Experimental Study on Interaction between Slurry and Soil on Excavation Face of Shield in Sand Stratum

Jiahua Mao,Dajun Yuan,Binghui Wang,Shengnan Liu,Liping Chen 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

In sandy soil, the timely and effective formation of a filter cake is crucial for maintaining the stability of the excavated face during slurry shield tunnelling. Obtaining real-time information on slurry infiltration and particle migration is challenging, which greatly impacts the formation of the filter cake. Real-time monitoring of slurry infiltration and particle deposition is achieved through the use of electrical resistivity and pore water pressure measurements of the soil. It has been discovered that the primary pathway for slurry infiltration is inevitable in sandy soil, and it is crucial to take note of the persistent slurry leakage resulting from this situation in the shield excavation face. The distribution of slurry particle deposition is highly non-uniform in the penetration direction, with the maximum particle deposition occurring at the slurry-soil interface. However, this deposition is susceptible to disturbance from shield cutting tools, which can compromise the safety of the excavation face. Even if the particle size of the slurry is smaller than the pore size of the sand stratum, the slurry with higher viscosity can still form an internal filter cake. Furthermore, the research indicates that slurry infiltration can induce regular changes in soil electrical resistivity.

Low Chattering Trajectory Tracking Control of Non-singular Fast Terminal Sliding Mode Based on Disturbance Observer

Jiqing Chen,Chaoyang Zhao,Qingsong Tang,Xu Liu,Zhikui Wang,Chengzhi Tan,Jiahua Wu,Teng Long 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2

The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified. The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified.

A differential pumping system for the gas attenuator of SXFEL

Junnan LIU,Jiahua CHEN,Chaofan XUE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Response of egg-pupal parasitoid Fopius arisanus (Sonan) to infochemicals from the host eggs' surface of Bactrocera dorsalis (Hendel)

Qinge Ji,Kang Bi,Jiahua Chen 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.4

To determine host-related infochemicals that facilitate contact between the egg-pupal parasitoid, Fopius arisanus (Sonan), and its host, Bactrocera dorsalis (Hendel), we analyzed the volatiles on the surface of B. dorsalis eggs by hydrocarbon profiling of the hexane extracts using Gas Chromatography–Mass Spectrometry (GC–MS). These analyses resulted in the identification of 12 components from the egg surface. Among these 6 were alkanes (Dodecane, Heneicosane, Docosane, Tricosane, Tetracosane and Pentacosane) and the proportion was 42.79%, 1 was a fatty acid (Palmitic acid) and the proportion was 3.88%, 3 were fatty acid derivatives (Dodecanoic acid methylester, Lauric acid ethyl ester and Ethyl tetradecanoate) and the proportion was 45.92%, and 2 were alcohols (Tetradecanol and Hexadecanol) and the proportion was 7.41%. 9 chemicals were chosen from the above 12 components to study the EAG and behavioral responses of male and female F. arisanus. The results showed that the EAG and behavioral responses of F. arisanus to same chemical had similar trends, and both EAG relative values and lure rates of females were higher than males' generally. However, for Dodecane and Tetracosane the EAG relative values and lure rates showed extremely significant differences between males and females respectively, for Tricosane there was significant difference, for Ethyl tetradecanoate there was no significant difference between males and females of the relative EAG values but of the lure rates there was significant difference. The resultsmaybe provide new insights fromthe chemical relationship between parasitoid and host to biocontrol B. dorsalis using F. arisanus.

Effects of Co-60 radiation on the activities of three main antioxidant enzymes in Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

Pumo Cai,Jingfang Hong,Cong Wang,Yanchuan Yang,Chuandong Yi,Jiahua Chen,Qinge Ji 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

Co-60 radiation has been broadly used for pest management because it results in male sterility and a lack ofemergence of unparasitized hosts due to oxidative damage. Insect life is significantly affected by abiotic stressfactors, including Co-60 radiation. In the present study, we determined the influence of Co-60 radiation on animportant pest in southern China, the oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae). We exposed 30-h-old B. dorsalis eggs to Co-60 radiation at doses of (0, 5, 10, 15, 20, 25, 30, 35, and 40 Gy) and determined theactivity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). CAT andPOX activity significantly increased in B. dorsalis in the 1st larvae instar after high-intensity radiation doses(25–40 Gy) and played an important role in the antioxidant response to intensive radiation. The activity of POXin B. dorsalis at the 2nd larval instar sharply decreased after different doses of radiation, except for 10 and 40 Gy. Our results demonstrated that Co-60 radiation affected the activity of antioxidant enzymes and disturbed thephysiology of B. dorsalis, especially at early stages (the 1st, 2nd larvae instar). These three antioxidant defenseenzymes cooperatively play an important role in protecting B. dorsalis from oxidative damage.

Senwot Wharton, a new genus for the Oriental region with description of two new species from Thailand (Hymenoptera: Braconidae: Alysiinae)

Junli Yao,Cornelis van Achterberg,Michael J. Sharkey,Eric G. Chapman,Jiahua Chen 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.1

SenwotWharton 1983, is a small braconid genus with only two previously described species. The genus is revised using morphological characters and a phylogenetic analysis of COI sequence. Senwot Wharton is reported for the first time from Thailand and two new species: Senwot yinxianggaoae Yao n. sp. and Senwot jiyuanyaoi Yao n. sp. are described and illustrated. A key to species of the genus Senwot is presented.

The miR-145-5p/CD36 pathway mediates PCB2-induced apoptosis in MCF-7 cells

Yuan Yuan,Caihua Xue,Qiang Wu,Mengjie Wang,Jiahua Liu,Longfei Zhang,Qianwen Xing,Jingyan Liang,Hua Wu,Zhi Chen 한국유전학회 2021 Genes & Genomics Vol.43 No.2

Background Procyanidin B2 (PCB2) can increase the levels of anti-infammatory and immune mediators. Objectives However, its molecular mechanism in human breast cancer remains unclear. This study aimed to investigate the antitumor efect of PCB2 on MCF-7 cells and to examine the underlying mechanism. Methods The fow cytometry and EdU incorporation assays were measured the PCB2-induced BMECs. The expression levels of infammatory factors and immune response genes were upregulated in MCF-7 cells, high-throughput sequencing was used to detect diferentially expressed genes in blank and PCB2-treated MCF-7 cells. Results The results showed that PCB2 induced the apoptosis of MCF-7 cells. CD36 profles were afected in MCF-7 cells. Additionally, prediction software identifed a miR-145-5p binding site in the CD36 sequence. Luciferase reporter assays and Western blot analysis were used to verify the regulatory relationships between the diferentially expressed miRNA miR145-5p and CD36. MiR-145-5p and its key target (CD36) constitute a potential miRNA-mRNA regulatory pair. Functional studies in MCF-7 cells revealed that CD36 promotes but miR-145-5p inhibits apoptosis. Conclusion Overall, these data suggest that miR-145-5p inhibits the enhancing efect of PCB2 on CD36 expression by binding CD36 and subsequently regulating apoptosis, the immune response and anti-infammatory pathways. These results provide theoretical and experimental support for the treatment of breast cancer.