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
The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important f...The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important factors affecting the disposal phase. Economic and environmental requirements must be followed in order to achieve the best reclamation results, keeping into account site constraints such as slope stability, hauling and dumping issues, and interactions with groundwater. This paper deals with the above mentioned issues, illustrating a rational approach applied on the case of a large limestone quarry where the thickness of the overburden is relevant and the spoil material has to be dumped in a flooded pit. The proposed multidisciplinary approach led to the selection of most suitable methods for excavation, transportation and disposal. The selection was based on a detailed laboratory and site characterisation that defined favorable and adverse factors to be considered during the preliminary study of a large quarrying project.展开更多
Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still lim...Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still limited. In the present paper, the effect of coarse aggregate size （single grade of 5～10, 10～16, 16～20 and 20～25 mm） on stress-crack opening （σ-w） relation in normal and high strength concretes （compressive strength of 40 and 80 MPa, respectively） was studied. The investigation was based on three-point bending tests implemented by fictitious crack analysis. The result shows that coarse aggregate size and cement matrix strength significantly influence the shape of σ-w curve. For a given total aggregate content, in normal strength concrete, smaller size of aggregate leads to a high tensile strength and a sharp stress drop after the peak stress. The smaller the coarse aggregate, the steeper the σ-w curve. By contrast, in high strength concrete, the effect of aggregate size on σ-w relation almost vanishes. A similar σ-w relation is obtained for the concrete except for the case of 20～25 mm coarse aggregate size. The stress drop after the peak stress is more significant for high strength concrete than that for normal strength concrete. Meanwhile, the smaller the coarse aggregate size, the higher the flexural strength. Fracture energy and characteristic length increase with increasing coarse aggregate size in both normal and high strength concretes.展开更多
随着软件定义网络(Software Defined Network,SDN)成为网络世界的新的范式转移,作为SDN网络的核心组件,控制器的性能得到了越来越多的关注。文章介绍了基于Open Flow 1.3这一南向协议的SDN控制器性能测试方法,并以某开源控制器为例,介...随着软件定义网络(Software Defined Network,SDN)成为网络世界的新的范式转移,作为SDN网络的核心组件,控制器的性能得到了越来越多的关注。文章介绍了基于Open Flow 1.3这一南向协议的SDN控制器性能测试方法,并以某开源控制器为例,介绍测试结果的定量呈现方式和分析方法,为需要评估控制器性能的用户提供参考。展开更多
Rockburst,earthquake and blasting cause some dynamic loads on rock support and rock reinforcement system.Elements of rock support and rock reinforcement are generally made of steel bar or cables,which are resistant ag...Rockburst,earthquake and blasting cause some dynamic loads on rock support and rock reinforcement system.Elements of rock support and rock reinforcement are generally made of steel bar or cables,which are resistant against corrosion.These support elements may be subjected to vibrations induced by turbines,vehicle traffic and long-term corrosion in addition to dynamic loading caused by earthquake,rockburst and blasting.In this study,some theoretical,numerical and experimental studies are conducted on rockbolts and rock anchors under shaking and impulsive loading.Then the outcomes of these studies are presented and their practical implications are discussed accordingly.展开更多
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.
文摘The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important factors affecting the disposal phase. Economic and environmental requirements must be followed in order to achieve the best reclamation results, keeping into account site constraints such as slope stability, hauling and dumping issues, and interactions with groundwater. This paper deals with the above mentioned issues, illustrating a rational approach applied on the case of a large limestone quarry where the thickness of the overburden is relevant and the spoil material has to be dumped in a flooded pit. The proposed multidisciplinary approach led to the selection of most suitable methods for excavation, transportation and disposal. The selection was based on a detailed laboratory and site characterisation that defined favorable and adverse factors to be considered during the preliminary study of a large quarrying project.
文摘Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still limited. In the present paper, the effect of coarse aggregate size （single grade of 5～10, 10～16, 16～20 and 20～25 mm） on stress-crack opening （σ-w） relation in normal and high strength concretes （compressive strength of 40 and 80 MPa, respectively） was studied. The investigation was based on three-point bending tests implemented by fictitious crack analysis. The result shows that coarse aggregate size and cement matrix strength significantly influence the shape of σ-w curve. For a given total aggregate content, in normal strength concrete, smaller size of aggregate leads to a high tensile strength and a sharp stress drop after the peak stress. The smaller the coarse aggregate, the steeper the σ-w curve. By contrast, in high strength concrete, the effect of aggregate size on σ-w relation almost vanishes. A similar σ-w relation is obtained for the concrete except for the case of 20～25 mm coarse aggregate size. The stress drop after the peak stress is more significant for high strength concrete than that for normal strength concrete. Meanwhile, the smaller the coarse aggregate size, the higher the flexural strength. Fracture energy and characteristic length increase with increasing coarse aggregate size in both normal and high strength concretes.
文摘随着软件定义网络(Software Defined Network,SDN)成为网络世界的新的范式转移,作为SDN网络的核心组件,控制器的性能得到了越来越多的关注。文章介绍了基于Open Flow 1.3这一南向协议的SDN控制器性能测试方法,并以某开源控制器为例,介绍测试结果的定量呈现方式和分析方法,为需要评估控制器性能的用户提供参考。
文摘Rockburst,earthquake and blasting cause some dynamic loads on rock support and rock reinforcement system.Elements of rock support and rock reinforcement are generally made of steel bar or cables,which are resistant against corrosion.These support elements may be subjected to vibrations induced by turbines,vehicle traffic and long-term corrosion in addition to dynamic loading caused by earthquake,rockburst and blasting.In this study,some theoretical,numerical and experimental studies are conducted on rockbolts and rock anchors under shaking and impulsive loading.Then the outcomes of these studies are presented and their practical implications are discussed accordingly.
