基于半导体光放大器的一阶IIR微波光子学滤波器及其品质因素分析

对基于半导体光放大器(SOA)环形腔结构的一阶无限冲击响应(IIR)微波光子学滤波器的品质因数(Q值)进行了实验和理论研究. 通过在有源环内置入窄带光滤波器,并调节有源环的输入光功率、SOA抽运电流、实验得到的最高Q值接近200. 理论分析表明为了得到较高的Q值,应尽可能提高信噪比和信号光的环路增益. 在考虑了 SOA中放大的自发辐射(ASE)噪声的基础上,计算了输入光功率、SOA抽运电流、环内光滤波器的带宽对Q值的影响. 数值计算的结果与实验现象基 关键词： 微波光子学滤波器 Q值')" href="#">Q值 半导体光放大器 放大的自发辐射     

Sequence‐related amplified polymorphism,an effective molecular approach for studying genetic variation in Fasciola spp. of human and animal health significance

In the present study, a recently described molecular approach, namely sequence‐related amplified polymorphism (SRAP), which preferentially amplifies ORFs, was evaluated for the studies of genetic variation among Fasciola hepatica, Fasciola gigantica and the “intermediate” Fasciola from different host species and geographical locations in mainland China. Five SRAP primer combinations were used to amplify 120 Fasciola samples after ten SRAP primer combinations were evaluated. The number of fragments amplified from Fasciola samples using each primer combination ranged from 12 to 20, with an average of 15 polymorphic bands per primer pair. Fifty‐nine main polymorphic bands were observed, ranging in size from 100 to 2000 bp, and SRAP bands specific to F. hepatica or F. gigantica were observed. SRAP fragments common to F. hepatica and the “intermediate” Fasciola, or common to F. gigantica and the “intermediate” Fasciola were identified, excised and confirmed by PCR amplification of genomic DNA using primers designed based on sequences of these SRAP fragments. Based on SRAP profiles, unweighted pair‐group method with arithmetic averages clustering algorithm categorized all of the examined representative Fasciola samples into three groups, representing the F. hepatica, the “intermediate” Fasciola, or the F. gigantica. These results demonstrated the usefulness of the SRAP technique for revealing genetic variability between F. hepatica, F. gigantica and the “intermediate” Fasciola, and also provided genomic evidence for the existence of the “intermediate” Fasciola between F. hepatica and F. gigantica. This technique provides an alternative and a useful tool for the genetic characterization and studies of genetic variability in parasites.     

Determination of tobramycin in human serum by capillary electrophoresis with contactless conductivity detection

A study on the determination of the antibiotic tobramycin by CE with capacitively coupled contactless conductivity detection is presented. This method enabled the direct quantification of the non-UV-absorbing species without incurring the disadvantages of the indirect approaches which would be needed for optical detection. The separation of tobramycin from inorganic cations present in serum samples was achieved by optimizing the composition of the acetic acid buffer. Field-amplified sample stacking was employed to enhance the sensitivity of the method and a detection limit of 50 microg/L (S/N = 3) was reached. The RSDs obtained for migration time and peak area using kanamycin B as internal standard were typically 0.12 and 4%, respectively. The newly developed method was validated by measuring the concentration of tobramycin in serum standards containing typical therapeutic concentrations of 2 and 10 mg/L. The recoveries were 96 and 97% for the two concentrations, respectively.     

A possible explanation of the knee of cosmic light component spectrum from 100 TeV to 3 PeV

A mixed hydrogen and helium(H + He) spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H + He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants(SNRs) in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.     

基于增益光纤长度优化的双波长运转掺铒光纤锁模激光器

构建了可自启动的双波长运转掺铒光纤锁模激光器.通过优化增益光纤长度,利用掺铒光纤在1530nm附近的再吸收效应调节激光器的增益谱,使激光器在1530nm和1560nm附近具有相同的增益强度.实验中采用31cm掺铒光纤作为增益光纤,以透射式半导体可饱和吸收体作为锁模器件,实现了自启动双波长锁模运转.激光器锁模输出重复频率为58.01MHz,信噪比为58.2dB,最高输出功率为4.8mW.锁模输出的光谱在1532.4nm和1552.3nm处具有两个强度接近的谱峰,谱峰间距约为20nm.该激光器无需手动调节即可实现双波长运转,更便于实际使用.     

InP/InGaAsP多量子阱自发辐射谱的解析函数

利用洛伦兹线型函数、高斯线型函数和Sech线型函数对InP/InGaAsP多量子阱自发辐射谱进行拟合,采用莱文贝格-马夸特算法,得到上述三种函数的解析表达式.研究结果表明:高斯线型光谱拟合函数的中心波长为1548.651nm,谱线半极大全宽度为61.42 nm,功率补偿为0.00212 mW,拟合优度为0.99191,残差平方和为2.26505×10~(-6).高斯线型拟合的拟合优度最大,残差平方和最小,且各数据点的残差值分布在±0.0001之间,分布比较均匀.高斯线型函数具有较高拟合度.     

F8BT：P3HT共混薄膜的放大自发辐射

研究了聚合物poly（9,9-dioctylfluorene-co-benzothiadiazole）（F8BT）和poly （3-hexylthiophene）（P3HT）共混薄膜的放大自发辐射（ASE）现象,对影响其阈值的两个因素--增益和损耗进行了详细的研究。结果显示,共混聚合物的发光效率随着P3HT所占比例的增加有所降低。当P3HT比例低于20%时,发光效率降低不多,而其损耗则随着P3HT的增加显著减小。F8BT和P3HT混合后,光损耗系数从7.8 cm^-1下降到4 cm^-1左右。这表明F8BT：P3HT共混聚合物光波导的ASE阈值降低主要是由于其损耗的降低而导致的。ASE阈值的降低预示该材料体系容易实现电泵浦激光。     

交叉增益调制型波长转换器噪声特性的研究

对基于半导体光放大器的交叉增益调制型波长转换器相向和同向两种工作方式进行了研究。实验上分别实现了两种工作方式在1550nm波段的波长转换,比较了相同外部条件下两种工作方式的噪声特性,在全面考虑放大自发辐射噪声及其消耗载流子,增益谱的色散性和有源区内部损耗等因素的基础上,运用放大器的分段模型,计算了不同条件下两种方式的输出噪声功率,结果表明：相向型工作方式受放大自发辐射噪声的影响要远大于同向工作方式,输出放大自发辐射噪声功率的大小主要取决于载流子浓度的高低,而载流子空间分布的不均匀程度则决定两种工作方式输出噪声功率的差值大小。     

一种自交联聚合物的合成及其在水显影化学增幅型负性抗蚀剂中的应用

本文引入单体MAGME合成了具有自交联作用的MAGME、苯乙烯和N(4 羟基苯基)马来酰亚胺的共聚物,并以该聚合物为基体树脂,研制了一种新型的水显影化学增幅型负性抗蚀剂,并初步研究了其光刻工艺条件.     

鲫鲤杂交F1及其亲本RAPD标记

用RAPD技术对红鲫(♀)×野鲤(♂)及其F1个体进行了研究．15个引物在鲤鱼中扩增出86条带(33条具多态性),红鲫75条带(24条呈多态性),两者共享25条(16条呈多态性)．F