摘要：In order to compare the sensitivity of short-range ensemble forecasts to different land-surface parameters in the South China region,three perturbation experiments related to the land surface model(LSM),initial soil moisture(ISM),and land–atmosphere coupling coefficient(LCC)were designed,and another control experiment driven by the Global Ensemble Forecast System(GEFS)was also *** ensemble members were initiated at 0000 UTC each day,and integrated for 24 h for a total of 40 days from the period 1 April to 10 May 2019 based on the Weather Research and Forecasting *** results showed that the perturbation experiment of the LSM(LSMPE)had the largest ensemble spread,as well as the lowest ensemble-mean root-mean-square error among the three sets of land-surface perturbed experiments,which indicated that it could represent more uncertainty and less *** ensemble spread of the perturbation experiment of the ISM(ISMPE)was generally less than that of LSMPE but greater than that of LCCPE(the perturbation experiment of the LCC).In particular,although the perturbation of the LCC could not produce greater spread,it had an effective influence on the intensity of ***,the ensemble spread of all the land-surface perturbed experiments was smaller than that of GEFSPE(the control experiment).Therefore,in future,land-surface perturbations and atmospheric perturbations should be combined in the design of ensemble forecasting systems to make the model represent more uncertainties.

摘要：介绍了一种铝合金专用水基清洗剂,论述了其清洗原理和设计配方需要考虑的关键问题。使用异辛酸钠和偏硅酸钠作为铝合金复合缓蚀剂,清洗剂不腐蚀包覆层合金。考察了清洗时间和温度与去油率的关系,得出了最佳清洗工艺条件。

摘要：为了获得最佳的分级机工艺参数,以进口产品为参考标准,采用四因素、四水平的正交实验方法设计分级实验,考察各因素对分级后钎剂的平均粒径及体积分布的影响.通过对实验的结果进行极差和方差的综合分析,结果表明:各因素对考察指标影响的大小顺序为二级频率>一级频率>风门状态>主机频率;最优组合为主机频率5Hz,一级频率10Hz,二级频率20Hz,风门状态为全开;二级频率对平均粒径及体积分布的影响显著.最后采用优化组合工艺制备了分级的钎剂,并且进行了激光粒度分析并与进口产品对比,表明所制备的分级钎剂的各项指标均与进口产品一致.