全文获取类型
收费全文 | 267篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 76篇 |
金属工艺 | 36篇 |
机械仪表 | 20篇 |
能源动力 | 3篇 |
轻工业 | 1篇 |
武器工业 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 95篇 |
冶金工业 | 6篇 |
自动化技术 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 12篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 14篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 30篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 19篇 |
2007年 | 22篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有270条查询结果,搜索用时 46 毫秒
261.
Werner KraussDenis Schütz Michael NadererDenis Orosel Klaus Reichmann 《Journal of the European Ceramic Society》2011,31(9):1857-1860
A piezoelectric multilayer device based on bismuth-sodium-titanate ceramics (BNT) co-fired with Ag/Pd inner electrodes is described and its dielectric and piezoelectric properties are measured. The ceramic powder and tape was made by a water-based preparation process. After printing with Ag/Pd paste for inner electrodes these tapes were stacked to a multilayer device with 50 active layers. This device exhibited a large and temperature independent strain around 0.19% between 25 °C and 150 °C. The large strain is due to a field-induced phase transition. The low temperature dependence results from the broadening of the nonpolar phase by doping. 相似文献
262.
《Journal of the European Ceramic Society》2023,43(2):350-361
Solid solutions of BiFeO3 and BaTiO3 are promising lead-free piezoelectric materials, especially around the morphotropic phase boundary at 0.67BiFeO3-0.33BaTiO3. Still, these materials are challenged by phase instability and limited understanding of the processing-properties relationship. Here, we investigate mechanochemical activation and the use of BaTiO3 as seed particles for the 0.67BiFeO3-0.33BaTiO3 phase. Contrary to expectations from seeding in lead-based perovskites, the BaTiO3 seeds do not promote the 0.67BiFeO3-0.33BaTiO3 perovskite phase neither during the mechanochemical activation nor the subsequent sintering, but cause an inhomogeneous structure with remnant BaTiO3. This results in ceramics with weaker low-field piezoelectric response than that of the unseeded route, but with higher field-induced strain, even up to 150 °C. Both routes produce ceramics of high density and without significant secondary phases visible by X-ray diffraction. This demonstrates the advantage of mechanochemical activation and the possibility to tailor the piezoelectric response of 0.67BiFeO3-0.33BaTiO3 through the processing route. 相似文献
263.
264.
Jiangtao Zeng Liaoying ZhengGuorong Li Zhenzhu CaoKunyu Zhao Qingrui YinEkaterina D. Politova 《Journal of Alloys and Compounds》2011,509(19):5858-5862
(1 − x)K0.02Na0.98NbO3-xBaTiO3 ceramics were prepared by the solid state reaction method, and their electrical properties were investigated. The samples showed crystal structure changing from monoclinic to orthorhombic, and then to tetragonal, with an increase in BaTiO3 content. The addition of BaTiO3 markedly enhanced ferroelectric and piezoelectric properties of K0.02Na0.98NbO3 ceramics. Remnant polarization increased and coercive field decreased only in the samples with small amount of BaTiO3. Piezoelectric properties were improved with the addition of BaTiO3. The 0.9K0.02Na0.98NbO3-0.1BaTiO3 ceramics showed maximum piezoelectric constant (d33 = 160 pC/N), which was even comparable with that of (1 − x)K0.5Na0.5NbO3-xBaTiO3 ceramics. Their good piezoelectric properties, along with a low ferroelectric-ferroelectric transition temperature (TF-F), made the 0.9K0.02Na0.98NbO3-0.1BaTiO3 ceramics a potential candidate for lead-free piezoelectric applications. 相似文献
265.
Lang Wu Dingquan XiaoFei Zhou Yuancheng TengYuxiang Li 《Journal of Alloys and Compounds》2011,509(2):466-470
Lead-free (1 − x − y)Bi0.5Na0.5TiO3-xBaTiO3-yBi0.5Ag0.5TiO3 (BNT-BT-BAT-x/y, x = 0-0.10, y = 0-0.075) piezoelectric ceramics were synthesized by conventional oxide-mixed method. The microstructure, ferroelectric, and piezoelectric properties of the ceramics were investigated. Results show that a morphotropic phase boundary (MPB) between rhombohedral and tetragonal phases of BNT-BT-BAT-x/0.04 ceramics is formed at x = 0.06-0.08. The addition of BAT has no obvious change on the crystal structure of BNT-BT ceramics while it causes the grain size of the ceramics to become more homogenous. Near the MPB, the ceramics with x = 0.06 and y = 0.05-0.06 possess optimum electrical properties: Pr ∼ 42.5 μC/cm2, Ec ∼ 32.0 kV/cm, d33 ∼ 172 pC/N, kp ∼ 32.6%, and kt ∼ 52.6%. The temperature dependences of kp and polarization versus electric hysteresis loops reveal that the depolarization temperature (Td) of BNT-BT-BAT-0.06/y ceramics decreases with increasing y. In addition, the polar and non-polar phases may coexist in the BNT-BT-BAT-x/y ceramics above Td. 相似文献
266.
Bo Liu Qing Jiang Yuantai Hu Jiashi Yang 《International Journal of Engineering Science》2011,49(12):1435-1442
We study coupled face-shear and thickness-twist motions of piezoelectric plates of monoclinic crystals driven by lateral electric fields. The first-order theory of piezoelectric plates is used. Pure thickness modes and propagating waves in unbounded plates as well as vibrations of finite plates are studied. Both free vibrations and electrically forced vibrations are considered. Basic vibration characteristics including resonant frequencies, dispersion relations, frequency spectra and motional capacitance are obtained. Numerical results are presented for AT-cut quartz plates. The results are expected to be useful for the understanding and design of resonant piezoelectric devices using lateral field excitation. 相似文献
267.
Seok-Jung Park Kyung-Hoon Cho Hyeung-Gyu Lee Byung-Hyun Choi 《Materials Research Bulletin》2008,43(12):3580-3586
The addition of a small amount of CuO to the 0.95(Na0.5K0.5)NbO3-0.05CaTiO3 (0.95NKN-0.05CT) ceramics sintered at 960 °C for 10 h produced a dense microstructure with large grains due to the liquid phase sintering. Due to the negligible Na2O evaporation, poling was easy for all specimens sintered at 960 °C. The piezoelectric properties of the specimens were considerably influenced by the relative density, grain size and liquid phase amount. The high piezoelectric properties of d33 = 200 pC/N, kp = 0.37, and Qm = 350 were obtained for the 0.95NKN-0.05CT ceramics containing 2.0 mol% CuO sintered at 960 °C for 10 h. Therefore, the 0.95NKN-0.05CT ceramics containing a small amount of CuO are a good candidate material for lead-free piezoelectric ceramics. 相似文献
268.
Lead zirconate titanate (PZT) thin film is prepared by sol-gel method on Pt/Ti electrode/SiO2/Si wafer. Local poling is performed on the PZT film using an atomic force microscope (AFM). The topography and piezoelectric-induced (PEI) images on the polarized PZT film are recorded using AFM at piezo-responsive mode, operated with an AC voltage at varying frequencies. The best PEI image was obtained at the frequency around 300 kHz. It is explained that the change of piezoelectric vibrations and input noise signals with the frequency of AC modulation voltage affects the intensity of PEI images. 相似文献
269.
Gelcasting is a novel forming method for making high-quality ceramic parts by means of in situ polymerization where only a few percents of a polymerizable binder are needed. In this article the viscosities of lead zirconate titanate (PZT) suspensions with 15-52 vol.% solids loading were studied. After developing a concentrated PZT suspension with a low viscosity, gelcasting was successfully used to form PZT ceramic parts. Microstructures and piezoelectric properties of gelcast samples derived from suspensions with different solids loading were also investigated in comparison with those of die pressed ones. It was found that gelcast samples exhibited slightly stronger piezoelectric effect than the die pressed ones at the same sintering procedure. Based on the comparison of the density and pore structure results of the samples prepared by these two methods, their different piezoelectricity may be attributed to their microstructure difference. 相似文献
270.
Chun-Ming Wang Jin-Feng Wang Zhi-Gang Gai Ming-Lei Zhao Liang Zhao Jian-Xiu Xu Na Yin Cheng-Ju Zhang Shang-Qian Sun Guo-Zhong Zang Rui-Qing Chu Zhi-Jun Xu 《Materials Chemistry and Physics》2008,110(2-3):402-405
The Aurivillius type bismuth layer-structured compound potassium lanthanum bismuth titanate (K0.5La0.5Bi4Ti4O15) is synthesized using conventional solid-state processing. The phase analysis is performed by X-ray diffraction (XRD) and the microstructural morphology is conducted by scanning electron microscopy (SEM). The ferroelectric, dielectric and piezoelectric properties of K0.5La0.5Bi4Ti4O15 (KLBT) ceramics are investigated in detail. The remnant polarization (Pr) and coercive field (Ec) are found to be 8.6 μC cm−2 and 60 kV cm−1, respectively. The Curie temperature Tc and piezoelectric coefficient d33 are 413 °C and 18 pC N−1, respectively. 相似文献