Wyniki wyszukiwania - Biblioteka Nauki

1

Auto mission planning system design for imaging satellites and its applications in environmental field

100%

He Y. , Wang Y. , Chen Y. , Xing L.

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EN

Satellite hardware has reached a level of development that enables imaging satellites to realize applications in the area of meteorology and environmental monitoring. As the requirements in terms of feasibility and the actual profit achieved by satellite applications increase, we need to comprehensively consider the actual status, constraints, unpredictable information, and complicated requirements. The management of this complex information and the allocation of satellite resources to realize image acquisition have become essential for enhancing the efficiency of satellite instrumentation. In view of this, we designed a satellite auto mission planning system, which includes two sub-systems: the imaging satellite itself and the ground base, and these systems would then collaborate to process complicated missions: the satellite mainly focuses on mission planning and functions according to actual parameters, whereas the ground base provides auxiliary information, management, and control. Based on the requirements analysis, we have devised the application scenarios, main module, and key techniques. Comparison of the simulation results of the system, confirmed the feasibility and optimization efficiency of the system framework, which also stimulates new thinking for the method of monitoring environment and design of mission planning systems

2

Research on quantifying the hydrophilicity of leached coals by FTIR spectroscopy

88%

Wang J. , He Y. , Yang Y. , Xie W. , Ling X.

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tom Vol. 53, iss. 1

227--239

EN

Surface properties play important roles in characterization of structural parameters and the hydrophilicity index. Accurate analysis of the macerals rather than the average properties of the macerals and minerals are crucial for these parameters and indexes. In order to improve the accuracy of analyzing coal surface property, HF/HCl acid leaching was applied to eliminate the interference of minerals. FTIR was used to characterize the differences in surface chemical composition between raw and processed coal. Moreover, each functional group was analyzed quantitatively. Based on these quantitative data, the structural parameters and hydrophilicity indexes were calculated. From the results of FTIR, the peaks of mineral cover up the types of the organic peaks, such as -COOH and aromatic CH stretching. In addition, they decrease the intensity of the peak such as C=C and aromatics CHx out-of-plane deformation in the spectra of raw coals. However, it provided the accurate types and contents of organic functional groups of the macerals after acid leaching. The structural parameter results indicate that the values cannot reflect the coal ranks through the surface properties of raw coals while they show a good relationship with the degree of coalification in the analysis of processed coals. Besides, the hydrophilicity indexes are verified by the natural floatability of coal macerals of the processed coals. It is also found that the processed lignite coal cannot be floated despite elimination of the hydrophilic minerals. The main reason of hard-to-float property of lignite coal lies in a strong hydrophilicity of macerals.

3

Theoretical and Experimental Study on Detonation Wave Propagation in Cylindrical High Explosive Charges with a Wave-shaper

88%

Pan J. , Zhang X. , He Y. , Deng Q. , Guan Z.

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tom Vol. 13, no. 3

658--676

EN

The use of a cylindrical high-explosive charge with a wave-shaper is an efficient way to obtain an ultra-high pressure and a convergent detonation wave. An analysis of flow fields corresponding to the regular and Mach reflection of detonation waves in a cylindrical high-explosive charge with a wave-shaper is presented in this paper. The pressure, flow velocity and triple point growth angle of the Mach stem were calculated. The Mach stem height was also determined by using the modified Whitham method. The results show that the Mach stem height rises from zero at the critical angle of Mach reflection and changes to the Chapman-Jouguet detonation state with the propagation of the detonation waves. Shock indentation experiments were conducted, in which a wave-shaper was used in a cylindrical high-explosive charge to form Mach reflection detonation waves. The results showed that the discrepancy between the experimental results and the theoretical calculations was less than 15%, which proves the validity of the proposed theoretical model.

4

The effect of Ti addition on the microstructure and fracture toughness of BN-Al composite materials synthesized by vacuum infiltration

88%

Chao W. , Xiangxin X. , Xiaozhou C. , He Y. , Gongjin C.

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tom Vol. 58, iss. 2

509--512

EN

In this paper, we studied the effect of Ti addition on the microstructure and fracture toughness of Boron nitride- Aluminum (BN-Al) composite materials that were synthesized by vacuum infiltration. The BN-Al composite materials were fabricated by preheating the [Ti+BN] preforms at 1700º for 1 hour before Al alloys were infiltrated into the preforms in a vacuum atmosphere at 1100º for 2 hours. X-ray diffraction (XRD) patterns showed that the diffraction peaks of titanium diboride (TiB2) appeared when the [Ti+BN] preforms were preheated. It is thought that metal Al protected are visible and this could be achieved by the generation of TiB2 when Al infiltrated into the preform from fractography. The matching fracture toughness of the [Ti+BN] preforms gradually improve when Ti content was increased.

PL

W niniejszej pracy badano wpływ dodatku Ti na mikrostrukturę i odporność na pękanie kompozytów aluminium-azotek boru (BN-Al), które zostały zsyntetyzowane przez infiltracje w próżni. Kompozyty BN-Al zostały wykonane przez podgrzewanie preform [Ti+BN] w 1700ºC przez 1 godzinę, po czym stopy aluminium infiltrowano do preform w atmosferze próżni w temperaturze 1100ºC przez 2 godziny. Dyfrakcja rentgenowska (XRD) wykazała, że piki dyfrakcyjne diborku tytanu (TiB2) pojawiły się gdy preformy [Ti+BN] zostały podgrzane. Uważa się, że aluminium jest chronione co widoczne jest na przełomach i może to być osiągniete przez wytwarzanie TiB2 gdy Al przeniknęło do preformy. Odporność na pękanie preform [Ti+BN] stopniowo poprawia się, gdy zawartość Ti została zwiększona.

5

Energetic asymmetry connected with energy flow changes in response to eutrophication: a study of multiple fish species in subtropical shallow lakes

76%

Fu H. , Zhang H. , He L. , Sha Y. , Zhao K. , He Y. , Xu J.

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nr 4

6

Gradient elution LC-MS determination of dasatinib in rat plasma and its pharmacokinetic study

76%

Wen C. , Zhang Q. , He Y. , Deng M. , Wang X. , Ma J.

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tom Vol. 27, no. 1

81--91

EN

A sensitive and simple liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method for determination of dasatinib in rat plasma using one-step protein precipitation was developed. After addition of carbamazepine as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on an SB-C18 (2.1 mm × 150 mm, 5 μm) column with methanol-0.1% formic acid as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selective ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 488.2 for dasatinib and m/z 338.7 for the IS. Calibration plots were linear over the range of 10–1000 ng mL−1 for dasatinib in rat plasma. Lower limit of quantification (LLOQ) for dasatinib was 10 ng mL−1. Mean recovery of dasatinib from plasma was in the range 82.2%–93.6%. Relative standard deviation (RSD) of intra-day and inter-day precision were both less than 8%. This developed method is successfully used in pharmacokinetic study of dasatinib in rats.

7

The influence of new herbicide ZJ0273 on the total - and branched - chain amino acids in oilseed rape (Brassica napus L.) leaves as revealed by near-infrared spectroscopy

63%

Tian T. , Jin Z. , Ali B. , Guo X. , Liu F. , Zhang F. , Zhang W. , He Y. , Zhou W.

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nr 08

EN

Propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy) benzylamino)benzoate (ZJ0273) is a new herbicide which inhibits acetolactate synthase (ALS). The ZJ0273 is considered as safe for the environment and exhibits a satisfactory effect on weed control in the rapeseed field. ALS is the key enzyme of reactions in the biosynthesis of total amino acids (TAAs) especially branched-chain amino acids (BCAAs). This study reports the effect of ZJ0273 on BCAAs and TAAs in rapeseed leaves using near-infrared spectroscopy (NIRS) techniques. A decrease in TAAs and BCAAs contents was observed as the herbicide dosages were increased along with leaf senescence. The wavelengths 2,416 and 1,340 nm were selected to develop the NIRS model for detecting BCAAs and TAAs, and correlation coefficients of model’s prediction set were 0.9823, 0.9764, 0.9831, and 0.9968 for valine, isoleucine, leucine, and TAAs, respectively. The results indicated that 100 mg/L ZJ0273 was a safe dosage for oilseed rape as it did not show a significant effect on the contents of amino acids compared to other higher dosages (500 and 1,000 mg/L).

8

Variations of sediment archaea communities in different distribution areas of Bruguiera gymnoihiza Mangrove in Dongzhaigang, China

63%

Li W. , Guan W. , Chen H. , Liao B. , Hu J. , Rui J. , Peng C. , Zhu D. , He Y. , Tian J.

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nr 5

EN

Archaea communities widely exist in mangrove forest sediments, but their spatial variations among different distribution areas with salinity gradient in mangrove forest sediments is not well understood. This study used 16S rRNA Miseq sequence to investigate the sediment archaeal community structure and diversity of Bruguiera gymnoihiza mangrove forest in China along three different distribution areas. The results showed rich methanogen and ammonia-oxidizing archaea resources in the study site, with Methanobacterium, Methanothrix, Methanomassiliicoccus, Nitrosopumilus and Nitrososphaera (>1%) as the dominant genera. Mantel test and Redundancy analysis (RDA) results revealed that pH was the determinant for archaeal community structure in our study. The RDA result showed that the available K also contributed to archaeal community structure. There was a significant and positive relationship between pH and available P; in addition, the two values were significantly and negatively related to the observed OTU number. These results suggested that pH is the main determinant of the archaeal community structure and diversity in distribution areas of Bruguiera gymnoihiza in Dongzhaigang.