For atmospheric pressure plasma jets(APPJ),the gas temperature is essential for their applications.A spectral diagnosis of APPJ’s gas temperature is conducted in this work.The optical emission spectra of helium APPJ ...For atmospheric pressure plasma jets(APPJ),the gas temperature is essential for their applications.A spectral diagnosis of APPJ’s gas temperature is conducted in this work.The optical emission spectra of helium APPJ are captured by using an optical spectrometer system.Then,the grating secondary spectrum of OH(A2∑+(ν=0)→X2П(ν=0))are used to diagnose the gas temperature of plasmas because the spectrum has excellent resolution.Meanwhile,the vibrational temperatures are estimated by using the vibration sequence of N2band(SPS,the second positive system).On the basis of the method,some important conclusions were obtained.First,the spectral identifying indicates that the grating primary spectrum covers a whole wavelength range from 200 nm to 900 nm,and that the grating secondary spectrum overlaps with the primary spectrum from 400 nm to 900 nm.Second,the gas temperature(about 320 K)is close to the room temperature,while the vibrational temperature of the N2(SPS)is about 5 000 K.The trend of the two temperatures changing with the applied voltage is discussed in the end.展开更多
The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge （SD） plasma is performed. The change of the surface property over time, in comparison with low pressure...The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge （SD） plasma is performed. The change of the surface property over time, in comparison with low pressure oxygen （O2） plasma treatment, is examined. As one compares the treatment by atmospheric pressure plasma to that by the low pressure O2 plasma of PS （polystyrene） the treatment effects were almost in complete agreement. However, when the atmospheric pressure plasma was used for PP（polypropylene）, it produced remarkable hydrophilic effects.展开更多
An atmospheric pressure plasma jet generated in Ar and O2/Ar mixtures has been investigated by specially designed equipment with double power electrodes at 20~32 kHz, and their effects on the cleaning of surfaces have...An atmospheric pressure plasma jet generated in Ar and O2/Ar mixtures has been investigated by specially designed equipment with double power electrodes at 20~32 kHz, and their effects on the cleaning of surfaces have been studied. Properties of the jet discharge are studied by electrical diagnostics, including the waveform of discharge voltage, discharge current and the Q-V Lissajous figures. The optical emission spectroscopy is used to measure the plasma parameters, such as the excitation temperature and the gas temperature. It is found that the consumed power and the excitation temperature increase with increase of the discharge frequency. On the other hand, at the same discharge frequency, these parameters in O2/Ar mixture plasma are found to be much larger. The effect on surface cleaning is studied from the changes in the contact angle. For Ar plasma jet, the contact angle decreases with increase of the discharge frequency. For O2/Ar mixture plasma jet, the contact angle decreases with increase of discharge frequency up to 26 kHz, however, further increase of discharge frequency does not show further decrease in the contact angle. At the same discharge frequency, the contact angle after O2/Ar mixture plasma cleaning is found to be much lower compared to the case of pure Ar. From the results of quadrupole mass-spectrum analysis, we can identify more fragment molecules of CO and H2O in the emitted gases after O2/Ar plasma jet treatment compared with Ar plasma jet treatment, which are produced by the decomposition of surface organic contaminants during the cleaning process.展开更多
A low power atmospheric pressure plasma jet driven by a 24 kHz AC power source and operated with a CH4/air gas mixture has been investigated by optical emission spectrometer. The plasma parameters including the electr...A low power atmospheric pressure plasma jet driven by a 24 kHz AC power source and operated with a CH4/air gas mixture has been investigated by optical emission spectrometer. The plasma parameters including the electron excitation temperature, vibrational temperature and rotational temperature of the plasma jet at different discharge powers are diagnosed based on the assumption that the kinetic energy of the species obeys the Boltzmann distribution. The electron density at different power is also investigated by HS Stark broadening. The results show that the plasma source works under non-equilibrium conditions. It is also found that the vibrational temperature and rotational temperat;ure increase with discharge power, whereas the electron excitation temperature seems to have a downward trend. The electron density increases from 0.8×10^21 m^-3 to 1.1×10^21 m^-3 when the discharge power increases from 53 W to 94 W.展开更多
An atmospheric pressure plasma jet （APPJ） using radio-frequency （13.56 MHz） power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the ex...An atmospheric pressure plasma jet （APPJ） using radio-frequency （13.56 MHz） power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species （atomic helium, atomic oxygen and metastable oxygen） generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2（b1∑g^＋） are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity （777.4 nm） between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.展开更多
Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure(0.1 MPa)without any solvent and co-...Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure(0.1 MPa)without any solvent and co-catalyst leading to 96.1%product yield.It can be reused five times to keep the product yield over 90%.These intriguing results are attributed to a new reaction mechanism,which is supported by theoretical calculations along with the measurements of ^(13)C NMR spectrum and Fourier transform infrared spectroscopy(FT-IR).The excellent catalytic activity can be traced to a CO_(2)-philic group along with an electrophilic hydrogen atom.Our work shows that incorporation of CO_(2)-philic group is an feasible pathway to develop the new efficient ionic liquids.展开更多
对异养小球藻进行常压室温等离子体(Atmospheric and Room Temperature Plasma,ARTP)诱变确定最佳诱变条件,在最佳诱变条件下筛选突变株,并开展突变株的摇瓶培养再验证试验、遗传稳定性试验、50 L发酵罐试验。结果表明,异养小球藻的最...对异养小球藻进行常压室温等离子体(Atmospheric and Room Temperature Plasma,ARTP)诱变确定最佳诱变条件,在最佳诱变条件下筛选突变株,并开展突变株的摇瓶培养再验证试验、遗传稳定性试验、50 L发酵罐试验。结果表明,异养小球藻的最佳致死时间为50 s;得到6株突变株,且其细胞数多于出发菌株、质量浓度明显高于出发菌株;突变性能可以稳定遗传,突变株可提前24 h到达发酵终点,发酵液中油脂产量高于出发菌株。展开更多
Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and qua...Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.展开更多
基金Project supported by China National Fund for Distinguished Young Scientists （51125029）, China Foundation for the Author of National Excellent Doctoral Dissertation （200338）, Intersection Subject Program of Xi＇an Jiaotong University （xjj2012132）, Fundamental Research Fund for the Central Universities （xjj2010160）, China National Science Foundation for Young Scientists （51307133）.
文摘For atmospheric pressure plasma jets(APPJ),the gas temperature is essential for their applications.A spectral diagnosis of APPJ’s gas temperature is conducted in this work.The optical emission spectra of helium APPJ are captured by using an optical spectrometer system.Then,the grating secondary spectrum of OH(A2∑+(ν=0)→X2П(ν=0))are used to diagnose the gas temperature of plasmas because the spectrum has excellent resolution.Meanwhile,the vibrational temperatures are estimated by using the vibration sequence of N2band(SPS,the second positive system).On the basis of the method,some important conclusions were obtained.First,the spectral identifying indicates that the grating primary spectrum covers a whole wavelength range from 200 nm to 900 nm,and that the grating secondary spectrum overlaps with the primary spectrum from 400 nm to 900 nm.Second,the gas temperature(about 320 K)is close to the room temperature,while the vibrational temperature of the N2(SPS)is about 5 000 K.The trend of the two temperatures changing with the applied voltage is discussed in the end.
文摘The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge （SD） plasma is performed. The change of the surface property over time, in comparison with low pressure oxygen （O2） plasma treatment, is examined. As one compares the treatment by atmospheric pressure plasma to that by the low pressure O2 plasma of PS （polystyrene） the treatment effects were almost in complete agreement. However, when the atmospheric pressure plasma was used for PP（polypropylene）, it produced remarkable hydrophilic effects.
基金supported by National Natural Science Foundation of China(Nos.51077008 and 11247239)
文摘An atmospheric pressure plasma jet generated in Ar and O2/Ar mixtures has been investigated by specially designed equipment with double power electrodes at 20~32 kHz, and their effects on the cleaning of surfaces have been studied. Properties of the jet discharge are studied by electrical diagnostics, including the waveform of discharge voltage, discharge current and the Q-V Lissajous figures. The optical emission spectroscopy is used to measure the plasma parameters, such as the excitation temperature and the gas temperature. It is found that the consumed power and the excitation temperature increase with increase of the discharge frequency. On the other hand, at the same discharge frequency, these parameters in O2/Ar mixture plasma are found to be much larger. The effect on surface cleaning is studied from the changes in the contact angle. For Ar plasma jet, the contact angle decreases with increase of the discharge frequency. For O2/Ar mixture plasma jet, the contact angle decreases with increase of discharge frequency up to 26 kHz, however, further increase of discharge frequency does not show further decrease in the contact angle. At the same discharge frequency, the contact angle after O2/Ar mixture plasma cleaning is found to be much lower compared to the case of pure Ar. From the results of quadrupole mass-spectrum analysis, we can identify more fragment molecules of CO and H2O in the emitted gases after O2/Ar plasma jet treatment compared with Ar plasma jet treatment, which are produced by the decomposition of surface organic contaminants during the cleaning process.
文摘A low power atmospheric pressure plasma jet driven by a 24 kHz AC power source and operated with a CH4/air gas mixture has been investigated by optical emission spectrometer. The plasma parameters including the electron excitation temperature, vibrational temperature and rotational temperature of the plasma jet at different discharge powers are diagnosed based on the assumption that the kinetic energy of the species obeys the Boltzmann distribution. The electron density at different power is also investigated by HS Stark broadening. The results show that the plasma source works under non-equilibrium conditions. It is also found that the vibrational temperature and rotational temperat;ure increase with discharge power, whereas the electron excitation temperature seems to have a downward trend. The electron density increases from 0.8×10^21 m^-3 to 1.1×10^21 m^-3 when the discharge power increases from 53 W to 94 W.
基金The project partially supported by National Natural Science Foundation of China (No. 10335040)
文摘An atmospheric pressure plasma jet （APPJ） using radio-frequency （13.56 MHz） power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species （atomic helium, atomic oxygen and metastable oxygen） generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2（b1∑g^＋） are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity （777.4 nm） between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.
基金supported by the National Natural Science Foundation of China(21975064)Program of Henan Center for Outstanding Overseas Scientists(GZS2020011)+1 种基金Henan University's first-class discipline science and technology research project(2018YLTD07,2018YLZDYJ11,2019YLZDYJ09)the Excellent Foreign Experts Project of Henan University。
文摘Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure(0.1 MPa)without any solvent and co-catalyst leading to 96.1%product yield.It can be reused five times to keep the product yield over 90%.These intriguing results are attributed to a new reaction mechanism,which is supported by theoretical calculations along with the measurements of ^(13)C NMR spectrum and Fourier transform infrared spectroscopy(FT-IR).The excellent catalytic activity can be traced to a CO_(2)-philic group along with an electrophilic hydrogen atom.Our work shows that incorporation of CO_(2)-philic group is an feasible pathway to develop the new efficient ionic liquids.
文摘对异养小球藻进行常压室温等离子体(Atmospheric and Room Temperature Plasma,ARTP)诱变确定最佳诱变条件,在最佳诱变条件下筛选突变株,并开展突变株的摇瓶培养再验证试验、遗传稳定性试验、50 L发酵罐试验。结果表明,异养小球藻的最佳致死时间为50 s;得到6株突变株,且其细胞数多于出发菌株、质量浓度明显高于出发菌株;突变性能可以稳定遗传,突变株可提前24 h到达发酵终点,发酵液中油脂产量高于出发菌株。
基金Supported by Heilongjiang Natural Science Foundation Joint Guide Project(LH2019C022)。
文摘Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.
