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81.
Ceramic heat exchangers are increasingly used in many nuclear power plants. Silicon carbide has been treated as a promising material for heat exchanger application since it has good thermal conductivity and corrosion resistance. In this work, four different types of Si/SiC ceramic composites were prepared by liquid silicon infiltration technique. Thermal conductivities of these ceramic composites at different temperatures are measured by the laser flash thermal conductivity method. Results show that the presence of free carbon and voids are notably affecting the thermal conductivity of these materials. 相似文献
82.
Annakkage U.D. McLaren P.G. Dirks E. Jayasinghe R.P. Parker A.D. 《Power Delivery, IEEE Transactions on》2000,15(1):57-61
The hysteresis loop of the core material in a test current transformer is simulated using the Jiles-Atherton theory. Comparisons are made between recorded and simulated waveforms and it is found necessary to replace the modified Langevin function used by Jiles and Atherton. Using an alternative function described in the paper, good agreement is achieved between test and simulated waveforms 相似文献
83.
Mangosteen fruit pericarp is one of the important sources of bioactive compound xanthone. Supercritical carbon dioxide (SC-CO2) extraction was employed to extract xanthones from mangosteen fruit pericarp at three different levels of pressure (200–300 bar),
temperature (40–60 °C) and solvent to material ratio (100–300 kg/kg). The optimal conditions for the total xanthone yield
and the influence of parameters were determined by response surface methodology (RSM) using Box–Behnken design. In our study,
the increase in total xanthone yield in SC-CO2 fluid extraction depends more on the solute’s vapor effect. From response surface plots, pressure, temperature and solvent
to material ratio exhibited independent and interactive effects on the extraction of xanthones. A regression equation for
predicting the total xanthone yield was derived by statistical analysis, and a model with predictive ability of 0.99 was obtained.
Maximum xanthone yield of 8.01% was predicted by RSM at 60 °C, 300 bar and a solvent to material ratio of 300 kg/kg while
experimentally a yield of 7.56% was achieved. HPLC analysis was carried out for the optimum conditions for the identification
and quantification of the xanthones. The antioxidant activities of the extracts were investigated by ferric reducing antioxidant
power (FRAP) and the results showed that the extracts were enriched with antioxidant compound. 相似文献
84.
M.G. Shashidhar P. Giridhar K. Udaya Sankar B. Manohar 《Journal of Functional Foods》2013,5(3):1013-1030
Cordyceps sinensis (CS) is a well-known entamophagus fungus, naturally distributed in the Tibetan Plateau of Asia and Himalayas. Recently this synonym is transferred to Ophiocordyceps by both scientific and non-scientific communities. It is widely used as a tonic and medicinal food in traditional Chinese medicine (TCM), as it possess wonderful health benefits. To support its functional attributes, various investigations have been carried out to find out its adaptogenic, aphrodisiac, anti-oxidant, anti-aging, neuroprotective, nootropic, immunomodulatory, anti-cancer and hepatoprotective role. Its fruiting portion as well as the larvae possesses potent bio-active fractions and their composition almost found to be similar in both. The bioactive principles are nucleosides, exo-polysaccharides, sterols and, proteins, among others. Among nucleosides, adenosine and cordycepin are the major biochemical markers. Further, different types of solvent extracts and their mixtures exhibit wide range of pharmacological activities, while the water and methanol extracts with the richest sources of nucleosides and polysaccharides also show wide range of pharmacological activities. This review gives a panoramic view of potential health benefits of various classes of bio-active fractions along with the need for sustainable management of CS for human wellness. 相似文献
85.
K. J. Horadam P. Udaya 《Applicable Algebra in Engineering, Communication and Computing》2003,14(1):65-73
We present a new construction for p-ary codes meeting the Plotkin bound, for any odd prime p, from any planar function on the additive group of GF(p
a
). We use the Coulter-Matthews planar functions with p=3 to construct new families of ternary cocyclic codes, and compute their dimensions for a≤6.
Received: May 23, 2002; revised version: March 27, 2003
Keywords: Plotkin bound, Cocyclic code, Hadamard code, Planar function. 相似文献
86.
In the present study, we have identified pelargonidin 3-glucoside, along with two known anthocyanin; cyanidin 3-sophoroside and cyanidin 3-glucoside, from acidified, methanolic extract of mangosteen pericarp. The compounds were separated by preparative HPLC after purification by partition against ethyl acetate and Amberlite XAD-7. The structures of the compounds were confirmed by high performance liquid chromatography (HPLC), UV–Vis absorption spectra, high-resolution electrospray mass spectrometry and 1D, 2D nuclear magnetic resonance (NMR) spectroscopy. This new pigment family adds to the growing body of data supporting the use of natural colourants in food. Cyanidin 3-sophoroside was the major anthocyanin detected in large amount (76.1%), followed by cyanidin 3-glucoside (13.4%) and pelargonidin 3-glucoside (6.2%). 相似文献
87.
The field of biology is becoming increasingly interdisciplinary and cross-cutting. This changing research atmosphere is creating the way for a new kind of enquiry that while building upon the traditional research establishment is providing a new multidisciplinary framework to more effectively address scientific grand challenges. Using the US Department of Energy sponsored BioEnergy Science Center as an example, we highlight how impactful breakthroughs in biofuel science can be achieved within a large cross-disciplinary team environment. Such transformational insights are key to furthering our understanding and in generating models, theories and processes that can be used to overcome recalcitrance of biomass for sustainable biofuel production. Multidisciplinary approaches have an increasingly greater role to play in meeting rising demands for food, fibre, energy, clean environment and good health. Discoveries achieved by diverse minds and cross-applications of tools and analytical approaches have tremendous potential to fill existing knowledge gaps, clear roadblocks and facilitate translation of basic sciences discoveries as solutions towards addressing some of the most pressing global issues. 相似文献
88.
Polyacrylamide‐grafted‐sodium alginate copolymers were prepared by persulfate‐induced radical polymerization by using polymer‐to‐monomer ratios of 2 : 1 and 1 : 1. Polymers were characterized by Fourier transform infrared spectroscopy, differential thermal analysis, and viscosity. Membranes were prepared from the polymers, crosslinked with glutaraldehyde, and used in the pervaporation separation of water + isopropanol mixtures at 30°C. Equilibrium swelling experiments were performed for mixtures containing 10 to 80 mass % of water in the feed. Both the grafted copolymer membranes were ruptured while separating 10 mass % of water in the feed mixture. However, beyond 20 mass % of water in the feed mixture, flux increased with increasing grafting ratio, while selectivity decreased. Pervaporation separation experiments were carried out at 30, 40, and 50°C for 20 mass % of water in the feed mixture. By increasing the temperature, flux increased, whereas selectivity decreased. Arrhenius activation parameters for pervaporation and diffusion decreased with increasing grafting ratio of the membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2030–2037, 2004 相似文献
89.
Chiranjivi Jayaram Niraj Priyadarshi Jonnakuti Pavan Kumar Tata Venkata Sai Udaya Bhaskar Devendar Raju Ajith Joseph Kochuparampil 《International journal of remote sensing》2013,34(21):7506-7522
ABSTRACTThe chlorophyll-a concentration (chl-a), which is an index of phytoplankton pigment present in the oceans, is considered as a key indicator of health of marine ecosystems that could have direct effect on the human life. In this study, spatial and temporal variability of chl-a in the Arabian Sea (AS) is examined using reconstructed cloud-free ocean colour data for the period 2002–2015. Data Interpolating Empirical Orthogonal Function method is used to reconstruct the missing data. Subsequently, wavelet analysis is applied on the reconstructed data to assess the temporal variability in terms of seasonal, intra-seasonal, and interannual variability of chl-a in the AS. Wavelet analysis clearly depicted the low-frequency, stationary modes or approximation levels inferring the monthly, seasonal, and annual mean of the signal, while the high-frequency, non-stationary modes indicated the local abnormalities. From the analysis of gap-free data, the presence of biennial mode of variability in the northern AS chl-a is observed. The analysis further showed the existence of intra-seasonal oscillations in the northern AS during summer monsoon and single dominant peak during winter monsoon. Chl-a appeared to decline slightly during the entire study period across all the selected regions of the AS. Also, it is observed that chl-a in the northwestern region is highly dynamic than in the other regions of the AS. 相似文献
90.
Roopesh R Geedhika K Jason D'Souza S. Anandhan Udaya Bhat K Jaya M. J 《Journal of Experimental Nanoscience》2016,11(11):840-852
The present investigation reports the biogenesis of silver nanoparticles (Ag NPs) using extracts of a medicinal plant Nothapodytes foetida. Total phenolic content (TPC) and ferric reducing antioxidant power (FRAP) assay were carried out for the microwave-assisted extract (MAE) of N. foetida using methanol as solvent and the conditions for extraction were optimised by response surface methodology (RSM). The effects of operating variables such as extraction time, temperature and ratio of sample to solvent were studied using central composite design (CCD). A mathematical model with a high determination coefficient (R2) for TPC (0.991) and FRAP (0.995) was obtained. The optimal conditions of extraction for TPC were 48.6 ºC, 23.15 min and 2.04:30 (g/mL) and for FRAP 52.31ºC, 12.32 min and 1.67: 30 (g/mL). Under these conditions, the experimental yields of TPC and FRAP were 2.426 mg gallic acid equivalents (GAE)/g dry powder and 14.985mg of FeSO4·7H2O/g of dry powder, respectively. Ag NPs were characterised using UV–Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The synthesised Ag NPs have also shown potent activity against the human pathogenic Staphylococcus aureus. 相似文献