一种求解涡旋电场的方法

变化磁场激发的电场称为涡旋电场.一般用麦克斯韦方程的方法来求解涡旋电场比较复杂,而且难于建立物理模型,容易转到纯数学化.本文类比静电场的叠加原理,阐述了一种用磁场元激发的电场叠加来求解涡旋电场.此方法简便、形像、突出了物理思想和物理模型,有利于教学和学生的接收.     

Disinfection of circulating water systems by ultraviolet light and halogenation

Continuous ultraviolet light (u.v.) and chemical disinfection of circulating water systems were evaluated. Direct comparisons of the biocidal effectiveness of u.v. light vs halogenation were tested with Legionella spp and Pseudomonas aeruginosa because of their association with the acquisition of overt clinical disease from water-containing appliances. Findings indicated that six species of Legionella and P. aeruginosa were killed by a moderate level of u.v. radiation. L. pneumophila and other bacteria in a circulating water system were effectively killed by a biocidal u.v. light. However, free chlorine levels needed to kill Legionella, Pseudomonas, and Flavobacterium within 1 min were found to be greater than 4 mg ml^?1. Data from a long-term field trial with u.v. light treatment of evaporative condenser water showed a significant reduction in numbers of bacteria. Ultraviolet disinfection of hospital hydrotherapy whirlpools confirmed the utility of this mode of disinfection under circumstances where chlorination may not be practical for medical reasons. These findings were confirmed during investigations of halogenated or u.v.-treated public hot tub/whirlpools. The effectiveness of routine chemical disinfection for controlling microbial flora in a cooling tower was also evaluated. The 2 month survey indicated that the numbers of bacteria, including Legionella, were not affected by two biocides that were used. The observations made during this investigation support the conclusion that u.v. light disinfection of water-containing systems may be an appropriate alternative or supplement to chemical biocides.     

湍流凝聚接触絮凝沉淀给水处理技术在原水预处理系统中的应用

通过对湍流凝聚接触絮凝沉淀给水处理技术机理的分析和工程实例的总结,详细介绍了该技术的技术理论、实际应用情况以及市场前景。     

Trihalomethane formation in whirlpool SPAs

In a survey of 25 whirlpool spas using halogen disinfectants, the only organohalide contaminant observed in the water and in the air at concentrations in excess of 1 μg l⁻¹ (water) and 1 μg m⁻³ (air) was the trihalomethane corresponding to the disinfectant used. The levels of trihalomethane observed in the water in thermal spas were comparable to levels reported for swimming pools. We conclude that the heat, agitation and aeration of the spas do not produce higher residual levels of trihalomethanes in the water and do not promote the formation of novel volatile organohalides. The concentration of trihalomethane in the water appeared to be related to the combination of high total dissolved solids and high disinfectant levels. The trihalomethane levels in the air though dependent on the concentration of trihalomethane in the water were modified by the variety of room sizes, ventilation rates, water surface areas and aeration rates associated with each individual spa.     

酒花与酒的探讨

在白酒中,酒花不仅与酒度有关,而且由于工艺、发酵设备、贮存容器、贮存时间、温度、加浆用水、微量成分等的不同,使得同一酒度酒酒花状况也有了差异,酒花的差异也一定程度标志着酒液的缔合程度的强弱,而缔合的强弱与酒体的绵柔程度也存在着一定的关系。     

异质材料铁-镍点焊熔合过程的研究

对异质材料铁-镍点焊在不同规范下熔合过程进行了试验研究，包括可焊性及规范参数的选择。分析了铁-镍点焊时出现的各种缺陷及消除或改善方法、熔核组织特点与规范的关系。对异质金属焊接时出现的旋流，指出了成因及消除方法。     

回旋沉淀槽优化措施探讨

回旋沉淀槽的优化措施主要有:根据麦汁的进口流量和速度,选择合适的高径比(H/D);根据泵入麦汁的时间,选择合适功率的麦汁泵,使回旋沉淀槽达到最佳沉淀效果.     

韶钢二轧厂旋流池挖孔桩帷幕施工技术

韶钢二轧厂旋流池直径为15 m,埋深达25.1m.由于位于隐伏岩溶地区,场地的工程地质和水文地质条件十分复杂,主体结构在施工过程中承受的侧向上压力和水压力巨大.为此,提出了由挖孔桩和砼圈梁组成的挖孔的桩帷幕施工技术.文中介绍了帷幕的构造组成、作用原理、荷载计算模型、设计与施工过程中的关键问题及决定帷幕可靠性的侧向位移的监测过程.施工实践表明,挖孔桩帷幕施工方法较常规的大开挖或沉井施工方法,节约投资33万元,工期提前30d,而且大大降低了施工难度.     

漩涡征在新生儿肠旋转不良诊断中的作用探讨

目的：分析漩涡征在诊断新生儿肠旋转不良有无合并中肠扭转的意义。方法：应用超声检查肠系膜上动脉和肠系膜上静脉的关系来明确有无漩涡征的存在。结果：所有患儿超声检查有漩涡征,于术证实为肠旋转不良伴有中肠扭转,39例患儿均存活,无严重术后并发症的发生,1例全中肠坏死,放弃治疗。结论：腹部超声检查漩涡征的仔在对先天性肠旋转不良有无合并中肠扭转有临床意义。     

旋流式复合雾化喷嘴雾化特性的试验研究

针对重质渣油燃烧现状,设计了一种旋转式复合雾化喷嘴结构,并对其雾化性能进行了实验研究,得到了平均雾滴粒径SMD随气液质量比ALR的变化规律,通过对比发现新型复合雾化喷嘴比单纯的气泡雾化喷嘴的雾滴粒径小,雾化锥角大,并对其原因进行了理论分析.