ON THE NONLINEAR MATRIX EQUATION $X+\sum_{i=1}^{m}A_i^*X^{-q}A_i=Q$(0<q≤1)

Yin, Xiaoyan,Wen, Ruiping,Fang, Liang Korean Mathematical Society 2014 대한수학회보 Vol.51 No.3

In this paper, the nonlinear matrix equation $$X+\sum_{i=1}^{m}A_i^*X^{-q}A_i=Q(0<q{\leq}1)$$ is investigated. Some necessary conditions and sufficient conditions for the existence of positive definite solutions for the matrix equation are derived. Two iterative methods for the maximal positive definite solution are proposed. A perturbation estimate and an explicit expression for the condition number of the maximal positive definite solution are obtained. The theoretical results are illustrated by numerical examples.

ON THE NONLINEAR MATRIX EQUATION X + ∑m i=1 A iX−qAi = Q(0 < q 1)

Xiaoyan Yin,Ruiping Wen,Liang Fang 대한수학회 2014 대한수학회보 Vol.51 No.3

In this paper, the nonlinear matrix equation X + m ∑ i=1 A∗ i X−qAi = Q (0 < q 1) is investigated. Some necessary conditions and sufficient conditions for the existence of positive definite solutions for the matrix equation are derived. Two iterative methods for the maximal positive definite solution are proposed. A perturbation estimate and an explicit expression for the condition number of the maximal positive definite solution are obtained. The theoretical results are illustrated by numerical examples.

Measurement and Influencing Factors of Organizational Justice Perception

Yin, Xiaoyan 한중경제문화학회 2015 한중경제문화연구 Vol.5 No.-

Effect of Precipitate State on Mechanical Properties, Corrosion Behavior, and Microstructures of Al–Zn–Mg–Cu Alloy

Xiaoyan Peng,Yao Li,Guofu Xu,Jiwu Huang,Zhimin Yin 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5

The mechanical properties, corrosion behavior and microstructures of the Al–Zn–Mg–Cu alloy under various ageing treatmentswere investigated comparatively. The results show that the tensile strength and corrosion resistance are stronglyaff ected by the precipitate state. Massive fi ne intragranular precipitates contribute to high strength. Discontinuous coarsegrain boundary precipitates containing high Cu content, as well as the narrow precipitate free zone, result in low corrosionsusceptibility. After the non-isothermal ageing (NIA) treatment, the tensile strength of 577 MPa is equivalent to that of579 MPa for the T6 temper. Meanwhile, the stress corrosion susceptibility r tf and the maximum corrosion depth are 97.8%and 23.5 μm, which are comparable to those of 92.8% and 26.7 μm for the T73 temper. Moreover, the total ageing timeof the NIA treatment is only 7.25 h, which is much less than that of 48.67 h for the retrogression and re-ageing condition.

Flow Field Analysis of Lubricating Air Film in Aerostatic Restrictor with Double U-shaped Pressure-Equalizing Grooves

Jianlong Yin,Jing Yu,Cheng Lou,Dongsheng Li,Xiaoyan Shen,Ming Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.2

In an aerostatic restrictor, the presence of friction between the high-pressure air and the aerostatic restrictor wall can lead to non-uniform pressure and temperature distributions of the lubricating air film, which will affect the aerostatic restrictor performance. Therefore, explicating the pressure and temperature distributions of the lubricating air film could help to improve the characteristics and performance of the aerostatic restrictor. In this study, a theoretical model is established for the pressure and temperature distributions in the aerostatic restrictor with double U-shaped pressure-equalizing grooves, which is then compared with simulations, and finally verified by experiments. The results indicate the following. (1) The parameter distributions of the aerostatic restrictor’s air film are affected by the pressure-equalizing grooves and the orifice. (2) The air film parameter distributions are affected by the air source pressure and air film thickness. (3) The air film parameter distribution characteristics obtained from theoretical calculations, simulations, and experiments are consistent, indicating that the theoretical model is effective for studying the flow field of lubricating air film in the aerostatic restrictor. This model can also provide a theoretical basis for designing the orifice and pressure-equalizing grooves of the aerostatic restrictor, as well as selecting the air source pressure and air film thickness.

Hardening and toughening mechanisms in nanotwinned ceramics

Li, Xiaoyan,Yin, Sheng,Oh, Sang Ho,Gao, Huajian Elsevier 2017 Scripta materialia Vol.133 No.-

<P><B>Abstract</B></P> <P>Recent experiments have reported that nanotwinned ceramics with covalent or ionic bonds exhibit unprecedented hardness, enhanced fracture toughness and improved thermal stability. In this viewpoint paper, we highlight some preliminary studies on mechanical properties of nanotwinned ceramics either synthesized in the laboratory or extracted from biological materials, with an emphasis on their hardening and toughening mechanisms from the point of view of defects and bonding structures. Some discussions are also made on possible future research directions, such as exploring underlying deformation mechanisms via in situ TEM testing and large-scale atomistic simulations, and investigating the twin size and orientation effects.</P>

Research on Constitutive Models and Hot Workability of As-Homogenized Al- Zn-Mg-Cu Alloy During Isothermal Compression

Dan Xiao,Xiaoyan Peng,Xiaopeng Liang,Ying Deng,Guofu Xu,Zhimin Yin 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.3

Hot compression tests of as-homogenized Al-Zn-Mg-Cu alloy were performed at the deformation temperaturerange of 350-450 °C and the strain rate range of 0.001-1 s-1. The Arrhenius-type constitutive equation and theAvrami-type model were established to predict the flow behaviors of the alloy respectively. The processing map atthe true strain of 0.92 was developed to evaluate the workability of the alloy and the related microstructures wereinvestigated. The results show that the Avrami-type model has a higher accuracy to predict flow stress than theArrhenius-type constitutive equation. The stable deformation occurs under high temperature or low strain ratemainly owing to the dynamic recrystallization. Flow instability is prone to occur under the condition of low temperatureand high strain rate due to the initiation and the propagation of micro-cracks. According to the processingmap and corresponding microstructure characteristics, the optimum processing parameters are in the temperaturerange of 380-405 °C and the strain rate range of 0.006-0.035 s-1.

관광객 공유한 사진 및 머신 러닝을 활용한 도시 색채 특성 분석 연구 - 중국 대리시를 대상으로 -

인샤오옌,정태열,Yin, Xiaoyan,Jung, Taeyeol 한국조경학회 2024 韓國造景學會誌 Vol.52 No.2

Color is an essential visual element that has a significant impact on the formation of a city's image and people's perceptions. Quantitative analysis of color in urban environments is a complex process that has been difficult to implement in the past. However, with recent rapid advances in Machine Learning, it has become possible to analyze city colors using photos shared by tourists. This study selected Dali City, a popular tourist destination in China, as a case study. Photos of Dali City shared by tourists were collected, and a method to measure large-scale city colors was explored by combining machine learning techniques. Specifically, the DeepLabv3+ model was first applied to perform a semantic segmentation of tourist sharing photos based on the ADE20k dataset, thereby separating artificial elements in the photos. Next, the K-means clustering algorithm was used to extract colors from the artificial elements in Dali City, and an adjacency matrix was constructed to analyze the correlations between the dominant colors. The research results indicate that the main color of the artificial elements in Dali City has the highest percentage of orange-grey. Furthermore, gray tones are often used in combination with other colors. The results indicated that local ethnic and Buddhist cultures influence the color characteristics of artificial elements in Dali City. This research provides a new method of color analysis, and the results not only help Dali City to shape an urban color image that meets the expectations of tourists but also provide reference materials for future urban color planning in Dali City.

Fire-Induced Failure of Long-Term Service and Fresh Concrete Beams Subjected to Fire

Meng Wang,Zhen Guo,Xiaoyan Jia,Yue Yin,Chuang Ma 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.10

In engineering, reinforced concrete beams are subjected to natural erosion and the working stress state. However, previous studies regarding structural fire have focused on new concrete beams, and most results are obtained from no-stress-state tests. Hence, research that considers the natural erosion and working stress states of beam members in fire is lacking. In this study, fire experiments were performed to investigate the differences between long-term service concrete beams and new elements under loads. A technique using ARAMIS three-dimensional (3D) optical strain measurement was adopted; it provides increased sample throughput and 3D measurements that indicate the change in strain more intuitively. Results show that the moisture content of concrete determines the spalling degree of concrete under the influence of working stress. With the increase of concrete moisture content, the range of temperature of heated and backfire surface increases and the spalling phenomenon is more obvious, especially when the moisture content exceeds 2.5%. In addition, the long-term service specimens are affected by fire more easily, thereby accelerating the destruction process owing to the degree of carbonation.

A location-sensitive over-the-counter medicines recommender based on tensor decomposition

Hao, Fei,Park, Doo-Soon,Yin, Xiaoyan,Wang, Xiaoming,Phonexay, Vilakone Springer-Verlag 2019 The Journal of supercomputing Vol.75 No.4