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51.
县级功能区划作为综合区划,既是落实省级主体功能区规划,又是编制县域空间发展规划的基础。首先探讨县级功能区划方法,然后以武定县为例运用主导因素法划分出城镇区、资源开发区、开发预留区、农业区、生态区等功能区。研究发现:(1)县级功能区划既要考虑县域资源环境本底与发展愿景,又要兼顾省级主体功能区对本县定位;(2)区划评价单元须考虑基础数据可获得性及各单项指标评价单元的统一;(3)指标体系选取以省级主体功能区划指标体系为参照,具有可行性;(4)单一区划方法无法合理区划县级各功能区单元,需多种方法相结合。 相似文献
52.
群S4对称高维自治系统的Hopf分岔 总被引:1,自引:0,他引:1
研究群对称高维自治系统的Hopf分岔.利用Lyapunov-Schmidt方法得到分岔问题的约化映射,讨论约化映射的对称性和不变子空间,由此导出分岔方程,利用分岔方程不仅研究了Hopf分岔解的对称结构,而且得到了Hopf分岔产生的条件. 相似文献
53.
谢凤艳 《浙江大学学报(理学版)》1959,46(6):656-659
设G是有限群,X是G的一个非空子集,子群H称为在G中X-ss-半置换,若H在G中有补充子群T,对于T的任意Sylowp-子群P,只要(p,|H|)=1,就存在x∈X使得HPx=PxH。通过对p2-阶子群的X-ss-半置换性研究,得到了p-幂零群的新判断。 相似文献
54.
针对苯系物泄露次生突发环境事件的应急响应问题,研究了基于案例推理和处置效果的应急方案生成方法。首先,在计算案例相似度时,为避免历史案例不全产生的情景要素遗失,基于随机森林算法,结合专家知识构建了权重求解方法,采用案例检索方法得到相似案例集;然后,构建了应急处置效果评估指标体系,以全面评价相似案例对应的处置效果;进一步,考虑多专家评价可弥补决策者知识、经验等的不足,引入了自适应群共识调整算法,得到群体评价意见,通过集结相似度与处置效果,得到了方案的综合评价值并生成最优方案;最后,用算例说明了方法的可行性和有效性。 相似文献
55.
We study the propagation of a quantum probe light in an ensemble of tripod level atoms when the atoms are coupled to two other classical control fields. First we calculate the dispersion properties, such as susceptibility and group velocity, of the probe light within such an atomic medium under the case of three-photon resonance via the dynamical algebra method of collective atomic excitations. Then we calculate the dispersion of the probe light in the case that two classical control fields have the different detunings to the relative atomic transitions. Our results show that in both cases the phenomenon of electromagnetically induced transparency can occur. Especially under the second case, we can find two transparency windows for the probe light. 相似文献
56.
57.
Branko Markoski Ana J. Šetrajčić-Tomić Dragana Rodić Igor J. Šetrajčić Svetlana Pelemiš Jovan P. Šetrajčić 《Optik》2014
The changes of optical properties under boundary presence in molecular crystal nanofilm were theoretically investigated in this work. The dispersion law and states of excitons as well as their space distribution along boundary direction have been determined using adjusted Green's function method and also by combined analytical and numerical calculations. On the basis of real and imaginary part of relative permittivity, both absorption and refraction indices were determined, and the influences of boundary parameters on occurrence of a very selective and strictly discrete absorption were analyzed. 相似文献
58.
We propose multisymplectic implicit and explicit Fourier pseudospectral methods for the Klein-Gordon-Schrödinger equations. We prove that the implicit method satisfies the charge conservation law exactly. Both methods provide accurate solutions in long-time computations and simulate the soliton collision well. Numerical results show the abilities of the two methods in preserving charge, energy, and momentum conservation laws. 相似文献
59.
Hawking radiation as tunnelling from arbitrarily dimensional Reissner-Nordstrom de Sitter black hole 下载免费PDF全文
This paper extends Parikh-Wilzcek's recent work, which treats the Hawking radiation as a semi-classical tunnelling process from the event horizon of four dimensional Schwarzshild and Reissner-Nordstrom black holes, to that of arbitrarily dimensional Reissner-Nordstrom de Sitter black hole. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the factually radiant spectrum is no longer precisely thermal after taking the dynamical black hole background and energy conservation into account, but is consistent with the underlying unitary theory and then satisfies the first law of the black hole thermodynamics. Meanwhile, in Parikh-Wilzcek's framework, this paper points out that the information conservation is only suitable for the reversible process but in highly unstable evaporating black hole (irreversible process) the information loss is possible. 相似文献
60.
First-principles investigation of chemical modification on two-dimensional iron–phthalocyanine sheet 下载免费PDF全文
Successful synthesis of single iron–phthalocyanie(FePc) framework layer on substrate and its transferrable properties open the door for decorating the separately distributed transition metals for exploring the diverse properties. We have studied the effects of chemical modification on two-dimensional FePc organometallic framework with density functional theory. For simplicity, the non-metal atoms with variant valence electrons are used as prototypes to estimate the effects from chemical modifications with different functional groups. The thermo-stabilities of the non-metal atom decorated complex sheet materials have been estimated by the first-principles constant energy molecular dynamic simulations. Upon the nonmetal atom adsorption, the magnetic moment could be changed from 2 μBto 0, 1, 2, and 3 μBper unit cell for the case of tetra-, penta-, hexa-, and hepta-valent non-metal modifications, respectively, showing interesting promise to tailor its magnetic properties for potential applications. 相似文献