Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback ...Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system.展开更多
Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to...Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.展开更多
In 1945, I began my campus life as a physics major in Zhongyang (National) University.I graduated from the University in July 1949 and obtained my MS degree when it was renamed Nanjing University in the same year.The ...In 1945, I began my campus life as a physics major in Zhongyang (National) University.I graduated from the University in July 1949 and obtained my MS degree when it was renamed Nanjing University in the same year.The next year,I worked as a teaching assistant at Nanjing College of Pharmacy.From 1950 to 1981.I taught physics at Nanjing University in the status of a teaching assistant first,then a lecturer and展开更多
Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol （OP） in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in su...Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol （OP） in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in surface water in Jinan, China was analyzed by gas chromatography-mass spectrometry （GC-MS） coupled with solid phase extraction （SPE）. Water samples were extracted by SPE on a cartridge system containing C-18 as sorbent. To increase sensitivity and selectivity, OP was derivatized to 4-tert-octyl-phenoxy silane. With the use of phenanthrene-d10 as internal standard, the detection limit based on signal-to-noise ratio （S/N = 3） was 0.06 ng/mL. The average recovery was from 84.67% to 109.7%. The precision of the method given as the relative standard deviations （RSD） was within the range 6.24%-12.96%. In the target water samples, the concentrations of OP were as follows： 15.88-71.24 ng/L for Jinxiuchuan Reservoir, 3.850-26.68 ng/L for the city moat, 6.930-41.56 ng/L for Daming Lake, 66.03-474.2 ng/L for Xiaoqing River, 14.66-17.72 ng/L for the Yellow River, and 10.60-26.43 ng/L for Queshan Reservoir. The Xiaoqing River was seriously polluted due to the discharge of wastewater from Jinan. Jinxiuchuan Reservoir had a higher concentration of OP compared with the Yellow River and Queshan Reservoir, which is ascribed to the surrounding human activities. These data are reported for the first time, providing strong support for the control of OP pollution in Jinan.展开更多
Variations in elastic wave velocity low-frequency internal friction and acoustic emission in granite were experimentally studied as a function of temperature. It isfound that the wave velocity and Young’s modulus ten...Variations in elastic wave velocity low-frequency internal friction and acoustic emission in granite were experimentally studied as a function of temperature. It isfound that the wave velocity and Young’s modulus tend to decrease with temperature.In association with the α- β transition of quartz a sharq internal friction peak can berecognized accompanied by a drastic drop in wave velocity and modulus and by a secondpeak of acoustic emission rate.展开更多
1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some rese...1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some researchershave done much work on internal friction.But most of them were concerned withphase transformation internal frictionof martensite and reverse martensite andfew of them were about internal friction展开更多
In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let ...In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.展开更多
The phase boundary,of α_2 precipitation at 600℃ in Ti-AI-La ternary system has been de- termined by TEM examination,which shows three kinds of phase regions,namely the single α phase region,the transitional phase r...The phase boundary,of α_2 precipitation at 600℃ in Ti-AI-La ternary system has been de- termined by TEM examination,which shows three kinds of phase regions,namely the single α phase region,the transitional phase region where there is superlattice reflection but no α_2 precipitation,and the α+α_2 region.A point of maximum aluminium content was found to exist on the α/(α+α_2)boundary and the track of the boundary was explained in terms of the internal oxidation of lanthanum and the electron concentration rule for α_2 formation.展开更多
为简化前处理过程,降低方法的检出限,进行了题示研究。采集鱼塘底泥样品,混匀、缩分、冷冻干燥、除杂、研磨、过筛后混匀,分取5.00 g,加入10.0μg·L^(-1)^(13)C_(6)-氯硝柳胺水合物标准溶液0.2 m L和含2.0%(体积分数)氨水的乙腈溶...为简化前处理过程,降低方法的检出限,进行了题示研究。采集鱼塘底泥样品,混匀、缩分、冷冻干燥、除杂、研磨、过筛后混匀,分取5.00 g,加入10.0μg·L^(-1)^(13)C_(6)-氯硝柳胺水合物标准溶液0.2 m L和含2.0%(体积分数)氨水的乙腈溶液20 m L,涡旋1 min,超声10 min,离心8 min。上清液于45℃旋蒸至近干,加入2.00 m L 70%(体积分数)乙腈溶液涡旋溶解残留物,再加入200 mg C18涡旋振荡30 s,离心5 min。收集上清液,过0.22μm有机滤膜,滤液采用高效液相色谱-串联质谱法测定。在色谱分析中,以Waters Atiantis^(TM) d C_(18)色谱柱为固定相,水-乙腈体系为流动相进行梯度洗脱;在质谱分析中,以电喷雾离子源负离子(ESI-)模式电离,选择反应监测(SRM)模式检测,内标法定量。结果显示,氯硝柳胺的质量浓度在0.20~50.00μg·L^(-1)内和其定量离子峰面积与同位素内标定量离子峰面积的比值呈线性关系,检出限(3S/N)为0.2μg·kg^(-1)。按照标准加入法进行回收试验,回收率为92.1%~113%,测定值的相对标准偏差(n=6)为1.6%~5.9%。方法用于实际样品的分析,检出的氯硝柳胺的质量分数为0.580~2.18 mg·kg^(-1)。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62275272)the Training Program for Excellent Young Innovators of Changsha(Grant No.KQ2305025)。
文摘Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system.
基金Project supported by the National Natural Science Foundation of China(No.21878026)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX19_1798)+1 种基金the Jiangsu Province University Blue Projectthe Project of Higher Education Reform in Jiangsu Province(No.2019JSJG022),China。
文摘Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.
文摘In 1945, I began my campus life as a physics major in Zhongyang (National) University.I graduated from the University in July 1949 and obtained my MS degree when it was renamed Nanjing University in the same year.The next year,I worked as a teaching assistant at Nanjing College of Pharmacy.From 1950 to 1981.I taught physics at Nanjing University in the status of a teaching assistant first,then a lecturer and
基金supported by the State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (No. KF2009-13)the National Natural Science Foundation of China (No. 21007019, 21107030,21277059, 21277060)
文摘Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol （OP） in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in surface water in Jinan, China was analyzed by gas chromatography-mass spectrometry （GC-MS） coupled with solid phase extraction （SPE）. Water samples were extracted by SPE on a cartridge system containing C-18 as sorbent. To increase sensitivity and selectivity, OP was derivatized to 4-tert-octyl-phenoxy silane. With the use of phenanthrene-d10 as internal standard, the detection limit based on signal-to-noise ratio （S/N = 3） was 0.06 ng/mL. The average recovery was from 84.67% to 109.7%. The precision of the method given as the relative standard deviations （RSD） was within the range 6.24%-12.96%. In the target water samples, the concentrations of OP were as follows： 15.88-71.24 ng/L for Jinxiuchuan Reservoir, 3.850-26.68 ng/L for the city moat, 6.930-41.56 ng/L for Daming Lake, 66.03-474.2 ng/L for Xiaoqing River, 14.66-17.72 ng/L for the Yellow River, and 10.60-26.43 ng/L for Queshan Reservoir. The Xiaoqing River was seriously polluted due to the discharge of wastewater from Jinan. Jinxiuchuan Reservoir had a higher concentration of OP compared with the Yellow River and Queshan Reservoir, which is ascribed to the surrounding human activities. These data are reported for the first time, providing strong support for the control of OP pollution in Jinan.
文摘Variations in elastic wave velocity low-frequency internal friction and acoustic emission in granite were experimentally studied as a function of temperature. It isfound that the wave velocity and Young’s modulus tend to decrease with temperature.In association with the α- β transition of quartz a sharq internal friction peak can berecognized accompanied by a drastic drop in wave velocity and modulus and by a secondpeak of acoustic emission rate.
文摘1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some researchershave done much work on internal friction.But most of them were concerned withphase transformation internal frictionof martensite and reverse martensite andfew of them were about internal friction
基金supported by National Natural Science Foundation of China(61403013)the Aero-Science Foundation of China(2015ZA51009)
文摘In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.
文摘The phase boundary,of α_2 precipitation at 600℃ in Ti-AI-La ternary system has been de- termined by TEM examination,which shows three kinds of phase regions,namely the single α phase region,the transitional phase region where there is superlattice reflection but no α_2 precipitation,and the α+α_2 region.A point of maximum aluminium content was found to exist on the α/(α+α_2)boundary and the track of the boundary was explained in terms of the internal oxidation of lanthanum and the electron concentration rule for α_2 formation.
文摘为简化前处理过程,降低方法的检出限,进行了题示研究。采集鱼塘底泥样品,混匀、缩分、冷冻干燥、除杂、研磨、过筛后混匀,分取5.00 g,加入10.0μg·L^(-1)^(13)C_(6)-氯硝柳胺水合物标准溶液0.2 m L和含2.0%(体积分数)氨水的乙腈溶液20 m L,涡旋1 min,超声10 min,离心8 min。上清液于45℃旋蒸至近干,加入2.00 m L 70%(体积分数)乙腈溶液涡旋溶解残留物,再加入200 mg C18涡旋振荡30 s,离心5 min。收集上清液,过0.22μm有机滤膜,滤液采用高效液相色谱-串联质谱法测定。在色谱分析中,以Waters Atiantis^(TM) d C_(18)色谱柱为固定相,水-乙腈体系为流动相进行梯度洗脱;在质谱分析中,以电喷雾离子源负离子(ESI-)模式电离,选择反应监测(SRM)模式检测,内标法定量。结果显示,氯硝柳胺的质量浓度在0.20~50.00μg·L^(-1)内和其定量离子峰面积与同位素内标定量离子峰面积的比值呈线性关系,检出限(3S/N)为0.2μg·kg^(-1)。按照标准加入法进行回收试验,回收率为92.1%~113%,测定值的相对标准偏差(n=6)为1.6%~5.9%。方法用于实际样品的分析,检出的氯硝柳胺的质量分数为0.580~2.18 mg·kg^(-1)。
