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Chemical Research in Chinese Universities 2009年第5期25卷 760-766页

作者： FU Qi shi wen-fang Joint Laboratory of Polymer Thin Films and Solution Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 P. R. China

An octa-functional acrylate of C-tetramethyl calix[4]resorcinarene（CMC-4-RA） was facilely synthesized and characterized with ^1H NMR, ^13C NMR and FTIR spectroscopy. The CMC-4-RA was added to a thiol-acrylate system with different mass ratios, and exposed to a middle pressure mercury lamp. The maximum photopolymerization rate and final vinyl group conversion in the cured film increased greatly along with CMC-4-RA addition that was monitored with Photo-DSC. The tensile strength and pendulum hardness were improved significantly after the addition of CMC-4-RA. With increasing the content of CMC-4-RA to 60%（mass fraction）, the glass transition temperature increased from 34.2 ℃ to 84.1 ℃; the cross-link density was calculated to be increased from 23.83 mmol/cm^3 to 82.40 mmol/cm^3 according to dynamic mechanical thermal analysis; the thermostability was greatly improved.

关键词： Calixresorcinarene Acrylate UV curing Film

Hyperbranched Polyurethane Acrylate Applied to UV Curable Flame Retardant Coatings

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Chemical Research in Chinese Universities 2001年第3期17卷 331-333页

作者： ZHU Sheng-Wu shi wen-fang State Key Laboratory of Fire Science Department of Applied ChemistryUniversity of Science and Technology of ChinaHefei 230026P.R.China

UV curable hyperbranched prepolymers based on amine-ester, ester-amide and ether-amide started with AB_2-type monomers have been prepared by the authors. A series of work on allyl ether maleate hyperbranched polyesters for UV curing coatings by Hult and his colleagues has been reported. However, the UV cured films from those materials are all flammable when attached to fire without addition of flame retardants.

关键词： Flame retardant Polyurethane acrylate Phosphorus UV curing

Preparation and Conducting Behavior of Amphibious Organic/Inorganic Hybrid Proton Exchange Membranes Based on Benzyltetrazole

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Chemical Research in Chinese Universities 2012年第2期28卷 345-352页

作者： QIAO Li-gen shi wen-fang CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026P.R.China

A series of novel amphibious organic/inorganic hybrid proton exchange membranes with H3PO4 doped which could be used under both wet and dry conditions was prepared through a sol-gel process based on acrylated triethoxysilane（A-TES） and benzyltetrazole-modified triethoxysilane（BT-TES）.The dual-curing approach including UV-curing and thermal curing was used to obtain the crosslinked *** glycol（400） diacrylate（PEGDA） was used as an oligomer to form the polymeric *** molecular structures of precursors were characterized by 1 H,13 C and 29 Si NMR *** thermogravimetric analysis（TGA） results show that the membranes exhibit acceptable thermal stability for their application at above 200 *** differential scanning calorimeter（DSC） determination indicates that the crosslinked membranes with the mass ratios of below 1.6 of BT-TES to A-TES and the same mass of H3PO4 doped as that of A-TES possess the-T g s,and the lowest T g（-28.9 ℃） exists for the membrane with double mass of H3PO4 doped as *** high proton conductivity in a range of 9.4―17.3 mS/cm with the corresponding water uptake of 19.1%―32.8% of the membranes was detected at 90 oC under wet ***,the proton conductivity in a dry environment for the membrane with a mass ratio of 2.4 of BT-TES to A-TES and double H3PO4 loading increases from 4.89×10-2 mS/cm at 30 ℃ to 25.7 mS/cm at 140 ℃.The excellent proton transport ability under both hydrous and anhydrous conditions demonstrates a potential application in the polymer electrolyte membrane fuel cells.

关键词： Amphibious Benzyltetrazole Organic/inorganic hybrid membrane Phosphorus acid Proton conductivity

Facile Route to Aromatic Hyperbranched Poly(ester amines)

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Chemical Research in Chinese Universities 2009年第3期25卷 400-403页

作者： ZHANG Zheng-hui shi wen-fang Department of Polymer Science and Engineering Joint Laboratory of Polymer Thin Films and Solution University of Science and Technology of China Hefei 230026 P. R. China

The aromatic hyperbranched poly（ester amines）（AHPEAs） were successfully synthesized via the mild condensation of N-4-cyanobenzyl diethanolamine hydrogenchloride as an AB2 monomer in concentrated HCI. The polymerization was monitored by FTIR to suppose the reasonable reaction mechanism. The degree of branching was determined to be 0.55 by 1H NMR with an increased conversion of up to 96%. The glass transition temperature was measured by differential scanning calorimetry to range from -19 to 15℃ The molecular weights and polydispersities were investigated by gel permeation chromatography.

关键词： Hyperbranch Poly(ester amine) 4-Cyanobenzyl chloride Alcoholysis

Photoinitiating Characteristics of Benzophenone Derivatives as Type II Macromolecular Photoinitiators Used for UV Curable Resins

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Chemical Research in Chinese Universities 2011年第1期27卷 145-149页

作者： CHENG Liang-liang ZHANG Yong shi wen-fang CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 P.. R. China

Dodecyl-benzophenone（DBP） and hexadecoxyl-benzophenone（HDBP） as type 11 photoinitiators used for radical photopolymerization systems were synthesized by Friedel-Crafts reaction, and characterized by 1H NMR and FTIR spectroscopy. The UV-Vis absorption spectra of DBP and HDBP, propitious to photopolymerization under a commercial mercury UV bulb are centered at 345 and 335 nm, respectively. HDBP has higher extinction coefficient than DBP, but lower photoinitiating efficiency. Their photoinitiating performances for EB605, a bisphenol A epoxy acrylate with 40%（mass fraction） tripropyleneglycol diacrylate （TPGDA）, resin consisting of bisphenol A epoxy acrylate and tripropyleneglycol diacrylate in the presence of triethanolamine as a coinitiator were investigated by photo-differential scanning calorimetry（photo-DSC）. DBP initiates the curing of acrylate more efficiently than HDBP, showing higher photopolymerization rate and unsaturation conversion, resulted from the poor compatibility of HDBP with the resin. The photoinitiating activity of DBP to epoxy acrylate resin is even higher than that of BP at lower loadings.

关键词： Macromolecular photoinitiator Benzophenone derivative Photopolymerization

Cure Kinetics of DGEBA with Hyperbranched Poly(3-hydroxyphenyl) Phosphate as Curing Agent Studied by Non-isothermal DSC

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Chemical Research in Chinese Universities 2006年第1期22卷 118-122页

作者： YAO Liang DENG Jing QU Bao-jun shi wen-fang State Key Laboratory of Fire Science Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 P. R. China

The cure kinetics of diglycidyl ether of bisphenol A （DGEBA） with hyperbranched poly （3-hydroxyphenyl） phosphate（HHPP） as the curing agent was investigated by means of non-isothermal differential scanning calorimetry （DSC） at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene（DHB） as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model（Sestak-Berggren equation） is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.

关键词： Hyperbranched polyphosphate Cure kinetics Epoxy resin Non-isothermal DSC

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植硅体释光信号特征及其对测年应用的启示

地震地质 2024年第1期46卷 101-116页

作者：李兆宁尹金辉杨会丽石文芳郑勇刚中国地震局地质研究所地震动力学国家重点实验室北京100029

中国西部青藏高原等地区往往缺乏可供AMS^(14)C测年的炭屑、植物残体等物质,开展传统的^(14)C测年有一定难度。然而,这些地区的现代地表常生长着大量草本植物,在其第四纪沉积物中均发现了丰富的植硅体。探索新的植硅体测年技术流程,可... 详细信息

中国西部青藏高原等地区往往缺乏可供AMS^(14)C测年的炭屑、植物残体等物质,开展传统的^(14)C测年有一定难度。然而,这些地区的现代地表常生长着大量草本植物,在其第四纪沉积物中均发现了丰富的植硅体。探索新的植硅体测年技术流程,可为中国西部地区的第四纪沉积物提供新的有效测年途径。植硅体以其自身的广泛分布性、结构稳定性和保存完整性,在测年应用中具有特殊优势,尤其是植硅体碳可用于^(14)C测年。然而,植硅体碳的^(14)C年龄存在高估问题,这可能是由于前处理过程中的快速氧化作用和高温作用破坏了其结构的稳定性和封闭性,需依据其化学组成和某些物理性质变化识别其结构在高温环境下的细微改变。植硅体作为特殊的非晶质含水SiO_(2),其热释光(Thermoluminescence,TL)与光释光(Optically stimulated luminescence,OSL)信号具有测年潜力,可作为直接比对和替代植硅体^(14)C测年法的另一测年手段,同时其释光性质变化可能对识别其物理结构变化具有参考价值。文中以从干稻草中提取的现代植硅体样品为例,对其进行了一系列条件实验,从而确定了植硅体OSL与ITL_(165)信号的具体测试流程,并进行了不同给定剂量的剂量恢复实验,以探讨其剂量-信号的响应关系及测试流程的可行性和可靠性。结果表明,天然植硅体颗粒存在稳定且易晒退的OSL信号,在较高给定剂量(850Gy)的条件下植硅体存在较显著且稳定的_(165)℃TL峰,OSL信号与ITL_(165)信号均有潜力应用于测年研究,但需要已知年龄的样品进行检验。与此同时,不同退火温度加热后的ITL_(500)曲线具有识别植硅体释光性质和物理结构变化的潜力,退火温度升高至300~350℃时植硅体的结构开始发生改变,至约600℃时已发生不可逆的结构改变且逐渐敏化。这也意味着在提取植硅体的过程中应尽可能使用湿式氧化法而非干灰化法,以避免植硅体的结构封闭性遭受破坏,从而造成植硅体碳的AMS^(14)C年龄被高估。

关键词：植硅体光释光信号等温热释光植硅体碳退火实验

Photopolymerization of Dendritic Acrylated Aromatic/Aliphatic Polyesters and Properties of Their Cured Films

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Chemical Research in Chinese Universities 2002年第3期18卷 354-357页

作者： XU Gang LIANG Hong-bo shi wen-fang BAO Jin-wen State Key Laboratory of Fire Science and Department of Applied Chemistry University of Science and Technology of ChinaHefei 230026China Institute of Aeronautical Materials Beijing 100095

The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.

关键词： Dendritic polyester Radiation curing Photopolymerization kinetics Thermal mechanical property

Closed-form expressions for outage probability of decode-and-forward relaying over Nakagami-m fading channels

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The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 72-75页

作者： CHUAI Gang LI Xiu-xin LIU Sheng HU Yang shi fang-wen Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China School of Network Education Beijing University of Posts and Telecommunications Beijing 100876 China

In this article, an exact closed-form expression is derived for outage probability of decode-and-forward （DF） cooperative communications over independent identically distributed Nakagami-m fading channels. Simulation results verify that the theoretical expressions for the outage probability are correct. The optimal power allocation based on the derived outage probability is also studied.

关键词： decode-and-forward Nakagami-m fading ,outage probability optimal power allocation

Aboveground biomass stocks of species-rich natural forests in southern China are influenced by stand structural attributes,species richness and precipitation

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Plant Diversity 2024年第4期46卷 530-536页

作者： wen-Hao Zeng shi-Dan Zhu Ying-Hua Luo Wei shi Yong-Qiang Wang Kun-fang Cao State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources College of ForestryGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China School of Life SciencesGuizhou Normal UniversityHuaxi College TownGui'an DistrictGuiyang 550025China

Forests,the largest terrestrial carbon sinks,play an important role in carbon sequestration and climate change *** forest attributes and environmental factors have been shown to impact aboveground biomass,their influence on biomass stocks in species-rich forests in southern China,a biodiversity hotspot,has rarely been *** this study,we characterized the effects of environmental factors,forest structure,and species diversity on aboveground biomass stocks of 30 plots(1 ha each) in natural forests located within seven nature reserves distributed across subtropical and marginal tropical zones in Guangxi,*** results indicate that forest aboveground biomass stocks in this region are lower than those in mature tropical and subtropical forests in other ***,we found that aboveground biomass was positively correlated with stand age,mean annual precipitation,elevation,structural attributes and species richness,although not with species *** we compared stands with the same basal area,we found that aboveground biomass stock was higher in communities with a higher coefficient of variation of diameter at breast *** findings highlight the importance of maintaining forest structural diversity and species richness to promote aboveground biomass accumulation and reveal the potential impacts of precipitation changes resulting from climate warming on the ecosystem services of subtropical and northern tropical forests in ***,many natural forests in southern China are not fully ***,their continued growth will increase their carbon storage over time.

关键词： Subtropical forest Marginal tropical forest Aboveground biomass Species diversity Forest structural attribute Environment factor