http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
EXISTENCE OF PERIODIC SOLUTIONS OF A HIGHER ORDER DIFFERENCE SYSTEM
Hu, Ronghui,Huang, Lihong Korean Mathematical Society 2008 대한수학회지 Vol.45 No.2
By using critical point theorem, we study a higher order difference system, and obtain some new sufficient conditions ensuring the existence of periodic solutions for such a system.
Existence of periodic solutions of a higher order difference system
Ronghui Hu,Lihong Huang 대한수학회 2008 대한수학회지 Vol.45 No.2
By using critical point theorem, we study a higher order difference system, and obtain some new sufficient conditions ensuring the existence of periodic solutions for such a system By using critical point theorem, we study a higher order difference system, and obtain some new sufficient conditions ensuring the existence of periodic solutions for such a system
Enhancement of thermal stability and chemical reactivity of phenolic resin ameliorated by nanoSiO2
Yajun Guo,Lihong Hu,Puyou Jia,Baofang Zhang,Yonghong Zhou 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1
Phenolic resin has unsatisfactory thermal stability owing to the poor anti-oxidation property of methylene and phenol groups. To overcome this defect, a series of phenolic resin modified by nanoSiO2 based on the tetraethoxysilane (TEOS) was successfully prepared via sol-gel method using phenol as solvent. The effect of nanoSiO2 on the structures and properties of phenolic resin/foam was investigated. TGA and DTG indicated that the initial decomposition temperature of PR-0.5 (TEOS accounted for 0.5% of phenolic resin) was 41.8 oC higher than the neat PR-0. DSC revealed that the peak temperature presented a parabolic shape with the dosage of the TEOS, its maximal value resting on the PR-0.5. FT-IR and XRD demonstrated that chemical crosslink was reacted between PR and nanoSiO2 hydrolyzed by the TEOS, forming new chemical bands. Reactivity analysis illustrated that the free phenol content and the hydroxymethyl group content changed sharply in PF-0.5, implying it has highest reactivity.
Synthesis and characterization of glyceryl monooleate-based polyester
Puyou Jia,Caiying Bo,Lihong Hu,Yonghong Zhou 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.3
A unique biobased polyester poly(succinic acid-glyceryl monooleate) (PSAGMO) was synthesized andcharacterized from succinic acid (SA) and glyceryl monooleate (GMO). The polyester was characterized by gel permeationchromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic response spectroscopy(NMR). The polyester was used as the plasticizer of poly (vinyl chloride) (PVC). The mechanical propertiesand the thermodynamic properties of the blends were characterized. The TG-DTA data indicated that the thermal degradationtemperature (Td) of PVC blends plasticized with PSAGMO could increase from 249.3 oC to 255.6 oC. TheDMA showed that the glass transition temperature (Tg) of the PVC blends decreased from 49.5 oC to 35 oC. The mechanicalproperties indicated that the PSAGMO could decrease the tensile strength and increase the elongation at break ofthe PVC blends. This study may lead to the development of new type of PVC plasticizer based on renewable resource.
Puyou Jia,Meng Zhang,Lihong Hu,Yonghong Zhou 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3
Vegetable oil based plasticizers have potential use as nontoxic and sustainable plasticizer and as replacements for commonly used phthalate plasticizers. In this study, novel soybean oil based polyol esters (derived from glycerin or pentaerythritol, of which two were acetylated and two were additionally epoxidized) were synthesized and characterized with GPC, FT-IR and 1H NMR. Properties of poly (vinyl chloride) (PVC) plasticized with different soybean oil based polyol ester as main plasticizer were evaluated and compared to that of traditional plasticizers dioctyl phthalate (DOP) and epoxidized soybean oil (ESO). It has been proved that thermal stability of PVC blends could be improved by soybean oil based polyol ester plasticizers. Plasticizing effect of pentaerythritol derived soybean oil polyesters on PVC is better than that of DOP, ESO, and glycerin derived soybean oil polyesters. Tests of migration stability showed that with the increasing of the molecular weight, branching degree of molecular and ester bands of soybean oil based polyol ester, the migration stability was enhanced. This study may lead to the development of new type of PVC materials using soybean oil based polyol ester as main plasticizer.
Shulin Cai,Shuaishuai Hu,Jianming Wu,An Huang,Lihong Geng,Xiangfang Peng 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5
Cellulose-based fluorescent fibers were successfully fabricated by interfacial polyelectrolyte complexation (IPC)spinning, in which thioglycolic acid-modified CdTe quantum dots (QDs) were incorporated. The fibers exhibited differentfluorescent colors depending on different sizes of CdTe QDs. The IPC spinning process based on the progressive selfassemblyof negatively charged cellulose nanofibers (CNFs) and positively charged chitosan endowed the fibers highorientation degree. Together with the superior mechanical property of CNFs and the strong interfacial ionic bond andhydrogen bond interaction between CNFs and chitosan, the fluorescent fibers showed a high tensile strength above 689 MPaand toughness above 25 MJ/m3, which provided a guarantee for weaving the fluorescent fibers into textiles. With excellentoptical and mechanical performance, the resulting fluorescent fibers showed a promising potential as flexible wearable anticounterfeitingdevices, which the hard-to-see tag woven using the fluorescent fibers appeared clearly under 365 nmultraviolet light illumination. This paper would provide a new avenue for the preparation of high-performance environmentfriendlyfluorescent anti-counterfeiting textiles.
Puyou Jia,Guodong Feng,Caiying Bo,Lihong Hu,Xiaohui Yang,Liqiang Zhang,Meng Zhang,Yonghong Zhou 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.60 No.-
A composition of phosphaphenanthrene groups-containing castor-oil-based phosphate plasticizer (PGPP) was synthesized and characterized. Flame retardant PVC blends cooperated with different mass of PGPP were prepared. Flame retardancy of PVC blends were investigated with LOI, TGA, TGA-FTIR, TGA-MS and cone calorimeter. Flame retardant mechanism was also studied. The flame retardant performance of PGPP provides novel route for efficient use of vegetable oil and preparing advanced flame retardant PVC materials.
Guodong Feng,Puyou Jia,Liqiang Zhang,Lihong Hu,Meng Zhang,Yonghong Zhou 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.6
A novel flame-retardant plasticizer based on castor oil (FRC) was synthesized, and its potential application for polyvinyl chloride (PVC) was evaluated through the study of torque during melt processing, thermogravimetric analysis (TGA), limiting oxygen index instrument, scanning electron microscope (SEM) and mechanical tests. The results suggested that the FRC has a plasticizing effect in blends with PVC. The addition of FRC resulted in reduction of processing torque, good compatibility, improvement in thermal stability and efficient flame retardant. Torque reduction was observed (33.6%), indicating the reduction of viscosity and the improvement of process. The increase (31.9%) of LOI value indicated that incorporation of FRC system had obviously improved the flame retardant property of PVC blends. The excellent flame retardant properties were obtained by forming an isolation layer on the surface of PVC blends in the process of FRC burning. FRC could improve the thermal ability of PVC blends by enhancing the decomposition temperature of PVC. The performance in all properties of PVC products could be obtained by controlling the formula blends. Therefore, castor oil-based flame retardant plasticizers would appear suitable for a wide range of application.
Puyou Jia,Meng Zhang,Caiying Bo,Liqiang Zhang,Lihong Hu,Yonghong Zhou 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-
Epoxidized castor oil (ECO) and castor oil phosphate ester (COPE) were synthesized. Structure of twofunctionalized castor oil was characterized with FTIR and 1H NMR. Property of poly (vinyl chloride) PVCblends plasticized with ECO and (COPE) as secondary plasticizer was studied. The results indicated thatthermal stability of plasticized PVC blends was improved, LOI value of PVC blends cooperated with COPEcould reach 27.8%, flame retardant performance of COPE was put into effect by promoting polymercarbonization and forming a consolidated and thick flame retardant coating, which is effective toprohibit the heat flux and air incursion.