Stability of the Rock Mass Reserved in front of Anti-slide Piles

Dapeng Zhu,Lei He,Liangkai Qin 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

To study the stability evaluation method and failure mode of reserved rock masses, the Yueyang landslide project was taken as the research object. First, based on the limit equilibrium method and elastic mechanics, the formulas for calculating the stability of a reserved rock mass were analyzed. Second, the failure modes of the reserved rock mass were tested by the experiment model. The results show that the failure modes of the reserved rock mass can be divided into three modes: upward sliding failure, downward sliding failure and tensile crack failure, which are mainly related to the strength and width of the reserved rock mass. Therefore, it is unreasonable to regard a reserved rock mass as a unified failure form in the design of anti-slide pile reinforcement. In addition, although both moderate-strength and strong-strength reserved rock masses exhibit tensile crack failure, moderate-strength rock masses under triangular loading are prone to tension-sliding failure, while strong-strength rock masses under parabolic loading are prone to tension-overturning failure. Finally, the displacement and stress monitoring results in the experiment are basically consistent with the theoretical analysis, indicating that the theoretical analysis results have high reliability.

Multiple Vehicles Collaborative Data Download Protocol via Network Coding

Wenlong Zhu,Dapeng Li,Saad, Walid IEEE 2015 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY Vol.64 No.4

<P>Data services (i.e., office on wheels and entertainment on wheels) are expected to become a primary driver in the development of future connected cars. However, the sparse spatial distribution of roadside stationary units (RSUs) along the road renders the downloading of data via roadside-to-vehicle (R2V) connections intermittent. As a result, data services, particularly for those dealing with large volumes of data, may not achieve a good quality of service. In this paper, we propose a multiple-vehicle protocol for collaborative data downloading by using network coding (NC). When multiple vehicles that are approaching each other have a common interest in certain data, they can collaboratively download the data from an RSU to significantly reduce their download time. We first derive the probability mass functions (PMFs) of the downloading completion time for three downloading methods, i.e., random, feedback, and NC based, to quantify the benefits of the proposed scheme. Our analytical derivations show that, compared with random- and feedback-based methods, the proposed approach can significantly improve the download time and will remove any need for uplink communications from vehicles to the infrastructure. Moreover, we discuss the cooperative group formation issues and vehicle-to-vehicle (V2V) data sharing in detail. Simulation results show that the proposed protocol has a more robust performance compared with random- and feedback-based schemes. In addition, we constitute simulations to show that the proposed scheme can apply to the scenarios with dynamic network topology and imperfect V2V data sharing.</P>

Local Bond Stress-Slip Model of High-Strength Stainless Steel Wire Ropes in ECC

Ke Li,Dapeng Zhao,Jiajun Fan,Juntao Zhu 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.5

Engineered cementitious composites (ECC) reinforced with high-strength stainless steel wire ropes (HSSSWR) is a new composite that has attracted much attention. Comprehensive understanding of the local bond stress-slip relationship of HSSSWR in ECC is a significant aspect to popularize the application of this new composite. In this research, the local bond stress-slip relationship between HSSSWR and ECC was investigated experimentally and theoretically, considering the influences of bond lengths, nominal diameters of HSSSWR and compressive strength of ECC. In order to accurately predict the bond stress and slip at different positions along the embedded length, a local bond stress-slip model was proposed for HSSSWR-ECC interface, and the model parameters were determined based on the pull-out test results and microsegment analysis of HSSSWR in ECC by using a nested iteration procedure. Furthermore, the three-dimension (3D) nonlinear finite element (FE) modeling method by using the proposed model was used to predict the bond-slip performance of HSSSWR in ECC. Finally, the global load-slip relationships calculated by using the iterative procedure and the 3D FE modeling method were compared with test results, which validated the acceptability of the developed local bond stress-slip model and the FE modeling method.

Prediction of Venous Trans-Stenotic Pressure Gradient Using Shape Features Derived From Magnetic Resonance Venography in Idiopathic Intracranial Hypertension Patients

Ma Chao,Zhu Haoyu,Liang Shikai,Chang Yuzhou,Mo Dapeng,Jiang Chuhan,Zhang Yupeng 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.1

Objective: Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology associated with venous sinus stenosis. This study aimed to develop a magnetic resonance venography (MRV)-based radiomics model for predicting a high trans-stenotic pressure gradient (TPG) in IIH patients diagnosed with venous sinus stenosis. Materials and Methods: This retrospective study included 105 IIH patients (median age [interquartile range], 35 years [27– 42 years]; female:male, 82:23) who underwent MRV and catheter venography complemented by venous manometry. Contrast enhanced-MRV was conducted under 1.5 Tesla system, and the images were reconstructed using a standard algorithm. Shape features were derived from MRV images via the PyRadiomics package and selected by utilizing the least absolute shrinkage and selection operator (LASSO) method. A radiomics score for predicting high TPG (≥ 8 mmHg) in IIH patients was formulated using multivariable logistic regression; its discrimination performance was assessed using the area under the receiver operating characteristic curve (AUROC). A nomogram was constructed by incorporating the radiomics scores and clinical features. Results: Data from 105 patients were randomly divided into two distinct datasets for model training (n = 73; 50 and 23 with and without high TPG, respectively) and testing (n = 32; 22 and 10 with and without high TPG, respectively). Three informative shape features were identified in the training datasets: least axis length, sphericity, and maximum three-dimensional diameter. The radiomics score for predicting high TPG in IIH patients demonstrated an AUROC of 0.906 (95% confidence interval, 0.836– 0.976) in the training dataset and 0.877 (95% confidence interval, 0.755–0.999) in the test dataset. The nomogram showed good calibration. Conclusion: Our study presents the feasibility of a novel model for predicting high TPG in IIH patients using radiomics analysis of noninvasive MRV-based shape features. This information may aid clinicians in identifying patients who may benefit from stenting.

Theoretical Prediction Model for Surface Settlement Caused by the Excavation of New Tunnels Undercrossing Existing Tunnels Based on Modified Stochastic Medium Theory

Qiang Xu,Shengxiang Lei,Yongquan Zhu,Wei Zhao,Cong Wang,Dapeng Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

The deformation pattern of the stratum caused by constructing a new metro tunnel crossing an existing tunnel is different from the deformation pattern caused by general tunnel construction. However, the prediction results by the ordinary surface settlement prediction model often bring significant errors because the complex influence of existing tunnels on the surface settlement caused by the excavation of new tunnels is always neglected. Based on the equivalent layered method and stochastic medium theory, a prediction model for the surface settlement due to excavating a new tunnel under an existing tunnel in the heterogeneous stratum was established. By equating the bending stiffness of an existing tunnel before and after applying the equivalent layered method, the layer index was determined. The critical parameters of the stochastic medium theory were derived based on the relationship between the critical parameters of both the Peck empirical formula and the stochastic medium theory. The surface settlement of some typical projects was predicted and compared by the prediction model in this paper and the ordinary prediction model. The comparison shows that the proposed prediction model and parameter determination method in this paper had high accuracy and applicability. The results of the prediction model in this paper fit the results of numerical calculation. The research of this paper can provide a new method for the theoretical prediction of surface settlement caused by the excavation of a new tunnel under an existing tunnel in the heterogeneous stratum and the determination of critical parameters of the stochastic medium theory.problem in the construction industry, and helps reducing the material waste and budget cost.

Raman scattering investigations on Co-doped ZnO epitaxial films: Local vibration modes and defect associated ferromagnetism

Qiang Cao,Shumin He,Yuanyuan Deng,Dapeng Zhu,Xiaodong Cui,Guolei Liu,Huai-Jin Zhang,Shishen Yan,Yanxue Chen,Liangmo Mei 한국물리학회 2014 Current Applied Physics Vol.14 No.5

Raman scattering spectroscopy has been performed on high quality Co-doped ZnO epitaxial films, which were grown on Al2O3 (0001) by oxygen-plasma assisted molecular beam epitaxy. Raman measurements revealed two local vibration modes (LVMs) at 723 and 699 cm1 due to the substitution of Co2þ in wurtzite ZnO lattice. The LVM at 723 cm1 is found to be an elemental sensitive vibration mode for Co substitution. The LVM at 699 cm1 can be attributed to enrichment of Co2þ bound with oxygen vacancy, the cobalteoxygen vacancyecobalt complexes, in Zn1xCoxO films associated with ferromagnetism. The intensity of LVM at 699 cm1, as well as saturated magnetization, enhanced after the vacuum annealing and depressed after oxygen annealing.

Mining and Verification of Cold Stress-responsive Genes Correlated with the Cryogenic Autolysis of Volvariella volvacea

Ming Gong,Hong Wang,Mingjie Chen,Dapeng Bao,Qiuming Zhu,Qi Tan 한국버섯학회 2017 버섯 Vol.21 No.2

In Volvariella volvacea, a species of edible mushroom, cryogenic autolysis is a typical part of abnormal metabolism. Previous functional annotation cluster analyses of cold-induced gene expression profiles have shown that the ubiquitin-conjugating enzyme E2 (UBE2) and the cyclin-like F-box domain (FBDC) form the functional clusters. Among them, a specific FBDC gene has been found to be in response to cold stress and correlated with the cryogenic autolysis of V. volvacea. In this study, analysis of gene expression profiling showed that only one type of UBE2 in V. volvacea (UBEV2) was significantly up-regulated. Further quantitative real-time PCR analysis confirmed that the expression of UBEV2 was significantly up-regulated (P < 0.05) after cold-treatment lasting 4, 6, and 8 h. Western-bolt analyses confirmed that the protein expression of UBEV2 was in response to cold stress. This provided evidence that UBEV2 was a cold stress-responsive gene and closely correlated with cryogenic autolysis. The specific distribution of UBEV2 in recently diverged herb decay fungi indicated that UBEV2 was not evolutionarily correlated with early diverging fungi. Phylogenetic analysis indicated that UBEV2 was generated by horizontal gene transfer (HGT) from the ancestry of Selaginella moellendorffii UBE2. Further relative time estimation and detection of natural selection showed that there has been recent positive selection after HGT in UBEV2. Molecular modeling and logo analysis showed that the cysteine-cysteine motif is the characteristic of the UBEV2 family. These observations indicate that UBEV2 and FBDV1 are the newly discovered cold stress-responsive genes correlated with the cryogenic autolysis of V. volvacea.