Study on the progressive forming mechanism of multi-step shafts based on convex-end billet in the cross wedge rolling technology

Sutao Han,Xuedao Shu,Taizhu Chen,Ying Chang,Ji Chen,Xing Chen,Wei Xiang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.12

The deforming process is complicated and both the end concave and the central defect can be easily formed in multi-step shafts shaped by the cross-wedge rolling technology. To realize the accurate forming of multi-step shafts without stub bar, this article breaks the bondage of traditional flat-end billet, and introduces into convex-end billet. Based on established mechanical models and the damage computation principles, the distribution and change features of stress fields, strain fields and microstructures in different segments of the multistep shaft during the progressive forming process are analyzed, and the location of the central defect is predicted. It is found that the concave depth of shaft ends decreases as the length of the convex-end of billet increases, the microcosmic grains are affected by the section shrinkage of the shaft segments and the larger the section shrinkage is, the smaller the size of the microcosmic grain will be. It records the longest duration of maximum stress, the largest fluctuation of lateral stress and the most frequent cycle of transverse strain in the multistep shaft end and therefore the central defect is most likely to occur. The research findings settle a dependable theoretical basis for enhancing the molding quality and realizing the accurate forming for multi-step shafts in cross wedge rolling.

Over-expression of GmHAL3 modulates salt stresses tolerance in transgenic arabidopsis

Na Guo,Ming-xia Wang,Chen-chen Xue,Dong Xue,Jin-yan Xu,Hai-tang Wang,Jun-Yi Gai,Han Xing,Jin-ming Zhao;Han Xing 한국식물학회 2016 Journal of Plant Biology Vol.59 No.5

The halotolerance protein HAL3, also known as SIS2, is a yeast protein that regulates the cell cycle and tolerance to salt stress through inhibition of the Ppz1 type 1 protein phosphatase. Although the roles of HAL3 have been demonstrated during the growth, development, and stress adaptation of Arabidopsis thaliana and Nicotiana tabacum, the function of HAL3 in other plant species, including soybean (Glycine max), has not been elucidated. In this study, GmHAL3a and GmHAL3b were isolated from Glycine max, and their roles were analyzed. GmHAL3a and GmHAL3b transcripts were detected in the roots, stems, leaves and seeds, with higher levels in the roots, and were induced by sodium chloride (NaCl), lithium chloride (LiCl), sorbitol, cold and ABA treatment. Overexpression of GmHAL3a or GmHAL3b in Arabidopsis accelerated the onset of flowering and resulted in more vigorous seed germination and increased tolerance to NaCl, LiCl, and sorbitol stress in seedlings, compared with wild type (WT) and empty vector control (VC) plants. Transgenic Arabidopsis plants accumulated proline and eliminated superoxide radical (O2 −) in response to the stress. In addition, transcription levels of the stress-related genes RD22 and P5CS1 were substantially higher in transgenic Arabidopsis than in WT and VC plants. Taken together, the data indicate that GmHAL functions as a positive regulator of the response to salt, lithium cations and sorbitol stress.

Relation between the local structure and solid solubility of the layered material LiMO2 (M=Co, Ni, Fe) in Li2MnO3

Chen Hou,Xiang Xiao,Yi-Ran Xing,Le-Le Yu,Yong-Heng Si,Han Lu,Yu-Juan Zhao 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.1

Although low solid solubility and activity of LiFeO2in xLi2MnO3·(1–x)LiFeO2 limit its practical application, it still has thepotential to become a new-generation cathode material without cobalt or nickel for Li-ion batteries. In order to understand theeffects of the local structures of different LiMO2(M = Co, Ni, Fe) layered materials on their solid solubility in Li2MnO3,partialdensities of states are calculated to determine the Jahn–Teller distortion in the layered cathode material, and the first-principlescalculation method based on density functional theory is used to optimize and compare the local structures of LiCoO2,LiNiO2,LiFeO2,LiMnO2,and Li2MnO3. The degrees of distortion of the transition metal–oxygen (M–O) and lithium–oxygen (Li–O)octahedra in the crystal structure of the material are evaluated. It is clear that the solid solubility of layered materials is relatedto the bond lengths and degrees of distortion of the M–O and Li–O octahedra. Among them, the similar bond length of LiNiO2and Li2MnO3and the high distortion of NiO6enhance the solid solubility of LiNiO2in Li2MnO3. Owing to the absence ofJahn–Teller distortion in LiFeO2and LiCoO2,the FeO6and CoO6octahedra are slightly distorted, thereby decreasing thesolid solubility of LiMO2(M = Fe, Co) in Li2MnO3. Understanding the relation between intra-octahedral distortion and solidsolubility provides simple and efficient evidence for comparing the solid solubilities of different LiMO2layered materials inthe Li2MnO3of Li-rich cathode materials. This study can be used as a reference for component design in Li-rich materials.

Effects of Acute Sacral Neuromodulation at Different Frequencies on Bladder Overactivity in Pigs

Xing Li,Limin Liao,Guoqing Chen,Zhaoxia Wang,Han Deng 대한배뇨장애요실금학회 2017 International Neurourology Journal Vol.21 No.2

Purpose: We investigated the effects of different stimulation frequencies on the inhibition of bladder overactivity by sacral neuromodulation (SNM) in pigs. Methods: Implant-driven stimulators were used to stimulate the S3 spinal nerve in 13 pigs. Cystometry was performed by infusing normal saline (NS) or acetic acid (AA). SNM (pulse width, 210 μsec) at frequencies ranging from 5 to 50 Hz was conducted at the intensity threshold at which observable perianal and/or tail movement was induced. Multiple cystometrograms were performed to determine the effects of different frequencies on the micturition reflex. Results: AA-induced bladder overactivity significantly reduced the bladder capacity (BC) to 34.4%±4.7% of the NS control level (354.4±35.9 mL) (P<0.05). During AA infusion, SNM at 5 Hz did not significantly change the BC (48.1%±6.9% of the NS control level) (P>0.05), but SNM at 15, 30, and 50 Hz significantly increased the BC to 54.5%±7.1%, 55.2%±6.5%, and 57.2%±6.1% of the NS control level (P<0.05), respectively. No significant differences were found among the results obtained using frequencies of 15, 30, and 50 Hz (P>0.05). Conclusions: This study demonstrated that 15 Hz was an appropriate frequency for SNM and that frequencies higher than 15 Hz did not lead to better surgical outcomes.

Utilizing bee foraging behavior in mutational salp swarm for feature selection: a study on return-intentions of overseas Chinese after COVID-19

Xing Jie,Zhao Qinqin,Chen Huiling,Zhang Yili,Zhou Feng,Zhao Hanli 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

We present a bee foraging behavior-driven mutational salp swarm algorithm (BMSSA) based on an improved bee foraging strategy and an unscented mutation strategy. The improved bee foraging strategy is leveraged in the follower location update phase to break the fixed range search of salp swarm algorithm, while the unscented mutation strategy on the optimal solution is employed to enhance the quality of the optimal solution. Extensive experimental results on public CEC 2014 benchmark functions validate that the proposed BMSSA performs better than nine well-known metaheuristic methods and seven state-of-the-art algorithms. The binary BMSSA (bBMSSA) algorithm is further proposed for feature selection by using BMSSA as the selection strategy and support vector machine as the classifier. Experimental comparisons on 12 UCI datasets demonstrate the superiority of bBMSSA. Finally, we collected a dataset on the return-intentions of overseas Chinese after coronavirus disease (COVID-19) through an anonymous online questionnaire and performed a case study by setting up a bBMSSA-based feature selection optimization model. The outcomes manifest that the bBMSSA-based feature selection model exhibits a conspicuous prowess, attaining an accuracy exceeding 93%. The case study shows that the development prospects, the family and job in the place of residence, seeking opportunities in China, and the possible time to return to China are the critical factors influencing the willingness to return to China after COVID-19.

Centrifuge Model Tests and Numerical Simulations of the Landslide Evolution Process

Han-Dong Liu,Jia-Xing Chen,Wen-Xi Han,Ye Wu,Dong-Dong Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.6

Centrifuge model tests and numerical simulations were performed to study the landslide evolution process and failure mechanism. A TLJ-500 geotechnical centrifuge was used for the experiments and landslide deformation and stress was monitored using high-precision differential displacement sensors and earth pressure micro-sensors. Discrete element numerical simulations were performed using PFC2D based on the experimental results. The findings show that the landslide evolution process can be divided into three stages: 1) compaction and consolidation; 2) uniform deformation; and 3) accelerated deformation and failure. The numerical simulation results verify the distinct stage characteristics of the landslide evolution process. According to the migration of microscopic soil mass particles within the landslide, stage 3) can be further divided into a deformation development stage and instability and failure stage. The simulation displacement monitoring curves and displacement map show distinct deformation characteristics and displacement indicators from stages 2) to 3) and from the deformation development stage to the instability and failure stage. The experimental and numerical results reveal the landslide failure mechanism: the upper part of the landslide thrusts and slides; the middle part squeezes; the lower part collapses; and shear plane penetration leads to landslide failure.

Clinicopathologic and Prognostic Significance of the Zinc Finger of the Cerebellum Family in Invasive Breast Cancer

Wei Han,Cong Zhang,Xiao-jiao Gao,Hua-bing Wang,Fang Chen,Fang Cao,Yong-wei Hu,Jun Ma,Xing Gu,Hou-zhong Ding 한국유방암학회 2018 Journal of breast cancer Vol.21 No.1

Purpose: Five members of the zinc finger of the cerebellum (ZIC) family—ZIC1, ZIC2, ZIC3, ZIC4, and ZIC5—have been shown to be involved in various carcinomas. Here, we aimed to explore the clinicopathologic and prognostic roles of ZIC family members in invasive breast cancer patients using immunohistochemical analysis, western blotting analysis, and real-time quantitative polymerase chain reaction (RT-qPCR). Methods: A total of 241 female invasive breast cancer patients who underwent radical mastectomy between 2009 and 2011 were enrolled. ZIC proteins in 241 pairs of breast tumors and corresponding normal tissues were investigated using immunohistochemistry and the clinicopathologic roles of proteins were analyzed using Pearson’s chi-square test. Kaplan-Meier curves and Cox regression analysis were also used to analyze the prognostic value of the ZIC proteins. In addition, 12 pairs of fresh-frozen breast tumors and matched normal tissues were used in the western blotting analysis and RT-qPCR. Results: Only ZIC1 expression in normal tissues was obviously higher than that in tumors (p<0.001). On multivariate analysis, ZIC1 expression (in overall survival analysis: hazard ratio [HR], 0.405, 95% confidence interval [CI], 0.233–0.702, p=0.001; in disease-free survival analysis: HR, 0.395, 95% CI, 0.234–0.669, p=0.001) was identified as a prognostic indicator of invasive breast cancer. Conclusion: ZIC1, but not the other proteins, was obviously decreased in breast tumors and associated with clinicopathologic factors. Thus, ZIC1 might be a novel indicator to predict the overall and disease-free survival of invasive breast cancer patients.

HVOF Spray Performance Optimization Analysis and Experimental Research of WC–12Co Coating on Ti Alloy

Xinxue Chen,Chang Li,Siyu Li,Xing Han,Haisheng Jiang,Xiaoyu Zhao 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

TC18 titanium alloy, with low density, high strength and corrosion resistance, is a significant material for the main loadbearingcomponents of aircraft landing gear and other aviation structures. However, its corrosion resistance and wear resistanceare insufficient when it is serviced in the extreme corrosion environments such as sea salt spray and hygrothermal,which greatly affects its wide application. It is significant to design and develop high-quality anti-corrosion and wear resistantcoatings for TC18 titanium alloy. High Velocity Oxygen Fuel (HVOF) spraying WC–12Co is an ideal strengthening methodto replace surface chromium plating. Quantitatively evaluating the influence of spraying process parameters on the coatingquality is the key to prepare high-quality coatings. In this study, a numerical model of HVOF spraying WC–12Co wasestablished with JP5000 spray gun. The spray combustion reaction model and discrete phase model were solved to reveal theevolution characteristics of combustion flame flow and particle flight behavior in the spraying process. Based on the responsesurface method, the optimum spraying process parameters were determined, and the WC–12Co coatings were prepared. Onthis basis, the coating was tested by the SEM, XRD, hardness, friction and wear, salt spray corrosion and seawater corrosion. The corrosion resistance and wear resistance of the WC–12Co coating were comprehensively evaluated. The experimentshows that the WC–12Co coating prepared by HVOF spraying has great performance, which can effectively improve theprotective performance of TC18 substrate.

Fabrication, Structures and Properties of Acrylonitrile/Vinyl Acetate Copolymers and Copolymers Containing Microencapsulated Phase Change Materials

Na Han,Xing-xiang Zhang,Xue-chen Wang,Ning Wang 한국고분자학회 2010 Macromolecular Research Vol.18 No.2

Acrylonitrile(AN)-Vinyl acetate (VAc) copolymers (AN/VAc) were synthesized by redox polymerization and microencapsulated phase change materials (MicroPCMs) were incorporated at the polymerization step. The effect of VAc monomers and/or the MicroPCMs on composition, melting point (Tm), exothermic peak value (Td),average molecular weight (Mη), crystallinity of the copolymers were examined by Fourier Transform Infrared Spectroscopy (FTIR), Elementary Analysis, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TG), Ubbelohde viscosimeter and X-ray Diffraction (XRD). The compositions of the AN/VAc agreed well with the feed ratios. The melting peak shifted to a lower temperature (267 oC) with increasing concentration of VAc monomers and/or MicroPCMs, while the exothermic peak shifted to the higher temperature (324 oC). The average molecular weight of the copolymer was approximately 31,000. The crystallinity of the copolymers decreased with increasing content of VAc monomers and/or MicroPCMs.

The Globle Stability of Non-Linear Systems with Separate Variables

Song Chen Han,Yong De Jin,Wu Xing Jing,Cheng Xun Shao 대한전자공학회 1995 ICEIC:International Conference on Electronics, Inf Vol.1 No.1