冷压疼痛实验范式:一种实验室疼痛诱导技术

冷压实验(the cold-pressor task/test CPT)是实验室疼痛研究手段。实验中,被试者将手掌或前臂放入冰水中,随着时间的增长,冰水会引起强度逐渐增加的疼痛感,被试者在无法继续忍受的情况下缩回手臂,实验任务就到此结束。文章从冷压实验任务的基本概念、实验仪器设计、伦理及结果测量等方面,对冷压实验进行了介绍,并为冷压疼痛实验的实施提出了一些意见和建议。

觉知训练对参与者疼痛忍耐度的影响

背景:基于接纳和觉知的疗法被誉为心理疗法的"第三潮",该类方法可以显著改善慢性疼痛患者的机体功能和社会功能,减少疼痛对患者生活的影响。目前此类方法对实验室诱发的急性疼痛的干预虽显示出一些积极的效果,但还存在争论。目的:探索觉知训练对健康大学生对实验室诱发的急性疼痛的主观感受、忍耐度,及体验疼痛时心率变化的干预效果。方法:训练组为自愿参加实验的8名首都师范大学学生,对照组为某心理学选修班的7名大学生。对训练组进行8周的觉知训练,在训练前、后采用觉知五因素量表测量训练组和对照组的觉知度,并记录两组冷压实验中的疼痛阈限、疼痛忍耐时间、对疼痛强度的主观评价及心率变化。结果与结论:用非参检验对实验数据进行分析发现,只有训练组在经觉知训练后,觉知五因素量表得分(Z=-2.366;P<0.05)和疼痛忍耐度(Z=-2.117;P<0.05)显著提高;训练组和对照组的疼痛阈限、疼痛的主观评价和心率指标前、后测差异均无显著性意义(P>0.05)。说明觉知训练可在主观疼痛程度不变的情况下增加参与者对急性疼痛的忍耐度,但对应对疼痛时的心率无显著性影响。

Experimental Performance of TJR02 as an Alternative Refrigerant to R22 in a Small-Scale Cold Storage

A refrigerant mixture TJR02 was developed and the comparison experiment was performed on a singlestage vapor compression refrigeration system originally designed for R22.Experimental results show that TJR02 can be directly used in the system without modifying the original system or changing lubricant.By replacing R22 with TJR02,cooling rate gets faster and at least 20% of energy is saved.The actual detection in the standard test-bed verifies the experimental results and indicates that the adoption of TJR02 leads to greater efficiency and wider application.And the lower the refrigeratory temperature is,the more obvious the energy saving effects will be.

Experimental Study on Thermal Interaction of LBE and Lead Droplet with Subcooled Water

Characteristics of thermal-hydraulic interaction of LBE （45w%Pb-55w%Bi） and lead with subcooled water in pool water were investigated experimentally. Two kinds of interaction zones （deformation and fragmentation） and three kinds of interaction zones （solidification, deformation and fragmentation） were observed during LBE droplet/water interaction and lead droplet/water interaction, respectively. The fragmentation zone （FZ） could be identified exactly by two border lines： spontaneous nucleation temperature and minimum film boiling temperature. Within fragmentation zone, 10% to 35% tiny debris （diameter 〈 1 mm） of LBE and 5 to 8 kPa peak pressure generated with increasing the LBE temperature and no effect with increasing the subcooling of water. Only 2%-4% tiny debris （diameter 〈 1 mm） of lead and 2 kPa peak pressure generated regardless of lead and water temperature.

Experimental Performance of Moderate and High Temperature Heat Pump Charged with Refrigerant Mixture BY-3

Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.

Cooling of Superheated Refrigerants Flowing inside Tubes Filled with Porous Media： Study of Heat Transfer and Pressure Drop, Carbon Dioxide Case Study

In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside tubes filled with porous media. Analytical empirical correlations were formulated for the coefficient of convectional heat transfer and for the pressure drop. A comparison between experimental results and that obtained by developed correlations were carried out, and a comparison between these results and literature published ones were carried out too. The results of this research showed that for cooling process the proposed correlations were proved to be acceptably accurate for pressure drop with difference from experimental results of 2%, while for convective heat transfer the difference from experimental results reached about 3%. More than 90% agreement with literature results was obtained. This work can enhance the calculations of heat flux and pressure drop of gases flow inside porous media filled tubes, and can help in the design procedure of heat exchangers and cooling processes.

Experimental Studies on Critical Heat Flux in a Uniformly Heated Vertical Tube at Low Pressure and Flowrates

Investigations into critical beat flux at low flow and pressure conditions are of particular interest when predicting the nuclear reactor core behavior during Loss of Coolant accident （LOCA）. Therefore, critical heat flux （CHF） has been investigated in a uniformly heated vertical round tube at two low system pressures and six low water flowrates. The results have been compared with two correlations which have different approaches and CHF look-up table. Good agreements have been obtained for the three comparisons at the lower sets of mass fluxes. The Bowring correlation was found to be the best to correlate the experimental results with Root Mean Square Error RMSE of 0.54% and 0.56% for the 5 bar and 15 bar system pressure respectively. A comparisons with the Shim and Lee correlation yielded RMSE of 0.23% and 5.74% for the two system pressure respectively. When the look-up table of Groeneveld et al. was used, RMES of 0.55% and 25.2% was obtained for the two system pressure respectively.

Experimental Investigation on Film Cooling Performance of Pressure Side in Annular Cascades

Experimental investigations were conducted to study the film cooling performance in a low speed annular cascades using Thermochromic Liquid Crystal (TLC) technique. The test blade was placed in the second stage, where 18 blades were installed with chord length of 124.3 mm and height of 99 mm. A film hole with diameter of 4 mm, angled 28° to the tangential of the pressure surface in streamwise, was set in the middle span of the blade. The Reynolds number based on the outlet mainstream velocity and the blade chord length of the second stage varied from 1.52×105 to 2.00×105. All measurements were made with the blowing ratio varying from 0.3 to 3.0. Air and CO2 worked as coolant to achieve the coolant-to-mainstream density ratio of 1.03 and 1.57. The results show that the film coverage and cooling effectiveness scale up with the blowing ratio. Higher density ratio can generate larger film cooling coverage and effectiveness. The higher the Reynolds number, the larger the film coverage and cooling effectiveness.