全文获取类型
| 收费全文 | 170篇 |
| 免费 | 12篇 |
| 国内免费 | 4篇 |
专业分类
| 电工技术 | 1篇 |
| 综合类 | 17篇 |
| 化学工业 | 23篇 |
| 金属工艺 | 33篇 |
| 机械仪表 | 9篇 |
| 矿业工程 | 4篇 |
| 能源动力 | 21篇 |
| 武器工业 | 1篇 |
| 无线电 | 16篇 |
| 一般工业技术 | 32篇 |
| 冶金工业 | 11篇 |
| 自动化技术 | 18篇 |
出版年
| 2025年 | 3篇 |
| 2024年 | 6篇 |
| 2023年 | 25篇 |
| 2022年 | 7篇 |
| 2021年 | 5篇 |
| 2020年 | 10篇 |
| 2019年 | 7篇 |
| 2018年 | 2篇 |
| 2017年 | 10篇 |
| 2016年 | 7篇 |
| 2015年 | 9篇 |
| 2014年 | 10篇 |
| 2013年 | 13篇 |
| 2012年 | 15篇 |
| 2011年 | 12篇 |
| 2010年 | 4篇 |
| 2009年 | 5篇 |
| 2007年 | 1篇 |
| 2006年 | 2篇 |
| 2005年 | 1篇 |
| 2003年 | 1篇 |
| 2002年 | 1篇 |
| 2001年 | 2篇 |
| 2000年 | 1篇 |
| 1999年 | 5篇 |
| 1998年 | 1篇 |
| 1996年 | 1篇 |
| 1995年 | 1篇 |
| 1994年 | 1篇 |
| 1992年 | 3篇 |
| 1990年 | 2篇 |
| 1988年 | 4篇 |
| 1987年 | 2篇 |
| 1986年 | 2篇 |
| 1983年 | 1篇 |
| 1981年 | 1篇 |
| 1972年 | 1篇 |
| 1967年 | 1篇 |
| 1952年 | 1篇 |
排序方式： 共有186条查询结果，搜索用时 15 毫秒
161.
162.
Jin Cao Dongdong Zhang Yilei Yue Xuelin Yang Chenwu Yang Jingjing Niu Zhiyuan Zeng Pinit Kidkhunthod Suttipong Wannapaiboon Xinyu Zhang Jiaqian Qin Jun Lu 《Advanced functional materials》2023,33(42):2307270
The low cost and intrinsic safety of rechargeable aqueous zinc-ion batteries (ZIBs) contribute to their significant potential in grid-level energy storage systems. However, the limited cathode options still hinder the development of ZIBs, which always delivers poor rate capacities and cycling stability. Herein, Monoclinic phase H3.78V6O13 microspheres with a stable internal framework and intrinsic metallic properties as a high-performance cathode for ZIBs are proposed and utilized. The reversible Zn2+insertion/de-insertion mechanism in H3.78V6O13through ex situ X-ray diffraction, X-ray absorption near-edge structure, and in situ Raman involves the enlargement/shrink of interplanar distance, the decrease/increase of the V valance, and the open/recombine of V─O/V─V bonds. Further, experiments and theoretical calculations elucidate the superior electrochemical performance and extraordinary reaction kinetics in H3.78V6O13. The as-prepared H3.78V6O13 cathode delivers high specific capacity of 406 mAh g–1 at 0.1 A g–1, excellent structure stability with 100% manifested after 120 cycles at 0.5 A g–1, 72.9% retained after 15 000 cycles at 10 A g–1. This research offers distinctive perspectives on the development of high-performance cathode materials for ZIBs and enhances the understanding of the electrochemical reaction mechanisms of vanadium oxides. 相似文献
163.
The investigation described in this paper focuses on the velocity effect of dynamic magnetization and magnetic hysteresis due to rapid relative motion between magnetizer and measured specimens in high-speed magnetic flux leakage (MFL) inspection. Magnetization intensity and permeability of ferromagnetic materials along with the duration of dynamic magnetization process were analyzed. Alteration of the intensity and distribution of magnetic field leakage caused by permeability of specimen were investigated via theoretical analysis and finite-element method (FEM) combined with the actual high-speed MFL test. Following this, a specially designed experimental platform, in which motion velocity is within the range of 5 m/s–55 m/s, was employed to verify the velocity effect and probability of a high-speed MFL test. Preliminary results indicate that the MFL technique can achieve effective defect inspection at high speeds with the maximum inspection speed of about 200 km/h being verified under laboratory conditions. 相似文献
164.
《Intermetallics》2015
Fe-based soft-magnetic metallic glasses (MGs) of Fe80−xCrxP9C9B2 (x = 0, 2, 5, 8 and 16 at.%) with high glass-forming ability (GFA), good soft-magnetic properties and high corrosion resistance are fabricated. With the addition of Cr to FePC-based alloys, the GFA and saturation magnetization (Ms) slightly decrease while the corrosion resistance effectively increases. The Fe–Cr–P–C–B BMGs exhibit good GFA and fully glassy rods can be produced up to 1.8 and 1.5 mm in diameter for the 2 and 5 at.% Cr added alloys, respectively. The alloys with 2 and 5 at.% Cr addition also show good soft-magnetic properties featured by high Ms of 1.16 and 1.04 T, low coercivity of 2.7 and 2.2 A/m, respectively. Besides, the corrosion behavior of the alloys was studied by immersion tests and potentiodynamic polarization measurements. It was found that the addition of Cr efficiently enhances the corrosion resistance of Fe–Cr–P–C–B alloys and the glassy alloy with 5 at.% Cr addition exhibits better corrosion resistance in comparison with the stainless steel SUS304 in 3 mass% NaCl solution. The combination of large GFA, good soft-magnetic properties, high corrosion resistance as well as low cost makes the Fe–Cr–P–C–B alloys as promising soft-magnetic and anti-corrosive materials for industrial applications. 相似文献
165.
《Acta Materialia》1999,47(3):1043-1052
The microstructure of nickel-base superalloys with differently shaped γ′ precipitates determines their excellent high-temperature behaviour. A reliable quantitative determination of volume fraction and particle size distribution (PSD) of these precipitates is difficult, since the size of the precipitates is often below 100 nm. With an atomic force microscope (AFM), sections through specimens are analysed with a resolution in the nanometre range, which allows a quantitative determination of the γ′ volume content and PSD for different superalloys. Thus, determined volume fractions for the γ′ phase in the superalloys CMSX-6 and Waspaloy amount to 56% and 27%, respectively. A combination of an AFM with a nanoindentation system also allows the measurement of local mechanical properties such as hardness and elasticity. These quantities are determined for the first time directly on the superalloys CMSX-6 and Waspaloy for the γ′ and matrix phases, separately. The γ′ phase in both alloys shows a significantly higher but different hardness than the matrix phase, whereas the moduli of elasticity are similar. A depth dependence of the hardness was found for very small indentations. 相似文献
166.
N+缓冲层设计对PT-IGBT器件特性的影响至关重要。文中利用Silvaco软件对PT-IGBT的I-V特性进行仿真。提取相同电流密度下,不同N+缓冲层掺杂浓度PT-IGBT的通态压降,得到了通态压降随N+缓冲层掺杂浓度变化的曲线,该仿真结果与理论分析一致。对于PT-IGBT结构,N+缓冲层浓度及厚度存在最优值,只要合理的选取可以有效地降低通态压降。 相似文献
167.
目标点击操作中不同方向对笔压性能影响的研究 总被引：1，自引：0，他引：1
在基于Fitts定理的目标点击任务中,不同的操作方向可能会对笔尖压力的使用性能产生影响,但Fitts定理却忽视了对方向因素的考察。因此,采用实证研究方法设计了两类方向,一类是矩形条菜单方向(北-南,西-东,东北-西南和东南-西北),另一类是压力增减方向(分别在4种方向的矩形条菜单上逐步增大压力(Pressure Increase)或逐步减小压力(Pressure Decrease)来选择两个目标,分别称之为PI Pointing和PD Pointing操作),考察了在基于Fitts定理的点击任务中不同方向对笔压使用性能的影响。实验要求12名实验者依次获取并选择矩形条上的两个不同间距和不同大小的目标。实验结果表明,不同的压力增减方向对笔压的使用性能有影响,而不同的矩形条菜单方向对笔压的使用性能没有显著性差异。本研究对基于笔压使用的用户交互界面设计具有帮助和指导作用。 相似文献
168.
169.
《International Journal of Hydrogen Energy》2017,42(40):25608-25618
In this study, the effects of TiO2 and TiOSO4 on the precipitation of the positive electrolyte of vanadium redox battery (VRB) systems were investigated. TiO2 and TiOSO4 were used as anti-precipitating agents for V(V) ions at 40 and 60 °C. The optimum amounts and electrochemical properties of additives were determined by electrochemical methods such as cyclic voltammetry and electrochemical impedance spectroscopy. The optimum amount of additives was identified as wt% 0.004 and 0.003 for TiO2 and TiOSO4, respectively. The structural features and composition of electrodes were investigated by scanning electron microscopic and energy-dispersive X-ray analysis. A plausible reaction mechanism was also proposed for redox reaction occurring on the positive electrode of a VRB. The concentration of V(V) ions in the additive including electrolyte were higher than that of blank solution at the end of the thermal precipitation tests. According to thermal and electrochemical studies, TiO2 and TiOSO4 can be useful additives for the positive electrolyte of a VRB. 相似文献
170.
《Ceramics International》2017,43(8):6371-6376
Hybrid nanocomposites consisting of uniform Fe3O4 nanoparticles and boron nitride (BN) nanospheres were synthesized via an ethanol-thermal reaction method. The spherical BN nanoparticles (BNNSs) with average diameter 150 nm have been uniformly coated with dense ultra-small Fe3O4 nanoparticles (with average diameter of 10 nm), forming novel Fe3O4@BNNS nanocomposites. Magnetic measurement by using vibrating sample magnetometer (VSM) indicates that the Fe3O4 coating is superparamagnetic, and the nanocomposites can be physically manipulated at a low magnetic field. Preliminary biocompatibility study has also been performed to evaluate the toxicity of the nanocomposites. The nanocomposites show cytocompatibility at low concentration and have little effect on cell viability of MCF-7, MCF-10 and Hela cell lines. The Fe3O4@BNNS nanocomposites may find a wide range of potential applications including water treatment, catalysts, carriers for boron neutron capture therapy and magnetic-targeted drug delivery. 相似文献