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試論章草之“正体化”
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作者 林秋秋 《书法研究》 CSSCI 北大核心 2024年第5期153-165,197,198,共15页
東漢晚期,經歷了兩次黨錮之禍的知識階層從群體認同價值標準轉向追求個人精神的獨立與自由,意味着漢代儒家大一統思想體系解體,新的思想體系開始建立。反映在書法思想史上,以張芝属代表的敦煌草書流派崛起,追求草書個性,并創造性地推動... 東漢晚期,經歷了兩次黨錮之禍的知識階層從群體認同價值標準轉向追求個人精神的獨立與自由,意味着漢代儒家大一統思想體系解體,新的思想體系開始建立。反映在書法思想史上,以張芝属代表的敦煌草書流派崛起,追求草書個性,并創造性地推動了章草“正體化”的產生。本文圍繞章草“正體化”,將其分馬兩個階段,并從章草符合士人階層追求個人精神獨立與自由的心理、草書尺牘風尚及文人草書家.的整理兩個方面論述此過程的成因。章草“正體化”過程促進了魏晋草書系統的成熟,奠定了中國草書中主體自由與審美超越的審美核心。 展开更多
关键词 章草 正體 張芝 審美自覺
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清代中叶书法创作的正体化倾向
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作者 孙学峰 《美术观察》 北大核心 2007年第10期102-107,共6页
受朝廷以"政统"兼并"道统"的诸多措施和理学本身的影响,清代中叶士人形成正体化的书写习惯和审美观念,因而,书法创作也呈现出正体化的倾向。这种倾向不但表现为楷书和篆隶等正体文字书法的兴盛;还表现为文字构形与... 受朝廷以"政统"兼并"道统"的诸多措施和理学本身的影响,清代中叶士人形成正体化的书写习惯和审美观念,因而,书法创作也呈现出正体化的倾向。这种倾向不但表现为楷书和篆隶等正体文字书法的兴盛;还表现为文字构形与朝廷规定的标准字书的一致,绝少异体、别体;更表现为点画用笔的踏实沉稳、起收动作的完整,单字体势的完美和端庄,字与字之间缺少意态的呼应,章法排布的大小匀称甚至界格整齐等。作为经过严格书写训练的书法创作主体,士人的这一倾向构成清代中叶书法的时代风貌。 展开更多
关键词 清代中叶 士人 书法创作 正体化
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清代中叶书法创作的正体化倾向
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作者 孙学峰 《书法研究》 北大核心 2007年第6期101-112,共12页
受清朝廷以“政统”兼并“道统”的诸多措施和理学本身的影响,清代中叶士人形成正体化的书写习惯和审美观念,因而,书法创作也呈现出正体化的倾向。这种倾向不但表现为楷书和篆隶等正体文字书法的兴盛;还表现为文字构形与朝廷规定的... 受清朝廷以“政统”兼并“道统”的诸多措施和理学本身的影响,清代中叶士人形成正体化的书写习惯和审美观念,因而,书法创作也呈现出正体化的倾向。这种倾向不但表现为楷书和篆隶等正体文字书法的兴盛;还表现为文字构形与朝廷规定的标准字书的一致,绝少异体、别体;更表现为点画用笔的踏实沉稳、起收动作的完整,单字体势的完美和端庄,字与字之间缺少意态的呼应,章法排布的大小匀称甚至界格整齐等。作为经过严格书写训练的书法创作主体,士人的这一倾向构成清代中叶书法的时代风貌。 展开更多
关键词 清代中叶 士人 书法 正体化
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Optimization and Testing for PCR System of Rice by Orthogonal Design 被引量:8
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作者 程芳艳 李春光 +5 位作者 刘永巍 孟巧霞 张景龙 宋冬明 刘华招 孟昭河 《Agricultural Science & Technology》 CAS 2010年第2期61-64,共4页
[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves ... [Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves by CTAB method as the template,PCR system was optimized by L16(45)orthogonal design.[Result] Clear bands were amplified from 16 different combinations,but the amplification effects and yields had difference.The most economic and applicable system was as follows:20 ng DNA template,150 μmol/L dNT... 展开更多
关键词 RICE PCR system optimization Orthogonal design Dominant molecular markers testing
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Optimization of PCR Reaction System for Random Single-strand DNA Pool in SELEX Technology
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作者 曹立亭 许李丽 +2 位作者 万向 王秋菊 马跃 《Agricultural Science & Technology》 CAS 2012年第2期273-275,329,共4页
[Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16(45) orthogonal experimental design was adopted for optimization of five important fac... [Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16(45) orthogonal experimental design was adopted for optimization of five important factors affecting PCR reaction system for random single-stranded DNA pool including Mg2+ concentration, dNTP concentration, amount of Taq DNA polymerase, primer concentration and amount of random single-stranded DNA pool at four levels. Meanwhile, the annealing temperature and number of PCR reaction cycles were optimized to establish the optimal reaction system and PCR procedure. [Result] The optimal combination of PCR reaction system for random ssDNA pool was obtained, with a total system volume of 20 μl containing 2.0 μl of 10 × Buffer, 0.5 ng of random ssDNA pool, 2.5 mmol/L Mg2+, 0.25 mmol/L dNTP Mixture, 0.6 μmol/L upstream and downstream primers and 1.5 U of Taq DNA polymerase; the optimal annealing temperature was 68 ℃ and the optimal number of cycles was 12. Under the above conditions, clear and stable bands with high specificity for random ssDNA pool were amplified. [Conclusion] This study laid the foundation for selection of parameters with higher specificity in SELEX technology. 展开更多
关键词 Random single-stranded DNA pool Orthogonal experimental design Polymerase chain reaction System optimization
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Optimization of RAPD-PCR Reaction System for Glycyrrhiza uralensis Based on Orthogonal Design 被引量:5
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作者 张增福 董建力 李明 《Agricultural Science & Technology》 CAS 2011年第10期1427-1429,共3页
[Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors(dNTPs,primers,Taq pol... [Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors(dNTPs,primers,Taq polymerase and DNA template) in PCR reaction system.[Result] The optimal reaction system obtained by orthogonal design was 25 μl in total volume,containing 2.5 μl of 10×PCR buffer solution(include MgCl2),2.5 μl of 10 mmol/L dNTPs,2 μl(100 ng) of DNA template,2 μl of 10 μmol/L primers,0.4 μl(5 U) of Taq polymerase;the optimum annealing temperature was 34 ℃.[Conclusion] Orthogonal design was an effective method for the optimization of RAPD-PCR reaction system for G.uralensis. 展开更多
关键词 Glycyrrhiza uralensis DNA RAPD-PCR Reaction system OPTIMIZATION Orthogonal design
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RESEARCH ON MATRIX CRACK EVOLUTION OF CROSS-PLY CERAMIC MATRIX COMPOSITE 被引量:1
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作者 杨福树 孙志刚 +1 位作者 李龙彪 宋迎东 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第1期112-119,共8页
The matrix crack evolution of cross-ply ceramic matrix composites under uniaxial tensile loading is investigated using the energy balance method.Under tensile loading,the cross-ply ceramic matrix composites have five ... The matrix crack evolution of cross-ply ceramic matrix composites under uniaxial tensile loading is investigated using the energy balance method.Under tensile loading,the cross-ply ceramic matrix composites have five damage modes.The cracking mode 3 contains transverse cracking,matrix cracking and fiber/matrix interface debonding.The cracking mode 5 only contains matrix cracking and fiber/matrix interface debonding.The cracking stress of modes 3 and 5 appearing between existing transverse cracks is determined.And the multiple matrix crack evolution of mode 3 is determined.The effects of ply thickness,fiber volume fraction,interface shear stress and interface debonding energy on the cracking stress and matrix crack evolution are analyzed.Results indicate that the cracking mode 3 is more likely to appear between transverse cracks for the SiC/CAS material. 展开更多
关键词 ceramic matrix composites CROSS-PLY matrix crack evolution energy balance approach
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Renormalization Group Theory and Its Application to Thermally-Induced Turbulence 被引量:1
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作者 CAOYi-Gang W.K.Chow 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第4期599-604,共6页
Renormalization group theory applied to turbulence will be reviewed in this article.Techniques associated are used for analyzing thermally-induced turbulence.Transport properties such as effective viscosity and therma... Renormalization group theory applied to turbulence will be reviewed in this article.Techniques associated are used for analyzing thermally-induced turbulence.Transport properties such as effective viscosity and thermal diffusivity are derived. 展开更多
关键词 renormalization group TURBULENCE
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Deformation and densification behavior of discrete media filled thin-walled tubes during forward extrusion 被引量:1
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作者 Tong WEN Qing LIU +2 位作者 Qian HUANG Wen-xue OU Jian-qing FENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第8期2162-2169,共8页
Discrete media filled thin-walled hollow profiles are frequently used as integer structures for special purpose, e.g., in certain materials processing or architectural components. To understand the deformation of such... Discrete media filled thin-walled hollow profiles are frequently used as integer structures for special purpose, e.g., in certain materials processing or architectural components. To understand the deformation of such composite structures which is a complicate mechanics process, involving coupled elastic-plastic deformation of dense metal, compaction of particle and interaction between the filler and the wall, the forward extrusion of Al 6061 tubes filled with various particles was studied. The analysis regarding internal volume variation of round tubes during forward extrusion indicates that with the diameter reduction the volume of tubes decreases commonly. The cavity shrinkage brings about triaxial pressure on the filler, resulted in compaction and densification of it. Loose powders filling leads to higher extrusion load. Due to dissimilar migration behaviors of the particles, the load?stroke curves of the tubes filled with fine powders and coarse balls are quite different. Small Lankford value of the tube wall material leads to higher hydrostatic pressure of the filler and then more powders are compacted. 展开更多
关键词 tube forward extrusion POWDER deformation behavior DENSIFICATION
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Transfer and Reaction Performances of Selective Catalytic Reduction of NzO with CO over Monolith Catalysts 被引量:3
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作者 代成娜 雷志刚 +2 位作者 王玉丽 张润铎 陈标华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第8期835-843,共9页
This work tries to identify the relationship between geometric configuration of monolith catalysts, and transfer and reaction performances for selective catalytic reduction of N2O with CO. Monolith catalysts with five... This work tries to identify the relationship between geometric configuration of monolith catalysts, and transfer and reaction performances for selective catalytic reduction of N2O with CO. Monolith catalysts with five different channel shapes (circle, regular triangle, rectangle, square and hexagon), was investigated to make a comprehensive comparison of their pressure drop, heat transfer Nu number, mass transfer Sh number and N2O conversion. It was found that monolith catalysts have a much lower pressure drop than that of traditional packed bed, and for monolith catalysts with different channel shapes, pressure drop decreases in the order of regular triangle > rectangle > square > hexagon > circle. The order of Nu is in regular triangle > rectangle ≈ square > hexagon > circle, similar to that of Sh. N2O conversion follows the order of regular triangle > rectangular ≈ square ≈ circle > hexagon. The results indicate that chemical reaction including internal diffusion is the controlling step in the selective catalytic reduction of N2O removal with CO. In addition, channel size and gas velocity also have influence on N2O conversion and pressure drop. 展开更多
关键词 selective catalytic reduction N2O conversion momentum transfer heat transfer mass transfer monolith catalysts mathematical modeling
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Preparation and Characterization of Nanosized Al-MCM-41 Using Different Silica Sources
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作者 I.A. Makhlid R.M. Mohamed +2 位作者 A.A. EI-Midany I.A. Ibrahim E.H. EI-Mossalamy 《Journal of Environmental Science and Engineering》 2010年第4期21-28,共8页
Silica sources influence different aspects of Al-MCM-41 product. The crystallinity of nanosized Al-MCM-41 zeolites prepared crystallization and lead to change in the properties of the final from precursors mixtures co... Silica sources influence different aspects of Al-MCM-41 product. The crystallinity of nanosized Al-MCM-41 zeolites prepared crystallization and lead to change in the properties of the final from precursors mixtures containing different silica sources, e.g. tetraethylorthosilicate (TEOS), colloidal silica (CS), silicic acid (SA) and fumed silica (FS) have been studied. The produced samples are investigated using XRD, SEM, FT-IR, pyridine adsorption and N2 physisorption. XRD results show that the products obtained from different silica sources are in Al-MCM-41 phase. SEM results show that silica sources influence the produced Al-MCM-41 shape. Using silicic acid leads to formation of spherical crystals, TEOS gives cubical crystals, colloidal silica forms spherical crystals with smaller aggregated, and fumed silica gives rounded crystals. N2 physisorption results show that silica sources influence pore-diameter and pore-volume of the produced Al-MCM-41 ; the pore diameter of the produced Al-MCM-41 in case of colloidal silica, TEOS, fumed silica, and silicic acid are 12, 20, 15, and 17A respectively. Also, the pore volume of the produced AI-MCM-41 in case of colloidal silica, TEOS, fumed silica and silicic acid are 0.78, 0.71, 0.76, and 0.8 cm^3/gm, respectively. 展开更多
关键词 AL-MCM-41 PREPARATION silica sources Physico-chemical properties.
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Preparation of Nano-Particles (Pb,La)TiO_3 Thin Films by Liquid Source Misted Chemical Deposition
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作者 张之圣 曾建平 李小图 《Transactions of Tianjin University》 EI CAS 2004年第1期59-62,共4页
Nano particles lanthanum modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO 2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at v... Nano particles lanthanum modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO 2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h. 展开更多
关键词 liquid source misted chemical deposition (LSMCD) nano particle (Pb La)TiO 3 thin films XRD SEM
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Orthogonal array design for the optimization of stripping Sr(Ⅱ) from ionic liquids using supercritical CO2
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作者 Tao Yang Jing Fu +1 位作者 Qingde Chen Xinghai Shen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第1期26-31,共6页
The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(s... The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(sc-CO_2).Hexafluoroacetylacetone(HFAA)-acetonitrile was found to be an excellent modifier of sc-CO_2 to enhance the stripping efficiency.In the orthogonal array design(OAD),OA_(25)(5~5)matrix was employed to optimize the stripping of Sr(Ⅱ) from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors:temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(Ⅱ) were optimized.The effects of these parameters were treated by the analysis of variance(ANOVA).The results showed that Sr(II) could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^(-1) HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS. 展开更多
关键词 Supercritical CO2 stripping Ionic liquid Strontium Orthogonal array design
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王者之风:《集王圣教序》与唐代书法史一个断层的重建 被引量:1
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作者 李慧斌 《中国书法》 CSSCI 2019年第20期4-10,共7页
如何看待唐太宗尊王后的一系列书法发展问题是唐代书法史研究很重要的课题。而这其中最为重要的就是《集王圣教序》的刊刻以及刊刻后成为传世王羲之书法作品之外创造出的新经典,对唐代行书的发展产生了广泛而深远的影响。本文通过对大... 如何看待唐太宗尊王后的一系列书法发展问题是唐代书法史研究很重要的课题。而这其中最为重要的就是《集王圣教序》的刊刻以及刊刻后成为传世王羲之书法作品之外创造出的新经典,对唐代行书的发展产生了广泛而深远的影响。本文通过对大量新出土唐代碑志书迹的整理和研究,对这种影响展开具体研究。借助在时间序列性上具有代表性的书迹,初步勾勒出了一个受"王体"行书特别是《集王圣教序》影响的书法史发展脉络。通过分期研究和大量作品的印证,对以往唐代书法史研究中以《集王圣教序》为发展脉络所出现的断层进行了重构,并借此初步建立起了唐代以《集王圣教序》为主导的书法史体系和框架。 展开更多
关键词 集王圣教序 唐代书法史 断层 院体 墓志 正体化
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Global convergence of a solution to p-Ginzburg-Landau type equations
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作者 雷雨田 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2005年第3期381-390,共10页
The author studies the global convergence of a solution of p-Ginzburg-Landau equations when the parameter tends to zero. The convergence is in C^α sense, which is derived by establishing a uniform gradient estimate f... The author studies the global convergence of a solution of p-Ginzburg-Landau equations when the parameter tends to zero. The convergence is in C^α sense, which is derived by establishing a uniform gradient estimate for some solution of a regularized p-Ginzburg-Landau equations. 展开更多
关键词 global convergence regularizable solution p-energy minimizer.
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Electron-plasmon interaction induced plasmonic-polaron band replication in epitaxial perovskite SrIrO_(3) films 被引量:1
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作者 Zhengtai Liu Wanling Liu +12 位作者 Ruixiang Zhou Songhua Cai Yekai Song Qi Yao Xiangle Lu Jishan Liu Zhonghao Liu Zhen Wang Yi Zheng Peng Wang Zhi Liu Gang Li Dawei Shen 《Science Bulletin》 SCIE EI CSCD 2021年第5期433-440,M0003,共9页
Electron-boson interaction is fundamental to a thorough understanding of various exotic properties emerging in many-body physics. In photoemission spectroscopy, photoelectron emission due to photon absorption would tr... Electron-boson interaction is fundamental to a thorough understanding of various exotic properties emerging in many-body physics. In photoemission spectroscopy, photoelectron emission due to photon absorption would trigger diverse collective excitations in solids, including the emergence of phonons,magnons, electron-hole pairs, and plasmons, which naturally provides a reliable pathway to study electron-boson couplings. While fingerprints of electron–phonon/-magnon interactions in this state-ofthe-art technique have been well investigated, much less is known about electron-plasmon coupling,and direct observation of the band renormalization solely due to electron-plasmon interactions is extremely challenging. Here by utilizing integrated oxide molecular-beam epitaxy and angle-resolved photoemission spectroscopy, we discover the long sought-after pure electron-plasmon couplinginduced low-lying plasmonic-polaron replica bands in epitaxial semimetallic SrIrO_(3) films, in which the characteristic low carrier concentration and narrow bandwidth combine to provide a unique platform where the electron-plasmon interaction can be investigated kinematically in photoemission spectroscopy. This finding enriches the forms of electron band normalization on collective modes in solids and demonstrates that, to obtain a complete understanding of the quasiparticle dynamics in 5 d electron systems, the electron-plasmon interaction should be considered on equal footing with the acknowledged electron–electron interaction and spin–orbit coupling. 展开更多
关键词 perovskite SrIrO_(3) 5d electron systems Electron-plasmon interaction Replica bands
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Orthogonal array optimization of ionic liquid based dispersive liquid-liquid microextraction for toxic anilines in foods 被引量:2
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作者 YANG Peng REN HaiXia +2 位作者 WEI Zheng LIU Xia JIANG ShengXiang 《Science China Chemistry》 SCIE EI CAS 2012年第2期277-284,共8页
A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction (DLLME) combining with high performance liquid chromatography (HPLC) was developed for the analysis of four toxic anilines i... A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction (DLLME) combining with high performance liquid chromatography (HPLC) was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design (OAD) with OA25(54) matrix. Analysis of variance (ANOVA) and percent contribution (PC) were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity (r2 〉 0.99) over the studied range (50-1000 ng g-l) for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections (LODs) and limit of quantitations (LOQs) ranged be- tween 10-15 ng g-1 and 30--45 ng g-1. 展开更多
关键词 ANILINE ionic liquid dispersive liquid-liquid microextraction orthogonal array optimization
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Lattice-parameter effects on diffracted transmission of GaN two-dimensional square-lattice photonic crystals 被引量:1
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作者 XIONG Chang ZHANG Bei +2 位作者 KANG XiangNing FU XingXing ZHANG GuoYi 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期23-27,共5页
The lattice-parameter effects on the diffracted transmission of GaN square-lattice photonic crystals (2PhC) at the wavelength of 460 nm were studied by using a rigorous coupled wave analysis (RCWA). The impacts of... The lattice-parameter effects on the diffracted transmission of GaN square-lattice photonic crystals (2PhC) at the wavelength of 460 nm were studied by using a rigorous coupled wave analysis (RCWA). The impacts of lattice parameters on the diffracted transmission are calculated in the ranges for lattice pitch from 100 nm to 2000 nm, fill factor from 0.1 to 0.9 and grat- ing height from 100 nm to 1000 rim, respectively. Our simulation results confirm that the lattice pitch is the dominant factor of the diffraction. It determines how many orders of diffraction occur by the 2PhCs. The larger the lattice pitch, the higher the diffraction orders come into play. Moreover, besides the first-order Bragg diffraction, higher diffraction orders from large pitches of PhCs are also beneficial to the light extraction improvement. The higher enhancement factors of the integrated transmission were obtained from a wide range of pitches with micro-scale GaN 2PhCs. Three different diffraction mechanisms through wave vector analysis were used to discuss the simulation results. 展开更多
关键词 GAN photonic crystal DIFFRACTION
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Anionic polymerization of fluorine-substituted phenyl methacrylates
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作者 Bin Li Pan Zhou +2 位作者 Yuefei Chen Biao Jiang Hongping Zhu 《Science China Chemistry》 SCIE EI CAS CSCD 2015年第1期107-113,共7页
Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C(CH3)C(O)OC6H4F-4 (M^1a), H2... Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C(CH3)C(O)OC6H4F-4 (M^1a), H2C=C(CH3)C(O)OC6H4F-3 (M^1b), HEC=C(CH3)C(O)OC6H3F2-2,4 (M^2), H2C=C(CH3)C(O)OC6H2F3-2,3,4 (M^3), H2C=C(CH3)C(O)OC6HF4-2,3,5,6 (M^4), and H2C=C(CH3)C(O)OC6F5 (M^5) were synthesized and characterized. Initially, the polymerization was carded out on the monomer M^1a by using nBuLi, tBuLi, and KH as the respective catalysts; this approach produced the polymers in yields of 12%-50%, but with lower molecular weights. Similar results were obtained by using tBuLi for catalytically polymerizing the other five monomers. By introducing a co-catalyst MeAl(BHT)2, the catalysts Nail, LiH, and tBuOLi each were tested to polymerize M^1a, which gave the polymers in very low yields (3%-7%). Polymer yields of 13%-27% were obtained by each of the catalysts LiAlH4, nBuLi, PhLi, and tBuLi in connection with MeAI(BHT)2, but a better yield (61%) was achieved with KH/MeAl(BHT)2. The KH/MeAl(BHT)2 catalyst system was further employed to polymerize M^1b and M^2, which afforded respective polymer yields of 12%-63% and 10%-53%, depending on the molar ratios of KH:MeAl(BHT)2 as well as on the monomer concentrations. All of the polymers produced were syndiotactically rich in structure, as indicated by either ^1H or ^19F NMR data. The polymerization mechanism by the combined catalyst system is proposed. 展开更多
关键词 fluorophenyl methacrylates the combined catalyst system anionic polymerization syndiotactic polymer ^1H and ^19F NMR data
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A new barium-containing alkali metal silicate fluoride NaBa3Si2O7F with deep-UV optical property 被引量:3
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作者 Zhaohong Miao Yun Yang +3 位作者 Zhonglei Wei Zhihua Yang Tushagu Abudouwufu Shilie Pan 《Science China Materials》 SCIE EI CSCD 2019年第10期1454-1462,共9页
A new silicate fluoride,NaBa3 Si207 F,has been successfully synthesized by a high-temperature solution method.It crystallizes in the orthorhombic space group Cmcm(No.63).NaBa3 Si2 O7 F is the first barium-containing a... A new silicate fluoride,NaBa3 Si207 F,has been successfully synthesized by a high-temperature solution method.It crystallizes in the orthorhombic space group Cmcm(No.63).NaBa3 Si2 O7 F is the first barium-containing alkali metal silicate fluoride with the[NaO6]polyhedra,the[BaO8 F]polyhedra and isolated[Si2 O7]units.The optical characterizations indicate that NaBa3 Si2 O7 F possesses wide transparent window and available luminescence properties.To confirm the coordination surroundings of anionic groups and its thermostability,infrared spectroscopy and thermal behaviors were also analyzed,which proved the existence of tetrahedronly coordinated silicium atoms and the good stability of NaBa3 Si2 O7 F at high temperature.First-principles calculation was also implemented for better understanding the relationship between the structure of NaBa3 Si207 F and its property.Additionally,to further explore the structural novelty of NaBa3 Si2 O7 F,the comparison of the anionic structures was carried out in mixed alkali and alkaline-earth metal silicate fluorides.Interestingly,the result indicates the isolated[Si2 O7]dimer is rare among the above systems,which enriches the structural chemistry of silicate fluorides. 展开更多
关键词 silicate fluoride deep-ultraviolet transparent window structure-properties relationship structure comparison
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