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排序方式: 共有631条查询结果,搜索用时 18 毫秒
1.
《Ceramics International》2022,48(1):164-172
In this work, novel rhombus-shaped cerium oxide sheets (RCOS) were prepared using a facile, soft-chemical approach that was low cost, scalable, eco-friendly, and industrially viable. The structural and surface chemical properties were studied using spectroscopic and electron microscopic techniques. The synthesized RCOSs were used for the methanol oxidation reaction and supercapacitor studies. The RCOSs showed a current density of ~227 mA cm–2 with an onset potential of ~0.37 V. The electrocatalyst activity retention was 92% of the initial activity after 500 CV cycles. A specific capacitance of 481 F g–1 at a scan rate of 5 mV s–1 was observed for supercapacitor application. The specific capacitance retention was ~83% after 500 cycles. The huge specific surface area and conductivity associated with cerium oxide sheets were responsible for the enhanced electrochemical properties. This is the first report on the synthesis of rhombus-shaped cerium oxide sheets, which leads to new avenues for synthesizing novel cerium-based electrode materials. 相似文献
2.
Yao Song Zhanhua Su Zhifeng Zhao Shuangyan Lin Dan Wang 《Ceramics International》2021,47(15):21367-21372
Herein, [As2IIIAsVMo8VIV4IVO40]2[CuICu2II(pz)4]2·9H2O/polyaniline/reduced graphene oxide (pz = pyrazine, abbreviated to As3Mo8V4/PANi/rGO) composite is first assembled, characterized and systematically explored for its supercapacitor performance. As3Mo8V4/PANi/rGO composite shows a exceptional specific capacitance (2351 F g?1 at 1 A g?1) and outstanding cyclic stability (96.9% after 5000 cycles). The symmetric supercapacitor exhibits high specific capacitance of 1295 F g?1 at 1 A g?1 and excellent energy density of 88.1 Wh kg-1 at power density of 349.6 W kg-1, while maintaining a notable capacitance retention of 85.7% after 5000 cycles at 2 A g-1. The above results confirm the potential application of As3Mo8V4/PANi/rGO composite in energy storage devices. 相似文献
3.
《Ceramics International》2022,48(5):6157-6165
Electrochemical system centered on hierarchically carbon-based metal sulphide assemblies are of great fame for competent supercapacitors. Herein, the synthesis of a hierarchical CNT anchored MoS2–Bi2S3 nanocomposite is reported. Attractively, a vertically grown Bi2S3 nanorods supported on MoS2 nanosheets with carbon framework acts as a highly effective electrode in alkaline electrolyte. More interestingly, this hierarchical structure and synergetic upshot of CNT and composites provide excess coverage of active sites with improved conductivity and stability. Advancing from the physical and compositional properties of nanocomposites, the specific capacitance of MoS2–Bi2S3@CNT composites is measured to be 1338 F/g at 10 mV/s, columbic efficiency of 99.5% over 10000 cycles and long-term stability (60% retention at 0.5 A g?1 over 2000 cycles and 34.6% up to 10000 cycles). The success of this MoS2–Bi2S3@CNT composite may be attributed to the structural advantages, admirable cyclic stability, and better capacitance retention for supercapacitor applications. 相似文献
4.
《International Journal of Hydrogen Energy》2021,46(77):38416-38424
Marigold flower (MG; Tagetes erecta) derived Graphene quantum dots (GQDs) have been successfully reported for the fabrication of supercapacitor electrodes in charge storage devices. The GQDs have been synthesized through a hydrothermal route using biomass viz. Waste material (MG) without adding any hazardous chemicals. The successful formation of GQDs as elaborated has been confirmed by various analytical characterization techniques. The as-synthesized GQDs have been electrodeposited on the Ni foil (working electrode) with the help of PVDF (binder) and subsequently, cyclic voltammetry (CV) has been conducted to access specific capacitance, energy density, and other parameters. Moreover, the galvanometric charge/discharge (GCD) technique has been employed due to its accuracy and reliability. Maximum areal specific capacitance has been found as 1.6008 F/cm2 with the current density of 2.0 A/g even after loading a little amount of material on the electrode. The high magnitude of columbic efficiency (160.08), energy density (17.78 Wh/kg), and specific capacitance of 200 F/g at current density 2.0 A/g within a voltage range of −0.55 V to +0.25 V in 2 M KOH electrolyte solution indicate a good electrocapacitive performance of the as-synthesized material. Moreover, the as-synthesized GQDs have shown excellent capacitive retention after 1000th cycles which clearly embarks its sustainable electrocapacitive nature and henceforth offers outstanding potential for the applications in energy storage devices like supercapacitors. 相似文献
5.
Zhi Zhou Jing-Pei Cao Yan Wu Qi-Qi Zhuang Xiao-Yan Zhao Yu-Lei Wei Hong-Cun Bai 《International Journal of Hydrogen Energy》2021,46(44):22735-22746
Waste sugar solution (WSS), a waste by-product of manufacturing vitamin C, contains abundant waste acids and organics. In this work, a N/O-enriched copolymer was synthesized via a facile polymerization via the hydrogen bonding of O-containing functional groups and melamine and the crosslinking of aldehyde groups. Subsequently, N-doped carbon spheres were prepared by a typical carbonation/activation method. Remarkably, benefiting from an ultrahigh specific surface area (3612 m2/g) and rich heteroatom content (4.3% for N, 8.8% for O), the carbon spheres deliver a high specific capacitance of 387 F/g at 50 mA/g and 283 F/g at 5 A/g with 6 M KOH in two-electrode system. The assembled symmetric electric double-layer capacitor exhibits high energy density of 10.83 Wh/kg at 11.10 W/kg. This research provides a facile method for preparing N/O-doped carbon spheres by WSS, and confirms the excellent electrochemical performance of WSS-derived carbons in energy storage applications. 相似文献
6.
《Ceramics International》2019,45(14):17216-17223
To obtain a battery-type ceramic electrode material for supercapacitors, we used a metal-organic framework (HKUST-1) as a template to prepare ceramic material Cu9S8@C. Firstly, we adopted the calcination–vulcanization method to synthesize Cu9S8@C. Then we deposited it onto a carbon fiber cloth and employed it. Moreover, polypyrrole PPy/Cu9S8@C-CC nanocomposite electrodes were prepared via electrochemical deposition. By means of high-temperature calcination and vulcanization, the copper atoms of HKUST-1 were successfully transformed into Cu9S8 nanoparticles, and the organic ligand was carbonized into amorphous carbon in Cu9S8@C. The results showed that the PPy/Cu9S8@C-CC electrode presented a specific capacitance of 270.72F/g at a scan speed of 10 mV/s in a 1 M KCL aqueous solution. This value was much higher than that of Cu9S8@C-CC and Cu9S8-CC electrodes, as confirmed by the results of electrochemical test. At a scan rate of 10 mV/s, the capacitance retention rate for PPy/Cu9S8@C-CC after 3000 cycles was 80.36%, indicating its superior cycle characteristics. Moreover, PPy/Cu9S8@C-CC exhibited good frequency response. These results indicate that PPy/Cu9S8@C is an ideal electrode material for energy storage and conversion applications. 相似文献
7.
Atanu Roy Apurba Ray Samik Saha Sachindranath Das 《International Journal of Hydrogen Energy》2018,43(14):7128-7139
Polyaniline-multiwalled carbon nanotube (PANI-MWCNT) composite synthesized through chemical polymerization is investigated as a possible electrode material for supercapacitor as well as an electro-catalyst for hydrogen evolution reaction (HER) in acidic medium. UV–Vis spectroscopy, FTIR spectroscopy and field emission scanning electron microscopy (FESEM) have been used to characterize the electrode material. The binder-free electrodes were prepared and they exhibit a specific capacitance of 540.29 F g?1 at a scan rate of 2 mV s?1 in 1 M H2SO4 electrolyte. The material exhibits excellent pseudocapacitive behaviour due to the presence of PANI with long-term cyclic stability of 87.4% retention after 5000 cycles. PANI-MWCNT composite also shows good HER activity, with overpotential of ?395 mV. 相似文献
8.
《International Journal of Hydrogen Energy》2020,45(23):13080-13089
Layered double hydroxide (LDH) is potentially excellent supercapacitor (SC) materials, but the low conductivity and easy agglomeration limit the further improvement of their electrochemical properties. Therefore, LDHs are requisite to grow on some conductive substrates to produce high-performance SC. In this paper, the conductive two-dimensional (2D) transition metal carbides, nitrides and carbonitrides (called MXene) were explored as the substrate to directly deposit NiFe-LDH nanosheets by a one-step hydrothermal method, then a three-dimensional (3D) porous NiFe-LDH/MXene electrode was obtained. The morphology and electrochemical performance of the composite electrodes were analyzed and investigated. The results show that the NiFe-LDH/MXene electrode has larger specific capacitance (720.2 F/g) than NiFe-LDH (465 F/g), and the capacitance of the composite electrode retained 86% after 1000 cycles (only 24% for NiFe-LDH), showing excellent cycle stability. The improved electrochemical performance of the composites is caused by the stable sheet-like structure of NiFe-LDH during charge-discharge time and the conductive network formed by the MXene, which can accelerates electron transport. In addition, the asymmetric SC based on NiFe-LDH/MXene positive electrode display a power density of 758.27 W/kg at an energy density of 42.4 Wh/Kg. These results indicate the NiFe-LDH/MXene composites can be applied as the novel candidate of high-performance SC electrodes. 相似文献
9.
This paper presents a hybrid power and energy source supplied by a proton exchange membrane fuel cell (PEMFC) as the main power source in an uninterruptible power supply (UPS) system. To prevent the PEMFC from fuel starvation and degradation and realize their seamless linking in the hybrid UPS system, the power and energy are balanced by the battery and/or supercapacitor (SC) as two alternative auxiliary power sources. Based on the modeling and sizing of hybrid power and energy components, the power and energy management strategies and efficiency measurements of four operating modes in UPS system are proposed. To evaluate the proposed strategies, an experimental setup is implemented by a data acquisition system, a PEMFC generating system, and a UPS system including AC/DC rectifier, DC/AC inverter, DC/DC converter, AC/DC recharger and its intelligent control unit. Experimental results with the characteristics of a 300 W self-humidified air-breathing of PEMFC, 3-cell 12 V/5 Ah of batteries, and two 16-cell 120 F/2.7 V of SCs in parallel corroborate the excellent management strategies in the four operating modes of UPS system, which provides the basis for the optimal design of the UPS system with hybrid PEMFC/battery/SC power sources. 相似文献
10.
An in-situ polymerization method has been employed to prepare CuO/PANI nanocomposite. The prepared samples have been characterized by X-ray diffraction (XRD), FTIR spectroscopy, field emission scanning electron microscopy (FESEM), and BET analysis. Application of the prepared samples has been evaluated as supercapacitor material in 1 M Na2SO4 solution using cyclic voltammetry (CV) in different potential scan rates, ranging from 5 to 100 mV s−1, and electrochemical impedance spectroscopy (EIS). The specific capacitance of CuO/PANI has been calculated to be as high as 185 F g−1, much higher than that obtained for pure CuO nanoparticles (76 F g−1). Moreover, the composite material has shown better rate capability (75% capacitance retention) in various scan rates in comparison with the pure oxide (30% retention). EIS results show that the composite material benefits from much lower charge transfer resistance, compared to CuO nanoparticles. Moreover, much better cyclic performance has been achieved for the composite material. 相似文献