全文获取类型
收费全文 | 270篇 |
免费 | 17篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 10篇 |
综合类 | 14篇 |
化学工业 | 48篇 |
金属工艺 | 20篇 |
机械仪表 | 7篇 |
建筑科学 | 4篇 |
能源动力 | 23篇 |
无线电 | 77篇 |
一般工业技术 | 88篇 |
冶金工业 | 7篇 |
自动化技术 | 9篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 11篇 |
2020年 | 19篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 6篇 |
2012年 | 21篇 |
2011年 | 18篇 |
2010年 | 11篇 |
2009年 | 30篇 |
2008年 | 14篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有307条查询结果,搜索用时 15 毫秒
1.
《Ceramics International》2022,48(17):24454-24461
Enhancement of thermoelectric properties by virtue of decreased electrical resistance through grain boundary engineering is realised in this study. A robust strategy of optimisation of the transport properties by tuning the energy filtering effects at the interfaces by decreasing the interfacial electrical resistance is achieved in LaCoO3 (LCO). This is accomplished by the incorporation of multilayer graphene within the parent LCO matrix containing multi-scale nano/micro grains. The present work has attained a substantial increment in electrical conductivity from a value of 96 Scm-1 for bare LCO to ~5300 Scm-1 at 750 K by incorporating 0.08 wt% multilayer graphene in LCO. No significant change in thermal conductivity is observed due to the presence of multilayer graphene in LCO. A zT of 0.33 at 550 K for 0.08 wt% multi-layer graphene incorporated LCO composite is achieved which is the highest thermoelectric figure of merit value for undoped LCO reported until now. 相似文献
2.
Trinh Nguyen Thi Phuoc Cao Van Duc Duong Viet Viet Dong Quoc Hayeong Ahn Viet Anh Cao Min-Gu Kang Junghyo Nah Byong-Guk Park Jong-Ryul Jeong 《Ceramics International》2021,47(12):16770-16775
In this study, we examined the dependence of surface morphology and spin Seebeck effect (SSE) voltages on the poly[vinylpyrrolidone] (PVP) concentration in polycrystalline Y3Fe5O12 (YIG) ultrathin films on a silicon substrate synthesized by metal-organic decomposition followed by a crystallization process. During fabrication, PVP concentrations of 0.5–2 g were used while all other conditions remained fixed. Atomic force microscopy and grazing incidence X-ray diffraction (XRD) measurements revealed a strong dependence of crystallinity and sample morphology on PVP concentration. The 1-g PVP sample had the smoothest surface, with a root mean square roughness of 0.2 nm, as well as superior bulk uniformity with respect to the shape and intensity of XRD reflection peaks. This was confirmed by scanning electron microscopy measurements of a cross-section of the sample that revealed a uniform film without pores. SSE measurements were performed to obtain the output SSE voltages (VSSE) of all samples, to which a platinum layer was added as a spin-detection layer. Repeatedly, the 1-g PVP sample had the best performance, demonstrating the importance of film crystallinity and morphology in the spin-to-charge conversion efficiency of YIG films. 相似文献
3.
为了获得一种稳定可控的能源,提出一种栅控石墨烯热电器件。通过对石墨烯通道的载流子输运机理的分析,获得了温度和栅压对通道电阻的影响。依据半经典Mott公式推导了石墨烯塞贝克系数的表达式,同时给出了石墨烯的电导率和热导率模型。最后通过有限元分析(FEA)建模获得不同栅压条件下的器件温度,当栅极电压VB=0 V时,石墨烯热电器件热端和冷端温度差为30 K;当VB=6 V时,最大温差达到50 K;当VB=30 V时,最小温差只有10 K。结果表明,栅压对热电器件的性能有明显的调控性。该研究可为石墨烯热电器件的设计提供理论参考。 相似文献
4.
Seung-Hwan Lee Jin-Myung Choi Jae-Hong Lim Jozeph Park Jin-Seong Park 《Ceramics International》2018,44(2):1978-1983
The thermoelectric properties of aluminum-doped tin oxide (ATO) thin films synthesized by thermal atomic layer deposition (ALD) were studied with respect to the aluminum concentration. The overall aluminum content in each layer was modulated by adjusting the relative number of tin oxide (SnO2) and aluminum oxide (Al2O3) growth cycles, where a sequential process involving n cycles of SnO2 growth followed by 1 cycle of Al2O3 deposition was performed (building up a super-cycle). The electrical conductivity (620 S/cm), free carrier concentration (1.23x1021 cm-3), and power factor (0.49 mW/K2m) increase until their maximum values are reached when the Al content is approximately 1.50 at% of the cations, and decrease as more Al is added in. On the other hand, the Seebeck coefficient decreases monotonically as the Al content increases up to about 2.88 at%, and begins to increase with further Al doping. Here the thermoelectric efficiency is therefore determined primarily by the free carrier concentration, while the Seebeck coefficient appears to be influenced by the overall crystal structure. 相似文献
5.
Thin Film Thermoelectric Metal–Organic Framework with High Seebeck Coefficient and Low Thermal Conductivity 下载免费PDF全文
6.
《Ceramics International》2019,45(12):14953-14957
Since the p-type BiCuSeO has been well developed in 2010, the maximum ZT value > 1.5 was achieved. Recently, the extensive research on n-type BiCuSeO is of interest to match its p-type counterpart. In this work, we found that n-type BiCuSeO can be successfully obtained in Bi1.04Cu1.05Se0.99X0.01O by using halogens (X = Cl, Br, I) doping. The first-principle calculations on the electronic band structure of BiCuSeO show that the Fermi levels were shifted into the conduction band by halogens doping at Se site. Both electrical transport properties and Hall measurements indicate that halogens are effective electron-dopants to realize n-type BiCuSeO. Interestingly, the results of temperature-dependent Seebeck coefficients elucidate a p-n-p type transport behavior, which experience less and less pronounced with increasing heating-cooling measurement cycles until n-type transports disappeared. Our results indicate that even though a large negative Seebeck coefficient (– 500 μV/K) can be realized in n-type BiCuSeO, but these n-type behaviors are reversible and unstable due to the fragile bonding in Cu-X (X = Cl, Br, I), and thus halogens losing upon several measurement cycles for heating and cooling. Even though our results indicate that the obtained n-type BiCuSeO is not stable through halogens doping, the calculated projected density of states elucidate that a high-performance n-type BiCuSeO can be expected by electron-doping at Bi sites. 相似文献
7.
8.
热电材料,是一种能实现电能与热能交互转变的材料,可用于温差发电、热电制冷等。到目前为止,所研究的热电材料一般都为固体材料或者高温条件下的液态金属,尚未见文献在电解质溶液热电性能方面有过报道。相关的研究表明,低维度纳米多孔化结构可能成为提高材料热电性能的重要途径,为此,进行了以碳纳米管(canbon nanotubes,CNTs)堆积床为骨架,在其中注入电解质溶液的试验研究,发现其表观塞贝克系数(Seebeck,S)可提高一个数量级,而导电系数在碳纳米管体积分数较小的情况下几乎保持不变,从而可能使热电材料的热电优值ηZT(themoelectric figure of merit,ZT)再提高1~2个数量级,而ηZT直接决定热电设备的转换效率。 相似文献
9.
10.