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71.
Oxygen transmission rates (OTR) of two multilayer films containing ethylene vinyl alcohol (EVOH) were analyzed after water absorption at 121 °C. The films, referred to as film A and film B, were laminated film of PET/EVOH/PP and coextruded film of PET/PP/nylon 6/EVOH/nylon 6/PP, respectively. OTR increased with water absorption for both films. Graphical representation of data revealed two apparent linear regions describing the change of OTR with water absorption for both films. At low water contents (up to 4%) OTR were similar for the two films but differed dramatically at higher water contents. Water sorption characteristics of two monolayer EVOH barrier films (biaxially oriented and non-oriented) were determined at 25 °C using standard gravimetric method. Moisture sorption isotherms were analyzed using the Guggenheim-Anderson-de Boer model and the cluster theory of Zimm and Lundberg to evaluate the interactions between water and EVOH.  相似文献   
72.
Characterization of water-soluble extracts from hot-pressed poplar   总被引:1,自引:0,他引:1  
Thermal modification of wood constituents occurs upon hot-pressing of flakes during consolidation of oriented strand board (OSB). Hence, the effects of hot-pressing of hybrid poplar on water-soluble extractives were studied. Poplar veneers were pre-conditioned to 0 or 8 % moisture content and subsequently hot-pressed at 150, 200 or 250 °C. Aqueous extracts were characterized by conventional chemical methods in conjunction with chromatography (HPLC and SEC), mass spectrometry (ESI–MS) and spectroscopy (FTIR) analysis. Water-soluble fractions were markedly influenced by thermal compression treatment at 250 °C compared to the lower temperatures. Chromatographic results indicate that water-soluble extractives content increases with temperature while the degree of polymerization decreases with detection at low temperature levels. FTIR spectroscopic analysis indicates changes in aqueous-extracts composition of wood monosaccharides (hemicelluloses), meanwhile ESI–MS detected xylo-oligosaccharides. These results clearly show that heat treatment dictated the changes in each water-soluble extractive component and they respond independently with different treatment.  相似文献   
73.
At Siemens Corporate Research we have created a set of tools for the analysis of MR and CT cardiovascular images in the applications Argus, Vessel View, and Proteus. Argus is designed to assess cardiovascular function by reporting measures of morphology and tissue health using a 2-D approach. Vessel View, a 3-D application, is capable of quantifying vascular integrity and provides tools for segmenting vessels. Lastly, Proteus has functionality for registering 3-D cardiac data sets (e.g., MR and CT). Taken together, these applications allow for a comprehensive analysis of MR and CT cardiovascular studies. Throughout this paper we will illustrate the capabilities of our tools via their application to an actual clinical case. Our contribution lies in combining several computer vision technologies and applying them to practical, real world problems.  相似文献   
74.
Reviews the book, The Blackwell handbook of early childhood development edited by Kathleen McCartney and Deborah Phillips (see record 2006-04286-000). This book can serve as a useful guide for advanced undergraduate students to approach child development research at a deeper level than that of a typical textbook. Although some chapters lack sufficient depth for the advanced psychology graduate student, a large portion of the handbook will provide the novice reader with the opportunity to get acquainted with current issues in the science of early child development, and may introduce the intermediate reader to useful background knowledge in unfamiliar fields of interest. The chapters in this handbook series as a whole also serve as a highly useful source of information for lecture preparations for faculty teaching outside their core area of concentration. Chapters are consistently brief, clear, and well written. Overall, this book offers a valuable intermediary reading option between the simplicity of a standard textbook and the detailed accounts of books on specific developmental spheres. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
75.
Registration and modeling of shapes are two important problems in computer vision and pattern recognition. Despite enormous progress made over the past decade, these problems are still open. In this paper, we advance the state of the art in both directions. First we consider an efficient registration method that aims to recover a one-to-one correspondence between shapes and introduce measures of uncertainties driven from the data which explain the local support of the recovered transformations. To this end, a free form deformation is used to describe the deformation model. The transformation is combined with an objective function defined in the space of implicit functions used to represent shapes. Once the registration parameters have been recovered, we introduce a novel technique for model building and statistical interpretation of the training examples based on a variable bandwidth kernel approach. The support on the kernels varies spatially and is determined according to the uncertainties of the registration process. Such a technique introduces the ability to account for potential registration errors in the model. Hand-written character recognition and knowledge-based object extraction in medical images are examples of applications that demonstrate the potentials of the proposed framework.  相似文献   
76.
Cognition, Technology & Work - One objective of Industry 4.0 is to reach a better system performance as well as to have a better consideration of humans. This would be done by benefiting from...  相似文献   
77.
Cognition, Technology & Work - Since the start of industrialization, machine capabilities have increased in such a way that human control of processes has evolved from simple (with...  相似文献   
78.
Rotational wood-dowel welding has been shown to rapidly produce wood joints of considerable strength without any adhesive. The technique offers an opportunity to increase productivity and reduce costs in the furniture industry. The objective of the study was to define optimal wood-dowel welding parameters for two North American hardwood species frequently used for indoor appearance products: sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis). Optimized parameters for individually studied species were determined using a rotational wood-dowel welding machine designed for the technique. A comparative analysis of wood-dowel welding parameters was performed. The investigated parameters for both species were grain orientation, rotational speed, and insertion speed. Temperature profile measurements at the interface during rotational wood-dowel welding were also carried out. Optimal welding mechanical properties were determined from the dowel withdrawal strength using a standard tensile strength test. Results revealed a significant interaction between species, rotational speed, and insertion speed. Sugar maple produced wood joints with higher withdrawal strength than yellow birch. The best results for sugar maple and yellow birch were obtained with a rotational speed of 1000?rpm. A 25?mm?s?1 insertion speed produced significantly stronger welded joints in sugar maple than at 12.5?mm?s?1. For yellow birch, a 16.7?mm?s?1 insertion speed provided the best results. Both species and rotational speed had a significant effect on peak temperature at the interface during welding. Peak welding temperatures with optimal parameters were 244 and 282?°C for sugar maple and yellow birch, respectively.  相似文献   
79.
We present here a simple and versatile variant of the thermal analysis of soot carbon, and a discussion on the encountered analytical artifacts. The method is based on a two-step combustion procedure; the removal of the organic material that does not absorb visible light is optimized during a precombustion step at 340°C during 2 hours under a pure oxygen flow, and the remaining carbon is then determined by coulometric titration of the CO2 evolved from the combustion of the samples. These analytical conditions minimize the crossover between the different components of the aerosol, but better to a clear-cut division between organics and soot carbon, the quantitative evaluation of their thermal evolution is obtained. Artifacts have been tested thoroughly with various standards and replicates of ambient air samples collected. The method gives reliable soot carbon determination at the microgram level in samples from a wide variety of environments. Combined H / C atomic ratio measurements and investigations of the problems associated with the thermal determination of soot carbon permit gaining some insight on the nature of carbonaceous aerosols. They reinforce the indication that soot carbon is not composed primarily of elemental carbon. Also, it is suggested that highly polymerized natural organic aerosols though different in nature could behave thermally and optically like soot.  相似文献   
80.
Background: DNA methylation is an epigenetic control mechanism that may be altered by environmental exposures. We have previously reported that in utero exposure to the mycotoxin and liver carcinogen aflatoxin B1 from the maternal diet, as measured using biomarkers in the mothers’ blood, was associated with differential DNA methylation in white blood cells of 6-month-old infants from The Gambia. Methods: Here we examined aflatoxin B1-associated differential DNA methylation in white blood cells of 24-month-old children from the same population (n = 244), in relation to the child’s dietary exposure assessed using aflatoxin albumin biomarkers in blood samples collected at 6, 12 and 18 months of age. HM450 BeadChip arrays were used to assess DNA methylation, with data compared to aflatoxin albumin adduct levels using two approaches; a continuous model comparing aflatoxin adducts measured in samples collected at 18 months to DNA methylation at 24 months, and a categorical time-dose model that took into account aflatoxin adduct levels at 6, 12 and 18 months, for comparison to DNA methylation at 24 months. Results: Geometric mean (95% confidence intervals) for aflatoxin albumin levels were 3.78 (3.29, 4.34) at 6 months, 25.1 (21.67, 29.13) at 12 months and 49.48 (43.34, 56.49) at 18 months of age. A number of differentially methylated CpG positions and regions were associated with aflatoxin exposure, some of which affected gene expression. Pathway analysis highlighted effects on genes involved with with inflammatory, signalling and growth pathways. Conclusions: This study provides further evidence that exposure to aflatoxin in early childhood may impact on DNA methylation.  相似文献   
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