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排序方式: 共有198条查询结果,搜索用时 9 毫秒
1.
Experimental investigations have been carried out for spherical and non-spherical particles using beds comprised of single-sized particles and mixtures in the size and particle density ranges of 439 to 1524 μm and 1303 to 4948 kg/m3, respectively. Five conical fluidizers with varying apex angles of 8.86, 14.77, 19.60, 32.0 and 43.2 degrees were used. Experimental values of minimum velocity and bed pressure drop with air as the fluidizing medium have been compared with their respective values obtained from different models available in the literature. Deviations for each chosen model have been presented. 相似文献
2.
The effect of initial powder blend composition on the synthesis and formation mechanism of nickel silicide phases was investigated by mechanical alloying in Ni-60 and Ni-66.7?at.% Si powder blends. It was noted that the equilibrium NiSi phase started to form in the early stages of milling and that the amount of the NiSi phase in the milled powder increased with increasing milling time. Even though, under equilibrium conditions, a mixture of both the NiSi and NiSi2 phases was expected to be present in the Ni-60?at.% Si composition and the stoichiometric NiSi2 phase in the Ni-66.7?at.% Si composition, the NiSi phase was present in both the compositions investigated. However, while only the NiSi phase was present homogeneously in the Ni-60?at.% Si powder blend, both the NiSi phase and a very small amount of unreacted Si were present in the powder blend of Ni-66.7?at.% Si composition. This unexpected phase constitution in the milled powders was attributed to a partial loss of Si during mechanical alloying of the powder blends, confirmed by energy dispersive X-ray spectrometer analyses, and explained on a thermodynamic basis. 相似文献
3.
S. Narendra Babu A. Siddeshwar K. Srinivas S. V. Suryanarayana T. Bhimasankaram 《Journal of Materials Science》2009,44(15):3948-3951
A composite material when placed under the external magnetic/electric fields exhibits voltage/induced magnetization is known
as magnetoelectric (ME) composite. Such composite materials should have ferroelectric and ferro/ferri magnetic phases as constituents.
The magnetoelectric output is exhibited as a product property. Magnetoelectric composites are being used for variety of applications
including resonators, filters, phase shifters, optical isolators, actuators and magnetic field sensors. Metal/ferroelectric/metal
magnetoelectric composite using Ni and PZT as constituent phases has been fabricated in 2-2 composite pattern to study its
product property. The paper presents magnetoelectric studies of Ni/PZT/Ni composite using low dc magnetic field magnetoelectric
set-up. Using this ME set-up ME output of Ni/PZT/Ni composite is studied as a function of dc magnetic field. The results were
analyzed to identify the useful magnetic field (dc and ac) range in which Ni/PZT/Ni sensor can be utilized for applications. 相似文献
4.
T. P. Prasad A. Suryanarayana 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1973,23(10):711-715
Isothermal oxidation of ferrous sulphate heptahydrate in presence and absence of sodium carbonate has been carried out in the temperature range 205 to 265 °C. The oxidation proceeds in two steps. The rate constants for the oxidation at various temperatures have been calculated. The results indicate that the low temperature mechanism of oxidation proposed earlier does not hold good at higher temperatures. 相似文献
5.
Upadhyayula Suryanarayana Murty Mutheneni Srinivasa Rao Natarajan Arunachalam 《Applied Artificial Intelligence》2013,27(9):828-834
Japanese encephalitis (JE), a complex viral disease transmitted by mosquitoes. Determination of vector (mosquito) density is a prerequisite for devising effective control measures against this disease. Bayesian network is a widely used tool that has recently found application in the epidemiological surveillance studies. This article describes the application of Bayesian network tool to predict the Japanese encephalitis vector density using the longitudinal data collected from the Kurnool district of Andhra Pradesh, India, from 2001 to 2006. The entomological parameter from the study area indicates that various contributing factors are responsible for the prevalence of these vectors, making it difficult to estimate the importance of any particular parameter contributing to the increase of vector density. The application of this approach resulted in 73.12% to 95.12% accuracy compared to the test data with the corrected data. 相似文献
6.
G. Suryanarayana Reddy C. L. Narasimha Rao L. Venkataratnam P. V. Krishna Rao 《International journal of remote sensing》2013,34(17):3373-3380
Abstract. Spectral reflectance of leaves is influenced primarily by plant pigments, chlorophyll and carotenoids. Such reflectance can be used to study the changes in chlorophyll content and nitrogen status and in turn measures the amount of biomass accumulation. A field experiment was laid out at the Research Farm of ANGR Agricultural University, Hyderabad. The reflectance observations were taken using a hand-held ground radiometer at an interval of 15 days beginning from 30 days after sowing (DAS) until harvest of the crops. The plant pigments were determined simultaneously using DMSO (dimethyl sulphoxide) method in the laboratory. The experimental results revealed the influence of plant pigments on spectral reflectance of maize, groundnut and soybean. It was observed that there was an increase in chlorophyll- a, chlorophyll- b, total chlorophyll and carotenoid content up to flowering and thereafter chlorophyll- a content declined at a faster rate than chlorophyll- b towards physiological maturity. With the increase in concentrations of chlorophyll and carotenoids, there was a decline in spectral reflectance of the blue band (450-520 nm) and the red band (620-680 nm). Whereas, NIR (near-infrared) reflectance in the case of soybean and groundnut was found to be higher than that of maize by 11% and 2%, respectively. This was attributed to canopy cover of soybean and groundnut crops, where the soil was fully covered with vegetation. In case of maize, due to wider spacing, the soil exposure is greater, which results in low reflectance values of the NIR band. Normalized Difference Vegetation Index (NDVI) is linearly related to total chlorophyll content and the growth stages of a crop up to flowering. The NDVI differs significantly during the peak vegetative growth period among the three crop types. The study revealed that the significant differences in reflectance of maize, groundnut and soybean in the red and NIR bands were influenced by concentrations of chlorophyll- a, chlorophyll- b and carotenoids, which indicates the photosynthetic behaviour of the crops. 相似文献
7.
W. K. Wang H. Iwasaki C. Suryanarayana T. Masumoto N. Toyota T. Fukase F. Kogiku 《Journal of Materials Science》1982,17(5):1523-1532
Amorphous Nb-19 at% Si alloy, prepared by rapid quenching from the molten state, was annealed while being subjected to a pressure of 10 GPA. X-ray diffraction investigations on the alloy specimens quenched to ambient conditions have shown that pressure greatly alters the crystallization characteristics and the cubic A15 (Nb3Si)-phase forms in preference to the tetragonal Nb3Si-phase at temperatures in the range from 710° C to 800° C. Up to 680° C, the component atoms do not show any tendency towards ordering upon crystallization and the body-centred tetragonal solid solution forms; while, at 830° C, niobium atoms diffuse to form the body-centred cubic Nb precipitates. Superconducting properties have been measured for the single-phase A15 structure with the lattice parametera=0.5155 nm with the results that the transition temperature,T
C, is 3.4 K and the temperature coefficient of the upper critical field,H
C2, is 1.2 MA m–1 K–1 (15 kOe K–1). 相似文献
8.
F. H. Froes Ph.D. D. Eylon D.Sc. C. Suryanarayana Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1990,42(3):26-29
As the performance requirements of structures and devices increase, new and improved materials and processes are required. One such technique is thermochemical processing, which involves the use of hydrogen as a temporary alloying element. Thermochemical processing significantly enhances both the fabricability and mechanical behavior of titanium alloys. 相似文献
9.
10.
X-ray diffraction line profiles of five silver base ternary alloys in α-phase with varying atomic percentages of cadmium and
indium were recorded in both cold-worked and annealed states of the samples. Detailed studies on the profiles involving peak
shift, peak asymmetry and Fourier analysis of line shapes have been carried out to evaluate microstructural parameters such
as deformation fault probabilities,rms strains and dislocation densities. It was found that the addition of indium has a marked effect in producing deformation
fault probabilities in comparison to that of adding cadmium in ternary silver base alloys. Compound fault probability was
found to be maximum for the alloy Ag-10Cd-15In. 相似文献