A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phas...A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phase transition behavior and crystallinity were characterized by IR,elemental analysis, TG-DTA, polarizing optical microscope (POM) equipped with a hot stage and X-ray diffraction techniques. The results demonstrate that all the synthesized polyesters exhibit nematic liquid crystalline phases and show relatively high glass transition temperatures and good thermal stability.展开更多
Experiments were conducted on a trickle bed with 0.283m ID to elucidate the relationship between hysteretic phenomena and liquid distribution. The hysteresis of pressure drop and the variance of radial liquid distribu...Experiments were conducted on a trickle bed with 0.283m ID to elucidate the relationship between hysteretic phenomena and liquid distribution. The hysteresis of pressure drop and the variance of radial liquid distribution were observed simultaneously. Residence time distribution (RTD), holdup and mean residence time (RT) of liquid phase were also found to demonstrate hysteresis of the same nature. RTD, liquid holdup and mean RT calculated with a simple model from the distribution of liquid flow rate show characteristics consistant with the experimental data, suggesting that the hyteretic phenomena originate from the multiplicity and nonuniformity of liquid flow distribution.展开更多
The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently...The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently, the trajectory of a droplet in the channel can be tracked, and the trajectories of all drops are observed in order to statistically analyse the drops for capture or entrainment. Therefore, in terms of theoretical model of motion, the stratified two phase flow systems are studied in the mixture of nitrobenzene and concentrated sulfuric acid. The analytical results indicate that the trajectories of droplets of different diameters are different at the same location. The larger droplets can help to promote the efficiency of plate separators. The thickness of trickling film has a significant influence on the efficiency of numerical simulation when the concentration of the dispersed phase is greater than 10%. So the modification of thickness of trickling film can help to get the real flow field efficiency. The low flow rate lowers the average Renolds number so that the lighter phase droplets have sufficient time to interact with the trickling film. It is an indispensable factor for predicting efficiency that coalesced drops flow off inclined plates together with trickling films. A comparison confirms that the simulation results are in good agreement with the experiment results.展开更多
[Objective] The aim was to conduct HPLC analysis on Cordyceps Sinensis/Betaine compound feed nutriment. [Method] Cordyceps Sinensis/Betaine compound feed nutriment was under HPLC analysis to determine separation of Co...[Objective] The aim was to conduct HPLC analysis on Cordyceps Sinensis/Betaine compound feed nutriment. [Method] Cordyceps Sinensis/Betaine compound feed nutriment was under HPLC analysis to determine separation of Cordyceps Sinensis effluent and betaine. [Result] Different compositions in Cordyceps Sinensis/etaine compound feed nutriment would be well separated by the method. [Conclusion] The method provides a suitable platform of separation and analysis for Cordyceps Sinensis /Betaine compound feed nutriment.展开更多
Ultrafiltration （UF） experiments were subjected to the concentration of Shi- itake polyphenol（SP） with ultrasound （US） enhancement, by which the effects of the main parameters such as ultrasonic power, transmemb...Ultrafiltration （UF） experiments were subjected to the concentration of Shi- itake polyphenol（SP） with ultrasound （US） enhancement, by which the effects of the main parameters such as ultrasonic power, transmembrane pressure, temperature and axial flow-rate on the membrane fluxes were analyzed, and then the SP of the ultrafiltrate after follow-up resin adsorption by HPLC was investigated. The results in- dicated that US could significantly enhance the membrane fluxes. The optimal con- ditions obtained was as follows： 0.60 W/cm2 US power, axial flow-rate of 80 L/h, operation temperature 30 ~C, transmembrane pressure 0.10 MPa. US increased the absorption capacity of the absorbent resin during the following stage. The HPLC analysis also showed that catechins were purified to some extent as the ultrafiltrate was treated by US and macroporous resin, indicating the technology of US en- hancement coupled with UF showed the potential for concentration and purification of SP by absorbent resins.展开更多
Saffron, obtained from the flower stigmas of Crocus sativus L., is one of the most expensive food spices. The introduction of saffron in alpine areas could help to broaden and diversify the activities of mountain mult...Saffron, obtained from the flower stigmas of Crocus sativus L., is one of the most expensive food spices. The introduction of saffron in alpine areas could help to broaden and diversify the activities of mountain multifunctional farms, with a positive impact on economy and land management. According to ISO 3632(2010/2011), saffron can be classified into three categories of quality(I, II, III) depending on the concentration of the three main metabolites responsible for its characteristic colour, flavor and aroma: Crocin, Picrocrocin and Safranal. This study represents the first investigation of the quality of saffron produced in the Italian Alps evaluated with spectrophotometry, HPLC, solid-phase microextraction(SPME), and gas chromatographic analysis combined with mass spectrometry(GC/MS). The experiments used Crocus sativus stigmas produced in 2012-2013 in different areas of the Central Italian Alps were located at an altitude between 720 and 1200 m a.s.l.. Results obtained were compared to commercial saffron. The analyses confirmed that all samples can be classified in the first quality category according to the ISO classification. This high quality is also confirmed by HPLC analysis. Moreover, the SPME-GC/MS analysis identified some differences in the aromatic profile of saffron samples, in particular regarding safranal concentration. A preliminary assessment of the economic viability of high quality saffron production for local markets was also performed. Our study provides valid information regarding the quality and economic sustainability of saffron production in the alpine area confirming this crop as a good candidate for a new source of income for multifunctional farms in mountain areas.展开更多
Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispers...Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.展开更多
文摘A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phase transition behavior and crystallinity were characterized by IR,elemental analysis, TG-DTA, polarizing optical microscope (POM) equipped with a hot stage and X-ray diffraction techniques. The results demonstrate that all the synthesized polyesters exhibit nematic liquid crystalline phases and show relatively high glass transition temperatures and good thermal stability.
基金Supported by the National Natural Science Foundation of China(No.29676042).
文摘Experiments were conducted on a trickle bed with 0.283m ID to elucidate the relationship between hysteretic phenomena and liquid distribution. The hysteresis of pressure drop and the variance of radial liquid distribution were observed simultaneously. Residence time distribution (RTD), holdup and mean residence time (RT) of liquid phase were also found to demonstrate hysteresis of the same nature. RTD, liquid holdup and mean RT calculated with a simple model from the distribution of liquid flow rate show characteristics consistant with the experimental data, suggesting that the hyteretic phenomena originate from the multiplicity and nonuniformity of liquid flow distribution.
文摘The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently, the trajectory of a droplet in the channel can be tracked, and the trajectories of all drops are observed in order to statistically analyse the drops for capture or entrainment. Therefore, in terms of theoretical model of motion, the stratified two phase flow systems are studied in the mixture of nitrobenzene and concentrated sulfuric acid. The analytical results indicate that the trajectories of droplets of different diameters are different at the same location. The larger droplets can help to promote the efficiency of plate separators. The thickness of trickling film has a significant influence on the efficiency of numerical simulation when the concentration of the dispersed phase is greater than 10%. So the modification of thickness of trickling film can help to get the real flow field efficiency. The low flow rate lowers the average Renolds number so that the lighter phase droplets have sufficient time to interact with the trickling film. It is an indispensable factor for predicting efficiency that coalesced drops flow off inclined plates together with trickling films. A comparison confirms that the simulation results are in good agreement with the experiment results.
文摘[Objective] The aim was to conduct HPLC analysis on Cordyceps Sinensis/Betaine compound feed nutriment. [Method] Cordyceps Sinensis/Betaine compound feed nutriment was under HPLC analysis to determine separation of Cordyceps Sinensis effluent and betaine. [Result] Different compositions in Cordyceps Sinensis/etaine compound feed nutriment would be well separated by the method. [Conclusion] The method provides a suitable platform of separation and analysis for Cordyceps Sinensis /Betaine compound feed nutriment.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201303080)Hubei Agricultural Science&Technology Innovation Center Project(2014-620-007-001)Natural Science Foundation of Hubei Province of China(2013CFB053)
文摘Ultrafiltration （UF） experiments were subjected to the concentration of Shi- itake polyphenol（SP） with ultrasound （US） enhancement, by which the effects of the main parameters such as ultrasonic power, transmembrane pressure, temperature and axial flow-rate on the membrane fluxes were analyzed, and then the SP of the ultrafiltrate after follow-up resin adsorption by HPLC was investigated. The results in- dicated that US could significantly enhance the membrane fluxes. The optimal con- ditions obtained was as follows： 0.60 W/cm2 US power, axial flow-rate of 80 L/h, operation temperature 30 ~C, transmembrane pressure 0.10 MPa. US increased the absorption capacity of the absorbent resin during the following stage. The HPLC analysis also showed that catechins were purified to some extent as the ultrafiltrate was treated by US and macroporous resin, indicating the technology of US en- hancement coupled with UF showed the potential for concentration and purification of SP by absorbent resins.
基金partly supported by "Accordo di Programma, affermazione in Edolo del Centro di Eccellenza Università della Montagna" MIURUniversità degli Studi di Milano, prot. no. 386 1293-05/08/2011 and by Fondazione della Comunità Bresciana- Onlus
文摘Saffron, obtained from the flower stigmas of Crocus sativus L., is one of the most expensive food spices. The introduction of saffron in alpine areas could help to broaden and diversify the activities of mountain multifunctional farms, with a positive impact on economy and land management. According to ISO 3632(2010/2011), saffron can be classified into three categories of quality(I, II, III) depending on the concentration of the three main metabolites responsible for its characteristic colour, flavor and aroma: Crocin, Picrocrocin and Safranal. This study represents the first investigation of the quality of saffron produced in the Italian Alps evaluated with spectrophotometry, HPLC, solid-phase microextraction(SPME), and gas chromatographic analysis combined with mass spectrometry(GC/MS). The experiments used Crocus sativus stigmas produced in 2012-2013 in different areas of the Central Italian Alps were located at an altitude between 720 and 1200 m a.s.l.. Results obtained were compared to commercial saffron. The analyses confirmed that all samples can be classified in the first quality category according to the ISO classification. This high quality is also confirmed by HPLC analysis. Moreover, the SPME-GC/MS analysis identified some differences in the aromatic profile of saffron samples, in particular regarding safranal concentration. A preliminary assessment of the economic viability of high quality saffron production for local markets was also performed. Our study provides valid information regarding the quality and economic sustainability of saffron production in the alpine area confirming this crop as a good candidate for a new source of income for multifunctional farms in mountain areas.
基金supported by the Hundred Talents Program of Chinese Academy of Sciences(Y20245YBR1)the National Natural Science Foundation of China(21402215 and 61474124)the financial support from Shandong Province Higher Education Science and Technology Program(J16LA01)
文摘Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.
