94 research outputs found

    Study on Flavor Characteristics and Nutritional Evaluation of Free Amino Acids in Walnut Pellicle

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    In order to explore the composition, taste characteristics and nutritional value of free amino acids in pellicle of different varieties of walnut, the content of free amino acid in the pellicle of 6 walnut varieties was detected, and the taste activity value (TAV) analysis, principal component analysis and comprehensive evaluation were carried out. The results showed that a total of 17 free amino acids could be detected in the pellicle of walnut, with a total content of 2673.86~3490.12 mg/kg. Nine medicinal amino acids accounted for 57.67%~68.23% of the total amino acids, and Leu was the first limiting amino acid in the pellicle. Glu, Asp, Thr, Cys and Arg were the main amino acids of free amino acids in the pellicle, with Glu having the highest content. The TAV value of Glu among the six cultivars was 2.34~3.81, which contributed the most to the umami of the pellicle. The TAV values of Arg in 'Jing 861', 'Bokexiang' and 'Jinboxiang 8' were 1.03~1.26, which contributed to the bitterness of the pellicle. Among the flavor amino acids, the content of umami amino acids was the highest, while aromatic amino acids had the lowest contentm. The ratio of bitter to sweet amino acid content in the 'Nonghe 1', 'Jing 861', 'Bokexiang' and 'Jinboxiang 8' was greater than 1. While the ratio of bitter to sweet amino acid content in the 'Fenhe 2' and ' Fenhe 4' was less than 1. The comprehensive quality of amino acids was also relatively higher. The amino acids in pellicle had high nutritional value and medicinal value, and the taste was bitter, as a food auxiliary material to supplement Thr, Ile and sulfur-containing amino acids, it could increase the overall taste richness of food

    The Impacts of Emission Control and Regional Transport on PM2.5 Ions and Carbon Components in Nanjing during the 2014 Nanjing Youth Olympic Games

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    Highly time-resolved measurements of water soluble ions, organic and elemental carbon concentrations in the particle diameter size range D-p <2.5 mu m (PM2.5) were performed at a downwind urban site in Nanjing in the western part of the Yangtze River Delta (YRD) in eastern China during the 2014 Youth Olympic Games (YOG). In this study, we discuss the impacts of emission control in Nanjing and the surrounding areas during the YOG and regional/long-range transport on PM2.5 pollution in Nanjing. The average concentrations of NO3-, SO42-, NH4+ were 12.1 +/- 9.9, 16.5 +/- 9.2, 9.0 +/- 5.4 mu g m(-3) during the YOG, and increased 34.3%, 53.7%, 43.9% after the YOG, respectively. The control of construction or on-road soil dust and control of industry led to the decrease of Ca2+ concentration by 55% and SO2 concentration by 46%. However, SO42- concentrations remained at relatively high levels, suggesting a significant impact of regional pollution to secondary fine particles in Nanjing. Strong correlations between OC and EC were observed during and after the YOG. A higher percentage (41%) of secondary organic carbon in Nanjing during the YOG periods was consistent with high potential photochemistry and low contributions from coal combustion. Lagrangian dispersion modelling results proved that the city clusters along the Nanjing and Shanghai axis were the major source region for high PM2.5 pollution in upwind Nanjing. This work shows that short-term strict control measures could improve the air quality, especially that affected by the primary pollutants; however, regional collaborative control strategy across administrative borders in the YRD is needed for a substantial improvement of air quality.Peer reviewe

    Spatially explicit analysis identifies significant potential for bioenergy with carbon capture and storage in China

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    As China ramped-up coal power capacities rapidly while CO2 emissions need to decline, these capacities would turn into stranded assets. To deal with this risk, a promising option is to retrofit these capacities to co-fire with biomass and eventually upgrade to CCS operation (BECCS), but the feasibility is debated with respect to negative impacts on broader sustainability issues. Here we present a data-rich spatially explicit approach to estimate the marginal cost curve for decarbonizing the power sector in China with BECCS. We identify a potential of 222 GW of power capacities in 2836 counties generated by co-firing 0.9 Gt of biomass from the same county, with half being agricultural residues. Our spatially explicit method helps to reduce uncertainty in the economic costs and emissions of BECCS, identify the best opportunities for bioenergy and show the limitations by logistical challenges to achieve carbon neutrality in the power sector with large-scale BECCS in China

    Effect of live poultry market interventions on influenza A(H7N9) virus, Guangdong, China

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    Since March 2013, three waves of human infection with avian influenza A(H7N9) virus have been detected in China. To investigate virus transmission within and across epidemic waves, we used surveillance data and whole-genome analysis of viruses sampled in Guangdong during 2013–2015. We observed a geographic shift of human A(H7N9) infections from the second to the third waves. Live poultry market interventions were undertaken in epicenter cities; however, spatial phylogenetic analysis indicated that the third-wave outbreaks in central Guangdong most likely resulted from local virus persistence rather than introduction from elsewhere. Although the number of clinical cases in humans declined by 35% from the second to the third waves, the genetic diversity of third-wave viruses in Guangdong increased. Our results highlight the epidemic risk to a region reporting comparatively few A(H7N9) cases. Moreover, our results suggest that live-poultry market interventions cannot completely halt A(H7N9) virus persistence and dissemination

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    A reference current source with a low temperature coefficient

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    In view of the high demand for low temperature coefficient reference current sources in integrated circuits, the advantages and disadvantages of several typical reference current sources in circuit structure and temperature characteristics are compared. In this paper, a low temperature coefficient reference current source is designed. Based on Hua Hong HHNECGE 0.35um process, the output current is 0.4uA, the temperature range is -40°C-125°C, and the temperature coefficient is 7.6ppm/°C under typical process angle. Other processes The temperature coefficient under the corner is at 10ppm/°C

    RESEARCH ON POST-PROCESSING METHOD OF CONTINUUM STRUCTURE TOPOLOGY OPTIMIZATION BASED ON VARIABLE DENSITY METHOD

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    The variable density method has become an effective method to solve the topology optimization problem of continuum structure due to its advantages such as few design variables and high efficiency. Aiming at the problem of the gray unit and sawtooth boundary in the optimization process of the variable density method, a post-processing method of variable density method for continuum topology optimization is proposed in this paper. The topology optimization model is binarized and the sawtooth shape boundary line is extracted, and the target discrete corner point set is obtained, used as the sample point for curve fitting to obtain the optimized structure with smooth boundary. Experimental results show that this method effectively avoids the zigzag boundary and intermediate density of the optimization result, and improves the manufacturability of the optimization result under the premise of ensuring that the structural performance is within the allowable range

    Screening and Enzymatic-producing Study of Chitin Deacetylase Producing Bacteria-Lysinibacillus sp.

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    In order to biodegrade natural chitin, in this study, chitin was used as the sole carbon source, obtain chitin deacetylase strains which could produce chitosan from natural chitin by biological method. Results showed that, the strains were identified by color plate screening and enzyme activity rescreening, morphological characteristics and 16S rRNA sequence analysis. A bacterium X4 with higher activity of chitin deacetylase was obtained, and was identified as Lysinibacillus sp.. The fermentation culture of the strain showed that the activity of chitin deacetylase produced by X4 could reached 8.210 U/mL, and the deacetylation degree of chitin was 8.642%. The results was valuable for the green biological utilization of chitin

    A Continuous-Time-Based MILP Model for Production and Transportation Scheduling in Nonpipelined Wells in Low-Permeability Oil Fields

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    AbstractThe marginal wells in low-permeability oilfields are characterized by small storage size, scattered distribution, large regional span, low production, intermittent production, etc. The production mode of these wells is nonpipeline mode. In our previous work (Zhang et al., 2019), a novel mixed-integer linear programming (MILP) model using a discrete-time representation was presented for the operation scheduling of nonpipelined wells. However, too many discretization time points are required to ensure the accuracy of the model. Even for moderately sized problems, computationally intractable models can arise. The present paper describes a new continuous-time representation method to reformulate this schedule optimization problem. By introducing the continuous-time representation, the binary variables are largely reduced. The solution effect for different model sizes is also investigated. When the model size increases to a certain degree, a feasible solution cannot be obtained within a limited time. The results of a case study originated from a real oilfield in China show that the continuous-time model requires less time to obtain the optimal solution compared to the discrete-time model. In details, considering a same scale problem, the solution based on the continuous-time model saves 52.25% of the time comparing with the discrete-time model. The comparison validates the new model’s superiority
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