Effect of Initial Microstructure on the Hot Deformation Behavior and Microstructure Evolution of Aluminum Alloy AA2060

Chaoyang Li,Guangjie Huang,Lingfei Cao,Ruoxi Zhang,Yu Cao,Bin Liao,Lin Lin 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The microstructure evolution and hot deformation behavior of a Li-containing aluminum alloy AA2060 with different initialmicrostructure (homogenized vs. pre-rolled) were studied by isothermal hot deformation. The tests were performed within awide range of deformation temperatures of 370–490 ℃ and strain rates of 0.01–10 s−1. Results show that the stress drop ratioof the pre-rolled specimen is higher than that of the homogenized one under the same deformation condition. Microstructurewere analyzed on the thermal processing maps in unstable and optimum processing domain, and a higher dynamic recrystallizationfraction can be observed in the pre-rolled specimen that has more substructures and smaller grains. Four typesof the dynamic recrystallization were observed and the mechanism for deformation softening was discussed in this work.

Research on the Effect of Technostress on Addiction Tendency according to Smart Device Properties-Digital Detox as a Controlling Variable

Li Chaoyang,Xie Jinkai 아시아사회과학학회 2021 Jornal of Asia Social Science Vol.4 No.3

정보통신기술은 빠른 속도로 발전함에 따라 스마트폰을 비롯한 기기는 휴대 편리하고 업무의 효율성이 높아지고 많은 편리함을 가져올 수 있다. 그렇지만 과도하게 사용하면 부정적 영향인 테크노스트레스를 유발시키고 이런 부정적인 문제를 해결하는 것은 화제가 될 것이다. 본 연구는 스마트폰 속성인 기술적 한계, 복잡성, 변화의 속도는 테크노스트레스에 미치는 영향을 분석한다. 그 다음으로 테크노스트레스는 중독경향에 미치는 영향을 분석한다. 마지막으로 디지털 디톡스의 조절효과를 검증한다. 본 연구를 위해 중국인을 대상으로 설문조사를 실시하였다. 총 212 부 설문지를 배포하였으며 미 회수된 설문지와 불성실하게 답변한 설문지를 제외한 총 202 부를 분석하였다. SPSS23 프로그램을 통해 신뢰성과 타당성을 확인하였으며 회귀분석을 이용하여 가설을 검증하였다. 가설 검증 결과, 첫째, 독립변수인 기술적 한계와 변화의 속도가 테크노스트레스에 정(+)의 영향을 미치는 것으로 검증하였지만 복잡성은 테크노스트레스에 유의미한 영향을 미치지 않는 것을 검증하였다. 둘째, 테크노스트레스는 중독경향에 정(+)의 영향을 미치는 것을 검증하였다. 셋째, 디지털 디톡스는 조절효과가 없는것으로 나타났다. 위와 같은 결과를 바탕으로 스마트기기 속성이 테크노스트레스와의 관계의 이론적 실무적 시사점을 살펴보았다. As information and communication technology develops rapidly, devices such as smartphones are convenient to carry, work efficiency is increased, and many conveniences can be brought. However, excessive use will cause technostress, which is a negative effect, and solving these negative problems will be a hot topic. This study analyzes the effects of smartphone attributes such as technical limitations, complexity, and speed of change on technostress. Next, we analyze the effect of technostress on addiction tendency. Finally, the moderating effect of digital detox is verified. For this study, a survey was conducted on Chinese people. A total of 212 copies of the questionnaire were distributed, and a total of 202 copies were analyzed, excluding unrecovered and unfaithfully answered questionnaires. Reliability and validity were confirmed through the SPSS23 program, and the hypothesis was verified using regression analysis. As a result of hypothesis verification, first, it was verified that the independent variables, technical limitations and speed of change, had a positive (+) effect on technostress, but complexity did not have a significant effect on technostress. Second, it was verified that technostress has a positive (+) effect on addiction tendency. Third, digital detox was found to have no moderating effect. Based on the above results, the theoretical and practical implications of the relationship between smart device attributes and technostress were examined.

Design and investigation of a cycloid helical gear drive

Xuan Li,Chaoyang Li,Bingkui Chen,Dong Liang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9

In this paper, an original analysis of the geometric design of a parallel-axis cycloid helical gear drive and an investigation on its basic meshing characteristics are presented. This type of gear drive consists of a pinion with one tooth and a cycloid-helix gear in continuous line contact along the whole length of the tooth. Firstly, mathematical formulations of their tooth surfaces are derived based on the envelope theory and homogeneous coordinate transformation. Secondly, the undercutting analysis is applied to determine the design constraint to avoid the undercutting on the cycloid-helix gear tooth surface. Then, the meshing characteristics including the contact lines, surface of action, induced normal curvature are analyzed. Numerical example is presented to demonstrate the influence of design parameters on the contact stress distribution. Finally, the loaded tooth contact analysis is performed to simulate the tooth contact condition and to validate the stress distribution by the finite element method.

Representation of Volume Change for Bentonite in Saline Solution based on Modified Effective Stress

Xiaoyue Li,Chaoyang Li,Yongfu Xu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5

Bentonite is usually selected as the buffering barrier material for high-level nuclear waste repository due to its characteristics of high expansibility and low permeability, yet the swelling properties are influenced by the saline solution existing in the fissures of surrounding rocks. Quantifying the effects of saline solution concentration on the swelling property of compacted bentonite is significant for assessing the security of engineering barrier used to dispose high-level radioactive waste. In this study, the modified effective stress incorporating with osmotic suction generated from saline solution is proposed to depict the volume changes for bentonite in saline solution with different concentrations by a unique equation. The osmotic suctions are calculated with the simplified Debye-Hückel equation and the results are validated by comparing with the experimental data in other literatures. The published experimental data prove the uniform relationship between the volume change and the modified effective stress in saline solution with different concentrations. Therefore, the quantitative predictions of volume change of bentonite in saline solution with different concentrations are presented using the modified effective stress concept.

银发一族智慧社区养老服务参与意愿影响因素研究

李超阳(Chaoyang Li),牛凯宁(Kaining Niu),任玉璐(Yulu Ren),梁洁(Jie Liang),曹露浩(Luhao Cao) YIXIN 출판사 2024 Journal of China Studies Vol.2 No.3

随着全球人口老龄化速度日益加快,解决养老问题成为一大难题,基于大数据及互联网技术的智慧社区养老服务应运而生。为进一步探析老年人对于智慧社区养老服务参与意愿的影响因素,首先通过从智慧社区养老和参与意愿两个方面梳理相关文献研究,为本文提供理论依据;其次,为实现研究的典型性,以潍坊市作为研究试验点,通过发放问卷的方式收集关于老年人智慧社区养老服务参与意愿的调研并采用单因素分析进行因素筛查,将筛查后的结果通过二元logistic 回归方法进行分析;再次,得出结果主要从三个方面分析,个体因素中年龄、户口类型、职业;家庭内部因素中居住状况、家人是否支持您参加社区养老以及外部因素中邻里关系、暴露隐私是老年人对智慧社区养老的参与意愿的影响因素;最后,通过讨论发现现存问题所在并提出通过提供以需求为导向的智慧社区养老服务、更新养老观念、营造良好外部环境等举措来提高老年人智慧社区养老参与意愿。 With the accelerating global aging population, solving eldercare issues has become a significant challenge, and smart community elderly care services based on big data and internet technology have emerged as a response. To further analyze the factors influencing the elderly’s willingness to participate in smart community elderly care services, this study first reviews relevant literature from the perspectives of smart community elderly care and willingness to participate, providing a theoretical basis for this paper. Next, to ensure the typicality of the research, Weifang City is selected as the study’s experimental site. Questionnaires were distributed to collect data on the elderly’s willingness to participate in smart community elderly care services, and univariate analysis was conducted for factor screening. The screened results were then analyzed using binary logistic regression. The results are mainly analyzed from three aspects: individual factors such as age, type of household registration, and occupation; family internal factors such as living situation, family support for participating in community elderly care, and external factors such as neighborhood relationships and exposure to privacy. These factors influence the elderly’s willingness to participate in smart community elderly care. Finally, through discussion, the study identifies existing problems and proposes measures to improve the elderly’s willingness to participate in smart community elderly care, such as providing demand-oriented services, updating elderly care concepts, and creating a favorable external environment.

Quantum Authentication Protocol of Classical Messages Based on Different Sets of Orthogonal Quantum States

Xiangjun,Chaoyang Li,Dongsheng Chen,Fagen Li 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.5

Most of the quantum authentication protocols are used to authenticate quantum messages. In this paper, by using a pair of non-entangled qubits, a quantum authentication protocol of classical messages is proposed. In the pair of qubits, the first one is used to carry a bit message, and the second one is used as a tag to authenticate the classical message. In our protocol, a bit string instead of a sequence of maximally entangled states is used directly as an authentication key, so the authentication key can be easily stored offline. On the other hand, in our protocol, a unitary operation UA is chosen to encrypt the qubits so that the successful probability of all attacks analyzed is less than one. Our quantum authentication protocol is secure against various attacks such as the no-message attack and message attacks.

도시 노인 요양산업 투자에 관한 분석과 연구 - 타이강 커뮤티티 사례를 중심으로

Mingjun Lei,Chaoyang Li 한국경영실무학회 2023 한국경영실무학회 학술발표대회 Vol.2023 No.12

Rotate vector reducer design using resnet-based model and integration of discretized optimization

Jiacheng Miao,Chaoyang Li,Xing Du,Bingkui Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4

The author present an artificial intelligent (AI)-based deep generative model that demonstrate how to generate design options of mechanical systems, which are not only suitable for specific working conditions but also optimized for engineering performance. In current study, (1) a structural generative residual netowork (SG-Resnet) model is developed to establish the non-linear mapping between the working conditions and the external dimensions of the reducer, the main hyperparameters influencing the prediction ability and learning rate of the SG-Resnet are analyzed. (2) The mixed population non dominated sorting genetic algorithm-II (MP-NSGA-II) is proposed, and used to obtain pareto optimal solutions of the internal dimensions of the reducer. Experiments are performed to validate the positive effect of the structural generative model on the stiffness of the reducer. This research provides a novel method for reducer design and lays a solid foundation for the development of sequential engineering software for integrated rotate vector (RV) reducer.

On the Security of a Group Key Agreement Protocol and Its Improvement with Pairings

Xiangjun Xin,Chaoyang Li,Dongsheng Chen,Fagen Li 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.2

In the paper, we analyze the security vulnerability of the key agreement protocol proposed by Lee et al.'s. We present a forgery attack to their protocol. In this attack, the adversary can modify the signed message and forge a new signature, which can pass the verification. Then, we propose a new group key agreement protocol, which overcomes this security drawback. The new protocol can be proved to be secure under Elliptic Curve Discrete Logarithm Problem, Bilinear Computational Diffie–Hellman Problem and Square-Exponent Problem. On the other hand, in the new protocol, only three pairing operations are used, so it is more efficient. Our protocol is also a contributory group key agreement protocol.

Mangiferin ameliorates cardiac fibrosis in D-galactose-induced aging rats by inhibiting TGF-β/p38/MK2 signaling pathway

Jing Cheng,Chaoyang Ren,Renli Cheng,Yunning Li,Ping Liu,Wei Wang,Li Liu 대한약리학회 2021 The Korean Journal of Physiology & Pharmacology Vol.25 No.3