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1.
1 Results On the basis of previous work,the general theory,least square methods and computing programs have been proposed and developed,which can separate the two-fold broadening effect caused by crystallite-micro strain,crystallite-stacking faults,strain-faults and which can also separate the three fold broadening effect caused by crystallite-strain-faults in closed-parked hexagonal (CPH) nano-materials.The method is applied to characterize and investigate the microstructure in β-Ni(OH)2 as negative material for nickel/metal (Ni /MH) batteries.The results indicate that in the raw β-Ni(OH)2 there are only two-fold broadening effect of crystallite-faults,however after activation and cycle test three fold broadening effect of crystallite-strain-faults is available.  相似文献   

2.
1 Results Tailored monomers based on the activated esters of 2,5-dibromobenzoic (sulfonic) acid derivatives, the 3-substituted 2,5-dibromothiophenes, the 9-substituted 2,7-dibromocarbazoles, and on the brominated 1,10-phenanthrolines suitable for Suzuki, Yamamoto or Grignard metathesis (GRIM) coupling reactions were synthesized and characterized by melting point, elemental analysis, 1H NMR, FTIR and TLC. The Horner-Wadsworth-Emmons reaction mechanism was utilized for the preparation of the 3-[2-(pyren-1-yl)vinyl]- or 3-[2-(quinolin-1-yl)vinyl]-2,5-dibromothiophenes. 4-Nitrophenol or N-hydroxysuccinimide were used for the preparation of activated esters. The Cadogan ring closure was utilized for the synthesis of 2,7-dibromocarbazole derivatives. A monomer with β-diketone structure was prepared and characterized as well. 1,10-Phenanthroline (phen) is a typical β-deficient aromatic compound and experience (and literature) advises that simple bromination is poor and nonselective. Of course, bromo derivatives can be obtained by the Skraup synthesis, but the low-yield and multi-step procedure is tedious. There are two main reasonable procedures available at present for the synthesis of 3,8-dibromo-1,10-phenanthroline. The methods utilize either phen monohydrochloride monohydrate for bromination or phen with addition of pyridine and sulfur chloride S2Cl2. We have found in our laboratory that the replacement of sulfur chloride by sulfur dichloride SCl2 and the use of phen monohydrate gives the possibility to prepare 3-bromo-, 3,8-dibromo-, 3,5,8-tribromo- and 3,5,6,8-tetrabromo-1,10-phenanthrolines in reasonable yields, and these derivatives can be separated by crystallization or by column chromatography.  相似文献   

3.
Spherical Nano-scale nickel hydroxide was prepared through precipitaition transmutation method by controlling the transmutation conditions in this paper.The measurement results of XRD and TEM indicate that the crystallization of the nano-Scale nickel hydroxide is β-style and its shape is spherical with a diameter of 40-70 nanometer.The adulteration experiment shows that the adulteration ratio of nono-scale Ni(OH)2 in common spherical micrometer-scale Ni(OH)2 exists a optimal value(1:9) And at this point,the utilization ratio of Ni(OH)2 in electrodes can be raised by 10%,and the nono-Scale nickel hydroxide with sphericity shape shows a better adulteration performance than that with needle shapge.  相似文献   

4.
A GF (p) elliptic curve cryptographic coprocessor is proposed and implemented on Field Programmable Gate Array (FPGA). The focus of the coprocessor is on the most critical, complicated and time-consuming point multiplications. The technique of coordinates conversion and fast multiplication algorithm of two large integers are utilized to avoid frequent inversions and to accelerate the field multiplications used in point multiplications. The characteristic of hardware parallelism is considered in the implementation of point multiplications. The coprocessor implemented on XILINX XC2V3000 computes a point multiplication for an arbitrarypoint on a curve defined over GF(2^192-2^64-1) with the frequency of 10 MHz in 4.40 ms in the average case and 5.74ms in the worst case. At the same circumstance, the coprocessor implemented on XILINX XC2V4000 takes 2.2 ms in the average case and 2.88 ms in the worst case.  相似文献   

5.
The k-means clustering algorithm is one of the most commonly used algorithms for clustering analysis. The traditional k-means algorithm is, however, inefficient while working on large numbers of data sets and improving the algorithm efficiency remains a problem. This paper focuses on the efficiency issues of cluster algorithms. A refined initial cluster centers method is designed to reduce the number of iterative procedures in the algorithm. A parallel k-means algorithm is also studied for the problem of the operation limitation of a single processor machine when given huge data sets. The analytical results demonstrate that these improvements can greatly enhance the efficiency of the k-means algorithm, i.e., allow the grouping of a large number of data sets more accurately and more quickly. The analysis has theoretical and practical importance for work on the improvement and parallelism of cluster algorithms.  相似文献   

6.
To examine the community structure of β-Proteobacterial ammonia-oxidizing bacteria (AOB) in prawn farm sediment, the 16S rRNA gene library was constructed with β-Proteobacterial AOB-specific primers. The library was screened by PCR-restriction fragment length polymorphism (RFLP) analysis and clones with unique RFLP patterns were sequenced. Two groups of β-Proteobacterial AOB, the Nitrosomonas and the Nitrosospira, were detected. The Nitrosomonas occupied an absolute dominant position, accounting for more than 90% of total clones in the clone library, while the Nitrosospira accounting for 5.48%. Nitrosomonas-affiliated clones were grouped into the Nitrosomonas marina and the Nitrosomonas sp. Nm143 clusters, and Nitrosospira-affiliated clones were grouped into the Nitrosospira cluster 1. No other clusters of β-Proteobacterial AOB were found. The results enriched our knowledge of AOB diversity in the prawn farm sediment and provided important foundational data for further functional studies of these microbes in mariculture environments.  相似文献   

7.
Polymerization of acrylonitrile was carried out using,for the first time,the lanthanide-sodium alkoxide clusters Ln2(OCH2CH2NMe2)12(OH)2Na8 [Ln=Yb (1),Nd (2) and Sm (3)] as single component catalysts.These heterobimetallic complexes exhibit high activity and give atactic polyacrylonitriles with high molecular weight.The polymerization temperature can be varied over the range ?78 to 50°C.The solvent has a substantial effect on the polymerization activity.The order of activity for solvents is DMF>DME≈toluene≈...  相似文献   

8.
This paper presents a novel intrusion detection model based on fuzzy cluster and immune principle. The original rival penalized competitive learning (RPCI.) algorithm is modified in order to address the problem of different variability of variables and correlation between variables, the sensitivity to initial number of clusters is also solved. Especially, we use the extended RPCL algorithm to determine the initial number of clusters in the fuzzy cluster algorithm. The genetic algorithm is used to optimize the radius deviation for the determination of characteristic function of abnormal subspace.  相似文献   

9.
XPS and AES depth composition profile studies were carried on to understand chemical components of (100) surfaces for Chengde hypersthene from Hebei Province, China, and Bamble enstatite from Norway. Also, to understand the microtopography of them the AFM observation was carried on. There are obvious differences between chemical components of (100) surface and those of mineral inner. Compared with inner mineral Si^4 proportion in total cations has no distinguished variation, whereas Ca^2 and Al^3 proportions increase respectively, and Mg^2 proportion decreases. AES depth composition prof‘de of 2000s shows that at a depth of 70 nm the atomic concentrations (%) for each element (except Si in Chengde hypersthene) slightly go up and down, but the average values have no obvious change. On the profile, the atomic concentrations (%) of Al and Si for Chengde hypersthene present a compensated relationship. Obviously, the Si and Al must have the relationship of isomorphic replacement on the (100) surface. The image of AFM shows that there is hillock growth on the (100) surface in the layered form of the polygon with 0 to several hundreds nm in thickness. The growth is a sort of secondary phyllosilicate minerals. The observation of the above-mentioned phenomenon and the recognition on the above regularities are benefit for understanding of the mechanism for weathering and water-rock reactions.  相似文献   

10.
A facile and fast approach for the synthesis of a nanostructured nickel hydroxide(Ni(OH)_2) via sonochemical technique is reported in the present study. The X-ray diffraction results confirmed that the synthesized Ni(OH)_2 was oriented in β-phase of hexagonal brucite structure. The nanostructured Ni(OH)_2 electrode exhibited the maximum specific capacitance of 1256 F/g at a current density of 200 mA/g in 1 M KOH_((aq)). Ni(OH)_2 electrodes exhibited the pseudocapacitive behavior due to the presence of redox reaction. It also exhibited long-term cyclic stability of 85% after 2000 cycles, suggesting that the nanostructured Ni(OH)_2 electrode will play a promising role for high performance supercapacitor application.  相似文献   

11.
The proton induced X-ray emission (PIXE) is used to measure the chemical ingredients of seven main elements of each sample of celadon body from Qingliangsi kiln in Baofeng County and Zhanggongxiang kiln in Ruzhou City. The PIXIE data are then analyzed by fuzzy cluster method, and the trend cluster diagram is obtained to determine their relation of classification and provenance. The result shows that the producing area of raw material of Ru porcelain bodies is concentrated in Qingliangsi kiln, while that of celadon bodies is slightly scattered in Zhanggongxiang kiln. The raw material origin of Ru porcelain bodies from Qingliangsi kiln in Baofeng County is different from that of Zhang-gongxiang kiln in Ruzhou City. The materials of Ru Guan porcelain bodies and Ru Civil porcelain bodies in Qingliangsi kiln are basically the same.  相似文献   

12.
In order to investigate the change in liquid microstructure of Al-Si alloy treated by electric pulse (EP), X-ray diffraction tests with liquid Al-Si alloy and ZL109 alloy treated or not by EP were carried out. The results show that the number of Al-Si atomic clusters decreases and that of Al-Al and Si-Si atomic clusters increases for the treated samples. The tests with ZL109 alloy indicate that a large amount of primary crystal Si appears in the solidified microstructure after treated by EP. It is found that EP canchange the microstructure of liquid metal by affecting the probability of electrons appearing in different atoms (Al and Si) in the liquid metal.The combining force of different atoms decreases relatively, and that of the same atoms increases, which is the main reason of reducing the atomic cluster with different atoms (Al-Si) and increasing the atomic cluster with the same atoms (Al-Al, Si-Si). The increasing of the atomic cluster with the same atom cluster resulted in the increasing of Si activity and the higher point of eutectics in the phase diagram. It makes a lot of primary silicon appeared in ZL109 alloy.  相似文献   

13.
1 Results In this work,five systems of polymethylmethacrylate (PMMA)-based polymer electrolytes films have been prepared by the solution casting technique.The five systems are the (PMMA-EC) system,the (PMMA PC) system,the (PMMA LiCF3SO3) system,the ([PMMA EC] LiCF3SO3) system and the ([PMMA PC] LiCF3SO3) system.The conductivity for each system is characterized using impedance spectroscopy.The conductivity of the pure PMMA,the (PMMA EC) system and the (PMMA PC) system at room temperature is 2.37×10-9,3.63×10-8 and 4.18×10-8 S·cm-1 respectively.On addition of the salt in the (PMMA LiCF3SO3) system,the conductivity is increased by two orders of magnitude.The conductivity is further increased for the plasticized-salted systems.The room temperature conductivity for the highest conducting film in the ([PMMA EC] LiCF3SO3) and ([PMMA PC] LiCF3SO3) systems is 3.54×10-5 and 2.06×10-5 S·cm-1,respectively.  相似文献   

14.
After male sterile rice plants are inoculated with secondary sporidia of Neovossia horrida in the field,the process of infection is comparatively studied in four male sterile rice lines by scanning electmnmi-croscope. The infection process of Neovossia horrida is similar in these four male sterile lines. The results show, that the hyphae of fungus penetrates directly to the stigma, and then to the ovary after inoculation for 8h. The initial teliospore is formed between the aleurone layer and seed coat after 7d and matured in 9d. Although fungus penetrates through stigma without pollination, teliospore occurs only in the healthy developing endosperma.  相似文献   

15.
NMDA receptor (NMDA-R) in the amygdala complex is critical for both long-term potentiation (LTP) and formation of conditioned fear memory. It is reported that activation of β-adrenoceptors (β-AR) in the amygdala facilitates LTP and enhances memory consolidation. The present study examined the regulatory effect of β-AR activation on NMDA-R mediated current in pyramidal cells of the basolateral nucleus of amygdala (BLA), using whole-cell recording technique. Bath application of the β-AR agonist isoproterenol enhanced NMDA-induced current, and this facilitatory effect was blocked by co-administered propranolol, a β-AR antagonist. The facilitatory effect of isoproterenol on NMDA-induced current could not be induced when the protein kinase A (PKA) inhibitor Rp-cAMPs was added in electrode internal solution.The present results suggest that β-AR activation in the BLA could modulate NMDA-R activity directly and positively, probably via PKA.  相似文献   

16.
Work hardening is a well-known phenomenon occurring in crystalline metals during deformation,which has been widely used to increase the strength of metals although their ductility is usually reduced simultaneously. Here we report that the plastic strain of Zr41Ti14Cu12.5Ni10Be22.5 (at.%) bulk metallic glasses has been increased from 0.3% for the as-cast sample to 2.5%-8.0% for samples that have experienced pre-deformation under constrained conditions. The pre-deformed glassy alloys possess more free volume and abundant introduced shear bands,which are believed to promote the activation of shear bands in post-deformation and result in an increase in plasticity. The orientation of the pre-introduced shear bands relative to the loading direction will affect the deformation behavior of pre-deformed samples. The present results show that pre-deformation of this glassy alloy will result in work toughening. This work toughening effect can be removed by isothermal annealing at a sub-Tg (glass transition) temperature,which causes annihilation of free volume and healing of shear bands.  相似文献   

17.
Clusters are shared atoms in different ways with their neighboring clusters in the crystalline phases.Cluster formula [effective cluster]1(glue atom)xcan be used to describe crystalline phases,and the effective cluster means the true cluster composition due to cluster overlapping in the phase structure.Degree of cluster sharing of Zr6Al2Ni(InMg2),Zr2Co(Al2Cu) and Zr2Cu(MoSi2) phases is investigated in this paper.Ni3Zr9,Co3Zr8 and Cu5Zr10clusters are highlighted because they have the least degree of sharing and can best represent the local atomic short-range order features of the formed phases.It is pointed out that the least sharing clusters are correlated with metallic glass formation and are verified by experiments.  相似文献   

18.
The mechanism of nucleation of hydrogen blister in metals   总被引:1,自引:0,他引:1  
The nucleating, growing and cracking of hydrogen blister have been investigated experimentally and theoretically. The results show that atomic hydrogen induces superabundant vacancies in metals. The superabundant vacancies and hydrogen aggregate into a hydrogen-vacancy cluster (microcavity). The hydrogen atoms in the microcavity become hydrogen molecules which can stabilize the cluster. And the hydrogen blister nucleates. With the entry of vacancies and hydrogen atoms, the blister nucleus grows and the pressure in the cavity increases. When the stress induced by hydrogen pressure on the blister is up to the cohesive strength, cracks will initiate from the wall of the blister.  相似文献   

19.
To examine the community structure of β-Proteobacterial ammonia-oxidizing bacteria (AOB) in prawn farm sediment, the 16S rRNA gene library was constructed with β-Proteobacterial AOB-specific primers. The library was screened by PCR-restriction fragment length polymorphism (RFLP) analysis and clones with unique RFLP patterns were sequenced. Two groups of β-Proteobacterial AOB, the Nitrosomonas and the Nitrosospira, were detected. The Nitrosomonas occupied an absolute dominant position, accounting for more than 90% of total clones in the clone library, while the Nitrosospira accounting for 5.48%. Nitrosomonas-affiliated clones were grouped into the N. marina and the N. sp. Nm143 clusters, and Nitrosospira-affiliated clones were grouped into the Nitrosospira cluster 1. No other clusters of β-Proteobacterial AOB were found. The results enriched our knowledge of AOB diversity in the prawn farm sediment and provided important foundational data for further functional studies of these microbes in mariculture environments.  相似文献   

20.
The Xiangtan manganese deposit (XTM) used to be considered a supergene oxide manganese ore in South China. We reported a new identification of the naturally outcropping cryptomelane by examining the physical, chemical and structural features of the XTM supergene oxide manganese ore. The MnO2 content was over 90%, K2O more than 3%, and water from 2.2%-3.1% which is similar to one in zeolite. The cell parameters of the cryptomelane were given as a0 = 0.9974 nm, b0 = 0.2863 nm, c0 = 0.9693 nm and β= 91.47°. There was a larger pseduotetragonal tunnel in the natural cryptomelane that was formed by [MnO6] octahedral double chains with aperture of 0.462×0.466 nm2, filled with K cations resulting in some Mn3+ substituting for Mn4+ to balance the negative charges of structure. The finding is important not only for prospecting manganese resources in South China, but also in application of octahedral molecular sieve of natural cryptomelane as that developed in the tetragonal molecular sieve of natural zeolite o  相似文献   

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