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1.
We assessed the use of 15N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary N excretion pattern at the ileum subsequent to the ingestion of a single 15N-labeled meal. In a second experiment, we compared ileal endogenous AA outputs and true AA digestibility estimates obtained in pigs ingesting 15N-labeled dietary proteins in a single meal vs. intravenous infusion of [15N]leucine for 10 d during the ingestion of a pea-based diet and a protein-free starch diet. The proportion of endogenous N found in the ileal digesta differed when the label was delivered orally (50%) vs. intravenously (72%) and changed with time. As a consequence, the true ileal AA digestibilities measured with labeled diets were lower. A third experiment demonstrated that this was due to the rapid recycling of labeled dietary N in endogenous moieties, because 15N was found in blood within 10 min of consuming the labeled meal, within 50 min of consumption in pancreatic enzymes, 90 min in bile and 4 h in ileal mucins. We conclude that the use of 15N-labeled meals for determination of true ileal AA digestibilities is limited by the fast recycling of dietary N in endogenous secretions following a single 15N-labeled meal. The accuracy of results will depend on meaningful estimates of AA flow during a limited period and accurate estimates of 15N in AA.  相似文献   
2.
Industry and plant breeders require fast methods to analyze glucosinolates in rapeseed. We tested the potential of near infrared reflectance spectroscopy (NIRS) for this analysis and developed calibration equations on a large population of whole seeds. Reference methods used are high performance liquid chromatography (HPLC) and gas liquid chromatography (GLC) of desulphoglucosinolates, a glucose-release method after purification on an anion exchange column and a palladium test. In the range from 2 to 107 μM/g and after transformation of the data in first derivative, a correlation coefficient of 0.99 was observed, as well as standard errors of estimated values of 2.15, 2.52, 2.67 and 4.07 for samples analyzed by HPLC, GLC, glucose and the palladium test, respectively. With different wavelengths, a limited calibration test on seeds containing from 4 to 40 μM/g gives a standard error of 1.91 μM/g (HPLC).  相似文献   
3.
BACKGROUND: The two‐phase partitioning bioreactor (TPPB) has become a new strategy for waste gas treatment. However, the impact of biomass and surfactants on gas/liquid (G/L) mass transfer needs to be better evaluated because the effects on the mass transfer coefficient KL and the interfacial area a, respectively, remains misunderstood. RESULTS: This study showed that, first, the surfactant extract produced by Rhodococcus erythropolis reduced the surface hydrophobicity of the biomass. Secondly, an optimal concentration appeared to exist for both components, respectively 0.5 g L?1 and 0.7 g L?1 for biomass (B) and surfactant extract (SE) when the global mass transfer coefficient (KLa) of oxygen was measured in a silicone oil/water TPPB. However, the combination of B and SE was found to induce a negative synergism. In particular, SE improved the interfacial area a by increasing the bubble diameter, while B reduced it as soon as a concentration of 1 g L?1 was exceeded. In contrast, the SE acted negatively on the KL, while B improved it overall. CONCLUSION: Better consideration is needed of the effect of biotic components in order to understand the phenomenon of G/L mass transfer in a TPPB. The behaviour of biomass growth and surfactants may strongly influence the mathematical models proposed in the literature. Copyright © 2009 Society of Chemical Industry  相似文献   
4.
Six varieties of isaño (Tropaeolum tuberosum), an Andean edible tuber, were analysed. The aim was to characterise qualitatively and quantitatively their content of glucosinolates and to determine concentration changes of these compounds upon delayed harvest. Additionally, exploratory assays were carried out on the effect of postharvest cold storage of the tubers as well as of a drying process imposed on blanched tuber slices. Only one glucosinolate (p‐methoxybenzyl glucosinolate) was found in the six domestic varieties analysed. Its concentration varied between 36.5 and 90.0 µmol g?1 dry matter. This range is relatively high when compared with other edible glucosinolate‐containing vegetables. ‘Dark’ coloured tuber varieties showed higher levels than ‘light’ coloured tuber varieties at normal harvest time. Of the two varieties on which the effect of delayed harvest was studied, one showed increasing and then decreasing changes until 44 days after maturity, while the other did not show any significant change with time. Postharvest cold stored samples showed similar changes to tubers kept in soil, and glucosinolate levels in dried blanched tubers did not differ significantly from those in fresh samples. Taken together, the data indicate that the glucosinolate content of isaño is highly dependent on both the variety and the time of harvest. These parameters should be taken into account when considering isaño as a promising food source with medicinal properties for humans and animals, but also with possible adverse biological effects, all related to the presence of glucosinolates. Copyright © 2004 Society of Chemical Industry  相似文献   
5.
Short chemical syntheses were developed to produce a new set of surfactants from uronic acids derived from widely available raw materials. Three different strategies were used to synthesize uronic amide derivatives, the structures of which were totally characterized by spectrometric methods (IR, MS, 1H-RMN and 13C-RMN). The best one, using an acid chloride as the synthetic intermediate, furnished the expected amides as a mixture of anomers in 46–58% global yield. Surface-active properties (CMC, γcmc, Γmax, A min) of homologous series of uronic acid N-alkylamides from C8 to C18 were also assessed. In general, these sugar-based surfactants exhibited good surface-activities, and appeared as valuable nonionic surfactants compared to octylphenol 9–10 ethylene oxide condensate, the most well-known nonionic surfactant. Increasing the alkyl chain length influenced the CMC values for both glucuronic and galacturonic N-alkylamide derivatives. The galacturonic N-alkylamides decreased γcmc at slower values than their counterpart’s glucuronic N-alkylamides.  相似文献   
6.
Bulletin of Engineering Geology and the Environment - This paper deals with the contribution of the ambient vibration horizontal-to-vertical spectral ratio (HVSR) method in soil engineering...  相似文献   
7.
Root volatile organic compounds (VOCs), their chemistry and ecological functions have garnered less attention than aboveground emitted plant VOCs. We report here on the identification of VOCs emitted by barley roots (Hordeum vulgare L.). Twenty nine VOCs were identified from isolated 21-d-old roots. The detection was dependent on the medium used for root cultivation. We identified 24 VOCs from 7-d-old roots when plants were cultivated on sterile Hoagland gelified medium, 33 when grown on sterile vermiculite, and 34 on non-sterile vermiculite. The major VOCs were fatty acid derived compounds, including hexanal, methyl hexanoate, (E)-hex-2-enal, 2-pentylfuran, pentan-1-ol, (Z)-2-(pentenyl)-furan, (Z)-pent-2-en-1-ol, hexan-1-ol, (Z)-hex-3-en-1-ol, (E)-hex-2-en-1-ol, oct-1-en-3-ol, 2-ethylhexan-1-ol (likely a contaminant), (E)-non-2-enal, octan-1-ol, (2E,6Z)-nona-2,6-dienal, methyl (E)-non-2-enoate, nonan-1-ol, (Z)-non-3-en-1-ol, (E)-non-2-en-1-ol, nona-3,6-dien-1-ol, and nona-2,6-dien-1-ol. In an olfactometer assay, wireworms (larvae of Agriotes sordidus Illiger, Coleoptera: Elateridae) were attracted to cues emanating from barley seedlings. We discuss the role of individual root volatiles or a blend of the root volatiles detected here and their interaction with CO2 for wireworm attraction.  相似文献   
8.
The noninvasive vascular laboratory is an important resource in the management of patients with peripheral vascular disease. The commonly accepted uses of the vascular laboratory, including both indirect testing (segmental limb pressures, waveform analysis, digital pressures, exercise testing, reactive hyperemia) and direct vascular testing with CDI, have been reviewed. These techniques have changed how these patients are diagnosed, with less need for invasive diagnostic techniques. Patient management and intervention have also been altered by these advances. The use of noninvasive techniques and continue progress in this area should continue to advance patient care.  相似文献   
9.
Three Brassicaceae species, Brassica napus (low glucosinolate content), Brassica nigra (including sinigrin), and Sinapis alba (including sinalbin) were used as host plants for two aphid species: the generalist Myzus persicae and the specialist Brevicoryne brassicae. Each combination of aphid species and prey host plant was used to feed the polyphagous ladybird beetle, Adalia bipunctata. Experiments with Brassicaceae species including different amounts and kinds of glucosinolates (GLS) showed increased ladybird larval mortality at higher GLS concentrations. When reared on plants with higher GLS concentrations, the specialist aphid, B. brassicae, was found to be more toxic than M. persicae. Identification of GLS and related degradation products, mainly isothiocyanates (ITC), was investigated in the first two trophic levels, plant and aphid species, by high-performance liquid chromatography and gas chromatography–mass spectrometry, respectively. While only GLS were detected in M. persicae on each Brassicaceae species, high amounts of ITC were identified in B. brassicae samples (allyl-ITC and benzyl-ITC from B. nigra and S. alba, respectively) from all host plants. Biological effects of allelochemicals from plants on predators through aphid prey are discussed in relation to aphid species to emphasize the role of the crop plant in integrated pest management in terms of biological control efficacy.  相似文献   
10.
Resume Au site de la gare souterraine Saint-Georges du future métro de Liège, les études géologiques, hydrogéologiques et géotechniques ont été réalisées conjointement avant l’établissement de l’avant-projet. Elles ont permis de déterminer la constitution détaillée de la plaine alluviale et du bed rock, l’hydrogéologie dans les alluvions et le terrain houiller, les propriétés géomécaniques des roches présentes et leur modification dans les massifs saturés en eau. La confrontation de toutes les données recueillies permet non seulement d’établir de meilleures corrélations entre les divers phénomènes examinés: nature, structure, texture des roches, allure et comportement des nappes aquifères, qualité des matériaux, … mais encore, par la synthèse, de fournir aux ingénieurs de projet une somme intéressante de renseignements quantitatifs propres au site investigué et à l’ensemble des conditions qui y règnent.
At the site of the underground station of the intended Metro of Liège the geological, hydrogeological and geotechnical investigations have been carried out jointly before the realization of the preliminary plan. They have enabled to determine the detailed geological constitution of the alluvial plain and of the bed-rock, the hydrogeology in the alluvial deposits and in the coal measures, the geomechanical properties of the rocks and their modifications in the massives saturated with water. The comparison of all the data gathered enables not only to obtain better correlations between the different phenomena investigated as nature, structure, texture of the rocks, aspect and behaviour of the underground water levels, quality of the materials, and so on, but also, through the synthesis, to supply the engineers of the plan with a useful amount of quantitative information which is peculiar to the site investigated and to the whole of the conditions existing in it.


Ingénieur civil des mines et ingénieur géologue — Professeur à l’Université de Liège.

Ingénieur civil des mines et ingénieur géologue — Premier assistant à l’Université de Liège.

Ingénieur civil des constructions — Assistant à l’Université de Liège

Ingénieur géologue.  相似文献   
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