World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. ...World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island(UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band 6 of two Landsat TM/ETM\++ images of 1989 and 2000 to observe the UHI changes over 11-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen's urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index(URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu Island. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and using light-colored, highly reflective roof and paving materials should be included in the plans of the city planers, environmental managers and other decision-makers to improve the overall urban environment in the future.展开更多
Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an...Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (AlFeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0 07% (mass fraction).展开更多
A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) w...A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.展开更多
In order to establish a new method for making cellulose and lignin from Masson pine, a high boiling solvent(HBS) pulping process with an aqueous solvent of 1,4-butanediol was investigated. Masson pine chips were pulpe...In order to establish a new method for making cellulose and lignin from Masson pine, a high boiling solvent(HBS) pulping process with an aqueous solvent of 1,4-butanediol was investigated. Masson pine chips were pulped with a 70%—90% aqueous solution of 1,4-butanediol containing a small amount of a catalyst at 200—220 ℃ for 60—180 min. HBS Masson pine cellulose is suitable for making paper. Water-insoluble HBS lignin was separated from the liquor reaction mixture by water precipitation. The recovered high boiling solvent(RHBS) is able to be recycled as a pulping solvent, indicating that the HBS method is a pulping process of Masson pine which is energy saving, resources saving and pollution free. HBS lignin has a better chemical reactivity and a lower ash content than lignin sulfonate.展开更多
In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nano...In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.展开更多
The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found...The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found distributed on twin planes of marten-site and dislocation places. Retained austenite was found sheared into martensite and nano-carbide separated at the same time. In addition, the tempering martensite was fine-grained. The stated changes of HSS evidently improve the lifespan of HSS cutter and fully show the advantages of nano-structure. The cryogenic treatment of HSS also improves the roughness of HSS cutter (decrease Ra number by about 50%) and greatly increases the wear resistance of HSS cutter. Further experiments on the wear characteristic of HSS cutter supported the findings mentioned above. The stated HSS treatment technology would implement nano-structure of traditional tool steel through phase change. It could be a new method to improve the performance of HSS cutter.展开更多
Nanocrystalline nickel was synthesize d by direct current electrodeposition from a modified Watts-type bath. X-ray diffraction and transmission electron microscope were used to characterize the microstructure of nicke...Nanocrystalline nickel was synthesize d by direct current electrodeposition from a modified Watts-type bath. X-ray diffraction and transmission electron microscope were used to characterize the microstructure of nickel deposits. The results show that nanocrytalline nickel with grain sizes in the range 20~50nm can be synthesized from saccharin-containing Watts-type baths with current density range 5~30A/dm2. There existed preferred orientation in the deposits and it changed progressively from a (200) fibre texture to a (111) (200) double fibre texture as saccharin concentration increased. The hardness of the deposits increased prominently as grain size decreased to nanometer range.展开更多
A one dimension solid and a two dimension solid consisting of polyoxoanions bridged by {CoO 3N 2} and {CoO 4} groups respectively have been synthesized by the hydrothermal method and structurally characterized by...A one dimension solid and a two dimension solid consisting of polyoxoanions bridged by {CoO 3N 2} and {CoO 4} groups respectively have been synthesized by the hydrothermal method and structurally characterized by X Ray crystallography. Each structure has the [(PO 4) 4Mo 6O 15 ] 12- cluster that is commonly observed in many molybdophosphates. In compound 1, [(PO 4) 4Mo 6O 15 ] 12- clusters are linked by {CoO 3N 2} groups to form a chain like structure, and the chains are hydrogen bonded into a network. Compound 2 is a layer structure with channnels constructed from [(PO 4) 4Mo 6O 15 ] 12- clusters and {CoO 4} groups, the organic molecules and the lattice water molecules are distributed disorderly in the interlamellar region and form strong hydrogen bonds with inorganic framework. The IR and the fluorescent spectra were investigated and discussed.展开更多
The influence of Fe2O3 impurity on the crystalline structure of cordierite synthesized from waste aluminum slag is discussed. XRD and SEM techniques were employed to characterize the crystalline structure and micros...The influence of Fe2O3 impurity on the crystalline structure of cordierite synthesized from waste aluminum slag is discussed. XRD and SEM techniques were employed to characterize the crystalline structure and microstructure of each specimen. Philips X’pert plus software was used to determine the lattice parameters of each specimen. The results show that the Fe2O3 content of 0.8~1.6wt% is beneficial to the formation of cordierite, with the cordierite amount reaching 90wt%. So 0.8~1.6wt% is considered as the allowable Fe2O3 content in the specimens and 0.8wt% is determined to be the best after overall analysis. Plus software analysis shows that the cordierite in each specimen has the same symmetrical hexagonal structure as the single crystal, and the lattice parameters as well as the lattice dimensions change slightly.展开更多
The complete and incomplete aggregation-annihilation processes are investigated with the method of generating function, and the scale exponents are obtained exactly. We find that the scale exponents of incomplete aggr...The complete and incomplete aggregation-annihilation processes are investigated with the method of generating function, and the scale exponents are obtained exactly. We find that the scale exponents of incomplete aggregation-annihilation process are different from the previous exponents obtained by different methods. The time dependence of the total number of clusters and the total mass of clusters are analytically obtained.展开更多
The title complex NiL(py)3, where H2L = N-salicylaldehyde-N-phenoxyacetyl hydrazine, was prepared and characterized by X-ray diffraction. The single crystal of the title compound, Ni(C15H12N2O3)(C5H5N)3, is of monocli...The title complex NiL(py)3, where H2L = N-salicylaldehyde-N-phenoxyacetyl hydrazine, was prepared and characterized by X-ray diffraction. The single crystal of the title compound, Ni(C15H12N2O3)(C5H5N)3, is of monoclinic, space group P21/c with a = 11.900(1), b = 9.6855(7), c = 23.658(2) , b = 92.357(2)? V = 2724.5(4) 3, Z = 4, F(000) = 1176, Dc = 1.376 g/cm3, ?= 0.753 mm-1, R = 0.0332 and wR = 0.0820. The coordination polyhedron around the nickel atom is an elongated octahedron. The basal plane consists of one phenol oxygen, one amine carbonyl oxygen and one hydrazine nitrogen atoms from the ligand L2- and one nitrogen atom from one coordinated pyridine ligand, while the axial sites are occupied by two nitrogen atoms of two coordinated pyridine ligands.展开更多
Two title compounds, 4,4?diformyl-diphenoxyethane (compound 1, C16H14O4) and 4,4?4创-triformyl-triphenoxytriethylamine (compound 2, C27H27NO6), were synthesized by condensation of 4-hydroxybenzaldehyde with 1,2-dichlo...Two title compounds, 4,4?diformyl-diphenoxyethane (compound 1, C16H14O4) and 4,4?4创-triformyl-triphenoxytriethylamine (compound 2, C27H27NO6), were synthesized by condensation of 4-hydroxybenzaldehyde with 1,2-dichloroethane and tris(2-chloroethyl)amine, respectively in dimethyl formamide in the presence of anhydrous potassium carbonate. The crystal data are: monoclinic, P21/c, a = 7.571(2), b = 12.608(3), c = 7.357(2) ? b = 105.823(6)? V = 675.7(2) 3, Mr = 270.3, Z = 2, Dc = 1.328 g/cm3, F(000) = 284, m(MoKa) = 0.096 mm-1, R = 0.0537 and wR = 0.2189 for compound 1; and monoclinic, P21/n, a = 11.7162(6), b = 9.0042(6), c = 22.908(2) ? b = 99.505(1)? V = 2383.5(3) ?, Mr = 461.50, Z = 4, Dc = 1.286 g/cm3, F(000)= 976, m(MoKa) = 0.091 mm-1, R = 0.0464 and wR = 0.1462 for compound 2. The molecule of compound 1 (dialdehyde) is located at the crystallographic inversion center nearby the midpoint of C(8)C(8A) single bond. The three chains in the molecule of compound 2 (trialdehyde) are of non-crystallographic pseudo-C3 symmetry, and each of them is quite planar.展开更多
We propose a scheme to generate entangled coherent states for the vibrational modes of N trapped ions.In the scheme the first ion is sequentially excited by two travelling wave laser fields tuned to the ion transition...We propose a scheme to generate entangled coherent states for the vibrational modes of N trapped ions.In the scheme the first ion is sequentially excited by two travelling wave laser fields tuned to the ion transition. The scheme works in the strong-excitation regime, which is of experimental importance in view of decoherence.展开更多
A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indica...A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indicates that the compound crystallizes in the triclinic system, space group P1, with a = 8.1500(16), b = 8.5100(17), c = 9.0500(18) ?, α = 72.77(3), β = 65.50(3), γ = 77.22(3)o, V = 542.02(19) ?3, Z = 2, Dc = 1.505 g/cm3, F(000) = 253, Mr = 245.69, μ(MoKα) = 0.655 mm-1, R = 0.0733 and wR = 0.1703 for 1673 observed reflections (I > 2σ(I)). The compound is characteristic of a zigzag chain-like framework built up of ta bridge and (Imid)4Mn group. The 1-D frameworks are held together by H-bonds between the dangling N–H donors from imid and O acceptors from ta.展开更多
A scheme is presented for generating W states for three o()four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, result...A scheme is presented for generating W states for three o()four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence.展开更多
We describe the Greenberger-Horne-Zeilinger (GHZ) paradox in the multi-mode Schroedinger cat states.We also show that the multi-mode cat states violate the Bell's inequality by an amount that grows exponentially w...We describe the Greenberger-Horne-Zeilinger (GHZ) paradox in the multi-mode Schroedinger cat states.We also show that the multi-mode cat states violate the Bell's inequality by an amount that grows exponentially with number of modes. The test of quantum nonlocality is based on parity measurement and displacement operation, which are experimentally feasible. We also describe a scheme for the generation of the cat states in cavity QED.展开更多
Fusion of images with different spatial and spectral resolutions can improve the visualization of the images. Many fusion techniques have been developed to improve the spectral fidelity and/or spatial texture quality ...Fusion of images with different spatial and spectral resolutions can improve the visualization of the images. Many fusion techniques have been developed to improve the spectral fidelity and/or spatial texture quality of fused imagery. Of them, a recently proposed algorithm, the SFIM (Smoothing Filter-based Intensity Modulation), is known for its high spectral fidelity and simplicity. However, the study and evaluation of the algorithm were only based on spectral and spatial criteria. Therefore, this paper aims to further study the classification accuracy of the SFIM-fused imagery. Three other simple fusion algorithms, High-Pass Filter (HPF), Multiplication (MLT), and Modified Brovey (MB), have been employed for further evaluation of the SFIM. The study is based on a Landsat-7 ETM+ sub-scene covering the urban fringe of southeastern Fuzhou City of China.The effectiveness of the algorithm has been evaluated on the basis of spectral fidelity, high spatial frequency information absorption, and classification accuracy. The study reveals that the difference in smoothing filter kernel sizes used in producing the SFIM-fused images can affect the classification accuracy. Compared with three other algorithms, the SFIM transform is the best method in retaining spectral information of the original image and in getting best classification results.展开更多
A scheme is suggested for the generation of multi-atom maximally entangled states with a cavity in a thermalstate. In this scheme several appropriately prepared two-level atoms are simultaneously sent through the nonr...A scheme is suggested for the generation of multi-atom maximally entangled states with a cavity in a thermalstate. In this scheme several appropriately prepared two-level atoms are simultaneously sent through the nonresonantcavity. We divide the whole atom-cavity interaction time into two equal parts. At the end of the first part a π pulse isapplied to the atoms using a classical field. Then the photon-number-dependent shifts on the atomic states are cancelledand the atomic system finally evolves to a maximally entangled state.展开更多
AIM: The survival rate of patients with stomach cancer is used to evaluate the effects of treatments. The short- and mid-term survival of patients on the present level of treatments can be described by calculating 1- ...AIM: The survival rate of patients with stomach cancer is used to evaluate the effects of treatments. The short- and mid-term survival of patients on the present level of treatments can be described by calculating 1- to 5-year survival rates. The aims of this study were to document patterns of survival after treatments for stomach cancer in Changle city and analyze whether the stage of cancer and the way of treatment impacted on survival of patients or not. METHODS: A total number of 745 patients with stomach cancer reported in the Changle Cancer Registry from 1993 to 1998 were investigated with respect to the disease condition, the way of treatment and survival time. 1- to 5- year survival rates were estimated by using life-table method. RESULTS: The 1- to 5-year survival rates in the patients with stomach cancer in Changle city were 54.23%, 41.77%, 37.95%, 33.98% and 30.47%, respectively. The 1- to 5-year survival rates in stageIor II group were 3, 6.1, 7.4, 8.9 and 9.8 times as high as those in stage III or IV group, respectively. The 1- to 5-year survival rates in operation group were 3.5, 8.7, 11.2, 11.7 and 19 times as high as those in no operation group, respectively. For the patients with stage III or IV stomach cancer the 1-year survival rate in operation group was 3 times as high as that in no operation group and 2- year survival rate in operation group was 11.9 times as high as that in no operation group. For the patients wibh stage III or 1V stomach cancer, the differences of the survival rates average survival times between total gastrectomy and partial gastrectomy were not significant and the median survival times in these 2 groups were 8 mo and 9 mo, respectively. CONCLUSION: Mid-term survival rates of patients with stomach cancer in Changle city are low. Stage of cancer is an important factor influencing survival of patients with stomach cancer. Surgery is an effective treatment for the patients with stage IV cancer and can raise short- and mid-term survival rates. Total gastrectomy should not be encouraged for the patients with late stage of cancer.展开更多
A binuclear complex including ferrocenyl, Cu2{Fe(C5H5)[C5H4CH2N(CH3)2]}2 (CH3COO)4, was synthesized and characterized by X-ray diffraction. The title complex crystallizes in triclinic, space group P with a = 8.2779(8...A binuclear complex including ferrocenyl, Cu2{Fe(C5H5)[C5H4CH2N(CH3)2]}2 (CH3COO)4, was synthesized and characterized by X-ray diffraction. The title complex crystallizes in triclinic, space group P with a = 8.2779(8), b = 9.4830(8), c = 12.262(1) ? = 81.079(5), b = 80.620(4), g = 78.960(4), V = 924.4(1) 3, Z = 1, C34H46Cu2Fe2N2O8, Mr = 849.51, Dc = 1.526 g/cm3, l(MoK) = 0.71073 ? ?= 1.954 mm-1, F(000) = 438, R = 0.0297 and wR = 0.0901. Both cyclopentadienyl rings in each dmaf (dmaf = (dimethylaminomethyl)ferrocene, Fe(C5H5)- [C5H4CH2N(CH3)2]) have an eclipsed conformation. The binuclear molecule has a crystallographic centrosymmetry; four acetates and two Cu atoms form a cage structure with the distance between two neighboring Cu atoms of 2.655(1) .展开更多
文摘World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island(UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band 6 of two Landsat TM/ETM\++ images of 1989 and 2000 to observe the UHI changes over 11-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen's urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index(URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu Island. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and using light-colored, highly reflective roof and paving materials should be included in the plans of the city planers, environmental managers and other decision-makers to improve the overall urban environment in the future.
文摘Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (AlFeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0 07% (mass fraction).
文摘A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.
基金Supported by the Science and Technology Fund of Fujian Education Departm ent(No.JB 0 2 0 5 8) ,Scientific Develop-ment Fund of Econom y and Trade Comm ission of Fujian Province(No.2 0 0 30 7) ,Science and Technology Department Fund ofFuzhou City(No.
文摘In order to establish a new method for making cellulose and lignin from Masson pine, a high boiling solvent(HBS) pulping process with an aqueous solvent of 1,4-butanediol was investigated. Masson pine chips were pulped with a 70%—90% aqueous solution of 1,4-butanediol containing a small amount of a catalyst at 200—220 ℃ for 60—180 min. HBS Masson pine cellulose is suitable for making paper. Water-insoluble HBS lignin was separated from the liquor reaction mixture by water precipitation. The recovered high boiling solvent(RHBS) is able to be recycled as a pulping solvent, indicating that the HBS method is a pulping process of Masson pine which is energy saving, resources saving and pollution free. HBS lignin has a better chemical reactivity and a lower ash content than lignin sulfonate.
基金This work was supported by the Foundation of Education Committee of Fujian Province (No. JA03005), and Science and Technology Development Foundation of Fuzhou University
文摘In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.
文摘The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found distributed on twin planes of marten-site and dislocation places. Retained austenite was found sheared into martensite and nano-carbide separated at the same time. In addition, the tempering martensite was fine-grained. The stated changes of HSS evidently improve the lifespan of HSS cutter and fully show the advantages of nano-structure. The cryogenic treatment of HSS also improves the roughness of HSS cutter (decrease Ra number by about 50%) and greatly increases the wear resistance of HSS cutter. Further experiments on the wear characteristic of HSS cutter supported the findings mentioned above. The stated HSS treatment technology would implement nano-structure of traditional tool steel through phase change. It could be a new method to improve the performance of HSS cutter.
基金supported by the Fujian provincial Nature Science Foundation of China(Grant No.E0410011)
文摘Nanocrystalline nickel was synthesize d by direct current electrodeposition from a modified Watts-type bath. X-ray diffraction and transmission electron microscope were used to characterize the microstructure of nickel deposits. The results show that nanocrytalline nickel with grain sizes in the range 20~50nm can be synthesized from saccharin-containing Watts-type baths with current density range 5~30A/dm2. There existed preferred orientation in the deposits and it changed progressively from a (200) fibre texture to a (111) (200) double fibre texture as saccharin concentration increased. The hardness of the deposits increased prominently as grain size decreased to nanometer range.
文摘A one dimension solid and a two dimension solid consisting of polyoxoanions bridged by {CoO 3N 2} and {CoO 4} groups respectively have been synthesized by the hydrothermal method and structurally characterized by X Ray crystallography. Each structure has the [(PO 4) 4Mo 6O 15 ] 12- cluster that is commonly observed in many molybdophosphates. In compound 1, [(PO 4) 4Mo 6O 15 ] 12- clusters are linked by {CoO 3N 2} groups to form a chain like structure, and the chains are hydrogen bonded into a network. Compound 2 is a layer structure with channnels constructed from [(PO 4) 4Mo 6O 15 ] 12- clusters and {CoO 4} groups, the organic molecules and the lattice water molecules are distributed disorderly in the interlamellar region and form strong hydrogen bonds with inorganic framework. The IR and the fluorescent spectra were investigated and discussed.
基金This work was supported by the '863' Project (2003AA322020)
文摘The influence of Fe2O3 impurity on the crystalline structure of cordierite synthesized from waste aluminum slag is discussed. XRD and SEM techniques were employed to characterize the crystalline structure and microstructure of each specimen. Philips X’pert plus software was used to determine the lattice parameters of each specimen. The results show that the Fe2O3 content of 0.8~1.6wt% is beneficial to the formation of cordierite, with the cordierite amount reaching 90wt%. So 0.8~1.6wt% is considered as the allowable Fe2O3 content in the specimens and 0.8wt% is determined to be the best after overall analysis. Plus software analysis shows that the cordierite in each specimen has the same symmetrical hexagonal structure as the single crystal, and the lattice parameters as well as the lattice dimensions change slightly.
文摘The complete and incomplete aggregation-annihilation processes are investigated with the method of generating function, and the scale exponents are obtained exactly. We find that the scale exponents of incomplete aggregation-annihilation process are different from the previous exponents obtained by different methods. The time dependence of the total number of clusters and the total mass of clusters are analytically obtained.
基金This work was supported by the National Natural Science Foundation of China (No. 20171012) and the Natural Science Foundation of Fujian province (No. E0110010)
文摘The title complex NiL(py)3, where H2L = N-salicylaldehyde-N-phenoxyacetyl hydrazine, was prepared and characterized by X-ray diffraction. The single crystal of the title compound, Ni(C15H12N2O3)(C5H5N)3, is of monoclinic, space group P21/c with a = 11.900(1), b = 9.6855(7), c = 23.658(2) , b = 92.357(2)? V = 2724.5(4) 3, Z = 4, F(000) = 1176, Dc = 1.376 g/cm3, ?= 0.753 mm-1, R = 0.0332 and wR = 0.0820. The coordination polyhedron around the nickel atom is an elongated octahedron. The basal plane consists of one phenol oxygen, one amine carbonyl oxygen and one hydrazine nitrogen atoms from the ligand L2- and one nitrogen atom from one coordinated pyridine ligand, while the axial sites are occupied by two nitrogen atoms of two coordinated pyridine ligands.
基金The authors thank the financial support of the Natural Science Foundation of Fujian Province (No. E0110010)
文摘Two title compounds, 4,4?diformyl-diphenoxyethane (compound 1, C16H14O4) and 4,4?4创-triformyl-triphenoxytriethylamine (compound 2, C27H27NO6), were synthesized by condensation of 4-hydroxybenzaldehyde with 1,2-dichloroethane and tris(2-chloroethyl)amine, respectively in dimethyl formamide in the presence of anhydrous potassium carbonate. The crystal data are: monoclinic, P21/c, a = 7.571(2), b = 12.608(3), c = 7.357(2) ? b = 105.823(6)? V = 675.7(2) 3, Mr = 270.3, Z = 2, Dc = 1.328 g/cm3, F(000) = 284, m(MoKa) = 0.096 mm-1, R = 0.0537 and wR = 0.2189 for compound 1; and monoclinic, P21/n, a = 11.7162(6), b = 9.0042(6), c = 22.908(2) ? b = 99.505(1)? V = 2383.5(3) ?, Mr = 461.50, Z = 4, Dc = 1.286 g/cm3, F(000)= 976, m(MoKa) = 0.091 mm-1, R = 0.0464 and wR = 0.1462 for compound 2. The molecule of compound 1 (dialdehyde) is located at the crystallographic inversion center nearby the midpoint of C(8)C(8A) single bond. The three chains in the molecule of compound 2 (trialdehyde) are of non-crystallographic pseudo-C3 symmetry, and each of them is quite planar.
文摘We propose a scheme to generate entangled coherent states for the vibrational modes of N trapped ions.In the scheme the first ion is sequentially excited by two travelling wave laser fields tuned to the ion transition. The scheme works in the strong-excitation regime, which is of experimental importance in view of decoherence.
基金This project was supported by the Key Project of Chinese Ministry of Education and the Natural Science Foundation of Yunnan Province (2002E0004Q)
文摘A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indicates that the compound crystallizes in the triclinic system, space group P1, with a = 8.1500(16), b = 8.5100(17), c = 9.0500(18) ?, α = 72.77(3), β = 65.50(3), γ = 77.22(3)o, V = 542.02(19) ?3, Z = 2, Dc = 1.505 g/cm3, F(000) = 253, Mr = 245.69, μ(MoKα) = 0.655 mm-1, R = 0.0733 and wR = 0.1703 for 1673 observed reflections (I > 2σ(I)). The compound is characteristic of a zigzag chain-like framework built up of ta bridge and (Imid)4Mn group. The 1-D frameworks are held together by H-bonds between the dangling N–H donors from imid and O acceptors from ta.
文摘A scheme is presented for generating W states for three o()four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence.
文摘We describe the Greenberger-Horne-Zeilinger (GHZ) paradox in the multi-mode Schroedinger cat states.We also show that the multi-mode cat states violate the Bell's inequality by an amount that grows exponentially with number of modes. The test of quantum nonlocality is based on parity measurement and displacement operation, which are experimentally feasible. We also describe a scheme for the generation of the cat states in cavity QED.
基金Under the auspices of the National Natural Science Foundation of China(No.40371107) and Ministry of Education of China
文摘Fusion of images with different spatial and spectral resolutions can improve the visualization of the images. Many fusion techniques have been developed to improve the spectral fidelity and/or spatial texture quality of fused imagery. Of them, a recently proposed algorithm, the SFIM (Smoothing Filter-based Intensity Modulation), is known for its high spectral fidelity and simplicity. However, the study and evaluation of the algorithm were only based on spectral and spatial criteria. Therefore, this paper aims to further study the classification accuracy of the SFIM-fused imagery. Three other simple fusion algorithms, High-Pass Filter (HPF), Multiplication (MLT), and Modified Brovey (MB), have been employed for further evaluation of the SFIM. The study is based on a Landsat-7 ETM+ sub-scene covering the urban fringe of southeastern Fuzhou City of China.The effectiveness of the algorithm has been evaluated on the basis of spectral fidelity, high spatial frequency information absorption, and classification accuracy. The study reveals that the difference in smoothing filter kernel sizes used in producing the SFIM-fused images can affect the classification accuracy. Compared with three other algorithms, the SFIM transform is the best method in retaining spectral information of the original image and in getting best classification results.
基金国家自然科学基金,福建省自然科学基金,Fujian Provincial Natural Science Foundation of China,福州大学校科研和教改项目
文摘A scheme is suggested for the generation of multi-atom maximally entangled states with a cavity in a thermalstate. In this scheme several appropriately prepared two-level atoms are simultaneously sent through the nonresonantcavity. We divide the whole atom-cavity interaction time into two equal parts. At the end of the first part a π pulse isapplied to the atoms using a classical field. Then the photon-number-dependent shifts on the atomic states are cancelledand the atomic system finally evolves to a maximally entangled state.
基金Supported by the Natural Science Foundation of Fujian,No.A0210012
文摘AIM: The survival rate of patients with stomach cancer is used to evaluate the effects of treatments. The short- and mid-term survival of patients on the present level of treatments can be described by calculating 1- to 5-year survival rates. The aims of this study were to document patterns of survival after treatments for stomach cancer in Changle city and analyze whether the stage of cancer and the way of treatment impacted on survival of patients or not. METHODS: A total number of 745 patients with stomach cancer reported in the Changle Cancer Registry from 1993 to 1998 were investigated with respect to the disease condition, the way of treatment and survival time. 1- to 5- year survival rates were estimated by using life-table method. RESULTS: The 1- to 5-year survival rates in the patients with stomach cancer in Changle city were 54.23%, 41.77%, 37.95%, 33.98% and 30.47%, respectively. The 1- to 5-year survival rates in stageIor II group were 3, 6.1, 7.4, 8.9 and 9.8 times as high as those in stage III or IV group, respectively. The 1- to 5-year survival rates in operation group were 3.5, 8.7, 11.2, 11.7 and 19 times as high as those in no operation group, respectively. For the patients with stage III or IV stomach cancer the 1-year survival rate in operation group was 3 times as high as that in no operation group and 2- year survival rate in operation group was 11.9 times as high as that in no operation group. For the patients wibh stage III or 1V stomach cancer, the differences of the survival rates average survival times between total gastrectomy and partial gastrectomy were not significant and the median survival times in these 2 groups were 8 mo and 9 mo, respectively. CONCLUSION: Mid-term survival rates of patients with stomach cancer in Changle city are low. Stage of cancer is an important factor influencing survival of patients with stomach cancer. Surgery is an effective treatment for the patients with stage IV cancer and can raise short- and mid-term survival rates. Total gastrectomy should not be encouraged for the patients with late stage of cancer.
基金The work was supported by the Provincial Education Foundation of Fujian (JA99135) the Test Foundation of Fuzhou University and the foundation of the Department of Chemistry Fuzhou University
文摘A binuclear complex including ferrocenyl, Cu2{Fe(C5H5)[C5H4CH2N(CH3)2]}2 (CH3COO)4, was synthesized and characterized by X-ray diffraction. The title complex crystallizes in triclinic, space group P with a = 8.2779(8), b = 9.4830(8), c = 12.262(1) ? = 81.079(5), b = 80.620(4), g = 78.960(4), V = 924.4(1) 3, Z = 1, C34H46Cu2Fe2N2O8, Mr = 849.51, Dc = 1.526 g/cm3, l(MoK) = 0.71073 ? ?= 1.954 mm-1, F(000) = 438, R = 0.0297 and wR = 0.0901. Both cyclopentadienyl rings in each dmaf (dmaf = (dimethylaminomethyl)ferrocene, Fe(C5H5)- [C5H4CH2N(CH3)2]) have an eclipsed conformation. The binuclear molecule has a crystallographic centrosymmetry; four acetates and two Cu atoms form a cage structure with the distance between two neighboring Cu atoms of 2.655(1) .