Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP) in a greenhouse compartment in midwinter at latitude 59° n...Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP) in a greenhouse compartment in midwinter at latitude 59° north. The study included 10 different treatments and six rose cultivars, altogether 900 plants. The 16 and 20 h LP were applied with or without a dark period of 8 and 4 h·day-1, respectively, by timing the LP in relation to daylight that lasted for 7 - 8 h. Number of days until flowering decreased with an increase in PFD and in LP up to 24 day-1 and was unaffected by the timing of the 16 and 20 h·day-1 LP. Number of flowers and plant dry weight increased 20% to 30% by increasing the PFD. Plant dry weight increased by increasing the LP from 16 to 20 h·day-1 (about 25%), but no effect was found with a further increase to 24 h·day-1. Mean growth rate until flowering increased 30% to 40% by increasing the PFD or by increasing the LP from 16 to 20 h day-1, while little effect was found by a further increase to 24 h·day-1. Increasing the photosynthetic active radiation (PAR) by increasing the LP from 16 to 20 h·day-1 increased the growth rate more than increasing the PFD did. Three of the cultivars were tested for water loss after the detachment of some leaves. Leaves that had developed without a dark period showed a considerably higher water loss than the treatments that included a dark period of 4 or 8 h·day-1. The keeping quality at indoor conditions, however, was unaffected by the treatment due to sufficient watering. Powdery mildew developed significantly more on plants grown with a dark period of 8 h as compared with the other treatments. It was concluded that 20 h·day-1 LP including a dark period of 4 h·day-1 and a PFD of at least 150 μmol·m-2·s-1 should be applied to miniature roses during the winter months in order to effectively produce miniature pot roses with a high quality.展开更多
Observational evidence of unstable behavior for the W UMa type binary system V1073 Cygni is presented in this paper. Around 1939 the period of the binary suddenly decreased by 0 580 seconds and again suddenly decrease...Observational evidence of unstable behavior for the W UMa type binary system V1073 Cygni is presented in this paper. Around 1939 the period of the binary suddenly decreased by 0 580 seconds and again suddenly decreased by 0 746 seconds around 1981.Obvious variable O’ Connell effect of the light curves in V can be seen. The relation between the changes in the orbital period and variation in the O’ Connell effect and possible reasons for the unstable behavior of V1073 Cyg were discussed.展开更多
In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cell...In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cells. According to the framework of the Reyleigh-Sommerfeld diffraction algorithm and the experimental results of random morphologies, we analyze the light-scattering properties of four superimposing morphologies and compare them with the individual morphologies in detail. The results indicate that the superimposing morphology can offer a better light trapping capacity, owing to the coexistence of the random scattering mechanism and the periodic scattering mechanism. Its scattering property will be dominated by the individual nanostructures whose geometrical features play the leading role.展开更多
Based on the practical situation of nondestructive examination, the calculation model of the composite scattering is established by using a three-dimensional half-space finite difference time domain, and the Monte Car...Based on the practical situation of nondestructive examination, the calculation model of the composite scattering is established by using a three-dimensional half-space finite difference time domain, and the Monte Carlo method is used to solve the problem of the optical surface with roughness in the proposed scheme. Moreover, the defect particles are observed as periodic particles for a more complex situation. In order to obtain the scattering contribution of defects inside the optical surface, a difference radar cross section is added into the model to analyze the selected calculations on the effects of numbers, separation distances, different depths and different materials of defects. The effects of different incident angles are also discussed. The numerical results are analyzed in detail to demonstrate the best position to find the defects in the optical surface by detecting in steps of a fixed degree for the incident angle.展开更多
The principal circadian clock in the suprachiasm nucleus （SCN） regulates the circadian rhythm of physiological and behavioral activities of mammals. Except for the normal function of the circadian rhythm, the ensemb...The principal circadian clock in the suprachiasm nucleus （SCN） regulates the circadian rhythm of physiological and behavioral activities of mammals. Except for the normal function of the circadian rhythm, the ensemble of SCN neurons may show two collective behaviors, i.e., a free running period in the absence of a light-dark cycle and an entrainment ability to an external T cycle. Experiments show that both the free running periods and the entrainment ranges may vary from one species to another and can be seriously influenced by the coupling among the SCN neurons. We here review the recent progress on how the heterogeneous couplings influence these two collective behaviors. We will show that in the case of homogeneous coupling, the free running period increases monotonically while the entrainment range decreases monotonically with the increase of the coupling strength. While in the case of heterogenous coupling, the dispersion of the coupling strength plays a crucial role. It has been found that the free running period decreases with the increase of the dispersion while the entrainment ability is enhanced by the dispersion. These findings provide new insights into the mechanism of the circadian clock in the SCN.展开更多
[Objective] The characteristics of thermal climate resources changes of agricultural production during frost period in Jianchang County were studied. [Method] By dint of Jianchang climate resources and routine numeric...[Objective] The characteristics of thermal climate resources changes of agricultural production during frost period in Jianchang County were studied. [Method] By dint of Jianchang climate resources and routine numerical statistics method, the sunlight and temperature changes trend from 1960 to 2009 in Jianchang County were analyzed. [Result] The sunshine hours and sunshine percentages during frost period in Janchang County from 1960 to 2009 tended to decrease. The climate tendency rates were -55.556 h/10 a and -2.39%/10 a respectively, 287 h and 12% of deduction in recent 50 years. There were climate transition in 1981 and 1982. And there were a shortage of 161 h and 7% of sunshine hours and sunshine percentages before and after the transition. The temperature during the frost period generally was increasing. The average temperature, average maximum and lowest temperature tendency rate were 0.386, 0.392 and 0.567 ℃/10 a. There was a growth of 1.93, 1.96 and 2.84 ℃ in recent 50 years. There were temperature transition in 1987 and 1988. The average temperature, average maximum and lowest temperature increased 1.3, 1.2 and 1.7 ℃. In recent 50 years, the sunshine resources during frost period in Jianchang were decreasing, while the thermal resources were strengthening, forming complementary of light and heat. [Conclusion] The study provided climate accordance to the development of local facility agriculture during frost period.展开更多
文摘Miniature roses (Rosa sp.) were grown at 100 and 150 μmol m-2·s-1 photon flux densities (PFD) with 16, 20 and 24 h·day-1 lighting periods (LP) in a greenhouse compartment in midwinter at latitude 59° north. The study included 10 different treatments and six rose cultivars, altogether 900 plants. The 16 and 20 h LP were applied with or without a dark period of 8 and 4 h·day-1, respectively, by timing the LP in relation to daylight that lasted for 7 - 8 h. Number of days until flowering decreased with an increase in PFD and in LP up to 24 day-1 and was unaffected by the timing of the 16 and 20 h·day-1 LP. Number of flowers and plant dry weight increased 20% to 30% by increasing the PFD. Plant dry weight increased by increasing the LP from 16 to 20 h·day-1 (about 25%), but no effect was found with a further increase to 24 h·day-1. Mean growth rate until flowering increased 30% to 40% by increasing the PFD or by increasing the LP from 16 to 20 h day-1, while little effect was found by a further increase to 24 h·day-1. Increasing the photosynthetic active radiation (PAR) by increasing the LP from 16 to 20 h·day-1 increased the growth rate more than increasing the PFD did. Three of the cultivars were tested for water loss after the detachment of some leaves. Leaves that had developed without a dark period showed a considerably higher water loss than the treatments that included a dark period of 4 or 8 h·day-1. The keeping quality at indoor conditions, however, was unaffected by the treatment due to sufficient watering. Powdery mildew developed significantly more on plants grown with a dark period of 8 h as compared with the other treatments. It was concluded that 20 h·day-1 LP including a dark period of 4 h·day-1 and a PFD of at least 150 μmol·m-2·s-1 should be applied to miniature roses during the winter months in order to effectively produce miniature pot roses with a high quality.
文摘Observational evidence of unstable behavior for the W UMa type binary system V1073 Cygni is presented in this paper. Around 1939 the period of the binary suddenly decreased by 0 580 seconds and again suddenly decreased by 0 746 seconds around 1981.Obvious variable O’ Connell effect of the light curves in V can be seen. The relation between the changes in the orbital period and variation in the O’ Connell effect and possible reasons for the unstable behavior of V1073 Cyg were discussed.
基金Project supported by the National Basic Research Program of China （Grant Nos. 2011CBA00705, 2011CBA00706, and 2011CBA00707）, the National Natural Science Foundation of China （Grant No. 61377031）, the Natural Science Foundation of Tianjin, China （Grant No. 12JCQNJC01000）, the Specialized Research Fund for the Doctoral Program of Higher Education, China （Grant No. 20120031120044）, and the Fundamental Research Funds for the Central Universities, China （Grant No. 65012371）.
文摘In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cells. According to the framework of the Reyleigh-Sommerfeld diffraction algorithm and the experimental results of random morphologies, we analyze the light-scattering properties of four superimposing morphologies and compare them with the individual morphologies in detail. The results indicate that the superimposing morphology can offer a better light trapping capacity, owing to the coexistence of the random scattering mechanism and the periodic scattering mechanism. Its scattering property will be dominated by the individual nanostructures whose geometrical features play the leading role.
基金supported by the National Natural Science Foundation of China(Grant Nos.61308071,61601355,and 61571355)the Natural Science Foundation of Shaanxi Province,China(Grant No.2016JM6011)
文摘Based on the practical situation of nondestructive examination, the calculation model of the composite scattering is established by using a three-dimensional half-space finite difference time domain, and the Monte Carlo method is used to solve the problem of the optical surface with roughness in the proposed scheme. Moreover, the defect particles are observed as periodic particles for a more complex situation. In order to obtain the scattering contribution of defects inside the optical surface, a difference radar cross section is added into the model to analyze the selected calculations on the effects of numbers, separation distances, different depths and different materials of defects. The effects of different incident angles are also discussed. The numerical results are analyzed in detail to demonstrate the best position to find the defects in the optical surface by detecting in steps of a fixed degree for the incident angle.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11135001 and 11375066)the Joriss Project,China (Grant No. 78230050)the National Basic Research Program of China (Grant No. 2013CB834100)
文摘The principal circadian clock in the suprachiasm nucleus （SCN） regulates the circadian rhythm of physiological and behavioral activities of mammals. Except for the normal function of the circadian rhythm, the ensemble of SCN neurons may show two collective behaviors, i.e., a free running period in the absence of a light-dark cycle and an entrainment ability to an external T cycle. Experiments show that both the free running periods and the entrainment ranges may vary from one species to another and can be seriously influenced by the coupling among the SCN neurons. We here review the recent progress on how the heterogeneous couplings influence these two collective behaviors. We will show that in the case of homogeneous coupling, the free running period increases monotonically while the entrainment range decreases monotonically with the increase of the coupling strength. While in the case of heterogenous coupling, the dispersion of the coupling strength plays a crucial role. It has been found that the free running period decreases with the increase of the dispersion while the entrainment ability is enhanced by the dispersion. These findings provide new insights into the mechanism of the circadian clock in the SCN.
文摘[Objective] The characteristics of thermal climate resources changes of agricultural production during frost period in Jianchang County were studied. [Method] By dint of Jianchang climate resources and routine numerical statistics method, the sunlight and temperature changes trend from 1960 to 2009 in Jianchang County were analyzed. [Result] The sunshine hours and sunshine percentages during frost period in Janchang County from 1960 to 2009 tended to decrease. The climate tendency rates were -55.556 h/10 a and -2.39%/10 a respectively, 287 h and 12% of deduction in recent 50 years. There were climate transition in 1981 and 1982. And there were a shortage of 161 h and 7% of sunshine hours and sunshine percentages before and after the transition. The temperature during the frost period generally was increasing. The average temperature, average maximum and lowest temperature tendency rate were 0.386, 0.392 and 0.567 ℃/10 a. There was a growth of 1.93, 1.96 and 2.84 ℃ in recent 50 years. There were temperature transition in 1987 and 1988. The average temperature, average maximum and lowest temperature increased 1.3, 1.2 and 1.7 ℃. In recent 50 years, the sunshine resources during frost period in Jianchang were decreasing, while the thermal resources were strengthening, forming complementary of light and heat. [Conclusion] The study provided climate accordance to the development of local facility agriculture during frost period.
