The influence of solar radiations to the physical and structural properties of CR-39

Long chain polymers owe many of their properties to the structural arrangements of their molecules and are extensively used for many industrial and applied sciences. One of such application is their perspective use in the field of solid-state nuclear track detectors. However they are profoundly influenced by low LET radiations exposure and new structural arrangements may emerge. CR-39 is one of the most popular polymeric track detectors, however its aliphatic nature restricts its applications. Thus in the present investigations the damage densities produced by solar radiations to the polymer have been estimated by analyzing the structural, physical and etching properties of the polymer. The polymer is found to be highly sensitive towards solar radiations and great changes in physical and structural properties of polymer have been observed. The sensitivity of the polymer has been found to decrease by 83.40% during eight months.      

Surface-functionalized nanoparticles with liquid-like behavior: The role of the constituent components

Ionically modified silica nanoparticles with large counter anions (sulfonate, isostearate) at two silica volume fractions (13 and 27%) form a viscous fluid and a glass but not crystalline solids. Dielectric spectroscopy, Brillouin scattering and shear rheometry were employed to investigate these new nanoparticle-based fluids. The glass transition temperature and hence the local dynamics are governed by the large counter anions, whereas the flow properties can be controlled by the spatial correlation between the nanoparticles, e.g. by tuning the volume fraction of hard cores and local interactions between segments in the soft corona. Liquid-like ordering of the cores was revealed by X-ray scattering and found to influence significantly the macroscopic flow properties of these salts.     

Accurate ball tracking in volleyball actions to support referees

This paper proposes a method for offline accurate ball tracking for short volleyball actions in sport halls. Our aim is to detect block touches on the ball and to determinate accurate trajectory and impact positions of the ball to support referees. The proposed method is divided into two stages, namely training and ball tracking, and is based on background subtraction. Application of the Gaussian mixture model has been used to estimate a background, and a high-speed camera with a capture rate of 180 frames per second and a resolution of 1920?×?1080 are used for motion capture. In sport halls significant differences in light intensity occur between each sequence frame. To minimize the influence of these light changes, an additional model is created and template matching is used for accurate determination of ball positions when the ball contour in the foreground image is distorted. We show that this algorithm is more accurate than other methods used in similar systems. Our light intensity change model eliminates almost all pixels added to images of moving objects owing to sudden changes in intensity. The average accuracy achieved in the validation process is of 0.57 pixel. Our algorithm accurately determined 99.8% of all ball positions from 2000 test frames, with 25.4?ms being the average time for a single frame analysis. The algorithm presented in this paper is the first stage of referee support using a system of many cameras and 3D trajectories.     

The Br,Fe, Rb,Sr, and Zn contents and interrelation in intact and morphologic normal prostate tissue of adult men investigated by energy‐dispersive X‐ray fluorescent analysis

A method for radionuclide‐induced (¹⁰⁹Cd) energy‐dispersive X‐ray fluorescent (EDXRF) was used to determine Br, Fe, Rb, Sr, and Zn contents in intact and morphologic normal prostate tissues. Prostates were removed at necropsy from 64 men (mean age 36.5 years, range 13–60) who had died suddenly. All materials were divided into two parts. One part was morphologically examined, whereas chemical element contents of the other were estimated. Mean values (M ± SΕΜ) for mass fraction of Br, Fe, Rb, Sr, and Zn (mg kg^?1 on dry‐weight basis) in the intact and morphologic normal prostate tissue were 35.5 ± 4.0, 107 ± 5.4, 17.1 ± 0.8, 1.9 ± 0.3, and 850 ± 79, respectively. Mean values (M ± SΕΜ) for Zn/Fe, Zn/Rb, and Zn/Sr ratios of mass fraction were 8.72 ± 0.80, 57.4 ± 7.2, and 567 ± 82, respectively. A strongly pronounced tendency of age‐related exponential increase in Zn mass fraction as well an increase in Zn/Fe, Zn/Rb, and Zn/Sr ratios in prostate was observed. A significant positive correlation was seen between the prostatic zinc and iron contents (p ≤ 0.05, r = 0.22) and between the prostatic zinc and bromine contents (p ≤ 0.01, r = 0.43). Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of Gas Environment on Metal-Support Interactions of Supported Metal Catalysts

Supported-metal catalysts, pivotal for industrial applications, have their catalytic properties affected by metal-support interactions (MSIs), which notably influence both their electronic and geometric characteristics. Therefore, understanding internal and external factors that influence MSIs is crucial for the rational design of catalysts. Our minireview focuses on the effects of the gas environment on the MSIs, particularly the morphological changes in metal nanoparticles, the migrating behavior of reducible supports (strong metal-support interaction), and the compositional rearrangement of the catalysts (reactive metal-support interaction). Future directions are suggested to elucidate the fundamental aspects of gas environment induced structural reconstruction of catalysts, including the quantitative analysis of dynamic behavior of both the surface and interface, atomic-level insights into the structures of the metal, support, and interface under pertinent conditions through advanced in situ/operando characterization, and the in situ manipulation of structural reconstruction.     

分光仪调整中干涉现象的分析与应用

描述了在分光仪调整实验中观察到的干涉条纹现象,并且当转动平行平板玻璃时,该干涉条纹有粗细疏密变化.本文从理论上分析了产生干涉条纹及干涉条纹疏密粗细变化的原因.在已知平行平板玻璃的厚度和光的波长的情况下,可应用该现象测量平行平板玻璃折射率,给出了折射率的计算方法,对结果进行了数据处理及误差分析.     

Structural changes in thermal-induced polyacrylonitrile gel under uniaxial drawing

The influences of uniaxial drawing on the different structural scales in thermal-induced polyacrylonitrile (PAN) gel were studied. The results of atomic force microscopy (AFM) and swelling tests indicated that the drawn PAN gels had more compact structure with less solvent contained. Besides, some microphase separations occurred in the highly drawn gel and caused the gel to become more porous, as verified by the results from differential scanning calorimetry (DSC). The wide-angle X-ray diffraction (WAXD) results confirmed that drawing induces chain orientation and partial crystallization in the thermal-induced PAN gels, and higher draw ratio generated greater structural changes in the gels. It was also found from the tensile stress relaxation of the gels that the crosslinks in the gel increased with the draw ratio. In Fourier transform infrared (FTIR) spectra, the blue shift in wave numbers of two absorption peaks (3200-3700 cm⁻¹ and around 2244 cm⁻¹), and a gradually disappearing peak at 1036 cm⁻¹ all indicated the weakening hydrogen bonding between the PAN molecular chains and dimethyl sulfoxide (DMSO) molecules during the drawing process.     

Binding of naproxen to bovine serum albumin and tryptophan-modified bovine serum albumin

Two classes of binding sites, a single high-affinity site with an association constant of 4·8×10⁶ M⁻¹ and two low-affinity sites with association constant of about 0·05×10⁶ M⁻¹ have been observed in the interaction of Naproxen with bovine serum albumin (BSA). Chemical modification of two tryptophan residues in BSA with 2-hydroxy-5-nitrobenzyl bromide has led to a reduction in the association constant of the high-affinity site by 89% and its number of binding sites by 66% suggesting the involvement of tryptophan residues in the high-affinity site. In contrast, the two low-affinity sites were not affected by the modification. Binding of Naproxen to the low-affinity sites of BSA induces microdisorganisation of the albumin structure leading to conformational changes as evident from fluorescence measurements with 1-anilino-8-naphthalenesulphonic acid as the probe.     

Volume and compressibility effects in the formation of metal-EDTA complexes

We used precise measurements of ultrasonic velocity and density to study the complexation of ethylendiaminetetraacetic acid (EDTA) with Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺ at 25‡C and pH 12. From these measurements we obtained the changes in the molar concentration increment of the ultrasonic velocity δA, the apparent molar adiabatic compressibility δK_sΦ, and the apparent molar volume δV_Φ of complex formation. The hydration contributions δ(AV_h) to the volume effect of binding range from 39.6 to 46.6 cm³-mol^-1 while the hydration contribution to the adiabatic compressibility change in the binding, δ(δK_h), ranges from 103.9X 10^-4 to 131.1 X 10^-4 cm³-mol^-1-bar^-1. These data are interpreted in terms of dehydration of interacting molecules,i.e., transfer of water molecules from the hydration shells of cations and EDTA into the bulk water. The ratio δ(δV_h)/ δ(δV_h) is in the range 0.35 to 0.38 bar, indicating a dominant contribution from the dehydration of charged atomic groups in the volume and the compressibility effects of complex formation.