数控车床编程中三种编程方法对零件外轮廓加工精度的影响

数控车床编程的教学中常采用三种不同的外轮廓程序编写方法,本文主要介绍这三种方法,并通过分析加工过程中所出现的问题来比较三种不同的编程方法对于零件加工精度的影响。     

Novell网上实现无盘Win95启动

从实践角度详述了在Novell网上实现无盘Win95启动的安装设置过程     

一类特征波传播方程的数值解

本文在小振幅波及缓变海底的假设下对两种不同形状的区域给出了浅水海浪传播方程的差方方法，得到了区域的波高和波向的数值解。     

慢性氟中毒致学习记忆损伤的脑内突触机制

探讨了慢性氟中毒致学习记忆损伤的脑内机制.选用初断乳雄性SD大鼠192只,随机分为4组:1个对照组,饮用自来水;3个分别饮用15,30和60 mg/L Na F溶液的染氟组.染氟期为18月.每3月用开场行为和Morris水迷宫法检测大鼠的学习记忆行为;分别在染氟中期(9月)和染氟结束后(18月)分2批断头处死大鼠,进行脑海马突触体膜流动性和海马CA3区突触后致密蛋白-95(PSD-95)表达水平等检测.结果表明:慢性氟中毒致大鼠自发活动和探究行为显著或极显著抑制,空间学习记忆能力显著下降;脑海马突触膜流动性、PSD-95表达水平均显著下降.提示慢性氟中毒致脑海马突触体膜流动性和突触后致密蛋白-95表达水平的改变可能是慢性氟中毒致学习记忆损伤的脑内突触机制之一.     

Intermediate statistics as a consequence of deformed algebra

We present a formulation of deformed oscillator algebra which leads to intermediate statistics as a continuous interpolation between Bose-Einstein and Fermi-Dirac statistics. It is deduced that a generalized permutation or exchange symmetry leads to the introduction of the basic number and it is then established that this in turn leads to the deformed algebra of oscillators. We obtain the mean occupation number describing the particles obeying intermediate statistics which thus establishes the interpolating statistics and describe boson-like and fermion-like particles obeying intermediate statistics. We also obtain an expression for the mean occupation number in terms of an infinite continued fraction, thus clarifying successive approximations.     

On the 3-restricted edge connectivity of permutation graphs

An edge cut W of a connected graph G is a k-restricted edge cut if G−W is disconnected, and every component of G−W has at least k vertices. The k-restricted edge connectivity is defined as the minimum cardinality over all k-restricted edge cuts. A permutation graph is obtained by taking two disjoint copies of a graph and adding a perfect matching between the two copies. The k-restricted edge connectivity of a permutation graph is upper bounded by the so-called minimum k-edge degree. In this paper some sufficient conditions guaranteeing optimal k-restricted edge connectivity and super k-restricted edge connectivity for permutation graphs are presented for k=2,3.     

Combinatorial constructions of fault-tolerant routings with levelled minimum optical indices

The design of fault-tolerant routings with levelled minimum optical indices plays an important role in the context of optical networks. However, not much is known about the existence of optimal routings with levelled minimum optical indices besides the results established by Dinitz, Ling and Stinson via the partitionable Steiner quadruple systems approach. In this paper, we introduce a new concept of a large set of even levelled -design of order v and index 2, denoted by -LELD, which is equivalent to an optimal, levelled (v−2)-fault-tolerant routing with levelled minimum optical indices of the complete network with v nodes. On the basis of the theory of three-wise balanced designs and partitionable candelabra systems, several infinite classes of -LELDs are constructed. As a consequence, the existence problem for optimal routings with levelled minimum optical indices is solved for nearly a third of the cases.     

First order logic without equality on relativized semantics

Let $\alpha \ge 2$ be any ordinal. We consider the class ${\mathsf{Drs}}_{\alpha }$ of relativized diagonal free set algebras of dimension α. With same technique, we prove several important results concerning this class. Among these results, we prove that almost all free algebras of ${\mathsf{Drs}}_{\alpha }$ are atomless, and none of these free algebras contains zero-dimensional elements other than zero and top element. The class ${\mathsf{Drs}}_{\alpha }$ corresponds to first order logic, without equality symbol, with α-many variables and on relativized semantics. Hence, in this variation of first order logic, there is no finitely axiomatizable, complete and consistent theory.     

High room-temperature pyroelectric response of MgO-modified Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ceramics

The dielectric and pyroelectric responses of MgO-modified Pb_0.99(Zr_0.95Ti_0.05)_0.98Nb_0.02O₃ ceramics were investigated near F_R(LT)–F_R(HT) phase transition. It was found that MgO additive reduced the F_R(LT)–F_R(HT) phase transition temperature from 41 °C to room temperature (24 °C). Superior room-temperature pyroelectric properties were obtained in the composition of 0.10 wt% MgO addition without DC bias. The largest pyroelectric coefficient, 65 × 10⁻⁸ C cm⁻² K⁻¹, was detected. Accordingly, the detectivity figures of merit F_d had maximum values of 20 × 10⁻⁵ Pa^−1/2, and especially the voltage responsivity F_v = 0.91 m²C⁻¹ is the highest value reported so far among all pyroelectric materials. It shows promising potential for application in uncooled pyroelectric infrared detector.     

Dynamic allocation strategy based on pre-allocation and agent to implement Ada95's distributed computing

0　IntroductionFortheimplementofdistributedcomputingofAda95 ,wemadetheresearchoncurrencyofAdaprogram ,themodelofdistributingofcomputingandthesafetyofdistributedcomputingofAda95 [1 ] .Wealsodevelopedapre allocationstrategyfordistribut edcomputingofAda95 [2 ] .Foritisunavoidablethatsomedynamictasksoccurindistributedcomputing[3] ,wemusthaveastrategytodealwithit.So ,wefurthermadetheresearchofdynamicallocationstrategythatbasedonAgent.WetrytouseAgentinAda95’sdis tributingcomputing.Thekeytechnol…