压缩应力下（Tb,Dy）Fe2磁致伸缩的研究

本文利用自制的磁致伸缩测量仪和“ｊｕｍｐ”效应测量仪研究了在一定压强了多晶（Ｔｂ、Ｄｙ）Ｆｅ２棒的磁致伸缩,发现加压时,在一定工艺条件下制作的（Ｔｂ、Ｄｙ）Ｆｅ２棒会有磁致伸缩的变化。卸载后经过热处理,磁致伸缩值在不加压时也会维持一个高值。     

辐射换热的波长匹配问题

由于水的选择性吸收特性,辐射换热中水份波长匹配一直是一个有分歧的问题。文章通过理论与计算论证了这个问题,得出的结论否定了波长匹配的重要性。     

浅析40T支架搬运车液压系统油温变化对其效率的影响

介绍了油温变化对40T支架搬运车液压系统油液黏度、液压介质和橡胶类密封件的影响,分析了液压系统的总发热功率、总散热功率,结合动态热平衡的计算,找出了液压系统总效率与油温变化之间的关系,并给出其函数关系式。根据这种关系,通过一种工况的油温实测数据取样,计算出相应的效率值,定量地验证了液压系统油温变化引起效率变化的关系,得出了总效率随着温度变化而变化的结论,即温差增大时,总效率降低;温差减小时,总效率增大。通过该结论可以全面掌握系统的工作状态,通过降低油温有效提高效率。     

Thermal and cardiovascular strain imposed by motorcycle protective clothing under Australian summer conditions

Motorcycle protective clothing can be uncomfortably hot during summer, and this experiment was designed to evaluate the physiological significance of that burden. Twelve males participated in four, 90-min trials (cycling 30 W) across three environments (25, 30, 35 °C [all 40% relative humidity]). Clothing was modified between full and minimal injury protection. Both ensembles were tested at 25 °C, with only the more protective ensemble investigated at 30 and 35 °C. At 35 °C, auditory canal temperature rose at 0.02 °C min^?1 (SD 0.005), deviating from all other trials (p < 0.05). The thresholds for moderate (>38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 min (SD 20.6) and 180 min (SD 33.0), respectively. Profound hyperthermia might eventuate in ~10 h at 30 °C, but should not occur at 25 °C. These outcomes demonstrate a need to enhance the heat dissipation capabilities of motorcycle clothing designed for summer use in hot climates, but without compromising impact protection.

Practitioner’s Summary:

Motorcycle protective clothing can be uncomfortably hot during summer. This experiment was designed to evaluate the physiological significance of this burden across climatic states. In the heat, moderate (>38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 and 180 min, respectively.     

Consideration of plant behaviour in optimal servo-compensator design

Where the most prevalent optimal servo-compensator formulations penalise the behaviour of an error system, this paper considers the problem of additionally penalising the actual states and inputs of the plant. Doing so has the advantage of enabling the penalty function to better resemble an economic cost. This is especially true of problems where control effort needs to be sensibly allocated across weakly redundant inputs or where one wishes to use penalties to soft-constrain certain states or inputs. It is shown that, although the resulting cost function grows unbounded as its horizon approaches infinity, it is possible to formulate an equivalent optimisation problem with a bounded cost. The resulting optimisation problem is similar to those in earlier studies but has an additional ‘correction term’ in the cost function, and a set of equality constraints that arise when there are redundant inputs. A numerical approach to solve the resulting optimisation problem is presented, followed by simulations on a micro–macro positioner that illustrate the benefits of the proposed servo-compensator design approach.     

Strong stability of the mono-tubular heat exchanger equation with output feedback

We investigate asymptotic behavior of the C₀-semigroup T(t) associated with the mono-tubular heat exchanger equation with output feedback by a perturbation method. It is shown that T(t) is bounded if a constraint is satisfied by the parameters and the spatial distribution function. Further, applying the Arendt-Batty-Lyubich-Vu theorem, a criterion is established to judge strong stability of T(t).     

活用RC特性实现对CMOS数字IC的输入保护

介绍了灵活利用RC的特性对CMOS数字IC的输入保护措施,并重点讨论了其应用电路及其参数的设计计算过程。此方法抑制噪声的效果非常好,可以广泛应用于理论及实践性教学、工程设计等方面。     

管壳式换热器传热强化技术进展

介绍了国内外传热强化技术研究的发展概况 ,简述了典型的强化传热元件开发、新型壳程结构设计及国内外推出的各种新型高效换热器的有关情况 ,指出了国内近期开发研究的发展方向。     

我国塑料热稳定剂生产现状与研究进展

介绍了国内塑料热稳定剂生产、市场和发展趋势。目前我国塑料热稳定剂无论是品种和产品质量等与国外先进水平仍有较大的差距，提出了我国热稳定剂的发展建议。