A central limit theorem for generalized multilinear forms

Let X₁, …, X_n be independent random variables and define for each finite subset I {1, …, n} the σ-algebra = σ{X_i : i ε I}. In this paper -measurable random variables W_I are considered, subject to the centering condition E(W_I ) = 0 a.s. unless I J. A central limit theorem is proven for d-homogeneous sums W(n) = Σ_{I = d}W_I, with var W(n) = 1, where the summation extends over all (_n^d) subsets I {1, …, n} of size I = d, under the condition that the normed fourth moment of W(n) tends to 3. Under some extra conditions the condition is also necessary.     

Sensitive analyses of agricultural chemicals by capillary electrochromatography

Capillary electrochromatography using a monolithic matrix was employed to develop a rapid and highly efficient separation methodology for the analyses of mixtures of agrochemical importance. Using this method, ppm‐ppb detection limits for urea, carbamate, and phenoxy acid herbicides were achieved without a preconcentration technique. The detection limits were further decreased to low‐ppb levels for the same class of compounds using an on‐column preconcentration technique.     

A NECESSARY AND SUFFICIENT CONDITION FOR THE COEXISTENCE OF A CLASS OF CUBIC CURVE SEPARATRIX CYCLES AND LIMIT CYCLES TO THE CUBIC SYSTEM

In this paper, we give the necessary and sufficient condition for the coexistence of a class of cubic curve separatrix cycles and limit cycles to the cubic system, and study their topological structures.     

Cyclical strategies in two-dimensional optimal control models: Necessary conditions and existence

This paper derives necessary conditions such that cyclical policies may be optimal in concave, two state variable (economic) control problems. These conditions identify four different routes. One major implication is that two of these four conditions may be met by separable models. This possibility has been overlooked so far. Therefore, even separable and structurally very simple models may be characterized by optimal cyclical policies. Indeed, it will be shown that stable limit cycles exist for concave and separable control problems.     

Super-Instantons, Perfect Actions, Finite-Size Scaling, and the Continuum Limit

We discuss some aspects of the continuum limit of some lattice models, in particular the 2DO(N) models. The continuum limit is taken either in an infinitevolume or in a box whose size is a fixed fraction of the infinite-volume correlation length. We point out that in this limit the fluctuations of the lattice variables must be O(1) and thus restore the symmetry which may have been broken by the boundary conditions (b.c.). This is true in particular for the socalled super-instanton b.c. introduced earlier by us. This observation leads to a criterion to assess how close a certain lattice simulation is to the continuum limit and can be applied to uncover the true lattice artefacts, present even in the so-called “perfect actions”. It also shows that David’s recent claim that superinstanton b.c. require a different renormalization must either be incorrect or an artefact of perturbation theory.     

The topology of the sectional streamlines

The unsteady, three-dimensional full Navier-Stokes equations are solved using a Beam-Warming implicit algorithm in this paper. Computations of the flow over a 76° sweep delta wing at 36.5° angle of attack is presented. The sectional streamlines are depicted and the evolution of the instantaneous crossflow topology of the leading-edge vortex is analyzed. It is found that, along the axis, the topology of the primary vortex alters several times starting from stable focus near the apex to unstable focus, and lasts back to stable focus near wake edge; The stable limit cycle and unstable limit cycle are shown in this evolution. These various altering topologies stem from the stretching and compression of the vortex core.     

HL—1装置密度极限破裂分析

HL-1装置上观测到大量的密度极限破裂放电。其主要特性是破裂前偏离几何中心的磁面位移很小,中心区总是观测到锯齿现象,破裂后,其电流中断时间大于20ms。本文详细分析了出现在电流上升段,坪段及下降段密度极限破裂的特征。其中一类是由于辐射功率超过加热功率所确定的村上极限,没有观测到先兆振荡;另一类是由于约束变坏所确定的赫吉尔极限,可观测到驰豫几毫秒的先兆振荡,这类放电破裂后多数能恢复。该装置运行的最大村上参数是0.35×10~(20)m~(-2).T~(-1)。     

Thermodynamics and Hydrodynamics (Statistical Foundations): 4. Kinetic Processes in Multicomponent Systems

We use the BBGKY hierarchy and the mass, momentum, and intrinsic energy conservation laws, which are consequences of this hierarchy, to obtain the hydrodynamic equations for multicomponent systems and the diffusion equations. We formulate several restrictions on the thermodynamic equations for irreversible processes.     

Finite-dimensional representations of a shock algebra

Abstruct The algebra describing a shock measure in the asymmetric simple exclusion model, seen from a second class particle, has finite-dimensional representations if and only if the asymmetry parameterp of the model and the left and right asymptotic densitiesp _± of the shock satisfy [(1−p)/p] ^r =p ₋(1−p ₊)/p ₊(1−p ₋) for some integerr≥1; the minimal dimension of the representation is then 2r. These representations can be used to calculate correlation functions in the model.     

发光二极管诱导荧光检测器的研制

探讨了以亮度发光二极管为诱导荧光检测激发光源的可行性，考察了直流驱动和脉冲驱动发光二极管(LED)对输出光强的影响以及LED塑料保护层厚度对输出光强的影响。发现脉冲驱动比直流驱动能提高光强3倍，无塑料保护层相对有保护层可提高光强2．5倍。采用毛细管电泳柱上检测方式对检测系统进行了评价，最小检出浓度为0．18μmol／L。结果表明该装置可以满足普通分析需求。