马铃薯原原种收获分级设备研究

随着我国马铃薯产业的高速发展,对马铃薯原原种的种植和收获设备研究发展较快.目前,我国马铃薯收获主要以人工挖掘和机械收获为主.为降低劳动强度,收获分级设备已取得重大突破.随着马铃薯收获设备的使用,收获效率得到明显提升.文章针对马铃薯原原种收获分级设备进行研究,以期降低收获成本.     

Thermoluminescence characteristics of NaSr4（BO3）3：Ce^3＋ under β-ray irradiation

The thermoluminescence (TL) properties of Ce3+ doped NaSr4(BO3)3 phosphor under the β-ray irradiation were reported. The polycrystalline sample was synthesized by high temperature solid-state reaction. The TL glow curve of NaSr4(BO3)3:Ce3+ phosphor was com-posed of only one peak. TL kinetic parameters of NaSr4(BO3)3:Ce3+ were deduced by the peak shape method, the activation energy (E) was 0.590 eV and the frequency factor was 1.008×106s-1. TL dose response was linear in the range of measurement. The 3-dimensional (3D) TL emission spectrum was also recorded, the emission spectrum consisted of two bands located at 441 and 479 nm respectively, corresponding to the characteristic 4f05d1→2F(5/2,7/2) transitions of the Ce3+ ion. The fading behavior of the NaSr4(BO3)3:Ce3+ phosphor over a period of 15 d was also studied.     

Long-lasting phosphorescence study on Y_3Al_5O_（12） doped with different concentrations of Ce~（3＋）

Long-lasting phosphorescence (LLP) was observed in Ce-doped Y3Al5O12 phosphors synthesized in reducing atmosphere. The characteristic emission of the 2D-2F5/2 and 2D-2F7/2 transition of Ce3+ in photoluminescence (PL) and LLP spectra was studied. It was interesting that the ratio between the peak areas of 2D-2F5/2 and 2D-2F 7/2 transitions in the PL spectrum was different from the ratio of that in LLP emission spectrum. And the ratios had different change regularities with increased Ce3+ concentration. The p...     

利用白光扫描干涉测量表面微观形貌

由于激光显微干涉只能测量表面微观形貌的相对高度值,不能进行绝对测量,本文提出了白光显微干涉测量方法,研制了测量仪器,并对CCD像素格值和PZT进行了标定.该仪器以白光干涉理论为基础,利用空间频域算法计算白光干涉图零级条纹中心位置,根据零级条纹中心移动量来得到被测工件表面微观形貌.对被测工件表面进行了测试,试验结果表明:...     

一种标定Soleil-Babinet补偿器的新方法

提出了一种高精度标定索累-巴比涅(Soleil-Babinet)补偿器的新方法.在光谱扫描法测量系统中,将多级半波片置于被测补偿器后,以半波片的延迟量为基准,高精度地标定出补偿器的延迟量所对应的测微丝杆位移.该方法利用光强透过率和波长的关系得到延迟量,避免了光强值直接测量法误差源多、精度不高的缺点;同时解决了光谱扫描法不易测量零级相位器件的问题.实验中以工作波长为633 nm的多级半波片为基准,对Soleil-Babinet补偿器进行标定.分析表明,该方法在确定延迟量为0和λ的位置时,精度可达0.45 nm;0～λ范围之间的延迟量最大测量误差仅为3.2 nm.     

淀粉基脂肪替代物原料研究进展北大核心

碳水化合物基脂肪替代物是一种公认安全脂肪替代物,受到人们越来越多关注。淀粉基脂肪替代物是碳水化合物基脂肪替代物一种;该文从原料方面介绍淀粉基脂肪替代物研究状况及制备淀粉基脂肪替代物的原料最新进展。