An ASE Reduction Filter Using Cascaded Optical Fiber Grating Couplers in EDFA Repeater

A new configuration for an ASE reduction filter in EDFA repeaters for WDM optical transmission systems using optical fiber grating couplers (FGCs) was proposed and first demonstrated. The filtering characteristics of the proposed filter for amplified single wavelength signal and 2-channel WDM signals using EDFA were identified. It was found that the filter was effective to improve SNR in optical domain by reducing ASE noise. The required FGC characteristics for the filter were theoretically predicted under the condition that the total filter loss did not exceed 3 dB. More than 70% of drop efficiency was required in each FGC for the application of the proposed filter to an 8-channel WDM system using EDFA repeaters.     

基于新型长周期光纤光栅的掺铒光纤放大器

报道了基于高频CO₂激光脉冲写入的新型长周期光纤光栅的低噪音掺铒光纤放大器,这种新型长周期光纤光栅是用大约几千Hz的高频CO₂激光脉冲对光纤玻璃热冲击作用而形成的.在铒纤中插入一个长周期光纤光栅,会明显减少掺铒光纤放大器的放大自发辐射(ASE)噪音.报道了两种低噪音掺铒光纤放大器,作为前置放大器和线路放大器,它们的ASE噪音指数分别从4.0 dB减少到3.5 dB和从4.8 dB减少到4.3 dB,并且在作为线放时,其小信号增益从30 dB提高到37 dB,降噪及提高增益效应十分显著.     

神光装置放大自发辐射输出特性测量

讨论了大型激光装置放大自发辐射输出的一般特性，给出了神光装置放大自发辐射特性的测量结果。     

Using three major criteria to evaluate aromaticity of five-member C-containing rings and their Si-, N-, and P-substituted aromatic heterocyclics

In this paper, we used bond-length equalization, aromatic stabilization energies (ASE) and nucleus-independent chemical shifts (NICS), calculated with (density functional theory) B3LYP levels at the 6-311+G^** basis set, to evaluate the aromaticity of a set of 38 five-member planar π-electron aromatic systems: sila-, aza- and phospha- derivatives and their parent systems. The result revealed statistically significant correlations among the above three criteria, and the order of aromaticity of the whole set was: Aza- derivatives rings > Phospha- derivatives rings > Sila- derivatives rings > Carbon-containing rings; NICS(0.6) and NICS(0.8) had the same results in evaluating the order of aromaticity in our case.     

加速溶剂萃取同步净化-同位素内标-气相色谱-高分辨质谱测定水产品中32种多氯联苯

建立了加速溶剂萃取同步净化-同位素内标-气相色谱-高分辨质谱同时测定水产品中32种多氯联苯含量的方法。通过在加速溶剂萃取仪中加入2 g无水硫酸钠、1 g弗罗里硅土、50 g中性氧化铝作为吸附剂实现同步净化的效果，萃取溶剂为二氯甲烷-正己烷（1:1，v/v），萃取温度为100℃，循环2次。萃取结束后分别用0.5 mL浓硫酸净化两次，净化液浓缩定容后，采用气相色谱-高分辨质谱测定，同位素内标法定量。32种多氯联苯在0.1~20 μg/L范围内平均相对响应因子（RRF）的相对标准偏差（RSD）值（n=7）均小于15%，定量限（S/N=10）为0.3~1.9 ng/kg。在草鱼和海鲈鱼空白基质中做加标回收试验，添加水平为5、20和50 ng/kg，得到的平均回收率为71.9%~119.0%（n=6），RSD为3.5%~19.6%。该方法背景干扰低，灵敏度高，重现性好，回收率稳定，适用于水产品中多氯联苯的检测。     

Determination of synthetic musks in the sediment of the Taihu lake by using accelerated solvent extraction (ASE) and GC/MS

Synthetic musks, substitutes for natural musks, are widely distributed in environment. They have been detected in water, sludge, fish, shrimp, mussels and other aquatic animals, and even in human's adipose tissue, blood and breast milk. In this study, a new extraction procedure, based on the accelerated solvent extraction (ASE) and in cell clean-up technique was developed and successfully coupled with gas chromatography-mass spectrometry (GC/MS) for the analysis of musks in sediment samples. With this method, the limits of detection as low as 0.03–0.05?ng?g^?1 and the recovery rate of 86.0%–104% are achieved. When compared with soxhlet extraction (SE) and ultrasonic extraction (USE), ASE not only has the best extraction efficiency but also has advantage in extraction time and solvent consumption. Eight synthetic musks, including six polycyclic musks (Tonalide (AHTN), Galaxolide (HHCB), Phantolide (AHDI), Traseolide (ATII), Cashmeran (DPMI) and Celestolide (ADBI)) and two nitro musks (musk xylene (MX) and musk ketone (MK)), were evaluated in sediment samples collected from 15 selected locations of the Taihu lake, one of the largest freshwater lakes in China. The contents of synthetic musks in sediment samples range from 0.336 to 3.10?ng?g^?1 for HHCB, 0.184 to 1.21?ng?g^?1 for AHTN, below detection limit (BDL) to 0.349?ng?g^?1 for MX, and BDL to 0.0786?ng?g^?1 for MK. The contents of DPMI, ADBI, AHMI and ATII are below detection limit in all samples. The results reflect current status of fragrance compound pollution in this area, and provide basic data for environmental policy making.     

加速溶剂提取-同位素稀释-高分辨气相色谱-高分辨质谱法测定生物样品中82种多氯联苯

我国水产品中多氯联苯(PCBs)的检测方法,主要以6种指示性PCBs和12种二噁英类共平面PCBs为主,仅涵盖有限的PCBs。为更全面地获得生物体中PCBs的浓度水平,深入探讨PCBs在生物体内的代谢和富集特征,进而准确评价PCBs对人类的暴露水平及风险,以鱼和贝类作为生物样品代表,建立了加速溶剂提取-同位素稀释-高分辨气相色谱-高分辨质谱(ASE-ID-HRGC-HRMS)测定生物样品中82种PCBs的方法。比较了振荡提取和加速溶剂提取两种提取方式的回收率和重复性,最终采用正己烷-二氯甲烷(1∶1, v/v)对PCBs进行加速溶剂提取。考察了各流分淋洗液对PCBs的回收率,确定了样品提取液经8 g 44%酸性硅胶层析柱(内径15 mm), 90 mL正己烷洗脱的净化方式。样品提取液净化浓缩后进行HRGC-HRMS分析,色谱柱采用DB-5MS超低流失石英毛细管柱(60 m×0.25 mm×0.25 μm)。通过优化后的升温程序对化合物进行分离,以保留时间和两个特征离子精准定性,采用同位素内标法定量。结果表明,在0.1~200 μg/L范围内,平均相对响应因子(RRF)的相对标准偏差值(RSD, n=7)均≤20%,相关系数(r²)>0.99。生物样品中PCBs的方法检出限为0.02~3 pg/g;鱼类中PCBs平均加标回收率为71.3%~141%, RSD(n=7)为2.1%~14%;贝类中PCBs平均加标回收率为76.9%~143%, RSD为1.4%~11%。该方法灵敏、准确、可靠,可以更加全面具体地分析鱼和贝类等水产品受PCBs的污染情况,为国内外开展生物监测提供有效的技术支持,从而服务于相关生态环境管理及履行《斯德哥尔摩公约》。     

加速溶剂萃取-磁固相萃取-高效液相色谱-串联质谱法测定水产品中10种氟喹诺酮类药物残留

养殖过程中的不合理使用和滥用使得水产品中氟喹诺酮抗生素残留累积量呈递增趋势,对人类的健康造成潜在的风险。建立高效、灵敏和可靠的水产品中氟喹诺酮类药物的同时分析方法十分重要。该研究建立了加速溶剂萃取-磁固相萃取-高效液相色谱-串联质谱法(ASE-MSPE-HPLC-MS/MS)测定水产品中沙拉沙星、氧氟沙星、恩诺沙星、丹氟沙星、洛美沙星、培氟沙星、环丙沙星、依诺沙星、诺氟沙星和双氟沙星残留的检测方法。采用室温自组装法,即在室温(25 ℃)下,将氧化石墨烯和零价纳米铁储备液快速涡旋混合,磁性分离收集沉淀物,得到GO@nZVI磁性复合材料。以扫描电镜、傅里叶变换红外光谱和X-射线衍射对磁性复合材料进行表征,结果显示GO@nZVI成功制备。该材料应用于MSPE净化中,ASE萃取温度为70 ℃,萃取溶剂为甲醇,萃取压力为10.34 MPa,静态萃取时间为5 min,循环萃取3次。萃取液浓缩后经MSPE有效净化后,采用Agilent ZORBAX Eclipse Plus C18色谱柱(100 mm×3.0 mm, 1.8 μm)梯度洗脱分离,MS/MS电喷雾正离子(ESI⁺)扫描、多反应监测(MRM)模式进行定量分析。氟喹诺酮的线性范围为1~100 μg/kg,线性相关系数(r²)均大于0.9995;目标物的检出限(S/N=3)为0.02~0.29 μg/kg,定量限(S/N=10)为0.07~0.98 μg/kg。所建方法成功用于黄鱼、草鱼、黑鱼、明虾和沼虾中氟喹诺酮的测定,在1倍、2倍、10倍定量限加标水平下得到的加标回收率为81.6%~105.8%,相对标准偏差(RSD)为4.2%~13.6%。研究表明,将ASE与MSPE有机结合,利用外部磁场实现萃取液的净化,无需离心和过滤操作,溶剂用量少,并且该方法所使用磁性萃取材料制备方法简单,具有自动化程度高、简便快速、方法灵敏度高、准确度高、重复性好等特点,可满足对水产品中FQs残留限量检测要求,具有实际应用前景。     

Templated‐Assembly of CsPbBr3 Perovskite Nanocrystals into 2D Photonic Supercrystals with Amplified Spontaneous Emission

Perovskite nanocrystals (NCs) have revolutionized optoelectronic devices because of their versatile optical properties. However, controlling and extending these functionalities often requires a light‐management strategy involving additional processing steps. Herein, we introduce a simple approach to shape perovskite nanocrystals (NC) into photonic architectures that provide light management by directly shaping the active material. Pre‐patterned polydimethylsiloxane (PDMS) templates are used for the template‐induced self‐assembly of 10 nm CsPbBr₃ perovskite NC colloids into large area (1 cm²) 2D photonic crystals with tunable lattice spacing, ranging from 400 nm up to several microns. The photonic crystal arrangement facilitates efficient light coupling to the nanocrystal layer, thereby increasing the electric field intensity within the perovskite film. As a result, CsPbBr₃ 2D photonic crystals show amplified spontaneous emission (ASE) under lower optical excitation fluences in the near‐IR, in contrast to equivalent flat NC films prepared using the same colloidal ink. This improvement is attributed to the enhanced multi‐photon absorption caused by light trapping in the photonic crystal.