Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effe...Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.展开更多
Contingent self-esteem captures the fragile nature of self-esteem and is often regarded as suboptimal to psychological functioning.Self-compassion is another important self-related concept assumed to promote mental he...Contingent self-esteem captures the fragile nature of self-esteem and is often regarded as suboptimal to psychological functioning.Self-compassion is another important self-related concept assumed to promote mental health and well-being.However,research on the relation of self-compassion to contingent self-esteem is lacking.Two studies were conducted to explore the role of selfcompassion,either as a personal characteristic or an induced mindset,in influencing the effects of contingent self-esteem on well-being.Study 1 recruited 256 Chinese college students(30.4%male,mean age=21.72 years)who filled out measures of contingent self-esteem,self-compassion,and well-being.The results found that self-compassion moderated the effect of contingent self-esteem on well-being.In Study 2,a sample of 90 Chinese college students(34%male,mean age=18.39 years)were randomly assigned to either a control or self-compassion group.They completed baseline trait measures of contingent self-esteem,self-compassion,and self-esteem.Then,they were led to have a 12-min break(control group)or listen to a 12-min self-compassion audio(self-compassion group),followed by a social stress task and outcome measures.The results demonstrated the effectiveness of the brief self-compassion training and its moderating role in influencing the effects of contingent self-esteem on negative affects after the social stress task.This research provides implications that to equip with a self-compassionate mindset could lower the risk of the impairment of well-being associated with elements of contingent selfesteem,which involves a fragile sense of self-worth.It may also provide insights into the development of an“optimal selfesteem”and the improvement of well-being.展开更多
Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with...Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal(rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride(MA) is evaluated. The rE-DES is produced from the interaction of choline chloride(ChCl) and rare earth metal salts(Cerium, Europium, Lanthanum, and Samarium metal salt)(ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V^(4+)/V^(5+),Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS,were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO_(2)as well as the CO/CO_(2)ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.展开更多
A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and...A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.展开更多
Lanthanum-containing(LaX)and cerium-containing X zeolites(CeX)were prepared by a doubleexchange,double-calcination method.By changing the calcination atmospheres between nitrogen and air,the Ce^(IV) contents in CeX ze...Lanthanum-containing(LaX)and cerium-containing X zeolites(CeX)were prepared by a doubleexchange,double-calcination method.By changing the calcination atmospheres between nitrogen and air,the Ce^(IV) contents in CeX zeolites were adjusted and their impacts on physicochemical properties and catalytic performance in isobutane alkylation were established.The crystallinity of CeX zeolite was found to be negatively correlated with the Ce^(IV) content.This i s believed to be due to the water formed during the oxidation of Ce^(III),which facilitates the framework dealumination.As a consequence,calcining in air resulted in a great elimination of strong Brønsted acid sites while under nitrogen protection,this phenomenon was mostly hindered and the sample’s acidity was preserved.When tested in a continuously flowed slurry reactor,the catalyst lifetime for isobutane alkylation was found to be linearly related to the strong Brønsted acid concentration.In addition,Ce^(3+)was found more benefit for the hydride transfer compared with La^(3+),which is ascribed to the stronger polarization effect on the CH bond of isobutane.Moreover,the decline of hydride transfer activity can be slowed down by the catalytic cracking of the bulky molecules.Based on the product distribution,a new catalytic cycle of dimethylhexanes(DMHs)involving a direct formation of isobutene rather than tert-butyl carbocation was proposed in isobutane alkylation.展开更多
The utilization of lighter alkanes into useful chemical products is essential for modern chemistry and reducing the CO_(2)emission.Particularly,n-butane has gained special attention across the globe due to the abundan...The utilization of lighter alkanes into useful chemical products is essential for modern chemistry and reducing the CO_(2)emission.Particularly,n-butane has gained special attention across the globe due to the abundant production of maleic anhydride(MA).Vanadium phosphorous oxide(VPO)is the most effective catalyst for selective oxidation of n-butane to MA so far.Interestingly,the VPO complex exists in more or less fifteen different structures,each one having distinct phase composition and exclusive surface morphology and physiochemical properties such as valence state,lattice oxygen,acidity etc.,which relies on precursor preparation method and the activation conditions of catalysts.The catalytic performance of VPO catalyst is improved by adding different promoters or co-catalyst such as various metals dopants,or either introducing template or structural-directing agents.Meanwhile,new preparation strategies such as electrospinning,ball milling,hydrothermal,barothermal,ultrasound,microwave irradiation,calcination,sol-gel method and solvothermal synthesis are also employed for introducing improvement in catalytic performance.Research in above-mentioned different aspects will be ascribed in current review in addition to summarizing overall catalysis activity and final yield.To analyze the performance of the catalytic precursor,the reaction mechanism and reaction kinetics both are discussed in this review to help clarify the key issues such as strong exothermic reaction,phosphorus supplement,water supplement,deactivation,and air/n-butane pretreatment etc.related to the various industrial applications of VPO.展开更多
Spray nozzle is a key component in equipment for plant protection and water-saving irrigation. The fan nozzle is a kind of spray nozzle, which is widely used in agriculture and forestry for irrigation and control of d...Spray nozzle is a key component in equipment for plant protection and water-saving irrigation. The fan nozzle is a kind of spray nozzle, which is widely used in agriculture and forestry for irrigation and control of diseases, insects, and weeds. In consideration of the increasing velocity of the flow field, when the hydraulic pressure remains unchanged and the flow path becomes narrow, and because the increase of the velocity of spray drops can increase the penetrability of spray drops into the plant canopy, a kind of new fan nozzle with multi entries and simple inner structure was designed and the influences of its structure parameters on the inner flow field were analyzed using FLUENT software. The experimental results showed that the influence of the throat length on the inner flow field of the nozzle was insignificant, while the orifice grooving degree had a significant effect on inner flow field of the nozzle. The larger the grooving degree was, the smaller the pressure and velocity of internal flow field of the nozzle. The nozzle throat length had little influence on the velocity change of internal flow field. Positive correlation was shown between throat length and flow field velocity.展开更多
[Objectives] To optimize the extraction process of polysaccharides from leaves of Dendrobium officinale. [Methods]The polysaccharides from D. officinale were extracted by internal boiling method. The extraction rate o...[Objectives] To optimize the extraction process of polysaccharides from leaves of Dendrobium officinale. [Methods]The polysaccharides from D. officinale were extracted by internal boiling method. The extraction rate of polysaccharides from D. officinale was studied.Based on the single factor experiment,the L_9( 3~3) orthogonal experiment was designed to optimize the extraction process of polysaccharides from D. officinale. [Results]The optimum process for extracting polysaccharides from D. officinale by internal boiling method was as follows:1. 00 g of D. officinale powder was desorbed with 6. 0 mL of 20% ethanol for 20 min,35. 0 mL of 90℃ water was rapidly added,and the extraction time was 5 min. [Conclusions] Under this condition,the extraction rate of polysaccharides from D. officinale was 12. 31%,which was 3. 75 percentage points higher than that of traditional reflux extraction.展开更多
Maize(Zea mays L.)is a critical staple crop globally,integral to human consumption,food security,and agricultural product stability.The quality and purity of maize seeds,essential for hybrid seed production,are contin...Maize(Zea mays L.)is a critical staple crop globally,integral to human consumption,food security,and agricultural product stability.The quality and purity of maize seeds,essential for hybrid seed production,are contingent upon effective detasseling.This study investigates the evolution of detasseling technologies and their application in Chinese maize hybrid seed production,with a comparative analysis against the United States.A comprehensive examination of the development and utilization of detasseling technology in Chinese maize hybrid seed production was undertaken,with a specific focus on key milestones.Data from the United States were included for comparative purposes.The analysis encompassed various detasseling methods,including manual,semi-mechanized,and cytoplasmic male sterility,as well as more recent innovations such as detasseling machines,and the emerging field of intelligent detasseling driven by unmanned aerial vehicles(UAVs),computer vision,and mechanical arms.Mechanized detasseling methods were predominantly employed by America.Despite the challenges of inflexible and occasionally overlooked,applying detasseling machines is efficient and reliable.At present,China’s detasseling operations in hybrid maize seed production are mainly carried out by manual work,which is labor-intensive and inefficient.In order to address this issue,China is dedicated to developing intelligent detasseling technology.This study emphasizes the critical role of detasseling in hybrid maize seed production.The United States has embraced mechanized detasseling.The application and development of manual and mechanized detasseling were applied later than those in the United States,but latest intelligent detasseling technologies first appeared in China.Intelligent detasseling is expected to be the future direction,ensuring the quality and efficiency of hybrid maize seed production,with implications for global food security.展开更多
Poly(ionic liquids)(PILs)combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in catalysis.In this work,a series of metal-based PIL with different ionic ratios wer...Poly(ionic liquids)(PILs)combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in catalysis.In this work,a series of metal-based PIL with different ionic ratios were prepared for the selective oxidation of cyclohexane.Characterization analysis reveals that different degrees of ionization could adjust the Co-N sites of the catalysts efficiently,leading to significant changes in their electronic structure,which strongly relate to catalytic performance in oxidation.20.07%cyclohexane conversion and 13.06%cyclohexanone and cyclohexanol(KA oil)yield can be achieved by metal-based PILs that are better than other commercial catalysts.Compared with CoCl_(2),metal-based PILs perform well,with superior conversion and KA oil yield.More interestingly,the catalyst created in this study features a malleable Co-N site,which may potentially have an impact on how oxygen species adsorb and desorb from the catalyst.Therefore,the catalyst studied in this work is used as molecular oxygen for the selective oxidation of cyclohexane to produce KA oil,and its application prospect is promising.展开更多
Dry eye disease(DED) is a multifactorial chronic inflammatory disease of the ocular surface with complex and unclear etiology. The development of reliable detection tools for the pathology of DED will benefit its trea...Dry eye disease(DED) is a multifactorial chronic inflammatory disease of the ocular surface with complex and unclear etiology. The development of reliable detection tools for the pathology of DED will benefit its treatment, but it is still lacking. In parallel, it has been discovered recently that viscosity changes are involved in inflammation processes. In this regard, we constructed a fluorescent probe V5with an asymmetric donor-acceptor-donor(D-A-D) feature after rational structural modulation for viscosity detection during DED progression. The probe manifested a remarkable fluorescence enhancement(110 folds) in highly viscous conditions without interferences from polarity and reactive species. Specifically, no aggregation effect of the probe was found in glycerol. Moreover, viscosity increment in human corneal epithelial cells(HCECs) induced by hyperosmosis and inflammation was monitored, and ferroptosis in HCECs also led to the viscosity elevation. A reactive oxygen species(ROS)-dependent viscosity changes during DED progression is demonstrated. Finally, viscosity change in corneal epithelial cell layer from mice treated by scopolamine was also visualized for the first time. We anticipate this work can provide a new lens to the pathogenesis study and diagnosis of DED and other ophthalmic diseases using fluorescence methods.展开更多
Along with the survey on experimental investigations drawing attention to the drag and heat reduction mechanism, the authors simultaneously focus on the recent advances of numerical simulations on the schemes applied ...Along with the survey on experimental investigations drawing attention to the drag and heat reduction mechanism, the authors simultaneously focus on the recent advances of numerical simulations on the schemes applied to supersonic/hypersonic vehicles. The CFD study has evolved as an irreplaceable method in scheme evaluation and aircraft optimization. Similar to our previous experimental survey, the advances in drag and heat reduction schemes are reviewed by similar kinds of mechanism in this article, namely the forward-facing cavity, the opposing jet, the aerospike, the energy deposition and their combinational configurations. This review article puts an emphatic eye on the flow conditions, numerical methods, novel schemes and analytical conclusions given in the simulations. Further, the multi-objective design optimization concept has also been illustrated due to the observable advantages of using CFD over experimental method, especially those performances conducted in drag reduction and thermal protection practice, and this would possess reference value in the design of aircraft system.展开更多
A series of novel 6-(/er/-butyl)-8-fluoro-2,3- dimethylquinoline carbonate derivatives were designed and synthesized. Bioassay results showed that some of them exhibited good activity against Pyricularia oryzae (P. or...A series of novel 6-(/er/-butyl)-8-fluoro-2,3- dimethylquinoline carbonate derivatives were designed and synthesized. Bioassay results showed that some of them exhibited good activity against Pyricularia oryzae (P. oryzae). It was found that the compound 5q (benzyl (6-(tert-butyl)-8-fluoro-2,3-dimethylquinolin-4-yl) carbonate) possessed good activity against P. oryzae whatever protective activity (10 mg·L^-1) or curative activity (25 mg·L^-1), which was better than that of control tebufloquin. In addition, the frontier molecular orbit results revealed that the compound held higher activity against P. oryzae when the total energy was low and the ClogP was high, which may provide useful information for further design novel fungicides.展开更多
Unmanned aerial vehicle(UAV)chemical application is widely used for crop protection,and spraying pattern is one of the most important factors that influence the chemical control efficacy.A method for UAV spraying patt...Unmanned aerial vehicle(UAV)chemical application is widely used for crop protection,and spraying pattern is one of the most important factors that influence the chemical control efficacy.A method for UAV spraying pattern measurement with partial least squares(PLS)model based spectrum analysis was proposed in this study to measure the UAV spraying pattern more accurately.The method involved the steps of fluorescent tracer solution spray and its droplets collection,the spectrum on paper strip acquiring,spectrum processing and analysis,PLS modeling.In order to verify the applicability of the method and obtain the parameters of the PLS model,UAV spraying experiments were performed in the field.Then Fluorescent tracer solution was sprayed and its droplets are collected by paper strip,and the original spectrum on paper strip obtained by a spectrometer was processed by the Savitzky-Golay and standard normalized variable(SNV)method.The prediction model of coverage rate selected as the droplet deposition parameter to measure the UAV spraying pattern,was established by using PLS method.To verify the superiority of the PLS model,a traditional linear regression(LR)model of coverage rate was established simultaneously.The results demonstrate that the method with PLS model based spectrum analysis can measure the UAV spraying pattern effectively,and PLS model has a better performance of RV2=0.94 and RMSEP=0.9446 than that of the LR model.展开更多
基金the National Natural Science Foundation of China(Nos.22209095 and 22238004).
文摘Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.
基金the Jilin Science and Technology Department 20200201280JC,and Shanghai special fund for ideological and political work in Shanghai University of International Business and Economics.
文摘Contingent self-esteem captures the fragile nature of self-esteem and is often regarded as suboptimal to psychological functioning.Self-compassion is another important self-related concept assumed to promote mental health and well-being.However,research on the relation of self-compassion to contingent self-esteem is lacking.Two studies were conducted to explore the role of selfcompassion,either as a personal characteristic or an induced mindset,in influencing the effects of contingent self-esteem on well-being.Study 1 recruited 256 Chinese college students(30.4%male,mean age=21.72 years)who filled out measures of contingent self-esteem,self-compassion,and well-being.The results found that self-compassion moderated the effect of contingent self-esteem on well-being.In Study 2,a sample of 90 Chinese college students(34%male,mean age=18.39 years)were randomly assigned to either a control or self-compassion group.They completed baseline trait measures of contingent self-esteem,self-compassion,and self-esteem.Then,they were led to have a 12-min break(control group)or listen to a 12-min self-compassion audio(self-compassion group),followed by a social stress task and outcome measures.The results demonstrated the effectiveness of the brief self-compassion training and its moderating role in influencing the effects of contingent self-esteem on negative affects after the social stress task.This research provides implications that to equip with a self-compassionate mindset could lower the risk of the impairment of well-being associated with elements of contingent selfesteem,which involves a fragile sense of self-worth.It may also provide insights into the development of an“optimal selfesteem”and the improvement of well-being.
基金supported by the National Key Research and Development Program of China, China (2017YFA0206803)the Innovation Academy for Green Manufacture of Chinese Academy of Science (IAGM2020C17)+1 种基金K. C. Wong Education Foundation (No. GJTD-2018-04)Supported by the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy, China (Grant. YLU-DNL Fund2021016)。
文摘Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal(rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride(MA) is evaluated. The rE-DES is produced from the interaction of choline chloride(ChCl) and rare earth metal salts(Cerium, Europium, Lanthanum, and Samarium metal salt)(ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V^(4+)/V^(5+),Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS,were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO_(2)as well as the CO/CO_(2)ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.
基金supported by the One Hundred Talent Program of CASthe National Natural Science Foundation of China Petroleum & Chemical Corporation Joint Fund(U1662129)+1 种基金the National Natural Science Foundation of China(91434203)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
文摘A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0206803)the National Natural Science Foundation of China(21878315)+3 种基金the Key Programs of the Chinese Academy of Sciences(KFZD-SW-413)the Key Programs of Innovation Academy for Green Manufacture,CAS(IAGM2020C17)K.C.Wong Education Foundation(No.GJTD-2018-04)the Major Program of National Natural Science Foundation of China(21890762).
文摘Lanthanum-containing(LaX)and cerium-containing X zeolites(CeX)were prepared by a doubleexchange,double-calcination method.By changing the calcination atmospheres between nitrogen and air,the Ce^(IV) contents in CeX zeolites were adjusted and their impacts on physicochemical properties and catalytic performance in isobutane alkylation were established.The crystallinity of CeX zeolite was found to be negatively correlated with the Ce^(IV) content.This i s believed to be due to the water formed during the oxidation of Ce^(III),which facilitates the framework dealumination.As a consequence,calcining in air resulted in a great elimination of strong Brønsted acid sites while under nitrogen protection,this phenomenon was mostly hindered and the sample’s acidity was preserved.When tested in a continuously flowed slurry reactor,the catalyst lifetime for isobutane alkylation was found to be linearly related to the strong Brønsted acid concentration.In addition,Ce^(3+)was found more benefit for the hydride transfer compared with La^(3+),which is ascribed to the stronger polarization effect on the CH bond of isobutane.Moreover,the decline of hydride transfer activity can be slowed down by the catalytic cracking of the bulky molecules.Based on the product distribution,a new catalytic cycle of dimethylhexanes(DMHs)involving a direct formation of isobutene rather than tert-butyl carbocation was proposed in isobutane alkylation.
基金supported by the National Key Research and Development Program of China(2017YFA0206803)the innovation Academy for Green Manufacture of Chinese Academy of Science(IAGM2020C17)+3 种基金the Key Programs of the Chinese Academy of Sciences(KFZD-SW-413)the National Nature Science Foundation of China(21808223)the Key Programs of Fujian Institute of Innovation,CAS(FJCXY18020203)Chinese Academy of Sciences,the One Hundred Talent Program of CAS。
文摘The utilization of lighter alkanes into useful chemical products is essential for modern chemistry and reducing the CO_(2)emission.Particularly,n-butane has gained special attention across the globe due to the abundant production of maleic anhydride(MA).Vanadium phosphorous oxide(VPO)is the most effective catalyst for selective oxidation of n-butane to MA so far.Interestingly,the VPO complex exists in more or less fifteen different structures,each one having distinct phase composition and exclusive surface morphology and physiochemical properties such as valence state,lattice oxygen,acidity etc.,which relies on precursor preparation method and the activation conditions of catalysts.The catalytic performance of VPO catalyst is improved by adding different promoters or co-catalyst such as various metals dopants,or either introducing template or structural-directing agents.Meanwhile,new preparation strategies such as electrospinning,ball milling,hydrothermal,barothermal,ultrasound,microwave irradiation,calcination,sol-gel method and solvothermal synthesis are also employed for introducing improvement in catalytic performance.Research in above-mentioned different aspects will be ascribed in current review in addition to summarizing overall catalysis activity and final yield.To analyze the performance of the catalytic precursor,the reaction mechanism and reaction kinetics both are discussed in this review to help clarify the key issues such as strong exothermic reaction,phosphorus supplement,water supplement,deactivation,and air/n-butane pretreatment etc.related to the various industrial applications of VPO.
文摘Spray nozzle is a key component in equipment for plant protection and water-saving irrigation. The fan nozzle is a kind of spray nozzle, which is widely used in agriculture and forestry for irrigation and control of diseases, insects, and weeds. In consideration of the increasing velocity of the flow field, when the hydraulic pressure remains unchanged and the flow path becomes narrow, and because the increase of the velocity of spray drops can increase the penetrability of spray drops into the plant canopy, a kind of new fan nozzle with multi entries and simple inner structure was designed and the influences of its structure parameters on the inner flow field were analyzed using FLUENT software. The experimental results showed that the influence of the throat length on the inner flow field of the nozzle was insignificant, while the orifice grooving degree had a significant effect on inner flow field of the nozzle. The larger the grooving degree was, the smaller the pressure and velocity of internal flow field of the nozzle. The nozzle throat length had little influence on the velocity change of internal flow field. Positive correlation was shown between throat length and flow field velocity.
基金Supported by Key Discipline Independent Project for Chemical Engineering of Guangxi Colleges and Universities(2015KLOG18)Natural Science Foundation Project of Guangxi Zhuang Autonomous Region(2017GXNSFFA198007Key Science and Technology Project of Guangxi(Gui Ke AA17202010)
文摘[Objectives] To optimize the extraction process of polysaccharides from leaves of Dendrobium officinale. [Methods]The polysaccharides from D. officinale were extracted by internal boiling method. The extraction rate of polysaccharides from D. officinale was studied.Based on the single factor experiment,the L_9( 3~3) orthogonal experiment was designed to optimize the extraction process of polysaccharides from D. officinale. [Results]The optimum process for extracting polysaccharides from D. officinale by internal boiling method was as follows:1. 00 g of D. officinale powder was desorbed with 6. 0 mL of 20% ethanol for 20 min,35. 0 mL of 90℃ water was rapidly added,and the extraction time was 5 min. [Conclusions] Under this condition,the extraction rate of polysaccharides from D. officinale was 12. 31%,which was 3. 75 percentage points higher than that of traditional reflux extraction.
基金supported by the“Jie Bang Gua Shuai”Science and Technology Project of Heilongjiang Province(Grant No.20212XJ05A0204)The Outstanding Scientist Cultivation Project of Beijing Academy of Agriculture and Forestry Sciences(Grant No.JKZX202205)Chen Liping Young Beijing Scholars Project.
文摘Maize(Zea mays L.)is a critical staple crop globally,integral to human consumption,food security,and agricultural product stability.The quality and purity of maize seeds,essential for hybrid seed production,are contingent upon effective detasseling.This study investigates the evolution of detasseling technologies and their application in Chinese maize hybrid seed production,with a comparative analysis against the United States.A comprehensive examination of the development and utilization of detasseling technology in Chinese maize hybrid seed production was undertaken,with a specific focus on key milestones.Data from the United States were included for comparative purposes.The analysis encompassed various detasseling methods,including manual,semi-mechanized,and cytoplasmic male sterility,as well as more recent innovations such as detasseling machines,and the emerging field of intelligent detasseling driven by unmanned aerial vehicles(UAVs),computer vision,and mechanical arms.Mechanized detasseling methods were predominantly employed by America.Despite the challenges of inflexible and occasionally overlooked,applying detasseling machines is efficient and reliable.At present,China’s detasseling operations in hybrid maize seed production are mainly carried out by manual work,which is labor-intensive and inefficient.In order to address this issue,China is dedicated to developing intelligent detasseling technology.This study emphasizes the critical role of detasseling in hybrid maize seed production.The United States has embraced mechanized detasseling.The application and development of manual and mechanized detasseling were applied later than those in the United States,but latest intelligent detasseling technologies first appeared in China.Intelligent detasseling is expected to be the future direction,ensuring the quality and efficiency of hybrid maize seed production,with implications for global food security.
基金supported by the National Science Fund for Excellent Young Scholars(22222813)Key Scientific and Technological Projects in Huizhou(2021JBZ5.1)the Joint Fund of Yulin University,and the Dalian National Laboratory for Clean Energy(Grant No.YLU-DNL Fund 2021016)
文摘Poly(ionic liquids)(PILs)combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in catalysis.In this work,a series of metal-based PIL with different ionic ratios were prepared for the selective oxidation of cyclohexane.Characterization analysis reveals that different degrees of ionization could adjust the Co-N sites of the catalysts efficiently,leading to significant changes in their electronic structure,which strongly relate to catalytic performance in oxidation.20.07%cyclohexane conversion and 13.06%cyclohexanone and cyclohexanol(KA oil)yield can be achieved by metal-based PILs that are better than other commercial catalysts.Compared with CoCl_(2),metal-based PILs perform well,with superior conversion and KA oil yield.More interestingly,the catalyst created in this study features a malleable Co-N site,which may potentially have an impact on how oxygen species adsorb and desorb from the catalyst.Therefore,the catalyst studied in this work is used as molecular oxygen for the selective oxidation of cyclohexane to produce KA oil,and its application prospect is promising.
基金supported by the National Natural Science Foundation of China(No.22075281)Zhejiang Provincial Natural Science of Foundation of China(No.LZ21B010001)+1 种基金University of Chinese Academy of Science(No.WIUCASQD2020008)。
文摘Dry eye disease(DED) is a multifactorial chronic inflammatory disease of the ocular surface with complex and unclear etiology. The development of reliable detection tools for the pathology of DED will benefit its treatment, but it is still lacking. In parallel, it has been discovered recently that viscosity changes are involved in inflammation processes. In this regard, we constructed a fluorescent probe V5with an asymmetric donor-acceptor-donor(D-A-D) feature after rational structural modulation for viscosity detection during DED progression. The probe manifested a remarkable fluorescence enhancement(110 folds) in highly viscous conditions without interferences from polarity and reactive species. Specifically, no aggregation effect of the probe was found in glycerol. Moreover, viscosity increment in human corneal epithelial cells(HCECs) induced by hyperosmosis and inflammation was monitored, and ferroptosis in HCECs also led to the viscosity elevation. A reactive oxygen species(ROS)-dependent viscosity changes during DED progression is demonstrated. Finally, viscosity change in corneal epithelial cell layer from mice treated by scopolamine was also visualized for the first time. We anticipate this work can provide a new lens to the pathogenesis study and diagnosis of DED and other ophthalmic diseases using fluorescence methods.
基金support from the National Natural Science Foundation of China (Nos.11502291 & 11802340)
文摘Along with the survey on experimental investigations drawing attention to the drag and heat reduction mechanism, the authors simultaneously focus on the recent advances of numerical simulations on the schemes applied to supersonic/hypersonic vehicles. The CFD study has evolved as an irreplaceable method in scheme evaluation and aircraft optimization. Similar to our previous experimental survey, the advances in drag and heat reduction schemes are reviewed by similar kinds of mechanism in this article, namely the forward-facing cavity, the opposing jet, the aerospike, the energy deposition and their combinational configurations. This review article puts an emphatic eye on the flow conditions, numerical methods, novel schemes and analytical conclusions given in the simulations. Further, the multi-objective design optimization concept has also been illustrated due to the observable advantages of using CFD over experimental method, especially those performances conducted in drag reduction and thermal protection practice, and this would possess reference value in the design of aircraft system.
基金Zhejiang Provincial Natural Science Foundation of China (No.LY16C140007)Research Institute Special Program of Department of Science and Technology of Zhejiang Province (No.2015F50030).
文摘A series of novel 6-(/er/-butyl)-8-fluoro-2,3- dimethylquinoline carbonate derivatives were designed and synthesized. Bioassay results showed that some of them exhibited good activity against Pyricularia oryzae (P. oryzae). It was found that the compound 5q (benzyl (6-(tert-butyl)-8-fluoro-2,3-dimethylquinolin-4-yl) carbonate) possessed good activity against P. oryzae whatever protective activity (10 mg·L^-1) or curative activity (25 mg·L^-1), which was better than that of control tebufloquin. In addition, the frontier molecular orbit results revealed that the compound held higher activity against P. oryzae when the total energy was low and the ClogP was high, which may provide useful information for further design novel fungicides.
基金supported by the One Hundred Talent Program of CASNational Natural Science Foundation of China Petroleum & Chemical Corporation Joint Fund(U1662129)+2 种基金Key Program of National Natural Science Foundation of China(91434203)Key Research Program ofFrontier Sciences,CAS(QYZDY-SSW-JSCO11)State Key Laboratory of Multiphase Complex Systems,IPE,CAS(MPCS-2015-A-05)
基金This study was supported by Zhang Ruirui's Beijing Nova Program(No.Z181100006218029)National Natural Science Foundation of China(31601228)+1 种基金BAAFS'Innovation Ability Construction Program 2018(No.KJCX20180424)National Key R&D Program of China(2016YFD0200701-2).
文摘Unmanned aerial vehicle(UAV)chemical application is widely used for crop protection,and spraying pattern is one of the most important factors that influence the chemical control efficacy.A method for UAV spraying pattern measurement with partial least squares(PLS)model based spectrum analysis was proposed in this study to measure the UAV spraying pattern more accurately.The method involved the steps of fluorescent tracer solution spray and its droplets collection,the spectrum on paper strip acquiring,spectrum processing and analysis,PLS modeling.In order to verify the applicability of the method and obtain the parameters of the PLS model,UAV spraying experiments were performed in the field.Then Fluorescent tracer solution was sprayed and its droplets are collected by paper strip,and the original spectrum on paper strip obtained by a spectrometer was processed by the Savitzky-Golay and standard normalized variable(SNV)method.The prediction model of coverage rate selected as the droplet deposition parameter to measure the UAV spraying pattern,was established by using PLS method.To verify the superiority of the PLS model,a traditional linear regression(LR)model of coverage rate was established simultaneously.The results demonstrate that the method with PLS model based spectrum analysis can measure the UAV spraying pattern effectively,and PLS model has a better performance of RV2=0.94 and RMSEP=0.9446 than that of the LR model.
