Low-temperature sintering of KNN with excess alkaline elements and the study of its ferroelectric domain structure

Yongjie Zhao,Rongxia Huang,Rongzheng Liu,Heping Zhou,Wei Zhao 한국물리학회 2013 Current Applied Physics Vol.13 No.9

In the present work, lead-free K0.48Na0.52NbO3 (KNN) ceramics were synthesized by conventional ceramicsprocesses. The excess 3.3 mol% Na2CO3 and 1.1 mol% K2CO3 were added to decrease the sinteringtemperature to 990 ℃ and effectively promote the densification of KNN ceramics. X-ray diffraction resultsindicated that the excess Na2CO3 and K2CO3 would induce the formation of the A-site riched secondaryphase with the sintering temperature. Compositional segregation phenomenon enhanced bydifferent sintering temperature, spurs the formation of secondary phase in KNN-AEe ceramics. Inaddition, the difference between ferroelectric domain structure of the poled and as-sintered KNN-AEesamples for 990 ℃ was investigated. Via XRD analysis and SEM observation, it was found that the domainorientation was urged during the poling process.

Sulforaphane kills Mycobacterium tuberculosis H37Ra and Mycobacterium smegmatis mc2155 through a reactive oxygen species dependent mechanism

Zhao Yongjie,Shang Shengwen,Song Ya,Li Tianyue,Han Mingliang,Qin Yuexuan,Wei Meili,Xi Jun,Tang Bikui 한국미생물학회 2022 The journal of microbiology Vol.60 No.11

Mycobacterium tuberculosis (M. tuberculosis) is a highly pathogenic intracellular pathogen that causes tuberculosis (TB), the leading cause of mortality from single infections. Redox homeostasis plays a very important role in the resistance of M. tuberculosis to antibiotic damage and various environmental stresses. The antioxidant sulforaphane (SFN) has been reported to exhibit anticancer activity and inhibit the growth of a variety of bacteria and fungi. Nonetheless, it remains unclear whether SFN exhibits anti-mycobacterial activity. Our results showed that the SFN against M. tuberculosis H37Ra exhibited bactericidal activity in a time and dose-dependent manner. The anti-tubercular activity of SFN was significantly correlated with bacterial reactive oxygen species (ROS) levels. In addition, SFN promoted the bactericidal effect of macrophages on intracellular bacteria in a dose-dependent manner, mediated by increasing intracellular mitochondrial ROS levels and decreasing cytoplasmic ROS levels. Taken together, our data revealed the previously unrecognized antimicrobial functions of SFN. Future studies focusing on the mechanism of SFN in macrophages against M. tuberculosis are essential for developing new host-directed therapeutic approaches against TB.

Knee-driven many-objective sine-cosine algorithm

Hongxia Zhao,Yongjie Wang,Maolin Li 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.2

When solving multi-objective optimization problems, the blindness of the evolution direction of the population gradually emerges with the increase in the number of objectives, and there are also problems of convergence and diversity that are difficult to balance. The many-objective optimization problem makes some classic multi-objective optimization algorithms face challenges due to the huge objective space. The sine cosine algorithm is a new type of natural simulation optimization algorithm, which uses the sine and cosine mathematical model to solve the optimization problem. In this paper, a knee-driven many-objective sine-cosine algorithm (MaSCA-KD) is proposed. First, the Latin hypercube population initialization strategy is used to generate the initial population, in order to ensure that the population is evenly distributed in the decision space. Secondly, special points in the population, such as nadir point and knee points, are adopted to increase selection pressure and guide population evolution. In the process of environmental selection, the diversity of the population is promoted through diversity criteria. Through the above strategies, the balance of population convergence and diversity is achieved. Experimental research on the WFG series of benchmark problems shows that the MaSCA-KD algorithm has a certain degree of competitiveness compared with the existing algorithms. The algorithm has good performance and can be used as an alternative tool for many-objective optimization problems.

LSM-Tree 기반 Key-Value Store의 Write Stall 심층

Guangxun Zhao,신호진(Hojin Shin),Yongjie Zhu,최종무(Jongmoo Choi) 한국정보과학회 2023 한국정보과학회 학술발표논문집 Vol.2023 No.12

Effects of sintering temperature and alkaline elements excess on the structure and electrical properties of (K_0.462Na_0.48Li_0.058)_(1+x)NbO_3 lead-free piezoelectric ceramics

Rongxia Huang,Yuzhen Zhao,Yongjie Zhao,Rongzheng Liu,Heping Zhou 한국물리학회 2011 Current Applied Physics Vol.11 No.5

Lead-free (K_0.462Na_0.48Li_0.058)_(1+x)NbO_3(0 ≤ x ≤ 0.03) ceramics with excessive alkaline elements were synthesized by conventional ceramics processes as functions of sintering temperatures and quantities of excess alkaline elements. X-ray diffraction results reveal a transformation from tetragonal phase to orthorhombic phase with increasing the contents of excessive alkaline elements. The grain size and the piezoelectric properties were enhanced when a certain amount of excessive alkaline elements were added. Further elevation in the amount of alkaline elements added resulted in excessive liquid phase in the ceramics and deteriorated the piezoelectric properties. With x = 0.01, the ceramics sintered at 1050 ℃ show better properties of planar electromechanical coupling factor k_p = 43.4%, piezoelectric constant d_33 = 204 pC/N, dielectric constant ε^T_33/ε_0 = 704.4, and loss tangent tan δ = 2.8%.

A BMI Approach for H2 Based Decomposition

Zhishen Wang,Lei Liu,Yongji Wang,Dangjun Zhao 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.3

The problem of static precompensator design for uncertain system to reduce the coupling is considered in this paper. Diagonal dominant is redefined using the H2 norm of the system. Based on this definition, the necessary and sufficient conditions for system diagonal dominant, which are described by Linear Matrix Inequalities (LMIs), are derived. These conditions are extended to design static precompensator for both nominal system and uncertain system. The conditions are in the form of Bilinear Matrix Inequalities (BMIs), and the combined bisection and path-following algorithm is de-veloped to solve the BMIs. An example is given to show the effectiveness of the proposed method.

Anterior Gradient 3 Promotes Breast Cancer Development and Chemotherapy Response

Qiao Xu,Ying Shao,Jinman Zhang,Huikun Zhang,Yawen Zhao,Xiaoli Liu,Zhifang Guo,Wei Chong,Feng Gu,Yongjie Ma 대한암학회 2020 Cancer Research and Treatment Vol.52 No.1

Purpose Anterior gradient 3 (AGR3) belongs to human anterior gradient (AGR) family. The function of AGR3 on cancer remains unknown. This research aimed to investigate if AGR3 had prognostic values in invasive ductal carcinoma (IDC) of breast cancer and could promote tumor progression. Materials and Methods AGR3 expression was detected in breast benign lesions, ductal carcinoma in situ and IDC by immunohistochemistry analysis. AGR3’s correlations with clinicopathological features and prognosis of IDC patients were analyzed. By cell function experiments, collagen gel droplet-embedded culture drug sensitivity test and cytotoxic analysis, AGR3’s impacts on proliferation, invasion ability, and chemotherapeutic drug sensitivity of breast cancer cells were also detected. Results AGR3 was up-regulated in luminal subtype of histological grade I-II of IDC patients and positively correlated with high risks of recurrence and distant metastasis. AGR3 high expression could lead to bone or liver metastasis and predict poor prognosis of luminal B. In cell lines, AGR3 could promote proliferation and invasion ability of breast cancer cells which were consistent with clinical analysis. Besides, AGR3 could indicate poor prognosis of breast cancer patients treated with taxane but a favorable prognosis with 5-fluoropyrimidines. And breast cancer cells with AGR3 high expression were resistant to taxane but sensitive to 5-fluoropyrimidines. Conclusion AGR3 might be a potential prognostic indicator in luminal B subtype of IDC patients of histological grade I-II. And patients with AGR3 high expression should be treated with chemotherapy regimens consisting of 5-fluoropyrimidines but no taxane.