火花源原子发射光谱单次火花放电行为探讨

在火花源原子发射光谱中,光源的原子火花放电过程行为复杂,直接观测困难。为了研究原子在单次火花放电发光的行为,利用火花源原子发射光谱仪的时间解析功能和单次火花处理技术设计实验,获取不锈钢标准物质中铁、铝、硅、锰、磷、硫、碳等7个元素的原子在单次火花放电发光的光强随时间分布的时序曲线,通过对各个元素的单次火花光强随时间分布时序曲线的特征分析,得出了原子在单次火花激发过程中发光行为滞后于放电行为、不同元素的原子在同一激发条件下单次火花光强时序曲线的持续时间及发光的最高强度值的时间点存在差异的结论。这为降低火花源原子发射光谱仪的检出限、提高灵敏度以及避免元素间谱线干扰提供了新的途径,同时也为进一步研究火花放电过程中微观粒子的行为提供了新的途径。     

Quenching the thirst in dialysis patients

OBJECTIVE: To review the results of the operative treatment of posterior urethral injuries in children. PATIENTS AND METHODS: A total of 29 children (25 boys and two girls, age range 3-14 years) with injuries to the posterior urethra were admitted to this department over 14 years. Twenty-three patients presented immediately after trauma and six were referred after unsuccessful attempt(s) at surgical repair. RESULTS: Fourteen patients underwent suprapubic diversion and primary realignment over a catheter. Urethral continuity with normal urinary continence was achieved in seven of these patients. Four patients underwent a re-operation; urethral reconstruction was successful in these patients, but one patient remained incontinent. Primary realignment with anastomosis was performed in nine patients; the results were satisfactory in six. Urethral stricture developed in all of four patients who were managed with a suprapubic cystostomy alone; a staged repair using the transpubic approach was carried out in two of them and one improved. Partial urethral tears in two patients healed with urethral catheterization alone. CONCLUSION: Primary realignment of the urethra with anastomosis and suprapubic diversion resulted in the highest rate of success for normal urethral continuity. Urethral strictures or urinary incontinence were not major problems in this group. Therefore, we recommend this approach for the initial management of urethral injuries in childhood. Transpubic urethroplasties may be reserved for secondary repair.     

干法熄焦和稳定熄焦

对干法熄焦和稳定熄焦的技术特点和优势进行了分析比较。指出：干法熄焦回收占焦炉能耗的35％～40％的红焦显热是稳定熄焦所不具备的优势;干法熄焦改善焦炭质量是稳定熄焦所无法比拟的;干法熄焦在减少对环境污染方面显著优于稳定熄焦;各国能源情况和能源价格的差异决定了这些国家选择哪一种熄焦方式。     

甲板压淬热处理中淬火压床的设计

甲板的热处理技术是将甲板加热到一定温度后,对甲板进行喷水冷却处理.根据目前甲板热处理设备的现状分析了淬火压床系统的结构及工艺的缺陷,对淬火压床系统进行结构及加工工艺优化设计,使压头及框架结构趋于合理,保证了甲板淬火后平面度达到生产工艺要求,经过近几年的使用,取得了良好的效果.     

Q&P钢热处理工艺的开发进展

Q&P钢的工艺概念已提出了有些年了,它作为一种热处理工艺,生产的组织具有马氏体和富C的亚稳残余奥氏体.工艺包括:控制淬火形成部分的马氏体,然后热处理以使C从过饱和的马氏体中转移到残余奥氏体中.潜在的应用包括具有好的成型性和抗断裂的高强度钢.应用该工艺可生产薄板和厚板,以及用从长锻材生产热处理元件,甚至于铸铁.自2003年一直在实验室研究,早期的工作结果已有发表.近期的研究主要集中于机理方面的细节.国际范围的独立团队在此研究领域也有很多进展.     

Heat Transfer During Quenching by Plate Roller Quenching Machine

For plate quenching on a roller quenching machine, heat transfer process is investigated. According to the practical online experiment of plate center temperature, average heat transfer coefficient under different conditions and temperature fields are analyzed by numerical simulation. The results show that, at the water temperature of 15 ℃, the instantaneous maximum quenching cooling rate is 17.6 ℃/s for the plate of 50 mm in thickness in roller quenching process. In the temperature range of 400-850 ℃, the maximum is 12.1 ℃/s. With the plate surface temperature decreasing, surface heat transfer coefficient increases at first, and reaches the maximum value of about 15 000 W/(m~2·K), and then decreases. The calculated heat transfer coefficients are applied to analyze plate temperature field of different thicknesses, and the difference between the calculated and measured temperature is less than 5%.     

高性能淬火在最小的空间内获得最大的性能

近年来,对挤压淬火的的需求变的更加迫切。有三个主要因素促进了这些需求:更快的挤压速度,初出区域长度的限制以及因更快的淬火率而得到的型材性能的改进。这三个因素造成了对在最小空间内获得最大淬火性能的需求。本文研究分析了使淬火过程最优化的方法并详述了利用这些方法的淬火设计。     

芯棒淬火设备

芯棒是轧管必备的工具之一,有着比较复杂的生产工艺。描述了目前国内芯棒淬火的现状、介绍了天津赛瑞机器设备有限公司设计芯棒淬火设备的背景、设备的结构及工作原理。     

钢轨在线淬火系统设计

结合国内某钢厂新建钢轨在线淬火系统的设计过程,介绍了该钢轨在线淬火系统的布置形式、设备组成及工作原理,并对其中部分设备的结构特点进行了深入地分析和研究。采用一些新的设计思路,优化了布置形式及设备结构,为今后该类型系统的设计积累了经验。     

薄规格钢板淬火过程中的板形控制

在薄规格钢板的淬火过程中,板形变化是较难控制的方面之一。首先介绍了辊式淬火机的冷却过程及机理,再根据鲅鱼圈厚板部5500生产线的淬火实践生产,将该机理成功应用于淬火机设备的调整和校正,配以合理的淬火工艺参数,将薄规格HQ785T1钢板淬火后的板形不平度稳定在可控范围内,最后根据结果分析了影响板形变化的原因。     

Computer Prediction in Optimizing the Plasma Quenching of Locomotive Wheels

Computer software is developed for predicting the basic thermal characteristics in the plasma treatment of wheel rims for locomotives: the temperature, cooling rates, heat-flux density, and thickness of the martensitic layer at the wheel’s working surface. To verify the validity of this software, the results obtained are compared with thermometer readings and metallurgical data for the thickness of the martensitic layer. Two new features of the thermophysical model are the specification of the heat-transfer parameters in the plasma flare so as to ensure strengthening of the metal at the wheel rim by micromelting; and the ability to use the predicted temperatures and cooling rates in precision estimates of the martensitic-layer thickness. Estimates of the short-term thermal stress at the rim’s working surface show that compressive stress predominates. That is consistent with experimental data regarding the residual stress in steel samples after plasma treatment. If the proposed computer model is used in determining optimal conditions for the plasma quenching of locomotive wheels, the expenditures of time and material resources will be less than in in purely empirical selection of the operating conditions.     

日本放电等离子体烧结的现状

放电等离子烧结是通过粉末颗粒之间的等离子体放电,并对粉末加热加压进行烧结,制取高性能材料的一种新的粉末冶金技术.具有升温速度快、烧结时间短、组织结构可控、节能环保等鲜明特点.本文简介了日本近年来放电等离子烧结的现状,包括设备、模具、制备的材料.希望能对该领域的同行有参考意义.