Pd nanoparticles immobilized on magnetic chitosan as a novel reusable catalyst for green Heck and Suzuki cross‐coupling reaction: In water at room temperature

A novel type of magnetically responsive chitosan nanocomposite was successfully synthesized as a green and high powerful palladium‐based heterogeneous catalyst and its efficiency in Heck and Suzuki cross‐coupling was evaluated. This catalyst promote a large library of functional substrates of these reactions under mild and sustainable conditions (water or ethanol as solvent, at room temperature, in significantly short reaction time (20 minutes)) and stand as recyclable, metal scavenging catalytic systems.     

Nano-ZnO Impregnated on Starch—A Highly Efficient Heterogeneous Bio-Based Catalyst for One-Pot Synthesis of Pyranopyrimidinone and Xanthene Derivatives as Potential Antibacterial Agents

Russian Journal of Organic Chemistry - A new method has been proposed for the synthesis of pyranopyrimidinone and xanthene derivatives using zinc oxide–starch nanocomposite as catalyst under...     

Cyclotron production and parameters calculation of <Superscript>48</Superscript>V Nitinol stent for renal arteries in brachytherapy

The Nitinol stent was bombarded in a cyclotron at a flux rate of 4 μA/cm² to produce ⁴⁸V via ⁴⁸Ti (p, n) ⁴⁸V reaction. In this study dose distribution of ⁴⁸V radioactive stent was investigated for renal arteries. Version X-2.6 of the MCNP Monte Carlo radiation transport system code was employed to calculate dose distribution around the stent. As ⁴⁸V is a mixed gamma and beta particle emitter, two separate runs of MCNP for both beta and gamma particles were performed and the total deposited dose was acquired by adding the two mentioned values. In order to verify the simulation, the calculated results have been compared with previous published data for the source. Calculated results show high dose gradient near the stent and the maximum amount of dose deposits at the vessel wall. According to (AAPM) TG-60/149 protocol, the dosimetric parameters, including geometry function, G(ρ,z), radial dose function, g _L (ρ), and anisotropy function, F(ρ,z), were also determined.     

Astrophysical S-factor of the ~(12)C(α, γ)~(16)O reaction at solar energies

The astrophysical S-factor of the4He+12C radiative capture is calculated in the potential model at the energy range 0.1-2.0 MeV.Radiative capture12C(α,γ)16O is extremely relevant for the fate of massive stars and determines if the remnant of a supernova explosion becomes a black hole or a neutron star.Because this reaction occurs at low energies,the experimental measurements are very difficult and perhaps impossible.In this paper,radiative capture of the12C(α,γ)16O reaction at very low energies is taken as a case study.In comparison with other theoretical methods and available experimental data,good agreement is achieved for the astrophysical S-factor of this process.     

τ-可测算子迹的不等式

设m是具有忠实正规半有限迹τ的Hilbert空间上的一个半有限von Neumann代数.隶属于m的—个闭稠定算子x称为τ可测,如果存在常数λ≥0使得τ（e｜x｜（λ,∞））〈∞.将一些很有用的已知的Hilbert空间算子迹的不等式推广到τ-可测算子迹.特别是这些不等式蕴涵了n-元τ-可测算子的Clarkson不等式.同时还给出了τ-可测算子的广义平行四边形法则.     

Chemical separation of enriched cadmium target from copper backing in cyclotron production of radioisotope 111In

A radiochemical purification procedure was developed for the separation of enriched cadmium (¹¹¹Cd and ¹¹²Cd) from natural copper that used as backing; and was based upon the chromatographic adsorption. The separation of copper from cadmium was studied in this work. The ions were selectively separated from aqueous solution. Ion-exchange chromatography was employed as a column (1.5 cm i.d. and 15 cm length) with AG1-X8 resin (chloride form, 100–200 mesh) and a flow rate of 1–2 ml/min throughout the separation. 6 M HCl media was used for the adsorption of Cd and Cu on the resin. Then, Cu was eluted by 2 M HCl and Cd by 100 ml 0.5 M HNO₃. The amount of Cu and Cd ions in the final solution (0.5 M HNO₃) were measured by pulse polarographic method and the concentration of Cu was found to be <0.1 ppm. The Cd was quantitatively recovered and the recovery yield from ion-exchange chromatography was greater than 96 %.     

Synthesis and Characterization of Novel Poly-thiophene-nanoporous Silica and its Application for Mercury Removal from Waste Waters

In this work, MCM-41 (Mobil Composition of Matter number 41) nanoporous silica has been synthesized and characterized by X-ray powder diffraction and IR spectroscopy. In the next step, poly-thiophene was coated on the nanoporous silica in order to increase its surface area. This composite was characterized by X-Ray powder diffraction, High resolution transmission electronic microscopy micrograph (HRTEM), elemental analysis (CHNS) and Thermal analysis (TG/DTA). The application of this composite was investigated in mercury ions removal from waste water prior to determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In order to investigate the effect of nanoporous structure on the efficiency of this composite, the same composite without porous structure has been synthesized and the results were compared.     

Synthesis and Characterization of Zinc Oxide Nano-particles by Solid State Chemical Reaction Method

Several important synthetic parameters such as precursor concentration, reaction time are found to determine the growth of ZnO nanostructures. These reaction parameters can be tuned to produce a variety size of nanostructures. In this work we show the importance of these parameters on the size of synthesized zinc oxide nano-powders. ZnO nanoparticles are synthesized by the solid-state reaction using ZnSO₄·7H₂O and NaOH as the reagents. In this method Zn(OH)₂ is the intermediate product of the reaction, we show that by adjusting the molar ratio of the reagents and grinding time, we can be removed this unwanted component in the final product so for obtaining pure ZnO nanostructures the calcinations process is not necessary, also we can tune the size of ZnO nanoparticles. XRD spectra of the nanoparticles demonstrate typical diffraction peaks of a well-crystalline Wurtzite ZnO structure transmission electron microscopic observations show that these nanoparticles are of hexagonal phase ZnO mostly in round shapes and he composition analysis by EDX indicate that final product is pure ZnO. In the optimum conditions by XRD analysis we see that the mean grain size of synthesized zinc oxide nano-particles is about 44 nm.