Synthesis of 4-arms hydroxy-functionalized PMMA-b-PE through combining free radical polymerization with coordination polymerization

Yaping Sheng,Qigu Huang,Haibing Huang,Mengshan Yu,Xinli Zhang,Lu Cheng,Zhi Liu,Wei Liu,Jianjun Yi,Wantai Yang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.2

The copolymerization of MMA with ethylene was promoted by metallocene complex in the presence ofinitiator tetra(2,3-epoxy propoxy)silane (Is), reducing agent Zn and cocatalyst MAO, combining freeradical polymerization with coordination polymerization via sequential monomer addition strategy inone-pot to produce 4-arms hydroxy-functionalized PMMA-b-PE. The effects of polymerizationconditions such as temperature, time, ethylene pressure and Al/Ti molar ratio on the polymerizationperformance were investigated. 4-Arms hydroxy-functionalized PMMA-b-PE was obtained by solventextraction and determined by GPC, MALLS, DSC, FT-IR, WAXD and 1H(13C) NMR. The DSC result indicatedthat the 4-arms hydroxy-functionalized PMMA-b-PE had one Tg at 87.0 ℃ and one Tm at 117.0 ℃ whichattributed to Tg of PMMA segment and Tm of PE segment, respectively. The microstructure of 4-armshydroxy-functionalized PMMA-b-PE was further confirmed by WAXD, FT-IR, and 13C NMR analysis. These results demonstrated that the obtained 4-arms block copolymer consisted of PMMA segment andcrystalline PE segment.

Air Recirculation and Its Effect on Microfiber Spinning in Blunt-Die Melt Blowing

Sheng Xie,Guojun Jiang,Xianyan Wu,Yaping Wang,Haisu Fang,Baoqing Shentu 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

In the present work, approaches of the Computational Fluid Dynamics (CFD) simulation, the Particle ImageVelocimetry (PIV) measurement, and the spinning experiment were applied to investigate the phenomenon of air recirculation inblunt-die melt-blown airflow. Firstly, the characteristics of air recirculation were explored by CFD simulation. The simulationresults predicted that the air recirculation generated a lateral air velocity along the nose-piece direction. Then, the aircirculation was experimental verified by using PIV technique. The PIV results confirmed the predicted conclusions of CFDsimulation. Finally, the effect of air recirculation on the microfiber spinning during the melt-blown process was experimentallyinvestigated by a spinning experiment using a blunt die with nose-piece width of 2.56 mm. The spinning results indicated thatthe air circulation had a tendency of splitting the normal polymeric stream, which played negative effect on the continuity ofmicrofiber spinning. This work is expected to provide some clues to melt-blown die design and the quality control ofnonwoven products.

Prediction of rolling bearing performance degradation based on sae and TCNattention models

Yaping Wang,Dekang Hou,Di Xu,Sheng Zhang,Chaonan Yang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

A single feature cannot show the operational state of a bearing during its entire life cycle. Therefore, a rolling bearing performance deterioration prediction method based on an SAE and the TCN-attention model is proposed. The SAE method is used to fuse the timedomain indicator and the frequency-domain indicator to construct the performance degradation characteristic indicator. The evaluation indices are used to comprehensively evaluate multiple performance degradation indices, and the fused feature indices together, to filter out the features that have a good overall performance. Attention is added to the TCN model, and the output state weight of the TCN model is calculated through a scoring function to increase the important information weight and the prediction accuracy. The appropriate network structure and parameter configuration are determined, and the rolling bearing performance degradation prediction model is established. A validation is performed using publicly available datasets from the University of Cincinnati and XJTU-SY. The results show that the method is more sensitive to the critical information part of the long time series than the other models. At the same time, the average absolute error and the root mean square error are minimized, the accuracy of the rolling bearing performance degradation prediction is high, and the model has a strong robustness and generalization abilities. Additionally, the model has practical engineering value for predicting the health status of equipment.

Physical properties of tetragonal transition-metal borides Nb2MB2 (M = Mo, W, Re or Os) with a new superstructure

Xiaofeng Li,Yaping Tao,Ziyu Hu,Shengli Zhang 한국물리학회 2015 Current Applied Physics Vol.15 No.9

The mechanical and thermodynamic properties, chemical bonding characteristics and electronic structure of Nb2MB2 (M = Mo, W, Re or Os) with a new tetragonal U3Si2-type superstructure (space group P4/ mnc, no. 128) were studied by means of density functional theory calculations. All Nb2MB2 structures studied were demonstrated to be thermodynamically and mechanically stable. The bulk, shear and Young's moduli, Poisson's ratio, Debye temperature and anisotropy factors were derived for ideal polycrystalline Nb2MB2 aggregates. Among these compounds, Nb2WB2 was found to have the highest shear modulus and hardness. The electronic densities of state and electronic localization function analysis revealed the metallicity and strong covalent BeB, NbeB and MB bonding in Nb2MB2. Moreover, these results reveal that the covalence between Nb 4d, M nd (n = 4 for Mo and 5 for W, Re and Os) and B 2p states is the cause of the relatively higher elastic modulus and hardness of the Nb-based compounds. Finally, thermodynamic properties, including the bulk modulus, heat capacity and thermal expansion coefficient of Nb2WB2 were obtained systematically under high temperature and pressure.

A phase II trial of cytoreductive surgery combined with niraparib maintenance in platinum-sensitive, secondary recurrent ovarian cancer: SGOG SOC-3 study

Ting-Yan Shi,Sheng Yin,Jianqing Zhu,Ping Zhang,Jihong Liu,Libing Xiang,Yaping Zhu,Sufang Wu,Xiaojun Chen,Xipeng Wang,Yin-Cheng Teng,Tao Zhu,Aijun Yu,Yingli Zhang,Yanling Feng,He Huang,Wei Bao,Yanli Li 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.3

Background: In China, secondary cytoreductive surgery (SCR) has been widely used in ovarian cancer (OC) over the past two decades. Although Gynecologic Oncology Group-0213 trial did not show its overall survival benefit in first relapsed patients, the questions on patient selection and effect of subsequent targeting therapy are still open. The preliminary data from our pre-SOC1 phase II study showed that selected patients with second relapse who never received SCR at recurrence may still benefit from surgery. Moreover, poly(ADP-ribose) polymerase inhibitors (PARPi) maintenance now has been a standard care for platinum sensitive relapsed OC. To our knowledge, no published or ongoing trial is trying to answer the question if patient can benefit from a potentially complete resection combined with PARPi maintenance in OC patients with secondary recurrence. Methods: SOC-3 is a multi-center, open, randomized, controlled, phase II trial of SCR followed by chemotherapy and niraparib maintenance vs chemotherapy and niraparib maintenance in patients with platinum-sensitive second relapsed OC who never received SCR at recurrence. To guarantee surgical quality, if the sites had no experience of participating in any OC-related surgical trials, the number of recurrent lesions evaluated by central-reviewed positron emission tomography–computed tomography image shouldn't be more than 3. Eligible patients are randomly assigned in a 1:1 ratio to receive either SCR followed by 6 cycles of platinum-based chemotherapy and niraparib maintenance or 6 cycles of platinum-based chemotherapy and niraparib maintenance alone. Patients who undergo at least 4 cycles of chemotherapy and must be, in the opinion of the investigator, without disease progression, will be assigned niraparib maintenance. Major inclusion criteria are secondary relapsed OC with a platinum-free interval of no less than 6 months and a possibly complete resection. Major exclusion criteria are borderline tumors and non-epithelial ovarian malignancies, received debulking surgery at recurrence and impossible to complete resection. The sample size is 96 patients. Primary endpoint is 12-month non-progression rate. Trial Registration: ClinicalTrials.gov Identifier: NCT03983226

Metal Adsorbate-Induced Plasmon Damping in Gold Nanorods: The Difference Between Metals

Pengyu Xu,Xuxing Lu,Junwei Zhao,Yue Li,Sheng Chen,Junfei Xue,Weihui Ou,Song Han,YAPING DING,Weihai Ni 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9

We presented a single particle study on the metal adsorbate-induced plasmon damping in Au nanorods (AuNRs) through adsorbing clusters of different metals including Pt, Au and Ag. AuNRs with different longitudinal surface plasmon resonance (LSPR) wavelength were measured and investigated individually. Linewidth broadening, plasmon shift and reduction of plasmonic resonance of single AuNRs were studied and compared between Pt, Au and Ag adsorbates. The measured linewidths perfectly match the theoretical predictions of the billiard model with increased scattering coefficients resulted from the metal adsorbates. The results indicate that the plasmon damping in case of Ag is significantly weaker than Pt and Au, which can be attributed to longer relaxation time of free electrons in Ag and therefore less loss of the oscillating plasmon electrons. In contrast to the red shift observed from Au and Pt, blue shift of the LSPR is observed in case of Ag. It suggests that plasmonic properties brought by the metal adsorbates can exert dramatic influence on the nanoparticle that is adsorbed with. We believe that our study not only provides important understanding on plasmon damping but pave the road for the fabrication of complex nanostructures with two or more metal elements.