Development of a Novel 3-DOF Suspension Mechanism for Multi-Function Stylus Profiling Systems

Jia Tian,Yanling Tian,Zhiyong Guo,Fujun Wang,Dawei Zhang,Xianping Liu,Bijian Shirinzadeh 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.11

This paper proposes a novel 3-DOF suspension mechanism for multi-function stylus profiling systems. Incorporating an electromagnetic force actuator, the 3-DOF suspension mechanism provides a controlled loading force. For reasons of the thermal and mechanical stability, a triangular flexure structure is utilized to support the stylus. The stiffness matrix method is used to establish the analytical stiffness model of the 3-DOF suspension mechanism. Considering the 3-DOF suspension mechanism as a 3-DOF lumped-mass-spring system, the dynamic model is established. Finite element analysis (FEA) is used to validate the established static and dynamic models of the 3-DOF suspension mechanism. A prototype is fabricated and experimental tests are carried out to characterize the mechanism’s performance. The results show that the 3-DOF suspension mechanism provides a controlled force in a range of up to 10 mN and has a working range in excess of 10 μm with a first natural frequency of 342 Hz in Z axis, indicating good capability for multi-function measurements at the micro/nano scale.

Improved Stability and Stabilization Results for Stochastic Synchronization of Continuous-Time Semi-Markovian Jump Neural Networks With Time-Varying Delay

Wei, Yanling,Park, Ju H.,Karimi, Hamid Reza,Tian, Yu-Chu,Jung, Hoyoul IEEE 2018 IEEE transactions on neural networks and learning Vol.29 No.6

<P>Continuous-time semi-Markovian jump neural networks (semi-MJNNs) are those MJNNs whose transition rates are not constant but depend on the random sojourn time. Addressing stochastic synchronization of semi-MJNNs with time-varying delay, an improved stochastic stability criterion is derived in this paper to guarantee stochastic synchronization of the response systems with the drive systems. This is achieved through constructing a semi-Markovian Lyapunov–Krasovskii functional together as well as making use of a novel integral inequality and the characteristics of cumulative distribution functions. Then, with a linearization procedure, controller synthesis is carried out for stochastic synchronization of the drive-response systems. The desired state-feedback controller gains can be determined by solving a linear matrix inequality-based optimization problem. Simulation studies are carried out to demonstrate the effectiveness and less conservatism of the presented approach.</P>

A Review on Bioactive Compounds from Marine-Derived Chaetomium Species

( Yuan Tian ),( Yanling Li ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.5

Filamentous marine fungi have proven to be a plentiful source of new natural products. Chaetomium, a widely distributed fungal genus in the marine environment, has gained much interest within the scientific community. In the last 20 years, many potential secondary metabolites have been detected from marine-derived Chaetomium. In this review, we attempt to provide a comprehensive summary of the natural products produced by marine-derived Chaetomium species. A total of 122 secondary metabolites that were described from 2001 to 2021 are covered. The structural diversity of the compounds, along with details of the sources and relevant biological properties are also provided, while the relationships between structures and their bioactivities are discussed. It is our expectation that this review will be of benefit to drug development and innovation.

Torsional Properties of Boron Nitride Nanocones with Different Cone Heights, Disclination Angles and Simulation Temperatures

Yuan Li,Yanling Tian,Chengjuan Yang,Kunhai Cai,Dawei Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.7

The torsional properties of single-walled boron nitride (BN) nanocones at different cone heights, disclination angles and simulation temperatures have been investigated using molecular dynamics (MD) simulation. The simulation results indicate that the torque and average potential energy decrease with the increasing cone height and disclination angle, and the failure torsion angle increases with the increasing cone height and disclination angle. For different simulation temperatures, the torsional behavior of BN nanocones at higher simulation temperature is more serious and earlier to reach a failure point, the maximum torque and average potential energy of the system decrease with the increasing simulation temperature. For different loading rates, the failure torsion angle decreases with the increasing loading rate, so the fracture of BN nanocone occurred earlier with higher loading rate. Therefore, the cone height, disclination angle, simulation temperature and loading rate are considered to be four main influencing factors for the torsional properties of the BN nanocones.

Rapid Predictions for Lower-Order Dynamics of Machine Tools Based on the Rigid Multipoint Constraints

Yiwei Ma,Yanling Tian,Xianping Liu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.3

This study presents a rapid predicting method for lower-order dynamic performances of machine tools. Firstly, the governing equation of motion of the component substructure is obtained drawing on the dynamic condensation from the finite element analysis. Secondly, employing the rigid multipoint constraints at the joint and interface level, the improved reduced dynamic model of component substructures is formulated, resulting in a minimum set of generalized coordinates for external nodes. Then, utilizing the screw theory, the local stiffness mapping between joint and interfaces is illustrated. This is followed by merging the component and joint substructures, resulting in the reduced dynamic model of the entire machine tool. The proposed model is hugely efficient for predicting the distributions of dynamic performances within the entire workspace and guiding the optimal functional design under the framework of virtual machine tools. Finally, a comparison study on a box-in-box type precision horizontal machine tool shows that the lower-order dynamics predicted within the proposed approach have the same trend as those obtained by a complete order finite element model. The experimental modal analysis test shows that the errors of natural frequencies between the proposed model and experiments are lower than 15.61%, demonstrating the effectiveness and accuracy of the proposed model.

Screening of Endophytic Antagonistic Bacterium from Phellodendron amurense and Their Biocontrol Effects against Canker Rot

Shu-Jiang Li,Xinmei Fang,Hanlian Zhang,Yanling Zeng,Tian-Hui Zhu 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.3

Thirty-four strains of bacteria were isolated from Phellodendron amurense. Using Nectria haematococca as an indicator strain, the best strain, B18, was obtained by the growth rate method. The morphological, physiological and biochemical characteristics of strain B18 and its 16S DNA gene sequence were identified, and the biocontrol effect of strain B18 was assessed in pot and field tests, as well as in a field-control test. Drilling methods were used to determine the antibacterial activity of metabolites from strain B18 and their effects on the growth of pathogen mycelia and spores. The best bacteriostatic rate was 85.4%. B18 can hydrolyse starch and oxidize glucose but does not produce gas; a positive result was obtained in a gelatine liquefaction test. According to 16S DNA gene sequencing, strain B18 is Bacillus methylotrophicus (GenBank accession number: MG457759). The results of pot and field-control trials showed 98% disease control when inoculating 108 cfu/ ml of the strain. The disease control effect of the B18 culture liquid (concentrations of 108, 2 × 106, 106, 5 × 105 and 2.5 × 105 cfu/ml) in the field-control test was higher than 80%, and the cure rate of the original delivery solution was 96%. Therefore, in the practical forestry production, a 2.5 × 105 cfu/ml culture liquidshould be applied in advance to achieve good control effects.

Green Fabrication of Anti-friction Slippery Liquid-Infused Metallic Surface with Sub-millimeter-Scale Asymmetric Bump Arrays and Its Application

Zhongxu Lian,Yi Cheng,Jinkai Xu,Jinlong Xu,Wanfei Ren,Yanling Tian,Huadong Yu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.5

In this work, we present a simple technique for green fabrication of slippery liquid-infused surface (SLIS) with anti-friction property on various metallic substrates using wire electrical discharge machining. Micro-crater structures were successfully obtained, and the surface had excellent liquid-repellent property after modification and infusion of silicone oil. A wide range of liquids including water, juice, coffee, tea, vinegar, albumin, glycerol, and ketchup could easily slid down the surface tilted at an angle of 10° without leaving any trace. The influences of the number of cutting step on the morphology and wettability of the surface were studied comprehensively. Further, the tribological properties of the surface were analyzed and the results showed that the SLIS had a decrease of 73.2% in friction coefficient as compared to that of the smooth surface. By studying the morphology of the worn surfaces, it is found that the SLIS had slight abrasive wear behavior. To demonstrate the precision processing ability of this technology, we fabricated slippery sub-millimeter-scale asymmetric bump arrays, and the experiment results showed that the asymmetric bump arrays had excellent water harvesting ability at low temperatures. This kind of environment-friendly precision machining technology will promote the practical applications of metallic functional materials.

Activation of TLR7-mediated autophagy increases epileptic susceptibility via reduced KIF5A-dependent GABAA receptor transport in a murine model

Liu Jing,Ke Pingyang,Guo Haokun,Gu Juan,Liu Yanling,Tian Xin,Wang Xuefeng,Xiao Fei 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

The pathophysiological mechanisms underlying epileptogenesis are poorly understood but are considered to actively involve an imbalance between excitatory and inhibitory synaptic transmission. Excessive activation of autophagy, a cellular pathway that leads to the removal of proteins, is known to aggravate the disease. Toll-like receptor (TLR) 7 is an innate immune receptor that regulates autophagy in infectious and noninfectious diseases. However, the relationship between TLR7, autophagy, and synaptic transmission during epileptogenesis remains unclear. We found that TLR7 was activated in neurons in the early stage of epileptogenesis. TLR7 knockout significantly suppressed seizure susceptibility and neuronal excitability. Furthermore, activation of TLR7 induced autophagy and decreased the expression of kinesin family member 5 A (KIF5A), which influenced interactions with γ-aminobutyric acid type A receptor (GABAAR)-associated protein and GABAARβ2/3, thus producing abnormal GABAAR-mediated postsynaptic transmission. Our results indicated that TLR7 is an important factor in regulating epileptogenesis, suggesting a possible therapeutic target for epilepsy.

Antimicrobial and Cytotoxic Activity of Endophytic Fungi from Lagopsis supina

Zhang Dekui,Sun Weijian,Xu Wenjie,Ji Changbo,Zhou Yang,Sun Jingyi,Tian Yutong,Li Yanling,Zhao Fengchun,Tian Yuan 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.4

In this study, five endophytic fungi belonging to the Aspergillus and Alternaria genera were isolated from Lagopsis supina. The antimicrobial activity of all fungal fermented extracts against Staphylococcus and Fusarium graminearum was tested using the cup-plate method. Among them, Aspergillus ochraceus XZC-1 showed the best activity and was subsequently selected for large-scale fermentation and bioactivity-directed separation of the secondary metabolites. Four compounds, including 2- methoxy-6-methyl-1,4-benzoquinone (1), 3,5-dihydroxytoluene (2), oleic acid (3), and penicillic acid (4) were discovered. Here, compounds 1 and 4 displayed anti-fungal activity against F. graminearum, F. oxysporum, F. moniliforme, F. stratum, Botrytis cinerea, Magnaporthe oryzae, and Verticillium dahliae with diverse MIC values (128–512 μg/ml), which were close to that of the positive control antifungal, actidione (64–128 μg/ml). Additionally, compounds 1 and 4 also exhibited moderate antibacterial activity against S. aureus, Listeria monocytogenes, Escherichia coli, and Salmonella enterica, with low MIC values (8–64 μg/ml). Moreover, compounds 1 and 4 displayed selective cytotoxicity against cancer cell lines as compared with the normal fibroblast cells. Therefore, this study proposes that the endophytic fungi from L. supina can potentially produce bioactive molecules to be used as lead compounds in drugs or agricultural antibiotics.