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Hydroxyapatite (HA) has good biocompatibility, high strength and low fracture toughness. It is often used as the main material for artificial bones in bioceramics because of the similar composition. In this study, we prepared zinc-doped hydroxyapatite by the co-precipitation method to produce artificial bone material has antibacterial properties, for use in post joint surgery to inhibit bacterial infection or proliferation and ultimately the incidence of osteomyelitis. The co-precipitation method prepared hydroxyapatite with different concentrations of zinc chloride. The experimental results revealed that after sintering, it has some new phases generated of ZnO and CaZn2(PO4)2 when we add zinc chloride that concentration reaches 0.15 M. The minimum inhibition zone revealed the antibacterial ability of Zinc-HA increased when the concentration of zinc chloride increased from 0.0125 M to 0.15 M. The granulated powder of zinc-doped hydroxyapatite was coated on the titanium substrate by the flame-spraying method. The Zinc-HA coating was found with good biocompatibility and antibacterial ability in the biological and antibacterial test.

Our study aimed to understand the characteristics of ventilator dependence in patients at a respiratory care center and the potential effects of physical therapy on ventilator weaning and patients' functional status. Prospective data collection consisted of the following: (1) demographic data, including name, gender, age, diagnosis, the Acute Physiology and Chronic Health Evaluation as a severity of the disease, modified Glasgow Coma Scale, mobility at the time of admission, and days of hospitalization; (2) Rapid shallow breathing index (RSBI) as a predictive indicator of ventilator weaning, including indicators of ventilator weaning were collected from the respiratory flow sheet; and (3) Barthel index. Between July 1 and December 31, 2007, 126 patients were admitted to the respiratory care center, and those who required mechanical ventilation for more than 14 days were enrolled. Fifty-five subjects received physical therapy. The RSBI in patients who received physical therapy was 75.7 +/- 37.9 before therapy and 80.0 +/- 48.5 afterwards, while the Barthel index increased from 0.8 +/- 1.4 to 1.9 +/- 2.5 (p < 0.05). The RSBI decreased as time of physical therapy lengthened, but not significantly (r = 0.12, p = 0.44). The success rate of ventilator weaning in patients receiving physical therapy intervention versus non-physical therapy intervention was 58.2% and 40.9%, respectively. The results indicated that lengthening the physical therapy intervention time enhanced the ventilator weaning success rate while mobility was not affected (r = -0.11, p = 0.41). Physical therapy may be offered to ventilator-dependent patients in line with their individual needs to improve or maintain basic mobility.

Unintentional series and/or parallel resonances, due to the tuned passive filter and the line inductance, may result in severe harmonic distortion in the industrial power system. This paper presents a hybrid active filter to suppress harmonic resonance and to reduce harmonic distortion. The proposed hybrid filter is operated as variable harmonic conductance according to the voltage total harmonic distortion; therefore, harmonic distortion can be reduced to an acceptable level in response to load change or parameter variation of the power system. Since the hybrid filter is composed of a seventh-tuned passive filter and an active filter in series connection, both dc voltage and kVA rating of the active filter are dramatically decreased compared with the pure shunt active filter. In real application, this feature is very attractive since the active power filter with fully power electronics is very expensive. A reasonable tradeoff between filtering performances and cost is to use the hybrid active filter. Design consideration are presented, and experimental results are provided to validate effectiveness of the proposed method. Furthermore, this paper discusses filtering performances on line impedance, line resistance, voltage unbalance, and capacitive filters.

The electric vehicles become an alternative to gasoline driven cars nowadays which calls for the technological progress on EV battery charger. This paper presents a bidirectional isolated Dual-Active-Bridge-based DC/DC converter with dual-phase-shift control for a Li+Fe battery system of the EV application. The dual-phase-shift control strategy provides two degree of freedom to control the transmitting power and improve the performance of the DAB converter. In order to reduce the switching loss and the hysteresis loss of the isolating transformer, the control strategy is designed to minimize the peak transferring current flowing on the transformer. Theoretical analysis and control implementation are described. A LABVIEW-based prototype is established to verify effectiveness.

This paper presents a control strategy of hybrid active filter for continuous reactive power compensation. The hybrid active filter operates as an equivalent adjustable capacitor in series to the filter inductor. The equivalent capacitance can be tuned to specific value without connecting extra capacitors. When the equivalent capacitor varies, the characteristic of circuit will be modified, including the resonance frequency of the passive filter. Theoretical analysis and experimental results are given to verify effectiveness.

This paper presents a control strategy of hybrid active filter for compensation of the three-phase three-wire industrial power system considering unbalanced loading. In addition to harmonic current compensation, the hybrid filter is designed to compensate both positive- and negative-sequence reactive power based on the so-called instantaneous power theory. Therefore, the compensated system behaves as a resistive network even in a reactive, nonlinear, or unbalanced circuit. Theoretical analysis and experimental results are given to verify effectiveness of the proposed method.

An ADALINE-based DSTATCOM is presented to compensate a distributed generation system. Based on the well-known LMS algorithm, the targeted compensating current of the DSTATCOM can be produced with help of unit positive-sequence voltage vector. Thus, the compensated system current becomes balanced and active, even in a reactive, unbalanced, distorted, and distributed-generator including network. Theoretical analysis and control implementation are detailed. Experimental results from a three-level neutral point-clamped (NPC) inverter validate effectiveness.

Active front-end converters with bidirectional power flow capability have been extensively used for utility applications of power electronics, in which the hybrid type with copupling capacitor in series connection is receiving much attention due to its low operating voltage and low switching ripples. This paper proposes an improved control strategy for hybrid active front-end converters in grid-connected applications. Real power of the converter are controlled by adjusting the reactive current, while reactive power delivered to the power system is dependent on the real current of the converter. Due to series-connected capacitor, the converter can be operated between a low-voltage dc side and high-voltage grid side without any low-frequency transformer. Operation principles are explained in detail, and computer simulations and experimental results are provided to validate the effectiveness of the proposed approach.

Severe harmonic distortion, due to unintentional series or parallel resonance of the passive filters or power factor correction capacitors, is a significant issue in the industrial power system. The transformerless hybrid active filter, which operates at reduced kVA rating and switching ripples, is a promising filtering solution in high-power applications. This paper presents resonant current regulation for the transformerless hybrid active filter to enhance its suppressing capability of harmonic resonances. The proposed current regulator is composed of various band-pass filters in parallel connection to resonate at harmonic frequencies for accurately controlling the active filter as variable harmonic conductance. The current tracking capability of the active filter and the associated damping performance can be improved without increasing overall gain of controller. Therefore, the harmonic resonance can be definitely avoided and the damping conductance can be dynamically adjusted to conform with the harmonics limitation. In addition, the required damping conductance to maintain the harmonic voltage at an allowable level is reduced, compared with proportional control only. Operational principles are detailed and computer simulations are provided to validate the effectiveness of the proposed approach.

Harmonic voltage amplification, due to unintentional series or parallel resonance of power factor correction capacitors, is a significant issue in the industrial power system. Conventional active filters intended to compensate the harmonic current producing by nonlinear loads would not be an effective solution in this scenario, and the harmonic voltage may still be significant. This paper proposes a hybrid active filter to suppress the harmonic resonance in industrial facilities. The hybrid active filter, which is composed of a capacitor and an active filter in series connection, operates as variable harmonic conductance with dynamically tuning characteristic according to the voltage total harmonic distortion, so the damping performance of the active filter can be adjusted in response to load change and power system variation. Therefore, the harmonic resonance would be avoided as well as harmonic voltage distortion can be maintained at an allowable level. Compared with the pure shunt active filter, the dc bus voltage of the proposed hybrid filter is dramatically reduced since the grid voltage is supported by the series capacitor. This feature provides a vital advantage of the active filter, in terms of both the kVA rating and the switching ripples. Operation principles are explained in detail, and computer simulations validate the effectiveness of the proposed approach.

A home area network (HAN) incorporating a high-power high-efficiency charging/discharging battery system is capable of executing energy saving strategies in the smart grid, such as TOU or DR. This paper presents a bidirectional isolated DAB-based DC/DC converter for a Li+Fe battery system in the HAN. Battery energy is controlled by the phase angle between the primary bridge and the secondary bridge of the converter. Theoretical analysis and control implementation are described. A LABVIEW-based prototype is established to verify effectiveness.

The hybrid active front-end converter, which is composed of a capacitor and a voltage source converter in series connection, has been presented recently. Compared with grid-connected converter, the hybrid converter could be operated with reduced dc voltage as well as small-sized passive filters due to series-connected capacitor. This paper presents a power flow control method for a hybrid active front-end converter. Real power of the converter is controlled by the output voltage vector perpendicular to the grid voltage, whereas reactive power of the converter is determined by the output voltage vector parallel to the grid voltage. By dynamically adjusting voltage vector, power conversion between low-voltage dc side, such as PVs or batteries, and high-voltage grid side could be accomplished with no low-frequency transformer required. In addition, a harmonic resistance is emulated in the proposed method to avoid inrush current flowing into the converter due to unintentional voltage spike coming from the power system. Operation principles are explained in detail, followed by both computer simulations and experimental results validating effectiveness.