In Verlinde＇s entropic force scenario of gravity, Newton＇s laws and Einstein equations can be obtained from the first principles and general assumptions. However, the equipartition law of energy is invalid at very l...In Verlinde＇s entropic force scenario of gravity, Newton＇s laws and Einstein equations can be obtained from the first principles and general assumptions. However, the equipartition law of energy is invalid at very low temperatures. We show clearly that the threshold of the equipartition law of energy is related with horizon of the universe. Thus, a one-dimensional Debye （ODD） model in the direction of radius of the modified entropic force （MEF） may be suitable in description of the accelerated expanding universe. We present a Friedmann cosmic dynamical model in the ODD-MEF framework. We examine carefully constraints on the ODD-MEF model from the Union2 compilation of the Supernova Cosmology Project （SCP） collaboration, the data from the observation of the large-scale structure （LSS） and the cosmic microwave background （CMB）, i.e. SNe Ia＋LSS＋CMB. The combined numerical analysis gives the best-fit value of the model parameters （ -10^-9 and Ωm0= 0.224, with 2 = Xmin= 591.156. The corresponding age of the universe agrees with the result of D. Spergel et al. [J.M. Bardeen, B. Carter, and S.W. Hawking, Commun. Math. Phys. 31 （1973） 161] at 95% confidence level. The numerical result also yields an accelerated expanding universe without invoking any kind of dark energy. Taking ζ（= 2πωD/ H0 ） as a running parameter associated with the structure scale r, we obtain a possible unified scenario of the asymptotic flatness of the radial velocity dispersion of spiral galaxies, the accelerated expanding universe and the Pioneer 10/11 anomaly in the entropic force framework of Verlinde.展开更多
This article seeks to develop a fuller understanding of the social and attraction motives of domestic tourists who visit the Changbai Mountain Biosphere Reserve(CMBR) in Northeastern China. To do so, ecotourists are c...This article seeks to develop a fuller understanding of the social and attraction motives of domestic tourists who visit the Changbai Mountain Biosphere Reserve(CMBR) in Northeastern China. To do so, ecotourists are compared to general travelers visiting this area. A questionnaire was employed to collect data on visitor characteristics and motivations, responses to which were then analyzed via descriptive statistics, T-tests and principal component factor analysis. Results showed that 16% of the visitors to this area were classified as ecotourists, while the remainder general travelers. Five motivations displayed significant differences(P<0.05) between these two types of tourists. Three social motives – boosting self-confidence, feeling at home away from home and being together with family – and two attraction motives – indoor sports and viewing unique landscapes of the CMBR(crater lake, waterfall, gorge and hot spring) – were significantly more important for general travelers(P<0.05); while two social motives of experiencing the tranquility of the natural setting and the natural beauty of the landscape were relatively more important for ecotourists(P<0.1). Results suggest that ecotourists have distinct and complicated attraction and social motives compared to general travelers visiting the CMBR. Results have useful implications for researchers interested in tourist motivations and behavior, as well as for managers who wish to focus their marketing strategies more effectively. National Park of South Africa. Uysal et al.(1994) assessed the travel motives of Australian tourists to U.S. national parks and nature areas and formed five groupings including ‘relaxation/hobbies', ‘novelty', ‘enhancement of kinship relationship', ‘escape', and ‘prestige'. Tao et al.(2004) analyzed motivations of Asian tourists travelling to Taiwan's Taroko National Park using a self-defined approach and found that the most significant benefits sought by self-defined ecotourists are ‘learning about nature' and ‘participating in recreation activities'. Beh and Bruyere(2007) analyzed visitor motivations in three Kenyan national reserves, identifying the three most prominent kinds of tourists as escapers, learners and spiritualists. Pan and Ryan(2007) used factor analysis to reveal five motivational dimensions –‘relaxation', ‘social needs', ‘a sense of belonging', ‘mastery skills', and ‘intellectual needs' – of visitors to the Pirongia Forest Park in New Zealand. Kruger and Saayman(2010) did a comparative study on travel motivations of tourists to Kruger and Tsitsikamma National Parks in South Africa and found that common motives of tourists were ‘escape and relaxation' as well as ‘knowledge seeking', ‘nostalgia' and ‘park attributes'. Despite these efforts, on an overall basis past literature on why visitors travel to national parks and nature areas is still rather limited. In China, a number of empirical studies on tourist motivations have been conducted since the early 1990s(Chen and Miao 2006; Dong 2011; Huang et al. 2011; Jeffrey and Xie 1994; Lu 1997; Ma et al. 2013; Zhang 2012). Some studies have focused on motivations of visitors to nature reserves(Li 2007), geological parks(Chen and Qiao 2010), world heritage sites(Su et al. 2005), and seismic memorial sites(Tang 2014). However, most previous research findings on tourist motivations are not comparable, reflecting the fact that visitors to different parks have quite different motives due to the attributes of particular destinations, the geographic locations of these parks, types of available activities, marketing strategies, and the complexity of travel motives(Chen and Qiao 2010; Pan and Ryan 2007). While it is true that certain motivations were shared in varying degrees by most tourists to these places – i.e., ‘appreciating natural landscapes', ‘family and education', ‘social needs', and ‘perceived prestige of visit' – most previous research has not focused on natural settings as destinations. Thus travel motivations of tourists to these areas must be further explored and clarified in relation to impacts on particular natural areas and patterns of market segmentation. As one of the earliest and largest natural reserves established in China, the Changbai Mountain Biosphere Reserve(CMBR) has long been a draw not only for domestic tourists but also for international visitors, and tourism to the area has been growing steadily since 1980. With the number of visitors to the reserve having climbed to 2.44 million in 2010(Statistical Communiqué of the Changbai Mountain Protection and Development Zone of Jilin Province 2011), it has become imperative for local government officials and reserve wardens to understand tourists' desires and interests when identifying tourism development opportunities. However, the existing literature still suffers from a lack of empirical studies that investigate why people travel to the CMBR and whether tourist motives differ between groups such as ecotourists and general travelers. The target population for this study consists of domestic visitors to the CMBR. The goals of this research include:(1) to identify the social and attraction motives of domestic tourists that influence decisions to visit the CMBR;(2) to explore whether there are any differences between the motivations of these two types of tourists; and(3) to provide some useful management implications for local government and tourism marketers.展开更多
The performance of the Ordered-Statistic Smallest Of (OSSO) Constant False Alarm Rate (CFAR) with binary integration in Weibull background with known shape parameter is analyzed, in the cases that the processor operat...The performance of the Ordered-Statistic Smallest Of (OSSO) Constant False Alarm Rate (CFAR) with binary integration in Weibull background with known shape parameter is analyzed, in the cases that the processor operates in homogeneous background and non-homogeneous situation caused by multiple targets and clutter edge. The analytical models of this scheme for the performance evaluation are given. It is shown that the OSSO-CFAR with binary integration can greatly improve the detection performance with respect to the single pulse processing case. As the clutter background becomes spiky, a high threshold S of binary integration (S/M) is required in order to obtain a good detection performance in homogeneous background. Moreover, the false alarm performance of the OSSO-CFAR with binary integration is more sensitive to the changes of shape parameter or power level of the clutter background.展开更多
Lightning is a typical example of an instantaneous random point source target. It has close connection with severe convective phenomena such as a thunderstorm, whose distribution, variation, position and forecasting c...Lightning is a typical example of an instantaneous random point source target. It has close connection with severe convective phenomena such as a thunderstorm, whose distribution, variation, position and forecasting can be acquired through lightning observation. In this paper, we discuss the way to achieve instantaneous lightning signal intensification and detection from geostationary orbit by using the differences between the lightning signal and the slowly changing background noise such as that of cloud, land and ocean, combining three methods, spectral filtering, spatial filtering and background noise, enabling removal between frames. After six months of operation in orbit, lightning within the coverage of the Geostationary Lightning Imager was effectively detected, strongly supporting the case for shorttime and real-time early warning, forecasting and tracking of severe convective phenomena in China.展开更多
This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on ...This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.展开更多
发作性、短暂性、重复性、刻板性是癫痫发作的共性特征,而具有以上特征的并非都是癫痫发作,还可见于其他发作性疾病,需结合其发作时的临床表现及脑电图(EEG)特征等进行鉴别诊断。语言障碍可见于多种疾病,只表现为语言障碍的癫痫发作报...发作性、短暂性、重复性、刻板性是癫痫发作的共性特征,而具有以上特征的并非都是癫痫发作,还可见于其他发作性疾病,需结合其发作时的临床表现及脑电图(EEG)特征等进行鉴别诊断。语言障碍可见于多种疾病,只表现为语言障碍的癫痫发作报道较少,而表现为语言性发作的非惊厥持续状态(Nonconvulsive status epilepticus,NCSE)国内尚未见报道,是此种发作形式少见?还是容易被忽视误诊?现报道1例以语言性发作为表现形式的NCSF,结合影像及动态脑电图(AEEG)展开更多
A study of shock train self-excited oscillation in an isolator with background waves was implemented through a wind tunnel experiment.Dynamic pressure data were captured by high-frequency pressure measurements and the...A study of shock train self-excited oscillation in an isolator with background waves was implemented through a wind tunnel experiment.Dynamic pressure data were captured by high-frequency pressure measurements and the flow field was recorded by the high-speed Schlieren technique.The shock train structure was mostly asymmetrical during self-excited oscillation,regardless of its oscillation mode.We found that the pressure discontinuity caused by background waves was responsible for the asymmetry.On the wall where the pressure at the leading edge of the shock train was lower,a large separation region formed and the shock train deflected toward to the other wall.The oscillation mode of the shock train was related to the change of wall pressure in the oscillation range of its leading edge.The oscillation range and oscillation intensity of the shock train leading edge were affected by the wall pressure gradient induced by background waves.When located in a negative pressure gradient region,the oscillation of the leading edge strengthened;when located in a positive pressure gradient region,the oscillation weakened.To find out the cause of self-excited oscillation,correlation and phase analyses were performed.The results indicated that the instability of the separation region induced by the leading shock was the source of perturbation that caused self-excited oscillation,regardless of the oscillation mode of the shock train.展开更多
Previous studies have shown that for the Supernova Legacy Survey three-year （SNLS3） data there is strong evidence for the redshifl- evolution of color-luminosity parameter β of type Ia supernovae （SN Ia）. In this...Previous studies have shown that for the Supernova Legacy Survey three-year （SNLS3） data there is strong evidence for the redshifl- evolution of color-luminosity parameter β of type Ia supernovae （SN Ia）. In this paper, we explore the effects of varying β on the cosmological constraints of holographic dark energy （HDE） model. In addition to the SNLS3 data, we also use Planck distance prior data of cosmic microwave background （CMB）, as well as galaxy clustering （GC） data extracted from Sloan Digital Sky Survey （SDSS） data release 7 and Baryon Oscillation Spectroscopic Survey （BOSS）. We find that, for the both cases of using SN data alone and using SN＋CMB＋GC data, involving an additional parameter of β can reduce χ^2 by - 36; this shows that β deviates from a constant at 6σ- confidence levels. Adopting SN＋CMB＋GC data, we find that compared to the constant β case, varying β yields a larger fractional matter density Ωm0 and a smaller reduced Hubble constant h; moreover, varying β significantly increases the value of HDE model parameter c, leading to c ≈ 0.8, consistent with the constraint results obtained before Planck. These results indicate that the evolution of β should be taken into account seriously in the cosmological fits. In addition, we find that relative to the differences between the constant β and varying β（z） cases, the effects of different light-curve fitters on parameter estimation are very small.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10525522 and 10875129
文摘In Verlinde＇s entropic force scenario of gravity, Newton＇s laws and Einstein equations can be obtained from the first principles and general assumptions. However, the equipartition law of energy is invalid at very low temperatures. We show clearly that the threshold of the equipartition law of energy is related with horizon of the universe. Thus, a one-dimensional Debye （ODD） model in the direction of radius of the modified entropic force （MEF） may be suitable in description of the accelerated expanding universe. We present a Friedmann cosmic dynamical model in the ODD-MEF framework. We examine carefully constraints on the ODD-MEF model from the Union2 compilation of the Supernova Cosmology Project （SCP） collaboration, the data from the observation of the large-scale structure （LSS） and the cosmic microwave background （CMB）, i.e. SNe Ia＋LSS＋CMB. The combined numerical analysis gives the best-fit value of the model parameters （ -10^-9 and Ωm0= 0.224, with 2 = Xmin= 591.156. The corresponding age of the universe agrees with the result of D. Spergel et al. [J.M. Bardeen, B. Carter, and S.W. Hawking, Commun. Math. Phys. 31 （1973） 161] at 95% confidence level. The numerical result also yields an accelerated expanding universe without invoking any kind of dark energy. Taking ζ（= 2πωD/ H0 ） as a running parameter associated with the structure scale r, we obtain a possible unified scenario of the asymptotic flatness of the radial velocity dispersion of spiral galaxies, the accelerated expanding universe and the Pioneer 10/11 anomaly in the entropic force framework of Verlinde.
基金supported by the National Forestry Public Welfare Program of China (201304216)the National Key Technologies R&D Program of China (2012BAD22B04)the National Key Laboratory Projects (LFSE2015-20)
文摘This article seeks to develop a fuller understanding of the social and attraction motives of domestic tourists who visit the Changbai Mountain Biosphere Reserve(CMBR) in Northeastern China. To do so, ecotourists are compared to general travelers visiting this area. A questionnaire was employed to collect data on visitor characteristics and motivations, responses to which were then analyzed via descriptive statistics, T-tests and principal component factor analysis. Results showed that 16% of the visitors to this area were classified as ecotourists, while the remainder general travelers. Five motivations displayed significant differences(P<0.05) between these two types of tourists. Three social motives – boosting self-confidence, feeling at home away from home and being together with family – and two attraction motives – indoor sports and viewing unique landscapes of the CMBR(crater lake, waterfall, gorge and hot spring) – were significantly more important for general travelers(P<0.05); while two social motives of experiencing the tranquility of the natural setting and the natural beauty of the landscape were relatively more important for ecotourists(P<0.1). Results suggest that ecotourists have distinct and complicated attraction and social motives compared to general travelers visiting the CMBR. Results have useful implications for researchers interested in tourist motivations and behavior, as well as for managers who wish to focus their marketing strategies more effectively. National Park of South Africa. Uysal et al.(1994) assessed the travel motives of Australian tourists to U.S. national parks and nature areas and formed five groupings including ‘relaxation/hobbies', ‘novelty', ‘enhancement of kinship relationship', ‘escape', and ‘prestige'. Tao et al.(2004) analyzed motivations of Asian tourists travelling to Taiwan's Taroko National Park using a self-defined approach and found that the most significant benefits sought by self-defined ecotourists are ‘learning about nature' and ‘participating in recreation activities'. Beh and Bruyere(2007) analyzed visitor motivations in three Kenyan national reserves, identifying the three most prominent kinds of tourists as escapers, learners and spiritualists. Pan and Ryan(2007) used factor analysis to reveal five motivational dimensions –‘relaxation', ‘social needs', ‘a sense of belonging', ‘mastery skills', and ‘intellectual needs' – of visitors to the Pirongia Forest Park in New Zealand. Kruger and Saayman(2010) did a comparative study on travel motivations of tourists to Kruger and Tsitsikamma National Parks in South Africa and found that common motives of tourists were ‘escape and relaxation' as well as ‘knowledge seeking', ‘nostalgia' and ‘park attributes'. Despite these efforts, on an overall basis past literature on why visitors travel to national parks and nature areas is still rather limited. In China, a number of empirical studies on tourist motivations have been conducted since the early 1990s(Chen and Miao 2006; Dong 2011; Huang et al. 2011; Jeffrey and Xie 1994; Lu 1997; Ma et al. 2013; Zhang 2012). Some studies have focused on motivations of visitors to nature reserves(Li 2007), geological parks(Chen and Qiao 2010), world heritage sites(Su et al. 2005), and seismic memorial sites(Tang 2014). However, most previous research findings on tourist motivations are not comparable, reflecting the fact that visitors to different parks have quite different motives due to the attributes of particular destinations, the geographic locations of these parks, types of available activities, marketing strategies, and the complexity of travel motives(Chen and Qiao 2010; Pan and Ryan 2007). While it is true that certain motivations were shared in varying degrees by most tourists to these places – i.e., ‘appreciating natural landscapes', ‘family and education', ‘social needs', and ‘perceived prestige of visit' – most previous research has not focused on natural settings as destinations. Thus travel motivations of tourists to these areas must be further explored and clarified in relation to impacts on particular natural areas and patterns of market segmentation. As one of the earliest and largest natural reserves established in China, the Changbai Mountain Biosphere Reserve(CMBR) has long been a draw not only for domestic tourists but also for international visitors, and tourism to the area has been growing steadily since 1980. With the number of visitors to the reserve having climbed to 2.44 million in 2010(Statistical Communiqué of the Changbai Mountain Protection and Development Zone of Jilin Province 2011), it has become imperative for local government officials and reserve wardens to understand tourists' desires and interests when identifying tourism development opportunities. However, the existing literature still suffers from a lack of empirical studies that investigate why people travel to the CMBR and whether tourist motives differ between groups such as ecotourists and general travelers. The target population for this study consists of domestic visitors to the CMBR. The goals of this research include:(1) to identify the social and attraction motives of domestic tourists that influence decisions to visit the CMBR;(2) to explore whether there are any differences between the motivations of these two types of tourists; and(3) to provide some useful management implications for local government and tourism marketers.
基金Supported by the National Natural Science Foundation of China (No.61179016)
文摘The performance of the Ordered-Statistic Smallest Of (OSSO) Constant False Alarm Rate (CFAR) with binary integration in Weibull background with known shape parameter is analyzed, in the cases that the processor operates in homogeneous background and non-homogeneous situation caused by multiple targets and clutter edge. The analytical models of this scheme for the performance evaluation are given. It is shown that the OSSO-CFAR with binary integration can greatly improve the detection performance with respect to the single pulse processing case. As the clutter background becomes spiky, a high threshold S of binary integration (S/M) is required in order to obtain a good detection performance in homogeneous background. Moreover, the false alarm performance of the OSSO-CFAR with binary integration is more sensitive to the changes of shape parameter or power level of the clutter background.
文摘Lightning is a typical example of an instantaneous random point source target. It has close connection with severe convective phenomena such as a thunderstorm, whose distribution, variation, position and forecasting can be acquired through lightning observation. In this paper, we discuss the way to achieve instantaneous lightning signal intensification and detection from geostationary orbit by using the differences between the lightning signal and the slowly changing background noise such as that of cloud, land and ocean, combining three methods, spectral filtering, spatial filtering and background noise, enabling removal between frames. After six months of operation in orbit, lightning within the coverage of the Geostationary Lightning Imager was effectively detected, strongly supporting the case for shorttime and real-time early warning, forecasting and tracking of severe convective phenomena in China.
文摘This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.
文摘发作性、短暂性、重复性、刻板性是癫痫发作的共性特征,而具有以上特征的并非都是癫痫发作,还可见于其他发作性疾病,需结合其发作时的临床表现及脑电图(EEG)特征等进行鉴别诊断。语言障碍可见于多种疾病,只表现为语言障碍的癫痫发作报道较少,而表现为语言性发作的非惊厥持续状态(Nonconvulsive status epilepticus,NCSE)国内尚未见报道,是此种发作形式少见?还是容易被忽视误诊?现报道1例以语言性发作为表现形式的NCSF,结合影像及动态脑电图(AEEG)
基金supported by the National Natural Science Foundation of China(Nos.11972139 and 51676204)。
文摘A study of shock train self-excited oscillation in an isolator with background waves was implemented through a wind tunnel experiment.Dynamic pressure data were captured by high-frequency pressure measurements and the flow field was recorded by the high-speed Schlieren technique.The shock train structure was mostly asymmetrical during self-excited oscillation,regardless of its oscillation mode.We found that the pressure discontinuity caused by background waves was responsible for the asymmetry.On the wall where the pressure at the leading edge of the shock train was lower,a large separation region formed and the shock train deflected toward to the other wall.The oscillation mode of the shock train was related to the change of wall pressure in the oscillation range of its leading edge.The oscillation range and oscillation intensity of the shock train leading edge were affected by the wall pressure gradient induced by background waves.When located in a negative pressure gradient region,the oscillation of the leading edge strengthened;when located in a positive pressure gradient region,the oscillation weakened.To find out the cause of self-excited oscillation,correlation and phase analyses were performed.The results indicated that the instability of the separation region induced by the leading shock was the source of perturbation that caused self-excited oscillation,regardless of the oscillation mode of the shock train.
基金supported by the National Natural Science Foundation of China(Grant Nos.11405024 and 11175042)the Fundamental Research Fundsfor the Central Universities(Grant Nos.N130305007 and N120505003)
文摘Previous studies have shown that for the Supernova Legacy Survey three-year （SNLS3） data there is strong evidence for the redshifl- evolution of color-luminosity parameter β of type Ia supernovae （SN Ia）. In this paper, we explore the effects of varying β on the cosmological constraints of holographic dark energy （HDE） model. In addition to the SNLS3 data, we also use Planck distance prior data of cosmic microwave background （CMB）, as well as galaxy clustering （GC） data extracted from Sloan Digital Sky Survey （SDSS） data release 7 and Baryon Oscillation Spectroscopic Survey （BOSS）. We find that, for the both cases of using SN data alone and using SN＋CMB＋GC data, involving an additional parameter of β can reduce χ^2 by - 36; this shows that β deviates from a constant at 6σ- confidence levels. Adopting SN＋CMB＋GC data, we find that compared to the constant β case, varying β yields a larger fractional matter density Ωm0 and a smaller reduced Hubble constant h; moreover, varying β significantly increases the value of HDE model parameter c, leading to c ≈ 0.8, consistent with the constraint results obtained before Planck. These results indicate that the evolution of β should be taken into account seriously in the cosmological fits. In addition, we find that relative to the differences between the constant β and varying β（z） cases, the effects of different light-curve fitters on parameter estimation are very small.
