振兴东北老工业基地的体制思考

由厦门大学财政系提供的2003年国有资产监管体制与公共财政制度改革国际会议论文集15党的十六大报告中已明确提出：“支持东北地区等老工业基地加快调整和改造，支持以资源开采为主的城市和地区发展接续产业……” 这是我国中央政府首次提出振兴东北老工业基地的方略。加快东北老工业基地的调整、改造和振兴，对我国经济的发展有着重要而深远的意义：有利于促进地区经济的协调发展，有利于增强国民经济的活力和发展后劲，有利于提高我国产业和企业的国际竞争力。值得一提的是,由于东北老工业基地的国有经济比重偏高、市场发育不足的事实赋予了这次振兴东北老工业基地更为深远的意义，有利于推动我国国有经济的布局和结构，进一步推动我国国有资产管理体制的改革

An experimental investigation of supersonic combustion of cracked JP-10

In this paper, a novel two-stage hydrocarbon fuel heating and delivery system was used to more accurately simulate the state of fuel in the cooling channel of the regenerative cooling engine. Different cracking degrees (9-23%) experiments of JP-10 were conducted by using the new heating system, and cracked products were sampled and analyzed. The ignition delay time of high cracking degree product is shorter than that of low cracking degree product. The laminar flame speed of JP-10 and low cracking degree products are similar, the laminar flame speed of high cracking degree products is 32% faster than that of JP-10 when the equivalence ratio is 1.0, and the laminar flame speed of surrogate gas fuel is two times faster than that of JP-10. The supersonic combustion experiments of JP-10 with different cracking degrees and equivalence ratios were also employed at Mach number 3.0 of the isolator entrance, with total temperature-1550 K, total pressure-1.5 MPa, as well as at Mach number 2.5 of the isolator entrance, with total temperature-1250 K, total pressure-0.78 MPa, respectively. The static pressure along the axis of combustor was measured, while the velocity and temperature of the airflow at the exit of combustor were also measured by the tunable diode laser absorption spectroscopy (TDLAS). The distributions of airflow velocity, total temperature and static temperature along the combustor with different conditions were analyzed through a one-dimensional analysis method. The deviations of velocity and temperature of the airflow are less than-4% and-5% for Mach number 3.0, and less than 9% and 4% for Mach number 2.5, which indicates the calculations are in accordance with the TDLAS detections to some extent at Mach 3.0. Specially, supersonic combustion of JP-10 with different cracking degree at the same fuel tem-perature and equivalence ratio were obtained, which benefits studying the influence of different cracking degrees fuel on supersonic combustion characteristics. Furthermore, the experimental data will be helpful for validating the simulation of supersonic combustion

城市不同下垫面的能量平衡及温度差异模拟

城市能量平衡是研究城市热岛效应的物理基础。利用北京市教学植物园2010年的实测数据,设置不同类型下垫面(植被覆盖类型:林地、草地和不透水层覆盖类型:道路、房屋),利用局地尺度城市气象参数化方案模拟并分析了相同气象条件和净辐射通量输入下,不同类型下垫面的显热、潜热通量及蒸散降温效应的差异。结果显示:(1)不同类型下垫面的各能量支出项有明显差异,植被覆盖区域和不透水层覆盖区域的波文比年均值分别为0.28和4.60,且在植被生长季差异较大;(2)城市扩展过程中道路、房屋替换林地、草地的过程,也是显热增加而潜热减少的过程。植被层向不透水层转换的过程中,显热通量年均增加32.74W/m2,潜热通量减少38.87W/m2,储热通量增加7.95W/m2;(3)理论上,植被蒸散的年降温效应使单位面积植被覆盖区域的气温比不透水层区域可低2.63℃