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1.
The aim of this study was to evaluate the use of ground-based canopy reflectance measurements to detect changes in physiology and structure of vegetation in response to experimental warming and drought treatment at six European shrublands located along a North-South climatic gradient. We measured canopy reflectance, effective green leaf area index (green LAIe) and chlorophyll fluorescence of dominant species. The treatment effects on green LAIe varied among sites. We calculated three reflectance indices: photochemical reflectance index PRI [531 nm; 570 nm], normalized difference vegetation index NDVI680 [780 nm; 680 nm] using red spectral region, and NDVI570 [780 nm; 570 nm] using the same green spectral region as PRI. All three reflectance indices were significantly related to green LAIe and were able to detect changes in shrubland vegetation among treatments. In general warming treatment increased PRI and drought treatment reduced NDVI values. The significant treatment effect on photochemical efficiency of plants detected with PRI could not be detected by fluorescence measurements. However, we found canopy level measured PRI to be very sensitive to soil reflectance properties especially in vegetation areas with low green LAIe. As both soil reflectance and LAI varied between northern and southern sites it is problematic to draw universal conclusions of climate-derived changes in all vegetation types based merely on PRI measurements. We propose that canopy level PRI measurements can be more useful in areas of dense vegetation and dark soils.  相似文献   
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In the present study, a novel method of measuring the uptake of nutrients by 1H NMR spectroscopy was performed to determine dietary effects. Six pigs catheterized in the portal vein and mesenteric artery were fed breads made from whole-wheat grain (WWG), wheat aleurone flour (WAF; 19?% aleurone of bread) or rye aleurone flour (RAF; 15?% aleurone of bread) in a repeated 3?×?3 crossover design. Three meals were provided daily (at 0, 5 and 10?h), and each period comprised of 1?week. Portal and arterial blood samples were collected at fasting (?30?min) on day 4–7, and on day 7, pooled blood samples were collected at 0–2.5, 2.5–5, 5–7.5 and 7.5–10?h after first (0?h) daily meal. Using the arterial-venous difference and ANOVA–simultaneous component analysis, plasma betaine was found to accumulate during the experimental period. On day 7, plasma betaine concentrations was 20–40?% higher than when feeding the WAF diet compared with RAF and WWG (P?=?0.001), whereas the content of betaine in the WAF diet was about twice as high. The arterial-venous difference showed a tendency (P?=?0.078) for the diet–time interaction of betaine absorption in the absorption phases but there was no diet effect (P?=?0.31), which indicates a steady-state absorption has been reached on day 7. Furthermore, high plasma betaine levels correlated with low plasma creatine of endogenous origin. In conclusion, the explorative method revealed that the plasma concentration and absorption of betaine were differentially modified by the diets.  相似文献   
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The manufacturing of composite structures is accompanied by fabrication induced deformations. Those deformations are undesirable and lead to transgression of geometric tolerances in the finished parts. In order to get the part within aspired dimensional tolerances, geometrical compensation of the tool is necessary. This often iterative conducted tooling-rework is commonly time consuming and costly. This paper presents an shell element based. semi-analytical simulation approach focusing on warpage deformations due to tool part interaction, in order to account for manufacturing induced deformations within the tool design process. Deviation measurements on test specimen level serve as inputs for the calculation of equivalent coefficients of thermal expansion according to the proposed analytical model. Thus, ‘warpage properties’ of different prepreg – tool–material combinations are determined. The use and the practicability of the developed approach is demonstrated by means of the calculation of a warpage compensated tool surface.  相似文献   
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Content and composition of brain gangliosides were compared among endothermic mammals, heterothermic hibernators and ectothermic fishes from habitats with extreme ambient temperatures (tropic vs. antarctic waters). In general the content of brain gangliosides in fishes is significantly lower and exhibits a greater variability than in mammals. The composition of brain gangliosides was investigated using both one- and two-dimensional High Performance Thin Layer Chromatography (HPTLC). Both techniques showed a remarkable increase in the number of individual ganglioside fractions and an additional increase of higher polar fractions in fishes as compared with mammals. The 2D-HPTLC revealed a significant decrease in the relative proportion of alkali-labile gangliosides in the course of evolution from fish to mammals. Moreover this decrease in alkali-lability is correlated with the state of thermal adaptation (antarctic fishes, 53-66%; tropical cichlid fish, 35%). These results provide additional evidence for the notion that the extremely high polarity of brain gangliosides, especially of cold-blooded vertebrates, reflects a very efficient mechanism on the molecular level to keep the neuronal membrane functional under low temperature conditions.  相似文献   
6.
Proposes a novel method for the characterisation of parasitic optical feedback by measuring the diode laser linewidth change with injection current. Results were obtained with a MCRW (metal-clad ridge-waveguide) laser and reflections from an optical isolator. A feedback signal 67 dB below the laser output was definitely measured.<>  相似文献   
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Software and Systems Modeling - Software models are the core development artifact in model-based engineering (MBE). The MBE paradigm promotes the use of software models to describe structure and...  相似文献   
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Electronic commerce (e-commerce) and mobile commerce (m-commerce) have dramatically boosted the demand for services which enable ubiquitous access. Ubiquity offers opportunities in terms of time aware, location aware, device aware, and personalised services. Development of ubiquitous Web applications, however, turns out to be rather complex and thus requires appropriate methodological support. Existing methods for modelling Web applications only partially match the requirements resulting from their ubiquitous nature.This article aims at filling this gap by presenting a UML based framework for modelling ubiquitous Web applications, focussing on issues of adaptation modelling. It encompasses both, context modelling by providing a physical and a logical context model, and modelling the adaptation process per se. The latter is realised in terms of a rule model enabling monitoring of context changes and activation of corresponding adaptation operations. The separation of a Web application in a stable and context independent part on the one hand and a variable and context dependent part on the other hand supports reusability and locality of change.  相似文献   
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In a postal questionnaire investigation of experiences and attitudes concerning end-of-life decisions among Danish physicians, most of the respondents reported having made decisions involving the hastening of a patient's death, and considered this acceptable. Such decisions were more frequent, and were considered ethically more acceptable, when made with the patient's informed consent than without. Of the respondents, two per cent had participated in assisted suicide, and five per cent had administered a lethal injection at the patient's request, practices considered ethically acceptable by 37 per cent and 34 per cent, respectively, of the respondents. The most frequently cited reasons for opposing such practices were double effect principle, the active killing/allowed-death distinction, and the sanctity of life; and the most frequently cited justifications were respect for the patient's autonomy, the avoidance of unnecessary suffering, and the patient's right to a death with dignity.  相似文献   
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