The Significance of Mobilization and Immobilization of Specific Radionuclides for Optimum Bioleaching Conditions Using Aspergillus lentulus

Physics of Particles and Nuclei Letters - Gamma spectrometry is applied for measurement of natural radioactivity by Hyper-pure germanium (HPGe) systems during the application of bioleaching optimum...     

Spectral Properties of Probes Containing Benzothioxanthene Chromophore Linked with Hindered Amine in Solution and in Polymer Matrices

Absorption and emission spectroscopy as well as laser flash photolysis was employed in order to characterize the spectral properties of novel probes based on benzothioxantheneimide chromophore covalently linked with different types of sterically hindered amines. These were chosen as 2-(2,2,6,6-tetramethyl-4-piperidyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTXINH), the equivalent stable nitroxyl radical, i.e. 2-(1-oxo-2,2,6,6-tetramethyl-4-piperidyl)thioxantheno[2,1,9dej]isoquinoline 1,3-dione (BTXINO) and the alkoxy derivative 2-(1-(1′-phenylethoxy)-2,2,6,6-tetramethyl-4-piperidyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTXINOR). Spectral properties, in solutions and in various polymer matrices such as polystyrene, polymethyl methacrylate, polyvinyl chloride and polypropylene, were compared with the compound 2-(1-dodecyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTXID) taken in the present study as a reference compound. By means of the fluorescence decay and in the contrary to three other probes, BTXINO probe clearly showed a biexponential decay while the three other probes led to monoexponential decay. Two different singlet excited states with lifetimes of about 0.4 and 5 ns were proposed. They correspond to two dispositions of the nitroxyl radical chain above and along the fluorescent moiety of the molecule. Such behaviour depends on the surrounding media. Moreover, an efficient intramolecular quenching of the fluorescence emission was only observed with the short lived singlet excited state. The ratio BTXID/BTXINO was found equal to about 4 and 9 in solutions and polymer matrices respectively. Laser flash photolysis indicated that the novel probes as well as the model compound yielded transient absorption with maximum at 530 nm, corresponding to the triplet states. The intermolecular quenching of such species by molecular oxygen and by free N-oxyl, such as 1-oxy-2,2,6,6-teramethylpiperidine (TEMPO) and 1-oxy-2,2,6,6-teramethyl-4-hydroxypiperidine (TEMPOL), and the intramolecular quenching was not efficient.     

Photoacoustic characterization of optical and thermal properties of CdSe quantum dots

We report on the optical absorption properties of as prepared CdSe quantum dots (QDs) measured by the photoacoustic (PA) method. CdSe QDs were fabricated by the chemical solution deposition (CD) technique. With increasing growing time, the redshift of the PA spectra can be clearly observed and optical absorption in the visible region due to CdSe Q-dots is demonstrated. The average diameters of the CdSe QDs for each growth time interval is estimated using the effective mass approximation giving diameters ranging from 2.6 nm to 3.4 nm. These values are comparable to those obtained by scanning tunnelling microscope (STM). Thus, PA spectroscopy is useful to obtain the QDs sizes as grown and with no further preparation. In addition, PA measurements provide also the thermal diffusivity of samples of different sizes which in this case show an increase by at least an order of magnitude than the bulk value.     

The sound generated by a square cylinder with a splitter plate at low Reynolds number

The generation of aerodynamic sound by the interaction of flow at a Reynolds number of 150 and a Mach number of 0.2 with a rigid square cylinder attached to a rigid thin flat plate is numerically investigated. When the length of the plate is varied from L=0.5D to 6D, where D is the side length of the square cylinder, the results can be grouped into three distinct regimes. For the first regime (L?D), the sound levels decrease with increasing plate length. A 3 dB sound reduction is obtained when the length of the plate is D. For the second regime (1.25D?L?4.75D), the sound levels increase with increasing plate length. For the third regime (5D?L?6D), the sound levels decrease as the length of the plate increases but the levels are higher than for the other regimes. Results also show that the lift fluctuation is the dominant sound source. These acoustic results can be explained in terms of the fluid mechanics occurring in the near wake of the cylinder.     

二环戊二烯基钛(IV)配合物的合成及表征Ⅰ——水杨酸和阿斯匹林茂钛配合物的合成及表征

选择具有抗菌、抗氧化或抗炎镇痛的药物———水杨酸（ＨＬⅠ）、阿斯匹林（ＨＬⅡ）与具有抗癌活性的二氯二茂钛（Ｃｐ２ＴｉＣｌ２）在非水介质中反应,得到两种具有潜在药理活性的茂钛配合物：Ｃｐ２Ｔｉ（ＬⅠ）２,Ｃｐ２Ｔｉ（ＬⅡ）２．经过元素分析、摩尔电导、核磁共振氢谱与碳谱、红外及紫外光谱等测试,表明水杨酸、阿斯匹林均与二氯二茂钛形成含ＴｉＯ键的单齿配位的羧酸二取代二茂钛配合物     

啤酒酵母中β-(1-3)葡聚糖的提取及其性能分析

本文采用Sevage脱蛋白法、酸溶液浸提法、碱溶液浸提法对啤酒废酵母细胞壁中的β-(1-3)葡聚糖作了提取试验,并对所获多糖进行生化特性分析,阐述了碱溶液浸提法是从啤酒酵母中回收高质量β-(1-3)葡聚糖的理想途径．     

用PCR技术检测生物硝化池污水中硝化细菌(Nitrobacteria)的研究

从生物硝化池污水水样中分离了硝化细菌ＤＮＡ,以其为模板,针对其１６ＳｒＲＮＡ基因及２３ＳｒＲＮＡ基因而设计合成了两对引物并分别进行了ＰＣＲ扩增,扩增产物的２％琼脂糖凝胶电泳结果显示,硝化细菌ＤＮＡ模板得到了特异性扩增．参照分子量标准（Ｍａｒｋｅｒ）的电泳结果,被扩增的ＤＮＡ条带大小分别约为４００ｂｐ和７３０ｂｐ．实验结果表明ＰＣＲ技术可用于污水中硝化细菌的快速检测     

Laserspektroskopie

X-Ray spectra and chemical binding     

A precision measurement of the average lifetime ofB hadrons

The average lifetime ofB hadrons was measured using data collected with the DELPHI detector at the LEP collider during 1991 and 1992. The measurement was performed using two different anayses. The first method was an improvement on a previous technique, which used charged particle impact parameter distributions. This analysis measured an average lifetime forB hadrons of

Time-resolved vibrational spectroscopy

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Time-resolved vibrational spectroscopy