基于灵敏度序列的非线性模拟电路故障诊断

对在非线性模拟电路中采用基于灵敏度序列的故障诊断方法进行了研究.针对非线性参数特性,首先采用分段线性叠代方法构建元件的线性模型,在被测电路中采用戴维南和诺顿定理等效替换;而后分段进行测前仿真,构造故障字典.采用分段线性叠代的方法,巧妙地构建了非线性元件的分析模型,避免了求解繁复的非线性代数方程或非线性微分方程.通过对两种等效替代模型进行分析和比较,指出各自的适用范围.在分段线性化后,引入工作域分析策略,简化了含多个非线性元件电路的测前分析.理论分析和相关实验为研究非线性电路的测试与故障诊断提供了新的方法.     

射频板条CO2激光器整形光路自适应调节研究

为了解决射频板条CO2激光器因安装或腔镜热畸变造成的光路偏移问题,采用外光路偏移补偿的方法对其进行校正。研究了基于压电陶瓷的偏移补偿装置,设计了压电陶瓷驱动电路,并分析了控制精度和自适应控制方法。结果表明,通过偏移补偿装置,激光输出功率在任何占空比下均可达到或超过标准参考功率值,并通过对比有无自适应调节,激光输出功率最大相差100W,且可保持激光输出功率在2h运行中波动小于2%。此项研究可保证激光器高效运行,提高激光器的输出功率和模式的稳定性,具有较大的实用价值。     

Full Color Emission in ZnGa2O4: Simultaneous Control of the Spherical Morphology,Luminescent, and Electric Properties via Hydrothermal Approach

ZnGa₂O₄ and ZnGa₂O₄: Mn²⁺/Eu³⁺ with uniform nanosphere (diameter about 400 nm) morphology have been synthesized via a facile hydrothermal approach. XRD, Raman spectra, XPS, FT‐IR, SEM, TEM, photoluminescence (PL), and cathodoluminescecne (CL) spectra are used to characterize the resulting samples. The controlled experiments indicate the dosage of trisodium citrate and pH values are responsible for shape determination of the ZnGa₂O₄ products. The possible fast crystallization–dissolution–recrystallization formation mechanism for these nanospheres is presented. Under UV light and low‐voltage electron beam excitation, ZnGa₂O₄, ZnGa₂O₄: Mn²⁺ and ZnGa₂O₄: Eu³⁺ emit bright blue, green, and red luminescence, respectively. Based on density functional theory calculations from first principles, the green and red emission are caused by the Mn 3d and Eu 4f electronic structures, respectively. Besides, the dependence of the CL intensity on the calcination temperature and electrical conductivity of the samples is presented. The ZnGa₂O₄: Mn²⁺ nanospheres have a higher CL intensity than that of bulk samples under the same excitation condition. The realization of three primary colors from a single host material suggests that full color display based on ZnGa₂O₄ nanospheres might be achievable, showing that these materials have potential applications in lighting and display fields.     

大花无柱兰遗传多样性的SRAP标记分析

大花无柱兰是一种珍稀兰科植物,具有一定的观赏和药用价值,但数量十分稀少,该物种亟待保护。本研究采用SRAP分子标记技术,对10个居群的115份DNA样品进行PCR扩增,并开展遗传多样性分析。从81对引物中筛选出9个条带清晰、多态性好、重复性高的引物组合,共扩增得到305条谱带。在物种水平上,多态性比率（PPB）为100%,Nei’s基因多样性指数（H）为0.209 8,Shannon’s指数（I）为0.340 2;在居群水平上,PPB为24.59%～52.13%,H为0.079 6～0.165 5,I为0.120 9～0.252 3。居群水平上,基因分化度（Gst）为0.520 9,基因流（Nm）为0.459 9,遗传距离为0.091 9～0.198 4。UPGMA聚类结果表明,10个居群可分为3大类,地理距离相近的居群优先聚集。大花无柱兰的遗传多样性较为丰富,居群间存在一定的遗传分化和基因交流,可采用就地保护和人工栽培等方式加以保护。     

Theoretical analysis on the change of Marple–Hess prism''s transmittance with incident angle

In order to study the change of Marple–Hess prism's transmittance with the incident angle, all parameters related to the prism are put in a mathematical model of three coaxials system. Using Fresnel formula and multiple-beam interference theory to study the interference's effect on the transmittance in detail, we deduce a precise transmittance formula. Through the theoretical calculation, the change of transmittance with azimuth angle and plane incident angle is periodical. The frequency and amplitude of the transmittance's fluctuation will increase with increase of plane incident angle's absolute value.     

Highly Efficient Triplet-Triplet-Annihilation Upconversion Sensitized by a Thermally Activated Delayed Fluorescence Molecule in Optical Microcavities

Triplet-triplet-annihilation (TTA) upconversion sensitized by a new thermally activated delayed fluorescence (TADF) molecule, BTZ-DMAC-4Br, is investigated in whispering gallery mode (WGM) microcavities made of toluene solutions filled into quartz capillaries. Since the utilization of the excitation light is improved in WGM microcavities through total internal reflection, the upconversion efficiency is enhanced greatly and an upconversion quantum yield of 24.6% is observed, which is a dozen times higher than that measured in conventional cuvettes. To the best of knowledge, this is the highest upconversion efficiency achieved in TADF sensitized TTA systems. Not only is a new material designed, but also the results provide a novel way to improve the TTA upconversion performance by utilizing the optical cavity effect, and the TTA microcavities may be used to construct highly efficient and low-threshold photonic devices in many applications.     

Protective Effects of L-Theanine on IPEC-J2 Cells Growth Inhibition Induced by Dextran Sulfate Sodium via p53 Signaling Pathway

L-theanine is a nonprotein amino acid found in tea leaves and has been widely used as a safe food additive in beverages or foods because of its varied bioactivities. The aim of this study was to reveal the in vitro gastrointestinal protective effects of L-theanine in DSS-induced intestinal porcine enterocyte (IPEC-J2) cell models using molecular and metabolic methods. Results showed that 2.5% dextran sulfate sodium (DSS) treatment inhibited the cell proliferation of IPEC-J2 and blocked the normal operation of the cell cycle, while L-theanine pretreatment significantly preserved these trends to exert protective effects. L-theanine pre-treatment also up-regulated the EGF, CDC2, FGF2, Rb genes and down-regulated p53, p21 proliferation-related mRNA expression in DSS-treated cells, in accompany with p53 signaling pathway inhibition. Meanwhile, metabolomics analysis revealed that L-theanine and DSS treated IPEC-J2 cells have different metabolomic profiles, with significant changes in the key metabolites involved in pyrimidine metabolism and amino acid metabolism, which play an important role in nucleotide metabolism. In summary, L-theanine has a beneficial protection in DSS-induced IPEC-J2 cells via promoting proliferation and regulating metabolism disorders.     

固定化金属离子亲和发光二氧化硅纳米粒子的制备及其用于磷酸化蛋白免疫印迹标记

发展了一种能够识别磷酸化蛋白的固定化金属离子亲和发光二氧化硅纳米粒子用于免疫印迹(Western Blot)磷酸化蛋白的标记.首先通过反相微乳液St?ber方法合成了掺杂异硫氰酸荧光素硅烷化衍生物的发光二氧化硅(FITC@SiO2)球形纳米粒子,粒子平均粒径为60 nm.然后通过共聚反应在FITC@SiO2纳米粒子表面...