Fe(Ⅲ)改性海藻酸钠微球微萃取-原子荧光光谱法测定海水中As(Ⅴ)和As(Ⅲ)

首次制备了Fe(Ⅲ)改性修饰的海藻酸钠微球作为固相微萃取材料,用该微球装载的微柱能够在不同形态砷化物共存时选择性富集水样中As(Ⅴ)。结合氢化物发生-原子荧光光谱法,可以实现实际水体样中无机As(Ⅲ)和As(Ⅴ)的形态分析。具体过程为：(1)以0.1 mol·L-1柠檬酸为介质,在填充柱后流出液中选择性测定As(Ⅲ);(2)以20 g·L-1硫脲-10 g·L-1抗坏血酸溶液为预还原剂,5%盐酸为介质,测定不经过微萃取柱分离的原始水体样品中无机总砷(As(Ⅲ)和As(Ⅴ)),然后以差减法计算As(Ⅴ)的量。Fe(Ⅲ)改性海藻酸钠微球制备过程简便,成本低廉、 绿色环保,相应基于Fe(Ⅲ) 改性海藻酸钠微球微萃取过程的砷形态分离分析微萃取柱及其光谱联用技术,可以有效、 快速地测定自然水体中As(Ⅲ)和As(Ⅴ),具有实际意义。     

离子色谱-氢化物发生-原子荧光法测定含金尾矿中砷

研究了离子色谱-氢化物发生-原子荧光(IC-HG-AFS)联用测定金矿尾矿淋滤液中各种价态砷的方法。以(NH₄)₂HPO₄溶液(pH 6.00)为流动相,阴离子分离柱分离,原子荧光进行检测,As(Ⅲ)加标回收率在97%～107%、As(Ⅴ)在95%～109%之间,相对标准偏差小于4%。从测试结果和色谱分离图可以看出,该方法能够使As(Ⅲ),As(Ⅴ),MMA和DMA等四种形态的砷完全分离。检出限可达到As(Ⅲ)1.0 μg·L-1,As(Ⅴ)2.3 μg·L-1。该方法适用于金矿石、尾矿石淋出液及金矿周遍环境水体中不同价态砷和总砷的定性和定量测定。     

氢化物发生-双道原子荧光光谱法同时测定中药中不同形态的砷和锑

建立了一种氢化物发生-双道原子荧光光谱法同时测定中药中As(Ⅲ),As(Ⅴ),Sb(Ⅲ)和Sb(Ⅴ)的方法。对实验条件进行了优化,在最佳工作条件下,砷和锑的检出限分别为0.090 3和0.057 8 μg·L-1,RSD分别为2.01%和1.39%。将本法成功应用于中药样品的形态分析,As(Ⅲ)和As(Ⅴ)的回收率分别为90.8%～98.2%和89.2%～102.0%,Sb(Ⅲ)和Sb(Ⅴ)的回收率分别为89.7%～102.0% 和90.3%～110.0%。     

氢化物发生-原子荧光光谱法测定椒目中不同化学形态的砷

结合椒目化学成分的分离提取方法,采用AFS-3100原子荧光光谱法,分析了不同产地椒目中的砷含量及其形态。使用0.45 μm滤膜和混合溶剂提取的方法将椒目中的砷分为悬浮态和可溶态,并使用离子交换树脂将可溶态中的砷分为As(Ⅲ),As(Ⅴ),MMA,DMA,建立了砷的四种形态分离分析方法。结果显示,各产地椒目中均以无机砷为主且As(Ⅴ), 含量较As(Ⅲ)高,甲醇-水(4∶1)对椒目中砷的浸提率高,椒目水可煎出态总砷百分率为53.7%～62.3%。应用本方法对椒目中的砷进行形态分析,回收率在96.0%～101.3%范围内,RSD小于2.66%。表明其灵敏度高,重现性好。     

在线捕集分离联用技术对食品调料中砷形态分析方法研究

成功建立了冷捕集-气相色谱-氢化物发生-原子荧光光谱分析测定食品调料(酱油和醋)中砷形态的方法。以脱脂棉为分离介质,用液氮对样品中生成的气态砷化合物进行冷捕集,常温下不同砷形态化合物即可以实现基线分离,随后被原子荧光光谱检测。实验考查了酸介质的种类和酸度、KBH₄溶液的浓度、反应时间以及载气(He)的流量等实验条件对测定结果的影响。结果表明,在优化后的实验条件下,方法对As(Ⅲ),As(Ⅴ),MMA(Ⅴ)和DMA(Ⅴ)的检出限分别为0.2,0.2,0.3,0.8 ng·mL-1,对酱油和醋As(Ⅲ),As(Ⅴ),MMA(Ⅴ)和DMA(Ⅴ)的回收率为93.07%～103.54%。与传统的液相色谱分离方法相比,该方法不用对样品进行特殊前处理,分析速度快,灵敏度高,适合于对食品调料中砷形态尤其是无机砷形态的准确、快速分析测定。     

垃圾焚烧飞灰中砷的赋存形态研究

为实现垃圾焚烧过程中砷的释放控制,本文采集了六个地区两种炉型垃圾焚烧电厂的飞灰,通过分析飞灰中砷的赋存形态,阐释了垃圾焚烧过程中砷的迁移转化机理。结果表明,飞灰中砷总量存在一定的地域性差异,且炉排炉飞灰中砷含量高于流化床飞灰。飞灰中的As(Ⅲ)极少(0.34%~9.56%),大部分砷在高温焚烧过程中与Ca、Fe、Al等元素化合物发生交互反应以As(Ⅴ)存在于飞灰中,此外,少量砷被硅铝酸盐固化在飞灰基质中.     

HPLC-ICP-MS联用技术研究甲醇对砷形态分析结果的影响

砷是一种有毒并致癌的化学元素，普遍存在于各种环境介质和生物体中。研究表明，砷对生物体的毒性不仅与砷的浓度，还和其存在形态密切相关。因此，对砷的不同形态进行分析具有重要意义。以往的研究表明，甲醇被广泛用作固体样品砷形态分析的提取剂，一定量的甲醇可以提高ICP-MS测总砷的信号强度。但是，关于甲醇对砷形态分析结果的影响研究尚未见报道。应用高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)建立同时测定AsC，AsB，As(Ⅲ)，DMA，MMA和As(Ⅴ)等六种砷形态的优化方法。HPLC采用阴离子交换柱，30 mmol·L-1 (NH₄)₂CO₃(pH=9.3)作为流动相。选择DRC模式，以O₂为反应气体，监测91AsO+作为检测信号。方法学验证表明，六种砷形态的线性相关系数都大于0.998 9。采用不同浓度的甲醇(0～100%)作为砷形态定容溶液，发现随着甲醇浓度的增加，As(Ⅲ)和DMA的峰面积显著增加。选取对砷形态结果影响最小的25%甲醇-水作为定容溶液时，其对不同浓度的砷均有一定的影响，并且对As(Ⅲ)和DMA影响最大。因此，在今后的研究中，甲醇的去除起着重要的作用。     

流动注射氢化物发生-原子荧光光谱法测定土壤中有效态As(Ⅲ)和As(Ⅴ)

提出了一种流动注射氢化物发生 原子荧光光谱法测定土壤中有效态As(Ⅲ )和As(Ⅴ )的方法。在0 1mol·L-1柠檬酸介质 (pH =3 1)中选择性测定As(Ⅲ ) ,然后用L 半胱氨酸流动注射在线还原As(Ⅴ )后测定总砷 ,由二者之差求得As(Ⅴ )。设计了在线还原及氢化物发生流路和操作程序 ,选择了各项化学条件和流路参数。As(Ⅲ )和As(Ⅴ )的检出限 (3σ)分别为 0 11和 0 0 7ng·mL-1。对于 10ng·mL-1As(Ⅲ )溶液 ,连续7次测定得精密度 (RSD)为 1 43% ,应用于实际土壤样品的测定 ,加标回收率在 82 %～ 10 4%之间     

原子荧光光度法测定牛黄解毒片中可溶性砷(Ⅲ)和砷(Ⅴ)

用原子荧光光度法测定牛黄解毒片中可溶性砷(Ⅲ)和砷(Ⅴ)。对牛黄解毒片中可溶性砷的基体效应进行了考查,探讨了HCl酸度、还原剂NaBH4浓度对As(Ⅲ)和As(Ⅴ)的测定影响,确定了在酸性介质HCl质量分数为10％-15％,还原剂NaBH4质量分数为2.0％-2.5％时,用校准曲线法分别测定As(Ⅲ)和As(Ⅴ)与As(Ⅲ)的总量,用差减法测定As(Ⅴ)含量。对同一厂家生产的牛黄解毒片进行6次分析,As(Ⅲ)和As(Ⅴ)的相对标准偏差分别为0.80％和2.90％,As(Ⅲ)和As(Ⅴ)的加标回收率分别96.7％-103.5％和109.0％-116.8％。     

HPLC-ICP-MS研究炮制对中药砷形态的影响

应用高效液相色谱-电感耦合等离子体质谱联机技术(HPLC-ICP-MS)建立了中药中AsⅢ,AsⅤ,MMA和DMA等四种砷形态的同时测定方法,用该方法对黄芪、大黄、黄芩、何首乌、地黄等五种中药炮制前后砷形态的变化进行了比较研究,并对一个总砷超标的冬虫夏草样品进行了砷形态的分析.方法学验证表明:四种砷形态的线性相关系数(...     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.     

Design optimization of highly sensitive LSPR enhanced surface plasmon resonance biosensors with nanoholes

For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.     

Polymer gratings based on photopolymerization for low-order distributed feedback polymer lasers

Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.