数字式温度传感器在冰箱检测系统中的应用

本文介绍了数字式温度传感器的工作原理、性能特征以及如何在冰箱检测系统中引入单总线技术,使用数字式温度传感器更好的实现温度的采集。     

钢筋混凝土连续箱梁温度收缩应力计算

提出了钢筋混凝土连续箱梁温度收缩应力计算的一种模式,并对这种计算模式作了详细阐述,为工程技术人员采取适当工艺和养护方法来控制混凝土早期裂缝的发生提供了一种依据.     

The induction of secondary seed dormancy by oxygen deficiency in a barnyard grassEchinochloa crus-galli

At 25°C, secondary dormancy was induced in seeds ofE. crus-galli exposed for 100 days to oxygen deficiency. By contrast, hypoxia did not induce dormancy at 15°C or prevent dormancy termination at 7°C. Secondary dormancy was terminated after 2 months stratification at 7°C. Oxygen deficiency may increase the proportion of dormant seeds in the soil, and affect the dynamics of the barnyard-grass soil seed bank.We thank Miss Jitka Králová for her excellent technical assistance.     

Biosynthesis of 1-aminocyclopropanecarboxylic acid: Steric course of the reaction at the C-4 position

Summary Under the action of the appropriate synthase from ripe tomatoes a 11 mixture of (3S, 4R)-[3,4-²H₂] and (3R, 4S)-[3,4-²H₂]-(2S)-adenosylmethionine is transformed into a 11 mixture of the two meso forms of [²H₂]-1-aminocyclopropanecarboxylic acid, a result which proves the operation of an inversion mechanism and which is consistent with direct nucleophilic displacement of the leaving group in the substrate.     

Internal interactions within the human circadian system: the masking effect

Summary In the realm of human circadian rhythms, the masking effect is defined as the change in the course of deep body temperature induced by changes in the degree of physical activity, or by the alteration between sleep and wake. This effect is particularly obvious during internal desynchronization where the rhythms of deep body temperature, and the sleep-wake sleep-wake sleep cycle — i.e. one of the masking factors — run with different periods.Every sleep onset is accompanied by a rapid drop, and wake onset by a rapid rise in deep body temperature, each one with an overshoot of about 50% of the steady state variations. When rhythms are calculated, with the dominant temperature period as the screening period, exclusively from data obtained during sleep episodes, on the one hand, and from those obtained exclusively during wake, on the other, two average cycles emerge: the sleep temperature curve and the wake temperature curve. Both run in parallel but are separated by the masking effcct. As derived from many experiments, the mean masking effect amounts to 0.28±0.06°C. The masking effect also depends to some extent on the phase of the temperature rhtthm; it is larger than average around the temperature maximum and during the descending phase of the temperature cycle, where the alertness commonly is highest and the probability to sleep, in general, and the REM sleep propensity, in particular, are smaller than average. This also can be interpreted to indicate that the sleep temperature curve is phase advanced relative to the wake temperature curve; this, on the average, by 0.9±0.3 h.If the individually determined amount of masking is added to the temperature data obtained during sleep, or substracted from the temperature data obtained during wake, a temperature curve emerges that can be though of as being purified of the masking effect. Analyses of this artificial curve allow estimation of that part of the internal interactions uninfluenced by the masking effect. On the average, about half of the amount of interaction between the rhythm of sleep-wake and that of deep body temperature is explained by the masking effect, whereas the other half is oscillatory interaction. Both types of interaction are inherent and inseparable parts of the circadian clock mechanism, as can be deduced from model considerations.     

Photoperiodic summation is temperature-dependent inPyrrhocoris apterus (L.) (Heteroptera)

Summary InPyrrhocoris apterus, a low temperature, 15°C, prevented the termination of diapause by long days and, unexpectedly, also the induction of diapause by short days. Both responses were enabled at a higher temperature, 26°C. In contrast to current concepts, it was proved that the summation of photoperiodic signals was temperature-dependent, since the morphogenetic development was prevented by starvation.     

浅论温室效应及其灾害和对策

本文概略综述了近年来世界争论的“地球危机”问题。由于人类的活动,大气中二氧化碳等增加,气候恶化,地球升温,导致一系列重大自然灾害,严重地威协着人类。本文特对地震灾害进行了分析,温室效应对地球表面的升温,虽不至于直接影响到地震的孕育和发生,但是观测事实表明,环境因子太阳活动和气象与地震之间存在某种联系,对地震的发生常常起有调制和触发的作用,大气变化和太阳活动会影响到地震发生的频度和强度。为配合“国际减灾十年”活动,本文亦讨论了对策问题。     

Hypothalamic histamine modulates adaptive behavior of rats at high environmental temperature

Summary Histamine content in the rat hypothalamus was lower at 4°C and higher at 31°C compared to that at 21°C. Pretreatment with -fluoromethylhistidine, a suicide inhibitor of histidine decarboxylase, attenuated both the increased level of hypothalamic histamine and rat adaptive behavior at 31°C. Increase of histamine content in the hypothalamus appears to be an important factor contributing to rat adaptive behavior to high environmental temperature.     

温度对半导体激光器性能参数的影响

本文主要研究了温度对激光器各参数的影响，主要包括温度与阈值电流密度的关系，温度对输出光功率的影响，温度对微分量子效率的影响，并且总结了一些温度和激光器结构设计之间的关系。     

时间相关的含缺陷材料的流变破坏理论

含缺陷物体的与时间相关的失效过程是一个热力学开放的，远离平衡态的系统，失效过程中发生耗散结构的自组织现象，不同尺度上耗散结构的自相似性可供从微观过度到细观和宏观，基于缺陷演化过程国局域温度场和热磁效应的实验研究，从统一的宏、细、微观层次体系出发。研究了与时间相关的缺陷体的失效过程，结果表明。这个失效过程并非纯力学过程，其中的热力耦合和热磁效应不容忽略。