Load Power Estimation Based Secondary Control for Microgrids

Teng Wu,Jinjun Liu,Zeng Liu,Shike Wang,Baojin Liu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The well-known active power-frequency and reactive power-voltage amplitude droop control is widely used in the coordinative control of parallel inverters in microgrids. However, this conventional droop method may cause frequency and voltage deviation, which affects the accuracy of power supply. This paper proposes a novel secondary control strategy to compensate this deviation. This strategy mimics the Master-Slave control but requires no communication lines among the parallel inverters. The master inverter adopts conventional droop method (using power to control frequency and voltage amplitude) and is controlled as a voltage source while the slave inverters adopt reversed droop method (using frequency and voltage amplitude to control power) and are controlled as current sources. The droop characteristic bias of slave inverters is designed online based on the estimation of load power demand. Through this method, frequency and voltage deviation can be eliminated and power sharing can be realized among all the slave inverters. Simulation and experimental results are provided to prove the effectiveness of the proposed control strategy.

Wolbachia infection in six species of gall wasps and their parasitoids

Zhao Gao-Zhi,Zhu Teng-Ran,Zeng Yang,Zhu Dao-Hong 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Wolbachia are endosymbiotic bacteria that are widely present in nematodes and arthropods and sometimes have a significant impact on the evolution, ecology, and biology of their hosts. The co-occurrence of Wolbachia within both Cynipid gall wasps and their parasitoids has rarely been studied. In this study, we report the occurrence of six species of gall wasps and 10 species of their parasitoids in central China. Wolbachia detection using the wsp gene showed that Wolbachia infected two species of gall wasps as well as their parasitoids, indicating that horizontal transmission of Wolbachia occurs between gall wasps and their parasitoids. Given that parasitoids will kill their hosts, Wolbachia may be horizontally transferred from gall wasps to their parasitoids. Using multilocus sequence typing (MLST) analysis, five new strains of Wolbachia were identified, all of which belonged to su pergroup A. The strains of Wolbachia that infected gall wasps were not the same as those that infected their parasitoids. This result indicated that Wolbachia may evolve independently in parasitoids after they have been transferred from the host gall wasps.

PR and Harmonic Compensation Control Scheme with Current State Feedback for an Single-Phase Active Voltage Quality Regulator

Ye Zhuhuan,Xiao Guochun,Zeng Zhong,Teng Guofei,Jia Yaoqin 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In this paper, a new control scheme of a proportional resonant (PR) + harmonic compensation (HC) combined with inductor current state feedback and load current feed-forward for an Active Voltage Quality Regulator is proposed. The inductor current state feedback is used to enhance the stability and increase the damping factor to eliminate the resonant peak of output LC filter. The load current feed forward is implemented to compensate the voltage drop due to the inductor state feedback and suppress the load disturbance. Meanwhile, a combined PR and HC control structure is added into the outer voltage regulation loop to achieve zero steady-state error and compensate harmonics respectively. Theoretical analysis has been achieved and the analytical results are validated by simulation studies and experimental tests on a single-phase 2㎸A prototype, which verify the feasibility and effectiveness of the proposed controller.

Comparison of structural features and in vitro digestibility of purple yam (Dioscorea alata L.) resistant starches by autoclaving and multi-enzyme hydrolysis

Li, Tao,An, Fengping,Teng, Hui,Huang, Qun,Zeng, Feng,Song, Hongbo 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.1

Resistant starches (RS) were prepared from purple yam by dual autoclaving-retrogradation (DAS), and pullulanase debranching treatment (PDS). DAS and PDS were then hydrolyzed by ${\alpha}-amylase$ and amyloglucosidase to obtain DAS.H and PDS.H. Differences in structural characteristics and in vitro digestibility among the four samples were investigated. The results showed that granules of RS had a rough surface and irregular shape. DAS had the lowest amylose content (29.52%), whereas PDS.H had the highest amylose content (41.96%). The order of crystallinity of the RS was: PDS.H (31.23%) > DAS.H (30.16%) > PDS (21.23%) > DAS (15.30%). Analysis by in vitro digestibility indicated a decreased hydrolysis index and glycemic index due to lower swelling power and water-binding capacity, and a well-ordered double helix structure and more crystallization in PDS.H than in the other RS samples. These results suggest that pullulanase debranching combined with ${\alpha}-amylase$ and amyloglucosidase hydrolysis may produce better RS with improved crystalline structure and higher digestion resistibility.

Detection of Spinal Muscular Atrophy Using a Duplexed Real-Time PCR Approach With Locked Nucleic Acid-Modified Primers

Pan Jianyan,Zhang Chunhua,Teng Yanling,Zeng Sijing,Chen Siyi,Liang Desheng,Li Zhuo,Wu Lingqian 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder mainly caused by homozygous deletions that include exon 7 of the survival motor neuron 1 (SMN1) gene. A nearby paralog gene, SMN2, obstructs the specific detection of SMN1. We optimized a duplexed real-time PCR approach using locked nucleic acid (LNA)-modified primers to specifically detect SMN1. Methods: An LNA-modified primer pair with 3´ ends targeting SMN1 specific sites c.835-44g and c.840C was designed, and its specificity was examined by real-time PCR and Sanger Sequencing. A duplexed real-time PCR approach for amplifying SMN1 and control gene albumin (ALB) was developed. A randomized double-blind trial with 97 fresh peripheral blood samples and 25 dried blood spots (DBS) was conducted to evaluate the clinical efficacy of the duplexed approach. This new approach was then used to screen 753 newborn DBS. Results: The LNA-modified primers exhibited enhanced specificity and 6.8% increased efficiency for SMN1 amplification, compared with conventional primers. After stabilizing the SMN1 test by optimizing the duplexed real-time PCR approach, a clinical trial validated that the sensitivity and specificity of our new approach for detecting SMA patients and carriers was 100%. Using this new approach, 15 of the screened 753 newborns were identified as carriers via DBS, while the rest were identified as normal individuals. These data reveal a carrier rate of 1.99% in Hunan province, South Central China. Conclusions: We have developed a novel, specific SMN1 detection approach utilizing real-time PCR with LNA-modified primers, which could be applied to both prenatal carrier and newborn screening.

The Combination of Platelet Rich Plasma Gel, Human Umbilical Mesenchymal Stem Cells and Nanohydroxyapatite/polyamide 66 Promotes Angiogenesis and Bone Regeneration in Large Bone Defect

Liu Wei,Huang Yong,Liu Daqian,Zeng Teng,Wang Jingzhe,Li Ang,Wang Dawei,Wang Xiaoyu 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.6

BACKGROUND: In the present study, a novel tissue engineering bone graft including platelet rich plasma gel (PRP gel), human umbilical mesenchymal stem cells (HUMSCs) and nanohydroxyapatite/polyamide 66 (nHA-PA66) was constructed. We explored whether the composite scaffolds could enhance the angiogenesis and bone repair capacity in rat femoral large bone defect (LBD). This study aimed to provide evidence for the clinical application of the composite scaffold in LBD treatment. METHODS: PRP was prepared, the platelets and growth factors were measured. HUMSCs were isolated and identified. the osteogenic capacity of PRP in vitro was measured. Then HUMSCs-PRP-gel/nHA-PA66 composite scaffolds were synthesized and observed. The proliferation and osteogenesis differentiation of HUMSCs on the composite scaffold was measured. The angiogenic capacity of PRP in vitro was measured by capillary-like tube formation assay. Finally, the angiogenesis and bone repair capacity of the composite scaffolds was measured in rat LBD. RESULTS: PRP contained high level of platelets and growth factors after activation, and promoted osteogenic and angiogenic differentiation in vitro. The HUMSCs-PRP-gel/nHA-PA66 composite scaffold was porosity and promoted the proliferation and osteogenesis differentiation of HUMSCs. At 12th weeks, more micro-vessels and new bone were formed around the composite scaffolds compared with other groups, the defect was almost repaired. CONCLUSION: Our study for the first time identified that the combination of PRP gel, HUMSCs and nHA-PA66 scaffold could significantly promote angiogenesis and bone regeneration in rat LBD, which may have implications for its further application in clinical LBD treatment.

Effect of silicon carbide on carbonization and morphology behavior of coal tar pitch

Wenjuan Zhang,Shihua Song,Xianren Zeng,Genhui Teng,Qi Wang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.10

Coal tar pitch (CTP) is a quite promising candidate for the production of carbon materials. However, the application of CTP is restricted by its poor properties at elevated temperature. In this paper, silicon carbide was used to modify CTP and thecarbonization and morphology behavior of CTP and the CTP modified with silicon carbide were studied by thermogravimetry and differential scanning calorimetry (TG-DSC), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show silicon carbide and CTP can coalesce well when the ratio of silicon carbide to CTP is 12% and the carbonization yield of CTP at 900 o C increases from 35.86% to 40.56% after the modification of CTP. Further, the addition of silicon carbide to CTP can reduce the temperature at which the reaction of thermal polymerization happen during the carbonization process of CTP and can facilitate the carbonization of CTP. In addition, little pore distributes on the surface of the heat-treatment products after the modification of CTP with silicon carbide.

Comparison of structural features and in vitro digestibility of purple yam (Dioscorea alata L.) resistant starches by autoclaving and multi-enzyme hydrolysis

Tao Li,Fengping An,Hui Teng,Qun Huang,Feng Zeng,Hong-bo Song 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.1

Resistant starches (RS) were prepared from purple yam by dual autoclaving-retrogradation (DAS), and pullulanase debranching treatment (PDS). DAS and PDS were then hydrolyzed by a-amylase and amyloglucosidase to obtain DAS.H and PDS.H. Differences in structural characteristics and in vitro digestibility among the four samples were investigated. The results showed that granules of RS had a rough surface and irregular shape. DAS had the lowest amylose content (29.52%), whereas PDS.H had the highest amylose content (41.96%). The order of crystallinity of the RS was: PDS.H (31.23%)[DAS.H (30.16%)[PDS (21.23%)[DAS (15.30%). Analysis by in vitro digestibility indicated a decreased hydrolysis index and glycemic index due to lower swelling power and water-binding capacity, and a well-ordered double helix structure and more crystallization in PDS.H than in the other RS samples. These results suggest that pullulanase debranching combined with a-amylase and amyloglucosidase hydrolysis may produce better RS with improved crystalline structure and higher digestion resistibility.

Biological Approaches to Treating Intervertebral Disk Degeneration: Devising Stem Cell Therapies

Han, Inbo,Ropper, Alexander E.,Konya, Deniz,Kabatas, Serdar,Toktas, Zafer,Aljuboori, Zaid,Zeng, Xiang,Chi, John H.,Zafonte, Ross,Teng, Yang D. Cognizant Communication Corp. 2015 CELL TRANSPLANTATION Vol.24 No.11