Fabrication of blue LEDs on big chips

In this paper, the GaN based epitaxial wafer is fabricated on big 1 mmx1 mm chips, and packaged with a special technology. At working current 350 mA and working voltage 3.74 V, the full viewing angle, the axial brightness and the output integral power of the 465 nm LED can reach 125? 210, 000 cd/m2 and 1.5 1m, respectively. The LED with such good performances has promising application potential in the fields of display, traffic and the development of solid-state white light source.     

How quantum is the big bang?

When quantum gravity is used to discuss the big bang singularity, the most important, though rarely addressed, question is what role genuine quantum degrees of freedom play. Here, complete effective equations are derived for isotropic models with an interacting scalar to all orders in the expansions involved. The resulting coupling terms show that quantum fluctuations do not affect the bounce much. Quantum correlations, however, do have an important role and could even eliminate the bounce. How quantum gravity regularizes the big bang depends crucially on properties of the quantum state.     

How big is the universe today?

If one defines the size of the present universe in terms of a hypersurface of simultaneity generated by the spatial geodesies orthogonal to our world line today, then it is finite in all expanding Big Bang Friedmann models.     

Biochemistry and semiconductor electronics--the next big hit for silicon?

Two recent developments portend a new era for silicon electronics in biomedical applications. Firstly, highly specific chemical recognition and massively parallel sample preparation techniques are being combined with VLSI to make new kinds of analytical chips. Secondly, critical dimensions are beginning to approach the size of biomolecules, opening new pathways for physical interactions between molecules and semiconductor structures. Future generations of hybrid chemical-CMOS devices could revolutionize diagnosis and make personalized medicine cheap enough to become widespread.     

How fast can cracks move? A research adventure in materials failure using millions of atoms and big computers

During the last decade, we have been simulating the dynamic failure of brittle and ductile solids at the atomic level using some of the world's fastest computers. Computer experiments encompassing crack dynamics in brittle fracture, crack blunting in ductile failure, and multi-dislocation entanglement in work-hardening are some examples and have given new and exciting insights into the failure processes of solids. Our presentation begins at an introduction level where basic concepts are presented before their application is needed for the understanding of specific phenomena. The story is primarily based on our past experiences, and our goal is to give the reader a fundamental appreciation for how materials fail.     

Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in China

A big earthquake (Ms = 8.1) occurred at western Kunlun Mts gap on November 14, 2001. It is the biggest earthquake in China in the past 50 years and the only one with a magnitude bigger than 8 in China after Dangxiong Earthquake (M = 8) in Tibet in 1951. The big earthquake has drawn wide attention of scientists in seismological, geophysical, geological and astro-geodynamic circles. Scientists are interested in the occurrence regularity of the very big earthquakes and try to find out the fac…     

Key resonant states in the8Li(α,n)11B reaction in the inhomogeneous big bang models

The resonant states in the key reaction⁸Li(,n)¹¹B for the inhomogeneous Big Bang Models were studied experimentally through the⁹Be(,p)¹²B reaction at 64 MeV. This reaction is found to excite all the resonances of interest in¹²B. The most crucial resonant state at 10.572 MeV in¹²B (0.572 MeV above the threshold) was found to have _tot20±10 keV and J=(1^–), suggesting that the S-factor of the (,n) process should be larger than that obtained before.     

Determination of δ13 CV−PDB and δ15NAIR values of cocaine from a big seizure in Germany by stable isotope ratio mass spectrometry†

In this study, δ¹³C_{V? PDB} and δ¹⁵N_AIR values of 132 cocaine samples from a big seizure in Germany in 2002 were determined using elemental analyser isotope ratio mass spectrometry. The 1.2 tons of cocaine were packed in 1 kg packages and the cocaine bricks inside these packages showed certain logos. Twenty different logos could be identified. Results show a large variability among some samples, for δ¹⁵N_AIR values ranging from?17 to ?2 ‰. Furthermore, the possibility of linking samples with the same logo was checked. The results show that, in general, there is no relationship between the determined isotope ratio and a certain logo.     

Towards large volume big divisor D3/D7 “μ-split supersymmetry” and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

We show that it is possible to realize a “μ-split SUSY” scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the “big” divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for ΣB obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson?s algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.     

The big bang as a result of the first-order phase transition driven by a change of the scalar curvature in an expanding early Universe: The “hyperinflation” scenario

We suggest that the Big Bang could be a result of the first-order phase transition driven by a change in the scalar curvature of the 4D spacetime in an expanding cold Universe filled with a nonlinear scalar field φ and neutral matter with an equation of state p = νε (where p and ε are the pressure and energy density of the matter, respectively). We consider the Lagrangian of a scalar field with nonlinearity φ⁴ in a curved spacetime that, along with the term–ξR|φ|² quadratic in φ (where ξ is the interaction constant between the scalar and gravitational fields and R is the scalar curvature), contains the term ξRφ₀(φ + φ⁺) linear in φ, where φ₀ is the vacuum mean of the scalar field amplitude. As a consequence, the condition for the existence of extrema of the scalar-field potential energy is reduced to an equation cubic in φ. Provided that ν > 1/3, the scalar curvature R = [κ(3ν–1)ε–4Λ] (where κ and Λ are Einstein’s gravitational and cosmological constants, respectively) decreases with decreasing ε as the Universe expands, and a first-order phase transition in variable “external field” parameter proportional to R occurs at some critical value R _c < 0. Under certain conditions, the critical radius of the early Universe at the point of the first-order phase transition can reach an arbitrary large value, so that this scenario of unrestricted “inflation” of the Universe may be called “hyperinflation.” After the passage through the phase-transition point, the scalar-field potential energy should be rapidly released, which must lead to strong heating of the Universe, playing the role of the Big Bang.     

Possible triggering of solar activity to big earthquakes (<Emphasis Type="Italic">Ms</Emphasis>≥8) in faults with near west-east strike in China

This paper studies the relationship between solar activity and big earthquakes (Ms≥8) that occurred in China and western Mongolia. It is discovered that the occurrence dates of most of the big earthquakes in and near faults with west-east strike are close to the maximum years of sunspot numbers, whereas dates of some big earthquakes which are not in such faults are not close to the maximum years. We consider that it is possibly because of the appearance of many magnetic storms in the maximum years of solar activity. The magnetic storms result in anomalies of geomagnetic field and then produce eddy current in the faults gestating earthquake with near west-east strike. Perhaps the gestated big earthquakes occur easily since the eddy current heats the rocks in the faults and therefore decreases the shear resistant intensity and the static friction limit of the rocks.