Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electron...Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electronic structure involving spin-related charge transfer and orbital interactions has been largely underexplored in sulfur electrocatalysts.Herein,selenium-deficient bimetallic selenides embedded in a coaxial carbon layer(CoSe_(2-x)/ZnSe)were meticulously fabricated as electrocatalysts,aiming to modulate the electron spin state of Co catalytic sites to enhance the bidirectional lithium polysulfides(LiPSs)conversion kinetics and suppress the LiPSs shuttling effect.Density functional theory(DFT)calculations and experimental results indicate that the selenium vacancies at the CoSe_(2-x)/ZnSe heterointerfaces weaken the ligand fields and drive the Co 3d orbital electronic structure transition from low-spin to high-spin states.Such tailored spin state configuration generates more unpaired electrons and upshifts the dband center,thus accelerating the charge transfer and strengthening the orbital interactions between LiPSs and Co catalytic sites.As a consequence,the assembled Li-S batteries with CoSe_(2-x)/ZnSe electrocatalysts exhibit an ultralow average decay rate of 0.028%per cycle at 1 C over 1000 cycles.This work presents a novel strategy for manipulating ligand fields to realize electron spin state modulation in sulfur electrocatalysts.展开更多
To improve the theoretical prediction accuracy of static mechanical quantities in MEMS cantilever beams for microwave power detection chips,a distributed static model is proposed based on the deflection equation.An an...To improve the theoretical prediction accuracy of static mechanical quantities in MEMS cantilever beams for microwave power detection chips,a distributed static model is proposed based on the deflection equation.An analytical frame-work is established through the precise characterization of cantilever beam bending.The framework can accurately extract key electromechanical parameters,and the correlation between these parameters and geometric changes is systematically studied.Results show that the pull-in voltage increases with the gap but decreases with the length.The predicted pull-in voltage indi-cates a relative error of only 6.5%between the distributed static model and the simulation,which is significantly lower than that of the other two models.The overload power and sensitivity are also analyzed to facilitate performance trade-offs in chip design.The measured return loss varies between-66.46 and-10.56 dB over the 8-12 GHz frequency band,exhibiting a charac-teristic V-shaped trend.Moreover,the measured sensitivity of 66.5 fF/W closely matches the theoretical value of 69.3 fF/W,show-ing a relative error of 5.6%.These findings confirm that the distributed model outperforms the other two in terms of both accu-racy and physical realism,thereby providing important reference for the design of microwave power detection chips.展开更多
The promising combustion and emission properties of polyoxymethylene dimethyl ethers(PODEn)are of significant interest.However,the synthesis of PODEn products with desired chain lengths is still a problem facing synth...The promising combustion and emission properties of polyoxymethylene dimethyl ethers(PODEn)are of significant interest.However,the synthesis of PODEn products with desired chain lengths is still a problem facing synthetic PODEn.Herein,a series of unique IL@SBA16Cx solid catalysts are prepared by encapsulation of ionic liquids(ILs)within the nanocage of SBA16 through a silylation method.The structure of the encapsulated catalyst was characterized by UVvis spectra,Fourier transform infrared(FTIR),N2 adsorptiondesorption isotherms,Powder Xray diffraction(XRD),Transmission electron microscopy(TEM)and Elemental analysis.The encapsulated catalysts show similar catalytic activity to the homogeneous counterparts and display higher selectivity to the targeted PODE35 products than their homogeneous counterparts in the synthesis of PODEn from methanol(MeOH)and trioxymethylene(TOM).The encapsulated catalysts exhibit a superior PODE35 selectivity and could be the promising catalysts for PODEn synthetic reaction.展开更多
Directed peptides C-terminal modification enabled by the engineered biomolecular catalyst-peptide amidase 12 B has been achieved via computational protein engineering. The engineered enzyme exhibits great promising po...Directed peptides C-terminal modification enabled by the engineered biomolecular catalyst-peptide amidase 12 B has been achieved via computational protein engineering. The engineered enzyme exhibits great promising potential in the C-terminal modification of opioid peptides using prop-2-yn-1-amine(PYA) or prop-2-en-l-amine(PEA) as the nucleophile. A variety of opioid peptides could be readily functionalized at the C-terminal chain in high yield in a mild and selective manner. Notably, modified opioid peptides bearing alkynyl moiety could be further functionalized through well-established click reaction.展开更多
Bimetallic CuCo catalysts with different Cu to Co ratios on N-doped porous carbon materials(N-C)were achieved using impregnation method and applied in the hydrogenation of furfural(FAL)to furfuryl alcohol(FOL).The hig...Bimetallic CuCo catalysts with different Cu to Co ratios on N-doped porous carbon materials(N-C)were achieved using impregnation method and applied in the hydrogenation of furfural(FAL)to furfuryl alcohol(FOL).The high hydrogenation activity of FAL over Cu_(1)Co_(1)/N-C was originated from the synergistic interactions of Cu and Co species,where Co^(0)and Cu^(0)simultaneously adsorb and activate H_(2),and Cu^(+) served as Lewis acid sites to activate C]O.Meanwhile,electrons transfer from Cu to Co promoted the formation of Cu^(+).In situ Fourier transform infrared spectroscopy analysis indicated that Cu_(1)Co_(1)/N-C adsorbed FAL with a tilted η^(1)-(O)configuration.The superior Cu_(1)Co_(1)/N-C showed excellent adsorbed ability towards H_(2) and FAL,but weak adsorption for FOL.Therefore,Cu_(1)Co_(1)/N-C possessed 93.1%FAL conversion and 99.0% FOL selectivity after 5 h reaction,which also exhibited satisfactory reusability in FAL hydrogenation for five cycles.展开更多
The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effecti...The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effectively removes work hardening in both the Cu matrix and Fe fibers,restoring their plastic deformation capacity and preserving fiber continuity during subsequent redrawing.The process also refines the Fe phase,leading to a more uniform size distribution and straighter,better-aligned Cu/Fe phase interfaces,thereby enhancing the comprehensive properties of the alloy.The magnitude of drawing strain during intermediate annealing plays a critical role in balancing the mechanical strength and electrical conductivity of redrawn wires.A lower initial drawing strain requires greater redrawing strain,leading to excessive hardening of the Fe fibers,which negatively impacts the electrical conductivity and tensile plasticity.Conversely,a higher initial drawing strain can result in insufficient work hardening during the redrawing deformation process,yielding minimal strength improvements.Among the tested alloys,H/3.5 wires show a slight reduction in strength and hardness compared to W and H/4.5 wires but exhibit a significant increase in tensile elongation and electrical conductivity.The tensile strength was 755 MPa,and the electrical conductivity was 47%international-annealed copper standard(IACS).The optimal performance is attributed to the formation of a high-density,ultrafine Fe fiber structure-aligned parallel to the drawing direction,which is achieved through a suitable combination of the drawing process and intermediate annealing.展开更多
Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst fo...Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst for methylcyclohexane dehydrogenation at a low temperature.The homogeneous incorporation of Ni atoms into the mesoporous framework of alumina and the formation of surface Ni-O-Al bonds benefit the generation of surface coordinated unsaturated aluminum species,which play a crucial role in highly homogenously dispersing Pt active sites in a form of single-atom clusters.Consequently,the resultant catalyst Pt/MNA displayed significantly improved catalytic performance.For example,at 300℃,catalyst Pt/MNA demonstrated a notable catalytic activity with a maximum hydrogen evolution rate of 3057 mmol/gPt/min,even after a long-time reaction up to 100 h or regeneration,which is inspiringly superior to the state-of-the-art supported Ptbased catalysts.The obviously boosted catalytic reactivity of catalyst Pt/MNA can be attributed to the excellent structural and textural properties,the remarkably raised Pt utilization efficiency,and the synergic catalytic effect derived from the interface electron transfer from support MNA to metallic Pt active sites.Our results provided a rational design strategy for the development of promising Pt-based catalyst for methylcyclohexane dehydrogenation,which is vital in the utilization of methylcyclohexane-toluene system for hydrogen storage.展开更多
The mill products like sheet always have one or more severe textures inevitably,and its effect on mechanical properties is not a negligible issue.The orientation dependent tensile-creep behavior induced by rolling tex...The mill products like sheet always have one or more severe textures inevitably,and its effect on mechanical properties is not a negligible issue.The orientation dependent tensile-creep behavior induced by rolling texture of Ti65 titanium alloy sheet has been systematically investigated at 650℃.There are some anisotropic characteristics between TD and RD of Ti65 sheet.The UTS and TYS of TD are higher than RD at 650℃.Besides,the creep endurance time of TD(172.6–174.5 h)is about three times longer than RD(55.6–65.1 h)at 650℃and 240 MPa.Moreover,the grains are inclined to form Texture III■after creep along with TD,but to form Texture I■after creep along with RD.Finally,the crack initiation site is different during creep in TD and RD.The reason for anisotropic properties of tensile and creep has been summarized in two aspects:(i)the change of the SFs(Schmid factors)value between TD and RD;(ii)the difference of creep mechanism between TD(grain boundary sliding)and RD(dislocation slip).Anisotropy of Ti65 sheet should be fully considered to increase structural efficiency in the engineering design and application.展开更多
Zirconium-based MOFs of the UiO family have attracted considerable attention due to their high thermal,chemical and mechanical stability. With the aim of further exploring the applications of zirconium-based UiO-66 in...Zirconium-based MOFs of the UiO family have attracted considerable attention due to their high thermal,chemical and mechanical stability. With the aim of further exploring the applications of zirconium-based UiO-66 in acid-catalyzed reactions and elucidating the effects of the defects in UiO-66 materials on their catalytic performances, in this work, a series of zirconium-containing UiO-66 samples were synthesized by varying the synthesis temperatures and BDC/Zr(terephthalic acid/ZrCl) ratios in the synthesis system.The synthesized UiO-66 samples were characterized by X-ray diffraction(XRD), Nadsorption-desorption,scanning electron microscopy(SEM), thermogravimetrical analysis(TGA), temperature-programmed desorption of NH(NH-TPD). Their catalytic performances were investigated in transesterification of tributyrin and soybean oil with methanol. The results showed that UiO-66 samples with different amounts of defects could be successfully prepared by varying the synthesis temperatures and/or the BDC/Zr ratios used in the synthesis system. The catalytic activities of the UiO-66 materials greatly depended on their linker defects and enhanced with the increase of the defect amount. The UiO-66 was an efficient catalyst for transesterification of tributyrin and soybean oil with methanol under mild reaction conditions and its catalytic activity was comparable to other solid acid catalysts reported in the literatures. The UiO-66 catalyst was relatively stable and could be reused.展开更多
Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. I...Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al;O;catalysts were characterized by XRD, N;adsorption–desorption, SEM-EDS, and H;-TPR.The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al;O;catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction（STD）. The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al;O;with 15% copper molar ratio achieve 52.9% and 66.1%,respectively. Moreover, the mesoporous Cu/Al;O;catalysts show excellent stability in STD reaction.展开更多
Head and neck squamous cell carcinoma (HNSCC) is a prevalent and lethal solid tumor with a high mortality rate. Conventional cancertreatments, including surgery, radiotherapy, and chemotherapy, primarily target cancer...Head and neck squamous cell carcinoma (HNSCC) is a prevalent and lethal solid tumor with a high mortality rate. Conventional cancertreatments, including surgery, radiotherapy, and chemotherapy, primarily target cancer cell eradication. However, uncontrolled proliferation and metabolic activities of these cells result in abnormalities in nutrient levels, hypoxia, and immunosuppression within the tumor microenvironment (TME). These factors constrain the efficacy of traditional treatments by promoting drug resistance, recurrence, and metastasis. Nanomaterials (NMs), such as nanozymes, can exhibit enzymatic activity similar to that of natural enzymes and offer a promising avenuefor the direct modification of the TME through catalytic oxidation-reduction processes. Moreover, they can serve as sensitizers or drug deliverycarriers, enhancing the efficacy of traditional treatment methods. Recently, NMs have garnered significant attention from oncologists. Thisreview begins with an overview of the composition and unique characteristics of the TME. Subsequently, we comprehensively exploredthe application of NMs in the treatment of HNSCC. Finally, we discuss the potential prospects and challenges associated with usingNMs in biomedical research.展开更多
In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel g...In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel graphbased semantic region descriptions, which are estimated in a dynamically fashion. We propose a two-level update algorithm, namely, Symbols update level and Regions update level. The algorithm firstly adopts particle filter to update weights of the symbols, and then use the Viterbi algorithm to estimate the region the robot stays in based on those weights, optimally. Experimental results demonstrate that our proposed approach can solve problems of the long-term operation and kidnapped robot problem.展开更多
Feature matching has been frequently applied in computer vision and pattern recognition.In this paper,the authors propose a fast feature matching algorithm for vector-based feature.Their algorithm searches r-nearest n...Feature matching has been frequently applied in computer vision and pattern recognition.In this paper,the authors propose a fast feature matching algorithm for vector-based feature.Their algorithm searches r-nearest neighborhood clusters for the query point after a k-means clustering,which shows higher efficiency in three aspects.First,it does not reformat the data into a complex tree,so it shortens the construction time twice.Second,their algorithm adopts the r-nearest searching strategy to increase the probability to contain the exact nearest neighbor(NN)and take this NN as the global one,which can accelerate the searching speed by 170 times.Third,they set up a matching rule with a variant distance threshold to eliminate wrong matches.Their algorithm has been tested on large SIFT databases with different scales and compared with two widely applied algorithms,priority search km-tree and random kd-tree.The results show that their algorithm outperforms both algorithms in terms of speed up over linear search,and consumes less time than km-tree.Finally,they carry out the CFI test based on ISKLRS database using their algorithm.The test results show that their algorithm can greatly improve the recognition speed without affecting the recognition rate.展开更多
Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructu...Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructure and mechanical properties of Al/Cu FSB joints were investigated along with the temperature and resistance of the friction tool.The oscillation of forward resistance and lateral force was related to the flow of the plastic metal and contributed to obtain a good appearance during the welding process.From the appearance of the welded joints,it was obvious that the phase difference between the forward resistance and lateral force had a significant influence on the joint characteristics.Obvious scale-like ripples appeared on the weld area when a sharp angle in the phase difference curve existed.Additionally,with a lower axial force and oscillation assistance,a satisfactory joint could be obtained.The results of the shear strength of the brazed joint showed that the shoulder with a 12 mm diameter yielded the highest shear strength.Meanwhile,the zinc foil in the middle melted completely and formed finely dispersed CuZn5 Al–Zn eutectic structures at the Al–Cu interface.展开更多
Random optical systems have been widely investigated due to their abundant physical effects,including numerous degrees of freedom and equilibrium states.Whereas the boundary perturbation can disturb the dynamical beha...Random optical systems have been widely investigated due to their abundant physical effects,including numerous degrees of freedom and equilibrium states.Whereas the boundary perturbation can disturb the dynamical behavior of the equilibrium states and lead to a series of unexplored evolution,here we unveil the equilibrium transition induced by boundary perturbation in random fiber lasers through introducing a laser-feedback process.In this typical random optical system,the predominant role of random scattering can be manipulated by a laser-feedback process that serves as boundary perturbation,causing the transition of the equilibrium state and output properties of the laser.On this basis,the photon lifetime can also be reduced,presenting huge potential in highly sensitive non-contact sensing with a detectable minimum feedback power of 12.08 f W and a detection distance of130 km.Our work provides a new perspective in deepening the understanding of intrinsic mechanisms in random systems and broadens the underlying applications,including modal manipulation and high sensitivity measurement.展开更多
The aim is to explore the predictive value of salivary bacteria for the presence of esophageal squamous cell carcinoma (ESCC). Saliva samples were obtained from 178 patients with ESCC and 101 healthy controls, and all...The aim is to explore the predictive value of salivary bacteria for the presence of esophageal squamous cell carcinoma (ESCC). Saliva samples were obtained from 178 patients with ESCC and 101 healthy controls, and allocated to screening and verification cohorts, respectively. In the screening phase, after saliva DNA was extracted, 16S rRNA V4 regions of salivary bacteria were amplified by polymerase chain reaction (PCR) with high-throughput sequencing. Highly expressed target bacteria were screened by Operational Taxonomic Units clustering, species annotation and microbial diversity assessment. In the verification phase, the expression levels of target bacteria identified in the screening phase were verified by absolute quantitative PCR (Q-PCR). Receiver operating characteristic (ROC) curves were plotted to investigate the predictive value of target salivary bacteria. LEfSe analysis revealed higher proportions of Fusobacterium, Streptococcus and Porphyromonas, and Q-PCR assay showed significantly higher numbers of Streptococcus salivarius, Fusobacterium nucleatum and Porphyromonas gingivalis in patients with ESCC, when compared with healthy controls (all P < 0.05). The areas under the ROC curves for Streptococcus salivarius, Fusobacterium nucleatum, Porphyromonas gingivalis and the combination of the three bacteria for predicting patients with ESCC were 69%, 56.5%, 61.8% and 76.4%, respectively. The sensitivities corresponding to cutoff value were 69.3%, 22.7%, 35.2% and 86.4%, respectively, and the matched specificity were 78.4%, 96.1%, 90.2% and 58.8%, respectively. These highly expressed Streptococcus salivarius, Fusobacterium nucleatum and Porphyromonas gingivalis in the saliva, alone or in combination, indicate their predictive value for ESCC.展开更多
Genomic studies of cancer cell alterations,such as mutations,copy number variations(CNVs),and translocations,greatly promote our understanding of the genesis and development of cancers.However,the 3D genome architectu...Genomic studies of cancer cell alterations,such as mutations,copy number variations(CNVs),and translocations,greatly promote our understanding of the genesis and development of cancers.However,the 3D genome architecture of cancers remains less studied due to the complexity of cancer genomes and technical difficulties.To explore the 3D genome structure in clinical lung cancer,we performed Hi-C experiments using paired normal and tumor cells harvested from patients with lung cancer,combining with RNA sequenceing analysis.We demonstrated the feasibility of studying 3D genome of clinical lung cancer samples with a small number of cells(1×10^(4)),compared the genome architecture between clinical samples and cell lines of lung cancer,and identified conserved and changed spatial chromatin structures between normal and cancer samples.We also showed that Hi-C data can be used to infer CNVs and point mutations in cancer.By integrating those different types of cancer alterations,we showed significant associations between CNVs,3D genome,and gene expression.We propose that 3D genome mediates the effects of cancer genomic alterations on gene expression through altering regulatory chromatin structures.Our study highlights the importance of analyzing 3D genomes of clinical cancer samples in addition to cancer cell lines and provides an integrative genomic analysis pipeline for future larger-scale studies in lung cancer and other cancers.展开更多
The oligomerization of light olefins is an alternative for generating clean liquid fuels.In this study,the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring(10 ...The oligomerization of light olefins is an alternative for generating clean liquid fuels.In this study,the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring(10 MR)was discussed for 1-hexene oligomerization.MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization.The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite.The MCM-22 zeolite was characterized in detail by NMR,Py-FTIR,and TG analyses.The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated.Structure-activity relationships were established through the kinetic study.Although the density of strong acid sites was essential for the oligomerization of 1-hexene,the presence of low pressure was also necessary for the formation of dimers.Thus,MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.展开更多
Selective hydrogenation of Levulinic acid(LA)toγ-Valerolactone(GVL)is an important reaction to produce high value-added chemicals and fuels but remains a big challenge.Herein we reported a Ru/zeolite catalyst with Mn...Selective hydrogenation of Levulinic acid(LA)toγ-Valerolactone(GVL)is an important reaction to produce high value-added chemicals and fuels but remains a big challenge.Herein we reported a Ru/zeolite catalyst with Mn promotion,which exhibited excellent catalytic performance(yield:98%)towards LA to GVL.The intrinsic activity(TOF)also increased obviously with the Mn addition.The particle size of Ru gradually decreased with the increase of Mn loading and a strong interaction between Ru and support was observed for the Ru-Mn/MCM-49 catalyst.The addition of Mn not only offered a good dispersion of Ru species on MCM-49,but also increased the L/B ratio of the catalyst,thereby contributing to the high GVL selectivity.High dispersed Ru sites were the intrinsic active sites of the catalyst verified by the in-situ experimental studies.The dissociation of the reactants was significantly enhanced,resulting in higher catalytic activity.展开更多
基金supported by the National Natural Science Foundation of China(No.52172214,52472220)。
文摘Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electronic structure involving spin-related charge transfer and orbital interactions has been largely underexplored in sulfur electrocatalysts.Herein,selenium-deficient bimetallic selenides embedded in a coaxial carbon layer(CoSe_(2-x)/ZnSe)were meticulously fabricated as electrocatalysts,aiming to modulate the electron spin state of Co catalytic sites to enhance the bidirectional lithium polysulfides(LiPSs)conversion kinetics and suppress the LiPSs shuttling effect.Density functional theory(DFT)calculations and experimental results indicate that the selenium vacancies at the CoSe_(2-x)/ZnSe heterointerfaces weaken the ligand fields and drive the Co 3d orbital electronic structure transition from low-spin to high-spin states.Such tailored spin state configuration generates more unpaired electrons and upshifts the dband center,thus accelerating the charge transfer and strengthening the orbital interactions between LiPSs and Co catalytic sites.As a consequence,the assembled Li-S batteries with CoSe_(2-x)/ZnSe electrocatalysts exhibit an ultralow average decay rate of 0.028%per cycle at 1 C over 1000 cycles.This work presents a novel strategy for manipulating ligand fields to realize electron spin state modulation in sulfur electrocatalysts.
基金supported by the National Natural Science Foundation of China(61904089)the Province Natural Science Foundation of Jiangsu(BK20190731).
文摘To improve the theoretical prediction accuracy of static mechanical quantities in MEMS cantilever beams for microwave power detection chips,a distributed static model is proposed based on the deflection equation.An analytical frame-work is established through the precise characterization of cantilever beam bending.The framework can accurately extract key electromechanical parameters,and the correlation between these parameters and geometric changes is systematically studied.Results show that the pull-in voltage increases with the gap but decreases with the length.The predicted pull-in voltage indi-cates a relative error of only 6.5%between the distributed static model and the simulation,which is significantly lower than that of the other two models.The overload power and sensitivity are also analyzed to facilitate performance trade-offs in chip design.The measured return loss varies between-66.46 and-10.56 dB over the 8-12 GHz frequency band,exhibiting a charac-teristic V-shaped trend.Moreover,the measured sensitivity of 66.5 fF/W closely matches the theoretical value of 69.3 fF/W,show-ing a relative error of 5.6%.These findings confirm that the distributed model outperforms the other two in terms of both accu-racy and physical realism,thereby providing important reference for the design of microwave power detection chips.
基金The authors greatly acknowledge Prof.Tim Storr from Simon Fraser University for his help in English writing and improving of this paper.The work was supported by the Natural Science Foundation of Shanxi Province(201801D121062)the Shanxi Scholarship Council of China(2017-037)the Foundation of Taiyuan University of Technology(2016MS03).
文摘The promising combustion and emission properties of polyoxymethylene dimethyl ethers(PODEn)are of significant interest.However,the synthesis of PODEn products with desired chain lengths is still a problem facing synthetic PODEn.Herein,a series of unique IL@SBA16Cx solid catalysts are prepared by encapsulation of ionic liquids(ILs)within the nanocage of SBA16 through a silylation method.The structure of the encapsulated catalyst was characterized by UVvis spectra,Fourier transform infrared(FTIR),N2 adsorptiondesorption isotherms,Powder Xray diffraction(XRD),Transmission electron microscopy(TEM)and Elemental analysis.The encapsulated catalysts show similar catalytic activity to the homogeneous counterparts and display higher selectivity to the targeted PODE35 products than their homogeneous counterparts in the synthesis of PODEn from methanol(MeOH)and trioxymethylene(TOM).The encapsulated catalysts exhibit a superior PODE35 selectivity and could be the promising catalysts for PODEn synthetic reaction.
基金supported by the National Natural Science Foundation of China(No.31601412)the 100 Talent Program grant and Biological Resources Service Network Initiative(No.ZSYS-012)grant from the Chinese Academy of Sciences(No.SKT1604)
文摘Directed peptides C-terminal modification enabled by the engineered biomolecular catalyst-peptide amidase 12 B has been achieved via computational protein engineering. The engineered enzyme exhibits great promising potential in the C-terminal modification of opioid peptides using prop-2-yn-1-amine(PYA) or prop-2-en-l-amine(PEA) as the nucleophile. A variety of opioid peptides could be readily functionalized at the C-terminal chain in high yield in a mild and selective manner. Notably, modified opioid peptides bearing alkynyl moiety could be further functionalized through well-established click reaction.
基金the National Natural Science Foundation of China (22108189, 22278286)Science Foundation for Distinguished Young Scholar of Shanxi Province(202303021223001)SINOPEC 122027
文摘Bimetallic CuCo catalysts with different Cu to Co ratios on N-doped porous carbon materials(N-C)were achieved using impregnation method and applied in the hydrogenation of furfural(FAL)to furfuryl alcohol(FOL).The high hydrogenation activity of FAL over Cu_(1)Co_(1)/N-C was originated from the synergistic interactions of Cu and Co species,where Co^(0)and Cu^(0)simultaneously adsorb and activate H_(2),and Cu^(+) served as Lewis acid sites to activate C]O.Meanwhile,electrons transfer from Cu to Co promoted the formation of Cu^(+).In situ Fourier transform infrared spectroscopy analysis indicated that Cu_(1)Co_(1)/N-C adsorbed FAL with a tilted η^(1)-(O)configuration.The superior Cu_(1)Co_(1)/N-C showed excellent adsorbed ability towards H_(2) and FAL,but weak adsorption for FOL.Therefore,Cu_(1)Co_(1)/N-C possessed 93.1%FAL conversion and 99.0% FOL selectivity after 5 h reaction,which also exhibited satisfactory reusability in FAL hydrogenation for five cycles.
基金support provided by the National Natural Science Foundation of China(Nos.52405364,and 52171110)the Jiangsu Funding Program for Excellent Postdoctoral Talent.W.Huo acknowledges the support from the European Union Horizon 2020 Research and Innovation Program(No.857470)+1 种基金from the European Regional Development Fund via the Foundation for Polish Science International Research Agenda PLUS Program(No.MAB PLUS/2018/8)The publication was partly created within the framework of the project of the Minister of Science and Higher Education"Support for the activities of Centers of Excellence established in Poland under Horizon 2020"(No.MEiN/2023/DIR/3795).
文摘The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effectively removes work hardening in both the Cu matrix and Fe fibers,restoring their plastic deformation capacity and preserving fiber continuity during subsequent redrawing.The process also refines the Fe phase,leading to a more uniform size distribution and straighter,better-aligned Cu/Fe phase interfaces,thereby enhancing the comprehensive properties of the alloy.The magnitude of drawing strain during intermediate annealing plays a critical role in balancing the mechanical strength and electrical conductivity of redrawn wires.A lower initial drawing strain requires greater redrawing strain,leading to excessive hardening of the Fe fibers,which negatively impacts the electrical conductivity and tensile plasticity.Conversely,a higher initial drawing strain can result in insufficient work hardening during the redrawing deformation process,yielding minimal strength improvements.Among the tested alloys,H/3.5 wires show a slight reduction in strength and hardness compared to W and H/4.5 wires but exhibit a significant increase in tensile elongation and electrical conductivity.The tensile strength was 755 MPa,and the electrical conductivity was 47%international-annealed copper standard(IACS).The optimal performance is attributed to the formation of a high-density,ultrafine Fe fiber structure-aligned parallel to the drawing direction,which is achieved through a suitable combination of the drawing process and intermediate annealing.
基金supported by the National Natural Science Foundation of China(21975174 and 22378286)the Natural Science Foundation of Shanxi Province,China(202403021221036)+1 种基金the Funds for Central Government to Guide Local Science and Technology Development(YDZJSX2021A014)the Research Project Supported by Shanxi Scholarship Council of China(2024-036).
文摘Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst for methylcyclohexane dehydrogenation at a low temperature.The homogeneous incorporation of Ni atoms into the mesoporous framework of alumina and the formation of surface Ni-O-Al bonds benefit the generation of surface coordinated unsaturated aluminum species,which play a crucial role in highly homogenously dispersing Pt active sites in a form of single-atom clusters.Consequently,the resultant catalyst Pt/MNA displayed significantly improved catalytic performance.For example,at 300℃,catalyst Pt/MNA demonstrated a notable catalytic activity with a maximum hydrogen evolution rate of 3057 mmol/gPt/min,even after a long-time reaction up to 100 h or regeneration,which is inspiringly superior to the state-of-the-art supported Ptbased catalysts.The obviously boosted catalytic reactivity of catalyst Pt/MNA can be attributed to the excellent structural and textural properties,the remarkably raised Pt utilization efficiency,and the synergic catalytic effect derived from the interface electron transfer from support MNA to metallic Pt active sites.Our results provided a rational design strategy for the development of promising Pt-based catalyst for methylcyclohexane dehydrogenation,which is vital in the utilization of methylcyclohexane-toluene system for hydrogen storage.
基金the National Natural Science Foundation of China(No.51801156)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2019JM-584).
文摘The mill products like sheet always have one or more severe textures inevitably,and its effect on mechanical properties is not a negligible issue.The orientation dependent tensile-creep behavior induced by rolling texture of Ti65 titanium alloy sheet has been systematically investigated at 650℃.There are some anisotropic characteristics between TD and RD of Ti65 sheet.The UTS and TYS of TD are higher than RD at 650℃.Besides,the creep endurance time of TD(172.6–174.5 h)is about three times longer than RD(55.6–65.1 h)at 650℃and 240 MPa.Moreover,the grains are inclined to form Texture III■after creep along with TD,but to form Texture I■after creep along with RD.Finally,the crack initiation site is different during creep in TD and RD.The reason for anisotropic properties of tensile and creep has been summarized in two aspects:(i)the change of the SFs(Schmid factors)value between TD and RD;(ii)the difference of creep mechanism between TD(grain boundary sliding)and RD(dislocation slip).Anisotropy of Ti65 sheet should be fully considered to increase structural efficiency in the engineering design and application.
基金supported by the National Science Foundation of China (Nos. 20971095 and 21576177)Research Project Supported by Shanxi Scholarship Council of China (2013-047)
文摘Zirconium-based MOFs of the UiO family have attracted considerable attention due to their high thermal,chemical and mechanical stability. With the aim of further exploring the applications of zirconium-based UiO-66 in acid-catalyzed reactions and elucidating the effects of the defects in UiO-66 materials on their catalytic performances, in this work, a series of zirconium-containing UiO-66 samples were synthesized by varying the synthesis temperatures and BDC/Zr(terephthalic acid/ZrCl) ratios in the synthesis system.The synthesized UiO-66 samples were characterized by X-ray diffraction(XRD), Nadsorption-desorption,scanning electron microscopy(SEM), thermogravimetrical analysis(TGA), temperature-programmed desorption of NH(NH-TPD). Their catalytic performances were investigated in transesterification of tributyrin and soybean oil with methanol. The results showed that UiO-66 samples with different amounts of defects could be successfully prepared by varying the synthesis temperatures and/or the BDC/Zr ratios used in the synthesis system. The catalytic activities of the UiO-66 materials greatly depended on their linker defects and enhanced with the increase of the defect amount. The UiO-66 was an efficient catalyst for transesterification of tributyrin and soybean oil with methanol under mild reaction conditions and its catalytic activity was comparable to other solid acid catalysts reported in the literatures. The UiO-66 catalyst was relatively stable and could be reused.
基金supported by the National Natural Science Foundation of China(No.51,451,002,No.21,371,129)Shanxi Province Science Foundation for Youths(2,013,021,008-3)the joint funds of the National Natural Science Foundation of China–China Petroleum and Chemical Corporation(the state key program grant No.U1463209)
文摘Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al;O;catalysts were characterized by XRD, N;adsorption–desorption, SEM-EDS, and H;-TPR.The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al;O;catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction（STD）. The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al;O;with 15% copper molar ratio achieve 52.9% and 66.1%,respectively. Moreover, the mesoporous Cu/Al;O;catalysts show excellent stability in STD reaction.
基金supported by medical science research joint construction project of Henan(71188)Henan Provincial Department of Education under grant no.21B320008.
文摘Head and neck squamous cell carcinoma (HNSCC) is a prevalent and lethal solid tumor with a high mortality rate. Conventional cancertreatments, including surgery, radiotherapy, and chemotherapy, primarily target cancer cell eradication. However, uncontrolled proliferation and metabolic activities of these cells result in abnormalities in nutrient levels, hypoxia, and immunosuppression within the tumor microenvironment (TME). These factors constrain the efficacy of traditional treatments by promoting drug resistance, recurrence, and metastasis. Nanomaterials (NMs), such as nanozymes, can exhibit enzymatic activity similar to that of natural enzymes and offer a promising avenuefor the direct modification of the TME through catalytic oxidation-reduction processes. Moreover, they can serve as sensitizers or drug deliverycarriers, enhancing the efficacy of traditional treatment methods. Recently, NMs have garnered significant attention from oncologists. Thisreview begins with an overview of the composition and unique characteristics of the TME. Subsequently, we comprehensively exploredthe application of NMs in the treatment of HNSCC. Finally, we discuss the potential prospects and challenges associated with usingNMs in biomedical research.
基金supported by the National Natural Science Foundation of China (61305103 and 61473103)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (51521003 )+1 种基金the Natural Science Foundation of Heilongjiang Province, China (QC2014C072 and F2015010)SelfPlanned Task (SKLRS201609B and SKLRS201411B) of State Key Laboratory of Robotics and System (HIT)
文摘In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel graphbased semantic region descriptions, which are estimated in a dynamically fashion. We propose a two-level update algorithm, namely, Symbols update level and Regions update level. The algorithm firstly adopts particle filter to update weights of the symbols, and then use the Viterbi algorithm to estimate the region the robot stays in based on those weights, optimally. Experimental results demonstrate that our proposed approach can solve problems of the long-term operation and kidnapped robot problem.
文摘Feature matching has been frequently applied in computer vision and pattern recognition.In this paper,the authors propose a fast feature matching algorithm for vector-based feature.Their algorithm searches r-nearest neighborhood clusters for the query point after a k-means clustering,which shows higher efficiency in three aspects.First,it does not reformat the data into a complex tree,so it shortens the construction time twice.Second,their algorithm adopts the r-nearest searching strategy to increase the probability to contain the exact nearest neighbor(NN)and take this NN as the global one,which can accelerate the searching speed by 170 times.Third,they set up a matching rule with a variant distance threshold to eliminate wrong matches.Their algorithm has been tested on large SIFT databases with different scales and compared with two widely applied algorithms,priority search km-tree and random kd-tree.The results show that their algorithm outperforms both algorithms in terms of speed up over linear search,and consumes less time than km-tree.Finally,they carry out the CFI test based on ISKLRS database using their algorithm.The test results show that their algorithm can greatly improve the recognition speed without affecting the recognition rate.
文摘Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructure and mechanical properties of Al/Cu FSB joints were investigated along with the temperature and resistance of the friction tool.The oscillation of forward resistance and lateral force was related to the flow of the plastic metal and contributed to obtain a good appearance during the welding process.From the appearance of the welded joints,it was obvious that the phase difference between the forward resistance and lateral force had a significant influence on the joint characteristics.Obvious scale-like ripples appeared on the weld area when a sharp angle in the phase difference curve existed.Additionally,with a lower axial force and oscillation assistance,a satisfactory joint could be obtained.The results of the shear strength of the brazed joint showed that the shoulder with a 12 mm diameter yielded the highest shear strength.Meanwhile,the zinc foil in the middle melted completely and formed finely dispersed CuZn5 Al–Zn eutectic structures at the Al–Cu interface.
基金National Natural Science Foundation of China(62275001,62205001,62405001,62105001)Natural Science Foundation of Anhui Province(2408085QF206)。
文摘Random optical systems have been widely investigated due to their abundant physical effects,including numerous degrees of freedom and equilibrium states.Whereas the boundary perturbation can disturb the dynamical behavior of the equilibrium states and lead to a series of unexplored evolution,here we unveil the equilibrium transition induced by boundary perturbation in random fiber lasers through introducing a laser-feedback process.In this typical random optical system,the predominant role of random scattering can be manipulated by a laser-feedback process that serves as boundary perturbation,causing the transition of the equilibrium state and output properties of the laser.On this basis,the photon lifetime can also be reduced,presenting huge potential in highly sensitive non-contact sensing with a detectable minimum feedback power of 12.08 f W and a detection distance of130 km.Our work provides a new perspective in deepening the understanding of intrinsic mechanisms in random systems and broadens the underlying applications,including modal manipulation and high sensitivity measurement.
基金This study was supported by the Scientific Research Project of Guangzhou, Guangdong Province, China (No. 20184010458).
文摘The aim is to explore the predictive value of salivary bacteria for the presence of esophageal squamous cell carcinoma (ESCC). Saliva samples were obtained from 178 patients with ESCC and 101 healthy controls, and allocated to screening and verification cohorts, respectively. In the screening phase, after saliva DNA was extracted, 16S rRNA V4 regions of salivary bacteria were amplified by polymerase chain reaction (PCR) with high-throughput sequencing. Highly expressed target bacteria were screened by Operational Taxonomic Units clustering, species annotation and microbial diversity assessment. In the verification phase, the expression levels of target bacteria identified in the screening phase were verified by absolute quantitative PCR (Q-PCR). Receiver operating characteristic (ROC) curves were plotted to investigate the predictive value of target salivary bacteria. LEfSe analysis revealed higher proportions of Fusobacterium, Streptococcus and Porphyromonas, and Q-PCR assay showed significantly higher numbers of Streptococcus salivarius, Fusobacterium nucleatum and Porphyromonas gingivalis in patients with ESCC, when compared with healthy controls (all P < 0.05). The areas under the ROC curves for Streptococcus salivarius, Fusobacterium nucleatum, Porphyromonas gingivalis and the combination of the three bacteria for predicting patients with ESCC were 69%, 56.5%, 61.8% and 76.4%, respectively. The sensitivities corresponding to cutoff value were 69.3%, 22.7%, 35.2% and 86.4%, respectively, and the matched specificity were 78.4%, 96.1%, 90.2% and 58.8%, respectively. These highly expressed Streptococcus salivarius, Fusobacterium nucleatum and Porphyromonas gingivalis in the saliva, alone or in combination, indicate their predictive value for ESCC.
基金supported by the National Natural Science Foundation of China(Grant No.31871266)the National Key R&D Program of China(Grant No.2016YFA0100103)+1 种基金the National Natural Science Foundation of China Key Research Grant(Grant No.71532001)supported by funding from Shenzhen Municipal Government of China(Grant No.DRC-SZ[2016]884)。
文摘Genomic studies of cancer cell alterations,such as mutations,copy number variations(CNVs),and translocations,greatly promote our understanding of the genesis and development of cancers.However,the 3D genome architecture of cancers remains less studied due to the complexity of cancer genomes and technical difficulties.To explore the 3D genome structure in clinical lung cancer,we performed Hi-C experiments using paired normal and tumor cells harvested from patients with lung cancer,combining with RNA sequenceing analysis.We demonstrated the feasibility of studying 3D genome of clinical lung cancer samples with a small number of cells(1×10^(4)),compared the genome architecture between clinical samples and cell lines of lung cancer,and identified conserved and changed spatial chromatin structures between normal and cancer samples.We also showed that Hi-C data can be used to infer CNVs and point mutations in cancer.By integrating those different types of cancer alterations,we showed significant associations between CNVs,3D genome,and gene expression.We propose that 3D genome mediates the effects of cancer genomic alterations on gene expression through altering regulatory chromatin structures.Our study highlights the importance of analyzing 3D genomes of clinical cancer samples in addition to cancer cell lines and provides an integrative genomic analysis pipeline for future larger-scale studies in lung cancer and other cancers.
基金Financial support from the Natural Science Foundation of China(21706177 and U19B2003)Guangxi Key Laboratory of Green Chemical Materials and Safety Technology,Beibu Gulf University(2022SYSZZ04)China Petroleum&Chemical Corporation(121014-2).
文摘The oligomerization of light olefins is an alternative for generating clean liquid fuels.In this study,the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring(10 MR)was discussed for 1-hexene oligomerization.MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization.The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite.The MCM-22 zeolite was characterized in detail by NMR,Py-FTIR,and TG analyses.The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated.Structure-activity relationships were established through the kinetic study.Although the density of strong acid sites was essential for the oligomerization of 1-hexene,the presence of low pressure was also necessary for the formation of dimers.Thus,MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.
基金Financial support from the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC,No.18-ZC0607-0007)is gratefully acknowledged.
文摘Selective hydrogenation of Levulinic acid(LA)toγ-Valerolactone(GVL)is an important reaction to produce high value-added chemicals and fuels but remains a big challenge.Herein we reported a Ru/zeolite catalyst with Mn promotion,which exhibited excellent catalytic performance(yield:98%)towards LA to GVL.The intrinsic activity(TOF)also increased obviously with the Mn addition.The particle size of Ru gradually decreased with the increase of Mn loading and a strong interaction between Ru and support was observed for the Ru-Mn/MCM-49 catalyst.The addition of Mn not only offered a good dispersion of Ru species on MCM-49,but also increased the L/B ratio of the catalyst,thereby contributing to the high GVL selectivity.High dispersed Ru sites were the intrinsic active sites of the catalyst verified by the in-situ experimental studies.The dissociation of the reactants was significantly enhanced,resulting in higher catalytic activity.
