호텔 종사원의 성취목표지향성과 경력몰입의 관계에서 자기주도 학습능력의 매개효과

( Xiaogang Liu ),최우성 ( Woosung Choi ),왕용 ( Long Wang ) 관광경영학회 2018 관광경영연구 Vol.82 No.-

Achievement goal orientation and self-directed learning ability are important factors in efficient human resource management. As such, this study sought to empirically review what is the achievement goal orientation that affects career commitment of hotel employees, and how self-directed learning ability has a mediating effect on career commitment. Employees of five star, four star hotels in Seoul, area were used as subjects. Self-directed learning ability had a partially mediating effect on achievement goal orientation and career commitment. Self-directed learning ability had a partially mediating effect on achievement goal orientation and career commitment. Self-directed learning ability had a complete mediating effect on skilled approach and execution avoidance, as well as on career commitment, while self-directed learning ability had a partially mediating effect on execution approach and career commitment. Self-directed learning ability did not have a mediating effect on avoidance of mastry of skills and career commitment. The implications of these findings are as follows. A culture where learning motivation, efforts and improvement of individual competence are more strongly emphasized was correlated with a higher career commitment of employees. Achievement goal orientation occurs when a person’s goal is clear and the individual has a high interest in his task. Therefore, hotel corporations must ensure that their employees can clearly set their goals within the organization and take higher interest in them. Hotel corporations need to create an environment that helps promote self-directed learning ability of employees.

Cyclic Behavior of Q345GJ Steel Used in Energy Dissipation Shear Links

Xiaogang Liu,Yufei Liu 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

The cyclic behavior of Q345GJ steel was explored by strain cycle tests, stress cycle tests and uniaxial tension tests. The results of strain cycle tests confirmed that Q345GJ steel has no cyclic hardening, and it had rare strain amplitude effect or strain history effect. The stress cycle tests confirmed that the cumulative plastic strain goes up stably under eccentric stress with increasing loading loops. Thus, it can be concluded that the hardening characteristics of Q345GJ coincide with kinematic hardening, having almost no isotropic hardening. The superposition of four nonlinear kinematic hardening model based on Chaboche’s constitutive model was used to predict the hardening characteristics of Q345GJ steel, and the parameters of the constitutive model were calibrated based on the test results. The numerical validation of the constitutive model confirmed that the proposed parameters can give good simulation for strain cycle behavior and stress cycle behavior of Q345GJ steel.

Psoralen synergies with zinc implants to promote bone repair by regulating ZIP4 in rats with bone defect

Meijing Liu,Junlong Tan,Shuang Li,Chaoyang Sun,Xiangning Liu,Hongtao Yang,Xiaogang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background The regulation of dose-dependent biological effects induced by biodegradation is a challenge for the production of biodegradable bone-substitute materials, especially biodegradable zinc (Zn) -based materials. Cytotoxicity caused by excess local Zn ions (Zn2+) from degradation is one of the factors limiting the wide application of Zn implants. Given that previous studies have revealed that delayed degradation of Zn materials by surface modification does not reduce cytotoxicity; in the present study, we explore whether preventing the entry of excess Zn2+ into cells may can reduce local Zn toxicity by applying Psoralen (PRL) to Zn implants and assessing its ability to regulate intracellular Zn2+ concentrations. Methods The effects of different concentrations of Zn2+ on cellular activity and cytotoxicity were investigated; briefly, we identified natural compounds that regulate Zn transporters, thereby regulating the concentrations of intracellular Zn2+, and applied them to Zn materials. Of these materials, PRL, a natural, tricyclic, coumarin-like aromatic compound that promotes the proliferation and differentiation of osteoblasts and enhances osteogenic activity, was loaded onto the surface of a Zn material using peptides and chitosan (CS), and the surface characteristics, electrochemical properties, and activity of the modified Zn material were evaluated. In addition, the ability of Zn + CS/pPRL implants to promote bone formation and accelerate large-scale bone defect repairs was assessed both in vitro and in vivo. Results We determined that 180 μM Zn2+ significantly induced pre-osteoblast cytotoxicity, and a 23-fold increase in Zrt- and Irt-like protein 4 (ZIP4) expression. We also found that PRL dynamically regulates the expression of ZIP4 in response to Zn2+ concentration. To address the problem of cytotoxicity caused by excessive Zn2+ in local Zn implants, PRL was loaded onto the surface of Zn implants in vivo using peptides and CS, which dynamically regulated ZIP4 levels, maintained the balance of intracellular Zn2+ concentrations, and enhanced the osteogenic activity of Zn implants. Conclusions This study reveals the importance of Zn2+ concentration when using Zn materials to promote bone formation and introduces a natural active ingredient, PRL, that can regulate intracellular Zn2+ levels, and thus may be clinically applicable to Zn implants for the treatment of critical bone defects.

A Systematic Study on the Relationship Between Viscosity Sensitivity and Temperature Dependency of BODIPY Rotors

Xiao Liu,Weijie Chi,Antonio de J Gómez-Infante,Eduardo Peña-Cabrera,Xiaogang Liu,Young-Tae Chang 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.1

Different functions of molecular rotors based on viscosity sensitivity and temperature dependence.

A cosmic ray muons tomography system with triangular bar plastic scintillator detectors and improved 3d image reconstruction algorithm: A simulation study

Zhao Yanwei,Luo Xujia,Qin Kemian,Liu Guorui,Chen Daiyuan,Augusto R.S.,Zhang Weixiong,Luo Xiaogang,Liu Chunxian,Liu Juntao,Liu Zhiyi 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

Purpose: Muons are characterized by a strong penetrating ability and can travel through thousands of meters of rock, making them ideal to image large volumes and substances typically impenetrable to, for example, electrons and photons. The feasibility of 3D image reconstruction and material identification based on a cosmic ray muons tomography (MT) system with triangular bar plastic scintillator detectors has been verified in this paper. Our prototype shows potential application value and the authors wish to apply this prototype system to 3D imaging. In addition, an MT experiment with the same detector system is also in progress. Methods: A simulation based on GEANT4 was developed to study cosmic ray muons' physical processes and motion trails. The yield and transportation of optical photons scintillated in each triangular bar of the detector system were reproduced. An image reconstruction algorithm and correction method based on muon scattering, which differs from the conventional PoCA algorithm, has been developed based on simulation data and verified by experimental data. Results: According to the simulation result, the detector system’s position resolution is below 1 ~ mm in simulation and 2 mm in the experiment. A relatively legible 3D image of lead bricks in size of 20 cm 5 cm 10 cm used our inversion algorithm can be presented below 1 104 effective events, which takes 16 h of acquisition time experimentally. Conclusion: The proposed method is a potential candidate to monitor the cosmic ray MT accurately. Monte Carlo simulations have been performed to discuss the application of the detector and the simulation results have indicated that the detector can be used in cosmic ray MT. The cosmic ray MT experiment is currently underway. Furthermore, the proposal also has the potential to scan the earth, buildings, and other structures of interest including for instance computerized imaging in an archaeological framework.

Three-Dimensional Porous Carbon Nanotube Papers as Current Collector and Buffer for SnO2 Anodes

Xiaogang Sun,Zhiwen Qiu,Long Chen,Manyuan Cai,Jie Wang,Xu Li,Wei Chen,Zhenhong Liu,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.11

A novel three-dimensional porous conductive papers have been successfully synthesized via a simple physical route. Multi-walled carbon nanotubes (MWCNTs)@SnO2 composite anode materials are embedded in porous conductive papers. The peculiar structure can accommodate the huge volume expansion of MWCNTs@SnO2 composite anode materials during charge–discharge process. The framework formed by MWCNTs and cellulose can greatly improve the strength, stability and flexibility of the electrode. In addition, the structure successfully prevent the aggregation of SnO2 nanoparticles and collapse of MWCNTs@SnO2 composite electrode, leading to the improvement in electrochemical utilization and stable cyclability. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The electrochemical properties and application were evaluated by galvanostatic discharge–charge testing and cycling voltammetry. As a result, the MWCNTs@SnO2 composite electrode showed excellent rate performance. The discharge capacity remains about 680mAh g -1 after 100 cycles at 200mA g -1, and even around 300mAh g -1 at 1000mA g -1.

MgO nanosheets with N-doped carbon coating for the efficient visible-light photocatalysis

Xiaogang Zheng,Ke Wang,Zhiping Huang,Yong Liu,Jing Wen,Hao Peng 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

MgO nanosheets with N-doped carbon coating (MgO@N-C) were fabricated for the enhancedphotocatalytic degradation of dyes (methylene blue, methyl violet, and Rhodamine B) and antibiotics(ciprofloxacin and tetracycline hydrochloride) in visible light region. The effects of N-doping content,reactant concentration, pH value, and inorganic ions on the photocatalytic performance in degradation ofmethylene blue were investigated in this work. Narrow band gap energy and heterojunction interfaceendowed the extended light-harvesting capacity to visible light region and the efficient charge transfer,leading to the excellent photocatalytic activity and durability of MgO@N-C-3 with N-doping content of 1.52%.

Carbon-coated Mg–Al layered double oxide nanosheets with enhanced removal of hexavalent chromium

Xiaogang Zheng,Fuyan Kang,Xinhui Liu,Hao Peng,JinYang Zhang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

Carbon-coated Mg–Al layered double oxide (MgAl@C LDO) nanosheets were synthesized for the removalof hexavalent chromium (Cr(VI)) ions. Carbon coating could enhance the sorption capacity of Mg5Al1 LDOfor the Cr(VI) removal. The sorption capacity of Mg5Al1@C LDO increased and then decreased with anincrease in carbon-coated content, of which the Mg5Al1@C-2 with a carbon thickness of around 5.0 nmexhibited the best sorption capacity. The sorption behaviors of Mg5Al1@C-2 was explained by Langmuirsorption model, pseudo-second-order model, Weber–Morris model, and Boyd kinetic model. Mg5Al1@C-2 for Cr(VI) removal was a spontaneous, endothermic, and chemisorption process.

Switched‑capacitor‑based high‑gain DC–DC converter for fuel cell vehicle powertrain

Xiaogang Wu,Jiulong Wang,Yun Zhang,Zhengxin Liu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

A novel DC–DC converter with switched capacitor is proposed to satisfy the requirements of fuel cell vehicles for DC–DC converter in terms of step-up ratio, efficiency, and voltage stress. The proposed converter has the advantages of high step-up ratio, low voltage stress of each device, the common ground, high efficiency, and small size. It is compared with other converters in the above aspects. The dynamic model of the proposed converter can be obtained on the basis of the small-signal modeling method and the state space average method. Experimental results show that the proposed converter has a high step-up ratio under a nonextreme duty cycle state, and the highest efficiency is 94.25%. Compared with the dual-switch boost converter, the proposed converter has certain advantages in terms of step-up ratio, component voltage stress, and efficiency. Consequently, it is more suitable for the powertrain of fuel cell vehicles.

Preparation of novel Ce (IV)-based MOF/GO composite and its highly effective phosphate removal from aqueous solution

Xiaogang Han,Zhuannian Liu,Mohammad Fahim Bakhtari,Junnan Luo,Luncong Deng 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.6