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1.
Structures of grain boundaries and triple line junctions in nanocrystalline materials are of interest owing to large fractions
of atoms in nanocrystalline materials being at these interfacial positions. Grain boundary and triple line junction structures
in nanocrystalline palladium have been studied using high-resolution transmission electron microscopy (HRTEM). The main micro
structural features observed include the varying atomic structures of grain boundaries and the presence of disordered regions
at triple line junctions. Also, there is variation in lattice parameters in different nanocrystalline grains. Geometric phase
analysis is used to quantify atomic displacements within nanocrystalline grains. Displacement fields thus detected indicate
links to the interface structures. 相似文献
2.
The thermal expansion of a titanium modified, swelling resistant austenitic stainless steel designated as D9 is studied by measuring the lattice parameter as a function of temperature in the range 300-1300 K by high-temperature X-ray diffraction technique. The thermal expansion data thus obtained is in reasonable agreement with the typical thermal expansion values reported for similar nuclear grade austenitic stainless steels. However, at temperatures exceeding 900 K, the measured thermal expansivity exhibits a pronounced non-linear increase due partly to the precipitation of complex carbide and intermetallic phases. The high-temperature thermal expansion data obtained in the present study are augmented by modelling the low-temperature thermal expansion behaviour by Grüneisen formalism. 相似文献
3.
Reena Rao S. Divakar Belur R. Lokesh 《Journal of the American Oil Chemists' Society》2002,79(6):555-560
The preference of lipase (EC 3.1.1.3) from Rhizomucor miehei in the incorporation of 11 FA, ranging from C10∶0 to C22∶6, into coconut oil TAG during acidolysis was studied by applying
the Plackett-Burman experimental design. Enzymatic acidolysis reactions were carried out in hexane at 37°C for 48 h with coconut
oil (0.1 M) and a mixture of 11 FA at a TAG to FA molar ratio of 1∶1. Lipase was used at the 5 wt% level. The incorporation
of FA into coconut oil TAG was determined by GC. The lipase showed preference for long-chain saturated FA for incorporation
into coconut oil TAG. The FA with 18 carbon atoms showed a high incorporation rate (18∶1>18∶1>18∶3). The lipase showed the
least preference for the incorporation of 12∶0, which occurs in maximal concentration (46%), whereas the most preferred FA,
18∶0, occurs at a very low concentration (<2%) in coconut oil. The overall preference of lipase for the incorporation of different
FA into coconut oil TAG was 18∶0>18∶2, 22∶0>18∶1, 18∶3, 14∶0, 20∶4, 22∶6>16∶0>12∶0≫10∶0. 相似文献
4.
Naresh Vankamamidi S. Allavarpu V. V. L. Divakar Reddi Sivaranjani 《The Journal of supercomputing》2022,78(6):8708-8732
The Journal of Supercomputing - The contemporary Group Key Agreement (GKA) entails lightweight computing, reduced communication, decentralized certification, personal privacy protection,... 相似文献
5.
Magnetic resonance image denoising using nonlocal maximum likelihood paradigm in DCT‐framework 下载免费PDF全文
P. Krishna Kumar P. Darshan Sheethal Kumar Rahul Ravindra Jeny Rajan Luca Saba Jasjit S. Suri 《International journal of imaging systems and technology》2015,25(3):256-264
The data acquired by magnetic resonance (MR) imaging system are inherently degraded by noise that has its origin in the thermal Brownian motion of electrons. Denoising can enhance the quality (by improving the SNR) of the acquired MR image, which is important for both visual analysis and other post processing operations. Recent works on maximum likelihood (ML) based denoising shows that ML methods are very effective in denoising MR images and has an edge over the other state‐of‐the‐art methods for MRI denoising. Among the ML based approaches, the Nonlocal maximum likelihood (NLML) method is commonly used. In the conventional NLML method, the samples for the ML estimation of the unknown true pixel are chosen in a nonlocal fashion based on the intensity similarity of the pixel neighborhoods. Euclidean distance is generally used to measure this similarity. It has been recently shown that computing similarity measure is more robust in discrete cosine transform (DCT) subspace, compared with Euclidean image subspace. Motivated by this observation, we integrated DCT into NLML to produce an improved MRI filtration process. Other than improving the SNR, the time complexity of the conventional NLML can also be significantly reduced through the proposed approach. On synthetic MR brain image, an average improvement of 5% in PSNR and 86%reduction in execution time is achieved with a search window size of 91 × 91 after incorporating the improvements in the existing NLML method. On an experimental kiwi fruit image an improvement of 10% in PSNR is achieved. We did experiments on both simulated and real data sets to validate and to demonstrate the effectiveness of the proposed method. © 2015 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 25, 256–264, 2015 相似文献
6.
Sangram K. Rath Vinod K. Aswal Chandan Sharma Kapil Joshi Manoranjan Patri G. Harikrishnan Devang V. Khakhar 《Polymer》2014
The objective of the present work is to get insights into the mechanistic origin of the reinforcement effects of nanoclay on a segmented polybutadiene polyurethane-urea system. To this end, a convergent analysis of the hard domain morphology and conformational state of soft segment in the nanocomposites was carried out by using a combination of complementary characterization techniques, namely, Fourier transform infrared spectroscopy, small angle neutron scattering, transmission electron microscopy, modulated differential scanning calorimetry and dynamic mechanical analysis. Analysis of small angle neutron scattering data by a combination of Percus–Yevick hard sphere and Zernike-Ornstein model coupled with direct visualization of the dispersed hard domain morphology from transmission electron microscopy provided insight on clay induced changes in the hard domain morphology. A monotonic decrease in the domain size as well as the average interdomain distance was observed with increasing nanoclay content in the polymer matrix. Analysis of the carbonyl stretching region from FTIR showed increased degree of hydrogen bonding for the urethane carbonyl groups of the nanocomposites compared to the neat matrix. A combination of calorimetric and dynamic mechanical analysis revealed the existence of a constrained amorphous region; quantified to be ≈ 16% at the highest clay content experimented. The manifestation of these morphological and conformational changes on the nano-, micro- and macro scale reinforcements in the nanocomposites was investigated by mechanical properties at these length scales using nanoindentation, DMA and tensile testing, respectively. 相似文献
7.
13CP/MAS NMR spectroscopic studies of some starches from cereals (wheat, maize and finger millet), pulses (green gram, chick pea), tuber (potato) and root (tapioca), and their respective acid (HCI, HNO3) modified starches were carried out. While cereal starches exhibited a triplet signal for their anomeric carbons, pulse, tuber and root starches showed doublets. Line width changes in signals indicated that debranching in the above modified starches led to narrowing of C6 signals (more pronounced in the case of potato and tapioca starches) and were consistent with the release of branching strains. Potato starch, both native and modified, was found to be different from other starches as inferred from the chemical shift values for their anomeric carbons and line shape. The dihedral angle (ϕ′2) calculated from chemical shift values for C1 and conformation of dihedral angel (x) as predicted from chemical shift of C6 are discussed with respect to structural organization. 相似文献
8.
Somashekar BR Lohith K Manohar B Divakar S 《Journal of Bioscience and Bioengineering》2007,103(2):122-128
A detailed kinetic study of the esterification of D-glucose with L-alanine catalyzed by lipases from Rhizomucor miehei (RML) and Candida rugosa (CRL) showed that both lipases follow the Ping-Pong Bi-Bi mechanism, in which L-alanine and D-glucose bind in subsequent steps releasing water and L-alanyl-D-glucose, with competitive substrate inhibition by D-glucose at higher concentrations leading to the formation of dead-end lipase.D-glucose complexes. An attempt to obtain the best fit of this kinetic model through curve fitting yielded good approximates of the apparent values of four important kinetic parameters: for RML-k(cat)=0.29+/-0.028x10(-3) M h(-1) mg(-1), K(m L-alanine)= 4.9+/-0.51x10(-3) M, K(m D-glucose)=0.21+/-0.018x10(-3) M, and K(i D-glucose)=1.76+/-0.19x10(-3) M; for CRL-k(cat)= 0.75+/-0.08x10(-3) M h(-1) mg(-1), K(m L-alanine)=56.2+/-5.7x10(-3) M, K(m D-glucose)=16.2+/-1.8x10(-3) M, and K(i D-glucose) =21.0+/-1.9x10(-3) M. 相似文献
9.
Barium lanthanum hafnium oxide, a complex perovskite ceramic, has been synthesized as nanoparticles by a modified combustion process for the first time. The Ba, La, and Hf ions required for the formation of Ba2LaHfO5.5 were obtained in solution by dissolving in boiling nitric acid a stoichiometric mixture of BaCO3, La2O3, and HfO2 that had been heated at 1200 degrees C for 4 h. By complexing the ions with citric acid and using ammonia as fuel, it was possible to get Ba2LaHfO5.5 as nanoparticles in a single-step combustion process. The powder obtained by the present combustion process was characterized by X-ray diffraction, BET surface area analysis, differential thermal analysis, thermogravimetric analysis, infrared spectroscopy, and scanning and high-resolution transmission electron microscopy. According to the results of X-ray and electron diffraction, the powder synthesized through the combustion process showed single-phase barium lanthanum hafnium oxide. The transmission electron microscopic investigations showed a grain size of 42 nm, with a standard deviation of 8 nm. The nanoparticles of Ba2LaHfO5.5 synthesized by the present combustion technique could be sintered to > 97% of the theoretical density at a relatively low temperature of 1425 degrees C. Scanning electron microscopic studies on the sintered Ba2LaHfO5.5 samples showed that the final grain size of the sintered specimen was < 500 nm. 相似文献
10.
Divakar Rajamani Dr Gajendra Kumar Adil 《The International Journal of Advanced Manufacturing Technology》1998,14(4):298-305
Scheduling and sequencing compounds on banbury mixers is a daily production planning function in a tyre company. The current scheduling procedures are based on experience. A number of factors, such as, capacity, cost, time, speed, set-up of mixers, compound changeovers, density and demand of compound, have to be considered during planning. In this paper, we propose a two-stage approach to this problem. This approach can be easily computerised to aid the personnel in the planning function. An example, considering actual data obtained from the company, is used to illustrate the approach. The current scheduling practice by company personnel, as inferred from past record, is also reported. 相似文献