Dynamic analysis of 5-DOFs aerostatic spindles considering tilting motion with varying stiffness and damping of thrust bearings

Jiasheng Li,Pinkuan Liu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

Aerostatic bearings are of great importance for improving machining accuracy of a workpiece surface. The dynamics of air bearings and aerostatic spindle system in ultra-precision machine, which mainly causes mid-spatial waviness errors, has a great effect on surface topography. The dynamic coefficients of the thrust bearings were determined by adopting the perturbation method and finite difference method with MATLAB ® software. In addition, the influences of the spindle speed and tilt angle conducted upon the dynamics of the thrust bearings were investigated in detail. The dynamic response of the spindle system, which is closely related to the performance of the thrust bearing and does not work only by the effect of the journal bearing, supported by pressured air film was obtained. The simulation analysis of spindle responses under cutting force and experiment results is well matched, and the analysis method proposed in this paper can be also applicable to other air bearing spindle systems.

Association between PNPLA3 rs738409 polymorphism and hepatocellular carcinoma risk: an updated meta-analysis

Li Zhang,Chuanmiao Liu,Kuihua Xu,Jiasheng Chen 한국유전학회 2016 Genes & Genomics Vol.38 No.9

Hepatocellular carcinoma (HCC) is a common malignant tumor and the leading cause of cancer-related death worldwide. The protein encoded by patatin-like phospholipase domain-containing protein 3 (PNPLA3) plays important roles in liver fatty metabolism. Recent studies have indicated associations of PNPLA3 rs738409 with various liver diseases, including HCC. This metaanalysis was performed to investigate and update the association between rs738409 polymorphism and the risk of HCC, and to test the association between rs738409 and HCC specifically in patients within chronic hepatitis B and/ or C infection, alcoholic liver disease, or other diseases. Studies were searched from the literature database up to March 31, 2016. The meta-analysis was conducted based on statement of preferred reporting items for systematic reviews and meta-analyses. Pooled odds ratios (OR) and 95 % confidence intervals (CI) were estimated the strength of associations between rs738409 polymorphism and HCC risk. Fifteen published studies, consisting of 2264 HCC patients (case) and 5802 without HCC individuals (control), were included in the present study. Meta-analysis revealed that rs738409 polymorphism contributed to HCC risk under the allelic effect model (C vs. G: OR 1.73; 95 % CI 1.53–1.96), the dominant effect model (CC vs. CG?GG: OR 1.61; 95 % CI 1.44–1.81), and the recessive effect model (CC?CG vs. GG: OR 2.66; 95 % CI 2.28–3.11). Furthermore, the effect of rs738409 G allele on liver oncogenesis was higher in alcoholic liver disease (OR 2.55), compared to chronic hepatitis C/B (OR 1.32) and other diseases (OR 2.27). The results suggested that rs738409 polymorphism was significantly associated with HCC risk and it could be used as one risk factor for HCC.

Association between STAT4 polymorphisms and risk of primary biliary cholangitis: a meta-analysis

Li Zhang,Chunming Gao,Chuanmiao Liu,Jiasheng Chen,Kuihua Xu 한국유전학회 2018 Genes & Genomics Vol.40 No.10

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease. Several studies reported that SATA4 (signal transducer and activator of transcription 4) polymorphisms were significantly associated with PBC susceptibility. In order to derive a more comprehensive estimation of the association between STAT4 and PBC risk, this meta-analysis was conducted. Thirteen eligible studies from 8 articles with a total number of 11,310 cases and 27,844 controls were included in this meta-analysis. Pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated with fixed effects model or random effects model. The results showed statistically significant association between polymorphisms of rs7574865, rs3024921, rs6752770, rs7601754 and rs10168266 in STAT4 and PBC risk under the allelic effect model (rs7574865, T vs. G, OR = 1.24, 95% CI 1.14–1.35; rs3024921, T vs. A, OR = 1.65, 95% CI 1.44–1.91; rs6752770, G vs. A, OR = 1.24, 95% CI 1.11–1.39; rs7601754, A vs. G, OR = 1.35, 95% CI 1.17–1.55; and rs10168266, T vs. C, OR = 1.31, 95% CI 1.22–1.41). Furthermore, the rs7574865 polymorphism was significantly associated with PBC risk under all genotype genetic models (dominant effect model: TT + TG vs. GG, OR = 1.43, 95% CI 1.19–1.71; recessive effect: TT vs. TG + GG, OR = 1.40, 95% CI 1.24–1.58; and co-dominant effect: TT vs. GG, OR = 1.67, 95% CI 1.37–2.02). The sensitivity analysis by omitting one study at a time showed that the results were stable. No publication bias was indicated from both Begg’s test and Egger’s weighted regression. This meta-analysis suggested that polymorphisms of rs7574865, rs3024921, rs6752770, rs7601754 and rs10168266 in STAT4 were significantly associated with the risk of PBC.

Sensitive detection of levofloxacin and copper (II) based on fluorescence ‘‘turn on-off” of biomass carbonized polymer dots

Jiasheng Lin,Shuliang Yang,Yanjie Wang,Yahan Cui,Qiaoyan Li,Yanhua Chen,Lan Ding 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

A novel type of biomass carbonized polymer dots (CS-CPDs) with green fluorescence emission were synthesizedvia a one-step microwave-assisted method, using chitosan and maleic acid as the precursors. The fluorescence intensity of CS-CPDs was selectively enhanced (turn on) with increasing levofloxacin(LEV) concentration based on Aggregation Induced Emission Enhancement. The linear range of thismethod was 1–35 lmol/L, with the limit of detection of 0.20 lmol/L. Furthermore, we demonstrated thatthe fluorescence intensity of CS-CPDs/LEV was restored (turn on-off) due to the addition of copper (II),which could assemble a more stable Cu2+/LEV complex through coordination. For the first time, CSCPDswere utilized as a selective fluorescent ‘‘turn on-off” probe for the continuous detection of LEVand Cu2+. Excellent results were also obtained in environmental water samples analysis with recoveriesranging of 91.3–99.6% and 97.7–113.4%, respectively. Moreover, the prepared CS-CPDs exhibited excellentoptical stability and large Stokes shift (139 nm), which predicted broad application prospects inthe field of fluorescence sensing.

Synthesis of carbon microsphere-assisted snowflake-like ZnO nanomaterials for selective detection of NO2 at room temperature

Qiaoyan Li,Yahan Cui,Jiasheng Lin,Chun Zhao,Lan Ding 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

In this paper, the snowflake-like ZnO nanomaterials were prepared by combining zinc salt impregnationand high-temperature calcination with carbon microspheres as the sacrificial template. The effects ofethanol concentration in aqueous solution on the microstructure and sensing properties of ZnO nanomaterialswere investigated. The results showed that using 25 % ethanol-containing aqueous solution asimpregnation solution, snowflake-like ZnO nanomaterials (ZnO-25) showed excellent sensing performancefor NO2 at room temperature. It is mainly attributable to the rich channels and large specific surfacearea of the snowflake-like ZnO, which facilitates the rapid diffusion of the target gas. A large amountof chemisorbed oxygen can promote the surface reaction. In addition, the unremoved carbon during calcinationpromotes the electrical properties of ZnO. This strategy will provide a new sight on developing atype of sensitive NO2 gas sensing device working at room temperature.

Modeling identification and control of a 6-DOF active vibration isolation system driving by voice coil motors with a Halbach array magnet

Dawei Jiang,Jiasheng Li,Xingzhan Li,Chaodong Deng,Pinkuan Liu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

The sheet current model considering the end effects is applied to design a sixdegree-of-freedom (6-DOF) active vibration isolation system (AVIS) driving by the voice coil motors (VCMs). Compared with the charge model, the sheet current method represents higher calculation efficiency. Then, the hybrid functions (HFs) are employed to identify the multi-input and multi-output (MIMO) AVIS, and the identification parameters are used to design the controller. To promote the control performance, the composite nonlinear feedback (CNF) controller is designed based on the identification parameters. Consequently, the simulations and experiments are carried out, compared with PID controller, the CNF controller shows quicker response and smaller overshoot, i.e., the CNF controller achieves the dynamic damping ratio during the control. Thus, the experimental results demonstrate the better performance of the CNF controller.

Targeted capture enrichment and sequencing identifies HLA variants associated with the severity of COVID-19

Liu Chuanmiao,Zhang Li,Chen Jiasheng,Gao Yu 한국유전학회 2023 Genes & Genomics Vol.45 No.4

Background Coronavirus disease 2019 (COVID-19) is currently a global pandemic. The pathogenesis of severe COVID-19 has been widely investigated, but it is still unclear. Human leukocyte antigen (HLA) plays a central role in immune response, and its variants might be related to COVID-19 progression and severity. Objective To investigate the hypothesis that individual HLA variations could alter the course of COVID-19 and might be associated with the severity of COVID-19. Methods In this study, we conducted an HLA targeted capture enrichment and sequencing of severe COVID-19 patients matched to mild cases. A total of 16 COVID-19 patients, confirmed by SARS-CoV-2 viral RNA polymerase-chain-reaction (PCR) test and chest computed tomography (CT) scan, were enrolled in this study. The HLA targeted capture enrichment and sequencing were conducted. HLA typing was performed by comparing contigs with IPD-IMGT/HLA Database. Results In this study, 139 four-digit resolution HLA alleles were acquired. The results showed that HLA-DRB3*01:01 allele was significantly associated with the severity of COVID-19 (odds ratio [OR] = 27.64, 95% confidence interval [CI] = 1.35–560.50, P = 0.0064). And HLA-K*01:01 might be a potential risk factor for COVID-19 severity (OR = 0.11, 95% CI = 0.017–0.66, P = 0.019), but HLA-K*01:02 might be a protective factor (OR = 7.50, 95% CI = 1.48–37.92, P = 0.019). Conclusion Three non-classical HLA alleles, including HLA-DRB3*01:01, HLA-K*01:01, HLA-K*01:02 were identified to be associated with the severity of COVID-19 by comparing mild and severe patients. The current findings would be helpful for exploring the influence of HLA gene polymorphisms on the development and severity of COVID-19.

Compressive resistance behavior of UHPFRC encased steel composite stub column

Zhenyu Huang,Xinxiong Huang,Weiwen Li,Jiasheng Zhang 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.2

To explore the feasibility of eliminating the longitudinal rebars and stirrups by using ultra-high-performance fiber reinforcement concrete (UHPFRC) in concrete encased steel composite stub column, compressive behavior of UHPFRC encased steel stub column has been experimentally investigated. Effect of concrete types (normal strength concrete, high strength concrete and UHPFRC), fiber fractions, and transverse reinforcement ratio on failure mode, ductility behavior and axial compressive resistance of composite columns have been quantified through axial compression tests. The experimental results show that concrete encased composite columns with NSC and HSC exhibit concrete crushing and spalling failure, respectively, while composite columns using UHPFRC exhibit concrete spitting and no concrete spalling is observed after failure. The incorporation of steel fiber as micro reinforcement significantly improves the concrete toughness, restrains the crack propagation and thus avoids the concrete spalling. No evidence of local buckling of rebars or yielding of stirrups has been detected in composite columns using UHPFRC. Steel fibers improve the bond strength between the concrete and, rebars and core shaped steel which contribute to the improvement of confining pressure on concrete. Three prediction models in Eurocode 4, AISC 360 and JGJ 138 and a proposed toughness index (T.I.) are employed to evaluate the compressive resistance and post peak ductility of the composite columns. It is found that all these three models predict close the compressive resistance of UHPFRC encased composite columns with/without the transverse reinforcement. UHPFRC encased composite columns can achieve a comparable level of ductility with the reinforced concrete (RC) columns using normal strength concrete. In terms of compressive resistance behavior, the feasibility of UHPFRC encased steel composite stub columns with lesser longitudinal reinforcement and stirrups has been verified in this study.

The complete mitochondrial genome of Hemigrapsus sinensis (Brachyura, Grapsoidea, Varunidae) and its phylogenetic position within Grapsoidea

Jin Xun,Guo Xingle,Chen Jian,Li Jiasheng,Zhang Shufei,Zheng Sixu,Wang Yunpeng,Peng Ying,Zhang Kun,Liu Yifan,Liu Bingjian 한국유전학회 2023 Genes & Genomics Vol.45 No.3

Background In this study, the complete mitogenome of Hemigrapsus sinensis was the first identified and analyzed. Objective The complete mitochondrial genome of Hemigrapsus sinensis (Brachyura, Grapsoidea, Varunidae) and its phylogenetic position within Grapsoidea. Methods The sample of Hemigrapsus sinensis was collected and DNA was extracted. After sequencing, NOVOPlasty was used for sequence assembly. Annotate sequences with MITOS WebServer, tRNAscan-SE2.0, and NCBI database. MEGA was used for sequence analysis and Phylosuite was used for phylogenetic tree construction. DnaSP was used to calculate Ka/Ks. Results This mitochondrial genome shows that it was 15,900 bp and encoded 13 PCGs, 22 tRNA genes, two rRNA genes, and one control region. The genome composition tends to A + T (74.34%) and presents a negative GC-skew (− 0.22) and AT-skew (− 0.03). The PCGs initiation codon was the typical ATN and termination codon was the typical TAN, incomplete T or missing. The ML and BI trees showed that H. sinensis was most closely related to Hemigrapsus and clustered together with the Varunidae. And our phylogenetic trees provide proof that Ocypodoidea and Grapsoidea may be of common origin. Meanwhile, in the phylogenetic tree, parallel mixing of Chiromantes and Orisarma raised doubts over the traditional classification system. Besides, Incomplete Lineage sorting (ILS) was observed in Varunidae. In the subsequent analysis of evolution rate, we found that all of the PCGs (NAD4 was not calculated) had undergone negative selections, indicating the conservation of mitochondrial genes of H. sinensis during the evolution. Conclusion Therefore, researching the complete mitogenome of H. sinensis would be contributing to molecular taxonomy, phylogenetic relationship, and breeding optimization within the Grapsoidea superfamily.

Effect of Different Nanofillers on Non-Isothermal Crystallization Kinetics and Electric Conductivity of Dynamically-Vulcanized PP-EPDM Blends

Bin Yang,Lei Hu,Ru Xia,Fang Chen,Shu-Chun Zhao,Yan-Li Deng,Ming Cao,Jiasheng Qian,Peng Chen 한국고분자학회 2016 Macromolecular Research Vol.24 No.1

In this study, nanofillers composed of hydroxylated carbon nanotubes (h-CNT), carbon nanotubes (CNT) and graphene (GR) were separately added into the dynamically-vulcanized polypropylene (PP)/ethylene-propylenediene monomer (EPDM) blend. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and electrical resistivity measurements were employed to study the effect of nanofillers on the melt behavior, non-isothermal crystallization behavior and electrical conductivity of the prepared composites. WAXD results showed that h-CNT had a better induction effect of β-PP in the nanocomposites. The sequence of the activity in inducing the formation of β-PP was h-CNT>GR>CNT. However, the total crystallinity of the nanocomposites nearly remained constant. Non-isothermal crystallization kinetic analysis indicated that the presence of nanofillers improved the crystallization rate of the nanocomposites. The consequence of nucleation activity was as follows: CNT>GR>h-CNT. Although EPDM hindered the macromolecular motion of PP, interestingly it could increase the crystallization rate to an extent. Besides, the influence of nanofillers on enhancing the conductive property of the nanocomposites can be ranked as follow: CNT>GR>h-CNT.