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EN
A new type collector α-Bromolauric acid (α-BLA) had been proved to be an efficient collector for quartz flotation. However, the effects of α-BLA on the flotation behavior of iron minerals and quartz-iron separation had not been investigated. In this study, collector α-BLA was synthesized in the laboratory. The flotation behavior of quartz, hematite and magnetite under α-BLA reverse flotation system were investigated and the separation mechanism of quartz-irons was studied by contact angle, zeta-potential and infrared spectroscopy. The results showed that the optimum flotation pH was 11.5 for quartz, 6.45 for hematite and 6.97 for magnetite. The best α-BLA concentrations was 75 mg/dm3 for quartz flotation, 125 mg/dm3 for hematite and magnetite flotation. The activator CaCl2 had little effect on the flotation of hematite and magnetite, but the minimum dosage 50 mg/dm3 of activator CaCl2 was necessary for quartz flotation. On the contrary, starch had no effect on the flotation of quartz, while the recoveries of magnetite and hematite tended to be 0% as starch concentration more than 80 mg/dm3. The separation mechanism of quartz from iron minerals under α-BLA reverse flotation system was that the starch could be selectively adsorbed on the surface of hematite and magnetite in the form of strong hydrogen bond adsorption. However, the same adsorption of starch did not occur on the surface of quartz, so the α-BLA can be successfully adsorbed on the surface of activated quartz to make the quartz strongly hydrophobic, and then to be floated out.
EN
The aim of the present study was to assess the physicochemical compatibility of a promising energetic salt, 5-amino-1H-tetrazole nitrate (5-ATN), with some typical materials. Thermal techniques (differential scanning calorimetry (DSC) and vacuum stability test (VST)) and non-thermal techniques (X-ray diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FTIR)) were applied. Five energetic materials (TNT, RDX, HMX, CL-20 and AP) and three common additives (Al, DOS and F2604-2) were tested to evaluate their compatibility with 5-ATN. Based on the DSC results, except for AP that was only partially compatible with 5-ATN, all of the selected materials exhibited good compatible with 5-ATN. The VST test further confirmed the compatibility of the 5-ATN/AP mixtures. Combined with the thermal methods, the FTIR results agreed with the DSC findings. The XRD results showed some differences.
EN
Independent component analysis (ICA) is usually used as a preliminary step for maternal electrocardiogram (ECG) QRS detection in fetal ECG extraction. When applying ICA to do this, a troublesome problem arises from how to automatically identify the separated maternal ECG component. In this paper we proposed a method called PRCH (short for Peak to peak entropy, R-R interval entropy, Correlation coefficient and Heart rate) for the automatic identifying. In the method, we defined four kinds of features, including amplitude, instantaneous heart rate, morphology and average heart rate, to characterize a signal, and determined some decision parameters through machine learning. Experiments and comparison with other three existed methods were given. Through taking metric F1 for evaluation, it showed that the proposed PRCH method has the highest identifying accuracy and generalization capability.
EN
The study pays attention to disturbances in early successional communities of wetland vegetation. We conducted artificial disturbances in a community of Suaeda salsa and Phragmites australis in the Yellow River Delta (China). Eight types of disturbances combining mowing treatments with species treatments were applied. Removal of the standing litters of P. australis or not was defined as mowing treatments, and removal of two species solo or both was defined as species treatments. We sampled 80 quadrats from the treatments plots at different intervals after the disturbance to investigate plant height, abundance, aboveground biomass, the distance between plants to reflect the effect of disturbance on composition, structure, productivity, and function of the plant communities. The strategies of seedling emergence and height growth differed as the canopy changed. Biomass contribution of different species, combined with disturbance intensity, was the main factors that affected the productivity. Homogeneity of disturbance was better for maintaining the functions of plant community in compared with the competitiveness (C), stress-tolerance (S) and ruderality (C-S-R) signatures with the control. Facilitations were reflected by the stagger arrangements in relative growth rates of the two species and in plant-plant interactions calculated by a modified function of competition. Adapting to symmetric disturbance and developing facilitative interactions are important requirements for early succession terrestrial vegetation to establish and stabilize in the seriously saline environments of wetlands.
5
EN
A novel kind of fluorescent DNA Probe based on fluorescence resonance energy transfer (FRET) was presented in this paper when CdTe/CdS/SiO2 core/multishell fluorescent nanoparticles were as energy donors and Au nanoparticles (AuNPs) were as energy acceptors. The DNA probes were prepared when energy donors and acceptors were conjugated with two single-stranded complementary oligonucleotides respectively and hybridized with each other. Compared with the fluorescent intensity of single-stranded DNA (ssDNA) conjugated CdTe/CdS/SiO2 nanoparticles (CdTe/CdS/SiO2-DNA), the fluorescent intensity of DNA probe was significantly increased and the FRET efficiency was about 71%. The detection results indicated that this novel DNA probe had excellent detection and specificity of completely complementary target ssDNA.
PL
W pracy zaprezentowano nowy rodzaj fluoryzującej próbki DNA opartej o rezonansowe przenoszenie energii fluoryzacji (FRET), gdzie donorami energii są nanocząstki CdTe/CdS/SiO2 z jądrową fluorescencją powłokową a akceptorami energii nanocząstki Au (AuNPs). W przygotowanych próbkach DNA energia donora i akceptora są odpowiednio sprzężone z dwoma pojedynczo skręconymi komplementarnymi oligonukleotydami i hybrydyzowane ze sobą. Intensywność fluorescencji próbki DNA ze sprzężonymi nanocząstkami CdTe/CdS/SiO2 (CdTe/CdS/SiO2 -DNA) w porównaniu z próbką pojedynczo-skręconego DNA (ssDNA) znacząco wzrasta, Wydajność FRET wynosi około 71%. Wyniki wykrywalności wykazują, że nowa próbka DNA ma doskonałą wykrywalność i swoistość do całkowicie komplementarnego docelowego ssDNA.
EN
In fluid mechanics, to obtain the multiple solutions in ordinary differential equations is always a concerned and difficult problem. In this paper, a novel RNA genetic algorithm (NRNA-GA) inspired by RNA molecular structure and operators is proposed to solve the parameter estimation problems of the multiple solutions in fluid mechanics. This algorithm has improved greatly in precision and the success rate. Multiple solutions can be found through changing accuracy and search coverage and multi-iterations of computer. At last, parameter estimation of the ordinary differential equations with multiple solutions is calculated. We found that the result has great accuracy and this method is practical.
PL
W artykule zaproponowano nowy algorytm genetyczny NRNA-GA inspirowany strukturą molekularną RNA przeznaczony do rozwiązywania równań z wieloma rozwiązaniami w mechanice cieczy.
7
Content available remote A New Multi-objective Optimization Algorithm: MOAFSA and its Application
EN
This paper proposes a multi-objective artificial fish swarm algorithm (MOAFSA), which imitates the behaviors of fish for local search, uses the quick sort method to get non-dominated solution set, and cuts the external set according to the crowding distance. This paper firstly uses MOAFSA for multi-objective functions test. Results show that MOAFSA has a faster convergence speed and the corresponding Pareto set is more evenly distributed; then MOAFSA is applied in the scheduling optimization of hydropower station reservoir.
PL
Przedstawiono nowy algorytm optymalizacyjny MOAFSA (multiobjective artificial fish swarm algorithm) bazujący na ławicy ryb. Algorytm sprawdzono na przykładzie projektowania obciążeń hydroelektrowni.
EN
Floating treatment wetlands (FTWs) with Water Dropwort (Oenanthe javanica) were established in winter to investigate their potential role in the purification of eutrophicated water, and to identify the effects of different stubble heights of the Water Dropwort on the performance of the FTWs. The results of the experiments demonstrated: The Water Dropwort FTWs were effective in buffering the pH of the experimental water. The Water Dropwort FTWs were efficient in purifying eutrophicated water, with removal rate for total nitrogen (TN), total phosphorus (TP), ammonium nitrogen ( NH N 4 + - ), and nitrate nitrogen ( NO N 3 - - ) at 91.3, 58.0, 94.6, and 95.5% in the 15-day experiment, respectively. No significant difference in the purification effect was found among different stubble heights of Water Dropwort FTWs. Significant differences between the zero control and the FTWs were found for the removal of TP in the first 11 days; and for the removal of NH N 4 + - in the first 4 days. No significant difference was found between the zero control and the FTWs for NO N 3 - - in the first 4 days, but significant difference was detected after day 4. The optimum treatment duration time for the FTWs with Water Dropwort will depend on the nutrients to be removed. These results will provide basis for further application of the FTWs at large scale, as well as for future studies on the mechanism of nutrient removal process.
PL
Badano proces oczyszczania wód z wykorzystaniem ruchomych mokradeł (FTW) obsadzonych Oenanthe javanica. Celem prowadzonych w zimie badań była ocena ich potencjalnej roli w oczyszczaniu wód zeutrofizowanych oraz określenie wpływu różnych wysokości ściernisk roślinnych na wydajność procesu. Wyniki eksperymentów wykazały, że systemy FTW skutecznie buforowały pH badanej wody. Za pomocą FTW ze zeutrofizowanej wody usunięto azot ogólny (TN), fosfor ogólny (TP), azot amonowy (NH N) 4 + - i azot azotanowy (NO N) 3 - - odpowiednio w ilościach: 91,3, 58,0, 94,6 i 95,5%, w czasie trwania 15-dniowego eksperymentu. Nie wykazano istotnych różnic w efekcie oczyszczania przy stosowaniu różnych wysokości ściernisk roślinnych. Stwierdzono wpływ czasu prowadzenia eksperymentu na usuwanie TP, którego usunięto najwięcej w pierwszych 11 dniach, a NH N 4 + - w ciągu pierwszych 4 dni trwania procesu. Nie stwierdzono istotnej różnicy między kontrolą i FTW dla NO N 3 - - w ciągu pierwszych kilku dni, ale znacząca różnica pojawiła się po 4 dniu. Optymalny czas trwania procesu z wykorzystaniem FTW zależy od składników odżywczych, które mają być usunięte. Opisane wyniki stanowią podstawę zarówno do rozwinięcia zastosowania FTW na dużą skalę, jak i dla przyszłych badań nad mechanizmem procesu usuwania składników odżywczych.
EN
The paper put forward the idea of sampling for gas hydrates by hole bottom freezing, and the method is that the temperature of the gas hydrate core is decreased on the hole bottom by cold source, the result of decreasing the temperature is the same as increasing pressure to inhibit gas hydrate dissociating and retains the core of gas hydrates. Firstly, the feasibility of hole bottom freezing method for sampling gas hydrates is analysed by research the temperature-pressure property. Secondly, it is confirmed that the dry ice is used as coolant, the alcohol as positive freezing catalyst and cooling medium by the indoor freezing experiment. Finally, the freezing sample tool is developed, the freezing loess sample is achieved. The research supplies the news ideas for the design of gas hydrates core sampler.
PL
Zaprezentowano ideę opróbowania hydratów gazowych przy zastosowaniu zamrażania dna otworu. Polega ona na tym, że temperatura rdzeniowanego materiału jest obniżana w dnie otworu, co wywołuje podobny efekt jak wzrost ciśnienia, uniemożliwając dysocjację pobieranych próbek hydratów. Zaproponowano użycie suchego lodu jako czynnika chłodzącego oraz alkoholu jako katalizatora procesu zamrażania. Przedstawiono nowe możliwości projektowania rdzeniówek do poboru próbek hydratów.
EN
. An equipment for in-situ testing the mean thermal conductivity of formation and borehole resistance is introduced in this paper, which provide a new approach to test the parameters of rock and soil for designing the ground source heat pump system(GSHPS). The parameters are tested under heat extraction situation of a single U-pipe heat exchanger and heat injection situation of a double U-pipe heat exchanger by using the device, and the conclusions are drawn that the mean thermal conductivity of formation of heat injection situation is larger than heat extraction situation, the calculating result of thermal conductivity of line source model is greater than cylinder source model, and the borehole thermal resistance of the double U-pipe is less than the single U-pipe heat exchanger.
PL
W artykule zaprezentowano aparaturę do badań in-situ średniej wartości przewodnictwa cieplnego i oporu cieplnego skał w otworach. Umożliwia ona nowe podejście do oceny parametrów skał i gruntów dla potrzeb projektowania systemów pomp ciepła (GSHPS). Stwierdzono między innymi, iż średnia wartość przewodnictwa cieplnego zmierzona w reżimie iniekcji ciepła jest wyższa od tejże, określonej w reżimie poboru ciepła. Wartości obliczone dla modelu źródła liniowego są wyższe niż dla modelu cylindrycznego.
11
Content available remote 3D fracture mechanics investigation on surface fatigue crack propagation
EN
Surface fatigue crack propagation is the typical failure mode of engineering structures. In this study the experiment on surface fatigue crack propagation in 15 MnVN steel plate is carried out and the crack-shape and propagation life are obtained. With the concept of "equivalent thickness" brought into the latest 3D (three dimensional) fracture mechanics theory, one closure model applicable to 3D fatigue crack is put forward. By using the above 3D crack-closure model, the shape and propagation life of surface fatigue crack in 15 MnVN plates are predicted. The simulative results show that the 3D fracture mechanics based closure model for 3D fatigue crack is effective.
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