The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the d...The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.展开更多
Based on the Eigen and Crow-Kimura models with a single-peak fitness landscape, we propose the fitness values of all sequence types to be Gausslan distributed random variables to incorporate the effects of the fluctua...Based on the Eigen and Crow-Kimura models with a single-peak fitness landscape, we propose the fitness values of all sequence types to be Gausslan distributed random variables to incorporate the effects of the fluctuations of the fitness landscapes (noise of environments) and investigate the concentration distribution and error threshold of quasispecies by performing an ensemble average within this theoretical framework. We find that a small fluctuation of the fitness landscape causes only a slight change in the concentration distribution and error threshold, which implies that the error threshold is stable against small perturbations. However, for a sizable fluctuation, quite different from the previous deterministic models, our statistical results show that the transition from quasi-species to error catastrophe is not so sharp, indicating that the error threshold is located within a certain range and has a shift toward a larger value. Our results are qualitatively in agreement with the experimental data and provide a new implication for antiviral strategies.展开更多
In the early morning hours of May 23, 2004, passengers in Terminal 2E at the Charles de Gaulle Airport in Paris partially collapsed resulting in several fatalities. Structural failure was caused by multiple reasons, a...In the early morning hours of May 23, 2004, passengers in Terminal 2E at the Charles de Gaulle Airport in Paris partially collapsed resulting in several fatalities. Structural failure was caused by multiple reasons, all contributing to failure. Similar structures have been successfully erected and built around the world. One famous and comparable structure is the Berlin Main Railway Station. After investigations, it becomes clear that Charles de Gaulle Airport lacks suitable and effective geometry, which is present in Berlin Railway Station.展开更多
There are several important generalizations of martingales such as games fairer with time, quasi-mils and sequential martingales in the limit. In the note, we shall consider all possible structures of a probability sp...There are several important generalizations of martingales such as games fairer with time, quasi-mils and sequential martingales in the limit. In the note, we shall consider all possible structures of a probability space (Ω,A, (An), P) associated with a stochastic basis(An) of sub a-fields of A with An ↑ A. Then, we shall apply them to establish some comparison results for the aforementioned generalizations of martingales.展开更多
This paper proposes a new type of pulse launcher that applies the principle of linear motors. The stator, viz. gun barrel, of the launcher has a new structure of one segment of iron core consisting of 3 staggered lami...This paper proposes a new type of pulse launcher that applies the principle of linear motors. The stator, viz. gun barrel, of the launcher has a new structure of one segment of iron core consisting of 3 staggered laminations. This structure is helpful in advancing the thrust force per volume. Based on introducing the structure and the working principles, this paper resolves the electromagnetic thrusting force and performs mechanical analysis and experiments on the sample launcher. The research shows that this launcher is simple and brushless structure with brief controlling.展开更多
The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and...The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and Bangladesh. These viruses enter host cells via a class I viral fusion mechanism mediated by their attachment and fusion envelope glycoproteins;efficient membrane fusion requires both these glycoproteins in conjunction with specific virus receptors present on susceptible host cells. The henipavirus attachment glycoprotein interacts with a cellular B class ephrin protein receptor triggering conformational alterations leading to the activation of the viral fusion(F) glycoprotein. The analysis of monoclonal antibody(mAb) reactivity with G has revealed measurable alterations in the antigenic structure of the glycoprotein following its binding interaction with receptor. These observations only appear to occur with full-length native G glycoprotein,which is a tetrameric oligomer,and not with soluble forms of G(sG) ,which are disulfide-linked dimers. Single amino acid mutations in a heptad repeat-like structure within the stalk domain of G can disrupt its association with F and subsequent membrane fusion promotion activity. Notably,these mutants of G also appear to confer a post-receptor bound conformation implicating the stalk domain as an important element in the G glycoprotein's structure and functional relationship with F. Together,these observations suggest fusion is dependent on a specific interaction between the F and G glycoproteins of the henipaviruses. Further,receptor binding induces measurable changes in the G glycoprotein that appear to be greatest in respect to the interactions between the pairs of dimers comprising its native tetrameric structure. These receptor-induced conformational changes may be associated with the G glycoprotein's promotion of the fusion activity of F.展开更多
The radiological characterization is to determine the type, the distribution and the radioactivity of the radionuclide in the reactor by investigation of the information, instrumentation detection, sampling analyses a...The radiological characterization is to determine the type, the distribution and the radioactivity of the radionuclide in the reactor by investigation of the information, instrumentation detection, sampling analyses and theoretical calculation. It is used for determination of the decommissioning implementation option and radiological protection measure of the workers. After completion of the decommissioning it is used for determination of the site release. The radiological characterization should go through whole decommissioning process, which includes: the collection and review of historical file, the performing calculation of radionuclide inventory in the reactor, in situ measurement, sampling analyses, the review and evaluation of the data obtained and the comparison of calculated result with measured date etc.. The special attention should be paid to the radiological characterization information from the key part of reactor in decommissioning end state. The sampling from the "hot spot" should not be lost; the number of the sampling should be reasonable based on reliable statistics. The radioactivity density for site release should comply with the guide, standard and regulation of International Atomic Energy Agency and China.展开更多
In this paper,the possibility of the monatomic chain (MC) formation for ZnO material was studied by molecular dynamics (MD) simulation.The process of MC formation and the effects of temperature,strain rate and size we...In this paper,the possibility of the monatomic chain (MC) formation for ZnO material was studied by molecular dynamics (MD) simulation.The process of MC formation and the effects of temperature,strain rate and size were studied extensively.The tensile process can be divided to be five stages and the ZnO diatomic chain (DC) can be found.The MD results show that most atoms in MC came from the original surface of ZnO nanowires (NWs).Temperature and strain rate are two important factors affecting the process,and both high temperature and low strain rate in a certain range would be beneficial to the formation of DC.Moreover,the effects of strain rate and temperature could attribute to the Arrhenius model and the energy release mechanism.Furthermore,multi-shell structure was found for the samples under tensile strain and the layer-layer distance was about 3.Our studies based on density functional theory showed that the most stable structure of ZnO DC was confirmed to be linear,and the I-V curve was also got using ATK.展开更多
The rational design and synthesis of hierarchically hollow nanostructures with controlled spatial architecture and composition are significant in electrocatalysis owing to their abundant active sites and the expedited...The rational design and synthesis of hierarchically hollow nanostructures with controlled spatial architecture and composition are significant in electrocatalysis owing to their abundant active sites and the expedited electron/mass transfer.Electrocatalytic nitrate reduction to ammonia is of great interest from the points of environmental protection and energy saving.However,the development of this technology is hindered by the lack of efficient nitrate-toammonia electrocatalysts and the kinetically sluggish oxygen evolution reaction at the anode.Herein,a novel self-template conversion method was developed for the synthesis of Co3O4@Ni O hierarchical nanotubes(Co3O4@Ni O HNTs)with Ni O porous nanosheets assembled on Co3O4nanotubes.The as-obtained Co3O4@Ni O HNTs exhibited an outstanding performance for both the cathodic nitrate electroreduction to ammonia reaction and the anodic tetrahydroisoquinolines(THIQs)semi-dehydrogenation to dihydroisoquinolines(DHIQs).Importantly,a two-electrode system of Co3O4@Ni O HNTs||Co3O4@Ni O HNTs was constructed for the simultaneous synthesis of ammonia and DHIQs with high selectivity and robust stability.展开更多
A general method is developed to prepare durable hybrid nanocatalysts by nanostructuring the surface of gold wires via simple alloying and dealloying. The resulting nanoporous gold/Au (NPG/Au) wire catalysts possess...A general method is developed to prepare durable hybrid nanocatalysts by nanostructuring the surface of gold wires via simple alloying and dealloying. The resulting nanoporous gold/Au (NPG/Au) wire catalysts possess nanoporous skins with their thicknesses on robust metal wires specified in a highly controllable manner. As a demonstration, the as-obtained NPG/Au was shown to be a highly active, chemo-selective, and recyclable catalyst for the reduction of nitro com- pounds and azides using organosilanes as reducing agents.展开更多
A highly sensitive in-situ turbidity sensor with the low power consumption was proposed and evaluated in this study. To meet the practical requirements of the in-situ detection, we have designed the light scattering p...A highly sensitive in-situ turbidity sensor with the low power consumption was proposed and evaluated in this study. To meet the practical requirements of the in-situ detection, we have designed the light scattering path, watertight mechanical structure, and ultra-weak scattering light detecting method. Experiments showed that the sensor had a sensitivity of 0.0076 FTU with the concentration range of 0 - 25 FTU and the R-square of 0.9999. The sensor could withstand the water pressure in depth of 1000m and had the low power consumption in the active mode 10.4mA, sleep mode 65 pA with a supply voltage of 8.4V. Southern China Sea buoy experiments indicated that the sensor could work well in the actual in-situ environment. In comparison with sensors of other companies, our sensor had relatively more comprehensive performance.展开更多
Using the first-principles band-structure method and a special quasirandom structure(SQS) approach,we have systematically calculated the alloy bowing coefficients and the nature band offsets of SnxZn1-x Te alloys.We s...Using the first-principles band-structure method and a special quasirandom structure(SQS) approach,we have systematically calculated the alloy bowing coefficients and the nature band offsets of SnxZn1-x Te alloys.We show that the bowing coefficients and band gaps of these alloys are sensitively composition dependent.Due to wave functions full overlapping and delocalization of the Sn outermost p orbits and Zn s orbits,the coupling between these states is very strong,resulting in a significant downshift of conduction band edge with the increase of the Sn concentration x,While the valence band edge keeps almost unchanged compared with that of the binary ZnTe,thus improving the possibility for ambipolar-doping.展开更多
Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and...Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and opening from the perspective of state transformation, and explores the deep-level causes of the difficulties contemporary China is facing in its economic and social development. It argues that the Chinese state has gradually become a developmental state with a new form, which has played an important role in promoting the development of China's economy and society but meanwhile has brought some negative impacts. China has made many efforts to go beyond the developmental state, and achieved notable success in various aspects since 2002, but there are still many problems, especially when struck by the 2008 world financial crisis; the negative impacts of the developmental state are gradually emerging. Moreover, the Chinese government still tends to sidestep some systemic and structural problems, and some policies are in fact consolidating the dominance of the old system, which will inevitably increase the difficulties for the Chinese state to go beyond the developmental state.展开更多
基金Supported by the National Natural Science Foundation of China(70503025)the Knowledge Innovation Project of Chinese Academy of Sci-ences(KZCX2-YW-305-2+3 种基金KSCX2-YW-N-039)the National Project of Scientific and Technical Supporting Programs(2006BAC08B032006BAC08B06)international cooperation program of science and technolo-gy ministry(2006DFB919201).~~
文摘The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10475008, 10675170, and 10435020, and the Department of Nuclear Physics of China Institute of Atomic Energy under Grant Nos. 11SZZ-200501 and 11SZZ-200601
文摘Based on the Eigen and Crow-Kimura models with a single-peak fitness landscape, we propose the fitness values of all sequence types to be Gausslan distributed random variables to incorporate the effects of the fluctuations of the fitness landscapes (noise of environments) and investigate the concentration distribution and error threshold of quasispecies by performing an ensemble average within this theoretical framework. We find that a small fluctuation of the fitness landscape causes only a slight change in the concentration distribution and error threshold, which implies that the error threshold is stable against small perturbations. However, for a sizable fluctuation, quite different from the previous deterministic models, our statistical results show that the transition from quasi-species to error catastrophe is not so sharp, indicating that the error threshold is located within a certain range and has a shift toward a larger value. Our results are qualitatively in agreement with the experimental data and provide a new implication for antiviral strategies.
文摘In the early morning hours of May 23, 2004, passengers in Terminal 2E at the Charles de Gaulle Airport in Paris partially collapsed resulting in several fatalities. Structural failure was caused by multiple reasons, all contributing to failure. Similar structures have been successfully erected and built around the world. One famous and comparable structure is the Berlin Main Railway Station. After investigations, it becomes clear that Charles de Gaulle Airport lacks suitable and effective geometry, which is present in Berlin Railway Station.
基金Supported by the Natural Science Foundation of the Education Department of Henan province(200510483002)
文摘There are several important generalizations of martingales such as games fairer with time, quasi-mils and sequential martingales in the limit. In the note, we shall consider all possible structures of a probability space (Ω,A, (An), P) associated with a stochastic basis(An) of sub a-fields of A with An ↑ A. Then, we shall apply them to establish some comparison results for the aforementioned generalizations of martingales.
文摘This paper proposes a new type of pulse launcher that applies the principle of linear motors. The stator, viz. gun barrel, of the launcher has a new structure of one segment of iron core consisting of 3 staggered laminations. This structure is helpful in advancing the thrust force per volume. Based on introducing the structure and the working principles, this paper resolves the electromagnetic thrusting force and performs mechanical analysis and experiments on the sample launcher. The research shows that this launcher is simple and brushless structure with brief controlling.
基金supported in part by NIH grant AI054715 to C.C.B.
文摘The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and Bangladesh. These viruses enter host cells via a class I viral fusion mechanism mediated by their attachment and fusion envelope glycoproteins;efficient membrane fusion requires both these glycoproteins in conjunction with specific virus receptors present on susceptible host cells. The henipavirus attachment glycoprotein interacts with a cellular B class ephrin protein receptor triggering conformational alterations leading to the activation of the viral fusion(F) glycoprotein. The analysis of monoclonal antibody(mAb) reactivity with G has revealed measurable alterations in the antigenic structure of the glycoprotein following its binding interaction with receptor. These observations only appear to occur with full-length native G glycoprotein,which is a tetrameric oligomer,and not with soluble forms of G(sG) ,which are disulfide-linked dimers. Single amino acid mutations in a heptad repeat-like structure within the stalk domain of G can disrupt its association with F and subsequent membrane fusion promotion activity. Notably,these mutants of G also appear to confer a post-receptor bound conformation implicating the stalk domain as an important element in the G glycoprotein's structure and functional relationship with F. Together,these observations suggest fusion is dependent on a specific interaction between the F and G glycoproteins of the henipaviruses. Further,receptor binding induces measurable changes in the G glycoprotein that appear to be greatest in respect to the interactions between the pairs of dimers comprising its native tetrameric structure. These receptor-induced conformational changes may be associated with the G glycoprotein's promotion of the fusion activity of F.
文摘The radiological characterization is to determine the type, the distribution and the radioactivity of the radionuclide in the reactor by investigation of the information, instrumentation detection, sampling analyses and theoretical calculation. It is used for determination of the decommissioning implementation option and radiological protection measure of the workers. After completion of the decommissioning it is used for determination of the site release. The radiological characterization should go through whole decommissioning process, which includes: the collection and review of historical file, the performing calculation of radionuclide inventory in the reactor, in situ measurement, sampling analyses, the review and evaluation of the data obtained and the comparison of calculated result with measured date etc.. The special attention should be paid to the radiological characterization information from the key part of reactor in decommissioning end state. The sampling from the "hot spot" should not be lost; the number of the sampling should be reasonable based on reliable statistics. The radioactivity density for site release should comply with the guide, standard and regulation of International Atomic Energy Agency and China.
基金supported by the National Natural Science Foundation of China (Grant No.60936001)
文摘In this paper,the possibility of the monatomic chain (MC) formation for ZnO material was studied by molecular dynamics (MD) simulation.The process of MC formation and the effects of temperature,strain rate and size were studied extensively.The tensile process can be divided to be five stages and the ZnO diatomic chain (DC) can be found.The MD results show that most atoms in MC came from the original surface of ZnO nanowires (NWs).Temperature and strain rate are two important factors affecting the process,and both high temperature and low strain rate in a certain range would be beneficial to the formation of DC.Moreover,the effects of strain rate and temperature could attribute to the Arrhenius model and the energy release mechanism.Furthermore,multi-shell structure was found for the samples under tensile strain and the layer-layer distance was about 3.Our studies based on density functional theory showed that the most stable structure of ZnO DC was confirmed to be linear,and the I-V curve was also got using ATK.
基金financially supported by the National Natural Science Foundation of China(21701122 and 21871206)。
文摘The rational design and synthesis of hierarchically hollow nanostructures with controlled spatial architecture and composition are significant in electrocatalysis owing to their abundant active sites and the expedited electron/mass transfer.Electrocatalytic nitrate reduction to ammonia is of great interest from the points of environmental protection and energy saving.However,the development of this technology is hindered by the lack of efficient nitrate-toammonia electrocatalysts and the kinetically sluggish oxygen evolution reaction at the anode.Herein,a novel self-template conversion method was developed for the synthesis of Co3O4@Ni O hierarchical nanotubes(Co3O4@Ni O HNTs)with Ni O porous nanosheets assembled on Co3O4nanotubes.The as-obtained Co3O4@Ni O HNTs exhibited an outstanding performance for both the cathodic nitrate electroreduction to ammonia reaction and the anodic tetrahydroisoquinolines(THIQs)semi-dehydrogenation to dihydroisoquinolines(DHIQs).Importantly,a two-electrode system of Co3O4@Ni O HNTs||Co3O4@Ni O HNTs was constructed for the simultaneous synthesis of ammonia and DHIQs with high selectivity and robust stability.
文摘A general method is developed to prepare durable hybrid nanocatalysts by nanostructuring the surface of gold wires via simple alloying and dealloying. The resulting nanoporous gold/Au (NPG/Au) wire catalysts possess nanoporous skins with their thicknesses on robust metal wires specified in a highly controllable manner. As a demonstration, the as-obtained NPG/Au was shown to be a highly active, chemo-selective, and recyclable catalyst for the reduction of nitro com- pounds and azides using organosilanes as reducing agents.
文摘A highly sensitive in-situ turbidity sensor with the low power consumption was proposed and evaluated in this study. To meet the practical requirements of the in-situ detection, we have designed the light scattering path, watertight mechanical structure, and ultra-weak scattering light detecting method. Experiments showed that the sensor had a sensitivity of 0.0076 FTU with the concentration range of 0 - 25 FTU and the R-square of 0.9999. The sensor could withstand the water pressure in depth of 1000m and had the low power consumption in the active mode 10.4mA, sleep mode 65 pA with a supply voltage of 8.4V. Southern China Sea buoy experiments indicated that the sensor could work well in the actual in-situ environment. In comparison with sensors of other companies, our sensor had relatively more comprehensive performance.
基金Supported by the National Basic Research Program of China under Grant No. 2011CB606405the Hunan Provincial Natural Science Foundation of China under Grant No. 11JJ4002the Fundamental Research Funds for the Central Universities
文摘Using the first-principles band-structure method and a special quasirandom structure(SQS) approach,we have systematically calculated the alloy bowing coefficients and the nature band offsets of SnxZn1-x Te alloys.We show that the bowing coefficients and band gaps of these alloys are sensitively composition dependent.Due to wave functions full overlapping and delocalization of the Sn outermost p orbits and Zn s orbits,the coupling between these states is very strong,resulting in a significant downshift of conduction band edge with the increase of the Sn concentration x,While the valence band edge keeps almost unchanged compared with that of the binary ZnTe,thus improving the possibility for ambipolar-doping.
文摘Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and opening from the perspective of state transformation, and explores the deep-level causes of the difficulties contemporary China is facing in its economic and social development. It argues that the Chinese state has gradually become a developmental state with a new form, which has played an important role in promoting the development of China's economy and society but meanwhile has brought some negative impacts. China has made many efforts to go beyond the developmental state, and achieved notable success in various aspects since 2002, but there are still many problems, especially when struck by the 2008 world financial crisis; the negative impacts of the developmental state are gradually emerging. Moreover, the Chinese government still tends to sidestep some systemic and structural problems, and some policies are in fact consolidating the dominance of the old system, which will inevitably increase the difficulties for the Chinese state to go beyond the developmental state.