The ordinary quiver of a weight three block of the symmetric group is bipartite

Suppose F is a field of characteristic p?5, and that B is a p-block of the symmetric group Sn of defect 3. We prove that the Ext¹-quiver of B is bipartite, with the bipartition being described in a simple way using the leg-lengths of p-hooks of partitions.     

算子值酉随机矩阵及其渐近自由性

该文在算子值非交换概率空间上引入半标准酉随机矩阵的概念, 证明了它是算子值Haar酉元的矩阵模型,并给出了半标准酉随机矩阵的渐近自由判定定理.     

New algebraic structures from Hermitian one-matrix model

Virasoro constraint is the operator algebra version of one-loop equation for a Hermitian one-matrix model, and it plays an important role in solving the model. We construct the realization of the Virasoro constraint from the Conformal Field Theory (CFT) method. From multi-loop equations of the one-matrix model, we get a more general constraint. It can be expressed in terms of the operator algebras, which is the Virasoro subalgebra with extra parameters. In this sense, we named as generalized Virasoro constraint. We enlarge this algebra with central extension, this is a new kind of algebra, and the usual Virasoro algebra is its subalgebra. And we give a bosonic realization of its subalgebra.     

不可微规划的极大熵不动点算法

本文将极大熵逼近方法和不动点计算方法有机地结合,提出了一种不可微规划计算方法．该方法同样也适用于求解可微规划,而后给出了该方法的收敛性     

Combinatorial coverings from geometries over principal ideal rings

A t-(v, k, λ) covering is an incidence structure with v points, each block incident on exactly k points, such that every set of t distinct points is incident on at least λ blocks. By considering certain geometries over finite principal ideal rings, we construct infinite families of t-(v, k, λ) coverings having many interesting combinatorial properties. © 1999 John & Sons, Inc. J Combin Designs 7: 247–268, 1999     

RTP协议中RTCP传输间隔算法

针对应用RTP的大规模会话，提出了改进的RTCP传输间隔算法，并对改进算法和现行算法进行了模拟和分析，结果表明改进算法有效地减小了因大量用户同时加入而导致的RTCP包发送间隔误差，缓解了大规模会话初始时RTCP包造成的拥塞．     

Boundary layer viscosity of CNT-doped liquid crystals: effects of phase behavior

Carbon nanotube (CNT)-doped liquid crystals (LCs) have attracted intensive research studies as prospective materials in optic display devices, microfluidic sensors, and lubricants due to their unique molecular structures and properties. In this paper, the interaction between the doped CNTs and the hosting 4-cyano-4 $^{\prime }$ -pentylbiphenyl (5CB) molecules (in both nematic and isotropic phases) was investigated and we focused on the boundary layer rheological properties of the CNT-doped 5CB under external electric field. The experiments were performed by using a quartz crystal microbalance (for boundary layer viscosity investigation) and a rheometer (for bulk viscosity measurement). The results indicate that the bulk viscosity of the CNT-doped 5CB presents an obvious electroviscous effect in its nematic phase while no electroviscous effect in its isotropic phase. Additionally, we found that the boundary layer viscosity of the CNT-doped 5CB demonstrated significant electroviscous effects both in its nematic phase and isotropic phase. The enhanced electroviscous effects on the boundary layer viscosity of CNT-doped 5CB can be attributed to the highly ordered structures of LC molecules and CNTs on the substrate under external electric field. The unique properties of the boundary layer rheology of CNT-doped 5CB LC were further discussed in view of the ordering of LC molecules induced by the electric field, the polarity of CNTs, and the aligning interaction between CNTs and LC molecules.     

Concentration of nitrogen molecules needed by nitrogen nanobubbles existing in bulk water

This paper investigates the stability of nitrogen nanobubbles under dif~ ferent concentrations of nitrogen molecules by molecular dynamics simulations. It is found that the stability of nanobubbles is very sensitive to the concentration of nitrogen molecules in water. A sharp transition between disperse states and assemble states of nitrogen molecules is observed when the concentration of nitrogen molecules is changed. The relevant critical concentration of nitrogen molecules needed by the existing nitrogen nanobubbles is analyzed.     

Evolution of planetary boundary layer under different weather conditions,and its impact on aerosol concentrations

A field experiment was conducted in Tianjin,China from September 9-30,2010,focused on the evolution of Planetary Boundary Layer（PBL） and its impact on surface air pollutants.The experiment used three remote sensing instruments,wind profile radar（WPR）,microwave radiometer（MWR） and micro-pulse lidar（MPL）,to detect the vertical profiles of winds,temperature,and aerosol backscattering coefficient and to measure the vertical profiles of surface pollutants（aerosol,CO,SO₂,NO_x）,and also collected sonic anemometers data from a 255-m meteorological tower.Based on these measurements,the evolution of the PBL was estimated.The averaged PBL height was about 1000-1300 m during noon/afternoon-time, and 200-300 m during night-time.The PBL height and the aerosol concentrations were anti-correlated during clear and haze conditions.The averaged maximum PBL heights were 1.08 and 1.70 km while the averaged aerosol concentrations were 52 and 17μg/m³ under haze and clear sky conditions,respectively. The influence of aerosols and clouds on solar radiation was observed based on sonic anemometers data collected from the 255-m meteorological tower.The heat flux was found significantly decreased by haze （heavy pollution） or cloud,which tended to depress the development of PBL,while the repressed structure of PBL further weakened the diffusion of pollutants,leading to heavy pollution.This possible positive feedback cycle（more aerosols→lower PBL height→more aerosols） would induce an acceleration process for heavy ground pollution in megacities.     

高瓦斯矿发火区封闭时对瓦斯爆炸界限因素的影响

针对高瓦斯矿发火区封闭时常发生瓦斯爆炸事故,对影响瓦斯爆炸界限的因素进行实验,探索温度、压力、可燃气体(CO)、惰性气体(N2和CO2)等条件对瓦斯爆炸界限的影响规律。得出常温常压下瓦斯爆炸的体积分数下限为5%,瓦斯爆炸上限为13.5%,以及CO2的惰化效果比N2更好的结论。根据实验数据绘制混合气体的爆炸三角形,并进行新的惰化分区划分,不仅为火区封闭时防治瓦斯爆炸提供新的技术途径,而且能计算出使火区惰化时,所需惰性气体量,可对这些因素进行合理控制,有效地降低瓦斯爆炸危险性。