Positive Return–Volatility Correlation and Short Sale Constraints: Evidence from the Chinese Market

Zhiming Fu,Liang Wu,Hong Luo 한국증권학회 2018 Asia-Pacific Journal of Financial Studies Vol.47 No.1

The market price is a convex function of information when short sales are constrained. Borrowing constraints limit investors to bidding up the price. The two effects imply an asymmetric return–volatility correlation (RVC) when information shifts. We build a model to show that: (i) short selling decreases RVC, while margin trading increases RVC; (ii) RVC increases with disagreement; and (iii) RVC increases with returns. The Chinese stock market is ideal for the empirical test because only certain stocks are eligible for short selling and margin trading in the slow policy adoption process. We obtain evidence to support the theoretical predictions correlation.

Influence of heterogeneous mechanical properties on the performance of forward static bending test of rail welded joint

Pingpo Fu,Zhiming Zhu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

The contact FE model for forward static bending test of the rail joint welded by narrow gap arc welding (NGAW) was established, in which the welded joint with heterogeneous mechanical properties was divided into multiple regions with gradual and step-changed mechanical properties determined according to the hardness distribution characteristics of the actual rail welded joint. Then the stress and strain distribution of the heterogeneous rail welded joint was calculated and analyzed under the forward static bending load, referring to the standard of static bending test for the rail joint welded by flash butt welding. The calculated results indicate that the magnitude of equivalent stress (Von Mises stress) presents positive correlation with the value of strength in the rail welded joint, while the failure tendency presents negative correlation with the value of strength, and the lowest strength region in HAZ is the weakest and most vulnerable part of the rail welded joint. Therefore, increasing the strength of soften zone in HAZ by appropriate post-weld heat treatment process is effective to improve the performance of forward static bending test. Further analysis was made by adjusting the value of strength in the weld zone within the heterogeneous rail welded joint, and it was found that the weld zone with high strength match could reduce the value of Von Mises stress of all other zones and improve the performance of forward static bending test of the rail welded joint. All these researches are expected to provide valuable reference and guidance for the adjustment and optimization of the process of NGAW and post-weld heat treatment, and the improvement of the performance of static bending test of rail welded joint.

Comparative Hot Workability Characteristics of an Al–Si/SiCp Aluminium Matrix Composite Hybrid Reinforced with Various TiB2 Additions

Xinrong Chen,Zhiming Xu,Dingfa Fu,Hui Zhang,Jie Teng,Fulin Jiang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6

Hot compression tests were conducted on Al–Si/SiCp + TiB2 hybrid aluminium matrix composites with various TiB2contentsat temperatures from 350 to 500 °C and strain rates from 0.001 to 1 s−1. The hot workability characteristics and deformationmechanisms were investigated by combining constitutive equations, processing maps and microstructural observationsthrough scanning electron microscopy and transmission electron microscopy measurements. The results showed that therewere small differences in the peak stresses when the contents of TiB2were 3% and 5%, while the peak stress increased whenthe content of TiB2reached 8%. The contents of TiB2had little influence on the activation energy but affected the processingmaps to a certain extent. The areas of the instability zones were observed to gradually increase with increased TiB2additions. The optimal deformation conditions of the studied materials migrated from a low temperature and high strain rate to a hightemperature and low strain rate with increasing TiB2content. In addition, the flow softening mechanism transformed fromdynamic recrystallization + dynamic recovery to dynamic recovery with increasing TiB2content.

Study on Matching between Cultivation of Person with Ability of Major in Urban Management and Social Need

Wu Bo,Fu Zhiming,Ge Xiyan 한국도시행정학회 2013 한국도시행정학회 학술발표대회 논문집 Vol.2013 No.9

Long non-coding RNA RP11-6O2.4 indicates poor prognosis and suppresses cell cycle progression through the p38-MAPK signaling pathway in gastric cancer

Yang Feng,Zhiming Fu,Yajun Luo,Wang Tan,Zilin Liu,Pengcheng Ye,Fei Lu,Wanping Xiang,Linghan Tang,Lin Yao,Mengyun Song,Qingmei Huang,Yilun Liu,Jiangwei Xiao 대한독성 유전단백체 학회 2019 Molecular & cellular toxicology Vol.15 No.3

Backgrounds: The role of long non-coding RNAs (lncRNA) in gastric cancer (GC) has been highlighted in studies conducted over the past decade. However, the potential clinical value and the mechanisms of action of RP11-6O2.4 in GC have not been thoroughly elucidated to date. The specific aim of the present study was to assess RP11-6O2.4 and to explore its role in human GC. Methods: Quantitative real-time polymerase chain reaction (qPCR) was performed to analyze the expression levels of RP11-6O2.4 in GC tissues, paired adjacent noncancerous tissues (ANTs) and GC cell lines. In addition, the correlation between RP11-6O2.4 expression and the clinical characteristics and prognosis of patients with GC was statistically analyzed. The effects of RP11- 6O2.4 on the GC cell cycle transformation through the p38-MAPK signaling pathway were explored by flow cytometry, qPCR and Western blot analysis after treatment with SB203580, a p38MAPK specific inhibitor, in vitro. Results: The expression levels of RP11-6O2.4 in GC tissues were significantly lower than the paired ANTs (P<0.05). In addition, RP11-6O2.4 expression was significantly lower in cases with older age, longer maximum tumor diameter, higher ASA grade and deeper invasive depth (P<0.05). RP11-6O2.4 expression was significantly higher in cases with well/middle differentiation than poor/no differentiation; higher in cases without lymph node metastasis than in lymph node metastasis; and higher in cases in stage Ⅰ/Ⅱ than in stage Ⅲ/Ⅳ. An in vitro assay showed that RP11-6O2.4 induced G0/ G1 phase cell cycle arrest, likely by regulating the p38- MAPK signaling pathway. Conclusion: The above mentioned data suggested that RP11-6O2.4 was a tumor-suppressor gene in GC. RP11- 6O2.4 might play an important role in the cell cycle transformation by regulating the p38-MAPK signaling pathway, thereby representing a specific biomarker and a potential molecular target for the treatment of GC.

Synergistic protective effect of a BN-carbon separator for highly stable lithium sulfur batteries

Kim, Patrick Joo Hyun,Seo, Jihoon,Fu, Kun,Choi, Junghyun,Liu, Zhiming,Kwon, Jiseok,Hu, Liangbing,Paik, Ungyu Nature Publishing Group 2017 NPG Asia Materials Vol.9 No.-

<P>Lithium sulfur (Li-S) batteries have drawn much attention as next-generation batteries because of their high theoretical capacity (1672 mAh g(-1)), environmental friendliness and low cost. However, several critical issues, which are mainly associated with the polysulfide shuttling effect, result in their poor electrochemical performance. Carbon-modified separators have been introduced to attempt to address these systemic challenges. However, this approach focused only on the suppression of dissolved polysulfides on the cathodic side without considering the further entrapment of polysulfides on the anodic side. In this study, we first designed a multifunctional trilayer membrane comprising a carbon layer and a boron nitride (BN) layer to facilitate the electrochemical performance of Li-S batteries and protect the Li anode from unexpected side reactions. When a BN-carbon separator was employed, the sulfur cathode delivered stable capacity retention over 250 cycles and an excellent specific capacity (702 mAh g(-1)) at a high current density (4 C). The BN-carbon separator also facilitated the uniform plating/striping of Li and, thus, suppressed the severe growth of dendritic Li on the electrode; this led to the stable operation of the Li anode with a high Coulombic efficiency and improved cycling performance.</P>