Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them...Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.展开更多
Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of ...Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of the pump.Research on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,etc.However,there are few cavitation studies on external herringbone gear pumps.In addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow field.Therefore,it is urgent to study the cavitation characteristics of external herringbone gear pumps.Compared with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is easier.The simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing area.Cavitation can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be achieved.For example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.展开更多
In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugat...In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugate classes of A7</sub>, then we discuss the stabilizer of two points in A7</sub>. Finally, according to the relation between suborbit and orbital, we obtain the orbitals, and determine the orbital graphs.展开更多
Averrhoa carambola is commonly known as star fruit because of its peculiar shape,and its fruit is a rich source of minerals and vitamins.It is also used in traditional medicines in countries such as India,China,the Ph...Averrhoa carambola is commonly known as star fruit because of its peculiar shape,and its fruit is a rich source of minerals and vitamins.It is also used in traditional medicines in countries such as India,China,the Philippines,and Brazil for treating various ailments,including fever,diarrhea,vomiting,and skin disease.Here,we present the first draft genome of the Oxalidaceae family,with an assembled genome size of 470.51 Mb.In total,24,726 protein-coding genes were identified,and 16,490 genes were annotated using various well-known databases.The phylogenomic analysis confirmed the evolutionary position of the Oxalidaceae family.Based on the gene functional annotations,we also identified enzymes that may be involved in important nutritional pathways in the star fruit genome.Overall,the data from this first sequenced genome in the Oxalidaceae family provide an essential resource for nutritional,medicinal,and cultivational studies of the economically important star-fruit plant.展开更多
In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussi...In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.展开更多
In this work, the magnesium aluminum spinel (MgAl2O4) was prepared by Mg and Al as precursors through a method of sol-gel subsequent with high temperature calcination. The wide range of synthetic conditions, including...In this work, the magnesium aluminum spinel (MgAl2O4) was prepared by Mg and Al as precursors through a method of sol-gel subsequent with high temperature calcination. The wide range of synthetic conditions, including organic alcohols, ammonia content, dispersant, alkoxide concentration, hydrolysis time, hydrolysis temperature and calcination temperature were screened over as-prepared samples. This work provides a necessary experimental basis for the synthesis of MgAl2O4 with uniform particle size of spherical structure, which has a potential to be used in many industrial and military applications.展开更多
Nanosystems play an important role in many applications.Due to their complexity,it is challenging to accurately characterize their structure and properties.An important means to reach such a goal is computational simu...Nanosystems play an important role in many applications.Due to their complexity,it is challenging to accurately characterize their structure and properties.An important means to reach such a goal is computational simulation,which is grounded on ab initio electronic structure calculations.Low scaling and accurate electronic-structure algorithms have been developed in recent years.Especially,the efficiency of hybrid density functional calculations for periodic systems has been significantly improved.With electronic structure information,simulation methods can be developed to directly obtain experimentally comparable data.For example,scanning tunneling microscopy images can be effectively simulated with advanced algorithms.When the system we are interested in is strongly coupled to environment,such as the Kondo effect,solving the hierarchical equations of motion turns out to be an effective way of computational characterization.Furthermore,the first principles simulation on the excited state dynamics rapidly emerges in recent years,and nonadiabatic molecular dynamics method plays an important role.For nanosystem involved chemical processes,such as graphene growth,multiscale simulation methods should be developed to characterize their atomic details.In this review,we review some recent progresses in methodology development for computational characterization of nanosystems.Advanced algorithms and software are essential for us to better understand of the nanoworld.展开更多
The traditional feature-extraction method of oriented FAST and rotated BRIEF(ORB)detects image features based on a fixed threshold;however,ORB descriptors do not distinguish features well in capsule endoscopy images.T...The traditional feature-extraction method of oriented FAST and rotated BRIEF(ORB)detects image features based on a fixed threshold;however,ORB descriptors do not distinguish features well in capsule endoscopy images.Therefore,a new feature detector that uses a new method for setting thresholds,called the adaptive threshold FAST and FREAK in capsule endoscopy images(AFFCEI),is proposed.This method,first constructs an image pyramid and then calculates the thresholds of pixels based on the gray value contrast of all pixels in the local neighborhood of the image,to achieve adaptive image feature extraction in each layer of the pyramid.Subsequently,the features are expressed by the FREAK descriptor,which can enhance the discrimination of the features extracted from the stomach image.Finally,a refined matching is obtained by applying the grid-based motion statistics algorithm to the result of Hamming distance,whereby mismatches are rejected using the RANSAC algorithm.Compared with the ASIFT method,which previously had the best performance,the average running time of AFFCEI was 4/5 that of ASIFT,and the average matching score improved by 5%when tracking features in a moving capsule endoscope.展开更多
Designing highly active electrocatalysts for the hydrogen evolution reaction(HER)and oxygen evolution and reduction reactions(OER and ORR)is pivotal to renewable energy technology.Herein,based on density functional th...Designing highly active electrocatalysts for the hydrogen evolution reaction(HER)and oxygen evolution and reduction reactions(OER and ORR)is pivotal to renewable energy technology.Herein,based on density functional theory(DFT)calculations,we systematically investigate the catalytic activity of iron-nitrogen-carbon based covalent organic frameworks(COF)monolayers with axially coordinated ligands(denotes as Fe N_(4)-X@COF,X refers to axial ligand,X=-SCN,-I,-H,-SH,-NO_(2),-Br,-ClO,-Cl,-HCO_(3),-NO,-ClO_(2),-OH,-CN and-F).The calculated results demonstrate that all the catalysts possess good thermodynamic and electrochemical stabilities.The different ligands axially ligated to the Fe active center could induce changes in the charge of the Fe center,which further regulates the interaction strength between intermediates and catalysts that governs the catalytic activity.Importantly,FeN_(4)-SH@COF and Fe N_(4)-OH@COF are efficient bifunctional catalysts for HER and OER,FeN_(4)-OH@COF and FeN_(4)-I@COF are promising bifunctional catalysts for OER and ORR.These findings not only reveal promising bifunctional HER/OER and OER/ORR catalysts but also provide theoretical guidance for designing optimum ironnitrogen-carbon based catalysts.展开更多
Passive daytime radiative cooling(PDRC)technology is emerging as one of the most promising solutions to the global problem of spacing cooling,but its practical application is limited due to reduced cooling effectivene...Passive daytime radiative cooling(PDRC)technology is emerging as one of the most promising solutions to the global problem of spacing cooling,but its practical application is limited due to reduced cooling effectiveness caused by daily wear and tear,as well as dirt contamination.To tackle this problem,we report a novel strategy by introducing a renewable armor structure for prolonging the anti-fouling and cooling effectiveness properties of the PDRC coatings.The armor structure is designed by decorating fluorinated hollow glass microspheres(HGM)inside rigid resin composite matrices.The HGM serve triple purposes,including providing isolated cavities for enhanced solar reflectance,reinforcing the matrices to form robust armored structures,and increasing thermal emittance.When the coatings are worn,the HGM on the surface expose their concave cavities with numerous hydrophobic fragments,generating a highly rough surface that guarantee the superhydrophobic function.The coatings show a high sunlight reflectance(0.93)and thermal emittance(0.94)in the long-wave infrared window,leading to a cooling of 5℃ below ambient temperature under high solar flux(∼900 W/m^(2)).When anti-fouling functions are reduced,they can be regenerated more than 100 cycles without compromising the PDRC function by simple wearing treatment.Furthermore,these coatings can be easily prepared using a one-pot spray method with low-cost materials,exhibit strong adhesion to a variety of substrates,and demonstrate exceptional environmental stability.Therefore,we anticipate their immediate application opportunities for spacing cooling.展开更多
Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a val...Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a validated radioprotectant extensively applied in radiation and chemotherapy medicine,but the short half-life limits its bioavailability and clinical applications,remaining as a great challenge to be addressed.DNAassembled nanostructures especially the tetrahedral framework nucleic acids(tFNAs)are promising nanocarriers with preeminent biosafety,low biotoxicity,and high transport efficiency.The tFNAs also have a relative long-term maintenance for structural stability and excellent endocytosis capacity.We therefore synthesized a tFNA-based delivery system of AMF for multi-organ radioprotection(tFNAs@AMF,also termed nanosuit).By establishing the mice models of accidental total body irradiation(TBI)and radiotherapy model of Lewis lung cancer,we demonstrated that the nanosuit could shield normal cells from IR-induced DNA damage by regulating the molecular biomarkers of anti-apoptosis and anti-oxidative stress.In the accidental total body irradiation(TBI)mice model,the nanosuit pretreated mice exhibited satisfactory alteration of superoxide dismutase(SOD)activities and malondialdehyde(MDA)contents,and functional recovery of hematopoietic system,reducing IRinduced pathological damages of multi-organ and safeguarding mice from lethal radiation.More importantly,the nanosuit showed a selective radioprotection of the normal organs without interferences of tumor control in the radiotherapy model of Lewis lung cancer.Based on a conveniently available DNA tetrahedron-based nanocarrier,this work presents a high-efficiency delivery system of AMF with the prolonged half-life and enhanced radioprotection for multi-organs.Such nanosuit pioneers a promising strategy with great clinical translation potential for radioactivity protection.展开更多
Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique properties.However,the majority of cluster-based assemblies developed so far are either non-magnetic...Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique properties.However,the majority of cluster-based assemblies developed so far are either non-magnetic or only exhibit magnetic ordering with a relatively low Curie temperature,limiting their applications in spintronics.Thus,two-dimensional(2D)cluster-assembled materials with room-temperature magnetism remain highly desirable.For this purpose,based on first principles calculations,we design a series of thermodynamically stable 2D cluster-based metal-organic frameworks(MOFs)Fe_(n)-(pyz)(n=1-6)by utilizing Fenmetal clusters as nodes and nitrogen-containing pyrazine ligands as organic linkers.These 2D cluster-based MOFs exhibit robust ferrimagnetic ordering due to the strong d-p direct exchange interaction between d-electron spin of Fe_(n)(n=1-6)clusters and charge transfer-induced p-electron spin of pyrazine ligands.In particular,the ferrimagnetic Curie temperatures are well above room temperature(up to 836 K).Additionally,altering the size of Fe_(n)clusters in Fe_(n)-(pyz)(n=1-6)MOFs results in diverse functional spintronic properties,including bipolar magnetic semiconductors,half semiconductors and Dirac half metals.Moreover,these 2D assembled MOFs possess sizable magnetic anisotropy energies,up to 9.16 me V per formula.展开更多
It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,densit...It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,density functional theory(DFT)calculations were conducted to systematically investigate a series of TMN_(x)O_(4-x)-HTT(TM=Fe,Co,Ni,Ru,Rh,Pd,Ir and Pt;HTT=hexahydroxy tetraazanaphthotetraphene)analogs of two-dimensional(2D)conductive metal-organic frameworks(MOFs)as potential electrocatalysts for the HER,OER and ORR.The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable.Remarkably,CoO_(4)-HTT,RhN_(3)O_(1)-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER,OER and ORR,respectively,surpassing the catalytic activity of corresponding benchmark catalysts.The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates.The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts,thus achieving optimal catalytic activity.Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.展开更多
Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated c...Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short.Herein,we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix.The generated Co and LiF both enable fast Li-ion diffusion kinetics,meanwhile,the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites,thereby contributing to uniform Li nucleation and non-dendritic growth.As a result,a dendrite-free Li deposition with a low overpotential(16.1 mV)is achieved,which enables an extended lifespan over 750 h under strict conditions.The full cells with high-mass-loading LiFePO_(4)(11.5 mg/cm^(2))as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4%after undergoing 180 cycles.展开更多
The chemoselective hydrogenation of structurally diverse nitroaromatics is a challenging process.Generally,catalyst activity tends to decrease when excellent selectivity is guaranteed.We here present a novel photocata...The chemoselective hydrogenation of structurally diverse nitroaromatics is a challenging process.Generally,catalyst activity tends to decrease when excellent selectivity is guaranteed.We here present a novel photocatalyst combining amino-functionalized carbon dots(N-CDs)with copper selenite nanoparticles(N-CDs@CuSeO_(3))for simultaneously improving selectivity and activity.Under visible light irradiation,the prepared N-CDs@CuSeO_(3)exhibits 100%catalytic selectivity for the formation of 4-aminostyrene at full conversion of 4-nitrostyrene in aqueous solvent within a few minutes.Such excellent photocatalytic performance is mainly attributed to the precise control of the hydrogen species released from the ammonia borane by means of light-converted electrons upon N-CDs@CuSeO_(3).Besides,the defect states at the interface of N-CDs and CuSeO_(3)enable holes to be trapped for promoting separation and transfer of photogenerated charges,allowing more hydrogen species to participate in catalytic reaction.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)causes multi-organ damage,which includes hepatic dysfunction,as observed in over 50%of COVID-19 patients.Angiotensin I converting enzyme(peptidyl-dipeptidase ...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)causes multi-organ damage,which includes hepatic dysfunction,as observed in over 50%of COVID-19 patients.Angiotensin I converting enzyme(peptidyl-dipeptidase A)2(ACE2)is the primary receptor for SARS-CoV-2 entry into host cells,and studies have shown the presence of intracellular virus particles in human hepatocytes that express ACE2,but at extremely low levels.Consequently,we asked if hepatocytes might express receptors other than ACE2 capable of promoting the entry of SARS-CoV-2 into cells.To address this question,we performed a genome-wide CRISPR-Cas9 activation library screening and found that Asialoglycoprotein receptor 1(ASGR1)promoted SARS-CoV-2 pseudovirus infection of HeLa cells.In Huh-7 cells,simultaneous knockout of ACE2 and ASGR1 prevented SARS-CoV-2 pseudovirus infection.In the immortalized THLE-2 hepatocyte cell line and primary hepatic parenchymal cells,both of which barely expressed ACE2,SARSCoV-2 pseudovirus could successfully establish an infection.However,after treatment with ASGR1 antibody or siRNA targeting ASGR1,the infection rate significantly dropped,suggesting that SARS-CoV-2 pseudovirus infects hepatic parenchymal cells mainly through an ASGR1-dependent mechanism.We confirmed that ASGR1 could interact with Spike protein,which depends on receptor binding domain(RBD)and N-terminal domain(NTD).Finally,we also used Immunohistochemistry and electron microscopy to verify that SARS-CoV-2 could infect primary hepatic parenchymal cells.After inhibiting ASGR1 in primary hepatic parenchymal cells by siRNA,the infection efficiency of the live virus decreased significantly.Collectively,these findings indicate that ASGR1 is a candidate receptor for SARS-CoV-2 that promotes infection of hepatic parenchymal cells.展开更多
Repelling liquid drops from engineering surfaces has attracted great attention in a variety of applications.To achieve efficient liquid shedding,delicate surface textures are often introduced to sustain air pockets at...Repelling liquid drops from engineering surfaces has attracted great attention in a variety of applications.To achieve efficient liquid shedding,delicate surface textures are often introduced to sustain air pockets at the liquid-solid interface.However,those surfaces are prone to suffer from mechanical failure,which may bring reliability issues and thus limits their applications.Here,inspired by the aerodynamic Leidenfrost effect,we present that impacting drops are directionally repelled from smooth surfaces supplied with an exogenous air layer.Our theoretical analysis reveals that the synchronized nonwetting and oblique bouncing behavior is attributed to the aerodynamic force arising from the air layer.The versatility and practicability of our approach allow for drop repellency without the aid of any surface wettability treatment and also avoid the consideration of mechanical stability issues,which thereby provides a promising candidate for the applications that necessitate liquid shedding,e.g.,resolve the problem of tiny raindrop adhesion on the automobile side window during driving.展开更多
Low-cost porous ceramic microspheres from waste gangue were prepared by simple spray drying and subsequent calcination. Effects of calcination temperature on phase and microstructure evolution, specific surface area, ...Low-cost porous ceramic microspheres from waste gangue were prepared by simple spray drying and subsequent calcination. Effects of calcination temperature on phase and microstructure evolution, specific surface area, pore structure, and dye adsorption mechanism of the microspheres were investigated systematically. Results showed that the microspheres were spherical, with some mesopores both on the surface and inside the spheres. The phase kept kaolinite after calcined at 800 and 900 ℃ and transformed into mullite at 1000 ℃. The microspheres calcined at 800 ℃ showed larger adsorption capacity and removal efficiency than those calcined at higher temperatures. Methylene blue(MB) and basic fuchsin(BF) removal efficiency reached 100% and 99.9% with the microsphere dosage of 20 g/L, respectively, which was comparable to that of other low-cost waste adsorbents used to remove dyes in the literature. Adsorption kinetics data followed the pseudosecond-order kinetic model, and the isotherm data fit the Langmuir isotherm model. The adsorption process was attributed to multiple adsorption mechanisms including physical adsorption, hydrogen bonding, and electrostatic interactions between dyes and gangue microspheres. The low-cost porous microspheres with excellent cyclic regeneration properties are promising absorbent for dyes in wastewater filtration and adsorption treatment.展开更多
基金the financial support from Shenzhen Science and Technology Program (JCYJ20210324142210027, X.D.)the National Natural Science Foundation of China (52103136, 22275028, U22A20153, 22102017, 22302033, and 52106194)+5 种基金the Sichuan Outstanding Young Scholars Foundation (2021JDJQ0013)Natural Science Foundation of Sichuan Province (2022NSFSC1271)Sichuan Science and Technology Program (2023JDRC0082)“Oncology Medical Engineering Innovation Foundation” project of University of Electronic Science and Technology of China and Sichuan Cancer Hospital (ZYGX2021YGCX009)“Medical and Industrial Cross Foundation” of University of Electronic Science and Technology of China and Sichuan Provincial People’s Hospital (ZYGX2021YGLH207)Shandong Key R&D grant (2022CXGC010509)。
文摘Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.
基金supported by a Grant(2024-MOIS35-005)of Policy-linked Technology Development Program on Natural Disaster Prevention and Mitigation funded by Ministry of Interior and Safety(MOIS,Korea).
文摘Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of the pump.Research on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,etc.However,there are few cavitation studies on external herringbone gear pumps.In addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow field.Therefore,it is urgent to study the cavitation characteristics of external herringbone gear pumps.Compared with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is easier.The simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing area.Cavitation can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be achieved.For example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.
文摘In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugate classes of A7</sub>, then we discuss the stabilizer of two points in A7</sub>. Finally, according to the relation between suborbit and orbital, we obtain the orbitals, and determine the orbital graphs.
基金supported by funding from the National Key R&D Program of China(No.2019YFC1711000)the Shenzhen Municipal Government of China(grants JCYJ20170817145512476 and JCYJ20160510141910129)+1 种基金the Guangdong Provincial Key Laboratory of Genome Read and Write(grant 2017B030301011)the NMPA Key Laboratory for the Rapid Testing Technology of Drugs.
文摘Averrhoa carambola is commonly known as star fruit because of its peculiar shape,and its fruit is a rich source of minerals and vitamins.It is also used in traditional medicines in countries such as India,China,the Philippines,and Brazil for treating various ailments,including fever,diarrhea,vomiting,and skin disease.Here,we present the first draft genome of the Oxalidaceae family,with an assembled genome size of 470.51 Mb.In total,24,726 protein-coding genes were identified,and 16,490 genes were annotated using various well-known databases.The phylogenomic analysis confirmed the evolutionary position of the Oxalidaceae family.Based on the gene functional annotations,we also identified enzymes that may be involved in important nutritional pathways in the star fruit genome.Overall,the data from this first sequenced genome in the Oxalidaceae family provide an essential resource for nutritional,medicinal,and cultivational studies of the economically important star-fruit plant.
基金supported by the National Natural Science Foundation of China(6130501761304264+1 种基金61402203)the Natural Science Foundation of Jiangsu Province(BK20130154)
文摘In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.
文摘In this work, the magnesium aluminum spinel (MgAl2O4) was prepared by Mg and Al as precursors through a method of sol-gel subsequent with high temperature calcination. The wide range of synthetic conditions, including organic alcohols, ammonia content, dispersant, alkoxide concentration, hydrolysis time, hydrolysis temperature and calcination temperature were screened over as-prepared samples. This work provides a necessary experimental basis for the synthesis of MgAl2O4 with uniform particle size of spherical structure, which has a potential to be used in many industrial and military applications.
基金supported by the Ministry of Science and Technology(No.2016YFA0200604)。
文摘Nanosystems play an important role in many applications.Due to their complexity,it is challenging to accurately characterize their structure and properties.An important means to reach such a goal is computational simulation,which is grounded on ab initio electronic structure calculations.Low scaling and accurate electronic-structure algorithms have been developed in recent years.Especially,the efficiency of hybrid density functional calculations for periodic systems has been significantly improved.With electronic structure information,simulation methods can be developed to directly obtain experimentally comparable data.For example,scanning tunneling microscopy images can be effectively simulated with advanced algorithms.When the system we are interested in is strongly coupled to environment,such as the Kondo effect,solving the hierarchical equations of motion turns out to be an effective way of computational characterization.Furthermore,the first principles simulation on the excited state dynamics rapidly emerges in recent years,and nonadiabatic molecular dynamics method plays an important role.For nanosystem involved chemical processes,such as graphene growth,multiscale simulation methods should be developed to characterize their atomic details.In this review,we review some recent progresses in methodology development for computational characterization of nanosystems.Advanced algorithms and software are essential for us to better understand of the nanoworld.
基金the National Natural Science Foundation of China,No.62172190the“Double Creation”Plan of Jiangsu Province,No.JSSCRC2021532and the“Taihu Talent-Innovative Leading Talent”Plan of Wuxi City.
文摘The traditional feature-extraction method of oriented FAST and rotated BRIEF(ORB)detects image features based on a fixed threshold;however,ORB descriptors do not distinguish features well in capsule endoscopy images.Therefore,a new feature detector that uses a new method for setting thresholds,called the adaptive threshold FAST and FREAK in capsule endoscopy images(AFFCEI),is proposed.This method,first constructs an image pyramid and then calculates the thresholds of pixels based on the gray value contrast of all pixels in the local neighborhood of the image,to achieve adaptive image feature extraction in each layer of the pyramid.Subsequently,the features are expressed by the FREAK descriptor,which can enhance the discrimination of the features extracted from the stomach image.Finally,a refined matching is obtained by applying the grid-based motion statistics algorithm to the result of Hamming distance,whereby mismatches are rejected using the RANSAC algorithm.Compared with the ASIFT method,which previously had the best performance,the average running time of AFFCEI was 4/5 that of ASIFT,and the average matching score improved by 5%when tracking features in a moving capsule endoscope.
基金supported by the National Natural Science Foundation of China(Nos.22102167 and U21A20317)。
文摘Designing highly active electrocatalysts for the hydrogen evolution reaction(HER)and oxygen evolution and reduction reactions(OER and ORR)is pivotal to renewable energy technology.Herein,based on density functional theory(DFT)calculations,we systematically investigate the catalytic activity of iron-nitrogen-carbon based covalent organic frameworks(COF)monolayers with axially coordinated ligands(denotes as Fe N_(4)-X@COF,X refers to axial ligand,X=-SCN,-I,-H,-SH,-NO_(2),-Br,-ClO,-Cl,-HCO_(3),-NO,-ClO_(2),-OH,-CN and-F).The calculated results demonstrate that all the catalysts possess good thermodynamic and electrochemical stabilities.The different ligands axially ligated to the Fe active center could induce changes in the charge of the Fe center,which further regulates the interaction strength between intermediates and catalysts that governs the catalytic activity.Importantly,FeN_(4)-SH@COF and Fe N_(4)-OH@COF are efficient bifunctional catalysts for HER and OER,FeN_(4)-OH@COF and FeN_(4)-I@COF are promising bifunctional catalysts for OER and ORR.These findings not only reveal promising bifunctional HER/OER and OER/ORR catalysts but also provide theoretical guidance for designing optimum ironnitrogen-carbon based catalysts.
基金supported by the National Natural Science Foundation of China(Nos.52003035,52203135 and 51973023)the CHN Energy Group Project(No.GJNY-21-183).
文摘Passive daytime radiative cooling(PDRC)technology is emerging as one of the most promising solutions to the global problem of spacing cooling,but its practical application is limited due to reduced cooling effectiveness caused by daily wear and tear,as well as dirt contamination.To tackle this problem,we report a novel strategy by introducing a renewable armor structure for prolonging the anti-fouling and cooling effectiveness properties of the PDRC coatings.The armor structure is designed by decorating fluorinated hollow glass microspheres(HGM)inside rigid resin composite matrices.The HGM serve triple purposes,including providing isolated cavities for enhanced solar reflectance,reinforcing the matrices to form robust armored structures,and increasing thermal emittance.When the coatings are worn,the HGM on the surface expose their concave cavities with numerous hydrophobic fragments,generating a highly rough surface that guarantee the superhydrophobic function.The coatings show a high sunlight reflectance(0.93)and thermal emittance(0.94)in the long-wave infrared window,leading to a cooling of 5℃ below ambient temperature under high solar flux(∼900 W/m^(2)).When anti-fouling functions are reduced,they can be regenerated more than 100 cycles without compromising the PDRC function by simple wearing treatment.Furthermore,these coatings can be easily prepared using a one-pot spray method with low-cost materials,exhibit strong adhesion to a variety of substrates,and demonstrate exceptional environmental stability.Therefore,we anticipate their immediate application opportunities for spacing cooling.
基金supported by National Natural Science Foundation of China(82370929)Sichuan Science and Technology Program(2022NSFSC0002 and 2024NSFSC3508)+4 种基金Sichuan Province Youth Science and Technology Innovation Team(2022JDTD0021)Research and Develop Program,West China Hospital of Stomatology Sichuan University(RD03202302,RCDWJS2024-1)China Postdoctoral Science Foundation(GZB2023470)Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows(BX202317)The authors would like to thank Dr.Chenghui Li(Analytical&Testing Center,Sichuan University)for technical assistance in assisting with the particle size analysis.
文摘Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a validated radioprotectant extensively applied in radiation and chemotherapy medicine,but the short half-life limits its bioavailability and clinical applications,remaining as a great challenge to be addressed.DNAassembled nanostructures especially the tetrahedral framework nucleic acids(tFNAs)are promising nanocarriers with preeminent biosafety,low biotoxicity,and high transport efficiency.The tFNAs also have a relative long-term maintenance for structural stability and excellent endocytosis capacity.We therefore synthesized a tFNA-based delivery system of AMF for multi-organ radioprotection(tFNAs@AMF,also termed nanosuit).By establishing the mice models of accidental total body irradiation(TBI)and radiotherapy model of Lewis lung cancer,we demonstrated that the nanosuit could shield normal cells from IR-induced DNA damage by regulating the molecular biomarkers of anti-apoptosis and anti-oxidative stress.In the accidental total body irradiation(TBI)mice model,the nanosuit pretreated mice exhibited satisfactory alteration of superoxide dismutase(SOD)activities and malondialdehyde(MDA)contents,and functional recovery of hematopoietic system,reducing IRinduced pathological damages of multi-organ and safeguarding mice from lethal radiation.More importantly,the nanosuit showed a selective radioprotection of the normal organs without interferences of tumor control in the radiotherapy model of Lewis lung cancer.Based on a conveniently available DNA tetrahedron-based nanocarrier,this work presents a high-efficiency delivery system of AMF with the prolonged half-life and enhanced radioprotection for multi-organs.Such nanosuit pioneers a promising strategy with great clinical translation potential for radioactivity protection.
基金supported by the National Natural Science Foundation of China(22288201,22273092,22322304)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Youth Innovation Promotion Association CAS(2019441)the Innovation Program for Quantum Science and Technology(2021ZD0303306)USTC Tang Scholar。
文摘Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique properties.However,the majority of cluster-based assemblies developed so far are either non-magnetic or only exhibit magnetic ordering with a relatively low Curie temperature,limiting their applications in spintronics.Thus,two-dimensional(2D)cluster-assembled materials with room-temperature magnetism remain highly desirable.For this purpose,based on first principles calculations,we design a series of thermodynamically stable 2D cluster-based metal-organic frameworks(MOFs)Fe_(n)-(pyz)(n=1-6)by utilizing Fenmetal clusters as nodes and nitrogen-containing pyrazine ligands as organic linkers.These 2D cluster-based MOFs exhibit robust ferrimagnetic ordering due to the strong d-p direct exchange interaction between d-electron spin of Fe_(n)(n=1-6)clusters and charge transfer-induced p-electron spin of pyrazine ligands.In particular,the ferrimagnetic Curie temperatures are well above room temperature(up to 836 K).Additionally,altering the size of Fe_(n)clusters in Fe_(n)-(pyz)(n=1-6)MOFs results in diverse functional spintronic properties,including bipolar magnetic semiconductors,half semiconductors and Dirac half metals.Moreover,these 2D assembled MOFs possess sizable magnetic anisotropy energies,up to 9.16 me V per formula.
基金supported by the National Natural Science Foundation of China(Nos.22102167 and U21A20317).
文摘It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,density functional theory(DFT)calculations were conducted to systematically investigate a series of TMN_(x)O_(4-x)-HTT(TM=Fe,Co,Ni,Ru,Rh,Pd,Ir and Pt;HTT=hexahydroxy tetraazanaphthotetraphene)analogs of two-dimensional(2D)conductive metal-organic frameworks(MOFs)as potential electrocatalysts for the HER,OER and ORR.The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable.Remarkably,CoO_(4)-HTT,RhN_(3)O_(1)-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER,OER and ORR,respectively,surpassing the catalytic activity of corresponding benchmark catalysts.The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates.The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts,thus achieving optimal catalytic activity.Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.
基金financially supported by the National Natural Science Foundation of China(Nos.22279097,52172217)Natural Science Foundation of Guangdong Province(No.2021A1515010144)Shenzhen Science and Technology Program(No.JCYJ20210324120400002).
文摘Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short.Herein,we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix.The generated Co and LiF both enable fast Li-ion diffusion kinetics,meanwhile,the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites,thereby contributing to uniform Li nucleation and non-dendritic growth.As a result,a dendrite-free Li deposition with a low overpotential(16.1 mV)is achieved,which enables an extended lifespan over 750 h under strict conditions.The full cells with high-mass-loading LiFePO_(4)(11.5 mg/cm^(2))as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4%after undergoing 180 cycles.
基金Fundamental Research Program of Shanxi Province of China(No.20210302123037)Research Project Supported by Shanxi Scholarship Council of China(No.2022-136)Specialized Research Fund for Sanjin Scholars Program of Shanxi Province of China.
文摘The chemoselective hydrogenation of structurally diverse nitroaromatics is a challenging process.Generally,catalyst activity tends to decrease when excellent selectivity is guaranteed.We here present a novel photocatalyst combining amino-functionalized carbon dots(N-CDs)with copper selenite nanoparticles(N-CDs@CuSeO_(3))for simultaneously improving selectivity and activity.Under visible light irradiation,the prepared N-CDs@CuSeO_(3)exhibits 100%catalytic selectivity for the formation of 4-aminostyrene at full conversion of 4-nitrostyrene in aqueous solvent within a few minutes.Such excellent photocatalytic performance is mainly attributed to the precise control of the hydrogen species released from the ammonia borane by means of light-converted electrons upon N-CDs@CuSeO_(3).Besides,the defect states at the interface of N-CDs and CuSeO_(3)enable holes to be trapped for promoting separation and transfer of photogenerated charges,allowing more hydrogen species to participate in catalytic reaction.
基金supported by the National Natural Science Foundation of China(82041001,31771484,81761128020,92169112)。
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)causes multi-organ damage,which includes hepatic dysfunction,as observed in over 50%of COVID-19 patients.Angiotensin I converting enzyme(peptidyl-dipeptidase A)2(ACE2)is the primary receptor for SARS-CoV-2 entry into host cells,and studies have shown the presence of intracellular virus particles in human hepatocytes that express ACE2,but at extremely low levels.Consequently,we asked if hepatocytes might express receptors other than ACE2 capable of promoting the entry of SARS-CoV-2 into cells.To address this question,we performed a genome-wide CRISPR-Cas9 activation library screening and found that Asialoglycoprotein receptor 1(ASGR1)promoted SARS-CoV-2 pseudovirus infection of HeLa cells.In Huh-7 cells,simultaneous knockout of ACE2 and ASGR1 prevented SARS-CoV-2 pseudovirus infection.In the immortalized THLE-2 hepatocyte cell line and primary hepatic parenchymal cells,both of which barely expressed ACE2,SARSCoV-2 pseudovirus could successfully establish an infection.However,after treatment with ASGR1 antibody or siRNA targeting ASGR1,the infection rate significantly dropped,suggesting that SARS-CoV-2 pseudovirus infects hepatic parenchymal cells mainly through an ASGR1-dependent mechanism.We confirmed that ASGR1 could interact with Spike protein,which depends on receptor binding domain(RBD)and N-terminal domain(NTD).Finally,we also used Immunohistochemistry and electron microscopy to verify that SARS-CoV-2 could infect primary hepatic parenchymal cells.After inhibiting ASGR1 in primary hepatic parenchymal cells by siRNA,the infection efficiency of the live virus decreased significantly.Collectively,these findings indicate that ASGR1 is a candidate receptor for SARS-CoV-2 that promotes infection of hepatic parenchymal cells.
基金support by the National Natural Science Foundation of China(22202035,22072014,and 22102017)the Chengdu Science and Technology Bureau(2021-GH02-00105-HZ)+3 种基金the Shenzhen Science and Technology Program(JCYJ20210324142210027)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(2021ZYD0046)the Sichuan Outstanding Young Scholars Foundation(2021JDJQ0013)the Sichuan Science and Technology Program(2021JDRC0016).
文摘Repelling liquid drops from engineering surfaces has attracted great attention in a variety of applications.To achieve efficient liquid shedding,delicate surface textures are often introduced to sustain air pockets at the liquid-solid interface.However,those surfaces are prone to suffer from mechanical failure,which may bring reliability issues and thus limits their applications.Here,inspired by the aerodynamic Leidenfrost effect,we present that impacting drops are directionally repelled from smooth surfaces supplied with an exogenous air layer.Our theoretical analysis reveals that the synchronized nonwetting and oblique bouncing behavior is attributed to the aerodynamic force arising from the air layer.The versatility and practicability of our approach allow for drop repellency without the aid of any surface wettability treatment and also avoid the consideration of mechanical stability issues,which thereby provides a promising candidate for the applications that necessitate liquid shedding,e.g.,resolve the problem of tiny raindrop adhesion on the automobile side window during driving.
基金funded by China Postdoctoral Science Foundation(Grant No.2017M610085)National Natural Science Foundation of China(NSFC,Nos.51702184 and 51572140)
文摘Low-cost porous ceramic microspheres from waste gangue were prepared by simple spray drying and subsequent calcination. Effects of calcination temperature on phase and microstructure evolution, specific surface area, pore structure, and dye adsorption mechanism of the microspheres were investigated systematically. Results showed that the microspheres were spherical, with some mesopores both on the surface and inside the spheres. The phase kept kaolinite after calcined at 800 and 900 ℃ and transformed into mullite at 1000 ℃. The microspheres calcined at 800 ℃ showed larger adsorption capacity and removal efficiency than those calcined at higher temperatures. Methylene blue(MB) and basic fuchsin(BF) removal efficiency reached 100% and 99.9% with the microsphere dosage of 20 g/L, respectively, which was comparable to that of other low-cost waste adsorbents used to remove dyes in the literature. Adsorption kinetics data followed the pseudosecond-order kinetic model, and the isotherm data fit the Langmuir isotherm model. The adsorption process was attributed to multiple adsorption mechanisms including physical adsorption, hydrogen bonding, and electrostatic interactions between dyes and gangue microspheres. The low-cost porous microspheres with excellent cyclic regeneration properties are promising absorbent for dyes in wastewater filtration and adsorption treatment.
