基于动态规划的水电站机组间负荷分配程序开发

水电站机组间负荷分配计算中的阶段变量与状态变量的个数越多,计算量就越大,且计算程序也越复杂,因而仅用手工计算很难做到。为此,利用动态规划法建立了水电站厂内经济运行流量分配数学模型。使用编程软件Visual Basic开发了水电站机组间负荷分配程序;该程序界面友好,使用方便,且能大大提高计算速度。应用该程序,对水电站机组间的负荷分配进行了实际应用计算,得出了经济效益最优的负荷分配方案。     

诊断X射线能谱影响因素的模拟与分析

诊断X射线的能谱分布受到一系列因素的影响。为了进一步了解影响诊断X射线能谱的因素,从而为评估光机自身特性导致诊断结果的差异提供技术基础,通过仿真模拟的方法建立了诊断X射线光机的物理模型。模拟计算和比较了诊断X射线光机在不同管电压、发射角、过滤材料、纹波等条件下的出射能谱。研究结果表明,管电压、发射角、过滤材料(包括厚度)以及管电压纹波都会影响射线能谱分布和平均能量。诊断X射线光机的上述关键参数可能会直接影响诊断结果的可靠性,在光机运行过程中,参数的选择和质量控制方面需要予以重视。     

创新教育:工程创新之引擎

创新包括科学创新、技术创新和工程创新。工程创新是创新活动的主战场,它使"科技是第一生产力"得以实现。而创新教育对培养具有创新精神和创新能力的工程创新人才意义重大。实施创新教育的根本途径是营造创新文化、树立科学精神、更新教育观念。     

g因子的蒙特卡罗模拟计算

在电离辐射空气比释动能基准量值复现过程中, g因子作为关键组成部分之一,参与量值复现和不确定度计算,其量值的确定需要通过光子的质能传输系数和质能吸收系数计算得到。采用不同的软件,在不同参数设置条件下模拟计算并对结果进行比较。结果显示采用EGSnrc计算结果更为合理,而且对于低能光子来说,尽管g因子相对较小,但在不同的参数设置条件下所得到的数值差异较大。因此在涉及到低能光子的质能传输系数和质能吸收系数的计算和使用过程中,需对有关的相互作用的物理机制予以重视。     

16万 t／a尿素装置节能技术改造

从高压合成系统、中压系统、蒸发系统、DCS系统、主要动力设备等5个方面分析了16万t/a尿素装置节能技术改造的原因,介绍了尿素装置的主要节能技术改造措施。结果表明：改造后的生产运行情况与原设计及国内相同规模的企业相比,吨尿素的氨耗降低了13 kg,电耗降低了34 kW,优级品率上升,各项指标达到了预期目标。     

Ray Tracing Simulation of Images of Dislocations and Inclusions on X-Ray Topographs of GaAs Epitaxial Wafers

In x-ray topography studies, ray tracing simulation has been particularly useful in identifying and characterizing Burgers vectors of dislocations using only one reflection instead of the traditional method of recording at least three reflections and applying $$\vec{g} \cdot \vec{b} = 0$$ and $$\vec{g} \cdot \vec{b} \times \vec{l} = 0$$ criteria. In this study, ray tracing simulation of expected dislocations in (AlxGa(1–x))0.5In0.5P epitaxial layers on GaAs substrates has been carried out by using well-known expressions for displacement fields around dislocations. By comparing the simulated images with observed images on monochromatic x-ray topographs, the Burgers vectors have been characterized. The x-ray topographs from the (AlxGa(1–x))0.5In0.5P epitaxial layers also reveal a unique pattern consisting of a series of circular dark contrast features from inclusions. These dark circles decrease in size as the center of the inclusions is approached. Ray tracing simulated image of an inclusion assuming a spherical strain field matches well with the experimental image, thus providing information on the level of strain around the inclusion.     

基于小波分析算法的水轮机组振动故障诊断

故障诊断技术是水轮机组安全稳定运行的关键技术之一,也是水轮机组提高运行效率、进行预知维修及科学管理的重要基础.在小波分析算法和科学计算软件MATLAB的基础上,利用多分辨率分析(MRA)技术先对已经采集好的水轮机主轴振动信号的突变部分段做db3分解,确定信号突变点位置,再计算Lipschitz指数,评估故障程度.结果表...     

Cooperative energy acceptor of three Yb3+ ions

Our previous work first reported the cooperative sensitized luminescence from Cu~(2+) or Pb~(2+) by three clustered Yb~(3+) ions, in which three NIR photons can be converted into a high energy photon. Could a reverse process happen that a high energy photon is cut into three NIR photons? This work demonstrated an example of three-photon quantum cutting(QC) phosphor,CaF_2:Ce~(3+),Yb~(3+), in which three clustered Yb~(3+) ions(Yb~(3+)-trimer) cooperatively and indirectly received a 306 nm ultraviolet(UV) photon energy transferred from a Ce~(3+) ion in 5 d excited state and emitted three 975 nm near-infrared(NIR)photons. The cluster destruction experiments were designed to verify the necessity of the presence of Yb~(3+)-trimers for QC. The dynamical analysis on luminescence of Ce~(3+) ions confirmed the energy transfer from Ce~(3+) ions to Yb~(3+)-trimers. The doping concentration effect on luminescence was investigated.Furthermore, the maximum energy transfer(ET) efficiency and the corresponding QC efficiency were estimated to be 61% and 222%, respectively. Therefore, the reported three-photon QC phosphor has an attractive prospect in efficiently harvesting solar energy for silicon solar cells.     

Synthesis,characterization and acidochromism of Poly (2-<Emphasis Type="Italic">N,N</Emphasis>–dimethylamino-4,6-Bis (2-thienyl)-pyrimidine)

A new monomer (2-N,N-dimethylamino-4,6-Bis (2-thienyl)–pyrimidine) was synthesized and its homopolymer was successfully prepared by using Ferric trichloride (FeCl₃) as an oxidant. The structure of the polymer and monomer was fully characterized by ¹H–NMR, FTIR, UV-vis, Fluorescent spectroscopy and X-ray diffraction pattern. The polymer gives rise to a band at λ _max = 391 nm. The polymer showed the PL spectrum, gave a peak at 507 nm.We have observed that the polymer was sensitive to inorganic acids and the acidochromism behavior was investigated applying organic acid such as CF₃COOH. The corresponding UV-Vis peaks were observed at 464 nm and 357 nm respectively. X-ray diffraction data shows that polymer has a certain crystallinity. The polymer exhibited an [η] value of 0.26 dLg⁻¹ at 25 °C in H₂SO₄ (w = 98%).     

半导程螺旋泵转子加工工艺分析及夹具

半导程螺旋泵的核心部分是转子 ,转子的特殊性在于它是由左右各半个对称螺旋组成的整体 ,是该泵最重要的零件 ,也是最难加工的零件 ,本文在分析转子加工工艺的基础上 ,创新设计了一套加工转子螺旋面的夹具 ,该夹具结构简单 ,既可提高转子加工精度 ,又经济使用方便 ,适用于转子批量生产。