Sub-level Classification and Prediction System of Fully Weathered Red Sandstone Rock Mass Based on Physical Property Indices

Haiyan Xu,Zimeng Shao,Zhijie Wang,Libin Cai,Zhen Li,Xinzheng Jiang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

This paper intends to obtain a sub-level classification of fully weathered red sandstone rock mass during the Cretaceous period based on physical property indices. An automatic prediction system for mechanical properties of rock mass is also established in which the values of rock mass grade and mechanical properties can be returned when physical indices are given. In this study, water content, relative compaction, and fine content, which are relatively easy to measure on tunnel sites, are selected as physical property indices, while cohesion, internal friction angle, and compression modulus, which affect mechanical strength, are taken as mechanical indices. For the convenience of analysis, rock mass of different physical states is divided into 18 different combinations based on the results of lab tests and rock mass stability of each state is evaluated using a stability evaluation criterion we put forward. The numerical simulation of tunnel excavation is further carried out for determining the sub-level classification. A decision tree model is applied for further studying the relationship between physical and mechanical indices to ensure accurate prediction. The result shows that the prediction system works with high accuracy and can be used for engineering reference for fully weathered red sandstone rock mass.

Context-based compression of point cloud octree structure

Haiyan Xu(허해연),Seung-ho Lee(이승호),Yousun Park(박유선),Euee S. Jang(장의선) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

In this paper, we propose a context-based efficient octree structure compression method to efficiently compress the geometry data of point cloud. Recently, the compression of (static and dynamic) point clouds is gaining more attention as new media applications include point clouds as an important asset. In MPEG, an exploration activity to exploit the feasibility of defining a new standard for point cloud compression has been active for several years. In this paper, we proposed an extended method from MPEG Point Cloud Compression (PCC) that exploits the octree structure (e.g. leaf/non-leaf nodes) to further increase the compression efficiency compared to the existing MPEG method. Through the experiments, the proposed method further reduced the compression ratio up to 7% on average.

RIS Selection and Energy Efficiency Optimization for Irregular Distributed RIS-assisted Communication Systems

Xu Fangmin,Fu Jinzhao,Cao HaiYan,Hu ZhiRui 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.7

In order to improve spectral efficiency and reduce power consumption for reconfigurable intelligent surface (RIS) assisted wireless communication systems, a joint design considering irregular RIS topology, RIS on-off switch, power allocation and phase adjustment is investigated in this paper. Firstly, a multi-dimensional variable joint optimization problem is established under multiple constraints, such as the minimum data requirement and power constraints, with the goal of maximizing the system energy efficiency. However, the proposed optimization problem is hard to be resolved due to its property of nonlinear nonconvex integer programming. Then, to tackle this issue, the problem is decomposed into four sub-problems: topology design, phase shift adjustment, power allocation and switch selection. In terms of topology design, Tabu search algorithm is introduced to select the components that play the main role. For RIS switch selection, greedy algorithm is used to turn off the RISs that play the secondary role. Finally, an iterative optimization algorithm with high data-rate and low power consumption is proposed. The simulation results show that the performance of the irregular RIS aided system with topology design and RIS selection is better than that of the fixed topology and the fix number of RISs. In addition, the proposed joint optimization algorithm can effectively improve the data rate and energy efficiency by changing the propagation environment.

Effects of Antioxidant Tempol on Systematic Inflammation and Endothelial Apoptosis in Emphysematous Rats Exposed to Intermittent Hypoxia

Haiyan Zhao,Yaping Zhao,Xin Li,Leiqian Xu,Fangxin Jiang,Wanju Hou,Lixia Dong,Jie Cao 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.9

Purpose: Obstructive sleep apnea and chronic obstructive pulmonary disease are independent risk factors of cardiovascular disease(CVD), and their coexistence is known as overlap syndrome (OS). Endothelial dysfunction is the initial stage of CVD; however,underlying mechanisms linking OS and CVD are not well understood. The aim of this study was to explore whether OS canlead to more severe inflammation and endothelial apoptosis by promoting endothelial dysfunction, and to assess the interventioneffects of antioxidant tempol. Materials and Methods: Male Wistar rats (n=66) were exposed to normal oxygen [normal control (NC) group], intermittent hypoxia(IH group), cigarette smoke (CH group), as well as cigarette smoke and IH (OS group). Tempol intervention was assessed inOS group treated with tempol (OST group) or NaCl (OSN group). After an 8-week challenge, lung tissues, serum, and fresh bloodwere harvested for analysis of endothelial markers and apoptosis. Results: The levels of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, and apoptosis in circulating epithelialcells were the highest in OS group and the lowest in NC group. These levels were all greater in IH group than in CH group,and were lower in OST group than in OS and OSN groups (all p<0.001). Conclusion: Synergistic effects of IH with cigarette smoke-induced emphysema produce a greater inflammatory status and endothelialapoptosis. OS-related inflammation and endothelial cell apoptosis may play important roles in promoting cardiovasculardysfunction, and antioxidant tempol could achieve a partial protective effect.

Microstructure Transformation in Different Regions of Zr61.4Cu27.8Al4Ni6Y0.8 Bulk Metallic Glass Induced by Rapid Laser Welding

Haiyan Wang,Chen Yu,Wanghui Xu,Yupeng Zhang,Yanyi Ma,Yan Lin 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

An experimental study is performed on the microstructure transformation induced by rapid laser welding in the differentregions of Zr61.4Cu27.8Al4Ni6Y0.8bulk metallic glass (BMG). The laser input energy has a remarkable influence on themicrostructure and microhardness of the Zr-based BMGs. The microstructures in different regions of as-welded joints arediverse. Crystallization happens in heat-affected zone (HAZ) with crystalline dendritic phase of CuZr, which results in thedeterioration of the microhardness to 434.9 ± 17.1 HV in HAZ, much lower than that of parent material as 517 ± 5.0 HV. Meanwhile, the element profiles indicate that intragranular segregation of Cu element occurs during the crystallization process. In the center of molten zone (MZ), the structure is fully amorphous and its hardness is close to that of parent material. In the region transiting from MZ to HAZ, some nano-grains with an average size of 20–50 nm are identified. In addition,several flower-like nanostructured grains of Y2O3phase with a size ranging from 50 to 80 nm are formed in MZ’s matrix. The nanocrystallization is believed to be responsible for the enhancement of the Vickers hardness up to 560.1 ± 8.4 HV inthis region.

Resource Allocation for D2D Communication in Cellular Networks Based on Stochastic Geometry and Graph-coloring Theory

( Fangmin Xu ),( Pengkai Zou ),( Haiquan Wang ),( Haiyan Cao ),( Xin Fang ),( Zhirui Hu ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.12

In a device-to-device (D2D) underlaid cellular network, there exist two types of co-channel interference. One type is inter-layer interference caused by spectrum reuse between D2D transmitters and cellular users (CUEs). Another type is intra-layer interference caused by spectrum sharing among D2D pairs. To mitigate the inter-layer interference, we first derive the interference limited area (ILA) to protect the coverage probability of cellular users by modeling D2D users’ location as a Poisson point process, where a D2D transmitter is allowed to reuse the spectrum of the CUE only if the D2D transmitter is outside the ILA of the CUE. To coordinate the intra-layer interference, the spectrum sharing criterion of D2D pairs is derived based on the (signal-to-interference ratio) SIR requirement of D2D communication. Based on this criterion, D2D pairs are allowed to share the spectrum when one D2D pair is far from another sufficiently. Furthermore, to maximize the energy efficiency of the system, a resource allocation scheme is proposed according to weighted graph coloring theory and the proposed ILA restriction. Simulation results show that our proposed scheme provides significant performance gains over the conventional scheme and the random allocation scheme.

Stress field interference of hydraulic fractures in layered formation

Zhu, Haiyan,Zhang, Xudong,Guo, Jianchun,Xu, Yaqin,Chen, Li,Yuan, Shuhang,Wang, Yonghui,Huang, Jingya Techno-Press 2015 Geomechanics & engineering Vol.9 No.5

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

Aurantio-obtusin exerts an anti-inflammatory effect on acute kidney injury by inhibiting NF-κB pathway

Xiang Haiyan,Zhang Yun,Wu Yan,Xu Yaling,Hong Yuanhao 대한약리학회 2024 The Korean Journal of Physiology & Pharmacology Vol.28 No.1

Acute kidney injury (AKI) is one of the major complications of sepsis. Aurantio-obtusin (AO) is an anthraquinone compound with antioxidant and antiinflammatory activities. This study was developed to concentrate on the role and mechanism of AO in sepsis-induced AKI. Lipopolysaccharide (LPS)-stimulated human renal proximal tubular epithelial cells (HK-2) and BALB/c mice receiving cecal ligation and puncture (CLP) surgery were used to establish in vitro cell model and in vivo mouse model. HK-2 cell viability was measured using MTT assays. Histological alterations of mouse renal tissues were analyzed via hematoxylin and eosin staining. Renal function of mice was assessed by measuring the levels of serum creatinine (SCr) and blood urea nitrogen (BUN). The concentrations of pro-inflammatory cytokines in HK-2 cells and serum samples of mice were detected using corresponding ELISA kits. Protein levels of factors associated with nuclear factor kappa-B (NF-κB) pathway were measured in HK-2 cells and renal tissues by Western blotting. AO exerted nocytotoxic effect on HK-2 cells and AO dose-dependently rescued LPS-induced decrease in HK-2 cell viability. The concentrations of pro-inflammatory cytokines were increased in response to LPS or CLP treatment, and the alterations were reversed by AO treatment. For in vivo experiments, AO markedly ameliorated renal injury and reduced high levels of SCr and BUN in mice underwent CLP operation. In addition, AO administration inhibited the activation of NF-κB signaling pathway in vitro and in vivo. In conclusion, AO alleviates septic AKI by suppressing inflammatory responses through inhibiting the NF-κB pathway

Analytical Solution for Interaction between Tunnel Surrounding Rock and Supports in Red Sandstone Stratum

Zhen Li,Haiyan Xu,Zhijie Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

Improving the flexibility of the support system is an effective measure to prevent structural failure caused by large deformation of the surrounding rock in tunnels passing through red sandstone stratum. By utilizing the staged support installation method, the initial install location of the supports can be adjusted to control the flexibility of the support system. However, there is currently no corresponding analytical solution available to accurately predict the mechanical behavior of the surrounding rock and supports. This paper proposes an analytical solution for the whole process of interaction between the surrounding rock and supports. Firstly, based on the improved unified strength criterion and non-associated flow rule, an elastoplastic analysis of the surrounding rock of a circular tunnel in red sandstone stratum is conducted, which takes into account intermediate principal stress, dilatancy, and nonlinear strain-softening properties. Next, six types of interaction between the surrounding rock and supports are proposed, along with corresponding judge theorems. Furthermore, an analytical solution for the mechanical response of the surrounding rock and supports during the whole construction process are presented. After verifying its effectiveness, a parametric analysis is performed to investigate the influence of design parameters on the supporting effect. Finally, the application effect of the staged support installation method is compared with that of the traditional method, and the cost savings advantage of the former is demonstrated.

Nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor of three biflavonoids, isolated from roots of Stellera chamaejasme

Hui Jin,Haiyan Cui,Xiaoyan Yang,Lihong Xu,Xudong Li,Rentao Liu,Zhiqiang Yan,Xiuzhuang Li,Weili Zheng,Yuhui Zhao,Xiaoxia Song,Lihua Zhong,Anxiang Su,Bo Qin 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4

Aphelenchoides besseyi and Ditylenchus destructor can cause serious problems for a number of important agricultural crops and vegetables. In this study, the ethanol extract of Stellera chamaejasme L. roots showed strong nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor. By using a bioactivity-driven fractionation, three biflavonoids were isolated from the extract and their structures were identified by mass and nuclear magnetic resonance spectral data. Nematicidal activity bioassays revealed that isoneochamaejasmin A had the strongest nematicidal activity against A. besseyi and D. destructor with LC 50 values of 2.32 and 0.18 mM at 72 h, respectively. Chamaejasmenin B displayed weaker nematicidal activity against A. besseyi with an LC 50 value of 3.94 mM at 72 h. Neochamaejasmin B induced the lowest mortality against D. destructor with an LC 50 values of 15.6 mM at 72 h. These results suggested that the kind and position of substitutions and the relative configuration of 2-H/3-H and 2”-H/3”-H could be considered as important factors responsible for the nematicidal activity of these purified C-3/C-3″ biflavonoids.