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1.
孙福成  宋健  江以萍  朱峰 《声学技术》1994,13(4):162-164
B4矩形超声换能器方阵的研究孙福成,宋健,江以萍,朱峰(上海交通大学上海·200030)在我们研制的超声加热治癌系统中为了增大加热面积和增大加热深度,我们选用9片方形压电晶片组成一个方阵(3×3),每片大小为3.0cm×3.0cm,这样可以方便地对不...  相似文献   

2.
聚焦超声热疗二维稳态温度场模拟   总被引:1,自引:0,他引:1  
本文运用差分法求解了聚焦超声加热的二维稳态温度场,比较了声场与不曙度场的特征,分析了耦合层厚度与治疗区大小,位置的关系。  相似文献   

3.
G1700W级超声功率计的研制寿文德,王一抗,陶海东(上海交通大学仪器工程系上海·200030)对肿瘤的热疗已成为治疗晚期大肿瘤的重要辅助手段。超声加热治癌法具有加热深度大,便于聚焦且疗效较好的优点。为适应超声热疗的需要;测定大面积大功率发射换能器阵...  相似文献   

4.
诊断超声剂量对人胚绒毛细胞作用的实验研究   总被引:1,自引:1,他引:0       下载免费PDF全文
长期以来人们一直在为攻克癌症作不懈的努力,超声肿瘤热疗作为肿瘤热疗的一种手段,从70年代才开始发展起来。相当长的一段时期内,超声热疗主要以温热疗法为主,温热疗法要求把肿瘤的温度加热在42~45℃范围内,而相应的体内测温技术还未成熟,因此超声温热疗法一直进展缓慢。直到80年代末90年代初,高强度聚焦超声(highintesityfocusedultrasoundHIFU)的兴起,才再次引起了人们对超声热疗的关注,HI-FU除了具有超声加热对人体无附加损害、穿透力强、对脂肪组织不选择加温等优点外,它…  相似文献   

5.
腔内高强度聚焦超声肿瘤治疗的实验研究   总被引:3,自引:2,他引:1  
本文作者对于利用高强度聚焦超声(HIFU)进行肿瘤腔内治疗作了许多理论计算和试验工作,比较了两种换能器的聚焦特性并研制了一种既能监视又能治疗的高强度聚焦超声换能器,利用此换能器对人工模及活体肿瘤进行了一系列加热实验,验证了高强度聚焦超声治疗肿瘤的可行性。为加热治疗机的开发提供了依据。  相似文献   

6.
本文介绍了一种专为卷绕镀机而研制的冻加热系统。它是在于制冷技术的基本原理,从镀膜主辊的冷负荷计算出发,论述了该系统有关的设计计算方法,从而提高了该系统设计的可靠性,准确性及经济性,增强了设计的科学性与实用性,为冷冻加热系统的优化设计作了有益的探索。  相似文献   

7.
由于油田水质高矿化度特性,加热装置严重结垢现象较为普遍,造成系统热效率的降低、加热设备损坏频率加大。通过近几年加热炉节能技术的筛选与应用,萨南油田近7年中共80台加热炉应用超声波防垢技术,实现综合热系统效率提升8.32%,实现年节气279万立方米/年,三年加热炉大修频率由9.38%降低至1.61%,每年减少基建维护投资143万元。通过节能、防垢技术的多年应用与监测,不仅实现了加热系统高效节能,同时大幅度降低了设备损坏频率,实现了保安全、促节能、降投资的目标,为油田加热装置安全运行、低耗高效提出切实可行的技术措施。  相似文献   

8.
为有效降低真空冷冻干燥设备运行能耗,在两套SZDG75型大型食品真空冷冻干燥设备上,分别采用了水作为载热流体的加热系统和二次蒸汽作为载热流体的加热系统,进行了冻干加工实际生产应用对比实验。实验结果表明,当进行小葱冻干加工时,在相同的实验条件下采用二次蒸汽加热系统的冻干设备的加工时间,比采用水加热系统的冻干设备缩短了1个小时,设备运行电耗降低11%,综合效果明显。  相似文献   

9.
广州地区热泵辅助太阳能热水系统性能分析   总被引:1,自引:0,他引:1  
基于广州市典型气象年参数,计算了广州地区太阳能热水系统集热器的适用面积,结果比通常太阳能厂商所推荐的面积值要大得多。按平均太阳能热水器面积值计算有14.5%的天数不能保障加热至所需温度,需较多的补充加热量。采用空气源热泵补充加热,随太阳能热水器加热面积减小,需补充加热耗电量增加。采用太阳能和空气源热泵热水系统的节电率相对直接电加热或水源辅助热泵补充加热的系统优势增大。  相似文献   

10.
对河南中美铝业有限公司——溶出车间在管道化溶出装置中,熔盐加热系统是安全风险较高的区域,本文结合一些实际发生的事件,对熔盐加热系统和以熔盐加热的溶出套管进行了分析,并提出了一些安全防范措施。  相似文献   

11.
Over recent decades, industry has used more and more frequently composite laminates. If many Non-Destructive Testing (NDT) methods have already been developed to test such structures, detecting defects in polymer matrix laminates remains difficult. After a short overview of the main existing NDT methods, this paper focuses on two techniques which appear to be very promising: thermosonics and infra-red (IR) thermography. For thermosonics tests, an ultrasonic horn mechanically loads the sample, while an IR camera records the defect heating. For thermography tests, the heating is due to an optical wave. If minor improvements on the test device are presented for thermosonics tests, IR thermography tests are achieved with a CO2 laser as excitation source, which is a very innovative approach. This paper provides many experimental results obtained from an aeronautical carbon-epoxy plate with a central delamination. It is shown that both methods are very suitable for detecting such a defect, even if each method has its own advantages. Finally, some improvements to further optimize the thermography tests are proposed in conclusion.  相似文献   

12.
空气源热泵因性能稳定、使用方便等特点在房间供暖与空调等领域得到广泛应用,冬季室外换热器表面结霜和除霜是影响其系统性能的主要因素。本文概括了空气源热泵系统的结霜条件、无霜化以及各类热力与非热力除霜方法,重点阐述了采用相变蓄热装置的各种热泵系统及除霜方法,对研究报导中应用的相变材料、蓄热换热器结构进行综述。最后对实现空气源热泵产品的无霜化或除霜高效化和持续供热的研究方向进行展望:可靠的吸附材料及其再生方法研发是通过干燥方法破坏除霜条件的技术需求;高压电场和超声波除霜方法需进一步完善,提高稳定性和经济性;蓄热除霜有很大的市场潜力,但需优化系统及蓄热换热器设计,并深入相变材料的研究。  相似文献   

13.
In this work, the effects of ultrasonic field on the Pb‐Sn alloys during heating process have been discussed using electrical resistivity and thermal curves. The semi‐solid and liquid alloy have different resistivity responses to ultrasonic irradiation, due to ultrasound irradiation only available to liquid phase. Sensitive structural change by ultrasound can be only found in the liquid state, according to the resistivity drop and thermal curves. It might be due to the low volume fraction of liquid phase at initial stage and the fast solid‐to‐liquid transitions at the final stage. Ultrasound can also trigger the nucleation and growth of liquid phase, through driving the melting of solid phase at solid/liquid interface and transferring into the liquid phase. The concerned mechanisms have been discussed in detail.  相似文献   

14.
The closure process for packaging is a key process. It ensures the protective function of packaging and assures the packaged goods a long life. In this context, efficient and reliable sealing processes are essential for the production of sustainable packages. In this paper, several characteristics of the ultrasonic sealing process will be discussed and accompanied by experimental results. The introduction provides an insight into the ultrasonic sealing process, its heating mechanisms and the process steps. A comparison is made with conduction sealing. Furthermore, basic principles of heating and energy dissipation are related to the influences of the sealing parameters on the seam strength. The experimental studies were carried out on typical packaging films, such as polyamide‐polyethylene laminates. The seam strength in ultrasonic sealing is compared with that in conductive sealing. A lower seam strength was found for ultrasonic sealing in all the tested films. Furthermore, the sealing behaviour of the packaging films contaminated with different kinds of foods was analysed for both sealing methods. Although the ultrasonic sealing method has marginal advantages for bulk materials such as wheat flour, conduction sealing was shown to be better for other products. A comparison of the energy consumption during the ultrasonic and conduction sealing verified the advantages of ultrasonic sealing. In particular for thick packaging films, the amount of energy required for bonding is significantly lower than for conduction sealing. In summary, this paper provides a survey of the characteristics of the ultrasonic sealing method in packaging applications – its advantages and limitations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
超声波热量表是精确计量供热过程中热能消耗的一种计量仪表。本文通过对超声波热量表工作原理的分析,指出影响超声波热量表性能的核心因素为超声波传感器。通过对超声波传感器主要参数的详细分析,为计量校准人员准确、高效的完成超声波热量的计量校准工作提供帮助,同时给超声波热量表生产企业提出相应的建议。  相似文献   

16.
Composite materials are being increasingly used in high-tech industries, such as aerospace, automotive manufacture and building inspection. Thermal nondestructive testing (TNDT) has become an accepted method for composite inspection. However, the majority of investigations have dealt with flat or slightly-curved composite components with a thickness of up to 5 mm. Particular studies have been devoted either to NDT modeling with an emphasis on some theoretical issues, or they have been based exclusively on experimental results. There has been some recent interest in the use of composite materials in the nuclear industry. Some critical parts, including centrifuge components, have been made of carbon fiber reinforced polymer (CFRP) composites. The working conditions in a centrifuge include radioactivity and high rotational speed, and the composites used in centrifuges must have very uniform thermal properties and must be free of defects.This paper describes a complex approach to the TNDT of cylindrical parts made of CFRP by starting from thermal properties measurement, theoretical modeling and preliminary experiments, and finishing with the technical requirements for the development of practical equipment capable of operating in both laboratory and industrial conditions.The objects tested were CFRP cylinders with a diameter of 150 mm and a wall thickness of 4–6 mm, and they contained some artificial defects of varying size and depth. Both one- and two-sided test procedures have been analyzed for spot, line and uniform heating. Ultrasonic excitation has also been used as an alternative stimulation technique.In a one-sided test, the depth detection limit has been about 4 mm. Similar results have been observed in the case of ultrasonic stimulation, but the practical implementation of ultrasonic IR thermography to the inspection of cylindrical parts requires further exploration.In a two-sided test, even fairly mild heating resulted in the reliable detection of all defects independent of their size and depth.In all test cases, the highest signal-to-noise ratio occurred after applying the technique of principal component analysis.  相似文献   

17.
High-resolution ultrasonic spectroscopy was applied for real-time monitoring of the heat-induced denaturation and aggregation processes in aqueous solutions of β-lactoglobulin. The temperature profiles for the ultrasonic velocity and attenuation in the frequency range from 4MHz to 16MHz were measured during heating and cooling cycles, 35°C to 120°C to 35°C, with different heating and cooling rates. Two processes were identified in the heating profiles: transition to the molten globular state followed by formation of protein aggregates. Both processes are accompanied by a decrease in the ultrasonic velocity and an increase in compressibility. The ultrasonic attenuation did not show a significant change during the transition to the molten globule but increased significantly during aggregation. The diameter of the aggregates (calculated from ultrasonic attenuation) was of the order of 100nm and depended on the pH and the heating rate. Variation of pH from 6.0 to 7.5 had a pronounced effect on the size of protein aggregates. Some effect of pH on the intrinsic properties of aggregates was also detected.  相似文献   

18.
基于超声波在多层介质中的传播规律,探讨超声波技术检测加热管内表面结焦层的可行性。研究结果表明:超声波技术无损评价炉管内壁结焦层厚度是可行的;超声回波信号的幅度、周期性以及波形的畸变程度可作为结焦层厚度变化的表征指标;无焦区,回波清晰,周期性较好,幅度较高;薄焦区,回波幅度减少,周期性较好,回波略有畸变;厚焦区,回波幅度明显降低,畸变严重。  相似文献   

19.
基于传热介质的蒸汽加热凹印机能耗测试方法研究   总被引:2,自引:2,他引:0  
金琳  李艳  王仪明  刘淼  刘宁 《包装工程》2015,36(5):105-111
目的提出蒸汽加热方式的凹版印刷机在印刷过程中能耗的测试方法。方法首先采用电平衡法建立凹印机消耗电能的数学模型,而后采用风量计量法和传热介质计量法分别建立蒸汽加热方式的凹印机消耗热能的数学模型,最后借助红外测温仪、超声波液体流量计和功率计对印刷厂中的多台凹印机进行现场测试。结果电阻丝和其他电机消耗的功率符合实际要求,通过测量的平均有功功率和功率因数反推得到的额定功率,与电机名牌示数上的额定功率十分接近,传热介质计量法和风量计量法分别求得的热能消耗值相接近。结论验证了蒸汽加热方式凹版印刷能耗测试方法的正确性和可行性,并较准确地测出了印刷过程中消耗的能量。  相似文献   

20.
影响复合材料性能很重要的一个因素是复合材料基体和增强体之间所形成的界面层状态,浸润性是影响界面的重要因素。本文从渗透力、吸附、低粘度、加热、真空、超声方面,探讨改善复合材料浸润性的技术和方法。  相似文献   

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