全文获取类型
收费全文 | 244篇 |
免费 | 5篇 |
国内免费 | 28篇 |
专业分类
电工技术 | 3篇 |
综合类 | 7篇 |
化学工业 | 26篇 |
金属工艺 | 13篇 |
机械仪表 | 3篇 |
能源动力 | 15篇 |
无线电 | 154篇 |
一般工业技术 | 51篇 |
冶金工业 | 3篇 |
自动化技术 | 2篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 15篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 7篇 |
2009年 | 14篇 |
2008年 | 15篇 |
2007年 | 9篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 9篇 |
2000年 | 15篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 17篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有277条查询结果,搜索用时 0 毫秒
31.
《International Journal of Hydrogen Energy》2020,45(16):9635-9647
In this work, a cascade structure among ZnSe, carbon membrane and TiO2 NTAs was constructed precisely. This carbon membrane bridged ZnSe and TiO2 composite exhibits excellent H2 evolution activity, the H2 evolution rate of ZnSe/C/TiO2 NTAs (866.76 μmol/cm2) is about 6.95 times higher than that of pure TiO2 NTAs (124.64 μmol/cm2) after 200 min irradiation. The introduction of carbon membrane can greatly facilitate the electron transfer from ZnSe to TiO2, ZnSe/C/TiO2 ternary composite exhibits the highest transient photocurrent density (1.05 mA/cm2) and the lowest impedance (677.6 Ω) among all the samples. Besides, the contact between TiO2 and electrolyte is improved after introducing carbon membrane, therefore C/TiO2 NTAs shows more positive flat band potential of (1.86 V) compared with TiO2 NTAs (0.50 V). It is also found that pure carbon powder can achieve H2 production under visible light irradiation, its sensitization effect can further improve photocurrent density of the composite under 500 nm light radiation, the electrons produced in carbon film can inject into TiO2, and holes from TiO2 can quickly transfer to carbon film, leading to excellent H2 evolution efficiency. 相似文献
32.
CdSe quantum dots (QDs) grown on ZnSe were investigated by various transmission electron microscopy (TEM) techniques including diffraction contrast imaging, high-resolution and analytical transmission electron microscopy both of plan-view as well as cross-section specimens. The size of the QDs ranges from about 5–50 nm, where from the contrast features in plan-view imaging two classes can be differentiated. In the features of the smaller dots there is no inner fine structure resolvable. The larger ones exhibit contrast features of fourfold symmetry as expected for pyramid-like islands. Corresponding simulations of diffraction contrast images of truncated CdSe pyramids with the edges of the basal plane orientated parallel to <100> are in relatively good agreement with this assumption. In TEM diffraction contrast imaging of cross-section samples the locations of the quantum dots are visualized by additional dark contrast features. The QDs have a distinct larger extension in growth direction compared to the almost uniformly thick CdSe wetting layer. The presence of the CdSe QDs was also confirmed by energy-dispersive X-ray spectroscopy. 相似文献
33.
《Ceramics International》2019,45(11):14084-14089
Undoped and Cu-doped ZnSe nanoparticle (NPs) were prepared and grown hydrothermally in aqueous media assisted by microwave irradiation (MWIR) at different synthesis conditions of pH and MWIR times. In the mentioned process, sodium hydroxide (NaBH4), used for preparing selenium ions source with dissolving it and selenium powder in deionized water. To investigate the structural aspects and nanoparticles morphology, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used. According to the results of XRD, no displacement was seen in the position of XRD peaks of ZnSe nanoparticles by altering the pH and microwave irradiation time. XRD analysis demonstrated cubic zinc blende NPs and TEM images indicated round shape morphology of them. Depending to the microwave irradiation time, upon the XRD outputs, the size of the synthesized NPs were in the range of 1.54–2.18 nm. In this research, for samples synthesized at different pHs (= 8, 10.2, 11.2 and 12.2), at two microwave irradiation time of 0 and 6 min, and also at the presence of Cu-dopant (with the contents of 0, 0.1,0.75 and 1.5%), structural characteristics such as dislocation density(δ), lattice strain(ε), size of nanoparticles (D) and full width at half maximum (FWHM:βhkl) have been evaluated upon the Scherrer and Williamson-Hall methods, in which undoped and ZnSe:Cu 0.1% synthesized at pH = 11.2 have the best crystalline quality; such results for the optimum samples, introduce them as promising materials in optoelectronic devices. The results of structural features obtained from Scherrer and Williamson-Hall approaches are highly intercorrelated and show the same trends with the variation of synthesis conditions. 相似文献
34.
《International Journal of Hydrogen Energy》2021,46(60):30818-30827
In this paper, dopamine hydrochloride (DPH) is introduced to synthesize ZIF-8@ZIF-67@DPH in the preparation of ZIF-8@ZIF-67. ZnSe/CoSe/NCDPH (N-doped carbon) composites are calcined in a high-temperature inert atmosphere with ZIF-8@ZIF-67@DPH as the precursor, selenium powder as the selenium source. ZnSe/CoSe/NCDPH has high discharge specific capacity, good cycle stability and outstanding rate performance. The first discharge capacity of ZnSe/CoSe/NCDPH is 1616.6 mAh g−1 at the current density of 0.1 A g−1, and the reversible capacity remains at 1214.2 mAh g−1 after 100 cycles, the reversible capacity is 416.7 mAh g−1 after 1000 cycles at 1 A g−1. Therefore, ZnSe/CoSe/NCDPH composites provide a new step for the research and synthesis of new stable, high-capacity, and safe high-performance lithium ion batteries. The bimetallic selenide composites not only have bimetallic active sites, but also can form synergistic effect between different metal phases, which can effectively reduce the capacity attenuation caused by volume expansion and reactive stress enrichment during lithium storage of metal oxide anode materials. Meanwhile, N-doped carbon can improve the conductivity and provide more active sites to store lithium, thus improving its lithium storage capacity. 相似文献
35.
The synthesis of monodispersed, starch-capped ZnSe nanoparticles via a facile, “green” and environmentally benign route at room temperature is being reported. The nanoparticles exhibited strong quantum confinement effect with respect to the bulk ZnSe. The transmission electron microscopy (TEM) image indicated that the particles were well dispersed and spherical in shape. The X-ray diffraction (XRD) analysis showed that the ZnSe nanoparticles were of the wurtzite structure, with average particle diameter of about 3.50 nm. The Fourier transform infrared (FT-IR) spectrum confirmed the presence of starch as passivating agent. 相似文献
36.
Susanne Siebentritt Timon Kampschulte Andreas Bauknecht Ulf Blieske Wolfgang Harneit Ulrich Fiedeler Martha Lux-Steiner 《Solar Energy Materials & Solar Cells》2002,70(4):447-457
ZnSe buffer layers for Cu(ln,Ga)Se2/buffer/ZnO solar cells have been prepared by metal organic chemical vapor deposition (MOCVD). Using photoassisted MOCVD, deposition temperatures down to 265°C are possible. It is shown that deposition temperatures well below 300°C are essential as well as deposition times not much longer than 3 min. Higher temperatures and longer deposition times lead to absorber degradation. With optimized buffer deposition efficiencies of 11% have been obtained on CIGS absorbers from the Siemens pilot production line. 相似文献
37.
脉冲激光烧蚀沉积ZnSe薄膜的研究 总被引:4,自引:2,他引:2
用 2 48nm的KrF准分子脉冲激光烧蚀ZnSe靶材沉积ZnSe薄膜。靶采用多晶ZnSe片 ,衬底采用抛光GaAs(10 0 )。衬底预处理采用化学刻蚀和高温处理。原子力显微镜 (AFM )观察显示在GaAs(10 0 )沉积的ZnSe薄膜的平均粗糙度为 3~ 4nm。X射线衍射 (XRD)结果表明ZnSe薄膜 (4 0 0 )峰的半高宽 (FWHM)为 0 4°~ 0 5°。对激光烧蚀团束的四极质谱分析表明烧蚀团束主要由Zn ,Se和 2Se组成 ,并由此推断ZnSe薄膜的二维生长模式。 相似文献
38.
蓝绿光半导体光电子器件的研究与发展现状 总被引:1,自引:0,他引:1
综述了CaN和ZnSe两大系列半导体光电子器件的研究与发展现状,重点讨论了材料的生长方法,给出了器件发展的最高水平。 相似文献
39.
40.
The effect of applied electric field on the electronic properties of spherical ZnSe/ZnS core/shell nanocrystals of experimentally relevant size is investigated by the atomistic tight-binding theory. Using this model, the calculations show that a range of electronic properties, including the single-particle spectra, atomistic characters, charge densities, excitonic energies, ground-state coulomb energies, overlaps of the electron and hole wave functions and oscillation strengths, all depend on the strengths of the applied electric field. The spatial distributions of the electron and hole wave functions are induced by the applied electric field. The analysis demonstrates a clear manipulation of the electronic properties of ZnSe/ZnS core/shell nanocrystals by introducing and varying the applied electric field strengths. According to the comprehensive investigations, I suppose that these atomistic computations will be of prospective help for experimental works concentrated on the new optoelectronic devices based on the applied electric field. 相似文献