~（60）Co辐照对聚四氟乙烯表面润湿性的影响

研究了具有低表面能的氟聚合物聚四氟乙烯（ＰＴＦＥ），经６０Ｃｏγ射线辐照后表面状态的变化，以及其对液体介质蒸馏水的润湿性。较详细地论述了辐照后表面粗糙度、结晶度以及表面化学基因等不同因素对ＰＴＦＥ表面润湿性的影响。通过对ＰＴＦＥ及其表面的红外、Ｘ光衍射，表面粗糙度的分析，弄清了辐照后ＰＴＦＥ表面化学基团的改变对有机氟聚合物表加的润湿性影响很大，而粗糙度和结晶度的变化对润湿性影响较小。     

Validation of 3-D curved objects: CAD model and fabricatedworkpiece

This paper proposes a new method to describe and identify a 3-D curved object for the purpose of validating a fabricated object to the design specification. Curved 3-D objects are, in general, difficult to represent and identify because they lack distinct properties such as edges, planes, or cylindrical surfaces which are the building blocks in representing objects. In this paper, the authors propose to use principal axes of a 3-D object to establish a reference for the representation. A method of obtaining an inertia matrix from a 3-D range image is developed. The unique set of principal axes is obtained from the inertia matrix of an object with an arbitrary 3-D position and orientation, and the object can be described uniquely on these principal axes. On the principal axes, an object is described by a set of features describing the shape of the object such as spine, section size, section orientation, and section contraction. The features are used for comparing two objects for the validation purpose. The authors also propose a direct measure of similarity between two objects as a mean-squared difference of radii. As an experiment, two 3-D object models are designed through a CAD package, and fabricated objects are compared with the designed models for validation purposes     

Micromechanical characterisation of fibre/matrix interfaces

Theoretical analyses for the single fibre pull-out and push-out models under monotonic loading are given which are based on a shear-lag analysis in a fracture mechanics approach considering non-constant friction at the debonded interface as a result of fibre Poisson contraction (or expansion). The solutions allow the determination of typical fibre/matrix interfacial properties such as the interfacial fracture toughness, G_ic, the coefficient of friction, μ, and the residual clamping stress, q₀. Under cyclic loading the interfacial properties are expected to degrade as a result of repetitive abrasion, and a power law function is assumed between μ and the number of elapsed cycles, N. However, G_ic is assumed to be unaffected and a fracture mechanics based debond criterion is derived for the relationship between the external applied stress, the debond length and the reduced friction coefficient for both fibre pull-out and fibre push-out. In addition, the relative displacements between the free fibre end and the matrix top are obtained for cyclic fatigue when the fibre is loaded and unloaded. A relationship obtained for the protrusion (or intrusion) length in fibre pull-out (or push-out) experiments allows the severity of the interface frictional degradation to be evaluated and characterised. Similarities and differences in the frictional degradation behaviour between fibre pull-out and push-out are also identified.     

6M32(51)氮氢气压缩机系统的技术改造

1 机组简介 6M32(51)-190/320-BX型氮氢气压缩机的基础件采用德国博尔格公司的专有技术,具体参数如下: 压缩介质:氮氢气,压缩级数:6级;转速:375rpm;行程:320mm,轴功率:2920kW,容积流量:190m~3/min;气量调节:回路调节,冷却填料润滑油:1.95 kg/h;重量:主机69.45t,     

Performance of trellis coded-8PSK with cochannel interference

The performance of trellis coded-8PSK in the presence of cochannel interference is analyzed and compared with the performance of uncoded QPSK. The analytical expressions are derived and supported by simulating the bit error rate performance of different TC-8PSK systems. The analytical and simulation results show that TC-8PSK is slightly more robust to cochannel interference than uncoded QPSK     

Manipulation of microenvironment with a built-in electrochemical actuator in proximity of a dissolved oxygen microsensor

Biochemical sensors for continuous monitoring require dependable periodic self diagnosis with acceptable simplicity to check its functionality during operation. An in-situ self-diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electrochemical actuation electrode. With a built-in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments, called the oxygen-saturated or oxygen-depleted phases, can be created by water electrolysis, depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton) and the feasibility of the proposed concept is demonstrated in a physiological solution. The sensor responds properly during the oxygen-generating and oxygen-depleting phases. The use of these microenvironments for in-situ self-calibration is discussed to achieve functional integration, as well as structural integration, of the microsensor system.     

On-line dead-time compensation method using disturbance observer

A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuit and off-line experimental measurement, disturbance voltages in the rotor reference dq frame caused by the dead time and nonideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Simulations and experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.     

An important factor affecting synergism on coprocessing of Taiheiyo coal with Athabasca oil sand bitumen

A series of mixtures of Japanese subbituminous Taiheiyo coal and Athabasca oil sand bitumen (AOB) with various coal concentrations (0–100 wt%) was coprocessed in a 70 ml autoclave at 420°C for 1 h in the presence of H₂ (50 kg/cm² at room temperature) and sulfided Ni---Mo/Al₂O₂ catalyst. The mixture containing 2 wt% coal produced the largest amount of hexane soluble fraction (HS) and the smallest amount of benzene insoluble fraction (BI). Thus, a synergistic liquid production occurred for this mixture with 2 wt% coal by suppressing the retrogressive reactions which proceeded for pure AOB. The HS obtained from mixtures with 2–30 wt% showed higher H/C ratios and lower heteroatom contents than those obtained from pure AOB and the mixtures with more than 30 wt% coal. The amounts of transferable hydrogen contained in the mixtures were estimated using anthracene as a hydrogen acceptor. The mixtures with 2–10 wt% coal contained higher amounts of donor hydrogen than pure AOB. The HS yield from the various mixtures was correlated with the amount of donor hydrogens contained in the mixtures, except for the mixture with 10 wt% coal. Thus, the important factor which results in synergism is suggested to be the amount of donor hydrogens contained in the feed mixtures.