Deposition yield of nickel in alkaline bath for synthesizing Ni-63 beta source

Nickel (Ni) and Ni-63 films were synthesized by direct current electrodeposition. The composition of an alkaline electrolyte was ammonium citrate (25 g/l), hydrazine hydrate (25 g/l), and ammonium solution (25%) for adjusting the pH to 10. The acidic electrolyte at pH 4 was prepared using a full chloride bath. A higher deposition yield (92%) of the citrate electrolyte (pH 10) than 73% of acidic electrolyte (pH4) was measured using ICP. The deposition yield of radioactive Ni-63 in a citrate bath was also same as natural Ni in alkaline electrolyte. A newly prepared alkaline bath for the deposition of Ni-63 can be a solution for an extremely decreased radio-activity in the waste after plating.     

Meson production in p + d reactions

Total and differential cross sections for the reactions p + d → ³He + m ⁰ with m=π, η and p + d → ³H+π⁺ were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward-backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied. Representing the GEM Collaboration     

Measurement of optical signals as a plasma propagation in the atmospheric pressure plasma jet columns

The propagation of plasma jets with argon gas is characterized in terms of two factors, the effect of electric field distribution along the tube and the effect of voltage polarity, from the observed results of optical signals along the entire column of plasma. The optical signal of plasma propagates from the high electric-field region of high-voltage electrode toward the low field region of the open air-space, regardless of the polarity of the voltage. The optical intensity and the propagation velocity are higher for the positive voltage than for the negative voltage. Moreover, the length of plasma plume exited from the end of the glass tube into the open air is shorter for the negative voltage. When the optical intensity is strong enough, a secondary peak signal follows the primary peak. In the plasma column on the inside of the glass tube, the optical intensity and the propagation velocity depend on the strength of the electric field; they are both high at the high-field region of voltage terminal and decay toward the end of the tube. The velocity is as fast as 10⁴ m/s at the high-field region and slows down to 10³ m/s at the low-field region of the glass-tube end. However, the plasma accelerates drastically to be (10⁴–10⁵) m/s after exiting the glass tube toward open air, even though the electric field is a quite low and thus the optical signal decays low before fading out. The experimental observations present in this report are explained with the propagation of the plasma diffusion waves.     

Measurement of Reactive Hydroxyl Radical Species Inside the Biosolutions During Non-thermal Atmospheric Pressure Plasma Jet Bombardment onto the Solution

Non-thermal atmospheric pressure plasma jet could generate various kinds of radicals on biosolution surfaces as well as inside the biosolutions. The electron temperature and ion density for this non-thermal plasma jet have been measured to be about 0.8~1.0 eV and 1 × 10¹³ cm^?3 in this experiment, respectively, by atmospheric pressure collisional radiative model and ion collector current. In this context, the hydroxyl OH radical density inside the biosolutions has been also investigated experimentally by ultraviolet absorption spectroscopy when the Ar non-thermal plasma jet has been bombarded onto them. It is found that the emission and absorption profiles for the other reactive oxygen species such as NO (226 nm) and O₂*^? (245 nm) are shown to be very small inside the biosolution in comparison with those for the OH radical species. It is found that the densities of OH radical species inside the biosolutions are higher than those on the surface in this experiment. The densities of the OH radical species inside the deionized water, Dulbecco’s modified eagle medium, and phosphate buffered saline are measured to be about 2.1 × 10¹⁶, 1.1 × 10¹⁶, and 1.0 × 10¹⁶ cm^?3, respectively, at 2 mm downstream from the surface under optimized Ar gas flow of 200 sccm. It is also found that the critical hydroxyl OH radical density for the lung cancer H460 cells to experience an apoptosis is observed to be around 0.3 × 10¹⁶ cm^?3 under 1 min plasma exposure in this experiment.     

Origin of unusual work function change upon forming Tl nanoclusters on Si(111)-7x7 surface

We report an unusual behavior of the work function that remains unchanged while increasing the coverage (θ) of thallium (Tl) nanoclusters regularly arranged on a Si(111)-7×7 surface. Such a constant work function with increasing θ is understood in terms of a θ-dependent inter-cluster interaction that cancels the change induced by dipoles due to Tl nanoclusters. The spectral changes of Si 2p and Tl 5d_5/2 core-levels as a function of θ strongly indicates the presence of such an inter-clusters interaction, which is further supported by our theoretical calculation revealing a significant charge redistribution. PACS 73.20.-r; 73.30.+y; 68.47.Fg; 79.60.-i; 73.20.Hb     

Electron temperature and plasma density in surface-discharged alternating-current plasma display panels

The electron temperature and plasma density at the lateral distance of 125 /spl mu/m from the center of sustaining electrode gap have been investigated by a Langmuir probe along with the high-speed discharge image in coplanar alternating current plasma display panels. The plasma density at the lateral distance of 125 /spl mu/m from the center of sustaining electrode gap is shown to be maximum value of 3.7/spl times/10/sup 11/ cm/sup -3/, whereas the electron temperature is measured to be decreased from 1.8 to 0.8 eV as the gas pressure increases from 150 to 400 torr in this experiment. It is noted that the electron temperatures measured by the Langmuir probe and high-speed image camera are in good agreement with each other within 5% error limit.     

Synthesis and characterization of LiMnBO3 cathode material for lithium ion batteries

LiMnBO₃ with enhanced powder density was successfully synthesized by a commercially available spray-drying process. A monoclinic-LiMnBO₃ single phase was experimentally substantiated by an X-ray diffractometer with crystallinity investigated by Rietveld refinement method (Bragg R-factor and RF-factor <10). The dense LiMnBO₃ powder prepared by the spray drying process showed spherical morphology. The electrochemical property of LiMnBO₃ was extensively investigated, positively revealing that 0.27 Li⁺ (Li_0.27MnBO₃) was stoichiometrically extracted from the host LiMnBO₃ material at first cycle.     

High space harmonic perturbations in travelling wave tubes

Stability properties of the free streaming mode in an electron beam propagating through a cylindrical waveguide loaded with a tape helix are investigated, including influence of high space harmonic perturbations. Closed algebraic dispersion relation of the free streaming mode are obtained. Properties of the high space harmonic perturbations are numerically investigated in connection with application on a high frequency microwave amplifier. One of the most important features in this analysis is that instability of high harmonic perturbations occurs at a very large value of microwave frequency. In this regard, millimeter microwave can be easily attainable by reducing the helix radius to a subcentimeter.     

The onset of coulomb explosions in polyatomic molecules

With the development of high intensity femtosecond lasers, the ionisation and dissociation dynamics of molecules has become an area of considerable interest. Using the technique of femtosecond laser mass spectrometry (FLMS), the molecules carbon disulphide, pyrimidine, toluene, cyclohexanone and benzaldehyde are studied with pulse widths of 50 fs in the near infrared (IR) wavelength region (790 nm). Results are presented and contrasted for laser beam intensities around 10(15) and 10(16) W cm(-2). For the lower intensities, the mass spectra yield dominant singly charged parent ions. Additionally, the appearance of doubly charged parent ions is evident for carbon disulphide, toluene and benzaldehyde with envelopes of doubly charged satellite species existing in these local regions. Carbon disulphide also reveals a small triply charged component. Such atomic-like features are thought to be a strong fingerprint of FLMS at these intensities. However, upon increasing the laser intensity to approximately 10(16) W cm(-2), parent ion dominance decreases and the appearance of multiply charged atomic species occurs, particularly carbon. This phenomenon has been attributed to Coulomb explosions in which the fast absorption of many photons may produce transient highly ionised parent species which can subsequently blow apart. Copyright 1999 John Wiley & Sons, Ltd.     

Generalization of Wilemski-Fixman-Weiss decoupling approximation to the case involving multiple sinks of different sizes, shapes, and reactivities

We generalize the Wilemski-Fixman-Weiss decoupling approximation to calculate the transient rate of absorption of point particles into multiple sinks of different sizes, shapes, and reactivities. As an application we consider the case involving two spherical sinks. We obtain a Laplace-transform expression for the transient rate that is in excellent agreement with computer simulations. The long-time steady-state rate has a relatively simple expression, which clearly shows the dependence on the diffusion constant of the particles and on the sizes and reactivities of sinks, and its numerical result is in good agreement with the known exact result that is given in terms of recursion relations.