Study on the field propagation of Pteromalus sanjiangyuanicus Yang and its biological control of Gynaephora qinghaiensis

Wang Haizhen,Zhang Jianshuang 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.4

Gynaephora qinghaiensis is an important pest that damages alpine meadow vegetation in Qinghai-Tibet Plateau (QTP) alpine pastoral areas. Pteromalus sanjiangyuanicus Yang is a parasitic natural enemy of pupal G. qinghaiensis. For biological control of G. qinghaiensis, local materials and G. qinghaiensis were used for P. sanjiangyuanicus propagation. Under natural field conditions, P. sanjiangyuanicus were propagated in artificial nests. Propagated P. sanjiangyuanicus were then released into the experimental area, where the G. qinghaiensis density was high, and the biological control effect was evaluated. In the propagation test plot (D), the average P. sanjiangyuanicus parasitism rate was 70.3% (46.3–87.0%). The P. sanjiangyuanicus parasitism rate in the experimental area was significantly higher than that in the control area, and the propagation effect was good. The P. sanjiangyuanicus parasitism rates in the biological control plots (A, B, and C) increased yearly from 2016 to 2019, indicating that the P. sanjiangyuanicus population size in the biological control area increased yearly and that the parasitoid population size effectively increased. From 2016 to 2019, the G. qinghaiensis population decline rates in the biological control plots (A, B and C) were 71.1%, 59.3% and 76.4%, respectively (average 68.9%). The control effects on G. qinghaiensis were 80.9%, 69.9% and 80.3%, respectively (average 77.0%). The results showed that P. sanjiangyuanicus was effective in controlling G. qinghaiensis. This study provides a reference for the large-scale propagation of P. sanjiangyuanicus and the further promotion and application of G. qinghaiensis biological control.

A Virtual Inertia Control Strategy Based on Multi-order lead-lag Compensation

Haizhen Xu,Changzhou Yu,Chun Liu,Qinglong Wang,Xing Zhang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In view of the contradiction between active power steady-state and dynamic characteristics regulation of VSG based on the existing first-order virtual inertia algorithm operating in grid- connected mode and multiparalleled mode, a virtual inertia control strategy based on multi-stage lead-lag compensation is proposed in this paper. By cascading a multi-stage lead-lag link in the first -order virtual inertia forward channel, the control freedom of VSG grid-connected and paralleled system is increased, so that the zero and poles can be freely configured. Furthermore, a firstorder lead-lag link is taken as an example to analyze its effect on the output active power steady-state and dynamic characteristics of VSG grid-connected system and paralleled systems. Through reasonable configuration of the secondorder virtual inertia parameters, the system damping ratio can be increased and the power oscillation can be eliminated while its steady-state characteristics are not changed under the circumstance of a large inertia. Experimental results verify the effectiveness of the proposed strategy.

Stability Comparison of Paralleled String Inverters and Central Inverters in PV System

Changzhou Yu,Haizhen Xu,Chun Liu,Qinglong Wang,Xing Zhang,Fang Liu,Fei Li 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Mega-scale solar projects are turning to string inverters nowadays. Multi-parallel string inverters are employed as the interface to the utility grid, giving rise to potential unstable problems. Aiming at this issue, the relationship between number of inverters, output power and grid impedance is analyzed. Based on this, according to different topology, control structures and filter parameters, four types of Standard Equivalent Model (SEM) for multiinverters system are established. By analyzing the stability margin of the four SEMs and the sensitivity of their control parameters, the difference of stability between the string inverters and the central inverters is compared. Finally, the established SEM and the comparison results of the string and central inverters are verified by simulation and experimental results.

Structure and Performance Characteristics of Saturated Iron-core Superconducting Fault Current Limiter

Niu, Xiaoye,Chen, Zhili,Wang, Haizhen,Chen, Zhifu,Zhang, Lifeng,Niu, Guojun,Hong, Hui,Xin, Ying 대한전기학회 2014 The Journal of International Council on Electrical Vol.4 No.2

Superconducting fault current limiter (SFCL) is a kind of short-circuit current limiting device for power grid. It's a new application of superconducting technology on power equipments. Saturated Iron-core Superconducting fault current limiter (SISFCL) is one of many types of SFCL. It takes the advantage that no quenching occurs in superconducting wires during fault current limiting process. The immediately reacting and fast recovering are also its main characteristics. The structure and function of SISFCL is similar to that of traditional transformer and current limiting reactor respectively. Based on mature technologies on design and manufacture of iron core and windings of transformers, SISFCL could be made at the same voltage level as traditional transformers. But there are also significant differences between them. SISFCL will offer an effective solution to limit short-circuit current in future HV or EHV power systems because of its peculiar structures and properties. In this paper, we introduce the structure and characteristics of the SISFCL developed by Innopower. It may help readers to understand SISFCL and its enormous application value for power grids.

Identification and Characterization of the Replication Region of Virulence Plasmid pEIB202 in Edwardsiella piscicida

( Xinyue Chang ),( Chengli Teng ),( Haizhen Wu ),( Jiang Ye ),( Qiyao Wang ),( Huizhan Zhang ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.8

Edwardsiella piscicida is the causative agent of edwardsiellosis, which has caused enormous economic losses worldwide. In our previous research, an attenuated live vaccine known as WED and based on the virulent strain E. piscicida EIB202 can effectively protect turbots against edwardsiellosis via intraperitoneal injection, while vaccination by immersion exhibits a weaker effect. During the development of the immersion vaccine, we surprisingly found the counts of ΔpEIB202/ EIB202 colonized on zebrafish were 100 times lower than those of EIB202. However, pEIB202 carries 53 predicted ORFs and has several copies in E. piscicida EIB202, impeding the study of its function. Thus, the replication region is located at a 1,980 bp fragment (from 18,837 to 20,816 bp), containing a transcriptional repressor and a replication protein. Moreover, the minimal replication plasmid, named pRep-q77, has low copies in both E. coli and E. piscicida, but is more stable in E. piscicida than in E. coli. This work lays a foundation for further examination of the function of the virulence plasmid pEIB202.

Selection of Stable Reference Genes for Real-Time Quantitative PCR Analysis in Edwardsiella tarda

( Zhongyang Sun ),( Jia Deng ),( Haizhen Wu ),( Qiyao Wang ),( Yuanxing Zhang ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1

Edwardsiella tarda is a gram-negative pathogenic bacterium in aquaculture that can cause hemorrhagic septicemia in fish. Many secreted proteins have already been identified as virulent factors of E. tarda. Moreover, since virulent phenotypes are based on the expression regulation of virulent genes, understanding the expression profile of virulent genes is important. A quantitative RT-PCR is one of the preferred methods for determining different gene expressions. However, this requires the selection of a stable reference gene in E. tarda, which has not yet been systematically studied. Accordingly, this study evaluated nine candidate reference genes (recA, uup, rpoB, rho, topA, gyrA, groEL, rpoD, and 16S rRNA) using the Excel-based programs BestKeeper, GeNorm, and NormFinder under different culture conditions. The results showed that 16S rRNA was more stable than the other genes at different culture growth phases. However, at the same culture time, topA was identified as the reference gene under the conditions of different strains, different culture media, and infection, whereas gyrA was identified under the condition of different temperatures. Thus, in experiments, the expression of gapA and fbaA in E. tarda was analyzed by RT-qPCR using 16S rRNA, recA, and uup as the reference genes. The results showed that 16S rRNA was the most suitable reference gene in this analysis, and that using unsuitable reference genes resulted in inaccurate results.

Magnetic Behaviour of Composites Containing Polyacrylate Coated CoFe₂O₄

Hui Liu,Feng Xu,Liangchao Li,Yuping Wang,Haizhen Qiu 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Flow field characteristics of an agitator system of a large diameter slurry-water shield machine

Junjie Liao,Kun Bai,Yi-Min Xia,Haizhen Li,Xianqiong Zhao,Xuemeng Xiao,Yang Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.4

A numerical model was established for calculation in this study on the basis of the standard k-epsilon turbulence model and the discrete phase model of the Euler-Lagrange equation. Results of the particle image velocimetry experiment were used to verify the reliability of the numerical model. The effects of the rotation speeds, slurry densities, and impeller structures on the flow field characteristics, including velocity distribution, ballast fluidity, and power loss, were also investigated. The results indicate that the increase of rotation speed has little influence on the flow field near the wall and bottom of the agitator, and the agitator performs well when the speed is set between 30 rpm and 40 rpm. The increase of the slurry density will increase the pressure loss between the inlet and the outlet, and it will also increase the load of the agitator. Hence, the slurry density must be less than 1400 kg/m 3 . The baffle can improve the velocity distribution of the flow field and the slag discharge capacity of the agitator.

Transcatheter Arterial Chemoembolization Combined with Interferon-α is Safe and Effective for Patients with Hepatocellular Carcinoma after Curative Resection

Zuo, Chaohui,Xia, Man,Liu, Jingshi,Qiu, Xiaoxin,Lei, Xiong,Xu, Ruocai,Liu, Hanchun,Li, Jianliang,Li, Yongguo,Li, Qinglong,Xiao, Hua,Hong, Yuan,Wang, Xiaohong,Zhu, Haizhen,Wu, Qunfeng,Burns, Michael,Li Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

Objectives: Intrahepatic recurrence is the major cause of death among patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after curative surgical resection. Several approaches have been reported to decrease the recurrence rate. The objective of our study was to compare the clinical effects of transcatheter arterial chemoembolization (TACE) combined with interferon-alpha (IFN-${\alpha}$) therapy on recurrence after hepatic resection in patients with HBV-related HCC with that of TACE chemotherapy alone. Methods: We retrospectively analyzed the data from 228 patients who were diagnosed with HBV-related HCC and underwent curative resection between January 2001 to December 2008. The patients were divided into TACE (n = 126) and TACE-IFN-${\alpha}$ (n = 102) groups for postoperative chemotherapy. The TACE regimen consisted of 5-fluorouracil (5-FU), cisplatin (DDP), and the emulsion mixed with mitomycin C (MMC) and lipiodol. The recurrence rates, disease-free survival (DFS), overall survival (OS), and risk of recurrence were evaluated. Results: The clinicopathological parameters and adverse effects were similar between the 2 groups (P > 0.05). The median OS for the TACE-IFN-${\alpha}$ group (36.3 months) was significantly longer than that of the TACE group (24.5 months, P < 0.05). The 3-and 5-year OS for the TACE-IFN-${\alpha}$ group were significantly longer than those of the TACE group (P < 0.05) and the recurrence rate was significantly lower (P < 0.05). The TACE and IFN-${\alpha}$ combination therapy, active hepatitis HBV infection, the number of tumor nodules, microvascular invasion, liver cirrhosis, and the BCLC stage were independent predictors of OS and DFS. Conclusions: The use of the TACE and IFN-${\alpha}$ combination chemotherapy after curative hepatic resection safely and effectively improves OS and decreases recurrence in patients with HBV-related HCC who are at high risk. Our findings can serve as a guide for the selection of postoperative adjuvant chemotherapy for patients with HBV-related HCC who are at high risk of recurrence.