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Zhang, Heyao,He, Zhao,Song, Jinliang,Liu, Zhanjun,Tang, Zhongfeng,Liu, Min,Wang, Yong,Liu, Xiangdong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6
Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He<sup>+</sup> irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.
Zhiwu Zhang,Youping Yi,Wen You,Shiquan Huang,Yonglin Guo,Hailin He 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6
To investigate the quenching sensitivity of the 2195 Al–Li alloy rolled sheet and guide the design of the quenching process,the time–temperature-property (TTP) curves of this material were researched through interrupted quenching experiments. The differential scanning calorimetry (DSC) and transmission electron microscope (TEM) were used to characterize theevolution of precipitates during isothermal treatment. The results of this essay demonstrated that the nose temperature of 2195Al–Li alloy is around 370 °C and the temperature range of quenching sensitivity is 340 °C to 400 °C. The microstructureobservation revealed that the T1particles precipitate and grow rapidly at the temperature from 340 to 400 °C, which is dueto the high nucleation rate of phase and fast solute diffusion kinetics, especially at the nose temperature. The needle-shapedθ′/θ″ and T1particles grow up quickly as the isothermal preservation time prolonged, leading to the decrease of the supersaturatedsolid solution of the matrix. This will reduce the number of the age-induced precipitate and weaken the subsequentage hardening effect. Therefore, the rate of cooling should be increased in the quenching sensitivity range (340–400 °C) toinhibit the precipitation of the second phase and obtain excellent mechanical properties. While in other temperature ranges,the cooling rate should be decreased appropriately to reduce residual stress. The appropriate average cooling rate is recommendedto be around 13 °C s−1 at the temperature from 340 to 400 °C.
Zhang, Hao,Liu, Jing-Sheng,Zhang, He-Xin,Ko, Eun-Bin,Park, Jae-Hyeong,Moon, Young-Kwon,Shin, Byeong-Kwang,Zhang, Xue-Quan,Yoon, Keun-Byoung American Scientific Publishers 2018 Journal of Nanoscience and Nanotechnology Vol.18 No.4
<P>A facile coagglomeration method for preparing a long alkyl chain modified graphene oxide (MGO)/MgCl2-supported Ti-based Ziegler-Natta catalyst was reported. The effects of MGO on the catalyst morphology and activity for ethylene polymerization were examined. The resultant polyethylene (PE)/MGO nanocomposites exhibited a layered morphology, with the MGO fillers being well dispersed and exhibiting strong interfacial adhesion to the PE matrix. The thermal stability and mechanical properties of the PE were significantly enhanced with the introduction of a small amount of the MGO filler. Thus, this work provides a facile approach to the production of high-performance PE.</P>
Zhang, He-xin,Park, Jae-Hyeong,Yoon, Keun-Byoung Elsevier 2018 Composites science and technology Vol.154 No.-
<P><B>Abstract</B></P> <P>Superior electrically conductive PE nanocomposites were prepared with reduced graphene oxide(rGO)-supported MAO cocatalyst via <I>in situ</I> ethylene polymerization. The electrical conductivity of the composites was very high at 1.2 S/m. This value is the highest among reported rGO-filled composites. The cocatalyst system was prepared by modifying with alkoxysilane compound to prevent restacking of the GO plane in the reduction process and solvothermal reduction of GO. The effect of cocatalysts on the properties of nanocomposites and distribution of nanosheets in the polymer matrix was investigated in detail. The mechanical properties and thermal stability of PE/rGO nanocomposites were significantly increased via the addition of a small amount of rGO. These properties resulted from the restacked rGO layers exfoliated <I>in situ</I> by the ethylene insertion between the intercalated layers.</P>
Tas13D Inhibits Growth of SMMC-7721 Cell via Suppression VEGF and EGF Expression
He, Huai-Zhen,Wang, Nan,Zhang, Jie,Zheng, Lei,Zhang, Yan-Min Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5
Objective: Taspine, isolated from Radix et Rhizoma Leonticis has demosntrated potential proctiective effects against cancer. Tas13D, a novel taspine derivative synthetized by structure-based drug design, have been shown to possess interesting biological and pharmacological activities. The current study was designed to evaluate its antiproliferative activity and underlying mechanisms. Methods: Antiproliferative activity of tas13D was evaluated by xenograft in athymic mice in vivo, and by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and cell migration assays with human liver cancer (SMMC-7721) cell lines in vitro. Docking between tas13D and VEGFR and EGFR was studied by with a Sybyl/Surflex module. VEGF and EGF and their receptor expression was determined by ELISA and real-time PCR methods, respectively. Results: Our present study showed that tas13D inhibited SMMC-7721 xenograft tumor growth, bound tightly with the active site of kinase domains of EGFR and VEGFR, and reduced SMMC-7721 cell proliferation (IC=34.7 ${\mu}mol/L$) and migration compared to negative controls. VEGF and EGF mRNAs were significantly reduced by tas13D treatment in a dose-dependent manner, along with VEGF and EGF production. Conclusion: The obtained results suggest that tas13D inhibits tumor growth and cell proliferation by inhibiting cell migration, downregulating mRNA expression of VEGF and EGF, and decreasing angiogenic factor production. Tas13D deserves further consideration as a chemotherapeutic agent.
He, Wentao,Yao, Yong,He, Min,Kai, Zhang,Long, Lijuan,Zhang, Minmin,Qin, Shuhao,Yu, Jie Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1
Surface modification of montmorillonite (MMT) with 3-glycidoxypropyl trimethoxysilane (3GTO) in mild methanol/water mixture has been investigated in detail. The influence of reaction conditions (including silane concentration in feed, reaction time and reaction temperature) on the grafting amount and yield of silane, and further on the grafting pattern of silanes was studied by thermogravimetric analysis, elemental analysis, X-ray diffraction (XRD) and BET. Higher silane concentration, longer reaction time and higher reaction temperature are all benefit to higher grafting amount. When the grafting reaction was performed with 3 mmol/g silane concentration, at $90^{\circ}C$ for 24 h, the grafted amount and yield of silane reached 1.4443 mmol/g and 30%, respectively. Based on the XRD and BET data analysis, a speculation that the grafting pattern of silanes was concentration dependence was proposed.
Zhang Yingchao,He Juan,Zhang Yuxia,Li Yue,Yu Yang,Jiang Xingfu,Pan Weidong 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.2
Growth-blocking peptide (GBP) is a 25 amino acid insect cytokine found in lepidopteran insects that has diverse biological activities such as larval growth regulation, paralysis induction, cell proliferation and stimulation of immune cells. Density-dependent phase polyphenism is a phenomenon of phenotypic plasticity in which the expression of a variety of traits can be affected by local population density. In the present study, the armyworm Mythimna separata larvae with four rearing densities (1 larva/vial, 2 larvae/vial, 4 larvae/vial and 6 larvae/vial) were tested for cuticular melanization and body weight throughout the third-fifth instar, and the functional role of GBP in regulating the changes was investigated. The results indicated that when reared at high densities, the larvae exhibited less body weight and more degree of cuticular melanization than larvae reared at low densities. The gene expression of GBP in armyworm larvae showed an initial rise and then decline trend with increased rearing densities in the third to fifth instar. Compared with control, more degree of cuticular melanization was observed in GBP-injected larvae (500 ng/larva in volume 50 μL) than that in Ringer’s solution-injected counterparts. Furthermore, the gene expression level of dopa decarboxylase and prophenoloxidase increased significantly in GBP-injected fifth instar larvae from 6 h to 12 h after injection, suggesting the role of GBP in modulating density-dependent phase trait of armyworm cuticular melanization.
Zhang Qing,He Yi-Jing,Zhu Yu-Hang,Dai Min-Chen,Pan Man-Man,Wu Jia-Qi,Zhang Xian,Gu Ying-Er,Wang Fang-Fang,Xu Xiang-Rong,Qu Fan 한국한의학연구원 2020 Integrative Medicine Research Vol.9 No.3
Background: During the COVID-19 epidemic period, Traditional Chinese Medicine (TCM) course for international students of Medical Bachelor, Bachelor of Surgery (MBBS) program in Zhejiang University has shifted from traditional classroom to online environment. This study aimed to investigate MBBS international students’ perception on online TCM course, and to assess the online learning efficacy. Methods: A total of 84 MBBS international students attending course of “Basic Traditional Chinese Medicine” during 2020 academic years at Zhejiang University were enrolled in this study. A quantitative questionnaire was respectively completed before and after the TCM course using a pretest–post-test design. By means of two online learning platforms, Learning in ZJU and DingTalk, TCM course was broadcast in both live and archived format to students. Results: A total of 48 participants completed both baseline and follow-up questionnaires. The majority of participants preferred face-to-face classroom learning (26, 54.17% of total) when compared with online learning. Students felt that the course had brought in much benefits (mean 3.88, SD 0.87), and they were satisfied with the course content (mean 3.83, SD 0.95). Students’ TCM related knowledge and their behaviors of discussion and consulting were significantly improved by online TCM course (all P < 0.001). Students’ awareness of the necessity of TCM education and their feeling of difficulty in learning TCM were significantly strengthened (P = 0.042, 0.025, respectively). Conclusion: Online learning is a good alternative for TCM course of MBBS international students when classroom learning is suspended, whereas it cannot replace the need for onsite and face-to-face learning.
A Continuous Abnormal Speech Detection Method Based on Time Domain features Weighted
He Jun,Ji-chen Yang,Qing-hua Zhang,Guo-xi Sun,Jian-bing Xiong 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12
In this brief, a novel pathological continuous speech detection method based on time domain features weighted. First, different optimal threshold for time domain features, including zero crossing ratio, short-time energy and autocorrelation, are obtained from training speech data. Second, a difference evaluation technique is proposed, and with it, the difference of the same time domain feature selected from testing speech data and training speech data were obtained. Finally, to distinguish a given speech well, a novel weighting method based on difference evaluation for each kinds of time domain is employed, respectively. Experiments were conducted on the pathological speech database to prove the power and effectiveness of the proposed method. Results obtained shown that this method outperforms other early proposed time domain feature method, creating a more reliable technique for pathological continuous speech detection.