used－silical capillary columns containing heptakis（2、3、6－tri－o－pentyl）-β-cyclodextrinand dibenzo-18-crown-6 were prepared．By studying the selectivity of mixed stationary phases forsome solute pairs.as well a...used－silical capillary columns containing heptakis（2、3、6－tri－o－pentyl）-β-cyclodextrinand dibenzo-18-crown-6 were prepared．By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis（2．3、6-tri-O-pentyl）-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature．mixed ratio and linear velocity of carrier gas．展开更多
A new simulation model for the development of gas condensate reservoirs is introduced based on the influence that phase change,non-Darcy flow,and capillary pressure have on the production of gas condensates.The model ...A new simulation model for the development of gas condensate reservoirs is introduced based on the influence that phase change,non-Darcy flow,and capillary pressure have on the production of gas condensates.The model predicts well performance,including bottom-hole pressure,oil/gas production rate,oil/gas recovery,gaseoil ratio,and the change in produced fluid composition.It also calculates dynamic characters,such as the change of pressure field and oil/gas saturation field during the development of gas condensate reservoirs.The model is applicable to different boundary conditions(both constant-pressure and sealed boundary)and different production modes(both constant-pressure and constant-volume production modes).Model validation attempted using numerical simulation results for sealed boundary conditions with constant-pressure production mode has shown a relatively good match,proving its validity.For constant-pressure boundary conditions with constant-volume production mode,four stages are defined according to the dynamic behavior of production performance in the development of gas condensate reservoirs.展开更多
Heptakis(2.6-di-O-pentyl-3-O-ally)-β-cyclodextrin as an excellent gas chromatographic stationary phase separating phenol and cresol isomers is described.
Mg-Al layered double hydroxide intercalated with CO_(3)^(2-)(CO_(3)·Mg-Al LDH) is effective for treating HCl exhaust gas.HCl reacts with CO_(3)^(2-) in CO_(3)·Mg-Al LDH, resulting in the formation of Cl·...Mg-Al layered double hydroxide intercalated with CO_(3)^(2-)(CO_(3)·Mg-Al LDH) is effective for treating HCl exhaust gas.HCl reacts with CO_(3)^(2-) in CO_(3)·Mg-Al LDH, resulting in the formation of Cl·Mg-Al LDH.We propose that CO_(2) can be used for the desorption of Cl^(-)from Cl·Mg-Al LDH to regenerate CO_(3)·Mg-Al LDH.Herein,we studied the desorption of a from CI-Mg-Al LDH by adding water to Cl·Mg-Al LDH and blowing CO_(2) into it.We also analyzed the effects of temperature and water addition speed on the desorption of CI^(-)from Cl·Mg-Al LDH.Our results show that the added water adhered to CI·Mg-Al LDH and that CO_(2) in the gaseous phase was dissolved in this adhered water,thus generating CO_(3)^(2-).Therefore,anion exchange occurred between CO_(3)^(2-) and Cl^(-)in the Cl·Mg-Al LDH,thus desorbing Cl^(-).展开更多
As concepts closely related to microwave absorption properties,impedance matching and phase matching were rarely combined with material parameters to regulate properties and explore related mechanisms.In this work,red...As concepts closely related to microwave absorption properties,impedance matching and phase matching were rarely combined with material parameters to regulate properties and explore related mechanisms.In this work,reduction–diffusion method was innovatively applied to synthesize rare earth alloy Y_(2)Fe_(17).In order to regulate the electromagnetic parameters of absorbers,the Y_(2)Fe_(17)N_(3-δ)particles were coated with silica(Y_(2)Fe_(17)N_(3-δ)@SiO_(2))and absorbers with different volume fractions were prepared.The relationship between impedance matching,matching thickness,and the strongest reflection loss peak(RLmin)was presented obviously.Compared to the microwave absorption properties of Y_(2)Fe_(17)N_(3-δ)/PU absorber,Y_(2)Fe_(17)N_(3-δ)@SiO_(2)/PU absorbers are more conducive to the realization of microwave absorption material standards which are thin thickness,light weight,strong absorbing intensity,and broad bandwidth.Based on microwave frequency bands,the microwave absorption properties of the absorbers were analyzed and the related parameters were listed.As an important parameter related to perfect matching,reflection factor(√ε_(r)/μ_(r))was discussed combined with microwave amplitude attenuation.According to the origin and mathematical model of bandwidth,the formula of EAB(RL<-10 dB)was derived and simplified.The calculated bandwidths agreed well with experimental results.展开更多
建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证...建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证，同位素内标法定量。在1～40μg / L 范围内氟乐灵农药的线性关系良好；方法定量限（LOQ）为0.02μg / kg；对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验，平均回收率均处于80％～100％之间，RSD≤10.3％；无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。展开更多
We carried out new photometric observations of asteroid （106） Dione at three apparitions （2004, 2012 and 2015） to understand its basic physical properties. Based on a new brightness model, new photometric observat...We carried out new photometric observations of asteroid （106） Dione at three apparitions （2004, 2012 and 2015） to understand its basic physical properties. Based on a new brightness model, new photometric observational data and published data of （106） Dione were analyzed to characterize the morphology of Dione＇s photometric phase curve. In this brightness model, a cellinoid ellipsoid shape and three-parameter （H, G1, G2） magnitude phase function system were involved. Such a model can not only solve the phase function system parameters of （106） Dione by considering an asymmetric shape of an asteroid, but also can be applied to more asteroids, especially those without enough photometric data to solve the convex shape. Using a Markov Chain Monte Carlo （MCMC） method, Dione＇s absolute magnitude of H = 7.66＋0.03-0.03 mag, and phase function parameters G1 = 0.682＋0.077-0.077 and G2 = 0.081＋0.042-0.042 were obtained. Simultaneously, Dione＇s simplistic shape, orientation of pole and rotation period were also determined preliminarily.展开更多
As more attention is being paid to the characteristics of atmospheric amines,there is also an increasing demand for reliable detection technologies.Herein,a method was developed for simultaneous detection of atmospher...As more attention is being paid to the characteristics of atmospheric amines,there is also an increasing demand for reliable detection technologies.Herein,a method was developed for simultaneous detection of atmospheric amines in both gaseous and particulate phases using gas chromatography-mass spectrometry(GC-MS).The amine samples were collected with and without phosphoric acid filters,followed by derivatization with benzenesulfonyl chloride under alkaline condition prior to GC-MS analysis.Furthermore,the method was optimized and validated for determining 14 standard amines.The detection limits ranged from0.0408-0.421μg/mL(for gaseous samples)and 0.163-1.69μg/mL(for particulate samples),respectively.The obtained recoveries ranged from 68.8%-180%and the relative standard deviation was less than 30%,indicating high precision and good reliability of the method.Seven amines were simultaneously detected in gaseous and particulate samples in an industrial park using the developed method successfully.Methylamine,dimethylamine and diethylamine together accounted for 76.7%and 75.6%of particulate and gaseous samples,respectively.By comparing the measured and predicted values of gas-particle partition fractions,it was found that absorption process of aqueous phase played a more important role in the gas-partition of amines than physical adsorption.Moreover,the reaction between unprotonated amines and acid(aq.)in water phase likely promoted water absorption.Higher measured partition fraction of dibutylamine was likely due to the reaction with gaseous HCl.The developed method would help provide a deeper understanding of gas-particle partitioning as well as atmospheric evolution of amines.展开更多
Extremely small-sized iron oxide nanoparticles(ESIONPs)with sizes less than 5 nm have shown great promise as T_(1)contrast agents for magnetic resonance imaging(MRI).However,their facile and scalable production with s...Extremely small-sized iron oxide nanoparticles(ESIONPs)with sizes less than 5 nm have shown great promise as T_(1)contrast agents for magnetic resonance imaging(MRI).However,their facile and scalable production with simultaneously endowed biocompatible surface chemistry remains difficult to be realized.In this study,by using the coprecipitation method implemented in a specially designed gas/liquid mixed phase fluidic reactor,polyglucose sorbitol carboxymethyether(PSC)coated ESIONPs were continuously synthesized with controllable particle sizes ranging from 1.8 to 4 nm.Among the differently sized ESIONPs,the 3.7-nm ESIONPs exhibit the best performance as T_(1)MRI contrast agent,featuring a high r_(1) value of 4.11(mmol L^(−1))^(−1)s^(−1)and low r_(2)/r_(1) ratio of 7.90 under a clinical 3 T MR scanning,as well as the excellent T_(1)MRI contrast effect in not only water but also the cellular environment and blood vessel.Furthermore,the ESIONPs possess long-term stability and good dispersity in aqueous dispersions,making them ideal candidates as safe and effective T_(1)-weighted MRI contrast agent for real clinical use.展开更多
In this paper a modifed continuous energy law was explored to investigate transport behavior in a gas metal arc welding(GMAW)system.The energy law equality at a discrete level for the GMAW system was derived by using ...In this paper a modifed continuous energy law was explored to investigate transport behavior in a gas metal arc welding(GMAW)system.The energy law equality at a discrete level for the GMAW system was derived by using the finite element scheme.The mass conservation and current density continuous equation with the penalty scheme was applied 10 improve the stability.According to the phase-field model coupled with the energy law preserving method,the GMAW model was discretized and a metal transfer process with a pulse current was simulated.It was found that the numerical solution agrees well with the data of the metal transfer process obtained by high-speed photography.Compared with the numerical solution of the volume of fuid model,which was widely studied in the GMAW system based on the finite element method Euler scheme,the energy law preserving method can provide better accuracy in predicting the shape evolution of the droplet and with a greater computing efficiency.展开更多
文摘used－silical capillary columns containing heptakis（2、3、6－tri－o－pentyl）-β-cyclodextrinand dibenzo-18-crown-6 were prepared．By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis（2．3、6-tri-O-pentyl）-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature．mixed ratio and linear velocity of carrier gas．
基金supported by a National Science and Technology Major Project(2016ZX05048003).
文摘A new simulation model for the development of gas condensate reservoirs is introduced based on the influence that phase change,non-Darcy flow,and capillary pressure have on the production of gas condensates.The model predicts well performance,including bottom-hole pressure,oil/gas production rate,oil/gas recovery,gaseoil ratio,and the change in produced fluid composition.It also calculates dynamic characters,such as the change of pressure field and oil/gas saturation field during the development of gas condensate reservoirs.The model is applicable to different boundary conditions(both constant-pressure and sealed boundary)and different production modes(both constant-pressure and constant-volume production modes).Model validation attempted using numerical simulation results for sealed boundary conditions with constant-pressure production mode has shown a relatively good match,proving its validity.For constant-pressure boundary conditions with constant-volume production mode,four stages are defined according to the dynamic behavior of production performance in the development of gas condensate reservoirs.
文摘Heptakis(2.6-di-O-pentyl-3-O-ally)-β-cyclodextrin as an excellent gas chromatographic stationary phase separating phenol and cresol isomers is described.
文摘Mg-Al layered double hydroxide intercalated with CO_(3)^(2-)(CO_(3)·Mg-Al LDH) is effective for treating HCl exhaust gas.HCl reacts with CO_(3)^(2-) in CO_(3)·Mg-Al LDH, resulting in the formation of Cl·Mg-Al LDH.We propose that CO_(2) can be used for the desorption of Cl^(-)from Cl·Mg-Al LDH to regenerate CO_(3)·Mg-Al LDH.Herein,we studied the desorption of a from CI-Mg-Al LDH by adding water to Cl·Mg-Al LDH and blowing CO_(2) into it.We also analyzed the effects of temperature and water addition speed on the desorption of CI^(-)from Cl·Mg-Al LDH.Our results show that the added water adhered to CI·Mg-Al LDH and that CO_(2) in the gaseous phase was dissolved in this adhered water,thus generating CO_(3)^(2-).Therefore,anion exchange occurred between CO_(3)^(2-) and Cl^(-)in the Cl·Mg-Al LDH,thus desorbing Cl^(-).
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFB3501300)the National Natural Science Foundation of China(Grant No.51731001)the Fund from the State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization’s Key Research and Development Projects。
文摘As concepts closely related to microwave absorption properties,impedance matching and phase matching were rarely combined with material parameters to regulate properties and explore related mechanisms.In this work,reduction–diffusion method was innovatively applied to synthesize rare earth alloy Y_(2)Fe_(17).In order to regulate the electromagnetic parameters of absorbers,the Y_(2)Fe_(17)N_(3-δ)particles were coated with silica(Y_(2)Fe_(17)N_(3-δ)@SiO_(2))and absorbers with different volume fractions were prepared.The relationship between impedance matching,matching thickness,and the strongest reflection loss peak(RLmin)was presented obviously.Compared to the microwave absorption properties of Y_(2)Fe_(17)N_(3-δ)/PU absorber,Y_(2)Fe_(17)N_(3-δ)@SiO_(2)/PU absorbers are more conducive to the realization of microwave absorption material standards which are thin thickness,light weight,strong absorbing intensity,and broad bandwidth.Based on microwave frequency bands,the microwave absorption properties of the absorbers were analyzed and the related parameters were listed.As an important parameter related to perfect matching,reflection factor(√ε_(r)/μ_(r))was discussed combined with microwave amplitude attenuation.According to the origin and mathematical model of bandwidth,the formula of EAB(RL<-10 dB)was derived and simplified.The calculated bandwidths agreed well with experimental results.
文摘建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证，同位素内标法定量。在1～40μg / L 范围内氟乐灵农药的线性关系良好；方法定量限（LOQ）为0.02μg / kg；对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验，平均回收率均处于80％～100％之间，RSD≤10.3％；无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。
基金funded by the National Natural Science Foundation of China(Grant Nos.11073051,11473066 and 11673063)the Open Project of Key Laboratory of Space Object and Debris Observation,Chinese Academy of Sciences(title:Photometric study of space debris in near geostationary orbit)
文摘We carried out new photometric observations of asteroid （106） Dione at three apparitions （2004, 2012 and 2015） to understand its basic physical properties. Based on a new brightness model, new photometric observational data and published data of （106） Dione were analyzed to characterize the morphology of Dione＇s photometric phase curve. In this brightness model, a cellinoid ellipsoid shape and three-parameter （H, G1, G2） magnitude phase function system were involved. Such a model can not only solve the phase function system parameters of （106） Dione by considering an asymmetric shape of an asteroid, but also can be applied to more asteroids, especially those without enough photometric data to solve the convex shape. Using a Markov Chain Monte Carlo （MCMC） method, Dione＇s absolute magnitude of H = 7.66＋0.03-0.03 mag, and phase function parameters G1 = 0.682＋0.077-0.077 and G2 = 0.081＋0.042-0.042 were obtained. Simultaneously, Dione＇s simplistic shape, orientation of pole and rotation period were also determined preliminarily.
基金supported from the National Natural Science Foundation of China(Nos.42020104001 and 41805103)Local Innovative and Research Team Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the Fund from Chemistry and Chemical Engineering Guangdong Laboratory(No.1922009)
文摘As more attention is being paid to the characteristics of atmospheric amines,there is also an increasing demand for reliable detection technologies.Herein,a method was developed for simultaneous detection of atmospheric amines in both gaseous and particulate phases using gas chromatography-mass spectrometry(GC-MS).The amine samples were collected with and without phosphoric acid filters,followed by derivatization with benzenesulfonyl chloride under alkaline condition prior to GC-MS analysis.Furthermore,the method was optimized and validated for determining 14 standard amines.The detection limits ranged from0.0408-0.421μg/mL(for gaseous samples)and 0.163-1.69μg/mL(for particulate samples),respectively.The obtained recoveries ranged from 68.8%-180%and the relative standard deviation was less than 30%,indicating high precision and good reliability of the method.Seven amines were simultaneously detected in gaseous and particulate samples in an industrial park using the developed method successfully.Methylamine,dimethylamine and diethylamine together accounted for 76.7%and 75.6%of particulate and gaseous samples,respectively.By comparing the measured and predicted values of gas-particle partition fractions,it was found that absorption process of aqueous phase played a more important role in the gas-partition of amines than physical adsorption.Moreover,the reaction between unprotonated amines and acid(aq.)in water phase likely promoted water absorption.Higher measured partition fraction of dibutylamine was likely due to the reaction with gaseous HCl.The developed method would help provide a deeper understanding of gas-particle partitioning as well as atmospheric evolution of amines.
基金supported by the grant received from the National Key Research and Development Program of China(2017YFA0104302)the Key Project of the National Natural Science Foundation of China(NSFC,51832001)+1 种基金the National Natural Science Innovative Research Group Project(61821002)the Project of the National Natural Science Foundation of China(31800843)。
文摘Extremely small-sized iron oxide nanoparticles(ESIONPs)with sizes less than 5 nm have shown great promise as T_(1)contrast agents for magnetic resonance imaging(MRI).However,their facile and scalable production with simultaneously endowed biocompatible surface chemistry remains difficult to be realized.In this study,by using the coprecipitation method implemented in a specially designed gas/liquid mixed phase fluidic reactor,polyglucose sorbitol carboxymethyether(PSC)coated ESIONPs were continuously synthesized with controllable particle sizes ranging from 1.8 to 4 nm.Among the differently sized ESIONPs,the 3.7-nm ESIONPs exhibit the best performance as T_(1)MRI contrast agent,featuring a high r_(1) value of 4.11(mmol L^(−1))^(−1)s^(−1)and low r_(2)/r_(1) ratio of 7.90 under a clinical 3 T MR scanning,as well as the excellent T_(1)MRI contrast effect in not only water but also the cellular environment and blood vessel.Furthermore,the ESIONPs possess long-term stability and good dispersity in aqueous dispersions,making them ideal candidates as safe and effective T_(1)-weighted MRI contrast agent for real clinical use.
基金Yanhai Lin was supported by the National Natural Science Foundation of China(Grant No.11702101)the Fundamental Research Funds for the Central Universities and the Promo-tion Program for Young and Middle aged Teacher in Science and Technology Research of Huaqiao University(Grant No.ZQN-PY502)+1 种基金the Natural Science Foundation of Fujian Province(Grant No.2019105093)Quanzhou High-Level Talents Support Plan.
文摘In this paper a modifed continuous energy law was explored to investigate transport behavior in a gas metal arc welding(GMAW)system.The energy law equality at a discrete level for the GMAW system was derived by using the finite element scheme.The mass conservation and current density continuous equation with the penalty scheme was applied 10 improve the stability.According to the phase-field model coupled with the energy law preserving method,the GMAW model was discretized and a metal transfer process with a pulse current was simulated.It was found that the numerical solution agrees well with the data of the metal transfer process obtained by high-speed photography.Compared with the numerical solution of the volume of fuid model,which was widely studied in the GMAW system based on the finite element method Euler scheme,the energy law preserving method can provide better accuracy in predicting the shape evolution of the droplet and with a greater computing efficiency.
