In the Da Hinggan Mountains,the safe and smooth operation of shallowly buried oil pipelines is threatened greatly by the frozeneheave damage derived from frozen soil.At present,a closed frozeneheave simulation test is...In the Da Hinggan Mountains,the safe and smooth operation of shallowly buried oil pipelines is threatened greatly by the frozeneheave damage derived from frozen soil.At present,a closed frozeneheave simulation test is often carried out in China,with water content and dry density of samples being assumed to be constant.However,an open frozeneheave test,all the factors of which change as the test goes on,can reflect the real frozeneheave damage more accurately.In this paper,the open frozeneheave test was carried out on five types frozen soil along the ChinaeRussia Crude Oil Pipeline to measure the frozeneheave factor and water content of each soil sample and accordingly analyze their relationship.Besides,its test results were compared with that of the closed frozeneheave test.Then,the normal frozeneheave force was measured by using the displacement limiting method,and this measurement was compared with the result of the static equilibrium test.Finally,a difference significance test was conducted.It is shown that the frozeneheave factor of the open test is higher than that of the closed test;the frozeneheave factor of fine grained soil has a significant effect on the frozeneheave factor of soils,and the frozeneheave factor increases as the capillary effect or the swabbing action of soil increases;the frozeneheave factor of coarse grained soil is mainly dependent on the mud content,and it is lower than that of fine grained soil;the value of frozeneheave force is in close relation with the test methods and the sample height;it is indicated that the open frozeneheave test is more applicable to the investigation on the frozeneheave of the foundation soils of pipelines in the Da Hinggan Mountains.It is concluded that the soils for the cushion and digging/packing layers of the pipelines in the permafrost regions shall be acted by the gravel or detritus with lower mud content,and waterproof and draining pipeline jetty shall be made from the clay soils with a higher plasticity.展开更多
In 1979, the Changchun Jingyuetan Remote Sensing Study and Test Site (RSSTS)began its work, and it was formally established in 1985. The RSSTS is subordinated the Changchun Branch of Chinese Academy of Sciences and is...In 1979, the Changchun Jingyuetan Remote Sensing Study and Test Site (RSSTS)began its work, and it was formally established in 1985. The RSSTS is subordinated the Changchun Branch of Chinese Academy of Sciences and is supported by the Changchun Institute of Geography and Changchun Institute of Optics and Fine Machnics, Chinese Academy of Sciences. It is under the management of the Resource & Environment Bureau of Chinese Academy of Sciences and it is the study base of remote sensing basis and application tests in China. The RSSTS is situated in the Jingyuetan scenic spot of the suburbs of Changchun City, Jilin Province. It is located at 43°40′—43°50′N and 125°18′-125°18′E.展开更多
This study tested a novel method designed to provide useful information for medical diagnosis and treatment. We measured electroencephalography (EEG) during a test of eye opening and closing, a common test in routine ...This study tested a novel method designed to provide useful information for medical diagnosis and treatment. We measured electroencephalography (EEG) during a test of eye opening and closing, a common test in routine EEG examination. This test is mainly used for measuring the degree of alpha blocking and sensitivity during eyes opening and closing. However, because these factors depend on the subject’s awareness, drowsiness can interfere with accurate diagnosis. We sought to determine the optimal EEG frequency band and optimal brain region for distinguishing healthy individuals from patients suffering from several neurophysiological diseases (including dementia, cerebrovascular disorder, schizophrenia, alcoholism, and epilepsy) while fully awake, and while in an early drowsy state. We tested four groups of subjects (awake healthy subjects, drowsy healthy subjects, awake patients and drowsy patients). The complexity of EEG band frequencies over five lobes in the human brain was analyzed using wavelet-based approximate entropy (ApEn). Two-way analysis of variance tested the effects of the two factors of interest (subjects’ health state, and subjects’ wakefulness state) on five different lobes of the brain during eyes opening and closing. The complexity of the theta and delta bands over frontal and central regions, respectively, was significantly greater in the healthy state during eyes opening. In contrast, patients exhibited increased complexity of gamma band activity over the temporal region only, during eyes-close. The early drowsy state and wakefulness state increased the complexity of theta band activity over the temporal region only during eyes-close and eyes-open states respectively, and this change was significantly greater in control subjects compared with patients. We propose that this method may be useful in routine EEG examination, to aid medical doctors and clinicians in distinguishing healthy individuals from patients, regardless of whether the subject is fully awake or in the early stages of drowsiness.展开更多
This paper presents a numerical analysis of a material test program investigating the crack opening properties of fibre reinforced concrete （FRC） round determinate panels （RDP）. The objective of this research is t...This paper presents a numerical analysis of a material test program investigating the crack opening properties of fibre reinforced concrete （FRC） round determinate panels （RDP）. The objective of this research is to set up a modified RDP test method to improve the current ASTM C1550 test method for FRC and fibre reinforced shotcrete （FRS） composite. By this test method, light small-diameter panels are applied and more crack information can be obtained by a new rotation angle measuring technique. It is shown that this modified test method can be used to effectively evaluate the crack opening resistance of FRC. The finite element analysis was then performed to clarify the crack propaga- tions and failure mode of FRC RDP panels. It helps establish a reasonable theoretical method to predict the structural response of RDP. combining with this modified testing technioue.展开更多
基金Project supported by the National Natural Science Foundation Project“Research on the Frozeneheave Mechanism of Marsh Turfy Soil in Seasonally Frozen Area”(No.41502272)Seed Fund Project of Changchun Institute of Technology,“Research on the FrozeneThaw Cycle Effect of Shallowly Buried Pipelines in the Permafrost Zone of Da Hinggan Mountains”(No.320160017).
文摘In the Da Hinggan Mountains,the safe and smooth operation of shallowly buried oil pipelines is threatened greatly by the frozeneheave damage derived from frozen soil.At present,a closed frozeneheave simulation test is often carried out in China,with water content and dry density of samples being assumed to be constant.However,an open frozeneheave test,all the factors of which change as the test goes on,can reflect the real frozeneheave damage more accurately.In this paper,the open frozeneheave test was carried out on five types frozen soil along the ChinaeRussia Crude Oil Pipeline to measure the frozeneheave factor and water content of each soil sample and accordingly analyze their relationship.Besides,its test results were compared with that of the closed frozeneheave test.Then,the normal frozeneheave force was measured by using the displacement limiting method,and this measurement was compared with the result of the static equilibrium test.Finally,a difference significance test was conducted.It is shown that the frozeneheave factor of the open test is higher than that of the closed test;the frozeneheave factor of fine grained soil has a significant effect on the frozeneheave factor of soils,and the frozeneheave factor increases as the capillary effect or the swabbing action of soil increases;the frozeneheave factor of coarse grained soil is mainly dependent on the mud content,and it is lower than that of fine grained soil;the value of frozeneheave force is in close relation with the test methods and the sample height;it is indicated that the open frozeneheave test is more applicable to the investigation on the frozeneheave of the foundation soils of pipelines in the Da Hinggan Mountains.It is concluded that the soils for the cushion and digging/packing layers of the pipelines in the permafrost regions shall be acted by the gravel or detritus with lower mud content,and waterproof and draining pipeline jetty shall be made from the clay soils with a higher plasticity.
文摘In 1979, the Changchun Jingyuetan Remote Sensing Study and Test Site (RSSTS)began its work, and it was formally established in 1985. The RSSTS is subordinated the Changchun Branch of Chinese Academy of Sciences and is supported by the Changchun Institute of Geography and Changchun Institute of Optics and Fine Machnics, Chinese Academy of Sciences. It is under the management of the Resource & Environment Bureau of Chinese Academy of Sciences and it is the study base of remote sensing basis and application tests in China. The RSSTS is situated in the Jingyuetan scenic spot of the suburbs of Changchun City, Jilin Province. It is located at 43°40′—43°50′N and 125°18′-125°18′E.
文摘This study tested a novel method designed to provide useful information for medical diagnosis and treatment. We measured electroencephalography (EEG) during a test of eye opening and closing, a common test in routine EEG examination. This test is mainly used for measuring the degree of alpha blocking and sensitivity during eyes opening and closing. However, because these factors depend on the subject’s awareness, drowsiness can interfere with accurate diagnosis. We sought to determine the optimal EEG frequency band and optimal brain region for distinguishing healthy individuals from patients suffering from several neurophysiological diseases (including dementia, cerebrovascular disorder, schizophrenia, alcoholism, and epilepsy) while fully awake, and while in an early drowsy state. We tested four groups of subjects (awake healthy subjects, drowsy healthy subjects, awake patients and drowsy patients). The complexity of EEG band frequencies over five lobes in the human brain was analyzed using wavelet-based approximate entropy (ApEn). Two-way analysis of variance tested the effects of the two factors of interest (subjects’ health state, and subjects’ wakefulness state) on five different lobes of the brain during eyes opening and closing. The complexity of the theta and delta bands over frontal and central regions, respectively, was significantly greater in the healthy state during eyes opening. In contrast, patients exhibited increased complexity of gamma band activity over the temporal region only, during eyes-close. The early drowsy state and wakefulness state increased the complexity of theta band activity over the temporal region only during eyes-close and eyes-open states respectively, and this change was significantly greater in control subjects compared with patients. We propose that this method may be useful in routine EEG examination, to aid medical doctors and clinicians in distinguishing healthy individuals from patients, regardless of whether the subject is fully awake or in the early stages of drowsiness.
基金Supported by the National Natural Science Foundation of China (50708084)Wuhan Chenguang Science and Technology Project for Young Experts (20035002016-30)
文摘This paper presents a numerical analysis of a material test program investigating the crack opening properties of fibre reinforced concrete （FRC） round determinate panels （RDP）. The objective of this research is to set up a modified RDP test method to improve the current ASTM C1550 test method for FRC and fibre reinforced shotcrete （FRS） composite. By this test method, light small-diameter panels are applied and more crack information can be obtained by a new rotation angle measuring technique. It is shown that this modified test method can be used to effectively evaluate the crack opening resistance of FRC. The finite element analysis was then performed to clarify the crack propaga- tions and failure mode of FRC RDP panels. It helps establish a reasonable theoretical method to predict the structural response of RDP. combining with this modified testing technioue.
