This article is concerned with blow-up solutions of the Cauchy problem of critical nonlinear SchrSdinger equation with a Stark potential. By using the variational characterization of corresponding ground state, the li...This article is concerned with blow-up solutions of the Cauchy problem of critical nonlinear SchrSdinger equation with a Stark potential. By using the variational characterization of corresponding ground state, the limiting behavior of blow-up solutions with critical and small super-critical mass are obtained in the natural energy space ∑ = {u ∈ H^1; fRN ｜x｜^2｜u｜^2dx 〈 ＋∞）}. Moreover, an interesting concentration property of the blow-up solutions with critical mass is gotten, which reads that ｜u（t, x）｜^2→ ｜｜Q｜｜L^2 2 δx=x1 as t → T.展开更多
There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial gro...There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.展开更多
This paper is concerned with the blow-up solutions of the Cauchy problem for Gross-Pitaevskii equation.In terms of Merle and Raphёel＇s arguments as well as Carles＇ transformation,the limiting profiles of blow-up so...This paper is concerned with the blow-up solutions of the Cauchy problem for Gross-Pitaevskii equation.In terms of Merle and Raphёel＇s arguments as well as Carles＇ transformation,the limiting profiles of blow-up solutions are obtained.In addition,the nonexistence of a strong limit at the blow-up time and the existence of L2 profile outside the blow-up point for the blow-up solutions are obtained.展开更多
The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biod...The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past(1950-1980) distribution areas were extracted from the Vegetation Map of China(1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future(under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm(MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area(4.9×10~4 km^2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×10~4 km^2. But only 15.7% of its present potential distribution area(14.0×10~4 km^2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total ar展开更多
Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and sel...Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and selectivity is currently urgent but remains great challenge.Herein,we systematically investigate the NRR catalytic activities of single and double transition metal atoms(TM=Fe,Co,Ni and Mo)anchored on g-C_(6)N_(6) monolayers by performing first-principles calculation.Based on the stability,activity,and selectivity analysis,Mo_(2)@g-C_(6)N_(6) monolayer is screened out as the most promising candidate for NRR.Further exploration of the reaction mechanism demonstrates that the Mo dimer anchored on g-C_(6)N_(6) can sufficiently activate and efficiently reduce the inert nitrogen molecule to ammonia through a preferred distal pathway with a particularly low limiting potential of -0.06 V.In addition,we find that Mo_(2)@g-C_(6)N_(6) has excellent NRR selectivity over the competing hydrogen evolution reaction,with the Faradaic efficiency being 100%.Our work not only predicts a kind of ideal NRR electrocatalyst but also encouraging more experimental and theoretical efforts to develop novel double-atom catalysts(DACs)for NRR.展开更多
We study spectral properties of a quantum Hamiltonian with a complex-valued energy-dependent potential related to a model introduced in physics of nuclear reactions[30]and we prove that the principle of limiting absor...We study spectral properties of a quantum Hamiltonian with a complex-valued energy-dependent potential related to a model introduced in physics of nuclear reactions[30]and we prove that the principle of limiting absorption holds at any point of a large subset of the essential spectrum.When an additional dissipative or smallness hypothesis is assumed on the potential,we show that the principle of limiting absorption holds at any point of the essential spectrum.展开更多
The term neurodegeneration emphasizes the destruction of neuronal cells as the primary explanation of many major neurological illnesses, including Alzheimer’s disease. Specialized functioning of cells requires more c...The term neurodegeneration emphasizes the destruction of neuronal cells as the primary explanation of many major neurological illnesses, including Alzheimer’s disease. Specialized functioning of cells requires more cellular energy than is needed for basic cell survival. Cells can acquire energy both from the metabolism of food and from the alternative cellular energy (ACE) pathway. The ACE pathway is an added dynamic (kinetic) quality of the body’s fluids occurring from the absorption of an external force termed KELEA (Kinetic Energy Limiting Electrostatic Attraction). KELEA is attracted to separated electrical charges and is seemingly partially released as the charges become more closely linked. As suggested elsewhere, the fluctuating electrical activity in the brain may attract KELEA from the environment and, thereby, contribute to the body’s ACE pathway. Certain illnesses affecting the brain may impede this proposed antenna function of the brain, leading to a systemic insufficiency of cellular energy (ICE). Furthermore, individual neurons may derive some of the energy for their own activities from the repetitive depolarization of the cell. This may explain why hyper-excitability of neurons can occur in response to cell damage. This adaptive mechanism is unlikely to be sustainable, however, especially if there is a continuing need to synthesize neurotransmitters and membrane ion channels. The energy deficient neurons would then become quiescent and, although remaining viable, would not perform their intended specialized functions. Actual cell death would not necessarily occur till much later in the disease process. The distinction between quiescent and degenerated cells is important since the ACE pathway can be enhanced by several means, including the regular consumption of KELEA activated water. This, in turn, may improve the proposed antenna function of individual neurons, leading to a sustained restoration of specialized function via the ACE pathway. This paper explores this novel concept and provides 展开更多
Living organisms derive energy for cellular activities through three primary mechanisms. The first is photosynthesis, which is restricted to plants and certain bacteria. It uses energy in sunlight to combine carbon di...Living organisms derive energy for cellular activities through three primary mechanisms. The first is photosynthesis, which is restricted to plants and certain bacteria. It uses energy in sunlight to combine carbon dioxide with water to form carbohydrates plus oxygen. The second is chemical energy, which is ob-tainable by all organisms from the cellular metabolism of carbohydrates and other organic molecules. The third mechanism of obtaining cellular energy is the alternative cellular energy (ACE) pathway. The ACE pathway is expressed as an added dynamic (kinetic) quality of the body’s fluids. It results from the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). The fundamental role of KELEA is presumably to pre-vent the fusion and annihilation of electrostatically attracted opposing electrical charges. KELEA can loosen the hydrogen bonding between fluid molecules. KELEA benefits living organisms in part by enabling more efficient biochemical reactions. Cells require a minimal amount of energy to remain viable. Additional energy is required to undertake specialized cellular functions. Illnesses result if cells have insufficient cellular energy (ICE) for their specialized functions. Since KELEA is attracted to separated electrical charges, it is presumably attracted to the electrical charges comprising the membrane potential of cells. It is proposed that the depolarization of neuronal cells leads to the partial release of KELEA for use by the depolarized cell and as a contribution to the overall activation of the body’s fluids. Many brain illnesses currently attributed to cellular neurodegeneration are explainable as neuronal cells’ adaptations to ICE. The adaptations likely comprise initial hyper-excitability to obtain additional KELEA, followed by functional quiescence prior to actual neuronal cell death. Clinical recovery during both the hyper-excitable and hypoactive phases is potentially achievable by enhancing the ACE pathway. Furthermore, among the r展开更多
Kerov[16,17] proved that Wigner＇s semi-circular law in Gauss[an unitary ensembles is the transition distribution of the omega curve discovered by Vershik and Kerov[34] for the limit shape of random partitions under t...Kerov[16,17] proved that Wigner＇s semi-circular law in Gauss[an unitary ensembles is the transition distribution of the omega curve discovered by Vershik and Kerov[34] for the limit shape of random partitions under the Plancherel measure. This establishes a close link between random Plancherel partitions and Gauss[an unitary ensembles, In this paper we aim to consider a general problem, namely, to characterize the transition distribution of the limit shape of random Young diagrams under Poissonized Plancherel measures in a periodic potential, which naturally arises in Nekrasov＇s partition functions and is further studied by Nekrasov and Okounkov[25] and Okounkov[28,29]. We also find an associated matrix mode[ for this transition distribution. Our argument is based on a purely geometric analysis on the relation between matrix models and SeibergWitten differentials.展开更多
基金Supported by National Science Foundation of China (11071177)Excellent Youth Foundation of Sichuan Province (2012JQ0011)
文摘This article is concerned with blow-up solutions of the Cauchy problem of critical nonlinear SchrSdinger equation with a Stark potential. By using the variational characterization of corresponding ground state, the limiting behavior of blow-up solutions with critical and small super-critical mass are obtained in the natural energy space ∑ = {u ∈ H^1; fRN ｜x｜^2｜u｜^2dx 〈 ＋∞）}. Moreover, an interesting concentration property of the blow-up solutions with critical mass is gotten, which reads that ｜u（t, x）｜^2→ ｜｜Q｜｜L^2 2 δx=x1 as t → T.
基金The Natural Science Foundation of Zhejiang Province, China(No. M303106)
文摘There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.
基金Supported by the National Natural Science Foundation of China (No.10771151,No.10747148)
文摘This paper is concerned with the blow-up solutions of the Cauchy problem for Gross-Pitaevskii equation.In terms of Merle and Raphёel＇s arguments as well as Carles＇ transformation,the limiting profiles of blow-up solutions are obtained.In addition,the nonexistence of a strong limit at the blow-up time and the existence of L2 profile outside the blow-up point for the blow-up solutions are obtained.
基金This research was supported by the National Key Basic Research Program of China(2015FY210200)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19050402)+1 种基金the Assessment Methods for Red List of Ecosystems in China Program of the Ministry of Ecology and Environment of Chinathe Characteristic Analysis of Important Ecosystems in China Program of the Chinese Research Academy of Environmental Sciences.Assistance from many colleagues enabled this study.We thank Dr.WANG Zi,Dr.WU Popo,Ms.ZHU Hong,and Dr.PANG Zhe for their great help during the field survey work.
文摘The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past(1950-1980) distribution areas were extracted from the Vegetation Map of China(1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future(under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm(MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area(4.9×10~4 km^2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×10~4 km^2. But only 15.7% of its present potential distribution area(14.0×10~4 km^2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total ar
基金supported by the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2020KJ008)the Natural Science Foundation of Tianjin(No.18JCQNJC76000)+3 种基金the College Students'Innovation and Entrepreneurship Training Program of Tianjin(No.202110065112)Science and Technology Research Project of Hubei Provincial De-partment of Education(No.D20212603)Hubei University of Arts and Science(Nos.2020kypytd002,XK2021024)China Scholarship Council.
文摘Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and selectivity is currently urgent but remains great challenge.Herein,we systematically investigate the NRR catalytic activities of single and double transition metal atoms(TM=Fe,Co,Ni and Mo)anchored on g-C_(6)N_(6) monolayers by performing first-principles calculation.Based on the stability,activity,and selectivity analysis,Mo_(2)@g-C_(6)N_(6) monolayer is screened out as the most promising candidate for NRR.Further exploration of the reaction mechanism demonstrates that the Mo dimer anchored on g-C_(6)N_(6) can sufficiently activate and efficiently reduce the inert nitrogen molecule to ammonia through a preferred distal pathway with a particularly low limiting potential of -0.06 V.In addition,we find that Mo_(2)@g-C_(6)N_(6) has excellent NRR selectivity over the competing hydrogen evolution reaction,with the Faradaic efficiency being 100%.Our work not only predicts a kind of ideal NRR electrocatalyst but also encouraging more experimental and theoretical efforts to develop novel double-atom catalysts(DACs)for NRR.
文摘We study spectral properties of a quantum Hamiltonian with a complex-valued energy-dependent potential related to a model introduced in physics of nuclear reactions[30]and we prove that the principle of limiting absorption holds at any point of a large subset of the essential spectrum.When an additional dissipative or smallness hypothesis is assumed on the potential,we show that the principle of limiting absorption holds at any point of the essential spectrum.
文摘The term neurodegeneration emphasizes the destruction of neuronal cells as the primary explanation of many major neurological illnesses, including Alzheimer’s disease. Specialized functioning of cells requires more cellular energy than is needed for basic cell survival. Cells can acquire energy both from the metabolism of food and from the alternative cellular energy (ACE) pathway. The ACE pathway is an added dynamic (kinetic) quality of the body’s fluids occurring from the absorption of an external force termed KELEA (Kinetic Energy Limiting Electrostatic Attraction). KELEA is attracted to separated electrical charges and is seemingly partially released as the charges become more closely linked. As suggested elsewhere, the fluctuating electrical activity in the brain may attract KELEA from the environment and, thereby, contribute to the body’s ACE pathway. Certain illnesses affecting the brain may impede this proposed antenna function of the brain, leading to a systemic insufficiency of cellular energy (ICE). Furthermore, individual neurons may derive some of the energy for their own activities from the repetitive depolarization of the cell. This may explain why hyper-excitability of neurons can occur in response to cell damage. This adaptive mechanism is unlikely to be sustainable, however, especially if there is a continuing need to synthesize neurotransmitters and membrane ion channels. The energy deficient neurons would then become quiescent and, although remaining viable, would not perform their intended specialized functions. Actual cell death would not necessarily occur till much later in the disease process. The distinction between quiescent and degenerated cells is important since the ACE pathway can be enhanced by several means, including the regular consumption of KELEA activated water. This, in turn, may improve the proposed antenna function of individual neurons, leading to a sustained restoration of specialized function via the ACE pathway. This paper explores this novel concept and provides
文摘Living organisms derive energy for cellular activities through three primary mechanisms. The first is photosynthesis, which is restricted to plants and certain bacteria. It uses energy in sunlight to combine carbon dioxide with water to form carbohydrates plus oxygen. The second is chemical energy, which is ob-tainable by all organisms from the cellular metabolism of carbohydrates and other organic molecules. The third mechanism of obtaining cellular energy is the alternative cellular energy (ACE) pathway. The ACE pathway is expressed as an added dynamic (kinetic) quality of the body’s fluids. It results from the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). The fundamental role of KELEA is presumably to pre-vent the fusion and annihilation of electrostatically attracted opposing electrical charges. KELEA can loosen the hydrogen bonding between fluid molecules. KELEA benefits living organisms in part by enabling more efficient biochemical reactions. Cells require a minimal amount of energy to remain viable. Additional energy is required to undertake specialized cellular functions. Illnesses result if cells have insufficient cellular energy (ICE) for their specialized functions. Since KELEA is attracted to separated electrical charges, it is presumably attracted to the electrical charges comprising the membrane potential of cells. It is proposed that the depolarization of neuronal cells leads to the partial release of KELEA for use by the depolarized cell and as a contribution to the overall activation of the body’s fluids. Many brain illnesses currently attributed to cellular neurodegeneration are explainable as neuronal cells’ adaptations to ICE. The adaptations likely comprise initial hyper-excitability to obtain additional KELEA, followed by functional quiescence prior to actual neuronal cell death. Clinical recovery during both the hyper-excitable and hypoactive phases is potentially achievable by enhancing the ACE pathway. Furthermore, among the r
基金Supported by the National Natural Science Foundation of China(No.10671176)
文摘Kerov[16,17] proved that Wigner＇s semi-circular law in Gauss[an unitary ensembles is the transition distribution of the omega curve discovered by Vershik and Kerov[34] for the limit shape of random partitions under the Plancherel measure. This establishes a close link between random Plancherel partitions and Gauss[an unitary ensembles, In this paper we aim to consider a general problem, namely, to characterize the transition distribution of the limit shape of random Young diagrams under Poissonized Plancherel measures in a periodic potential, which naturally arises in Nekrasov＇s partition functions and is further studied by Nekrasov and Okounkov[25] and Okounkov[28,29]. We also find an associated matrix mode[ for this transition distribution. Our argument is based on a purely geometric analysis on the relation between matrix models and SeibergWitten differentials.
