After thermodynamic calculation on several operation conditions of the furnace , cold - state flow and resistance mensuration , the combustion of the tubular - furnace hearth was changed into swirl and addition of radiate cylinder and oxygen content detection minish 1 . 25 surplus air to less than 1 . 15 , improving the combustion condition and convection and radiate heat transfer efficacy , resuling in reducing the waste - gas temperature 45 , decreasing exhaust gas loss , and saving fuel by 6 % 摘要通过对加热炉几种工况进行热力计算、冷态试验的流场分布及阻力测定和热态试验的炉膛温度场分布及管壁温度等参数的测定，确定将管式加热炉炉膛内直流燃烧改为旋流场燃烧和增加辐射筒，增设烟气含氧量分析，可以将燃烧的过剩空气系数从1 . 35减小到1 . 15以下，极好地改善炉膛内的燃烧状况和对流辐射传热效果，从而降低排烟温度45 ，减少加热炉排烟损失，节约了煤气量6 %以上。
The tuning curve of type - i phase matching of bbo opo are measured with accuracy ; the maximum conversation in total of the system is about 31 % at 615 . 6 nm , and it is fitted well with the gtp formula ; in the end we compared the output linewidth and unstable cavity far field beam qua lity of the bbo opo under the condition of type - i phase matching and type - ii phase matching , it is proved that we can obtain the parametric output of linewidth less than 0 . 3 nm and the beam divergence angle approaching diffraction limits by take the advantages of type - ii phase matching and unstable cavity designs 测量了该系统的转换效率最大为31 ，并能与理论公式极好地吻合，最后比较了在类相位匹配条件下和类相位匹配条件下的bbo - opo的输出线宽，以及非稳腔的远场光束质量，实验结果表明，利用类相位匹配以及非摘要稳腔设计可以获得线宽小于0 3nlm 、光束发散角接近衍射极限的参量光输出。
