In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 count...In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 countries from 2012 to 2018 to empirically examine the green effect of NEVP.The results indicate the following:(1)NEVP significantly reduces greenhouse gases emissions,and the green effect can be transmitted and diffused through a direct path.(2)Replacing fuel-fired vehicles and accelerating the end-of-life vehicle scrapping process significantly conducted the green effect,and aggravating traffic congestion was not statistically significant.(3)The transmission mechanism of the green effect is regulated by regional economic heterogeneity.In regions with better development of fuel-fired vehicles,the transmission of the green effect is subject to the elimination of fuel-fired vehicles and traffic congestion governance,and the transmission efficiency is low.However,regions with a relatively weak fuel-fired automobile industry foundation show a strong“advantage of backwardness”,and the green effect is more prominent.This means that global NEVP should be further accelerated to achieve the green effect and the goal of global carbon neutrality.展开更多
Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic ...Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic change. This paper, based on the provincial panel data from 2006 to 2015, uses super SBM model to measure the green innovation efficiency of China's tourism industry.The threshold regression model is employed to conduct empirical tests of the nonlinear threshold effect of agglomeration on the green innovation efficiency of tourism industry. The inter-provincial differences of various threshold effects and their possible causes are analyzed. Results indicate that the green innovation efficiency of China's tourism industry is generally growing, while regional disparity is significant with a gradient decrease along the eastern-central-western regions. There is an obvious positive nonlinear relationship between tourism agglomeration and green innovation efficiency. It is also found that with the increase of agglomeration, its influence is at a high level. As the level of agglomeration crosses the first threshold, its impact is at a low level, and when it crosses the second threshold, the impact of tourism agglomeration is at an intermediate level. Finally, this paper proposes the basic path and some policy recommendations to promote the green innovation efficiency of the tourism industry in China.展开更多
This paper presents the catalytic effects of Cu-Co~* catalyst on the decomposition of AN and AN/KDN based oxidizer and propellant samples. Ozawa-Flynn-Wall(OFW) iso-conversional method was used for the kinetic studies...This paper presents the catalytic effects of Cu-Co~* catalyst on the decomposition of AN and AN/KDN based oxidizer and propellant samples. Ozawa-Flynn-Wall(OFW) iso-conversional method was used for the kinetic studies and to compute the activation energy(Ea) values for various decomposition steps of the prepared oxidizer and propellant samples in the temperature range of 50 e500C. TG-DTG experiments were carried out for both oxidizer and propellant samples at the heating rates of 3, 5, and 10C/min. AN/KDN based oxidizer samples were prepared by an evaporative co-crystallization method. Citric acid sol-gel method was used for the synthesis of Cu-Co~* catalyst. The propellant sample contains HTPB as the fuel binder along with other ingredients such as TDI, DOA, and Glycerol. The Cu-Co~* catalyst was used as 2% by weight to the total weight of catalyzed oxidizer and propellant samples. It was observed from the present study that, Cu-Co~* catalyst helps in reducing the Ea values for AN and AN based propellant samples. However, with the percentage increment of KDN in the AN crystals, Ea value increases.Further, it was observed that Cu-Co~* catalyst stabilizes the initial partial decomposition of KDN.展开更多
In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observcd that the incidcnce (16.0%) of lung carcinomas was lowel, and the survival time (376 days) of...In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observcd that the incidcnce (16.0%) of lung carcinomas was lowel, and the survival time (376 days) of the first case of carcinoma and the mean survival time (758 days) of the rats with carcinoma were higher in the group of rats drinking 2% green tea extract for life than in the positive group (without drinking green tea extract). The mortality ratio (0.5047) was smaller in the cxperimental group than in the positive control group, and the survival curve of the experimental group significantly raised up, in comparison with the positive group.展开更多
The knowledge of contemporary climatic change over the Qinghai Xizang (Tibet) Plateau (QXP) has been inadequate for a long time due to lack of enough observational data. In this paper, on the basis of monthly tempera...The knowledge of contemporary climatic change over the Qinghai Xizang (Tibet) Plateau (QXP) has been inadequate for a long time due to lack of enough observational data. In this paper, on the basis of monthly temperature and precipitation data in 1961-1990 from 48 stations on the QXP, the temperature data are extended backward to 1901 with an empirical orthogonal function (EOF) method, microscopic characteristics of contemporary climatic change over the QXP are analyzed, and the response of the plateau climate to global warming is discussed in combination with atmospheric general circulation model (GCM) outputs. The results show that the plateau climate, as a whole, has been warming since the early part of this century, that the precipitation has generally been increasing during the recent 30 years, and that these climatic trends seem to be related to the enhanced green house effect induced by increasing CO 2 concentration in the atmosphere.展开更多
Analyzing the thermal distribution on plane conditions objectively is difficult due to lack of enough meteorological observation stations within urban residential areas. In this paper satellite observations synchronou...Analyzing the thermal distribution on plane conditions objectively is difficult due to lack of enough meteorological observation stations within urban residential areas. In this paper satellite observations synchronous or quasi-synchronous with ground observations are adopted, and a teleconnection model is built between the satellite spectral and surface temperature for quantitative retrieval of temperature. Furthermore, by combining the satellite data with other multiple factors, a GIS comprehensive analysis model and a functional evaluation method for urban residential districts are established, which are used to study the relation between the air temperature and media characteristics on ground as well as the greening cooling effect in recent years in Shanghai. The results show that the air temperature in greened urban residential districts is generally lower than the average temperature and much less than the highest one. In general,the average air temperature in the greened area is at most 1.19℃ lower than the maximum temperature in the districts,which is 0.67℃ and 0.55℃ lower than that of the highest for buildings and roads respectively. The temperature is inversely proportional with greening fraction but is directly proportional with the ratio of roads and buildings. The higher the greening fraction in internal residential districts, the lower the temperature, and the higher the ratio of road and building is, the higher the temperature.展开更多
A series of measurements showed that community greening and trees shading had different degree of cooling effect. The cooling effect of wall greening was related to factors such as heat storage capacity and the orient...A series of measurements showed that community greening and trees shading had different degree of cooling effect. The cooling effect of wall greening was related to factors such as heat storage capacity and the orientation of the wall, climatic conditions. As compared to the heat reduced by sheltering the solar radiation, the heat absorbed by plant transpiration had greater cooling contribution. Comprehensive considering environment, technology and economics factors, the building district greening should take trees as the priority. The trees shading can significantly drop indoor temperature and temperature fluctuation, also created better condition for night-time natural ventilation.展开更多
ZnO nanopowder is successfully synthesized by annealing the precursors in oxygen gas using the chemical precipitation method. Structural and optical properties of thus synthesized ZnO nanopowder are characterized by s...ZnO nanopowder is successfully synthesized by annealing the precursors in oxygen gas using the chemical precipitation method. Structural and optical properties of thus synthesized ZnO nanopowder are characterized by scanning electron microscopy （SEM） and photoluminescence （PL）. The morphology of ZnO nanopowders evolves from nanorod to cobble as annealing temperature increases from 500 to 1000℃, while spiral structures are observed in the samples annealed at 900 and 1000℃. The PL spectra of ZnO nanopowder consist of largely green and yellow emission bands. The green emission from ZnO nanopowder depends strongly on the annealing temperature with a peak intensity at a temperature lower than 800℃ while the yellow emission is associated with interstitial oxygen Oi.展开更多
In GaN-based green light-emitting diodes（LEDs） with different green quantum well numbers grown on Si（111）substrates by metal organic chemical vapor deposition are investigated. It is observed that V-shaped pits ap...In GaN-based green light-emitting diodes（LEDs） with different green quantum well numbers grown on Si（111）substrates by metal organic chemical vapor deposition are investigated. It is observed that V-shaped pits appear in the AFM images with the green quantum well number increasing from 5 to 9, and results in larger reverse-bias leakage current. Meanwhile, in the case of the sample with the number from 5 to 7 then to 9, the external quantum efficiency increases firstly, and then decreases. These phenomena may be related to the size of V-shaped pits in the active area and the distribution of electrons and holes in the active area caused by V-shaped pits. The optimal number of green quantum wells is determined to be 7.展开更多
The present study aimed at clarifying whether Chinese green tea, coffee and levamisole (LMS) have similar Inhibitory effect on hepatocarclnogenesis induced by diethylnltrosamine (DEN) as they had been proved in our pr...The present study aimed at clarifying whether Chinese green tea, coffee and levamisole (LMS) have similar Inhibitory effect on hepatocarclnogenesis induced by diethylnltrosamine (DEN) as they had been proved in our previous aflatoxin B1 (AFB1) experiments. Male Wistar rates were divided into control (A), green tea (B), coffee (C) and levamisole (D) groups. All rats received the same basic DEN treatment according to the program originally designed by Solt and Farber. During the two weeks before and one week after i. p. injection of DEN, the group B, C and D were given 2. 5% green tea, 5% coffee and 0. 1% LMS diet, respectively. The results demonstrated that coffee, LMS and , in particular,green tea showed Inhibitory effect against DEN-induced hepatocarcinogenesis, indicating that green tea can be used as chemopreventive agent for DEN-, as well as for AFB1-induced hepatocarcinogenesis.展开更多
The paper introduces the lemon effect of green agricultural products,analyzes the formation reasons of the lemon effect of green agricul-tural products and summarizes problems brought by the effect,such as malicious d...The paper introduces the lemon effect of green agricultural products,analyzes the formation reasons of the lemon effect of green agricul-tural products and summarizes problems brought by the effect,such as malicious deception and high price.The paper proposes countermeasures toavoid the lemon effect of green agricultural products from a perspective of marketing.The first is to strengthen the quality supervision of green agri-cultural products,upgrade the quality of products,and build up branded products.The government should foster the main body of the products andguide the main body to realize the importance of brand construction and management.The second is to construct a sales channel system of greenagricultural products,making use of the trading center of modern green agricultural products to sell products,developing a long term partnershipwith processing industries,big supermarket and restaurants,making use of internet and selling products online and offline.The third is to propagatethe products.Make a good use of advertisement,personal sales,propagation and public relations to accelerate the healthy development of greenagricultural market.展开更多
As one of the important parts of urban ecosystem, urban green space plays an irreplaceable role in maintaining the balance of carbon and oxygen, absorbing the pollution and removing dust, killing bacteria, purifying s...As one of the important parts of urban ecosystem, urban green space plays an irreplaceable role in maintaining the balance of carbon and oxygen, absorbing the pollution and removing dust, killing bacteria, purifying soil and water. To analyze the spatio-temporal changes of humidifying effect of green lands at the spring daytime, the authors monitored the air humidity within 1.8 m high from various underlying surfaces, including arbor-grass lands, shrub lands, herb lands and a cement pavement, from late February to late April in 2015 and 2016, when it was sunny and windless, in the Yuxi park of Shijiazhuang. The results were compared with the monitoring data of a bare land(190 m×120 m) without environmental interventions such as vegetation and water. The results could be summarized as follows:(1) The humidifying effect of green spaces was the weakest at 8:00 a.m. during the late February, whereas it was the strongest at 10:00 a.m.; from late March to late April, the humidifying effect of green spaces strengthened with the increase of air temperature, and the strongest was noted around 12:00-16:00.(2) The humidifying effect of various types of green lands was the strongest close to the ground, and reduced from 0.2 m to 1.8 m. This vertical stratification became apparent after the plants sprouted, the vertical difference of humidifying effect was the most significant in the herb lands, less significant in arbor-grass lands, and least in the shrub lands.(3) Multiple comparison analysis of the humidity data showed that relative humidity of all green lands achieved the significant level(P < 0.05), indicating the strong effect of landscape plants in adjusting atmospheric humidity in spring.(4) The humidifying effect of the artificial lake was more remarkable before the plants sprouted, however, with the rapid growth of plant leaves, theeffect gradually reduced and became even weaker than the effect of vegetation. Although the humidifying effect in spring was weaker than that in summer and autumn, the effect of humidification was more complicated during the growth of green leaves in spring than in summer and autumn. This is useful to construct the theory system of ecological environment effect of green lands in spring, summer and autumn.展开更多
We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zha...We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zhaiye- qing 8),96E80[(IR 24/Guanglu＇ai 4//Zhongnan’ai)/Yifengzao],96E86(Zhong- munong 9/Zhaiyeqing 8).The induction mediaused was M8+2mg/L 2,4-D,and agar con-centrations were 0.6％,0.8％,and 1.0％,respectively.Regeneration media was MS+2mg/L KT+0.5mg/L IAA+0.5mg/LNAA,and agar concentrations were 0.6％ and1.0％.Results indicated that the calli induc-展开更多
The accelerating urbanization process and intensifying climate change have exacerbated the urban heat island effect, threatening sustainable urban development. This study investigates the role of green infrastructure ...The accelerating urbanization process and intensifying climate change have exacerbated the urban heat island effect, threatening sustainable urban development. This study investigates the role of green infrastructure in mitigating urban heat island effects, its implementation challenges, and applications. Employing a system dynamics approach, the research models the relationships between green infrastructure, urban microclimate, and human well-being. Findings indicate that large, continuous green spaces, such as urban parks and green corridors, are most effective, potentially reducing surrounding temperatures by 1˚C - 4˚C. Green infrastructure also provides multiple ecosystem services, including improved air quality and increased biodiversity. However, its implementation faces challenges such as land resource limitations and financial constraints. To address these issues, the study proposes a performance-based planning method, emphasizing multifunctional design and cross-sectoral collaboration. Through analysis of international and Chinese urban case studies, best practices and lessons learned are summarized. The research demonstrates that successful strategies must be context-specific, integrating local conditions while emphasizing long-term planning and continuous optimization. This study provides a scientific basis for developing effective heat island mitigation strategies and climate adaptation plans, ultimately achieving sustainable urban development and improved living environments.展开更多
Wild rice is an important resource of usefulgenes to rice breeders. However, low regener-ation frequency is an obstacle to use the valu-able genes. We used desiccation to improve theregeneration frequency and studied ...Wild rice is an important resource of usefulgenes to rice breeders. However, low regener-ation frequency is an obstacle to use the valu-able genes. We used desiccation to improve theregeneration frequency and studied the bio-chemical changes of calli of wild rice after des-iccation.Materials used in this experiment werewild species O. rufipogon, O. meyeriana, O.alta, and O. brachyantha. Young panicles(0.1-0. 5 cm in length of the inflorescence)展开更多
A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes thr...A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes three elastic constants of single cubic crystal and ?ve texture coe?cients, accounts for the e?ects of the orientation distribution function (ODF) up to terms linear in the tex- ture coe?cients. Thus it is expected that our formula would be applicable to arbitrary aggregates with weak texture or to materials such as aluminum whose single crystal has weak anisotropy. Three examples are presented to compare predictions from our formula with those from Nishioka and Lothe’s formula and Synge’s contour integral through numerical integration. As an applica- tion of Green’s function, we brie?y describe the procedure of deriving the e?ective elastic sti?ness tensor for an orthorhombic aggregate of cubic crystallites. The comparison of the computational results given by the ?nite element method and our e?ective elastic sti?ness tensor is made by an example.展开更多
The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence propert...The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.展开更多
文摘In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 countries from 2012 to 2018 to empirically examine the green effect of NEVP.The results indicate the following:(1)NEVP significantly reduces greenhouse gases emissions,and the green effect can be transmitted and diffused through a direct path.(2)Replacing fuel-fired vehicles and accelerating the end-of-life vehicle scrapping process significantly conducted the green effect,and aggravating traffic congestion was not statistically significant.(3)The transmission mechanism of the green effect is regulated by regional economic heterogeneity.In regions with better development of fuel-fired vehicles,the transmission of the green effect is subject to the elimination of fuel-fired vehicles and traffic congestion governance,and the transmission efficiency is low.However,regions with a relatively weak fuel-fired automobile industry foundation show a strong“advantage of backwardness”,and the green effect is more prominent.This means that global NEVP should be further accelerated to achieve the green effect and the goal of global carbon neutrality.
基金supported by National Social Science Foundation of China "Quality of China's Tourism Economic Growth and Its Spatial Analysis"[Grant number:17FGL005]Social Science Planning Fund Program of Shandong Province "Research on the Mechanism of Dynamic Energy Conversion to Promote the Optimization of Tourism Industrial Structure in Shandong Province"[Grant Number:17CLYJ40]Social Science Planning Fund Program of Qingdao City "The Way of Improving the Quality of Tourism Economic Growth in Qingdao"[Grant Number:QDSKLl701014]
文摘Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic change. This paper, based on the provincial panel data from 2006 to 2015, uses super SBM model to measure the green innovation efficiency of China's tourism industry.The threshold regression model is employed to conduct empirical tests of the nonlinear threshold effect of agglomeration on the green innovation efficiency of tourism industry. The inter-provincial differences of various threshold effects and their possible causes are analyzed. Results indicate that the green innovation efficiency of China's tourism industry is generally growing, while regional disparity is significant with a gradient decrease along the eastern-central-western regions. There is an obvious positive nonlinear relationship between tourism agglomeration and green innovation efficiency. It is also found that with the increase of agglomeration, its influence is at a high level. As the level of agglomeration crosses the first threshold, its impact is at a low level, and when it crosses the second threshold, the impact of tourism agglomeration is at an intermediate level. Finally, this paper proposes the basic path and some policy recommendations to promote the green innovation efficiency of the tourism industry in China.
文摘This paper presents the catalytic effects of Cu-Co~* catalyst on the decomposition of AN and AN/KDN based oxidizer and propellant samples. Ozawa-Flynn-Wall(OFW) iso-conversional method was used for the kinetic studies and to compute the activation energy(Ea) values for various decomposition steps of the prepared oxidizer and propellant samples in the temperature range of 50 e500C. TG-DTG experiments were carried out for both oxidizer and propellant samples at the heating rates of 3, 5, and 10C/min. AN/KDN based oxidizer samples were prepared by an evaporative co-crystallization method. Citric acid sol-gel method was used for the synthesis of Cu-Co~* catalyst. The propellant sample contains HTPB as the fuel binder along with other ingredients such as TDI, DOA, and Glycerol. The Cu-Co~* catalyst was used as 2% by weight to the total weight of catalyzed oxidizer and propellant samples. It was observed from the present study that, Cu-Co~* catalyst helps in reducing the Ea values for AN and AN based propellant samples. However, with the percentage increment of KDN in the AN crystals, Ea value increases.Further, it was observed that Cu-Co~* catalyst stabilizes the initial partial decomposition of KDN.
文摘In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observcd that the incidcnce (16.0%) of lung carcinomas was lowel, and the survival time (376 days) of the first case of carcinoma and the mean survival time (758 days) of the rats with carcinoma were higher in the group of rats drinking 2% green tea extract for life than in the positive group (without drinking green tea extract). The mortality ratio (0.5047) was smaller in the cxperimental group than in the positive control group, and the survival curve of the experimental group significantly raised up, in comparison with the positive group.
文摘The knowledge of contemporary climatic change over the Qinghai Xizang (Tibet) Plateau (QXP) has been inadequate for a long time due to lack of enough observational data. In this paper, on the basis of monthly temperature and precipitation data in 1961-1990 from 48 stations on the QXP, the temperature data are extended backward to 1901 with an empirical orthogonal function (EOF) method, microscopic characteristics of contemporary climatic change over the QXP are analyzed, and the response of the plateau climate to global warming is discussed in combination with atmospheric general circulation model (GCM) outputs. The results show that the plateau climate, as a whole, has been warming since the early part of this century, that the precipitation has generally been increasing during the recent 30 years, and that these climatic trends seem to be related to the enhanced green house effect induced by increasing CO 2 concentration in the atmosphere.
基金Key Project of Shanghai Science Committee(10511501700)(Lingang New Town)Special Project for Key Marine Science and Technology of Shanghai Science Committee(10dz1210802)
文摘Analyzing the thermal distribution on plane conditions objectively is difficult due to lack of enough meteorological observation stations within urban residential areas. In this paper satellite observations synchronous or quasi-synchronous with ground observations are adopted, and a teleconnection model is built between the satellite spectral and surface temperature for quantitative retrieval of temperature. Furthermore, by combining the satellite data with other multiple factors, a GIS comprehensive analysis model and a functional evaluation method for urban residential districts are established, which are used to study the relation between the air temperature and media characteristics on ground as well as the greening cooling effect in recent years in Shanghai. The results show that the air temperature in greened urban residential districts is generally lower than the average temperature and much less than the highest one. In general,the average air temperature in the greened area is at most 1.19℃ lower than the maximum temperature in the districts,which is 0.67℃ and 0.55℃ lower than that of the highest for buildings and roads respectively. The temperature is inversely proportional with greening fraction but is directly proportional with the ratio of roads and buildings. The higher the greening fraction in internal residential districts, the lower the temperature, and the higher the ratio of road and building is, the higher the temperature.
文摘A series of measurements showed that community greening and trees shading had different degree of cooling effect. The cooling effect of wall greening was related to factors such as heat storage capacity and the orientation of the wall, climatic conditions. As compared to the heat reduced by sheltering the solar radiation, the heat absorbed by plant transpiration had greater cooling contribution. Comprehensive considering environment, technology and economics factors, the building district greening should take trees as the priority. The trees shading can significantly drop indoor temperature and temperature fluctuation, also created better condition for night-time natural ventilation.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 70234040, 60476040 and 60576068)the Shanghai Science and Technology Foundation, China (Grant No 05DJ14003)
文摘ZnO nanopowder is successfully synthesized by annealing the precursors in oxygen gas using the chemical precipitation method. Structural and optical properties of thus synthesized ZnO nanopowder are characterized by scanning electron microscopy （SEM） and photoluminescence （PL）. The morphology of ZnO nanopowders evolves from nanorod to cobble as annealing temperature increases from 500 to 1000℃, while spiral structures are observed in the samples annealed at 900 and 1000℃. The PL spectra of ZnO nanopowder consist of largely green and yellow emission bands. The green emission from ZnO nanopowder depends strongly on the annealing temperature with a peak intensity at a temperature lower than 800℃ while the yellow emission is associated with interstitial oxygen Oi.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0400601the National Natural Science Foundation of China under Grant Nos 61704069,11674147,61604066,51602141 and 11604137
文摘In GaN-based green light-emitting diodes（LEDs） with different green quantum well numbers grown on Si（111）substrates by metal organic chemical vapor deposition are investigated. It is observed that V-shaped pits appear in the AFM images with the green quantum well number increasing from 5 to 9, and results in larger reverse-bias leakage current. Meanwhile, in the case of the sample with the number from 5 to 7 then to 9, the external quantum efficiency increases firstly, and then decreases. These phenomena may be related to the size of V-shaped pits in the active area and the distribution of electrons and holes in the active area caused by V-shaped pits. The optimal number of green quantum wells is determined to be 7.
文摘The present study aimed at clarifying whether Chinese green tea, coffee and levamisole (LMS) have similar Inhibitory effect on hepatocarclnogenesis induced by diethylnltrosamine (DEN) as they had been proved in our previous aflatoxin B1 (AFB1) experiments. Male Wistar rates were divided into control (A), green tea (B), coffee (C) and levamisole (D) groups. All rats received the same basic DEN treatment according to the program originally designed by Solt and Farber. During the two weeks before and one week after i. p. injection of DEN, the group B, C and D were given 2. 5% green tea, 5% coffee and 0. 1% LMS diet, respectively. The results demonstrated that coffee, LMS and , in particular,green tea showed Inhibitory effect against DEN-induced hepatocarcinogenesis, indicating that green tea can be used as chemopreventive agent for DEN-, as well as for AFB1-induced hepatocarcinogenesis.
文摘The paper introduces the lemon effect of green agricultural products,analyzes the formation reasons of the lemon effect of green agricul-tural products and summarizes problems brought by the effect,such as malicious deception and high price.The paper proposes countermeasures toavoid the lemon effect of green agricultural products from a perspective of marketing.The first is to strengthen the quality supervision of green agri-cultural products,upgrade the quality of products,and build up branded products.The government should foster the main body of the products andguide the main body to realize the importance of brand construction and management.The second is to construct a sales channel system of greenagricultural products,making use of the trading center of modern green agricultural products to sell products,developing a long term partnershipwith processing industries,big supermarket and restaurants,making use of internet and selling products online and offline.The third is to propagatethe products.Make a good use of advertisement,personal sales,propagation and public relations to accelerate the healthy development of greenagricultural market.
基金Supported by the National Science and Technology Major Project(2011ZX05043-005)
文摘As one of the important parts of urban ecosystem, urban green space plays an irreplaceable role in maintaining the balance of carbon and oxygen, absorbing the pollution and removing dust, killing bacteria, purifying soil and water. To analyze the spatio-temporal changes of humidifying effect of green lands at the spring daytime, the authors monitored the air humidity within 1.8 m high from various underlying surfaces, including arbor-grass lands, shrub lands, herb lands and a cement pavement, from late February to late April in 2015 and 2016, when it was sunny and windless, in the Yuxi park of Shijiazhuang. The results were compared with the monitoring data of a bare land(190 m×120 m) without environmental interventions such as vegetation and water. The results could be summarized as follows:(1) The humidifying effect of green spaces was the weakest at 8:00 a.m. during the late February, whereas it was the strongest at 10:00 a.m.; from late March to late April, the humidifying effect of green spaces strengthened with the increase of air temperature, and the strongest was noted around 12:00-16:00.(2) The humidifying effect of various types of green lands was the strongest close to the ground, and reduced from 0.2 m to 1.8 m. This vertical stratification became apparent after the plants sprouted, the vertical difference of humidifying effect was the most significant in the herb lands, less significant in arbor-grass lands, and least in the shrub lands.(3) Multiple comparison analysis of the humidity data showed that relative humidity of all green lands achieved the significant level(P < 0.05), indicating the strong effect of landscape plants in adjusting atmospheric humidity in spring.(4) The humidifying effect of the artificial lake was more remarkable before the plants sprouted, however, with the rapid growth of plant leaves, theeffect gradually reduced and became even weaker than the effect of vegetation. Although the humidifying effect in spring was weaker than that in summer and autumn, the effect of humidification was more complicated during the growth of green leaves in spring than in summer and autumn. This is useful to construct the theory system of ecological environment effect of green lands in spring, summer and autumn.
文摘We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zhaiye- qing 8),96E80[(IR 24/Guanglu＇ai 4//Zhongnan’ai)/Yifengzao],96E86(Zhong- munong 9/Zhaiyeqing 8).The induction mediaused was M8+2mg/L 2,4-D,and agar con-centrations were 0.6％,0.8％,and 1.0％,respectively.Regeneration media was MS+2mg/L KT+0.5mg/L IAA+0.5mg/LNAA,and agar concentrations were 0.6％ and1.0％.Results indicated that the calli induc-
文摘The accelerating urbanization process and intensifying climate change have exacerbated the urban heat island effect, threatening sustainable urban development. This study investigates the role of green infrastructure in mitigating urban heat island effects, its implementation challenges, and applications. Employing a system dynamics approach, the research models the relationships between green infrastructure, urban microclimate, and human well-being. Findings indicate that large, continuous green spaces, such as urban parks and green corridors, are most effective, potentially reducing surrounding temperatures by 1˚C - 4˚C. Green infrastructure also provides multiple ecosystem services, including improved air quality and increased biodiversity. However, its implementation faces challenges such as land resource limitations and financial constraints. To address these issues, the study proposes a performance-based planning method, emphasizing multifunctional design and cross-sectoral collaboration. Through analysis of international and Chinese urban case studies, best practices and lessons learned are summarized. The research demonstrates that successful strategies must be context-specific, integrating local conditions while emphasizing long-term planning and continuous optimization. This study provides a scientific basis for developing effective heat island mitigation strategies and climate adaptation plans, ultimately achieving sustainable urban development and improved living environments.
文摘Wild rice is an important resource of usefulgenes to rice breeders. However, low regener-ation frequency is an obstacle to use the valu-able genes. We used desiccation to improve theregeneration frequency and studied the bio-chemical changes of calli of wild rice after des-iccation.Materials used in this experiment werewild species O. rufipogon, O. meyeriana, O.alta, and O. brachyantha. Young panicles(0.1-0. 5 cm in length of the inflorescence)
基金Project supported by the Natural Science Foundation of Jiangxi Province (No. 0450035).
文摘A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes three elastic constants of single cubic crystal and ?ve texture coe?cients, accounts for the e?ects of the orientation distribution function (ODF) up to terms linear in the tex- ture coe?cients. Thus it is expected that our formula would be applicable to arbitrary aggregates with weak texture or to materials such as aluminum whose single crystal has weak anisotropy. Three examples are presented to compare predictions from our formula with those from Nishioka and Lothe’s formula and Synge’s contour integral through numerical integration. As an applica- tion of Green’s function, we brie?y describe the procedure of deriving the e?ective elastic sti?ness tensor for an orthorhombic aggregate of cubic crystallites. The comparison of the computational results given by the ?nite element method and our e?ective elastic sti?ness tensor is made by an example.
基金Project supported by the Science and Technology Planning Project of Zhejiang Province,China(Grant No.2018C01046)Enterprise-funded Latitudinal Research Projects,China(Grant Nos.J2016-141,J2017-171,J2017-293,and J2017-243)
文摘The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.
