东南部欠发达地区县域城乡空间统筹发展的规划思考

随着国内区域经济联动的加强,产业布局的调整升级,以及大区域交通条件的改善,我国城市化经济已经进入了一个＂全球化-区域化＂的新发展时期.东南部欠发达地区的城市化、工业化发展面临着若干重大机遇.通过分析县域城乡空间发展存在的一般性问题和制约因素,提出：东南部欠发达地区的发展应以空间规划作为切入点,通过空间规划与行动集成,将城乡统筹概念落实到县域空间层面上,构建一个综合的发展战略与行动规划.     

Synthesis and structural investigation of two metal-organic frameworks constructed from alkaline earth metal cations and organic ligand 5-nitroisophthalic acid (5-NO<Subscript>2</Subscript>-H<Subscript>2</Subscript>BDC)

Two supermolecular co-ordination polymers [M(5-NO₂-BDC)(H₂O)₆] [M = Sr(1), Ba(2)] were prepared by the assembly of alkaline earth metal cations and symmetric organic ligand 5-NO₂-H₂BDC, respectively. These two complexes have been characterized with the aid of elemental analysis, thermal analysis, infrared spectroscopic and X-ray crystallography. Both 1 and 2 have a similar 3D flowerlike supramolecular assembled by multiple interpenetration of the 1D chains where 12-membered rings share common C–O–M edges with each other extended by O–H···O hydrogen bonds. The co-ordination geometry around M (II) ions could be described as distorted tricapped trigonal prism arrangements.     

Reverse supply chain coordination by revenue sharing contract: A case for the personal computers industry

Products that are not recycled at the end of their life increasingly damage the environment. In a collection – remanufacturing scheme, these end-of-life products can generate new profits. Designed on the personal computers industry, this study defines an analytical model used to explore the implications of recycling on the reverse supply chain from an efficiency perspective for all participants in the process. The cases considered for analysis are the two- and three-echelon supply chains, where we first look at the decentralized reverse setting followed by the coordinated setting through implementation of revenue sharing contract. We define customer willingness to return obsolete units as a function of the discount offered by the retailer in exchange for recycling devices with a remanufacturing value. The results show that performance measures and total supply chain profits improve through coordination with revenue sharing contracts on both two- and three-echelon reverse supply chains.     

Liquid Membrane Transport Behavior of Functional Substituted Crown Ethers for Amino Acids

Crown compounds offer a variety of interesting functions based on their specific bindings of organic guest species1,2. In particular, they can act as carriers in ion- extraction, membrane transport, and phase-transfer reactions. In contrast to the large variety of synthetic ionophores for cation transport, there are only a few examples of synthetic anion transport ionophores. Therefore, it appears highly desirable to search for a new class of ionophores with excellent transport abilities fo…     

Studies on the Synthesis and Complexing Behavior of Crown Ethers with External Coordination Center

Ligands capable of positioning two or more very different metal cations, like transition metal and alkali or alkaline earth metal cations, have been described recently1-3. Reinhoudt et al. have synthesized a number of ligands with the cavity for transition metal cations as well as the cavity for alkali metal cations and the corresponding comlexes with different kinds of metal ions4,5. It was anticipated that co-complexation of a hard cation closing to the complexed transition metal cation woul…     

XANES and EXAFS study of some metal-metalloid glasses

XANES and EXAFS techniques are proving very popular in the study of local environment in disordered systems. Results of such studies in a large number of metal (Fe, Co, Ni, etc)-metalloid (B, Si, C, etc) glasses are reported. Experiments were done with synchrotron radiation as well as an x-ray tube. The values of bond lengths and co-ordination numbers computed from one-electron single scattering Fourier transform method turn out substantially smaller. The values of bondlength determined from the other EXAFS calculation method and the multiple-scattering computation scheme show good agreement. Importance of choice of suitable reference materials for analysis of data is emphasized. The experimental work was done at EXAFS 5.1 Station at Daresbury Laboratory, U.K.