Abstract The novel shish-kebab-type liquid crystalline poly（p-phenylene）s were synthesized through Suzuki coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer 1） and 1,4-benzenedibo...Abstract The novel shish-kebab-type liquid crystalline poly（p-phenylene）s were synthesized through Suzuki coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer 1） and 1,4-benzenediboronic acid bistrimethylene cyclic ester （monomer 2）. Their structure and properties were characterized by GPC, DSC, X-ray diffraction and polarizing optical microscope （POM）. It was found that the polymers turned to liquid crystalline phase above their melting point. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The mesophase was identified by X-ray diffraction method. The polymers could dissolve in common organic solvents and show strong blue fluorescence. The maximum absorption bands of polymers prepared from annealed films have large red-shift due to the spontaneous orientation of the liquid crystalline side chains. The same phenomena were also observed in the fluorescence spectra.展开更多
Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tribu...Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tributylstannyl） ethylene （monomer 2）. The polymers with alkoxy groups are soluble in common organic solvents and exhibit blue fluorescence. Both the cast film and the annealed film have large red-shifts in fluorescence spectra and show yellow fluorescence. The polymers with CN and NO2 groups show poor solubility and green fluorescence. All the polymers possess liquid crystalline smectic phases. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The polymers are easily aligned under a magnetic field of 10 Tesla. It is found that the conjugated backbone and LC side chain are aligned perpendicular and parallel to the magnetic field, respectively. The polymers show optical dichroism in fluorescence spectra, suggesting that they are available for advance materials with linear optical polarization.展开更多
A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray di...A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.展开更多
For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment...For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment procedure using supercritical carbon dioxide(sc CO_(2))was carried out for oriented ultrahigh molecular weight polyethylene(UHMWPE) films, which provided special conditions for the crystallization of dissolved UHMWPE macromolecules on the surface of oriented UHMWPE crystals. The prepared porous materials were investigated by scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). The particularity of the obtained porous shish-kebab is the absence of the amorphous phase between lamellar crystals(kebabs). The obtained pores had an oval shape, and they were oriented in the orientation direction of the UHMWPE macromolecules. The pore size ranged from 0.05 μm to 4 μm. Controlling the conditions for the crystallization of the UHMWPE macromolecules using supercritical CO_(2) gives the possibility to control the size of both lamellar disks and pores formed.展开更多
介绍了指挥控制(command and control,C2)组织和C2组织结构,讨论了C2组织结构的适应性设计问题。分析了组织结构适应性的代价计算,主要由两个方面决定:一个是结构重构代价;另一个是组织性能代价。通过扩展基于粒度计算的组织结构设计方...介绍了指挥控制(command and control,C2)组织和C2组织结构,讨论了C2组织结构的适应性设计问题。分析了组织结构适应性的代价计算,主要由两个方面决定:一个是结构重构代价;另一个是组织性能代价。通过扩展基于粒度计算的组织结构设计方法,提出了组织结构的适应性设计方法,设计过程包括三个阶段:任务集和平台集粒化阶段、粒内规划阶段和决策分层阶段。给出了基于遗传算法的平台集粒化方法。案例分析表明本文的方法具有较好的性能。展开更多
基金This work was supported by China Scholarship Council and Grant-in-Aids for Scientific Research from Ministry of Education, Culture and Science of Japan.
文摘Abstract The novel shish-kebab-type liquid crystalline poly（p-phenylene）s were synthesized through Suzuki coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer 1） and 1,4-benzenediboronic acid bistrimethylene cyclic ester （monomer 2）. Their structure and properties were characterized by GPC, DSC, X-ray diffraction and polarizing optical microscope （POM）. It was found that the polymers turned to liquid crystalline phase above their melting point. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The mesophase was identified by X-ray diffraction method. The polymers could dissolve in common organic solvents and show strong blue fluorescence. The maximum absorption bands of polymers prepared from annealed films have large red-shift due to the spontaneous orientation of the liquid crystalline side chains. The same phenomena were also observed in the fluorescence spectra.
基金This work was supported by the China Scholarship Council and the Grant-in-Aids for Scientific Research from Ministry of Education, Culture, Sports, Science and Technology, Japan.
文摘Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tributylstannyl） ethylene （monomer 2）. The polymers with alkoxy groups are soluble in common organic solvents and exhibit blue fluorescence. Both the cast film and the annealed film have large red-shifts in fluorescence spectra and show yellow fluorescence. The polymers with CN and NO2 groups show poor solubility and green fluorescence. All the polymers possess liquid crystalline smectic phases. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The polymers are easily aligned under a magnetic field of 10 Tesla. It is found that the conjugated backbone and LC side chain are aligned perpendicular and parallel to the magnetic field, respectively. The polymers show optical dichroism in fluorescence spectra, suggesting that they are available for advance materials with linear optical polarization.
基金This work was supported by the National Natural Science Foundation of China (No. 29674025) and the Natural Science Foundation of Henan Province.
文摘A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.
基金financially supported by the Academic leadership program Priority 2030 proposed by Federal State Autonomous Educational Institution of Higher Education I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University)The preparation and modification of UHMWPE samples were financially supported by the Russian Science Foundation (No.18-13-00145)SEM investigation was supported by the State Assignment (No.0090-2019-0002, IPAC RAS)。
文摘For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment procedure using supercritical carbon dioxide(sc CO_(2))was carried out for oriented ultrahigh molecular weight polyethylene(UHMWPE) films, which provided special conditions for the crystallization of dissolved UHMWPE macromolecules on the surface of oriented UHMWPE crystals. The prepared porous materials were investigated by scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). The particularity of the obtained porous shish-kebab is the absence of the amorphous phase between lamellar crystals(kebabs). The obtained pores had an oval shape, and they were oriented in the orientation direction of the UHMWPE macromolecules. The pore size ranged from 0.05 μm to 4 μm. Controlling the conditions for the crystallization of the UHMWPE macromolecules using supercritical CO_(2) gives the possibility to control the size of both lamellar disks and pores formed.
文摘介绍了指挥控制(command and control,C2)组织和C2组织结构,讨论了C2组织结构的适应性设计问题。分析了组织结构适应性的代价计算,主要由两个方面决定:一个是结构重构代价;另一个是组织性能代价。通过扩展基于粒度计算的组织结构设计方法,提出了组织结构的适应性设计方法,设计过程包括三个阶段:任务集和平台集粒化阶段、粒内规划阶段和决策分层阶段。给出了基于遗传算法的平台集粒化方法。案例分析表明本文的方法具有较好的性能。
