Dynamic Unloading Instability Mechanism of Underground Cavern Based on Seepage-Damage Coupling

Li-Ping Li,Wenfeng Tu,Zongqing Zhou,Shao-shuai Shi,Mingguang Zhang,Yuxue Chen 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.5

The seepage-damage coupling effect will aggravate the instability of the surrounding rock during the unloading process of underground cavern excavation. Considering this coupling effect and excavation disturbance, the theoretical solution of the stress state of surrounding rock is derived by using the elastic-brittle damage model. The dynamic criterion of the instability and water inrush is presented. Based on the theoretical derivation, the calculation program for the seepage-damage analysis of the surrounding rock under dynamic unloading is programmed, and the seepage flow and the radius of the damage zone of the surrounding rock are calculated. By analysing the variation of radius of the damaged zone with pore water pressure and excavation radius under different calculation conditions, the influence of dynamic unloading disturbance on the damaged zone of the surrounding rock is discussed. The radius of the damaged zone increases with the pore water pressure and excavation radius. Considering the effect of dynamic unloading, the calculation result of the damaged zone radius and seepage discharge of underground cavern are much larger than the theoretical calculation and coupling calculation of seepage-damage without dynamic unloading. Research methods and results can provide guidance and reference for similar engineering research.

Magneto-rheological variable damping and variable stiffness torsional vibration control of powertrain transmission

Wenfeng Li,Xinfeng Ge,Manying Liang,Xiong Deng 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

Torsional vibration is prevalent in rotating mechanical systems such as powertrain transmission. It is a hot spot in current torsional vibration control research to effectively suppress torsional vibration of the system by implementing adaptive torsional dampers with adjustable parameters. The current research focuses on the variable damping torsional vibration absorber, while the investigation on variable stiffness torsional vibration absorber remains at the theoretical stage. With this premise, a transmission system with a novel magnetorheological variable stiffness and damping torsional vibration absorber (MR-VSDTVB) is proposed. MR-VSDTVB with sequential adjustment of torsional damping and stiffness parameters is developed. Its aggregate dynamic output characteristics of stiffness and damping are tested. To describe the nonlinear output characteristics with coupled multiple control parameters of MR-VSDTVB and the subsequent control, a GA-BP neural network model and a hierarchical inverse model are adopted. To validate the feasibility of the transmission system with MRVSDTVB, a dynamic model of the transmission system with MR-VSDTVB is constructed and simplified, and then the numerical simulation analysis and experimental tests are carried out. The output performances of the MR semi-active system with various traditional semi-active control strategies show that the transmission system with the proposed MR-VSDTVB can suppress torsional vibration effectively.

Zero-watermarking Algorithm for Medical Volume Data Based on Legendre Chaotic Neural Network and Perceptual Hashing

Baoru Han,Lisha Cai,Wenfeng Li 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.1

Medical information digitization makes the medical information storage and extraction more convenient. Medical image information security and copyright protection is also gradually being taken seriously, and some medical image watermarking has been applied. According to the characteristics of three-dimensional medical images, this paper proposes a robust zero-watermarking algorithm for medical volume data based on legendre chaotic neural network and perceptual hashing. The algorithm is based on three-dimensional discrete wavelet transform frequency analysis features, which uses perceptual hashing technique to extract medical volume data itself feature vector in order to structure robust zero watermarking. And using legendre chaotic neural network to generate chaotic sequence to enhance the security of the watermarking. The algorithm achieves a combination of legendre chaotic neural network encryption and zero-watermarking technology, which can improve the medical volume data watermarking algorithm security and robustness. The simulation results show the effectiveness of the algorithm.

High brightness and precise adjustment of multicolor-tunable luminescence of Lu2GeO5:Tb3+, Eu3+ phosphors for white LEDs

Shaoan Zhang,Yuanxing Li,Wenfeng Li,Zhenzhang Li,Minfan Qiu,Zhongfei Mu,Yang Li,Yihua Hu 한국물리학회 2019 Current Applied Physics Vol.19 No.9

High brightness and precise adjustment of luminescence colour of phosphors are two main targets in the research of phosphor-converted white LEDs. However, few feasible strategy can be employed to achieve the multicolortunable luminescence under the premise of maintaining high quantum efficiency. Here, we demonstrate a highefficiency energy-transfer process from Tb3+ to Eu3+ ions with a higher luminescent quantum efficiency (64.5% and 53.4%, respectively), and green-red multicolor emission in Lu2GeO5 host via varying the doping content of Tb3+ and Eu3+ ions. Besides, Lu2GeO5:Tb3+, Lu2GeO5: Eu3+ and Lu2GeO5: Tb3+, Eu3+ all exhibit weak thermal quenching which ensures the stable use of white LED device in the high temperature environment. This paper provides a novel multicolor-tunable phosphor with high brightness, efficient energy transfer and weak thermal quenching, which presents a potential application for UV-converted white LEDs.

Bacterial Community Structure and Function Shift in Rhizosphere Soil of Tobacco Plants Infected by Meloidogyne incognita

Wenjie Tong(Wenjie Tong),Junying Li(Junying Li),Wenfeng Cong(Wenfeng Cong),Cuiping Zhang(Cuiping Zhang),Zhaoli Xu(Zhaoli Xu),Xiaolong Chen(Xiaolong Chen),Min Yang(Min Yang),Jiani Liu(Jiani Liu),Lei Yu 한국식물병리학회 2022 Plant Pathology Journal Vol.38 No.6

Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

A STUDY ON (k, 𝜇)'-ALMOST KENMOTSU MANIFOLDS

Li, Jin,Liu, Ximin,Ning, Wenfeng The Honam Mathematical Society 2018 호남수학학술지 Vol.40 No.2

Let ${\mathcal{C}}$, ${\mathcal{M}}$, ${\mathcal{L}}$ be concircular curvature tensor, M-projective curvature tensor and conharmonic curvature tensor, respectively. We obtain that if a non-Kenmotsu ($k,{\mu}$)'-almost Kenmotsu manifold satisfies ${\mathcal{C}}{\cdot}{\mathcal{S}}=0$, ${\mathcal{R}}{\cdot}{\mathcal{M}}=0$ or ${\mathcal{R}}{\cdot}{\mathcal{L}}=0$, then it is locally isometric to the Riemannian product ${\mathds{H}}^{n+1}(-4){\times}{\mathds{R}}^n$.

Soil Humic Aicd Complexation with Protein

Wenfeng Tan,Yan Li,Luuk K. Koopal,Willem Norde 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Effect Factor Analysis of Spraying Quality for Agricultural Chemicals

Wenfeng Sun,Qichao Li,Yongcun Fan,Yanhua Wan,Teng Wang,Baozhong Cong 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.11

As one of the most important parts of the agricultural work, agricultural chemicals spray is to protect the plants from weeds, pest and bacteria. With development of high efficient agricultural chemicals, the consumption of agricultural chemicals should be controlled within a couple of liter per hectare in theory. But it’s very hard to realize effective use of agricultural chemicals in fact. In this paper, the most effect factors of spray quality such as droplets size, environment temperature, droplets density, nozzle type and spray method were analyzed in agricultural chemicals spray operation. Droplet size effects drift and uniformity of droplet distribution directly. Environment temperature effects drift and uniformity of droplet distribution greatly. Character of nozzle affects spraying quality directly. All research of the paper can offer valuable reference to appropriate application of agricultural chemicals.

Substrate Temperature Dependence of the Properties of Single-layer MoS$_2$ Film deposited by Using Pulsed Laser Deposition

Wenfeng Xiang,Dong Li,Minghao Hu,Wenzheng Yue,Haizhong Guo 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.5

Single-layer MoS$_2$ films were deposited on sapphire substrates by using pulsed laser deposition. The substrate temperature dependence of the structural, optical and photoluminescence properties of single-layer MoS$_2$ films was investigated. An increased substrate temperature improved the surface morphology and the crystal quality of the MoS$_2$ films. Moreover, the absorption and the photoluminescence properties of the MoS$_2$ films were enhanced. In addition, the mechanism underlying the effect of substrate temperature on the properties of single-layer MoS$_2$ films is discussed.

Transmission of symbiotic fungus with a nonsocial leaf-rolling weevil

Xiaoqiong Li,Wenfeng Guo,Yuanguang Wen,Manoj Kumar Solanki,Jianqing Ding 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.3

Transmission modes of symbionts with fungus-growing insects are closely related to the stability of symbioses. As compare to social fungus-farming insects, transmission modes of nonsocial fungus-farming insects need to be further investigated. Euops chinensis, a nonsocial leaf-rolling weevil, harbors a symbiotic fungus Penicillium herquei in the specialized mycangium. Previous works have indicated that P. herquei is cultivated to host plants by females during oviposition process, however, it is still unclear when (before or after oviposition) and how P. herquei is transmitted. In this study, we observed fungal cultivating behaviors and adult bodies by scanning electron microscopy (SEM), and compared isolation rates of P. herquei on ovary eggs, newly oviposited eggs, cradle leaves (leaf pieces cut before rolling cradles), cradles, and female mycangia. Fungal isolateswere identified by internal transcribed spacers (ITS) and cytochrome oxidase I (COI) genes.Wefound the female's serrated tarsi and comb-like setae on the abdomen were specialized structures for fungal transmission. Newly oviposited eggs showed 81.11% frequency of fungal symbionts, but ovary eggs did not showany growth of fungal symbionts. Isolation rates of P. herquei on cradle leaves, mycangia and cradles were 76.67%, 77.71% and 87.72%, respectively. Analyses of ITS and COI genes showed that isolated fungal strains belong to the same species. We concluded that P. herquei was transmitted before oviposition, and the female's tarsi are newly found specialized structures for fungal transmission. This study elucidates the cultivar transmission modewith fungus-farming attelabidweevils, and might be useful to study of other fungiculture mutualisms.