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71.
Wilfried H. Eppendorfer 《Journal of the science of food and agriculture》1977,28(7):607-614
In experiments with increasing applications of nitrogen to ryegrass, red clover and lucerne grown in pots, freeze-dried plant material with widely varying N-content was obtained. Increasing N-concentrations were associated with increasing nitrate contents which proportionally decreased the concentrations (g/16 g total-N) of all amino acids. Expressed as g amino acid/16 g total-N minus NO3-N, concentrations of all amino acids were closely similar at different N-levels. Differences between the three species ' amino acid composition were negligible except for a lower concentration of lysine in the crude protein of ryegrass and of methionine + cystine in the crude protein of clover and lucerne. In feeding experiments with rats increasing total-N concentrations were generally associated with higher true digestibilities of the crude protein of ryegrass, red clover and lucerne, but slightly lower biological values, especially in red clover. Net crude protein utilisation was increased by increasing total-N concentration in ryegrass, decreased in red clover and unchanged in lucerne. When ranked according to the nutritional value of the crude protein, ryegrass comes first, lucerne second and red clover last. Addition of synthetic methionine to ryegrass and lucerne improved their biological values by 30 and 47% respectively. 相似文献
72.
Wilfried H. Eppendorfer 《Journal of the science of food and agriculture》1977,28(2):152-156
In experiments with increasing applications of nitrogen to oats and rye grown in pots, grain with widely varying N-content was obtained. In rye increasing N-concentrations were associated with decreases in the protein of lysine and several other amino acids including threonine, tryptophan, methionine and cystine, whereas glutamic acid, proline and phenylalanine increased. In oat protein the amino acid composition was less affected by increasing N-content in grain. Concentrations of most essential amino acids were higher in oat than in rye protein, especially at high N-levels. The ratio lysine + arginine/proline was higher in oat than in rye protein and did not, as in rye, decrease with increasing N-concentration. Lysine as a percentage of dry matter increased up to the highest N-level in both cereals. In rat feeding experiments true digestibility of the protein of oats and rye increased to the same extent with increasing N-concentration in grain, whereas the biological value of the protein decreased considerably in rye but only slightly in oats. Net protein utilisation decreased with increasing N-content in rye but increased in oats. 相似文献
73.
The sulfuric acid catalysed absorption and reaction of isobutene was studied in a bubble column (10.2 cm diameter, 256 cm height) covering a wide range of liquid phase compositions. At acid concentrations of 40–48% wt and tert-butanol concentrations of 3.2–4.3 moles/l. the absorption rate has a maximum value. From measurements in the slow reaction or diffusional regime of mass transfer it was possible to obtain a value of liquid side mass transfer coefficient kL. As interfacial areas and solubilities of isobutene were determined by independent means the rate constants of the hydration could be evaluated from this and other studies in bubble column reactors. The reaction rate constant follows a simple correlation which considers the effect of the acid and the generated butanol. Thus, all relevant data of the absorption-reaction system are available. The significance of these data was checked by a dynamic study in a smaller bubble column. 相似文献
74.
J. E. Yu K. S. Jones P. H. Holloway B. Pathangey E. Bretschneider T. J. Anderson S. S. Sun C. N. King 《Journal of Electronic Materials》1994,23(3):299-305
A temperature and flow modulation (TFM) technique has been developed to modulate the manganese doping profile in ZnS phosphor
material grown by lowpressure metalorganic chemical vapor deposition for alternating-current thin film electroluminescent
devices (TFELDs). In the TFM technique, modulation of both the substrate temperature as well as the flows of metalorganic
sources, diethylzinc and tricarbonyl-(methylcyclopentadienyl)-manganese (TCPMn), was used to grow a structure consisting of
alternating layers of undoped ZnS at 400°C and Mn-doped ZnS where Mn being incorporated into the undoped ZnS at 550°C. X-ray
results indicated that MnSx phases were present within the ZnS host crystal matrix for the modulation doped samples, while a MnxZn1-xS solid solution was present in the uniformly doped samples. The luminescence efficiency of the TFELDs could be modified by
growing the phosphor with dopant (luminescent center) modulation. The TFELDs with a single modulated doping phosphor layer
showed lower threshold voltages in the range 70 to 80 V with light emission in the 580 to 587 nm wavelength range. With a
twofold increase in the total thickness of the undoped ZnS layer, the brightness and the luminescence efficiency, measured
at the threshold voltage plus 40 V, increased by a factor of 20 and 10, respectively. The electroluminescent (EL) characteristics
of the phosphors with multiple dopant layers showed higher luminescence efficiency. By using the TFM growth technique, one
can engineer the luminescent center distribution in the phosphor layer to improve the EL characteristics. 相似文献
75.
Wilfried Pestemer und Werner Mannt 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1980,171(4):272-277
Zusammenfassung Die Rückstandssituation von 14 herbiciden Wirkstoffen (Alachlor, Chloridazon, Chlorpropham, Chloroxuron, Chlorthal-methyl, Desmetryn, Lenacil, Linuron, Methabenzthiazuron, Monolinuron, Napropamid, Pendimethalin, Phenmedipham und Terbutryn) in 6 Küchenkräutern (Borretsch, Dill, Kerbel, Kresse, Pimpinelle und Sauerampfer) wird erläutert anhand von Rückstandsdaten aus Freilandversuchen (2 Vegetationsperioden), die in zwei Laboratorien ermittelt wurden. Die Methoden werden schematisch beschrieben sowie Bestimmungsgrenzen und Wiederfindungsraten für beide Laboratorien angegeben.
Herbicide residues in some herbs
Summary Residue occurrence is discussed with use of 14 herbicides (Alachlor, Chloridazone, Chlorpropham, Chloroxuron, Chlorthal-methyl, Desmetryne, Lenacil, Linuron, Methabenzthiazuron, Monolinuron, Napropamide, Pendimethalin, Phenmedipham and Terbutryne) on 6 herbs (borage, dill, garden-chervil, garden cress, anise and sorrel) in the light of residue analyses (from field trials over two seasons with analyses carried out in two laboratories). The methods are outlined; limits of the determinations and recoveries are given.相似文献
76.
Versuche und Rechnungen zur Ankoppelung von Ultraschall an heiße, metallische Prüfstücke durch Wasser. Ermittlung der höchsten, eine Ultraschallübertragung durch Wasser noch zulassenden Oberflächentemperatur. Ankoppelungszeiten in Abhängigkeit von Wasserdurchfluß, Wassertemperatur und Oberflächentemperatur. Beschreibung eines wirksamen Kühlverfahrens zur schnellen Ankoppelung an bewegte Prüfstücke bei hohen Temperaturen. Anwendung auf Stranggußknüppel mit einer Oberflächentemperatur von 1250 °C bei einer Prüfgeschwindigkeit von 3 m/min. Rißempfindlichkcit verschiedener Stähle gegenüber rascher Abkühlung. 相似文献
77.
78.
de Boer AR Alcaide-Hidalgo JM Krabbe JG Kolkman J van Emde Boas CN Niessen WM Lingeman H Irth H 《Analytical chemistry》2005,77(24):7894-7900
The potential of high-temperature liquid chromatography (HTLC) was investigated in an on-line combination with a screening system for bioactive compounds against the enzyme cathepsin B. Samples were separated by HTLC and subsequently analyzed by an on-line continuous-flow enzymatic assay. Detection was performed by electrospray ionization mass spectrometry, revealing both the bioactivity and the molecular mass of the bioactive compounds. Compared to conventional reversed-phase liquid chromatography, the amount of methanol necessary for separation could be decreased to only 10%, which improved the compatibility of LC with a biochemical assay. Sufficient preheating of the mobile phase prior to the separation and postcolumn cooling to prevent deactivation of the enzyme, even at column temperatures as high as 208 degrees C, was achieved as indicated by the reliable peak shapes obtained. The sensitivity was comparable with previously described systems operating at ambient temperatures as similar IC50 values were obtained. Exposing the inhibitors to high temperatures did not lead to thermal decomposition. The separation of inhibitors and the subsequent biochemical assay was performed either isothermally at various temperatures or by applying various temperature gradients as well as at various flow rates. The results obtained clearly show the compatibility of HTLC with an enzymatic screening assay. 相似文献
79.
80.
Marleen Morbee Antoni Roca Josep Prades-Nebot Aleksandra Pižurica Wilfried Philips 《Signal, Image and Video Processing》2008,2(2):129-140
In some video coding applications, it is desirable to reduce the complexity of the video encoder at the expense of a more
complex decoder. Wyner–Ziv (WZ) video coding is a new paradigm that aims to achieve this. To allocate a proper number of bits
to each frame, most WZ video coding algorithms use a feedback channel, which allows the decoder to request additional bits
when needed. However, due to these multiple bit requests, the complexity and the latency of WZ video decoders increase massively.
To overcome these problems, in this paper we propose a rate allocation (RA) algorithm for pixel-domain WZ video coders. This
algorithm estimates at the encoder the number of bits needed for the decoding of every frame while still keeping the encoder
complexity low. Experimental results show that, by using our RA algorithm, the number of bit requests over the feedback channel—and
hence, the decoder complexity and the latency—are significantly reduced. Meanwhile, a very near-to-optimal rate-distortion
performance is maintained.
This work has been partially supported by the Spanish Ministry of Education and Science and the European Commission (FEDER)
under grant TEC2005-07751-C02-01.
A. Pižurica is a postdoctoral research fellow of FWO, Flanders. 相似文献