共查询到20条相似文献,搜索用时 31 毫秒
1.
Yousong Gu Yongping Zhang Xiangrong Chang Zhongzhuo Tian Nanxian Chen Dongxia Shi Xiufang Zhang Lei Yuan 《中国科学A辑(英文版)》2000,43(2):185-198
C3N4 films have been synthesized on both Si and Ft substrates by microwave plasma chemical vapor deposition (MPCVD) method. X-ray
spectra were calculated for single phase α-C3N4 and β-C3N4 respectively. The experimental X-ray spectra of films deposited on both Si and Pt substrates showed all the strong peaks
of α-C3N4 and β-C3N4 so the films are mixtures of α-C3N4 and β-C3N4. The N/C atomic ratio is in the range of 1.0–2.0. X-ray photoelectron spectroscopy (XPS) analysis indicated that the binding
energy of Is and N ls are 286.2 eV and 399.5 eV respectively, corresponding to polarized C-N bond. Fourier transform infrared
absorption (FT-IR) and Raman spectra support the existence of C-N covalent bond in the films. Nano-indentation hardness tests
showed that the bulk modulus of a film deposited on Pt is up to 349 GPa 相似文献
2.
A successful experimental synthesis of pure crystalline β- and α-C3N4 films on Si(100) substrate was carried out by bias-assisted hot filament chemical vapor deposition (bias-HFCVD). It is found
that a mixed-phase C3-I-SixNy buffer layer was formed between the Si substrate and the C-N film. A “lattice match selection” was proposed to study the
growth mechanism of C3N4 clusters composed of many crystal columns with hexagonal facets.
Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences. 相似文献
3.
Large size C70 single crystals with the dimension of more than 5 mm are grown from the vapor phase by controlling nucleation. X-ray diffraction
and electron diffraction confirm that in the C70 single crystal a phase of the hexagonal close-packed (hcp) structure coexists with a minor face-center-cubic (fcc) phase
at room temperature. The morphologies and their formation mechanism of the C70 single crystals are investigated by means of scanning electron micrascopy and optical microscopy. The influence of growth
conditions on the morphologies of C70 single crystals is discussed.
Project supported by the National Natural Science Foundation of China (Grant No. 59772026). 相似文献
4.
Hongnian Li Yabo Xu Shining Bao Haiyang Li Peimo He Haijie Qian Fengqin Liu Yibulaxi Kuirexi 《中国科学A辑(英文版)》2000,43(11):1189-1194
K3C60, single crystal film was prepared on the cleaved (111) surface of C60, single crystal. Synchrotron radiation angle-resolved photoemission spectra were measured at normal emission with sample
temperature at × 150K. Up to four subpeaks of LUMO-derived band were observed. These sub-peaks exhibit distinct energy dispersions
which resemble in general the theoretical ones calculated for K3C60 at low temperature with the so-called one-dimensional disordered structure. But there is large deviation of experimental
sub-band intervals from the theoretical values. This result is meaningful for the studies of the physical properties of alkali-doped
C60 solids, e.g. the mechanism for superconductivity. 相似文献
5.
We study the concepts of the 𝒫C-projective and the ?C-injective dimensions of a module in the noncommutative case, weakening the condition of C being semidualizing. We give the relations between these dimensions and the C-relative Gorenstein dimensions (GC-projective and GC-injective dimensions) of the module. Finally, we compare, in some circumstances, the global 𝒫C-projective dimension of a ring and the global dimension of the endomorphisms ring of C. 相似文献
6.
A Variation of an Extremal Theorem Due to Woodall 总被引:1,自引:0,他引:1
We consider a variation of an extremal theorem due to Woodall [12, or 1, Chapter 3] as follows: Determine the smallest even integer (3C1,n), such that every n-term graphic sequence = (d1, d2,..., dn) with term sum () = d1 + d2 + ... + dn (3C1,n) has a realization G containing a cycle of length r for each r = 3,4,...,l. In this paper, the values of (3Cl,n) are determined for l = 2m – 1,n 3m – 4 and for l = 2m,n 5m – 7, where m 4.AMS Mathematics subject classification (1991) 05C35Project supported by the National Natural Science Foundation of China (Grant No. 19971086) and the Doctoral Program Foundation of National Education Department of China 相似文献
7.
Xiangyi Zhang Jingwu Zhang Fuxiang Zhang Wen Yu Duanwei He Liming Cao Jianhua Zhao Riping Liu Yingfan Xu Wenkui Wang 《中国科学A辑(英文版)》1999,42(4):407-413
The formation of nanocrystalline Fe73.5 Cu1Nb3Si13.5 B9 alloy by annealing an amorphous Fe73.5Cu1Nb3Si13.5B9 alloy at a temperature of 823 K under pressures in the range of 1–5 GPa is investigated by using X-ray diffraction, electron
diffraction, and transmission electron microscopy. The high pressure experiments are carried out in belt-type pressure apparatus.
Experimental results show that the initial crystalline phase in these annealed alloys is a-Fe solid solution (named a-Fe phase
below), and high pressure has a great influence on the crystallization process of the a-Fe phase. The grain size of the a-Fe
phase decreases with the increase of pressure (P). The volume fraction of the a-Fe phase increases with increasing the pressure
as the pressure is below 2 GPa, and then decreases (Pδ2 GPa). The mechanism for the effects of the high pressure on the crystallization
process of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy is discussed
Project supported by the National Natural Science Foundation of China (Grant No. 19674070) and the Natural Science Foundation
of Hebei Province. 相似文献
8.
Satoshi Yoshiara 《Journal of Algebraic Combinatorics》1996,5(3):251-284
It is shown that a flag-transitive C
3-geometry of finite order (x, y) with x2 is either a finite building of type C
3 (and hence the classical polar space for a 6-dimensional symplectic space, a 6-dimensional orthogonal space of plus type, a 6- or 7-dimensional hermitian space, a 7-dimensional orthogonal space, or an 8-dimensional orthogonal space of minus type) or the sporadic A
7-geometry with 7 points. 相似文献
9.
Jialin Zhu Liangchen Chen Richeng Yu Fengying Li Jing Liu Changqing Jin 《中国科学A辑(英文版)》2002,45(7):900-905
In situ high pressure energy dispersive X-ray diffraction measurements on the layered perovskite-like manganate Ca3Mn2O7 powder under pressures were performed by using the diamond anvil cell with synchrotron radiation. The results show that the
structure of layered perovskite-like manganate Ca3Mn2O7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0–35 GPa. One was at about 1.3 GPa with the crystal structure
changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic
back to another tetragonal. 相似文献
10.
Diamond nucleation on the surface of C60 thin layers and intermediate layer of Si substrates are studied by scanning electron microscopy (SEM). The cross-section
SEM images of diamond films show that diamond grains really nucleate on the surface of C60 thin layers. The SEM images of diamond nucleating sites show the nucleating aggregation of diamond on C60 surfaces. The preferential oriented diamond films are observed. The plasma pretreatment of C60 sublimating layers is a key factor for diamond nucleation. 相似文献
11.
Single C3N4 crystals with 1–3 μ in length and 300 nm in cross area was obtained on nickel substrate. The results rule out the uncertainty of the experimental lattice parameters caused by C-Si-N phase when the growth was on silicon. The X-ray diffraction and transmission electron microscopy with selective-area electron diffraction give the lattice constantsa = 0.624 nm andc = 0.236 nm for β-C3N4, and α=0. 638 nm andc = 0.464 8 nm for α-C3N4, which are respectively 2.5% and 1.3% lower than those of the latest first-principle calculations. An N:C ratio of 1.30–1.40 was determined by energy dispersive X-ray. Based on the experimental lattice constants, the bulk modulus of the obtained β-C3N4 are in the region of 425–445 GPa. 相似文献
12.
13.
In this paper, we present a new one-step smoothing Newton method proposed for solving the non-linear complementarity problem with P0-function based on a new smoothing NCP-function. We adopt a variant merit function. Our algorithm needs only to solve one linear system of equations and perform one line search per iteration. It shows that any accumulation point of the iteration sequence generated by our algorithm is a solution of P0-NCP. Furthermore, under the assumption that the solution set is non-empty and bounded, we can guarantee at least one accumulation point of the generated sequence. Numerical experiments show the feasibility and efficiency of the algorithm. 相似文献
14.
A C2.L-geometry is a geometry of rank 3 with elements called points, lines and quads, where residues of points are linear spaces, residues of lines are generalized digons and residues of quads are generalized quadrangles. Some sufficient conditions can be found in the literature for a C2.L-geometry to be a quotient of a truncated Cn-building. We shall weaken those conditions in this paper. 相似文献
15.
Huisheng Wang Kun Ma Yanwei Liu Zhiqiang Peng Dafu Cui Huibin Lu Yueliang Zhou Zhenghao Chen Lin Li Guozhen Yang 《中国科学A辑(英文版)》1997,40(5):522-527
By using laser molecular beam epitaxy (L-MBE), atomic scale epitaxid growth of BaTiO3(BTO) thin films on SrTiO3 (STO) substrates is achieved. Measurements of reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD),
scanning electron microscopy, and transmission electron microscopy reveal that the BTO films arec-axis oriented single crystals with smooth surface. The multi-layer ferroelectric/superconducting heterostructures are also
prepared and the ferroelectric properties of BTO films are studied. The results show that by using L-MBE technique, high quality
BTO films and improved device performance can be obtained.
Project supported by the National Natural Science Foundation of China, the National Department of Finance, and the National
Center for R and D on Superconductivity of China. 相似文献
16.
It is shown in [4] that if a normal matrix,A satisfies some conditions then |C,1|
k
summability implies |A|
k
summability wherek≥1. In the present paper, we consider the converse implication. 相似文献
17.
在(CPS)_C及(PS)_C条件下,利用Ambrosetti-Rabinowitz对称形式的山路引理,研究了一类二阶哈密尔顿保守系统在给定能量面上的无穷多个周期解的存在性问题. 相似文献
18.
Jerzy Ka?kol Stephen A. Saxon Aaron R. Todd 《Journal of Mathematical Analysis and Applications》2004,297(2):495-505
Buchwalter and Schmets reconciled Cc(X) and Cp(X) spaces with most of the weak barrelledness conditions of 1973, but could not determine if -barrelled ⇔ ?∞-barrelled for Cc(X). The areas grew apart. Full reconciliation with the fourteen conditions adopted by Saxon and Sánchez Ruiz needs their 1997 characterization of Ruess' property (L), which allows us to reduce the Cc(X) problem to its 1973 status and solve it by carefully translating the topology of Kunen (1980) and van Mill (1982) to find the example that eluded Buchwalter and Schmets. The more tractable Cp(X) readily partitions the conditions into just two equivalence classes, the same as for metrizable locally convex spaces, instead of the five required for Cc(X) spaces. Our paper elicits others, soon to appear, that analytically characterize when the Tychonov space X is pseudocompact, or Warner bounded, or when Cc(X) is a df-space (Jarchow's 1981 question). 相似文献
19.
The N-Isometric Isomorphisms in Linear N-Normed C^*-Algebras 总被引:3,自引:3,他引:0
Chun-Gil PARK Themistocles M. RASSIAS 《数学学报(英文版)》2006,22(6):1863-1890
We prove the Hyers-Ulam stability of linear N-isometries in linear N-normed Banach mod- ules over a unital C^*-algebra. The main purpose of this paper is to investigate N-isometric C^*-algebra isomorphisms between linear N-normed C^*-algebras, N-isometric Poisson C^*-algebra isomorphisms between linear N-normed Poisson C^*-algebras, N-isometric Lie C^*-algebra isomorphisms between linear N-normed Lie C^*-algebras, N-isometric Poisson JC^*-algebra isomorphisms between linear N-normed Poisson JC^*-algebras, and N-isometric Lie JC^*-algebra isomorphisms between linear N-normed Lie JC^*-algebras.
Moreover, we prove the Hyers- Ulam stability of t:heir N-isometric homomorphisms. 相似文献
20.
Bidisha Borkakaty Kanwar Sen Manju Agarwal 《Mathematical and Computer Modelling》2009,50(7-8):1067-1082
In this paper, we find the busy period density of queues in explicit computational form, through lattice path (LP) approach. Both the arrival and service time distributions are approximated by 2-phase Cox distribution C2, which has a Markovian property enabling us to use LP combinatorics. Since any distribution with rational Laplace–Stieltjes transform (LST) and square coefficient of variation (CV2) lying in [1/2,∞) can be approximated by a C2([M. Agarwal, K. Sen, B. Borkakaty, Busy period density of queueing system C3/M/1, Journal of Combinatorics, Information and Systems Sciences 31 (1–4) (2006) 127–161]), the results obtained would be applicable to a very wide class of distributions occurring in real life. 相似文献