全文获取类型
收费全文 | 72篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
综合类 | 2篇 |
化学工业 | 22篇 |
金属工艺 | 5篇 |
建筑科学 | 2篇 |
能源动力 | 1篇 |
轻工业 | 23篇 |
水利工程 | 2篇 |
石油天然气 | 5篇 |
无线电 | 5篇 |
一般工业技术 | 7篇 |
冶金工业 | 2篇 |
自动化技术 | 3篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2005年 | 1篇 |
2003年 | 3篇 |
2002年 | 1篇 |
排序方式: 共有79条查询结果,搜索用时 93 毫秒
1.
2.
为了降低稀布阵列的峰值旁瓣电平并抑制稀布阵列的栅瓣,提出了一种多目标粒子群与凸优化相结合的方向图综合算法。该算法将多目标粒子群优化(Multi-objective particles swarm optimization,MOPSO)作为全局搜索器,凸优化算法作为局部搜索器来搜索最优解,优化的变量不仅是阵元的权值,而且还加入了阵元位置这一参数,从而能够提供更多的自由度来控制稀布阵列的性能。基于30阵元的稀布圆形阵列的仿真结果表明:与单纯使用MOPSO算法相比,本文提出的用MOPSO算法优化阵元位置,凸优化算法优化阵元权值的联合优化算法,得到的栅瓣和峰值旁瓣电平都小于-19.3 dB。 相似文献
3.
Donghai Ding Lihua Lv Guoqing Xiao Jiyuan Luo Changkun Lei Yun Ren Shoulei Yang Pan Yang Xing Hou 《International Journal of Applied Ceramic Technology》2020,17(2):645-656
The paper investigated the effects of different amounts (0%, 3%, 6%, 9%) of in situ multilayer graphene/MgAl2O4 composite powders on the slag resistance, thermal shock resistance, and oxidation resistance of low-carbon MgO-C refractories. Comparing with commercial MgAl2O4, the MgAl2O4 in in situ multilayer graphene/MgAl2O4 composite powders has higher lattice strain of crystal, which can trap more Mn and Fe ions, resulting in the better slag resistance. The oxidation decarbonation layer of MgO-C specimen with 3% composite powders is 9.71 mm, which is lower than not only the specimen with other contents but also specimen containing carbon black/MgAl2O4 powders. Moreover, the residual strength ratio of the specimen C/MA-3 was 47.47%, which is 28.5% and 8.08% higher than specimens with no additive and with carbon black/MgAl2O4 powders, respectively. Both improving thermal shock and oxidation resistance properties are related with the unique nano structure, multilayer graphene in situ formed between MgAl2O4 grains, of added composite powders. The former is due to higher strain energy consumed by multi-deflection of cracks inside the multilayer graphene/MgAl2O4 composite powders. And the latter is due to the higher energy of oxidation activation of multilayer graphene/MgAl2O4 composite powders due to effective protection of multilayer graphene by MgAl2O4. 相似文献
4.
Lihua Lv Guoqing Xiao Donghai Ding Yun Ren Shoulei Yang Pan Yang Xing Hou 《International Journal of Applied Ceramic Technology》2019,16(3):1253-1263
In order to solve the bottleneck problems including uniform distribution, and oxidation resistance of nano carbons in oxide ceramics, C/MgAl2O4 composite powders were prepared with MgC2O4·2H2O, MgO2, Al2O3, and Al as raw materials via combustion method under argon atmosphere. The maximum adding amount of MgC2O4·2H2O is 34.34 wt%. The phase compositions and microstructures of combustion products were characterized through X-ray diffraction (XRD), scanning electron microscope (SEM)/EDX, and Raman spectroscopy. The results showed that the phases of products are mainly composed of MgAl2O4 and carbon. The prepared MgAl2O4 has granular and rod-like morphologies, and the free carbon (1.172 wt%) exists between particles of MgAl2O4. Moreover, the addition of FeC2O4 as catalyst in raw materials ratio would be beneficial for improving crystallization of in situ carbon generated in the products. The oxidation activation energy of the prepared C/MgAl2O4 composite powders was calculated as 143.01 kJ/mol which was 22.17% higher than that of carbon black/MgAl2O4 powders (117.06 kJ/mol), suggesting that the C/MgAl2O4 composite powders prepared by combustion synthesis have excellent oxidation resistance. 相似文献
5.
Siyao Li Shoulei Xu Xiangyu Wang Daini Wang Bernard A. Goodman Xing Hong Wen Deng 《Ceramics International》2021,47(3):3346-3353
Cubic zirconia single crystals stabilized with yttria and doped with Gd2O3 (0.10–5.00 mol%) were prepared by the optical floating zone method, and characterized by a combination of X-ray diffraction (XRD), and Raman, electron paramagnetic resonance (EPR), ultraviolet–visible (UV–Vis), photoluminescence excitation (PLE) and photoluminescence (PL) spectroscopic techniques. XRD and Raman spectroscopy showed that the crystal samples were all in the cubic phase, whereas the ceramic sample consisted of a mixture of monoclinic and cubic phases. The absorption spectrum showed four peaks at 245, 273, 308, and 314 nm in the ultraviolet region, and the optical band gap differed between samples with ≤3.00 mol% and those with >3.00 mol% Gd2O3. The emission spectrum showed a weak peak at 308 nm and a strong peak at 314 nm, which are attributed to the 6P5/2 → 8S7/2 and 6P7/2 → 8S7/2 transitions of Gd3+, respectively. The intensities of the peaks in the excitation and emission spectra increased with Gd3+ concentration, reached a maximum at 2.00 mol%, then decreased with higher concentrations. This quenching is considered to be the result of the electric dipole-dipole interactions, and this interpretation is supported by the Gd3+ EPR spectra, which showed progressive broadening with increasing Gd3+ concentration throughout the concentration range investigated. 相似文献
6.
7.
Zhenying Chen Fei Li Xiaowei Chen Shoulei Xu DingKang Xiong YuYang Huang Wen Deng 《Journal of Materials Science: Materials in Electronics》2017,28(6):4654-4660
Thin films of Ti-doped ZnO (TZO) were prepared by RF magnetron sputtering using targets prepared with sintering temperatures in the range 1100–1500 °C; the microstructures and optoelectronic properties of the TZO targets and films were characterized by SEM, XRD, Hall Effect analysis, UV–VIS spectrophotometry and physical property measurement system. Results indicated that the target sintering temperature affected both the TZO targets and films. The Ti/Zn atomic ratios in the targets decreased progressively with increasing sintering temperature, but by a smaller amount in films prepared from them. XRD patterns showed that all films were preferentially oriented along the c axis at 2θ ~ 34° in their XRD patterns. The films sputtered with targets sintered at above 1300 °C were relatively smooth, and had larger average grain size. The target sintered at 1450 °C had the highest density. The best optoelectronic properties were found with the film sputtered from the target sintered at 1300 °C; this sample had superior crystal properties, high average optical transmittance (88.9%), and the lowest resistivity (8.47 × 10?4 Ω cm). Furthermore, the resistivity of all the films changed with temperature between 10 and 350 K, they experienced an initial decrease followed by an increase as the temperature was raised. 相似文献
8.
考虑具有端部附加质量的柔性附件及其和舱体的耦合效应,本文系统地推导出了一个带柔性附件的航天器热颤振准则,并用有限元程序进行了模拟校验.该准则揭示了柔性附件和舱体的质量特性和系统热诱发振动稳定性之间的关系.当舱体的质量特性远大于柔性附件的质量特性时,该准则就退化为悬臂柔性附件的热颤振准则. 相似文献
9.
Preparation of calcium aluminate cement by combustion synthesis and application for corundum‐based castables
下载免费PDF全文
![点击此处可从《International Journal of Applied Ceramic Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shoulei Yang Guoqing Xiao Donghai Ding Yun Ren Lihua Lv Pan Yang 《International Journal of Applied Ceramic Technology》2018,15(3):678-688
Calcium aluminate cement was prepared by combustion synthesis with CaO2, Al, and Al2O3 as raw materials. The effects of CaO/Al2O3 (C/A) molar ratios in raw materials on the phase compositions and morphologies of calcium aluminate were investigated in detail. It was found that when the C/A reduced from 1.1 to 0.74, the content of CaO·2Al2O3 (CA2) in products increased, whereas contents of CaO·Al2O3 (CA) and 12CaO·7Al2O3 (C12A7) decreased; when the C/A was 0.8, the phase composition of product (CS71) was equal to that of Secar71. Additionally, the crystallines of CA and CA2 in the product were reduced when the C/A molar ratio was decreased. And then, the bulk density, apparent porosity, permanent linear change, cold crushing strength (CCS), and cold modulus of rupture (CMOR) of the corundum‐based castables bonded with CS71, Secar7 were compared. The castables bonded with CS71 demonstrate obviously improved CCS, CMOR, and volume stability. 相似文献
10.