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101.
Zusammenfassung Um der oft gehörten Meinung entgegenzutreten, die energetischen Wirkungsgrade lebender Organismen seien wesentlich höher als die technischer Verfahren, werden entsprechende Werte miteinander verglichen. Der sehr niedrige Wirkungsgrad der Photosynthese zusammen mit der kleinen Energiedichte der Sonnenstrahlung erzwang ab einer kritischen Größe die Aufspaltung in Energiesammler, die Pflanzen, und Verbraucher chemischer Energie, den Tieren. Dank den 10 mal höheren Wirkungsgraden in der Technik, lassen sich Solarmobile bauen, die von der auf sie fallenden Sonnenstrahlung angetrieben werden. Wegen des Multiplikationsgesetzes der Teilwirkungsgrade ergeben sich sowohl für die Speicherung der Sonnenenergie in den fossilen Brennstoffen wie in der Nahrungskette extrem niedrige Wirkungsgrade.
Herrn Prof. Dr.-Ing. U. Grigull zum 75. Geburtstag gewidmet 相似文献
Efficiencies in the world of life and in engineering
One often hears the opinion, that the efficiencies in the world of life are higher than in engineering. To disprove this, many values of efficiency of corresponding processes are compared. The very low efficiency of photosynthesis in living plants together with the low density of solar radiation has led the world of life to split into collectors of energy, the plants, and consumers of chemical energy, the animals. Thanks to the ten times higher efficiencies of solar cells, it is possible, to produce solar mobiles, vehicles that move driven by solar radiation.
Herrn Prof. Dr.-Ing. U. Grigull zum 75. Geburtstag gewidmet 相似文献
102.
Starting from Wheeler's composite theory, which takes both the multilayer adsorption and the capillary condensation into consideration, and assuming the equivalent cylindrical model, we have deduced a strict and relatively simpler formula for the calculation of pore size distribution by solving the integral equation directly. The formula is more convenient for application because of its recursion form. Following the same line of reasoning and using the mean value theorem of definite integrals under different conditions, we have unified the equations of Barrett-Joyner-Halenda, Dubinin, Cranston-Inkley, Dollimore-Heal and Roberts. A table of parameters which is required in the calculation is given. Besides the adsorption of nitrogen, the adsorption with water vapor as the adsorbate is investigated and the corresponding empirical equation of adsorption thickness is given. 相似文献
103.
Dr. F. C. Goodrich 《Colloid and polymer science》1967,219(2):156-159
Summary Under steady state conditions the reduction in the diffusive flux into a sphere due the presence of a neighboring, identical sphere is calculated. Taking the flux into a sphere as 1 when the particles are at infinite separation, the flux decreases to a minimum value of 0.693 when the spheres are touching.
With 2 figures 相似文献
Zusammenfassung Unter stationären Bedingungen wird die Abnahme des Diffusionsflusses in eine Kugel, bedingt durch eine benachbarte identische Kugel, berechnet.Wird der Diffusionsfluß in eine Kugel gleich 1 gesetzt, wenn die Partikel unendlich weit voneinander entfernt sind, so nimmt der Diffusionsfluß auf einen Minimalwert von 0,693 ab, wenn sich die Kugeln berühren.
With 2 figures 相似文献
104.
Dr. H. Demel Dipl.-Ing H. J. Grießer Prof. Dr. K. Hummel 《Colloid and polymer science》1977,255(11):1131-1132
Ohne ZusammenfassungMit 1 Abbildung und 1 Tabelle 相似文献
105.
Dr. Ulrich Mayer 《Monatshefte für Chemie / Chemical Monthly》1978,109(2):421-433
A model has been developed for calculating the enthalpy, entropy and free energy change associated with the creation of cavities in a liquid the size of which corresponds to the volume occupied by a solvent molecule. The molar enthalpy change H
cav equals the molar enthalpy of vaporization of the liquid, the free energy change G
cav is given by G
cav=–RT ln (V
m
·p
eq
/RT) (V
m
=molar volume,p
eq
=equilibrium vapor pressure) and is related to the standard free energy of vaporization. This relationship provides an estimate of the free energy of cavity formation required to accomodate a substrate in the liquid. It has been shown, that the free energy of solvation of a substrate can be dissected into different contributions accounting for (1) the concentration dependence of partial molar free energy quantities, (2) the formation of holes in the solvent, (3) the existence of specific, short range solute-solvent interactions and (4) the dielectric polarization of the medium. Application of this concept leads to an equation of the general form G
S
–G
R
=a(DN
S
–DN
R
)+b(AN
S
–AN
R
)+c(G
vp
oS
–G
vp
oR
), where G represents the free energy of reaction or activation,DN the donor number,AN the acceptor number and G
vp
o
the standard free energy of vaporization of a solventS and a reference solventR, resp.
Mit 3 Abbildungen 相似文献
Mit 3 Abbildungen 相似文献
106.
A R P?s? O A Forsander 《Acta chemica Scandinavica. Series B: Organic chemistry and biochemistry》1976,(9):801-806
The effect of the ethanol oxidation rate on the interaction between the phosphorylation state (the [ATP]/[ADP] X [HPO4]2- ratio) and the redox state (the free [NAD+]/[NADH] ratio) of the liver cytosol was studied in intact fed rats. The rate of ethanol oxidation was inhibited to different degrees with pyrazole. The ethanol oxidation rate had no influence on the liver lactate level but correlated significantly with the pyruvate level. Accordingly, a significant correlation was also found between the ethanol oxidation rate and the lactate/pyruvate ratio. The rate of ethanol oxidation correlated significantly with the liver 3-phosphoglycerate level. No change in the glyceraldehyde-3-phosphate level was found. No correlation was found between the ethanol oxidation rate and the glyceraldehyde-3-phosphate/3-phosphoglycerate redox couple. Ethanol administration slightly increased the liver ATP level, but the simultaneous administration of pyrazole eliminated this effect. Other adenine nucleotides and HPO4 2- were not changed. The changes in the rate of ethanol oxidation had no effect on the phosphorylation state in the fed liver. It is assumed that in the fed liver the phosphorylation state is so well stabilized that the redox level has no influence. 相似文献
107.
Song H Hecimovic S Goate A Hsu FF Bao S Vidavsky I Ramanadham S Turk J 《Journal of the American Society for Mass Spectrometry》2004,15(12):1780-1793
Dysregulation of proteolytic processing of the amyloid precursor protein (APP) contributes to the pathogenesis of Alzheimer's Disease, and the Group VIA phospholipase A(2) (iPLA(2)beta) is the dominant PLA(2) enzyme in the central nervous system and is subject to regulatory proteolytic processing. We have identified novel N-terminal variants of iPLA(2)beta and previously unrecognized proteolysis sites in APP constructs with a C-terminal 6-myc tag by automated identification of signature peptides in LC/MS/MS analyses of proteolytic digests. We have developed a Signature-Discovery (SD) program to characterize protein isoforms by identifying signature peptides that arise from proteolytic processing in vivo. This program analyzes MS/MS data from LC analyses of proteolytic digests of protein mixtures that can include incompletely resolved components in biological samples. This reduces requirements for purification and thereby minimizes artifactual modifications during sample processing. A new algorithm to generate the theoretical signature peptide set and to calculate similarity scores between predicted and observed mass spectra has been tested and optimized with model proteins. The program has been applied to the identification of variants of proteins of biological interest, including APP cleavage products and iPLA(2)beta, and such applications demonstrate the utility of this approach. 相似文献
108.
The application of NMR and MS methods for detection of adulteration of wine,fruit juices,and olive oil. A review 总被引:2,自引:0,他引:2
Ogrinc N Kosir IJ Spangenberg JE Kidric J 《Analytical and bioanalytical chemistry》2003,376(4):424-430
This review covers two important techniques, high resolution nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), used to characterize food products and detect possible adulteration of wine, fruit juices, and olive oil, all important products of the Mediterranean Basin. Emphasis is placed on the complementary use of SNIF-NMR (site-specific natural isotopic fractionation nuclear magnetic resonance) and IRMS (isotope-ratio mass spectrometry) in association with chemometric methods for detecting the adulteration. 相似文献
109.
Zusammenfassung Es wurden die Kristallitgröße und die Änderungen der parakristallinen Gitterstörungen aus den Linienbreiten des Röntgenweitwinkeldiagramms von lösungskristallisiertem linearem Polyäthylen bei den Temperaturen 15°K, 73°K, 173°K und Zimmertemperatur bestimmt. Es wurde eine Zunahme der Gitterstörungen mit fallender Temperatur gefunden.
Mit 3 Abbildungen
Vorgetragen auf der Arbeitssitzung des Fachausschusses Physik der Hochpolymeren in der Frühjahrstagung 1970 des Regionalverbandes Hessen-Mittelrhein-Saar der Deutschen Physikalischen Gesellschaft in Darmstadt, 10.–13. März 1970. 相似文献
Summary The crystallite size and the paracrystalline distortions in polyethylene single crystals were evaluated by the measurement of the linewidth in the X-ray wide angle diagram at four different temperatures (15°K, 73°K, 173°K and 297°K). An increase of the lattice distortions with decreasing temperature was found.
Mit 3 Abbildungen
Vorgetragen auf der Arbeitssitzung des Fachausschusses Physik der Hochpolymeren in der Frühjahrstagung 1970 des Regionalverbandes Hessen-Mittelrhein-Saar der Deutschen Physikalischen Gesellschaft in Darmstadt, 10.–13. März 1970. 相似文献
110.
Herwig G. Winkler Hagen T. Spath Prof. Dr. Karl Torkar 《Monatshefte für Chemie / Chemical Monthly》1975,106(2):535-545
The phase diagrams of the systems CsN3/Zn(N3)2 and KN3/Zn(N3)2 have been obtained employing the microscopic technique ofL. Kofler andA. Kofler. Within the system CsN3/Zn(N3)2 three eutectics at 148°C, 142°C, and 210°C were found. Besides Cs2Zn(N3)4, melting incongruently in the interval 153°C to 170°C, there exist two further compounds of the most probable composition Cs3Zn2(N3)7 and CsZn2(N3)5, melting congruently at 170°C and 210°C, resp. In the system KN3/Zn(N3)2 there exist two eutectics at 203°C and 172°C and two compounds, one of them, i.e. K2Zn(N3)4, melting congruently at 206°C, the other one, with composition KZn3(N3)7 or KZn4(N3)9, melting incongruently at 210°C.
Mit 8 Abbildungen
Herrn Professor Dr.Heribert Grubitsch zum 70. Geburtstag gewidmet. 相似文献
Mit 8 Abbildungen
Herrn Professor Dr.Heribert Grubitsch zum 70. Geburtstag gewidmet. 相似文献