采用新型舒弹纤维开发羊毛加弹针织运动面料

介绍新型舒弹纤维Micro Stretch TM(简称MS)基本性能,如耐高温性、耐强酸强碱性、环保性等,并与普通氨纶进行对比。选用14.7 tex(40S)羊毛、锦纶混纺纱(混纺比为80∶20)与4.44 tex(40 D)MS舒弹丝交织编织添纱平针组织,在单面针织大圆机上开发一款新型羊毛加弹针织运动面料。详细阐述设备参数、织针排列、三角排列、注意事项等编织工艺,以及预定形、前处理、染色等染整工艺,并对成品各项性能进行测试。结果表明,该面料吸湿排湿性好,缩率及扭力、顶破强力和色牢度等均符合羊毛运动面料的要求,同时MS舒弹丝制成的针织面料无须高温坯定,尺寸稳定性好,产品品质优良,为高档毛针织产品的开发提供思路。     

超高导热陶瓷复频超声加工的基础试验研究

超高导热陶瓷基板作为新一代大规模集成电路的理想封装材料,其硬脆特性为加工带来了极大的困难.在工程陶瓷传统超声加工理论的基础上,针对因超声波发生器功率有限造成的传统单频超声加工振幅难以提高的问题,通过添加自由质量块引入低频大振幅振动的方法,实现了复频超声加工;针对因自由质量块的非正常碰撞造成复频超声加工单元频率不稳定的问...     

Self-tuned ultrasonic elliptical vibration cutting for high-efficient machining of micro-optics arrays on brittle materials

Ultrasonic elliptical vibration cutting is a very promising technique for the machining of brittle materials. However, its machining performance is currently limited by the ductile machining model and the machining strategy with a constant feed rate, leading to low machining efficiency. To overcome this defect, this paper presents a novel self-tuned ultrasonic elliptical vibration cutting (SUEVC) technique to achieve high-efficient ductile-regime machining of the micro-optics array on brittle materials. The proposed SUEVC includes a ductile-regime machining model and a tool path generation method. In SUEVC, the feed rate adaptively changes with respect to the local shape variation of the desired surface along the feeding direction to ensure both crack-free surface and high machining efficiency. Finally, two 1 × 3 spherical micro-optics arrays were successfully fabricated on single-crystal MgF₂ by SUEVC and the traditional machining strategy respectively. Results demonstrated that the SUEVC could enhance the machining efficiency by 30% relative to the traditional machining strategy, while maintaining similar surface roughness and a crack-free surface.     

Applications of digital signal processing methods in TOF calculation of ultrasonic gas flowmeter

Ultrasonic gas flowmeters (UGFM) are extensively used in petroleum, chemical, natural gas and other fields because of their distinctive measurement advantages. As the core technology of the UGFM, digital signal processing technology determines its measurement accuracy and stability. This paper systematically reviews the signal processing methods for measuring the TOF (time of flight) based on the principle of time difference method. According to the stability of the feature information extracted by different digital signal processing methods, the advantages and disadvantages of each method are analyzed. Aiming at the problems of serious energy attenuation, weak echo signal amplitude, and low signal-to-noise ratio (SNR) when ultrasonic signal propagate in the gas, different signal processing methods are evaluated and compared from the aspects of calculation accuracy, response speed, anti-interference ability and sensitivity to parameter changes. Finally, some improvement ideas and directions for further research are proposed according to the analysis results.     

基于Online LS-SVM的钢铁件渗碳层深度在线检测

为实现钢铁件渗碳层深度的在线电磁无损检测,提出在线最小二乘支持向量机(Online Least Square Support Vector Machine,Online LS-SVM)的建模方法.Online LS-SVM是以增量学习训练SVM,以减量学习减少样本数,实现小样本估计的训练方法.实验结果表明,Online LS-SVM不仅能实现钢铁件渗碳层深度的在线电磁无损检测,而且具有学习速度快、泛化性能好和对样本依赖程度低的优点.     

基于超声波的汽车防撞报警系统的设计

根据超声波测量距离系统,给出了汽车测距防撞报警系统的设计。该系统能在汽车行驶以及倒车过程中自动检测出汽车与最近障碍物之间的距离（或行车中的车距）井通过LED显示出来．当到达极限距离时,系统能发出声光报警．进而提醒司机以防撞车。试验研究结果表明．该系统具有一定的实用价值以及广阔的推广应用前景。     

Characteristics of chip generation by ultrasonic vibration cutting with extremely low cutting velocity

Recently, mirror-surface machining of brittle materials such as ferrite, glass, and optical plastics has become more important, as these materials are used in optical communications and precision devices. Non-ferrous metals such as aluminium and copper were readily turned with diamond tools, but as the need for both infra-red and reflective optics escalated, the need to machine brittle materials arose. In this paper, ultrasonic vibration cutting at 20 kHz at extremely low cutting velocity for the precision machining of brittle plastics used for optical lenses is suggested and tested. The mechanism of chip generation, and characteristics of surfaces in the ductile mode, machined by ultrasonic vibration cutting are investigated. As a result, when micro cutting by ultrasonic vibration, it was confirmed that the chips generated by ductile mode cutting are obtained at 1/40 of the critical cutting velocity of the ultrasonic vibration cutting system, which is an extremely low cutting velocity.     

基于单片机的冷却装置漏油检测系统的研制

本文介绍一种多通道循环冷却装置漏油检测系统。该系统由单片机应用电路和超声波乳化装置组成。在应用电路中设计了满足用户需要的多路模拟开关进行多点数据采集,并采用了点阵式液晶显示屏,具有较强的显示功能。本文着重于单片机应用系统的介绍。     

Fabrication and electrostatic actuation of thin diaphragms

In this paper, two kinds ofp ⁺ diaphragms are fabricated. One is flat, and the other is corrugated to release the residual stress resulted from the diffusion process. The two diaphragms are electrostatically actuated, and the center deflections of the diaphragms are measured for various frequencies. The static deflections of the flat diaphragm and the corrugated one estimated from the test results are compared with the calculated static deflections under residual tensile stress. The experimental result and the calculated result agree in the case of the flat diaphragm with a reasonable residual stress, but it is not true for the corrugated diaphragm. In the calculation, it is estimated that the corrugated diaphragm deflects more than the flat one. In the experiment, however, the corrugated diaphragm deflects less than the flat one.     

植物提取物中有机氯农残检测的前处理研究

本研究应用超声波提取、GPC凝胶净化、气相色谱ECD检测器定量测定植物提取物中多种有机氯农药五氯苯胺、腐霉利、五氯苯、四氯硝基苯、四氯苯胺、六六六、滴滴涕、六氯苯、五氯硝基苯、甲基五氯苯基硫醚、狄氏剂、灭菌丹、敌稗等残留,方法检出限0.0001～0.005mg/kg,回收率80%～95%之间。