57 research outputs found

    Harmonic Quantitative Analysis for Dead-time Effects in SPWM Inverters

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    Multisampling Method for Single-Phase Grid-Connected Cascaded H-Bridge Inverters

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    The Closed-Loop Sideband Harmonic Suppression for CHB Inverter With Unbalanced Operation

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    Relationship between Carotid Artery Sclerosis and Blood Pressure Variability in Essential Hypertension Patients

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    Objectives: This study aimed to investigate the relationship between the presence of carotid arteriosclerosis (CAS) and blood pressure variability (BPV) in patients with essential hypertension. Methods: One hundred and forty four essential hypertension patients underwent ambulatory BP monitoring for 24 hours after hospitalization. Common BPV metrics were calculated. General clinical parameters, including age, gender, height, weight, history of coronary heart disease, stroke, diabetes, hypertension, smoking and drink, were recorded. Biochemical indices were obtained from a blood test. Carotid intima-media thickness (IMT) and carotid plaques were assessed to separate patients into a non-CAS group (IMT≤0.9 mm; n=82) and a CAS group (IMT>0.9 mm; n=62). BPV metrics and clinical parameters were analyzed and compared between the two groups. Multivariate logistic regression analysis was performed to determine the associated risk factors of CAS. Results: Multivariate logistic regression analysis revealed that two BPV metrics, the standard deviation of daytime systolic blood pressure (SSD) (OR: 1.587, 95%CI: 1.242–2.028), the difference between average daytime SBP and nighttime SBP (OR: 0.914, 95%CI: 0.855-0.977), as well as three clinical parameters (age, OR: 1.098, 95%CI: 1.034-1.167; smoking, OR: 4.072, 95%CI: 1.466–11.310, and fasting blood glucose, OR: 2.029, 95%CI: 1.407–2.928), were significant factors of CAS in essential hypertension patients. Conclusion: SSD, in combination with the ageing, smoking and FBG, has been identified as risk factors for CAS in patients with essential hypertension

    Effect of Geobacter metallireducens nanowire on electron transfer efficiency in microbial fuel cell

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    BACKGROUND To understand the effect of electron shuttle compounds on the electron transfer behavior of MFC and the formation process of microbially fabricated nanowires. In this paper, 2,6-anthraquinone desulfonation (AQDS) and Fe(OH)(3) were used as electron mediator and electron acceptor, respectively, to study the effect of electron mediator on the formation of bio-nanowires during the growth of Geobacter metallireducens in the double chamber MFC reactor (MFC), and the effects of electron transfer efficiency and electrical current characteristic. RESULTS The results show that the culture process of the Geobacter metallireducens with Fe(OH)(3) as an electron acceptor, the reduction product Fe(II) concentration in solution without AQDS was higher than that with AQDS after 10 days due to the formation of microbial nanowires. In comparison, the Pili protein content of the system without AQDS reached 336 ug/mL, which was higher than the AQDS system. Nanowires increased the transfer efficiency between biofilm and electrodes, which increased the maximum output voltage of MFC was 442 mV. CONCLUSION At the same time, it was found by electrochemical measurements that the nanowire biofilm electrode had a huge peak of the cyclic voltammetry curve, a small activation resistance, and a strong current response signal, indicating that the nanowires enhanced the electrochemical activity of the electrode. In addition, an electron transfer medium (AQDS) inhibited the expression of aromatic amino acids, tryptophan, and mtrC. Moreover, it destroyed the overlapping pi-pi orbits of the aromatic parts, resulting in reduced and thinner nanowires and then decreasing the conductivity of synthetic organic materials like metals. (c) 2022 Society of Chemical Industry (SCI)

    Separation of vanadium and tungsten in roasting-acid leaching solutions of the spent selective catalytic reducing denitration catalyst by co-extraction using hydroxyoxime extractant-quaternary ammonium salt extractant LIX984-N263 extractant

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    This study presents a synergistic extraction and recovery of vanadium and tungsten by mixed extractants (LIX984 and N263) from an acid leaching solution which was obtained from spent denitrification catalysts by chlorination heat treatment and acid leaching. Through thrice counter-flow extraction, 99.5% V and 99.7% W were extracted, while 3.0% Fe, 2.9% Ti, 2.1% P, and 3.3% Mg were co-extracted at a LIX984:N263 volume content of 22.0%, the phase ratio of 2.5 and the mother liquor's pH of 2.5. Then, at 0.80 mol/l NaOH and a phase ratio of 1, 99.9% tungsten and 99.1% vanadium were stripped from the organic phase to the aqueous phase. Subsequently, the aqueous phase's tungsten of 99.3% and vanadium of 98.1% were separated as calcium tungstate and ammonium metavanadate, respectively. In contrast, the residual solutions containing tungsten and vanadium can be returned to the following purification separation process to recover the valuable metals from the solution. Roasting converts the precipitated calcium tungstate and ammonium metavanadate to V2O5 and WO3 products. In addition, the thermodynamic analysis found the separation and recovery of tungsten and vanadium from the acid leach solution with LIX984:N263 to be an exothermic process. This method can be effectively extended for the separation of vanadium and tungsten from spent denitrification catalysts by the proposed process and validates the conclusion that metals with similar properties can be extracted using a mixture of extractants

    Recovery and kinetics of gold and vanadium from vanadium-bearing carbonaceous gold by chlorination roasting-acid leaching

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    The idle mining or flotation decarburization of vanadium-bearing carbonaceous gold ores polluted the environment and wasted resources. In this paper, the volatilization behavior of calcined gold and the extraction kinetics of vanadium from calcined slag were analyzed to increase the high-value utilization efficiency of double refractory gold deposits. The results showed that the high-temperature chlorination efficiency of gold increased with the increase of calcium chloride dosage. At the same time, the oxidation effect of vanadium in roasting slag is also improved, which reduces the cost of extracting vanadium from roasting slag by acid. the vanadium leaching ratio of 83.3% when the calcium chloride amount of 10%, the roasting temperature of 1000celcius, the roasting time of 240min, and the airflow rate of 1L/min, and the gold volatilization rate of 89.9%. The high-temperature chlorination reaction of gold and the acid leaching reaction of vanadium from calcined slag were also controlled by the interfacial chemical reaction. The apparent activation energy of the high-temperature chlorination of gold and the acid leaching of vanadium from calcined slag is calculated to be E = 71.61kJ/mol and 40.82kJ/mol, respectively. Suggested that gold recovery from vanadium-bearing carbonaceous gold ores was achieved using chlorination heat treatment. Also, the possibility of recovering vanadium from the roasting slag was verified by acid leaching experiments

    Effect of Geobacter metallireducens nanowire on electron transfer efficiency in microbial fuel cell

    No full text
    BACKGROUND To understand the effect of electron shuttle compounds on the electron transfer behavior of MFC and the formation process of microbially fabricated nanowires. In this paper, 2,6-anthraquinone desulfonation (AQDS) and Fe(OH)(3) were used as electron mediator and electron acceptor, respectively, to study the effect of electron mediator on the formation of bio-nanowires during the growth of Geobacter metallireducens in the double chamber MFC reactor (MFC), and the effects of electron transfer efficiency and electrical current characteristic. RESULTS The results show that the culture process of the Geobacter metallireducens with Fe(OH)(3) as an electron acceptor, the reduction product Fe(II) concentration in solution without AQDS was higher than that with AQDS after 10 days due to the formation of microbial nanowires. In comparison, the Pili protein content of the system without AQDS reached 336 ug/mL, which was higher than the AQDS system. Nanowires increased the transfer efficiency between biofilm and electrodes, which increased the maximum output voltage of MFC was 442 mV. CONCLUSION At the same time, it was found by electrochemical measurements that the nanowire biofilm electrode had a huge peak of the cyclic voltammetry curve, a small activation resistance, and a strong current response signal, indicating that the nanowires enhanced the electrochemical activity of the electrode. In addition, an electron transfer medium (AQDS) inhibited the expression of aromatic amino acids, tryptophan, and mtrC. Moreover, it destroyed the overlapping pi-pi orbits of the aromatic parts, resulting in reduced and thinner nanowires and then decreasing the conductivity of synthetic organic materials like metals. (c) 2022 Society of Chemical Industry (SCI)

    Recovery and kinetics of gold and vanadium from vanadium-bearing carbonaceous gold by chlorination roasting-acid leaching

    No full text
    The idle mining or flotation decarburization of vanadium-bearing carbonaceous gold ores polluted the environment and wasted resources. In this paper, the volatilization behavior of calcined gold and the extraction kinetics of vanadium from calcined slag were analyzed to increase the high-value utilization efficiency of double refractory gold deposits. The results showed that the high-temperature chlorination efficiency of gold increased with the increase of calcium chloride dosage. At the same time, the oxidation effect of vanadium in roasting slag is also improved, which reduces the cost of extracting vanadium from roasting slag by acid. the vanadium leaching ratio of 83.3% when the calcium chloride amount of 10%, the roasting temperature of 1000celcius, the roasting time of 240min, and the airflow rate of 1L/min, and the gold volatilization rate of 89.9%. The high-temperature chlorination reaction of gold and the acid leaching reaction of vanadium from calcined slag were also controlled by the interfacial chemical reaction. The apparent activation energy of the high-temperature chlorination of gold and the acid leaching of vanadium from calcined slag is calculated to be E = 71.61kJ/mol and 40.82kJ/mol, respectively. Suggested that gold recovery from vanadium-bearing carbonaceous gold ores was achieved using chlorination heat treatment. Also, the possibility of recovering vanadium from the roasting slag was verified by acid leaching experiments
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