The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most s...The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most significant applications of metal oxides is heterogeneous catalysis,which represents a pivotal technology in industrial production on a global scale.Catalysts serve as the primary enabling agents for chemical reactions,and among the plethora of catalysts,metal oxides including magnesium oxide(MgO),ceria(CeO_(2))and titania(TiO_(2)),have been identified to be particularly effective in catalyzing a variety of reactions[1].Theoretical calculations based on density functional theory(DFT)and a multitude of other quantum chemistry methods have proven invaluable in elucidating the mechanisms of metal-oxide-catalyzed reactions,thereby facilitating the design of high-performance catalysts[2].展开更多
This paper presents a fully automatic segmentation method of liver CT scans using fuzzy c-mean clustering and level set. First, the contrast of original image is enhanced to make boundaries clearer;second, a spatial f...This paper presents a fully automatic segmentation method of liver CT scans using fuzzy c-mean clustering and level set. First, the contrast of original image is enhanced to make boundaries clearer;second, a spatial fuzzy c-mean clustering combining with anatomical prior knowledge is employed to extract liver region automatically;thirdly, a distance regularized level set is used for refinement;finally, morphological operations are used as post-processing. The experiment result shows that the method can achieve high accuracy (0.9986) and specificity (0.9989). Comparing with standard level set method, our method is more effective in dealing with over-segmentation problem.展开更多
This article is an addendum to the 2001 paper [1] which investigated an approach to hierarchical clustering based on the level sets of a density function induced on data points in a d-dimensional feature space. We ref...This article is an addendum to the 2001 paper [1] which investigated an approach to hierarchical clustering based on the level sets of a density function induced on data points in a d-dimensional feature space. We refer to this as the “level-sets approach” to hierarchical clustering. The density functions considered in [1] were those formed as the sum of identical radial basis functions centered at the data points, each radial basis function assumed to be continuous, monotone decreasing, convex on every ray, and rising to positive infinity at its center point. Such a framework can be investigated with respect to both the Euclidean (L2) and Manhattan (L1) metrics. The addendum here puts forth some observations and questions about the level-sets approach that go beyond those in [1]. In particular, we detail and ask the following questions. How does the level-sets approach compare with other related approaches? How is the resulting hierarchical clustering affected by the choice of radial basis function? What are the structural properties of a function formed as the sum of radial basis functions? Can the levels-sets approach be theoretically validated? Is there an efficient algorithm to implement the level-sets approach?展开更多
A series of clusters Ni4P are designed to simulate the amorphous alloy Ni80P20. After the cluster models are computed by DFT, several stable structures are gained. Their geometric, electronic and catalytic properties ...A series of clusters Ni4P are designed to simulate the amorphous alloy Ni80P20. After the cluster models are computed by DFT, several stable structures are gained. Their geometric, electronic and catalytic properties have been analyzed and discussed. It is proved that cluster Ni4P can reflect the amorphous alloy Ni80P20 very well from the geometry parameters. We find the deformed triangle dipyramid with quadruplet state （configuration 1^（4）） is the most stable structure for cluster Ni4P, which is the most possible local structure in amorphous alloy Ni80P20. And the transition energy between two isomers with the same multiple state is higher than the one with the different. Bond Ni-P plays a very important role in offering the system stability for cluster Ni4E P is the electron donor, and Ni is the accepter in cluster Ni4P, which is in accordance with the experiment results. The 3d orbital populations and Fermi levels of clusters Ni4 have been decreased with the addition of atom E Based on the research of Fermi levels of clusters Ni4P to approach the Fermi level of H2 and their density of state （DOS）, the highest catalytic active property in cluster Ni4P is owned to configuration 1^（4）.展开更多
Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses ...Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hierarchical clustering technique–average linkage between groups with Pearson correlation for measurement of intervals was employed in the research. The climate of the Balkan Peninsula is transitional between oceanic and continental and also between subtropical and temperate climates. Several major changes in atmospheric circulation over the Balkan Peninsula have happened over the period 1950–2012. There is a serious increase of the influence of the Azores High in the period January–Marchwhich leads to an increase of SLP and enhances oceanic influence. There is an increase of the influence of the north-west extension of the monsoonal low in the period June–September. This leads to more continental climatebut also to more tropical air masses over the Balkan Peninsula. Accordinglythe extent of subtropical climate widens in northern direction. There is an increase of the influence of the Siberian High in the period October–December. This influence covers central and eastern part of the peninsula in October and Novemberand it reaches western parts in December. Thusthe climate becomes more continental.展开更多
This paper proposes two schemes to generate the multi-atom cluster states. The first scheme is based on the interaction of atoms with a highly detuned cavity mode and a classical field, the second scheme is based on t...This paper proposes two schemes to generate the multi-atom cluster states. The first scheme is based on the interaction of atoms with a highly detuned cavity mode and a classical field, the second scheme is based on the interaction of atoms with a cavity mode, strongly driven by a resonant classical field.展开更多
We propose an experimentally feasible scheme for preparing a four-atom cluster state in a thermal cavity. In the scheme, the cavity field is only virtually excited and the photon-number-dependent part in the effective...We propose an experimentally feasible scheme for preparing a four-atom cluster state in a thermal cavity. In the scheme, the cavity field is only virtually excited and the photon-number-dependent part in the effective Hamiltonian is cancelled so that the system is insensitive to the cavity decay and the thermal field. At the same time, the scheme can be generalized to prepare n-atom cluster states with the success probability 100%. In addition, using the four-atom cluster state, we also propose a simpler scheme for implementing a remote-controlled not gate （CNOT） without the Bell states measurement.展开更多
Structural and electronic properties of bimetallic clusters AlnCom with n=1～7 and m=1～2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G...Structural and electronic properties of bimetallic clusters AlnCom with n=1～7 and m=1～2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G level.The charge-induced structural changes in these anions were discussed.In addition,the corresponding total energies,binding energies,adiabatic electron affinities and vertical electron affinity were also presented and discussed.Our predicted vertical ionization potentials are in reasonable agreement with the experimental ionization potentials.Among different AlnCom and AlnCom-anions （n=1～7,m=1～2）,Al4Co,Al6Co,Al4Co-,Al6Co-and Al4Co2-are predicted to be species with high stabilities.展开更多
According to the 2010 China Statistical Yearbook,a total of 12 indicators in the aspects of residents' production,consumption expenditure,and living conditions are selected in order to construct the indicator syst...According to the 2010 China Statistical Yearbook,a total of 12 indicators in the aspects of residents' production,consumption expenditure,and living conditions are selected in order to construct the indicator system of rural development level.Both factor analysis and cluster analysis methods are adopted to compare the current situations of rural development levels in 31 provinces and regions of China.Result of factor analysis shows that the 12 indicators can be classified into 4 factors,such as the income and expenditure factor,the agricultural scale and science and technology factor,the life quality factor,and the agricultural output factor.Moreover,factors affecting the rural development level of China are analyzed.Then,the 31 provinces and regions are divided into 4 categories according to the development levels in rural areas:the first category is Shanghai,Beijing and Zhejiang,which have the highest development level in rural areas;the second category includes Jiangsu,Shandong and Tianjin,which take the 4th to 6th places;the third category is Guangdong,Jilin,Liaoning,Hebei,Fujian,Heilongjiang,Henan,Inner Mongolia,Anhui,Hubei,Hunan and Jiangxi,which rank the 7th-18th;and the fourth category includes Sichuan,Hainan,Ningxia,Shanxi,Guangxi,Shanxi,Xinjiang,Chongqing,Tibet,Yunnan,Gansu,Qinghai and Guizhou,taking the 19th-31st places.展开更多
To understand the spatial difference of agricultural sustainability in Tibet,this paper establishes a comprehensive evaluation model of agricultural sustainability to calculate the score of agricultural sustainability...To understand the spatial difference of agricultural sustainability in Tibet,this paper establishes a comprehensive evaluation model of agricultural sustainability to calculate the score of agricultural sustainability of 7 areas in 2013 in Tibet. By using cluster analysis,this paper conducts the regional evaluation of Tibet's agricultural sustainability. The results show that 7 cities' regional difference of agricultural sustainability was obvious in 2013,the agricultural sustainability index value was 0. 4232- 0. 6937,and the value was in the order of Nyingchi > Lhasa > Shannan > Ali > Shigatse > Qamdo > Nagqu. According to the agricultural sustainable development level,Tibet can be divided into three regions: the first type is the area with the highest level of sustainable development of agriculture,including Nyingchi and Lhasa; the second type is the area with the average level of sustainable development of agriculture,including Shigatse and Shannan; the third type is the area with the low level of sustainable development of agriculture,including Qamdo,Ali and Nagqu.展开更多
We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibration...We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibrational mode in our protocol is only virtually excited so that the system is insensitive to the thermal field. In addition, we only use two levels of ions as qubits and the successful probability may achieve 100%.展开更多
The symmetry of Y<sub>5μ</sub>-deformed fields are classified and the one-particlespectra in two-level model coupled by Y<sub>5μ</sub> fields are discussed.
基金financial support from the National Key R&D Program of China(2021YFB3500700)the National Natural Science Foundation of China(22473042,22003016,and 92145302).
文摘The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most significant applications of metal oxides is heterogeneous catalysis,which represents a pivotal technology in industrial production on a global scale.Catalysts serve as the primary enabling agents for chemical reactions,and among the plethora of catalysts,metal oxides including magnesium oxide(MgO),ceria(CeO_(2))and titania(TiO_(2)),have been identified to be particularly effective in catalyzing a variety of reactions[1].Theoretical calculations based on density functional theory(DFT)and a multitude of other quantum chemistry methods have proven invaluable in elucidating the mechanisms of metal-oxide-catalyzed reactions,thereby facilitating the design of high-performance catalysts[2].
文摘This paper presents a fully automatic segmentation method of liver CT scans using fuzzy c-mean clustering and level set. First, the contrast of original image is enhanced to make boundaries clearer;second, a spatial fuzzy c-mean clustering combining with anatomical prior knowledge is employed to extract liver region automatically;thirdly, a distance regularized level set is used for refinement;finally, morphological operations are used as post-processing. The experiment result shows that the method can achieve high accuracy (0.9986) and specificity (0.9989). Comparing with standard level set method, our method is more effective in dealing with over-segmentation problem.
文摘This article is an addendum to the 2001 paper [1] which investigated an approach to hierarchical clustering based on the level sets of a density function induced on data points in a d-dimensional feature space. We refer to this as the “level-sets approach” to hierarchical clustering. The density functions considered in [1] were those formed as the sum of identical radial basis functions centered at the data points, each radial basis function assumed to be continuous, monotone decreasing, convex on every ray, and rising to positive infinity at its center point. Such a framework can be investigated with respect to both the Euclidean (L2) and Manhattan (L1) metrics. The addendum here puts forth some observations and questions about the level-sets approach that go beyond those in [1]. In particular, we detail and ask the following questions. How does the level-sets approach compare with other related approaches? How is the resulting hierarchical clustering affected by the choice of radial basis function? What are the structural properties of a function formed as the sum of radial basis functions? Can the levels-sets approach be theoretically validated? Is there an efficient algorithm to implement the level-sets approach?
文摘A series of clusters Ni4P are designed to simulate the amorphous alloy Ni80P20. After the cluster models are computed by DFT, several stable structures are gained. Their geometric, electronic and catalytic properties have been analyzed and discussed. It is proved that cluster Ni4P can reflect the amorphous alloy Ni80P20 very well from the geometry parameters. We find the deformed triangle dipyramid with quadruplet state （configuration 1^（4）） is the most stable structure for cluster Ni4P, which is the most possible local structure in amorphous alloy Ni80P20. And the transition energy between two isomers with the same multiple state is higher than the one with the different. Bond Ni-P plays a very important role in offering the system stability for cluster Ni4E P is the electron donor, and Ni is the accepter in cluster Ni4P, which is in accordance with the experiment results. The 3d orbital populations and Fermi levels of clusters Ni4 have been decreased with the addition of atom E Based on the research of Fermi levels of clusters Ni4P to approach the Fermi level of H2 and their density of state （DOS）, the highest catalytic active property in cluster Ni4P is owned to configuration 1^（4）.
文摘Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hierarchical clustering technique–average linkage between groups with Pearson correlation for measurement of intervals was employed in the research. The climate of the Balkan Peninsula is transitional between oceanic and continental and also between subtropical and temperate climates. Several major changes in atmospheric circulation over the Balkan Peninsula have happened over the period 1950–2012. There is a serious increase of the influence of the Azores High in the period January–Marchwhich leads to an increase of SLP and enhances oceanic influence. There is an increase of the influence of the north-west extension of the monsoonal low in the period June–September. This leads to more continental climatebut also to more tropical air masses over the Balkan Peninsula. Accordinglythe extent of subtropical climate widens in northern direction. There is an increase of the influence of the Siberian High in the period October–December. This influence covers central and eastern part of the peninsula in October and Novemberand it reaches western parts in December. Thusthe climate becomes more continental.
文摘This paper proposes two schemes to generate the multi-atom cluster states. The first scheme is based on the interaction of atoms with a highly detuned cavity mode and a classical field, the second scheme is based on the interaction of atoms with a cavity mode, strongly driven by a resonant classical field.
基金Project supported by the National Natural Science Foundation （Grant No 10574022）, and the Funds of the Natural Science of Fujian Province, China （Grant No Z0512006）.
文摘We propose an experimentally feasible scheme for preparing a four-atom cluster state in a thermal cavity. In the scheme, the cavity field is only virtually excited and the photon-number-dependent part in the effective Hamiltonian is cancelled so that the system is insensitive to the cavity decay and the thermal field. At the same time, the scheme can be generalized to prepare n-atom cluster states with the success probability 100%. In addition, using the four-atom cluster state, we also propose a simpler scheme for implementing a remote-controlled not gate （CNOT） without the Bell states measurement.
基金supported by the National Natural Science Foundation of China (20603021)Youth Foundation of Shanxi Province (2007021009)
文摘Structural and electronic properties of bimetallic clusters AlnCom with n=1～7 and m=1～2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G level.The charge-induced structural changes in these anions were discussed.In addition,the corresponding total energies,binding energies,adiabatic electron affinities and vertical electron affinity were also presented and discussed.Our predicted vertical ionization potentials are in reasonable agreement with the experimental ionization potentials.Among different AlnCom and AlnCom-anions （n=1～7,m=1～2）,Al4Co,Al6Co,Al4Co-,Al6Co-and Al4Co2-are predicted to be species with high stabilities.
文摘According to the 2010 China Statistical Yearbook,a total of 12 indicators in the aspects of residents' production,consumption expenditure,and living conditions are selected in order to construct the indicator system of rural development level.Both factor analysis and cluster analysis methods are adopted to compare the current situations of rural development levels in 31 provinces and regions of China.Result of factor analysis shows that the 12 indicators can be classified into 4 factors,such as the income and expenditure factor,the agricultural scale and science and technology factor,the life quality factor,and the agricultural output factor.Moreover,factors affecting the rural development level of China are analyzed.Then,the 31 provinces and regions are divided into 4 categories according to the development levels in rural areas:the first category is Shanghai,Beijing and Zhejiang,which have the highest development level in rural areas;the second category includes Jiangsu,Shandong and Tianjin,which take the 4th to 6th places;the third category is Guangdong,Jilin,Liaoning,Hebei,Fujian,Heilongjiang,Henan,Inner Mongolia,Anhui,Hubei,Hunan and Jiangxi,which rank the 7th-18th;and the fourth category includes Sichuan,Hainan,Ningxia,Shanxi,Guangxi,Shanxi,Xinjiang,Chongqing,Tibet,Yunnan,Gansu,Qinghai and Guizhou,taking the 19th-31st places.
基金Supported by Science and Technology Support Project of Ministry of Science and Technology(2013BAC04B03)Humanities and Social Sciences Research Project of Universities in Tibet Autonomous Region(2013ZJRW02)
文摘To understand the spatial difference of agricultural sustainability in Tibet,this paper establishes a comprehensive evaluation model of agricultural sustainability to calculate the score of agricultural sustainability of 7 areas in 2013 in Tibet. By using cluster analysis,this paper conducts the regional evaluation of Tibet's agricultural sustainability. The results show that 7 cities' regional difference of agricultural sustainability was obvious in 2013,the agricultural sustainability index value was 0. 4232- 0. 6937,and the value was in the order of Nyingchi > Lhasa > Shannan > Ali > Shigatse > Qamdo > Nagqu. According to the agricultural sustainable development level,Tibet can be divided into three regions: the first type is the area with the highest level of sustainable development of agriculture,including Nyingchi and Lhasa; the second type is the area with the average level of sustainable development of agriculture,including Shigatse and Shannan; the third type is the area with the low level of sustainable development of agriculture,including Qamdo,Ali and Nagqu.
基金Project supported by the National Natural Science Foundation of China （Grant No 10574022）, and the Funds of the Natural . Science of Fujian Province, China （Grant No Z0512006）.
文摘We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibrational mode in our protocol is only virtually excited so that the system is insensitive to the thermal field. In addition, we only use two levels of ions as qubits and the successful probability may achieve 100%.
基金The project partly supported by the National Natural Science Foundation of China.
文摘The symmetry of Y<sub>5μ</sub>-deformed fields are classified and the one-particlespectra in two-level model coupled by Y<sub>5μ</sub> fields are discussed.
