中国现代城市增长与经济增长关系分析

以中国现代历史时期城市(仅指建制城市)数量增长作为中国城市化的重要侧面,结合中国城市化动因分析,探讨了城市增长与经济发展水平的相关关系。通过对中国现代历史时期及现代化过程(实行改革开放以来)中各个阶段城市数量增长状况及增长原因分析,认为区域城市增长及城市化进程应与经济发展水平相适应。提出我国今后建制城市设置应主要基于城市化进程与经济发展水平相关关系科学规律基础上,限制城市数量的盲目增长。

Optical wireless network in home area based on white LED lights

A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.

辽金元时期辽北地区的建制及交通综述

今铁岭市辖境及法库、康平县自辽代起城邑兴起,州县林立,并一直延续到元代,从而形成了辽北区域。期间虽经金代去州存县、元代府路废置的改革,但这里的隶属沿革更加明晰,并对后世产生了深远的影响。有关这十余座州(府、路)县的地望、更迭,虽然见于史载,并经历代学者考订大体清楚,但史载者仅记其地名,考证者多拘于一城一地之论,且有疑惑、不确之说。本文拟对此综而述之,并结合多年来的实地考古调查成果,提出自己的观点及结论;同时简述了当时(以元代为主)的交通概况。