变温实验中冷和热刺激反应强度的差异

目的 了解变温实验检查中冷和热刺激对患者反应强度变化有无影响。方法 应用眼震电图仪和冷热刺激仪对 12 0例有眩晕症状的患者进行冷热实验检查 ,观察他们在不同温度刺激下眼震的最大慢相角速度。结果 单热刺激以及先冷后热刺激中的热刺激引起的患者眼震的最大慢相角速度较冷刺激组明显大 (P <0 .0 1)。

棱镜式激光陀螺变温实验中多横模干涉研究

利用环形激光器模式理论,分析了多横模起振对激光陀螺干涉光斑的影响。结合高、低温下,棱镜式环形谐振腔光路微位移等特点,研究了光阑限模结构对陀螺限模质量稳定性的影响。利用猫眼激光器获得高阶横模单独振荡,研究了不同阶次横模干涉光斑的形貌特征,结合实验中记录到的变温条件下激光陀螺合光光斑,分析棱镜式激光陀螺合光光斑畸化对陀螺正常工作的影响。

变温蠕变实验的COP微流控芯片热压制备

采用热压方法制备了COP微流控芯片。由于温度对微结构热压成形的质量影响最大,基于材料的粘弹性特性,通过变温准蠕变实验获得热压参考温度Tr,即从材料玻璃点温度以下开始,以1.5℃/min的温升速率,在热压工作压力下热压聚合物基片,通过温度-位移实时采集系统获得材料的温度-形变曲线,曲线的拐点对应的温度即是热压参考温度。实验证明了在该温度下热压成形具有高复制精度和低整体变形,微结构宽度和深度方向的复制精度分别达到97.6%和94.3%。电泳实验和DNA分析实验得出COP芯片具有良好的生物兼容性,适用于生化分析。

利用真空变温薄膜电阻实验仪测量热电材料特性参数

利用北京交通大学理学院自主开发的VTR10型真空变温薄膜电阻实验仪对热电材料的热电阻率进行了多次测量,并用该装置精确测定了热电材料的塞贝克系数,得到了热电材料的电阻率随温度变化的曲线和塞贝克系数随温度变化的曲线.

无烟煤变温变压吸附实验数据的数学分析

煤炭科学研究总院西安研究院报道的无烟煤变温变压吸附实验有测试点少(12点)、涉及温度(18~72℃)及压力(1~19MPa)范围宽、更符合煤层气排采的实际情况的优点可以在煤层气或页岩气吸附-解吸研究中应用。LI吸附-流动方程既可以处理变温变压吸附实验数据,也可以处理系列等温吸附实验数据,并可以将处理结果可视化。LI吸附-流动方程的偏导数、偏微分和全微分可以解释并计算变温变压吸附实验现象和吸附量极大值。

相变温控实验及在航天器上应用

一、前言将相变材料的潜热用于温控,是现代出现的新技术。这种技术首先应用于航天器的温控,引起了广泛的兴趣和高度重视,因此又叫“航天温控”。在地面可以对大量高功率密度的电子元器件进行温控;对半导体致冷器热端进行温控;对飞机上的元器件及高精度仪器进行严格温控;在太阳能储存方面也有着广阔的应用前景。通常情况下,我们采用的型材散热器、平板散热器、叉指散热器。

2-氟-8-溴-5,11-二甲基二苯并[1,5][b,f ] 二氮杂辛变温核磁共振的研究

本工作通过变温实验获取化合物(分子式为C_(16)H_(16)N_(2) FBr)理想的1D,2D核磁共振谱图,在此基础上顺利地完成该化合物的结构确定。随后,又利用HMR的实验结果求算出该化合物的转环速率及其能垒,为该化合物合成线路的设计合理性和进一步研究提供依据。

变温变压下煤层气吸附量的预测

等温吸附虽然被大量学者进行研究并用于煤层气储量的预测,由于其实验条件不符合实际开采过程中的地温与地压,故很多专家提出用变温变压的实验条件来预测煤层气的吸附量,但是到目前为止鲜有很好的方程来处理变温变压实验数据。本文基于煤炭科学研究总院西安研究院张庆玲对4种不同煤级煤样在变温变压吸附实验的研究,提出了温度-压力-吸附量方程(TPAE方程)用于煤层气在温度和压力共同影响下吸附量的预测。通过TPAE方程,对4种不同煤级在变温变压下吸附量进行回归预测。结果表明:TPAE方程可以非常好地处理变温变压吸附实验数据,4种煤样的回归计算值与实测值最大平均相对误差为2.64%,最小为1.63%,同时实现温度和压力及吸附量三维视图的可视化,从图中可知任意温度和压力下煤层气的吸附量。

程序变湿法研究双氯西林钠的稳定性

报道了一种研究固体药物对湿度稳定性的新的实验方法——程序变湿法,通过一次程序变湿和一次程序变温加速试验,得到与湿度和温度有关的药物降解的全部动力学参数;设计了用电子计算机控制程序变湿和程序变温的装置,其湿度波动小于±0.5%,温度波动小于±0.1℃;以双氯西林钠为体系,采用线性程序变湿和倒数程序变温实验研究了其稳定性.结果表明程序变湿和变温加速实验与恒温恒湿对照实验得到的降解动力学参数基本一致.

N-甲酰基化合物的NMR谱的研究

测定了一系列Ｎ甲酰基化合物的ＮＭＲ 波谱，对其一般特征进行了对比、讨论，尤其注意到由于ＣＮ 键的双键性而产生的异构体的性质以及氢键对于异构体的稳定作用．

水合物低场核磁共振弛豫响应

水合物核磁共振表征对于海上水合物储层勘探以及地层描述具有重大意义。设计实验探究了溴化四丁基铵(TBAB)水溶液在分级降温与升温过程中的低场核磁共振弛豫响应特征。实验数据结果表明,变温过程中横向弛豫时间(T2)分布存在3个区间,即小峰区间(小于4 ms)、中峰区间(4~100 ms)和大峰区间(100~3000 ms),核磁共振弛豫信号分别来源于水合物、TBAB分子和水中的氢原子核。测试样品的温度以及T2分布演化规律能够识别样品中所包含物质,即固态水合物、TBAB水溶液、水、冰。小峰信号由水合物提供,依此建立了水合物核磁共振信号(幅值和T2)与温度的关系,可以作为量化分析水合物含量的温度校准依据。

环烯烃聚合物（COP）微流控芯片的制备及其与聚甲基丙烯酸甲酯（PMMA）微流控芯片的性能对比

采用热压方法制备了环烯烃聚合物（COP）微流控芯片。考虑到温度对微结构热压成形的质量影响最大,基于材料的粘弹性特性,通过变温准蠕变实验获得了热压参考温度Tr。实验证明,在该温度下热压成形,宽度和深度方向的复制精度分别达到了97.6%和94.3%。为了研究制备的COP微流控芯片的性能,将其和同一模具制备的PMMA微流控芯片进行了性能对比实验。通过背景荧光实验、电泳实验和DNA分析实验三方面的研究表明,与PMMA芯片相比,COP芯片背景荧光低,电泳效率高,检测重现性相对标准偏差小于2.5%,适用于生化分析。

Deformation mechanism and forming properties of 6061Al alloys during compression in semi-solid state

The 6061 semi-solid aluminium alloy feedstocks prepared by near-liquidus casting were compressed in semi-solid state by means of Gleeble-3500 thermal-mechanical simulator.The relationship between the true stress and the true strain at different temperatures and strain rates was studied with the deformation degree of 70%.The microstructures during the deformation process were characterized.The deformation mechanism and thixo-forming properties of the semi-solid alloys were analyzed.The results show that the homogeneous and non-dendrite microstructures of semi-solid 6061Al alloy manufactured by near-liquidus casting technology could be transformed into semi-solid state with the microstructure suitable for thixo-forming which are composed of near-spherical grains and liquid phase with eutectic composition through reheating process.The deformation temperature and strain rate affect the peak stress significantly rather than steady flow stress.The resistance to deformation in semi-solid state decreases with the increase of the deformation temperature and decrease of the strain rate.At steady thixotropic deformation stage, the thixotropic property is uniform, and the main deformation mechanism is the rotating or sliding between the solid particles and the plastic deformation of the solid particles.

Experimental and theoretical study on thermal and moisture characteristics of new-type bamboo structure wall

Thermal and moisture characteristics of the bamboo structure wall were tested in natural climate and three representative variation processes of heat and moisture： heating from solar radiation in summer at normal temperature and humidity, heating from solar radiation in summer at normal temperature and high humidity after rain, humidifying from brash in summer at high temperature and normal humidity. The results show that, in summer, the largest temperature difference between external and internal surface of the 28 mm-thick bamboo plywood wall is 11.73℃ （at 15：40） and the largest strain difference is 136 μm/m （at 18：50）, both in ambient and indoor conditioned environment. In heating process, lengthways of the wall surface are in contracting strain while transverse ways are in expanding strain at initial stage and in contracting strain during later period. When the high temperature wall is humidified by rain, the surface temperature drops, moisture content increases and the expanding strain is presented on the surface during the whole process. Temperature and moisture content are two important factors which affect thermal and moisture stress （TMS） of the bamboo structure wall. The TMS is not only related to temperature and moisture content, but also greatly affected by temperature gradient, moisture content gradient and rates of changing.

An experiment discovery about gravitational force changes in materials due to temperature variation

The authors discovered in first time that the weight of materials or its gravitational force by earth related to its temperature and its ferromagnetism. An experiment was designed to elevate the temperatures of six different materials （Au, Ag, Cu, Fe, Al, Ni） up to 600 ℃and precisely measured their weights. It is found all the materials weigh about 0.33 ‰ - 0. 82 ‰ less. For example the weight of silver sample weighted by a precision electronic scale in a manner of special design decreases about 0.8 ‰, when its temperature is elevated to 600 ℃. Thus different metals＇ gravitational forces or weights are adjusted with temperature variation.

Experimental study on the variation law of coal temperature during excavation in coal mines

By testing the temperature of the coal and the stress of the working surface, we got the variation law of coal temperature and coal stress during the excavation. The result shows that the activities of mining affect the coal temperature, the fluctuation of coal temperature and the coal stress is synchronous. During the smooth change of crustal stress, the coal temperature basically keeps unchanged, when the dynamic phenomenon appears, the coal temperature changes, as well the coal stress. Therefore, we can use the online coal temperature monitoring system to test the coal temperature of the working surface continuously, and it can provide basic information for forecasting coal mine power disaster before it happens.

Rheological characterization of A201 aluminum alloy

The thermodynamic characterization as well as the rheological characterization of the A201 alloy were conducted.Thermodynamic simulations (CALPHAD method) and calorimetric experiments were performed to determine the solidus and liquidus temperatures, the melting range and the sensitivity of the solid fraction at the thixoforming temperatures.The rheology of aluminium alloy A201 was examined using a high temperature Searle rheometer.The flow behaviour was analyzed with concentric cylinders of graphite to avoid chemical interactions with the liquid or semi-solid aluminium.The rotational body was grooved to prevent a phenomenon called wall slippage.Continuous cooling experiment was used to observe the shear rate effects on the flow behaviour.It can be seen that the viscosity level decreases at higher shear rates.Shear rate jump experiment was carried out to evaluate the steady state flow curve within the analyzed shear rate range from 60 s-1 to 260 s-1.It is found that the power law indexes are-1.35 and-1.49 for 35% and 45% solid fraction, respectively.Finally, some mechanical property data of as-cast and as-thixoformed A201 alloy are included indicating the potential for high strength applications.

Visco-elastoplastic damage constitutive model for compressed asphalt mastic

In order to describe the three-stage creep behavior of compressed asphalt mastic, a visco-elastoplastic damage constitutive model is proposed in this work. The model parameters are treated as quadratic polynomial functions with respect to stress and temperature. A series of uniaxial compressive creep experiments are performed at various stress and temperature conditions in order to determine these parameter functions, and then the proposed model is validated by comparison between the predictions and experiments at the other loading conditions. It is shown that very small permanent deformation at low stress and temperature increases rapidly with elevated stress or temperature and the damage may initiate in the stationary stage but mainly develops in the accelerated stage. Compared with the visco-elastoplastic models without damage, the predictions from the proposed model is in better agreement with the experiments, and can better capture the rate-dependency in creep responses of asphalt mastic especially below its softening point of 47 ℃

Responses of Planetary Waves to Global Warming: Implications from CMIP3 4×CO_2 Experiments

The planetary wave response to global warm ing with single forcing of greenhouse gases （GHGs） is investigated in this study by using a total of 11 model results that anticipated CMIP3 4XCO2 experiments. It is shown that the amplitudes of the planetary wave fluxes over Siberia, the Eastern North Pacific, and the North Atlantic decrease by approximately -10% to -30% in the warming context. In particular, the vertical wave flux over the Eastern North Pacific significantly decreases by -28.6%. The weakening of the planetary waves is partly associated with the decreased land-sea thermal contrast, which may be caused by the radiation effect of CO2 and the different surface heat capacities of land and sea. The present work provides a clear understanding of the re sponses of planetary waves to GHGs forcing.