分光光度法测定环境水样中的汞

研究了氯磺酚偶氮硫代若丹宁 ( HSCT)与汞的显色反应 ,在醋酸介质中 ,HSCT与汞反应生成 2∶ 1稳定络合物 ,λmax=5 4 5 nm,ε=5 .66× 10 4 L· mol-1· cm-1。汞含量在 0— 2 .5μg/ m L范围内符合比耳定律 ,本方法可用于水样中痕量汞含量的测定     

微波消化-分光光度法测定铂

在盐酸介质中对氨基苯基亚甲基若丹宁 (ABR)与铂的显色反应 ,生成 2∶ 1稳定络合物 ,λmax=5 2 5 nm,ε=5 .98× 10 4L·mol-1·cm-1。铂含量在 0— 5 0 μg/ 2 5 m L范围内符合比耳定律 ,方法可用于催化剂中铂含量的测定。     

4-(2-羟基-4-硝基苯偶氮)-1-苯基-3-甲基吡唑啉酮光度法测定烟草中镁

研究了 4 - (2 -羟基 - 4-硝基苯偶氮 ) - 1-苯基 - 3-甲基吡唑啉酮 (HNAPMP)与镁的显色反应 ,在 p H=10的硼砂 -氢氧化钠缓冲介质中 ,HNAPMP与镁反应生成 2∶ 1稳定络合物 ,λmax=5 2 2 nm,ε=3.5 8× 10 4L·mol-1· cm-1。镁含量在 0— 2 0 μg/2 5 m L范围内符合比耳定律 ,方法用于烟草样品中镁含量的测定 ,结果令人满意     

2-(2''-喹啉偶氮)-5-二甲氨基苯甲酸光度法测定钢铁中的钴

合成了新试剂 2 - (2’-喹啉偶氮 ) - 5 - N,N-二甲氨基苯甲酸 (QADMAB) ,并研究了其与钴的显色反应 ,在 p H=4 .0的 KH2 PO4- K2 HPO4缓冲介质中 ,CTMAB存在下 ,QADMAB与钴反应生成 2∶ 1稳定配合物 ,λmax=6 2 0 nm,ε=1.2 5× 10 5L·mol-1· cm-1。钴含量在 0— 0 .4 mg/ L范围内符合比耳定律 ,方法用于钢铁样品中钴含量的测定 ,结果令人满意     

山奈黄素光度法测定烟草样品中的铝

本文研究了山奈黄素与铝的显色反应 ,在 p H=5 .6 HAc- Na Ac缓冲介质中 ,有 CPB存在下 ,山奈黄素与铝反应生成 3∶ 1稳定络合物 ,λmax=42 5 nm,ε=1 .6 3× 1 0 4 L· mol- 1 · cm- 1 。铝含量在 0— 2 0μg/2 5 m L内符合比耳定律 ,方法用于烟草样品中铝含量的测定 ,结果令人满意。     

对磺酸基苯基亚甲基若丹宁光度法测定环境水样中的汞

研究了对磺酸基苯基亚甲基若丹宁 (SBDR)与汞的显色反应 ,在 p H为 4 .0的 HAc- Na Ac缓冲介质中 ,SBDR与汞反应生成 2∶ 1稳定络合物 ,λmax=5 10 nm,ε=8.16× 10 4 L· mol-1· cm-1。汞含量在 0—30 μg/ 2 5 m L范围内符合比耳定律 ,方法用于环境水样中汞含量的测定 ,结果令人满意     

对乙酰基偶氮氯膦光度法测定烟草中钙的方法研究

研究了对乙酰基偶氮氯膦 ( ACCPP)与钙的显色反应 ,在 p H=8.5的氯化铵 -氨水缓冲介质中 ,乳化剂 - OP存在下 ,ACCPP与钙反应生成 1∶ 1稳定络合物 ,λmax=680 nm,ε=4 .0 1× 10 4 L· mol-1· cm-1。钙含量在 0— 2 0μg/2 5m L范围内符合比耳定律 ,方法用于烟草样品中钙含量的测定 ,结果令人满意。     

分光光度法测定食品中的锗

在浓度为 1 .2 mol/ L的 HCl介质中 ,苯芴酮与锗反应生成橙红色络合物 ,λmax=5 30 nm,ε=3× 1 0 4 L· mol- 1 · cm- 1 ,锗含量在 0 .5 - 5 0μg/ 5 0 m L范围内符合比尔定律 ,本方法用于食品中锗的测定 ,结果令人满意。     

2-(2-喹啉偶氮)-4-甲基-1,3-苯二酚光度法测定铜的研究

合成了新试剂 2 - (2 -喹啉偶氮 ) - 4-甲基 - 1,3-苯二酚 (QAMDHB) ,并研究了其与铜的显色反应 ,在 p H=2 .2的磷酸 -磷酸二氢钾缓冲介质中 ,溴化十六烷基三甲基胺 (CTMAB)存在下 ,QAMDHB与铜反应生成 2∶ 1稳定络合物 ,λmax=5 5 0 nm,ε=4 .84× 10 4L· mol-1· cm-1。铜含量在 0— 2 0μg/ 2 5 m L范围内符合比耳定律 ,方法用于环境水样中铜含量的测定 ,结果令人满意     

新亚铜灵试剂光度法测定烟草中的铜

研究了在 Emulsifier- OP存在下新亚铜灵试剂 (NHCM)与铜的显色反应 ,在 p H为 4.5的 HAc- Na Ac缓冲介质中 ,Emulsifier- OP存在下 ,NHCM与铜反应生成 2∶ 1稳定络合物 ,λmax=46 0 nm,ε=1 .6 4× 1 0 4 L·mol- 1 ·cm- 1 。铜含量在 0— 5 0 μg/2 5 m L 范围内符合比耳定律 ,该方法用于烟草中铜含量的测定 ,结果令人满意。     

Rb蒸气中的5PJ+5PJ′→5S+5DJ″碰撞能量合并

研究了Rb(5PJ) Rb(5PJ′)→Rb(5S) Rb(5DJ″)的碰撞能量合并过程,一台单模半导体激光器共振激发Rb原子的5P1/2或5P3/2态,另一与泵浦激光束反向平行的单模激光束作为吸收线探测激发态原子密度及其空间分布,吸收线分别调至5P1/2→5D3/2和5P3/2→7S1/2跃迁,由激发态原子密度和谱线荧光比得到碰撞能量合并过程5PJ 5PJ′→5S 5DJ″的截面.两台激光器同时分别激发5P1/2和5P3/2态,通过对5DJ″→5PJ的荧光探测,得到5P3/2 5P1/2碰撞转移到5D5/2和5D3/2的截面分别为(1.12±0.50)×10-14和(1.01±0.45)×10-14cm2.     

On the kinetics of the C5H5 + C5H5 reaction

The possibility that the reaction between two cyclopentadienyl radicals (cC₅H₅) may lead to the production of naphthalene has been the subject of considerable theoretical and experimental studies. Though it has been proposed that this reaction may be the main channel for the formation of naphthalene in many combustion environments, the elementary mechanism leading from the initial adduct (C₅H₅_C₅H₅) to naphthalene is still not clear. In this study the portion of the C₁₀H₁₀ PES accessible to C₅H₅_C₅H₅ has been theoretically re-examined using density functional theory to locate stationary points and the CBS-QB3 computational protocol to determine energies. A new reaction pathway leading to the formation of a set of azulyl radicals was identified. Since it is known that azulyl radicals can easily decompose to naphthalene and atomic H, the proposed pathway provides an effective route for the formation of naphthalene. Channel specific kinetic constants were determined between 1100 K and 2000 K integrating the master equation for a PES comprising both this reaction pathway and the literature reaction pathway, which main product is the fulvalenyl radical. It was found that the main reaction channel is decomposition to reactants in the whole temperature range investigated and that the azulyl reaction channel is dominant over the fulvalenyl pathway up to 1450 K. The rate constants calculated at 1 bar for the azulyl and fulvalenyl reaction channels are 10^14.72T(K)^?0.853 exp(?3650/T(K)) and 10^10.30T(K)^0.951 exp(?7948/T(K)) cm³/mol/s, respectively. The rate constant for the formation of naphthalene through the azulyl channel is consistent with recent estimates based on the kinetic simulation of the pyrolysis and oxidation of cyclopentadiene.     

Facteurs de lande des niveaux des configurations 5s5p et 5s5d de cd I

A plane Fabry-Pérot is used to measure, with a precision of about 10^-4, the Landé factor of the levels issued from the 5s5p and 5s5d configurations of cadmium I. Calculations taking into account intermediate coupling effects and the anomalous gyromagnetic ratio of the free electron are insufficient to explain some experimental data; in such cases it is necessary to perform a more detailed analysis of the corrections due to the relativistic effects.     

Two-Brane Randall-Sundrum Model in AdS 5 and dS 5

Two flat Randall-Sundrum three-branes are analyzed, at fixed mutual distance, in the case where each brane contains an ideal isotropic fluid. Both fluids are to begin with assumed to obey the equation of state p = ( – 1), where is a constant. Thereafter, we impose the condition that there is zero energy flux from the branes into the bulk, and assume that the tension on either brane is zero. It then follows that constant values of the fluid energies at the branes are obtained only if the value of is equal to zero (i.e., a vacuum fluid). The fluids on the branes are related: if one brane is a dS ₄ brane (the effective four-dimensional constant being positive), then the other brane is dS ₄ also, and if the fluid energy density on one brane is positive, the energy density on the other brane is larger in magnitude but negative. This is a non-acceptable result, which sheds some light on how far it is possible to give a physical interpretation of the two-brane scenario. Also, we discuss the graviton localization problem in the two-brane setting, generalizing prior works.     

Ti5O5 superstructures of cubic titanium monoxide

A cubic model is proposed for the Ti₅O₅ (Ti₅?O₅□ ≡ Ti₉₀?₁₈O₉₀□₁₈) superstructure of nonstoichiometric titanium monoxide Ti _x O _z with double imperfection. The unit cell of the cubic Ti₅O₅ superstructure has the threefold lattice parameter of the unit cell of the basis disordered B1 structure of Ti _x O _z monoxide and belongs to space group $Pm\bar 3m$ . The channel of the disorder-order transition, i.e., Ti _x O _z (space group $Fm\bar 3m$ )-Ti₅O₅ (space group $Pm\bar 3m$ ), includes 75 superstructure vectors of seven stars {k ₁₀}, {k ₇}, {k ₆₍₁₎}, {k ₆₍₂₎}, {k ₄₍₁₎}, {k ₄₍₂₎}, and {k ₁}. The distribution functions of Ti and O atoms over the sites of the cubic Ti₅O₅ superstructure are calculated. A comparison of the X-ray and electron diffraction data obtained for ordered TiO_1.087 monoxide with the theoretical simulation results supports the existence of the cubic Ti₅O₅ superstructure. The cubic (space group $Pm\bar 3m$ ) Ti₅O₅ superstructure is shown to be a high-temperature structure relative to the well-known monoclinic (space group C2/m) superstructure of the same type.     

Thermomagnetic history effects in LaCo5xNi5−5x and ThCo5xNi5−5x compounds

The magnetization versus temperature curves of several compounds of the series LaCo_5xNi_5?5x were found to give rise to an abrupt increase at temperatures being higher in accordance as the applied field strengths are smaller. The magnetic properties strongly depend on the magnetic as well as on the thermal history. The observed magnetic behaviour is discussed in terms of mictomagnetism and narrow Block wall propagation.     

Corrosion of 85-5-5-5 bronze in natural and synthetic acid rain

In order to investigate the decay of bronzes exposed to acid wet depositions, a comparative study has been performed by following the corrosion behaviour of different sets of bronze specimens exposed either to natural rain or to a similar solution, without organic compounds, artificially reproduced in laboratory. The as cast G85 bronze specimens were exposed to aggressive solutions for different periods through a wet-dry technique. The pH trend of the solutions and the amount of metals transferred into the solutions were periodically monitored. OM, SEM, XRD, RAMAN analyses and ac electrochemical measurements were performed on the artificially weathered specimens. Preliminary results, showing the difference between the ageing in natural and synthetic rain, suggest the influence of the organic components on the corrosion process. In particular, the growth of a more uniform protective layer of corrosion products on the metal surface exposed to the natural rain could be attributed to these components. PACS 82.45.Bb; 82.33.Tb