Experimental Study on the Bearing Characteristics of Rigid-Flexible Long-Short Pile Composite Foundations in Thick Collapsible Loess Areas

Fei Gao,Xuansheng Cheng,Wenfang Wang,Qingfeng Lv,Xiangjun Cheng 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.5

The bearing and deformation characteristics of embankments with rigid-flexible long-short pile composite foundations (RLPCFs) in thick collapsible loess strata are not yet accurately understood. In this study, a large-scale field experiment was conducted, and screw (long) and compaction (short) piles were employed to reinforce a section of the foundation of the Lanzhou-Zhangye high-speed railway in thick collapsible loess. The pile load transfer, foundation settlement, pile-soil stress distribution, and load sharing characteristics were analyzed to reveal the bearing properties of the composite foundation. The results show that negative friction arises along the upper part of the pile, and the neutral points of the short pile and long pile are located at 2/5 and 1/3 down the pile lengths, respectively. The short pile eliminates the collapsibility of the shallow loess and enhances the foundation’s bearing capacity. The long pile transfers the load of the shallow foundation and pile top to the deep foundation through lateral friction, which reduces the settlement of the shallow foundation. When the soil arch in the embankment is fully formed, the short pile bears approximately 20% of the load, while the long pile and the soil between piles bear 80%. With the increase in embankment filling height, the load borne by the long pile rises, and the load borne by the soil between piles decreases gradually. The top settlement of the cross-section of the composite foundation is distributed in a concave basin shape, and the maximum settlement occurs in the center of the embankment. The parameters of the short pile can be obtained on the basis of the collapsibility grade and bearing capacity of the loess foundation, the length and area replacement rate of the long pile can be obtained based on the settlement control requirements of the superstructure of the composite foundation, and the lateral friction of the long pile can be increased by increasing the roughness of the pile and setting the screw.

Synthesis and Properties of Arylacetylene Resins with Siloxane Units

Fei Gao,Lingling Zhang,Lemin Tang,Jian Zhang,Yan Zhou,Farong Huang,Lei Du 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

A series of arylacetylene resins with siloxane units were synthesized by the condensation reactions of m-diethynylbenzene magnesium reagents with various α,ω-bis(chloro)dimethylsiloxanes. These resins are liquids and are miscible with common organic solvents at room temperature. The structures of the resins were characterized by FT-IR, 1H NMR,13C NMR, 29Si NMR, and gel permeation chromatography (GPC). The thermal behaviors of the resins were examined with differential scanning calorimetry (DSC). These resins have good processability. They can be thermally crosslinked through the ethynyl groups to produce cured resins. The thermal and thermooxidative stabilities of the cured resins were studied by thermogravimetric analysis (TGA). The cured resins possess high thermal and thermooxidative stability. Their decomposition occurs at above 500 oC in both N2 and air. With increasing the length of siloxane units in the resins, the thermal stability of the cured resins decreases in N2. When the cured resins were sintered above 1450 oC under argon, hard and glassy SiOC ceramics were obtained. These SiOC ceramics have the decomposition temperatures at 5% weight loss above 800 oC in air.

Synthesis and Properties of Arylacetylene Resins with Siloxane Units

Gao, Fei,Zhang, Lingling,Tang, Lemin,Zhang, Jian,Zhou, Yan,Huang, Farong,Du, Lei Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

A series of arylacetylene resins with siloxane units were synthesized by the condensation reactions of m-diethynylbenzene magnesium reagents with various $\alpha,\omega$-bis(chloro)dimethylsiloxanes. These resins are liquids and are miscible with common organic solvents at room temperature. The structures of the resins were characterized by FT-IR, $^1H$ NMR, $^{13}C$ NMR, $^{29}Si$ NMR, and gel permeation chromatography (GPC). The thermal behaviors of the resins were examined with differential scanning calorimetry (DSC). These resins have good processability. They can be thermally cross-linked through the ethynyl groups to produce cured resins. The thermal and thermooxidative stabilities of the cured resins were studied by thermogravimetric analysis (TGA). The cured resins possess high thermal and thermooxidative stability. Their decomposition occurs at above $500^{\circ}C$ in both $N_2$ and air. With increasing the length of siloxane units in the resins, the thermal stability of the cured resins decreases in $N_2$. When the cured resins were sintered above $1450^{\circ}C$ under argon, hard and glassy SiOC ceramics were obtained. These SiOC ceramics have the decomposition temperatures at 5% weight loss above $800^{\circ}C$ in air.

Clinical Efficacy of Endoscopic Pancreatic Drainage for Pain Relief with Malignant Pancreatic Duct Obstruction

Gao, Fei,Ma, Shuren,Zhang, Ning,Zhang, Yingchun,Ai, Meina,Wang, Bing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Objective: This study was conducted to investigate the efficacy of pancreatic drainage for pain relief in advanced pancreatic cancer. Method: Seventy-one patients with pancreatic carcinoma were divided into two groups: dilated and non-dilated pancreatic ducts. All patients underwent endoscopic retrograde cholangiopancreatography (ERCP), endoscopic biliary stenting and pancreatic stenting. Visual Analog Scale (VAS) scores, pain remission rates and survival time were evaluated during follow-up. Results: The post-ERCP VAS score of the dilated group was lower than that of the non-dilated group at 1 and 3 months post-ERCP. There was no difference at 6 months. The pain remission rate in the dilated duct group was significantly higher than that in non-dilated duct group in 1 and 3 months post-ERCP. The median survival times were 8.17 and 8.22 months respectively. Conclusion: Endoscopic pancreatic drainage can relieve pain of advanced pancreatic cancer accompanied by safe dilation of the pancreatic duct.

Constitutive Modeling and Dynamic Softening Mechanism During Hot Deformation of an Ultra-Pure 17%Cr Ferritic Stainless Steel Stabilized with Nb

Fei Gao,Zhenyu Liu,R. D. K. Misra,Haitao Liu,Fuxiao Yu 대한금속·재료학회 2014 METALS AND MATERIALS International Vol.20 No.5

The hot deformation behavior of an ultra-pure 17%Cr ferritic stainless steel was studied in the temperaturerange of 750-1000 °C and strain rates of 0.5 to 10 s1 using isothermal hot compression tests in a thermomechanicalsimulator. The microstructural evolution was investigated using electron backscattered diffractionand transmission electron microscopy. A modified constitutive equation considering the effect of strain onmaterial constant was developed, which predicted the flow stress for the deformation conditions studied, exceptat 950 °C in 1 s1 and 900 °C in 10 s1. Decreasing deformation temperature and increasing strain was beneficialin refining the microstructure. Decreasing deformation temperature, the in-grain shear bands appeared inthe microstructure. It is suggested that the dynamic softening mechanism is closely related to deformationtemperature. At low deformation temperature, dynamic recovery was major softening mechanism and no dynamicrecrystallization occurred. At high deformation temperature, dynamic softening was explained in terms ofefficient dynamic recovery and limited continuous dynamic recrystallization. A drop in the flow stress wasnot found due to very small fraction of new grains nucleated during dynamic recrystallization.

Biotransformation, a Promising Technology for Anti-cancer Drug Development

Gao, Fei,Zhang, Jin-Ming,Wang, Zhan-Guo,Peng, Wei,Hu, Hui-Ling,Fu, Chao-Mei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

With the high morbidity and mortality caused by cancer, finding new and more effective anti-cancer drugs is very urgent. In current research, biotransformation plays a vital role in the research and development of cancer drugs and has obtained some achievements. In this review, we have summarized four applications as follows: to exploit novel anti-cancer drugs, to improve existing anti-cancer drugs, to broaden limited anti-cancer drug resources and to investigate correlative mechanisms. Three different groups of important anti-cancer compounds were assessed to clarify the current practical applications of biotransformation in the development of anti-cancer drugs.

What Can the Shanghai Cooperation Organization and China Bring to Post-2014 Afghanistan?

( Gao Fei ),( Xiao Yu ) 경남대학교 극동문제연구소 2014 ASIAN PERSPECTIVE Vol.38 No.4

Amid the reduction of US forces in Afghanistan, the search for solutions to the Afghanistan security conundrum calls for regional coordination. Despite limited achievements in the past, the Shanghai Cooperation Organization (SCO) may be an important contributor to stability in Afghanistan. The SCO brings together powerful regional players (Russia and China) and important neighboring states whose strategic interests are intertwined in Afghanistan. All of them are potential stakeholders in providing regional solutions. In this article we suggest that the role of the SCO would lie in not only regionalizing Afghanistan policymaking but also promoting the country’s integration into a regional framework of common interests.

CircCEP85 upregulates IGF1 expression to promote breast cancer progression via sponging miR‑1193

Gao Fei,Han Jianjun,Jia Li,He Jun,Wang Yun,Chen Mi 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.4

Background: Increasing evidence has suggested that circular RNAs (circRNAs) play critical roles in breast cancer (BC) progression. However, the expression level and potential functional role of circRNA centrosomal protein 85 (circ- CEP85) in BC remains largely unknown. Here, we aimed to explore the role of circCEP85 in BC. Methods: The levels of circCEP85, insuline-like growth factor I (IGF1) mRNA and microRNA-1193 (miR-1193) were examined by quantitative real-time polymerase chain reaction. The protein level was measured by Western blot. Cell proliferation, migration, apoptosis, angiogenesis and stemness were assessed by cell counting kit-8, 5-ethynyl- 2’-deoxyuridine assay, transwell assay, flow cytometry, tube formation and sphere formation assays. Xenograft mouse models were conducted to evaluate the effect of circCEP85 in BC in vivo. Moreover, dual-luciferase reporter, RNA pulldown, and RNA immunoprecipitation (RIP) assays were preformed to confirm the interaction between miR-1193 and circCEP85 or IGF1. Results: CircCEP85 was upregulated in BC tissues and cells. Silencing of circCEP85 inhibited proliferation, invasion, angiogenesis and stemness, but promoted apoptosis in BC cells in vitro. In addition, circCEP85 silencing inhibited tumor growth in vivo. Mechanistically, circCEP85 elevated IGF1 expression via sponging miR-1193 to promote breast cancer progression. Conclusion: The circCEP85-miR-1193-IGF1 axis regulated BC progression via the competitive endogenous RNA (ceRNA) mechanism. CircCEP85 might be a prognostic biomarker and therapeutic target for BC.

Cooperative Learning Control of Unknown Nonlinear Multi-agent Systems with Time-varying Output Constraints Using Neural Networks and Barrier Lyapunov Functions via Backstepping Design

Fei Gao,Sizhe Zheng 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

The existing research on cooperative learning is incapable of ensuring the physical constraints of the systems, resulting in possible damage to the plants. The purpose of this study is to present a cooperative learning control method for multi-agent systems with time-varying output constraints. The backstepping technique is used to design the controller by introducing time-varying barrier Lyapunov functions (BLFs) and radial basis function (RBF) neural networks (NNs). Contrary to previous results, the use of BLFs ensures that time-varying output constraints are never violated during the learning control process. The controller for the same plant is designed using the RBF NN approximation of unknown dynamic functions of the plants along the union orbit of all agents. By utilizing a previously learned RBF NN, the control performance is improved and the computational load is reduced. Finally, a numerical example is given to show the tracking performance with time-varying output constraints, the learning ability of RBF NNs, and the improved performance of the control system with learned RBF Nns.

RNAi-Mediated Gene Silencing of Trcot1 Induces a Hyperbranching Phenotype in Trichoderma reesei

Fei Gao,Mengzhu Li,Weiquan Liu,Yingguo Bai,Tu Tao,Yuan Wang,Jie Zhang,Huiying Luo,Bin Yao,Huoqing Huang,Xiaoyun Su 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.2

Trichoderma reesei is the major filamentous fungus used to produce cellulase and there is huge interest in promoting its ability to produce higher titers of cellulase. Among the many factors affecting cellulase production in T. reesei, the mycelial phenotype is important but seldom studied. Herein, a close homolog of the Neurospora crassa COT1 kinase was discovered in T. reesei and designated TrCOT1, which is of 83.3% amino acid sequence identity. Functional disruption of Trcot1 in T. reesei by RNAi-mediated gene silencing resulted in retarded sporulation on potato dextrose agar and dwarfed colonies on minimal medium agar plates containing glucose, xylan, lactose, xylose, or glycerol as the sole carbon source. The representative mutant strain, SUS2/Trcot1i, also displayed reduced mycelia accumulation but hyperbranching in the MM glucose liquid medium, with hyphal growth unit length values decreased to 73.0 μm/tip compared to 239.8 μm/tip for the parent strain SUS2. The hyperbranching phenotype led to slightly but significantly increased cellulase secretion from 24 to 72 h in a batch culture. However, the cellulase production per unit of mycelial biomass was much more profoundly improved from 24 to 96 h.