With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the ...With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the two methods because mine water inrush in many old coal mines in China is limited. What is more, the cooling pipelines cannot be put in narrow pit-shaft. To settle the problem above, according to the characteristics of Zhangxiaolou Coal Mine, this paper adopts the deep mine return air as the cooling energy for deep mine cooling system. In addition, we carried out cite test to extract cold energy from return air. Through monitoring the water quantity, water temperature of cooling system and air temperature, we got the thermodynamic equilibrium parameters during the cooling energy acquisition analysis and the effect of cooling system that the temperature and humidity on working face are respectively reduced to 8-12 ℃ and 8-15% through cooling. This research offers experimental reference for deep mine cooling which lacks cooling energy.展开更多
On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy tem...On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy temperature of its progeny can be descended universally and some non-cold type acceptor wheat can turn into cold type wheat having good metabolic functions under the condition of that acceptor wheat accepts the gamete of donor wheat supplying a low temperature. Contrast between wheat cold source and general wheat having no the ability of supplying a low temperature shows that second heat source temperature and plant temperature of wheat cold source not only are lower than those of general wheat but its root vigor, rate of awn etiolation, functional duration of leaf, chlorophyll content, soluble protein content, SOD activity, net photosynthetic rate, etc, are also more excellent than those of general wheat, and these all provide certain ecological and physiological bases for the distinction and selection of wheat cold source.展开更多
This paper has developed and characterized a method to produce a velocity-tunable ^87Rb cold atomic source for atomic interferometry application. Using a high speed fluorescence imaging technology, it reports that the...This paper has developed and characterized a method to produce a velocity-tunable ^87Rb cold atomic source for atomic interferometry application. Using a high speed fluorescence imaging technology, it reports that the dynamic process of the atomic source formation is observed and the source performances including the flux and the initial velocity are characterized. A tunable atomic source with the initial velocity of 1.4-2.6 m/s and the atomic source flux of 2× 10^8 - 6 × 10^9 atoms/s has been obtained with the built experimental setup.展开更多
Dipole Research EXperiment(DREX) is a new terrella device as part of the Space Plasma Environment Research Facility(SPERF) for laboratory studies of space physics relevant to the inner magnetospheric plasmas. Adeq...Dipole Research EXperiment(DREX) is a new terrella device as part of the Space Plasma Environment Research Facility(SPERF) for laboratory studies of space physics relevant to the inner magnetospheric plasmas. Adequate plasma sources are very important for DREX to achieve its scientific goals. According to different research requirements, there are two density regimes for DREX. The low density regime will be achieved by an electron cyclotron resonance(ECR) system for the ‘whistler/chorus' wave investigation, while the high density regime will be achieved by biased cold cathode discharge for the desired ‘Alfvén' wave study. The parameters of ‘whistler/chorus' waves and ‘Alfvén' waves are determined by the scaling law between space and laboratory plasmas in the current device. In this paper, the initial design of these two plasma sources for DREX is described. Focus is placed on the chosen frequency and operation mode of the ECR system which will produce relatively low density ‘artificial radiation belt' plasmas and the seed electrons, followed by the design of biased cold cathode discharge to generate plasma with high density.展开更多
In order to ensure the safe operation of the compressors used in water chillers,in the present study some interlock protections have been added to the related design.These include a low pressure protection,a high pres...In order to ensure the safe operation of the compressors used in water chillers,in the present study some interlock protections have been added to the related design.These include a low pressure protection,a high pressure protection,an exhaust temperature protection and a differential pressure protection.Some tests have been conducted by tuning the saturation suction and exhaust temperatures of the compressor through adjustment of the cold source outlet temperature and the ambient temperature.The results show that the ambient temperature increases with decreasing device load and increasing fan speed under the same saturated suction temperature;the device refrigerating capacity steps up with augmenting load and dropping saturation exhaust temperature,while it is not greatly affected by the fan speed.Moreover,the Energy efficiency ratio(COP)decreases with the rise of the saturation exhaust temperature.This parameter is not affected much by the device load and fan speed at high saturation exhaust temperature,while it improves on increasing the device load and decreasing the fan speed at low saturation exhaust temperature.展开更多
Natural gas hydrate(NGH)holds great promise as a source of clean energy.It is critical for acquiring the largest possible in situ NGH core for NGH eigen features and resource assessment.However,the existing NGH coring...Natural gas hydrate(NGH)holds great promise as a source of clean energy.It is critical for acquiring the largest possible in situ NGH core for NGH eigen features and resource assessment.However,the existing NGH coring technology has limitations,such as temperature increments,limited coring diameters,low coring rates,and complex coring structures.Therefore,this study designs and proposes an NGH freezing coring(NGHFC)method and verifies the freezing and coring capacities of the NGHFC method in laboratories and experimental wells.Results suggest that NGHFC shows good freezing and heat-retention properties.A freezing core heat transfer model is developed.According to the actual air temperature and operating time,the optimum initial temperature of the cold source can be determined using this model.The average coring rate of NGHFC can reach 77.86%.The research results will provide a new idea of coring gas hydrates.展开更多
基金Financial supports for this project, provided by the key program supported by the National Natural Science Foundation of China(No. 51134005)the Doctoral Scientific Fund Project of the Ministry of Education of China (No. 20120023120004), are gratefully acknowledged
文摘With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the two methods because mine water inrush in many old coal mines in China is limited. What is more, the cooling pipelines cannot be put in narrow pit-shaft. To settle the problem above, according to the characteristics of Zhangxiaolou Coal Mine, this paper adopts the deep mine return air as the cooling energy for deep mine cooling system. In addition, we carried out cite test to extract cold energy from return air. Through monitoring the water quantity, water temperature of cooling system and air temperature, we got the thermodynamic equilibrium parameters during the cooling energy acquisition analysis and the effect of cooling system that the temperature and humidity on working face are respectively reduced to 8-12 ℃ and 8-15% through cooling. This research offers experimental reference for deep mine cooling which lacks cooling energy.
基金the National Nature Science Foundation of China (No. 39870477,30070150).
文摘On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy temperature of its progeny can be descended universally and some non-cold type acceptor wheat can turn into cold type wheat having good metabolic functions under the condition of that acceptor wheat accepts the gamete of donor wheat supplying a low temperature. Contrast between wheat cold source and general wheat having no the ability of supplying a low temperature shows that second heat source temperature and plant temperature of wheat cold source not only are lower than those of general wheat but its root vigor, rate of awn etiolation, functional duration of leaf, chlorophyll content, soluble protein content, SOD activity, net photosynthetic rate, etc, are also more excellent than those of general wheat, and these all provide certain ecological and physiological bases for the distinction and selection of wheat cold source.
基金supported in part by National Natural Science Foundation of China (Grant No 50775127/E0525)National Basic Research Specialized Program of China (Grant No 2007CB306504)
文摘This paper has developed and characterized a method to produce a velocity-tunable ^87Rb cold atomic source for atomic interferometry application. Using a high speed fluorescence imaging technology, it reports that the dynamic process of the atomic source formation is observed and the source performances including the flux and the initial velocity are characterized. A tunable atomic source with the initial velocity of 1.4-2.6 m/s and the atomic source flux of 2× 10^8 - 6 × 10^9 atoms/s has been obtained with the built experimental setup.
基金supported by National Natural Science Foundation of China(Nos.11505040,11261140326,11405038 and 51577043)China Postdoctoral Science Foundation(Nos.2016M591518,2015M570283)HIT.NSRIF under Grant No.2017008
文摘Dipole Research EXperiment(DREX) is a new terrella device as part of the Space Plasma Environment Research Facility(SPERF) for laboratory studies of space physics relevant to the inner magnetospheric plasmas. Adequate plasma sources are very important for DREX to achieve its scientific goals. According to different research requirements, there are two density regimes for DREX. The low density regime will be achieved by an electron cyclotron resonance(ECR) system for the ‘whistler/chorus' wave investigation, while the high density regime will be achieved by biased cold cathode discharge for the desired ‘Alfvén' wave study. The parameters of ‘whistler/chorus' waves and ‘Alfvén' waves are determined by the scaling law between space and laboratory plasmas in the current device. In this paper, the initial design of these two plasma sources for DREX is described. Focus is placed on the chosen frequency and operation mode of the ECR system which will produce relatively low density ‘artificial radiation belt' plasmas and the seed electrons, followed by the design of biased cold cathode discharge to generate plasma with high density.
基金This work was supported by the National Natural Science Foundation of China(No.41877251)Major Science and Technology Projects of Xinxiang City(No.21ZD012).
文摘In order to ensure the safe operation of the compressors used in water chillers,in the present study some interlock protections have been added to the related design.These include a low pressure protection,a high pressure protection,an exhaust temperature protection and a differential pressure protection.Some tests have been conducted by tuning the saturation suction and exhaust temperatures of the compressor through adjustment of the cold source outlet temperature and the ambient temperature.The results show that the ambient temperature increases with decreasing device load and increasing fan speed under the same saturated suction temperature;the device refrigerating capacity steps up with augmenting load and dropping saturation exhaust temperature,while it is not greatly affected by the fan speed.Moreover,the Energy efficiency ratio(COP)decreases with the rise of the saturation exhaust temperature.This parameter is not affected much by the device load and fan speed at high saturation exhaust temperature,while it improves on increasing the device load and decreasing the fan speed at low saturation exhaust temperature.
基金supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08G315)National Natural Science Foundation of China No.51827901 and U2013603Shenzhen Basic Research Project(JCYJ20190808153416970)
文摘Natural gas hydrate(NGH)holds great promise as a source of clean energy.It is critical for acquiring the largest possible in situ NGH core for NGH eigen features and resource assessment.However,the existing NGH coring technology has limitations,such as temperature increments,limited coring diameters,low coring rates,and complex coring structures.Therefore,this study designs and proposes an NGH freezing coring(NGHFC)method and verifies the freezing and coring capacities of the NGHFC method in laboratories and experimental wells.Results suggest that NGHFC shows good freezing and heat-retention properties.A freezing core heat transfer model is developed.According to the actual air temperature and operating time,the optimum initial temperature of the cold source can be determined using this model.The average coring rate of NGHFC can reach 77.86%.The research results will provide a new idea of coring gas hydrates.