On-Line Prediction of Impulse Spark and Arc Discharge Removals of Metal Bond in Dry Electrical Discharge Dressing of Diamond Grinding Wheel

Yanjun Lu,Jiajing Sun,Xiaoyu Wu,Fumin Chen 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2

The electrical discharge is able to realize efficient dressing for metal-bonded diamond wheel, but the monitoring and prediction of dressing status have been technical bottleneck in industrialization. Hence, the metal bond removal model of impulse spark and arc discharges is proposed to realize on-line monitoring and prediction for micro grain protrusion on diamond grinding wheel surface. The relationship between microremovals of metal bond and impulse spark and arc discharge parameters was investigated for controllable dressing. First, the static and dynamic impulse discharge experiments were carried out to reveal metal bond removal mechanisms of impulse spark and arc discharges; then the relationship between characterized impulse discharge parameters and removal of metal bond was quantitatively analyzed; finally, the dry electro-contact discharge (ECD) dressed coarse diamond wheels were applied to perform smooth surface and mirror grinding of optical glass and mold steels against mechanical dressed wheels. It is found that the critical transition value of arc discharge to spark discharge under static discharge and dynamic discharge conditions were 0.059 and 0.038, respectively. In comparison with mechanical dressing, the dry ECD can obtain higher grain protrusion height to improve ground surface quality, leading to a microscopic smooth surface of BAK3 optical glass and macroscopic mirror-like surface of model steels. It is confirmed that the established relationship model can be effectively used to on-line predict the removal of metal bond with the average prediction error of 10.1% and microscopic grain protrusion by characterized impulse discharge parameters.

Proteomic Analysis of the Triglyceride-Rich Lipoprotein-Laden Foam Cells

Yanjun Lu,Jianli Guo,Yong Di,Yiqiang Zong,Shen Qu,Jun Tian 한국분자세포생물학회 2009 Molecules and cells Vol.28 No.3

In hypertriglyceridaemic individuals, atherosclerogenesis is associated with the increased concentrations of very low density lipoprotein (VLDL) and VLDL-associated rem-nant particles. In vitro studies have suggested that VLDL induces foam cells formation. To reveal the changes of the proteins expression in the process of foam cells formation induced by VLDL, we performed a proteomic analysis of the foam cells based on the stimulation of differentiated THP-1 cells with VLDL. Using two-dimensional gel electro-phoresis (2-DE) and matrix-assisted laser-desorption ioni-zation time-of-flight mass spectrometry (MALDI-TOF MS) analysis, 14 differentially expressed proteins, containing 8 up-regulated proteins and 6 down-regulated proteins were identified. The proteins are involved in energy metabolism, oxidative stress, cell growth, differentiation and apoptosis, such as adipose differentiation-related protein (ADRP), enolase, S100A11, heat shock protein 27 and so on. In addition, the expression of some selected proteins was confirmed by Western blot and RT-PCR analysis. The re-sults suggest that VLDL not only induces lipid accumula-tion, but also brings about foam cells diverse characteris-tics by altering the expression of various proteins.

Memristive effect with non-zero-crossing current-voltage hysteresis behavior based on Ag doped Lophatherum gracile Brongn

Yanjun Xu,Lu Tan,Bai Sun,Ming Lei,Yiluo Zhao,Tengteng Li,Liang Zheng,Shouhui Zhu,Yong Zhang,Yong Zhao 한국물리학회 2020 Current Applied Physics Vol.20 No.4

The memristive effect become a bio-electronics research focus with the development of sustainable systems and the application of multifunctional electronic devices. In this paper, the natural Lophatherum gracile Brongn (LGB) was employed as active layer to prepare Ag/LGB/fluorine-doped tin oxide (FTO) bio-memristor. Further, different doping ratios nano silver powders (Ag nanoparticle) were doped into LGB functional layers at 0 wt%, 0.2 wt%, 0.33 wt%, 1.0 wt%, 2.0 wt%, 10.0 wt% and 20.0 wt%. It is found that the capacitive-coupled memristive performance of the Ag/Ag-doped-LGB/FTO devices was markedly changed. Finally, it is confirmed that Ag ions transferring and Ag filament formation under the applied voltage are responsible for capacitive-coupled memristive behavior. This research has revealed the realization of capacitive-coupled memristive effect of biomemristor, which opens a new way to achieve multifunctional performance for electronic device.

MODEL PREDICTIVE TRAJECTORY OPTIMIZATION AND TRACKING IN HIGHLY CONSTRAINED ENVIRONMENTS

Lu Xiong,Zhiqiang Fu,Zixuan Qian,Bo Leng,Dequan Zeng,Yanjun Huang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

This paper presents a model predictive trajectory optimization and tracking framework to avoid collisions for autonomous vehicles in highly constrained environments. Firstly, a vehicle model is established in road coordinate system to describe the relationship between the vehicle and the reference road. Secondly, a numerical optimization method is applied to smoothen the reference path generated by waypoints. Then, a multilayer searched method is used to establish a safe driving corridor in highly constrained environments. In addition, an optimal path optimization and tracking framework based on model predictive control is formulated to improve the driving safety and comfort. The proposed framework considers the constraints of path boundaries and vehicle dynamics to provide the optimal control command. Furthermore, the speed profile is optimized based on the longitudinal motion model in space domain to ensure the constraints of speed limits and vehicle acceleration. Finally, the proposed algorithms are evaluated through experiments in various scenarios to demonstrate the effectiveness.

Analytical solution of seismic stability against overturning for a rock slope with water-filled tension crack

Zhang, Yanjun,Nian, Tingkai,Zheng, Defeng,Zheng, Lu Techno-Press 2016 Geomechanics & engineering Vol.11 No.4

Steep rock slope with water-filled tension crack will happen to overturn around the toe of the slope under seismic loading. This failure type is completely different from the common toppling failure occurring in anti-dipping layered rock mass slopes with steeply dipping discontinuities. This paper presents an analytical approach to determine the seismic factor of safety against overturning for an intact rock mass slope with water-filled tension crack considering horizontal and vertical seismic coefficients. This solution is a generalized explicit expression and is derived using the moment equilibrium approach. A numerical program based on discontinuous deformation analysis (DDA) is adopted to validate the analytical results. The parametric study is carried out to adequately investigate the effect of horizontal and vertical seismic coefficients on the overall stability against overturning for a saturated rock slope under two water pressure modes. The analytical results show that vertically upward seismic inertia force or/and second water pressure distribution mode will remarkably decrease the slope stability against overturning. Finally, several representative design charts of slopes also are presented for the practical application.

Functional Evaluation of Transplanted Kidneys with Reduced Field-of-View Diffusion-Weighted Imaging at 3T

Yuan Xie,Yanjun Li,Jiqiu Wen,Xue Li,Zhe Zhang,Jianrui Li,Yan’e Zhao,Peng Wang,Jun Zhang,Ying Tian,Long Jiang Zhang,Guang Ming Lu 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2

Objective: To determine the feasibility of reduced field-of-view diffusion-weighted imaging (rFOV DWI) with multi-b values to detect functional variability in transplanted kidneys. Materials and Methods: Using a 3T MRI scanner, multi-b rFOV DWI of transplanted kidney or native kidney was performed in 40 renal transplantation recipients and 18 healthy volunteers. The patients were stratified, according to an estimated glomerular filtration rate (eGFR): Group 1, eGFR ≥ 60 mL/min/1.73 m2; Group 2, eGFR ≥ 30 mL/min/1.73 m2 and < 60 mL/min/1.73 m2; Group 3, eGFR < 30 mL/min/1.73 m2. Total apparent diffusion coefficient (ADCT), perfusion-free ADC (ADCD) and perfusion fraction (FP) of kidneys were calculated and compared among the four groups. Correlations between the imaging results and eGFR were assessed. Results: All volunteers had eGFR ≥ 60 mL/min/1.73 m2, while 16, 16, and 8 patients were included in Groups 1, 2, and 3, respectively. In the renal cortex, ADCT was higher in Group 1 ([1.65 ± 0.13] x 10-3 mm2/s) than Group 3 ([1.44 ± 0.11] x 10-3 mm2/s) (p < 0.05), and the inter-group differences of FP values were significant (all p < 0.05) (0.330 ± 0.024, 0.309 ± 0.019, 0.278 ± 0.033, and 0.250 ± 0.028 for control group, Groups 1, 2, and 3, respectively). Renal cortical ADCT, ADCD, FP, and renal medullary ADCT and FP correlated positively with eGFR (r = 0.596, 0.403, 0.711, 0.341, and 0.323, respectively; all p < 0.05). When using 0.278 as the cutoff value, renal cortical FP had a sensitivity of 97.1% and a specificity of 66.7% for predicting decreased renal function. Conclusion: Multi-b rFOV DWI presents transplanted kidneys with high resolution, which is a promising functional tool for non-invasively monitoring function of transplanted kidneys.

Transcription factor Sp1 is necessary and functional in regulating expression of oncogene ZNF703

Xiaolin Liao,Yongjie Lu,Junbao Yang,Tao Kuang,Lilin Jiang,Yanjun Wang,Huiqun Kang,Bo Jiang,Xiaoli Zhou,Sheng He 한국유전학회 2017 Genes & Genomics Vol.39 No.10

Zinc finger protein 703 (ZNF703) is a putative oncogene in patients with the luminal B molecular subtype of breast cancer. Although the exact function of ZNF703 protein remains largely unknown, its expression and regulation have been implicated in several physiological and pathological processes. In the current study, for the first time, we identified and characterized the human ZNF703 gene promoter region. As a means of characterizing the transcription elements required for expression of ZNF703 protein at different stages, we cloned the promoter region of ZNF703 then created chimeric reporter plasmids for use in luciferase assays. A progressive deletion analysis of the ZNF703 gene’s 5′ and 3′ -flanking regions revealed that the core promoter is located in a 256-bp region ranging from nt-539 to nt-283. Next, we examined the effects of sitespecific mutations and treatment with mithramycin A to identify the functional Sp1 binding site, which was found to be located in a 447 bp region that ranged from nt-509 to nt-76, displayed the characteristics of a CpG island, and overlapped with the promoter region. In conclusion, our data suggest that ZNF703 transcription is regulated by transcription factor Sp1. This finding should facilitate future studies of the mechanism which regulates expression of this important gene.

Sound Recognition of Harmful Bird Species Related to Power Grid Faults Based on VGGish Transfer Learning

Qiu Zhibin,Wang Haixiang,Liao Caibo,Lu Zuwen,Kuang Yanjun 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

Bird activities threaten the safe operation of transmission lines and substations. In order to assist differentiated prevention of bird-related faults in power grid, this paper proposes a birdsong recognition method based on VGGish transfer learning. Firstly, according to the information of bird species related to historical power grid faults and the investigation results of bird species around transmission lines, 18 high-risk, 18 low-risk, and 2 harmless bird species were selected to establish a sample set with their song signals. Then, the birdsong signals were preprocessed by framing, windowing, noise reduction and clipping, thus to extract the spectrogram, which was mapped to a 64-order Mel filter banks to get the Mel spectrogram. Aiming at weak generalization ability of traditional birdsong recognition models due to insufficient number of samples, the VGGish transfer learning network pretrained by AudioSet was used as the birdsong feature extractor, and the Mel spectrograms of harmful bird species belong to the training set were taken as inputs to train the network parameters, thus to extract 128-dimensional VGGish deep features for bird recognition. This method was applied to classify 38 kinds of bird species related to power grid faults, and the recognition accuracy reaches 94.43%. The research results can provide references for power grid inspector to carry out intelligent recognition and ecological prevention of bird species.

Computational fluid dynamics simulation study of gas flow in dry vacuum pump

Xiangji YUE,Yingli ZHANG,Dechun BA,Yaoshuai BA,Yanjun LU,Guangyu WANG 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Rocaglamide-A Potentiates Osteoblast Differentiation by Inhibiting NF-κB Signaling

Li, Aiguo,Yang, Libin,Geng, Xiaolin,Peng, Xingmei,Lu, Tan,Deng, Yanjun,Dong, Yuzheng Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.11

Rheumatoid arthritis is a chronic inflammatory disease that leads to bone and cartilage erosion. The inhibition of osteoblast differentiation by the inflammatory factor TNF-${\alpha}$ is critical for the pathogenesis of rheumatoid arthritis. To modulate TNF-${\alpha}$ mediated inhibition of osteoblast differentiation is required to improve therapeutic efficacy of rheumatoid arthritis. Here, we explored the potential role of rocaglamide-A, a component of Aglaia plant, in osteoblast differentiation. Rocaglamide-A prevented TNF-${\alpha}$ mediated inhibition of osteoblast differentiation, and promoted osteoblast differentiation directly, in both C2C12 and primary mesenchymal stromal cells. Mechanistically, Rocaglamide-A inhibited the phosphorylation of NF-${\kappa}B$ component p65 protein and the accumulation of p65 in nucleus, which resulted in the diminished NF-${\kappa}B$ responsible transcriptional activity. Oppositely, overexpression of p65 reversed rocaglamide-A's protective effects on osteoblast differentiation. Collectively, rocaglamide-A protected and stimulated osteoblast differentiation via blocking NF-${\kappa}B$ pathway. It suggests that rocaglamide-A may be a good candidate to develop as therapeutic drug for rheumatoid arthritis associated bone loss diseases.