一类多分子反应模型的闭轨的存在性

研究了一类多分子反应模型｛ｄｘ／ｄｔ＝１－ｘ＾ｐｙ＾３ ｄｙ／ｄｔ＝α（ｘ＾ｐｙ＾３－ｙ）（α〉０,ｐ∈Ｎ）的闭轨的存在性。结论是,存在α＾＊∈（ｐ／２,α０］,使当ｐ／２〈α〈α＾＊时,该系统有稳定的极限环;当α〉α０或０〈α〈α１〈ｐ／２时,该系统没有极限环,其中α０,α１与α＾＊的表达式见正文。     

RF等离子体CVD合成氮化碳薄膜的XPS研究

采用射频等离子体化学气相沉积技术合成氮化碳薄膜，测量其Ｘ射线光电子能谱（ＸＰＳ），获得两组Ｃ（１ｓ）电子和Ｎ（ｌｓ）电子结合能，它们是Ｅ（Ｃ＾１）＝３９８．０￣３９８．７ｅＶ，Ｅ（Ｃ＾２）＝２８４．６￣２８４．８ｅＶ；Ｅ（Ｎ＾１）＝３９８。０￣３９８．７ｅＶ，Ｅ（Ｎ＾２）＝４００．０￣４００．９ｅＶ。证实了薄膜中碳原子存在ｓｐ＾３杂化轨道成键和ｓｐ＾２杂化轨道成键两种键合形式。该方法合成的氮化碳薄     

N×N二维DFT的多项式变换算法及其并行算法（N=2^t·3^s）

详细讨论了Ｎ×Ｎ二维ＤＦＴ的多项式变换及其并行算法，这里Ｎ＝２ｔ·３ｓ，将这种算法推广到Ｎ＝ｐ１＾ｔ·ｐ＾２＾ｓ的情形（ｐ１，ｐ２为互异素数）。与通常的行列算法比较，本文算法乘法量减少约５０％，加法量略有增加。     

解对称带状Toeplitz矩阵特征值问题的一种并行算法

提出了解对称带状Ｔｏｅｐｌｉｔｚ矩阵特征值问题的一种新的并行算法。该算法首先将Ｔｏｅｐｌｉｔｚ矩阵嵌入到一个更高阶的对称循环矩阵,得到对称循环矩阵特征值之后,采用二分法计算Ｔｏｅｐｌｉｔｚ矩阵特征值。新算法的计算复杂性为Ｏ（ｒ＾３ｎ＾２／ｐ）,其中ｎ是矩阵维数,ｒ是半带宽,ｐ为处理机台数,并行加速比为Ｏ（ｐ）。文中给出了数值实验的结果。     

腐蚀磨损数学模型

测试了化学镀Ｎｉ－Ｐ合金静腐蚀、动腐蚀和腐蚀磨损试验结果。通过对试验结果的处理，建立了动腐蚀速率和腐蚀磨损速率与冲击速度Ｖ、介质浓度Ｃ的数学模型：Ｖ＝Ｋ１Ｖ＾ｎ１＋Ｋ２Ｖ＾ｎ２Ｃ＾ａ（ａ＝Ｋ３Ｖ＾ｎ３）。建立了腐蚀磨损速率Ｖｗｃ与纯磨损速率Ｖｗｏ、纯腐蚀速率Ｖｐｃ及动腐蚀速率Ｖｏｃ之间数学模型：Ｖｗｃ＝Ｖｗｏ＋Ｖｐｃ＋ＫｗｃＶｗｏ，Ｖｐｃ＝Ｖｗｏ＋（１＋Ｋｗ）Ｖｏｃ＋Ｋｗｃ（１＋Ｋｗ）ＶｗｃＶｏｃ     

求平面点集独立线段的一个联机算法

令Ｓ为一个有限平面点集合，线段Ｌ（ｐ，ｑ），ｐ，ｑ∈Ｓ称为Ｓ的一个独立线段当且仅当不存在两个端点在Ｓ中的线段与Ｌ（ｐ，ｑ）相交。本文给出了时间复杂度为Ｏ（ｎ＾２ｌｏｇｎ）和修正时间复杂度为Ｏ（ｎｌｏｇｎ）的联机算法。这一算法与已知的脱算法具有相同的时间复杂度。     

R^n中半线性椭圆方程Δu＋k（│x│）u^p=0注记

讨论了Ｒ＾ｎ（ｎ〉２）中半线性椭圆方程Δｕ＋ｋ（│ｘ│）ｕ＾ｐ＝０的正径向解的存在性与渐近性,２个定理分别改进了推广了前人相应的结果。     

合成硼碳氮体系薄膜的XPS研究

采用Ｘ射线光电子谱（ＸＰＳ）分析３００～５００℃等离子体源离子渗氮硼和碳化硼薄膜合成的氮化硼和硼碳氮薄膜。利用合成薄膜成分可控的特点,研究Ｂ、Ｃ、Ｎ对薄膜的ＸＰＳ影响。结果表明,ＸＰＳ分析合成氮化硼薄膜能够确定其化学组成,但不能确定ｓｐ＾２和ｓｐ＾３型键合结构特性;ＸＰＳ分析硼碳氮薄膜能够确定其成分和结构特性。在较高的工艺温度下,等离子体源离子渗氮合成的硼硕氮薄膜具有ｓｐ＾２和ｓｐ＾３型复合的键合     

扩展增长曲线模型中协差阵的最小模估计问题

考虑扩展增长曲线模型Ｙ＝Σ＾（ｍ，ｉ＝１）ＸｉｂＩＺ’ｉ＋Ｕε其中Ｘｉ，Ｚｉ，Ｕ均为已知矩阵，Ｒ（Ｚ１）∩←…∩←Ｒ（Ｚｍ），Ｂｉ是回归系数国，Ｙ＝（ｙ（１），…，（ｙ（ｎ））‘和ε＝（ε（１），…，ε（ｓ）’分别是ｎ×ｐ观测资料矩阵和ｓ×ｐ随机误差矩阵。     

极板负偏压对类金刚石薄膜性质的影响

用射频－直流辉光放电系统制备类金刚石薄膜，研究了极板负偏压（Ｖ）对类金刚薄膜性质的影响。结果表明，类金刚石薄膜的性质明显依赖于极板负偏压，在所研究的范围（－３００－９００Ｖ）内，随Ｖ绝对值的增加，薄膜的折射率，消光系数，生长速率，及硬度增加，电阻率下降，Ｖ的变化使膜中Ｈ一及ｓｐ＾３／ｓｐ＾２的比例发生变化，从而使膜的性质发生变化。     

Uncertainty of Cesium-Beam Time Standards Due to Beam Asymmetry

As a consequence of the spatial phase distribution in the resonators of cesium-beam time and frequency standards, the generated frequency depends on the specific path of the atomic beam. A change of the position of the atomic beam source may result in a beam displacement normal to the beam direction. For a deflection system consisting of a combination of quadrupole and hexapole magnets for two-dimensional beam deflection, the displacement of the center of mass of the beam resulting from a misalignment of the beam source is computed. To this end, the distribution of the beam intensity on the collector is first determined. It is shown that for the cesium-beam time and frequency standard CSI of the Physikalisch-Technische Bundesanstalt (PIB), the uncertainty of the position of the center of mass of the beam entails a contribution to the uncertainty of the standard of less than 1 X 10-15. The amount of the displacement of the center of mass of the beam can be determined from the decrease of the beam flux on the collector caused by an adjustment of the beam source.     

Potentials and Equations of State for Two Special Reference Configurations

On the basis of the mathematical formulation of the principle of reference invariance of the functions of state of deformed bodies, we consider two special representations of the potential of state in which the reference configuration is variable and related to the current state of the body. The first of these representations (natural) follows from the general representation of the potential of state if a current state of the basis is regarded as the reference state and the corresponding stress-free configuration is taken as the reference configuration. The second (strain-free) representation is obtained if the role of the reference configuration is played by the current configuration. For both representations, we deduce the equations of state in the form of expressions for stresses and the parameters of state connected with the basis parameters. As a constructive proof of the unconditional existence of the elastic potential, we deduce the expression for the elastic potential via the potential of state by using the natural potential of state. It is proved that the general system of equations of state consists of four independent systems of equations, namely, of the equations of elasticity, piezoeffects, stress-free distortion, and stress-free state.     

The inclusion of the effect of the evaporation coefficient on the rate of variation of droplet radius

The paper deals with the investigation of the effect of the evaporation (condensation) coefficient of droplet substance on the rate of unsteady variation of the radius of a spherical aerosol droplet in the cases of direct and indirect inclusion of this coefficient. It is found in both cases that the effect of evaporation coefficient is most significant at the initial instant of unsteady-state process of evaporation and of condensation growth of the droplet. At this instant, the size of spherical droplet has hardly any impact on the rate of variation of its radius. As the unsteady-state process continues, the effect of the evaporation coefficient on the rate of variation of the droplet radius depends significantly on the droplet size. The larger the droplet under consideration, the lower the effect of the evaporation coefficient on the rate of variation of its radius. The rates of variation, calculated for the same values of the evaporation coefficient but for different ways of inclusion of this coefficient, differ less for larger aerosol droplets. These methods of inclusion of the evaporation coefficient are considered for the process of slow evaporation of a droplet.     

Generalized RayleighWave Dispersion Analysis in a Pre-stressed Elastic Stratified Half-space with Imperfectly Bonded Interfaces

Within the framework of the piecewise homogeneous body model the influence of the shear-spring type imperfect contact conditions on the dispersion relation of the generalized Rayleigh waves in the system consisting of the initially stressed covering layer and initially stressed half plane is investigated. The second version of the small initial deformation theory of the three-dimensional linearized theory of elastic waves in initially stressed bodies is applied and the elasticity relations of the materials of the constituents are described by the Murnaghan potential. The magnitude of the imperfectness of the contact conditions is estimated through the shear-spring type parameter. Consequently, the influence of the imperfectness of the contact conditions on the generalized Rayleigh wave propagation velocity is studied through the influence of the values of this parameter. Numerical results on the action of the imperfectness of the contact conditions and the influence of the initial stresses in the constituents on the wave dispersion curves are presented and discussed. In particular, it is established that the magnitude of action of the imperfectness of the contact conditions under the influence of the initial stresses on the wave propagation velocity cannot be limited with corresponding ones obtained in the case where the contact between the constituents is complete and in the case where this contact is full slipping one. The possible application of the obtained results on the geophysical and geotechnical engineering is also discussed.     

有界窄带激励下的电磁开关系统主共振分析

以电磁开关系统为研究对象,研究电路与磁路耦合系统在有界窄带激励下的强非线性振动问题。建立电磁开关强非线性系统在有界窄带激励下的随机微分方程。应用改进的多尺度法得到系统的幅频响应方程,对窄带激励下系统主共振的稳定性进行计算,并分析系统各参数对系统主共振均方值的影响。结果表明,增大阻尼系数可以减小系统主共振的均方值;增大激励电压可以增大系统主共振的均方值;增大电阻可以减小系统主共振的均方值;增大随机扰动强度,极限环变化不大。     

Calculation of the number of cracks and their dimensional distribution in pulsed ductile fracture of a ring

The basic parameters of the shear fracture process of cylindrical shells under intense pulsed (particularly explosive) loads were evaluated on the basis of the proposal of a critical intensity of deformations based on the amount of the work of plastic deformation. The position of the front of fracture, the radius of fracture, the number of cracks in the ring and the number of divisions on the axis of the cylinder, and the size distribution of the number of cracks with and without taking into consideration their mutual intersection and also of the number of fragments of the cylindrical shell by weight were determined. As a first approximation the yield strength, the reduction in area, and the impact strength were used as the parameters characterizing the shell material. A comparison is given of the calculated data and the experimental for the number of through cracks in the ring and the weight distribution of the number of fragments of cylindrical shells.Translated from Problemy Prochnosti, No. 9, pp. 73–79, September, 1989.     

变参数下角接触球轴承保持架的稳定性与振动特性分析

保持架是角接触球轴承的重要元件之一,其引导间隙和兜孔间隙设计不合理会导致轴承运动失稳与共振。针对上述问题,在理论分析的基础上,结合滚珠、保持架和滚道之间的动态接触与变形关系,在ABAQUS软件中建立了7005型角接触球轴承的显式动力学模型,并提取了特定工况下该轴承内圈、保持架与滚珠的动态响应曲线;同时,研究了不同引导间隙和兜孔间隙下保持架的打滑率、质心涡动速度偏差比和各阶振动模态的固有频率。为了验证所建立的角接触球轴承显式动力学模型的准确性,对高速角接触球轴承各元件线速度的仿真值与理论值进行了对比。结果表明：随着引导间隙的增大,保持架的打滑率、质心涡动速度偏差比和各阶振动模态的固有频率均减小,保持架的稳定性增强,但共振风险增大;随着兜孔间隙的增大,保持架的打滑率增大,质心涡动速度偏差比变化不明显,各阶振动模态的固有频率减小,保持架的稳定性减弱,共振风险增大。高速角接触球轴承各元件线速度的仿真值与理论值的最大误差仅为0.099 6%,验证了所建立的显式动力学模型的准确性。研究结果可为高速角接触球轴承保持架的优化设计提供理论依据。     

侧滑角对超空泡航行体转弯运动沾湿区域的影响

为了提高通气超空泡航行体在转弯运动过程中空泡和航行体的运动一致性,基于有限体积法和VOF多相流模型,采用动态网格技术对航行体转弯运动的空泡形态特性进行了非定常数值模拟研究。通过对航行体沾湿区域的分析,揭示了沾湿区域形成的原因,利用空化器对空泡轴线的定向效应,提出了合理改变侧滑角减缓沾湿区域出现的具体方法。通过分析侧滑角和侧滑角速度对航行体沾湿区域的影响,提出了超空泡航行体转弯运动过程中,在给定偏航角条件下避免出现沾湿区域的侧滑角和侧滑角速度的适用范围,为进一步研究超空泡航行体机动运动问题提供参考。     

Thermoelastic contact of a retaining ring with a cylinder under the conditions of frictional heat generation

We give the mathematical statement and construct the solution of the static thermoelastic problem of contact interaction of an elastic retaining ring with a circular hollow cylinder inserted in it. The bodies are compressed by a load varying along the axis of the system under the conditions of load-free contact on the surface of the ring or along an arc of the circle. In the case where radial displacements of the contact surface of the retaining ring are approximated by displacements of the surface of a long circular hollow cylinder and the process of stationary frictional heat generation is taken into account, we reduce the posed problem to systems of integral equations whose structure is determined by the type of conditions of thermal contact. We propose a numerical algorithm for the solution of these systems and study the influence of the input parameters of the problem on the distributions of contact pressure and temperature. On the basis of these results, we make a conclusion that the influence of the character of variation of the compressive load along the axis on the distribution of contact pressure is significant in the case where the kinematic conditions of interaction of the bodies are described by the Hertz theory. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 36. No. 3. pp. 42–52, May-June, 2000.     

某多用途货车传动系扭振试验分析与优化

某多用途货车加速行驶时,在发动机转速1200 r/min～1500 r/min范围内,传动系出现明显振动,影响整车NVH品质.针对此问题在传动系关键节点处加装传感器,对车辆6个前进挡在加速工况下进行扭振测试,由数据处理获得传动系各部位的角加速度振幅随发动机转速变化的关系.分析获得各部位振动的主要阶次,确定发动机2阶激励...