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701.
Influence of temperature on thermal relaxation of exchange bias field in CoFe/Cu/CoFe/IrMn spin valve 下载免费PDF全文
《中国物理 B》2021,30(10):107501-107501
A multilayered spin valve film with a structure of Ta(5 nm)/Co_(75)Fe_(25)(5 nm)/Cu(2.5 nm)/Co_(75)Fe_(25)(5 nm)/Ir_(20)Mn_(80)(12 nm)/Ta(8 nm) is prepared by the high-vacuum direct current(DC) magnetron sputtering. The effect of temperature on the spin valve structure and the magnetic properties are studied by x-ray diffraction(XRD), atomic force microscopy(AFM), and vibrating sample magnetometry. The effect of temperature on the exchange bias field thermomagnetic properties of multilayered spin valve is studied by the residence time of samples in a reverse saturation field. The results show that as the temperature increases, the Ir Mn(111) texture weakens, surface/interface roughness increases, and the exchange bias field decreases. Below 200℃, the exchange bias field decreases with the residence time increasing, and at the beginning of the negative saturation field, the exchange bias field Hex decreases first quickly and then slowly gradually. When the temperature is greater than 200℃, the exchange bias field is unchanged with the residence time increasing. 相似文献
702.
703.
Pikul Wanichapichart Wirach Taweepreeda Safitree Nawae Pastraporn Choomgan Dan Yasenchak 《Radiation Physics and Chemistry》2012,81(8):949-953
Two types of bacterial cellulose (BC) membranes were produced under a modified H&S medium using sucrose as a carbon source, with (CCB) and without (SHB) coconut juice supplement. Both membranes showed similar crystallinity of 69.24 and 71.55%. After being irradiated with E-beams under oxygen limited and ambient condition, the results from water contact angle showed that only the irradiated membrane CCB was increased from 30 to 40 degrees, and irradiation under oxygen ambient condition provided the greatest value. Comparing with the control membranes, smaller water flux was the cases after electron beam irradiation which indicated a reduction of membrane pore area. However, the results from molecular weight cut off (MWCO) revealed that chain scission was greater for membrane SHB and its cut off was increased from 28,000 Da to more than 35,000 Da. FTIR analysis revealed some changes in membrane functional groups, corresponding with the above results. These changes initiated new property of cellulose membranes, an anti-fungal food wrap. 相似文献
704.
705.
《中国化学快报》2020,31(9):2478-2482
High-performance nanomaterial catalysts for hydrogen evolution reaction via electrochemical water splitting are significant to the development of hydrogen energy. In this work, we report a robust and highly active catalyst fabricated through direct electrochemical deposition of Pt nanodendrites at the surface of activated carbon (Pt NDs). Owing to the large electrochemically active area and the exposed (111) facet of Pt, Pt NDs exhibits outstanding activity towards hydrogen evolution reaction with a low requiring overpotential of 0.027 V at 10 mA/cm2 and Tafel slope of ≈ 22 mV/dec in acidic media. In addition, the hydrogen yield of Pt NDs is 30%–45% larger than that of commercial Pt/C at the same Pt loadings. Moreover, Pt NDs exhibits excellent long-term durability whose hydrogen production efficiency remains unchanged after six-hour hydrogen production, while the efficiency of commercial Pt/C catalyst decayed 9% under the same circumstance. Considering the superiority of catalytic activity and stability, this Pt NDs present great potentiality towards practical hydrogen production application. 相似文献
706.
以(CH_2OH)_2、NH4F和HCl为电解液,纯Ti片、CuCl_2和Na NO3为主要原料,联用阳极氧化和水热法制备CuO表面修饰锐钛矿TiO_2纳米管阵列锂离子电池负极材料(CuO/TiO_2)。使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱仪(EDS)、X射线光电子能谱仪(XPS)和X射线衍射(XRD),研究样品的形貌特征、元素分布、价态和微观物相组成。利用电池充放电测试仪和电化学工作站,探讨材料的电化学嵌锂性能。结果表明,表面修饰后的锐钛矿TiO_2纳米管阵列外侧出现了大量绒毛状纳米CuO,单个绒毛结构的宽度约4 nm,长度约10 nm。在0.3C的电流密度下进行恒电流充放电测试,首次放电容量为550 m Ah·g~(-1),充电容量为490 m Ah·g~(-1)。50次循环后,可逆电流容量仍保持在320 m Ah·g~(-1),具有良好的循环稳定性和电化学特性。 相似文献
707.
Transparent and translucent SnO2 aerogels with high specific surface area (>300 m2/g) have been prepared by sol-gel process using tetra(n-butoxy)tin(IV) as a starting compound, and supercritical drying technique for solvent extraction. Light scattering measurements reveal that the polymeric cluster size distribution in sol system is gradually broadened during sol-gel transition. SEM images show that the aerogels are made up of the cottonlike oxide agglomerates with a large number of pores. TEM images show that these aerogels seem to be self-similar at different magnifications. Their pore size distribution is pretty wide ranging from mesopore to macropore especially for that of translucent aerogel. 相似文献
708.
采用2004~2017年省际面板数据及门槛计量技术,实证分析了命令型、自愿型和经济型三类环境规制对绿色技术创新驱动产业升级的异质动态调节影响。研究发现,绿色技术创新显著驱动了国内产业升级,但绿色技术创新的产业升级效应具有明显的倒“U”型动态演化特征;环境规制在绿色技术创新驱动产业升级过程中发挥着“调控器”功能,不仅可扭转绿色技术创新对产业升级的不利影响,还有助于提升绿色技术创新的产业升级效应;绿色技术创新对产业升级的动态影响具有显著的异质环境规制调节特征,在命令型环境规制和经济型环境规制调节下均呈现正向“U”型特征,在自愿型环境规制调节下具有正向倒“U”型规律;现阶段环境规制的调节效果存在显著差异,从调控手段来看,命令型环境规制最佳、经济型环境规制次之、自愿型环境规制较弱。从空间差异来看,东部地区最明显、西部地区次之、中部地区较差。 相似文献
709.
710.
By using dynamical system method, this paper considers the (2+1)-dimensional Davey–Stewartson-type equations. The analytical parametric representations of solitary wave solutions, periodic wave solutions as well as unbounded wave solutions are obtained under different parameter conditions. A few diagrams corresponding to certain solutions illustrate some dynamical properties of the equations. 相似文献