Two measurement techniques are investigated to characterize photodetector linearity. A model for the two-tone and three-tone photodetector systems is developed to thoroughly investigate the influences of setup compone...Two measurement techniques are investigated to characterize photodetector linearity. A model for the two-tone and three-tone photodetector systems is developed to thoroughly investigate the influences of setup components on the measurement results. We demonstrate that small bias shifts from the quadrature point of the modulator will induce deviation into measurement results of the two-tone system, and the simulation results correspond well to experimental and calculation results.展开更多
Based on successive multiple-step isothermal crystallization and self-nucleation annealing methods, a novel semi-quantitative method for the characterization of segment distribution in linear low density polyethylene ...Based on successive multiple-step isothermal crystallization and self-nucleation annealing methods, a novel semi-quantitative method for the characterization of segment distribution in linear low density polyethylene (LLDPE) was established by treating the thermal analysis data using the Gibbs-Thomson equation. The method was used to describe the segment distribution of Ziegler-Natta catalyzed LLDPE (Z-N LLDPE), metallocene catalyzed LLDPE (m-LLDPE) and two commercial LLDPEs with wide molecular weight distribution. The differences of the results obtained from the two thermally treated samples were compared. The results of segment distribution of the polymers were discussed according to their microstructure data and were compared with their characteristics. It can be deduced from the results that this characterization method is effective to characterize the sequence structure of the branched ethylene copolymers.展开更多
Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confir...Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confirms that it crystallizes in orthorhombic crystal system with non-centrosymmetric space group Pna21. The various functional groups were identified qualitatively by Fourier transform-infra red (FT-IR) and FT-Raman techniques. The electron absorption spectrum was studied by UV-Vis spectrophotometer. Thermal behavior of the crystal was evidenced by thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. From DSC the melt ing point of the crystal is found to be 145°C. The existence of second harmonic generation (SHG) signal was evidenced using Kurtz Perry powder test and the efficiency of the crystal was found to be 0.64 times that of the standard KDP crystal.展开更多
以端羟基超支化聚酯(CHBP_x)和顺丁烯二酸酐为原料,合成端羧基线性-超支化聚酯(MHBP_x),并进行中和反应,制备出阴离子型加脂剂.通过测定顺丁烯二酸酐反应率,优化出合成MHBP_x的反应条件为:顺丁烯二酸酐与CHBP_x的摩尔比为1.4∶1,反应温...以端羟基超支化聚酯(CHBP_x)和顺丁烯二酸酐为原料,合成端羧基线性-超支化聚酯(MHBP_x),并进行中和反应,制备出阴离子型加脂剂.通过测定顺丁烯二酸酐反应率,优化出合成MHBP_x的反应条件为:顺丁烯二酸酐与CHBP_x的摩尔比为1.4∶1,反应温度为90℃,反应时间为4h.在该条件下,制备得到了三代产物(MHBP_1、MHBP_2、MHBP_3),并通过FTIR和1 H NMR等手段表征了MHBP_x的分子结构,并具有一定的稳定性,使用激光粒度分析仪测量MHBP_1、MHBP_2、MHBP_3乳液平均粒径为123.8nm、348.9nm和412.1nm.将MHBP_x应用于绵羊皮加脂工艺,并与市售加脂剂SK-70对比,考察了三代产品对成革增厚率、部位差降低率、柔软度、机械强度以及透水汽性的影响,结果表明,该类产品具有提高成革柔软度与撕裂强度的性能.展开更多
以聚酰胺-胺(PAMAM)为核,利用月桂酰氯对其端羟基进行改性,合成了一系列线性-树枝状聚合物(PAMAM-n),其中PAMAM和月桂酰氯的摩尔比分别为1:1(PAMAM-1)、1:3(PAMAM-3)、1:5(PAMAM-5)、1:7(PAMAM-7)。通过FT-IR、1H-NMR、凝胶渗透色谱(GPC...以聚酰胺-胺(PAMAM)为核,利用月桂酰氯对其端羟基进行改性,合成了一系列线性-树枝状聚合物(PAMAM-n),其中PAMAM和月桂酰氯的摩尔比分别为1:1(PAMAM-1)、1:3(PAMAM-3)、1:5(PAMAM-5)、1:7(PAMAM-7)。通过FT-IR、1H-NMR、凝胶渗透色谱(GPC)和羟值测定等手段研究了PAMAM-n的结构,产物的酯化率分别为12.54%、28.78%、43.30%和79.64%。同时研究了PAMAM-n的表面性能和粒径,其表面张力基本上趋于21.38~27.96 m N/m,溶液粒径分布在120.6~457.8 nm之间,其中PAMAM-3具有最为优异的表面活性。随后将性能优异的合成产物PAMAM-3应用于皮革加脂工序中,使用FT-IR、AFM和TG等手段研究了PAMAM-3处理后的蓝湿革的结构、热力学性能。结果表明,通过PAMAM-3处理后的蓝湿革与胶原纤维之间有较强的物理化学作用,并且加脂后的皮革柔软性和增厚性有所提高。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61574019,61674018 and 61674020the Fund of State Key Laboratory of Information Photonics and Optical Communicationsthe Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20130005130001
文摘Two measurement techniques are investigated to characterize photodetector linearity. A model for the two-tone and three-tone photodetector systems is developed to thoroughly investigate the influences of setup components on the measurement results. We demonstrate that small bias shifts from the quadrature point of the modulator will induce deviation into measurement results of the two-tone system, and the simulation results correspond well to experimental and calculation results.
基金Foundation Item：Strategic Environmental Research and Development Program （SERDP）AcknowLedgements Supports from the Strategic Environmental Research and Development Program （SERDP） subcontracted through the University of Iowa as well niversity of Waterloo are also thank two anonymous constructive and insightful as that throug acknowledged. reviewers for suggestions.
基金This work was supported by the Science Foundations of State Key Laboratory of Polymer Physics and Chemisny, Chinese Academy of Sciences (00-B-15) and National Natural Science Foundation of China (No. B040504).
文摘Based on successive multiple-step isothermal crystallization and self-nucleation annealing methods, a novel semi-quantitative method for the characterization of segment distribution in linear low density polyethylene (LLDPE) was established by treating the thermal analysis data using the Gibbs-Thomson equation. The method was used to describe the segment distribution of Ziegler-Natta catalyzed LLDPE (Z-N LLDPE), metallocene catalyzed LLDPE (m-LLDPE) and two commercial LLDPEs with wide molecular weight distribution. The differences of the results obtained from the two thermally treated samples were compared. The results of segment distribution of the polymers were discussed according to their microstructure data and were compared with their characteristics. It can be deduced from the results that this characterization method is effective to characterize the sequence structure of the branched ethylene copolymers.
文摘Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confirms that it crystallizes in orthorhombic crystal system with non-centrosymmetric space group Pna21. The various functional groups were identified qualitatively by Fourier transform-infra red (FT-IR) and FT-Raman techniques. The electron absorption spectrum was studied by UV-Vis spectrophotometer. Thermal behavior of the crystal was evidenced by thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. From DSC the melt ing point of the crystal is found to be 145°C. The existence of second harmonic generation (SHG) signal was evidenced using Kurtz Perry powder test and the efficiency of the crystal was found to be 0.64 times that of the standard KDP crystal.
文摘以端羟基超支化聚酯(CHBP_x)和顺丁烯二酸酐为原料,合成端羧基线性-超支化聚酯(MHBP_x),并进行中和反应,制备出阴离子型加脂剂.通过测定顺丁烯二酸酐反应率,优化出合成MHBP_x的反应条件为:顺丁烯二酸酐与CHBP_x的摩尔比为1.4∶1,反应温度为90℃,反应时间为4h.在该条件下,制备得到了三代产物(MHBP_1、MHBP_2、MHBP_3),并通过FTIR和1 H NMR等手段表征了MHBP_x的分子结构,并具有一定的稳定性,使用激光粒度分析仪测量MHBP_1、MHBP_2、MHBP_3乳液平均粒径为123.8nm、348.9nm和412.1nm.将MHBP_x应用于绵羊皮加脂工艺,并与市售加脂剂SK-70对比,考察了三代产品对成革增厚率、部位差降低率、柔软度、机械强度以及透水汽性的影响,结果表明,该类产品具有提高成革柔软度与撕裂强度的性能.
文摘以聚酰胺-胺(PAMAM)为核,利用月桂酰氯对其端羟基进行改性,合成了一系列线性-树枝状聚合物(PAMAM-n),其中PAMAM和月桂酰氯的摩尔比分别为1:1(PAMAM-1)、1:3(PAMAM-3)、1:5(PAMAM-5)、1:7(PAMAM-7)。通过FT-IR、1H-NMR、凝胶渗透色谱(GPC)和羟值测定等手段研究了PAMAM-n的结构,产物的酯化率分别为12.54%、28.78%、43.30%和79.64%。同时研究了PAMAM-n的表面性能和粒径,其表面张力基本上趋于21.38~27.96 m N/m,溶液粒径分布在120.6~457.8 nm之间,其中PAMAM-3具有最为优异的表面活性。随后将性能优异的合成产物PAMAM-3应用于皮革加脂工序中,使用FT-IR、AFM和TG等手段研究了PAMAM-3处理后的蓝湿革的结构、热力学性能。结果表明,通过PAMAM-3处理后的蓝湿革与胶原纤维之间有较强的物理化学作用,并且加脂后的皮革柔软性和增厚性有所提高。
