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1.
Zoran ?ujovi? Radivoje Sreji? Dušan Vu?eli? Dragomir Vitorovi? Branimir Jovan?i?evi? 《Fuel》1995,74(12):1903-1909
A sample of kerogen from Aleksinac oil shale was examined by high-resolution solid-state 13C n.m.r. spectroscopy. The presence and relative proportions of kerogen structural units were estimated using a combination of NQS and T1C methods with a peak-synthesis technique applied to the 13C CP—MAS spectrum. Relaxation parameters from these experiments were used to estimate differences in relative ‘mobility’ of various structural units. The kerogen was found to be highly aliphatic and to contain 79% long-chain aliphatic plus alicyclic structures, as well as 9% aromatic structures. These findings are in good agreement with the characterization of the same kerogen from its oxidation products. 相似文献
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Giuliano Fontanella Daniele Basciotti Florian Dubisch Florian Judex Anita Preisler Christian Hettfleisch Vladimir Vukovic Tim Selke 《Building Simulation》2012,5(3):293-300
Recent advancements in the domain of modeling physical processes offer opportunities to use equation based modeling environments, such as Modelica, for the simulation of building heating, ventilation, and air-conditioning (HVAC) systems. The current work demonstrates Modelica capabilities in a case study of real building solar thermal system simulation. The simulated system is part of an innovative ENERGYbase building, designed according to the so called Passivhaus standard. Model calibration and validation procedure is developed to include optimization based parametric adjustments of component models using the monitoring data during a single week. The calibrated system adequately reproduces half a year of real system operation. Future work will concentrate on application of the developed calibration and validation methodology in the whole year overall building energy simulation. 相似文献
4.
An aerobic membrane bioreactor (MBR) at complete biomass retention was studied over a period of time under starvation conditions. Kinetic parameters were determined in a no‐feed batch test. The decay rate of activated sludge, kd = 0.05 d–1, was determined by tracking the decrease of MLSS. The ratio of MLVSS/MLSS was in the range 0.76–0.85. The pH values were between 7.02 and 8.23. As a function of different initial concentrations of MLSS, specific nitrification rates qN, decreased from 4.23 to 0.02 mg‐N/(g MLVSS d) and specific biodegradation rates qb increased from 0.23 to 1.90 mg‐COD/(g MLVSS d). From experimental data the kinetic constants for respiration, which followed Monod kinetics, were determined as qO2max = 9.8 mg‐O2/(g MLVSS h), Kx = 2.9 g/dm3. Additionally, a linear correlation between MLSS and mean floc size was found to exist during the biodegradation process. 相似文献
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Nevena Kaličanin Dr. Ana Marija Balaž Dr. Olivera Prodanović Prof. Dr. Radivoje Prodanović 《Chembiochem : a European journal of chemical biology》2023,24(20):e202300414
The aim of this research was to prove the function of the putative opine dehydrogenase from Desulfohalobium retbaense and to characterize the enzyme in terms of functional and kinetic parameters. A putative opine dehydrogenase was identified from a metagenomic library by a sequence-based technique search of the metagenomic library, and afterward was successfully heterologously produced in Escherichia coli. In order to examine its potential for applications in the synthesis of secondary amines, first the substrate specificity of the enzyme towards different amino donors and amino acceptors was determined. The highest affinity was observed towards small amino acids, preferentially L-alanine, and when it comes to α-keto acids, pyruvate proved to be a preferential amino acceptor. The highest activity was observed at pH 6.5 in the absence of salts. The enzyme showed remarkable stability in a wide range of experimental conditions, such as broad pH stability (from 6.0–11.0 after 30 min incubation in buffers at a certain pH), stability in the presence of NaCl up to 3.0 M for 24 h, it retained 80 % of the initial activity after 1 h incubation at 45 °C, and 65 % of the initial activity after 24 h incubation in 30 % dimethyl sulfoxide. 相似文献
7.
A series of imino and amino derivatives of 4-hydroxycoumarins were synthesised and evaluated for antioxidant potential, through different in vitro models such as (DPPH) free radical-scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. Also, antimicrobial activity of obtained coumarins was evaluated against 13 bacteria and eight fungi. All prepared compounds possessed good antioxidant activity and among them a p-nitrophenol derivative with IC50 at 25.9 μM possessed radical-scavenging activity which was comparable to BHT. Observed data for antibacterial activity indicated strong activity of all tested amino derivatives, while imines showed better antifungal properties. 相似文献
8.
Recently the FCC opened three 10 MHz bands for unlicensed use. In order to operate in UPCS bands, devices must comply with
rules known as the UPCS etiquette (United States Code of Federal Regulations, Title 47, Part 15(d)). In this paper we study
channel sharing between two or more collocated systems under the asynchronous UPCS etiquette. In particular we show that under
heavy load individual systems have a tendency to hold the channel for hundreds of milliseconds, thus blocking all traffic
in other, competing systems. We have calculated the distribution of the blocking time for two versions (or interpretations)
of the UPCS etiquette. The impact of the average blocking time on delay sensitive traffic is discussed and possible improvements
achieved through a tradeoff between system capacity and average blocking time are investigated.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
The use of optimization methods to automatically synthesize novel structures is attractive for optoelectronic design. However, the application of such methods to practical components is hindered by the long run times required to evaluate the performance of each particular trial design. This paper investigates, for the first time, how systematically adapting the accuracy of the simulations during the optimization process can be used to speed up the synthesis of effective designs. Adaptive accuracy variation is achieved in two ways: altering the acceptable error demanded of a particular simulation method and using a hierarchy of different methods. This novel method of synthesis is applied to quickly obtain optimal rib waveguide structures for two practical problems, namely modal degeneracy and low-loss fiber coupling. 相似文献
10.
Radivoje Vukovi Grozdana Bogdani Vjera Kureevi Vlasta Sria Frank E. Karasz William J. MacKnight 《应用聚合物科学杂志》1994,52(10):1499-1503
Miscibility in blends of random copolymers of p-bromostyrene (pBrSt) and o-bromostyrene (oBrSt) [P(pBrSt-co-oBrSt)] with partially sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) have been studied by differential scanning calorimetry (DSC). For an SPPO of given degree of sulfonylation, a miscibility window in terms of the isomeric composition of the brominated copolymer was seen; the location and width of the window was a function of sulfonylation. In general, copolymers with a higher content of pBrSt exhibit miscibility with SPPOs with higher degrees of sulfonylation. Upon annealing to temperatures of 280° and 320°C, only small changes in the miscibility regime were observed. The miscibility behavior was analyzed on the basis of the mean-field theory in terms of the individual segmental interaction parameters. © 1994 John Wiley & Sons, Inc. 相似文献