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Korean Studies in China: Based on Chinese-Language Journals 1992-2022
Xuejing Li,Yongbin Xu 한국언어연구학회 2022 언어학연구 Vol.27 No.2
In the 30 years after establishment of diplomatic relations between South Korea and China, Korean studies in China have made substantial, high-level and extensive academic achievements. However, due to reasons such as a language barrier, the mutual communication between Korean studies in China and the world is insufficient. Therefore, in this special time node of 2022, it is necessary to summarize the development history of Korean studies in China and introduce it in English for reference by international researchers engaged in Korean studies. Korean studies in China still have defects such as unbalanced development of ologies, insufficient original research and unclear international positioning. In the future, it is necessary to strengthen the investment in aspects such as ology construction, research quality and international cooperation, so as to improve the existing problems. It is worth mentioning that due to the special relationship between China and North Korea, Chinese researchers are able to play their unique role in the academic dialogue between South Korea and North Korea and internationalization of Korean studies, which is of great significance to the development of Korean studies in the world.
Xuejing Zhang,Chong Ma,Li Wang,Xiaolin Huang,Wei Han,Yubing Gong 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.1
The existing methods for studying the dynamics, thermodynamics and deformation characteristics of screw pumps do not consider the coupling effect of multi field interaction, which deviates from the actual working conditions. Based on SolidWorks and ANSYS software, a three-dimensional finite element model of a lead of conventional single screw pump is established in this paper. The influence of different gas(GVF) volume fraction on the temperature, pressure, deformation, leakage and volumetric efficiency of screw pump was studied by using the fluid-thermal-solid coupling method. The numerical simulation results of volumetric efficiency changing with the inlet and outlet pressure difference under pure liquid condition were verified by the published literature experimental data, and the optimal installation interference value was proposed. The results show that the GVF has an important influence on the comprehensive deformation of the rotor and pump bushing and the volumetric efficiency of the pump; the comprehensive deformation value of the rotor increases gradually from the inlet to the outlet, and increases gradually with the increase of the GVF; with the increase of GVF, the comprehensive deformation value of stator first decreases gradually, and then increases sharply; with the increase of GVF, the leakage first decreases slowly, then increases rapidly, and the volumetric efficiency first increases slowly, then decreases rapidly; the numerical simulation results are in good agreement with the experimental values, and the average deviation is less than 7%.
Xuejing Zhang,Junhu Yang,Wenkai Bei,Wei Han,Canyang Chen,Le Yang 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.2
The efficiency of multiphase twin-screw pump decreases sharply under wet gas conditions (GVF>95%) with severe vibration and thermal problems. Based on the design characteristics of twin-screw pump and screw compressor, a design method of multigradient variable pitch decompression screw pump is to address these problems in this paper. This method keeps the cross section profiles of screw pump unchanged,only changes the pitch of screw. According to the design concept of decompression of screw compressor, the screw rotor is divided into three regions from the inlet to the outlet. The pitch of screw and thread width in these regions are designed separately to increase the volumetric efficiency of the screw pump and reduce the vibration. The effective clearance leakage model of twin-screw pump is simplified and modified. Considering two-phase back flow and combining mechanical model with thermodynamic model, the flow capacity, volumetric efficiency, pressure, and temperature distribution of new and conventional screw pumps are predicted by non-isothermal compression model. The calculations show that the design scheme of multi-gradient variable-pitch decompression screw pump can solve the volumetric efficiency and vibration problems under wet gas conditions fundamentally and can significantly reduce the power consumption of screw pump. However, the problem of temperature rise of screw pump still exists. Cooling system for the screw pump should be designed to continuously cool the screw pump.
On the general decay stability of stochastic differential equations with unbounded delay
Xuejing Meng,Baojian Yin 대한수학회 2012 대한수학회지 Vol.49 No.3
This work focuses on the general decay stability of nonlinear stochastic differential equations with unbounded delay. A Razumikhin-type theorem is rst established to obtain the moment stability but with-out almost sure stability. Then an improved edition is presented to derive not only the moment stability but also the almost sure stability, while ex-isting Razumikhin-type theorems aim at only the moment stability. By virtue of the M-matrix techniques, we further develop the aforementioned Razumikhin-type theorems to be easily implementable. Two examples are given for illustration.
A Domain-independent Dual-image based Robust Reversible Watermarking
Xuejing Guo,Yixiang Fang,Junxiang Wang,Wenchao Zeng,Yi Zhao,Tianzhu Zhang,Shi Yun-Qing 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.12
Robust reversible watermarking has attracted widespread attention in the field of information hiding in recent years. It should not only have robustness against attacks in transmission but also meet the reversibility of distortion-free transmission. According to our best knowledge, the most recent robust reversible watermarking methods adopt a single image as the carrier, which might lead to low efficiency in terms of carrier utilization. To address the issue, a novel dual-image robust reversible watermarking framework is proposed in this paper to effectively utilize the correlation between both carriers (namely dual images) and thus improve the efficiency of carrier utilization. In the dual-image robust reversible watermarking framework, a two-layer robust watermarking mechanism is designed to further improve the algorithm performances, i.e., embedding capacity and robustness. In addition, an optimization model is built to determine the parameters. Finally, the proposed framework is applied in different domains (namely domain-independent), i.e., Slantlet Transform and Singular Value Decomposition domain, and Zernike moments, respectively to demonstrate its effectiveness and generality. Experimental results demonstrate the superiority of the proposed dual-image robust reversible watermarking framework.
Study on the Unsteady Cavitation Flow Characteristics Inside the Mixed Transport Twin Screw Pump
Xuejing Zhang,Li Wang,Guisheng Zhu,Wei Han 한국유체기계학회 2024 International journal of fluid machinery and syste Vol.17 No.1
With the development of screw pumps towards high speed, high pressure, and large flow rate, cavitation in screw pumps has become a phenomenon that cannot be ignored. Based on ANSYS CFX, use SST turbulence model and combine with Rayleigh-Plesset equation to effectively simulate the internal flow of mixed transport twin screw pump, analyze the changes in cavitation morphology and the evolution of cavitation within the entire cycle of the pump, and explore the degree of cavitation on the surface of the screw rotor and the changes in pressure and velocity at the monitoring point with rotation period under different inlet pressures and speeds, and then analyze the changes in cavitation of the twin screw pump under different temperature. The calculation results indicate that cavitation first occurs at the inlet and then gradually penetrates into the interior of the chamber, mainly concentrated in the inlet section and the first chamber. The inlet pressure has a significant impact on cavitation phenomenon. As the inlet pressure decreases, the cavitation intensity continues to strengthen, and the cavitation area also continues to expand. Rotating speed can also affect cavitation, but the effect of speed changes on cavitation is not as significant as that of inlet pressure changes. In addition, increasing the water temperature will also increase the cavitation area. This study reveals the characteristics of cavitation flow in mixed transport twin screw pump, which is of great significance in avoiding cavitation and improving pump performance.
北京市老年人网络养老服务需求意愿及影响因素分析基于 "北京市城市老年人网络养老需求意愿”调查数据
???(Lv Xuejing),丁一(Ding Yi) 글로벌시니어건강증진개발원 2013 글로벌시니어건강증진개발원 논문집 Vol.3 No.1
With the development of the socio-economic and the improving degree of the aging of population, traditional pension service system in the form of family, community and pension agency, which concludes life care, mental health, culture and entertainment, social participation and rights protection has been unable to fully meet increasing needs from the aged either in infrastructure or related services. Under the social environment of rising Internet penetration, the paper studied the status of the network pension service firstly, then analyzed the requirements and influence factors of network pension service of the aged, using survey data of the Beijing demand will of urban elderly Network pension by Binary Logistic regression analysis finally, the paper tried to build a network pension service platform based on the conclusions, which has significance both in theory and practice for improving pension service level and achieving a new leaps