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41.
Inhalation of radon and its daughter products is the major contributor to the total exposure of the population to natural radiation. An indoor radon survey has been carried out in the state of Chhattisgarh (80.26 degrees N to 84.41 degrees N and 17.8 degrees E to 24.1 degrees E), India under the national coordinated radon project of the Department of Atomic Energy. In the frame of this project indoor radon concentration has been measured in 105 dwellings situated in different villages of Chhattisgarh state. Houses were selected for measurements to cover the most common type of houses generally existing in the rural areas. Measurements have been done on quarterly integrating cycle for one full year in each dwelling using radon cup dosemeter employing LR-115, type-II (pelliculable), solid-state nuclear track detectors. The gamma radiation level was also checked in each dwelling using a gamma survey meter. It was found that the annual average indoor radon concentration in these dwellings varies from 9.91 to 87.84 Bq m(-3) with overall mean value of 26.48 Bq m(-3). Gamma level in these rural dwellings varies from 14.84 to 26.56 microR h(-1) with mean value of 18.68 microR h(-1). We observed that the radon concentration is relatively higher in the houses where the floor is bare but relatively lower in those houses where the floor is tiled or cemented.  相似文献   
42.
Food composition databases provide important data that can be used in a variety of ways to improve the nutritional quality of food and the health of the populations. The multicultural nature of European populations, together with increased travel and the globalisation of the food supply, has led to an increase in the consumption of ethnic foods by both mainstream and ethnic populations. However, the information that is available on the composition of ethnic foods is currently incomplete and fragmentary which both prevents effective health and disease interventions and limits the provision of dietary advice and information. One of the aims of the ethnic foods work package within the European Commission’s FP6 Network of Excellence EuroFIR is the provision of new and reliable data on the nutritional composition of ethnic foods from seven EU Member States and Israel for inclusion in national food composition databases. To achieve this goal, specific standards and mechanisms were developed to sample and analyse foods to harmonise procedures. Given the anticipated usage of the data it was essential that they were representative of the foods consumed in the country or region and that proper sampling procedures of the foods were employed. The most important nutrients were prioritised and analysed by selected accredited laboratories. The analytical methods selected were appropriate to fulfil the requirements of the resulting data. Quality assurance measures (ISO 17025, CRMs, IQC) were in place and the data accurately reflected the composition of chosen foods. This paper describes the procedures for producing validated new data for inclusion in forthcoming publications.  相似文献   
43.
The concrete industry is an important source of CO2 gas emissions. The cement used in the design of concrete is the result of a chemical process linked to the decarbonation of limestone conducted at high temperature and results in a significant release of carbon dioxide. Under the project EcoBéton (Green concrete) funded by the French National Research Agency (ANR), concrete mixtures have been designed with a low cement quantity, by replacing cement by mineral additions i.e., blast-furnace slag, fly ash or limestone fillers. Replacement of cement by other materials at high percentages generally lowers the early age strength of the resulting concrete. To cope with this problem, an optimisation method for mix design of concrete using Bolomey’s law has been used. Following the encouraging results obtained from mortar, a series of tests on concretes with various substitution percentages were carried out to validate the optimisation method.  相似文献   
44.
In order to have a better idea of the interaction of the defect centres produced by y-irradiation with dislocation in the processes of deformation destruction, mechanoluminescence (ML) and thermoluminescence (TL) of gamma-irradiated CaSO4:Dy, these phosphors have been investigated. CaSO4:Dy phosphors were prepared by dissolving CaSO4.2H2O in sulphuric acid and evaporating the excess acid around 300 degrees C. ML was excited impulsively by dropping a load on to the sample. Two peaks have been observed in the ML intensity against time curve. The total light output, i.e. integrated ML intensity, increases with concentration of dopant, strain rate and with irradiation doses. The TL glow curves of CaSO4:Dy phosphors at different concentrations of dopant and irradiation doses were also recorded. Studies of the influence of post-irradiation annealing on the ML of CaSO4:Dy show that with the removal of the TL dosemetric peak (approximately 210 degrees C) the ML intensity decreases markedly. A spectroscopic study of ML and TL has also been carried out to elucidate the mechanism of ML. Correlation between ML and TL has also been found.  相似文献   
45.
A novel technique is proposed for data hiding in digital audio that exploits the low sensitivity of the human auditory system to phase distortion. Inaudible but controlled phase changes are introduced in the host audio using a set of allpass filters (APFs) with distinct parameters of allpass filters, i.e., pole-zero locations. The APF parameters are chosen to encode the embedding information. During the detection phase, the power spectrum of the audio data is estimated in the z-plane away from the unit circle. The power spectrum is used to estimate APF pole locations, for information decoding. Experimental results show that the proposed data hiding scheme can effectively withstand standard data manipulation attacks. Moreover, the proposed scheme is shown to embed 5-8 times more data than the existing audio data hiding schemes while providing comparable perceptual performance and robustness  相似文献   
46.
In this paper, we propose a multi-level abstraction mechanism for capturing the spatial and temporal semantics associated with various objects in an input image or in a sequence of video frames. This abstraction can manifest itself effectively in conceptualizing events and views in multimedia data as perceived by individual users. The objective is to provide an efficient mechanism for handling content-based queries, with the minimum amount of processing performed on raw data during query evaluation. We introduce a multi-level architecture for video data management at different levels of abstraction. The architecture facilitates a multi-level indexing/searching mechanism. At the finest level of granularity, video data can be indexed based on mere appearance of objects and faces. For management of information at higher levels of abstractions, an object-oriented paradigm is proposed which is capable of supporting domain specific views.  相似文献   
47.
Calcium fluoride CaF2 is an interesting host lattice for rare earth (RE) activators. CaF2 crystals doped with different concentrations of Dy, Ce, Er and Gd have been grown by the Bridgman technique and their deformation luminescence (DL) induced by room temperature gamma irradiation has been recorded. When a uniaxial pressure is applied on to gamma-irradiated CaF2:RE crystals, initially the DL intensity increases with time, attains a maximum value and then it decreases with time. Although the DL intensity produced during the release of pressure is less, its rise and decay behaviours are similar to that obtained during the application of pressure. The DL intensity depends on dopant, concentration of dopant, irradiation doses and mass of the load or applied pressure. It is suggested that the moving dislocation produced during deformation of crystals capture holes from hole trapped centres (like perturbed Vk centre) and the subsequent radiative recombination of the dislocation holes with electrons give rise to DL.  相似文献   
48.
This paper presents results from a study on long-term deformations of concrete with a high content of mineral additions, such as blast-furnace slag and fly ash. Autogenous and drying shrinkage were monitored. The kinetics and magnitude of these deformations are modified by the type and content of mineral additions. This behaviour is mainly due to the slow advancement of their hydration reaction and to the evolution of their microstructure during the first days. Mechanical properties were also affected by mineral additions. All these modifications led to an increase in cracking susceptibility of concrete mixtures with blast-furnace slag. But their optimisation in terms of mechanical performance allowed reducing their cracking risk. An analytical model (Eurocode 2) was also applied for comparison. The prediction of the total shrinkage of the studied concrete mixtures was found to be satisfactory, but the autogenous shrinkage of concrete mixtures with mineral additions was significantly underestimated.  相似文献   
49.
With an increasing use of emerging patterning technologies such as UV-NIL in biotechnological applications there is at the same time a raising demand for new material for such applications. Here we present a PEG based precursor mixed with a photoinitiator to make it UV sensitive as a new material aimed at biotechnological applications. Using HSQ patterned quartz stamps we observed excellent pattern replication indicating good flow properties of the resist. We were able to obtain imprints with <20 nm residual layer. The PEG based resist has hydrogel properties and it swelling in water was observed by AFM.  相似文献   
50.
BackgroundA child with microspherophakia is described who was managed with scleral fixation of the loose capsular bag using Ahmed capsular tension segment and the small capsular bag was expanded using a standard capsular tension ring.MethodsThe child presented initially with lenticular myopia and concomitant glaucoma for which he was treated with peripheral iridotomy alone. The IOP remained uncontrolled after iridotomy procedure. Therefore, bimanual clear lens aspiration was performed; standard capsular tension ring was implanted ‘in the bag’ and Ahmed capsular tension segment was sutured to the sclera to stabilize the capsular complex. Foldable acrylic IOL was then injected into the bag.ResultsPostoperatively, the child had an unaided acuity of 20/30 on ETDRS. The IOL was centered well and the capsular bag had expanded due to the effect of CTR.ConclusionsThis ‘dual support’ technique takes advantage of using both CTR and CTS to overcome the generalized zonulopathy found in cases of microspherophakia. It effectively counteracts lenticular myopia, treats glaucoma, strengthens the capsular bag and does not entail the future risk of IOL-bag dislocation.  相似文献   
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