
Semisolid slurries of Al-15Cu alloy were produced for rheoforming by a low temperature pouring technique. To investigate the
morphological change of the slurry in terms of the particle mean diameter and the roundness factor, samples were extracted
during the continuous cooling and the isothermal holding stage of the slurry by a simple technique of interrupt quenching.
Results demonstrated that the fine-grained equiaxed dendritic structure, which formed during low temperature pouring, is changed
to a globular structure when held at a semisolid temperature for sufficiently long holding time. With regard to the globulization
mechanism of the primary α-phase, local melting is considered to take place at the neck of equiaxed dendrites, leading to
the separation of small new particles during continuous cooling. These newly formed particles eventually grow during isothermal
holding in the semisolid temperature by obeying theD
3=Kt kinetic law, which suggests coarsening by Ostwald ripening. 相似文献
10.
《Food Control》2015
In the present study, the disinfection efficacy on fresh-cut cilantro of the combination of strongly acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW) was evaluated, in comparison with single slightly acidic electrolyzed water (SAEW) and single AcEW treatments. The populations of E. Coli O78 on inoculated cilantro treated by AlEW 5 min + AcEW 5 min, was not detected while 3.43 and 3.73 log10 CFU/g in the AlEW 2.5 min + AcEW 2.5 min and AcEW 2 min + AlEW 2 min + AcEW 2 min treatments respectively. Our results implied that the bactericidal abilities of the combination of AlEW and AcEW treatments were higher than that of single AcEW and SAEW, which also was demonstrated microscopically by scanning electron microscopy (SEM). Moreover, the efficacy of combination of AcEW and AlEW in reducing natural micro flora on fresh-cut cilantro was also evaluated compared with single AcEW and SAEW. The results showed that the combination of AlEW and AcEW had stronger sterilization ability than single AcEW and SAEW. Considering the utilizations of AlEW and disinfection efficacy, we suggest that the combination of AlEW and AcEW may also be a better choice in fresh-cut produce. 相似文献