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Synthesis and characterization of carbazole-based dendrimers as bipolar host materials for green phosphorescent organic light emitting diodes

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Chinese Chemical Letters 2016年第3期27卷 441-446页

作者： Ting Zhang Dong-Qing Xu jun-ming chen Ping Zhang Xu-Chun Wang School of Chemistry and Material Engineering Anhui Science and Technology University Center of Analysis and Measurement Anhui Science and Technology University

A group of novel, carbazole-based dendrimers comprised of the electron-accepting dibenzothiophene core and the electron-donating oligo-carbazole dendrons, namely G1 SF and G2 SF, are synthesized utilizing the Ullmann C–N coupling reaction. The dendrimers are designed in such a way to show good solubility in common organic solvents, excellent thermochemical stability with decomposition temperatures（Td） up to430 8C, and high HOMO levels in a range from 5.45 e V to 5.37 e V. Results of density functional theory calculations（DFT） indicate G2 SF has an almost complete separation of HOMO and LUMO levels at the holeand electron-transporting moieties; while G1 SF exhibits only partial separation of the HOMO and LUMO levels possibly due to intramolecular charge transfer. Green phosphorescent OLEDs were fabricated by the spin coating method with the dendrimers as hosts and traditional green iridium phosphor as doped emitter. Under ambient conditions, a maximum luminance efficiency（hL） of 19.83 cd A^-1and a maximum external quantum efficiency of 5.85% are achieved for G1 SF, and 15.50 cd A ^-1and 4.57% for G2 SF.

关键词： OLEDs Bipolar host materials Dendrimer Carbazole Dibenzothiophene

Sensing Matrix Optimization for Random Stepped-Frequency Signal Based on Two-Dimensional Ambiguity Function

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Chinese Journal of Electronics 2024年第1期33卷 161-174页

作者： mingjiu LYU Hao chen jun YANG Xia WU ming ZHOU Xiaoyan MA Radar NCO School Air Force Early Warning Academy Department of Early Warning Technology Air Force Early Warning Academy

Compressive sensing technique has been widely applied to achieve range-Doppler reconstruction of high frequency radar by utilizing sparse random stepped-frequency(SRSF) signal, which can suppress the complex electromagnetic interference and greatly reduce the coherent processing interval. An important way to improve the performance of sparse signal reconstruction is to optimize the sensing matrix(SM). However, the existing research on the SM optimization needs to design a measurement matrix with superior performance, which needs a large amount of computation and does not consider the influence of the waveform parameters design. In order to improve the superior reconstruction performance, a novel SM optimization approach for SRSF signal is proposed by using two-dimensional ambiguity function(TDAF) in this paper. Firstly, based on the two-dimensional sparse reconstruction model of the SRSFs, the internal relationship between the waveform parameters and the SM was derived. Secondly, the SM optimization problem was directly transformed into the waveform design of SRSFs. Furthermore, on the basis of analyzing the relationship between the mutual coherence matrix of SM and the TDAF matrix of SRSFs, the purpose of optimizing the SM can be achieved by designing the TDAF of the SRSFs. Based on this analysis, a sparse waveform optimization method with joint constraints of maximum and mean sidelobes of the TDAF by using the genetic algorithm was derived. Compared with the traditional SM optimization method, our method not only avoids generating a new measurement matrix, but also further reduces the complexity of the waveform optimization. Simulation experiments verified the effectiveness of the proposed method.

关键词： Correlation Computational modeling Electromagnetic interference Optimization methods Signal reconstruction High frequency radar Sensors

Qinggan Huoxue Recipe suppresses epithelial-tomesenchymal transition in alcoholic liver fibrosis through TGF-β1/Smad signaling pathway

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World Journal of Gastroenterology 2016年第19期22卷 4695-4706页

作者： Tao Wu jun-ming chen Tie-Gang Xiao Xiang-Bing Shu Han-chen Xu Li-Li Yang Lian-jun Xing Pei-Yong Zheng Guang Ji Center of Chinese Medical Therapy and Systems Biology Shanghai University of Traditional Chinese Medicine Institute of Digestive Disease Longhua Hospital Shanghai University of Traditional Chinese Medicine Department of Traditional Chinese Medicine Shanghai Jiao Tong University Affiliated Sixth People’s Hospital E-institute of Shanghai Municipal Education Committee Shanghai University of Traditional Chinese Medicine

AIM: To investigate the mechanism by which Qinggan Huoxue Recipe (QGHXR) inhibits epithelial-to-mesenchymal transition (EMT) in rats with alcoholic liver fibrosis (ALF).METHODS: A total of 75 male SD rats were used to induce ALF. Serum biochemical indicators, including alanine aminotransferase, aspartate aminotransferase, laminin and hyaluronidase, were measured. Liver histopathological changes were evaluated using hematoxylin-eosin and Sirius red staining. EMT was examined by analyzing the expression of the epithelial marker E-cadherin and the mesenchymal markers vimentin and fibronectin using RT-PCR and Western blot. The inhibitory effect of QGHXR on EMT markers, as well as its effect on molecules associated with the transforming growth factor (TGF)-β1/Smad signaling pathway, including TGF-β1, Smad3, snail, occludin, ZO-1 and claudin, was also ***: Compared with normal control rats, ALF rats exhibited a decrease in E-cadherin levels (mRNA: ALF 0.16 ± 0.05 vs control 1.00 ± 0.08; protein: ALF 0.09 ± 0.05 vs control 0.70 ± 0.17, P < 0.01) and an increase in vimentin and fibronectin levels (mRNA: 11.43 ± 0.39 vs 1.00 ± 0.19 and 9.91 ± 0.34 vs 1.00 ± 0.44, respectively, P < 0.01; protein: 1.13 ± 0.42 vs 0.09 ± 0.03 and 1.16 ± 0.43 vs 0.09 ± 0.00, respectively, P < 0.01). This indicates that EMT occurred in ALF rats. In addition, the TGF-β1/Smad signaling pathway was activated in ALF rats, as evidenced by the increase in TGF-β1 and snail levels (mRNA: 1.76 ± 0.12 vs 1.00 ± 0.05 and 6.98 ± 0.41 vs 1.00 ± 0.10, respectively, P < 0.01; protein: 1.43 ± 0.05 vs 0.12 ± 0.03 and 1.07 ± 0.29 vs 0.07 ± 0.02, respectively, P < 0.01) and the decrease in Smad3 levels (mRNA: 0.05 ± 0.01 vs 1.00 ± 0.12, P < 0.01; prote

关键词： Alcoholic liver fibrosis QGHXR Epithelial-to-mesenchymal transition Snail Transforming growth factor-β 1/Smad

In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

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Nuclear Science and Techniques 2024年第7期35卷 192-207页

作者： ming Xia Yong-jun Ye Shan-Wei Shang Ting Yu Dai-Jia chen School of Resources Environment and Safety Engineering University of South ChinaHengyang421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang421001China

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two *** abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was *** on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and *** in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the *** consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air *** synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

关键词： Radon exhalation Flow-through Numerical simulation Accumulation chamber Multivariate regression

Intelligent geochemical interpretation of mass chromatograms:Based on convolution neural network

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Petroleum Science 2024年第2期21卷 752-764页

作者： Kai-ming Su jun-Gang Lu Jian Yu Zi-Xing Lu Shi-Jia chen Hubei Key Laboratory of Petroleum Geochemistry and Environment Wuhan430100HubeiChina College of Resources and Environment Yangtze UniversityWuhan430100HubeiChina School of Geoscience and Technology Southwest Petroleum UniversityChengdu610500SichuanChina Changqing Oilfield Company PetroChinaXi'an710021ShaanxiChina

Gas chromatography-mass spectrometry(GC-MS)is an extremely important analytical technique that is widely used in organic *** is the only approach to capture biomarker features of organic matter and provides the key evidence for oil-source correlation and thermal maturity ***,the conventional way of processing and interpreting the mass chromatogram is both timeconsuming and labor-intensive,which increases the research cost and restrains extensive applications of this *** overcome this limitation,a correlation model is developed based on the convolution neural network(CNN)to link the mass chromatogram and biomarker features of samples from the Triassic Yanchang Formation,Ordos Basin,*** this way,the mass chromatogram can be automatically *** research first performs dimensionality reduction for 15 biomarker parameters via the factor analysis and then quantifies the biomarker features using two indexes(*** and PMI)that represent the organic matter thermal maturity and parent material type,***,training,interpretation,and validation are performed multiple times using different CNN models to optimize the model structure and hyper-parameter setting,with the mass chromatogram used as the input and the obtained MI and PMI values for supervision(label).The optimized model presents high accuracy in automatically interpreting the mass chromatogram,with R2values typically above 0.85 and0.80 for the thermal maturity and parent material interpretation results,*** significance of this research is twofold:(i)developing an efficient technique for geochemical research;(ii)more importantly,demonstrating the potential of artificial intelligence in organic geochemistry and providing vital references for future related studies.

关键词： Organic geochemistry Biomarker Mass chromatographic analysis Automated interpretation Convolution neural network Machine learning

Durable flame-retardant,smoke-suppressant,and thermal-insulating biomass polyurethane foam enabled by a green bio-based system

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Journal of Materials Science & Technology 2023年第31期162卷 179-188页

作者： Xue-Lian chen Fu-Rong Zeng Wen-Xiong Li Lin Zhang Cong Deng Yi Tan ming-jun chen Sheng-Chao Huang Bo-Wen Liu Yu-Zhong Wang Hai-Bo Zhao The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)College of ChemistryState Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610064China School of Science Xihua UniversityChengdu 610039China Hubei Three Gorges Laboratory Yichang 443199China

Bio-based polyurethane foam has attracted increasing attentions due to eco-friendliness and fossil feedstock ***,the inherent flammability limits its application in different ***,we demonstrate a green bio-based flame-retardant system to fabricate polyurethane foam composite with durable flame retardancy,smoke suppression,and thermal insulation *** this system,the green bio-based polyol(VED)with good reactivity and compatibility plays a role of flame retardant and EG acts as a synergistic *** a result,the LOI value of foam composite increased to 30.5 vol.%and it achieved a V-0 rating in the UL-94 vertical burning ***,the peak heat release rate(pHRR)and the total smoke production(TSP)decreased by 66.1%and 63.4%,***,the foam composite maintained durable flame retardancy after accelerated thermal aging test,whose thermal-insulating property was maintained even after being treated in high-humidity environment with 85%*** a *** work provides a facile strategy for durable flame retardancy and long-term thermal insulation performance,and creates opportunities for the practical applications of bio-based foam composites.

关键词： Biomass polyurethane foam composite Green bio-based system Durable flame retardancy Smoke suppression Long-term thermal insulation

Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

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Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： jun-Hao Zhou Li-ming Tang Key Laboratory of Advanced Materials of Ministry of Education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

FPGA-based position reconstruction method for neutron beam flux spatial distribution measurement in BNCT

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Nuclear Science and Techniques 2024年第3期35卷 96-108页

作者： Wei Jiang Ping Cao Yi-ming Wu Xian-Ke Liu Zhu-jun Fang Zhi-Yong Zhang Bin Shi jun chen State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China National Key Laboratory for Metrology and Calibration Techniques China Institute of Atomic EnergyBeijing 102413China

A new measurement method for the spatial distribution of neutron beam flux in boron neutron capture therapy(BNCT)is being developed based on the two-dimensional Micromegas *** address the issue of long processing times in traditional offline position reconstruction methods,this paper proposes a field programmable gate array based online position reconstruction method utilizing the micro-time projection chamber *** method encapsulates key technical aspects:a self-adaptive serial link technique built upon the dynamical adjustment of the delay chain length,fast sorting,a coordinate-matching technique based on the mapping between signal timestamps and random access memory(RAM)addresses,and a precise start point-merging technique utilizing a circular combined *** performance test of the selfadaptive serial link shows that the bit error rate of the link is better than 10-12 at a confidence level of 99%,ensuring reliable data *** experiment utilizing the readout electronics and Micromegas detector shows a spatial resolution of approximately 1.4 mm,surpassing the current method’s resolution level of 5 *** beam experiment confirms that the readout electronics system can obtain the flux spatial distribution of neutron beams online,thus validating the feasibility of the position reconstruction *** online position reconstruction method avoids traditional methods,such as bubble sorting and traversal searching,simplifies the design of the logic firmware,and reduces the time complexity from O(n2)to O(n).This study contributes to the advancement in measuring neutron beam flux for BNCT.

关键词： Position reconstruction FPGA Readout electronics Neutron flux spatial distribution

Optical modulation of repaired damage site on fused silica produced by CO2 laser rapid ablation mitigation

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Chinese Physics B 2020年第5期29卷 288-296页

作者： Chao Tan Lin-Jie Zhao ming-jun chen Jian cheng Zhao-Yang Yin Qi Liu Hao Yang Wei Liao State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Research Center of Laser Fusion China Academy of Engineering PhysicsMianyang 621900China

CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated *** order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its *** influences of the cone angle and the size of the repaired site on incident laser modulation are studied as *** results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional *** relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of *** the distribution of maximum relative light intensity on y-section is parabolical with the increase of *** the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser ***,the large size repaired site would also reduce the laser damage ***,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface *** work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.

关键词： fused silica laser repaired surface optical modulation finite element method(FEM)