Showing papers in "Insulating Materials in 2011"
Journal Article•
TL;DR: In this paper, a viscous polyamic acid (PAA) solution was prepared by polycondensation reaction between fluorinated diamine II and pyromellitic dianhydride(PMDA) in polar aprotic organic solvent DMAc, and the corresponding polyimide(PI) film was also obtained by thermal imidization.
Abstract: A kind of viscous polyamic acid(PAA) solution was prepared by polycondensation reaction between fluorinated diamine II and pyromellitic dianhydride(PMDA) in polar aprotic organic solvent DMAc,and the corresponding polyimide(PI) film was also obtained by thermal imidization.The properties of the PI film were further studied,and compared with PI(PMDA-ODA).The experimental results show that the fluorinated diamine improves the transparency and solubility of PI and maintains an excellent thermal stability of PI.
7 citations
Journal Article•
TL;DR: For improving speed and accuracy of fast ellipse fitting algorithm for contact angle calculation, the influence of various factors on algorithm accuracy and real-time performance was analyzed by experiment as discussed by the authors.
Abstract: For improving speed and accuracy of fast ellipse fitting algorithm for contact angle calculation,the influence of various factors on algorithm accuracy and real-time performance was analyzed by experimentThe result indicates that: five fitting points is enoughThe selected points should be nearly uniform distributed around the globule edge,if selected points are concentrated then the error of contact angle calculation will increase badlyThe error of measurement will increase with the increase of noise,then five edge points should be selected,and the mean value of multiple calculations can be used to decrease error As for ellipse figure,circle fitting algorithm has good stability but still has large error,and the error will increase with the increase of eccentricity,the calculated value is less than the real valueTime for selecting edge point is the main cost when circle or ellipse algorithm is selected in which time consuming will increase with the increase of selected point number
3 citations
Journal Article•
TL;DR: In this paper, the development process of environmental friendly vacuum pressure impregnating (VPI) resin was introduced and the application of existing products and future development trends at home and abroad were analyzed.
Abstract: The development process of environmental friendly vacuum pressure impregnating(VPI) resin was introduced and the application of existing products and future development trends at home and abroad were analyzed.
2 citations
Journal Article•
TL;DR: In this paper, a kind of polyamide acid/carbon nano-tube hybrid liquid cement was fabricated by means of ultrasonic dispersion and in-situ polymerization, and the surface morphology of the film was characterized by SEM.
Abstract: A kind of polyamide acid/carbon nano-tube hybrid liquid cement was fabricated by means of ultrasonic dispersion and in-situ polymerization.Then the polyimide/carbon nano-tube hybrid film was prepared according to filming technology.The surface morphology of the film was characterized by SEM.And the effects of incorporation of carbon nano-tube on the electrical property were researched. The results show that with the increase of CNTs content,the dielectric strength decreases gradually and has a sharp drop when the doped content is close to 0.6%,the dielectric constant and dielectric loss factor increase obviously.With the rise of test frequency,the dielectric constant declines slowly and the dielectric loss factor increases.The corona resistance time of the hybrid film is longer than that of pure polyimide.When the doped content of MWNTs is near to 0.38%,the time of corona resistance reaches a maximum of 10.2 h.
1 citations
Journal Article•
TL;DR: In this paper, a thermal conductive fitting for large work pieces was prepared by using epoxy resin as matrix and α-Al2O3 as filler, and the effect of epoxy resin type,dosage of curing agent and promoting reagent, type and amount of powder filler, post curing condition on the properties of the sealents were investigated.
Abstract: A kind of thermal conductive sealent fitting for large work pieces was prepared by using epoxy resin as matrix and α-Al2O3 as filler.The effect of epoxy resin type,dosage of curing agent and promoting reagent,type and amount of powder filler,post curing condition on the properties of the sealents were investigated.Sealents with high thermal conductivity were obtained by formula optimization,the main key properties of which are better than that of similar foreign products: much lower viscosity of the material before curing,retaining excellent fluidity at 110 ℃ for 1 h,especially convenient for vacuum deaeration and casting operations for large work pieces;thermalconductivity of the cured product reaches to 1.34 W/(m·K);curing shrinkage not more than0.35%;linear expansion coefficient only 27×10-6 K-1 from 25 ℃ to 160 ℃;heat distortion temperature 158 ℃;and has excellent resistance to heat shock and anti-cracking ability.
1 citations