Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surfa...Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020.To compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads.Across Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic zone.EZD values vary from 6-154 m for the study area,and it has an inverse correlation with NPP concentration.EZD is deeper during the summer season and shallower during the wintertime,with a corresponding increase in productivity.Throughout the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern BoB.Long-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open ocean.The findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost relevance to the fisheries for the three bordering countries.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
High temperature is one of the most important environmental factors that affect the successful cultivation of apple (Malus × domestica Borkh). The expression of genes related with anthocyanin synthesis and sugar ...High temperature is one of the most important environmental factors that affect the successful cultivation of apple (Malus × domestica Borkh). The expression of genes related with anthocyanin synthesis and sugar accumulation by high temperature treatment was investigated in the fruits of “Fuji” apple at different developmental stages in different temperature conditions through real- time PCR. In the initial ripening stages in fruits, there was high expression of genes associated with fruit ripening, flavonoid compound accumulation, and coloration in high temperatures. Expression of phenylalanine ammonia-lyase, chalcone synthase, flavone 3-hydrogenase, and malate dehydrogenase genes increased gradually in initial ripening stages, while sharply reduced at 24 hr after treatment. In addition, there was no significant difference in the expression of all temperature treatments in late ripening stages. In the further work, investigation of expression levels of various genes could be conducted in the level of transcriptomes from fruits at the early stages to get meaningful information of ripening metabolism in apples in high temperatures.展开更多
A 3D temperature field reconstruction method using the colored background oriented schlieren(CBOS)method is proposed to address image blurring due to the different refractive index of the multi-wavelength light and si...A 3D temperature field reconstruction method using the colored background oriented schlieren(CBOS)method is proposed to address image blurring due to the different refractive index of the multi-wavelength light and significant errors produced when the traditional background oriented schlieren(BOS)method is applied to high-temperature gas.First,the traditional method is employed to reconstruct the non-uniform 3D temperature field.Second,the CBOS method is applied to correct the distortion.Then,by analyzing the correlation coefficient among different color points of the colored background pattern,the non-uniform temperature field is reconstructed much more accurately.Finally,the experimental results are verified by applying the Runge-Kutta ray-tracing method and the thermocouple contact measurement method.The maximum average temperature error of the CBOS-reconstructed temperature field is 12.92°C,compared with the thermocouples.Therefore,an accurate three-dimensional reconstruction of the temperature field can be achieved by the proposed method effectively.展开更多
A new approach has been proposed to improve the performance of the in-telligent lighting system by estimating personal illuminance and desired color temperature at the workplace. We are considering the problem of usin...A new approach has been proposed to improve the performance of the in-telligent lighting system by estimating personal illuminance and desired color temperature at the workplace. We are considering the problem of using the sensing devices manually for the intelligent lighting system. The lighting control system has not become useful without sensing devices to measure the provided illuminance and color temperature. In this paper, we have used the property of light for the color temperature to estimate the level of color temperature for each user at the workplace. The new method will give personal illuminance for each user at the workplace and decrease the power consumption of the environment as well. As a result, the proposed method of the intelligent lighting system has realized the target of illuminance and color temperature for each user at the workplace by adapting dimming levels using illuminance sensing information for each user. Thus, the energy of the workplace has reduced by using a distributed luminance to realize the target for each user.展开更多
Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important pa...Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important parameter to measure the performance of CT-OLEDs. In this paper, the effect of changing the utilization of phosphorescent materials and the position of the recombination zone (RZ) in the device are investigated by changing the thickness of the emissive layer (EML) and the doping ratio of the host and guest materials. The results show that reducing the red phosphorescent material and improving the blue phosphorescent material can affect the change direction of CCT, but it is not enough to expand the span of CCT (ΔCCT). It is more conducive to improving ΔCCT by more reasonable regulation of the position of the main RZ in EML and the energy transfer from the blue sub-EML to the red sub-EML. Device D obtains the best electro-optic and spectral characteristics, in which the maximum ΔCCT is 5746 K (2661 - 8407 K) as the voltage changes from 3.75 V to 9.75 V, the maximum current efficiency and luminance reach 18.34 cd·A<sup>-1</sup> and 12,100 cd·m<sup>-2</sup>, respectively.展开更多
Colors were generated by preferential oxidation of the metals in coloring hot dip galvanization process, and the evolution of temperature field during cooling after hot dip would be responsible for the coloration resu...Colors were generated by preferential oxidation of the metals in coloring hot dip galvanization process, and the evolution of temperature field during cooling after hot dip would be responsible for the coloration results directly. The influences of bath temperature and velocity of steel strip moving on temperature field of the strip were calculated in continuous coloring hot dip galvanization process by means of the ANSYS/Thermal module. The factors were considered including convection heat transfer, latent heat during cooling, and heat radiation in calculation. The effects of temperature field on coloration of sheet steel samples were investigated.展开更多
This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene gly...This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene glycol, the vapor pressure of which is much lower than that of water, as the solvent of the fluorescent dyes. A supersonic moisture chamber is used as the atomizer for seeding the tracer particles to be visualized. The proposed technique is applied to the measurement of the temperature distribution in a thermal vertical buoyant plume. The proposed two-color LIF thermometry is found to be very effective for the study of such a thermal structure, and it is well suited for measuring the temperature field of an airflow.展开更多
Color variation among populations is thought to be either due to genetic variation or phenotype plasticity.In this study,we found that an agamid lizard,Phrynocephalus theobaldi,inhabiting elevations greater than any o...Color variation among populations is thought to be either due to genetic variation or phenotype plasticity.In this study,we found that an agamid lizard,Phrynocephalus theobaldi,inhabiting elevations greater than any other reptile,displayed a significantly darker spotted marking on the central ventral abdomen in higher populations than in lower populations.The grey spotted area only occurred in elevations>4200 m,and also increased with increased elevation.The ratio of the size of the dark colored area to the degree of skin luminance/reflectance was used to test whether the lizard has a larger and darker spotted area at higher elevations.This ratio was significantly positively associated with elevation rather than substrate color.The lizard did not display sexual difference in this phenotype.Temperature had a significant influence on the brightness of central abdomen,but temperature-related plasticity of this trait was much smaller than the magnitude of the difference between higher(>4200 m)and lower populations(<4200 m).Common garden experiments showed that genetic inheritance,rather than phenotype plasticity,played a dominant role in this variation.Our research addressed the darkness of a body region that is rarely analyzed because it is shielded from direct insolation.The idea that ventral color could be related to thermoregulation is shown to be worthy of further research.展开更多
We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable ma...We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable material generates broad bandwidth emission at the visible range. Increasing the amount of gold nanoclusters, the correlated color temperature of WLEDs tuned from cold white to warm white, and also results in the variation of color rendering index (CRI). The highest CRI in the experiment is 92.展开更多
Building on the recent systematic research on 1Hbenzo[f]indole(Bd),an important advancement in constructing ultralong organic room temperature(UORTP)materials with a universal strategy via a readily obtained unit(7H-B...Building on the recent systematic research on 1Hbenzo[f]indole(Bd),an important advancement in constructing ultralong organic room temperature(UORTP)materials with a universal strategy via a readily obtained unit(7H-Benzo[c]carbazole,BCz)is proposed in this work.Pure powders of BCz and its derivatives merely exhibit blue fluorescence at ambient condition.However,when BCz and its derivatives are dispersed into polymer or powder matrixes,strong photo-activated green UORTP can be observed from their doped systems at room temperature.Moreover,the UORTP color can be tuned between green and yellow depending on the matrix.The ultralong phosphorescence originates from the generation of charge-separated states via radicals.The matrixes play a key role in both stabilizing charge-separated states and controlling UORTP color.More interestingly,when using polymethyl methacrylate as matrix,the doped films achieve stronger photo-activated ultralong phosphorescence underwater than in air at room temperature.Comparedwith Bd,BCz achieves better performance not only in ultralong phosphorescence properties but also in practical applications.This work gains a deeper insight into the mechanism of UORTP and paves a new approach to applying organic phosphorescent materials to underwater coating and imaging.展开更多
Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, bu...Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury. The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears. Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene (1-MCP), combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage. We found that 1-MCP and/or low temperature reduced the loss of green color at 20℃ after being removed from cold storage. In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids. Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage. Different storage temperatures had different effects on the quality of Korla Xiang pears. Despite inhibiting ethylene release, a storage temperature of-1.5℃ increased the respiration rate. Storage at -1.5℃ caused core browning eady during storage due to chilling injury, whereas at 2℃ core browning occurred late during storage due to senescence. In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2℃. Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury. For different marketing times, the optimal conditions for storage until New Year's Day (a storage duration of 90 days) are 2℃ or 1-MCP combined with 2℃. For storage until the Spring Festival (a storage duration of 150 days), the optimal conditions are 0℃ or 1-MCP combined with 0℃, and for storage until May (a storage duration of 225 days), the best conditions are 1-MCP combined with -1.5℃.展开更多
Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond c...Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond crystals changed from colorless to yellow and finally to atrovirens(a dark green).All the Raman peaks for the obtained crystals were located at about 1330 cm^(-1)and contained only the sp^(3)hybrid diamond phase.Based on Fourier transform infrared results,the nitrogen concentration of the colorless diamond was<1 ppm and absorption peaks corresponding to nitrogen impurities were not detected.However,the C-center nitrogen concentration of the atrovirens diamond reached 1030 ppm and the value of A-center nitrogen was approximately 180 ppm with a characteristic absorption peak at 1282 cm^(-1).Furthermore,neither the NV^(0)nor the NV^(-)optical color center existed in diamond crystal with nitrogen impurities of less than 1 ppm by photoluminescence measurement.However,Ni-related centers located at 695 nm and 793.6 nm were observed in colorless diamond.The NE8 color center at 793.6 nm has more potential for application than the common NV centers.NV^(0)and NV^(-)optical color centers coexist in diamond without any additives in the synthesis system.Importantly,only the NV^(-)color center was noticed in diamond with a higher nitrogen concentration,which maximized optimization of the NV^(-)/NV^(0)ratio in the diamond structure.This study has provided a new way to prepare diamond containing only NV^(-)optical color centers.展开更多
A laboratory experiment has been designed and implemented to study the effects of storage temperatures (27.5°C and 37.5°C) and storage periods (day, 3 days, 10 days, 20 days and 30 days) in normal conditions...A laboratory experiment has been designed and implemented to study the effects of storage temperatures (27.5°C and 37.5°C) and storage periods (day, 3 days, 10 days, 20 days and 30 days) in normal conditions and relative humidity on the characteristics of wheat flour quality, as well as some of the chemical characteristics of flour (moisture content and ratio of wet gluten), the physical properties (color and falling number). Increasing the storage temperature from 27.5°C to 37.5°C has led to decreasing moisture content of flour stored under storage relative humidity of 38% - 70%. It has also resulted in extending the storage period from 1 day to 10 days to a decrease in moisture content of flour, and this decline has increased the storage period up to thirty days. The overlap between these two factors has been significantly affective. As the storage temperature of flour increased from 27.5°C to 37.5°C, the percentage of wet gluten has been increased too, and the storage period was extended to ten days. This has led to a significant increase in the percentage of wet gluten flour. In addition, there was a significant response to the effective overlap between the storage temperatures and periods of storage under study in this manner. Increasing the storage temperature from 27.5°C to 37.5°C has led to significantly increased values of the color of the stored flour. Besides, increasing the storage period one day more has led to decreasing the values of the color of the stored flour. However, there has been no significant change to the subsequent periods of storage. The overlap between both factors of temperature and storage periods has a significant effect on the flour color. There has been a significant decrease of the enzyme activity (the height values of the falling No.). But there is a noticeable increase to the falling No. values of the stored flour by 37.5°C when increasing the storage periods from one day to ten days and thirty days. This effect, nonetheless, has not reached the significant level.展开更多
Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive succe...Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive success. Quisqualis indica L.(Combretaceae) is a tropical Asian climber that undergoes sequential petal color change from white to pink to red. This color changing process is thought to be a good strategy to attract more pollinators. However, the underlying physiological and biochemical mechanisms driving this petal color change phenomenon is still underexplored. In this context, we investigated whether changes in pH, pollination, light, temperature or ethylene mediate petal color change. We found that the detected changes in petal pH were not significant enough to induce color alterations. Additionally, pollination and temperatures of 20-30℃did not alter the rate of petal color change; however, flowers did not open when exposed to constant temperatures at 15℃ or 35℃.Moreover, the application of ethylene inhibitor, i.e., silver thiosulphate, did not prevent color change. It is worth mentioning here that in our study we found light as a strong factor influencing the whole process of petal color change, as petals remained white under dark conditions. Altogether, the present study suggests that petal color change in Q. indica is induced by light and not by changes in petal pH, pollination, ethylene, or temperature, while extremely low or high temperatures affect flower anthesis. In summary, our findings represent the probable mechanism underlying the phenomenon of petal color change, which is important for understanding flower color evolution.展开更多
Color information plays a key role in the research fields of object recognition and image retrieval. However, the actual color varies by the conditions of illumination, especially the open natural daylight. Four diffe...Color information plays a key role in the research fields of object recognition and image retrieval. However, the actual color varies by the conditions of illumination, especially the open natural daylight. Four different color constancy schemes are proposed in the paper to minimize the effects of open illumination conditions. (1) The color constancy scheme based on the image statistics is proposed, which includes the color cast detection and removal. (2) The color constancy scheme based on the color temperature curve is proposed, which combines Gaussian model with linear fitting to estimate color temperature curve. (3) The color constancy scheme based on the double exposure theory is proposed, which is able to reproduce a color image under typical illumination. (4) According to the concepts of supervised learning, the supervised color constancy scheme is proposed. The transformation of color values from unknown illumination to typical illumination is solved by improved Support Vector Regression (SVR).展开更多
A radiation–temperature coupling model of optical fiber attenuation spectrum has been developed.The spectrum in Ge/P co-doped fiber ranging from 800 nm–1600 nm at different temperatures and doses was measured and de...A radiation–temperature coupling model of optical fiber attenuation spectrum has been developed.The spectrum in Ge/P co-doped fiber ranging from 800 nm–1600 nm at different temperatures and doses was measured and decomposed according to the configurational coordinate model based on which the power-law model was employed to predict the intensity of the color center absorption band at different doses.And the fiber loss in space was predicted by the model.This work will benefit the application of fibers in a complicated radiation environment.展开更多
Chlorophylls and carotenoids are the main pigments in leaves of higher plants. They combine to give color to leaves. Based on the CIE1931 chromaticity coordinates of chlorophylls and cartotenoids, which were obtained ...Chlorophylls and carotenoids are the main pigments in leaves of higher plants. They combine to give color to leaves. Based on the CIE1931 chromaticity coordinates of chlorophylls and cartotenoids, which were obtained from their classical absorption spectra and the law of additive color mixing, the theoretical color gamut of higher plant leaves is determined. The theoretical prediction agrees well with our experimental results.展开更多
基金The US Department of State for sponsoring undergraduate exchange program。
文摘Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020.To compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads.Across Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic zone.EZD values vary from 6-154 m for the study area,and it has an inverse correlation with NPP concentration.EZD is deeper during the summer season and shallower during the wintertime,with a corresponding increase in productivity.Throughout the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern BoB.Long-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open ocean.The findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost relevance to the fisheries for the three bordering countries.
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.
文摘High temperature is one of the most important environmental factors that affect the successful cultivation of apple (Malus × domestica Borkh). The expression of genes related with anthocyanin synthesis and sugar accumulation by high temperature treatment was investigated in the fruits of “Fuji” apple at different developmental stages in different temperature conditions through real- time PCR. In the initial ripening stages in fruits, there was high expression of genes associated with fruit ripening, flavonoid compound accumulation, and coloration in high temperatures. Expression of phenylalanine ammonia-lyase, chalcone synthase, flavone 3-hydrogenase, and malate dehydrogenase genes increased gradually in initial ripening stages, while sharply reduced at 24 hr after treatment. In addition, there was no significant difference in the expression of all temperature treatments in late ripening stages. In the further work, investigation of expression levels of various genes could be conducted in the level of transcriptomes from fruits at the early stages to get meaningful information of ripening metabolism in apples in high temperatures.
基金Supported by the National Natural Science Foundation of China(52005500)Foundation of Tianjin Educational Committee(2018KJ242)Basic Science-Research Funds of National University(3122019088)。
文摘A 3D temperature field reconstruction method using the colored background oriented schlieren(CBOS)method is proposed to address image blurring due to the different refractive index of the multi-wavelength light and significant errors produced when the traditional background oriented schlieren(BOS)method is applied to high-temperature gas.First,the traditional method is employed to reconstruct the non-uniform 3D temperature field.Second,the CBOS method is applied to correct the distortion.Then,by analyzing the correlation coefficient among different color points of the colored background pattern,the non-uniform temperature field is reconstructed much more accurately.Finally,the experimental results are verified by applying the Runge-Kutta ray-tracing method and the thermocouple contact measurement method.The maximum average temperature error of the CBOS-reconstructed temperature field is 12.92°C,compared with the thermocouples.Therefore,an accurate three-dimensional reconstruction of the temperature field can be achieved by the proposed method effectively.
文摘A new approach has been proposed to improve the performance of the in-telligent lighting system by estimating personal illuminance and desired color temperature at the workplace. We are considering the problem of using the sensing devices manually for the intelligent lighting system. The lighting control system has not become useful without sensing devices to measure the provided illuminance and color temperature. In this paper, we have used the property of light for the color temperature to estimate the level of color temperature for each user at the workplace. The new method will give personal illuminance for each user at the workplace and decrease the power consumption of the environment as well. As a result, the proposed method of the intelligent lighting system has realized the target of illuminance and color temperature for each user at the workplace by adapting dimming levels using illuminance sensing information for each user. Thus, the energy of the workplace has reduced by using a distributed luminance to realize the target for each user.
文摘Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important parameter to measure the performance of CT-OLEDs. In this paper, the effect of changing the utilization of phosphorescent materials and the position of the recombination zone (RZ) in the device are investigated by changing the thickness of the emissive layer (EML) and the doping ratio of the host and guest materials. The results show that reducing the red phosphorescent material and improving the blue phosphorescent material can affect the change direction of CCT, but it is not enough to expand the span of CCT (ΔCCT). It is more conducive to improving ΔCCT by more reasonable regulation of the position of the main RZ in EML and the energy transfer from the blue sub-EML to the red sub-EML. Device D obtains the best electro-optic and spectral characteristics, in which the maximum ΔCCT is 5746 K (2661 - 8407 K) as the voltage changes from 3.75 V to 9.75 V, the maximum current efficiency and luminance reach 18.34 cd·A<sup>-1</sup> and 12,100 cd·m<sup>-2</sup>, respectively.
文摘Colors were generated by preferential oxidation of the metals in coloring hot dip galvanization process, and the evolution of temperature field during cooling after hot dip would be responsible for the coloration results directly. The influences of bath temperature and velocity of steel strip moving on temperature field of the strip were calculated in continuous coloring hot dip galvanization process by means of the ANSYS/Thermal module. The factors were considered including convection heat transfer, latent heat during cooling, and heat radiation in calculation. The effects of temperature field on coloration of sheet steel samples were investigated.
文摘This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene glycol, the vapor pressure of which is much lower than that of water, as the solvent of the fluorescent dyes. A supersonic moisture chamber is used as the atomizer for seeding the tracer particles to be visualized. The proposed technique is applied to the measurement of the temperature distribution in a thermal vertical buoyant plume. The proposed two-color LIF thermometry is found to be very effective for the study of such a thermal structure, and it is well suited for measuring the temperature field of an airflow.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019 QZKK0501)the National Natural Science Foundation of China(Grant No.31772447)Zhejiang Natural Science Foundation(LY21C040002)。
文摘Color variation among populations is thought to be either due to genetic variation or phenotype plasticity.In this study,we found that an agamid lizard,Phrynocephalus theobaldi,inhabiting elevations greater than any other reptile,displayed a significantly darker spotted marking on the central ventral abdomen in higher populations than in lower populations.The grey spotted area only occurred in elevations>4200 m,and also increased with increased elevation.The ratio of the size of the dark colored area to the degree of skin luminance/reflectance was used to test whether the lizard has a larger and darker spotted area at higher elevations.This ratio was significantly positively associated with elevation rather than substrate color.The lizard did not display sexual difference in this phenotype.Temperature had a significant influence on the brightness of central abdomen,but temperature-related plasticity of this trait was much smaller than the magnitude of the difference between higher(>4200 m)and lower populations(<4200 m).Common garden experiments showed that genetic inheritance,rather than phenotype plasticity,played a dominant role in this variation.Our research addressed the darkness of a body region that is rarely analyzed because it is shielded from direct insolation.The idea that ventral color could be related to thermoregulation is shown to be worthy of further research.
文摘We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable material generates broad bandwidth emission at the visible range. Increasing the amount of gold nanoclusters, the correlated color temperature of WLEDs tuned from cold white to warm white, and also results in the variation of color rendering index (CRI). The highest CRI in the experiment is 92.
基金supported by the National Natural Science Foundation of China(grant nos.22175015 and 21704002)the Beijing Natural Science Foundation(grant no.2182054)+1 种基金the Big Science Project from BUCT(grant no.XK180301)the Fundamental Research Funds for the Central Universities to Z.Y.Ma.
文摘Building on the recent systematic research on 1Hbenzo[f]indole(Bd),an important advancement in constructing ultralong organic room temperature(UORTP)materials with a universal strategy via a readily obtained unit(7H-Benzo[c]carbazole,BCz)is proposed in this work.Pure powders of BCz and its derivatives merely exhibit blue fluorescence at ambient condition.However,when BCz and its derivatives are dispersed into polymer or powder matrixes,strong photo-activated green UORTP can be observed from their doped systems at room temperature.Moreover,the UORTP color can be tuned between green and yellow depending on the matrix.The ultralong phosphorescence originates from the generation of charge-separated states via radicals.The matrixes play a key role in both stabilizing charge-separated states and controlling UORTP color.More interestingly,when using polymethyl methacrylate as matrix,the doped films achieve stronger photo-activated ultralong phosphorescence underwater than in air at room temperature.Comparedwith Bd,BCz achieves better performance not only in ultralong phosphorescence properties but also in practical applications.This work gains a deeper insight into the mechanism of UORTP and paves a new approach to applying organic phosphorescent materials to underwater coating and imaging.
基金supported by a grant from the National Key R&D Program of China (2016YFD0400903-06)the emarked fund for China Agriculture Research System (CARS-29-19)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2016-RIP-06)
文摘Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury. The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears. Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene (1-MCP), combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage. We found that 1-MCP and/or low temperature reduced the loss of green color at 20℃ after being removed from cold storage. In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids. Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage. Different storage temperatures had different effects on the quality of Korla Xiang pears. Despite inhibiting ethylene release, a storage temperature of-1.5℃ increased the respiration rate. Storage at -1.5℃ caused core browning eady during storage due to chilling injury, whereas at 2℃ core browning occurred late during storage due to senescence. In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2℃. Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury. For different marketing times, the optimal conditions for storage until New Year's Day (a storage duration of 90 days) are 2℃ or 1-MCP combined with 2℃. For storage until the Spring Festival (a storage duration of 150 days), the optimal conditions are 0℃ or 1-MCP combined with 0℃, and for storage until May (a storage duration of 225 days), the best conditions are 1-MCP combined with -1.5℃.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12064038 and 52072113)the Natural Science Foundation of Guizhou Province Science and Technology Agency(Grant Nos.ZK[2021]019 and ZK[2021]031)+1 种基金the Outstanding Young Science and Technology Talents of Guizhou Pronice,China(Grant No.[2019]5673)the Open Project of Inner Mongolia Key Lab of High-pressure Phase Functional Materials(Grant No.cfxygy202004)。
文摘Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond crystals changed from colorless to yellow and finally to atrovirens(a dark green).All the Raman peaks for the obtained crystals were located at about 1330 cm^(-1)and contained only the sp^(3)hybrid diamond phase.Based on Fourier transform infrared results,the nitrogen concentration of the colorless diamond was<1 ppm and absorption peaks corresponding to nitrogen impurities were not detected.However,the C-center nitrogen concentration of the atrovirens diamond reached 1030 ppm and the value of A-center nitrogen was approximately 180 ppm with a characteristic absorption peak at 1282 cm^(-1).Furthermore,neither the NV^(0)nor the NV^(-)optical color center existed in diamond crystal with nitrogen impurities of less than 1 ppm by photoluminescence measurement.However,Ni-related centers located at 695 nm and 793.6 nm were observed in colorless diamond.The NE8 color center at 793.6 nm has more potential for application than the common NV centers.NV^(0)and NV^(-)optical color centers coexist in diamond without any additives in the synthesis system.Importantly,only the NV^(-)color center was noticed in diamond with a higher nitrogen concentration,which maximized optimization of the NV^(-)/NV^(0)ratio in the diamond structure.This study has provided a new way to prepare diamond containing only NV^(-)optical color centers.
文摘A laboratory experiment has been designed and implemented to study the effects of storage temperatures (27.5°C and 37.5°C) and storage periods (day, 3 days, 10 days, 20 days and 30 days) in normal conditions and relative humidity on the characteristics of wheat flour quality, as well as some of the chemical characteristics of flour (moisture content and ratio of wet gluten), the physical properties (color and falling number). Increasing the storage temperature from 27.5°C to 37.5°C has led to decreasing moisture content of flour stored under storage relative humidity of 38% - 70%. It has also resulted in extending the storage period from 1 day to 10 days to a decrease in moisture content of flour, and this decline has increased the storage period up to thirty days. The overlap between these two factors has been significantly affective. As the storage temperature of flour increased from 27.5°C to 37.5°C, the percentage of wet gluten has been increased too, and the storage period was extended to ten days. This has led to a significant increase in the percentage of wet gluten flour. In addition, there was a significant response to the effective overlap between the storage temperatures and periods of storage under study in this manner. Increasing the storage temperature from 27.5°C to 37.5°C has led to significantly increased values of the color of the stored flour. Besides, increasing the storage period one day more has led to decreasing the values of the color of the stored flour. However, there has been no significant change to the subsequent periods of storage. The overlap between both factors of temperature and storage periods has a significant effect on the flour color. There has been a significant decrease of the enzyme activity (the height values of the falling No.). But there is a noticeable increase to the falling No. values of the stored flour by 37.5°C when increasing the storage periods from one day to ten days and thirty days. This effect, nonetheless, has not reached the significant level.
基金funded by a grant from the National Nature Science Foundation of China(31670393 and 31170406)that was awarded to L.Zhang
文摘Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive success. Quisqualis indica L.(Combretaceae) is a tropical Asian climber that undergoes sequential petal color change from white to pink to red. This color changing process is thought to be a good strategy to attract more pollinators. However, the underlying physiological and biochemical mechanisms driving this petal color change phenomenon is still underexplored. In this context, we investigated whether changes in pH, pollination, light, temperature or ethylene mediate petal color change. We found that the detected changes in petal pH were not significant enough to induce color alterations. Additionally, pollination and temperatures of 20-30℃did not alter the rate of petal color change; however, flowers did not open when exposed to constant temperatures at 15℃ or 35℃.Moreover, the application of ethylene inhibitor, i.e., silver thiosulphate, did not prevent color change. It is worth mentioning here that in our study we found light as a strong factor influencing the whole process of petal color change, as petals remained white under dark conditions. Altogether, the present study suggests that petal color change in Q. indica is induced by light and not by changes in petal pH, pollination, ethylene, or temperature, while extremely low or high temperatures affect flower anthesis. In summary, our findings represent the probable mechanism underlying the phenomenon of petal color change, which is important for understanding flower color evolution.
基金Supported by the National Natural Science Foundation of China (No.60431020)the Natural Science Foundation of Beijing (No.3052005)the Ph.D. Foundation of Ministry of Education (No.20040005015)
文摘Color information plays a key role in the research fields of object recognition and image retrieval. However, the actual color varies by the conditions of illumination, especially the open natural daylight. Four different color constancy schemes are proposed in the paper to minimize the effects of open illumination conditions. (1) The color constancy scheme based on the image statistics is proposed, which includes the color cast detection and removal. (2) The color constancy scheme based on the color temperature curve is proposed, which combines Gaussian model with linear fitting to estimate color temperature curve. (3) The color constancy scheme based on the double exposure theory is proposed, which is able to reproduce a color image under typical illumination. (4) According to the concepts of supervised learning, the supervised color constancy scheme is proposed. The transformation of color values from unknown illumination to typical illumination is solved by improved Support Vector Regression (SVR).
文摘A radiation–temperature coupling model of optical fiber attenuation spectrum has been developed.The spectrum in Ge/P co-doped fiber ranging from 800 nm–1600 nm at different temperatures and doses was measured and decomposed according to the configurational coordinate model based on which the power-law model was employed to predict the intensity of the color center absorption band at different doses.And the fiber loss in space was predicted by the model.This work will benefit the application of fibers in a complicated radiation environment.
基金This work is supported by the Foundation of the China National Natural Sciences (Grant No.59006487)the Special Foundationfor Doctoral Programof the Ministry of Education (Grant No.97035821)
文摘Chlorophylls and carotenoids are the main pigments in leaves of higher plants. They combine to give color to leaves. Based on the CIE1931 chromaticity coordinates of chlorophylls and cartotenoids, which were obtained from their classical absorption spectra and the law of additive color mixing, the theoretical color gamut of higher plant leaves is determined. The theoretical prediction agrees well with our experimental results.