Mangrove （Sonneratia spp.） could be found at Waai seashore, Ambon island. The remainder of the mangrove stem will be decayed and become the waste product. Some indigenous bacteria species that live in the decayed ma...Mangrove （Sonneratia spp.） could be found at Waai seashore, Ambon island. The remainder of the mangrove stem will be decayed and become the waste product. Some indigenous bacteria species that live in the decayed mangrove stem waste product have cellulolytic and amylolytic characters. This research was done to： （1） identify and determine the cellulolytic bacteria species; （2） identify and determine the amylolytic bacteria species; （3） determine the cellulolytic bacteria species that have the highest cellulase activity; （4） determine the amylolytic bacteria species that have the highest amylase activity. This research was conducted at the Microbiology Laboratory, Department of Biology, State University of Malang, Microbiology Laboratory, Faculty of Medicine, Brawijaya University and Chemistry Laboratory, Muhammadiyah Malang University. In the experiment, 25 g sample were grinded and diluted in 225 mL nutrient broth to get 101 suspension. Then the suspension was diluted gradually until 101~. The suspension was inoculated on nutrient agar medium with 0.1 mL each, and incubated in 37 ~C during 24 h. Each bacteria colony was isolated and identified to know whether it was cellulolytic or amylolytic bacteria. Afterward, the cellulase activity as well as the amylase activity was analyzed. The research results show that： （1） there are four cellulolytic bacteria species, i.e., Micrococcus luteus, Bacillus pumilus, Planococcus citreus and Bacillus cereus; （2） there are four amylolytic bacteria species, i.e., Bacillus firmus, Nitrobacter sp., Bacillus mycoides and Pseudomonas aeruginosa; （3） Bacillus cereus has the highest cellulase activity; （4） Nitrobacter sp. has the highest amylase activity.展开更多
This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentia...This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentially increased.This is based on the fact that although the cooking yield of decayed spruce material which has been sorted according to these new recommendations is somewhat lower and Kappa number higher than those of sound wood material,the greatest part of the decayed stem(the outer part of the stem)contains long-fiber wood material which produces pulp of good quality.Therefore,large-diameter spruce logs can also be separately used,for example,in the manufacture of reinforcement pulp.展开更多
Viral infections play a crucial role in marine biogeochemical cycles,by regulating bacterial mortality and mediating nutrient and carbon fluxes.However,despite of their ecological significance,existing climate change ...Viral infections play a crucial role in marine biogeochemical cycles,by regulating bacterial mortality and mediating nutrient and carbon fluxes.However,despite of their ecological significance,existing climate change models generally fail to incorporate virus-mediated ecological processes due to the current limited understanding of marine viral dynamics under global warming.While numerous studies have explored the effect of warming for viral decay and production,how temperature regulates the total abundance of marine viruses remains unclear.In this study,we conducted year-round measurements of viral production and decay rates in Qingdao's coastal waters,with additional experimental warming treatments.The result showed that under in-situ temperature,the viral decay and production rate displayed distinct seasonal variations.With the exception of summer,elevated temperature stimulated both viral decay rate and production rate,and further improved the net viral production rate.While in summer,the net viral production rate turned negative,implying divergent threshold viral decay and viral production rate on warming.Our study deepens the understanding of the effect of global warming on marine viruses and provides scientific data for climate change models.展开更多
Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH...Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH18,and DH29)with distinct Zn and PA profiles were used to evaluate the effects of varying degrees of milling(DOM)on Zn bioavailability.Results showed DOM followed a double-exponential decay pattern(R^(2)>0.99)with milling time,varying among the four DH lines under identical milling conditions.As DOM increased,Zn,PA,and phosphorus(P)concentrations decreased progressively.展开更多
We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-...We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.展开更多
Making full use of the operator ordering method and the integration within ordered products,we obtain the analytical evolution law of a general quadratic state in the amplitude decay channel,and find that it is determ...Making full use of the operator ordering method and the integration within ordered products,we obtain the analytical evolution law of a general quadratic state in the amplitude decay channel,and find that it is determined not only by the decay rate of the amplitude decay channel but also by the coefficients of the initial quadratic state.Further,the quantum statistical properties of the initial quadratic state for amplitude decay are investigated via its average photon number and photon-counting distribution,and its Wigner distribution function evolution is discussed in detail.展开更多
Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-...Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-mediated e–h recombination the dominant decay pathway.In this work,nonradiative e–h recombination within excitons in monolayer MoS_(2) is investigated using first-principles simulations that combine nonadiabatic molecular dynamics with GW and real-time Bethe–Salpeter equation(BSE)propagation.A two-step process is identified:rapid intervalley redistribution induced by exchange interaction,followed by slower phonon-assisted recombination facilitated by exciton binding.By selectively removing the screened Coulomb and exchange terms from the BSE Hamiltonian,their respective contributions are disentangled—exchange interaction is found to increase the number of accessible recombination pathways,while binding reduces the excitation energy and enhances nonradiative decay.A reduction in recombination lifetime by over an order of magnitude is observed due to the excitonic many-body effects.These findings provide microscopic insights for understanding and tuning exciton lifetimes in 2D transition-metal dichalcogenides.展开更多
The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,an...The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.展开更多
Owing to the inherent limitation of the internal pulse ionization chamber within the AlphaGUARD PQ2000 radon monitor,that is,its inability to discriminate the energy levels of α particles,the ingress of^(220)Rn from ...Owing to the inherent limitation of the internal pulse ionization chamber within the AlphaGUARD PQ2000 radon monitor,that is,its inability to discriminate the energy levels of α particles,the ingress of^(220)Rn from the surrounding environment,along with its decay progeny,poses a substantive challenge in accurately determining the^(222)Rn concentration in the measurement outcomes.Among these,the protracted influence primarily stems from the two enduring decay progenies,namely^(212)Pb with a half-life of 10.64 h and^(212)Bi with a half-life of 60.54 min.This study explored the influence of^(220)Rn progeny on the measurement results of an AlphaGUARD PQ2000 radon monitor by developing a theoretical calculation model.The response coefficient related to the residual^(220)Rn progeny within the AlphaGUARD PQ2000 radon monitor was experimentally validated.In addition,this study investigated the effects of temperature and wind speed on the sensitivity of the instrument to^(220)Rn gas.The research findings revealed commendable agreement between the experimentally measured response coefficients of the residual^(220)Rn progeny and the corresponding values derived from the theoretical model.Notably,both the response coefficients of the AlphaGUARD PQ2000 radon monitor to^(220)Rn gas and its internal residual^(220)Rn progeny increased with elevated temperatures and increased wind speeds,providing a reference for correcting the impact of^(220)Rn and its progeny on the measurement results of^(222)Rn concentration obtained using the AlphaGUARD PQ2000 radon monitor.展开更多
Water level fluctuations in the reservoir deteriorate soils and rocks on the bank landslides by drying-wetting(D-W)cycles,which results in a significant decrease in mechanical properties.A comprehensive understanding ...Water level fluctuations in the reservoir deteriorate soils and rocks on the bank landslides by drying-wetting(D-W)cycles,which results in a significant decrease in mechanical properties.A comprehensive understanding of deterioration mechanism of sliding-zone soils is of great significance for interpreting the deformation behavior of landslides.However,quantitative investigation on the deterioration characteristics of soils considering the structural evolution under D-W cycles is still limited.Here,we carry out a series of laboratory tests to characterize the multi-scale deterioration of sliding-zone soils and reveal the mechanism of shear strength decay under D-W cycles.Firstly,we describe the micropores into five grades by scanning electron microscope and observe a critical change in porosity after the first three cycles.We categorize the mesoscale cracks into five classes using digital photography and observe a stepwise increase in crack area ratio.Secondly,we propose a shear strength decay model based on fractal theory which is verified by the results of consolidated undrained triaxial tests.Cohesion and friction angle of sliding-zone soils are found to show different decay patterns resulting from the staged evolution of structure.Then,structural deterioration processes including cementation destruction,pores expansion,aggregations decomposition,and clusters assembly are considered to occur to decay the shear strength differently.Finally,a three-stage deterioration mechanism associated with four structural deterioration processes is revealed,which helps to better interpret the intrinsic mechanism of shear strength decay.These findings provide the theoretical basis for the further accurate evaluation of reservoir landslides stability under water level fluctuations.展开更多
The challenge in searching for fundamental symmetry violation.Neutrinoless double-beta(0νββ)decay represents one of the most profound tests of fundamental symmetries in nature.This hypothetical nuclear process,in w...The challenge in searching for fundamental symmetry violation.Neutrinoless double-beta(0νββ)decay represents one of the most profound tests of fundamental symmetries in nature.This hypothetical nuclear process,in which two neutrons simultaneously decay into two protons with the emission of two electrons but no neutrinos,would demonstrate that lepton number is not conserved and confirm that neutrinos are their own antiparticles(Majorana particles).The observation of 0νββdecay would provide crucial insights into the absolute neutrino mass scale and could illuminate the origin of matter-antimatter asymmetry in the universe.展开更多
Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo stru...Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo structure. Beyond the proton dripline, nuclei become unbound, allowing protons to be emitted and giving rise to novel radioactive decay modes. Single-proton radioactivity, a process in which some nuclei with an odd number of protons(Z) decay by ejecting a proton, was discovered several decades ago and has been extensively studied [1, 2].展开更多
In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4...In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP).Herein,a strategy of introducing columnar potassium ions at the Na_(4)site is proposed to address the aforementioned challenge.As a cathode material for sodium-ion batteries,the K_(0.12)Na_(3.88)Fe_(3)(PO_(4))_(2)P_(2)O_(7)/C(K-NFPP)composite enhances the reversibility of Na_(4)extraction.Specifically,the K-NFPP exhibits an initial discharge capacity of 107.8 mAh g^(-1)at a high current density of 5 C,with a capacity retention of 91.4% after 2000 cycles,outperforming the pristine NFPP material(81.1 m Ah g^(-1)and 67.1%).At 5 C,the K-NFPP also retains 81.5% of the reversible capacity at 0.1 C,whereas the NFPP only retains 68.3%.Moreover,the K-NFPP-based full-cell delivers an initial capacity of 110.1 m Ah g^(-1)at 1 C,with a capacity retention of 90% after 100 cycles.It is found that in comparison to K-doping of the Na1,Na2,and Na3 sites,K-doping at the Na4 site effectively optimizes the band gap and stabilizes the crystal structure,thereby reducing lattice changes of FeO_(6)evolution during Na^(+)insertion/extraction.As a result,the introduction of columnar potassium ions significantly enhances the capacity contribution of the Na_(4)site,optimizes reaction kinetics,and effectively mitigates the capacity decay of NFPP cathodes.It is believed that this study offers a new entry point for the application of NFPP in high-voltage sodium storage.展开更多
The validity of the isobaric multiplet mass equation(IMME)is of foundamental importance due to the basic concept of isospin.Recently,a serious breakdown was found in the A=54,T=3,isospin septet,the largest isospin sys...The validity of the isobaric multiplet mass equation(IMME)is of foundamental importance due to the basic concept of isospin.Recently,a serious breakdown was found in the A=54,T=3,isospin septet,the largest isospin system where the validity of IMME have been tested up to now.Inspired by this work,I revist the mass of some isobaric analogue states with the help of recent results from advanced mass measurement experiment.It is found that the IMME holds well in A=50 and 46 isospin septet and the coefficients of IMME also follow the systematic trends.Mass excess value for^(50)Ni and^(46)Fe,is predicted to be-3932(20)keV and 898(67)keV,respectively.展开更多
A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nu...A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nuclei.The digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγdetectors.The system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).Key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for validation.Using the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time information.This detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.展开更多
This paper focuses on the investigation of a hyperbolic Kirchhoff equation with nonlinear damping and higher-order dissipation terms.Initially,the existence and uniqueness of local weak solutions are rigorously establ...This paper focuses on the investigation of a hyperbolic Kirchhoff equation with nonlinear damping and higher-order dissipation terms.Initially,the existence and uniqueness of local weak solutions are rigorously established.Next,within the framework of potential well theory,the classification of solution behaviors,including blow-up and global existence,is systematically analyzed according to the relationships among the exponents of nonlinear source terms.Finally,explicit bounds for the blow-up time and decay estimates for global solutions are presented.展开更多
Wood,recognized as a renewable and environmentally sustainable material,plays a crucial role as an alternative energy resource within the construction industry.However,it is highly susceptible to mold and decay fungi,...Wood,recognized as a renewable and environmentally sustainable material,plays a crucial role as an alternative energy resource within the construction industry.However,it is highly susceptible to mold and decay fungi,which can lead to surface discoloration and potentially compromise the structural integrity of wood.The advancement of nanotechnology has introduced innovative strategies for wood protection,enhancing its performance while imparting additional properties.Various approaches including nanosized metals,polymer nanocomposite and coating treatments are actively being explored in this field.Furthermore,integrating bio-based materials with nanotechnology offers a green and sustainable method for wood preservation.This paper provides an analysis,discussion,and synthesis of the applications of nanotechnology in wood protection along with its antifungal mechanisms,thereby contributing novel insights into the research landscape surrounding this topic.展开更多
Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline el...Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline electrolytes,the electrochemical instability and capacity degradation of VN electrode materials present significant challenges for practical applications.Herein,the capacitance decay mechanism of VN is investigated and a simple strategy to improve cycling stability of VN supercapacitor electrodes is proposed by introducing VO_(4)^(3-)anion in KOH electrolytes.Our results show that the VN electrode is electrochemical stabilization between-1.0and-0.4 V(vs.Hg/Hg O reference electrode)in 1.0 MKOH electrolyte,but demonstrates irreversible oxidation and fast capacitance decay in the potential range of-0.4 to0 V.In situ electrochemical measurements reveal that the capacitance decay of VN from-0.4 to 0 V is ascribed to the irreversible oxidation of vanadium(V)of N–V–O species by oxygen(O)of OH^(-).The as-generated oxidization species are subsequently dissolved into KOH electrolytes,thereby undermining the electrochemical stability of VN.However,this irreversible oxidation process could be hindered by introducing VO_(4)^(3-)in KOH electrolytes.A high volumetric specific capacitance of671.9 F.cm^(-3)(1 A.cm^(-3))and excellent cycling stability(120.3%over 1000 cycles)are achieved for VN nanorod electrode in KOH electrolytes containing VO_(4)^(3-).This study not only elucidates the failure mechanism of VN supercapacitor electrodes in alkaline electrolytes,but also provides new insights into enhancing pseudocapacitive energy storage of VN-based electrode materials.展开更多
Evaluation of damage evolution effects in biodegradable pure Mg was carried out,using transmission electron microscope as surrogate irradiation for high-energy radionuclide β decay in Brachytherapy.Time-dependent qua...Evaluation of damage evolution effects in biodegradable pure Mg was carried out,using transmission electron microscope as surrogate irradiation for high-energy radionuclide β decay in Brachytherapy.Time-dependent quantitative defect production,evolution dynamics,and evolution statistics were revealed in-situ for two prism foils(z=[1.210],[10.10]),in as-received and heat-treated pure Mg,after 300 keV electron irradiation up to 0.468 dpa at R.T.Preferred nucleation of basal-plane interstitial-type 1/6<20.23>loops was confirmed,in addition to a small portion of prism-plane 1/3<11.20>loops.No cavities were found.A higher yield of point defect concentration and a more evident trend of defect coarsening were identified in[1.210]than in[10.10].Pre-existing dislocations(on the orders of 10^(13)−10^(14) m^(−2))in pure Mg resulted in a delay of the first occurrence of visible defects.Defect migration and elastic interactions governed the microstructural evolution of electron irradiation damage in pure Mg,giving rise to events of loop coalescence,growth,and sometimes rotation of habit plane.The influence of incident electron energy can be correlated to the rates of point defect production,and is quantifiable;however,interfered by defect cluster stability,defect mobility,and defect interactions.This forms an important theoretical basis for the application of Mg subjected to MeV-level β-decay radiation in Brachytherapy.The paper concludes with a brief comparison between Mg and conventional Ti casing,outlines the advantages and challenges,and provides reference points for the validation of Mg/Mg-alloys in Brachytherapy seed application.展开更多
The present paper deals with the Cauchy problem to a two-fluid plasma model with unequal viscosities in any dimension N≥2.Employing the precise spectral analysis for the corresponding linearized system,we prove the g...The present paper deals with the Cauchy problem to a two-fluid plasma model with unequal viscosities in any dimension N≥2.Employing the precise spectral analysis for the corresponding linearized system,we prove the global well-posedness provided that the initial data are close to a stable equilibrium state in critical functional framework which is not related to the energy space.Moreover,the optimal decay rates for the constructed global solution are also established.展开更多
文摘Mangrove （Sonneratia spp.） could be found at Waai seashore, Ambon island. The remainder of the mangrove stem will be decayed and become the waste product. Some indigenous bacteria species that live in the decayed mangrove stem waste product have cellulolytic and amylolytic characters. This research was done to： （1） identify and determine the cellulolytic bacteria species; （2） identify and determine the amylolytic bacteria species; （3） determine the cellulolytic bacteria species that have the highest cellulase activity; （4） determine the amylolytic bacteria species that have the highest amylase activity. This research was conducted at the Microbiology Laboratory, Department of Biology, State University of Malang, Microbiology Laboratory, Faculty of Medicine, Brawijaya University and Chemistry Laboratory, Muhammadiyah Malang University. In the experiment, 25 g sample were grinded and diluted in 225 mL nutrient broth to get 101 suspension. Then the suspension was diluted gradually until 101~. The suspension was inoculated on nutrient agar medium with 0.1 mL each, and incubated in 37 ~C during 24 h. Each bacteria colony was isolated and identified to know whether it was cellulolytic or amylolytic bacteria. Afterward, the cellulase activity as well as the amylase activity was analyzed. The research results show that： （1） there are four cellulolytic bacteria species, i.e., Micrococcus luteus, Bacillus pumilus, Planococcus citreus and Bacillus cereus; （2） there are four amylolytic bacteria species, i.e., Bacillus firmus, Nitrobacter sp., Bacillus mycoides and Pseudomonas aeruginosa; （3） Bacillus cereus has the highest cellulase activity; （4） Nitrobacter sp. has the highest amylase activity.
基金The authors wish to thank Mittaportti Oy for the log classification,Metsäteho Oy for the rot determinations,and Western Laboratories Inc.for the pulp strength analyses.
文摘This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentially increased.This is based on the fact that although the cooking yield of decayed spruce material which has been sorted according to these new recommendations is somewhat lower and Kappa number higher than those of sound wood material,the greatest part of the decayed stem(the outer part of the stem)contains long-fiber wood material which produces pulp of good quality.Therefore,large-diameter spruce logs can also be separately used,for example,in the manufacture of reinforcement pulp.
基金supported by the National Natural Science Foundation of China(No.42276108)the Young Scientists Fund of Shandong Provincial Natural Science Foundation(No.ZR2022QD052)。
文摘Viral infections play a crucial role in marine biogeochemical cycles,by regulating bacterial mortality and mediating nutrient and carbon fluxes.However,despite of their ecological significance,existing climate change models generally fail to incorporate virus-mediated ecological processes due to the current limited understanding of marine viral dynamics under global warming.While numerous studies have explored the effect of warming for viral decay and production,how temperature regulates the total abundance of marine viruses remains unclear.In this study,we conducted year-round measurements of viral production and decay rates in Qingdao's coastal waters,with additional experimental warming treatments.The result showed that under in-situ temperature,the viral decay and production rate displayed distinct seasonal variations.With the exception of summer,elevated temperature stimulated both viral decay rate and production rate,and further improved the net viral production rate.While in summer,the net viral production rate turned negative,implying divergent threshold viral decay and viral production rate on warming.Our study deepens the understanding of the effect of global warming on marine viruses and provides scientific data for climate change models.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFD1200702)the Sanya Fanxing Technology Special Program,China(Grant No.2024KJFX023)the Shandong Provincial Key Research and Development Program,China(Grant No.2023LZGCQY018).
文摘Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH18,and DH29)with distinct Zn and PA profiles were used to evaluate the effects of varying degrees of milling(DOM)on Zn bioavailability.Results showed DOM followed a double-exponential decay pattern(R^(2)>0.99)with milling time,varying among the four DH lines under identical milling conditions.As DOM increased,Zn,PA,and phosphorus(P)concentrations decreased progressively.
基金supported in part by the National Key R&D Program of China (Contract Nos.2023YFA1606500,2024YFE0109800,and 2024YFE0110400)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34010000)+5 种基金the Gansu Key Project of Science and Technology (Grant No.23ZDGA014)the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2021B0301030006)the National Natural Science Foundation of China (Grant Nos.12105328,W2412040,12475126,12422507,12035011,12375118,12435008,and W2412043)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-002)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos.2020409 and 2023439)the Russian Science Foundation (Grant No.25-42-00003)。
文摘We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.
文摘Making full use of the operator ordering method and the integration within ordered products,we obtain the analytical evolution law of a general quadratic state in the amplitude decay channel,and find that it is determined not only by the decay rate of the amplitude decay channel but also by the coefficients of the initial quadratic state.Further,the quantum statistical properties of the initial quadratic state for amplitude decay are investigated via its average photon number and photon-counting distribution,and its Wigner distribution function evolution is discussed in detail.
基金supported by the National Key Research and Development Program of China (Grant Nos.2024YFA1409800 for J.Z.and2024YFA1408603 for Q.Z.)the National Natural Science Foundation of China (Grant Nos.12125408,12334004for J.Z.,and 12174363 for Q.Z.)+1 种基金the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0303306 for J.Z.)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450101 for J.Z.)。
文摘Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-mediated e–h recombination the dominant decay pathway.In this work,nonradiative e–h recombination within excitons in monolayer MoS_(2) is investigated using first-principles simulations that combine nonadiabatic molecular dynamics with GW and real-time Bethe–Salpeter equation(BSE)propagation.A two-step process is identified:rapid intervalley redistribution induced by exchange interaction,followed by slower phonon-assisted recombination facilitated by exciton binding.By selectively removing the screened Coulomb and exchange terms from the BSE Hamiltonian,their respective contributions are disentangled—exchange interaction is found to increase the number of accessible recombination pathways,while binding reduces the excitation energy and enhances nonradiative decay.A reduction in recombination lifetime by over an order of magnitude is observed due to the excitonic many-body effects.These findings provide microscopic insights for understanding and tuning exciton lifetimes in 2D transition-metal dichalcogenides.
基金supported by the National Natural Science Foundation of China(Grant No.12172063).
文摘The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.
基金supported by the National Natural Science Foundation of China(No.12175102)Hunan Provincial Natural Science Foundation(No.2022JJ40346)the 2022 Hunan Provincial University Student Innovation and Entrepreneurship Training Program(No.S202210555144).
文摘Owing to the inherent limitation of the internal pulse ionization chamber within the AlphaGUARD PQ2000 radon monitor,that is,its inability to discriminate the energy levels of α particles,the ingress of^(220)Rn from the surrounding environment,along with its decay progeny,poses a substantive challenge in accurately determining the^(222)Rn concentration in the measurement outcomes.Among these,the protracted influence primarily stems from the two enduring decay progenies,namely^(212)Pb with a half-life of 10.64 h and^(212)Bi with a half-life of 60.54 min.This study explored the influence of^(220)Rn progeny on the measurement results of an AlphaGUARD PQ2000 radon monitor by developing a theoretical calculation model.The response coefficient related to the residual^(220)Rn progeny within the AlphaGUARD PQ2000 radon monitor was experimentally validated.In addition,this study investigated the effects of temperature and wind speed on the sensitivity of the instrument to^(220)Rn gas.The research findings revealed commendable agreement between the experimentally measured response coefficients of the residual^(220)Rn progeny and the corresponding values derived from the theoretical model.Notably,both the response coefficients of the AlphaGUARD PQ2000 radon monitor to^(220)Rn gas and its internal residual^(220)Rn progeny increased with elevated temperatures and increased wind speeds,providing a reference for correcting the impact of^(220)Rn and its progeny on the measurement results of^(222)Rn concentration obtained using the AlphaGUARD PQ2000 radon monitor.
基金funding support from the NSFC Key Projects of International Cooperation and Exchanges (Grant No.42020104006)the National Key Research and Development Program of China (Grant No.2023YFC3007001)the National Natural Science Foundation of China (Grant No.42307227).
文摘Water level fluctuations in the reservoir deteriorate soils and rocks on the bank landslides by drying-wetting(D-W)cycles,which results in a significant decrease in mechanical properties.A comprehensive understanding of deterioration mechanism of sliding-zone soils is of great significance for interpreting the deformation behavior of landslides.However,quantitative investigation on the deterioration characteristics of soils considering the structural evolution under D-W cycles is still limited.Here,we carry out a series of laboratory tests to characterize the multi-scale deterioration of sliding-zone soils and reveal the mechanism of shear strength decay under D-W cycles.Firstly,we describe the micropores into five grades by scanning electron microscope and observe a critical change in porosity after the first three cycles.We categorize the mesoscale cracks into five classes using digital photography and observe a stepwise increase in crack area ratio.Secondly,we propose a shear strength decay model based on fractal theory which is verified by the results of consolidated undrained triaxial tests.Cohesion and friction angle of sliding-zone soils are found to show different decay patterns resulting from the staged evolution of structure.Then,structural deterioration processes including cementation destruction,pores expansion,aggregations decomposition,and clusters assembly are considered to occur to decay the shear strength differently.Finally,a three-stage deterioration mechanism associated with four structural deterioration processes is revealed,which helps to better interpret the intrinsic mechanism of shear strength decay.These findings provide the theoretical basis for the further accurate evaluation of reservoir landslides stability under water level fluctuations.
文摘The challenge in searching for fundamental symmetry violation.Neutrinoless double-beta(0νββ)decay represents one of the most profound tests of fundamental symmetries in nature.This hypothetical nuclear process,in which two neutrons simultaneously decay into two protons with the emission of two electrons but no neutrinos,would demonstrate that lepton number is not conserved and confirm that neutrinos are their own antiparticles(Majorana particles).The observation of 0νββdecay would provide crucial insights into the absolute neutrino mass scale and could illuminate the origin of matter-antimatter asymmetry in the universe.
文摘Introduction-Nuclei near and beyond the proton drip line represent a fascinating frontier in the nuclear landscape. Proton-rich nuclei exhibit intriguing phenomena, such as the Thomas-Ehrman shift and proton-halo structure. Beyond the proton dripline, nuclei become unbound, allowing protons to be emitted and giving rise to novel radioactive decay modes. Single-proton radioactivity, a process in which some nuclei with an odd number of protons(Z) decay by ejecting a proton, was discovered several decades ago and has been extensively studied [1, 2].
基金financial support from the National Natural Science Foundation of China(52272237,22279101 and 22172117)the Natural Science Foundation of Shaanxi(2020JC-41 and 2024JC-YBQN-0141)+2 种基金the Scientific Research Program Funded by the Education Department of Shaanxi Provincial Government(22JP056)the S&T Program of Energy Shaanxi Laboratory(ESLB202402)the Foshan Science and Technology Innovation Team Project(1920001004098)。
文摘In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP).Herein,a strategy of introducing columnar potassium ions at the Na_(4)site is proposed to address the aforementioned challenge.As a cathode material for sodium-ion batteries,the K_(0.12)Na_(3.88)Fe_(3)(PO_(4))_(2)P_(2)O_(7)/C(K-NFPP)composite enhances the reversibility of Na_(4)extraction.Specifically,the K-NFPP exhibits an initial discharge capacity of 107.8 mAh g^(-1)at a high current density of 5 C,with a capacity retention of 91.4% after 2000 cycles,outperforming the pristine NFPP material(81.1 m Ah g^(-1)and 67.1%).At 5 C,the K-NFPP also retains 81.5% of the reversible capacity at 0.1 C,whereas the NFPP only retains 68.3%.Moreover,the K-NFPP-based full-cell delivers an initial capacity of 110.1 m Ah g^(-1)at 1 C,with a capacity retention of 90% after 100 cycles.It is found that in comparison to K-doping of the Na1,Na2,and Na3 sites,K-doping at the Na4 site effectively optimizes the band gap and stabilizes the crystal structure,thereby reducing lattice changes of FeO_(6)evolution during Na^(+)insertion/extraction.As a result,the introduction of columnar potassium ions significantly enhances the capacity contribution of the Na_(4)site,optimizes reaction kinetics,and effectively mitigates the capacity decay of NFPP cathodes.It is believed that this study offers a new entry point for the application of NFPP in high-voltage sodium storage.
文摘The validity of the isobaric multiplet mass equation(IMME)is of foundamental importance due to the basic concept of isospin.Recently,a serious breakdown was found in the A=54,T=3,isospin septet,the largest isospin system where the validity of IMME have been tested up to now.Inspired by this work,I revist the mass of some isobaric analogue states with the help of recent results from advanced mass measurement experiment.It is found that the IMME holds well in A=50 and 46 isospin septet and the coefficients of IMME also follow the systematic trends.Mass excess value for^(50)Ni and^(46)Fe,is predicted to be-3932(20)keV and 898(67)keV,respectively.
基金supported by the National Key Research and Development Project,China(No.2023YFA1606404)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34010300)+5 种基金the National Natural Science Foundation of China(Nos.12022501,12105329,12475127)the Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030006)the Research Program of Heavy Ion Science and Technology Key Laboratory,Institute of Modern Physics,Chinese Academy of Sciences(Nos.HIST2024KS04,HIST2024CO04)Longyuan Youth Innovation and Entrepreneurship Talent Project of Gansu Province(No.2024GZT04)State Key Laboratory of Nuclear Physics and Technology,Peking University(No.NPT2023KFY01)the Major Science and Technology Projects in Gansu Province(No.24GD13GA005)。
文摘A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nuclei.The digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγdetectors.The system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).Key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for validation.Using the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time information.This detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.
基金Supported by Shandong Provincial Natural Science Foundation of China(Grant No.ZR2021MA003)。
文摘This paper focuses on the investigation of a hyperbolic Kirchhoff equation with nonlinear damping and higher-order dissipation terms.Initially,the existence and uniqueness of local weak solutions are rigorously established.Next,within the framework of potential well theory,the classification of solution behaviors,including blow-up and global existence,is systematically analyzed according to the relationships among the exponents of nonlinear source terms.Finally,explicit bounds for the blow-up time and decay estimates for global solutions are presented.
基金sponsored by Key Lab.of Biomass Energy and Material,Jiangsu Province(JSBEM-S-202305)Guangdong Academy of Forestry(2022-GDFS-KJ-03).
文摘Wood,recognized as a renewable and environmentally sustainable material,plays a crucial role as an alternative energy resource within the construction industry.However,it is highly susceptible to mold and decay fungi,which can lead to surface discoloration and potentially compromise the structural integrity of wood.The advancement of nanotechnology has introduced innovative strategies for wood protection,enhancing its performance while imparting additional properties.Various approaches including nanosized metals,polymer nanocomposite and coating treatments are actively being explored in this field.Furthermore,integrating bio-based materials with nanotechnology offers a green and sustainable method for wood preservation.This paper provides an analysis,discussion,and synthesis of the applications of nanotechnology in wood protection along with its antifungal mechanisms,thereby contributing novel insights into the research landscape surrounding this topic.
基金financially supported by the National Natural Science Foundation of China(No.U2004210)Application Foundation Frontier Project of Wuhan Science and Technology Program(No.2020010601012199)City University of Hong Kong Strategic Research Grant,Hong Kong,China(No.7005505)。
文摘Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline electrolytes,the electrochemical instability and capacity degradation of VN electrode materials present significant challenges for practical applications.Herein,the capacitance decay mechanism of VN is investigated and a simple strategy to improve cycling stability of VN supercapacitor electrodes is proposed by introducing VO_(4)^(3-)anion in KOH electrolytes.Our results show that the VN electrode is electrochemical stabilization between-1.0and-0.4 V(vs.Hg/Hg O reference electrode)in 1.0 MKOH electrolyte,but demonstrates irreversible oxidation and fast capacitance decay in the potential range of-0.4 to0 V.In situ electrochemical measurements reveal that the capacitance decay of VN from-0.4 to 0 V is ascribed to the irreversible oxidation of vanadium(V)of N–V–O species by oxygen(O)of OH^(-).The as-generated oxidization species are subsequently dissolved into KOH electrolytes,thereby undermining the electrochemical stability of VN.However,this irreversible oxidation process could be hindered by introducing VO_(4)^(3-)in KOH electrolytes.A high volumetric specific capacitance of671.9 F.cm^(-3)(1 A.cm^(-3))and excellent cycling stability(120.3%over 1000 cycles)are achieved for VN nanorod electrode in KOH electrolytes containing VO_(4)^(3-).This study not only elucidates the failure mechanism of VN supercapacitor electrodes in alkaline electrolytes,but also provides new insights into enhancing pseudocapacitive energy storage of VN-based electrode materials.
基金National Natural Science Foundation of China for funding support via grant No 12175013the Interdisciplinary Research Project for Young Researchers of USTB and the Youth Teacher International Exchange&Growth Program of USTB(Fundamental Research Funds for the Central Universities,China)for funding support via grant No FRF-IDRY-21–018 and QNXM20250033,respectively.
文摘Evaluation of damage evolution effects in biodegradable pure Mg was carried out,using transmission electron microscope as surrogate irradiation for high-energy radionuclide β decay in Brachytherapy.Time-dependent quantitative defect production,evolution dynamics,and evolution statistics were revealed in-situ for two prism foils(z=[1.210],[10.10]),in as-received and heat-treated pure Mg,after 300 keV electron irradiation up to 0.468 dpa at R.T.Preferred nucleation of basal-plane interstitial-type 1/6<20.23>loops was confirmed,in addition to a small portion of prism-plane 1/3<11.20>loops.No cavities were found.A higher yield of point defect concentration and a more evident trend of defect coarsening were identified in[1.210]than in[10.10].Pre-existing dislocations(on the orders of 10^(13)−10^(14) m^(−2))in pure Mg resulted in a delay of the first occurrence of visible defects.Defect migration and elastic interactions governed the microstructural evolution of electron irradiation damage in pure Mg,giving rise to events of loop coalescence,growth,and sometimes rotation of habit plane.The influence of incident electron energy can be correlated to the rates of point defect production,and is quantifiable;however,interfered by defect cluster stability,defect mobility,and defect interactions.This forms an important theoretical basis for the application of Mg subjected to MeV-level β-decay radiation in Brachytherapy.The paper concludes with a brief comparison between Mg and conventional Ti casing,outlines the advantages and challenges,and provides reference points for the validation of Mg/Mg-alloys in Brachytherapy seed application.
基金supported by the National Natural Science Foundation of China(Grant No.11971100)the Natural Science Foundation of Shanghai(Grant No.22ZR1402300)+1 种基金supported by the National Natural Science Foundation of China(Grant No.12326430)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MA017).
文摘The present paper deals with the Cauchy problem to a two-fluid plasma model with unequal viscosities in any dimension N≥2.Employing the precise spectral analysis for the corresponding linearized system,we prove the global well-posedness provided that the initial data are close to a stable equilibrium state in critical functional framework which is not related to the energy space.Moreover,the optimal decay rates for the constructed global solution are also established.
