69 research outputs found

    Responses of Soil Organic Carbon Sequestration Potential and Bacterial Community Structure in Moso Bamboo Plantations to Different Management Strategies in Subtropical China

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    Moso bamboo is one of the fastest-growing plants in the world. The objective of this study was to investigate the impact of converting secondary broadleaf evergreen forests (CK) to Moso bamboo plantations, and the impact of different management strategies, including no disturbance (M0), extensive management (M1), and intensive management (M2), on the soil organic carbon (SOC) sequestration potential, and relevant characteristics of the soil bacterial community. Our results showed that, in comparison with CK, M0 and M1 had significantly higher SOC and recalcitrant organic materials (aliphatic and aromatic compounds), and a lower C mineralization rate, whereas M2 had the opposite effects. The conversion from CK to Moso bamboo plantation significantly decreased the relative abundance of Acidobacteria in both the topsoil and subsoil soil layers. Compared with CK, M0 led to the enrichment of bacteria such as Alphaproteobacteria, Chloroflexi, and Bacteroidetes, which are involved in the decomposition of organic matter and the formation of humus and are, therefore, potentially beneficial for increasing the SOC. Furthermore, the ratio of the microbial biomass C (MBC) to total organic C (TOC), C mineralization rate, and bacterial diversity increased from M0 to M2, i.e., with an increase in the disturbance intensity. These findings indicate that the conversion of secondary broadleaf forest to bamboo forest alter the soil bacterial community structure. Reducing disturbance in bamboo forest management strategies should be actively taken up to improve the SOC, and maintain sustainable development in the forest industry

    Fabrication of Hollow and Yolk-Shell Structured eta-Fe2O3 Nanoparticles with Versatile Configurations

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    A solution-based approach has been developed for the synthesis of hollow or yolk-shell structured eta-Fe2O3 nanoparticles with versatile configurations via the Ostwald ripening process. By simply controlling the amount of PVP and reaction time in solution, hollow or yolk-shell structured eta-Fe2O3 nanoparticles with spherical, egg-like, olivary, elliptical, and shuttle-like configurations can be easily fabricated. The interior structures and morphologies of the particles are found to be effective ways to affect both the specific saturation magnetization and coercivity of the eta-Fe2O3 nanoparticles

    Responses of Soil Organic Carbon Sequestration Potential and Bacterial Community Structure in Moso Bamboo Plantations to Different Management Strategies in Subtropical China

    No full text
    Moso bamboo is one of the fastest-growing plants in the world. The objective of this study was to investigate the impact of converting secondary broadleaf evergreen forests (CK) to Moso bamboo plantations, and the impact of different management strategies, including no disturbance (M0), extensive management (M1), and intensive management (M2), on the soil organic carbon (SOC) sequestration potential, and relevant characteristics of the soil bacterial community. Our results showed that, in comparison with CK, M0 and M1 had significantly higher SOC and recalcitrant organic materials (aliphatic and aromatic compounds), and a lower C mineralization rate, whereas M2 had the opposite effects. The conversion from CK to Moso bamboo plantation significantly decreased the relative abundance of Acidobacteria in both the topsoil and subsoil soil layers. Compared with CK, M0 led to the enrichment of bacteria such as Alphaproteobacteria, Chloroflexi, and Bacteroidetes, which are involved in the decomposition of organic matter and the formation of humus and are, therefore, potentially beneficial for increasing the SOC. Furthermore, the ratio of the microbial biomass C (MBC) to total organic C (TOC), C mineralization rate, and bacterial diversity increased from M0 to M2, i.e., with an increase in the disturbance intensity. These findings indicate that the conversion of secondary broadleaf forest to bamboo forest alter the soil bacterial community structure. Reducing disturbance in bamboo forest management strategies should be actively taken up to improve the SOC, and maintain sustainable development in the forest industry

    Role of anions on structure and pseudocapacitive performance of metal double hydroxides decorated with nitrogen-doped graphene

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    Electrochemical capacitors (EC) bear faster charge-discharge; however, their real applications are still on a long away due to lower capacitance and energy densities which mainly arise from simple surface charge accumulation or/and reaction. Here, a novel synthesis strategy was designed to obtain the purposeful hybrids of nickel cobalt double hydroxide (NiCoDH) with genetic morphology to improve their electrochemical performance as electrode of EC. Nanostructures of metal hydroxides were grown on t he nitrogen-doped graphene (NG) sheets by utilizing defects as nucleation sites and their composition was optimized both by tuning the ratio of Ni:Co as well as the counter halogen and carbonate anions to improve the porosity, stabilize the structure and mediate the redox reaction. The growth of the hybrids was guided by the Co ions through topochemical transformation supported by hoping charge transfer process and olation growth. NG overcoating successfully protects the nanostructure of NiCoDH during electrochemical test and enhances overall conductivity of the electrode, improving the mass and ionic transportations. As a result, the hybrid exhibits excellent capacitance of 2925 F g−1 at 1 A g−1, as well as long cyclic stability of 10,000 cycles with good capacity retention of 90% at 16 A g−1. Furthermore, the hybrid shows excellent energy and power densities of 52 Wh kg−1 and 3191 W kg−1, respectively at discharge rate of 16 A g−1. It is expected that this strategy can be readily extended to other metal hydroxides, oxides and sulphides to improve their electrochemical performances

    Effect of preinitiated glucose-insulin-potassium strategy for patients with undergoing planned percutaneous coronary intervention: a systematic review and meta-analysis

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    Objectives Whether the glucose-insulin-potassium (GIK) should be used as an adjuvant therapy for ischaemic myocardial disease remains controversial nowadays reperfusion era. This meta-analysis aimed to assess the effects of preinitiated GIK for patients undergoing planned percutaneous coronary intervention (PCI).Design Systematic review and meta-analysis.Data sources PubMed, Web of science, MEDLINE, Embase, Cochrane Library and ClinicalTrials.gov were searched through 27 November 2022.Eligibility criteria Only randomised controlled trials involving participants preinitiated with GIK or placebo before planned PCI were included.Data extraction and synthesis Two independent reviewers used standardised methods to search, screen and code included trials. Risk of bias was assessed with the Cochrane tool. Pooled analysis was conducted using random or effects models according to the heterogeneity. Subgroup analyses were carried out for dosage of GIK and if with ongoing myocardial ischaemia.Results 13 randomised controlled trials (RCTs) including 3754 participants were evaluated. We found patients preconditioned with GIK before PCI showed a significant increase in Thrombolysis in Myocardial Infarction 3 flow events after angioplasty (OR 1.59, 95% CI 1.03 to 2.46, p=0.04), also revealed improved in-hospital left ventricular ejection fraction (weighed mean difference, WMD 1.62, 95% CI 0.21 to 3.03, p=0.02) and myocardial salvage index (WMD 0.09, 95% CI 0.01 to 0.16, p=0.03). Nevertheless, no benefit was observed in all-cause mortality neither on 30-day (OR 0.81, 95% CI 0.59 to 1.11, p=0.18) nor 6 months (OR 1.02, 95% CI 0.42 to 2.46, p=0.97). Furthermore, GIK intervention was associated with higher occurrences of complications such as phlebitis (OR 10.13, 95% CI 1.74 to 59.00, p=0.01) and hypoglycaemia (OR 10.43, 95% CI 1.32 to 82.29, p=0.03), but not hyperkalaemia (OR 9.36, 95% CI 0.50 to 175.27, p=0.13), liquid overload (OR 1.02, 95% CI 0.25 to 4.13, p=0.98) or in-hospital heart failure (OR 0.42, 95% CI 0.06 to 2.96, p=0.39).Conclusions Our study shows preconditioning GIK exhibits myocardial reperfusion and cardiac function benefits for patients planning to receive PCI intervention, while also some complications such as phlebitis and hypoglycaemia accompany.PROSPERO registration number CRD42022326334

    A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

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    The prediction of permeability and the evaluation of tight oil reservoirs are very important to extract tight oil resources. Tight oil reservoirs contain enormous micro/nanopores, in which the fluid flow exhibits micro/nanoscale flow and has a slip length. Furthermore, the porous size distribution (PSD), stress sensitivity, irreducible water, and pore wall effect must also be taken into consideration when conducting the prediction and evaluation of tight oil permeability. Currently, few studies on the permeability model of tight oil reservoirs have simultaneously taken the above factors into consideration, resulting in low reliability of the published models. To fill this gap, a fractal permeability model of tight oil reservoirs based on fractal geometry theory, the Hagen–Poiseuille equation (H–P equation), and Darcy’s formula is proposed. Many factors, including the slip length, PSD, stress sensitivity, irreducible water, and pore wall effect, were coupled into the proposed model, which was verified through comparison with published experiments and models, and a sensitivity analysis is presented. From the work, it can be concluded that a decrease in the porous fractal dimension indicates an increase in the number of small pores, thus decreasing the permeability. Similarly, a large tortuous fractal dimension represents a complex flow channel, which results in a decrease in permeability. A decrease in irreducible water or an increase in slip length results in an increase in flow space, which increases permeability. The permeability decreases with an increase in effective stress; moreover, when the mechanical properties of rock (elastic modulus and Poisson’s ratio) increase, the decreasing rate of permeability with effective stress is reduced

    A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

    No full text
    The prediction of permeability and the evaluation of tight oil reservoirs are very important to extract tight oil resources. Tight oil reservoirs contain enormous micro/nanopores, in which the fluid flow exhibits micro/nanoscale flow and has a slip length. Furthermore, the porous size distribution (PSD), stress sensitivity, irreducible water, and pore wall effect must also be taken into consideration when conducting the prediction and evaluation of tight oil permeability. Currently, few studies on the permeability model of tight oil reservoirs have simultaneously taken the above factors into consideration, resulting in low reliability of the published models. To fill this gap, a fractal permeability model of tight oil reservoirs based on fractal geometry theory, the Hagen–Poiseuille equation (H–P equation), and Darcy’s formula is proposed. Many factors, including the slip length, PSD, stress sensitivity, irreducible water, and pore wall effect, were coupled into the proposed model, which was verified through comparison with published experiments and models, and a sensitivity analysis is presented. From the work, it can be concluded that a decrease in the porous fractal dimension indicates an increase in the number of small pores, thus decreasing the permeability. Similarly, a large tortuous fractal dimension represents a complex flow channel, which results in a decrease in permeability. A decrease in irreducible water or an increase in slip length results in an increase in flow space, which increases permeability. The permeability decreases with an increase in effective stress; moreover, when the mechanical properties of rock (elastic modulus and Poisson’s ratio) increase, the decreasing rate of permeability with effective stress is reduced

    Risk Analysis of HPEM Threats for Linear RF Channel with Pyramid Horn Antenna Based on System-Level SPICE Modeling

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    High power electromagnetics (HPEMs) pose a potential threatening risk to the wireless communication system, especially according to the main coupling path of the RF front-end channel. SPICE modeling of the responses coupled on the RF channel is crucial for the EM risk assessment, which helps us learn more about how the pulse conducts on the RF channel. A simplified linear RF channel with pyramid horn antenna is taken as an example by the selection of the key electronic modules of the actual wireless system. This paper proposes a system-level SPICE circuit model for the simplified RF channel according to the hybrid methods of the antenna electromagnetic simulation and SPICE modeling of the RF circuit. The equivalent circuits of the horn antenna illuminated by HPEMs are established with the Vector Fitting method based on Thevenin and Norton theorems. The short current response as the excitation files for the SPICE models are obtained by the commercial electromagnetic simulation of the horn antenna illuminated by Multiple HPEM environments. Equivalent circuits of a micro-strip bandpass filter are also derived with π type circuit structure based on the measured admittance data. Then we analyze the HPEM risk faced by the RF channel by considering multiple HPEM environments. The norm theory is utilized to analyze the waveform characteristics from electric fields of HPEMs to the responses of the RF channel. The ratios of the responses versus electric field for each norm are computed and the EM risk degree is ranked based on those results. The results demonstrate that high power microwave is the highest threatening risk for the linear RF channel compared to the other two HPEMs such as ultra-wide band, high altitude electromagnetic pulse. Finally, the flowchart of EM risk assessment is presented based on a previous analysis, which will benefit the EMC design in engineering
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