对数平均温差中试差法计算

传热操作型计算中,常遇到对数平均温差的试差计算以确定流体的某一个温度。教材中没有讲解如何计算,学生普遍反映不知从哪儿开始进行试差。该研究从试差法的计算步骤和试差范围的确定方法来讲解计算技巧,以便学生掌握和供同行参考。     

随机对照试验论文英文摘要的质量亟待提高

参照《期刊与学术会议摘要中报告随机对照试验的CONSORT声明》拟定的报告清单,审核了国内4种重要期刊2005—2008年随机对照试验(RCT)英文摘要的报道质量。利用PubMed共查到108篇RCT摘要。经审核报道最好的项目是目的和结论,试验状态、分组例数和干预次之。对RCT执行质量的关键信息描述最差:盲法、随机分组方法和数据分析例数的报道分别为0、1.9%和6.5%。结果表明,RCT摘要报道普遍不完整。建议医学期刊采纳《摘要CONSORT》,制订可行的模板以提高RCT摘要报道的完整性和有效性。     

致人而不致于人——"武术与兵家"研究之三

掌握主动而摆脱被动,"致人而不致于人",对于所有形式的对抗斗争来说,都是至关重要的.古代兵家与传统武术家们不但对此达成了共识,而且,略为深入,我们还会发现,两者在具体的实践操作中的基本思路,也是大致相同的.     

The impact of breathing on HRV measurements: Implications for the longitudinal follow-up of athletes

Abstract

The purpose of the present work was to compare daily variations of heart rate variability (HRV) parameters between controlled breathing (CB) and spontaneous breathing (SB) sessions during a longitudinal follow-up of athletes. HRV measurements were performed daily on 10 healthy male runners for 21 consecutive days. The signals were recorded during two successive randomised 5-minutes sessions. One session was performed in CB and the other in SB. The results showed significant differences between the two respiration methods in the temporal, nonlinear and frequency domains. However, significant correlations were observed between CB and SB (higher than 0.70 for RMSSD and SD1), demonstrating that during a longitudinal follow-up, these markers provide the same HRV variations regardless of breathing pattern. By contrast, independent day-to-day variations were observed with HF and LF/HF frequency markers, indicating no significant relationship between SB and CB data over time. Therefore, we consider that SB and CB may be used for HRV longitudinal follow-ups only for temporal and nonlinear markers. Indeed, the same daily increases and decreases were observed whatever the breathing method employed. Conversely, frequency markers did not provide the same variations between SB and CB and we propose that these indicators are not reliable enough to be used for day-to-day HRV monitoring.     

法律视角下农地使用权证券化流转的必要性与可行性

证券化是一种以证券为纽带的农地使用权流转机制,对于保护农民土地增量收益与促进对农投资、繁荣农村金融市场有重要价值。同时,现有的权利基础、运行机制与载体为农地使用权证券化流转提供了规则要件;土地利用分区管制与土地发展权制度为农地使用权证券化流转与耕地保护之国策之间提供了协调与控规机制;农地使用权证券化本身有助于解决农民因失地导致的社会保障问题。     

辽宁交通水泥厂建筑设备基础沉降观测变形分析

文章对辽宁交通水泥厂建厂的基础进行沉降观测。观测目的是监测建筑物基础在施工期间受地质条件影响,设备荷载等影响是否产生沉降,是否影响设备生产和运营。同时对变形监测网的布网方案,布网精度,使用观测仪器,测量方法,精度要求,数据处理进行分析和论证。为保证辽宁交通水泥厂的正常基础施工建设起到安全监测作用。     

VOLVO L180E柴油机的电控燃油喷射系统分析

在介绍L180E装载机柴油电控燃油系统基本组成的基础上,分析该系统的工作原理和特点。     

应用于低中频Zigbee收发机的5-GHz恒定带宽频率综合器（英文）

设计并实现了一个应用于ZigBee收发机的全集成整数N频率综合器.频率综合器中采用了稳定环路带宽技术,使频率综合器的环路带宽在压控振荡器（VCO）的整个输出频率范围内恒定不变,从而维持了频率综合器的相位噪声最优值与环路稳定性.频率综合器的同相与正交信号（IQ）由VCO输出端的除2分频器产生.该频率综合器采用0.18μm RF CMOS工艺技术制造,芯片面积约1.7mm2.频率综合器采用在晶圆测试的方式进行了测试.在1.8V电源电压下,频率综合器不包括输出缓冲所消耗的总功率为28.8mW.频率综合器在2.405GHz载波1及3MHz频偏处测得相位噪声分别为-110和-122dBc/Hz.频率综合器在2MHz频偏处测得的参考杂散为-48.2dBc.测得的建立时间约为160μs.     

审判利用的过程分析：一种法社会学的视角

通过界定权利意识和诉讼意识的概念,指出纠纷发生后,当事人为谋求纠纷的实质性解决,倾向于援引规范作为他们说服的根据,从而使纠纷衍化权利纠纷,权利纠纷使当事人具备权利意识。此后当事人经过对成本的权衡,并得到国家诉讼政策的允许,选择进行诉讼,将权利意识转化为诉讼意识。诉讼意识范畴小于权利意识范畴,具有权利意识的纠纷当事者并不必然选择诉讼作为其权利实现的手段。因此,国家所要做的就是为当事人之间适于通过审判解决的纠纷提供便利,使其接近司法,接近正义。     

Making formative assessment discernable to pre‐service teachers of science

The purpose of this pragmatic action research study was to explore our re‐conceptualization efforts in preparing pre‐service teachers to guide the inquiry process with formative assessment and subsequently use the understandings to improve our teacher preparation program. The process was guided by two questions: to what extent did course re‐conceptualization efforts lead to a more informed understanding of formative assessment by pre‐service teachers and did strategies enacted in the re‐conceptualized methods course foster or hinder pre‐service teachers' understanding of formative assessment? Data from this study support the following findings: (1) a substantial pre‐ to post‐methods course difference was realized in the pre‐service teachers' understanding of formative assessment; (2) explicit and contextualized approaches to formative assessment in the methods course led to increased understandings by pre‐service teachers; (3) an implicit approach led to improvements in course structure but did not foster pre‐service teachers' understanding of the reflexive nature of formative assessment; and (4) a field‐based case study on elementary science teaching both hindered and fostered our efforts with formative assessment. This study yields implications for pre‐service teacher education on formative assessment. To foster pre‐service teachers' knowledge and skills, we suggest explicit instruction on formative assessment combined with case studies, field experiences, and ongoing reflection. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 402–421, 2010