Dealing with shift work: Physical fitness, temperature, and napping

This paper reviews the effects of generally controllable factors such as physical conditioning, ambient temperature, and amount of prior sleep in adjustment to night work periods and shift work. One can expect a 5-10% decline in capacity for work in nocturnal work periods as compared to daytime work periods. This decreased capacity would dissipate if workers maintained a consistent sleep-wake routine for 8-16 days after moving to a new shift. Proven means for accelerating this adaptation are currently not available. The ability to perform work also declines as the length of the work period increases but depending upon individual tasks. Physical conditioning improves mood and general well-being, but no strong evidence currently indicates that conditioning increases tolerance or adjustment to shift work.

Increased ambient temperature increases the stress of work, although studies do not address heat as a factor in adjustment to shift work. While lower nocturnal temperature would be assumed to reduce heat stress during night shifts, supporting data does not exist. Studies have not addressed the negative consequences of cold stress or of rotating from night to day shifts with added heat stress.

The proper use of short sleep periods either as preparation for or as a response to a shift change can ameliorate some effects of shift rotation. Data indicate that performance on 'graveyard' shifts can be maintained close to baseline levels following true prophylactic naps while performance may decline by up to 30% when such naps are not taken. While there is evidence that naps or even rest periods without sleep are beneficial in improving mood in normal young adults, these data do not apply to 'replacement' naps. Studies of interjected naps imply that such naps do reduce sleep debt but do not imply that such naps are more beneficial than longer sleep periods. Naps appear to be most advantageous when the accumulated sleep debt is least.     

基于切削温度分析的刀具磨损状态研究

为了解刀具在切削时的实际状况,课题组提出了基于切削温度的刀具状态实时监测的方案。[JP2]采用仿真与试验相结合相验证的方法,对刀具在新刀、早期磨损、严重磨损以及失效4种状态下的切削温度进行分析。通过试验采集刀具磨损及失效的温度信号数据,建立了基于最小模糊度的隶属度函数优化模型,用于诊断刀具加工过程中的磨损及失效状态。应用结果表明,该方法可以实现对刀具磨损及失效状态的实时监测,对提高机床的加工效率及加工精度具有重要意义。     

改性沥青在盐冻融循环条件下的性能研究

通过室内冻融循环试验,对SBS改性沥青和胶粉改性沥青在盐冻融循环前后的三大指标(针入度、软化点、延度)进行了测试。结果表明:两种沥青经盐冻融循环后,温度敏感性增加,高温性能及低温性能均有不同程度降低,且冰冻温度、融雪剂浓度、冻融循环次数对这两种沥青性能影响的程度不同,并通过对两种沥青材料盐冻融循环前后的各项指标对比,发现胶粉改性沥青抗盐冻循环性能优于SBS改性沥青。     

影响PCR仪温度控制精度的因素分析

简述了PCR仪器的基本原理,归纳阐述了影响PCR仪器温度控制精度的四种因素:加热器结构形式、温度传感与测量电路的形式、加热器的控制方式和温度控制算法。对每种因素都进行了比较研究。     

新型两用系363S在泸州育性表现的初步观察

对两用系新资源材料363S在泸州的育性表现进行了初步观察，结果表明：363S在泸州生态条件下，仍表现出明显的“低温诱导不育高温诱导可育”的特点。该不育系正常染色花粉百分率与其小穗育性表现不一致，以小穗育性为标准，在泸州7月中下旬为不育期，小穗不育度99．5％以上。诱导不育和可育的临界温度指标需进一步研究。     

哲里木盟4种主要农作物气候生产潜力变化及对比分析

分析了哲里木盟玉米、水稻、高梁、大豆４ 种主要作物近４５ 年光能、光温、气候生产潜力的变化,结果表明：生长季内（５ ～９ 月） 光能生产潜力在波动中有减小的趋势;温度升高,对４ 种作物光温生产潜力有不同程度的提高,其中对玉米、水稻、高粱的影响明显大于对大豆的影响;降水变化对生产潜力的影响远大于温度变化的影响,其中降水对玉米气候生产潜力的影响高于对高粱、大豆的影响。从生产潜力的大小及其变化来看,玉米和水稻是适应当地气候变化的优势作物,降水量不足是影响生产潜力发挥的主要限制因子     

试论“渗透温”概念的不存在——与高执棣先生商榷

本文从热力学开放体系不可能是绝热体系,开放相不可能是绝“热”相,半透膜必然是透热膜,化学平衡只可能在等温下建立,绝对熵与规定熵根本不同,不能无条件替代,等几个方面论证了所谓“渗透温概念”的不存在,并作了热力学的反证。     

Local likelihood smoothing of sample extremes

Trends in sample extremes are of interest in many contexts, an example being environmental statistics. Parametric models are often used to model trends in such data, but they may not be suitable for exploratory data analysis. This paper outlines a semiparametric approach to smoothing sample extremes, based on local polynomial fitting of the generalized extreme value distribution and related models. The uncertainty of fits is assessed by using resampling methods. The methods are applied to data on extreme temperatures and on record times for the women's 3000 m race.     

用补偿法测量人体深部温度

本文讨论了在人体表面测量深部体温的补偿测温方法。根据生物体导热方程,分析了人体组织的生理参数及测温探头的几何参数对测量结果的影响。据此制作了测温探头,进行了测温试验,得到了初步的试验结果。     

改进的PCR仪模糊PID温度控制算法

模糊控制算法的运算量和所占用内存与控制精度和动态响应之间总是一对矛盾体,本文就该应用性问题进行了研究。针对PCR仪温度控制系统,设计出一种按误差大小将其温控过程划分成三种控制域的方法,并给出了各控制域间带回滞的切换规则,在同样的精度要求下其控制算法所需要的内存和计算量分别是传统F-PID控制算法的0.4倍和0.25倍左右,即该控制算法在硬件条件不变情况下可以将精度提高F-PID控制算法的4倍左右。另外,系统的动态响应速度也将达到硬件所能达到的最大值且能很好地消除超调等动态误差。仿真试验证明了该方法的可行性。