Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is im...Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is important for analyzing the thermal transport process. Due to the involvement of phasetransition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of amultifunctional instrument that integrates time domain reflectometry （TDR） sensor and thermal pulsetechnology （TPT） to measure the thermal properties of soil during phase transition. With this method,the extent of phase transition （freezing/thawing） was measured with the TDR module; and the correspondingthermal properties were measured with the TPT module. Therefore, the variation of thermalproperties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate theperformance of this measurement method. The performance of individual modules was first validatedwith designed experiments. The new sensor was then used to monitor the properties of soils duringfreezingethawing process, from which the freezing/thawing degree and thermal properties weresimultaneously measured. The results are consistent with documented trends of thermal propertiesvariations. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
In order to discover the relation between rock-soil thermal properties and strata during the process of engineering investigation,the authors studied the measuring principle of Thermal Conductivity Scanner( TCS)and me...In order to discover the relation between rock-soil thermal properties and strata during the process of engineering investigation,the authors studied the measuring principle of Thermal Conductivity Scanner( TCS)and measured the thermal properties of 45 drilling samples from Qinghai with TCS in the laboratory. The results show that the specific heat capacity( SHC) decreases while the thermal conductivity( TC) increases with the increase of the depth. With the lithological change,the specific heat capacity and thermal conductivity have the opposite trend. The depth and lithology have a greater influence on the thermal conductivity than the specific heat capacity.展开更多
A cryogenic treatment test was carried on TC4 titanium alloy,and the effects of cryogenic treatment on the thermal physical properties of TC4 titanium under the temperature range of 25~600°C were investigated thr...A cryogenic treatment test was carried on TC4 titanium alloy,and the effects of cryogenic treatment on the thermal physical properties of TC4 titanium under the temperature range of 25~600°C were investigated through comparing the variation of the thermal conductivity and thermal expansion coefficient of the alloy before and after cryogenic treatment.The results show that the thermal conductivity of the cryogenic treated alloy is first less and then greater than that of the untreated alloy,however,its thermal expansion coefficient is first greater and then less than that of the untreated alloy with the increase of temperature.When the temperature is up to 600°C,the thermal conductivity and thermal expansion coefficient of the cryogenic treated alloy are 7.24 W·m-1·K-1 and 11.71×10-6°C-1,and increased and decreased by 3.18%and 1.65%than that of the untreated alloy at the same temperature,respectively.展开更多
含氢量是影响钢材质量的主要因素,因此,准确而快速地测定含氢量对提高钢材质量具有重要意义。设计基于热导芯片TCS208F为检测核心和STC12C5A60S2单片机为控制核心的氢含量检测传感器。传感器通过内部温控电路和PID算法,实现测量气室温...含氢量是影响钢材质量的主要因素,因此,准确而快速地测定含氢量对提高钢材质量具有重要意义。设计基于热导芯片TCS208F为检测核心和STC12C5A60S2单片机为控制核心的氢含量检测传感器。传感器通过内部温控电路和PID算法,实现测量气室温度稳定,有效抑制了温漂对测量精度的影响,最大误差<1%FS。同时设计了信号调节电路和V/Ⅰ转换电路,传感器可以直接输出4〜20 m A信号,以便长距离传送信号。该传感器具有测量精度高、体积小、功耗低、响应迅速、适用范围广等优点。展开更多
文摘Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is important for analyzing the thermal transport process. Due to the involvement of phasetransition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of amultifunctional instrument that integrates time domain reflectometry （TDR） sensor and thermal pulsetechnology （TPT） to measure the thermal properties of soil during phase transition. With this method,the extent of phase transition （freezing/thawing） was measured with the TDR module; and the correspondingthermal properties were measured with the TPT module. Therefore, the variation of thermalproperties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate theperformance of this measurement method. The performance of individual modules was first validatedwith designed experiments. The new sensor was then used to monitor the properties of soils duringfreezingethawing process, from which the freezing/thawing degree and thermal properties weresimultaneously measured. The results are consistent with documented trends of thermal propertiesvariations. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
基金Supported by National High Technology Research and Development Program of China(863 Project)(No.2012AA052801)National Natural ScienceFoundation of China(No.41372239)Specialized Research Fund for the Doctoral Program of Higher Education(No.20110061110055)
文摘In order to discover the relation between rock-soil thermal properties and strata during the process of engineering investigation,the authors studied the measuring principle of Thermal Conductivity Scanner( TCS)and measured the thermal properties of 45 drilling samples from Qinghai with TCS in the laboratory. The results show that the specific heat capacity( SHC) decreases while the thermal conductivity( TC) increases with the increase of the depth. With the lithological change,the specific heat capacity and thermal conductivity have the opposite trend. The depth and lithology have a greater influence on the thermal conductivity than the specific heat capacity.
文摘A cryogenic treatment test was carried on TC4 titanium alloy,and the effects of cryogenic treatment on the thermal physical properties of TC4 titanium under the temperature range of 25~600°C were investigated through comparing the variation of the thermal conductivity and thermal expansion coefficient of the alloy before and after cryogenic treatment.The results show that the thermal conductivity of the cryogenic treated alloy is first less and then greater than that of the untreated alloy,however,its thermal expansion coefficient is first greater and then less than that of the untreated alloy with the increase of temperature.When the temperature is up to 600°C,the thermal conductivity and thermal expansion coefficient of the cryogenic treated alloy are 7.24 W·m-1·K-1 and 11.71×10-6°C-1,and increased and decreased by 3.18%and 1.65%than that of the untreated alloy at the same temperature,respectively.
文摘含氢量是影响钢材质量的主要因素,因此,准确而快速地测定含氢量对提高钢材质量具有重要意义。设计基于热导芯片TCS208F为检测核心和STC12C5A60S2单片机为控制核心的氢含量检测传感器。传感器通过内部温控电路和PID算法,实现测量气室温度稳定,有效抑制了温漂对测量精度的影响,最大误差<1%FS。同时设计了信号调节电路和V/Ⅰ转换电路,传感器可以直接输出4〜20 m A信号,以便长距离传送信号。该传感器具有测量精度高、体积小、功耗低、响应迅速、适用范围广等优点。
