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[en] The behavior of disordered isolated volumes (zones) in InP under electron action was characterized by TEM observations. The total areal fraction of the disordered zones in initial InP pre-irradiated by 100 keV heavy Au ions decreased as a function of irradiating electron fluence (time of TEM electron beam irradiation) within all the investigated electron energy range (100–300 keV), Disappearance of disordered zones shows that these zones are sensitive to electron beam irradiation and recover even under electron energies not sufficient to directly elastically displace lattice atoms In and P.
[en] The present work extends the previous work on 5-ion system to consider 7-ion system (i.e., Au47+∼Au53+). It is found that more highly charged ions, e.g., Au53+, Au54+ etc., could be able to be neglected, however, less highly charged ions, e.g., Au47+, Au46+ etc., are rather important. Therefore, a new idea to consider 8-ion system, i.e., Au46+∼Au53+, is under way. As a supplement, we discuss the simultaneous reaction, which would be important in this sort of works.
[en] In the present study, gold nanoparticles (GNPs) were prepared at boiling temperature (90-95 degree C) by treating gold ions with Citrus fruit extracts. The effect of mixing ratios of the reactants and concentration of gold hydrochloride was studied. In the standardization process, 10/sup -3/ M solution of HAuCl/sub 4/.3H/sub 2/O was reacted with fruit extracts for half an hour at 90-95 degree C in different ratios. GNPs were characterized by UV-Vis spectroscopy (UV-Vis) and atomic force microscopy (AFM). Their stability was evaluated against varying pH solutions and volumes of sodium chloride along with metals and antibiotics sensing ability. The gold nanoparticles were tested for antibacterial and antifungal activities against various pathogenic strains. The UV-Vis spectra of gold nanoparticles gave surface plasmon resonance at about 540 nm while the AFM images revealed the particle size within the range of 70-100 nm. GNPs showed remarkable stability in varying pH solutions and salt volumes as well as high detection ability towards cobalt, copper, ceftriaxone and penicillin. Moreover, the GNPs possessed moderate antibacterial and good antifungal activity. These results concluded that the Citrus fruit extracts can be utilized for large scale synthesis of cost-effective nanoparticles which may have compatibility for biomedical and pharmaceutical applications. (author)
[en] Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter
[en] The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is beginning its second year of operation. A cesium sputter ion source injecting into a tandem Van de Graaff provides the gold ions for RHIC. The ion source is operated in the pulsed beam mode and produces a 500microsec long pulse of Au- with a peak intensity of 290pA at the entrance of the tandem. After acceleration in the tandem and post stripping, this results in a beam of Au+32 with an intensity of 80emicro
[en] A Gold ion with charge eQ has N = 197 Nucleons, Z = 79 Protons, and (Z-Q) electrons. (Here Q is an integer and e is the charge of a single proton.) The mass is m = au - Qme + Eb/c2 (1) where a = 196.966552 is the relative atomic mass (1, 2) of the neutral Gold atom, u = 931.494013 MeV/c2 is the unified atomic mass unit (3), and mec2 = .510998902 MeV is the electron mass (3). Eb is the binding energy of the Q electrons removed from the neutral Gold atom. This amounts to 0.332 MeV for the helium-like gold ion (Q = 77) and 0.517 MeV for the fully stripped ion. For the Au31+ ion we have Eb = 13.5 keV. These numbers are given in Ref. (4).
[en] Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Many issues, regarding a low energy high current electron beam that is needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, were examined. Computations and some experimental data indicate that none of these issues is a show stopper. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in about one meter. Hence, this option cooling deserves further more serious considerations.
[en] The results of a numerical simulation of Au ion-beam transportation from an ESIS source to the beginning of the linear accelerator (radio frequency quadrupole (RFQ)) are given. Features of two versions of the channel (without separation and with a separation of charges) are analyzed.
[en] Highlights: • Graphene oxide interface enhances the rate of photochemical reduction of gold ions in water. • The size, shape and morphology of the Au nanocrystals assembled on the RGO nanosheets are controlled by the photochemical reduction process. • Enhanced photothermal energy conversion from the [email protected] nanocomposites is observed. • The [email protected] nanocomposites are promising materials for photothermal therapy and for the efficient conversion of solar energy into usable heat for a variety of applications. A novel photochemical approach is presented for the synthesis of shape-controlled plasmonic gold nanostructures supported on reduced graphene oxide. Graphene oxide (GO) interface enhances the rate of photochemical reduction of gold ions in water and influnces the growth rate of the initial gold nuclei leading the the formation of different shapes and assembiles depeding on the light source. The size, shape and morphology of the Au nanocrystals could be tailored by varying the light source and the exposure time. The resulting hybrid [email protected] plasmonic nanostructures show signficantly enhanced photostability and photothermal response as compared to free gold nanostructures.