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Pingxiang Cao,Zhaolong Zhu,Dietrich Buck,Xiaolei Guo,Mats Ekevad,Xiaodong (Alice) Wang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
This study investigates the effect of rake angle on cutting performance during machining of stone-plastic composite material with diamond cutters. To that end, an orthogonal cutting experiment was designed, in which stone-plastic composite material was planed by a polycrystalline diamond (PCD) cutter to produce chips. The features studied include cutting forces, cutting heat, chip formation and cutting quality. The conclusions are as follows: Firstly, increased rake angle causes frictional force and resulting force to decrease, promoting an increase in normal force. Secondly, during planing, cutting heat is primarily distributed in the chips, with less retained in the cutting edge, and the least retained in the machined surface. The temperatures of both cutting edge and chip decline with an increase in rake angle. Thirdly, as rake angle increases, chip morphology changes from segmental to curved and then to particle chips, with chip-breaking lengths first increasing and then decreasing. Finally, an increased rake angle leads a more stable cutting process and improved cutting quality. Therefore, with the precondition of blade strength, a diamond cutter with a larger rake angle can be used to machine stone-plastic composite to improve production quality by forming a smoother machined surface.
( Lan Cao ),( Xiaojie Zhang ),( Xiaolei Wang ),( Chengzhong Zong ),( Jin Kuk Kim ) 한국고무학회 2018 엘라스토머 및 콤포지트 Vol.53 No.3
In this study, in-situ trans-selective polymerization of isoprene was carried out using titanium-based Ziegler- Natta catalysts. The catalysts were prepared by high-energy ball milling. Individually Large-inner-diameter carbon nanotubes (CNTL), and hydroxylated carbon nanotubes (CNTOH), along with magnesium chloride (MgCl<sub>2</sub>) were used as the carriers for the catalysts. The optimum ball-milling time for preparing the CNT/MgCl<sub>2</sub>/TiCl<sub>4</sub> Ziegler-Natta catalysts was 4 h. The CNTOH/MgCl<sub>2</sub>/TiCl<sub>4</sub> catalyst showed a higher efficiency than that of the CNTL/MgCl<sub>2</sub>/TiCl<sub>4</sub> catalyst, based on the rate of polymerization. The effects of the CNT-filler type on the isoprene polymerization behaviors and polymer properties were investigated. The morphologies of the trans-1,4-polyisoprene (TPI)/CNT and TPI/CNTOH nanocomposites exhibited a tube-like shape, and the CNTL and CNTOH fillers were well dispersed in the TPI matrix. In addition, the thermal stability of TPI significantly increased upon the introduction of a small amount of both CNTL/CNTOH fillers (0.15 wt%), owing to the satisfactory dispersion of the CNTL/CNTOH in the TPI matrix.
Preparation of ursodeoxycholic acid by direct electro-reduction of 7-ketolithocholic acid
Xiangxi Yuan,Xuejun Cao,Xiaolei Ma 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.7
A novel method of producing ursodeoxycholic acid was developed through direct electro-reduction of 7-ketolithocholic acid in a divided electrolytic cell. Titanium ruthenium mesh electrode was used as the anode, whilehigh purity lead plate was used as the cathode. The process was optimized with regards to the electrolyte, temperature,concentration of methanol, current density and concentration of anolyte. When potassium bromide was used as theelectrolyte, the saturated solution of 7-ketolithocholic acid in 85-93% (v/v) methanol, current density 9.52-28.6 A/m2and concentration of anolyte at 4-6% (w/w), the maximum percentage yield of ursodeoxycholic acid could be 47%. The method will provide a potential approach for large-scale production of ursodeoxycholic acid.
Zhiqi Huang,Xingyu Li,Tian Xie,Changjiang Gu,Kan Ni,Qingqing Yin,Xiaolei Cao,Chunhui Zhang 대한암학회 2020 Cancer Research and Treatment Vol.52 No.4
Purpose RIOK1 has been proved to play an important role in cancer cell proliferation and migration in various types of cancers—such as colorectal and gastric cancers. However, the expression of RIOK1 in breast cancer (BC) and the relationship between RIOK1 expression and the development of BC are not well characterized. In this study, we assessed the expression of RIOK1 in BC and evaluated the mechanisms underlying its biological function in this disease context. Materials and Methods We used immunohistochemistry, western blot and quantitative real-time polymerase chain reaction to evaluate the expression of RIOK1 in BC patients. Then, knockdown or overexpression of RIOK1 were used to evaluate the effect on BC cells in vitro and in vivo. Finally, we predicted miR-204-5p could be a potential regulator of RIOK1. Results We found that the expression levels of RIOK1 were significantly higher in hormone receptor (HR)–negative BC patients and was associated with tumor grades (p=0.010) and p53 expression (p=0.008) and survival duration (p=0.011). Kaplan-Meier analysis suggested a tendency for the poor prognosis. In vitro, knockdown of RIOK1 could inhibit proliferation, invasion, and induced apoptosis in HR-negative BC cells and inhibited tumorigenesis in vivo, while overexpression of RIOK1 promoted HR-positive tumor progression. MiR-204-5p could regulate RIOK1 expression and be involved in BC progression. Conclusion These findings indicate that RIOK1 expression could be a biomarker of HR-negative BC, and it may serve as an effective prognostic indicator and promote BC progression.