899 resultados para Piquer, Andrés, 1711-1772
Resumo:
分形几何作为定量描述自然界中复杂非线性现象的强有力工具,将其应用于南海南部断裂体系的研究中,通过
Resumo:
Photoluminescence of GaInP epilayers under hydrostatic pressure is investigated. The Gamma valley of disordered GaInP shifts sublinearly upwards with respect to the top of the valence band with increasing pressure and this sublinearity is caused by the nonlinear dependence of lattice constant on the hydrostatic pressure. The Gamma valleys of ordered GaInP epilayers rise slower than that of the disordered one. Considering the interactions between the Gamma valley and folded L and X valleys, the pressure dependence of the band gap of ordered GaInP is calculated and fitted. The results demonstrate that not only ordering along [111] directions but also sometimes simultaneous ordering along [111] and [100] directions can occur in ordered GaInP. (C) 1996 American Institute of Physics.
Resumo:
A near-infrared single-photon detection system is established by using pigtailed InGaAs/InP avalanche photodiodes. With a 50GHz digital sampling oscilloscope, the function and process of gated-mode (Geiger-mode) single-photon detection are intuitionally demonstrated for the first time. The performance of the detector as a gated-mode single-photon counter at wavelengths of 1310 and 1550nm is investigated. At the operation temperature of 203K,a quantum efficiency of 52% with a dark count probability per gate of 2. 4 * 10~(-3), and a gate pulse repetition rate of 50kHz are obtained at 1550nm. The corresponding parameters are 43% , 8. 5 * 10~(-3), and 200kHz at 238K.
Resumo:
常规的OSL(open-short-load)校准方法具有简便易行的特点,被广泛应用于单端口测量的测试夹具的校准。在本文中,OSL方法被首次扩展应用于双端口夹具的校准,并消除该方法带来的相位不确定问题。通过实验证明这种方法与SOLT(short-open-load-thru)方法同样精确。
Resumo:
为了加速日本、华北落叶松的遗传改良进程,缩短育种周期,本文建立了用于早期选择的年遗传增益最大模型 (MAGG) 和最大未来净值模型 (MFNW)。遗传力平方根比率(g)、幼-成龄遗传相关系统(r) 和遗传预测系数等参数可用8种随时间函数来逼近,根据残差平方和与非线性回归相关指数,以二次抛物线式拟合的精度最高。不同模型利用的评价标准及参数逼近的函数不同,估算的最佳选择年龄 (tmax) 也不同。对于 MFNW模型,tmax的确定受生物学因子和经济学因子的共同影响。估算的结果表明,日本、华北落叶松的早期选择都是有效的。如果轮伐期(T)为20年,考虑改良的性状为材积,对于日本落叶松可用早期的树高作为选择指标,初选在2龄进行,第二次选择在7-8龄,早期选择的相对效率 (RSE) 分别为 14.2037 和 2.5017-1.9378;对于华北落叶松,当用树高作为早期选择指标时,第一次选择在3龄 (RSE=3.1711),第二次选择在 9-10 (RSE=1.5492-1.4561),当用树高年生长最作为早期选择指标时,第一次选择在4龄 (RSE=1.1276),第二次选择在 7-8 (RSE=1.3343-1.3436)。本文对不同轮伐期的tmax和其他性状的早期选择也作了探讨。
Resumo:
为了使兰州重离子加速器冷却储存环的磁场电源控制器及时更新输出的波形数据,以TI公司的TM320C6713芯片为中央处理器,结合FPGA逻辑编程,采用双FIFO数据缓存机制和Aitken插值算法,编写并优化了磁场电源控制器软件系统。利用数据驱动模式的编程方式提高了系统的执行效率和可维护性。同时通过对更新的波形数据做Aitken插值运算,使其大小减少为原始数据的1/1024,提高了数据的传输和存储效率。经现场测试,本软件系统运行稳定可行,达到设计要求。