In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asy...In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.展开更多
To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the...To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.展开更多
BACKGROUND Post-stroke depression(PSD)is associated with hypothalamic-pituitary-adrenal(HPA)axis dysfunction and neurotransmitter deficits.Selective serotonin reuptake inhibitors(SSRIs)are commonly used,but their effi...BACKGROUND Post-stroke depression(PSD)is associated with hypothalamic-pituitary-adrenal(HPA)axis dysfunction and neurotransmitter deficits.Selective serotonin reuptake inhibitors(SSRIs)are commonly used,but their efficacy is limited.This study investigated whether combining SSRIs with traditional Chinese medicine(TCM)Free San could enhance their therapeutic effects.AIM To evaluate the clinical efficacy and safety of combining SSRIs with Free San in treating PSD,and to assess its impact on HPA axis function.METHODS Ninety-two patients with PSD were enrolled and randomly divided into control groups(n=46)and study groups(n=46).The control group received the SSRI paroxetine alone,whereas the study group received paroxetine combined with Free San for 4 weeks.Hamilton Depression Scale and TCM syndrome scores were assessed before and after treatment.Serum serotonin,norepinephrine,cortisol,cor-ticotropin-releasing hormone,and adrenocorticotropic hormone were measured.The treatment responses and adverse reactions were recorded.RESULTS After treatment,the Hamilton Depression Scale and TCM syndrome scores were significantly lower in the study group than in the control group(P<0.05).Serum serotonin and norepinephrine levels were significantly higher in the study group than in the control group,whereas cortisol,corticotropin-releasing hormone,and adrenocorticotropic hormone levels were significantly lower(P<0.05).The total efficacy rates were 84.78%and 65.22%in the study and control groups,respectively(P<0.05).No significant differences in adverse reactions were observed between the two groups(P>0.05).CONCLUSION Combining SSRIs with Free San can enhance therapeutic efficacy,improve depressive symptoms,and regulate HPA axis function in patients with PSD with good safety and clinical application value.展开更多
Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via lo...Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.展开更多
The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces...The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.展开更多
Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and pote...Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and potent anti-tumor effect.However,certain limitations such as unstable loading,perfusion stasis,heterogeneous distribution,ectopic distribution,and insufficient dosage,restrict their clinical application.Herein,a novel personalized Y-90 carbon microsphere with high uniformity,high specific activity and high availability(^(90)Y-HUACM)is presented.It is synthesized through planar molecular complex adsorption and chemical deposition solidification.^(90)Y-HUACM exhibited controllable size,excellent biocompatibility,outstanding in vitro and in vivo stability.The radiolabeling efficiency of Y-90 exceeded 99%and the leaching rate of Y-90 is far below 0.1%.Furthermore,the excellent anti-tumor effect,nuclide loading stability,anti-reflux characteristics,precise embolization,and biosafety of^(90)Y-HUACM were validated in a rabbit VX2liver tumor model.In summary,this new,high-performance,and customizable radioactive microsphere provides a superior choice for selective internal radiation treatment of advanced liver cancer is expected to be rapidly applied in clinical practice.展开更多
Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor ...Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor agents a research hotspot.In this study,artificial intelligence(AI)technology and molecular simulation strategies were fully integrated to construct an efficient and precise drug screening pipeline,which combined Voting strategy based on compound-protein interaction(CPI)prediction models,cascade molecular docking,and molecular dynamic(MD)simulations.The biological potential of the screened compounds was further evaluated through enzymatic and cellular activity assays.Among the identified compounds,Cmpd.18 exhibited more potent HDAC6 enzyme inhibitory activity(IC_(50)=5.41 nM)than that of tubastatin A(TubA)(IC_(50)=15.11 nM),along with a favorable subtype selectivity profile(selectivity index z 117.23 for HDAC1),which was further verified by the Western blot analysis.Additionally,Cmpd.18 induced G2/M phase arrest and promoted apoptosis in HCT-116 cells,exerting desirable antiproliferative activity(IC_(50)=2.59 mM).Furthermore,based on long-term MD simulation trajectory,the key residues facilitating Cmpd.18's binding were identified by decomposition free energy analysis,thereby elucidating its binding mechanism.Moreover,the representative conformation analysis also indicated that Cmpd.18 could stably bind to the active pocket in an effective conformation,thus demonstrating the potential for in-depth research of the 2-(2-phenoxyethyl)pyridazin-3(2H)-one scaffold.展开更多
Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N c...Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N catalysis.Monosubstitu-tion C—N bond formation reaction catalyzed by K_(2)CO_(3) also gave novel enol-based target products.This method is simple and mild,with good chemoselectivity,excellent substrate compatibility and tolerance for various functional groups,and achieves gram-scale synthesis.The reaction is a nucleophilic substitution process without the involvement of free radicals.展开更多
The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively red...The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively reduce C=C or C=O bonds while preserving other functional groups within the molecule.This approach serves as a critical strategy for the directional synthesis of high-value molecules.However,achieving such selectivity remains challenging due to the thermodynamic equilibrium and kinetic competition between C=O and C=C bonds inα,β-unsaturated systems.Consequently,constructing precisely targeted catalytic systems is essential to overcome these limitations,offering both fundamental scientific significance and industrial application potential.Metal-organic frameworks(MOFs)and their derivatives have emerged as innovative platforms for designing such systems,owing to their programmable topology,tunable pore microenvironments,spatially controllable active sites,and modifiable electronic structures.This review systematically summarizes the research progress of MOF-based catalysts for selec-tive hydrogenation ofα,β-unsaturated aldehydes/ketones in the last decade,with emphasis on the design strategy,conformational relationship,and catalytic mechanism,aiming to provide new ideas for the design of targeted catalyt-ic systems for the selective hydrogenation ofα,β-unsaturated aldehydes/ketones.展开更多
ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical...ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical properties of the formed alloy was investigated.The microstructure of ZGH401 was analyzed by scanning electron microscope,electron back-scattered diffraction,and electron probe microanalysis.The results show that the defects of the as-built ZGH401 are gradually reduced,the relative density is correspondingly enhanced with increasing the energy density,and the ultimate density can reach 99.6%.An increase in laser power leads to a corresponding rise in hardness of ZGH401,while a faster scanning speed reduces the residual stress in asbuilt ZGH401 samples.In addition,better tensile properties are achieved at room temperature due to more grain boundaries perpendicular to the build direction than parallel to the build direction.The precipitated phases are identified as carbides and Laves phases via chemical composition analysis,with fewer carbides observed at the molten pool boundaries than within the molten pools.展开更多
We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of ...We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.展开更多
The efficient recovery of fluorite is paid more and more attention with the increasing application especially in strategic emerging industries.In this study,acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copo...The efficient recovery of fluorite is paid more and more attention with the increasing application especially in strategic emerging industries.In this study,acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer(AAAMPS)was first used as the depressant in fluorite flotation,and its effect on the flotation separation of fluorite and dolomite in sodium oleate(NaOL)system was investigated.The depression mechanism was analyzed by contact angle measurement,zeta potential test,FTIR and XPS analyses.The micro-flotation test results showed that dolomite can be inhibited in fluorite flotation system in the addition of 2 mg/L AA-AMPS and 20 mg/L NaOL at pH 10.The CaF_(2) grade increased from 49.85%in the artificial mixed mineral to 89.60%in the fluorite concentrate.The depression mechanism indicated that AA-AMPS could adsorb strongly on dolomite surface by the chelation with Ca and Mg active sites.Moreover,the further adsorption of NaOL on dolomite surface was prevented by the AA-AMPS adsorption,but that on fluorite surface was little affected,thereby increasing the difference in the hydrophobicity and floatability of the two minerals.展开更多
Bisphenol A(BPA)has threatened ecological safety and human health due to its endocrine disrupting effect and widely diffused in the environment.Peroxymonosulfate(PMS)based on oxidation technology exhibits good potenti...Bisphenol A(BPA)has threatened ecological safety and human health due to its endocrine disrupting effect and widely diffused in the environment.Peroxymonosulfate(PMS)based on oxidation technology exhibits good potential for environmental remediation whereas the highly efficient activator needs to be developed.Herein,the Bi OBr(BOB)was synthesized to efficiently activate PMS to remove 95.6%of BPA within 60 min.The observed rate constant of BPA removal in BOB/PMS system is 0.049 min^(-1),which is 60 and 148 times to that of the BOB and PMS processes separately and 129 times to the compared Bi OCl(BOC)/PMS system,respectively.Comparison experiments and analytic methods demonstrate that BOB with a larger content of oxygen vacancies(Ov)can act as the bridge of electron transfer between Bi^(3+)/Bi^(4+)with PMS to enhance the activation ability for PMS,resulting in the production of abundant reactive oxygen species(O_(2)^(·-)and ^(1)O_(2)).Additionally,the breakdown processes of BPA and the toxicity of its byproducts were uncovered,and the potential for actual water treatment was evaluated to confirm the detoxification,efficiency,stability and practical use of the BOB/PMS system for eliminating BPA.This study may widen the application of traditional semiconductors and develop the cost-effective PMS activation methods for environmental remediation.展开更多
Europe’s shift toward selective protectionism,particularly targeting China,undermines its commitment to free trade,threatens its industrial competitiveness,and ultimately jeopardizes European prosperity.
Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains ...Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains challenging,inhibiting the rational design of excellent FeV-based catalysts.Here,in this work,a series of FeV catalysts with various compositions,including FeVO_(4),isolated VO_(x),low-polymerized V_(n)O_(x),and crystalline V_(2)O_(5) were prepared by controlling the preparation conditions,and were applied to methanol oxidation to formaldehyde reaction.A FeV_(1.1) catalyst,which consisted of FeVO_(4) and low-polymerized V_(n)O_(x) species showed an excellent catalytic performance with a methanol conversion of 92.3%and a formaldehyde selectivity of 90.6%,which was comparable to that of conventional iron-molybdate catalyst.The results of CH_(3)OH-IR,O_(2) pulse and control experiments revealed a crucial synergistic effect between FeVO_(4) and low-polymerized V_(n)O_(x).It enhanced the oxygen supply capacity and suitable binding and adsorption strengths for formaldehyde intermediates,contributing to the high catalytic activity and formaldehyde selectivity.This study not only advances the understanding of FeV structure but also offers valuable guidelines for selective methanol oxidation to formaldehyde.展开更多
The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and ...The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and most membrane materials cannot separate various oil-water mixtures.S erious membrane pollution would cause a decrease in separation flux.We proposed a pre-identified organic hydrogel surface prepared by micro-nano manufacturing technology for selective oil/water separation with ultra-high separating flux.Stimulated by water,the prepared surface is superhydrophilic-underwater superoleophobic,allowing water to pass through,and stimulated by oil,the prepared surface is superoleophilic-underoil superhydrophobic,allowing oil to pass through.Thus,based on the special solvent-responsive property,the prepared surface has a pre-identified function for water and oil,and could achieve the capture of oil droplets in water and water droplets in oil.In addition,the surface maintains an ultra-high separating efficiency and flux of about 99.85%and 17750 L·m^(-2)·h^(-1),and even after continuous cycles without cleaning,it could keep 99.1%and 16000 L·m^(-2)·h^(-1)due to the excellent anti-fouling ability.This study provides new ideas and methods for designing intelligent oil-water separation devices,and further guidance for achieving on-demand oily wastewater treatment.展开更多
As the density of wireless networks increases globally, the vulnerability of overlapped dense wireless communications to interference by hidden nodes and denial-of-service (DoS) attacks is becoming more apparent. Ther...As the density of wireless networks increases globally, the vulnerability of overlapped dense wireless communications to interference by hidden nodes and denial-of-service (DoS) attacks is becoming more apparent. There exists a gap in research on the detection and response to attacks on Medium Access Control (MAC) mechanisms themselves, which would lead to service outages between nodes. Classifying exploitation and deceptive jamming attacks on control mechanisms is particularly challengingdue to their resemblance to normal heavy communication patterns. Accordingly, this paper proposes a machine learning-based selective attack mitigation model that detects DoS attacks on wireless networks by monitoring packet log data. Based on the type of detected attack, it implements effective corresponding mitigation techniques to restore performance to nodes whose availability has been compromised. Experimental results reveal that the accuracy of the proposed model is 14% higher than that of a baseline anomaly detection model. Further, the appropriate mitigation techniques selected by the proposed system based on the attack type improve the average throughput by more than 440% compared to the case without a response.展开更多
The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of ...The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.展开更多
The aqueous-phase hydrogenation of furfural to furfuryl alcohol using non-noble metal catalysts is constrained by the low activity of catalysts,necessitating high temperatures and high hydrogen pressures,and posing ch...The aqueous-phase hydrogenation of furfural to furfuryl alcohol using non-noble metal catalysts is constrained by the low activity of catalysts,necessitating high temperatures and high hydrogen pressures,and posing challenges in controlling furfuryl alcohol selectivity.Herein,a Co nanoparticle catalyst supported on nitrogendoped carbon derived from MOFs is reported,which adopts a synergistic strategy to enhance catalytic perfor-mance.The nitrogen doping simultaneously promotes hydrogen spillover on the catalyst surface and reduces surface acidity,thereby suppressing acid-catalyzed side reactions.This dual function enables the selective hy-drogenation of-C=O groups to-CH_(2)OH groups in water under mild conditions.Furfural reached 98%con-version with 95%selectivity of furfuryl alcohol at 135℃ and under hydrogen pressure close to atmospheric(0.4 MPa)in 2 h.This study allows a low energy-consuming method for producing furfuryl alcohol from hemicellulose-derived furfural,and provides a promising strategy for the conversion of renewable biomassderived compounds into high value-added chemicals.展开更多
Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction m...Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).展开更多
基金Supported by the National Natural Science Foundation of China(12261018)Universities Key Laboratory of Mathematical Modeling and Data Mining in Guizhou Province(2023013)。
文摘In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.
基金National Natural Science Foundation of China(51504138,51674118,52271177)Hunan Provincial Natural Science Foundation of China(2023JJ50181)Supported by State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(P2024-022)。
文摘To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure.
基金Supported by Open Project of Jiangsu Province Key Laboratory of Integrated Traditional Chinese and Western Medicine for the Prevention and Treatment of Geriatric Diseases,No.202232.
文摘BACKGROUND Post-stroke depression(PSD)is associated with hypothalamic-pituitary-adrenal(HPA)axis dysfunction and neurotransmitter deficits.Selective serotonin reuptake inhibitors(SSRIs)are commonly used,but their efficacy is limited.This study investigated whether combining SSRIs with traditional Chinese medicine(TCM)Free San could enhance their therapeutic effects.AIM To evaluate the clinical efficacy and safety of combining SSRIs with Free San in treating PSD,and to assess its impact on HPA axis function.METHODS Ninety-two patients with PSD were enrolled and randomly divided into control groups(n=46)and study groups(n=46).The control group received the SSRI paroxetine alone,whereas the study group received paroxetine combined with Free San for 4 weeks.Hamilton Depression Scale and TCM syndrome scores were assessed before and after treatment.Serum serotonin,norepinephrine,cortisol,cor-ticotropin-releasing hormone,and adrenocorticotropic hormone were measured.The treatment responses and adverse reactions were recorded.RESULTS After treatment,the Hamilton Depression Scale and TCM syndrome scores were significantly lower in the study group than in the control group(P<0.05).Serum serotonin and norepinephrine levels were significantly higher in the study group than in the control group,whereas cortisol,corticotropin-releasing hormone,and adrenocorticotropic hormone levels were significantly lower(P<0.05).The total efficacy rates were 84.78%and 65.22%in the study and control groups,respectively(P<0.05).No significant differences in adverse reactions were observed between the two groups(P>0.05).CONCLUSION Combining SSRIs with Free San can enhance therapeutic efficacy,improve depressive symptoms,and regulate HPA axis function in patients with PSD with good safety and clinical application value.
基金the National Nature Science Foundation of China for Excellent Young Scientists Fund(32222058)Fundamental Research Foundation of CAF(CAFYBB2022QB001).
文摘Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.
基金supported by the National Key Research and Development Program of China(No.2019YFC1803501)the National Natural Science Foundation of China(No.52074357)+2 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ30713)the Vanadium Titanium Union Foundationthe Project of Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources,Ministry of Natural Resources,China。
文摘The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.
基金supported by the National Major Scientific and Technological Special Project for“Significant New Drugs Development”(No.2018ZX09201018–028)the nuclear energy development projects of China during the 13thFive Year Plan periodthe key research and development project of the Sichuan Provincial Department of Science and Technology(No.18ZDYF1466)。
文摘Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and potent anti-tumor effect.However,certain limitations such as unstable loading,perfusion stasis,heterogeneous distribution,ectopic distribution,and insufficient dosage,restrict their clinical application.Herein,a novel personalized Y-90 carbon microsphere with high uniformity,high specific activity and high availability(^(90)Y-HUACM)is presented.It is synthesized through planar molecular complex adsorption and chemical deposition solidification.^(90)Y-HUACM exhibited controllable size,excellent biocompatibility,outstanding in vitro and in vivo stability.The radiolabeling efficiency of Y-90 exceeded 99%and the leaching rate of Y-90 is far below 0.1%.Furthermore,the excellent anti-tumor effect,nuclide loading stability,anti-reflux characteristics,precise embolization,and biosafety of^(90)Y-HUACM were validated in a rabbit VX2liver tumor model.In summary,this new,high-performance,and customizable radioactive microsphere provides a superior choice for selective internal radiation treatment of advanced liver cancer is expected to be rapidly applied in clinical practice.
基金funded by Central Guidance on Local Science and Technology Development Fund of Hebei Province,China(Grant No.:226Z2605G)the Key Project from Hebei Provincial Department of Science and Technology,China(Grant No.:21372601D)+6 种基金Graduate Student Innovation Grant Program of Hebei Medical University,China(Grant No.:XCXZZB202303)Science Research Project of Hebei Education Department,China(Grant Nos.:BJ2025046,and CYZD202501)Program for Young Scientists in the Field of Natural Science of Hebei Medical University,China(Program Nos.:CYCZ2023010,CYCZ2023011,CYQD2021011,CYQD2021015 and CYQD2023012)Traditional Chinese Medicine Administration Project of Hebei Province,China(Project No.:2025427)National Natural Science Foundation of China(Grant No.:32100771)the Hebei Provincial Medical Science Research Project Plan,China(Project Nos.:20240241 and 20220200)Shijiazhuang Science and Technology Bureau,China(Grant Nos.:241200487A,and 07202204).
文摘Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor agents a research hotspot.In this study,artificial intelligence(AI)technology and molecular simulation strategies were fully integrated to construct an efficient and precise drug screening pipeline,which combined Voting strategy based on compound-protein interaction(CPI)prediction models,cascade molecular docking,and molecular dynamic(MD)simulations.The biological potential of the screened compounds was further evaluated through enzymatic and cellular activity assays.Among the identified compounds,Cmpd.18 exhibited more potent HDAC6 enzyme inhibitory activity(IC_(50)=5.41 nM)than that of tubastatin A(TubA)(IC_(50)=15.11 nM),along with a favorable subtype selectivity profile(selectivity index z 117.23 for HDAC1),which was further verified by the Western blot analysis.Additionally,Cmpd.18 induced G2/M phase arrest and promoted apoptosis in HCT-116 cells,exerting desirable antiproliferative activity(IC_(50)=2.59 mM).Furthermore,based on long-term MD simulation trajectory,the key residues facilitating Cmpd.18's binding were identified by decomposition free energy analysis,thereby elucidating its binding mechanism.Moreover,the representative conformation analysis also indicated that Cmpd.18 could stably bind to the active pocket in an effective conformation,thus demonstrating the potential for in-depth research of the 2-(2-phenoxyethyl)pyridazin-3(2H)-one scaffold.
文摘Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N catalysis.Monosubstitu-tion C—N bond formation reaction catalyzed by K_(2)CO_(3) also gave novel enol-based target products.This method is simple and mild,with good chemoselectivity,excellent substrate compatibility and tolerance for various functional groups,and achieves gram-scale synthesis.The reaction is a nucleophilic substitution process without the involvement of free radicals.
文摘The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively reduce C=C or C=O bonds while preserving other functional groups within the molecule.This approach serves as a critical strategy for the directional synthesis of high-value molecules.However,achieving such selectivity remains challenging due to the thermodynamic equilibrium and kinetic competition between C=O and C=C bonds inα,β-unsaturated systems.Consequently,constructing precisely targeted catalytic systems is essential to overcome these limitations,offering both fundamental scientific significance and industrial application potential.Metal-organic frameworks(MOFs)and their derivatives have emerged as innovative platforms for designing such systems,owing to their programmable topology,tunable pore microenvironments,spatially controllable active sites,and modifiable electronic structures.This review systematically summarizes the research progress of MOF-based catalysts for selec-tive hydrogenation ofα,β-unsaturated aldehydes/ketones in the last decade,with emphasis on the design strategy,conformational relationship,and catalytic mechanism,aiming to provide new ideas for the design of targeted catalyt-ic systems for the selective hydrogenation ofα,β-unsaturated aldehydes/ketones.
基金National Defense Science and Technology Project Management Center(2021-JCJQ-JJ-0092)。
文摘ZGH401 alloy was prepared under varying laser power levels and scanning speeds by the orthogonal test method using selective laser melting(SLM).The effect of different energy densities on microstructure and mechanical properties of the formed alloy was investigated.The microstructure of ZGH401 was analyzed by scanning electron microscope,electron back-scattered diffraction,and electron probe microanalysis.The results show that the defects of the as-built ZGH401 are gradually reduced,the relative density is correspondingly enhanced with increasing the energy density,and the ultimate density can reach 99.6%.An increase in laser power leads to a corresponding rise in hardness of ZGH401,while a faster scanning speed reduces the residual stress in asbuilt ZGH401 samples.In addition,better tensile properties are achieved at room temperature due to more grain boundaries perpendicular to the build direction than parallel to the build direction.The precipitated phases are identified as carbides and Laves phases via chemical composition analysis,with fewer carbides observed at the molten pool boundaries than within the molten pools.
文摘We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.
基金Project(52004333)supported by the National Science Foundation of ChinaProject(2021CB1002)supported by Hunan International Joint Research Center for Efficient and Clean Utilization of Critical Metal Mineral Resources,China。
文摘The efficient recovery of fluorite is paid more and more attention with the increasing application especially in strategic emerging industries.In this study,acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer(AAAMPS)was first used as the depressant in fluorite flotation,and its effect on the flotation separation of fluorite and dolomite in sodium oleate(NaOL)system was investigated.The depression mechanism was analyzed by contact angle measurement,zeta potential test,FTIR and XPS analyses.The micro-flotation test results showed that dolomite can be inhibited in fluorite flotation system in the addition of 2 mg/L AA-AMPS and 20 mg/L NaOL at pH 10.The CaF_(2) grade increased from 49.85%in the artificial mixed mineral to 89.60%in the fluorite concentrate.The depression mechanism indicated that AA-AMPS could adsorb strongly on dolomite surface by the chelation with Ca and Mg active sites.Moreover,the further adsorption of NaOL on dolomite surface was prevented by the AA-AMPS adsorption,but that on fluorite surface was little affected,thereby increasing the difference in the hydrophobicity and floatability of the two minerals.
基金financially supported by the National Key Research and Development Program of China(No.2022YFC3703103)National Natural Science Foundation of China(Nos.22206053,42277427)the Guangzhou Science and Technology Plan Project(No.2024A04J4058)。
文摘Bisphenol A(BPA)has threatened ecological safety and human health due to its endocrine disrupting effect and widely diffused in the environment.Peroxymonosulfate(PMS)based on oxidation technology exhibits good potential for environmental remediation whereas the highly efficient activator needs to be developed.Herein,the Bi OBr(BOB)was synthesized to efficiently activate PMS to remove 95.6%of BPA within 60 min.The observed rate constant of BPA removal in BOB/PMS system is 0.049 min^(-1),which is 60 and 148 times to that of the BOB and PMS processes separately and 129 times to the compared Bi OCl(BOC)/PMS system,respectively.Comparison experiments and analytic methods demonstrate that BOB with a larger content of oxygen vacancies(Ov)can act as the bridge of electron transfer between Bi^(3+)/Bi^(4+)with PMS to enhance the activation ability for PMS,resulting in the production of abundant reactive oxygen species(O_(2)^(·-)and ^(1)O_(2)).Additionally,the breakdown processes of BPA and the toxicity of its byproducts were uncovered,and the potential for actual water treatment was evaluated to confirm the detoxification,efficiency,stability and practical use of the BOB/PMS system for eliminating BPA.This study may widen the application of traditional semiconductors and develop the cost-effective PMS activation methods for environmental remediation.
文摘Europe’s shift toward selective protectionism,particularly targeting China,undermines its commitment to free trade,threatens its industrial competitiveness,and ultimately jeopardizes European prosperity.
文摘Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains challenging,inhibiting the rational design of excellent FeV-based catalysts.Here,in this work,a series of FeV catalysts with various compositions,including FeVO_(4),isolated VO_(x),low-polymerized V_(n)O_(x),and crystalline V_(2)O_(5) were prepared by controlling the preparation conditions,and were applied to methanol oxidation to formaldehyde reaction.A FeV_(1.1) catalyst,which consisted of FeVO_(4) and low-polymerized V_(n)O_(x) species showed an excellent catalytic performance with a methanol conversion of 92.3%and a formaldehyde selectivity of 90.6%,which was comparable to that of conventional iron-molybdate catalyst.The results of CH_(3)OH-IR,O_(2) pulse and control experiments revealed a crucial synergistic effect between FeVO_(4) and low-polymerized V_(n)O_(x).It enhanced the oxygen supply capacity and suitable binding and adsorption strengths for formaldehyde intermediates,contributing to the high catalytic activity and formaldehyde selectivity.This study not only advances the understanding of FeV structure but also offers valuable guidelines for selective methanol oxidation to formaldehyde.
基金the National Natural Science Foundation of China(Nos.52475301,52005222,and 12272151)Open Fund for Key Laboratory of Bionic Engineering(Ministry of Education)of Jilin University(K202207)。
文摘The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and most membrane materials cannot separate various oil-water mixtures.S erious membrane pollution would cause a decrease in separation flux.We proposed a pre-identified organic hydrogel surface prepared by micro-nano manufacturing technology for selective oil/water separation with ultra-high separating flux.Stimulated by water,the prepared surface is superhydrophilic-underwater superoleophobic,allowing water to pass through,and stimulated by oil,the prepared surface is superoleophilic-underoil superhydrophobic,allowing oil to pass through.Thus,based on the special solvent-responsive property,the prepared surface has a pre-identified function for water and oil,and could achieve the capture of oil droplets in water and water droplets in oil.In addition,the surface maintains an ultra-high separating efficiency and flux of about 99.85%and 17750 L·m^(-2)·h^(-1),and even after continuous cycles without cleaning,it could keep 99.1%and 16000 L·m^(-2)·h^(-1)due to the excellent anti-fouling ability.This study provides new ideas and methods for designing intelligent oil-water separation devices,and further guidance for achieving on-demand oily wastewater treatment.
基金supported by the Ministry of Trade,Industry and Energy(MOTIE)under Training Industrial Security Specialist for High-Tech Industry(RS-2024-00415520)supervised by the Korea Institute for Advancement of Technology(KIAT)the Ministry of Science and ICT(MSIT)under the ICT Challenge and Advanced Network of HRD(ICAN)Program(No.IITP-2022-RS-2022-00156310)supervised by the Institute of Information&Communication Technology Planning&Evaluation(IITP).
文摘As the density of wireless networks increases globally, the vulnerability of overlapped dense wireless communications to interference by hidden nodes and denial-of-service (DoS) attacks is becoming more apparent. There exists a gap in research on the detection and response to attacks on Medium Access Control (MAC) mechanisms themselves, which would lead to service outages between nodes. Classifying exploitation and deceptive jamming attacks on control mechanisms is particularly challengingdue to their resemblance to normal heavy communication patterns. Accordingly, this paper proposes a machine learning-based selective attack mitigation model that detects DoS attacks on wireless networks by monitoring packet log data. Based on the type of detected attack, it implements effective corresponding mitigation techniques to restore performance to nodes whose availability has been compromised. Experimental results reveal that the accuracy of the proposed model is 14% higher than that of a baseline anomaly detection model. Further, the appropriate mitigation techniques selected by the proposed system based on the attack type improve the average throughput by more than 440% compared to the case without a response.
基金supported by the National Natural Science Foundation of China(U23A2088,22025206)the Dalian Innovation Support Plan for High Level Talents(2022RG13)+2 种基金DICP(Grant:DICP I202453,DICP I202234)the Fundamental Research Funds for the Central Universities(20720220008)support of the Liaoning Key Laboratory of Biomass Conversion for Energy and Material。
文摘The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.
基金supported by National Natural Science Foundation of China(22379131,22278049,22278049,and U24A20559)China Postdoctoral Science Foundation(2023M733216)+1 种基金Henan Science and Technology Department(242300421355)the Dalian High-Level Talent Innovation Program(2024RJ017).
文摘The aqueous-phase hydrogenation of furfural to furfuryl alcohol using non-noble metal catalysts is constrained by the low activity of catalysts,necessitating high temperatures and high hydrogen pressures,and posing challenges in controlling furfuryl alcohol selectivity.Herein,a Co nanoparticle catalyst supported on nitrogendoped carbon derived from MOFs is reported,which adopts a synergistic strategy to enhance catalytic perfor-mance.The nitrogen doping simultaneously promotes hydrogen spillover on the catalyst surface and reduces surface acidity,thereby suppressing acid-catalyzed side reactions.This dual function enables the selective hy-drogenation of-C=O groups to-CH_(2)OH groups in water under mild conditions.Furfural reached 98%con-version with 95%selectivity of furfuryl alcohol at 135℃ and under hydrogen pressure close to atmospheric(0.4 MPa)in 2 h.This study allows a low energy-consuming method for producing furfuryl alcohol from hemicellulose-derived furfural,and provides a promising strategy for the conversion of renewable biomassderived compounds into high value-added chemicals.
基金Project supported by the National Natural Science Foundation of China(52261037,52401251)Key Research Project of Jiangxi Province(20203ABC28W006)+2 种基金the Research Fund of Key Laboratory of Rare Earths,Chinese Academy of SciencesKey Laboratory of Ionic Rare Earth Re sources and Environment,Ministry of Natural Resources of the People's Republic of China(2022IRERE302)the Ganzhou Science and Technology Innovation Empowerment Youth"Jie bang Gua shuai"Project。
文摘Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).
