Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product s...Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product synth-esis.This review comprehensively examines the key steps and catalytic systems involved in the conversion of cel-lulose to isosorbide.Initially,the reaction pathway from cellulose to isosorbide is elucidated,emphasizing three critical steps:cellulose hydrolysis,glucose hydrogenation,and the two-step dehydration of sorbitol to produce isosorbide.Additionally,the activation energy and acidic sites during cellulose hydrolysis,the impact of metal particle size and catalyst support on hydrogenation,and the effects of catalyst acidity,pore structure,and reaction conditions on sorbitol dehydration have been thoroughly examined.Finally,the progress made in cellulose con-version to isosorbide is summarized,current challenges are highlighted,and future development trends are pro-jected in this review.展开更多
WE observe that the response speed of a linear timeinvariant system to a step reference input depends not only on the system parameters but also on the magnitude of the step input.Based on this observation,we demonstr...WE observe that the response speed of a linear timeinvariant system to a step reference input depends not only on the system parameters but also on the magnitude of the step input.Based on this observation,we demonstrate a method to schedule the magnitude of the reference input to achieve a faster response.展开更多
Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 str...Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 stroke survivors from two neurology wards into an intervention group(n=55)who received the stepped self-care program and a control group(n=55)who received usual care from June to December 2023.The Self-Care of Stroke Inventory,Stroke Self-Efficacy Questionnaire,and the short version of the Stroke Specific Quality of Life Scale were administered at baseline(T0),immediately post-intervention(T_(1)),and at 1-month(T_(2))and 3-month(T_(3))follow-ups.Data were analyzed using repeated measures analyses of variance,and generalized estimating equations.Results A total of 48 participants in the intervention group and 50 participants in the control group completed the study.No statistically significant differences were observed at T0 in any of the measured indicators(all P>0.05).The study showed significant group,time,and group×time interaction effects across the assessed outcomes(all P<0.05).Follow-up between-group comparisons at T_(1),T_(2),and T_(3) indicated that the intervention group had significantly higher scores in self-care maintenance,self-care monitoring,self-care management,self-efficacy,and quality of life than the control group(all P<0.001).Conclusions The stepped self-care program significantly improved self-care behaviors,self-efficacy,and quality of life among stroke survivors.These findings support the broader implementation of this approach in post-discharge home self-care.展开更多
Step ladder-structured nitrocellulose(LNC)is a novel energetic binder prepared by chemically modifying nitrocellulose(NC)with the introduction of flexible polyethylene glycol(PEG-400)chain segments,with a regular stru...Step ladder-structured nitrocellulose(LNC)is a novel energetic binder prepared by chemically modifying nitrocellulose(NC)with the introduction of flexible polyethylene glycol(PEG-400)chain segments,with a regular structure and good performance of bonding.The step ladder-structured addresses critical limitations of NC-based propellants,including low-temperature brittleness and high sensitivity,while enhancing process safety.Although the structural,thermal,and other properties of LNC have been investigated in our previous research,there is a lack of systematic studies on the rheological properties during solution and gelatinization.The study of the relationship between the structural features and rheological properties of LNC is a key factor in guiding its gelatinization and improving the properties of LNC-based propellants.Steady-state rheology flow experiments revealed that LNC exhibited shear thinning in different solutions,which decreased with increasing concentration.It has desirable solu-bility and dispersion in N,N-dimethylformamide(DMF)solvent.The effect of solvents on the entan-glement or orientation of LNC molecular chains may be reduced.These results can be quantitatively demonstrated using the Herschel-Bulkley model.Dynamic viscoelastic studies identified a critical point of concentration-frequency of 2.5 rad/s.This particular frequency point is a turning point in the law of the effect of concentration on the loss factor(tanδ).For gelatinized systems,increasing the solvent content reduces the temperature sensitivity of the gelatinized materials.The viscosity-temperature correlation based on the Arrhenius equation allowed the optimization of the solvent content through the derived equilibrium relationship.These structure-rheological performance relationships establish basic guidelines for the precision gelatinization of LNC-based propellant,provide theoretical support for the replacement of conventional NC by LNC,and guide the gelatinization process to improve the performance of gun propellants.展开更多
Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the fail...Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the failure mechanism of conversion-alloy anodes is ascribed to volume expansion or the shuttle effect,which,however,fails to adequately explain their characteristic electrochemical behavior:an initial rapid drop and then a gradual decline in capacity.Herein,by combining electrochemical characterizations with multi-scale microscopies,spectroscopy,and theoretical calculations,we systematically analyze the failure mechanism of Bi_(2)Te_(3),a typical conversion-alloy anode.The failure processes and mechanisms are identified into two stages:(1)the rapid capacity fading dominated by the shuttle effect in the first several cycles and(2)the gradual material deactivation and capacity decline due to solid-electrolyte interphase accumulation in the following cycles.Furthermore,in response to these failure mechanisms,an elaborate design of Bi_(2)Te_(3)-based electrode featuring ultrafine nanoparticles and carbon encapsulation is presented,which exhibits prominent capability in avoiding the above negative effects and substantially enhancing cycling stability.This study reveals the failure mechanism of conversion-alloy anode throughout its entire life cycle,and the gained insight may lead to targeted optimization strategies for stable high-capacity electrodes.展开更多
This study investigates the motion behavior of a slender flexible particle in a backward-facing step(BFS)flow using the direct-forcing fictitious domain method,with a particular focus on the trapping phenomena near th...This study investigates the motion behavior of a slender flexible particle in a backward-facing step(BFS)flow using the direct-forcing fictitious domain method,with a particular focus on the trapping phenomena near the separation vortex region.Three distinct motion modes are identified:periodic rotation or oscillation within the vortex(trapping),downstream transport(escape),and transition state exhibiting unstable trapping.A dynamic balance among inward migration,centrifugal effects,wall interactions,and elastic forces enables the particle to achieve stable orbital motion within two distinct limit cycles.The topology of these orbits is governed by parameters,including the aspect ratio,structural flexibility,deformation intensity,and fluid inertia,all of which are characterized by the Reynolds number(Re).Specifically,fluid inertia plays a dominant role in facilitating particle trapping.At a fixed Re,a particle with a smaller aspect ratio tends to migrate inward and become trapped,whereas one with a larger aspect ratio is more likely to escape.Structural flexibility,especially when enhanced by confinement near the wall,leads to elastic deformation that induces secondary vortices and a weak flipping motion.The deformation intensityαsignificantly influences the lateral migration of the slender particle after the initial release;a largerαcauses it to drift toward the channel centerline,increasing the probability of escape.These findings provide a theoretical foundation for optimizing the transport and capture of slender soft swimmers in complex flow environments.展开更多
In this paper,a fast step heterodyne light-induced thermoelastic spectroscopy(SH-LITES)sensor using a high-frequency quartz tuning fork(QTF)with resonant frequency of~100 kHz is reported for the first time.The theoret...In this paper,a fast step heterodyne light-induced thermoelastic spectroscopy(SH-LITES)sensor using a high-frequency quartz tuning fork(QTF)with resonant frequency of~100 kHz is reported for the first time.The theoretical principle of heterodyne LITES(H-LITES)signal generation is analyzed firstly,and an acetylene(C_(2)H_(2))H-LITES sensor is established to verify its performance.Experimental comparisons between the high-frequency QTF and a standard commercial QTF with resonant frequency of~32.768 kHz reveal that the high-frequency QTF exhibits a tenfold faster response time.Specifically,the H-LITES sensor with this QTF achieves a 33 ms measurement cycle,90%shorter than commercial counterparts.Furthermore,The SH-LITES technique is proposed to further shorten the scanning time to 15 ms,which achieves the shortest LITES measurement time known to date.To demonstrate its advantages in dynamic gas detection,an H_(2)O-LITES system integrating both QTF types is constructed for real-time monitoring of H_(2)O concentration during different respiration patterns.Comparative measurements show that the SH-LITES more accurately captures dynamic H_(2)O concentration fluctuations during respiration,outperforming the commercial QTF-based H-LITES sensor in rapid response scenarios.展开更多
The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is ...The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.展开更多
文摘Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product synth-esis.This review comprehensively examines the key steps and catalytic systems involved in the conversion of cel-lulose to isosorbide.Initially,the reaction pathway from cellulose to isosorbide is elucidated,emphasizing three critical steps:cellulose hydrolysis,glucose hydrogenation,and the two-step dehydration of sorbitol to produce isosorbide.Additionally,the activation energy and acidic sites during cellulose hydrolysis,the impact of metal particle size and catalyst support on hydrogenation,and the effects of catalyst acidity,pore structure,and reaction conditions on sorbitol dehydration have been thoroughly examined.Finally,the progress made in cellulose con-version to isosorbide is summarized,current challenges are highlighted,and future development trends are pro-jected in this review.
文摘WE observe that the response speed of a linear timeinvariant system to a step reference input depends not only on the system parameters but also on the magnitude of the step input.Based on this observation,we demonstrate a method to schedule the magnitude of the reference input to achieve a faster response.
基金The National Natural Science Foundation of China[72174184]provided policy and financialsupport for this research.
文摘Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 stroke survivors from two neurology wards into an intervention group(n=55)who received the stepped self-care program and a control group(n=55)who received usual care from June to December 2023.The Self-Care of Stroke Inventory,Stroke Self-Efficacy Questionnaire,and the short version of the Stroke Specific Quality of Life Scale were administered at baseline(T0),immediately post-intervention(T_(1)),and at 1-month(T_(2))and 3-month(T_(3))follow-ups.Data were analyzed using repeated measures analyses of variance,and generalized estimating equations.Results A total of 48 participants in the intervention group and 50 participants in the control group completed the study.No statistically significant differences were observed at T0 in any of the measured indicators(all P>0.05).The study showed significant group,time,and group×time interaction effects across the assessed outcomes(all P<0.05).Follow-up between-group comparisons at T_(1),T_(2),and T_(3) indicated that the intervention group had significantly higher scores in self-care maintenance,self-care monitoring,self-care management,self-efficacy,and quality of life than the control group(all P<0.001).Conclusions The stepped self-care program significantly improved self-care behaviors,self-efficacy,and quality of life among stroke survivors.These findings support the broader implementation of this approach in post-discharge home self-care.
基金supported by the National Natural Science Foundation of China(No.22475100 and 22075146).
文摘Step ladder-structured nitrocellulose(LNC)is a novel energetic binder prepared by chemically modifying nitrocellulose(NC)with the introduction of flexible polyethylene glycol(PEG-400)chain segments,with a regular structure and good performance of bonding.The step ladder-structured addresses critical limitations of NC-based propellants,including low-temperature brittleness and high sensitivity,while enhancing process safety.Although the structural,thermal,and other properties of LNC have been investigated in our previous research,there is a lack of systematic studies on the rheological properties during solution and gelatinization.The study of the relationship between the structural features and rheological properties of LNC is a key factor in guiding its gelatinization and improving the properties of LNC-based propellants.Steady-state rheology flow experiments revealed that LNC exhibited shear thinning in different solutions,which decreased with increasing concentration.It has desirable solu-bility and dispersion in N,N-dimethylformamide(DMF)solvent.The effect of solvents on the entan-glement or orientation of LNC molecular chains may be reduced.These results can be quantitatively demonstrated using the Herschel-Bulkley model.Dynamic viscoelastic studies identified a critical point of concentration-frequency of 2.5 rad/s.This particular frequency point is a turning point in the law of the effect of concentration on the loss factor(tanδ).For gelatinized systems,increasing the solvent content reduces the temperature sensitivity of the gelatinized materials.The viscosity-temperature correlation based on the Arrhenius equation allowed the optimization of the solvent content through the derived equilibrium relationship.These structure-rheological performance relationships establish basic guidelines for the precision gelatinization of LNC-based propellant,provide theoretical support for the replacement of conventional NC by LNC,and guide the gelatinization process to improve the performance of gun propellants.
基金supported by the National Natural Science Foundation of China(Grant Nos.52172240)the Natural Science Foundation of Jiangsu Province of China(BK20240591)the General Project of Education Department of Jiangsu Province(24KJB480008)。
文摘Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the failure mechanism of conversion-alloy anodes is ascribed to volume expansion or the shuttle effect,which,however,fails to adequately explain their characteristic electrochemical behavior:an initial rapid drop and then a gradual decline in capacity.Herein,by combining electrochemical characterizations with multi-scale microscopies,spectroscopy,and theoretical calculations,we systematically analyze the failure mechanism of Bi_(2)Te_(3),a typical conversion-alloy anode.The failure processes and mechanisms are identified into two stages:(1)the rapid capacity fading dominated by the shuttle effect in the first several cycles and(2)the gradual material deactivation and capacity decline due to solid-electrolyte interphase accumulation in the following cycles.Furthermore,in response to these failure mechanisms,an elaborate design of Bi_(2)Te_(3)-based electrode featuring ultrafine nanoparticles and carbon encapsulation is presented,which exhibits prominent capability in avoiding the above negative effects and substantially enhancing cycling stability.This study reveals the failure mechanism of conversion-alloy anode throughout its entire life cycle,and the gained insight may lead to targeted optimization strategies for stable high-capacity electrodes.
基金Project supported by the National Natural Science Foundation of China(Nos.12132015,12332015,and 12302333)。
文摘This study investigates the motion behavior of a slender flexible particle in a backward-facing step(BFS)flow using the direct-forcing fictitious domain method,with a particular focus on the trapping phenomena near the separation vortex region.Three distinct motion modes are identified:periodic rotation or oscillation within the vortex(trapping),downstream transport(escape),and transition state exhibiting unstable trapping.A dynamic balance among inward migration,centrifugal effects,wall interactions,and elastic forces enables the particle to achieve stable orbital motion within two distinct limit cycles.The topology of these orbits is governed by parameters,including the aspect ratio,structural flexibility,deformation intensity,and fluid inertia,all of which are characterized by the Reynolds number(Re).Specifically,fluid inertia plays a dominant role in facilitating particle trapping.At a fixed Re,a particle with a smaller aspect ratio tends to migrate inward and become trapped,whereas one with a larger aspect ratio is more likely to escape.Structural flexibility,especially when enhanced by confinement near the wall,leads to elastic deformation that induces secondary vortices and a weak flipping motion.The deformation intensityαsignificantly influences the lateral migration of the slender particle after the initial release;a largerαcauses it to drift toward the channel centerline,increasing the probability of escape.These findings provide a theoretical foundation for optimizing the transport and capture of slender soft swimmers in complex flow environments.
基金financial supports from the National Natural Science Foundation of China(Grant No.62335006,62275065,624B2050,62022032,and 62405078)Open Subject of Hebei Key Laboratory of Advanced Laser Technology and Equipment(HBKL-ALTE2025001)+2 种基金Heilongjiang Postdoctoral Fund(Grant No.LBH-Z23144 and LBH-Z24155)Natural Science Foundation of Heilongjiang Province(Grant No.LH2024F031)China Postdoctoral Science Foundation(Grant No.2024M764172).
文摘In this paper,a fast step heterodyne light-induced thermoelastic spectroscopy(SH-LITES)sensor using a high-frequency quartz tuning fork(QTF)with resonant frequency of~100 kHz is reported for the first time.The theoretical principle of heterodyne LITES(H-LITES)signal generation is analyzed firstly,and an acetylene(C_(2)H_(2))H-LITES sensor is established to verify its performance.Experimental comparisons between the high-frequency QTF and a standard commercial QTF with resonant frequency of~32.768 kHz reveal that the high-frequency QTF exhibits a tenfold faster response time.Specifically,the H-LITES sensor with this QTF achieves a 33 ms measurement cycle,90%shorter than commercial counterparts.Furthermore,The SH-LITES technique is proposed to further shorten the scanning time to 15 ms,which achieves the shortest LITES measurement time known to date.To demonstrate its advantages in dynamic gas detection,an H_(2)O-LITES system integrating both QTF types is constructed for real-time monitoring of H_(2)O concentration during different respiration patterns.Comparative measurements show that the SH-LITES more accurately captures dynamic H_(2)O concentration fluctuations during respiration,outperforming the commercial QTF-based H-LITES sensor in rapid response scenarios.
基金supported by the National Hi-Tech R&D Program of China (No. 2012AA063202)National Key Project of Scientific and Technical Support Program of China (Nos. 2011BAE13B07, 2012BAC02B01, and 2011BAC10B02)National Natural Science Foundation of China (Nos. 51174247 and 50972013)
文摘The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.
