Effects of pulsed laser surface remelting on microstructure, hardness and lead-bismuth corrosion behavior of a ferrite/martensitic steel

Hao Wang,Qian Yuan,Linjiang Chai,Ke Zhao,Ning Guo,Jun Xiao,Xing Yin,Bin Tang,Yuqiong Li,Shaoyu Qiu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

A typical ferritic/martensitic (F/M) steel sheet was subjected to pulsed laser surface remelting (LSR) andcorrosion test in lead-bismuth eutectic (LBE) at 550 C. There present two modification zones withdistinct microstructures in the LSRed specimen: (1) remelted zone (RZ) consisting of both bulk d-ferritegrains and martensitic plates and (2) heat-affected zone (HAZ) below the RZ, mainly composed ofmartensitic plates and high-density precipitates. Martensitic transformation occurs in both the RZ andthe HAZ with the Kurdjumov-Sachs and Nishiyama-Wassermann orientation relationships followedconcurrently, resulting in scattered orientations and specific misorientation characteristics. Hardnessesof the RZ and the HAZ are 364 ± 7 HV and 451 ± 15 HV, respectively, considerably higher than that of thematrix (267 ± 3 HV). In oxygen-saturated and oxygen-depleted LBE, thicknesses of oxide layers developed on both the as-received and the LSRed specimens increase with prolonging corrosion time (oxidelayers always thinner under the oxygen-depleted condition). The corrosion resistance of the LSRed F/Msteel in oxygen-saturated LBE is improved, which can be attributed to the grain-refinement acceleratedformation of dense FeeCr spinel. In oxygen-depleted LBE, the growth of oxide layers is very low withboth types of specimens showing similar corrosion resistance

Triptolide Inhibits Histone Methyltransferase EZH2 and Modulates the Expression of Its Target Genes in Prostate Cancer Cells

Tamgue, Ousman,Chai, Cheng-Sen,Hao, Lin,Zambe, John-Clotaire Daguia,Huang, Wei-Wei,Zhang, Bin,Lei, Ming,Wei, Yan-Ming Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

The histone methyltransferase EZH2 (enhancer of zeste homolog 2) plays critical roles in prostate cancer (PCa) development and is a potential target for PCa treatment. Triptolide possesses anti-tumor activity, but it is unknown whether its therapeutic effect relates with EZH2 in PCa. Here we described EZH2 as a target for Triptolide in PCa cells. Our data showed that Triptolide suppressed PCa cell growth and reduced the expression of EZH2. Overexpression of EZH2 attenuated the Triptolide induced cell growth inhibition. Moreover, Triptolide treatment of PC-3 cells resulted in elevated mRNA levels of target genes (ADRB2, CDH1, CDKN2A and DAB2IP) negatively regulated by EZH2 as well as reduced mRNA levelsan of EZH2 positively regulated gene (cyclin D1). Our findings suggest the PCa cell growth inhibition mediated by Triptolide might be associated with downregulation of EZH2 expression and the subsequent modulation of target genes.

Preparation and Properties of the Fast-Curing γ-Ray-Shielding Materials Based on Polyurethane

Minxuan Ni,Xiaobin Tang,Hao Chai,Yun Zhang,Tuo Chen,Da Chen 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.6

In this study, fast-curing shielding materials were prepared with a two-component polyurethane matrix and a filler material of PbO through a one-step, laboratory-scale method. With an increase in the filler content, viscosity increased. However, the two components showed a small difference. Curing time decreased as the filler content increased. The minimum tack-free time of 27 s was obtained at a filler content of 70 wt%. Tensile strength and compressive strength initially increased and then decreased as the filler content increased. Even when the filler content reached 60 wt%, mechanical properties were still greater than those of the matrix. Cohesional strength decreased as the filler content increased. However, cohesional strength was still greater than 100 kPa at a filler content of 60 wt%. The γ-ray-shielding properties increased with the increase in the filler content, and composite thickness could be increased to improve the shielding performance when the energy of γ-rays was high. When the filler content was 60 wt%, the composite showed excellent comprehensive properties.

Preparation and characteristics of a flexible neutron and g-ray shielding and radiation-resistant material reinforced by benzophenone

Pin Gong,Minxuan Ni,Hao Chai,Feida Chen,Xiaobin Tang 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.3

With a highly functional methyl vinyl silicone rubber (VMQ) matrix and filler materials of B4C, PbO, andbenzophenone (BP) and through powder surface modification, silicone rubber mixing, and vulcanizedmolding, a flexible radiation shielding and resistant composite was prepared in the study. The dispersionproperty of the powder in the matrix filler was improved by powder surface modification. BP was addedinto the matrix to enhance the radiation resistance performance of the composites. After irradiation, thetensile strength, elongation, and tear strength of the composites decreased, while the Shore hardness ofthe composites and the crosslinking density of the VMQ matrix increased. Moreover, the compositeswith BP showed better mechanical properties and smaller crosslinking density than those without BPafter irradiation. The initial degradation temperatures of the composites containing BP before and afterirradiation were 323.6 C and 335.3 C, respectively. The transmission of neutrons for a 2-mm thicksample was only 0.12 for an AmeBe neutron source. The transmission of g-rays with energies of 0.662,1.173, and 1.332 MeV for 2-cm thick samples were 0.7, 0.782, and 0.795, respectively

User Bias Drift Social Recommendation Algorithm based on Metric Learning

Jianli Zhao,Tingting Li,Shangcheng Yang,Hao Li,Baobao Chai 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.12

Social recommendation algorithm can alleviate data sparsity and cold start problems in recommendation system by integrated social information. Among them, matrix-based decomposition algorithms are the most widely used and studied. Such algorithms use dot product operations to calculate the similarity between users and items, which ignores user’s potential preferences, reduces algorithms’ recommendation accuracy. This deficiency can be avoided by a metric learning-based social recommendation algorithm, which learns the distance between user embedding vectors and item embedding vectors instead of vector dot-product operations. However, previous works provide no theoretical explanation for its plausibility. Moreover, most works focus on the indirect impact of social friends on user’s preferences, ignoring the direct impact on user’s rating preferences, which is the influence of user rating preferences. To solve these problems, this study proposes a user bias drift social recommendation algorithm based on metric learning (BDML). The main work of this paper is as follows: (1) the process of introducing metric learning in the social recommendation scenario is introduced in the form of equations, and explained the reason why metric learning can replace the click operation; (2) a new user bias is constructed to simultaneously model the impact of social relationships on user’s ratings preferences and user’s preferences; Experimental results on two datasets show that the BDML algorithm proposed in this study has better recommendation accuracy compared with other comparison algorithms, and will be able to guarantee the recommendation effect in a more sparse dataset.

Personality Characteristics of Male Sufferers of Chronic Tension-Type and Cervicogenic Headache

Wanzhen Chen,Shaohua Yu,Junpeng Zhu,Hao Chai,Wei He,Wei Wang 대한신경과학회 2012 Journal of Clinical Neurology Vol.8 No.1

Background and Purpose Chronic tension-type headache (a primary headache disorder)and cervicogenic headache (a secondary headache disorder that is attributable to upper cervical spine pathology) share similar clinical manifestations, but their associated personality traits may differ. We evaluated the personality differences between sufferers of chronic tension-type headache and cervicogenic headache. Methods We administered the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ) and the Zuckerman Sensation-Seeking Scale (SSS) to 18 patients suffering from chronic tensiontype headache, 19 suffering from cervicogenic headache, and 26 healthy volunteers. Depressive trends were measured with the Plutchik-van-Praag Depression Inventory (PVP). Results Compared to healthy controls, the chronic tension-type headache group scored significantly higher on ZKPQ Neuroticism-Anxiety and on the PVP, while the cervicogenic headache group scored significantly lower on SSS Thrill and Adventure Seeking. In addition, the total SSS score was significantly lower in the cervicogenic headache group than in both the chronic tension-type headache group and the healthy controls. Conclusions The results of this study indicate that higher scores for neuroticism-anxiety and depression were associated with chronic tension-type headache, while lower sensation-seeking scores were associated with cervicogenic headache.

Research on grid‑connected harmonic current suppression of three‑phase four‑wire energy storage inverters

Hongyang Qing,Chunjiang Zhang,Xiuhui Chai,Hao He,Xiaohuan Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.6

When a three-phase four-wire grid-connected energy storage inverter is connected to unbalanced or single-phase loads, a large grid-connected harmonic current is generated due to the existence of a zero-sequence channel. A controller design approach for grid-connected harmonic current suppression is proposed based on proportion–integral–repetitive (PI–repetitive) control for a three-level neutral point clamped (3L-NPC) three-phase four-wire inverter. By designing the variable parameters n (gain coeffi cient of the PI controller) and Qs (gain of the repetitive controller), the eff ect of the PI–repetitive controller gain on current harmonic suppression is analyzed using a three-dimensional amplitude gain curve. A simplifi ed impedance model in the d 0-frame for a three-phase four-wire inverter is proposed. Based on the impedance model in the d0-frame, the system stability is analyzed under diff erent PI–repetitive control gains by the generalized Nyquist criterion. Finally, the optimal controller design is obtained by a gain characteristic and system stability analysis. The controller obtained by this harmonic suppression analysis method can simultaneously ensure the best grid-connected current quality of the three-phase four-wireinverter and the dynamic stability of the system. Simulation and experimental results verify the effectiveness and correctness of the proposed controller design approach for grid-connected harmonic current suppression.

Protective Effects of Chalcone Derivatives for Acute Liver Injury in Mice

Guan Li-Ping,Nan Ji-Xing,Jin Xue-Jun,Jin Qing-Hao,Kwak Kyung Chell,Chai Kyu-yun,Quan Zhe-Shan The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.1

The hepatoprotective effects of chalcone derivatives were evaluated in D-galactosamine/lipopolysaccharide (D-GaIN/LPS)-induced fulminant hepatic failure in mouse. Thirteen chalcone derivatives were synthesized for study and their hepatoprotective effects were evaluated by assessing aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in serum. Chalcone preparations were injected into mice at 12 hand 1 h before intraperitoneal injection of D-GaIN/LPS. After abdominal administration, changes in AST and ALT between the control and treated groups were observed. Ten of the synthesized chalcone derivatives exhibited inhibitory effects on D-GaIN/LPS-induced levels of AST and ALT in mice. Compounds 2, 3, 8, 9, and 12 markedly reduced serum AST and ALT at 8 h, inhibited hepatocyte necrosis and showed significant hepatoprotective activities. The activity of compound 3 was compared with the bifendate (DDB) through oral administration. Compound 3 showed much higher inhibitory effects than bifendate for decreasing AST and ALT activity. The results indicate that compound 3 has strong hepatoprotective activity through suppression of tumor necrosis factor­alpha (TNF-alpha) preduction, reduction of the histological change in the liver, and attenuated of hepatocyte apoptosis confirmed by DNA fragmentation assay.

Electrochemical Behavior of Sm(III) on the Aluminium-Gallium Alloy Electrode in LiCl-KCl Eutectic

Ye, Chang-Mei,Jiang, Shi-Lin,Liu, Ya-Lan,Xu, Kai,Yang, Shao-Hua,Chang, Ke-Ke,Ren, Hao,Chai, Zhi-Fang,Shi, Wei-Qun Korean Radioactive Waste Society 2021 방사성폐기물학회지 Vol.19 No.2

In this study, the electrochemical behavior of Sm on the binary liquid Al-Ga cathode in the LiCl-KCl molten salt system is investigated. First, the co-reduction process of Sm(III)-Al(III), Sm(III)-Ga(III), and Sm(III)-Ga(III)-Al(III) on the W electrode (inert) were studied using cyclic voltammetry (CV), square-wave voltammetry (SWV) and open circuit potential (OCP) methods, respectively. It was identified that Sm(III) can be co-reduced with Al(III) or Ga(III) to form Al_zSm_y or Ga_xSm_y intermetallic compounds. Subsequently, the under-potential deposition of Sm(III) at the Al, Ga, and Al-Ga active cathode was performed to confirm the formation of Sm-based intermetallic compounds. The X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses indicated that Ga₃Sm and Ga₆Sm intermetallic compounds were formed on the Mo grid electrode (inert) during the potentiostatic electrolysis in LiCl-KCl-SmCl₃-AlCl₃-GaCl₃ melt, while only Ga₆Sm intermetallic compound was generated on the Al-Ga alloy electrode during the galvanostatic electrolysis in LiCl-KCl-SmCl₃ melt. The electrolysis results revealed that the interaction between Sm and Ga was predominant in the Al-Ga alloy electrode, with Al only acting as an additive to lower the melting point.