Chinese Stock Market Return Predictability: Adaptive Complete Subset Regressions

Keqi Chen,Rui Chen,Xueyong Zhang,Min Zhu 한국증권학회 2016 Asia-Pacific Journal of Financial Studies Vol.45 No.5

This paper proposes a new combination framework to explore the Chinese stock market return predictability. While most well-known predictor variables and simple combinations fail to beat the historical average benchmark, our adaptive complete subset regressions deliver statistically and economically significant out-of-sample performance. The subset, in which each regression includes five predictors, produces a significant R2 OS statistic of 8.00% for January 2006 to September 2014. A mean-variance investor who uses the adaptive subset regressions forecasts, instead of the historical average forecasts, can obtain sizable utility gains of 7.60% per annum. The results of our paper suggest that there is significant predictability in the Chinese aggregate stock market portfolio.

Comparative Study on Three Chinese Versions of James Joyce’s Ulysses with the Guidance of Foreignization and Domestication

Keqi Yao,Yan Liu 한국제임스조이스학회 2023 제임스조이스저널 Vol.29 No.2

At the beginning of the 1980s, some western scholars, like Itamar Even-Zohar, Susan Bassnett, André Lefevere and Lawrence Venuti gradually realized cultural elements in translation studies, such as rewriting, ideology, poetics and patronage, etc. The first Chinese translation was not published until 1994. So far, Jin Di’s edition (1994 and 1996), Xiao Qian/Wen Jieruo’s edition (1994) and Liu Xiangyu’s edition (2021) have been three mainstream translations in China. With the guidance of foreignization and domestication, Jin mainly adopted foreignization, similar to the “Theory of Equivalent Translation” that he has coined. Xiao and Wen claimed that translators should spare no effort to make the translation fluent and colloquial. Liu was devoted to find out the similarity of forms between source language and target language and make detailed interpretation on Irish history and culture. On the premise of respecting the original logic and main ideas, it is the best way to use both foreignization and domestication flexibly if needed. Throughout the centennial journey of “Odysseus” in China, Ulysses and its three Chinese translations have not only embarked on the cross-cultural communication and cooperation between China and Ireland, but also provided a magnificent example to overseas communication of modern Chinese literature in an era of globalization.

Internal Flow Field Measurement of Fluid Machinery Aimed at the Inlet Box with Complex Geometry Using a PDA

W. Keqi,H. Shengli 대한기계학회 1994 KSME/JSME THERMAL and FLUID Engineering Conference Vol.1 No.1

Fixed‑time non‑singular terminal sliding mode control for PMSM drive systems

Huixiang Liu,Keqi Mei,Lu Liu,Yafei Chang,Shihong Ding,Hanzhang Zhang,Jun Wang 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

To further improve the response speed and anti-interference capability of permanent magnet synchronous motors (PMSMs), many advanced control algorithms have been developed. Among the various advanced controls, the fixed-time terminal sliding mode control is one of the effective methods. However, there are still some problems, e.g., too many parameters imposed on the control design in the existing results. In this paper, a fixed-time non-singular terminal sliding mode control (FTNTSMC) method is proposed for the speed loop of a PMSM drive system. First, to improve the closed-loop performance of the PMSM drive system, the relationship between the reference q-axis current and the speed of the PMSM is described in a second-order model. Next, a sliding mode surface with variable exponential coefficients is selected, and the expression of the controller is given. Then, the stability of the PMSM drive system is demonstrated by using Lyapunov functions. Using this method, the fixed-time convergence of the PMSM drive system can be realized and the occurrence of singularity phenomena can be avoided in a simpler and easier method. Finally, the effectiveness of the proposed method is verified by simulation and experimental results.

ZntR positively regulates T6SS4 expression in Yersinia pseudotuberculosis

Tietao Wang,Keqi Chen,Fen Gao,Yiwen Kang,Muhammad Tausif Chaudhry,Zhuo Wang,Yao Wang,Xihui Shen 한국미생물학회 2017 The journal of microbiology Vol.55 No.6

The type VI secretion system (T6SS) is a widespread and versatile protein secretion system found in most Gram- negative bacteria. Studies of T6SS have mainly focused on its role in virulence toward host cells and inter-bacterial inter-actions, but studies have also shown that T6SS4 in Yersinia pseudotuberculosis participates in the acquisition of zinc ions to alleviate the accumulation of hydroxyl radicals induced by multiple stressors. Here, by comparing the gene expression patterns of wild-type and zntR mutant Y. pseudotubercu-losis cells using RNA-seq analysis, T6SS4 and 17 other bio-logical processes were found to be regulated by ZntR. T6SS4 was positively regulated by ZntR in Y. pseudotuberculosis, and further investigation demonstrated that ZntR regulates T6SS4 by directly binding to its promoter region. T6SS4 ex-pression is regulated by zinc via ZntR, which maintains in-tracellular zinc homeostasis and controls the concentration of reactive oxygen species to prevent bacterial death under oxidative stress. This study provides new insights into the regulation of T6SS4 by a zinc-dependent transcriptional regu-lator, and it provides a foundation for further investigation of the mechanism of zinc transport by T6SS.

Electrostatic self‑assembly cellulose nanofibers/MXene/nickel chains for highly stable and efficient seawater evaporation and purification

Shuai Yang,Cai Shi,Keqi Qu,Zhe Sun,Handong Li,Benbin Xu,Zhanhua Huang,Zhanhu Guo 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Seawater evaporation and purification powered by solar energy are considered as a promising approach to alleviate the global freshwater crisis, and the development of photothermal materials with high efficiency is imminent. In this study, cellulose nanofiber (CNF)/MXene/Ni chain (CMN) aerogels were successfully synthesized by electrostatic force and hydrogen bond interaction force. CMN10 achieved a favorable evaporation rate as high as 1.85 kg m? 2 h? 1 in pure water, and the corresponding evaporation efficiency could be up to 96.04%. Even if it is applied to seawater with multiple interference factors, its evaporation rate can still be 1.81 kg m? 2 h? 1. The superior seawater evaporation activity origins from the promoted separation of photoexcited charges and photothermal conversion by the synergy of Ni chain and MXene, as well as the water transport channel supported by the 3D structure frame of CNF. Most importantly, CMN aerogel can maintain water vapor evaporation rates above 1.73 kg m? 2 h? 1 under extreme conditions such as acidic (pH 2) and alkaline (pH 12) conditions. In addition, various major ions, heavy metals and organic pollutants in seawater can be rejected by CMN10 during desalination, and the rejection rates can reach more than 99.69%, ensuring the purity of water resources after treatment. This work shows the great potential of CMN aerogel as a high-efficiency solar evaporator and low-cost photothermal conversion material. Cellulose nanofiber (CNF)/MXene/Ni chain (CMN) aerogels demonstrated high evaporation of water from sea water.

Depth-Resolved Composition and Electronic Structure of Buried Layers and Interfaces in a LaNiO₃/SrTiO₃ Superlattice from Soft- and Hard- X-ray Standing-Wave Angle-Resolved Photoemission

Eiteneer, D.,Palsson, G.K.,Nemsak, S.,Gray, A.X.,Kaiser, A.M.,Son, J.,LeBeau, J.,Conti, G.,Greer, A.A.,Keqi, A.,Rattanachata, A.,Saw, A.Y.,Bostwick, A.,Rotenberg, E.,Gullikson, E.M.,Ueda, S.,Kobayashi Elsevier Scientific Pub. Co 2016 Journal of electron spectroscopy and related pheno Vol.211 No.-

LaNiO<SUB>3</SUB> (LNO) is an intriguing member of the rare-earth nickelates in exhibiting a metal-insulator transition for a critical film thickness of about 4 unit cells [Son et al., Appl. Phys. Lett. 96, 062114 (2010)]; however, such thin films also show a transition to a metallic state in superlattices with SrTiO<SUB>3</SUB> (STO) [Son et al., Appl. Phys. Lett. 97, 202109 (2010)]. In order to better understand this transition, we have studied a strained LNO/STO superlattice with 10 repeats of [4 unit-cell LNO/3 unit-cell STO] grown on an (LaAlO<SUB>3</SUB>)<SUB>0.3</SUB>(Sr<SUB>2</SUB>AlTaO<SUB>6</SUB>)<SUB>0.7</SUB> substrate using soft x-ray standing-wave-excited angle-resolved photoemission (SWARPES), together with soft- and hard- x-ray photoemission measurements of core levels and densities-of-states valence spectra. The experimental results are compared with state-of-the-art density functional theory (DFT) calculations of band structures and densities of states. Using core-level rocking curves and x-ray optical modeling to assess the position of the standing wave, SWARPES measurements are carried out for various incidence angles and used to determine interface-specific changes in momentum-resolved electronic structure. We further show that the momentum-resolved behavior of the Ni 3d e<SUB>g</SUB> and t<SUB>2g</SUB> states near the Fermi level, as well as those at the bottom of the valence bands, is very similar to recently published SWARPES results for a related La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>MnO<SUB>3</SUB>/SrTiO<SUB>3</SUB> superlattice that was studied using the same technique (Gray et al., Europhysics Letters 104, 17004 (2013)), which further validates this experimental approach and our conclusions. Our conclusions are also supported in several ways by comparison to DFT calculations for the parent materials and the superlattice, including layer-resolved density-of-states results.