全文获取类型
收费全文 | 47篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 7篇 |
金属工艺 | 11篇 |
机械仪表 | 1篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
无线电 | 3篇 |
一般工业技术 | 17篇 |
冶金工业 | 2篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2017年 | 3篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 1篇 |
1999年 | 2篇 |
排序方式: 共有55条查询结果,搜索用时 15 毫秒
1.
用高能球磨采用两种方案制备了FeCo MnO体系,并用X射线衍射和振动样品磁强计对其结构和磁性质做了分析.发现采用直接氧化Mn而得到MnO的方法,所得体系的MnO较纯;而通过分解MnCO3得到MnO的体系,MnO纯度较低,有较多Mn3O4杂质,两种方法制备的FeCo MnO体系的矫顽力和剩磁比都比单纯FeCo体系的增加很多,且前一种方法比后一种方法制备的FeCo MnO体系的矫顽力和剩磁比较大.然后研究了球磨时间及退火处理对FeCo MnO体系矫顽力及剩磁比的影响,发现球磨时间为120h体系的矫顽力和剩磁比最大;经过退火处理后,体系的矫顽力和剩磁比都有较大幅度的增加. 相似文献
2.
3.
在高精度磁环地音探测器中,磁路的设计至关重要。采用辐向磁环的设计思想,突破了常规的柱状磁路设计,并且在磁钢材料的选择上采用了新型的铁钴基材料。通过实验测试可知均匀气隙磁场宽度增加到11.Omm,磁环地音探测器的失真度也极大地降低了,其失真度小于O.05%. 相似文献
4.
Structural and optical behavior of electrodeposited black chrome‐graphite encapsulated FeCo nanoparticles composite coatings
下载免费PDF全文
![点击此处可从《国际能源研究杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Black chrome‐graphite encapsulated FeCo nanoparticles (BC‐GEFeCo NPs) composite coatings were electrodeposited on substrates such as stainless steel, Cu, and Ni‐coated Cu. The major content of the deposited film is contributed by Cr, Fe‐Cr, Fe2AlCr, and FeCr0.29Ni0.16C0.06 as deduced from X‐ray diffraction. The root‐mean‐square roughness value of black chrome on Ni‐coated Cu employing PbSb anode is measured by atomic force microscopy (nanoindentation) studies as 57.176 nm, which is in satisfactory agreement with the literature value of 53.83 nm. With the addition of GEFeCo Nps, the root‐mean‐square roughness value for BC‐GEFeCo composite coatings on Ni‐coated Cu increases approximately 6.1 times that of black chrome surface. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
用KBH4作为还原剂,采用化学还原法制备FeCo纳米粒子,然后在400~600℃下退火。利用X射线衍射仪、扫描电镜、X射线光电子能谱仪和振动样品磁强计对FeCo纳米粒子进行表征,用网络矢量分析仪测定其电磁参数,并分析FeCo的吸波性能,研究退火温度对FeCo纳米粒子吸波性能的影响。结果表明,化学还原法制备的FeCo纳米粒子,在厚度为5 mm时对频率为2.24 GHz电磁波的反射损耗最大,为-14.9 dB,损耗机制以介电损耗为主。随退火温度从400℃升高到600℃,FeCo纳米粒子的介电损耗逐渐减小而磁损耗逐渐增大,在400℃退火后的FeCo粒子具有最优的电磁匹配特性和最高的反射损耗,在厚度为3.55 mm时对4.48 GHz电磁波的反射损耗为-49.14 dB。 相似文献
6.
Yu Gu Yang Cao Huijuan Chi Qing Liang Yongji Zhang Youyi Sun 《International journal of molecular sciences》2013,14(7):14204-14213
The FeCo/Fe3O4 nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe3O4 are formed by one step. The structure of the FeCo/Fe3O4 nanocomposite was characterized by means of Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectrometer spectroscopy (EDX). They show that the mass ratio of FeCo/Fe3O4 strongly depends on the reaction temperature. Such various architectures follow a stepwise growth mechanism of the composites prepared in various reaction temperatures were also discussed. It indicates that this strategy is facile, effective and controllable for the synthesis of FeCo/Fe3O4 by the one-step method. Furthermore, the magnetic and wave-absorbing properties of the nanocomposites with various structures were investigated in detail. The results show that the FeCo/Fe3O4 with higher mass ratio has higher magnetic properties. Moreover, the FeCo/Fe3O4 nanocomposite shows high wave-absorbing properties (e.g., −37.9 dB), which are expected to apply in microwave absorbing materials. 相似文献
7.
开展了FeCo微波吸收材料的研制及其微观结构、磁性能和微波吸收特性的研究,主要是采用机械合金化的方法制备纳米晶Feco固溶体合金粉末,通过电磁参数的调整和改变提高吸收剂的微波吸收性能。研究表明:采用机械合金化制备的Feco合金粉末与常规羰基铁粉相比,饱和磁感应强度提高10%,磁导率和介电常数在一定频率范围大幅度提高;机械合金化制备的Feco合金粉末作为吸波材料的吸收剂,与常规羰基铁粉相比,在质量分数相同的情况下,微波反射率峰值频率向低端移动;FeCo合金型吸波材料在厚度一定的条件下,微波反射率峰值频率随FeCo吸收剂质量分数的提高而降低。 相似文献
8.
M.S. Lucas W.C. Bourne A.O. Sheets L. BrunkeM.D. Alexander J.M. Shank E. Michel S.L. SemiatinJ. Horwath Z. Turgut 《Materials Science and Engineering: B》2011,176(14):1079-1084
FeCo based nanocrystalline materials have excellent soft magnetic properties even at high temperature, but are limited to low frequency applications due to their relatively low electrical resistivities, ρe, resulting in high eddy current losses. Amorphous alloys of (Fe81Co19)84M9B7 where M = (Hf, HfTa, Ta) were prepared by meltspinning and annealed for increasing times at their respective crystallization temperatures. The nanocrystalline alloys had coercivities less than 0.4 Oe and saturation inductions greater than 1 T. The electrical resistivities of the amorphous ribbons were all similar with values of ρe ? 180 μΩ cm. After annealing at the crystallization temperature, the M = Ta alloy had the largest ρe of 140 ± 3 μΩ cm. The Ta alloy also had the best high frequency properties, with an initial permeability of 822 at 1 MHz. 相似文献
9.
10.
《International Journal of Hydrogen Energy》2019,44(31):16478-16486
Using low-cost nonprecious metals to replace Pt as hydrogen evolution reaction (HER) electrocatalyst is promising, but still limited by their efficiency and stability. Herein, with low-cost dicyandiamide and metal salts as precursor, FeCo alloy nanoparticles encapsulated in nitrogenated carbon nanotubes (FeCo-NCNTs) were facially synthesized as efficient HER electrocatalyst. Addition of iron as second element, though not facilitating the formation of carbon nanotube, was utilized to improve the physicochemical properties of metals. Via optimizing the atomic molar ratios of Fe/Co nanoparticles, the optimal Fe0.4Co0.6-NCNTs with thin carbon shell (c.a. 5–10 layer) and equally distribution of embedded alloy nanoparticles was found with outstanding HER activity. To achieve a current density of 10 mA cm−2, only overpotential of 50 mV, 157 mV and 202 mV were needed in acidic (0.5 M H2SO4), alkaline (1 M KOH), and neutral solutions. Its higher electrochemically active surface areas and lower electron transfer resistance may contribute to the excellent electrocatalytic HER. Furthermore, the illustrated current density slightly changed over 20 h, suggesting excellent stability. Hence, the present method provides cost-effective, high efficiency, and stable materials in developing the sustainable energy conversion systems. 相似文献