A Novel Zero-Sequence Current Elimination PWM Scheme for an Open-Winding PMSM With Common DC Bus

This paper introduces a novel pulse width modulation (PWM) scheme for an OW-PMSM driven by dual two-level three-phase inverter with common dc bus which can effectively deal with the inherent zero-sequence current (ZSC) problem. Based on conventional symmetrical unipolar double frequency SPWM scheme with appropriate phase-shift, the common mode voltage (CMV) of two inverters can keep the same and cancel out each other to eliminate the modulated zero sequence voltage (ZSV) disturbance source. In this case, the double frequency effect can be retained to reduce the ac side current ripple and suppress both the corresponding motor vibration and acoustic noise which is advantageous to improve the synthetic performance of motor. The DC bus voltage utilization of the novel PWM scheme is proved to reach the maximum value as same as the conventional modulated ZSV elimination scheme. Meanwhile, a zero-sequence controller is designed to suppress ZSC by further adjusting the two CMVs to counteract other zero-sequence disturbance sources. To verify the analysis, the proposed PWM technique associated with the control method is implemented in an OW-PMSM experimental setup to validate the superiority of proposed method

Dissecting the mechanism of the nonheme iron endoperoxidase FtmOx1 using substrate analogues

FtmOx1 is a nonheme iron (NHFe) endoperoxidase, catalyzing three disparate reactions, endoperoxidation, alcohol dehydrogenation, and dealkylation, under in vitro conditions; the diversity complicates its mechanistic studies. In this study, we use two substrate analogues to simplify the FtmOx1-catalyzed reaction to either a dealkylation or an alcohol dehydrogenation reaction for structure-function relationship analysis to address two key FtmOx1 mechanistic questions: (1) Y224 flipping in the proposed COX-like model vs α-ketoglutarate (αKG) rotation proposed in the CarC-like mechanistic model and (2) the involvement of a Y224 radical (COX-like model) or a Y68 radical (CarC-like model) in FtmOx1-catalysis. When 13-oxo-fumitremorgin B (7) is used as the substrate, FtmOx1-catalysis changes from the endoperoxidation to a hydroxylation reaction and leads to dealkylation. In addition, consistent with the dealkylation side-reaction in the COX-like model prediction, the X-ray structure of the FtmOx1•CoII•αKG•7 ternary complex reveals a flip of Y224 to an alternative conformation relative to the FtmOx1•FeII•αKG binary complex. Verruculogen (2) was used as a second substrate analogue to study the alcohol dehydrogenation reaction to examine the involvement of the Y224 radical or Y68 radical in FtmOx1-catalysis, and again, the results from the verruculogen reaction are more consistent with the COX-like model.R24 GM134210 - NIGMS NIH HHSPublished versio

Asymmetric giant magnetoresistance in Co10Cu90 magnetic granular alloys

We have observed a type of giant magnetoresistance (GMR) in magnetic granular Co10Cu90 alloys. The asymmetric GMR depends strongly on the size of magnetic Co particles, which exhibit superparamagnetic behavior at given measured temperature. The asymmetric GMR points to a metastable state that develops when the sample is field-cooled, which is lost after recycling. We propose that high-field cooling produces more effective parallel alignment of small unblocked Co particle moments and interfacial magnetizations, which contributes to the further decrease of the resistance in comparison with the samples zero-field-cooled, and then applied to the same field

Enhanced activity of tungsten modified CeO2/TiO2 for selective catalytic reduction of NOx with ammonia

A series of W-doped CeO2/TiO2 catalysts prepared by different impregnation methods assisted with ultrasonic energy were investigated for the selective catalytic reduction (SCR) of NOx (NO and NO2) by NH3 The activity of the CeO2/TiO2 catalyst was enhanced by the addition of W with all the methods, while the promotional effect was pronounced for catalyst prepared by co-impregnation method. The catalytic activity of 10% CeO2/TiO2 (CeTi) was greatly enhanced by the addition of 6%WO3 in the broad temperature range of 200-500 degrees C BET, XRD, XPS and TPD methods revealed that the co-impregnation method could make CeO2 and WO3 crystallites disperse better over the catalyst surface, and much stronger interaction happened between Ce and W for the more appearance of Ce3+. The addition of tungsten could bring mole ad-NOx and ad-NH3 adsorption species, and simultaneously enhanced the catalytic activity for NH3-SCR of NOx (C) 2010 Elsevier B V All rights reserve

J. Alloy. Compd.

Hexagonal hydroxyapatite (HAP) has been successfully synthesized by using EDTA as chelate under hydrothermal condition. The as-prepared samples were characterized by SEM and XRD. The XRD result indicated that the products were preferentially oriented along c-axis. The SEM photographs showed that the size of the crystals was well controlled by the reaction parameters such as temperature, pH value, reaction time and the mole ratio of EDTA/Ca. (C) 2007 Elsevier B.V. All rights reserved.Hexagonal hydroxyapatite (HAP) has been successfully synthesized by using EDTA as chelate under hydrothermal condition. The as-prepared samples were characterized by SEM and XRD. The XRD result indicated that the products were preferentially oriented along c-axis. The SEM photographs showed that the size of the crystals was well controlled by the reaction parameters such as temperature, pH value, reaction time and the mole ratio of EDTA/Ca. (C) 2007 Elsevier B.V. All rights reserved

Asymmetric giant magnetoresistance in Co10Cu90 magnetic granular alloys

We have observed a type of giant magnetoresistance (GMR) in magnetic granular Co10Cu90 alloys. The asymmetric GMR depends strongly on the size of magnetic Co particles, which exhibit superparamagnetic behavior at given measured temperature. The asymmetric GMR points to a metastable state that develops when the sample is field-cooled, which is lost after recycling. We propose that high-field cooling produces more effective parallel alignment of small unblocked Co particle moments and interfacial magnetizations, which contributes to the further decrease of the resistance in comparison with the samples zero-field-cooled, and then applied to the same field

Catal. Today

A study on the removal of cadmium ions from aqueous solutions by synthetic hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2), HAP) with different morphologies was conducted in batch conditions. The influence of different sorption parameters, such as equilibration time, initial concentration of metal ion, the amount of HAP, pH value of solution and the specific surface area on the sorption amount of Cd(2+) were studied and discussed. Our experimental results are in agreement with pseudo-second-order kinetic equation. The Freundlich and Langmuir adsorption isotherms, often used to describe the sorption of solutes from a liquid phase, can be applied to our experimental results. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, X(m), was found to be 260.42 mg/g. The sorption amount of Cd(2+) increased as the pH value enhanced from 5 to 8. The ion-exchange mechanism and surface complex mechanism may both exist in the adsorption process. Nearly linear dependence between Cd(2+) sorption amount and specific surface area within a certain range has been confirmed. Cd(2+) desorption amount decreased with the increasing pH value of the extracting solution. (C) 2008 Elsevier B.V. All rights reserved.A study on the removal of cadmium ions from aqueous solutions by synthetic hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2), HAP) with different morphologies was conducted in batch conditions. The influence of different sorption parameters, such as equilibration time, initial concentration of metal ion, the amount of HAP, pH value of solution and the specific surface area on the sorption amount of Cd(2+) were studied and discussed. Our experimental results are in agreement with pseudo-second-order kinetic equation. The Freundlich and Langmuir adsorption isotherms, often used to describe the sorption of solutes from a liquid phase, can be applied to our experimental results. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, X(m), was found to be 260.42 mg/g. The sorption amount of Cd(2+) increased as the pH value enhanced from 5 to 8. The ion-exchange mechanism and surface complex mechanism may both exist in the adsorption process. Nearly linear dependence between Cd(2+) sorption amount and specific surface area within a certain range has been confirmed. Cd(2+) desorption amount decreased with the increasing pH value of the extracting solution. (C) 2008 Elsevier B.V. All rights reserved

Hierarchical Hydroxyapatite Microspheres Composed of Nanorods and Their Competitive Sorption Behavior for Heavy Metal Ions

Hydroxyapatite (HAP) microspheres composed of nanorods have successfully been prepared by a facile co-precipitation method without any template. We propose the formation mechanism of the microspheres to be a four-step process on the basis of the evolution of their morphology as a function of reaction time. We investigate the competitive sorption of the HAP microspheres for Pb2+, Cu2+, Cd2+, Zn2+, and Ni2+ to show that HAP microspheres are a highly selective adsorbent for Pb2+ in wastewater

Effects of progressive body-weight versus barbell back squat training on strength, hypertrophy and body fat among sedentary young women

Abstract The objective of this study was to compare the effects of progressive bodyweight training and barbell back squat on muscle strength, muscluar hypertrophy, and body fat percentage in sedentary young women. Thirteen sedentary young women (aged 19.77 ± 0.83 years, height 164.91 ± 6.01) were randomly assigned to either the progressive bodyweight group (n = 6, consisting of 10 levels of movements progressing from bilateral to unilateral) or the barbell squat group (n = 7, 60–80% 1RM). Both groups underwent two training sessions per week for 6 weeks. Measurements of muscle strength (isokinetic knee extensor and flexor muscle peak torque of each leg), muscle thickness (gluteus maximus, rectus femoris, and gastrocnemius muscles), and body fat percentage were taken at baseline and post-testing. Both groups showed a significant increase in isometric peak torque of the knee extensor and flexor (p  0.05) or in the mean concentric peak torque of the knee H/Q ratio (p > 0.05). Both groups also showed significant increases in muscle thickness (p  0.05). The percentage of body fat significantly decreased in the barbell group (pre: 28.66 ± 4.58% vs post: 24.96 ± 5.91%, p = 0.044), but not in the bodyweight group (pre: 24.18 ± 4.63% vs post: 24.02 ± 4.48%, p = 0.679). Our findings indicate that while both training methods increased maximum strength and muscle mass, barbell back squat training may be more effective in reducing body fat percentage