Vibration analysis and dynamic performance improvement of high-frequency injection method

Peng, Wei,Qiao, Mingzhong,Jiang, Chao,Lu, Xihao,Zhu, Peng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

This paper analyzes and compares the typical rotating high-frequency voltage injection (RTHF) method and the typical pulsating high-frequency voltage injection (PSHF) method in terms of torque ripple and vibration. Analysis and experiment results indicate that the PSHF performs better when it comes to torque pulsation and vibration. In addition, it is more suitable for rim motors which have strict restrictions on vibration. However, the estimated rotor position in PSHF has multiple convergence points. In addition, the filters used in PSHF can degrade the dynamic response of the PMSM sensorless field oriented control (SLFOC) system. An improved PSHF method compensated by Hall signals is proposed to accelerate the estimation process and improve the system stability in the presence of sudden load disturbances. The improved method is verified on an 11 kW rim motor experimental platform.

An Efficient PEG/CaCl2-Mediated Transformation Approach for the Medicinal Fungus Wolfiporia cocos

( Qiao Sun ),( Wei Wei ),( Juan Zhao ),( Jia Song ),( Fang Peng ),( Shao Peng Zhang ),( Yong Lian Zheng ),( Ping Chen ),( Wen Jun Zhu ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.9

Sclerotia of Wolfiporia cocos are of medicinal and culinary value. The genes and molecular mechanisms involved in W. cocos sclerotial formation are poorly investigated because of the lack of a suitable and reproducible transformation system for W. cocos. In this study, a PEG/ CaCl2-mediated genetic transformation system for W. cocos was developed. The promoter Pgpd from Ganoderma lucidum effectively drove expression of the hygromycin B phosphotransferase gene in W. cocos, and approximately 30 transformants were obtained per 10 μg DNA when the protoplast suspension density was 106 protoplasts/ml. However, no transformants were obtained under the regulation of the PtrpC promoter from Aspergillus nidulans.

State-Space Modeling of Grid-Connected Power Converters Considering Power-Internal Voltage Characteristics

Qiao Peng,Yongheng Yang,Frede Blaabjerg 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

To analyze the stability of power electronicsdominated systems, this paper develops a state-space model of power converters including the DC-link voltage control, where the power-internal voltage (PIV) characteristics of the power converters are considered. The PIV concept comes from the inertia characteristic and swing equation of synchronous generators. It reflects the relationship between the output power and converter internal voltage, the converter response to grid disturbances, and finally, the impact of power converters on the grid stability. In the proposed model, the inputs are the outer controller references and the converter output power, i.e., the power at the point of common coupling (PCC). The output of the model is the internal voltage that determines the grid power distribution, including the power at the PCC. The power will be fed back to the converters as an input, and thinks the closed-loop model of the converterbased system is obtained. Importantly, the parameters of the proposed model are independent of the power grid, but related to the converter operation points and parameters. This makes the model more general and can be employed to analyze multiple converter-based systems. Furthermore, a case study is conducted in this paper to demonstrate the model and the stability analysis.

Effect of alcohol dehydrogenase 1C (ADH1C) genotype on vitamin A restriction and marbling in Korean native steers

Dong Qiao Peng,정우석,이재성,김원섭,조용호,김민정,오영근,백열창,황성구,이홍구 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.8

Objective: This work was to find the correlation of alcohol dehydrogenase 1C (ADH1C) genotype with vitamin A reduction and carcass traits during the vitamin A restriction period. Methods: In study 1, 60 Korean native steers were fed a diet (890 IU/kg) with 8,000 IU and 0 IU of supplemental premix vitamin A/kg of dry matter (DM) for control and treatment group, respectively. The levels of serum vitamin A were analyzed through high preparative performance liquid chromatography, and the ADH1C genotype was analyzed based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP; 78.1% TT type, 21.9% TC type); however, CC type was not found. Then, the interaction between ADH1C and carcass traits on the vitamin A restriction was investigated in study 2. A total of 136 Korean native steers were fed a diet that included 930 IU/kg vitamin A of DM. Results: Serum vitamin A in treatment was reduced to 112.4 IU/dL in steers with TT type of ADH1C, while for steers with TC type the concentration of serum vitamin A was dropped to 79.5 IU/dL (p<0.1) in study 1. This showed that TC type had the potential to lower serum vitamin A concentration during vitamin A restriction compared to TT type. In study 2 we found that eye muscle area, marbling and carcass weight in Korean native steers with TC type were higher than in steers with TT type (p<0.05). Conclusion: The interaction between vitamin A restriction and TC type of ADH1C gene could have the potential of increasing the marbling in Korean native steers. These results indicated that steers with TC type of the ADH1C gene were more sensitive to the change of serum vitamin A than TT types. Furthermore, this finding has the potential to enable a higher marbling score under the condition of vitamin A restriction in Korean native steers.

A novel charring agent containing caged bicyclic phosphate and its application in intumescent flame retardant polypropylene systems

Hua-Qiao Peng,Qian Zhou,De-Yi Wang,Li Chen,Yu-Zhong Wang 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.5

A novel charring agent, bis(2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-1-oxo-4-hydroxymethyl) phenylphosphonate (BCPPO), was synthesized and characterized by FT-IR, 1H NMR and 31P NMR spectroscopies. Moreover, the novel charring agent combining with ammonium polyphosphate (APP) as well as melamine (MA) was adopted as intumescent flame retardants (IFR) to impart flame retardance and dripping resistance to polypropylene (PP). Flammability and thermal behaviors of the treated PP were investigated by Limiting Oxygen Index (LOI), Vertical Burning Test (UL-94), Thermogravimetric Analysis (TGA) and Cone Calorimeter test. Results indicate that the intumescent flame retardant with the novel charring agent shows both excellent flame retardance and anti-dripping abilities for PP when the three main components of IFR coexist at appropriate proportions, and the optimum flame retardant formulation is APP:MA:BCPPO = 3:1:1 that gives an LOI of 30.3 and UL- 94 V-0 rating, moreover, both the heat release rate (HRR) and the total heat release (THR) of IFR-PP with the optimum formulation decrease significantly relative to PP from cone calorimeter analysis. The residues from decomposition of the IFR-treated PP was characterized by FT-IR spectroscopy and SEM micrograph, and it was found that the char yield as well as char properties have direct effects on the flame retardance and anti-dripping behaviors of the treated PP.

Friction Stir Processing of Cold-Sprayed High-Entropy Alloy Particles Reinforced Aluminum Matrix Composites: Corrosion and Wear Properties

Peng Han,Jia Lin,Wen Wang,Zhihao Liu,Yating Xiang,Ting Zhang,Qiang Liu,Xiaohu Guan,Ke Qiao,Yingchun Xie,Kuaishe Wang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3

The high-entropy alloy particles reinforced 6061Al composite was prepared by cold spray (CS) and then modified by frictionstir processing (FSP). The microstructure evolutions, corrosion, and wear behaviors of the composites were investigated. Results showed that numerous micro-pores and cracks were distributed in the Al matrix due to adiabatic shear instability andinsufficient deformation of the deposited particles for CSed samples. The average size of uniformly distributed HEA particleswas ~ 24 μm, and the geometric necessary dislocation (GND) density reached 17.1 × 1015m−2 due to large plastic deformationduring CS. Comparatively, the micro-pores and cracks were eliminated, and many fragmented HEA particles dispersed inthe Al matrix with an average size of ~ 4 μm for FSPed sample. Note that the GND density reduced to 9.8 × 1015m−2 due todynamic recrystallization during FSP. The formation rate of the oxide film was gradually greater than that of the dissolutionrate with the samples immersion in 3.5 wt% NaCl solution from 12 to 36 h, and the main corrosion mechanism was particledissolution around micro-pores and pitting for CSed and FSPed samples, respectively. In the polarization process, the FSPedsamples exhibited low corrosion tendency and high corrosion rate due to the dense and uniform microstructure, low GNDdensity, and dispersed HEA particles. The FSPed samples had better wear resistance than the CSed samples at 25 °C and200 °C. The dominant wear mechanisms of CSed and FSPed samples were abrasion at 25 °C, while the wear mechanismsof these samples were adhesion accompanied by abrasion at 200 °C.

Real-Time Surveillance of People on an Embedded DSP-Platform

Qiao, Qifeng,Peng, Yu,Zhang, Dali The Institute of Electronics and Information Engin 2007 JUCT : Journal of Ubiquitous Convergence Technolog Vol.1 No.1

This paper presents a set of techniques used in a real-time visual surveillance system. The system is implemented on a low-cost embedded DSP platform that is designed to work with stationary video sources. It consists of detection, a tracking and a classification module. The detector uses a statistical method to establish the background model and extract the foreground pixels. These pixels are grouped into blobs which are classified into single person, people in a group and other objects by the dynamic periodicity analysis. The tracking module uses mean shift algorithm to locate the target position. The system aims to control the human density in the surveilled scene and detect what happens abnormally. The major advantage of this system is the real-time capability and it only requires a video stream without other additional sensors. We evaluate the system in the real application, for example monitoring the subway entrance and the building hall, and the results prove the system's superior performance.

Enhancing Tensile Properties of Wire-Arc Additively Manufactured Ti-6Al-4 V Deposits Via Cryogenic Vaporised Ar Shielding/Cooling

Peng Han,Jia Lin,Wen Wang,Zhihao Liu,Yating Xiang,Ting Zhang,Qiang Liu,Xiaohu Guan,Ke Qiao,Yingchun Xie,Kuaishe Wang 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

The high-entropy alloy particles reinforced 6061Al composite was prepared by cold spray (CS) and then modified by frictionstir processing (FSP). The microstructure evolutions, corrosion, and wear behaviors of the composites were investigated. Results showed that numerous micro-pores and cracks were distributed in the Al matrix due to adiabatic shear instability andinsufficient deformation of the deposited particles for CSed samples. The average size of uniformly distributed HEA particleswas ~ 24 μm, and the geometric necessary dislocation (GND) density reached 17.1 × 1015m−2 due to large plastic deformationduring CS. Comparatively, the micro-pores and cracks were eliminated, and many fragmented HEA particles dispersed inthe Al matrix with an average size of ~ 4 μm for FSPed sample. Note that the GND density reduced to 9.8 × 1015m−2 due todynamic recrystallization during FSP. The formation rate of the oxide film was gradually greater than that of the dissolutionrate with the samples immersion in 3.5 wt% NaCl solution from 12 to 36 h, and the main corrosion mechanism was particledissolution around micro-pores and pitting for CSed and FSPed samples, respectively. In the polarization process, the FSPedsamples exhibited low corrosion tendency and high corrosion rate due to the dense and uniform microstructure, low GNDdensity, and dispersed HEA particles. The FSPed samples had better wear resistance than the CSed samples at 25 °C and200 °C. The dominant wear mechanisms of CSed and FSPed samples were abrasion at 25 °C, while the wear mechanismsof these samples were adhesion accompanied by abrasion at 200 °C.

Syntrophic Propionate Degradation Response to Temperature Decrease and Microbial Community Shift in an UASB Reactor

( Qiao Ying Ban ),( Jian Zheng Li ),( Li Guo Zhang ),( Ajay Kumar Jha ),( Yu Peng Zhang ),( Bin Ling Ai ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.3

Propionate is an important intermediate product during the methane fermentation of organic matter, and its degradation is crucial for maintaining the performance of an anaerobic digester. In order to understand the effect of temperature on propionate degradation, an upflow anaerobic sludge blanket (UASB) reactor with synthetic wastewater containing propionate as a sole carbon source was introduced. Under the hydraulic retention time (HRT) of 10 h and influent propionate of 2,000 mg/l condition, propionate removal was above 94% at 30-35ºC, whereas propionate conversion was inhibited when temperature was suddenly decreased stepwise from 30ºC to 25ºC, to 20ºC, and then to 18ºC. After a long-term operation, the propionate removal at 25ºC resumed to the value at 30- 35ºC, whereas that at 20ºC and 18ºC was still lower than the value at 35ºC by 8.1% and 20.7%, respectively. Microbial community composition analysis showed that Syntrophobacter and Pelotomaculum were the major propionate-oxidizing bacteria (POB), and most POB had not changed with temperature decrease in the UASB. However, two POB were enriched at 18ºC, indicating they were low temperature tolerant. Methanosaeta and Methanospirillum were the dominant methanogens in this UASB and remained constant during temperature decrease. Although the POB and methanogenic composition hardly changed with temperature decrease, the specific CODPro removal rate of anaerobic sludge (SCRR) was reduced by 21.4%-46.4% compared with the control (35ºC) in this system.

Free-Form Surface Flattening Based on Rigid Registration and Energy Optimization

Peng Wei,Qiao Kai,Bao Yidong,Zhang Chaoyang,Ji Weixi 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.8

Fundamental technology of Computer Aided Design, free-form surface flattening is important for both practical and scientific point of view in mechanical engineering. This paper proposed a flattening algorithm by using a local rigid registration and a global energy optimization. Firstly, each 3D element is aligned to the plane by minimizing the distance between the original 3D element and its corresponding planar element. Then, a global optimization operator is used to stitch and optimize these best-aligned local elements by iteratively minimizing a quadratic energy function composed of linear elastic energy, which makes the internal force of the nodes reach the equilibrium state. The experimental results show that this method is stable and reliable, and can obtain good surface flattening effect under free boundary conditions.