11,055 research outputs found
Solar cells of metal-free phthalocyanine dispersed in polyvinyl carbazole. 1: Effects of the recrystallization of H2PC on cell characteristics
The development of an organic semiconductor solar cell and the effects of the recrystallization of metal free phthalocyanine (H2PC) on the characteristics of NESA/H2PC-PVK/Au sandwich cells were investigated. Alfa-H2PC sandwich cells showed photovoltage and photocurrent in a two direction opposite to that shown y as supplied H2PC cells, which consists mainly of beta-H2PC. Some difference was observed in the response times of the two cells. It is suggested that photocharacteristics change with the specific resistance of the H2PC, which is related to its crystal forms. In the cells with low resistance H2PC carriers are generated in H2PC by illumination, while in high resistance H2PC cells, carriers are generated in PVK which is sensitized with H2PC
Visibility and aerosol measurement by diode-laser random-modulation CW lidar
Examples of diode laser (DL) random-modulation continuous wave (RM-CW) lidar measurements are reported. The ability of the measurement of the visibility, vertical aerosol profile, and the cloud ceiling height is demonstrated. Although the data shown here were all measured at night time, the daytime measurement is, of course, possible. For that purpose, accurate control of the laser frequency to the center frequency of a narrow band filter is required. Now a new system with a frequency control is under construction
Method for making conductors for ferrite memory arrays
The ferrite memory arrays are made from pre-formed metal conductors for the ferrite arrays. The conductors are made by forming a thin sheet of a metallizing paste of metal alloy powder, drying the paste layer, bisque firing the dried sheet at a first temperature, and then punching the conductors from the fired sheet. During the bisque firing, the conductor sheet shrinks to 58 percent of its pre-fired volume and the alloy particles sinter together. The conductors are embedded in ferrite sheet material and finally fired at a second higher temperature during which firing the conductors shrink approximately the same degree as the ferrite material
Activation cross-sections of deuteron induced nuclear reactions on neodymium up to 50 MeV
In the frame of a systematic study of activation cross sections of deuteron
induced nuclear reactions on rare earths, the reactions on neodymium for
production of therapeutic radionuclides were measured for the first time. The
excitation functions of the natNd(d,x) 151,150,149,148m,148g,146,144,143Pm,
149,147,139mNd, 142Pr and 139gCe nuclear reactions were assessed by using the
stacked foil activation technique and high resolution $\gamma@-spectrometry.
The experimental excitation functions were compared to the theoretical
predictions calculated with the modified model codes ALICE-IPPE-D and
EMPIRE-II-D and with the data in the TENDL-2012 library based on latest version
of the TALYS code. The application of the data in the field of medical isotope
production and nuclear reaction theory is discussed
Molecular Dynamics Simulation of Sympathetic Crystallization of Molecular Ions
It is shown that the translational degrees of freedom of a large variety of
molecules, from light diatomic to heavy organic ones, can be cooled
sympathetically and brought to rest (crystallized) in a linear Paul trap. The
method relies on endowing the molecules with an appropriate positive charge,
storage in a linear radiofrequency trap, and sympathetic cooling. Two
well--known atomic coolant species, and
, are sufficient for cooling the molecular mass range
from 2 to 20,000 amu. The large molecular charge required for simultaneous
trapping of heavy molecules and of the coolant ions can easily be produced
using electrospray ionization. Crystallized molecular ions offer vast
opportunities for novel studies.Comment: Accepted for publication in Phys. Rev.
Activation cross-sections of longer lived products of deuteron induced nuclear reactions on ytterbium up to 40 MeV
In the frame of a systematic study of the activation cross-sections of the
deuteron induced nuclear reactions, excitation functions of the
natYb(d,xn)177,173,172mg,171mg,170,169Lu, natYb(d,x)175,169Yb and
natYb(d,x)173,172,168,167,165Tm reactions are studied up to 40 MeV, a few of
them for the first time. Cross-sections were measured with the activation
method using a stacked foil irradiation technique and high resolution gamma-ray
spectrometry. The experimental data are analyzed and compared to the results of
the theoretical model codes ALICE-IPPE, EMPIRE-II and TALYS. From the measured
cross-section data integral production yields were calculated. Applications of
the new cross-sections are discussed
Light-cone Gauge NSR Strings in Noncritical Dimensions II -- Ramond Sector
Light-cone gauge superstring theory in noncritical dimensions corresponds to
a worldsheet theory with nonstandard longitudinal part in the conformal gauge.
The longitudinal part of the worldsheet theory is a superconformal field theory
called X^{\pm} CFT. We show that the X^{\pm} CFT combined with the
super-reparametrization ghost system can be described by free variables. It is
possible to express the correlation functions in terms of these free variables.
Bosonizing the free variables, we construct the spin fields and BRST invariant
vertex operators for the Ramond sector in the conformal gauge formulation. By
using these vertex operators, we can rewrite the tree amplitudes of the
noncritical light-cone gauge string field theory, with external lines in the
(R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.Comment: 33 pages; v2: minor modification
Activation cross-sections of longer lived products of proton induced nuclear reactions on manganese up to 70 MeV
In the frame of a systematic study of the activation cross-sections of the
proton induced nuclear reactions, excitation functions of the
55Mn(p,x)154,152gMn,51Cr and 48V were measured up to 70 MeV. Cross-sections
were measured with the activation method using a stacked foil irradiation
technique and high resolution gamma-ray spectrometry. The experimental data are
analyzed and compared to the earlier results and to the prediction of the
EMPIRE-3 as well as the TALYS theoretical model code in the TENDL-2012 library.
From the measured cross-section data integral production yields were
calculated. Practical applications of the cross-sections are discussed
Validation of the actuator line method for simulating flow through a horizontal axis tidal stream turbine by comparison with measurements
The purpose of the present work is to evaluate the capability of the Actuator Line Method (ALM) to simulate flow through a horizontal axis tidal stream turbine. A numerical model combining the ALM with large eddy simulation technique is developed and applied to compute the flow past a laboratory-scale tidal stream turbine. The flow field is analysed in terms of streamwise mean velocity, turbulence intensity, turbulent kinetic energy and the decay rate of the maximum turbulent kinetic energy behind the turbine. It is found that the ALM performs well in predicting the mean flow and turbulence characteristics behind the turbine. The flow field predicted show a clear transition from an organised vorticity region near the turbine to a highly turbulent flow downstream. The location of this transition and the controlling parameters are discussed but further investigation, both numerical and experimental is required in order to clarify its effects on the flow structure and the performance of downstream turbines in tidal turbine arrays.Supergen Marine Challenge Programme of the EPSRC (EP/J010359/1
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