临近空间单粒子效应的数值模型和电路模拟

针对临近空间单粒子效应进行了数值模型仿真和特征尺寸为0.1 μm的反相器电路的脉冲注入模拟研究。数值仿真结果表明器件临界电荷随着工作电压的降低而减小,敏感横截面随着临界电荷的降低而逐渐增大。临近空间微电子器件的单粒子翻转概率随敏感横截面增大而上升,但其又随临近空间高度的增加而下降。此外,利用SPICE软件脉冲注入模拟观察到了反相器电路的单粒子翻转现象。所得结论有助于深入研究临近空间的单粒子效应并为器件抗辐射加固提供了理论依据。     

二维渗流中的最短开穿透

在二维边渗流模型中，设／ｒｎ／＝ｍｉｎ（／ｒ／：ｒ是正方形「０，ｎ」＾２的开穿透），这里／ｒ／表示ｒ的长度，本文证明了在上临界状态有ｌｉｍＥ／ｒｎ／／ｎ＝λ，在临界状态时，我们对Ｅ／ｎ／给出了上界，并对一个ｒｎｒｎ给出了Ｅ／ｒｎ／的下界。     

等截面垂直管道中气粉流的临界管长

考虑重力和摩擦力的影响，建立了描述垂直管道中气粉流行为的数学模型，采用马赫数检验法，确定了产生摩擦壅塞时的临界管长，计算表明，当气粉流以不同方式喷入相同的冶金熔池时，底吹垂直管道比顶吹垂直管道需要更大的临界管长。     

Study on the Predicting System of Breaking Chip When PCD Tool Cutting Aluminum Alloy

In the field of automobile manufacture, during the aluminum alloy cutting, chip forming and breaking process are very complicated. It is affected by many facto rs. Automatic machining process can not be carried through if the chip enlaces t he workpiece or the tool. So the chip control and breaking are key technology. P CD tool has many traits, such as high cutting efficiency, machining precision an d wearability. It is desired that it be used for machining coloured metals.The p aper present the study of p...     

THE GLOBAL THEOREM OF A.N.BERLINSKII

ＳｏｃａｌｔｈｅＢｅｒｌｉｎｓｋｉｔｈｅｏｒｅｍｆｏｒｐｌａｎａｒｑｕａｄｒａｔｉｃＳｙｓｔｅｍ（ＱＳ）ｉｓ：ＴｈｅｏｒｅｍＡ［１］ＳｕｐｐｏｓｅｔｈａｔａＱＳｈａｓ４ｆｉｎｉｔｅｃｒｉｔｉｃａｌｐｏｉｎｔｓ（ＣＰｓ），Ｉｆｔｈｅｑｕａｄｒｉｌａ...     

双参数随机Sierpinski垫的相位曲线

引入双参数随机置换，考虑了具有参数ｐ，ｑ的随机Ｓｉｅｒｐｉｎｓｋｉ垫的各种形态的相位，讨论了ｐ，ｑ跨跃某些相位曲线时，其构成形态的变化情形，它包括了ｑ＝０的Ｓｉｅｒｐｉｎｓｋｉ垫和ｑ＝ｐ的Ｍａｎｄｅｌｂｒｏｔ渗流模型。     

Logarithmic corrections for dilute uniaxial ferromagnets at the critical dimension

The leading logarithmic corrections to the critical behavior of a dilute uniaxial (Ising) ferromagnet in the disordered phase are derived using renormalization group methods. The values of the exponents in the logarithmic terms differ from those given by previous authors.     

Boundary-Value Problem of Drainage in a Fresh Groundwater Fringe above Saline Groundwater

A multiparameter boundary-value problem of fresh infiltration water seepage in a drained fringe above quiescent saline water is solved in the direct statement and studied in detail.     

Unconventional antiferromagnetic correlations of the doped Haldane gapsystem Y 2 BaNi 1 - x Zn x O 5

We make a new proposal to describe the very low temperature susceptibility of the doped Haldane gap compound Y₂BaNi_1-xZn_xO₅. We propose a new mean field model relevant for this compound. The ground state of this mean field model is unconventional because antiferromagnetism coexists with random dimers. We present new susceptibility experiments at very low temperature. We obtain a Curie-Weiss susceptibility χ( T ) ∼ C /(Θ + T ) as expected for antiferromagnetic correlations but we do not obtain a direct signature of antiferromagnetic long range order. We explain how to obtain the “impurity” susceptibility ( T ) by subtracting the Haldane gap contribution to the total susceptibility. In the temperature range [1 K, 300 K] the experimental data are well fitted by T ( T ) = C _imp 1 + T _imp / T . In the temperature range [100 mK, 1 K] the experimental data are well fitted by T ( T ) = A ln( T / T _c ), where T _c increases with x. This fit suggests the existence of a finite Néel temperature which is however too small to be probed directly in our experiments. We also obtain a maximum in the temperature dependence of the ac-susceptibility ( T ) which suggests the existence of antiferromagnetic correlations at very low temperature. Received 17 July 2001     

The innovation research of financial early-warning index measurement

The period economic fluctuation is vital for an enterprise to exist and further develop,it directly affect the enterprise financial health.So,it is significant to build up financial early-warning index and measure the warning condition that the enterprise faces and take the effective measures to eliminate. We criticize Altman's Z calculating model and build up some new indexes for enterprise financial early-warning condition measuring and making sound decision.