载货汽车制动毂自动冷却装置实现原理分析

 通过对载货汽车制动的基本结构和原理的分析,结合云南山区道路坡大弯多,制动负荷大的特点,提出了载货汽车制动冷却自动控制装置的方案,并对该自动控制装置中的传感器、放大器、A/D转换器、D/A转换器、执行元件进行了分析。     

土壤水分含量测定方法研究

土壤水分含量是影响作物生长的重要因素,也是判断农业环境干旱的重要指标.由农业生产实际情况可知,作物生长的水资源条件最终是反映在土壤水分条件的好坏上.因此,需要充分了解土壤水分的各种时间尺度的演变特征和空间的立体分布,而更为重要的是了解作物主要生产期和关键需水期的土壤水分状况.目前,已有数十种土壤含水量快速测量方法.为此,介绍了近几十年来国内外关于土壤水分含量的各种测定方法,通过查阅大量资料对原理及其优缺点进行了分析与比较,并对其前景进行了展望.其中,有些测量方法存在着许多缺点和弊端,所以寻求一种精度高、可靠性强、成本低、无破坏以及快速的土壤含水量测定技术的工作迫在眉睫.     

PJK-200平板式节能烤烟房研究和设计

该烤房解决了我国多数烟区几十年来使用的“火龙”式烤房的几个突出问题。采用平板散热、立式火炉、型煤燃烧等措施后,使供热系统效率提高20％,排烟温度降低100℃,脱水耗热量降到4300kJ/kg,为国内提供了一个耗能水平低的新型炕种。     

液压检测中流量测量的探讨

该文阐述了国内外流量检测的现状，介绍了一种新颖、独特的流量测试装置，并对该电感插入式流量传感器的原理、电路、标定方法和ＹＣ－Ａ型液压测试仪的流量测定电路进行了综合分析。     

联合收割机谷物流量测试装置和性能研究

随着现代化农场管理和农业生产的需要,提出了在作业中的联合收割机上监测谷物流量的要求。本文阐述了一种应用红外光电传感器和微电子技术在联合收割机谷粒升运器上进行谷物流量监测的原理和方法,分析了试验数据,进一步探讨了开发适合联合收割机使用的谷物流量仪的可行性。     

Comparison of water manometry to 2 commercial electronic pressure monitors for central venous pressure measurement in horses

Background: Central venous pressure (CVP) customarily has been measured in veterinary patients with water manometry. However, many institutions are now using stallside electronic monitors in both anesthesia and intensive care units for many aspects of patient monitoring. Hypothesis: Electronic stall side monitoring devices will agree with water manometry for measurement of CVP in horses. Animals: Ten healthy adult horses from the university research herd. Methods: Central venous catheters were placed routinely, and measurements were obtained in triplicate with each of the 3 methods every 12 hours for 3 days. Data were analyzed by a Lin concordance correlation coefficient and modified Bland‐Altman limits of agreement, with all devices compared pairwise. Results: Compared with water manometry, agreement (bias) of the Passport was ?1.94 cmH₂O (95% limits of agreement, ?8.54 to 4.66 cmH₂O) and of the Medtronic was ?1.83 cmH₂O (95% limits of agreement, ?8.60 to 4.94 cmH₂O). When compared with the Passport, agreement of the data obtained with the Medtronic was 0.27 cmH₂O (95% limits of agreement, ?4.39 to 4.93 cmH₂O). Conclusions and Clinical Importance: These data show that both electronic monitors systematically provide measurements that are approximately 2 cmH₂O lower than water manometry, but differences between the 2 electronic devices are small enough (< 0.5 cmH₂O) to be considered clinically unimportant. This discrepancy should be taken into account when interpreting data obtained with these monitoring devices.     

LXH-CY型质量流量计的研制

介绍了一种主要用于油田单井出油初步计量的三相质量流量计，包括其测量原理、结构、功能特点和技术指标等。     

变频器谐波的产生、危害及抑制

变频器的工作原理决定了它会产生高次谐波,这样会对设备及附近的仪器仪表产生影响。本文简单介绍了高次谐波产生的机理、危害及有效抑制干扰的方法。