三正辛胺棉富集分离原子吸收光谱法测定金

论述了三正辛胺棉的制备及吸附金的条件和解脱方法。采用火焰原子吸收法进行测定。方法的测定范围为0.2-40g/t，相对标准偏差为2.3%，将该法用于制定黄铜矿中的金，其结果与传统的泡沫塑料富集-硫脲解脱原子吸收法测定结果一致，而本法分离效果好，测定速度快，操作简便。     

小试金富集ICP-AES法同时测定试样中的铂、钯、金

文章报道了用小试金富集ICP AES法同时测定试样中的铂、钯和金 ,将 1 0～ 2 0g试样中的铂、钯、金富集在毫克量的银合粒中 ,制成溶液后用ICP AES法同时测定铂、钯和金。该方法的检出限 (μg·mL-1 )Pt,Pd ,Au分别为 0 0 1 ,0 0 0 5 ,0 0 1 ,相对标准偏差 (RSD ,n =1 0 )分别为 0 1 % ,0 1 2 % ,0 0 9% ,标准回收率均在 97%以上。生产实践表明 ,本方法是一种快速、简便、准确的分析方法 ,已被我们应用于测定样品中的铂 ,钯和金     

铜锍及含铜烧结物料中金含量测定方法的研究

铜锍及含铜烧结物料经焙烧除硫后,用王水分解,聚氨酯泡沫塑料吸附富集分离试样中金,硫脲解脱后,分别采用电感耦合等离子原子发射光谱法(ICP-AES)和火焰原子吸收光谱(FAAS)法测定金含量.针对该类物料基体复杂的特点,对影响测定结果的各种条件进行了优化实验,确定了最佳分析条件.结果表明:采用两种方法测得12个进口铜锍及含铜烧结物的实际样品的金含量无明显差异,具有较高的准确度和精密度,能够较好地解决铜锍及含铜烧结物巾金含量测定难的问题.     

原子吸收法测定高铁试样中痕量金

在测定某铁矿中痕量金时,我们采用泡沫塑料预富集金,发现结果明显偏低。为此,我们对高铁试样中痕量金的吸附条件进行了试验。一、实验部分(一)仪器、试剂及工作条件金标准溶液:按常法配成每毫升含金1毫克的王水(1 4)贮备液。再逐级稀释成每毫升含金100微克和10微克的工作液。泡沫塑料吸收装置:将泡沫塑料切成φ16×50毫米的园柱,在"两级"(上段为φ28毫米,下段φ14毫米)玻璃吸附柱底部装一活动底板,垫一层2毫米滤纸浆,将泡沫柱装入吸附柱内,上面与布氏漏斗相接,调节流速10毫升/分。     

荧光法同时测定饲料及食品中V.A和V.E

用石油醚(30°～60℃)作抽提剂和萃取剂,借乙醇介质中的抗坏血酸使V.E避免氧化;用60%的硫酸抑制V.A对V.E的干扰作用。用荧光法分別在λ_(EX)295nm/λ_(EM)340nm和λ_(EX)340nm/λ_(EM)480nm处简便、快速地测定饲料和食品中V.A和V.E含量。样品不需经充氮皂化和柱分离,即可得到满意的结果。测定V.A和V.E的相对标准偏差分别为3.59%和1.76%,V.A和V.E的平均回收率分别为95.74%和95.05%。     

V棱镜法中入射光线垂直误差的分析

<正> 用V棱镜折射仪测量玻璃折射率,首先要校正好仪器的零位,即将标准块放入V形槽内,调整仪器,使读数显微镜中的读数为0°0′,用公式n~2=n_0~2+sinθ_0(n_0~2-sin~2θ_0)~(1/2) (1)即可算出样品折射率n,公式(1)的条件是     

泡塑负载TRPO分离富集微量金

将三烷基氧化膦(TRPO)负载在泡沫塑料上制得了TRPO负载泡塑。以火焰原子吸收光谱法(FAAS)为检测手段,研究了负载泡塑对微量金的静态吸附性能。建立了负载TRPO泡塑分离富集-FAAS测定微量金的方法。方法精密度(RSD,n=10)在1.23%—8.22%之间,通过对标准物质的分析,测量值与标准值基本一致。     

先兆型铁电体CaTiO3的第一性原理研究

在广义梯度近似 (GGA)下利用全电势线性化的缀加平面波法 (FPLAPW )计算了钛酸钙 (CaTiO3 )的电子结构 .将实验测得的晶胞体积记为V0 ,计算中所用的晶胞体积记为V .当V/V0 =1.0时 ,Ti离子位移为零相应于总能量低能态 ,钛酸钙不会发生铁电相变 .但如果其体积膨胀 10 % ,则Ti离子的位移将导致能量极小值 .这意味着在立方钛酸钙中有发生铁电相变的趋势 ,表明在钛酸钙中存在着体积诱发的铁电相变 ,即钛酸钙为先兆型铁电体 .态密度在V/V0 =1.1时 ,Tid电子和O(2 ) p电子之间存在强烈的轨道杂化 ,这种杂化是出现铁电性的必要条件 .电场梯度的结果也表明了这一点 .     

恒温电热板湿法消解-ICP-AES对地质样品中铌和钽的连续测定

通过恒温电热板加热,用硝酸-氢氟酸-硫酸(体积比为6:5:1,V/V/V)混合酸消解试样,酒石酸定容后用电感耦合等离子体-原子发射光谱法对铌钽矿石中的铌钽连续测定,所加试剂引起的干扰通过空白实验予以消除。铌、钽谱线的发射强度与x(Nb2O5)和x(Ta2O5)在0—8μg/mL的范围内呈良好的线性关系。方法的检出限分别为0.021、0.048μg/mL,方法用于地质样品中铌、钽的分析,加标回收率为95.6%—108.3%,铌和钽的相对标准偏差(n=6)为0.21%—1.56%;用于标准样品分析,测定值与认定值相符。此方法很好的解决了地质调查样品的批量大并要求快速出结果的难题。     

全微机化极谱法测定地质样品中Ag的方法探讨

地质试样用盐酸、硝酸分解 ,在湿盐状态下加入盐酸、氯化铵及氨水 ,在此底液中进行银的极谱测定 ,峰电位约为 - 0 .2 8V(对饱和甘汞电极 )。银含量在 0 .0 0— 0 .4 0 mg/ m L之间时 ,峰高与浓度呈线性关系。测定范围 0 .0 5 0 %— 2 0 .0 0 %。     

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.     

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.