Mechanical Properties and Damming Behaviors of Gravelly Solidified Soil for Earth-Rock Dam Core Wall

Donghai Liu,Huaijian Dai,Zhao Zhang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.6

To decrease the arch effect of core wall effectively has become an important requirement forhigh earth-rock dams. To address this issue, a soil solidifier was used to improve the properties of gravelly soil. This study investigated the durability and mechanical performances of gravelly soils mixed with different proportions of solidifier through the permeability, freeze-thaw, and triaxial compression tests. Furthermore, the microstructure of gravelly solidified soil was explored, and the mechanism for the performance improvement was explained. Finally, the influence of mixing the solidifier on dam stress, deformation and the decrease of arch effect was analyzed using the finite element method. The results indicate that a large number of long needle-like hydrates and crystalline interlocking structures are present in the gravelly solidified soil. Therefore, the impermeability, frost resistance, toughness and shear strength of the gravelly solidified soil are significantly higher than those of the normal gravelly soil. In addition, the settlement and the arch effect are decreased dramatically with mixing the solidifier. Thus, this study provides an alternative to high core wall materials and a new approach to improve the arch effect of 300-meter-height level core wall earth-rock dams.

Stabilization of Li Metal Anode in DMSO-Based Electrolytes via Optimization of Salt-Solvent Coordination for Li-O₂ Batteries

Liu, Bin,Xu, Wu,Yan, Pengfei,Kim, Sun Tai,Engelhard, Mark H.,Sun, Xiuliang,Mei, Donghai,Cho, Jaephil,Wang, Chong-Min,Zhang, Ji-Guang Wiley (John WileySons) 2017 ADVANCED ENERGY MATERIALS Vol.7 No.14

Calculation of PI Controller Stable Region Based on D-Partition Method

Liu Jinggong,Xue Yali,Li Donghai 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

Based on D-partition method, a fast calculation approach for PI controller stable region is introduced. The boundary of the PI stable region is calculated first using D-partition method, and then several sets of equations and inequalities are introduced sequentially to judge which side of the boundary is stable. The approach is simple, and can be applied to any self-stable systems with or without time-delays, while only the process frequency responses are needed. To illustrate its feasibility, some examples are given.

Relationship between Porosity and the Modified Constitutive Model Parameters of Asphalt Concrete Core Material

Zhoumei Chang,Donghai Liu,Jianyu Liang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

Porosity is a key control index for ensuring the compaction quality of rockfill dams with asphalt concrete cores. The porosity of the asphalt mixture is an important factor for an asphalt concrete core dam to obtain adequate strength and control the core deformation. However, the compaction quality (i.e., porosity) of the asphalt core wall inevitably exhibits spatial differences during actual construction process. To analyze the quantitative relationship between the porosity of the asphalt concrete core and the Duncan-Chang model parameters, triaxial tests under different confining pressures were carried out with asphalt concrete samples of different porosities. Based on the test results, the applicability of the Duncan-Chang model was assessed. Aiming at the limitation of the Duncan-Chang model, which is unable to characterize the strain softening and shear dilatancy of materials, a modified constitutive model of the asphalt concrete core was proposed. The determination method of the proposedmodel parameters was provided and verified by triaxial test results. A regression relationship was established between the porosity of the core material and the parameters of the modified constitutive model. This study provides a prerequisite for conducting refined finite element analysis on the mechanical performance of the asphalt core rockfill dams, taking into account the spatial differences in compaction quality of the asphalt concrete core.

Shellix : An Efficient Approach for Shellcode Detection

Mo Chen,Changzhen Hu,Donghai Tian,Xin Wang,Yuan Liu,Ning Li 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

Code injection attacks are widely used by attackers to compromise computer systems. Attackers could obtain the control of a victim's computer system by injecting shellcode to the vulnerable program. The existing solutions to detect shellcode can be grouped into two categories: static analysis and dynamic analysis. Static analysis can detect shellcode efficiently, but cannot handle the shellcode that employs obfuscation techniques. Dynamic analysis is able to detect the obfuscated shellcode, however it is still limited to detect the recent virtualization-aware shellcode. In this paper, we present a novel shellcode detection approach without using any virtualization technology. We implement our approach based on the commodity OS kernel which is compatible to the existing system. Our approach is able to detect the shellcode that could be aware of the virtualization environment and reduces the probability of exposing detection environment. Our experimental evaluations show that our system can effectively detect a large set of shellcode instances with good performance.

Numerical Study of the Role of Microphysical Latent Heating and Surface Heat Fluxes in a Severe Precipitation Event in the Warm Sector over Southern China

Jin-Fang Yin,Donghai Wang,Zhao-Ming Liang,Chong-Jian Liu,Guo-Qing Zhai,Hong Wang 한국기상학회 2018 Asia-Pacific Journal of Atmospheric Sciences Vol.54 No.1

Simulations of the severe precipitation event that occurred in the warm sector over southern China on 08 May 2014 are conducted using the Advanced Weather Research and Forecasting (WRF-ARWv3.5.1) model to investigate the roles of microphysical latent heating and surface heat fluxes during the severe precipitation processes. At first, observations from surface rain gauges and groundbased weather radars are used to evaluate the model outputs. Results show that the spatial distribution of 24-h accumulated precipitation is well reproduced, and the temporal and spatial distributions of the simulated radar reflectivity agree well with the observations. Then, several sensitive simulations are performed with the identical model configurations, except for different options in microphysical latent heating and surface heat fluxes. From the results, one of the significant findings is that the latent heating from warm rain microphysical processes heats the atmosphere in the initial phase of the precipitation and thus convective systems start by self-triggering and selforganizing, despite the fact that the environmental conditions are not favorable to the occurrence of precipitation event at the initial phase. In the case of the severe precipitation event over the warm sector, both warm and ice microphysical processes are active with the ice microphysics processes activated almost two hours later. According to the sensitive results, there is a very weak precipitation without heavy rainfall belt when microphysical latent heating is turned off. In terms of this precipitation event, the warm microphysics processes play significant roles on precipitation intensity, while the ice microphysics processes have effects on the spatial distribution of precipitation. Both surface sensible and latent heating have effects on the precipitation intensity and spatial distribution. By comparison, the surface sensible heating has a strong influence on the spatial distribution of precipitation, and the surface latent heating has only a slight impact on the precipitation intensity. The results indicate that microphysical latent heating might be an important factor for severe precipitation forecast in the warm sector over southern China. Surface sensible heating can have considerable influence on the precipitation spatial distribution and should not be neglected in the case of weak large-scale conditions with abundant water vapor in the warm sector.

The Design of A Reference Model-Based Proportional-Integral-Derivative Controller with the Generalized Derivative

Gengjin Shi,Chengbo Dai,Shaojie Liu,Donghai Li,Yanjun Ding 제어로봇시스템학회 2023 제어로봇시스템학회 국제학술대회 논문집 Vol.2023 No.10

Predictors of Difficult Laryngeal Exposure in Suspension Laryngoscopy: A Systematic Review and Meta-Analysis

Mengshu Wang,Guo Li,Yong Liu,Yuanzheng Qiu,Huihong Chen,Wang Liwen,Donghai Huang,Xin Zhang 대한이비인후과학회 2024 Clinical and Experimental Otorhinolaryngology Vol.17 No.2

Objectives. Considerable research has been focused on independent predictors of difficult laryngeal exposure (DLE) duringsuspension laryngoscopy. However, previous studies have yielded inconsistent results and conclusions. Consequently,we performed a meta-analysis of the existing literature with the aim of identifying significant parameters for a stan-dardized preoperative DLE prediction system. Methods. We systematically retrieved articles from the PubMed, Embase, Web of Science, China National Knowledge Infra-structure, and Wanfang databases up to October 2022. Data from eligible studies were extracted and analyzed usingthe R programming language. The effect measures included odds ratios (ORs) with 95% confidence intervals (CIs) fordichotomous variables and mean differences (MDs) with 95% CIs for continuous variables. Results. The search yielded 1,574 studies, of which 18 (involving a total of 2,263 patients) were included. Pooled analysisdemonstrated that patients with DLE during microsurgery tended to be male (OR, 1.73; 95% CI, 1.16–2.57); wereolder (MD, 5.47 years, 95% CI, 2.44–8.51 years); had a higher body mass index (BMI; MD, 1.19 kg/m2; 95% CI,0.33–2.05 kg/m2); had a greater neck circumference (MD, 2.50 cm; 95% CI, 1.56–3.44 cm); exhibited limited mouthopening (MD, −0.52 cm; 95% CI, −0.88 to −0.15 cm); had limited neck flexibility (MD, −10.05 cm; 95% CI, −14.10to −6.00 cm); displayed various other anatomical characteristics; and had a high modified Mallampati index (MMI)or test score (OR, 3.37; 95% CI, 2.07–5.48). Conclusion. We conducted a comprehensive and systematic analysis of the factors relevant to DLE. Ultimately, we identi-fied sex, age, BMI, neck circumference, MMI, inter-incisor gap, hyomental distance, thyromental distance, sternomen-tal distance, and flexion-extension angle as factors highly correlated with DLE.

Pycnogenol attenuates atherosclerosis by regulating lipid metabolism through the TLR4–NF-κB pathway

Hong Luo,Jing Wang,Chenhui Qiao,Ning Ma,Donghai Liu,Weihua Zhang 생화학분자생물학회 2015 Experimental and molecular medicine Vol.47 No.-

Atherosclerosis is a leading cause of death worldwide and is characterized by lipid-laden foam cell formation. Recently,pycnogenol (PYC) has drawn much attention because of its prominent effect on cardiovascular disease (CVD). However, its protective effect against atherosclerosis and the underlying mechanism remains undefined. Here PYC treatment reduced areas of plaque and lipid deposition in atherosclerotic mice, concomitant with decreases in total cholesterol and triglyceride levels and increases in HDL cholesterol levels, indicating a potential antiatherosclerotic effect of PYC through the regulation of lipid levels. Additionally, PYC preconditioning markedly decreased foam cell formation and lipid accumulation in lipopolysaccharide (LPS)-stimulated human THP-1 monocytes. A mechanistic analysis indicated that PYC decreased the lipid-related protein expression of adipose differentiation-related protein (ADRP) and adipocyte lipid-binding protein (ALBP/aP2) in a dose-dependent manner. Further analysis confirmed that PYC attenuated LPS-induced lipid droplet formation via ADRP and ALBP expression through the Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) pathway, because pretreatment with anti-TLR4 antibody or a specific inhibitor of NF-κB (PDTC) strikingly mitigated the LPS-induced increase in ADRP and ALBP. Together, our results provide insight into the ability of PYC to attenuate bacterial infection-triggered pathological processes associated with atherosclerosis. Thus PYC may be a potential lead compound for the future development of antiatherosclerotic CVD therapy.