The Biotypes, Wing-forms and the Immigration of Brown Planthopper, Nilaparvata lugens Stal, in Zhejiang Province, China

Yu, Xiaoping,Lu, Zhongxian,Wu, Guorui,Tao, Linyong,Chen, Jianming,Zheng, Xusong,Xu, Hongxing Korean Society of Applied Entomology 2001 Journal of Asia-Pacific Entomology Vol.4 No.2

The virulence change (biotype), wing form development and immigration of brown planthopper (BPH) Nilaparvata lugens Stal, population in Zhejiang province was studied as compared to these BPH populations collected from Guangxi and Yunnan province, China and Philippines. The results indicate that the Zhejiang population could successfully infest variety IR26 and Mudgo after 1989, and ASD7 and IR36 after 1998, showing the characters of BPH biotype 2 and biotypes 3. The BPH tropical populations such as Guangxi population, however, adapted the resistant varieties IR26, Mudgo and ASD7 earlier. In 1997, the nymphal survival indices of Guangxi and Yunnan populations on Rathu Heenati (Bph3) were up to 70.9 and 66.7 respectively, higher than Zhejiang population. The Zhejiang populations show low brachupterous rates and have a negative correlation with nymphal density, belonging to the temperate type. The Philippine populations are almost brachypterous, however, the brachypterous rates of BPH males raise with the increase of nymphal density. The Guangxi population has a high brachypterous rate, being similar to the tropical type. On the other hand, tests showed that the lowest survival rate, longer duration of nymphs and the lightest weight of brachypterous female occurred in the $2^{nd}$ generation of BPH after continuously feeding on resistant variety. Physiologically, the highest activities of superoxide dismutase (SOD) and catalase (CAT) were detected in the second generation of the BPH feeding on resistant rice variety.

Magnetic biochar from alkali-activated rice straw for removal of rhodamine B from aqueous solution

Zhaogang Ren,Fang Chen,Bin Wang,Zhongxian Song,Ziyu Zhou,Dong Ren 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.4

To address organic dye wastewater, economic and effective adsorbents are required. Here, magnetic biochar from alkali-activated rice straw (AMBC) was successfully synthesized using one-step magnetization and carbonization method. The alkaline activation caused the large specific surface area, high pore volume and abundant oxygen-containing groups of the AMBC, and the magnetization gave the AMBC a certain degree of electropositivity and fast equilibrium characteristics. These characteristics collectively contributed to a relative high adsorption capacity of 53.66 mg g<SUP>−1</SUP> for this adsorbent towards rhodamine B (RhB). In brief, RhB can spontaneously adsorb onto the heterogeneous surface of the AMBC and reach the equilibrium in 60 min. Although the initial pH, ionic strength and other substances of the solution affected the adsorption performance of the AMBC, it could be easily regenerated and reused with considerable adsorption content. Based on the results, H-bonds, π–π stacking and electrostatic interactions were speculated as the primary mechanisms for RhB adsorption onto the AMBC, which was also demonstrated by the FTIR analysis. With the advantageous features of low cost, easy separation, considerable adsorption capacity and favorable stability and reusability, the AMBC would be a potential adsorbent for removing organic dyes from wastewater.

An Error Quasi Quadratic Differential Based Event-triggered MPC for Continuous Perturbed Nonlinear Systems

Ning He,Qingqing Chen,Zhongxian Xu,Botao Bai,Chao Shen 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1

A new event-triggered model predictive control (ET-MPC) algorithm is proposed for continuous perturbed nonlinear systems with constraints for the purpose of reducing computing burden and communication transmission. In the first step, an original event triggering condition is constructed based on the slope variation of the state error between the optimal prediction and the real state, i.e., the quasi quadratic differential (QQD) type eventtriggered mechanism. Secondly, the dual-mode control has been adopted to deal with the constrained nonlinear systems subject to disturbances, based on which the execution process of the proposed QQD based ET-MPC is described. In addition, the feasibility of the algorithm and closed-loop stability of the system have been strictly proved in theory. Lastly, two simulation examples are utilized to verify the effectiveness and applicability of the proposed algorithm.

Research for the bearing fit effect on the vibration characteristics of spindle rotor-bearing system

Zhan Wang,Siyang Chen,Wenzhi He,Zinan Wang,Zhongxian Xia 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

Spindle bearing fits mainly include interference fit of inner ring and clearance fit of outer ring, which directly affect the vibration characteristics of spindle rotor-bearing system. In this paper, the influence of spindle bearing inner and outer ring fits on bearing support stiffness is firstly studied. Considering the spindle bearing inner and outer ring fits, a dynamic model of spindle rotor-bearing system is established. Then, the analysis methods of bifurcation and time domain are used to perform simulation analysis. The influence of bearing fit on the vibration characteristics of rotor system is researched. Lastly, at different rotating speeds, bearing fits experiments are conducted on built motorized spindle test platform, which verifies the correctness of the dynamic model. The results show that the influence of bearing fit on vibration is nonlinear. The influence of clearance fit on vibration is smaller, when the clearance fit value of bearing outer ring is about 4-6 μm. The vibration characteristics of rotor are more sensitive to the clearance fit of bearing outer ring than the interference fit of bearing inner ring. The research work provides an important theoretical basis for the optimal of spindle bearing assembly.

Research on Partial Discharge Pattern Recognition in GIS Based on EFPI Sensor

Wang Zan,Liu Zhongquan,Qiao Lili,Qian Dingdong,Chen Zhongxian,Gao Chaofei,Wang Wei 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

An EFPI fber optic ultrasonic sensor can be used for the detection and pattern recognition of partial discharge ultrasonic signals in Gas Insulated Switchgear. Compared with traditional piezoelectric sensors, it has many advantages, such as high sensitivity and strong anti-interference ability. Based on this, four typical PD models of the tip, metal particles, suspension and creeping surface were set up in the GIS cavity flled with 0.4 MPa SF6 gas, and the EFPI sensor was innovatively used to detect the discharge ultrasonic signal and extract the single ultrasonic pulse signal. The waveform features form a feature parameter database, and the probabilistic neural network algorithm and the support vector machine algorithm are used for pattern recognition and comparative analysis, respectively. The ultrasonic signal detected by the EFPI sensor has prominent features. On the basis of extracting the feature parameters, the two pattern recognition algorithms can achieve an average recognition rate of more than 85%, and the recognition efect of the support vector machine is better than that of the probabilistic neural network

Juvenile hormone-mediated reproduction induced by a sublethal concentration of imidacloprid in Cyrtorhinus lividipennis (Hemiptera: Miridae)

Jun Zhu,Yao Li,Ying-Ying Tang,Jian-Qi Liu,Yi-Yu Chen,Zhongxian LV,Fang Liu 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.1

The Hemipteran predator, Cyrtorhinus lividipennis, feeds on the eggs and nymphs of rice planthoppers and leafhoppers. We previously demonstrated that sublethal concentrations of imidacloprid stimulated the reproduction of C. lividipennis. Considering the essential roles of juvenile hormone (JH) in insect reproduction, we speculated that sublethal concentrations of imidacloprid may stimulate the reproduction of C. lividipennis by regulating JH level. To test this, we cloned C. lividipennis JH acid methyl transferase (ClJHAMT) and JH esterase (ClJHE), which are responsible for JH biosynthesis and degradation genes, respectively. We then knocked down ClJHAMT by injecting dsRNA into C. lividipennis nymphs and found that emerging female adults exhibited 88.8% lower expression of the vitellogenin gene (ClVg) and the number of eggs was reduced by 41.5% as compared with controls. Silencing ClJHE increased ClVg mRNA expression by 275.0% but did not affect fecundity. A sublethal concentration of imidacloprid (LC 20 ) increased the JH titer in females by 35.3% and 60.6% at 24 and 48 h post-emergence, respectively. In treatments containing both imidacloprid and dsJHAMT, the silencing of CLJHAMT reduced the number of eggs produced by adult females by 21.4% as compared to the control (imidacloprid + dsGFP). Our results indicated that sublethal concentration of imidacloprid may induce C. lividipennis reproduction by upregulating JH level via JHAMT. The finding could provide valuable information for improved integration of C. lividipennis and insecticides in pest management.