Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,r...Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,resulting in smaller homologous compounds.Due to the lack of standard substances for debromination products,the in-depth study of DBDPE environmental geochemical behavior through debromination conversion has been hindered.Therefore,based on DBDPE photodegradation experiment,this study first analyzed and identified the brominated products of DBDPE using high-performance liquid chromatography-atmospheric pressure photoionization-time of flight mass spectrometry(HPLC-APPI-TOF/MS).Four debromination products-nonabromodiphenyl ethane(nonaBDPE),octabromodiphenyl ethane(octa-BDPE),heptabromodiphenyl ethane(hepta-BDPE)and hexabromodiphenyl ethane(hexa-BDPE)are identified based on the characteristic ion peak of[M-Br+O]^(-) in negative ion mode.Subsequently,using methanol as the mobile phase,four debromination products of DBDPE were separated and purified with a semi-preparative high-performance liquid chromatography(SP-HPLC)system equipped with an Agilent Zorbax Eclipse PAH column(4.6 mm×250 mm,5μm).The first-time acquisition of hexa-BDPE(60.00μg),octa-BDPE(19.40μg),hepta-BDPE(31.20μg)and octa-BDPE(isomer,45.20μg)with purity exceeding 90%has been achieved.Among them,the purity of one hepta-BDPE monomer is as high as 98.91%.This study indicates that based on photodegradation experiments,the combination of HPLC-APPI-TOF/MS and SP-HPLC techniques can rapidly identify and prepare DBDPE debrominated products.This approach meets the requirements for preliminary research on the pollution characteristics of DBDPE debrominated compounds and offers a feasible solution for the preparation of standard reference materials for emerging pollutants.展开更多
In this paper, we consider the problems of data sharing between multiple distrusted authorities. Prior solutions rely on trusted third parties such as CAs, or are susceptible to collusion between malicious authorities...In this paper, we consider the problems of data sharing between multiple distrusted authorities. Prior solutions rely on trusted third parties such as CAs, or are susceptible to collusion between malicious authorities, which can comprise the security of honest ones. In this paper, we propose a new multi-authority data sharing scheme - Decen- tralized Multi-Authority ABE （DMA）, which is derived from CP-ABE that is resilient to these types of misbehavior. Our system distin- guishes between a data owner （DO） principal and attribute authorities （AAs）： the DO owns the data but allows AAs to arbitrate access by providing attribute labels to users. The data is protected by policy encryption over these attributes. Unlike prior systems, attributes generated by AAs are not user-specific, and neither is the system susceptible to collusion between users who try to escalate their access by sharing keys. We prove our scherne correct under the Decisional Bilinear Diffie-Hellman （DBDH） assumption; we also include a com- plete end-to-end implementation that demon- strates the practical efficacy of our technique.展开更多
A novel bidirectional remotely controlled device for static and dynamic compression/decompression using diamond anvil cells(DACs)has been developed that can control pressure in an accurate and consistent manner.Electr...A novel bidirectional remotely controlled device for static and dynamic compression/decompression using diamond anvil cells(DACs)has been developed that can control pressure in an accurate and consistent manner.Electromechanical piezoelectric actuators are applied to a conventional DAC,allowing applications under a variety of pressure conditions.Using this static and dynamic DAC(s-dDAC),it is possible to addresses the poorly studied experimental regime lying between purely static and purely dynamic studies.The s-dDAC,driven by three piezoelectric actuators,can be combined with a time-resolved spectral measurement system and high-speed imaging device to study the structural changes,chemical reactions,and properties of materials under extreme conditions.The maximum compression/decompression rate or pressure range highly depends on the culet size of the anvil,and a higher compression rate and wider pressure range can be realized in a DAC with smaller anvil culet.With our s-dDAC,we have been able to achieve the highest compression rate to date with a 300μm culet anvil:48 TPa/s.An overview of a variety of experimental measurements possible with our device is presented.展开更多
In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element ...In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element Particle-In-Cell Monte-Carlo-Collision(IFE-PIC-MCC)method and the grid erosion evaluation model.The transport process of beam ions and Charge Exchange(CEX)ions in the grid system,and the characteristics and mechanisms of the aperture barrel erosion under extreme erosion conditions(i.e.the cylindrical erosion and chamfer erosion)were systematically studied.Thanks to the advantage of the IFE method for dealing with complex boundaries in structured mesh,the aperture barrel erosion morphology of the accelerator grid is reconstructed accurately based on the experimental results.The results show that,with the evolution of working conditions,the mechanism of the aperture barrel erosion changes significantly,which relies heavily on the accelerator grid morphology.The change of the accelerator grid aperture barrel morphology has a significant effect on the behavior of CEX ions,and only affects the local electric field distribution,but has no effect on the upstream plasma sheath.As the erosion progresses,the erosion position moves downstream along the grid aperture axis direction,and the erosion range becomes narrower.Regardless of the erosion phase,the erosion rate of the CEX ions located downstream of the decelerator grid is the largest.The erosion rate is related to the mean incident energy and angle,and their variation is closely related to the position and trajectory of CEXions.展开更多
Objective To investigate N-myc downstream-regulated gene 2(NDRG2) expression in ovarian cancer cells and its potential usefulness as a diagnostic marker and/or target for therapeutic intervention.Methods Human NDRG2 L...Objective To investigate N-myc downstream-regulated gene 2(NDRG2) expression in ovarian cancer cells and its potential usefulness as a diagnostic marker and/or target for therapeutic intervention.Methods Human NDRG2 L/S gene was obtained by revers-transcription polymerase chain reaction(RT-PCR). Sequence analysis confirmed the identity of NDRG2 L/S gene, which was then inserted into a eukaryotic vector p LNCX2, which was in turn transfected into NDRG2 gene-negative HO-8910 cells. Flow cytometry(FCM) and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assay were conducted to determine the proliferation rate of HO-8910 cells. Cisplatin resistance of HO-8910 cells transfected with p LNCX2-NDRG2 L/S was evaluated by FCM. Tumors were generated in female nude mice by subcutaneous injection of HO-8910 cells.Results NDRG2 gene was isolated and its expression vector was successfully constructed. NDRG2 expression positively correlated with the proliferation of HO-8910 cells. NDRG2 L/S promoted tumorigenicity in HO-8910 cells.Conclusion The present study identified a novel function of NDRG2 L/S gene and demonstrated its involvement in the promotion of ovarian cancer cell proliferation and enhancement of cisplatin resistance in HO-8910 cells. Future studies are warranted to determine the relationship between NDRG2 upregulation and ovarian cancer progression.展开更多
Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,c...Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.展开更多
1Introduction Due to the easy loss and decomposition of traditional chemical pesticides,their repeated application in agriculture results in serious environmental risks to the surrounding environment and organisms.Con...1Introduction Due to the easy loss and decomposition of traditional chemical pesticides,their repeated application in agriculture results in serious environmental risks to the surrounding environment and organisms.Controlledrelease nanopesticides are attracting attention as a promising technology in agriculture due to their unique structure and effects(e.g.,nano-size scale,interfacial effects,and effective insecticidal time)(An et al.,2022).Their application could improve insecticidal efficacies,decrease usage amounts,and reduce the potential environmental impacts of chemical pesticides.展开更多
Citrus blue mold. is an important disease of Citrus postharvest storage and transportation, and a major factor affecting the long-term storage of citrus. The pathogens, harm symptoms as well as the infection circulati...Citrus blue mold. is an important disease of Citrus postharvest storage and transportation, and a major factor affecting the long-term storage of citrus. The pathogens, harm symptoms as well as the infection circulation of Citrus blue mold were introduced, followed by a summary of the progress on the biological control of Citrus blue mold in recent years, with the aim to provide references for the prevention and control of Citrus blue mold.展开更多
Qingshu 9 was approved and formally named as a new potato variety by Qinghai Crop Variety Approval Committee in December 2006. It has outstanding features of high quality, high yield, drought resistance, and disease r...Qingshu 9 was approved and formally named as a new potato variety by Qinghai Crop Variety Approval Committee in December 2006. It has outstanding features of high quality, high yield, drought resistance, and disease resistance. Hanzhong Institute of Agricultural Sciences introduced Qingshu 9 from Dingxi County in Gansu Province in 2010. Through years of experiments and demonstrations, the average yield of Qingshu can reach up to 53.14 t/hm^2 with the maximum yield to 63.77 t/hm^2.展开更多
In situ strain photoluminescence （PL） and Raman spectroscopy have been employed to exploit the evolutions of the electronic band structure and lattice vibrational responses of chemical vapor deposition （CVD）-grown...In situ strain photoluminescence （PL） and Raman spectroscopy have been employed to exploit the evolutions of the electronic band structure and lattice vibrational responses of chemical vapor deposition （CVD）-grown monolayer tungsten disulphide （WS2） under uniaxial tensile strain. Observable broadening and appearance of an extra small feature at the longer-wavelength side shoulder of the PL peak occur under 2.5% strain, which could indicate the direct-indirect bandgap transition and is further confirmed by our density-functional-theory calculations. As the strain increases further, the spectral weight of the indirect transition gradually increases. Over the entire strain range, with the increase of the strain, the light emissions corresponding to each optical transition, such as the direct bandgap transition （K-K） and indirect bandgap transition （F-K, ≥2.5%）, exhibit a monotonous linear redshift. In addition, the binding energy of the indirect transition is found to be larger than that of the direct transition, and the slight lowering of the trion dissociation energy with increasing strain is observed. The strain was used to modulate not only the electronic band structure but also the lattice vibrations. The softening and splitting of the in-plane E＇ mode is observed under uniaxial tensile strain, and polarization-dependent Raman spectroscopy confirms the observed zigzag-oriented edge of WS2 grown by CVD in previous studies. These findings enrich our understanding of the strained states of monolayer transition-metal dichalcogenide （TMD） materials and lay a foundation for developing applications exploiting their strain-dependent optical properties, including the strain detection and light-emission modulation of such emerging two-dimensional TMDs.展开更多
We report the thermal conductivities of monolayer （1L） and bilayer （2L） WS2 grown by chemical vapor deposition （CVD）, which are determined by use of temperature and excitation dependences of E2g^1 and A1g Raman ...We report the thermal conductivities of monolayer （1L） and bilayer （2L） WS2 grown by chemical vapor deposition （CVD）, which are determined by use of temperature and excitation dependences of E2g^1 and A1g Raman modes. The first-order temperature coefficients of E2g^1 and Alg modes in both supported and suspended WS2 layers were extracted. The frequency shift of the A3g mode with temperature is larger than that of the E1 mode for 1L-WS2, which is 2g attributed to stronger electron-phonon coupling for the A1g mode than that for the E12g mode. Moreover, by use of the shift of the phonon mode induced by laser heating, the thermal conductivities at room temperature were estimated to be 32 and 53 W/（m.K） for 1L- and 2L-WS2, respectively. Our results provide fundamental information about the thermal properties of WS2 layers, which is crucial for developing applications of atomically-thin WS2 devices.展开更多
Black phosphorus （BP） is a good candidate for studying strain effects on two- dimensional （2D） materials beyond graphene and transition-metal dichalcogenides. This is because of its particular ability to sustain h...Black phosphorus （BP） is a good candidate for studying strain effects on two- dimensional （2D） materials beyond graphene and transition-metal dichalcogenides. This is because of its particular ability to sustain high strain and remarkably anisotropic mechanical properties resulting from its unique puckered structure. We here investigate the dependence of lattice vibrational frequencies on cry- stallographic orientations in uniaxially strained few-layer BP by in-situ strained Raman spectroscopy. The out-of-plane A1 mode is sensitive to uniaxial strain along the near-armchair direction whereas the in-plane B2g and A2 modes are sensitive to strain in the near-zigzag direction. For uniaxial strains applied away from these directions, all three phonon modes are linearly redshifted. Our experimental observation is explained by the anisotropic influence of uniaxial tensile strain on structural properties of BP using density functional theory. This study demonstrates the possibility of selective tuning of in-plane and out-of-plane phonon modes in BP by uniaxial strain and makes strain engineering a promising avenue for extensively modulating the optical and mechanical properties of 2D materials.展开更多
Twisted van der Waals homo-and hetero-structures have aroused great attentions due to their unique physical properties,providing a new platform to explore the novel two-dimensional(2D)condensed matter physics.The robu...Twisted van der Waals homo-and hetero-structures have aroused great attentions due to their unique physical properties,providing a new platform to explore the novel two-dimensional(2D)condensed matter physics.The robust dependence of phonon vibrations and electronic band structures on the twist angle has been intensively observed in transition metal dichalcogenide(TMD)homo-structures.However,the effects of twist angle on the lattice vibrational properties in the TMD heterostructures have not caused enough attention.Here,we report the distinct evolutions of Raman scattering and the underlying interlayer interactions in the twisted WS_(2)/MoS_(2) heterostructures.The shifts and linewidths of E_(2g)(Γ)and A_(1g)(Γ)phonon modes are found to be twist angle dependent.In particular,analogous to that of the twisted TMD homostructures,the frequency separations between E_(2g)(Γ)and A_(1g)(Γ)modes of MoS_(2) and WS_(2) in the twisted heterostructures varying with twist angle correlate with the interlayer mechanical coupling,essentially originating from the spacing-related repulsion between sulfur atoms.Moreover,the opposite shift behaviors and broadening of A_(1g)(Γ)modes caused by charge transfer are also observed in the twisted heterostructures.The calculated interlayer distances and band alignment of twisted WS_(2)/MoS_(2) through density functional theory further evidence our interpretations on the roles of the interlayer mechanical coupling and charge transfer in variations of Raman features.Such understanding and controlling of interlayer interaction through the stacking orientation are significant for future optoelectronic device design based on the newly emerged 2D heterostructures.展开更多
Dissolution of lithium cobalt oxide(LCO)is the key step for the recovery of valuable metals(e.g.,Co and Li)from spent LCO-based lithium-ion batteries(LIBs).However,the dissolution process of LCO either needs toxic sol...Dissolution of lithium cobalt oxide(LCO)is the key step for the recovery of valuable metals(e.g.,Co and Li)from spent LCO-based lithium-ion batteries(LIBs).However,the dissolution process of LCO either needs toxic solvents,and high temperature,or shows low efficiency.Deep eutectic solvents(DESs)are potential green solvents to dissolve LCO.Here,DESs with polyethylene glycol(PEG)as hydrogen bond acceptor and ascorbic acid(AA)as hydrogen bond donor are found to dissolve LCO with 84.2%Co leaching efficiency at 80℃ and 72 h,which is higher than that from the reported references by common DESs.Furthermore,both DESs components(i.e.,PEG and AA)are cheap,biodegradable,and biocompatible.AA could be easily and abundantly extracted from natural fruits or vegetables.It provides a new guide for the green,mild,and efficient dissolution of LCO aiming at sustainable recovery of spent LIBs.展开更多
With the fast development of nanotechnology,reactive engineered nanomaterials(ENMs)are increasingly discharged into the environment,where they interact with environmental components and organisms and thus pose potenti...With the fast development of nanotechnology,reactive engineered nanomaterials(ENMs)are increasingly discharged into the environment,where they interact with environmental components and organisms and thus pose potential risks.The interactions-derived formation of nano-environmental and nano-bio interfaces determines environmental behaviors and biological effects of ENMs,and ubiquitous dissolved organic matter(DOM)is bound to impact the interfacial interactions and the resulted environmental risks.Herein,we systematically investigated adsorptive interactions between ENMs and various DOM representatives,and thereby demonstrated the effects of DOM on the aqueous suspension/aggregation,mobility in porous media,adsorption of contaminants,transformation,and biological accumulation and toxicity of ENMs.Overall,we conclude that natural DOM can in general expand environmental distribution of ENMs while limit their toxicity to organisms.展开更多
Substrates provide the necessary support for scientific explorations of numerous promising features and exciting potential applications in two-dimensional (2D) transition metal dichalcogenides (TMDs). To utilize subst...Substrates provide the necessary support for scientific explorations of numerous promising features and exciting potential applications in two-dimensional (2D) transition metal dichalcogenides (TMDs). To utilize substrate engineering to alter the properties of 2D TMDs and avoid introducing unwanted adverse effects, various experimental techniques, such as high-frequency Raman spectroscopy, have been used to understand the interactions between 2D TMDs and substrates. However, sample-substrate interaction in 2D TMDs is not yet fully understood due to the lack of systematic studies by techniques that are sensitive to 2D TMD-substrate interaction. This work systematically investigates the interaction between tungsten disulfide (WS_(2)) monolayers and substrates by low-frequency Raman spectroscopy, which is very sensitive to WS_(2)-substrate interaction. Strong coupling with substrates is clearly revealed in chemical vapor deposition (CVD)-grown monolayer WS_(2) by its low-wavenumber interface mode. It is demonstrated that the enhanced sample-substrate interaction leads to tensile strain on monolayer WS_(2), which is induced during the cooling process of CVD growth and could be released for monolayer WS_(2) sample after transfer or fabricated by an annealing-free method such as mechanical exfoliation. These results not only suggest the effectiveness of low-frequency Raman spectroscopy for probing sample-substrate interactions in 2D TMDs, but also provide guidance for the design of high-performance devices with the desired sample-substrate coupling strength based on 2D TMDs.展开更多
The second example of tetravalent plutonium carboxyl-based organic framework,^(242)Pu(OH)[PO[(C_(6)H_(4))COO]_(3)]·H_(2)O,termed as PuTPO(TPO=tris(4-carboxylphenyl)-phosphineoxide),was reported in this work.A ser...The second example of tetravalent plutonium carboxyl-based organic framework,^(242)Pu(OH)[PO[(C_(6)H_(4))COO]_(3)]·H_(2)O,termed as PuTPO(TPO=tris(4-carboxylphenyl)-phosphineoxide),was reported in this work.A series of characterizations of PuTPO,such as X-ray crystallography and solid-state UV-Vis-NIR spectroscopy,were carried out to expatiate its structure and physicochemical properties.PuTPO is constructed by dimers of the plutonium-oxygen subunit of[Pu_(2)O_(16)].Characteristic peaks located at approximately 1100 nm can be considered to be the fingerprint peaks of tetravalent plutonium.While PuTPO can maintain high crystallinity within several months after synthesis,it exhibits a radiation-induced swelling effect probed by the expansion of cell parameter of b axis after self-irradiation fromα-decay of ^(242)Pu.This result enriches the inventory of tetravalent plutonium compounds and provides an insight into the irradiation resistance of metal-organic frameworks.展开更多
We reported the synthesis,single crystal structure,and solid-state UV-Vis-NIR spectroscopy of a new transplutonium metal-organic framework(MOFs),Am(H_(2)O)[PO[(C6H4)COO]_(3)],denoted as AmTPO(TPO=tris(4-carboxylphenyl...We reported the synthesis,single crystal structure,and solid-state UV-Vis-NIR spectroscopy of a new transplutonium metal-organic framework(MOFs),Am(H_(2)O)[PO[(C6H4)COO]_(3)],denoted as AmTPO(TPO=tris(4-carboxylphenyl)-phosphineoxide).AmTPO forms a three-dimensional metal-organic framework structure with americium dimers as the secondary building unit.Clear 5f→5f transi-tions attributed to trivalent americium was observed in the absorption spectrum of AmTPO ranging from 300 to 1200 nm.Notably,AmTPO can maintain the crystallinity with no observable structural degradation within several months after being synthesized,re-vealing a long-term radiation resistance of this structure and the potential application of MOFs as a platform for nuclear waste dis-posal.展开更多
Open metal site(OMS)seated in a luminescent lanthanide(Ln)metal center offers an opportunity for rationally tuning the spectroscopic behavior of lanthanide-organic frameworks aiming for a wide range of sensing applica...Open metal site(OMS)seated in a luminescent lanthanide(Ln)metal center offers an opportunity for rationally tuning the spectroscopic behavior of lanthanide-organic frameworks aiming for a wide range of sensing applications.However,given the spherical nature of common coordination geometries of trivalent lanthanides and the generally strong Ln–O bonds,the lanthanide based OMS is rarely reported and difficult to be functionalized.We report here a unique europium-organic framework containing abundant quasi-OMS that is protected by an abnormal weak Eu–O bond.These quasi-OMSs offer reversible direct binding sites for water molecules probed by X-ray crystallography,leading to sensitive,visible,and ratiometric luminescent sensing toward humidity and water content in organic solvents.The specific recognition of water based on quasi-luminescentOMSs gives rise to a superior water detection limit down to 0.0003%v/v,which is one order of magnitude lower than that of Karl Fischer method.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107284 and 22078177)the Postdoctoral Fellowship Program of CPSF(No.GZB20240410)。
文摘Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,resulting in smaller homologous compounds.Due to the lack of standard substances for debromination products,the in-depth study of DBDPE environmental geochemical behavior through debromination conversion has been hindered.Therefore,based on DBDPE photodegradation experiment,this study first analyzed and identified the brominated products of DBDPE using high-performance liquid chromatography-atmospheric pressure photoionization-time of flight mass spectrometry(HPLC-APPI-TOF/MS).Four debromination products-nonabromodiphenyl ethane(nonaBDPE),octabromodiphenyl ethane(octa-BDPE),heptabromodiphenyl ethane(hepta-BDPE)and hexabromodiphenyl ethane(hexa-BDPE)are identified based on the characteristic ion peak of[M-Br+O]^(-) in negative ion mode.Subsequently,using methanol as the mobile phase,four debromination products of DBDPE were separated and purified with a semi-preparative high-performance liquid chromatography(SP-HPLC)system equipped with an Agilent Zorbax Eclipse PAH column(4.6 mm×250 mm,5μm).The first-time acquisition of hexa-BDPE(60.00μg),octa-BDPE(19.40μg),hepta-BDPE(31.20μg)and octa-BDPE(isomer,45.20μg)with purity exceeding 90%has been achieved.Among them,the purity of one hepta-BDPE monomer is as high as 98.91%.This study indicates that based on photodegradation experiments,the combination of HPLC-APPI-TOF/MS and SP-HPLC techniques can rapidly identify and prepare DBDPE debrominated products.This approach meets the requirements for preliminary research on the pollution characteristics of DBDPE debrominated compounds and offers a feasible solution for the preparation of standard reference materials for emerging pollutants.
基金supported by the National Natural Science Foundation of China under grant 61402160Hunan Provincial Natural Science Foundation of China under grant 2016JJ3043Open Funding for Universities in Hunan Province under grant 14K023
文摘In this paper, we consider the problems of data sharing between multiple distrusted authorities. Prior solutions rely on trusted third parties such as CAs, or are susceptible to collusion between malicious authorities, which can comprise the security of honest ones. In this paper, we propose a new multi-authority data sharing scheme - Decen- tralized Multi-Authority ABE （DMA）, which is derived from CP-ABE that is resilient to these types of misbehavior. Our system distin- guishes between a data owner （DO） principal and attribute authorities （AAs）： the DO owns the data but allows AAs to arbitrate access by providing attribute labels to users. The data is protected by policy encryption over these attributes. Unlike prior systems, attributes generated by AAs are not user-specific, and neither is the system susceptible to collusion between users who try to escalate their access by sharing keys. We prove our scherne correct under the Decisional Bilinear Diffie-Hellman （DBDH） assumption; we also include a com- plete end-to-end implementation that demon- strates the practical efficacy of our technique.
基金supported by the National Natural Science Foundation of China(Grant No.21627802)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB17000000).
文摘A novel bidirectional remotely controlled device for static and dynamic compression/decompression using diamond anvil cells(DACs)has been developed that can control pressure in an accurate and consistent manner.Electromechanical piezoelectric actuators are applied to a conventional DAC,allowing applications under a variety of pressure conditions.Using this static and dynamic DAC(s-dDAC),it is possible to addresses the poorly studied experimental regime lying between purely static and purely dynamic studies.The s-dDAC,driven by three piezoelectric actuators,can be combined with a time-resolved spectral measurement system and high-speed imaging device to study the structural changes,chemical reactions,and properties of materials under extreme conditions.The maximum compression/decompression rate or pressure range highly depends on the culet size of the anvil,and a higher compression rate and wider pressure range can be realized in a DAC with smaller anvil culet.With our s-dDAC,we have been able to achieve the highest compression rate to date with a 300μm culet anvil:48 TPa/s.An overview of a variety of experimental measurements possible with our device is presented.
基金supported by the National Key R & D Program of China (No. 2020YFC2201100)the National Key R & D Program for Intergovernmental International Scientific and Technological Innovation Cooperation, China (No. 2021YFE0116000)+5 种基金the National Natural Science Foundation of China (Nos. 12175032, 12102082, 12275044, 12211530449)the Fundamental Research Funds for the Central Universities of China (Nos. DUT21GJ206 and DUT22QN232)the S & T Program of Hebei, China (Nos. YCYZ202201, 216Z1901G and 206Z1902G)the S & T Innovation Program of Hebei, China (Nos. SJMYF2022X18 and SJMYF2022X06)the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology, China (No. Lab ASP-2020-06)the Funded by Science and Technology Project of Hebei Education Department, China (No. ZC2023144)
文摘In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element Particle-In-Cell Monte-Carlo-Collision(IFE-PIC-MCC)method and the grid erosion evaluation model.The transport process of beam ions and Charge Exchange(CEX)ions in the grid system,and the characteristics and mechanisms of the aperture barrel erosion under extreme erosion conditions(i.e.the cylindrical erosion and chamfer erosion)were systematically studied.Thanks to the advantage of the IFE method for dealing with complex boundaries in structured mesh,the aperture barrel erosion morphology of the accelerator grid is reconstructed accurately based on the experimental results.The results show that,with the evolution of working conditions,the mechanism of the aperture barrel erosion changes significantly,which relies heavily on the accelerator grid morphology.The change of the accelerator grid aperture barrel morphology has a significant effect on the behavior of CEX ions,and only affects the local electric field distribution,but has no effect on the upstream plasma sheath.As the erosion progresses,the erosion position moves downstream along the grid aperture axis direction,and the erosion range becomes narrower.Regardless of the erosion phase,the erosion rate of the CEX ions located downstream of the decelerator grid is the largest.The erosion rate is related to the mean incident energy and angle,and their variation is closely related to the position and trajectory of CEXions.
文摘Objective To investigate N-myc downstream-regulated gene 2(NDRG2) expression in ovarian cancer cells and its potential usefulness as a diagnostic marker and/or target for therapeutic intervention.Methods Human NDRG2 L/S gene was obtained by revers-transcription polymerase chain reaction(RT-PCR). Sequence analysis confirmed the identity of NDRG2 L/S gene, which was then inserted into a eukaryotic vector p LNCX2, which was in turn transfected into NDRG2 gene-negative HO-8910 cells. Flow cytometry(FCM) and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assay were conducted to determine the proliferation rate of HO-8910 cells. Cisplatin resistance of HO-8910 cells transfected with p LNCX2-NDRG2 L/S was evaluated by FCM. Tumors were generated in female nude mice by subcutaneous injection of HO-8910 cells.Results NDRG2 gene was isolated and its expression vector was successfully constructed. NDRG2 expression positively correlated with the proliferation of HO-8910 cells. NDRG2 L/S promoted tumorigenicity in HO-8910 cells.Conclusion The present study identified a novel function of NDRG2 L/S gene and demonstrated its involvement in the promotion of ovarian cancer cell proliferation and enhancement of cisplatin resistance in HO-8910 cells. Future studies are warranted to determine the relationship between NDRG2 upregulation and ovarian cancer progression.
基金support by the National Natural Science Foundation of China(51802269,21773138)Fundamental Research Funds for the Central Universities(XDJK2019AA002)+1 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2018027)the innovation platform for academicians of Hainan province.
文摘Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LD21B070001)。
文摘1Introduction Due to the easy loss and decomposition of traditional chemical pesticides,their repeated application in agriculture results in serious environmental risks to the surrounding environment and organisms.Controlledrelease nanopesticides are attracting attention as a promising technology in agriculture due to their unique structure and effects(e.g.,nano-size scale,interfacial effects,and effective insecticidal time)(An et al.,2022).Their application could improve insecticidal efficacies,decrease usage amounts,and reduce the potential environmental impacts of chemical pesticides.
文摘Citrus blue mold. is an important disease of Citrus postharvest storage and transportation, and a major factor affecting the long-term storage of citrus. The pathogens, harm symptoms as well as the infection circulation of Citrus blue mold were introduced, followed by a summary of the progress on the biological control of Citrus blue mold in recent years, with the aim to provide references for the prevention and control of Citrus blue mold.
文摘Qingshu 9 was approved and formally named as a new potato variety by Qinghai Crop Variety Approval Committee in December 2006. It has outstanding features of high quality, high yield, drought resistance, and disease resistance. Hanzhong Institute of Agricultural Sciences introduced Qingshu 9 from Dingxi County in Gansu Province in 2010. Through years of experiments and demonstrations, the average yield of Qingshu can reach up to 53.14 t/hm^2 with the maximum yield to 63.77 t/hm^2.
基金This work is supported by the Singapore National Research Foundation NRF RF Award No. NRFRF2010- 07, MOE Tier 2 MOE2012-T2-2-049, A＇Star SERC PSF grant No. 1321202101, and MOE Tier 1 MOE2013- T1-2-235. W. Huang acknowledges the support of the National Basic Research Program of China （973 Program） （No. 2015CB932200）, the National Natural Science Foundation of China （NSFC） （Grant Nos. 21144004, 20974046, 21101095, 21003076, 20774043, 51173081, 50428303, 61136003, and 50428303）, the Ministry of Education of China （No. IRT1148）, the NSF of Jiangsu Province （Grant Nos. SBK201122680, 11KJB510017, BK2008053, 11KJB510017, BK2009025, 10KJB510013, and BZ2010043）, and NUPT （Nos. NY210030 and NY211022）. J. R Wang is grateful for the NSFC （No. 11474164）, NSF of Jiangsu province （No. BK20131413）, and the Jiangsu Specially-Appointed Professor program. Y. L. Wang thanks Luqing Wang, Dr. Xiaolong Zou, and Dr. Alex Kutana for the constructive discussion.
文摘In situ strain photoluminescence （PL） and Raman spectroscopy have been employed to exploit the evolutions of the electronic band structure and lattice vibrational responses of chemical vapor deposition （CVD）-grown monolayer tungsten disulphide （WS2） under uniaxial tensile strain. Observable broadening and appearance of an extra small feature at the longer-wavelength side shoulder of the PL peak occur under 2.5% strain, which could indicate the direct-indirect bandgap transition and is further confirmed by our density-functional-theory calculations. As the strain increases further, the spectral weight of the indirect transition gradually increases. Over the entire strain range, with the increase of the strain, the light emissions corresponding to each optical transition, such as the direct bandgap transition （K-K） and indirect bandgap transition （F-K, ≥2.5%）, exhibit a monotonous linear redshift. In addition, the binding energy of the indirect transition is found to be larger than that of the direct transition, and the slight lowering of the trion dissociation energy with increasing strain is observed. The strain was used to modulate not only the electronic band structure but also the lattice vibrations. The softening and splitting of the in-plane E＇ mode is observed under uniaxial tensile strain, and polarization-dependent Raman spectroscopy confirms the observed zigzag-oriented edge of WS2 grown by CVD in previous studies. These findings enrich our understanding of the strained states of monolayer transition-metal dichalcogenide （TMD） materials and lay a foundation for developing applications exploiting their strain-dependent optical properties, including the strain detection and light-emission modulation of such emerging two-dimensional TMDs.
文摘We report the thermal conductivities of monolayer （1L） and bilayer （2L） WS2 grown by chemical vapor deposition （CVD）, which are determined by use of temperature and excitation dependences of E2g^1 and A1g Raman modes. The first-order temperature coefficients of E2g^1 and Alg modes in both supported and suspended WS2 layers were extracted. The frequency shift of the A3g mode with temperature is larger than that of the E1 mode for 1L-WS2, which is 2g attributed to stronger electron-phonon coupling for the A1g mode than that for the E12g mode. Moreover, by use of the shift of the phonon mode induced by laser heating, the thermal conductivities at room temperature were estimated to be 32 and 53 W/（m.K） for 1L- and 2L-WS2, respectively. Our results provide fundamental information about the thermal properties of WS2 layers, which is crucial for developing applications of atomically-thin WS2 devices.
文摘Black phosphorus （BP） is a good candidate for studying strain effects on two- dimensional （2D） materials beyond graphene and transition-metal dichalcogenides. This is because of its particular ability to sustain high strain and remarkably anisotropic mechanical properties resulting from its unique puckered structure. We here investigate the dependence of lattice vibrational frequencies on cry- stallographic orientations in uniaxially strained few-layer BP by in-situ strained Raman spectroscopy. The out-of-plane A1 mode is sensitive to uniaxial strain along the near-armchair direction whereas the in-plane B2g and A2 modes are sensitive to strain in the near-zigzag direction. For uniaxial strains applied away from these directions, all three phonon modes are linearly redshifted. Our experimental observation is explained by the anisotropic influence of uniaxial tensile strain on structural properties of BP using density functional theory. This study demonstrates the possibility of selective tuning of in-plane and out-of-plane phonon modes in BP by uniaxial strain and makes strain engineering a promising avenue for extensively modulating the optical and mechanical properties of 2D materials.
基金This work was mainly supported by the National Key R&D Program of China(Grant No.2018YFA0703700)the Ministry of Education,Singapore,MOE Tier 1 RG93/19,NRF-CRP-21-2018-0007,MOE2018-T2-2-072,and MOE2019T2-1-004+11 种基金C.X.C.also thanks the support of the National Natural Science Foundation of China(Grant No.61774040)the Shanghai Municipal Science and Technology Commission(Grant No.18JC1410300)the Fudan University-CIOMP Joint Fund(Grant No.FC2018-002)the National Young 1000 Talent Plan of China,and the Shanghai Municipal Natural Science Foundation(No.16ZR1402500)J.Z.S.appreciates the support of the Fundamental Research Funds for the Central Universities of ChinaNational Natural Science Foundation of China under Grant No.61904151Natural Science Foundation of Shaanxi under Grant No.2020JM-108the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-020)Z.L.acknowledges the support of MOE Tier 1 grant RG164/15,Tier 2 grant MOE2016-T2-2-153,and MOE2015-T2-2-007Singapore National Research Foundation under NRF award No.NRF-NRFF2013-08W.H.Y.acknowledges the support of the National Natural Science Foundations of China(Grant No.61704040)This research was also supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LGG19F040003).
文摘Twisted van der Waals homo-and hetero-structures have aroused great attentions due to their unique physical properties,providing a new platform to explore the novel two-dimensional(2D)condensed matter physics.The robust dependence of phonon vibrations and electronic band structures on the twist angle has been intensively observed in transition metal dichalcogenide(TMD)homo-structures.However,the effects of twist angle on the lattice vibrational properties in the TMD heterostructures have not caused enough attention.Here,we report the distinct evolutions of Raman scattering and the underlying interlayer interactions in the twisted WS_(2)/MoS_(2) heterostructures.The shifts and linewidths of E_(2g)(Γ)and A_(1g)(Γ)phonon modes are found to be twist angle dependent.In particular,analogous to that of the twisted TMD homostructures,the frequency separations between E_(2g)(Γ)and A_(1g)(Γ)modes of MoS_(2) and WS_(2) in the twisted heterostructures varying with twist angle correlate with the interlayer mechanical coupling,essentially originating from the spacing-related repulsion between sulfur atoms.Moreover,the opposite shift behaviors and broadening of A_(1g)(Γ)modes caused by charge transfer are also observed in the twisted heterostructures.The calculated interlayer distances and band alignment of twisted WS_(2)/MoS_(2) through density functional theory further evidence our interpretations on the roles of the interlayer mechanical coupling and charge transfer in variations of Raman features.Such understanding and controlling of interlayer interaction through the stacking orientation are significant for future optoelectronic device design based on the newly emerged 2D heterostructures.
基金This work was supported by the National Natural Science Foundation of China(22103030)Open Fund of Hebei Biomass Carbon Materials and Application Technology Innovation Center(SG2021003)Special Project for the Cultivation of Scientific and Technological Innovation Ability of College and Middle School Students in Hebei Province(22E50480D).
文摘Dissolution of lithium cobalt oxide(LCO)is the key step for the recovery of valuable metals(e.g.,Co and Li)from spent LCO-based lithium-ion batteries(LIBs).However,the dissolution process of LCO either needs toxic solvents,and high temperature,or shows low efficiency.Deep eutectic solvents(DESs)are potential green solvents to dissolve LCO.Here,DESs with polyethylene glycol(PEG)as hydrogen bond acceptor and ascorbic acid(AA)as hydrogen bond donor are found to dissolve LCO with 84.2%Co leaching efficiency at 80℃ and 72 h,which is higher than that from the reported references by common DESs.Furthermore,both DESs components(i.e.,PEG and AA)are cheap,biodegradable,and biocompatible.AA could be easily and abundantly extracted from natural fruits or vegetables.It provides a new guide for the green,mild,and efficient dissolution of LCO aiming at sustainable recovery of spent LIBs.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0207003)the National Natural Science Foundation of China(21525728 and 21621005).
文摘With the fast development of nanotechnology,reactive engineered nanomaterials(ENMs)are increasingly discharged into the environment,where they interact with environmental components and organisms and thus pose potential risks.The interactions-derived formation of nano-environmental and nano-bio interfaces determines environmental behaviors and biological effects of ENMs,and ubiquitous dissolved organic matter(DOM)is bound to impact the interfacial interactions and the resulted environmental risks.Herein,we systematically investigated adsorptive interactions between ENMs and various DOM representatives,and thereby demonstrated the effects of DOM on the aqueous suspension/aggregation,mobility in porous media,adsorption of contaminants,transformation,and biological accumulation and toxicity of ENMs.Overall,we conclude that natural DOM can in general expand environmental distribution of ENMs while limit their toxicity to organisms.
基金This work is supported by the National Natural Science Foundation of China(Nos.62004197 and 61774040)the Ministry of Education of Singapore(No.MOE2019-T2-1-004)+5 种基金the Singapore National Research Foundation under the Competitive Research Programs(No.NRF-CRP-21-2018-0007)the National Key R&D Program of China(No.2018YFA0703700)the National Young 1000 Talent Plan of China,the Shanghai Municipal Natural Science Foundation(No.20ZR1403200)the Shanghai Municipal Science and Technology Commission(No.18JC1410300)the Fudan University-CIOMP Joint Fund(No.FC2018-002)the Natural Science Foundation of Liaoning Province,China(Nos.2019-BS-243 and 2019-MS-320).
文摘Substrates provide the necessary support for scientific explorations of numerous promising features and exciting potential applications in two-dimensional (2D) transition metal dichalcogenides (TMDs). To utilize substrate engineering to alter the properties of 2D TMDs and avoid introducing unwanted adverse effects, various experimental techniques, such as high-frequency Raman spectroscopy, have been used to understand the interactions between 2D TMDs and substrates. However, sample-substrate interaction in 2D TMDs is not yet fully understood due to the lack of systematic studies by techniques that are sensitive to 2D TMD-substrate interaction. This work systematically investigates the interaction between tungsten disulfide (WS_(2)) monolayers and substrates by low-frequency Raman spectroscopy, which is very sensitive to WS_(2)-substrate interaction. Strong coupling with substrates is clearly revealed in chemical vapor deposition (CVD)-grown monolayer WS_(2) by its low-wavenumber interface mode. It is demonstrated that the enhanced sample-substrate interaction leads to tensile strain on monolayer WS_(2), which is induced during the cooling process of CVD growth and could be released for monolayer WS_(2) sample after transfer or fabricated by an annealing-free method such as mechanical exfoliation. These results not only suggest the effectiveness of low-frequency Raman spectroscopy for probing sample-substrate interactions in 2D TMDs, but also provide guidance for the design of high-performance devices with the desired sample-substrate coupling strength based on 2D TMDs.
基金supported by grants from the National Natural Science Foundation of China(21825601,21790374,21906113,21727801)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The second example of tetravalent plutonium carboxyl-based organic framework,^(242)Pu(OH)[PO[(C_(6)H_(4))COO]_(3)]·H_(2)O,termed as PuTPO(TPO=tris(4-carboxylphenyl)-phosphineoxide),was reported in this work.A series of characterizations of PuTPO,such as X-ray crystallography and solid-state UV-Vis-NIR spectroscopy,were carried out to expatiate its structure and physicochemical properties.PuTPO is constructed by dimers of the plutonium-oxygen subunit of[Pu_(2)O_(16)].Characteristic peaks located at approximately 1100 nm can be considered to be the fingerprint peaks of tetravalent plutonium.While PuTPO can maintain high crystallinity within several months after synthesis,it exhibits a radiation-induced swelling effect probed by the expansion of cell parameter of b axis after self-irradiation fromα-decay of ^(242)Pu.This result enriches the inventory of tetravalent plutonium compounds and provides an insight into the irradiation resistance of metal-organic frameworks.
基金supported by grants from the National Natural Science Foundation of China(21825601,21790374,21906113,21727801)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘We reported the synthesis,single crystal structure,and solid-state UV-Vis-NIR spectroscopy of a new transplutonium metal-organic framework(MOFs),Am(H_(2)O)[PO[(C6H4)COO]_(3)],denoted as AmTPO(TPO=tris(4-carboxylphenyl)-phosphineoxide).AmTPO forms a three-dimensional metal-organic framework structure with americium dimers as the secondary building unit.Clear 5f→5f transi-tions attributed to trivalent americium was observed in the absorption spectrum of AmTPO ranging from 300 to 1200 nm.Notably,AmTPO can maintain the crystallinity with no observable structural degradation within several months after being synthesized,re-vealing a long-term radiation resistance of this structure and the potential application of MOFs as a platform for nuclear waste dis-posal.
基金the Young Taishan Scholars Program(tsqn201909082,tsqn201909087)the National Natural Science Foundation of China(21825601,21790370,21790374)+1 种基金the Top Discipline in Materials Science of Shandong Provincethe Natural Science Foundation of Shandong Province(ZR201910290031)。
文摘Open metal site(OMS)seated in a luminescent lanthanide(Ln)metal center offers an opportunity for rationally tuning the spectroscopic behavior of lanthanide-organic frameworks aiming for a wide range of sensing applications.However,given the spherical nature of common coordination geometries of trivalent lanthanides and the generally strong Ln–O bonds,the lanthanide based OMS is rarely reported and difficult to be functionalized.We report here a unique europium-organic framework containing abundant quasi-OMS that is protected by an abnormal weak Eu–O bond.These quasi-OMSs offer reversible direct binding sites for water molecules probed by X-ray crystallography,leading to sensitive,visible,and ratiometric luminescent sensing toward humidity and water content in organic solvents.The specific recognition of water based on quasi-luminescentOMSs gives rise to a superior water detection limit down to 0.0003%v/v,which is one order of magnitude lower than that of Karl Fischer method.
