A new type of NaCS/PDMDAAC polyelectrolyte complex membrane prepared by interfacial reaction of sodium cellulose sulfate as polyanions and poly(dimethylallylammonium chloride)as polycations was proposed.The static con...A new type of NaCS/PDMDAAC polyelectrolyte complex membrane prepared by interfacial reaction of sodium cellulose sulfate as polyanions and poly(dimethylallylammonium chloride)as polycations was proposed.The static contact angle of the polyelectrolyte complex(PELC)membrane surface was measured to characterize membrane wettability.The effects of concentration of polyelectrolyte,molecular weight,and reaction time on contact angle were investigated.It was found that NaCS/PDMDAAC PELC membrane was hydrophilic.Its contact angle decreased with the increasing concentration of NaCS and molecular weight of PDMDAAC,and increased with the increasing concentration of PDMDAAC and reaction time.展开更多
The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet （TDWP） method with the ＂split operator-Fourier transform＂ scheme. At a given wavelength ...The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet （TDWP） method with the ＂split operator-Fourier transform＂ scheme. At a given wavelength and intensity of laser pulse, the population of each state changing with time is obtained. The photo-absorption spectra and kinetic- energy distribution of the dissociation fragments, which exhibit vibration-level structure and dispersion of the wave packet, respectively, are also obtained. The results show that by increasing the laser intensity, one can find not only the band center shift of the photo-absorption spectrum, but also the change of the fragment energy. The appearance of the diffusive band in the photo-absorption spectrum and the multiple peaks in the kinetic-energy spectrum can be attributed to the effects of the predissoeiation limit and the external field.展开更多
We report a method of high-sensitively detecting the weak signal in photoassociation （PA） spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube....We report a method of high-sensitively detecting the weak signal in photoassociation （PA） spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio （SNR） of the PA spectra is strongly dependent on the integration time and the sensitivity of the lock-in amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na-Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.展开更多
We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by t...We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by the two-step association.The time-dependent Schro¨dinger equation of the association process is solved within a three-state model and the wave packet is propagated with the ＂split operator-Fourier transform＂ scheme and the rotating-wave approximation（RWA）.The vibrational population distribution of the ground state can be obtained by projecting the wave packet to every vibrational level of the ground state.The results not only show that for NaCs achievement of photoassociation production is accompanied by the photodissociation of the higher vibrational molecules,but also show that the vibrational distribution in lower vibrational levels of the ground state changes with the laser parameters.展开更多
向日葵是重要的耐旱、耐盐碱油料作物,其产量与品质对地区经济有重要影响。NAC转录因子是植物中最大的蛋白家族之一,广泛参与植物多种生命活动,并在植物响应非生物与生物胁迫中起重要作用。为揭示向日葵NAC转录因子(HaNAC)密码子的使用...向日葵是重要的耐旱、耐盐碱油料作物,其产量与品质对地区经济有重要影响。NAC转录因子是植物中最大的蛋白家族之一,广泛参与植物多种生命活动,并在植物响应非生物与生物胁迫中起重要作用。为揭示向日葵NAC转录因子(HaNAC)密码子的使用模式和形成原因,利用CUSP、CodonW等软件程序对124个HaNAC基因进行密码子使用模式分析。结果表明,HaNAC基因密码子第1(GC1)、第2(GC2)和第3位碱基(GC3)的GC含量表现为GC1>GC3>GC2,且均低于50%,表明向日葵HaNAC基因密码子偏好使用A/T。有效密码子数(effective number of codons,ENC)表明,HaNAC基因密码子偏好性弱。密码子适应指数(codon adaptation index,CAI)表明,HaNAC基因表达水平低。向日葵NAC基因密码子偏好性受自然选择影响较大,突变压力次之。在HaNAC基因密码子中AGA使用频率最高,共有29个高频密码子和20个最优密码子,且最优密码子偏好A/T结尾。综上,向日葵HaNAC基因密码子使用以A/T碱基为主且偏好A/T结尾,其密码子偏好性主要受自然选择驱动,且偏好性较弱、基因表达水平较低。以上结果为向日葵NAC转录因子的密码子优化、偏好机制及遗传进化研究提供了参考。展开更多
文摘A new type of NaCS/PDMDAAC polyelectrolyte complex membrane prepared by interfacial reaction of sodium cellulose sulfate as polyanions and poly(dimethylallylammonium chloride)as polycations was proposed.The static contact angle of the polyelectrolyte complex(PELC)membrane surface was measured to characterize membrane wettability.The effects of concentration of polyelectrolyte,molecular weight,and reaction time on contact angle were investigated.It was found that NaCS/PDMDAAC PELC membrane was hydrophilic.Its contact angle decreased with the increasing concentration of NaCS and molecular weight of PDMDAAC,and increased with the increasing concentration of PDMDAAC and reaction time.
基金Project supported by the National Natural Science Foundation of China(Grant No.11074151)the Doctoral Program Foundation of Institutions of Higher Education of China(Grant No.20123704110002)
文摘The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet （TDWP） method with the ＂split operator-Fourier transform＂ scheme. At a given wavelength and intensity of laser pulse, the population of each state changing with time is obtained. The photo-absorption spectra and kinetic- energy distribution of the dissociation fragments, which exhibit vibration-level structure and dispersion of the wave packet, respectively, are also obtained. The results show that by increasing the laser intensity, one can find not only the band center shift of the photo-absorption spectrum, but also the change of the fragment energy. The appearance of the diffusive band in the photo-absorption spectrum and the multiple peaks in the kinetic-energy spectrum can be attributed to the effects of the predissoeiation limit and the external field.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the Chang Jiang Scholars and Innovative Research Team in the University of the Ministry of Education of China(Grant No.IRT13076)+2 种基金the National Natural Science Foundation of China(Grant Nos.91436108,61378014,61675121,61705123,and 61722507)the Fund for Shanxi“1331 Project”Key Subjects Construction,Chinathe Foundation for Outstanding Young Scholars of Shanxi Province,China(Grant No.201601D021001)
文摘We report a method of high-sensitively detecting the weak signal in photoassociation （PA） spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio （SNR） of the PA spectra is strongly dependent on the integration time and the sensitivity of the lock-in amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na-Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11074151)the National Basic Research Program of China (Grant No. 2011CB808100)
文摘We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by the two-step association.The time-dependent Schro¨dinger equation of the association process is solved within a three-state model and the wave packet is propagated with the ＂split operator-Fourier transform＂ scheme and the rotating-wave approximation（RWA）.The vibrational population distribution of the ground state can be obtained by projecting the wave packet to every vibrational level of the ground state.The results not only show that for NaCs achievement of photoassociation production is accompanied by the photodissociation of the higher vibrational molecules,but also show that the vibrational distribution in lower vibrational levels of the ground state changes with the laser parameters.
文摘向日葵是重要的耐旱、耐盐碱油料作物,其产量与品质对地区经济有重要影响。NAC转录因子是植物中最大的蛋白家族之一,广泛参与植物多种生命活动,并在植物响应非生物与生物胁迫中起重要作用。为揭示向日葵NAC转录因子(HaNAC)密码子的使用模式和形成原因,利用CUSP、CodonW等软件程序对124个HaNAC基因进行密码子使用模式分析。结果表明,HaNAC基因密码子第1(GC1)、第2(GC2)和第3位碱基(GC3)的GC含量表现为GC1>GC3>GC2,且均低于50%,表明向日葵HaNAC基因密码子偏好使用A/T。有效密码子数(effective number of codons,ENC)表明,HaNAC基因密码子偏好性弱。密码子适应指数(codon adaptation index,CAI)表明,HaNAC基因表达水平低。向日葵NAC基因密码子偏好性受自然选择影响较大,突变压力次之。在HaNAC基因密码子中AGA使用频率最高,共有29个高频密码子和20个最优密码子,且最优密码子偏好A/T结尾。综上,向日葵HaNAC基因密码子使用以A/T碱基为主且偏好A/T结尾,其密码子偏好性主要受自然选择驱动,且偏好性较弱、基因表达水平较低。以上结果为向日葵NAC转录因子的密码子优化、偏好机制及遗传进化研究提供了参考。
