In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and sca...
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In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C-18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection.
In this work, reduced graphene oxide coated with ZnO (RGO-ZnO) nanocomposites was synthesized by a hydrothermal reduction strategy. The presence of ZnO was characterized by Fourier transform infrared spectroscopy (FT-...
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In this work, reduced graphene oxide coated with ZnO (RGO-ZnO) nanocomposites was synthesized by a hydrothermal reduction strategy. The presence of ZnO was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Subsequently, RGO-ZnO was used as a dispersive solid-phase extraction (DSPE) sorbent for the enrichment of eight organophosphorus pesticides (OPs) in apple, cucumber and water samples prior to their determination by gas chromatography-mass spectrometry (GC-MS). Several experimental parameters affecting the extraction efficiencies, including the amount of RGO-ZnO, extraction time, and the pH of the sample solution, as well as the type and volume of eluent solvent, were investigated and optimized in this work. Under the optimal experimental conditions, good linearity existed in the range of 0.5-200.0 ng g(-1) for all the analytes with the correlation coefficients (R-2) ranging from 0.9894 to 0.9983. The limits of detection (S/N = 3) of the method for the compounds were between 0.01 and 0.05 ng g(-1). Good reproducibilities were acquired with the relative standard deviations (RSDs) below 8.6% for both intra-day and inter-day precision. The recoveries of the method were in the range of 75.0% to 104.2%.
Fluorinated liquid crystal polymers (FLCPs) with an AB/A(2)B-alternating sequence of fluorinated biphenyl moieties (FMs) along their backbones were constructed, where the anionic copolymerization of isoprene (Ip) with...
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Fluorinated liquid crystal polymers (FLCPs) with an AB/A(2)B-alternating sequence of fluorinated biphenyl moieties (FMs) along their backbones were constructed, where the anionic copolymerization of isoprene (Ip) with, mono-SiH and di-SiH functionalized 1,1-diphenylethylene (DPE) derivatives was performed to prepare alternating copolymer precursors with exactly controlled single-site densities of -SiH, i.e., alt-P(D-S/Ip) and alt-P(D-2S/Ip), respectively, followed by highly efficient hydrosilylation to introduce FMs into the repeating unit (DPE). Previous work indicated that the mesogenic properties were related to the distance between neighbouring mesogenic moieties in different polymerized units when the degree of polymerization (DP) of the copolymers was low. Hence, the present strategy provides a novel model to explore dependence of the mesogenic properties on the exactly controlled single-site functionalized density of mesogens (FMs) for the resulting alternating-templated FLCPs, which was achieved due to a quite low DP (11 for mono-SiH and 5 for di-SiH), while exhibiting a similar overall concentration of FMs along backbones bearing a similar number of Si-H groups. The results show that the polarized optical textures and the temperature range of mesogenic phase formation (Delta T) varied remarkably between A(2)B-alternating (Delta T = 104 degrees C) and AB-alternating (Delta T = 23 degrees C) FLCPs;in particular, the variation in phase transition temperature is possibly a result of exactly controlled single-site functionalized density. Herein, a novel morphological aggregation model is proposed to increase the comprehension of how the exactly controlled single-site functionalized density of FMs arranged within the small scale of polymer chains directs molecular packing and interactions between them, thereby enriching the diversity of molecular interactions.
This paper studies on hardware design of a novel patient monitor based on one ADSP-BF548 blackfin dsp. The NIBP, 12-lead ECG, SPO2 and body temperature functions are successfully implemented. A 6.4 inch TFT LCD with a...
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The Influenceof Rare Earth Element on alpha-Solidification of A356 Alloy has been discussed in the paper. It is showed by the research, that the condition of interphase is changed by Rare Earth element asymmetry distr...
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ISBN:
(纸本)9780878492039
The Influenceof Rare Earth Element on alpha-Solidification of A356 Alloy has been discussed in the paper. It is showed by the research, that the condition of interphase is changed by Rare Earth element asymmetry distribution, which influences the process of a phase growing and facilitates the growth of alpha phase in sphere, and leads to a optimal Rare Earth quantity for facilitative effect, which is 0.5% in this experimentation, and that alpha phase grain will be change to small by adding Rare Earth.
The measurement of volume pulse waves may be easily affected based on the measured position (different fingers or toes), body posture, as well as other factors. Therefore, interferences during measurement need to be r...
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The measurement of volume pulse waves may be easily affected based on the measured position (different fingers or toes), body posture, as well as other factors. Therefore, interferences during measurement need to be removed. For this study, relevant parameters of volume pulse wave were obtained by changing the affecting factors. The data were analyzed in order to indicate the differences in volume pulse wave parameters among different fingers and toes in four postures. Results showed that when subjects were lying, inclined or in a sitting posture, volume pulse wave parameters of the index finger, middle finger and ring finger on both hands displayed no apparent differences. When subjects were in a sitting posture, volume pulse wave parameters of the big, second and third toes on both feet showed no significant differences.
A simple and sensitive method for determination of three aconitum alkaloids and their metabolites in human plasma was developed using matrix solid-phase dispersion combined with vortex-assisted dispersive liquid-liqui...
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A simple and sensitive method for determination of three aconitum alkaloids and their metabolites in human plasma was developed using matrix solid-phase dispersion combined with vortex-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection. The plasma sample was directly purified by matrix solid-phase dispersion and the eluate obtained was concentrated and further clarified by vortex-assisted dispersive liquid-liquid microextraction. Some important parameters affecting the extraction efficiency, such as type and amount of dispersing sorbent, type and volume of elution solvent, type and volume of extraction solvent, salt concentration as well as sample solution pH, were investigated in detail. Under optimal conditions, the proposed method has good repeatability and reproducibility with intraday and interday relative standard deviations lower than 5.44 and 5.75%, respectively. The recoveries of the aconitum alkaloids ranged from 73.81 to 101.82%, and the detection limits were achieved within the range of 1.6-2.1 ng/mL. The proposed method offered the advantages of good applicability, sensitivity, simplicity, and feasibility, which makes it suitable for the determination of trace amounts of aconitum alkaloids in human plasma samples.
Since the semiconductor technology has entered the age of 90 nm, the static power consumption of the chip has increased rapidly. For edge computing devices, the waste of power can not be ignored. This paper uses the r...
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Electronic image stabilization (EIS) technology is an important research area of video processing and computer vision. This paper presented a set of fast and parallel EIS algorithms. Firstly, this paper proposed a fas...
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ISBN:
(纸本)9780769551203
Electronic image stabilization (EIS) technology is an important research area of video processing and computer vision. This paper presented a set of fast and parallel EIS algorithms. Firstly, this paper proposed a fast local motion vector (LMV) estimation algorithm based on the FAST feature to solve the problem that the traditional algorithm is too complex. Secondly, a parallel global motion vector (GMV) algorithm based on image division is designed, which computes every LMV simultaneously, and then estimates the GMV by all LMVs. Finally, based on the proposed algorithm, an EIS systems based on BF609 dual-core DSP processor is designed and implemented. Experiment results show that the algorithm and system presented in this thesis can effectively stabilize jittery video and achieve high real-time performance. When dealing with PAL standard video, the total time cost is less than 40ms.
Contraposing the basic principles and mechanism of the real-time operating system, the paper has compared general operating systems with real-time operating system, and made a good effort to analyze the key factors wh...
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ISBN:
(纸本)9781424436927
Contraposing the basic principles and mechanism of the real-time operating system, the paper has compared general operating systems with real-time operating system, and made a good effort to analyze the key factors which may affect the real-time characteristics of operating system, and then given a assessment methods to evaluate the real-time character of operating system. A practical application system is also tested at last.
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