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Studying creation of bulk elementary excitation by heaters in superfluid helium-II at low temperatures 被引量:1
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作者 ZAKHARENKO A. A. 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第7期1065-1076,共12页
In this paper, the obtained experimental results concerning creation of bulk elementary excitations (BEEs) in isotopically pure liquid ^4He at low temperatures -60 mK are discussed. Positive rotons' (R^+-rotons)... In this paper, the obtained experimental results concerning creation of bulk elementary excitations (BEEs) in isotopically pure liquid ^4He at low temperatures -60 mK are discussed. Positive rotons' (R^+-rotons) creation by a pulsed heater was studied. Signals were recorded for the following quantum processes: quantum evaporation of ^4He-atoms from the free liquid-helium surface by the BEEs of the liquid helium-Ⅱ, and BEEs reflection from the free surface back into the bulk liquid. Typical signals are shown, and ratios of signal amplitudes are evaluated. For long heater pulses from 5 to 10 μs, appearance of the second atomic cloud consisting of evaporated ^4He-atoms was observed in addition to the first atomic cloud. It is thought that the first atomic cloud of the evaporated helium atoms consists of very fast ^4He-atoms with energies ~35 K evaporated by positive rotons with the special energies ~17 K (~2ER~2×8.6 K with ER representing the roton minimum energy) corresponding to the third non-dispersive Zakharenko wave. The second cloud of slower ^4He-atoms was created by surface elementary excitations (SEEs or ripplons) possessing the special energies ~7.15 K representing the binding energy. It was assumed that such SEEs can be created by phonons incoming to the liquid surface with special energies ~6.2 K corresponding to the first non-dispersive Zakharenko wave which can interact at the liquid surface with the same phonons already reflected from the surface for long heater pulses. Also, some pulsed-heater characteristics were studied in order to better understand the features of such heaters in low temperature experiments. 展开更多
关键词 Superfluid helium-ii Bulk elementary excitations (BEEs) Low temperatures Cooper pairing phenomenon Non-dispersive Zakharenko waves
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超流氦中喷射流流场的PIV可视化观察 被引量:2
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作者 金滔 FUZIER Sylvie VAN SCIVER Steven 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2010年第3期473-475,562,共4页
利用粒子成像测速仪(PIV)对射入到超流氦液浴中的喷射流的初始发展阶段进行观察,主要考察了流型和流场分布状况,旨在分析通过喷射流来实现的示踪粒子投放过程的实际效果及其对测量精度的影响情况.超流氦液浴温度为1.8K,示踪粒子为1.7μ... 利用粒子成像测速仪(PIV)对射入到超流氦液浴中的喷射流的初始发展阶段进行观察,主要考察了流型和流场分布状况,旨在分析通过喷射流来实现的示踪粒子投放过程的实际效果及其对测量精度的影响情况.超流氦液浴温度为1.8K,示踪粒子为1.7μm直径的复合物粒子,高速相机拍摄的相邻照片间隔时间为3ms.实验中观察到的喷射流具有一抛物线形状的流型,与正常流体中观察到的喷射流具有一定的相似性.速度场分析结果也显示,射流内的速度场分布远不如正常流体中均匀和规律变化,其中存在许多局部的涡旋流.沿着射流方向上速度的波动幅度越来越小,平均速度在行进了约35mm后降至2mm/s量级. 展开更多
关键词 粒子成像测速仪(PIV) 超流氦(氦II) 喷射流 涡旋流
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超流氦中的沸腾实验研究:压力测量及其可视化
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作者 张鹏 村上正秀 +1 位作者 王如竹 稻叶大纪 《工程热物理学报》 EI CAS CSCD 北大核心 2000年第6期719-723,共5页
在超流氢的沸腾实验中,随着静压液柱高度h的降低,会出现不同的沸腾状态。在噪声沸腾中,一个与平板加热器大小相当的气泡在其表面上反复地长大、缩小,并伴随着巨大的噪声和剧烈的机械振动;在无噪声沸腾中,在平板加热器表面形成一... 在超流氢的沸腾实验中,随着静压液柱高度h的降低,会出现不同的沸腾状态。在噪声沸腾中,一个与平板加热器大小相当的气泡在其表面上反复地长大、缩小,并伴随着巨大的噪声和剧烈的机械振动;在无噪声沸腾中,在平板加热器表面形成一个极稳定的气膜,并且,没有噪声和机械振动出现;而在两者之间,存在一个过渡的沸腾状态。通过沸腾过程中的压力振动测量和可视化测量,对不同沸腾状态进行了研究。 展开更多
关键词 沸腾实验 超流氦 制冷 压力测量
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Unified Theory of Force Fields (Electromagnetic and Gravitational)
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作者 Chaykin Andrey 《World Journal of Condensed Matter Physics》 2017年第1期31-35,共5页
In this paper, the superfluid substance is described by the same equations of the electromagnetic field and the gravitational field. The gravitational mass is sufficiently considered as the gravitational charge, havin... In this paper, the superfluid substance is described by the same equations of the electromagnetic field and the gravitational field. The gravitational mass is sufficiently considered as the gravitational charge, having the same dimensions as electric charge. 展开更多
关键词 GRAVITY ELECTROMAGNETIC FIELD Maxwell’s EQUATIONS HELIUM II Gravitodynamics
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