Decoupling Analysis of Interaction between Tunnel Surrounding Rock and Support in Xigeda Formation Strata

Ping Zhou,Feicong Zhou,Jiayong Lin,Jinyi Li,Yifan Jiang,Bao Yang,Zhijie Wang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

The Xigeda Formation has the characteristics of poor cementation, variable structure, and softening in water. It is prone to lead to failure of the initial support structures, arch collapse, and even roof fall. The key to the problem lies in the exploration of the interaction between surrounding rock and support. Therefore, based on the constraint loss theory of the tunnel face space effect, this paper constructively introduces multiple dependent variables, including the intermediate principal stress, the dilatancy of the surrounding rock, the timeliness of the shotcrete support stiffness, and the water content of the Xigeda formation, to decouple the whole process of the interaction between the surrounding rock and support, and discusses the influence of each variable. The research results show that: i) there is a critical support point in the tunnel under the influence of the unified strength theoretical parameter b and water content, and when the unified strength theoretical parameter b is constant, the critical distance of the support will decrease with the increase of the water content; ii) from the perspective of deformation control, the stress of support structure will increase with the increase of dilatancy angle of Xigeda surrounding rock; iii) considering the hardening characteristics of shotcrete, the initial support stiffness of Xigeda tunnel increases nonlinearly, and the whole process of stress and deformation can be divided into four stages; iv) the combined support structure of section steel and grille has little difference in the deformation control effect of the surrounding rock and the stress of the support structure, but the combined support structure of the grille steel frame is more sensitive to the hardening parameters.

Key Parameters Design Method of AGF Method for Metro Connecting Passage in Water-Rich Coastal Area

Feicong Zhou,Ping Zhou,Jinyi Li,Tiancheng Ge,Jiayong Lin,Zhijie Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

Artificial Ground Freezing Method (AGF) is an efficient, environmentally friendly reinforcement method for the construction of metro connecting passage in water-rich and weak stratum. The core of AGF is the design of frozen wall thickness and freezing temperature. In order to obtain the quantitative relationship between the freezing temperature and the frozen wall thickness, this study firstly equates the frozen wall to a rectangular frame mechanical model based on the stress state of the frozen wall formed by AGF. And then the calculation method of frozen wall thickness based on strength conditions is obtained by theoretical estimation. Furthermore, based on the relationship between the strength of the frozen soil and the freezing temperature obtained from the experiment, the freezing temperature and the frozen wall thickness are related to propose a frozen wall thickness design method considering the freezing temperature. In addition, experimental studies revealed that the compressive strength and shear strength of frozen soil increase linearly as the freezing temperature decreases. Secondly, the lower the freezing temperature, the smaller the frozen wall thickness required. Notably, the relationship between the frozen wall thickness and freezing temperature formed by the AGF method can be obtained through the design method proposed in this paper. Taking actual case as an example, when the frozen wall thickness is selected from 1.2 to 2.2 m, the required freezing temperature range is (-5) to (-25)oC. Finally, the feasibility of the designed freezing parameters in the connecting passage construction is verified through numerical simulation and field measurement, which shows that the design method has a promotion prospect.

A New Combined Support Technology to Prevent the Failure of the Existing Metro Station Induced by Unilateral Excavation

Feicong Zhou,Wenhao Fan,Ping Zhou,Mao Chen,Shougen Chen,Zhijie Wang,Yifan Jiang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

This study establishes a 3-D simulation model based on a real project, which reveals the problem that the metro structure deformation induced by unilateral excavation without any support exceeds the safety threshold. According to the metro structure deformation warning area, this study proposes a support technology that combines cover plate braces and diagonal steel braces. The research shows that the lateral deformation reduction ratio of the metro station under the diagonal steel brace is about 10% − 20%. The deformation reduction ratio under the cover plate brace is about 35% − 40%. To ensure construction safety, this study adopts the optimal support combination of 3 cover plates and 6+9+11 steel pipes. Monitoring feedback and simulation prediction shows that the comprehensive support system can reduce structural deformation by 56.1%, and effectively control the deformation within a safe range.

Improved Received Signal Strength Ratio Based High Accuracy Indoor Visible Light Positioning Scheme

Zhijie Luo,JinHua Wang,WenWen Zhao,JianKun Luo,WeiNan Zhang,GuoFu Zhou 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.12

With the increasingly development of Light-emitting Diode (LED) lighting, in this paper, we proposed an Indoor Visible Light Positioning (VLP) Scheme by using visible LED lights for accurate localization. The basic idea of the position scheme is to improve received signal strength ratio algorithm. Received signal strength ratio (RSSR) is the relative ratio of optical powers detected between each LED and optical receiver. In this paper, we introduce concept of multiple LEDs selection to improve RSSR positioning algorithm. By three LEDs are reasonably selected from the multiple LEDs deployed in the room, the positioning accuracy of RSSR is improved. The system can be employed easily because it does not require additional sensors and occlusion problem in visible light would be alleviated. In addition, we performed the simulation experiments, and confirmed the feasibility of our proposed method.

Discussion and Design of Dynamic Liquid Level Intelligent Monitoring System

Guangdong Qiu,Zhijie Luo,Guofu Zhou 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.11

The problem of how to calculate the height of the liquid level under tilting status is considered. A custom algorithm for obtaining the real height of liquid level according to the difference of distance measured by ultrasonic sensors is proposed. A set of intelligent monitoring system is designed as well. The system, which takes S3C6410 processor as the control core of the front-end system, measures distance by multiple HC-SR04 ultrasonic sensors, compensates temperature via external temperature sensor ds1820, collects data via inserting driver modules, and then gets the liquid level angle by means of the difference between distance, to calculate the liquid level height, both of which will be sent via Bluetooth chip CC2541 and wireless network. The data, received by PC, will be used for graphical interface display and speech broadcasting depending on Processing software programming. The smart phone can also read data and control devices from the front-end. The results of simulation experiment of this system are considered.

A Risk Prediction Model for Invasive Fungal Disease in Critically Ill Patients in the Intensive Care Unit

Fangyi Li,Minggen Zhou,Zijun Zou,Weichao Li,Canxia Huang,Zhijie He 한국간호과학회 2018 Asian Nursing Research Vol.12 No.4

Purpose: Developing a risk prediction model for invasive fungal disease based on an analysis of the disease-related risk factors in critically ill patients in the intensive care unit (ICU) to diagnose the invasive fungal disease in the early stages and determine the time of initiating early antifungal treatment. Methods: Data were collected retrospectively from 141 critically ill adult patients with at least 4 days of general ICU stay at Sun Yat-sen Memorial Hospital, Sun Yat-sen University during the period from February 2015 to February 2016. Logistic regression was used to develop the risk prediction model. Discriminative power was evaluated by the area under the receiver operating characteristics (ROC) curve (AUC). Results: Sequential organ failure assessment (SOFA) score, antibiotic treatment period, and positive culture of Candida albicans other than normally sterile sites are the three predictors of invasive fungal disease in critically ill patients in the ICU. The model performs well with an ROC-AUC of .73. Conclusion: The risk prediction model performs well to discriminate between critically ill patients with or without invasive fungal disease. Physicians could use this prediction model for early diagnosis of invasive fungal disease and determination of the time to start early antifungal treatment of critically ill patients in the ICU.

Study on the neutron imaging detector with high spatial resolution at China spallation neutron source

Jiang, Xingfen,Xiu, Qinglei,Zhou, Jianrong,Yang, Jianqing,Tan, Jinhao,Yang, Wenqin,Zhang, Lianjun,Xia, Yuanguang,Zhou, Xiaojuan,Zhou, Jianjin,Zhu, Lin,Teng, Haiyun,Yang, Gui-an,Song, Yushou,Sun, Zhiji Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

Gadolinium oxysulfide (GOS) is regarded as a novel scintillator for the realization of ultra-high spatial resolution in neutron imaging. Monte Carlo simulations of GOS scintillator show that the capability of its spatial resolution is towards the micron level. Through the time-of-flight method, the light output of a GOS scintillator was measured to be 217 photons per captured neutron, ~100 times lower than that of a ZnS/LiF:Ag scintillator. A detector prototype has been developed to evaluate the imaging solution with the GOS scintillator by neutron beam tests. The measured spatial resolution is ~36 ㎛ (28 line pairs/mm) at the modulation transfer function (MTF) of 10%, mainly limited by the low experimental collimation ratio of the beamline. The weak light output of the GOS scintillator requires an enormous increase in the neutron flux to reduce the exposure time for practical applications.

Beyond Canonical PROTAC: Biological targeted protein degradation (bioTPD)

Huifang Wang,Runhua Zhou,Fushan Xu,Kongjun Yang,Liuhai Zheng,Pan Zhao,Guangwei Shi,Lingyun Dai,Chengchao Xu,Le Yu,Zhijie Li,Jianhong Wang,Jigang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential to modulate disease associated proteins that have previously been considered undruggable, by employing the host destructionmachinery. The exploration and discovery of cellular degradation pathways, including but not limited toproteasomes and lysosome pathways as well as their degraders, is an area of active research. Since the conceptof proteolysis-targeting chimeras (PROTACs) was introduced in 2001, the paradigm of TPD has been greatlyexpanded and moved from academia to industry for clinical translation, with small-molecule TPD being particularlyrepresented. As an indispensable part of TPD, biological TPD (bioTPD) technologies including peptide-, fusionprotein-, antibody-, nucleic acid-based bioTPD and others have also emerged and undergone significantadvancement in recent years, demonstrating unique and promising activities beyond those of conventional small molecule TPD. In this review, we provide an overview of recent advances in bioTPD technologies, summarize theircompositional features and potential applications, and briefly discuss their drawbacks. Moreover, we present somestrategies to improve the delivery efficacy of bioTPD, addressing their challenges in further clinical development.

Fatigue properties of the pantograph–insulator system of metro trains: Experiments and the design for improvement

Fang Jia,Fengyu Xu,Zhijie Xia,Hang Zhou,Defeng Zhang 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

The power of a metro vehicle is supplied by the pantograph on the vehicle roof. During pantograph lifting, the insulator set of the pantograph is prone to fracture caused by the impact load. In this work, a Single-arm pantograph–insulator system (SPIS) of metro vehicles was studied for the fatigue fracture of the insulator set induced by impact load. The basic structure of the SPIS was first introduced. The dynamic axial force test and fatigue and fracture damage experiments was then conducted on SPIS for both simulation experiment platform and real vehicles to analyze the causes of the insulator fracture. A method to improve the design structure of the back-end insulator set was proposed to resolve the problems of both the impact failure of the insulator steel core and the stress concentration on the interface between a steel core and an epoxy resin. The finite element analysis results indicated that the improved insulator set shows a much smaller stress concentration. Therefore, the improved insulator set has a greatly reduced fatigue damage subjected to shear effect, which validated the feasibility of the improved structure design.

Modeling and Optimization Method of Laser Cladding Based on GA-ACO-RFR and GNSGA-II

Guohua He,Yanbin Du,Qiang Liang,Zhijie Zhou,Linsen Shu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.5

Laser cladding is an environmentally friendly and reliable surface modification technology. The quality characteristics of the coating are directly affected by the process parameters of laser cladding. The reasonable selection of process parameters is essential to obtain high-quality coating. In this study, the single-track 15-5PH alloy coating was fabricated on the surface of 12Cr13 stainless steel. In view of the hybrid Genetic Algorithm and Ant Colony Optimization (GA-ACO) can effectively improve the prediction ability and robustness of Random Forest Regression (RFR), a prediction method of cladding layer quality characteristics based on GA-ACO-RFR was proposed. The fast non-dominated ranking genetic algorithm with elite strategy by introducing the Gaussian distribution crossover operator (GNSGA-II) was used to optimize the process parameters of laser cladding. The results showed that the multi-objective optimization method of laser cladding process parameters proposed in this paper can obtain high-quality laser cladding coating. This work demonstrated the potential of the proposed method in laser cladding process prediction and optimization.