Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are...Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are usually toxic and may cause water pollution.In this work,Ag NPs(31.2 nm in diameter)were prepared using the extract of straw,an agricultural waste,as the reducing and stabilizing agent.Experimental analysis revealed that the straw extract contained lignin,the structure of which possesses phenolic hydroxyl and methoxy groups that facilitate the reduction of silver salts into Ag NPs.The surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their aggregation.After the prepared Ag NPs were added to the precursor solution of acrylamide,free radical polymerization was triggered without the need for extra heating or light irradiation,resulting in the rapid formation of an Ag NP-polyacrylamide composite hydrogel.The inhibition zone test proved that the composite hydrogel possessed excellent antibacterial ability due to the presence of Ag NPs.The prepared hydrogel may have potential applications in the fabrication of biomedical materials,such as antibacterial dressings.展开更多
The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investiga...The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investigates how quantum confinement governs the charge transport,exciton dynamics,and emission efficiency in QD-LEDs,using CsPbI_(3) QDs as a model system.By systematically varying QD sizes,we reveal size-dependent trade-offs in LED performance,such as enhanced efficiency for smaller QDs but increased brightness and stability for larger QDs under high current densities.Our findings offer critical insights into the design of high-performance QD-LEDs,paving the way for scalable and energy-efficient optoelectronic devices.展开更多
Dear Editor,This letter focuses on the remaining useful life(RUL)prediction task under limited labeled samples.Existing machine-learning-based RUL prediction methods for this task usually pay attention to mining degra...Dear Editor,This letter focuses on the remaining useful life(RUL)prediction task under limited labeled samples.Existing machine-learning-based RUL prediction methods for this task usually pay attention to mining degradation information to improve the prediction accuracy of degradation value or health indicator for the next epoch.However,they ignore the cumulative prediction error caused by iterations before reaching the failure point.展开更多
Green hydrogen production by alkaline water electrolysis is an important technology in the decarbonization of the current industry.However,its large-scale application is limited by mediocre performance of conventional...Green hydrogen production by alkaline water electrolysis is an important technology in the decarbonization of the current industry.However,its large-scale application is limited by mediocre performance of conventional Raney Ni electrocatalysts.Herein,high-performance NiMoZn alloy catalysts of the Raney Ni type are developed by pulse electrodeposition for the hydrogen evolution reaction(HER).The optimized catalyst,NMZ-CA,exhibits an overpotential of 37 mV at 10 mA·cm^(-2) and a Tafel slope of 27 mV·dec^(-1) in 1 mol·L^(-1) KOH.Tafel slope measurements,X-ray photoelectron spectroscopy,and H_(2) temperatureprogrammed desorption experiments show that the incorporation of Mo and Zn in Ni weakens the binding of HER intermediate(H_(ads))on strongly adsorbing sites,leading to improved electrochemical kinetics.Electron microscopy and X-ray diffraction study reveals that a phase-pure Mo-doped Ni2Zn11 intermetallic precatalyst formed via pulse electrodeposition and subsequent heat treatment is key to the structure integrity and performance of the catalyst after activation by alkaline leaching.Modificationof NMZ-CA with PTFE enhances its HER performance by facilitating gas removal and improving structure integrity.A practical alkaline water electrolyzer built on the modifiedNMZ/PTFE-CA electrode delivers 2.0 A·cm^(-2) at 1.92 V cell voltage and operates for 250 h without decay.This work provides insights into the synergy between Ni,Mo,and Zn in Raney Ni-type catalysts,and demonstrates the hydrophobic modification as an effective strategy for electrode development in high-performance alkaline water electrolysis.展开更多
In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(...In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(−)][DBUH^(+)],a series of novel heterogeneous dual-ionic poly(ionic liquid)s(PILs)were synthesized readily from 2-(dimethylamino)ethyl methacrylate(DMAEMA),bromo-substituted aliphatic acids,organic bases and divinylbenzene(DVB).The structures,compositions and morphologies were characterized or determined by nuclear magnetic resonance(NMR),thermal gravimetric analysis(TGA),infrared spectroscopy(IR),scanning electron microscopes(SEM),and Brunauer-Emmett-Teller analysis(BET),etc.Application of the P[D+COO^(−)][Br^(−)][DBUH^(+)]series as catalysts in converting CO_(2)into cyclic carbonates showed that P[D+COO^(−)][Br^(−)][DBUH^(+)]-2/1/0.6was able to catalyze epiclorohydrin-CO_(2)cycloaddition the most efficiently.This afforded chloropropylene carbonate(CPC)in 98.4%yield with≥99%selectivity in 24 hr under solvent-and additive-free conditions at atmospheric pressure.Reusability experiments showed that recycling of the catalyst 6 times only resulted in a slight decline in the catalytic performance.In addition,it could be used for the synthesis of a variety of differently substituted cyclic carbonates in good to excellent yields.Finally,key catalytic active sites were probed,and a reasonable mechanism was proposed accordingly.In summary,this work poses an efficient strategy for heterogenization of dual-ionic PILs and provides amild and environmentally benign approach to the fixation and utilization of carbon dioxide.展开更多
Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase...Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.展开更多
New water-soluble fluorescent tetracationic imidazolium-based macrocycles are synthesized via a modular SN2 nucleophilic substitution reaction.The positive charge and acidic C-H sites of these macrocycles enable them ...New water-soluble fluorescent tetracationic imidazolium-based macrocycles are synthesized via a modular SN2 nucleophilic substitution reaction.The positive charge and acidic C-H sites of these macrocycles enable them to bind with nucleotides in water,driven by hydrogen bonds and electrostatic interactions.The binding is high affinity for suitable nucleotides.These properties position them as promising candidates for the selective sensing of nucleotides.展开更多
Gallium oxide(Ga_(2)O_(3))is a promising material for next-generation power devices due to its ultrawide bandgap and extremely high critical electric field strength;however,the strong anisotropy and cleavage tendency ...Gallium oxide(Ga_(2)O_(3))is a promising material for next-generation power devices due to its ultrawide bandgap and extremely high critical electric field strength;however,the strong anisotropy and cleavage tendency of Ga_(2)O_(3)pose significant challenges for high-precision surface processing.In this work,a systematic study was conducted through tribological analysis of monocrystalline(001)β-Ga_(2)O_(3).Initially,reciprocal sliding tests were conducted onβ-Ga_(2)O_(3)along different crystallographic directions,[100]and[010].The results revealed that the[100]direction was more wear resistant,while the[010]direction was more prone to failure.Indentation experiments on(001)β-Ga_(2)O_(3)showed extensive slip and cleavage cracking along different crystallographic orientations,indicating that mechanical wear might dominate the wear mode of this material.Subsequently,sliding tests under various environmental conditions revealed that the wear rate was correlated with humidity.Additionally,β-Ga_(2)O_(3)exhibited time-dependent frictional behavior,with its coefficient of friction stabilizing around 0.1,0.5,and 0.9 at different stages during the wear test.These findings indicate that the frictional behavior of Ga_(2)O_(3)is closely linked to the state of its surface.This study provides critical insights into the tribological behavior of Ga_(2)O_(3)and offers guidance for ultraprecision machining of this material.展开更多
Despite significant advancements in the power conversion efficiency(PCE)of perovskite/silicon tandem solar cells,improving carrier management in top cells remains challenging due to the defective dual interfaces of wi...Despite significant advancements in the power conversion efficiency(PCE)of perovskite/silicon tandem solar cells,improving carrier management in top cells remains challenging due to the defective dual interfaces of wide-bandgap perovskite,particularly on textured silicon surfaces.Herein,a series of halide ions(Cl^(-),Br^(-),I^(-))substituted piperazinium salts are designed and synthesized as post-treatment modifiers for perovskite surfaces.Notably,piperazinium chloride induces an asymmetric bidirectional ions distribution from the top to the bottom surface,with large piperazinium cations concentrating at the perovskite surface and small chloride anions migrating downward to accumulate at the buried interface.This results in effective dual-interface defect passivation and energy band modulation,enabling wide-bandgap(1.68 eV)perovskite solar cells to achieve a PCE of 22.3%and a record product of open-circuit voltage×fill factor(84.4%relative to the Shockley-Queisser limit).Furthermore,the device retains 91.3%of its initial efficiency after 1200 h of maximum power point tracking without encapsulation.When integrated with double-textured silicon heterojunction solar cells,a remarkable PCE of 31.5%is achieved for a 1.04 cm^(2) monolithic perovskite/silicon tandem solar cell,exhibiting excellent long-term operational stability(T_(80)=755 h)without encapsulation in ambient air.This work provides a convenient strategy on dual-interface engineering for making high-efficiency and stable perovskite platforms.展开更多
Objective:Ulcerative colitis is closely associated with intestinal stem cell(ISC)loss and impaired intestinal mucus barrier.Sinisan(SNS),a compound Chinese herbal medicine,has a long history in the treatment of intest...Objective:Ulcerative colitis is closely associated with intestinal stem cell(ISC)loss and impaired intestinal mucus barrier.Sinisan(SNS),a compound Chinese herbal medicine,has a long history in the treatment of intestinal dysfunction,yet whether SNS can relieve acute experimental colitis by modulating ISC proliferation and secretory cell differentiation has not been studied.Our study tested the effect of SNS against acute colitis and focused on the mechanisms involving intestinal barrier recovery.Methods:Network pharmacology analysis and blood entry component analysis of SNS were used to explore the underlying mechanism by which SNS affects the acute dextran sulfate sodium(DSS)-induced murine colitis model.RNA-sequencing was used to demonstrate the mechanism.Further,reverse transcription-quantitative polymerase chain reaction,immunofluorescence staining,and alcian blue and periodic acid-Schiff staining were performed in vivo and in the colonic organoids to investigate the cell lineage differentiation-related mechanism of SNS.Furthermore,potential active ingredients from SNS were predicted by network pharmacology analysis.Results:SNS dramatically suppressed DSS-induced acute colonic inflammation in mice.RNA-sequencing analysis revealed downregulation of inflammation and apoptosis-related genes,and upregulation of lipid metabolism and proliferation-related genes,such as Irf7,Ppara,Clspn and Hspa5.Additionally,ISC renewal and intestinal secretory cell lineage commitment were significantly promoted by SNS both in vivo and in vitro in colonic organoids,leading to enhanced mucin expression.Furthermore,potential active ingredients from SNS that mediated inflammation,lipid metabolism,proliferation,apoptosis,stem cells and secretory cells were predicted using a network pharmacology approach.Conclusion:Our study shed light on the underlying mechanism of SNS in attenuating acute colitis from the perspective of ISC renewal and secretory lineage cell differentiation,suggesting a of novel therapeutic strategy against colitis.展开更多
AIM:To investigate the biological role of mi R-1290 in esophageal squamous cell carcinoma(ESCC) progression and invasion and the underlying mechanism.METHODS:Quantitative real-time polymerase chain reaction(q RT-PCR) ...AIM:To investigate the biological role of mi R-1290 in esophageal squamous cell carcinoma(ESCC) progression and invasion and the underlying mechanism.METHODS:Quantitative real-time polymerase chain reaction(q RT-PCR) was performed to evaluate mi R-1290 expression in ESCC tissue samples.The roles of mi R-1290 in cell proliferation,migration and invasion were identified using mi R-1290 mimic-transfected cells.In addition,the regulatory effect of mi R-1290 on suppressor of cancer cell invasion(SCAI) was evaluated using q RT-PCR,Western blot analysis and a dual luciferase reporter assay.RESULTS:mi R-1290 was significantly upregulated in ESCC tissue samples compared with normal adjacent tissues(9.213 ± 1.150 vs 1.000 ± 0.0),(P < 0.01).Upregulation of mi R-1290 was associated with tumor differentiation(P = 0.021),N classification(P = 0.006) and tumor-node-metastasis stage(P = 0.021) in ESCC patients.Moreover,ectopic mi R-1290 expression potently promoted ESCC cell growth(P < 0.01),migration(P < 0.01) and invasion(P < 0.01) in vitro.mi R-1290 overexpression in ESCC cell lines decreased SCAI expression at the translational level and reduced SCAI-driven luciferase-reporter activity(P < 0.01).CONCLUSION:Our findings suggested that mi R-1290 may play an oncogenic role in cellular processes of ESCC.展开更多
Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. ...Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. WB-DWI was performed by using short TI inversion recovery echo-planar imaging sequence with free breathing and built-in body coil. Axial T2- weighted imaging images of the same location were used as reference. The results of WB-DWI were compared with pathological results and other imaging modalities. The mean apparent diffusion coefficient （ADC） values of different kinds of lymph nodes were compared. Results WB-DWI was positive in all 18 cases with lymphoma, 5 cases with metastatic lymph nodes and 4 of 8 eases with benign lymphadenopathy. The mean ADC value of lymphomatous, metastatic and benign lymph nodes was （0.87 ± 0.17） × 10^3, （0.98± 0.09） × 10^3 and （1.20 ± 0.10） × 10^3 mm^2/s. There was significant difference in ADC value between benign lymph nodes and other two groups （P 〈 0.01）. The sensitivity, specificity and accuracy of WB-DWI in diagnosis of lymphoma were 100% （18/18）, 30.8% （4/13） and 71.0% （22/31）. When an ADC value of 1.08 × 10^-3 mm^2/s was used as the threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with sensitivity of 87.8% and specificity of 91.3%. Sixteen of eighteen cases （88.9%） of lymphoma were accurately staged in accordance with clinical staging. Conclusions WB-DWI is a sensitive, but less specific technique for diagnosis of lymphoma. It is difficult to differentiate lymphnmatous from metastatic lymph nodes using WB-DWI. However, it is a valuable imaging modality for staging of patients with malignant lymphoma.展开更多
Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cer...Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cervical cancer by cervical biopsy and 24 female patients with other suspected pelvic abnormalities received preoperative body DWI scan. Results of body DWI were compared with pathological findings. The apparent diffusion coefficient (ADC) values of normal cervix and different pathological types of cervical cancer were compared. ADC value of normal or inflammatory lymph nodes was also compared with that of metastatic ones. Student's t test was used for statistical analysis. Results There were 5 adenocarcinomas and 19 epitheliomas showed with biopsy results, and DWI showed 21 cervical lesions out of them (87.5%). ADC values of the normal cervix (n = 24), epithelioma (n = 19), and adenocar- cinoma (n = 5) were (1.73 ± 0.31) ×10-3, (0.88 ± 0.22) ×10-3, and (1.08 ± 0.12) ×10-3 mm2/s, respectively. Statistical analysis showed significant difference in ADC value between normal cervical tissue and either tumor tissues (both P < 0.01). In patients had lymphadenectomy (n = 24), totally 67 lymph nodes including 16 metastatic lymph nodes were pathologically analyzed, and DWI showed 66 (98.5%) out of them. ADC values of normal/inflammatory and metastatic lymph nodes were (1.07 ± 0.16) ×10-3 and (0.77 ± 0.13) ×10-3 mm2/s (P < 0.01). Receiver operating characteristic (ROC) curve of ADC value of metastatic lymph node showed that area under curve was 0.961. Conclusions ADC value in cervical carcinoma is lower than that in normal cervix, and ADC may have predictive value in subtype discrimination. ADC value may improve the preoperative characterization of lymph node metastasis. And at least abdominal and pelvic DWI scan is suggested for N staging evaluation in such patients.展开更多
Coagulation and precipitation is a widely applied method to remove F-from wastewater.In this work,the effect of coagulation on the removal of F-and organic matter from coking wastewater was studied using Al Cl3and Fe ...Coagulation and precipitation is a widely applied method to remove F-from wastewater.In this work,the effect of coagulation on the removal of F-and organic matter from coking wastewater was studied using Al Cl3and Fe Cl3as compound coagulants.The removal rates of F-and organic matter under different coagulant doses and p H conditions were investigated.The results show that the highest removal rates of F-by Al Cl3and Fe Cl3are 94.4%and 25.4%,respectively;when the dosage is 10 mmol/L,the TOC removal rates of Fe Cl3and Al Cl3reach 20.4%and 34.7%,respectively.Therefore,the removal rate of F-by Al Cl3is higher than that of Fe Cl3,but the removal rate of organic matter by Fe Cl3is relatively higher.The addition of Ca2+can promote the removal of F-,but the removal rate of organic matter decreases.In addition,by investigating the effects of different p H and Fe–Al ratio on the removal rate,the removal effect of adding Fe Cl3and Al Cl3at the same time was discussed.The results show that the most suitable working condition for the removal of organic matter and F-is that the p H is 6.5 and the molar ratio of Al/Fe is 8:2.Overall,the removal mechanism of F-and organic matter in coking wastewater by Fe Cl3and Al Cl3was explored in this study.The experimental results can provide reference for the advanced treatment of coking wastewater.展开更多
Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.Thi...Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.This review intends to summarize the timely references and insights for the recent advances in MOFs that are used in AOPs.Starting with the preparation methodologies,including conventional hydrothermal method,electrochemical method,sol-gel method,and emerging microwave and ultrasound assisted synthesis methods.Application and mechanism for MOFs using in various AOPs of Fenton-like,photocatalysis,catalytic ozonation,persulfate catalysis and other emerging oxidation methods are emphatically discussed.We hope this review can comprehensively summarize the research and application progress of MOFs in AOPs,deepen the understanding of the catalytic mechanisms.展开更多
A new acylated flavonoid glycoside, 3-O-kaempferol-3-O-acetyl-6-O-(p-coumaroyl)-- D-glucopyranoside 1 was isolated from the whole plant of Anaphalis aureo-punctata. The structure was established by spectral methods.
Bromination is used as a strategy to improve biological activity in medicinal chemistry.In order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3,2-b]-1,...Bromination is used as a strategy to improve biological activity in medicinal chemistry.In order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one scaffold,based on our previous work and molecular modeling,a series of novel 3-aryl-6-（bromoarylrnethyl）-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were designed by molecular docking,synthesized and characterized by mass spectra,infrared spectra,proton NMR and elemental analyses.The study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive control.Most of all target compounds exhibited more than 45%inhibition at 10μmol/L.The preliminary structureactivity relationship was the bromine atoms and the hydroxyl group at the phenyl ring at the C6 position of the parent nucleus played significant roles in the AChE inhibitory activity of the target compounds.展开更多
This study explored the catalytic mechanism and performance impacted by the materials ratio of Fe_(3)O_(4)-GO_(x) composites in three typical advanced oxidation processes(AOPs)of O_(3),peroxodisulfate(PDS)and photo-Fe...This study explored the catalytic mechanism and performance impacted by the materials ratio of Fe_(3)O_(4)-GO_(x) composites in three typical advanced oxidation processes(AOPs)of O_(3),peroxodisulfate(PDS)and photo-Fenton processes for tetracycline hydrochloride(TCH)degradation.The ratio of GO in the Fe_(3)O_(4)-GO_(x) composites exhibited different trends of degradation capacity in each AOPs based on different mechanisms.Fe_(3)O_(4)-rGO_(20wt%) exhibited the optimum catalytic performance which enhanced the ozone decomposition efficiency from 33.48%(ozone alone)to 51.83%with the major reactive oxygen species(ROS)of O_(2)·-.In PDS and photo-Fenton processes,Fe_(3)O_(4)-rGO_(5wt%) had the highest catalytic performance in PDS and H_(2)O_(2) decomposition for SO_(4)·–,and·OH generation,respectively.Compared with using PDS alone,PDS decomposition rate and TCH degradation rate could be increased by 5.97 and 1.73 times under Fe_(3)O_(4)-rGO_(5wt%) catalysis.In the photo-Fenton system,Fe_(3)O_(4)-rGO_(5wt%) with the best catalyst performance in H_(2)O_(2) decomposition,and TCH degradation rate increased by 2.02 times compared with blank group.Meantime,the catalytic mechanisms in those systems of that the ROS produced by conversion between Fe^(2+)/Fe^(3+)were also analyzed.展开更多
This paper is concerned with the free vibration analysis of open circular cylindrical shells with either the two straight edges or the two curved edges simply supported and the remaining two edges supported by arbitra...This paper is concerned with the free vibration analysis of open circular cylindrical shells with either the two straight edges or the two curved edges simply supported and the remaining two edges supported by arbitrary classical boundary conditions. Based on the Donnell-Mushtari-Vlasov thin shell theory, an analytical solution of the traveling wave form along the simply supported edges and the modal wave form along the remaining two edges is obtained. With such a unidirectional traveling wave form solution, the method of the reverberation-ray matrix is introduced to derive the equation of natural frequencies of the shell with different classical boundary conditions. The exact solutions for natural frequencies of the open circular cylindrical shell are obtained with the employment of a golden section search algorithm. The calculation results are compared with those obtained by the finite element method and the methods in the available literature. The influence of length, thickness, radius, included angle, and the boundary conditions of the open circular cylindrical shell on the natural frequencies is investigated. The exact calculation results can be used as benchmark values for researchers to check their numerical methods and for engineers to design structures with thin shell components.展开更多
Elucidating the confinement effect harbours tremendous significance for isobutane alkylation with C_(4) olefin.Herein,the confinement effect over zeolite catalysts was elucidated by combining DFT calculations,experime...Elucidating the confinement effect harbours tremendous significance for isobutane alkylation with C_(4) olefin.Herein,the confinement effect over zeolite catalysts was elucidated by combining DFT calculations,experiments(using the novel Beta zeolite exposing only external surfaces(Beta-E)and conventional Beta-I zeolite with both external and internal surfaces)and multi-techniques(e.g.,TGA-DTG,HRTEM,SEM and XRD).It is found that the main active sites for C_(4) alkylation reaction are located on internal surface rather than external surface.On the external surface,the hydride transfer reaction does not occur because the H-shared intermediate cannot be formed without the confinement effect.Moreover,the external surface has stronger selectivity for C_(4) olefin adsorption than isobutane,leading to enhanced oligomerization reactions.Therefore,the suitable micropore with confinement effect is essential for zeolite-catalyzed C_(4) alkylation.The atomic-scale insights of this work are of great referential importance to the design of highly effective zeolite catalyst.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52203209)the State Key Laboratory of Solid Waste Reuse for Building Materials,China(No.SWR-2022-009)the Fundamental Research Funds for the Central Universities,China(No.FRF-IDRY22-012)。
文摘Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are usually toxic and may cause water pollution.In this work,Ag NPs(31.2 nm in diameter)were prepared using the extract of straw,an agricultural waste,as the reducing and stabilizing agent.Experimental analysis revealed that the straw extract contained lignin,the structure of which possesses phenolic hydroxyl and methoxy groups that facilitate the reduction of silver salts into Ag NPs.The surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their aggregation.After the prepared Ag NPs were added to the precursor solution of acrylamide,free radical polymerization was triggered without the need for extra heating or light irradiation,resulting in the rapid formation of an Ag NP-polyacrylamide composite hydrogel.The inhibition zone test proved that the composite hydrogel possessed excellent antibacterial ability due to the presence of Ag NPs.The prepared hydrogel may have potential applications in the fabrication of biomedical materials,such as antibacterial dressings.
基金support from the National Key Research and Development Program of China(2024YFA1207700)National Natural Science Foundation of China(52072141,52102170).
文摘The quantum confinement effect fundamentally alters the optical and electronic properties of quantum dots(QDs),making them versatile building blocks for next-generation light-emitting diodes(LEDs).This study investigates how quantum confinement governs the charge transport,exciton dynamics,and emission efficiency in QD-LEDs,using CsPbI_(3) QDs as a model system.By systematically varying QD sizes,we reveal size-dependent trade-offs in LED performance,such as enhanced efficiency for smaller QDs but increased brightness and stability for larger QDs under high current densities.Our findings offer critical insights into the design of high-performance QD-LEDs,paving the way for scalable and energy-efficient optoelectronic devices.
基金supported in part by the National Natural Science Foundation of China(U2034209)the Postdoctoral Science Foundation of Chongqing(cstc2021jcyj-bsh X0047)+1 种基金the Fundamental Research Funds for the Central Universities(2022CDJJMRH-008)the National Natural Science Foundation of China(62203075)
文摘Dear Editor,This letter focuses on the remaining useful life(RUL)prediction task under limited labeled samples.Existing machine-learning-based RUL prediction methods for this task usually pay attention to mining degradation information to improve the prediction accuracy of degradation value or health indicator for the next epoch.However,they ignore the cumulative prediction error caused by iterations before reaching the failure point.
基金financial support from the National Natural Science Foundation of China(22494710,22408328)supported by Zhejiang Provincial Natural Science Foundation of China(LQN25B060002).
文摘Green hydrogen production by alkaline water electrolysis is an important technology in the decarbonization of the current industry.However,its large-scale application is limited by mediocre performance of conventional Raney Ni electrocatalysts.Herein,high-performance NiMoZn alloy catalysts of the Raney Ni type are developed by pulse electrodeposition for the hydrogen evolution reaction(HER).The optimized catalyst,NMZ-CA,exhibits an overpotential of 37 mV at 10 mA·cm^(-2) and a Tafel slope of 27 mV·dec^(-1) in 1 mol·L^(-1) KOH.Tafel slope measurements,X-ray photoelectron spectroscopy,and H_(2) temperatureprogrammed desorption experiments show that the incorporation of Mo and Zn in Ni weakens the binding of HER intermediate(H_(ads))on strongly adsorbing sites,leading to improved electrochemical kinetics.Electron microscopy and X-ray diffraction study reveals that a phase-pure Mo-doped Ni2Zn11 intermetallic precatalyst formed via pulse electrodeposition and subsequent heat treatment is key to the structure integrity and performance of the catalyst after activation by alkaline leaching.Modificationof NMZ-CA with PTFE enhances its HER performance by facilitating gas removal and improving structure integrity.A practical alkaline water electrolyzer built on the modifiedNMZ/PTFE-CA electrode delivers 2.0 A·cm^(-2) at 1.92 V cell voltage and operates for 250 h without decay.This work provides insights into the synergy between Ni,Mo,and Zn in Raney Ni-type catalysts,and demonstrates the hydrophobic modification as an effective strategy for electrode development in high-performance alkaline water electrolysis.
基金supported by the Applied Basic Research Foundation of Guangdong Province(No.2019A1515110551)the Science Foundation for Distinguished Scholars of Dongguan University of Technology(No.196100041051).
文摘In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(−)][DBUH^(+)],a series of novel heterogeneous dual-ionic poly(ionic liquid)s(PILs)were synthesized readily from 2-(dimethylamino)ethyl methacrylate(DMAEMA),bromo-substituted aliphatic acids,organic bases and divinylbenzene(DVB).The structures,compositions and morphologies were characterized or determined by nuclear magnetic resonance(NMR),thermal gravimetric analysis(TGA),infrared spectroscopy(IR),scanning electron microscopes(SEM),and Brunauer-Emmett-Teller analysis(BET),etc.Application of the P[D+COO^(−)][Br^(−)][DBUH^(+)]series as catalysts in converting CO_(2)into cyclic carbonates showed that P[D+COO^(−)][Br^(−)][DBUH^(+)]-2/1/0.6was able to catalyze epiclorohydrin-CO_(2)cycloaddition the most efficiently.This afforded chloropropylene carbonate(CPC)in 98.4%yield with≥99%selectivity in 24 hr under solvent-and additive-free conditions at atmospheric pressure.Reusability experiments showed that recycling of the catalyst 6 times only resulted in a slight decline in the catalytic performance.In addition,it could be used for the synthesis of a variety of differently substituted cyclic carbonates in good to excellent yields.Finally,key catalytic active sites were probed,and a reasonable mechanism was proposed accordingly.In summary,this work poses an efficient strategy for heterogenization of dual-ionic PILs and provides amild and environmentally benign approach to the fixation and utilization of carbon dioxide.
基金supported by the Higher Education Scientific Research Project of the Anhui Province(Natural Sciences)(2023AH051039)Anhui Provincial Natural Resources Science and Technology Project(2023-K-4)+1 种基金the National Key Research&Development Program of China(2023YFD1902300)Anhui Provincial Natural Science Foundation(2108085QC123).
文摘Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.
基金Zhejiang Provincial Natural Science Foundation of China(Nos.LR24B020003 and LQ24B020003)Science and Technology Project of Taizhou City(No.24gyb17)for financial support。
文摘New water-soluble fluorescent tetracationic imidazolium-based macrocycles are synthesized via a modular SN2 nucleophilic substitution reaction.The positive charge and acidic C-H sites of these macrocycles enable them to bind with nucleotides in water,driven by hydrogen bonds and electrostatic interactions.The binding is high affinity for suitable nucleotides.These properties position them as promising candidates for the selective sensing of nucleotides.
基金financial support from the Shenzhen Key Laboratory of Intelligent Robotics Flexible and Manufacturing Systems(Grant No.ZDSYS20220527171403009)the Shenzhen Science and Technology Innovation Commission(Grant No.20231115111658002).
文摘Gallium oxide(Ga_(2)O_(3))is a promising material for next-generation power devices due to its ultrawide bandgap and extremely high critical electric field strength;however,the strong anisotropy and cleavage tendency of Ga_(2)O_(3)pose significant challenges for high-precision surface processing.In this work,a systematic study was conducted through tribological analysis of monocrystalline(001)β-Ga_(2)O_(3).Initially,reciprocal sliding tests were conducted onβ-Ga_(2)O_(3)along different crystallographic directions,[100]and[010].The results revealed that the[100]direction was more wear resistant,while the[010]direction was more prone to failure.Indentation experiments on(001)β-Ga_(2)O_(3)showed extensive slip and cleavage cracking along different crystallographic orientations,indicating that mechanical wear might dominate the wear mode of this material.Subsequently,sliding tests under various environmental conditions revealed that the wear rate was correlated with humidity.Additionally,β-Ga_(2)O_(3)exhibited time-dependent frictional behavior,with its coefficient of friction stabilizing around 0.1,0.5,and 0.9 at different stages during the wear test.These findings indicate that the frictional behavior of Ga_(2)O_(3)is closely linked to the state of its surface.This study provides critical insights into the tribological behavior of Ga_(2)O_(3)and offers guidance for ultraprecision machining of this material.
基金supported by the National Natural Science Foundation of China(Grant No.62204245,U23A200098)Baima Lake Laboratory Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(Grant No.LBMHD24E020002)+4 种基金Key Research and Development Program of Zhejiang Province(Grant No.2022C01215,2024C01092)China Postdoctoral Science Foundation(Grant No.2023M743620,2024T170960)Key Research and Development Program of Ningbo(Grant No.2023Z151)National Key Research and Development Program of China(Grant No.2024YFB3817304)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY24F040003).
文摘Despite significant advancements in the power conversion efficiency(PCE)of perovskite/silicon tandem solar cells,improving carrier management in top cells remains challenging due to the defective dual interfaces of wide-bandgap perovskite,particularly on textured silicon surfaces.Herein,a series of halide ions(Cl^(-),Br^(-),I^(-))substituted piperazinium salts are designed and synthesized as post-treatment modifiers for perovskite surfaces.Notably,piperazinium chloride induces an asymmetric bidirectional ions distribution from the top to the bottom surface,with large piperazinium cations concentrating at the perovskite surface and small chloride anions migrating downward to accumulate at the buried interface.This results in effective dual-interface defect passivation and energy band modulation,enabling wide-bandgap(1.68 eV)perovskite solar cells to achieve a PCE of 22.3%and a record product of open-circuit voltage×fill factor(84.4%relative to the Shockley-Queisser limit).Furthermore,the device retains 91.3%of its initial efficiency after 1200 h of maximum power point tracking without encapsulation.When integrated with double-textured silicon heterojunction solar cells,a remarkable PCE of 31.5%is achieved for a 1.04 cm^(2) monolithic perovskite/silicon tandem solar cell,exhibiting excellent long-term operational stability(T_(80)=755 h)without encapsulation in ambient air.This work provides a convenient strategy on dual-interface engineering for making high-efficiency and stable perovskite platforms.
基金supported by the National Natural Science Foundation of China(No.82322075)。
文摘Objective:Ulcerative colitis is closely associated with intestinal stem cell(ISC)loss and impaired intestinal mucus barrier.Sinisan(SNS),a compound Chinese herbal medicine,has a long history in the treatment of intestinal dysfunction,yet whether SNS can relieve acute experimental colitis by modulating ISC proliferation and secretory cell differentiation has not been studied.Our study tested the effect of SNS against acute colitis and focused on the mechanisms involving intestinal barrier recovery.Methods:Network pharmacology analysis and blood entry component analysis of SNS were used to explore the underlying mechanism by which SNS affects the acute dextran sulfate sodium(DSS)-induced murine colitis model.RNA-sequencing was used to demonstrate the mechanism.Further,reverse transcription-quantitative polymerase chain reaction,immunofluorescence staining,and alcian blue and periodic acid-Schiff staining were performed in vivo and in the colonic organoids to investigate the cell lineage differentiation-related mechanism of SNS.Furthermore,potential active ingredients from SNS were predicted by network pharmacology analysis.Results:SNS dramatically suppressed DSS-induced acute colonic inflammation in mice.RNA-sequencing analysis revealed downregulation of inflammation and apoptosis-related genes,and upregulation of lipid metabolism and proliferation-related genes,such as Irf7,Ppara,Clspn and Hspa5.Additionally,ISC renewal and intestinal secretory cell lineage commitment were significantly promoted by SNS both in vivo and in vitro in colonic organoids,leading to enhanced mucin expression.Furthermore,potential active ingredients from SNS that mediated inflammation,lipid metabolism,proliferation,apoptosis,stem cells and secretory cells were predicted using a network pharmacology approach.Conclusion:Our study shed light on the underlying mechanism of SNS in attenuating acute colitis from the perspective of ISC renewal and secretory lineage cell differentiation,suggesting a of novel therapeutic strategy against colitis.
基金Supported by grants from Innovative Team Project of Jiangsu Province,China,No.CXZZ11_0705
文摘AIM:To investigate the biological role of mi R-1290 in esophageal squamous cell carcinoma(ESCC) progression and invasion and the underlying mechanism.METHODS:Quantitative real-time polymerase chain reaction(q RT-PCR) was performed to evaluate mi R-1290 expression in ESCC tissue samples.The roles of mi R-1290 in cell proliferation,migration and invasion were identified using mi R-1290 mimic-transfected cells.In addition,the regulatory effect of mi R-1290 on suppressor of cancer cell invasion(SCAI) was evaluated using q RT-PCR,Western blot analysis and a dual luciferase reporter assay.RESULTS:mi R-1290 was significantly upregulated in ESCC tissue samples compared with normal adjacent tissues(9.213 ± 1.150 vs 1.000 ± 0.0),(P < 0.01).Upregulation of mi R-1290 was associated with tumor differentiation(P = 0.021),N classification(P = 0.006) and tumor-node-metastasis stage(P = 0.021) in ESCC patients.Moreover,ectopic mi R-1290 expression potently promoted ESCC cell growth(P < 0.01),migration(P < 0.01) and invasion(P < 0.01) in vitro.mi R-1290 overexpression in ESCC cell lines decreased SCAI expression at the translational level and reduced SCAI-driven luciferase-reporter activity(P < 0.01).CONCLUSION:Our findings suggested that mi R-1290 may play an oncogenic role in cellular processes of ESCC.
文摘Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. WB-DWI was performed by using short TI inversion recovery echo-planar imaging sequence with free breathing and built-in body coil. Axial T2- weighted imaging images of the same location were used as reference. The results of WB-DWI were compared with pathological results and other imaging modalities. The mean apparent diffusion coefficient （ADC） values of different kinds of lymph nodes were compared. Results WB-DWI was positive in all 18 cases with lymphoma, 5 cases with metastatic lymph nodes and 4 of 8 eases with benign lymphadenopathy. The mean ADC value of lymphomatous, metastatic and benign lymph nodes was （0.87 ± 0.17） × 10^3, （0.98± 0.09） × 10^3 and （1.20 ± 0.10） × 10^3 mm^2/s. There was significant difference in ADC value between benign lymph nodes and other two groups （P 〈 0.01）. The sensitivity, specificity and accuracy of WB-DWI in diagnosis of lymphoma were 100% （18/18）, 30.8% （4/13） and 71.0% （22/31）. When an ADC value of 1.08 × 10^-3 mm^2/s was used as the threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with sensitivity of 87.8% and specificity of 91.3%. Sixteen of eighteen cases （88.9%） of lymphoma were accurately staged in accordance with clinical staging. Conclusions WB-DWI is a sensitive, but less specific technique for diagnosis of lymphoma. It is difficult to differentiate lymphnmatous from metastatic lymph nodes using WB-DWI. However, it is a valuable imaging modality for staging of patients with malignant lymphoma.
文摘Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cervical cancer by cervical biopsy and 24 female patients with other suspected pelvic abnormalities received preoperative body DWI scan. Results of body DWI were compared with pathological findings. The apparent diffusion coefficient (ADC) values of normal cervix and different pathological types of cervical cancer were compared. ADC value of normal or inflammatory lymph nodes was also compared with that of metastatic ones. Student's t test was used for statistical analysis. Results There were 5 adenocarcinomas and 19 epitheliomas showed with biopsy results, and DWI showed 21 cervical lesions out of them (87.5%). ADC values of the normal cervix (n = 24), epithelioma (n = 19), and adenocar- cinoma (n = 5) were (1.73 ± 0.31) ×10-3, (0.88 ± 0.22) ×10-3, and (1.08 ± 0.12) ×10-3 mm2/s, respectively. Statistical analysis showed significant difference in ADC value between normal cervical tissue and either tumor tissues (both P < 0.01). In patients had lymphadenectomy (n = 24), totally 67 lymph nodes including 16 metastatic lymph nodes were pathologically analyzed, and DWI showed 66 (98.5%) out of them. ADC values of normal/inflammatory and metastatic lymph nodes were (1.07 ± 0.16) ×10-3 and (0.77 ± 0.13) ×10-3 mm2/s (P < 0.01). Receiver operating characteristic (ROC) curve of ADC value of metastatic lymph node showed that area under curve was 0.961. Conclusions ADC value in cervical carcinoma is lower than that in normal cervix, and ADC may have predictive value in subtype discrimination. ADC value may improve the preoperative characterization of lymph node metastasis. And at least abdominal and pelvic DWI scan is suggested for N staging evaluation in such patients.
基金supported by the National Natural Science Foundation of China(No.51108444)the Key Research and Development Plan of the Ministry of Science and Technology(No.2019YFD1100104)。
文摘Coagulation and precipitation is a widely applied method to remove F-from wastewater.In this work,the effect of coagulation on the removal of F-and organic matter from coking wastewater was studied using Al Cl3and Fe Cl3as compound coagulants.The removal rates of F-and organic matter under different coagulant doses and p H conditions were investigated.The results show that the highest removal rates of F-by Al Cl3and Fe Cl3are 94.4%and 25.4%,respectively;when the dosage is 10 mmol/L,the TOC removal rates of Fe Cl3and Al Cl3reach 20.4%and 34.7%,respectively.Therefore,the removal rate of F-by Al Cl3is higher than that of Fe Cl3,but the removal rate of organic matter by Fe Cl3is relatively higher.The addition of Ca2+can promote the removal of F-,but the removal rate of organic matter decreases.In addition,by investigating the effects of different p H and Fe–Al ratio on the removal rate,the removal effect of adding Fe Cl3and Al Cl3at the same time was discussed.The results show that the most suitable working condition for the removal of organic matter and F-is that the p H is 6.5 and the molar ratio of Al/Fe is 8:2.Overall,the removal mechanism of F-and organic matter in coking wastewater by Fe Cl3and Al Cl3was explored in this study.The experimental results can provide reference for the advanced treatment of coking wastewater.
基金supported by the National Natural Science Foundation of China(Nos.21906088,51902169,52170039)the National Science Foundation for Post-doctoral Scientists of China(No.2021T140165)+2 种基金the Heilongjiang Provincial Natural Science Foundation of China(No.LH2020B023)Department of Education Heilongjiang Province(Nos.135309338,135309351)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(Nos.UNPYSCT-2020068,UNPYSCT-2020067).
文摘Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.This review intends to summarize the timely references and insights for the recent advances in MOFs that are used in AOPs.Starting with the preparation methodologies,including conventional hydrothermal method,electrochemical method,sol-gel method,and emerging microwave and ultrasound assisted synthesis methods.Application and mechanism for MOFs using in various AOPs of Fenton-like,photocatalysis,catalytic ozonation,persulfate catalysis and other emerging oxidation methods are emphatically discussed.We hope this review can comprehensively summarize the research and application progress of MOFs in AOPs,deepen the understanding of the catalytic mechanisms.
文摘A new acylated flavonoid glycoside, 3-O-kaempferol-3-O-acetyl-6-O-(p-coumaroyl)-- D-glucopyranoside 1 was isolated from the whole plant of Anaphalis aureo-punctata. The structure was established by spectral methods.
基金supported by the National Natural Science Foundation ofChina(No.21072130)
文摘Bromination is used as a strategy to improve biological activity in medicinal chemistry.In order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one scaffold,based on our previous work and molecular modeling,a series of novel 3-aryl-6-（bromoarylrnethyl）-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were designed by molecular docking,synthesized and characterized by mass spectra,infrared spectra,proton NMR and elemental analyses.The study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive control.Most of all target compounds exhibited more than 45%inhibition at 10μmol/L.The preliminary structureactivity relationship was the bromine atoms and the hydroxyl group at the phenyl ring at the C6 position of the parent nucleus played significant roles in the AChE inhibitory activity of the target compounds.
基金supported by the National Natural Science Foundation of China(Nos.21906088,51902169,52170039)the National Science Foundation for Post-doctoral Scientists of China(No.2021T140165)+3 种基金the Natural Science Foundation of Heilongjiang Province,China(No.LH2020B023)Department of Education Heilongjiang Province(No.135309338)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(Nos.UNPYSCT-2020068,UNPYSCT-2020067)the financial support by the Heilongjiang Provincial Key Laboratory of Surface Active Agent and Auxiliary(No.BMHXJKF009)。
文摘This study explored the catalytic mechanism and performance impacted by the materials ratio of Fe_(3)O_(4)-GO_(x) composites in three typical advanced oxidation processes(AOPs)of O_(3),peroxodisulfate(PDS)and photo-Fenton processes for tetracycline hydrochloride(TCH)degradation.The ratio of GO in the Fe_(3)O_(4)-GO_(x) composites exhibited different trends of degradation capacity in each AOPs based on different mechanisms.Fe_(3)O_(4)-rGO_(20wt%) exhibited the optimum catalytic performance which enhanced the ozone decomposition efficiency from 33.48%(ozone alone)to 51.83%with the major reactive oxygen species(ROS)of O_(2)·-.In PDS and photo-Fenton processes,Fe_(3)O_(4)-rGO_(5wt%) had the highest catalytic performance in PDS and H_(2)O_(2) decomposition for SO_(4)·–,and·OH generation,respectively.Compared with using PDS alone,PDS decomposition rate and TCH degradation rate could be increased by 5.97 and 1.73 times under Fe_(3)O_(4)-rGO_(5wt%) catalysis.In the photo-Fenton system,Fe_(3)O_(4)-rGO_(5wt%) with the best catalyst performance in H_(2)O_(2) decomposition,and TCH degradation rate increased by 2.02 times compared with blank group.Meantime,the catalytic mechanisms in those systems of that the ROS produced by conversion between Fe^(2+)/Fe^(3+)were also analyzed.
基金Project supported by the National Natural Science Foundation of China （Nos. 51209052, 51279038, and 51479041）, the Natural Sci- ence Foundation of Heilongjiang Province （No. QC2011C013）, and the Opening Funds of State Key Laboratory of Ocean Engineering of Shanghai Jiao Tong University （No. 1307）, China
文摘This paper is concerned with the free vibration analysis of open circular cylindrical shells with either the two straight edges or the two curved edges simply supported and the remaining two edges supported by arbitrary classical boundary conditions. Based on the Donnell-Mushtari-Vlasov thin shell theory, an analytical solution of the traveling wave form along the simply supported edges and the modal wave form along the remaining two edges is obtained. With such a unidirectional traveling wave form solution, the method of the reverberation-ray matrix is introduced to derive the equation of natural frequencies of the shell with different classical boundary conditions. The exact solutions for natural frequencies of the open circular cylindrical shell are obtained with the employment of a golden section search algorithm. The calculation results are compared with those obtained by the finite element method and the methods in the available literature. The influence of length, thickness, radius, included angle, and the boundary conditions of the open circular cylindrical shell on the natural frequencies is investigated. The exact calculation results can be used as benchmark values for researchers to check their numerical methods and for engineers to design structures with thin shell components.
基金supported by the National Natural Science Foundation of China(21978325,21776312,21908186)the Independent Innovation Foundation of Qingdao(17-1-1-18-jch)+1 种基金the Fundamental Research Funds for the Central Universities(18CX02014A)the Fundamental Research Funds for the Central Universities and the Opening Fund of State Key Laboratory of Heavy Oil Processing(SKLOP202003002).
文摘Elucidating the confinement effect harbours tremendous significance for isobutane alkylation with C_(4) olefin.Herein,the confinement effect over zeolite catalysts was elucidated by combining DFT calculations,experiments(using the novel Beta zeolite exposing only external surfaces(Beta-E)and conventional Beta-I zeolite with both external and internal surfaces)and multi-techniques(e.g.,TGA-DTG,HRTEM,SEM and XRD).It is found that the main active sites for C_(4) alkylation reaction are located on internal surface rather than external surface.On the external surface,the hydride transfer reaction does not occur because the H-shared intermediate cannot be formed without the confinement effect.Moreover,the external surface has stronger selectivity for C_(4) olefin adsorption than isobutane,leading to enhanced oligomerization reactions.Therefore,the suitable micropore with confinement effect is essential for zeolite-catalyzed C_(4) alkylation.The atomic-scale insights of this work are of great referential importance to the design of highly effective zeolite catalyst.
