Seismic Stability Analysis of Slope Reinforced by Frame Anchors Considering Prestress

Hao Zeng,Shuaihua Ye,Jun Zhang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

Taking the slope reinforced by frame anchors as the research object, it is assumed that the potential sliding surface of the slope is an arc. Based on the limit equilibrium theory, the seismic stability analysis model of frame anchor reinforced slope considering anchor prestress is established. This study considers prestress as uniformly distributed forces acting on the slope surface and calculates the additional stress induced by prestressing within the slope to investigate its reinforcement effect on slopes. Thus, the stability of the slope is analyzed and calculated. On this basis, the functional relationship between the center position coordinates of the potential sliding surface and the safety factor is established. Using the optimization algorithm toolbox in Matlab, the possible center position area is dynamically searched, and the minimum safety factor and its corresponding center position coordinates are obtained. Taking slope engineering as an example, the calculated results are compared with the finite element calculation results. The results show that the calculation result regarding the anchor prestress as the uniformly distributed force is reliable, and the anchor prestress can significantly enhance slope stability. This calculation method applies to slope engineering in homogeneous soil with circular sliding surfaces.

NUMERICAL SIMULATION AND PREDICTION OF NEGATIVE STORM SURGE IN THE YANGTZE RIVER ESTUARY

Zeng Hao Qin,Yi Hong Duan,De Bao Hu,Mao Xing Gong 한국해안해양공학회 1999 학술강연회 발표논문초록집 Vol.1 No.1

An attempt is made by using both statistical model and multi-layer simplified ECOM-Si model with temperature and salinity effects neglected to investigate numerically the negative storm surge (SS) in the Yangtze River estuary. An operational system for predicting the negative SS are constructed in conjunction of ECOM-Si model with the operational limited-area fine-mesh numerical weather prediction (NWP) model developed by the Shanghai Typhoon Institute(STI).To test the reliability of ECOM-Si model and to understand the computational feature of the model in simulating sea surface elevation, both semi-diurnal tide computation at the river mouth tidal station and numerical SS simulations under the action of idealized easterly and westerly winds are completed. Based on these experiments, a series of negative SS simulations induced by the cold wave, tropical and extratropical cyclones are carried out respectively, in which the objective analysis data of atmospheric forcings on the sea surface are offered by STI NWP model. Case experiments show that the predicted peak negative SS are coincident with the real ones and the phase differences between them are within a acceptable limit. The system is hopeful in operational use for predicting negative SS in the Yangtze River estuary.

Mechanical Properties and Microstructure of Basalt Fiber Reinforced Concrete Under the Single-Side Salt-Freezing–Drying–Wetting Cycles

Hao Zeng,Jin Zhang,Yang Li,Xin Su,CongZhi Gu,Kai Zhang 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.6

In the past, the salt freezing test does not often accord with the actual service environment of engineering, thus, we designed a test method of single-side salt-freezing–drying–wetting cycles. The mechanical properties and microstructure of ordinary concrete and basalt fiber reinforced concrete were studied. The mechanical property test is aimed at the splitting tensile strength and compressive strength of concrete after different cycles. The microstructure test is to study the hydration products by scanning electron microscope (SEM) and the pore structure of concrete by mercury intrusion porosimetry (MIP) test. The results indicate that the addition of basalt fiber can improve the compactness and pore structure of concrete. It is beneficial to enhance the durability of concrete under single-side salt-freezing–drying–wetting cycles. The improving effect of basalt fiber is better on the splitting tensile strength of concrete than the compressive strength. Basalt fiber exerts the best effect on reducing harmful holes in concrete. However, there is an optimal range of basalt fiber content, the performance of concrete will deteriorate with excessive fiber content. The cycles will destroy the hydration products of concrete and the synergistic effect between hydration products and fibers, but has little effect on the three-dimensional network constructed by basalt fibers. The pore structure of concrete is correlated with the mechanical properties of it under cyclic conditions, which is worth further study.

Review on Metrics and Prediction Methods of Civil Aviation Noise

Hao Feng,Yadong Zhou,Weili Zeng,Cong Ding 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.5

Civil aviation noise is one of the main factors hindering the growth of the civil aviation industry. With the increase in global air traffic demand, the problem of aviation noise pollution will become more and more serious. It is of great significance to carry out research in aviation noise. First, by summarizing the characteristics of aviation noise metrics, this paper divides them into three categories: single event noise metrics, cumulative exposure metrics, and daily metrics. Representative metrics of each category are selected for explanation and in-depth analysis. Second, according to the principles of aviation noise prediction models, this paper classifies these existing models into three categories: best practice models, scientific models, and machine learning models. Relevant academic research results are summarized. The best practice model regards the aircraft as noise point source, and its specialty is to predict noise under complex air traffic conditions. The scientific model considers the noise from the level of aircraft components and reflects the underlying physical effects. Based on data, the machine learning model uses algorithms to mine the hidden relationship between various factors and noise to achieve the purpose of noise prediction. Then, this paper introduces two kinds of aviation noise simulation software based on the best practice and scientific models, and lists their access addresses. Finally, challenges and prospects are presented from three aspects: metrics, prediction models and simulation software.

Smooth Torque Speed Characteristic of Switched Reluctance Motors

Zeng, Hui,Chen, Zhe,Chen, Hao The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

The torque ripple of switched reluctance motors (SRMs) is the main disadvantage that limits the industrial application of these motors. Although several methods for smooth-toque operation (STO) have been proposed, STO works well only within a certain torque and speed range because of the constraints of the supply voltage and peak current. Based on previous work that sought to expand the STO range, a scheme is developed in this study to determine the maximum smooth torque range at each speed. The relationship between the maximum smooth torque and speed is defined as the smooth torque speed characteristics (STSC), a concept similar to torque speed characteristics (TSC). STSC can be utilized to evaluate torque utilization by comparing it with TSC. Thus, the concept benefits the special design of SRMs, especially for the generation of smooth torque. Furthermore, the torque sharing function (TSF) derived from the proposed method can be applied to STO, which produces a higher smooth torque over a wider speed range in contrast to four typical TSFs. TSimulation and experimental results verify the proposed method.

Inferring Sequential Order of Somatic Mutations during Tumorgenesis based on Markov Chain Model

Hao Kang,Kwang-Hyun Cho,Zhang, Xiaohua Douglas,Tao Zeng,Luonan Chen IEEE 2015 IEEE/ACM transactions on computational biology and Vol.12 No.5

<P>Tumors are developed and worsen with the accumulated mutations on DNA sequences during tumorigenesis. Identifying the temporal order of gene mutations in cancer initiation and development is a challenging topic. It not only provides a new insight into the study of tumorigenesis at the level of genome sequences but also is an effective tool for early diagnosis of tumors and preventive medicine. In this paper, we develop a novel method to accurately estimate the sequential order of gene mutations during tumorigenesis from genome sequencing data based on Markov chain model as TOMC (Temporal Order based on Markov Chain), and also provide a new criterion to further infer the order of samples or patients, which can characterize the severity or stage of the disease. We applied our method to the analysis of tumors based on several high-throughput datasets. Specifically, first, we revealed that tumor suppressor genes (TSG) tend to be mutated ahead of oncogenes, which are considered as important events for key functional loss and gain during tumorigenesis. Second, the comparisons of various methods demonstrated that our approach has clear advantages over the existing methods due to the consideration on the effect of mutation dependence among genes, such as co-mutation. Third and most important, our method is able to deduce the ordinal sequence of patients or samples to quantitatively characterize their severity of tumors. Therefore, our work provides a new way to quantitatively understand the development and progression of tumorigenesis based on high throughput sequencing data.</P>

Encapsulation, Pharmacokinetics and Tissue Distribution of Interferon α-2b Liposomes after Intramuscular Injection to Rats

Hao Li,Li Yang,Gang Cheng,Hong-Yan Wei,Qun Zeng 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.6

The aim of the present study was to investigate the effect of liposome-encapsulation and liposome-size on the in vivo pharmacokinetics of interferon α-2b (IFNα-2b) following i.m. administration to rats, and whether there was any liver-targeting of these liposomes. Since liposomes of different sizes can be obtained by homogenization, the effect of homogenization on the IFNα-2b activity was also investigated. The pharmacokinetics of IFNα-2b solution (12.8 μg/kg) and IFNα-2b prepared in liposomes, including three mean sizes of 172 nm (12.2 μg/kg), 113 nm (44.2, 11.0, and 2.8 μg/kg, respectively), and 82 nm (13.1 μg/kg), were studied after a single i.m. dose to rats. Compared to a solution of IFNα-2b. administration of liposomal IFNα-2b resulted in a significantly prolonged t_max, the apparent elimination half life (t_(1/2β)) was 2.3 times longer, both AUC_(0-∞) and MRT_(0-∞) were also clearly enhanced and greater accumulation was obtained in the liver (p < 0.05). The AUC_(0-∞) increased proportionally to the administered dose of IFNα-2b liposomes. Moreover, the size of liposomes ranging from 82 nm to 172 nm had no significant difference on the pharmacokinetic behavior in vivo (p > 0.05). In sum, compared with the free form, IFNα-2b encapsulated in liposomes can alter strikingly the pharmacokinetics properties following i.m. injection and if a liposomal size ranging from 82 nm to 172 nm was used, consistent pharmacokinetic behaviors of IFNα-2b was exhibited. The liposomal formulation apparently targeted the liver, offering a potential advantage for hepatitis B treatment.

Identification and characterization of a new agar-degrading strain with the novel properties of saccharides inhibition and nitrogen fixation

Hao Wu,Guiguang Chen,Yaxi Bian,Wei Zeng,Bihong Sun,Zhiqun Liang 한국미생물학회 2017 The journal of microbiology Vol.55 No.6

In this study, a new agar-degrading strain was isolated from soil with agar as a sole carbon source and energy. Based on its morphological, physiological, biochemical characterization and 16S rDNA sequence, the strain was identified as Strep-tomyces lavendulae UN-8. The extracellular agarase activity reached 0.03 U/ml after fermentation in shake flask (250 ml), which was close to other reported non-marine micro-organisms. Furthermore, it is interesting that the growth of UN-8 would be inhibited by glucose (40 g/L) and maltose (40 g/L) with the inhibitory rate of 100% and 70%, respec-tively. Besides, UN-8 could be grown on the solid medium without any nitrogen sources, then the possible nitrogen fix-ation gene nifU was cloned from its genomic DNA. The de-duced amino acid sequence of nifU has high similarity (98%) with nitrogen fixation protein NifU from Streptomyces sp. NRRL S-104 (KJY22454.1) and Streptomyces sp. NRRL F-4428 (KJK52526.1) based on NCBI blast. It is suggested that the nifU gene of UN-8 also encoded nitrogen fixation protein NifU. These results provided some new information for the further understanding of agar-degrading strain.

Seepage characteristics of the leaching solution during in situ leaching of uranium

Zeng Sheng,Song Jiayin,Sun Bing,Wang Fulin,Ye Wenhao,Shen Yuan,Li Hao 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

Investigating the seepage characteristics of the leaching solution in the ore-bearing layer during the in situ leaching process can be useful for designing the process parameters for the uranium mining well.We prepared leaching solutions of four different viscosities and conducted experiments using a selfdeveloped multifunctional uranium ore seepage test device. The effects of different viscosities of leaching solutions on the seepage characteristics of uranium-bearing sandstones were examined using seepage mechanics, physicochemical seepage theory, and dissolution erosion mechanism. Results indicated that while the seepage characteristics of various viscosities of leaching solutions were the same in rock samples with similar internal pore architectures, there were regular differences between the saturated and the unsaturated stages. In addition, the time required for the specimen to reach saturation varied with the viscosity of the leaching solution. The higher the viscosity of the solution, the slower the seepage flow from the unsaturated stage to the saturated stage. Furthermore, during the saturation stage, the seepage pressure of a leaching solution with a high viscosity was greater than that of a leaching solution with a low viscosity. However, the permeability coefficient of the high viscosity leaching solution was less than that of a low viscosity leaching solution.

Experimental and Mechanism Investigation on Boiling Heat Transfer Characteristics of Alumina/Water Nanofluid on a Cylindrical Tube

Hao Zhang,Zeng-en Li,Shan Qing,Zhuangzhuang Jia,Jiarui Xu,Lin Ma,Sixian Wang,Aimin Zhang,Zhumei Luo 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

Nucleate pool boiling heat transfer experiments have been conducted to nanofluids on a horizontal cylinder tube under atmospheric pressure. The nanofluids are prepared by dispersing Al2O3 nanoparticles into distilled water at concentrations of 0.001, 0.01, 0.1, 1 and 2 wt.% with or without sodium, 4-dodecylbenzenesulfonate (SDBS). The experimental results showed that: nanofluids at lower concentrations (0.001 wt.% to 1 wt.%) can obviously enhance the pool boiling heat transfer performance, but signs of deterioration can be observed at higher concentration (2 wt.%). The presence of SDBS can obviously enhance the pool boiling heat transfer performance, and with the presence of SDBS, a maximum enhancement ratio of BHTC of 69.88%, and a maximum decrease ratio of super heat of 41.12% can be found in Group NS5 and NS4, respectively. The tube diameter and wall thickness of heating surface are the influential factors for boiling heat transfer coefficient. Besides, we find that Rohsenow formula failed to predict the characteristics of nanofluids. The mechanism study shows that: the decrease of surface tension, which leads to the decrease of bubble departure diameter, and the presence of agglomerates in nanofluids are the reasons for the enhanced pool boiling heat transfer performance. At higher concentration, particle deposition will lead to the decrease of distribution density of the vaporization core, and as a result of that, the boiling heat transfer performance will deteriorate.