Market Reactions to the Split-share Structure Reform and the Determinants of Compensation: Evidence from Chinese Listed Firms

Li Cheng,Jeng-Ren Chiou,Yenn-Ru Chen,LEEBONGSOO 한국증권학회 2012 Asia-Pacific Journal of Financial Studies Vol.41 No.2

The split-share structure is a unique characteristic of corporate ownership in China, and is often linked to poor firm performance and inefficient corporate governance. In this paper, we investigate market reactions around several important event days during the process of the split-share structure reform (share reform) in Chinese listed firms. The market reacts differently to different events during the process. First, the market reacts positively to firms’ intention of implementing the share reform when the reform prospectus is disclosed and when the compensation is actually paid. Second, after the reform is actually implemented, the market reacts negatively when the expiration date of the lockup agreement is announced, because the restricted trading shares can be freely traded and thus share supply increases after the expiration date. In addition, the compensation paid to tradable shareholders by non-tradable shareholders is determined by the stock liquidity before the reform, the proportion of restricted trading shares, and the type of ultimate shareholders. We further find that the payment of compensation, the proportion of restricted shares after the share reform, and a time gap between suspension and resumption days are the main factors affecting the market reaction.

Reinforcement learning-based control with application to the once-through steam generator system

Li Cheng,Yu Ren,Yu Wenmin,Wang Tianshu 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.10

A reinforcement learning framework is proposed for the control problem of outlet steam pressure of the once-through steam generator(OTSG) in this paper. The double-layer controller using Proximal Policy Optimization(PPO) algorithm is applied in the control structure of the OTSG. The PPO algorithm can train the neural networks continuously according to the process of interaction with the environment and then the trained controller can realize better control for the OTSG. Meanwhile, reinforcement learning has the characteristic of difficult application in real-world objects, this paper proposes an innovative pretraining method to solve this problem. The difficulty in the application of reinforcement learning lies in training. The optimal strategy of each step is summed up through trial and error, and the training cost is very high. In this paper, the LSTM model is adopted as the training environment for pretraining, which saves training time and improves efficiency. The experimental results show that this method can realize the self-adjustment of control parameters under various working conditions, and the control effect has the advantages of small overshoot, fast stabilization speed, and strong adaptive ability.

Built-in potential shift and Schottky-barrier narrowing in organic solar cells with UV-sensitive electron transport layers

Li, Cheng,Credgington, Dan,Ko, Doo-Hyun,Rong, Zhuxia,Wang, Jianpu,Greenham, Neil C. The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.24

<P>The performance of organic solar cells incorporating solution-processed titanium suboxide (TiO<SUB><I>x</I></SUB>) as electron-collecting layers can be improved by UV illumination. We study the mechanism of this improvement using electrical measurements and electroabsorption spectroscopy. We propose a model in which UV illumination modifies the effective work function of the oxide layer through a significant increase in its free electron density. This leads to a dramatic improvement in device power conversion efficiency through several mechanisms – increasing the built-in potential by 0.3 V, increasing the conductivity of the TiO<SUB><I>x</I></SUB> layer and narrowing the interfacial Schottky barrier between the suboxide and the underlying transparent electrode. This work highlights the importance of considering Fermi-level equilibration when designing multi-layer transparent electrodes.</P> <P>Graphic Abstract</P><P>The mechanism by which UV exposure enhances the performance of organic solar cells incorporating TiO<SUB><I>x</I></SUB> layers is investigated by current–voltage and electroabsorption measurements. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp01251h'> </P>

Fault-tolerant control system for once-through steam generator based on reinforcement learning algorithm

Li Cheng,Yu Ren,Yu Wenmin,Wang Tianshu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9

Based on the Deep Q-Network(DQN) algorithm of reinforcement learning, an active fault-tolerance method with incremental action is proposed for the control system with sensor faults of the oncethrough steam generator(OTSG). In this paper, we first establish the OTSG model as the interaction environment for the agent of reinforcement learning. The reinforcement learning agent chooses an action according to the system state obtained by the pressure sensor, the incremental action can gradually approach the optimal strategy for the current fault, and then the agent updates the network by different rewards obtained in the interaction process. In this way, we can transform the active fault tolerant control process of the OTSG to the reinforcement learning agent's decision-making process. The comparison experiments compared with the traditional reinforcement learning algorithm(RL) with fixed strategies show that the active fault-tolerant controller designed in this paper can accurately and rapidly control under sensor faults so that the pressure of the OTSG can be stabilized near the set-point value, and the OTSG can run normally and stably

중국 신장 옌치분지 북부의 허징선상지 지형발달

LI CHENG,황상일,윤순옥 한국지형학회 2023 한국지형학회지 Vol.30 No.4

The Hejing alluvial fan is located on the northern part of the Yanqi Basin and the southern foothills of the southeastern Tianshan Mountains in Xinjiang, China. This study aimed to clarify the process of the fan development by analyzing the sedimentary facies of 18 outcrops in the field. We also examined how tectonic movement influenced the geomorphic development of the fan. According to the sedimentary characteristics of general alluvial fans, it was determined that the Hejing alluvial fan was shaped by fluvial processes and debris flows originating from gravitational action. There were multiple factors affecting the alluvial fans, such as tectonic movement and climate change. The tectonic movement of the Hejing reverse fault-fold zone in front of the southern foothills of the Tianshan Mountains has affected the geomorphic development of the the Hejing alluvial fan. After the Huangshui river eroded the anticline and passed through the water gap, a secondary alluvial fan formed on the southern side of the anticline of the Hejing reverse fault-fold zone. Later, according to the tectonic movement of the fault-fold zone, the Huangshui river moved eastward along the direction of the anticline development. Therefore, the secondary alluvial fans of the Hejing alluvial fan by the Huangshui river developed in sequence.

Size-dependent thermal behaviors of axially traveling nanobeams based on a strain gradient theory

Li, Cheng Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.3

This work is concerned with transverse vibrations of axially traveling nanobeams including strain gradient and thermal effects. The strain gradient elasticity theory and the temperature field are taken into consideration. A new higher-order differential equation of motion is derived from the variational principle and the corresponding higher-order non-classical boundary conditions including simple, clamped, cantilevered supports and their higher-order "offspring" are established. Effects of strain gradient nanoscale parameter, temperature change, shape parameter and axial traction on the natural frequencies are presented and discussed through some numerical examples. It is concluded that the factors mentioned above significantly influence the dynamic behaviors of an axially traveling nanobeam. In particular, the strain gradient effect tends to induce higher vibration frequencies as compared to an axially traveling macro beams based on the classical vibration theory without strain gradient effect.

Analysis and Development of the CFRP Boring Bar for Stability Improvement

Licheng Lu,Can Ni,Gang Liu,Bo Qian,Qinglong An,Zhenzhen Cao,Liqiang Zhang,Junli Li 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

Boring bars with a large length-to-diameter ratio have become increasingly indispensable for deep hole machining. However, the dynamic performance of conventional boring bars may be inadequate, resulting in vibrations. In this paper, a novel boring bar with composites and a constrained layer damping structure was fabricated to suppress vibrations during the boring operation. Initially, the configuration of the CFRP boring bar was proposed based on theoretical analysis, and then the modal parameters were calculated using the bending strain energy method and cantilever beam theory. Subsequently, the geometric design parameters were optimized analytically using the finite element method. Modal and cutting tests were then conducted to evaluate the cutting stability of a CFRP boring bar with a length-to-diameter ratio of 8.4. The modal parameters, vibration signals, and cutting force signals were measured and compared with a carbide boring bar. The experimental results indicated that there was a significant improvement in the cutting stability of the CFRP boring bar.

Fatigue performance monitoring of full-scale PPC beams by using the FBG sensors

Licheng Wang,Jigang Han,Yupu Song 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.13 No.6

When subjected to fatigue loading, the main failure mode of partially prestressed concrete (PPC)structure is the fatigue fracture of tensile reinforcement. Therefore, monitoring and evaluation of the steelstresses/strains in the structure are essential issues for structural design and healthy assessment. The currentstudy experimentally investigates the possibility of using fiber Bragg grating (FBG) sensors to measure thesteel strains in PPC beams in the process of fatigue loading. Six full-scale post-tensioned PPC beams wereexposed to fatigue loading. Within the beams, the FBG and resistance strain gauge (RSG) sensors wereindependently bonded onto the surface of tensile reinforcements. A good agreement was found between therecorded results from the two different sensors. Moreover, FBG sensors show relatively good resistance tofatigue loading compared with RSG sensors, indicating that FBG sensors possess the capability forlong-term health monitoring of the tensile reinforcement in PPC structures. Apart from the above findings, itcan also be found that during the fatigue loading, there is stress redistribution between prestressed andnon-prestressed reinforcements, and the residual strain emerges in the non-prestressed reinforcement. Thisphenomenon can bring about an increase of the steel stress in the non-prestressed reinforcement.

Mesoscale simulation of chloride diffusion in concrete considering the binding capacity and concentration dependence

Licheng Wang,Tamon Ueda 사단법인 한국계산역학회 2011 Computers and Concrete, An International Journal Vol.8 No.2

In the present paper, a numerical simulation method based on mesoscopic composite structure of concrete, the truss network model, is developed to evaluate the diffusivity of concrete in order to account for the microstructure of concrete, the binding effect of chloride ions and the chloride concentration dependence. In the model, concrete is described as a three-phase composite, consisting of mortar, coarse aggregates and the interfacial transition zones (ITZs) between them. The advantage of the current model is that it can easily represent the movement of mass (e.g. water or chloride ions) through ITZs or the potential cracks within concrete. An analytical method to estimate the chloride diffusivity of mortar and ITZ, which are both treated as homogenious materials in the model, is introduced in terms of water-tocement ratio (w/c) and sand volume fraction. Using the newly developed approaches, the effect of cracking of concrete on chloride diffusion is reflected by means of the similar process as that in the test. The results of calculation give close match with experimental observations. Furthermore, with consideration of the binding capacity of chloride ions to cement paste and the concentration dependence for diffusivity, the onedimensional nonlinear diffusion equation is established, as well as its finite difference form in terms of the truss network model. A series of numerical analysises performed on the model find that the chloride diffusion is substantially influenced by the binding capacity and concentration dependence, which is same as that revealed in some experimental investigations. This indicates the necessity to take into account the binding capacity and chloride concentration dependence in the durability analysis and service life prediction of concrete structures.

Mesoscale computational simulation of the mechanical response of reinforced concrete members

Licheng Wang,Jiuwen Bao 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.2

On mesoscopic level, concrete can be treated as a three-phase composite material consisting of mortar, aggregates and interfacial transition zone (ITZ) between mortar and aggregate. A lot of research has confirmed that ITZ plays a crucial role in the mechanical fracture process of concrete. The aim of the present study is to propose a numerical method on mesoscale to analyze the failure mechanism of reinforced concrete (RC) structures under mechanical loading, and then it will help precisely predict the damage or the cracking initiation and propagation of concrete. Concrete is meshed by means of the Rigid Body Spring Model (RBSM) concept, while the reinforcing steel bars are modeled as beam-type elements. Two kinds of RC members, i.e. subjected to uniaxial tension and beams under bending, the fracture process of concrete and the distribution of cracks, as well as the load-deflection relationships are investigated and compared with the available test results. It is found that the numerical results are in good agreement with the experimental observations, indicating that the model can successfully simulate the failure process of the RC members.