自适应近似树

在大规模多媒体数据库中进行基于内容的检索，高维数据牵引结构的研究是重要问题，提出了一种有效的高维索引结构－自适应近似树，阐述了它的结构，给出了构建和检索算法，它结合了树结构和顺序检索的共同优点，针对不同的数据分布情况可以自适应地调整结构，维数较低或数据分布偏斜较大时它呈现树的结构，高维或数据分布密集时呈现顺序扫描的结构，以达到更优的检索效率，在结构上，对MBR使用了压缩存储的方法以节省存储空间，在算法中充分利用了空间划分是MBS和MBR共存的特点，减少了大量复杂的计算，从而大大提高检索效率。     

Cellular automaton modeling of computer network

The dramatically increasing growth of computer network has brought us more and more complex systems that reveals plenty of nonlinear complex phenomena. On the other hand, cellular automaton model used to be in the study of a variety of nonlinear and spatially extended systems. This paper proposes a simplified cellular model for computer network, namely the NaSch network model, which is originated at the NaSch model of road traffic. Typically, the NaSch network model is a one-dimension cellular automaton and consists of two kinds of cells, i.e. node cell and link cell. In this paper, the node cell stands for switch nodes in computer network, such as routers and switchers, while the link cell is the abstract of the lines of communication among these switch nodes. The simulation results show that this model indeed captures some of properties of flux of computer networks. The space-time plots illustrate that the randomization in this modeling plays an important role in the emerging of self-organization of congestion. It also demonstrates that the density of packet is another key factor to having influence on congestion. On the contrary, the boundary condition has few contribution to our model.     

室内污染物质扩散数值模拟的有限元法

介绍了一种预测室内空气污染浓度分布的数值方法，算法有一定特点，即：流动用时均流方程及ｋ—ε模型来描述，用有限元法离散基本方程，用罚函数法处理不可压缩条件，与罚函数对应的项采用降阶积分，对ｕ—ｖ方程与ｋ—ε方程交替进行计算。用作者编制的程序对室内有污染源时污染物质的扩散进行了计算，与国外的同类计算相比，结果较好。     

Analysis of the ∈-Expansion in Turbulence Theory: Approximate Renormalization Group for Diffusion of a Passive Scalar in a Random Velocity Field

The validity of the -expansion in the turbulence problem is discussed using the example of diffusion of a passive scalar in a random velocity field. A generalization of Wilson's rule for calculating a diagram of arbitrary order is introduced. The resulting perturbation series, while having zero radius of convergence, is summed exactly yielding amplitudes which differ from those obtained to lowest order in the -expansion by only a few percent. The properties of the expansion are analyzed in detail and it is shown that various subsets of diagrams, while differing by an infinite number of terms, give close results in the vicinity of the fixed point. This indicates nontrivial compensation of high-order interactions in turbulence. The irrelevance of high-order couplings is demonstrated for arbitrary values of . The quality the approximation is tested by comparison with numerical experiments on diffusion of a passive scalar in a band-limited random velocity field in the limit of infinite Peclet number.     

Theoretical consistency test of steam transport properties

The kinetic theory of polyatomic gases is used to test the mutual consistency of the thermal conductivity, viscosity and specific heat of low-pressure steam from 100° to 700°C. No inconsistency exists within the cited tolerances of the skeleton tables recommended by the Sixth International Conference on the Properties of Steam, but there is some basis for suspecting that the high-temperature thermal conductivity values are slightly low. Methods for tightening the consistency bounds are suggested.     

Heat Inputs to Sub-mK Temperature Cryostats and Experiments from γ-Radiation and Cosmic Ray Muons

We measured the spectrum of energies deposited by -radiation, emanating from radioactive materials in the laboratory that houses our mK cryostat, and by cosmic ray muons. This allows us to quantify the heat input that adversely affects the lowest temperature accessible in sub-mK experiments. We use our nuclear stage, stage plate and experimental cell as a prototype model system, and calculate the power deposited due to low energy (below 2.65 MeV) background radiation quanta (~20 pW). This is significantly less than the power (~120 pW) deposited in the nuclear and experimental stages by muons. Installation of a 5 cm thick lead wall around the cryostat reduced the energy due to the flux of quanta by a factor of ~10 to ~2 pW, and the number of quanta by a factor of ~20. The lower energy, soft cosmic ray component was also affected by introducing the same thickness of lead, reducing the overall count of cosmic ray derived particles by ~15% and the heat leak to ~100 pW.     

Pietra Serena Mining in Fiesole. Part II: Geological Situation

The results are presented for the investigations into the geological estimate of Macigno formation representing an Oligocene-Miocene turbiditic sequence of the Northern Apennines, from the coarse-graded beds of which the Pietra Serena quarry stone was mined. It is shown that the sedimentological features, the physico-mechanical properties, and the mineralogical composition of rocks govern the distinctions in the operating performances.     

Experience with Construction of Underground Sections of Buildings by the “From Top Down” Scheme

Experience gained with the method of installing the underground section of a building from the top down is described in an example of the construction of specific projects in Moscow, design, construction and monitoring problems are exposed, advantages and disadvantages of this method are indicated, and observational data are cited for the settlements of existing buildings located within the zone of influence of new construction.     

亚45 nm技术节点平面式硅基CMOS电路制作的材料选择

随着45nm技术的临近，减小单个晶体管尺寸以提高晶体管集成度的方法逐渐达到物理极限。传统掺杂多晶硅，二氧化硅栅结构因硼杂质扩散穿透、多晶硅耗尽和电子隧穿等效应使深亚微米器件的性能退化。此外，沟道载流子迁移率退化也阻碍Si基MOS性能的提升。因此，需采用高k介质、金属栅和应变硅等新材料、新技术以改善Si基MOS管性能。本文在介绍这3种新材料优势的同时，分析了适合未来平面式硅基CMOS技术中的高介电常数材料和金属栅材料的种类，指出了未来电路中新材料的进一步发展方向。     

基于网络Voronoi图的道路网络连续k近邻查询

道路网络中的连续查询是查找在一条路径上满足查询条件的对象。它是空间网络数据库中的一种重要查询类型。现提出了道路网络中基于k阶Voronoi图的连续k近邻查询方法，该查询方法用分枝限界的思想动态地创建局部Voronoi图，降低了查询代价。