本钢炼焦煤最佳配比分析

结合本钢的生产实际，对炼焦煤的最佳配比作了比较具体的分析，同时对资源，质量、成本也作了比较详细的调查，并提出了本钢焦化厂最佳配煤比方案，由此可看出，最大限度地降低采购成本，继续开发合理的配煤比例，具有广阔的前景。     

论BFe30—1—1冷凝管生产工艺及其改进的途径

论述了ＢＥｅ３０－１－１冷凝管生产工艺的优点及主要问题，对现行工艺提出了改进方案。     

FATIGUE CRACK GROWTH UNDER MODE II LOADING

Abstract— The behavior of fatigue crack growth for low and medium carbon steels, an austenitic stainless steel and an aluminum alloy under pure Mode II loading was investigated experimentally, using cruciform specimens. The results show that under pure Mode II loading, fatigue crack propagation has three possibilities, namely, bifurcation into two branches, propagation along the original Mode II direction, and the mixture of these two situations, depending on the material. The growth rate da/dN vs. ΔK_II relation for Mode II propagation is similar to a Pans type law for Mode I growth. Fractographic observations by optical microscopy and SEM were made also on all specimens tested. When a crack branched, striations parallel to the crack front which were often associated with Mode I fatigue crack growth were observed and long marks parallel to the crack propagation direction were also found for slanted fracture surfaces. When a crack propagated along the original Mode II direction, many frictional marks parallel to the crack propagation direction were observed.     

An ARQ scheme using combined QPSK and BPSK transmissions

We propose a hybrid ARQ scheme which uses QPSK modulation for the first transmission and BPSK modulation for retransmissions. The throughput performance of the proposed ARQ scheme is better that those of ARQ schemes purely using QPSK modulation or purely using BPSK modulation for transmissions. Furthermore, the proposed scheme does not require any operation of error correction as usually required in hybrid ARQ schemes. Therefore, the ARQ scheme proposed in this paper can be easily implemented     

Formula for two-carrier third-order intermodulation distortion in semiconductor laser diodes

Formulas for the two-carrier third-order intermodulation distortion in semiconductor lasers have been reported by many authors. The authors refine the formula further and illustrates the difference in results arising from the refinement, for typical laser parameters.<>     

A new notation for transform matrix and definitions of related operations

New transform matrices and their multiplications and inversion are defined. Properties of these matrices and operations are derived. The new notation is suitable for both conceptual formula derivation and actual computation. An example of using the new notation for computation of kinematics of robotic manipulators is given. © 1994 John Wiley & Sons, Inc.     

Optimization — a tool in advanced materials technology

This paper demonstrates the use of simple optimization techniques in the production of two advanced materials - a fibre-reinforced composite laminate and a transformation toughened ceramic - having enhanced mechanical properties. Both example materials are based on a brittle matrix prone to cracking at very low applied stresses. The optimization process aims at altering the microstructure so that the materials have enhanced resistance to crack propagation without any undesirable side effects.     

A probabilistic method for the design of power grounding systems

An improved multivariable, probabilistic method for the safety analysis of power grounding systems is presented. The application of this method is demonstrated in four examples. The first three examples illustrate the practical evaluation of one new and two existing substation grounding grids when the substation is connected to an overhead distribution system. The fourth example ascertains the relative impact of a difference between the S curve of IEC Publication 479 and Dalziel's equation for the allowable body current used in ANSI/IEEE Std 80-1986 on the validity of an exposure model based on the requirements of Std 80. In this example, the statistical data on ground faults have been taken from actual system records. Further possible refinements of the exposure model are discussed     

Cardiorespiratory effects of conventional and high frequency ventilation in rabbits with bilateral pneumothoraces and surfactant depleted lungs

We compared high frequency ventilation (HFV) to conventional mechanical ventilation (CMV) under normoxic and normocapnic condition in surfactant depleted rabbits with bilateral pneumothoraces. We hypothesized that lower airway pressures would be required with HFV under these conditions. We applied CMV and HFV in 8 anaesthetized rabbits with a prototype ventilator at frequencies of 30, 100, 200, and 300 cycles/min. A positive end-expiratory pressure (PEEP) just below the pressure sufficient to open the air leak from the pneumothoraces was applied at all frequencies. Airway pressures, gas exchange, heart rate, and mean arterial pressure were recorded. Peak airway pressure decreased significantly from 2.50 to 2.10 kPa when the frequency of ventilation was increased from 30 to 300 cycles/min. There were no significant changes in mean airway pressure, PaO2, arterial pH, heart rate, and mean arterial pressure when HFV was compared to CMV. In conclusion, during HFV peak airway pressures measured at the mouth were decreased. Our ability to maintain adequate gas exchange in the face of ongoing pulmonary air leaks may reflect lower alveolar pressures.     

A MULTIAXIAL FATIGUE DAMAGE MODEL FOR ORTHOTROPIC MATERIALS UNDER PROPORTIONAL LOADING

A new multiaxial fatigue damage model for orthotropic materials is proposed based on the strain vector. Six material constants are included in the model. These material constants represent the dependence of fatigue resistance on material orientation, and they can be obtained by conducting strain-controlled uniaxial fatigue tests along the three principal orthotropic directions of an orthotropic material. The model can also be transformed in new coordinate systems to predict the fatigue lives of new material orientations. Biaxial low-cycle fatigue tests are conducted to verify the model. The prediction of the model agrees with the experimental results reasonably well.