Research the evaporating crystalization process of the magnesium sulfate subtypes brine at high temperature from Dalangtan salt lake in Qinghai province.It was revealed that the salt lake is a typical subtype magnesium
Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechan...Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechanism. When compared to the crystal thickness (d(c)), the volume occupied by the chain in the melts i.e., the radius of gyration (R-g), plays a very important role in polymer crystallization. When d(c) less than or equal to R-g, crystallization does not necessitate a chain disentangling. The entanglements are just shifted into the amorphous regions. However, as d(c)>R-g, i.e., as the crystal thickness gets larger than the radius of gyration of the chain in the melt, it becomes necessary for a chain to disentangle. Then a change of crystallization mechanism occurs. Such change has been experimentally observed in the crystallization of poly(I-butene). A change in the crystal morphologies from spherulite to quadrangle, is seen via PLM, as crystallization temperatures increase. Even more, such a change is molecular weight dependent, and shifts to lower temperature as molecular weight decreases. There exists a jump of crystal thickness and crystallinity associated with morphological change, as seen via SAXS. A change of crystallization kinetics and crystallinity is further evidenced via dilatometry. The unique feature of P1b crystallization has been discussed based on the radius of gyration of chain in the melt (R-g), and very good agreement is obtained.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the correspo...This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.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
An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mod...An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.展开更多
The Ni/SBA-15 catalysts were synthesized using the in situ method and the influence of crystallization temperature on nickel utilization efficiency-a critical factor in mesoporous material design-was systematically in...The Ni/SBA-15 catalysts were synthesized using the in situ method and the influence of crystallization temperature on nickel utilization efficiency-a critical factor in mesoporous material design-was systematically investigated.The structural characteristics and nickel anchoring capacity were analyzed using XRD,BET,FT-IR,H2-TPR,and ICP-OES.The results demonstrated that the crystallization temperature significantly affected the framework order of SBA-15 and the surface anchoring efficiency of Ni ions.The nickel utilization efficiency increased from 8.4%at 80℃ to 60.49%at 140℃,but then decreased to 47.25%at 160℃,indicating an optimal crystallization temperature window.This provides crucial guidance for tailoring high-performance metal-doped molecular sieves.The optimal catalyst exhibited excellent performance in the hydrogenation of 1,4-butynediol(BYD):the BYD conversion reached 97.25%with 88.99%selectivity of 1,4-butenediol(BED)within 5 h,and reached 99.73%with 87.34%selectivity of 1,4-butanediol(BDO)after 20 h reaction.These results revealed the critical role of crystallization temperature in metal utilization and provided theoretical support for designing highly active molecular sieve catalysts.展开更多
Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2...Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2)O(1)was synthesized as a 2D structure using Coas the metal source,methanol‑water(4∶6,V/V)as the solvent,and specific concentrations of 2,5‑furandicarboxylic acid(H_(2)FDCA)and 1,3,5‑triimidazole benzene(L).Adjusting to pure water and lowering the concentration of L yielded the 1D chain structure of[Co(HL)2(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(2).Using Cu(Ⅱ)as the metal source,methanol/water(9∶1,V/V)as the solvent,and specific concentrations of L and H2FDCA,the 1D chain structure of[Cu(L)(FDCA)(H_(2)O)]·2H_(2)O(3)was synthesized.Upon increasing the concentrations of L and H2FDCA,and switching the solvent to pure water,the 1D chain structure of[Cu(HL)_(2)(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(4)was obtained.This shows that changing the solvent and ligand concentrations can affect the structural changes of CPs.In addition,the solid‑state photoluminescence of CPs 1‑4 at room temperature was studied,and their morphological changes were observed via scanning electron microscopy.Density functional theory calculations revealed that the negative charge concentrates on the O and N atoms of the ligand,facilitating ligand‑metal ion coordination.CCDC:2403934,1;2403935,2;2403936,3;2403938,4.展开更多
In 2024,the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas.In controllable catalytic polymerization,organoboron ca...In 2024,the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas.In controllable catalytic polymerization,organoboron catalysts were developed for CO₂copolymerization and novel photoresist materials.Studies in microstructure and rheology elucidated universal deformation modes in graphene-based 2D membranes and improved graphene fiber properties through shear alignment engineering,defect control,and enhanced interlayer entanglement.For separating functional polymers,Janus membranes and channels were created for multiphase separation,liquid-phase molecular layer-by-layer deposition technique was developed to fabricate aromatic polyamide nanofilms,and the harmonic amide bond density was established as a valuable parameter for polyamide structural analysis.In biomedical functional polymers,a sustainable carboxyl-ester transesterification strategy was proposed for upcycling poly(ethylene terephthalate)(PET)waste into biodegradable plastics.Additionally,immunocompatible biomaterials were designed utilizing zwitterionic polypeptides and albumin-derived coatings,and Cu2+-phenolic nanoflower was designed to combat fungal infections by combining cuproptosis and cell wall digestion.Further,the researchers developed a gelatin-DOPA-knob/fibrinogen hydrogel to achieve rapid and robust hemostatic sealing,utilized a double-network polyelectrolyte-coated hydrogel for enhancing endothelialization of left atrial appendage(LAA)occluders,and the researchers also demonstrated that image-guided high-intensity focused ultrasound enables manipulation of shape-memory polymers.Finally,in the realm of photo-electro-magnetic functional polymers,precise control of through-space conjugation was shown to enhance organic luminescence.Topologically structured hydrogels were revealed to exhibit autonomous actuation.Also,solar-driven photothermal ion pumps were developed for selective lithium extraction from seawater,and high-performance non-solvated C60 single-crystal films were prepared via facile bar coating.Lastly,the researchers demonstrated outstanding dielectric properties of polyethylene(PE)lamellar single crystals.The relevant works are reviewed in this paper.展开更多
In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,cry...In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.展开更多
Driven by the rapid advancement of wind,solar,and electric vehicle technologies,the global copper demand has increased significantly,prompting greater attention to complex and refractory copper-bearing minerals.As a r...Driven by the rapid advancement of wind,solar,and electric vehicle technologies,the global copper demand has increased significantly,prompting greater attention to complex and refractory copper-bearing minerals.As a representative example,valleriite is widely distributed in Cu-Ni sulfide ores and regarded as the second-most important copper-bearing phase after chalcopyrite.Structurally,valleriite features a layered crystal lattice composed of alternating hydrophobic sulfide and hydrophilic hydroxide layers,imparting it characteristics intermediate between sulfide and oxide ores.This unique structure,combined with its fine grain size,poor crystallinity,and complex intergrowths,greatly limits the efficiency of conventional beneficiation methods,such as flotation and magnetic separation.This review systematically summarizes the global distribution and physicochemical properties of valleriite and critically assesses beneficiation studies reported over the past seven decades.Furthermore,key factors contributing to poor recovery are identified,and potential strategies for improving the processing of valleriite-bearing ores are proposed.展开更多
Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing struc...Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa_(2)(SeO_(3))_(4) and Hg_(2)Ga(Se_(O)_(3))_(2)F.HgGa_(2)(SeO_(3))_(4) crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg_(2)Ga(Se_(O)_(3))_(2)F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg_(2)O_(2),its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa_(2)(SeO_(3))_(4).Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg_(2)Ga(Se_(O)_(3))_(2)F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.展开更多
Understanding the photoluminescence(PL)mechanism of metal nanoclusters from both molecular and supramolecular perspectives is crucial for developing highly emissive cluster-based nanomaterials.In this study,we synthes...Understanding the photoluminescence(PL)mechanism of metal nanoclusters from both molecular and supramolecular perspectives is crucial for developing highly emissive cluster-based nanomaterials.In this study,we synthesized two structurally similar Ag14 nanoclusters with different phosphine stabilizers,which demonstrated opposite PL behaviors in solution and crystalline states.The Ag14 nanocluster stabilized by P(Ph-OMe)_(3) ligands exhibited a higher PL intensity compared to the one stabilized by P(Ph-F)_(3) ligands,which was attributed to the stronger electron-donating ability of the P(Ph-OMe)_(3) ligand that improved ligand-to-metal charge transfer efficiency.In contrast,the P(Ph-F)_(3) stabilized Ag14 crystals displayed greater PL intensity than the Ag14 cluster crystal with a-OMe surface,which was due to stronger intermolecular interactions within the cluster lattice of the former that limited non-radiative energy loss and thus enhanced PL.Overall,this work aims to promote a comprehensive understanding of the fluorescence in cluster-based nanomaterials,which will be beneficial for their downstream applications.展开更多
Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical pr...Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.展开更多
Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregat...Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregation of small-molecule acceptors.This work pioneers a kinetic paradigm for resolving the crystallinity-domain size trade-off in organic photovoltaics through dual-additive-guided stepwise crystallization.By strategically pairing 1,2-dichlorobenzene(o-DCB,low binding energy to Y6)and 1-fluoronaphthalene(FN,high binding energy),we achieve temporally decoupled crystallization control:o-DCB first mediates donor-acceptor co-crystallization during film formation,constructing a metastable network,whereupon FN induces confined Y6 crystallization within this framework during thermal annealing,refining nanostructure without over-aggregation.Morphology studies reveal that this synergy enhances crystallinity of(100)diffraction peaks by 21%–10%versus single-additive controls(o-DCB/FN alone),while maintaining optimal domain size.These morphological advantages yield balanced carrier transport(μh/μe=1.23),near-unity exciton dissociation(98.53%),and a champion power conversion efficiency(PCE)of 18.08%for PM6:Y6,significantly surpassing single-additive devices(o-DCB:17.20%;FN:17.53%).Crucially,the dual-additive strategy demonstrates universal applicability across diverse active layer systems,achieving an outstanding PCE of 19.27%in PM6:L8-BO-based devices,thereby establishing a general framework for morphology control in high-efficiency OPVs.展开更多
Pb-Sn mixed perovskite solar cells(PSCs)are crucial components for realizing efficient all-perovskite tandem devices.However,their efficiency and stability are severely limited by oxidative degradation(Sn^(4+)formatio...Pb-Sn mixed perovskite solar cells(PSCs)are crucial components for realizing efficient all-perovskite tandem devices.However,their efficiency and stability are severely limited by oxidative degradation(Sn^(4+)formation)and metallic defects(Sn^(0)/Pb^(0)).In addition,the rapid and uncontrolled Sn^(2+)nucleation kinetics result in nonuniform crystallization.Herein,we introduce a natural redox shuttle glutathione(GSH)in Pb-Sn mixed PSCs,achieving regenerable antioxidation and crystallization regulation simultaneously.The reversible redox reactions between GSH and glutathione disulfide(GSSG)enable the self-healing of Sn^(4+)and Sn^(0)/Pb^(0)impurities,creating a regenerable antioxidation protective shell at the perovskite interfaces.Meanwhile,the strong coordination between GSH and perovskite regulates the crystallization process,optimizing the nucleation and crystallization kinetics.Furthermore,the GSH incorporation creates a high-quality charge separation junction at the perovskite/hole transport layer,facilitating carrier separation and extraction.The optimized Pb-Sn PSCs exhibit impressive power conversion efficiencies(PCEs)of up to 23.71%.The champion all-perovskite tandem PSCs with GSH achieve a PCE of 28.49%and retain 90%of the initial PCE after 560 h of continuous illumination.This work establishes a new nature-inspired redox shuttling strategy and elucidates its working mechanism,advancing the development of efficient and stable all-perovskite tandem solar cells.展开更多
A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi veloci...A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.展开更多
Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_...Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.展开更多
The mechanical performance of exceedingly soft materials such as Ag is significantly influenced by various working conditions.Therefore,this study systematically investigates the effects of crack geometry,substrate cr...The mechanical performance of exceedingly soft materials such as Ag is significantly influenced by various working conditions.Therefore,this study systematically investigates the effects of crack geometry,substrate crystal orientation,and indenter shape on crack propagation.The mechanical response of Ag is analyzed using the quasi-continuum(QC)method.A pre-crack with a predefined depth and angle was introduced to initiate fracture behavior.The results show that when the pre-crack height is 50 A,the crack propagates rapidly as the imprint depth increases from0 to 7 A,grows steadily up to 15 A,and then accelerates sharply between 15 and 20 A.For other pre-crack heights,crack propagation occurs at a relatively faster rate.Substrates with[100],[010],and[001]crystal orientations promote crack extension,while the onset of plastic deformation(referred to as the yield point in this study)and the fracture strength both increase with increasing pre-crack height.The yield point,fracture strength,and stress intensity factors are highly sensitive to the pre-crack height.When the pre-crack angle is 90○,the fracture strength reaches its maximum of 0.2%higher than that of the uncracked sample-whereas at 0○,it reaches its minimum,still 53.8%higher than that of the uncracked sample.The sample model is conducted using AutoCAD software.The optimized quasicontinuum(QC)method is used to investigate the effects of different crack geometries,substrate crystal orientations,and indenter shapes on the crack extension of Ag material.Baskes and Dow(FBD)potential is borrowed to describe the interaction forces between Ag-Ag,Ni-Ag,and Ni-Ni.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
基金financially supported with General Project of Nat-ural Science Foundation of China (No. 21373252)
文摘Research the evaporating crystalization process of the magnesium sulfate subtypes brine at high temperature from Dalangtan salt lake in Qinghai province.It was revealed that the salt lake is a typical subtype magnesium
基金This work was supported by the Deutsche Forschungsgemeinschall and der Chemischen Industrierate, Alexander von Humboldt Stiffeng and the China National Distinguished Young Investigator Fund (No. 29925413).
文摘Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechanism. When compared to the crystal thickness (d(c)), the volume occupied by the chain in the melts i.e., the radius of gyration (R-g), plays a very important role in polymer crystallization. When d(c) less than or equal to R-g, crystallization does not necessitate a chain disentangling. The entanglements are just shifted into the amorphous regions. However, as d(c)>R-g, i.e., as the crystal thickness gets larger than the radius of gyration of the chain in the melt, it becomes necessary for a chain to disentangle. Then a change of crystallization mechanism occurs. Such change has been experimentally observed in the crystallization of poly(I-butene). A change in the crystal morphologies from spherulite to quadrangle, is seen via PLM, as crystallization temperatures increase. Even more, such a change is molecular weight dependent, and shifts to lower temperature as molecular weight decreases. There exists a jump of crystal thickness and crystallinity associated with morphological change, as seen via SAXS. A change of crystallization kinetics and crystallinity is further evidenced via dilatometry. The unique feature of P1b crystallization has been discussed based on the radius of gyration of chain in the melt (R-g), and very good agreement is obtained.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
文摘This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.
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.
文摘An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.
文摘The Ni/SBA-15 catalysts were synthesized using the in situ method and the influence of crystallization temperature on nickel utilization efficiency-a critical factor in mesoporous material design-was systematically investigated.The structural characteristics and nickel anchoring capacity were analyzed using XRD,BET,FT-IR,H2-TPR,and ICP-OES.The results demonstrated that the crystallization temperature significantly affected the framework order of SBA-15 and the surface anchoring efficiency of Ni ions.The nickel utilization efficiency increased from 8.4%at 80℃ to 60.49%at 140℃,but then decreased to 47.25%at 160℃,indicating an optimal crystallization temperature window.This provides crucial guidance for tailoring high-performance metal-doped molecular sieves.The optimal catalyst exhibited excellent performance in the hydrogenation of 1,4-butynediol(BYD):the BYD conversion reached 97.25%with 88.99%selectivity of 1,4-butenediol(BED)within 5 h,and reached 99.73%with 87.34%selectivity of 1,4-butanediol(BDO)after 20 h reaction.These results revealed the critical role of crystallization temperature in metal utilization and provided theoretical support for designing highly active molecular sieve catalysts.
文摘Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2)O(1)was synthesized as a 2D structure using Coas the metal source,methanol‑water(4∶6,V/V)as the solvent,and specific concentrations of 2,5‑furandicarboxylic acid(H_(2)FDCA)and 1,3,5‑triimidazole benzene(L).Adjusting to pure water and lowering the concentration of L yielded the 1D chain structure of[Co(HL)2(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(2).Using Cu(Ⅱ)as the metal source,methanol/water(9∶1,V/V)as the solvent,and specific concentrations of L and H2FDCA,the 1D chain structure of[Cu(L)(FDCA)(H_(2)O)]·2H_(2)O(3)was synthesized.Upon increasing the concentrations of L and H2FDCA,and switching the solvent to pure water,the 1D chain structure of[Cu(HL)_(2)(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(4)was obtained.This shows that changing the solvent and ligand concentrations can affect the structural changes of CPs.In addition,the solid‑state photoluminescence of CPs 1‑4 at room temperature was studied,and their morphological changes were observed via scanning electron microscopy.Density functional theory calculations revealed that the negative charge concentrates on the O and N atoms of the ligand,facilitating ligand‑metal ion coordination.CCDC:2403934,1;2403935,2;2403936,3;2403938,4.
基金supported by the Fundamental Research Funds for the Central Universities(No.226-2025-00031).
文摘In 2024,the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas.In controllable catalytic polymerization,organoboron catalysts were developed for CO₂copolymerization and novel photoresist materials.Studies in microstructure and rheology elucidated universal deformation modes in graphene-based 2D membranes and improved graphene fiber properties through shear alignment engineering,defect control,and enhanced interlayer entanglement.For separating functional polymers,Janus membranes and channels were created for multiphase separation,liquid-phase molecular layer-by-layer deposition technique was developed to fabricate aromatic polyamide nanofilms,and the harmonic amide bond density was established as a valuable parameter for polyamide structural analysis.In biomedical functional polymers,a sustainable carboxyl-ester transesterification strategy was proposed for upcycling poly(ethylene terephthalate)(PET)waste into biodegradable plastics.Additionally,immunocompatible biomaterials were designed utilizing zwitterionic polypeptides and albumin-derived coatings,and Cu2+-phenolic nanoflower was designed to combat fungal infections by combining cuproptosis and cell wall digestion.Further,the researchers developed a gelatin-DOPA-knob/fibrinogen hydrogel to achieve rapid and robust hemostatic sealing,utilized a double-network polyelectrolyte-coated hydrogel for enhancing endothelialization of left atrial appendage(LAA)occluders,and the researchers also demonstrated that image-guided high-intensity focused ultrasound enables manipulation of shape-memory polymers.Finally,in the realm of photo-electro-magnetic functional polymers,precise control of through-space conjugation was shown to enhance organic luminescence.Topologically structured hydrogels were revealed to exhibit autonomous actuation.Also,solar-driven photothermal ion pumps were developed for selective lithium extraction from seawater,and high-performance non-solvated C60 single-crystal films were prepared via facile bar coating.Lastly,the researchers demonstrated outstanding dielectric properties of polyethylene(PE)lamellar single crystals.The relevant works are reviewed in this paper.
基金Funded by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.
基金supported by the Key Research and Development Special Project of Xinjiang Uygur Autonomous Region of China(No.2024B040029)the National Natural Science Foundation of China(No.52204301)the Hunan Province Graduate Student Independent Exploration Project,China(No.1053320220682).
文摘Driven by the rapid advancement of wind,solar,and electric vehicle technologies,the global copper demand has increased significantly,prompting greater attention to complex and refractory copper-bearing minerals.As a representative example,valleriite is widely distributed in Cu-Ni sulfide ores and regarded as the second-most important copper-bearing phase after chalcopyrite.Structurally,valleriite features a layered crystal lattice composed of alternating hydrophobic sulfide and hydrophilic hydroxide layers,imparting it characteristics intermediate between sulfide and oxide ores.This unique structure,combined with its fine grain size,poor crystallinity,and complex intergrowths,greatly limits the efficiency of conventional beneficiation methods,such as flotation and magnetic separation.This review systematically summarizes the global distribution and physicochemical properties of valleriite and critically assesses beneficiation studies reported over the past seven decades.Furthermore,key factors contributing to poor recovery are identified,and potential strategies for improving the processing of valleriite-bearing ores are proposed.
基金supported by the National Natural Science Foundation of China(Nos.22475215,22031009 and 21921001)the NSF of Fujian Province(Nos.2023J01216,2024J010039)the Selfdeployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-GH06).
文摘Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa_(2)(SeO_(3))_(4) and Hg_(2)Ga(Se_(O)_(3))_(2)F.HgGa_(2)(SeO_(3))_(4) crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg_(2)Ga(Se_(O)_(3))_(2)F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg_(2)O_(2),its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa_(2)(SeO_(3))_(4).Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg_(2)Ga(Se_(O)_(3))_(2)F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.
基金support of the National Natural Science Foundation of China(NSFC,Nos.22371003,22101001,and 22471001)the Ministry of Education,Natural Science Foundation of Anhui Province(No.2408085Y006)+1 种基金the University Synergy Innovation Program of Anhui Province(No.GXXT-2020-053)the Scientific Research Program of Universities in Anhui Province(No.2022AH030009).
文摘Understanding the photoluminescence(PL)mechanism of metal nanoclusters from both molecular and supramolecular perspectives is crucial for developing highly emissive cluster-based nanomaterials.In this study,we synthesized two structurally similar Ag14 nanoclusters with different phosphine stabilizers,which demonstrated opposite PL behaviors in solution and crystalline states.The Ag14 nanocluster stabilized by P(Ph-OMe)_(3) ligands exhibited a higher PL intensity compared to the one stabilized by P(Ph-F)_(3) ligands,which was attributed to the stronger electron-donating ability of the P(Ph-OMe)_(3) ligand that improved ligand-to-metal charge transfer efficiency.In contrast,the P(Ph-F)_(3) stabilized Ag14 crystals displayed greater PL intensity than the Ag14 cluster crystal with a-OMe surface,which was due to stronger intermolecular interactions within the cluster lattice of the former that limited non-radiative energy loss and thus enhanced PL.Overall,this work aims to promote a comprehensive understanding of the fluorescence in cluster-based nanomaterials,which will be beneficial for their downstream applications.
基金Funded by Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022KJ100)National Natural Science Foundation of China(No.52172019)。
文摘Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.
基金supported by the Shaanxi Provincial High level Talent Introduction Project(5113220044)the Shaanxi Outstanding Youth Project(2023-JC-JQ-33)+8 种基金the Youth Science and Technology Talent Promotion Project of Jiangsu Association for Science and Technology(TJ-2022-088)the Project funded by China Postdoctoral Science Foundation(2023TQ0273,2023TQ0274,2023M742833)the NationalNatural Science Foundation of China(62304181)the Natural Science Basic Research Program of Shaanxi(2023-JC-QN-0726,2025JC-YBQN-469)the GuangdongBasic and Applied Basic Research Foundation(2022A1515110286,2024A1515012538)the Basic Research Programs of Taicang(TC2024JC04)the Suzhou Science and Technology Development Plan Innovation Leading Talent Project(ZXL2023183)the Fundamental Research Funds for the Central Universities(G2022KY05108,G2024KY0605,G2023KY0601)and the Aeronautical Science Foundation of China(2018ZD53047).
文摘Achieving simultaneous enhancement of crystallinity and optimal domain size remains a fundamental challenge in organic photovoltaics(OPVs),where conventional crystallization strategies often trigger excessive aggregation of small-molecule acceptors.This work pioneers a kinetic paradigm for resolving the crystallinity-domain size trade-off in organic photovoltaics through dual-additive-guided stepwise crystallization.By strategically pairing 1,2-dichlorobenzene(o-DCB,low binding energy to Y6)and 1-fluoronaphthalene(FN,high binding energy),we achieve temporally decoupled crystallization control:o-DCB first mediates donor-acceptor co-crystallization during film formation,constructing a metastable network,whereupon FN induces confined Y6 crystallization within this framework during thermal annealing,refining nanostructure without over-aggregation.Morphology studies reveal that this synergy enhances crystallinity of(100)diffraction peaks by 21%–10%versus single-additive controls(o-DCB/FN alone),while maintaining optimal domain size.These morphological advantages yield balanced carrier transport(μh/μe=1.23),near-unity exciton dissociation(98.53%),and a champion power conversion efficiency(PCE)of 18.08%for PM6:Y6,significantly surpassing single-additive devices(o-DCB:17.20%;FN:17.53%).Crucially,the dual-additive strategy demonstrates universal applicability across diverse active layer systems,achieving an outstanding PCE of 19.27%in PM6:L8-BO-based devices,thereby establishing a general framework for morphology control in high-efficiency OPVs.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2025A1515011362)the National Natural Science Foundation of China(52102304,52172238)Open Project of Shaanxi Laboratory of Aerospace Power(2021SXSYS-01-03).
文摘Pb-Sn mixed perovskite solar cells(PSCs)are crucial components for realizing efficient all-perovskite tandem devices.However,their efficiency and stability are severely limited by oxidative degradation(Sn^(4+)formation)and metallic defects(Sn^(0)/Pb^(0)).In addition,the rapid and uncontrolled Sn^(2+)nucleation kinetics result in nonuniform crystallization.Herein,we introduce a natural redox shuttle glutathione(GSH)in Pb-Sn mixed PSCs,achieving regenerable antioxidation and crystallization regulation simultaneously.The reversible redox reactions between GSH and glutathione disulfide(GSSG)enable the self-healing of Sn^(4+)and Sn^(0)/Pb^(0)impurities,creating a regenerable antioxidation protective shell at the perovskite interfaces.Meanwhile,the strong coordination between GSH and perovskite regulates the crystallization process,optimizing the nucleation and crystallization kinetics.Furthermore,the GSH incorporation creates a high-quality charge separation junction at the perovskite/hole transport layer,facilitating carrier separation and extraction.The optimized Pb-Sn PSCs exhibit impressive power conversion efficiencies(PCEs)of up to 23.71%.The champion all-perovskite tandem PSCs with GSH achieve a PCE of 28.49%and retain 90%of the initial PCE after 560 h of continuous illumination.This work establishes a new nature-inspired redox shuttling strategy and elucidates its working mechanism,advancing the development of efficient and stable all-perovskite tandem solar cells.
文摘A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.
基金supported by the National Natural Science Foundation of China(22361021,22261023)。
文摘Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.
基金by the Industry–Academia Cooperation Project No.113A00262(Te-Hua Fang).URLs to the sponsor websites are available at:https://www.nstc.gov.tw.
文摘The mechanical performance of exceedingly soft materials such as Ag is significantly influenced by various working conditions.Therefore,this study systematically investigates the effects of crack geometry,substrate crystal orientation,and indenter shape on crack propagation.The mechanical response of Ag is analyzed using the quasi-continuum(QC)method.A pre-crack with a predefined depth and angle was introduced to initiate fracture behavior.The results show that when the pre-crack height is 50 A,the crack propagates rapidly as the imprint depth increases from0 to 7 A,grows steadily up to 15 A,and then accelerates sharply between 15 and 20 A.For other pre-crack heights,crack propagation occurs at a relatively faster rate.Substrates with[100],[010],and[001]crystal orientations promote crack extension,while the onset of plastic deformation(referred to as the yield point in this study)and the fracture strength both increase with increasing pre-crack height.The yield point,fracture strength,and stress intensity factors are highly sensitive to the pre-crack height.When the pre-crack angle is 90○,the fracture strength reaches its maximum of 0.2%higher than that of the uncracked sample-whereas at 0○,it reaches its minimum,still 53.8%higher than that of the uncracked sample.The sample model is conducted using AutoCAD software.The optimized quasicontinuum(QC)method is used to investigate the effects of different crack geometries,substrate crystal orientations,and indenter shapes on the crack extension of Ag material.Baskes and Dow(FBD)potential is borrowed to describe the interaction forces between Ag-Ag,Ni-Ag,and Ni-Ni.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
