多壁碳纳米管固相微萃取测定水中的三唑酮和噻嗪酮

将多壁碳纳米管涂在不锈钢丝上制作了固相微萃取探头,利用固相微萃取-气相色谱-质谱联用技术测定湖水中的三唑酮和噻嗪酮。对萃取温度、萃取时间及离子强度等影响萃取效率的因素进行了优化。在优化的条件下,通过加标水样的分析对方法进行了评估。结果表明,方法的线性范围为25—150μg/L,相关系数为0.9922—0.9982,三唑酮和噻嗪酮的检出限（LOD,S/N=3）分别为2.21ng/L和0.18ng/L。湖水的加标回收率在84%—110%之间,相对标准偏差小于10.8%。     

丙酮和乙醇双水相萃取、荧光法测定痕量维生素B2

诸如乙醇、丙酮和乙腈等水溶性小分子有机溶剂在盐的作用下能够形成双水相体系用于目标物质的萃取.正是基于此,提出了丙酮-盐-水和乙醇-盐-水体系双水相萃取、荧光测定痕量维生素B2的新方法.研究了盐和有机溶剂种类及用量、萃取时间、共存物和酸度等的影响.发现,丙酮-(NH4)2SO4-H2O和乙醇-(NH4)2SO4-H2O体系对维生素B2的一次性萃取率分别为97.6%～98.4%和94.2%～95.5%;在最适条件下,两种体系测定维生素B2的线性范围分别为1.5×10-7～3.5×10-6 mol·L-1和2.0×10-7～1.5×10-6mol·L-1,检出限分别为0.031和0.041 μg.该方法已成功用于片剂和注射液中维生素B2的测定,相对标准偏差1.5%～2.2%,与中国药典方法对照,相对误差-1.8%～1.1%.与传统的液-液萃取和固相萃取比较,本方法具有操作简便、萃取率高、干扰小、低毒等显著特点.     

氢化物发生-原子荧光光谱法同时测定纺织品中痕量砷和汞

本文以模拟汗液 (酸性、碱性 )和唾液萃取样品 ,断续流动 -无色散氢化物发生原子荧光光谱法同时测定纺织品中的微量砷、汞。研究了不同萃取介质、酸度、还原剂浓度、共存元素以及载流流速对氢化物发生的影响。方法快速、基体干扰少、灵敏度高、检出限低。本方法的线性范围为 As:1.0 0— 2 0 0 μg· L-1,Hg:0 .5 0— 2 0 μg· L-1,检出限为分别为 0 .0 3μg· L-1和 0 .0 1μg· L-1,回收率为 89.4 %— 10 0 .5 % ,精密度为 1.32 %— 5 .4 5 %。     

浊点萃取-分光光度法测定水环境中的痕量钴

利用阴离子表面活性剂十二烷基硫酸钠(SDS)和络合剂1-(2-吡啶偶氮)2-萘酚(PAN),加入HCl使SDS质子化,对钴进行浊点萃取,分光光度法测定水体中痕量钴。详细探讨了影响浊点萃取及测定灵敏度的因素。优化条件为:NaCl、HCl、PAN、SDS浓度分别为1.90mol/L、1.20mol/L、0.3μmol/L、1.25%,60℃水浴50min、离心5min(3000r/min)。在最佳条件下,钴的富集倍数为50倍,方法检出限为2.870μg/L,线性范围为16.7—83.3μg/L,RSD为0.96%—3.30%。该方法用于实际水样钴的富集和测定,结果令人满意。     

石墨炉原子吸收法测定贵金属：（四） 岩石矿物中超痕量钯铂的测定

本文提出了用0.5ml N-正辛基苯胺-间二甲苯萃取岩石矿物中超痕量钯铂的石墨炉原子吸收分析方法。对萃取钯铂的条件、其它离子的干扰情况以及在HGA-500型石墨炉中测定钯铂的最佳条件进行了研究。样品用盐酸过氧化氢分解后,溶液进行萃取,有机相直接测定。大量的其它离子不干扰测定。方法的绝对灵敏度釲为5.5pg/1%吸收、铂为40pg/1%吸收,可检测0.0001g/t的钯及0.0005g/t的铂。对含钯0.002g/t 0.006g/t铂矿样重复溶解样品测定11次,其相对标准偏差分别为钯4.9%、铂5.6%。     

微波辅助稀硝酸萃取-ICP-OES同时测定纺织品中九种有害元素

纺织品在加工的过程中会引起多种有害元素的污染,为了监控纺织品的质量,建立了微波辅助稀硝酸萃取结合电感耦合等离子体发射光谱同时测定纺织品中砷、锑、铅、镉、铬、钴、铜、镍、汞等九种有害元素的检测新方法。通过萃取剂的筛选和萃取条件的优化,最终确定了用5%的硝酸30mL作为萃取剂,萃取时间为5min,萃取温度为120℃,仪器功率为400W作为微波辅助萃取条件。并用电感耦合等离子体发射光谱对萃取出的九种有害元素总量进行检测。结果显示:本方法的检出限在2.25～112.5μg.kg-1之间,对加标样品的萃取率为73.6%～105%,相对标准偏差(RSD,n=3)为0.2%～1.7%。本方法已成功用于棉布、毛料、涤纶、腈纶四种纺织品样品的检测。     

HS-SPME-GC/MS测定饮用水中三卤甲烷分析条件的优化

对顶空固相微萃取 -气相色谱 /质谱联用测定饮用水中三卤甲烷的分析条件如固相微萃取的萃取时间、萃取温度、溶液的离子强度及 p H值等进行了优化。该方法的线性范围为 5— 15 0 μg/ L,相对标准偏差为 5 .4 %— 8.2 %。     

超声提取-反相高效液相色谱法测定黄姜中薯蓣皂甙元

以超声萃取-酸水解-超声萃取进行预处理,结合RP-HPLC测定黄姜中薯蓣皂甙元含量。色谱条件为:采用AglilengtHC-C18色谱柱,流动相为甲醇∶水=95∶5(V∶V),流速为1.0mL/min,UV检测波长为203nm。结果表明,在40—1000μg/mL范围内,薯蓣皂甙元峰面积与其质量浓度具有良好的线性关系(r=0.9996),样品平均加标回收率为99.8%,RSD为1.1%。与直接酸水解-萃取预处理方式进行对比,本方法测得薯蓣皂甙元含量提高了32%。采用本方法对黄姜芽,根茎,表皮及不定根中的薯蓣皂甙元含量进行测定:根茎1.69%,芽0.19%,表皮0.15%,不定根部分含量为0.36%。     

不同物理场处理对磷脂分散体系的影响

利用动态光散射研究了脉冲电场、超声波、微射流3种物理场处理对磷脂分散体系的颗粒性质及稳定性的影响。结果表明:当施加的处理条件分别为60kV/cm脉冲电场、500 W超声波及130 MPa微射流时,磷脂的平均粒径由594.4nm分别减小至259.2、88.7和37.8nm;静置24h后,脉冲电场处理样的粒径恢复得较好,而超声波和动态高压微射流处理样基本不恢复。说明维系细胞膜结构与流动性功能的磷脂的粒径随外加物理场能量的输入而逐渐减小,高强脉冲电场处理比较柔和,处理后磷脂粒径的变化表现出较强的可逆性,与脉冲电场对生物细胞膜影响的可逆性相对应。     

微波萃取-分光光度法研究关黄柏中小檗碱的提取

微波萃取是利用微波能来提高萃取率的-种新技术,用正交法优化微波萃取条件,与传统的酸碱法浸提小檗碱进行了对比研究,确定了微波萃取技术用于中药关黄柏中提取小檗碱的工艺条件.结果表明,使用微波萃取的优化条件为:80℃萃取温度,固液比为1:15,时间1.5min,传统溶剂法:萃取温度70℃,固液比为1:20,时间24h,与稀硫酸浸泡提取法相比,微波萃取工艺提取时间大大缩短,产量可提高30%,工艺操作简便、省时、节能,易于控制.     

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.     

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.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.