Changes in the affordability of 4-year public higher education in China during massification

Shuhua Liu,Enhao Wang,Xuyan Wang 서울대학교 교육연구소 2021 Asia Pacific Education Review Vol.22 No.2

This study investigates how the affordability of 4-year public higher-education tuition in China changed during the massification period. To conduct an in-depth analysis, this paper examines a wide range of data from the National Bureau of Statistics and adopts a series of measurement indicators, including average tuition as a percentage of per-capita GDP, its share in per-capita disposable income and family savings, and its ratio to financial aid. First, this study concludes that during massification, college affordability rapidly declined and then continuously increased. While for a significant majority of Chinese families college tuition is not an unbearable financial burden, it remains expensive for households in the lowest-income quintile. Second, this paper sheds light on the gap in residents’ ability to pay higher-education tuition between urban and rural areas, different regions, and different income groups. It finds a rapid widening in the gap in these dimensions during the early years of massification, which in recent years has gradually narrowed. Indeed, the mode of Chinese higher education has quickly transformed from “high tuition and low aid” to “low tuition and high aid.”

Selective Protection Miniature Circuit Breaker Electromagnetic Actuator Design and Dynamic Optimization

Xianbing Wang,Heyun Lin,Shuhua Fang,Xiangao Wang,Jin Peng 한국자기학회 2019 Journal of Magnetics Vol.24 No.4

This paper first proposes an electromagnetic actuator design and dynamic optimization method for selective miniature circuit breaker (SMCB), and realizes good coordination of electromagnetic actuator force and energy characteristics. Based on short delay tripping mechanism force and magnetic field model, it builds Matlab and Adams co-simulation platform, simulates and analyzes the magnetic field distribution and force energy property under different electromagnetic topological structure, and establishes the permanent magnet electromagnetic structure model. Then, it builds multi-field coupled mathematical model, and studies multi-objective dynamic optimization design for electromagnetic actuator based on quantum particle swarm algorithm. Finally, it develops the 100A miniature circuit breaker. The experimental results show that the optimized electromagnetic actuator design can effectively control the miniature circuit breaker tripping action threshold and mechanical characteristics.

Contact Parameter Computation and Analysis of Air Circuit Breaker with Permanent Magnet Actuator

Shuhua Fang,Heyun Lin,S. L. Ho,Xianbing Wang,Ping Jin,Yunkai Huang,Shiyou Yang 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.

Absolute positioning by multi-wavelength interferometry referenced to the frequency comb of a femtosecond laser.

Wang, Guochao,Jang, Yoon-Soo,Hyun, Sangwon,Chun, Byung Jae,Kang, Hyun Jay,Yan, Shuhua,Kim, Seung-Woo,Kim, Young-Jin Optical Society of America 2015 Optics express Vol.23 No.7

<P>A multi-wavelength interferometer utilizing the frequency comb of a femtosecond laser as the wavelength ruler is tested for its capability of ultra-precision positioning for machine axis control. The interferometer uses four different wavelengths phase-locked to the frequency comb and then determines the absolute position through a multi-channel scheme of detecting interference phases in parallel so as to enable fast, precise and stable measurements continuously over a few meters of axis-travel. Test results show that the proposed interferometer proves itself as a potential candidate of absolute-type position transducer needed for next-generation ultra-precision machine axis control, demonstrating linear errors of less than 61.9 nm in peak-to-valley over a 1-meter travel with an update rate of 100 Hz when compared to an incremental-type He-Ne laser interferometer.</P>

Effect of Y₂O₃ addition on the microstructure and density of AgSnO₂ contact material

Xianhui Wang,Juntao Zou,Shuhua Liang,Zhikang Fan,Peng Xiao 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

AgSnO2-Y2O3 compound powders were prepared by a mechanical alloying (MA) method, AgSnO2-Y2O3 contact material was fabricated by pressing, sintering, repressing and resintering, the effect of Y2O3 addition, repressing and resintering on the microstructure and density of AgSnO2 contact material was investigated. The results show that there are drastic dedensifications or swelling, cracks and pores in AgSnO2 contact material fabricated by powder metallurgy, which thus has a lower density. The addition of Y2O3 is helpful in improving the microstructure and density significantly. The density increases significantly after repressing and resintering, and can reach 8.42 g/cm3. AgSnO2-Y2O3 compound powders were prepared by a mechanical alloying (MA) method, AgSnO2-Y2O3 contact material was fabricated by pressing, sintering, repressing and resintering, the effect of Y2O3 addition, repressing and resintering on the microstructure and density of AgSnO2 contact material was investigated. The results show that there are drastic dedensifications or swelling, cracks and pores in AgSnO2 contact material fabricated by powder metallurgy, which thus has a lower density. The addition of Y2O3 is helpful in improving the microstructure and density significantly. The density increases significantly after repressing and resintering, and can reach 8.42 g/cm3.

Contact Parameter Computation and Analysis of Air Circuit Breaker with Permanent Magnet Actuator

Fang, Shuhua,Lin, Heyun,Ho, S.L.,Wang, Xianbing,Jin, Ping,Huang, Yunkai,Yang, Shiyou The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.

Effect of Stringer Design on the Stability of Stiffened Composite Panel Under In-plane Shear: An Experimental Study

Yuequan Wang,Shuhua Zhu 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.3

The safe exploitation of the buckling and post-bulking region of stiffened composite panels is of prime interest in aerospace engineering. Experiments were carried out to investigate the effects of stringer design on the buckling and post-buckling behavior of stiffened composite panels subjected to in-plane shear loading in this study. Three configurations of I-shape stringers were designed with the same skin in the stiffened composite panels. The shear loading was applied through a customized picture-frame rig which is loaded by a mechanical test machine. Ten specimens in total were manufactured and tested to obtain the buckling loads and the final failure loads, respectively. The experimental results show that the stringer design has much more influence on the buckling load than the final failure load of the stiffened composite panel.

Circ‑NT5C2 stimulates FZD4 expression to promote the malignant progression of osteosarcoma by targeting miR‑488‑3p

Yang Xiaoqi,Wang Shuhua,Zhang Xianjun,Gao Xiangbin,Xu Pengfei 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.5

Background: Circ-NT5C2 has been confirmed to be highly expressed and associated to the progression of osteosarcoma (OS). However, the behind mechanism of circ-NT5C2 involvement in OS remains unclear. Methods: The expression of circ-NT5C2, miR-488-3p and FZD4 was measured by quantitative real-time PCR, and the protein expression of E-cadherin, N-cadherin and FZD4 was detected by western blot. Cell counting kit 8 assay, colony formation assay and 5-ethynyl-2-deoxyuridine assay were performed to assess the cell proliferation. The cell apoptosis was measured by flow cytometry and Caspase3/Caspase9 Activity Assay Kits. Cell migration and invasion were detected by transwell assay. Dual-luciferase reporter assay and RIP assay were carried out to determine the binding relation among circ-NT5C2, miR-488-3p and FZD4. Animal experiment and immunohistochemistry analysis were conducted to explore the role of circ-NT5C2 in tumor growth in vivo. Results: Comparing with controls, the expression of circ-NT5C2 and FZD4 was upregulated and miR-488-3p expression was downregulated in OS tumor tissues and cells. Circ-NT5C2 overexpression facilitated the cell proliferation and motility and induced cell apoptosis of OS cells, whereas circ-NT5C2 knockdown had the opposite effect. Besides, we also found and confirmed that circ-NT5C2 regulated cell malignant behaviors via modulating miR-488-3p/FZD4 axis in OS. Moreover, circ-NT5C2 silencing repressed the growth of xenografts in vivo. Conclusion: Circ-NT5C2 upregulated FZD4 expression via sponging miR-488-3p, thus facilitating cell malignant behaviors in OS.

Epigallocatechin-3-Gallate (EGCG) Attenuates Traumatic Brain Injury by Inhibition of Edema Formation and Oxidative Stress

Zhang, Bo,Wang, Bing,Cao, Shuhua,Wang, Yongqiang The Korean Society of Pharmacology 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.6

Traumatic brain injury (TBI) is a major cause of mortality and long-term disability, which can decrease quality of life. In spite of numerous studies suggesting that Epigallocatechin-3- gallate (EGCG) has been used as a therapeutic agent for a broad range of disorders, the effect of EGCG on TBI remains unknown. In this study, a weight drop model was established to evaluate the therapeutic potential of EGCG on TBI. Rats were administered with 100 mg/kg EGCG or PBS intraperitoneally. At different times following trauma, rats were sacrificed for analysis. It was found that EGCG (100 mg/kg, i.p.) treatment significantly reduced brain water content and vascular permeability at 12, 24, 48, 72 hour after TBI. Real-time PCR results revealed that EGCG inhibited TBI-induced IL-$1{\beta}$ and TNF-${\alpha}$ mRNA expression. Importantly, CD68 mRNA expression decreasing in the brain suggested that EGCG inhibited microglia activation. Western blotting and immunohistochemistry results showed that administering of EGCG significantly inhibited the levels of aquaporin-4 (AQP4) and glial fibrillary acidic protein (GFAP) expression. TBI-induced oxidative stress was remarkably impaired by EGCG treatment, which elevated the activities of SOD and GSH-PX. Conversely, EGCG significantly reduced the contents of MDA after TBI. In addition, EGCG decreased TBI-induced NADPH oxidase activation through inhibition of $p47^{phox}$ translocation from cytoplasm to plasma membrane. These data demonstrate that EGCG treatment may be an effective therapeutic strategy for TBI and the underlying mechanism involves inhibition of oxidative stress.

Identity-Based Key Management Scheme for Smart Grid over Lattice

Wangke Yu,Shuhua Wang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.1

At present, the smart grid has become one of the indispensable infrastructures in people’s lives. As a commonly used communication method, wireless communication is gradually, being widely used in smart grid systems due to its convenient deployment and wide range of serious challenges to security. For the insecurity of the schemes based on large integer factorization and discrete logarithm problem in the quantum environment, an identity-based key management scheme for smart grid over lattice is proposed. To assure the communication security, through constructing intra-cluster and inter-cluster multi-hop routing secure mechanism. The time parameter and identity information are introduced in the relying phase. Through using the symmetric cryptography algorithm to encrypt improve communication efficiency. Through output the authentication information with probability, the protocol makes the private key of the certification body no relation with the distribution of authentication information. Theoretic studies and figures show that the efficiency of keys can be authenticated, so the number of attacks, including masquerade, reply and message manipulation attacks can be resisted. The new scheme can not only increase the security, but also decrease the communication energy consumption.