Bamboo viscose fibers and conventional viscose fibers were measured by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and thermogravimetric analyzer/FTIR spectr...Bamboo viscose fibers and conventional viscose fibers were measured by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and thermogravimetric analyzer/FTIR spectrometer (TG-FTIR) respectively. At last, the method based on the testing of the Fourier transform near infrared (NIR) spectra was proposed to identify these two kinds of fibers. The discrimination models between bamboo viscose fibers with conventional viscose fibers were built by means of Ward's algorithm and Hierarchical cluster analysis(HCA) after the first derivative and vector normalization pretreatment, and were verified finally. The results indicate that these two kinds of fibers are similar in their morphology both of cross-section and longitudinal direction. What's more, the FTIR spectra, the thermostability, and decomposition products of TG-FTIR experiment are similar, and the testing results contribute little to the effective identification of the two fibers. However, the accuracy of the NIR spectra model is high, and the two kinds of fibers can be classified into two separated groups to achieve the identification simply and exactly.展开更多
An effective method to fabricate two-helix long-period fiber gratings （TH-LFGs） is presented. Based on the coupling mode theory, the conversion of optical vortices （OVs） in TH-LFGs are analyzed in detail. The conv...An effective method to fabricate two-helix long-period fiber gratings （TH-LFGs） is presented. Based on the coupling mode theory, the conversion of optical vortices （OVs） in TH-LFGs are analyzed in detail. The conversions of OVs with different topological charges： 0 → ±2 and 1 → 3 are simulated as three examples and the conversion efficiency higher than 98% can be realized.展开更多
Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retarda...Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retardant viscose fibers at a ratio of 30∶70, and the blended yarns were woven with flame-retardant polyester filaments. Fabrics with different parameters, including fabric weaves, warp yarn densities, and fabric layers, were designed, and the effects of those fabric parameters on mechanical properties and flame-retardant properties were tested and analyzed. The results show that the tearing load of the fabrics is affected by fabric weaves, warp yarn densities, and fabric layers, and the tearing load of the weft mountain weave fabric and the twill weave fabric is higher than that of the plain weave fabric. The bursting load of the fabric increases with the increase of warp yarn densities and layers. Among the tested fabric samples, the triple-layer twill fabric has the best flame-retardant performance, which meets the standard of flame-retardant protective fabric Grade B1 level. The research of this paper would provide guidance for the development and production of polyimide blended fabrics.展开更多
Based on the analysis of the properties of Nomex 450 and Nomex 462,the thermal properties of Nomex 462/Lenzing Viscose Flame retardent(FR)blending materials were analyzed.It was discovered through burning test and The...Based on the analysis of the properties of Nomex 450 and Nomex 462,the thermal properties of Nomex 462/Lenzing Viscose Flame retardent(FR)blending materials were analyzed.It was discovered through burning test and Thermal Gravity(TG)analysis that the blended material was superior in thermal behaviors to the material made from either Nomex or Viscose FR filament,when the ratio of Nomex and Lenzing Viscose FR reached 80∶20,and excellent thermal properties were achieved with the value of Limiting Oxygen Index(LOI)up to 36.1%.Blending Nomex and Viscose FR filaments may be recommended for better fire retardant property of related fabric.展开更多
This paper proposes a mode-locked fber laser based on graphene-coated microfber.The total length of the fber laser resonant cavity is 31.34 m.Under the condition of stable output of bright-dark soliton pairs from the ...This paper proposes a mode-locked fber laser based on graphene-coated microfber.The total length of the fber laser resonant cavity is 31.34 m.Under the condition of stable output of bright-dark soliton pairs from the fber laser,dual-wavelength tuning is realized by adjusting the polarization controller(PC),and the wavelength tuning range is 11 nm.Furthermore,the efects of polarization states on bright-dark solitons are studied.It is demonstrated that the mode-locking state can be switched between conventional solitons and bright-dark solitons in the graphene mode-locked fber laser.Bright-dark soliton pairs with diferent shapes and nanosecond pulse width can be obtained by adjusting the PC and pump power.展开更多
基金General Administration of Quality Supervision,Inspection and Quarantine of the People's Republic of Chinathe Project of Shanghai Municipal Bureau of Quality and Technical Supervision,China(No. 2010-Z17)
文摘Bamboo viscose fibers and conventional viscose fibers were measured by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and thermogravimetric analyzer/FTIR spectrometer (TG-FTIR) respectively. At last, the method based on the testing of the Fourier transform near infrared (NIR) spectra was proposed to identify these two kinds of fibers. The discrimination models between bamboo viscose fibers with conventional viscose fibers were built by means of Ward's algorithm and Hierarchical cluster analysis(HCA) after the first derivative and vector normalization pretreatment, and were verified finally. The results indicate that these two kinds of fibers are similar in their morphology both of cross-section and longitudinal direction. What's more, the FTIR spectra, the thermostability, and decomposition products of TG-FTIR experiment are similar, and the testing results contribute little to the effective identification of the two fibers. However, the accuracy of the NIR spectra model is high, and the two kinds of fibers can be classified into two separated groups to achieve the identification simply and exactly.
基金Supported by the National Natural Science Foundation of China under Grant No 61275049
文摘An effective method to fabricate two-helix long-period fiber gratings （TH-LFGs） is presented. Based on the coupling mode theory, the conversion of optical vortices （OVs） in TH-LFGs are analyzed in detail. The conversions of OVs with different topological charges： 0 → ±2 and 1 → 3 are simulated as three examples and the conversion efficiency higher than 98% can be realized.
基金National Natural Science Foundation of China (No.11802161)Natural Science Foundation of Fujian Province,China (No.2020J05160)Startup Foundation for Doctors of Quanzhou Normal University,China (No.H18012)。
文摘Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retardant viscose fibers at a ratio of 30∶70, and the blended yarns were woven with flame-retardant polyester filaments. Fabrics with different parameters, including fabric weaves, warp yarn densities, and fabric layers, were designed, and the effects of those fabric parameters on mechanical properties and flame-retardant properties were tested and analyzed. The results show that the tearing load of the fabrics is affected by fabric weaves, warp yarn densities, and fabric layers, and the tearing load of the weft mountain weave fabric and the twill weave fabric is higher than that of the plain weave fabric. The bursting load of the fabric increases with the increase of warp yarn densities and layers. Among the tested fabric samples, the triple-layer twill fabric has the best flame-retardant performance, which meets the standard of flame-retardant protective fabric Grade B1 level. The research of this paper would provide guidance for the development and production of polyimide blended fabrics.
文摘Based on the analysis of the properties of Nomex 450 and Nomex 462,the thermal properties of Nomex 462/Lenzing Viscose Flame retardent(FR)blending materials were analyzed.It was discovered through burning test and Thermal Gravity(TG)analysis that the blended material was superior in thermal behaviors to the material made from either Nomex or Viscose FR filament,when the ratio of Nomex and Lenzing Viscose FR reached 80∶20,and excellent thermal properties were achieved with the value of Limiting Oxygen Index(LOI)up to 36.1%.Blending Nomex and Viscose FR filaments may be recommended for better fire retardant property of related fabric.
基金supported by the National Natural Science Foundation of China(Grant Nos.62027825 and 62005024)the Natural Science Foundation of Jilin Province(No.20220101130JC)+1 种基金Jilin Province Young Scientifc and Technological Talents Supporting Project(QT202104)supported by the 111 Project of China(No.D21009).
文摘This paper proposes a mode-locked fber laser based on graphene-coated microfber.The total length of the fber laser resonant cavity is 31.34 m.Under the condition of stable output of bright-dark soliton pairs from the fber laser,dual-wavelength tuning is realized by adjusting the polarization controller(PC),and the wavelength tuning range is 11 nm.Furthermore,the efects of polarization states on bright-dark solitons are studied.It is demonstrated that the mode-locking state can be switched between conventional solitons and bright-dark solitons in the graphene mode-locked fber laser.Bright-dark soliton pairs with diferent shapes and nanosecond pulse width can be obtained by adjusting the PC and pump power.
