To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexe...To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexes(average temperature,average moisture content,average retention rate of the total anthocyanin content,temperature contrast value,and moisture dispersion value)were investigated via the response surface method(RSM)and the artificial neural network(ANN)with genetic algorithm(GA).The results showed that the microwave intensity and drying time dominated the changes of evaluation indexes.Overall,the ANN model was superior to the RSM model with better estimation ability,and higher drying uniformity and anthocyanin retention rate were achieved for the ANN-GA model compared with RSM.The optimal parameters were microwave intensity of 5.53 W•g^(-1),air velocity of 1.22 m·s^(-1),and drying time of 5.85 min.This study might provide guidance for process optimization of microwave drying berry fruits.展开更多
An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Us...An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.展开更多
A facile procedure for the synthesis of 3-(2′-amino-3′-cyano-4′-arylpyrid-6′-yl) coumarins are being reported starting from 3- acetylcoumarin, aromatic aldehydes and malononitrile. The reactions were carried out...A facile procedure for the synthesis of 3-(2′-amino-3′-cyano-4′-arylpyrid-6′-yl) coumarins are being reported starting from 3- acetylcoumarin, aromatic aldehydes and malononitrile. The reactions were carried out on microwave irradiation in good yield with short time and easy work-up. The structures of all the compounds have been confirmed on the basis of their analytical, IR, ^1H NMR, and mass spectral data.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
Bis{2-[(2,4-dichloro-phenytimino)-methyl]-4,6-diiodo-phenol}-copper(II) (1) has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n wit...Bis{2-[(2,4-dichloro-phenytimino)-methyl]-4,6-diiodo-phenol}-copper(II) (1) has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 14.7558(17), b = 20.770(2), c = 20.3260(19) A, β = 90.6110(10)°, V= 6229.2(11) A3 and Z = 8. The Cu atom is surrounded by two O atoms and two N atoms from two 2-[(2,4-diehloro-phenylimino)-methyl]-4,6-diiodo-phenol molecules to form a tetrahedral coordination environment. The complex is linked into a column by weak intermolecular interactions.展开更多
通过对法布里-珀罗谐振器的理论分析,说明这种谐振器的基模电磁场分布具有"高斯光束"的形式,在其束腰位置近似为横电磁波,在亚毫米波频段应用于研究超导交流约瑟夫森效应具有优势。应用CST Microwave Studio 2006对其进行仿真...通过对法布里-珀罗谐振器的理论分析,说明这种谐振器的基模电磁场分布具有"高斯光束"的形式,在其束腰位置近似为横电磁波,在亚毫米波频段应用于研究超导交流约瑟夫森效应具有优势。应用CST Microwave Studio 2006对其进行仿真,验证了上述特点并得到谐振模式,谐振器反射镜尺寸,反射镜曲率以及耦合方式对工作状态的影响。适当调整以上参数,可以优化腔内能量的聚集度,从而使谐振器很好地应用于观测约瑟夫森结的夏皮罗台阶。展开更多
We apply a Cross-Correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We...We apply a Cross-Correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We find that the CC method is a powerful tool to examine the WMAP foreground residuals which can be further cleaned accord- ingly. Evident foreground signals are found in the WMAP foreground cleaned maps and the Tegmark cleaned map. In this process 101 point sources are detected, and 26 of them are new sources additional to the originally listed WMAP 208 sources. We estimate the flux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.展开更多
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was des...Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
Some 1-(6-chloroquinoxalin-2-yl)-2-[4-(trifluoromethyl)-2,6-dinitrophenyl] hydrazine derivatives have been synthesized via both conventional and microwave assisted organic synthesis(MAOS) methods. The MAOS metho...Some 1-(6-chloroquinoxalin-2-yl)-2-[4-(trifluoromethyl)-2,6-dinitrophenyl] hydrazine derivatives have been synthesized via both conventional and microwave assisted organic synthesis(MAOS) methods. The MAOS method is more effective on synthesizing these compounds than the conventional method in regard to the higher chemical yields of products(76%-98%) and the shorter reaction time(1-15 min).展开更多
A facile synthesis of trans isomers of 4-aryl-3-methyl-6-oxo-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine-5- carbonitriles via three-component condensation reaction of an aldehyde, 3-amino-5-methylpyrazole and ethyl ...A facile synthesis of trans isomers of 4-aryl-3-methyl-6-oxo-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine-5- carbonitriles via three-component condensation reaction of an aldehyde, 3-amino-5-methylpyrazole and ethyl cyanoacetate in acetonitrile has been developed under microwave irradiation. This one-pot reaction proceeds with-out any catalyst in short times and gives the product in high selectivities and high yields.展开更多
A straightforward and effective procedure for the synthesis of 14-aryl(alkyl)-14H-dibenzo[aj]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the correspondi...A straightforward and effective procedure for the synthesis of 14-aryl(alkyl)-14H-dibenzo[aj]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the corresponding xanthenes in good yields.展开更多
YBa2Cu3O7-δ and Tl2Ba2CaCu2O8 thin films for microwave filters were synthesized by pulsed laser deposition and the two-step thalliation process. Substrate quality requirements and the relation of thin film morphology...YBa2Cu3O7-δ and Tl2Ba2CaCu2O8 thin films for microwave filters were synthesized by pulsed laser deposition and the two-step thalliation process. Substrate quality requirements and the relation of thin film morphology, microstructure with microwave surface resistance were discussed.展开更多
We study the local structure of Cosmic Microwave Background (CMB) temperature maps released by the Wilkinson Microwave Anisotropy Probe (WMAP) team, and find a new kind of structure, which can be described as foll...We study the local structure of Cosmic Microwave Background (CMB) temperature maps released by the Wilkinson Microwave Anisotropy Probe (WMAP) team, and find a new kind of structure, which can be described as follows: a peak (or valley) of average temperature is often followed by a peak of temperature fluctuation that is 4° away. This structure is important for the following reasons: both the well known cold spot detected by Cruz et al. and the hot spot detected by Vielva et al. with the same technology (the third spot in their article) have such structure; more spots that are similar to them can be found on CMB maps and they also tend to be significant cold/hot spots; if we change the 4° characteristic into an artificial one, such as 3° or 5°, there will be less "similar spots", and the temperature peaks or valleys will be less significant. The presented "sim- ilar spots" have passed a strict consistency test which requires them to be significant on at least three different CMB temperature maps. We hope that this article could arouse some interest in the relationship of average temperature with temperature fluctuation in local areas; meanwhile, we are also trying to find an explanation for it which might be important to CMB observation and theory.展开更多
We use observations of Sunyaev-Zel'dovich effect and X-ray surface brightness to reconstruct the radial profiles of gas temperature and density under the assumption of a spherically symmetric distribution of the gas....We use observations of Sunyaev-Zel'dovich effect and X-ray surface brightness to reconstruct the radial profiles of gas temperature and density under the assumption of a spherically symmetric distribution of the gas. The method of reconstruction, first raised by Silk & White, depends directly on the observations of the Sunyaev-Zel'dovich effect and the X-ray surface brightness, without involving additional assumptions such as the equation of state of the gas or the conditions of hydrostatic equilibrium. We applied this method to the cluster RX J1347.5-1145, which has both the Sunyaev-Zel'dovich effect and X-ray observa- tions with relative high precision. It is shown that it will be an effective method to obtain the gas distribution in galaxy clusters. Statistical errors of the derived temperature and density profiles of gas were estimated according to the observational uncertainties.展开更多
The reliable knowledge of seasonal snow volume and its trend is very important to understand Earth’s climate system.Thus,a long-time snow water equivalent(SWE)dataset is necessary.This work presents a daily SWE produ...The reliable knowledge of seasonal snow volume and its trend is very important to understand Earth’s climate system.Thus,a long-time snow water equivalent(SWE)dataset is necessary.This work presents a daily SWE product of 1980-2020 with a linear unmixing method through passive microwave data including SMMR,SSM/I and SSMIS over China after cross-calibration and bias-correction.The unbiased root-mean-square error of snow depth is about 5-7 cm,corresponding to 10-15 mm for SWE,when compared with stations measurements and field snow course data.The spatial patterns and trends of SWE over China present significant regional differences.The overall slope trend presented an insignificant decreasing pattern during 1980-2020 over China;however,there is an obvious fluctuation,i.e.a significant decrease trend during the period 1980-1990,an upward trend from 2005 to 2009,a significant downward trend from 2009 to 2018.The increase of SWE occurred in the Northeast Plain,with an increase trend of 0.2 mm per year.Whereas in the Hengduan Mountains,it presented a downward trend of SWE,up to−0.3 mm per year.In the North Xinjiang,SWE has an increasing trend in the Junggar Basin,while it shows a decreasing trend in the Tianshan and Altai Mountains.展开更多
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexes(average temperature,average moisture content,average retention rate of the total anthocyanin content,temperature contrast value,and moisture dispersion value)were investigated via the response surface method(RSM)and the artificial neural network(ANN)with genetic algorithm(GA).The results showed that the microwave intensity and drying time dominated the changes of evaluation indexes.Overall,the ANN model was superior to the RSM model with better estimation ability,and higher drying uniformity and anthocyanin retention rate were achieved for the ANN-GA model compared with RSM.The optimal parameters were microwave intensity of 5.53 W•g^(-1),air velocity of 1.22 m·s^(-1),and drying time of 5.85 min.This study might provide guidance for process optimization of microwave drying berry fruits.
基金the National Natural Science Foundation of China(No.20372018)
文摘An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.
基金the Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials for financial support(No.JSKC07041).
文摘A facile procedure for the synthesis of 3-(2′-amino-3′-cyano-4′-arylpyrid-6′-yl) coumarins are being reported starting from 3- acetylcoumarin, aromatic aldehydes and malononitrile. The reactions were carried out on microwave irradiation in good yield with short time and easy work-up. The structures of all the compounds have been confirmed on the basis of their analytical, IR, ^1H NMR, and mass spectral data.
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.
基金National Natural Science Foundation of China (Projects 30772627)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘Bis{2-[(2,4-dichloro-phenytimino)-methyl]-4,6-diiodo-phenol}-copper(II) (1) has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 14.7558(17), b = 20.770(2), c = 20.3260(19) A, β = 90.6110(10)°, V= 6229.2(11) A3 and Z = 8. The Cu atom is surrounded by two O atoms and two N atoms from two 2-[(2,4-diehloro-phenylimino)-methyl]-4,6-diiodo-phenol molecules to form a tetrahedral coordination environment. The complex is linked into a column by weak intermolecular interactions.
文摘通过对法布里-珀罗谐振器的理论分析,说明这种谐振器的基模电磁场分布具有"高斯光束"的形式,在其束腰位置近似为横电磁波,在亚毫米波频段应用于研究超导交流约瑟夫森效应具有优势。应用CST Microwave Studio 2006对其进行仿真,验证了上述特点并得到谐振模式,谐振器反射镜尺寸,反射镜曲率以及耦合方式对工作状态的影响。适当调整以上参数,可以优化腔内能量的聚集度,从而使谐振器很好地应用于观测约瑟夫森结的夏皮罗台阶。
基金Supported by the National Natural Science Foundation of China.
文摘We apply a Cross-Correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We find that the CC method is a powerful tool to examine the WMAP foreground residuals which can be further cleaned accord- ingly. Evident foreground signals are found in the WMAP foreground cleaned maps and the Tegmark cleaned map. In this process 101 point sources are detected, and 26 of them are new sources additional to the originally listed WMAP 208 sources. We estimate the flux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.
文摘Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
文摘Some 1-(6-chloroquinoxalin-2-yl)-2-[4-(trifluoromethyl)-2,6-dinitrophenyl] hydrazine derivatives have been synthesized via both conventional and microwave assisted organic synthesis(MAOS) methods. The MAOS method is more effective on synthesizing these compounds than the conventional method in regard to the higher chemical yields of products(76%-98%) and the shorter reaction time(1-15 min).
文摘A facile synthesis of trans isomers of 4-aryl-3-methyl-6-oxo-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine-5- carbonitriles via three-component condensation reaction of an aldehyde, 3-amino-5-methylpyrazole and ethyl cyanoacetate in acetonitrile has been developed under microwave irradiation. This one-pot reaction proceeds with-out any catalyst in short times and gives the product in high selectivities and high yields.
文摘A straightforward and effective procedure for the synthesis of 14-aryl(alkyl)-14H-dibenzo[aj]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the corresponding xanthenes in good yields.
基金The authors are grateful for the measurement of Rs by the University of Electronic Science andTechnology, Chengdu, and the fabrication of filters by the Institute 55, Nanjing. We are also thankful for Prof. Y. F. Chen for her useful discussion and read
文摘YBa2Cu3O7-δ and Tl2Ba2CaCu2O8 thin films for microwave filters were synthesized by pulsed laser deposition and the two-step thalliation process. Substrate quality requirements and the relation of thin film morphology, microstructure with microwave surface resistance were discussed.
基金Supported by the National Natural Science Foundation of China.
文摘We study the local structure of Cosmic Microwave Background (CMB) temperature maps released by the Wilkinson Microwave Anisotropy Probe (WMAP) team, and find a new kind of structure, which can be described as follows: a peak (or valley) of average temperature is often followed by a peak of temperature fluctuation that is 4° away. This structure is important for the following reasons: both the well known cold spot detected by Cruz et al. and the hot spot detected by Vielva et al. with the same technology (the third spot in their article) have such structure; more spots that are similar to them can be found on CMB maps and they also tend to be significant cold/hot spots; if we change the 4° characteristic into an artificial one, such as 3° or 5°, there will be less "similar spots", and the temperature peaks or valleys will be less significant. The presented "sim- ilar spots" have passed a strict consistency test which requires them to be significant on at least three different CMB temperature maps. We hope that this article could arouse some interest in the relationship of average temperature with temperature fluctuation in local areas; meanwhile, we are also trying to find an explanation for it which might be important to CMB observation and theory.
基金supported by the National Science Foundation of China(Grants No.10473002)
文摘We use observations of Sunyaev-Zel'dovich effect and X-ray surface brightness to reconstruct the radial profiles of gas temperature and density under the assumption of a spherically symmetric distribution of the gas. The method of reconstruction, first raised by Silk & White, depends directly on the observations of the Sunyaev-Zel'dovich effect and the X-ray surface brightness, without involving additional assumptions such as the equation of state of the gas or the conditions of hydrostatic equilibrium. We applied this method to the cluster RX J1347.5-1145, which has both the Sunyaev-Zel'dovich effect and X-ray observa- tions with relative high precision. It is shown that it will be an effective method to obtain the gas distribution in galaxy clusters. Statistical errors of the derived temperature and density profiles of gas were estimated according to the observational uncertainties.
基金supported by the Science and Technology Basic Resources Investigation Program of China(2017FY100502)the National Natural Science Foundation of China(42090014,42171317).
文摘The reliable knowledge of seasonal snow volume and its trend is very important to understand Earth’s climate system.Thus,a long-time snow water equivalent(SWE)dataset is necessary.This work presents a daily SWE product of 1980-2020 with a linear unmixing method through passive microwave data including SMMR,SSM/I and SSMIS over China after cross-calibration and bias-correction.The unbiased root-mean-square error of snow depth is about 5-7 cm,corresponding to 10-15 mm for SWE,when compared with stations measurements and field snow course data.The spatial patterns and trends of SWE over China present significant regional differences.The overall slope trend presented an insignificant decreasing pattern during 1980-2020 over China;however,there is an obvious fluctuation,i.e.a significant decrease trend during the period 1980-1990,an upward trend from 2005 to 2009,a significant downward trend from 2009 to 2018.The increase of SWE occurred in the Northeast Plain,with an increase trend of 0.2 mm per year.Whereas in the Hengduan Mountains,it presented a downward trend of SWE,up to−0.3 mm per year.In the North Xinjiang,SWE has an increasing trend in the Junggar Basin,while it shows a decreasing trend in the Tianshan and Altai Mountains.