Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of...Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.展开更多
Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐di...Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy 展开更多
In the past decade, researchers in the fields of energy production have concentrated on the improvement of new energy storage devices. Lithium-ion batteries(LIBs) and faradaic supercapacitors(FSs) have attracted speci...In the past decade, researchers in the fields of energy production have concentrated on the improvement of new energy storage devices. Lithium-ion batteries(LIBs) and faradaic supercapacitors(FSs) have attracted special attention as a result of the rapid development of new electrode nanomaterials, especially hybrid nanomaterials, which can meet the increasingly higher requirements for future energy, such as the capability to deliver high-power performance and an extremely long life cycle. In these hybrid nanostructures, a series of synergistic effects and unique properties arising from the combination of individual components are a major factor leading to improved charge/discharge capability, energy density, and system lifetime. This paper describes the most recent progress in the growth of hybrid electrode materials for LIBs and FSs systems, focusing on the combination of zero-dimensional(0 D), one-dimensional(1 D), two-dimensional(2 D), and three-dimensional(3 D) nanomaterials, respectively.展开更多
The unique structure of zero-dimensional(0D)perovskite-analogues has attracted a great amount of research interest in recent years.To date,the current compositional library of 0D perovskites is largely limited to the ...The unique structure of zero-dimensional(0D)perovskite-analogues has attracted a great amount of research interest in recent years.To date,the current compositional library of 0D perovskites is largely limited to the lead-based Cs4PbX6(X=Cl,Br,and I)systems.In this work,we report a new synthesis of lead-free 0D Cs3BiX6(X=Cl,Br)perovskite-analogue nanocrystals(NCs)with a uniform cubic shape.We observe a broad photoluminescence peak centered at 390 nm for the 0D Cs3BiCl6 NCs at low temperatures.This feature originates from a self-trapped exciton mechanism.In situ thermal stability studies show that Cs3BiX6 NCs remain stable upon heating up to 200°C without crystal structural degradation.Moreover,we demonstrate that the Cs3BiX6 NCs can transform into other bismuth-based perovskite-analogues via facile anion exchange or metal ion insertion reactions.Our study presented here offers the opportunity for further understanding of the structure-property relationship of 0D perovskite-analogue materials,leading toward their future optoelectronic applications.展开更多
Lead halide perovskite nanocrystals(PNCs)have emerged as new-generation light-emitting materials with important potentials in optoelectronic applications.However,the toxicity of lead metal and the instabilities of PNC...Lead halide perovskite nanocrystals(PNCs)have emerged as new-generation light-emitting materials with important potentials in optoelectronic applications.However,the toxicity of lead metal and the instabilities of PNCs overwhelmingly hinder their device engineering;thus,it is still urgent to construct new single crystalline lead-free perovskites with high-performance luminescent properties.展开更多
Triangular decomposition with different properties has been used for various types of problem solving.In this paper,the concepts of pure chains and square-free pure triangular decomposition(SFPTD)of zero-dimensional p...Triangular decomposition with different properties has been used for various types of problem solving.In this paper,the concepts of pure chains and square-free pure triangular decomposition(SFPTD)of zero-dimensional polynomial systems are defined.Because of its good properties,SFPTD may be a key way to many problems related to zero-dimensional polynomial systems.Inspired by the work of Wang(2016)and of Dong and Mou(2019),the authors propose an algorithm for computing SFPTD based on Gr¨obner bases computation.The novelty of the algorithm is that the authors make use of saturated ideals and separant to ensure that the zero sets of any two pure chains are disjoint and every pure chain is square-free,respectively.On one hand,the authors prove the arithmetic complexity of the new algorithm can be single exponential in the square of the number of variables,which seems to be among the rare complexity analysis results for triangular-decomposition methods.On the other hand,the authors show experimentally that,on a large number of examples in the literature,the new algorithm is far more efficient than a popular triangular-decomposition method based on pseudodivision,and the methods based on SFPTD for real solution isolation and for computing radicals of zero-dimensional ideals are very efficient.展开更多
The origin of green emission in the zero-dimensional(0D)perovskite Cs4PbBr6 nanocrystals(NCs)remains a considerable debate.Herein,an approach involving a combination of high-pressure experiments and theoretical simula...The origin of green emission in the zero-dimensional(0D)perovskite Cs4PbBr6 nanocrystals(NCs)remains a considerable debate.Herein,an approach involving a combination of high-pressure experiments and theoretical simulation was employed to elucidate the controversial origin of photoluminescence from emissive Cs4PbBr6 NCs(E416).Results obtained from first-principles density functional theory(DFT)calculations,as implemented in the Vienna ab initio simulation package codes,implied that the photoluminescence energies from bromine vacancy decreased persistently with pressure.Experimentally,the photoluminescence energies tended to decrease in the low-pressure region,followed by an increase beyond∼1.4 GPa.While the emergent disagreement between the first-principles calculation and highpressure experiment excludes the possibility of vacancy-tuning,the consistent change observed in the pressure-dependent emission between E416 and CsPbBr_(3) NCs offered a reliable interpretation for the occurrence of green emission from a CsPbBr_(3) impurity embedded in the Cs4PbBr6 matrix.Further comprehensive analysis demonstrated that the strong green emission of E416 NCs originated from the impurity CsPbBr_(3) NCs embedded in Cs4PbBr6 matrix.Our study represents a significant step forward to a deeper understanding of the emissive origins of Cs4PbBr6 NCs and promotes the application of this novel strategy in light-emitting devices.展开更多
Rational Univariate Representation （RUR） of zero-dimensional ideals is used to describe the zeros of zero-dimensional ideals and RUR has been studied extensively. In 1999, Roullier proposed an efficient algorithm to...Rational Univariate Representation （RUR） of zero-dimensional ideals is used to describe the zeros of zero-dimensional ideals and RUR has been studied extensively. In 1999, Roullier proposed an efficient algorithm to compute RUR of zero-dimensional ideals. In this paper, we will present a new algorithm to compute Polynomial Univariate Representation （PUR） of zero-dimensional ideals. The new algorithm is based on some interesting properties of Grobner basis. The new algorithm also provides a method for testing separating elements.展开更多
New kinds of strongly zero-dimensional locales are introduced and characterized, which are different from Johnstone's, and almost all the topological properties for strongly zero-dimensional spaces have the pointl...New kinds of strongly zero-dimensional locales are introduced and characterized, which are different from Johnstone's, and almost all the topological properties for strongly zero-dimensional spaces have the pointloss localic forms. Particularly. the Stone-Cech compactification of a strongly zero-diluensional locale is stongly zero-dimensional.展开更多
In this paper,the so-called invertibility is introduced for rational univariate representations,and a characterization of the invertibility is given.It is shown that the rational univariate representations,obtained by...In this paper,the so-called invertibility is introduced for rational univariate representations,and a characterization of the invertibility is given.It is shown that the rational univariate representations,obtained by both Rouillier’s approach and Wu’s method,are invertible.Moreover,the ideal created by a given rational univariate representation is defined.Some results on invertible rational univariate representations and created ideals are established.Based on these results,a new approach is presented for decomposing the radical of a zero-dimensional polynomial ideal into an intersection of maximal ideals.展开更多
With the increasing demand for high-quality pork,more nutritional substances have been studied for the regulation of meat quality.Zero-dimensional fullerenes(C60)can modulate the biological behavior of a variety of ce...With the increasing demand for high-quality pork,more nutritional substances have been studied for the regulation of meat quality.Zero-dimensional fullerenes(C60)can modulate the biological behavior of a variety of cell lines and animals.In this study,we report the biological effects of C60 on finishing pigs at different concentrations.A total of 24 barrows(Duroc×Large White×Landrace),with an average body weight of 21.01±0.98 kg,were divided into 3 groups and each treated daily with C60(100 or 200 mg per kg feed)or a control diet until the end of the experiment.Our results showed that dietary C60 supplementation improved flesh color,marbling scores,and flavor amino acid contents of longissimus dorsi(LD)of growing-finishing pigs(P<0.05).C60 improved meat quality by regulating lipid metabolism and muscle fiber morphology by mediating the expression of genes,L-lactic dehydrogenase(LDH),myosin heavy chain(MyHC)IIa,MyHCIIb,peroxisome proliferator-activated receptor γ(PPARγ),and fatty acid transport protein 1(FATP1)(P<0.05).Moreover,C60 substantially promoted the mRNA expression of antioxidant enzyme genes(P<0.05),which also contributed to improving meat quality.These findings have important implications for the application of C60 in the livestock industry,especially for improving the meat quality of fattening pigs.展开更多
The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high...The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high-current stage does not exist.In this study,a complete prediction model for the pulse in the ion thruster is established using the zero-dimensional plasma discharge model and equivalent circuit model.The zero-dimensional plasma discharge model is used to obtain the corresponding plasma parameters by calculating the beam current,discharge current,voltage,and gas flow under actual working conditions.The input parameters of the equivalent circuit model are calculated using empirical formulae to acquire the estimated discharge waveforms.The pulse waveforms obtained using the model are found to be consistent with the experimental results.The model is used to evaluate the process of rapid changes in plasma density.Additionally,this model is employed to predict changes in the pulse waveforms when the volume of the discharge chamber and grid plate transmittance are changed.展开更多
It is well known that K<sub>0</sub>R（?）Z（?）（?）<sub>0</sub>R, where R is a commutative ring. So the Grothendieck group of R can be given by the reduced group （?）<sub>0</sub>R...It is well known that K<sub>0</sub>R（?）Z（?）（?）<sub>0</sub>R, where R is a commutative ring. So the Grothendieck group of R can be given by the reduced group （?）<sub>0</sub>R. On the other hand, linear representations of groups can be seen as the finitely generated projective modules over group rings. Thus, it is very useful to study the properties of reduced groups of group rings.展开更多
基金supported by the National Natural Science Foundation of China(Grant nos.21773218,61974063)the Sichuan Province(Grant no.2018JY0206)the China Academy of Engineering Physics(Grant no.YZJJLX2018007)。
文摘Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.
基金supported by National Natural Science Foundation of China(51672113)Six Talent Peaks Project in Jiangsu Province(2015-XCL-026)+3 种基金Natural Science Foundation of Jiangsu Province(BK20171299)State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-KF201705),Fuzhou UniversityState Key Laboratory of Advanced Technology for Materials Synthesis and Processing(2016-KF-10),Wuhan University of Technologythe Qing Lan Project Foundation of Jiangsu Province~~
文摘Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy
基金supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education(NRF-2017R1D1A1A09000642)by a grant from the R&D Program of the Korea Railroad Research Institute (KRRI), Republic of Korea
文摘In the past decade, researchers in the fields of energy production have concentrated on the improvement of new energy storage devices. Lithium-ion batteries(LIBs) and faradaic supercapacitors(FSs) have attracted special attention as a result of the rapid development of new electrode nanomaterials, especially hybrid nanomaterials, which can meet the increasingly higher requirements for future energy, such as the capability to deliver high-power performance and an extremely long life cycle. In these hybrid nanostructures, a series of synergistic effects and unique properties arising from the combination of individual components are a major factor leading to improved charge/discharge capability, energy density, and system lifetime. This paper describes the most recent progress in the growth of hybrid electrode materials for LIBs and FSs systems, focusing on the combination of zero-dimensional(0 D), one-dimensional(1 D), two-dimensional(2 D), and three-dimensional(3 D) nanomaterials, respectively.
基金support from Brown University startup funds and the National Science Foundation(OIA-1538893)K.H.-K.is supported by the U.S.Department of Education GAANN research fellowship(P200A150037)。
文摘The unique structure of zero-dimensional(0D)perovskite-analogues has attracted a great amount of research interest in recent years.To date,the current compositional library of 0D perovskites is largely limited to the lead-based Cs4PbX6(X=Cl,Br,and I)systems.In this work,we report a new synthesis of lead-free 0D Cs3BiX6(X=Cl,Br)perovskite-analogue nanocrystals(NCs)with a uniform cubic shape.We observe a broad photoluminescence peak centered at 390 nm for the 0D Cs3BiCl6 NCs at low temperatures.This feature originates from a self-trapped exciton mechanism.In situ thermal stability studies show that Cs3BiX6 NCs remain stable upon heating up to 200°C without crystal structural degradation.Moreover,we demonstrate that the Cs3BiX6 NCs can transform into other bismuth-based perovskite-analogues via facile anion exchange or metal ion insertion reactions.Our study presented here offers the opportunity for further understanding of the structure-property relationship of 0D perovskite-analogue materials,leading toward their future optoelectronic applications.
基金supports from the National Nature Science Foundation of China(no.2217011475)Shandong Provincial Natural Science Foundation(no.ZR2020KB012)+1 种基金Fund of state key laboratory of structural chemistry(no.20210015)and Young Innovative Talents Introduction&Cultivation Program for Colleges and Universities of Shandong Province:Innovative Research Team on Optoelectronic Functional Materials.
文摘Lead halide perovskite nanocrystals(PNCs)have emerged as new-generation light-emitting materials with important potentials in optoelectronic applications.However,the toxicity of lead metal and the instabilities of PNCs overwhelmingly hinder their device engineering;thus,it is still urgent to construct new single crystalline lead-free perovskites with high-performance luminescent properties.
基金supported by National Key R&D Program of China under Grant No.2022YFA1005102the National Natural Science Foundation of China under Grant No.61732001。
文摘Triangular decomposition with different properties has been used for various types of problem solving.In this paper,the concepts of pure chains and square-free pure triangular decomposition(SFPTD)of zero-dimensional polynomial systems are defined.Because of its good properties,SFPTD may be a key way to many problems related to zero-dimensional polynomial systems.Inspired by the work of Wang(2016)and of Dong and Mou(2019),the authors propose an algorithm for computing SFPTD based on Gr¨obner bases computation.The novelty of the algorithm is that the authors make use of saturated ideals and separant to ensure that the zero sets of any two pure chains are disjoint and every pure chain is square-free,respectively.On one hand,the authors prove the arithmetic complexity of the new algorithm can be single exponential in the square of the number of variables,which seems to be among the rare complexity analysis results for triangular-decomposition methods.On the other hand,the authors show experimentally that,on a large number of examples in the literature,the new algorithm is far more efficient than a popular triangular-decomposition method based on pseudodivision,and the methods based on SFPTD for real solution isolation and for computing radicals of zero-dimensional ideals are very efficient.
基金the National Science Foundation of China(nos.21725304,11774125,and 21673100)the Chang Jiang Scholars Program of China(no.T2016051)+1 种基金Changbai Mountain Scholars Program(no.2013007)Jilin Provincial Science&Technology Development Program(no.20190103044JH).
文摘The origin of green emission in the zero-dimensional(0D)perovskite Cs4PbBr6 nanocrystals(NCs)remains a considerable debate.Herein,an approach involving a combination of high-pressure experiments and theoretical simulation was employed to elucidate the controversial origin of photoluminescence from emissive Cs4PbBr6 NCs(E416).Results obtained from first-principles density functional theory(DFT)calculations,as implemented in the Vienna ab initio simulation package codes,implied that the photoluminescence energies from bromine vacancy decreased persistently with pressure.Experimentally,the photoluminescence energies tended to decrease in the low-pressure region,followed by an increase beyond∼1.4 GPa.While the emergent disagreement between the first-principles calculation and highpressure experiment excludes the possibility of vacancy-tuning,the consistent change observed in the pressure-dependent emission between E416 and CsPbBr_(3) NCs offered a reliable interpretation for the occurrence of green emission from a CsPbBr_(3) impurity embedded in the Cs4PbBr6 matrix.Further comprehensive analysis demonstrated that the strong green emission of E416 NCs originated from the impurity CsPbBr_(3) NCs embedded in Cs4PbBr6 matrix.Our study represents a significant step forward to a deeper understanding of the emissive origins of Cs4PbBr6 NCs and promotes the application of this novel strategy in light-emitting devices.
基金supported by National Key Basic Research Project of China(Grant No. 2011CB302400)National Natural Science Foundation of China (Grant Nos. 10971217,60821002/F02)
文摘Rational Univariate Representation （RUR） of zero-dimensional ideals is used to describe the zeros of zero-dimensional ideals and RUR has been studied extensively. In 1999, Roullier proposed an efficient algorithm to compute RUR of zero-dimensional ideals. In this paper, we will present a new algorithm to compute Polynomial Univariate Representation （PUR） of zero-dimensional ideals. The new algorithm is based on some interesting properties of Grobner basis. The new algorithm also provides a method for testing separating elements.
基金Supported by the NSF of Chinathe SFEM of China the Project of "Excellent Scholars Crossing the Centuries" of the Ministry of Education of China
文摘New kinds of strongly zero-dimensional locales are introduced and characterized, which are different from Johnstone's, and almost all the topological properties for strongly zero-dimensional spaces have the pointloss localic forms. Particularly. the Stone-Cech compactification of a strongly zero-diluensional locale is stongly zero-dimensional.
基金the National Natural Science Foundation of China under Grant No.12161057。
文摘In this paper,the so-called invertibility is introduced for rational univariate representations,and a characterization of the invertibility is given.It is shown that the rational univariate representations,obtained by both Rouillier’s approach and Wu’s method,are invertible.Moreover,the ideal created by a given rational univariate representation is defined.Some results on invertible rational univariate representations and created ideals are established.Based on these results,a new approach is presented for decomposing the radical of a zero-dimensional polynomial ideal into an intersection of maximal ideals.
基金the Innovation Team of Key areas of the Ministry of Science and Technology,Science and Technology Leadership Program of Hunan Province(2019RS3020)Special Fund for Key Program of Science and Technology of Yunnan Province(202102AE090046)。
文摘With the increasing demand for high-quality pork,more nutritional substances have been studied for the regulation of meat quality.Zero-dimensional fullerenes(C60)can modulate the biological behavior of a variety of cell lines and animals.In this study,we report the biological effects of C60 on finishing pigs at different concentrations.A total of 24 barrows(Duroc×Large White×Landrace),with an average body weight of 21.01±0.98 kg,were divided into 3 groups and each treated daily with C60(100 or 200 mg per kg feed)or a control diet until the end of the experiment.Our results showed that dietary C60 supplementation improved flesh color,marbling scores,and flavor amino acid contents of longissimus dorsi(LD)of growing-finishing pigs(P<0.05).C60 improved meat quality by regulating lipid metabolism and muscle fiber morphology by mediating the expression of genes,L-lactic dehydrogenase(LDH),myosin heavy chain(MyHC)IIa,MyHCIIb,peroxisome proliferator-activated receptor γ(PPARγ),and fatty acid transport protein 1(FATP1)(P<0.05).Moreover,C60 substantially promoted the mRNA expression of antioxidant enzyme genes(P<0.05),which also contributed to improving meat quality.These findings have important implications for the application of C60 in the livestock industry,especially for improving the meat quality of fattening pigs.
基金the financial support from National Natural Science Foundation of China(Nos.11402025,11475019,and 11702123)the National Key Laboratory of Science and Technology on Vacuum Technology&Physics(No.ZWK1608)+1 种基金the Advanced Space Propulsion Laboratory of BICEBeijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology(No.Lab ASP-2018-03)。
文摘The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high-current stage does not exist.In this study,a complete prediction model for the pulse in the ion thruster is established using the zero-dimensional plasma discharge model and equivalent circuit model.The zero-dimensional plasma discharge model is used to obtain the corresponding plasma parameters by calculating the beam current,discharge current,voltage,and gas flow under actual working conditions.The input parameters of the equivalent circuit model are calculated using empirical formulae to acquire the estimated discharge waveforms.The pulse waveforms obtained using the model are found to be consistent with the experimental results.The model is used to evaluate the process of rapid changes in plasma density.Additionally,this model is employed to predict changes in the pulse waveforms when the volume of the discharge chamber and grid plate transmittance are changed.
文摘It is well known that K<sub>0</sub>R（?）Z（?）（?）<sub>0</sub>R, where R is a commutative ring. So the Grothendieck group of R can be given by the reduced group （?）<sub>0</sub>R. On the other hand, linear representations of groups can be seen as the finitely generated projective modules over group rings. Thus, it is very useful to study the properties of reduced groups of group rings.
