油松人工林年轮定年研究

对采自辽宁彰武、阜新、建平和山西方山、吉县的672个油松树芯进行精确的交叉定年和量测后,采用COFECHA程序检验定年质量,并对定年质量的影响因素进行对应分析,结果表明:各试验地点样地内树芯间的相关度为0.3807～0.7175,具有明显的地域性。山西试验地样芯的相关度明显高于辽宁,而样芯的平均敏感度则差异不明显;与主序列不一致的样本标记A与由于伪轮或缺轮导致的标记B这两种现象的发生,辽宁也多于山西;两种标记的出现与坡度、坡位、林分密度和抚育间伐等影响因素存在较为密切的关系。     

Uranium recovery from leach solution in in situ leaching of uranium with ion exchange absorption

The absorption of uranium by ion exchange resin is studied based on the characters of pregnant solution for a new uranium in situ leaching mine. The resin types, the absorption parameters and the eluting parameters are chosen in the experiments. The results showd that the 201×7 strong alkaline anion exchange resin and TSF 2 anion exchange resin had good absorption and eluting effects. The fixed bed anion exchange absorption is a suitable technology and NH4NO3＋HNO3 mixed solution is an appropriate eluting reagent for this technology.     

基于回归分析建立补充耕地数量质量实行按等级折算数学模型的研究

目前,我国在执行占用耕地补偿制度中存在以数量进行平衡,而忽视质量平衡的问题,导致占用耕地与补充耕地质量不对等,土地综合生产力下降。本文以回归分析为原理,通过对自然质量等指数、利用等指数、经济等指数及其所对应的实际标准粮产量进行回归分析,建立了数学模型,计算出不同等别间的折算系数,为云南省补充耕地数量质量按等级折算提供依据。     

网页设计与制作课程教学方法探析

随着网络资源的普及和深入,＂网页设计与制作＂这门课程已成为高职计算机应用技术专业的一门专业必修课程,针对这门课程知识复杂多样、制作易学易忘及不易熟练的特点,提出了以教学过程中任务带动兴趣为主线来分析网页制作课程的教学方法。     

基于MATLAB与VC＋＋作物产量包络线的快速生成研究

在作物产量分离中,用MATLAB与VC＋＋混合编程,可以简单而有效的解决利用上下包络线描述产量趋势的问题。以宁夏南部山区固原小麦产量为倒,讨论了在VC＋＋中调用MATLAB生成的动态链接库解决小麦产量分离的问题,并利用该拟合函数预测下一年的小麦理想、趋势产量,使用历史数据测试验证表明,该方法效果良好。     

Experimental investigation of crossflow characteristics in a multi jets system at small nozzle to plate spacing

To further extend knowledge about the detailed knowledge on the crossflow characteristic in a multi jets system under a confined space, particle image velocimetry (PIV) was employed to investigate the flow structures together with the distributions of the mean velocity components for Reynolds numbers (Re) ranging from 6 213 to 13 418, nozzle to plate spacing (H/D) varying from 0.20 to 125, respectively. Results show that the crossflow configuration is significantly different from those of large nozzle to plate spacing. In addition, a turning point H/D = 0.50 is revealed in the profile of the normalized maximum radial velocity which is associated with the heat transfer distribution on the impingement plate.     

反季节畜牧业发展刍议

分析了发展反季节畜牧业的意义,提出构建反季节草食畜牧业的主要措施是改变家畜出栏时间、暖棚育肥、实施屯草养畜及发展订单畜牧业。     

小绿叶蝉在大樱桃上的发生与防治

<正>小绿叶蝉,又称桃小绿叶蝉、桃浮尘子、桃一点斑叶蝉,为同翅目杂食性刺吸式口器害虫。近几年,在山东大樱桃产区发生日趋严重,而且发生早、密度大、为害重、时间长,已成为大樱桃的重要害虫。