A rigorous control of logarithmic corrections in four-dimensional ϕ4 spin systems

Using Gawedzki and Kupiainen's rigorous block spin transformation method, we study critical phenomena in ⁴ spin systems in four dimensions. In Part I of this work we investigate in detail the renormalization group trajectory of the system not exactly at the critical point.     

Short-range part of the NN interaction: Lowest-order relativistic corrections to equivalent local potentials from quark exchange kernels

The full Breit hamiltonian, including the Darwin term and relativistic kinetic-energy correction, has been used to construct resonating group kernels in analytic form for the six-quark NN system. The nonlocal kernels have been converted to equivalent local potentials using the WKB approximation based on their Wigner transforms. The equivalent local potentials have been confirmed to be rather insensitive to a choice of parameters and to be fairly accurate by comparing with the phase shifts and the wave functions obtained with the RGM equation. The results indicate the importance of the Darwin term. The term leads to a large reduction of the strong repulsive cores given by the color magnetic interaction and makes the resulting potentials less repulsive than those which neglect this term. The relative importance of the various components in the Breit interaction and of the quark-gluon exchange diagrams is made clear.     

水斗非定常自由水膜流三维贴体数值模拟

本研究采用水斗三维非正交贴体坐标系进行了非定常自由水膜流动的数值解析。对不规则水斗内表面采用三维非正交贴体坐标系下离散点进行拟合,推导了曲面离散点的法向矢量和曲面微元面高斯曲率、平均曲率等几何特征量的计算公式,进而导出流体粒子在运动方向上曲率计算式。在水斗三维贴体坐标系中,还推导了流体粒子在水斗曲面上的运动控制方程。最后对某水轮机水斗内表面非定常自由水膜流进行了数值模拟,得到其非定常水膜流态分布。     

Multiwalled carbon nanotubes mass-produced by dc arc discharge in He–H2 gas mixture

Uniform cathode deposits (longer than 15 mm), containing multiwalled carbon nanotubes (MWNTs) inside, were produced by dc arc discharge evaporation with a computer-controlled feeder of a pure-carbon electrode without a metal catalyst in a He–H₂ gas mixture. The purification of MWNTs was carried out to remove amorphous carbon and carbon nanoparticles. High-resolution transmission electron microscopy observations and Raman scattering studies show that the MWNTs possess a high crystallinity and a mean outermost diameter of ∼ ∼10 nm. It has been confirmed that the current density in the electron field emission from a purified MWNT mat can reach 77.92 mA/cm², indicating that the purified MWNTs are a promising candidate electron source in a super high-luminance light-source tube or a miniature X-ray source.     

WIDE RANGE DETECTOR USING PARABOLIC CYLINDRICAL MIRROR FOR THz APPLICATIONS

A new, wide-band, high-speed and high-sensitivity THz detector has been developed. The prototype detector consists of a parabolic cylindrical mirror, a long wire antenna and a Schottky barrier diode. Direct detection measurements have shown a stable sensitivity of 150 ± 50 V/W for 1–2 THz without any adjustments. The long wire antenna was fixed at the focus of parabolic cylindrical mirror then it has been realized less operation steps, easy coupling to the external THz signals and a dramatic enhancement in the practicality of this system. The optically polished mirror and frosted surface one showed comparable sensitivities, thus easy polishing and less cost mirror fabrication can be applied for this system. The radiation pattern showed a maximum radiation angle of approximately 23° with its dominant main lobe, which was attributed to the wire antenna character and confirmed good agreements with classical antenna theory.     

A Genus-3 Topological Recursion Relation

In this paper, we give a new genus-3 topological recursion relation for Gromov-Witten invariants of compact symplectic manifolds. This formula also applies to intersection numbers on moduli spaces of spin curves. A by-product of the proof of this formula is a new relation in the tautological ring of the moduli space of 1-pointed genus-3 stable curves. Research of the first author was partially supported by NSF grant DMS-0204824 Research of the second author was partially supported by NSF grant DMS-0505835     

High intensity focused ultrasound-induced gene activation in solid tumors

In this work, the activation of heat-sensitive trans-gene by high-intensity focused ultrasound (HIFU) in a tumor model was investigated. 4T1 cancer cells (2 x 10(6)) were inoculated subcutaneously in the hind limbs of Balb/C mice. The tumors were subsequently transducted on day 10 by intratumoral injection of a heat-sensitive adenovirus vector (Adeno-hsp70B-Luc at 2 x 10(8) pfu/tumor). On day 11, the tumors were heated to a peak temperature of 55, 65, 75, or 85 degrees C within 10-30 s at multiple sites around the center of the tumor by a 1.1- or 3.3-MHz HIFU transducer. Inducible luciferase gene expression was increased from 15-fold to 120-fold of the control group following 1.1-MHz HIFU exposure. Maximum gene activation (120-fold) was produced at a peak temperature of 65-75 degrees C one day following HIFU exposure and decayed to baseline within 7 days. HIFU-induced gene activation (75 degrees C-10 s) could be further improved by using a 3.3-MHz transducer and a dense scan strategy to 170-fold. Thermal stress, rather than nonthermal mechanical stress, was identified as the primary physical mechanism for HIFU-induced gene activation in vivo. Overall, these observations open up the possibility for combining HIFU thermal ablation with heat-regulated gene therapy for cancer treatment.     

Synthesis of Al–Cr decagonal quasicrystal nanoparticles and their temperature of phase transformation to stable crystal phase

The synthesis of Al–Cr single quasicrystal (QC) nanoparticles of the decagonal phase was achieved by introducing an advanced gas flow evaporation method. By obtaining successive electron diffraction patterns for single-QC nanoparticles, the phase transformation temperature of a single-QC nanoparticle was determined to be 700 °C. It was also determined that part of the QC nanoparticle decomposed into hex-Al₈Cr₅ and Al during the phase transformation. Since the grain growth did not occur during the phase transformation in the present experiment, the inherent phase transformation temperature could be measured.     

Simultaneous observation of CO isotopomer absorption by broadband difference-frequency generation using a direct-bonded quasi-phase-matched LiNbO3 waveguide

Rovibration absorption lines both of 12CO and 13CO are observed simultaneously with the output of a 2 microm broadband difference frequency generated in a direct-bonded quasi-phase-matched LiNbO3 waveguide, which is a 50 mm device with a single quasi-phase-matching period that is operated at a constant temperature. The wavelength conversion efficiency and the difference-frequency generation bandwidth reach 100%/W and 100 nm, respectively. The idler output bandwidth in the 2 microm region is obtained by group-velocity matching or phase-mismatch minimization when a 0.94 microm pump laser diode and a 1.55 microm tunable signal source are used.