The cricket genus Vietacheta Gorochov, 1992 (Gryllidae, Gryllinae) with description of a new species from China

Libin Ma,Yang Liu,Sheng-Quan Xu 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.4

Vietacheta, a cricket genus found across northern and southern Vietnam, is a rare taxon lacking any additional species discovered after the genus was established. This genus possesses features found across many other genera. Its general appearance is the same as Itaropsis; genitalia ectoparamere is very similar to Phonarellus; inner tympanum is absent, and particularly, the metanotum is armed with several hairs. Now, we found the first species of Vietacheta in China. The new species, Vietacheta harpophylla sp. nov., is close to Vietacheta aquila Gorochov, 1992, but they are different in details of anal plate, epiphallus, and ectoparamere. A description and illustration of this new species, a revision of other Vietacheta, and a key to the genus are provided.

Pneumococcal wall teichoic acid is required for the pathogenesis of Streptococcus pneumoniae in murine models

Hongmei Xu,Libin Wang,Jian Huang,YanQing Zhang,Feng Ma,Jianmin Wang,WenChun Xu,XueMei Zhang,YiBing Yin,KaiFeng Wu 한국미생물학회 2015 The journal of microbiology Vol.53 No.2

Pneumococcal asymptomatic colonization of the respiratory tracts is a major risk for invasive pneumococcal disease. We have previously shown that pneumococcal wall teichoic acid (WTA) was involved in pneumococcal infection of sepsis and adherence to epithelial and endothelial cells. In this study, we investigated the contribution of pneumococcal WTA to bacterial colonization and dissemination in murine models. The result showed that nasopharynx colonizing D39 bacterial cells have a distinct phenotype showing an increased exposure of teichoic acids relative to medium-grown bacteria. The WTA-deficient mutants were impaired in their colonization to the nasopharynx and lungs, and led to a mild inflammation in the lungs at 36 h post-inoculation. Pretreatment of the murine nares with WTA reduced the ability of wild type D39 bacteria to colonize the nasopharynx. In addition, the WTA-deficient strain was impaired in its ability to invade the blood and brain following intranasal administration. WTA-deficient D39 strain was reduced in C3 deposition but was more susceptible to the killing by the neutrophils as compared with its parent strain. Our results also demonstrated that the WTA enhanced pneumococcal colonization and dissemination independently of the host strains. These results indicate that WTA plays an important role in pneumococcal pathogenesis, both in colonization and dissemination processes.

Effects of the Nonequilibrium Model and the Discharge Frequency on an Argon Inductively Coupled Plasma Simulation

Minghao Yu,Libin Ma,Kai Liu 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.2

Numerical simulations of argon inductively coupled plasmas (ICPs) were carried out by using the magneto-hydrodynamic equations and considering the different thermodynamic models inside the 10-kW ICP torch. The distribution characteristics of the flow velocity and the temperature were obtained and analyzed under thermodynamic equilibrium and nonequilibrium conditions, respectively. The effects of different typical discharge frequencies on the flow-field properties of the nonequilibrium argon ICP flow were also studied. The results indicate that the temperature distribution simulated by using the nonequilibrium model is more consistent with the experimental data than the one modeled by using the equilibrium model. The higher the discharge frequency is, the lower the maximum velocity and temperature of the nonequilibrium ICP flow are found to be.

An improved bearing fault diagnosis method based on variational mode decomposition and adaptive iterative filtering (VMD-AIF)

Lei Fu,Zepeng Ma,Yikun Zhang,Sinian Wang,Libin Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Rolling bearings are widely applied in rotary machines. Bearing failures can lead to long machine downtime and costly maintenance. To reduce the maintenance time and cost, this article proposes a new denoising approach to remove heavy noise and extract weak bearing fault vibration features. The first step proposes a global variational mode decomposition (VMD) optimization algorithm that adaptively matches the optimal decomposition parameters based on kurtosis. In the second step, an adaptive selection criterion for IMF is developed by kurtosis theory. Meanwhile, an adaptive termination criterion is established based on sample entropy (SampEn), and the fault features are extracted with a Butterworth band-pass filter (BBF). Finally, actual fault-bearing experiments are performed using the proposed denoising approach. The comparison with respect to EEMD and WPD is illustrated in detail. The experimental result shows that the proposed approach is a validated tool for the diagnosis of bearings.

Constructing Negative Links from Multi-facet of Social Media

( Lin Li ),( Yunyi Yan ),( Libin Jia ),( Jun Ma ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.5

Various types of social media make the people share their personal experience in different ways. In some social networking sites. Some users post their reviews, some users can support these reviews with comments, and some users just rate the reviews as kind of support or not. Unfortunately, there is rare explicit negative comments towards other reviews. This means if there is a link between two users, it must be positive link. Apparently, the negative link is invisible in these social network. Or in other word, the negative links are redundant to positive links. In this work, we first discuss the feature extraction from social media data and propose new method to compute the distance between each pair of comments or reviews on social media. Then we investigate whether we can predict negative links via regression analysis when only positive links are manifested from social media data. In particular, we provide a principled way to mathematically incorporate multi-facet data in a novel framework, Constructing Negative Links, CsNL to predict negative links for discovering the hidden information. Additionally, we investigate the ways of solution to general negative link predication problems with CsNL and its extension. Experiments are performed on real-world data and results show that negative links is predictable with multi-facet of social media data by the proposed framework CsNL. Essentially, high prediction accuracy suggests that negative links are redundant to positive links. Further experiments are performed to evaluate coefficients on different kernels. The results show that user generated content dominates the prediction performance of CsNL.

Investigating the effects of confining pressure on graphite material failure modes and strength criteria

Yi Yanan,Liu Guangyan,Xing Tongzhen,Lin Guang,Sun Libin,Shi Li,Ma Shaopeng 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

As a critical material in very/high-temperature gas-cooled reactors, graphite material directly affects the safety of the reactor core structures. Owing to the complex structures of graphite material in reactors, the material typically undergoes complex stress states. It is, therefore, necessary to study its mechanical properties, failure modes, and strength criteria under complex stress states so as to provide guidance for the core structure design. In this study, compressive failure tests were performed for graphite material under the condition of different confining pressures, and the effects of confining pressure on the triaxial compressive strength and Young's modulus of graphite material were studied. More specifically, graphite material based on the fracture surfaces and fracture angles, the graphite specimens were found to exhibit four types of failure modes, i.e., tension failure, shear-tension failure, tension-shear failure and shear failure, with increasing confining pressure. In addition, the Mohr strength envelope of the graphite material was obtained, and different strength criteria were compared. It showed that the parabolic MohrCoulomb criterion is more suitable for the strength evaluation for the graphite material.

In-Plane Dynamics Characteristics and Multi-Objective Optimization of Negative Poisson’s Ratio Honeycomb Structure with Power Function Curve

Zhu Yifan,Xu Feng Xiang,Guan Yijie,Zou Zhen,Duan Libin,Du Zhanpeng,Ma Hongfeng 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.5

As an alternative to the conventional concave hexagonal honeycomb structure (CHHS), a negative Poisson’s ratio honeycomb structure with power function curve (NHPC) was devised. The relationship between the power function exponent (PFE) and normalized power function coefficient (NPFC) of honeycomb structure and its equivalent Poisson’s ratio (EPR) was explored to identify the range of variables required for the negative Poisson’s ratio effect. To investigate the in-plane mechanical properties and energy absorption characteristics of NHPC, the deformation mode, dynamic response, and energy absorption characteristics under various impact velocities were studied by constructing an in-plane impact simulation model. The results showed that NHPC obviously exhibited a negative Poisson’s ratio effect on medium and low impact velocities, and the deformation was primarily uniform. As the NPFC increased, the honeycomb structure was less prone to stress concentration, while the peak crushing force (PCF) and the specific energy absorption (SEA) declined and the plateau stress increased. A multi-objective optimization experiment was operated with low PCF and high SEA as the targets within the range of design variables in order to generate the optimal NHPC. According to the experimental findings, the improved NHPC showed a 25.48 % reduction in PCF and a 19.29 % increase in SEA. This paper provides theoretical recommendations for improving the energy absorption and structural optimization of the honeycomb structure.

Study on failure mechanism of line contact structures of nuclear graphite

Jia Shigang,Yi Yanan,Wang Lu,Liu Guangyan,Ma Qinwei,Sun Libin,Shi Li,Ma Shaopeng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

Line contact structures, such as the contact between graphite brick and graphite tenon, widely exist in high-temperature gas-cooled reactors. Due to the stress concentration effect, the line contact area is one of the dangerous positions prone to failure in the nuclear reactor core. In this paper, the failure mechanism of line contact structures composed of IG11 nuclear graphite column and brick were investigated by means of experiment and finite element simulation. It was found that the failure process mainly includes three stages: firstly, the damage accumulation in nuclear graphite material led to the characteristic yielding of the line contact structure, but no macroscopic failure can be observed at this stage; secondly, the stresses near the contact area met Mohr failure criterion, and a crack initiated and propagated laterally in the contact zone, that is, local macroscopic failure occurred at this stage; finally, a second crack initiated in the contact area and developed in to a Y-shape, resulting in the final failure of the structure. This study lays a foundation for the structural design and safety assessment of hightemperature gas-cooled reactors

Physicochemical, Antibacterial Properties, and Compatibility of ZnO-NP/Chitosan/β-Glycerophosphate Composite Hydrogels

( Pingping Huang ),( Wen Su ),( Rui Han ),( Hao Lin ),( Jing Yang ),( Libin Xu ),( Lei Ma ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.4

In this study we aimed to develop novel ZnO-NP/chitosan/β-glycerophosphate (ZnO-NP/CS/β-GP) antibacterial hydrogels for biomedical applications. According to the mass fraction ratio of ZnO-NPs to chitosan, mixtures of 1, 3, and 5% ZnO-NPs/CS/β-GP were prepared. Using the test-tube inversion method, scanning electron microscopy and Fourier-transform infrared spectroscopy, the influence of ZnO-NPs on gelation time, chemical composition, and cross-sectional microstructures were evaluated. Adding ZnO-NPs significantly improved the hydrogel's antibacterial activity as determined by bacteriostatic zone and colony counting. The hydrogel's bacteriostatic mechanism was investigated using live/dead fluorescent staining and scanning electron microscopy. In addition, crystal violet staining and MTT assay demonstrated that ZnO-NPs/CS/β-GP exhibited good antibacterial activity in inhibiting the formation of biofilms and eradicating existing biofilms. CCK-8 and live/dead cell staining methods revealed that the cell viability of gingival fibroblasts (L929) cocultured with hydrogel in each group was above 90% after 24, 48, and 72 h. These results suggest that ZnO-NPs improve the temperature sensitivity and bacteriostatic performance of chitosan/β-glycerophosphate (CS/β-GP), which could be injected into the periodontal pocket in solution form and quickly transformed into hydrogel adhesion on the gingiva, allowing for a straightforward and convenient procedure. In conclusion, ZnO-NP/CS/β-GP thermosensitive hydrogels could be expected to be utilized as adjuvant drugs for clinical prevention and treatment of peri-implant inflammation.