Objective: To evaluate the application effect of ultrasound-guided central venous catheterization in the teaching of anesthesia residents. Methods: Forty anesthesia resident companions who received standardized reside...Objective: To evaluate the application effect of ultrasound-guided central venous catheterization in the teaching of anesthesia residents. Methods: Forty anesthesia resident companions who received standardized residency training in our department from July 2018 to July 2020 were randomly divided into an ultrasound group and a control group, with 20 participants in each group. The ultrasound group was taught by ultrasound-guided central venipuncture, while the control group was taught by traditional anatomy. After ten training punctures, all trainees were assessed twice. Results: Both groups could master the technique of central venipuncture. The success rate of first puncture and the overall success rate of puncture in the ultrasound group were significantly higher than those in the control group (p p < 0.05). Conclusion: Compared with the traditional anatomical localization teaching, the use of ultrasound-guided technology can improve the success rate of puncture, save puncture time, reduce related complications, and have a better training effect.展开更多
Interstitial oxygen(O)contamination remains a substantial challenge for metal injection molding(MIM)of titanium alloys.Herein,this critical problem is successfully addressed by regulating the thermal debinding tempera...Interstitial oxygen(O)contamination remains a substantial challenge for metal injection molding(MIM)of titanium alloys.Herein,this critical problem is successfully addressed by regulating the thermal debinding temperature and incorporating the oxygen scavenger LaB_(6).Results indicate that the surface oxide layer(with a thickness of(13.4±0.5)nm)of Ti_(6)Al4V powder begins to dissolve into the Ti matrix within the temperature range of 663–775℃.O contamination in MIM Ti alloys can be effectively mitigated by lowering the thermal debinding temperature and adding LaB6powder.As a result of reduced dissolved O content,the slips of mixedanddislocations are effectively accelerated,leading to improved ductility.Moreover,grain refinement,along with the in situ formation of Ti B whiskers and second-phase La_(2)O_(3)particles,enhances the strength of the material.The fabricated MIM Ti6Al4V sample exhibits excellent mechanical properties,achieving an ultimate tensile strength of(967±5)MPa,a yield strength of(866±8)MPa,and an elongation of 21.4%±0.7%.These tensile properties represent some of the best results reported in the literature for MIM Ti_(6)Al4V alloys.This study offers valuable insights into the development of high-performance MIM Ti alloys and other metal materials.展开更多
Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution an...Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.展开更多
In this paper,a novel SrEr_(2)O_(4)ceramic with relative densities exceeding 96% was synthesized by a conve ntional solid-state reaction method.Furthermo re,investigations of the correlations between its crystal struc...In this paper,a novel SrEr_(2)O_(4)ceramic with relative densities exceeding 96% was synthesized by a conve ntional solid-state reaction method.Furthermo re,investigations of the correlations between its crystal structure,microstructure,and microwave dielectric properties were carried out.Rietveld refinements show that the SrEr_(2)O_(4)ceramics crystallize in the orthorhombic with the space group Pnam.The SrEr_(2)O_(4)ceramic sintered at 1575℃ exhibits the good performance of permittivity(ε_(r))=14.44,quality factor(Q × f)=23271 GHz,and resonant temperature frequency coefficient(τ_(f))=-21.5 ppm/℃,which is attributed to its high lattice energy,packing fraction,and relative density.In addition,to satisfy the requirement of temperature stability for communication devices,near-zero τ_(f) value is obtained by adding CaTiO_(3) at the cost of a small quality factor loss.The SrEr_(2)O_(4)+1.25 wt% CaTiO_(3) composite exhibits decent properties with ε_(r)=18.57,Q×f=19940 GHz,and T_(f)=+3.99 ppm/℃,making it an ideal candidate for microwave band applications.展开更多
Sjögren’s syndrome(SS)is a challenging condition within the realm of rheumatologic immune disorders.Recent studies have indicated that the imbalance in the immune microenvironment,exacerbated by mitochondrial dy...Sjögren’s syndrome(SS)is a challenging condition within the realm of rheumatologic immune disorders.Recent studies have indicated that the imbalance in the immune microenvironment,exacerbated by mitochondrial dysfunction(MDF),plays a critical role in the pathogenesis of SS.The efficacy of traditional Chinese medicine(TCM)in treating SS has been noteworthy.In the present study,we compiled medical cases of SS treated by Lu Zhizheng,a renowned master of Chinese medicine,and identified bidentate achyranthes and American ginseng as high-frequency medicinal pairs utilized in the treatment of desiccation syndrome through data mining.Network pharmacology analysis revealed that key genes associated with these medicinal pairs were linked to both upstream and downstream components of the cGAS-STING signaling pathway.Our findings suggested that bidentate achyranthes and American ginseng might correct MDF through the mtDNA-cGAS-STING signaling axis,thereby restoring the balance of the immune microenvironment in the submandibular gland.This mechanism potentially led to the treatment and alleviation of symptoms associated with SS.展开更多
Groundwater contamination near landfills is commonly caused by leachate leakage,and permeable reactive barriers(PRBs)are widely used for groundwater remediation.However,the deactivation and blockage of the reactive me...Groundwater contamination near landfills is commonly caused by leachate leakage,and permeable reactive barriers(PRBs)are widely used for groundwater remediation.However,the deactivation and blockage of the reactive medium in PRBs limit their long-term effectiveness.In the current study,a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated groundwater.CO_(2)coupled with oxidants was applied for the dispersion and regeneration of the fillers;by injecting CO_(2)to disperse the fillers,the permeability of the PRB was increased and the oxidants could flow evenly into the PRB.The results indicate that the optimumfiller proportion was zero-valent iron(ZVI)/zeolites/activated carbon(AC)=3:8:10 and the optimum oxidant proportion was COD/Na_(2)S_(2)O_(8)/H_(2)O_(2)/Fe^(2+)=1:5:6:5;the oxidation system of Fe^(2+)/H_(2)O_(2)/S_(2)O_(8)^(2−)has a high oxidation efficiency and persistence.The average regeneration rate of zeolites was 72.71%,and the average regeneration rate of AC was 68.40%;the permeability of PRB also increased.This technology is effective for the remediation of landfills in China that have large contaminated areas,an uneven pollutant concentration distribution,and a long pollution duration.The purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater,where pollution sources are difficult to cut off.展开更多
Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modula...Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data.展开更多
The nuisance from odor caused by municipal solid waste(MSW) is resulting in a growing number of public complaints and concerns. Odor pollution occurs in the initial decomposition stage of MSW, including waste collecti...The nuisance from odor caused by municipal solid waste(MSW) is resulting in a growing number of public complaints and concerns. Odor pollution occurs in the initial decomposition stage of MSW, including waste collection, transportation and early pre-treatment. Furthermore, decomposition takes place in waste facilities that are often close to living areas, which can result in odor impacts on local inhabitants. However, this aspect of odor impact from MSW has not been well studied. In the current study, lab-scale waste cells were designed to simulate MSW storage conditions in the early stage. The characteristics of VOCs emissions with different waste compositions were analyzed. The odor concentration( CO, non-dimensional) method and odor intensity were used for the assessment of odor. Ethanol was the substance with highest emission rate. The release rate of VOCs increased with the growth easily biodegradable waste(EBW). VOCs emissions was reduced by 25% when the proportion of EBW decreased from 60% to 45%. Methyl sulfide, ethanol, dimethyl disulfide and ethyl acetate were identified as typical odorants. The EBW proportion in waste is the main factor significantly influencing odor pollution. The CO was 244.51 for the 60% EBW condition, which was only 61.46 for 15% EBW condition. These study results provide important information for the implementation of a garbage sorting policy and the monitoring of odor pollution from waste management.展开更多
Powder hot isostatic pressing(HIP) is an effective method to achieve near-net-shape manufacturing of high-quality complex thinwalled titanium alloy parts, and it has received extensive attention in recent years. Howev...Powder hot isostatic pressing(HIP) is an effective method to achieve near-net-shape manufacturing of high-quality complex thinwalled titanium alloy parts, and it has received extensive attention in recent years. However, there are few reports about the microstructure characteristics on the strengthening and toughening mechanisms of powder hot isostatic pressed(HIPed) titanium alloys. Therefore, TA15powder was prepared into alloy by HIP approach, which was used to explore the microstructure characteristics at different HIP temperatures and the corresponding tensile properties and fracture toughness. Results show that the fabricated alloy has a “basket-like structure” when the HIP temperature is below 950℃, consisting of lath clusters and surrounding small equiaxed grains belts. When the HIP temperature is higher than 950℃, the microstructure gradually transforms into the Widmanstatten structure, accompanied by a significant increase in grain size. The tensile strength and elongation are reduced from 948 MPa and 17.3% for the 910℃ specimen to 861 MPa and 10% for the 970℃ specimen.The corresponding tensile fracture mode changes from transcrystalline plastic fracture to mixed fracture including intercrystalline cleavage.The fracture toughness of the specimens increases from 82.64 MPa·m^(1/2)for the 910℃ specimen to 140.18 MPa·m^(1/2)for the 970℃ specimen.Specimens below 950℃ tend to form holes due to the prior particle boundaries(PPBs), which is not conducive to toughening. Specimens above 950℃ have high fracture toughness due to the crack deflection, crack branching, and shear plastic deformation of the Widmanstatten structure. This study provides a valid reference for the development of powder HIPed titanium alloy.展开更多
A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full constraints.The fuzzy logic system is used to design the approximator,which deals with...A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full constraints.The fuzzy logic system is used to design the approximator,which deals with uncertain and continuous functions in the process of backstepping design.The use of an integral barrier Lyapunov function not only ensures that all states are within the bounds of the constraint,but also mixes the states and errors to directly constrain the state,reducing the conservativeness of the constraint satisfaction condition.Considering that the states in most nonlinear systems are immeasurable,a fuzzy adaptive states observer is constructed to estimate the unknown states.Combined with adaptive backstepping technique,an adaptive fuzzy output feedback control method is proposed.The proposed control method ensures that all signals in the closed-loop system are bounded,and that the tracking error converges to a bounded tight set without violating the full state constraint.The simulation results prove the effectiveness of the proposed control scheme.展开更多
In this paper,CuO_(x)@Ag/CeO_(2) catalysts were synthesized by simple wet-chemical method and equal volume impregnation method.The obtained catalysts were subjected to soot temperature programmed oxidation(soot-TPO)ac...In this paper,CuO_(x)@Ag/CeO_(2) catalysts were synthesized by simple wet-chemical method and equal volume impregnation method.The obtained catalysts were subjected to soot temperature programmed oxidation(soot-TPO)activity tests and were further characterized by various techniques such as X-ray diffraction(XRD),transmission electron microscopy/high-resolution transmission electron microscopy(TEM/HR-TEM),N_(2) physisorption,X-ray photoelectron spectroscopy(XPS)and H_(2)-temperature programmed reduction(H_(2)-TPR).The results show that CuO_(x)@Ag/CeO_(2) synthesized presents well controlled core-shell structures,with nano-cube like Cu_(2)O as the core and Ag decorated polycrystalline CeO_(2) grafting layers as the shell.Such core-shell structured CuO_(x)@Ag/CeO_(2) can successfully construct a secondary oxygen delivery channel(CuO_(x)→CeO_(2)→Ag)to effectively transfer bulk oxygen of the catalyst to the soot,resulting in its excellent soot oxidation activity compared to CuO_(x)@CeO_(2).The potential benefiting effect by Ag introduction over Cu@Ag/Ce can be concluded as:(ⅰ)pumping lattice oxygen and accelerating gaseous O_(2) dissociation to generate significantly increased active surface oxygen content;(ⅱ)modulating a moderate surface oxygen vacancies concentration to maintain more highly active O_(2) species.展开更多
The challenge of producing a high-ductility titanium(Ti)material using inexpensive high-oxygen hydride-dehydride(HDH)Ti powder is hereby addressed by the incorporation of CaB_(6)oxygen-scavenger.The oxygen-scavenging ...The challenge of producing a high-ductility titanium(Ti)material using inexpensive high-oxygen hydride-dehydride(HDH)Ti powder is hereby addressed by the incorporation of CaB_(6)oxygen-scavenger.The oxygen-scavenging behavior,microstructure evolution,mechanical behavior and improvement mechanism were systematically investigated.A continuous TiO_(2)oxide layer with a thickness of approximately 9.3 nm is presented on the HDH Ti powder surface.The oxide layer will dissolve into Ti matrix during sintering,making the increase of c/a value and leading to the Ti-Ti bonds developing from plastic metal bonds to-ward brittle covalent bonds.The CaB_(6)addition can scavenge O impurity and make a significant increase in tensile ductility forα-Ti matrix.A small addition of 0.2 wt.%CaB_(6)provides a superior tensile elongation of 22.2%for Ti material,almost three times as high as that of pure Ti(7.5%).The increase of defor-mation twining activity and grain refinement are responsible for the improved ductility.Furthermore,the CaB_(6)oxygen-scavenger can react with the surface oxide layer to in-situ form rod-like TiB and granular CaTiO_(3)reinforcements,refining the coarse near equiaxed grain ofα-Ti matrix into fine equiaxed crys-tals.The multiple mechanisms of grain-boundary strengthening,load-bearing strengthening of TiB and Orowan strengthening of CaTiO_(3)nanoparticles work together to increase the tensile strength of Ti/CaB_(6)composites.This work offers an effective method to fabricate high-performance Ti material using inex-pensive high-oxygen HDH Ti powder.展开更多
Series of Cu-USY zeolite catalyst with different Cu loading content were synthesized through simple impregnation method.The obtained catalysts were subjected to selective catalytic reduction of NOxwith NH_(3)(NH_(3)-S...Series of Cu-USY zeolite catalyst with different Cu loading content were synthesized through simple impregnation method.The obtained catalysts were subjected to selective catalytic reduction of NOxwith NH_(3)(NH_(3)-SCR) performance evaluation,structural/chemical characterizations such as X-ray diffraction (XRD),N2adsorption/desorption,H_(2)temperature-programmed reduction (H_(2)-TPR),NH_(3)temperature-programmed desorption (NH_(3)-TPD) as well as detailed in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments including CO adsorption,NH_(3)adsorption and NO+O_(2)in situ reactions.Results show that Cu-USY with proper Cu loading (in this work 5Cu-USY with5 wt.%Cu) could be promising candidates with highly efficient NH_(3)-SCR catalytic performance,relatively low byproduct formation and excellent hydrothermal stability,although its SO_(2)poisoning tolerability needs alleviation.Further characterizations reveal that such catalytic advantages can be attributed to both active cu species and surface acid centers evolution modulated by Cu loading.On one hand,Cu species in the super cages of zeolites increases with higher Cu content and being more conducive for NH_(3)-SCR reactivity.On the other hand,higher Cu loading leads to depletion of Br?nsted acid centers and simultaneous formation of abundant Lewis acid centers,which facilitates NH_(4)NO_(3)reduction via NH_(3)adsorbed on Lewis acid centers,thus improving SCR reactivity.However,Cu over-introduction leads to formation of surface highly dispersed CuOx,causing unfavorable NH_(3)oxidation and inferior N2selectivity.展开更多
Increasing overburden pressure is a key factor that alters the chemical and physical properties of soils and sediments. However, limited information is presently available on how aquifer compression impacts water qual...Increasing overburden pressure is a key factor that alters the chemical and physical properties of soils and sediments. However, limited information is presently available on how aquifer compression impacts water quality. We introduced a novel compaction device, which is composited of four parts, including pressure simulator reactor system(PSRS), gas-liquid separator(GLS), automatic collector(AC) and composite control system(CCS). We conducted experiments at various pressures to test the functionality and outcomes of the device. In general, this device can be used to examine changes in water chemistry associated with aquifer compression resulting from compaction(overburden pressure) or groundwater overdraft.展开更多
文摘Objective: To evaluate the application effect of ultrasound-guided central venous catheterization in the teaching of anesthesia residents. Methods: Forty anesthesia resident companions who received standardized residency training in our department from July 2018 to July 2020 were randomly divided into an ultrasound group and a control group, with 20 participants in each group. The ultrasound group was taught by ultrasound-guided central venipuncture, while the control group was taught by traditional anatomy. After ten training punctures, all trainees were assessed twice. Results: Both groups could master the technique of central venipuncture. The success rate of first puncture and the overall success rate of puncture in the ultrasound group were significantly higher than those in the control group (p p < 0.05). Conclusion: Compared with the traditional anatomical localization teaching, the use of ultrasound-guided technology can improve the success rate of puncture, save puncture time, reduce related complications, and have a better training effect.
基金financially supported by the National Natural Science Foundation of China(Nos.52274359 and 52304379)Beijing Natural Science Foundation,China(No.L212021)+4 种基金China National Postdoctoral Program for Innovative Talents(No.BX20220034)China Postdoctoral Science Foundation(No.2022M720403)Fundamental Research Funds for the Central Universities,China(Nos.FRFTP-19005C1Z and 00007718)AECC University Research Cooperation Project,China(No.HFZL2021CXY021)State Key Lab of Advanced Metals and Materials,University of Science and Technology Beijing,China(Nos.2021Z-03 and 2022Z-14)。
文摘Interstitial oxygen(O)contamination remains a substantial challenge for metal injection molding(MIM)of titanium alloys.Herein,this critical problem is successfully addressed by regulating the thermal debinding temperature and incorporating the oxygen scavenger LaB_(6).Results indicate that the surface oxide layer(with a thickness of(13.4±0.5)nm)of Ti_(6)Al4V powder begins to dissolve into the Ti matrix within the temperature range of 663–775℃.O contamination in MIM Ti alloys can be effectively mitigated by lowering the thermal debinding temperature and adding LaB6powder.As a result of reduced dissolved O content,the slips of mixedanddislocations are effectively accelerated,leading to improved ductility.Moreover,grain refinement,along with the in situ formation of Ti B whiskers and second-phase La_(2)O_(3)particles,enhances the strength of the material.The fabricated MIM Ti6Al4V sample exhibits excellent mechanical properties,achieving an ultimate tensile strength of(967±5)MPa,a yield strength of(866±8)MPa,and an elongation of 21.4%±0.7%.These tensile properties represent some of the best results reported in the literature for MIM Ti_(6)Al4V alloys.This study offers valuable insights into the development of high-performance MIM Ti alloys and other metal materials.
基金the National Natural Science Foundation of China(52090034,52273064,52221006)the Fundamental Research Funds for the Central Universities(JD2417)is gratefully acknowledged.
文摘Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.
基金Porject supported by National Natural Science Foundation of China (61761015, 11664008)Guangxi Natural Science Foundation(2018GXNSFFA050001, 2024GXNSFDA010060)High-Level Innovation Team and Outstanding Scholar Program of Guangxi Institutes。
文摘In this paper,a novel SrEr_(2)O_(4)ceramic with relative densities exceeding 96% was synthesized by a conve ntional solid-state reaction method.Furthermo re,investigations of the correlations between its crystal structure,microstructure,and microwave dielectric properties were carried out.Rietveld refinements show that the SrEr_(2)O_(4)ceramics crystallize in the orthorhombic with the space group Pnam.The SrEr_(2)O_(4)ceramic sintered at 1575℃ exhibits the good performance of permittivity(ε_(r))=14.44,quality factor(Q × f)=23271 GHz,and resonant temperature frequency coefficient(τ_(f))=-21.5 ppm/℃,which is attributed to its high lattice energy,packing fraction,and relative density.In addition,to satisfy the requirement of temperature stability for communication devices,near-zero τ_(f) value is obtained by adding CaTiO_(3) at the cost of a small quality factor loss.The SrEr_(2)O_(4)+1.25 wt% CaTiO_(3) composite exhibits decent properties with ε_(r)=18.57,Q×f=19940 GHz,and T_(f)=+3.99 ppm/℃,making it an ideal candidate for microwave band applications.
基金Research on the Knowledge Graph System of “Disease Syndrome Formula (Medicine)” for Rheumatology,Science and Technology Innovation Project of the Chinese Academy of Traditional Chinese Medicine (Grant No. C12021A01507)the Basic Research Business Fee of the Institute of Traditional Chinese Medicine Basic Theory,Chinese Academy of Traditional Chinese Medicine,is based on knowledge graphs and deep learning to trace the academic ideas of Lu Zhizheng in the treatment of rheumatism during three periods (Grant No. YZX-202317)+1 种基金Central High-level Chinese Medicine Hospital Clinical Research and Results Translation Capacity Enhancement Program (Grant No. HLCMHPP20230120)High Level Chinese Medical Hospital Promotion Project (Grant No. HLCMHPP2023087)。
文摘Sjögren’s syndrome(SS)is a challenging condition within the realm of rheumatologic immune disorders.Recent studies have indicated that the imbalance in the immune microenvironment,exacerbated by mitochondrial dysfunction(MDF),plays a critical role in the pathogenesis of SS.The efficacy of traditional Chinese medicine(TCM)in treating SS has been noteworthy.In the present study,we compiled medical cases of SS treated by Lu Zhizheng,a renowned master of Chinese medicine,and identified bidentate achyranthes and American ginseng as high-frequency medicinal pairs utilized in the treatment of desiccation syndrome through data mining.Network pharmacology analysis revealed that key genes associated with these medicinal pairs were linked to both upstream and downstream components of the cGAS-STING signaling pathway.Our findings suggested that bidentate achyranthes and American ginseng might correct MDF through the mtDNA-cGAS-STING signaling axis,thereby restoring the balance of the immune microenvironment in the submandibular gland.This mechanism potentially led to the treatment and alleviation of symptoms associated with SS.
文摘Groundwater contamination near landfills is commonly caused by leachate leakage,and permeable reactive barriers(PRBs)are widely used for groundwater remediation.However,the deactivation and blockage of the reactive medium in PRBs limit their long-term effectiveness.In the current study,a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated groundwater.CO_(2)coupled with oxidants was applied for the dispersion and regeneration of the fillers;by injecting CO_(2)to disperse the fillers,the permeability of the PRB was increased and the oxidants could flow evenly into the PRB.The results indicate that the optimumfiller proportion was zero-valent iron(ZVI)/zeolites/activated carbon(AC)=3:8:10 and the optimum oxidant proportion was COD/Na_(2)S_(2)O_(8)/H_(2)O_(2)/Fe^(2+)=1:5:6:5;the oxidation system of Fe^(2+)/H_(2)O_(2)/S_(2)O_(8)^(2−)has a high oxidation efficiency and persistence.The average regeneration rate of zeolites was 72.71%,and the average regeneration rate of AC was 68.40%;the permeability of PRB also increased.This technology is effective for the remediation of landfills in China that have large contaminated areas,an uneven pollutant concentration distribution,and a long pollution duration.The purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater,where pollution sources are difficult to cut off.
基金supported by the National Magnetic Confinement Fusion Program of China(No.2019YFE03090200)by National Natural Science Foundation of China(Nos.11975231,12175277 and 12305249).
文摘Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data.
基金financially supported by the Nation Natural Science Foundation of China (No. 51808520)the State Environmental Protection Key Laboratory of Odor Pollution Control (No. 20200502)。
文摘The nuisance from odor caused by municipal solid waste(MSW) is resulting in a growing number of public complaints and concerns. Odor pollution occurs in the initial decomposition stage of MSW, including waste collection, transportation and early pre-treatment. Furthermore, decomposition takes place in waste facilities that are often close to living areas, which can result in odor impacts on local inhabitants. However, this aspect of odor impact from MSW has not been well studied. In the current study, lab-scale waste cells were designed to simulate MSW storage conditions in the early stage. The characteristics of VOCs emissions with different waste compositions were analyzed. The odor concentration( CO, non-dimensional) method and odor intensity were used for the assessment of odor. Ethanol was the substance with highest emission rate. The release rate of VOCs increased with the growth easily biodegradable waste(EBW). VOCs emissions was reduced by 25% when the proportion of EBW decreased from 60% to 45%. Methyl sulfide, ethanol, dimethyl disulfide and ethyl acetate were identified as typical odorants. The EBW proportion in waste is the main factor significantly influencing odor pollution. The CO was 244.51 for the 60% EBW condition, which was only 61.46 for 15% EBW condition. These study results provide important information for the implementation of a garbage sorting policy and the monitoring of odor pollution from waste management.
基金financially supported by the National Natural Science Foundation of China (Nos. 51874037 and 51922004)the Beijing Natural Science Foundation (No. 2212035)+1 种基金the Fundamental Research Funds for the Central Universities (No. FRF-TP-19005C1Z)the National Defense Basic Research Project (No. JCKY2017213004)。
文摘Powder hot isostatic pressing(HIP) is an effective method to achieve near-net-shape manufacturing of high-quality complex thinwalled titanium alloy parts, and it has received extensive attention in recent years. However, there are few reports about the microstructure characteristics on the strengthening and toughening mechanisms of powder hot isostatic pressed(HIPed) titanium alloys. Therefore, TA15powder was prepared into alloy by HIP approach, which was used to explore the microstructure characteristics at different HIP temperatures and the corresponding tensile properties and fracture toughness. Results show that the fabricated alloy has a “basket-like structure” when the HIP temperature is below 950℃, consisting of lath clusters and surrounding small equiaxed grains belts. When the HIP temperature is higher than 950℃, the microstructure gradually transforms into the Widmanstatten structure, accompanied by a significant increase in grain size. The tensile strength and elongation are reduced from 948 MPa and 17.3% for the 910℃ specimen to 861 MPa and 10% for the 970℃ specimen.The corresponding tensile fracture mode changes from transcrystalline plastic fracture to mixed fracture including intercrystalline cleavage.The fracture toughness of the specimens increases from 82.64 MPa·m^(1/2)for the 910℃ specimen to 140.18 MPa·m^(1/2)for the 970℃ specimen.Specimens below 950℃ tend to form holes due to the prior particle boundaries(PPBs), which is not conducive to toughening. Specimens above 950℃ have high fracture toughness due to the crack deflection, crack branching, and shear plastic deformation of the Widmanstatten structure. This study provides a valid reference for the development of powder HIPed titanium alloy.
基金supported in part by the National Natural Science Foundation of China(6202530361973147)the LiaoNing Revitalization Talents Program(XLYC1907050)。
文摘A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full constraints.The fuzzy logic system is used to design the approximator,which deals with uncertain and continuous functions in the process of backstepping design.The use of an integral barrier Lyapunov function not only ensures that all states are within the bounds of the constraint,but also mixes the states and errors to directly constrain the state,reducing the conservativeness of the constraint satisfaction condition.Considering that the states in most nonlinear systems are immeasurable,a fuzzy adaptive states observer is constructed to estimate the unknown states.Combined with adaptive backstepping technique,an adaptive fuzzy output feedback control method is proposed.The proposed control method ensures that all signals in the closed-loop system are bounded,and that the tracking error converges to a bounded tight set without violating the full state constraint.The simulation results prove the effectiveness of the proposed control scheme.
基金Project supported by National Key R&D Program of China(2017YFC0211102)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJB610005)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20201037)Key Research and Development Program of Anhui Province(202104g01020006)the Scientific Research Fund of Nanjing Institute of Technology(YKJ2019111,YKJ2019110)。
文摘In this paper,CuO_(x)@Ag/CeO_(2) catalysts were synthesized by simple wet-chemical method and equal volume impregnation method.The obtained catalysts were subjected to soot temperature programmed oxidation(soot-TPO)activity tests and were further characterized by various techniques such as X-ray diffraction(XRD),transmission electron microscopy/high-resolution transmission electron microscopy(TEM/HR-TEM),N_(2) physisorption,X-ray photoelectron spectroscopy(XPS)and H_(2)-temperature programmed reduction(H_(2)-TPR).The results show that CuO_(x)@Ag/CeO_(2) synthesized presents well controlled core-shell structures,with nano-cube like Cu_(2)O as the core and Ag decorated polycrystalline CeO_(2) grafting layers as the shell.Such core-shell structured CuO_(x)@Ag/CeO_(2) can successfully construct a secondary oxygen delivery channel(CuO_(x)→CeO_(2)→Ag)to effectively transfer bulk oxygen of the catalyst to the soot,resulting in its excellent soot oxidation activity compared to CuO_(x)@CeO_(2).The potential benefiting effect by Ag introduction over Cu@Ag/Ce can be concluded as:(ⅰ)pumping lattice oxygen and accelerating gaseous O_(2) dissociation to generate significantly increased active surface oxygen content;(ⅱ)modulating a moderate surface oxygen vacancies concentration to maintain more highly active O_(2) species.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51874037 and 51922004)the Beijing Natural Science Foundation(No.2212035)+2 种基金the National Postdoctoral Program for Innovative Talents(No.BX20220034)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-19005C1Z and 00007718)the State Key Lab of Advanced Metals and Materials,University of Science and Technology Beijing(Nos.2021Z-03 and 2022Z-14).
文摘The challenge of producing a high-ductility titanium(Ti)material using inexpensive high-oxygen hydride-dehydride(HDH)Ti powder is hereby addressed by the incorporation of CaB_(6)oxygen-scavenger.The oxygen-scavenging behavior,microstructure evolution,mechanical behavior and improvement mechanism were systematically investigated.A continuous TiO_(2)oxide layer with a thickness of approximately 9.3 nm is presented on the HDH Ti powder surface.The oxide layer will dissolve into Ti matrix during sintering,making the increase of c/a value and leading to the Ti-Ti bonds developing from plastic metal bonds to-ward brittle covalent bonds.The CaB_(6)addition can scavenge O impurity and make a significant increase in tensile ductility forα-Ti matrix.A small addition of 0.2 wt.%CaB_(6)provides a superior tensile elongation of 22.2%for Ti material,almost three times as high as that of pure Ti(7.5%).The increase of defor-mation twining activity and grain refinement are responsible for the improved ductility.Furthermore,the CaB_(6)oxygen-scavenger can react with the surface oxide layer to in-situ form rod-like TiB and granular CaTiO_(3)reinforcements,refining the coarse near equiaxed grain ofα-Ti matrix into fine equiaxed crys-tals.The multiple mechanisms of grain-boundary strengthening,load-bearing strengthening of TiB and Orowan strengthening of CaTiO_(3)nanoparticles work together to increase the tensile strength of Ti/CaB_(6)composites.This work offers an effective method to fabricate high-performance Ti material using inex-pensive high-oxygen HDH Ti powder.
基金supported by the Key Program of Science Technology Department of Zhejiang Province (No.2018C03037)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.20KJB610005)+2 种基金the Natural Science Foundation of Jiangsu Province (Nos.BK20201037,BK20190705)Key Research and Development Program of Anhui Province (No.202104g01020006)the Scientific Research Fund of Nanjing Institute of Technology (Nos.YKJ2019111 and YKJ2019110)。
文摘Series of Cu-USY zeolite catalyst with different Cu loading content were synthesized through simple impregnation method.The obtained catalysts were subjected to selective catalytic reduction of NOxwith NH_(3)(NH_(3)-SCR) performance evaluation,structural/chemical characterizations such as X-ray diffraction (XRD),N2adsorption/desorption,H_(2)temperature-programmed reduction (H_(2)-TPR),NH_(3)temperature-programmed desorption (NH_(3)-TPD) as well as detailed in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments including CO adsorption,NH_(3)adsorption and NO+O_(2)in situ reactions.Results show that Cu-USY with proper Cu loading (in this work 5Cu-USY with5 wt.%Cu) could be promising candidates with highly efficient NH_(3)-SCR catalytic performance,relatively low byproduct formation and excellent hydrothermal stability,although its SO_(2)poisoning tolerability needs alleviation.Further characterizations reveal that such catalytic advantages can be attributed to both active cu species and surface acid centers evolution modulated by Cu loading.On one hand,Cu species in the super cages of zeolites increases with higher Cu content and being more conducive for NH_(3)-SCR reactivity.On the other hand,higher Cu loading leads to depletion of Br?nsted acid centers and simultaneous formation of abundant Lewis acid centers,which facilitates NH_(4)NO_(3)reduction via NH_(3)adsorbed on Lewis acid centers,thus improving SCR reactivity.However,Cu over-introduction leads to formation of surface highly dispersed CuOx,causing unfavorable NH_(3)oxidation and inferior N2selectivity.
基金the National Natural Science Foundation of China(Nos.41630318,41521001)the Wuhan Institute of Industrial Technology of Geological Resources&Environment for their financial supports。
文摘Increasing overburden pressure is a key factor that alters the chemical and physical properties of soils and sediments. However, limited information is presently available on how aquifer compression impacts water quality. We introduced a novel compaction device, which is composited of four parts, including pressure simulator reactor system(PSRS), gas-liquid separator(GLS), automatic collector(AC) and composite control system(CCS). We conducted experiments at various pressures to test the functionality and outcomes of the device. In general, this device can be used to examine changes in water chemistry associated with aquifer compression resulting from compaction(overburden pressure) or groundwater overdraft.
