Design of a 2.4 GHz High-Performance Up-Conversion Mixer with Current Mirror Topology

In this paper, a low voltage low power up-conversion mixer, designed in a Chartered 0.18 μm RFCMOS technology, is proposed to realize the transmitter front-end in the frequency band of 2.4 GHz. The up-conversion mixer uses the current mirror topology and current-bleeding technique in both the driver and switching stages with a simple degeneration resistor. The proposed mixer converts an input of 100 MHz intermediate frequency (IF) signal to an output of 2.4 GHz radio frequency (RF) signal, with a local oscillator (LO) power of 2 dBm at 2.3 GHz. A comparison with conventional CMOS up-conversion mixer shows that this mixer has advantages of low voltage, low power consumption and high-performance. The post-layout simulation results demonstrate that at 2.4 GHz, the circuit has a conversion gain of 7.1 dB, an input-referred third-order intercept point (IIP3) of 7.3 dBm and a noise figure of 11.9 dB, while drawing only 3.8 mA for the mixer core under a supply voltage of 1.2 V. The chip area including testing pads is only 0.62×0.65 mm2

Theory of high energy features in angle-resolved photo-emission spectra of hole-doped cuprates

The recent angle-resolved photoemission measurements performed up to binding energies of the order of 1eV reveals a very robust feature: the nodal quasi-particle dispersion breaks up around 0.3-0.4eV and reappears around 0.6-0.8eV. The intensity map in the energy-momentum space shows a waterfall like feature between these two energy scales. We argue and numerically demonstrate that these experimental features follow naturally from the strong correlation effects built in the familiar t-J model, and reflect the connection between the fermi level and the lower Hubbard band. The results were obtained by a mean field theory that effectively projects electrons by quantum interference between two bands of fermions instead of binding slave particles.Comment: 5 pages 2 fig

Novel method for refinement of retained austenite in micro/nano-structured bainitic steels

A comparative study was conducted to assess the effects of two different heat treatments on the amount and morphology of the retained austenite in a micro/nano-structured bainitic steel. The heat treatments used in this work were two-stage bainitic transformation and bainitic-partitioning transformation. Both methods resulted in the generation of a multi-phase microstructure containing nanoscale bainitic ferrite, and/or fresh martensitic phases and much finer retained austenite. Both heat treatments were verified to be effective in refining the retained austenite in micro/nano-structured bainite and increasing the hardness. However, the bainitic transformation followed by partitioning cycle was proved to be a more viable approach than the two-stage bainitic transformation due to much shorter processing time, i.e. ∼2 h compared to ∼4 day, respectively

Universality and properties of neutron star type I critical collapses

We study the neutron star axisymmetric critical solution previously found in the numerical studies of neutron star mergers. Using neutron star-like initial data and performing similar merger simulations, we demonstrate that the solution is indeed a semi-attractor on the threshold plane separating the basin of a neutron star and the basin of a black hole in the solution space of the Einstein equations. In order to explore the extent of the attraction basin of the neutron star semiattractor, we construct initial data phase spaces for these neutron star-like initial data. From these phase spaces, we also observe several interesting dynamical scenarios where the merged object is supported from prompt collapse. The properties of the critical index of the solution, in particular, its dependence on conserved quantities, are then studied. From the study, it is found that a family of neutron star semi-attractors exist that can be classified by both their rest masses and ADM masses.Comment: 13 pages, 12 figures, 1 new reference adde

Calculated Momentum Dependence of Zhang-Rice States in Transition Metal Oxides

Using a combination of local density functional theory and cluster exact diagonalization based dynamical mean field theory, we calculate many body electronic structures of several Mott insulating oxides including undoped high T_{c} materials. The dispersions of the lowest occupied electronic states are associated with the Zhang-Rice singlets in cuprates and with doublets, triplets, quadruplets and quintets in more general cases. Our results agree with angle resolved photoemission experiments including the decrease of the spectral weight of the Zhang--Rice band as it approaches k=0

Studies of Colletotrichum dematium f. sp. truncatum on soybean

Growth and sporulation studies of Colletotrichum dematium var. truncatum were conducted using different media, temperatures and light regimes. Of the seven media employed oat meal agar supported the best mycelial growth, with sporulation best on Czapek Dox agar and potato dextrose agar. Greater mycelial growth was obtained under 12 hours alternating ultraviolet light and continuous light than in darkness. Sporulation was highest under 12 hours alternating light treatment. The optimum temperature for growth and sporulation was 25° C while germination was optimum at 20° C. Pathogenicity studies in the glasshouse showed that seedlings of cultivar 66D-16 were most susceptible while cultivar 66F-4A most resistant. Inoculation studies on detached green pods indicated that 66D-16 was most susceptible and Palmetto most resistant. An in vitro efficacy test of five fungicides against the fungus showed that Topsin M was the most toxic with an EDso of 2.2 pgjml