全文获取类型
收费全文 | 61篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 18篇 |
金属工艺 | 7篇 |
能源动力 | 3篇 |
轻工业 | 1篇 |
无线电 | 2篇 |
一般工业技术 | 26篇 |
冶金工业 | 3篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2003年 | 1篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有62条查询结果,搜索用时 62 毫秒
1.
The effects of seed layers on the characteristics of rf-sputtered lead zirconium titanate thin films were investigated. Prior to sputtering, PbTiO 3 seed layers (100 nm) were deposited onto the Pt/Ti/Si and Pt/Si substrates by sol-gel (spin coating) processing method. Structure-property relation was studied as functions of substrate temperature and sputtering conditions. Special efforts were given in optimizing the deposition parameters to prepare the films in the perovskite phase without post deposition annealing. Dielectric constant and loss tangent of the films were in the range 800-950 and 0.04 -0.06, respectively. Remanent polarization and coercive field were 23.1 w C/cm 2 and 75kV/cm, respectively, for the films without PbTiO 3 seed layer, where as the corresponding quantities for in situ -deposited perovskite Pb(Zr, Ti)O 3 films on PbTiO 3 seed layer were 28 w C/cm 2 and 65 kV/cm, respectively. 相似文献
2.
Reji John Larry P. Zawada Joseph L. Kroupa 《Journal of the American Ceramic Society》1999,82(1):161-168
Ceramic-matrix composites (CMCs) are being considered as replacement materials for divergent flaps and seals in advanced aerospace turbine engines. During service, these components are subjected to severe temperature gradients across the width of the flaps. This paper discusses an analytical procedure to estimate the stresses generated in the CMC flaps due to the temperature gradients. The analytical procedure can be used for a material with nonlinear temperature-dependent stress–strain behavior. This procedure was used to predict the thermal stresses in four candidate CMC systems due to temperature gradients. The thermal stresses along the edges typically exceed the proportional limit, and sometimes the fatigue limit of the CMC. 相似文献
3.
Pramod Kumar Hegde A. Vasudeva Adhikari M. G. Manjunatha C. S. Suchand Sandeep Reji Philip 《应用聚合物科学杂志》2010,117(5):2641-2650
Three new donor–acceptor type poly{2,2l‐(3,4‐ dialkoxythiophene‐2,5‐diyl)bis[5‐(2‐thienyl)‐1,3,4‐oxadiazole]}s ( P1, P2, and P3 ) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. The polymerization was carried out using chemical polymerization technique. The optical and charge‐transporting properties of the polymers were investigated by UV‐visible, fluorescence emission spectroscopic and cyclic voltammetric studies. The polymers showed bluish‐green fluorescence in solutions. The electrochemical band gaps were determined to be 2.03, 2.09, and 2.17 eV for P1 , P2, and P3, respectively. The nonlinear optical properties of new polymers were investigated at 532 nm using single beam Z‐scan and degenerate four‐wave mixing (DFWM) techniques with nanosecond laser pulses. The polymers exhibited strong optical limiting behavior due to “effective” three‐photon absorption. Values of the effective three‐photon absorption ( 3PA ) coefficients, third‐order nonlinear susceptibilities (χ(3)), and figures (F) of merit were calculated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
4.
Patrick J. Golden Ashley Whitney‐Rawls Sushant K. Jha W. John Porter III Dennis Buchanan Kartik Prasad Vivek Chandravanshi Vikas Kumar Reji John 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(3):674-685
The objective of this work was to develop and demonstrate a probabilistic life prediction method for the prediction of minimum fatigue lives that are typically used in the design of fracture critical rotating turbine engine components. A Monte Carlo analysis was used to predict the variability in fatigue lives based on the distribution of microstructural features that lead to early crack initiation as well as the variability in small fatigue crack growth rates. Two titanium alloys, both with bimodal microstructures, were tested and analysed in this study. The distribution of critical microstructural features was calibrated based on test results and understanding of microstructure neighbourhood effects. Testing was conducted on both alloys and included both smooth and notched specimens. The predictions are presented and compared with the data for smooth and notch geometries for the various loading conditions. A parametric study was performed to identify the importance of several model inputs and to identify areas for future improvement. 相似文献
5.
AbstractEnsuring uniform addition of coloring material to the fabric is an essential requirement in the textile dyeing process. Beam dyeing machine consists of a special beam, the barrel of which is evenly perforated with holes. The dye liquor is forced into the fabric material through this beam. For uniform fabric coloring, an equal distribution of the dye liquor through the porous beam has to be ensured. The present methodology employs theoretical and computational fluid dynamics aspects of beam dyeing process to obtain better performance. The analysis of a beam with a single row of branches shows that nonuniformity increases with an increase in inlet mass flow. Further beam flow distribution with and without fabric are studied for different parameters, such as branch diameter, inlet mass flow rate, operating conditions, and flow reversal. The present results provide guidelines to improve the levelness of the dye distribution in the fabric material. 相似文献
6.
Pramod Kumar Hegde A.V. Adhikari M.G. Manjunatha C.S. Suchand Sandeep Reji Philip 《Synthetic Metals》2009
A new donor–acceptor type poly{2,2′-(3,4-didodecyloxythiophene-2,5-diyl)bis[5-(2-thienyl)-1,3,4-oxadiazole]} (P) was synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. The polymerization was carried out using chemical polymerization technique. The optical and charge-transporting property of the copolymer was investigated by UV–vis, fluorescence emission spectroscopic and cyclic voltammetric studies. The copolymer shows UV absorption maxima at 375 nm and displays bluish-green fluorescence in DMF solution. Its electrochemical band gap was determined to be 2.07 eV. The nonlinear optical (NLO) properties of the copolymer was investigated at 532 nm using single beam Z-scan and degenerate four-wave mixing (DFWM) techniques with nanosecond laser pulses. The copolymer exhibits strong optical limiting behavior due to effective three-photon absorption (3PA). Values of the effective 3PA coefficient (γ), third-order nonlinear susceptibility (χ(3)) and figure of merit (F) have been calculated. 相似文献
7.
M. G. Manjunatha Airody Vasudeva Adhikari Pramod Kumar Hegde C. S. Suchand Sandeep Reji Philip 《Journal of Materials Science》2009,44(22):6069-6077
A new donor–acceptor type poly{2-(3,4-didecyloxythiophen-2-yl)-5-[3,4-diphenyl-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazole}
(P1) has been designed and synthesized starting from thiodiglycolic acid, 1,2-diphenylethane-1,2-dione, and diethyl oxalate through
multi-step reactions using precursor polyhydrazide route. The charge-transporting and linear optical property of the polymer
has been investigated by cyclic voltammetric, UV–visible, and fluorescence emission spectroscopic studies. The UV–visible
absorption spectrum of polymer in thin film form showed maxima at 420 nm. The polymer displayed bluish-green fluorescence
both in solution and thin film form. The optical band gap is determined to be 2.27 eV. Third-order nonlinear optical property
of the new polymer has been investigated at 532 nm using single beam Z-scan and degenerate four wave mixing (DFWM) techniques
with nanosecond laser pulses. The absorptive nonlinearity observed for the polymer P1 is of optical limiting type, which arises due to an “effective” three-photon absorption (3PA) process. The third-order nonlinear
optical susceptibility (χ(3)) of the polymer is found to be 0.831 × 10–12 esu. Both linear and nonlinear optical studies revealed that the new polymer (P1) is a promising material for applications in photonic devices. 相似文献
8.
Ryan J. Morrissey Reji John W. John Porter III 《International Journal of Fatigue》2009,31(11-12):1758
In order to develop more accurate life prediction tools, an improved understanding of the variability within the fatigue behavior of a material is required. Recent work has shown multiple failure mechanisms that drive the variability in fatigue life of polycrystalline titanium and nickel materials. In addition, the bimodal behavior in the fatigue response is not readily apparent when only a very small number of specimens are tested at each loading condition, as is normal practice.The objective of this work was to investigate the fatigue variability of a single crystal nickel-base superalloy at elevated temperature. PWA1484, a second generation single crystal alloy developed for advanced turbine airfoil applications, was the material of choice for this investigation. A large number of fatigue tests were performed at one condition (stress level, stress ratio, frequency and temperature) to determine the variability and identify the sources of uncertainty in life. Scanning electron microscopy was used to investigate the relationship between failure mechanisms and variability. Crack growth analyses were used to predict lowest life estimates and were compared to experimental data. The results show large variability in fatigue life at fairly high stresses. Evaluation of the fracture surfaces indicated that microstructural features such as carbides and eutectics were responsible for the failures. In addition, the size of the feature responsible for fatigue failure could not be directly related to the fatigue life. The lowest expected life based on fatigue crack growth analyses did agree with the shortest life found experimentally. However, more testing and analysis is required. 相似文献
9.
Enhanced Ultrafast Nonlinear Optical Response in Ferrite Core/Shell Nanostructures with Excellent Optical Limiting Performance 下载免费PDF全文
Alberto López‐Ortega Gaurav Kumar Tiwari Josep Nogués Tamio Endo Reji Philip 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(6)
Nonlinear optical nanostructured materials are gaining increased interest as optical limiters for various applications, although many of them suffer from reduced efficiencies at high‐light fluences due to photoinduced deterioration. The nonlinear optical properties of ferrite core/shell nanoparticles showing their robustness for ultrafast optical limiting applications are reported. At 100 fs ultrashort laser pulses the effective two‐photon absorption (2PA) coefficient shows a nonmonotonic dependence on the shell thickness, with a maximum value obtained for thin shells. In view of the local electric field confinement, this indicates that core/shell is an advantageous morphology to improve the nonlinear optical parameters, exhibiting excellent optical limiting performance with effective 2PA coefficients in the range of 10?12 cm W?1 (100 fs excitation), and optical limiting threshold fluences in the range of 1.7 J cm?2. These values are comparable to or better than most of the recently reported optical limiting materials. The quality of the open aperture Z‐scan data recorded from repeat measurements at intensities as high as 35 TW cm?2, indicates their considerably high optical damage thresholds in a toluene dispersion, ensuring their robustness in practical applications. Thus, the high photostability combined with the remarkable nonlinear optical properties makes these nanoparticles excellent candidates for ultrafast optical limiting applications. 相似文献
10.
K Sasikumar G Suresh KA Thomas Reji John V Natarajan T Mukundan RMR Vishnubhatla 《Bulletin of Materials Science》2006,29(6):637-640
Magnetically active elastomer materials were prepared by incorporating nickel powder in synthetic elastomeric matrices, polychloroprene
and nitrile rubber. Cure characteristics, mechanical, electrical and magnetic properties were experimentally determined for
different volume fractions of magnetoactive filler. The cure time decreases sharply for initial filler loading and the decrease
is marginal for additional loading of filler. The tensile strength and modulus at 100% strain was found to increase with increase
in the volume fraction of nickel due to reinforcement action. The magnetic impedance and a.c. conductivity are found to increase
with increase in volume fraction of nickel as well as frequency. 相似文献