This paper discusses the importance of standards in the fire extinguishing agent industry,and highlights the vital role of the standards in promoting technological innovation.China’s standards for fire extinguishing ...This paper discusses the importance of standards in the fire extinguishing agent industry,and highlights the vital role of the standards in promoting technological innovation.China’s standards for fire extinguishing agent products have evolved significantly,aligning with industrial development,market demands,regulatory requirements,to respond to the great impact of international competition in the industry.The paper analyzes the current state of China’s standards,including their composition and integration with industry growth,green development strategies,and international harmonization.Future development strategies for the standards framework should focus on valid period estimation,fire test model development,and raw material selection guidelines.By implementing these strategies,China’s fire protection industry can enhance product quality,contribute to public safety,and maintain a competitive edge in the global market.展开更多
One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and ...One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.展开更多
Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety...Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.展开更多
Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity an...Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity and superparamagnetism.However,it is still a great challenge to prepare ideal iron oxide based contrast agents with high uniformity,excellent water solubility and biocompatibility.In this paper,a novel water-soluble polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(N-vinyl-2-pyrrolidone)(PTMP-PVP)was used as a capping reagent to prepare iron oxide nanoparticles MIONs@PTMP-PVP through one-step co-precipitation of iron precursors in aqueous solution at 100℃.The obtained nanoparticles MIONs@PTMP-PVP had a small size and narrow size distribution,and they were found to be biocompatible as determined through CCK-8 assay and histology analysis.In vivo MRI study demonstrated that the obtained MIONs@PTMP-PVP can be potentially used as an effective T_(2)-weighted MRI contrast agent.展开更多
Purpose: Formal concept analysis(FCA) and concept lattice theory(CLT) are introduced for constructing a network of IDR topics and for evaluating their effectiveness for knowledge structure exploration.Design/methodolo...Purpose: Formal concept analysis(FCA) and concept lattice theory(CLT) are introduced for constructing a network of IDR topics and for evaluating their effectiveness for knowledge structure exploration.Design/methodology/approach: We introduced the theory and applications of FCA and CLT, and then proposed a method for interdisciplinary knowledge discovery based on CLT. As an example of empirical analysis, interdisciplinary research(IDR) topics in Information & Library Science(LIS) and Medical Informatics, and in LIS and Geography-Physical, were utilized as empirical fields. Subsequently, we carried out a comparative analysis with two other IDR topic recognition methods.Findings: The CLT approach is suitable for IDR topic identification and predictions.Research limitations: IDR topic recognition based on the CLT is not sensitive to the interdisciplinarity of topic terms, since the data can only reflect whether there is a relationship between the discipline and the topic terms. Moreover, the CLT cannot clearly represent a large amounts of concepts.Practical implications: A deeper understanding of the IDR topics was obtained as the structural and hierarchical relationships between them were identified, which can help to get more precise identification and prediction to IDR topics.Originality/value: IDR topics identification based on CLT have performed well and this theory has several advantages for identifying and predicting IDR topics. First, in a concept lattice, there is a partial order relation between interconnected nodes, and consequently, a complete concept lattice can present hierarchical properties. Second, clustering analysis of IDR topics based on concept lattices can yield clusters that highlight the essential knowledge features and help display the semantic relationship between different IDR topics. Furthermore, the Hasse diagram automatically displays all the IDR topics associated with the different disciplines, thus forming clusters of specific concepts and visually retaining and presenting the associations of IDR topics through multiple inheritance relationships between the concepts.展开更多
Purpose–The purpose of this study is to address the deficiency in safety monitoring technology for 27.5 kV high-voltage cables within the railway traction power supply by analyzing the grounding methods employed in h...Purpose–The purpose of this study is to address the deficiency in safety monitoring technology for 27.5 kV high-voltage cables within the railway traction power supply by analyzing the grounding methods employed in high-speed railways and developing an effective monitoring solution.Design/methodology/approach–Through establishing a mathematical model of induced potential in the cable sheath and analyzing its influencing factors,the principle of grounding current monitoring is proposed.Furthermore,the accuracy of data collection and alarm function of the monitoring equipment were verified through laboratory simulation experiments.Finally,through practical application in the traction substation of the railway bureau on site,a large amount of data were collected to verify the stability and reliability of the monitoring system in actual environments.Findings–The experimental results show that the designed monitoring system can effectively monitor the grounding current of high-voltage cables and respond promptly to changes in cable insulation status.The system performs excellently in terms of data collection accuracy,real-time performance and reliability of alarm functions.In addition,the on-site trial results further confirm the accuracy and reliability of the monitoring system in practical applications,providing strong technical support for the safe operation of highspeed railway traction power supply systems.Originality/value–This study innovatively develops a 27.5kV high-voltage cable grounding current monitoring system,which provides a new technical means for evaluating the insulation status of cables by accurately measuring the grounding current.The design,experimental verification and application of this system in high-speed railway traction power supply systems have demonstrated significant academic value and practical significance,contributing innovative solutions to the field of railway power supply safety monitoring.展开更多
At this stage, China's social economy is growing steadily, and the power industry is gradually strengthened. Since most of the power generation of the hydropower station is completed by operating the hydropower un...At this stage, China's social economy is growing steadily, and the power industry is gradually strengthened. Since most of the power generation of the hydropower station is completed by operating the hydropower unit, if there is a problem or fault, the hydropower unit is easy to seriously affect the power generation of the hydropower station. Due to the long operation time of hydro generator, the fault is imminent. In order to minimize a series of losses caused by such faults, relevant technicians shall identify and clarify common faults, inspect and maintain these faults and problems, and effectively improve the safety and stability of hydraulic units.展开更多
Solar Design(https://solardesign.cn/)is an online photovoltaic device simulation and design platform that provides engineering modeling analysis for crystalline silicon solar cells,as well as emerging high-efficiency ...Solar Design(https://solardesign.cn/)is an online photovoltaic device simulation and design platform that provides engineering modeling analysis for crystalline silicon solar cells,as well as emerging high-efficiency solar cells such as organic,perovskite,and tandem cells.The platform offers user-updatable libraries of basic photovoltaic materials and devices,device-level multi-physics simulations involving optical–electrical–thermal interactions,and circuit-level compact model simulations based on detailed balance theory.Employing internationally advanced numerical methods,the platform accurately,rapidly,and efficiently solves optical absorption,electrical transport,and compact circuit models.It achieves multi-level photovoltaic simulation technology from“materials to devices to circuits”with fully independent intellectual property rights.Compared to commercial softwares,the platform achieves high accuracy and improves speed by more than an order of magnitude.Additionally,it can simulate unique electrical transport processes in emerging solar cells,such as quantum tunneling,exciton dissociation,and ion migration.展开更多
[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hyd...[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hydrophobicity of Me-4PACz presents a critical challenge for the fabrication of high-quality perovskite films due to its poor wettability.Here,a doped Al_(2)O_(3)with Me-4PACz to modify the Me-4PACz surface was proposed.On one hand,this approach improved the wettability of the Me-4PACz film,enhancing the coverage,uniformity,and buried interface properties of the perovskite film.On the other hand,compared to Al_(2)O_(3)modification alone,doping Al_(2)O_(3)with Me-4PACz allowed direct contact between the perovskite and Me-4PACz,resulting in better buried interface passivation.As a result,we achieved an efficiency of 22.71%for single-junction wide-bandgap perovskite solar cells(1.68 eV).Additionally,the efficiency of perovskite/silicon tandem solar cells was improved from 28.68%to 30.92%,with a significant reduction in hysteresis.Furthermore,the tandem cells demonstrated no degradation after 4200 s of operation at the maximum power point.展开更多
Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hyd...Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hydraulic fracturing,primarily controlled by in situ stress,fail to connect directionally with the target well.This study proposes a novel stimulation method,i.e.radial borehole fracturing,which shows great potential for guiding the directional propagation of fractures.The fracture initiation and propagation behaviors of high-temperature granite under radial borehole fracturing are investigated and compared with those of conventional fracturing.Three-dimensional morphological scanning and reinjection tests are used to quantitatively evaluate fracturing performance.Additionally,the influences of key parameters,including rock temperature,in situ stress,injection rate,fluid viscosity,azimuth of the radial borehole,and the number of radial boreholes on the fracture morphology and breakdown pressure are investigated.The results show that radial borehole fracturing can effectively guide the initiation and propagation of fractures along the radial borehole.The breakdown pressure of radial borehole fracturing can be reduced by 14.1%–43.7%compared to conventional fracturing.A higher fluid-rock temperature difference reduces the directional propagation range of fractures guided by the radial borehole.Increases in the vertical density of radial boreholes,injection rate,and fluid viscosity enhance the guiding ability of radial boreholes.Furthermore,there is a competitive relationship between in situ stress and the azimuth of radial boreholes in controlling fracture propagation.This research provides a viable alternative for the directional connection of injection-production wells in HDR reservoirs.展开更多
A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)...A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.展开更多
Multimodal ultrasonic vibration(UV)assisted micro-forming has been widely investigated for its advantages of further reducing forming loads and improving forming quality.However,the influence mechanism of different UV...Multimodal ultrasonic vibration(UV)assisted micro-forming has been widely investigated for its advantages of further reducing forming loads and improving forming quality.However,the influence mechanism of different UV modes on microstructure evolution and mechanical properties was still unclear.Mul-timodal UV assisted micro-compression tests on T2 copper with different grains and sample sizes were conducted in this study.The microstructure evolution for different UV modes was observed by EBSD.The results showed that the true stress reduction caused by UV was increased sequentially with tool ultrasonic vibration(TV),mold ultrasonic vibration(MV)and compound ultrasonic vibration(CV).The region of grain deformation was shifted along the direction of UV,and the MV promoted the uniform distribution of deformation stress.The grain refinement,fiber streamline density,grain deformation and rotation degree were further enhanced under CV,due to the synergistic effect of TV and MV.Additionally,a coupled theoretical model considering both acoustic softening effect and size effect was proposed for describing the mechanical properties.And a physical model of dislocation motion in different UV modes was developed for describing the microstructure evolution.The maximum error between the theoretical and experimental results was only 2.39%.This study provides a theoretical basis for the optimization of UV assisted micro-forming process.展开更多
The dissolvable polysulfides and sluggish Li_2S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur(Li-S)batteries.Herein,we introduce a dual-doping strategy to modulat...The dissolvable polysulfides and sluggish Li_2S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur(Li-S)batteries.Herein,we introduce a dual-doping strategy to modulate the electronic structure of MoS_(2),thereby obtaining a multifunctional catalyst that serves as an efficient sulfur host.The W/V dual single-atomdoped MoS_(2)grown on carbon nanofibers(CMWVS)demonstrates a strong adsorption ability for lithium polysulfides,suppressing the shuttle effects.Additionally,the doping process also results in the phase transition from 2H-MoS_(2)to 1T-MoS_(2)and generates sufficient edge sulfur atoms,promoting the charge/electron transfer and enriching the reaction sites.All these merits contribute to the superior conversion reaction kinetics,leading to the outstanding Li-S battery performance.When fabricated as cathodes by compositing with sulfur,the CMWVS/S cathode delivers a high capacity of 1481.7 mAh g^(-1)at 0.1 C(1 C=1672 mAh g^(-1))and maintains 816.3 m Ah g^(-1)after 1000 cycles at 1.0 C,indicating outstanding cycling stability.Even under a high sulfur loading of 7.9 mg cm^(-2)and lean electrolyte conditions(E/S ratio of 9.0μL mg^(-1)),the cathode achieves a high areal capacity of 8.2 m Ah cm^(-2),showing great promise for practical Li-S battery applications.This work broadens the scope of doping strategies in transition-metal dichalcogenides by tailoring their electronic structures,providing insightful direction for the rational development of high-efficiency electrocatalysts for advanced Li-S battery applications.展开更多
Liver is a vital organ in the human body and plays a central role in the metabolism and detoxification of endotoxins and exotoxins.Bilirubin is an endotoxin derived from hemoglobin(Hb).Removing excess bilirubin in the...Liver is a vital organ in the human body and plays a central role in the metabolism and detoxification of endotoxins and exotoxins.Bilirubin is an endotoxin derived from hemoglobin(Hb).Removing excess bilirubin in the blood is crucial for the treatment of liver diseases.Hemoperfusion,which relies on adsorbents to efficiently adsorb toxins,is a widely applied procedure for the removal of blood toxins.To broaden and improve the range and performance of hemoperfusion adsorbents,we synthesized cationic hyper crosslinked polymers(HCPs)with strong affinity for bilirubin.This material exhibited outstanding adsorption performance,with a maximum adsorption capacity of 934 mg/g and a removal efficiency of 96%.Further investigation confirmed their excellent selectivity,reusability,and biocompatibility.These findings expand the potential applications of HCPs and provide insight into strategies for constructing promising hemoperfusion adsorbent materials.展开更多
Flexible and wearable sensors offer immense potential for rehabilitation medicine,but most rely solely on electrical signals,lacking real-time visual feedback and limiting trainee's interactivity.Inspired by the s...Flexible and wearable sensors offer immense potential for rehabilitation medicine,but most rely solely on electrical signals,lacking real-time visual feedback and limiting trainee's interactivity.Inspired by the structural coloration of Cyanocitta stelleri feathers,we developed a dual-mode sensor by utilizing black conductive polymer hydrogel(CPH)-enhanced structural color strategy.This sensor integrates a hydroxypropyl cellulose(HPC)-based structural color interface with a designed CPH sensing component.Highly visible light-absorbing CPH(absorption rate>88%)serves as the critical substrate for enhancing structural color performance.By absorbing incoherent scattered light and suppressing background interference,it significantly enhances the saturation of structural color,thereby achieving a high contrast index of 4.92.Unlike the faint and hardly visible structural colors on non-black substrates,the HPC on CPH displays vivid,highly perceptible colors and desirable mechanochromic behavior.Moreover,the CPH acts as a flexible sensing element,fortified by hydrogen and coordination bond networks,and exhibits exceptional electromechanical properties,including 867.1 kPa tensile strength,strain sensitivity(gauge factor of 4.24),and outstanding durability(over 4400 cycles).Compared to traditional single-mode sensors,the integrated sensor provides real-time visual and digital dual feedback,enhancing the accuracy and interactivity of rehabilitation assessments.This technology holds promise for advancing next-generation rehabilitation medicine.展开更多
SO2 poisoning and regeneration of Mn-Ce/TiO2 catalyst prepared by a novel co-precipitation method for low temperature selective catalytic reduction （SCR） of NOx with ammonia were investigated in this study. When 700...SO2 poisoning and regeneration of Mn-Ce/TiO2 catalyst prepared by a novel co-precipitation method for low temperature selective catalytic reduction （SCR） of NOx with ammonia were investigated in this study. When 700 ppm SO2 was fed in, the Mn-Ce/TiO2 catalyst had good resistance to SO2, but the deactivation of Mn-Ce/TiO2 poisoned by SO2 still occurred. The NO conversion of Mn-Ce/TiO2 （the molar ra-tio of Ce to Ti is 0.075） catalyst decreased from 92.5% to 34.6% in 13 h. Characterizations of fresh and SO2-poisoned Mn-Ce/TiO2 catalysts were carried out by Brunauer-Emmett-Teller method （BET）, ion chromatography （IC）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD）. The characterized results indicated that the deposition of sulfates and nitrates on the surface made the catalyst deactivated. Water washing, thermal regeneration and reductive regeneration were used to regenerate the deactivated Mn-Ce/TiO2. And water washing showed best performance on the regeneration of poisoned catalysts, especially with ultrasonic vibration. The Mn-Ce/TiO2 catalyst showed high stability under a series of deactivation-regeneration experiments for ten cycles.展开更多
Shijiazhuang,the city with the worst air quality in China,is suffering from severe ozone pollution in summer.As the key precursors of ozone generation,it is necessary to control the Volatile Organic Compounds(VOCs)pol...Shijiazhuang,the city with the worst air quality in China,is suffering from severe ozone pollution in summer.As the key precursors of ozone generation,it is necessary to control the Volatile Organic Compounds(VOCs)pollution.To have a better understanding of the pollution status and source contribution,the concentrations of 117 ambient VOCs were analyzed from April to August 2018 in an urban site in Shijiazhuang.Results showed that the monthly average concentration of total VOCs was 66.27 ppbv,in which,the oxygenated VOCs(37.89%),alkanes(33.89%),and halogenated hydrocarbons(13.31%)were the main composite on.Eight major sources were identified using Positive Matrix Factorization modeling with an accurate VOCs emission inventory as inter-complementary methods revealed that the petrochemical industry(26.24%),other industrial sources(15.19%),and traffic source(12.24%)were the major sources for ambient VOCs in Shijiazhuang.The spatial distributions of major industrial activities emissions were identified by using geographic information statistics system,which illustrated the VOCs was mainly from the north and southeast of Shijiazhuang.The inverse trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)and Potential Source Contribution Function(PSCF)clearly demonstrated the features of pollutant transport to Shijiazhuang.These findings can provide references for local governments regarding control strategies to reduce VOCs emissions.展开更多
Litchi(Litchi chinensis Sonn.)and longan(Dimocarpus longan Lour.)fruits have a succulent and white aril with a brown seed and are becoming popular worldwide.The two fruits have been used in traditional Chinese medicin...Litchi(Litchi chinensis Sonn.)and longan(Dimocarpus longan Lour.)fruits have a succulent and white aril with a brown seed and are becoming popular worldwide.The two fruits have been used in traditional Chinese medicine as popular herbs in the treatment of neural pain,swelling,and cardiovascular disease.The pericarp and seed portions as the by-products of litchi and longan fruits are estimated to be approximately 30%of the dry weight of the whole fruit and are rich in bioactive constituents.In the recent years,many biological activities,such as tyrosinase inhibitory,antioxidant,anti-inflammatory,immunomodulatory,anti-glycated,and anti-cancer activities,as well as memory-increasing effects,have been reported for the litchi and longan pericarp and seed extracts,indicating a potentially significant contribution to human health.With the increasing production of litchi and longan fruits,enhanced utilization of the two fruit by-products for their inherent bioactive constituents in relation to pharmacological effects is urgently needed.This paper reviews the current advances in the extraction,processing,identification,and biological and pharmacological activities of constituents from litchi and longan by-products.Potential utilization of litchi and longan pericarps and seeds in relation to further research is also discussed.展开更多
It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight...It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.展开更多
Niobium oxide as the promoter was doped in the V/WTi catalyst for the selective catalytic reduction（SCR）of NO.The results showed that the addition of Nb2O5could improve the SCR activity at low temperatures and the 6...Niobium oxide as the promoter was doped in the V/WTi catalyst for the selective catalytic reduction（SCR）of NO.The results showed that the addition of Nb2O5could improve the SCR activity at low temperatures and the 6 wt.%additive was an appropriate dosage.The enhanced reaction activity of adsorbed ammonia species and the improved dispersion of vanadium oxide might be the reasons for the elevation of SCR activity at low temperatures.The resistances to SO2of 3V6Nb/WTi catalyst at different temperatures were investigated.FTIR spectrum and TG-FTIR result indicated that the deposition of ammonium sulfate species was the main deactivation reason at low temperatures,which still exhibited the reactivity with NO above 200℃ on the catalyst surface.There was a synergistic effect among NH3,H2O and SO2that NH3and H2O both accelerated the catalyst deactivation in the presence of SO2at 175℃.The thermal treatment at 400℃ could regenerate the deactivated catalyst and get SCR activity recovered.The particle and monolith catalysts both kept stable NOxconversion at 225℃ with high concentration of H2O and SO2during the long time tests.展开更多
基金supported by the specialized fund project for the fundamental research operation of central-level public welfare scientific research institutes,titled“Research on the International Standards System Construction and Updates in the Field of Fire Protection(Project No.2023SJ09)”.
文摘This paper discusses the importance of standards in the fire extinguishing agent industry,and highlights the vital role of the standards in promoting technological innovation.China’s standards for fire extinguishing agent products have evolved significantly,aligning with industrial development,market demands,regulatory requirements,to respond to the great impact of international competition in the industry.The paper analyzes the current state of China’s standards,including their composition and integration with industry growth,green development strategies,and international harmonization.Future development strategies for the standards framework should focus on valid period estimation,fire test model development,and raw material selection guidelines.By implementing these strategies,China’s fire protection industry can enhance product quality,contribute to public safety,and maintain a competitive edge in the global market.
文摘One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.
文摘Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.
基金financially supported by the International Cooperation Program from the Ministry of Science and Technology of Hubei Province(No.2023EHA069)Shenzhen Science and Technology Program(No.JCYJ20230807143702005)National Foreign Experts Program(No.G2022027015L)。
文摘Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity and superparamagnetism.However,it is still a great challenge to prepare ideal iron oxide based contrast agents with high uniformity,excellent water solubility and biocompatibility.In this paper,a novel water-soluble polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(N-vinyl-2-pyrrolidone)(PTMP-PVP)was used as a capping reagent to prepare iron oxide nanoparticles MIONs@PTMP-PVP through one-step co-precipitation of iron precursors in aqueous solution at 100℃.The obtained nanoparticles MIONs@PTMP-PVP had a small size and narrow size distribution,and they were found to be biocompatible as determined through CCK-8 assay and histology analysis.In vivo MRI study demonstrated that the obtained MIONs@PTMP-PVP can be potentially used as an effective T_(2)-weighted MRI contrast agent.
基金an outcome of the project "Study on the Recognition Method of Innovative Evolving Trajectory based on Topic Correlation Analysis of Science and Technology" (No. 71704170) supported by National Natural Science Foundation of Chinathe project "Study on Regularity and Dynamics of Knowledge Diffusion among Scientific Disciplines" (No. 71704063) supported by National Natura Science Foundation of Chinathe Youth Innovation Promotion Association, CAS (Grant No. 2016159)
文摘Purpose: Formal concept analysis(FCA) and concept lattice theory(CLT) are introduced for constructing a network of IDR topics and for evaluating their effectiveness for knowledge structure exploration.Design/methodology/approach: We introduced the theory and applications of FCA and CLT, and then proposed a method for interdisciplinary knowledge discovery based on CLT. As an example of empirical analysis, interdisciplinary research(IDR) topics in Information & Library Science(LIS) and Medical Informatics, and in LIS and Geography-Physical, were utilized as empirical fields. Subsequently, we carried out a comparative analysis with two other IDR topic recognition methods.Findings: The CLT approach is suitable for IDR topic identification and predictions.Research limitations: IDR topic recognition based on the CLT is not sensitive to the interdisciplinarity of topic terms, since the data can only reflect whether there is a relationship between the discipline and the topic terms. Moreover, the CLT cannot clearly represent a large amounts of concepts.Practical implications: A deeper understanding of the IDR topics was obtained as the structural and hierarchical relationships between them were identified, which can help to get more precise identification and prediction to IDR topics.Originality/value: IDR topics identification based on CLT have performed well and this theory has several advantages for identifying and predicting IDR topics. First, in a concept lattice, there is a partial order relation between interconnected nodes, and consequently, a complete concept lattice can present hierarchical properties. Second, clustering analysis of IDR topics based on concept lattices can yield clusters that highlight the essential knowledge features and help display the semantic relationship between different IDR topics. Furthermore, the Hasse diagram automatically displays all the IDR topics associated with the different disciplines, thus forming clusters of specific concepts and visually retaining and presenting the associations of IDR topics through multiple inheritance relationships between the concepts.
基金the China Railway Wuhan Bureau Group Co.,Ltd.under the 2023 Science and Technology Research and Development Plan(Second Batch)(Wuhan Railway Science and Information Letter[2023]No.269),classification code 23GD07.
文摘Purpose–The purpose of this study is to address the deficiency in safety monitoring technology for 27.5 kV high-voltage cables within the railway traction power supply by analyzing the grounding methods employed in high-speed railways and developing an effective monitoring solution.Design/methodology/approach–Through establishing a mathematical model of induced potential in the cable sheath and analyzing its influencing factors,the principle of grounding current monitoring is proposed.Furthermore,the accuracy of data collection and alarm function of the monitoring equipment were verified through laboratory simulation experiments.Finally,through practical application in the traction substation of the railway bureau on site,a large amount of data were collected to verify the stability and reliability of the monitoring system in actual environments.Findings–The experimental results show that the designed monitoring system can effectively monitor the grounding current of high-voltage cables and respond promptly to changes in cable insulation status.The system performs excellently in terms of data collection accuracy,real-time performance and reliability of alarm functions.In addition,the on-site trial results further confirm the accuracy and reliability of the monitoring system in practical applications,providing strong technical support for the safe operation of highspeed railway traction power supply systems.Originality/value–This study innovatively develops a 27.5kV high-voltage cable grounding current monitoring system,which provides a new technical means for evaluating the insulation status of cables by accurately measuring the grounding current.The design,experimental verification and application of this system in high-speed railway traction power supply systems have demonstrated significant academic value and practical significance,contributing innovative solutions to the field of railway power supply safety monitoring.
文摘At this stage, China's social economy is growing steadily, and the power industry is gradually strengthened. Since most of the power generation of the hydropower station is completed by operating the hydropower unit, if there is a problem or fault, the hydropower unit is easy to seriously affect the power generation of the hydropower station. Due to the long operation time of hydro generator, the fault is imminent. In order to minimize a series of losses caused by such faults, relevant technicians shall identify and clarify common faults, inspect and maintain these faults and problems, and effectively improve the safety and stability of hydraulic units.
基金Project supported by the Scientific Research Project of China Three Gorges Corporation(Grant No.202203092)。
文摘Solar Design(https://solardesign.cn/)is an online photovoltaic device simulation and design platform that provides engineering modeling analysis for crystalline silicon solar cells,as well as emerging high-efficiency solar cells such as organic,perovskite,and tandem cells.The platform offers user-updatable libraries of basic photovoltaic materials and devices,device-level multi-physics simulations involving optical–electrical–thermal interactions,and circuit-level compact model simulations based on detailed balance theory.Employing internationally advanced numerical methods,the platform accurately,rapidly,and efficiently solves optical absorption,electrical transport,and compact circuit models.It achieves multi-level photovoltaic simulation technology from“materials to devices to circuits”with fully independent intellectual property rights.Compared to commercial softwares,the platform achieves high accuracy and improves speed by more than an order of magnitude.Additionally,it can simulate unique electrical transport processes in emerging solar cells,such as quantum tunneling,exciton dissociation,and ion migration.
基金supported by the National Key Research and Development Program of China(2023YFB4202503)the cooperation project between Three Gorges Corporation and Nankai University(202103571)+6 种基金the National Natural Science Foundation Joint Fund(U21A2072)the National Science Foundation(62274099,62104115)Tianjin Science and Technology Project(24ZXZSSS00160)Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202302A0370009)the China Higher Education Discipline Innovation Overseas Expert Introduction Project(B16027)the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central Universities,Nankai University。
文摘[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hydrophobicity of Me-4PACz presents a critical challenge for the fabrication of high-quality perovskite films due to its poor wettability.Here,a doped Al_(2)O_(3)with Me-4PACz to modify the Me-4PACz surface was proposed.On one hand,this approach improved the wettability of the Me-4PACz film,enhancing the coverage,uniformity,and buried interface properties of the perovskite film.On the other hand,compared to Al_(2)O_(3)modification alone,doping Al_(2)O_(3)with Me-4PACz allowed direct contact between the perovskite and Me-4PACz,resulting in better buried interface passivation.As a result,we achieved an efficiency of 22.71%for single-junction wide-bandgap perovskite solar cells(1.68 eV).Additionally,the efficiency of perovskite/silicon tandem solar cells was improved from 28.68%to 30.92%,with a significant reduction in hysteresis.Furthermore,the tandem cells demonstrated no degradation after 4200 s of operation at the maximum power point.
基金supported by the National Science Fund of China for Major International(Regional)Joint Research Project(Grant No.52020105001)the National Natural Science Foundation of China(Grant Nos.52304053 and 52204019).
文摘Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hydraulic fracturing,primarily controlled by in situ stress,fail to connect directionally with the target well.This study proposes a novel stimulation method,i.e.radial borehole fracturing,which shows great potential for guiding the directional propagation of fractures.The fracture initiation and propagation behaviors of high-temperature granite under radial borehole fracturing are investigated and compared with those of conventional fracturing.Three-dimensional morphological scanning and reinjection tests are used to quantitatively evaluate fracturing performance.Additionally,the influences of key parameters,including rock temperature,in situ stress,injection rate,fluid viscosity,azimuth of the radial borehole,and the number of radial boreholes on the fracture morphology and breakdown pressure are investigated.The results show that radial borehole fracturing can effectively guide the initiation and propagation of fractures along the radial borehole.The breakdown pressure of radial borehole fracturing can be reduced by 14.1%–43.7%compared to conventional fracturing.A higher fluid-rock temperature difference reduces the directional propagation range of fractures guided by the radial borehole.Increases in the vertical density of radial boreholes,injection rate,and fluid viscosity enhance the guiding ability of radial boreholes.Furthermore,there is a competitive relationship between in situ stress and the azimuth of radial boreholes in controlling fracture propagation.This research provides a viable alternative for the directional connection of injection-production wells in HDR reservoirs.
基金supported by the Science and Technology Development Fund(FDCT),Macao SAR(No.0149/2022/A),and(No.0046/2024/AFJ)Guangdong Science and Technology Department(No.2023QN10C305)。
文摘A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.
基金supported by the National Key Research and Development Program(No.2022YFB4602502)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011991)+2 种基金the Key Research and Development Program Fund of Hubei Province(No.2022BAA057)the state Key Lab-oratory of Solidification Processing in NPU(No.SKLSP202325)the China Scholarship Council Visiting PhD Program(No.202306410136).
文摘Multimodal ultrasonic vibration(UV)assisted micro-forming has been widely investigated for its advantages of further reducing forming loads and improving forming quality.However,the influence mechanism of different UV modes on microstructure evolution and mechanical properties was still unclear.Mul-timodal UV assisted micro-compression tests on T2 copper with different grains and sample sizes were conducted in this study.The microstructure evolution for different UV modes was observed by EBSD.The results showed that the true stress reduction caused by UV was increased sequentially with tool ultrasonic vibration(TV),mold ultrasonic vibration(MV)and compound ultrasonic vibration(CV).The region of grain deformation was shifted along the direction of UV,and the MV promoted the uniform distribution of deformation stress.The grain refinement,fiber streamline density,grain deformation and rotation degree were further enhanced under CV,due to the synergistic effect of TV and MV.Additionally,a coupled theoretical model considering both acoustic softening effect and size effect was proposed for describing the mechanical properties.And a physical model of dislocation motion in different UV modes was developed for describing the microstructure evolution.The maximum error between the theoretical and experimental results was only 2.39%.This study provides a theoretical basis for the optimization of UV assisted micro-forming process.
基金supported by the National Natural Science Foundation of China(52402166)the Science and Technology Development Fund+2 种基金Macao SAR(0065/2023/AFJ,0116/2022/A3)the Australian Research Council(DE220100154)the Natural Science Foundation of Guangdong Province(2025A1515011120)。
文摘The dissolvable polysulfides and sluggish Li_2S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur(Li-S)batteries.Herein,we introduce a dual-doping strategy to modulate the electronic structure of MoS_(2),thereby obtaining a multifunctional catalyst that serves as an efficient sulfur host.The W/V dual single-atomdoped MoS_(2)grown on carbon nanofibers(CMWVS)demonstrates a strong adsorption ability for lithium polysulfides,suppressing the shuttle effects.Additionally,the doping process also results in the phase transition from 2H-MoS_(2)to 1T-MoS_(2)and generates sufficient edge sulfur atoms,promoting the charge/electron transfer and enriching the reaction sites.All these merits contribute to the superior conversion reaction kinetics,leading to the outstanding Li-S battery performance.When fabricated as cathodes by compositing with sulfur,the CMWVS/S cathode delivers a high capacity of 1481.7 mAh g^(-1)at 0.1 C(1 C=1672 mAh g^(-1))and maintains 816.3 m Ah g^(-1)after 1000 cycles at 1.0 C,indicating outstanding cycling stability.Even under a high sulfur loading of 7.9 mg cm^(-2)and lean electrolyte conditions(E/S ratio of 9.0μL mg^(-1)),the cathode achieves a high areal capacity of 8.2 m Ah cm^(-2),showing great promise for practical Li-S battery applications.This work broadens the scope of doping strategies in transition-metal dichalcogenides by tailoring their electronic structures,providing insightful direction for the rational development of high-efficiency electrocatalysts for advanced Li-S battery applications.
基金financially supported by the International Cooperation Program of the Ministry of Science and Technology of Hubei Province(No.2023EHA069)Shenzhen Science and Technology Program(No.JCYJ20230807143702005)the National Foreign Experts Program(No.G2022027015L)。
文摘Liver is a vital organ in the human body and plays a central role in the metabolism and detoxification of endotoxins and exotoxins.Bilirubin is an endotoxin derived from hemoglobin(Hb).Removing excess bilirubin in the blood is crucial for the treatment of liver diseases.Hemoperfusion,which relies on adsorbents to efficiently adsorb toxins,is a widely applied procedure for the removal of blood toxins.To broaden and improve the range and performance of hemoperfusion adsorbents,we synthesized cationic hyper crosslinked polymers(HCPs)with strong affinity for bilirubin.This material exhibited outstanding adsorption performance,with a maximum adsorption capacity of 934 mg/g and a removal efficiency of 96%.Further investigation confirmed their excellent selectivity,reusability,and biocompatibility.These findings expand the potential applications of HCPs and provide insight into strategies for constructing promising hemoperfusion adsorbent materials.
基金supported by the Science and Technology Development Fund,Macao SAR(0065/2023/AFJ,0116/2022/A3)the National Natural Science Foundation of China(52402166)+4 种基金the Natural Science Foundation of Guangdong Province(2025A1515011120)the Australian Research Council(DE220100154)the financial support from the Science and Technology Development Fund(FDCT),Macao SAR(No.0149/2022/A),and(No.0046/2024/AFJ)Guangdong Science and Technology Department(2023QN10C305)for this workthe financial support from the National Natural Science Foundation of China(Grant No.22305185)。
文摘Flexible and wearable sensors offer immense potential for rehabilitation medicine,but most rely solely on electrical signals,lacking real-time visual feedback and limiting trainee's interactivity.Inspired by the structural coloration of Cyanocitta stelleri feathers,we developed a dual-mode sensor by utilizing black conductive polymer hydrogel(CPH)-enhanced structural color strategy.This sensor integrates a hydroxypropyl cellulose(HPC)-based structural color interface with a designed CPH sensing component.Highly visible light-absorbing CPH(absorption rate>88%)serves as the critical substrate for enhancing structural color performance.By absorbing incoherent scattered light and suppressing background interference,it significantly enhances the saturation of structural color,thereby achieving a high contrast index of 4.92.Unlike the faint and hardly visible structural colors on non-black substrates,the HPC on CPH displays vivid,highly perceptible colors and desirable mechanochromic behavior.Moreover,the CPH acts as a flexible sensing element,fortified by hydrogen and coordination bond networks,and exhibits exceptional electromechanical properties,including 867.1 kPa tensile strength,strain sensitivity(gauge factor of 4.24),and outstanding durability(over 4400 cycles).Compared to traditional single-mode sensors,the integrated sensor provides real-time visual and digital dual feedback,enhancing the accuracy and interactivity of rehabilitation assessments.This technology holds promise for advancing next-generation rehabilitation medicine.
基金financially supported by the Research Project of China Guodian Corporation (No.D11T22)
文摘SO2 poisoning and regeneration of Mn-Ce/TiO2 catalyst prepared by a novel co-precipitation method for low temperature selective catalytic reduction （SCR） of NOx with ammonia were investigated in this study. When 700 ppm SO2 was fed in, the Mn-Ce/TiO2 catalyst had good resistance to SO2, but the deactivation of Mn-Ce/TiO2 poisoned by SO2 still occurred. The NO conversion of Mn-Ce/TiO2 （the molar ra-tio of Ce to Ti is 0.075） catalyst decreased from 92.5% to 34.6% in 13 h. Characterizations of fresh and SO2-poisoned Mn-Ce/TiO2 catalysts were carried out by Brunauer-Emmett-Teller method （BET）, ion chromatography （IC）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD）. The characterized results indicated that the deposition of sulfates and nitrates on the surface made the catalyst deactivated. Water washing, thermal regeneration and reductive regeneration were used to regenerate the deactivated Mn-Ce/TiO2. And water washing showed best performance on the regeneration of poisoned catalysts, especially with ultrasonic vibration. The Mn-Ce/TiO2 catalyst showed high stability under a series of deactivation-regeneration experiments for ten cycles.
基金supported by the Hebei Provincial Depart-ment of Science and Technology(No.19273711D)the Min-istry of Education of the People’s Republic of China(No.CXZJHZ201717)+2 种基金the Shijiazhuang Science and Technology Bu-reau(No.191240273A,201240363A)the five fund platform projects of Hebei University of Science and Technology(No.1182210)the National Natural Science Foundation of China(No.21776059)。
文摘Shijiazhuang,the city with the worst air quality in China,is suffering from severe ozone pollution in summer.As the key precursors of ozone generation,it is necessary to control the Volatile Organic Compounds(VOCs)pollution.To have a better understanding of the pollution status and source contribution,the concentrations of 117 ambient VOCs were analyzed from April to August 2018 in an urban site in Shijiazhuang.Results showed that the monthly average concentration of total VOCs was 66.27 ppbv,in which,the oxygenated VOCs(37.89%),alkanes(33.89%),and halogenated hydrocarbons(13.31%)were the main composite on.Eight major sources were identified using Positive Matrix Factorization modeling with an accurate VOCs emission inventory as inter-complementary methods revealed that the petrochemical industry(26.24%),other industrial sources(15.19%),and traffic source(12.24%)were the major sources for ambient VOCs in Shijiazhuang.The spatial distributions of major industrial activities emissions were identified by using geographic information statistics system,which illustrated the VOCs was mainly from the north and southeast of Shijiazhuang.The inverse trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)and Potential Source Contribution Function(PSCF)clearly demonstrated the features of pollutant transport to Shijiazhuang.These findings can provide references for local governments regarding control strategies to reduce VOCs emissions.
基金supported by the National Natural Science Foundation of China(No.31770726)the National Key Research and Development Program of China(No.2016YFD0400904)
文摘Litchi(Litchi chinensis Sonn.)and longan(Dimocarpus longan Lour.)fruits have a succulent and white aril with a brown seed and are becoming popular worldwide.The two fruits have been used in traditional Chinese medicine as popular herbs in the treatment of neural pain,swelling,and cardiovascular disease.The pericarp and seed portions as the by-products of litchi and longan fruits are estimated to be approximately 30%of the dry weight of the whole fruit and are rich in bioactive constituents.In the recent years,many biological activities,such as tyrosinase inhibitory,antioxidant,anti-inflammatory,immunomodulatory,anti-glycated,and anti-cancer activities,as well as memory-increasing effects,have been reported for the litchi and longan pericarp and seed extracts,indicating a potentially significant contribution to human health.With the increasing production of litchi and longan fruits,enhanced utilization of the two fruit by-products for their inherent bioactive constituents in relation to pharmacological effects is urgently needed.This paper reviews the current advances in the extraction,processing,identification,and biological and pharmacological activities of constituents from litchi and longan by-products.Potential utilization of litchi and longan pericarps and seeds in relation to further research is also discussed.
基金supported by National Natural Science Foundation of China(Grant No.61075099)
文摘It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.
基金supported by the Policy-induced Project of Jiangsu Province for the Industry-University-Research Cooperation (No. BY2015070-21)the project was also supported by National Science and Technology Ministry (No. 2015BAA05B01)the Natural Science Fund Program of Jiangsu Province (No. BK20150749)
文摘Niobium oxide as the promoter was doped in the V/WTi catalyst for the selective catalytic reduction（SCR）of NO.The results showed that the addition of Nb2O5could improve the SCR activity at low temperatures and the 6 wt.%additive was an appropriate dosage.The enhanced reaction activity of adsorbed ammonia species and the improved dispersion of vanadium oxide might be the reasons for the elevation of SCR activity at low temperatures.The resistances to SO2of 3V6Nb/WTi catalyst at different temperatures were investigated.FTIR spectrum and TG-FTIR result indicated that the deposition of ammonium sulfate species was the main deactivation reason at low temperatures,which still exhibited the reactivity with NO above 200℃ on the catalyst surface.There was a synergistic effect among NH3,H2O and SO2that NH3and H2O both accelerated the catalyst deactivation in the presence of SO2at 175℃.The thermal treatment at 400℃ could regenerate the deactivated catalyst and get SCR activity recovered.The particle and monolith catalysts both kept stable NOxconversion at 225℃ with high concentration of H2O and SO2during the long time tests.
